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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ring buffer based function tracer
4 *
5 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Originally taken from the RT patch by:
9 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 *
11 * Based on code from the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 Nadia Yvette Chambers
14 */
15#include <linux/ring_buffer.h>
16#include <generated/utsrelease.h>
17#include <linux/stacktrace.h>
18#include <linux/writeback.h>
19#include <linux/kallsyms.h>
20#include <linux/security.h>
21#include <linux/seq_file.h>
22#include <linux/irqflags.h>
23#include <linux/debugfs.h>
24#include <linux/tracefs.h>
25#include <linux/pagemap.h>
26#include <linux/hardirq.h>
27#include <linux/linkage.h>
28#include <linux/uaccess.h>
29#include <linux/vmalloc.h>
30#include <linux/ftrace.h>
31#include <linux/module.h>
32#include <linux/percpu.h>
33#include <linux/splice.h>
34#include <linux/kdebug.h>
35#include <linux/string.h>
36#include <linux/mount.h>
37#include <linux/rwsem.h>
38#include <linux/slab.h>
39#include <linux/ctype.h>
40#include <linux/init.h>
41#include <linux/panic_notifier.h>
42#include <linux/kmemleak.h>
43#include <linux/poll.h>
44#include <linux/nmi.h>
45#include <linux/fs.h>
46#include <linux/trace.h>
47#include <linux/sched/clock.h>
48#include <linux/sched/rt.h>
49#include <linux/fsnotify.h>
50#include <linux/irq_work.h>
51#include <linux/workqueue.h>
52
53#include <asm/setup.h> /* COMMAND_LINE_SIZE */
54
55#include "trace.h"
56#include "trace_output.h"
57
58#ifdef CONFIG_FTRACE_STARTUP_TEST
59/*
60 * We need to change this state when a selftest is running.
61 * A selftest will lurk into the ring-buffer to count the
62 * entries inserted during the selftest although some concurrent
63 * insertions into the ring-buffer such as trace_printk could occurred
64 * at the same time, giving false positive or negative results.
65 */
66static bool __read_mostly tracing_selftest_running;
67
68/*
69 * If boot-time tracing including tracers/events via kernel cmdline
70 * is running, we do not want to run SELFTEST.
71 */
72bool __read_mostly tracing_selftest_disabled;
73
74void __init disable_tracing_selftest(const char *reason)
75{
76 if (!tracing_selftest_disabled) {
77 tracing_selftest_disabled = true;
78 pr_info("Ftrace startup test is disabled due to %s\n", reason);
79 }
80}
81#else
82#define tracing_selftest_running 0
83#define tracing_selftest_disabled 0
84#endif
85
86/* Pipe tracepoints to printk */
87static struct trace_iterator *tracepoint_print_iter;
88int tracepoint_printk;
89static bool tracepoint_printk_stop_on_boot __initdata;
90static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
91
92/* For tracers that don't implement custom flags */
93static struct tracer_opt dummy_tracer_opt[] = {
94 { }
95};
96
97static int
98dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
99{
100 return 0;
101}
102
103/*
104 * To prevent the comm cache from being overwritten when no
105 * tracing is active, only save the comm when a trace event
106 * occurred.
107 */
108static DEFINE_PER_CPU(bool, trace_taskinfo_save);
109
110/*
111 * Kill all tracing for good (never come back).
112 * It is initialized to 1 but will turn to zero if the initialization
113 * of the tracer is successful. But that is the only place that sets
114 * this back to zero.
115 */
116static int tracing_disabled = 1;
117
118cpumask_var_t __read_mostly tracing_buffer_mask;
119
120/*
121 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
122 *
123 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
124 * is set, then ftrace_dump is called. This will output the contents
125 * of the ftrace buffers to the console. This is very useful for
126 * capturing traces that lead to crashes and outputing it to a
127 * serial console.
128 *
129 * It is default off, but you can enable it with either specifying
130 * "ftrace_dump_on_oops" in the kernel command line, or setting
131 * /proc/sys/kernel/ftrace_dump_on_oops
132 * Set 1 if you want to dump buffers of all CPUs
133 * Set 2 if you want to dump the buffer of the CPU that triggered oops
134 */
135
136enum ftrace_dump_mode ftrace_dump_on_oops;
137
138/* When set, tracing will stop when a WARN*() is hit */
139int __disable_trace_on_warning;
140
141#ifdef CONFIG_TRACE_EVAL_MAP_FILE
142/* Map of enums to their values, for "eval_map" file */
143struct trace_eval_map_head {
144 struct module *mod;
145 unsigned long length;
146};
147
148union trace_eval_map_item;
149
150struct trace_eval_map_tail {
151 /*
152 * "end" is first and points to NULL as it must be different
153 * than "mod" or "eval_string"
154 */
155 union trace_eval_map_item *next;
156 const char *end; /* points to NULL */
157};
158
159static DEFINE_MUTEX(trace_eval_mutex);
160
161/*
162 * The trace_eval_maps are saved in an array with two extra elements,
163 * one at the beginning, and one at the end. The beginning item contains
164 * the count of the saved maps (head.length), and the module they
165 * belong to if not built in (head.mod). The ending item contains a
166 * pointer to the next array of saved eval_map items.
167 */
168union trace_eval_map_item {
169 struct trace_eval_map map;
170 struct trace_eval_map_head head;
171 struct trace_eval_map_tail tail;
172};
173
174static union trace_eval_map_item *trace_eval_maps;
175#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
176
177int tracing_set_tracer(struct trace_array *tr, const char *buf);
178static void ftrace_trace_userstack(struct trace_array *tr,
179 struct trace_buffer *buffer,
180 unsigned int trace_ctx);
181
182#define MAX_TRACER_SIZE 100
183static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
184static char *default_bootup_tracer;
185
186static bool allocate_snapshot;
187static bool snapshot_at_boot;
188
189static char boot_instance_info[COMMAND_LINE_SIZE] __initdata;
190static int boot_instance_index;
191
192static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata;
193static int boot_snapshot_index;
194
195static int __init set_cmdline_ftrace(char *str)
196{
197 strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
198 default_bootup_tracer = bootup_tracer_buf;
199 /* We are using ftrace early, expand it */
200 trace_set_ring_buffer_expanded(NULL);
201 return 1;
202}
203__setup("ftrace=", set_cmdline_ftrace);
204
205static int __init set_ftrace_dump_on_oops(char *str)
206{
207 if (*str++ != '=' || !*str || !strcmp("1", str)) {
208 ftrace_dump_on_oops = DUMP_ALL;
209 return 1;
210 }
211
212 if (!strcmp("orig_cpu", str) || !strcmp("2", str)) {
213 ftrace_dump_on_oops = DUMP_ORIG;
214 return 1;
215 }
216
217 return 0;
218}
219__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
220
221static int __init stop_trace_on_warning(char *str)
222{
223 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
224 __disable_trace_on_warning = 1;
225 return 1;
226}
227__setup("traceoff_on_warning", stop_trace_on_warning);
228
229static int __init boot_alloc_snapshot(char *str)
230{
231 char *slot = boot_snapshot_info + boot_snapshot_index;
232 int left = sizeof(boot_snapshot_info) - boot_snapshot_index;
233 int ret;
234
235 if (str[0] == '=') {
236 str++;
237 if (strlen(str) >= left)
238 return -1;
239
240 ret = snprintf(slot, left, "%s\t", str);
241 boot_snapshot_index += ret;
242 } else {
243 allocate_snapshot = true;
244 /* We also need the main ring buffer expanded */
245 trace_set_ring_buffer_expanded(NULL);
246 }
247 return 1;
248}
249__setup("alloc_snapshot", boot_alloc_snapshot);
250
251
252static int __init boot_snapshot(char *str)
253{
254 snapshot_at_boot = true;
255 boot_alloc_snapshot(str);
256 return 1;
257}
258__setup("ftrace_boot_snapshot", boot_snapshot);
259
260
261static int __init boot_instance(char *str)
262{
263 char *slot = boot_instance_info + boot_instance_index;
264 int left = sizeof(boot_instance_info) - boot_instance_index;
265 int ret;
266
267 if (strlen(str) >= left)
268 return -1;
269
270 ret = snprintf(slot, left, "%s\t", str);
271 boot_instance_index += ret;
272
273 return 1;
274}
275__setup("trace_instance=", boot_instance);
276
277
278static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
279
280static int __init set_trace_boot_options(char *str)
281{
282 strscpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
283 return 1;
284}
285__setup("trace_options=", set_trace_boot_options);
286
287static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
288static char *trace_boot_clock __initdata;
289
290static int __init set_trace_boot_clock(char *str)
291{
292 strscpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
293 trace_boot_clock = trace_boot_clock_buf;
294 return 1;
295}
296__setup("trace_clock=", set_trace_boot_clock);
297
298static int __init set_tracepoint_printk(char *str)
299{
300 /* Ignore the "tp_printk_stop_on_boot" param */
301 if (*str == '_')
302 return 0;
303
304 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
305 tracepoint_printk = 1;
306 return 1;
307}
308__setup("tp_printk", set_tracepoint_printk);
309
310static int __init set_tracepoint_printk_stop(char *str)
311{
312 tracepoint_printk_stop_on_boot = true;
313 return 1;
314}
315__setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop);
316
317unsigned long long ns2usecs(u64 nsec)
318{
319 nsec += 500;
320 do_div(nsec, 1000);
321 return nsec;
322}
323
324static void
325trace_process_export(struct trace_export *export,
326 struct ring_buffer_event *event, int flag)
327{
328 struct trace_entry *entry;
329 unsigned int size = 0;
330
331 if (export->flags & flag) {
332 entry = ring_buffer_event_data(event);
333 size = ring_buffer_event_length(event);
334 export->write(export, entry, size);
335 }
336}
337
338static DEFINE_MUTEX(ftrace_export_lock);
339
340static struct trace_export __rcu *ftrace_exports_list __read_mostly;
341
342static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled);
343static DEFINE_STATIC_KEY_FALSE(trace_event_exports_enabled);
344static DEFINE_STATIC_KEY_FALSE(trace_marker_exports_enabled);
345
346static inline void ftrace_exports_enable(struct trace_export *export)
347{
348 if (export->flags & TRACE_EXPORT_FUNCTION)
349 static_branch_inc(&trace_function_exports_enabled);
350
351 if (export->flags & TRACE_EXPORT_EVENT)
352 static_branch_inc(&trace_event_exports_enabled);
353
354 if (export->flags & TRACE_EXPORT_MARKER)
355 static_branch_inc(&trace_marker_exports_enabled);
356}
357
358static inline void ftrace_exports_disable(struct trace_export *export)
359{
360 if (export->flags & TRACE_EXPORT_FUNCTION)
361 static_branch_dec(&trace_function_exports_enabled);
362
363 if (export->flags & TRACE_EXPORT_EVENT)
364 static_branch_dec(&trace_event_exports_enabled);
365
366 if (export->flags & TRACE_EXPORT_MARKER)
367 static_branch_dec(&trace_marker_exports_enabled);
368}
369
370static void ftrace_exports(struct ring_buffer_event *event, int flag)
371{
372 struct trace_export *export;
373
374 preempt_disable_notrace();
375
376 export = rcu_dereference_raw_check(ftrace_exports_list);
377 while (export) {
378 trace_process_export(export, event, flag);
379 export = rcu_dereference_raw_check(export->next);
380 }
381
382 preempt_enable_notrace();
383}
384
385static inline void
386add_trace_export(struct trace_export **list, struct trace_export *export)
387{
388 rcu_assign_pointer(export->next, *list);
389 /*
390 * We are entering export into the list but another
391 * CPU might be walking that list. We need to make sure
392 * the export->next pointer is valid before another CPU sees
393 * the export pointer included into the list.
394 */
395 rcu_assign_pointer(*list, export);
396}
397
398static inline int
399rm_trace_export(struct trace_export **list, struct trace_export *export)
400{
401 struct trace_export **p;
402
403 for (p = list; *p != NULL; p = &(*p)->next)
404 if (*p == export)
405 break;
406
407 if (*p != export)
408 return -1;
409
410 rcu_assign_pointer(*p, (*p)->next);
411
412 return 0;
413}
414
415static inline void
416add_ftrace_export(struct trace_export **list, struct trace_export *export)
417{
418 ftrace_exports_enable(export);
419
420 add_trace_export(list, export);
421}
422
423static inline int
424rm_ftrace_export(struct trace_export **list, struct trace_export *export)
425{
426 int ret;
427
428 ret = rm_trace_export(list, export);
429 ftrace_exports_disable(export);
430
431 return ret;
432}
433
434int register_ftrace_export(struct trace_export *export)
435{
436 if (WARN_ON_ONCE(!export->write))
437 return -1;
438
439 mutex_lock(&ftrace_export_lock);
440
441 add_ftrace_export(&ftrace_exports_list, export);
442
443 mutex_unlock(&ftrace_export_lock);
444
445 return 0;
446}
447EXPORT_SYMBOL_GPL(register_ftrace_export);
448
449int unregister_ftrace_export(struct trace_export *export)
450{
451 int ret;
452
453 mutex_lock(&ftrace_export_lock);
454
455 ret = rm_ftrace_export(&ftrace_exports_list, export);
456
457 mutex_unlock(&ftrace_export_lock);
458
459 return ret;
460}
461EXPORT_SYMBOL_GPL(unregister_ftrace_export);
462
463/* trace_flags holds trace_options default values */
464#define TRACE_DEFAULT_FLAGS \
465 (FUNCTION_DEFAULT_FLAGS | \
466 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
467 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
468 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
469 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | \
470 TRACE_ITER_HASH_PTR)
471
472/* trace_options that are only supported by global_trace */
473#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
474 TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
475
476/* trace_flags that are default zero for instances */
477#define ZEROED_TRACE_FLAGS \
478 (TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK)
479
480/*
481 * The global_trace is the descriptor that holds the top-level tracing
482 * buffers for the live tracing.
483 */
484static struct trace_array global_trace = {
485 .trace_flags = TRACE_DEFAULT_FLAGS,
486};
487
488void trace_set_ring_buffer_expanded(struct trace_array *tr)
489{
490 if (!tr)
491 tr = &global_trace;
492 tr->ring_buffer_expanded = true;
493}
494
495LIST_HEAD(ftrace_trace_arrays);
496
497int trace_array_get(struct trace_array *this_tr)
498{
499 struct trace_array *tr;
500 int ret = -ENODEV;
501
502 mutex_lock(&trace_types_lock);
503 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
504 if (tr == this_tr) {
505 tr->ref++;
506 ret = 0;
507 break;
508 }
509 }
510 mutex_unlock(&trace_types_lock);
511
512 return ret;
513}
514
515static void __trace_array_put(struct trace_array *this_tr)
516{
517 WARN_ON(!this_tr->ref);
518 this_tr->ref--;
519}
520
521/**
522 * trace_array_put - Decrement the reference counter for this trace array.
523 * @this_tr : pointer to the trace array
524 *
525 * NOTE: Use this when we no longer need the trace array returned by
526 * trace_array_get_by_name(). This ensures the trace array can be later
527 * destroyed.
528 *
529 */
530void trace_array_put(struct trace_array *this_tr)
531{
532 if (!this_tr)
533 return;
534
535 mutex_lock(&trace_types_lock);
536 __trace_array_put(this_tr);
537 mutex_unlock(&trace_types_lock);
538}
539EXPORT_SYMBOL_GPL(trace_array_put);
540
541int tracing_check_open_get_tr(struct trace_array *tr)
542{
543 int ret;
544
545 ret = security_locked_down(LOCKDOWN_TRACEFS);
546 if (ret)
547 return ret;
548
549 if (tracing_disabled)
550 return -ENODEV;
551
552 if (tr && trace_array_get(tr) < 0)
553 return -ENODEV;
554
555 return 0;
556}
557
558int call_filter_check_discard(struct trace_event_call *call, void *rec,
559 struct trace_buffer *buffer,
560 struct ring_buffer_event *event)
561{
562 if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
563 !filter_match_preds(call->filter, rec)) {
564 __trace_event_discard_commit(buffer, event);
565 return 1;
566 }
567
568 return 0;
569}
570
571/**
572 * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
573 * @filtered_pids: The list of pids to check
574 * @search_pid: The PID to find in @filtered_pids
575 *
576 * Returns true if @search_pid is found in @filtered_pids, and false otherwise.
577 */
578bool
579trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
580{
581 return trace_pid_list_is_set(filtered_pids, search_pid);
582}
583
584/**
585 * trace_ignore_this_task - should a task be ignored for tracing
586 * @filtered_pids: The list of pids to check
587 * @filtered_no_pids: The list of pids not to be traced
588 * @task: The task that should be ignored if not filtered
589 *
590 * Checks if @task should be traced or not from @filtered_pids.
591 * Returns true if @task should *NOT* be traced.
592 * Returns false if @task should be traced.
593 */
594bool
595trace_ignore_this_task(struct trace_pid_list *filtered_pids,
596 struct trace_pid_list *filtered_no_pids,
597 struct task_struct *task)
598{
599 /*
600 * If filtered_no_pids is not empty, and the task's pid is listed
601 * in filtered_no_pids, then return true.
602 * Otherwise, if filtered_pids is empty, that means we can
603 * trace all tasks. If it has content, then only trace pids
604 * within filtered_pids.
605 */
606
607 return (filtered_pids &&
608 !trace_find_filtered_pid(filtered_pids, task->pid)) ||
609 (filtered_no_pids &&
610 trace_find_filtered_pid(filtered_no_pids, task->pid));
611}
612
613/**
614 * trace_filter_add_remove_task - Add or remove a task from a pid_list
615 * @pid_list: The list to modify
616 * @self: The current task for fork or NULL for exit
617 * @task: The task to add or remove
618 *
619 * If adding a task, if @self is defined, the task is only added if @self
620 * is also included in @pid_list. This happens on fork and tasks should
621 * only be added when the parent is listed. If @self is NULL, then the
622 * @task pid will be removed from the list, which would happen on exit
623 * of a task.
624 */
625void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
626 struct task_struct *self,
627 struct task_struct *task)
628{
629 if (!pid_list)
630 return;
631
632 /* For forks, we only add if the forking task is listed */
633 if (self) {
634 if (!trace_find_filtered_pid(pid_list, self->pid))
635 return;
636 }
637
638 /* "self" is set for forks, and NULL for exits */
639 if (self)
640 trace_pid_list_set(pid_list, task->pid);
641 else
642 trace_pid_list_clear(pid_list, task->pid);
643}
644
645/**
646 * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
647 * @pid_list: The pid list to show
648 * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
649 * @pos: The position of the file
650 *
651 * This is used by the seq_file "next" operation to iterate the pids
652 * listed in a trace_pid_list structure.
653 *
654 * Returns the pid+1 as we want to display pid of zero, but NULL would
655 * stop the iteration.
656 */
657void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
658{
659 long pid = (unsigned long)v;
660 unsigned int next;
661
662 (*pos)++;
663
664 /* pid already is +1 of the actual previous bit */
665 if (trace_pid_list_next(pid_list, pid, &next) < 0)
666 return NULL;
667
668 pid = next;
669
670 /* Return pid + 1 to allow zero to be represented */
671 return (void *)(pid + 1);
672}
673
674/**
675 * trace_pid_start - Used for seq_file to start reading pid lists
676 * @pid_list: The pid list to show
677 * @pos: The position of the file
678 *
679 * This is used by seq_file "start" operation to start the iteration
680 * of listing pids.
681 *
682 * Returns the pid+1 as we want to display pid of zero, but NULL would
683 * stop the iteration.
684 */
685void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
686{
687 unsigned long pid;
688 unsigned int first;
689 loff_t l = 0;
690
691 if (trace_pid_list_first(pid_list, &first) < 0)
692 return NULL;
693
694 pid = first;
695
696 /* Return pid + 1 so that zero can be the exit value */
697 for (pid++; pid && l < *pos;
698 pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
699 ;
700 return (void *)pid;
701}
702
703/**
704 * trace_pid_show - show the current pid in seq_file processing
705 * @m: The seq_file structure to write into
706 * @v: A void pointer of the pid (+1) value to display
707 *
708 * Can be directly used by seq_file operations to display the current
709 * pid value.
710 */
711int trace_pid_show(struct seq_file *m, void *v)
712{
713 unsigned long pid = (unsigned long)v - 1;
714
715 seq_printf(m, "%lu\n", pid);
716 return 0;
717}
718
719/* 128 should be much more than enough */
720#define PID_BUF_SIZE 127
721
722int trace_pid_write(struct trace_pid_list *filtered_pids,
723 struct trace_pid_list **new_pid_list,
724 const char __user *ubuf, size_t cnt)
725{
726 struct trace_pid_list *pid_list;
727 struct trace_parser parser;
728 unsigned long val;
729 int nr_pids = 0;
730 ssize_t read = 0;
731 ssize_t ret;
732 loff_t pos;
733 pid_t pid;
734
735 if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
736 return -ENOMEM;
737
738 /*
739 * Always recreate a new array. The write is an all or nothing
740 * operation. Always create a new array when adding new pids by
741 * the user. If the operation fails, then the current list is
742 * not modified.
743 */
744 pid_list = trace_pid_list_alloc();
745 if (!pid_list) {
746 trace_parser_put(&parser);
747 return -ENOMEM;
748 }
749
750 if (filtered_pids) {
751 /* copy the current bits to the new max */
752 ret = trace_pid_list_first(filtered_pids, &pid);
753 while (!ret) {
754 trace_pid_list_set(pid_list, pid);
755 ret = trace_pid_list_next(filtered_pids, pid + 1, &pid);
756 nr_pids++;
757 }
758 }
759
760 ret = 0;
761 while (cnt > 0) {
762
763 pos = 0;
764
765 ret = trace_get_user(&parser, ubuf, cnt, &pos);
766 if (ret < 0)
767 break;
768
769 read += ret;
770 ubuf += ret;
771 cnt -= ret;
772
773 if (!trace_parser_loaded(&parser))
774 break;
775
776 ret = -EINVAL;
777 if (kstrtoul(parser.buffer, 0, &val))
778 break;
779
780 pid = (pid_t)val;
781
782 if (trace_pid_list_set(pid_list, pid) < 0) {
783 ret = -1;
784 break;
785 }
786 nr_pids++;
787
788 trace_parser_clear(&parser);
789 ret = 0;
790 }
791 trace_parser_put(&parser);
792
793 if (ret < 0) {
794 trace_pid_list_free(pid_list);
795 return ret;
796 }
797
798 if (!nr_pids) {
799 /* Cleared the list of pids */
800 trace_pid_list_free(pid_list);
801 pid_list = NULL;
802 }
803
804 *new_pid_list = pid_list;
805
806 return read;
807}
808
809static u64 buffer_ftrace_now(struct array_buffer *buf, int cpu)
810{
811 u64 ts;
812
813 /* Early boot up does not have a buffer yet */
814 if (!buf->buffer)
815 return trace_clock_local();
816
817 ts = ring_buffer_time_stamp(buf->buffer);
818 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
819
820 return ts;
821}
822
823u64 ftrace_now(int cpu)
824{
825 return buffer_ftrace_now(&global_trace.array_buffer, cpu);
826}
827
828/**
829 * tracing_is_enabled - Show if global_trace has been enabled
830 *
831 * Shows if the global trace has been enabled or not. It uses the
832 * mirror flag "buffer_disabled" to be used in fast paths such as for
833 * the irqsoff tracer. But it may be inaccurate due to races. If you
834 * need to know the accurate state, use tracing_is_on() which is a little
835 * slower, but accurate.
836 */
837int tracing_is_enabled(void)
838{
839 /*
840 * For quick access (irqsoff uses this in fast path), just
841 * return the mirror variable of the state of the ring buffer.
842 * It's a little racy, but we don't really care.
843 */
844 smp_rmb();
845 return !global_trace.buffer_disabled;
846}
847
848/*
849 * trace_buf_size is the size in bytes that is allocated
850 * for a buffer. Note, the number of bytes is always rounded
851 * to page size.
852 *
853 * This number is purposely set to a low number of 16384.
854 * If the dump on oops happens, it will be much appreciated
855 * to not have to wait for all that output. Anyway this can be
856 * boot time and run time configurable.
857 */
858#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
859
860static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
861
862/* trace_types holds a link list of available tracers. */
863static struct tracer *trace_types __read_mostly;
864
865/*
866 * trace_types_lock is used to protect the trace_types list.
867 */
868DEFINE_MUTEX(trace_types_lock);
869
870/*
871 * serialize the access of the ring buffer
872 *
873 * ring buffer serializes readers, but it is low level protection.
874 * The validity of the events (which returns by ring_buffer_peek() ..etc)
875 * are not protected by ring buffer.
876 *
877 * The content of events may become garbage if we allow other process consumes
878 * these events concurrently:
879 * A) the page of the consumed events may become a normal page
880 * (not reader page) in ring buffer, and this page will be rewritten
881 * by events producer.
882 * B) The page of the consumed events may become a page for splice_read,
883 * and this page will be returned to system.
884 *
885 * These primitives allow multi process access to different cpu ring buffer
886 * concurrently.
887 *
888 * These primitives don't distinguish read-only and read-consume access.
889 * Multi read-only access are also serialized.
890 */
891
892#ifdef CONFIG_SMP
893static DECLARE_RWSEM(all_cpu_access_lock);
894static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
895
896static inline void trace_access_lock(int cpu)
897{
898 if (cpu == RING_BUFFER_ALL_CPUS) {
899 /* gain it for accessing the whole ring buffer. */
900 down_write(&all_cpu_access_lock);
901 } else {
902 /* gain it for accessing a cpu ring buffer. */
903
904 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
905 down_read(&all_cpu_access_lock);
906
907 /* Secondly block other access to this @cpu ring buffer. */
908 mutex_lock(&per_cpu(cpu_access_lock, cpu));
909 }
910}
911
912static inline void trace_access_unlock(int cpu)
913{
914 if (cpu == RING_BUFFER_ALL_CPUS) {
915 up_write(&all_cpu_access_lock);
916 } else {
917 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
918 up_read(&all_cpu_access_lock);
919 }
920}
921
922static inline void trace_access_lock_init(void)
923{
924 int cpu;
925
926 for_each_possible_cpu(cpu)
927 mutex_init(&per_cpu(cpu_access_lock, cpu));
928}
929
930#else
931
932static DEFINE_MUTEX(access_lock);
933
934static inline void trace_access_lock(int cpu)
935{
936 (void)cpu;
937 mutex_lock(&access_lock);
938}
939
940static inline void trace_access_unlock(int cpu)
941{
942 (void)cpu;
943 mutex_unlock(&access_lock);
944}
945
946static inline void trace_access_lock_init(void)
947{
948}
949
950#endif
951
952#ifdef CONFIG_STACKTRACE
953static void __ftrace_trace_stack(struct trace_buffer *buffer,
954 unsigned int trace_ctx,
955 int skip, struct pt_regs *regs);
956static inline void ftrace_trace_stack(struct trace_array *tr,
957 struct trace_buffer *buffer,
958 unsigned int trace_ctx,
959 int skip, struct pt_regs *regs);
960
961#else
962static inline void __ftrace_trace_stack(struct trace_buffer *buffer,
963 unsigned int trace_ctx,
964 int skip, struct pt_regs *regs)
965{
966}
967static inline void ftrace_trace_stack(struct trace_array *tr,
968 struct trace_buffer *buffer,
969 unsigned long trace_ctx,
970 int skip, struct pt_regs *regs)
971{
972}
973
974#endif
975
976static __always_inline void
977trace_event_setup(struct ring_buffer_event *event,
978 int type, unsigned int trace_ctx)
979{
980 struct trace_entry *ent = ring_buffer_event_data(event);
981
982 tracing_generic_entry_update(ent, type, trace_ctx);
983}
984
985static __always_inline struct ring_buffer_event *
986__trace_buffer_lock_reserve(struct trace_buffer *buffer,
987 int type,
988 unsigned long len,
989 unsigned int trace_ctx)
990{
991 struct ring_buffer_event *event;
992
993 event = ring_buffer_lock_reserve(buffer, len);
994 if (event != NULL)
995 trace_event_setup(event, type, trace_ctx);
996
997 return event;
998}
999
1000void tracer_tracing_on(struct trace_array *tr)
1001{
1002 if (tr->array_buffer.buffer)
1003 ring_buffer_record_on(tr->array_buffer.buffer);
1004 /*
1005 * This flag is looked at when buffers haven't been allocated
1006 * yet, or by some tracers (like irqsoff), that just want to
1007 * know if the ring buffer has been disabled, but it can handle
1008 * races of where it gets disabled but we still do a record.
1009 * As the check is in the fast path of the tracers, it is more
1010 * important to be fast than accurate.
1011 */
1012 tr->buffer_disabled = 0;
1013 /* Make the flag seen by readers */
1014 smp_wmb();
1015}
1016
1017/**
1018 * tracing_on - enable tracing buffers
1019 *
1020 * This function enables tracing buffers that may have been
1021 * disabled with tracing_off.
1022 */
1023void tracing_on(void)
1024{
1025 tracer_tracing_on(&global_trace);
1026}
1027EXPORT_SYMBOL_GPL(tracing_on);
1028
1029
1030static __always_inline void
1031__buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *event)
1032{
1033 __this_cpu_write(trace_taskinfo_save, true);
1034
1035 /* If this is the temp buffer, we need to commit fully */
1036 if (this_cpu_read(trace_buffered_event) == event) {
1037 /* Length is in event->array[0] */
1038 ring_buffer_write(buffer, event->array[0], &event->array[1]);
1039 /* Release the temp buffer */
1040 this_cpu_dec(trace_buffered_event_cnt);
1041 /* ring_buffer_unlock_commit() enables preemption */
1042 preempt_enable_notrace();
1043 } else
1044 ring_buffer_unlock_commit(buffer);
1045}
1046
1047int __trace_array_puts(struct trace_array *tr, unsigned long ip,
1048 const char *str, int size)
1049{
1050 struct ring_buffer_event *event;
1051 struct trace_buffer *buffer;
1052 struct print_entry *entry;
1053 unsigned int trace_ctx;
1054 int alloc;
1055
1056 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
1057 return 0;
1058
1059 if (unlikely(tracing_selftest_running && tr == &global_trace))
1060 return 0;
1061
1062 if (unlikely(tracing_disabled))
1063 return 0;
1064
1065 alloc = sizeof(*entry) + size + 2; /* possible \n added */
1066
1067 trace_ctx = tracing_gen_ctx();
1068 buffer = tr->array_buffer.buffer;
1069 ring_buffer_nest_start(buffer);
1070 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
1071 trace_ctx);
1072 if (!event) {
1073 size = 0;
1074 goto out;
1075 }
1076
1077 entry = ring_buffer_event_data(event);
1078 entry->ip = ip;
1079
1080 memcpy(&entry->buf, str, size);
1081
1082 /* Add a newline if necessary */
1083 if (entry->buf[size - 1] != '\n') {
1084 entry->buf[size] = '\n';
1085 entry->buf[size + 1] = '\0';
1086 } else
1087 entry->buf[size] = '\0';
1088
1089 __buffer_unlock_commit(buffer, event);
1090 ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
1091 out:
1092 ring_buffer_nest_end(buffer);
1093 return size;
1094}
1095EXPORT_SYMBOL_GPL(__trace_array_puts);
1096
1097/**
1098 * __trace_puts - write a constant string into the trace buffer.
1099 * @ip: The address of the caller
1100 * @str: The constant string to write
1101 * @size: The size of the string.
1102 */
1103int __trace_puts(unsigned long ip, const char *str, int size)
1104{
1105 return __trace_array_puts(&global_trace, ip, str, size);
1106}
1107EXPORT_SYMBOL_GPL(__trace_puts);
1108
1109/**
1110 * __trace_bputs - write the pointer to a constant string into trace buffer
1111 * @ip: The address of the caller
1112 * @str: The constant string to write to the buffer to
1113 */
1114int __trace_bputs(unsigned long ip, const char *str)
1115{
1116 struct ring_buffer_event *event;
1117 struct trace_buffer *buffer;
1118 struct bputs_entry *entry;
1119 unsigned int trace_ctx;
1120 int size = sizeof(struct bputs_entry);
1121 int ret = 0;
1122
1123 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
1124 return 0;
1125
1126 if (unlikely(tracing_selftest_running || tracing_disabled))
1127 return 0;
1128
1129 trace_ctx = tracing_gen_ctx();
1130 buffer = global_trace.array_buffer.buffer;
1131
1132 ring_buffer_nest_start(buffer);
1133 event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
1134 trace_ctx);
1135 if (!event)
1136 goto out;
1137
1138 entry = ring_buffer_event_data(event);
1139 entry->ip = ip;
1140 entry->str = str;
1141
1142 __buffer_unlock_commit(buffer, event);
1143 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
1144
1145 ret = 1;
1146 out:
1147 ring_buffer_nest_end(buffer);
1148 return ret;
1149}
1150EXPORT_SYMBOL_GPL(__trace_bputs);
1151
1152#ifdef CONFIG_TRACER_SNAPSHOT
1153static void tracing_snapshot_instance_cond(struct trace_array *tr,
1154 void *cond_data)
1155{
1156 struct tracer *tracer = tr->current_trace;
1157 unsigned long flags;
1158
1159 if (in_nmi()) {
1160 trace_array_puts(tr, "*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
1161 trace_array_puts(tr, "*** snapshot is being ignored ***\n");
1162 return;
1163 }
1164
1165 if (!tr->allocated_snapshot) {
1166 trace_array_puts(tr, "*** SNAPSHOT NOT ALLOCATED ***\n");
1167 trace_array_puts(tr, "*** stopping trace here! ***\n");
1168 tracer_tracing_off(tr);
1169 return;
1170 }
1171
1172 /* Note, snapshot can not be used when the tracer uses it */
1173 if (tracer->use_max_tr) {
1174 trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n");
1175 trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
1176 return;
1177 }
1178
1179 local_irq_save(flags);
1180 update_max_tr(tr, current, smp_processor_id(), cond_data);
1181 local_irq_restore(flags);
1182}
1183
1184void tracing_snapshot_instance(struct trace_array *tr)
1185{
1186 tracing_snapshot_instance_cond(tr, NULL);
1187}
1188
1189/**
1190 * tracing_snapshot - take a snapshot of the current buffer.
1191 *
1192 * This causes a swap between the snapshot buffer and the current live
1193 * tracing buffer. You can use this to take snapshots of the live
1194 * trace when some condition is triggered, but continue to trace.
1195 *
1196 * Note, make sure to allocate the snapshot with either
1197 * a tracing_snapshot_alloc(), or by doing it manually
1198 * with: echo 1 > /sys/kernel/tracing/snapshot
1199 *
1200 * If the snapshot buffer is not allocated, it will stop tracing.
1201 * Basically making a permanent snapshot.
1202 */
1203void tracing_snapshot(void)
1204{
1205 struct trace_array *tr = &global_trace;
1206
1207 tracing_snapshot_instance(tr);
1208}
1209EXPORT_SYMBOL_GPL(tracing_snapshot);
1210
1211/**
1212 * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
1213 * @tr: The tracing instance to snapshot
1214 * @cond_data: The data to be tested conditionally, and possibly saved
1215 *
1216 * This is the same as tracing_snapshot() except that the snapshot is
1217 * conditional - the snapshot will only happen if the
1218 * cond_snapshot.update() implementation receiving the cond_data
1219 * returns true, which means that the trace array's cond_snapshot
1220 * update() operation used the cond_data to determine whether the
1221 * snapshot should be taken, and if it was, presumably saved it along
1222 * with the snapshot.
1223 */
1224void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1225{
1226 tracing_snapshot_instance_cond(tr, cond_data);
1227}
1228EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1229
1230/**
1231 * tracing_cond_snapshot_data - get the user data associated with a snapshot
1232 * @tr: The tracing instance
1233 *
1234 * When the user enables a conditional snapshot using
1235 * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
1236 * with the snapshot. This accessor is used to retrieve it.
1237 *
1238 * Should not be called from cond_snapshot.update(), since it takes
1239 * the tr->max_lock lock, which the code calling
1240 * cond_snapshot.update() has already done.
1241 *
1242 * Returns the cond_data associated with the trace array's snapshot.
1243 */
1244void *tracing_cond_snapshot_data(struct trace_array *tr)
1245{
1246 void *cond_data = NULL;
1247
1248 local_irq_disable();
1249 arch_spin_lock(&tr->max_lock);
1250
1251 if (tr->cond_snapshot)
1252 cond_data = tr->cond_snapshot->cond_data;
1253
1254 arch_spin_unlock(&tr->max_lock);
1255 local_irq_enable();
1256
1257 return cond_data;
1258}
1259EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1260
1261static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
1262 struct array_buffer *size_buf, int cpu_id);
1263static void set_buffer_entries(struct array_buffer *buf, unsigned long val);
1264
1265int tracing_alloc_snapshot_instance(struct trace_array *tr)
1266{
1267 int order;
1268 int ret;
1269
1270 if (!tr->allocated_snapshot) {
1271
1272 /* Make the snapshot buffer have the same order as main buffer */
1273 order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
1274 ret = ring_buffer_subbuf_order_set(tr->max_buffer.buffer, order);
1275 if (ret < 0)
1276 return ret;
1277
1278 /* allocate spare buffer */
1279 ret = resize_buffer_duplicate_size(&tr->max_buffer,
1280 &tr->array_buffer, RING_BUFFER_ALL_CPUS);
1281 if (ret < 0)
1282 return ret;
1283
1284 tr->allocated_snapshot = true;
1285 }
1286
1287 return 0;
1288}
1289
1290static void free_snapshot(struct trace_array *tr)
1291{
1292 /*
1293 * We don't free the ring buffer. instead, resize it because
1294 * The max_tr ring buffer has some state (e.g. ring->clock) and
1295 * we want preserve it.
1296 */
1297 ring_buffer_subbuf_order_set(tr->max_buffer.buffer, 0);
1298 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
1299 set_buffer_entries(&tr->max_buffer, 1);
1300 tracing_reset_online_cpus(&tr->max_buffer);
1301 tr->allocated_snapshot = false;
1302}
1303
1304/**
1305 * tracing_alloc_snapshot - allocate snapshot buffer.
1306 *
1307 * This only allocates the snapshot buffer if it isn't already
1308 * allocated - it doesn't also take a snapshot.
1309 *
1310 * This is meant to be used in cases where the snapshot buffer needs
1311 * to be set up for events that can't sleep but need to be able to
1312 * trigger a snapshot.
1313 */
1314int tracing_alloc_snapshot(void)
1315{
1316 struct trace_array *tr = &global_trace;
1317 int ret;
1318
1319 ret = tracing_alloc_snapshot_instance(tr);
1320 WARN_ON(ret < 0);
1321
1322 return ret;
1323}
1324EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1325
1326/**
1327 * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
1328 *
1329 * This is similar to tracing_snapshot(), but it will allocate the
1330 * snapshot buffer if it isn't already allocated. Use this only
1331 * where it is safe to sleep, as the allocation may sleep.
1332 *
1333 * This causes a swap between the snapshot buffer and the current live
1334 * tracing buffer. You can use this to take snapshots of the live
1335 * trace when some condition is triggered, but continue to trace.
1336 */
1337void tracing_snapshot_alloc(void)
1338{
1339 int ret;
1340
1341 ret = tracing_alloc_snapshot();
1342 if (ret < 0)
1343 return;
1344
1345 tracing_snapshot();
1346}
1347EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1348
1349/**
1350 * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
1351 * @tr: The tracing instance
1352 * @cond_data: User data to associate with the snapshot
1353 * @update: Implementation of the cond_snapshot update function
1354 *
1355 * Check whether the conditional snapshot for the given instance has
1356 * already been enabled, or if the current tracer is already using a
1357 * snapshot; if so, return -EBUSY, else create a cond_snapshot and
1358 * save the cond_data and update function inside.
1359 *
1360 * Returns 0 if successful, error otherwise.
1361 */
1362int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
1363 cond_update_fn_t update)
1364{
1365 struct cond_snapshot *cond_snapshot;
1366 int ret = 0;
1367
1368 cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
1369 if (!cond_snapshot)
1370 return -ENOMEM;
1371
1372 cond_snapshot->cond_data = cond_data;
1373 cond_snapshot->update = update;
1374
1375 mutex_lock(&trace_types_lock);
1376
1377 ret = tracing_alloc_snapshot_instance(tr);
1378 if (ret)
1379 goto fail_unlock;
1380
1381 if (tr->current_trace->use_max_tr) {
1382 ret = -EBUSY;
1383 goto fail_unlock;
1384 }
1385
1386 /*
1387 * The cond_snapshot can only change to NULL without the
1388 * trace_types_lock. We don't care if we race with it going
1389 * to NULL, but we want to make sure that it's not set to
1390 * something other than NULL when we get here, which we can
1391 * do safely with only holding the trace_types_lock and not
1392 * having to take the max_lock.
1393 */
1394 if (tr->cond_snapshot) {
1395 ret = -EBUSY;
1396 goto fail_unlock;
1397 }
1398
1399 local_irq_disable();
1400 arch_spin_lock(&tr->max_lock);
1401 tr->cond_snapshot = cond_snapshot;
1402 arch_spin_unlock(&tr->max_lock);
1403 local_irq_enable();
1404
1405 mutex_unlock(&trace_types_lock);
1406
1407 return ret;
1408
1409 fail_unlock:
1410 mutex_unlock(&trace_types_lock);
1411 kfree(cond_snapshot);
1412 return ret;
1413}
1414EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1415
1416/**
1417 * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
1418 * @tr: The tracing instance
1419 *
1420 * Check whether the conditional snapshot for the given instance is
1421 * enabled; if so, free the cond_snapshot associated with it,
1422 * otherwise return -EINVAL.
1423 *
1424 * Returns 0 if successful, error otherwise.
1425 */
1426int tracing_snapshot_cond_disable(struct trace_array *tr)
1427{
1428 int ret = 0;
1429
1430 local_irq_disable();
1431 arch_spin_lock(&tr->max_lock);
1432
1433 if (!tr->cond_snapshot)
1434 ret = -EINVAL;
1435 else {
1436 kfree(tr->cond_snapshot);
1437 tr->cond_snapshot = NULL;
1438 }
1439
1440 arch_spin_unlock(&tr->max_lock);
1441 local_irq_enable();
1442
1443 return ret;
1444}
1445EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1446#else
1447void tracing_snapshot(void)
1448{
1449 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
1450}
1451EXPORT_SYMBOL_GPL(tracing_snapshot);
1452void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1453{
1454 WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
1455}
1456EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1457int tracing_alloc_snapshot(void)
1458{
1459 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
1460 return -ENODEV;
1461}
1462EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1463void tracing_snapshot_alloc(void)
1464{
1465 /* Give warning */
1466 tracing_snapshot();
1467}
1468EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1469void *tracing_cond_snapshot_data(struct trace_array *tr)
1470{
1471 return NULL;
1472}
1473EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1474int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
1475{
1476 return -ENODEV;
1477}
1478EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1479int tracing_snapshot_cond_disable(struct trace_array *tr)
1480{
1481 return false;
1482}
1483EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1484#define free_snapshot(tr) do { } while (0)
1485#endif /* CONFIG_TRACER_SNAPSHOT */
1486
1487void tracer_tracing_off(struct trace_array *tr)
1488{
1489 if (tr->array_buffer.buffer)
1490 ring_buffer_record_off(tr->array_buffer.buffer);
1491 /*
1492 * This flag is looked at when buffers haven't been allocated
1493 * yet, or by some tracers (like irqsoff), that just want to
1494 * know if the ring buffer has been disabled, but it can handle
1495 * races of where it gets disabled but we still do a record.
1496 * As the check is in the fast path of the tracers, it is more
1497 * important to be fast than accurate.
1498 */
1499 tr->buffer_disabled = 1;
1500 /* Make the flag seen by readers */
1501 smp_wmb();
1502}
1503
1504/**
1505 * tracing_off - turn off tracing buffers
1506 *
1507 * This function stops the tracing buffers from recording data.
1508 * It does not disable any overhead the tracers themselves may
1509 * be causing. This function simply causes all recording to
1510 * the ring buffers to fail.
1511 */
1512void tracing_off(void)
1513{
1514 tracer_tracing_off(&global_trace);
1515}
1516EXPORT_SYMBOL_GPL(tracing_off);
1517
1518void disable_trace_on_warning(void)
1519{
1520 if (__disable_trace_on_warning) {
1521 trace_array_printk_buf(global_trace.array_buffer.buffer, _THIS_IP_,
1522 "Disabling tracing due to warning\n");
1523 tracing_off();
1524 }
1525}
1526
1527/**
1528 * tracer_tracing_is_on - show real state of ring buffer enabled
1529 * @tr : the trace array to know if ring buffer is enabled
1530 *
1531 * Shows real state of the ring buffer if it is enabled or not.
1532 */
1533bool tracer_tracing_is_on(struct trace_array *tr)
1534{
1535 if (tr->array_buffer.buffer)
1536 return ring_buffer_record_is_set_on(tr->array_buffer.buffer);
1537 return !tr->buffer_disabled;
1538}
1539
1540/**
1541 * tracing_is_on - show state of ring buffers enabled
1542 */
1543int tracing_is_on(void)
1544{
1545 return tracer_tracing_is_on(&global_trace);
1546}
1547EXPORT_SYMBOL_GPL(tracing_is_on);
1548
1549static int __init set_buf_size(char *str)
1550{
1551 unsigned long buf_size;
1552
1553 if (!str)
1554 return 0;
1555 buf_size = memparse(str, &str);
1556 /*
1557 * nr_entries can not be zero and the startup
1558 * tests require some buffer space. Therefore
1559 * ensure we have at least 4096 bytes of buffer.
1560 */
1561 trace_buf_size = max(4096UL, buf_size);
1562 return 1;
1563}
1564__setup("trace_buf_size=", set_buf_size);
1565
1566static int __init set_tracing_thresh(char *str)
1567{
1568 unsigned long threshold;
1569 int ret;
1570
1571 if (!str)
1572 return 0;
1573 ret = kstrtoul(str, 0, &threshold);
1574 if (ret < 0)
1575 return 0;
1576 tracing_thresh = threshold * 1000;
1577 return 1;
1578}
1579__setup("tracing_thresh=", set_tracing_thresh);
1580
1581unsigned long nsecs_to_usecs(unsigned long nsecs)
1582{
1583 return nsecs / 1000;
1584}
1585
1586/*
1587 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
1588 * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
1589 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
1590 * of strings in the order that the evals (enum) were defined.
1591 */
1592#undef C
1593#define C(a, b) b
1594
1595/* These must match the bit positions in trace_iterator_flags */
1596static const char *trace_options[] = {
1597 TRACE_FLAGS
1598 NULL
1599};
1600
1601static struct {
1602 u64 (*func)(void);
1603 const char *name;
1604 int in_ns; /* is this clock in nanoseconds? */
1605} trace_clocks[] = {
1606 { trace_clock_local, "local", 1 },
1607 { trace_clock_global, "global", 1 },
1608 { trace_clock_counter, "counter", 0 },
1609 { trace_clock_jiffies, "uptime", 0 },
1610 { trace_clock, "perf", 1 },
1611 { ktime_get_mono_fast_ns, "mono", 1 },
1612 { ktime_get_raw_fast_ns, "mono_raw", 1 },
1613 { ktime_get_boot_fast_ns, "boot", 1 },
1614 { ktime_get_tai_fast_ns, "tai", 1 },
1615 ARCH_TRACE_CLOCKS
1616};
1617
1618bool trace_clock_in_ns(struct trace_array *tr)
1619{
1620 if (trace_clocks[tr->clock_id].in_ns)
1621 return true;
1622
1623 return false;
1624}
1625
1626/*
1627 * trace_parser_get_init - gets the buffer for trace parser
1628 */
1629int trace_parser_get_init(struct trace_parser *parser, int size)
1630{
1631 memset(parser, 0, sizeof(*parser));
1632
1633 parser->buffer = kmalloc(size, GFP_KERNEL);
1634 if (!parser->buffer)
1635 return 1;
1636
1637 parser->size = size;
1638 return 0;
1639}
1640
1641/*
1642 * trace_parser_put - frees the buffer for trace parser
1643 */
1644void trace_parser_put(struct trace_parser *parser)
1645{
1646 kfree(parser->buffer);
1647 parser->buffer = NULL;
1648}
1649
1650/*
1651 * trace_get_user - reads the user input string separated by space
1652 * (matched by isspace(ch))
1653 *
1654 * For each string found the 'struct trace_parser' is updated,
1655 * and the function returns.
1656 *
1657 * Returns number of bytes read.
1658 *
1659 * See kernel/trace/trace.h for 'struct trace_parser' details.
1660 */
1661int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1662 size_t cnt, loff_t *ppos)
1663{
1664 char ch;
1665 size_t read = 0;
1666 ssize_t ret;
1667
1668 if (!*ppos)
1669 trace_parser_clear(parser);
1670
1671 ret = get_user(ch, ubuf++);
1672 if (ret)
1673 goto out;
1674
1675 read++;
1676 cnt--;
1677
1678 /*
1679 * The parser is not finished with the last write,
1680 * continue reading the user input without skipping spaces.
1681 */
1682 if (!parser->cont) {
1683 /* skip white space */
1684 while (cnt && isspace(ch)) {
1685 ret = get_user(ch, ubuf++);
1686 if (ret)
1687 goto out;
1688 read++;
1689 cnt--;
1690 }
1691
1692 parser->idx = 0;
1693
1694 /* only spaces were written */
1695 if (isspace(ch) || !ch) {
1696 *ppos += read;
1697 ret = read;
1698 goto out;
1699 }
1700 }
1701
1702 /* read the non-space input */
1703 while (cnt && !isspace(ch) && ch) {
1704 if (parser->idx < parser->size - 1)
1705 parser->buffer[parser->idx++] = ch;
1706 else {
1707 ret = -EINVAL;
1708 goto out;
1709 }
1710 ret = get_user(ch, ubuf++);
1711 if (ret)
1712 goto out;
1713 read++;
1714 cnt--;
1715 }
1716
1717 /* We either got finished input or we have to wait for another call. */
1718 if (isspace(ch) || !ch) {
1719 parser->buffer[parser->idx] = 0;
1720 parser->cont = false;
1721 } else if (parser->idx < parser->size - 1) {
1722 parser->cont = true;
1723 parser->buffer[parser->idx++] = ch;
1724 /* Make sure the parsed string always terminates with '\0'. */
1725 parser->buffer[parser->idx] = 0;
1726 } else {
1727 ret = -EINVAL;
1728 goto out;
1729 }
1730
1731 *ppos += read;
1732 ret = read;
1733
1734out:
1735 return ret;
1736}
1737
1738/* TODO add a seq_buf_to_buffer() */
1739static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1740{
1741 int len;
1742
1743 if (trace_seq_used(s) <= s->readpos)
1744 return -EBUSY;
1745
1746 len = trace_seq_used(s) - s->readpos;
1747 if (cnt > len)
1748 cnt = len;
1749 memcpy(buf, s->buffer + s->readpos, cnt);
1750
1751 s->readpos += cnt;
1752 return cnt;
1753}
1754
1755unsigned long __read_mostly tracing_thresh;
1756
1757#ifdef CONFIG_TRACER_MAX_TRACE
1758static const struct file_operations tracing_max_lat_fops;
1759
1760#ifdef LATENCY_FS_NOTIFY
1761
1762static struct workqueue_struct *fsnotify_wq;
1763
1764static void latency_fsnotify_workfn(struct work_struct *work)
1765{
1766 struct trace_array *tr = container_of(work, struct trace_array,
1767 fsnotify_work);
1768 fsnotify_inode(tr->d_max_latency->d_inode, FS_MODIFY);
1769}
1770
1771static void latency_fsnotify_workfn_irq(struct irq_work *iwork)
1772{
1773 struct trace_array *tr = container_of(iwork, struct trace_array,
1774 fsnotify_irqwork);
1775 queue_work(fsnotify_wq, &tr->fsnotify_work);
1776}
1777
1778static void trace_create_maxlat_file(struct trace_array *tr,
1779 struct dentry *d_tracer)
1780{
1781 INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
1782 init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
1783 tr->d_max_latency = trace_create_file("tracing_max_latency",
1784 TRACE_MODE_WRITE,
1785 d_tracer, tr,
1786 &tracing_max_lat_fops);
1787}
1788
1789__init static int latency_fsnotify_init(void)
1790{
1791 fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
1792 WQ_UNBOUND | WQ_HIGHPRI, 0);
1793 if (!fsnotify_wq) {
1794 pr_err("Unable to allocate tr_max_lat_wq\n");
1795 return -ENOMEM;
1796 }
1797 return 0;
1798}
1799
1800late_initcall_sync(latency_fsnotify_init);
1801
1802void latency_fsnotify(struct trace_array *tr)
1803{
1804 if (!fsnotify_wq)
1805 return;
1806 /*
1807 * We cannot call queue_work(&tr->fsnotify_work) from here because it's
1808 * possible that we are called from __schedule() or do_idle(), which
1809 * could cause a deadlock.
1810 */
1811 irq_work_queue(&tr->fsnotify_irqwork);
1812}
1813
1814#else /* !LATENCY_FS_NOTIFY */
1815
1816#define trace_create_maxlat_file(tr, d_tracer) \
1817 trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \
1818 d_tracer, tr, &tracing_max_lat_fops)
1819
1820#endif
1821
1822/*
1823 * Copy the new maximum trace into the separate maximum-trace
1824 * structure. (this way the maximum trace is permanently saved,
1825 * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
1826 */
1827static void
1828__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1829{
1830 struct array_buffer *trace_buf = &tr->array_buffer;
1831 struct array_buffer *max_buf = &tr->max_buffer;
1832 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1833 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1834
1835 max_buf->cpu = cpu;
1836 max_buf->time_start = data->preempt_timestamp;
1837
1838 max_data->saved_latency = tr->max_latency;
1839 max_data->critical_start = data->critical_start;
1840 max_data->critical_end = data->critical_end;
1841
1842 strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1843 max_data->pid = tsk->pid;
1844 /*
1845 * If tsk == current, then use current_uid(), as that does not use
1846 * RCU. The irq tracer can be called out of RCU scope.
1847 */
1848 if (tsk == current)
1849 max_data->uid = current_uid();
1850 else
1851 max_data->uid = task_uid(tsk);
1852
1853 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1854 max_data->policy = tsk->policy;
1855 max_data->rt_priority = tsk->rt_priority;
1856
1857 /* record this tasks comm */
1858 tracing_record_cmdline(tsk);
1859 latency_fsnotify(tr);
1860}
1861
1862/**
1863 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1864 * @tr: tracer
1865 * @tsk: the task with the latency
1866 * @cpu: The cpu that initiated the trace.
1867 * @cond_data: User data associated with a conditional snapshot
1868 *
1869 * Flip the buffers between the @tr and the max_tr and record information
1870 * about which task was the cause of this latency.
1871 */
1872void
1873update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
1874 void *cond_data)
1875{
1876 if (tr->stop_count)
1877 return;
1878
1879 WARN_ON_ONCE(!irqs_disabled());
1880
1881 if (!tr->allocated_snapshot) {
1882 /* Only the nop tracer should hit this when disabling */
1883 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1884 return;
1885 }
1886
1887 arch_spin_lock(&tr->max_lock);
1888
1889 /* Inherit the recordable setting from array_buffer */
1890 if (ring_buffer_record_is_set_on(tr->array_buffer.buffer))
1891 ring_buffer_record_on(tr->max_buffer.buffer);
1892 else
1893 ring_buffer_record_off(tr->max_buffer.buffer);
1894
1895#ifdef CONFIG_TRACER_SNAPSHOT
1896 if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data)) {
1897 arch_spin_unlock(&tr->max_lock);
1898 return;
1899 }
1900#endif
1901 swap(tr->array_buffer.buffer, tr->max_buffer.buffer);
1902
1903 __update_max_tr(tr, tsk, cpu);
1904
1905 arch_spin_unlock(&tr->max_lock);
1906
1907 /* Any waiters on the old snapshot buffer need to wake up */
1908 ring_buffer_wake_waiters(tr->array_buffer.buffer, RING_BUFFER_ALL_CPUS);
1909}
1910
1911/**
1912 * update_max_tr_single - only copy one trace over, and reset the rest
1913 * @tr: tracer
1914 * @tsk: task with the latency
1915 * @cpu: the cpu of the buffer to copy.
1916 *
1917 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1918 */
1919void
1920update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1921{
1922 int ret;
1923
1924 if (tr->stop_count)
1925 return;
1926
1927 WARN_ON_ONCE(!irqs_disabled());
1928 if (!tr->allocated_snapshot) {
1929 /* Only the nop tracer should hit this when disabling */
1930 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1931 return;
1932 }
1933
1934 arch_spin_lock(&tr->max_lock);
1935
1936 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu);
1937
1938 if (ret == -EBUSY) {
1939 /*
1940 * We failed to swap the buffer due to a commit taking
1941 * place on this CPU. We fail to record, but we reset
1942 * the max trace buffer (no one writes directly to it)
1943 * and flag that it failed.
1944 * Another reason is resize is in progress.
1945 */
1946 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1947 "Failed to swap buffers due to commit or resize in progress\n");
1948 }
1949
1950 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1951
1952 __update_max_tr(tr, tsk, cpu);
1953 arch_spin_unlock(&tr->max_lock);
1954}
1955
1956#endif /* CONFIG_TRACER_MAX_TRACE */
1957
1958static int wait_on_pipe(struct trace_iterator *iter, int full)
1959{
1960 int ret;
1961
1962 /* Iterators are static, they should be filled or empty */
1963 if (trace_buffer_iter(iter, iter->cpu_file))
1964 return 0;
1965
1966 ret = ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file, full);
1967
1968#ifdef CONFIG_TRACER_MAX_TRACE
1969 /*
1970 * Make sure this is still the snapshot buffer, as if a snapshot were
1971 * to happen, this would now be the main buffer.
1972 */
1973 if (iter->snapshot)
1974 iter->array_buffer = &iter->tr->max_buffer;
1975#endif
1976 return ret;
1977}
1978
1979#ifdef CONFIG_FTRACE_STARTUP_TEST
1980static bool selftests_can_run;
1981
1982struct trace_selftests {
1983 struct list_head list;
1984 struct tracer *type;
1985};
1986
1987static LIST_HEAD(postponed_selftests);
1988
1989static int save_selftest(struct tracer *type)
1990{
1991 struct trace_selftests *selftest;
1992
1993 selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
1994 if (!selftest)
1995 return -ENOMEM;
1996
1997 selftest->type = type;
1998 list_add(&selftest->list, &postponed_selftests);
1999 return 0;
2000}
2001
2002static int run_tracer_selftest(struct tracer *type)
2003{
2004 struct trace_array *tr = &global_trace;
2005 struct tracer *saved_tracer = tr->current_trace;
2006 int ret;
2007
2008 if (!type->selftest || tracing_selftest_disabled)
2009 return 0;
2010
2011 /*
2012 * If a tracer registers early in boot up (before scheduling is
2013 * initialized and such), then do not run its selftests yet.
2014 * Instead, run it a little later in the boot process.
2015 */
2016 if (!selftests_can_run)
2017 return save_selftest(type);
2018
2019 if (!tracing_is_on()) {
2020 pr_warn("Selftest for tracer %s skipped due to tracing disabled\n",
2021 type->name);
2022 return 0;
2023 }
2024
2025 /*
2026 * Run a selftest on this tracer.
2027 * Here we reset the trace buffer, and set the current
2028 * tracer to be this tracer. The tracer can then run some
2029 * internal tracing to verify that everything is in order.
2030 * If we fail, we do not register this tracer.
2031 */
2032 tracing_reset_online_cpus(&tr->array_buffer);
2033
2034 tr->current_trace = type;
2035
2036#ifdef CONFIG_TRACER_MAX_TRACE
2037 if (type->use_max_tr) {
2038 /* If we expanded the buffers, make sure the max is expanded too */
2039 if (tr->ring_buffer_expanded)
2040 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
2041 RING_BUFFER_ALL_CPUS);
2042 tr->allocated_snapshot = true;
2043 }
2044#endif
2045
2046 /* the test is responsible for initializing and enabling */
2047 pr_info("Testing tracer %s: ", type->name);
2048 ret = type->selftest(type, tr);
2049 /* the test is responsible for resetting too */
2050 tr->current_trace = saved_tracer;
2051 if (ret) {
2052 printk(KERN_CONT "FAILED!\n");
2053 /* Add the warning after printing 'FAILED' */
2054 WARN_ON(1);
2055 return -1;
2056 }
2057 /* Only reset on passing, to avoid touching corrupted buffers */
2058 tracing_reset_online_cpus(&tr->array_buffer);
2059
2060#ifdef CONFIG_TRACER_MAX_TRACE
2061 if (type->use_max_tr) {
2062 tr->allocated_snapshot = false;
2063
2064 /* Shrink the max buffer again */
2065 if (tr->ring_buffer_expanded)
2066 ring_buffer_resize(tr->max_buffer.buffer, 1,
2067 RING_BUFFER_ALL_CPUS);
2068 }
2069#endif
2070
2071 printk(KERN_CONT "PASSED\n");
2072 return 0;
2073}
2074
2075static int do_run_tracer_selftest(struct tracer *type)
2076{
2077 int ret;
2078
2079 /*
2080 * Tests can take a long time, especially if they are run one after the
2081 * other, as does happen during bootup when all the tracers are
2082 * registered. This could cause the soft lockup watchdog to trigger.
2083 */
2084 cond_resched();
2085
2086 tracing_selftest_running = true;
2087 ret = run_tracer_selftest(type);
2088 tracing_selftest_running = false;
2089
2090 return ret;
2091}
2092
2093static __init int init_trace_selftests(void)
2094{
2095 struct trace_selftests *p, *n;
2096 struct tracer *t, **last;
2097 int ret;
2098
2099 selftests_can_run = true;
2100
2101 mutex_lock(&trace_types_lock);
2102
2103 if (list_empty(&postponed_selftests))
2104 goto out;
2105
2106 pr_info("Running postponed tracer tests:\n");
2107
2108 tracing_selftest_running = true;
2109 list_for_each_entry_safe(p, n, &postponed_selftests, list) {
2110 /* This loop can take minutes when sanitizers are enabled, so
2111 * lets make sure we allow RCU processing.
2112 */
2113 cond_resched();
2114 ret = run_tracer_selftest(p->type);
2115 /* If the test fails, then warn and remove from available_tracers */
2116 if (ret < 0) {
2117 WARN(1, "tracer: %s failed selftest, disabling\n",
2118 p->type->name);
2119 last = &trace_types;
2120 for (t = trace_types; t; t = t->next) {
2121 if (t == p->type) {
2122 *last = t->next;
2123 break;
2124 }
2125 last = &t->next;
2126 }
2127 }
2128 list_del(&p->list);
2129 kfree(p);
2130 }
2131 tracing_selftest_running = false;
2132
2133 out:
2134 mutex_unlock(&trace_types_lock);
2135
2136 return 0;
2137}
2138core_initcall(init_trace_selftests);
2139#else
2140static inline int run_tracer_selftest(struct tracer *type)
2141{
2142 return 0;
2143}
2144static inline int do_run_tracer_selftest(struct tracer *type)
2145{
2146 return 0;
2147}
2148#endif /* CONFIG_FTRACE_STARTUP_TEST */
2149
2150static void add_tracer_options(struct trace_array *tr, struct tracer *t);
2151
2152static void __init apply_trace_boot_options(void);
2153
2154/**
2155 * register_tracer - register a tracer with the ftrace system.
2156 * @type: the plugin for the tracer
2157 *
2158 * Register a new plugin tracer.
2159 */
2160int __init register_tracer(struct tracer *type)
2161{
2162 struct tracer *t;
2163 int ret = 0;
2164
2165 if (!type->name) {
2166 pr_info("Tracer must have a name\n");
2167 return -1;
2168 }
2169
2170 if (strlen(type->name) >= MAX_TRACER_SIZE) {
2171 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
2172 return -1;
2173 }
2174
2175 if (security_locked_down(LOCKDOWN_TRACEFS)) {
2176 pr_warn("Can not register tracer %s due to lockdown\n",
2177 type->name);
2178 return -EPERM;
2179 }
2180
2181 mutex_lock(&trace_types_lock);
2182
2183 for (t = trace_types; t; t = t->next) {
2184 if (strcmp(type->name, t->name) == 0) {
2185 /* already found */
2186 pr_info("Tracer %s already registered\n",
2187 type->name);
2188 ret = -1;
2189 goto out;
2190 }
2191 }
2192
2193 if (!type->set_flag)
2194 type->set_flag = &dummy_set_flag;
2195 if (!type->flags) {
2196 /*allocate a dummy tracer_flags*/
2197 type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
2198 if (!type->flags) {
2199 ret = -ENOMEM;
2200 goto out;
2201 }
2202 type->flags->val = 0;
2203 type->flags->opts = dummy_tracer_opt;
2204 } else
2205 if (!type->flags->opts)
2206 type->flags->opts = dummy_tracer_opt;
2207
2208 /* store the tracer for __set_tracer_option */
2209 type->flags->trace = type;
2210
2211 ret = do_run_tracer_selftest(type);
2212 if (ret < 0)
2213 goto out;
2214
2215 type->next = trace_types;
2216 trace_types = type;
2217 add_tracer_options(&global_trace, type);
2218
2219 out:
2220 mutex_unlock(&trace_types_lock);
2221
2222 if (ret || !default_bootup_tracer)
2223 goto out_unlock;
2224
2225 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
2226 goto out_unlock;
2227
2228 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
2229 /* Do we want this tracer to start on bootup? */
2230 tracing_set_tracer(&global_trace, type->name);
2231 default_bootup_tracer = NULL;
2232
2233 apply_trace_boot_options();
2234
2235 /* disable other selftests, since this will break it. */
2236 disable_tracing_selftest("running a tracer");
2237
2238 out_unlock:
2239 return ret;
2240}
2241
2242static void tracing_reset_cpu(struct array_buffer *buf, int cpu)
2243{
2244 struct trace_buffer *buffer = buf->buffer;
2245
2246 if (!buffer)
2247 return;
2248
2249 ring_buffer_record_disable(buffer);
2250
2251 /* Make sure all commits have finished */
2252 synchronize_rcu();
2253 ring_buffer_reset_cpu(buffer, cpu);
2254
2255 ring_buffer_record_enable(buffer);
2256}
2257
2258void tracing_reset_online_cpus(struct array_buffer *buf)
2259{
2260 struct trace_buffer *buffer = buf->buffer;
2261
2262 if (!buffer)
2263 return;
2264
2265 ring_buffer_record_disable(buffer);
2266
2267 /* Make sure all commits have finished */
2268 synchronize_rcu();
2269
2270 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
2271
2272 ring_buffer_reset_online_cpus(buffer);
2273
2274 ring_buffer_record_enable(buffer);
2275}
2276
2277/* Must have trace_types_lock held */
2278void tracing_reset_all_online_cpus_unlocked(void)
2279{
2280 struct trace_array *tr;
2281
2282 lockdep_assert_held(&trace_types_lock);
2283
2284 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2285 if (!tr->clear_trace)
2286 continue;
2287 tr->clear_trace = false;
2288 tracing_reset_online_cpus(&tr->array_buffer);
2289#ifdef CONFIG_TRACER_MAX_TRACE
2290 tracing_reset_online_cpus(&tr->max_buffer);
2291#endif
2292 }
2293}
2294
2295void tracing_reset_all_online_cpus(void)
2296{
2297 mutex_lock(&trace_types_lock);
2298 tracing_reset_all_online_cpus_unlocked();
2299 mutex_unlock(&trace_types_lock);
2300}
2301
2302/*
2303 * The tgid_map array maps from pid to tgid; i.e. the value stored at index i
2304 * is the tgid last observed corresponding to pid=i.
2305 */
2306static int *tgid_map;
2307
2308/* The maximum valid index into tgid_map. */
2309static size_t tgid_map_max;
2310
2311#define SAVED_CMDLINES_DEFAULT 128
2312#define NO_CMDLINE_MAP UINT_MAX
2313/*
2314 * Preemption must be disabled before acquiring trace_cmdline_lock.
2315 * The various trace_arrays' max_lock must be acquired in a context
2316 * where interrupt is disabled.
2317 */
2318static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
2319struct saved_cmdlines_buffer {
2320 unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
2321 unsigned *map_cmdline_to_pid;
2322 unsigned cmdline_num;
2323 int cmdline_idx;
2324 char saved_cmdlines[];
2325};
2326static struct saved_cmdlines_buffer *savedcmd;
2327
2328static inline char *get_saved_cmdlines(int idx)
2329{
2330 return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
2331}
2332
2333static inline void set_cmdline(int idx, const char *cmdline)
2334{
2335 strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
2336}
2337
2338static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
2339{
2340 int order = get_order(sizeof(*s) + s->cmdline_num * TASK_COMM_LEN);
2341
2342 kfree(s->map_cmdline_to_pid);
2343 kmemleak_free(s);
2344 free_pages((unsigned long)s, order);
2345}
2346
2347static struct saved_cmdlines_buffer *allocate_cmdlines_buffer(unsigned int val)
2348{
2349 struct saved_cmdlines_buffer *s;
2350 struct page *page;
2351 int orig_size, size;
2352 int order;
2353
2354 /* Figure out how much is needed to hold the given number of cmdlines */
2355 orig_size = sizeof(*s) + val * TASK_COMM_LEN;
2356 order = get_order(orig_size);
2357 size = 1 << (order + PAGE_SHIFT);
2358 page = alloc_pages(GFP_KERNEL, order);
2359 if (!page)
2360 return NULL;
2361
2362 s = page_address(page);
2363 kmemleak_alloc(s, size, 1, GFP_KERNEL);
2364 memset(s, 0, sizeof(*s));
2365
2366 /* Round up to actual allocation */
2367 val = (size - sizeof(*s)) / TASK_COMM_LEN;
2368 s->cmdline_num = val;
2369
2370 s->map_cmdline_to_pid = kmalloc_array(val,
2371 sizeof(*s->map_cmdline_to_pid),
2372 GFP_KERNEL);
2373 if (!s->map_cmdline_to_pid) {
2374 free_saved_cmdlines_buffer(s);
2375 return NULL;
2376 }
2377
2378 s->cmdline_idx = 0;
2379 memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
2380 sizeof(s->map_pid_to_cmdline));
2381 memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
2382 val * sizeof(*s->map_cmdline_to_pid));
2383
2384 return s;
2385}
2386
2387static int trace_create_savedcmd(void)
2388{
2389 savedcmd = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT);
2390
2391 return savedcmd ? 0 : -ENOMEM;
2392}
2393
2394int is_tracing_stopped(void)
2395{
2396 return global_trace.stop_count;
2397}
2398
2399static void tracing_start_tr(struct trace_array *tr)
2400{
2401 struct trace_buffer *buffer;
2402 unsigned long flags;
2403
2404 if (tracing_disabled)
2405 return;
2406
2407 raw_spin_lock_irqsave(&tr->start_lock, flags);
2408 if (--tr->stop_count) {
2409 if (WARN_ON_ONCE(tr->stop_count < 0)) {
2410 /* Someone screwed up their debugging */
2411 tr->stop_count = 0;
2412 }
2413 goto out;
2414 }
2415
2416 /* Prevent the buffers from switching */
2417 arch_spin_lock(&tr->max_lock);
2418
2419 buffer = tr->array_buffer.buffer;
2420 if (buffer)
2421 ring_buffer_record_enable(buffer);
2422
2423#ifdef CONFIG_TRACER_MAX_TRACE
2424 buffer = tr->max_buffer.buffer;
2425 if (buffer)
2426 ring_buffer_record_enable(buffer);
2427#endif
2428
2429 arch_spin_unlock(&tr->max_lock);
2430
2431 out:
2432 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2433}
2434
2435/**
2436 * tracing_start - quick start of the tracer
2437 *
2438 * If tracing is enabled but was stopped by tracing_stop,
2439 * this will start the tracer back up.
2440 */
2441void tracing_start(void)
2442
2443{
2444 return tracing_start_tr(&global_trace);
2445}
2446
2447static void tracing_stop_tr(struct trace_array *tr)
2448{
2449 struct trace_buffer *buffer;
2450 unsigned long flags;
2451
2452 raw_spin_lock_irqsave(&tr->start_lock, flags);
2453 if (tr->stop_count++)
2454 goto out;
2455
2456 /* Prevent the buffers from switching */
2457 arch_spin_lock(&tr->max_lock);
2458
2459 buffer = tr->array_buffer.buffer;
2460 if (buffer)
2461 ring_buffer_record_disable(buffer);
2462
2463#ifdef CONFIG_TRACER_MAX_TRACE
2464 buffer = tr->max_buffer.buffer;
2465 if (buffer)
2466 ring_buffer_record_disable(buffer);
2467#endif
2468
2469 arch_spin_unlock(&tr->max_lock);
2470
2471 out:
2472 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2473}
2474
2475/**
2476 * tracing_stop - quick stop of the tracer
2477 *
2478 * Light weight way to stop tracing. Use in conjunction with
2479 * tracing_start.
2480 */
2481void tracing_stop(void)
2482{
2483 return tracing_stop_tr(&global_trace);
2484}
2485
2486static int trace_save_cmdline(struct task_struct *tsk)
2487{
2488 unsigned tpid, idx;
2489
2490 /* treat recording of idle task as a success */
2491 if (!tsk->pid)
2492 return 1;
2493
2494 tpid = tsk->pid & (PID_MAX_DEFAULT - 1);
2495
2496 /*
2497 * It's not the end of the world if we don't get
2498 * the lock, but we also don't want to spin
2499 * nor do we want to disable interrupts,
2500 * so if we miss here, then better luck next time.
2501 *
2502 * This is called within the scheduler and wake up, so interrupts
2503 * had better been disabled and run queue lock been held.
2504 */
2505 lockdep_assert_preemption_disabled();
2506 if (!arch_spin_trylock(&trace_cmdline_lock))
2507 return 0;
2508
2509 idx = savedcmd->map_pid_to_cmdline[tpid];
2510 if (idx == NO_CMDLINE_MAP) {
2511 idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
2512
2513 savedcmd->map_pid_to_cmdline[tpid] = idx;
2514 savedcmd->cmdline_idx = idx;
2515 }
2516
2517 savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
2518 set_cmdline(idx, tsk->comm);
2519
2520 arch_spin_unlock(&trace_cmdline_lock);
2521
2522 return 1;
2523}
2524
2525static void __trace_find_cmdline(int pid, char comm[])
2526{
2527 unsigned map;
2528 int tpid;
2529
2530 if (!pid) {
2531 strcpy(comm, "<idle>");
2532 return;
2533 }
2534
2535 if (WARN_ON_ONCE(pid < 0)) {
2536 strcpy(comm, "<XXX>");
2537 return;
2538 }
2539
2540 tpid = pid & (PID_MAX_DEFAULT - 1);
2541 map = savedcmd->map_pid_to_cmdline[tpid];
2542 if (map != NO_CMDLINE_MAP) {
2543 tpid = savedcmd->map_cmdline_to_pid[map];
2544 if (tpid == pid) {
2545 strscpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
2546 return;
2547 }
2548 }
2549 strcpy(comm, "<...>");
2550}
2551
2552void trace_find_cmdline(int pid, char comm[])
2553{
2554 preempt_disable();
2555 arch_spin_lock(&trace_cmdline_lock);
2556
2557 __trace_find_cmdline(pid, comm);
2558
2559 arch_spin_unlock(&trace_cmdline_lock);
2560 preempt_enable();
2561}
2562
2563static int *trace_find_tgid_ptr(int pid)
2564{
2565 /*
2566 * Pairs with the smp_store_release in set_tracer_flag() to ensure that
2567 * if we observe a non-NULL tgid_map then we also observe the correct
2568 * tgid_map_max.
