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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 <linux/utsname.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/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#include <linux/fsnotify.h>
49#include <linux/irq_work.h>
50#include <linux/workqueue.h>
51
52#include <asm/setup.h> /* COMMAND_LINE_SIZE */
53
54#include "trace.h"
55#include "trace_output.h"
56
57#ifdef CONFIG_FTRACE_STARTUP_TEST
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 boot-time tracing including tracers/events via kernel cmdline
69 * is running, we do not want to run SELFTEST.
70 */
71bool __read_mostly tracing_selftest_disabled;
72
73void __init disable_tracing_selftest(const char *reason)
74{
75 if (!tracing_selftest_disabled) {
76 tracing_selftest_disabled = true;
77 pr_info("Ftrace startup test is disabled due to %s\n", reason);
78 }
79}
80#else
81#define tracing_selftest_running 0
82#define tracing_selftest_disabled 0
83#endif
84
85/* Pipe tracepoints to printk */
86static struct trace_iterator *tracepoint_print_iter;
87int tracepoint_printk;
88static bool tracepoint_printk_stop_on_boot __initdata;
89static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
90
91/* For tracers that don't implement custom flags */
92static struct tracer_opt dummy_tracer_opt[] = {
93 { }
94};
95
96static int
97dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
98{
99 return 0;
100}
101
102/*
103 * To prevent the comm cache from being overwritten when no
104 * tracing is active, only save the comm when a trace event
105 * occurred.
106 */
107DEFINE_PER_CPU(bool, trace_taskinfo_save);
108
109/*
110 * Kill all tracing for good (never come back).
111 * It is initialized to 1 but will turn to zero if the initialization
112 * of the tracer is successful. But that is the only place that sets
113 * this back to zero.
114 */
115static int tracing_disabled = 1;
116
117cpumask_var_t __read_mostly tracing_buffer_mask;
118
119/*
120 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
121 *
122 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
123 * is set, then ftrace_dump is called. This will output the contents
124 * of the ftrace buffers to the console. This is very useful for
125 * capturing traces that lead to crashes and outputing it to a
126 * serial console.
127 *
128 * It is default off, but you can enable it with either specifying
129 * "ftrace_dump_on_oops" in the kernel command line, or setting
130 * /proc/sys/kernel/ftrace_dump_on_oops
131 * Set 1 if you want to dump buffers of all CPUs
132 * Set 2 if you want to dump the buffer of the CPU that triggered oops
133 * Set instance name if you want to dump the specific trace instance
134 * Multiple instance dump is also supported, and instances are seperated
135 * by commas.
136 */
137/* Set to string format zero to disable by default */
138char ftrace_dump_on_oops[MAX_TRACER_SIZE] = "0";
139
140/* When set, tracing will stop when a WARN*() is hit */
141int __disable_trace_on_warning;
142
143#ifdef CONFIG_TRACE_EVAL_MAP_FILE
144/* Map of enums to their values, for "eval_map" file */
145struct trace_eval_map_head {
146 struct module *mod;
147 unsigned long length;
148};
149
150union trace_eval_map_item;
151
152struct trace_eval_map_tail {
153 /*
154 * "end" is first and points to NULL as it must be different
155 * than "mod" or "eval_string"
156 */
157 union trace_eval_map_item *next;
158 const char *end; /* points to NULL */
159};
160
161static DEFINE_MUTEX(trace_eval_mutex);
162
163/*
164 * The trace_eval_maps are saved in an array with two extra elements,
165 * one at the beginning, and one at the end. The beginning item contains
166 * the count of the saved maps (head.length), and the module they
167 * belong to if not built in (head.mod). The ending item contains a
168 * pointer to the next array of saved eval_map items.
169 */
170union trace_eval_map_item {
171 struct trace_eval_map map;
172 struct trace_eval_map_head head;
173 struct trace_eval_map_tail tail;
174};
175
176static union trace_eval_map_item *trace_eval_maps;
177#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
178
179int tracing_set_tracer(struct trace_array *tr, const char *buf);
180static void ftrace_trace_userstack(struct trace_array *tr,
181 struct trace_buffer *buffer,
182 unsigned int trace_ctx);
183
184static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
185static char *default_bootup_tracer;
186
187static bool allocate_snapshot;
188static bool snapshot_at_boot;
189
190static char boot_instance_info[COMMAND_LINE_SIZE] __initdata;
191static int boot_instance_index;
192
193static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata;
194static int boot_snapshot_index;
195
196static int __init set_cmdline_ftrace(char *str)
197{
198 strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
199 default_bootup_tracer = bootup_tracer_buf;
200 /* We are using ftrace early, expand it */
201 trace_set_ring_buffer_expanded(NULL);
202 return 1;
203}
204__setup("ftrace=", set_cmdline_ftrace);
205
206int ftrace_dump_on_oops_enabled(void)
207{
208 if (!strcmp("0", ftrace_dump_on_oops))
209 return 0;
210 else
211 return 1;
212}
213
214static int __init set_ftrace_dump_on_oops(char *str)
215{
216 if (!*str) {
217 strscpy(ftrace_dump_on_oops, "1", MAX_TRACER_SIZE);
218 return 1;
219 }
220
221 if (*str == ',') {
222 strscpy(ftrace_dump_on_oops, "1", MAX_TRACER_SIZE);
223 strscpy(ftrace_dump_on_oops + 1, str, MAX_TRACER_SIZE - 1);
224 return 1;
225 }
226
227 if (*str++ == '=') {
228 strscpy(ftrace_dump_on_oops, str, MAX_TRACER_SIZE);
229 return 1;
230 }
231
232 return 0;
233}
234__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
235
236static int __init stop_trace_on_warning(char *str)
237{
238 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
239 __disable_trace_on_warning = 1;
240 return 1;
241}
242__setup("traceoff_on_warning", stop_trace_on_warning);
243
244static int __init boot_alloc_snapshot(char *str)
245{
246 char *slot = boot_snapshot_info + boot_snapshot_index;
247 int left = sizeof(boot_snapshot_info) - boot_snapshot_index;
248 int ret;
249
250 if (str[0] == '=') {
251 str++;
252 if (strlen(str) >= left)
253 return -1;
254
255 ret = snprintf(slot, left, "%s\t", str);
256 boot_snapshot_index += ret;
257 } else {
258 allocate_snapshot = true;
259 /* We also need the main ring buffer expanded */
260 trace_set_ring_buffer_expanded(NULL);
261 }
262 return 1;
263}
264__setup("alloc_snapshot", boot_alloc_snapshot);
265
266
267static int __init boot_snapshot(char *str)
268{
269 snapshot_at_boot = true;
270 boot_alloc_snapshot(str);
271 return 1;
272}
273__setup("ftrace_boot_snapshot", boot_snapshot);
274
275
276static int __init boot_instance(char *str)
277{
278 char *slot = boot_instance_info + boot_instance_index;
279 int left = sizeof(boot_instance_info) - boot_instance_index;
280 int ret;
281
282 if (strlen(str) >= left)
283 return -1;
284
285 ret = snprintf(slot, left, "%s\t", str);
286 boot_instance_index += ret;
287
288 return 1;
289}
290__setup("trace_instance=", boot_instance);
291
292
293static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
294
295static int __init set_trace_boot_options(char *str)
296{
297 strscpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
298 return 1;
299}
300__setup("trace_options=", set_trace_boot_options);
301
302static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
303static char *trace_boot_clock __initdata;
304
305static int __init set_trace_boot_clock(char *str)
306{
307 strscpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
308 trace_boot_clock = trace_boot_clock_buf;
309 return 1;
310}
311__setup("trace_clock=", set_trace_boot_clock);
312
313static int __init set_tracepoint_printk(char *str)
314{
315 /* Ignore the "tp_printk_stop_on_boot" param */
316 if (*str == '_')
317 return 0;
318
319 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
320 tracepoint_printk = 1;
321 return 1;
322}
323__setup("tp_printk", set_tracepoint_printk);
324
325static int __init set_tracepoint_printk_stop(char *str)
326{
327 tracepoint_printk_stop_on_boot = true;
328 return 1;
329}
330__setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop);
331
332unsigned long long ns2usecs(u64 nsec)
333{
334 nsec += 500;
335 do_div(nsec, 1000);
336 return nsec;
337}
338
339static void
340trace_process_export(struct trace_export *export,
341 struct ring_buffer_event *event, int flag)
342{
343 struct trace_entry *entry;
344 unsigned int size = 0;
345
346 if (export->flags & flag) {
347 entry = ring_buffer_event_data(event);
348 size = ring_buffer_event_length(event);
349 export->write(export, entry, size);
350 }
351}
352
353static DEFINE_MUTEX(ftrace_export_lock);
354
355static struct trace_export __rcu *ftrace_exports_list __read_mostly;
356
357static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled);
358static DEFINE_STATIC_KEY_FALSE(trace_event_exports_enabled);
359static DEFINE_STATIC_KEY_FALSE(trace_marker_exports_enabled);
360
361static inline void ftrace_exports_enable(struct trace_export *export)
362{
363 if (export->flags & TRACE_EXPORT_FUNCTION)
364 static_branch_inc(&trace_function_exports_enabled);
365
366 if (export->flags & TRACE_EXPORT_EVENT)
367 static_branch_inc(&trace_event_exports_enabled);
368
369 if (export->flags & TRACE_EXPORT_MARKER)
370 static_branch_inc(&trace_marker_exports_enabled);
371}
372
373static inline void ftrace_exports_disable(struct trace_export *export)
374{
375 if (export->flags & TRACE_EXPORT_FUNCTION)
376 static_branch_dec(&trace_function_exports_enabled);
377
378 if (export->flags & TRACE_EXPORT_EVENT)
379 static_branch_dec(&trace_event_exports_enabled);
380
381 if (export->flags & TRACE_EXPORT_MARKER)
382 static_branch_dec(&trace_marker_exports_enabled);
383}
384
385static void ftrace_exports(struct ring_buffer_event *event, int flag)
386{
387 struct trace_export *export;
388
389 preempt_disable_notrace();
390
391 export = rcu_dereference_raw_check(ftrace_exports_list);
392 while (export) {
393 trace_process_export(export, event, flag);
394 export = rcu_dereference_raw_check(export->next);
395 }
396
397 preempt_enable_notrace();
398}
399
400static inline void
401add_trace_export(struct trace_export **list, struct trace_export *export)
402{
403 rcu_assign_pointer(export->next, *list);
404 /*
405 * We are entering export into the list but another
406 * CPU might be walking that list. We need to make sure
407 * the export->next pointer is valid before another CPU sees
408 * the export pointer included into the list.
409 */
410 rcu_assign_pointer(*list, export);
411}
412
413static inline int
414rm_trace_export(struct trace_export **list, struct trace_export *export)
415{
416 struct trace_export **p;
417
418 for (p = list; *p != NULL; p = &(*p)->next)
419 if (*p == export)
420 break;
421
422 if (*p != export)
423 return -1;
424
425 rcu_assign_pointer(*p, (*p)->next);
426
427 return 0;
428}
429
430static inline void
431add_ftrace_export(struct trace_export **list, struct trace_export *export)
432{
433 ftrace_exports_enable(export);
434
435 add_trace_export(list, export);
436}
437
438static inline int
439rm_ftrace_export(struct trace_export **list, struct trace_export *export)
440{
441 int ret;
442
443 ret = rm_trace_export(list, export);
444 ftrace_exports_disable(export);
445
446 return ret;
447}
448
449int register_ftrace_export(struct trace_export *export)
450{
451 if (WARN_ON_ONCE(!export->write))
452 return -1;
453
454 mutex_lock(&ftrace_export_lock);
455
456 add_ftrace_export(&ftrace_exports_list, export);
457
458 mutex_unlock(&ftrace_export_lock);
459
460 return 0;
461}
462EXPORT_SYMBOL_GPL(register_ftrace_export);
463
464int unregister_ftrace_export(struct trace_export *export)
465{
466 int ret;
467
468 mutex_lock(&ftrace_export_lock);
469
470 ret = rm_ftrace_export(&ftrace_exports_list, export);
471
472 mutex_unlock(&ftrace_export_lock);
473
474 return ret;
475}
476EXPORT_SYMBOL_GPL(unregister_ftrace_export);
477
478/* trace_flags holds trace_options default values */
479#define TRACE_DEFAULT_FLAGS \
480 (FUNCTION_DEFAULT_FLAGS | \
481 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
482 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
483 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
484 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | \
485 TRACE_ITER_HASH_PTR)
486
487/* trace_options that are only supported by global_trace */
488#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
489 TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
490
491/* trace_flags that are default zero for instances */
492#define ZEROED_TRACE_FLAGS \
493 (TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK)
494
495/*
496 * The global_trace is the descriptor that holds the top-level tracing
497 * buffers for the live tracing.
498 */
499static struct trace_array global_trace = {
500 .trace_flags = TRACE_DEFAULT_FLAGS,
501};
502
503void trace_set_ring_buffer_expanded(struct trace_array *tr)
504{
505 if (!tr)
506 tr = &global_trace;
507 tr->ring_buffer_expanded = true;
508}
509
510LIST_HEAD(ftrace_trace_arrays);
511
512int trace_array_get(struct trace_array *this_tr)
513{
514 struct trace_array *tr;
515 int ret = -ENODEV;
516
517 mutex_lock(&trace_types_lock);
518 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
519 if (tr == this_tr) {
520 tr->ref++;
521 ret = 0;
522 break;
523 }
524 }
525 mutex_unlock(&trace_types_lock);
526
527 return ret;
528}
529
530static void __trace_array_put(struct trace_array *this_tr)
531{
532 WARN_ON(!this_tr->ref);
533 this_tr->ref--;
534}
535
536/**
537 * trace_array_put - Decrement the reference counter for this trace array.
538 * @this_tr : pointer to the trace array
539 *
540 * NOTE: Use this when we no longer need the trace array returned by
541 * trace_array_get_by_name(). This ensures the trace array can be later
542 * destroyed.
543 *
544 */
545void trace_array_put(struct trace_array *this_tr)
546{
547 if (!this_tr)
548 return;
549
550 mutex_lock(&trace_types_lock);
551 __trace_array_put(this_tr);
552 mutex_unlock(&trace_types_lock);
553}
554EXPORT_SYMBOL_GPL(trace_array_put);
555
556int tracing_check_open_get_tr(struct trace_array *tr)
557{
558 int ret;
559
560 ret = security_locked_down(LOCKDOWN_TRACEFS);
561 if (ret)
562 return ret;
563
564 if (tracing_disabled)
565 return -ENODEV;
566
567 if (tr && trace_array_get(tr) < 0)
568 return -ENODEV;
569
570 return 0;
571}
572
573int call_filter_check_discard(struct trace_event_call *call, void *rec,
574 struct trace_buffer *buffer,
575 struct ring_buffer_event *event)
576{
577 if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
578 !filter_match_preds(call->filter, rec)) {
579 __trace_event_discard_commit(buffer, event);
580 return 1;
581 }
582
583 return 0;
584}
585
586/**
587 * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
588 * @filtered_pids: The list of pids to check
589 * @search_pid: The PID to find in @filtered_pids
590 *
591 * Returns true if @search_pid is found in @filtered_pids, and false otherwise.
592 */
593bool
594trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
595{
596 return trace_pid_list_is_set(filtered_pids, search_pid);
597}
598
599/**
600 * trace_ignore_this_task - should a task be ignored for tracing
601 * @filtered_pids: The list of pids to check
602 * @filtered_no_pids: The list of pids not to be traced
603 * @task: The task that should be ignored if not filtered
604 *
605 * Checks if @task should be traced or not from @filtered_pids.
606 * Returns true if @task should *NOT* be traced.
607 * Returns false if @task should be traced.
608 */
609bool
610trace_ignore_this_task(struct trace_pid_list *filtered_pids,
611 struct trace_pid_list *filtered_no_pids,
612 struct task_struct *task)
613{
614 /*
615 * If filtered_no_pids is not empty, and the task's pid is listed
616 * in filtered_no_pids, then return true.
617 * Otherwise, if filtered_pids is empty, that means we can
618 * trace all tasks. If it has content, then only trace pids
619 * within filtered_pids.
620 */
621
622 return (filtered_pids &&
623 !trace_find_filtered_pid(filtered_pids, task->pid)) ||
624 (filtered_no_pids &&
625 trace_find_filtered_pid(filtered_no_pids, task->pid));
626}
627
628/**
629 * trace_filter_add_remove_task - Add or remove a task from a pid_list
630 * @pid_list: The list to modify
631 * @self: The current task for fork or NULL for exit
632 * @task: The task to add or remove
633 *
634 * If adding a task, if @self is defined, the task is only added if @self
635 * is also included in @pid_list. This happens on fork and tasks should
636 * only be added when the parent is listed. If @self is NULL, then the
637 * @task pid will be removed from the list, which would happen on exit
638 * of a task.
639 */
640void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
641 struct task_struct *self,
642 struct task_struct *task)
643{
644 if (!pid_list)
645 return;
646
647 /* For forks, we only add if the forking task is listed */
648 if (self) {
649 if (!trace_find_filtered_pid(pid_list, self->pid))
650 return;
651 }
652
653 /* "self" is set for forks, and NULL for exits */
654 if (self)
655 trace_pid_list_set(pid_list, task->pid);
656 else
657 trace_pid_list_clear(pid_list, task->pid);
658}
659
660/**
661 * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
662 * @pid_list: The pid list to show
663 * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
664 * @pos: The position of the file
665 *
666 * This is used by the seq_file "next" operation to iterate the pids
667 * listed in a trace_pid_list structure.
668 *
669 * Returns the pid+1 as we want to display pid of zero, but NULL would
670 * stop the iteration.
671 */
672void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
673{
674 long pid = (unsigned long)v;
675 unsigned int next;
676
677 (*pos)++;
678
679 /* pid already is +1 of the actual previous bit */
680 if (trace_pid_list_next(pid_list, pid, &next) < 0)
681 return NULL;
682
683 pid = next;
684
685 /* Return pid + 1 to allow zero to be represented */
686 return (void *)(pid + 1);
687}
688
689/**
690 * trace_pid_start - Used for seq_file to start reading pid lists
691 * @pid_list: The pid list to show
692 * @pos: The position of the file
693 *
694 * This is used by seq_file "start" operation to start the iteration
695 * of listing pids.
696 *
697 * Returns the pid+1 as we want to display pid of zero, but NULL would
698 * stop the iteration.
699 */
700void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
701{
702 unsigned long pid;
703 unsigned int first;
704 loff_t l = 0;
705
706 if (trace_pid_list_first(pid_list, &first) < 0)
707 return NULL;
708
709 pid = first;
710
711 /* Return pid + 1 so that zero can be the exit value */
712 for (pid++; pid && l < *pos;
713 pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
714 ;
715 return (void *)pid;
716}
717
718/**
719 * trace_pid_show - show the current pid in seq_file processing
720 * @m: The seq_file structure to write into
721 * @v: A void pointer of the pid (+1) value to display
722 *
723 * Can be directly used by seq_file operations to display the current
724 * pid value.
725 */
726int trace_pid_show(struct seq_file *m, void *v)
727{
728 unsigned long pid = (unsigned long)v - 1;
729
730 seq_printf(m, "%lu\n", pid);
731 return 0;
732}
733
734/* 128 should be much more than enough */
735#define PID_BUF_SIZE 127
736
737int trace_pid_write(struct trace_pid_list *filtered_pids,
738 struct trace_pid_list **new_pid_list,
739 const char __user *ubuf, size_t cnt)
740{
741 struct trace_pid_list *pid_list;
742 struct trace_parser parser;
743 unsigned long val;
744 int nr_pids = 0;
745 ssize_t read = 0;
746 ssize_t ret;
747 loff_t pos;
748 pid_t pid;
749
750 if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
751 return -ENOMEM;
752
753 /*
754 * Always recreate a new array. The write is an all or nothing
755 * operation. Always create a new array when adding new pids by
756 * the user. If the operation fails, then the current list is
757 * not modified.
758 */
759 pid_list = trace_pid_list_alloc();
760 if (!pid_list) {
761 trace_parser_put(&parser);
762 return -ENOMEM;
763 }
764
765 if (filtered_pids) {
766 /* copy the current bits to the new max */
767 ret = trace_pid_list_first(filtered_pids, &pid);
768 while (!ret) {
769 trace_pid_list_set(pid_list, pid);
770 ret = trace_pid_list_next(filtered_pids, pid + 1, &pid);
771 nr_pids++;
772 }
773 }
774
775 ret = 0;
776 while (cnt > 0) {
777
778 pos = 0;
779
780 ret = trace_get_user(&parser, ubuf, cnt, &pos);
781 if (ret < 0)
782 break;
783
784 read += ret;
785 ubuf += ret;
786 cnt -= ret;
787
788 if (!trace_parser_loaded(&parser))
789 break;
790
791 ret = -EINVAL;
792 if (kstrtoul(parser.buffer, 0, &val))
793 break;
794
795 pid = (pid_t)val;
796
797 if (trace_pid_list_set(pid_list, pid) < 0) {
798 ret = -1;
799 break;
800 }
801 nr_pids++;
802
803 trace_parser_clear(&parser);
804 ret = 0;
805 }
806 trace_parser_put(&parser);
807
808 if (ret < 0) {
809 trace_pid_list_free(pid_list);
810 return ret;
811 }
812
813 if (!nr_pids) {
814 /* Cleared the list of pids */
815 trace_pid_list_free(pid_list);
816 pid_list = NULL;
817 }
818
819 *new_pid_list = pid_list;
820
821 return read;
822}
823
824static u64 buffer_ftrace_now(struct array_buffer *buf, int cpu)
825{
826 u64 ts;
827
828 /* Early boot up does not have a buffer yet */
829 if (!buf->buffer)
830 return trace_clock_local();
831
832 ts = ring_buffer_time_stamp(buf->buffer);
833 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
834
835 return ts;
836}
837
838u64 ftrace_now(int cpu)
839{
840 return buffer_ftrace_now(&global_trace.array_buffer, cpu);
841}
842
843/**
844 * tracing_is_enabled - Show if global_trace has been enabled
845 *
846 * Shows if the global trace has been enabled or not. It uses the
847 * mirror flag "buffer_disabled" to be used in fast paths such as for
848 * the irqsoff tracer. But it may be inaccurate due to races. If you
849 * need to know the accurate state, use tracing_is_on() which is a little
850 * slower, but accurate.
851 */
852int tracing_is_enabled(void)
853{
854 /*
855 * For quick access (irqsoff uses this in fast path), just
856 * return the mirror variable of the state of the ring buffer.
857 * It's a little racy, but we don't really care.
858 */
859 smp_rmb();
860 return !global_trace.buffer_disabled;
861}
862
863/*
864 * trace_buf_size is the size in bytes that is allocated
865 * for a buffer. Note, the number of bytes is always rounded
866 * to page size.
867 *
868 * This number is purposely set to a low number of 16384.
869 * If the dump on oops happens, it will be much appreciated
870 * to not have to wait for all that output. Anyway this can be
871 * boot time and run time configurable.
872 */
873#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
874
875static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
876
877/* trace_types holds a link list of available tracers. */
878static struct tracer *trace_types __read_mostly;
879
880/*
881 * trace_types_lock is used to protect the trace_types list.
882 */
883DEFINE_MUTEX(trace_types_lock);
884
885/*
886 * serialize the access of the ring buffer
887 *
888 * ring buffer serializes readers, but it is low level protection.
889 * The validity of the events (which returns by ring_buffer_peek() ..etc)
890 * are not protected by ring buffer.
891 *
892 * The content of events may become garbage if we allow other process consumes
893 * these events concurrently:
894 * A) the page of the consumed events may become a normal page
895 * (not reader page) in ring buffer, and this page will be rewritten
896 * by events producer.
897 * B) The page of the consumed events may become a page for splice_read,
898 * and this page will be returned to system.
899 *
900 * These primitives allow multi process access to different cpu ring buffer
901 * concurrently.
902 *
903 * These primitives don't distinguish read-only and read-consume access.
904 * Multi read-only access are also serialized.
905 */
906
907#ifdef CONFIG_SMP
908static DECLARE_RWSEM(all_cpu_access_lock);
909static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
910
911static inline void trace_access_lock(int cpu)
912{
913 if (cpu == RING_BUFFER_ALL_CPUS) {
914 /* gain it for accessing the whole ring buffer. */
915 down_write(&all_cpu_access_lock);
916 } else {
917 /* gain it for accessing a cpu ring buffer. */
918
919 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
920 down_read(&all_cpu_access_lock);
921
922 /* Secondly block other access to this @cpu ring buffer. */
923 mutex_lock(&per_cpu(cpu_access_lock, cpu));
924 }
925}
926
927static inline void trace_access_unlock(int cpu)
928{
929 if (cpu == RING_BUFFER_ALL_CPUS) {
930 up_write(&all_cpu_access_lock);
931 } else {
932 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
933 up_read(&all_cpu_access_lock);
934 }
935}
936
937static inline void trace_access_lock_init(void)
938{
939 int cpu;
940
941 for_each_possible_cpu(cpu)
942 mutex_init(&per_cpu(cpu_access_lock, cpu));
943}
944
945#else
946
947static DEFINE_MUTEX(access_lock);
948
949static inline void trace_access_lock(int cpu)
950{
951 (void)cpu;
952 mutex_lock(&access_lock);
953}
954
955static inline void trace_access_unlock(int cpu)
956{
957 (void)cpu;
958 mutex_unlock(&access_lock);
959}
960
961static inline void trace_access_lock_init(void)
962{
963}
964
965#endif
966
967#ifdef CONFIG_STACKTRACE
968static void __ftrace_trace_stack(struct trace_buffer *buffer,
969 unsigned int trace_ctx,
970 int skip, struct pt_regs *regs);
971static inline void ftrace_trace_stack(struct trace_array *tr,
972 struct trace_buffer *buffer,
973 unsigned int trace_ctx,
974 int skip, struct pt_regs *regs);
975
976#else
977static inline void __ftrace_trace_stack(struct trace_buffer *buffer,
978 unsigned int trace_ctx,
979 int skip, struct pt_regs *regs)
980{
981}
982static inline void ftrace_trace_stack(struct trace_array *tr,
983 struct trace_buffer *buffer,
984 unsigned long trace_ctx,
985 int skip, struct pt_regs *regs)
986{
987}
988
989#endif
990
991static __always_inline void
992trace_event_setup(struct ring_buffer_event *event,
993 int type, unsigned int trace_ctx)
994{
995 struct trace_entry *ent = ring_buffer_event_data(event);
996
997 tracing_generic_entry_update(ent, type, trace_ctx);
998}
999
1000static __always_inline struct ring_buffer_event *
1001__trace_buffer_lock_reserve(struct trace_buffer *buffer,
1002 int type,
1003 unsigned long len,
1004 unsigned int trace_ctx)
1005{
1006 struct ring_buffer_event *event;
1007
1008 event = ring_buffer_lock_reserve(buffer, len);
1009 if (event != NULL)
1010 trace_event_setup(event, type, trace_ctx);
1011
1012 return event;
1013}
1014
1015void tracer_tracing_on(struct trace_array *tr)
1016{
1017 if (tr->array_buffer.buffer)
1018 ring_buffer_record_on(tr->array_buffer.buffer);
1019 /*
1020 * This flag is looked at when buffers haven't been allocated
1021 * yet, or by some tracers (like irqsoff), that just want to
1022 * know if the ring buffer has been disabled, but it can handle
1023 * races of where it gets disabled but we still do a record.
1024 * As the check is in the fast path of the tracers, it is more
1025 * important to be fast than accurate.
1026 */
1027 tr->buffer_disabled = 0;
1028 /* Make the flag seen by readers */
1029 smp_wmb();
1030}
1031
1032/**
1033 * tracing_on - enable tracing buffers
1034 *
1035 * This function enables tracing buffers that may have been
1036 * disabled with tracing_off.
1037 */
1038void tracing_on(void)
1039{
1040 tracer_tracing_on(&global_trace);
1041}
1042EXPORT_SYMBOL_GPL(tracing_on);
1043
1044
1045static __always_inline void
1046__buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *event)
1047{
1048 __this_cpu_write(trace_taskinfo_save, true);
1049
1050 /* If this is the temp buffer, we need to commit fully */
1051 if (this_cpu_read(trace_buffered_event) == event) {
1052 /* Length is in event->array[0] */
1053 ring_buffer_write(buffer, event->array[0], &event->array[1]);
1054 /* Release the temp buffer */
1055 this_cpu_dec(trace_buffered_event_cnt);
1056 /* ring_buffer_unlock_commit() enables preemption */
1057 preempt_enable_notrace();
1058 } else
1059 ring_buffer_unlock_commit(buffer);
1060}
1061
1062int __trace_array_puts(struct trace_array *tr, unsigned long ip,
1063 const char *str, int size)
1064{
1065 struct ring_buffer_event *event;
1066 struct trace_buffer *buffer;
1067 struct print_entry *entry;
1068 unsigned int trace_ctx;
1069 int alloc;
1070
1071 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
1072 return 0;
1073
1074 if (unlikely(tracing_selftest_running && tr == &global_trace))
1075 return 0;
1076
1077 if (unlikely(tracing_disabled))
1078 return 0;
1079
1080 alloc = sizeof(*entry) + size + 2; /* possible \n added */
1081
1082 trace_ctx = tracing_gen_ctx();
1083 buffer = tr->array_buffer.buffer;
1084 ring_buffer_nest_start(buffer);
1085 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
1086 trace_ctx);
1087 if (!event) {
1088 size = 0;
1089 goto out;
1090 }
1091
1092 entry = ring_buffer_event_data(event);
1093 entry->ip = ip;
1094
1095 memcpy(&entry->buf, str, size);
1096
1097 /* Add a newline if necessary */
1098 if (entry->buf[size - 1] != '\n') {
1099 entry->buf[size] = '\n';
1100 entry->buf[size + 1] = '\0';
1101 } else
1102 entry->buf[size] = '\0';
1103
1104 __buffer_unlock_commit(buffer, event);
1105 ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
1106 out:
1107 ring_buffer_nest_end(buffer);
1108 return size;
1109}
1110EXPORT_SYMBOL_GPL(__trace_array_puts);
1111
1112/**
1113 * __trace_puts - write a constant string into the trace buffer.
1114 * @ip: The address of the caller
1115 * @str: The constant string to write
1116 * @size: The size of the string.
1117 */
1118int __trace_puts(unsigned long ip, const char *str, int size)
1119{
1120 return __trace_array_puts(&global_trace, ip, str, size);
1121}
1122EXPORT_SYMBOL_GPL(__trace_puts);
1123
1124/**
1125 * __trace_bputs - write the pointer to a constant string into trace buffer
1126 * @ip: The address of the caller
1127 * @str: The constant string to write to the buffer to
1128 */
1129int __trace_bputs(unsigned long ip, const char *str)
1130{
1131 struct ring_buffer_event *event;
1132 struct trace_buffer *buffer;
1133 struct bputs_entry *entry;
1134 unsigned int trace_ctx;
1135 int size = sizeof(struct bputs_entry);
1136 int ret = 0;
1137
1138 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
1139 return 0;
1140
1141 if (unlikely(tracing_selftest_running || tracing_disabled))
1142 return 0;
1143
1144 trace_ctx = tracing_gen_ctx();
1145 buffer = global_trace.array_buffer.buffer;
1146
1147 ring_buffer_nest_start(buffer);
1148 event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
1149 trace_ctx);
1150 if (!event)
1151 goto out;
1152
1153 entry = ring_buffer_event_data(event);
1154 entry->ip = ip;
1155 entry->str = str;
1156
1157 __buffer_unlock_commit(buffer, event);
1158 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
1159
1160 ret = 1;
1161 out:
1162 ring_buffer_nest_end(buffer);
1163 return ret;
1164}
1165EXPORT_SYMBOL_GPL(__trace_bputs);
1166
1167#ifdef CONFIG_TRACER_SNAPSHOT
1168static void tracing_snapshot_instance_cond(struct trace_array *tr,
1169 void *cond_data)
1170{
1171 struct tracer *tracer = tr->current_trace;
1172 unsigned long flags;
1173
1174 if (in_nmi()) {
1175 trace_array_puts(tr, "*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
1176 trace_array_puts(tr, "*** snapshot is being ignored ***\n");
1177 return;
1178 }
1179
1180 if (!tr->allocated_snapshot) {
1181 trace_array_puts(tr, "*** SNAPSHOT NOT ALLOCATED ***\n");
1182 trace_array_puts(tr, "*** stopping trace here! ***\n");
1183 tracer_tracing_off(tr);
1184 return;
1185 }
1186
1187 /* Note, snapshot can not be used when the tracer uses it */
1188 if (tracer->use_max_tr) {
1189 trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n");
1190 trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
1191 return;
1192 }
1193
1194 local_irq_save(flags);
1195 update_max_tr(tr, current, smp_processor_id(), cond_data);
1196 local_irq_restore(flags);
1197}
1198
1199void tracing_snapshot_instance(struct trace_array *tr)
1200{
1201 tracing_snapshot_instance_cond(tr, NULL);
1202}
1203
1204/**
1205 * tracing_snapshot - take a snapshot of the current buffer.
1206 *
1207 * This causes a swap between the snapshot buffer and the current live
1208 * tracing buffer. You can use this to take snapshots of the live
1209 * trace when some condition is triggered, but continue to trace.
1210 *
1211 * Note, make sure to allocate the snapshot with either
1212 * a tracing_snapshot_alloc(), or by doing it manually
1213 * with: echo 1 > /sys/kernel/tracing/snapshot
1214 *
1215 * If the snapshot buffer is not allocated, it will stop tracing.
1216 * Basically making a permanent snapshot.
1217 */
1218void tracing_snapshot(void)
1219{
1220 struct trace_array *tr = &global_trace;
1221
1222 tracing_snapshot_instance(tr);
1223}
1224EXPORT_SYMBOL_GPL(tracing_snapshot);
1225
1226/**
1227 * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
1228 * @tr: The tracing instance to snapshot
1229 * @cond_data: The data to be tested conditionally, and possibly saved
1230 *
1231 * This is the same as tracing_snapshot() except that the snapshot is
1232 * conditional - the snapshot will only happen if the
1233 * cond_snapshot.update() implementation receiving the cond_data
1234 * returns true, which means that the trace array's cond_snapshot
1235 * update() operation used the cond_data to determine whether the
1236 * snapshot should be taken, and if it was, presumably saved it along
1237 * with the snapshot.
1238 */
1239void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1240{
1241 tracing_snapshot_instance_cond(tr, cond_data);
1242}
1243EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1244
1245/**
1246 * tracing_cond_snapshot_data - get the user data associated with a snapshot
1247 * @tr: The tracing instance
1248 *
1249 * When the user enables a conditional snapshot using
1250 * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
1251 * with the snapshot. This accessor is used to retrieve it.
1252 *
1253 * Should not be called from cond_snapshot.update(), since it takes
1254 * the tr->max_lock lock, which the code calling
1255 * cond_snapshot.update() has already done.
1256 *
1257 * Returns the cond_data associated with the trace array's snapshot.
1258 */
1259void *tracing_cond_snapshot_data(struct trace_array *tr)
1260{
1261 void *cond_data = NULL;
1262
1263 local_irq_disable();
1264 arch_spin_lock(&tr->max_lock);
1265
1266 if (tr->cond_snapshot)
1267 cond_data = tr->cond_snapshot->cond_data;
1268
1269 arch_spin_unlock(&tr->max_lock);
1270 local_irq_enable();
1271
1272 return cond_data;
1273}
1274EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1275
1276static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
1277 struct array_buffer *size_buf, int cpu_id);
1278static void set_buffer_entries(struct array_buffer *buf, unsigned long val);
1279
1280int tracing_alloc_snapshot_instance(struct trace_array *tr)
1281{
1282 int order;
1283 int ret;
1284
1285 if (!tr->allocated_snapshot) {
1286
1287 /* Make the snapshot buffer have the same order as main buffer */
1288 order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
1289 ret = ring_buffer_subbuf_order_set(tr->max_buffer.buffer, order);
1290 if (ret < 0)
1291 return ret;
1292
1293 /* allocate spare buffer */
1294 ret = resize_buffer_duplicate_size(&tr->max_buffer,
1295 &tr->array_buffer, RING_BUFFER_ALL_CPUS);
1296 if (ret < 0)
1297 return ret;
1298
1299 tr->allocated_snapshot = true;
1300 }
1301
1302 return 0;
1303}
1304
1305static void free_snapshot(struct trace_array *tr)
1306{
1307 /*
1308 * We don't free the ring buffer. instead, resize it because
1309 * The max_tr ring buffer has some state (e.g. ring->clock) and
1310 * we want preserve it.
1311 */
1312 ring_buffer_subbuf_order_set(tr->max_buffer.buffer, 0);
1313 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
1314 set_buffer_entries(&tr->max_buffer, 1);
1315 tracing_reset_online_cpus(&tr->max_buffer);
1316 tr->allocated_snapshot = false;
1317}
1318
1319static int tracing_arm_snapshot_locked(struct trace_array *tr)
1320{
1321 int ret;
1322
1323 lockdep_assert_held(&trace_types_lock);
1324
1325 spin_lock(&tr->snapshot_trigger_lock);
1326 if (tr->snapshot == UINT_MAX) {
1327 spin_unlock(&tr->snapshot_trigger_lock);
1328 return -EBUSY;
1329 }
1330
1331 tr->snapshot++;
1332 spin_unlock(&tr->snapshot_trigger_lock);
1333
1334 ret = tracing_alloc_snapshot_instance(tr);
1335 if (ret) {
1336 spin_lock(&tr->snapshot_trigger_lock);
1337 tr->snapshot--;
1338 spin_unlock(&tr->snapshot_trigger_lock);
1339 }
1340
1341 return ret;
1342}
1343
1344int tracing_arm_snapshot(struct trace_array *tr)
1345{
1346 int ret;
1347
1348 mutex_lock(&trace_types_lock);
1349 ret = tracing_arm_snapshot_locked(tr);
1350 mutex_unlock(&trace_types_lock);
1351
1352 return ret;
1353}
1354
1355void tracing_disarm_snapshot(struct trace_array *tr)
1356{
1357 spin_lock(&tr->snapshot_trigger_lock);
1358 if (!WARN_ON(!tr->snapshot))
1359 tr->snapshot--;
1360 spin_unlock(&tr->snapshot_trigger_lock);
1361}
1362
1363/**
1364 * tracing_alloc_snapshot - allocate snapshot buffer.
1365 *
1366 * This only allocates the snapshot buffer if it isn't already
1367 * allocated - it doesn't also take a snapshot.
1368 *
1369 * This is meant to be used in cases where the snapshot buffer needs
1370 * to be set up for events that can't sleep but need to be able to
1371 * trigger a snapshot.
1372 */
1373int tracing_alloc_snapshot(void)
1374{
1375 struct trace_array *tr = &global_trace;
1376 int ret;
1377
1378 ret = tracing_alloc_snapshot_instance(tr);
1379 WARN_ON(ret < 0);
1380
1381 return ret;
1382}
1383EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1384
1385/**
1386 * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
1387 *
1388 * This is similar to tracing_snapshot(), but it will allocate the
1389 * snapshot buffer if it isn't already allocated. Use this only
1390 * where it is safe to sleep, as the allocation may sleep.
1391 *
1392 * This causes a swap between the snapshot buffer and the current live
1393 * tracing buffer. You can use this to take snapshots of the live
1394 * trace when some condition is triggered, but continue to trace.
1395 */
1396void tracing_snapshot_alloc(void)
1397{
1398 int ret;
1399
1400 ret = tracing_alloc_snapshot();
1401 if (ret < 0)
1402 return;
1403
1404 tracing_snapshot();
1405}
1406EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1407
1408/**
1409 * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
1410 * @tr: The tracing instance
1411 * @cond_data: User data to associate with the snapshot
1412 * @update: Implementation of the cond_snapshot update function
1413 *
1414 * Check whether the conditional snapshot for the given instance has
1415 * already been enabled, or if the current tracer is already using a
1416 * snapshot; if so, return -EBUSY, else create a cond_snapshot and
1417 * save the cond_data and update function inside.
1418 *
1419 * Returns 0 if successful, error otherwise.
1420 */
1421int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
1422 cond_update_fn_t update)
1423{
1424 struct cond_snapshot *cond_snapshot;
1425 int ret = 0;
1426
1427 cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
1428 if (!cond_snapshot)
1429 return -ENOMEM;
1430
1431 cond_snapshot->cond_data = cond_data;
1432 cond_snapshot->update = update;
1433
1434 mutex_lock(&trace_types_lock);
1435
1436 if (tr->current_trace->use_max_tr) {
1437 ret = -EBUSY;
1438 goto fail_unlock;
1439 }
1440
1441 /*
1442 * The cond_snapshot can only change to NULL without the
1443 * trace_types_lock. We don't care if we race with it going
1444 * to NULL, but we want to make sure that it's not set to
1445 * something other than NULL when we get here, which we can
1446 * do safely with only holding the trace_types_lock and not
1447 * having to take the max_lock.
1448 */
1449 if (tr->cond_snapshot) {
1450 ret = -EBUSY;
1451 goto fail_unlock;
1452 }
1453
1454 ret = tracing_arm_snapshot_locked(tr);
1455 if (ret)
1456 goto fail_unlock;
1457
1458 local_irq_disable();
1459 arch_spin_lock(&tr->max_lock);
1460 tr->cond_snapshot = cond_snapshot;
1461 arch_spin_unlock(&tr->max_lock);
1462 local_irq_enable();
1463
1464 mutex_unlock(&trace_types_lock);
1465
1466 return ret;
1467
1468 fail_unlock:
1469 mutex_unlock(&trace_types_lock);
1470 kfree(cond_snapshot);
1471 return ret;
1472}
1473EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1474
1475/**
1476 * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
1477 * @tr: The tracing instance
1478 *
1479 * Check whether the conditional snapshot for the given instance is
1480 * enabled; if so, free the cond_snapshot associated with it,
1481 * otherwise return -EINVAL.
1482 *
1483 * Returns 0 if successful, error otherwise.
1484 */
1485int tracing_snapshot_cond_disable(struct trace_array *tr)
1486{
1487 int ret = 0;
1488
1489 local_irq_disable();
1490 arch_spin_lock(&tr->max_lock);
1491
1492 if (!tr->cond_snapshot)
1493 ret = -EINVAL;
1494 else {
1495 kfree(tr->cond_snapshot);
1496 tr->cond_snapshot = NULL;
1497 }
1498
1499 arch_spin_unlock(&tr->max_lock);
1500 local_irq_enable();
1501
1502 tracing_disarm_snapshot(tr);
1503
1504 return ret;
1505}
1506EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1507#else
1508void tracing_snapshot(void)
1509{
1510 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
1511}
1512EXPORT_SYMBOL_GPL(tracing_snapshot);
1513void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1514{
1515 WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
1516}
1517EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1518int tracing_alloc_snapshot(void)
1519{
1520 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
1521 return -ENODEV;
1522}
1523EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1524void tracing_snapshot_alloc(void)
1525{
1526 /* Give warning */
1527 tracing_snapshot();
1528}
1529EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1530void *tracing_cond_snapshot_data(struct trace_array *tr)
1531{
1532 return NULL;
1533}
1534EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1535int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
1536{
1537 return -ENODEV;
1538}
1539EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1540int tracing_snapshot_cond_disable(struct trace_array *tr)
1541{
1542 return false;
1543}
1544EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1545#define free_snapshot(tr) do { } while (0)
1546#define tracing_arm_snapshot_locked(tr) ({ -EBUSY; })
1547#endif /* CONFIG_TRACER_SNAPSHOT */
1548
1549void tracer_tracing_off(struct trace_array *tr)
1550{
1551 if (tr->array_buffer.buffer)
1552 ring_buffer_record_off(tr->array_buffer.buffer);
1553 /*
1554 * This flag is looked at when buffers haven't been allocated
1555 * yet, or by some tracers (like irqsoff), that just want to
1556 * know if the ring buffer has been disabled, but it can handle
1557 * races of where it gets disabled but we still do a record.
1558 * As the check is in the fast path of the tracers, it is more
1559 * important to be fast than accurate.
1560 */
1561 tr->buffer_disabled = 1;
1562 /* Make the flag seen by readers */
1563 smp_wmb();
1564}
1565
1566/**
1567 * tracing_off - turn off tracing buffers
1568 *
1569 * This function stops the tracing buffers from recording data.
1570 * It does not disable any overhead the tracers themselves may
1571 * be causing. This function simply causes all recording to
1572 * the ring buffers to fail.
1573 */
1574void tracing_off(void)
1575{
1576 tracer_tracing_off(&global_trace);
1577}
1578EXPORT_SYMBOL_GPL(tracing_off);
1579
1580void disable_trace_on_warning(void)
1581{
1582 if (__disable_trace_on_warning) {
1583 trace_array_printk_buf(global_trace.array_buffer.buffer, _THIS_IP_,
1584 "Disabling tracing due to warning\n");
1585 tracing_off();
1586 }
1587}
1588
1589/**
1590 * tracer_tracing_is_on - show real state of ring buffer enabled
1591 * @tr : the trace array to know if ring buffer is enabled
1592 *
1593 * Shows real state of the ring buffer if it is enabled or not.
1594 */
1595bool tracer_tracing_is_on(struct trace_array *tr)
1596{
1597 if (tr->array_buffer.buffer)
1598 return ring_buffer_record_is_set_on(tr->array_buffer.buffer);
1599 return !tr->buffer_disabled;
1600}
1601
1602/**
1603 * tracing_is_on - show state of ring buffers enabled
1604 */
1605int tracing_is_on(void)
1606{
1607 return tracer_tracing_is_on(&global_trace);
1608}
1609EXPORT_SYMBOL_GPL(tracing_is_on);
1610
1611static int __init set_buf_size(char *str)
1612{
1613 unsigned long buf_size;
1614
1615 if (!str)
1616 return 0;
1617 buf_size = memparse(str, &str);
1618 /*
1619 * nr_entries can not be zero and the startup
1620 * tests require some buffer space. Therefore
1621 * ensure we have at least 4096 bytes of buffer.
1622 */
1623 trace_buf_size = max(4096UL, buf_size);
1624 return 1;
1625}
1626__setup("trace_buf_size=", set_buf_size);
1627
1628static int __init set_tracing_thresh(char *str)
1629{
1630 unsigned long threshold;
1631 int ret;
1632
1633 if (!str)
1634 return 0;
1635 ret = kstrtoul(str, 0, &threshold);
1636 if (ret < 0)
1637 return 0;
1638 tracing_thresh = threshold * 1000;
1639 return 1;
1640}
1641__setup("tracing_thresh=", set_tracing_thresh);
1642
1643unsigned long nsecs_to_usecs(unsigned long nsecs)
1644{
1645 return nsecs / 1000;
1646}
1647
1648/*
1649 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
1650 * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
1651 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
1652 * of strings in the order that the evals (enum) were defined.
1653 */
1654#undef C
1655#define C(a, b) b
1656
1657/* These must match the bit positions in trace_iterator_flags */
1658static const char *trace_options[] = {
1659 TRACE_FLAGS
1660 NULL
1661};
1662
1663static struct {
1664 u64 (*func)(void);
1665 const char *name;
1666 int in_ns; /* is this clock in nanoseconds? */
1667} trace_clocks[] = {
1668 { trace_clock_local, "local", 1 },
1669 { trace_clock_global, "global", 1 },
1670 { trace_clock_counter, "counter", 0 },
1671 { trace_clock_jiffies, "uptime", 0 },
1672 { trace_clock, "perf", 1 },
1673 { ktime_get_mono_fast_ns, "mono", 1 },
1674 { ktime_get_raw_fast_ns, "mono_raw", 1 },
1675 { ktime_get_boot_fast_ns, "boot", 1 },
1676 { ktime_get_tai_fast_ns, "tai", 1 },
1677 ARCH_TRACE_CLOCKS
1678};
1679
1680bool trace_clock_in_ns(struct trace_array *tr)
1681{
1682 if (trace_clocks[tr->clock_id].in_ns)
1683 return true;
1684
1685 return false;
1686}
1687
1688/*
1689 * trace_parser_get_init - gets the buffer for trace parser
1690 */
1691int trace_parser_get_init(struct trace_parser *parser, int size)
1692{
1693 memset(parser, 0, sizeof(*parser));
1694
1695 parser->buffer = kmalloc(size, GFP_KERNEL);
1696 if (!parser->buffer)
1697 return 1;
1698
1699 parser->size = size;
1700 return 0;
1701}
1702
1703/*
1704 * trace_parser_put - frees the buffer for trace parser
1705 */
1706void trace_parser_put(struct trace_parser *parser)
1707{
1708 kfree(parser->buffer);
1709 parser->buffer = NULL;
1710}
1711
1712/*
1713 * trace_get_user - reads the user input string separated by space
1714 * (matched by isspace(ch))
1715 *
1716 * For each string found the 'struct trace_parser' is updated,
1717 * and the function returns.
1718 *
1719 * Returns number of bytes read.
1720 *
1721 * See kernel/trace/trace.h for 'struct trace_parser' details.
1722 */
1723int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1724 size_t cnt, loff_t *ppos)
1725{
1726 char ch;
1727 size_t read = 0;
1728 ssize_t ret;
1729
1730 if (!*ppos)
1731 trace_parser_clear(parser);
1732
1733 ret = get_user(ch, ubuf++);
1734 if (ret)
1735 goto out;
1736
1737 read++;
1738 cnt--;
1739
1740 /*
1741 * The parser is not finished with the last write,
1742 * continue reading the user input without skipping spaces.
1743 */
1744 if (!parser->cont) {
1745 /* skip white space */
1746 while (cnt && isspace(ch)) {
1747 ret = get_user(ch, ubuf++);
1748 if (ret)
1749 goto out;
1750 read++;
1751 cnt--;
1752 }
1753
1754 parser->idx = 0;
1755
1756 /* only spaces were written */
1757 if (isspace(ch) || !ch) {
1758 *ppos += read;
1759 ret = read;
1760 goto out;
1761 }
1762 }
1763
1764 /* read the non-space input */
1765 while (cnt && !isspace(ch) && ch) {
1766 if (parser->idx < parser->size - 1)
1767 parser->buffer[parser->idx++] = ch;
1768 else {
1769 ret = -EINVAL;
1770 goto out;
1771 }
1772 ret = get_user(ch, ubuf++);
1773 if (ret)
1774 goto out;
1775 read++;
1776 cnt--;
1777 }
1778
1779 /* We either got finished input or we have to wait for another call. */
1780 if (isspace(ch) || !ch) {
1781 parser->buffer[parser->idx] = 0;
1782 parser->cont = false;
1783 } else if (parser->idx < parser->size - 1) {
1784 parser->cont = true;
1785 parser->buffer[parser->idx++] = ch;
1786 /* Make sure the parsed string always terminates with '\0'. */
1787 parser->buffer[parser->idx] = 0;
1788 } else {
1789 ret = -EINVAL;
1790 goto out;
1791 }
1792
1793 *ppos += read;
1794 ret = read;
1795
1796out:
1797 return ret;
1798}
1799
1800/* TODO add a seq_buf_to_buffer() */
1801static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1802{
1803 int len;
1804
1805 if (trace_seq_used(s) <= s->readpos)
1806 return -EBUSY;
1807
1808 len = trace_seq_used(s) - s->readpos;
1809 if (cnt > len)
1810 cnt = len;
1811 memcpy(buf, s->buffer + s->readpos, cnt);
1812
1813 s->readpos += cnt;
1814 return cnt;
1815}
1816
1817unsigned long __read_mostly tracing_thresh;
1818
1819#ifdef CONFIG_TRACER_MAX_TRACE
1820static const struct file_operations tracing_max_lat_fops;
1821
1822#ifdef LATENCY_FS_NOTIFY
1823
1824static struct workqueue_struct *fsnotify_wq;
1825
1826static void latency_fsnotify_workfn(struct work_struct *work)
1827{
1828 struct trace_array *tr = container_of(work, struct trace_array,
1829 fsnotify_work);
1830 fsnotify_inode(tr->d_max_latency->d_inode, FS_MODIFY);
1831}
1832
1833static void latency_fsnotify_workfn_irq(struct irq_work *iwork)
1834{
1835 struct trace_array *tr = container_of(iwork, struct trace_array,
1836 fsnotify_irqwork);
1837 queue_work(fsnotify_wq, &tr->fsnotify_work);
1838}
1839
1840static void trace_create_maxlat_file(struct trace_array *tr,
1841 struct dentry *d_tracer)
1842{
1843 INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
1844 init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
1845 tr->d_max_latency = trace_create_file("tracing_max_latency",
1846 TRACE_MODE_WRITE,
1847 d_tracer, tr,
1848 &tracing_max_lat_fops);
1849}
1850
1851__init static int latency_fsnotify_init(void)
1852{
1853 fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
1854 WQ_UNBOUND | WQ_HIGHPRI, 0);
1855 if (!fsnotify_wq) {
1856 pr_err("Unable to allocate tr_max_lat_wq\n");
1857 return -ENOMEM;
1858 }
1859 return 0;
1860}
1861
1862late_initcall_sync(latency_fsnotify_init);
1863
1864void latency_fsnotify(struct trace_array *tr)
1865{
1866 if (!fsnotify_wq)
1867 return;
1868 /*
1869 * We cannot call queue_work(&tr->fsnotify_work) from here because it's
1870 * possible that we are called from __schedule() or do_idle(), which
1871 * could cause a deadlock.
1872 */
1873 irq_work_queue(&tr->fsnotify_irqwork);
1874}
1875
1876#else /* !LATENCY_FS_NOTIFY */
1877
1878#define trace_create_maxlat_file(tr, d_tracer) \
1879 trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \
1880 d_tracer, tr, &tracing_max_lat_fops)
1881
1882#endif
1883
1884/*
1885 * Copy the new maximum trace into the separate maximum-trace
1886 * structure. (this way the maximum trace is permanently saved,
1887 * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
1888 */
1889static void
1890__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1891{
1892 struct array_buffer *trace_buf = &tr->array_buffer;
1893 struct array_buffer *max_buf = &tr->max_buffer;
1894 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1895 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1896
1897 max_buf->cpu = cpu;
1898 max_buf->time_start = data->preempt_timestamp;
1899
1900 max_data->saved_latency = tr->max_latency;
1901 max_data->critical_start = data->critical_start;
1902 max_data->critical_end = data->critical_end;
1903
1904 strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1905 max_data->pid = tsk->pid;
1906 /*
1907 * If tsk == current, then use current_uid(), as that does not use
1908 * RCU. The irq tracer can be called out of RCU scope.
1909 */
1910 if (tsk == current)
1911 max_data->uid = current_uid();
1912 else
1913 max_data->uid = task_uid(tsk);
1914
1915 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1916 max_data->policy = tsk->policy;
1917 max_data->rt_priority = tsk->rt_priority;
1918
1919 /* record this tasks comm */
1920 tracing_record_cmdline(tsk);
1921 latency_fsnotify(tr);
1922}
1923
1924/**
1925 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1926 * @tr: tracer
1927 * @tsk: the task with the latency
1928 * @cpu: The cpu that initiated the trace.
1929 * @cond_data: User data associated with a conditional snapshot
1930 *
1931 * Flip the buffers between the @tr and the max_tr and record information
1932 * about which task was the cause of this latency.
1933 */
1934void
1935update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
1936 void *cond_data)
1937{
1938 if (tr->stop_count)
1939 return;
1940
1941 WARN_ON_ONCE(!irqs_disabled());
1942
1943 if (!tr->allocated_snapshot) {
1944 /* Only the nop tracer should hit this when disabling */
1945 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1946 return;
1947 }
1948
1949 arch_spin_lock(&tr->max_lock);
1950
1951 /* Inherit the recordable setting from array_buffer */
1952 if (ring_buffer_record_is_set_on(tr->array_buffer.buffer))
1953 ring_buffer_record_on(tr->max_buffer.buffer);
1954 else
1955 ring_buffer_record_off(tr->max_buffer.buffer);
1956
1957#ifdef CONFIG_TRACER_SNAPSHOT
1958 if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data)) {
1959 arch_spin_unlock(&tr->max_lock);
1960 return;
1961 }
1962#endif
1963 swap(tr->array_buffer.buffer, tr->max_buffer.buffer);
1964
1965 __update_max_tr(tr, tsk, cpu);
1966
1967 arch_spin_unlock(&tr->max_lock);
1968
1969 /* Any waiters on the old snapshot buffer need to wake up */
1970 ring_buffer_wake_waiters(tr->array_buffer.buffer, RING_BUFFER_ALL_CPUS);
1971}
1972
1973/**
1974 * update_max_tr_single - only copy one trace over, and reset the rest
1975 * @tr: tracer
1976 * @tsk: task with the latency
1977 * @cpu: the cpu of the buffer to copy.
1978 *
1979 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1980 */
1981void
1982update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1983{
1984 int ret;
1985
1986 if (tr->stop_count)
1987 return;
1988
1989 WARN_ON_ONCE(!irqs_disabled());
1990 if (!tr->allocated_snapshot) {
1991 /* Only the nop tracer should hit this when disabling */
1992 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1993 return;
1994 }
1995
1996 arch_spin_lock(&tr->max_lock);
1997
1998 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu);
1999
2000 if (ret == -EBUSY) {
2001 /*
2002 * We failed to swap the buffer due to a commit taking
2003 * place on this CPU. We fail to record, but we reset
2004 * the max trace buffer (no one writes directly to it)
2005 * and flag that it failed.
2006 * Another reason is resize is in progress.
2007 */
2008 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
2009 "Failed to swap buffers due to commit or resize in progress\n");
2010 }
2011
2012 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
2013
2014 __update_max_tr(tr, tsk, cpu);
2015 arch_spin_unlock(&tr->max_lock);
2016}
2017
2018#endif /* CONFIG_TRACER_MAX_TRACE */
2019
2020struct pipe_wait {
2021 struct trace_iterator *iter;
2022 int wait_index;
2023};
2024
2025static bool wait_pipe_cond(void *data)
2026{
2027 struct pipe_wait *pwait = data;
2028 struct trace_iterator *iter = pwait->iter;
2029
2030 if (atomic_read_acquire(&iter->wait_index) != pwait->wait_index)
2031 return true;
2032
2033 return iter->closed;
2034}
2035
2036static int wait_on_pipe(struct trace_iterator *iter, int full)
2037{
2038 struct pipe_wait pwait;
2039 int ret;
2040
2041 /* Iterators are static, they should be filled or empty */
2042 if (trace_buffer_iter(iter, iter->cpu_file))
2043 return 0;
2044
2045 pwait.wait_index = atomic_read_acquire(&iter->wait_index);
2046 pwait.iter = iter;
2047
2048 ret = ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file, full,
2049 wait_pipe_cond, &pwait);
2050
2051#ifdef CONFIG_TRACER_MAX_TRACE
2052 /*
2053 * Make sure this is still the snapshot buffer, as if a snapshot were
2054 * to happen, this would now be the main buffer.
2055 */
2056 if (iter->snapshot)
2057 iter->array_buffer = &iter->tr->max_buffer;
2058#endif
2059 return ret;
2060}
2061
2062#ifdef CONFIG_FTRACE_STARTUP_TEST
2063static bool selftests_can_run;
2064
2065struct trace_selftests {
2066 struct list_head list;
2067 struct tracer *type;
2068};
2069
2070static LIST_HEAD(postponed_selftests);
2071
2072static int save_selftest(struct tracer *type)
2073{
2074 struct trace_selftests *selftest;
2075
2076 selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
2077 if (!selftest)
2078 return -ENOMEM;
2079
2080 selftest->type = type;
2081 list_add(&selftest->list, &postponed_selftests);
2082 return 0;
2083}
2084
2085static int run_tracer_selftest(struct tracer *type)
2086{
2087 struct trace_array *tr = &global_trace;
2088 struct tracer *saved_tracer = tr->current_trace;
2089 int ret;
2090
2091 if (!type->selftest || tracing_selftest_disabled)
2092 return 0;
2093
2094 /*
2095 * If a tracer registers early in boot up (before scheduling is
2096 * initialized and such), then do not run its selftests yet.
2097 * Instead, run it a little later in the boot process.
2098 */
2099 if (!selftests_can_run)
2100 return save_selftest(type);
2101
2102 if (!tracing_is_on()) {
2103 pr_warn("Selftest for tracer %s skipped due to tracing disabled\n",
2104 type->name);
2105 return 0;
2106 }
2107
2108 /*
2109 * Run a selftest on this tracer.
2110 * Here we reset the trace buffer, and set the current
2111 * tracer to be this tracer. The tracer can then run some
2112 * internal tracing to verify that everything is in order.
2113 * If we fail, we do not register this tracer.
2114 */
2115 tracing_reset_online_cpus(&tr->array_buffer);
2116
2117 tr->current_trace = type;
2118
2119#ifdef CONFIG_TRACER_MAX_TRACE
2120 if (type->use_max_tr) {
2121 /* If we expanded the buffers, make sure the max is expanded too */
2122 if (tr->ring_buffer_expanded)
2123 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
2124 RING_BUFFER_ALL_CPUS);
2125 tr->allocated_snapshot = true;
2126 }
2127#endif
2128
2129 /* the test is responsible for initializing and enabling */
2130 pr_info("Testing tracer %s: ", type->name);
2131 ret = type->selftest(type, tr);
2132 /* the test is responsible for resetting too */
2133 tr->current_trace = saved_tracer;
2134 if (ret) {
2135 printk(KERN_CONT "FAILED!\n");
2136 /* Add the warning after printing 'FAILED' */
2137 WARN_ON(1);
2138 return -1;
2139 }
2140 /* Only reset on passing, to avoid touching corrupted buffers */
2141 tracing_reset_online_cpus(&tr->array_buffer);
2142
2143#ifdef CONFIG_TRACER_MAX_TRACE
2144 if (type->use_max_tr) {
2145 tr->allocated_snapshot = false;
2146
2147 /* Shrink the max buffer again */
2148 if (tr->ring_buffer_expanded)
2149 ring_buffer_resize(tr->max_buffer.buffer, 1,
2150 RING_BUFFER_ALL_CPUS);
2151 }
2152#endif
2153
2154 printk(KERN_CONT "PASSED\n");
2155 return 0;
2156}
2157
2158static int do_run_tracer_selftest(struct tracer *type)
2159{
2160 int ret;
2161
2162 /*
2163 * Tests can take a long time, especially if they are run one after the
2164 * other, as does happen during bootup when all the tracers are
2165 * registered. This could cause the soft lockup watchdog to trigger.
2166 */
2167 cond_resched();
2168
2169 tracing_selftest_running = true;
2170 ret = run_tracer_selftest(type);
2171 tracing_selftest_running = false;
2172
2173 return ret;
2174}
2175
2176static __init int init_trace_selftests(void)
2177{
2178 struct trace_selftests *p, *n;
2179 struct tracer *t, **last;
2180 int ret;
2181
2182 selftests_can_run = true;
2183
2184 mutex_lock(&trace_types_lock);
2185
2186 if (list_empty(&postponed_selftests))
2187 goto out;
2188
2189 pr_info("Running postponed tracer tests:\n");
2190
2191 tracing_selftest_running = true;
2192 list_for_each_entry_safe(p, n, &postponed_selftests, list) {
2193 /* This loop can take minutes when sanitizers are enabled, so
2194 * lets make sure we allow RCU processing.
2195 */
2196 cond_resched();
2197 ret = run_tracer_selftest(p->type);
2198 /* If the test fails, then warn and remove from available_tracers */
2199 if (ret < 0) {
2200 WARN(1, "tracer: %s failed selftest, disabling\n",
2201 p->type->name);
2202 last = &trace_types;
2203 for (t = trace_types; t; t = t->next) {
2204 if (t == p->type) {
2205 *last = t->next;
2206 break;
2207 }
2208 last = &t->next;
2209 }
2210 }
2211 list_del(&p->list);
2212 kfree(p);
2213 }
2214 tracing_selftest_running = false;
2215
2216 out:
2217 mutex_unlock(&trace_types_lock);
2218
2219 return 0;
2220}
2221core_initcall(init_trace_selftests);
2222#else
2223static inline int run_tracer_selftest(struct tracer *type)
2224{
2225 return 0;
2226}
2227static inline int do_run_tracer_selftest(struct tracer *type)
2228{
2229 return 0;
2230}
2231#endif /* CONFIG_FTRACE_STARTUP_TEST */
2232
2233static void add_tracer_options(struct trace_array *tr, struct tracer *t);
2234
2235static void __init apply_trace_boot_options(void);
2236
2237/**
2238 * register_tracer - register a tracer with the ftrace system.
