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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ring buffer based function tracer
4 *
5 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Originally taken from the RT patch by:
9 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 *
11 * Based on code from the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 Nadia Yvette Chambers
14 */
15#include <linux/ring_buffer.h>
16#include <generated/utsrelease.h>
17#include <linux/stacktrace.h>
18#include <linux/writeback.h>
19#include <linux/kallsyms.h>
20#include <linux/security.h>
21#include <linux/seq_file.h>
22#include <linux/notifier.h>
23#include <linux/irqflags.h>
24#include <linux/debugfs.h>
25#include <linux/tracefs.h>
26#include <linux/pagemap.h>
27#include <linux/hardirq.h>
28#include <linux/linkage.h>
29#include <linux/uaccess.h>
30#include <linux/vmalloc.h>
31#include <linux/ftrace.h>
32#include <linux/module.h>
33#include <linux/percpu.h>
34#include <linux/splice.h>
35#include <linux/kdebug.h>
36#include <linux/string.h>
37#include <linux/mount.h>
38#include <linux/rwsem.h>
39#include <linux/slab.h>
40#include <linux/ctype.h>
41#include <linux/init.h>
42#include <linux/panic_notifier.h>
43#include <linux/poll.h>
44#include <linux/nmi.h>
45#include <linux/fs.h>
46#include <linux/trace.h>
47#include <linux/sched/clock.h>
48#include <linux/sched/rt.h>
49#include <linux/fsnotify.h>
50#include <linux/irq_work.h>
51#include <linux/workqueue.h>
52
53#include "trace.h"
54#include "trace_output.h"
55
56/*
57 * On boot up, the ring buffer is set to the minimum size, so that
58 * we do not waste memory on systems that are not using tracing.
59 */
60bool ring_buffer_expanded;
61
62/*
63 * We need to change this state when a selftest is running.
64 * A selftest will lurk into the ring-buffer to count the
65 * entries inserted during the selftest although some concurrent
66 * insertions into the ring-buffer such as trace_printk could occurred
67 * at the same time, giving false positive or negative results.
68 */
69static bool __read_mostly tracing_selftest_running;
70
71/*
72 * If boot-time tracing including tracers/events via kernel cmdline
73 * is running, we do not want to run SELFTEST.
74 */
75bool __read_mostly tracing_selftest_disabled;
76
77#ifdef CONFIG_FTRACE_STARTUP_TEST
78void __init disable_tracing_selftest(const char *reason)
79{
80 if (!tracing_selftest_disabled) {
81 tracing_selftest_disabled = true;
82 pr_info("Ftrace startup test is disabled due to %s\n", reason);
83 }
84}
85#endif
86
87/* Pipe tracepoints to printk */
88struct trace_iterator *tracepoint_print_iter;
89int tracepoint_printk;
90static bool tracepoint_printk_stop_on_boot __initdata;
91static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
92
93/* For tracers that don't implement custom flags */
94static struct tracer_opt dummy_tracer_opt[] = {
95 { }
96};
97
98static int
99dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
100{
101 return 0;
102}
103
104/*
105 * To prevent the comm cache from being overwritten when no
106 * tracing is active, only save the comm when a trace event
107 * occurred.
108 */
109static DEFINE_PER_CPU(bool, trace_taskinfo_save);
110
111/*
112 * Kill all tracing for good (never come back).
113 * It is initialized to 1 but will turn to zero if the initialization
114 * of the tracer is successful. But that is the only place that sets
115 * this back to zero.
116 */
117static int tracing_disabled = 1;
118
119cpumask_var_t __read_mostly tracing_buffer_mask;
120
121/*
122 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
123 *
124 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
125 * is set, then ftrace_dump is called. This will output the contents
126 * of the ftrace buffers to the console. This is very useful for
127 * capturing traces that lead to crashes and outputing it to a
128 * serial console.
129 *
130 * It is default off, but you can enable it with either specifying
131 * "ftrace_dump_on_oops" in the kernel command line, or setting
132 * /proc/sys/kernel/ftrace_dump_on_oops
133 * Set 1 if you want to dump buffers of all CPUs
134 * Set 2 if you want to dump the buffer of the CPU that triggered oops
135 */
136
137enum ftrace_dump_mode ftrace_dump_on_oops;
138
139/* When set, tracing will stop when a WARN*() is hit */
140int __disable_trace_on_warning;
141
142#ifdef CONFIG_TRACE_EVAL_MAP_FILE
143/* Map of enums to their values, for "eval_map" file */
144struct trace_eval_map_head {
145 struct module *mod;
146 unsigned long length;
147};
148
149union trace_eval_map_item;
150
151struct trace_eval_map_tail {
152 /*
153 * "end" is first and points to NULL as it must be different
154 * than "mod" or "eval_string"
155 */
156 union trace_eval_map_item *next;
157 const char *end; /* points to NULL */
158};
159
160static DEFINE_MUTEX(trace_eval_mutex);
161
162/*
163 * The trace_eval_maps are saved in an array with two extra elements,
164 * one at the beginning, and one at the end. The beginning item contains
165 * the count of the saved maps (head.length), and the module they
166 * belong to if not built in (head.mod). The ending item contains a
167 * pointer to the next array of saved eval_map items.
168 */
169union trace_eval_map_item {
170 struct trace_eval_map map;
171 struct trace_eval_map_head head;
172 struct trace_eval_map_tail tail;
173};
174
175static union trace_eval_map_item *trace_eval_maps;
176#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
177
178int tracing_set_tracer(struct trace_array *tr, const char *buf);
179static void ftrace_trace_userstack(struct trace_array *tr,
180 struct trace_buffer *buffer,
181 unsigned int trace_ctx);
182
183#define MAX_TRACER_SIZE 100
184static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
185static char *default_bootup_tracer;
186
187static bool allocate_snapshot;
188
189static int __init set_cmdline_ftrace(char *str)
190{
191 strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
192 default_bootup_tracer = bootup_tracer_buf;
193 /* We are using ftrace early, expand it */
194 ring_buffer_expanded = true;
195 return 1;
196}
197__setup("ftrace=", set_cmdline_ftrace);
198
199static int __init set_ftrace_dump_on_oops(char *str)
200{
201 if (*str++ != '=' || !*str || !strcmp("1", str)) {
202 ftrace_dump_on_oops = DUMP_ALL;
203 return 1;
204 }
205
206 if (!strcmp("orig_cpu", str) || !strcmp("2", str)) {
207 ftrace_dump_on_oops = DUMP_ORIG;
208 return 1;
209 }
210
211 return 0;
212}
213__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
214
215static int __init stop_trace_on_warning(char *str)
216{
217 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
218 __disable_trace_on_warning = 1;
219 return 1;
220}
221__setup("traceoff_on_warning", stop_trace_on_warning);
222
223static int __init boot_alloc_snapshot(char *str)
224{
225 allocate_snapshot = true;
226 /* We also need the main ring buffer expanded */
227 ring_buffer_expanded = true;
228 return 1;
229}
230__setup("alloc_snapshot", boot_alloc_snapshot);
231
232
233static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
234
235static int __init set_trace_boot_options(char *str)
236{
237 strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
238 return 0;
239}
240__setup("trace_options=", set_trace_boot_options);
241
242static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
243static char *trace_boot_clock __initdata;
244
245static int __init set_trace_boot_clock(char *str)
246{
247 strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
248 trace_boot_clock = trace_boot_clock_buf;
249 return 0;
250}
251__setup("trace_clock=", set_trace_boot_clock);
252
253static int __init set_tracepoint_printk(char *str)
254{
255 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
256 tracepoint_printk = 1;
257 return 1;
258}
259__setup("tp_printk", set_tracepoint_printk);
260
261static int __init set_tracepoint_printk_stop(char *str)
262{
263 tracepoint_printk_stop_on_boot = true;
264 return 1;
265}
266__setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop);
267
268unsigned long long ns2usecs(u64 nsec)
269{
270 nsec += 500;
271 do_div(nsec, 1000);
272 return nsec;
273}
274
275static void
276trace_process_export(struct trace_export *export,
277 struct ring_buffer_event *event, int flag)
278{
279 struct trace_entry *entry;
280 unsigned int size = 0;
281
282 if (export->flags & flag) {
283 entry = ring_buffer_event_data(event);
284 size = ring_buffer_event_length(event);
285 export->write(export, entry, size);
286 }
287}
288
289static DEFINE_MUTEX(ftrace_export_lock);
290
291static struct trace_export __rcu *ftrace_exports_list __read_mostly;
292
293static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled);
294static DEFINE_STATIC_KEY_FALSE(trace_event_exports_enabled);
295static DEFINE_STATIC_KEY_FALSE(trace_marker_exports_enabled);
296
297static inline void ftrace_exports_enable(struct trace_export *export)
298{
299 if (export->flags & TRACE_EXPORT_FUNCTION)
300 static_branch_inc(&trace_function_exports_enabled);
301
302 if (export->flags & TRACE_EXPORT_EVENT)
303 static_branch_inc(&trace_event_exports_enabled);
304
305 if (export->flags & TRACE_EXPORT_MARKER)
306 static_branch_inc(&trace_marker_exports_enabled);
307}
308
309static inline void ftrace_exports_disable(struct trace_export *export)
310{
311 if (export->flags & TRACE_EXPORT_FUNCTION)
312 static_branch_dec(&trace_function_exports_enabled);
313
314 if (export->flags & TRACE_EXPORT_EVENT)
315 static_branch_dec(&trace_event_exports_enabled);
316
317 if (export->flags & TRACE_EXPORT_MARKER)
318 static_branch_dec(&trace_marker_exports_enabled);
319}
320
321static void ftrace_exports(struct ring_buffer_event *event, int flag)
322{
323 struct trace_export *export;
324
325 preempt_disable_notrace();
326
327 export = rcu_dereference_raw_check(ftrace_exports_list);
328 while (export) {
329 trace_process_export(export, event, flag);
330 export = rcu_dereference_raw_check(export->next);
331 }
332
333 preempt_enable_notrace();
334}
335
336static inline void
337add_trace_export(struct trace_export **list, struct trace_export *export)
338{
339 rcu_assign_pointer(export->next, *list);
340 /*
341 * We are entering export into the list but another
342 * CPU might be walking that list. We need to make sure
343 * the export->next pointer is valid before another CPU sees
344 * the export pointer included into the list.
345 */
346 rcu_assign_pointer(*list, export);
347}
348
349static inline int
350rm_trace_export(struct trace_export **list, struct trace_export *export)
351{
352 struct trace_export **p;
353
354 for (p = list; *p != NULL; p = &(*p)->next)
355 if (*p == export)
356 break;
357
358 if (*p != export)
359 return -1;
360
361 rcu_assign_pointer(*p, (*p)->next);
362
363 return 0;
364}
365
366static inline void
367add_ftrace_export(struct trace_export **list, struct trace_export *export)
368{
369 ftrace_exports_enable(export);
370
371 add_trace_export(list, export);
372}
373
374static inline int
375rm_ftrace_export(struct trace_export **list, struct trace_export *export)
376{
377 int ret;
378
379 ret = rm_trace_export(list, export);
380 ftrace_exports_disable(export);
381
382 return ret;
383}
384
385int register_ftrace_export(struct trace_export *export)
386{
387 if (WARN_ON_ONCE(!export->write))
388 return -1;
389
390 mutex_lock(&ftrace_export_lock);
391
392 add_ftrace_export(&ftrace_exports_list, export);
393
394 mutex_unlock(&ftrace_export_lock);
395
396 return 0;
397}
398EXPORT_SYMBOL_GPL(register_ftrace_export);
399
400int unregister_ftrace_export(struct trace_export *export)
401{
402 int ret;
403
404 mutex_lock(&ftrace_export_lock);
405
406 ret = rm_ftrace_export(&ftrace_exports_list, export);
407
408 mutex_unlock(&ftrace_export_lock);
409
410 return ret;
411}
412EXPORT_SYMBOL_GPL(unregister_ftrace_export);
413
414/* trace_flags holds trace_options default values */
415#define TRACE_DEFAULT_FLAGS \
416 (FUNCTION_DEFAULT_FLAGS | \
417 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
418 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
419 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
420 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | \
421 TRACE_ITER_HASH_PTR)
422
423/* trace_options that are only supported by global_trace */
424#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
425 TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
426
427/* trace_flags that are default zero for instances */
428#define ZEROED_TRACE_FLAGS \
429 (TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK)
430
431/*
432 * The global_trace is the descriptor that holds the top-level tracing
433 * buffers for the live tracing.
434 */
435static struct trace_array global_trace = {
436 .trace_flags = TRACE_DEFAULT_FLAGS,
437};
438
439LIST_HEAD(ftrace_trace_arrays);
440
441int trace_array_get(struct trace_array *this_tr)
442{
443 struct trace_array *tr;
444 int ret = -ENODEV;
445
446 mutex_lock(&trace_types_lock);
447 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
448 if (tr == this_tr) {
449 tr->ref++;
450 ret = 0;
451 break;
452 }
453 }
454 mutex_unlock(&trace_types_lock);
455
456 return ret;
457}
458
459static void __trace_array_put(struct trace_array *this_tr)
460{
461 WARN_ON(!this_tr->ref);
462 this_tr->ref--;
463}
464
465/**
466 * trace_array_put - Decrement the reference counter for this trace array.
467 * @this_tr : pointer to the trace array
468 *
469 * NOTE: Use this when we no longer need the trace array returned by
470 * trace_array_get_by_name(). This ensures the trace array can be later
471 * destroyed.
472 *
473 */
474void trace_array_put(struct trace_array *this_tr)
475{
476 if (!this_tr)
477 return;
478
479 mutex_lock(&trace_types_lock);
480 __trace_array_put(this_tr);
481 mutex_unlock(&trace_types_lock);
482}
483EXPORT_SYMBOL_GPL(trace_array_put);
484
485int tracing_check_open_get_tr(struct trace_array *tr)
486{
487 int ret;
488
489 ret = security_locked_down(LOCKDOWN_TRACEFS);
490 if (ret)
491 return ret;
492
493 if (tracing_disabled)
494 return -ENODEV;
495
496 if (tr && trace_array_get(tr) < 0)
497 return -ENODEV;
498
499 return 0;
500}
501
502int call_filter_check_discard(struct trace_event_call *call, void *rec,
503 struct trace_buffer *buffer,
504 struct ring_buffer_event *event)
505{
506 if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
507 !filter_match_preds(call->filter, rec)) {
508 __trace_event_discard_commit(buffer, event);
509 return 1;
510 }
511
512 return 0;
513}
514
515void trace_free_pid_list(struct trace_pid_list *pid_list)
516{
517 vfree(pid_list->pids);
518 kfree(pid_list);
519}
520
521/**
522 * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
523 * @filtered_pids: The list of pids to check
524 * @search_pid: The PID to find in @filtered_pids
525 *
526 * Returns true if @search_pid is found in @filtered_pids, and false otherwise.
527 */
528bool
529trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
530{
531 /*
532 * If pid_max changed after filtered_pids was created, we
533 * by default ignore all pids greater than the previous pid_max.
534 */
535 if (search_pid >= filtered_pids->pid_max)
536 return false;
537
538 return test_bit(search_pid, filtered_pids->pids);
539}
540
541/**
542 * trace_ignore_this_task - should a task be ignored for tracing
543 * @filtered_pids: The list of pids to check
544 * @filtered_no_pids: The list of pids not to be traced
545 * @task: The task that should be ignored if not filtered
546 *
547 * Checks if @task should be traced or not from @filtered_pids.
548 * Returns true if @task should *NOT* be traced.
549 * Returns false if @task should be traced.
550 */
551bool
552trace_ignore_this_task(struct trace_pid_list *filtered_pids,
553 struct trace_pid_list *filtered_no_pids,
554 struct task_struct *task)
555{
556 /*
557 * If filtered_no_pids is not empty, and the task's pid is listed
558 * in filtered_no_pids, then return true.
559 * Otherwise, if filtered_pids is empty, that means we can
560 * trace all tasks. If it has content, then only trace pids
561 * within filtered_pids.
562 */
563
564 return (filtered_pids &&
565 !trace_find_filtered_pid(filtered_pids, task->pid)) ||
566 (filtered_no_pids &&
567 trace_find_filtered_pid(filtered_no_pids, task->pid));
568}
569
570/**
571 * trace_filter_add_remove_task - Add or remove a task from a pid_list
572 * @pid_list: The list to modify
573 * @self: The current task for fork or NULL for exit
574 * @task: The task to add or remove
575 *
576 * If adding a task, if @self is defined, the task is only added if @self
577 * is also included in @pid_list. This happens on fork and tasks should
578 * only be added when the parent is listed. If @self is NULL, then the
579 * @task pid will be removed from the list, which would happen on exit
580 * of a task.
581 */
582void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
583 struct task_struct *self,
584 struct task_struct *task)
585{
586 if (!pid_list)
587 return;
588
589 /* For forks, we only add if the forking task is listed */
590 if (self) {
591 if (!trace_find_filtered_pid(pid_list, self->pid))
592 return;
593 }
594
595 /* Sorry, but we don't support pid_max changing after setting */
596 if (task->pid >= pid_list->pid_max)
597 return;
598
599 /* "self" is set for forks, and NULL for exits */
600 if (self)
601 set_bit(task->pid, pid_list->pids);
602 else
603 clear_bit(task->pid, pid_list->pids);
604}
605
606/**
607 * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
608 * @pid_list: The pid list to show
609 * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
610 * @pos: The position of the file
611 *
612 * This is used by the seq_file "next" operation to iterate the pids
613 * listed in a trace_pid_list structure.
614 *
615 * Returns the pid+1 as we want to display pid of zero, but NULL would
616 * stop the iteration.
617 */
618void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
619{
620 unsigned long pid = (unsigned long)v;
621
622 (*pos)++;
623
624 /* pid already is +1 of the actual previous bit */
625 pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
626
627 /* Return pid + 1 to allow zero to be represented */
628 if (pid < pid_list->pid_max)
629 return (void *)(pid + 1);
630
631 return NULL;
632}
633
634/**
635 * trace_pid_start - Used for seq_file to start reading pid lists
636 * @pid_list: The pid list to show
637 * @pos: The position of the file
638 *
639 * This is used by seq_file "start" operation to start the iteration
640 * of listing pids.
641 *
642 * Returns the pid+1 as we want to display pid of zero, but NULL would
643 * stop the iteration.
644 */
645void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
646{
647 unsigned long pid;
648 loff_t l = 0;
649
650 pid = find_first_bit(pid_list->pids, pid_list->pid_max);
651 if (pid >= pid_list->pid_max)
652 return NULL;
653
654 /* Return pid + 1 so that zero can be the exit value */
655 for (pid++; pid && l < *pos;
656 pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
657 ;
658 return (void *)pid;
659}
660
661/**
662 * trace_pid_show - show the current pid in seq_file processing
663 * @m: The seq_file structure to write into
664 * @v: A void pointer of the pid (+1) value to display
665 *
666 * Can be directly used by seq_file operations to display the current
667 * pid value.
668 */
669int trace_pid_show(struct seq_file *m, void *v)
670{
671 unsigned long pid = (unsigned long)v - 1;
672
673 seq_printf(m, "%lu\n", pid);
674 return 0;
675}
676
677/* 128 should be much more than enough */
678#define PID_BUF_SIZE 127
679
680int trace_pid_write(struct trace_pid_list *filtered_pids,
681 struct trace_pid_list **new_pid_list,
682 const char __user *ubuf, size_t cnt)
683{
684 struct trace_pid_list *pid_list;
685 struct trace_parser parser;
686 unsigned long val;
687 int nr_pids = 0;
688 ssize_t read = 0;
689 ssize_t ret = 0;
690 loff_t pos;
691 pid_t pid;
692
693 if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
694 return -ENOMEM;
695
696 /*
697 * Always recreate a new array. The write is an all or nothing
698 * operation. Always create a new array when adding new pids by
699 * the user. If the operation fails, then the current list is
700 * not modified.
701 */
702 pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
703 if (!pid_list) {
704 trace_parser_put(&parser);
705 return -ENOMEM;
706 }
707
708 pid_list->pid_max = READ_ONCE(pid_max);
709
710 /* Only truncating will shrink pid_max */
711 if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max)
712 pid_list->pid_max = filtered_pids->pid_max;
713
714 pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
715 if (!pid_list->pids) {
716 trace_parser_put(&parser);
717 kfree(pid_list);
718 return -ENOMEM;
719 }
720
721 if (filtered_pids) {
722 /* copy the current bits to the new max */
723 for_each_set_bit(pid, filtered_pids->pids,
724 filtered_pids->pid_max) {
725 set_bit(pid, pid_list->pids);
726 nr_pids++;
727 }
728 }
729
730 while (cnt > 0) {
731
732 pos = 0;
733
734 ret = trace_get_user(&parser, ubuf, cnt, &pos);
735 if (ret < 0 || !trace_parser_loaded(&parser))
736 break;
737
738 read += ret;
739 ubuf += ret;
740 cnt -= ret;
741
742 ret = -EINVAL;
743 if (kstrtoul(parser.buffer, 0, &val))
744 break;
745 if (val >= pid_list->pid_max)
746 break;
747
748 pid = (pid_t)val;
749
750 set_bit(pid, pid_list->pids);
751 nr_pids++;
752
753 trace_parser_clear(&parser);
754 ret = 0;
755 }
756 trace_parser_put(&parser);
757
758 if (ret < 0) {
759 trace_free_pid_list(pid_list);
760 return ret;
761 }
762
763 if (!nr_pids) {
764 /* Cleared the list of pids */
765 trace_free_pid_list(pid_list);
766 read = ret;
767 pid_list = NULL;
768 }
769
770 *new_pid_list = pid_list;
771
772 return read;
773}
774
775static u64 buffer_ftrace_now(struct array_buffer *buf, int cpu)
776{
777 u64 ts;
778
779 /* Early boot up does not have a buffer yet */
780 if (!buf->buffer)
781 return trace_clock_local();
782
783 ts = ring_buffer_time_stamp(buf->buffer);
784 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
785
786 return ts;
787}
788
789u64 ftrace_now(int cpu)
790{
791 return buffer_ftrace_now(&global_trace.array_buffer, cpu);
792}
793
794/**
795 * tracing_is_enabled - Show if global_trace has been enabled
796 *
797 * Shows if the global trace has been enabled or not. It uses the
798 * mirror flag "buffer_disabled" to be used in fast paths such as for
799 * the irqsoff tracer. But it may be inaccurate due to races. If you
800 * need to know the accurate state, use tracing_is_on() which is a little
801 * slower, but accurate.