2569 */
2570 int *map = smp_load_acquire(&tgid_map);
2571
2572 if (unlikely(!map || pid > tgid_map_max))
2573 return NULL;
2574
2575 return &map[pid];
2576}
2577
2578int trace_find_tgid(int pid)
2579{
2580 int *ptr = trace_find_tgid_ptr(pid);
2581
2582 return ptr ? *ptr : 0;
2583}
2584
2585static int trace_save_tgid(struct task_struct *tsk)
2586{
2587 int *ptr;
2588
2589 /* treat recording of idle task as a success */
2590 if (!tsk->pid)
2591 return 1;
2592
2593 ptr = trace_find_tgid_ptr(tsk->pid);
2594 if (!ptr)
2595 return 0;
2596
2597 *ptr = tsk->tgid;
2598 return 1;
2599}
2600
2601static bool tracing_record_taskinfo_skip(int flags)
2602{
2603 if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID))))
2604 return true;
2605 if (!__this_cpu_read(trace_taskinfo_save))
2606 return true;
2607 return false;
2608}
2609
2610/**
2611 * tracing_record_taskinfo - record the task info of a task
2612 *
2613 * @task: task to record
2614 * @flags: TRACE_RECORD_CMDLINE for recording comm
2615 * TRACE_RECORD_TGID for recording tgid
2616 */
2617void tracing_record_taskinfo(struct task_struct *task, int flags)
2618{
2619 bool done;
2620
2621 if (tracing_record_taskinfo_skip(flags))
2622 return;
2623
2624 /*
2625 * Record as much task information as possible. If some fail, continue
2626 * to try to record the others.
2627 */
2628 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task);
2629 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task);
2630
2631 /* If recording any information failed, retry again soon. */
2632 if (!done)
2633 return;
2634
2635 __this_cpu_write(trace_taskinfo_save, false);
2636}
2637
2638/**
2639 * tracing_record_taskinfo_sched_switch - record task info for sched_switch
2640 *
2641 * @prev: previous task during sched_switch
2642 * @next: next task during sched_switch
2643 * @flags: TRACE_RECORD_CMDLINE for recording comm
2644 * TRACE_RECORD_TGID for recording tgid
2645 */
2646void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
2647 struct task_struct *next, int flags)
2648{
2649 bool done;
2650
2651 if (tracing_record_taskinfo_skip(flags))
2652 return;
2653
2654 /*
2655 * Record as much task information as possible. If some fail, continue
2656 * to try to record the others.
2657 */
2658 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev);
2659 done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next);
2660 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev);
2661 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next);
2662
2663 /* If recording any information failed, retry again soon. */
2664 if (!done)
2665 return;
2666
2667 __this_cpu_write(trace_taskinfo_save, false);
2668}
2669
2670/* Helpers to record a specific task information */
2671void tracing_record_cmdline(struct task_struct *task)
2672{
2673 tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE);
2674}
2675
2676void tracing_record_tgid(struct task_struct *task)
2677{
2678 tracing_record_taskinfo(task, TRACE_RECORD_TGID);
2679}
2680
2681/*
2682 * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
2683 * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
2684 * simplifies those functions and keeps them in sync.
2685 */
2686enum print_line_t trace_handle_return(struct trace_seq *s)
2687{
2688 return trace_seq_has_overflowed(s) ?
2689 TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
2690}
2691EXPORT_SYMBOL_GPL(trace_handle_return);
2692
2693static unsigned short migration_disable_value(void)
2694{
2695#if defined(CONFIG_SMP)
2696 return current->migration_disabled;
2697#else
2698 return 0;
2699#endif
2700}
2701
2702unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
2703{
2704 unsigned int trace_flags = irqs_status;
2705 unsigned int pc;
2706
2707 pc = preempt_count();
2708
2709 if (pc & NMI_MASK)
2710 trace_flags |= TRACE_FLAG_NMI;
2711 if (pc & HARDIRQ_MASK)
2712 trace_flags |= TRACE_FLAG_HARDIRQ;
2713 if (in_serving_softirq())
2714 trace_flags |= TRACE_FLAG_SOFTIRQ;
2715 if (softirq_count() >> (SOFTIRQ_SHIFT + 1))
2716 trace_flags |= TRACE_FLAG_BH_OFF;
2717
2718 if (tif_need_resched())
2719 trace_flags |= TRACE_FLAG_NEED_RESCHED;
2720 if (test_preempt_need_resched())
2721 trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
2722 return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) |
2723 (min_t(unsigned int, migration_disable_value(), 0xf)) << 4;
2724}
2725
2726struct ring_buffer_event *
2727trace_buffer_lock_reserve(struct trace_buffer *buffer,
2728 int type,
2729 unsigned long len,
2730 unsigned int trace_ctx)
2731{
2732 return __trace_buffer_lock_reserve(buffer, type, len, trace_ctx);
2733}
2734
2735DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
2736DEFINE_PER_CPU(int, trace_buffered_event_cnt);
2737static int trace_buffered_event_ref;
2738
2739/**
2740 * trace_buffered_event_enable - enable buffering events
2741 *
2742 * When events are being filtered, it is quicker to use a temporary
2743 * buffer to write the event data into if there's a likely chance
2744 * that it will not be committed. The discard of the ring buffer
2745 * is not as fast as committing, and is much slower than copying
2746 * a commit.
2747 *
2748 * When an event is to be filtered, allocate per cpu buffers to
2749 * write the event data into, and if the event is filtered and discarded
2750 * it is simply dropped, otherwise, the entire data is to be committed
2751 * in one shot.
2752 */
2753void trace_buffered_event_enable(void)
2754{
2755 struct ring_buffer_event *event;
2756 struct page *page;
2757 int cpu;
2758
2759 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2760
2761 if (trace_buffered_event_ref++)
2762 return;
2763
2764 for_each_tracing_cpu(cpu) {
2765 page = alloc_pages_node(cpu_to_node(cpu),
2766 GFP_KERNEL | __GFP_NORETRY, 0);
2767 /* This is just an optimization and can handle failures */
2768 if (!page) {
2769 pr_err("Failed to allocate event buffer\n");
2770 break;
2771 }
2772
2773 event = page_address(page);
2774 memset(event, 0, sizeof(*event));
2775
2776 per_cpu(trace_buffered_event, cpu) = event;
2777
2778 preempt_disable();
2779 if (cpu == smp_processor_id() &&
2780 __this_cpu_read(trace_buffered_event) !=
2781 per_cpu(trace_buffered_event, cpu))
2782 WARN_ON_ONCE(1);
2783 preempt_enable();
2784 }
2785}
2786
2787static void enable_trace_buffered_event(void *data)
2788{
2789 /* Probably not needed, but do it anyway */
2790 smp_rmb();
2791 this_cpu_dec(trace_buffered_event_cnt);
2792}
2793
2794static void disable_trace_buffered_event(void *data)
2795{
2796 this_cpu_inc(trace_buffered_event_cnt);
2797}
2798
2799/**
2800 * trace_buffered_event_disable - disable buffering events
2801 *
2802 * When a filter is removed, it is faster to not use the buffered
2803 * events, and to commit directly into the ring buffer. Free up
2804 * the temp buffers when there are no more users. This requires
2805 * special synchronization with current events.
2806 */
2807void trace_buffered_event_disable(void)
2808{
2809 int cpu;
2810
2811 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2812
2813 if (WARN_ON_ONCE(!trace_buffered_event_ref))
2814 return;
2815
2816 if (--trace_buffered_event_ref)
2817 return;
2818
2819 /* For each CPU, set the buffer as used. */
2820 on_each_cpu_mask(tracing_buffer_mask, disable_trace_buffered_event,
2821 NULL, true);
2822
2823 /* Wait for all current users to finish */
2824 synchronize_rcu();
2825
2826 for_each_tracing_cpu(cpu) {
2827 free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
2828 per_cpu(trace_buffered_event, cpu) = NULL;
2829 }
2830
2831 /*
2832 * Wait for all CPUs that potentially started checking if they can use
2833 * their event buffer only after the previous synchronize_rcu() call and
2834 * they still read a valid pointer from trace_buffered_event. It must be
2835 * ensured they don't see cleared trace_buffered_event_cnt else they
2836 * could wrongly decide to use the pointed-to buffer which is now freed.
2837 */
2838 synchronize_rcu();
2839
2840 /* For each CPU, relinquish the buffer */
2841 on_each_cpu_mask(tracing_buffer_mask, enable_trace_buffered_event, NULL,
2842 true);
2843}
2844
2845static struct trace_buffer *temp_buffer;
2846
2847struct ring_buffer_event *
2848trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
2849 struct trace_event_file *trace_file,
2850 int type, unsigned long len,
2851 unsigned int trace_ctx)
2852{
2853 struct ring_buffer_event *entry;
2854 struct trace_array *tr = trace_file->tr;
2855 int val;
2856
2857 *current_rb = tr->array_buffer.buffer;
2858
2859 if (!tr->no_filter_buffering_ref &&
2860 (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED))) {
2861 preempt_disable_notrace();
2862 /*
2863 * Filtering is on, so try to use the per cpu buffer first.
2864 * This buffer will simulate a ring_buffer_event,
2865 * where the type_len is zero and the array[0] will
2866 * hold the full length.
2867 * (see include/linux/ring-buffer.h for details on
2868 * how the ring_buffer_event is structured).
2869 *
2870 * Using a temp buffer during filtering and copying it
2871 * on a matched filter is quicker than writing directly
2872 * into the ring buffer and then discarding it when
2873 * it doesn't match. That is because the discard
2874 * requires several atomic operations to get right.
2875 * Copying on match and doing nothing on a failed match
2876 * is still quicker than no copy on match, but having
2877 * to discard out of the ring buffer on a failed match.
2878 */
2879 if ((entry = __this_cpu_read(trace_buffered_event))) {
2880 int max_len = PAGE_SIZE - struct_size(entry, array, 1);
2881
2882 val = this_cpu_inc_return(trace_buffered_event_cnt);
2883
2884 /*
2885 * Preemption is disabled, but interrupts and NMIs
2886 * can still come in now. If that happens after
2887 * the above increment, then it will have to go
2888 * back to the old method of allocating the event
2889 * on the ring buffer, and if the filter fails, it
2890 * will have to call ring_buffer_discard_commit()
2891 * to remove it.
2892 *
2893 * Need to also check the unlikely case that the
2894 * length is bigger than the temp buffer size.
2895 * If that happens, then the reserve is pretty much
2896 * guaranteed to fail, as the ring buffer currently
2897 * only allows events less than a page. But that may
2898 * change in the future, so let the ring buffer reserve
2899 * handle the failure in that case.
2900 */
2901 if (val == 1 && likely(len <= max_len)) {
2902 trace_event_setup(entry, type, trace_ctx);
2903 entry->array[0] = len;
2904 /* Return with preemption disabled */
2905 return entry;
2906 }
2907 this_cpu_dec(trace_buffered_event_cnt);
2908 }
2909 /* __trace_buffer_lock_reserve() disables preemption */
2910 preempt_enable_notrace();
2911 }
2912
2913 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2914 trace_ctx);
2915 /*
2916 * If tracing is off, but we have triggers enabled
2917 * we still need to look at the event data. Use the temp_buffer
2918 * to store the trace event for the trigger to use. It's recursive
2919 * safe and will not be recorded anywhere.
2920 */
2921 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
2922 *current_rb = temp_buffer;
2923 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2924 trace_ctx);
2925 }
2926 return entry;
2927}
2928EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
2929
2930static DEFINE_RAW_SPINLOCK(tracepoint_iter_lock);
2931static DEFINE_MUTEX(tracepoint_printk_mutex);
2932
2933static void output_printk(struct trace_event_buffer *fbuffer)
2934{
2935 struct trace_event_call *event_call;
2936 struct trace_event_file *file;
2937 struct trace_event *event;
2938 unsigned long flags;
2939 struct trace_iterator *iter = tracepoint_print_iter;
2940
2941 /* We should never get here if iter is NULL */
2942 if (WARN_ON_ONCE(!iter))
2943 return;
2944
2945 event_call = fbuffer->trace_file->event_call;
2946 if (!event_call || !event_call->event.funcs ||
2947 !event_call->event.funcs->trace)
2948 return;
2949
2950 file = fbuffer->trace_file;
2951 if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) ||
2952 (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
2953 !filter_match_preds(file->filter, fbuffer->entry)))
2954 return;
2955
2956 event = &fbuffer->trace_file->event_call->event;
2957
2958 raw_spin_lock_irqsave(&tracepoint_iter_lock, flags);
2959 trace_seq_init(&iter->seq);
2960 iter->ent = fbuffer->entry;
2961 event_call->event.funcs->trace(iter, 0, event);
2962 trace_seq_putc(&iter->seq, 0);
2963 printk("%s", iter->seq.buffer);
2964
2965 raw_spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
2966}
2967
2968int tracepoint_printk_sysctl(struct ctl_table *table, int write,
2969 void *buffer, size_t *lenp,
2970 loff_t *ppos)
2971{
2972 int save_tracepoint_printk;
2973 int ret;
2974
2975 mutex_lock(&tracepoint_printk_mutex);
2976 save_tracepoint_printk = tracepoint_printk;
2977
2978 ret = proc_dointvec(table, write, buffer, lenp, ppos);
2979
2980 /*
2981 * This will force exiting early, as tracepoint_printk
2982 * is always zero when tracepoint_printk_iter is not allocated
2983 */
2984 if (!tracepoint_print_iter)
2985 tracepoint_printk = 0;
2986
2987 if (save_tracepoint_printk == tracepoint_printk)
2988 goto out;
2989
2990 if (tracepoint_printk)
2991 static_key_enable(&tracepoint_printk_key.key);
2992 else
2993 static_key_disable(&tracepoint_printk_key.key);
2994
2995 out:
2996 mutex_unlock(&tracepoint_printk_mutex);
2997
2998 return ret;
2999}
3000
3001void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
3002{
3003 enum event_trigger_type tt = ETT_NONE;
3004 struct trace_event_file *file = fbuffer->trace_file;
3005
3006 if (__event_trigger_test_discard(file, fbuffer->buffer, fbuffer->event,
3007 fbuffer->entry, &tt))
3008 goto discard;
3009
3010 if (static_key_false(&tracepoint_printk_key.key))
3011 output_printk(fbuffer);
3012
3013 if (static_branch_unlikely(&trace_event_exports_enabled))
3014 ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT);
3015
3016 trace_buffer_unlock_commit_regs(file->tr, fbuffer->buffer,
3017 fbuffer->event, fbuffer->trace_ctx, fbuffer->regs);
3018
3019discard:
3020 if (tt)
3021 event_triggers_post_call(file, tt);
3022
3023}
3024EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
3025
3026/*
3027 * Skip 3:
3028 *
3029 * trace_buffer_unlock_commit_regs()
3030 * trace_event_buffer_commit()
3031 * trace_event_raw_event_xxx()
3032 */
3033# define STACK_SKIP 3
3034
3035void trace_buffer_unlock_commit_regs(struct trace_array *tr,
3036 struct trace_buffer *buffer,
3037 struct ring_buffer_event *event,
3038 unsigned int trace_ctx,
3039 struct pt_regs *regs)
3040{
3041 __buffer_unlock_commit(buffer, event);
3042
3043 /*
3044 * If regs is not set, then skip the necessary functions.
3045 * Note, we can still get here via blktrace, wakeup tracer
3046 * and mmiotrace, but that's ok if they lose a function or
3047 * two. They are not that meaningful.
3048 */
3049 ftrace_trace_stack(tr, buffer, trace_ctx, regs ? 0 : STACK_SKIP, regs);
3050 ftrace_trace_userstack(tr, buffer, trace_ctx);
3051}
3052
3053/*
3054 * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
3055 */
3056void
3057trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
3058 struct ring_buffer_event *event)
3059{
3060 __buffer_unlock_commit(buffer, event);
3061}
3062
3063void
3064trace_function(struct trace_array *tr, unsigned long ip, unsigned long
3065 parent_ip, unsigned int trace_ctx)
3066{
3067 struct trace_event_call *call = &event_function;
3068 struct trace_buffer *buffer = tr->array_buffer.buffer;
3069 struct ring_buffer_event *event;
3070 struct ftrace_entry *entry;
3071
3072 event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
3073 trace_ctx);
3074 if (!event)
3075 return;
3076 entry = ring_buffer_event_data(event);
3077 entry->ip = ip;
3078 entry->parent_ip = parent_ip;
3079
3080 if (!call_filter_check_discard(call, entry, buffer, event)) {
3081 if (static_branch_unlikely(&trace_function_exports_enabled))
3082 ftrace_exports(event, TRACE_EXPORT_FUNCTION);
3083 __buffer_unlock_commit(buffer, event);
3084 }
3085}
3086
3087#ifdef CONFIG_STACKTRACE
3088
3089/* Allow 4 levels of nesting: normal, softirq, irq, NMI */
3090#define FTRACE_KSTACK_NESTING 4
3091
3092#define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING)
3093
3094struct ftrace_stack {
3095 unsigned long calls[FTRACE_KSTACK_ENTRIES];
3096};
3097
3098
3099struct ftrace_stacks {
3100 struct ftrace_stack stacks[FTRACE_KSTACK_NESTING];
3101};
3102
3103static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
3104static DEFINE_PER_CPU(int, ftrace_stack_reserve);
3105
3106static void __ftrace_trace_stack(struct trace_buffer *buffer,
3107 unsigned int trace_ctx,
3108 int skip, struct pt_regs *regs)
3109{
3110 struct trace_event_call *call = &event_kernel_stack;
3111 struct ring_buffer_event *event;
3112 unsigned int size, nr_entries;
3113 struct ftrace_stack *fstack;
3114 struct stack_entry *entry;
3115 int stackidx;
3116
3117 /*
3118 * Add one, for this function and the call to save_stack_trace()
3119 * If regs is set, then these functions will not be in the way.
3120 */
3121#ifndef CONFIG_UNWINDER_ORC
3122 if (!regs)
3123 skip++;
3124#endif
3125
3126 preempt_disable_notrace();
3127
3128 stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
3129
3130 /* This should never happen. If it does, yell once and skip */
3131 if (WARN_ON_ONCE(stackidx >= FTRACE_KSTACK_NESTING))
3132 goto out;
3133
3134 /*
3135 * The above __this_cpu_inc_return() is 'atomic' cpu local. An
3136 * interrupt will either see the value pre increment or post
3137 * increment. If the interrupt happens pre increment it will have
3138 * restored the counter when it returns. We just need a barrier to
3139 * keep gcc from moving things around.
3140 */
3141 barrier();
3142
3143 fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx;
3144 size = ARRAY_SIZE(fstack->calls);
3145
3146 if (regs) {
3147 nr_entries = stack_trace_save_regs(regs, fstack->calls,
3148 size, skip);
3149 } else {
3150 nr_entries = stack_trace_save(fstack->calls, size, skip);
3151 }
3152
3153 event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
3154 struct_size(entry, caller, nr_entries),
3155 trace_ctx);
3156 if (!event)
3157 goto out;
3158 entry = ring_buffer_event_data(event);
3159
3160 entry->size = nr_entries;
3161 memcpy(&entry->caller, fstack->calls,
3162 flex_array_size(entry, caller, nr_entries));
3163
3164 if (!call_filter_check_discard(call, entry, buffer, event))
3165 __buffer_unlock_commit(buffer, event);
3166
3167 out:
3168 /* Again, don't let gcc optimize things here */
3169 barrier();
3170 __this_cpu_dec(ftrace_stack_reserve);
3171 preempt_enable_notrace();
3172
3173}
3174
3175static inline void ftrace_trace_stack(struct trace_array *tr,
3176 struct trace_buffer *buffer,
3177 unsigned int trace_ctx,
3178 int skip, struct pt_regs *regs)
3179{
3180 if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
3181 return;
3182
3183 __ftrace_trace_stack(buffer, trace_ctx, skip, regs);
3184}
3185
3186void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
3187 int skip)
3188{
3189 struct trace_buffer *buffer = tr->array_buffer.buffer;
3190
3191 if (rcu_is_watching()) {
3192 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
3193 return;
3194 }
3195
3196 if (WARN_ON_ONCE(IS_ENABLED(CONFIG_GENERIC_ENTRY)))
3197 return;
3198
3199 /*
3200 * When an NMI triggers, RCU is enabled via ct_nmi_enter(),
3201 * but if the above rcu_is_watching() failed, then the NMI
3202 * triggered someplace critical, and ct_irq_enter() should
3203 * not be called from NMI.
3204 */
3205 if (unlikely(in_nmi()))
3206 return;
3207
3208 ct_irq_enter_irqson();
3209 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
3210 ct_irq_exit_irqson();
3211}
3212
3213/**
3214 * trace_dump_stack - record a stack back trace in the trace buffer
3215 * @skip: Number of functions to skip (helper handlers)
3216 */
3217void trace_dump_stack(int skip)
3218{
3219 if (tracing_disabled || tracing_selftest_running)
3220 return;
3221
3222#ifndef CONFIG_UNWINDER_ORC
3223 /* Skip 1 to skip this function. */
3224 skip++;
3225#endif
3226 __ftrace_trace_stack(global_trace.array_buffer.buffer,
3227 tracing_gen_ctx(), skip, NULL);
3228}
3229EXPORT_SYMBOL_GPL(trace_dump_stack);
3230
3231#ifdef CONFIG_USER_STACKTRACE_SUPPORT
3232static DEFINE_PER_CPU(int, user_stack_count);
3233
3234static void
3235ftrace_trace_userstack(struct trace_array *tr,
3236 struct trace_buffer *buffer, unsigned int trace_ctx)
3237{
3238 struct trace_event_call *call = &event_user_stack;
3239 struct ring_buffer_event *event;
3240 struct userstack_entry *entry;
3241
3242 if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE))
3243 return;
3244
3245 /*
3246 * NMIs can not handle page faults, even with fix ups.
3247 * The save user stack can (and often does) fault.
3248 */
3249 if (unlikely(in_nmi()))
3250 return;
3251
3252 /*
3253 * prevent recursion, since the user stack tracing may
3254 * trigger other kernel events.
3255 */
3256 preempt_disable();
3257 if (__this_cpu_read(user_stack_count))
3258 goto out;
3259
3260 __this_cpu_inc(user_stack_count);
3261
3262 event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
3263 sizeof(*entry), trace_ctx);
3264 if (!event)
3265 goto out_drop_count;
3266 entry = ring_buffer_event_data(event);
3267
3268 entry->tgid = current->tgid;
3269 memset(&entry->caller, 0, sizeof(entry->caller));
3270
3271 stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES);
3272 if (!call_filter_check_discard(call, entry, buffer, event))
3273 __buffer_unlock_commit(buffer, event);
3274
3275 out_drop_count:
3276 __this_cpu_dec(user_stack_count);
3277 out:
3278 preempt_enable();
3279}
3280#else /* CONFIG_USER_STACKTRACE_SUPPORT */
3281static void ftrace_trace_userstack(struct trace_array *tr,
3282 struct trace_buffer *buffer,
3283 unsigned int trace_ctx)
3284{
3285}
3286#endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
3287
3288#endif /* CONFIG_STACKTRACE */
3289
3290static inline void
3291func_repeats_set_delta_ts(struct func_repeats_entry *entry,
3292 unsigned long long delta)
3293{
3294 entry->bottom_delta_ts = delta & U32_MAX;
3295 entry->top_delta_ts = (delta >> 32);
3296}
3297
3298void trace_last_func_repeats(struct trace_array *tr,
3299 struct trace_func_repeats *last_info,
3300 unsigned int trace_ctx)
3301{
3302 struct trace_buffer *buffer = tr->array_buffer.buffer;
3303 struct func_repeats_entry *entry;
3304 struct ring_buffer_event *event;
3305 u64 delta;
3306
3307 event = __trace_buffer_lock_reserve(buffer, TRACE_FUNC_REPEATS,
3308 sizeof(*entry), trace_ctx);
3309 if (!event)
3310 return;
3311
3312 delta = ring_buffer_event_time_stamp(buffer, event) -
3313 last_info->ts_last_call;
3314
3315 entry = ring_buffer_event_data(event);
3316 entry->ip = last_info->ip;
3317 entry->parent_ip = last_info->parent_ip;
3318 entry->count = last_info->count;
3319 func_repeats_set_delta_ts(entry, delta);
3320
3321 __buffer_unlock_commit(buffer, event);
3322}
3323
3324/* created for use with alloc_percpu */
3325struct trace_buffer_struct {
3326 int nesting;
3327 char buffer[4][TRACE_BUF_SIZE];
3328};
3329
3330static struct trace_buffer_struct __percpu *trace_percpu_buffer;
3331
3332/*
3333 * This allows for lockless recording. If we're nested too deeply, then
3334 * this returns NULL.
3335 */
3336static char *get_trace_buf(void)
3337{
3338 struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
3339
3340 if (!trace_percpu_buffer || buffer->nesting >= 4)
3341 return NULL;
3342
3343 buffer->nesting++;
3344
3345 /* Interrupts must see nesting incremented before we use the buffer */
3346 barrier();
3347 return &buffer->buffer[buffer->nesting - 1][0];
3348}
3349
3350static void put_trace_buf(void)
3351{
3352 /* Don't let the decrement of nesting leak before this */
3353 barrier();
3354 this_cpu_dec(trace_percpu_buffer->nesting);
3355}
3356
3357static int alloc_percpu_trace_buffer(void)
3358{
3359 struct trace_buffer_struct __percpu *buffers;
3360
3361 if (trace_percpu_buffer)
3362 return 0;
3363
3364 buffers = alloc_percpu(struct trace_buffer_struct);
3365 if (MEM_FAIL(!buffers, "Could not allocate percpu trace_printk buffer"))
3366 return -ENOMEM;
3367
3368 trace_percpu_buffer = buffers;
3369 return 0;
3370}
3371
3372static int buffers_allocated;
3373
3374void trace_printk_init_buffers(void)
3375{
3376 if (buffers_allocated)
3377 return;
3378
3379 if (alloc_percpu_trace_buffer())
3380 return;
3381
3382 /* trace_printk() is for debug use only. Don't use it in production. */
3383
3384 pr_warn("\n");
3385 pr_warn("**********************************************************\n");
3386 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3387 pr_warn("** **\n");
3388 pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
3389 pr_warn("** **\n");
3390 pr_warn("** This means that this is a DEBUG kernel and it is **\n");
3391 pr_warn("** unsafe for production use. **\n");
3392 pr_warn("** **\n");
3393 pr_warn("** If you see this message and you are not debugging **\n");
3394 pr_warn("** the kernel, report this immediately to your vendor! **\n");
3395 pr_warn("** **\n");
3396 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3397 pr_warn("**********************************************************\n");
3398
3399 /* Expand the buffers to set size */
3400 tracing_update_buffers(&global_trace);
3401
3402 buffers_allocated = 1;
3403
3404 /*
3405 * trace_printk_init_buffers() can be called by modules.
3406 * If that happens, then we need to start cmdline recording
3407 * directly here. If the global_trace.buffer is already
3408 * allocated here, then this was called by module code.
3409 */
3410 if (global_trace.array_buffer.buffer)
3411 tracing_start_cmdline_record();
3412}
3413EXPORT_SYMBOL_GPL(trace_printk_init_buffers);
3414
3415void trace_printk_start_comm(void)
3416{
3417 /* Start tracing comms if trace printk is set */
3418 if (!buffers_allocated)
3419 return;
3420 tracing_start_cmdline_record();
3421}
3422
3423static void trace_printk_start_stop_comm(int enabled)
3424{
3425 if (!buffers_allocated)
3426 return;
3427
3428 if (enabled)
3429 tracing_start_cmdline_record();
3430 else
3431 tracing_stop_cmdline_record();
3432}
3433
3434/**
3435 * trace_vbprintk - write binary msg to tracing buffer
3436 * @ip: The address of the caller
3437 * @fmt: The string format to write to the buffer
3438 * @args: Arguments for @fmt
3439 */
3440int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
3441{
3442 struct trace_event_call *call = &event_bprint;
3443 struct ring_buffer_event *event;
3444 struct trace_buffer *buffer;
3445 struct trace_array *tr = &global_trace;
3446 struct bprint_entry *entry;
3447 unsigned int trace_ctx;
3448 char *tbuffer;
3449 int len = 0, size;
3450
3451 if (unlikely(tracing_selftest_running || tracing_disabled))
3452 return 0;
3453
3454 /* Don't pollute graph traces with trace_vprintk internals */
3455 pause_graph_tracing();
3456
3457 trace_ctx = tracing_gen_ctx();
3458 preempt_disable_notrace();
3459
3460 tbuffer = get_trace_buf();
3461 if (!tbuffer) {
3462 len = 0;
3463 goto out_nobuffer;
3464 }
3465
3466 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
3467
3468 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
3469 goto out_put;
3470
3471 size = sizeof(*entry) + sizeof(u32) * len;
3472 buffer = tr->array_buffer.buffer;
3473 ring_buffer_nest_start(buffer);
3474 event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
3475 trace_ctx);
3476 if (!event)
3477 goto out;
3478 entry = ring_buffer_event_data(event);
3479 entry->ip = ip;
3480 entry->fmt = fmt;
3481
3482 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
3483 if (!call_filter_check_discard(call, entry, buffer, event)) {
3484 __buffer_unlock_commit(buffer, event);
3485 ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL);
3486 }
3487
3488out:
3489 ring_buffer_nest_end(buffer);
3490out_put:
3491 put_trace_buf();
3492
3493out_nobuffer:
3494 preempt_enable_notrace();
3495 unpause_graph_tracing();
3496
3497 return len;
3498}
3499EXPORT_SYMBOL_GPL(trace_vbprintk);
3500
3501__printf(3, 0)
3502static int
3503__trace_array_vprintk(struct trace_buffer *buffer,
3504 unsigned long ip, const char *fmt, va_list args)
3505{
3506 struct trace_event_call *call = &event_print;
3507 struct ring_buffer_event *event;
3508 int len = 0, size;
3509 struct print_entry *entry;
3510 unsigned int trace_ctx;
3511 char *tbuffer;
3512
3513 if (tracing_disabled)
3514 return 0;
3515
3516 /* Don't pollute graph traces with trace_vprintk internals */
3517 pause_graph_tracing();
3518
3519 trace_ctx = tracing_gen_ctx();
3520 preempt_disable_notrace();
3521
3522
3523 tbuffer = get_trace_buf();
3524 if (!tbuffer) {
3525 len = 0;
3526 goto out_nobuffer;
3527 }
3528
3529 len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
3530
3531 size = sizeof(*entry) + len + 1;
3532 ring_buffer_nest_start(buffer);
3533 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3534 trace_ctx);
3535 if (!event)
3536 goto out;
3537 entry = ring_buffer_event_data(event);
3538 entry->ip = ip;
3539
3540 memcpy(&entry->buf, tbuffer, len + 1);
3541 if (!call_filter_check_discard(call, entry, buffer, event)) {
3542 __buffer_unlock_commit(buffer, event);
3543 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 6, NULL);
3544 }
3545
3546out:
3547 ring_buffer_nest_end(buffer);
3548 put_trace_buf();
3549
3550out_nobuffer:
3551 preempt_enable_notrace();
3552 unpause_graph_tracing();
3553
3554 return len;
3555}
3556
3557__printf(3, 0)
3558int trace_array_vprintk(struct trace_array *tr,
3559 unsigned long ip, const char *fmt, va_list args)
3560{
3561 if (tracing_selftest_running && tr == &global_trace)
3562 return 0;
3563
3564 return __trace_array_vprintk(tr->array_buffer.buffer, ip, fmt, args);
3565}
3566
3567/**
3568 * trace_array_printk - Print a message to a specific instance
3569 * @tr: The instance trace_array descriptor
3570 * @ip: The instruction pointer that this is called from.
3571 * @fmt: The format to print (printf format)
3572 *
3573 * If a subsystem sets up its own instance, they have the right to
3574 * printk strings into their tracing instance buffer using this
3575 * function. Note, this function will not write into the top level
3576 * buffer (use trace_printk() for that), as writing into the top level
3577 * buffer should only have events that can be individually disabled.
3578 * trace_printk() is only used for debugging a kernel, and should not
3579 * be ever incorporated in normal use.
3580 *
3581 * trace_array_printk() can be used, as it will not add noise to the
3582 * top level tracing buffer.
3583 *
3584 * Note, trace_array_init_printk() must be called on @tr before this
3585 * can be used.
3586 */
3587__printf(3, 0)
3588int trace_array_printk(struct trace_array *tr,
3589 unsigned long ip, const char *fmt, ...)
3590{
3591 int ret;
3592 va_list ap;
3593
3594 if (!tr)
3595 return -ENOENT;
3596
3597 /* This is only allowed for created instances */
3598 if (tr == &global_trace)
3599 return 0;
3600
3601 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
3602 return 0;
3603
3604 va_start(ap, fmt);
3605 ret = trace_array_vprintk(tr, ip, fmt, ap);
3606 va_end(ap);
3607 return ret;
3608}
3609EXPORT_SYMBOL_GPL(trace_array_printk);
3610
3611/**
3612 * trace_array_init_printk - Initialize buffers for trace_array_printk()
3613 * @tr: The trace array to initialize the buffers for
3614 *
3615 * As trace_array_printk() only writes into instances, they are OK to
3616 * have in the kernel (unlike trace_printk()). This needs to be called
3617 * before trace_array_printk() can be used on a trace_array.
3618 */
3619int trace_array_init_printk(struct trace_array *tr)
3620{
3621 if (!tr)
3622 return -ENOENT;
3623
3624 /* This is only allowed for created instances */
3625 if (tr == &global_trace)
3626 return -EINVAL;
3627
3628 return alloc_percpu_trace_buffer();
3629}
3630EXPORT_SYMBOL_GPL(trace_array_init_printk);
3631
3632__printf(3, 4)
3633int trace_array_printk_buf(struct trace_buffer *buffer,
3634 unsigned long ip, const char *fmt, ...)
3635{
3636 int ret;
3637 va_list ap;
3638
3639 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
3640 return 0;
3641
3642 va_start(ap, fmt);
3643 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
3644 va_end(ap);
3645 return ret;
3646}
3647
3648__printf(2, 0)
3649int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3650{
3651 return trace_array_vprintk(&global_trace, ip, fmt, args);
3652}
3653EXPORT_SYMBOL_GPL(trace_vprintk);
3654
3655static void trace_iterator_increment(struct trace_iterator *iter)
3656{
3657 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
3658
3659 iter->idx++;
3660 if (buf_iter)
3661 ring_buffer_iter_advance(buf_iter);
3662}
3663
3664static struct trace_entry *
3665peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
3666 unsigned long *lost_events)
3667{
3668 struct ring_buffer_event *event;
3669 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
3670
3671 if (buf_iter) {
3672 event = ring_buffer_iter_peek(buf_iter, ts);
3673 if (lost_events)
3674 *lost_events = ring_buffer_iter_dropped(buf_iter) ?
3675 (unsigned long)-1 : 0;
3676 } else {
3677 event = ring_buffer_peek(iter->array_buffer->buffer, cpu, ts,
3678 lost_events);
3679 }
3680
3681 if (event) {
3682 iter->ent_size = ring_buffer_event_length(event);
3683 return ring_buffer_event_data(event);
3684 }
3685 iter->ent_size = 0;
3686 return NULL;
3687}
3688
3689static struct trace_entry *
3690__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
3691 unsigned long *missing_events, u64 *ent_ts)
3692{
3693 struct trace_buffer *buffer = iter->array_buffer->buffer;
3694 struct trace_entry *ent, *next = NULL;
3695 unsigned long lost_events = 0, next_lost = 0;
3696 int cpu_file = iter->cpu_file;
3697 u64 next_ts = 0, ts;
3698 int next_cpu = -1;
3699 int next_size = 0;
3700 int cpu;
3701
3702 /*
3703 * If we are in a per_cpu trace file, don't bother by iterating over
3704 * all cpu and peek directly.
3705 */
3706 if (cpu_file > RING_BUFFER_ALL_CPUS) {
3707 if (ring_buffer_empty_cpu(buffer, cpu_file))
3708 return NULL;
3709 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
3710 if (ent_cpu)
3711 *ent_cpu = cpu_file;
3712
3713 return ent;
3714 }
3715
3716 for_each_tracing_cpu(cpu) {
3717
3718 if (ring_buffer_empty_cpu(buffer, cpu))
3719 continue;
3720
3721 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
3722
3723 /*
3724 * Pick the entry with the smallest timestamp:
3725 */
3726 if (ent && (!next || ts < next_ts)) {
3727 next = ent;
3728 next_cpu = cpu;
3729 next_ts = ts;
3730 next_lost = lost_events;
3731 next_size = iter->ent_size;
3732 }
3733 }
3734
3735 iter->ent_size = next_size;
3736
3737 if (ent_cpu)
3738 *ent_cpu = next_cpu;
3739
3740 if (ent_ts)
3741 *ent_ts = next_ts;
3742
3743 if (missing_events)
3744 *missing_events = next_lost;
3745
3746 return next;
3747}
3748
3749#define STATIC_FMT_BUF_SIZE 128
3750static char static_fmt_buf[STATIC_FMT_BUF_SIZE];
3751
3752char *trace_iter_expand_format(struct trace_iterator *iter)
3753{
3754 char *tmp;
3755
3756 /*
3757 * iter->tr is NULL when used with tp_printk, which makes
3758 * this get called where it is not safe to call krealloc().
3759 */
3760 if (!iter->tr || iter->fmt == static_fmt_buf)
3761 return NULL;
3762
3763 tmp = krealloc(iter->fmt, iter->fmt_size + STATIC_FMT_BUF_SIZE,
3764 GFP_KERNEL);
3765 if (tmp) {
3766 iter->fmt_size += STATIC_FMT_BUF_SIZE;
3767 iter->fmt = tmp;
3768 }
3769
3770 return tmp;
3771}
3772
3773/* Returns true if the string is safe to dereference from an event */
3774static bool trace_safe_str(struct trace_iterator *iter, const char *str,
3775 bool star, int len)
3776{
3777 unsigned long addr = (unsigned long)str;
3778 struct trace_event *trace_event;
3779 struct trace_event_call *event;
3780
3781 /* Ignore strings with no length */
3782 if (star && !len)
3783 return true;
3784
3785 /* OK if part of the event data */
3786 if ((addr >= (unsigned long)iter->ent) &&
3787 (addr < (unsigned long)iter->ent + iter->ent_size))
3788 return true;
3789
3790 /* OK if part of the temp seq buffer */
3791 if ((addr >= (unsigned long)iter->tmp_seq.buffer) &&
3792 (addr < (unsigned long)iter->tmp_seq.buffer + TRACE_SEQ_BUFFER_SIZE))
3793 return true;
3794
3795 /* Core rodata can not be freed */
3796 if (is_kernel_rodata(addr))
3797 return true;
3798
3799 if (trace_is_tracepoint_string(str))
3800 return true;
3801
3802 /*
3803 * Now this could be a module event, referencing core module
3804 * data, which is OK.
3805 */
3806 if (!iter->ent)
3807 return false;
3808
3809 trace_event = ftrace_find_event(iter->ent->type);
3810 if (!trace_event)
3811 return false;
3812
3813 event = container_of(trace_event, struct trace_event_call, event);
3814 if ((event->flags & TRACE_EVENT_FL_DYNAMIC) || !event->module)
3815 return false;
3816
3817 /* Would rather have rodata, but this will suffice */
3818 if (within_module_core(addr, event->module))
3819 return true;
3820
3821 return false;
3822}
3823
3824static DEFINE_STATIC_KEY_FALSE(trace_no_verify);
3825
3826static int test_can_verify_check(const char *fmt, ...)
3827{
3828 char buf[16];
3829 va_list ap;
3830 int ret;
3831
3832 /*
3833 * The verifier is dependent on vsnprintf() modifies the va_list
3834 * passed to it, where it is sent as a reference. Some architectures
3835 * (like x86_32) passes it by value, which means that vsnprintf()
3836 * does not modify the va_list passed to it, and the verifier
3837 * would then need to be able to understand all the values that
3838 * vsnprintf can use. If it is passed by value, then the verifier
3839 * is disabled.
3840 */
3841 va_start(ap, fmt);
3842 vsnprintf(buf, 16, "%d", ap);
3843 ret = va_arg(ap, int);
3844 va_end(ap);
3845
3846 return ret;
3847}
3848
3849static void test_can_verify(void)
3850{
3851 if (!test_can_verify_check("%d %d", 0, 1)) {
3852 pr_info("trace event string verifier disabled\n");
3853 static_branch_inc(&trace_no_verify);
3854 }
3855}
3856
3857/**
3858 * trace_check_vprintf - Check dereferenced strings while writing to the seq buffer
3859 * @iter: The iterator that holds the seq buffer and the event being printed
3860 * @fmt: The format used to print the event
3861 * @ap: The va_list holding the data to print from @fmt.
3862 *
3863 * This writes the data into the @iter->seq buffer using the data from
3864 * @fmt and @ap. If the format has a %s, then the source of the string
3865 * is examined to make sure it is safe to print, otherwise it will
3866 * warn and print "[UNSAFE MEMORY]" in place of the dereferenced string
3867 * pointer.
3868 */
3869void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
3870 va_list ap)
3871{
3872 const char *p = fmt;
3873 const char *str;
3874 int i, j;
3875
3876 if (WARN_ON_ONCE(!fmt))
3877 return;
3878
3879 if (static_branch_unlikely(&trace_no_verify))
3880 goto print;
3881
3882 /* Don't bother checking when doing a ftrace_dump() */
3883 if (iter->fmt == static_fmt_buf)
3884 goto print;
3885
3886 while (*p) {
3887 bool star = false;
3888 int len = 0;
3889
3890 j = 0;
3891
3892 /* We only care about %s and variants */
3893 for (i = 0; p[i]; i++) {
3894 if (i + 1 >= iter->fmt_size) {
3895 /*
3896 * If we can't expand the copy buffer,
3897 * just print it.
3898 */
3899 if (!trace_iter_expand_format(iter))
3900 goto print;
3901 }
3902
3903 if (p[i] == '\\' && p[i+1]) {
3904 i++;
3905 continue;
3906 }
3907 if (p[i] == '%') {
3908 /* Need to test cases like %08.*s */
3909 for (j = 1; p[i+j]; j++) {
3910 if (isdigit(p[i+j]) ||
3911 p[i+j] == '.')
3912 continue;
3913 if (p[i+j] == '*') {
3914 star = true;
3915 continue;
3916 }
3917 break;
3918 }
3919 if (p[i+j] == 's')
3920 break;
3921 star = false;
3922 }
3923 j = 0;
3924 }
3925 /* If no %s found then just print normally */
3926 if (!p[i])
3927 break;
3928
3929 /* Copy up to the %s, and print that */
3930 strncpy(iter->fmt, p, i);
3931 iter->fmt[i] = '\0';
3932 trace_seq_vprintf(&iter->seq, iter->fmt, ap);
3933
3934 /*
3935 * If iter->seq is full, the above call no longer guarantees
3936 * that ap is in sync with fmt processing, and further calls
3937 * to va_arg() can return wrong positional arguments.
3938 *
3939 * Ensure that ap is no longer used in this case.
3940 */
3941 if (iter->seq.full) {
3942 p = "";
3943 break;
3944 }
3945
3946 if (star)
3947 len = va_arg(ap, int);
3948
3949 /* The ap now points to the string data of the %s */
3950 str = va_arg(ap, const char *);
3951
3952 /*
3953 * If you hit this warning, it is likely that the
3954 * trace event in question used %s on a string that
3955 * was saved at the time of the event, but may not be
3956 * around when the trace is read. Use __string(),
3957 * __assign_str() and __get_str() helpers in the TRACE_EVENT()
3958 * instead. See samples/trace_events/trace-events-sample.h
3959 * for reference.
3960 */
3961 if (WARN_ONCE(!trace_safe_str(iter, str, star, len),
3962 "fmt: '%s' current_buffer: '%s'",
3963 fmt, seq_buf_str(&iter->seq.seq))) {
3964 int ret;
3965
3966 /* Try to safely read the string */
3967 if (star) {
3968 if (len + 1 > iter->fmt_size)
3969 len = iter->fmt_size - 1;
3970 if (len < 0)
3971 len = 0;
3972 ret = copy_from_kernel_nofault(iter->fmt, str, len);
3973 iter->fmt[len] = 0;
3974 star = false;
3975 } else {
3976 ret = strncpy_from_kernel_nofault(iter->fmt, str,
3977 iter->fmt_size);
3978 }
3979 if (ret < 0)
3980 trace_seq_printf(&iter->seq, "(0x%px)", str);
3981 else
3982 trace_seq_printf(&iter->seq, "(0x%px:%s)",
3983 str, iter->fmt);
3984 str = "[UNSAFE-MEMORY]";
3985 strcpy(iter->fmt, "%s");
3986 } else {
3987 strncpy(iter->fmt, p + i, j + 1);
3988 iter->fmt[j+1] = '\0';
3989 }
3990 if (star)
3991 trace_seq_printf(&iter->seq, iter->fmt, len, str);
3992 else
3993 trace_seq_printf(&iter->seq, iter->fmt, str);
3994
3995 p += i + j + 1;
3996 }
3997 print:
3998 if (*p)
3999 trace_seq_vprintf(&iter->seq, p, ap);
4000}
4001
4002const char *trace_event_format(struct trace_iterator *iter, const char *fmt)
4003{
4004 const char *p, *new_fmt;
4005 char *q;
4006
4007 if (WARN_ON_ONCE(!fmt))
4008 return fmt;
4009
4010 if (!iter->tr || iter->tr->trace_flags & TRACE_ITER_HASH_PTR)
4011 return fmt;
4012
4013 p = fmt;
4014 new_fmt = q = iter->fmt;
4015 while (*p) {
4016 if (unlikely(q - new_fmt + 3 > iter->fmt_size)) {
4017 if (!trace_iter_expand_format(iter))
4018 return fmt;
4019
4020 q += iter->fmt - new_fmt;
4021 new_fmt = iter->fmt;
4022 }
4023
4024 *q++ = *p++;
4025
4026 /* Replace %p with %px */
4027 if (p[-1] == '%') {
4028 if (p[0] == '%') {
4029 *q++ = *p++;
4030 } else if (p[0] == 'p' && !isalnum(p[1])) {
4031 *q++ = *p++;
4032 *q++ = 'x';
4033 }
4034 }
4035 }
4036 *q = '\0';
4037
4038 return new_fmt;
4039}
4040
4041#define STATIC_TEMP_BUF_SIZE 128
4042static char static_temp_buf[STATIC_TEMP_BUF_SIZE] __aligned(4);
4043
4044/* Find the next real entry, without updating the iterator itself */
4045struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
4046 int *ent_cpu, u64 *ent_ts)
4047{
4048 /* __find_next_entry will reset ent_size */
4049 int ent_size = iter->ent_size;
4050 struct trace_entry *entry;
4051
4052 /*
4053 * If called from ftrace_dump(), then the iter->temp buffer
4054 * will be the static_temp_buf and not created from kmalloc.
4055 * If the entry size is greater than the buffer, we can
4056 * not save it. Just return NULL in that case. This is only
4057 * used to add markers when two consecutive events' time
4058 * stamps have a large delta. See trace_print_lat_context()
4059 */
4060 if (iter->temp == static_temp_buf &&
4061 STATIC_TEMP_BUF_SIZE < ent_size)
4062 return NULL;
4063
4064 /*
4065 * The __find_next_entry() may call peek_next_entry(), which may
4066 * call ring_buffer_peek() that may make the contents of iter->ent
4067 * undefined. Need to copy iter->ent now.
4068 */
4069 if (iter->ent && iter->ent != iter->temp) {
4070 if ((!iter->temp || iter->temp_size < iter->ent_size) &&
4071 !WARN_ON_ONCE(iter->temp == static_temp_buf)) {
4072 void *temp;
4073 temp = kmalloc(iter->ent_size, GFP_KERNEL);
4074 if (!temp)
4075 return NULL;
4076 kfree(iter->temp);
4077 iter->temp = temp;
4078 iter->temp_size = iter->ent_size;
4079 }
4080 memcpy(iter->temp, iter->ent, iter->ent_size);
4081 iter->ent = iter->temp;
4082 }
4083 entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);
4084 /* Put back the original ent_size */
4085 iter->ent_size = ent_size;
4086
4087 return entry;
4088}
4089
4090/* Find the next real entry, and increment the iterator to the next entry */
4091void *trace_find_next_entry_inc(struct trace_iterator *iter)
4092{
4093 iter->ent = __find_next_entry(iter, &iter->cpu,
4094 &iter->lost_events, &iter->ts);
4095
4096 if (iter->ent)
4097 trace_iterator_increment(iter);
4098
4099 return iter->ent ? iter : NULL;
4100}
4101
4102static void trace_consume(struct trace_iterator *iter)
4103{
4104 ring_buffer_consume(iter->array_buffer->buffer, iter->cpu, &iter->ts,
4105 &iter->lost_events);
4106}
4107
4108static void *s_next(struct seq_file *m, void *v, loff_t *pos)
4109{
4110 struct trace_iterator *iter = m->private;
4111 int i = (int)*pos;
4112 void *ent;
4113
4114 WARN_ON_ONCE(iter->leftover);
4115
4116 (*pos)++;
4117
4118 /* can't go backwards */
4119 if (iter->idx > i)
4120 return NULL;
4121
4122 if (iter->idx < 0)
4123 ent = trace_find_next_entry_inc(iter);
4124 else
4125 ent = iter;
4126
4127 while (ent && iter->idx < i)
4128 ent = trace_find_next_entry_inc(iter);
4129
4130 iter->pos = *pos;
4131
4132 return ent;
4133}
4134
4135void tracing_iter_reset(struct trace_iterator *iter, int cpu)
4136{
4137 struct ring_buffer_iter *buf_iter;
4138 unsigned long entries = 0;
4139 u64 ts;
4140
4141 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = 0;
4142
4143 buf_iter = trace_buffer_iter(iter, cpu);
4144 if (!buf_iter)
4145 return;
4146
4147 ring_buffer_iter_reset(buf_iter);
4148
4149 /*
4150 * We could have the case with the max latency tracers
4151 * that a reset never took place on a cpu. This is evident
4152 * by the timestamp being before the start of the buffer.
4153 */
4154 while (ring_buffer_iter_peek(buf_iter, &ts)) {
4155 if (ts >= iter->array_buffer->time_start)
4156 break;
4157 entries++;
4158 ring_buffer_iter_advance(buf_iter);
4159 }
4160
4161 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = entries;
4162}
4163
4164/*
4165 * The current tracer is copied to avoid a global locking
4166 * all around.
4167 */
4168static void *s_start(struct seq_file *m, loff_t *pos)
4169{
4170 struct trace_iterator *iter = m->private;
4171 struct trace_array *tr = iter->tr;
4172 int cpu_file = iter->cpu_file;
4173 void *p = NULL;
4174 loff_t l = 0;
4175 int cpu;
4176
4177 mutex_lock(&trace_types_lock);
4178 if (unlikely(tr->current_trace != iter->trace)) {
4179 /* Close iter->trace before switching to the new current tracer */
4180 if (iter->trace->close)
4181 iter->trace->close(iter);
4182 iter->trace = tr->current_trace;
4183 /* Reopen the new current tracer */
4184 if (iter->trace->open)
4185 iter->trace->open(iter);
4186 }
4187 mutex_unlock(&trace_types_lock);
4188
4189#ifdef CONFIG_TRACER_MAX_TRACE
4190 if (iter->snapshot && iter->trace->use_max_tr)
4191 return ERR_PTR(-EBUSY);
4192#endif
4193
4194 if (*pos != iter->pos) {
4195 iter->ent = NULL;
4196 iter->cpu = 0;
4197 iter->idx = -1;
4198
4199 if (cpu_file == RING_BUFFER_ALL_CPUS) {
4200 for_each_tracing_cpu(cpu)
4201 tracing_iter_reset(iter, cpu);
4202 } else
4203 tracing_iter_reset(iter, cpu_file);
4204
4205 iter->leftover = 0;
4206 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
4207 ;
4208
4209 } else {
4210 /*
4211 * If we overflowed the seq_file before, then we want
4212 * to just reuse the trace_seq buffer again.
4213 */
4214 if (iter->leftover)
4215 p = iter;
4216 else {
4217 l = *pos - 1;
4218 p = s_next(m, p, &l);
4219 }
4220 }
4221
4222 trace_event_read_lock();
4223 trace_access_lock(cpu_file);
4224 return p;
4225}
4226
4227static void s_stop(struct seq_file *m, void *p)
4228{
4229 struct trace_iterator *iter = m->private;
4230
4231#ifdef CONFIG_TRACER_MAX_TRACE
4232 if (iter->snapshot && iter->trace->use_max_tr)
4233 return;
4234#endif
4235
4236 trace_access_unlock(iter->cpu_file);
4237 trace_event_read_unlock();
4238}
4239
4240static void
4241get_total_entries_cpu(struct array_buffer *buf, unsigned long *total,
4242 unsigned long *entries, int cpu)
4243{
4244 unsigned long count;
4245
4246 count = ring_buffer_entries_cpu(buf->buffer, cpu);
4247 /*
4248 * If this buffer has skipped entries, then we hold all
4249 * entries for the trace and we need to ignore the
4250 * ones before the time stamp.
4251 */
4252 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
4253 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
4254 /* total is the same as the entries */
4255 *total = count;
4256 } else
4257 *total = count +
4258 ring_buffer_overrun_cpu(buf->buffer, cpu);
4259 *entries = count;
4260}
4261
4262static void
4263get_total_entries(struct array_buffer *buf,
4264 unsigned long *total, unsigned long *entries)
4265{
4266 unsigned long t, e;
4267 int cpu;
4268
4269 *total = 0;
4270 *entries = 0;
4271
4272 for_each_tracing_cpu(cpu) {
4273 get_total_entries_cpu(buf, &t, &e, cpu);
4274 *total += t;
4275 *entries += e;
4276 }
4277}
4278
4279unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
4280{
4281 unsigned long total, entries;
4282
4283 if (!tr)
4284 tr = &global_trace;
4285
4286 get_total_entries_cpu(&tr->array_buffer, &total, &entries, cpu);
4287
4288 return entries;
4289}
4290
4291unsigned long trace_total_entries(struct trace_array *tr)
4292{
4293 unsigned long total, entries;
4294
4295 if (!tr)
4296 tr = &global_trace;
4297
4298 get_total_entries(&tr->array_buffer, &total, &entries);
4299
4300 return entries;
4301}
4302
4303static void print_lat_help_header(struct seq_file *m)
4304{
4305 seq_puts(m, "# _------=> CPU# \n"
4306 "# / _-----=> irqs-off/BH-disabled\n"
4307 "# | / _----=> need-resched \n"
4308 "# || / _---=> hardirq/softirq \n"
4309 "# ||| / _--=> preempt-depth \n"
4310 "# |||| / _-=> migrate-disable \n"
4311 "# ||||| / delay \n"
4312 "# cmd pid |||||| time | caller \n"
4313 "# \\ / |||||| \\ | / \n");
4314}
4315
4316static void print_event_info(struct array_buffer *buf, struct seq_file *m)
4317{
4318 unsigned long total;
4319 unsigned long entries;
4320
4321 get_total_entries(buf, &total, &entries);
4322 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
4323 entries, total, num_online_cpus());
4324 seq_puts(m, "#\n");
4325}
4326
4327static void print_func_help_header(struct array_buffer *buf, struct seq_file *m,
4328 unsigned int flags)
4329{
4330 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4331
4332 print_event_info(buf, m);
4333
4334 seq_printf(m, "# TASK-PID %s CPU# TIMESTAMP FUNCTION\n", tgid ? " TGID " : "");
4335 seq_printf(m, "# | | %s | | |\n", tgid ? " | " : "");
4336}
4337
4338static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file *m,
4339 unsigned int flags)
4340{
4341 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4342 static const char space[] = " ";
4343 int prec = tgid ? 12 : 2;
4344
4345 print_event_info(buf, m);
4346
4347 seq_printf(m, "# %.*s _-----=> irqs-off/BH-disabled\n", prec, space);
4348 seq_printf(m, "# %.*s / _----=> need-resched\n", prec, space);
4349 seq_printf(m, "# %.*s| / _---=> hardirq/softirq\n", prec, space);
4350 seq_printf(m, "# %.*s|| / _--=> preempt-depth\n", prec, space);
4351 seq_printf(m, "# %.*s||| / _-=> migrate-disable\n", prec, space);
4352 seq_printf(m, "# %.*s|||| / delay\n", prec, space);
4353 seq_printf(m, "# TASK-PID %.*s CPU# ||||| TIMESTAMP FUNCTION\n", prec, " TGID ");
4354 seq_printf(m, "# | | %.*s | ||||| | |\n", prec, " | ");
4355}
4356
4357void
4358print_trace_header(struct seq_file *m, struct trace_iterator *iter)
4359{
4360 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
4361 struct array_buffer *buf = iter->array_buffer;
4362 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
4363 struct tracer *type = iter->trace;
4364 unsigned long entries;
4365 unsigned long total;
4366 const char *name = type->name;
4367
4368 get_total_entries(buf, &total, &entries);
4369
4370 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
4371 name, UTS_RELEASE);
4372 seq_puts(m, "# -----------------------------------"
4373 "---------------------------------\n");
4374 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
4375 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
4376 nsecs_to_usecs(data->saved_latency),
4377 entries,
4378 total,
4379 buf->cpu,
4380 preempt_model_none() ? "server" :
4381 preempt_model_voluntary() ? "desktop" :
4382 preempt_model_full() ? "preempt" :
4383 preempt_model_rt() ? "preempt_rt" :
4384 "unknown",
4385 /* These are reserved for later use */
4386 0, 0, 0, 0);
4387#ifdef CONFIG_SMP
4388 seq_printf(m, " #P:%d)\n", num_online_cpus());
4389#else
4390 seq_puts(m, ")\n");
4391#endif
4392 seq_puts(m, "# -----------------\n");
4393 seq_printf(m, "# | task: %.16s-%d "
4394 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
4395 data->comm, data->pid,
4396 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
4397 data->policy, data->rt_priority);
4398 seq_puts(m, "# -----------------\n");
4399
4400 if (data->critical_start) {
4401 seq_puts(m, "# => started at: ");
4402 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
4403 trace_print_seq(m, &iter->seq);
4404 seq_puts(m, "\n# => ended at: ");
4405 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
4406 trace_print_seq(m, &iter->seq);
4407 seq_puts(m, "\n#\n");
4408 }
4409
4410 seq_puts(m, "#\n");
4411}
4412
4413static void test_cpu_buff_start(struct trace_iterator *iter)
4414{
4415 struct trace_seq *s = &iter->seq;
4416 struct trace_array *tr = iter->tr;
4417
4418 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
4419 return;
4420
4421 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
4422 return;
4423
4424 if (cpumask_available(iter->started) &&
4425 cpumask_test_cpu(iter->cpu, iter->started))
4426 return;
4427
4428 if (per_cpu_ptr(iter->array_buffer->data, iter->cpu)->skipped_entries)
4429 return;
4430
4431 if (cpumask_available(iter->started))
4432 cpumask_set_cpu(iter->cpu, iter->started);
4433
4434 /* Don't print started cpu buffer for the first entry of the trace */
4435 if (iter->idx > 1)
4436 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
4437 iter->cpu);
4438}
4439
4440static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
4441{
4442 struct trace_array *tr = iter->tr;
4443 struct trace_seq *s = &iter->seq;
4444 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
4445 struct trace_entry *entry;
4446 struct trace_event *event;
4447
4448 entry = iter->ent;
4449
4450 test_cpu_buff_start(iter);
4451
4452 event = ftrace_find_event(entry->type);
4453
4454 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4455 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4456 trace_print_lat_context(iter);
4457 else
4458 trace_print_context(iter);
4459 }
4460
4461 if (trace_seq_has_overflowed(s))
4462 return TRACE_TYPE_PARTIAL_LINE;
4463
4464 if (event) {
4465 if (tr->trace_flags & TRACE_ITER_FIELDS)
4466 return print_event_fields(iter, event);
4467 return event->funcs->trace(iter, sym_flags, event);
4468 }
4469
4470 trace_seq_printf(s, "Unknown type %d\n", entry->type);
4471
4472 return trace_handle_return(s);
4473}
4474
4475static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
4476{
4477 struct trace_array *tr = iter->tr;
4478 struct trace_seq *s = &iter->seq;
4479 struct trace_entry *entry;
4480 struct trace_event *event;
4481
4482 entry = iter->ent;
4483
4484 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
4485 trace_seq_printf(s, "%d %d %llu ",
4486 entry->pid, iter->cpu, iter->ts);
4487
4488 if (trace_seq_has_overflowed(s))
4489 return TRACE_TYPE_PARTIAL_LINE;
4490
4491 event = ftrace_find_event(entry->type);
4492 if (event)
4493 return event->funcs->raw(iter, 0, event);
4494
4495 trace_seq_printf(s, "%d ?\n", entry->type);
4496
4497 return trace_handle_return(s);
4498}
4499
4500static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
4501{
4502 struct trace_array *tr = iter->tr;
4503 struct trace_seq *s = &iter->seq;
4504 unsigned char newline = '\n';
4505 struct trace_entry *entry;
4506 struct trace_event *event;
4507
4508 entry = iter->ent;
4509
4510 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4511 SEQ_PUT_HEX_FIELD(s, entry->pid);
4512 SEQ_PUT_HEX_FIELD(s, iter->cpu);
4513 SEQ_PUT_HEX_FIELD(s, iter->ts);
4514 if (trace_seq_has_overflowed(s))
4515 return TRACE_TYPE_PARTIAL_LINE;
4516 }
4517
4518 event = ftrace_find_event(entry->type);
4519 if (event) {
4520 enum print_line_t ret = event->funcs->hex(iter, 0, event);
4521 if (ret != TRACE_TYPE_HANDLED)
4522 return ret;
4523 }
4524
4525 SEQ_PUT_FIELD(s, newline);
4526
4527 return trace_handle_return(s);
4528}
4529
4530static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
4531{
4532 struct trace_array *tr = iter->tr;
4533 struct trace_seq *s = &iter->seq;
4534 struct trace_entry *entry;
4535 struct trace_event *event;
4536
4537 entry = iter->ent;
4538
4539 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4540 SEQ_PUT_FIELD(s, entry->pid);
4541 SEQ_PUT_FIELD(s, iter->cpu);
4542 SEQ_PUT_FIELD(s, iter->ts);
4543 if (trace_seq_has_overflowed(s))
4544 return TRACE_TYPE_PARTIAL_LINE;
4545 }
4546
4547 event = ftrace_find_event(entry->type);
4548 return event ? event->funcs->binary(iter, 0, event) :
4549 TRACE_TYPE_HANDLED;
4550}
4551
4552int trace_empty(struct trace_iterator *iter)
4553{
4554 struct ring_buffer_iter *buf_iter;
4555 int cpu;
4556
4557 /* If we are looking at one CPU buffer, only check that one */
4558 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4559 cpu = iter->cpu_file;
4560 buf_iter = trace_buffer_iter(iter, cpu);
4561 if (buf_iter) {
4562 if (!ring_buffer_iter_empty(buf_iter))
4563 return 0;
4564 } else {
4565 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4566 return 0;
4567 }
4568 return 1;
4569 }
4570
4571 for_each_tracing_cpu(cpu) {
4572 buf_iter = trace_buffer_iter(iter, cpu);
4573 if (buf_iter) {
4574 if (!ring_buffer_iter_empty(buf_iter))
4575 return 0;
4576 } else {
4577 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4578 return 0;
4579 }
4580 }
4581
4582 return 1;
4583}
4584
4585/* Called with trace_event_read_lock() held. */
4586enum print_line_t print_trace_line(struct trace_iterator *iter)
4587{
4588 struct trace_array *tr = iter->tr;
4589 unsigned long trace_flags = tr->trace_flags;
4590 enum print_line_t ret;
4591
4592 if (iter->lost_events) {
4593 if (iter->lost_events == (unsigned long)-1)
4594 trace_seq_printf(&iter->seq, "CPU:%d [LOST EVENTS]\n",
4595 iter->cpu);
4596 else
4597 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
4598 iter->cpu, iter->lost_events);
4599 if (trace_seq_has_overflowed(&iter->seq))
4600 return TRACE_TYPE_PARTIAL_LINE;
4601 }
4602
4603 if (iter->trace && iter->trace->print_line) {
4604 ret = iter->trace->print_line(iter);
4605 if (ret != TRACE_TYPE_UNHANDLED)
4606 return ret;
4607 }
4608
4609 if (iter->ent->type == TRACE_BPUTS &&
4610 trace_flags & TRACE_ITER_PRINTK &&
4611 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4612 return trace_print_bputs_msg_only(iter);
4613
4614 if (iter->ent->type == TRACE_BPRINT &&
4615 trace_flags & TRACE_ITER_PRINTK &&
4616 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4617 return trace_print_bprintk_msg_only(iter);
4618
4619 if (iter->ent->type == TRACE_PRINT &&
4620 trace_flags & TRACE_ITER_PRINTK &&
4621 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4622 return trace_print_printk_msg_only(iter);
4623
4624 if (trace_flags & TRACE_ITER_BIN)
4625 return print_bin_fmt(iter);
4626
4627 if (trace_flags & TRACE_ITER_HEX)
4628 return print_hex_fmt(iter);
4629
4630 if (trace_flags & TRACE_ITER_RAW)
4631 return print_raw_fmt(iter);
4632
4633 return print_trace_fmt(iter);
4634}
4635
4636void trace_latency_header(struct seq_file *m)
4637{
4638 struct trace_iterator *iter = m->private;
4639 struct trace_array *tr = iter->tr;
4640
4641 /* print nothing if the buffers are empty */
4642 if (trace_empty(iter))
4643 return;
4644
4645 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4646 print_trace_header(m, iter);
4647
4648 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
4649 print_lat_help_header(m);
4650}
4651
4652void trace_default_header(struct seq_file *m)
4653{
4654 struct trace_iterator *iter = m->private;
4655 struct trace_array *tr = iter->tr;
4656 unsigned long trace_flags = tr->trace_flags;
4657
4658 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
4659 return;
4660
4661 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
4662 /* print nothing if the buffers are empty */
4663 if (trace_empty(iter))
4664 return;
4665 print_trace_header(m, iter);
4666 if (!(trace_flags & TRACE_ITER_VERBOSE))
4667 print_lat_help_header(m);
4668 } else {
4669 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
4670 if (trace_flags & TRACE_ITER_IRQ_INFO)
4671 print_func_help_header_irq(iter->array_buffer,
4672 m, trace_flags);
4673 else
4674 print_func_help_header(iter->array_buffer, m,
4675 trace_flags);
4676 }
4677 }
4678}
4679
4680static void test_ftrace_alive(struct seq_file *m)
4681{
4682 if (!ftrace_is_dead())
4683 return;
4684 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
4685 "# MAY BE MISSING FUNCTION EVENTS\n");
4686}
4687
4688#ifdef CONFIG_TRACER_MAX_TRACE
4689static void show_snapshot_main_help(struct seq_file *m)
4690{
4691 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
4692 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4693 "# Takes a snapshot of the main buffer.\n"
4694 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
4695 "# (Doesn't have to be '2' works with any number that\n"
4696 "# is not a '0' or '1')\n");
4697}
4698
4699static void show_snapshot_percpu_help(struct seq_file *m)
4700{
4701 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
4702#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
4703 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4704 "# Takes a snapshot of the main buffer for this cpu.\n");
4705#else
4706 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
4707 "# Must use main snapshot file to allocate.\n");
4708#endif
4709 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
4710 "# (Doesn't have to be '2' works with any number that\n"
4711 "# is not a '0' or '1')\n");
4712}
4713
4714static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
4715{
4716 if (iter->tr->allocated_snapshot)
4717 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
4718 else
4719 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
4720
4721 seq_puts(m, "# Snapshot commands:\n");
4722 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4723 show_snapshot_main_help(m);
4724 else
4725 show_snapshot_percpu_help(m);
4726}
4727#else
4728/* Should never be called */
4729static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
4730#endif
4731
4732static int s_show(struct seq_file *m, void *v)
4733{
4734 struct trace_iterator *iter = v;
4735 int ret;
4736
4737 if (iter->ent == NULL) {
4738 if (iter->tr) {
4739 seq_printf(m, "# tracer: %s\n", iter->trace->name);
4740 seq_puts(m, "#\n");
4741 test_ftrace_alive(m);
4742 }
4743 if (iter->snapshot && trace_empty(iter))
4744 print_snapshot_help(m, iter);
4745 else if (iter->trace && iter->trace->print_header)
4746 iter->trace->print_header(m);
4747 else
4748 trace_default_header(m);
4749
4750 } else if (iter->leftover) {
4751 /*
4752 * If we filled the seq_file buffer earlier, we
4753 * want to just show it now.
4754 */
4755 ret = trace_print_seq(m, &iter->seq);
4756
4757 /* ret should this time be zero, but you never know */
4758 iter->leftover = ret;
4759
4760 } else {
4761 ret = print_trace_line(iter);
4762 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4763 iter->seq.full = 0;
4764 trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
4765 }
4766 ret = trace_print_seq(m, &iter->seq);
4767 /*
4768 * If we overflow the seq_file buffer, then it will
4769 * ask us for this data again at start up.
4770 * Use that instead.
4771 * ret is 0 if seq_file write succeeded.
4772 * -1 otherwise.
4773 */
4774 iter->leftover = ret;
4775 }
4776
4777 return 0;
4778}
4779
4780/*
4781 * Should be used after trace_array_get(), trace_types_lock
4782 * ensures that i_cdev was already initialized.
4783 */
4784static inline int tracing_get_cpu(struct inode *inode)
4785{
4786 if (inode->i_cdev) /* See trace_create_cpu_file() */
4787 return (long)inode->i_cdev - 1;
4788 return RING_BUFFER_ALL_CPUS;
4789}
4790
4791static const struct seq_operations tracer_seq_ops = {
4792 .start = s_start,
4793 .next = s_next,
4794 .stop = s_stop,
4795 .show = s_show,
4796};
4797
4798/*
4799 * Note, as iter itself can be allocated and freed in different
4800 * ways, this function is only used to free its content, and not
4801 * the iterator itself. The only requirement to all the allocations
4802 * is that it must zero all fields (kzalloc), as freeing works with
4803 * ethier allocated content or NULL.
4804 */
4805static void free_trace_iter_content(struct trace_iterator *iter)
4806{
4807 /* The fmt is either NULL, allocated or points to static_fmt_buf */
4808 if (iter->fmt != static_fmt_buf)
4809 kfree(iter->fmt);
4810
4811 kfree(iter->temp);
4812 kfree(iter->buffer_iter);
4813 mutex_destroy(&iter->mutex);
4814 free_cpumask_var(iter->started);
4815}
4816
4817static struct trace_iterator *
4818__tracing_open(struct inode *inode, struct file *file, bool snapshot)
4819{
4820 struct trace_array *tr = inode->i_private;
4821 struct trace_iterator *iter;
4822 int cpu;
4823
4824 if (tracing_disabled)
4825 return ERR_PTR(-ENODEV);
4826
4827 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
4828 if (!iter)
4829 return ERR_PTR(-ENOMEM);
4830
4831 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
4832 GFP_KERNEL);
4833 if (!iter->buffer_iter)
4834 goto release;
4835
4836 /*
4837 * trace_find_next_entry() may need to save off iter->ent.
4838 * It will place it into the iter->temp buffer. As most
4839 * events are less than 128, allocate a buffer of that size.
4840 * If one is greater, then trace_find_next_entry() will
4841 * allocate a new buffer to adjust for the bigger iter->ent.
4842 * It's not critical if it fails to get allocated here.
4843 */
4844 iter->temp = kmalloc(128, GFP_KERNEL);
4845 if (iter->temp)
4846 iter->temp_size = 128;
4847
4848 /*
4849 * trace_event_printf() may need to modify given format
4850 * string to replace %p with %px so that it shows real address
4851 * instead of hash value. However, that is only for the event
4852 * tracing, other tracer may not need. Defer the allocation
4853 * until it is needed.
4854 */
4855 iter->fmt = NULL;
4856 iter->fmt_size = 0;
4857
4858 mutex_lock(&trace_types_lock);
4859 iter->trace = tr->current_trace;
4860
4861 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
4862 goto fail;
4863
4864 iter->tr = tr;
4865
4866#ifdef CONFIG_TRACER_MAX_TRACE
4867 /* Currently only the top directory has a snapshot */
4868 if (tr->current_trace->print_max || snapshot)
4869 iter->array_buffer = &tr->max_buffer;
4870 else
4871#endif
4872 iter->array_buffer = &tr->array_buffer;
4873 iter->snapshot = snapshot;
4874 iter->pos = -1;
4875 iter->cpu_file = tracing_get_cpu(inode);
4876 mutex_init(&iter->mutex);
4877
4878 /* Notify the tracer early; before we stop tracing. */
4879 if (iter->trace->open)
4880 iter->trace->open(iter);
4881
4882 /* Annotate start of buffers if we had overruns */
4883 if (ring_buffer_overruns(iter->array_buffer->buffer))
4884 iter->iter_flags |= TRACE_FILE_ANNOTATE;
4885
4886 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4887 if (trace_clocks[tr->clock_id].in_ns)
4888 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4889
4890 /*
4891 * If pause-on-trace is enabled, then stop the trace while
4892 * dumping, unless this is the "snapshot" file
4893 */
4894 if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE))
4895 tracing_stop_tr(tr);
4896
4897 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
4898 for_each_tracing_cpu(cpu) {
4899 iter->buffer_iter[cpu] =
4900 ring_buffer_read_prepare(iter->array_buffer->buffer,
4901 cpu, GFP_KERNEL);
4902 }
4903 ring_buffer_read_prepare_sync();
4904 for_each_tracing_cpu(cpu) {
4905 ring_buffer_read_start(iter->buffer_iter[cpu]);
4906 tracing_iter_reset(iter, cpu);
4907 }
4908 } else {
4909 cpu = iter->cpu_file;
4910 iter->buffer_iter[cpu] =
4911 ring_buffer_read_prepare(iter->array_buffer->buffer,
4912 cpu, GFP_KERNEL);
4913 ring_buffer_read_prepare_sync();
4914 ring_buffer_read_start(iter->buffer_iter[cpu]);
4915 tracing_iter_reset(iter, cpu);
4916 }
4917
4918 mutex_unlock(&trace_types_lock);
4919
4920 return iter;
4921
4922 fail:
4923 mutex_unlock(&trace_types_lock);
4924 free_trace_iter_content(iter);
4925release:
4926 seq_release_private(inode, file);
4927 return ERR_PTR(-ENOMEM);
4928}
4929
4930int tracing_open_generic(struct inode *inode, struct file *filp)
4931{
4932 int ret;
4933
4934 ret = tracing_check_open_get_tr(NULL);
4935 if (ret)
4936 return ret;
4937
4938 filp->private_data = inode->i_private;
4939 return 0;
4940}
4941
4942bool tracing_is_disabled(void)
4943{
4944 return (tracing_disabled) ? true: false;
4945}
4946
4947/*
4948 * Open and update trace_array ref count.