2239 * @type: the plugin for the tracer
2240 *
2241 * Register a new plugin tracer.
2242 */
2243int __init register_tracer(struct tracer *type)
2244{
2245 struct tracer *t;
2246 int ret = 0;
2247
2248 if (!type->name) {
2249 pr_info("Tracer must have a name\n");
2250 return -1;
2251 }
2252
2253 if (strlen(type->name) >= MAX_TRACER_SIZE) {
2254 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
2255 return -1;
2256 }
2257
2258 if (security_locked_down(LOCKDOWN_TRACEFS)) {
2259 pr_warn("Can not register tracer %s due to lockdown\n",
2260 type->name);
2261 return -EPERM;
2262 }
2263
2264 mutex_lock(&trace_types_lock);
2265
2266 for (t = trace_types; t; t = t->next) {
2267 if (strcmp(type->name, t->name) == 0) {
2268 /* already found */
2269 pr_info("Tracer %s already registered\n",
2270 type->name);
2271 ret = -1;
2272 goto out;
2273 }
2274 }
2275
2276 if (!type->set_flag)
2277 type->set_flag = &dummy_set_flag;
2278 if (!type->flags) {
2279 /*allocate a dummy tracer_flags*/
2280 type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
2281 if (!type->flags) {
2282 ret = -ENOMEM;
2283 goto out;
2284 }
2285 type->flags->val = 0;
2286 type->flags->opts = dummy_tracer_opt;
2287 } else
2288 if (!type->flags->opts)
2289 type->flags->opts = dummy_tracer_opt;
2290
2291 /* store the tracer for __set_tracer_option */
2292 type->flags->trace = type;
2293
2294 ret = do_run_tracer_selftest(type);
2295 if (ret < 0)
2296 goto out;
2297
2298 type->next = trace_types;
2299 trace_types = type;
2300 add_tracer_options(&global_trace, type);
2301
2302 out:
2303 mutex_unlock(&trace_types_lock);
2304
2305 if (ret || !default_bootup_tracer)
2306 goto out_unlock;
2307
2308 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
2309 goto out_unlock;
2310
2311 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
2312 /* Do we want this tracer to start on bootup? */
2313 tracing_set_tracer(&global_trace, type->name);
2314 default_bootup_tracer = NULL;
2315
2316 apply_trace_boot_options();
2317
2318 /* disable other selftests, since this will break it. */
2319 disable_tracing_selftest("running a tracer");
2320
2321 out_unlock:
2322 return ret;
2323}
2324
2325static void tracing_reset_cpu(struct array_buffer *buf, int cpu)
2326{
2327 struct trace_buffer *buffer = buf->buffer;
2328
2329 if (!buffer)
2330 return;
2331
2332 ring_buffer_record_disable(buffer);
2333
2334 /* Make sure all commits have finished */
2335 synchronize_rcu();
2336 ring_buffer_reset_cpu(buffer, cpu);
2337
2338 ring_buffer_record_enable(buffer);
2339}
2340
2341void tracing_reset_online_cpus(struct array_buffer *buf)
2342{
2343 struct trace_buffer *buffer = buf->buffer;
2344
2345 if (!buffer)
2346 return;
2347
2348 ring_buffer_record_disable(buffer);
2349
2350 /* Make sure all commits have finished */
2351 synchronize_rcu();
2352
2353 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
2354
2355 ring_buffer_reset_online_cpus(buffer);
2356
2357 ring_buffer_record_enable(buffer);
2358}
2359
2360/* Must have trace_types_lock held */
2361void tracing_reset_all_online_cpus_unlocked(void)
2362{
2363 struct trace_array *tr;
2364
2365 lockdep_assert_held(&trace_types_lock);
2366
2367 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2368 if (!tr->clear_trace)
2369 continue;
2370 tr->clear_trace = false;
2371 tracing_reset_online_cpus(&tr->array_buffer);
2372#ifdef CONFIG_TRACER_MAX_TRACE
2373 tracing_reset_online_cpus(&tr->max_buffer);
2374#endif
2375 }
2376}
2377
2378void tracing_reset_all_online_cpus(void)
2379{
2380 mutex_lock(&trace_types_lock);
2381 tracing_reset_all_online_cpus_unlocked();
2382 mutex_unlock(&trace_types_lock);
2383}
2384
2385int is_tracing_stopped(void)
2386{
2387 return global_trace.stop_count;
2388}
2389
2390static void tracing_start_tr(struct trace_array *tr)
2391{
2392 struct trace_buffer *buffer;
2393 unsigned long flags;
2394
2395 if (tracing_disabled)
2396 return;
2397
2398 raw_spin_lock_irqsave(&tr->start_lock, flags);
2399 if (--tr->stop_count) {
2400 if (WARN_ON_ONCE(tr->stop_count < 0)) {
2401 /* Someone screwed up their debugging */
2402 tr->stop_count = 0;
2403 }
2404 goto out;
2405 }
2406
2407 /* Prevent the buffers from switching */
2408 arch_spin_lock(&tr->max_lock);
2409
2410 buffer = tr->array_buffer.buffer;
2411 if (buffer)
2412 ring_buffer_record_enable(buffer);
2413
2414#ifdef CONFIG_TRACER_MAX_TRACE
2415 buffer = tr->max_buffer.buffer;
2416 if (buffer)
2417 ring_buffer_record_enable(buffer);
2418#endif
2419
2420 arch_spin_unlock(&tr->max_lock);
2421
2422 out:
2423 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2424}
2425
2426/**
2427 * tracing_start - quick start of the tracer
2428 *
2429 * If tracing is enabled but was stopped by tracing_stop,
2430 * this will start the tracer back up.
2431 */
2432void tracing_start(void)
2433
2434{
2435 return tracing_start_tr(&global_trace);
2436}
2437
2438static void tracing_stop_tr(struct trace_array *tr)
2439{
2440 struct trace_buffer *buffer;
2441 unsigned long flags;
2442
2443 raw_spin_lock_irqsave(&tr->start_lock, flags);
2444 if (tr->stop_count++)
2445 goto out;
2446
2447 /* Prevent the buffers from switching */
2448 arch_spin_lock(&tr->max_lock);
2449
2450 buffer = tr->array_buffer.buffer;
2451 if (buffer)
2452 ring_buffer_record_disable(buffer);
2453
2454#ifdef CONFIG_TRACER_MAX_TRACE
2455 buffer = tr->max_buffer.buffer;
2456 if (buffer)
2457 ring_buffer_record_disable(buffer);
2458#endif
2459
2460 arch_spin_unlock(&tr->max_lock);
2461
2462 out:
2463 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2464}
2465
2466/**
2467 * tracing_stop - quick stop of the tracer
2468 *
2469 * Light weight way to stop tracing. Use in conjunction with
2470 * tracing_start.
2471 */
2472void tracing_stop(void)
2473{
2474 return tracing_stop_tr(&global_trace);
2475}
2476
2477/*
2478 * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
2479 * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
2480 * simplifies those functions and keeps them in sync.
2481 */
2482enum print_line_t trace_handle_return(struct trace_seq *s)
2483{
2484 return trace_seq_has_overflowed(s) ?
2485 TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
2486}
2487EXPORT_SYMBOL_GPL(trace_handle_return);
2488
2489static unsigned short migration_disable_value(void)
2490{
2491#if defined(CONFIG_SMP)
2492 return current->migration_disabled;
2493#else
2494 return 0;
2495#endif
2496}
2497
2498unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
2499{
2500 unsigned int trace_flags = irqs_status;
2501 unsigned int pc;
2502
2503 pc = preempt_count();
2504
2505 if (pc & NMI_MASK)
2506 trace_flags |= TRACE_FLAG_NMI;
2507 if (pc & HARDIRQ_MASK)
2508 trace_flags |= TRACE_FLAG_HARDIRQ;
2509 if (in_serving_softirq())
2510 trace_flags |= TRACE_FLAG_SOFTIRQ;
2511 if (softirq_count() >> (SOFTIRQ_SHIFT + 1))
2512 trace_flags |= TRACE_FLAG_BH_OFF;
2513
2514 if (tif_need_resched())
2515 trace_flags |= TRACE_FLAG_NEED_RESCHED;
2516 if (test_preempt_need_resched())
2517 trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
2518 return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) |
2519 (min_t(unsigned int, migration_disable_value(), 0xf)) << 4;
2520}
2521
2522struct ring_buffer_event *
2523trace_buffer_lock_reserve(struct trace_buffer *buffer,
2524 int type,
2525 unsigned long len,
2526 unsigned int trace_ctx)
2527{
2528 return __trace_buffer_lock_reserve(buffer, type, len, trace_ctx);
2529}
2530
2531DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
2532DEFINE_PER_CPU(int, trace_buffered_event_cnt);
2533static int trace_buffered_event_ref;
2534
2535/**
2536 * trace_buffered_event_enable - enable buffering events
2537 *
2538 * When events are being filtered, it is quicker to use a temporary
2539 * buffer to write the event data into if there's a likely chance
2540 * that it will not be committed. The discard of the ring buffer
2541 * is not as fast as committing, and is much slower than copying
2542 * a commit.
2543 *
2544 * When an event is to be filtered, allocate per cpu buffers to
2545 * write the event data into, and if the event is filtered and discarded
2546 * it is simply dropped, otherwise, the entire data is to be committed
2547 * in one shot.
2548 */
2549void trace_buffered_event_enable(void)
2550{
2551 struct ring_buffer_event *event;
2552 struct page *page;
2553 int cpu;
2554
2555 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2556
2557 if (trace_buffered_event_ref++)
2558 return;
2559
2560 for_each_tracing_cpu(cpu) {
2561 page = alloc_pages_node(cpu_to_node(cpu),
2562 GFP_KERNEL | __GFP_NORETRY, 0);
2563 /* This is just an optimization and can handle failures */
2564 if (!page) {
2565 pr_err("Failed to allocate event buffer\n");
2566 break;
2567 }
2568
2569 event = page_address(page);
2570 memset(event, 0, sizeof(*event));
2571
2572 per_cpu(trace_buffered_event, cpu) = event;
2573
2574 preempt_disable();
2575 if (cpu == smp_processor_id() &&
2576 __this_cpu_read(trace_buffered_event) !=
2577 per_cpu(trace_buffered_event, cpu))
2578 WARN_ON_ONCE(1);
2579 preempt_enable();
2580 }
2581}
2582
2583static void enable_trace_buffered_event(void *data)
2584{
2585 /* Probably not needed, but do it anyway */
2586 smp_rmb();
2587 this_cpu_dec(trace_buffered_event_cnt);
2588}
2589
2590static void disable_trace_buffered_event(void *data)
2591{
2592 this_cpu_inc(trace_buffered_event_cnt);
2593}
2594
2595/**
2596 * trace_buffered_event_disable - disable buffering events
2597 *
2598 * When a filter is removed, it is faster to not use the buffered
2599 * events, and to commit directly into the ring buffer. Free up
2600 * the temp buffers when there are no more users. This requires
2601 * special synchronization with current events.
2602 */
2603void trace_buffered_event_disable(void)
2604{
2605 int cpu;
2606
2607 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2608
2609 if (WARN_ON_ONCE(!trace_buffered_event_ref))
2610 return;
2611
2612 if (--trace_buffered_event_ref)
2613 return;
2614
2615 /* For each CPU, set the buffer as used. */
2616 on_each_cpu_mask(tracing_buffer_mask, disable_trace_buffered_event,
2617 NULL, true);
2618
2619 /* Wait for all current users to finish */
2620 synchronize_rcu();
2621
2622 for_each_tracing_cpu(cpu) {
2623 free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
2624 per_cpu(trace_buffered_event, cpu) = NULL;
2625 }
2626
2627 /*
2628 * Wait for all CPUs that potentially started checking if they can use
2629 * their event buffer only after the previous synchronize_rcu() call and
2630 * they still read a valid pointer from trace_buffered_event. It must be
2631 * ensured they don't see cleared trace_buffered_event_cnt else they
2632 * could wrongly decide to use the pointed-to buffer which is now freed.
2633 */
2634 synchronize_rcu();
2635
2636 /* For each CPU, relinquish the buffer */
2637 on_each_cpu_mask(tracing_buffer_mask, enable_trace_buffered_event, NULL,
2638 true);
2639}
2640
2641static struct trace_buffer *temp_buffer;
2642
2643struct ring_buffer_event *
2644trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
2645 struct trace_event_file *trace_file,
2646 int type, unsigned long len,
2647 unsigned int trace_ctx)
2648{
2649 struct ring_buffer_event *entry;
2650 struct trace_array *tr = trace_file->tr;
2651 int val;
2652
2653 *current_rb = tr->array_buffer.buffer;
2654
2655 if (!tr->no_filter_buffering_ref &&
2656 (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED))) {
2657 preempt_disable_notrace();
2658 /*
2659 * Filtering is on, so try to use the per cpu buffer first.
2660 * This buffer will simulate a ring_buffer_event,
2661 * where the type_len is zero and the array[0] will
2662 * hold the full length.
2663 * (see include/linux/ring-buffer.h for details on
2664 * how the ring_buffer_event is structured).
2665 *
2666 * Using a temp buffer during filtering and copying it
2667 * on a matched filter is quicker than writing directly
2668 * into the ring buffer and then discarding it when
2669 * it doesn't match. That is because the discard
2670 * requires several atomic operations to get right.
2671 * Copying on match and doing nothing on a failed match
2672 * is still quicker than no copy on match, but having
2673 * to discard out of the ring buffer on a failed match.
2674 */
2675 if ((entry = __this_cpu_read(trace_buffered_event))) {
2676 int max_len = PAGE_SIZE - struct_size(entry, array, 1);
2677
2678 val = this_cpu_inc_return(trace_buffered_event_cnt);
2679
2680 /*
2681 * Preemption is disabled, but interrupts and NMIs
2682 * can still come in now. If that happens after
2683 * the above increment, then it will have to go
2684 * back to the old method of allocating the event
2685 * on the ring buffer, and if the filter fails, it
2686 * will have to call ring_buffer_discard_commit()
2687 * to remove it.
2688 *
2689 * Need to also check the unlikely case that the
2690 * length is bigger than the temp buffer size.
2691 * If that happens, then the reserve is pretty much
2692 * guaranteed to fail, as the ring buffer currently
2693 * only allows events less than a page. But that may
2694 * change in the future, so let the ring buffer reserve
2695 * handle the failure in that case.
2696 */
2697 if (val == 1 && likely(len <= max_len)) {
2698 trace_event_setup(entry, type, trace_ctx);
2699 entry->array[0] = len;
2700 /* Return with preemption disabled */
2701 return entry;
2702 }
2703 this_cpu_dec(trace_buffered_event_cnt);
2704 }
2705 /* __trace_buffer_lock_reserve() disables preemption */
2706 preempt_enable_notrace();
2707 }
2708
2709 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2710 trace_ctx);
2711 /*
2712 * If tracing is off, but we have triggers enabled
2713 * we still need to look at the event data. Use the temp_buffer
2714 * to store the trace event for the trigger to use. It's recursive
2715 * safe and will not be recorded anywhere.
2716 */
2717 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
2718 *current_rb = temp_buffer;
2719 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2720 trace_ctx);
2721 }
2722 return entry;
2723}
2724EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
2725
2726static DEFINE_RAW_SPINLOCK(tracepoint_iter_lock);
2727static DEFINE_MUTEX(tracepoint_printk_mutex);
2728
2729static void output_printk(struct trace_event_buffer *fbuffer)
2730{
2731 struct trace_event_call *event_call;
2732 struct trace_event_file *file;
2733 struct trace_event *event;
2734 unsigned long flags;
2735 struct trace_iterator *iter = tracepoint_print_iter;
2736
2737 /* We should never get here if iter is NULL */
2738 if (WARN_ON_ONCE(!iter))
2739 return;
2740
2741 event_call = fbuffer->trace_file->event_call;
2742 if (!event_call || !event_call->event.funcs ||
2743 !event_call->event.funcs->trace)
2744 return;
2745
2746 file = fbuffer->trace_file;
2747 if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) ||
2748 (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
2749 !filter_match_preds(file->filter, fbuffer->entry)))
2750 return;
2751
2752 event = &fbuffer->trace_file->event_call->event;
2753
2754 raw_spin_lock_irqsave(&tracepoint_iter_lock, flags);
2755 trace_seq_init(&iter->seq);
2756 iter->ent = fbuffer->entry;
2757 event_call->event.funcs->trace(iter, 0, event);
2758 trace_seq_putc(&iter->seq, 0);
2759 printk("%s", iter->seq.buffer);
2760
2761 raw_spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
2762}
2763
2764int tracepoint_printk_sysctl(struct ctl_table *table, int write,
2765 void *buffer, size_t *lenp,
2766 loff_t *ppos)
2767{
2768 int save_tracepoint_printk;
2769 int ret;
2770
2771 mutex_lock(&tracepoint_printk_mutex);
2772 save_tracepoint_printk = tracepoint_printk;
2773
2774 ret = proc_dointvec(table, write, buffer, lenp, ppos);
2775
2776 /*
2777 * This will force exiting early, as tracepoint_printk
2778 * is always zero when tracepoint_printk_iter is not allocated
2779 */
2780 if (!tracepoint_print_iter)
2781 tracepoint_printk = 0;
2782
2783 if (save_tracepoint_printk == tracepoint_printk)
2784 goto out;
2785
2786 if (tracepoint_printk)
2787 static_key_enable(&tracepoint_printk_key.key);
2788 else
2789 static_key_disable(&tracepoint_printk_key.key);
2790
2791 out:
2792 mutex_unlock(&tracepoint_printk_mutex);
2793
2794 return ret;
2795}
2796
2797void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
2798{
2799 enum event_trigger_type tt = ETT_NONE;
2800 struct trace_event_file *file = fbuffer->trace_file;
2801
2802 if (__event_trigger_test_discard(file, fbuffer->buffer, fbuffer->event,
2803 fbuffer->entry, &tt))
2804 goto discard;
2805
2806 if (static_key_false(&tracepoint_printk_key.key))
2807 output_printk(fbuffer);
2808
2809 if (static_branch_unlikely(&trace_event_exports_enabled))
2810 ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT);
2811
2812 trace_buffer_unlock_commit_regs(file->tr, fbuffer->buffer,
2813 fbuffer->event, fbuffer->trace_ctx, fbuffer->regs);
2814
2815discard:
2816 if (tt)
2817 event_triggers_post_call(file, tt);
2818
2819}
2820EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
2821
2822/*
2823 * Skip 3:
2824 *
2825 * trace_buffer_unlock_commit_regs()
2826 * trace_event_buffer_commit()
2827 * trace_event_raw_event_xxx()
2828 */
2829# define STACK_SKIP 3
2830
2831void trace_buffer_unlock_commit_regs(struct trace_array *tr,
2832 struct trace_buffer *buffer,
2833 struct ring_buffer_event *event,
2834 unsigned int trace_ctx,
2835 struct pt_regs *regs)
2836{
2837 __buffer_unlock_commit(buffer, event);
2838
2839 /*
2840 * If regs is not set, then skip the necessary functions.
2841 * Note, we can still get here via blktrace, wakeup tracer
2842 * and mmiotrace, but that's ok if they lose a function or
2843 * two. They are not that meaningful.
2844 */
2845 ftrace_trace_stack(tr, buffer, trace_ctx, regs ? 0 : STACK_SKIP, regs);
2846 ftrace_trace_userstack(tr, buffer, trace_ctx);
2847}
2848
2849/*
2850 * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
2851 */
2852void
2853trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
2854 struct ring_buffer_event *event)
2855{
2856 __buffer_unlock_commit(buffer, event);
2857}
2858
2859void
2860trace_function(struct trace_array *tr, unsigned long ip, unsigned long
2861 parent_ip, unsigned int trace_ctx)
2862{
2863 struct trace_event_call *call = &event_function;
2864 struct trace_buffer *buffer = tr->array_buffer.buffer;
2865 struct ring_buffer_event *event;
2866 struct ftrace_entry *entry;
2867
2868 event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
2869 trace_ctx);
2870 if (!event)
2871 return;
2872 entry = ring_buffer_event_data(event);
2873 entry->ip = ip;
2874 entry->parent_ip = parent_ip;
2875
2876 if (!call_filter_check_discard(call, entry, buffer, event)) {
2877 if (static_branch_unlikely(&trace_function_exports_enabled))
2878 ftrace_exports(event, TRACE_EXPORT_FUNCTION);
2879 __buffer_unlock_commit(buffer, event);
2880 }
2881}
2882
2883#ifdef CONFIG_STACKTRACE
2884
2885/* Allow 4 levels of nesting: normal, softirq, irq, NMI */
2886#define FTRACE_KSTACK_NESTING 4
2887
2888#define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING)
2889
2890struct ftrace_stack {
2891 unsigned long calls[FTRACE_KSTACK_ENTRIES];
2892};
2893
2894
2895struct ftrace_stacks {
2896 struct ftrace_stack stacks[FTRACE_KSTACK_NESTING];
2897};
2898
2899static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
2900static DEFINE_PER_CPU(int, ftrace_stack_reserve);
2901
2902static void __ftrace_trace_stack(struct trace_buffer *buffer,
2903 unsigned int trace_ctx,
2904 int skip, struct pt_regs *regs)
2905{
2906 struct trace_event_call *call = &event_kernel_stack;
2907 struct ring_buffer_event *event;
2908 unsigned int size, nr_entries;
2909 struct ftrace_stack *fstack;
2910 struct stack_entry *entry;
2911 int stackidx;
2912
2913 /*
2914 * Add one, for this function and the call to save_stack_trace()
2915 * If regs is set, then these functions will not be in the way.
2916 */
2917#ifndef CONFIG_UNWINDER_ORC
2918 if (!regs)
2919 skip++;
2920#endif
2921
2922 preempt_disable_notrace();
2923
2924 stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
2925
2926 /* This should never happen. If it does, yell once and skip */
2927 if (WARN_ON_ONCE(stackidx >= FTRACE_KSTACK_NESTING))
2928 goto out;
2929
2930 /*
2931 * The above __this_cpu_inc_return() is 'atomic' cpu local. An
2932 * interrupt will either see the value pre increment or post
2933 * increment. If the interrupt happens pre increment it will have
2934 * restored the counter when it returns. We just need a barrier to
2935 * keep gcc from moving things around.
2936 */
2937 barrier();
2938
2939 fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx;
2940 size = ARRAY_SIZE(fstack->calls);
2941
2942 if (regs) {
2943 nr_entries = stack_trace_save_regs(regs, fstack->calls,
2944 size, skip);
2945 } else {
2946 nr_entries = stack_trace_save(fstack->calls, size, skip);
2947 }
2948
2949 event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
2950 struct_size(entry, caller, nr_entries),
2951 trace_ctx);
2952 if (!event)
2953 goto out;
2954 entry = ring_buffer_event_data(event);
2955
2956 entry->size = nr_entries;
2957 memcpy(&entry->caller, fstack->calls,
2958 flex_array_size(entry, caller, nr_entries));
2959
2960 if (!call_filter_check_discard(call, entry, buffer, event))
2961 __buffer_unlock_commit(buffer, event);
2962
2963 out:
2964 /* Again, don't let gcc optimize things here */
2965 barrier();
2966 __this_cpu_dec(ftrace_stack_reserve);
2967 preempt_enable_notrace();
2968
2969}
2970
2971static inline void ftrace_trace_stack(struct trace_array *tr,
2972 struct trace_buffer *buffer,
2973 unsigned int trace_ctx,
2974 int skip, struct pt_regs *regs)
2975{
2976 if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
2977 return;
2978
2979 __ftrace_trace_stack(buffer, trace_ctx, skip, regs);
2980}
2981
2982void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
2983 int skip)
2984{
2985 struct trace_buffer *buffer = tr->array_buffer.buffer;
2986
2987 if (rcu_is_watching()) {
2988 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
2989 return;
2990 }
2991
2992 if (WARN_ON_ONCE(IS_ENABLED(CONFIG_GENERIC_ENTRY)))
2993 return;
2994
2995 /*
2996 * When an NMI triggers, RCU is enabled via ct_nmi_enter(),
2997 * but if the above rcu_is_watching() failed, then the NMI
2998 * triggered someplace critical, and ct_irq_enter() should
2999 * not be called from NMI.
3000 */
3001 if (unlikely(in_nmi()))
3002 return;
3003
3004 ct_irq_enter_irqson();
3005 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
3006 ct_irq_exit_irqson();
3007}
3008
3009/**
3010 * trace_dump_stack - record a stack back trace in the trace buffer
3011 * @skip: Number of functions to skip (helper handlers)
3012 */
3013void trace_dump_stack(int skip)
3014{
3015 if (tracing_disabled || tracing_selftest_running)
3016 return;
3017
3018#ifndef CONFIG_UNWINDER_ORC
3019 /* Skip 1 to skip this function. */
3020 skip++;
3021#endif
3022 __ftrace_trace_stack(global_trace.array_buffer.buffer,
3023 tracing_gen_ctx(), skip, NULL);
3024}
3025EXPORT_SYMBOL_GPL(trace_dump_stack);
3026
3027#ifdef CONFIG_USER_STACKTRACE_SUPPORT
3028static DEFINE_PER_CPU(int, user_stack_count);
3029
3030static void
3031ftrace_trace_userstack(struct trace_array *tr,
3032 struct trace_buffer *buffer, unsigned int trace_ctx)
3033{
3034 struct trace_event_call *call = &event_user_stack;
3035 struct ring_buffer_event *event;
3036 struct userstack_entry *entry;
3037
3038 if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE))
3039 return;
3040
3041 /*
3042 * NMIs can not handle page faults, even with fix ups.
3043 * The save user stack can (and often does) fault.
3044 */
3045 if (unlikely(in_nmi()))
3046 return;
3047
3048 /*
3049 * prevent recursion, since the user stack tracing may
3050 * trigger other kernel events.
3051 */
3052 preempt_disable();
3053 if (__this_cpu_read(user_stack_count))
3054 goto out;
3055
3056 __this_cpu_inc(user_stack_count);
3057
3058 event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
3059 sizeof(*entry), trace_ctx);
3060 if (!event)
3061 goto out_drop_count;
3062 entry = ring_buffer_event_data(event);
3063
3064 entry->tgid = current->tgid;
3065 memset(&entry->caller, 0, sizeof(entry->caller));
3066
3067 stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES);
3068 if (!call_filter_check_discard(call, entry, buffer, event))
3069 __buffer_unlock_commit(buffer, event);
3070
3071 out_drop_count:
3072 __this_cpu_dec(user_stack_count);
3073 out:
3074 preempt_enable();
3075}
3076#else /* CONFIG_USER_STACKTRACE_SUPPORT */
3077static void ftrace_trace_userstack(struct trace_array *tr,
3078 struct trace_buffer *buffer,
3079 unsigned int trace_ctx)
3080{
3081}
3082#endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
3083
3084#endif /* CONFIG_STACKTRACE */
3085
3086static inline void
3087func_repeats_set_delta_ts(struct func_repeats_entry *entry,
3088 unsigned long long delta)
3089{
3090 entry->bottom_delta_ts = delta & U32_MAX;
3091 entry->top_delta_ts = (delta >> 32);
3092}
3093
3094void trace_last_func_repeats(struct trace_array *tr,
3095 struct trace_func_repeats *last_info,
3096 unsigned int trace_ctx)
3097{
3098 struct trace_buffer *buffer = tr->array_buffer.buffer;
3099 struct func_repeats_entry *entry;
3100 struct ring_buffer_event *event;
3101 u64 delta;
3102
3103 event = __trace_buffer_lock_reserve(buffer, TRACE_FUNC_REPEATS,
3104 sizeof(*entry), trace_ctx);
3105 if (!event)
3106 return;
3107
3108 delta = ring_buffer_event_time_stamp(buffer, event) -
3109 last_info->ts_last_call;
3110
3111 entry = ring_buffer_event_data(event);
3112 entry->ip = last_info->ip;
3113 entry->parent_ip = last_info->parent_ip;
3114 entry->count = last_info->count;
3115 func_repeats_set_delta_ts(entry, delta);
3116
3117 __buffer_unlock_commit(buffer, event);
3118}
3119
3120/* created for use with alloc_percpu */
3121struct trace_buffer_struct {
3122 int nesting;
3123 char buffer[4][TRACE_BUF_SIZE];
3124};
3125
3126static struct trace_buffer_struct __percpu *trace_percpu_buffer;
3127
3128/*
3129 * This allows for lockless recording. If we're nested too deeply, then
3130 * this returns NULL.
3131 */
3132static char *get_trace_buf(void)
3133{
3134 struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
3135
3136 if (!trace_percpu_buffer || buffer->nesting >= 4)
3137 return NULL;
3138
3139 buffer->nesting++;
3140
3141 /* Interrupts must see nesting incremented before we use the buffer */
3142 barrier();
3143 return &buffer->buffer[buffer->nesting - 1][0];
3144}
3145
3146static void put_trace_buf(void)
3147{
3148 /* Don't let the decrement of nesting leak before this */
3149 barrier();
3150 this_cpu_dec(trace_percpu_buffer->nesting);
3151}
3152
3153static int alloc_percpu_trace_buffer(void)
3154{
3155 struct trace_buffer_struct __percpu *buffers;
3156
3157 if (trace_percpu_buffer)
3158 return 0;
3159
3160 buffers = alloc_percpu(struct trace_buffer_struct);
3161 if (MEM_FAIL(!buffers, "Could not allocate percpu trace_printk buffer"))
3162 return -ENOMEM;
3163
3164 trace_percpu_buffer = buffers;
3165 return 0;
3166}
3167
3168static int buffers_allocated;
3169
3170void trace_printk_init_buffers(void)
3171{
3172 if (buffers_allocated)
3173 return;
3174
3175 if (alloc_percpu_trace_buffer())
3176 return;
3177
3178 /* trace_printk() is for debug use only. Don't use it in production. */
3179
3180 pr_warn("\n");
3181 pr_warn("**********************************************************\n");
3182 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3183 pr_warn("** **\n");
3184 pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
3185 pr_warn("** **\n");
3186 pr_warn("** This means that this is a DEBUG kernel and it is **\n");
3187 pr_warn("** unsafe for production use. **\n");
3188 pr_warn("** **\n");
3189 pr_warn("** If you see this message and you are not debugging **\n");
3190 pr_warn("** the kernel, report this immediately to your vendor! **\n");
3191 pr_warn("** **\n");
3192 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3193 pr_warn("**********************************************************\n");
3194
3195 /* Expand the buffers to set size */
3196 tracing_update_buffers(&global_trace);
3197
3198 buffers_allocated = 1;
3199
3200 /*
3201 * trace_printk_init_buffers() can be called by modules.
3202 * If that happens, then we need to start cmdline recording
3203 * directly here. If the global_trace.buffer is already
3204 * allocated here, then this was called by module code.
3205 */
3206 if (global_trace.array_buffer.buffer)
3207 tracing_start_cmdline_record();
3208}
3209EXPORT_SYMBOL_GPL(trace_printk_init_buffers);
3210
3211void trace_printk_start_comm(void)
3212{
3213 /* Start tracing comms if trace printk is set */
3214 if (!buffers_allocated)
3215 return;
3216 tracing_start_cmdline_record();
3217}
3218
3219static void trace_printk_start_stop_comm(int enabled)
3220{
3221 if (!buffers_allocated)
3222 return;
3223
3224 if (enabled)
3225 tracing_start_cmdline_record();
3226 else
3227 tracing_stop_cmdline_record();
3228}
3229
3230/**
3231 * trace_vbprintk - write binary msg to tracing buffer
3232 * @ip: The address of the caller
3233 * @fmt: The string format to write to the buffer
3234 * @args: Arguments for @fmt
3235 */
3236int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
3237{
3238 struct trace_event_call *call = &event_bprint;
3239 struct ring_buffer_event *event;
3240 struct trace_buffer *buffer;
3241 struct trace_array *tr = &global_trace;
3242 struct bprint_entry *entry;
3243 unsigned int trace_ctx;
3244 char *tbuffer;
3245 int len = 0, size;
3246
3247 if (unlikely(tracing_selftest_running || tracing_disabled))
3248 return 0;
3249
3250 /* Don't pollute graph traces with trace_vprintk internals */
3251 pause_graph_tracing();
3252
3253 trace_ctx = tracing_gen_ctx();
3254 preempt_disable_notrace();
3255
3256 tbuffer = get_trace_buf();
3257 if (!tbuffer) {
3258 len = 0;
3259 goto out_nobuffer;
3260 }
3261
3262 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
3263
3264 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
3265 goto out_put;
3266
3267 size = sizeof(*entry) + sizeof(u32) * len;
3268 buffer = tr->array_buffer.buffer;
3269 ring_buffer_nest_start(buffer);
3270 event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
3271 trace_ctx);
3272 if (!event)
3273 goto out;
3274 entry = ring_buffer_event_data(event);
3275 entry->ip = ip;
3276 entry->fmt = fmt;
3277
3278 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
3279 if (!call_filter_check_discard(call, entry, buffer, event)) {
3280 __buffer_unlock_commit(buffer, event);
3281 ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL);
3282 }
3283
3284out:
3285 ring_buffer_nest_end(buffer);
3286out_put:
3287 put_trace_buf();
3288
3289out_nobuffer:
3290 preempt_enable_notrace();
3291 unpause_graph_tracing();
3292
3293 return len;
3294}
3295EXPORT_SYMBOL_GPL(trace_vbprintk);
3296
3297__printf(3, 0)
3298static int
3299__trace_array_vprintk(struct trace_buffer *buffer,
3300 unsigned long ip, const char *fmt, va_list args)
3301{
3302 struct trace_event_call *call = &event_print;
3303 struct ring_buffer_event *event;
3304 int len = 0, size;
3305 struct print_entry *entry;
3306 unsigned int trace_ctx;
3307 char *tbuffer;
3308
3309 if (tracing_disabled)
3310 return 0;
3311
3312 /* Don't pollute graph traces with trace_vprintk internals */
3313 pause_graph_tracing();
3314
3315 trace_ctx = tracing_gen_ctx();
3316 preempt_disable_notrace();
3317
3318
3319 tbuffer = get_trace_buf();
3320 if (!tbuffer) {
3321 len = 0;
3322 goto out_nobuffer;
3323 }
3324
3325 len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
3326
3327 size = sizeof(*entry) + len + 1;
3328 ring_buffer_nest_start(buffer);
3329 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3330 trace_ctx);
3331 if (!event)
3332 goto out;
3333 entry = ring_buffer_event_data(event);
3334 entry->ip = ip;
3335
3336 memcpy(&entry->buf, tbuffer, len + 1);
3337 if (!call_filter_check_discard(call, entry, buffer, event)) {
3338 __buffer_unlock_commit(buffer, event);
3339 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 6, NULL);
3340 }
3341
3342out:
3343 ring_buffer_nest_end(buffer);
3344 put_trace_buf();
3345
3346out_nobuffer:
3347 preempt_enable_notrace();
3348 unpause_graph_tracing();
3349
3350 return len;
3351}
3352
3353__printf(3, 0)
3354int trace_array_vprintk(struct trace_array *tr,
3355 unsigned long ip, const char *fmt, va_list args)
3356{
3357 if (tracing_selftest_running && tr == &global_trace)
3358 return 0;
3359
3360 return __trace_array_vprintk(tr->array_buffer.buffer, ip, fmt, args);
3361}
3362
3363/**
3364 * trace_array_printk - Print a message to a specific instance
3365 * @tr: The instance trace_array descriptor
3366 * @ip: The instruction pointer that this is called from.
3367 * @fmt: The format to print (printf format)
3368 *
3369 * If a subsystem sets up its own instance, they have the right to
3370 * printk strings into their tracing instance buffer using this
3371 * function. Note, this function will not write into the top level
3372 * buffer (use trace_printk() for that), as writing into the top level
3373 * buffer should only have events that can be individually disabled.
3374 * trace_printk() is only used for debugging a kernel, and should not
3375 * be ever incorporated in normal use.
3376 *
3377 * trace_array_printk() can be used, as it will not add noise to the
3378 * top level tracing buffer.
3379 *
3380 * Note, trace_array_init_printk() must be called on @tr before this
3381 * can be used.
3382 */
3383__printf(3, 0)
3384int trace_array_printk(struct trace_array *tr,
3385 unsigned long ip, const char *fmt, ...)
3386{
3387 int ret;
3388 va_list ap;
3389
3390 if (!tr)
3391 return -ENOENT;
3392
3393 /* This is only allowed for created instances */
3394 if (tr == &global_trace)
3395 return 0;
3396
3397 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
3398 return 0;
3399
3400 va_start(ap, fmt);
3401 ret = trace_array_vprintk(tr, ip, fmt, ap);
3402 va_end(ap);
3403 return ret;
3404}
3405EXPORT_SYMBOL_GPL(trace_array_printk);
3406
3407/**
3408 * trace_array_init_printk - Initialize buffers for trace_array_printk()
3409 * @tr: The trace array to initialize the buffers for
3410 *
3411 * As trace_array_printk() only writes into instances, they are OK to
3412 * have in the kernel (unlike trace_printk()). This needs to be called
3413 * before trace_array_printk() can be used on a trace_array.
3414 */
3415int trace_array_init_printk(struct trace_array *tr)
3416{
3417 if (!tr)
3418 return -ENOENT;
3419
3420 /* This is only allowed for created instances */
3421 if (tr == &global_trace)
3422 return -EINVAL;
3423
3424 return alloc_percpu_trace_buffer();
3425}
3426EXPORT_SYMBOL_GPL(trace_array_init_printk);
3427
3428__printf(3, 4)
3429int trace_array_printk_buf(struct trace_buffer *buffer,
3430 unsigned long ip, const char *fmt, ...)
3431{
3432 int ret;
3433 va_list ap;
3434
3435 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
3436 return 0;
3437
3438 va_start(ap, fmt);
3439 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
3440 va_end(ap);
3441 return ret;
3442}
3443
3444__printf(2, 0)
3445int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3446{
3447 return trace_array_vprintk(&global_trace, ip, fmt, args);
3448}
3449EXPORT_SYMBOL_GPL(trace_vprintk);
3450
3451static void trace_iterator_increment(struct trace_iterator *iter)
3452{
3453 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
3454
3455 iter->idx++;
3456 if (buf_iter)
3457 ring_buffer_iter_advance(buf_iter);
3458}
3459
3460static struct trace_entry *
3461peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
3462 unsigned long *lost_events)
3463{
3464 struct ring_buffer_event *event;
3465 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
3466
3467 if (buf_iter) {
3468 event = ring_buffer_iter_peek(buf_iter, ts);
3469 if (lost_events)
3470 *lost_events = ring_buffer_iter_dropped(buf_iter) ?
3471 (unsigned long)-1 : 0;
3472 } else {
3473 event = ring_buffer_peek(iter->array_buffer->buffer, cpu, ts,
3474 lost_events);
3475 }
3476
3477 if (event) {
3478 iter->ent_size = ring_buffer_event_length(event);
3479 return ring_buffer_event_data(event);
3480 }
3481 iter->ent_size = 0;
3482 return NULL;
3483}
3484
3485static struct trace_entry *
3486__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
3487 unsigned long *missing_events, u64 *ent_ts)
3488{
3489 struct trace_buffer *buffer = iter->array_buffer->buffer;
3490 struct trace_entry *ent, *next = NULL;
3491 unsigned long lost_events = 0, next_lost = 0;
3492 int cpu_file = iter->cpu_file;
3493 u64 next_ts = 0, ts;
3494 int next_cpu = -1;
3495 int next_size = 0;
3496 int cpu;
3497
3498 /*
3499 * If we are in a per_cpu trace file, don't bother by iterating over
3500 * all cpu and peek directly.
3501 */
3502 if (cpu_file > RING_BUFFER_ALL_CPUS) {
3503 if (ring_buffer_empty_cpu(buffer, cpu_file))
3504 return NULL;
3505 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
3506 if (ent_cpu)
3507 *ent_cpu = cpu_file;
3508
3509 return ent;
3510 }
3511
3512 for_each_tracing_cpu(cpu) {
3513
3514 if (ring_buffer_empty_cpu(buffer, cpu))
3515 continue;
3516
3517 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
3518
3519 /*
3520 * Pick the entry with the smallest timestamp:
3521 */
3522 if (ent && (!next || ts < next_ts)) {
3523 next = ent;
3524 next_cpu = cpu;
3525 next_ts = ts;
3526 next_lost = lost_events;
3527 next_size = iter->ent_size;
3528 }
3529 }
3530
3531 iter->ent_size = next_size;
3532
3533 if (ent_cpu)
3534 *ent_cpu = next_cpu;
3535
3536 if (ent_ts)
3537 *ent_ts = next_ts;
3538
3539 if (missing_events)
3540 *missing_events = next_lost;
3541
3542 return next;
3543}
3544
3545#define STATIC_FMT_BUF_SIZE 128
3546static char static_fmt_buf[STATIC_FMT_BUF_SIZE];
3547
3548char *trace_iter_expand_format(struct trace_iterator *iter)
3549{
3550 char *tmp;
3551
3552 /*
3553 * iter->tr is NULL when used with tp_printk, which makes
3554 * this get called where it is not safe to call krealloc().
3555 */
3556 if (!iter->tr || iter->fmt == static_fmt_buf)
3557 return NULL;
3558
3559 tmp = krealloc(iter->fmt, iter->fmt_size + STATIC_FMT_BUF_SIZE,
3560 GFP_KERNEL);
3561 if (tmp) {
3562 iter->fmt_size += STATIC_FMT_BUF_SIZE;
3563 iter->fmt = tmp;
3564 }
3565
3566 return tmp;
3567}
3568
3569/* Returns true if the string is safe to dereference from an event */
3570static bool trace_safe_str(struct trace_iterator *iter, const char *str,
3571 bool star, int len)
3572{
3573 unsigned long addr = (unsigned long)str;
3574 struct trace_event *trace_event;
3575 struct trace_event_call *event;
3576
3577 /* Ignore strings with no length */
3578 if (star && !len)
3579 return true;
3580
3581 /* OK if part of the event data */
3582 if ((addr >= (unsigned long)iter->ent) &&
3583 (addr < (unsigned long)iter->ent + iter->ent_size))
3584 return true;
3585
3586 /* OK if part of the temp seq buffer */
3587 if ((addr >= (unsigned long)iter->tmp_seq.buffer) &&
3588 (addr < (unsigned long)iter->tmp_seq.buffer + TRACE_SEQ_BUFFER_SIZE))
3589 return true;
3590
3591 /* Core rodata can not be freed */
3592 if (is_kernel_rodata(addr))
3593 return true;
3594
3595 if (trace_is_tracepoint_string(str))
3596 return true;
3597
3598 /*
3599 * Now this could be a module event, referencing core module
3600 * data, which is OK.
3601 */
3602 if (!iter->ent)
3603 return false;
3604
3605 trace_event = ftrace_find_event(iter->ent->type);
3606 if (!trace_event)
3607 return false;
3608
3609 event = container_of(trace_event, struct trace_event_call, event);
3610 if ((event->flags & TRACE_EVENT_FL_DYNAMIC) || !event->module)
3611 return false;
3612
3613 /* Would rather have rodata, but this will suffice */
3614 if (within_module_core(addr, event->module))
3615 return true;
3616
3617 return false;
3618}
3619
3620static DEFINE_STATIC_KEY_FALSE(trace_no_verify);
3621
3622static int test_can_verify_check(const char *fmt, ...)
3623{
3624 char buf[16];
3625 va_list ap;
3626 int ret;
3627
3628 /*
3629 * The verifier is dependent on vsnprintf() modifies the va_list
3630 * passed to it, where it is sent as a reference. Some architectures
3631 * (like x86_32) passes it by value, which means that vsnprintf()
3632 * does not modify the va_list passed to it, and the verifier
3633 * would then need to be able to understand all the values that
3634 * vsnprintf can use. If it is passed by value, then the verifier
3635 * is disabled.
3636 */
3637 va_start(ap, fmt);
3638 vsnprintf(buf, 16, "%d", ap);
3639 ret = va_arg(ap, int);
3640 va_end(ap);
3641
3642 return ret;
3643}
3644
3645static void test_can_verify(void)
3646{
3647 if (!test_can_verify_check("%d %d", 0, 1)) {
3648 pr_info("trace event string verifier disabled\n");
3649 static_branch_inc(&trace_no_verify);
3650 }
3651}
3652
3653/**
3654 * trace_check_vprintf - Check dereferenced strings while writing to the seq buffer
3655 * @iter: The iterator that holds the seq buffer and the event being printed
3656 * @fmt: The format used to print the event
3657 * @ap: The va_list holding the data to print from @fmt.
3658 *
3659 * This writes the data into the @iter->seq buffer using the data from
3660 * @fmt and @ap. If the format has a %s, then the source of the string
3661 * is examined to make sure it is safe to print, otherwise it will
3662 * warn and print "[UNSAFE MEMORY]" in place of the dereferenced string
3663 * pointer.
3664 */
3665void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
3666 va_list ap)
3667{
3668 const char *p = fmt;
3669 const char *str;
3670 int i, j;
3671
3672 if (WARN_ON_ONCE(!fmt))
3673 return;
3674
3675 if (static_branch_unlikely(&trace_no_verify))
3676 goto print;
3677
3678 /* Don't bother checking when doing a ftrace_dump() */
3679 if (iter->fmt == static_fmt_buf)
3680 goto print;
3681
3682 while (*p) {
3683 bool star = false;
3684 int len = 0;
3685
3686 j = 0;
3687
3688 /* We only care about %s and variants */
3689 for (i = 0; p[i]; i++) {
3690 if (i + 1 >= iter->fmt_size) {
3691 /*
3692 * If we can't expand the copy buffer,
3693 * just print it.
3694 */
3695 if (!trace_iter_expand_format(iter))
3696 goto print;
3697 }
3698
3699 if (p[i] == '\\' && p[i+1]) {
3700 i++;
3701 continue;
3702 }
3703 if (p[i] == '%') {
3704 /* Need to test cases like %08.*s */
3705 for (j = 1; p[i+j]; j++) {
3706 if (isdigit(p[i+j]) ||
3707 p[i+j] == '.')
3708 continue;
3709 if (p[i+j] == '*') {
3710 star = true;
3711 continue;
3712 }
3713 break;
3714 }
3715 if (p[i+j] == 's')
3716 break;
3717 star = false;
3718 }
3719 j = 0;
3720 }
3721 /* If no %s found then just print normally */
3722 if (!p[i])
3723 break;
3724
3725 /* Copy up to the %s, and print that */
3726 strncpy(iter->fmt, p, i);
3727 iter->fmt[i] = '\0';
3728 trace_seq_vprintf(&iter->seq, iter->fmt, ap);
3729
3730 /*
3731 * If iter->seq is full, the above call no longer guarantees
3732 * that ap is in sync with fmt processing, and further calls
3733 * to va_arg() can return wrong positional arguments.
3734 *
3735 * Ensure that ap is no longer used in this case.
3736 */
3737 if (iter->seq.full) {
3738 p = "";
3739 break;
3740 }
3741
3742 if (star)
3743 len = va_arg(ap, int);
3744
3745 /* The ap now points to the string data of the %s */
3746 str = va_arg(ap, const char *);
3747
3748 /*
3749 * If you hit this warning, it is likely that the
3750 * trace event in question used %s on a string that
3751 * was saved at the time of the event, but may not be
3752 * around when the trace is read. Use __string(),
3753 * __assign_str() and __get_str() helpers in the TRACE_EVENT()
3754 * instead. See samples/trace_events/trace-events-sample.h
3755 * for reference.
3756 */
3757 if (WARN_ONCE(!trace_safe_str(iter, str, star, len),
3758 "fmt: '%s' current_buffer: '%s'",
3759 fmt, seq_buf_str(&iter->seq.seq))) {
3760 int ret;
3761
3762 /* Try to safely read the string */
3763 if (star) {
3764 if (len + 1 > iter->fmt_size)
3765 len = iter->fmt_size - 1;
3766 if (len < 0)
3767 len = 0;
3768 ret = copy_from_kernel_nofault(iter->fmt, str, len);
3769 iter->fmt[len] = 0;
3770 star = false;
3771 } else {
3772 ret = strncpy_from_kernel_nofault(iter->fmt, str,
3773 iter->fmt_size);
3774 }
3775 if (ret < 0)
3776 trace_seq_printf(&iter->seq, "(0x%px)", str);
3777 else
3778 trace_seq_printf(&iter->seq, "(0x%px:%s)",
3779 str, iter->fmt);
3780 str = "[UNSAFE-MEMORY]";
3781 strcpy(iter->fmt, "%s");
3782 } else {
3783 strncpy(iter->fmt, p + i, j + 1);
3784 iter->fmt[j+1] = '\0';
3785 }
3786 if (star)
3787 trace_seq_printf(&iter->seq, iter->fmt, len, str);
3788 else
3789 trace_seq_printf(&iter->seq, iter->fmt, str);
3790
3791 p += i + j + 1;
3792 }
3793 print:
3794 if (*p)
3795 trace_seq_vprintf(&iter->seq, p, ap);
3796}
3797
3798const char *trace_event_format(struct trace_iterator *iter, const char *fmt)
3799{
3800 const char *p, *new_fmt;
3801 char *q;
3802
3803 if (WARN_ON_ONCE(!fmt))
3804 return fmt;
3805
3806 if (!iter->tr || iter->tr->trace_flags & TRACE_ITER_HASH_PTR)
3807 return fmt;
3808
3809 p = fmt;
3810 new_fmt = q = iter->fmt;
3811 while (*p) {
3812 if (unlikely(q - new_fmt + 3 > iter->fmt_size)) {
3813 if (!trace_iter_expand_format(iter))
3814 return fmt;
3815
3816 q += iter->fmt - new_fmt;
3817 new_fmt = iter->fmt;
3818 }
3819
3820 *q++ = *p++;
3821
3822 /* Replace %p with %px */
3823 if (p[-1] == '%') {
3824 if (p[0] == '%') {
3825 *q++ = *p++;
3826 } else if (p[0] == 'p' && !isalnum(p[1])) {
3827 *q++ = *p++;
3828 *q++ = 'x';
3829 }
3830 }
3831 }
3832 *q = '\0';
3833
3834 return new_fmt;
3835}
3836
3837#define STATIC_TEMP_BUF_SIZE 128
3838static char static_temp_buf[STATIC_TEMP_BUF_SIZE] __aligned(4);
3839
3840/* Find the next real entry, without updating the iterator itself */
3841struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
3842 int *ent_cpu, u64 *ent_ts)
3843{
3844 /* __find_next_entry will reset ent_size */
3845 int ent_size = iter->ent_size;
3846 struct trace_entry *entry;
3847
3848 /*
3849 * If called from ftrace_dump(), then the iter->temp buffer
3850 * will be the static_temp_buf and not created from kmalloc.
3851 * If the entry size is greater than the buffer, we can
3852 * not save it. Just return NULL in that case. This is only
3853 * used to add markers when two consecutive events' time
3854 * stamps have a large delta. See trace_print_lat_context()
3855 */
3856 if (iter->temp == static_temp_buf &&
3857 STATIC_TEMP_BUF_SIZE < ent_size)
3858 return NULL;
3859
3860 /*
3861 * The __find_next_entry() may call peek_next_entry(), which may
3862 * call ring_buffer_peek() that may make the contents of iter->ent
3863 * undefined. Need to copy iter->ent now.
3864 */
3865 if (iter->ent && iter->ent != iter->temp) {
3866 if ((!iter->temp || iter->temp_size < iter->ent_size) &&
3867 !WARN_ON_ONCE(iter->temp == static_temp_buf)) {
3868 void *temp;
3869 temp = kmalloc(iter->ent_size, GFP_KERNEL);
3870 if (!temp)
3871 return NULL;
3872 kfree(iter->temp);
3873 iter->temp = temp;
3874 iter->temp_size = iter->ent_size;
3875 }
3876 memcpy(iter->temp, iter->ent, iter->ent_size);
3877 iter->ent = iter->temp;
3878 }
3879 entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);
3880 /* Put back the original ent_size */
3881 iter->ent_size = ent_size;
3882
3883 return entry;
3884}
3885
3886/* Find the next real entry, and increment the iterator to the next entry */
3887void *trace_find_next_entry_inc(struct trace_iterator *iter)
3888{
3889 iter->ent = __find_next_entry(iter, &iter->cpu,
3890 &iter->lost_events, &iter->ts);
3891
3892 if (iter->ent)
3893 trace_iterator_increment(iter);
3894
3895 return iter->ent ? iter : NULL;
3896}
3897
3898static void trace_consume(struct trace_iterator *iter)
3899{
3900 ring_buffer_consume(iter->array_buffer->buffer, iter->cpu, &iter->ts,
3901 &iter->lost_events);
3902}
3903
3904static void *s_next(struct seq_file *m, void *v, loff_t *pos)
3905{
3906 struct trace_iterator *iter = m->private;
3907 int i = (int)*pos;
3908 void *ent;
3909
3910 WARN_ON_ONCE(iter->leftover);
3911
3912 (*pos)++;
3913
3914 /* can't go backwards */
3915 if (iter->idx > i)
3916 return NULL;
3917
3918 if (iter->idx < 0)
3919 ent = trace_find_next_entry_inc(iter);
3920 else
3921 ent = iter;
3922
3923 while (ent && iter->idx < i)
3924 ent = trace_find_next_entry_inc(iter);
3925
3926 iter->pos = *pos;
3927
3928 return ent;
3929}
3930
3931void tracing_iter_reset(struct trace_iterator *iter, int cpu)
3932{
3933 struct ring_buffer_iter *buf_iter;
3934 unsigned long entries = 0;
3935 u64 ts;
3936
3937 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = 0;
3938
3939 buf_iter = trace_buffer_iter(iter, cpu);
3940 if (!buf_iter)
3941 return;
3942
3943 ring_buffer_iter_reset(buf_iter);
3944
3945 /*
3946 * We could have the case with the max latency tracers
3947 * that a reset never took place on a cpu. This is evident
3948 * by the timestamp being before the start of the buffer.
3949 */
3950 while (ring_buffer_iter_peek(buf_iter, &ts)) {
3951 if (ts >= iter->array_buffer->time_start)
3952 break;
3953 entries++;
3954 ring_buffer_iter_advance(buf_iter);
3955 }
3956
3957 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = entries;
3958}
3959
3960/*
3961 * The current tracer is copied to avoid a global locking
3962 * all around.
3963 */
3964static void *s_start(struct seq_file *m, loff_t *pos)
3965{
3966 struct trace_iterator *iter = m->private;
3967 struct trace_array *tr = iter->tr;
3968 int cpu_file = iter->cpu_file;
3969 void *p = NULL;
3970 loff_t l = 0;
3971 int cpu;
3972
3973 mutex_lock(&trace_types_lock);
3974 if (unlikely(tr->current_trace != iter->trace)) {
3975 /* Close iter->trace before switching to the new current tracer */
3976 if (iter->trace->close)
3977 iter->trace->close(iter);
3978 iter->trace = tr->current_trace;
3979 /* Reopen the new current tracer */
3980 if (iter->trace->open)
3981 iter->trace->open(iter);
3982 }
3983 mutex_unlock(&trace_types_lock);
3984
3985#ifdef CONFIG_TRACER_MAX_TRACE
3986 if (iter->snapshot && iter->trace->use_max_tr)
3987 return ERR_PTR(-EBUSY);
3988#endif
3989
3990 if (*pos != iter->pos) {
3991 iter->ent = NULL;
3992 iter->cpu = 0;
3993 iter->idx = -1;
3994
3995 if (cpu_file == RING_BUFFER_ALL_CPUS) {
3996 for_each_tracing_cpu(cpu)
3997 tracing_iter_reset(iter, cpu);
3998 } else
3999 tracing_iter_reset(iter, cpu_file);
4000
4001 iter->leftover = 0;
4002 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
4003 ;
4004
4005 } else {
4006 /*
4007 * If we overflowed the seq_file before, then we want
4008 * to just reuse the trace_seq buffer again.
4009 */
4010 if (iter->leftover)
4011 p = iter;
4012 else {
4013 l = *pos - 1;
4014 p = s_next(m, p, &l);
4015 }
4016 }
4017
4018 trace_event_read_lock();
4019 trace_access_lock(cpu_file);
4020 return p;
4021}
4022
4023static void s_stop(struct seq_file *m, void *p)
4024{
4025 struct trace_iterator *iter = m->private;
4026
4027#ifdef CONFIG_TRACER_MAX_TRACE
4028 if (iter->snapshot && iter->trace->use_max_tr)
4029 return;
4030#endif
4031
4032 trace_access_unlock(iter->cpu_file);
4033 trace_event_read_unlock();
4034}
4035
4036static void
4037get_total_entries_cpu(struct array_buffer *buf, unsigned long *total,
4038 unsigned long *entries, int cpu)
4039{
4040 unsigned long count;
4041
4042 count = ring_buffer_entries_cpu(buf->buffer, cpu);
4043 /*
4044 * If this buffer has skipped entries, then we hold all
4045 * entries for the trace and we need to ignore the
4046 * ones before the time stamp.