802 */
803int tracing_is_enabled(void)
804{
805 /*
806 * For quick access (irqsoff uses this in fast path), just
807 * return the mirror variable of the state of the ring buffer.
808 * It's a little racy, but we don't really care.
809 */
810 smp_rmb();
811 return !global_trace.buffer_disabled;
812}
813
814/*
815 * trace_buf_size is the size in bytes that is allocated
816 * for a buffer. Note, the number of bytes is always rounded
817 * to page size.
818 *
819 * This number is purposely set to a low number of 16384.
820 * If the dump on oops happens, it will be much appreciated
821 * to not have to wait for all that output. Anyway this can be
822 * boot time and run time configurable.
823 */
824#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
825
826static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
827
828/* trace_types holds a link list of available tracers. */
829static struct tracer *trace_types __read_mostly;
830
831/*
832 * trace_types_lock is used to protect the trace_types list.
833 */
834DEFINE_MUTEX(trace_types_lock);
835
836/*
837 * serialize the access of the ring buffer
838 *
839 * ring buffer serializes readers, but it is low level protection.
840 * The validity of the events (which returns by ring_buffer_peek() ..etc)
841 * are not protected by ring buffer.
842 *
843 * The content of events may become garbage if we allow other process consumes
844 * these events concurrently:
845 * A) the page of the consumed events may become a normal page
846 * (not reader page) in ring buffer, and this page will be rewritten
847 * by events producer.
848 * B) The page of the consumed events may become a page for splice_read,
849 * and this page will be returned to system.
850 *
851 * These primitives allow multi process access to different cpu ring buffer
852 * concurrently.
853 *
854 * These primitives don't distinguish read-only and read-consume access.
855 * Multi read-only access are also serialized.
856 */
857
858#ifdef CONFIG_SMP
859static DECLARE_RWSEM(all_cpu_access_lock);
860static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
861
862static inline void trace_access_lock(int cpu)
863{
864 if (cpu == RING_BUFFER_ALL_CPUS) {
865 /* gain it for accessing the whole ring buffer. */
866 down_write(&all_cpu_access_lock);
867 } else {
868 /* gain it for accessing a cpu ring buffer. */
869
870 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
871 down_read(&all_cpu_access_lock);
872
873 /* Secondly block other access to this @cpu ring buffer. */
874 mutex_lock(&per_cpu(cpu_access_lock, cpu));
875 }
876}
877
878static inline void trace_access_unlock(int cpu)
879{
880 if (cpu == RING_BUFFER_ALL_CPUS) {
881 up_write(&all_cpu_access_lock);
882 } else {
883 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
884 up_read(&all_cpu_access_lock);
885 }
886}
887
888static inline void trace_access_lock_init(void)
889{
890 int cpu;
891
892 for_each_possible_cpu(cpu)
893 mutex_init(&per_cpu(cpu_access_lock, cpu));
894}
895
896#else
897
898static DEFINE_MUTEX(access_lock);
899
900static inline void trace_access_lock(int cpu)
901{
902 (void)cpu;
903 mutex_lock(&access_lock);
904}
905
906static inline void trace_access_unlock(int cpu)
907{
908 (void)cpu;
909 mutex_unlock(&access_lock);
910}
911
912static inline void trace_access_lock_init(void)
913{
914}
915
916#endif
917
918#ifdef CONFIG_STACKTRACE
919static void __ftrace_trace_stack(struct trace_buffer *buffer,
920 unsigned int trace_ctx,
921 int skip, struct pt_regs *regs);
922static inline void ftrace_trace_stack(struct trace_array *tr,
923 struct trace_buffer *buffer,
924 unsigned int trace_ctx,
925 int skip, struct pt_regs *regs);
926
927#else
928static inline void __ftrace_trace_stack(struct trace_buffer *buffer,
929 unsigned int trace_ctx,
930 int skip, struct pt_regs *regs)
931{
932}
933static inline void ftrace_trace_stack(struct trace_array *tr,
934 struct trace_buffer *buffer,
935 unsigned long trace_ctx,
936 int skip, struct pt_regs *regs)
937{
938}
939
940#endif
941
942static __always_inline void
943trace_event_setup(struct ring_buffer_event *event,
944 int type, unsigned int trace_ctx)
945{
946 struct trace_entry *ent = ring_buffer_event_data(event);
947
948 tracing_generic_entry_update(ent, type, trace_ctx);
949}
950
951static __always_inline struct ring_buffer_event *
952__trace_buffer_lock_reserve(struct trace_buffer *buffer,
953 int type,
954 unsigned long len,
955 unsigned int trace_ctx)
956{
957 struct ring_buffer_event *event;
958
959 event = ring_buffer_lock_reserve(buffer, len);
960 if (event != NULL)
961 trace_event_setup(event, type, trace_ctx);
962
963 return event;
964}
965
966void tracer_tracing_on(struct trace_array *tr)
967{
968 if (tr->array_buffer.buffer)
969 ring_buffer_record_on(tr->array_buffer.buffer);
970 /*
971 * This flag is looked at when buffers haven't been allocated
972 * yet, or by some tracers (like irqsoff), that just want to
973 * know if the ring buffer has been disabled, but it can handle
974 * races of where it gets disabled but we still do a record.
975 * As the check is in the fast path of the tracers, it is more
976 * important to be fast than accurate.
977 */
978 tr->buffer_disabled = 0;
979 /* Make the flag seen by readers */
980 smp_wmb();
981}
982
983/**
984 * tracing_on - enable tracing buffers
985 *
986 * This function enables tracing buffers that may have been
987 * disabled with tracing_off.
988 */
989void tracing_on(void)
990{
991 tracer_tracing_on(&global_trace);
992}
993EXPORT_SYMBOL_GPL(tracing_on);
994
995
996static __always_inline void
997__buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *event)
998{
999 __this_cpu_write(trace_taskinfo_save, true);
1000
1001 /* If this is the temp buffer, we need to commit fully */
1002 if (this_cpu_read(trace_buffered_event) == event) {
1003 /* Length is in event->array[0] */
1004 ring_buffer_write(buffer, event->array[0], &event->array[1]);
1005 /* Release the temp buffer */
1006 this_cpu_dec(trace_buffered_event_cnt);
1007 } else
1008 ring_buffer_unlock_commit(buffer, event);
1009}
1010
1011/**
1012 * __trace_puts - write a constant string into the trace buffer.
1013 * @ip: The address of the caller
1014 * @str: The constant string to write
1015 * @size: The size of the string.
1016 */
1017int __trace_puts(unsigned long ip, const char *str, int size)
1018{
1019 struct ring_buffer_event *event;
1020 struct trace_buffer *buffer;
1021 struct print_entry *entry;
1022 unsigned int trace_ctx;
1023 int alloc;
1024
1025 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
1026 return 0;
1027
1028 if (unlikely(tracing_selftest_running || tracing_disabled))
1029 return 0;
1030
1031 alloc = sizeof(*entry) + size + 2; /* possible \n added */
1032
1033 trace_ctx = tracing_gen_ctx();
1034 buffer = global_trace.array_buffer.buffer;
1035 ring_buffer_nest_start(buffer);
1036 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
1037 trace_ctx);
1038 if (!event) {
1039 size = 0;
1040 goto out;
1041 }
1042
1043 entry = ring_buffer_event_data(event);
1044 entry->ip = ip;
1045
1046 memcpy(&entry->buf, str, size);
1047
1048 /* Add a newline if necessary */
1049 if (entry->buf[size - 1] != '\n') {
1050 entry->buf[size] = '\n';
1051 entry->buf[size + 1] = '\0';
1052 } else
1053 entry->buf[size] = '\0';
1054
1055 __buffer_unlock_commit(buffer, event);
1056 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
1057 out:
1058 ring_buffer_nest_end(buffer);
1059 return size;
1060}
1061EXPORT_SYMBOL_GPL(__trace_puts);
1062
1063/**
1064 * __trace_bputs - write the pointer to a constant string into trace buffer
1065 * @ip: The address of the caller
1066 * @str: The constant string to write to the buffer to
1067 */
1068int __trace_bputs(unsigned long ip, const char *str)
1069{
1070 struct ring_buffer_event *event;
1071 struct trace_buffer *buffer;
1072 struct bputs_entry *entry;
1073 unsigned int trace_ctx;
1074 int size = sizeof(struct bputs_entry);
1075 int ret = 0;
1076
1077 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
1078 return 0;
1079
1080 if (unlikely(tracing_selftest_running || tracing_disabled))
1081 return 0;
1082
1083 trace_ctx = tracing_gen_ctx();
1084 buffer = global_trace.array_buffer.buffer;
1085
1086 ring_buffer_nest_start(buffer);
1087 event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
1088 trace_ctx);
1089 if (!event)
1090 goto out;
1091
1092 entry = ring_buffer_event_data(event);
1093 entry->ip = ip;
1094 entry->str = str;
1095
1096 __buffer_unlock_commit(buffer, event);
1097 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
1098
1099 ret = 1;
1100 out:
1101 ring_buffer_nest_end(buffer);
1102 return ret;
1103}
1104EXPORT_SYMBOL_GPL(__trace_bputs);
1105
1106#ifdef CONFIG_TRACER_SNAPSHOT
1107static void tracing_snapshot_instance_cond(struct trace_array *tr,
1108 void *cond_data)
1109{
1110 struct tracer *tracer = tr->current_trace;
1111 unsigned long flags;
1112
1113 if (in_nmi()) {
1114 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
1115 internal_trace_puts("*** snapshot is being ignored ***\n");
1116 return;
1117 }
1118
1119 if (!tr->allocated_snapshot) {
1120 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
1121 internal_trace_puts("*** stopping trace here! ***\n");
1122 tracing_off();
1123 return;
1124 }
1125
1126 /* Note, snapshot can not be used when the tracer uses it */
1127 if (tracer->use_max_tr) {
1128 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
1129 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
1130 return;
1131 }
1132
1133 local_irq_save(flags);
1134 update_max_tr(tr, current, smp_processor_id(), cond_data);
1135 local_irq_restore(flags);
1136}
1137
1138void tracing_snapshot_instance(struct trace_array *tr)
1139{
1140 tracing_snapshot_instance_cond(tr, NULL);
1141}
1142
1143/**
1144 * tracing_snapshot - take a snapshot of the current buffer.
1145 *
1146 * This causes a swap between the snapshot buffer and the current live
1147 * tracing buffer. You can use this to take snapshots of the live
1148 * trace when some condition is triggered, but continue to trace.
1149 *
1150 * Note, make sure to allocate the snapshot with either
1151 * a tracing_snapshot_alloc(), or by doing it manually
1152 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
1153 *
1154 * If the snapshot buffer is not allocated, it will stop tracing.
1155 * Basically making a permanent snapshot.
1156 */
1157void tracing_snapshot(void)
1158{
1159 struct trace_array *tr = &global_trace;
1160
1161 tracing_snapshot_instance(tr);
1162}
1163EXPORT_SYMBOL_GPL(tracing_snapshot);
1164
1165/**
1166 * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
1167 * @tr: The tracing instance to snapshot
1168 * @cond_data: The data to be tested conditionally, and possibly saved
1169 *
1170 * This is the same as tracing_snapshot() except that the snapshot is
1171 * conditional - the snapshot will only happen if the
1172 * cond_snapshot.update() implementation receiving the cond_data
1173 * returns true, which means that the trace array's cond_snapshot
1174 * update() operation used the cond_data to determine whether the
1175 * snapshot should be taken, and if it was, presumably saved it along
1176 * with the snapshot.
1177 */
1178void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1179{
1180 tracing_snapshot_instance_cond(tr, cond_data);
1181}
1182EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1183
1184/**
1185 * tracing_snapshot_cond_data - get the user data associated with a snapshot
1186 * @tr: The tracing instance
1187 *
1188 * When the user enables a conditional snapshot using
1189 * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
1190 * with the snapshot. This accessor is used to retrieve it.
1191 *
1192 * Should not be called from cond_snapshot.update(), since it takes
1193 * the tr->max_lock lock, which the code calling
1194 * cond_snapshot.update() has already done.
1195 *
1196 * Returns the cond_data associated with the trace array's snapshot.
1197 */
1198void *tracing_cond_snapshot_data(struct trace_array *tr)
1199{
1200 void *cond_data = NULL;
1201
1202 arch_spin_lock(&tr->max_lock);
1203
1204 if (tr->cond_snapshot)
1205 cond_data = tr->cond_snapshot->cond_data;
1206
1207 arch_spin_unlock(&tr->max_lock);
1208
1209 return cond_data;
1210}
1211EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1212
1213static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
1214 struct array_buffer *size_buf, int cpu_id);
1215static void set_buffer_entries(struct array_buffer *buf, unsigned long val);
1216
1217int tracing_alloc_snapshot_instance(struct trace_array *tr)
1218{
1219 int ret;
1220
1221 if (!tr->allocated_snapshot) {
1222
1223 /* allocate spare buffer */
1224 ret = resize_buffer_duplicate_size(&tr->max_buffer,
1225 &tr->array_buffer, RING_BUFFER_ALL_CPUS);
1226 if (ret < 0)
1227 return ret;
1228
1229 tr->allocated_snapshot = true;
1230 }
1231
1232 return 0;
1233}
1234
1235static void free_snapshot(struct trace_array *tr)
1236{
1237 /*
1238 * We don't free the ring buffer. instead, resize it because
1239 * The max_tr ring buffer has some state (e.g. ring->clock) and
1240 * we want preserve it.
1241 */
1242 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
1243 set_buffer_entries(&tr->max_buffer, 1);
1244 tracing_reset_online_cpus(&tr->max_buffer);
1245 tr->allocated_snapshot = false;
1246}
1247
1248/**
1249 * tracing_alloc_snapshot - allocate snapshot buffer.
1250 *
1251 * This only allocates the snapshot buffer if it isn't already
1252 * allocated - it doesn't also take a snapshot.
1253 *
1254 * This is meant to be used in cases where the snapshot buffer needs
1255 * to be set up for events that can't sleep but need to be able to
1256 * trigger a snapshot.
1257 */
1258int tracing_alloc_snapshot(void)
1259{
1260 struct trace_array *tr = &global_trace;
1261 int ret;
1262
1263 ret = tracing_alloc_snapshot_instance(tr);
1264 WARN_ON(ret < 0);
1265
1266 return ret;
1267}
1268EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1269
1270/**
1271 * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
1272 *
1273 * This is similar to tracing_snapshot(), but it will allocate the
1274 * snapshot buffer if it isn't already allocated. Use this only
1275 * where it is safe to sleep, as the allocation may sleep.
1276 *
1277 * This causes a swap between the snapshot buffer and the current live
1278 * tracing buffer. You can use this to take snapshots of the live
1279 * trace when some condition is triggered, but continue to trace.
1280 */
1281void tracing_snapshot_alloc(void)
1282{
1283 int ret;
1284
1285 ret = tracing_alloc_snapshot();
1286 if (ret < 0)
1287 return;
1288
1289 tracing_snapshot();
1290}
1291EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1292
1293/**
1294 * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
1295 * @tr: The tracing instance
1296 * @cond_data: User data to associate with the snapshot
1297 * @update: Implementation of the cond_snapshot update function
1298 *
1299 * Check whether the conditional snapshot for the given instance has
1300 * already been enabled, or if the current tracer is already using a
1301 * snapshot; if so, return -EBUSY, else create a cond_snapshot and
1302 * save the cond_data and update function inside.
1303 *
1304 * Returns 0 if successful, error otherwise.
1305 */
1306int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
1307 cond_update_fn_t update)
1308{
1309 struct cond_snapshot *cond_snapshot;
1310 int ret = 0;
1311
1312 cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
1313 if (!cond_snapshot)
1314 return -ENOMEM;
1315
1316 cond_snapshot->cond_data = cond_data;
1317 cond_snapshot->update = update;
1318
1319 mutex_lock(&trace_types_lock);
1320
1321 ret = tracing_alloc_snapshot_instance(tr);
1322 if (ret)
1323 goto fail_unlock;
1324
1325 if (tr->current_trace->use_max_tr) {
1326 ret = -EBUSY;
1327 goto fail_unlock;
1328 }
1329
1330 /*
1331 * The cond_snapshot can only change to NULL without the
1332 * trace_types_lock. We don't care if we race with it going
1333 * to NULL, but we want to make sure that it's not set to
1334 * something other than NULL when we get here, which we can
1335 * do safely with only holding the trace_types_lock and not
1336 * having to take the max_lock.
1337 */
1338 if (tr->cond_snapshot) {
1339 ret = -EBUSY;
1340 goto fail_unlock;
1341 }
1342
1343 arch_spin_lock(&tr->max_lock);
1344 tr->cond_snapshot = cond_snapshot;
1345 arch_spin_unlock(&tr->max_lock);
1346
1347 mutex_unlock(&trace_types_lock);
1348
1349 return ret;
1350
1351 fail_unlock:
1352 mutex_unlock(&trace_types_lock);
1353 kfree(cond_snapshot);
1354 return ret;
1355}
1356EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1357
1358/**
1359 * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
1360 * @tr: The tracing instance
1361 *
1362 * Check whether the conditional snapshot for the given instance is
1363 * enabled; if so, free the cond_snapshot associated with it,
1364 * otherwise return -EINVAL.
1365 *
1366 * Returns 0 if successful, error otherwise.
1367 */
1368int tracing_snapshot_cond_disable(struct trace_array *tr)
1369{
1370 int ret = 0;
1371
1372 arch_spin_lock(&tr->max_lock);
1373
1374 if (!tr->cond_snapshot)
1375 ret = -EINVAL;
1376 else {
1377 kfree(tr->cond_snapshot);
1378 tr->cond_snapshot = NULL;
1379 }
1380
1381 arch_spin_unlock(&tr->max_lock);
1382
1383 return ret;
1384}
1385EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1386#else
1387void tracing_snapshot(void)
1388{
1389 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
1390}
1391EXPORT_SYMBOL_GPL(tracing_snapshot);
1392void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1393{
1394 WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
1395}
1396EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1397int tracing_alloc_snapshot(void)
1398{
1399 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
1400 return -ENODEV;
1401}
1402EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1403void tracing_snapshot_alloc(void)
1404{
1405 /* Give warning */
1406 tracing_snapshot();
1407}
1408EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1409void *tracing_cond_snapshot_data(struct trace_array *tr)
1410{
1411 return NULL;
1412}
1413EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1414int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
1415{
1416 return -ENODEV;
1417}
1418EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1419int tracing_snapshot_cond_disable(struct trace_array *tr)
1420{
1421 return false;
1422}
1423EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1424#endif /* CONFIG_TRACER_SNAPSHOT */
1425
1426void tracer_tracing_off(struct trace_array *tr)
1427{
1428 if (tr->array_buffer.buffer)
1429 ring_buffer_record_off(tr->array_buffer.buffer);
1430 /*
1431 * This flag is looked at when buffers haven't been allocated
1432 * yet, or by some tracers (like irqsoff), that just want to
1433 * know if the ring buffer has been disabled, but it can handle
1434 * races of where it gets disabled but we still do a record.
1435 * As the check is in the fast path of the tracers, it is more
1436 * important to be fast than accurate.
1437 */
1438 tr->buffer_disabled = 1;
1439 /* Make the flag seen by readers */
1440 smp_wmb();
1441}
1442
1443/**
1444 * tracing_off - turn off tracing buffers
1445 *
1446 * This function stops the tracing buffers from recording data.
1447 * It does not disable any overhead the tracers themselves may
1448 * be causing. This function simply causes all recording to
1449 * the ring buffers to fail.
1450 */
1451void tracing_off(void)
1452{
1453 tracer_tracing_off(&global_trace);
1454}
1455EXPORT_SYMBOL_GPL(tracing_off);
1456
1457void disable_trace_on_warning(void)
1458{
1459 if (__disable_trace_on_warning) {
1460 trace_array_printk_buf(global_trace.array_buffer.buffer, _THIS_IP_,
1461 "Disabling tracing due to warning\n");
1462 tracing_off();
1463 }
1464}
1465
1466/**
1467 * tracer_tracing_is_on - show real state of ring buffer enabled
1468 * @tr : the trace array to know if ring buffer is enabled
1469 *
1470 * Shows real state of the ring buffer if it is enabled or not.