4949 * Must have the current trace_array passed to it.
4950 */
4951int tracing_open_generic_tr(struct inode *inode, struct file *filp)
4952{
4953 struct trace_array *tr = inode->i_private;
4954 int ret;
4955
4956 ret = tracing_check_open_get_tr(tr);
4957 if (ret)
4958 return ret;
4959
4960 filp->private_data = inode->i_private;
4961
4962 return 0;
4963}
4964
4965/*
4966 * The private pointer of the inode is the trace_event_file.
4967 * Update the tr ref count associated to it.
4968 */
4969int tracing_open_file_tr(struct inode *inode, struct file *filp)
4970{
4971 struct trace_event_file *file = inode->i_private;
4972 int ret;
4973
4974 ret = tracing_check_open_get_tr(file->tr);
4975 if (ret)
4976 return ret;
4977
4978 mutex_lock(&event_mutex);
4979
4980 /* Fail if the file is marked for removal */
4981 if (file->flags & EVENT_FILE_FL_FREED) {
4982 trace_array_put(file->tr);
4983 ret = -ENODEV;
4984 } else {
4985 event_file_get(file);
4986 }
4987
4988 mutex_unlock(&event_mutex);
4989 if (ret)
4990 return ret;
4991
4992 filp->private_data = inode->i_private;
4993
4994 return 0;
4995}
4996
4997int tracing_release_file_tr(struct inode *inode, struct file *filp)
4998{
4999 struct trace_event_file *file = inode->i_private;
5000
5001 trace_array_put(file->tr);
5002 event_file_put(file);
5003
5004 return 0;
5005}
5006
5007int tracing_single_release_file_tr(struct inode *inode, struct file *filp)
5008{
5009 tracing_release_file_tr(inode, filp);
5010 return single_release(inode, filp);
5011}
5012
5013static int tracing_mark_open(struct inode *inode, struct file *filp)
5014{
5015 stream_open(inode, filp);
5016 return tracing_open_generic_tr(inode, filp);
5017}
5018
5019static int tracing_release(struct inode *inode, struct file *file)
5020{
5021 struct trace_array *tr = inode->i_private;
5022 struct seq_file *m = file->private_data;
5023 struct trace_iterator *iter;
5024 int cpu;
5025
5026 if (!(file->f_mode & FMODE_READ)) {
5027 trace_array_put(tr);
5028 return 0;
5029 }
5030
5031 /* Writes do not use seq_file */
5032 iter = m->private;
5033 mutex_lock(&trace_types_lock);
5034
5035 for_each_tracing_cpu(cpu) {
5036 if (iter->buffer_iter[cpu])
5037 ring_buffer_read_finish(iter->buffer_iter[cpu]);
5038 }
5039
5040 if (iter->trace && iter->trace->close)
5041 iter->trace->close(iter);
5042
5043 if (!iter->snapshot && tr->stop_count)
5044 /* reenable tracing if it was previously enabled */
5045 tracing_start_tr(tr);
5046
5047 __trace_array_put(tr);
5048
5049 mutex_unlock(&trace_types_lock);
5050
5051 free_trace_iter_content(iter);
5052 seq_release_private(inode, file);
5053
5054 return 0;
5055}
5056
5057int tracing_release_generic_tr(struct inode *inode, struct file *file)
5058{
5059 struct trace_array *tr = inode->i_private;
5060
5061 trace_array_put(tr);
5062 return 0;
5063}
5064
5065static int tracing_single_release_tr(struct inode *inode, struct file *file)
5066{
5067 struct trace_array *tr = inode->i_private;
5068
5069 trace_array_put(tr);
5070
5071 return single_release(inode, file);
5072}
5073
5074static int tracing_open(struct inode *inode, struct file *file)
5075{
5076 struct trace_array *tr = inode->i_private;
5077 struct trace_iterator *iter;
5078 int ret;
5079
5080 ret = tracing_check_open_get_tr(tr);
5081 if (ret)
5082 return ret;
5083
5084 /* If this file was open for write, then erase contents */
5085 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
5086 int cpu = tracing_get_cpu(inode);
5087 struct array_buffer *trace_buf = &tr->array_buffer;
5088
5089#ifdef CONFIG_TRACER_MAX_TRACE
5090 if (tr->current_trace->print_max)
5091 trace_buf = &tr->max_buffer;
5092#endif
5093
5094 if (cpu == RING_BUFFER_ALL_CPUS)
5095 tracing_reset_online_cpus(trace_buf);
5096 else
5097 tracing_reset_cpu(trace_buf, cpu);
5098 }
5099
5100 if (file->f_mode & FMODE_READ) {
5101 iter = __tracing_open(inode, file, false);
5102 if (IS_ERR(iter))
5103 ret = PTR_ERR(iter);
5104 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
5105 iter->iter_flags |= TRACE_FILE_LAT_FMT;
5106 }
5107
5108 if (ret < 0)
5109 trace_array_put(tr);
5110
5111 return ret;
5112}
5113
5114/*
5115 * Some tracers are not suitable for instance buffers.
5116 * A tracer is always available for the global array (toplevel)
5117 * or if it explicitly states that it is.
5118 */
5119static bool
5120trace_ok_for_array(struct tracer *t, struct trace_array *tr)
5121{
5122 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
5123}
5124
5125/* Find the next tracer that this trace array may use */
5126static struct tracer *
5127get_tracer_for_array(struct trace_array *tr, struct tracer *t)
5128{
5129 while (t && !trace_ok_for_array(t, tr))
5130 t = t->next;
5131
5132 return t;
5133}
5134
5135static void *
5136t_next(struct seq_file *m, void *v, loff_t *pos)
5137{
5138 struct trace_array *tr = m->private;
5139 struct tracer *t = v;
5140
5141 (*pos)++;
5142
5143 if (t)
5144 t = get_tracer_for_array(tr, t->next);
5145
5146 return t;
5147}
5148
5149static void *t_start(struct seq_file *m, loff_t *pos)
5150{
5151 struct trace_array *tr = m->private;
5152 struct tracer *t;
5153 loff_t l = 0;
5154
5155 mutex_lock(&trace_types_lock);
5156
5157 t = get_tracer_for_array(tr, trace_types);
5158 for (; t && l < *pos; t = t_next(m, t, &l))
5159 ;
5160
5161 return t;
5162}
5163
5164static void t_stop(struct seq_file *m, void *p)
5165{
5166 mutex_unlock(&trace_types_lock);
5167}
5168
5169static int t_show(struct seq_file *m, void *v)
5170{
5171 struct tracer *t = v;
5172
5173 if (!t)
5174 return 0;
5175
5176 seq_puts(m, t->name);
5177 if (t->next)
5178 seq_putc(m, ' ');
5179 else
5180 seq_putc(m, '\n');
5181
5182 return 0;
5183}
5184
5185static const struct seq_operations show_traces_seq_ops = {
5186 .start = t_start,
5187 .next = t_next,
5188 .stop = t_stop,
5189 .show = t_show,
5190};
5191
5192static int show_traces_open(struct inode *inode, struct file *file)
5193{
5194 struct trace_array *tr = inode->i_private;
5195 struct seq_file *m;
5196 int ret;
5197
5198 ret = tracing_check_open_get_tr(tr);
5199 if (ret)
5200 return ret;
5201
5202 ret = seq_open(file, &show_traces_seq_ops);
5203 if (ret) {
5204 trace_array_put(tr);
5205 return ret;
5206 }
5207
5208 m = file->private_data;
5209 m->private = tr;
5210
5211 return 0;
5212}
5213
5214static int show_traces_release(struct inode *inode, struct file *file)
5215{
5216 struct trace_array *tr = inode->i_private;
5217
5218 trace_array_put(tr);
5219 return seq_release(inode, file);
5220}
5221
5222static ssize_t
5223tracing_write_stub(struct file *filp, const char __user *ubuf,
5224 size_t count, loff_t *ppos)
5225{
5226 return count;
5227}
5228
5229loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
5230{
5231 int ret;
5232
5233 if (file->f_mode & FMODE_READ)
5234 ret = seq_lseek(file, offset, whence);
5235 else
5236 file->f_pos = ret = 0;
5237
5238 return ret;
5239}
5240
5241static const struct file_operations tracing_fops = {
5242 .open = tracing_open,
5243 .read = seq_read,
5244 .read_iter = seq_read_iter,
5245 .splice_read = copy_splice_read,
5246 .write = tracing_write_stub,
5247 .llseek = tracing_lseek,
5248 .release = tracing_release,
5249};
5250
5251static const struct file_operations show_traces_fops = {
5252 .open = show_traces_open,
5253 .read = seq_read,
5254 .llseek = seq_lseek,
5255 .release = show_traces_release,
5256};
5257
5258static ssize_t
5259tracing_cpumask_read(struct file *filp, char __user *ubuf,
5260 size_t count, loff_t *ppos)
5261{
5262 struct trace_array *tr = file_inode(filp)->i_private;
5263 char *mask_str;
5264 int len;
5265
5266 len = snprintf(NULL, 0, "%*pb\n",
5267 cpumask_pr_args(tr->tracing_cpumask)) + 1;
5268 mask_str = kmalloc(len, GFP_KERNEL);
5269 if (!mask_str)
5270 return -ENOMEM;
5271
5272 len = snprintf(mask_str, len, "%*pb\n",
5273 cpumask_pr_args(tr->tracing_cpumask));
5274 if (len >= count) {
5275 count = -EINVAL;
5276 goto out_err;
5277 }
5278 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
5279
5280out_err:
5281 kfree(mask_str);
5282
5283 return count;
5284}
5285
5286int tracing_set_cpumask(struct trace_array *tr,
5287 cpumask_var_t tracing_cpumask_new)
5288{
5289 int cpu;
5290
5291 if (!tr)
5292 return -EINVAL;
5293
5294 local_irq_disable();
5295 arch_spin_lock(&tr->max_lock);
5296 for_each_tracing_cpu(cpu) {
5297 /*
5298 * Increase/decrease the disabled counter if we are
5299 * about to flip a bit in the cpumask:
5300 */
5301 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5302 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5303 atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5304 ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
5305#ifdef CONFIG_TRACER_MAX_TRACE
5306 ring_buffer_record_disable_cpu(tr->max_buffer.buffer, cpu);
5307#endif
5308 }
5309 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5310 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5311 atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5312 ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
5313#ifdef CONFIG_TRACER_MAX_TRACE
5314 ring_buffer_record_enable_cpu(tr->max_buffer.buffer, cpu);
5315#endif
5316 }
5317 }
5318 arch_spin_unlock(&tr->max_lock);
5319 local_irq_enable();
5320
5321 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
5322
5323 return 0;
5324}
5325
5326static ssize_t
5327tracing_cpumask_write(struct file *filp, const char __user *ubuf,
5328 size_t count, loff_t *ppos)
5329{
5330 struct trace_array *tr = file_inode(filp)->i_private;
5331 cpumask_var_t tracing_cpumask_new;
5332 int err;
5333
5334 if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
5335 return -ENOMEM;
5336
5337 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
5338 if (err)
5339 goto err_free;
5340
5341 err = tracing_set_cpumask(tr, tracing_cpumask_new);
5342 if (err)
5343 goto err_free;
5344
5345 free_cpumask_var(tracing_cpumask_new);
5346
5347 return count;
5348
5349err_free:
5350 free_cpumask_var(tracing_cpumask_new);
5351
5352 return err;
5353}
5354
5355static const struct file_operations tracing_cpumask_fops = {
5356 .open = tracing_open_generic_tr,
5357 .read = tracing_cpumask_read,
5358 .write = tracing_cpumask_write,
5359 .release = tracing_release_generic_tr,
5360 .llseek = generic_file_llseek,
5361};
5362
5363static int tracing_trace_options_show(struct seq_file *m, void *v)
5364{
5365 struct tracer_opt *trace_opts;
5366 struct trace_array *tr = m->private;
5367 u32 tracer_flags;
5368 int i;
5369
5370 mutex_lock(&trace_types_lock);
5371 tracer_flags = tr->current_trace->flags->val;
5372 trace_opts = tr->current_trace->flags->opts;
5373
5374 for (i = 0; trace_options[i]; i++) {
5375 if (tr->trace_flags & (1 << i))
5376 seq_printf(m, "%s\n", trace_options[i]);
5377 else
5378 seq_printf(m, "no%s\n", trace_options[i]);
5379 }
5380
5381 for (i = 0; trace_opts[i].name; i++) {
5382 if (tracer_flags & trace_opts[i].bit)
5383 seq_printf(m, "%s\n", trace_opts[i].name);
5384 else
5385 seq_printf(m, "no%s\n", trace_opts[i].name);
5386 }
5387 mutex_unlock(&trace_types_lock);
5388
5389 return 0;
5390}
5391
5392static int __set_tracer_option(struct trace_array *tr,
5393 struct tracer_flags *tracer_flags,
5394 struct tracer_opt *opts, int neg)
5395{
5396 struct tracer *trace = tracer_flags->trace;
5397 int ret;
5398
5399 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
5400 if (ret)
5401 return ret;
5402
5403 if (neg)
5404 tracer_flags->val &= ~opts->bit;
5405 else
5406 tracer_flags->val |= opts->bit;
5407 return 0;
5408}
5409
5410/* Try to assign a tracer specific option */
5411static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
5412{
5413 struct tracer *trace = tr->current_trace;
5414 struct tracer_flags *tracer_flags = trace->flags;
5415 struct tracer_opt *opts = NULL;
5416 int i;
5417
5418 for (i = 0; tracer_flags->opts[i].name; i++) {
5419 opts = &tracer_flags->opts[i];
5420
5421 if (strcmp(cmp, opts->name) == 0)
5422 return __set_tracer_option(tr, trace->flags, opts, neg);
5423 }
5424
5425 return -EINVAL;
5426}
5427
5428/* Some tracers require overwrite to stay enabled */
5429int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
5430{
5431 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
5432 return -1;
5433
5434 return 0;
5435}
5436
5437int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
5438{
5439 int *map;
5440
5441 if ((mask == TRACE_ITER_RECORD_TGID) ||
5442 (mask == TRACE_ITER_RECORD_CMD))
5443 lockdep_assert_held(&event_mutex);
5444
5445 /* do nothing if flag is already set */
5446 if (!!(tr->trace_flags & mask) == !!enabled)
5447 return 0;
5448
5449 /* Give the tracer a chance to approve the change */
5450 if (tr->current_trace->flag_changed)
5451 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
5452 return -EINVAL;
5453
5454 if (enabled)
5455 tr->trace_flags |= mask;
5456 else
5457 tr->trace_flags &= ~mask;
5458
5459 if (mask == TRACE_ITER_RECORD_CMD)
5460 trace_event_enable_cmd_record(enabled);
5461
5462 if (mask == TRACE_ITER_RECORD_TGID) {
5463 if (!tgid_map) {
5464 tgid_map_max = pid_max;
5465 map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map),
5466 GFP_KERNEL);
5467
5468 /*
5469 * Pairs with smp_load_acquire() in
5470 * trace_find_tgid_ptr() to ensure that if it observes
5471 * the tgid_map we just allocated then it also observes
5472 * the corresponding tgid_map_max value.
5473 */
5474 smp_store_release(&tgid_map, map);
5475 }
5476 if (!tgid_map) {
5477 tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
5478 return -ENOMEM;
5479 }
5480
5481 trace_event_enable_tgid_record(enabled);
5482 }
5483
5484 if (mask == TRACE_ITER_EVENT_FORK)
5485 trace_event_follow_fork(tr, enabled);
5486
5487 if (mask == TRACE_ITER_FUNC_FORK)
5488 ftrace_pid_follow_fork(tr, enabled);
5489
5490 if (mask == TRACE_ITER_OVERWRITE) {
5491 ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled);
5492#ifdef CONFIG_TRACER_MAX_TRACE
5493 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
5494#endif
5495 }
5496
5497 if (mask == TRACE_ITER_PRINTK) {
5498 trace_printk_start_stop_comm(enabled);
5499 trace_printk_control(enabled);
5500 }
5501
5502 return 0;
5503}
5504
5505int trace_set_options(struct trace_array *tr, char *option)
5506{
5507 char *cmp;
5508 int neg = 0;
5509 int ret;
5510 size_t orig_len = strlen(option);
5511 int len;
5512
5513 cmp = strstrip(option);
5514
5515 len = str_has_prefix(cmp, "no");
5516 if (len)
5517 neg = 1;
5518
5519 cmp += len;
5520
5521 mutex_lock(&event_mutex);
5522 mutex_lock(&trace_types_lock);
5523
5524 ret = match_string(trace_options, -1, cmp);
5525 /* If no option could be set, test the specific tracer options */
5526 if (ret < 0)
5527 ret = set_tracer_option(tr, cmp, neg);
5528 else
5529 ret = set_tracer_flag(tr, 1 << ret, !neg);
5530
5531 mutex_unlock(&trace_types_lock);
5532 mutex_unlock(&event_mutex);
5533
5534 /*
5535 * If the first trailing whitespace is replaced with '\0' by strstrip,
5536 * turn it back into a space.
5537 */
5538 if (orig_len > strlen(option))
5539 option[strlen(option)] = ' ';
5540
5541 return ret;
5542}
5543
5544static void __init apply_trace_boot_options(void)
5545{
5546 char *buf = trace_boot_options_buf;
5547 char *option;
5548
5549 while (true) {
5550 option = strsep(&buf, ",");
5551
5552 if (!option)
5553 break;
5554
5555 if (*option)
5556 trace_set_options(&global_trace, option);
5557
5558 /* Put back the comma to allow this to be called again */
5559 if (buf)
5560 *(buf - 1) = ',';
5561 }
5562}
5563
5564static ssize_t
5565tracing_trace_options_write(struct file *filp, const char __user *ubuf,
5566 size_t cnt, loff_t *ppos)
5567{
5568 struct seq_file *m = filp->private_data;
5569 struct trace_array *tr = m->private;
5570 char buf[64];
5571 int ret;
5572
5573 if (cnt >= sizeof(buf))
5574 return -EINVAL;
5575
5576 if (copy_from_user(buf, ubuf, cnt))
5577 return -EFAULT;
5578
5579 buf[cnt] = 0;
5580
5581 ret = trace_set_options(tr, buf);
5582 if (ret < 0)
5583 return ret;
5584
5585 *ppos += cnt;
5586
5587 return cnt;
5588}
5589
5590static int tracing_trace_options_open(struct inode *inode, struct file *file)
5591{
5592 struct trace_array *tr = inode->i_private;
5593 int ret;
5594
5595 ret = tracing_check_open_get_tr(tr);
5596 if (ret)
5597 return ret;
5598
5599 ret = single_open(file, tracing_trace_options_show, inode->i_private);
5600 if (ret < 0)
5601 trace_array_put(tr);
5602
5603 return ret;
5604}
5605
5606static const struct file_operations tracing_iter_fops = {
5607 .open = tracing_trace_options_open,
5608 .read = seq_read,
5609 .llseek = seq_lseek,
5610 .release = tracing_single_release_tr,
5611 .write = tracing_trace_options_write,
5612};
5613
5614static const char readme_msg[] =
5615 "tracing mini-HOWTO:\n\n"
5616 "# echo 0 > tracing_on : quick way to disable tracing\n"
5617 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
5618 " Important files:\n"
5619 " trace\t\t\t- The static contents of the buffer\n"
5620 "\t\t\t To clear the buffer write into this file: echo > trace\n"
5621 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
5622 " current_tracer\t- function and latency tracers\n"
5623 " available_tracers\t- list of configured tracers for current_tracer\n"
5624 " error_log\t- error log for failed commands (that support it)\n"
5625 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
5626 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
5627 " trace_clock\t\t- change the clock used to order events\n"
5628 " local: Per cpu clock but may not be synced across CPUs\n"
5629 " global: Synced across CPUs but slows tracing down.\n"
5630 " counter: Not a clock, but just an increment\n"
5631 " uptime: Jiffy counter from time of boot\n"
5632 " perf: Same clock that perf events use\n"
5633#ifdef CONFIG_X86_64
5634 " x86-tsc: TSC cycle counter\n"
5635#endif
5636 "\n timestamp_mode\t- view the mode used to timestamp events\n"
5637 " delta: Delta difference against a buffer-wide timestamp\n"
5638 " absolute: Absolute (standalone) timestamp\n"
5639 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
5640 "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
5641 " tracing_cpumask\t- Limit which CPUs to trace\n"
5642 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
5643 "\t\t\t Remove sub-buffer with rmdir\n"
5644 " trace_options\t\t- Set format or modify how tracing happens\n"
5645 "\t\t\t Disable an option by prefixing 'no' to the\n"
5646 "\t\t\t option name\n"
5647 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
5648#ifdef CONFIG_DYNAMIC_FTRACE
5649 "\n available_filter_functions - list of functions that can be filtered on\n"
5650 " set_ftrace_filter\t- echo function name in here to only trace these\n"
5651 "\t\t\t functions\n"
5652 "\t accepts: func_full_name or glob-matching-pattern\n"
5653 "\t modules: Can select a group via module\n"
5654 "\t Format: :mod:<module-name>\n"
5655 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
5656 "\t triggers: a command to perform when function is hit\n"
5657 "\t Format: <function>:<trigger>[:count]\n"
5658 "\t trigger: traceon, traceoff\n"
5659 "\t\t enable_event:<system>:<event>\n"
5660 "\t\t disable_event:<system>:<event>\n"
5661#ifdef CONFIG_STACKTRACE
5662 "\t\t stacktrace\n"
5663#endif
5664#ifdef CONFIG_TRACER_SNAPSHOT
5665 "\t\t snapshot\n"
5666#endif
5667 "\t\t dump\n"
5668 "\t\t cpudump\n"
5669 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
5670 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
5671 "\t The first one will disable tracing every time do_fault is hit\n"
5672 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
5673 "\t The first time do trap is hit and it disables tracing, the\n"
5674 "\t counter will decrement to 2. If tracing is already disabled,\n"
5675 "\t the counter will not decrement. It only decrements when the\n"
5676 "\t trigger did work\n"
5677 "\t To remove trigger without count:\n"
5678 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
5679 "\t To remove trigger with a count:\n"
5680 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
5681 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
5682 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
5683 "\t modules: Can select a group via module command :mod:\n"
5684 "\t Does not accept triggers\n"
5685#endif /* CONFIG_DYNAMIC_FTRACE */
5686#ifdef CONFIG_FUNCTION_TRACER
5687 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
5688 "\t\t (function)\n"
5689 " set_ftrace_notrace_pid\t- Write pid(s) to not function trace those pids\n"
5690 "\t\t (function)\n"
5691#endif
5692#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5693 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
5694 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
5695 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
5696#endif
5697#ifdef CONFIG_TRACER_SNAPSHOT
5698 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
5699 "\t\t\t snapshot buffer. Read the contents for more\n"
5700 "\t\t\t information\n"
5701#endif
5702#ifdef CONFIG_STACK_TRACER
5703 " stack_trace\t\t- Shows the max stack trace when active\n"
5704 " stack_max_size\t- Shows current max stack size that was traced\n"
5705 "\t\t\t Write into this file to reset the max size (trigger a\n"
5706 "\t\t\t new trace)\n"
5707#ifdef CONFIG_DYNAMIC_FTRACE
5708 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
5709 "\t\t\t traces\n"
5710#endif
5711#endif /* CONFIG_STACK_TRACER */
5712#ifdef CONFIG_DYNAMIC_EVENTS
5713 " dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
5714 "\t\t\t Write into this file to define/undefine new trace events.\n"
5715#endif
5716#ifdef CONFIG_KPROBE_EVENTS
5717 " kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
5718 "\t\t\t Write into this file to define/undefine new trace events.\n"
5719#endif
5720#ifdef CONFIG_UPROBE_EVENTS
5721 " uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
5722 "\t\t\t Write into this file to define/undefine new trace events.\n"
5723#endif
5724#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) || \
5725 defined(CONFIG_FPROBE_EVENTS)
5726 "\t accepts: event-definitions (one definition per line)\n"
5727#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
5728 "\t Format: p[:[<group>/][<event>]] <place> [<args>]\n"
5729 "\t r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
5730#endif
5731#ifdef CONFIG_FPROBE_EVENTS
5732 "\t f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n"
5733 "\t t[:[<group>/][<event>]] <tracepoint> [<args>]\n"
5734#endif
5735#ifdef CONFIG_HIST_TRIGGERS
5736 "\t s:[synthetic/]<event> <field> [<field>]\n"
5737#endif
5738 "\t e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>] [if <filter>]\n"
5739 "\t -:[<group>/][<event>]\n"
5740#ifdef CONFIG_KPROBE_EVENTS
5741 "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
5742 "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n"
5743#endif
5744#ifdef CONFIG_UPROBE_EVENTS
5745 " place (uprobe): <path>:<offset>[%return][(ref_ctr_offset)]\n"
5746#endif
5747 "\t args: <name>=fetcharg[:type]\n"
5748 "\t fetcharg: (%<register>|$<efield>), @<address>, @<symbol>[+|-<offset>],\n"
5749#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
5750#ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
5751 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
5752 "\t <argname>[->field[->field|.field...]],\n"
5753#else
5754 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
5755#endif
5756#else
5757 "\t $stack<index>, $stack, $retval, $comm,\n"
5758#endif
5759 "\t +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
5760 "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, char, string, symbol,\n"
5761 "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
5762 "\t symstr, <type>\\[<array-size>\\]\n"
5763#ifdef CONFIG_HIST_TRIGGERS
5764 "\t field: <stype> <name>;\n"
5765 "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
5766 "\t [unsigned] char/int/long\n"
5767#endif
5768 "\t efield: For event probes ('e' types), the field is on of the fields\n"
5769 "\t of the <attached-group>/<attached-event>.\n"
5770#endif
5771 " events/\t\t- Directory containing all trace event subsystems:\n"
5772 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
5773 " events/<system>/\t- Directory containing all trace events for <system>:\n"
5774 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
5775 "\t\t\t events\n"
5776 " filter\t\t- If set, only events passing filter are traced\n"
5777 " events/<system>/<event>/\t- Directory containing control files for\n"
5778 "\t\t\t <event>:\n"
5779 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
5780 " filter\t\t- If set, only events passing filter are traced\n"
5781 " trigger\t\t- If set, a command to perform when event is hit\n"
5782 "\t Format: <trigger>[:count][if <filter>]\n"
5783 "\t trigger: traceon, traceoff\n"
5784 "\t enable_event:<system>:<event>\n"
5785 "\t disable_event:<system>:<event>\n"
5786#ifdef CONFIG_HIST_TRIGGERS
5787 "\t enable_hist:<system>:<event>\n"
5788 "\t disable_hist:<system>:<event>\n"
5789#endif
5790#ifdef CONFIG_STACKTRACE
5791 "\t\t stacktrace\n"
5792#endif
5793#ifdef CONFIG_TRACER_SNAPSHOT
5794 "\t\t snapshot\n"
5795#endif
5796#ifdef CONFIG_HIST_TRIGGERS
5797 "\t\t hist (see below)\n"
5798#endif
5799 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
5800 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
5801 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
5802 "\t events/block/block_unplug/trigger\n"
5803 "\t The first disables tracing every time block_unplug is hit.\n"
5804 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
5805 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
5806 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
5807 "\t Like function triggers, the counter is only decremented if it\n"
5808 "\t enabled or disabled tracing.\n"
5809 "\t To remove a trigger without a count:\n"
5810 "\t echo '!<trigger> > <system>/<event>/trigger\n"
5811 "\t To remove a trigger with a count:\n"
5812 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
5813 "\t Filters can be ignored when removing a trigger.\n"
5814#ifdef CONFIG_HIST_TRIGGERS
5815 " hist trigger\t- If set, event hits are aggregated into a hash table\n"
5816 "\t Format: hist:keys=<field1[,field2,...]>\n"
5817 "\t [:<var1>=<field|var_ref|numeric_literal>[,<var2>=...]]\n"
5818 "\t [:values=<field1[,field2,...]>]\n"
5819 "\t [:sort=<field1[,field2,...]>]\n"
5820 "\t [:size=#entries]\n"
5821 "\t [:pause][:continue][:clear]\n"
5822 "\t [:name=histname1]\n"
5823 "\t [:nohitcount]\n"
5824 "\t [:<handler>.<action>]\n"
5825 "\t [if <filter>]\n\n"
5826 "\t Note, special fields can be used as well:\n"
5827 "\t common_timestamp - to record current timestamp\n"
5828 "\t common_cpu - to record the CPU the event happened on\n"
5829 "\n"
5830 "\t A hist trigger variable can be:\n"
5831 "\t - a reference to a field e.g. x=current_timestamp,\n"
5832 "\t - a reference to another variable e.g. y=$x,\n"
5833 "\t - a numeric literal: e.g. ms_per_sec=1000,\n"
5834 "\t - an arithmetic expression: e.g. time_secs=current_timestamp/1000\n"
5835 "\n"
5836 "\t hist trigger arithmetic expressions support addition(+), subtraction(-),\n"
5837 "\t multiplication(*) and division(/) operators. An operand can be either a\n"
5838 "\t variable reference, field or numeric literal.\n"
5839 "\n"
5840 "\t When a matching event is hit, an entry is added to a hash\n"
5841 "\t table using the key(s) and value(s) named, and the value of a\n"
5842 "\t sum called 'hitcount' is incremented. Keys and values\n"
5843 "\t correspond to fields in the event's format description. Keys\n"
5844 "\t can be any field, or the special string 'common_stacktrace'.\n"
5845 "\t Compound keys consisting of up to two fields can be specified\n"
5846 "\t by the 'keys' keyword. Values must correspond to numeric\n"
5847 "\t fields. Sort keys consisting of up to two fields can be\n"
5848 "\t specified using the 'sort' keyword. The sort direction can\n"
5849 "\t be modified by appending '.descending' or '.ascending' to a\n"
5850 "\t sort field. The 'size' parameter can be used to specify more\n"
5851 "\t or fewer than the default 2048 entries for the hashtable size.\n"
5852 "\t If a hist trigger is given a name using the 'name' parameter,\n"
5853 "\t its histogram data will be shared with other triggers of the\n"
5854 "\t same name, and trigger hits will update this common data.\n\n"
5855 "\t Reading the 'hist' file for the event will dump the hash\n"
5856 "\t table in its entirety to stdout. If there are multiple hist\n"
5857 "\t triggers attached to an event, there will be a table for each\n"
5858 "\t trigger in the output. The table displayed for a named\n"
5859 "\t trigger will be the same as any other instance having the\n"
5860 "\t same name. The default format used to display a given field\n"
5861 "\t can be modified by appending any of the following modifiers\n"
5862 "\t to the field name, as applicable:\n\n"
5863 "\t .hex display a number as a hex value\n"
5864 "\t .sym display an address as a symbol\n"
5865 "\t .sym-offset display an address as a symbol and offset\n"
5866 "\t .execname display a common_pid as a program name\n"
5867 "\t .syscall display a syscall id as a syscall name\n"
5868 "\t .log2 display log2 value rather than raw number\n"
5869 "\t .buckets=size display values in groups of size rather than raw number\n"
5870 "\t .usecs display a common_timestamp in microseconds\n"
5871 "\t .percent display a number of percentage value\n"
5872 "\t .graph display a bar-graph of a value\n\n"
5873 "\t The 'pause' parameter can be used to pause an existing hist\n"
5874 "\t trigger or to start a hist trigger but not log any events\n"
5875 "\t until told to do so. 'continue' can be used to start or\n"
5876 "\t restart a paused hist trigger.\n\n"
5877 "\t The 'clear' parameter will clear the contents of a running\n"
5878 "\t hist trigger and leave its current paused/active state\n"
5879 "\t unchanged.\n\n"
5880 "\t The 'nohitcount' (or NOHC) parameter will suppress display of\n"
5881 "\t raw hitcount in the histogram.\n\n"
5882 "\t The enable_hist and disable_hist triggers can be used to\n"
5883 "\t have one event conditionally start and stop another event's\n"
5884 "\t already-attached hist trigger. The syntax is analogous to\n"
5885 "\t the enable_event and disable_event triggers.\n\n"
5886 "\t Hist trigger handlers and actions are executed whenever a\n"
5887 "\t a histogram entry is added or updated. They take the form:\n\n"
5888 "\t <handler>.<action>\n\n"
5889 "\t The available handlers are:\n\n"
5890 "\t onmatch(matching.event) - invoke on addition or update\n"
5891 "\t onmax(var) - invoke if var exceeds current max\n"
5892 "\t onchange(var) - invoke action if var changes\n\n"
5893 "\t The available actions are:\n\n"
5894 "\t trace(<synthetic_event>,param list) - generate synthetic event\n"
5895 "\t save(field,...) - save current event fields\n"
5896#ifdef CONFIG_TRACER_SNAPSHOT
5897 "\t snapshot() - snapshot the trace buffer\n\n"
5898#endif
5899#ifdef CONFIG_SYNTH_EVENTS
5900 " events/synthetic_events\t- Create/append/remove/show synthetic events\n"
5901 "\t Write into this file to define/undefine new synthetic events.\n"
5902 "\t example: echo 'myevent u64 lat; char name[]; long[] stack' >> synthetic_events\n"
5903#endif
5904#endif
5905;
5906
5907static ssize_t
5908tracing_readme_read(struct file *filp, char __user *ubuf,
5909 size_t cnt, loff_t *ppos)
5910{
5911 return simple_read_from_buffer(ubuf, cnt, ppos,
5912 readme_msg, strlen(readme_msg));
5913}
5914
5915static const struct file_operations tracing_readme_fops = {
5916 .open = tracing_open_generic,
5917 .read = tracing_readme_read,
5918 .llseek = generic_file_llseek,
5919};
5920
5921static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
5922{
5923 int pid = ++(*pos);
5924
5925 return trace_find_tgid_ptr(pid);
5926}
5927
5928static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
5929{
5930 int pid = *pos;
5931
5932 return trace_find_tgid_ptr(pid);
5933}
5934
5935static void saved_tgids_stop(struct seq_file *m, void *v)
5936{
5937}
5938
5939static int saved_tgids_show(struct seq_file *m, void *v)
5940{
5941 int *entry = (int *)v;
5942 int pid = entry - tgid_map;
5943 int tgid = *entry;
5944
5945 if (tgid == 0)
5946 return SEQ_SKIP;
5947
5948 seq_printf(m, "%d %d\n", pid, tgid);
5949 return 0;
5950}
5951
5952static const struct seq_operations tracing_saved_tgids_seq_ops = {
5953 .start = saved_tgids_start,
5954 .stop = saved_tgids_stop,
5955 .next = saved_tgids_next,
5956 .show = saved_tgids_show,
5957};
5958
5959static int tracing_saved_tgids_open(struct inode *inode, struct file *filp)
5960{
5961 int ret;
5962
5963 ret = tracing_check_open_get_tr(NULL);
5964 if (ret)
5965 return ret;
5966
5967 return seq_open(filp, &tracing_saved_tgids_seq_ops);
5968}
5969
5970
5971static const struct file_operations tracing_saved_tgids_fops = {
5972 .open = tracing_saved_tgids_open,
5973 .read = seq_read,
5974 .llseek = seq_lseek,
5975 .release = seq_release,
5976};
5977
5978static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
5979{
5980 unsigned int *ptr = v;
5981
5982 if (*pos || m->count)
5983 ptr++;
5984
5985 (*pos)++;
5986
5987 for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
5988 ptr++) {
5989 if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
5990 continue;
5991
5992 return ptr;
5993 }
5994
5995 return NULL;
5996}
5997
5998static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
5999{
6000 void *v;
6001 loff_t l = 0;
6002
6003 preempt_disable();
6004 arch_spin_lock(&trace_cmdline_lock);
6005
6006 v = &savedcmd->map_cmdline_to_pid[0];
6007 while (l <= *pos) {
6008 v = saved_cmdlines_next(m, v, &l);
6009 if (!v)
6010 return NULL;
6011 }
6012
6013 return v;
6014}
6015
6016static void saved_cmdlines_stop(struct seq_file *m, void *v)
6017{
6018 arch_spin_unlock(&trace_cmdline_lock);
6019 preempt_enable();
6020}
6021
6022static int saved_cmdlines_show(struct seq_file *m, void *v)
6023{
6024 char buf[TASK_COMM_LEN];
6025 unsigned int *pid = v;
6026
6027 __trace_find_cmdline(*pid, buf);
6028 seq_printf(m, "%d %s\n", *pid, buf);
6029 return 0;
6030}
6031
6032static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
6033 .start = saved_cmdlines_start,
6034 .next = saved_cmdlines_next,
6035 .stop = saved_cmdlines_stop,
6036 .show = saved_cmdlines_show,
6037};
6038
6039static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
6040{
6041 int ret;
6042
6043 ret = tracing_check_open_get_tr(NULL);
6044 if (ret)
6045 return ret;
6046
6047 return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
6048}
6049
6050static const struct file_operations tracing_saved_cmdlines_fops = {
6051 .open = tracing_saved_cmdlines_open,
6052 .read = seq_read,
6053 .llseek = seq_lseek,
6054 .release = seq_release,
6055};
6056
6057static ssize_t
6058tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
6059 size_t cnt, loff_t *ppos)
6060{
6061 char buf[64];
6062 int r;
6063
6064 preempt_disable();
6065 arch_spin_lock(&trace_cmdline_lock);
6066 r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
6067 arch_spin_unlock(&trace_cmdline_lock);
6068 preempt_enable();
6069
6070 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6071}
6072
6073static int tracing_resize_saved_cmdlines(unsigned int val)
6074{
6075 struct saved_cmdlines_buffer *s, *savedcmd_temp;
6076
6077 s = allocate_cmdlines_buffer(val);
6078 if (!s)
6079 return -ENOMEM;
6080
6081 preempt_disable();
6082 arch_spin_lock(&trace_cmdline_lock);
6083 savedcmd_temp = savedcmd;
6084 savedcmd = s;
6085 arch_spin_unlock(&trace_cmdline_lock);
6086 preempt_enable();
6087 free_saved_cmdlines_buffer(savedcmd_temp);
6088
6089 return 0;
6090}
6091
6092static ssize_t
6093tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
6094 size_t cnt, loff_t *ppos)
6095{
6096 unsigned long val;
6097 int ret;
6098
6099 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6100 if (ret)
6101 return ret;
6102
6103 /* must have at least 1 entry or less than PID_MAX_DEFAULT */
6104 if (!val || val > PID_MAX_DEFAULT)
6105 return -EINVAL;
6106
6107 ret = tracing_resize_saved_cmdlines((unsigned int)val);
6108 if (ret < 0)
6109 return ret;
6110
6111 *ppos += cnt;
6112
6113 return cnt;
6114}
6115
6116static const struct file_operations tracing_saved_cmdlines_size_fops = {
6117 .open = tracing_open_generic,
6118 .read = tracing_saved_cmdlines_size_read,
6119 .write = tracing_saved_cmdlines_size_write,
6120};
6121
6122#ifdef CONFIG_TRACE_EVAL_MAP_FILE
6123static union trace_eval_map_item *
6124update_eval_map(union trace_eval_map_item *ptr)
6125{
6126 if (!ptr->map.eval_string) {
6127 if (ptr->tail.next) {
6128 ptr = ptr->tail.next;
6129 /* Set ptr to the next real item (skip head) */
6130 ptr++;
6131 } else
6132 return NULL;
6133 }
6134 return ptr;
6135}
6136
6137static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
6138{
6139 union trace_eval_map_item *ptr = v;
6140
6141 /*
6142 * Paranoid! If ptr points to end, we don't want to increment past it.
6143 * This really should never happen.
6144 */
6145 (*pos)++;
6146 ptr = update_eval_map(ptr);
6147 if (WARN_ON_ONCE(!ptr))
6148 return NULL;
6149
6150 ptr++;
6151 ptr = update_eval_map(ptr);
6152
6153 return ptr;
6154}
6155
6156static void *eval_map_start(struct seq_file *m, loff_t *pos)
6157{
6158 union trace_eval_map_item *v;
6159 loff_t l = 0;
6160
6161 mutex_lock(&trace_eval_mutex);
6162
6163 v = trace_eval_maps;
6164 if (v)
6165 v++;
6166
6167 while (v && l < *pos) {
6168 v = eval_map_next(m, v, &l);
6169 }
6170
6171 return v;
6172}
6173
6174static void eval_map_stop(struct seq_file *m, void *v)
6175{
6176 mutex_unlock(&trace_eval_mutex);
6177}
6178
6179static int eval_map_show(struct seq_file *m, void *v)
6180{
6181 union trace_eval_map_item *ptr = v;
6182
6183 seq_printf(m, "%s %ld (%s)\n",
6184 ptr->map.eval_string, ptr->map.eval_value,
6185 ptr->map.system);
6186
6187 return 0;
6188}
6189
6190static const struct seq_operations tracing_eval_map_seq_ops = {
6191 .start = eval_map_start,
6192 .next = eval_map_next,
6193 .stop = eval_map_stop,
6194 .show = eval_map_show,
6195};
6196
6197static int tracing_eval_map_open(struct inode *inode, struct file *filp)
6198{
6199 int ret;
6200
6201 ret = tracing_check_open_get_tr(NULL);
6202 if (ret)
6203 return ret;
6204
6205 return seq_open(filp, &tracing_eval_map_seq_ops);
6206}
6207
6208static const struct file_operations tracing_eval_map_fops = {
6209 .open = tracing_eval_map_open,
6210 .read = seq_read,
6211 .llseek = seq_lseek,
6212 .release = seq_release,
6213};
6214
6215static inline union trace_eval_map_item *
6216trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
6217{
6218 /* Return tail of array given the head */
6219 return ptr + ptr->head.length + 1;
6220}
6221
6222static void
6223trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
6224 int len)
6225{
6226 struct trace_eval_map **stop;
6227 struct trace_eval_map **map;
6228 union trace_eval_map_item *map_array;
6229 union trace_eval_map_item *ptr;
6230
6231 stop = start + len;
6232
6233 /*
6234 * The trace_eval_maps contains the map plus a head and tail item,
6235 * where the head holds the module and length of array, and the
6236 * tail holds a pointer to the next list.
6237 */
6238 map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
6239 if (!map_array) {
6240 pr_warn("Unable to allocate trace eval mapping\n");
6241 return;
6242 }
6243
6244 mutex_lock(&trace_eval_mutex);
6245
6246 if (!trace_eval_maps)
6247 trace_eval_maps = map_array;
6248 else {
6249 ptr = trace_eval_maps;
6250 for (;;) {
6251 ptr = trace_eval_jmp_to_tail(ptr);
6252 if (!ptr->tail.next)
6253 break;
6254 ptr = ptr->tail.next;
6255
6256 }
6257 ptr->tail.next = map_array;
6258 }
6259 map_array->head.mod = mod;
6260 map_array->head.length = len;
6261 map_array++;
6262
6263 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
6264 map_array->map = **map;
6265 map_array++;
6266 }
6267 memset(map_array, 0, sizeof(*map_array));
6268
6269 mutex_unlock(&trace_eval_mutex);
6270}
6271
6272static void trace_create_eval_file(struct dentry *d_tracer)
6273{
6274 trace_create_file("eval_map", TRACE_MODE_READ, d_tracer,
6275 NULL, &tracing_eval_map_fops);
6276}
6277
6278#else /* CONFIG_TRACE_EVAL_MAP_FILE */
6279static inline void trace_create_eval_file(struct dentry *d_tracer) { }
6280static inline void trace_insert_eval_map_file(struct module *mod,
6281 struct trace_eval_map **start, int len) { }
6282#endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
6283
6284static void trace_insert_eval_map(struct module *mod,
6285 struct trace_eval_map **start, int len)
6286{
6287 struct trace_eval_map **map;
6288
6289 if (len <= 0)
6290 return;
6291
6292 map = start;
6293
6294 trace_event_eval_update(map, len);
6295
6296 trace_insert_eval_map_file(mod, start, len);
6297}
6298
6299static ssize_t
6300tracing_set_trace_read(struct file *filp, char __user *ubuf,
6301 size_t cnt, loff_t *ppos)
6302{
6303 struct trace_array *tr = filp->private_data;
6304 char buf[MAX_TRACER_SIZE+2];
6305 int r;
6306
6307 mutex_lock(&trace_types_lock);
6308 r = sprintf(buf, "%s\n", tr->current_trace->name);
6309 mutex_unlock(&trace_types_lock);
6310
6311 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6312}
6313
6314int tracer_init(struct tracer *t, struct trace_array *tr)
6315{
6316 tracing_reset_online_cpus(&tr->array_buffer);
6317 return t->init(tr);
6318}
6319
6320static void set_buffer_entries(struct array_buffer *buf, unsigned long val)
6321{
6322 int cpu;
6323
6324 for_each_tracing_cpu(cpu)
6325 per_cpu_ptr(buf->data, cpu)->entries = val;
6326}
6327
6328static void update_buffer_entries(struct array_buffer *buf, int cpu)
6329{
6330 if (cpu == RING_BUFFER_ALL_CPUS) {
6331 set_buffer_entries(buf, ring_buffer_size(buf->buffer, 0));
6332 } else {
6333 per_cpu_ptr(buf->data, cpu)->entries = ring_buffer_size(buf->buffer, cpu);
6334 }
6335}
6336
6337#ifdef CONFIG_TRACER_MAX_TRACE
6338/* resize @tr's buffer to the size of @size_tr's entries */
6339static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
6340 struct array_buffer *size_buf, int cpu_id)
6341{
6342 int cpu, ret = 0;
6343
6344 if (cpu_id == RING_BUFFER_ALL_CPUS) {
6345 for_each_tracing_cpu(cpu) {
6346 ret = ring_buffer_resize(trace_buf->buffer,
6347 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
6348 if (ret < 0)
6349 break;
6350 per_cpu_ptr(trace_buf->data, cpu)->entries =
6351 per_cpu_ptr(size_buf->data, cpu)->entries;
6352 }
6353 } else {
6354 ret = ring_buffer_resize(trace_buf->buffer,
6355 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
6356 if (ret == 0)
6357 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
6358 per_cpu_ptr(size_buf->data, cpu_id)->entries;
6359 }
6360
6361 return ret;
6362}
6363#endif /* CONFIG_TRACER_MAX_TRACE */
6364
6365static int __tracing_resize_ring_buffer(struct trace_array *tr,
6366 unsigned long size, int cpu)
6367{
6368 int ret;
6369
6370 /*
6371 * If kernel or user changes the size of the ring buffer
6372 * we use the size that was given, and we can forget about
6373 * expanding it later.
6374 */
6375 trace_set_ring_buffer_expanded(tr);
6376
6377 /* May be called before buffers are initialized */
6378 if (!tr->array_buffer.buffer)
6379 return 0;
6380
6381 /* Do not allow tracing while resizing ring buffer */
6382 tracing_stop_tr(tr);
6383
6384 ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu);
6385 if (ret < 0)
6386 goto out_start;
6387
6388#ifdef CONFIG_TRACER_MAX_TRACE
6389 if (!tr->allocated_snapshot)
6390 goto out;
6391
6392 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
6393 if (ret < 0) {
6394 int r = resize_buffer_duplicate_size(&tr->array_buffer,
6395 &tr->array_buffer, cpu);
6396 if (r < 0) {
6397 /*
6398 * AARGH! We are left with different
6399 * size max buffer!!!!
6400 * The max buffer is our "snapshot" buffer.
6401 * When a tracer needs a snapshot (one of the
6402 * latency tracers), it swaps the max buffer
6403 * with the saved snap shot. We succeeded to
6404 * update the size of the main buffer, but failed to
6405 * update the size of the max buffer. But when we tried
6406 * to reset the main buffer to the original size, we
6407 * failed there too. This is very unlikely to
6408 * happen, but if it does, warn and kill all
6409 * tracing.
6410 */
6411 WARN_ON(1);
6412 tracing_disabled = 1;
6413 }
6414 goto out_start;
6415 }
6416
6417 update_buffer_entries(&tr->max_buffer, cpu);
6418
6419 out:
6420#endif /* CONFIG_TRACER_MAX_TRACE */
6421
6422 update_buffer_entries(&tr->array_buffer, cpu);
6423 out_start:
6424 tracing_start_tr(tr);
6425 return ret;
6426}
6427
6428ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
6429 unsigned long size, int cpu_id)
6430{
6431 int ret;
6432
6433 mutex_lock(&trace_types_lock);
6434
6435 if (cpu_id != RING_BUFFER_ALL_CPUS) {
6436 /* make sure, this cpu is enabled in the mask */
6437 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
6438 ret = -EINVAL;
6439 goto out;
6440 }
6441 }
6442
6443 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
6444 if (ret < 0)
6445 ret = -ENOMEM;
6446
6447out:
6448 mutex_unlock(&trace_types_lock);
6449
6450 return ret;
6451}
6452
6453
6454/**
6455 * tracing_update_buffers - used by tracing facility to expand ring buffers
6456 * @tr: The tracing instance
6457 *
6458 * To save on memory when the tracing is never used on a system with it
6459 * configured in. The ring buffers are set to a minimum size. But once
6460 * a user starts to use the tracing facility, then they need to grow
6461 * to their default size.
6462 *
6463 * This function is to be called when a tracer is about to be used.
6464 */
6465int tracing_update_buffers(struct trace_array *tr)
6466{
6467 int ret = 0;
6468
6469 mutex_lock(&trace_types_lock);
6470 if (!tr->ring_buffer_expanded)
6471 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6472 RING_BUFFER_ALL_CPUS);
6473 mutex_unlock(&trace_types_lock);
6474
6475 return ret;
6476}
6477
6478struct trace_option_dentry;
6479
6480static void
6481create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
6482
6483/*
6484 * Used to clear out the tracer before deletion of an instance.
6485 * Must have trace_types_lock held.
6486 */
6487static void tracing_set_nop(struct trace_array *tr)
6488{
6489 if (tr->current_trace == &nop_trace)
6490 return;
6491
6492 tr->current_trace->enabled--;
6493
6494 if (tr->current_trace->reset)
6495 tr->current_trace->reset(tr);
6496
6497 tr->current_trace = &nop_trace;
6498}
6499
6500static bool tracer_options_updated;
6501
6502static void add_tracer_options(struct trace_array *tr, struct tracer *t)
6503{
6504 /* Only enable if the directory has been created already. */
6505 if (!tr->dir)
6506 return;
6507
6508 /* Only create trace option files after update_tracer_options finish */
6509 if (!tracer_options_updated)
6510 return;
6511
6512 create_trace_option_files(tr, t);
6513}
6514
6515int tracing_set_tracer(struct trace_array *tr, const char *buf)
6516{
6517 struct tracer *t;
6518#ifdef CONFIG_TRACER_MAX_TRACE
6519 bool had_max_tr;
6520#endif
6521 int ret = 0;
6522
6523 mutex_lock(&trace_types_lock);
6524
6525 if (!tr->ring_buffer_expanded) {
6526 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6527 RING_BUFFER_ALL_CPUS);
6528 if (ret < 0)
6529 goto out;
6530 ret = 0;
6531 }
6532
6533 for (t = trace_types; t; t = t->next) {
6534 if (strcmp(t->name, buf) == 0)
6535 break;
6536 }
6537 if (!t) {
6538 ret = -EINVAL;
6539 goto out;
6540 }
6541 if (t == tr->current_trace)
6542 goto out;
6543
6544#ifdef CONFIG_TRACER_SNAPSHOT
6545 if (t->use_max_tr) {
6546 local_irq_disable();
6547 arch_spin_lock(&tr->max_lock);
6548 if (tr->cond_snapshot)
6549 ret = -EBUSY;
6550 arch_spin_unlock(&tr->max_lock);
6551 local_irq_enable();
6552 if (ret)
6553 goto out;
6554 }
6555#endif
6556 /* Some tracers won't work on kernel command line */
6557 if (system_state < SYSTEM_RUNNING && t->noboot) {
6558 pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
6559 t->name);
6560 goto out;
6561 }
6562
6563 /* Some tracers are only allowed for the top level buffer */
6564 if (!trace_ok_for_array(t, tr)) {
6565 ret = -EINVAL;
6566 goto out;
6567 }
6568
6569 /* If trace pipe files are being read, we can't change the tracer */
6570 if (tr->trace_ref) {
6571 ret = -EBUSY;
6572 goto out;
6573 }
6574
6575 trace_branch_disable();
6576
6577 tr->current_trace->enabled--;
6578
6579 if (tr->current_trace->reset)
6580 tr->current_trace->reset(tr);
6581
6582#ifdef CONFIG_TRACER_MAX_TRACE
6583 had_max_tr = tr->current_trace->use_max_tr;
6584
6585 /* Current trace needs to be nop_trace before synchronize_rcu */
6586 tr->current_trace = &nop_trace;
6587
6588 if (had_max_tr && !t->use_max_tr) {
6589 /*
6590 * We need to make sure that the update_max_tr sees that
6591 * current_trace changed to nop_trace to keep it from
6592 * swapping the buffers after we resize it.
6593 * The update_max_tr is called from interrupts disabled
6594 * so a synchronized_sched() is sufficient.
6595 */
6596 synchronize_rcu();
6597 free_snapshot(tr);
6598 }
6599
6600 if (t->use_max_tr && !tr->allocated_snapshot) {
6601 ret = tracing_alloc_snapshot_instance(tr);
6602 if (ret < 0)
6603 goto out;
6604 }
6605#else
6606 tr->current_trace = &nop_trace;
6607#endif
6608
6609 if (t->init) {
6610 ret = tracer_init(t, tr);
6611 if (ret)
6612 goto out;
6613 }
6614
6615 tr->current_trace = t;
6616 tr->current_trace->enabled++;
6617 trace_branch_enable(tr);
6618 out:
6619 mutex_unlock(&trace_types_lock);
6620
6621 return ret;
6622}
6623
6624static ssize_t
6625tracing_set_trace_write(struct file *filp, const char __user *ubuf,
6626 size_t cnt, loff_t *ppos)
6627{
6628 struct trace_array *tr = filp->private_data;
6629 char buf[MAX_TRACER_SIZE+1];
6630 char *name;
6631 size_t ret;
6632 int err;
6633
6634 ret = cnt;
6635
6636 if (cnt > MAX_TRACER_SIZE)
6637 cnt = MAX_TRACER_SIZE;
6638
6639 if (copy_from_user(buf, ubuf, cnt))
6640 return -EFAULT;
6641
6642 buf[cnt] = 0;
6643
6644 name = strim(buf);
6645
6646 err = tracing_set_tracer(tr, name);
6647 if (err)
6648 return err;
6649
6650 *ppos += ret;
6651
6652 return ret;
6653}
6654
6655static ssize_t
6656tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
6657 size_t cnt, loff_t *ppos)
6658{
6659 char buf[64];
6660 int r;
6661
6662 r = snprintf(buf, sizeof(buf), "%ld\n",
6663 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
6664 if (r > sizeof(buf))
6665 r = sizeof(buf);
6666 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6667}
6668
6669static ssize_t
6670tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
6671 size_t cnt, loff_t *ppos)
6672{
6673 unsigned long val;
6674 int ret;
6675
6676 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6677 if (ret)
6678 return ret;
6679
6680 *ptr = val * 1000;
6681
6682 return cnt;
6683}
6684
6685static ssize_t
6686tracing_thresh_read(struct file *filp, char __user *ubuf,
6687 size_t cnt, loff_t *ppos)
6688{
6689 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
6690}
6691
6692static ssize_t
6693tracing_thresh_write(struct file *filp, const char __user *ubuf,
6694 size_t cnt, loff_t *ppos)
6695{
6696 struct trace_array *tr = filp->private_data;
6697 int ret;
6698
6699 mutex_lock(&trace_types_lock);
6700 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
6701 if (ret < 0)
6702 goto out;
6703
6704 if (tr->current_trace->update_thresh) {
6705 ret = tr->current_trace->update_thresh(tr);
6706 if (ret < 0)
6707 goto out;
6708 }
6709
6710 ret = cnt;
6711out:
6712 mutex_unlock(&trace_types_lock);
6713
6714 return ret;
6715}
6716
6717#ifdef CONFIG_TRACER_MAX_TRACE
6718
6719static ssize_t
6720tracing_max_lat_read(struct file *filp, char __user *ubuf,
6721 size_t cnt, loff_t *ppos)
6722{
6723 struct trace_array *tr = filp->private_data;
6724
6725 return tracing_nsecs_read(&tr->max_latency, ubuf, cnt, ppos);
6726}
6727
6728static ssize_t
6729tracing_max_lat_write(struct file *filp, const char __user *ubuf,
6730 size_t cnt, loff_t *ppos)
6731{
6732 struct trace_array *tr = filp->private_data;
6733
6734 return tracing_nsecs_write(&tr->max_latency, ubuf, cnt, ppos);
6735}
6736
6737#endif
6738
6739static int open_pipe_on_cpu(struct trace_array *tr, int cpu)
6740{
6741 if (cpu == RING_BUFFER_ALL_CPUS) {
6742 if (cpumask_empty(tr->pipe_cpumask)) {
6743 cpumask_setall(tr->pipe_cpumask);
6744 return 0;
6745 }
6746 } else if (!cpumask_test_cpu(cpu, tr->pipe_cpumask)) {
6747 cpumask_set_cpu(cpu, tr->pipe_cpumask);
6748 return 0;
6749 }
6750 return -EBUSY;
6751}
6752
6753static void close_pipe_on_cpu(struct trace_array *tr, int cpu)
6754{
6755 if (cpu == RING_BUFFER_ALL_CPUS) {
6756 WARN_ON(!cpumask_full(tr->pipe_cpumask));
6757 cpumask_clear(tr->pipe_cpumask);
6758 } else {
6759 WARN_ON(!cpumask_test_cpu(cpu, tr->pipe_cpumask));
6760 cpumask_clear_cpu(cpu, tr->pipe_cpumask);
6761 }
6762}
6763
6764static int tracing_open_pipe(struct inode *inode, struct file *filp)
6765{
6766 struct trace_array *tr = inode->i_private;
6767 struct trace_iterator *iter;
6768 int cpu;
6769 int ret;
6770
6771 ret = tracing_check_open_get_tr(tr);
6772 if (ret)
6773 return ret;
6774
6775 mutex_lock(&trace_types_lock);
6776 cpu = tracing_get_cpu(inode);
6777 ret = open_pipe_on_cpu(tr, cpu);
6778 if (ret)
6779 goto fail_pipe_on_cpu;
6780
6781 /* create a buffer to store the information to pass to userspace */
6782 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
6783 if (!iter) {
6784 ret = -ENOMEM;
6785 goto fail_alloc_iter;
6786 }
6787
6788 trace_seq_init(&iter->seq);
6789 iter->trace = tr->current_trace;
6790
6791 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
6792 ret = -ENOMEM;
6793 goto fail;
6794 }
6795
6796 /* trace pipe does not show start of buffer */
6797 cpumask_setall(iter->started);
6798
6799 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
6800 iter->iter_flags |= TRACE_FILE_LAT_FMT;
6801
6802 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
6803 if (trace_clocks[tr->clock_id].in_ns)
6804 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
6805
6806 iter->tr = tr;
6807 iter->array_buffer = &tr->array_buffer;
6808 iter->cpu_file = cpu;
6809 mutex_init(&iter->mutex);
6810 filp->private_data = iter;
6811
6812 if (iter->trace->pipe_open)
6813 iter->trace->pipe_open(iter);
6814
6815 nonseekable_open(inode, filp);
6816
6817 tr->trace_ref++;
6818
6819 mutex_unlock(&trace_types_lock);
6820 return ret;
6821
6822fail:
6823 kfree(iter);
6824fail_alloc_iter:
6825 close_pipe_on_cpu(tr, cpu);
6826fail_pipe_on_cpu:
6827 __trace_array_put(tr);
6828 mutex_unlock(&trace_types_lock);
6829 return ret;
6830}
6831
6832static int tracing_release_pipe(struct inode *inode, struct file *file)
6833{
6834 struct trace_iterator *iter = file->private_data;
6835 struct trace_array *tr = inode->i_private;
6836
6837 mutex_lock(&trace_types_lock);
6838
6839 tr->trace_ref--;
6840
6841 if (iter->trace->pipe_close)
6842 iter->trace->pipe_close(iter);
6843 close_pipe_on_cpu(tr, iter->cpu_file);
6844 mutex_unlock(&trace_types_lock);
6845
6846 free_trace_iter_content(iter);
6847 kfree(iter);
6848
6849 trace_array_put(tr);
6850
6851 return 0;
6852}
6853
6854static __poll_t
6855trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
6856{
6857 struct trace_array *tr = iter->tr;
6858
6859 /* Iterators are static, they should be filled or empty */
6860 if (trace_buffer_iter(iter, iter->cpu_file))
6861 return EPOLLIN | EPOLLRDNORM;
6862
6863 if (tr->trace_flags & TRACE_ITER_BLOCK)
6864 /*
6865 * Always select as readable when in blocking mode
6866 */
6867 return EPOLLIN | EPOLLRDNORM;
6868 else
6869 return ring_buffer_poll_wait(iter->array_buffer->buffer, iter->cpu_file,
6870 filp, poll_table, iter->tr->buffer_percent);
6871}
6872
6873static __poll_t
6874tracing_poll_pipe(struct file *filp, poll_table *poll_table)
6875{
6876 struct trace_iterator *iter = filp->private_data;
6877
6878 return trace_poll(iter, filp, poll_table);
6879}
6880
6881/* Must be called with iter->mutex held. */
6882static int tracing_wait_pipe(struct file *filp)
6883{
6884 struct trace_iterator *iter = filp->private_data;
6885 int ret;
6886
6887 while (trace_empty(iter)) {
6888
6889 if ((filp->f_flags & O_NONBLOCK)) {
6890 return -EAGAIN;
6891 }
6892
6893 /*
6894 * We block until we read something and tracing is disabled.
6895 * We still block if tracing is disabled, but we have never
6896 * read anything. This allows a user to cat this file, and
6897 * then enable tracing. But after we have read something,
6898 * we give an EOF when tracing is again disabled.
6899 *
6900 * iter->pos will be 0 if we haven't read anything.
6901 */
6902 if (!tracer_tracing_is_on(iter->tr) && iter->pos)
6903 break;
6904
6905 mutex_unlock(&iter->mutex);
6906
6907 ret = wait_on_pipe(iter, 0);
6908
6909 mutex_lock(&iter->mutex);
6910
6911 if (ret)
6912 return ret;
6913 }
6914
6915 return 1;
6916}
6917
6918/*
6919 * Consumer reader.
6920 */
6921static ssize_t
6922tracing_read_pipe(struct file *filp, char __user *ubuf,
6923 size_t cnt, loff_t *ppos)
6924{
6925 struct trace_iterator *iter = filp->private_data;
6926 ssize_t sret;
6927
6928 /*
6929 * Avoid more than one consumer on a single file descriptor
6930 * This is just a matter of traces coherency, the ring buffer itself
6931 * is protected.
6932 */
6933 mutex_lock(&iter->mutex);
6934
6935 /* return any leftover data */
6936 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6937 if (sret != -EBUSY)
6938 goto out;
6939
6940 trace_seq_init(&iter->seq);
6941
6942 if (iter->trace->read) {
6943 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
6944 if (sret)
6945 goto out;
6946 }
6947
6948waitagain:
6949 sret = tracing_wait_pipe(filp);
6950 if (sret <= 0)
6951 goto out;
6952
6953 /* stop when tracing is finished */
6954 if (trace_empty(iter)) {
6955 sret = 0;
6956 goto out;
6957 }
6958
6959 if (cnt >= TRACE_SEQ_BUFFER_SIZE)
6960 cnt = TRACE_SEQ_BUFFER_SIZE - 1;
6961
6962 /* reset all but tr, trace, and overruns */
6963 trace_iterator_reset(iter);
6964 cpumask_clear(iter->started);
6965 trace_seq_init(&iter->seq);
6966
6967 trace_event_read_lock();
6968 trace_access_lock(iter->cpu_file);
6969 while (trace_find_next_entry_inc(iter) != NULL) {
6970 enum print_line_t ret;
6971 int save_len = iter->seq.seq.len;
6972
6973 ret = print_trace_line(iter);
6974 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6975 /*
6976 * If one print_trace_line() fills entire trace_seq in one shot,
6977 * trace_seq_to_user() will returns -EBUSY because save_len == 0,
6978 * In this case, we need to consume it, otherwise, loop will peek
6979 * this event next time, resulting in an infinite loop.
6980 */
6981 if (save_len == 0) {
6982 iter->seq.full = 0;
6983 trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
6984 trace_consume(iter);
6985 break;
6986 }
6987
6988 /* In other cases, don't print partial lines */
6989 iter->seq.seq.len = save_len;
6990 break;
6991 }
6992 if (ret != TRACE_TYPE_NO_CONSUME)
6993 trace_consume(iter);
6994
6995 if (trace_seq_used(&iter->seq) >= cnt)
6996 break;
6997
6998 /*
6999 * Setting the full flag means we reached the trace_seq buffer
7000 * size and we should leave by partial output condition above.
7001 * One of the trace_seq_* functions is not used properly.
7002 */
7003 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
7004 iter->ent->type);
7005 }
7006 trace_access_unlock(iter->cpu_file);
7007 trace_event_read_unlock();
7008
7009 /* Now copy what we have to the user */
7010 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
7011 if (iter->seq.readpos >= trace_seq_used(&iter->seq))
7012 trace_seq_init(&iter->seq);
7013
7014 /*
7015 * If there was nothing to send to user, in spite of consuming trace
7016 * entries, go back to wait for more entries.
7017 */
7018 if (sret == -EBUSY)
7019 goto waitagain;
7020
7021out:
7022 mutex_unlock(&iter->mutex);
7023
7024 return sret;
7025}
7026
7027static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
7028 unsigned int idx)
7029{
7030 __free_page(spd->pages[idx]);
7031}
7032
7033static size_t
7034tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
7035{
7036 size_t count;
7037 int save_len;
7038 int ret;
7039
7040 /* Seq buffer is page-sized, exactly what we need. */
7041 for (;;) {
7042 save_len = iter->seq.seq.len;
7043 ret = print_trace_line(iter);
7044
7045 if (trace_seq_has_overflowed(&iter->seq)) {
7046 iter->seq.seq.len = save_len;
7047 break;
7048 }
7049
7050 /*
7051 * This should not be hit, because it should only
7052 * be set if the iter->seq overflowed. But check it
7053 * anyway to be safe.
7054 */
7055 if (ret == TRACE_TYPE_PARTIAL_LINE) {
7056 iter->seq.seq.len = save_len;
7057 break;
7058 }
7059
7060 count = trace_seq_used(&iter->seq) - save_len;
7061 if (rem < count) {
7062 rem = 0;
7063 iter->seq.seq.len = save_len;
7064 break;
7065 }
7066
7067 if (ret != TRACE_TYPE_NO_CONSUME)
7068 trace_consume(iter);
7069 rem -= count;
7070 if (!trace_find_next_entry_inc(iter)) {
7071 rem = 0;
7072 iter->ent = NULL;
7073 break;
7074 }
7075 }
7076
7077 return rem;
7078}
7079
7080static ssize_t tracing_splice_read_pipe(struct file *filp,
7081 loff_t *ppos,
7082 struct pipe_inode_info *pipe,
7083 size_t len,
7084 unsigned int flags)
7085{
7086 struct page *pages_def[PIPE_DEF_BUFFERS];
7087 struct partial_page partial_def[PIPE_DEF_BUFFERS];
7088 struct trace_iterator *iter = filp->private_data;
7089 struct splice_pipe_desc spd = {
7090 .pages = pages_def,
7091 .partial = partial_def,
7092 .nr_pages = 0, /* This gets updated below. */
7093 .nr_pages_max = PIPE_DEF_BUFFERS,
7094 .ops = &default_pipe_buf_ops,
7095 .spd_release = tracing_spd_release_pipe,
7096 };
7097 ssize_t ret;
7098 size_t rem;
7099 unsigned int i;
7100
7101 if (splice_grow_spd(pipe, &spd))
7102 return -ENOMEM;
7103
7104 mutex_lock(&iter->mutex);
7105
7106 if (iter->trace->splice_read) {
7107 ret = iter->trace->splice_read(iter, filp,
7108 ppos, pipe, len, flags);
7109 if (ret)
7110 goto out_err;
7111 }
7112
7113 ret = tracing_wait_pipe(filp);
7114 if (ret <= 0)
7115 goto out_err;
7116
7117 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
7118 ret = -EFAULT;
7119 goto out_err;
7120 }
7121
7122 trace_event_read_lock();
7123 trace_access_lock(iter->cpu_file);
7124
7125 /* Fill as many pages as possible. */
7126 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
7127 spd.pages[i] = alloc_page(GFP_KERNEL);
7128 if (!spd.pages[i])
7129 break;
7130
7131 rem = tracing_fill_pipe_page(rem, iter);
7132
7133 /* Copy the data into the page, so we can start over. */
7134 ret = trace_seq_to_buffer(&iter->seq,
7135 page_address(spd.pages[i]),
7136 trace_seq_used(&iter->seq));
7137 if (ret < 0) {
7138 __free_page(spd.pages[i]);
7139 break;
7140 }
7141 spd.partial[i].offset = 0;
7142 spd.partial[i].len = trace_seq_used(&iter->seq);
7143
7144 trace_seq_init(&iter->seq);
7145 }
7146
7147 trace_access_unlock(iter->cpu_file);
7148 trace_event_read_unlock();
7149 mutex_unlock(&iter->mutex);
7150
7151 spd.nr_pages = i;
7152
7153 if (i)
7154 ret = splice_to_pipe(pipe, &spd);
7155 else
7156 ret = 0;
7157out:
7158 splice_shrink_spd(&spd);
7159 return ret;
7160
7161out_err:
7162 mutex_unlock(&iter->mutex);
7163 goto out;
7164}
7165
7166static ssize_t
7167tracing_entries_read(struct file *filp, char __user *ubuf,
7168 size_t cnt, loff_t *ppos)
7169{
7170 struct inode *inode = file_inode(filp);
7171 struct trace_array *tr = inode->i_private;
7172 int cpu = tracing_get_cpu(inode);
7173 char buf[64];
7174 int r = 0;
7175 ssize_t ret;
7176
7177 mutex_lock(&trace_types_lock);
7178
7179 if (cpu == RING_BUFFER_ALL_CPUS) {
7180 int cpu, buf_size_same;
7181 unsigned long size;
7182
7183 size = 0;
7184 buf_size_same = 1;
7185 /* check if all cpu sizes are same */
7186 for_each_tracing_cpu(cpu) {
7187 /* fill in the size from first enabled cpu */
7188 if (size == 0)
7189 size = per_cpu_ptr(tr->array_buffer.data, cpu)->entries;
7190 if (size != per_cpu_ptr(tr->array_buffer.data, cpu)->entries) {
7191 buf_size_same = 0;
7192 break;
7193 }
7194 }
7195
7196 if (buf_size_same) {
7197 if (!tr->ring_buffer_expanded)
7198 r = sprintf(buf, "%lu (expanded: %lu)\n",
7199 size >> 10,
7200 trace_buf_size >> 10);
7201 else
7202 r = sprintf(buf, "%lu\n", size >> 10);
7203 } else
7204 r = sprintf(buf, "X\n");
7205 } else
7206 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10);
7207
7208 mutex_unlock(&trace_types_lock);
7209
7210 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7211 return ret;
7212}
7213
7214static ssize_t
7215tracing_entries_write(struct file *filp, const char __user *ubuf,
7216 size_t cnt, loff_t *ppos)
7217{
7218 struct inode *inode = file_inode(filp);
7219 struct trace_array *tr = inode->i_private;
7220 unsigned long val;
7221 int ret;
7222
7223 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7224 if (ret)
7225 return ret;
7226
7227 /* must have at least 1 entry */
7228 if (!val)
7229 return -EINVAL;
7230
7231 /* value is in KB */
7232 val <<= 10;
7233 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
7234 if (ret < 0)
7235 return ret;
7236
7237 *ppos += cnt;
7238
7239 return cnt;
7240}
7241
7242static ssize_t
7243tracing_total_entries_read(struct file *filp, char __user *ubuf,
7244 size_t cnt, loff_t *ppos)
7245{
7246 struct trace_array *tr = filp->private_data;
7247 char buf[64];
7248 int r, cpu;
7249 unsigned long size = 0, expanded_size = 0;
7250
7251 mutex_lock(&trace_types_lock);
7252 for_each_tracing_cpu(cpu) {
7253 size += per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10;
7254 if (!tr->ring_buffer_expanded)
7255 expanded_size += trace_buf_size >> 10;
7256 }
7257 if (tr->ring_buffer_expanded)
7258 r = sprintf(buf, "%lu\n", size);
7259 else
7260 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
7261 mutex_unlock(&trace_types_lock);
7262
7263 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7264}
7265
7266static ssize_t
7267tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
7268 size_t cnt, loff_t *ppos)
7269{
7270 /*
7271 * There is no need to read what the user has written, this function
7272 * is just to make sure that there is no error when "echo" is used
7273 */
7274
7275 *ppos += cnt;
7276
7277 return cnt;
7278}
7279
7280static int
7281tracing_free_buffer_release(struct inode *inode, struct file *filp)
7282{
7283 struct trace_array *tr = inode->i_private;
7284
7285 /* disable tracing ? */
7286 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
7287 tracer_tracing_off(tr);
7288 /* resize the ring buffer to 0 */
7289 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
7290
7291 trace_array_put(tr);
7292
7293 return 0;
7294}
7295
7296#define TRACE_MARKER_MAX_SIZE 4096
7297
7298static ssize_t
7299tracing_mark_write(struct file *filp, const char __user *ubuf,
7300 size_t cnt, loff_t *fpos)
7301{
7302 struct trace_array *tr = filp->private_data;
7303 struct ring_buffer_event *event;
7304 enum event_trigger_type tt = ETT_NONE;
7305 struct trace_buffer *buffer;
7306 struct print_entry *entry;
7307 int meta_size;
7308 ssize_t written;
7309 size_t size;
7310 int len;
7311
7312/* Used in tracing_mark_raw_write() as well */
7313#define FAULTED_STR "<faulted>"
7314#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */
7315
7316 if (tracing_disabled)
7317 return -EINVAL;
7318
7319 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7320 return -EINVAL;
7321
7322 if ((ssize_t)cnt < 0)
7323 return -EINVAL;
7324
7325 if (cnt > TRACE_MARKER_MAX_SIZE)
7326 cnt = TRACE_MARKER_MAX_SIZE;
7327
7328 meta_size = sizeof(*entry) + 2; /* add '\0' and possible '\n' */
7329 again:
7330 size = cnt + meta_size;
7331
7332 /* If less than "<faulted>", then make sure we can still add that */
7333 if (cnt < FAULTED_SIZE)
7334 size += FAULTED_SIZE - cnt;
7335
7336 buffer = tr->array_buffer.buffer;
7337 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
7338 tracing_gen_ctx());
7339 if (unlikely(!event)) {
7340 /*
7341 * If the size was greater than what was allowed, then
7342 * make it smaller and try again.