4047 */
4048 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
4049 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
4050 /* total is the same as the entries */
4051 *total = count;
4052 } else
4053 *total = count +
4054 ring_buffer_overrun_cpu(buf->buffer, cpu);
4055 *entries = count;
4056}
4057
4058static void
4059get_total_entries(struct array_buffer *buf,
4060 unsigned long *total, unsigned long *entries)
4061{
4062 unsigned long t, e;
4063 int cpu;
4064
4065 *total = 0;
4066 *entries = 0;
4067
4068 for_each_tracing_cpu(cpu) {
4069 get_total_entries_cpu(buf, &t, &e, cpu);
4070 *total += t;
4071 *entries += e;
4072 }
4073}
4074
4075unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
4076{
4077 unsigned long total, entries;
4078
4079 if (!tr)
4080 tr = &global_trace;
4081
4082 get_total_entries_cpu(&tr->array_buffer, &total, &entries, cpu);
4083
4084 return entries;
4085}
4086
4087unsigned long trace_total_entries(struct trace_array *tr)
4088{
4089 unsigned long total, entries;
4090
4091 if (!tr)
4092 tr = &global_trace;
4093
4094 get_total_entries(&tr->array_buffer, &total, &entries);
4095
4096 return entries;
4097}
4098
4099static void print_lat_help_header(struct seq_file *m)
4100{
4101 seq_puts(m, "# _------=> CPU# \n"
4102 "# / _-----=> irqs-off/BH-disabled\n"
4103 "# | / _----=> need-resched \n"
4104 "# || / _---=> hardirq/softirq \n"
4105 "# ||| / _--=> preempt-depth \n"
4106 "# |||| / _-=> migrate-disable \n"
4107 "# ||||| / delay \n"
4108 "# cmd pid |||||| time | caller \n"
4109 "# \\ / |||||| \\ | / \n");
4110}
4111
4112static void print_event_info(struct array_buffer *buf, struct seq_file *m)
4113{
4114 unsigned long total;
4115 unsigned long entries;
4116
4117 get_total_entries(buf, &total, &entries);
4118 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
4119 entries, total, num_online_cpus());
4120 seq_puts(m, "#\n");
4121}
4122
4123static void print_func_help_header(struct array_buffer *buf, struct seq_file *m,
4124 unsigned int flags)
4125{
4126 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4127
4128 print_event_info(buf, m);
4129
4130 seq_printf(m, "# TASK-PID %s CPU# TIMESTAMP FUNCTION\n", tgid ? " TGID " : "");
4131 seq_printf(m, "# | | %s | | |\n", tgid ? " | " : "");
4132}
4133
4134static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file *m,
4135 unsigned int flags)
4136{
4137 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4138 static const char space[] = " ";
4139 int prec = tgid ? 12 : 2;
4140
4141 print_event_info(buf, m);
4142
4143 seq_printf(m, "# %.*s _-----=> irqs-off/BH-disabled\n", prec, space);
4144 seq_printf(m, "# %.*s / _----=> need-resched\n", prec, space);
4145 seq_printf(m, "# %.*s| / _---=> hardirq/softirq\n", prec, space);
4146 seq_printf(m, "# %.*s|| / _--=> preempt-depth\n", prec, space);
4147 seq_printf(m, "# %.*s||| / _-=> migrate-disable\n", prec, space);
4148 seq_printf(m, "# %.*s|||| / delay\n", prec, space);
4149 seq_printf(m, "# TASK-PID %.*s CPU# ||||| TIMESTAMP FUNCTION\n", prec, " TGID ");
4150 seq_printf(m, "# | | %.*s | ||||| | |\n", prec, " | ");
4151}
4152
4153void
4154print_trace_header(struct seq_file *m, struct trace_iterator *iter)
4155{
4156 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
4157 struct array_buffer *buf = iter->array_buffer;
4158 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
4159 struct tracer *type = iter->trace;
4160 unsigned long entries;
4161 unsigned long total;
4162 const char *name = type->name;
4163
4164 get_total_entries(buf, &total, &entries);
4165
4166 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
4167 name, init_utsname()->release);
4168 seq_puts(m, "# -----------------------------------"
4169 "---------------------------------\n");
4170 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
4171 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
4172 nsecs_to_usecs(data->saved_latency),
4173 entries,
4174 total,
4175 buf->cpu,
4176 preempt_model_none() ? "server" :
4177 preempt_model_voluntary() ? "desktop" :
4178 preempt_model_full() ? "preempt" :
4179 preempt_model_rt() ? "preempt_rt" :
4180 "unknown",
4181 /* These are reserved for later use */
4182 0, 0, 0, 0);
4183#ifdef CONFIG_SMP
4184 seq_printf(m, " #P:%d)\n", num_online_cpus());
4185#else
4186 seq_puts(m, ")\n");
4187#endif
4188 seq_puts(m, "# -----------------\n");
4189 seq_printf(m, "# | task: %.16s-%d "
4190 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
4191 data->comm, data->pid,
4192 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
4193 data->policy, data->rt_priority);
4194 seq_puts(m, "# -----------------\n");
4195
4196 if (data->critical_start) {
4197 seq_puts(m, "# => started at: ");
4198 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
4199 trace_print_seq(m, &iter->seq);
4200 seq_puts(m, "\n# => ended at: ");
4201 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
4202 trace_print_seq(m, &iter->seq);
4203 seq_puts(m, "\n#\n");
4204 }
4205
4206 seq_puts(m, "#\n");
4207}
4208
4209static void test_cpu_buff_start(struct trace_iterator *iter)
4210{
4211 struct trace_seq *s = &iter->seq;
4212 struct trace_array *tr = iter->tr;
4213
4214 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
4215 return;
4216
4217 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
4218 return;
4219
4220 if (cpumask_available(iter->started) &&
4221 cpumask_test_cpu(iter->cpu, iter->started))
4222 return;
4223
4224 if (per_cpu_ptr(iter->array_buffer->data, iter->cpu)->skipped_entries)
4225 return;
4226
4227 if (cpumask_available(iter->started))
4228 cpumask_set_cpu(iter->cpu, iter->started);
4229
4230 /* Don't print started cpu buffer for the first entry of the trace */
4231 if (iter->idx > 1)
4232 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
4233 iter->cpu);
4234}
4235
4236static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
4237{
4238 struct trace_array *tr = iter->tr;
4239 struct trace_seq *s = &iter->seq;
4240 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
4241 struct trace_entry *entry;
4242 struct trace_event *event;
4243
4244 entry = iter->ent;
4245
4246 test_cpu_buff_start(iter);
4247
4248 event = ftrace_find_event(entry->type);
4249
4250 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4251 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4252 trace_print_lat_context(iter);
4253 else
4254 trace_print_context(iter);
4255 }
4256
4257 if (trace_seq_has_overflowed(s))
4258 return TRACE_TYPE_PARTIAL_LINE;
4259
4260 if (event) {
4261 if (tr->trace_flags & TRACE_ITER_FIELDS)
4262 return print_event_fields(iter, event);
4263 return event->funcs->trace(iter, sym_flags, event);
4264 }
4265
4266 trace_seq_printf(s, "Unknown type %d\n", entry->type);
4267
4268 return trace_handle_return(s);
4269}
4270
4271static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
4272{
4273 struct trace_array *tr = iter->tr;
4274 struct trace_seq *s = &iter->seq;
4275 struct trace_entry *entry;
4276 struct trace_event *event;
4277
4278 entry = iter->ent;
4279
4280 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
4281 trace_seq_printf(s, "%d %d %llu ",
4282 entry->pid, iter->cpu, iter->ts);
4283
4284 if (trace_seq_has_overflowed(s))
4285 return TRACE_TYPE_PARTIAL_LINE;
4286
4287 event = ftrace_find_event(entry->type);
4288 if (event)
4289 return event->funcs->raw(iter, 0, event);
4290
4291 trace_seq_printf(s, "%d ?\n", entry->type);
4292
4293 return trace_handle_return(s);
4294}
4295
4296static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
4297{
4298 struct trace_array *tr = iter->tr;
4299 struct trace_seq *s = &iter->seq;
4300 unsigned char newline = '\n';
4301 struct trace_entry *entry;
4302 struct trace_event *event;
4303
4304 entry = iter->ent;
4305
4306 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4307 SEQ_PUT_HEX_FIELD(s, entry->pid);
4308 SEQ_PUT_HEX_FIELD(s, iter->cpu);
4309 SEQ_PUT_HEX_FIELD(s, iter->ts);
4310 if (trace_seq_has_overflowed(s))
4311 return TRACE_TYPE_PARTIAL_LINE;
4312 }
4313
4314 event = ftrace_find_event(entry->type);
4315 if (event) {
4316 enum print_line_t ret = event->funcs->hex(iter, 0, event);
4317 if (ret != TRACE_TYPE_HANDLED)
4318 return ret;
4319 }
4320
4321 SEQ_PUT_FIELD(s, newline);
4322
4323 return trace_handle_return(s);
4324}
4325
4326static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
4327{
4328 struct trace_array *tr = iter->tr;
4329 struct trace_seq *s = &iter->seq;
4330 struct trace_entry *entry;
4331 struct trace_event *event;
4332
4333 entry = iter->ent;
4334
4335 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4336 SEQ_PUT_FIELD(s, entry->pid);
4337 SEQ_PUT_FIELD(s, iter->cpu);
4338 SEQ_PUT_FIELD(s, iter->ts);
4339 if (trace_seq_has_overflowed(s))
4340 return TRACE_TYPE_PARTIAL_LINE;
4341 }
4342
4343 event = ftrace_find_event(entry->type);
4344 return event ? event->funcs->binary(iter, 0, event) :
4345 TRACE_TYPE_HANDLED;
4346}
4347
4348int trace_empty(struct trace_iterator *iter)
4349{
4350 struct ring_buffer_iter *buf_iter;
4351 int cpu;
4352
4353 /* If we are looking at one CPU buffer, only check that one */
4354 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4355 cpu = iter->cpu_file;
4356 buf_iter = trace_buffer_iter(iter, cpu);
4357 if (buf_iter) {
4358 if (!ring_buffer_iter_empty(buf_iter))
4359 return 0;
4360 } else {
4361 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4362 return 0;
4363 }
4364 return 1;
4365 }
4366
4367 for_each_tracing_cpu(cpu) {
4368 buf_iter = trace_buffer_iter(iter, cpu);
4369 if (buf_iter) {
4370 if (!ring_buffer_iter_empty(buf_iter))
4371 return 0;
4372 } else {
4373 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4374 return 0;
4375 }
4376 }
4377
4378 return 1;
4379}
4380
4381/* Called with trace_event_read_lock() held. */
4382enum print_line_t print_trace_line(struct trace_iterator *iter)
4383{
4384 struct trace_array *tr = iter->tr;
4385 unsigned long trace_flags = tr->trace_flags;
4386 enum print_line_t ret;
4387
4388 if (iter->lost_events) {
4389 if (iter->lost_events == (unsigned long)-1)
4390 trace_seq_printf(&iter->seq, "CPU:%d [LOST EVENTS]\n",
4391 iter->cpu);
4392 else
4393 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
4394 iter->cpu, iter->lost_events);
4395 if (trace_seq_has_overflowed(&iter->seq))
4396 return TRACE_TYPE_PARTIAL_LINE;
4397 }
4398
4399 if (iter->trace && iter->trace->print_line) {
4400 ret = iter->trace->print_line(iter);
4401 if (ret != TRACE_TYPE_UNHANDLED)
4402 return ret;
4403 }
4404
4405 if (iter->ent->type == TRACE_BPUTS &&
4406 trace_flags & TRACE_ITER_PRINTK &&
4407 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4408 return trace_print_bputs_msg_only(iter);
4409
4410 if (iter->ent->type == TRACE_BPRINT &&
4411 trace_flags & TRACE_ITER_PRINTK &&
4412 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4413 return trace_print_bprintk_msg_only(iter);
4414
4415 if (iter->ent->type == TRACE_PRINT &&
4416 trace_flags & TRACE_ITER_PRINTK &&
4417 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4418 return trace_print_printk_msg_only(iter);
4419
4420 if (trace_flags & TRACE_ITER_BIN)
4421 return print_bin_fmt(iter);
4422
4423 if (trace_flags & TRACE_ITER_HEX)
4424 return print_hex_fmt(iter);
4425
4426 if (trace_flags & TRACE_ITER_RAW)
4427 return print_raw_fmt(iter);
4428
4429 return print_trace_fmt(iter);
4430}
4431
4432void trace_latency_header(struct seq_file *m)
4433{
4434 struct trace_iterator *iter = m->private;
4435 struct trace_array *tr = iter->tr;
4436
4437 /* print nothing if the buffers are empty */
4438 if (trace_empty(iter))
4439 return;
4440
4441 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4442 print_trace_header(m, iter);
4443
4444 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
4445 print_lat_help_header(m);
4446}
4447
4448void trace_default_header(struct seq_file *m)
4449{
4450 struct trace_iterator *iter = m->private;
4451 struct trace_array *tr = iter->tr;
4452 unsigned long trace_flags = tr->trace_flags;
4453
4454 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
4455 return;
4456
4457 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
4458 /* print nothing if the buffers are empty */
4459 if (trace_empty(iter))
4460 return;
4461 print_trace_header(m, iter);
4462 if (!(trace_flags & TRACE_ITER_VERBOSE))
4463 print_lat_help_header(m);
4464 } else {
4465 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
4466 if (trace_flags & TRACE_ITER_IRQ_INFO)
4467 print_func_help_header_irq(iter->array_buffer,
4468 m, trace_flags);
4469 else
4470 print_func_help_header(iter->array_buffer, m,
4471 trace_flags);
4472 }
4473 }
4474}
4475
4476static void test_ftrace_alive(struct seq_file *m)
4477{
4478 if (!ftrace_is_dead())
4479 return;
4480 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
4481 "# MAY BE MISSING FUNCTION EVENTS\n");
4482}
4483
4484#ifdef CONFIG_TRACER_MAX_TRACE
4485static void show_snapshot_main_help(struct seq_file *m)
4486{
4487 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
4488 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4489 "# Takes a snapshot of the main buffer.\n"
4490 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
4491 "# (Doesn't have to be '2' works with any number that\n"
4492 "# is not a '0' or '1')\n");
4493}
4494
4495static void show_snapshot_percpu_help(struct seq_file *m)
4496{
4497 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
4498#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
4499 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4500 "# Takes a snapshot of the main buffer for this cpu.\n");
4501#else
4502 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
4503 "# Must use main snapshot file to allocate.\n");
4504#endif
4505 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
4506 "# (Doesn't have to be '2' works with any number that\n"
4507 "# is not a '0' or '1')\n");
4508}
4509
4510static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
4511{
4512 if (iter->tr->allocated_snapshot)
4513 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
4514 else
4515 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
4516
4517 seq_puts(m, "# Snapshot commands:\n");
4518 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4519 show_snapshot_main_help(m);
4520 else
4521 show_snapshot_percpu_help(m);
4522}
4523#else
4524/* Should never be called */
4525static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
4526#endif
4527
4528static int s_show(struct seq_file *m, void *v)
4529{
4530 struct trace_iterator *iter = v;
4531 int ret;
4532
4533 if (iter->ent == NULL) {
4534 if (iter->tr) {
4535 seq_printf(m, "# tracer: %s\n", iter->trace->name);
4536 seq_puts(m, "#\n");
4537 test_ftrace_alive(m);
4538 }
4539 if (iter->snapshot && trace_empty(iter))
4540 print_snapshot_help(m, iter);
4541 else if (iter->trace && iter->trace->print_header)
4542 iter->trace->print_header(m);
4543 else
4544 trace_default_header(m);
4545
4546 } else if (iter->leftover) {
4547 /*
4548 * If we filled the seq_file buffer earlier, we
4549 * want to just show it now.
4550 */
4551 ret = trace_print_seq(m, &iter->seq);
4552
4553 /* ret should this time be zero, but you never know */
4554 iter->leftover = ret;
4555
4556 } else {
4557 ret = print_trace_line(iter);
4558 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4559 iter->seq.full = 0;
4560 trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
4561 }
4562 ret = trace_print_seq(m, &iter->seq);
4563 /*
4564 * If we overflow the seq_file buffer, then it will
4565 * ask us for this data again at start up.
4566 * Use that instead.
4567 * ret is 0 if seq_file write succeeded.
4568 * -1 otherwise.
4569 */
4570 iter->leftover = ret;
4571 }
4572
4573 return 0;
4574}
4575
4576/*
4577 * Should be used after trace_array_get(), trace_types_lock
4578 * ensures that i_cdev was already initialized.
4579 */
4580static inline int tracing_get_cpu(struct inode *inode)
4581{
4582 if (inode->i_cdev) /* See trace_create_cpu_file() */
4583 return (long)inode->i_cdev - 1;
4584 return RING_BUFFER_ALL_CPUS;
4585}
4586
4587static const struct seq_operations tracer_seq_ops = {
4588 .start = s_start,
4589 .next = s_next,
4590 .stop = s_stop,
4591 .show = s_show,
4592};
4593
4594/*
4595 * Note, as iter itself can be allocated and freed in different
4596 * ways, this function is only used to free its content, and not
4597 * the iterator itself. The only requirement to all the allocations
4598 * is that it must zero all fields (kzalloc), as freeing works with
4599 * ethier allocated content or NULL.
4600 */
4601static void free_trace_iter_content(struct trace_iterator *iter)
4602{
4603 /* The fmt is either NULL, allocated or points to static_fmt_buf */
4604 if (iter->fmt != static_fmt_buf)
4605 kfree(iter->fmt);
4606
4607 kfree(iter->temp);
4608 kfree(iter->buffer_iter);
4609 mutex_destroy(&iter->mutex);
4610 free_cpumask_var(iter->started);
4611}
4612
4613static struct trace_iterator *
4614__tracing_open(struct inode *inode, struct file *file, bool snapshot)
4615{
4616 struct trace_array *tr = inode->i_private;
4617 struct trace_iterator *iter;
4618 int cpu;
4619
4620 if (tracing_disabled)
4621 return ERR_PTR(-ENODEV);
4622
4623 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
4624 if (!iter)
4625 return ERR_PTR(-ENOMEM);
4626
4627 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
4628 GFP_KERNEL);
4629 if (!iter->buffer_iter)
4630 goto release;
4631
4632 /*
4633 * trace_find_next_entry() may need to save off iter->ent.
4634 * It will place it into the iter->temp buffer. As most
4635 * events are less than 128, allocate a buffer of that size.
4636 * If one is greater, then trace_find_next_entry() will
4637 * allocate a new buffer to adjust for the bigger iter->ent.
4638 * It's not critical if it fails to get allocated here.
4639 */
4640 iter->temp = kmalloc(128, GFP_KERNEL);
4641 if (iter->temp)
4642 iter->temp_size = 128;
4643
4644 /*
4645 * trace_event_printf() may need to modify given format
4646 * string to replace %p with %px so that it shows real address
4647 * instead of hash value. However, that is only for the event
4648 * tracing, other tracer may not need. Defer the allocation
4649 * until it is needed.
4650 */
4651 iter->fmt = NULL;
4652 iter->fmt_size = 0;
4653
4654 mutex_lock(&trace_types_lock);
4655 iter->trace = tr->current_trace;
4656
4657 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
4658 goto fail;
4659
4660 iter->tr = tr;
4661
4662#ifdef CONFIG_TRACER_MAX_TRACE
4663 /* Currently only the top directory has a snapshot */
4664 if (tr->current_trace->print_max || snapshot)
4665 iter->array_buffer = &tr->max_buffer;
4666 else
4667#endif
4668 iter->array_buffer = &tr->array_buffer;
4669 iter->snapshot = snapshot;
4670 iter->pos = -1;
4671 iter->cpu_file = tracing_get_cpu(inode);
4672 mutex_init(&iter->mutex);
4673
4674 /* Notify the tracer early; before we stop tracing. */
4675 if (iter->trace->open)
4676 iter->trace->open(iter);
4677
4678 /* Annotate start of buffers if we had overruns */
4679 if (ring_buffer_overruns(iter->array_buffer->buffer))
4680 iter->iter_flags |= TRACE_FILE_ANNOTATE;
4681
4682 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4683 if (trace_clocks[tr->clock_id].in_ns)
4684 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4685
4686 /*
4687 * If pause-on-trace is enabled, then stop the trace while
4688 * dumping, unless this is the "snapshot" file
4689 */
4690 if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE))
4691 tracing_stop_tr(tr);
4692
4693 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
4694 for_each_tracing_cpu(cpu) {
4695 iter->buffer_iter[cpu] =
4696 ring_buffer_read_prepare(iter->array_buffer->buffer,
4697 cpu, GFP_KERNEL);
4698 }
4699 ring_buffer_read_prepare_sync();
4700 for_each_tracing_cpu(cpu) {
4701 ring_buffer_read_start(iter->buffer_iter[cpu]);
4702 tracing_iter_reset(iter, cpu);
4703 }
4704 } else {
4705 cpu = iter->cpu_file;
4706 iter->buffer_iter[cpu] =
4707 ring_buffer_read_prepare(iter->array_buffer->buffer,
4708 cpu, GFP_KERNEL);
4709 ring_buffer_read_prepare_sync();
4710 ring_buffer_read_start(iter->buffer_iter[cpu]);
4711 tracing_iter_reset(iter, cpu);
4712 }
4713
4714 mutex_unlock(&trace_types_lock);
4715
4716 return iter;
4717
4718 fail:
4719 mutex_unlock(&trace_types_lock);
4720 free_trace_iter_content(iter);
4721release:
4722 seq_release_private(inode, file);
4723 return ERR_PTR(-ENOMEM);
4724}
4725
4726int tracing_open_generic(struct inode *inode, struct file *filp)
4727{
4728 int ret;
4729
4730 ret = tracing_check_open_get_tr(NULL);
4731 if (ret)
4732 return ret;
4733
4734 filp->private_data = inode->i_private;
4735 return 0;
4736}
4737
4738bool tracing_is_disabled(void)
4739{
4740 return (tracing_disabled) ? true: false;
4741}
4742
4743/*
4744 * Open and update trace_array ref count.
4745 * Must have the current trace_array passed to it.
4746 */
4747int tracing_open_generic_tr(struct inode *inode, struct file *filp)
4748{
4749 struct trace_array *tr = inode->i_private;
4750 int ret;
4751
4752 ret = tracing_check_open_get_tr(tr);
4753 if (ret)
4754 return ret;
4755
4756 filp->private_data = inode->i_private;
4757
4758 return 0;
4759}
4760
4761/*
4762 * The private pointer of the inode is the trace_event_file.
4763 * Update the tr ref count associated to it.
4764 */
4765int tracing_open_file_tr(struct inode *inode, struct file *filp)
4766{
4767 struct trace_event_file *file = inode->i_private;
4768 int ret;
4769
4770 ret = tracing_check_open_get_tr(file->tr);
4771 if (ret)
4772 return ret;
4773
4774 mutex_lock(&event_mutex);
4775
4776 /* Fail if the file is marked for removal */
4777 if (file->flags & EVENT_FILE_FL_FREED) {
4778 trace_array_put(file->tr);
4779 ret = -ENODEV;
4780 } else {
4781 event_file_get(file);
4782 }
4783
4784 mutex_unlock(&event_mutex);
4785 if (ret)
4786 return ret;
4787
4788 filp->private_data = inode->i_private;
4789
4790 return 0;
4791}
4792
4793int tracing_release_file_tr(struct inode *inode, struct file *filp)
4794{
4795 struct trace_event_file *file = inode->i_private;
4796
4797 trace_array_put(file->tr);
4798 event_file_put(file);
4799
4800 return 0;
4801}
4802
4803int tracing_single_release_file_tr(struct inode *inode, struct file *filp)
4804{
4805 tracing_release_file_tr(inode, filp);
4806 return single_release(inode, filp);
4807}
4808
4809static int tracing_mark_open(struct inode *inode, struct file *filp)
4810{
4811 stream_open(inode, filp);
4812 return tracing_open_generic_tr(inode, filp);
4813}
4814
4815static int tracing_release(struct inode *inode, struct file *file)
4816{
4817 struct trace_array *tr = inode->i_private;
4818 struct seq_file *m = file->private_data;
4819 struct trace_iterator *iter;
4820 int cpu;
4821
4822 if (!(file->f_mode & FMODE_READ)) {
4823 trace_array_put(tr);
4824 return 0;
4825 }
4826
4827 /* Writes do not use seq_file */
4828 iter = m->private;
4829 mutex_lock(&trace_types_lock);
4830
4831 for_each_tracing_cpu(cpu) {
4832 if (iter->buffer_iter[cpu])
4833 ring_buffer_read_finish(iter->buffer_iter[cpu]);
4834 }
4835
4836 if (iter->trace && iter->trace->close)
4837 iter->trace->close(iter);
4838
4839 if (!iter->snapshot && tr->stop_count)
4840 /* reenable tracing if it was previously enabled */
4841 tracing_start_tr(tr);
4842
4843 __trace_array_put(tr);
4844
4845 mutex_unlock(&trace_types_lock);
4846
4847 free_trace_iter_content(iter);
4848 seq_release_private(inode, file);
4849
4850 return 0;
4851}
4852
4853int tracing_release_generic_tr(struct inode *inode, struct file *file)
4854{
4855 struct trace_array *tr = inode->i_private;
4856
4857 trace_array_put(tr);
4858 return 0;
4859}
4860
4861static int tracing_single_release_tr(struct inode *inode, struct file *file)
4862{
4863 struct trace_array *tr = inode->i_private;
4864
4865 trace_array_put(tr);
4866
4867 return single_release(inode, file);
4868}
4869
4870static int tracing_open(struct inode *inode, struct file *file)
4871{
4872 struct trace_array *tr = inode->i_private;
4873 struct trace_iterator *iter;
4874 int ret;
4875
4876 ret = tracing_check_open_get_tr(tr);
4877 if (ret)
4878 return ret;
4879
4880 /* If this file was open for write, then erase contents */
4881 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
4882 int cpu = tracing_get_cpu(inode);
4883 struct array_buffer *trace_buf = &tr->array_buffer;
4884
4885#ifdef CONFIG_TRACER_MAX_TRACE
4886 if (tr->current_trace->print_max)
4887 trace_buf = &tr->max_buffer;
4888#endif
4889
4890 if (cpu == RING_BUFFER_ALL_CPUS)
4891 tracing_reset_online_cpus(trace_buf);
4892 else
4893 tracing_reset_cpu(trace_buf, cpu);
4894 }
4895
4896 if (file->f_mode & FMODE_READ) {
4897 iter = __tracing_open(inode, file, false);
4898 if (IS_ERR(iter))
4899 ret = PTR_ERR(iter);
4900 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
4901 iter->iter_flags |= TRACE_FILE_LAT_FMT;
4902 }
4903
4904 if (ret < 0)
4905 trace_array_put(tr);
4906
4907 return ret;
4908}
4909
4910/*
4911 * Some tracers are not suitable for instance buffers.
4912 * A tracer is always available for the global array (toplevel)
4913 * or if it explicitly states that it is.
4914 */
4915static bool
4916trace_ok_for_array(struct tracer *t, struct trace_array *tr)
4917{
4918 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
4919}
4920
4921/* Find the next tracer that this trace array may use */
4922static struct tracer *
4923get_tracer_for_array(struct trace_array *tr, struct tracer *t)
4924{
4925 while (t && !trace_ok_for_array(t, tr))
4926 t = t->next;
4927
4928 return t;
4929}
4930
4931static void *
4932t_next(struct seq_file *m, void *v, loff_t *pos)
4933{
4934 struct trace_array *tr = m->private;
4935 struct tracer *t = v;
4936
4937 (*pos)++;
4938
4939 if (t)
4940 t = get_tracer_for_array(tr, t->next);
4941
4942 return t;
4943}
4944
4945static void *t_start(struct seq_file *m, loff_t *pos)
4946{
4947 struct trace_array *tr = m->private;
4948 struct tracer *t;
4949 loff_t l = 0;
4950
4951 mutex_lock(&trace_types_lock);
4952
4953 t = get_tracer_for_array(tr, trace_types);
4954 for (; t && l < *pos; t = t_next(m, t, &l))
4955 ;
4956
4957 return t;
4958}
4959
4960static void t_stop(struct seq_file *m, void *p)
4961{
4962 mutex_unlock(&trace_types_lock);
4963}
4964
4965static int t_show(struct seq_file *m, void *v)
4966{
4967 struct tracer *t = v;
4968
4969 if (!t)
4970 return 0;
4971
4972 seq_puts(m, t->name);
4973 if (t->next)
4974 seq_putc(m, ' ');
4975 else
4976 seq_putc(m, '\n');
4977
4978 return 0;
4979}
4980
4981static const struct seq_operations show_traces_seq_ops = {
4982 .start = t_start,
4983 .next = t_next,
4984 .stop = t_stop,
4985 .show = t_show,
4986};
4987
4988static int show_traces_open(struct inode *inode, struct file *file)
4989{
4990 struct trace_array *tr = inode->i_private;
4991 struct seq_file *m;
4992 int ret;
4993
4994 ret = tracing_check_open_get_tr(tr);
4995 if (ret)
4996 return ret;
4997
4998 ret = seq_open(file, &show_traces_seq_ops);
4999 if (ret) {
5000 trace_array_put(tr);
5001 return ret;
5002 }
5003
5004 m = file->private_data;
5005 m->private = tr;
5006
5007 return 0;
5008}
5009
5010static int show_traces_release(struct inode *inode, struct file *file)
5011{
5012 struct trace_array *tr = inode->i_private;
5013
5014 trace_array_put(tr);
5015 return seq_release(inode, file);
5016}
5017
5018static ssize_t
5019tracing_write_stub(struct file *filp, const char __user *ubuf,
5020 size_t count, loff_t *ppos)
5021{
5022 return count;
5023}
5024
5025loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
5026{
5027 int ret;
5028
5029 if (file->f_mode & FMODE_READ)
5030 ret = seq_lseek(file, offset, whence);
5031 else
5032 file->f_pos = ret = 0;
5033
5034 return ret;
5035}
5036
5037static const struct file_operations tracing_fops = {
5038 .open = tracing_open,
5039 .read = seq_read,
5040 .read_iter = seq_read_iter,
5041 .splice_read = copy_splice_read,
5042 .write = tracing_write_stub,
5043 .llseek = tracing_lseek,
5044 .release = tracing_release,
5045};
5046
5047static const struct file_operations show_traces_fops = {
5048 .open = show_traces_open,
5049 .read = seq_read,
5050 .llseek = seq_lseek,
5051 .release = show_traces_release,
5052};
5053
5054static ssize_t
5055tracing_cpumask_read(struct file *filp, char __user *ubuf,
5056 size_t count, loff_t *ppos)
5057{
5058 struct trace_array *tr = file_inode(filp)->i_private;
5059 char *mask_str;
5060 int len;
5061
5062 len = snprintf(NULL, 0, "%*pb\n",
5063 cpumask_pr_args(tr->tracing_cpumask)) + 1;
5064 mask_str = kmalloc(len, GFP_KERNEL);
5065 if (!mask_str)
5066 return -ENOMEM;
5067
5068 len = snprintf(mask_str, len, "%*pb\n",
5069 cpumask_pr_args(tr->tracing_cpumask));
5070 if (len >= count) {
5071 count = -EINVAL;
5072 goto out_err;
5073 }
5074 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
5075
5076out_err:
5077 kfree(mask_str);
5078
5079 return count;
5080}
5081
5082int tracing_set_cpumask(struct trace_array *tr,
5083 cpumask_var_t tracing_cpumask_new)
5084{
5085 int cpu;
5086
5087 if (!tr)
5088 return -EINVAL;
5089
5090 local_irq_disable();
5091 arch_spin_lock(&tr->max_lock);
5092 for_each_tracing_cpu(cpu) {
5093 /*
5094 * Increase/decrease the disabled counter if we are
5095 * about to flip a bit in the cpumask:
5096 */
5097 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5098 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5099 atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5100 ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
5101#ifdef CONFIG_TRACER_MAX_TRACE
5102 ring_buffer_record_disable_cpu(tr->max_buffer.buffer, cpu);
5103#endif
5104 }
5105 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5106 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5107 atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5108 ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
5109#ifdef CONFIG_TRACER_MAX_TRACE
5110 ring_buffer_record_enable_cpu(tr->max_buffer.buffer, cpu);
5111#endif
5112 }
5113 }
5114 arch_spin_unlock(&tr->max_lock);
5115 local_irq_enable();
5116
5117 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
5118
5119 return 0;
5120}
5121
5122static ssize_t
5123tracing_cpumask_write(struct file *filp, const char __user *ubuf,
5124 size_t count, loff_t *ppos)
5125{
5126 struct trace_array *tr = file_inode(filp)->i_private;
5127 cpumask_var_t tracing_cpumask_new;
5128 int err;
5129
5130 if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
5131 return -ENOMEM;
5132
5133 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
5134 if (err)
5135 goto err_free;
5136
5137 err = tracing_set_cpumask(tr, tracing_cpumask_new);
5138 if (err)
5139 goto err_free;
5140
5141 free_cpumask_var(tracing_cpumask_new);
5142
5143 return count;
5144
5145err_free:
5146 free_cpumask_var(tracing_cpumask_new);
5147
5148 return err;
5149}
5150
5151static const struct file_operations tracing_cpumask_fops = {
5152 .open = tracing_open_generic_tr,
5153 .read = tracing_cpumask_read,
5154 .write = tracing_cpumask_write,
5155 .release = tracing_release_generic_tr,
5156 .llseek = generic_file_llseek,
5157};
5158
5159static int tracing_trace_options_show(struct seq_file *m, void *v)
5160{
5161 struct tracer_opt *trace_opts;
5162 struct trace_array *tr = m->private;
5163 u32 tracer_flags;
5164 int i;
5165
5166 mutex_lock(&trace_types_lock);
5167 tracer_flags = tr->current_trace->flags->val;
5168 trace_opts = tr->current_trace->flags->opts;
5169
5170 for (i = 0; trace_options[i]; i++) {
5171 if (tr->trace_flags & (1 << i))
5172 seq_printf(m, "%s\n", trace_options[i]);
5173 else
5174 seq_printf(m, "no%s\n", trace_options[i]);
5175 }
5176
5177 for (i = 0; trace_opts[i].name; i++) {
5178 if (tracer_flags & trace_opts[i].bit)
5179 seq_printf(m, "%s\n", trace_opts[i].name);
5180 else
5181 seq_printf(m, "no%s\n", trace_opts[i].name);
5182 }
5183 mutex_unlock(&trace_types_lock);
5184
5185 return 0;
5186}
5187
5188static int __set_tracer_option(struct trace_array *tr,
5189 struct tracer_flags *tracer_flags,
5190 struct tracer_opt *opts, int neg)
5191{
5192 struct tracer *trace = tracer_flags->trace;
5193 int ret;
5194
5195 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
5196 if (ret)
5197 return ret;
5198
5199 if (neg)
5200 tracer_flags->val &= ~opts->bit;
5201 else
5202 tracer_flags->val |= opts->bit;
5203 return 0;
5204}
5205
5206/* Try to assign a tracer specific option */
5207static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
5208{
5209 struct tracer *trace = tr->current_trace;
5210 struct tracer_flags *tracer_flags = trace->flags;
5211 struct tracer_opt *opts = NULL;
5212 int i;
5213
5214 for (i = 0; tracer_flags->opts[i].name; i++) {
5215 opts = &tracer_flags->opts[i];
5216
5217 if (strcmp(cmp, opts->name) == 0)
5218 return __set_tracer_option(tr, trace->flags, opts, neg);
5219 }
5220
5221 return -EINVAL;
5222}
5223
5224/* Some tracers require overwrite to stay enabled */
5225int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
5226{
5227 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
5228 return -1;
5229
5230 return 0;
5231}
5232
5233int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
5234{
5235 if ((mask == TRACE_ITER_RECORD_TGID) ||
5236 (mask == TRACE_ITER_RECORD_CMD))
5237 lockdep_assert_held(&event_mutex);
5238
5239 /* do nothing if flag is already set */
5240 if (!!(tr->trace_flags & mask) == !!enabled)
5241 return 0;
5242
5243 /* Give the tracer a chance to approve the change */
5244 if (tr->current_trace->flag_changed)
5245 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
5246 return -EINVAL;
5247
5248 if (enabled)
5249 tr->trace_flags |= mask;
5250 else
5251 tr->trace_flags &= ~mask;
5252
5253 if (mask == TRACE_ITER_RECORD_CMD)
5254 trace_event_enable_cmd_record(enabled);
5255
5256 if (mask == TRACE_ITER_RECORD_TGID) {
5257
5258 if (trace_alloc_tgid_map() < 0) {
5259 tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
5260 return -ENOMEM;
5261 }
5262
5263 trace_event_enable_tgid_record(enabled);
5264 }
5265
5266 if (mask == TRACE_ITER_EVENT_FORK)
5267 trace_event_follow_fork(tr, enabled);
5268
5269 if (mask == TRACE_ITER_FUNC_FORK)
5270 ftrace_pid_follow_fork(tr, enabled);
5271
5272 if (mask == TRACE_ITER_OVERWRITE) {
5273 ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled);
5274#ifdef CONFIG_TRACER_MAX_TRACE
5275 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
5276#endif
5277 }
5278
5279 if (mask == TRACE_ITER_PRINTK) {
5280 trace_printk_start_stop_comm(enabled);
5281 trace_printk_control(enabled);
5282 }
5283
5284 return 0;
5285}
5286
5287int trace_set_options(struct trace_array *tr, char *option)
5288{
5289 char *cmp;
5290 int neg = 0;
5291 int ret;
5292 size_t orig_len = strlen(option);
5293 int len;
5294
5295 cmp = strstrip(option);
5296
5297 len = str_has_prefix(cmp, "no");
5298 if (len)
5299 neg = 1;
5300
5301 cmp += len;
5302
5303 mutex_lock(&event_mutex);
5304 mutex_lock(&trace_types_lock);
5305
5306 ret = match_string(trace_options, -1, cmp);
5307 /* If no option could be set, test the specific tracer options */
5308 if (ret < 0)
5309 ret = set_tracer_option(tr, cmp, neg);
5310 else
5311 ret = set_tracer_flag(tr, 1 << ret, !neg);
5312
5313 mutex_unlock(&trace_types_lock);
5314 mutex_unlock(&event_mutex);
5315
5316 /*
5317 * If the first trailing whitespace is replaced with '\0' by strstrip,
5318 * turn it back into a space.
5319 */
5320 if (orig_len > strlen(option))
5321 option[strlen(option)] = ' ';
5322
5323 return ret;
5324}
5325
5326static void __init apply_trace_boot_options(void)
5327{
5328 char *buf = trace_boot_options_buf;
5329 char *option;
5330
5331 while (true) {
5332 option = strsep(&buf, ",");
5333
5334 if (!option)
5335 break;
5336
5337 if (*option)
5338 trace_set_options(&global_trace, option);
5339
5340 /* Put back the comma to allow this to be called again */
5341 if (buf)
5342 *(buf - 1) = ',';
5343 }
5344}
5345
5346static ssize_t
5347tracing_trace_options_write(struct file *filp, const char __user *ubuf,
5348 size_t cnt, loff_t *ppos)
5349{
5350 struct seq_file *m = filp->private_data;
5351 struct trace_array *tr = m->private;
5352 char buf[64];
5353 int ret;
5354
5355 if (cnt >= sizeof(buf))
5356 return -EINVAL;
5357
5358 if (copy_from_user(buf, ubuf, cnt))
5359 return -EFAULT;
5360
5361 buf[cnt] = 0;
5362
5363 ret = trace_set_options(tr, buf);
5364 if (ret < 0)
5365 return ret;
5366
5367 *ppos += cnt;
5368
5369 return cnt;
5370}
5371
5372static int tracing_trace_options_open(struct inode *inode, struct file *file)
5373{
5374 struct trace_array *tr = inode->i_private;
5375 int ret;
5376
5377 ret = tracing_check_open_get_tr(tr);
5378 if (ret)
5379 return ret;
5380
5381 ret = single_open(file, tracing_trace_options_show, inode->i_private);
5382 if (ret < 0)
5383 trace_array_put(tr);
5384
5385 return ret;
5386}
5387
5388static const struct file_operations tracing_iter_fops = {
5389 .open = tracing_trace_options_open,
5390 .read = seq_read,
5391 .llseek = seq_lseek,
5392 .release = tracing_single_release_tr,
5393 .write = tracing_trace_options_write,
5394};
5395
5396static const char readme_msg[] =
5397 "tracing mini-HOWTO:\n\n"
5398 "# echo 0 > tracing_on : quick way to disable tracing\n"
5399 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
5400 " Important files:\n"
5401 " trace\t\t\t- The static contents of the buffer\n"
5402 "\t\t\t To clear the buffer write into this file: echo > trace\n"
5403 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
5404 " current_tracer\t- function and latency tracers\n"
5405 " available_tracers\t- list of configured tracers for current_tracer\n"
5406 " error_log\t- error log for failed commands (that support it)\n"
5407 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
5408 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
5409 " trace_clock\t\t- change the clock used to order events\n"
5410 " local: Per cpu clock but may not be synced across CPUs\n"
5411 " global: Synced across CPUs but slows tracing down.\n"
5412 " counter: Not a clock, but just an increment\n"
5413 " uptime: Jiffy counter from time of boot\n"
5414 " perf: Same clock that perf events use\n"
5415#ifdef CONFIG_X86_64
5416 " x86-tsc: TSC cycle counter\n"
5417#endif
5418 "\n timestamp_mode\t- view the mode used to timestamp events\n"
5419 " delta: Delta difference against a buffer-wide timestamp\n"
5420 " absolute: Absolute (standalone) timestamp\n"
5421 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
5422 "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
5423 " tracing_cpumask\t- Limit which CPUs to trace\n"
5424 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
5425 "\t\t\t Remove sub-buffer with rmdir\n"
5426 " trace_options\t\t- Set format or modify how tracing happens\n"
5427 "\t\t\t Disable an option by prefixing 'no' to the\n"
5428 "\t\t\t option name\n"
5429 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
5430#ifdef CONFIG_DYNAMIC_FTRACE
5431 "\n available_filter_functions - list of functions that can be filtered on\n"
5432 " set_ftrace_filter\t- echo function name in here to only trace these\n"
5433 "\t\t\t functions\n"
5434 "\t accepts: func_full_name or glob-matching-pattern\n"
5435 "\t modules: Can select a group via module\n"
5436 "\t Format: :mod:<module-name>\n"
5437 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
5438 "\t triggers: a command to perform when function is hit\n"
5439 "\t Format: <function>:<trigger>[:count]\n"
5440 "\t trigger: traceon, traceoff\n"
5441 "\t\t enable_event:<system>:<event>\n"
5442 "\t\t disable_event:<system>:<event>\n"
5443#ifdef CONFIG_STACKTRACE
5444 "\t\t stacktrace\n"
5445#endif
5446#ifdef CONFIG_TRACER_SNAPSHOT
5447 "\t\t snapshot\n"
5448#endif
5449 "\t\t dump\n"
5450 "\t\t cpudump\n"
5451 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
5452 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
5453 "\t The first one will disable tracing every time do_fault is hit\n"
5454 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
5455 "\t The first time do trap is hit and it disables tracing, the\n"
5456 "\t counter will decrement to 2. If tracing is already disabled,\n"
5457 "\t the counter will not decrement. It only decrements when the\n"
5458 "\t trigger did work\n"
5459 "\t To remove trigger without count:\n"
5460 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
5461 "\t To remove trigger with a count:\n"
5462 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
5463 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
5464 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
5465 "\t modules: Can select a group via module command :mod:\n"
5466 "\t Does not accept triggers\n"
5467#endif /* CONFIG_DYNAMIC_FTRACE */
5468#ifdef CONFIG_FUNCTION_TRACER
5469 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
5470 "\t\t (function)\n"
5471 " set_ftrace_notrace_pid\t- Write pid(s) to not function trace those pids\n"
5472 "\t\t (function)\n"
5473#endif
5474#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5475 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
5476 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
5477 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
5478#endif
5479#ifdef CONFIG_TRACER_SNAPSHOT
5480 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
5481 "\t\t\t snapshot buffer. Read the contents for more\n"
5482 "\t\t\t information\n"
5483#endif
5484#ifdef CONFIG_STACK_TRACER
5485 " stack_trace\t\t- Shows the max stack trace when active\n"
5486 " stack_max_size\t- Shows current max stack size that was traced\n"
5487 "\t\t\t Write into this file to reset the max size (trigger a\n"
5488 "\t\t\t new trace)\n"
5489#ifdef CONFIG_DYNAMIC_FTRACE
5490 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
5491 "\t\t\t traces\n"
5492#endif
5493#endif /* CONFIG_STACK_TRACER */
5494#ifdef CONFIG_DYNAMIC_EVENTS
5495 " dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
5496 "\t\t\t Write into this file to define/undefine new trace events.\n"
5497#endif
5498#ifdef CONFIG_KPROBE_EVENTS
5499 " kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
5500 "\t\t\t Write into this file to define/undefine new trace events.\n"
5501#endif
5502#ifdef CONFIG_UPROBE_EVENTS
5503 " uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
5504 "\t\t\t Write into this file to define/undefine new trace events.\n"
5505#endif
5506#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) || \
5507 defined(CONFIG_FPROBE_EVENTS)
5508 "\t accepts: event-definitions (one definition per line)\n"
5509#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
5510 "\t Format: p[:[<group>/][<event>]] <place> [<args>]\n"
5511 "\t r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
5512#endif
5513#ifdef CONFIG_FPROBE_EVENTS
5514 "\t f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n"
5515 "\t t[:[<group>/][<event>]] <tracepoint> [<args>]\n"
5516#endif
5517#ifdef CONFIG_HIST_TRIGGERS
5518 "\t s:[synthetic/]<event> <field> [<field>]\n"
5519#endif
5520 "\t e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>] [if <filter>]\n"
5521 "\t -:[<group>/][<event>]\n"
5522#ifdef CONFIG_KPROBE_EVENTS
5523 "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
5524 "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n"
5525#endif
5526#ifdef CONFIG_UPROBE_EVENTS
5527 " place (uprobe): <path>:<offset>[%return][(ref_ctr_offset)]\n"
5528#endif
5529 "\t args: <name>=fetcharg[:type]\n"
5530 "\t fetcharg: (%<register>|$<efield>), @<address>, @<symbol>[+|-<offset>],\n"
5531#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
5532 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
5533#ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
5534 "\t <argname>[->field[->field|.field...]],\n"
5535#endif
5536#else
5537 "\t $stack<index>, $stack, $retval, $comm,\n"
5538#endif
5539 "\t +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
5540 "\t kernel return probes support: $retval, $arg<N>, $comm\n"
5541 "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, char, string, symbol,\n"
5542 "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
5543 "\t symstr, <type>\\[<array-size>\\]\n"
5544#ifdef CONFIG_HIST_TRIGGERS
5545 "\t field: <stype> <name>;\n"
5546 "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
5547 "\t [unsigned] char/int/long\n"
5548#endif
5549 "\t efield: For event probes ('e' types), the field is on of the fields\n"
5550 "\t of the <attached-group>/<attached-event>.\n"
5551#endif
5552 " events/\t\t- Directory containing all trace event subsystems:\n"
5553 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
5554 " events/<system>/\t- Directory containing all trace events for <system>:\n"
5555 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
5556 "\t\t\t events\n"
5557 " filter\t\t- If set, only events passing filter are traced\n"
5558 " events/<system>/<event>/\t- Directory containing control files for\n"
5559 "\t\t\t <event>:\n"
5560 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
5561 " filter\t\t- If set, only events passing filter are traced\n"
5562 " trigger\t\t- If set, a command to perform when event is hit\n"
5563 "\t Format: <trigger>[:count][if <filter>]\n"
5564 "\t trigger: traceon, traceoff\n"
5565 "\t enable_event:<system>:<event>\n"
5566 "\t disable_event:<system>:<event>\n"
5567#ifdef CONFIG_HIST_TRIGGERS
5568 "\t enable_hist:<system>:<event>\n"
5569 "\t disable_hist:<system>:<event>\n"
5570#endif
5571#ifdef CONFIG_STACKTRACE
5572 "\t\t stacktrace\n"
5573#endif
5574#ifdef CONFIG_TRACER_SNAPSHOT
5575 "\t\t snapshot\n"
5576#endif
5577#ifdef CONFIG_HIST_TRIGGERS
5578 "\t\t hist (see below)\n"
5579#endif
5580 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
5581 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
5582 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
5583 "\t events/block/block_unplug/trigger\n"
5584 "\t The first disables tracing every time block_unplug is hit.\n"
5585 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
5586 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
5587 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
5588 "\t Like function triggers, the counter is only decremented if it\n"
5589 "\t enabled or disabled tracing.\n"
5590 "\t To remove a trigger without a count:\n"
5591 "\t echo '!<trigger> > <system>/<event>/trigger\n"
5592 "\t To remove a trigger with a count:\n"
5593 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
5594 "\t Filters can be ignored when removing a trigger.\n"
5595#ifdef CONFIG_HIST_TRIGGERS
5596 " hist trigger\t- If set, event hits are aggregated into a hash table\n"
5597 "\t Format: hist:keys=<field1[,field2,...]>\n"
5598 "\t [:<var1>=<field|var_ref|numeric_literal>[,<var2>=...]]\n"
5599 "\t [:values=<field1[,field2,...]>]\n"
5600 "\t [:sort=<field1[,field2,...]>]\n"
5601 "\t [:size=#entries]\n"
5602 "\t [:pause][:continue][:clear]\n"
5603 "\t [:name=histname1]\n"
5604 "\t [:nohitcount]\n"
5605 "\t [:<handler>.<action>]\n"
5606 "\t [if <filter>]\n\n"
5607 "\t Note, special fields can be used as well:\n"
5608 "\t common_timestamp - to record current timestamp\n"
5609 "\t common_cpu - to record the CPU the event happened on\n"
5610 "\n"
5611 "\t A hist trigger variable can be:\n"
5612 "\t - a reference to a field e.g. x=current_timestamp,\n"
5613 "\t - a reference to another variable e.g. y=$x,\n"
5614 "\t - a numeric literal: e.g. ms_per_sec=1000,\n"
5615 "\t - an arithmetic expression: e.g. time_secs=current_timestamp/1000\n"
5616 "\n"
5617 "\t hist trigger arithmetic expressions support addition(+), subtraction(-),\n"
5618 "\t multiplication(*) and division(/) operators. An operand can be either a\n"
5619 "\t variable reference, field or numeric literal.\n"
5620 "\n"
5621 "\t When a matching event is hit, an entry is added to a hash\n"
5622 "\t table using the key(s) and value(s) named, and the value of a\n"
5623 "\t sum called 'hitcount' is incremented. Keys and values\n"
5624 "\t correspond to fields in the event's format description. Keys\n"
5625 "\t can be any field, or the special string 'common_stacktrace'.\n"
5626 "\t Compound keys consisting of up to two fields can be specified\n"
5627 "\t by the 'keys' keyword. Values must correspond to numeric\n"
5628 "\t fields. Sort keys consisting of up to two fields can be\n"
5629 "\t specified using the 'sort' keyword. The sort direction can\n"
5630 "\t be modified by appending '.descending' or '.ascending' to a\n"
5631 "\t sort field. The 'size' parameter can be used to specify more\n"
5632 "\t or fewer than the default 2048 entries for the hashtable size.\n"
5633 "\t If a hist trigger is given a name using the 'name' parameter,\n"
5634 "\t its histogram data will be shared with other triggers of the\n"
5635 "\t same name, and trigger hits will update this common data.\n\n"
5636 "\t Reading the 'hist' file for the event will dump the hash\n"
5637 "\t table in its entirety to stdout. If there are multiple hist\n"
5638 "\t triggers attached to an event, there will be a table for each\n"
5639 "\t trigger in the output. The table displayed for a named\n"
5640 "\t trigger will be the same as any other instance having the\n"
5641 "\t same name. The default format used to display a given field\n"
5642 "\t can be modified by appending any of the following modifiers\n"
5643 "\t to the field name, as applicable:\n\n"
5644 "\t .hex display a number as a hex value\n"
5645 "\t .sym display an address as a symbol\n"
5646 "\t .sym-offset display an address as a symbol and offset\n"
5647 "\t .execname display a common_pid as a program name\n"
5648 "\t .syscall display a syscall id as a syscall name\n"
5649 "\t .log2 display log2 value rather than raw number\n"
5650 "\t .buckets=size display values in groups of size rather than raw number\n"
5651 "\t .usecs display a common_timestamp in microseconds\n"
5652 "\t .percent display a number of percentage value\n"
5653 "\t .graph display a bar-graph of a value\n\n"
5654 "\t The 'pause' parameter can be used to pause an existing hist\n"
5655 "\t trigger or to start a hist trigger but not log any events\n"
5656 "\t until told to do so. 'continue' can be used to start or\n"
5657 "\t restart a paused hist trigger.\n\n"
5658 "\t The 'clear' parameter will clear the contents of a running\n"
5659 "\t hist trigger and leave its current paused/active state\n"
5660 "\t unchanged.\n\n"
5661 "\t The 'nohitcount' (or NOHC) parameter will suppress display of\n"
5662 "\t raw hitcount in the histogram.\n\n"
5663 "\t The enable_hist and disable_hist triggers can be used to\n"
5664 "\t have one event conditionally start and stop another event's\n"
5665 "\t already-attached hist trigger. The syntax is analogous to\n"
5666 "\t the enable_event and disable_event triggers.\n\n"
5667 "\t Hist trigger handlers and actions are executed whenever a\n"
5668 "\t a histogram entry is added or updated. They take the form:\n\n"
5669 "\t <handler>.<action>\n\n"
5670 "\t The available handlers are:\n\n"
5671 "\t onmatch(matching.event) - invoke on addition or update\n"
5672 "\t onmax(var) - invoke if var exceeds current max\n"
5673 "\t onchange(var) - invoke action if var changes\n\n"
5674 "\t The available actions are:\n\n"
5675 "\t trace(<synthetic_event>,param list) - generate synthetic event\n"
5676 "\t save(field,...) - save current event fields\n"
5677#ifdef CONFIG_TRACER_SNAPSHOT
5678 "\t snapshot() - snapshot the trace buffer\n\n"
5679#endif
5680#ifdef CONFIG_SYNTH_EVENTS
5681 " events/synthetic_events\t- Create/append/remove/show synthetic events\n"
5682 "\t Write into this file to define/undefine new synthetic events.\n"
5683 "\t example: echo 'myevent u64 lat; char name[]; long[] stack' >> synthetic_events\n"
5684#endif
5685#endif
5686;
5687
5688static ssize_t
5689tracing_readme_read(struct file *filp, char __user *ubuf,
5690 size_t cnt, loff_t *ppos)
5691{
5692 return simple_read_from_buffer(ubuf, cnt, ppos,
5693 readme_msg, strlen(readme_msg));
5694}
5695
5696static const struct file_operations tracing_readme_fops = {
5697 .open = tracing_open_generic,
5698 .read = tracing_readme_read,
5699 .llseek = generic_file_llseek,
5700};
5701
5702#ifdef CONFIG_TRACE_EVAL_MAP_FILE
5703static union trace_eval_map_item *
5704update_eval_map(union trace_eval_map_item *ptr)
5705{
5706 if (!ptr->map.eval_string) {
5707 if (ptr->tail.next) {
5708 ptr = ptr->tail.next;
5709 /* Set ptr to the next real item (skip head) */
5710 ptr++;
5711 } else
5712 return NULL;
5713 }
5714 return ptr;
5715}
5716
5717static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
5718{
5719 union trace_eval_map_item *ptr = v;
5720
5721 /*
5722 * Paranoid! If ptr points to end, we don't want to increment past it.
5723 * This really should never happen.
5724 */
5725 (*pos)++;
5726 ptr = update_eval_map(ptr);
5727 if (WARN_ON_ONCE(!ptr))
5728 return NULL;
5729
5730 ptr++;
5731 ptr = update_eval_map(ptr);
5732
5733 return ptr;
5734}
5735
5736static void *eval_map_start(struct seq_file *m, loff_t *pos)
5737{
5738 union trace_eval_map_item *v;
5739 loff_t l = 0;
5740
5741 mutex_lock(&trace_eval_mutex);
5742
5743 v = trace_eval_maps;
5744 if (v)
5745 v++;
5746
5747 while (v && l < *pos) {
5748 v = eval_map_next(m, v, &l);
5749 }
5750
5751 return v;
5752}
5753
5754static void eval_map_stop(struct seq_file *m, void *v)
5755{
5756 mutex_unlock(&trace_eval_mutex);
5757}
5758
5759static int eval_map_show(struct seq_file *m, void *v)
5760{
5761 union trace_eval_map_item *ptr = v;
5762
5763 seq_printf(m, "%s %ld (%s)\n",
5764 ptr->map.eval_string, ptr->map.eval_value,
5765 ptr->map.system);
5766
5767 return 0;
5768}
5769
5770static const struct seq_operations tracing_eval_map_seq_ops = {
5771 .start = eval_map_start,
5772 .next = eval_map_next,
5773 .stop = eval_map_stop,
5774 .show = eval_map_show,
5775};
5776
5777static int tracing_eval_map_open(struct inode *inode, struct file *filp)
5778{
5779 int ret;
5780
5781 ret = tracing_check_open_get_tr(NULL);
5782 if (ret)
5783 return ret;
5784
5785 return seq_open(filp, &tracing_eval_map_seq_ops);
5786}
5787
5788static const struct file_operations tracing_eval_map_fops = {
5789 .open = tracing_eval_map_open,
5790 .read = seq_read,
5791 .llseek = seq_lseek,
5792 .release = seq_release,
5793};
5794
5795static inline union trace_eval_map_item *
5796trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
5797{
5798 /* Return tail of array given the head */
5799 return ptr + ptr->head.length + 1;
5800}
5801
5802static void
5803trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
5804 int len)
5805{
5806 struct trace_eval_map **stop;
5807 struct trace_eval_map **map;
5808 union trace_eval_map_item *map_array;
5809 union trace_eval_map_item *ptr;
5810
5811 stop = start + len;
5812
5813 /*
5814 * The trace_eval_maps contains the map plus a head and tail item,
5815 * where the head holds the module and length of array, and the
5816 * tail holds a pointer to the next list.
5817 */
5818 map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
5819 if (!map_array) {
5820 pr_warn("Unable to allocate trace eval mapping\n");
5821 return;
5822 }
5823
5824 mutex_lock(&trace_eval_mutex);
5825
5826 if (!trace_eval_maps)
5827 trace_eval_maps = map_array;
5828 else {
5829 ptr = trace_eval_maps;
5830 for (;;) {
5831 ptr = trace_eval_jmp_to_tail(ptr);
5832 if (!ptr->tail.next)
5833 break;
5834 ptr = ptr->tail.next;
5835
5836 }
5837 ptr->tail.next = map_array;
5838 }
5839 map_array->head.mod = mod;
5840 map_array->head.length = len;
5841 map_array++;
5842
5843 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
5844 map_array->map = **map;
5845 map_array++;
5846 }
5847 memset(map_array, 0, sizeof(*map_array));
5848
5849 mutex_unlock(&trace_eval_mutex);
5850}
5851
5852static void trace_create_eval_file(struct dentry *d_tracer)
5853{
5854 trace_create_file("eval_map", TRACE_MODE_READ, d_tracer,
5855 NULL, &tracing_eval_map_fops);
5856}
5857
5858#else /* CONFIG_TRACE_EVAL_MAP_FILE */
5859static inline void trace_create_eval_file(struct dentry *d_tracer) { }
5860static inline void trace_insert_eval_map_file(struct module *mod,
5861 struct trace_eval_map **start, int len) { }
5862#endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
5863
5864static void trace_insert_eval_map(struct module *mod,
5865 struct trace_eval_map **start, int len)
5866{
5867 struct trace_eval_map **map;
5868
5869 if (len <= 0)
5870 return;
5871
5872 map = start;
5873
5874 trace_event_eval_update(map, len);
5875
5876 trace_insert_eval_map_file(mod, start, len);
5877}
5878
5879static ssize_t
5880tracing_set_trace_read(struct file *filp, char __user *ubuf,
5881 size_t cnt, loff_t *ppos)
5882{
5883 struct trace_array *tr = filp->private_data;
5884 char buf[MAX_TRACER_SIZE+2];
5885 int r;
5886
5887 mutex_lock(&trace_types_lock);
5888 r = sprintf(buf, "%s\n", tr->current_trace->name);
5889 mutex_unlock(&trace_types_lock);
5890
5891 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5892}
5893
5894int tracer_init(struct tracer *t, struct trace_array *tr)
5895{
5896 tracing_reset_online_cpus(&tr->array_buffer);
5897 return t->init(tr);
5898}
5899
5900static void set_buffer_entries(struct array_buffer *buf, unsigned long val)
5901{
5902 int cpu;
5903
5904 for_each_tracing_cpu(cpu)
5905 per_cpu_ptr(buf->data, cpu)->entries = val;
5906}
5907
5908static void update_buffer_entries(struct array_buffer *buf, int cpu)
5909{
5910 if (cpu == RING_BUFFER_ALL_CPUS) {
5911 set_buffer_entries(buf, ring_buffer_size(buf->buffer, 0));
5912 } else {
5913 per_cpu_ptr(buf->data, cpu)->entries = ring_buffer_size(buf->buffer, cpu);
5914 }
5915}
5916
5917#ifdef CONFIG_TRACER_MAX_TRACE
5918/* resize @tr's buffer to the size of @size_tr's entries */
5919static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
5920 struct array_buffer *size_buf, int cpu_id)
5921{
5922 int cpu, ret = 0;
5923
5924 if (cpu_id == RING_BUFFER_ALL_CPUS) {
5925 for_each_tracing_cpu(cpu) {
5926 ret = ring_buffer_resize(trace_buf->buffer,
5927 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
5928 if (ret < 0)
5929 break;
5930 per_cpu_ptr(trace_buf->data, cpu)->entries =
5931 per_cpu_ptr(size_buf->data, cpu)->entries;
5932 }
5933 } else {
5934 ret = ring_buffer_resize(trace_buf->buffer,
5935 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
5936 if (ret == 0)
5937 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
5938 per_cpu_ptr(size_buf->data, cpu_id)->entries;
5939 }
5940
5941 return ret;
5942}
5943#endif /* CONFIG_TRACER_MAX_TRACE */
5944
5945static int __tracing_resize_ring_buffer(struct trace_array *tr,
5946 unsigned long size, int cpu)
5947{
5948 int ret;
5949
5950 /*
5951 * If kernel or user changes the size of the ring buffer
5952 * we use the size that was given, and we can forget about
5953 * expanding it later.
5954 */
5955 trace_set_ring_buffer_expanded(tr);
5956
5957 /* May be called before buffers are initialized */
5958 if (!tr->array_buffer.buffer)
5959 return 0;
5960
5961 /* Do not allow tracing while resizing ring buffer */
5962 tracing_stop_tr(tr);
5963
5964 ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu);
5965 if (ret < 0)
5966 goto out_start;
5967
5968#ifdef CONFIG_TRACER_MAX_TRACE
5969 if (!tr->allocated_snapshot)
5970 goto out;
5971
5972 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
5973 if (ret < 0) {
5974 int r = resize_buffer_duplicate_size(&tr->array_buffer,
5975 &tr->array_buffer, cpu);
5976 if (r < 0) {
5977 /*
5978 * AARGH! We are left with different
5979 * size max buffer!!!!
5980 * The max buffer is our "snapshot" buffer.
5981 * When a tracer needs a snapshot (one of the
5982 * latency tracers), it swaps the max buffer
5983 * with the saved snap shot. We succeeded to
5984 * update the size of the main buffer, but failed to
5985 * update the size of the max buffer. But when we tried
5986 * to reset the main buffer to the original size, we
5987 * failed there too. This is very unlikely to
5988 * happen, but if it does, warn and kill all
5989 * tracing.
5990 */
5991 WARN_ON(1);
5992 tracing_disabled = 1;
5993 }
5994 goto out_start;
5995 }
5996
5997 update_buffer_entries(&tr->max_buffer, cpu);
5998
5999 out:
6000#endif /* CONFIG_TRACER_MAX_TRACE */
6001
6002 update_buffer_entries(&tr->array_buffer, cpu);
6003 out_start:
6004 tracing_start_tr(tr);
6005 return ret;
6006}
6007
6008ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
6009 unsigned long size, int cpu_id)
6010{
6011 int ret;
6012
6013 mutex_lock(&trace_types_lock);
6014
6015 if (cpu_id != RING_BUFFER_ALL_CPUS) {
6016 /* make sure, this cpu is enabled in the mask */
6017 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
6018 ret = -EINVAL;
6019 goto out;
6020 }
6021 }
6022
6023 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
6024 if (ret < 0)
6025 ret = -ENOMEM;
6026
6027out:
6028 mutex_unlock(&trace_types_lock);
6029
6030 return ret;
6031}
6032
6033
6034/**
6035 * tracing_update_buffers - used by tracing facility to expand ring buffers
6036 * @tr: The tracing instance
6037 *
6038 * To save on memory when the tracing is never used on a system with it
6039 * configured in. The ring buffers are set to a minimum size. But once
6040 * a user starts to use the tracing facility, then they need to grow
6041 * to their default size.
6042 *
6043 * This function is to be called when a tracer is about to be used.
6044 */
6045int tracing_update_buffers(struct trace_array *tr)
6046{
6047 int ret = 0;
6048
6049 mutex_lock(&trace_types_lock);
6050 if (!tr->ring_buffer_expanded)
6051 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6052 RING_BUFFER_ALL_CPUS);
6053 mutex_unlock(&trace_types_lock);
6054
6055 return ret;
6056}
6057
6058struct trace_option_dentry;
6059
6060static void
6061create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
6062
6063/*
6064 * Used to clear out the tracer before deletion of an instance.
6065 * Must have trace_types_lock held.
6066 */
6067static void tracing_set_nop(struct trace_array *tr)
6068{
6069 if (tr->current_trace == &nop_trace)
6070 return;
6071
6072 tr->current_trace->enabled--;
6073
6074 if (tr->current_trace->reset)
6075 tr->current_trace->reset(tr);
6076
6077 tr->current_trace = &nop_trace;
6078}
6079
6080static bool tracer_options_updated;
6081
6082static void add_tracer_options(struct trace_array *tr, struct tracer *t)
6083{
6084 /* Only enable if the directory has been created already. */
6085 if (!tr->dir)
6086 return;
6087
6088 /* Only create trace option files after update_tracer_options finish */
6089 if (!tracer_options_updated)
6090 return;
6091
6092 create_trace_option_files(tr, t);
6093}
6094
6095int tracing_set_tracer(struct trace_array *tr, const char *buf)
6096{
6097 struct tracer *t;
6098#ifdef CONFIG_TRACER_MAX_TRACE
6099 bool had_max_tr;
6100#endif
6101 int ret = 0;
6102
6103 mutex_lock(&trace_types_lock);
6104
6105 if (!tr->ring_buffer_expanded) {
6106 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6107 RING_BUFFER_ALL_CPUS);
6108 if (ret < 0)
6109 goto out;
6110 ret = 0;
6111 }
6112
6113 for (t = trace_types; t; t = t->next) {
6114 if (strcmp(t->name, buf) == 0)
6115 break;
6116 }
6117 if (!t) {
6118 ret = -EINVAL;
6119 goto out;
6120 }
6121 if (t == tr->current_trace)
6122 goto out;
6123
6124#ifdef CONFIG_TRACER_SNAPSHOT
6125 if (t->use_max_tr) {
6126 local_irq_disable();
6127 arch_spin_lock(&tr->max_lock);
6128 if (tr->cond_snapshot)
6129 ret = -EBUSY;
6130 arch_spin_unlock(&tr->max_lock);
6131 local_irq_enable();
6132 if (ret)
6133 goto out;
6134 }
6135#endif
6136 /* Some tracers won't work on kernel command line */
6137 if (system_state < SYSTEM_RUNNING && t->noboot) {
6138 pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
6139 t->name);
6140 goto out;
6141 }
6142
6143 /* Some tracers are only allowed for the top level buffer */
6144 if (!trace_ok_for_array(t, tr)) {
6145 ret = -EINVAL;
6146 goto out;
6147 }
6148
6149 /* If trace pipe files are being read, we can't change the tracer */
6150 if (tr->trace_ref) {
6151 ret = -EBUSY;
6152 goto out;
6153 }
6154
6155 trace_branch_disable();
6156
6157 tr->current_trace->enabled--;
6158
6159 if (tr->current_trace->reset)
6160 tr->current_trace->reset(tr);
6161
6162#ifdef CONFIG_TRACER_MAX_TRACE
6163 had_max_tr = tr->current_trace->use_max_tr;
6164
6165 /* Current trace needs to be nop_trace before synchronize_rcu */
6166 tr->current_trace = &nop_trace;
6167
6168 if (had_max_tr && !t->use_max_tr) {
6169 /*
6170 * We need to make sure that the update_max_tr sees that
6171 * current_trace changed to nop_trace to keep it from
6172 * swapping the buffers after we resize it.
6173 * The update_max_tr is called from interrupts disabled
6174 * so a synchronized_sched() is sufficient.