1471 */
1472bool tracer_tracing_is_on(struct trace_array *tr)
1473{
1474 if (tr->array_buffer.buffer)
1475 return ring_buffer_record_is_on(tr->array_buffer.buffer);
1476 return !tr->buffer_disabled;
1477}
1478
1479/**
1480 * tracing_is_on - show state of ring buffers enabled
1481 */
1482int tracing_is_on(void)
1483{
1484 return tracer_tracing_is_on(&global_trace);
1485}
1486EXPORT_SYMBOL_GPL(tracing_is_on);
1487
1488static int __init set_buf_size(char *str)
1489{
1490 unsigned long buf_size;
1491
1492 if (!str)
1493 return 0;
1494 buf_size = memparse(str, &str);
1495 /* nr_entries can not be zero */
1496 if (buf_size == 0)
1497 return 0;
1498 trace_buf_size = buf_size;
1499 return 1;
1500}
1501__setup("trace_buf_size=", set_buf_size);
1502
1503static int __init set_tracing_thresh(char *str)
1504{
1505 unsigned long threshold;
1506 int ret;
1507
1508 if (!str)
1509 return 0;
1510 ret = kstrtoul(str, 0, &threshold);
1511 if (ret < 0)
1512 return 0;
1513 tracing_thresh = threshold * 1000;
1514 return 1;
1515}
1516__setup("tracing_thresh=", set_tracing_thresh);
1517
1518unsigned long nsecs_to_usecs(unsigned long nsecs)
1519{
1520 return nsecs / 1000;
1521}
1522
1523/*
1524 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
1525 * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
1526 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
1527 * of strings in the order that the evals (enum) were defined.
1528 */
1529#undef C
1530#define C(a, b) b
1531
1532/* These must match the bit positions in trace_iterator_flags */
1533static const char *trace_options[] = {
1534 TRACE_FLAGS
1535 NULL
1536};
1537
1538static struct {
1539 u64 (*func)(void);
1540 const char *name;
1541 int in_ns; /* is this clock in nanoseconds? */
1542} trace_clocks[] = {
1543 { trace_clock_local, "local", 1 },
1544 { trace_clock_global, "global", 1 },
1545 { trace_clock_counter, "counter", 0 },
1546 { trace_clock_jiffies, "uptime", 0 },
1547 { trace_clock, "perf", 1 },
1548 { ktime_get_mono_fast_ns, "mono", 1 },
1549 { ktime_get_raw_fast_ns, "mono_raw", 1 },
1550 { ktime_get_boot_fast_ns, "boot", 1 },
1551 ARCH_TRACE_CLOCKS
1552};
1553
1554bool trace_clock_in_ns(struct trace_array *tr)
1555{
1556 if (trace_clocks[tr->clock_id].in_ns)
1557 return true;
1558
1559 return false;
1560}
1561
1562/*
1563 * trace_parser_get_init - gets the buffer for trace parser
1564 */
1565int trace_parser_get_init(struct trace_parser *parser, int size)
1566{
1567 memset(parser, 0, sizeof(*parser));
1568
1569 parser->buffer = kmalloc(size, GFP_KERNEL);
1570 if (!parser->buffer)
1571 return 1;
1572
1573 parser->size = size;
1574 return 0;
1575}
1576
1577/*
1578 * trace_parser_put - frees the buffer for trace parser
1579 */
1580void trace_parser_put(struct trace_parser *parser)
1581{
1582 kfree(parser->buffer);
1583 parser->buffer = NULL;
1584}
1585
1586/*
1587 * trace_get_user - reads the user input string separated by space
1588 * (matched by isspace(ch))
1589 *
1590 * For each string found the 'struct trace_parser' is updated,
1591 * and the function returns.
1592 *
1593 * Returns number of bytes read.
1594 *
1595 * See kernel/trace/trace.h for 'struct trace_parser' details.
1596 */
1597int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1598 size_t cnt, loff_t *ppos)
1599{
1600 char ch;
1601 size_t read = 0;
1602 ssize_t ret;
1603
1604 if (!*ppos)
1605 trace_parser_clear(parser);
1606
1607 ret = get_user(ch, ubuf++);
1608 if (ret)
1609 goto out;
1610
1611 read++;
1612 cnt--;
1613
1614 /*
1615 * The parser is not finished with the last write,
1616 * continue reading the user input without skipping spaces.
1617 */
1618 if (!parser->cont) {
1619 /* skip white space */
1620 while (cnt && isspace(ch)) {
1621 ret = get_user(ch, ubuf++);
1622 if (ret)
1623 goto out;
1624 read++;
1625 cnt--;
1626 }
1627
1628 parser->idx = 0;
1629
1630 /* only spaces were written */
1631 if (isspace(ch) || !ch) {
1632 *ppos += read;
1633 ret = read;
1634 goto out;
1635 }
1636 }
1637
1638 /* read the non-space input */
1639 while (cnt && !isspace(ch) && ch) {
1640 if (parser->idx < parser->size - 1)
1641 parser->buffer[parser->idx++] = ch;
1642 else {
1643 ret = -EINVAL;
1644 goto out;
1645 }
1646 ret = get_user(ch, ubuf++);
1647 if (ret)
1648 goto out;
1649 read++;
1650 cnt--;
1651 }
1652
1653 /* We either got finished input or we have to wait for another call. */
1654 if (isspace(ch) || !ch) {
1655 parser->buffer[parser->idx] = 0;
1656 parser->cont = false;
1657 } else if (parser->idx < parser->size - 1) {
1658 parser->cont = true;
1659 parser->buffer[parser->idx++] = ch;
1660 /* Make sure the parsed string always terminates with '\0'. */
1661 parser->buffer[parser->idx] = 0;
1662 } else {
1663 ret = -EINVAL;
1664 goto out;
1665 }
1666
1667 *ppos += read;
1668 ret = read;
1669
1670out:
1671 return ret;
1672}
1673
1674/* TODO add a seq_buf_to_buffer() */
1675static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1676{
1677 int len;
1678
1679 if (trace_seq_used(s) <= s->seq.readpos)
1680 return -EBUSY;
1681
1682 len = trace_seq_used(s) - s->seq.readpos;
1683 if (cnt > len)
1684 cnt = len;
1685 memcpy(buf, s->buffer + s->seq.readpos, cnt);
1686
1687 s->seq.readpos += cnt;
1688 return cnt;
1689}
1690
1691unsigned long __read_mostly tracing_thresh;
1692static const struct file_operations tracing_max_lat_fops;
1693
1694#ifdef LATENCY_FS_NOTIFY
1695
1696static struct workqueue_struct *fsnotify_wq;
1697
1698static void latency_fsnotify_workfn(struct work_struct *work)
1699{
1700 struct trace_array *tr = container_of(work, struct trace_array,
1701 fsnotify_work);
1702 fsnotify_inode(tr->d_max_latency->d_inode, FS_MODIFY);
1703}
1704
1705static void latency_fsnotify_workfn_irq(struct irq_work *iwork)
1706{
1707 struct trace_array *tr = container_of(iwork, struct trace_array,
1708 fsnotify_irqwork);
1709 queue_work(fsnotify_wq, &tr->fsnotify_work);
1710}
1711
1712static void trace_create_maxlat_file(struct trace_array *tr,
1713 struct dentry *d_tracer)
1714{
1715 INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
1716 init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
1717 tr->d_max_latency = trace_create_file("tracing_max_latency", 0644,
1718 d_tracer, &tr->max_latency,
1719 &tracing_max_lat_fops);
1720}
1721
1722__init static int latency_fsnotify_init(void)
1723{
1724 fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
1725 WQ_UNBOUND | WQ_HIGHPRI, 0);
1726 if (!fsnotify_wq) {
1727 pr_err("Unable to allocate tr_max_lat_wq\n");
1728 return -ENOMEM;
1729 }
1730 return 0;
1731}
1732
1733late_initcall_sync(latency_fsnotify_init);
1734
1735void latency_fsnotify(struct trace_array *tr)
1736{
1737 if (!fsnotify_wq)
1738 return;
1739 /*
1740 * We cannot call queue_work(&tr->fsnotify_work) from here because it's
1741 * possible that we are called from __schedule() or do_idle(), which
1742 * could cause a deadlock.
1743 */
1744 irq_work_queue(&tr->fsnotify_irqwork);
1745}
1746
1747#elif defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER) \
1748 || defined(CONFIG_OSNOISE_TRACER)
1749
1750#define trace_create_maxlat_file(tr, d_tracer) \
1751 trace_create_file("tracing_max_latency", 0644, d_tracer, \
1752 &tr->max_latency, &tracing_max_lat_fops)
1753
1754#else
1755#define trace_create_maxlat_file(tr, d_tracer) do { } while (0)
1756#endif
1757
1758#ifdef CONFIG_TRACER_MAX_TRACE
1759/*
1760 * Copy the new maximum trace into the separate maximum-trace
1761 * structure. (this way the maximum trace is permanently saved,
1762 * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
1763 */
1764static void
1765__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1766{
1767 struct array_buffer *trace_buf = &tr->array_buffer;
1768 struct array_buffer *max_buf = &tr->max_buffer;
1769 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1770 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1771
1772 max_buf->cpu = cpu;
1773 max_buf->time_start = data->preempt_timestamp;
1774
1775 max_data->saved_latency = tr->max_latency;
1776 max_data->critical_start = data->critical_start;
1777 max_data->critical_end = data->critical_end;
1778
1779 strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1780 max_data->pid = tsk->pid;
1781 /*
1782 * If tsk == current, then use current_uid(), as that does not use
1783 * RCU. The irq tracer can be called out of RCU scope.
1784 */
1785 if (tsk == current)
1786 max_data->uid = current_uid();
1787 else
1788 max_data->uid = task_uid(tsk);
1789
1790 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1791 max_data->policy = tsk->policy;
1792 max_data->rt_priority = tsk->rt_priority;
1793
1794 /* record this tasks comm */
1795 tracing_record_cmdline(tsk);
1796 latency_fsnotify(tr);
1797}
1798
1799/**
1800 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1801 * @tr: tracer
1802 * @tsk: the task with the latency
1803 * @cpu: The cpu that initiated the trace.
1804 * @cond_data: User data associated with a conditional snapshot
1805 *
1806 * Flip the buffers between the @tr and the max_tr and record information
1807 * about which task was the cause of this latency.
1808 */
1809void
1810update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
1811 void *cond_data)
1812{
1813 if (tr->stop_count)
1814 return;
1815
1816 WARN_ON_ONCE(!irqs_disabled());
1817
1818 if (!tr->allocated_snapshot) {
1819 /* Only the nop tracer should hit this when disabling */
1820 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1821 return;
1822 }
1823
1824 arch_spin_lock(&tr->max_lock);
1825
1826 /* Inherit the recordable setting from array_buffer */
1827 if (ring_buffer_record_is_set_on(tr->array_buffer.buffer))
1828 ring_buffer_record_on(tr->max_buffer.buffer);
1829 else
1830 ring_buffer_record_off(tr->max_buffer.buffer);
1831
1832#ifdef CONFIG_TRACER_SNAPSHOT
1833 if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data))
1834 goto out_unlock;
1835#endif
1836 swap(tr->array_buffer.buffer, tr->max_buffer.buffer);
1837
1838 __update_max_tr(tr, tsk, cpu);
1839
1840 out_unlock:
1841 arch_spin_unlock(&tr->max_lock);
1842}
1843
1844/**
1845 * update_max_tr_single - only copy one trace over, and reset the rest
1846 * @tr: tracer
1847 * @tsk: task with the latency
1848 * @cpu: the cpu of the buffer to copy.
1849 *
1850 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1851 */
1852void
1853update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1854{
1855 int ret;
1856
1857 if (tr->stop_count)
1858 return;
1859
1860 WARN_ON_ONCE(!irqs_disabled());
1861 if (!tr->allocated_snapshot) {
1862 /* Only the nop tracer should hit this when disabling */
1863 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1864 return;
1865 }
1866
1867 arch_spin_lock(&tr->max_lock);
1868
1869 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu);
1870
1871 if (ret == -EBUSY) {
1872 /*
1873 * We failed to swap the buffer due to a commit taking
1874 * place on this CPU. We fail to record, but we reset
1875 * the max trace buffer (no one writes directly to it)
1876 * and flag that it failed.
1877 */
1878 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1879 "Failed to swap buffers due to commit in progress\n");
1880 }
1881
1882 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1883
1884 __update_max_tr(tr, tsk, cpu);
1885 arch_spin_unlock(&tr->max_lock);
1886}
1887#endif /* CONFIG_TRACER_MAX_TRACE */
1888
1889static int wait_on_pipe(struct trace_iterator *iter, int full)
1890{
1891 /* Iterators are static, they should be filled or empty */
1892 if (trace_buffer_iter(iter, iter->cpu_file))
1893 return 0;
1894
1895 return ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file,
1896 full);
1897}
1898
1899#ifdef CONFIG_FTRACE_STARTUP_TEST
1900static bool selftests_can_run;
1901
1902struct trace_selftests {
1903 struct list_head list;
1904 struct tracer *type;
1905};
1906
1907static LIST_HEAD(postponed_selftests);
1908
1909static int save_selftest(struct tracer *type)
1910{
1911 struct trace_selftests *selftest;
1912
1913 selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
1914 if (!selftest)
1915 return -ENOMEM;
1916
1917 selftest->type = type;
1918 list_add(&selftest->list, &postponed_selftests);
1919 return 0;
1920}
1921
1922static int run_tracer_selftest(struct tracer *type)
1923{
1924 struct trace_array *tr = &global_trace;
1925 struct tracer *saved_tracer = tr->current_trace;
1926 int ret;
1927
1928 if (!type->selftest || tracing_selftest_disabled)
1929 return 0;
1930
1931 /*
1932 * If a tracer registers early in boot up (before scheduling is
1933 * initialized and such), then do not run its selftests yet.
1934 * Instead, run it a little later in the boot process.
1935 */
1936 if (!selftests_can_run)
1937 return save_selftest(type);
1938
1939 if (!tracing_is_on()) {
1940 pr_warn("Selftest for tracer %s skipped due to tracing disabled\n",
1941 type->name);
1942 return 0;
1943 }
1944
1945 /*
1946 * Run a selftest on this tracer.
1947 * Here we reset the trace buffer, and set the current
1948 * tracer to be this tracer. The tracer can then run some
1949 * internal tracing to verify that everything is in order.
1950 * If we fail, we do not register this tracer.
1951 */
1952 tracing_reset_online_cpus(&tr->array_buffer);
1953
1954 tr->current_trace = type;
1955
1956#ifdef CONFIG_TRACER_MAX_TRACE
1957 if (type->use_max_tr) {
1958 /* If we expanded the buffers, make sure the max is expanded too */
1959 if (ring_buffer_expanded)
1960 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
1961 RING_BUFFER_ALL_CPUS);
1962 tr->allocated_snapshot = true;
1963 }
1964#endif
1965
1966 /* the test is responsible for initializing and enabling */
1967 pr_info("Testing tracer %s: ", type->name);
1968 ret = type->selftest(type, tr);
1969 /* the test is responsible for resetting too */
1970 tr->current_trace = saved_tracer;
1971 if (ret) {
1972 printk(KERN_CONT "FAILED!\n");
1973 /* Add the warning after printing 'FAILED' */
1974 WARN_ON(1);
1975 return -1;
1976 }
1977 /* Only reset on passing, to avoid touching corrupted buffers */
1978 tracing_reset_online_cpus(&tr->array_buffer);
1979
1980#ifdef CONFIG_TRACER_MAX_TRACE
1981 if (type->use_max_tr) {
1982 tr->allocated_snapshot = false;
1983
1984 /* Shrink the max buffer again */
1985 if (ring_buffer_expanded)
1986 ring_buffer_resize(tr->max_buffer.buffer, 1,
1987 RING_BUFFER_ALL_CPUS);
1988 }
1989#endif
1990
1991 printk(KERN_CONT "PASSED\n");
1992 return 0;
1993}
1994
1995static __init int init_trace_selftests(void)
1996{
1997 struct trace_selftests *p, *n;
1998 struct tracer *t, **last;
1999 int ret;
2000
2001 selftests_can_run = true;
2002
2003 mutex_lock(&trace_types_lock);
2004
2005 if (list_empty(&postponed_selftests))
2006 goto out;
2007
2008 pr_info("Running postponed tracer tests:\n");
2009
2010 tracing_selftest_running = true;
2011 list_for_each_entry_safe(p, n, &postponed_selftests, list) {
2012 /* This loop can take minutes when sanitizers are enabled, so
2013 * lets make sure we allow RCU processing.
2014 */
2015 cond_resched();
2016 ret = run_tracer_selftest(p->type);
2017 /* If the test fails, then warn and remove from available_tracers */
2018 if (ret < 0) {
2019 WARN(1, "tracer: %s failed selftest, disabling\n",
2020 p->type->name);
2021 last = &trace_types;
2022 for (t = trace_types; t; t = t->next) {
2023 if (t == p->type) {
2024 *last = t->next;
2025 break;
2026 }
2027 last = &t->next;
2028 }
2029 }
2030 list_del(&p->list);
2031 kfree(p);
2032 }
2033 tracing_selftest_running = false;
2034
2035 out:
2036 mutex_unlock(&trace_types_lock);
2037
2038 return 0;
2039}
2040core_initcall(init_trace_selftests);
2041#else
2042static inline int run_tracer_selftest(struct tracer *type)
2043{
2044 return 0;
2045}
2046#endif /* CONFIG_FTRACE_STARTUP_TEST */
2047
2048static void add_tracer_options(struct trace_array *tr, struct tracer *t);
2049
2050static void __init apply_trace_boot_options(void);
2051
2052/**
2053 * register_tracer - register a tracer with the ftrace system.
2054 * @type: the plugin for the tracer
2055 *
2056 * Register a new plugin tracer.
2057 */
2058int __init register_tracer(struct tracer *type)
2059{
2060 struct tracer *t;
2061 int ret = 0;
2062
2063 if (!type->name) {
2064 pr_info("Tracer must have a name\n");
2065 return -1;
2066 }
2067
2068 if (strlen(type->name) >= MAX_TRACER_SIZE) {
2069 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
2070 return -1;
2071 }
2072
2073 if (security_locked_down(LOCKDOWN_TRACEFS)) {
2074 pr_warn("Can not register tracer %s due to lockdown\n",
2075 type->name);
2076 return -EPERM;
2077 }
2078
2079 mutex_lock(&trace_types_lock);
2080
2081 tracing_selftest_running = true;
2082
2083 for (t = trace_types; t; t = t->next) {
2084 if (strcmp(type->name, t->name) == 0) {
2085 /* already found */
2086 pr_info("Tracer %s already registered\n",
2087 type->name);
2088 ret = -1;
2089 goto out;
2090 }
2091 }
2092
2093 if (!type->set_flag)
2094 type->set_flag = &dummy_set_flag;
2095 if (!type->flags) {
2096 /*allocate a dummy tracer_flags*/
2097 type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
2098 if (!type->flags) {
2099 ret = -ENOMEM;
2100 goto out;
2101 }
2102 type->flags->val = 0;
2103 type->flags->opts = dummy_tracer_opt;
2104 } else
2105 if (!type->flags->opts)
2106 type->flags->opts = dummy_tracer_opt;
2107
2108 /* store the tracer for __set_tracer_option */
2109 type->flags->trace = type;
2110
2111 ret = run_tracer_selftest(type);
2112 if (ret < 0)
2113 goto out;
2114
2115 type->next = trace_types;
2116 trace_types = type;
2117 add_tracer_options(&global_trace, type);
2118
2119 out:
2120 tracing_selftest_running = false;
2121 mutex_unlock(&trace_types_lock);
2122
2123 if (ret || !default_bootup_tracer)
2124 goto out_unlock;
2125
2126 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
2127 goto out_unlock;
2128
2129 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
2130 /* Do we want this tracer to start on bootup? */
2131 tracing_set_tracer(&global_trace, type->name);
2132 default_bootup_tracer = NULL;
2133
2134 apply_trace_boot_options();
2135
2136 /* disable other selftests, since this will break it. */
2137 disable_tracing_selftest("running a tracer");
2138
2139 out_unlock:
2140 return ret;
2141}
2142
2143static void tracing_reset_cpu(struct array_buffer *buf, int cpu)
2144{
2145 struct trace_buffer *buffer = buf->buffer;
2146
2147 if (!buffer)
2148 return;
2149
2150 ring_buffer_record_disable(buffer);
2151
2152 /* Make sure all commits have finished */
2153 synchronize_rcu();
2154 ring_buffer_reset_cpu(buffer, cpu);
2155
2156 ring_buffer_record_enable(buffer);
2157}
2158
2159void tracing_reset_online_cpus(struct array_buffer *buf)
2160{
2161 struct trace_buffer *buffer = buf->buffer;
2162
2163 if (!buffer)
2164 return;
2165
2166 ring_buffer_record_disable(buffer);
2167
2168 /* Make sure all commits have finished */
2169 synchronize_rcu();
2170
2171 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
2172
2173 ring_buffer_reset_online_cpus(buffer);
2174
2175 ring_buffer_record_enable(buffer);
2176}
2177
2178/* Must have trace_types_lock held */
2179void tracing_reset_all_online_cpus(void)
2180{
2181 struct trace_array *tr;
2182
2183 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2184 if (!tr->clear_trace)
2185 continue;
2186 tr->clear_trace = false;
2187 tracing_reset_online_cpus(&tr->array_buffer);
2188#ifdef CONFIG_TRACER_MAX_TRACE
2189 tracing_reset_online_cpus(&tr->max_buffer);
2190#endif
2191 }
2192}
2193
2194/*
2195 * The tgid_map array maps from pid to tgid; i.e. the value stored at index i
2196 * is the tgid last observed corresponding to pid=i.