7343 */
7344 if (size > ring_buffer_max_event_size(buffer)) {
7345 /* cnt < FAULTED size should never be bigger than max */
7346 if (WARN_ON_ONCE(cnt < FAULTED_SIZE))
7347 return -EBADF;
7348 cnt = ring_buffer_max_event_size(buffer) - meta_size;
7349 /* The above should only happen once */
7350 if (WARN_ON_ONCE(cnt + meta_size == size))
7351 return -EBADF;
7352 goto again;
7353 }
7354
7355 /* Ring buffer disabled, return as if not open for write */
7356 return -EBADF;
7357 }
7358
7359 entry = ring_buffer_event_data(event);
7360 entry->ip = _THIS_IP_;
7361
7362 len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
7363 if (len) {
7364 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7365 cnt = FAULTED_SIZE;
7366 written = -EFAULT;
7367 } else
7368 written = cnt;
7369
7370 if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
7371 /* do not add \n before testing triggers, but add \0 */
7372 entry->buf[cnt] = '\0';
7373 tt = event_triggers_call(tr->trace_marker_file, buffer, entry, event);
7374 }
7375
7376 if (entry->buf[cnt - 1] != '\n') {
7377 entry->buf[cnt] = '\n';
7378 entry->buf[cnt + 1] = '\0';
7379 } else
7380 entry->buf[cnt] = '\0';
7381
7382 if (static_branch_unlikely(&trace_marker_exports_enabled))
7383 ftrace_exports(event, TRACE_EXPORT_MARKER);
7384 __buffer_unlock_commit(buffer, event);
7385
7386 if (tt)
7387 event_triggers_post_call(tr->trace_marker_file, tt);
7388
7389 return written;
7390}
7391
7392static ssize_t
7393tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
7394 size_t cnt, loff_t *fpos)
7395{
7396 struct trace_array *tr = filp->private_data;
7397 struct ring_buffer_event *event;
7398 struct trace_buffer *buffer;
7399 struct raw_data_entry *entry;
7400 ssize_t written;
7401 int size;
7402 int len;
7403
7404#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
7405
7406 if (tracing_disabled)
7407 return -EINVAL;
7408
7409 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7410 return -EINVAL;
7411
7412 /* The marker must at least have a tag id */
7413 if (cnt < sizeof(unsigned int))
7414 return -EINVAL;
7415
7416 size = sizeof(*entry) + cnt;
7417 if (cnt < FAULT_SIZE_ID)
7418 size += FAULT_SIZE_ID - cnt;
7419
7420 buffer = tr->array_buffer.buffer;
7421
7422 if (size > ring_buffer_max_event_size(buffer))
7423 return -EINVAL;
7424
7425 event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
7426 tracing_gen_ctx());
7427 if (!event)
7428 /* Ring buffer disabled, return as if not open for write */
7429 return -EBADF;
7430
7431 entry = ring_buffer_event_data(event);
7432
7433 len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
7434 if (len) {
7435 entry->id = -1;
7436 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7437 written = -EFAULT;
7438 } else
7439 written = cnt;
7440
7441 __buffer_unlock_commit(buffer, event);
7442
7443 return written;
7444}
7445
7446static int tracing_clock_show(struct seq_file *m, void *v)
7447{
7448 struct trace_array *tr = m->private;
7449 int i;
7450
7451 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
7452 seq_printf(m,
7453 "%s%s%s%s", i ? " " : "",
7454 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
7455 i == tr->clock_id ? "]" : "");
7456 seq_putc(m, '\n');
7457
7458 return 0;
7459}
7460
7461int tracing_set_clock(struct trace_array *tr, const char *clockstr)
7462{
7463 int i;
7464
7465 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
7466 if (strcmp(trace_clocks[i].name, clockstr) == 0)
7467 break;
7468 }
7469 if (i == ARRAY_SIZE(trace_clocks))
7470 return -EINVAL;
7471
7472 mutex_lock(&trace_types_lock);
7473
7474 tr->clock_id = i;
7475
7476 ring_buffer_set_clock(tr->array_buffer.buffer, trace_clocks[i].func);
7477
7478 /*
7479 * New clock may not be consistent with the previous clock.
7480 * Reset the buffer so that it doesn't have incomparable timestamps.
7481 */
7482 tracing_reset_online_cpus(&tr->array_buffer);
7483
7484#ifdef CONFIG_TRACER_MAX_TRACE
7485 if (tr->max_buffer.buffer)
7486 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
7487 tracing_reset_online_cpus(&tr->max_buffer);
7488#endif
7489
7490 mutex_unlock(&trace_types_lock);
7491
7492 return 0;
7493}
7494
7495static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
7496 size_t cnt, loff_t *fpos)
7497{
7498 struct seq_file *m = filp->private_data;
7499 struct trace_array *tr = m->private;
7500 char buf[64];
7501 const char *clockstr;
7502 int ret;
7503
7504 if (cnt >= sizeof(buf))
7505 return -EINVAL;
7506
7507 if (copy_from_user(buf, ubuf, cnt))
7508 return -EFAULT;
7509
7510 buf[cnt] = 0;
7511
7512 clockstr = strstrip(buf);
7513
7514 ret = tracing_set_clock(tr, clockstr);
7515 if (ret)
7516 return ret;
7517
7518 *fpos += cnt;
7519
7520 return cnt;
7521}
7522
7523static int tracing_clock_open(struct inode *inode, struct file *file)
7524{
7525 struct trace_array *tr = inode->i_private;
7526 int ret;
7527
7528 ret = tracing_check_open_get_tr(tr);
7529 if (ret)
7530 return ret;
7531
7532 ret = single_open(file, tracing_clock_show, inode->i_private);
7533 if (ret < 0)
7534 trace_array_put(tr);
7535
7536 return ret;
7537}
7538
7539static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
7540{
7541 struct trace_array *tr = m->private;
7542
7543 mutex_lock(&trace_types_lock);
7544
7545 if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer))
7546 seq_puts(m, "delta [absolute]\n");
7547 else
7548 seq_puts(m, "[delta] absolute\n");
7549
7550 mutex_unlock(&trace_types_lock);
7551
7552 return 0;
7553}
7554
7555static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
7556{
7557 struct trace_array *tr = inode->i_private;
7558 int ret;
7559
7560 ret = tracing_check_open_get_tr(tr);
7561 if (ret)
7562 return ret;
7563
7564 ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
7565 if (ret < 0)
7566 trace_array_put(tr);
7567
7568 return ret;
7569}
7570
7571u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe)
7572{
7573 if (rbe == this_cpu_read(trace_buffered_event))
7574 return ring_buffer_time_stamp(buffer);
7575
7576 return ring_buffer_event_time_stamp(buffer, rbe);
7577}
7578
7579/*
7580 * Set or disable using the per CPU trace_buffer_event when possible.
7581 */
7582int tracing_set_filter_buffering(struct trace_array *tr, bool set)
7583{
7584 int ret = 0;
7585
7586 mutex_lock(&trace_types_lock);
7587
7588 if (set && tr->no_filter_buffering_ref++)
7589 goto out;
7590
7591 if (!set) {
7592 if (WARN_ON_ONCE(!tr->no_filter_buffering_ref)) {
7593 ret = -EINVAL;
7594 goto out;
7595 }
7596
7597 --tr->no_filter_buffering_ref;
7598 }
7599 out:
7600 mutex_unlock(&trace_types_lock);
7601
7602 return ret;
7603}
7604
7605struct ftrace_buffer_info {
7606 struct trace_iterator iter;
7607 void *spare;
7608 unsigned int spare_cpu;
7609 unsigned int spare_size;
7610 unsigned int read;
7611};
7612
7613#ifdef CONFIG_TRACER_SNAPSHOT
7614static int tracing_snapshot_open(struct inode *inode, struct file *file)
7615{
7616 struct trace_array *tr = inode->i_private;
7617 struct trace_iterator *iter;
7618 struct seq_file *m;
7619 int ret;
7620
7621 ret = tracing_check_open_get_tr(tr);
7622 if (ret)
7623 return ret;
7624
7625 if (file->f_mode & FMODE_READ) {
7626 iter = __tracing_open(inode, file, true);
7627 if (IS_ERR(iter))
7628 ret = PTR_ERR(iter);
7629 } else {
7630 /* Writes still need the seq_file to hold the private data */
7631 ret = -ENOMEM;
7632 m = kzalloc(sizeof(*m), GFP_KERNEL);
7633 if (!m)
7634 goto out;
7635 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
7636 if (!iter) {
7637 kfree(m);
7638 goto out;
7639 }
7640 ret = 0;
7641
7642 iter->tr = tr;
7643 iter->array_buffer = &tr->max_buffer;
7644 iter->cpu_file = tracing_get_cpu(inode);
7645 m->private = iter;
7646 file->private_data = m;
7647 }
7648out:
7649 if (ret < 0)
7650 trace_array_put(tr);
7651
7652 return ret;
7653}
7654
7655static void tracing_swap_cpu_buffer(void *tr)
7656{
7657 update_max_tr_single((struct trace_array *)tr, current, smp_processor_id());
7658}
7659
7660static ssize_t
7661tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
7662 loff_t *ppos)
7663{
7664 struct seq_file *m = filp->private_data;
7665 struct trace_iterator *iter = m->private;
7666 struct trace_array *tr = iter->tr;
7667 unsigned long val;
7668 int ret;
7669
7670 ret = tracing_update_buffers(tr);
7671 if (ret < 0)
7672 return ret;
7673
7674 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7675 if (ret)
7676 return ret;
7677
7678 mutex_lock(&trace_types_lock);
7679
7680 if (tr->current_trace->use_max_tr) {
7681 ret = -EBUSY;
7682 goto out;
7683 }
7684
7685 local_irq_disable();
7686 arch_spin_lock(&tr->max_lock);
7687 if (tr->cond_snapshot)
7688 ret = -EBUSY;
7689 arch_spin_unlock(&tr->max_lock);
7690 local_irq_enable();
7691 if (ret)
7692 goto out;
7693
7694 switch (val) {
7695 case 0:
7696 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7697 ret = -EINVAL;
7698 break;
7699 }
7700 if (tr->allocated_snapshot)
7701 free_snapshot(tr);
7702 break;
7703 case 1:
7704/* Only allow per-cpu swap if the ring buffer supports it */
7705#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
7706 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7707 ret = -EINVAL;
7708 break;
7709 }
7710#endif
7711 if (tr->allocated_snapshot)
7712 ret = resize_buffer_duplicate_size(&tr->max_buffer,
7713 &tr->array_buffer, iter->cpu_file);
7714 else
7715 ret = tracing_alloc_snapshot_instance(tr);
7716 if (ret < 0)
7717 break;
7718 /* Now, we're going to swap */
7719 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
7720 local_irq_disable();
7721 update_max_tr(tr, current, smp_processor_id(), NULL);
7722 local_irq_enable();
7723 } else {
7724 smp_call_function_single(iter->cpu_file, tracing_swap_cpu_buffer,
7725 (void *)tr, 1);
7726 }
7727 break;
7728 default:
7729 if (tr->allocated_snapshot) {
7730 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
7731 tracing_reset_online_cpus(&tr->max_buffer);
7732 else
7733 tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
7734 }
7735 break;
7736 }
7737
7738 if (ret >= 0) {
7739 *ppos += cnt;
7740 ret = cnt;
7741 }
7742out:
7743 mutex_unlock(&trace_types_lock);
7744 return ret;
7745}
7746
7747static int tracing_snapshot_release(struct inode *inode, struct file *file)
7748{
7749 struct seq_file *m = file->private_data;
7750 int ret;
7751
7752 ret = tracing_release(inode, file);
7753
7754 if (file->f_mode & FMODE_READ)
7755 return ret;
7756
7757 /* If write only, the seq_file is just a stub */
7758 if (m)
7759 kfree(m->private);
7760 kfree(m);
7761
7762 return 0;
7763}
7764
7765static int tracing_buffers_open(struct inode *inode, struct file *filp);
7766static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
7767 size_t count, loff_t *ppos);
7768static int tracing_buffers_release(struct inode *inode, struct file *file);
7769static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
7770 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
7771
7772static int snapshot_raw_open(struct inode *inode, struct file *filp)
7773{
7774 struct ftrace_buffer_info *info;
7775 int ret;
7776
7777 /* The following checks for tracefs lockdown */
7778 ret = tracing_buffers_open(inode, filp);
7779 if (ret < 0)
7780 return ret;
7781
7782 info = filp->private_data;
7783
7784 if (info->iter.trace->use_max_tr) {
7785 tracing_buffers_release(inode, filp);
7786 return -EBUSY;
7787 }
7788
7789 info->iter.snapshot = true;
7790 info->iter.array_buffer = &info->iter.tr->max_buffer;
7791
7792 return ret;
7793}
7794
7795#endif /* CONFIG_TRACER_SNAPSHOT */
7796
7797
7798static const struct file_operations tracing_thresh_fops = {
7799 .open = tracing_open_generic,
7800 .read = tracing_thresh_read,
7801 .write = tracing_thresh_write,
7802 .llseek = generic_file_llseek,
7803};
7804
7805#ifdef CONFIG_TRACER_MAX_TRACE
7806static const struct file_operations tracing_max_lat_fops = {
7807 .open = tracing_open_generic_tr,
7808 .read = tracing_max_lat_read,
7809 .write = tracing_max_lat_write,
7810 .llseek = generic_file_llseek,
7811 .release = tracing_release_generic_tr,
7812};
7813#endif
7814
7815static const struct file_operations set_tracer_fops = {
7816 .open = tracing_open_generic_tr,
7817 .read = tracing_set_trace_read,
7818 .write = tracing_set_trace_write,
7819 .llseek = generic_file_llseek,
7820 .release = tracing_release_generic_tr,
7821};
7822
7823static const struct file_operations tracing_pipe_fops = {
7824 .open = tracing_open_pipe,
7825 .poll = tracing_poll_pipe,
7826 .read = tracing_read_pipe,
7827 .splice_read = tracing_splice_read_pipe,
7828 .release = tracing_release_pipe,
7829 .llseek = no_llseek,
7830};
7831
7832static const struct file_operations tracing_entries_fops = {
7833 .open = tracing_open_generic_tr,
7834 .read = tracing_entries_read,
7835 .write = tracing_entries_write,
7836 .llseek = generic_file_llseek,
7837 .release = tracing_release_generic_tr,
7838};
7839
7840static const struct file_operations tracing_total_entries_fops = {
7841 .open = tracing_open_generic_tr,
7842 .read = tracing_total_entries_read,
7843 .llseek = generic_file_llseek,
7844 .release = tracing_release_generic_tr,
7845};
7846
7847static const struct file_operations tracing_free_buffer_fops = {
7848 .open = tracing_open_generic_tr,
7849 .write = tracing_free_buffer_write,
7850 .release = tracing_free_buffer_release,
7851};
7852
7853static const struct file_operations tracing_mark_fops = {
7854 .open = tracing_mark_open,
7855 .write = tracing_mark_write,
7856 .release = tracing_release_generic_tr,
7857};
7858
7859static const struct file_operations tracing_mark_raw_fops = {
7860 .open = tracing_mark_open,
7861 .write = tracing_mark_raw_write,
7862 .release = tracing_release_generic_tr,
7863};
7864
7865static const struct file_operations trace_clock_fops = {
7866 .open = tracing_clock_open,
7867 .read = seq_read,
7868 .llseek = seq_lseek,
7869 .release = tracing_single_release_tr,
7870 .write = tracing_clock_write,
7871};
7872
7873static const struct file_operations trace_time_stamp_mode_fops = {
7874 .open = tracing_time_stamp_mode_open,
7875 .read = seq_read,
7876 .llseek = seq_lseek,
7877 .release = tracing_single_release_tr,
7878};
7879
7880#ifdef CONFIG_TRACER_SNAPSHOT
7881static const struct file_operations snapshot_fops = {
7882 .open = tracing_snapshot_open,
7883 .read = seq_read,
7884 .write = tracing_snapshot_write,
7885 .llseek = tracing_lseek,
7886 .release = tracing_snapshot_release,
7887};
7888
7889static const struct file_operations snapshot_raw_fops = {
7890 .open = snapshot_raw_open,
7891 .read = tracing_buffers_read,
7892 .release = tracing_buffers_release,
7893 .splice_read = tracing_buffers_splice_read,
7894 .llseek = no_llseek,
7895};
7896
7897#endif /* CONFIG_TRACER_SNAPSHOT */
7898
7899/*
7900 * trace_min_max_write - Write a u64 value to a trace_min_max_param struct
7901 * @filp: The active open file structure
7902 * @ubuf: The userspace provided buffer to read value into
7903 * @cnt: The maximum number of bytes to read
7904 * @ppos: The current "file" position
7905 *
7906 * This function implements the write interface for a struct trace_min_max_param.
7907 * The filp->private_data must point to a trace_min_max_param structure that
7908 * defines where to write the value, the min and the max acceptable values,
7909 * and a lock to protect the write.
7910 */
7911static ssize_t
7912trace_min_max_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos)
7913{
7914 struct trace_min_max_param *param = filp->private_data;
7915 u64 val;
7916 int err;
7917
7918 if (!param)
7919 return -EFAULT;
7920
7921 err = kstrtoull_from_user(ubuf, cnt, 10, &val);
7922 if (err)
7923 return err;
7924
7925 if (param->lock)
7926 mutex_lock(param->lock);
7927
7928 if (param->min && val < *param->min)
7929 err = -EINVAL;
7930
7931 if (param->max && val > *param->max)
7932 err = -EINVAL;
7933
7934 if (!err)
7935 *param->val = val;
7936
7937 if (param->lock)
7938 mutex_unlock(param->lock);
7939
7940 if (err)
7941 return err;
7942
7943 return cnt;
7944}
7945
7946/*
7947 * trace_min_max_read - Read a u64 value from a trace_min_max_param struct
7948 * @filp: The active open file structure
7949 * @ubuf: The userspace provided buffer to read value into
7950 * @cnt: The maximum number of bytes to read
7951 * @ppos: The current "file" position
7952 *
7953 * This function implements the read interface for a struct trace_min_max_param.
7954 * The filp->private_data must point to a trace_min_max_param struct with valid
7955 * data.
7956 */
7957static ssize_t
7958trace_min_max_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
7959{
7960 struct trace_min_max_param *param = filp->private_data;
7961 char buf[U64_STR_SIZE];
7962 int len;
7963 u64 val;
7964
7965 if (!param)
7966 return -EFAULT;
7967
7968 val = *param->val;
7969
7970 if (cnt > sizeof(buf))
7971 cnt = sizeof(buf);
7972
7973 len = snprintf(buf, sizeof(buf), "%llu\n", val);
7974
7975 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
7976}
7977
7978const struct file_operations trace_min_max_fops = {
7979 .open = tracing_open_generic,
7980 .read = trace_min_max_read,
7981 .write = trace_min_max_write,
7982};
7983
7984#define TRACING_LOG_ERRS_MAX 8
7985#define TRACING_LOG_LOC_MAX 128
7986
7987#define CMD_PREFIX " Command: "
7988
7989struct err_info {
7990 const char **errs; /* ptr to loc-specific array of err strings */
7991 u8 type; /* index into errs -> specific err string */
7992 u16 pos; /* caret position */
7993 u64 ts;
7994};
7995
7996struct tracing_log_err {
7997 struct list_head list;
7998 struct err_info info;
7999 char loc[TRACING_LOG_LOC_MAX]; /* err location */
8000 char *cmd; /* what caused err */
8001};
8002
8003static DEFINE_MUTEX(tracing_err_log_lock);
8004
8005static struct tracing_log_err *alloc_tracing_log_err(int len)
8006{
8007 struct tracing_log_err *err;
8008
8009 err = kzalloc(sizeof(*err), GFP_KERNEL);
8010 if (!err)
8011 return ERR_PTR(-ENOMEM);
8012
8013 err->cmd = kzalloc(len, GFP_KERNEL);
8014 if (!err->cmd) {
8015 kfree(err);
8016 return ERR_PTR(-ENOMEM);
8017 }
8018
8019 return err;
8020}
8021
8022static void free_tracing_log_err(struct tracing_log_err *err)
8023{
8024 kfree(err->cmd);
8025 kfree(err);
8026}
8027
8028static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr,
8029 int len)
8030{
8031 struct tracing_log_err *err;
8032 char *cmd;
8033
8034 if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
8035 err = alloc_tracing_log_err(len);
8036 if (PTR_ERR(err) != -ENOMEM)
8037 tr->n_err_log_entries++;
8038
8039 return err;
8040 }
8041 cmd = kzalloc(len, GFP_KERNEL);
8042 if (!cmd)
8043 return ERR_PTR(-ENOMEM);
8044 err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
8045 kfree(err->cmd);
8046 err->cmd = cmd;
8047 list_del(&err->list);
8048
8049 return err;
8050}
8051
8052/**
8053 * err_pos - find the position of a string within a command for error careting
8054 * @cmd: The tracing command that caused the error
8055 * @str: The string to position the caret at within @cmd
8056 *
8057 * Finds the position of the first occurrence of @str within @cmd. The
8058 * return value can be passed to tracing_log_err() for caret placement
8059 * within @cmd.
8060 *
8061 * Returns the index within @cmd of the first occurrence of @str or 0
8062 * if @str was not found.
8063 */
8064unsigned int err_pos(char *cmd, const char *str)
8065{
8066 char *found;
8067
8068 if (WARN_ON(!strlen(cmd)))
8069 return 0;
8070
8071 found = strstr(cmd, str);
8072 if (found)
8073 return found - cmd;
8074
8075 return 0;
8076}
8077
8078/**
8079 * tracing_log_err - write an error to the tracing error log
8080 * @tr: The associated trace array for the error (NULL for top level array)
8081 * @loc: A string describing where the error occurred
8082 * @cmd: The tracing command that caused the error
8083 * @errs: The array of loc-specific static error strings
8084 * @type: The index into errs[], which produces the specific static err string
8085 * @pos: The position the caret should be placed in the cmd
8086 *
8087 * Writes an error into tracing/error_log of the form:
8088 *
8089 * <loc>: error: <text>
8090 * Command: <cmd>
8091 * ^
8092 *
8093 * tracing/error_log is a small log file containing the last
8094 * TRACING_LOG_ERRS_MAX errors (8). Memory for errors isn't allocated
8095 * unless there has been a tracing error, and the error log can be
8096 * cleared and have its memory freed by writing the empty string in
8097 * truncation mode to it i.e. echo > tracing/error_log.
8098 *
8099 * NOTE: the @errs array along with the @type param are used to
8100 * produce a static error string - this string is not copied and saved
8101 * when the error is logged - only a pointer to it is saved. See
8102 * existing callers for examples of how static strings are typically
8103 * defined for use with tracing_log_err().
8104 */
8105void tracing_log_err(struct trace_array *tr,
8106 const char *loc, const char *cmd,
8107 const char **errs, u8 type, u16 pos)
8108{
8109 struct tracing_log_err *err;
8110 int len = 0;
8111
8112 if (!tr)
8113 tr = &global_trace;
8114
8115 len += sizeof(CMD_PREFIX) + 2 * sizeof("\n") + strlen(cmd) + 1;
8116
8117 mutex_lock(&tracing_err_log_lock);
8118 err = get_tracing_log_err(tr, len);
8119 if (PTR_ERR(err) == -ENOMEM) {
8120 mutex_unlock(&tracing_err_log_lock);
8121 return;
8122 }
8123
8124 snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
8125 snprintf(err->cmd, len, "\n" CMD_PREFIX "%s\n", cmd);
8126
8127 err->info.errs = errs;
8128 err->info.type = type;
8129 err->info.pos = pos;
8130 err->info.ts = local_clock();
8131
8132 list_add_tail(&err->list, &tr->err_log);
8133 mutex_unlock(&tracing_err_log_lock);
8134}
8135
8136static void clear_tracing_err_log(struct trace_array *tr)
8137{
8138 struct tracing_log_err *err, *next;
8139
8140 mutex_lock(&tracing_err_log_lock);
8141 list_for_each_entry_safe(err, next, &tr->err_log, list) {
8142 list_del(&err->list);
8143 free_tracing_log_err(err);
8144 }
8145
8146 tr->n_err_log_entries = 0;
8147 mutex_unlock(&tracing_err_log_lock);
8148}
8149
8150static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
8151{
8152 struct trace_array *tr = m->private;
8153
8154 mutex_lock(&tracing_err_log_lock);
8155
8156 return seq_list_start(&tr->err_log, *pos);
8157}
8158
8159static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos)
8160{
8161 struct trace_array *tr = m->private;
8162
8163 return seq_list_next(v, &tr->err_log, pos);
8164}
8165
8166static void tracing_err_log_seq_stop(struct seq_file *m, void *v)
8167{
8168 mutex_unlock(&tracing_err_log_lock);
8169}
8170
8171static void tracing_err_log_show_pos(struct seq_file *m, u16 pos)
8172{
8173 u16 i;
8174
8175 for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++)
8176 seq_putc(m, ' ');
8177 for (i = 0; i < pos; i++)
8178 seq_putc(m, ' ');
8179 seq_puts(m, "^\n");
8180}
8181
8182static int tracing_err_log_seq_show(struct seq_file *m, void *v)
8183{
8184 struct tracing_log_err *err = v;
8185
8186 if (err) {
8187 const char *err_text = err->info.errs[err->info.type];
8188 u64 sec = err->info.ts;
8189 u32 nsec;
8190
8191 nsec = do_div(sec, NSEC_PER_SEC);
8192 seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000,
8193 err->loc, err_text);
8194 seq_printf(m, "%s", err->cmd);
8195 tracing_err_log_show_pos(m, err->info.pos);
8196 }
8197
8198 return 0;
8199}
8200
8201static const struct seq_operations tracing_err_log_seq_ops = {
8202 .start = tracing_err_log_seq_start,
8203 .next = tracing_err_log_seq_next,
8204 .stop = tracing_err_log_seq_stop,
8205 .show = tracing_err_log_seq_show
8206};
8207
8208static int tracing_err_log_open(struct inode *inode, struct file *file)
8209{
8210 struct trace_array *tr = inode->i_private;
8211 int ret = 0;
8212
8213 ret = tracing_check_open_get_tr(tr);
8214 if (ret)
8215 return ret;
8216
8217 /* If this file was opened for write, then erase contents */
8218 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
8219 clear_tracing_err_log(tr);
8220
8221 if (file->f_mode & FMODE_READ) {
8222 ret = seq_open(file, &tracing_err_log_seq_ops);
8223 if (!ret) {
8224 struct seq_file *m = file->private_data;
8225 m->private = tr;
8226 } else {
8227 trace_array_put(tr);
8228 }
8229 }
8230 return ret;
8231}
8232
8233static ssize_t tracing_err_log_write(struct file *file,
8234 const char __user *buffer,
8235 size_t count, loff_t *ppos)
8236{
8237 return count;
8238}
8239
8240static int tracing_err_log_release(struct inode *inode, struct file *file)
8241{
8242 struct trace_array *tr = inode->i_private;
8243
8244 trace_array_put(tr);
8245
8246 if (file->f_mode & FMODE_READ)
8247 seq_release(inode, file);
8248
8249 return 0;
8250}
8251
8252static const struct file_operations tracing_err_log_fops = {
8253 .open = tracing_err_log_open,
8254 .write = tracing_err_log_write,
8255 .read = seq_read,
8256 .llseek = tracing_lseek,
8257 .release = tracing_err_log_release,
8258};
8259
8260static int tracing_buffers_open(struct inode *inode, struct file *filp)
8261{
8262 struct trace_array *tr = inode->i_private;
8263 struct ftrace_buffer_info *info;
8264 int ret;
8265
8266 ret = tracing_check_open_get_tr(tr);
8267 if (ret)
8268 return ret;
8269
8270 info = kvzalloc(sizeof(*info), GFP_KERNEL);
8271 if (!info) {
8272 trace_array_put(tr);
8273 return -ENOMEM;
8274 }
8275
8276 mutex_lock(&trace_types_lock);
8277
8278 info->iter.tr = tr;
8279 info->iter.cpu_file = tracing_get_cpu(inode);
8280 info->iter.trace = tr->current_trace;
8281 info->iter.array_buffer = &tr->array_buffer;
8282 info->spare = NULL;
8283 /* Force reading ring buffer for first read */
8284 info->read = (unsigned int)-1;
8285
8286 filp->private_data = info;
8287
8288 tr->trace_ref++;
8289
8290 mutex_unlock(&trace_types_lock);
8291
8292 ret = nonseekable_open(inode, filp);
8293 if (ret < 0)
8294 trace_array_put(tr);
8295
8296 return ret;
8297}
8298
8299static __poll_t
8300tracing_buffers_poll(struct file *filp, poll_table *poll_table)
8301{
8302 struct ftrace_buffer_info *info = filp->private_data;
8303 struct trace_iterator *iter = &info->iter;
8304
8305 return trace_poll(iter, filp, poll_table);
8306}
8307
8308static ssize_t
8309tracing_buffers_read(struct file *filp, char __user *ubuf,
8310 size_t count, loff_t *ppos)
8311{
8312 struct ftrace_buffer_info *info = filp->private_data;
8313 struct trace_iterator *iter = &info->iter;
8314 void *trace_data;
8315 int page_size;
8316 ssize_t ret = 0;
8317 ssize_t size;
8318
8319 if (!count)
8320 return 0;
8321
8322#ifdef CONFIG_TRACER_MAX_TRACE
8323 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8324 return -EBUSY;
8325#endif
8326
8327 page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
8328
8329 /* Make sure the spare matches the current sub buffer size */
8330 if (info->spare) {
8331 if (page_size != info->spare_size) {
8332 ring_buffer_free_read_page(iter->array_buffer->buffer,
8333 info->spare_cpu, info->spare);
8334 info->spare = NULL;
8335 }
8336 }
8337
8338 if (!info->spare) {
8339 info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer,
8340 iter->cpu_file);
8341 if (IS_ERR(info->spare)) {
8342 ret = PTR_ERR(info->spare);
8343 info->spare = NULL;
8344 } else {
8345 info->spare_cpu = iter->cpu_file;
8346 info->spare_size = page_size;
8347 }
8348 }
8349 if (!info->spare)
8350 return ret;
8351
8352 /* Do we have previous read data to read? */
8353 if (info->read < page_size)
8354 goto read;
8355
8356 again:
8357 trace_access_lock(iter->cpu_file);
8358 ret = ring_buffer_read_page(iter->array_buffer->buffer,
8359 info->spare,
8360 count,
8361 iter->cpu_file, 0);
8362 trace_access_unlock(iter->cpu_file);
8363
8364 if (ret < 0) {
8365 if (trace_empty(iter)) {
8366 if ((filp->f_flags & O_NONBLOCK))
8367 return -EAGAIN;
8368
8369 ret = wait_on_pipe(iter, 0);
8370 if (ret)
8371 return ret;
8372
8373 goto again;
8374 }
8375 return 0;
8376 }
8377
8378 info->read = 0;
8379 read:
8380 size = page_size - info->read;
8381 if (size > count)
8382 size = count;
8383 trace_data = ring_buffer_read_page_data(info->spare);
8384 ret = copy_to_user(ubuf, trace_data + info->read, size);
8385 if (ret == size)
8386 return -EFAULT;
8387
8388 size -= ret;
8389
8390 *ppos += size;
8391 info->read += size;
8392
8393 return size;
8394}
8395
8396static int tracing_buffers_flush(struct file *file, fl_owner_t id)
8397{
8398 struct ftrace_buffer_info *info = file->private_data;
8399 struct trace_iterator *iter = &info->iter;
8400
8401 iter->wait_index++;
8402 /* Make sure the waiters see the new wait_index */
8403 smp_wmb();
8404
8405 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
8406
8407 return 0;
8408}
8409
8410static int tracing_buffers_release(struct inode *inode, struct file *file)
8411{
8412 struct ftrace_buffer_info *info = file->private_data;
8413 struct trace_iterator *iter = &info->iter;
8414
8415 mutex_lock(&trace_types_lock);
8416
8417 iter->tr->trace_ref--;
8418
8419 __trace_array_put(iter->tr);
8420
8421 if (info->spare)
8422 ring_buffer_free_read_page(iter->array_buffer->buffer,
8423 info->spare_cpu, info->spare);
8424 kvfree(info);
8425
8426 mutex_unlock(&trace_types_lock);
8427
8428 return 0;
8429}
8430
8431struct buffer_ref {
8432 struct trace_buffer *buffer;
8433 void *page;
8434 int cpu;
8435 refcount_t refcount;
8436};
8437
8438static void buffer_ref_release(struct buffer_ref *ref)
8439{
8440 if (!refcount_dec_and_test(&ref->refcount))
8441 return;
8442 ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
8443 kfree(ref);
8444}
8445
8446static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
8447 struct pipe_buffer *buf)
8448{
8449 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8450
8451 buffer_ref_release(ref);
8452 buf->private = 0;
8453}
8454
8455static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
8456 struct pipe_buffer *buf)
8457{
8458 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8459
8460 if (refcount_read(&ref->refcount) > INT_MAX/2)
8461 return false;
8462
8463 refcount_inc(&ref->refcount);
8464 return true;
8465}
8466
8467/* Pipe buffer operations for a buffer. */
8468static const struct pipe_buf_operations buffer_pipe_buf_ops = {
8469 .release = buffer_pipe_buf_release,
8470 .get = buffer_pipe_buf_get,
8471};
8472
8473/*
8474 * Callback from splice_to_pipe(), if we need to release some pages
8475 * at the end of the spd in case we error'ed out in filling the pipe.
8476 */
8477static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
8478{
8479 struct buffer_ref *ref =
8480 (struct buffer_ref *)spd->partial[i].private;
8481
8482 buffer_ref_release(ref);
8483 spd->partial[i].private = 0;
8484}
8485
8486static ssize_t
8487tracing_buffers_splice_read(struct file *file, loff_t *ppos,
8488 struct pipe_inode_info *pipe, size_t len,
8489 unsigned int flags)
8490{
8491 struct ftrace_buffer_info *info = file->private_data;
8492 struct trace_iterator *iter = &info->iter;
8493 struct partial_page partial_def[PIPE_DEF_BUFFERS];
8494 struct page *pages_def[PIPE_DEF_BUFFERS];
8495 struct splice_pipe_desc spd = {
8496 .pages = pages_def,
8497 .partial = partial_def,
8498 .nr_pages_max = PIPE_DEF_BUFFERS,
8499 .ops = &buffer_pipe_buf_ops,
8500 .spd_release = buffer_spd_release,
8501 };
8502 struct buffer_ref *ref;
8503 int page_size;
8504 int entries, i;
8505 ssize_t ret = 0;
8506
8507#ifdef CONFIG_TRACER_MAX_TRACE
8508 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8509 return -EBUSY;
8510#endif
8511
8512 page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
8513 if (*ppos & (page_size - 1))
8514 return -EINVAL;
8515
8516 if (len & (page_size - 1)) {
8517 if (len < page_size)
8518 return -EINVAL;
8519 len &= (~(page_size - 1));
8520 }
8521
8522 if (splice_grow_spd(pipe, &spd))
8523 return -ENOMEM;
8524
8525 again:
8526 trace_access_lock(iter->cpu_file);
8527 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8528
8529 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= page_size) {
8530 struct page *page;
8531 int r;
8532
8533 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
8534 if (!ref) {
8535 ret = -ENOMEM;
8536 break;
8537 }
8538
8539 refcount_set(&ref->refcount, 1);
8540 ref->buffer = iter->array_buffer->buffer;
8541 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
8542 if (IS_ERR(ref->page)) {
8543 ret = PTR_ERR(ref->page);
8544 ref->page = NULL;
8545 kfree(ref);
8546 break;
8547 }
8548 ref->cpu = iter->cpu_file;
8549
8550 r = ring_buffer_read_page(ref->buffer, ref->page,
8551 len, iter->cpu_file, 1);
8552 if (r < 0) {
8553 ring_buffer_free_read_page(ref->buffer, ref->cpu,
8554 ref->page);
8555 kfree(ref);
8556 break;
8557 }
8558
8559 page = virt_to_page(ring_buffer_read_page_data(ref->page));
8560
8561 spd.pages[i] = page;
8562 spd.partial[i].len = page_size;
8563 spd.partial[i].offset = 0;
8564 spd.partial[i].private = (unsigned long)ref;
8565 spd.nr_pages++;
8566 *ppos += page_size;
8567
8568 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8569 }
8570
8571 trace_access_unlock(iter->cpu_file);
8572 spd.nr_pages = i;
8573
8574 /* did we read anything? */
8575 if (!spd.nr_pages) {
8576 long wait_index;
8577
8578 if (ret)
8579 goto out;
8580
8581 ret = -EAGAIN;
8582 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
8583 goto out;
8584
8585 wait_index = READ_ONCE(iter->wait_index);
8586
8587 ret = wait_on_pipe(iter, iter->snapshot ? 0 : iter->tr->buffer_percent);
8588 if (ret)
8589 goto out;
8590
8591 /* No need to wait after waking up when tracing is off */
8592 if (!tracer_tracing_is_on(iter->tr))
8593 goto out;
8594
8595 /* Make sure we see the new wait_index */
8596 smp_rmb();
8597 if (wait_index != iter->wait_index)
8598 goto out;
8599
8600 goto again;
8601 }
8602
8603 ret = splice_to_pipe(pipe, &spd);
8604out:
8605 splice_shrink_spd(&spd);
8606
8607 return ret;
8608}
8609
8610/* An ioctl call with cmd 0 to the ring buffer file will wake up all waiters */
8611static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
8612{
8613 struct ftrace_buffer_info *info = file->private_data;
8614 struct trace_iterator *iter = &info->iter;
8615
8616 if (cmd)
8617 return -ENOIOCTLCMD;
8618
8619 mutex_lock(&trace_types_lock);
8620
8621 iter->wait_index++;
8622 /* Make sure the waiters see the new wait_index */
8623 smp_wmb();
8624
8625 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
8626
8627 mutex_unlock(&trace_types_lock);
8628 return 0;
8629}
8630
8631static const struct file_operations tracing_buffers_fops = {
8632 .open = tracing_buffers_open,
8633 .read = tracing_buffers_read,
8634 .poll = tracing_buffers_poll,
8635 .release = tracing_buffers_release,
8636 .flush = tracing_buffers_flush,
8637 .splice_read = tracing_buffers_splice_read,
8638 .unlocked_ioctl = tracing_buffers_ioctl,
8639 .llseek = no_llseek,
8640};
8641
8642static ssize_t
8643tracing_stats_read(struct file *filp, char __user *ubuf,
8644 size_t count, loff_t *ppos)
8645{
8646 struct inode *inode = file_inode(filp);
8647 struct trace_array *tr = inode->i_private;
8648 struct array_buffer *trace_buf = &tr->array_buffer;
8649 int cpu = tracing_get_cpu(inode);
8650 struct trace_seq *s;
8651 unsigned long cnt;
8652 unsigned long long t;
8653 unsigned long usec_rem;
8654
8655 s = kmalloc(sizeof(*s), GFP_KERNEL);
8656 if (!s)
8657 return -ENOMEM;
8658
8659 trace_seq_init(s);
8660
8661 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
8662 trace_seq_printf(s, "entries: %ld\n", cnt);
8663
8664 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
8665 trace_seq_printf(s, "overrun: %ld\n", cnt);
8666
8667 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
8668 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
8669
8670 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
8671 trace_seq_printf(s, "bytes: %ld\n", cnt);
8672
8673 if (trace_clocks[tr->clock_id].in_ns) {
8674 /* local or global for trace_clock */
8675 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8676 usec_rem = do_div(t, USEC_PER_SEC);
8677 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
8678 t, usec_rem);
8679
8680 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer));
8681 usec_rem = do_div(t, USEC_PER_SEC);
8682 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
8683 } else {
8684 /* counter or tsc mode for trace_clock */
8685 trace_seq_printf(s, "oldest event ts: %llu\n",
8686 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8687
8688 trace_seq_printf(s, "now ts: %llu\n",
8689 ring_buffer_time_stamp(trace_buf->buffer));
8690 }
8691
8692 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
8693 trace_seq_printf(s, "dropped events: %ld\n", cnt);
8694
8695 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
8696 trace_seq_printf(s, "read events: %ld\n", cnt);
8697
8698 count = simple_read_from_buffer(ubuf, count, ppos,
8699 s->buffer, trace_seq_used(s));
8700
8701 kfree(s);
8702
8703 return count;
8704}
8705
8706static const struct file_operations tracing_stats_fops = {
8707 .open = tracing_open_generic_tr,
8708 .read = tracing_stats_read,
8709 .llseek = generic_file_llseek,
8710 .release = tracing_release_generic_tr,
8711};
8712
8713#ifdef CONFIG_DYNAMIC_FTRACE
8714
8715static ssize_t
8716tracing_read_dyn_info(struct file *filp, char __user *ubuf,
8717 size_t cnt, loff_t *ppos)
8718{
8719 ssize_t ret;
8720 char *buf;
8721 int r;
8722
8723 /* 256 should be plenty to hold the amount needed */
8724 buf = kmalloc(256, GFP_KERNEL);
8725 if (!buf)
8726 return -ENOMEM;
8727
8728 r = scnprintf(buf, 256, "%ld pages:%ld groups: %ld\n",
8729 ftrace_update_tot_cnt,
8730 ftrace_number_of_pages,
8731 ftrace_number_of_groups);
8732
8733 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8734 kfree(buf);
8735 return ret;
8736}
8737
8738static const struct file_operations tracing_dyn_info_fops = {
8739 .open = tracing_open_generic,
8740 .read = tracing_read_dyn_info,
8741 .llseek = generic_file_llseek,
8742};
8743#endif /* CONFIG_DYNAMIC_FTRACE */
8744
8745#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
8746static void
8747ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
8748 struct trace_array *tr, struct ftrace_probe_ops *ops,
8749 void *data)
8750{
8751 tracing_snapshot_instance(tr);
8752}
8753
8754static void
8755ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
8756 struct trace_array *tr, struct ftrace_probe_ops *ops,
8757 void *data)
8758{
8759 struct ftrace_func_mapper *mapper = data;
8760 long *count = NULL;
8761
8762 if (mapper)
8763 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8764
8765 if (count) {
8766
8767 if (*count <= 0)
8768 return;
8769
8770 (*count)--;
8771 }
8772
8773 tracing_snapshot_instance(tr);
8774}
8775
8776static int
8777ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
8778 struct ftrace_probe_ops *ops, void *data)
8779{
8780 struct ftrace_func_mapper *mapper = data;
8781 long *count = NULL;
8782
8783 seq_printf(m, "%ps:", (void *)ip);
8784
8785 seq_puts(m, "snapshot");
8786
8787 if (mapper)
8788 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8789
8790 if (count)
8791 seq_printf(m, ":count=%ld\n", *count);
8792 else
8793 seq_puts(m, ":unlimited\n");
8794
8795 return 0;
8796}
8797
8798static int
8799ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
8800 unsigned long ip, void *init_data, void **data)
8801{
8802 struct ftrace_func_mapper *mapper = *data;
8803
8804 if (!mapper) {
8805 mapper = allocate_ftrace_func_mapper();
8806 if (!mapper)
8807 return -ENOMEM;
8808 *data = mapper;
8809 }
8810
8811 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
8812}
8813
8814static void
8815ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
8816 unsigned long ip, void *data)
8817{
8818 struct ftrace_func_mapper *mapper = data;
8819
8820 if (!ip) {
8821 if (!mapper)
8822 return;
8823 free_ftrace_func_mapper(mapper, NULL);
8824 return;
8825 }
8826
8827 ftrace_func_mapper_remove_ip(mapper, ip);
8828}
8829
8830static struct ftrace_probe_ops snapshot_probe_ops = {
8831 .func = ftrace_snapshot,
8832 .print = ftrace_snapshot_print,
8833};
8834
8835static struct ftrace_probe_ops snapshot_count_probe_ops = {
8836 .func = ftrace_count_snapshot,
8837 .print = ftrace_snapshot_print,
8838 .init = ftrace_snapshot_init,
8839 .free = ftrace_snapshot_free,
8840};
8841
8842static int
8843ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
8844 char *glob, char *cmd, char *param, int enable)
8845{
8846 struct ftrace_probe_ops *ops;
8847 void *count = (void *)-1;
8848 char *number;
8849 int ret;
8850
8851 if (!tr)
8852 return -ENODEV;
8853
8854 /* hash funcs only work with set_ftrace_filter */
8855 if (!enable)
8856 return -EINVAL;
8857
8858 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
8859
8860 if (glob[0] == '!')
8861 return unregister_ftrace_function_probe_func(glob+1, tr, ops);
8862
8863 if (!param)
8864 goto out_reg;
8865
8866 number = strsep(¶m, ":");
8867
8868 if (!strlen(number))
8869 goto out_reg;
8870
8871 /*
8872 * We use the callback data field (which is a pointer)
8873 * as our counter.
8874 */
8875 ret = kstrtoul(number, 0, (unsigned long *)&count);
8876 if (ret)
8877 return ret;
8878
8879 out_reg:
8880 ret = tracing_alloc_snapshot_instance(tr);
8881 if (ret < 0)
8882 goto out;
8883
8884 ret = register_ftrace_function_probe(glob, tr, ops, count);
8885
8886 out:
8887 return ret < 0 ? ret : 0;
8888}
8889
8890static struct ftrace_func_command ftrace_snapshot_cmd = {
8891 .name = "snapshot",
8892 .func = ftrace_trace_snapshot_callback,
8893};
8894
8895static __init int register_snapshot_cmd(void)
8896{
8897 return register_ftrace_command(&ftrace_snapshot_cmd);
8898}
8899#else
8900static inline __init int register_snapshot_cmd(void) { return 0; }
8901#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
8902
8903static struct dentry *tracing_get_dentry(struct trace_array *tr)
8904{
8905 if (WARN_ON(!tr->dir))
8906 return ERR_PTR(-ENODEV);
8907
8908 /* Top directory uses NULL as the parent */
8909 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
8910 return NULL;
8911
8912 /* All sub buffers have a descriptor */
8913 return tr->dir;
8914}
8915
8916static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
8917{
8918 struct dentry *d_tracer;
8919
8920 if (tr->percpu_dir)
8921 return tr->percpu_dir;
8922
8923 d_tracer = tracing_get_dentry(tr);
8924 if (IS_ERR(d_tracer))
8925 return NULL;
8926
8927 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
8928
8929 MEM_FAIL(!tr->percpu_dir,
8930 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
8931
8932 return tr->percpu_dir;
8933}
8934
8935static struct dentry *
8936trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
8937 void *data, long cpu, const struct file_operations *fops)
8938{
8939 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
8940
8941 if (ret) /* See tracing_get_cpu() */
8942 d_inode(ret)->i_cdev = (void *)(cpu + 1);
8943 return ret;
8944}
8945
8946static void
8947tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
8948{
8949 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
8950 struct dentry *d_cpu;
8951 char cpu_dir[30]; /* 30 characters should be more than enough */
8952
8953 if (!d_percpu)
8954 return;
8955
8956 snprintf(cpu_dir, 30, "cpu%ld", cpu);
8957 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
8958 if (!d_cpu) {
8959 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
8960 return;
8961 }
8962
8963 /* per cpu trace_pipe */
8964 trace_create_cpu_file("trace_pipe", TRACE_MODE_READ, d_cpu,
8965 tr, cpu, &tracing_pipe_fops);
8966
8967 /* per cpu trace */
8968 trace_create_cpu_file("trace", TRACE_MODE_WRITE, d_cpu,
8969 tr, cpu, &tracing_fops);
8970
8971 trace_create_cpu_file("trace_pipe_raw", TRACE_MODE_READ, d_cpu,
8972 tr, cpu, &tracing_buffers_fops);
8973
8974 trace_create_cpu_file("stats", TRACE_MODE_READ, d_cpu,
8975 tr, cpu, &tracing_stats_fops);
8976
8977 trace_create_cpu_file("buffer_size_kb", TRACE_MODE_READ, d_cpu,
8978 tr, cpu, &tracing_entries_fops);
8979
8980#ifdef CONFIG_TRACER_SNAPSHOT
8981 trace_create_cpu_file("snapshot", TRACE_MODE_WRITE, d_cpu,
8982 tr, cpu, &snapshot_fops);
8983
8984 trace_create_cpu_file("snapshot_raw", TRACE_MODE_READ, d_cpu,
8985 tr, cpu, &snapshot_raw_fops);
8986#endif
8987}
8988
8989#ifdef CONFIG_FTRACE_SELFTEST
8990/* Let selftest have access to static functions in this file */
8991#include "trace_selftest.c"
8992#endif
8993
8994static ssize_t
8995trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
8996 loff_t *ppos)
8997{
8998 struct trace_option_dentry *topt = filp->private_data;
8999 char *buf;
9000
9001 if (topt->flags->val & topt->opt->bit)
9002 buf = "1\n";
9003 else
9004 buf = "0\n";
9005
9006 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
9007}
9008
9009static ssize_t
9010trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
9011 loff_t *ppos)
9012{
9013 struct trace_option_dentry *topt = filp->private_data;
9014 unsigned long val;
9015 int ret;
9016
9017 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9018 if (ret)
9019 return ret;
9020
9021 if (val != 0 && val != 1)
9022 return -EINVAL;
9023
9024 if (!!(topt->flags->val & topt->opt->bit) != val) {
9025 mutex_lock(&trace_types_lock);
9026 ret = __set_tracer_option(topt->tr, topt->flags,
9027 topt->opt, !val);
9028 mutex_unlock(&trace_types_lock);
9029 if (ret)
9030 return ret;
9031 }
9032
9033 *ppos += cnt;
9034
9035 return cnt;
9036}
9037
9038static int tracing_open_options(struct inode *inode, struct file *filp)
9039{
9040 struct trace_option_dentry *topt = inode->i_private;
9041 int ret;
9042
9043 ret = tracing_check_open_get_tr(topt->tr);
9044 if (ret)
9045 return ret;
9046
9047 filp->private_data = inode->i_private;
9048 return 0;
9049}
9050
9051static int tracing_release_options(struct inode *inode, struct file *file)
9052{
9053 struct trace_option_dentry *topt = file->private_data;
9054
9055 trace_array_put(topt->tr);
9056 return 0;
9057}
9058
9059static const struct file_operations trace_options_fops = {
9060 .open = tracing_open_options,
9061 .read = trace_options_read,
9062 .write = trace_options_write,
9063 .llseek = generic_file_llseek,
9064 .release = tracing_release_options,
9065};
9066
9067/*
9068 * In order to pass in both the trace_array descriptor as well as the index
9069 * to the flag that the trace option file represents, the trace_array
9070 * has a character array of trace_flags_index[], which holds the index
9071 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
9072 * The address of this character array is passed to the flag option file
9073 * read/write callbacks.
9074 *
9075 * In order to extract both the index and the trace_array descriptor,
9076 * get_tr_index() uses the following algorithm.
9077 *
9078 * idx = *ptr;
9079 *
9080 * As the pointer itself contains the address of the index (remember
9081 * index[1] == 1).
9082 *
9083 * Then to get the trace_array descriptor, by subtracting that index
9084 * from the ptr, we get to the start of the index itself.
9085 *
9086 * ptr - idx == &index[0]
9087 *
9088 * Then a simple container_of() from that pointer gets us to the
9089 * trace_array descriptor.
9090 */
9091static void get_tr_index(void *data, struct trace_array **ptr,
9092 unsigned int *pindex)
9093{
9094 *pindex = *(unsigned char *)data;
9095
9096 *ptr = container_of(data - *pindex, struct trace_array,
9097 trace_flags_index);
9098}
9099
9100static ssize_t
9101trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
9102 loff_t *ppos)
9103{
9104 void *tr_index = filp->private_data;
9105 struct trace_array *tr;
9106 unsigned int index;
9107 char *buf;
9108
9109 get_tr_index(tr_index, &tr, &index);
9110
9111 if (tr->trace_flags & (1 << index))
9112 buf = "1\n";
9113 else
9114 buf = "0\n";
9115
9116 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
9117}
9118
9119static ssize_t
9120trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
9121 loff_t *ppos)
9122{
9123 void *tr_index = filp->private_data;
9124 struct trace_array *tr;
9125 unsigned int index;
9126 unsigned long val;
9127 int ret;
9128
9129 get_tr_index(tr_index, &tr, &index);
9130
9131 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9132 if (ret)
9133 return ret;
9134
9135 if (val != 0 && val != 1)
9136 return -EINVAL;
9137
9138 mutex_lock(&event_mutex);
9139 mutex_lock(&trace_types_lock);
9140 ret = set_tracer_flag(tr, 1 << index, val);
9141 mutex_unlock(&trace_types_lock);
9142 mutex_unlock(&event_mutex);
9143
9144 if (ret < 0)
9145 return ret;
9146
9147 *ppos += cnt;
9148
9149 return cnt;
9150}
9151
9152static const struct file_operations trace_options_core_fops = {
9153 .open = tracing_open_generic,
9154 .read = trace_options_core_read,
9155 .write = trace_options_core_write,
9156 .llseek = generic_file_llseek,
9157};
9158
9159struct dentry *trace_create_file(const char *name,
9160 umode_t mode,
9161 struct dentry *parent,
9162 void *data,
9163 const struct file_operations *fops)
9164{
9165 struct dentry *ret;
9166
9167 ret = tracefs_create_file(name, mode, parent, data, fops);
9168 if (!ret)
9169 pr_warn("Could not create tracefs '%s' entry\n", name);
9170
9171 return ret;
9172}
9173
9174
9175static struct dentry *trace_options_init_dentry(struct trace_array *tr)
9176{
9177 struct dentry *d_tracer;
9178
9179 if (tr->options)
9180 return tr->options;
9181
9182 d_tracer = tracing_get_dentry(tr);
9183 if (IS_ERR(d_tracer))
9184 return NULL;
9185
9186 tr->options = tracefs_create_dir("options", d_tracer);
9187 if (!tr->options) {
9188 pr_warn("Could not create tracefs directory 'options'\n");
9189 return NULL;
9190 }
9191
9192 return tr->options;
9193}
9194
9195static void
9196create_trace_option_file(struct trace_array *tr,
9197 struct trace_option_dentry *topt,
9198 struct tracer_flags *flags,
9199 struct tracer_opt *opt)
9200{
9201 struct dentry *t_options;
9202
9203 t_options = trace_options_init_dentry(tr);
9204 if (!t_options)
9205 return;
9206
9207 topt->flags = flags;
9208 topt->opt = opt;
9209 topt->tr = tr;
9210
9211 topt->entry = trace_create_file(opt->name, TRACE_MODE_WRITE,
9212 t_options, topt, &trace_options_fops);
9213
9214}
9215
9216static void
9217create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
9218{
9219 struct trace_option_dentry *topts;
9220 struct trace_options *tr_topts;
9221 struct tracer_flags *flags;
9222 struct tracer_opt *opts;
9223 int cnt;
9224 int i;
9225
9226 if (!tracer)
9227 return;
9228
9229 flags = tracer->flags;
9230
9231 if (!flags || !flags->opts)
9232 return;
9233
9234 /*
9235 * If this is an instance, only create flags for tracers
9236 * the instance may have.
9237 */
9238 if (!trace_ok_for_array(tracer, tr))
9239 return;
9240
9241 for (i = 0; i < tr->nr_topts; i++) {
9242 /* Make sure there's no duplicate flags. */
9243 if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
9244 return;
9245 }
9246
9247 opts = flags->opts;
9248
9249 for (cnt = 0; opts[cnt].name; cnt++)
9250 ;
9251
9252 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
9253 if (!topts)
9254 return;
9255
9256 tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
9257 GFP_KERNEL);
9258 if (!tr_topts) {
9259 kfree(topts);
9260 return;
9261 }
9262
9263 tr->topts = tr_topts;
9264 tr->topts[tr->nr_topts].tracer = tracer;
9265 tr->topts[tr->nr_topts].topts = topts;
9266 tr->nr_topts++;
9267
9268 for (cnt = 0; opts[cnt].name; cnt++) {
9269 create_trace_option_file(tr, &topts[cnt], flags,
9270 &opts[cnt]);
9271 MEM_FAIL(topts[cnt].entry == NULL,
9272 "Failed to create trace option: %s",
9273 opts[cnt].name);
9274 }
9275}
9276
9277static struct dentry *
9278create_trace_option_core_file(struct trace_array *tr,
9279 const char *option, long index)
9280{
9281 struct dentry *t_options;
9282
9283 t_options = trace_options_init_dentry(tr);
9284 if (!t_options)
9285 return NULL;
9286
9287 return trace_create_file(option, TRACE_MODE_WRITE, t_options,
9288 (void *)&tr->trace_flags_index[index],
9289 &trace_options_core_fops);
9290}
9291
9292static void create_trace_options_dir(struct trace_array *tr)
9293{
9294 struct dentry *t_options;
9295 bool top_level = tr == &global_trace;
9296 int i;
9297
9298 t_options = trace_options_init_dentry(tr);
9299 if (!t_options)
9300 return;
9301
9302 for (i = 0; trace_options[i]; i++) {
9303 if (top_level ||
9304 !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
9305 create_trace_option_core_file(tr, trace_options[i], i);
9306 }
9307}
9308
9309static ssize_t
9310rb_simple_read(struct file *filp, char __user *ubuf,
9311 size_t cnt, loff_t *ppos)
9312{
9313 struct trace_array *tr = filp->private_data;
9314 char buf[64];
9315 int r;
9316
9317 r = tracer_tracing_is_on(tr);
9318 r = sprintf(buf, "%d\n", r);
9319
9320 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9321}
9322
9323static ssize_t
9324rb_simple_write(struct file *filp, const char __user *ubuf,
9325 size_t cnt, loff_t *ppos)
9326{
9327 struct trace_array *tr = filp->private_data;
9328 struct trace_buffer *buffer = tr->array_buffer.buffer;
9329 unsigned long val;
9330 int ret;
9331
9332 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9333 if (ret)
9334 return ret;
9335
9336 if (buffer) {
9337 mutex_lock(&trace_types_lock);
9338 if (!!val == tracer_tracing_is_on(tr)) {
9339 val = 0; /* do nothing */
9340 } else if (val) {
9341 tracer_tracing_on(tr);
9342 if (tr->current_trace->start)
9343 tr->current_trace->start(tr);
9344 } else {
9345 tracer_tracing_off(tr);
9346 if (tr->current_trace->stop)
9347 tr->current_trace->stop(tr);
9348 /* Wake up any waiters */
9349 ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS);
9350 }
9351 mutex_unlock(&trace_types_lock);
9352 }
9353
9354 (*ppos)++;
9355
9356 return cnt;
9357}
9358
9359static const struct file_operations rb_simple_fops = {
9360 .open = tracing_open_generic_tr,
9361 .read = rb_simple_read,
9362 .write = rb_simple_write,
9363 .release = tracing_release_generic_tr,
9364 .llseek = default_llseek,
9365};
9366
9367static ssize_t
9368buffer_percent_read(struct file *filp, char __user *ubuf,
9369 size_t cnt, loff_t *ppos)
9370{
9371 struct trace_array *tr = filp->private_data;
9372 char buf[64];
9373 int r;
9374
9375 r = tr->buffer_percent;
9376 r = sprintf(buf, "%d\n", r);
9377
9378 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9379}
9380
9381static ssize_t
9382buffer_percent_write(struct file *filp, const char __user *ubuf,
9383 size_t cnt, loff_t *ppos)
9384{
9385 struct trace_array *tr = filp->private_data;
9386 unsigned long val;
9387 int ret;
9388
9389 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9390 if (ret)
9391 return ret;
9392
9393 if (val > 100)
9394 return -EINVAL;
9395
9396 tr->buffer_percent = val;
9397
9398 (*ppos)++;
9399
9400 return cnt;
9401}
9402
9403static const struct file_operations buffer_percent_fops = {
9404 .open = tracing_open_generic_tr,
9405 .read = buffer_percent_read,
9406 .write = buffer_percent_write,
9407 .release = tracing_release_generic_tr,
9408 .llseek = default_llseek,
9409};
9410
9411static ssize_t
9412buffer_subbuf_size_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
9413{
9414 struct trace_array *tr = filp->private_data;
9415 size_t size;
9416 char buf[64];
9417 int order;
9418 int r;
9419
9420 order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
9421 size = (PAGE_SIZE << order) / 1024;
9422
9423 r = sprintf(buf, "%zd\n", size);
9424
9425 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9426}
9427
9428static ssize_t
9429buffer_subbuf_size_write(struct file *filp, const char __user *ubuf,
9430 size_t cnt, loff_t *ppos)
9431{
9432 struct trace_array *tr = filp->private_data;
9433 unsigned long val;
9434 int old_order;
9435 int order;
9436 int pages;
9437 int ret;
9438
9439 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9440 if (ret)
9441 return ret;
9442
9443 val *= 1024; /* value passed in is in KB */
9444
9445 pages = DIV_ROUND_UP(val, PAGE_SIZE);
9446 order = fls(pages - 1);
9447
9448 /* limit between 1 and 128 system pages */
9449 if (order < 0 || order > 7)
9450 return -EINVAL;
9451
9452 /* Do not allow tracing while changing the order of the ring buffer */
9453 tracing_stop_tr(tr);
9454
9455 old_order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
9456 if (old_order == order)
9457 goto out;
9458
9459 ret = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, order);
9460 if (ret)
9461 goto out;
9462
9463#ifdef CONFIG_TRACER_MAX_TRACE
9464
9465 if (!tr->allocated_snapshot)
9466 goto out_max;
9467
9468 ret = ring_buffer_subbuf_order_set(tr->max_buffer.buffer, order);
9469 if (ret) {
9470 /* Put back the old order */
9471 cnt = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, old_order);
9472 if (WARN_ON_ONCE(cnt)) {
9473 /*
9474 * AARGH! We are left with different orders!
9475 * The max buffer is our "snapshot" buffer.
9476 * When a tracer needs a snapshot (one of the
9477 * latency tracers), it swaps the max buffer
9478 * with the saved snap shot. We succeeded to
9479 * update the order of the main buffer, but failed to
9480 * update the order of the max buffer. But when we tried
9481 * to reset the main buffer to the original size, we
9482 * failed there too. This is very unlikely to
9483 * happen, but if it does, warn and kill all
9484 * tracing.
9485 */
9486 tracing_disabled = 1;
9487 }
9488 goto out;
9489 }
9490 out_max:
9491#endif
9492 (*ppos)++;
9493 out:
9494 if (ret)
9495 cnt = ret;
9496 tracing_start_tr(tr);
9497 return cnt;
9498}
9499
9500static const struct file_operations buffer_subbuf_size_fops = {
9501 .open = tracing_open_generic_tr,
9502 .read = buffer_subbuf_size_read,
9503 .write = buffer_subbuf_size_write,
9504 .release = tracing_release_generic_tr,
9505 .llseek = default_llseek,
9506};
9507
9508static struct dentry *trace_instance_dir;
9509
9510static void
9511init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
9512
9513static int
9514allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size)
9515{
9516 enum ring_buffer_flags rb_flags;
9517
9518 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
9519
9520 buf->tr = tr;
9521
9522 buf->buffer = ring_buffer_alloc(size, rb_flags);
9523 if (!buf->buffer)
9524 return -ENOMEM;
9525
9526 buf->data = alloc_percpu(struct trace_array_cpu);
9527 if (!buf->data) {
9528 ring_buffer_free(buf->buffer);
9529 buf->buffer = NULL;
9530 return -ENOMEM;
9531 }
9532
9533 /* Allocate the first page for all buffers */
9534 set_buffer_entries(&tr->array_buffer,
9535 ring_buffer_size(tr->array_buffer.buffer, 0));
9536
9537 return 0;
9538}
9539
9540static void free_trace_buffer(struct array_buffer *buf)
9541{
9542 if (buf->buffer) {
9543 ring_buffer_free(buf->buffer);
9544 buf->buffer = NULL;
9545 free_percpu(buf->data);
9546 buf->data = NULL;
9547 }
9548}
9549
9550static int allocate_trace_buffers(struct trace_array *tr, int size)
9551{
9552 int ret;
9553
9554 ret = allocate_trace_buffer(tr, &tr->array_buffer, size);
9555 if (ret)
9556 return ret;
9557
9558#ifdef CONFIG_TRACER_MAX_TRACE
9559 ret = allocate_trace_buffer(tr, &tr->max_buffer,
9560 allocate_snapshot ? size : 1);
9561 if (MEM_FAIL(ret, "Failed to allocate trace buffer\n")) {
9562 free_trace_buffer(&tr->array_buffer);
9563 return -ENOMEM;
9564 }
9565 tr->allocated_snapshot = allocate_snapshot;
9566
9567 allocate_snapshot = false;
9568#endif
9569
9570 return 0;
9571}
9572
9573static void free_trace_buffers(struct trace_array *tr)
9574{
9575 if (!tr)
9576 return;
9577
9578 free_trace_buffer(&tr->array_buffer);
9579
9580#ifdef CONFIG_TRACER_MAX_TRACE
9581 free_trace_buffer(&tr->max_buffer);
9582#endif
9583}
9584
9585static void init_trace_flags_index(struct trace_array *tr)
9586{
9587 int i;
9588
9589 /* Used by the trace options files */
9590 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
9591 tr->trace_flags_index[i] = i;
9592}
9593
9594static void __update_tracer_options(struct trace_array *tr)
9595{
9596 struct tracer *t;
9597
9598 for (t = trace_types; t; t = t->next)
9599 add_tracer_options(tr, t);
9600}
9601
9602static void update_tracer_options(struct trace_array *tr)
9603{
9604 mutex_lock(&trace_types_lock);
9605 tracer_options_updated = true;
9606 __update_tracer_options(tr);
9607 mutex_unlock(&trace_types_lock);
9608}
9609
9610/* Must have trace_types_lock held */
9611struct trace_array *trace_array_find(const char *instance)
9612{
9613 struct trace_array *tr, *found = NULL;
9614
9615 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9616 if (tr->name && strcmp(tr->name, instance) == 0) {
9617 found = tr;
9618 break;
9619 }
9620 }
9621
9622 return found;
9623}
9624
9625struct trace_array *trace_array_find_get(const char *instance)
9626{
9627 struct trace_array *tr;
9628
9629 mutex_lock(&trace_types_lock);
9630 tr = trace_array_find(instance);
9631 if (tr)
9632 tr->ref++;
9633 mutex_unlock(&trace_types_lock);
9634
9635 return tr;
9636}
9637
9638static int trace_array_create_dir(struct trace_array *tr)
9639{
9640 int ret;
9641
9642 tr->dir = tracefs_create_dir(tr->name, trace_instance_dir);
9643 if (!tr->dir)
9644 return -EINVAL;
9645
9646 ret = event_trace_add_tracer(tr->dir, tr);
9647 if (ret) {
9648 tracefs_remove(tr->dir);
9649 return ret;
9650 }
9651
9652 init_tracer_tracefs(tr, tr->dir);
9653 __update_tracer_options(tr);
9654
9655 return ret;
9656}
9657
9658static struct trace_array *
9659trace_array_create_systems(const char *name, const char *systems)
9660{
9661 struct trace_array *tr;
9662 int ret;
9663
9664 ret = -ENOMEM;
9665 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
9666 if (!tr)
9667 return ERR_PTR(ret);
9668
9669 tr->name = kstrdup(name, GFP_KERNEL);
9670 if (!tr->name)
9671 goto out_free_tr;
9672
9673 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
9674 goto out_free_tr;
9675
9676 if (!zalloc_cpumask_var(&tr->pipe_cpumask, GFP_KERNEL))
9677 goto out_free_tr;
9678
9679 if (systems) {
9680 tr->system_names = kstrdup_const(systems, GFP_KERNEL);
9681 if (!tr->system_names)
9682 goto out_free_tr;
9683 }
9684
9685 tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
9686
9687 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
9688
9689 raw_spin_lock_init(&tr->start_lock);
9690
9691 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
9692
9693 tr->current_trace = &nop_trace;
9694
9695 INIT_LIST_HEAD(&tr->systems);
9696 INIT_LIST_HEAD(&tr->events);
9697 INIT_LIST_HEAD(&tr->hist_vars);
9698 INIT_LIST_HEAD(&tr->err_log);
9699
9700 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
9701 goto out_free_tr;
9702
9703 /* The ring buffer is defaultly expanded */
9704 trace_set_ring_buffer_expanded(tr);
9705
9706 if (ftrace_allocate_ftrace_ops(tr) < 0)
9707 goto out_free_tr;
9708
9709 ftrace_init_trace_array(tr);
9710
9711 init_trace_flags_index(tr);
9712
9713 if (trace_instance_dir) {
9714 ret = trace_array_create_dir(tr);
9715 if (ret)
9716 goto out_free_tr;
9717 } else
9718 __trace_early_add_events(tr);
9719
9720 list_add(&tr->list, &ftrace_trace_arrays);
9721
9722 tr->ref++;
9723
9724 return tr;
9725
9726 out_free_tr:
9727 ftrace_free_ftrace_ops(tr);
9728 free_trace_buffers(tr);
9729 free_cpumask_var(tr->pipe_cpumask);
9730 free_cpumask_var(tr->tracing_cpumask);
9731 kfree_const(tr->system_names);
9732 kfree(tr->name);
9733 kfree(tr);
9734
9735 return ERR_PTR(ret);
9736}
9737
9738static struct trace_array *trace_array_create(const char *name)
9739{
9740 return trace_array_create_systems(name, NULL);
9741}
9742
9743static int instance_mkdir(const char *name)
9744{
9745 struct trace_array *tr;
9746 int ret;
9747
9748 mutex_lock(&event_mutex);
9749 mutex_lock(&trace_types_lock);
9750
9751 ret = -EEXIST;
9752 if (trace_array_find(name))
9753 goto out_unlock;
9754
9755 tr = trace_array_create(name);
9756
9757 ret = PTR_ERR_OR_ZERO(tr);
9758
9759out_unlock:
9760 mutex_unlock(&trace_types_lock);
9761 mutex_unlock(&event_mutex);
9762 return ret;
9763}
9764
9765/**
9766 * trace_array_get_by_name - Create/Lookup a trace array, given its name.
9767 * @name: The name of the trace array to be looked up/created.
9768 * @systems: A list of systems to create event directories for (NULL for all)
9769 *
9770 * Returns pointer to trace array with given name.
9771 * NULL, if it cannot be created.
9772 *
9773 * NOTE: This function increments the reference counter associated with the
9774 * trace array returned. This makes sure it cannot be freed while in use.
9775 * Use trace_array_put() once the trace array is no longer needed.
9776 * If the trace_array is to be freed, trace_array_destroy() needs to
9777 * be called after the trace_array_put(), or simply let user space delete
9778 * it from the tracefs instances directory. But until the
9779 * trace_array_put() is called, user space can not delete it.