6175 */
6176 synchronize_rcu();
6177 free_snapshot(tr);
6178 tracing_disarm_snapshot(tr);
6179 }
6180
6181 if (!had_max_tr && t->use_max_tr) {
6182 ret = tracing_arm_snapshot_locked(tr);
6183 if (ret)
6184 goto out;
6185 }
6186#else
6187 tr->current_trace = &nop_trace;
6188#endif
6189
6190 if (t->init) {
6191 ret = tracer_init(t, tr);
6192 if (ret) {
6193#ifdef CONFIG_TRACER_MAX_TRACE
6194 if (t->use_max_tr)
6195 tracing_disarm_snapshot(tr);
6196#endif
6197 goto out;
6198 }
6199 }
6200
6201 tr->current_trace = t;
6202 tr->current_trace->enabled++;
6203 trace_branch_enable(tr);
6204 out:
6205 mutex_unlock(&trace_types_lock);
6206
6207 return ret;
6208}
6209
6210static ssize_t
6211tracing_set_trace_write(struct file *filp, const char __user *ubuf,
6212 size_t cnt, loff_t *ppos)
6213{
6214 struct trace_array *tr = filp->private_data;
6215 char buf[MAX_TRACER_SIZE+1];
6216 char *name;
6217 size_t ret;
6218 int err;
6219
6220 ret = cnt;
6221
6222 if (cnt > MAX_TRACER_SIZE)
6223 cnt = MAX_TRACER_SIZE;
6224
6225 if (copy_from_user(buf, ubuf, cnt))
6226 return -EFAULT;
6227
6228 buf[cnt] = 0;
6229
6230 name = strim(buf);
6231
6232 err = tracing_set_tracer(tr, name);
6233 if (err)
6234 return err;
6235
6236 *ppos += ret;
6237
6238 return ret;
6239}
6240
6241static ssize_t
6242tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
6243 size_t cnt, loff_t *ppos)
6244{
6245 char buf[64];
6246 int r;
6247
6248 r = snprintf(buf, sizeof(buf), "%ld\n",
6249 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
6250 if (r > sizeof(buf))
6251 r = sizeof(buf);
6252 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6253}
6254
6255static ssize_t
6256tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
6257 size_t cnt, loff_t *ppos)
6258{
6259 unsigned long val;
6260 int ret;
6261
6262 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6263 if (ret)
6264 return ret;
6265
6266 *ptr = val * 1000;
6267
6268 return cnt;
6269}
6270
6271static ssize_t
6272tracing_thresh_read(struct file *filp, char __user *ubuf,
6273 size_t cnt, loff_t *ppos)
6274{
6275 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
6276}
6277
6278static ssize_t
6279tracing_thresh_write(struct file *filp, const char __user *ubuf,
6280 size_t cnt, loff_t *ppos)
6281{
6282 struct trace_array *tr = filp->private_data;
6283 int ret;
6284
6285 mutex_lock(&trace_types_lock);
6286 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
6287 if (ret < 0)
6288 goto out;
6289
6290 if (tr->current_trace->update_thresh) {
6291 ret = tr->current_trace->update_thresh(tr);
6292 if (ret < 0)
6293 goto out;
6294 }
6295
6296 ret = cnt;
6297out:
6298 mutex_unlock(&trace_types_lock);
6299
6300 return ret;
6301}
6302
6303#ifdef CONFIG_TRACER_MAX_TRACE
6304
6305static ssize_t
6306tracing_max_lat_read(struct file *filp, char __user *ubuf,
6307 size_t cnt, loff_t *ppos)
6308{
6309 struct trace_array *tr = filp->private_data;
6310
6311 return tracing_nsecs_read(&tr->max_latency, ubuf, cnt, ppos);
6312}
6313
6314static ssize_t
6315tracing_max_lat_write(struct file *filp, const char __user *ubuf,
6316 size_t cnt, loff_t *ppos)
6317{
6318 struct trace_array *tr = filp->private_data;
6319
6320 return tracing_nsecs_write(&tr->max_latency, ubuf, cnt, ppos);
6321}
6322
6323#endif
6324
6325static int open_pipe_on_cpu(struct trace_array *tr, int cpu)
6326{
6327 if (cpu == RING_BUFFER_ALL_CPUS) {
6328 if (cpumask_empty(tr->pipe_cpumask)) {
6329 cpumask_setall(tr->pipe_cpumask);
6330 return 0;
6331 }
6332 } else if (!cpumask_test_cpu(cpu, tr->pipe_cpumask)) {
6333 cpumask_set_cpu(cpu, tr->pipe_cpumask);
6334 return 0;
6335 }
6336 return -EBUSY;
6337}
6338
6339static void close_pipe_on_cpu(struct trace_array *tr, int cpu)
6340{
6341 if (cpu == RING_BUFFER_ALL_CPUS) {
6342 WARN_ON(!cpumask_full(tr->pipe_cpumask));
6343 cpumask_clear(tr->pipe_cpumask);
6344 } else {
6345 WARN_ON(!cpumask_test_cpu(cpu, tr->pipe_cpumask));
6346 cpumask_clear_cpu(cpu, tr->pipe_cpumask);
6347 }
6348}
6349
6350static int tracing_open_pipe(struct inode *inode, struct file *filp)
6351{
6352 struct trace_array *tr = inode->i_private;
6353 struct trace_iterator *iter;
6354 int cpu;
6355 int ret;
6356
6357 ret = tracing_check_open_get_tr(tr);
6358 if (ret)
6359 return ret;
6360
6361 mutex_lock(&trace_types_lock);
6362 cpu = tracing_get_cpu(inode);
6363 ret = open_pipe_on_cpu(tr, cpu);
6364 if (ret)
6365 goto fail_pipe_on_cpu;
6366
6367 /* create a buffer to store the information to pass to userspace */
6368 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
6369 if (!iter) {
6370 ret = -ENOMEM;
6371 goto fail_alloc_iter;
6372 }
6373
6374 trace_seq_init(&iter->seq);
6375 iter->trace = tr->current_trace;
6376
6377 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
6378 ret = -ENOMEM;
6379 goto fail;
6380 }
6381
6382 /* trace pipe does not show start of buffer */
6383 cpumask_setall(iter->started);
6384
6385 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
6386 iter->iter_flags |= TRACE_FILE_LAT_FMT;
6387
6388 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
6389 if (trace_clocks[tr->clock_id].in_ns)
6390 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
6391
6392 iter->tr = tr;
6393 iter->array_buffer = &tr->array_buffer;
6394 iter->cpu_file = cpu;
6395 mutex_init(&iter->mutex);
6396 filp->private_data = iter;
6397
6398 if (iter->trace->pipe_open)
6399 iter->trace->pipe_open(iter);
6400
6401 nonseekable_open(inode, filp);
6402
6403 tr->trace_ref++;
6404
6405 mutex_unlock(&trace_types_lock);
6406 return ret;
6407
6408fail:
6409 kfree(iter);
6410fail_alloc_iter:
6411 close_pipe_on_cpu(tr, cpu);
6412fail_pipe_on_cpu:
6413 __trace_array_put(tr);
6414 mutex_unlock(&trace_types_lock);
6415 return ret;
6416}
6417
6418static int tracing_release_pipe(struct inode *inode, struct file *file)
6419{
6420 struct trace_iterator *iter = file->private_data;
6421 struct trace_array *tr = inode->i_private;
6422
6423 mutex_lock(&trace_types_lock);
6424
6425 tr->trace_ref--;
6426
6427 if (iter->trace->pipe_close)
6428 iter->trace->pipe_close(iter);
6429 close_pipe_on_cpu(tr, iter->cpu_file);
6430 mutex_unlock(&trace_types_lock);
6431
6432 free_trace_iter_content(iter);
6433 kfree(iter);
6434
6435 trace_array_put(tr);
6436
6437 return 0;
6438}
6439
6440static __poll_t
6441trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
6442{
6443 struct trace_array *tr = iter->tr;
6444
6445 /* Iterators are static, they should be filled or empty */
6446 if (trace_buffer_iter(iter, iter->cpu_file))
6447 return EPOLLIN | EPOLLRDNORM;
6448
6449 if (tr->trace_flags & TRACE_ITER_BLOCK)
6450 /*
6451 * Always select as readable when in blocking mode
6452 */
6453 return EPOLLIN | EPOLLRDNORM;
6454 else
6455 return ring_buffer_poll_wait(iter->array_buffer->buffer, iter->cpu_file,
6456 filp, poll_table, iter->tr->buffer_percent);
6457}
6458
6459static __poll_t
6460tracing_poll_pipe(struct file *filp, poll_table *poll_table)
6461{
6462 struct trace_iterator *iter = filp->private_data;
6463
6464 return trace_poll(iter, filp, poll_table);
6465}
6466
6467/* Must be called with iter->mutex held. */
6468static int tracing_wait_pipe(struct file *filp)
6469{
6470 struct trace_iterator *iter = filp->private_data;
6471 int ret;
6472
6473 while (trace_empty(iter)) {
6474
6475 if ((filp->f_flags & O_NONBLOCK)) {
6476 return -EAGAIN;
6477 }
6478
6479 /*
6480 * We block until we read something and tracing is disabled.
6481 * We still block if tracing is disabled, but we have never
6482 * read anything. This allows a user to cat this file, and
6483 * then enable tracing. But after we have read something,
6484 * we give an EOF when tracing is again disabled.
6485 *
6486 * iter->pos will be 0 if we haven't read anything.
6487 */
6488 if (!tracer_tracing_is_on(iter->tr) && iter->pos)
6489 break;
6490
6491 mutex_unlock(&iter->mutex);
6492
6493 ret = wait_on_pipe(iter, 0);
6494
6495 mutex_lock(&iter->mutex);
6496
6497 if (ret)
6498 return ret;
6499 }
6500
6501 return 1;
6502}
6503
6504/*
6505 * Consumer reader.
6506 */
6507static ssize_t
6508tracing_read_pipe(struct file *filp, char __user *ubuf,
6509 size_t cnt, loff_t *ppos)
6510{
6511 struct trace_iterator *iter = filp->private_data;
6512 ssize_t sret;
6513
6514 /*
6515 * Avoid more than one consumer on a single file descriptor
6516 * This is just a matter of traces coherency, the ring buffer itself
6517 * is protected.
6518 */
6519 mutex_lock(&iter->mutex);
6520
6521 /* return any leftover data */
6522 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6523 if (sret != -EBUSY)
6524 goto out;
6525
6526 trace_seq_init(&iter->seq);
6527
6528 if (iter->trace->read) {
6529 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
6530 if (sret)
6531 goto out;
6532 }
6533
6534waitagain:
6535 sret = tracing_wait_pipe(filp);
6536 if (sret <= 0)
6537 goto out;
6538
6539 /* stop when tracing is finished */
6540 if (trace_empty(iter)) {
6541 sret = 0;
6542 goto out;
6543 }
6544
6545 if (cnt >= TRACE_SEQ_BUFFER_SIZE)
6546 cnt = TRACE_SEQ_BUFFER_SIZE - 1;
6547
6548 /* reset all but tr, trace, and overruns */
6549 trace_iterator_reset(iter);
6550 cpumask_clear(iter->started);
6551 trace_seq_init(&iter->seq);
6552
6553 trace_event_read_lock();
6554 trace_access_lock(iter->cpu_file);
6555 while (trace_find_next_entry_inc(iter) != NULL) {
6556 enum print_line_t ret;
6557 int save_len = iter->seq.seq.len;
6558
6559 ret = print_trace_line(iter);
6560 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6561 /*
6562 * If one print_trace_line() fills entire trace_seq in one shot,
6563 * trace_seq_to_user() will returns -EBUSY because save_len == 0,
6564 * In this case, we need to consume it, otherwise, loop will peek
6565 * this event next time, resulting in an infinite loop.
6566 */
6567 if (save_len == 0) {
6568 iter->seq.full = 0;
6569 trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
6570 trace_consume(iter);
6571 break;
6572 }
6573
6574 /* In other cases, don't print partial lines */
6575 iter->seq.seq.len = save_len;
6576 break;
6577 }
6578 if (ret != TRACE_TYPE_NO_CONSUME)
6579 trace_consume(iter);
6580
6581 if (trace_seq_used(&iter->seq) >= cnt)
6582 break;
6583
6584 /*
6585 * Setting the full flag means we reached the trace_seq buffer
6586 * size and we should leave by partial output condition above.
6587 * One of the trace_seq_* functions is not used properly.
6588 */
6589 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
6590 iter->ent->type);
6591 }
6592 trace_access_unlock(iter->cpu_file);
6593 trace_event_read_unlock();
6594
6595 /* Now copy what we have to the user */
6596 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6597 if (iter->seq.readpos >= trace_seq_used(&iter->seq))
6598 trace_seq_init(&iter->seq);
6599
6600 /*
6601 * If there was nothing to send to user, in spite of consuming trace
6602 * entries, go back to wait for more entries.
6603 */
6604 if (sret == -EBUSY)
6605 goto waitagain;
6606
6607out:
6608 mutex_unlock(&iter->mutex);
6609
6610 return sret;
6611}
6612
6613static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
6614 unsigned int idx)
6615{
6616 __free_page(spd->pages[idx]);
6617}
6618
6619static size_t
6620tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
6621{
6622 size_t count;
6623 int save_len;
6624 int ret;
6625
6626 /* Seq buffer is page-sized, exactly what we need. */
6627 for (;;) {
6628 save_len = iter->seq.seq.len;
6629 ret = print_trace_line(iter);
6630
6631 if (trace_seq_has_overflowed(&iter->seq)) {
6632 iter->seq.seq.len = save_len;
6633 break;
6634 }
6635
6636 /*
6637 * This should not be hit, because it should only
6638 * be set if the iter->seq overflowed. But check it
6639 * anyway to be safe.
6640 */
6641 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6642 iter->seq.seq.len = save_len;
6643 break;
6644 }
6645
6646 count = trace_seq_used(&iter->seq) - save_len;
6647 if (rem < count) {
6648 rem = 0;
6649 iter->seq.seq.len = save_len;
6650 break;
6651 }
6652
6653 if (ret != TRACE_TYPE_NO_CONSUME)
6654 trace_consume(iter);
6655 rem -= count;
6656 if (!trace_find_next_entry_inc(iter)) {
6657 rem = 0;
6658 iter->ent = NULL;
6659 break;
6660 }
6661 }
6662
6663 return rem;
6664}
6665
6666static ssize_t tracing_splice_read_pipe(struct file *filp,
6667 loff_t *ppos,
6668 struct pipe_inode_info *pipe,
6669 size_t len,
6670 unsigned int flags)
6671{
6672 struct page *pages_def[PIPE_DEF_BUFFERS];
6673 struct partial_page partial_def[PIPE_DEF_BUFFERS];
6674 struct trace_iterator *iter = filp->private_data;
6675 struct splice_pipe_desc spd = {
6676 .pages = pages_def,
6677 .partial = partial_def,
6678 .nr_pages = 0, /* This gets updated below. */
6679 .nr_pages_max = PIPE_DEF_BUFFERS,
6680 .ops = &default_pipe_buf_ops,
6681 .spd_release = tracing_spd_release_pipe,
6682 };
6683 ssize_t ret;
6684 size_t rem;
6685 unsigned int i;
6686
6687 if (splice_grow_spd(pipe, &spd))
6688 return -ENOMEM;
6689
6690 mutex_lock(&iter->mutex);
6691
6692 if (iter->trace->splice_read) {
6693 ret = iter->trace->splice_read(iter, filp,
6694 ppos, pipe, len, flags);
6695 if (ret)
6696 goto out_err;
6697 }
6698
6699 ret = tracing_wait_pipe(filp);
6700 if (ret <= 0)
6701 goto out_err;
6702
6703 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
6704 ret = -EFAULT;
6705 goto out_err;
6706 }
6707
6708 trace_event_read_lock();
6709 trace_access_lock(iter->cpu_file);
6710
6711 /* Fill as many pages as possible. */
6712 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
6713 spd.pages[i] = alloc_page(GFP_KERNEL);
6714 if (!spd.pages[i])
6715 break;
6716
6717 rem = tracing_fill_pipe_page(rem, iter);
6718
6719 /* Copy the data into the page, so we can start over. */
6720 ret = trace_seq_to_buffer(&iter->seq,
6721 page_address(spd.pages[i]),
6722 trace_seq_used(&iter->seq));
6723 if (ret < 0) {
6724 __free_page(spd.pages[i]);
6725 break;
6726 }
6727 spd.partial[i].offset = 0;
6728 spd.partial[i].len = trace_seq_used(&iter->seq);
6729
6730 trace_seq_init(&iter->seq);
6731 }
6732
6733 trace_access_unlock(iter->cpu_file);
6734 trace_event_read_unlock();
6735 mutex_unlock(&iter->mutex);
6736
6737 spd.nr_pages = i;
6738
6739 if (i)
6740 ret = splice_to_pipe(pipe, &spd);
6741 else
6742 ret = 0;
6743out:
6744 splice_shrink_spd(&spd);
6745 return ret;
6746
6747out_err:
6748 mutex_unlock(&iter->mutex);
6749 goto out;
6750}
6751
6752static ssize_t
6753tracing_entries_read(struct file *filp, char __user *ubuf,
6754 size_t cnt, loff_t *ppos)
6755{
6756 struct inode *inode = file_inode(filp);
6757 struct trace_array *tr = inode->i_private;
6758 int cpu = tracing_get_cpu(inode);
6759 char buf[64];
6760 int r = 0;
6761 ssize_t ret;
6762
6763 mutex_lock(&trace_types_lock);
6764
6765 if (cpu == RING_BUFFER_ALL_CPUS) {
6766 int cpu, buf_size_same;
6767 unsigned long size;
6768
6769 size = 0;
6770 buf_size_same = 1;
6771 /* check if all cpu sizes are same */
6772 for_each_tracing_cpu(cpu) {
6773 /* fill in the size from first enabled cpu */
6774 if (size == 0)
6775 size = per_cpu_ptr(tr->array_buffer.data, cpu)->entries;
6776 if (size != per_cpu_ptr(tr->array_buffer.data, cpu)->entries) {
6777 buf_size_same = 0;
6778 break;
6779 }
6780 }
6781
6782 if (buf_size_same) {
6783 if (!tr->ring_buffer_expanded)
6784 r = sprintf(buf, "%lu (expanded: %lu)\n",
6785 size >> 10,
6786 trace_buf_size >> 10);
6787 else
6788 r = sprintf(buf, "%lu\n", size >> 10);
6789 } else
6790 r = sprintf(buf, "X\n");
6791 } else
6792 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10);
6793
6794 mutex_unlock(&trace_types_lock);
6795
6796 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6797 return ret;
6798}
6799
6800static ssize_t
6801tracing_entries_write(struct file *filp, const char __user *ubuf,
6802 size_t cnt, loff_t *ppos)
6803{
6804 struct inode *inode = file_inode(filp);
6805 struct trace_array *tr = inode->i_private;
6806 unsigned long val;
6807 int ret;
6808
6809 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6810 if (ret)
6811 return ret;
6812
6813 /* must have at least 1 entry */
6814 if (!val)
6815 return -EINVAL;
6816
6817 /* value is in KB */
6818 val <<= 10;
6819 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
6820 if (ret < 0)
6821 return ret;
6822
6823 *ppos += cnt;
6824
6825 return cnt;
6826}
6827
6828static ssize_t
6829tracing_total_entries_read(struct file *filp, char __user *ubuf,
6830 size_t cnt, loff_t *ppos)
6831{
6832 struct trace_array *tr = filp->private_data;
6833 char buf[64];
6834 int r, cpu;
6835 unsigned long size = 0, expanded_size = 0;
6836
6837 mutex_lock(&trace_types_lock);
6838 for_each_tracing_cpu(cpu) {
6839 size += per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10;
6840 if (!tr->ring_buffer_expanded)
6841 expanded_size += trace_buf_size >> 10;
6842 }
6843 if (tr->ring_buffer_expanded)
6844 r = sprintf(buf, "%lu\n", size);
6845 else
6846 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
6847 mutex_unlock(&trace_types_lock);
6848
6849 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6850}
6851
6852static ssize_t
6853tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
6854 size_t cnt, loff_t *ppos)
6855{
6856 /*
6857 * There is no need to read what the user has written, this function
6858 * is just to make sure that there is no error when "echo" is used
6859 */
6860
6861 *ppos += cnt;
6862
6863 return cnt;
6864}
6865
6866static int
6867tracing_free_buffer_release(struct inode *inode, struct file *filp)
6868{
6869 struct trace_array *tr = inode->i_private;
6870
6871 /* disable tracing ? */
6872 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
6873 tracer_tracing_off(tr);
6874 /* resize the ring buffer to 0 */
6875 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
6876
6877 trace_array_put(tr);
6878
6879 return 0;
6880}
6881
6882#define TRACE_MARKER_MAX_SIZE 4096
6883
6884static ssize_t
6885tracing_mark_write(struct file *filp, const char __user *ubuf,
6886 size_t cnt, loff_t *fpos)
6887{
6888 struct trace_array *tr = filp->private_data;
6889 struct ring_buffer_event *event;
6890 enum event_trigger_type tt = ETT_NONE;
6891 struct trace_buffer *buffer;
6892 struct print_entry *entry;
6893 int meta_size;
6894 ssize_t written;
6895 size_t size;
6896 int len;
6897
6898/* Used in tracing_mark_raw_write() as well */
6899#define FAULTED_STR "<faulted>"
6900#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */
6901
6902 if (tracing_disabled)
6903 return -EINVAL;
6904
6905 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
6906 return -EINVAL;
6907
6908 if ((ssize_t)cnt < 0)
6909 return -EINVAL;
6910
6911 if (cnt > TRACE_MARKER_MAX_SIZE)
6912 cnt = TRACE_MARKER_MAX_SIZE;
6913
6914 meta_size = sizeof(*entry) + 2; /* add '\0' and possible '\n' */
6915 again:
6916 size = cnt + meta_size;
6917
6918 /* If less than "<faulted>", then make sure we can still add that */
6919 if (cnt < FAULTED_SIZE)
6920 size += FAULTED_SIZE - cnt;
6921
6922 buffer = tr->array_buffer.buffer;
6923 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
6924 tracing_gen_ctx());
6925 if (unlikely(!event)) {
6926 /*
6927 * If the size was greater than what was allowed, then
6928 * make it smaller and try again.
6929 */
6930 if (size > ring_buffer_max_event_size(buffer)) {
6931 /* cnt < FAULTED size should never be bigger than max */
6932 if (WARN_ON_ONCE(cnt < FAULTED_SIZE))
6933 return -EBADF;
6934 cnt = ring_buffer_max_event_size(buffer) - meta_size;
6935 /* The above should only happen once */
6936 if (WARN_ON_ONCE(cnt + meta_size == size))
6937 return -EBADF;
6938 goto again;
6939 }
6940
6941 /* Ring buffer disabled, return as if not open for write */
6942 return -EBADF;
6943 }
6944
6945 entry = ring_buffer_event_data(event);
6946 entry->ip = _THIS_IP_;
6947
6948 len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
6949 if (len) {
6950 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
6951 cnt = FAULTED_SIZE;
6952 written = -EFAULT;
6953 } else
6954 written = cnt;
6955
6956 if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
6957 /* do not add \n before testing triggers, but add \0 */
6958 entry->buf[cnt] = '\0';
6959 tt = event_triggers_call(tr->trace_marker_file, buffer, entry, event);
6960 }
6961
6962 if (entry->buf[cnt - 1] != '\n') {
6963 entry->buf[cnt] = '\n';
6964 entry->buf[cnt + 1] = '\0';
6965 } else
6966 entry->buf[cnt] = '\0';
6967
6968 if (static_branch_unlikely(&trace_marker_exports_enabled))
6969 ftrace_exports(event, TRACE_EXPORT_MARKER);
6970 __buffer_unlock_commit(buffer, event);
6971
6972 if (tt)
6973 event_triggers_post_call(tr->trace_marker_file, tt);
6974
6975 return written;
6976}
6977
6978static ssize_t
6979tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
6980 size_t cnt, loff_t *fpos)
6981{
6982 struct trace_array *tr = filp->private_data;
6983 struct ring_buffer_event *event;
6984 struct trace_buffer *buffer;
6985 struct raw_data_entry *entry;
6986 ssize_t written;
6987 int size;
6988 int len;
6989
6990#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
6991
6992 if (tracing_disabled)
6993 return -EINVAL;
6994
6995 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
6996 return -EINVAL;
6997
6998 /* The marker must at least have a tag id */
6999 if (cnt < sizeof(unsigned int))
7000 return -EINVAL;
7001
7002 size = sizeof(*entry) + cnt;
7003 if (cnt < FAULT_SIZE_ID)
7004 size += FAULT_SIZE_ID - cnt;
7005
7006 buffer = tr->array_buffer.buffer;
7007
7008 if (size > ring_buffer_max_event_size(buffer))
7009 return -EINVAL;
7010
7011 event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
7012 tracing_gen_ctx());
7013 if (!event)
7014 /* Ring buffer disabled, return as if not open for write */
7015 return -EBADF;
7016
7017 entry = ring_buffer_event_data(event);
7018
7019 len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
7020 if (len) {
7021 entry->id = -1;
7022 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7023 written = -EFAULT;
7024 } else
7025 written = cnt;
7026
7027 __buffer_unlock_commit(buffer, event);
7028
7029 return written;
7030}
7031
7032static int tracing_clock_show(struct seq_file *m, void *v)
7033{
7034 struct trace_array *tr = m->private;
7035 int i;
7036
7037 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
7038 seq_printf(m,
7039 "%s%s%s%s", i ? " " : "",
7040 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
7041 i == tr->clock_id ? "]" : "");
7042 seq_putc(m, '\n');
7043
7044 return 0;
7045}
7046
7047int tracing_set_clock(struct trace_array *tr, const char *clockstr)
7048{
7049 int i;
7050
7051 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
7052 if (strcmp(trace_clocks[i].name, clockstr) == 0)
7053 break;
7054 }
7055 if (i == ARRAY_SIZE(trace_clocks))
7056 return -EINVAL;
7057
7058 mutex_lock(&trace_types_lock);
7059
7060 tr->clock_id = i;
7061
7062 ring_buffer_set_clock(tr->array_buffer.buffer, trace_clocks[i].func);
7063
7064 /*
7065 * New clock may not be consistent with the previous clock.
7066 * Reset the buffer so that it doesn't have incomparable timestamps.
7067 */
7068 tracing_reset_online_cpus(&tr->array_buffer);
7069
7070#ifdef CONFIG_TRACER_MAX_TRACE
7071 if (tr->max_buffer.buffer)
7072 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
7073 tracing_reset_online_cpus(&tr->max_buffer);
7074#endif
7075
7076 mutex_unlock(&trace_types_lock);
7077
7078 return 0;
7079}
7080
7081static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
7082 size_t cnt, loff_t *fpos)
7083{
7084 struct seq_file *m = filp->private_data;
7085 struct trace_array *tr = m->private;
7086 char buf[64];
7087 const char *clockstr;
7088 int ret;
7089
7090 if (cnt >= sizeof(buf))
7091 return -EINVAL;
7092
7093 if (copy_from_user(buf, ubuf, cnt))
7094 return -EFAULT;
7095
7096 buf[cnt] = 0;
7097
7098 clockstr = strstrip(buf);
7099
7100 ret = tracing_set_clock(tr, clockstr);
7101 if (ret)
7102 return ret;
7103
7104 *fpos += cnt;
7105
7106 return cnt;
7107}
7108
7109static int tracing_clock_open(struct inode *inode, struct file *file)
7110{
7111 struct trace_array *tr = inode->i_private;
7112 int ret;
7113
7114 ret = tracing_check_open_get_tr(tr);
7115 if (ret)
7116 return ret;
7117
7118 ret = single_open(file, tracing_clock_show, inode->i_private);
7119 if (ret < 0)
7120 trace_array_put(tr);
7121
7122 return ret;
7123}
7124
7125static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
7126{
7127 struct trace_array *tr = m->private;
7128
7129 mutex_lock(&trace_types_lock);
7130
7131 if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer))
7132 seq_puts(m, "delta [absolute]\n");
7133 else
7134 seq_puts(m, "[delta] absolute\n");
7135
7136 mutex_unlock(&trace_types_lock);
7137
7138 return 0;
7139}
7140
7141static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
7142{
7143 struct trace_array *tr = inode->i_private;
7144 int ret;
7145
7146 ret = tracing_check_open_get_tr(tr);
7147 if (ret)
7148 return ret;
7149
7150 ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
7151 if (ret < 0)
7152 trace_array_put(tr);
7153
7154 return ret;
7155}
7156
7157u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe)
7158{
7159 if (rbe == this_cpu_read(trace_buffered_event))
7160 return ring_buffer_time_stamp(buffer);
7161
7162 return ring_buffer_event_time_stamp(buffer, rbe);
7163}
7164
7165/*
7166 * Set or disable using the per CPU trace_buffer_event when possible.
7167 */
7168int tracing_set_filter_buffering(struct trace_array *tr, bool set)
7169{
7170 int ret = 0;
7171
7172 mutex_lock(&trace_types_lock);
7173
7174 if (set && tr->no_filter_buffering_ref++)
7175 goto out;
7176
7177 if (!set) {
7178 if (WARN_ON_ONCE(!tr->no_filter_buffering_ref)) {
7179 ret = -EINVAL;
7180 goto out;
7181 }
7182
7183 --tr->no_filter_buffering_ref;
7184 }
7185 out:
7186 mutex_unlock(&trace_types_lock);
7187
7188 return ret;
7189}
7190
7191struct ftrace_buffer_info {
7192 struct trace_iterator iter;
7193 void *spare;
7194 unsigned int spare_cpu;
7195 unsigned int spare_size;
7196 unsigned int read;
7197};
7198
7199#ifdef CONFIG_TRACER_SNAPSHOT
7200static int tracing_snapshot_open(struct inode *inode, struct file *file)
7201{
7202 struct trace_array *tr = inode->i_private;
7203 struct trace_iterator *iter;
7204 struct seq_file *m;
7205 int ret;
7206
7207 ret = tracing_check_open_get_tr(tr);
7208 if (ret)
7209 return ret;
7210
7211 if (file->f_mode & FMODE_READ) {
7212 iter = __tracing_open(inode, file, true);
7213 if (IS_ERR(iter))
7214 ret = PTR_ERR(iter);
7215 } else {
7216 /* Writes still need the seq_file to hold the private data */
7217 ret = -ENOMEM;
7218 m = kzalloc(sizeof(*m), GFP_KERNEL);
7219 if (!m)
7220 goto out;
7221 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
7222 if (!iter) {
7223 kfree(m);
7224 goto out;
7225 }
7226 ret = 0;
7227
7228 iter->tr = tr;
7229 iter->array_buffer = &tr->max_buffer;
7230 iter->cpu_file = tracing_get_cpu(inode);
7231 m->private = iter;
7232 file->private_data = m;
7233 }
7234out:
7235 if (ret < 0)
7236 trace_array_put(tr);
7237
7238 return ret;
7239}
7240
7241static void tracing_swap_cpu_buffer(void *tr)
7242{
7243 update_max_tr_single((struct trace_array *)tr, current, smp_processor_id());
7244}
7245
7246static ssize_t
7247tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
7248 loff_t *ppos)
7249{
7250 struct seq_file *m = filp->private_data;
7251 struct trace_iterator *iter = m->private;
7252 struct trace_array *tr = iter->tr;
7253 unsigned long val;
7254 int ret;
7255
7256 ret = tracing_update_buffers(tr);
7257 if (ret < 0)
7258 return ret;
7259
7260 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7261 if (ret)
7262 return ret;
7263
7264 mutex_lock(&trace_types_lock);
7265
7266 if (tr->current_trace->use_max_tr) {
7267 ret = -EBUSY;
7268 goto out;
7269 }
7270
7271 local_irq_disable();
7272 arch_spin_lock(&tr->max_lock);
7273 if (tr->cond_snapshot)
7274 ret = -EBUSY;
7275 arch_spin_unlock(&tr->max_lock);
7276 local_irq_enable();
7277 if (ret)
7278 goto out;
7279
7280 switch (val) {
7281 case 0:
7282 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7283 ret = -EINVAL;
7284 break;
7285 }
7286 if (tr->allocated_snapshot)
7287 free_snapshot(tr);
7288 break;
7289 case 1:
7290/* Only allow per-cpu swap if the ring buffer supports it */
7291#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
7292 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7293 ret = -EINVAL;
7294 break;
7295 }
7296#endif
7297 if (tr->allocated_snapshot)
7298 ret = resize_buffer_duplicate_size(&tr->max_buffer,
7299 &tr->array_buffer, iter->cpu_file);
7300
7301 ret = tracing_arm_snapshot_locked(tr);
7302 if (ret)
7303 break;
7304
7305 /* Now, we're going to swap */
7306 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
7307 local_irq_disable();
7308 update_max_tr(tr, current, smp_processor_id(), NULL);
7309 local_irq_enable();
7310 } else {
7311 smp_call_function_single(iter->cpu_file, tracing_swap_cpu_buffer,
7312 (void *)tr, 1);
7313 }
7314 tracing_disarm_snapshot(tr);
7315 break;
7316 default:
7317 if (tr->allocated_snapshot) {
7318 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
7319 tracing_reset_online_cpus(&tr->max_buffer);
7320 else
7321 tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
7322 }
7323 break;
7324 }
7325
7326 if (ret >= 0) {
7327 *ppos += cnt;
7328 ret = cnt;
7329 }
7330out:
7331 mutex_unlock(&trace_types_lock);
7332 return ret;
7333}
7334
7335static int tracing_snapshot_release(struct inode *inode, struct file *file)
7336{
7337 struct seq_file *m = file->private_data;
7338 int ret;
7339
7340 ret = tracing_release(inode, file);
7341
7342 if (file->f_mode & FMODE_READ)
7343 return ret;
7344
7345 /* If write only, the seq_file is just a stub */
7346 if (m)
7347 kfree(m->private);
7348 kfree(m);
7349
7350 return 0;
7351}
7352
7353static int tracing_buffers_open(struct inode *inode, struct file *filp);
7354static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
7355 size_t count, loff_t *ppos);
7356static int tracing_buffers_release(struct inode *inode, struct file *file);
7357static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
7358 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
7359
7360static int snapshot_raw_open(struct inode *inode, struct file *filp)
7361{
7362 struct ftrace_buffer_info *info;
7363 int ret;
7364
7365 /* The following checks for tracefs lockdown */
7366 ret = tracing_buffers_open(inode, filp);
7367 if (ret < 0)
7368 return ret;
7369
7370 info = filp->private_data;
7371
7372 if (info->iter.trace->use_max_tr) {
7373 tracing_buffers_release(inode, filp);
7374 return -EBUSY;
7375 }
7376
7377 info->iter.snapshot = true;
7378 info->iter.array_buffer = &info->iter.tr->max_buffer;
7379
7380 return ret;
7381}
7382
7383#endif /* CONFIG_TRACER_SNAPSHOT */
7384
7385
7386static const struct file_operations tracing_thresh_fops = {
7387 .open = tracing_open_generic,
7388 .read = tracing_thresh_read,
7389 .write = tracing_thresh_write,
7390 .llseek = generic_file_llseek,
7391};
7392
7393#ifdef CONFIG_TRACER_MAX_TRACE
7394static const struct file_operations tracing_max_lat_fops = {
7395 .open = tracing_open_generic_tr,
7396 .read = tracing_max_lat_read,
7397 .write = tracing_max_lat_write,
7398 .llseek = generic_file_llseek,
7399 .release = tracing_release_generic_tr,
7400};
7401#endif
7402
7403static const struct file_operations set_tracer_fops = {
7404 .open = tracing_open_generic_tr,
7405 .read = tracing_set_trace_read,
7406 .write = tracing_set_trace_write,
7407 .llseek = generic_file_llseek,
7408 .release = tracing_release_generic_tr,
7409};
7410
7411static const struct file_operations tracing_pipe_fops = {
7412 .open = tracing_open_pipe,
7413 .poll = tracing_poll_pipe,
7414 .read = tracing_read_pipe,
7415 .splice_read = tracing_splice_read_pipe,
7416 .release = tracing_release_pipe,
7417 .llseek = no_llseek,
7418};
7419
7420static const struct file_operations tracing_entries_fops = {
7421 .open = tracing_open_generic_tr,
7422 .read = tracing_entries_read,
7423 .write = tracing_entries_write,
7424 .llseek = generic_file_llseek,
7425 .release = tracing_release_generic_tr,
7426};
7427
7428static const struct file_operations tracing_total_entries_fops = {
7429 .open = tracing_open_generic_tr,
7430 .read = tracing_total_entries_read,
7431 .llseek = generic_file_llseek,
7432 .release = tracing_release_generic_tr,
7433};
7434
7435static const struct file_operations tracing_free_buffer_fops = {
7436 .open = tracing_open_generic_tr,
7437 .write = tracing_free_buffer_write,
7438 .release = tracing_free_buffer_release,
7439};
7440
7441static const struct file_operations tracing_mark_fops = {
7442 .open = tracing_mark_open,
7443 .write = tracing_mark_write,
7444 .release = tracing_release_generic_tr,
7445};
7446
7447static const struct file_operations tracing_mark_raw_fops = {
7448 .open = tracing_mark_open,
7449 .write = tracing_mark_raw_write,
7450 .release = tracing_release_generic_tr,
7451};
7452
7453static const struct file_operations trace_clock_fops = {
7454 .open = tracing_clock_open,
7455 .read = seq_read,
7456 .llseek = seq_lseek,
7457 .release = tracing_single_release_tr,
7458 .write = tracing_clock_write,
7459};
7460
7461static const struct file_operations trace_time_stamp_mode_fops = {
7462 .open = tracing_time_stamp_mode_open,
7463 .read = seq_read,
7464 .llseek = seq_lseek,
7465 .release = tracing_single_release_tr,
7466};
7467
7468#ifdef CONFIG_TRACER_SNAPSHOT
7469static const struct file_operations snapshot_fops = {
7470 .open = tracing_snapshot_open,
7471 .read = seq_read,
7472 .write = tracing_snapshot_write,
7473 .llseek = tracing_lseek,
7474 .release = tracing_snapshot_release,
7475};
7476
7477static const struct file_operations snapshot_raw_fops = {
7478 .open = snapshot_raw_open,
7479 .read = tracing_buffers_read,
7480 .release = tracing_buffers_release,
7481 .splice_read = tracing_buffers_splice_read,
7482 .llseek = no_llseek,
7483};
7484
7485#endif /* CONFIG_TRACER_SNAPSHOT */
7486
7487/*
7488 * trace_min_max_write - Write a u64 value to a trace_min_max_param struct
7489 * @filp: The active open file structure
7490 * @ubuf: The userspace provided buffer to read value into
7491 * @cnt: The maximum number of bytes to read
7492 * @ppos: The current "file" position
7493 *
7494 * This function implements the write interface for a struct trace_min_max_param.
7495 * The filp->private_data must point to a trace_min_max_param structure that
7496 * defines where to write the value, the min and the max acceptable values,
7497 * and a lock to protect the write.
7498 */
7499static ssize_t
7500trace_min_max_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos)
7501{
7502 struct trace_min_max_param *param = filp->private_data;
7503 u64 val;
7504 int err;
7505
7506 if (!param)
7507 return -EFAULT;
7508
7509 err = kstrtoull_from_user(ubuf, cnt, 10, &val);
7510 if (err)
7511 return err;
7512
7513 if (param->lock)
7514 mutex_lock(param->lock);
7515
7516 if (param->min && val < *param->min)
7517 err = -EINVAL;
7518
7519 if (param->max && val > *param->max)
7520 err = -EINVAL;
7521
7522 if (!err)
7523 *param->val = val;
7524
7525 if (param->lock)
7526 mutex_unlock(param->lock);
7527
7528 if (err)
7529 return err;
7530
7531 return cnt;
7532}
7533
7534/*
7535 * trace_min_max_read - Read a u64 value from a trace_min_max_param struct
7536 * @filp: The active open file structure
7537 * @ubuf: The userspace provided buffer to read value into
7538 * @cnt: The maximum number of bytes to read
7539 * @ppos: The current "file" position
7540 *
7541 * This function implements the read interface for a struct trace_min_max_param.
7542 * The filp->private_data must point to a trace_min_max_param struct with valid
7543 * data.
7544 */
7545static ssize_t
7546trace_min_max_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
7547{
7548 struct trace_min_max_param *param = filp->private_data;
7549 char buf[U64_STR_SIZE];
7550 int len;
7551 u64 val;
7552
7553 if (!param)
7554 return -EFAULT;
7555
7556 val = *param->val;
7557
7558 if (cnt > sizeof(buf))
7559 cnt = sizeof(buf);
7560
7561 len = snprintf(buf, sizeof(buf), "%llu\n", val);
7562
7563 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
7564}
7565
7566const struct file_operations trace_min_max_fops = {
7567 .open = tracing_open_generic,
7568 .read = trace_min_max_read,
7569 .write = trace_min_max_write,
7570};
7571
7572#define TRACING_LOG_ERRS_MAX 8
7573#define TRACING_LOG_LOC_MAX 128
7574
7575#define CMD_PREFIX " Command: "
7576
7577struct err_info {
7578 const char **errs; /* ptr to loc-specific array of err strings */
7579 u8 type; /* index into errs -> specific err string */
7580 u16 pos; /* caret position */
7581 u64 ts;
7582};
7583
7584struct tracing_log_err {
7585 struct list_head list;
7586 struct err_info info;
7587 char loc[TRACING_LOG_LOC_MAX]; /* err location */
7588 char *cmd; /* what caused err */
7589};
7590
7591static DEFINE_MUTEX(tracing_err_log_lock);
7592
7593static struct tracing_log_err *alloc_tracing_log_err(int len)
7594{
7595 struct tracing_log_err *err;
7596
7597 err = kzalloc(sizeof(*err), GFP_KERNEL);
7598 if (!err)
7599 return ERR_PTR(-ENOMEM);
7600
7601 err->cmd = kzalloc(len, GFP_KERNEL);
7602 if (!err->cmd) {
7603 kfree(err);
7604 return ERR_PTR(-ENOMEM);
7605 }
7606
7607 return err;
7608}
7609
7610static void free_tracing_log_err(struct tracing_log_err *err)
7611{
7612 kfree(err->cmd);
7613 kfree(err);
7614}
7615
7616static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr,
7617 int len)
7618{
7619 struct tracing_log_err *err;
7620 char *cmd;
7621
7622 if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
7623 err = alloc_tracing_log_err(len);
7624 if (PTR_ERR(err) != -ENOMEM)
7625 tr->n_err_log_entries++;
7626
7627 return err;
7628 }
7629 cmd = kzalloc(len, GFP_KERNEL);
7630 if (!cmd)
7631 return ERR_PTR(-ENOMEM);
7632 err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
7633 kfree(err->cmd);
7634 err->cmd = cmd;
7635 list_del(&err->list);
7636
7637 return err;
7638}
7639
7640/**
7641 * err_pos - find the position of a string within a command for error careting
7642 * @cmd: The tracing command that caused the error
7643 * @str: The string to position the caret at within @cmd
7644 *
7645 * Finds the position of the first occurrence of @str within @cmd. The
7646 * return value can be passed to tracing_log_err() for caret placement
7647 * within @cmd.
7648 *
7649 * Returns the index within @cmd of the first occurrence of @str or 0
7650 * if @str was not found.
7651 */
7652unsigned int err_pos(char *cmd, const char *str)
7653{
7654 char *found;
7655
7656 if (WARN_ON(!strlen(cmd)))
7657 return 0;
7658
7659 found = strstr(cmd, str);
7660 if (found)
7661 return found - cmd;
7662
7663 return 0;
7664}
7665
7666/**
7667 * tracing_log_err - write an error to the tracing error log
7668 * @tr: The associated trace array for the error (NULL for top level array)
7669 * @loc: A string describing where the error occurred
7670 * @cmd: The tracing command that caused the error
7671 * @errs: The array of loc-specific static error strings
7672 * @type: The index into errs[], which produces the specific static err string
7673 * @pos: The position the caret should be placed in the cmd
7674 *
7675 * Writes an error into tracing/error_log of the form:
7676 *
7677 * <loc>: error: <text>
7678 * Command: <cmd>
7679 * ^
7680 *
7681 * tracing/error_log is a small log file containing the last
7682 * TRACING_LOG_ERRS_MAX errors (8). Memory for errors isn't allocated
7683 * unless there has been a tracing error, and the error log can be
7684 * cleared and have its memory freed by writing the empty string in
7685 * truncation mode to it i.e. echo > tracing/error_log.
7686 *
7687 * NOTE: the @errs array along with the @type param are used to
7688 * produce a static error string - this string is not copied and saved
7689 * when the error is logged - only a pointer to it is saved. See
7690 * existing callers for examples of how static strings are typically
7691 * defined for use with tracing_log_err().
7692 */
7693void tracing_log_err(struct trace_array *tr,
7694 const char *loc, const char *cmd,
7695 const char **errs, u8 type, u16 pos)
7696{
7697 struct tracing_log_err *err;
7698 int len = 0;
7699
7700 if (!tr)
7701 tr = &global_trace;
7702
7703 len += sizeof(CMD_PREFIX) + 2 * sizeof("\n") + strlen(cmd) + 1;
7704
7705 mutex_lock(&tracing_err_log_lock);
7706 err = get_tracing_log_err(tr, len);
7707 if (PTR_ERR(err) == -ENOMEM) {
7708 mutex_unlock(&tracing_err_log_lock);
7709 return;
7710 }
7711
7712 snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
7713 snprintf(err->cmd, len, "\n" CMD_PREFIX "%s\n", cmd);
7714
7715 err->info.errs = errs;
7716 err->info.type = type;
7717 err->info.pos = pos;
7718 err->info.ts = local_clock();
7719
7720 list_add_tail(&err->list, &tr->err_log);
7721 mutex_unlock(&tracing_err_log_lock);
7722}
7723
7724static void clear_tracing_err_log(struct trace_array *tr)
7725{
7726 struct tracing_log_err *err, *next;
7727
7728 mutex_lock(&tracing_err_log_lock);
7729 list_for_each_entry_safe(err, next, &tr->err_log, list) {
7730 list_del(&err->list);
7731 free_tracing_log_err(err);
7732 }
7733
7734 tr->n_err_log_entries = 0;
7735 mutex_unlock(&tracing_err_log_lock);
7736}
7737
7738static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
7739{
7740 struct trace_array *tr = m->private;
7741
7742 mutex_lock(&tracing_err_log_lock);
7743
7744 return seq_list_start(&tr->err_log, *pos);
7745}
7746
7747static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos)
7748{
7749 struct trace_array *tr = m->private;
7750
7751 return seq_list_next(v, &tr->err_log, pos);
7752}
7753
7754static void tracing_err_log_seq_stop(struct seq_file *m, void *v)
7755{
7756 mutex_unlock(&tracing_err_log_lock);
7757}
7758
7759static void tracing_err_log_show_pos(struct seq_file *m, u16 pos)
7760{
7761 u16 i;
7762
7763 for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++)
7764 seq_putc(m, ' ');
7765 for (i = 0; i < pos; i++)
7766 seq_putc(m, ' ');
7767 seq_puts(m, "^\n");
7768}
7769
7770static int tracing_err_log_seq_show(struct seq_file *m, void *v)
7771{
7772 struct tracing_log_err *err = v;
7773
7774 if (err) {
7775 const char *err_text = err->info.errs[err->info.type];
7776 u64 sec = err->info.ts;
7777 u32 nsec;
7778
7779 nsec = do_div(sec, NSEC_PER_SEC);
7780 seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000,
7781 err->loc, err_text);
7782 seq_printf(m, "%s", err->cmd);
7783 tracing_err_log_show_pos(m, err->info.pos);
7784 }
7785
7786 return 0;
7787}
7788
7789static const struct seq_operations tracing_err_log_seq_ops = {
7790 .start = tracing_err_log_seq_start,
7791 .next = tracing_err_log_seq_next,
7792 .stop = tracing_err_log_seq_stop,
7793 .show = tracing_err_log_seq_show
7794};
7795
7796static int tracing_err_log_open(struct inode *inode, struct file *file)
7797{
7798 struct trace_array *tr = inode->i_private;
7799 int ret = 0;
7800
7801 ret = tracing_check_open_get_tr(tr);
7802 if (ret)
7803 return ret;
7804
7805 /* If this file was opened for write, then erase contents */
7806 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
7807 clear_tracing_err_log(tr);
7808
7809 if (file->f_mode & FMODE_READ) {
7810 ret = seq_open(file, &tracing_err_log_seq_ops);
7811 if (!ret) {
7812 struct seq_file *m = file->private_data;
7813 m->private = tr;
7814 } else {
7815 trace_array_put(tr);
7816 }
7817 }
7818 return ret;
7819}
7820
7821static ssize_t tracing_err_log_write(struct file *file,
7822 const char __user *buffer,
7823 size_t count, loff_t *ppos)
7824{
7825 return count;
7826}
7827
7828static int tracing_err_log_release(struct inode *inode, struct file *file)
7829{
7830 struct trace_array *tr = inode->i_private;
7831
7832 trace_array_put(tr);
7833
7834 if (file->f_mode & FMODE_READ)
7835 seq_release(inode, file);
7836
7837 return 0;
7838}
7839
7840static const struct file_operations tracing_err_log_fops = {
7841 .open = tracing_err_log_open,
7842 .write = tracing_err_log_write,
7843 .read = seq_read,
7844 .llseek = tracing_lseek,
7845 .release = tracing_err_log_release,
7846};
7847
7848static int tracing_buffers_open(struct inode *inode, struct file *filp)
7849{
7850 struct trace_array *tr = inode->i_private;
7851 struct ftrace_buffer_info *info;
7852 int ret;
7853
7854 ret = tracing_check_open_get_tr(tr);
7855 if (ret)
7856 return ret;
7857
7858 info = kvzalloc(sizeof(*info), GFP_KERNEL);
7859 if (!info) {
7860 trace_array_put(tr);
7861 return -ENOMEM;
7862 }
7863
7864 mutex_lock(&trace_types_lock);
7865
7866 info->iter.tr = tr;
7867 info->iter.cpu_file = tracing_get_cpu(inode);
7868 info->iter.trace = tr->current_trace;
7869 info->iter.array_buffer = &tr->array_buffer;
7870 info->spare = NULL;
7871 /* Force reading ring buffer for first read */
7872 info->read = (unsigned int)-1;
7873
7874 filp->private_data = info;
7875
7876 tr->trace_ref++;
7877
7878 mutex_unlock(&trace_types_lock);
7879
7880 ret = nonseekable_open(inode, filp);
7881 if (ret < 0)
7882 trace_array_put(tr);
7883
7884 return ret;
7885}
7886
7887static __poll_t
7888tracing_buffers_poll(struct file *filp, poll_table *poll_table)
7889{
7890 struct ftrace_buffer_info *info = filp->private_data;
7891 struct trace_iterator *iter = &info->iter;
7892
7893 return trace_poll(iter, filp, poll_table);
7894}
7895
7896static ssize_t
7897tracing_buffers_read(struct file *filp, char __user *ubuf,
7898 size_t count, loff_t *ppos)
7899{
7900 struct ftrace_buffer_info *info = filp->private_data;
7901 struct trace_iterator *iter = &info->iter;
7902 void *trace_data;
7903 int page_size;
7904 ssize_t ret = 0;
7905 ssize_t size;
7906
7907 if (!count)
7908 return 0;
7909
7910#ifdef CONFIG_TRACER_MAX_TRACE
7911 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
7912 return -EBUSY;
7913#endif
7914
7915 page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
7916
7917 /* Make sure the spare matches the current sub buffer size */
7918 if (info->spare) {
7919 if (page_size != info->spare_size) {
7920 ring_buffer_free_read_page(iter->array_buffer->buffer,
7921 info->spare_cpu, info->spare);
7922 info->spare = NULL;
7923 }
7924 }
7925
7926 if (!info->spare) {
7927 info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer,
7928 iter->cpu_file);
7929 if (IS_ERR(info->spare)) {
7930 ret = PTR_ERR(info->spare);
7931 info->spare = NULL;
7932 } else {
7933 info->spare_cpu = iter->cpu_file;
7934 info->spare_size = page_size;
7935 }
7936 }
7937 if (!info->spare)
7938 return ret;
7939
7940 /* Do we have previous read data to read? */
7941 if (info->read < page_size)
7942 goto read;
7943
7944 again:
7945 trace_access_lock(iter->cpu_file);
7946 ret = ring_buffer_read_page(iter->array_buffer->buffer,
7947 info->spare,
7948 count,
7949 iter->cpu_file, 0);
7950 trace_access_unlock(iter->cpu_file);
7951
7952 if (ret < 0) {
7953 if (trace_empty(iter)) {
7954 if ((filp->f_flags & O_NONBLOCK))
7955 return -EAGAIN;
7956
7957 ret = wait_on_pipe(iter, 0);
7958 if (ret)
7959 return ret;
7960
7961 goto again;
7962 }
7963 return 0;
7964 }
7965
7966 info->read = 0;
7967 read:
7968 size = page_size - info->read;
7969 if (size > count)
7970 size = count;
7971 trace_data = ring_buffer_read_page_data(info->spare);
7972 ret = copy_to_user(ubuf, trace_data + info->read, size);
7973 if (ret == size)
7974 return -EFAULT;
7975
7976 size -= ret;
7977
7978 *ppos += size;
7979 info->read += size;
7980
7981 return size;
7982}
7983
7984static int tracing_buffers_flush(struct file *file, fl_owner_t id)
7985{
7986 struct ftrace_buffer_info *info = file->private_data;
7987 struct trace_iterator *iter = &info->iter;
7988
7989 iter->closed = true;
7990 /* Make sure the waiters see the new wait_index */
7991 (void)atomic_fetch_inc_release(&iter->wait_index);
7992
7993 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
7994
7995 return 0;
7996}
7997
7998static int tracing_buffers_release(struct inode *inode, struct file *file)
7999{
8000 struct ftrace_buffer_info *info = file->private_data;
8001 struct trace_iterator *iter = &info->iter;
8002
8003 mutex_lock(&trace_types_lock);
8004
8005 iter->tr->trace_ref--;
8006
8007 __trace_array_put(iter->tr);
8008
8009 if (info->spare)
8010 ring_buffer_free_read_page(iter->array_buffer->buffer,
8011 info->spare_cpu, info->spare);
8012 kvfree(info);
8013
8014 mutex_unlock(&trace_types_lock);
8015
8016 return 0;
8017}
8018
8019struct buffer_ref {
8020 struct trace_buffer *buffer;
8021 void *page;
8022 int cpu;
8023 refcount_t refcount;
8024};
8025
8026static void buffer_ref_release(struct buffer_ref *ref)
8027{
8028 if (!refcount_dec_and_test(&ref->refcount))
8029 return;
8030 ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
8031 kfree(ref);
8032}
8033
8034static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
8035 struct pipe_buffer *buf)
8036{
8037 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8038
8039 buffer_ref_release(ref);
8040 buf->private = 0;
8041}
8042
8043static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
8044 struct pipe_buffer *buf)
8045{
8046 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8047
8048 if (refcount_read(&ref->refcount) > INT_MAX/2)
8049 return false;
8050
8051 refcount_inc(&ref->refcount);
8052 return true;
8053}
8054
8055/* Pipe buffer operations for a buffer. */
8056static const struct pipe_buf_operations buffer_pipe_buf_ops = {
8057 .release = buffer_pipe_buf_release,
8058 .get = buffer_pipe_buf_get,
8059};
8060
8061/*
8062 * Callback from splice_to_pipe(), if we need to release some pages
8063 * at the end of the spd in case we error'ed out in filling the pipe.
8064 */
8065static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
8066{
8067 struct buffer_ref *ref =
8068 (struct buffer_ref *)spd->partial[i].private;
8069
8070 buffer_ref_release(ref);
8071 spd->partial[i].private = 0;
8072}
8073
8074static ssize_t
8075tracing_buffers_splice_read(struct file *file, loff_t *ppos,
8076 struct pipe_inode_info *pipe, size_t len,
8077 unsigned int flags)
8078{
8079 struct ftrace_buffer_info *info = file->private_data;
8080 struct trace_iterator *iter = &info->iter;
8081 struct partial_page partial_def[PIPE_DEF_BUFFERS];
8082 struct page *pages_def[PIPE_DEF_BUFFERS];
8083 struct splice_pipe_desc spd = {
8084 .pages = pages_def,
8085 .partial = partial_def,
8086 .nr_pages_max = PIPE_DEF_BUFFERS,
8087 .ops = &buffer_pipe_buf_ops,
8088 .spd_release = buffer_spd_release,
8089 };
8090 struct buffer_ref *ref;
8091 bool woken = false;
8092 int page_size;
8093 int entries, i;
8094 ssize_t ret = 0;
8095
8096#ifdef CONFIG_TRACER_MAX_TRACE
8097 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8098 return -EBUSY;
8099#endif
8100
8101 page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
8102 if (*ppos & (page_size - 1))
8103 return -EINVAL;
8104
8105 if (len & (page_size - 1)) {
8106 if (len < page_size)
8107 return -EINVAL;
8108 len &= (~(page_size - 1));
8109 }
8110
8111 if (splice_grow_spd(pipe, &spd))
8112 return -ENOMEM;
8113
8114 again:
8115 trace_access_lock(iter->cpu_file);
8116 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8117
8118 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= page_size) {
8119 struct page *page;
8120 int r;
8121
8122 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
8123 if (!ref) {
8124 ret = -ENOMEM;
8125 break;
8126 }
8127
8128 refcount_set(&ref->refcount, 1);
8129 ref->buffer = iter->array_buffer->buffer;
8130 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
8131 if (IS_ERR(ref->page)) {
8132 ret = PTR_ERR(ref->page);
8133 ref->page = NULL;
8134 kfree(ref);
8135 break;
8136 }
8137 ref->cpu = iter->cpu_file;
8138
8139 r = ring_buffer_read_page(ref->buffer, ref->page,
8140 len, iter->cpu_file, 1);
8141 if (r < 0) {
8142 ring_buffer_free_read_page(ref->buffer, ref->cpu,
8143 ref->page);
8144 kfree(ref);
8145 break;
8146 }
8147
8148 page = virt_to_page(ring_buffer_read_page_data(ref->page));
8149
8150 spd.pages[i] = page;
8151 spd.partial[i].len = page_size;
8152 spd.partial[i].offset = 0;
8153 spd.partial[i].private = (unsigned long)ref;
8154 spd.nr_pages++;
8155 *ppos += page_size;
8156
8157 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8158 }
8159
8160 trace_access_unlock(iter->cpu_file);
8161 spd.nr_pages = i;
8162
8163 /* did we read anything? */
8164 if (!spd.nr_pages) {
8165
8166 if (ret)
8167 goto out;
8168
8169 if (woken)
8170 goto out;
8171
8172 ret = -EAGAIN;
8173 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
8174 goto out;
8175
8176 ret = wait_on_pipe(iter, iter->snapshot ? 0 : iter->tr->buffer_percent);
8177 if (ret)
8178 goto out;
8179
8180 /* No need to wait after waking up when tracing is off */
8181 if (!tracer_tracing_is_on(iter->tr))
8182 goto out;
8183
8184 /* Iterate one more time to collect any new data then exit */
8185 woken = true;
8186
8187 goto again;
8188 }
8189
8190 ret = splice_to_pipe(pipe, &spd);
8191out:
8192 splice_shrink_spd(&spd);
8193
8194 return ret;
8195}
8196
8197/* An ioctl call with cmd 0 to the ring buffer file will wake up all waiters */
8198static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
8199{
8200 struct ftrace_buffer_info *info = file->private_data;
8201 struct trace_iterator *iter = &info->iter;
8202
8203 if (cmd)
8204 return -ENOIOCTLCMD;
8205
8206 mutex_lock(&trace_types_lock);
8207
8208 /* Make sure the waiters see the new wait_index */
8209 (void)atomic_fetch_inc_release(&iter->wait_index);
8210
8211 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
8212
8213 mutex_unlock(&trace_types_lock);
8214 return 0;
8215}
8216
8217static const struct file_operations tracing_buffers_fops = {
8218 .open = tracing_buffers_open,
8219 .read = tracing_buffers_read,
8220 .poll = tracing_buffers_poll,
8221 .release = tracing_buffers_release,
8222 .flush = tracing_buffers_flush,
8223 .splice_read = tracing_buffers_splice_read,
8224 .unlocked_ioctl = tracing_buffers_ioctl,
8225 .llseek = no_llseek,
8226};
8227
8228static ssize_t
8229tracing_stats_read(struct file *filp, char __user *ubuf,
8230 size_t count, loff_t *ppos)
8231{
8232 struct inode *inode = file_inode(filp);
8233 struct trace_array *tr = inode->i_private;
8234 struct array_buffer *trace_buf = &tr->array_buffer;
8235 int cpu = tracing_get_cpu(inode);
8236 struct trace_seq *s;
8237 unsigned long cnt;
8238 unsigned long long t;
8239 unsigned long usec_rem;
8240
8241 s = kmalloc(sizeof(*s), GFP_KERNEL);
8242 if (!s)
8243 return -ENOMEM;
8244
8245 trace_seq_init(s);
8246
8247 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
8248 trace_seq_printf(s, "entries: %ld\n", cnt);
8249
8250 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
8251 trace_seq_printf(s, "overrun: %ld\n", cnt);
8252
8253 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
8254 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
8255
8256 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
8257 trace_seq_printf(s, "bytes: %ld\n", cnt);
8258
8259 if (trace_clocks[tr->clock_id].in_ns) {
8260 /* local or global for trace_clock */
8261 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8262 usec_rem = do_div(t, USEC_PER_SEC);
8263 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
8264 t, usec_rem);
8265
8266 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer));
8267 usec_rem = do_div(t, USEC_PER_SEC);
8268 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
8269 } else {
8270 /* counter or tsc mode for trace_clock */
8271 trace_seq_printf(s, "oldest event ts: %llu\n",
8272 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8273
8274 trace_seq_printf(s, "now ts: %llu\n",
8275 ring_buffer_time_stamp(trace_buf->buffer));
8276 }
8277
8278 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
8279 trace_seq_printf(s, "dropped events: %ld\n", cnt);
8280
8281 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
8282 trace_seq_printf(s, "read events: %ld\n", cnt);
8283
8284 count = simple_read_from_buffer(ubuf, count, ppos,
8285 s->buffer, trace_seq_used(s));
8286
8287 kfree(s);
8288
8289 return count;
8290}
8291
8292static const struct file_operations tracing_stats_fops = {
8293 .open = tracing_open_generic_tr,
8294 .read = tracing_stats_read,
8295 .llseek = generic_file_llseek,
8296 .release = tracing_release_generic_tr,
8297};
8298
8299#ifdef CONFIG_DYNAMIC_FTRACE
8300
8301static ssize_t
8302tracing_read_dyn_info(struct file *filp, char __user *ubuf,
8303 size_t cnt, loff_t *ppos)
8304{
8305 ssize_t ret;
8306 char *buf;
8307 int r;
8308
8309 /* 256 should be plenty to hold the amount needed */
8310 buf = kmalloc(256, GFP_KERNEL);
8311 if (!buf)
8312 return -ENOMEM;
8313
8314 r = scnprintf(buf, 256, "%ld pages:%ld groups: %ld\n",
8315 ftrace_update_tot_cnt,
8316 ftrace_number_of_pages,
8317 ftrace_number_of_groups);
8318
8319 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8320 kfree(buf);
8321 return ret;
8322}
8323
8324static const struct file_operations tracing_dyn_info_fops = {
8325 .open = tracing_open_generic,
8326 .read = tracing_read_dyn_info,
8327 .llseek = generic_file_llseek,
8328};
8329#endif /* CONFIG_DYNAMIC_FTRACE */
8330
8331#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
8332static void
8333ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
8334 struct trace_array *tr, struct ftrace_probe_ops *ops,
8335 void *data)
8336{
8337 tracing_snapshot_instance(tr);
8338}
8339
8340static void
8341ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
8342 struct trace_array *tr, struct ftrace_probe_ops *ops,
8343 void *data)
8344{
8345 struct ftrace_func_mapper *mapper = data;
8346 long *count = NULL;
8347
8348 if (mapper)
8349 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8350
8351 if (count) {
8352
8353 if (*count <= 0)
8354 return;
8355
8356 (*count)--;
8357 }
8358
8359 tracing_snapshot_instance(tr);
8360}
8361
8362static int
8363ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
8364 struct ftrace_probe_ops *ops, void *data)
8365{
8366 struct ftrace_func_mapper *mapper = data;
8367 long *count = NULL;
8368
8369 seq_printf(m, "%ps:", (void *)ip);
8370
8371 seq_puts(m, "snapshot");
8372
8373 if (mapper)
8374 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8375
8376 if (count)
8377 seq_printf(m, ":count=%ld\n", *count);
8378 else
8379 seq_puts(m, ":unlimited\n");
8380
8381 return 0;
8382}
8383
8384static int
8385ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
8386 unsigned long ip, void *init_data, void **data)
8387{
8388 struct ftrace_func_mapper *mapper = *data;
8389
8390 if (!mapper) {
8391 mapper = allocate_ftrace_func_mapper();
8392 if (!mapper)
8393 return -ENOMEM;
8394 *data = mapper;
8395 }
8396
8397 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
8398}
8399
8400static void
8401ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
8402 unsigned long ip, void *data)
8403{
8404 struct ftrace_func_mapper *mapper = data;
8405
8406 if (!ip) {
8407 if (!mapper)
8408 return;
8409 free_ftrace_func_mapper(mapper, NULL);
8410 return;
8411 }
8412
8413 ftrace_func_mapper_remove_ip(mapper, ip);
8414}
8415
8416static struct ftrace_probe_ops snapshot_probe_ops = {
8417 .func = ftrace_snapshot,
8418 .print = ftrace_snapshot_print,
8419};
8420
8421static struct ftrace_probe_ops snapshot_count_probe_ops = {
8422 .func = ftrace_count_snapshot,
8423 .print = ftrace_snapshot_print,
8424 .init = ftrace_snapshot_init,
8425 .free = ftrace_snapshot_free,
8426};
8427
8428static int
8429ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
8430 char *glob, char *cmd, char *param, int enable)
8431{
8432 struct ftrace_probe_ops *ops;
8433 void *count = (void *)-1;
8434 char *number;
8435 int ret;
8436
8437 if (!tr)
8438 return -ENODEV;
8439
8440 /* hash funcs only work with set_ftrace_filter */
8441 if (!enable)
8442 return -EINVAL;
8443
8444 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
8445
8446 if (glob[0] == '!') {
8447 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
8448 if (!ret)
8449 tracing_disarm_snapshot(tr);
8450
8451 return ret;
8452 }
8453
8454 if (!param)
8455 goto out_reg;
8456
8457 number = strsep(¶m, ":");
8458
8459 if (!strlen(number))
8460 goto out_reg;
8461
8462 /*
8463 * We use the callback data field (which is a pointer)
8464 * as our counter.