2197 */
2198static int *tgid_map;
2199
2200/* The maximum valid index into tgid_map. */
2201static size_t tgid_map_max;
2202
2203#define SAVED_CMDLINES_DEFAULT 128
2204#define NO_CMDLINE_MAP UINT_MAX
2205static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
2206struct saved_cmdlines_buffer {
2207 unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
2208 unsigned *map_cmdline_to_pid;
2209 unsigned cmdline_num;
2210 int cmdline_idx;
2211 char *saved_cmdlines;
2212};
2213static struct saved_cmdlines_buffer *savedcmd;
2214
2215static inline char *get_saved_cmdlines(int idx)
2216{
2217 return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
2218}
2219
2220static inline void set_cmdline(int idx, const char *cmdline)
2221{
2222 strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
2223}
2224
2225static int allocate_cmdlines_buffer(unsigned int val,
2226 struct saved_cmdlines_buffer *s)
2227{
2228 s->map_cmdline_to_pid = kmalloc_array(val,
2229 sizeof(*s->map_cmdline_to_pid),
2230 GFP_KERNEL);
2231 if (!s->map_cmdline_to_pid)
2232 return -ENOMEM;
2233
2234 s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL);
2235 if (!s->saved_cmdlines) {
2236 kfree(s->map_cmdline_to_pid);
2237 return -ENOMEM;
2238 }
2239
2240 s->cmdline_idx = 0;
2241 s->cmdline_num = val;
2242 memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
2243 sizeof(s->map_pid_to_cmdline));
2244 memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
2245 val * sizeof(*s->map_cmdline_to_pid));
2246
2247 return 0;
2248}
2249
2250static int trace_create_savedcmd(void)
2251{
2252 int ret;
2253
2254 savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
2255 if (!savedcmd)
2256 return -ENOMEM;
2257
2258 ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
2259 if (ret < 0) {
2260 kfree(savedcmd);
2261 savedcmd = NULL;
2262 return -ENOMEM;
2263 }
2264
2265 return 0;
2266}
2267
2268int is_tracing_stopped(void)
2269{
2270 return global_trace.stop_count;
2271}
2272
2273/**
2274 * tracing_start - quick start of the tracer
2275 *
2276 * If tracing is enabled but was stopped by tracing_stop,
2277 * this will start the tracer back up.
2278 */
2279void tracing_start(void)
2280{
2281 struct trace_buffer *buffer;
2282 unsigned long flags;
2283
2284 if (tracing_disabled)
2285 return;
2286
2287 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
2288 if (--global_trace.stop_count) {
2289 if (global_trace.stop_count < 0) {
2290 /* Someone screwed up their debugging */
2291 WARN_ON_ONCE(1);
2292 global_trace.stop_count = 0;
2293 }
2294 goto out;
2295 }
2296
2297 /* Prevent the buffers from switching */
2298 arch_spin_lock(&global_trace.max_lock);
2299
2300 buffer = global_trace.array_buffer.buffer;
2301 if (buffer)
2302 ring_buffer_record_enable(buffer);
2303
2304#ifdef CONFIG_TRACER_MAX_TRACE
2305 buffer = global_trace.max_buffer.buffer;
2306 if (buffer)
2307 ring_buffer_record_enable(buffer);
2308#endif
2309
2310 arch_spin_unlock(&global_trace.max_lock);
2311
2312 out:
2313 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
2314}
2315
2316static void tracing_start_tr(struct trace_array *tr)
2317{
2318 struct trace_buffer *buffer;
2319 unsigned long flags;
2320
2321 if (tracing_disabled)
2322 return;
2323
2324 /* If global, we need to also start the max tracer */
2325 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
2326 return tracing_start();
2327
2328 raw_spin_lock_irqsave(&tr->start_lock, flags);
2329
2330 if (--tr->stop_count) {
2331 if (tr->stop_count < 0) {
2332 /* Someone screwed up their debugging */
2333 WARN_ON_ONCE(1);
2334 tr->stop_count = 0;
2335 }
2336 goto out;
2337 }
2338
2339 buffer = tr->array_buffer.buffer;
2340 if (buffer)
2341 ring_buffer_record_enable(buffer);
2342
2343 out:
2344 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2345}
2346
2347/**
2348 * tracing_stop - quick stop of the tracer
2349 *
2350 * Light weight way to stop tracing. Use in conjunction with
2351 * tracing_start.
2352 */
2353void tracing_stop(void)
2354{
2355 struct trace_buffer *buffer;
2356 unsigned long flags;
2357
2358 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
2359 if (global_trace.stop_count++)
2360 goto out;
2361
2362 /* Prevent the buffers from switching */
2363 arch_spin_lock(&global_trace.max_lock);
2364
2365 buffer = global_trace.array_buffer.buffer;
2366 if (buffer)
2367 ring_buffer_record_disable(buffer);
2368
2369#ifdef CONFIG_TRACER_MAX_TRACE
2370 buffer = global_trace.max_buffer.buffer;
2371 if (buffer)
2372 ring_buffer_record_disable(buffer);
2373#endif
2374
2375 arch_spin_unlock(&global_trace.max_lock);
2376
2377 out:
2378 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
2379}
2380
2381static void tracing_stop_tr(struct trace_array *tr)
2382{
2383 struct trace_buffer *buffer;
2384 unsigned long flags;
2385
2386 /* If global, we need to also stop the max tracer */
2387 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
2388 return tracing_stop();
2389
2390 raw_spin_lock_irqsave(&tr->start_lock, flags);
2391 if (tr->stop_count++)
2392 goto out;
2393
2394 buffer = tr->array_buffer.buffer;
2395 if (buffer)
2396 ring_buffer_record_disable(buffer);
2397
2398 out:
2399 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2400}
2401
2402static int trace_save_cmdline(struct task_struct *tsk)
2403{
2404 unsigned tpid, idx;
2405
2406 /* treat recording of idle task as a success */
2407 if (!tsk->pid)
2408 return 1;
2409
2410 tpid = tsk->pid & (PID_MAX_DEFAULT - 1);
2411
2412 /*
2413 * It's not the end of the world if we don't get
2414 * the lock, but we also don't want to spin
2415 * nor do we want to disable interrupts,
2416 * so if we miss here, then better luck next time.
2417 */
2418 if (!arch_spin_trylock(&trace_cmdline_lock))
2419 return 0;
2420
2421 idx = savedcmd->map_pid_to_cmdline[tpid];
2422 if (idx == NO_CMDLINE_MAP) {
2423 idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
2424
2425 savedcmd->map_pid_to_cmdline[tpid] = idx;
2426 savedcmd->cmdline_idx = idx;
2427 }
2428
2429 savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
2430 set_cmdline(idx, tsk->comm);
2431
2432 arch_spin_unlock(&trace_cmdline_lock);
2433
2434 return 1;
2435}
2436
2437static void __trace_find_cmdline(int pid, char comm[])
2438{
2439 unsigned map;
2440 int tpid;
2441
2442 if (!pid) {
2443 strcpy(comm, "<idle>");
2444 return;
2445 }
2446
2447 if (WARN_ON_ONCE(pid < 0)) {
2448 strcpy(comm, "<XXX>");
2449 return;
2450 }
2451
2452 tpid = pid & (PID_MAX_DEFAULT - 1);
2453 map = savedcmd->map_pid_to_cmdline[tpid];
2454 if (map != NO_CMDLINE_MAP) {
2455 tpid = savedcmd->map_cmdline_to_pid[map];
2456 if (tpid == pid) {
2457 strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
2458 return;
2459 }
2460 }
2461 strcpy(comm, "<...>");
2462}
2463
2464void trace_find_cmdline(int pid, char comm[])
2465{
2466 preempt_disable();
2467 arch_spin_lock(&trace_cmdline_lock);
2468
2469 __trace_find_cmdline(pid, comm);
2470
2471 arch_spin_unlock(&trace_cmdline_lock);
2472 preempt_enable();
2473}
2474
2475static int *trace_find_tgid_ptr(int pid)
2476{
2477 /*
2478 * Pairs with the smp_store_release in set_tracer_flag() to ensure that
2479 * if we observe a non-NULL tgid_map then we also observe the correct
2480 * tgid_map_max.
2481 */
2482 int *map = smp_load_acquire(&tgid_map);
2483
2484 if (unlikely(!map || pid > tgid_map_max))
2485 return NULL;
2486
2487 return &map[pid];
2488}
2489
2490int trace_find_tgid(int pid)
2491{
2492 int *ptr = trace_find_tgid_ptr(pid);
2493
2494 return ptr ? *ptr : 0;
2495}
2496
2497static int trace_save_tgid(struct task_struct *tsk)
2498{
2499 int *ptr;
2500
2501 /* treat recording of idle task as a success */
2502 if (!tsk->pid)
2503 return 1;
2504
2505 ptr = trace_find_tgid_ptr(tsk->pid);
2506 if (!ptr)
2507 return 0;
2508
2509 *ptr = tsk->tgid;
2510 return 1;
2511}
2512
2513static bool tracing_record_taskinfo_skip(int flags)
2514{
2515 if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID))))
2516 return true;
2517 if (!__this_cpu_read(trace_taskinfo_save))
2518 return true;
2519 return false;
2520}
2521
2522/**
2523 * tracing_record_taskinfo - record the task info of a task
2524 *
2525 * @task: task to record
2526 * @flags: TRACE_RECORD_CMDLINE for recording comm
2527 * TRACE_RECORD_TGID for recording tgid
2528 */
2529void tracing_record_taskinfo(struct task_struct *task, int flags)
2530{
2531 bool done;
2532
2533 if (tracing_record_taskinfo_skip(flags))
2534 return;
2535
2536 /*
2537 * Record as much task information as possible. If some fail, continue
2538 * to try to record the others.
2539 */
2540 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task);
2541 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task);
2542
2543 /* If recording any information failed, retry again soon. */
2544 if (!done)
2545 return;
2546
2547 __this_cpu_write(trace_taskinfo_save, false);
2548}
2549
2550/**
2551 * tracing_record_taskinfo_sched_switch - record task info for sched_switch
2552 *
2553 * @prev: previous task during sched_switch
2554 * @next: next task during sched_switch
2555 * @flags: TRACE_RECORD_CMDLINE for recording comm
2556 * TRACE_RECORD_TGID for recording tgid
2557 */
2558void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
2559 struct task_struct *next, int flags)
2560{
2561 bool done;
2562
2563 if (tracing_record_taskinfo_skip(flags))
2564 return;
2565
2566 /*
2567 * Record as much task information as possible. If some fail, continue
2568 * to try to record the others.
2569 */
2570 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev);
2571 done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next);
2572 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev);
2573 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next);
2574
2575 /* If recording any information failed, retry again soon. */
2576 if (!done)
2577 return;
2578
2579 __this_cpu_write(trace_taskinfo_save, false);
2580}
2581
2582/* Helpers to record a specific task information */
2583void tracing_record_cmdline(struct task_struct *task)
2584{
2585 tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE);
2586}
2587
2588void tracing_record_tgid(struct task_struct *task)
2589{
2590 tracing_record_taskinfo(task, TRACE_RECORD_TGID);
2591}
2592
2593/*
2594 * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
2595 * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
2596 * simplifies those functions and keeps them in sync.
2597 */
2598enum print_line_t trace_handle_return(struct trace_seq *s)
2599{
2600 return trace_seq_has_overflowed(s) ?
2601 TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
2602}
2603EXPORT_SYMBOL_GPL(trace_handle_return);
2604
2605unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
2606{
2607 unsigned int trace_flags = irqs_status;
2608 unsigned int pc;
2609
2610 pc = preempt_count();
2611
2612 if (pc & NMI_MASK)
2613 trace_flags |= TRACE_FLAG_NMI;
2614 if (pc & HARDIRQ_MASK)
2615 trace_flags |= TRACE_FLAG_HARDIRQ;
2616 if (in_serving_softirq())
2617 trace_flags |= TRACE_FLAG_SOFTIRQ;
2618
2619 if (tif_need_resched())
2620 trace_flags |= TRACE_FLAG_NEED_RESCHED;
2621 if (test_preempt_need_resched())
2622 trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
2623 return (trace_flags << 16) | (pc & 0xff);
2624}
2625
2626struct ring_buffer_event *
2627trace_buffer_lock_reserve(struct trace_buffer *buffer,
2628 int type,
2629 unsigned long len,
2630 unsigned int trace_ctx)
2631{
2632 return __trace_buffer_lock_reserve(buffer, type, len, trace_ctx);
2633}
2634
2635DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
2636DEFINE_PER_CPU(int, trace_buffered_event_cnt);
2637static int trace_buffered_event_ref;
2638
2639/**
2640 * trace_buffered_event_enable - enable buffering events
2641 *
2642 * When events are being filtered, it is quicker to use a temporary
2643 * buffer to write the event data into if there's a likely chance
2644 * that it will not be committed. The discard of the ring buffer
2645 * is not as fast as committing, and is much slower than copying
2646 * a commit.
2647 *
2648 * When an event is to be filtered, allocate per cpu buffers to
2649 * write the event data into, and if the event is filtered and discarded
2650 * it is simply dropped, otherwise, the entire data is to be committed
2651 * in one shot.
2652 */
2653void trace_buffered_event_enable(void)
2654{
2655 struct ring_buffer_event *event;
2656 struct page *page;
2657 int cpu;
2658
2659 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2660
2661 if (trace_buffered_event_ref++)
2662 return;
2663
2664 for_each_tracing_cpu(cpu) {
2665 page = alloc_pages_node(cpu_to_node(cpu),
2666 GFP_KERNEL | __GFP_NORETRY, 0);
2667 if (!page)
2668 goto failed;
2669
2670 event = page_address(page);
2671 memset(event, 0, sizeof(*event));
2672
2673 per_cpu(trace_buffered_event, cpu) = event;
2674
2675 preempt_disable();
2676 if (cpu == smp_processor_id() &&
2677 __this_cpu_read(trace_buffered_event) !=
2678 per_cpu(trace_buffered_event, cpu))
2679 WARN_ON_ONCE(1);
2680 preempt_enable();
2681 }
2682
2683 return;
2684 failed:
2685 trace_buffered_event_disable();
2686}
2687
2688static void enable_trace_buffered_event(void *data)
2689{
2690 /* Probably not needed, but do it anyway */
2691 smp_rmb();
2692 this_cpu_dec(trace_buffered_event_cnt);
2693}
2694
2695static void disable_trace_buffered_event(void *data)
2696{
2697 this_cpu_inc(trace_buffered_event_cnt);
2698}
2699
2700/**
2701 * trace_buffered_event_disable - disable buffering events
2702 *
2703 * When a filter is removed, it is faster to not use the buffered
2704 * events, and to commit directly into the ring buffer. Free up
2705 * the temp buffers when there are no more users. This requires
2706 * special synchronization with current events.
2707 */
2708void trace_buffered_event_disable(void)
2709{
2710 int cpu;
2711
2712 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2713
2714 if (WARN_ON_ONCE(!trace_buffered_event_ref))
2715 return;
2716
2717 if (--trace_buffered_event_ref)
2718 return;
2719
2720 preempt_disable();
2721 /* For each CPU, set the buffer as used. */
2722 smp_call_function_many(tracing_buffer_mask,
2723 disable_trace_buffered_event, NULL, 1);
2724 preempt_enable();
2725
2726 /* Wait for all current users to finish */
2727 synchronize_rcu();
2728
2729 for_each_tracing_cpu(cpu) {
2730 free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
2731 per_cpu(trace_buffered_event, cpu) = NULL;
2732 }
2733 /*
2734 * Make sure trace_buffered_event is NULL before clearing
2735 * trace_buffered_event_cnt.
2736 */
2737 smp_wmb();
2738
2739 preempt_disable();
2740 /* Do the work on each cpu */
2741 smp_call_function_many(tracing_buffer_mask,
2742 enable_trace_buffered_event, NULL, 1);
2743 preempt_enable();
2744}
2745
2746static struct trace_buffer *temp_buffer;
2747
2748struct ring_buffer_event *
2749trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
2750 struct trace_event_file *trace_file,
2751 int type, unsigned long len,
2752 unsigned int trace_ctx)
2753{
2754 struct ring_buffer_event *entry;
2755 struct trace_array *tr = trace_file->tr;
2756 int val;
2757
2758 *current_rb = tr->array_buffer.buffer;
2759
2760 if (!tr->no_filter_buffering_ref &&
2761 (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
2762 (entry = this_cpu_read(trace_buffered_event))) {
2763 /*
2764 * Filtering is on, so try to use the per cpu buffer first.
2765 * This buffer will simulate a ring_buffer_event,
2766 * where the type_len is zero and the array[0] will
2767 * hold the full length.
2768 * (see include/linux/ring-buffer.h for details on
2769 * how the ring_buffer_event is structured).
2770 *
2771 * Using a temp buffer during filtering and copying it
2772 * on a matched filter is quicker than writing directly
2773 * into the ring buffer and then discarding it when
2774 * it doesn't match. That is because the discard
2775 * requires several atomic operations to get right.
2776 * Copying on match and doing nothing on a failed match
2777 * is still quicker than no copy on match, but having
2778 * to discard out of the ring buffer on a failed match.
2779 */
2780 int max_len = PAGE_SIZE - struct_size(entry, array, 1);
2781
2782 val = this_cpu_inc_return(trace_buffered_event_cnt);
2783
2784 /*
2785 * Preemption is disabled, but interrupts and NMIs
2786 * can still come in now. If that happens after
2787 * the above increment, then it will have to go
2788 * back to the old method of allocating the event
2789 * on the ring buffer, and if the filter fails, it
2790 * will have to call ring_buffer_discard_commit()
2791 * to remove it.
2792 *
2793 * Need to also check the unlikely case that the
2794 * length is bigger than the temp buffer size.
2795 * If that happens, then the reserve is pretty much
2796 * guaranteed to fail, as the ring buffer currently
2797 * only allows events less than a page. But that may
2798 * change in the future, so let the ring buffer reserve
2799 * handle the failure in that case.
2800 */
2801 if (val == 1 && likely(len <= max_len)) {
2802 trace_event_setup(entry, type, trace_ctx);
2803 entry->array[0] = len;
2804 return entry;
2805 }
2806 this_cpu_dec(trace_buffered_event_cnt);
2807 }
2808
2809 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2810 trace_ctx);
2811 /*
2812 * If tracing is off, but we have triggers enabled
2813 * we still need to look at the event data. Use the temp_buffer
2814 * to store the trace event for the trigger to use. It's recursive
2815 * safe and will not be recorded anywhere.
2816 */
2817 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
2818 *current_rb = temp_buffer;
2819 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2820 trace_ctx);
2821 }
2822 return entry;
2823}
2824EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
2825
2826static DEFINE_SPINLOCK(tracepoint_iter_lock);
2827static DEFINE_MUTEX(tracepoint_printk_mutex);
2828
2829static void output_printk(struct trace_event_buffer *fbuffer)
2830{
2831 struct trace_event_call *event_call;
2832 struct trace_event_file *file;
2833 struct trace_event *event;
2834 unsigned long flags;
2835 struct trace_iterator *iter = tracepoint_print_iter;
2836
2837 /* We should never get here if iter is NULL */
2838 if (WARN_ON_ONCE(!iter))
2839 return;
2840
2841 event_call = fbuffer->trace_file->event_call;
2842 if (!event_call || !event_call->event.funcs ||
2843 !event_call->event.funcs->trace)
2844 return;
2845
2846 file = fbuffer->trace_file;
2847 if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) ||
2848 (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
2849 !filter_match_preds(file->filter, fbuffer->entry)))
2850 return;
2851
2852 event = &fbuffer->trace_file->event_call->event;
2853
2854 spin_lock_irqsave(&tracepoint_iter_lock, flags);
2855 trace_seq_init(&iter->seq);
2856 iter->ent = fbuffer->entry;
2857 event_call->event.funcs->trace(iter, 0, event);
2858 trace_seq_putc(&iter->seq, 0);
2859 printk("%s", iter->seq.buffer);
2860
2861 spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
2862}
2863
2864int tracepoint_printk_sysctl(struct ctl_table *table, int write,
2865 void *buffer, size_t *lenp,
2866 loff_t *ppos)
2867{
2868 int save_tracepoint_printk;
2869 int ret;
2870
2871 mutex_lock(&tracepoint_printk_mutex);
2872 save_tracepoint_printk = tracepoint_printk;
2873
2874 ret = proc_dointvec(table, write, buffer, lenp, ppos);
2875
2876 /*
2877 * This will force exiting early, as tracepoint_printk
2878 * is always zero when tracepoint_printk_iter is not allocated
2879 */
2880 if (!tracepoint_print_iter)
2881 tracepoint_printk = 0;
2882
2883 if (save_tracepoint_printk == tracepoint_printk)
2884 goto out;
2885
2886 if (tracepoint_printk)
2887 static_key_enable(&tracepoint_printk_key.key);
2888 else
2889 static_key_disable(&tracepoint_printk_key.key);
2890
2891 out:
2892 mutex_unlock(&tracepoint_printk_mutex);
2893
2894 return ret;
2895}
2896
2897void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
2898{
2899 enum event_trigger_type tt = ETT_NONE;
2900 struct trace_event_file *file = fbuffer->trace_file;
2901
2902 if (__event_trigger_test_discard(file, fbuffer->buffer, fbuffer->event,
2903 fbuffer->entry, &tt))
2904 goto discard;
2905
2906 if (static_key_false(&tracepoint_printk_key.key))
2907 output_printk(fbuffer);
2908
2909 if (static_branch_unlikely(&trace_event_exports_enabled))
2910 ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT);
2911
2912 trace_buffer_unlock_commit_regs(file->tr, fbuffer->buffer,
2913 fbuffer->event, fbuffer->trace_ctx, fbuffer->regs);
2914
2915discard:
2916 if (tt)
2917 event_triggers_post_call(file, tt);
2918
2919}
2920EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
2921
2922/*
2923 * Skip 3:
2924 *
2925 * trace_buffer_unlock_commit_regs()
2926 * trace_event_buffer_commit()
2927 * trace_event_raw_event_xxx()
2928 */
2929# define STACK_SKIP 3
2930
2931void trace_buffer_unlock_commit_regs(struct trace_array *tr,
2932 struct trace_buffer *buffer,
2933 struct ring_buffer_event *event,
2934 unsigned int trace_ctx,
2935 struct pt_regs *regs)
2936{
2937 __buffer_unlock_commit(buffer, event);
2938
2939 /*
2940 * If regs is not set, then skip the necessary functions.