9780 *
9781 */
9782struct trace_array *trace_array_get_by_name(const char *name, const char *systems)
9783{
9784 struct trace_array *tr;
9785
9786 mutex_lock(&event_mutex);
9787 mutex_lock(&trace_types_lock);
9788
9789 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9790 if (tr->name && strcmp(tr->name, name) == 0)
9791 goto out_unlock;
9792 }
9793
9794 tr = trace_array_create_systems(name, systems);
9795
9796 if (IS_ERR(tr))
9797 tr = NULL;
9798out_unlock:
9799 if (tr)
9800 tr->ref++;
9801
9802 mutex_unlock(&trace_types_lock);
9803 mutex_unlock(&event_mutex);
9804 return tr;
9805}
9806EXPORT_SYMBOL_GPL(trace_array_get_by_name);
9807
9808static int __remove_instance(struct trace_array *tr)
9809{
9810 int i;
9811
9812 /* Reference counter for a newly created trace array = 1. */
9813 if (tr->ref > 1 || (tr->current_trace && tr->trace_ref))
9814 return -EBUSY;
9815
9816 list_del(&tr->list);
9817
9818 /* Disable all the flags that were enabled coming in */
9819 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
9820 if ((1 << i) & ZEROED_TRACE_FLAGS)
9821 set_tracer_flag(tr, 1 << i, 0);
9822 }
9823
9824 tracing_set_nop(tr);
9825 clear_ftrace_function_probes(tr);
9826 event_trace_del_tracer(tr);
9827 ftrace_clear_pids(tr);
9828 ftrace_destroy_function_files(tr);
9829 tracefs_remove(tr->dir);
9830 free_percpu(tr->last_func_repeats);
9831 free_trace_buffers(tr);
9832 clear_tracing_err_log(tr);
9833
9834 for (i = 0; i < tr->nr_topts; i++) {
9835 kfree(tr->topts[i].topts);
9836 }
9837 kfree(tr->topts);
9838
9839 free_cpumask_var(tr->pipe_cpumask);
9840 free_cpumask_var(tr->tracing_cpumask);
9841 kfree_const(tr->system_names);
9842 kfree(tr->name);
9843 kfree(tr);
9844
9845 return 0;
9846}
9847
9848int trace_array_destroy(struct trace_array *this_tr)
9849{
9850 struct trace_array *tr;
9851 int ret;
9852
9853 if (!this_tr)
9854 return -EINVAL;
9855
9856 mutex_lock(&event_mutex);
9857 mutex_lock(&trace_types_lock);
9858
9859 ret = -ENODEV;
9860
9861 /* Making sure trace array exists before destroying it. */
9862 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9863 if (tr == this_tr) {
9864 ret = __remove_instance(tr);
9865 break;
9866 }
9867 }
9868
9869 mutex_unlock(&trace_types_lock);
9870 mutex_unlock(&event_mutex);
9871
9872 return ret;
9873}
9874EXPORT_SYMBOL_GPL(trace_array_destroy);
9875
9876static int instance_rmdir(const char *name)
9877{
9878 struct trace_array *tr;
9879 int ret;
9880
9881 mutex_lock(&event_mutex);
9882 mutex_lock(&trace_types_lock);
9883
9884 ret = -ENODEV;
9885 tr = trace_array_find(name);
9886 if (tr)
9887 ret = __remove_instance(tr);
9888
9889 mutex_unlock(&trace_types_lock);
9890 mutex_unlock(&event_mutex);
9891
9892 return ret;
9893}
9894
9895static __init void create_trace_instances(struct dentry *d_tracer)
9896{
9897 struct trace_array *tr;
9898
9899 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
9900 instance_mkdir,
9901 instance_rmdir);
9902 if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))
9903 return;
9904
9905 mutex_lock(&event_mutex);
9906 mutex_lock(&trace_types_lock);
9907
9908 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9909 if (!tr->name)
9910 continue;
9911 if (MEM_FAIL(trace_array_create_dir(tr) < 0,
9912 "Failed to create instance directory\n"))
9913 break;
9914 }
9915
9916 mutex_unlock(&trace_types_lock);
9917 mutex_unlock(&event_mutex);
9918}
9919
9920static void
9921init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
9922{
9923 int cpu;
9924
9925 trace_create_file("available_tracers", TRACE_MODE_READ, d_tracer,
9926 tr, &show_traces_fops);
9927
9928 trace_create_file("current_tracer", TRACE_MODE_WRITE, d_tracer,
9929 tr, &set_tracer_fops);
9930
9931 trace_create_file("tracing_cpumask", TRACE_MODE_WRITE, d_tracer,
9932 tr, &tracing_cpumask_fops);
9933
9934 trace_create_file("trace_options", TRACE_MODE_WRITE, d_tracer,
9935 tr, &tracing_iter_fops);
9936
9937 trace_create_file("trace", TRACE_MODE_WRITE, d_tracer,
9938 tr, &tracing_fops);
9939
9940 trace_create_file("trace_pipe", TRACE_MODE_READ, d_tracer,
9941 tr, &tracing_pipe_fops);
9942
9943 trace_create_file("buffer_size_kb", TRACE_MODE_WRITE, d_tracer,
9944 tr, &tracing_entries_fops);
9945
9946 trace_create_file("buffer_total_size_kb", TRACE_MODE_READ, d_tracer,
9947 tr, &tracing_total_entries_fops);
9948
9949 trace_create_file("free_buffer", 0200, d_tracer,
9950 tr, &tracing_free_buffer_fops);
9951
9952 trace_create_file("trace_marker", 0220, d_tracer,
9953 tr, &tracing_mark_fops);
9954
9955 tr->trace_marker_file = __find_event_file(tr, "ftrace", "print");
9956
9957 trace_create_file("trace_marker_raw", 0220, d_tracer,
9958 tr, &tracing_mark_raw_fops);
9959
9960 trace_create_file("trace_clock", TRACE_MODE_WRITE, d_tracer, tr,
9961 &trace_clock_fops);
9962
9963 trace_create_file("tracing_on", TRACE_MODE_WRITE, d_tracer,
9964 tr, &rb_simple_fops);
9965
9966 trace_create_file("timestamp_mode", TRACE_MODE_READ, d_tracer, tr,
9967 &trace_time_stamp_mode_fops);
9968
9969 tr->buffer_percent = 50;
9970
9971 trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer,
9972 tr, &buffer_percent_fops);
9973
9974 trace_create_file("buffer_subbuf_size_kb", TRACE_MODE_WRITE, d_tracer,
9975 tr, &buffer_subbuf_size_fops);
9976
9977 create_trace_options_dir(tr);
9978
9979#ifdef CONFIG_TRACER_MAX_TRACE
9980 trace_create_maxlat_file(tr, d_tracer);
9981#endif
9982
9983 if (ftrace_create_function_files(tr, d_tracer))
9984 MEM_FAIL(1, "Could not allocate function filter files");
9985
9986#ifdef CONFIG_TRACER_SNAPSHOT
9987 trace_create_file("snapshot", TRACE_MODE_WRITE, d_tracer,
9988 tr, &snapshot_fops);
9989#endif
9990
9991 trace_create_file("error_log", TRACE_MODE_WRITE, d_tracer,
9992 tr, &tracing_err_log_fops);
9993
9994 for_each_tracing_cpu(cpu)
9995 tracing_init_tracefs_percpu(tr, cpu);
9996
9997 ftrace_init_tracefs(tr, d_tracer);
9998}
9999
10000static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
10001{
10002 struct vfsmount *mnt;
10003 struct file_system_type *type;
10004
10005 /*
10006 * To maintain backward compatibility for tools that mount
10007 * debugfs to get to the tracing facility, tracefs is automatically
10008 * mounted to the debugfs/tracing directory.
10009 */
10010 type = get_fs_type("tracefs");
10011 if (!type)
10012 return NULL;
10013 mnt = vfs_submount(mntpt, type, "tracefs", NULL);
10014 put_filesystem(type);
10015 if (IS_ERR(mnt))
10016 return NULL;
10017 mntget(mnt);
10018
10019 return mnt;
10020}
10021
10022/**
10023 * tracing_init_dentry - initialize top level trace array
10024 *
10025 * This is called when creating files or directories in the tracing
10026 * directory. It is called via fs_initcall() by any of the boot up code
10027 * and expects to return the dentry of the top level tracing directory.
10028 */
10029int tracing_init_dentry(void)
10030{
10031 struct trace_array *tr = &global_trace;
10032
10033 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10034 pr_warn("Tracing disabled due to lockdown\n");
10035 return -EPERM;
10036 }
10037
10038 /* The top level trace array uses NULL as parent */
10039 if (tr->dir)
10040 return 0;
10041
10042 if (WARN_ON(!tracefs_initialized()))
10043 return -ENODEV;
10044
10045 /*
10046 * As there may still be users that expect the tracing
10047 * files to exist in debugfs/tracing, we must automount
10048 * the tracefs file system there, so older tools still
10049 * work with the newer kernel.
10050 */
10051 tr->dir = debugfs_create_automount("tracing", NULL,
10052 trace_automount, NULL);
10053
10054 return 0;
10055}
10056
10057extern struct trace_eval_map *__start_ftrace_eval_maps[];
10058extern struct trace_eval_map *__stop_ftrace_eval_maps[];
10059
10060static struct workqueue_struct *eval_map_wq __initdata;
10061static struct work_struct eval_map_work __initdata;
10062static struct work_struct tracerfs_init_work __initdata;
10063
10064static void __init eval_map_work_func(struct work_struct *work)
10065{
10066 int len;
10067
10068 len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
10069 trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
10070}
10071
10072static int __init trace_eval_init(void)
10073{
10074 INIT_WORK(&eval_map_work, eval_map_work_func);
10075
10076 eval_map_wq = alloc_workqueue("eval_map_wq", WQ_UNBOUND, 0);
10077 if (!eval_map_wq) {
10078 pr_err("Unable to allocate eval_map_wq\n");
10079 /* Do work here */
10080 eval_map_work_func(&eval_map_work);
10081 return -ENOMEM;
10082 }
10083
10084 queue_work(eval_map_wq, &eval_map_work);
10085 return 0;
10086}
10087
10088subsys_initcall(trace_eval_init);
10089
10090static int __init trace_eval_sync(void)
10091{
10092 /* Make sure the eval map updates are finished */
10093 if (eval_map_wq)
10094 destroy_workqueue(eval_map_wq);
10095 return 0;
10096}
10097
10098late_initcall_sync(trace_eval_sync);
10099
10100
10101#ifdef CONFIG_MODULES
10102static void trace_module_add_evals(struct module *mod)
10103{
10104 if (!mod->num_trace_evals)
10105 return;
10106
10107 /*
10108 * Modules with bad taint do not have events created, do
10109 * not bother with enums either.
10110 */
10111 if (trace_module_has_bad_taint(mod))
10112 return;
10113
10114 trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
10115}
10116
10117#ifdef CONFIG_TRACE_EVAL_MAP_FILE
10118static void trace_module_remove_evals(struct module *mod)
10119{
10120 union trace_eval_map_item *map;
10121 union trace_eval_map_item **last = &trace_eval_maps;
10122
10123 if (!mod->num_trace_evals)
10124 return;
10125
10126 mutex_lock(&trace_eval_mutex);
10127
10128 map = trace_eval_maps;
10129
10130 while (map) {
10131 if (map->head.mod == mod)
10132 break;
10133 map = trace_eval_jmp_to_tail(map);
10134 last = &map->tail.next;
10135 map = map->tail.next;
10136 }
10137 if (!map)
10138 goto out;
10139
10140 *last = trace_eval_jmp_to_tail(map)->tail.next;
10141 kfree(map);
10142 out:
10143 mutex_unlock(&trace_eval_mutex);
10144}
10145#else
10146static inline void trace_module_remove_evals(struct module *mod) { }
10147#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
10148
10149static int trace_module_notify(struct notifier_block *self,
10150 unsigned long val, void *data)
10151{
10152 struct module *mod = data;
10153
10154 switch (val) {
10155 case MODULE_STATE_COMING:
10156 trace_module_add_evals(mod);
10157 break;
10158 case MODULE_STATE_GOING:
10159 trace_module_remove_evals(mod);
10160 break;
10161 }
10162
10163 return NOTIFY_OK;
10164}
10165
10166static struct notifier_block trace_module_nb = {
10167 .notifier_call = trace_module_notify,
10168 .priority = 0,
10169};
10170#endif /* CONFIG_MODULES */
10171
10172static __init void tracer_init_tracefs_work_func(struct work_struct *work)
10173{
10174
10175 event_trace_init();
10176
10177 init_tracer_tracefs(&global_trace, NULL);
10178 ftrace_init_tracefs_toplevel(&global_trace, NULL);
10179
10180 trace_create_file("tracing_thresh", TRACE_MODE_WRITE, NULL,
10181 &global_trace, &tracing_thresh_fops);
10182
10183 trace_create_file("README", TRACE_MODE_READ, NULL,
10184 NULL, &tracing_readme_fops);
10185
10186 trace_create_file("saved_cmdlines", TRACE_MODE_READ, NULL,
10187 NULL, &tracing_saved_cmdlines_fops);
10188
10189 trace_create_file("saved_cmdlines_size", TRACE_MODE_WRITE, NULL,
10190 NULL, &tracing_saved_cmdlines_size_fops);
10191
10192 trace_create_file("saved_tgids", TRACE_MODE_READ, NULL,
10193 NULL, &tracing_saved_tgids_fops);
10194
10195 trace_create_eval_file(NULL);
10196
10197#ifdef CONFIG_MODULES
10198 register_module_notifier(&trace_module_nb);
10199#endif
10200
10201#ifdef CONFIG_DYNAMIC_FTRACE
10202 trace_create_file("dyn_ftrace_total_info", TRACE_MODE_READ, NULL,
10203 NULL, &tracing_dyn_info_fops);
10204#endif
10205
10206 create_trace_instances(NULL);
10207
10208 update_tracer_options(&global_trace);
10209}
10210
10211static __init int tracer_init_tracefs(void)
10212{
10213 int ret;
10214
10215 trace_access_lock_init();
10216
10217 ret = tracing_init_dentry();
10218 if (ret)
10219 return 0;
10220
10221 if (eval_map_wq) {
10222 INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func);
10223 queue_work(eval_map_wq, &tracerfs_init_work);
10224 } else {
10225 tracer_init_tracefs_work_func(NULL);
10226 }
10227
10228 rv_init_interface();
10229
10230 return 0;
10231}
10232
10233fs_initcall(tracer_init_tracefs);
10234
10235static int trace_die_panic_handler(struct notifier_block *self,
10236 unsigned long ev, void *unused);
10237
10238static struct notifier_block trace_panic_notifier = {
10239 .notifier_call = trace_die_panic_handler,
10240 .priority = INT_MAX - 1,
10241};
10242
10243static struct notifier_block trace_die_notifier = {
10244 .notifier_call = trace_die_panic_handler,
10245 .priority = INT_MAX - 1,
10246};
10247
10248/*
10249 * The idea is to execute the following die/panic callback early, in order
10250 * to avoid showing irrelevant information in the trace (like other panic
10251 * notifier functions); we are the 2nd to run, after hung_task/rcu_stall
10252 * warnings get disabled (to prevent potential log flooding).
10253 */
10254static int trace_die_panic_handler(struct notifier_block *self,
10255 unsigned long ev, void *unused)
10256{
10257 if (!ftrace_dump_on_oops)
10258 return NOTIFY_DONE;
10259
10260 /* The die notifier requires DIE_OOPS to trigger */
10261 if (self == &trace_die_notifier && ev != DIE_OOPS)
10262 return NOTIFY_DONE;
10263
10264 ftrace_dump(ftrace_dump_on_oops);
10265
10266 return NOTIFY_DONE;
10267}
10268
10269/*
10270 * printk is set to max of 1024, we really don't need it that big.
10271 * Nothing should be printing 1000 characters anyway.
10272 */
10273#define TRACE_MAX_PRINT 1000
10274
10275/*
10276 * Define here KERN_TRACE so that we have one place to modify
10277 * it if we decide to change what log level the ftrace dump
10278 * should be at.
10279 */
10280#define KERN_TRACE KERN_EMERG
10281
10282void
10283trace_printk_seq(struct trace_seq *s)
10284{
10285 /* Probably should print a warning here. */
10286 if (s->seq.len >= TRACE_MAX_PRINT)
10287 s->seq.len = TRACE_MAX_PRINT;
10288
10289 /*
10290 * More paranoid code. Although the buffer size is set to
10291 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
10292 * an extra layer of protection.
10293 */
10294 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
10295 s->seq.len = s->seq.size - 1;
10296
10297 /* should be zero ended, but we are paranoid. */
10298 s->buffer[s->seq.len] = 0;
10299
10300 printk(KERN_TRACE "%s", s->buffer);
10301
10302 trace_seq_init(s);
10303}
10304
10305void trace_init_global_iter(struct trace_iterator *iter)
10306{
10307 iter->tr = &global_trace;
10308 iter->trace = iter->tr->current_trace;
10309 iter->cpu_file = RING_BUFFER_ALL_CPUS;
10310 iter->array_buffer = &global_trace.array_buffer;
10311
10312 if (iter->trace && iter->trace->open)
10313 iter->trace->open(iter);
10314
10315 /* Annotate start of buffers if we had overruns */
10316 if (ring_buffer_overruns(iter->array_buffer->buffer))
10317 iter->iter_flags |= TRACE_FILE_ANNOTATE;
10318
10319 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
10320 if (trace_clocks[iter->tr->clock_id].in_ns)
10321 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
10322
10323 /* Can not use kmalloc for iter.temp and iter.fmt */
10324 iter->temp = static_temp_buf;
10325 iter->temp_size = STATIC_TEMP_BUF_SIZE;
10326 iter->fmt = static_fmt_buf;
10327 iter->fmt_size = STATIC_FMT_BUF_SIZE;
10328}
10329
10330void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
10331{
10332 /* use static because iter can be a bit big for the stack */
10333 static struct trace_iterator iter;
10334 static atomic_t dump_running;
10335 struct trace_array *tr = &global_trace;
10336 unsigned int old_userobj;
10337 unsigned long flags;
10338 int cnt = 0, cpu;
10339
10340 /* Only allow one dump user at a time. */
10341 if (atomic_inc_return(&dump_running) != 1) {
10342 atomic_dec(&dump_running);
10343 return;
10344 }
10345
10346 /*
10347 * Always turn off tracing when we dump.
10348 * We don't need to show trace output of what happens
10349 * between multiple crashes.
10350 *
10351 * If the user does a sysrq-z, then they can re-enable
10352 * tracing with echo 1 > tracing_on.
10353 */
10354 tracing_off();
10355
10356 local_irq_save(flags);
10357
10358 /* Simulate the iterator */
10359 trace_init_global_iter(&iter);
10360
10361 for_each_tracing_cpu(cpu) {
10362 atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
10363 }
10364
10365 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
10366
10367 /* don't look at user memory in panic mode */
10368 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
10369
10370 switch (oops_dump_mode) {
10371 case DUMP_ALL:
10372 iter.cpu_file = RING_BUFFER_ALL_CPUS;
10373 break;
10374 case DUMP_ORIG:
10375 iter.cpu_file = raw_smp_processor_id();
10376 break;
10377 case DUMP_NONE:
10378 goto out_enable;
10379 default:
10380 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
10381 iter.cpu_file = RING_BUFFER_ALL_CPUS;
10382 }
10383
10384 printk(KERN_TRACE "Dumping ftrace buffer:\n");
10385
10386 /* Did function tracer already get disabled? */
10387 if (ftrace_is_dead()) {
10388 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
10389 printk("# MAY BE MISSING FUNCTION EVENTS\n");
10390 }
10391
10392 /*
10393 * We need to stop all tracing on all CPUS to read
10394 * the next buffer. This is a bit expensive, but is
10395 * not done often. We fill all what we can read,
10396 * and then release the locks again.
10397 */
10398
10399 while (!trace_empty(&iter)) {
10400
10401 if (!cnt)
10402 printk(KERN_TRACE "---------------------------------\n");
10403
10404 cnt++;
10405
10406 trace_iterator_reset(&iter);
10407 iter.iter_flags |= TRACE_FILE_LAT_FMT;
10408
10409 if (trace_find_next_entry_inc(&iter) != NULL) {
10410 int ret;
10411
10412 ret = print_trace_line(&iter);
10413 if (ret != TRACE_TYPE_NO_CONSUME)
10414 trace_consume(&iter);
10415 }
10416 touch_nmi_watchdog();
10417
10418 trace_printk_seq(&iter.seq);
10419 }
10420
10421 if (!cnt)
10422 printk(KERN_TRACE " (ftrace buffer empty)\n");
10423 else
10424 printk(KERN_TRACE "---------------------------------\n");
10425
10426 out_enable:
10427 tr->trace_flags |= old_userobj;
10428
10429 for_each_tracing_cpu(cpu) {
10430 atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
10431 }
10432 atomic_dec(&dump_running);
10433 local_irq_restore(flags);
10434}
10435EXPORT_SYMBOL_GPL(ftrace_dump);
10436
10437#define WRITE_BUFSIZE 4096
10438
10439ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
10440 size_t count, loff_t *ppos,
10441 int (*createfn)(const char *))
10442{
10443 char *kbuf, *buf, *tmp;
10444 int ret = 0;
10445 size_t done = 0;
10446 size_t size;
10447
10448 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
10449 if (!kbuf)
10450 return -ENOMEM;
10451
10452 while (done < count) {
10453 size = count - done;
10454
10455 if (size >= WRITE_BUFSIZE)
10456 size = WRITE_BUFSIZE - 1;
10457
10458 if (copy_from_user(kbuf, buffer + done, size)) {
10459 ret = -EFAULT;
10460 goto out;
10461 }
10462 kbuf[size] = '\0';
10463 buf = kbuf;
10464 do {
10465 tmp = strchr(buf, '\n');
10466 if (tmp) {
10467 *tmp = '\0';
10468 size = tmp - buf + 1;
10469 } else {
10470 size = strlen(buf);
10471 if (done + size < count) {
10472 if (buf != kbuf)
10473 break;
10474 /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
10475 pr_warn("Line length is too long: Should be less than %d\n",
10476 WRITE_BUFSIZE - 2);
10477 ret = -EINVAL;
10478 goto out;
10479 }
10480 }
10481 done += size;
10482
10483 /* Remove comments */
10484 tmp = strchr(buf, '#');
10485
10486 if (tmp)
10487 *tmp = '\0';
10488
10489 ret = createfn(buf);
10490 if (ret)
10491 goto out;
10492 buf += size;
10493
10494 } while (done < count);
10495 }
10496 ret = done;
10497
10498out:
10499 kfree(kbuf);
10500
10501 return ret;
10502}
10503
10504#ifdef CONFIG_TRACER_MAX_TRACE
10505__init static bool tr_needs_alloc_snapshot(const char *name)
10506{
10507 char *test;
10508 int len = strlen(name);
10509 bool ret;
10510
10511 if (!boot_snapshot_index)
10512 return false;
10513
10514 if (strncmp(name, boot_snapshot_info, len) == 0 &&
10515 boot_snapshot_info[len] == '\t')
10516 return true;
10517
10518 test = kmalloc(strlen(name) + 3, GFP_KERNEL);
10519 if (!test)
10520 return false;
10521
10522 sprintf(test, "\t%s\t", name);
10523 ret = strstr(boot_snapshot_info, test) == NULL;
10524 kfree(test);
10525 return ret;
10526}
10527
10528__init static void do_allocate_snapshot(const char *name)
10529{
10530 if (!tr_needs_alloc_snapshot(name))
10531 return;
10532
10533 /*
10534 * When allocate_snapshot is set, the next call to
10535 * allocate_trace_buffers() (called by trace_array_get_by_name())
10536 * will allocate the snapshot buffer. That will alse clear
10537 * this flag.
10538 */
10539 allocate_snapshot = true;
10540}
10541#else
10542static inline void do_allocate_snapshot(const char *name) { }
10543#endif
10544
10545__init static void enable_instances(void)
10546{
10547 struct trace_array *tr;
10548 char *curr_str;
10549 char *str;
10550 char *tok;
10551
10552 /* A tab is always appended */
10553 boot_instance_info[boot_instance_index - 1] = '\0';
10554 str = boot_instance_info;
10555
10556 while ((curr_str = strsep(&str, "\t"))) {
10557
10558 tok = strsep(&curr_str, ",");
10559
10560 if (IS_ENABLED(CONFIG_TRACER_MAX_TRACE))
10561 do_allocate_snapshot(tok);
10562
10563 tr = trace_array_get_by_name(tok, NULL);
10564 if (!tr) {
10565 pr_warn("Failed to create instance buffer %s\n", curr_str);
10566 continue;
10567 }
10568 /* Allow user space to delete it */
10569 trace_array_put(tr);
10570
10571 while ((tok = strsep(&curr_str, ","))) {
10572 early_enable_events(tr, tok, true);
10573 }
10574 }
10575}
10576
10577__init static int tracer_alloc_buffers(void)
10578{
10579 int ring_buf_size;
10580 int ret = -ENOMEM;
10581
10582
10583 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10584 pr_warn("Tracing disabled due to lockdown\n");
10585 return -EPERM;
10586 }
10587
10588 /*
10589 * Make sure we don't accidentally add more trace options
10590 * than we have bits for.
10591 */
10592 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
10593
10594 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
10595 goto out;
10596
10597 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
10598 goto out_free_buffer_mask;
10599
10600 /* Only allocate trace_printk buffers if a trace_printk exists */
10601 if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
10602 /* Must be called before global_trace.buffer is allocated */
10603 trace_printk_init_buffers();
10604
10605 /* To save memory, keep the ring buffer size to its minimum */
10606 if (global_trace.ring_buffer_expanded)
10607 ring_buf_size = trace_buf_size;
10608 else
10609 ring_buf_size = 1;
10610
10611 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
10612 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
10613
10614 raw_spin_lock_init(&global_trace.start_lock);
10615
10616 /*
10617 * The prepare callbacks allocates some memory for the ring buffer. We
10618 * don't free the buffer if the CPU goes down. If we were to free
10619 * the buffer, then the user would lose any trace that was in the
10620 * buffer. The memory will be removed once the "instance" is removed.
10621 */
10622 ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
10623 "trace/RB:prepare", trace_rb_cpu_prepare,
10624 NULL);
10625 if (ret < 0)
10626 goto out_free_cpumask;
10627 /* Used for event triggers */
10628 ret = -ENOMEM;
10629 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
10630 if (!temp_buffer)
10631 goto out_rm_hp_state;
10632
10633 if (trace_create_savedcmd() < 0)
10634 goto out_free_temp_buffer;
10635
10636 if (!zalloc_cpumask_var(&global_trace.pipe_cpumask, GFP_KERNEL))
10637 goto out_free_savedcmd;
10638
10639 /* TODO: make the number of buffers hot pluggable with CPUS */
10640 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
10641 MEM_FAIL(1, "tracer: failed to allocate ring buffer!\n");
10642 goto out_free_pipe_cpumask;
10643 }
10644 if (global_trace.buffer_disabled)
10645 tracing_off();
10646
10647 if (trace_boot_clock) {
10648 ret = tracing_set_clock(&global_trace, trace_boot_clock);
10649 if (ret < 0)
10650 pr_warn("Trace clock %s not defined, going back to default\n",
10651 trace_boot_clock);
10652 }
10653
10654 /*
10655 * register_tracer() might reference current_trace, so it
10656 * needs to be set before we register anything. This is
10657 * just a bootstrap of current_trace anyway.
10658 */
10659 global_trace.current_trace = &nop_trace;
10660
10661 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
10662
10663 ftrace_init_global_array_ops(&global_trace);
10664
10665 init_trace_flags_index(&global_trace);
10666
10667 register_tracer(&nop_trace);
10668
10669 /* Function tracing may start here (via kernel command line) */
10670 init_function_trace();
10671
10672 /* All seems OK, enable tracing */
10673 tracing_disabled = 0;
10674
10675 atomic_notifier_chain_register(&panic_notifier_list,
10676 &trace_panic_notifier);
10677
10678 register_die_notifier(&trace_die_notifier);
10679
10680 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
10681
10682 INIT_LIST_HEAD(&global_trace.systems);
10683 INIT_LIST_HEAD(&global_trace.events);
10684 INIT_LIST_HEAD(&global_trace.hist_vars);
10685 INIT_LIST_HEAD(&global_trace.err_log);
10686 list_add(&global_trace.list, &ftrace_trace_arrays);
10687
10688 apply_trace_boot_options();
10689
10690 register_snapshot_cmd();
10691
10692 test_can_verify();
10693
10694 return 0;
10695
10696out_free_pipe_cpumask:
10697 free_cpumask_var(global_trace.pipe_cpumask);
10698out_free_savedcmd:
10699 free_saved_cmdlines_buffer(savedcmd);
10700out_free_temp_buffer:
10701 ring_buffer_free(temp_buffer);
10702out_rm_hp_state:
10703 cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
10704out_free_cpumask:
10705 free_cpumask_var(global_trace.tracing_cpumask);
10706out_free_buffer_mask:
10707 free_cpumask_var(tracing_buffer_mask);
10708out:
10709 return ret;
10710}
10711
10712void __init ftrace_boot_snapshot(void)
10713{
10714#ifdef CONFIG_TRACER_MAX_TRACE
10715 struct trace_array *tr;
10716
10717 if (!snapshot_at_boot)
10718 return;
10719
10720 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
10721 if (!tr->allocated_snapshot)
10722 continue;
10723
10724 tracing_snapshot_instance(tr);
10725 trace_array_puts(tr, "** Boot snapshot taken **\n");
10726 }
10727#endif
10728}
10729
10730void __init early_trace_init(void)
10731{
10732 if (tracepoint_printk) {
10733 tracepoint_print_iter =
10734 kzalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
10735 if (MEM_FAIL(!tracepoint_print_iter,
10736 "Failed to allocate trace iterator\n"))
10737 tracepoint_printk = 0;
10738 else
10739 static_key_enable(&tracepoint_printk_key.key);
10740 }
10741 tracer_alloc_buffers();
10742
10743 init_events();
10744}
10745
10746void __init trace_init(void)
10747{
10748 trace_event_init();
10749
10750 if (boot_instance_index)
10751 enable_instances();
10752}
10753
10754__init static void clear_boot_tracer(void)
10755{
10756 /*
10757 * The default tracer at boot buffer is an init section.
10758 * This function is called in lateinit. If we did not
10759 * find the boot tracer, then clear it out, to prevent
10760 * later registration from accessing the buffer that is
10761 * about to be freed.
10762 */
10763 if (!default_bootup_tracer)
10764 return;
10765
10766 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
10767 default_bootup_tracer);
10768 default_bootup_tracer = NULL;
10769}
10770
10771#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
10772__init static void tracing_set_default_clock(void)
10773{
10774 /* sched_clock_stable() is determined in late_initcall */
10775 if (!trace_boot_clock && !sched_clock_stable()) {
10776 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10777 pr_warn("Can not set tracing clock due to lockdown\n");
10778 return;
10779 }
10780
10781 printk(KERN_WARNING
10782 "Unstable clock detected, switching default tracing clock to \"global\"\n"
10783 "If you want to keep using the local clock, then add:\n"
10784 " \"trace_clock=local\"\n"
10785 "on the kernel command line\n");
10786 tracing_set_clock(&global_trace, "global");
10787 }
10788}
10789#else
10790static inline void tracing_set_default_clock(void) { }
10791#endif
10792
10793__init static int late_trace_init(void)
10794{
10795 if (tracepoint_printk && tracepoint_printk_stop_on_boot) {
10796 static_key_disable(&tracepoint_printk_key.key);
10797 tracepoint_printk = 0;
10798 }
10799
10800 tracing_set_default_clock();
10801 clear_boot_tracer();
10802 return 0;
10803}
10804
10805late_initcall_sync(late_trace_init);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ring buffer based function tracer
4 *
5 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Originally taken from the RT patch by:
9 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 *
11 * Based on code from the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 Nadia Yvette Chambers
14 */
15#include <linux/ring_buffer.h>
16#include <generated/utsrelease.h>
17#include <linux/stacktrace.h>
18#include <linux/writeback.h>
19#include <linux/kallsyms.h>
20#include <linux/security.h>
21#include <linux/seq_file.h>
22#include <linux/notifier.h>
23#include <linux/irqflags.h>
24#include <linux/debugfs.h>
25#include <linux/tracefs.h>
26#include <linux/pagemap.h>
27#include <linux/hardirq.h>
28#include <linux/linkage.h>
29#include <linux/uaccess.h>
30#include <linux/vmalloc.h>
31#include <linux/ftrace.h>
32#include <linux/module.h>
33#include <linux/percpu.h>
34#include <linux/splice.h>
35#include <linux/kdebug.h>
36#include <linux/string.h>
37#include <linux/mount.h>
38#include <linux/rwsem.h>
39#include <linux/slab.h>
40#include <linux/ctype.h>
41#include <linux/init.h>
42#include <linux/poll.h>
43#include <linux/nmi.h>
44#include <linux/fs.h>
45#include <linux/trace.h>
46#include <linux/sched/clock.h>
47#include <linux/sched/rt.h>
48
49#include "trace.h"
50#include "trace_output.h"
51
52/*
53 * On boot up, the ring buffer is set to the minimum size, so that
54 * we do not waste memory on systems that are not using tracing.
55 */
56bool ring_buffer_expanded;
57
58/*
59 * We need to change this state when a selftest is running.
60 * A selftest will lurk into the ring-buffer to count the
61 * entries inserted during the selftest although some concurrent
62 * insertions into the ring-buffer such as trace_printk could occurred
63 * at the same time, giving false positive or negative results.
64 */
65static bool __read_mostly tracing_selftest_running;
66
67/*
68 * If a tracer is running, we do not want to run SELFTEST.
69 */
70bool __read_mostly tracing_selftest_disabled;
71
72/* Pipe tracepoints to printk */
73struct trace_iterator *tracepoint_print_iter;
74int tracepoint_printk;
75static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
76
77/* For tracers that don't implement custom flags */
78static struct tracer_opt dummy_tracer_opt[] = {
79 { }
80};
81
82static int
83dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
84{
85 return 0;
86}
87
88/*
89 * To prevent the comm cache from being overwritten when no
90 * tracing is active, only save the comm when a trace event
91 * occurred.
92 */
93static DEFINE_PER_CPU(bool, trace_taskinfo_save);
94
95/*
96 * Kill all tracing for good (never come back).
97 * It is initialized to 1 but will turn to zero if the initialization
98 * of the tracer is successful. But that is the only place that sets
99 * this back to zero.
100 */
101static int tracing_disabled = 1;
102
103cpumask_var_t __read_mostly tracing_buffer_mask;
104
105/*
106 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
107 *
108 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
109 * is set, then ftrace_dump is called. This will output the contents
110 * of the ftrace buffers to the console. This is very useful for
111 * capturing traces that lead to crashes and outputing it to a
112 * serial console.
113 *
114 * It is default off, but you can enable it with either specifying
115 * "ftrace_dump_on_oops" in the kernel command line, or setting
116 * /proc/sys/kernel/ftrace_dump_on_oops
117 * Set 1 if you want to dump buffers of all CPUs
118 * Set 2 if you want to dump the buffer of the CPU that triggered oops
119 */
120
121enum ftrace_dump_mode ftrace_dump_on_oops;
122
123/* When set, tracing will stop when a WARN*() is hit */
124int __disable_trace_on_warning;
125
126#ifdef CONFIG_TRACE_EVAL_MAP_FILE
127/* Map of enums to their values, for "eval_map" file */
128struct trace_eval_map_head {
129 struct module *mod;
130 unsigned long length;
131};
132
133union trace_eval_map_item;
134
135struct trace_eval_map_tail {
136 /*
137 * "end" is first and points to NULL as it must be different
138 * than "mod" or "eval_string"
139 */
140 union trace_eval_map_item *next;
141 const char *end; /* points to NULL */
142};
143
144static DEFINE_MUTEX(trace_eval_mutex);
145
146/*
147 * The trace_eval_maps are saved in an array with two extra elements,
148 * one at the beginning, and one at the end. The beginning item contains
149 * the count of the saved maps (head.length), and the module they
150 * belong to if not built in (head.mod). The ending item contains a
151 * pointer to the next array of saved eval_map items.
152 */
153union trace_eval_map_item {
154 struct trace_eval_map map;
155 struct trace_eval_map_head head;
156 struct trace_eval_map_tail tail;
157};
158
159static union trace_eval_map_item *trace_eval_maps;
160#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
161
162static int tracing_set_tracer(struct trace_array *tr, const char *buf);
163static void ftrace_trace_userstack(struct ring_buffer *buffer,
164 unsigned long flags, int pc);
165
166#define MAX_TRACER_SIZE 100
167static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
168static char *default_bootup_tracer;
169
170static bool allocate_snapshot;
171
172static int __init set_cmdline_ftrace(char *str)
173{
174 strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
175 default_bootup_tracer = bootup_tracer_buf;
176 /* We are using ftrace early, expand it */
177 ring_buffer_expanded = true;
178 return 1;
179}
180__setup("ftrace=", set_cmdline_ftrace);
181
182static int __init set_ftrace_dump_on_oops(char *str)
183{
184 if (*str++ != '=' || !*str) {
185 ftrace_dump_on_oops = DUMP_ALL;
186 return 1;
187 }
188
189 if (!strcmp("orig_cpu", str)) {
190 ftrace_dump_on_oops = DUMP_ORIG;
191 return 1;
192 }
193
194 return 0;
195}
196__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
197
198static int __init stop_trace_on_warning(char *str)
199{
200 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
201 __disable_trace_on_warning = 1;
202 return 1;
203}
204__setup("traceoff_on_warning", stop_trace_on_warning);
205
206static int __init boot_alloc_snapshot(char *str)
207{
208 allocate_snapshot = true;
209 /* We also need the main ring buffer expanded */
210 ring_buffer_expanded = true;
211 return 1;
212}
213__setup("alloc_snapshot", boot_alloc_snapshot);
214
215
216static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
217
218static int __init set_trace_boot_options(char *str)
219{
220 strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
221 return 0;
222}
223__setup("trace_options=", set_trace_boot_options);
224
225static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
226static char *trace_boot_clock __initdata;
227
228static int __init set_trace_boot_clock(char *str)
229{
230 strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
231 trace_boot_clock = trace_boot_clock_buf;
232 return 0;
233}
234__setup("trace_clock=", set_trace_boot_clock);
235
236static int __init set_tracepoint_printk(char *str)
237{
238 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
239 tracepoint_printk = 1;
240 return 1;
241}
242__setup("tp_printk", set_tracepoint_printk);
243
244unsigned long long ns2usecs(u64 nsec)
245{
246 nsec += 500;
247 do_div(nsec, 1000);
248 return nsec;
249}
250
251/* trace_flags holds trace_options default values */
252#define TRACE_DEFAULT_FLAGS \
253 (FUNCTION_DEFAULT_FLAGS | \
254 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
255 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
256 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
257 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS)
258
259/* trace_options that are only supported by global_trace */
260#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
261 TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
262
263/* trace_flags that are default zero for instances */
264#define ZEROED_TRACE_FLAGS \
265 (TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK)
266
267/*
268 * The global_trace is the descriptor that holds the top-level tracing
269 * buffers for the live tracing.
270 */
271static struct trace_array global_trace = {
272 .trace_flags = TRACE_DEFAULT_FLAGS,
273};
274
275LIST_HEAD(ftrace_trace_arrays);
276
277int trace_array_get(struct trace_array *this_tr)
278{
279 struct trace_array *tr;
280 int ret = -ENODEV;
281
282 mutex_lock(&trace_types_lock);
283 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
284 if (tr == this_tr) {
285 tr->ref++;
286 ret = 0;
287 break;
288 }
289 }
290 mutex_unlock(&trace_types_lock);
291
292 return ret;
293}
294
295static void __trace_array_put(struct trace_array *this_tr)
296{
297 WARN_ON(!this_tr->ref);
298 this_tr->ref--;
299}
300
301void trace_array_put(struct trace_array *this_tr)
302{
303 mutex_lock(&trace_types_lock);
304 __trace_array_put(this_tr);
305 mutex_unlock(&trace_types_lock);
306}
307
308int tracing_check_open_get_tr(struct trace_array *tr)
309{
310 int ret;
311
312 ret = security_locked_down(LOCKDOWN_TRACEFS);
313 if (ret)
314 return ret;
315
316 if (tracing_disabled)
317 return -ENODEV;
318
319 if (tr && trace_array_get(tr) < 0)
320 return -ENODEV;
321
322 return 0;
323}
324
325int call_filter_check_discard(struct trace_event_call *call, void *rec,
326 struct ring_buffer *buffer,
327 struct ring_buffer_event *event)
328{
329 if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
330 !filter_match_preds(call->filter, rec)) {
331 __trace_event_discard_commit(buffer, event);
332 return 1;
333 }
334
335 return 0;
336}
337
338void trace_free_pid_list(struct trace_pid_list *pid_list)
339{
340 vfree(pid_list->pids);
341 kfree(pid_list);
342}
343
344/**
345 * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
346 * @filtered_pids: The list of pids to check
347 * @search_pid: The PID to find in @filtered_pids
348 *
349 * Returns true if @search_pid is fonud in @filtered_pids, and false otherwis.
350 */
351bool
352trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
353{
354 /*
355 * If pid_max changed after filtered_pids was created, we
356 * by default ignore all pids greater than the previous pid_max.
357 */
358 if (search_pid >= filtered_pids->pid_max)
359 return false;
360
361 return test_bit(search_pid, filtered_pids->pids);
362}
363
364/**
365 * trace_ignore_this_task - should a task be ignored for tracing
366 * @filtered_pids: The list of pids to check
367 * @task: The task that should be ignored if not filtered
368 *
369 * Checks if @task should be traced or not from @filtered_pids.
370 * Returns true if @task should *NOT* be traced.
371 * Returns false if @task should be traced.
372 */
373bool
374trace_ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct *task)
375{
376 /*
377 * Return false, because if filtered_pids does not exist,
378 * all pids are good to trace.
379 */
380 if (!filtered_pids)
381 return false;
382
383 return !trace_find_filtered_pid(filtered_pids, task->pid);
384}
385
386/**
387 * trace_filter_add_remove_task - Add or remove a task from a pid_list
388 * @pid_list: The list to modify
389 * @self: The current task for fork or NULL for exit
390 * @task: The task to add or remove
391 *
392 * If adding a task, if @self is defined, the task is only added if @self
393 * is also included in @pid_list. This happens on fork and tasks should
394 * only be added when the parent is listed. If @self is NULL, then the
395 * @task pid will be removed from the list, which would happen on exit
396 * of a task.
397 */
398void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
399 struct task_struct *self,
400 struct task_struct *task)
401{
402 if (!pid_list)
403 return;
404
405 /* For forks, we only add if the forking task is listed */
406 if (self) {
407 if (!trace_find_filtered_pid(pid_list, self->pid))
408 return;
409 }
410
411 /* Sorry, but we don't support pid_max changing after setting */
412 if (task->pid >= pid_list->pid_max)
413 return;
414
415 /* "self" is set for forks, and NULL for exits */
416 if (self)
417 set_bit(task->pid, pid_list->pids);
418 else
419 clear_bit(task->pid, pid_list->pids);
420}
421
422/**
423 * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
424 * @pid_list: The pid list to show
425 * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
426 * @pos: The position of the file
427 *
428 * This is used by the seq_file "next" operation to iterate the pids
429 * listed in a trace_pid_list structure.
430 *
431 * Returns the pid+1 as we want to display pid of zero, but NULL would
432 * stop the iteration.
433 */
434void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
435{
436 unsigned long pid = (unsigned long)v;
437
438 (*pos)++;
439
440 /* pid already is +1 of the actual prevous bit */
441 pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
442
443 /* Return pid + 1 to allow zero to be represented */
444 if (pid < pid_list->pid_max)
445 return (void *)(pid + 1);
446
447 return NULL;
448}
449
450/**
451 * trace_pid_start - Used for seq_file to start reading pid lists
452 * @pid_list: The pid list to show
453 * @pos: The position of the file
454 *
455 * This is used by seq_file "start" operation to start the iteration
456 * of listing pids.
457 *
458 * Returns the pid+1 as we want to display pid of zero, but NULL would
459 * stop the iteration.
460 */
461void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
462{
463 unsigned long pid;
464 loff_t l = 0;
465
466 pid = find_first_bit(pid_list->pids, pid_list->pid_max);
467 if (pid >= pid_list->pid_max)
468 return NULL;
469
470 /* Return pid + 1 so that zero can be the exit value */
471 for (pid++; pid && l < *pos;
472 pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
473 ;
474 return (void *)pid;
475}
476
477/**
478 * trace_pid_show - show the current pid in seq_file processing
479 * @m: The seq_file structure to write into
480 * @v: A void pointer of the pid (+1) value to display
481 *
482 * Can be directly used by seq_file operations to display the current
483 * pid value.
484 */
485int trace_pid_show(struct seq_file *m, void *v)
486{
487 unsigned long pid = (unsigned long)v - 1;
488
489 seq_printf(m, "%lu\n", pid);
490 return 0;
491}
492
493/* 128 should be much more than enough */
494#define PID_BUF_SIZE 127
495
496int trace_pid_write(struct trace_pid_list *filtered_pids,
497 struct trace_pid_list **new_pid_list,
498 const char __user *ubuf, size_t cnt)
499{
500 struct trace_pid_list *pid_list;
501 struct trace_parser parser;
502 unsigned long val;
503 int nr_pids = 0;
504 ssize_t read = 0;
505 ssize_t ret = 0;
506 loff_t pos;
507 pid_t pid;
508
509 if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
510 return -ENOMEM;
511
512 /*
513 * Always recreate a new array. The write is an all or nothing
514 * operation. Always create a new array when adding new pids by
515 * the user. If the operation fails, then the current list is
516 * not modified.
517 */
518 pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
519 if (!pid_list) {
520 trace_parser_put(&parser);
521 return -ENOMEM;
522 }
523
524 pid_list->pid_max = READ_ONCE(pid_max);
525
526 /* Only truncating will shrink pid_max */
527 if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max)
528 pid_list->pid_max = filtered_pids->pid_max;
529
530 pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
531 if (!pid_list->pids) {
532 trace_parser_put(&parser);
533 kfree(pid_list);
534 return -ENOMEM;
535 }
536
537 if (filtered_pids) {
538 /* copy the current bits to the new max */
539 for_each_set_bit(pid, filtered_pids->pids,
540 filtered_pids->pid_max) {
541 set_bit(pid, pid_list->pids);
542 nr_pids++;
543 }
544 }
545
546 while (cnt > 0) {
547
548 pos = 0;
549
550 ret = trace_get_user(&parser, ubuf, cnt, &pos);
551 if (ret < 0 || !trace_parser_loaded(&parser))
552 break;
553
554 read += ret;
555 ubuf += ret;
556 cnt -= ret;
557
558 ret = -EINVAL;
559 if (kstrtoul(parser.buffer, 0, &val))
560 break;
561 if (val >= pid_list->pid_max)
562 break;
563
564 pid = (pid_t)val;
565
566 set_bit(pid, pid_list->pids);
567 nr_pids++;
568
569 trace_parser_clear(&parser);
570 ret = 0;
571 }
572 trace_parser_put(&parser);
573
574 if (ret < 0) {
575 trace_free_pid_list(pid_list);
576 return ret;
577 }
578
579 if (!nr_pids) {
580 /* Cleared the list of pids */
581 trace_free_pid_list(pid_list);
582 read = ret;
583 pid_list = NULL;
584 }
585
586 *new_pid_list = pid_list;
587
588 return read;
589}
590
591static u64 buffer_ftrace_now(struct trace_buffer *buf, int cpu)
592{
593 u64 ts;
594
595 /* Early boot up does not have a buffer yet */
596 if (!buf->buffer)
597 return trace_clock_local();
598
599 ts = ring_buffer_time_stamp(buf->buffer, cpu);
600 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
601
602 return ts;
603}
604
605u64 ftrace_now(int cpu)
606{
607 return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
608}
609
610/**
611 * tracing_is_enabled - Show if global_trace has been disabled
612 *
613 * Shows if the global trace has been enabled or not. It uses the
614 * mirror flag "buffer_disabled" to be used in fast paths such as for
615 * the irqsoff tracer. But it may be inaccurate due to races. If you
616 * need to know the accurate state, use tracing_is_on() which is a little
617 * slower, but accurate.
618 */
619int tracing_is_enabled(void)
620{
621 /*
622 * For quick access (irqsoff uses this in fast path), just
623 * return the mirror variable of the state of the ring buffer.
624 * It's a little racy, but we don't really care.
625 */
626 smp_rmb();
627 return !global_trace.buffer_disabled;
628}
629
630/*
631 * trace_buf_size is the size in bytes that is allocated
632 * for a buffer. Note, the number of bytes is always rounded
633 * to page size.
634 *
635 * This number is purposely set to a low number of 16384.
636 * If the dump on oops happens, it will be much appreciated
637 * to not have to wait for all that output. Anyway this can be
638 * boot time and run time configurable.
639 */
640#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
641
642static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
643
644/* trace_types holds a link list of available tracers. */
645static struct tracer *trace_types __read_mostly;
646
647/*
648 * trace_types_lock is used to protect the trace_types list.
649 */
650DEFINE_MUTEX(trace_types_lock);
651
652/*
653 * serialize the access of the ring buffer
654 *
655 * ring buffer serializes readers, but it is low level protection.
656 * The validity of the events (which returns by ring_buffer_peek() ..etc)
657 * are not protected by ring buffer.
658 *
659 * The content of events may become garbage if we allow other process consumes
660 * these events concurrently:
661 * A) the page of the consumed events may become a normal page
662 * (not reader page) in ring buffer, and this page will be rewrited
663 * by events producer.
664 * B) The page of the consumed events may become a page for splice_read,
665 * and this page will be returned to system.
666 *
667 * These primitives allow multi process access to different cpu ring buffer
668 * concurrently.
669 *
670 * These primitives don't distinguish read-only and read-consume access.
671 * Multi read-only access are also serialized.
672 */
673
674#ifdef CONFIG_SMP
675static DECLARE_RWSEM(all_cpu_access_lock);
676static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
677
678static inline void trace_access_lock(int cpu)
679{
680 if (cpu == RING_BUFFER_ALL_CPUS) {
681 /* gain it for accessing the whole ring buffer. */
682 down_write(&all_cpu_access_lock);
683 } else {
684 /* gain it for accessing a cpu ring buffer. */
685
686 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
687 down_read(&all_cpu_access_lock);
688
689 /* Secondly block other access to this @cpu ring buffer. */
690 mutex_lock(&per_cpu(cpu_access_lock, cpu));
691 }
692}
693
694static inline void trace_access_unlock(int cpu)
695{
696 if (cpu == RING_BUFFER_ALL_CPUS) {
697 up_write(&all_cpu_access_lock);
698 } else {
699 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
700 up_read(&all_cpu_access_lock);
701 }
702}
703
704static inline void trace_access_lock_init(void)
705{
706 int cpu;
707
708 for_each_possible_cpu(cpu)
709 mutex_init(&per_cpu(cpu_access_lock, cpu));
710}
711
712#else
713
714static DEFINE_MUTEX(access_lock);
715
716static inline void trace_access_lock(int cpu)
717{
718 (void)cpu;
719 mutex_lock(&access_lock);
720}
721
722static inline void trace_access_unlock(int cpu)
723{
724 (void)cpu;
725 mutex_unlock(&access_lock);
726}
727
728static inline void trace_access_lock_init(void)
729{
730}
731
732#endif
733
734#ifdef CONFIG_STACKTRACE
735static void __ftrace_trace_stack(struct ring_buffer *buffer,
736 unsigned long flags,
737 int skip, int pc, struct pt_regs *regs);
738static inline void ftrace_trace_stack(struct trace_array *tr,
739 struct ring_buffer *buffer,
740 unsigned long flags,
741 int skip, int pc, struct pt_regs *regs);
742
743#else
744static inline void __ftrace_trace_stack(struct ring_buffer *buffer,
745 unsigned long flags,
746 int skip, int pc, struct pt_regs *regs)
747{
748}
749static inline void ftrace_trace_stack(struct trace_array *tr,
750 struct ring_buffer *buffer,
751 unsigned long flags,
752 int skip, int pc, struct pt_regs *regs)
753{
754}
755
756#endif
757
758static __always_inline void
759trace_event_setup(struct ring_buffer_event *event,
760 int type, unsigned long flags, int pc)
761{
762 struct trace_entry *ent = ring_buffer_event_data(event);
763
764 tracing_generic_entry_update(ent, type, flags, pc);
765}
766
767static __always_inline struct ring_buffer_event *
768__trace_buffer_lock_reserve(struct ring_buffer *buffer,
769 int type,
770 unsigned long len,
771 unsigned long flags, int pc)
772{
773 struct ring_buffer_event *event;
774
775 event = ring_buffer_lock_reserve(buffer, len);
776 if (event != NULL)
777 trace_event_setup(event, type, flags, pc);
778
779 return event;
780}
781
782void tracer_tracing_on(struct trace_array *tr)
783{
784 if (tr->trace_buffer.buffer)
785 ring_buffer_record_on(tr->trace_buffer.buffer);
786 /*
787 * This flag is looked at when buffers haven't been allocated
788 * yet, or by some tracers (like irqsoff), that just want to
789 * know if the ring buffer has been disabled, but it can handle
790 * races of where it gets disabled but we still do a record.
791 * As the check is in the fast path of the tracers, it is more
792 * important to be fast than accurate.
793 */
794 tr->buffer_disabled = 0;
795 /* Make the flag seen by readers */
796 smp_wmb();
797}
798
799/**
800 * tracing_on - enable tracing buffers
801 *
802 * This function enables tracing buffers that may have been
803 * disabled with tracing_off.
804 */
805void tracing_on(void)
806{
807 tracer_tracing_on(&global_trace);
808}
809EXPORT_SYMBOL_GPL(tracing_on);
810
811
812static __always_inline void
813__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
814{
815 __this_cpu_write(trace_taskinfo_save, true);
816
817 /* If this is the temp buffer, we need to commit fully */
818 if (this_cpu_read(trace_buffered_event) == event) {
819 /* Length is in event->array[0] */
820 ring_buffer_write(buffer, event->array[0], &event->array[1]);
821 /* Release the temp buffer */
822 this_cpu_dec(trace_buffered_event_cnt);
823 } else
824 ring_buffer_unlock_commit(buffer, event);
825}
826
827/**
828 * __trace_puts - write a constant string into the trace buffer.
829 * @ip: The address of the caller
830 * @str: The constant string to write
831 * @size: The size of the string.
832 */
833int __trace_puts(unsigned long ip, const char *str, int size)
834{
835 struct ring_buffer_event *event;
836 struct ring_buffer *buffer;
837 struct print_entry *entry;
838 unsigned long irq_flags;
839 int alloc;
840 int pc;
841
842 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
843 return 0;
844
845 pc = preempt_count();
846
847 if (unlikely(tracing_selftest_running || tracing_disabled))
848 return 0;
849
850 alloc = sizeof(*entry) + size + 2; /* possible \n added */
851
852 local_save_flags(irq_flags);
853 buffer = global_trace.trace_buffer.buffer;
854 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
855 irq_flags, pc);
856 if (!event)
857 return 0;
858
859 entry = ring_buffer_event_data(event);
860 entry->ip = ip;
861
862 memcpy(&entry->buf, str, size);
863
864 /* Add a newline if necessary */
865 if (entry->buf[size - 1] != '\n') {
866 entry->buf[size] = '\n';
867 entry->buf[size + 1] = '\0';
868 } else
869 entry->buf[size] = '\0';
870
871 __buffer_unlock_commit(buffer, event);
872 ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
873
874 return size;
875}
876EXPORT_SYMBOL_GPL(__trace_puts);
877
878/**
879 * __trace_bputs - write the pointer to a constant string into trace buffer
880 * @ip: The address of the caller
881 * @str: The constant string to write to the buffer to
882 */
883int __trace_bputs(unsigned long ip, const char *str)
884{
885 struct ring_buffer_event *event;
886 struct ring_buffer *buffer;
887 struct bputs_entry *entry;
888 unsigned long irq_flags;
889 int size = sizeof(struct bputs_entry);
890 int pc;
891
892 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
893 return 0;
894
895 pc = preempt_count();
896
897 if (unlikely(tracing_selftest_running || tracing_disabled))
898 return 0;
899
900 local_save_flags(irq_flags);
901 buffer = global_trace.trace_buffer.buffer;
902 event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
903 irq_flags, pc);
904 if (!event)
905 return 0;
906
907 entry = ring_buffer_event_data(event);
908 entry->ip = ip;
909 entry->str = str;
910
911 __buffer_unlock_commit(buffer, event);
912 ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
913
914 return 1;
915}
916EXPORT_SYMBOL_GPL(__trace_bputs);
917
918#ifdef CONFIG_TRACER_SNAPSHOT
919void tracing_snapshot_instance_cond(struct trace_array *tr, void *cond_data)
920{
921 struct tracer *tracer = tr->current_trace;
922 unsigned long flags;
923
924 if (in_nmi()) {
925 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
926 internal_trace_puts("*** snapshot is being ignored ***\n");
927 return;
928 }
929
930 if (!tr->allocated_snapshot) {
931 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
932 internal_trace_puts("*** stopping trace here! ***\n");
933 tracing_off();
934 return;
935 }
936
937 /* Note, snapshot can not be used when the tracer uses it */
938 if (tracer->use_max_tr) {
939 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
940 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
941 return;
942 }
943
944 local_irq_save(flags);
945 update_max_tr(tr, current, smp_processor_id(), cond_data);
946 local_irq_restore(flags);
947}
948
949void tracing_snapshot_instance(struct trace_array *tr)
950{
951 tracing_snapshot_instance_cond(tr, NULL);
952}
953
954/**
955 * tracing_snapshot - take a snapshot of the current buffer.
956 *
957 * This causes a swap between the snapshot buffer and the current live
958 * tracing buffer. You can use this to take snapshots of the live
959 * trace when some condition is triggered, but continue to trace.
960 *
961 * Note, make sure to allocate the snapshot with either
962 * a tracing_snapshot_alloc(), or by doing it manually
963 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
964 *
965 * If the snapshot buffer is not allocated, it will stop tracing.
966 * Basically making a permanent snapshot.
967 */
968void tracing_snapshot(void)
969{
970 struct trace_array *tr = &global_trace;
971
972 tracing_snapshot_instance(tr);
973}
974EXPORT_SYMBOL_GPL(tracing_snapshot);
975
976/**
977 * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
978 * @tr: The tracing instance to snapshot
979 * @cond_data: The data to be tested conditionally, and possibly saved
980 *
981 * This is the same as tracing_snapshot() except that the snapshot is
982 * conditional - the snapshot will only happen if the
983 * cond_snapshot.update() implementation receiving the cond_data
984 * returns true, which means that the trace array's cond_snapshot
985 * update() operation used the cond_data to determine whether the
986 * snapshot should be taken, and if it was, presumably saved it along
987 * with the snapshot.
988 */
989void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
990{
991 tracing_snapshot_instance_cond(tr, cond_data);
992}
993EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
994
995/**
996 * tracing_snapshot_cond_data - get the user data associated with a snapshot
997 * @tr: The tracing instance
998 *
999 * When the user enables a conditional snapshot using
1000 * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
1001 * with the snapshot. This accessor is used to retrieve it.
1002 *
1003 * Should not be called from cond_snapshot.update(), since it takes
1004 * the tr->max_lock lock, which the code calling
1005 * cond_snapshot.update() has already done.
1006 *
1007 * Returns the cond_data associated with the trace array's snapshot.
1008 */
1009void *tracing_cond_snapshot_data(struct trace_array *tr)
1010{
1011 void *cond_data = NULL;
1012
1013 arch_spin_lock(&tr->max_lock);
1014
1015 if (tr->cond_snapshot)
1016 cond_data = tr->cond_snapshot->cond_data;
1017
1018 arch_spin_unlock(&tr->max_lock);
1019
1020 return cond_data;
1021}
1022EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1023
1024static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
1025 struct trace_buffer *size_buf, int cpu_id);
1026static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
1027
1028int tracing_alloc_snapshot_instance(struct trace_array *tr)
1029{
1030 int ret;
1031
1032 if (!tr->allocated_snapshot) {
1033
1034 /* allocate spare buffer */
1035 ret = resize_buffer_duplicate_size(&tr->max_buffer,
1036 &tr->trace_buffer, RING_BUFFER_ALL_CPUS);
1037 if (ret < 0)
1038 return ret;
1039
1040 tr->allocated_snapshot = true;
1041 }
1042
1043 return 0;
1044}
1045
1046static void free_snapshot(struct trace_array *tr)
1047{
1048 /*
1049 * We don't free the ring buffer. instead, resize it because
1050 * The max_tr ring buffer has some state (e.g. ring->clock) and
1051 * we want preserve it.
1052 */
1053 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
1054 set_buffer_entries(&tr->max_buffer, 1);
1055 tracing_reset_online_cpus(&tr->max_buffer);
1056 tr->allocated_snapshot = false;
1057}
1058
1059/**
1060 * tracing_alloc_snapshot - allocate snapshot buffer.
1061 *
1062 * This only allocates the snapshot buffer if it isn't already
1063 * allocated - it doesn't also take a snapshot.
1064 *
1065 * This is meant to be used in cases where the snapshot buffer needs
1066 * to be set up for events that can't sleep but need to be able to
1067 * trigger a snapshot.
1068 */
1069int tracing_alloc_snapshot(void)
1070{
1071 struct trace_array *tr = &global_trace;
1072 int ret;
1073
1074 ret = tracing_alloc_snapshot_instance(tr);
1075 WARN_ON(ret < 0);
1076
1077 return ret;
1078}
1079EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1080
1081/**
1082 * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
1083 *
1084 * This is similar to tracing_snapshot(), but it will allocate the
1085 * snapshot buffer if it isn't already allocated. Use this only
1086 * where it is safe to sleep, as the allocation may sleep.
1087 *
1088 * This causes a swap between the snapshot buffer and the current live
1089 * tracing buffer. You can use this to take snapshots of the live
1090 * trace when some condition is triggered, but continue to trace.
1091 */
1092void tracing_snapshot_alloc(void)
1093{
1094 int ret;
1095
1096 ret = tracing_alloc_snapshot();
1097 if (ret < 0)
1098 return;
1099
1100 tracing_snapshot();
1101}
1102EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1103
1104/**
1105 * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
1106 * @tr: The tracing instance
1107 * @cond_data: User data to associate with the snapshot
1108 * @update: Implementation of the cond_snapshot update function
1109 *
1110 * Check whether the conditional snapshot for the given instance has
1111 * already been enabled, or if the current tracer is already using a
1112 * snapshot; if so, return -EBUSY, else create a cond_snapshot and
1113 * save the cond_data and update function inside.
1114 *
1115 * Returns 0 if successful, error otherwise.
1116 */
1117int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
1118 cond_update_fn_t update)
1119{
1120 struct cond_snapshot *cond_snapshot;
1121 int ret = 0;
1122
1123 cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
1124 if (!cond_snapshot)
1125 return -ENOMEM;
1126
1127 cond_snapshot->cond_data = cond_data;
1128 cond_snapshot->update = update;
1129
1130 mutex_lock(&trace_types_lock);
1131
1132 ret = tracing_alloc_snapshot_instance(tr);
1133 if (ret)
1134 goto fail_unlock;
1135
1136 if (tr->current_trace->use_max_tr) {
1137 ret = -EBUSY;
1138 goto fail_unlock;
1139 }
1140
1141 /*
1142 * The cond_snapshot can only change to NULL without the
1143 * trace_types_lock. We don't care if we race with it going
1144 * to NULL, but we want to make sure that it's not set to
1145 * something other than NULL when we get here, which we can
1146 * do safely with only holding the trace_types_lock and not
1147 * having to take the max_lock.
1148 */
1149 if (tr->cond_snapshot) {
1150 ret = -EBUSY;
1151 goto fail_unlock;
1152 }
1153
1154 arch_spin_lock(&tr->max_lock);
1155 tr->cond_snapshot = cond_snapshot;
1156 arch_spin_unlock(&tr->max_lock);
1157
1158 mutex_unlock(&trace_types_lock);
1159
1160 return ret;
1161
1162 fail_unlock:
1163 mutex_unlock(&trace_types_lock);
1164 kfree(cond_snapshot);
1165 return ret;
1166}
1167EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1168
1169/**
1170 * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
1171 * @tr: The tracing instance
1172 *
1173 * Check whether the conditional snapshot for the given instance is
1174 * enabled; if so, free the cond_snapshot associated with it,
1175 * otherwise return -EINVAL.
1176 *
1177 * Returns 0 if successful, error otherwise.
1178 */
1179int tracing_snapshot_cond_disable(struct trace_array *tr)
1180{
1181 int ret = 0;
1182
1183 arch_spin_lock(&tr->max_lock);
1184
1185 if (!tr->cond_snapshot)
1186 ret = -EINVAL;
1187 else {
1188 kfree(tr->cond_snapshot);
1189 tr->cond_snapshot = NULL;
1190 }
1191
1192 arch_spin_unlock(&tr->max_lock);
1193
1194 return ret;
1195}
1196EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1197#else
1198void tracing_snapshot(void)
1199{
1200 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
1201}
1202EXPORT_SYMBOL_GPL(tracing_snapshot);
1203void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1204{
1205 WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
1206}
1207EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1208int tracing_alloc_snapshot(void)
1209{
1210 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
1211 return -ENODEV;
1212}
1213EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1214void tracing_snapshot_alloc(void)
1215{
1216 /* Give warning */
1217 tracing_snapshot();
1218}
1219EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1220void *tracing_cond_snapshot_data(struct trace_array *tr)
1221{
1222 return NULL;
1223}
1224EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1225int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
1226{
1227 return -ENODEV;
1228}
1229EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1230int tracing_snapshot_cond_disable(struct trace_array *tr)
1231{
1232 return false;
1233}
1234EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1235#endif /* CONFIG_TRACER_SNAPSHOT */
1236
1237void tracer_tracing_off(struct trace_array *tr)
1238{
1239 if (tr->trace_buffer.buffer)
1240 ring_buffer_record_off(tr->trace_buffer.buffer);
1241 /*
1242 * This flag is looked at when buffers haven't been allocated
1243 * yet, or by some tracers (like irqsoff), that just want to
1244 * know if the ring buffer has been disabled, but it can handle
1245 * races of where it gets disabled but we still do a record.
1246 * As the check is in the fast path of the tracers, it is more
1247 * important to be fast than accurate.
1248 */
1249 tr->buffer_disabled = 1;
1250 /* Make the flag seen by readers */
1251 smp_wmb();
1252}
1253
1254/**
1255 * tracing_off - turn off tracing buffers
1256 *
1257 * This function stops the tracing buffers from recording data.
1258 * It does not disable any overhead the tracers themselves may
1259 * be causing. This function simply causes all recording to
1260 * the ring buffers to fail.
1261 */
1262void tracing_off(void)
1263{
1264 tracer_tracing_off(&global_trace);
1265}
1266EXPORT_SYMBOL_GPL(tracing_off);
1267
1268void disable_trace_on_warning(void)
1269{
1270 if (__disable_trace_on_warning)
1271 tracing_off();
1272}
1273
1274/**
1275 * tracer_tracing_is_on - show real state of ring buffer enabled
1276 * @tr : the trace array to know if ring buffer is enabled
1277 *
1278 * Shows real state of the ring buffer if it is enabled or not.
1279 */
1280bool tracer_tracing_is_on(struct trace_array *tr)
1281{
1282 if (tr->trace_buffer.buffer)
1283 return ring_buffer_record_is_on(tr->trace_buffer.buffer);
1284 return !tr->buffer_disabled;
1285}
1286
1287/**
1288 * tracing_is_on - show state of ring buffers enabled
1289 */
1290int tracing_is_on(void)
1291{
1292 return tracer_tracing_is_on(&global_trace);
1293}
1294EXPORT_SYMBOL_GPL(tracing_is_on);
1295
1296static int __init set_buf_size(char *str)
1297{
1298 unsigned long buf_size;
1299
1300 if (!str)
1301 return 0;
1302 buf_size = memparse(str, &str);
1303 /* nr_entries can not be zero */
1304 if (buf_size == 0)
1305 return 0;
1306 trace_buf_size = buf_size;
1307 return 1;
1308}
1309__setup("trace_buf_size=", set_buf_size);
1310
1311static int __init set_tracing_thresh(char *str)
1312{
1313 unsigned long threshold;
1314 int ret;
1315
1316 if (!str)
1317 return 0;
1318 ret = kstrtoul(str, 0, &threshold);
1319 if (ret < 0)
1320 return 0;
1321 tracing_thresh = threshold * 1000;
1322 return 1;
1323}
1324__setup("tracing_thresh=", set_tracing_thresh);
1325
1326unsigned long nsecs_to_usecs(unsigned long nsecs)
1327{
1328 return nsecs / 1000;
1329}
1330
1331/*
1332 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
1333 * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
1334 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
1335 * of strings in the order that the evals (enum) were defined.
1336 */
1337#undef C
1338#define C(a, b) b
1339
1340/* These must match the bit postions in trace_iterator_flags */
1341static const char *trace_options[] = {
1342 TRACE_FLAGS
1343 NULL
1344};
1345
1346static struct {
1347 u64 (*func)(void);
1348 const char *name;
1349 int in_ns; /* is this clock in nanoseconds? */
1350} trace_clocks[] = {
1351 { trace_clock_local, "local", 1 },
1352 { trace_clock_global, "global", 1 },
1353 { trace_clock_counter, "counter", 0 },
1354 { trace_clock_jiffies, "uptime", 0 },
1355 { trace_clock, "perf", 1 },
1356 { ktime_get_mono_fast_ns, "mono", 1 },
1357 { ktime_get_raw_fast_ns, "mono_raw", 1 },
1358 { ktime_get_boot_fast_ns, "boot", 1 },
1359 ARCH_TRACE_CLOCKS
1360};
1361
1362bool trace_clock_in_ns(struct trace_array *tr)
1363{
1364 if (trace_clocks[tr->clock_id].in_ns)
1365 return true;
1366
1367 return false;
1368}
1369
1370/*
1371 * trace_parser_get_init - gets the buffer for trace parser
1372 */
1373int trace_parser_get_init(struct trace_parser *parser, int size)
1374{
1375 memset(parser, 0, sizeof(*parser));
1376
1377 parser->buffer = kmalloc(size, GFP_KERNEL);
1378 if (!parser->buffer)
1379 return 1;
1380
1381 parser->size = size;
1382 return 0;
1383}
1384
1385/*
1386 * trace_parser_put - frees the buffer for trace parser
1387 */
1388void trace_parser_put(struct trace_parser *parser)
1389{
1390 kfree(parser->buffer);
1391 parser->buffer = NULL;
1392}
1393
1394/*
1395 * trace_get_user - reads the user input string separated by space
1396 * (matched by isspace(ch))
1397 *
1398 * For each string found the 'struct trace_parser' is updated,
1399 * and the function returns.
1400 *
1401 * Returns number of bytes read.
1402 *
1403 * See kernel/trace/trace.h for 'struct trace_parser' details.
1404 */
1405int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1406 size_t cnt, loff_t *ppos)
1407{
1408 char ch;
1409 size_t read = 0;
1410 ssize_t ret;
1411
1412 if (!*ppos)
1413 trace_parser_clear(parser);
1414
1415 ret = get_user(ch, ubuf++);
1416 if (ret)
1417 goto out;
1418
1419 read++;
1420 cnt--;
1421
1422 /*
1423 * The parser is not finished with the last write,
1424 * continue reading the user input without skipping spaces.
1425 */
1426 if (!parser->cont) {
1427 /* skip white space */
1428 while (cnt && isspace(ch)) {
1429 ret = get_user(ch, ubuf++);
1430 if (ret)
1431 goto out;
1432 read++;
1433 cnt--;
1434 }
1435
1436 parser->idx = 0;
1437
1438 /* only spaces were written */
1439 if (isspace(ch) || !ch) {
1440 *ppos += read;
1441 ret = read;
1442 goto out;
1443 }
1444 }
1445
1446 /* read the non-space input */
1447 while (cnt && !isspace(ch) && ch) {
1448 if (parser->idx < parser->size - 1)
1449 parser->buffer[parser->idx++] = ch;
1450 else {
1451 ret = -EINVAL;
1452 goto out;
1453 }
1454 ret = get_user(ch, ubuf++);
1455 if (ret)
1456 goto out;
1457 read++;
1458 cnt--;
1459 }
1460
1461 /* We either got finished input or we have to wait for another call. */
1462 if (isspace(ch) || !ch) {
1463 parser->buffer[parser->idx] = 0;
1464 parser->cont = false;
1465 } else if (parser->idx < parser->size - 1) {
1466 parser->cont = true;
1467 parser->buffer[parser->idx++] = ch;
1468 /* Make sure the parsed string always terminates with '\0'. */
1469 parser->buffer[parser->idx] = 0;
1470 } else {
1471 ret = -EINVAL;
1472 goto out;
1473 }
1474
1475 *ppos += read;
1476 ret = read;
1477
1478out:
1479 return ret;
1480}
1481
1482/* TODO add a seq_buf_to_buffer() */
1483static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1484{
1485 int len;
1486
1487 if (trace_seq_used(s) <= s->seq.readpos)
1488 return -EBUSY;
1489
1490 len = trace_seq_used(s) - s->seq.readpos;
1491 if (cnt > len)
1492 cnt = len;
1493 memcpy(buf, s->buffer + s->seq.readpos, cnt);
1494
1495 s->seq.readpos += cnt;
1496 return cnt;
1497}
1498
1499unsigned long __read_mostly tracing_thresh;
1500
1501#ifdef CONFIG_TRACER_MAX_TRACE
1502/*
1503 * Copy the new maximum trace into the separate maximum-trace
1504 * structure. (this way the maximum trace is permanently saved,
1505 * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
1506 */
1507static void
1508__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1509{
1510 struct trace_buffer *trace_buf = &tr->trace_buffer;
1511 struct trace_buffer *max_buf = &tr->max_buffer;
1512 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1513 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1514
1515 max_buf->cpu = cpu;
1516 max_buf->time_start = data->preempt_timestamp;
1517
1518 max_data->saved_latency = tr->max_latency;
1519 max_data->critical_start = data->critical_start;
1520 max_data->critical_end = data->critical_end;
1521
1522 strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1523 max_data->pid = tsk->pid;
1524 /*
1525 * If tsk == current, then use current_uid(), as that does not use
1526 * RCU. The irq tracer can be called out of RCU scope.
1527 */
1528 if (tsk == current)
1529 max_data->uid = current_uid();
1530 else
1531 max_data->uid = task_uid(tsk);
1532
1533 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1534 max_data->policy = tsk->policy;
1535 max_data->rt_priority = tsk->rt_priority;
1536
1537 /* record this tasks comm */
1538 tracing_record_cmdline(tsk);
1539}
1540
1541/**
1542 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1543 * @tr: tracer
1544 * @tsk: the task with the latency
1545 * @cpu: The cpu that initiated the trace.
1546 * @cond_data: User data associated with a conditional snapshot
1547 *
1548 * Flip the buffers between the @tr and the max_tr and record information
1549 * about which task was the cause of this latency.
1550 */
1551void
1552update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
1553 void *cond_data)
1554{
1555 if (tr->stop_count)
1556 return;
1557
1558 WARN_ON_ONCE(!irqs_disabled());
1559
1560 if (!tr->allocated_snapshot) {
1561 /* Only the nop tracer should hit this when disabling */
1562 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1563 return;
1564 }
1565
1566 arch_spin_lock(&tr->max_lock);
1567
1568 /* Inherit the recordable setting from trace_buffer */
1569 if (ring_buffer_record_is_set_on(tr->trace_buffer.buffer))
1570 ring_buffer_record_on(tr->max_buffer.buffer);
1571 else
1572 ring_buffer_record_off(tr->max_buffer.buffer);
1573
1574#ifdef CONFIG_TRACER_SNAPSHOT
1575 if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data))
1576 goto out_unlock;
1577#endif
1578 swap(tr->trace_buffer.buffer, tr->max_buffer.buffer);
1579
1580 __update_max_tr(tr, tsk, cpu);
1581
1582 out_unlock:
1583 arch_spin_unlock(&tr->max_lock);
1584}
1585
1586/**
1587 * update_max_tr_single - only copy one trace over, and reset the rest
1588 * @tr: tracer
1589 * @tsk: task with the latency
1590 * @cpu: the cpu of the buffer to copy.
1591 *
1592 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1593 */
1594void
1595update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1596{
1597 int ret;
1598
1599 if (tr->stop_count)
1600 return;
1601
1602 WARN_ON_ONCE(!irqs_disabled());
1603 if (!tr->allocated_snapshot) {
1604 /* Only the nop tracer should hit this when disabling */
1605 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1606 return;
1607 }
1608
1609 arch_spin_lock(&tr->max_lock);
1610
1611 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
1612
1613 if (ret == -EBUSY) {
1614 /*
1615 * We failed to swap the buffer due to a commit taking
1616 * place on this CPU. We fail to record, but we reset
1617 * the max trace buffer (no one writes directly to it)
1618 * and flag that it failed.
1619 */
1620 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1621 "Failed to swap buffers due to commit in progress\n");
1622 }
1623
1624 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1625
1626 __update_max_tr(tr, tsk, cpu);
1627 arch_spin_unlock(&tr->max_lock);
1628}
1629#endif /* CONFIG_TRACER_MAX_TRACE */
1630
1631static int wait_on_pipe(struct trace_iterator *iter, int full)
1632{
1633 /* Iterators are static, they should be filled or empty */
1634 if (trace_buffer_iter(iter, iter->cpu_file))
1635 return 0;
1636
1637 return ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file,
1638 full);
1639}
1640
1641#ifdef CONFIG_FTRACE_STARTUP_TEST
1642static bool selftests_can_run;
1643
1644struct trace_selftests {
1645 struct list_head list;
1646 struct tracer *type;
1647};
1648
1649static LIST_HEAD(postponed_selftests);
1650
1651static int save_selftest(struct tracer *type)
1652{
1653 struct trace_selftests *selftest;
1654
1655 selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
1656 if (!selftest)
1657 return -ENOMEM;
1658
1659 selftest->type = type;
1660 list_add(&selftest->list, &postponed_selftests);
1661 return 0;
1662}
1663
1664static int run_tracer_selftest(struct tracer *type)
1665{
1666 struct trace_array *tr = &global_trace;
1667 struct tracer *saved_tracer = tr->current_trace;
1668 int ret;
1669
1670 if (!type->selftest || tracing_selftest_disabled)
1671 return 0;
1672
1673 /*
1674 * If a tracer registers early in boot up (before scheduling is
1675 * initialized and such), then do not run its selftests yet.