8465 */
8466 ret = kstrtoul(number, 0, (unsigned long *)&count);
8467 if (ret)
8468 return ret;
8469
8470 out_reg:
8471 ret = tracing_arm_snapshot(tr);
8472 if (ret < 0)
8473 goto out;
8474
8475 ret = register_ftrace_function_probe(glob, tr, ops, count);
8476 if (ret < 0)
8477 tracing_disarm_snapshot(tr);
8478 out:
8479 return ret < 0 ? ret : 0;
8480}
8481
8482static struct ftrace_func_command ftrace_snapshot_cmd = {
8483 .name = "snapshot",
8484 .func = ftrace_trace_snapshot_callback,
8485};
8486
8487static __init int register_snapshot_cmd(void)
8488{
8489 return register_ftrace_command(&ftrace_snapshot_cmd);
8490}
8491#else
8492static inline __init int register_snapshot_cmd(void) { return 0; }
8493#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
8494
8495static struct dentry *tracing_get_dentry(struct trace_array *tr)
8496{
8497 if (WARN_ON(!tr->dir))
8498 return ERR_PTR(-ENODEV);
8499
8500 /* Top directory uses NULL as the parent */
8501 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
8502 return NULL;
8503
8504 /* All sub buffers have a descriptor */
8505 return tr->dir;
8506}
8507
8508static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
8509{
8510 struct dentry *d_tracer;
8511
8512 if (tr->percpu_dir)
8513 return tr->percpu_dir;
8514
8515 d_tracer = tracing_get_dentry(tr);
8516 if (IS_ERR(d_tracer))
8517 return NULL;
8518
8519 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
8520
8521 MEM_FAIL(!tr->percpu_dir,
8522 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
8523
8524 return tr->percpu_dir;
8525}
8526
8527static struct dentry *
8528trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
8529 void *data, long cpu, const struct file_operations *fops)
8530{
8531 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
8532
8533 if (ret) /* See tracing_get_cpu() */
8534 d_inode(ret)->i_cdev = (void *)(cpu + 1);
8535 return ret;
8536}
8537
8538static void
8539tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
8540{
8541 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
8542 struct dentry *d_cpu;
8543 char cpu_dir[30]; /* 30 characters should be more than enough */
8544
8545 if (!d_percpu)
8546 return;
8547
8548 snprintf(cpu_dir, 30, "cpu%ld", cpu);
8549 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
8550 if (!d_cpu) {
8551 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
8552 return;
8553 }
8554
8555 /* per cpu trace_pipe */
8556 trace_create_cpu_file("trace_pipe", TRACE_MODE_READ, d_cpu,
8557 tr, cpu, &tracing_pipe_fops);
8558
8559 /* per cpu trace */
8560 trace_create_cpu_file("trace", TRACE_MODE_WRITE, d_cpu,
8561 tr, cpu, &tracing_fops);
8562
8563 trace_create_cpu_file("trace_pipe_raw", TRACE_MODE_READ, d_cpu,
8564 tr, cpu, &tracing_buffers_fops);
8565
8566 trace_create_cpu_file("stats", TRACE_MODE_READ, d_cpu,
8567 tr, cpu, &tracing_stats_fops);
8568
8569 trace_create_cpu_file("buffer_size_kb", TRACE_MODE_READ, d_cpu,
8570 tr, cpu, &tracing_entries_fops);
8571
8572#ifdef CONFIG_TRACER_SNAPSHOT
8573 trace_create_cpu_file("snapshot", TRACE_MODE_WRITE, d_cpu,
8574 tr, cpu, &snapshot_fops);
8575
8576 trace_create_cpu_file("snapshot_raw", TRACE_MODE_READ, d_cpu,
8577 tr, cpu, &snapshot_raw_fops);
8578#endif
8579}
8580
8581#ifdef CONFIG_FTRACE_SELFTEST
8582/* Let selftest have access to static functions in this file */
8583#include "trace_selftest.c"
8584#endif
8585
8586static ssize_t
8587trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
8588 loff_t *ppos)
8589{
8590 struct trace_option_dentry *topt = filp->private_data;
8591 char *buf;
8592
8593 if (topt->flags->val & topt->opt->bit)
8594 buf = "1\n";
8595 else
8596 buf = "0\n";
8597
8598 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
8599}
8600
8601static ssize_t
8602trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
8603 loff_t *ppos)
8604{
8605 struct trace_option_dentry *topt = filp->private_data;
8606 unsigned long val;
8607 int ret;
8608
8609 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8610 if (ret)
8611 return ret;
8612
8613 if (val != 0 && val != 1)
8614 return -EINVAL;
8615
8616 if (!!(topt->flags->val & topt->opt->bit) != val) {
8617 mutex_lock(&trace_types_lock);
8618 ret = __set_tracer_option(topt->tr, topt->flags,
8619 topt->opt, !val);
8620 mutex_unlock(&trace_types_lock);
8621 if (ret)
8622 return ret;
8623 }
8624
8625 *ppos += cnt;
8626
8627 return cnt;
8628}
8629
8630static int tracing_open_options(struct inode *inode, struct file *filp)
8631{
8632 struct trace_option_dentry *topt = inode->i_private;
8633 int ret;
8634
8635 ret = tracing_check_open_get_tr(topt->tr);
8636 if (ret)
8637 return ret;
8638
8639 filp->private_data = inode->i_private;
8640 return 0;
8641}
8642
8643static int tracing_release_options(struct inode *inode, struct file *file)
8644{
8645 struct trace_option_dentry *topt = file->private_data;
8646
8647 trace_array_put(topt->tr);
8648 return 0;
8649}
8650
8651static const struct file_operations trace_options_fops = {
8652 .open = tracing_open_options,
8653 .read = trace_options_read,
8654 .write = trace_options_write,
8655 .llseek = generic_file_llseek,
8656 .release = tracing_release_options,
8657};
8658
8659/*
8660 * In order to pass in both the trace_array descriptor as well as the index
8661 * to the flag that the trace option file represents, the trace_array
8662 * has a character array of trace_flags_index[], which holds the index
8663 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
8664 * The address of this character array is passed to the flag option file
8665 * read/write callbacks.
8666 *
8667 * In order to extract both the index and the trace_array descriptor,
8668 * get_tr_index() uses the following algorithm.
8669 *
8670 * idx = *ptr;
8671 *
8672 * As the pointer itself contains the address of the index (remember
8673 * index[1] == 1).
8674 *
8675 * Then to get the trace_array descriptor, by subtracting that index
8676 * from the ptr, we get to the start of the index itself.
8677 *
8678 * ptr - idx == &index[0]
8679 *
8680 * Then a simple container_of() from that pointer gets us to the
8681 * trace_array descriptor.
8682 */
8683static void get_tr_index(void *data, struct trace_array **ptr,
8684 unsigned int *pindex)
8685{
8686 *pindex = *(unsigned char *)data;
8687
8688 *ptr = container_of(data - *pindex, struct trace_array,
8689 trace_flags_index);
8690}
8691
8692static ssize_t
8693trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
8694 loff_t *ppos)
8695{
8696 void *tr_index = filp->private_data;
8697 struct trace_array *tr;
8698 unsigned int index;
8699 char *buf;
8700
8701 get_tr_index(tr_index, &tr, &index);
8702
8703 if (tr->trace_flags & (1 << index))
8704 buf = "1\n";
8705 else
8706 buf = "0\n";
8707
8708 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
8709}
8710
8711static ssize_t
8712trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
8713 loff_t *ppos)
8714{
8715 void *tr_index = filp->private_data;
8716 struct trace_array *tr;
8717 unsigned int index;
8718 unsigned long val;
8719 int ret;
8720
8721 get_tr_index(tr_index, &tr, &index);
8722
8723 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8724 if (ret)
8725 return ret;
8726
8727 if (val != 0 && val != 1)
8728 return -EINVAL;
8729
8730 mutex_lock(&event_mutex);
8731 mutex_lock(&trace_types_lock);
8732 ret = set_tracer_flag(tr, 1 << index, val);
8733 mutex_unlock(&trace_types_lock);
8734 mutex_unlock(&event_mutex);
8735
8736 if (ret < 0)
8737 return ret;
8738
8739 *ppos += cnt;
8740
8741 return cnt;
8742}
8743
8744static const struct file_operations trace_options_core_fops = {
8745 .open = tracing_open_generic,
8746 .read = trace_options_core_read,
8747 .write = trace_options_core_write,
8748 .llseek = generic_file_llseek,
8749};
8750
8751struct dentry *trace_create_file(const char *name,
8752 umode_t mode,
8753 struct dentry *parent,
8754 void *data,
8755 const struct file_operations *fops)
8756{
8757 struct dentry *ret;
8758
8759 ret = tracefs_create_file(name, mode, parent, data, fops);
8760 if (!ret)
8761 pr_warn("Could not create tracefs '%s' entry\n", name);
8762
8763 return ret;
8764}
8765
8766
8767static struct dentry *trace_options_init_dentry(struct trace_array *tr)
8768{
8769 struct dentry *d_tracer;
8770
8771 if (tr->options)
8772 return tr->options;
8773
8774 d_tracer = tracing_get_dentry(tr);
8775 if (IS_ERR(d_tracer))
8776 return NULL;
8777
8778 tr->options = tracefs_create_dir("options", d_tracer);
8779 if (!tr->options) {
8780 pr_warn("Could not create tracefs directory 'options'\n");
8781 return NULL;
8782 }
8783
8784 return tr->options;
8785}
8786
8787static void
8788create_trace_option_file(struct trace_array *tr,
8789 struct trace_option_dentry *topt,
8790 struct tracer_flags *flags,
8791 struct tracer_opt *opt)
8792{
8793 struct dentry *t_options;
8794
8795 t_options = trace_options_init_dentry(tr);
8796 if (!t_options)
8797 return;
8798
8799 topt->flags = flags;
8800 topt->opt = opt;
8801 topt->tr = tr;
8802
8803 topt->entry = trace_create_file(opt->name, TRACE_MODE_WRITE,
8804 t_options, topt, &trace_options_fops);
8805
8806}
8807
8808static void
8809create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
8810{
8811 struct trace_option_dentry *topts;
8812 struct trace_options *tr_topts;
8813 struct tracer_flags *flags;
8814 struct tracer_opt *opts;
8815 int cnt;
8816 int i;
8817
8818 if (!tracer)
8819 return;
8820
8821 flags = tracer->flags;
8822
8823 if (!flags || !flags->opts)
8824 return;
8825
8826 /*
8827 * If this is an instance, only create flags for tracers
8828 * the instance may have.
8829 */
8830 if (!trace_ok_for_array(tracer, tr))
8831 return;
8832
8833 for (i = 0; i < tr->nr_topts; i++) {
8834 /* Make sure there's no duplicate flags. */
8835 if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
8836 return;
8837 }
8838
8839 opts = flags->opts;
8840
8841 for (cnt = 0; opts[cnt].name; cnt++)
8842 ;
8843
8844 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
8845 if (!topts)
8846 return;
8847
8848 tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
8849 GFP_KERNEL);
8850 if (!tr_topts) {
8851 kfree(topts);
8852 return;
8853 }
8854
8855 tr->topts = tr_topts;
8856 tr->topts[tr->nr_topts].tracer = tracer;
8857 tr->topts[tr->nr_topts].topts = topts;
8858 tr->nr_topts++;
8859
8860 for (cnt = 0; opts[cnt].name; cnt++) {
8861 create_trace_option_file(tr, &topts[cnt], flags,
8862 &opts[cnt]);
8863 MEM_FAIL(topts[cnt].entry == NULL,
8864 "Failed to create trace option: %s",
8865 opts[cnt].name);
8866 }
8867}
8868
8869static struct dentry *
8870create_trace_option_core_file(struct trace_array *tr,
8871 const char *option, long index)
8872{
8873 struct dentry *t_options;
8874
8875 t_options = trace_options_init_dentry(tr);
8876 if (!t_options)
8877 return NULL;
8878
8879 return trace_create_file(option, TRACE_MODE_WRITE, t_options,
8880 (void *)&tr->trace_flags_index[index],
8881 &trace_options_core_fops);
8882}
8883
8884static void create_trace_options_dir(struct trace_array *tr)
8885{
8886 struct dentry *t_options;
8887 bool top_level = tr == &global_trace;
8888 int i;
8889
8890 t_options = trace_options_init_dentry(tr);
8891 if (!t_options)
8892 return;
8893
8894 for (i = 0; trace_options[i]; i++) {
8895 if (top_level ||
8896 !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
8897 create_trace_option_core_file(tr, trace_options[i], i);
8898 }
8899}
8900
8901static ssize_t
8902rb_simple_read(struct file *filp, char __user *ubuf,
8903 size_t cnt, loff_t *ppos)
8904{
8905 struct trace_array *tr = filp->private_data;
8906 char buf[64];
8907 int r;
8908
8909 r = tracer_tracing_is_on(tr);
8910 r = sprintf(buf, "%d\n", r);
8911
8912 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8913}
8914
8915static ssize_t
8916rb_simple_write(struct file *filp, const char __user *ubuf,
8917 size_t cnt, loff_t *ppos)
8918{
8919 struct trace_array *tr = filp->private_data;
8920 struct trace_buffer *buffer = tr->array_buffer.buffer;
8921 unsigned long val;
8922 int ret;
8923
8924 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8925 if (ret)
8926 return ret;
8927
8928 if (buffer) {
8929 mutex_lock(&trace_types_lock);
8930 if (!!val == tracer_tracing_is_on(tr)) {
8931 val = 0; /* do nothing */
8932 } else if (val) {
8933 tracer_tracing_on(tr);
8934 if (tr->current_trace->start)
8935 tr->current_trace->start(tr);
8936 } else {
8937 tracer_tracing_off(tr);
8938 if (tr->current_trace->stop)
8939 tr->current_trace->stop(tr);
8940 /* Wake up any waiters */
8941 ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS);
8942 }
8943 mutex_unlock(&trace_types_lock);
8944 }
8945
8946 (*ppos)++;
8947
8948 return cnt;
8949}
8950
8951static const struct file_operations rb_simple_fops = {
8952 .open = tracing_open_generic_tr,
8953 .read = rb_simple_read,
8954 .write = rb_simple_write,
8955 .release = tracing_release_generic_tr,
8956 .llseek = default_llseek,
8957};
8958
8959static ssize_t
8960buffer_percent_read(struct file *filp, char __user *ubuf,
8961 size_t cnt, loff_t *ppos)
8962{
8963 struct trace_array *tr = filp->private_data;
8964 char buf[64];
8965 int r;
8966
8967 r = tr->buffer_percent;
8968 r = sprintf(buf, "%d\n", r);
8969
8970 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8971}
8972
8973static ssize_t
8974buffer_percent_write(struct file *filp, const char __user *ubuf,
8975 size_t cnt, loff_t *ppos)
8976{
8977 struct trace_array *tr = filp->private_data;
8978 unsigned long val;
8979 int ret;
8980
8981 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8982 if (ret)
8983 return ret;
8984
8985 if (val > 100)
8986 return -EINVAL;
8987
8988 tr->buffer_percent = val;
8989
8990 (*ppos)++;
8991
8992 return cnt;
8993}
8994
8995static const struct file_operations buffer_percent_fops = {
8996 .open = tracing_open_generic_tr,
8997 .read = buffer_percent_read,
8998 .write = buffer_percent_write,
8999 .release = tracing_release_generic_tr,
9000 .llseek = default_llseek,
9001};
9002
9003static ssize_t
9004buffer_subbuf_size_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
9005{
9006 struct trace_array *tr = filp->private_data;
9007 size_t size;
9008 char buf[64];
9009 int order;
9010 int r;
9011
9012 order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
9013 size = (PAGE_SIZE << order) / 1024;
9014
9015 r = sprintf(buf, "%zd\n", size);
9016
9017 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9018}
9019
9020static ssize_t
9021buffer_subbuf_size_write(struct file *filp, const char __user *ubuf,
9022 size_t cnt, loff_t *ppos)
9023{
9024 struct trace_array *tr = filp->private_data;
9025 unsigned long val;
9026 int old_order;
9027 int order;
9028 int pages;
9029 int ret;
9030
9031 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9032 if (ret)
9033 return ret;
9034
9035 val *= 1024; /* value passed in is in KB */
9036
9037 pages = DIV_ROUND_UP(val, PAGE_SIZE);
9038 order = fls(pages - 1);
9039
9040 /* limit between 1 and 128 system pages */
9041 if (order < 0 || order > 7)
9042 return -EINVAL;
9043
9044 /* Do not allow tracing while changing the order of the ring buffer */
9045 tracing_stop_tr(tr);
9046
9047 old_order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
9048 if (old_order == order)
9049 goto out;
9050
9051 ret = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, order);
9052 if (ret)
9053 goto out;
9054
9055#ifdef CONFIG_TRACER_MAX_TRACE
9056
9057 if (!tr->allocated_snapshot)
9058 goto out_max;
9059
9060 ret = ring_buffer_subbuf_order_set(tr->max_buffer.buffer, order);
9061 if (ret) {
9062 /* Put back the old order */
9063 cnt = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, old_order);
9064 if (WARN_ON_ONCE(cnt)) {
9065 /*
9066 * AARGH! We are left with different orders!
9067 * The max buffer is our "snapshot" buffer.
9068 * When a tracer needs a snapshot (one of the
9069 * latency tracers), it swaps the max buffer
9070 * with the saved snap shot. We succeeded to
9071 * update the order of the main buffer, but failed to
9072 * update the order of the max buffer. But when we tried
9073 * to reset the main buffer to the original size, we
9074 * failed there too. This is very unlikely to
9075 * happen, but if it does, warn and kill all
9076 * tracing.
9077 */
9078 tracing_disabled = 1;
9079 }
9080 goto out;
9081 }
9082 out_max:
9083#endif
9084 (*ppos)++;
9085 out:
9086 if (ret)
9087 cnt = ret;
9088 tracing_start_tr(tr);
9089 return cnt;
9090}
9091
9092static const struct file_operations buffer_subbuf_size_fops = {
9093 .open = tracing_open_generic_tr,
9094 .read = buffer_subbuf_size_read,
9095 .write = buffer_subbuf_size_write,
9096 .release = tracing_release_generic_tr,
9097 .llseek = default_llseek,
9098};
9099
9100static struct dentry *trace_instance_dir;
9101
9102static void
9103init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
9104
9105static int
9106allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size)
9107{
9108 enum ring_buffer_flags rb_flags;
9109
9110 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
9111
9112 buf->tr = tr;
9113
9114 buf->buffer = ring_buffer_alloc(size, rb_flags);
9115 if (!buf->buffer)
9116 return -ENOMEM;
9117
9118 buf->data = alloc_percpu(struct trace_array_cpu);
9119 if (!buf->data) {
9120 ring_buffer_free(buf->buffer);
9121 buf->buffer = NULL;
9122 return -ENOMEM;
9123 }
9124
9125 /* Allocate the first page for all buffers */
9126 set_buffer_entries(&tr->array_buffer,
9127 ring_buffer_size(tr->array_buffer.buffer, 0));
9128
9129 return 0;
9130}
9131
9132static void free_trace_buffer(struct array_buffer *buf)
9133{
9134 if (buf->buffer) {
9135 ring_buffer_free(buf->buffer);
9136 buf->buffer = NULL;
9137 free_percpu(buf->data);
9138 buf->data = NULL;
9139 }
9140}
9141
9142static int allocate_trace_buffers(struct trace_array *tr, int size)
9143{
9144 int ret;
9145
9146 ret = allocate_trace_buffer(tr, &tr->array_buffer, size);
9147 if (ret)
9148 return ret;
9149
9150#ifdef CONFIG_TRACER_MAX_TRACE
9151 ret = allocate_trace_buffer(tr, &tr->max_buffer,
9152 allocate_snapshot ? size : 1);
9153 if (MEM_FAIL(ret, "Failed to allocate trace buffer\n")) {
9154 free_trace_buffer(&tr->array_buffer);
9155 return -ENOMEM;
9156 }
9157 tr->allocated_snapshot = allocate_snapshot;
9158
9159 allocate_snapshot = false;
9160#endif
9161
9162 return 0;
9163}
9164
9165static void free_trace_buffers(struct trace_array *tr)
9166{
9167 if (!tr)
9168 return;
9169
9170 free_trace_buffer(&tr->array_buffer);
9171
9172#ifdef CONFIG_TRACER_MAX_TRACE
9173 free_trace_buffer(&tr->max_buffer);
9174#endif
9175}
9176
9177static void init_trace_flags_index(struct trace_array *tr)
9178{
9179 int i;
9180
9181 /* Used by the trace options files */
9182 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
9183 tr->trace_flags_index[i] = i;
9184}
9185
9186static void __update_tracer_options(struct trace_array *tr)
9187{
9188 struct tracer *t;
9189
9190 for (t = trace_types; t; t = t->next)
9191 add_tracer_options(tr, t);
9192}
9193
9194static void update_tracer_options(struct trace_array *tr)
9195{
9196 mutex_lock(&trace_types_lock);
9197 tracer_options_updated = true;
9198 __update_tracer_options(tr);
9199 mutex_unlock(&trace_types_lock);
9200}
9201
9202/* Must have trace_types_lock held */
9203struct trace_array *trace_array_find(const char *instance)
9204{
9205 struct trace_array *tr, *found = NULL;
9206
9207 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9208 if (tr->name && strcmp(tr->name, instance) == 0) {
9209 found = tr;
9210 break;
9211 }
9212 }
9213
9214 return found;
9215}
9216
9217struct trace_array *trace_array_find_get(const char *instance)
9218{
9219 struct trace_array *tr;
9220
9221 mutex_lock(&trace_types_lock);
9222 tr = trace_array_find(instance);
9223 if (tr)
9224 tr->ref++;
9225 mutex_unlock(&trace_types_lock);
9226
9227 return tr;
9228}
9229
9230static int trace_array_create_dir(struct trace_array *tr)
9231{
9232 int ret;
9233
9234 tr->dir = tracefs_create_dir(tr->name, trace_instance_dir);
9235 if (!tr->dir)
9236 return -EINVAL;
9237
9238 ret = event_trace_add_tracer(tr->dir, tr);
9239 if (ret) {
9240 tracefs_remove(tr->dir);
9241 return ret;
9242 }
9243
9244 init_tracer_tracefs(tr, tr->dir);
9245 __update_tracer_options(tr);
9246
9247 return ret;
9248}
9249
9250static struct trace_array *
9251trace_array_create_systems(const char *name, const char *systems)
9252{
9253 struct trace_array *tr;
9254 int ret;
9255
9256 ret = -ENOMEM;
9257 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
9258 if (!tr)
9259 return ERR_PTR(ret);
9260
9261 tr->name = kstrdup(name, GFP_KERNEL);
9262 if (!tr->name)
9263 goto out_free_tr;
9264
9265 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
9266 goto out_free_tr;
9267
9268 if (!zalloc_cpumask_var(&tr->pipe_cpumask, GFP_KERNEL))
9269 goto out_free_tr;
9270
9271 if (systems) {
9272 tr->system_names = kstrdup_const(systems, GFP_KERNEL);
9273 if (!tr->system_names)
9274 goto out_free_tr;
9275 }
9276
9277 tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
9278
9279 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
9280
9281 raw_spin_lock_init(&tr->start_lock);
9282
9283 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
9284#ifdef CONFIG_TRACER_MAX_TRACE
9285 spin_lock_init(&tr->snapshot_trigger_lock);
9286#endif
9287 tr->current_trace = &nop_trace;
9288
9289 INIT_LIST_HEAD(&tr->systems);
9290 INIT_LIST_HEAD(&tr->events);
9291 INIT_LIST_HEAD(&tr->hist_vars);
9292 INIT_LIST_HEAD(&tr->err_log);
9293
9294 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
9295 goto out_free_tr;
9296
9297 /* The ring buffer is defaultly expanded */
9298 trace_set_ring_buffer_expanded(tr);
9299
9300 if (ftrace_allocate_ftrace_ops(tr) < 0)
9301 goto out_free_tr;
9302
9303 ftrace_init_trace_array(tr);
9304
9305 init_trace_flags_index(tr);
9306
9307 if (trace_instance_dir) {
9308 ret = trace_array_create_dir(tr);
9309 if (ret)
9310 goto out_free_tr;
9311 } else
9312 __trace_early_add_events(tr);
9313
9314 list_add(&tr->list, &ftrace_trace_arrays);
9315
9316 tr->ref++;
9317
9318 return tr;
9319
9320 out_free_tr:
9321 ftrace_free_ftrace_ops(tr);
9322 free_trace_buffers(tr);
9323 free_cpumask_var(tr->pipe_cpumask);
9324 free_cpumask_var(tr->tracing_cpumask);
9325 kfree_const(tr->system_names);
9326 kfree(tr->name);
9327 kfree(tr);
9328
9329 return ERR_PTR(ret);
9330}
9331
9332static struct trace_array *trace_array_create(const char *name)
9333{
9334 return trace_array_create_systems(name, NULL);
9335}
9336
9337static int instance_mkdir(const char *name)
9338{
9339 struct trace_array *tr;
9340 int ret;
9341
9342 mutex_lock(&event_mutex);
9343 mutex_lock(&trace_types_lock);
9344
9345 ret = -EEXIST;
9346 if (trace_array_find(name))
9347 goto out_unlock;
9348
9349 tr = trace_array_create(name);
9350
9351 ret = PTR_ERR_OR_ZERO(tr);
9352
9353out_unlock:
9354 mutex_unlock(&trace_types_lock);
9355 mutex_unlock(&event_mutex);
9356 return ret;
9357}
9358
9359/**
9360 * trace_array_get_by_name - Create/Lookup a trace array, given its name.
9361 * @name: The name of the trace array to be looked up/created.
9362 * @systems: A list of systems to create event directories for (NULL for all)
9363 *
9364 * Returns pointer to trace array with given name.
9365 * NULL, if it cannot be created.
9366 *
9367 * NOTE: This function increments the reference counter associated with the
9368 * trace array returned. This makes sure it cannot be freed while in use.
9369 * Use trace_array_put() once the trace array is no longer needed.
9370 * If the trace_array is to be freed, trace_array_destroy() needs to
9371 * be called after the trace_array_put(), or simply let user space delete
9372 * it from the tracefs instances directory. But until the
9373 * trace_array_put() is called, user space can not delete it.
9374 *
9375 */
9376struct trace_array *trace_array_get_by_name(const char *name, const char *systems)
9377{
9378 struct trace_array *tr;
9379
9380 mutex_lock(&event_mutex);
9381 mutex_lock(&trace_types_lock);
9382
9383 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9384 if (tr->name && strcmp(tr->name, name) == 0)
9385 goto out_unlock;
9386 }
9387
9388 tr = trace_array_create_systems(name, systems);
9389
9390 if (IS_ERR(tr))
9391 tr = NULL;
9392out_unlock:
9393 if (tr)
9394 tr->ref++;
9395
9396 mutex_unlock(&trace_types_lock);
9397 mutex_unlock(&event_mutex);
9398 return tr;
9399}
9400EXPORT_SYMBOL_GPL(trace_array_get_by_name);
9401
9402static int __remove_instance(struct trace_array *tr)
9403{
9404 int i;
9405
9406 /* Reference counter for a newly created trace array = 1. */
9407 if (tr->ref > 1 || (tr->current_trace && tr->trace_ref))
9408 return -EBUSY;
9409
9410 list_del(&tr->list);
9411
9412 /* Disable all the flags that were enabled coming in */
9413 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
9414 if ((1 << i) & ZEROED_TRACE_FLAGS)
9415 set_tracer_flag(tr, 1 << i, 0);
9416 }
9417
9418 tracing_set_nop(tr);
9419 clear_ftrace_function_probes(tr);
9420 event_trace_del_tracer(tr);
9421 ftrace_clear_pids(tr);
9422 ftrace_destroy_function_files(tr);
9423 tracefs_remove(tr->dir);
9424 free_percpu(tr->last_func_repeats);
9425 free_trace_buffers(tr);
9426 clear_tracing_err_log(tr);
9427
9428 for (i = 0; i < tr->nr_topts; i++) {
9429 kfree(tr->topts[i].topts);
9430 }
9431 kfree(tr->topts);
9432
9433 free_cpumask_var(tr->pipe_cpumask);
9434 free_cpumask_var(tr->tracing_cpumask);
9435 kfree_const(tr->system_names);
9436 kfree(tr->name);
9437 kfree(tr);
9438
9439 return 0;
9440}
9441
9442int trace_array_destroy(struct trace_array *this_tr)
9443{
9444 struct trace_array *tr;
9445 int ret;
9446
9447 if (!this_tr)
9448 return -EINVAL;
9449
9450 mutex_lock(&event_mutex);
9451 mutex_lock(&trace_types_lock);
9452
9453 ret = -ENODEV;
9454
9455 /* Making sure trace array exists before destroying it. */
9456 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9457 if (tr == this_tr) {
9458 ret = __remove_instance(tr);
9459 break;
9460 }
9461 }
9462
9463 mutex_unlock(&trace_types_lock);
9464 mutex_unlock(&event_mutex);
9465
9466 return ret;
9467}
9468EXPORT_SYMBOL_GPL(trace_array_destroy);
9469
9470static int instance_rmdir(const char *name)
9471{
9472 struct trace_array *tr;
9473 int ret;
9474
9475 mutex_lock(&event_mutex);
9476 mutex_lock(&trace_types_lock);
9477
9478 ret = -ENODEV;
9479 tr = trace_array_find(name);
9480 if (tr)
9481 ret = __remove_instance(tr);
9482
9483 mutex_unlock(&trace_types_lock);
9484 mutex_unlock(&event_mutex);
9485
9486 return ret;
9487}
9488
9489static __init void create_trace_instances(struct dentry *d_tracer)
9490{
9491 struct trace_array *tr;
9492
9493 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
9494 instance_mkdir,
9495 instance_rmdir);
9496 if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))
9497 return;
9498
9499 mutex_lock(&event_mutex);
9500 mutex_lock(&trace_types_lock);
9501
9502 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9503 if (!tr->name)
9504 continue;
9505 if (MEM_FAIL(trace_array_create_dir(tr) < 0,
9506 "Failed to create instance directory\n"))
9507 break;
9508 }
9509
9510 mutex_unlock(&trace_types_lock);
9511 mutex_unlock(&event_mutex);
9512}
9513
9514static void
9515init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
9516{
9517 int cpu;
9518
9519 trace_create_file("available_tracers", TRACE_MODE_READ, d_tracer,
9520 tr, &show_traces_fops);
9521
9522 trace_create_file("current_tracer", TRACE_MODE_WRITE, d_tracer,
9523 tr, &set_tracer_fops);
9524
9525 trace_create_file("tracing_cpumask", TRACE_MODE_WRITE, d_tracer,
9526 tr, &tracing_cpumask_fops);
9527
9528 trace_create_file("trace_options", TRACE_MODE_WRITE, d_tracer,
9529 tr, &tracing_iter_fops);
9530
9531 trace_create_file("trace", TRACE_MODE_WRITE, d_tracer,
9532 tr, &tracing_fops);
9533
9534 trace_create_file("trace_pipe", TRACE_MODE_READ, d_tracer,
9535 tr, &tracing_pipe_fops);
9536
9537 trace_create_file("buffer_size_kb", TRACE_MODE_WRITE, d_tracer,
9538 tr, &tracing_entries_fops);
9539
9540 trace_create_file("buffer_total_size_kb", TRACE_MODE_READ, d_tracer,
9541 tr, &tracing_total_entries_fops);
9542
9543 trace_create_file("free_buffer", 0200, d_tracer,
9544 tr, &tracing_free_buffer_fops);
9545
9546 trace_create_file("trace_marker", 0220, d_tracer,
9547 tr, &tracing_mark_fops);
9548
9549 tr->trace_marker_file = __find_event_file(tr, "ftrace", "print");
9550
9551 trace_create_file("trace_marker_raw", 0220, d_tracer,
9552 tr, &tracing_mark_raw_fops);
9553
9554 trace_create_file("trace_clock", TRACE_MODE_WRITE, d_tracer, tr,
9555 &trace_clock_fops);
9556
9557 trace_create_file("tracing_on", TRACE_MODE_WRITE, d_tracer,
9558 tr, &rb_simple_fops);
9559
9560 trace_create_file("timestamp_mode", TRACE_MODE_READ, d_tracer, tr,
9561 &trace_time_stamp_mode_fops);
9562
9563 tr->buffer_percent = 50;
9564
9565 trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer,
9566 tr, &buffer_percent_fops);
9567
9568 trace_create_file("buffer_subbuf_size_kb", TRACE_MODE_WRITE, d_tracer,
9569 tr, &buffer_subbuf_size_fops);
9570
9571 create_trace_options_dir(tr);
9572
9573#ifdef CONFIG_TRACER_MAX_TRACE
9574 trace_create_maxlat_file(tr, d_tracer);
9575#endif
9576
9577 if (ftrace_create_function_files(tr, d_tracer))
9578 MEM_FAIL(1, "Could not allocate function filter files");
9579
9580#ifdef CONFIG_TRACER_SNAPSHOT
9581 trace_create_file("snapshot", TRACE_MODE_WRITE, d_tracer,
9582 tr, &snapshot_fops);
9583#endif
9584
9585 trace_create_file("error_log", TRACE_MODE_WRITE, d_tracer,
9586 tr, &tracing_err_log_fops);
9587
9588 for_each_tracing_cpu(cpu)
9589 tracing_init_tracefs_percpu(tr, cpu);
9590
9591 ftrace_init_tracefs(tr, d_tracer);
9592}
9593
9594static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
9595{
9596 struct vfsmount *mnt;
9597 struct file_system_type *type;
9598
9599 /*
9600 * To maintain backward compatibility for tools that mount
9601 * debugfs to get to the tracing facility, tracefs is automatically
9602 * mounted to the debugfs/tracing directory.
9603 */
9604 type = get_fs_type("tracefs");
9605 if (!type)
9606 return NULL;
9607 mnt = vfs_submount(mntpt, type, "tracefs", NULL);
9608 put_filesystem(type);
9609 if (IS_ERR(mnt))
9610 return NULL;
9611 mntget(mnt);
9612
9613 return mnt;
9614}
9615
9616/**
9617 * tracing_init_dentry - initialize top level trace array
9618 *
9619 * This is called when creating files or directories in the tracing
9620 * directory. It is called via fs_initcall() by any of the boot up code
9621 * and expects to return the dentry of the top level tracing directory.
9622 */
9623int tracing_init_dentry(void)
9624{
9625 struct trace_array *tr = &global_trace;
9626
9627 if (security_locked_down(LOCKDOWN_TRACEFS)) {
9628 pr_warn("Tracing disabled due to lockdown\n");
9629 return -EPERM;
9630 }
9631
9632 /* The top level trace array uses NULL as parent */
9633 if (tr->dir)
9634 return 0;
9635
9636 if (WARN_ON(!tracefs_initialized()))
9637 return -ENODEV;
9638
9639 /*
9640 * As there may still be users that expect the tracing
9641 * files to exist in debugfs/tracing, we must automount
9642 * the tracefs file system there, so older tools still
9643 * work with the newer kernel.
9644 */
9645 tr->dir = debugfs_create_automount("tracing", NULL,
9646 trace_automount, NULL);
9647
9648 return 0;
9649}
9650
9651extern struct trace_eval_map *__start_ftrace_eval_maps[];
9652extern struct trace_eval_map *__stop_ftrace_eval_maps[];
9653
9654static struct workqueue_struct *eval_map_wq __initdata;
9655static struct work_struct eval_map_work __initdata;
9656static struct work_struct tracerfs_init_work __initdata;
9657
9658static void __init eval_map_work_func(struct work_struct *work)
9659{
9660 int len;
9661
9662 len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
9663 trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
9664}
9665
9666static int __init trace_eval_init(void)
9667{
9668 INIT_WORK(&eval_map_work, eval_map_work_func);
9669
9670 eval_map_wq = alloc_workqueue("eval_map_wq", WQ_UNBOUND, 0);
9671 if (!eval_map_wq) {
9672 pr_err("Unable to allocate eval_map_wq\n");
9673 /* Do work here */
9674 eval_map_work_func(&eval_map_work);
9675 return -ENOMEM;
9676 }
9677
9678 queue_work(eval_map_wq, &eval_map_work);
9679 return 0;
9680}
9681
9682subsys_initcall(trace_eval_init);
9683
9684static int __init trace_eval_sync(void)
9685{
9686 /* Make sure the eval map updates are finished */
9687 if (eval_map_wq)
9688 destroy_workqueue(eval_map_wq);
9689 return 0;
9690}
9691
9692late_initcall_sync(trace_eval_sync);
9693
9694
9695#ifdef CONFIG_MODULES
9696static void trace_module_add_evals(struct module *mod)
9697{
9698 if (!mod->num_trace_evals)
9699 return;
9700
9701 /*
9702 * Modules with bad taint do not have events created, do
9703 * not bother with enums either.
9704 */
9705 if (trace_module_has_bad_taint(mod))
9706 return;
9707
9708 trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
9709}
9710
9711#ifdef CONFIG_TRACE_EVAL_MAP_FILE
9712static void trace_module_remove_evals(struct module *mod)
9713{
9714 union trace_eval_map_item *map;
9715 union trace_eval_map_item **last = &trace_eval_maps;
9716
9717 if (!mod->num_trace_evals)
9718 return;
9719
9720 mutex_lock(&trace_eval_mutex);
9721
9722 map = trace_eval_maps;
9723
9724 while (map) {
9725 if (map->head.mod == mod)
9726 break;
9727 map = trace_eval_jmp_to_tail(map);
9728 last = &map->tail.next;
9729 map = map->tail.next;
9730 }
9731 if (!map)
9732 goto out;
9733
9734 *last = trace_eval_jmp_to_tail(map)->tail.next;
9735 kfree(map);
9736 out:
9737 mutex_unlock(&trace_eval_mutex);
9738}
9739#else
9740static inline void trace_module_remove_evals(struct module *mod) { }
9741#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
9742
9743static int trace_module_notify(struct notifier_block *self,
9744 unsigned long val, void *data)
9745{
9746 struct module *mod = data;
9747
9748 switch (val) {
9749 case MODULE_STATE_COMING:
9750 trace_module_add_evals(mod);
9751 break;
9752 case MODULE_STATE_GOING:
9753 trace_module_remove_evals(mod);
9754 break;
9755 }
9756
9757 return NOTIFY_OK;
9758}
9759
9760static struct notifier_block trace_module_nb = {
9761 .notifier_call = trace_module_notify,
9762 .priority = 0,
9763};
9764#endif /* CONFIG_MODULES */
9765
9766static __init void tracer_init_tracefs_work_func(struct work_struct *work)
9767{
9768
9769 event_trace_init();
9770
9771 init_tracer_tracefs(&global_trace, NULL);
9772 ftrace_init_tracefs_toplevel(&global_trace, NULL);
9773
9774 trace_create_file("tracing_thresh", TRACE_MODE_WRITE, NULL,
9775 &global_trace, &tracing_thresh_fops);
9776
9777 trace_create_file("README", TRACE_MODE_READ, NULL,
9778 NULL, &tracing_readme_fops);
9779
9780 trace_create_file("saved_cmdlines", TRACE_MODE_READ, NULL,
9781 NULL, &tracing_saved_cmdlines_fops);
9782
9783 trace_create_file("saved_cmdlines_size", TRACE_MODE_WRITE, NULL,
9784 NULL, &tracing_saved_cmdlines_size_fops);
9785
9786 trace_create_file("saved_tgids", TRACE_MODE_READ, NULL,
9787 NULL, &tracing_saved_tgids_fops);
9788
9789 trace_create_eval_file(NULL);
9790
9791#ifdef CONFIG_MODULES
9792 register_module_notifier(&trace_module_nb);
9793#endif
9794
9795#ifdef CONFIG_DYNAMIC_FTRACE
9796 trace_create_file("dyn_ftrace_total_info", TRACE_MODE_READ, NULL,
9797 NULL, &tracing_dyn_info_fops);
9798#endif
9799
9800 create_trace_instances(NULL);
9801
9802 update_tracer_options(&global_trace);
9803}
9804
9805static __init int tracer_init_tracefs(void)
9806{
9807 int ret;
9808
9809 trace_access_lock_init();
9810
9811 ret = tracing_init_dentry();
9812 if (ret)
9813 return 0;
9814
9815 if (eval_map_wq) {
9816 INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func);
9817 queue_work(eval_map_wq, &tracerfs_init_work);
9818 } else {
9819 tracer_init_tracefs_work_func(NULL);
9820 }
9821
9822 rv_init_interface();
9823
9824 return 0;
9825}
9826
9827fs_initcall(tracer_init_tracefs);
9828
9829static int trace_die_panic_handler(struct notifier_block *self,
9830 unsigned long ev, void *unused);
9831
9832static struct notifier_block trace_panic_notifier = {
9833 .notifier_call = trace_die_panic_handler,
9834 .priority = INT_MAX - 1,
9835};
9836
9837static struct notifier_block trace_die_notifier = {
9838 .notifier_call = trace_die_panic_handler,
9839 .priority = INT_MAX - 1,
9840};
9841
9842/*
9843 * The idea is to execute the following die/panic callback early, in order
9844 * to avoid showing irrelevant information in the trace (like other panic
9845 * notifier functions); we are the 2nd to run, after hung_task/rcu_stall
9846 * warnings get disabled (to prevent potential log flooding).
9847 */
9848static int trace_die_panic_handler(struct notifier_block *self,
9849 unsigned long ev, void *unused)
9850{
9851 if (!ftrace_dump_on_oops_enabled())
9852 return NOTIFY_DONE;
9853
9854 /* The die notifier requires DIE_OOPS to trigger */
9855 if (self == &trace_die_notifier && ev != DIE_OOPS)
9856 return NOTIFY_DONE;
9857
9858 ftrace_dump(DUMP_PARAM);
9859
9860 return NOTIFY_DONE;
9861}
9862
9863/*
9864 * printk is set to max of 1024, we really don't need it that big.
9865 * Nothing should be printing 1000 characters anyway.
9866 */
9867#define TRACE_MAX_PRINT 1000
9868
9869/*
9870 * Define here KERN_TRACE so that we have one place to modify
9871 * it if we decide to change what log level the ftrace dump
9872 * should be at.
9873 */
9874#define KERN_TRACE KERN_EMERG
9875
9876void
9877trace_printk_seq(struct trace_seq *s)
9878{
9879 /* Probably should print a warning here. */
9880 if (s->seq.len >= TRACE_MAX_PRINT)
9881 s->seq.len = TRACE_MAX_PRINT;
9882
9883 /*
9884 * More paranoid code. Although the buffer size is set to
9885 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
9886 * an extra layer of protection.
9887 */
9888 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
9889 s->seq.len = s->seq.size - 1;
9890
9891 /* should be zero ended, but we are paranoid. */
9892 s->buffer[s->seq.len] = 0;
9893
9894 printk(KERN_TRACE "%s", s->buffer);
9895
9896 trace_seq_init(s);
9897}
9898
9899static void trace_init_iter(struct trace_iterator *iter, struct trace_array *tr)
9900{
9901 iter->tr = tr;
9902 iter->trace = iter->tr->current_trace;
9903 iter->cpu_file = RING_BUFFER_ALL_CPUS;
9904 iter->array_buffer = &tr->array_buffer;
9905
9906 if (iter->trace && iter->trace->open)
9907 iter->trace->open(iter);
9908
9909 /* Annotate start of buffers if we had overruns */
9910 if (ring_buffer_overruns(iter->array_buffer->buffer))
9911 iter->iter_flags |= TRACE_FILE_ANNOTATE;
9912
9913 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
9914 if (trace_clocks[iter->tr->clock_id].in_ns)
9915 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
9916
9917 /* Can not use kmalloc for iter.temp and iter.fmt */
9918 iter->temp = static_temp_buf;
9919 iter->temp_size = STATIC_TEMP_BUF_SIZE;
9920 iter->fmt = static_fmt_buf;
9921 iter->fmt_size = STATIC_FMT_BUF_SIZE;
9922}
9923
9924void trace_init_global_iter(struct trace_iterator *iter)
9925{
9926 trace_init_iter(iter, &global_trace);
9927}
9928
9929static void ftrace_dump_one(struct trace_array *tr, enum ftrace_dump_mode dump_mode)
9930{
9931 /* use static because iter can be a bit big for the stack */
9932 static struct trace_iterator iter;
9933 unsigned int old_userobj;
9934 unsigned long flags;
9935 int cnt = 0, cpu;
9936
9937 /*
9938 * Always turn off tracing when we dump.
9939 * We don't need to show trace output of what happens
9940 * between multiple crashes.
9941 *
9942 * If the user does a sysrq-z, then they can re-enable
9943 * tracing with echo 1 > tracing_on.
9944 */
9945 tracer_tracing_off(tr);
9946
9947 local_irq_save(flags);
9948
9949 /* Simulate the iterator */
9950 trace_init_iter(&iter, tr);
9951
9952 for_each_tracing_cpu(cpu) {
9953 atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
9954 }
9955
9956 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
9957
9958 /* don't look at user memory in panic mode */
9959 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
9960
9961 if (dump_mode == DUMP_ORIG)
9962 iter.cpu_file = raw_smp_processor_id();
9963 else
9964 iter.cpu_file = RING_BUFFER_ALL_CPUS;
9965
9966 if (tr == &global_trace)
9967 printk(KERN_TRACE "Dumping ftrace buffer:\n");
9968 else
9969 printk(KERN_TRACE "Dumping ftrace instance %s buffer:\n", tr->name);
9970
9971 /* Did function tracer already get disabled? */
9972 if (ftrace_is_dead()) {
9973 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
9974 printk("# MAY BE MISSING FUNCTION EVENTS\n");
9975 }
9976
9977 /*
9978 * We need to stop all tracing on all CPUS to read
9979 * the next buffer. This is a bit expensive, but is
9980 * not done often. We fill all what we can read,
9981 * and then release the locks again.
9982 */
9983
9984 while (!trace_empty(&iter)) {
9985
9986 if (!cnt)
9987 printk(KERN_TRACE "---------------------------------\n");
9988
9989 cnt++;
9990
9991 trace_iterator_reset(&iter);
9992 iter.iter_flags |= TRACE_FILE_LAT_FMT;
9993
9994 if (trace_find_next_entry_inc(&iter) != NULL) {
9995 int ret;
9996
9997 ret = print_trace_line(&iter);
9998 if (ret != TRACE_TYPE_NO_CONSUME)
9999 trace_consume(&iter);
10000 }
10001 touch_nmi_watchdog();
10002
10003 trace_printk_seq(&iter.seq);
10004 }
10005
10006 if (!cnt)
10007 printk(KERN_TRACE " (ftrace buffer empty)\n");
10008 else
10009 printk(KERN_TRACE "---------------------------------\n");
10010
10011 tr->trace_flags |= old_userobj;
10012
10013 for_each_tracing_cpu(cpu) {
10014 atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
10015 }
10016 local_irq_restore(flags);
10017}
10018
10019static void ftrace_dump_by_param(void)
10020{
10021 bool first_param = true;
10022 char dump_param[MAX_TRACER_SIZE];
10023 char *buf, *token, *inst_name;
10024 struct trace_array *tr;
10025
10026 strscpy(dump_param, ftrace_dump_on_oops, MAX_TRACER_SIZE);
10027 buf = dump_param;
10028
10029 while ((token = strsep(&buf, ",")) != NULL) {
10030 if (first_param) {
10031 first_param = false;
10032 if (!strcmp("0", token))
10033 continue;
10034 else if (!strcmp("1", token)) {
10035 ftrace_dump_one(&global_trace, DUMP_ALL);
10036 continue;
10037 }
10038 else if (!strcmp("2", token) ||
10039 !strcmp("orig_cpu", token)) {
10040 ftrace_dump_one(&global_trace, DUMP_ORIG);
10041 continue;
10042 }
10043 }
10044
10045 inst_name = strsep(&token, "=");
10046 tr = trace_array_find(inst_name);
10047 if (!tr) {
10048 printk(KERN_TRACE "Instance %s not found\n", inst_name);
10049 continue;
10050 }
10051
10052 if (token && (!strcmp("2", token) ||
10053 !strcmp("orig_cpu", token)))
10054 ftrace_dump_one(tr, DUMP_ORIG);
10055 else
10056 ftrace_dump_one(tr, DUMP_ALL);
10057 }
10058}
10059
10060void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
10061{
10062 static atomic_t dump_running;
10063
10064 /* Only allow one dump user at a time. */
10065 if (atomic_inc_return(&dump_running) != 1) {
10066 atomic_dec(&dump_running);
10067 return;
10068 }
10069
10070 switch (oops_dump_mode) {
10071 case DUMP_ALL:
10072 ftrace_dump_one(&global_trace, DUMP_ALL);
10073 break;
10074 case DUMP_ORIG:
10075 ftrace_dump_one(&global_trace, DUMP_ORIG);
10076 break;
10077 case DUMP_PARAM:
10078 ftrace_dump_by_param();
10079 break;
10080 case DUMP_NONE:
10081 break;
10082 default:
10083 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
10084 ftrace_dump_one(&global_trace, DUMP_ALL);
10085 }
10086
10087 atomic_dec(&dump_running);
10088}
10089EXPORT_SYMBOL_GPL(ftrace_dump);
10090
10091#define WRITE_BUFSIZE 4096
10092
10093ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
10094 size_t count, loff_t *ppos,
10095 int (*createfn)(const char *))
10096{
10097 char *kbuf, *buf, *tmp;
10098 int ret = 0;
10099 size_t done = 0;
10100 size_t size;
10101
10102 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
10103 if (!kbuf)
10104 return -ENOMEM;
10105
10106 while (done < count) {
10107 size = count - done;
10108
10109 if (size >= WRITE_BUFSIZE)
10110 size = WRITE_BUFSIZE - 1;
10111
10112 if (copy_from_user(kbuf, buffer + done, size)) {
10113 ret = -EFAULT;
10114 goto out;
10115 }
10116 kbuf[size] = '\0';
10117 buf = kbuf;
10118 do {
10119 tmp = strchr(buf, '\n');
10120 if (tmp) {
10121 *tmp = '\0';
10122 size = tmp - buf + 1;
10123 } else {
10124 size = strlen(buf);
10125 if (done + size < count) {
10126 if (buf != kbuf)
10127 break;
10128 /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
10129 pr_warn("Line length is too long: Should be less than %d\n",
10130 WRITE_BUFSIZE - 2);
10131 ret = -EINVAL;
10132 goto out;
10133 }
10134 }
10135 done += size;
10136
10137 /* Remove comments */
10138 tmp = strchr(buf, '#');
10139
10140 if (tmp)
10141 *tmp = '\0';
10142
10143 ret = createfn(buf);
10144 if (ret)
10145 goto out;
10146 buf += size;
10147
10148 } while (done < count);
10149 }
10150 ret = done;
10151
10152out:
10153 kfree(kbuf);
10154
10155 return ret;
10156}
10157
10158#ifdef CONFIG_TRACER_MAX_TRACE
10159__init static bool tr_needs_alloc_snapshot(const char *name)
10160{
10161 char *test;
10162 int len = strlen(name);
10163 bool ret;
10164
10165 if (!boot_snapshot_index)
10166 return false;
10167
10168 if (strncmp(name, boot_snapshot_info, len) == 0 &&
10169 boot_snapshot_info[len] == '\t')
10170 return true;
10171
10172 test = kmalloc(strlen(name) + 3, GFP_KERNEL);
10173 if (!test)
10174 return false;
10175
10176 sprintf(test, "\t%s\t", name);
10177 ret = strstr(boot_snapshot_info, test) == NULL;
10178 kfree(test);
10179 return ret;
10180}
10181
10182__init static void do_allocate_snapshot(const char *name)
10183{
10184 if (!tr_needs_alloc_snapshot(name))
10185 return;
10186
10187 /*
10188 * When allocate_snapshot is set, the next call to
10189 * allocate_trace_buffers() (called by trace_array_get_by_name())
10190 * will allocate the snapshot buffer. That will alse clear
10191 * this flag.
10192 */
10193 allocate_snapshot = true;
10194}
10195#else
10196static inline void do_allocate_snapshot(const char *name) { }
10197#endif
10198
10199__init static void enable_instances(void)
10200{
10201 struct trace_array *tr;
10202 char *curr_str;
10203 char *str;
10204 char *tok;
10205
10206 /* A tab is always appended */
10207 boot_instance_info[boot_instance_index - 1] = '\0';
10208 str = boot_instance_info;
10209
10210 while ((curr_str = strsep(&str, "\t"))) {
10211
10212 tok = strsep(&curr_str, ",");
10213
10214 if (IS_ENABLED(CONFIG_TRACER_MAX_TRACE))
10215 do_allocate_snapshot(tok);
10216
10217 tr = trace_array_get_by_name(tok, NULL);
10218 if (!tr) {
10219 pr_warn("Failed to create instance buffer %s\n", curr_str);
10220 continue;
10221 }
10222 /* Allow user space to delete it */
10223 trace_array_put(tr);
10224
10225 while ((tok = strsep(&curr_str, ","))) {
10226 early_enable_events(tr, tok, true);
10227 }
10228 }
10229}
10230
10231__init static int tracer_alloc_buffers(void)
10232{
10233 int ring_buf_size;
10234 int ret = -ENOMEM;
10235
10236
10237 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10238 pr_warn("Tracing disabled due to lockdown\n");
10239 return -EPERM;
10240 }
10241
10242 /*
10243 * Make sure we don't accidentally add more trace options
10244 * than we have bits for.
10245 */
10246 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
10247
10248 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
10249 goto out;
10250
10251 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
10252 goto out_free_buffer_mask;
10253
10254 /* Only allocate trace_printk buffers if a trace_printk exists */
10255 if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
10256 /* Must be called before global_trace.buffer is allocated */
10257 trace_printk_init_buffers();
10258
10259 /* To save memory, keep the ring buffer size to its minimum */
10260 if (global_trace.ring_buffer_expanded)
10261 ring_buf_size = trace_buf_size;
10262 else
10263 ring_buf_size = 1;
10264
10265 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
10266 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
10267
10268 raw_spin_lock_init(&global_trace.start_lock);
10269
10270 /*
10271 * The prepare callbacks allocates some memory for the ring buffer. We
10272 * don't free the buffer if the CPU goes down. If we were to free
10273 * the buffer, then the user would lose any trace that was in the
10274 * buffer. The memory will be removed once the "instance" is removed.
10275 */
10276 ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
10277 "trace/RB:prepare", trace_rb_cpu_prepare,
10278 NULL);
10279 if (ret < 0)
10280 goto out_free_cpumask;
10281 /* Used for event triggers */
10282 ret = -ENOMEM;
10283 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
10284 if (!temp_buffer)
10285 goto out_rm_hp_state;
10286
10287 if (trace_create_savedcmd() < 0)
10288 goto out_free_temp_buffer;
10289
10290 if (!zalloc_cpumask_var(&global_trace.pipe_cpumask, GFP_KERNEL))
10291 goto out_free_savedcmd;
10292
10293 /* TODO: make the number of buffers hot pluggable with CPUS */
10294 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
10295 MEM_FAIL(1, "tracer: failed to allocate ring buffer!\n");
10296 goto out_free_pipe_cpumask;
10297 }
10298 if (global_trace.buffer_disabled)
10299 tracing_off();
10300
10301 if (trace_boot_clock) {
10302 ret = tracing_set_clock(&global_trace, trace_boot_clock);
10303 if (ret < 0)
10304 pr_warn("Trace clock %s not defined, going back to default\n",
10305 trace_boot_clock);
10306 }
10307
10308 /*
10309 * register_tracer() might reference current_trace, so it
10310 * needs to be set before we register anything. This is
10311 * just a bootstrap of current_trace anyway.
10312 */
10313 global_trace.current_trace = &nop_trace;
10314
10315 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
10316#ifdef CONFIG_TRACER_MAX_TRACE
10317 spin_lock_init(&global_trace.snapshot_trigger_lock);
10318#endif
10319 ftrace_init_global_array_ops(&global_trace);
10320
10321 init_trace_flags_index(&global_trace);
10322
10323 register_tracer(&nop_trace);
10324
10325 /* Function tracing may start here (via kernel command line) */
10326 init_function_trace();
10327
10328 /* All seems OK, enable tracing */
10329 tracing_disabled = 0;
10330
10331 atomic_notifier_chain_register(&panic_notifier_list,
10332 &trace_panic_notifier);
10333
10334 register_die_notifier(&trace_die_notifier);
10335
10336 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
10337
10338 INIT_LIST_HEAD(&global_trace.systems);
10339 INIT_LIST_HEAD(&global_trace.events);
10340 INIT_LIST_HEAD(&global_trace.hist_vars);
10341 INIT_LIST_HEAD(&global_trace.err_log);
10342 list_add(&global_trace.list, &ftrace_trace_arrays);
10343
10344 apply_trace_boot_options();
10345
10346 register_snapshot_cmd();
10347
10348 test_can_verify();
10349
10350 return 0;
10351
10352out_free_pipe_cpumask:
10353 free_cpumask_var(global_trace.pipe_cpumask);
10354out_free_savedcmd:
10355 trace_free_saved_cmdlines_buffer();
10356out_free_temp_buffer:
10357 ring_buffer_free(temp_buffer);
10358out_rm_hp_state:
10359 cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
10360out_free_cpumask:
10361 free_cpumask_var(global_trace.tracing_cpumask);
10362out_free_buffer_mask:
10363 free_cpumask_var(tracing_buffer_mask);
10364out:
10365 return ret;
10366}
10367
10368void __init ftrace_boot_snapshot(void)
10369{
10370#ifdef CONFIG_TRACER_MAX_TRACE
10371 struct trace_array *tr;
10372
10373 if (!snapshot_at_boot)
10374 return;
10375
10376 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
10377 if (!tr->allocated_snapshot)
10378 continue;
10379
10380 tracing_snapshot_instance(tr);
10381 trace_array_puts(tr, "** Boot snapshot taken **\n");
10382 }
10383#endif
10384}
10385
10386void __init early_trace_init(void)
10387{
10388 if (tracepoint_printk) {
10389 tracepoint_print_iter =
10390 kzalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
10391 if (MEM_FAIL(!tracepoint_print_iter,
10392 "Failed to allocate trace iterator\n"))
10393 tracepoint_printk = 0;
10394 else
10395 static_key_enable(&tracepoint_printk_key.key);
10396 }
10397 tracer_alloc_buffers();
10398
10399 init_events();
10400}
10401
10402void __init trace_init(void)
10403{
10404 trace_event_init();
10405
10406 if (boot_instance_index)
10407 enable_instances();
10408}
10409
10410__init static void clear_boot_tracer(void)
10411{
10412 /*
10413 * The default tracer at boot buffer is an init section.
10414 * This function is called in lateinit. If we did not
10415 * find the boot tracer, then clear it out, to prevent
10416 * later registration from accessing the buffer that is
10417 * about to be freed.
10418 */
10419 if (!default_bootup_tracer)
10420 return;
10421
10422 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
10423 default_bootup_tracer);
10424 default_bootup_tracer = NULL;
10425}
10426
10427#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
10428__init static void tracing_set_default_clock(void)
10429{
10430 /* sched_clock_stable() is determined in late_initcall */
10431 if (!trace_boot_clock && !sched_clock_stable()) {
10432 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10433 pr_warn("Can not set tracing clock due to lockdown\n");
10434 return;
10435 }
10436
10437 printk(KERN_WARNING
10438 "Unstable clock detected, switching default tracing clock to \"global\"\n"
10439 "If you want to keep using the local clock, then add:\n"
10440 " \"trace_clock=local\"\n"
10441 "on the kernel command line\n");
10442 tracing_set_clock(&global_trace, "global");
10443 }
10444}
10445#else
10446static inline void tracing_set_default_clock(void) { }
10447#endif
10448
10449__init static int late_trace_init(void)
10450{
10451 if (tracepoint_printk && tracepoint_printk_stop_on_boot) {
10452 static_key_disable(&tracepoint_printk_key.key);
10453 tracepoint_printk = 0;
10454 }
10455
10456 tracing_set_default_clock();
10457 clear_boot_tracer();
10458 return 0;
10459}
10460
10461late_initcall_sync(late_trace_init);
1/*
2 * ring buffer based function tracer
3 *
4 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
9 *
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 Nadia Yvette Chambers
13 */
14#include <linux/ring_buffer.h>
15#include <generated/utsrelease.h>
16#include <linux/stacktrace.h>
17#include <linux/writeback.h>
18#include <linux/kallsyms.h>
19#include <linux/seq_file.h>
20#include <linux/notifier.h>
21#include <linux/irqflags.h>
22#include <linux/debugfs.h>
23#include <linux/pagemap.h>
24#include <linux/hardirq.h>
25#include <linux/linkage.h>
26#include <linux/uaccess.h>
27#include <linux/kprobes.h>
28#include <linux/ftrace.h>
29#include <linux/module.h>
30#include <linux/percpu.h>
31#include <linux/splice.h>
32#include <linux/kdebug.h>
33#include <linux/string.h>
34#include <linux/rwsem.h>
35#include <linux/slab.h>
36#include <linux/ctype.h>
37#include <linux/init.h>
38#include <linux/poll.h>
39#include <linux/nmi.h>
40#include <linux/fs.h>
41#include <linux/sched/rt.h>
42
43#include "trace.h"
44#include "trace_output.h"
45
46/*
47 * On boot up, the ring buffer is set to the minimum size, so that
48 * we do not waste memory on systems that are not using tracing.
49 */
50bool ring_buffer_expanded;
51
52/*
53 * We need to change this state when a selftest is running.
54 * A selftest will lurk into the ring-buffer to count the
55 * entries inserted during the selftest although some concurrent
56 * insertions into the ring-buffer such as trace_printk could occurred
57 * at the same time, giving false positive or negative results.
58 */
59static bool __read_mostly tracing_selftest_running;
60
61/*
62 * If a tracer is running, we do not want to run SELFTEST.
63 */
64bool __read_mostly tracing_selftest_disabled;
65
66/* For tracers that don't implement custom flags */
67static struct tracer_opt dummy_tracer_opt[] = {
68 { }
69};
70
71static struct tracer_flags dummy_tracer_flags = {
72 .val = 0,
73 .opts = dummy_tracer_opt
74};
75
76static int
77dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
78{
79 return 0;
80}
81
82/*
83 * To prevent the comm cache from being overwritten when no
84 * tracing is active, only save the comm when a trace event
85 * occurred.
86 */
87static DEFINE_PER_CPU(bool, trace_cmdline_save);
88
89/*
90 * Kill all tracing for good (never come back).
91 * It is initialized to 1 but will turn to zero if the initialization
92 * of the tracer is successful. But that is the only place that sets
93 * this back to zero.
94 */
95static int tracing_disabled = 1;
96
97DEFINE_PER_CPU(int, ftrace_cpu_disabled);
98
99cpumask_var_t __read_mostly tracing_buffer_mask;
100
101/*
102 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
103 *
104 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
105 * is set, then ftrace_dump is called. This will output the contents
106 * of the ftrace buffers to the console. This is very useful for
107 * capturing traces that lead to crashes and outputing it to a
108 * serial console.