2941 * Note, we can still get here via blktrace, wakeup tracer
2942 * and mmiotrace, but that's ok if they lose a function or
2943 * two. They are not that meaningful.
2944 */
2945 ftrace_trace_stack(tr, buffer, trace_ctx, regs ? 0 : STACK_SKIP, regs);
2946 ftrace_trace_userstack(tr, buffer, trace_ctx);
2947}
2948
2949/*
2950 * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
2951 */
2952void
2953trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
2954 struct ring_buffer_event *event)
2955{
2956 __buffer_unlock_commit(buffer, event);
2957}
2958
2959void
2960trace_function(struct trace_array *tr, unsigned long ip, unsigned long
2961 parent_ip, unsigned int trace_ctx)
2962{
2963 struct trace_event_call *call = &event_function;
2964 struct trace_buffer *buffer = tr->array_buffer.buffer;
2965 struct ring_buffer_event *event;
2966 struct ftrace_entry *entry;
2967
2968 event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
2969 trace_ctx);
2970 if (!event)
2971 return;
2972 entry = ring_buffer_event_data(event);
2973 entry->ip = ip;
2974 entry->parent_ip = parent_ip;
2975
2976 if (!call_filter_check_discard(call, entry, buffer, event)) {
2977 if (static_branch_unlikely(&trace_function_exports_enabled))
2978 ftrace_exports(event, TRACE_EXPORT_FUNCTION);
2979 __buffer_unlock_commit(buffer, event);
2980 }
2981}
2982
2983#ifdef CONFIG_STACKTRACE
2984
2985/* Allow 4 levels of nesting: normal, softirq, irq, NMI */
2986#define FTRACE_KSTACK_NESTING 4
2987
2988#define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING)
2989
2990struct ftrace_stack {
2991 unsigned long calls[FTRACE_KSTACK_ENTRIES];
2992};
2993
2994
2995struct ftrace_stacks {
2996 struct ftrace_stack stacks[FTRACE_KSTACK_NESTING];
2997};
2998
2999static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
3000static DEFINE_PER_CPU(int, ftrace_stack_reserve);
3001
3002static void __ftrace_trace_stack(struct trace_buffer *buffer,
3003 unsigned int trace_ctx,
3004 int skip, struct pt_regs *regs)
3005{
3006 struct trace_event_call *call = &event_kernel_stack;
3007 struct ring_buffer_event *event;
3008 unsigned int size, nr_entries;
3009 struct ftrace_stack *fstack;
3010 struct stack_entry *entry;
3011 int stackidx;
3012
3013 /*
3014 * Add one, for this function and the call to save_stack_trace()
3015 * If regs is set, then these functions will not be in the way.
3016 */
3017#ifndef CONFIG_UNWINDER_ORC
3018 if (!regs)
3019 skip++;
3020#endif
3021
3022 preempt_disable_notrace();
3023
3024 stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
3025
3026 /* This should never happen. If it does, yell once and skip */
3027 if (WARN_ON_ONCE(stackidx >= FTRACE_KSTACK_NESTING))
3028 goto out;
3029
3030 /*
3031 * The above __this_cpu_inc_return() is 'atomic' cpu local. An
3032 * interrupt will either see the value pre increment or post
3033 * increment. If the interrupt happens pre increment it will have
3034 * restored the counter when it returns. We just need a barrier to
3035 * keep gcc from moving things around.
3036 */
3037 barrier();
3038
3039 fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx;
3040 size = ARRAY_SIZE(fstack->calls);
3041
3042 if (regs) {
3043 nr_entries = stack_trace_save_regs(regs, fstack->calls,
3044 size, skip);
3045 } else {
3046 nr_entries = stack_trace_save(fstack->calls, size, skip);
3047 }
3048
3049 size = nr_entries * sizeof(unsigned long);
3050 event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
3051 (sizeof(*entry) - sizeof(entry->caller)) + size,
3052 trace_ctx);
3053 if (!event)
3054 goto out;
3055 entry = ring_buffer_event_data(event);
3056
3057 memcpy(&entry->caller, fstack->calls, size);
3058 entry->size = nr_entries;
3059
3060 if (!call_filter_check_discard(call, entry, buffer, event))
3061 __buffer_unlock_commit(buffer, event);
3062
3063 out:
3064 /* Again, don't let gcc optimize things here */
3065 barrier();
3066 __this_cpu_dec(ftrace_stack_reserve);
3067 preempt_enable_notrace();
3068
3069}
3070
3071static inline void ftrace_trace_stack(struct trace_array *tr,
3072 struct trace_buffer *buffer,
3073 unsigned int trace_ctx,
3074 int skip, struct pt_regs *regs)
3075{
3076 if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
3077 return;
3078
3079 __ftrace_trace_stack(buffer, trace_ctx, skip, regs);
3080}
3081
3082void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
3083 int skip)
3084{
3085 struct trace_buffer *buffer = tr->array_buffer.buffer;
3086
3087 if (rcu_is_watching()) {
3088 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
3089 return;
3090 }
3091
3092 /*
3093 * When an NMI triggers, RCU is enabled via rcu_nmi_enter(),
3094 * but if the above rcu_is_watching() failed, then the NMI
3095 * triggered someplace critical, and rcu_irq_enter() should
3096 * not be called from NMI.
3097 */
3098 if (unlikely(in_nmi()))
3099 return;
3100
3101 rcu_irq_enter_irqson();
3102 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
3103 rcu_irq_exit_irqson();
3104}
3105
3106/**
3107 * trace_dump_stack - record a stack back trace in the trace buffer
3108 * @skip: Number of functions to skip (helper handlers)
3109 */
3110void trace_dump_stack(int skip)
3111{
3112 if (tracing_disabled || tracing_selftest_running)
3113 return;
3114
3115#ifndef CONFIG_UNWINDER_ORC
3116 /* Skip 1 to skip this function. */
3117 skip++;
3118#endif
3119 __ftrace_trace_stack(global_trace.array_buffer.buffer,
3120 tracing_gen_ctx(), skip, NULL);
3121}
3122EXPORT_SYMBOL_GPL(trace_dump_stack);
3123
3124#ifdef CONFIG_USER_STACKTRACE_SUPPORT
3125static DEFINE_PER_CPU(int, user_stack_count);
3126
3127static void
3128ftrace_trace_userstack(struct trace_array *tr,
3129 struct trace_buffer *buffer, unsigned int trace_ctx)
3130{
3131 struct trace_event_call *call = &event_user_stack;
3132 struct ring_buffer_event *event;
3133 struct userstack_entry *entry;
3134
3135 if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE))
3136 return;
3137
3138 /*
3139 * NMIs can not handle page faults, even with fix ups.
3140 * The save user stack can (and often does) fault.
3141 */
3142 if (unlikely(in_nmi()))
3143 return;
3144
3145 /*
3146 * prevent recursion, since the user stack tracing may
3147 * trigger other kernel events.
3148 */
3149 preempt_disable();
3150 if (__this_cpu_read(user_stack_count))
3151 goto out;
3152
3153 __this_cpu_inc(user_stack_count);
3154
3155 event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
3156 sizeof(*entry), trace_ctx);
3157 if (!event)
3158 goto out_drop_count;
3159 entry = ring_buffer_event_data(event);
3160
3161 entry->tgid = current->tgid;
3162 memset(&entry->caller, 0, sizeof(entry->caller));
3163
3164 stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES);
3165 if (!call_filter_check_discard(call, entry, buffer, event))
3166 __buffer_unlock_commit(buffer, event);
3167
3168 out_drop_count:
3169 __this_cpu_dec(user_stack_count);
3170 out:
3171 preempt_enable();
3172}
3173#else /* CONFIG_USER_STACKTRACE_SUPPORT */
3174static void ftrace_trace_userstack(struct trace_array *tr,
3175 struct trace_buffer *buffer,
3176 unsigned int trace_ctx)
3177{
3178}
3179#endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
3180
3181#endif /* CONFIG_STACKTRACE */
3182
3183static inline void
3184func_repeats_set_delta_ts(struct func_repeats_entry *entry,
3185 unsigned long long delta)
3186{
3187 entry->bottom_delta_ts = delta & U32_MAX;
3188 entry->top_delta_ts = (delta >> 32);
3189}
3190
3191void trace_last_func_repeats(struct trace_array *tr,
3192 struct trace_func_repeats *last_info,
3193 unsigned int trace_ctx)
3194{
3195 struct trace_buffer *buffer = tr->array_buffer.buffer;
3196 struct func_repeats_entry *entry;
3197 struct ring_buffer_event *event;
3198 u64 delta;
3199
3200 event = __trace_buffer_lock_reserve(buffer, TRACE_FUNC_REPEATS,
3201 sizeof(*entry), trace_ctx);
3202 if (!event)
3203 return;
3204
3205 delta = ring_buffer_event_time_stamp(buffer, event) -
3206 last_info->ts_last_call;
3207
3208 entry = ring_buffer_event_data(event);
3209 entry->ip = last_info->ip;
3210 entry->parent_ip = last_info->parent_ip;
3211 entry->count = last_info->count;
3212 func_repeats_set_delta_ts(entry, delta);
3213
3214 __buffer_unlock_commit(buffer, event);
3215}
3216
3217/* created for use with alloc_percpu */
3218struct trace_buffer_struct {
3219 int nesting;
3220 char buffer[4][TRACE_BUF_SIZE];
3221};
3222
3223static struct trace_buffer_struct *trace_percpu_buffer;
3224
3225/*
3226 * This allows for lockless recording. If we're nested too deeply, then
3227 * this returns NULL.
3228 */
3229static char *get_trace_buf(void)
3230{
3231 struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
3232
3233 if (!buffer || buffer->nesting >= 4)
3234 return NULL;
3235
3236 buffer->nesting++;
3237
3238 /* Interrupts must see nesting incremented before we use the buffer */
3239 barrier();
3240 return &buffer->buffer[buffer->nesting - 1][0];
3241}
3242
3243static void put_trace_buf(void)
3244{
3245 /* Don't let the decrement of nesting leak before this */
3246 barrier();
3247 this_cpu_dec(trace_percpu_buffer->nesting);
3248}
3249
3250static int alloc_percpu_trace_buffer(void)
3251{
3252 struct trace_buffer_struct *buffers;
3253
3254 if (trace_percpu_buffer)
3255 return 0;
3256
3257 buffers = alloc_percpu(struct trace_buffer_struct);
3258 if (MEM_FAIL(!buffers, "Could not allocate percpu trace_printk buffer"))
3259 return -ENOMEM;
3260
3261 trace_percpu_buffer = buffers;
3262 return 0;
3263}
3264
3265static int buffers_allocated;
3266
3267void trace_printk_init_buffers(void)
3268{
3269 if (buffers_allocated)
3270 return;
3271
3272 if (alloc_percpu_trace_buffer())
3273 return;
3274
3275 /* trace_printk() is for debug use only. Don't use it in production. */
3276
3277 pr_warn("\n");
3278 pr_warn("**********************************************************\n");
3279 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3280 pr_warn("** **\n");
3281 pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
3282 pr_warn("** **\n");
3283 pr_warn("** This means that this is a DEBUG kernel and it is **\n");
3284 pr_warn("** unsafe for production use. **\n");
3285 pr_warn("** **\n");
3286 pr_warn("** If you see this message and you are not debugging **\n");
3287 pr_warn("** the kernel, report this immediately to your vendor! **\n");
3288 pr_warn("** **\n");
3289 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3290 pr_warn("**********************************************************\n");
3291
3292 /* Expand the buffers to set size */
3293 tracing_update_buffers();
3294
3295 buffers_allocated = 1;
3296
3297 /*
3298 * trace_printk_init_buffers() can be called by modules.
3299 * If that happens, then we need to start cmdline recording
3300 * directly here. If the global_trace.buffer is already
3301 * allocated here, then this was called by module code.
3302 */
3303 if (global_trace.array_buffer.buffer)
3304 tracing_start_cmdline_record();
3305}
3306EXPORT_SYMBOL_GPL(trace_printk_init_buffers);
3307
3308void trace_printk_start_comm(void)
3309{
3310 /* Start tracing comms if trace printk is set */
3311 if (!buffers_allocated)
3312 return;
3313 tracing_start_cmdline_record();
3314}
3315
3316static void trace_printk_start_stop_comm(int enabled)
3317{
3318 if (!buffers_allocated)
3319 return;
3320
3321 if (enabled)
3322 tracing_start_cmdline_record();
3323 else
3324 tracing_stop_cmdline_record();
3325}
3326
3327/**
3328 * trace_vbprintk - write binary msg to tracing buffer
3329 * @ip: The address of the caller
3330 * @fmt: The string format to write to the buffer
3331 * @args: Arguments for @fmt
3332 */
3333int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
3334{
3335 struct trace_event_call *call = &event_bprint;
3336 struct ring_buffer_event *event;
3337 struct trace_buffer *buffer;
3338 struct trace_array *tr = &global_trace;
3339 struct bprint_entry *entry;
3340 unsigned int trace_ctx;
3341 char *tbuffer;
3342 int len = 0, size;
3343
3344 if (unlikely(tracing_selftest_running || tracing_disabled))
3345 return 0;
3346
3347 /* Don't pollute graph traces with trace_vprintk internals */
3348 pause_graph_tracing();
3349
3350 trace_ctx = tracing_gen_ctx();
3351 preempt_disable_notrace();
3352
3353 tbuffer = get_trace_buf();
3354 if (!tbuffer) {
3355 len = 0;
3356 goto out_nobuffer;
3357 }
3358
3359 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
3360
3361 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
3362 goto out_put;
3363
3364 size = sizeof(*entry) + sizeof(u32) * len;
3365 buffer = tr->array_buffer.buffer;
3366 ring_buffer_nest_start(buffer);
3367 event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
3368 trace_ctx);
3369 if (!event)
3370 goto out;
3371 entry = ring_buffer_event_data(event);
3372 entry->ip = ip;
3373 entry->fmt = fmt;
3374
3375 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
3376 if (!call_filter_check_discard(call, entry, buffer, event)) {
3377 __buffer_unlock_commit(buffer, event);
3378 ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL);
3379 }
3380
3381out:
3382 ring_buffer_nest_end(buffer);
3383out_put:
3384 put_trace_buf();
3385
3386out_nobuffer:
3387 preempt_enable_notrace();
3388 unpause_graph_tracing();
3389
3390 return len;
3391}
3392EXPORT_SYMBOL_GPL(trace_vbprintk);
3393
3394__printf(3, 0)
3395static int
3396__trace_array_vprintk(struct trace_buffer *buffer,
3397 unsigned long ip, const char *fmt, va_list args)
3398{
3399 struct trace_event_call *call = &event_print;
3400 struct ring_buffer_event *event;
3401 int len = 0, size;
3402 struct print_entry *entry;
3403 unsigned int trace_ctx;
3404 char *tbuffer;
3405
3406 if (tracing_disabled || tracing_selftest_running)
3407 return 0;
3408
3409 /* Don't pollute graph traces with trace_vprintk internals */
3410 pause_graph_tracing();
3411
3412 trace_ctx = tracing_gen_ctx();
3413 preempt_disable_notrace();
3414
3415
3416 tbuffer = get_trace_buf();
3417 if (!tbuffer) {
3418 len = 0;
3419 goto out_nobuffer;
3420 }
3421
3422 len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
3423
3424 size = sizeof(*entry) + len + 1;
3425 ring_buffer_nest_start(buffer);
3426 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3427 trace_ctx);
3428 if (!event)
3429 goto out;
3430 entry = ring_buffer_event_data(event);
3431 entry->ip = ip;
3432
3433 memcpy(&entry->buf, tbuffer, len + 1);
3434 if (!call_filter_check_discard(call, entry, buffer, event)) {
3435 __buffer_unlock_commit(buffer, event);
3436 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 6, NULL);
3437 }
3438
3439out:
3440 ring_buffer_nest_end(buffer);
3441 put_trace_buf();
3442
3443out_nobuffer:
3444 preempt_enable_notrace();
3445 unpause_graph_tracing();
3446
3447 return len;
3448}
3449
3450__printf(3, 0)
3451int trace_array_vprintk(struct trace_array *tr,
3452 unsigned long ip, const char *fmt, va_list args)
3453{
3454 return __trace_array_vprintk(tr->array_buffer.buffer, ip, fmt, args);
3455}
3456
3457/**
3458 * trace_array_printk - Print a message to a specific instance
3459 * @tr: The instance trace_array descriptor
3460 * @ip: The instruction pointer that this is called from.
3461 * @fmt: The format to print (printf format)
3462 *
3463 * If a subsystem sets up its own instance, they have the right to
3464 * printk strings into their tracing instance buffer using this
3465 * function. Note, this function will not write into the top level
3466 * buffer (use trace_printk() for that), as writing into the top level
3467 * buffer should only have events that can be individually disabled.
3468 * trace_printk() is only used for debugging a kernel, and should not
3469 * be ever incorporated in normal use.
3470 *
3471 * trace_array_printk() can be used, as it will not add noise to the
3472 * top level tracing buffer.
3473 *
3474 * Note, trace_array_init_printk() must be called on @tr before this
3475 * can be used.
3476 */
3477__printf(3, 0)
3478int trace_array_printk(struct trace_array *tr,
3479 unsigned long ip, const char *fmt, ...)
3480{
3481 int ret;
3482 va_list ap;
3483
3484 if (!tr)
3485 return -ENOENT;
3486
3487 /* This is only allowed for created instances */
3488 if (tr == &global_trace)
3489 return 0;
3490
3491 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
3492 return 0;
3493
3494 va_start(ap, fmt);
3495 ret = trace_array_vprintk(tr, ip, fmt, ap);
3496 va_end(ap);
3497 return ret;
3498}
3499EXPORT_SYMBOL_GPL(trace_array_printk);
3500
3501/**
3502 * trace_array_init_printk - Initialize buffers for trace_array_printk()
3503 * @tr: The trace array to initialize the buffers for
3504 *
3505 * As trace_array_printk() only writes into instances, they are OK to
3506 * have in the kernel (unlike trace_printk()). This needs to be called
3507 * before trace_array_printk() can be used on a trace_array.
3508 */
3509int trace_array_init_printk(struct trace_array *tr)
3510{
3511 if (!tr)
3512 return -ENOENT;
3513
3514 /* This is only allowed for created instances */
3515 if (tr == &global_trace)
3516 return -EINVAL;
3517
3518 return alloc_percpu_trace_buffer();
3519}
3520EXPORT_SYMBOL_GPL(trace_array_init_printk);
3521
3522__printf(3, 4)
3523int trace_array_printk_buf(struct trace_buffer *buffer,
3524 unsigned long ip, const char *fmt, ...)
3525{
3526 int ret;
3527 va_list ap;
3528
3529 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
3530 return 0;
3531
3532 va_start(ap, fmt);
3533 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
3534 va_end(ap);
3535 return ret;
3536}
3537
3538__printf(2, 0)
3539int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3540{
3541 return trace_array_vprintk(&global_trace, ip, fmt, args);
3542}
3543EXPORT_SYMBOL_GPL(trace_vprintk);
3544
3545static void trace_iterator_increment(struct trace_iterator *iter)
3546{
3547 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
3548
3549 iter->idx++;
3550 if (buf_iter)
3551 ring_buffer_iter_advance(buf_iter);
3552}
3553
3554static struct trace_entry *
3555peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
3556 unsigned long *lost_events)
3557{
3558 struct ring_buffer_event *event;
3559 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
3560
3561 if (buf_iter) {
3562 event = ring_buffer_iter_peek(buf_iter, ts);
3563 if (lost_events)
3564 *lost_events = ring_buffer_iter_dropped(buf_iter) ?
3565 (unsigned long)-1 : 0;
3566 } else {
3567 event = ring_buffer_peek(iter->array_buffer->buffer, cpu, ts,
3568 lost_events);
3569 }
3570
3571 if (event) {
3572 iter->ent_size = ring_buffer_event_length(event);
3573 return ring_buffer_event_data(event);
3574 }
3575 iter->ent_size = 0;
3576 return NULL;
3577}
3578
3579static struct trace_entry *
3580__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
3581 unsigned long *missing_events, u64 *ent_ts)
3582{
3583 struct trace_buffer *buffer = iter->array_buffer->buffer;
3584 struct trace_entry *ent, *next = NULL;
3585 unsigned long lost_events = 0, next_lost = 0;
3586 int cpu_file = iter->cpu_file;
3587 u64 next_ts = 0, ts;
3588 int next_cpu = -1;
3589 int next_size = 0;
3590 int cpu;
3591
3592 /*
3593 * If we are in a per_cpu trace file, don't bother by iterating over
3594 * all cpu and peek directly.
3595 */
3596 if (cpu_file > RING_BUFFER_ALL_CPUS) {
3597 if (ring_buffer_empty_cpu(buffer, cpu_file))
3598 return NULL;
3599 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
3600 if (ent_cpu)
3601 *ent_cpu = cpu_file;
3602
3603 return ent;
3604 }
3605
3606 for_each_tracing_cpu(cpu) {
3607
3608 if (ring_buffer_empty_cpu(buffer, cpu))
3609 continue;
3610
3611 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
3612
3613 /*
3614 * Pick the entry with the smallest timestamp:
3615 */
3616 if (ent && (!next || ts < next_ts)) {
3617 next = ent;
3618 next_cpu = cpu;
3619 next_ts = ts;
3620 next_lost = lost_events;
3621 next_size = iter->ent_size;
3622 }
3623 }
3624
3625 iter->ent_size = next_size;
3626
3627 if (ent_cpu)
3628 *ent_cpu = next_cpu;
3629
3630 if (ent_ts)
3631 *ent_ts = next_ts;
3632
3633 if (missing_events)
3634 *missing_events = next_lost;
3635
3636 return next;
3637}
3638
3639#define STATIC_FMT_BUF_SIZE 128
3640static char static_fmt_buf[STATIC_FMT_BUF_SIZE];
3641
3642static char *trace_iter_expand_format(struct trace_iterator *iter)
3643{
3644 char *tmp;
3645
3646 /*
3647 * iter->tr is NULL when used with tp_printk, which makes
3648 * this get called where it is not safe to call krealloc().