1676 * Instead, run it a little later in the boot process.
1677 */
1678 if (!selftests_can_run)
1679 return save_selftest(type);
1680
1681 /*
1682 * Run a selftest on this tracer.
1683 * Here we reset the trace buffer, and set the current
1684 * tracer to be this tracer. The tracer can then run some
1685 * internal tracing to verify that everything is in order.
1686 * If we fail, we do not register this tracer.
1687 */
1688 tracing_reset_online_cpus(&tr->trace_buffer);
1689
1690 tr->current_trace = type;
1691
1692#ifdef CONFIG_TRACER_MAX_TRACE
1693 if (type->use_max_tr) {
1694 /* If we expanded the buffers, make sure the max is expanded too */
1695 if (ring_buffer_expanded)
1696 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
1697 RING_BUFFER_ALL_CPUS);
1698 tr->allocated_snapshot = true;
1699 }
1700#endif
1701
1702 /* the test is responsible for initializing and enabling */
1703 pr_info("Testing tracer %s: ", type->name);
1704 ret = type->selftest(type, tr);
1705 /* the test is responsible for resetting too */
1706 tr->current_trace = saved_tracer;
1707 if (ret) {
1708 printk(KERN_CONT "FAILED!\n");
1709 /* Add the warning after printing 'FAILED' */
1710 WARN_ON(1);
1711 return -1;
1712 }
1713 /* Only reset on passing, to avoid touching corrupted buffers */
1714 tracing_reset_online_cpus(&tr->trace_buffer);
1715
1716#ifdef CONFIG_TRACER_MAX_TRACE
1717 if (type->use_max_tr) {
1718 tr->allocated_snapshot = false;
1719
1720 /* Shrink the max buffer again */
1721 if (ring_buffer_expanded)
1722 ring_buffer_resize(tr->max_buffer.buffer, 1,
1723 RING_BUFFER_ALL_CPUS);
1724 }
1725#endif
1726
1727 printk(KERN_CONT "PASSED\n");
1728 return 0;
1729}
1730
1731static __init int init_trace_selftests(void)
1732{
1733 struct trace_selftests *p, *n;
1734 struct tracer *t, **last;
1735 int ret;
1736
1737 selftests_can_run = true;
1738
1739 mutex_lock(&trace_types_lock);
1740
1741 if (list_empty(&postponed_selftests))
1742 goto out;
1743
1744 pr_info("Running postponed tracer tests:\n");
1745
1746 list_for_each_entry_safe(p, n, &postponed_selftests, list) {
1747 /* This loop can take minutes when sanitizers are enabled, so
1748 * lets make sure we allow RCU processing.
1749 */
1750 cond_resched();
1751 ret = run_tracer_selftest(p->type);
1752 /* If the test fails, then warn and remove from available_tracers */
1753 if (ret < 0) {
1754 WARN(1, "tracer: %s failed selftest, disabling\n",
1755 p->type->name);
1756 last = &trace_types;
1757 for (t = trace_types; t; t = t->next) {
1758 if (t == p->type) {
1759 *last = t->next;
1760 break;
1761 }
1762 last = &t->next;
1763 }
1764 }
1765 list_del(&p->list);
1766 kfree(p);
1767 }
1768
1769 out:
1770 mutex_unlock(&trace_types_lock);
1771
1772 return 0;
1773}
1774core_initcall(init_trace_selftests);
1775#else
1776static inline int run_tracer_selftest(struct tracer *type)
1777{
1778 return 0;
1779}
1780#endif /* CONFIG_FTRACE_STARTUP_TEST */
1781
1782static void add_tracer_options(struct trace_array *tr, struct tracer *t);
1783
1784static void __init apply_trace_boot_options(void);
1785
1786/**
1787 * register_tracer - register a tracer with the ftrace system.
1788 * @type: the plugin for the tracer
1789 *
1790 * Register a new plugin tracer.
1791 */
1792int __init register_tracer(struct tracer *type)
1793{
1794 struct tracer *t;
1795 int ret = 0;
1796
1797 if (!type->name) {
1798 pr_info("Tracer must have a name\n");
1799 return -1;
1800 }
1801
1802 if (strlen(type->name) >= MAX_TRACER_SIZE) {
1803 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
1804 return -1;
1805 }
1806
1807 mutex_lock(&trace_types_lock);
1808
1809 tracing_selftest_running = true;
1810
1811 for (t = trace_types; t; t = t->next) {
1812 if (strcmp(type->name, t->name) == 0) {
1813 /* already found */
1814 pr_info("Tracer %s already registered\n",
1815 type->name);
1816 ret = -1;
1817 goto out;
1818 }
1819 }
1820
1821 if (!type->set_flag)
1822 type->set_flag = &dummy_set_flag;
1823 if (!type->flags) {
1824 /*allocate a dummy tracer_flags*/
1825 type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
1826 if (!type->flags) {
1827 ret = -ENOMEM;
1828 goto out;
1829 }
1830 type->flags->val = 0;
1831 type->flags->opts = dummy_tracer_opt;
1832 } else
1833 if (!type->flags->opts)
1834 type->flags->opts = dummy_tracer_opt;
1835
1836 /* store the tracer for __set_tracer_option */
1837 type->flags->trace = type;
1838
1839 ret = run_tracer_selftest(type);
1840 if (ret < 0)
1841 goto out;
1842
1843 type->next = trace_types;
1844 trace_types = type;
1845 add_tracer_options(&global_trace, type);
1846
1847 out:
1848 tracing_selftest_running = false;
1849 mutex_unlock(&trace_types_lock);
1850
1851 if (ret || !default_bootup_tracer)
1852 goto out_unlock;
1853
1854 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
1855 goto out_unlock;
1856
1857 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
1858 /* Do we want this tracer to start on bootup? */
1859 tracing_set_tracer(&global_trace, type->name);
1860 default_bootup_tracer = NULL;
1861
1862 apply_trace_boot_options();
1863
1864 /* disable other selftests, since this will break it. */
1865 tracing_selftest_disabled = true;
1866#ifdef CONFIG_FTRACE_STARTUP_TEST
1867 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
1868 type->name);
1869#endif
1870
1871 out_unlock:
1872 return ret;
1873}
1874
1875static void tracing_reset_cpu(struct trace_buffer *buf, int cpu)
1876{
1877 struct ring_buffer *buffer = buf->buffer;
1878
1879 if (!buffer)
1880 return;
1881
1882 ring_buffer_record_disable(buffer);
1883
1884 /* Make sure all commits have finished */
1885 synchronize_rcu();
1886 ring_buffer_reset_cpu(buffer, cpu);
1887
1888 ring_buffer_record_enable(buffer);
1889}
1890
1891void tracing_reset_online_cpus(struct trace_buffer *buf)
1892{
1893 struct ring_buffer *buffer = buf->buffer;
1894 int cpu;
1895
1896 if (!buffer)
1897 return;
1898
1899 ring_buffer_record_disable(buffer);
1900
1901 /* Make sure all commits have finished */
1902 synchronize_rcu();
1903
1904 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
1905
1906 for_each_online_cpu(cpu)
1907 ring_buffer_reset_cpu(buffer, cpu);
1908
1909 ring_buffer_record_enable(buffer);
1910}
1911
1912/* Must have trace_types_lock held */
1913void tracing_reset_all_online_cpus(void)
1914{
1915 struct trace_array *tr;
1916
1917 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1918 if (!tr->clear_trace)
1919 continue;
1920 tr->clear_trace = false;
1921 tracing_reset_online_cpus(&tr->trace_buffer);
1922#ifdef CONFIG_TRACER_MAX_TRACE
1923 tracing_reset_online_cpus(&tr->max_buffer);
1924#endif
1925 }
1926}
1927
1928static int *tgid_map;
1929
1930#define SAVED_CMDLINES_DEFAULT 128
1931#define NO_CMDLINE_MAP UINT_MAX
1932static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1933struct saved_cmdlines_buffer {
1934 unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
1935 unsigned *map_cmdline_to_pid;
1936 unsigned cmdline_num;
1937 int cmdline_idx;
1938 char *saved_cmdlines;
1939};
1940static struct saved_cmdlines_buffer *savedcmd;
1941
1942/* temporary disable recording */
1943static atomic_t trace_record_taskinfo_disabled __read_mostly;
1944
1945static inline char *get_saved_cmdlines(int idx)
1946{
1947 return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
1948}
1949
1950static inline void set_cmdline(int idx, const char *cmdline)
1951{
1952 strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
1953}
1954
1955static int allocate_cmdlines_buffer(unsigned int val,
1956 struct saved_cmdlines_buffer *s)
1957{
1958 s->map_cmdline_to_pid = kmalloc_array(val,
1959 sizeof(*s->map_cmdline_to_pid),
1960 GFP_KERNEL);
1961 if (!s->map_cmdline_to_pid)
1962 return -ENOMEM;
1963
1964 s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL);
1965 if (!s->saved_cmdlines) {
1966 kfree(s->map_cmdline_to_pid);
1967 return -ENOMEM;
1968 }
1969
1970 s->cmdline_idx = 0;
1971 s->cmdline_num = val;
1972 memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
1973 sizeof(s->map_pid_to_cmdline));
1974 memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
1975 val * sizeof(*s->map_cmdline_to_pid));
1976
1977 return 0;
1978}
1979
1980static int trace_create_savedcmd(void)
1981{
1982 int ret;
1983
1984 savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
1985 if (!savedcmd)
1986 return -ENOMEM;
1987
1988 ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
1989 if (ret < 0) {
1990 kfree(savedcmd);
1991 savedcmd = NULL;
1992 return -ENOMEM;
1993 }
1994
1995 return 0;
1996}
1997
1998int is_tracing_stopped(void)
1999{
2000 return global_trace.stop_count;
2001}
2002
2003/**
2004 * tracing_start - quick start of the tracer
2005 *
2006 * If tracing is enabled but was stopped by tracing_stop,
2007 * this will start the tracer back up.
2008 */
2009void tracing_start(void)
2010{
2011 struct ring_buffer *buffer;
2012 unsigned long flags;
2013
2014 if (tracing_disabled)
2015 return;
2016
2017 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
2018 if (--global_trace.stop_count) {
2019 if (global_trace.stop_count < 0) {
2020 /* Someone screwed up their debugging */
2021 WARN_ON_ONCE(1);
2022 global_trace.stop_count = 0;
2023 }
2024 goto out;
2025 }
2026
2027 /* Prevent the buffers from switching */
2028 arch_spin_lock(&global_trace.max_lock);
2029
2030 buffer = global_trace.trace_buffer.buffer;
2031 if (buffer)
2032 ring_buffer_record_enable(buffer);
2033
2034#ifdef CONFIG_TRACER_MAX_TRACE
2035 buffer = global_trace.max_buffer.buffer;
2036 if (buffer)
2037 ring_buffer_record_enable(buffer);
2038#endif
2039
2040 arch_spin_unlock(&global_trace.max_lock);
2041
2042 out:
2043 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
2044}
2045
2046static void tracing_start_tr(struct trace_array *tr)
2047{
2048 struct ring_buffer *buffer;
2049 unsigned long flags;
2050
2051 if (tracing_disabled)
2052 return;
2053
2054 /* If global, we need to also start the max tracer */
2055 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
2056 return tracing_start();
2057
2058 raw_spin_lock_irqsave(&tr->start_lock, flags);
2059
2060 if (--tr->stop_count) {
2061 if (tr->stop_count < 0) {
2062 /* Someone screwed up their debugging */
2063 WARN_ON_ONCE(1);
2064 tr->stop_count = 0;
2065 }
2066 goto out;
2067 }
2068
2069 buffer = tr->trace_buffer.buffer;
2070 if (buffer)
2071 ring_buffer_record_enable(buffer);
2072
2073 out:
2074 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2075}
2076
2077/**
2078 * tracing_stop - quick stop of the tracer
2079 *
2080 * Light weight way to stop tracing. Use in conjunction with
2081 * tracing_start.
2082 */
2083void tracing_stop(void)
2084{
2085 struct ring_buffer *buffer;
2086 unsigned long flags;
2087
2088 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
2089 if (global_trace.stop_count++)
2090 goto out;
2091
2092 /* Prevent the buffers from switching */
2093 arch_spin_lock(&global_trace.max_lock);
2094
2095 buffer = global_trace.trace_buffer.buffer;
2096 if (buffer)
2097 ring_buffer_record_disable(buffer);
2098
2099#ifdef CONFIG_TRACER_MAX_TRACE
2100 buffer = global_trace.max_buffer.buffer;
2101 if (buffer)
2102 ring_buffer_record_disable(buffer);
2103#endif
2104
2105 arch_spin_unlock(&global_trace.max_lock);
2106
2107 out:
2108 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
2109}
2110
2111static void tracing_stop_tr(struct trace_array *tr)
2112{
2113 struct ring_buffer *buffer;
2114 unsigned long flags;
2115
2116 /* If global, we need to also stop the max tracer */
2117 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
2118 return tracing_stop();
2119
2120 raw_spin_lock_irqsave(&tr->start_lock, flags);
2121 if (tr->stop_count++)
2122 goto out;
2123
2124 buffer = tr->trace_buffer.buffer;
2125 if (buffer)
2126 ring_buffer_record_disable(buffer);
2127
2128 out:
2129 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2130}
2131
2132static int trace_save_cmdline(struct task_struct *tsk)
2133{
2134 unsigned pid, idx;
2135
2136 /* treat recording of idle task as a success */
2137 if (!tsk->pid)
2138 return 1;
2139
2140 if (unlikely(tsk->pid > PID_MAX_DEFAULT))
2141 return 0;
2142
2143 /*
2144 * It's not the end of the world if we don't get
2145 * the lock, but we also don't want to spin
2146 * nor do we want to disable interrupts,
2147 * so if we miss here, then better luck next time.
2148 */
2149 if (!arch_spin_trylock(&trace_cmdline_lock))
2150 return 0;
2151
2152 idx = savedcmd->map_pid_to_cmdline[tsk->pid];
2153 if (idx == NO_CMDLINE_MAP) {
2154 idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
2155
2156 /*
2157 * Check whether the cmdline buffer at idx has a pid
2158 * mapped. We are going to overwrite that entry so we
2159 * need to clear the map_pid_to_cmdline. Otherwise we
2160 * would read the new comm for the old pid.
2161 */
2162 pid = savedcmd->map_cmdline_to_pid[idx];
2163 if (pid != NO_CMDLINE_MAP)
2164 savedcmd->map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
2165
2166 savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
2167 savedcmd->map_pid_to_cmdline[tsk->pid] = idx;
2168
2169 savedcmd->cmdline_idx = idx;
2170 }
2171
2172 set_cmdline(idx, tsk->comm);
2173
2174 arch_spin_unlock(&trace_cmdline_lock);
2175
2176 return 1;
2177}
2178
2179static void __trace_find_cmdline(int pid, char comm[])
2180{
2181 unsigned map;
2182
2183 if (!pid) {
2184 strcpy(comm, "<idle>");
2185 return;
2186 }
2187
2188 if (WARN_ON_ONCE(pid < 0)) {
2189 strcpy(comm, "<XXX>");
2190 return;
2191 }
2192
2193 if (pid > PID_MAX_DEFAULT) {
2194 strcpy(comm, "<...>");
2195 return;
2196 }
2197
2198 map = savedcmd->map_pid_to_cmdline[pid];
2199 if (map != NO_CMDLINE_MAP)
2200 strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
2201 else
2202 strcpy(comm, "<...>");
2203}
2204
2205void trace_find_cmdline(int pid, char comm[])
2206{
2207 preempt_disable();
2208 arch_spin_lock(&trace_cmdline_lock);
2209
2210 __trace_find_cmdline(pid, comm);
2211
2212 arch_spin_unlock(&trace_cmdline_lock);
2213 preempt_enable();
2214}
2215
2216int trace_find_tgid(int pid)
2217{
2218 if (unlikely(!tgid_map || !pid || pid > PID_MAX_DEFAULT))
2219 return 0;
2220
2221 return tgid_map[pid];
2222}
2223
2224static int trace_save_tgid(struct task_struct *tsk)
2225{
2226 /* treat recording of idle task as a success */
2227 if (!tsk->pid)
2228 return 1;
2229
2230 if (unlikely(!tgid_map || tsk->pid > PID_MAX_DEFAULT))
2231 return 0;
2232
2233 tgid_map[tsk->pid] = tsk->tgid;
2234 return 1;
2235}
2236
2237static bool tracing_record_taskinfo_skip(int flags)
2238{
2239 if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID))))
2240 return true;
2241 if (atomic_read(&trace_record_taskinfo_disabled) || !tracing_is_on())
2242 return true;
2243 if (!__this_cpu_read(trace_taskinfo_save))
2244 return true;
2245 return false;
2246}
2247
2248/**
2249 * tracing_record_taskinfo - record the task info of a task
2250 *
2251 * @task: task to record
2252 * @flags: TRACE_RECORD_CMDLINE for recording comm
2253 * TRACE_RECORD_TGID for recording tgid
2254 */
2255void tracing_record_taskinfo(struct task_struct *task, int flags)
2256{
2257 bool done;
2258
2259 if (tracing_record_taskinfo_skip(flags))
2260 return;
2261
2262 /*
2263 * Record as much task information as possible. If some fail, continue
2264 * to try to record the others.
2265 */
2266 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task);
2267 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task);
2268
2269 /* If recording any information failed, retry again soon. */
2270 if (!done)
2271 return;
2272
2273 __this_cpu_write(trace_taskinfo_save, false);
2274}
2275
2276/**
2277 * tracing_record_taskinfo_sched_switch - record task info for sched_switch
2278 *
2279 * @prev: previous task during sched_switch
2280 * @next: next task during sched_switch
2281 * @flags: TRACE_RECORD_CMDLINE for recording comm
2282 * TRACE_RECORD_TGID for recording tgid
2283 */
2284void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
2285 struct task_struct *next, int flags)
2286{
2287 bool done;
2288
2289 if (tracing_record_taskinfo_skip(flags))
2290 return;
2291
2292 /*
2293 * Record as much task information as possible. If some fail, continue
2294 * to try to record the others.
2295 */
2296 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev);
2297 done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next);
2298 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev);
2299 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next);
2300
2301 /* If recording any information failed, retry again soon. */
2302 if (!done)
2303 return;
2304
2305 __this_cpu_write(trace_taskinfo_save, false);
2306}
2307
2308/* Helpers to record a specific task information */
2309void tracing_record_cmdline(struct task_struct *task)
2310{
2311 tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE);
2312}
2313
2314void tracing_record_tgid(struct task_struct *task)
2315{
2316 tracing_record_taskinfo(task, TRACE_RECORD_TGID);
2317}
2318
2319/*
2320 * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
2321 * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
2322 * simplifies those functions and keeps them in sync.
2323 */
2324enum print_line_t trace_handle_return(struct trace_seq *s)
2325{
2326 return trace_seq_has_overflowed(s) ?
2327 TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
2328}
2329EXPORT_SYMBOL_GPL(trace_handle_return);
2330
2331void
2332tracing_generic_entry_update(struct trace_entry *entry, unsigned short type,
2333 unsigned long flags, int pc)
2334{
2335 struct task_struct *tsk = current;
2336
2337 entry->preempt_count = pc & 0xff;
2338 entry->pid = (tsk) ? tsk->pid : 0;
2339 entry->type = type;
2340 entry->flags =
2341#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
2342 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
2343#else
2344 TRACE_FLAG_IRQS_NOSUPPORT |
2345#endif
2346 ((pc & NMI_MASK ) ? TRACE_FLAG_NMI : 0) |
2347 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
2348 ((pc & SOFTIRQ_OFFSET) ? TRACE_FLAG_SOFTIRQ : 0) |
2349 (tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
2350 (test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
2351}
2352EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
2353
2354struct ring_buffer_event *
2355trace_buffer_lock_reserve(struct ring_buffer *buffer,
2356 int type,
2357 unsigned long len,
2358 unsigned long flags, int pc)
2359{
2360 return __trace_buffer_lock_reserve(buffer, type, len, flags, pc);
2361}
2362
2363DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
2364DEFINE_PER_CPU(int, trace_buffered_event_cnt);
2365static int trace_buffered_event_ref;
2366
2367/**
2368 * trace_buffered_event_enable - enable buffering events
2369 *
2370 * When events are being filtered, it is quicker to use a temporary
2371 * buffer to write the event data into if there's a likely chance
2372 * that it will not be committed. The discard of the ring buffer
2373 * is not as fast as committing, and is much slower than copying
2374 * a commit.
2375 *
2376 * When an event is to be filtered, allocate per cpu buffers to
2377 * write the event data into, and if the event is filtered and discarded
2378 * it is simply dropped, otherwise, the entire data is to be committed
2379 * in one shot.
2380 */
2381void trace_buffered_event_enable(void)
2382{
2383 struct ring_buffer_event *event;
2384 struct page *page;
2385 int cpu;
2386
2387 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2388
2389 if (trace_buffered_event_ref++)
2390 return;
2391
2392 for_each_tracing_cpu(cpu) {
2393 page = alloc_pages_node(cpu_to_node(cpu),
2394 GFP_KERNEL | __GFP_NORETRY, 0);
2395 if (!page)
2396 goto failed;
2397
2398 event = page_address(page);
2399 memset(event, 0, sizeof(*event));
2400
2401 per_cpu(trace_buffered_event, cpu) = event;
2402
2403 preempt_disable();
2404 if (cpu == smp_processor_id() &&
2405 this_cpu_read(trace_buffered_event) !=
2406 per_cpu(trace_buffered_event, cpu))
2407 WARN_ON_ONCE(1);
2408 preempt_enable();
2409 }
2410
2411 return;
2412 failed:
2413 trace_buffered_event_disable();
2414}
2415
2416static void enable_trace_buffered_event(void *data)
2417{
2418 /* Probably not needed, but do it anyway */
2419 smp_rmb();
2420 this_cpu_dec(trace_buffered_event_cnt);
2421}
2422
2423static void disable_trace_buffered_event(void *data)
2424{
2425 this_cpu_inc(trace_buffered_event_cnt);
2426}
2427
2428/**
2429 * trace_buffered_event_disable - disable buffering events
2430 *
2431 * When a filter is removed, it is faster to not use the buffered
2432 * events, and to commit directly into the ring buffer. Free up
2433 * the temp buffers when there are no more users. This requires
2434 * special synchronization with current events.
2435 */
2436void trace_buffered_event_disable(void)
2437{
2438 int cpu;
2439
2440 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2441
2442 if (WARN_ON_ONCE(!trace_buffered_event_ref))
2443 return;
2444
2445 if (--trace_buffered_event_ref)
2446 return;
2447
2448 preempt_disable();
2449 /* For each CPU, set the buffer as used. */
2450 smp_call_function_many(tracing_buffer_mask,
2451 disable_trace_buffered_event, NULL, 1);
2452 preempt_enable();
2453
2454 /* Wait for all current users to finish */
2455 synchronize_rcu();
2456
2457 for_each_tracing_cpu(cpu) {
2458 free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
2459 per_cpu(trace_buffered_event, cpu) = NULL;
2460 }
2461 /*
2462 * Make sure trace_buffered_event is NULL before clearing
2463 * trace_buffered_event_cnt.
2464 */
2465 smp_wmb();
2466
2467 preempt_disable();
2468 /* Do the work on each cpu */
2469 smp_call_function_many(tracing_buffer_mask,
2470 enable_trace_buffered_event, NULL, 1);
2471 preempt_enable();
2472}
2473
2474static struct ring_buffer *temp_buffer;
2475
2476struct ring_buffer_event *
2477trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
2478 struct trace_event_file *trace_file,
2479 int type, unsigned long len,
2480 unsigned long flags, int pc)
2481{
2482 struct ring_buffer_event *entry;
2483 int val;
2484
2485 *current_rb = trace_file->tr->trace_buffer.buffer;
2486
2487 if (!ring_buffer_time_stamp_abs(*current_rb) && (trace_file->flags &
2488 (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
2489 (entry = this_cpu_read(trace_buffered_event))) {
2490 /* Try to use the per cpu buffer first */
2491 val = this_cpu_inc_return(trace_buffered_event_cnt);
2492 if (val == 1) {
2493 trace_event_setup(entry, type, flags, pc);
2494 entry->array[0] = len;
2495 return entry;
2496 }
2497 this_cpu_dec(trace_buffered_event_cnt);
2498 }
2499
2500 entry = __trace_buffer_lock_reserve(*current_rb,
2501 type, len, flags, pc);
2502 /*
2503 * If tracing is off, but we have triggers enabled
2504 * we still need to look at the event data. Use the temp_buffer
2505 * to store the trace event for the tigger to use. It's recusive
2506 * safe and will not be recorded anywhere.
2507 */
2508 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
2509 *current_rb = temp_buffer;
2510 entry = __trace_buffer_lock_reserve(*current_rb,
2511 type, len, flags, pc);
2512 }
2513 return entry;
2514}
2515EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
2516
2517static DEFINE_SPINLOCK(tracepoint_iter_lock);
2518static DEFINE_MUTEX(tracepoint_printk_mutex);
2519
2520static void output_printk(struct trace_event_buffer *fbuffer)
2521{
2522 struct trace_event_call *event_call;
2523 struct trace_event *event;
2524 unsigned long flags;
2525 struct trace_iterator *iter = tracepoint_print_iter;
2526
2527 /* We should never get here if iter is NULL */
2528 if (WARN_ON_ONCE(!iter))
2529 return;
2530
2531 event_call = fbuffer->trace_file->event_call;
2532 if (!event_call || !event_call->event.funcs ||
2533 !event_call->event.funcs->trace)
2534 return;
2535
2536 event = &fbuffer->trace_file->event_call->event;
2537
2538 spin_lock_irqsave(&tracepoint_iter_lock, flags);
2539 trace_seq_init(&iter->seq);
2540 iter->ent = fbuffer->entry;
2541 event_call->event.funcs->trace(iter, 0, event);
2542 trace_seq_putc(&iter->seq, 0);
2543 printk("%s", iter->seq.buffer);
2544
2545 spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
2546}
2547
2548int tracepoint_printk_sysctl(struct ctl_table *table, int write,
2549 void __user *buffer, size_t *lenp,
2550 loff_t *ppos)
2551{
2552 int save_tracepoint_printk;
2553 int ret;
2554
2555 mutex_lock(&tracepoint_printk_mutex);
2556 save_tracepoint_printk = tracepoint_printk;
2557
2558 ret = proc_dointvec(table, write, buffer, lenp, ppos);
2559
2560 /*
2561 * This will force exiting early, as tracepoint_printk
2562 * is always zero when tracepoint_printk_iter is not allocated
2563 */
2564 if (!tracepoint_print_iter)
2565 tracepoint_printk = 0;
2566
2567 if (save_tracepoint_printk == tracepoint_printk)
2568 goto out;
2569
2570 if (tracepoint_printk)
2571 static_key_enable(&tracepoint_printk_key.key);
2572 else
2573 static_key_disable(&tracepoint_printk_key.key);
2574
2575 out:
2576 mutex_unlock(&tracepoint_printk_mutex);
2577
2578 return ret;
2579}
2580
2581void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
2582{
2583 if (static_key_false(&tracepoint_printk_key.key))
2584 output_printk(fbuffer);
2585
2586 event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer,
2587 fbuffer->event, fbuffer->entry,
2588 fbuffer->flags, fbuffer->pc);
2589}
2590EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
2591
2592/*
2593 * Skip 3:
2594 *
2595 * trace_buffer_unlock_commit_regs()
2596 * trace_event_buffer_commit()
2597 * trace_event_raw_event_xxx()
2598 */
2599# define STACK_SKIP 3
2600
2601void trace_buffer_unlock_commit_regs(struct trace_array *tr,
2602 struct ring_buffer *buffer,
2603 struct ring_buffer_event *event,
2604 unsigned long flags, int pc,
2605 struct pt_regs *regs)
2606{
2607 __buffer_unlock_commit(buffer, event);
2608
2609 /*
2610 * If regs is not set, then skip the necessary functions.
2611 * Note, we can still get here via blktrace, wakeup tracer
2612 * and mmiotrace, but that's ok if they lose a function or
2613 * two. They are not that meaningful.
2614 */
2615 ftrace_trace_stack(tr, buffer, flags, regs ? 0 : STACK_SKIP, pc, regs);
2616 ftrace_trace_userstack(buffer, flags, pc);
2617}
2618
2619/*
2620 * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
2621 */
2622void
2623trace_buffer_unlock_commit_nostack(struct ring_buffer *buffer,
2624 struct ring_buffer_event *event)
2625{
2626 __buffer_unlock_commit(buffer, event);
2627}
2628
2629static void
2630trace_process_export(struct trace_export *export,
2631 struct ring_buffer_event *event)
2632{
2633 struct trace_entry *entry;
2634 unsigned int size = 0;
2635
2636 entry = ring_buffer_event_data(event);
2637 size = ring_buffer_event_length(event);
2638 export->write(export, entry, size);
2639}
2640
2641static DEFINE_MUTEX(ftrace_export_lock);
2642
2643static struct trace_export __rcu *ftrace_exports_list __read_mostly;
2644
2645static DEFINE_STATIC_KEY_FALSE(ftrace_exports_enabled);
2646
2647static inline void ftrace_exports_enable(void)
2648{
2649 static_branch_enable(&ftrace_exports_enabled);
2650}
2651
2652static inline void ftrace_exports_disable(void)
2653{
2654 static_branch_disable(&ftrace_exports_enabled);
2655}
2656
2657static void ftrace_exports(struct ring_buffer_event *event)
2658{
2659 struct trace_export *export;
2660
2661 preempt_disable_notrace();
2662
2663 export = rcu_dereference_raw_check(ftrace_exports_list);
2664 while (export) {
2665 trace_process_export(export, event);
2666 export = rcu_dereference_raw_check(export->next);
2667 }
2668
2669 preempt_enable_notrace();
2670}
2671
2672static inline void
2673add_trace_export(struct trace_export **list, struct trace_export *export)
2674{
2675 rcu_assign_pointer(export->next, *list);
2676 /*
2677 * We are entering export into the list but another
2678 * CPU might be walking that list. We need to make sure
2679 * the export->next pointer is valid before another CPU sees
2680 * the export pointer included into the list.
2681 */
2682 rcu_assign_pointer(*list, export);
2683}
2684
2685static inline int
2686rm_trace_export(struct trace_export **list, struct trace_export *export)
2687{
2688 struct trace_export **p;
2689
2690 for (p = list; *p != NULL; p = &(*p)->next)
2691 if (*p == export)
2692 break;
2693
2694 if (*p != export)
2695 return -1;
2696
2697 rcu_assign_pointer(*p, (*p)->next);
2698
2699 return 0;
2700}
2701
2702static inline void
2703add_ftrace_export(struct trace_export **list, struct trace_export *export)
2704{
2705 if (*list == NULL)
2706 ftrace_exports_enable();
2707
2708 add_trace_export(list, export);
2709}
2710
2711static inline int
2712rm_ftrace_export(struct trace_export **list, struct trace_export *export)
2713{
2714 int ret;
2715
2716 ret = rm_trace_export(list, export);
2717 if (*list == NULL)
2718 ftrace_exports_disable();
2719
2720 return ret;
2721}
2722
2723int register_ftrace_export(struct trace_export *export)
2724{
2725 if (WARN_ON_ONCE(!export->write))
2726 return -1;
2727
2728 mutex_lock(&ftrace_export_lock);
2729
2730 add_ftrace_export(&ftrace_exports_list, export);
2731
2732 mutex_unlock(&ftrace_export_lock);
2733
2734 return 0;
2735}
2736EXPORT_SYMBOL_GPL(register_ftrace_export);
2737
2738int unregister_ftrace_export(struct trace_export *export)
2739{
2740 int ret;
2741
2742 mutex_lock(&ftrace_export_lock);
2743
2744 ret = rm_ftrace_export(&ftrace_exports_list, export);
2745
2746 mutex_unlock(&ftrace_export_lock);
2747
2748 return ret;
2749}
2750EXPORT_SYMBOL_GPL(unregister_ftrace_export);
2751
2752void
2753trace_function(struct trace_array *tr,
2754 unsigned long ip, unsigned long parent_ip, unsigned long flags,
2755 int pc)
2756{
2757 struct trace_event_call *call = &event_function;
2758 struct ring_buffer *buffer = tr->trace_buffer.buffer;
2759 struct ring_buffer_event *event;
2760 struct ftrace_entry *entry;
2761
2762 event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
2763 flags, pc);
2764 if (!event)
2765 return;
2766 entry = ring_buffer_event_data(event);
2767 entry->ip = ip;
2768 entry->parent_ip = parent_ip;
2769
2770 if (!call_filter_check_discard(call, entry, buffer, event)) {
2771 if (static_branch_unlikely(&ftrace_exports_enabled))
2772 ftrace_exports(event);
2773 __buffer_unlock_commit(buffer, event);
2774 }
2775}
2776
2777#ifdef CONFIG_STACKTRACE
2778
2779/* Allow 4 levels of nesting: normal, softirq, irq, NMI */
2780#define FTRACE_KSTACK_NESTING 4
2781
2782#define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING)
2783
2784struct ftrace_stack {
2785 unsigned long calls[FTRACE_KSTACK_ENTRIES];
2786};
2787
2788
2789struct ftrace_stacks {
2790 struct ftrace_stack stacks[FTRACE_KSTACK_NESTING];
2791};
2792
2793static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
2794static DEFINE_PER_CPU(int, ftrace_stack_reserve);
2795
2796static void __ftrace_trace_stack(struct ring_buffer *buffer,
2797 unsigned long flags,
2798 int skip, int pc, struct pt_regs *regs)
2799{
2800 struct trace_event_call *call = &event_kernel_stack;
2801 struct ring_buffer_event *event;
2802 unsigned int size, nr_entries;
2803 struct ftrace_stack *fstack;
2804 struct stack_entry *entry;
2805 int stackidx;
2806
2807 /*
2808 * Add one, for this function and the call to save_stack_trace()
2809 * If regs is set, then these functions will not be in the way.
2810 */
2811#ifndef CONFIG_UNWINDER_ORC
2812 if (!regs)
2813 skip++;
2814#endif
2815
2816 /*
2817 * Since events can happen in NMIs there's no safe way to
2818 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
2819 * or NMI comes in, it will just have to use the default
2820 * FTRACE_STACK_SIZE.
2821 */
2822 preempt_disable_notrace();
2823
2824 stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
2825
2826 /* This should never happen. If it does, yell once and skip */
2827 if (WARN_ON_ONCE(stackidx > FTRACE_KSTACK_NESTING))
2828 goto out;
2829
2830 /*
2831 * The above __this_cpu_inc_return() is 'atomic' cpu local. An
2832 * interrupt will either see the value pre increment or post
2833 * increment. If the interrupt happens pre increment it will have
2834 * restored the counter when it returns. We just need a barrier to
2835 * keep gcc from moving things around.
2836 */
2837 barrier();
2838
2839 fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx;
2840 size = ARRAY_SIZE(fstack->calls);
2841
2842 if (regs) {
2843 nr_entries = stack_trace_save_regs(regs, fstack->calls,
2844 size, skip);
2845 } else {
2846 nr_entries = stack_trace_save(fstack->calls, size, skip);
2847 }
2848
2849 size = nr_entries * sizeof(unsigned long);
2850 event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
2851 sizeof(*entry) + size, flags, pc);
2852 if (!event)
2853 goto out;
2854 entry = ring_buffer_event_data(event);
2855
2856 memcpy(&entry->caller, fstack->calls, size);
2857 entry->size = nr_entries;
2858
2859 if (!call_filter_check_discard(call, entry, buffer, event))
2860 __buffer_unlock_commit(buffer, event);
2861
2862 out:
2863 /* Again, don't let gcc optimize things here */
2864 barrier();
2865 __this_cpu_dec(ftrace_stack_reserve);
2866 preempt_enable_notrace();
2867
2868}
2869
2870static inline void ftrace_trace_stack(struct trace_array *tr,
2871 struct ring_buffer *buffer,
2872 unsigned long flags,
2873 int skip, int pc, struct pt_regs *regs)
2874{
2875 if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
2876 return;
2877
2878 __ftrace_trace_stack(buffer, flags, skip, pc, regs);
2879}
2880
2881void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
2882 int pc)
2883{
2884 struct ring_buffer *buffer = tr->trace_buffer.buffer;
2885
2886 if (rcu_is_watching()) {
2887 __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
2888 return;
2889 }
2890
2891 /*
2892 * When an NMI triggers, RCU is enabled via rcu_nmi_enter(),
2893 * but if the above rcu_is_watching() failed, then the NMI
2894 * triggered someplace critical, and rcu_irq_enter() should
2895 * not be called from NMI.
2896 */
2897 if (unlikely(in_nmi()))
2898 return;
2899
2900 rcu_irq_enter_irqson();
2901 __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
2902 rcu_irq_exit_irqson();
2903}
2904
2905/**
2906 * trace_dump_stack - record a stack back trace in the trace buffer
2907 * @skip: Number of functions to skip (helper handlers)
2908 */
2909void trace_dump_stack(int skip)
2910{
2911 unsigned long flags;
2912
2913 if (tracing_disabled || tracing_selftest_running)
2914 return;
2915
2916 local_save_flags(flags);
2917
2918#ifndef CONFIG_UNWINDER_ORC
2919 /* Skip 1 to skip this function. */
2920 skip++;
2921#endif
2922 __ftrace_trace_stack(global_trace.trace_buffer.buffer,
2923 flags, skip, preempt_count(), NULL);
2924}
2925EXPORT_SYMBOL_GPL(trace_dump_stack);
2926
2927#ifdef CONFIG_USER_STACKTRACE_SUPPORT
2928static DEFINE_PER_CPU(int, user_stack_count);
2929
2930static void
2931ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
2932{
2933 struct trace_event_call *call = &event_user_stack;
2934 struct ring_buffer_event *event;
2935 struct userstack_entry *entry;
2936
2937 if (!(global_trace.trace_flags & TRACE_ITER_USERSTACKTRACE))
2938 return;
2939
2940 /*
2941 * NMIs can not handle page faults, even with fix ups.
2942 * The save user stack can (and often does) fault.
2943 */
2944 if (unlikely(in_nmi()))
2945 return;
2946
2947 /*
2948 * prevent recursion, since the user stack tracing may
2949 * trigger other kernel events.
2950 */
2951 preempt_disable();
2952 if (__this_cpu_read(user_stack_count))
2953 goto out;
2954
2955 __this_cpu_inc(user_stack_count);
2956
2957 event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
2958 sizeof(*entry), flags, pc);
2959 if (!event)
2960 goto out_drop_count;
2961 entry = ring_buffer_event_data(event);
2962
2963 entry->tgid = current->tgid;
2964 memset(&entry->caller, 0, sizeof(entry->caller));
2965
2966 stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES);
2967 if (!call_filter_check_discard(call, entry, buffer, event))
2968 __buffer_unlock_commit(buffer, event);
2969
2970 out_drop_count:
2971 __this_cpu_dec(user_stack_count);
2972 out:
2973 preempt_enable();
2974}
2975#else /* CONFIG_USER_STACKTRACE_SUPPORT */
2976static void ftrace_trace_userstack(struct ring_buffer *buffer,
2977 unsigned long flags, int pc)
2978{
2979}
2980#endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
2981
2982#endif /* CONFIG_STACKTRACE */
2983
2984/* created for use with alloc_percpu */
2985struct trace_buffer_struct {
2986 int nesting;
2987 char buffer[4][TRACE_BUF_SIZE];
2988};
2989
2990static struct trace_buffer_struct *trace_percpu_buffer;
2991
2992/*
2993 * Thise allows for lockless recording. If we're nested too deeply, then
2994 * this returns NULL.
2995 */
2996static char *get_trace_buf(void)
2997{
2998 struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
2999
3000 if (!buffer || buffer->nesting >= 4)
3001 return NULL;
3002
3003 buffer->nesting++;
3004
3005 /* Interrupts must see nesting incremented before we use the buffer */
3006 barrier();
3007 return &buffer->buffer[buffer->nesting][0];
3008}
3009
3010static void put_trace_buf(void)
3011{
3012 /* Don't let the decrement of nesting leak before this */
3013 barrier();
3014 this_cpu_dec(trace_percpu_buffer->nesting);
3015}
3016
3017static int alloc_percpu_trace_buffer(void)
3018{
3019 struct trace_buffer_struct *buffers;
3020
3021 buffers = alloc_percpu(struct trace_buffer_struct);
3022 if (WARN(!buffers, "Could not allocate percpu trace_printk buffer"))
3023 return -ENOMEM;
3024
3025 trace_percpu_buffer = buffers;
3026 return 0;
3027}
3028
3029static int buffers_allocated;
3030
3031void trace_printk_init_buffers(void)
3032{
3033 if (buffers_allocated)
3034 return;
3035
3036 if (alloc_percpu_trace_buffer())
3037 return;
3038
3039 /* trace_printk() is for debug use only. Don't use it in production. */
3040
3041 pr_warn("\n");
3042 pr_warn("**********************************************************\n");
3043 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3044 pr_warn("** **\n");
3045 pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
3046 pr_warn("** **\n");
3047 pr_warn("** This means that this is a DEBUG kernel and it is **\n");
3048 pr_warn("** unsafe for production use. **\n");
3049 pr_warn("** **\n");
3050 pr_warn("** If you see this message and you are not debugging **\n");
3051 pr_warn("** the kernel, report this immediately to your vendor! **\n");
3052 pr_warn("** **\n");
3053 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3054 pr_warn("**********************************************************\n");
3055
3056 /* Expand the buffers to set size */
3057 tracing_update_buffers();
3058
3059 buffers_allocated = 1;
3060
3061 /*
3062 * trace_printk_init_buffers() can be called by modules.
3063 * If that happens, then we need to start cmdline recording
3064 * directly here. If the global_trace.buffer is already
3065 * allocated here, then this was called by module code.
3066 */
3067 if (global_trace.trace_buffer.buffer)
3068 tracing_start_cmdline_record();
3069}
3070EXPORT_SYMBOL_GPL(trace_printk_init_buffers);
3071
3072void trace_printk_start_comm(void)
3073{
3074 /* Start tracing comms if trace printk is set */
3075 if (!buffers_allocated)
3076 return;
3077 tracing_start_cmdline_record();
3078}
3079
3080static void trace_printk_start_stop_comm(int enabled)
3081{
3082 if (!buffers_allocated)
3083 return;
3084
3085 if (enabled)
3086 tracing_start_cmdline_record();
3087 else
3088 tracing_stop_cmdline_record();
3089}
3090
3091/**
3092 * trace_vbprintk - write binary msg to tracing buffer
3093 * @ip: The address of the caller
3094 * @fmt: The string format to write to the buffer
3095 * @args: Arguments for @fmt
3096 */
3097int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
3098{
3099 struct trace_event_call *call = &event_bprint;
3100 struct ring_buffer_event *event;
3101 struct ring_buffer *buffer;
3102 struct trace_array *tr = &global_trace;
3103 struct bprint_entry *entry;
3104 unsigned long flags;
3105 char *tbuffer;
3106 int len = 0, size, pc;
3107
3108 if (unlikely(tracing_selftest_running || tracing_disabled))
3109 return 0;
3110
3111 /* Don't pollute graph traces with trace_vprintk internals */
3112 pause_graph_tracing();
3113
3114 pc = preempt_count();
3115 preempt_disable_notrace();
3116
3117 tbuffer = get_trace_buf();
3118 if (!tbuffer) {
3119 len = 0;
3120 goto out_nobuffer;
3121 }
3122
3123 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
3124
3125 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
3126 goto out;
3127
3128 local_save_flags(flags);
3129 size = sizeof(*entry) + sizeof(u32) * len;
3130 buffer = tr->trace_buffer.buffer;
3131 event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
3132 flags, pc);
3133 if (!event)
3134 goto out;
3135 entry = ring_buffer_event_data(event);
3136 entry->ip = ip;
3137 entry->fmt = fmt;
3138
3139 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
3140 if (!call_filter_check_discard(call, entry, buffer, event)) {
3141 __buffer_unlock_commit(buffer, event);
3142 ftrace_trace_stack(tr, buffer, flags, 6, pc, NULL);
3143 }
3144
3145out:
3146 put_trace_buf();
3147
3148out_nobuffer:
3149 preempt_enable_notrace();
3150 unpause_graph_tracing();
3151
3152 return len;
3153}
3154EXPORT_SYMBOL_GPL(trace_vbprintk);
3155
3156__printf(3, 0)
3157static int
3158__trace_array_vprintk(struct ring_buffer *buffer,
3159 unsigned long ip, const char *fmt, va_list args)
3160{
3161 struct trace_event_call *call = &event_print;
3162 struct ring_buffer_event *event;
3163 int len = 0, size, pc;
3164 struct print_entry *entry;
3165 unsigned long flags;
3166 char *tbuffer;
3167
3168 if (tracing_disabled || tracing_selftest_running)
3169 return 0;
3170
3171 /* Don't pollute graph traces with trace_vprintk internals */
3172 pause_graph_tracing();
3173
3174 pc = preempt_count();
3175 preempt_disable_notrace();
3176
3177
3178 tbuffer = get_trace_buf();
3179 if (!tbuffer) {
3180 len = 0;
3181 goto out_nobuffer;
3182 }
3183
3184 len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
3185
3186 local_save_flags(flags);
3187 size = sizeof(*entry) + len + 1;
3188 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3189 flags, pc);
3190 if (!event)
3191 goto out;
3192 entry = ring_buffer_event_data(event);
3193 entry->ip = ip;
3194
3195 memcpy(&entry->buf, tbuffer, len + 1);
3196 if (!call_filter_check_discard(call, entry, buffer, event)) {
3197 __buffer_unlock_commit(buffer, event);
3198 ftrace_trace_stack(&global_trace, buffer, flags, 6, pc, NULL);
3199 }
3200
3201out:
3202 put_trace_buf();
3203
3204out_nobuffer:
3205 preempt_enable_notrace();
3206 unpause_graph_tracing();
3207
3208 return len;
3209}
3210
3211__printf(3, 0)
3212int trace_array_vprintk(struct trace_array *tr,
3213 unsigned long ip, const char *fmt, va_list args)
3214{
3215 return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
3216}
3217
3218__printf(3, 0)
3219int trace_array_printk(struct trace_array *tr,
3220 unsigned long ip, const char *fmt, ...)
3221{
3222 int ret;
3223 va_list ap;
3224
3225 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
3226 return 0;
3227
3228 va_start(ap, fmt);
3229 ret = trace_array_vprintk(tr, ip, fmt, ap);
3230 va_end(ap);
3231 return ret;
3232}
3233EXPORT_SYMBOL_GPL(trace_array_printk);
3234
3235__printf(3, 4)
3236int trace_array_printk_buf(struct ring_buffer *buffer,
3237 unsigned long ip, const char *fmt, ...)
3238{
3239 int ret;
3240 va_list ap;
3241
3242 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
3243 return 0;
3244
3245 va_start(ap, fmt);
3246 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
3247 va_end(ap);
3248 return ret;
3249}
3250
3251__printf(2, 0)
3252int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3253{
3254 return trace_array_vprintk(&global_trace, ip, fmt, args);
3255}
3256EXPORT_SYMBOL_GPL(trace_vprintk);
3257
3258static void trace_iterator_increment(struct trace_iterator *iter)
3259{
3260 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
3261
3262 iter->idx++;
3263 if (buf_iter)
3264 ring_buffer_read(buf_iter, NULL);
3265}
3266
3267static struct trace_entry *
3268peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
3269 unsigned long *lost_events)
3270{
3271 struct ring_buffer_event *event;
3272 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
3273
3274 if (buf_iter)
3275 event = ring_buffer_iter_peek(buf_iter, ts);
3276 else
3277 event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts,
3278 lost_events);
3279
3280 if (event) {
3281 iter->ent_size = ring_buffer_event_length(event);
3282 return ring_buffer_event_data(event);
3283 }
3284 iter->ent_size = 0;
3285 return NULL;
3286}
3287
3288static struct trace_entry *
3289__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
3290 unsigned long *missing_events, u64 *ent_ts)
3291{
3292 struct ring_buffer *buffer = iter->trace_buffer->buffer;
3293 struct trace_entry *ent, *next = NULL;
3294 unsigned long lost_events = 0, next_lost = 0;
3295 int cpu_file = iter->cpu_file;
3296 u64 next_ts = 0, ts;
3297 int next_cpu = -1;
3298 int next_size = 0;
3299 int cpu;
3300
3301 /*
3302 * If we are in a per_cpu trace file, don't bother by iterating over
3303 * all cpu and peek directly.
3304 */
3305 if (cpu_file > RING_BUFFER_ALL_CPUS) {
3306 if (ring_buffer_empty_cpu(buffer, cpu_file))
3307 return NULL;
3308 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
3309 if (ent_cpu)
3310 *ent_cpu = cpu_file;
3311
3312 return ent;
3313 }
3314
3315 for_each_tracing_cpu(cpu) {
3316
3317 if (ring_buffer_empty_cpu(buffer, cpu))
3318 continue;
3319
3320 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
3321
3322 /*
3323 * Pick the entry with the smallest timestamp:
3324 */
3325 if (ent && (!next || ts < next_ts)) {
3326 next = ent;
3327 next_cpu = cpu;
3328 next_ts = ts;
3329 next_lost = lost_events;
3330 next_size = iter->ent_size;
3331 }
3332 }
3333
3334 iter->ent_size = next_size;
3335
3336 if (ent_cpu)
3337 *ent_cpu = next_cpu;
3338
3339 if (ent_ts)
3340 *ent_ts = next_ts;
3341
3342 if (missing_events)
3343 *missing_events = next_lost;
3344
3345 return next;
3346}
3347
3348/* Find the next real entry, without updating the iterator itself */
3349struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
3350 int *ent_cpu, u64 *ent_ts)
3351{
3352 return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
3353}
3354
3355/* Find the next real entry, and increment the iterator to the next entry */
3356void *trace_find_next_entry_inc(struct trace_iterator *iter)
3357{
3358 iter->ent = __find_next_entry(iter, &iter->cpu,
3359 &iter->lost_events, &iter->ts);
3360
3361 if (iter->ent)
3362 trace_iterator_increment(iter);
3363
3364 return iter->ent ? iter : NULL;
3365}
3366
3367static void trace_consume(struct trace_iterator *iter)
3368{
3369 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts,
3370 &iter->lost_events);
3371}
3372
3373static void *s_next(struct seq_file *m, void *v, loff_t *pos)
3374{
3375 struct trace_iterator *iter = m->private;
3376 int i = (int)*pos;
3377 void *ent;
3378
3379 WARN_ON_ONCE(iter->leftover);
3380
3381 (*pos)++;
3382
3383 /* can't go backwards */
3384 if (iter->idx > i)
3385 return NULL;
3386
3387 if (iter->idx < 0)
3388 ent = trace_find_next_entry_inc(iter);
3389 else
3390 ent = iter;
3391
3392 while (ent && iter->idx < i)
3393 ent = trace_find_next_entry_inc(iter);
3394
3395 iter->pos = *pos;
3396
3397 return ent;
3398}
3399
3400void tracing_iter_reset(struct trace_iterator *iter, int cpu)
3401{
3402 struct ring_buffer_event *event;
3403 struct ring_buffer_iter *buf_iter;
3404 unsigned long entries = 0;
3405 u64 ts;
3406
3407 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0;
3408
3409 buf_iter = trace_buffer_iter(iter, cpu);
3410 if (!buf_iter)
3411 return;
3412
3413 ring_buffer_iter_reset(buf_iter);
3414
3415 /*
3416 * We could have the case with the max latency tracers
3417 * that a reset never took place on a cpu. This is evident
3418 * by the timestamp being before the start of the buffer.
3419 */
3420 while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
3421 if (ts >= iter->trace_buffer->time_start)
3422 break;
3423 entries++;
3424 ring_buffer_read(buf_iter, NULL);
3425 }
3426
3427 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries;
3428}
3429
3430/*
3431 * The current tracer is copied to avoid a global locking
3432 * all around.
3433 */
3434static void *s_start(struct seq_file *m, loff_t *pos)
3435{
3436 struct trace_iterator *iter = m->private;
3437 struct trace_array *tr = iter->tr;
3438 int cpu_file = iter->cpu_file;
3439 void *p = NULL;
3440 loff_t l = 0;
3441 int cpu;
3442
3443 /*
3444 * copy the tracer to avoid using a global lock all around.
3445 * iter->trace is a copy of current_trace, the pointer to the
3446 * name may be used instead of a strcmp(), as iter->trace->name
3447 * will point to the same string as current_trace->name.
3448 */
3449 mutex_lock(&trace_types_lock);
3450 if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
3451 *iter->trace = *tr->current_trace;
3452 mutex_unlock(&trace_types_lock);
3453
3454#ifdef CONFIG_TRACER_MAX_TRACE
3455 if (iter->snapshot && iter->trace->use_max_tr)
3456 return ERR_PTR(-EBUSY);
3457#endif
3458
3459 if (!iter->snapshot)
3460 atomic_inc(&trace_record_taskinfo_disabled);
3461
3462 if (*pos != iter->pos) {
3463 iter->ent = NULL;
3464 iter->cpu = 0;
3465 iter->idx = -1;
3466
3467 if (cpu_file == RING_BUFFER_ALL_CPUS) {
3468 for_each_tracing_cpu(cpu)
3469 tracing_iter_reset(iter, cpu);
3470 } else
3471 tracing_iter_reset(iter, cpu_file);
3472
3473 iter->leftover = 0;
3474 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
3475 ;
3476
3477 } else {
3478 /*
3479 * If we overflowed the seq_file before, then we want
3480 * to just reuse the trace_seq buffer again.
3481 */
3482 if (iter->leftover)
3483 p = iter;
3484 else {
3485 l = *pos - 1;
3486 p = s_next(m, p, &l);
3487 }
3488 }
3489
3490 trace_event_read_lock();
3491 trace_access_lock(cpu_file);
3492 return p;
3493}
3494
3495static void s_stop(struct seq_file *m, void *p)
3496{
3497 struct trace_iterator *iter = m->private;
3498
3499#ifdef CONFIG_TRACER_MAX_TRACE
3500 if (iter->snapshot && iter->trace->use_max_tr)
3501 return;
3502#endif
3503
3504 if (!iter->snapshot)
3505 atomic_dec(&trace_record_taskinfo_disabled);
3506
3507 trace_access_unlock(iter->cpu_file);
3508 trace_event_read_unlock();
3509}
3510
3511static void
3512get_total_entries_cpu(struct trace_buffer *buf, unsigned long *total,
3513 unsigned long *entries, int cpu)
3514{
3515 unsigned long count;
3516
3517 count = ring_buffer_entries_cpu(buf->buffer, cpu);
3518 /*
3519 * If this buffer has skipped entries, then we hold all
3520 * entries for the trace and we need to ignore the
3521 * ones before the time stamp.
3522 */
3523 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
3524 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
3525 /* total is the same as the entries */
3526 *total = count;
3527 } else
3528 *total = count +
3529 ring_buffer_overrun_cpu(buf->buffer, cpu);
3530 *entries = count;
3531}
3532
3533static void
3534get_total_entries(struct trace_buffer *buf,
3535 unsigned long *total, unsigned long *entries)
3536{
3537 unsigned long t, e;
3538 int cpu;
3539
3540 *total = 0;
3541 *entries = 0;
3542
3543 for_each_tracing_cpu(cpu) {
3544 get_total_entries_cpu(buf, &t, &e, cpu);
3545 *total += t;
3546 *entries += e;
3547 }
3548}
3549
3550unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
3551{
3552 unsigned long total, entries;
3553
3554 if (!tr)
3555 tr = &global_trace;
3556
3557 get_total_entries_cpu(&tr->trace_buffer, &total, &entries, cpu);
3558
3559 return entries;
3560}
3561
3562unsigned long trace_total_entries(struct trace_array *tr)
3563{
3564 unsigned long total, entries;
3565
3566 if (!tr)
3567 tr = &global_trace;
3568
3569 get_total_entries(&tr->trace_buffer, &total, &entries);
3570
3571 return entries;
3572}
3573
3574static void print_lat_help_header(struct seq_file *m)
3575{
3576 seq_puts(m, "# _------=> CPU# \n"
3577 "# / _-----=> irqs-off \n"
3578 "# | / _----=> need-resched \n"
3579 "# || / _---=> hardirq/softirq \n"
3580 "# ||| / _--=> preempt-depth \n"
3581 "# |||| / delay \n"
3582 "# cmd pid ||||| time | caller \n"
3583 "# \\ / ||||| \\ | / \n");
3584}
3585
3586static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
3587{
3588 unsigned long total;
3589 unsigned long entries;
3590
3591 get_total_entries(buf, &total, &entries);
3592 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
3593 entries, total, num_online_cpus());
3594 seq_puts(m, "#\n");
3595}
3596
3597static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m,
3598 unsigned int flags)
3599{
3600 bool tgid = flags & TRACE_ITER_RECORD_TGID;
3601
3602 print_event_info(buf, m);
3603
3604 seq_printf(m, "# TASK-PID %s CPU# TIMESTAMP FUNCTION\n", tgid ? "TGID " : "");
3605 seq_printf(m, "# | | %s | | |\n", tgid ? " | " : "");
3606}
3607
3608static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m,
3609 unsigned int flags)
3610{
3611 bool tgid = flags & TRACE_ITER_RECORD_TGID;
3612 const char *space = " ";
3613 int prec = tgid ? 10 : 2;
3614
3615 print_event_info(buf, m);
3616
3617 seq_printf(m, "# %.*s _-----=> irqs-off\n", prec, space);
3618 seq_printf(m, "# %.*s / _----=> need-resched\n", prec, space);
3619 seq_printf(m, "# %.*s| / _---=> hardirq/softirq\n", prec, space);
3620 seq_printf(m, "# %.*s|| / _--=> preempt-depth\n", prec, space);
3621 seq_printf(m, "# %.*s||| / delay\n", prec, space);
3622 seq_printf(m, "# TASK-PID %.*sCPU# |||| TIMESTAMP FUNCTION\n", prec, " TGID ");
3623 seq_printf(m, "# | | %.*s | |||| | |\n", prec, " | ");
3624}
3625
3626void
3627print_trace_header(struct seq_file *m, struct trace_iterator *iter)
3628{
3629 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
3630 struct trace_buffer *buf = iter->trace_buffer;
3631 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
3632 struct tracer *type = iter->trace;
3633 unsigned long entries;
3634 unsigned long total;
3635 const char *name = "preemption";
3636
3637 name = type->name;
3638
3639 get_total_entries(buf, &total, &entries);
3640
3641 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
3642 name, UTS_RELEASE);
3643 seq_puts(m, "# -----------------------------------"
3644 "---------------------------------\n");
3645 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
3646 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
3647 nsecs_to_usecs(data->saved_latency),
3648 entries,
3649 total,
3650 buf->cpu,
3651#if defined(CONFIG_PREEMPT_NONE)
3652 "server",
3653#elif defined(CONFIG_PREEMPT_VOLUNTARY)
3654 "desktop",
3655#elif defined(CONFIG_PREEMPT)
3656 "preempt",
3657#else
3658 "unknown",
3659#endif
3660 /* These are reserved for later use */
3661 0, 0, 0, 0);
3662#ifdef CONFIG_SMP
3663 seq_printf(m, " #P:%d)\n", num_online_cpus());
3664#else
3665 seq_puts(m, ")\n");
3666#endif
3667 seq_puts(m, "# -----------------\n");
3668 seq_printf(m, "# | task: %.16s-%d "
3669 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
3670 data->comm, data->pid,
3671 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
3672 data->policy, data->rt_priority);
3673 seq_puts(m, "# -----------------\n");
3674
3675 if (data->critical_start) {
3676 seq_puts(m, "# => started at: ");
3677 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
3678 trace_print_seq(m, &iter->seq);
3679 seq_puts(m, "\n# => ended at: ");
3680 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
3681 trace_print_seq(m, &iter->seq);
3682 seq_puts(m, "\n#\n");
3683 }
3684
3685 seq_puts(m, "#\n");
3686}
3687
3688static void test_cpu_buff_start(struct trace_iterator *iter)
3689{
3690 struct trace_seq *s = &iter->seq;
3691 struct trace_array *tr = iter->tr;
3692
3693 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
3694 return;
3695
3696 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
3697 return;
3698
3699 if (cpumask_available(iter->started) &&
3700 cpumask_test_cpu(iter->cpu, iter->started))
3701 return;
3702
3703 if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries)
3704 return;
3705
3706 if (cpumask_available(iter->started))
3707 cpumask_set_cpu(iter->cpu, iter->started);
3708
3709 /* Don't print started cpu buffer for the first entry of the trace */
3710 if (iter->idx > 1)
3711 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
3712 iter->cpu);
3713}
3714
3715static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
3716{
3717 struct trace_array *tr = iter->tr;
3718 struct trace_seq *s = &iter->seq;
3719 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
3720 struct trace_entry *entry;
3721 struct trace_event *event;
3722
3723 entry = iter->ent;
3724
3725 test_cpu_buff_start(iter);
3726
3727 event = ftrace_find_event(entry->type);
3728
3729 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3730 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
3731 trace_print_lat_context(iter);
3732 else
3733 trace_print_context(iter);
3734 }
3735
3736 if (trace_seq_has_overflowed(s))
3737 return TRACE_TYPE_PARTIAL_LINE;
3738
3739 if (event)
3740 return event->funcs->trace(iter, sym_flags, event);
3741
3742 trace_seq_printf(s, "Unknown type %d\n", entry->type);
3743
3744 return trace_handle_return(s);
3745}
3746
3747static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
3748{
3749 struct trace_array *tr = iter->tr;
3750 struct trace_seq *s = &iter->seq;
3751 struct trace_entry *entry;
3752 struct trace_event *event;
3753
3754 entry = iter->ent;
3755
3756 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
3757 trace_seq_printf(s, "%d %d %llu ",
3758 entry->pid, iter->cpu, iter->ts);
3759
3760 if (trace_seq_has_overflowed(s))
3761 return TRACE_TYPE_PARTIAL_LINE;
3762
3763 event = ftrace_find_event(entry->type);
3764 if (event)
3765 return event->funcs->raw(iter, 0, event);
3766
3767 trace_seq_printf(s, "%d ?\n", entry->type);
3768
3769 return trace_handle_return(s);
3770}
3771
3772static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
3773{
3774 struct trace_array *tr = iter->tr;
3775 struct trace_seq *s = &iter->seq;
3776 unsigned char newline = '\n';
3777 struct trace_entry *entry;
3778 struct trace_event *event;
3779
3780 entry = iter->ent;
3781
3782 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3783 SEQ_PUT_HEX_FIELD(s, entry->pid);
3784 SEQ_PUT_HEX_FIELD(s, iter->cpu);
3785 SEQ_PUT_HEX_FIELD(s, iter->ts);
3786 if (trace_seq_has_overflowed(s))
3787 return TRACE_TYPE_PARTIAL_LINE;
3788 }
3789
3790 event = ftrace_find_event(entry->type);
3791 if (event) {
3792 enum print_line_t ret = event->funcs->hex(iter, 0, event);
3793 if (ret != TRACE_TYPE_HANDLED)
3794 return ret;
3795 }
3796
3797 SEQ_PUT_FIELD(s, newline);
3798
3799 return trace_handle_return(s);
3800}
3801
3802static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
3803{
3804 struct trace_array *tr = iter->tr;
3805 struct trace_seq *s = &iter->seq;
3806 struct trace_entry *entry;
3807 struct trace_event *event;
3808
3809 entry = iter->ent;
3810
3811 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3812 SEQ_PUT_FIELD(s, entry->pid);
3813 SEQ_PUT_FIELD(s, iter->cpu);
3814 SEQ_PUT_FIELD(s, iter->ts);
3815 if (trace_seq_has_overflowed(s))
3816 return TRACE_TYPE_PARTIAL_LINE;
3817 }
3818
3819 event = ftrace_find_event(entry->type);
3820 return event ? event->funcs->binary(iter, 0, event) :
3821 TRACE_TYPE_HANDLED;
3822}
3823
3824int trace_empty(struct trace_iterator *iter)
3825{
3826 struct ring_buffer_iter *buf_iter;
3827 int cpu;
3828
3829 /* If we are looking at one CPU buffer, only check that one */
3830 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
3831 cpu = iter->cpu_file;
3832 buf_iter = trace_buffer_iter(iter, cpu);
3833 if (buf_iter) {
3834 if (!ring_buffer_iter_empty(buf_iter))
3835 return 0;
3836 } else {
3837 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
3838 return 0;
3839 }
3840 return 1;
3841 }
3842
3843 for_each_tracing_cpu(cpu) {
3844 buf_iter = trace_buffer_iter(iter, cpu);
3845 if (buf_iter) {
3846 if (!ring_buffer_iter_empty(buf_iter))
3847 return 0;
3848 } else {
3849 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
3850 return 0;
3851 }
3852 }
3853
3854 return 1;
3855}
3856
3857/* Called with trace_event_read_lock() held. */
3858enum print_line_t print_trace_line(struct trace_iterator *iter)
3859{
3860 struct trace_array *tr = iter->tr;
3861 unsigned long trace_flags = tr->trace_flags;
3862 enum print_line_t ret;
3863
3864 if (iter->lost_events) {
3865 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
3866 iter->cpu, iter->lost_events);
3867 if (trace_seq_has_overflowed(&iter->seq))
3868 return TRACE_TYPE_PARTIAL_LINE;
3869 }
3870
3871 if (iter->trace && iter->trace->print_line) {
3872 ret = iter->trace->print_line(iter);
3873 if (ret != TRACE_TYPE_UNHANDLED)
3874 return ret;
3875 }
3876
3877 if (iter->ent->type == TRACE_BPUTS &&
3878 trace_flags & TRACE_ITER_PRINTK &&
3879 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3880 return trace_print_bputs_msg_only(iter);
3881
3882 if (iter->ent->type == TRACE_BPRINT &&
3883 trace_flags & TRACE_ITER_PRINTK &&
3884 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3885 return trace_print_bprintk_msg_only(iter);
3886
3887 if (iter->ent->type == TRACE_PRINT &&
3888 trace_flags & TRACE_ITER_PRINTK &&
3889 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3890 return trace_print_printk_msg_only(iter);
3891
3892 if (trace_flags & TRACE_ITER_BIN)
3893 return print_bin_fmt(iter);
3894
3895 if (trace_flags & TRACE_ITER_HEX)
3896 return print_hex_fmt(iter);
3897
3898 if (trace_flags & TRACE_ITER_RAW)
3899 return print_raw_fmt(iter);
3900
3901 return print_trace_fmt(iter);
3902}
3903
3904void trace_latency_header(struct seq_file *m)
3905{
3906 struct trace_iterator *iter = m->private;
3907 struct trace_array *tr = iter->tr;
3908
3909 /* print nothing if the buffers are empty */
3910 if (trace_empty(iter))
3911 return;
3912
3913 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
3914 print_trace_header(m, iter);
3915
3916 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
3917 print_lat_help_header(m);
3918}
3919
3920void trace_default_header(struct seq_file *m)
3921{
3922 struct trace_iterator *iter = m->private;
3923 struct trace_array *tr = iter->tr;
3924 unsigned long trace_flags = tr->trace_flags;
3925
3926 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
3927 return;
3928
3929 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
3930 /* print nothing if the buffers are empty */
3931 if (trace_empty(iter))
3932 return;
3933 print_trace_header(m, iter);
3934 if (!(trace_flags & TRACE_ITER_VERBOSE))
3935 print_lat_help_header(m);
3936 } else {
3937 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
3938 if (trace_flags & TRACE_ITER_IRQ_INFO)
3939 print_func_help_header_irq(iter->trace_buffer,
3940 m, trace_flags);
3941 else
3942 print_func_help_header(iter->trace_buffer, m,
3943 trace_flags);
3944 }
3945 }
3946}
3947
3948static void test_ftrace_alive(struct seq_file *m)
3949{
3950 if (!ftrace_is_dead())
3951 return;
3952 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
3953 "# MAY BE MISSING FUNCTION EVENTS\n");
3954}
3955
3956#ifdef CONFIG_TRACER_MAX_TRACE
3957static void show_snapshot_main_help(struct seq_file *m)
3958{
3959 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
3960 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
3961 "# Takes a snapshot of the main buffer.\n"
3962 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
3963 "# (Doesn't have to be '2' works with any number that\n"
3964 "# is not a '0' or '1')\n");
3965}
3966
3967static void show_snapshot_percpu_help(struct seq_file *m)
3968{
3969 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
3970#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
3971 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
3972 "# Takes a snapshot of the main buffer for this cpu.\n");
3973#else
3974 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
3975 "# Must use main snapshot file to allocate.\n");
3976#endif
3977 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
3978 "# (Doesn't have to be '2' works with any number that\n"
3979 "# is not a '0' or '1')\n");
3980}
3981
3982static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
3983{
3984 if (iter->tr->allocated_snapshot)
3985 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
3986 else
3987 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
3988
3989 seq_puts(m, "# Snapshot commands:\n");
3990 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
3991 show_snapshot_main_help(m);
3992 else
3993 show_snapshot_percpu_help(m);
3994}
3995#else
3996/* Should never be called */
3997static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
3998#endif
3999
4000static int s_show(struct seq_file *m, void *v)
4001{
4002 struct trace_iterator *iter = v;
4003 int ret;
4004
4005 if (iter->ent == NULL) {
4006 if (iter->tr) {
4007 seq_printf(m, "# tracer: %s\n", iter->trace->name);
4008 seq_puts(m, "#\n");
4009 test_ftrace_alive(m);
4010 }
4011 if (iter->snapshot && trace_empty(iter))
4012 print_snapshot_help(m, iter);
4013 else if (iter->trace && iter->trace->print_header)
4014 iter->trace->print_header(m);
4015 else
4016 trace_default_header(m);
4017
4018 } else if (iter->leftover) {
4019 /*
4020 * If we filled the seq_file buffer earlier, we
4021 * want to just show it now.
4022 */
4023 ret = trace_print_seq(m, &iter->seq);
4024
4025 /* ret should this time be zero, but you never know */
4026 iter->leftover = ret;
4027
4028 } else {
4029 print_trace_line(iter);
4030 ret = trace_print_seq(m, &iter->seq);
4031 /*
4032 * If we overflow the seq_file buffer, then it will
4033 * ask us for this data again at start up.
4034 * Use that instead.
4035 * ret is 0 if seq_file write succeeded.
4036 * -1 otherwise.
4037 */
4038 iter->leftover = ret;
4039 }
4040
4041 return 0;
4042}
4043
4044/*
4045 * Should be used after trace_array_get(), trace_types_lock
4046 * ensures that i_cdev was already initialized.
4047 */
4048static inline int tracing_get_cpu(struct inode *inode)
4049{
4050 if (inode->i_cdev) /* See trace_create_cpu_file() */
4051 return (long)inode->i_cdev - 1;
4052 return RING_BUFFER_ALL_CPUS;
4053}
4054
4055static const struct seq_operations tracer_seq_ops = {
4056 .start = s_start,
4057 .next = s_next,
4058 .stop = s_stop,
4059 .show = s_show,
4060};
4061
4062static struct trace_iterator *
4063__tracing_open(struct inode *inode, struct file *file, bool snapshot)
4064{
4065 struct trace_array *tr = inode->i_private;
4066 struct trace_iterator *iter;
4067 int cpu;
4068
4069 if (tracing_disabled)
4070 return ERR_PTR(-ENODEV);
4071
4072 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
4073 if (!iter)
4074 return ERR_PTR(-ENOMEM);
4075
4076 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
4077 GFP_KERNEL);
4078 if (!iter->buffer_iter)
4079 goto release;
4080
4081 /*
4082 * We make a copy of the current tracer to avoid concurrent
4083 * changes on it while we are reading.
4084 */
4085 mutex_lock(&trace_types_lock);
4086 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
4087 if (!iter->trace)
4088 goto fail;
4089
4090 *iter->trace = *tr->current_trace;
4091
4092 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
4093 goto fail;
4094
4095 iter->tr = tr;
4096
4097#ifdef CONFIG_TRACER_MAX_TRACE
4098 /* Currently only the top directory has a snapshot */
4099 if (tr->current_trace->print_max || snapshot)
4100 iter->trace_buffer = &tr->max_buffer;
4101 else
4102#endif
4103 iter->trace_buffer = &tr->trace_buffer;
4104 iter->snapshot = snapshot;
4105 iter->pos = -1;
4106 iter->cpu_file = tracing_get_cpu(inode);
4107 mutex_init(&iter->mutex);
4108
4109 /* Notify the tracer early; before we stop tracing. */
4110 if (iter->trace && iter->trace->open)
4111 iter->trace->open(iter);
4112
4113 /* Annotate start of buffers if we had overruns */
4114 if (ring_buffer_overruns(iter->trace_buffer->buffer))
4115 iter->iter_flags |= TRACE_FILE_ANNOTATE;
4116
4117 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4118 if (trace_clocks[tr->clock_id].in_ns)
4119 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4120
4121 /* stop the trace while dumping if we are not opening "snapshot" */
4122 if (!iter->snapshot)
4123 tracing_stop_tr(tr);
4124
4125 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
4126 for_each_tracing_cpu(cpu) {
4127 iter->buffer_iter[cpu] =
4128 ring_buffer_read_prepare(iter->trace_buffer->buffer,
4129 cpu, GFP_KERNEL);
4130 }
4131 ring_buffer_read_prepare_sync();
4132 for_each_tracing_cpu(cpu) {
4133 ring_buffer_read_start(iter->buffer_iter[cpu]);
4134 tracing_iter_reset(iter, cpu);
4135 }
4136 } else {
4137 cpu = iter->cpu_file;
4138 iter->buffer_iter[cpu] =
4139 ring_buffer_read_prepare(iter->trace_buffer->buffer,
4140 cpu, GFP_KERNEL);
4141 ring_buffer_read_prepare_sync();
4142 ring_buffer_read_start(iter->buffer_iter[cpu]);
4143 tracing_iter_reset(iter, cpu);
4144 }
4145
4146 mutex_unlock(&trace_types_lock);
4147
4148 return iter;
4149
4150 fail:
4151 mutex_unlock(&trace_types_lock);
4152 kfree(iter->trace);
4153 kfree(iter->buffer_iter);
4154release:
4155 seq_release_private(inode, file);
4156 return ERR_PTR(-ENOMEM);
4157}
4158
4159int tracing_open_generic(struct inode *inode, struct file *filp)
4160{
4161 int ret;
4162
4163 ret = tracing_check_open_get_tr(NULL);
4164 if (ret)
4165 return ret;
4166
4167 filp->private_data = inode->i_private;
4168 return 0;
4169}
4170
4171bool tracing_is_disabled(void)
4172{
4173 return (tracing_disabled) ? true: false;
4174}
4175
4176/*
4177 * Open and update trace_array ref count.
4178 * Must have the current trace_array passed to it.