109 *
110 * It is default off, but you can enable it with either specifying
111 * "ftrace_dump_on_oops" in the kernel command line, or setting
112 * /proc/sys/kernel/ftrace_dump_on_oops
113 * Set 1 if you want to dump buffers of all CPUs
114 * Set 2 if you want to dump the buffer of the CPU that triggered oops
115 */
116
117enum ftrace_dump_mode ftrace_dump_on_oops;
118
119/* When set, tracing will stop when a WARN*() is hit */
120int __disable_trace_on_warning;
121
122static int tracing_set_tracer(struct trace_array *tr, const char *buf);
123
124#define MAX_TRACER_SIZE 100
125static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
126static char *default_bootup_tracer;
127
128static bool allocate_snapshot;
129
130static int __init set_cmdline_ftrace(char *str)
131{
132 strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
133 default_bootup_tracer = bootup_tracer_buf;
134 /* We are using ftrace early, expand it */
135 ring_buffer_expanded = true;
136 return 1;
137}
138__setup("ftrace=", set_cmdline_ftrace);
139
140static int __init set_ftrace_dump_on_oops(char *str)
141{
142 if (*str++ != '=' || !*str) {
143 ftrace_dump_on_oops = DUMP_ALL;
144 return 1;
145 }
146
147 if (!strcmp("orig_cpu", str)) {
148 ftrace_dump_on_oops = DUMP_ORIG;
149 return 1;
150 }
151
152 return 0;
153}
154__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
155
156static int __init stop_trace_on_warning(char *str)
157{
158 __disable_trace_on_warning = 1;
159 return 1;
160}
161__setup("traceoff_on_warning=", stop_trace_on_warning);
162
163static int __init boot_alloc_snapshot(char *str)
164{
165 allocate_snapshot = true;
166 /* We also need the main ring buffer expanded */
167 ring_buffer_expanded = true;
168 return 1;
169}
170__setup("alloc_snapshot", boot_alloc_snapshot);
171
172
173static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
174static char *trace_boot_options __initdata;
175
176static int __init set_trace_boot_options(char *str)
177{
178 strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
179 trace_boot_options = trace_boot_options_buf;
180 return 0;
181}
182__setup("trace_options=", set_trace_boot_options);
183
184static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
185static char *trace_boot_clock __initdata;
186
187static int __init set_trace_boot_clock(char *str)
188{
189 strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
190 trace_boot_clock = trace_boot_clock_buf;
191 return 0;
192}
193__setup("trace_clock=", set_trace_boot_clock);
194
195
196unsigned long long ns2usecs(cycle_t nsec)
197{
198 nsec += 500;
199 do_div(nsec, 1000);
200 return nsec;
201}
202
203/*
204 * The global_trace is the descriptor that holds the tracing
205 * buffers for the live tracing. For each CPU, it contains
206 * a link list of pages that will store trace entries. The
207 * page descriptor of the pages in the memory is used to hold
208 * the link list by linking the lru item in the page descriptor
209 * to each of the pages in the buffer per CPU.
210 *
211 * For each active CPU there is a data field that holds the
212 * pages for the buffer for that CPU. Each CPU has the same number
213 * of pages allocated for its buffer.
214 */
215static struct trace_array global_trace;
216
217LIST_HEAD(ftrace_trace_arrays);
218
219int trace_array_get(struct trace_array *this_tr)
220{
221 struct trace_array *tr;
222 int ret = -ENODEV;
223
224 mutex_lock(&trace_types_lock);
225 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
226 if (tr == this_tr) {
227 tr->ref++;
228 ret = 0;
229 break;
230 }
231 }
232 mutex_unlock(&trace_types_lock);
233
234 return ret;
235}
236
237static void __trace_array_put(struct trace_array *this_tr)
238{
239 WARN_ON(!this_tr->ref);
240 this_tr->ref--;
241}
242
243void trace_array_put(struct trace_array *this_tr)
244{
245 mutex_lock(&trace_types_lock);
246 __trace_array_put(this_tr);
247 mutex_unlock(&trace_types_lock);
248}
249
250int filter_check_discard(struct ftrace_event_file *file, void *rec,
251 struct ring_buffer *buffer,
252 struct ring_buffer_event *event)
253{
254 if (unlikely(file->flags & FTRACE_EVENT_FL_FILTERED) &&
255 !filter_match_preds(file->filter, rec)) {
256 ring_buffer_discard_commit(buffer, event);
257 return 1;
258 }
259
260 return 0;
261}
262EXPORT_SYMBOL_GPL(filter_check_discard);
263
264int call_filter_check_discard(struct ftrace_event_call *call, void *rec,
265 struct ring_buffer *buffer,
266 struct ring_buffer_event *event)
267{
268 if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
269 !filter_match_preds(call->filter, rec)) {
270 ring_buffer_discard_commit(buffer, event);
271 return 1;
272 }
273
274 return 0;
275}
276EXPORT_SYMBOL_GPL(call_filter_check_discard);
277
278cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu)
279{
280 u64 ts;
281
282 /* Early boot up does not have a buffer yet */
283 if (!buf->buffer)
284 return trace_clock_local();
285
286 ts = ring_buffer_time_stamp(buf->buffer, cpu);
287 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
288
289 return ts;
290}
291
292cycle_t ftrace_now(int cpu)
293{
294 return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
295}
296
297/**
298 * tracing_is_enabled - Show if global_trace has been disabled
299 *
300 * Shows if the global trace has been enabled or not. It uses the
301 * mirror flag "buffer_disabled" to be used in fast paths such as for
302 * the irqsoff tracer. But it may be inaccurate due to races. If you
303 * need to know the accurate state, use tracing_is_on() which is a little
304 * slower, but accurate.
305 */
306int tracing_is_enabled(void)
307{
308 /*
309 * For quick access (irqsoff uses this in fast path), just
310 * return the mirror variable of the state of the ring buffer.
311 * It's a little racy, but we don't really care.
312 */
313 smp_rmb();
314 return !global_trace.buffer_disabled;
315}
316
317/*
318 * trace_buf_size is the size in bytes that is allocated
319 * for a buffer. Note, the number of bytes is always rounded
320 * to page size.
321 *
322 * This number is purposely set to a low number of 16384.
323 * If the dump on oops happens, it will be much appreciated
324 * to not have to wait for all that output. Anyway this can be
325 * boot time and run time configurable.
326 */
327#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
328
329static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
330
331/* trace_types holds a link list of available tracers. */
332static struct tracer *trace_types __read_mostly;
333
334/*
335 * trace_types_lock is used to protect the trace_types list.
336 */
337DEFINE_MUTEX(trace_types_lock);
338
339/*
340 * serialize the access of the ring buffer
341 *
342 * ring buffer serializes readers, but it is low level protection.
343 * The validity of the events (which returns by ring_buffer_peek() ..etc)
344 * are not protected by ring buffer.
345 *
346 * The content of events may become garbage if we allow other process consumes
347 * these events concurrently:
348 * A) the page of the consumed events may become a normal page
349 * (not reader page) in ring buffer, and this page will be rewrited
350 * by events producer.
351 * B) The page of the consumed events may become a page for splice_read,
352 * and this page will be returned to system.
353 *
354 * These primitives allow multi process access to different cpu ring buffer
355 * concurrently.
356 *
357 * These primitives don't distinguish read-only and read-consume access.
358 * Multi read-only access are also serialized.
359 */
360
361#ifdef CONFIG_SMP
362static DECLARE_RWSEM(all_cpu_access_lock);
363static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
364
365static inline void trace_access_lock(int cpu)
366{
367 if (cpu == RING_BUFFER_ALL_CPUS) {
368 /* gain it for accessing the whole ring buffer. */
369 down_write(&all_cpu_access_lock);
370 } else {
371 /* gain it for accessing a cpu ring buffer. */
372
373 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
374 down_read(&all_cpu_access_lock);
375
376 /* Secondly block other access to this @cpu ring buffer. */
377 mutex_lock(&per_cpu(cpu_access_lock, cpu));
378 }
379}
380
381static inline void trace_access_unlock(int cpu)
382{
383 if (cpu == RING_BUFFER_ALL_CPUS) {
384 up_write(&all_cpu_access_lock);
385 } else {
386 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
387 up_read(&all_cpu_access_lock);
388 }
389}
390
391static inline void trace_access_lock_init(void)
392{
393 int cpu;
394
395 for_each_possible_cpu(cpu)
396 mutex_init(&per_cpu(cpu_access_lock, cpu));
397}
398
399#else
400
401static DEFINE_MUTEX(access_lock);
402
403static inline void trace_access_lock(int cpu)
404{
405 (void)cpu;
406 mutex_lock(&access_lock);
407}
408
409static inline void trace_access_unlock(int cpu)
410{
411 (void)cpu;
412 mutex_unlock(&access_lock);
413}
414
415static inline void trace_access_lock_init(void)
416{
417}
418
419#endif
420
421/* trace_flags holds trace_options default values */
422unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
423 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
424 TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE |
425 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | TRACE_ITER_FUNCTION;
426
427static void tracer_tracing_on(struct trace_array *tr)
428{
429 if (tr->trace_buffer.buffer)
430 ring_buffer_record_on(tr->trace_buffer.buffer);
431 /*
432 * This flag is looked at when buffers haven't been allocated
433 * yet, or by some tracers (like irqsoff), that just want to
434 * know if the ring buffer has been disabled, but it can handle
435 * races of where it gets disabled but we still do a record.
436 * As the check is in the fast path of the tracers, it is more
437 * important to be fast than accurate.
438 */
439 tr->buffer_disabled = 0;
440 /* Make the flag seen by readers */
441 smp_wmb();
442}
443
444/**
445 * tracing_on - enable tracing buffers
446 *
447 * This function enables tracing buffers that may have been
448 * disabled with tracing_off.
449 */
450void tracing_on(void)
451{
452 tracer_tracing_on(&global_trace);
453}
454EXPORT_SYMBOL_GPL(tracing_on);
455
456/**
457 * __trace_puts - write a constant string into the trace buffer.
458 * @ip: The address of the caller
459 * @str: The constant string to write
460 * @size: The size of the string.
461 */
462int __trace_puts(unsigned long ip, const char *str, int size)
463{
464 struct ring_buffer_event *event;
465 struct ring_buffer *buffer;
466 struct print_entry *entry;
467 unsigned long irq_flags;
468 int alloc;
469
470 if (unlikely(tracing_selftest_running || tracing_disabled))
471 return 0;
472
473 alloc = sizeof(*entry) + size + 2; /* possible \n added */
474
475 local_save_flags(irq_flags);
476 buffer = global_trace.trace_buffer.buffer;
477 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
478 irq_flags, preempt_count());
479 if (!event)
480 return 0;
481
482 entry = ring_buffer_event_data(event);
483 entry->ip = ip;
484
485 memcpy(&entry->buf, str, size);
486
487 /* Add a newline if necessary */
488 if (entry->buf[size - 1] != '\n') {
489 entry->buf[size] = '\n';
490 entry->buf[size + 1] = '\0';
491 } else
492 entry->buf[size] = '\0';
493
494 __buffer_unlock_commit(buffer, event);
495
496 return size;
497}
498EXPORT_SYMBOL_GPL(__trace_puts);
499
500/**
501 * __trace_bputs - write the pointer to a constant string into trace buffer
502 * @ip: The address of the caller
503 * @str: The constant string to write to the buffer to
504 */
505int __trace_bputs(unsigned long ip, const char *str)
506{
507 struct ring_buffer_event *event;
508 struct ring_buffer *buffer;
509 struct bputs_entry *entry;
510 unsigned long irq_flags;
511 int size = sizeof(struct bputs_entry);
512
513 if (unlikely(tracing_selftest_running || tracing_disabled))
514 return 0;
515
516 local_save_flags(irq_flags);
517 buffer = global_trace.trace_buffer.buffer;
518 event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
519 irq_flags, preempt_count());
520 if (!event)
521 return 0;
522
523 entry = ring_buffer_event_data(event);
524 entry->ip = ip;
525 entry->str = str;
526
527 __buffer_unlock_commit(buffer, event);
528
529 return 1;
530}
531EXPORT_SYMBOL_GPL(__trace_bputs);
532
533#ifdef CONFIG_TRACER_SNAPSHOT
534/**
535 * trace_snapshot - take a snapshot of the current buffer.
536 *
537 * This causes a swap between the snapshot buffer and the current live
538 * tracing buffer. You can use this to take snapshots of the live
539 * trace when some condition is triggered, but continue to trace.
540 *
541 * Note, make sure to allocate the snapshot with either
542 * a tracing_snapshot_alloc(), or by doing it manually
543 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
544 *
545 * If the snapshot buffer is not allocated, it will stop tracing.
546 * Basically making a permanent snapshot.
547 */
548void tracing_snapshot(void)
549{
550 struct trace_array *tr = &global_trace;
551 struct tracer *tracer = tr->current_trace;
552 unsigned long flags;
553
554 if (in_nmi()) {
555 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
556 internal_trace_puts("*** snapshot is being ignored ***\n");
557 return;
558 }
559
560 if (!tr->allocated_snapshot) {
561 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
562 internal_trace_puts("*** stopping trace here! ***\n");
563 tracing_off();
564 return;
565 }
566
567 /* Note, snapshot can not be used when the tracer uses it */
568 if (tracer->use_max_tr) {
569 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
570 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
571 return;
572 }
573
574 local_irq_save(flags);
575 update_max_tr(tr, current, smp_processor_id());
576 local_irq_restore(flags);
577}
578EXPORT_SYMBOL_GPL(tracing_snapshot);
579
580static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
581 struct trace_buffer *size_buf, int cpu_id);
582static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
583
584static int alloc_snapshot(struct trace_array *tr)
585{
586 int ret;
587
588 if (!tr->allocated_snapshot) {
589
590 /* allocate spare buffer */
591 ret = resize_buffer_duplicate_size(&tr->max_buffer,
592 &tr->trace_buffer, RING_BUFFER_ALL_CPUS);
593 if (ret < 0)
594 return ret;
595
596 tr->allocated_snapshot = true;
597 }
598
599 return 0;
600}
601
602void free_snapshot(struct trace_array *tr)
603{
604 /*
605 * We don't free the ring buffer. instead, resize it because
606 * The max_tr ring buffer has some state (e.g. ring->clock) and
607 * we want preserve it.
608 */
609 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
610 set_buffer_entries(&tr->max_buffer, 1);
611 tracing_reset_online_cpus(&tr->max_buffer);
612 tr->allocated_snapshot = false;
613}
614
615/**
616 * tracing_alloc_snapshot - allocate snapshot buffer.
617 *
618 * This only allocates the snapshot buffer if it isn't already
619 * allocated - it doesn't also take a snapshot.
620 *
621 * This is meant to be used in cases where the snapshot buffer needs
622 * to be set up for events that can't sleep but need to be able to
623 * trigger a snapshot.
624 */
625int tracing_alloc_snapshot(void)
626{
627 struct trace_array *tr = &global_trace;
628 int ret;
629
630 ret = alloc_snapshot(tr);
631 WARN_ON(ret < 0);
632
633 return ret;
634}
635EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
636
637/**
638 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
639 *
640 * This is similar to trace_snapshot(), but it will allocate the
641 * snapshot buffer if it isn't already allocated. Use this only
642 * where it is safe to sleep, as the allocation may sleep.
643 *
644 * This causes a swap between the snapshot buffer and the current live
645 * tracing buffer. You can use this to take snapshots of the live
646 * trace when some condition is triggered, but continue to trace.
647 */
648void tracing_snapshot_alloc(void)
649{
650 int ret;
651
652 ret = tracing_alloc_snapshot();
653 if (ret < 0)
654 return;
655
656 tracing_snapshot();
657}
658EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
659#else
660void tracing_snapshot(void)
661{
662 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
663}
664EXPORT_SYMBOL_GPL(tracing_snapshot);
665int tracing_alloc_snapshot(void)
666{
667 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
668 return -ENODEV;
669}
670EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
671void tracing_snapshot_alloc(void)
672{
673 /* Give warning */
674 tracing_snapshot();
675}
676EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
677#endif /* CONFIG_TRACER_SNAPSHOT */
678
679static void tracer_tracing_off(struct trace_array *tr)
680{
681 if (tr->trace_buffer.buffer)
682 ring_buffer_record_off(tr->trace_buffer.buffer);
683 /*
684 * This flag is looked at when buffers haven't been allocated
685 * yet, or by some tracers (like irqsoff), that just want to
686 * know if the ring buffer has been disabled, but it can handle
687 * races of where it gets disabled but we still do a record.
688 * As the check is in the fast path of the tracers, it is more
689 * important to be fast than accurate.
690 */
691 tr->buffer_disabled = 1;
692 /* Make the flag seen by readers */
693 smp_wmb();
694}
695
696/**
697 * tracing_off - turn off tracing buffers
698 *
699 * This function stops the tracing buffers from recording data.
700 * It does not disable any overhead the tracers themselves may
701 * be causing. This function simply causes all recording to
702 * the ring buffers to fail.
703 */
704void tracing_off(void)
705{
706 tracer_tracing_off(&global_trace);
707}
708EXPORT_SYMBOL_GPL(tracing_off);
709
710void disable_trace_on_warning(void)
711{
712 if (__disable_trace_on_warning)
713 tracing_off();
714}
715
716/**
717 * tracer_tracing_is_on - show real state of ring buffer enabled
718 * @tr : the trace array to know if ring buffer is enabled
719 *
720 * Shows real state of the ring buffer if it is enabled or not.
721 */
722static int tracer_tracing_is_on(struct trace_array *tr)
723{
724 if (tr->trace_buffer.buffer)
725 return ring_buffer_record_is_on(tr->trace_buffer.buffer);
726 return !tr->buffer_disabled;
727}
728
729/**
730 * tracing_is_on - show state of ring buffers enabled
731 */
732int tracing_is_on(void)
733{
734 return tracer_tracing_is_on(&global_trace);
735}
736EXPORT_SYMBOL_GPL(tracing_is_on);
737
738static int __init set_buf_size(char *str)
739{
740 unsigned long buf_size;
741
742 if (!str)
743 return 0;
744 buf_size = memparse(str, &str);
745 /* nr_entries can not be zero */
746 if (buf_size == 0)
747 return 0;
748 trace_buf_size = buf_size;
749 return 1;
750}
751__setup("trace_buf_size=", set_buf_size);
752
753static int __init set_tracing_thresh(char *str)
754{
755 unsigned long threshold;
756 int ret;
757
758 if (!str)
759 return 0;
760 ret = kstrtoul(str, 0, &threshold);
761 if (ret < 0)
762 return 0;
763 tracing_thresh = threshold * 1000;
764 return 1;
765}
766__setup("tracing_thresh=", set_tracing_thresh);
767
768unsigned long nsecs_to_usecs(unsigned long nsecs)
769{
770 return nsecs / 1000;
771}
772
773/* These must match the bit postions in trace_iterator_flags */
774static const char *trace_options[] = {
775 "print-parent",
776 "sym-offset",
777 "sym-addr",
778 "verbose",
779 "raw",
780 "hex",
781 "bin",
782 "block",
783 "stacktrace",
784 "trace_printk",
785 "ftrace_preempt",
786 "branch",
787 "annotate",
788 "userstacktrace",
789 "sym-userobj",
790 "printk-msg-only",
791 "context-info",
792 "latency-format",
793 "sleep-time",
794 "graph-time",
795 "record-cmd",
796 "overwrite",
797 "disable_on_free",
798 "irq-info",
799 "markers",
800 "function-trace",
801 NULL
802};
803
804static struct {
805 u64 (*func)(void);
806 const char *name;
807 int in_ns; /* is this clock in nanoseconds? */
808} trace_clocks[] = {
809 { trace_clock_local, "local", 1 },
810 { trace_clock_global, "global", 1 },
811 { trace_clock_counter, "counter", 0 },
812 { trace_clock_jiffies, "uptime", 1 },
813 { trace_clock, "perf", 1 },
814 ARCH_TRACE_CLOCKS
815};
816
817/*
818 * trace_parser_get_init - gets the buffer for trace parser
819 */
820int trace_parser_get_init(struct trace_parser *parser, int size)
821{
822 memset(parser, 0, sizeof(*parser));
823
824 parser->buffer = kmalloc(size, GFP_KERNEL);
825 if (!parser->buffer)
826 return 1;
827
828 parser->size = size;
829 return 0;
830}
831
832/*
833 * trace_parser_put - frees the buffer for trace parser
834 */
835void trace_parser_put(struct trace_parser *parser)
836{
837 kfree(parser->buffer);
838}
839
840/*
841 * trace_get_user - reads the user input string separated by space
842 * (matched by isspace(ch))
843 *
844 * For each string found the 'struct trace_parser' is updated,
845 * and the function returns.
846 *
847 * Returns number of bytes read.
848 *
849 * See kernel/trace/trace.h for 'struct trace_parser' details.
850 */
851int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
852 size_t cnt, loff_t *ppos)
853{
854 char ch;
855 size_t read = 0;
856 ssize_t ret;
857
858 if (!*ppos)
859 trace_parser_clear(parser);
860
861 ret = get_user(ch, ubuf++);
862 if (ret)
863 goto out;
864
865 read++;
866 cnt--;
867
868 /*
869 * The parser is not finished with the last write,
870 * continue reading the user input without skipping spaces.
871 */
872 if (!parser->cont) {
873 /* skip white space */
874 while (cnt && isspace(ch)) {
875 ret = get_user(ch, ubuf++);
876 if (ret)
877 goto out;
878 read++;
879 cnt--;
880 }
881
882 /* only spaces were written */
883 if (isspace(ch)) {
884 *ppos += read;
885 ret = read;
886 goto out;
887 }
888
889 parser->idx = 0;
890 }
891
892 /* read the non-space input */
893 while (cnt && !isspace(ch)) {
894 if (parser->idx < parser->size - 1)
895 parser->buffer[parser->idx++] = ch;
896 else {
897 ret = -EINVAL;
898 goto out;
899 }
900 ret = get_user(ch, ubuf++);
901 if (ret)
902 goto out;
903 read++;
904 cnt--;
905 }
906
907 /* We either got finished input or we have to wait for another call. */
908 if (isspace(ch)) {
909 parser->buffer[parser->idx] = 0;
910 parser->cont = false;
911 } else if (parser->idx < parser->size - 1) {
912 parser->cont = true;
913 parser->buffer[parser->idx++] = ch;
914 } else {
915 ret = -EINVAL;
916 goto out;
917 }
918
919 *ppos += read;
920 ret = read;
921
922out:
923 return ret;
924}
925
926ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
927{
928 int len;
929 int ret;
930
931 if (!cnt)
932 return 0;
933
934 if (s->len <= s->readpos)
935 return -EBUSY;
936
937 len = s->len - s->readpos;
938 if (cnt > len)
939 cnt = len;
940 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
941 if (ret == cnt)
942 return -EFAULT;
943
944 cnt -= ret;
945
946 s->readpos += cnt;
947 return cnt;
948}
949
950static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
951{
952 int len;
953
954 if (s->len <= s->readpos)
955 return -EBUSY;
956
957 len = s->len - s->readpos;
958 if (cnt > len)
959 cnt = len;
960 memcpy(buf, s->buffer + s->readpos, cnt);
961
962 s->readpos += cnt;
963 return cnt;
964}
965
966/*
967 * ftrace_max_lock is used to protect the swapping of buffers
968 * when taking a max snapshot. The buffers themselves are
969 * protected by per_cpu spinlocks. But the action of the swap
970 * needs its own lock.
971 *
972 * This is defined as a arch_spinlock_t in order to help
973 * with performance when lockdep debugging is enabled.
974 *
975 * It is also used in other places outside the update_max_tr
976 * so it needs to be defined outside of the
977 * CONFIG_TRACER_MAX_TRACE.
978 */
979static arch_spinlock_t ftrace_max_lock =
980 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
981
982unsigned long __read_mostly tracing_thresh;
983
984#ifdef CONFIG_TRACER_MAX_TRACE
985unsigned long __read_mostly tracing_max_latency;
986
987/*
988 * Copy the new maximum trace into the separate maximum-trace
989 * structure. (this way the maximum trace is permanently saved,
990 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
991 */
992static void
993__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
994{
995 struct trace_buffer *trace_buf = &tr->trace_buffer;
996 struct trace_buffer *max_buf = &tr->max_buffer;
997 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
998 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
999
1000 max_buf->cpu = cpu;
1001 max_buf->time_start = data->preempt_timestamp;
1002
1003 max_data->saved_latency = tracing_max_latency;
1004 max_data->critical_start = data->critical_start;
1005 max_data->critical_end = data->critical_end;
1006
1007 memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1008 max_data->pid = tsk->pid;
1009 /*
1010 * If tsk == current, then use current_uid(), as that does not use
1011 * RCU. The irq tracer can be called out of RCU scope.
1012 */
1013 if (tsk == current)
1014 max_data->uid = current_uid();
1015 else
1016 max_data->uid = task_uid(tsk);
1017
1018 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1019 max_data->policy = tsk->policy;
1020 max_data->rt_priority = tsk->rt_priority;
1021
1022 /* record this tasks comm */
1023 tracing_record_cmdline(tsk);
1024}
1025
1026/**
1027 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1028 * @tr: tracer
1029 * @tsk: the task with the latency
1030 * @cpu: The cpu that initiated the trace.
1031 *
1032 * Flip the buffers between the @tr and the max_tr and record information
1033 * about which task was the cause of this latency.
1034 */
1035void
1036update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1037{
1038 struct ring_buffer *buf;
1039
1040 if (tr->stop_count)
1041 return;
1042
1043 WARN_ON_ONCE(!irqs_disabled());
1044
1045 if (!tr->allocated_snapshot) {
1046 /* Only the nop tracer should hit this when disabling */
1047 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1048 return;
1049 }
1050
1051 arch_spin_lock(&ftrace_max_lock);
1052
1053 buf = tr->trace_buffer.buffer;
1054 tr->trace_buffer.buffer = tr->max_buffer.buffer;
1055 tr->max_buffer.buffer = buf;
1056
1057 __update_max_tr(tr, tsk, cpu);
1058 arch_spin_unlock(&ftrace_max_lock);
1059}
1060
1061/**
1062 * update_max_tr_single - only copy one trace over, and reset the rest
1063 * @tr - tracer
1064 * @tsk - task with the latency
1065 * @cpu - the cpu of the buffer to copy.
1066 *
1067 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1068 */
1069void
1070update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1071{
1072 int ret;
1073
1074 if (tr->stop_count)
1075 return;
1076
1077 WARN_ON_ONCE(!irqs_disabled());
1078 if (!tr->allocated_snapshot) {
1079 /* Only the nop tracer should hit this when disabling */
1080 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1081 return;
1082 }
1083
1084 arch_spin_lock(&ftrace_max_lock);
1085
1086 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
1087
1088 if (ret == -EBUSY) {
1089 /*
1090 * We failed to swap the buffer due to a commit taking
1091 * place on this CPU. We fail to record, but we reset
1092 * the max trace buffer (no one writes directly to it)
1093 * and flag that it failed.
1094 */
1095 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1096 "Failed to swap buffers due to commit in progress\n");
1097 }
1098
1099 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1100
1101 __update_max_tr(tr, tsk, cpu);
1102 arch_spin_unlock(&ftrace_max_lock);
1103}
1104#endif /* CONFIG_TRACER_MAX_TRACE */
1105
1106static void default_wait_pipe(struct trace_iterator *iter)
1107{
1108 /* Iterators are static, they should be filled or empty */
1109 if (trace_buffer_iter(iter, iter->cpu_file))
1110 return;
1111
1112 ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file);
1113}
1114
1115#ifdef CONFIG_FTRACE_STARTUP_TEST
1116static int run_tracer_selftest(struct tracer *type)
1117{
1118 struct trace_array *tr = &global_trace;
1119 struct tracer *saved_tracer = tr->current_trace;
1120 int ret;
1121
1122 if (!type->selftest || tracing_selftest_disabled)
1123 return 0;
1124
1125 /*
1126 * Run a selftest on this tracer.
1127 * Here we reset the trace buffer, and set the current
1128 * tracer to be this tracer. The tracer can then run some
1129 * internal tracing to verify that everything is in order.
1130 * If we fail, we do not register this tracer.
1131 */
1132 tracing_reset_online_cpus(&tr->trace_buffer);
1133
1134 tr->current_trace = type;
1135
1136#ifdef CONFIG_TRACER_MAX_TRACE
1137 if (type->use_max_tr) {
1138 /* If we expanded the buffers, make sure the max is expanded too */
1139 if (ring_buffer_expanded)
1140 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
1141 RING_BUFFER_ALL_CPUS);
1142 tr->allocated_snapshot = true;
1143 }
1144#endif
1145
1146 /* the test is responsible for initializing and enabling */
1147 pr_info("Testing tracer %s: ", type->name);
1148 ret = type->selftest(type, tr);
1149 /* the test is responsible for resetting too */
1150 tr->current_trace = saved_tracer;
1151 if (ret) {
1152 printk(KERN_CONT "FAILED!\n");
1153 /* Add the warning after printing 'FAILED' */
1154 WARN_ON(1);
1155 return -1;
1156 }
1157 /* Only reset on passing, to avoid touching corrupted buffers */
1158 tracing_reset_online_cpus(&tr->trace_buffer);
1159
1160#ifdef CONFIG_TRACER_MAX_TRACE
1161 if (type->use_max_tr) {
1162 tr->allocated_snapshot = false;
1163
1164 /* Shrink the max buffer again */
1165 if (ring_buffer_expanded)
1166 ring_buffer_resize(tr->max_buffer.buffer, 1,
1167 RING_BUFFER_ALL_CPUS);
1168 }
1169#endif
1170
1171 printk(KERN_CONT "PASSED\n");
1172 return 0;
1173}
1174#else
1175static inline int run_tracer_selftest(struct tracer *type)
1176{
1177 return 0;
1178}
1179#endif /* CONFIG_FTRACE_STARTUP_TEST */
1180
1181/**
1182 * register_tracer - register a tracer with the ftrace system.
1183 * @type - the plugin for the tracer
1184 *
1185 * Register a new plugin tracer.
1186 */
1187int register_tracer(struct tracer *type)
1188{
1189 struct tracer *t;
1190 int ret = 0;
1191
1192 if (!type->name) {
1193 pr_info("Tracer must have a name\n");
1194 return -1;
1195 }
1196
1197 if (strlen(type->name) >= MAX_TRACER_SIZE) {
1198 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
1199 return -1;
1200 }
1201
1202 mutex_lock(&trace_types_lock);
1203
1204 tracing_selftest_running = true;
1205
1206 for (t = trace_types; t; t = t->next) {
1207 if (strcmp(type->name, t->name) == 0) {
1208 /* already found */
1209 pr_info("Tracer %s already registered\n",
1210 type->name);
1211 ret = -1;
1212 goto out;
1213 }
1214 }
1215
1216 if (!type->set_flag)
1217 type->set_flag = &dummy_set_flag;
1218 if (!type->flags)
1219 type->flags = &dummy_tracer_flags;
1220 else
1221 if (!type->flags->opts)
1222 type->flags->opts = dummy_tracer_opt;
1223 if (!type->wait_pipe)
1224 type->wait_pipe = default_wait_pipe;
1225
1226 ret = run_tracer_selftest(type);
1227 if (ret < 0)
1228 goto out;
1229
1230 type->next = trace_types;
1231 trace_types = type;
1232
1233 out:
1234 tracing_selftest_running = false;
1235 mutex_unlock(&trace_types_lock);
1236
1237 if (ret || !default_bootup_tracer)
1238 goto out_unlock;
1239
1240 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
1241 goto out_unlock;
1242
1243 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
1244 /* Do we want this tracer to start on bootup? */
1245 tracing_set_tracer(&global_trace, type->name);
1246 default_bootup_tracer = NULL;
1247 /* disable other selftests, since this will break it. */
1248 tracing_selftest_disabled = true;
1249#ifdef CONFIG_FTRACE_STARTUP_TEST
1250 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
1251 type->name);
1252#endif
1253
1254 out_unlock:
1255 return ret;
1256}
1257
1258void tracing_reset(struct trace_buffer *buf, int cpu)
1259{
1260 struct ring_buffer *buffer = buf->buffer;
1261
1262 if (!buffer)
1263 return;
1264
1265 ring_buffer_record_disable(buffer);
1266
1267 /* Make sure all commits have finished */
1268 synchronize_sched();
1269 ring_buffer_reset_cpu(buffer, cpu);
1270
1271 ring_buffer_record_enable(buffer);
1272}
1273
1274void tracing_reset_online_cpus(struct trace_buffer *buf)
1275{
1276 struct ring_buffer *buffer = buf->buffer;
1277 int cpu;
1278
1279 if (!buffer)
1280 return;
1281
1282 ring_buffer_record_disable(buffer);
1283
1284 /* Make sure all commits have finished */
1285 synchronize_sched();
1286
1287 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
1288
1289 for_each_online_cpu(cpu)
1290 ring_buffer_reset_cpu(buffer, cpu);
1291
1292 ring_buffer_record_enable(buffer);
1293}
1294
1295/* Must have trace_types_lock held */
1296void tracing_reset_all_online_cpus(void)
1297{
1298 struct trace_array *tr;
1299
1300 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1301 tracing_reset_online_cpus(&tr->trace_buffer);
1302#ifdef CONFIG_TRACER_MAX_TRACE
1303 tracing_reset_online_cpus(&tr->max_buffer);
1304#endif
1305 }
1306}
1307
1308#define SAVED_CMDLINES 128
1309#define NO_CMDLINE_MAP UINT_MAX
1310static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
1311static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
1312static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
1313static int cmdline_idx;
1314static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1315
1316/* temporary disable recording */
1317static atomic_t trace_record_cmdline_disabled __read_mostly;
1318
1319static void trace_init_cmdlines(void)
1320{
1321 memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline));
1322 memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid));
1323 cmdline_idx = 0;
1324}
1325
1326int is_tracing_stopped(void)
1327{
1328 return global_trace.stop_count;
1329}
1330
1331/**
1332 * tracing_start - quick start of the tracer
1333 *
1334 * If tracing is enabled but was stopped by tracing_stop,
1335 * this will start the tracer back up.
1336 */
1337void tracing_start(void)
1338{
1339 struct ring_buffer *buffer;
1340 unsigned long flags;
1341
1342 if (tracing_disabled)
1343 return;
1344
1345 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1346 if (--global_trace.stop_count) {
1347 if (global_trace.stop_count < 0) {
1348 /* Someone screwed up their debugging */
1349 WARN_ON_ONCE(1);
1350 global_trace.stop_count = 0;
1351 }
1352 goto out;
1353 }
1354
1355 /* Prevent the buffers from switching */
1356 arch_spin_lock(&ftrace_max_lock);
1357
1358 buffer = global_trace.trace_buffer.buffer;
1359 if (buffer)
1360 ring_buffer_record_enable(buffer);
1361
1362#ifdef CONFIG_TRACER_MAX_TRACE
1363 buffer = global_trace.max_buffer.buffer;
1364 if (buffer)
1365 ring_buffer_record_enable(buffer);
1366#endif
1367
1368 arch_spin_unlock(&ftrace_max_lock);
1369
1370 ftrace_start();
1371 out:
1372 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1373}
1374
1375static void tracing_start_tr(struct trace_array *tr)
1376{
1377 struct ring_buffer *buffer;
1378 unsigned long flags;
1379
1380 if (tracing_disabled)
1381 return;
1382
1383 /* If global, we need to also start the max tracer */
1384 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1385 return tracing_start();
1386
1387 raw_spin_lock_irqsave(&tr->start_lock, flags);
1388
1389 if (--tr->stop_count) {
1390 if (tr->stop_count < 0) {
1391 /* Someone screwed up their debugging */
1392 WARN_ON_ONCE(1);
1393 tr->stop_count = 0;
1394 }
1395 goto out;
1396 }
1397
1398 buffer = tr->trace_buffer.buffer;
1399 if (buffer)
1400 ring_buffer_record_enable(buffer);
1401
1402 out:
1403 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1404}
1405
1406/**
1407 * tracing_stop - quick stop of the tracer
1408 *
1409 * Light weight way to stop tracing. Use in conjunction with
1410 * tracing_start.
1411 */
1412void tracing_stop(void)
1413{
1414 struct ring_buffer *buffer;
1415 unsigned long flags;
1416
1417 ftrace_stop();
1418 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1419 if (global_trace.stop_count++)
1420 goto out;
1421
1422 /* Prevent the buffers from switching */
1423 arch_spin_lock(&ftrace_max_lock);
1424
1425 buffer = global_trace.trace_buffer.buffer;
1426 if (buffer)
1427 ring_buffer_record_disable(buffer);
1428
1429#ifdef CONFIG_TRACER_MAX_TRACE
1430 buffer = global_trace.max_buffer.buffer;
1431 if (buffer)
1432 ring_buffer_record_disable(buffer);
1433#endif
1434
1435 arch_spin_unlock(&ftrace_max_lock);
1436
1437 out:
1438 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1439}
1440
1441static void tracing_stop_tr(struct trace_array *tr)
1442{
1443 struct ring_buffer *buffer;
1444 unsigned long flags;
1445
1446 /* If global, we need to also stop the max tracer */
1447 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1448 return tracing_stop();
1449
1450 raw_spin_lock_irqsave(&tr->start_lock, flags);
1451 if (tr->stop_count++)
1452 goto out;
1453
1454 buffer = tr->trace_buffer.buffer;
1455 if (buffer)
1456 ring_buffer_record_disable(buffer);
1457
1458 out:
1459 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1460}
1461
1462void trace_stop_cmdline_recording(void);
1463
1464static void trace_save_cmdline(struct task_struct *tsk)
1465{
1466 unsigned pid, idx;
1467
1468 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
1469 return;
1470
1471 /*
1472 * It's not the end of the world if we don't get
1473 * the lock, but we also don't want to spin
1474 * nor do we want to disable interrupts,
1475 * so if we miss here, then better luck next time.
1476 */
1477 if (!arch_spin_trylock(&trace_cmdline_lock))
1478 return;
1479
1480 idx = map_pid_to_cmdline[tsk->pid];
1481 if (idx == NO_CMDLINE_MAP) {
1482 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
1483
1484 /*
1485 * Check whether the cmdline buffer at idx has a pid
1486 * mapped. We are going to overwrite that entry so we
1487 * need to clear the map_pid_to_cmdline. Otherwise we
1488 * would read the new comm for the old pid.
1489 */
1490 pid = map_cmdline_to_pid[idx];
1491 if (pid != NO_CMDLINE_MAP)
1492 map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
1493
1494 map_cmdline_to_pid[idx] = tsk->pid;
1495 map_pid_to_cmdline[tsk->pid] = idx;
1496
1497 cmdline_idx = idx;
1498 }
1499
1500 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
1501
1502 arch_spin_unlock(&trace_cmdline_lock);
1503}
1504
1505void trace_find_cmdline(int pid, char comm[])
1506{
1507 unsigned map;
1508
1509 if (!pid) {
1510 strcpy(comm, "<idle>");
1511 return;
1512 }
1513
1514 if (WARN_ON_ONCE(pid < 0)) {
1515 strcpy(comm, "<XXX>");
1516 return;
1517 }
1518
1519 if (pid > PID_MAX_DEFAULT) {
1520 strcpy(comm, "<...>");
1521 return;
1522 }
1523
1524 preempt_disable();
1525 arch_spin_lock(&trace_cmdline_lock);
1526 map = map_pid_to_cmdline[pid];
1527 if (map != NO_CMDLINE_MAP)
1528 strcpy(comm, saved_cmdlines[map]);
1529 else
1530 strcpy(comm, "<...>");
1531
1532 arch_spin_unlock(&trace_cmdline_lock);
1533 preempt_enable();
1534}
1535
1536void tracing_record_cmdline(struct task_struct *tsk)
1537{
1538 if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
1539 return;
1540
1541 if (!__this_cpu_read(trace_cmdline_save))
1542 return;
1543
1544 __this_cpu_write(trace_cmdline_save, false);
1545
1546 trace_save_cmdline(tsk);
1547}
1548
1549void
1550tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
1551 int pc)
1552{
1553 struct task_struct *tsk = current;
1554
1555 entry->preempt_count = pc & 0xff;
1556 entry->pid = (tsk) ? tsk->pid : 0;
1557 entry->flags =
1558#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1559 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
1560#else
1561 TRACE_FLAG_IRQS_NOSUPPORT |
1562#endif
1563 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
1564 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
1565 (tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
1566 (test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
1567}
1568EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
1569
1570struct ring_buffer_event *
1571trace_buffer_lock_reserve(struct ring_buffer *buffer,
1572 int type,
1573 unsigned long len,
1574 unsigned long flags, int pc)
1575{
1576 struct ring_buffer_event *event;
1577
1578 event = ring_buffer_lock_reserve(buffer, len);
1579 if (event != NULL) {
1580 struct trace_entry *ent = ring_buffer_event_data(event);
1581
1582 tracing_generic_entry_update(ent, flags, pc);
1583 ent->type = type;
1584 }
1585
1586 return event;
1587}
1588
1589void
1590__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
1591{
1592 __this_cpu_write(trace_cmdline_save, true);
1593 ring_buffer_unlock_commit(buffer, event);
1594}
1595
1596static inline void
1597__trace_buffer_unlock_commit(struct ring_buffer *buffer,
1598 struct ring_buffer_event *event,
1599 unsigned long flags, int pc)
1600{
1601 __buffer_unlock_commit(buffer, event);
1602
1603 ftrace_trace_stack(buffer, flags, 6, pc);
1604 ftrace_trace_userstack(buffer, flags, pc);
1605}
1606
1607void trace_buffer_unlock_commit(struct ring_buffer *buffer,
1608 struct ring_buffer_event *event,
1609 unsigned long flags, int pc)
1610{
1611 __trace_buffer_unlock_commit(buffer, event, flags, pc);
1612}
1613EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit);
1614
1615static struct ring_buffer *temp_buffer;
1616
1617struct ring_buffer_event *
1618trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
1619 struct ftrace_event_file *ftrace_file,
1620 int type, unsigned long len,
1621 unsigned long flags, int pc)
1622{
1623 struct ring_buffer_event *entry;
1624
1625 *current_rb = ftrace_file->tr->trace_buffer.buffer;
1626 entry = trace_buffer_lock_reserve(*current_rb,
1627 type, len, flags, pc);
1628 /*
1629 * If tracing is off, but we have triggers enabled
1630 * we still need to look at the event data. Use the temp_buffer
1631 * to store the trace event for the tigger to use. It's recusive
1632 * safe and will not be recorded anywhere.
1633 */
1634 if (!entry && ftrace_file->flags & FTRACE_EVENT_FL_TRIGGER_COND) {
1635 *current_rb = temp_buffer;
1636 entry = trace_buffer_lock_reserve(*current_rb,
1637 type, len, flags, pc);
1638 }
1639 return entry;
1640}
1641EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
1642
1643struct ring_buffer_event *
1644trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
1645 int type, unsigned long len,
1646 unsigned long flags, int pc)
1647{
1648 *current_rb = global_trace.trace_buffer.buffer;
1649 return trace_buffer_lock_reserve(*current_rb,
1650 type, len, flags, pc);
1651}
1652EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
1653
1654void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
1655 struct ring_buffer_event *event,
1656 unsigned long flags, int pc)
1657{
1658 __trace_buffer_unlock_commit(buffer, event, flags, pc);
1659}
1660EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
1661
1662void trace_buffer_unlock_commit_regs(struct ring_buffer *buffer,
1663 struct ring_buffer_event *event,
1664 unsigned long flags, int pc,
1665 struct pt_regs *regs)
1666{
1667 __buffer_unlock_commit(buffer, event);
1668
1669 ftrace_trace_stack_regs(buffer, flags, 0, pc, regs);
1670 ftrace_trace_userstack(buffer, flags, pc);
1671}
1672EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs);
1673
1674void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
1675 struct ring_buffer_event *event)
1676{
1677 ring_buffer_discard_commit(buffer, event);
1678}
1679EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
1680
1681void
1682trace_function(struct trace_array *tr,
1683 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1684 int pc)
1685{
1686 struct ftrace_event_call *call = &event_function;
1687 struct ring_buffer *buffer = tr->trace_buffer.buffer;
1688 struct ring_buffer_event *event;
1689 struct ftrace_entry *entry;
1690
1691 /* If we are reading the ring buffer, don't trace */
1692 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
1693 return;
1694
1695 event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
1696 flags, pc);
1697 if (!event)
1698 return;
1699 entry = ring_buffer_event_data(event);
1700 entry->ip = ip;
1701 entry->parent_ip = parent_ip;
1702
1703 if (!call_filter_check_discard(call, entry, buffer, event))
1704 __buffer_unlock_commit(buffer, event);
1705}
1706
1707#ifdef CONFIG_STACKTRACE
1708
1709#define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1710struct ftrace_stack {
1711 unsigned long calls[FTRACE_STACK_MAX_ENTRIES];
1712};
1713
1714static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
1715static DEFINE_PER_CPU(int, ftrace_stack_reserve);
1716
1717static void __ftrace_trace_stack(struct ring_buffer *buffer,
1718 unsigned long flags,
1719 int skip, int pc, struct pt_regs *regs)
1720{
1721 struct ftrace_event_call *call = &event_kernel_stack;
1722 struct ring_buffer_event *event;
1723 struct stack_entry *entry;
1724 struct stack_trace trace;
1725 int use_stack;
1726 int size = FTRACE_STACK_ENTRIES;
1727
1728 trace.nr_entries = 0;
1729 trace.skip = skip;
1730
1731 /*
1732 * Since events can happen in NMIs there's no safe way to
1733 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1734 * or NMI comes in, it will just have to use the default
1735 * FTRACE_STACK_SIZE.
1736 */
1737 preempt_disable_notrace();
1738
1739 use_stack = __this_cpu_inc_return(ftrace_stack_reserve);
1740 /*
1741 * We don't need any atomic variables, just a barrier.
1742 * If an interrupt comes in, we don't care, because it would
1743 * have exited and put the counter back to what we want.
1744 * We just need a barrier to keep gcc from moving things
1745 * around.
1746 */
1747 barrier();
1748 if (use_stack == 1) {
1749 trace.entries = &__get_cpu_var(ftrace_stack).calls[0];
1750 trace.max_entries = FTRACE_STACK_MAX_ENTRIES;
1751
1752 if (regs)
1753 save_stack_trace_regs(regs, &trace);
1754 else
1755 save_stack_trace(&trace);
1756
1757 if (trace.nr_entries > size)
1758 size = trace.nr_entries;
1759 } else
1760 /* From now on, use_stack is a boolean */
1761 use_stack = 0;
1762
1763 size *= sizeof(unsigned long);
1764
1765 event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
1766 sizeof(*entry) + size, flags, pc);
1767 if (!event)
1768 goto out;
1769 entry = ring_buffer_event_data(event);
1770
1771 memset(&entry->caller, 0, size);
1772
1773 if (use_stack)
1774 memcpy(&entry->caller, trace.entries,
1775 trace.nr_entries * sizeof(unsigned long));
1776 else {
1777 trace.max_entries = FTRACE_STACK_ENTRIES;
1778 trace.entries = entry->caller;
1779 if (regs)
1780 save_stack_trace_regs(regs, &trace);
1781 else
1782 save_stack_trace(&trace);
1783 }
1784
1785 entry->size = trace.nr_entries;
1786
1787 if (!call_filter_check_discard(call, entry, buffer, event))
1788 __buffer_unlock_commit(buffer, event);
1789
1790 out:
1791 /* Again, don't let gcc optimize things here */
1792 barrier();
1793 __this_cpu_dec(ftrace_stack_reserve);
1794 preempt_enable_notrace();
1795
1796}
1797
1798void ftrace_trace_stack_regs(struct ring_buffer *buffer, unsigned long flags,
1799 int skip, int pc, struct pt_regs *regs)
1800{
1801 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1802 return;
1803
1804 __ftrace_trace_stack(buffer, flags, skip, pc, regs);
1805}
1806
1807void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
1808 int skip, int pc)
1809{
1810 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1811 return;
1812
1813 __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
1814}
1815
1816void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
1817 int pc)
1818{
1819 __ftrace_trace_stack(tr->trace_buffer.buffer, flags, skip, pc, NULL);
1820}
1821
1822/**
1823 * trace_dump_stack - record a stack back trace in the trace buffer
1824 * @skip: Number of functions to skip (helper handlers)
1825 */
1826void trace_dump_stack(int skip)
1827{
1828 unsigned long flags;
1829
1830 if (tracing_disabled || tracing_selftest_running)
1831 return;
1832
1833 local_save_flags(flags);
1834
1835 /*
1836 * Skip 3 more, seems to get us at the caller of
1837 * this function.
1838 */
1839 skip += 3;
1840 __ftrace_trace_stack(global_trace.trace_buffer.buffer,
1841 flags, skip, preempt_count(), NULL);
1842}
1843
1844static DEFINE_PER_CPU(int, user_stack_count);
1845
1846void
1847ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
1848{
1849 struct ftrace_event_call *call = &event_user_stack;
1850 struct ring_buffer_event *event;
1851 struct userstack_entry *entry;
1852 struct stack_trace trace;
1853
1854 if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
1855 return;
1856
1857 /*
1858 * NMIs can not handle page faults, even with fix ups.
1859 * The save user stack can (and often does) fault.
1860 */
1861 if (unlikely(in_nmi()))
1862 return;
1863
1864 /*
1865 * prevent recursion, since the user stack tracing may
1866 * trigger other kernel events.
1867 */
1868 preempt_disable();
1869 if (__this_cpu_read(user_stack_count))
1870 goto out;
1871
1872 __this_cpu_inc(user_stack_count);
1873
1874 event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
1875 sizeof(*entry), flags, pc);
1876 if (!event)
1877 goto out_drop_count;
1878 entry = ring_buffer_event_data(event);
1879
1880 entry->tgid = current->tgid;
1881 memset(&entry->caller, 0, sizeof(entry->caller));
1882
1883 trace.nr_entries = 0;
1884 trace.max_entries = FTRACE_STACK_ENTRIES;
1885 trace.skip = 0;
1886 trace.entries = entry->caller;
1887
1888 save_stack_trace_user(&trace);
1889 if (!call_filter_check_discard(call, entry, buffer, event))
1890 __buffer_unlock_commit(buffer, event);
1891
1892 out_drop_count:
1893 __this_cpu_dec(user_stack_count);
1894 out:
1895 preempt_enable();
1896}
1897
1898#ifdef UNUSED
1899static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1900{
1901 ftrace_trace_userstack(tr, flags, preempt_count());
1902}
1903#endif /* UNUSED */
1904
1905#endif /* CONFIG_STACKTRACE */
1906
1907/* created for use with alloc_percpu */
1908struct trace_buffer_struct {
1909 char buffer[TRACE_BUF_SIZE];
1910};
1911
1912static struct trace_buffer_struct *trace_percpu_buffer;
1913static struct trace_buffer_struct *trace_percpu_sirq_buffer;
1914static struct trace_buffer_struct *trace_percpu_irq_buffer;
1915static struct trace_buffer_struct *trace_percpu_nmi_buffer;
1916
1917/*
1918 * The buffer used is dependent on the context. There is a per cpu
1919 * buffer for normal context, softirq contex, hard irq context and
1920 * for NMI context. Thise allows for lockless recording.
1921 *
1922 * Note, if the buffers failed to be allocated, then this returns NULL
1923 */
1924static char *get_trace_buf(void)
1925{
1926 struct trace_buffer_struct *percpu_buffer;
1927
1928 /*
1929 * If we have allocated per cpu buffers, then we do not
1930 * need to do any locking.
1931 */
1932 if (in_nmi())
1933 percpu_buffer = trace_percpu_nmi_buffer;
1934 else if (in_irq())
1935 percpu_buffer = trace_percpu_irq_buffer;
1936 else if (in_softirq())
1937 percpu_buffer = trace_percpu_sirq_buffer;
1938 else
1939 percpu_buffer = trace_percpu_buffer;
1940
1941 if (!percpu_buffer)
1942 return NULL;
1943
1944 return this_cpu_ptr(&percpu_buffer->buffer[0]);
1945}
1946
1947static int alloc_percpu_trace_buffer(void)
1948{
1949 struct trace_buffer_struct *buffers;
1950 struct trace_buffer_struct *sirq_buffers;
1951 struct trace_buffer_struct *irq_buffers;
1952 struct trace_buffer_struct *nmi_buffers;
1953
1954 buffers = alloc_percpu(struct trace_buffer_struct);
1955 if (!buffers)
1956 goto err_warn;
1957
1958 sirq_buffers = alloc_percpu(struct trace_buffer_struct);
1959 if (!sirq_buffers)
1960 goto err_sirq;
1961
1962 irq_buffers = alloc_percpu(struct trace_buffer_struct);
1963 if (!irq_buffers)
1964 goto err_irq;
1965
1966 nmi_buffers = alloc_percpu(struct trace_buffer_struct);
1967 if (!nmi_buffers)
1968 goto err_nmi;
1969
1970 trace_percpu_buffer = buffers;
1971 trace_percpu_sirq_buffer = sirq_buffers;
1972 trace_percpu_irq_buffer = irq_buffers;
1973 trace_percpu_nmi_buffer = nmi_buffers;
1974
1975 return 0;
1976
1977 err_nmi:
1978 free_percpu(irq_buffers);
1979 err_irq:
1980 free_percpu(sirq_buffers);
1981 err_sirq:
1982 free_percpu(buffers);
1983 err_warn:
1984 WARN(1, "Could not allocate percpu trace_printk buffer");
1985 return -ENOMEM;
1986}
1987
1988static int buffers_allocated;
1989
1990void trace_printk_init_buffers(void)
1991{
1992 if (buffers_allocated)
1993 return;
1994
1995 if (alloc_percpu_trace_buffer())
1996 return;
1997
1998 pr_info("ftrace: Allocated trace_printk buffers\n");
1999
2000 /* Expand the buffers to set size */
2001 tracing_update_buffers();
2002
2003 buffers_allocated = 1;
2004
2005 /*
2006 * trace_printk_init_buffers() can be called by modules.
2007 * If that happens, then we need to start cmdline recording
2008 * directly here. If the global_trace.buffer is already
2009 * allocated here, then this was called by module code.
2010 */
2011 if (global_trace.trace_buffer.buffer)
2012 tracing_start_cmdline_record();
2013}
2014
2015void trace_printk_start_comm(void)
2016{
2017 /* Start tracing comms if trace printk is set */
2018 if (!buffers_allocated)
2019 return;
2020 tracing_start_cmdline_record();
2021}
2022
2023static void trace_printk_start_stop_comm(int enabled)
2024{
2025 if (!buffers_allocated)
2026 return;
2027
2028 if (enabled)
2029 tracing_start_cmdline_record();
2030 else
2031 tracing_stop_cmdline_record();
2032}
2033
2034/**
2035 * trace_vbprintk - write binary msg to tracing buffer
2036 *
2037 */
2038int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
2039{
2040 struct ftrace_event_call *call = &event_bprint;
2041 struct ring_buffer_event *event;
2042 struct ring_buffer *buffer;
2043 struct trace_array *tr = &global_trace;
2044 struct bprint_entry *entry;
2045 unsigned long flags;
2046 char *tbuffer;
2047 int len = 0, size, pc;
2048
2049 if (unlikely(tracing_selftest_running || tracing_disabled))
2050 return 0;
2051
2052 /* Don't pollute graph traces with trace_vprintk internals */
2053 pause_graph_tracing();
2054
2055 pc = preempt_count();
2056 preempt_disable_notrace();
2057
2058 tbuffer = get_trace_buf();
2059 if (!tbuffer) {
2060 len = 0;
2061 goto out;
2062 }
2063
2064 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
2065
2066 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
2067 goto out;
2068
2069 local_save_flags(flags);
2070 size = sizeof(*entry) + sizeof(u32) * len;
2071 buffer = tr->trace_buffer.buffer;
2072 event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
2073 flags, pc);
2074 if (!event)
2075 goto out;
2076 entry = ring_buffer_event_data(event);
2077 entry->ip = ip;
2078 entry->fmt = fmt;
2079
2080 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
2081 if (!call_filter_check_discard(call, entry, buffer, event)) {
2082 __buffer_unlock_commit(buffer, event);
2083 ftrace_trace_stack(buffer, flags, 6, pc);
2084 }
2085
2086out:
2087 preempt_enable_notrace();
2088 unpause_graph_tracing();
2089
2090 return len;
2091}
2092EXPORT_SYMBOL_GPL(trace_vbprintk);
2093
2094static int
2095__trace_array_vprintk(struct ring_buffer *buffer,
2096 unsigned long ip, const char *fmt, va_list args)
2097{
2098 struct ftrace_event_call *call = &event_print;
2099 struct ring_buffer_event *event;
2100 int len = 0, size, pc;
2101 struct print_entry *entry;
2102 unsigned long flags;
2103 char *tbuffer;
2104
2105 if (tracing_disabled || tracing_selftest_running)
2106 return 0;
2107
2108 /* Don't pollute graph traces with trace_vprintk internals */
2109 pause_graph_tracing();
2110
2111 pc = preempt_count();
2112 preempt_disable_notrace();
2113
2114
2115 tbuffer = get_trace_buf();
2116 if (!tbuffer) {
2117 len = 0;
2118 goto out;
2119 }
2120
2121 len = vsnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
2122 if (len > TRACE_BUF_SIZE)
2123 goto out;
2124
2125 local_save_flags(flags);
2126 size = sizeof(*entry) + len + 1;
2127 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
2128 flags, pc);
2129 if (!event)
2130 goto out;
2131 entry = ring_buffer_event_data(event);
2132 entry->ip = ip;
2133
2134 memcpy(&entry->buf, tbuffer, len);
2135 entry->buf[len] = '\0';
2136 if (!call_filter_check_discard(call, entry, buffer, event)) {
2137 __buffer_unlock_commit(buffer, event);
2138 ftrace_trace_stack(buffer, flags, 6, pc);
2139 }
2140 out:
2141 preempt_enable_notrace();
2142 unpause_graph_tracing();
2143
2144 return len;
2145}
2146
2147int trace_array_vprintk(struct trace_array *tr,
2148 unsigned long ip, const char *fmt, va_list args)
2149{
2150 return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
2151}
2152
2153int trace_array_printk(struct trace_array *tr,
2154 unsigned long ip, const char *fmt, ...)
2155{
2156 int ret;
2157 va_list ap;
2158
2159 if (!(trace_flags & TRACE_ITER_PRINTK))
2160 return 0;
2161
2162 va_start(ap, fmt);
2163 ret = trace_array_vprintk(tr, ip, fmt, ap);
2164 va_end(ap);
2165 return ret;
2166}
2167
2168int trace_array_printk_buf(struct ring_buffer *buffer,
2169 unsigned long ip, const char *fmt, ...)
2170{
2171 int ret;
2172 va_list ap;
2173
2174 if (!(trace_flags & TRACE_ITER_PRINTK))
2175 return 0;
2176
2177 va_start(ap, fmt);
2178 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
2179 va_end(ap);
2180 return ret;
2181}
2182
2183int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
2184{
2185 return trace_array_vprintk(&global_trace, ip, fmt, args);
2186}
2187EXPORT_SYMBOL_GPL(trace_vprintk);
2188
2189static void trace_iterator_increment(struct trace_iterator *iter)
2190{
2191 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
2192
2193 iter->idx++;
2194 if (buf_iter)
2195 ring_buffer_read(buf_iter, NULL);
2196}
2197
2198static struct trace_entry *
2199peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
2200 unsigned long *lost_events)
2201{
2202 struct ring_buffer_event *event;
2203 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
2204
2205 if (buf_iter)
2206 event = ring_buffer_iter_peek(buf_iter, ts);
2207 else
2208 event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts,
2209 lost_events);
2210
2211 if (event) {
2212 iter->ent_size = ring_buffer_event_length(event);
2213 return ring_buffer_event_data(event);
2214 }
2215 iter->ent_size = 0;
2216 return NULL;
2217}
2218
2219static struct trace_entry *
2220__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
2221 unsigned long *missing_events, u64 *ent_ts)
2222{
2223 struct ring_buffer *buffer = iter->trace_buffer->buffer;
2224 struct trace_entry *ent, *next = NULL;
2225 unsigned long lost_events = 0, next_lost = 0;
2226 int cpu_file = iter->cpu_file;
2227 u64 next_ts = 0, ts;
2228 int next_cpu = -1;
2229 int next_size = 0;
2230 int cpu;
2231
2232 /*
2233 * If we are in a per_cpu trace file, don't bother by iterating over
2234 * all cpu and peek directly.
2235 */
2236 if (cpu_file > RING_BUFFER_ALL_CPUS) {
2237 if (ring_buffer_empty_cpu(buffer, cpu_file))
2238 return NULL;
2239 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
2240 if (ent_cpu)
2241 *ent_cpu = cpu_file;
2242
2243 return ent;
2244 }
2245
2246 for_each_tracing_cpu(cpu) {
2247
2248 if (ring_buffer_empty_cpu(buffer, cpu))
2249 continue;
2250
2251 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
2252
2253 /*
2254 * Pick the entry with the smallest timestamp:
2255 */
2256 if (ent && (!next || ts < next_ts)) {
2257 next = ent;
2258 next_cpu = cpu;
2259 next_ts = ts;
2260 next_lost = lost_events;
2261 next_size = iter->ent_size;
2262 }
2263 }
2264
2265 iter->ent_size = next_size;
2266
2267 if (ent_cpu)
2268 *ent_cpu = next_cpu;
2269
2270 if (ent_ts)
2271 *ent_ts = next_ts;
2272
2273 if (missing_events)
2274 *missing_events = next_lost;
2275
2276 return next;
2277}
2278
2279/* Find the next real entry, without updating the iterator itself */
2280struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
2281 int *ent_cpu, u64 *ent_ts)
2282{
2283 return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
2284}
2285
2286/* Find the next real entry, and increment the iterator to the next entry */
2287void *trace_find_next_entry_inc(struct trace_iterator *iter)
2288{
2289 iter->ent = __find_next_entry(iter, &iter->cpu,
2290 &iter->lost_events, &iter->ts);
2291
2292 if (iter->ent)
2293 trace_iterator_increment(iter);
2294
2295 return iter->ent ? iter : NULL;
2296}
2297
2298static void trace_consume(struct trace_iterator *iter)
2299{
2300 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts,
2301 &iter->lost_events);
2302}
2303
2304static void *s_next(struct seq_file *m, void *v, loff_t *pos)
2305{
2306 struct trace_iterator *iter = m->private;
2307 int i = (int)*pos;
2308 void *ent;
2309
2310 WARN_ON_ONCE(iter->leftover);
2311
2312 (*pos)++;
2313
2314 /* can't go backwards */
2315 if (iter->idx > i)
2316 return NULL;
2317
2318 if (iter->idx < 0)
2319 ent = trace_find_next_entry_inc(iter);
2320 else
2321 ent = iter;
2322
2323 while (ent && iter->idx < i)
2324 ent = trace_find_next_entry_inc(iter);
2325
2326 iter->pos = *pos;
2327
2328 return ent;
2329}
2330
2331void tracing_iter_reset(struct trace_iterator *iter, int cpu)
2332{
2333 struct ring_buffer_event *event;
2334 struct ring_buffer_iter *buf_iter;
2335 unsigned long entries = 0;
2336 u64 ts;
2337
2338 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0;
2339
2340 buf_iter = trace_buffer_iter(iter, cpu);
2341 if (!buf_iter)
2342 return;
2343
2344 ring_buffer_iter_reset(buf_iter);
2345
2346 /*
2347 * We could have the case with the max latency tracers
2348 * that a reset never took place on a cpu. This is evident
2349 * by the timestamp being before the start of the buffer.
2350 */
2351 while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
2352 if (ts >= iter->trace_buffer->time_start)
2353 break;
2354 entries++;
2355 ring_buffer_read(buf_iter, NULL);
2356 }
2357
2358 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries;
2359}
2360
2361/*
2362 * The current tracer is copied to avoid a global locking
2363 * all around.
2364 */
2365static void *s_start(struct seq_file *m, loff_t *pos)
2366{
2367 struct trace_iterator *iter = m->private;
2368 struct trace_array *tr = iter->tr;
2369 int cpu_file = iter->cpu_file;
2370 void *p = NULL;
2371 loff_t l = 0;
2372 int cpu;
2373
2374 /*
2375 * copy the tracer to avoid using a global lock all around.
2376 * iter->trace is a copy of current_trace, the pointer to the
2377 * name may be used instead of a strcmp(), as iter->trace->name
2378 * will point to the same string as current_trace->name.