3649 */
3650 if (!iter->tr || iter->fmt == static_fmt_buf)
3651 return NULL;
3652
3653 tmp = krealloc(iter->fmt, iter->fmt_size + STATIC_FMT_BUF_SIZE,
3654 GFP_KERNEL);
3655 if (tmp) {
3656 iter->fmt_size += STATIC_FMT_BUF_SIZE;
3657 iter->fmt = tmp;
3658 }
3659
3660 return tmp;
3661}
3662
3663/* Returns true if the string is safe to dereference from an event */
3664static bool trace_safe_str(struct trace_iterator *iter, const char *str)
3665{
3666 unsigned long addr = (unsigned long)str;
3667 struct trace_event *trace_event;
3668 struct trace_event_call *event;
3669
3670 /* OK if part of the event data */
3671 if ((addr >= (unsigned long)iter->ent) &&
3672 (addr < (unsigned long)iter->ent + iter->ent_size))
3673 return true;
3674
3675 /* OK if part of the temp seq buffer */
3676 if ((addr >= (unsigned long)iter->tmp_seq.buffer) &&
3677 (addr < (unsigned long)iter->tmp_seq.buffer + PAGE_SIZE))
3678 return true;
3679
3680 /* Core rodata can not be freed */
3681 if (is_kernel_rodata(addr))
3682 return true;
3683
3684 if (trace_is_tracepoint_string(str))
3685 return true;
3686
3687 /*
3688 * Now this could be a module event, referencing core module
3689 * data, which is OK.
3690 */
3691 if (!iter->ent)
3692 return false;
3693
3694 trace_event = ftrace_find_event(iter->ent->type);
3695 if (!trace_event)
3696 return false;
3697
3698 event = container_of(trace_event, struct trace_event_call, event);
3699 if (!event->mod)
3700 return false;
3701
3702 /* Would rather have rodata, but this will suffice */
3703 if (within_module_core(addr, event->mod))
3704 return true;
3705
3706 return false;
3707}
3708
3709static const char *show_buffer(struct trace_seq *s)
3710{
3711 struct seq_buf *seq = &s->seq;
3712
3713 seq_buf_terminate(seq);
3714
3715 return seq->buffer;
3716}
3717
3718static DEFINE_STATIC_KEY_FALSE(trace_no_verify);
3719
3720static int test_can_verify_check(const char *fmt, ...)
3721{
3722 char buf[16];
3723 va_list ap;
3724 int ret;
3725
3726 /*
3727 * The verifier is dependent on vsnprintf() modifies the va_list
3728 * passed to it, where it is sent as a reference. Some architectures
3729 * (like x86_32) passes it by value, which means that vsnprintf()
3730 * does not modify the va_list passed to it, and the verifier
3731 * would then need to be able to understand all the values that
3732 * vsnprintf can use. If it is passed by value, then the verifier
3733 * is disabled.
3734 */
3735 va_start(ap, fmt);
3736 vsnprintf(buf, 16, "%d", ap);
3737 ret = va_arg(ap, int);
3738 va_end(ap);
3739
3740 return ret;
3741}
3742
3743static void test_can_verify(void)
3744{
3745 if (!test_can_verify_check("%d %d", 0, 1)) {
3746 pr_info("trace event string verifier disabled\n");
3747 static_branch_inc(&trace_no_verify);
3748 }
3749}
3750
3751/**
3752 * trace_check_vprintf - Check dereferenced strings while writing to the seq buffer
3753 * @iter: The iterator that holds the seq buffer and the event being printed
3754 * @fmt: The format used to print the event
3755 * @ap: The va_list holding the data to print from @fmt.
3756 *
3757 * This writes the data into the @iter->seq buffer using the data from
3758 * @fmt and @ap. If the format has a %s, then the source of the string
3759 * is examined to make sure it is safe to print, otherwise it will
3760 * warn and print "[UNSAFE MEMORY]" in place of the dereferenced string
3761 * pointer.
3762 */
3763void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
3764 va_list ap)
3765{
3766 const char *p = fmt;
3767 const char *str;
3768 int i, j;
3769
3770 if (WARN_ON_ONCE(!fmt))
3771 return;
3772
3773 if (static_branch_unlikely(&trace_no_verify))
3774 goto print;
3775
3776 /* Don't bother checking when doing a ftrace_dump() */
3777 if (iter->fmt == static_fmt_buf)
3778 goto print;
3779
3780 while (*p) {
3781 bool star = false;
3782 int len = 0;
3783
3784 j = 0;
3785
3786 /* We only care about %s and variants */
3787 for (i = 0; p[i]; i++) {
3788 if (i + 1 >= iter->fmt_size) {
3789 /*
3790 * If we can't expand the copy buffer,
3791 * just print it.
3792 */
3793 if (!trace_iter_expand_format(iter))
3794 goto print;
3795 }
3796
3797 if (p[i] == '\\' && p[i+1]) {
3798 i++;
3799 continue;
3800 }
3801 if (p[i] == '%') {
3802 /* Need to test cases like %08.*s */
3803 for (j = 1; p[i+j]; j++) {
3804 if (isdigit(p[i+j]) ||
3805 p[i+j] == '.')
3806 continue;
3807 if (p[i+j] == '*') {
3808 star = true;
3809 continue;
3810 }
3811 break;
3812 }
3813 if (p[i+j] == 's')
3814 break;
3815 star = false;
3816 }
3817 j = 0;
3818 }
3819 /* If no %s found then just print normally */
3820 if (!p[i])
3821 break;
3822
3823 /* Copy up to the %s, and print that */
3824 strncpy(iter->fmt, p, i);
3825 iter->fmt[i] = '\0';
3826 trace_seq_vprintf(&iter->seq, iter->fmt, ap);
3827
3828 if (star)
3829 len = va_arg(ap, int);
3830
3831 /* The ap now points to the string data of the %s */
3832 str = va_arg(ap, const char *);
3833
3834 /*
3835 * If you hit this warning, it is likely that the
3836 * trace event in question used %s on a string that
3837 * was saved at the time of the event, but may not be
3838 * around when the trace is read. Use __string(),
3839 * __assign_str() and __get_str() helpers in the TRACE_EVENT()
3840 * instead. See samples/trace_events/trace-events-sample.h
3841 * for reference.
3842 */
3843 if (WARN_ONCE(!trace_safe_str(iter, str),
3844 "fmt: '%s' current_buffer: '%s'",
3845 fmt, show_buffer(&iter->seq))) {
3846 int ret;
3847
3848 /* Try to safely read the string */
3849 if (star) {
3850 if (len + 1 > iter->fmt_size)
3851 len = iter->fmt_size - 1;
3852 if (len < 0)
3853 len = 0;
3854 ret = copy_from_kernel_nofault(iter->fmt, str, len);
3855 iter->fmt[len] = 0;
3856 star = false;
3857 } else {
3858 ret = strncpy_from_kernel_nofault(iter->fmt, str,
3859 iter->fmt_size);
3860 }
3861 if (ret < 0)
3862 trace_seq_printf(&iter->seq, "(0x%px)", str);
3863 else
3864 trace_seq_printf(&iter->seq, "(0x%px:%s)",
3865 str, iter->fmt);
3866 str = "[UNSAFE-MEMORY]";
3867 strcpy(iter->fmt, "%s");
3868 } else {
3869 strncpy(iter->fmt, p + i, j + 1);
3870 iter->fmt[j+1] = '\0';
3871 }
3872 if (star)
3873 trace_seq_printf(&iter->seq, iter->fmt, len, str);
3874 else
3875 trace_seq_printf(&iter->seq, iter->fmt, str);
3876
3877 p += i + j + 1;
3878 }
3879 print:
3880 if (*p)
3881 trace_seq_vprintf(&iter->seq, p, ap);
3882}
3883
3884const char *trace_event_format(struct trace_iterator *iter, const char *fmt)
3885{
3886 const char *p, *new_fmt;
3887 char *q;
3888
3889 if (WARN_ON_ONCE(!fmt))
3890 return fmt;
3891
3892 if (!iter->tr || iter->tr->trace_flags & TRACE_ITER_HASH_PTR)
3893 return fmt;
3894
3895 p = fmt;
3896 new_fmt = q = iter->fmt;
3897 while (*p) {
3898 if (unlikely(q - new_fmt + 3 > iter->fmt_size)) {
3899 if (!trace_iter_expand_format(iter))
3900 return fmt;
3901
3902 q += iter->fmt - new_fmt;
3903 new_fmt = iter->fmt;
3904 }
3905
3906 *q++ = *p++;
3907
3908 /* Replace %p with %px */
3909 if (p[-1] == '%') {
3910 if (p[0] == '%') {
3911 *q++ = *p++;
3912 } else if (p[0] == 'p' && !isalnum(p[1])) {
3913 *q++ = *p++;
3914 *q++ = 'x';
3915 }
3916 }
3917 }
3918 *q = '\0';
3919
3920 return new_fmt;
3921}
3922
3923#define STATIC_TEMP_BUF_SIZE 128
3924static char static_temp_buf[STATIC_TEMP_BUF_SIZE] __aligned(4);
3925
3926/* Find the next real entry, without updating the iterator itself */
3927struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
3928 int *ent_cpu, u64 *ent_ts)
3929{
3930 /* __find_next_entry will reset ent_size */
3931 int ent_size = iter->ent_size;
3932 struct trace_entry *entry;
3933
3934 /*
3935 * If called from ftrace_dump(), then the iter->temp buffer
3936 * will be the static_temp_buf and not created from kmalloc.
3937 * If the entry size is greater than the buffer, we can
3938 * not save it. Just return NULL in that case. This is only
3939 * used to add markers when two consecutive events' time
3940 * stamps have a large delta. See trace_print_lat_context()
3941 */
3942 if (iter->temp == static_temp_buf &&
3943 STATIC_TEMP_BUF_SIZE < ent_size)
3944 return NULL;
3945
3946 /*
3947 * The __find_next_entry() may call peek_next_entry(), which may
3948 * call ring_buffer_peek() that may make the contents of iter->ent
3949 * undefined. Need to copy iter->ent now.
3950 */
3951 if (iter->ent && iter->ent != iter->temp) {
3952 if ((!iter->temp || iter->temp_size < iter->ent_size) &&
3953 !WARN_ON_ONCE(iter->temp == static_temp_buf)) {
3954 void *temp;
3955 temp = kmalloc(iter->ent_size, GFP_KERNEL);
3956 if (!temp)
3957 return NULL;
3958 kfree(iter->temp);
3959 iter->temp = temp;
3960 iter->temp_size = iter->ent_size;
3961 }
3962 memcpy(iter->temp, iter->ent, iter->ent_size);
3963 iter->ent = iter->temp;
3964 }
3965 entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);
3966 /* Put back the original ent_size */
3967 iter->ent_size = ent_size;
3968
3969 return entry;
3970}
3971
3972/* Find the next real entry, and increment the iterator to the next entry */
3973void *trace_find_next_entry_inc(struct trace_iterator *iter)
3974{
3975 iter->ent = __find_next_entry(iter, &iter->cpu,
3976 &iter->lost_events, &iter->ts);
3977
3978 if (iter->ent)
3979 trace_iterator_increment(iter);
3980
3981 return iter->ent ? iter : NULL;
3982}
3983
3984static void trace_consume(struct trace_iterator *iter)
3985{
3986 ring_buffer_consume(iter->array_buffer->buffer, iter->cpu, &iter->ts,
3987 &iter->lost_events);
3988}
3989
3990static void *s_next(struct seq_file *m, void *v, loff_t *pos)
3991{
3992 struct trace_iterator *iter = m->private;
3993 int i = (int)*pos;
3994 void *ent;
3995
3996 WARN_ON_ONCE(iter->leftover);
3997
3998 (*pos)++;
3999
4000 /* can't go backwards */
4001 if (iter->idx > i)
4002 return NULL;
4003
4004 if (iter->idx < 0)
4005 ent = trace_find_next_entry_inc(iter);
4006 else
4007 ent = iter;
4008
4009 while (ent && iter->idx < i)
4010 ent = trace_find_next_entry_inc(iter);
4011
4012 iter->pos = *pos;
4013
4014 return ent;
4015}
4016
4017void tracing_iter_reset(struct trace_iterator *iter, int cpu)
4018{
4019 struct ring_buffer_iter *buf_iter;
4020 unsigned long entries = 0;
4021 u64 ts;
4022
4023 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = 0;
4024
4025 buf_iter = trace_buffer_iter(iter, cpu);
4026 if (!buf_iter)
4027 return;
4028
4029 ring_buffer_iter_reset(buf_iter);
4030
4031 /*
4032 * We could have the case with the max latency tracers
4033 * that a reset never took place on a cpu. This is evident
4034 * by the timestamp being before the start of the buffer.
4035 */
4036 while (ring_buffer_iter_peek(buf_iter, &ts)) {
4037 if (ts >= iter->array_buffer->time_start)
4038 break;
4039 entries++;
4040 ring_buffer_iter_advance(buf_iter);
4041 }
4042
4043 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = entries;
4044}
4045
4046/*
4047 * The current tracer is copied to avoid a global locking
4048 * all around.
4049 */
4050static void *s_start(struct seq_file *m, loff_t *pos)
4051{
4052 struct trace_iterator *iter = m->private;
4053 struct trace_array *tr = iter->tr;
4054 int cpu_file = iter->cpu_file;
4055 void *p = NULL;
4056 loff_t l = 0;
4057 int cpu;
4058
4059 /*
4060 * copy the tracer to avoid using a global lock all around.
4061 * iter->trace is a copy of current_trace, the pointer to the
4062 * name may be used instead of a strcmp(), as iter->trace->name
4063 * will point to the same string as current_trace->name.
4064 */
4065 mutex_lock(&trace_types_lock);
4066 if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
4067 *iter->trace = *tr->current_trace;
4068 mutex_unlock(&trace_types_lock);
4069
4070#ifdef CONFIG_TRACER_MAX_TRACE
4071 if (iter->snapshot && iter->trace->use_max_tr)
4072 return ERR_PTR(-EBUSY);
4073#endif
4074
4075 if (*pos != iter->pos) {
4076 iter->ent = NULL;
4077 iter->cpu = 0;
4078 iter->idx = -1;
4079
4080 if (cpu_file == RING_BUFFER_ALL_CPUS) {
4081 for_each_tracing_cpu(cpu)
4082 tracing_iter_reset(iter, cpu);
4083 } else
4084 tracing_iter_reset(iter, cpu_file);
4085
4086 iter->leftover = 0;
4087 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
4088 ;
4089
4090 } else {
4091 /*
4092 * If we overflowed the seq_file before, then we want
4093 * to just reuse the trace_seq buffer again.
4094 */
4095 if (iter->leftover)
4096 p = iter;
4097 else {
4098 l = *pos - 1;
4099 p = s_next(m, p, &l);
4100 }
4101 }
4102
4103 trace_event_read_lock();
4104 trace_access_lock(cpu_file);
4105 return p;
4106}
4107
4108static void s_stop(struct seq_file *m, void *p)
4109{
4110 struct trace_iterator *iter = m->private;
4111
4112#ifdef CONFIG_TRACER_MAX_TRACE
4113 if (iter->snapshot && iter->trace->use_max_tr)
4114 return;
4115#endif
4116
4117 trace_access_unlock(iter->cpu_file);
4118 trace_event_read_unlock();
4119}
4120
4121static void
4122get_total_entries_cpu(struct array_buffer *buf, unsigned long *total,
4123 unsigned long *entries, int cpu)
4124{
4125 unsigned long count;
4126
4127 count = ring_buffer_entries_cpu(buf->buffer, cpu);
4128 /*
4129 * If this buffer has skipped entries, then we hold all
4130 * entries for the trace and we need to ignore the
4131 * ones before the time stamp.