4179 */
4180int tracing_open_generic_tr(struct inode *inode, struct file *filp)
4181{
4182 struct trace_array *tr = inode->i_private;
4183 int ret;
4184
4185 ret = tracing_check_open_get_tr(tr);
4186 if (ret)
4187 return ret;
4188
4189 filp->private_data = inode->i_private;
4190
4191 return 0;
4192}
4193
4194static int tracing_release(struct inode *inode, struct file *file)
4195{
4196 struct trace_array *tr = inode->i_private;
4197 struct seq_file *m = file->private_data;
4198 struct trace_iterator *iter;
4199 int cpu;
4200
4201 if (!(file->f_mode & FMODE_READ)) {
4202 trace_array_put(tr);
4203 return 0;
4204 }
4205
4206 /* Writes do not use seq_file */
4207 iter = m->private;
4208 mutex_lock(&trace_types_lock);
4209
4210 for_each_tracing_cpu(cpu) {
4211 if (iter->buffer_iter[cpu])
4212 ring_buffer_read_finish(iter->buffer_iter[cpu]);
4213 }
4214
4215 if (iter->trace && iter->trace->close)
4216 iter->trace->close(iter);
4217
4218 if (!iter->snapshot)
4219 /* reenable tracing if it was previously enabled */
4220 tracing_start_tr(tr);
4221
4222 __trace_array_put(tr);
4223
4224 mutex_unlock(&trace_types_lock);
4225
4226 mutex_destroy(&iter->mutex);
4227 free_cpumask_var(iter->started);
4228 kfree(iter->trace);
4229 kfree(iter->buffer_iter);
4230 seq_release_private(inode, file);
4231
4232 return 0;
4233}
4234
4235static int tracing_release_generic_tr(struct inode *inode, struct file *file)
4236{
4237 struct trace_array *tr = inode->i_private;
4238
4239 trace_array_put(tr);
4240 return 0;
4241}
4242
4243static int tracing_single_release_tr(struct inode *inode, struct file *file)
4244{
4245 struct trace_array *tr = inode->i_private;
4246
4247 trace_array_put(tr);
4248
4249 return single_release(inode, file);
4250}
4251
4252static int tracing_open(struct inode *inode, struct file *file)
4253{
4254 struct trace_array *tr = inode->i_private;
4255 struct trace_iterator *iter;
4256 int ret;
4257
4258 ret = tracing_check_open_get_tr(tr);
4259 if (ret)
4260 return ret;
4261
4262 /* If this file was open for write, then erase contents */
4263 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
4264 int cpu = tracing_get_cpu(inode);
4265 struct trace_buffer *trace_buf = &tr->trace_buffer;
4266
4267#ifdef CONFIG_TRACER_MAX_TRACE
4268 if (tr->current_trace->print_max)
4269 trace_buf = &tr->max_buffer;
4270#endif
4271
4272 if (cpu == RING_BUFFER_ALL_CPUS)
4273 tracing_reset_online_cpus(trace_buf);
4274 else
4275 tracing_reset_cpu(trace_buf, cpu);
4276 }
4277
4278 if (file->f_mode & FMODE_READ) {
4279 iter = __tracing_open(inode, file, false);
4280 if (IS_ERR(iter))
4281 ret = PTR_ERR(iter);
4282 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
4283 iter->iter_flags |= TRACE_FILE_LAT_FMT;
4284 }
4285
4286 if (ret < 0)
4287 trace_array_put(tr);
4288
4289 return ret;
4290}
4291
4292/*
4293 * Some tracers are not suitable for instance buffers.
4294 * A tracer is always available for the global array (toplevel)
4295 * or if it explicitly states that it is.
4296 */
4297static bool
4298trace_ok_for_array(struct tracer *t, struct trace_array *tr)
4299{
4300 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
4301}
4302
4303/* Find the next tracer that this trace array may use */
4304static struct tracer *
4305get_tracer_for_array(struct trace_array *tr, struct tracer *t)
4306{
4307 while (t && !trace_ok_for_array(t, tr))
4308 t = t->next;
4309
4310 return t;
4311}
4312
4313static void *
4314t_next(struct seq_file *m, void *v, loff_t *pos)
4315{
4316 struct trace_array *tr = m->private;
4317 struct tracer *t = v;
4318
4319 (*pos)++;
4320
4321 if (t)
4322 t = get_tracer_for_array(tr, t->next);
4323
4324 return t;
4325}
4326
4327static void *t_start(struct seq_file *m, loff_t *pos)
4328{
4329 struct trace_array *tr = m->private;
4330 struct tracer *t;
4331 loff_t l = 0;
4332
4333 mutex_lock(&trace_types_lock);
4334
4335 t = get_tracer_for_array(tr, trace_types);
4336 for (; t && l < *pos; t = t_next(m, t, &l))
4337 ;
4338
4339 return t;
4340}
4341
4342static void t_stop(struct seq_file *m, void *p)
4343{
4344 mutex_unlock(&trace_types_lock);
4345}
4346
4347static int t_show(struct seq_file *m, void *v)
4348{
4349 struct tracer *t = v;
4350
4351 if (!t)
4352 return 0;
4353
4354 seq_puts(m, t->name);
4355 if (t->next)
4356 seq_putc(m, ' ');
4357 else
4358 seq_putc(m, '\n');
4359
4360 return 0;
4361}
4362
4363static const struct seq_operations show_traces_seq_ops = {
4364 .start = t_start,
4365 .next = t_next,
4366 .stop = t_stop,
4367 .show = t_show,
4368};
4369
4370static int show_traces_open(struct inode *inode, struct file *file)
4371{
4372 struct trace_array *tr = inode->i_private;
4373 struct seq_file *m;
4374 int ret;
4375
4376 ret = tracing_check_open_get_tr(tr);
4377 if (ret)
4378 return ret;
4379
4380 ret = seq_open(file, &show_traces_seq_ops);
4381 if (ret) {
4382 trace_array_put(tr);
4383 return ret;
4384 }
4385
4386 m = file->private_data;
4387 m->private = tr;
4388
4389 return 0;
4390}
4391
4392static int show_traces_release(struct inode *inode, struct file *file)
4393{
4394 struct trace_array *tr = inode->i_private;
4395
4396 trace_array_put(tr);
4397 return seq_release(inode, file);
4398}
4399
4400static ssize_t
4401tracing_write_stub(struct file *filp, const char __user *ubuf,
4402 size_t count, loff_t *ppos)
4403{
4404 return count;
4405}
4406
4407loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
4408{
4409 int ret;
4410
4411 if (file->f_mode & FMODE_READ)
4412 ret = seq_lseek(file, offset, whence);
4413 else
4414 file->f_pos = ret = 0;
4415
4416 return ret;
4417}
4418
4419static const struct file_operations tracing_fops = {
4420 .open = tracing_open,
4421 .read = seq_read,
4422 .write = tracing_write_stub,
4423 .llseek = tracing_lseek,
4424 .release = tracing_release,
4425};
4426
4427static const struct file_operations show_traces_fops = {
4428 .open = show_traces_open,
4429 .read = seq_read,
4430 .llseek = seq_lseek,
4431 .release = show_traces_release,
4432};
4433
4434static ssize_t
4435tracing_cpumask_read(struct file *filp, char __user *ubuf,
4436 size_t count, loff_t *ppos)
4437{
4438 struct trace_array *tr = file_inode(filp)->i_private;
4439 char *mask_str;
4440 int len;
4441
4442 len = snprintf(NULL, 0, "%*pb\n",
4443 cpumask_pr_args(tr->tracing_cpumask)) + 1;
4444 mask_str = kmalloc(len, GFP_KERNEL);
4445 if (!mask_str)
4446 return -ENOMEM;
4447
4448 len = snprintf(mask_str, len, "%*pb\n",
4449 cpumask_pr_args(tr->tracing_cpumask));
4450 if (len >= count) {
4451 count = -EINVAL;
4452 goto out_err;
4453 }
4454 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
4455
4456out_err:
4457 kfree(mask_str);
4458
4459 return count;
4460}
4461
4462static ssize_t
4463tracing_cpumask_write(struct file *filp, const char __user *ubuf,
4464 size_t count, loff_t *ppos)
4465{
4466 struct trace_array *tr = file_inode(filp)->i_private;
4467 cpumask_var_t tracing_cpumask_new;
4468 int err, cpu;
4469
4470 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
4471 return -ENOMEM;
4472
4473 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
4474 if (err)
4475 goto err_unlock;
4476
4477 local_irq_disable();
4478 arch_spin_lock(&tr->max_lock);
4479 for_each_tracing_cpu(cpu) {
4480 /*
4481 * Increase/decrease the disabled counter if we are
4482 * about to flip a bit in the cpumask:
4483 */
4484 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
4485 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
4486 atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
4487 ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);
4488 }
4489 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
4490 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
4491 atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
4492 ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
4493 }
4494 }
4495 arch_spin_unlock(&tr->max_lock);
4496 local_irq_enable();
4497
4498 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
4499 free_cpumask_var(tracing_cpumask_new);
4500
4501 return count;
4502
4503err_unlock:
4504 free_cpumask_var(tracing_cpumask_new);
4505
4506 return err;
4507}
4508
4509static const struct file_operations tracing_cpumask_fops = {
4510 .open = tracing_open_generic_tr,
4511 .read = tracing_cpumask_read,
4512 .write = tracing_cpumask_write,
4513 .release = tracing_release_generic_tr,
4514 .llseek = generic_file_llseek,
4515};
4516
4517static int tracing_trace_options_show(struct seq_file *m, void *v)
4518{
4519 struct tracer_opt *trace_opts;
4520 struct trace_array *tr = m->private;
4521 u32 tracer_flags;
4522 int i;
4523
4524 mutex_lock(&trace_types_lock);
4525 tracer_flags = tr->current_trace->flags->val;
4526 trace_opts = tr->current_trace->flags->opts;
4527
4528 for (i = 0; trace_options[i]; i++) {
4529 if (tr->trace_flags & (1 << i))
4530 seq_printf(m, "%s\n", trace_options[i]);
4531 else
4532 seq_printf(m, "no%s\n", trace_options[i]);
4533 }
4534
4535 for (i = 0; trace_opts[i].name; i++) {
4536 if (tracer_flags & trace_opts[i].bit)
4537 seq_printf(m, "%s\n", trace_opts[i].name);
4538 else
4539 seq_printf(m, "no%s\n", trace_opts[i].name);
4540 }
4541 mutex_unlock(&trace_types_lock);
4542
4543 return 0;
4544}
4545
4546static int __set_tracer_option(struct trace_array *tr,
4547 struct tracer_flags *tracer_flags,
4548 struct tracer_opt *opts, int neg)
4549{
4550 struct tracer *trace = tracer_flags->trace;
4551 int ret;
4552
4553 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
4554 if (ret)
4555 return ret;
4556
4557 if (neg)
4558 tracer_flags->val &= ~opts->bit;
4559 else
4560 tracer_flags->val |= opts->bit;
4561 return 0;
4562}
4563
4564/* Try to assign a tracer specific option */
4565static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
4566{
4567 struct tracer *trace = tr->current_trace;
4568 struct tracer_flags *tracer_flags = trace->flags;
4569 struct tracer_opt *opts = NULL;
4570 int i;
4571
4572 for (i = 0; tracer_flags->opts[i].name; i++) {
4573 opts = &tracer_flags->opts[i];
4574
4575 if (strcmp(cmp, opts->name) == 0)
4576 return __set_tracer_option(tr, trace->flags, opts, neg);
4577 }
4578
4579 return -EINVAL;
4580}
4581
4582/* Some tracers require overwrite to stay enabled */
4583int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
4584{
4585 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
4586 return -1;
4587
4588 return 0;
4589}
4590
4591int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
4592{
4593 /* do nothing if flag is already set */
4594 if (!!(tr->trace_flags & mask) == !!enabled)
4595 return 0;
4596
4597 /* Give the tracer a chance to approve the change */
4598 if (tr->current_trace->flag_changed)
4599 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
4600 return -EINVAL;
4601
4602 if (enabled)
4603 tr->trace_flags |= mask;
4604 else
4605 tr->trace_flags &= ~mask;
4606
4607 if (mask == TRACE_ITER_RECORD_CMD)
4608 trace_event_enable_cmd_record(enabled);
4609
4610 if (mask == TRACE_ITER_RECORD_TGID) {
4611 if (!tgid_map)
4612 tgid_map = kcalloc(PID_MAX_DEFAULT + 1,
4613 sizeof(*tgid_map),
4614 GFP_KERNEL);
4615 if (!tgid_map) {
4616 tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
4617 return -ENOMEM;
4618 }
4619
4620 trace_event_enable_tgid_record(enabled);
4621 }
4622
4623 if (mask == TRACE_ITER_EVENT_FORK)
4624 trace_event_follow_fork(tr, enabled);
4625
4626 if (mask == TRACE_ITER_FUNC_FORK)
4627 ftrace_pid_follow_fork(tr, enabled);
4628
4629 if (mask == TRACE_ITER_OVERWRITE) {
4630 ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled);
4631#ifdef CONFIG_TRACER_MAX_TRACE
4632 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
4633#endif
4634 }
4635
4636 if (mask == TRACE_ITER_PRINTK) {
4637 trace_printk_start_stop_comm(enabled);
4638 trace_printk_control(enabled);
4639 }
4640
4641 return 0;
4642}
4643
4644static int trace_set_options(struct trace_array *tr, char *option)
4645{
4646 char *cmp;
4647 int neg = 0;
4648 int ret;
4649 size_t orig_len = strlen(option);
4650 int len;
4651
4652 cmp = strstrip(option);
4653
4654 len = str_has_prefix(cmp, "no");
4655 if (len)
4656 neg = 1;
4657
4658 cmp += len;
4659
4660 mutex_lock(&trace_types_lock);
4661
4662 ret = match_string(trace_options, -1, cmp);
4663 /* If no option could be set, test the specific tracer options */
4664 if (ret < 0)
4665 ret = set_tracer_option(tr, cmp, neg);
4666 else
4667 ret = set_tracer_flag(tr, 1 << ret, !neg);
4668
4669 mutex_unlock(&trace_types_lock);
4670
4671 /*
4672 * If the first trailing whitespace is replaced with '\0' by strstrip,
4673 * turn it back into a space.
4674 */
4675 if (orig_len > strlen(option))
4676 option[strlen(option)] = ' ';
4677
4678 return ret;
4679}
4680
4681static void __init apply_trace_boot_options(void)
4682{
4683 char *buf = trace_boot_options_buf;
4684 char *option;
4685
4686 while (true) {
4687 option = strsep(&buf, ",");
4688
4689 if (!option)
4690 break;
4691
4692 if (*option)
4693 trace_set_options(&global_trace, option);
4694
4695 /* Put back the comma to allow this to be called again */
4696 if (buf)
4697 *(buf - 1) = ',';
4698 }
4699}
4700
4701static ssize_t
4702tracing_trace_options_write(struct file *filp, const char __user *ubuf,
4703 size_t cnt, loff_t *ppos)
4704{
4705 struct seq_file *m = filp->private_data;
4706 struct trace_array *tr = m->private;
4707 char buf[64];
4708 int ret;
4709
4710 if (cnt >= sizeof(buf))
4711 return -EINVAL;
4712
4713 if (copy_from_user(buf, ubuf, cnt))
4714 return -EFAULT;
4715
4716 buf[cnt] = 0;
4717
4718 ret = trace_set_options(tr, buf);
4719 if (ret < 0)
4720 return ret;
4721
4722 *ppos += cnt;
4723
4724 return cnt;
4725}
4726
4727static int tracing_trace_options_open(struct inode *inode, struct file *file)
4728{
4729 struct trace_array *tr = inode->i_private;
4730 int ret;
4731
4732 ret = tracing_check_open_get_tr(tr);
4733 if (ret)
4734 return ret;
4735
4736 ret = single_open(file, tracing_trace_options_show, inode->i_private);
4737 if (ret < 0)
4738 trace_array_put(tr);
4739
4740 return ret;
4741}
4742
4743static const struct file_operations tracing_iter_fops = {
4744 .open = tracing_trace_options_open,
4745 .read = seq_read,
4746 .llseek = seq_lseek,
4747 .release = tracing_single_release_tr,
4748 .write = tracing_trace_options_write,
4749};
4750
4751static const char readme_msg[] =
4752 "tracing mini-HOWTO:\n\n"
4753 "# echo 0 > tracing_on : quick way to disable tracing\n"
4754 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
4755 " Important files:\n"
4756 " trace\t\t\t- The static contents of the buffer\n"
4757 "\t\t\t To clear the buffer write into this file: echo > trace\n"
4758 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
4759 " current_tracer\t- function and latency tracers\n"
4760 " available_tracers\t- list of configured tracers for current_tracer\n"
4761 " error_log\t- error log for failed commands (that support it)\n"
4762 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
4763 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
4764 " trace_clock\t\t-change the clock used to order events\n"
4765 " local: Per cpu clock but may not be synced across CPUs\n"
4766 " global: Synced across CPUs but slows tracing down.\n"
4767 " counter: Not a clock, but just an increment\n"
4768 " uptime: Jiffy counter from time of boot\n"
4769 " perf: Same clock that perf events use\n"
4770#ifdef CONFIG_X86_64
4771 " x86-tsc: TSC cycle counter\n"
4772#endif
4773 "\n timestamp_mode\t-view the mode used to timestamp events\n"
4774 " delta: Delta difference against a buffer-wide timestamp\n"
4775 " absolute: Absolute (standalone) timestamp\n"
4776 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
4777 "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
4778 " tracing_cpumask\t- Limit which CPUs to trace\n"
4779 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
4780 "\t\t\t Remove sub-buffer with rmdir\n"
4781 " trace_options\t\t- Set format or modify how tracing happens\n"
4782 "\t\t\t Disable an option by prefixing 'no' to the\n"
4783 "\t\t\t option name\n"
4784 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
4785#ifdef CONFIG_DYNAMIC_FTRACE
4786 "\n available_filter_functions - list of functions that can be filtered on\n"
4787 " set_ftrace_filter\t- echo function name in here to only trace these\n"
4788 "\t\t\t functions\n"
4789 "\t accepts: func_full_name or glob-matching-pattern\n"
4790 "\t modules: Can select a group via module\n"
4791 "\t Format: :mod:<module-name>\n"
4792 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
4793 "\t triggers: a command to perform when function is hit\n"
4794 "\t Format: <function>:<trigger>[:count]\n"
4795 "\t trigger: traceon, traceoff\n"
4796 "\t\t enable_event:<system>:<event>\n"
4797 "\t\t disable_event:<system>:<event>\n"
4798#ifdef CONFIG_STACKTRACE
4799 "\t\t stacktrace\n"
4800#endif
4801#ifdef CONFIG_TRACER_SNAPSHOT
4802 "\t\t snapshot\n"
4803#endif
4804 "\t\t dump\n"
4805 "\t\t cpudump\n"
4806 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
4807 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
4808 "\t The first one will disable tracing every time do_fault is hit\n"
4809 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
4810 "\t The first time do trap is hit and it disables tracing, the\n"
4811 "\t counter will decrement to 2. If tracing is already disabled,\n"
4812 "\t the counter will not decrement. It only decrements when the\n"
4813 "\t trigger did work\n"
4814 "\t To remove trigger without count:\n"
4815 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
4816 "\t To remove trigger with a count:\n"
4817 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
4818 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
4819 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
4820 "\t modules: Can select a group via module command :mod:\n"
4821 "\t Does not accept triggers\n"
4822#endif /* CONFIG_DYNAMIC_FTRACE */
4823#ifdef CONFIG_FUNCTION_TRACER
4824 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
4825 "\t\t (function)\n"
4826#endif
4827#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4828 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
4829 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
4830 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
4831#endif
4832#ifdef CONFIG_TRACER_SNAPSHOT
4833 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
4834 "\t\t\t snapshot buffer. Read the contents for more\n"
4835 "\t\t\t information\n"
4836#endif
4837#ifdef CONFIG_STACK_TRACER
4838 " stack_trace\t\t- Shows the max stack trace when active\n"
4839 " stack_max_size\t- Shows current max stack size that was traced\n"
4840 "\t\t\t Write into this file to reset the max size (trigger a\n"
4841 "\t\t\t new trace)\n"
4842#ifdef CONFIG_DYNAMIC_FTRACE
4843 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
4844 "\t\t\t traces\n"
4845#endif
4846#endif /* CONFIG_STACK_TRACER */
4847#ifdef CONFIG_DYNAMIC_EVENTS
4848 " dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
4849 "\t\t\t Write into this file to define/undefine new trace events.\n"
4850#endif
4851#ifdef CONFIG_KPROBE_EVENTS
4852 " kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
4853 "\t\t\t Write into this file to define/undefine new trace events.\n"
4854#endif
4855#ifdef CONFIG_UPROBE_EVENTS
4856 " uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
4857 "\t\t\t Write into this file to define/undefine new trace events.\n"
4858#endif
4859#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
4860 "\t accepts: event-definitions (one definition per line)\n"
4861 "\t Format: p[:[<group>/]<event>] <place> [<args>]\n"
4862 "\t r[maxactive][:[<group>/]<event>] <place> [<args>]\n"
4863#ifdef CONFIG_HIST_TRIGGERS
4864 "\t s:[synthetic/]<event> <field> [<field>]\n"
4865#endif
4866 "\t -:[<group>/]<event>\n"
4867#ifdef CONFIG_KPROBE_EVENTS
4868 "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
4869 "place (kretprobe): [<module>:]<symbol>[+<offset>]|<memaddr>\n"
4870#endif
4871#ifdef CONFIG_UPROBE_EVENTS
4872 " place (uprobe): <path>:<offset>[(ref_ctr_offset)]\n"
4873#endif
4874 "\t args: <name>=fetcharg[:type]\n"
4875 "\t fetcharg: %<register>, @<address>, @<symbol>[+|-<offset>],\n"
4876#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
4877 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
4878#else
4879 "\t $stack<index>, $stack, $retval, $comm,\n"
4880#endif
4881 "\t +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
4882 "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
4883 "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
4884 "\t <type>\\[<array-size>\\]\n"
4885#ifdef CONFIG_HIST_TRIGGERS
4886 "\t field: <stype> <name>;\n"
4887 "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
4888 "\t [unsigned] char/int/long\n"
4889#endif
4890#endif
4891 " events/\t\t- Directory containing all trace event subsystems:\n"
4892 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
4893 " events/<system>/\t- Directory containing all trace events for <system>:\n"
4894 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
4895 "\t\t\t events\n"
4896 " filter\t\t- If set, only events passing filter are traced\n"
4897 " events/<system>/<event>/\t- Directory containing control files for\n"
4898 "\t\t\t <event>:\n"
4899 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
4900 " filter\t\t- If set, only events passing filter are traced\n"
4901 " trigger\t\t- If set, a command to perform when event is hit\n"
4902 "\t Format: <trigger>[:count][if <filter>]\n"
4903 "\t trigger: traceon, traceoff\n"
4904 "\t enable_event:<system>:<event>\n"
4905 "\t disable_event:<system>:<event>\n"
4906#ifdef CONFIG_HIST_TRIGGERS
4907 "\t enable_hist:<system>:<event>\n"
4908 "\t disable_hist:<system>:<event>\n"
4909#endif
4910#ifdef CONFIG_STACKTRACE
4911 "\t\t stacktrace\n"
4912#endif
4913#ifdef CONFIG_TRACER_SNAPSHOT
4914 "\t\t snapshot\n"
4915#endif
4916#ifdef CONFIG_HIST_TRIGGERS
4917 "\t\t hist (see below)\n"
4918#endif
4919 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
4920 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
4921 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
4922 "\t events/block/block_unplug/trigger\n"
4923 "\t The first disables tracing every time block_unplug is hit.\n"
4924 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
4925 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
4926 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
4927 "\t Like function triggers, the counter is only decremented if it\n"
4928 "\t enabled or disabled tracing.\n"
4929 "\t To remove a trigger without a count:\n"
4930 "\t echo '!<trigger> > <system>/<event>/trigger\n"
4931 "\t To remove a trigger with a count:\n"
4932 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
4933 "\t Filters can be ignored when removing a trigger.\n"
4934#ifdef CONFIG_HIST_TRIGGERS
4935 " hist trigger\t- If set, event hits are aggregated into a hash table\n"
4936 "\t Format: hist:keys=<field1[,field2,...]>\n"
4937 "\t [:values=<field1[,field2,...]>]\n"
4938 "\t [:sort=<field1[,field2,...]>]\n"
4939 "\t [:size=#entries]\n"
4940 "\t [:pause][:continue][:clear]\n"
4941 "\t [:name=histname1]\n"
4942 "\t [:<handler>.<action>]\n"
4943 "\t [if <filter>]\n\n"
4944 "\t When a matching event is hit, an entry is added to a hash\n"
4945 "\t table using the key(s) and value(s) named, and the value of a\n"
4946 "\t sum called 'hitcount' is incremented. Keys and values\n"
4947 "\t correspond to fields in the event's format description. Keys\n"
4948 "\t can be any field, or the special string 'stacktrace'.\n"
4949 "\t Compound keys consisting of up to two fields can be specified\n"
4950 "\t by the 'keys' keyword. Values must correspond to numeric\n"
4951 "\t fields. Sort keys consisting of up to two fields can be\n"
4952 "\t specified using the 'sort' keyword. The sort direction can\n"
4953 "\t be modified by appending '.descending' or '.ascending' to a\n"
4954 "\t sort field. The 'size' parameter can be used to specify more\n"
4955 "\t or fewer than the default 2048 entries for the hashtable size.\n"
4956 "\t If a hist trigger is given a name using the 'name' parameter,\n"
4957 "\t its histogram data will be shared with other triggers of the\n"
4958 "\t same name, and trigger hits will update this common data.\n\n"
4959 "\t Reading the 'hist' file for the event will dump the hash\n"
4960 "\t table in its entirety to stdout. If there are multiple hist\n"
4961 "\t triggers attached to an event, there will be a table for each\n"
4962 "\t trigger in the output. The table displayed for a named\n"
4963 "\t trigger will be the same as any other instance having the\n"
4964 "\t same name. The default format used to display a given field\n"
4965 "\t can be modified by appending any of the following modifiers\n"
4966 "\t to the field name, as applicable:\n\n"
4967 "\t .hex display a number as a hex value\n"
4968 "\t .sym display an address as a symbol\n"
4969 "\t .sym-offset display an address as a symbol and offset\n"
4970 "\t .execname display a common_pid as a program name\n"
4971 "\t .syscall display a syscall id as a syscall name\n"
4972 "\t .log2 display log2 value rather than raw number\n"
4973 "\t .usecs display a common_timestamp in microseconds\n\n"
4974 "\t The 'pause' parameter can be used to pause an existing hist\n"
4975 "\t trigger or to start a hist trigger but not log any events\n"
4976 "\t until told to do so. 'continue' can be used to start or\n"
4977 "\t restart a paused hist trigger.\n\n"
4978 "\t The 'clear' parameter will clear the contents of a running\n"
4979 "\t hist trigger and leave its current paused/active state\n"
4980 "\t unchanged.\n\n"
4981 "\t The enable_hist and disable_hist triggers can be used to\n"
4982 "\t have one event conditionally start and stop another event's\n"
4983 "\t already-attached hist trigger. The syntax is analogous to\n"
4984 "\t the enable_event and disable_event triggers.\n\n"
4985 "\t Hist trigger handlers and actions are executed whenever a\n"
4986 "\t a histogram entry is added or updated. They take the form:\n\n"
4987 "\t <handler>.<action>\n\n"
4988 "\t The available handlers are:\n\n"
4989 "\t onmatch(matching.event) - invoke on addition or update\n"
4990 "\t onmax(var) - invoke if var exceeds current max\n"
4991 "\t onchange(var) - invoke action if var changes\n\n"
4992 "\t The available actions are:\n\n"
4993 "\t trace(<synthetic_event>,param list) - generate synthetic event\n"
4994 "\t save(field,...) - save current event fields\n"
4995#ifdef CONFIG_TRACER_SNAPSHOT
4996 "\t snapshot() - snapshot the trace buffer\n"
4997#endif
4998#endif
4999;
5000
5001static ssize_t
5002tracing_readme_read(struct file *filp, char __user *ubuf,
5003 size_t cnt, loff_t *ppos)
5004{
5005 return simple_read_from_buffer(ubuf, cnt, ppos,
5006 readme_msg, strlen(readme_msg));
5007}
5008
5009static const struct file_operations tracing_readme_fops = {
5010 .open = tracing_open_generic,
5011 .read = tracing_readme_read,
5012 .llseek = generic_file_llseek,
5013};
5014
5015static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
5016{
5017 int *ptr = v;
5018
5019 if (*pos || m->count)
5020 ptr++;
5021
5022 (*pos)++;
5023
5024 for (; ptr <= &tgid_map[PID_MAX_DEFAULT]; ptr++) {
5025 if (trace_find_tgid(*ptr))
5026 return ptr;
5027 }
5028
5029 return NULL;
5030}
5031
5032static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
5033{
5034 void *v;
5035 loff_t l = 0;
5036
5037 if (!tgid_map)
5038 return NULL;
5039
5040 v = &tgid_map[0];
5041 while (l <= *pos) {
5042 v = saved_tgids_next(m, v, &l);
5043 if (!v)
5044 return NULL;
5045 }
5046
5047 return v;
5048}
5049
5050static void saved_tgids_stop(struct seq_file *m, void *v)
5051{
5052}
5053
5054static int saved_tgids_show(struct seq_file *m, void *v)
5055{
5056 int pid = (int *)v - tgid_map;
5057
5058 seq_printf(m, "%d %d\n", pid, trace_find_tgid(pid));
5059 return 0;
5060}
5061
5062static const struct seq_operations tracing_saved_tgids_seq_ops = {
5063 .start = saved_tgids_start,
5064 .stop = saved_tgids_stop,
5065 .next = saved_tgids_next,
5066 .show = saved_tgids_show,
5067};
5068
5069static int tracing_saved_tgids_open(struct inode *inode, struct file *filp)
5070{
5071 int ret;
5072
5073 ret = tracing_check_open_get_tr(NULL);
5074 if (ret)
5075 return ret;
5076
5077 return seq_open(filp, &tracing_saved_tgids_seq_ops);
5078}
5079
5080
5081static const struct file_operations tracing_saved_tgids_fops = {
5082 .open = tracing_saved_tgids_open,
5083 .read = seq_read,
5084 .llseek = seq_lseek,
5085 .release = seq_release,
5086};
5087
5088static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
5089{
5090 unsigned int *ptr = v;
5091
5092 if (*pos || m->count)
5093 ptr++;
5094
5095 (*pos)++;
5096
5097 for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
5098 ptr++) {
5099 if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
5100 continue;
5101
5102 return ptr;
5103 }
5104
5105 return NULL;
5106}
5107
5108static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
5109{
5110 void *v;
5111 loff_t l = 0;
5112
5113 preempt_disable();
5114 arch_spin_lock(&trace_cmdline_lock);
5115
5116 v = &savedcmd->map_cmdline_to_pid[0];
5117 while (l <= *pos) {
5118 v = saved_cmdlines_next(m, v, &l);
5119 if (!v)
5120 return NULL;
5121 }
5122
5123 return v;
5124}
5125
5126static void saved_cmdlines_stop(struct seq_file *m, void *v)
5127{
5128 arch_spin_unlock(&trace_cmdline_lock);
5129 preempt_enable();
5130}
5131
5132static int saved_cmdlines_show(struct seq_file *m, void *v)
5133{
5134 char buf[TASK_COMM_LEN];
5135 unsigned int *pid = v;
5136
5137 __trace_find_cmdline(*pid, buf);
5138 seq_printf(m, "%d %s\n", *pid, buf);
5139 return 0;
5140}
5141
5142static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
5143 .start = saved_cmdlines_start,
5144 .next = saved_cmdlines_next,
5145 .stop = saved_cmdlines_stop,
5146 .show = saved_cmdlines_show,
5147};
5148
5149static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
5150{
5151 int ret;
5152
5153 ret = tracing_check_open_get_tr(NULL);
5154 if (ret)
5155 return ret;
5156
5157 return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
5158}
5159
5160static const struct file_operations tracing_saved_cmdlines_fops = {
5161 .open = tracing_saved_cmdlines_open,
5162 .read = seq_read,
5163 .llseek = seq_lseek,
5164 .release = seq_release,
5165};
5166
5167static ssize_t
5168tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
5169 size_t cnt, loff_t *ppos)
5170{
5171 char buf[64];
5172 int r;
5173
5174 arch_spin_lock(&trace_cmdline_lock);
5175 r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
5176 arch_spin_unlock(&trace_cmdline_lock);
5177
5178 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5179}
5180
5181static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
5182{
5183 kfree(s->saved_cmdlines);
5184 kfree(s->map_cmdline_to_pid);
5185 kfree(s);
5186}
5187
5188static int tracing_resize_saved_cmdlines(unsigned int val)
5189{
5190 struct saved_cmdlines_buffer *s, *savedcmd_temp;
5191
5192 s = kmalloc(sizeof(*s), GFP_KERNEL);
5193 if (!s)
5194 return -ENOMEM;
5195
5196 if (allocate_cmdlines_buffer(val, s) < 0) {
5197 kfree(s);
5198 return -ENOMEM;
5199 }
5200
5201 arch_spin_lock(&trace_cmdline_lock);
5202 savedcmd_temp = savedcmd;
5203 savedcmd = s;
5204 arch_spin_unlock(&trace_cmdline_lock);
5205 free_saved_cmdlines_buffer(savedcmd_temp);
5206
5207 return 0;
5208}
5209
5210static ssize_t
5211tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
5212 size_t cnt, loff_t *ppos)
5213{
5214 unsigned long val;
5215 int ret;
5216
5217 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5218 if (ret)
5219 return ret;
5220
5221 /* must have at least 1 entry or less than PID_MAX_DEFAULT */
5222 if (!val || val > PID_MAX_DEFAULT)
5223 return -EINVAL;
5224
5225 ret = tracing_resize_saved_cmdlines((unsigned int)val);
5226 if (ret < 0)
5227 return ret;
5228
5229 *ppos += cnt;
5230
5231 return cnt;
5232}
5233
5234static const struct file_operations tracing_saved_cmdlines_size_fops = {
5235 .open = tracing_open_generic,
5236 .read = tracing_saved_cmdlines_size_read,
5237 .write = tracing_saved_cmdlines_size_write,
5238};
5239
5240#ifdef CONFIG_TRACE_EVAL_MAP_FILE
5241static union trace_eval_map_item *
5242update_eval_map(union trace_eval_map_item *ptr)
5243{
5244 if (!ptr->map.eval_string) {
5245 if (ptr->tail.next) {
5246 ptr = ptr->tail.next;
5247 /* Set ptr to the next real item (skip head) */
5248 ptr++;
5249 } else
5250 return NULL;
5251 }
5252 return ptr;
5253}
5254
5255static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
5256{
5257 union trace_eval_map_item *ptr = v;
5258
5259 /*
5260 * Paranoid! If ptr points to end, we don't want to increment past it.
5261 * This really should never happen.
5262 */
5263 ptr = update_eval_map(ptr);
5264 if (WARN_ON_ONCE(!ptr))
5265 return NULL;
5266
5267 ptr++;
5268
5269 (*pos)++;
5270
5271 ptr = update_eval_map(ptr);
5272
5273 return ptr;
5274}
5275
5276static void *eval_map_start(struct seq_file *m, loff_t *pos)
5277{
5278 union trace_eval_map_item *v;
5279 loff_t l = 0;
5280
5281 mutex_lock(&trace_eval_mutex);
5282
5283 v = trace_eval_maps;
5284 if (v)
5285 v++;
5286
5287 while (v && l < *pos) {
5288 v = eval_map_next(m, v, &l);
5289 }
5290
5291 return v;
5292}
5293
5294static void eval_map_stop(struct seq_file *m, void *v)
5295{
5296 mutex_unlock(&trace_eval_mutex);
5297}
5298
5299static int eval_map_show(struct seq_file *m, void *v)
5300{
5301 union trace_eval_map_item *ptr = v;
5302
5303 seq_printf(m, "%s %ld (%s)\n",
5304 ptr->map.eval_string, ptr->map.eval_value,
5305 ptr->map.system);
5306
5307 return 0;
5308}
5309
5310static const struct seq_operations tracing_eval_map_seq_ops = {
5311 .start = eval_map_start,
5312 .next = eval_map_next,
5313 .stop = eval_map_stop,
5314 .show = eval_map_show,
5315};
5316
5317static int tracing_eval_map_open(struct inode *inode, struct file *filp)
5318{
5319 int ret;
5320
5321 ret = tracing_check_open_get_tr(NULL);
5322 if (ret)
5323 return ret;
5324
5325 return seq_open(filp, &tracing_eval_map_seq_ops);
5326}
5327
5328static const struct file_operations tracing_eval_map_fops = {
5329 .open = tracing_eval_map_open,
5330 .read = seq_read,
5331 .llseek = seq_lseek,
5332 .release = seq_release,
5333};
5334
5335static inline union trace_eval_map_item *
5336trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
5337{
5338 /* Return tail of array given the head */
5339 return ptr + ptr->head.length + 1;
5340}
5341
5342static void
5343trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
5344 int len)
5345{
5346 struct trace_eval_map **stop;
5347 struct trace_eval_map **map;
5348 union trace_eval_map_item *map_array;
5349 union trace_eval_map_item *ptr;
5350
5351 stop = start + len;
5352
5353 /*
5354 * The trace_eval_maps contains the map plus a head and tail item,
5355 * where the head holds the module and length of array, and the
5356 * tail holds a pointer to the next list.
5357 */
5358 map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
5359 if (!map_array) {
5360 pr_warn("Unable to allocate trace eval mapping\n");
5361 return;
5362 }
5363
5364 mutex_lock(&trace_eval_mutex);
5365
5366 if (!trace_eval_maps)
5367 trace_eval_maps = map_array;
5368 else {
5369 ptr = trace_eval_maps;
5370 for (;;) {
5371 ptr = trace_eval_jmp_to_tail(ptr);
5372 if (!ptr->tail.next)
5373 break;
5374 ptr = ptr->tail.next;
5375
5376 }
5377 ptr->tail.next = map_array;
5378 }
5379 map_array->head.mod = mod;
5380 map_array->head.length = len;
5381 map_array++;
5382
5383 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
5384 map_array->map = **map;
5385 map_array++;
5386 }
5387 memset(map_array, 0, sizeof(*map_array));
5388
5389 mutex_unlock(&trace_eval_mutex);
5390}
5391
5392static void trace_create_eval_file(struct dentry *d_tracer)
5393{
5394 trace_create_file("eval_map", 0444, d_tracer,
5395 NULL, &tracing_eval_map_fops);
5396}
5397
5398#else /* CONFIG_TRACE_EVAL_MAP_FILE */
5399static inline void trace_create_eval_file(struct dentry *d_tracer) { }
5400static inline void trace_insert_eval_map_file(struct module *mod,
5401 struct trace_eval_map **start, int len) { }
5402#endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
5403
5404static void trace_insert_eval_map(struct module *mod,
5405 struct trace_eval_map **start, int len)
5406{
5407 struct trace_eval_map **map;
5408
5409 if (len <= 0)
5410 return;
5411
5412 map = start;
5413
5414 trace_event_eval_update(map, len);
5415
5416 trace_insert_eval_map_file(mod, start, len);
5417}
5418
5419static ssize_t
5420tracing_set_trace_read(struct file *filp, char __user *ubuf,
5421 size_t cnt, loff_t *ppos)
5422{
5423 struct trace_array *tr = filp->private_data;
5424 char buf[MAX_TRACER_SIZE+2];
5425 int r;
5426
5427 mutex_lock(&trace_types_lock);
5428 r = sprintf(buf, "%s\n", tr->current_trace->name);
5429 mutex_unlock(&trace_types_lock);
5430
5431 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5432}
5433
5434int tracer_init(struct tracer *t, struct trace_array *tr)
5435{
5436 tracing_reset_online_cpus(&tr->trace_buffer);
5437 return t->init(tr);
5438}
5439
5440static void set_buffer_entries(struct trace_buffer *buf, unsigned long val)
5441{
5442 int cpu;
5443
5444 for_each_tracing_cpu(cpu)
5445 per_cpu_ptr(buf->data, cpu)->entries = val;
5446}
5447
5448#ifdef CONFIG_TRACER_MAX_TRACE
5449/* resize @tr's buffer to the size of @size_tr's entries */
5450static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
5451 struct trace_buffer *size_buf, int cpu_id)
5452{
5453 int cpu, ret = 0;
5454
5455 if (cpu_id == RING_BUFFER_ALL_CPUS) {
5456 for_each_tracing_cpu(cpu) {
5457 ret = ring_buffer_resize(trace_buf->buffer,
5458 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
5459 if (ret < 0)
5460 break;
5461 per_cpu_ptr(trace_buf->data, cpu)->entries =
5462 per_cpu_ptr(size_buf->data, cpu)->entries;
5463 }
5464 } else {
5465 ret = ring_buffer_resize(trace_buf->buffer,
5466 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
5467 if (ret == 0)
5468 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
5469 per_cpu_ptr(size_buf->data, cpu_id)->entries;
5470 }
5471
5472 return ret;
5473}
5474#endif /* CONFIG_TRACER_MAX_TRACE */
5475
5476static int __tracing_resize_ring_buffer(struct trace_array *tr,
5477 unsigned long size, int cpu)
5478{
5479 int ret;
5480
5481 /*
5482 * If kernel or user changes the size of the ring buffer
5483 * we use the size that was given, and we can forget about
5484 * expanding it later.
5485 */
5486 ring_buffer_expanded = true;
5487
5488 /* May be called before buffers are initialized */
5489 if (!tr->trace_buffer.buffer)
5490 return 0;
5491
5492 ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu);
5493 if (ret < 0)
5494 return ret;
5495
5496#ifdef CONFIG_TRACER_MAX_TRACE
5497 if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
5498 !tr->current_trace->use_max_tr)
5499 goto out;
5500
5501 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
5502 if (ret < 0) {
5503 int r = resize_buffer_duplicate_size(&tr->trace_buffer,
5504 &tr->trace_buffer, cpu);
5505 if (r < 0) {
5506 /*
5507 * AARGH! We are left with different
5508 * size max buffer!!!!
5509 * The max buffer is our "snapshot" buffer.
5510 * When a tracer needs a snapshot (one of the
5511 * latency tracers), it swaps the max buffer
5512 * with the saved snap shot. We succeeded to
5513 * update the size of the main buffer, but failed to
5514 * update the size of the max buffer. But when we tried
5515 * to reset the main buffer to the original size, we
5516 * failed there too. This is very unlikely to
5517 * happen, but if it does, warn and kill all
5518 * tracing.
5519 */
5520 WARN_ON(1);
5521 tracing_disabled = 1;
5522 }
5523 return ret;
5524 }
5525
5526 if (cpu == RING_BUFFER_ALL_CPUS)
5527 set_buffer_entries(&tr->max_buffer, size);
5528 else
5529 per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
5530
5531 out:
5532#endif /* CONFIG_TRACER_MAX_TRACE */
5533
5534 if (cpu == RING_BUFFER_ALL_CPUS)
5535 set_buffer_entries(&tr->trace_buffer, size);
5536 else
5537 per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size;
5538
5539 return ret;
5540}
5541
5542static ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
5543 unsigned long size, int cpu_id)
5544{
5545 int ret = size;
5546
5547 mutex_lock(&trace_types_lock);
5548
5549 if (cpu_id != RING_BUFFER_ALL_CPUS) {
5550 /* make sure, this cpu is enabled in the mask */
5551 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
5552 ret = -EINVAL;
5553 goto out;
5554 }
5555 }
5556
5557 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
5558 if (ret < 0)
5559 ret = -ENOMEM;
5560
5561out:
5562 mutex_unlock(&trace_types_lock);
5563
5564 return ret;
5565}
5566
5567
5568/**
5569 * tracing_update_buffers - used by tracing facility to expand ring buffers
5570 *
5571 * To save on memory when the tracing is never used on a system with it
5572 * configured in. The ring buffers are set to a minimum size. But once
5573 * a user starts to use the tracing facility, then they need to grow
5574 * to their default size.
5575 *
5576 * This function is to be called when a tracer is about to be used.
5577 */
5578int tracing_update_buffers(void)
5579{
5580 int ret = 0;
5581
5582 mutex_lock(&trace_types_lock);
5583 if (!ring_buffer_expanded)
5584 ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
5585 RING_BUFFER_ALL_CPUS);
5586 mutex_unlock(&trace_types_lock);
5587
5588 return ret;
5589}
5590
5591struct trace_option_dentry;
5592
5593static void
5594create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
5595
5596/*
5597 * Used to clear out the tracer before deletion of an instance.
5598 * Must have trace_types_lock held.
5599 */
5600static void tracing_set_nop(struct trace_array *tr)
5601{
5602 if (tr->current_trace == &nop_trace)
5603 return;
5604
5605 tr->current_trace->enabled--;
5606
5607 if (tr->current_trace->reset)
5608 tr->current_trace->reset(tr);
5609
5610 tr->current_trace = &nop_trace;
5611}
5612
5613static void add_tracer_options(struct trace_array *tr, struct tracer *t)
5614{
5615 /* Only enable if the directory has been created already. */
5616 if (!tr->dir)
5617 return;
5618
5619 create_trace_option_files(tr, t);
5620}
5621
5622static int tracing_set_tracer(struct trace_array *tr, const char *buf)
5623{
5624 struct tracer *t;
5625#ifdef CONFIG_TRACER_MAX_TRACE
5626 bool had_max_tr;
5627#endif
5628 int ret = 0;
5629
5630 mutex_lock(&trace_types_lock);
5631
5632 if (!ring_buffer_expanded) {
5633 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
5634 RING_BUFFER_ALL_CPUS);
5635 if (ret < 0)
5636 goto out;
5637 ret = 0;
5638 }
5639
5640 for (t = trace_types; t; t = t->next) {
5641 if (strcmp(t->name, buf) == 0)
5642 break;
5643 }
5644 if (!t) {
5645 ret = -EINVAL;
5646 goto out;
5647 }
5648 if (t == tr->current_trace)
5649 goto out;
5650
5651#ifdef CONFIG_TRACER_SNAPSHOT
5652 if (t->use_max_tr) {
5653 arch_spin_lock(&tr->max_lock);
5654 if (tr->cond_snapshot)
5655 ret = -EBUSY;
5656 arch_spin_unlock(&tr->max_lock);
5657 if (ret)
5658 goto out;
5659 }
5660#endif
5661 /* Some tracers won't work on kernel command line */
5662 if (system_state < SYSTEM_RUNNING && t->noboot) {
5663 pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
5664 t->name);
5665 goto out;
5666 }
5667
5668 /* Some tracers are only allowed for the top level buffer */
5669 if (!trace_ok_for_array(t, tr)) {
5670 ret = -EINVAL;
5671 goto out;
5672 }
5673
5674 /* If trace pipe files are being read, we can't change the tracer */
5675 if (tr->current_trace->ref) {
5676 ret = -EBUSY;
5677 goto out;
5678 }
5679
5680 trace_branch_disable();
5681
5682 tr->current_trace->enabled--;
5683
5684 if (tr->current_trace->reset)
5685 tr->current_trace->reset(tr);
5686
5687 /* Current trace needs to be nop_trace before synchronize_rcu */
5688 tr->current_trace = &nop_trace;
5689
5690#ifdef CONFIG_TRACER_MAX_TRACE
5691 had_max_tr = tr->allocated_snapshot;
5692
5693 if (had_max_tr && !t->use_max_tr) {
5694 /*
5695 * We need to make sure that the update_max_tr sees that
5696 * current_trace changed to nop_trace to keep it from
5697 * swapping the buffers after we resize it.
5698 * The update_max_tr is called from interrupts disabled
5699 * so a synchronized_sched() is sufficient.
5700 */
5701 synchronize_rcu();
5702 free_snapshot(tr);
5703 }
5704#endif
5705
5706#ifdef CONFIG_TRACER_MAX_TRACE
5707 if (t->use_max_tr && !had_max_tr) {
5708 ret = tracing_alloc_snapshot_instance(tr);
5709 if (ret < 0)
5710 goto out;
5711 }
5712#endif
5713
5714 if (t->init) {
5715 ret = tracer_init(t, tr);
5716 if (ret)
5717 goto out;
5718 }
5719
5720 tr->current_trace = t;
5721 tr->current_trace->enabled++;
5722 trace_branch_enable(tr);
5723 out:
5724 mutex_unlock(&trace_types_lock);
5725
5726 return ret;
5727}
5728
5729static ssize_t
5730tracing_set_trace_write(struct file *filp, const char __user *ubuf,
5731 size_t cnt, loff_t *ppos)
5732{
5733 struct trace_array *tr = filp->private_data;
5734 char buf[MAX_TRACER_SIZE+1];
5735 int i;
5736 size_t ret;
5737 int err;
5738
5739 ret = cnt;
5740
5741 if (cnt > MAX_TRACER_SIZE)
5742 cnt = MAX_TRACER_SIZE;
5743
5744 if (copy_from_user(buf, ubuf, cnt))
5745 return -EFAULT;
5746
5747 buf[cnt] = 0;
5748
5749 /* strip ending whitespace. */
5750 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
5751 buf[i] = 0;
5752
5753 err = tracing_set_tracer(tr, buf);
5754 if (err)
5755 return err;
5756
5757 *ppos += ret;
5758
5759 return ret;
5760}
5761
5762static ssize_t
5763tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
5764 size_t cnt, loff_t *ppos)
5765{
5766 char buf[64];
5767 int r;
5768
5769 r = snprintf(buf, sizeof(buf), "%ld\n",
5770 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
5771 if (r > sizeof(buf))
5772 r = sizeof(buf);
5773 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5774}
5775
5776static ssize_t
5777tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
5778 size_t cnt, loff_t *ppos)
5779{
5780 unsigned long val;
5781 int ret;
5782
5783 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5784 if (ret)
5785 return ret;
5786
5787 *ptr = val * 1000;
5788
5789 return cnt;
5790}
5791
5792static ssize_t
5793tracing_thresh_read(struct file *filp, char __user *ubuf,
5794 size_t cnt, loff_t *ppos)
5795{
5796 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
5797}
5798
5799static ssize_t
5800tracing_thresh_write(struct file *filp, const char __user *ubuf,
5801 size_t cnt, loff_t *ppos)
5802{
5803 struct trace_array *tr = filp->private_data;
5804 int ret;
5805
5806 mutex_lock(&trace_types_lock);
5807 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
5808 if (ret < 0)
5809 goto out;
5810
5811 if (tr->current_trace->update_thresh) {
5812 ret = tr->current_trace->update_thresh(tr);
5813 if (ret < 0)
5814 goto out;
5815 }
5816
5817 ret = cnt;
5818out:
5819 mutex_unlock(&trace_types_lock);
5820
5821 return ret;
5822}
5823
5824#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
5825
5826static ssize_t
5827tracing_max_lat_read(struct file *filp, char __user *ubuf,
5828 size_t cnt, loff_t *ppos)
5829{
5830 return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
5831}
5832
5833static ssize_t
5834tracing_max_lat_write(struct file *filp, const char __user *ubuf,
5835 size_t cnt, loff_t *ppos)
5836{
5837 return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
5838}
5839
5840#endif
5841
5842static int tracing_open_pipe(struct inode *inode, struct file *filp)
5843{
5844 struct trace_array *tr = inode->i_private;
5845 struct trace_iterator *iter;
5846 int ret;
5847
5848 ret = tracing_check_open_get_tr(tr);
5849 if (ret)
5850 return ret;
5851
5852 mutex_lock(&trace_types_lock);
5853
5854 /* create a buffer to store the information to pass to userspace */
5855 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
5856 if (!iter) {
5857 ret = -ENOMEM;
5858 __trace_array_put(tr);
5859 goto out;
5860 }
5861
5862 trace_seq_init(&iter->seq);
5863 iter->trace = tr->current_trace;
5864
5865 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
5866 ret = -ENOMEM;
5867 goto fail;
5868 }
5869
5870 /* trace pipe does not show start of buffer */
5871 cpumask_setall(iter->started);
5872
5873 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
5874 iter->iter_flags |= TRACE_FILE_LAT_FMT;
5875
5876 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
5877 if (trace_clocks[tr->clock_id].in_ns)
5878 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
5879
5880 iter->tr = tr;
5881 iter->trace_buffer = &tr->trace_buffer;
5882 iter->cpu_file = tracing_get_cpu(inode);
5883 mutex_init(&iter->mutex);
5884 filp->private_data = iter;
5885
5886 if (iter->trace->pipe_open)
5887 iter->trace->pipe_open(iter);
5888
5889 nonseekable_open(inode, filp);
5890
5891 tr->current_trace->ref++;
5892out:
5893 mutex_unlock(&trace_types_lock);
5894 return ret;
5895
5896fail:
5897 kfree(iter);
5898 __trace_array_put(tr);
5899 mutex_unlock(&trace_types_lock);
5900 return ret;
5901}
5902
5903static int tracing_release_pipe(struct inode *inode, struct file *file)
5904{
5905 struct trace_iterator *iter = file->private_data;
5906 struct trace_array *tr = inode->i_private;
5907
5908 mutex_lock(&trace_types_lock);
5909
5910 tr->current_trace->ref--;
5911
5912 if (iter->trace->pipe_close)
5913 iter->trace->pipe_close(iter);
5914
5915 mutex_unlock(&trace_types_lock);
5916
5917 free_cpumask_var(iter->started);
5918 mutex_destroy(&iter->mutex);
5919 kfree(iter);
5920
5921 trace_array_put(tr);
5922
5923 return 0;
5924}
5925
5926static __poll_t
5927trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
5928{
5929 struct trace_array *tr = iter->tr;
5930
5931 /* Iterators are static, they should be filled or empty */
5932 if (trace_buffer_iter(iter, iter->cpu_file))
5933 return EPOLLIN | EPOLLRDNORM;
5934
5935 if (tr->trace_flags & TRACE_ITER_BLOCK)
5936 /*
5937 * Always select as readable when in blocking mode
5938 */
5939 return EPOLLIN | EPOLLRDNORM;
5940 else
5941 return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file,
5942 filp, poll_table);
5943}
5944
5945static __poll_t
5946tracing_poll_pipe(struct file *filp, poll_table *poll_table)
5947{
5948 struct trace_iterator *iter = filp->private_data;
5949
5950 return trace_poll(iter, filp, poll_table);
5951}
5952
5953/* Must be called with iter->mutex held. */
5954static int tracing_wait_pipe(struct file *filp)
5955{
5956 struct trace_iterator *iter = filp->private_data;
5957 int ret;
5958
5959 while (trace_empty(iter)) {
5960
5961 if ((filp->f_flags & O_NONBLOCK)) {
5962 return -EAGAIN;
5963 }
5964
5965 /*
5966 * We block until we read something and tracing is disabled.
5967 * We still block if tracing is disabled, but we have never
5968 * read anything. This allows a user to cat this file, and
5969 * then enable tracing. But after we have read something,
5970 * we give an EOF when tracing is again disabled.
5971 *
5972 * iter->pos will be 0 if we haven't read anything.
5973 */
5974 if (!tracer_tracing_is_on(iter->tr) && iter->pos)
5975 break;
5976
5977 mutex_unlock(&iter->mutex);
5978
5979 ret = wait_on_pipe(iter, 0);
5980
5981 mutex_lock(&iter->mutex);
5982
5983 if (ret)
5984 return ret;
5985 }
5986
5987 return 1;
5988}
5989
5990/*
5991 * Consumer reader.
5992 */
5993static ssize_t
5994tracing_read_pipe(struct file *filp, char __user *ubuf,
5995 size_t cnt, loff_t *ppos)
5996{
5997 struct trace_iterator *iter = filp->private_data;
5998 ssize_t sret;
5999
6000 /*
6001 * Avoid more than one consumer on a single file descriptor
6002 * This is just a matter of traces coherency, the ring buffer itself
6003 * is protected.
6004 */
6005 mutex_lock(&iter->mutex);
6006
6007 /* return any leftover data */
6008 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6009 if (sret != -EBUSY)
6010 goto out;
6011
6012 trace_seq_init(&iter->seq);
6013
6014 if (iter->trace->read) {
6015 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
6016 if (sret)
6017 goto out;
6018 }
6019
6020waitagain:
6021 sret = tracing_wait_pipe(filp);
6022 if (sret <= 0)
6023 goto out;
6024
6025 /* stop when tracing is finished */
6026 if (trace_empty(iter)) {
6027 sret = 0;
6028 goto out;
6029 }
6030
6031 if (cnt >= PAGE_SIZE)
6032 cnt = PAGE_SIZE - 1;
6033
6034 /* reset all but tr, trace, and overruns */
6035 memset(&iter->seq, 0,
6036 sizeof(struct trace_iterator) -
6037 offsetof(struct trace_iterator, seq));
6038 cpumask_clear(iter->started);
6039 trace_seq_init(&iter->seq);
6040 iter->pos = -1;
6041
6042 trace_event_read_lock();
6043 trace_access_lock(iter->cpu_file);
6044 while (trace_find_next_entry_inc(iter) != NULL) {
6045 enum print_line_t ret;
6046 int save_len = iter->seq.seq.len;
6047
6048 ret = print_trace_line(iter);
6049 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6050 /* don't print partial lines */
6051 iter->seq.seq.len = save_len;
6052 break;
6053 }
6054 if (ret != TRACE_TYPE_NO_CONSUME)
6055 trace_consume(iter);
6056
6057 if (trace_seq_used(&iter->seq) >= cnt)
6058 break;
6059
6060 /*
6061 * Setting the full flag means we reached the trace_seq buffer
6062 * size and we should leave by partial output condition above.
6063 * One of the trace_seq_* functions is not used properly.
6064 */
6065 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
6066 iter->ent->type);
6067 }
6068 trace_access_unlock(iter->cpu_file);
6069 trace_event_read_unlock();
6070
6071 /* Now copy what we have to the user */
6072 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6073 if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
6074 trace_seq_init(&iter->seq);
6075
6076 /*
6077 * If there was nothing to send to user, in spite of consuming trace
6078 * entries, go back to wait for more entries.
6079 */
6080 if (sret == -EBUSY)
6081 goto waitagain;
6082
6083out:
6084 mutex_unlock(&iter->mutex);
6085
6086 return sret;
6087}
6088
6089static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
6090 unsigned int idx)
6091{
6092 __free_page(spd->pages[idx]);
6093}
6094
6095static const struct pipe_buf_operations tracing_pipe_buf_ops = {
6096 .confirm = generic_pipe_buf_confirm,
6097 .release = generic_pipe_buf_release,
6098 .steal = generic_pipe_buf_steal,
6099 .get = generic_pipe_buf_get,
6100};
6101
6102static size_t
6103tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
6104{
6105 size_t count;
6106 int save_len;
6107 int ret;
6108
6109 /* Seq buffer is page-sized, exactly what we need. */
6110 for (;;) {
6111 save_len = iter->seq.seq.len;
6112 ret = print_trace_line(iter);
6113
6114 if (trace_seq_has_overflowed(&iter->seq)) {
6115 iter->seq.seq.len = save_len;
6116 break;
6117 }
6118
6119 /*
6120 * This should not be hit, because it should only
6121 * be set if the iter->seq overflowed. But check it
6122 * anyway to be safe.
6123 */
6124 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6125 iter->seq.seq.len = save_len;
6126 break;
6127 }
6128
6129 count = trace_seq_used(&iter->seq) - save_len;
6130 if (rem < count) {
6131 rem = 0;
6132 iter->seq.seq.len = save_len;
6133 break;
6134 }
6135
6136 if (ret != TRACE_TYPE_NO_CONSUME)
6137 trace_consume(iter);
6138 rem -= count;
6139 if (!trace_find_next_entry_inc(iter)) {
6140 rem = 0;
6141 iter->ent = NULL;
6142 break;
6143 }
6144 }
6145
6146 return rem;
6147}
6148
6149static ssize_t tracing_splice_read_pipe(struct file *filp,
6150 loff_t *ppos,
6151 struct pipe_inode_info *pipe,
6152 size_t len,
6153 unsigned int flags)
6154{
6155 struct page *pages_def[PIPE_DEF_BUFFERS];
6156 struct partial_page partial_def[PIPE_DEF_BUFFERS];
6157 struct trace_iterator *iter = filp->private_data;
6158 struct splice_pipe_desc spd = {
6159 .pages = pages_def,
6160 .partial = partial_def,
6161 .nr_pages = 0, /* This gets updated below. */
6162 .nr_pages_max = PIPE_DEF_BUFFERS,
6163 .ops = &tracing_pipe_buf_ops,
6164 .spd_release = tracing_spd_release_pipe,
6165 };
6166 ssize_t ret;
6167 size_t rem;
6168 unsigned int i;
6169
6170 if (splice_grow_spd(pipe, &spd))
6171 return -ENOMEM;
6172
6173 mutex_lock(&iter->mutex);
6174
6175 if (iter->trace->splice_read) {
6176 ret = iter->trace->splice_read(iter, filp,
6177 ppos, pipe, len, flags);
6178 if (ret)
6179 goto out_err;
6180 }
6181
6182 ret = tracing_wait_pipe(filp);
6183 if (ret <= 0)
6184 goto out_err;
6185
6186 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
6187 ret = -EFAULT;
6188 goto out_err;
6189 }
6190
6191 trace_event_read_lock();
6192 trace_access_lock(iter->cpu_file);
6193
6194 /* Fill as many pages as possible. */
6195 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
6196 spd.pages[i] = alloc_page(GFP_KERNEL);
6197 if (!spd.pages[i])
6198 break;
6199
6200 rem = tracing_fill_pipe_page(rem, iter);
6201
6202 /* Copy the data into the page, so we can start over. */
6203 ret = trace_seq_to_buffer(&iter->seq,
6204 page_address(spd.pages[i]),
6205 trace_seq_used(&iter->seq));
6206 if (ret < 0) {
6207 __free_page(spd.pages[i]);
6208 break;
6209 }
6210 spd.partial[i].offset = 0;
6211 spd.partial[i].len = trace_seq_used(&iter->seq);
6212
6213 trace_seq_init(&iter->seq);
6214 }
6215
6216 trace_access_unlock(iter->cpu_file);
6217 trace_event_read_unlock();
6218 mutex_unlock(&iter->mutex);
6219
6220 spd.nr_pages = i;
6221
6222 if (i)
6223 ret = splice_to_pipe(pipe, &spd);
6224 else
6225 ret = 0;
6226out:
6227 splice_shrink_spd(&spd);
6228 return ret;
6229
6230out_err:
6231 mutex_unlock(&iter->mutex);
6232 goto out;
6233}
6234
6235static ssize_t
6236tracing_entries_read(struct file *filp, char __user *ubuf,
6237 size_t cnt, loff_t *ppos)
6238{
6239 struct inode *inode = file_inode(filp);
6240 struct trace_array *tr = inode->i_private;
6241 int cpu = tracing_get_cpu(inode);
6242 char buf[64];
6243 int r = 0;
6244 ssize_t ret;
6245
6246 mutex_lock(&trace_types_lock);
6247
6248 if (cpu == RING_BUFFER_ALL_CPUS) {
6249 int cpu, buf_size_same;
6250 unsigned long size;
6251
6252 size = 0;
6253 buf_size_same = 1;
6254 /* check if all cpu sizes are same */
6255 for_each_tracing_cpu(cpu) {
6256 /* fill in the size from first enabled cpu */
6257 if (size == 0)
6258 size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries;
6259 if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) {
6260 buf_size_same = 0;
6261 break;
6262 }
6263 }
6264
6265 if (buf_size_same) {
6266 if (!ring_buffer_expanded)
6267 r = sprintf(buf, "%lu (expanded: %lu)\n",
6268 size >> 10,
6269 trace_buf_size >> 10);
6270 else
6271 r = sprintf(buf, "%lu\n", size >> 10);
6272 } else
6273 r = sprintf(buf, "X\n");
6274 } else
6275 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
6276
6277 mutex_unlock(&trace_types_lock);
6278
6279 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6280 return ret;
6281}
6282
6283static ssize_t
6284tracing_entries_write(struct file *filp, const char __user *ubuf,
6285 size_t cnt, loff_t *ppos)
6286{
6287 struct inode *inode = file_inode(filp);
6288 struct trace_array *tr = inode->i_private;
6289 unsigned long val;
6290 int ret;
6291
6292 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6293 if (ret)
6294 return ret;
6295
6296 /* must have at least 1 entry */
6297 if (!val)
6298 return -EINVAL;
6299
6300 /* value is in KB */
6301 val <<= 10;
6302 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
6303 if (ret < 0)
6304 return ret;
6305
6306 *ppos += cnt;
6307
6308 return cnt;
6309}
6310
6311static ssize_t
6312tracing_total_entries_read(struct file *filp, char __user *ubuf,
6313 size_t cnt, loff_t *ppos)
6314{
6315 struct trace_array *tr = filp->private_data;
6316 char buf[64];
6317 int r, cpu;
6318 unsigned long size = 0, expanded_size = 0;
6319
6320 mutex_lock(&trace_types_lock);
6321 for_each_tracing_cpu(cpu) {
6322 size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10;
6323 if (!ring_buffer_expanded)
6324 expanded_size += trace_buf_size >> 10;
6325 }
6326 if (ring_buffer_expanded)
6327 r = sprintf(buf, "%lu\n", size);
6328 else
6329 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
6330 mutex_unlock(&trace_types_lock);
6331
6332 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6333}
6334
6335static ssize_t
6336tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
6337 size_t cnt, loff_t *ppos)
6338{
6339 /*
6340 * There is no need to read what the user has written, this function
6341 * is just to make sure that there is no error when "echo" is used
6342 */
6343
6344 *ppos += cnt;
6345
6346 return cnt;
6347}
6348
6349static int
6350tracing_free_buffer_release(struct inode *inode, struct file *filp)
6351{
6352 struct trace_array *tr = inode->i_private;
6353
6354 /* disable tracing ? */
6355 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
6356 tracer_tracing_off(tr);
6357 /* resize the ring buffer to 0 */
6358 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
6359
6360 trace_array_put(tr);
6361
6362 return 0;
6363}
6364
6365static ssize_t
6366tracing_mark_write(struct file *filp, const char __user *ubuf,
6367 size_t cnt, loff_t *fpos)
6368{
6369 struct trace_array *tr = filp->private_data;
6370 struct ring_buffer_event *event;
6371 enum event_trigger_type tt = ETT_NONE;
6372 struct ring_buffer *buffer;
6373 struct print_entry *entry;
6374 unsigned long irq_flags;
6375 ssize_t written;
6376 int size;
6377 int len;
6378
6379/* Used in tracing_mark_raw_write() as well */
6380#define FAULTED_STR "<faulted>"
6381#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */
6382
6383 if (tracing_disabled)
6384 return -EINVAL;
6385
6386 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
6387 return -EINVAL;
6388
6389 if (cnt > TRACE_BUF_SIZE)
6390 cnt = TRACE_BUF_SIZE;
6391
6392 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
6393
6394 local_save_flags(irq_flags);
6395 size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */
6396
6397 /* If less than "<faulted>", then make sure we can still add that */
6398 if (cnt < FAULTED_SIZE)
6399 size += FAULTED_SIZE - cnt;
6400
6401 buffer = tr->trace_buffer.buffer;
6402 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
6403 irq_flags, preempt_count());
6404 if (unlikely(!event))
6405 /* Ring buffer disabled, return as if not open for write */
6406 return -EBADF;
6407
6408 entry = ring_buffer_event_data(event);
6409 entry->ip = _THIS_IP_;
6410
6411 len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
6412 if (len) {
6413 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
6414 cnt = FAULTED_SIZE;
6415 written = -EFAULT;
6416 } else
6417 written = cnt;
6418 len = cnt;
6419
6420 if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
6421 /* do not add \n before testing triggers, but add \0 */
6422 entry->buf[cnt] = '\0';
6423 tt = event_triggers_call(tr->trace_marker_file, entry, event);
6424 }
6425
6426 if (entry->buf[cnt - 1] != '\n') {
6427 entry->buf[cnt] = '\n';
6428 entry->buf[cnt + 1] = '\0';
6429 } else
6430 entry->buf[cnt] = '\0';
6431
6432 __buffer_unlock_commit(buffer, event);
6433
6434 if (tt)
6435 event_triggers_post_call(tr->trace_marker_file, tt);
6436
6437 if (written > 0)
6438 *fpos += written;
6439
6440 return written;
6441}
6442
6443/* Limit it for now to 3K (including tag) */
6444#define RAW_DATA_MAX_SIZE (1024*3)
6445
6446static ssize_t
6447tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
6448 size_t cnt, loff_t *fpos)
6449{
6450 struct trace_array *tr = filp->private_data;
6451 struct ring_buffer_event *event;
6452 struct ring_buffer *buffer;
6453 struct raw_data_entry *entry;
6454 unsigned long irq_flags;
6455 ssize_t written;
6456 int size;
6457 int len;
6458
6459#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
6460
6461 if (tracing_disabled)
6462 return -EINVAL;
6463
6464 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
6465 return -EINVAL;
6466
6467 /* The marker must at least have a tag id */
6468 if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE)
6469 return -EINVAL;
6470
6471 if (cnt > TRACE_BUF_SIZE)
6472 cnt = TRACE_BUF_SIZE;
6473
6474 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
6475
6476 local_save_flags(irq_flags);
6477 size = sizeof(*entry) + cnt;
6478 if (cnt < FAULT_SIZE_ID)
6479 size += FAULT_SIZE_ID - cnt;
6480
6481 buffer = tr->trace_buffer.buffer;
6482 event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
6483 irq_flags, preempt_count());
6484 if (!event)
6485 /* Ring buffer disabled, return as if not open for write */
6486 return -EBADF;
6487
6488 entry = ring_buffer_event_data(event);
6489
6490 len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
6491 if (len) {
6492 entry->id = -1;
6493 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
6494 written = -EFAULT;
6495 } else
6496 written = cnt;
6497
6498 __buffer_unlock_commit(buffer, event);
6499
6500 if (written > 0)
6501 *fpos += written;
6502
6503 return written;
6504}
6505
6506static int tracing_clock_show(struct seq_file *m, void *v)
6507{
6508 struct trace_array *tr = m->private;
6509 int i;
6510
6511 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
6512 seq_printf(m,
6513 "%s%s%s%s", i ? " " : "",
6514 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
6515 i == tr->clock_id ? "]" : "");
6516 seq_putc(m, '\n');
6517
6518 return 0;
6519}
6520
6521int tracing_set_clock(struct trace_array *tr, const char *clockstr)
6522{
6523 int i;
6524
6525 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
6526 if (strcmp(trace_clocks[i].name, clockstr) == 0)
6527 break;
6528 }
6529 if (i == ARRAY_SIZE(trace_clocks))
6530 return -EINVAL;
6531
6532 mutex_lock(&trace_types_lock);
6533
6534 tr->clock_id = i;
6535
6536 ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func);
6537
6538 /*
6539 * New clock may not be consistent with the previous clock.
6540 * Reset the buffer so that it doesn't have incomparable timestamps.