2379 */
2380 mutex_lock(&trace_types_lock);
2381 if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
2382 *iter->trace = *tr->current_trace;
2383 mutex_unlock(&trace_types_lock);
2384
2385#ifdef CONFIG_TRACER_MAX_TRACE
2386 if (iter->snapshot && iter->trace->use_max_tr)
2387 return ERR_PTR(-EBUSY);
2388#endif
2389
2390 if (!iter->snapshot)
2391 atomic_inc(&trace_record_cmdline_disabled);
2392
2393 if (*pos != iter->pos) {
2394 iter->ent = NULL;
2395 iter->cpu = 0;
2396 iter->idx = -1;
2397
2398 if (cpu_file == RING_BUFFER_ALL_CPUS) {
2399 for_each_tracing_cpu(cpu)
2400 tracing_iter_reset(iter, cpu);
2401 } else
2402 tracing_iter_reset(iter, cpu_file);
2403
2404 iter->leftover = 0;
2405 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
2406 ;
2407
2408 } else {
2409 /*
2410 * If we overflowed the seq_file before, then we want
2411 * to just reuse the trace_seq buffer again.
2412 */
2413 if (iter->leftover)
2414 p = iter;
2415 else {
2416 l = *pos - 1;
2417 p = s_next(m, p, &l);
2418 }
2419 }
2420
2421 trace_event_read_lock();
2422 trace_access_lock(cpu_file);
2423 return p;
2424}
2425
2426static void s_stop(struct seq_file *m, void *p)
2427{
2428 struct trace_iterator *iter = m->private;
2429
2430#ifdef CONFIG_TRACER_MAX_TRACE
2431 if (iter->snapshot && iter->trace->use_max_tr)
2432 return;
2433#endif
2434
2435 if (!iter->snapshot)
2436 atomic_dec(&trace_record_cmdline_disabled);
2437
2438 trace_access_unlock(iter->cpu_file);
2439 trace_event_read_unlock();
2440}
2441
2442static void
2443get_total_entries(struct trace_buffer *buf,
2444 unsigned long *total, unsigned long *entries)
2445{
2446 unsigned long count;
2447 int cpu;
2448
2449 *total = 0;
2450 *entries = 0;
2451
2452 for_each_tracing_cpu(cpu) {
2453 count = ring_buffer_entries_cpu(buf->buffer, cpu);
2454 /*
2455 * If this buffer has skipped entries, then we hold all
2456 * entries for the trace and we need to ignore the
2457 * ones before the time stamp.
2458 */
2459 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
2460 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
2461 /* total is the same as the entries */
2462 *total += count;
2463 } else
2464 *total += count +
2465 ring_buffer_overrun_cpu(buf->buffer, cpu);
2466 *entries += count;
2467 }
2468}
2469
2470static void print_lat_help_header(struct seq_file *m)
2471{
2472 seq_puts(m, "# _------=> CPU# \n");
2473 seq_puts(m, "# / _-----=> irqs-off \n");
2474 seq_puts(m, "# | / _----=> need-resched \n");
2475 seq_puts(m, "# || / _---=> hardirq/softirq \n");
2476 seq_puts(m, "# ||| / _--=> preempt-depth \n");
2477 seq_puts(m, "# |||| / delay \n");
2478 seq_puts(m, "# cmd pid ||||| time | caller \n");
2479 seq_puts(m, "# \\ / ||||| \\ | / \n");
2480}
2481
2482static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
2483{
2484 unsigned long total;
2485 unsigned long entries;
2486
2487 get_total_entries(buf, &total, &entries);
2488 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2489 entries, total, num_online_cpus());
2490 seq_puts(m, "#\n");
2491}
2492
2493static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m)
2494{
2495 print_event_info(buf, m);
2496 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2497 seq_puts(m, "# | | | | |\n");
2498}
2499
2500static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m)
2501{
2502 print_event_info(buf, m);
2503 seq_puts(m, "# _-----=> irqs-off\n");
2504 seq_puts(m, "# / _----=> need-resched\n");
2505 seq_puts(m, "# | / _---=> hardirq/softirq\n");
2506 seq_puts(m, "# || / _--=> preempt-depth\n");
2507 seq_puts(m, "# ||| / delay\n");
2508 seq_puts(m, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2509 seq_puts(m, "# | | | |||| | |\n");
2510}
2511
2512void
2513print_trace_header(struct seq_file *m, struct trace_iterator *iter)
2514{
2515 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
2516 struct trace_buffer *buf = iter->trace_buffer;
2517 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
2518 struct tracer *type = iter->trace;
2519 unsigned long entries;
2520 unsigned long total;
2521 const char *name = "preemption";
2522
2523 name = type->name;
2524
2525 get_total_entries(buf, &total, &entries);
2526
2527 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
2528 name, UTS_RELEASE);
2529 seq_puts(m, "# -----------------------------------"
2530 "---------------------------------\n");
2531 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2532 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2533 nsecs_to_usecs(data->saved_latency),
2534 entries,
2535 total,
2536 buf->cpu,
2537#if defined(CONFIG_PREEMPT_NONE)
2538 "server",
2539#elif defined(CONFIG_PREEMPT_VOLUNTARY)
2540 "desktop",
2541#elif defined(CONFIG_PREEMPT)
2542 "preempt",
2543#else
2544 "unknown",
2545#endif
2546 /* These are reserved for later use */
2547 0, 0, 0, 0);
2548#ifdef CONFIG_SMP
2549 seq_printf(m, " #P:%d)\n", num_online_cpus());
2550#else
2551 seq_puts(m, ")\n");
2552#endif
2553 seq_puts(m, "# -----------------\n");
2554 seq_printf(m, "# | task: %.16s-%d "
2555 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2556 data->comm, data->pid,
2557 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
2558 data->policy, data->rt_priority);
2559 seq_puts(m, "# -----------------\n");
2560
2561 if (data->critical_start) {
2562 seq_puts(m, "# => started at: ");
2563 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
2564 trace_print_seq(m, &iter->seq);
2565 seq_puts(m, "\n# => ended at: ");
2566 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
2567 trace_print_seq(m, &iter->seq);
2568 seq_puts(m, "\n#\n");
2569 }
2570
2571 seq_puts(m, "#\n");
2572}
2573
2574static void test_cpu_buff_start(struct trace_iterator *iter)
2575{
2576 struct trace_seq *s = &iter->seq;
2577
2578 if (!(trace_flags & TRACE_ITER_ANNOTATE))
2579 return;
2580
2581 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
2582 return;
2583
2584 if (cpumask_test_cpu(iter->cpu, iter->started))
2585 return;
2586
2587 if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries)
2588 return;
2589
2590 cpumask_set_cpu(iter->cpu, iter->started);
2591
2592 /* Don't print started cpu buffer for the first entry of the trace */
2593 if (iter->idx > 1)
2594 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
2595 iter->cpu);
2596}
2597
2598static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
2599{
2600 struct trace_seq *s = &iter->seq;
2601 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
2602 struct trace_entry *entry;
2603 struct trace_event *event;
2604
2605 entry = iter->ent;
2606
2607 test_cpu_buff_start(iter);
2608
2609 event = ftrace_find_event(entry->type);
2610
2611 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2612 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2613 if (!trace_print_lat_context(iter))
2614 goto partial;
2615 } else {
2616 if (!trace_print_context(iter))
2617 goto partial;
2618 }
2619 }
2620
2621 if (event)
2622 return event->funcs->trace(iter, sym_flags, event);
2623
2624 if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
2625 goto partial;
2626
2627 return TRACE_TYPE_HANDLED;
2628partial:
2629 return TRACE_TYPE_PARTIAL_LINE;
2630}
2631
2632static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
2633{
2634 struct trace_seq *s = &iter->seq;
2635 struct trace_entry *entry;
2636 struct trace_event *event;
2637
2638 entry = iter->ent;
2639
2640 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2641 if (!trace_seq_printf(s, "%d %d %llu ",
2642 entry->pid, iter->cpu, iter->ts))
2643 goto partial;
2644 }
2645
2646 event = ftrace_find_event(entry->type);
2647 if (event)
2648 return event->funcs->raw(iter, 0, event);
2649
2650 if (!trace_seq_printf(s, "%d ?\n", entry->type))
2651 goto partial;
2652
2653 return TRACE_TYPE_HANDLED;
2654partial:
2655 return TRACE_TYPE_PARTIAL_LINE;
2656}
2657
2658static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
2659{
2660 struct trace_seq *s = &iter->seq;
2661 unsigned char newline = '\n';
2662 struct trace_entry *entry;
2663 struct trace_event *event;
2664
2665 entry = iter->ent;
2666
2667 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2668 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
2669 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
2670 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
2671 }
2672
2673 event = ftrace_find_event(entry->type);
2674 if (event) {
2675 enum print_line_t ret = event->funcs->hex(iter, 0, event);
2676 if (ret != TRACE_TYPE_HANDLED)
2677 return ret;
2678 }
2679
2680 SEQ_PUT_FIELD_RET(s, newline);
2681
2682 return TRACE_TYPE_HANDLED;
2683}
2684
2685static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
2686{
2687 struct trace_seq *s = &iter->seq;
2688 struct trace_entry *entry;
2689 struct trace_event *event;
2690
2691 entry = iter->ent;
2692
2693 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2694 SEQ_PUT_FIELD_RET(s, entry->pid);
2695 SEQ_PUT_FIELD_RET(s, iter->cpu);
2696 SEQ_PUT_FIELD_RET(s, iter->ts);
2697 }
2698
2699 event = ftrace_find_event(entry->type);
2700 return event ? event->funcs->binary(iter, 0, event) :
2701 TRACE_TYPE_HANDLED;
2702}
2703
2704int trace_empty(struct trace_iterator *iter)
2705{
2706 struct ring_buffer_iter *buf_iter;
2707 int cpu;
2708
2709 /* If we are looking at one CPU buffer, only check that one */
2710 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
2711 cpu = iter->cpu_file;
2712 buf_iter = trace_buffer_iter(iter, cpu);
2713 if (buf_iter) {
2714 if (!ring_buffer_iter_empty(buf_iter))
2715 return 0;
2716 } else {
2717 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
2718 return 0;
2719 }
2720 return 1;
2721 }
2722
2723 for_each_tracing_cpu(cpu) {
2724 buf_iter = trace_buffer_iter(iter, cpu);
2725 if (buf_iter) {
2726 if (!ring_buffer_iter_empty(buf_iter))
2727 return 0;
2728 } else {
2729 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
2730 return 0;
2731 }
2732 }
2733
2734 return 1;
2735}
2736
2737/* Called with trace_event_read_lock() held. */
2738enum print_line_t print_trace_line(struct trace_iterator *iter)
2739{
2740 enum print_line_t ret;
2741
2742 if (iter->lost_events &&
2743 !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
2744 iter->cpu, iter->lost_events))
2745 return TRACE_TYPE_PARTIAL_LINE;
2746
2747 if (iter->trace && iter->trace->print_line) {
2748 ret = iter->trace->print_line(iter);
2749 if (ret != TRACE_TYPE_UNHANDLED)
2750 return ret;
2751 }
2752
2753 if (iter->ent->type == TRACE_BPUTS &&
2754 trace_flags & TRACE_ITER_PRINTK &&
2755 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2756 return trace_print_bputs_msg_only(iter);
2757
2758 if (iter->ent->type == TRACE_BPRINT &&
2759 trace_flags & TRACE_ITER_PRINTK &&
2760 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2761 return trace_print_bprintk_msg_only(iter);
2762
2763 if (iter->ent->type == TRACE_PRINT &&
2764 trace_flags & TRACE_ITER_PRINTK &&
2765 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2766 return trace_print_printk_msg_only(iter);
2767
2768 if (trace_flags & TRACE_ITER_BIN)
2769 return print_bin_fmt(iter);
2770
2771 if (trace_flags & TRACE_ITER_HEX)
2772 return print_hex_fmt(iter);
2773
2774 if (trace_flags & TRACE_ITER_RAW)
2775 return print_raw_fmt(iter);
2776
2777 return print_trace_fmt(iter);
2778}
2779
2780void trace_latency_header(struct seq_file *m)
2781{
2782 struct trace_iterator *iter = m->private;
2783
2784 /* print nothing if the buffers are empty */
2785 if (trace_empty(iter))
2786 return;
2787
2788 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
2789 print_trace_header(m, iter);
2790
2791 if (!(trace_flags & TRACE_ITER_VERBOSE))
2792 print_lat_help_header(m);
2793}
2794
2795void trace_default_header(struct seq_file *m)
2796{
2797 struct trace_iterator *iter = m->private;
2798
2799 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
2800 return;
2801
2802 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2803 /* print nothing if the buffers are empty */
2804 if (trace_empty(iter))
2805 return;
2806 print_trace_header(m, iter);
2807 if (!(trace_flags & TRACE_ITER_VERBOSE))
2808 print_lat_help_header(m);
2809 } else {
2810 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
2811 if (trace_flags & TRACE_ITER_IRQ_INFO)
2812 print_func_help_header_irq(iter->trace_buffer, m);
2813 else
2814 print_func_help_header(iter->trace_buffer, m);
2815 }
2816 }
2817}
2818
2819static void test_ftrace_alive(struct seq_file *m)
2820{
2821 if (!ftrace_is_dead())
2822 return;
2823 seq_printf(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2824 seq_printf(m, "# MAY BE MISSING FUNCTION EVENTS\n");
2825}
2826
2827#ifdef CONFIG_TRACER_MAX_TRACE
2828static void show_snapshot_main_help(struct seq_file *m)
2829{
2830 seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
2831 seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2832 seq_printf(m, "# Takes a snapshot of the main buffer.\n");
2833 seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n");
2834 seq_printf(m, "# (Doesn't have to be '2' works with any number that\n");
2835 seq_printf(m, "# is not a '0' or '1')\n");
2836}
2837
2838static void show_snapshot_percpu_help(struct seq_file *m)
2839{
2840 seq_printf(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2841#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2842 seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2843 seq_printf(m, "# Takes a snapshot of the main buffer for this cpu.\n");
2844#else
2845 seq_printf(m, "# echo 1 > snapshot : Not supported with this kernel.\n");
2846 seq_printf(m, "# Must use main snapshot file to allocate.\n");
2847#endif
2848 seq_printf(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
2849 seq_printf(m, "# (Doesn't have to be '2' works with any number that\n");
2850 seq_printf(m, "# is not a '0' or '1')\n");
2851}
2852
2853static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
2854{
2855 if (iter->tr->allocated_snapshot)
2856 seq_printf(m, "#\n# * Snapshot is allocated *\n#\n");
2857 else
2858 seq_printf(m, "#\n# * Snapshot is freed *\n#\n");
2859
2860 seq_printf(m, "# Snapshot commands:\n");
2861 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
2862 show_snapshot_main_help(m);
2863 else
2864 show_snapshot_percpu_help(m);
2865}
2866#else
2867/* Should never be called */
2868static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
2869#endif
2870
2871static int s_show(struct seq_file *m, void *v)
2872{
2873 struct trace_iterator *iter = v;
2874 int ret;
2875
2876 if (iter->ent == NULL) {
2877 if (iter->tr) {
2878 seq_printf(m, "# tracer: %s\n", iter->trace->name);
2879 seq_puts(m, "#\n");
2880 test_ftrace_alive(m);
2881 }
2882 if (iter->snapshot && trace_empty(iter))
2883 print_snapshot_help(m, iter);
2884 else if (iter->trace && iter->trace->print_header)
2885 iter->trace->print_header(m);
2886 else
2887 trace_default_header(m);
2888
2889 } else if (iter->leftover) {
2890 /*
2891 * If we filled the seq_file buffer earlier, we
2892 * want to just show it now.
2893 */
2894 ret = trace_print_seq(m, &iter->seq);
2895
2896 /* ret should this time be zero, but you never know */
2897 iter->leftover = ret;
2898
2899 } else {
2900 print_trace_line(iter);
2901 ret = trace_print_seq(m, &iter->seq);
2902 /*
2903 * If we overflow the seq_file buffer, then it will
2904 * ask us for this data again at start up.
2905 * Use that instead.
2906 * ret is 0 if seq_file write succeeded.
2907 * -1 otherwise.
2908 */
2909 iter->leftover = ret;
2910 }
2911
2912 return 0;
2913}
2914
2915/*
2916 * Should be used after trace_array_get(), trace_types_lock
2917 * ensures that i_cdev was already initialized.
2918 */
2919static inline int tracing_get_cpu(struct inode *inode)
2920{
2921 if (inode->i_cdev) /* See trace_create_cpu_file() */
2922 return (long)inode->i_cdev - 1;
2923 return RING_BUFFER_ALL_CPUS;
2924}
2925
2926static const struct seq_operations tracer_seq_ops = {
2927 .start = s_start,
2928 .next = s_next,
2929 .stop = s_stop,
2930 .show = s_show,
2931};
2932
2933static struct trace_iterator *
2934__tracing_open(struct inode *inode, struct file *file, bool snapshot)
2935{
2936 struct trace_array *tr = inode->i_private;
2937 struct trace_iterator *iter;
2938 int cpu;
2939
2940 if (tracing_disabled)
2941 return ERR_PTR(-ENODEV);
2942
2943 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
2944 if (!iter)
2945 return ERR_PTR(-ENOMEM);
2946
2947 iter->buffer_iter = kzalloc(sizeof(*iter->buffer_iter) * num_possible_cpus(),
2948 GFP_KERNEL);
2949 if (!iter->buffer_iter)
2950 goto release;
2951
2952 /*
2953 * We make a copy of the current tracer to avoid concurrent
2954 * changes on it while we are reading.
2955 */
2956 mutex_lock(&trace_types_lock);
2957 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
2958 if (!iter->trace)
2959 goto fail;
2960
2961 *iter->trace = *tr->current_trace;
2962
2963 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
2964 goto fail;
2965
2966 iter->tr = tr;
2967
2968#ifdef CONFIG_TRACER_MAX_TRACE
2969 /* Currently only the top directory has a snapshot */
2970 if (tr->current_trace->print_max || snapshot)
2971 iter->trace_buffer = &tr->max_buffer;
2972 else
2973#endif
2974 iter->trace_buffer = &tr->trace_buffer;
2975 iter->snapshot = snapshot;
2976 iter->pos = -1;
2977 iter->cpu_file = tracing_get_cpu(inode);
2978 mutex_init(&iter->mutex);
2979
2980 /* Notify the tracer early; before we stop tracing. */
2981 if (iter->trace && iter->trace->open)
2982 iter->trace->open(iter);
2983
2984 /* Annotate start of buffers if we had overruns */
2985 if (ring_buffer_overruns(iter->trace_buffer->buffer))
2986 iter->iter_flags |= TRACE_FILE_ANNOTATE;
2987
2988 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
2989 if (trace_clocks[tr->clock_id].in_ns)
2990 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
2991
2992 /* stop the trace while dumping if we are not opening "snapshot" */
2993 if (!iter->snapshot)
2994 tracing_stop_tr(tr);
2995
2996 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
2997 for_each_tracing_cpu(cpu) {
2998 iter->buffer_iter[cpu] =
2999 ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
3000 }
3001 ring_buffer_read_prepare_sync();
3002 for_each_tracing_cpu(cpu) {
3003 ring_buffer_read_start(iter->buffer_iter[cpu]);
3004 tracing_iter_reset(iter, cpu);
3005 }
3006 } else {
3007 cpu = iter->cpu_file;
3008 iter->buffer_iter[cpu] =
3009 ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
3010 ring_buffer_read_prepare_sync();
3011 ring_buffer_read_start(iter->buffer_iter[cpu]);
3012 tracing_iter_reset(iter, cpu);
3013 }
3014
3015 mutex_unlock(&trace_types_lock);
3016
3017 return iter;
3018
3019 fail:
3020 mutex_unlock(&trace_types_lock);
3021 kfree(iter->trace);
3022 kfree(iter->buffer_iter);
3023release:
3024 seq_release_private(inode, file);
3025 return ERR_PTR(-ENOMEM);
3026}
3027
3028int tracing_open_generic(struct inode *inode, struct file *filp)
3029{
3030 if (tracing_disabled)
3031 return -ENODEV;
3032
3033 filp->private_data = inode->i_private;
3034 return 0;
3035}
3036
3037bool tracing_is_disabled(void)
3038{
3039 return (tracing_disabled) ? true: false;
3040}
3041
3042/*
3043 * Open and update trace_array ref count.
3044 * Must have the current trace_array passed to it.
3045 */
3046static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
3047{
3048 struct trace_array *tr = inode->i_private;
3049
3050 if (tracing_disabled)
3051 return -ENODEV;
3052
3053 if (trace_array_get(tr) < 0)
3054 return -ENODEV;
3055
3056 filp->private_data = inode->i_private;
3057
3058 return 0;
3059}
3060
3061static int tracing_release(struct inode *inode, struct file *file)
3062{
3063 struct trace_array *tr = inode->i_private;
3064 struct seq_file *m = file->private_data;
3065 struct trace_iterator *iter;
3066 int cpu;
3067
3068 if (!(file->f_mode & FMODE_READ)) {
3069 trace_array_put(tr);
3070 return 0;
3071 }
3072
3073 /* Writes do not use seq_file */
3074 iter = m->private;
3075 mutex_lock(&trace_types_lock);
3076
3077 for_each_tracing_cpu(cpu) {
3078 if (iter->buffer_iter[cpu])
3079 ring_buffer_read_finish(iter->buffer_iter[cpu]);
3080 }
3081
3082 if (iter->trace && iter->trace->close)
3083 iter->trace->close(iter);
3084
3085 if (!iter->snapshot)
3086 /* reenable tracing if it was previously enabled */
3087 tracing_start_tr(tr);
3088
3089 __trace_array_put(tr);
3090
3091 mutex_unlock(&trace_types_lock);
3092
3093 mutex_destroy(&iter->mutex);
3094 free_cpumask_var(iter->started);
3095 kfree(iter->trace);
3096 kfree(iter->buffer_iter);
3097 seq_release_private(inode, file);
3098
3099 return 0;
3100}
3101
3102static int tracing_release_generic_tr(struct inode *inode, struct file *file)
3103{
3104 struct trace_array *tr = inode->i_private;
3105
3106 trace_array_put(tr);
3107 return 0;
3108}
3109
3110static int tracing_single_release_tr(struct inode *inode, struct file *file)
3111{
3112 struct trace_array *tr = inode->i_private;
3113
3114 trace_array_put(tr);
3115
3116 return single_release(inode, file);
3117}
3118
3119static int tracing_open(struct inode *inode, struct file *file)
3120{
3121 struct trace_array *tr = inode->i_private;
3122 struct trace_iterator *iter;
3123 int ret = 0;
3124
3125 if (trace_array_get(tr) < 0)
3126 return -ENODEV;
3127
3128 /* If this file was open for write, then erase contents */
3129 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
3130 int cpu = tracing_get_cpu(inode);
3131
3132 if (cpu == RING_BUFFER_ALL_CPUS)
3133 tracing_reset_online_cpus(&tr->trace_buffer);
3134 else
3135 tracing_reset(&tr->trace_buffer, cpu);
3136 }
3137
3138 if (file->f_mode & FMODE_READ) {
3139 iter = __tracing_open(inode, file, false);
3140 if (IS_ERR(iter))
3141 ret = PTR_ERR(iter);
3142 else if (trace_flags & TRACE_ITER_LATENCY_FMT)
3143 iter->iter_flags |= TRACE_FILE_LAT_FMT;
3144 }
3145
3146 if (ret < 0)
3147 trace_array_put(tr);
3148
3149 return ret;
3150}
3151
3152/*
3153 * Some tracers are not suitable for instance buffers.
3154 * A tracer is always available for the global array (toplevel)
3155 * or if it explicitly states that it is.
3156 */
3157static bool
3158trace_ok_for_array(struct tracer *t, struct trace_array *tr)
3159{
3160 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
3161}
3162
3163/* Find the next tracer that this trace array may use */
3164static struct tracer *
3165get_tracer_for_array(struct trace_array *tr, struct tracer *t)
3166{
3167 while (t && !trace_ok_for_array(t, tr))
3168 t = t->next;
3169
3170 return t;
3171}
3172
3173static void *
3174t_next(struct seq_file *m, void *v, loff_t *pos)
3175{
3176 struct trace_array *tr = m->private;
3177 struct tracer *t = v;
3178
3179 (*pos)++;
3180
3181 if (t)
3182 t = get_tracer_for_array(tr, t->next);
3183
3184 return t;
3185}
3186
3187static void *t_start(struct seq_file *m, loff_t *pos)
3188{
3189 struct trace_array *tr = m->private;
3190 struct tracer *t;
3191 loff_t l = 0;
3192
3193 mutex_lock(&trace_types_lock);
3194
3195 t = get_tracer_for_array(tr, trace_types);
3196 for (; t && l < *pos; t = t_next(m, t, &l))
3197 ;
3198
3199 return t;
3200}
3201
3202static void t_stop(struct seq_file *m, void *p)
3203{
3204 mutex_unlock(&trace_types_lock);
3205}
3206
3207static int t_show(struct seq_file *m, void *v)
3208{
3209 struct tracer *t = v;
3210
3211 if (!t)
3212 return 0;
3213
3214 seq_printf(m, "%s", t->name);
3215 if (t->next)
3216 seq_putc(m, ' ');
3217 else
3218 seq_putc(m, '\n');
3219
3220 return 0;
3221}
3222
3223static const struct seq_operations show_traces_seq_ops = {
3224 .start = t_start,
3225 .next = t_next,
3226 .stop = t_stop,
3227 .show = t_show,
3228};
3229
3230static int show_traces_open(struct inode *inode, struct file *file)
3231{
3232 struct trace_array *tr = inode->i_private;
3233 struct seq_file *m;
3234 int ret;
3235
3236 if (tracing_disabled)
3237 return -ENODEV;
3238
3239 ret = seq_open(file, &show_traces_seq_ops);
3240 if (ret)
3241 return ret;
3242
3243 m = file->private_data;
3244 m->private = tr;
3245
3246 return 0;
3247}
3248
3249static ssize_t
3250tracing_write_stub(struct file *filp, const char __user *ubuf,
3251 size_t count, loff_t *ppos)
3252{
3253 return count;
3254}
3255
3256loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
3257{
3258 int ret;
3259
3260 if (file->f_mode & FMODE_READ)
3261 ret = seq_lseek(file, offset, whence);
3262 else
3263 file->f_pos = ret = 0;
3264
3265 return ret;
3266}
3267
3268static const struct file_operations tracing_fops = {
3269 .open = tracing_open,
3270 .read = seq_read,
3271 .write = tracing_write_stub,
3272 .llseek = tracing_lseek,
3273 .release = tracing_release,
3274};
3275
3276static const struct file_operations show_traces_fops = {
3277 .open = show_traces_open,
3278 .read = seq_read,
3279 .release = seq_release,
3280 .llseek = seq_lseek,
3281};
3282
3283/*
3284 * The tracer itself will not take this lock, but still we want
3285 * to provide a consistent cpumask to user-space:
3286 */
3287static DEFINE_MUTEX(tracing_cpumask_update_lock);
3288
3289/*
3290 * Temporary storage for the character representation of the
3291 * CPU bitmask (and one more byte for the newline):
3292 */
3293static char mask_str[NR_CPUS + 1];
3294
3295static ssize_t
3296tracing_cpumask_read(struct file *filp, char __user *ubuf,
3297 size_t count, loff_t *ppos)
3298{
3299 struct trace_array *tr = file_inode(filp)->i_private;
3300 int len;
3301
3302 mutex_lock(&tracing_cpumask_update_lock);
3303
3304 len = cpumask_scnprintf(mask_str, count, tr->tracing_cpumask);
3305 if (count - len < 2) {
3306 count = -EINVAL;
3307 goto out_err;
3308 }
3309 len += sprintf(mask_str + len, "\n");
3310 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
3311
3312out_err:
3313 mutex_unlock(&tracing_cpumask_update_lock);
3314
3315 return count;
3316}
3317
3318static ssize_t
3319tracing_cpumask_write(struct file *filp, const char __user *ubuf,
3320 size_t count, loff_t *ppos)
3321{
3322 struct trace_array *tr = file_inode(filp)->i_private;
3323 cpumask_var_t tracing_cpumask_new;
3324 int err, cpu;
3325
3326 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
3327 return -ENOMEM;
3328
3329 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
3330 if (err)
3331 goto err_unlock;
3332
3333 mutex_lock(&tracing_cpumask_update_lock);
3334
3335 local_irq_disable();
3336 arch_spin_lock(&ftrace_max_lock);
3337 for_each_tracing_cpu(cpu) {
3338 /*
3339 * Increase/decrease the disabled counter if we are
3340 * about to flip a bit in the cpumask:
3341 */
3342 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
3343 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
3344 atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
3345 ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);
3346 }
3347 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
3348 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
3349 atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
3350 ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
3351 }
3352 }
3353 arch_spin_unlock(&ftrace_max_lock);
3354 local_irq_enable();
3355
3356 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
3357
3358 mutex_unlock(&tracing_cpumask_update_lock);
3359 free_cpumask_var(tracing_cpumask_new);
3360
3361 return count;
3362
3363err_unlock:
3364 free_cpumask_var(tracing_cpumask_new);
3365
3366 return err;
3367}
3368
3369static const struct file_operations tracing_cpumask_fops = {
3370 .open = tracing_open_generic_tr,
3371 .read = tracing_cpumask_read,
3372 .write = tracing_cpumask_write,
3373 .release = tracing_release_generic_tr,
3374 .llseek = generic_file_llseek,
3375};
3376
3377static int tracing_trace_options_show(struct seq_file *m, void *v)
3378{
3379 struct tracer_opt *trace_opts;
3380 struct trace_array *tr = m->private;
3381 u32 tracer_flags;
3382 int i;
3383
3384 mutex_lock(&trace_types_lock);
3385 tracer_flags = tr->current_trace->flags->val;
3386 trace_opts = tr->current_trace->flags->opts;
3387
3388 for (i = 0; trace_options[i]; i++) {
3389 if (trace_flags & (1 << i))
3390 seq_printf(m, "%s\n", trace_options[i]);
3391 else
3392 seq_printf(m, "no%s\n", trace_options[i]);
3393 }
3394
3395 for (i = 0; trace_opts[i].name; i++) {
3396 if (tracer_flags & trace_opts[i].bit)
3397 seq_printf(m, "%s\n", trace_opts[i].name);
3398 else
3399 seq_printf(m, "no%s\n", trace_opts[i].name);
3400 }
3401 mutex_unlock(&trace_types_lock);
3402
3403 return 0;
3404}
3405
3406static int __set_tracer_option(struct trace_array *tr,
3407 struct tracer_flags *tracer_flags,
3408 struct tracer_opt *opts, int neg)
3409{
3410 struct tracer *trace = tr->current_trace;
3411 int ret;
3412
3413 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
3414 if (ret)
3415 return ret;
3416
3417 if (neg)
3418 tracer_flags->val &= ~opts->bit;
3419 else
3420 tracer_flags->val |= opts->bit;
3421 return 0;
3422}
3423
3424/* Try to assign a tracer specific option */
3425static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
3426{
3427 struct tracer *trace = tr->current_trace;
3428 struct tracer_flags *tracer_flags = trace->flags;
3429 struct tracer_opt *opts = NULL;
3430 int i;
3431
3432 for (i = 0; tracer_flags->opts[i].name; i++) {
3433 opts = &tracer_flags->opts[i];
3434
3435 if (strcmp(cmp, opts->name) == 0)
3436 return __set_tracer_option(tr, trace->flags, opts, neg);
3437 }
3438
3439 return -EINVAL;
3440}
3441
3442/* Some tracers require overwrite to stay enabled */
3443int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
3444{
3445 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
3446 return -1;
3447
3448 return 0;
3449}
3450
3451int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
3452{
3453 /* do nothing if flag is already set */
3454 if (!!(trace_flags & mask) == !!enabled)
3455 return 0;
3456
3457 /* Give the tracer a chance to approve the change */
3458 if (tr->current_trace->flag_changed)
3459 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
3460 return -EINVAL;
3461
3462 if (enabled)
3463 trace_flags |= mask;
3464 else
3465 trace_flags &= ~mask;
3466
3467 if (mask == TRACE_ITER_RECORD_CMD)
3468 trace_event_enable_cmd_record(enabled);
3469
3470 if (mask == TRACE_ITER_OVERWRITE) {
3471 ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled);
3472#ifdef CONFIG_TRACER_MAX_TRACE
3473 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
3474#endif
3475 }
3476
3477 if (mask == TRACE_ITER_PRINTK)
3478 trace_printk_start_stop_comm(enabled);
3479
3480 return 0;
3481}
3482
3483static int trace_set_options(struct trace_array *tr, char *option)
3484{
3485 char *cmp;
3486 int neg = 0;
3487 int ret = -ENODEV;
3488 int i;
3489
3490 cmp = strstrip(option);
3491
3492 if (strncmp(cmp, "no", 2) == 0) {
3493 neg = 1;
3494 cmp += 2;
3495 }
3496
3497 mutex_lock(&trace_types_lock);
3498
3499 for (i = 0; trace_options[i]; i++) {
3500 if (strcmp(cmp, trace_options[i]) == 0) {
3501 ret = set_tracer_flag(tr, 1 << i, !neg);
3502 break;
3503 }
3504 }
3505
3506 /* If no option could be set, test the specific tracer options */
3507 if (!trace_options[i])
3508 ret = set_tracer_option(tr, cmp, neg);
3509
3510 mutex_unlock(&trace_types_lock);
3511
3512 return ret;
3513}
3514
3515static ssize_t
3516tracing_trace_options_write(struct file *filp, const char __user *ubuf,
3517 size_t cnt, loff_t *ppos)
3518{
3519 struct seq_file *m = filp->private_data;
3520 struct trace_array *tr = m->private;
3521 char buf[64];
3522 int ret;
3523
3524 if (cnt >= sizeof(buf))
3525 return -EINVAL;
3526
3527 if (copy_from_user(&buf, ubuf, cnt))
3528 return -EFAULT;
3529
3530 buf[cnt] = 0;
3531
3532 ret = trace_set_options(tr, buf);
3533 if (ret < 0)
3534 return ret;
3535
3536 *ppos += cnt;
3537
3538 return cnt;
3539}
3540
3541static int tracing_trace_options_open(struct inode *inode, struct file *file)
3542{
3543 struct trace_array *tr = inode->i_private;
3544 int ret;
3545
3546 if (tracing_disabled)
3547 return -ENODEV;
3548
3549 if (trace_array_get(tr) < 0)
3550 return -ENODEV;
3551
3552 ret = single_open(file, tracing_trace_options_show, inode->i_private);
3553 if (ret < 0)
3554 trace_array_put(tr);
3555
3556 return ret;
3557}
3558
3559static const struct file_operations tracing_iter_fops = {
3560 .open = tracing_trace_options_open,
3561 .read = seq_read,
3562 .llseek = seq_lseek,
3563 .release = tracing_single_release_tr,
3564 .write = tracing_trace_options_write,
3565};
3566
3567static const char readme_msg[] =
3568 "tracing mini-HOWTO:\n\n"
3569 "# echo 0 > tracing_on : quick way to disable tracing\n"
3570 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3571 " Important files:\n"
3572 " trace\t\t\t- The static contents of the buffer\n"
3573 "\t\t\t To clear the buffer write into this file: echo > trace\n"
3574 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3575 " current_tracer\t- function and latency tracers\n"
3576 " available_tracers\t- list of configured tracers for current_tracer\n"
3577 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
3578 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
3579 " trace_clock\t\t-change the clock used to order events\n"
3580 " local: Per cpu clock but may not be synced across CPUs\n"
3581 " global: Synced across CPUs but slows tracing down.\n"
3582 " counter: Not a clock, but just an increment\n"
3583 " uptime: Jiffy counter from time of boot\n"
3584 " perf: Same clock that perf events use\n"
3585#ifdef CONFIG_X86_64
3586 " x86-tsc: TSC cycle counter\n"
3587#endif
3588 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3589 " tracing_cpumask\t- Limit which CPUs to trace\n"
3590 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3591 "\t\t\t Remove sub-buffer with rmdir\n"
3592 " trace_options\t\t- Set format or modify how tracing happens\n"
3593 "\t\t\t Disable an option by adding a suffix 'no' to the\n"
3594 "\t\t\t option name\n"
3595#ifdef CONFIG_DYNAMIC_FTRACE
3596 "\n available_filter_functions - list of functions that can be filtered on\n"
3597 " set_ftrace_filter\t- echo function name in here to only trace these\n"
3598 "\t\t\t functions\n"
3599 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3600 "\t modules: Can select a group via module\n"
3601 "\t Format: :mod:<module-name>\n"
3602 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
3603 "\t triggers: a command to perform when function is hit\n"
3604 "\t Format: <function>:<trigger>[:count]\n"
3605 "\t trigger: traceon, traceoff\n"
3606 "\t\t enable_event:<system>:<event>\n"
3607 "\t\t disable_event:<system>:<event>\n"
3608#ifdef CONFIG_STACKTRACE
3609 "\t\t stacktrace\n"
3610#endif
3611#ifdef CONFIG_TRACER_SNAPSHOT
3612 "\t\t snapshot\n"
3613#endif
3614 "\t\t dump\n"
3615 "\t\t cpudump\n"
3616 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
3617 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
3618 "\t The first one will disable tracing every time do_fault is hit\n"
3619 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
3620 "\t The first time do trap is hit and it disables tracing, the\n"
3621 "\t counter will decrement to 2. If tracing is already disabled,\n"
3622 "\t the counter will not decrement. It only decrements when the\n"
3623 "\t trigger did work\n"
3624 "\t To remove trigger without count:\n"
3625 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
3626 "\t To remove trigger with a count:\n"
3627 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3628 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
3629 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3630 "\t modules: Can select a group via module command :mod:\n"
3631 "\t Does not accept triggers\n"
3632#endif /* CONFIG_DYNAMIC_FTRACE */
3633#ifdef CONFIG_FUNCTION_TRACER
3634 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
3635 "\t\t (function)\n"
3636#endif
3637#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3638 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3639 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3640#endif
3641#ifdef CONFIG_TRACER_SNAPSHOT
3642 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
3643 "\t\t\t snapshot buffer. Read the contents for more\n"
3644 "\t\t\t information\n"
3645#endif
3646#ifdef CONFIG_STACK_TRACER
3647 " stack_trace\t\t- Shows the max stack trace when active\n"
3648 " stack_max_size\t- Shows current max stack size that was traced\n"
3649 "\t\t\t Write into this file to reset the max size (trigger a\n"
3650 "\t\t\t new trace)\n"
3651#ifdef CONFIG_DYNAMIC_FTRACE
3652 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
3653 "\t\t\t traces\n"
3654#endif
3655#endif /* CONFIG_STACK_TRACER */
3656 " events/\t\t- Directory containing all trace event subsystems:\n"
3657 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
3658 " events/<system>/\t- Directory containing all trace events for <system>:\n"
3659 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
3660 "\t\t\t events\n"
3661 " filter\t\t- If set, only events passing filter are traced\n"
3662 " events/<system>/<event>/\t- Directory containing control files for\n"
3663 "\t\t\t <event>:\n"
3664 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
3665 " filter\t\t- If set, only events passing filter are traced\n"
3666 " trigger\t\t- If set, a command to perform when event is hit\n"
3667 "\t Format: <trigger>[:count][if <filter>]\n"
3668 "\t trigger: traceon, traceoff\n"
3669 "\t enable_event:<system>:<event>\n"
3670 "\t disable_event:<system>:<event>\n"
3671#ifdef CONFIG_STACKTRACE
3672 "\t\t stacktrace\n"
3673#endif
3674#ifdef CONFIG_TRACER_SNAPSHOT
3675 "\t\t snapshot\n"
3676#endif
3677 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
3678 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
3679 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
3680 "\t events/block/block_unplug/trigger\n"
3681 "\t The first disables tracing every time block_unplug is hit.\n"
3682 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
3683 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
3684 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
3685 "\t Like function triggers, the counter is only decremented if it\n"
3686 "\t enabled or disabled tracing.\n"
3687 "\t To remove a trigger without a count:\n"
3688 "\t echo '!<trigger> > <system>/<event>/trigger\n"
3689 "\t To remove a trigger with a count:\n"
3690 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
3691 "\t Filters can be ignored when removing a trigger.\n"
3692;
3693
3694static ssize_t
3695tracing_readme_read(struct file *filp, char __user *ubuf,
3696 size_t cnt, loff_t *ppos)
3697{
3698 return simple_read_from_buffer(ubuf, cnt, ppos,
3699 readme_msg, strlen(readme_msg));
3700}
3701
3702static const struct file_operations tracing_readme_fops = {
3703 .open = tracing_open_generic,
3704 .read = tracing_readme_read,
3705 .llseek = generic_file_llseek,
3706};
3707
3708static ssize_t
3709tracing_saved_cmdlines_read(struct file *file, char __user *ubuf,
3710 size_t cnt, loff_t *ppos)
3711{
3712 char *buf_comm;
3713 char *file_buf;
3714 char *buf;
3715 int len = 0;
3716 int pid;
3717 int i;
3718
3719 file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL);
3720 if (!file_buf)
3721 return -ENOMEM;
3722
3723 buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL);
3724 if (!buf_comm) {
3725 kfree(file_buf);
3726 return -ENOMEM;
3727 }
3728
3729 buf = file_buf;
3730
3731 for (i = 0; i < SAVED_CMDLINES; i++) {
3732 int r;
3733
3734 pid = map_cmdline_to_pid[i];
3735 if (pid == -1 || pid == NO_CMDLINE_MAP)
3736 continue;
3737
3738 trace_find_cmdline(pid, buf_comm);
3739 r = sprintf(buf, "%d %s\n", pid, buf_comm);
3740 buf += r;
3741 len += r;
3742 }
3743
3744 len = simple_read_from_buffer(ubuf, cnt, ppos,
3745 file_buf, len);
3746
3747 kfree(file_buf);
3748 kfree(buf_comm);
3749
3750 return len;
3751}
3752
3753static const struct file_operations tracing_saved_cmdlines_fops = {
3754 .open = tracing_open_generic,
3755 .read = tracing_saved_cmdlines_read,
3756 .llseek = generic_file_llseek,
3757};
3758
3759static ssize_t
3760tracing_set_trace_read(struct file *filp, char __user *ubuf,
3761 size_t cnt, loff_t *ppos)
3762{
3763 struct trace_array *tr = filp->private_data;
3764 char buf[MAX_TRACER_SIZE+2];
3765 int r;
3766
3767 mutex_lock(&trace_types_lock);
3768 r = sprintf(buf, "%s\n", tr->current_trace->name);
3769 mutex_unlock(&trace_types_lock);
3770
3771 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3772}
3773
3774int tracer_init(struct tracer *t, struct trace_array *tr)
3775{
3776 tracing_reset_online_cpus(&tr->trace_buffer);
3777 return t->init(tr);
3778}
3779
3780static void set_buffer_entries(struct trace_buffer *buf, unsigned long val)
3781{
3782 int cpu;
3783
3784 for_each_tracing_cpu(cpu)
3785 per_cpu_ptr(buf->data, cpu)->entries = val;
3786}
3787
3788#ifdef CONFIG_TRACER_MAX_TRACE
3789/* resize @tr's buffer to the size of @size_tr's entries */
3790static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
3791 struct trace_buffer *size_buf, int cpu_id)
3792{
3793 int cpu, ret = 0;
3794
3795 if (cpu_id == RING_BUFFER_ALL_CPUS) {
3796 for_each_tracing_cpu(cpu) {
3797 ret = ring_buffer_resize(trace_buf->buffer,
3798 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
3799 if (ret < 0)
3800 break;
3801 per_cpu_ptr(trace_buf->data, cpu)->entries =
3802 per_cpu_ptr(size_buf->data, cpu)->entries;
3803 }
3804 } else {
3805 ret = ring_buffer_resize(trace_buf->buffer,
3806 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
3807 if (ret == 0)
3808 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
3809 per_cpu_ptr(size_buf->data, cpu_id)->entries;
3810 }
3811
3812 return ret;
3813}
3814#endif /* CONFIG_TRACER_MAX_TRACE */
3815
3816static int __tracing_resize_ring_buffer(struct trace_array *tr,
3817 unsigned long size, int cpu)
3818{
3819 int ret;
3820
3821 /*
3822 * If kernel or user changes the size of the ring buffer
3823 * we use the size that was given, and we can forget about
3824 * expanding it later.
3825 */
3826 ring_buffer_expanded = true;
3827
3828 /* May be called before buffers are initialized */
3829 if (!tr->trace_buffer.buffer)
3830 return 0;
3831
3832 ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu);
3833 if (ret < 0)
3834 return ret;
3835
3836#ifdef CONFIG_TRACER_MAX_TRACE
3837 if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
3838 !tr->current_trace->use_max_tr)
3839 goto out;
3840
3841 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
3842 if (ret < 0) {
3843 int r = resize_buffer_duplicate_size(&tr->trace_buffer,
3844 &tr->trace_buffer, cpu);
3845 if (r < 0) {
3846 /*
3847 * AARGH! We are left with different
3848 * size max buffer!!!!
3849 * The max buffer is our "snapshot" buffer.
3850 * When a tracer needs a snapshot (one of the
3851 * latency tracers), it swaps the max buffer
3852 * with the saved snap shot. We succeeded to
3853 * update the size of the main buffer, but failed to
3854 * update the size of the max buffer. But when we tried
3855 * to reset the main buffer to the original size, we
3856 * failed there too. This is very unlikely to
3857 * happen, but if it does, warn and kill all
3858 * tracing.
3859 */
3860 WARN_ON(1);
3861 tracing_disabled = 1;
3862 }
3863 return ret;
3864 }
3865
3866 if (cpu == RING_BUFFER_ALL_CPUS)
3867 set_buffer_entries(&tr->max_buffer, size);
3868 else
3869 per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
3870
3871 out:
3872#endif /* CONFIG_TRACER_MAX_TRACE */
3873
3874 if (cpu == RING_BUFFER_ALL_CPUS)
3875 set_buffer_entries(&tr->trace_buffer, size);
3876 else
3877 per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size;
3878
3879 return ret;
3880}
3881
3882static ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
3883 unsigned long size, int cpu_id)
3884{
3885 int ret = size;
3886
3887 mutex_lock(&trace_types_lock);
3888
3889 if (cpu_id != RING_BUFFER_ALL_CPUS) {
3890 /* make sure, this cpu is enabled in the mask */
3891 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
3892 ret = -EINVAL;
3893 goto out;
3894 }
3895 }
3896
3897 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
3898 if (ret < 0)
3899 ret = -ENOMEM;
3900
3901out:
3902 mutex_unlock(&trace_types_lock);
3903
3904 return ret;
3905}
3906
3907
3908/**
3909 * tracing_update_buffers - used by tracing facility to expand ring buffers
3910 *
3911 * To save on memory when the tracing is never used on a system with it
3912 * configured in. The ring buffers are set to a minimum size. But once
3913 * a user starts to use the tracing facility, then they need to grow
3914 * to their default size.
3915 *
3916 * This function is to be called when a tracer is about to be used.
3917 */
3918int tracing_update_buffers(void)
3919{
3920 int ret = 0;
3921
3922 mutex_lock(&trace_types_lock);
3923 if (!ring_buffer_expanded)
3924 ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
3925 RING_BUFFER_ALL_CPUS);
3926 mutex_unlock(&trace_types_lock);
3927
3928 return ret;
3929}
3930
3931struct trace_option_dentry;
3932
3933static struct trace_option_dentry *
3934create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
3935
3936static void
3937destroy_trace_option_files(struct trace_option_dentry *topts);
3938
3939/*
3940 * Used to clear out the tracer before deletion of an instance.
3941 * Must have trace_types_lock held.
3942 */
3943static void tracing_set_nop(struct trace_array *tr)
3944{
3945 if (tr->current_trace == &nop_trace)
3946 return;
3947
3948 tr->current_trace->enabled--;
3949
3950 if (tr->current_trace->reset)
3951 tr->current_trace->reset(tr);
3952
3953 tr->current_trace = &nop_trace;
3954}
3955
3956static int tracing_set_tracer(struct trace_array *tr, const char *buf)
3957{
3958 static struct trace_option_dentry *topts;
3959 struct tracer *t;
3960#ifdef CONFIG_TRACER_MAX_TRACE
3961 bool had_max_tr;
3962#endif
3963 int ret = 0;
3964
3965 mutex_lock(&trace_types_lock);
3966
3967 if (!ring_buffer_expanded) {
3968 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
3969 RING_BUFFER_ALL_CPUS);
3970 if (ret < 0)
3971 goto out;
3972 ret = 0;
3973 }
3974
3975 for (t = trace_types; t; t = t->next) {
3976 if (strcmp(t->name, buf) == 0)
3977 break;
3978 }
3979 if (!t) {
3980 ret = -EINVAL;
3981 goto out;
3982 }
3983 if (t == tr->current_trace)
3984 goto out;
3985
3986 /* Some tracers are only allowed for the top level buffer */
3987 if (!trace_ok_for_array(t, tr)) {
3988 ret = -EINVAL;
3989 goto out;
3990 }
3991
3992 trace_branch_disable();
3993
3994 tr->current_trace->enabled--;
3995
3996 if (tr->current_trace->reset)
3997 tr->current_trace->reset(tr);
3998
3999 /* Current trace needs to be nop_trace before synchronize_sched */
4000 tr->current_trace = &nop_trace;
4001
4002#ifdef CONFIG_TRACER_MAX_TRACE
4003 had_max_tr = tr->allocated_snapshot;
4004
4005 if (had_max_tr && !t->use_max_tr) {
4006 /*
4007 * We need to make sure that the update_max_tr sees that
4008 * current_trace changed to nop_trace to keep it from
4009 * swapping the buffers after we resize it.
4010 * The update_max_tr is called from interrupts disabled
4011 * so a synchronized_sched() is sufficient.
4012 */
4013 synchronize_sched();
4014 free_snapshot(tr);
4015 }
4016#endif
4017 /* Currently, only the top instance has options */
4018 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
4019 destroy_trace_option_files(topts);
4020 topts = create_trace_option_files(tr, t);
4021 }
4022
4023#ifdef CONFIG_TRACER_MAX_TRACE
4024 if (t->use_max_tr && !had_max_tr) {
4025 ret = alloc_snapshot(tr);
4026 if (ret < 0)
4027 goto out;
4028 }
4029#endif
4030
4031 if (t->init) {
4032 ret = tracer_init(t, tr);
4033 if (ret)
4034 goto out;
4035 }
4036
4037 tr->current_trace = t;
4038 tr->current_trace->enabled++;
4039 trace_branch_enable(tr);
4040 out:
4041 mutex_unlock(&trace_types_lock);
4042
4043 return ret;
4044}
4045
4046static ssize_t
4047tracing_set_trace_write(struct file *filp, const char __user *ubuf,
4048 size_t cnt, loff_t *ppos)
4049{
4050 struct trace_array *tr = filp->private_data;
4051 char buf[MAX_TRACER_SIZE+1];
4052 int i;
4053 size_t ret;
4054 int err;
4055
4056 ret = cnt;
4057
4058 if (cnt > MAX_TRACER_SIZE)
4059 cnt = MAX_TRACER_SIZE;
4060
4061 if (copy_from_user(&buf, ubuf, cnt))
4062 return -EFAULT;
4063
4064 buf[cnt] = 0;
4065
4066 /* strip ending whitespace. */
4067 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
4068 buf[i] = 0;
4069
4070 err = tracing_set_tracer(tr, buf);
4071 if (err)
4072 return err;
4073
4074 *ppos += ret;
4075
4076 return ret;
4077}
4078
4079static ssize_t
4080tracing_max_lat_read(struct file *filp, char __user *ubuf,
4081 size_t cnt, loff_t *ppos)
4082{
4083 unsigned long *ptr = filp->private_data;
4084 char buf[64];
4085 int r;
4086
4087 r = snprintf(buf, sizeof(buf), "%ld\n",
4088 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
4089 if (r > sizeof(buf))
4090 r = sizeof(buf);
4091 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4092}
4093
4094static ssize_t
4095tracing_max_lat_write(struct file *filp, const char __user *ubuf,
4096 size_t cnt, loff_t *ppos)
4097{
4098 unsigned long *ptr = filp->private_data;
4099 unsigned long val;
4100 int ret;
4101
4102 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4103 if (ret)
4104 return ret;
4105
4106 *ptr = val * 1000;
4107
4108 return cnt;
4109}
4110
4111static int tracing_open_pipe(struct inode *inode, struct file *filp)
4112{
4113 struct trace_array *tr = inode->i_private;
4114 struct trace_iterator *iter;
4115 int ret = 0;
4116
4117 if (tracing_disabled)
4118 return -ENODEV;
4119
4120 if (trace_array_get(tr) < 0)
4121 return -ENODEV;
4122
4123 mutex_lock(&trace_types_lock);
4124
4125 /* create a buffer to store the information to pass to userspace */
4126 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4127 if (!iter) {
4128 ret = -ENOMEM;
4129 __trace_array_put(tr);
4130 goto out;
4131 }
4132
4133 /*
4134 * We make a copy of the current tracer to avoid concurrent
4135 * changes on it while we are reading.
4136 */
4137 iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
4138 if (!iter->trace) {
4139 ret = -ENOMEM;
4140 goto fail;
4141 }
4142 *iter->trace = *tr->current_trace;
4143
4144 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
4145 ret = -ENOMEM;
4146 goto fail;
4147 }
4148
4149 /* trace pipe does not show start of buffer */
4150 cpumask_setall(iter->started);
4151
4152 if (trace_flags & TRACE_ITER_LATENCY_FMT)
4153 iter->iter_flags |= TRACE_FILE_LAT_FMT;
4154
4155 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4156 if (trace_clocks[tr->clock_id].in_ns)
4157 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4158
4159 iter->tr = tr;
4160 iter->trace_buffer = &tr->trace_buffer;
4161 iter->cpu_file = tracing_get_cpu(inode);
4162 mutex_init(&iter->mutex);
4163 filp->private_data = iter;
4164
4165 if (iter->trace->pipe_open)
4166 iter->trace->pipe_open(iter);
4167
4168 nonseekable_open(inode, filp);
4169out:
4170 mutex_unlock(&trace_types_lock);
4171 return ret;
4172
4173fail:
4174 kfree(iter->trace);
4175 kfree(iter);
4176 __trace_array_put(tr);
4177 mutex_unlock(&trace_types_lock);
4178 return ret;
4179}
4180
4181static int tracing_release_pipe(struct inode *inode, struct file *file)
4182{
4183 struct trace_iterator *iter = file->private_data;
4184 struct trace_array *tr = inode->i_private;
4185
4186 mutex_lock(&trace_types_lock);
4187
4188 if (iter->trace->pipe_close)
4189 iter->trace->pipe_close(iter);
4190
4191 mutex_unlock(&trace_types_lock);
4192
4193 free_cpumask_var(iter->started);
4194 mutex_destroy(&iter->mutex);
4195 kfree(iter->trace);
4196 kfree(iter);
4197
4198 trace_array_put(tr);
4199
4200 return 0;
4201}
4202
4203static unsigned int
4204trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
4205{
4206 /* Iterators are static, they should be filled or empty */
4207 if (trace_buffer_iter(iter, iter->cpu_file))
4208 return POLLIN | POLLRDNORM;
4209
4210 if (trace_flags & TRACE_ITER_BLOCK)
4211 /*
4212 * Always select as readable when in blocking mode
4213 */
4214 return POLLIN | POLLRDNORM;
4215 else
4216 return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file,
4217 filp, poll_table);
4218}
4219
4220static unsigned int
4221tracing_poll_pipe(struct file *filp, poll_table *poll_table)
4222{
4223 struct trace_iterator *iter = filp->private_data;
4224
4225 return trace_poll(iter, filp, poll_table);
4226}
4227
4228/*
4229 * This is a make-shift waitqueue.
4230 * A tracer might use this callback on some rare cases:
4231 *
4232 * 1) the current tracer might hold the runqueue lock when it wakes up
4233 * a reader, hence a deadlock (sched, function, and function graph tracers)
4234 * 2) the function tracers, trace all functions, we don't want
4235 * the overhead of calling wake_up and friends
4236 * (and tracing them too)
4237 *
4238 * Anyway, this is really very primitive wakeup.
4239 */
4240void poll_wait_pipe(struct trace_iterator *iter)
4241{
4242 set_current_state(TASK_INTERRUPTIBLE);
4243 /* sleep for 100 msecs, and try again. */
4244 schedule_timeout(HZ / 10);
4245}
4246
4247/* Must be called with trace_types_lock mutex held. */
4248static int tracing_wait_pipe(struct file *filp)
4249{
4250 struct trace_iterator *iter = filp->private_data;
4251
4252 while (trace_empty(iter)) {
4253
4254 if ((filp->f_flags & O_NONBLOCK)) {
4255 return -EAGAIN;
4256 }
4257
4258 mutex_unlock(&iter->mutex);
4259
4260 iter->trace->wait_pipe(iter);
4261
4262 mutex_lock(&iter->mutex);
4263
4264 if (signal_pending(current))
4265 return -EINTR;
4266
4267 /*
4268 * We block until we read something and tracing is disabled.
4269 * We still block if tracing is disabled, but we have never
4270 * read anything. This allows a user to cat this file, and
4271 * then enable tracing. But after we have read something,
4272 * we give an EOF when tracing is again disabled.
4273 *
4274 * iter->pos will be 0 if we haven't read anything.
4275 */
4276 if (!tracing_is_on() && iter->pos)
4277 break;
4278 }
4279
4280 return 1;
4281}
4282
4283/*
4284 * Consumer reader.
4285 */
4286static ssize_t
4287tracing_read_pipe(struct file *filp, char __user *ubuf,
4288 size_t cnt, loff_t *ppos)
4289{
4290 struct trace_iterator *iter = filp->private_data;
4291 struct trace_array *tr = iter->tr;
4292 ssize_t sret;
4293
4294 /* return any leftover data */
4295 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
4296 if (sret != -EBUSY)
4297 return sret;
4298
4299 trace_seq_init(&iter->seq);
4300
4301 /* copy the tracer to avoid using a global lock all around */
4302 mutex_lock(&trace_types_lock);
4303 if (unlikely(iter->trace->name != tr->current_trace->name))
4304 *iter->trace = *tr->current_trace;
4305 mutex_unlock(&trace_types_lock);
4306
4307 /*
4308 * Avoid more than one consumer on a single file descriptor
4309 * This is just a matter of traces coherency, the ring buffer itself
4310 * is protected.
4311 */
4312 mutex_lock(&iter->mutex);
4313 if (iter->trace->read) {
4314 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
4315 if (sret)
4316 goto out;
4317 }
4318
4319waitagain:
4320 sret = tracing_wait_pipe(filp);
4321 if (sret <= 0)
4322 goto out;
4323
4324 /* stop when tracing is finished */
4325 if (trace_empty(iter)) {
4326 sret = 0;
4327 goto out;
4328 }
4329
4330 if (cnt >= PAGE_SIZE)
4331 cnt = PAGE_SIZE - 1;
4332
4333 /* reset all but tr, trace, and overruns */
4334 memset(&iter->seq, 0,
4335 sizeof(struct trace_iterator) -
4336 offsetof(struct trace_iterator, seq));
4337 cpumask_clear(iter->started);
4338 iter->pos = -1;
4339
4340 trace_event_read_lock();
4341 trace_access_lock(iter->cpu_file);
4342 while (trace_find_next_entry_inc(iter) != NULL) {
4343 enum print_line_t ret;
4344 int len = iter->seq.len;
4345
4346 ret = print_trace_line(iter);
4347 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4348 /* don't print partial lines */
4349 iter->seq.len = len;
4350 break;
4351 }
4352 if (ret != TRACE_TYPE_NO_CONSUME)
4353 trace_consume(iter);
4354
4355 if (iter->seq.len >= cnt)
4356 break;
4357
4358 /*
4359 * Setting the full flag means we reached the trace_seq buffer
4360 * size and we should leave by partial output condition above.
4361 * One of the trace_seq_* functions is not used properly.
4362 */
4363 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
4364 iter->ent->type);
4365 }
4366 trace_access_unlock(iter->cpu_file);
4367 trace_event_read_unlock();
4368
4369 /* Now copy what we have to the user */
4370 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
4371 if (iter->seq.readpos >= iter->seq.len)
4372 trace_seq_init(&iter->seq);
4373
4374 /*
4375 * If there was nothing to send to user, in spite of consuming trace
4376 * entries, go back to wait for more entries.