4132 */
4133 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
4134 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
4135 /* total is the same as the entries */
4136 *total = count;
4137 } else
4138 *total = count +
4139 ring_buffer_overrun_cpu(buf->buffer, cpu);
4140 *entries = count;
4141}
4142
4143static void
4144get_total_entries(struct array_buffer *buf,
4145 unsigned long *total, unsigned long *entries)
4146{
4147 unsigned long t, e;
4148 int cpu;
4149
4150 *total = 0;
4151 *entries = 0;
4152
4153 for_each_tracing_cpu(cpu) {
4154 get_total_entries_cpu(buf, &t, &e, cpu);
4155 *total += t;
4156 *entries += e;
4157 }
4158}
4159
4160unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
4161{
4162 unsigned long total, entries;
4163
4164 if (!tr)
4165 tr = &global_trace;
4166
4167 get_total_entries_cpu(&tr->array_buffer, &total, &entries, cpu);
4168
4169 return entries;
4170}
4171
4172unsigned long trace_total_entries(struct trace_array *tr)
4173{
4174 unsigned long total, entries;
4175
4176 if (!tr)
4177 tr = &global_trace;
4178
4179 get_total_entries(&tr->array_buffer, &total, &entries);
4180
4181 return entries;
4182}
4183
4184static void print_lat_help_header(struct seq_file *m)
4185{
4186 seq_puts(m, "# _------=> CPU# \n"
4187 "# / _-----=> irqs-off \n"
4188 "# | / _----=> need-resched \n"
4189 "# || / _---=> hardirq/softirq \n"
4190 "# ||| / _--=> preempt-depth \n"
4191 "# |||| / delay \n"
4192 "# cmd pid ||||| time | caller \n"
4193 "# \\ / ||||| \\ | / \n");
4194}
4195
4196static void print_event_info(struct array_buffer *buf, struct seq_file *m)
4197{
4198 unsigned long total;
4199 unsigned long entries;
4200
4201 get_total_entries(buf, &total, &entries);
4202 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
4203 entries, total, num_online_cpus());
4204 seq_puts(m, "#\n");
4205}
4206
4207static void print_func_help_header(struct array_buffer *buf, struct seq_file *m,
4208 unsigned int flags)
4209{
4210 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4211
4212 print_event_info(buf, m);
4213
4214 seq_printf(m, "# TASK-PID %s CPU# TIMESTAMP FUNCTION\n", tgid ? " TGID " : "");
4215 seq_printf(m, "# | | %s | | |\n", tgid ? " | " : "");
4216}
4217
4218static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file *m,
4219 unsigned int flags)
4220{
4221 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4222 const char *space = " ";
4223 int prec = tgid ? 12 : 2;
4224
4225 print_event_info(buf, m);
4226
4227 seq_printf(m, "# %.*s _-----=> irqs-off\n", prec, space);
4228 seq_printf(m, "# %.*s / _----=> need-resched\n", prec, space);
4229 seq_printf(m, "# %.*s| / _---=> hardirq/softirq\n", prec, space);
4230 seq_printf(m, "# %.*s|| / _--=> preempt-depth\n", prec, space);
4231 seq_printf(m, "# %.*s||| / delay\n", prec, space);
4232 seq_printf(m, "# TASK-PID %.*s CPU# |||| TIMESTAMP FUNCTION\n", prec, " TGID ");
4233 seq_printf(m, "# | | %.*s | |||| | |\n", prec, " | ");
4234}
4235
4236void
4237print_trace_header(struct seq_file *m, struct trace_iterator *iter)
4238{
4239 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
4240 struct array_buffer *buf = iter->array_buffer;
4241 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
4242 struct tracer *type = iter->trace;
4243 unsigned long entries;
4244 unsigned long total;
4245 const char *name = "preemption";
4246
4247 name = type->name;
4248
4249 get_total_entries(buf, &total, &entries);
4250
4251 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
4252 name, UTS_RELEASE);
4253 seq_puts(m, "# -----------------------------------"
4254 "---------------------------------\n");
4255 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
4256 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
4257 nsecs_to_usecs(data->saved_latency),
4258 entries,
4259 total,
4260 buf->cpu,
4261#if defined(CONFIG_PREEMPT_NONE)
4262 "server",
4263#elif defined(CONFIG_PREEMPT_VOLUNTARY)
4264 "desktop",
4265#elif defined(CONFIG_PREEMPT)
4266 "preempt",
4267#elif defined(CONFIG_PREEMPT_RT)
4268 "preempt_rt",
4269#else
4270 "unknown",
4271#endif
4272 /* These are reserved for later use */
4273 0, 0, 0, 0);
4274#ifdef CONFIG_SMP
4275 seq_printf(m, " #P:%d)\n", num_online_cpus());
4276#else
4277 seq_puts(m, ")\n");
4278#endif
4279 seq_puts(m, "# -----------------\n");
4280 seq_printf(m, "# | task: %.16s-%d "
4281 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
4282 data->comm, data->pid,
4283 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
4284 data->policy, data->rt_priority);
4285 seq_puts(m, "# -----------------\n");
4286
4287 if (data->critical_start) {
4288 seq_puts(m, "# => started at: ");
4289 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
4290 trace_print_seq(m, &iter->seq);
4291 seq_puts(m, "\n# => ended at: ");
4292 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
4293 trace_print_seq(m, &iter->seq);
4294 seq_puts(m, "\n#\n");
4295 }
4296
4297 seq_puts(m, "#\n");
4298}
4299
4300static void test_cpu_buff_start(struct trace_iterator *iter)
4301{
4302 struct trace_seq *s = &iter->seq;
4303 struct trace_array *tr = iter->tr;
4304
4305 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
4306 return;
4307
4308 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
4309 return;
4310
4311 if (cpumask_available(iter->started) &&
4312 cpumask_test_cpu(iter->cpu, iter->started))
4313 return;
4314
4315 if (per_cpu_ptr(iter->array_buffer->data, iter->cpu)->skipped_entries)
4316 return;
4317
4318 if (cpumask_available(iter->started))
4319 cpumask_set_cpu(iter->cpu, iter->started);
4320
4321 /* Don't print started cpu buffer for the first entry of the trace */
4322 if (iter->idx > 1)
4323 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
4324 iter->cpu);
4325}
4326
4327static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
4328{
4329 struct trace_array *tr = iter->tr;
4330 struct trace_seq *s = &iter->seq;
4331 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
4332 struct trace_entry *entry;
4333 struct trace_event *event;
4334
4335 entry = iter->ent;
4336
4337 test_cpu_buff_start(iter);
4338
4339 event = ftrace_find_event(entry->type);
4340
4341 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4342 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4343 trace_print_lat_context(iter);
4344 else
4345 trace_print_context(iter);
4346 }
4347
4348 if (trace_seq_has_overflowed(s))
4349 return TRACE_TYPE_PARTIAL_LINE;
4350
4351 if (event)
4352 return event->funcs->trace(iter, sym_flags, event);
4353
4354 trace_seq_printf(s, "Unknown type %d\n", entry->type);
4355
4356 return trace_handle_return(s);
4357}
4358
4359static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
4360{
4361 struct trace_array *tr = iter->tr;
4362 struct trace_seq *s = &iter->seq;
4363 struct trace_entry *entry;
4364 struct trace_event *event;
4365
4366 entry = iter->ent;
4367
4368 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
4369 trace_seq_printf(s, "%d %d %llu ",
4370 entry->pid, iter->cpu, iter->ts);
4371
4372 if (trace_seq_has_overflowed(s))
4373 return TRACE_TYPE_PARTIAL_LINE;
4374
4375 event = ftrace_find_event(entry->type);
4376 if (event)
4377 return event->funcs->raw(iter, 0, event);
4378
4379 trace_seq_printf(s, "%d ?\n", entry->type);
4380
4381 return trace_handle_return(s);
4382}
4383
4384static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
4385{
4386 struct trace_array *tr = iter->tr;
4387 struct trace_seq *s = &iter->seq;
4388 unsigned char newline = '\n';
4389 struct trace_entry *entry;
4390 struct trace_event *event;
4391
4392 entry = iter->ent;
4393
4394 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4395 SEQ_PUT_HEX_FIELD(s, entry->pid);
4396 SEQ_PUT_HEX_FIELD(s, iter->cpu);
4397 SEQ_PUT_HEX_FIELD(s, iter->ts);
4398 if (trace_seq_has_overflowed(s))
4399 return TRACE_TYPE_PARTIAL_LINE;
4400 }
4401
4402 event = ftrace_find_event(entry->type);
4403 if (event) {
4404 enum print_line_t ret = event->funcs->hex(iter, 0, event);
4405 if (ret != TRACE_TYPE_HANDLED)
4406 return ret;
4407 }
4408
4409 SEQ_PUT_FIELD(s, newline);
4410
4411 return trace_handle_return(s);
4412}
4413
4414static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
4415{
4416 struct trace_array *tr = iter->tr;
4417 struct trace_seq *s = &iter->seq;
4418 struct trace_entry *entry;
4419 struct trace_event *event;
4420
4421 entry = iter->ent;
4422
4423 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4424 SEQ_PUT_FIELD(s, entry->pid);
4425 SEQ_PUT_FIELD(s, iter->cpu);
4426 SEQ_PUT_FIELD(s, iter->ts);
4427 if (trace_seq_has_overflowed(s))
4428 return TRACE_TYPE_PARTIAL_LINE;
4429 }
4430
4431 event = ftrace_find_event(entry->type);
4432 return event ? event->funcs->binary(iter, 0, event) :
4433 TRACE_TYPE_HANDLED;
4434}
4435
4436int trace_empty(struct trace_iterator *iter)
4437{
4438 struct ring_buffer_iter *buf_iter;
4439 int cpu;
4440
4441 /* If we are looking at one CPU buffer, only check that one */
4442 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4443 cpu = iter->cpu_file;
4444 buf_iter = trace_buffer_iter(iter, cpu);
4445 if (buf_iter) {
4446 if (!ring_buffer_iter_empty(buf_iter))
4447 return 0;
4448 } else {
4449 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4450 return 0;
4451 }
4452 return 1;
4453 }
4454
4455 for_each_tracing_cpu(cpu) {
4456 buf_iter = trace_buffer_iter(iter, cpu);
4457 if (buf_iter) {
4458 if (!ring_buffer_iter_empty(buf_iter))
4459 return 0;
4460 } else {
4461 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4462 return 0;
4463 }
4464 }
4465
4466 return 1;
4467}
4468
4469/* Called with trace_event_read_lock() held. */
4470enum print_line_t print_trace_line(struct trace_iterator *iter)
4471{
4472 struct trace_array *tr = iter->tr;
4473 unsigned long trace_flags = tr->trace_flags;
4474 enum print_line_t ret;
4475
4476 if (iter->lost_events) {
4477 if (iter->lost_events == (unsigned long)-1)
4478 trace_seq_printf(&iter->seq, "CPU:%d [LOST EVENTS]\n",
4479 iter->cpu);
4480 else
4481 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
4482 iter->cpu, iter->lost_events);
4483 if (trace_seq_has_overflowed(&iter->seq))
4484 return TRACE_TYPE_PARTIAL_LINE;
4485 }
4486
4487 if (iter->trace && iter->trace->print_line) {
4488 ret = iter->trace->print_line(iter);
4489 if (ret != TRACE_TYPE_UNHANDLED)
4490 return ret;
4491 }
4492
4493 if (iter->ent->type == TRACE_BPUTS &&
4494 trace_flags & TRACE_ITER_PRINTK &&
4495 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4496 return trace_print_bputs_msg_only(iter);
4497
4498 if (iter->ent->type == TRACE_BPRINT &&
4499 trace_flags & TRACE_ITER_PRINTK &&
4500 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4501 return trace_print_bprintk_msg_only(iter);
4502
4503 if (iter->ent->type == TRACE_PRINT &&
4504 trace_flags & TRACE_ITER_PRINTK &&
4505 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4506 return trace_print_printk_msg_only(iter);
4507
4508 if (trace_flags & TRACE_ITER_BIN)
4509 return print_bin_fmt(iter);
4510
4511 if (trace_flags & TRACE_ITER_HEX)
4512 return print_hex_fmt(iter);
4513
4514 if (trace_flags & TRACE_ITER_RAW)
4515 return print_raw_fmt(iter);
4516
4517 return print_trace_fmt(iter);
4518}
4519
4520void trace_latency_header(struct seq_file *m)
4521{
4522 struct trace_iterator *iter = m->private;
4523 struct trace_array *tr = iter->tr;
4524
4525 /* print nothing if the buffers are empty */
4526 if (trace_empty(iter))
4527 return;
4528
4529 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4530 print_trace_header(m, iter);
4531
4532 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
4533 print_lat_help_header(m);
4534}
4535
4536void trace_default_header(struct seq_file *m)
4537{
4538 struct trace_iterator *iter = m->private;
4539 struct trace_array *tr = iter->tr;
4540 unsigned long trace_flags = tr->trace_flags;
4541
4542 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
4543 return;
4544
4545 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
4546 /* print nothing if the buffers are empty */
4547 if (trace_empty(iter))
4548 return;
4549 print_trace_header(m, iter);
4550 if (!(trace_flags & TRACE_ITER_VERBOSE))
4551 print_lat_help_header(m);
4552 } else {
4553 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
4554 if (trace_flags & TRACE_ITER_IRQ_INFO)
4555 print_func_help_header_irq(iter->array_buffer,
4556 m, trace_flags);
4557 else
4558 print_func_help_header(iter->array_buffer, m,
4559 trace_flags);
4560 }
4561 }
4562}
4563
4564static void test_ftrace_alive(struct seq_file *m)
4565{
4566 if (!ftrace_is_dead())
4567 return;
4568 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
4569 "# MAY BE MISSING FUNCTION EVENTS\n");
4570}
4571
4572#ifdef CONFIG_TRACER_MAX_TRACE
4573static void show_snapshot_main_help(struct seq_file *m)
4574{
4575 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
4576 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4577 "# Takes a snapshot of the main buffer.\n"
4578 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
4579 "# (Doesn't have to be '2' works with any number that\n"
4580 "# is not a '0' or '1')\n");
4581}
4582
4583static void show_snapshot_percpu_help(struct seq_file *m)
4584{
4585 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
4586#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
4587 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4588 "# Takes a snapshot of the main buffer for this cpu.\n");
4589#else
4590 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
4591 "# Must use main snapshot file to allocate.\n");
4592#endif
4593 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
4594 "# (Doesn't have to be '2' works with any number that\n"
4595 "# is not a '0' or '1')\n");
4596}
4597
4598static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
4599{
4600 if (iter->tr->allocated_snapshot)
4601 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
4602 else
4603 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
4604
4605 seq_puts(m, "# Snapshot commands:\n");
4606 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4607 show_snapshot_main_help(m);
4608 else
4609 show_snapshot_percpu_help(m);
4610}
4611#else
4612/* Should never be called */
4613static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
4614#endif
4615
4616static int s_show(struct seq_file *m, void *v)
4617{
4618 struct trace_iterator *iter = v;
4619 int ret;
4620
4621 if (iter->ent == NULL) {
4622 if (iter->tr) {
4623 seq_printf(m, "# tracer: %s\n", iter->trace->name);
4624 seq_puts(m, "#\n");
4625 test_ftrace_alive(m);
4626 }
4627 if (iter->snapshot && trace_empty(iter))
4628 print_snapshot_help(m, iter);
4629 else if (iter->trace && iter->trace->print_header)
4630 iter->trace->print_header(m);
4631 else
4632 trace_default_header(m);
4633
4634 } else if (iter->leftover) {
4635 /*
4636 * If we filled the seq_file buffer earlier, we
4637 * want to just show it now.
4638 */
4639 ret = trace_print_seq(m, &iter->seq);
4640
4641 /* ret should this time be zero, but you never know */
4642 iter->leftover = ret;
4643
4644 } else {
4645 print_trace_line(iter);
4646 ret = trace_print_seq(m, &iter->seq);
4647 /*
4648 * If we overflow the seq_file buffer, then it will
4649 * ask us for this data again at start up.
4650 * Use that instead.
4651 * ret is 0 if seq_file write succeeded.
4652 * -1 otherwise.
4653 */
4654 iter->leftover = ret;
4655 }
4656
4657 return 0;
4658}
4659
4660/*
4661 * Should be used after trace_array_get(), trace_types_lock
4662 * ensures that i_cdev was already initialized.
4663 */
4664static inline int tracing_get_cpu(struct inode *inode)
4665{
4666 if (inode->i_cdev) /* See trace_create_cpu_file() */
4667 return (long)inode->i_cdev - 1;
4668 return RING_BUFFER_ALL_CPUS;
4669}
4670
4671static const struct seq_operations tracer_seq_ops = {
4672 .start = s_start,
4673 .next = s_next,
4674 .stop = s_stop,
4675 .show = s_show,
4676};
4677
4678static struct trace_iterator *
4679__tracing_open(struct inode *inode, struct file *file, bool snapshot)
4680{
4681 struct trace_array *tr = inode->i_private;
4682 struct trace_iterator *iter;
4683 int cpu;
4684
4685 if (tracing_disabled)
4686 return ERR_PTR(-ENODEV);
4687
4688 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
4689 if (!iter)
4690 return ERR_PTR(-ENOMEM);
4691
4692 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
4693 GFP_KERNEL);
4694 if (!iter->buffer_iter)
4695 goto release;
4696
4697 /*
4698 * trace_find_next_entry() may need to save off iter->ent.
4699 * It will place it into the iter->temp buffer. As most
4700 * events are less than 128, allocate a buffer of that size.
4701 * If one is greater, then trace_find_next_entry() will
4702 * allocate a new buffer to adjust for the bigger iter->ent.
4703 * It's not critical if it fails to get allocated here.
4704 */
4705 iter->temp = kmalloc(128, GFP_KERNEL);
4706 if (iter->temp)
4707 iter->temp_size = 128;
4708
4709 /*
4710 * trace_event_printf() may need to modify given format
4711 * string to replace %p with %px so that it shows real address
4712 * instead of hash value. However, that is only for the event
4713 * tracing, other tracer may not need. Defer the allocation
4714 * until it is needed.
4715 */
4716 iter->fmt = NULL;
4717 iter->fmt_size = 0;
4718
4719 /*
4720 * We make a copy of the current tracer to avoid concurrent
4721 * changes on it while we are reading.
4722 */
4723 mutex_lock(&trace_types_lock);
4724 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
4725 if (!iter->trace)
4726 goto fail;
4727
4728 *iter->trace = *tr->current_trace;
4729
4730 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
4731 goto fail;
4732
4733 iter->tr = tr;
4734
4735#ifdef CONFIG_TRACER_MAX_TRACE
4736 /* Currently only the top directory has a snapshot */
4737 if (tr->current_trace->print_max || snapshot)
4738 iter->array_buffer = &tr->max_buffer;
4739 else
4740#endif
4741 iter->array_buffer = &tr->array_buffer;
4742 iter->snapshot = snapshot;
4743 iter->pos = -1;
4744 iter->cpu_file = tracing_get_cpu(inode);
4745 mutex_init(&iter->mutex);
4746
4747 /* Notify the tracer early; before we stop tracing. */
4748 if (iter->trace->open)
4749 iter->trace->open(iter);
4750
4751 /* Annotate start of buffers if we had overruns */
4752 if (ring_buffer_overruns(iter->array_buffer->buffer))
4753 iter->iter_flags |= TRACE_FILE_ANNOTATE;
4754
4755 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4756 if (trace_clocks[tr->clock_id].in_ns)
4757 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4758
4759 /*
4760 * If pause-on-trace is enabled, then stop the trace while
4761 * dumping, unless this is the "snapshot" file
4762 */
4763 if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE))
4764 tracing_stop_tr(tr);
4765
4766 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
4767 for_each_tracing_cpu(cpu) {
4768 iter->buffer_iter[cpu] =
4769 ring_buffer_read_prepare(iter->array_buffer->buffer,
4770 cpu, GFP_KERNEL);
4771 }
4772 ring_buffer_read_prepare_sync();
4773 for_each_tracing_cpu(cpu) {
4774 ring_buffer_read_start(iter->buffer_iter[cpu]);
4775 tracing_iter_reset(iter, cpu);
4776 }
4777 } else {
4778 cpu = iter->cpu_file;
4779 iter->buffer_iter[cpu] =
4780 ring_buffer_read_prepare(iter->array_buffer->buffer,
4781 cpu, GFP_KERNEL);
4782 ring_buffer_read_prepare_sync();
4783 ring_buffer_read_start(iter->buffer_iter[cpu]);
4784 tracing_iter_reset(iter, cpu);
4785 }
4786
4787 mutex_unlock(&trace_types_lock);
4788
4789 return iter;
4790
4791 fail:
4792 mutex_unlock(&trace_types_lock);
4793 kfree(iter->trace);
4794 kfree(iter->temp);
4795 kfree(iter->buffer_iter);
4796release:
4797 seq_release_private(inode, file);
4798 return ERR_PTR(-ENOMEM);
4799}
4800
4801int tracing_open_generic(struct inode *inode, struct file *filp)
4802{
4803 int ret;
4804
4805 ret = tracing_check_open_get_tr(NULL);
4806 if (ret)
4807 return ret;
4808
4809 filp->private_data = inode->i_private;
4810 return 0;
4811}
4812
4813bool tracing_is_disabled(void)
4814{
4815 return (tracing_disabled) ? true: false;
4816}
4817
4818/*
4819 * Open and update trace_array ref count.
4820 * Must have the current trace_array passed to it.
4821 */
4822int tracing_open_generic_tr(struct inode *inode, struct file *filp)
4823{
4824 struct trace_array *tr = inode->i_private;
4825 int ret;
4826
4827 ret = tracing_check_open_get_tr(tr);
4828 if (ret)
4829 return ret;
4830
4831 filp->private_data = inode->i_private;
4832
4833 return 0;
4834}
4835
4836static int tracing_release(struct inode *inode, struct file *file)
4837{
4838 struct trace_array *tr = inode->i_private;
4839 struct seq_file *m = file->private_data;
4840 struct trace_iterator *iter;
4841 int cpu;
4842
4843 if (!(file->f_mode & FMODE_READ)) {
4844 trace_array_put(tr);
4845 return 0;
4846 }
4847
4848 /* Writes do not use seq_file */
4849 iter = m->private;
4850 mutex_lock(&trace_types_lock);
4851
4852 for_each_tracing_cpu(cpu) {
4853 if (iter->buffer_iter[cpu])
4854 ring_buffer_read_finish(iter->buffer_iter[cpu]);
4855 }
4856
4857 if (iter->trace && iter->trace->close)
4858 iter->trace->close(iter);
4859
4860 if (!iter->snapshot && tr->stop_count)
4861 /* reenable tracing if it was previously enabled */
4862 tracing_start_tr(tr);
4863
4864 __trace_array_put(tr);
4865
4866 mutex_unlock(&trace_types_lock);
4867
4868 mutex_destroy(&iter->mutex);
4869 free_cpumask_var(iter->started);
4870 kfree(iter->fmt);
4871 kfree(iter->temp);
4872 kfree(iter->trace);
4873 kfree(iter->buffer_iter);
4874 seq_release_private(inode, file);
4875
4876 return 0;
4877}
4878
4879static int tracing_release_generic_tr(struct inode *inode, struct file *file)
4880{
4881 struct trace_array *tr = inode->i_private;
4882
4883 trace_array_put(tr);
4884 return 0;
4885}
4886
4887static int tracing_single_release_tr(struct inode *inode, struct file *file)
4888{
4889 struct trace_array *tr = inode->i_private;
4890
4891 trace_array_put(tr);
4892
4893 return single_release(inode, file);
4894}
4895
4896static int tracing_open(struct inode *inode, struct file *file)
4897{
4898 struct trace_array *tr = inode->i_private;
4899 struct trace_iterator *iter;
4900 int ret;
4901
4902 ret = tracing_check_open_get_tr(tr);
4903 if (ret)
4904 return ret;
4905
4906 /* If this file was open for write, then erase contents */
4907 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
4908 int cpu = tracing_get_cpu(inode);
4909 struct array_buffer *trace_buf = &tr->array_buffer;
4910
4911#ifdef CONFIG_TRACER_MAX_TRACE
4912 if (tr->current_trace->print_max)
4913 trace_buf = &tr->max_buffer;
4914#endif
4915
4916 if (cpu == RING_BUFFER_ALL_CPUS)
4917 tracing_reset_online_cpus(trace_buf);
4918 else
4919 tracing_reset_cpu(trace_buf, cpu);
4920 }
4921
4922 if (file->f_mode & FMODE_READ) {
4923 iter = __tracing_open(inode, file, false);
4924 if (IS_ERR(iter))
4925 ret = PTR_ERR(iter);
4926 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
4927 iter->iter_flags |= TRACE_FILE_LAT_FMT;
4928 }
4929
4930 if (ret < 0)
4931 trace_array_put(tr);
4932
4933 return ret;
4934}
4935
4936/*
4937 * Some tracers are not suitable for instance buffers.
4938 * A tracer is always available for the global array (toplevel)
4939 * or if it explicitly states that it is.