6541 */
6542 tracing_reset_online_cpus(&tr->trace_buffer);
6543
6544#ifdef CONFIG_TRACER_MAX_TRACE
6545 if (tr->max_buffer.buffer)
6546 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
6547 tracing_reset_online_cpus(&tr->max_buffer);
6548#endif
6549
6550 mutex_unlock(&trace_types_lock);
6551
6552 return 0;
6553}
6554
6555static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
6556 size_t cnt, loff_t *fpos)
6557{
6558 struct seq_file *m = filp->private_data;
6559 struct trace_array *tr = m->private;
6560 char buf[64];
6561 const char *clockstr;
6562 int ret;
6563
6564 if (cnt >= sizeof(buf))
6565 return -EINVAL;
6566
6567 if (copy_from_user(buf, ubuf, cnt))
6568 return -EFAULT;
6569
6570 buf[cnt] = 0;
6571
6572 clockstr = strstrip(buf);
6573
6574 ret = tracing_set_clock(tr, clockstr);
6575 if (ret)
6576 return ret;
6577
6578 *fpos += cnt;
6579
6580 return cnt;
6581}
6582
6583static int tracing_clock_open(struct inode *inode, struct file *file)
6584{
6585 struct trace_array *tr = inode->i_private;
6586 int ret;
6587
6588 ret = tracing_check_open_get_tr(tr);
6589 if (ret)
6590 return ret;
6591
6592 ret = single_open(file, tracing_clock_show, inode->i_private);
6593 if (ret < 0)
6594 trace_array_put(tr);
6595
6596 return ret;
6597}
6598
6599static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
6600{
6601 struct trace_array *tr = m->private;
6602
6603 mutex_lock(&trace_types_lock);
6604
6605 if (ring_buffer_time_stamp_abs(tr->trace_buffer.buffer))
6606 seq_puts(m, "delta [absolute]\n");
6607 else
6608 seq_puts(m, "[delta] absolute\n");
6609
6610 mutex_unlock(&trace_types_lock);
6611
6612 return 0;
6613}
6614
6615static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
6616{
6617 struct trace_array *tr = inode->i_private;
6618 int ret;
6619
6620 ret = tracing_check_open_get_tr(tr);
6621 if (ret)
6622 return ret;
6623
6624 ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
6625 if (ret < 0)
6626 trace_array_put(tr);
6627
6628 return ret;
6629}
6630
6631int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs)
6632{
6633 int ret = 0;
6634
6635 mutex_lock(&trace_types_lock);
6636
6637 if (abs && tr->time_stamp_abs_ref++)
6638 goto out;
6639
6640 if (!abs) {
6641 if (WARN_ON_ONCE(!tr->time_stamp_abs_ref)) {
6642 ret = -EINVAL;
6643 goto out;
6644 }
6645
6646 if (--tr->time_stamp_abs_ref)
6647 goto out;
6648 }
6649
6650 ring_buffer_set_time_stamp_abs(tr->trace_buffer.buffer, abs);
6651
6652#ifdef CONFIG_TRACER_MAX_TRACE
6653 if (tr->max_buffer.buffer)
6654 ring_buffer_set_time_stamp_abs(tr->max_buffer.buffer, abs);
6655#endif
6656 out:
6657 mutex_unlock(&trace_types_lock);
6658
6659 return ret;
6660}
6661
6662struct ftrace_buffer_info {
6663 struct trace_iterator iter;
6664 void *spare;
6665 unsigned int spare_cpu;
6666 unsigned int read;
6667};
6668
6669#ifdef CONFIG_TRACER_SNAPSHOT
6670static int tracing_snapshot_open(struct inode *inode, struct file *file)
6671{
6672 struct trace_array *tr = inode->i_private;
6673 struct trace_iterator *iter;
6674 struct seq_file *m;
6675 int ret;
6676
6677 ret = tracing_check_open_get_tr(tr);
6678 if (ret)
6679 return ret;
6680
6681 if (file->f_mode & FMODE_READ) {
6682 iter = __tracing_open(inode, file, true);
6683 if (IS_ERR(iter))
6684 ret = PTR_ERR(iter);
6685 } else {
6686 /* Writes still need the seq_file to hold the private data */
6687 ret = -ENOMEM;
6688 m = kzalloc(sizeof(*m), GFP_KERNEL);
6689 if (!m)
6690 goto out;
6691 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
6692 if (!iter) {
6693 kfree(m);
6694 goto out;
6695 }
6696 ret = 0;
6697
6698 iter->tr = tr;
6699 iter->trace_buffer = &tr->max_buffer;
6700 iter->cpu_file = tracing_get_cpu(inode);
6701 m->private = iter;
6702 file->private_data = m;
6703 }
6704out:
6705 if (ret < 0)
6706 trace_array_put(tr);
6707
6708 return ret;
6709}
6710
6711static ssize_t
6712tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
6713 loff_t *ppos)
6714{
6715 struct seq_file *m = filp->private_data;
6716 struct trace_iterator *iter = m->private;
6717 struct trace_array *tr = iter->tr;
6718 unsigned long val;
6719 int ret;
6720
6721 ret = tracing_update_buffers();
6722 if (ret < 0)
6723 return ret;
6724
6725 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6726 if (ret)
6727 return ret;
6728
6729 mutex_lock(&trace_types_lock);
6730
6731 if (tr->current_trace->use_max_tr) {
6732 ret = -EBUSY;
6733 goto out;
6734 }
6735
6736 arch_spin_lock(&tr->max_lock);
6737 if (tr->cond_snapshot)
6738 ret = -EBUSY;
6739 arch_spin_unlock(&tr->max_lock);
6740 if (ret)
6741 goto out;
6742
6743 switch (val) {
6744 case 0:
6745 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
6746 ret = -EINVAL;
6747 break;
6748 }
6749 if (tr->allocated_snapshot)
6750 free_snapshot(tr);
6751 break;
6752 case 1:
6753/* Only allow per-cpu swap if the ring buffer supports it */
6754#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
6755 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
6756 ret = -EINVAL;
6757 break;
6758 }
6759#endif
6760 if (tr->allocated_snapshot)
6761 ret = resize_buffer_duplicate_size(&tr->max_buffer,
6762 &tr->trace_buffer, iter->cpu_file);
6763 else
6764 ret = tracing_alloc_snapshot_instance(tr);
6765 if (ret < 0)
6766 break;
6767 local_irq_disable();
6768 /* Now, we're going to swap */
6769 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
6770 update_max_tr(tr, current, smp_processor_id(), NULL);
6771 else
6772 update_max_tr_single(tr, current, iter->cpu_file);
6773 local_irq_enable();
6774 break;
6775 default:
6776 if (tr->allocated_snapshot) {
6777 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
6778 tracing_reset_online_cpus(&tr->max_buffer);
6779 else
6780 tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
6781 }
6782 break;
6783 }
6784
6785 if (ret >= 0) {
6786 *ppos += cnt;
6787 ret = cnt;
6788 }
6789out:
6790 mutex_unlock(&trace_types_lock);
6791 return ret;
6792}
6793
6794static int tracing_snapshot_release(struct inode *inode, struct file *file)
6795{
6796 struct seq_file *m = file->private_data;
6797 int ret;
6798
6799 ret = tracing_release(inode, file);
6800
6801 if (file->f_mode & FMODE_READ)
6802 return ret;
6803
6804 /* If write only, the seq_file is just a stub */
6805 if (m)
6806 kfree(m->private);
6807 kfree(m);
6808
6809 return 0;
6810}
6811
6812static int tracing_buffers_open(struct inode *inode, struct file *filp);
6813static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
6814 size_t count, loff_t *ppos);
6815static int tracing_buffers_release(struct inode *inode, struct file *file);
6816static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
6817 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
6818
6819static int snapshot_raw_open(struct inode *inode, struct file *filp)
6820{
6821 struct ftrace_buffer_info *info;
6822 int ret;
6823
6824 /* The following checks for tracefs lockdown */
6825 ret = tracing_buffers_open(inode, filp);
6826 if (ret < 0)
6827 return ret;
6828
6829 info = filp->private_data;
6830
6831 if (info->iter.trace->use_max_tr) {
6832 tracing_buffers_release(inode, filp);
6833 return -EBUSY;
6834 }
6835
6836 info->iter.snapshot = true;
6837 info->iter.trace_buffer = &info->iter.tr->max_buffer;
6838
6839 return ret;
6840}
6841
6842#endif /* CONFIG_TRACER_SNAPSHOT */
6843
6844
6845static const struct file_operations tracing_thresh_fops = {
6846 .open = tracing_open_generic,
6847 .read = tracing_thresh_read,
6848 .write = tracing_thresh_write,
6849 .llseek = generic_file_llseek,
6850};
6851
6852#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
6853static const struct file_operations tracing_max_lat_fops = {
6854 .open = tracing_open_generic,
6855 .read = tracing_max_lat_read,
6856 .write = tracing_max_lat_write,
6857 .llseek = generic_file_llseek,
6858};
6859#endif
6860
6861static const struct file_operations set_tracer_fops = {
6862 .open = tracing_open_generic,
6863 .read = tracing_set_trace_read,
6864 .write = tracing_set_trace_write,
6865 .llseek = generic_file_llseek,
6866};
6867
6868static const struct file_operations tracing_pipe_fops = {
6869 .open = tracing_open_pipe,
6870 .poll = tracing_poll_pipe,
6871 .read = tracing_read_pipe,
6872 .splice_read = tracing_splice_read_pipe,
6873 .release = tracing_release_pipe,
6874 .llseek = no_llseek,
6875};
6876
6877static const struct file_operations tracing_entries_fops = {
6878 .open = tracing_open_generic_tr,
6879 .read = tracing_entries_read,
6880 .write = tracing_entries_write,
6881 .llseek = generic_file_llseek,
6882 .release = tracing_release_generic_tr,
6883};
6884
6885static const struct file_operations tracing_total_entries_fops = {
6886 .open = tracing_open_generic_tr,
6887 .read = tracing_total_entries_read,
6888 .llseek = generic_file_llseek,
6889 .release = tracing_release_generic_tr,
6890};
6891
6892static const struct file_operations tracing_free_buffer_fops = {
6893 .open = tracing_open_generic_tr,
6894 .write = tracing_free_buffer_write,
6895 .release = tracing_free_buffer_release,
6896};
6897
6898static const struct file_operations tracing_mark_fops = {
6899 .open = tracing_open_generic_tr,
6900 .write = tracing_mark_write,
6901 .llseek = generic_file_llseek,
6902 .release = tracing_release_generic_tr,
6903};
6904
6905static const struct file_operations tracing_mark_raw_fops = {
6906 .open = tracing_open_generic_tr,
6907 .write = tracing_mark_raw_write,
6908 .llseek = generic_file_llseek,
6909 .release = tracing_release_generic_tr,
6910};
6911
6912static const struct file_operations trace_clock_fops = {
6913 .open = tracing_clock_open,
6914 .read = seq_read,
6915 .llseek = seq_lseek,
6916 .release = tracing_single_release_tr,
6917 .write = tracing_clock_write,
6918};
6919
6920static const struct file_operations trace_time_stamp_mode_fops = {
6921 .open = tracing_time_stamp_mode_open,
6922 .read = seq_read,
6923 .llseek = seq_lseek,
6924 .release = tracing_single_release_tr,
6925};
6926
6927#ifdef CONFIG_TRACER_SNAPSHOT
6928static const struct file_operations snapshot_fops = {
6929 .open = tracing_snapshot_open,
6930 .read = seq_read,
6931 .write = tracing_snapshot_write,
6932 .llseek = tracing_lseek,
6933 .release = tracing_snapshot_release,
6934};
6935
6936static const struct file_operations snapshot_raw_fops = {
6937 .open = snapshot_raw_open,
6938 .read = tracing_buffers_read,
6939 .release = tracing_buffers_release,
6940 .splice_read = tracing_buffers_splice_read,
6941 .llseek = no_llseek,
6942};
6943
6944#endif /* CONFIG_TRACER_SNAPSHOT */
6945
6946#define TRACING_LOG_ERRS_MAX 8
6947#define TRACING_LOG_LOC_MAX 128
6948
6949#define CMD_PREFIX " Command: "
6950
6951struct err_info {
6952 const char **errs; /* ptr to loc-specific array of err strings */
6953 u8 type; /* index into errs -> specific err string */
6954 u8 pos; /* MAX_FILTER_STR_VAL = 256 */
6955 u64 ts;
6956};
6957
6958struct tracing_log_err {
6959 struct list_head list;
6960 struct err_info info;
6961 char loc[TRACING_LOG_LOC_MAX]; /* err location */
6962 char cmd[MAX_FILTER_STR_VAL]; /* what caused err */
6963};
6964
6965static DEFINE_MUTEX(tracing_err_log_lock);
6966
6967static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr)
6968{
6969 struct tracing_log_err *err;
6970
6971 if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
6972 err = kzalloc(sizeof(*err), GFP_KERNEL);
6973 if (!err)
6974 err = ERR_PTR(-ENOMEM);
6975 tr->n_err_log_entries++;
6976
6977 return err;
6978 }
6979
6980 err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
6981 list_del(&err->list);
6982
6983 return err;
6984}
6985
6986/**
6987 * err_pos - find the position of a string within a command for error careting
6988 * @cmd: The tracing command that caused the error
6989 * @str: The string to position the caret at within @cmd
6990 *
6991 * Finds the position of the first occurence of @str within @cmd. The
6992 * return value can be passed to tracing_log_err() for caret placement
6993 * within @cmd.
6994 *
6995 * Returns the index within @cmd of the first occurence of @str or 0
6996 * if @str was not found.
6997 */
6998unsigned int err_pos(char *cmd, const char *str)
6999{
7000 char *found;
7001
7002 if (WARN_ON(!strlen(cmd)))
7003 return 0;
7004
7005 found = strstr(cmd, str);
7006 if (found)
7007 return found - cmd;
7008
7009 return 0;
7010}
7011
7012/**
7013 * tracing_log_err - write an error to the tracing error log
7014 * @tr: The associated trace array for the error (NULL for top level array)
7015 * @loc: A string describing where the error occurred
7016 * @cmd: The tracing command that caused the error
7017 * @errs: The array of loc-specific static error strings
7018 * @type: The index into errs[], which produces the specific static err string
7019 * @pos: The position the caret should be placed in the cmd
7020 *
7021 * Writes an error into tracing/error_log of the form:
7022 *
7023 * <loc>: error: <text>
7024 * Command: <cmd>
7025 * ^
7026 *
7027 * tracing/error_log is a small log file containing the last
7028 * TRACING_LOG_ERRS_MAX errors (8). Memory for errors isn't allocated
7029 * unless there has been a tracing error, and the error log can be
7030 * cleared and have its memory freed by writing the empty string in
7031 * truncation mode to it i.e. echo > tracing/error_log.
7032 *
7033 * NOTE: the @errs array along with the @type param are used to
7034 * produce a static error string - this string is not copied and saved
7035 * when the error is logged - only a pointer to it is saved. See
7036 * existing callers for examples of how static strings are typically
7037 * defined for use with tracing_log_err().
7038 */
7039void tracing_log_err(struct trace_array *tr,
7040 const char *loc, const char *cmd,
7041 const char **errs, u8 type, u8 pos)
7042{
7043 struct tracing_log_err *err;
7044
7045 if (!tr)
7046 tr = &global_trace;
7047
7048 mutex_lock(&tracing_err_log_lock);
7049 err = get_tracing_log_err(tr);
7050 if (PTR_ERR(err) == -ENOMEM) {
7051 mutex_unlock(&tracing_err_log_lock);
7052 return;
7053 }
7054
7055 snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
7056 snprintf(err->cmd, MAX_FILTER_STR_VAL,"\n" CMD_PREFIX "%s\n", cmd);
7057
7058 err->info.errs = errs;
7059 err->info.type = type;
7060 err->info.pos = pos;
7061 err->info.ts = local_clock();
7062
7063 list_add_tail(&err->list, &tr->err_log);
7064 mutex_unlock(&tracing_err_log_lock);
7065}
7066
7067static void clear_tracing_err_log(struct trace_array *tr)
7068{
7069 struct tracing_log_err *err, *next;
7070
7071 mutex_lock(&tracing_err_log_lock);
7072 list_for_each_entry_safe(err, next, &tr->err_log, list) {
7073 list_del(&err->list);
7074 kfree(err);
7075 }
7076
7077 tr->n_err_log_entries = 0;
7078 mutex_unlock(&tracing_err_log_lock);
7079}
7080
7081static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
7082{
7083 struct trace_array *tr = m->private;
7084
7085 mutex_lock(&tracing_err_log_lock);
7086
7087 return seq_list_start(&tr->err_log, *pos);
7088}
7089
7090static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos)
7091{
7092 struct trace_array *tr = m->private;
7093
7094 return seq_list_next(v, &tr->err_log, pos);
7095}
7096
7097static void tracing_err_log_seq_stop(struct seq_file *m, void *v)
7098{
7099 mutex_unlock(&tracing_err_log_lock);
7100}
7101
7102static void tracing_err_log_show_pos(struct seq_file *m, u8 pos)
7103{
7104 u8 i;
7105
7106 for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++)
7107 seq_putc(m, ' ');
7108 for (i = 0; i < pos; i++)
7109 seq_putc(m, ' ');
7110 seq_puts(m, "^\n");
7111}
7112
7113static int tracing_err_log_seq_show(struct seq_file *m, void *v)
7114{
7115 struct tracing_log_err *err = v;
7116
7117 if (err) {
7118 const char *err_text = err->info.errs[err->info.type];
7119 u64 sec = err->info.ts;
7120 u32 nsec;
7121
7122 nsec = do_div(sec, NSEC_PER_SEC);
7123 seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000,
7124 err->loc, err_text);
7125 seq_printf(m, "%s", err->cmd);
7126 tracing_err_log_show_pos(m, err->info.pos);
7127 }
7128
7129 return 0;
7130}
7131
7132static const struct seq_operations tracing_err_log_seq_ops = {
7133 .start = tracing_err_log_seq_start,
7134 .next = tracing_err_log_seq_next,
7135 .stop = tracing_err_log_seq_stop,
7136 .show = tracing_err_log_seq_show
7137};
7138
7139static int tracing_err_log_open(struct inode *inode, struct file *file)
7140{
7141 struct trace_array *tr = inode->i_private;
7142 int ret = 0;
7143
7144 ret = tracing_check_open_get_tr(tr);
7145 if (ret)
7146 return ret;
7147
7148 /* If this file was opened for write, then erase contents */
7149 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
7150 clear_tracing_err_log(tr);
7151
7152 if (file->f_mode & FMODE_READ) {
7153 ret = seq_open(file, &tracing_err_log_seq_ops);
7154 if (!ret) {
7155 struct seq_file *m = file->private_data;
7156 m->private = tr;
7157 } else {
7158 trace_array_put(tr);
7159 }
7160 }
7161 return ret;
7162}
7163
7164static ssize_t tracing_err_log_write(struct file *file,
7165 const char __user *buffer,
7166 size_t count, loff_t *ppos)
7167{
7168 return count;
7169}
7170
7171static int tracing_err_log_release(struct inode *inode, struct file *file)
7172{
7173 struct trace_array *tr = inode->i_private;
7174
7175 trace_array_put(tr);
7176
7177 if (file->f_mode & FMODE_READ)
7178 seq_release(inode, file);
7179
7180 return 0;
7181}
7182
7183static const struct file_operations tracing_err_log_fops = {
7184 .open = tracing_err_log_open,
7185 .write = tracing_err_log_write,
7186 .read = seq_read,
7187 .llseek = seq_lseek,
7188 .release = tracing_err_log_release,
7189};
7190
7191static int tracing_buffers_open(struct inode *inode, struct file *filp)
7192{
7193 struct trace_array *tr = inode->i_private;
7194 struct ftrace_buffer_info *info;
7195 int ret;
7196
7197 ret = tracing_check_open_get_tr(tr);
7198 if (ret)
7199 return ret;
7200
7201 info = kzalloc(sizeof(*info), GFP_KERNEL);
7202 if (!info) {
7203 trace_array_put(tr);
7204 return -ENOMEM;
7205 }
7206
7207 mutex_lock(&trace_types_lock);
7208
7209 info->iter.tr = tr;
7210 info->iter.cpu_file = tracing_get_cpu(inode);
7211 info->iter.trace = tr->current_trace;
7212 info->iter.trace_buffer = &tr->trace_buffer;
7213 info->spare = NULL;
7214 /* Force reading ring buffer for first read */
7215 info->read = (unsigned int)-1;
7216
7217 filp->private_data = info;
7218
7219 tr->current_trace->ref++;
7220
7221 mutex_unlock(&trace_types_lock);
7222
7223 ret = nonseekable_open(inode, filp);
7224 if (ret < 0)
7225 trace_array_put(tr);
7226
7227 return ret;
7228}
7229
7230static __poll_t
7231tracing_buffers_poll(struct file *filp, poll_table *poll_table)
7232{
7233 struct ftrace_buffer_info *info = filp->private_data;
7234 struct trace_iterator *iter = &info->iter;
7235
7236 return trace_poll(iter, filp, poll_table);
7237}
7238
7239static ssize_t
7240tracing_buffers_read(struct file *filp, char __user *ubuf,
7241 size_t count, loff_t *ppos)
7242{
7243 struct ftrace_buffer_info *info = filp->private_data;
7244 struct trace_iterator *iter = &info->iter;
7245 ssize_t ret = 0;
7246 ssize_t size;
7247
7248 if (!count)
7249 return 0;
7250
7251#ifdef CONFIG_TRACER_MAX_TRACE
7252 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
7253 return -EBUSY;
7254#endif
7255
7256 if (!info->spare) {
7257 info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
7258 iter->cpu_file);
7259 if (IS_ERR(info->spare)) {
7260 ret = PTR_ERR(info->spare);
7261 info->spare = NULL;
7262 } else {
7263 info->spare_cpu = iter->cpu_file;
7264 }
7265 }
7266 if (!info->spare)
7267 return ret;
7268
7269 /* Do we have previous read data to read? */
7270 if (info->read < PAGE_SIZE)
7271 goto read;
7272
7273 again:
7274 trace_access_lock(iter->cpu_file);
7275 ret = ring_buffer_read_page(iter->trace_buffer->buffer,
7276 &info->spare,
7277 count,
7278 iter->cpu_file, 0);
7279 trace_access_unlock(iter->cpu_file);
7280
7281 if (ret < 0) {
7282 if (trace_empty(iter)) {
7283 if ((filp->f_flags & O_NONBLOCK))
7284 return -EAGAIN;
7285
7286 ret = wait_on_pipe(iter, 0);
7287 if (ret)
7288 return ret;
7289
7290 goto again;
7291 }
7292 return 0;
7293 }
7294
7295 info->read = 0;
7296 read:
7297 size = PAGE_SIZE - info->read;
7298 if (size > count)
7299 size = count;
7300
7301 ret = copy_to_user(ubuf, info->spare + info->read, size);
7302 if (ret == size)
7303 return -EFAULT;
7304
7305 size -= ret;
7306
7307 *ppos += size;
7308 info->read += size;
7309
7310 return size;
7311}
7312
7313static int tracing_buffers_release(struct inode *inode, struct file *file)
7314{
7315 struct ftrace_buffer_info *info = file->private_data;
7316 struct trace_iterator *iter = &info->iter;
7317
7318 mutex_lock(&trace_types_lock);
7319
7320 iter->tr->current_trace->ref--;
7321
7322 __trace_array_put(iter->tr);
7323
7324 if (info->spare)
7325 ring_buffer_free_read_page(iter->trace_buffer->buffer,
7326 info->spare_cpu, info->spare);
7327 kfree(info);
7328
7329 mutex_unlock(&trace_types_lock);
7330
7331 return 0;
7332}
7333
7334struct buffer_ref {
7335 struct ring_buffer *buffer;
7336 void *page;
7337 int cpu;
7338 refcount_t refcount;
7339};
7340
7341static void buffer_ref_release(struct buffer_ref *ref)
7342{
7343 if (!refcount_dec_and_test(&ref->refcount))
7344 return;
7345 ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
7346 kfree(ref);
7347}
7348
7349static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
7350 struct pipe_buffer *buf)
7351{
7352 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
7353
7354 buffer_ref_release(ref);
7355 buf->private = 0;
7356}
7357
7358static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
7359 struct pipe_buffer *buf)
7360{
7361 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
7362
7363 if (refcount_read(&ref->refcount) > INT_MAX/2)
7364 return false;
7365
7366 refcount_inc(&ref->refcount);
7367 return true;
7368}
7369
7370/* Pipe buffer operations for a buffer. */
7371static const struct pipe_buf_operations buffer_pipe_buf_ops = {
7372 .confirm = generic_pipe_buf_confirm,
7373 .release = buffer_pipe_buf_release,
7374 .steal = generic_pipe_buf_nosteal,
7375 .get = buffer_pipe_buf_get,
7376};
7377
7378/*
7379 * Callback from splice_to_pipe(), if we need to release some pages
7380 * at the end of the spd in case we error'ed out in filling the pipe.
7381 */
7382static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
7383{
7384 struct buffer_ref *ref =
7385 (struct buffer_ref *)spd->partial[i].private;
7386
7387 buffer_ref_release(ref);
7388 spd->partial[i].private = 0;
7389}
7390
7391static ssize_t
7392tracing_buffers_splice_read(struct file *file, loff_t *ppos,
7393 struct pipe_inode_info *pipe, size_t len,
7394 unsigned int flags)
7395{
7396 struct ftrace_buffer_info *info = file->private_data;
7397 struct trace_iterator *iter = &info->iter;
7398 struct partial_page partial_def[PIPE_DEF_BUFFERS];
7399 struct page *pages_def[PIPE_DEF_BUFFERS];
7400 struct splice_pipe_desc spd = {
7401 .pages = pages_def,
7402 .partial = partial_def,
7403 .nr_pages_max = PIPE_DEF_BUFFERS,
7404 .ops = &buffer_pipe_buf_ops,
7405 .spd_release = buffer_spd_release,
7406 };
7407 struct buffer_ref *ref;
7408 int entries, i;
7409 ssize_t ret = 0;
7410
7411#ifdef CONFIG_TRACER_MAX_TRACE
7412 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
7413 return -EBUSY;
7414#endif
7415
7416 if (*ppos & (PAGE_SIZE - 1))
7417 return -EINVAL;
7418
7419 if (len & (PAGE_SIZE - 1)) {
7420 if (len < PAGE_SIZE)
7421 return -EINVAL;
7422 len &= PAGE_MASK;
7423 }
7424
7425 if (splice_grow_spd(pipe, &spd))
7426 return -ENOMEM;
7427
7428 again:
7429 trace_access_lock(iter->cpu_file);
7430 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
7431
7432 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
7433 struct page *page;
7434 int r;
7435
7436 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
7437 if (!ref) {
7438 ret = -ENOMEM;
7439 break;
7440 }
7441
7442 refcount_set(&ref->refcount, 1);
7443 ref->buffer = iter->trace_buffer->buffer;
7444 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
7445 if (IS_ERR(ref->page)) {
7446 ret = PTR_ERR(ref->page);
7447 ref->page = NULL;
7448 kfree(ref);
7449 break;
7450 }
7451 ref->cpu = iter->cpu_file;
7452
7453 r = ring_buffer_read_page(ref->buffer, &ref->page,
7454 len, iter->cpu_file, 1);
7455 if (r < 0) {
7456 ring_buffer_free_read_page(ref->buffer, ref->cpu,
7457 ref->page);
7458 kfree(ref);
7459 break;
7460 }
7461
7462 page = virt_to_page(ref->page);
7463
7464 spd.pages[i] = page;
7465 spd.partial[i].len = PAGE_SIZE;
7466 spd.partial[i].offset = 0;
7467 spd.partial[i].private = (unsigned long)ref;
7468 spd.nr_pages++;
7469 *ppos += PAGE_SIZE;
7470
7471 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
7472 }
7473
7474 trace_access_unlock(iter->cpu_file);
7475 spd.nr_pages = i;
7476
7477 /* did we read anything? */
7478 if (!spd.nr_pages) {
7479 if (ret)
7480 goto out;
7481
7482 ret = -EAGAIN;
7483 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
7484 goto out;
7485
7486 ret = wait_on_pipe(iter, iter->tr->buffer_percent);
7487 if (ret)
7488 goto out;
7489
7490 goto again;
7491 }
7492
7493 ret = splice_to_pipe(pipe, &spd);
7494out:
7495 splice_shrink_spd(&spd);
7496
7497 return ret;
7498}
7499
7500static const struct file_operations tracing_buffers_fops = {
7501 .open = tracing_buffers_open,
7502 .read = tracing_buffers_read,
7503 .poll = tracing_buffers_poll,
7504 .release = tracing_buffers_release,
7505 .splice_read = tracing_buffers_splice_read,
7506 .llseek = no_llseek,
7507};
7508
7509static ssize_t
7510tracing_stats_read(struct file *filp, char __user *ubuf,
7511 size_t count, loff_t *ppos)
7512{
7513 struct inode *inode = file_inode(filp);
7514 struct trace_array *tr = inode->i_private;
7515 struct trace_buffer *trace_buf = &tr->trace_buffer;
7516 int cpu = tracing_get_cpu(inode);
7517 struct trace_seq *s;
7518 unsigned long cnt;
7519 unsigned long long t;
7520 unsigned long usec_rem;
7521
7522 s = kmalloc(sizeof(*s), GFP_KERNEL);
7523 if (!s)
7524 return -ENOMEM;
7525
7526 trace_seq_init(s);
7527
7528 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
7529 trace_seq_printf(s, "entries: %ld\n", cnt);
7530
7531 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
7532 trace_seq_printf(s, "overrun: %ld\n", cnt);
7533
7534 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
7535 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
7536
7537 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
7538 trace_seq_printf(s, "bytes: %ld\n", cnt);
7539
7540 if (trace_clocks[tr->clock_id].in_ns) {
7541 /* local or global for trace_clock */
7542 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
7543 usec_rem = do_div(t, USEC_PER_SEC);
7544 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
7545 t, usec_rem);
7546
7547 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu));
7548 usec_rem = do_div(t, USEC_PER_SEC);
7549 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
7550 } else {
7551 /* counter or tsc mode for trace_clock */
7552 trace_seq_printf(s, "oldest event ts: %llu\n",
7553 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
7554
7555 trace_seq_printf(s, "now ts: %llu\n",
7556 ring_buffer_time_stamp(trace_buf->buffer, cpu));
7557 }
7558
7559 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
7560 trace_seq_printf(s, "dropped events: %ld\n", cnt);
7561
7562 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
7563 trace_seq_printf(s, "read events: %ld\n", cnt);
7564
7565 count = simple_read_from_buffer(ubuf, count, ppos,
7566 s->buffer, trace_seq_used(s));
7567
7568 kfree(s);
7569
7570 return count;
7571}
7572
7573static const struct file_operations tracing_stats_fops = {
7574 .open = tracing_open_generic_tr,
7575 .read = tracing_stats_read,
7576 .llseek = generic_file_llseek,
7577 .release = tracing_release_generic_tr,
7578};
7579
7580#ifdef CONFIG_DYNAMIC_FTRACE
7581
7582static ssize_t
7583tracing_read_dyn_info(struct file *filp, char __user *ubuf,
7584 size_t cnt, loff_t *ppos)
7585{
7586 unsigned long *p = filp->private_data;
7587 char buf[64]; /* Not too big for a shallow stack */
7588 int r;
7589
7590 r = scnprintf(buf, 63, "%ld", *p);
7591 buf[r++] = '\n';
7592
7593 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7594}
7595
7596static const struct file_operations tracing_dyn_info_fops = {
7597 .open = tracing_open_generic,
7598 .read = tracing_read_dyn_info,
7599 .llseek = generic_file_llseek,
7600};
7601#endif /* CONFIG_DYNAMIC_FTRACE */
7602
7603#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
7604static void
7605ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
7606 struct trace_array *tr, struct ftrace_probe_ops *ops,
7607 void *data)
7608{
7609 tracing_snapshot_instance(tr);
7610}
7611
7612static void
7613ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
7614 struct trace_array *tr, struct ftrace_probe_ops *ops,
7615 void *data)
7616{
7617 struct ftrace_func_mapper *mapper = data;
7618 long *count = NULL;
7619
7620 if (mapper)
7621 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
7622
7623 if (count) {
7624
7625 if (*count <= 0)
7626 return;
7627
7628 (*count)--;
7629 }
7630
7631 tracing_snapshot_instance(tr);
7632}
7633
7634static int
7635ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
7636 struct ftrace_probe_ops *ops, void *data)
7637{
7638 struct ftrace_func_mapper *mapper = data;
7639 long *count = NULL;
7640
7641 seq_printf(m, "%ps:", (void *)ip);
7642
7643 seq_puts(m, "snapshot");
7644
7645 if (mapper)
7646 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
7647
7648 if (count)
7649 seq_printf(m, ":count=%ld\n", *count);
7650 else
7651 seq_puts(m, ":unlimited\n");
7652
7653 return 0;
7654}
7655
7656static int
7657ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
7658 unsigned long ip, void *init_data, void **data)
7659{
7660 struct ftrace_func_mapper *mapper = *data;
7661
7662 if (!mapper) {
7663 mapper = allocate_ftrace_func_mapper();
7664 if (!mapper)
7665 return -ENOMEM;
7666 *data = mapper;
7667 }
7668
7669 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
7670}
7671
7672static void
7673ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
7674 unsigned long ip, void *data)
7675{
7676 struct ftrace_func_mapper *mapper = data;
7677
7678 if (!ip) {
7679 if (!mapper)
7680 return;
7681 free_ftrace_func_mapper(mapper, NULL);
7682 return;
7683 }
7684
7685 ftrace_func_mapper_remove_ip(mapper, ip);
7686}
7687
7688static struct ftrace_probe_ops snapshot_probe_ops = {
7689 .func = ftrace_snapshot,
7690 .print = ftrace_snapshot_print,
7691};
7692
7693static struct ftrace_probe_ops snapshot_count_probe_ops = {
7694 .func = ftrace_count_snapshot,
7695 .print = ftrace_snapshot_print,
7696 .init = ftrace_snapshot_init,
7697 .free = ftrace_snapshot_free,
7698};
7699
7700static int
7701ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
7702 char *glob, char *cmd, char *param, int enable)
7703{
7704 struct ftrace_probe_ops *ops;
7705 void *count = (void *)-1;
7706 char *number;
7707 int ret;
7708
7709 if (!tr)
7710 return -ENODEV;
7711
7712 /* hash funcs only work with set_ftrace_filter */
7713 if (!enable)
7714 return -EINVAL;
7715
7716 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
7717
7718 if (glob[0] == '!')
7719 return unregister_ftrace_function_probe_func(glob+1, tr, ops);
7720
7721 if (!param)
7722 goto out_reg;
7723
7724 number = strsep(¶m, ":");
7725
7726 if (!strlen(number))
7727 goto out_reg;
7728
7729 /*
7730 * We use the callback data field (which is a pointer)
7731 * as our counter.
7732 */
7733 ret = kstrtoul(number, 0, (unsigned long *)&count);
7734 if (ret)
7735 return ret;
7736
7737 out_reg:
7738 ret = tracing_alloc_snapshot_instance(tr);
7739 if (ret < 0)
7740 goto out;
7741
7742 ret = register_ftrace_function_probe(glob, tr, ops, count);
7743
7744 out:
7745 return ret < 0 ? ret : 0;
7746}
7747
7748static struct ftrace_func_command ftrace_snapshot_cmd = {
7749 .name = "snapshot",
7750 .func = ftrace_trace_snapshot_callback,
7751};
7752
7753static __init int register_snapshot_cmd(void)
7754{
7755 return register_ftrace_command(&ftrace_snapshot_cmd);
7756}
7757#else
7758static inline __init int register_snapshot_cmd(void) { return 0; }
7759#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
7760
7761static struct dentry *tracing_get_dentry(struct trace_array *tr)
7762{
7763 if (WARN_ON(!tr->dir))
7764 return ERR_PTR(-ENODEV);
7765
7766 /* Top directory uses NULL as the parent */
7767 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
7768 return NULL;
7769
7770 /* All sub buffers have a descriptor */
7771 return tr->dir;
7772}
7773
7774static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
7775{
7776 struct dentry *d_tracer;
7777
7778 if (tr->percpu_dir)
7779 return tr->percpu_dir;
7780
7781 d_tracer = tracing_get_dentry(tr);
7782 if (IS_ERR(d_tracer))
7783 return NULL;
7784
7785 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
7786
7787 WARN_ONCE(!tr->percpu_dir,
7788 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
7789
7790 return tr->percpu_dir;
7791}
7792
7793static struct dentry *
7794trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
7795 void *data, long cpu, const struct file_operations *fops)
7796{
7797 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
7798
7799 if (ret) /* See tracing_get_cpu() */
7800 d_inode(ret)->i_cdev = (void *)(cpu + 1);
7801 return ret;
7802}
7803
7804static void
7805tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
7806{
7807 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
7808 struct dentry *d_cpu;
7809 char cpu_dir[30]; /* 30 characters should be more than enough */
7810
7811 if (!d_percpu)
7812 return;
7813
7814 snprintf(cpu_dir, 30, "cpu%ld", cpu);
7815 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
7816 if (!d_cpu) {
7817 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
7818 return;
7819 }
7820
7821 /* per cpu trace_pipe */
7822 trace_create_cpu_file("trace_pipe", 0444, d_cpu,
7823 tr, cpu, &tracing_pipe_fops);
7824
7825 /* per cpu trace */
7826 trace_create_cpu_file("trace", 0644, d_cpu,
7827 tr, cpu, &tracing_fops);
7828
7829 trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
7830 tr, cpu, &tracing_buffers_fops);
7831
7832 trace_create_cpu_file("stats", 0444, d_cpu,
7833 tr, cpu, &tracing_stats_fops);
7834
7835 trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
7836 tr, cpu, &tracing_entries_fops);
7837
7838#ifdef CONFIG_TRACER_SNAPSHOT
7839 trace_create_cpu_file("snapshot", 0644, d_cpu,
7840 tr, cpu, &snapshot_fops);
7841
7842 trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
7843 tr, cpu, &snapshot_raw_fops);
7844#endif
7845}
7846
7847#ifdef CONFIG_FTRACE_SELFTEST
7848/* Let selftest have access to static functions in this file */
7849#include "trace_selftest.c"
7850#endif
7851
7852static ssize_t
7853trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
7854 loff_t *ppos)
7855{
7856 struct trace_option_dentry *topt = filp->private_data;
7857 char *buf;
7858
7859 if (topt->flags->val & topt->opt->bit)
7860 buf = "1\n";
7861 else
7862 buf = "0\n";
7863
7864 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
7865}
7866
7867static ssize_t
7868trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
7869 loff_t *ppos)
7870{
7871 struct trace_option_dentry *topt = filp->private_data;
7872 unsigned long val;
7873 int ret;
7874
7875 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7876 if (ret)
7877 return ret;
7878
7879 if (val != 0 && val != 1)
7880 return -EINVAL;
7881
7882 if (!!(topt->flags->val & topt->opt->bit) != val) {
7883 mutex_lock(&trace_types_lock);
7884 ret = __set_tracer_option(topt->tr, topt->flags,
7885 topt->opt, !val);
7886 mutex_unlock(&trace_types_lock);
7887 if (ret)
7888 return ret;
7889 }
7890
7891 *ppos += cnt;
7892
7893 return cnt;
7894}
7895
7896
7897static const struct file_operations trace_options_fops = {
7898 .open = tracing_open_generic,
7899 .read = trace_options_read,
7900 .write = trace_options_write,
7901 .llseek = generic_file_llseek,
7902};
7903
7904/*
7905 * In order to pass in both the trace_array descriptor as well as the index
7906 * to the flag that the trace option file represents, the trace_array
7907 * has a character array of trace_flags_index[], which holds the index
7908 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
7909 * The address of this character array is passed to the flag option file
7910 * read/write callbacks.
7911 *
7912 * In order to extract both the index and the trace_array descriptor,
7913 * get_tr_index() uses the following algorithm.
7914 *
7915 * idx = *ptr;
7916 *
7917 * As the pointer itself contains the address of the index (remember
7918 * index[1] == 1).
7919 *
7920 * Then to get the trace_array descriptor, by subtracting that index
7921 * from the ptr, we get to the start of the index itself.
7922 *
7923 * ptr - idx == &index[0]
7924 *
7925 * Then a simple container_of() from that pointer gets us to the
7926 * trace_array descriptor.
7927 */
7928static void get_tr_index(void *data, struct trace_array **ptr,
7929 unsigned int *pindex)
7930{
7931 *pindex = *(unsigned char *)data;
7932
7933 *ptr = container_of(data - *pindex, struct trace_array,
7934 trace_flags_index);
7935}
7936
7937static ssize_t
7938trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
7939 loff_t *ppos)
7940{
7941 void *tr_index = filp->private_data;
7942 struct trace_array *tr;
7943 unsigned int index;
7944 char *buf;
7945
7946 get_tr_index(tr_index, &tr, &index);
7947
7948 if (tr->trace_flags & (1 << index))
7949 buf = "1\n";
7950 else
7951 buf = "0\n";
7952
7953 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
7954}
7955
7956static ssize_t
7957trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
7958 loff_t *ppos)
7959{
7960 void *tr_index = filp->private_data;
7961 struct trace_array *tr;
7962 unsigned int index;
7963 unsigned long val;
7964 int ret;
7965
7966 get_tr_index(tr_index, &tr, &index);
7967
7968 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7969 if (ret)
7970 return ret;
7971
7972 if (val != 0 && val != 1)
7973 return -EINVAL;
7974
7975 mutex_lock(&trace_types_lock);
7976 ret = set_tracer_flag(tr, 1 << index, val);
7977 mutex_unlock(&trace_types_lock);
7978
7979 if (ret < 0)
7980 return ret;
7981
7982 *ppos += cnt;
7983
7984 return cnt;
7985}
7986
7987static const struct file_operations trace_options_core_fops = {
7988 .open = tracing_open_generic,
7989 .read = trace_options_core_read,
7990 .write = trace_options_core_write,
7991 .llseek = generic_file_llseek,
7992};
7993
7994struct dentry *trace_create_file(const char *name,
7995 umode_t mode,
7996 struct dentry *parent,
7997 void *data,
7998 const struct file_operations *fops)
7999{
8000 struct dentry *ret;
8001
8002 ret = tracefs_create_file(name, mode, parent, data, fops);
8003 if (!ret)
8004 pr_warn("Could not create tracefs '%s' entry\n", name);
8005
8006 return ret;
8007}
8008
8009
8010static struct dentry *trace_options_init_dentry(struct trace_array *tr)
8011{
8012 struct dentry *d_tracer;
8013
8014 if (tr->options)
8015 return tr->options;
8016
8017 d_tracer = tracing_get_dentry(tr);
8018 if (IS_ERR(d_tracer))
8019 return NULL;
8020
8021 tr->options = tracefs_create_dir("options", d_tracer);
8022 if (!tr->options) {
8023 pr_warn("Could not create tracefs directory 'options'\n");
8024 return NULL;
8025 }
8026
8027 return tr->options;
8028}
8029
8030static void
8031create_trace_option_file(struct trace_array *tr,
8032 struct trace_option_dentry *topt,
8033 struct tracer_flags *flags,
8034 struct tracer_opt *opt)
8035{
8036 struct dentry *t_options;
8037
8038 t_options = trace_options_init_dentry(tr);
8039 if (!t_options)
8040 return;
8041
8042 topt->flags = flags;
8043 topt->opt = opt;
8044 topt->tr = tr;
8045
8046 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
8047 &trace_options_fops);
8048
8049}
8050
8051static void
8052create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
8053{
8054 struct trace_option_dentry *topts;
8055 struct trace_options *tr_topts;
8056 struct tracer_flags *flags;
8057 struct tracer_opt *opts;
8058 int cnt;
8059 int i;
8060
8061 if (!tracer)
8062 return;
8063
8064 flags = tracer->flags;
8065
8066 if (!flags || !flags->opts)
8067 return;
8068
8069 /*
8070 * If this is an instance, only create flags for tracers
8071 * the instance may have.
8072 */
8073 if (!trace_ok_for_array(tracer, tr))
8074 return;
8075
8076 for (i = 0; i < tr->nr_topts; i++) {
8077 /* Make sure there's no duplicate flags. */
8078 if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
8079 return;
8080 }
8081
8082 opts = flags->opts;
8083
8084 for (cnt = 0; opts[cnt].name; cnt++)
8085 ;
8086
8087 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
8088 if (!topts)
8089 return;
8090
8091 tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
8092 GFP_KERNEL);
8093 if (!tr_topts) {
8094 kfree(topts);
8095 return;
8096 }
8097
8098 tr->topts = tr_topts;
8099 tr->topts[tr->nr_topts].tracer = tracer;
8100 tr->topts[tr->nr_topts].topts = topts;
8101 tr->nr_topts++;
8102
8103 for (cnt = 0; opts[cnt].name; cnt++) {
8104 create_trace_option_file(tr, &topts[cnt], flags,
8105 &opts[cnt]);
8106 WARN_ONCE(topts[cnt].entry == NULL,
8107 "Failed to create trace option: %s",
8108 opts[cnt].name);
8109 }
8110}
8111
8112static struct dentry *
8113create_trace_option_core_file(struct trace_array *tr,
8114 const char *option, long index)
8115{
8116 struct dentry *t_options;
8117
8118 t_options = trace_options_init_dentry(tr);
8119 if (!t_options)
8120 return NULL;
8121
8122 return trace_create_file(option, 0644, t_options,
8123 (void *)&tr->trace_flags_index[index],
8124 &trace_options_core_fops);
8125}
8126
8127static void create_trace_options_dir(struct trace_array *tr)
8128{
8129 struct dentry *t_options;
8130 bool top_level = tr == &global_trace;
8131 int i;
8132
8133 t_options = trace_options_init_dentry(tr);
8134 if (!t_options)
8135 return;
8136
8137 for (i = 0; trace_options[i]; i++) {
8138 if (top_level ||
8139 !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
8140 create_trace_option_core_file(tr, trace_options[i], i);
8141 }
8142}
8143
8144static ssize_t
8145rb_simple_read(struct file *filp, char __user *ubuf,
8146 size_t cnt, loff_t *ppos)
8147{
8148 struct trace_array *tr = filp->private_data;
8149 char buf[64];
8150 int r;
8151
8152 r = tracer_tracing_is_on(tr);
8153 r = sprintf(buf, "%d\n", r);
8154
8155 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8156}
8157
8158static ssize_t
8159rb_simple_write(struct file *filp, const char __user *ubuf,
8160 size_t cnt, loff_t *ppos)
8161{
8162 struct trace_array *tr = filp->private_data;
8163 struct ring_buffer *buffer = tr->trace_buffer.buffer;
8164 unsigned long val;
8165 int ret;
8166
8167 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8168 if (ret)
8169 return ret;
8170
8171 if (buffer) {
8172 mutex_lock(&trace_types_lock);
8173 if (!!val == tracer_tracing_is_on(tr)) {
8174 val = 0; /* do nothing */
8175 } else if (val) {
8176 tracer_tracing_on(tr);
8177 if (tr->current_trace->start)
8178 tr->current_trace->start(tr);
8179 } else {
8180 tracer_tracing_off(tr);
8181 if (tr->current_trace->stop)
8182 tr->current_trace->stop(tr);
8183 }
8184 mutex_unlock(&trace_types_lock);
8185 }
8186
8187 (*ppos)++;
8188
8189 return cnt;
8190}
8191
8192static const struct file_operations rb_simple_fops = {
8193 .open = tracing_open_generic_tr,
8194 .read = rb_simple_read,
8195 .write = rb_simple_write,
8196 .release = tracing_release_generic_tr,
8197 .llseek = default_llseek,
8198};
8199
8200static ssize_t
8201buffer_percent_read(struct file *filp, char __user *ubuf,
8202 size_t cnt, loff_t *ppos)
8203{
8204 struct trace_array *tr = filp->private_data;
8205 char buf[64];
8206 int r;
8207
8208 r = tr->buffer_percent;
8209 r = sprintf(buf, "%d\n", r);
8210
8211 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8212}
8213
8214static ssize_t
8215buffer_percent_write(struct file *filp, const char __user *ubuf,
8216 size_t cnt, loff_t *ppos)
8217{
8218 struct trace_array *tr = filp->private_data;
8219 unsigned long val;
8220 int ret;
8221
8222 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8223 if (ret)
8224 return ret;
8225
8226 if (val > 100)
8227 return -EINVAL;
8228
8229 if (!val)
8230 val = 1;
8231
8232 tr->buffer_percent = val;
8233
8234 (*ppos)++;
8235
8236 return cnt;
8237}
8238
8239static const struct file_operations buffer_percent_fops = {
8240 .open = tracing_open_generic_tr,
8241 .read = buffer_percent_read,
8242 .write = buffer_percent_write,
8243 .release = tracing_release_generic_tr,
8244 .llseek = default_llseek,
8245};
8246
8247static struct dentry *trace_instance_dir;
8248
8249static void
8250init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
8251
8252static int
8253allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
8254{
8255 enum ring_buffer_flags rb_flags;
8256
8257 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
8258
8259 buf->tr = tr;
8260
8261 buf->buffer = ring_buffer_alloc(size, rb_flags);
8262 if (!buf->buffer)
8263 return -ENOMEM;
8264
8265 buf->data = alloc_percpu(struct trace_array_cpu);
8266 if (!buf->data) {
8267 ring_buffer_free(buf->buffer);
8268 buf->buffer = NULL;
8269 return -ENOMEM;
8270 }
8271
8272 /* Allocate the first page for all buffers */
8273 set_buffer_entries(&tr->trace_buffer,
8274 ring_buffer_size(tr->trace_buffer.buffer, 0));
8275
8276 return 0;
8277}
8278
8279static int allocate_trace_buffers(struct trace_array *tr, int size)
8280{
8281 int ret;
8282
8283 ret = allocate_trace_buffer(tr, &tr->trace_buffer, size);
8284 if (ret)
8285 return ret;
8286
8287#ifdef CONFIG_TRACER_MAX_TRACE
8288 ret = allocate_trace_buffer(tr, &tr->max_buffer,
8289 allocate_snapshot ? size : 1);
8290 if (WARN_ON(ret)) {
8291 ring_buffer_free(tr->trace_buffer.buffer);
8292 tr->trace_buffer.buffer = NULL;
8293 free_percpu(tr->trace_buffer.data);
8294 tr->trace_buffer.data = NULL;
8295 return -ENOMEM;
8296 }
8297 tr->allocated_snapshot = allocate_snapshot;
8298
8299 /*
8300 * Only the top level trace array gets its snapshot allocated
8301 * from the kernel command line.
8302 */
8303 allocate_snapshot = false;
8304#endif
8305 return 0;
8306}
8307
8308static void free_trace_buffer(struct trace_buffer *buf)
8309{
8310 if (buf->buffer) {
8311 ring_buffer_free(buf->buffer);
8312 buf->buffer = NULL;
8313 free_percpu(buf->data);
8314 buf->data = NULL;
8315 }
8316}
8317
8318static void free_trace_buffers(struct trace_array *tr)
8319{
8320 if (!tr)
8321 return;
8322
8323 free_trace_buffer(&tr->trace_buffer);
8324
8325#ifdef CONFIG_TRACER_MAX_TRACE
8326 free_trace_buffer(&tr->max_buffer);
8327#endif
8328}
8329
8330static void init_trace_flags_index(struct trace_array *tr)
8331{
8332 int i;
8333
8334 /* Used by the trace options files */
8335 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
8336 tr->trace_flags_index[i] = i;
8337}
8338
8339static void __update_tracer_options(struct trace_array *tr)
8340{
8341 struct tracer *t;
8342
8343 for (t = trace_types; t; t = t->next)
8344 add_tracer_options(tr, t);
8345}
8346
8347static void update_tracer_options(struct trace_array *tr)
8348{
8349 mutex_lock(&trace_types_lock);
8350 __update_tracer_options(tr);
8351 mutex_unlock(&trace_types_lock);
8352}
8353
8354struct trace_array *trace_array_create(const char *name)
8355{
8356 struct trace_array *tr;
8357 int ret;
8358
8359 mutex_lock(&event_mutex);
8360 mutex_lock(&trace_types_lock);
8361
8362 ret = -EEXIST;
8363 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
8364 if (tr->name && strcmp(tr->name, name) == 0)
8365 goto out_unlock;
8366 }
8367
8368 ret = -ENOMEM;
8369 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
8370 if (!tr)
8371 goto out_unlock;
8372
8373 tr->name = kstrdup(name, GFP_KERNEL);
8374 if (!tr->name)
8375 goto out_free_tr;
8376
8377 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
8378 goto out_free_tr;
8379
8380 tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
8381
8382 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
8383
8384 raw_spin_lock_init(&tr->start_lock);
8385
8386 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
8387
8388 tr->current_trace = &nop_trace;
8389
8390 INIT_LIST_HEAD(&tr->systems);
8391 INIT_LIST_HEAD(&tr->events);
8392 INIT_LIST_HEAD(&tr->hist_vars);
8393 INIT_LIST_HEAD(&tr->err_log);
8394
8395 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
8396 goto out_free_tr;
8397
8398 tr->dir = tracefs_create_dir(name, trace_instance_dir);
8399 if (!tr->dir)
8400 goto out_free_tr;
8401
8402 ret = event_trace_add_tracer(tr->dir, tr);
8403 if (ret) {
8404 tracefs_remove_recursive(tr->dir);
8405 goto out_free_tr;
8406 }
8407
8408 ftrace_init_trace_array(tr);
8409
8410 init_tracer_tracefs(tr, tr->dir);
8411 init_trace_flags_index(tr);
8412 __update_tracer_options(tr);
8413
8414 list_add(&tr->list, &ftrace_trace_arrays);
8415
8416 mutex_unlock(&trace_types_lock);
8417 mutex_unlock(&event_mutex);
8418
8419 return tr;
8420
8421 out_free_tr:
8422 free_trace_buffers(tr);
8423 free_cpumask_var(tr->tracing_cpumask);
8424 kfree(tr->name);
8425 kfree(tr);
8426
8427 out_unlock:
8428 mutex_unlock(&trace_types_lock);
8429 mutex_unlock(&event_mutex);
8430
8431 return ERR_PTR(ret);
8432}
8433EXPORT_SYMBOL_GPL(trace_array_create);
8434
8435static int instance_mkdir(const char *name)
8436{
8437 return PTR_ERR_OR_ZERO(trace_array_create(name));
8438}
8439
8440static int __remove_instance(struct trace_array *tr)
8441{
8442 int i;
8443
8444 if (tr->ref || (tr->current_trace && tr->current_trace->ref))
8445 return -EBUSY;
8446
8447 list_del(&tr->list);
8448
8449 /* Disable all the flags that were enabled coming in */
8450 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
8451 if ((1 << i) & ZEROED_TRACE_FLAGS)
8452 set_tracer_flag(tr, 1 << i, 0);
8453 }
8454
8455 tracing_set_nop(tr);
8456 clear_ftrace_function_probes(tr);
8457 event_trace_del_tracer(tr);
8458 ftrace_clear_pids(tr);
8459 ftrace_destroy_function_files(tr);
8460 tracefs_remove_recursive(tr->dir);
8461 free_trace_buffers(tr);
8462
8463 for (i = 0; i < tr->nr_topts; i++) {
8464 kfree(tr->topts[i].topts);
8465 }
8466 kfree(tr->topts);
8467
8468 free_cpumask_var(tr->tracing_cpumask);
8469 kfree(tr->name);
8470 kfree(tr);
8471 tr = NULL;
8472
8473 return 0;
8474}
8475
8476int trace_array_destroy(struct trace_array *tr)
8477{
8478 int ret;
8479
8480 if (!tr)
8481 return -EINVAL;
8482
8483 mutex_lock(&event_mutex);
8484 mutex_lock(&trace_types_lock);
8485
8486 ret = __remove_instance(tr);
8487
8488 mutex_unlock(&trace_types_lock);
8489 mutex_unlock(&event_mutex);
8490
8491 return ret;
8492}
8493EXPORT_SYMBOL_GPL(trace_array_destroy);
8494
8495static int instance_rmdir(const char *name)
8496{
8497 struct trace_array *tr;
8498 int ret;
8499
8500 mutex_lock(&event_mutex);
8501 mutex_lock(&trace_types_lock);
8502
8503 ret = -ENODEV;
8504 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
8505 if (tr->name && strcmp(tr->name, name) == 0) {
8506 ret = __remove_instance(tr);
8507 break;
8508 }
8509 }
8510
8511 mutex_unlock(&trace_types_lock);
8512 mutex_unlock(&event_mutex);
8513
8514 return ret;
8515}
8516
8517static __init void create_trace_instances(struct dentry *d_tracer)
8518{
8519 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
8520 instance_mkdir,
8521 instance_rmdir);
8522 if (WARN_ON(!trace_instance_dir))
8523 return;
8524}
8525
8526static void
8527init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
8528{
8529 struct trace_event_file *file;
8530 int cpu;
8531
8532 trace_create_file("available_tracers", 0444, d_tracer,
8533 tr, &show_traces_fops);
8534
8535 trace_create_file("current_tracer", 0644, d_tracer,
8536 tr, &set_tracer_fops);
8537
8538 trace_create_file("tracing_cpumask", 0644, d_tracer,
8539 tr, &tracing_cpumask_fops);
8540
8541 trace_create_file("trace_options", 0644, d_tracer,
8542 tr, &tracing_iter_fops);
8543
8544 trace_create_file("trace", 0644, d_tracer,
8545 tr, &tracing_fops);
8546
8547 trace_create_file("trace_pipe", 0444, d_tracer,
8548 tr, &tracing_pipe_fops);
8549
8550 trace_create_file("buffer_size_kb", 0644, d_tracer,
8551 tr, &tracing_entries_fops);
8552
8553 trace_create_file("buffer_total_size_kb", 0444, d_tracer,
8554 tr, &tracing_total_entries_fops);
8555
8556 trace_create_file("free_buffer", 0200, d_tracer,
8557 tr, &tracing_free_buffer_fops);
8558
8559 trace_create_file("trace_marker", 0220, d_tracer,
8560 tr, &tracing_mark_fops);
8561
8562 file = __find_event_file(tr, "ftrace", "print");
8563 if (file && file->dir)
8564 trace_create_file("trigger", 0644, file->dir, file,
8565 &event_trigger_fops);
8566 tr->trace_marker_file = file;
8567
8568 trace_create_file("trace_marker_raw", 0220, d_tracer,
8569 tr, &tracing_mark_raw_fops);
8570
8571 trace_create_file("trace_clock", 0644, d_tracer, tr,
8572 &trace_clock_fops);
8573
8574 trace_create_file("tracing_on", 0644, d_tracer,
8575 tr, &rb_simple_fops);
8576
8577 trace_create_file("timestamp_mode", 0444, d_tracer, tr,
8578 &trace_time_stamp_mode_fops);
8579
8580 tr->buffer_percent = 50;
8581
8582 trace_create_file("buffer_percent", 0444, d_tracer,
8583 tr, &buffer_percent_fops);
8584
8585 create_trace_options_dir(tr);
8586
8587#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
8588 trace_create_file("tracing_max_latency", 0644, d_tracer,
8589 &tr->max_latency, &tracing_max_lat_fops);
8590#endif
8591
8592 if (ftrace_create_function_files(tr, d_tracer))
8593 WARN(1, "Could not allocate function filter files");
8594
8595#ifdef CONFIG_TRACER_SNAPSHOT
8596 trace_create_file("snapshot", 0644, d_tracer,
8597 tr, &snapshot_fops);
8598#endif
8599
8600 trace_create_file("error_log", 0644, d_tracer,
8601 tr, &tracing_err_log_fops);
8602
8603 for_each_tracing_cpu(cpu)
8604 tracing_init_tracefs_percpu(tr, cpu);
8605
8606 ftrace_init_tracefs(tr, d_tracer);
8607}
8608
8609static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
8610{
8611 struct vfsmount *mnt;
8612 struct file_system_type *type;
8613
8614 /*
8615 * To maintain backward compatibility for tools that mount
8616 * debugfs to get to the tracing facility, tracefs is automatically
8617 * mounted to the debugfs/tracing directory.
8618 */
8619 type = get_fs_type("tracefs");
8620 if (!type)
8621 return NULL;
8622 mnt = vfs_submount(mntpt, type, "tracefs", NULL);
8623 put_filesystem(type);
8624 if (IS_ERR(mnt))
8625 return NULL;
8626 mntget(mnt);
8627
8628 return mnt;
8629}
8630
8631/**
8632 * tracing_init_dentry - initialize top level trace array
8633 *
8634 * This is called when creating files or directories in the tracing
8635 * directory. It is called via fs_initcall() by any of the boot up code
8636 * and expects to return the dentry of the top level tracing directory.
8637 */
8638struct dentry *tracing_init_dentry(void)
8639{
8640 struct trace_array *tr = &global_trace;
8641
8642 /* The top level trace array uses NULL as parent */
8643 if (tr->dir)
8644 return NULL;
8645
8646 if (WARN_ON(!tracefs_initialized()) ||
8647 (IS_ENABLED(CONFIG_DEBUG_FS) &&
8648 WARN_ON(!debugfs_initialized())))
8649 return ERR_PTR(-ENODEV);
8650
8651 /*
8652 * As there may still be users that expect the tracing
8653 * files to exist in debugfs/tracing, we must automount
8654 * the tracefs file system there, so older tools still
8655 * work with the newer kerenl.
8656 */
8657 tr->dir = debugfs_create_automount("tracing", NULL,
8658 trace_automount, NULL);
8659
8660 return NULL;
8661}
8662
8663extern struct trace_eval_map *__start_ftrace_eval_maps[];
8664extern struct trace_eval_map *__stop_ftrace_eval_maps[];
8665
8666static void __init trace_eval_init(void)
8667{
8668 int len;
8669
8670 len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
8671 trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
8672}
8673
8674#ifdef CONFIG_MODULES
8675static void trace_module_add_evals(struct module *mod)
8676{
8677 if (!mod->num_trace_evals)
8678 return;
8679
8680 /*
8681 * Modules with bad taint do not have events created, do
8682 * not bother with enums either.
8683 */
8684 if (trace_module_has_bad_taint(mod))
8685 return;
8686
8687 trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
8688}
8689
8690#ifdef CONFIG_TRACE_EVAL_MAP_FILE
8691static void trace_module_remove_evals(struct module *mod)
8692{
8693 union trace_eval_map_item *map;
8694 union trace_eval_map_item **last = &trace_eval_maps;
8695
8696 if (!mod->num_trace_evals)
8697 return;
8698
8699 mutex_lock(&trace_eval_mutex);
8700
8701 map = trace_eval_maps;
8702
8703 while (map) {
8704 if (map->head.mod == mod)
8705 break;
8706 map = trace_eval_jmp_to_tail(map);
8707 last = &map->tail.next;
8708 map = map->tail.next;
8709 }
8710 if (!map)
8711 goto out;
8712
8713 *last = trace_eval_jmp_to_tail(map)->tail.next;
8714 kfree(map);
8715 out:
8716 mutex_unlock(&trace_eval_mutex);
8717}
8718#else
8719static inline void trace_module_remove_evals(struct module *mod) { }
8720#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
8721
8722static int trace_module_notify(struct notifier_block *self,
8723 unsigned long val, void *data)
8724{
8725 struct module *mod = data;
8726
8727 switch (val) {
8728 case MODULE_STATE_COMING:
8729 trace_module_add_evals(mod);
8730 break;
8731 case MODULE_STATE_GOING:
8732 trace_module_remove_evals(mod);
8733 break;
8734 }
8735
8736 return 0;
8737}
8738
8739static struct notifier_block trace_module_nb = {
8740 .notifier_call = trace_module_notify,
8741 .priority = 0,
8742};
8743#endif /* CONFIG_MODULES */
8744
8745static __init int tracer_init_tracefs(void)
8746{
8747 struct dentry *d_tracer;
8748
8749 trace_access_lock_init();
8750
8751 d_tracer = tracing_init_dentry();
8752 if (IS_ERR(d_tracer))
8753 return 0;
8754
8755 event_trace_init();
8756
8757 init_tracer_tracefs(&global_trace, d_tracer);
8758 ftrace_init_tracefs_toplevel(&global_trace, d_tracer);
8759
8760 trace_create_file("tracing_thresh", 0644, d_tracer,
8761 &global_trace, &tracing_thresh_fops);
8762
8763 trace_create_file("README", 0444, d_tracer,
8764 NULL, &tracing_readme_fops);
8765
8766 trace_create_file("saved_cmdlines", 0444, d_tracer,
8767 NULL, &tracing_saved_cmdlines_fops);
8768
8769 trace_create_file("saved_cmdlines_size", 0644, d_tracer,
8770 NULL, &tracing_saved_cmdlines_size_fops);
8771
8772 trace_create_file("saved_tgids", 0444, d_tracer,
8773 NULL, &tracing_saved_tgids_fops);
8774
8775 trace_eval_init();
8776
8777 trace_create_eval_file(d_tracer);
8778
8779#ifdef CONFIG_MODULES
8780 register_module_notifier(&trace_module_nb);
8781#endif
8782
8783#ifdef CONFIG_DYNAMIC_FTRACE
8784 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
8785 &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
8786#endif
8787
8788 create_trace_instances(d_tracer);
8789
8790 update_tracer_options(&global_trace);
8791
8792 return 0;
8793}
8794
8795static int trace_panic_handler(struct notifier_block *this,
8796 unsigned long event, void *unused)
8797{
8798 if (ftrace_dump_on_oops)
8799 ftrace_dump(ftrace_dump_on_oops);
8800 return NOTIFY_OK;
8801}
8802
8803static struct notifier_block trace_panic_notifier = {
8804 .notifier_call = trace_panic_handler,
8805 .next = NULL,
8806 .priority = 150 /* priority: INT_MAX >= x >= 0 */
8807};
8808
8809static int trace_die_handler(struct notifier_block *self,
8810 unsigned long val,
8811 void *data)
8812{
8813 switch (val) {
8814 case DIE_OOPS:
8815 if (ftrace_dump_on_oops)
8816 ftrace_dump(ftrace_dump_on_oops);
8817 break;
8818 default:
8819 break;
8820 }
8821 return NOTIFY_OK;
8822}
8823
8824static struct notifier_block trace_die_notifier = {
8825 .notifier_call = trace_die_handler,
8826 .priority = 200
8827};
8828
8829/*
8830 * printk is set to max of 1024, we really don't need it that big.
8831 * Nothing should be printing 1000 characters anyway.
8832 */
8833#define TRACE_MAX_PRINT 1000
8834
8835/*
8836 * Define here KERN_TRACE so that we have one place to modify
8837 * it if we decide to change what log level the ftrace dump
8838 * should be at.
8839 */
8840#define KERN_TRACE KERN_EMERG
8841
8842void
8843trace_printk_seq(struct trace_seq *s)
8844{
8845 /* Probably should print a warning here. */
8846 if (s->seq.len >= TRACE_MAX_PRINT)
8847 s->seq.len = TRACE_MAX_PRINT;
8848
8849 /*
8850 * More paranoid code. Although the buffer size is set to
8851 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
8852 * an extra layer of protection.
8853 */
8854 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
8855 s->seq.len = s->seq.size - 1;
8856
8857 /* should be zero ended, but we are paranoid. */
8858 s->buffer[s->seq.len] = 0;
8859
8860 printk(KERN_TRACE "%s", s->buffer);
8861
8862 trace_seq_init(s);
8863}
8864
8865void trace_init_global_iter(struct trace_iterator *iter)
8866{
8867 iter->tr = &global_trace;
8868 iter->trace = iter->tr->current_trace;
8869 iter->cpu_file = RING_BUFFER_ALL_CPUS;
8870 iter->trace_buffer = &global_trace.trace_buffer;
8871
8872 if (iter->trace && iter->trace->open)
8873 iter->trace->open(iter);
8874
8875 /* Annotate start of buffers if we had overruns */
8876 if (ring_buffer_overruns(iter->trace_buffer->buffer))
8877 iter->iter_flags |= TRACE_FILE_ANNOTATE;
8878
8879 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
8880 if (trace_clocks[iter->tr->clock_id].in_ns)
8881 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
8882}
8883
8884void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
8885{
8886 /* use static because iter can be a bit big for the stack */
8887 static struct trace_iterator iter;
8888 static atomic_t dump_running;
8889 struct trace_array *tr = &global_trace;
8890 unsigned int old_userobj;
8891 unsigned long flags;
8892 int cnt = 0, cpu;
8893
8894 /* Only allow one dump user at a time. */
8895 if (atomic_inc_return(&dump_running) != 1) {
8896 atomic_dec(&dump_running);
8897 return;
8898 }
8899
8900 /*
8901 * Always turn off tracing when we dump.
8902 * We don't need to show trace output of what happens
8903 * between multiple crashes.
8904 *
8905 * If the user does a sysrq-z, then they can re-enable
8906 * tracing with echo 1 > tracing_on.
8907 */
8908 tracing_off();
8909
8910 local_irq_save(flags);
8911 printk_nmi_direct_enter();
8912
8913 /* Simulate the iterator */
8914 trace_init_global_iter(&iter);
8915
8916 for_each_tracing_cpu(cpu) {
8917 atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
8918 }
8919
8920 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
8921
8922 /* don't look at user memory in panic mode */
8923 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
8924
8925 switch (oops_dump_mode) {
8926 case DUMP_ALL:
8927 iter.cpu_file = RING_BUFFER_ALL_CPUS;
8928 break;
8929 case DUMP_ORIG:
8930 iter.cpu_file = raw_smp_processor_id();
8931 break;
8932 case DUMP_NONE:
8933 goto out_enable;
8934 default:
8935 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
8936 iter.cpu_file = RING_BUFFER_ALL_CPUS;
8937 }
8938
8939 printk(KERN_TRACE "Dumping ftrace buffer:\n");
8940
8941 /* Did function tracer already get disabled? */
8942 if (ftrace_is_dead()) {
8943 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
8944 printk("# MAY BE MISSING FUNCTION EVENTS\n");
8945 }
8946
8947 /*
8948 * We need to stop all tracing on all CPUS to read the
8949 * the next buffer. This is a bit expensive, but is
8950 * not done often. We fill all what we can read,
8951 * and then release the locks again.
8952 */
8953
8954 while (!trace_empty(&iter)) {
8955
8956 if (!cnt)
8957 printk(KERN_TRACE "---------------------------------\n");
8958
8959 cnt++;
8960
8961 trace_iterator_reset(&iter);
8962 iter.iter_flags |= TRACE_FILE_LAT_FMT;
8963
8964 if (trace_find_next_entry_inc(&iter) != NULL) {
8965 int ret;
8966
8967 ret = print_trace_line(&iter);
8968 if (ret != TRACE_TYPE_NO_CONSUME)
8969 trace_consume(&iter);
8970 }
8971 touch_nmi_watchdog();
8972
8973 trace_printk_seq(&iter.seq);
8974 }
8975
8976 if (!cnt)
8977 printk(KERN_TRACE " (ftrace buffer empty)\n");
8978 else
8979 printk(KERN_TRACE "---------------------------------\n");
8980
8981 out_enable:
8982 tr->trace_flags |= old_userobj;
8983
8984 for_each_tracing_cpu(cpu) {
8985 atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
8986 }
8987 atomic_dec(&dump_running);
8988 printk_nmi_direct_exit();
8989 local_irq_restore(flags);
8990}
8991EXPORT_SYMBOL_GPL(ftrace_dump);
8992
8993int trace_run_command(const char *buf, int (*createfn)(int, char **))
8994{
8995 char **argv;
8996 int argc, ret;
8997
8998 argc = 0;
8999 ret = 0;
9000 argv = argv_split(GFP_KERNEL, buf, &argc);
9001 if (!argv)
9002 return -ENOMEM;
9003
9004 if (argc)
9005 ret = createfn(argc, argv);
9006
9007 argv_free(argv);
9008
9009 return ret;
9010}
9011
9012#define WRITE_BUFSIZE 4096
9013
9014ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
9015 size_t count, loff_t *ppos,
9016 int (*createfn)(int, char **))
9017{
9018 char *kbuf, *buf, *tmp;
9019 int ret = 0;
9020 size_t done = 0;
9021 size_t size;
9022
9023 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
9024 if (!kbuf)
9025 return -ENOMEM;
9026
9027 while (done < count) {
9028 size = count - done;
9029
9030 if (size >= WRITE_BUFSIZE)
9031 size = WRITE_BUFSIZE - 1;
9032
9033 if (copy_from_user(kbuf, buffer + done, size)) {
9034 ret = -EFAULT;
9035 goto out;
9036 }
9037 kbuf[size] = '\0';
9038 buf = kbuf;
9039 do {
9040 tmp = strchr(buf, '\n');
9041 if (tmp) {
9042 *tmp = '\0';
9043 size = tmp - buf + 1;
9044 } else {
9045 size = strlen(buf);
9046 if (done + size < count) {
9047 if (buf != kbuf)
9048 break;
9049 /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
9050 pr_warn("Line length is too long: Should be less than %d\n",
9051 WRITE_BUFSIZE - 2);
9052 ret = -EINVAL;
9053 goto out;
9054 }
9055 }
9056 done += size;
9057
9058 /* Remove comments */
9059 tmp = strchr(buf, '#');
9060
9061 if (tmp)
9062 *tmp = '\0';
9063
9064 ret = trace_run_command(buf, createfn);
9065 if (ret)
9066 goto out;
9067 buf += size;
9068
9069 } while (done < count);
9070 }
9071 ret = done;
9072
9073out:
9074 kfree(kbuf);
9075
9076 return ret;
9077}
9078
9079__init static int tracer_alloc_buffers(void)
9080{
9081 int ring_buf_size;
9082 int ret = -ENOMEM;
9083
9084 /*
9085 * Make sure we don't accidently add more trace options
9086 * than we have bits for.
9087 */
9088 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
9089
9090 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
9091 goto out;
9092
9093 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
9094 goto out_free_buffer_mask;
9095
9096 /* Only allocate trace_printk buffers if a trace_printk exists */
9097 if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
9098 /* Must be called before global_trace.buffer is allocated */
9099 trace_printk_init_buffers();
9100
9101 /* To save memory, keep the ring buffer size to its minimum */
9102 if (ring_buffer_expanded)
9103 ring_buf_size = trace_buf_size;
9104 else
9105 ring_buf_size = 1;
9106
9107 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
9108 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
9109
9110 raw_spin_lock_init(&global_trace.start_lock);
9111
9112 /*
9113 * The prepare callbacks allocates some memory for the ring buffer. We
9114 * don't free the buffer if the if the CPU goes down. If we were to free
9115 * the buffer, then the user would lose any trace that was in the
9116 * buffer. The memory will be removed once the "instance" is removed.
9117 */
9118 ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
9119 "trace/RB:preapre", trace_rb_cpu_prepare,
9120 NULL);
9121 if (ret < 0)
9122 goto out_free_cpumask;
9123 /* Used for event triggers */
9124 ret = -ENOMEM;
9125 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
9126 if (!temp_buffer)
9127 goto out_rm_hp_state;
9128
9129 if (trace_create_savedcmd() < 0)
9130 goto out_free_temp_buffer;
9131
9132 /* TODO: make the number of buffers hot pluggable with CPUS */
9133 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
9134 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
9135 WARN_ON(1);
9136 goto out_free_savedcmd;
9137 }
9138
9139 if (global_trace.buffer_disabled)
9140 tracing_off();
9141
9142 if (trace_boot_clock) {
9143 ret = tracing_set_clock(&global_trace, trace_boot_clock);
9144 if (ret < 0)
9145 pr_warn("Trace clock %s not defined, going back to default\n",
9146 trace_boot_clock);
9147 }
9148
9149 /*
9150 * register_tracer() might reference current_trace, so it
9151 * needs to be set before we register anything. This is
9152 * just a bootstrap of current_trace anyway.
9153 */
9154 global_trace.current_trace = &nop_trace;
9155
9156 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
9157
9158 ftrace_init_global_array_ops(&global_trace);
9159
9160 init_trace_flags_index(&global_trace);
9161
9162 register_tracer(&nop_trace);
9163
9164 /* Function tracing may start here (via kernel command line) */
9165 init_function_trace();
9166
9167 /* All seems OK, enable tracing */
9168 tracing_disabled = 0;
9169
9170 atomic_notifier_chain_register(&panic_notifier_list,
9171 &trace_panic_notifier);
9172
9173 register_die_notifier(&trace_die_notifier);
9174
9175 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
9176
9177 INIT_LIST_HEAD(&global_trace.systems);
9178 INIT_LIST_HEAD(&global_trace.events);
9179 INIT_LIST_HEAD(&global_trace.hist_vars);
9180 INIT_LIST_HEAD(&global_trace.err_log);
9181 list_add(&global_trace.list, &ftrace_trace_arrays);
9182
9183 apply_trace_boot_options();
9184
9185 register_snapshot_cmd();
9186
9187 return 0;
9188
9189out_free_savedcmd:
9190 free_saved_cmdlines_buffer(savedcmd);
9191out_free_temp_buffer:
9192 ring_buffer_free(temp_buffer);
9193out_rm_hp_state:
9194 cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
9195out_free_cpumask:
9196 free_cpumask_var(global_trace.tracing_cpumask);
9197out_free_buffer_mask:
9198 free_cpumask_var(tracing_buffer_mask);
9199out:
9200 return ret;
9201}
9202
9203void __init early_trace_init(void)
9204{
9205 if (tracepoint_printk) {
9206 tracepoint_print_iter =
9207 kmalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
9208 if (WARN_ON(!tracepoint_print_iter))
9209 tracepoint_printk = 0;
9210 else
9211 static_key_enable(&tracepoint_printk_key.key);
9212 }
9213 tracer_alloc_buffers();
9214}
9215
9216void __init trace_init(void)
9217{
9218 trace_event_init();
9219}
9220
9221__init static int clear_boot_tracer(void)
9222{
9223 /*
9224 * The default tracer at boot buffer is an init section.
9225 * This function is called in lateinit. If we did not
9226 * find the boot tracer, then clear it out, to prevent
9227 * later registration from accessing the buffer that is
9228 * about to be freed.
9229 */
9230 if (!default_bootup_tracer)
9231 return 0;
9232
9233 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
9234 default_bootup_tracer);
9235 default_bootup_tracer = NULL;
9236
9237 return 0;
9238}
9239
9240fs_initcall(tracer_init_tracefs);
9241late_initcall_sync(clear_boot_tracer);
9242
9243#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
9244__init static int tracing_set_default_clock(void)
9245{
9246 /* sched_clock_stable() is determined in late_initcall */
9247 if (!trace_boot_clock && !sched_clock_stable()) {
9248 printk(KERN_WARNING
9249 "Unstable clock detected, switching default tracing clock to \"global\"\n"
9250 "If you want to keep using the local clock, then add:\n"
9251 " \"trace_clock=local\"\n"
9252 "on the kernel command line\n");
9253 tracing_set_clock(&global_trace, "global");
9254 }
9255
9256 return 0;
9257}
9258late_initcall_sync(tracing_set_default_clock);
9259#endif