4377 */
4378 if (sret == -EBUSY)
4379 goto waitagain;
4380
4381out:
4382 mutex_unlock(&iter->mutex);
4383
4384 return sret;
4385}
4386
4387static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
4388 unsigned int idx)
4389{
4390 __free_page(spd->pages[idx]);
4391}
4392
4393static const struct pipe_buf_operations tracing_pipe_buf_ops = {
4394 .can_merge = 0,
4395 .confirm = generic_pipe_buf_confirm,
4396 .release = generic_pipe_buf_release,
4397 .steal = generic_pipe_buf_steal,
4398 .get = generic_pipe_buf_get,
4399};
4400
4401static size_t
4402tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
4403{
4404 size_t count;
4405 int ret;
4406
4407 /* Seq buffer is page-sized, exactly what we need. */
4408 for (;;) {
4409 count = iter->seq.len;
4410 ret = print_trace_line(iter);
4411 count = iter->seq.len - count;
4412 if (rem < count) {
4413 rem = 0;
4414 iter->seq.len -= count;
4415 break;
4416 }
4417 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4418 iter->seq.len -= count;
4419 break;
4420 }
4421
4422 if (ret != TRACE_TYPE_NO_CONSUME)
4423 trace_consume(iter);
4424 rem -= count;
4425 if (!trace_find_next_entry_inc(iter)) {
4426 rem = 0;
4427 iter->ent = NULL;
4428 break;
4429 }
4430 }
4431
4432 return rem;
4433}
4434
4435static ssize_t tracing_splice_read_pipe(struct file *filp,
4436 loff_t *ppos,
4437 struct pipe_inode_info *pipe,
4438 size_t len,
4439 unsigned int flags)
4440{
4441 struct page *pages_def[PIPE_DEF_BUFFERS];
4442 struct partial_page partial_def[PIPE_DEF_BUFFERS];
4443 struct trace_iterator *iter = filp->private_data;
4444 struct splice_pipe_desc spd = {
4445 .pages = pages_def,
4446 .partial = partial_def,
4447 .nr_pages = 0, /* This gets updated below. */
4448 .nr_pages_max = PIPE_DEF_BUFFERS,
4449 .flags = flags,
4450 .ops = &tracing_pipe_buf_ops,
4451 .spd_release = tracing_spd_release_pipe,
4452 };
4453 struct trace_array *tr = iter->tr;
4454 ssize_t ret;
4455 size_t rem;
4456 unsigned int i;
4457
4458 if (splice_grow_spd(pipe, &spd))
4459 return -ENOMEM;
4460
4461 /* copy the tracer to avoid using a global lock all around */
4462 mutex_lock(&trace_types_lock);
4463 if (unlikely(iter->trace->name != tr->current_trace->name))
4464 *iter->trace = *tr->current_trace;
4465 mutex_unlock(&trace_types_lock);
4466
4467 mutex_lock(&iter->mutex);
4468
4469 if (iter->trace->splice_read) {
4470 ret = iter->trace->splice_read(iter, filp,
4471 ppos, pipe, len, flags);
4472 if (ret)
4473 goto out_err;
4474 }
4475
4476 ret = tracing_wait_pipe(filp);
4477 if (ret <= 0)
4478 goto out_err;
4479
4480 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
4481 ret = -EFAULT;
4482 goto out_err;
4483 }
4484
4485 trace_event_read_lock();
4486 trace_access_lock(iter->cpu_file);
4487
4488 /* Fill as many pages as possible. */
4489 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
4490 spd.pages[i] = alloc_page(GFP_KERNEL);
4491 if (!spd.pages[i])
4492 break;
4493
4494 rem = tracing_fill_pipe_page(rem, iter);
4495
4496 /* Copy the data into the page, so we can start over. */
4497 ret = trace_seq_to_buffer(&iter->seq,
4498 page_address(spd.pages[i]),
4499 iter->seq.len);
4500 if (ret < 0) {
4501 __free_page(spd.pages[i]);
4502 break;
4503 }
4504 spd.partial[i].offset = 0;
4505 spd.partial[i].len = iter->seq.len;
4506
4507 trace_seq_init(&iter->seq);
4508 }
4509
4510 trace_access_unlock(iter->cpu_file);
4511 trace_event_read_unlock();
4512 mutex_unlock(&iter->mutex);
4513
4514 spd.nr_pages = i;
4515
4516 ret = splice_to_pipe(pipe, &spd);
4517out:
4518 splice_shrink_spd(&spd);
4519 return ret;
4520
4521out_err:
4522 mutex_unlock(&iter->mutex);
4523 goto out;
4524}
4525
4526static ssize_t
4527tracing_entries_read(struct file *filp, char __user *ubuf,
4528 size_t cnt, loff_t *ppos)
4529{
4530 struct inode *inode = file_inode(filp);
4531 struct trace_array *tr = inode->i_private;
4532 int cpu = tracing_get_cpu(inode);
4533 char buf[64];
4534 int r = 0;
4535 ssize_t ret;
4536
4537 mutex_lock(&trace_types_lock);
4538
4539 if (cpu == RING_BUFFER_ALL_CPUS) {
4540 int cpu, buf_size_same;
4541 unsigned long size;
4542
4543 size = 0;
4544 buf_size_same = 1;
4545 /* check if all cpu sizes are same */
4546 for_each_tracing_cpu(cpu) {
4547 /* fill in the size from first enabled cpu */
4548 if (size == 0)
4549 size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries;
4550 if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) {
4551 buf_size_same = 0;
4552 break;
4553 }
4554 }
4555
4556 if (buf_size_same) {
4557 if (!ring_buffer_expanded)
4558 r = sprintf(buf, "%lu (expanded: %lu)\n",
4559 size >> 10,
4560 trace_buf_size >> 10);
4561 else
4562 r = sprintf(buf, "%lu\n", size >> 10);
4563 } else
4564 r = sprintf(buf, "X\n");
4565 } else
4566 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
4567
4568 mutex_unlock(&trace_types_lock);
4569
4570 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4571 return ret;
4572}
4573
4574static ssize_t
4575tracing_entries_write(struct file *filp, const char __user *ubuf,
4576 size_t cnt, loff_t *ppos)
4577{
4578 struct inode *inode = file_inode(filp);
4579 struct trace_array *tr = inode->i_private;
4580 unsigned long val;
4581 int ret;
4582
4583 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4584 if (ret)
4585 return ret;
4586
4587 /* must have at least 1 entry */
4588 if (!val)
4589 return -EINVAL;
4590
4591 /* value is in KB */
4592 val <<= 10;
4593 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
4594 if (ret < 0)
4595 return ret;
4596
4597 *ppos += cnt;
4598
4599 return cnt;
4600}
4601
4602static ssize_t
4603tracing_total_entries_read(struct file *filp, char __user *ubuf,
4604 size_t cnt, loff_t *ppos)
4605{
4606 struct trace_array *tr = filp->private_data;
4607 char buf[64];
4608 int r, cpu;
4609 unsigned long size = 0, expanded_size = 0;
4610
4611 mutex_lock(&trace_types_lock);
4612 for_each_tracing_cpu(cpu) {
4613 size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10;
4614 if (!ring_buffer_expanded)
4615 expanded_size += trace_buf_size >> 10;
4616 }
4617 if (ring_buffer_expanded)
4618 r = sprintf(buf, "%lu\n", size);
4619 else
4620 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
4621 mutex_unlock(&trace_types_lock);
4622
4623 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4624}
4625
4626static ssize_t
4627tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
4628 size_t cnt, loff_t *ppos)
4629{
4630 /*
4631 * There is no need to read what the user has written, this function
4632 * is just to make sure that there is no error when "echo" is used
4633 */
4634
4635 *ppos += cnt;
4636
4637 return cnt;
4638}
4639
4640static int
4641tracing_free_buffer_release(struct inode *inode, struct file *filp)
4642{
4643 struct trace_array *tr = inode->i_private;
4644
4645 /* disable tracing ? */
4646 if (trace_flags & TRACE_ITER_STOP_ON_FREE)
4647 tracer_tracing_off(tr);
4648 /* resize the ring buffer to 0 */
4649 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
4650
4651 trace_array_put(tr);
4652
4653 return 0;
4654}
4655
4656static ssize_t
4657tracing_mark_write(struct file *filp, const char __user *ubuf,
4658 size_t cnt, loff_t *fpos)
4659{
4660 unsigned long addr = (unsigned long)ubuf;
4661 struct trace_array *tr = filp->private_data;
4662 struct ring_buffer_event *event;
4663 struct ring_buffer *buffer;
4664 struct print_entry *entry;
4665 unsigned long irq_flags;
4666 struct page *pages[2];
4667 void *map_page[2];
4668 int nr_pages = 1;
4669 ssize_t written;
4670 int offset;
4671 int size;
4672 int len;
4673 int ret;
4674 int i;
4675
4676 if (tracing_disabled)
4677 return -EINVAL;
4678
4679 if (!(trace_flags & TRACE_ITER_MARKERS))
4680 return -EINVAL;
4681
4682 if (cnt > TRACE_BUF_SIZE)
4683 cnt = TRACE_BUF_SIZE;
4684
4685 /*
4686 * Userspace is injecting traces into the kernel trace buffer.
4687 * We want to be as non intrusive as possible.
4688 * To do so, we do not want to allocate any special buffers
4689 * or take any locks, but instead write the userspace data
4690 * straight into the ring buffer.
4691 *
4692 * First we need to pin the userspace buffer into memory,
4693 * which, most likely it is, because it just referenced it.
4694 * But there's no guarantee that it is. By using get_user_pages_fast()
4695 * and kmap_atomic/kunmap_atomic() we can get access to the
4696 * pages directly. We then write the data directly into the
4697 * ring buffer.
4698 */
4699 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
4700
4701 /* check if we cross pages */
4702 if ((addr & PAGE_MASK) != ((addr + cnt) & PAGE_MASK))
4703 nr_pages = 2;
4704
4705 offset = addr & (PAGE_SIZE - 1);
4706 addr &= PAGE_MASK;
4707
4708 ret = get_user_pages_fast(addr, nr_pages, 0, pages);
4709 if (ret < nr_pages) {
4710 while (--ret >= 0)
4711 put_page(pages[ret]);
4712 written = -EFAULT;
4713 goto out;
4714 }
4715
4716 for (i = 0; i < nr_pages; i++)
4717 map_page[i] = kmap_atomic(pages[i]);
4718
4719 local_save_flags(irq_flags);
4720 size = sizeof(*entry) + cnt + 2; /* possible \n added */
4721 buffer = tr->trace_buffer.buffer;
4722 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
4723 irq_flags, preempt_count());
4724 if (!event) {
4725 /* Ring buffer disabled, return as if not open for write */
4726 written = -EBADF;
4727 goto out_unlock;
4728 }
4729
4730 entry = ring_buffer_event_data(event);
4731 entry->ip = _THIS_IP_;
4732
4733 if (nr_pages == 2) {
4734 len = PAGE_SIZE - offset;
4735 memcpy(&entry->buf, map_page[0] + offset, len);
4736 memcpy(&entry->buf[len], map_page[1], cnt - len);
4737 } else
4738 memcpy(&entry->buf, map_page[0] + offset, cnt);
4739
4740 if (entry->buf[cnt - 1] != '\n') {
4741 entry->buf[cnt] = '\n';
4742 entry->buf[cnt + 1] = '\0';
4743 } else
4744 entry->buf[cnt] = '\0';
4745
4746 __buffer_unlock_commit(buffer, event);
4747
4748 written = cnt;
4749
4750 *fpos += written;
4751
4752 out_unlock:
4753 for (i = 0; i < nr_pages; i++){
4754 kunmap_atomic(map_page[i]);
4755 put_page(pages[i]);
4756 }
4757 out:
4758 return written;
4759}
4760
4761static int tracing_clock_show(struct seq_file *m, void *v)
4762{
4763 struct trace_array *tr = m->private;
4764 int i;
4765
4766 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
4767 seq_printf(m,
4768 "%s%s%s%s", i ? " " : "",
4769 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
4770 i == tr->clock_id ? "]" : "");
4771 seq_putc(m, '\n');
4772
4773 return 0;
4774}
4775
4776static int tracing_set_clock(struct trace_array *tr, const char *clockstr)
4777{
4778 int i;
4779
4780 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
4781 if (strcmp(trace_clocks[i].name, clockstr) == 0)
4782 break;
4783 }
4784 if (i == ARRAY_SIZE(trace_clocks))
4785 return -EINVAL;
4786
4787 mutex_lock(&trace_types_lock);
4788
4789 tr->clock_id = i;
4790
4791 ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func);
4792
4793 /*
4794 * New clock may not be consistent with the previous clock.
4795 * Reset the buffer so that it doesn't have incomparable timestamps.
4796 */
4797 tracing_reset_online_cpus(&tr->trace_buffer);
4798
4799#ifdef CONFIG_TRACER_MAX_TRACE
4800 if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
4801 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
4802 tracing_reset_online_cpus(&tr->max_buffer);
4803#endif
4804
4805 mutex_unlock(&trace_types_lock);
4806
4807 return 0;
4808}
4809
4810static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
4811 size_t cnt, loff_t *fpos)
4812{
4813 struct seq_file *m = filp->private_data;
4814 struct trace_array *tr = m->private;
4815 char buf[64];
4816 const char *clockstr;
4817 int ret;
4818
4819 if (cnt >= sizeof(buf))
4820 return -EINVAL;
4821
4822 if (copy_from_user(&buf, ubuf, cnt))
4823 return -EFAULT;
4824
4825 buf[cnt] = 0;
4826
4827 clockstr = strstrip(buf);
4828
4829 ret = tracing_set_clock(tr, clockstr);
4830 if (ret)
4831 return ret;
4832
4833 *fpos += cnt;
4834
4835 return cnt;
4836}
4837
4838static int tracing_clock_open(struct inode *inode, struct file *file)
4839{
4840 struct trace_array *tr = inode->i_private;
4841 int ret;
4842
4843 if (tracing_disabled)
4844 return -ENODEV;
4845
4846 if (trace_array_get(tr))
4847 return -ENODEV;
4848
4849 ret = single_open(file, tracing_clock_show, inode->i_private);
4850 if (ret < 0)
4851 trace_array_put(tr);
4852
4853 return ret;
4854}
4855
4856struct ftrace_buffer_info {
4857 struct trace_iterator iter;
4858 void *spare;
4859 unsigned int read;
4860};
4861
4862#ifdef CONFIG_TRACER_SNAPSHOT
4863static int tracing_snapshot_open(struct inode *inode, struct file *file)
4864{
4865 struct trace_array *tr = inode->i_private;
4866 struct trace_iterator *iter;
4867 struct seq_file *m;
4868 int ret = 0;
4869
4870 if (trace_array_get(tr) < 0)
4871 return -ENODEV;
4872
4873 if (file->f_mode & FMODE_READ) {
4874 iter = __tracing_open(inode, file, true);
4875 if (IS_ERR(iter))
4876 ret = PTR_ERR(iter);
4877 } else {
4878 /* Writes still need the seq_file to hold the private data */
4879 ret = -ENOMEM;
4880 m = kzalloc(sizeof(*m), GFP_KERNEL);
4881 if (!m)
4882 goto out;
4883 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4884 if (!iter) {
4885 kfree(m);
4886 goto out;
4887 }
4888 ret = 0;
4889
4890 iter->tr = tr;
4891 iter->trace_buffer = &tr->max_buffer;
4892 iter->cpu_file = tracing_get_cpu(inode);
4893 m->private = iter;
4894 file->private_data = m;
4895 }
4896out:
4897 if (ret < 0)
4898 trace_array_put(tr);
4899
4900 return ret;
4901}
4902
4903static ssize_t
4904tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
4905 loff_t *ppos)
4906{
4907 struct seq_file *m = filp->private_data;
4908 struct trace_iterator *iter = m->private;
4909 struct trace_array *tr = iter->tr;
4910 unsigned long val;
4911 int ret;
4912
4913 ret = tracing_update_buffers();
4914 if (ret < 0)
4915 return ret;
4916
4917 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4918 if (ret)
4919 return ret;
4920
4921 mutex_lock(&trace_types_lock);
4922
4923 if (tr->current_trace->use_max_tr) {
4924 ret = -EBUSY;
4925 goto out;
4926 }
4927
4928 switch (val) {
4929 case 0:
4930 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4931 ret = -EINVAL;
4932 break;
4933 }
4934 if (tr->allocated_snapshot)
4935 free_snapshot(tr);
4936 break;
4937 case 1:
4938/* Only allow per-cpu swap if the ring buffer supports it */
4939#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
4940 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4941 ret = -EINVAL;
4942 break;
4943 }
4944#endif
4945 if (!tr->allocated_snapshot) {
4946 ret = alloc_snapshot(tr);
4947 if (ret < 0)
4948 break;
4949 }
4950 local_irq_disable();
4951 /* Now, we're going to swap */
4952 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4953 update_max_tr(tr, current, smp_processor_id());
4954 else
4955 update_max_tr_single(tr, current, iter->cpu_file);
4956 local_irq_enable();
4957 break;
4958 default:
4959 if (tr->allocated_snapshot) {
4960 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4961 tracing_reset_online_cpus(&tr->max_buffer);
4962 else
4963 tracing_reset(&tr->max_buffer, iter->cpu_file);
4964 }
4965 break;
4966 }
4967
4968 if (ret >= 0) {
4969 *ppos += cnt;
4970 ret = cnt;
4971 }
4972out:
4973 mutex_unlock(&trace_types_lock);
4974 return ret;
4975}
4976
4977static int tracing_snapshot_release(struct inode *inode, struct file *file)
4978{
4979 struct seq_file *m = file->private_data;
4980 int ret;
4981
4982 ret = tracing_release(inode, file);
4983
4984 if (file->f_mode & FMODE_READ)
4985 return ret;
4986
4987 /* If write only, the seq_file is just a stub */
4988 if (m)
4989 kfree(m->private);
4990 kfree(m);
4991
4992 return 0;
4993}
4994
4995static int tracing_buffers_open(struct inode *inode, struct file *filp);
4996static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
4997 size_t count, loff_t *ppos);
4998static int tracing_buffers_release(struct inode *inode, struct file *file);
4999static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
5000 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
5001
5002static int snapshot_raw_open(struct inode *inode, struct file *filp)
5003{
5004 struct ftrace_buffer_info *info;
5005 int ret;
5006
5007 ret = tracing_buffers_open(inode, filp);
5008 if (ret < 0)
5009 return ret;
5010
5011 info = filp->private_data;
5012
5013 if (info->iter.trace->use_max_tr) {
5014 tracing_buffers_release(inode, filp);
5015 return -EBUSY;
5016 }
5017
5018 info->iter.snapshot = true;
5019 info->iter.trace_buffer = &info->iter.tr->max_buffer;
5020
5021 return ret;
5022}
5023
5024#endif /* CONFIG_TRACER_SNAPSHOT */
5025
5026
5027static const struct file_operations tracing_max_lat_fops = {
5028 .open = tracing_open_generic,
5029 .read = tracing_max_lat_read,
5030 .write = tracing_max_lat_write,
5031 .llseek = generic_file_llseek,
5032};
5033
5034static const struct file_operations set_tracer_fops = {
5035 .open = tracing_open_generic,
5036 .read = tracing_set_trace_read,
5037 .write = tracing_set_trace_write,
5038 .llseek = generic_file_llseek,
5039};
5040
5041static const struct file_operations tracing_pipe_fops = {
5042 .open = tracing_open_pipe,
5043 .poll = tracing_poll_pipe,
5044 .read = tracing_read_pipe,
5045 .splice_read = tracing_splice_read_pipe,
5046 .release = tracing_release_pipe,
5047 .llseek = no_llseek,
5048};
5049
5050static const struct file_operations tracing_entries_fops = {
5051 .open = tracing_open_generic_tr,
5052 .read = tracing_entries_read,
5053 .write = tracing_entries_write,
5054 .llseek = generic_file_llseek,
5055 .release = tracing_release_generic_tr,
5056};
5057
5058static const struct file_operations tracing_total_entries_fops = {
5059 .open = tracing_open_generic_tr,
5060 .read = tracing_total_entries_read,
5061 .llseek = generic_file_llseek,
5062 .release = tracing_release_generic_tr,
5063};
5064
5065static const struct file_operations tracing_free_buffer_fops = {
5066 .open = tracing_open_generic_tr,
5067 .write = tracing_free_buffer_write,
5068 .release = tracing_free_buffer_release,
5069};
5070
5071static const struct file_operations tracing_mark_fops = {
5072 .open = tracing_open_generic_tr,
5073 .write = tracing_mark_write,
5074 .llseek = generic_file_llseek,
5075 .release = tracing_release_generic_tr,
5076};
5077
5078static const struct file_operations trace_clock_fops = {
5079 .open = tracing_clock_open,
5080 .read = seq_read,
5081 .llseek = seq_lseek,
5082 .release = tracing_single_release_tr,
5083 .write = tracing_clock_write,
5084};
5085
5086#ifdef CONFIG_TRACER_SNAPSHOT
5087static const struct file_operations snapshot_fops = {
5088 .open = tracing_snapshot_open,
5089 .read = seq_read,
5090 .write = tracing_snapshot_write,
5091 .llseek = tracing_lseek,
5092 .release = tracing_snapshot_release,
5093};
5094
5095static const struct file_operations snapshot_raw_fops = {
5096 .open = snapshot_raw_open,
5097 .read = tracing_buffers_read,
5098 .release = tracing_buffers_release,
5099 .splice_read = tracing_buffers_splice_read,
5100 .llseek = no_llseek,
5101};
5102
5103#endif /* CONFIG_TRACER_SNAPSHOT */
5104
5105static int tracing_buffers_open(struct inode *inode, struct file *filp)
5106{
5107 struct trace_array *tr = inode->i_private;
5108 struct ftrace_buffer_info *info;
5109 int ret;
5110
5111 if (tracing_disabled)
5112 return -ENODEV;
5113
5114 if (trace_array_get(tr) < 0)
5115 return -ENODEV;
5116
5117 info = kzalloc(sizeof(*info), GFP_KERNEL);
5118 if (!info) {
5119 trace_array_put(tr);
5120 return -ENOMEM;
5121 }
5122
5123 mutex_lock(&trace_types_lock);
5124
5125 info->iter.tr = tr;
5126 info->iter.cpu_file = tracing_get_cpu(inode);
5127 info->iter.trace = tr->current_trace;
5128 info->iter.trace_buffer = &tr->trace_buffer;
5129 info->spare = NULL;
5130 /* Force reading ring buffer for first read */
5131 info->read = (unsigned int)-1;
5132
5133 filp->private_data = info;
5134
5135 mutex_unlock(&trace_types_lock);
5136
5137 ret = nonseekable_open(inode, filp);
5138 if (ret < 0)
5139 trace_array_put(tr);
5140
5141 return ret;
5142}
5143
5144static unsigned int
5145tracing_buffers_poll(struct file *filp, poll_table *poll_table)
5146{
5147 struct ftrace_buffer_info *info = filp->private_data;
5148 struct trace_iterator *iter = &info->iter;
5149
5150 return trace_poll(iter, filp, poll_table);
5151}
5152
5153static ssize_t
5154tracing_buffers_read(struct file *filp, char __user *ubuf,
5155 size_t count, loff_t *ppos)
5156{
5157 struct ftrace_buffer_info *info = filp->private_data;
5158 struct trace_iterator *iter = &info->iter;
5159 ssize_t ret;
5160 ssize_t size;
5161
5162 if (!count)
5163 return 0;
5164
5165 mutex_lock(&trace_types_lock);
5166
5167#ifdef CONFIG_TRACER_MAX_TRACE
5168 if (iter->snapshot && iter->tr->current_trace->use_max_tr) {
5169 size = -EBUSY;
5170 goto out_unlock;
5171 }
5172#endif
5173
5174 if (!info->spare)
5175 info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
5176 iter->cpu_file);
5177 size = -ENOMEM;
5178 if (!info->spare)
5179 goto out_unlock;
5180
5181 /* Do we have previous read data to read? */
5182 if (info->read < PAGE_SIZE)
5183 goto read;
5184
5185 again:
5186 trace_access_lock(iter->cpu_file);
5187 ret = ring_buffer_read_page(iter->trace_buffer->buffer,
5188 &info->spare,
5189 count,
5190 iter->cpu_file, 0);
5191 trace_access_unlock(iter->cpu_file);
5192
5193 if (ret < 0) {
5194 if (trace_empty(iter)) {
5195 if ((filp->f_flags & O_NONBLOCK)) {
5196 size = -EAGAIN;
5197 goto out_unlock;
5198 }
5199 mutex_unlock(&trace_types_lock);
5200 iter->trace->wait_pipe(iter);
5201 mutex_lock(&trace_types_lock);
5202 if (signal_pending(current)) {
5203 size = -EINTR;
5204 goto out_unlock;
5205 }
5206 goto again;
5207 }
5208 size = 0;
5209 goto out_unlock;
5210 }
5211
5212 info->read = 0;
5213 read:
5214 size = PAGE_SIZE - info->read;
5215 if (size > count)
5216 size = count;
5217
5218 ret = copy_to_user(ubuf, info->spare + info->read, size);
5219 if (ret == size) {
5220 size = -EFAULT;
5221 goto out_unlock;
5222 }
5223 size -= ret;
5224
5225 *ppos += size;
5226 info->read += size;
5227
5228 out_unlock:
5229 mutex_unlock(&trace_types_lock);
5230
5231 return size;
5232}
5233
5234static int tracing_buffers_release(struct inode *inode, struct file *file)
5235{
5236 struct ftrace_buffer_info *info = file->private_data;
5237 struct trace_iterator *iter = &info->iter;
5238
5239 mutex_lock(&trace_types_lock);
5240
5241 __trace_array_put(iter->tr);
5242
5243 if (info->spare)
5244 ring_buffer_free_read_page(iter->trace_buffer->buffer, info->spare);
5245 kfree(info);
5246
5247 mutex_unlock(&trace_types_lock);
5248
5249 return 0;
5250}
5251
5252struct buffer_ref {
5253 struct ring_buffer *buffer;
5254 void *page;
5255 int ref;
5256};
5257
5258static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
5259 struct pipe_buffer *buf)
5260{
5261 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
5262
5263 if (--ref->ref)
5264 return;
5265
5266 ring_buffer_free_read_page(ref->buffer, ref->page);
5267 kfree(ref);
5268 buf->private = 0;
5269}
5270
5271static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
5272 struct pipe_buffer *buf)
5273{
5274 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
5275
5276 ref->ref++;
5277}
5278
5279/* Pipe buffer operations for a buffer. */
5280static const struct pipe_buf_operations buffer_pipe_buf_ops = {
5281 .can_merge = 0,
5282 .confirm = generic_pipe_buf_confirm,
5283 .release = buffer_pipe_buf_release,
5284 .steal = generic_pipe_buf_steal,
5285 .get = buffer_pipe_buf_get,
5286};
5287
5288/*
5289 * Callback from splice_to_pipe(), if we need to release some pages
5290 * at the end of the spd in case we error'ed out in filling the pipe.
5291 */
5292static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
5293{
5294 struct buffer_ref *ref =
5295 (struct buffer_ref *)spd->partial[i].private;
5296
5297 if (--ref->ref)
5298 return;
5299
5300 ring_buffer_free_read_page(ref->buffer, ref->page);
5301 kfree(ref);
5302 spd->partial[i].private = 0;
5303}
5304
5305static ssize_t
5306tracing_buffers_splice_read(struct file *file, loff_t *ppos,
5307 struct pipe_inode_info *pipe, size_t len,
5308 unsigned int flags)
5309{
5310 struct ftrace_buffer_info *info = file->private_data;
5311 struct trace_iterator *iter = &info->iter;
5312 struct partial_page partial_def[PIPE_DEF_BUFFERS];
5313 struct page *pages_def[PIPE_DEF_BUFFERS];
5314 struct splice_pipe_desc spd = {
5315 .pages = pages_def,
5316 .partial = partial_def,
5317 .nr_pages_max = PIPE_DEF_BUFFERS,
5318 .flags = flags,
5319 .ops = &buffer_pipe_buf_ops,
5320 .spd_release = buffer_spd_release,
5321 };
5322 struct buffer_ref *ref;
5323 int entries, size, i;
5324 ssize_t ret;
5325
5326 mutex_lock(&trace_types_lock);
5327
5328#ifdef CONFIG_TRACER_MAX_TRACE
5329 if (iter->snapshot && iter->tr->current_trace->use_max_tr) {
5330 ret = -EBUSY;
5331 goto out;
5332 }
5333#endif
5334
5335 if (splice_grow_spd(pipe, &spd)) {
5336 ret = -ENOMEM;
5337 goto out;
5338 }
5339
5340 if (*ppos & (PAGE_SIZE - 1)) {
5341 ret = -EINVAL;
5342 goto out;
5343 }
5344
5345 if (len & (PAGE_SIZE - 1)) {
5346 if (len < PAGE_SIZE) {
5347 ret = -EINVAL;
5348 goto out;
5349 }
5350 len &= PAGE_MASK;
5351 }
5352
5353 again:
5354 trace_access_lock(iter->cpu_file);
5355 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
5356
5357 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
5358 struct page *page;
5359 int r;
5360
5361 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
5362 if (!ref)
5363 break;
5364
5365 ref->ref = 1;
5366 ref->buffer = iter->trace_buffer->buffer;
5367 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
5368 if (!ref->page) {
5369 kfree(ref);
5370 break;
5371 }
5372
5373 r = ring_buffer_read_page(ref->buffer, &ref->page,
5374 len, iter->cpu_file, 1);
5375 if (r < 0) {
5376 ring_buffer_free_read_page(ref->buffer, ref->page);
5377 kfree(ref);
5378 break;
5379 }
5380
5381 /*
5382 * zero out any left over data, this is going to
5383 * user land.
5384 */
5385 size = ring_buffer_page_len(ref->page);
5386 if (size < PAGE_SIZE)
5387 memset(ref->page + size, 0, PAGE_SIZE - size);
5388
5389 page = virt_to_page(ref->page);
5390
5391 spd.pages[i] = page;
5392 spd.partial[i].len = PAGE_SIZE;
5393 spd.partial[i].offset = 0;
5394 spd.partial[i].private = (unsigned long)ref;
5395 spd.nr_pages++;
5396 *ppos += PAGE_SIZE;
5397
5398 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
5399 }
5400
5401 trace_access_unlock(iter->cpu_file);
5402 spd.nr_pages = i;
5403
5404 /* did we read anything? */
5405 if (!spd.nr_pages) {
5406 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) {
5407 ret = -EAGAIN;
5408 goto out;
5409 }
5410 mutex_unlock(&trace_types_lock);
5411 iter->trace->wait_pipe(iter);
5412 mutex_lock(&trace_types_lock);
5413 if (signal_pending(current)) {
5414 ret = -EINTR;
5415 goto out;
5416 }
5417 goto again;
5418 }
5419
5420 ret = splice_to_pipe(pipe, &spd);
5421 splice_shrink_spd(&spd);
5422out:
5423 mutex_unlock(&trace_types_lock);
5424
5425 return ret;
5426}
5427
5428static const struct file_operations tracing_buffers_fops = {
5429 .open = tracing_buffers_open,
5430 .read = tracing_buffers_read,
5431 .poll = tracing_buffers_poll,
5432 .release = tracing_buffers_release,
5433 .splice_read = tracing_buffers_splice_read,
5434 .llseek = no_llseek,
5435};
5436
5437static ssize_t
5438tracing_stats_read(struct file *filp, char __user *ubuf,
5439 size_t count, loff_t *ppos)
5440{
5441 struct inode *inode = file_inode(filp);
5442 struct trace_array *tr = inode->i_private;
5443 struct trace_buffer *trace_buf = &tr->trace_buffer;
5444 int cpu = tracing_get_cpu(inode);
5445 struct trace_seq *s;
5446 unsigned long cnt;
5447 unsigned long long t;
5448 unsigned long usec_rem;
5449
5450 s = kmalloc(sizeof(*s), GFP_KERNEL);
5451 if (!s)
5452 return -ENOMEM;
5453
5454 trace_seq_init(s);
5455
5456 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
5457 trace_seq_printf(s, "entries: %ld\n", cnt);
5458
5459 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
5460 trace_seq_printf(s, "overrun: %ld\n", cnt);
5461
5462 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
5463 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
5464
5465 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
5466 trace_seq_printf(s, "bytes: %ld\n", cnt);
5467
5468 if (trace_clocks[tr->clock_id].in_ns) {
5469 /* local or global for trace_clock */
5470 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
5471 usec_rem = do_div(t, USEC_PER_SEC);
5472 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
5473 t, usec_rem);
5474
5475 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu));
5476 usec_rem = do_div(t, USEC_PER_SEC);
5477 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
5478 } else {
5479 /* counter or tsc mode for trace_clock */
5480 trace_seq_printf(s, "oldest event ts: %llu\n",
5481 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
5482
5483 trace_seq_printf(s, "now ts: %llu\n",
5484 ring_buffer_time_stamp(trace_buf->buffer, cpu));
5485 }
5486
5487 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
5488 trace_seq_printf(s, "dropped events: %ld\n", cnt);
5489
5490 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
5491 trace_seq_printf(s, "read events: %ld\n", cnt);
5492
5493 count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
5494
5495 kfree(s);
5496
5497 return count;
5498}
5499
5500static const struct file_operations tracing_stats_fops = {
5501 .open = tracing_open_generic_tr,
5502 .read = tracing_stats_read,
5503 .llseek = generic_file_llseek,
5504 .release = tracing_release_generic_tr,
5505};
5506
5507#ifdef CONFIG_DYNAMIC_FTRACE
5508
5509int __weak ftrace_arch_read_dyn_info(char *buf, int size)
5510{
5511 return 0;
5512}
5513
5514static ssize_t
5515tracing_read_dyn_info(struct file *filp, char __user *ubuf,
5516 size_t cnt, loff_t *ppos)
5517{
5518 static char ftrace_dyn_info_buffer[1024];
5519 static DEFINE_MUTEX(dyn_info_mutex);
5520 unsigned long *p = filp->private_data;
5521 char *buf = ftrace_dyn_info_buffer;
5522 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
5523 int r;
5524
5525 mutex_lock(&dyn_info_mutex);
5526 r = sprintf(buf, "%ld ", *p);
5527
5528 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
5529 buf[r++] = '\n';
5530
5531 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5532
5533 mutex_unlock(&dyn_info_mutex);
5534
5535 return r;
5536}
5537
5538static const struct file_operations tracing_dyn_info_fops = {
5539 .open = tracing_open_generic,
5540 .read = tracing_read_dyn_info,
5541 .llseek = generic_file_llseek,
5542};
5543#endif /* CONFIG_DYNAMIC_FTRACE */
5544
5545#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5546static void
5547ftrace_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
5548{
5549 tracing_snapshot();
5550}
5551
5552static void
5553ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
5554{
5555 unsigned long *count = (long *)data;
5556
5557 if (!*count)
5558 return;
5559
5560 if (*count != -1)
5561 (*count)--;
5562
5563 tracing_snapshot();
5564}
5565
5566static int
5567ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
5568 struct ftrace_probe_ops *ops, void *data)
5569{
5570 long count = (long)data;
5571
5572 seq_printf(m, "%ps:", (void *)ip);
5573
5574 seq_printf(m, "snapshot");
5575
5576 if (count == -1)
5577 seq_printf(m, ":unlimited\n");
5578 else
5579 seq_printf(m, ":count=%ld\n", count);
5580
5581 return 0;
5582}
5583
5584static struct ftrace_probe_ops snapshot_probe_ops = {
5585 .func = ftrace_snapshot,
5586 .print = ftrace_snapshot_print,
5587};
5588
5589static struct ftrace_probe_ops snapshot_count_probe_ops = {
5590 .func = ftrace_count_snapshot,
5591 .print = ftrace_snapshot_print,
5592};
5593
5594static int
5595ftrace_trace_snapshot_callback(struct ftrace_hash *hash,
5596 char *glob, char *cmd, char *param, int enable)
5597{
5598 struct ftrace_probe_ops *ops;
5599 void *count = (void *)-1;
5600 char *number;
5601 int ret;
5602
5603 /* hash funcs only work with set_ftrace_filter */
5604 if (!enable)
5605 return -EINVAL;
5606
5607 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
5608
5609 if (glob[0] == '!') {
5610 unregister_ftrace_function_probe_func(glob+1, ops);
5611 return 0;
5612 }
5613
5614 if (!param)
5615 goto out_reg;
5616
5617 number = strsep(¶m, ":");
5618
5619 if (!strlen(number))
5620 goto out_reg;
5621
5622 /*
5623 * We use the callback data field (which is a pointer)
5624 * as our counter.
5625 */
5626 ret = kstrtoul(number, 0, (unsigned long *)&count);
5627 if (ret)
5628 return ret;
5629
5630 out_reg:
5631 ret = register_ftrace_function_probe(glob, ops, count);
5632
5633 if (ret >= 0)
5634 alloc_snapshot(&global_trace);
5635
5636 return ret < 0 ? ret : 0;
5637}
5638
5639static struct ftrace_func_command ftrace_snapshot_cmd = {
5640 .name = "snapshot",
5641 .func = ftrace_trace_snapshot_callback,
5642};
5643
5644static __init int register_snapshot_cmd(void)
5645{
5646 return register_ftrace_command(&ftrace_snapshot_cmd);
5647}
5648#else
5649static inline __init int register_snapshot_cmd(void) { return 0; }
5650#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
5651
5652struct dentry *tracing_init_dentry_tr(struct trace_array *tr)
5653{
5654 if (tr->dir)
5655 return tr->dir;
5656
5657 if (!debugfs_initialized())
5658 return NULL;
5659
5660 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
5661 tr->dir = debugfs_create_dir("tracing", NULL);
5662
5663 if (!tr->dir)
5664 pr_warn_once("Could not create debugfs directory 'tracing'\n");
5665
5666 return tr->dir;
5667}
5668
5669struct dentry *tracing_init_dentry(void)
5670{
5671 return tracing_init_dentry_tr(&global_trace);
5672}
5673
5674static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
5675{
5676 struct dentry *d_tracer;
5677
5678 if (tr->percpu_dir)
5679 return tr->percpu_dir;
5680
5681 d_tracer = tracing_init_dentry_tr(tr);
5682 if (!d_tracer)
5683 return NULL;
5684
5685 tr->percpu_dir = debugfs_create_dir("per_cpu", d_tracer);
5686
5687 WARN_ONCE(!tr->percpu_dir,
5688 "Could not create debugfs directory 'per_cpu/%d'\n", cpu);
5689
5690 return tr->percpu_dir;
5691}
5692
5693static struct dentry *
5694trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
5695 void *data, long cpu, const struct file_operations *fops)
5696{
5697 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
5698
5699 if (ret) /* See tracing_get_cpu() */
5700 ret->d_inode->i_cdev = (void *)(cpu + 1);
5701 return ret;
5702}
5703
5704static void
5705tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
5706{
5707 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
5708 struct dentry *d_cpu;
5709 char cpu_dir[30]; /* 30 characters should be more than enough */
5710
5711 if (!d_percpu)
5712 return;
5713
5714 snprintf(cpu_dir, 30, "cpu%ld", cpu);
5715 d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
5716 if (!d_cpu) {
5717 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
5718 return;
5719 }
5720
5721 /* per cpu trace_pipe */
5722 trace_create_cpu_file("trace_pipe", 0444, d_cpu,
5723 tr, cpu, &tracing_pipe_fops);
5724
5725 /* per cpu trace */
5726 trace_create_cpu_file("trace", 0644, d_cpu,
5727 tr, cpu, &tracing_fops);
5728
5729 trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
5730 tr, cpu, &tracing_buffers_fops);
5731
5732 trace_create_cpu_file("stats", 0444, d_cpu,
5733 tr, cpu, &tracing_stats_fops);
5734
5735 trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
5736 tr, cpu, &tracing_entries_fops);
5737
5738#ifdef CONFIG_TRACER_SNAPSHOT
5739 trace_create_cpu_file("snapshot", 0644, d_cpu,
5740 tr, cpu, &snapshot_fops);
5741
5742 trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
5743 tr, cpu, &snapshot_raw_fops);
5744#endif
5745}
5746
5747#ifdef CONFIG_FTRACE_SELFTEST
5748/* Let selftest have access to static functions in this file */
5749#include "trace_selftest.c"
5750#endif
5751
5752struct trace_option_dentry {
5753 struct tracer_opt *opt;
5754 struct tracer_flags *flags;
5755 struct trace_array *tr;
5756 struct dentry *entry;
5757};
5758
5759static ssize_t
5760trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
5761 loff_t *ppos)
5762{
5763 struct trace_option_dentry *topt = filp->private_data;
5764 char *buf;
5765
5766 if (topt->flags->val & topt->opt->bit)
5767 buf = "1\n";
5768 else
5769 buf = "0\n";
5770
5771 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
5772}
5773
5774static ssize_t
5775trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
5776 loff_t *ppos)
5777{
5778 struct trace_option_dentry *topt = filp->private_data;
5779 unsigned long val;
5780 int ret;
5781
5782 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5783 if (ret)
5784 return ret;
5785
5786 if (val != 0 && val != 1)
5787 return -EINVAL;
5788
5789 if (!!(topt->flags->val & topt->opt->bit) != val) {
5790 mutex_lock(&trace_types_lock);
5791 ret = __set_tracer_option(topt->tr, topt->flags,
5792 topt->opt, !val);
5793 mutex_unlock(&trace_types_lock);
5794 if (ret)
5795 return ret;
5796 }
5797
5798 *ppos += cnt;
5799
5800 return cnt;
5801}
5802
5803
5804static const struct file_operations trace_options_fops = {
5805 .open = tracing_open_generic,
5806 .read = trace_options_read,
5807 .write = trace_options_write,
5808 .llseek = generic_file_llseek,
5809};
5810
5811static ssize_t
5812trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
5813 loff_t *ppos)
5814{
5815 long index = (long)filp->private_data;
5816 char *buf;
5817
5818 if (trace_flags & (1 << index))
5819 buf = "1\n";
5820 else
5821 buf = "0\n";
5822
5823 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
5824}
5825
5826static ssize_t
5827trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
5828 loff_t *ppos)
5829{
5830 struct trace_array *tr = &global_trace;
5831 long index = (long)filp->private_data;
5832 unsigned long val;
5833 int ret;
5834
5835 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5836 if (ret)
5837 return ret;
5838
5839 if (val != 0 && val != 1)
5840 return -EINVAL;
5841
5842 mutex_lock(&trace_types_lock);
5843 ret = set_tracer_flag(tr, 1 << index, val);
5844 mutex_unlock(&trace_types_lock);
5845
5846 if (ret < 0)
5847 return ret;
5848
5849 *ppos += cnt;
5850
5851 return cnt;
5852}
5853
5854static const struct file_operations trace_options_core_fops = {
5855 .open = tracing_open_generic,
5856 .read = trace_options_core_read,
5857 .write = trace_options_core_write,
5858 .llseek = generic_file_llseek,
5859};
5860
5861struct dentry *trace_create_file(const char *name,
5862 umode_t mode,
5863 struct dentry *parent,
5864 void *data,
5865 const struct file_operations *fops)
5866{
5867 struct dentry *ret;
5868
5869 ret = debugfs_create_file(name, mode, parent, data, fops);
5870 if (!ret)
5871 pr_warning("Could not create debugfs '%s' entry\n", name);
5872
5873 return ret;
5874}
5875
5876
5877static struct dentry *trace_options_init_dentry(struct trace_array *tr)
5878{
5879 struct dentry *d_tracer;
5880
5881 if (tr->options)
5882 return tr->options;
5883
5884 d_tracer = tracing_init_dentry_tr(tr);
5885 if (!d_tracer)
5886 return NULL;
5887
5888 tr->options = debugfs_create_dir("options", d_tracer);
5889 if (!tr->options) {
5890 pr_warning("Could not create debugfs directory 'options'\n");
5891 return NULL;
5892 }
5893
5894 return tr->options;
5895}
5896
5897static void
5898create_trace_option_file(struct trace_array *tr,
5899 struct trace_option_dentry *topt,
5900 struct tracer_flags *flags,
5901 struct tracer_opt *opt)
5902{
5903 struct dentry *t_options;
5904
5905 t_options = trace_options_init_dentry(tr);
5906 if (!t_options)
5907 return;
5908
5909 topt->flags = flags;
5910 topt->opt = opt;
5911 topt->tr = tr;
5912
5913 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
5914 &trace_options_fops);
5915
5916}
5917
5918static struct trace_option_dentry *
5919create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
5920{
5921 struct trace_option_dentry *topts;
5922 struct tracer_flags *flags;
5923 struct tracer_opt *opts;
5924 int cnt;
5925
5926 if (!tracer)
5927 return NULL;
5928
5929 flags = tracer->flags;
5930
5931 if (!flags || !flags->opts)
5932 return NULL;
5933
5934 opts = flags->opts;
5935
5936 for (cnt = 0; opts[cnt].name; cnt++)
5937 ;
5938
5939 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
5940 if (!topts)
5941 return NULL;
5942
5943 for (cnt = 0; opts[cnt].name; cnt++)
5944 create_trace_option_file(tr, &topts[cnt], flags,
5945 &opts[cnt]);
5946
5947 return topts;
5948}
5949
5950static void
5951destroy_trace_option_files(struct trace_option_dentry *topts)
5952{
5953 int cnt;
5954
5955 if (!topts)
5956 return;
5957
5958 for (cnt = 0; topts[cnt].opt; cnt++) {
5959 if (topts[cnt].entry)
5960 debugfs_remove(topts[cnt].entry);
5961 }
5962
5963 kfree(topts);
5964}
5965
5966static struct dentry *
5967create_trace_option_core_file(struct trace_array *tr,
5968 const char *option, long index)
5969{
5970 struct dentry *t_options;
5971
5972 t_options = trace_options_init_dentry(tr);
5973 if (!t_options)
5974 return NULL;
5975
5976 return trace_create_file(option, 0644, t_options, (void *)index,
5977 &trace_options_core_fops);
5978}
5979
5980static __init void create_trace_options_dir(struct trace_array *tr)
5981{
5982 struct dentry *t_options;
5983 int i;
5984
5985 t_options = trace_options_init_dentry(tr);
5986 if (!t_options)
5987 return;
5988
5989 for (i = 0; trace_options[i]; i++)
5990 create_trace_option_core_file(tr, trace_options[i], i);
5991}
5992
5993static ssize_t
5994rb_simple_read(struct file *filp, char __user *ubuf,
5995 size_t cnt, loff_t *ppos)
5996{
5997 struct trace_array *tr = filp->private_data;
5998 char buf[64];
5999 int r;
6000
6001 r = tracer_tracing_is_on(tr);
6002 r = sprintf(buf, "%d\n", r);
6003
6004 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6005}
6006
6007static ssize_t
6008rb_simple_write(struct file *filp, const char __user *ubuf,
6009 size_t cnt, loff_t *ppos)
6010{
6011 struct trace_array *tr = filp->private_data;
6012 struct ring_buffer *buffer = tr->trace_buffer.buffer;
6013 unsigned long val;
6014 int ret;
6015
6016 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6017 if (ret)
6018 return ret;
6019
6020 if (buffer) {
6021 mutex_lock(&trace_types_lock);
6022 if (val) {
6023 tracer_tracing_on(tr);
6024 if (tr->current_trace->start)
6025 tr->current_trace->start(tr);
6026 } else {
6027 tracer_tracing_off(tr);
6028 if (tr->current_trace->stop)
6029 tr->current_trace->stop(tr);
6030 }
6031 mutex_unlock(&trace_types_lock);
6032 }
6033
6034 (*ppos)++;
6035
6036 return cnt;
6037}
6038
6039static const struct file_operations rb_simple_fops = {
6040 .open = tracing_open_generic_tr,
6041 .read = rb_simple_read,
6042 .write = rb_simple_write,
6043 .release = tracing_release_generic_tr,
6044 .llseek = default_llseek,
6045};
6046
6047struct dentry *trace_instance_dir;
6048
6049static void
6050init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer);
6051
6052static int
6053allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
6054{
6055 enum ring_buffer_flags rb_flags;
6056
6057 rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
6058
6059 buf->tr = tr;
6060
6061 buf->buffer = ring_buffer_alloc(size, rb_flags);
6062 if (!buf->buffer)
6063 return -ENOMEM;
6064
6065 buf->data = alloc_percpu(struct trace_array_cpu);
6066 if (!buf->data) {
6067 ring_buffer_free(buf->buffer);
6068 return -ENOMEM;
6069 }
6070
6071 /* Allocate the first page for all buffers */
6072 set_buffer_entries(&tr->trace_buffer,
6073 ring_buffer_size(tr->trace_buffer.buffer, 0));
6074
6075 return 0;
6076}
6077
6078static int allocate_trace_buffers(struct trace_array *tr, int size)
6079{
6080 int ret;
6081
6082 ret = allocate_trace_buffer(tr, &tr->trace_buffer, size);
6083 if (ret)
6084 return ret;
6085
6086#ifdef CONFIG_TRACER_MAX_TRACE
6087 ret = allocate_trace_buffer(tr, &tr->max_buffer,
6088 allocate_snapshot ? size : 1);
6089 if (WARN_ON(ret)) {
6090 ring_buffer_free(tr->trace_buffer.buffer);
6091 free_percpu(tr->trace_buffer.data);
6092 return -ENOMEM;
6093 }
6094 tr->allocated_snapshot = allocate_snapshot;
6095
6096 /*
6097 * Only the top level trace array gets its snapshot allocated
6098 * from the kernel command line.
6099 */
6100 allocate_snapshot = false;
6101#endif
6102 return 0;
6103}
6104
6105static int new_instance_create(const char *name)
6106{
6107 struct trace_array *tr;
6108 int ret;
6109
6110 mutex_lock(&trace_types_lock);
6111
6112 ret = -EEXIST;
6113 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6114 if (tr->name && strcmp(tr->name, name) == 0)
6115 goto out_unlock;
6116 }
6117
6118 ret = -ENOMEM;
6119 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
6120 if (!tr)
6121 goto out_unlock;
6122
6123 tr->name = kstrdup(name, GFP_KERNEL);
6124 if (!tr->name)
6125 goto out_free_tr;
6126
6127 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
6128 goto out_free_tr;
6129
6130 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
6131
6132 raw_spin_lock_init(&tr->start_lock);
6133
6134 tr->current_trace = &nop_trace;
6135
6136 INIT_LIST_HEAD(&tr->systems);
6137 INIT_LIST_HEAD(&tr->events);
6138
6139 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
6140 goto out_free_tr;
6141
6142 tr->dir = debugfs_create_dir(name, trace_instance_dir);
6143 if (!tr->dir)
6144 goto out_free_tr;
6145
6146 ret = event_trace_add_tracer(tr->dir, tr);
6147 if (ret) {
6148 debugfs_remove_recursive(tr->dir);
6149 goto out_free_tr;
6150 }
6151
6152 init_tracer_debugfs(tr, tr->dir);
6153
6154 list_add(&tr->list, &ftrace_trace_arrays);
6155
6156 mutex_unlock(&trace_types_lock);
6157
6158 return 0;
6159
6160 out_free_tr:
6161 if (tr->trace_buffer.buffer)
6162 ring_buffer_free(tr->trace_buffer.buffer);
6163 free_cpumask_var(tr->tracing_cpumask);
6164 kfree(tr->name);
6165 kfree(tr);
6166
6167 out_unlock:
6168 mutex_unlock(&trace_types_lock);
6169
6170 return ret;
6171
6172}
6173
6174static int instance_delete(const char *name)
6175{
6176 struct trace_array *tr;
6177 int found = 0;
6178 int ret;
6179
6180 mutex_lock(&trace_types_lock);
6181
6182 ret = -ENODEV;
6183 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6184 if (tr->name && strcmp(tr->name, name) == 0) {
6185 found = 1;
6186 break;
6187 }
6188 }
6189 if (!found)
6190 goto out_unlock;
6191
6192 ret = -EBUSY;
6193 if (tr->ref)
6194 goto out_unlock;
6195
6196 list_del(&tr->list);
6197
6198 tracing_set_nop(tr);
6199 event_trace_del_tracer(tr);
6200 ftrace_destroy_function_files(tr);
6201 debugfs_remove_recursive(tr->dir);
6202 free_percpu(tr->trace_buffer.data);
6203 ring_buffer_free(tr->trace_buffer.buffer);
6204
6205 kfree(tr->name);
6206 kfree(tr);
6207
6208 ret = 0;
6209
6210 out_unlock:
6211 mutex_unlock(&trace_types_lock);
6212
6213 return ret;
6214}
6215
6216static int instance_mkdir (struct inode *inode, struct dentry *dentry, umode_t mode)
6217{
6218 struct dentry *parent;
6219 int ret;
6220
6221 /* Paranoid: Make sure the parent is the "instances" directory */
6222 parent = hlist_entry(inode->i_dentry.first, struct dentry, d_alias);
6223 if (WARN_ON_ONCE(parent != trace_instance_dir))
6224 return -ENOENT;
6225
6226 /*
6227 * The inode mutex is locked, but debugfs_create_dir() will also
6228 * take the mutex. As the instances directory can not be destroyed
6229 * or changed in any other way, it is safe to unlock it, and
6230 * let the dentry try. If two users try to make the same dir at
6231 * the same time, then the new_instance_create() will determine the
6232 * winner.
6233 */
6234 mutex_unlock(&inode->i_mutex);
6235
6236 ret = new_instance_create(dentry->d_iname);
6237
6238 mutex_lock(&inode->i_mutex);
6239
6240 return ret;
6241}
6242
6243static int instance_rmdir(struct inode *inode, struct dentry *dentry)
6244{
6245 struct dentry *parent;
6246 int ret;
6247
6248 /* Paranoid: Make sure the parent is the "instances" directory */
6249 parent = hlist_entry(inode->i_dentry.first, struct dentry, d_alias);
6250 if (WARN_ON_ONCE(parent != trace_instance_dir))
6251 return -ENOENT;
6252
6253 /* The caller did a dget() on dentry */
6254 mutex_unlock(&dentry->d_inode->i_mutex);
6255
6256 /*
6257 * The inode mutex is locked, but debugfs_create_dir() will also
6258 * take the mutex. As the instances directory can not be destroyed
6259 * or changed in any other way, it is safe to unlock it, and
6260 * let the dentry try. If two users try to make the same dir at
6261 * the same time, then the instance_delete() will determine the
6262 * winner.
6263 */
6264 mutex_unlock(&inode->i_mutex);
6265
6266 ret = instance_delete(dentry->d_iname);
6267
6268 mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
6269 mutex_lock(&dentry->d_inode->i_mutex);
6270
6271 return ret;
6272}
6273
6274static const struct inode_operations instance_dir_inode_operations = {
6275 .lookup = simple_lookup,
6276 .mkdir = instance_mkdir,
6277 .rmdir = instance_rmdir,
6278};
6279
6280static __init void create_trace_instances(struct dentry *d_tracer)
6281{
6282 trace_instance_dir = debugfs_create_dir("instances", d_tracer);
6283 if (WARN_ON(!trace_instance_dir))
6284 return;
6285
6286 /* Hijack the dir inode operations, to allow mkdir */
6287 trace_instance_dir->d_inode->i_op = &instance_dir_inode_operations;
6288}
6289
6290static void
6291init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
6292{
6293 int cpu;
6294
6295 trace_create_file("available_tracers", 0444, d_tracer,
6296 tr, &show_traces_fops);
6297
6298 trace_create_file("current_tracer", 0644, d_tracer,
6299 tr, &set_tracer_fops);
6300
6301 trace_create_file("tracing_cpumask", 0644, d_tracer,
6302 tr, &tracing_cpumask_fops);
6303
6304 trace_create_file("trace_options", 0644, d_tracer,
6305 tr, &tracing_iter_fops);
6306
6307 trace_create_file("trace", 0644, d_tracer,
6308 tr, &tracing_fops);
6309
6310 trace_create_file("trace_pipe", 0444, d_tracer,
6311 tr, &tracing_pipe_fops);
6312
6313 trace_create_file("buffer_size_kb", 0644, d_tracer,
6314 tr, &tracing_entries_fops);
6315
6316 trace_create_file("buffer_total_size_kb", 0444, d_tracer,
6317 tr, &tracing_total_entries_fops);
6318
6319 trace_create_file("free_buffer", 0200, d_tracer,
6320 tr, &tracing_free_buffer_fops);
6321
6322 trace_create_file("trace_marker", 0220, d_tracer,
6323 tr, &tracing_mark_fops);
6324
6325 trace_create_file("trace_clock", 0644, d_tracer, tr,
6326 &trace_clock_fops);
6327
6328 trace_create_file("tracing_on", 0644, d_tracer,
6329 tr, &rb_simple_fops);
6330
6331 if (ftrace_create_function_files(tr, d_tracer))
6332 WARN(1, "Could not allocate function filter files");
6333
6334#ifdef CONFIG_TRACER_SNAPSHOT
6335 trace_create_file("snapshot", 0644, d_tracer,
6336 tr, &snapshot_fops);
6337#endif
6338
6339 for_each_tracing_cpu(cpu)
6340 tracing_init_debugfs_percpu(tr, cpu);
6341
6342}
6343
6344static __init int tracer_init_debugfs(void)
6345{
6346 struct dentry *d_tracer;
6347
6348 trace_access_lock_init();
6349
6350 d_tracer = tracing_init_dentry();
6351 if (!d_tracer)
6352 return 0;
6353
6354 init_tracer_debugfs(&global_trace, d_tracer);
6355
6356#ifdef CONFIG_TRACER_MAX_TRACE
6357 trace_create_file("tracing_max_latency", 0644, d_tracer,
6358 &tracing_max_latency, &tracing_max_lat_fops);
6359#endif
6360
6361 trace_create_file("tracing_thresh", 0644, d_tracer,
6362 &tracing_thresh, &tracing_max_lat_fops);
6363
6364 trace_create_file("README", 0444, d_tracer,
6365 NULL, &tracing_readme_fops);
6366
6367 trace_create_file("saved_cmdlines", 0444, d_tracer,
6368 NULL, &tracing_saved_cmdlines_fops);
6369
6370#ifdef CONFIG_DYNAMIC_FTRACE
6371 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
6372 &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
6373#endif
6374
6375 create_trace_instances(d_tracer);
6376
6377 create_trace_options_dir(&global_trace);
6378
6379 return 0;
6380}
6381
6382static int trace_panic_handler(struct notifier_block *this,
6383 unsigned long event, void *unused)
6384{
6385 if (ftrace_dump_on_oops)
6386 ftrace_dump(ftrace_dump_on_oops);
6387 return NOTIFY_OK;
6388}
6389
6390static struct notifier_block trace_panic_notifier = {
6391 .notifier_call = trace_panic_handler,
6392 .next = NULL,
6393 .priority = 150 /* priority: INT_MAX >= x >= 0 */
6394};
6395
6396static int trace_die_handler(struct notifier_block *self,
6397 unsigned long val,
6398 void *data)
6399{
6400 switch (val) {
6401 case DIE_OOPS:
6402 if (ftrace_dump_on_oops)
6403 ftrace_dump(ftrace_dump_on_oops);
6404 break;
6405 default:
6406 break;
6407 }
6408 return NOTIFY_OK;
6409}
6410
6411static struct notifier_block trace_die_notifier = {
6412 .notifier_call = trace_die_handler,
6413 .priority = 200
6414};
6415
6416/*
6417 * printk is set to max of 1024, we really don't need it that big.
6418 * Nothing should be printing 1000 characters anyway.
6419 */
6420#define TRACE_MAX_PRINT 1000
6421
6422/*
6423 * Define here KERN_TRACE so that we have one place to modify
6424 * it if we decide to change what log level the ftrace dump
6425 * should be at.
6426 */
6427#define KERN_TRACE KERN_EMERG
6428
6429void
6430trace_printk_seq(struct trace_seq *s)
6431{
6432 /* Probably should print a warning here. */
6433 if (s->len >= TRACE_MAX_PRINT)
6434 s->len = TRACE_MAX_PRINT;
6435
6436 /* should be zero ended, but we are paranoid. */
6437 s->buffer[s->len] = 0;
6438
6439 printk(KERN_TRACE "%s", s->buffer);
6440
6441 trace_seq_init(s);
6442}
6443
6444void trace_init_global_iter(struct trace_iterator *iter)
6445{
6446 iter->tr = &global_trace;
6447 iter->trace = iter->tr->current_trace;
6448 iter->cpu_file = RING_BUFFER_ALL_CPUS;
6449 iter->trace_buffer = &global_trace.trace_buffer;
6450
6451 if (iter->trace && iter->trace->open)
6452 iter->trace->open(iter);
6453
6454 /* Annotate start of buffers if we had overruns */
6455 if (ring_buffer_overruns(iter->trace_buffer->buffer))
6456 iter->iter_flags |= TRACE_FILE_ANNOTATE;
6457
6458 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
6459 if (trace_clocks[iter->tr->clock_id].in_ns)
6460 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
6461}
6462
6463void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
6464{
6465 /* use static because iter can be a bit big for the stack */
6466 static struct trace_iterator iter;
6467 static atomic_t dump_running;
6468 unsigned int old_userobj;
6469 unsigned long flags;
6470 int cnt = 0, cpu;
6471
6472 /* Only allow one dump user at a time. */
6473 if (atomic_inc_return(&dump_running) != 1) {
6474 atomic_dec(&dump_running);
6475 return;
6476 }
6477
6478 /*
6479 * Always turn off tracing when we dump.
6480 * We don't need to show trace output of what happens
6481 * between multiple crashes.
6482 *
6483 * If the user does a sysrq-z, then they can re-enable
6484 * tracing with echo 1 > tracing_on.
6485 */
6486 tracing_off();
6487
6488 local_irq_save(flags);
6489
6490 /* Simulate the iterator */
6491 trace_init_global_iter(&iter);
6492
6493 for_each_tracing_cpu(cpu) {
6494 atomic_inc(&per_cpu_ptr(iter.tr->trace_buffer.data, cpu)->disabled);
6495 }
6496
6497 old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
6498
6499 /* don't look at user memory in panic mode */
6500 trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
6501
6502 switch (oops_dump_mode) {
6503 case DUMP_ALL:
6504 iter.cpu_file = RING_BUFFER_ALL_CPUS;
6505 break;
6506 case DUMP_ORIG:
6507 iter.cpu_file = raw_smp_processor_id();
6508 break;
6509 case DUMP_NONE:
6510 goto out_enable;
6511 default:
6512 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
6513 iter.cpu_file = RING_BUFFER_ALL_CPUS;
6514 }
6515
6516 printk(KERN_TRACE "Dumping ftrace buffer:\n");
6517
6518 /* Did function tracer already get disabled? */
6519 if (ftrace_is_dead()) {
6520 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
6521 printk("# MAY BE MISSING FUNCTION EVENTS\n");
6522 }
6523
6524 /*
6525 * We need to stop all tracing on all CPUS to read the
6526 * the next buffer. This is a bit expensive, but is
6527 * not done often. We fill all what we can read,
6528 * and then release the locks again.
6529 */
6530
6531 while (!trace_empty(&iter)) {
6532
6533 if (!cnt)
6534 printk(KERN_TRACE "---------------------------------\n");
6535
6536 cnt++;
6537
6538 /* reset all but tr, trace, and overruns */
6539 memset(&iter.seq, 0,
6540 sizeof(struct trace_iterator) -
6541 offsetof(struct trace_iterator, seq));
6542 iter.iter_flags |= TRACE_FILE_LAT_FMT;
6543 iter.pos = -1;
6544
6545 if (trace_find_next_entry_inc(&iter) != NULL) {
6546 int ret;
6547
6548 ret = print_trace_line(&iter);
6549 if (ret != TRACE_TYPE_NO_CONSUME)
6550 trace_consume(&iter);
6551 }
6552 touch_nmi_watchdog();
6553
6554 trace_printk_seq(&iter.seq);
6555 }
6556
6557 if (!cnt)
6558 printk(KERN_TRACE " (ftrace buffer empty)\n");
6559 else
6560 printk(KERN_TRACE "---------------------------------\n");
6561
6562 out_enable:
6563 trace_flags |= old_userobj;
6564
6565 for_each_tracing_cpu(cpu) {
6566 atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
6567 }
6568 atomic_dec(&dump_running);
6569 local_irq_restore(flags);
6570}
6571EXPORT_SYMBOL_GPL(ftrace_dump);
6572
6573__init static int tracer_alloc_buffers(void)
6574{
6575 int ring_buf_size;
6576 int ret = -ENOMEM;
6577
6578
6579 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
6580 goto out;
6581
6582 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
6583 goto out_free_buffer_mask;
6584
6585 /* Only allocate trace_printk buffers if a trace_printk exists */
6586 if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
6587 /* Must be called before global_trace.buffer is allocated */
6588 trace_printk_init_buffers();
6589
6590 /* To save memory, keep the ring buffer size to its minimum */
6591 if (ring_buffer_expanded)
6592 ring_buf_size = trace_buf_size;
6593 else
6594 ring_buf_size = 1;
6595
6596 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
6597 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
6598
6599 raw_spin_lock_init(&global_trace.start_lock);
6600
6601 /* Used for event triggers */
6602 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
6603 if (!temp_buffer)
6604 goto out_free_cpumask;
6605
6606 /* TODO: make the number of buffers hot pluggable with CPUS */
6607 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
6608 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
6609 WARN_ON(1);
6610 goto out_free_temp_buffer;
6611 }
6612
6613 if (global_trace.buffer_disabled)
6614 tracing_off();
6615
6616 trace_init_cmdlines();
6617
6618 if (trace_boot_clock) {
6619 ret = tracing_set_clock(&global_trace, trace_boot_clock);
6620 if (ret < 0)
6621 pr_warning("Trace clock %s not defined, going back to default\n",
6622 trace_boot_clock);
6623 }
6624
6625 /*
6626 * register_tracer() might reference current_trace, so it
6627 * needs to be set before we register anything. This is
6628 * just a bootstrap of current_trace anyway.
6629 */
6630 global_trace.current_trace = &nop_trace;
6631
6632 register_tracer(&nop_trace);
6633
6634 /* All seems OK, enable tracing */
6635 tracing_disabled = 0;
6636
6637 atomic_notifier_chain_register(&panic_notifier_list,
6638 &trace_panic_notifier);
6639
6640 register_die_notifier(&trace_die_notifier);
6641
6642 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
6643
6644 INIT_LIST_HEAD(&global_trace.systems);
6645 INIT_LIST_HEAD(&global_trace.events);
6646 list_add(&global_trace.list, &ftrace_trace_arrays);
6647
6648 while (trace_boot_options) {
6649 char *option;
6650
6651 option = strsep(&trace_boot_options, ",");
6652 trace_set_options(&global_trace, option);
6653 }
6654
6655 register_snapshot_cmd();
6656
6657 return 0;
6658
6659out_free_temp_buffer:
6660 ring_buffer_free(temp_buffer);
6661out_free_cpumask:
6662 free_percpu(global_trace.trace_buffer.data);
6663#ifdef CONFIG_TRACER_MAX_TRACE
6664 free_percpu(global_trace.max_buffer.data);
6665#endif
6666 free_cpumask_var(global_trace.tracing_cpumask);
6667out_free_buffer_mask:
6668 free_cpumask_var(tracing_buffer_mask);
6669out:
6670 return ret;
6671}
6672
6673__init static int clear_boot_tracer(void)
6674{
6675 /*
6676 * The default tracer at boot buffer is an init section.
6677 * This function is called in lateinit. If we did not
6678 * find the boot tracer, then clear it out, to prevent
6679 * later registration from accessing the buffer that is
6680 * about to be freed.
6681 */
6682 if (!default_bootup_tracer)
6683 return 0;
6684
6685 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
6686 default_bootup_tracer);
6687 default_bootup_tracer = NULL;
6688
6689 return 0;
6690}
6691
6692early_initcall(tracer_alloc_buffers);
6693fs_initcall(tracer_init_debugfs);
6694late_initcall(clear_boot_tracer);