4940 */
4941static bool
4942trace_ok_for_array(struct tracer *t, struct trace_array *tr)
4943{
4944 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
4945}
4946
4947/* Find the next tracer that this trace array may use */
4948static struct tracer *
4949get_tracer_for_array(struct trace_array *tr, struct tracer *t)
4950{
4951 while (t && !trace_ok_for_array(t, tr))
4952 t = t->next;
4953
4954 return t;
4955}
4956
4957static void *
4958t_next(struct seq_file *m, void *v, loff_t *pos)
4959{
4960 struct trace_array *tr = m->private;
4961 struct tracer *t = v;
4962
4963 (*pos)++;
4964
4965 if (t)
4966 t = get_tracer_for_array(tr, t->next);
4967
4968 return t;
4969}
4970
4971static void *t_start(struct seq_file *m, loff_t *pos)
4972{
4973 struct trace_array *tr = m->private;
4974 struct tracer *t;
4975 loff_t l = 0;
4976
4977 mutex_lock(&trace_types_lock);
4978
4979 t = get_tracer_for_array(tr, trace_types);
4980 for (; t && l < *pos; t = t_next(m, t, &l))
4981 ;
4982
4983 return t;
4984}
4985
4986static void t_stop(struct seq_file *m, void *p)
4987{
4988 mutex_unlock(&trace_types_lock);
4989}
4990
4991static int t_show(struct seq_file *m, void *v)
4992{
4993 struct tracer *t = v;
4994
4995 if (!t)
4996 return 0;
4997
4998 seq_puts(m, t->name);
4999 if (t->next)
5000 seq_putc(m, ' ');
5001 else
5002 seq_putc(m, '\n');
5003
5004 return 0;
5005}
5006
5007static const struct seq_operations show_traces_seq_ops = {
5008 .start = t_start,
5009 .next = t_next,
5010 .stop = t_stop,
5011 .show = t_show,
5012};
5013
5014static int show_traces_open(struct inode *inode, struct file *file)
5015{
5016 struct trace_array *tr = inode->i_private;
5017 struct seq_file *m;
5018 int ret;
5019
5020 ret = tracing_check_open_get_tr(tr);
5021 if (ret)
5022 return ret;
5023
5024 ret = seq_open(file, &show_traces_seq_ops);
5025 if (ret) {
5026 trace_array_put(tr);
5027 return ret;
5028 }
5029
5030 m = file->private_data;
5031 m->private = tr;
5032
5033 return 0;
5034}
5035
5036static int show_traces_release(struct inode *inode, struct file *file)
5037{
5038 struct trace_array *tr = inode->i_private;
5039
5040 trace_array_put(tr);
5041 return seq_release(inode, file);
5042}
5043
5044static ssize_t
5045tracing_write_stub(struct file *filp, const char __user *ubuf,
5046 size_t count, loff_t *ppos)
5047{
5048 return count;
5049}
5050
5051loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
5052{
5053 int ret;
5054
5055 if (file->f_mode & FMODE_READ)
5056 ret = seq_lseek(file, offset, whence);
5057 else
5058 file->f_pos = ret = 0;
5059
5060 return ret;
5061}
5062
5063static const struct file_operations tracing_fops = {
5064 .open = tracing_open,
5065 .read = seq_read,
5066 .write = tracing_write_stub,
5067 .llseek = tracing_lseek,
5068 .release = tracing_release,
5069};
5070
5071static const struct file_operations show_traces_fops = {
5072 .open = show_traces_open,
5073 .read = seq_read,
5074 .llseek = seq_lseek,
5075 .release = show_traces_release,
5076};
5077
5078static ssize_t
5079tracing_cpumask_read(struct file *filp, char __user *ubuf,
5080 size_t count, loff_t *ppos)
5081{
5082 struct trace_array *tr = file_inode(filp)->i_private;
5083 char *mask_str;
5084 int len;
5085
5086 len = snprintf(NULL, 0, "%*pb\n",
5087 cpumask_pr_args(tr->tracing_cpumask)) + 1;
5088 mask_str = kmalloc(len, GFP_KERNEL);
5089 if (!mask_str)
5090 return -ENOMEM;
5091
5092 len = snprintf(mask_str, len, "%*pb\n",
5093 cpumask_pr_args(tr->tracing_cpumask));
5094 if (len >= count) {
5095 count = -EINVAL;
5096 goto out_err;
5097 }
5098 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
5099
5100out_err:
5101 kfree(mask_str);
5102
5103 return count;
5104}
5105
5106int tracing_set_cpumask(struct trace_array *tr,
5107 cpumask_var_t tracing_cpumask_new)
5108{
5109 int cpu;
5110
5111 if (!tr)
5112 return -EINVAL;
5113
5114 local_irq_disable();
5115 arch_spin_lock(&tr->max_lock);
5116 for_each_tracing_cpu(cpu) {
5117 /*
5118 * Increase/decrease the disabled counter if we are
5119 * about to flip a bit in the cpumask:
5120 */
5121 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5122 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5123 atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5124 ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
5125 }
5126 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5127 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5128 atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5129 ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
5130 }
5131 }
5132 arch_spin_unlock(&tr->max_lock);
5133 local_irq_enable();
5134
5135 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
5136
5137 return 0;
5138}
5139
5140static ssize_t
5141tracing_cpumask_write(struct file *filp, const char __user *ubuf,
5142 size_t count, loff_t *ppos)
5143{
5144 struct trace_array *tr = file_inode(filp)->i_private;
5145 cpumask_var_t tracing_cpumask_new;
5146 int err;
5147
5148 if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
5149 return -ENOMEM;
5150
5151 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
5152 if (err)
5153 goto err_free;
5154
5155 err = tracing_set_cpumask(tr, tracing_cpumask_new);
5156 if (err)
5157 goto err_free;
5158
5159 free_cpumask_var(tracing_cpumask_new);
5160
5161 return count;
5162
5163err_free:
5164 free_cpumask_var(tracing_cpumask_new);
5165
5166 return err;
5167}
5168
5169static const struct file_operations tracing_cpumask_fops = {
5170 .open = tracing_open_generic_tr,
5171 .read = tracing_cpumask_read,
5172 .write = tracing_cpumask_write,
5173 .release = tracing_release_generic_tr,
5174 .llseek = generic_file_llseek,
5175};
5176
5177static int tracing_trace_options_show(struct seq_file *m, void *v)
5178{
5179 struct tracer_opt *trace_opts;
5180 struct trace_array *tr = m->private;
5181 u32 tracer_flags;
5182 int i;
5183
5184 mutex_lock(&trace_types_lock);
5185 tracer_flags = tr->current_trace->flags->val;
5186 trace_opts = tr->current_trace->flags->opts;
5187
5188 for (i = 0; trace_options[i]; i++) {
5189 if (tr->trace_flags & (1 << i))
5190 seq_printf(m, "%s\n", trace_options[i]);
5191 else
5192 seq_printf(m, "no%s\n", trace_options[i]);
5193 }
5194
5195 for (i = 0; trace_opts[i].name; i++) {
5196 if (tracer_flags & trace_opts[i].bit)
5197 seq_printf(m, "%s\n", trace_opts[i].name);
5198 else
5199 seq_printf(m, "no%s\n", trace_opts[i].name);
5200 }
5201 mutex_unlock(&trace_types_lock);
5202
5203 return 0;
5204}
5205
5206static int __set_tracer_option(struct trace_array *tr,
5207 struct tracer_flags *tracer_flags,
5208 struct tracer_opt *opts, int neg)
5209{
5210 struct tracer *trace = tracer_flags->trace;
5211 int ret;
5212
5213 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
5214 if (ret)
5215 return ret;
5216
5217 if (neg)
5218 tracer_flags->val &= ~opts->bit;
5219 else
5220 tracer_flags->val |= opts->bit;
5221 return 0;
5222}
5223
5224/* Try to assign a tracer specific option */
5225static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
5226{
5227 struct tracer *trace = tr->current_trace;
5228 struct tracer_flags *tracer_flags = trace->flags;
5229 struct tracer_opt *opts = NULL;
5230 int i;
5231
5232 for (i = 0; tracer_flags->opts[i].name; i++) {
5233 opts = &tracer_flags->opts[i];
5234
5235 if (strcmp(cmp, opts->name) == 0)
5236 return __set_tracer_option(tr, trace->flags, opts, neg);
5237 }
5238
5239 return -EINVAL;
5240}
5241
5242/* Some tracers require overwrite to stay enabled */
5243int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
5244{
5245 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
5246 return -1;
5247
5248 return 0;
5249}
5250
5251int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
5252{
5253 int *map;
5254
5255 if ((mask == TRACE_ITER_RECORD_TGID) ||
5256 (mask == TRACE_ITER_RECORD_CMD))
5257 lockdep_assert_held(&event_mutex);
5258
5259 /* do nothing if flag is already set */
5260 if (!!(tr->trace_flags & mask) == !!enabled)
5261 return 0;
5262
5263 /* Give the tracer a chance to approve the change */
5264 if (tr->current_trace->flag_changed)
5265 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
5266 return -EINVAL;
5267
5268 if (enabled)
5269 tr->trace_flags |= mask;
5270 else
5271 tr->trace_flags &= ~mask;
5272
5273 if (mask == TRACE_ITER_RECORD_CMD)
5274 trace_event_enable_cmd_record(enabled);
5275
5276 if (mask == TRACE_ITER_RECORD_TGID) {
5277 if (!tgid_map) {
5278 tgid_map_max = pid_max;
5279 map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map),
5280 GFP_KERNEL);
5281
5282 /*
5283 * Pairs with smp_load_acquire() in
5284 * trace_find_tgid_ptr() to ensure that if it observes
5285 * the tgid_map we just allocated then it also observes
5286 * the corresponding tgid_map_max value.
5287 */
5288 smp_store_release(&tgid_map, map);
5289 }
5290 if (!tgid_map) {
5291 tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
5292 return -ENOMEM;
5293 }
5294
5295 trace_event_enable_tgid_record(enabled);
5296 }
5297
5298 if (mask == TRACE_ITER_EVENT_FORK)
5299 trace_event_follow_fork(tr, enabled);
5300
5301 if (mask == TRACE_ITER_FUNC_FORK)
5302 ftrace_pid_follow_fork(tr, enabled);
5303
5304 if (mask == TRACE_ITER_OVERWRITE) {
5305 ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled);
5306#ifdef CONFIG_TRACER_MAX_TRACE
5307 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
5308#endif
5309 }
5310
5311 if (mask == TRACE_ITER_PRINTK) {
5312 trace_printk_start_stop_comm(enabled);
5313 trace_printk_control(enabled);
5314 }
5315
5316 return 0;
5317}
5318
5319int trace_set_options(struct trace_array *tr, char *option)
5320{
5321 char *cmp;
5322 int neg = 0;
5323 int ret;
5324 size_t orig_len = strlen(option);
5325 int len;
5326
5327 cmp = strstrip(option);
5328
5329 len = str_has_prefix(cmp, "no");
5330 if (len)
5331 neg = 1;
5332
5333 cmp += len;
5334
5335 mutex_lock(&event_mutex);
5336 mutex_lock(&trace_types_lock);
5337
5338 ret = match_string(trace_options, -1, cmp);
5339 /* If no option could be set, test the specific tracer options */
5340 if (ret < 0)
5341 ret = set_tracer_option(tr, cmp, neg);
5342 else
5343 ret = set_tracer_flag(tr, 1 << ret, !neg);
5344
5345 mutex_unlock(&trace_types_lock);
5346 mutex_unlock(&event_mutex);
5347
5348 /*
5349 * If the first trailing whitespace is replaced with '\0' by strstrip,
5350 * turn it back into a space.
5351 */
5352 if (orig_len > strlen(option))
5353 option[strlen(option)] = ' ';
5354
5355 return ret;
5356}
5357
5358static void __init apply_trace_boot_options(void)
5359{
5360 char *buf = trace_boot_options_buf;
5361 char *option;
5362
5363 while (true) {
5364 option = strsep(&buf, ",");
5365
5366 if (!option)
5367 break;
5368
5369 if (*option)
5370 trace_set_options(&global_trace, option);
5371
5372 /* Put back the comma to allow this to be called again */
5373 if (buf)
5374 *(buf - 1) = ',';
5375 }
5376}
5377
5378static ssize_t
5379tracing_trace_options_write(struct file *filp, const char __user *ubuf,
5380 size_t cnt, loff_t *ppos)
5381{
5382 struct seq_file *m = filp->private_data;
5383 struct trace_array *tr = m->private;
5384 char buf[64];
5385 int ret;
5386
5387 if (cnt >= sizeof(buf))
5388 return -EINVAL;
5389
5390 if (copy_from_user(buf, ubuf, cnt))
5391 return -EFAULT;
5392
5393 buf[cnt] = 0;
5394
5395 ret = trace_set_options(tr, buf);
5396 if (ret < 0)
5397 return ret;
5398
5399 *ppos += cnt;
5400
5401 return cnt;
5402}
5403
5404static int tracing_trace_options_open(struct inode *inode, struct file *file)
5405{
5406 struct trace_array *tr = inode->i_private;
5407 int ret;
5408
5409 ret = tracing_check_open_get_tr(tr);
5410 if (ret)
5411 return ret;
5412
5413 ret = single_open(file, tracing_trace_options_show, inode->i_private);
5414 if (ret < 0)
5415 trace_array_put(tr);
5416
5417 return ret;
5418}
5419
5420static const struct file_operations tracing_iter_fops = {
5421 .open = tracing_trace_options_open,
5422 .read = seq_read,
5423 .llseek = seq_lseek,
5424 .release = tracing_single_release_tr,
5425 .write = tracing_trace_options_write,
5426};
5427
5428static const char readme_msg[] =
5429 "tracing mini-HOWTO:\n\n"
5430 "# echo 0 > tracing_on : quick way to disable tracing\n"
5431 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
5432 " Important files:\n"
5433 " trace\t\t\t- The static contents of the buffer\n"
5434 "\t\t\t To clear the buffer write into this file: echo > trace\n"
5435 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
5436 " current_tracer\t- function and latency tracers\n"
5437 " available_tracers\t- list of configured tracers for current_tracer\n"
5438 " error_log\t- error log for failed commands (that support it)\n"
5439 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
5440 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
5441 " trace_clock\t\t-change the clock used to order events\n"
5442 " local: Per cpu clock but may not be synced across CPUs\n"
5443 " global: Synced across CPUs but slows tracing down.\n"
5444 " counter: Not a clock, but just an increment\n"
5445 " uptime: Jiffy counter from time of boot\n"
5446 " perf: Same clock that perf events use\n"
5447#ifdef CONFIG_X86_64
5448 " x86-tsc: TSC cycle counter\n"
5449#endif
5450 "\n timestamp_mode\t-view the mode used to timestamp events\n"
5451 " delta: Delta difference against a buffer-wide timestamp\n"
5452 " absolute: Absolute (standalone) timestamp\n"
5453 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
5454 "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
5455 " tracing_cpumask\t- Limit which CPUs to trace\n"
5456 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
5457 "\t\t\t Remove sub-buffer with rmdir\n"
5458 " trace_options\t\t- Set format or modify how tracing happens\n"
5459 "\t\t\t Disable an option by prefixing 'no' to the\n"
5460 "\t\t\t option name\n"
5461 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
5462#ifdef CONFIG_DYNAMIC_FTRACE
5463 "\n available_filter_functions - list of functions that can be filtered on\n"
5464 " set_ftrace_filter\t- echo function name in here to only trace these\n"
5465 "\t\t\t functions\n"
5466 "\t accepts: func_full_name or glob-matching-pattern\n"
5467 "\t modules: Can select a group via module\n"
5468 "\t Format: :mod:<module-name>\n"
5469 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
5470 "\t triggers: a command to perform when function is hit\n"
5471 "\t Format: <function>:<trigger>[:count]\n"
5472 "\t trigger: traceon, traceoff\n"
5473 "\t\t enable_event:<system>:<event>\n"
5474 "\t\t disable_event:<system>:<event>\n"
5475#ifdef CONFIG_STACKTRACE
5476 "\t\t stacktrace\n"
5477#endif
5478#ifdef CONFIG_TRACER_SNAPSHOT
5479 "\t\t snapshot\n"
5480#endif
5481 "\t\t dump\n"
5482 "\t\t cpudump\n"
5483 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
5484 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
5485 "\t The first one will disable tracing every time do_fault is hit\n"
5486 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
5487 "\t The first time do trap is hit and it disables tracing, the\n"
5488 "\t counter will decrement to 2. If tracing is already disabled,\n"
5489 "\t the counter will not decrement. It only decrements when the\n"
5490 "\t trigger did work\n"
5491 "\t To remove trigger without count:\n"
5492 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
5493 "\t To remove trigger with a count:\n"
5494 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
5495 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
5496 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
5497 "\t modules: Can select a group via module command :mod:\n"
5498 "\t Does not accept triggers\n"
5499#endif /* CONFIG_DYNAMIC_FTRACE */
5500#ifdef CONFIG_FUNCTION_TRACER
5501 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
5502 "\t\t (function)\n"
5503 " set_ftrace_notrace_pid\t- Write pid(s) to not function trace those pids\n"
5504 "\t\t (function)\n"
5505#endif
5506#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5507 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
5508 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
5509 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
5510#endif
5511#ifdef CONFIG_TRACER_SNAPSHOT
5512 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
5513 "\t\t\t snapshot buffer. Read the contents for more\n"
5514 "\t\t\t information\n"
5515#endif
5516#ifdef CONFIG_STACK_TRACER
5517 " stack_trace\t\t- Shows the max stack trace when active\n"
5518 " stack_max_size\t- Shows current max stack size that was traced\n"
5519 "\t\t\t Write into this file to reset the max size (trigger a\n"
5520 "\t\t\t new trace)\n"
5521#ifdef CONFIG_DYNAMIC_FTRACE
5522 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
5523 "\t\t\t traces\n"
5524#endif
5525#endif /* CONFIG_STACK_TRACER */
5526#ifdef CONFIG_DYNAMIC_EVENTS
5527 " dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
5528 "\t\t\t Write into this file to define/undefine new trace events.\n"
5529#endif
5530#ifdef CONFIG_KPROBE_EVENTS
5531 " kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
5532 "\t\t\t Write into this file to define/undefine new trace events.\n"
5533#endif
5534#ifdef CONFIG_UPROBE_EVENTS
5535 " uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
5536 "\t\t\t Write into this file to define/undefine new trace events.\n"
5537#endif
5538#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
5539 "\t accepts: event-definitions (one definition per line)\n"
5540 "\t Format: p[:[<group>/]<event>] <place> [<args>]\n"
5541 "\t r[maxactive][:[<group>/]<event>] <place> [<args>]\n"
5542#ifdef CONFIG_HIST_TRIGGERS
5543 "\t s:[synthetic/]<event> <field> [<field>]\n"
5544#endif
5545 "\t -:[<group>/]<event>\n"
5546#ifdef CONFIG_KPROBE_EVENTS
5547 "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
5548 "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n"
5549#endif
5550#ifdef CONFIG_UPROBE_EVENTS
5551 " place (uprobe): <path>:<offset>[%return][(ref_ctr_offset)]\n"
5552#endif
5553 "\t args: <name>=fetcharg[:type]\n"
5554 "\t fetcharg: %<register>, @<address>, @<symbol>[+|-<offset>],\n"
5555#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
5556 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
5557#else
5558 "\t $stack<index>, $stack, $retval, $comm,\n"
5559#endif
5560 "\t +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
5561 "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
5562 "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
5563 "\t <type>\\[<array-size>\\]\n"
5564#ifdef CONFIG_HIST_TRIGGERS
5565 "\t field: <stype> <name>;\n"
5566 "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
5567 "\t [unsigned] char/int/long\n"
5568#endif
5569#endif
5570 " events/\t\t- Directory containing all trace event subsystems:\n"
5571 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
5572 " events/<system>/\t- Directory containing all trace events for <system>:\n"
5573 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
5574 "\t\t\t events\n"
5575 " filter\t\t- If set, only events passing filter are traced\n"
5576 " events/<system>/<event>/\t- Directory containing control files for\n"
5577 "\t\t\t <event>:\n"
5578 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
5579 " filter\t\t- If set, only events passing filter are traced\n"
5580 " trigger\t\t- If set, a command to perform when event is hit\n"
5581 "\t Format: <trigger>[:count][if <filter>]\n"
5582 "\t trigger: traceon, traceoff\n"
5583 "\t enable_event:<system>:<event>\n"
5584 "\t disable_event:<system>:<event>\n"
5585#ifdef CONFIG_HIST_TRIGGERS
5586 "\t enable_hist:<system>:<event>\n"
5587 "\t disable_hist:<system>:<event>\n"
5588#endif
5589#ifdef CONFIG_STACKTRACE
5590 "\t\t stacktrace\n"
5591#endif
5592#ifdef CONFIG_TRACER_SNAPSHOT
5593 "\t\t snapshot\n"
5594#endif
5595#ifdef CONFIG_HIST_TRIGGERS
5596 "\t\t hist (see below)\n"
5597#endif
5598 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
5599 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
5600 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
5601 "\t events/block/block_unplug/trigger\n"
5602 "\t The first disables tracing every time block_unplug is hit.\n"
5603 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
5604 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
5605 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
5606 "\t Like function triggers, the counter is only decremented if it\n"
5607 "\t enabled or disabled tracing.\n"
5608 "\t To remove a trigger without a count:\n"
5609 "\t echo '!<trigger> > <system>/<event>/trigger\n"
5610 "\t To remove a trigger with a count:\n"
5611 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
5612 "\t Filters can be ignored when removing a trigger.\n"
5613#ifdef CONFIG_HIST_TRIGGERS
5614 " hist trigger\t- If set, event hits are aggregated into a hash table\n"
5615 "\t Format: hist:keys=<field1[,field2,...]>\n"
5616 "\t [:values=<field1[,field2,...]>]\n"
5617 "\t [:sort=<field1[,field2,...]>]\n"
5618 "\t [:size=#entries]\n"
5619 "\t [:pause][:continue][:clear]\n"
5620 "\t [:name=histname1]\n"
5621 "\t [:<handler>.<action>]\n"
5622 "\t [if <filter>]\n\n"
5623 "\t Note, special fields can be used as well:\n"
5624 "\t common_timestamp - to record current timestamp\n"
5625 "\t common_cpu - to record the CPU the event happened on\n"
5626 "\n"
5627 "\t When a matching event is hit, an entry is added to a hash\n"
5628 "\t table using the key(s) and value(s) named, and the value of a\n"
5629 "\t sum called 'hitcount' is incremented. Keys and values\n"
5630 "\t correspond to fields in the event's format description. Keys\n"
5631 "\t can be any field, or the special string 'stacktrace'.\n"
5632 "\t Compound keys consisting of up to two fields can be specified\n"
5633 "\t by the 'keys' keyword. Values must correspond to numeric\n"
5634 "\t fields. Sort keys consisting of up to two fields can be\n"
5635 "\t specified using the 'sort' keyword. The sort direction can\n"
5636 "\t be modified by appending '.descending' or '.ascending' to a\n"
5637 "\t sort field. The 'size' parameter can be used to specify more\n"
5638 "\t or fewer than the default 2048 entries for the hashtable size.\n"
5639 "\t If a hist trigger is given a name using the 'name' parameter,\n"
5640 "\t its histogram data will be shared with other triggers of the\n"
5641 "\t same name, and trigger hits will update this common data.\n\n"
5642 "\t Reading the 'hist' file for the event will dump the hash\n"
5643 "\t table in its entirety to stdout. If there are multiple hist\n"
5644 "\t triggers attached to an event, there will be a table for each\n"
5645 "\t trigger in the output. The table displayed for a named\n"
5646 "\t trigger will be the same as any other instance having the\n"
5647 "\t same name. The default format used to display a given field\n"
5648 "\t can be modified by appending any of the following modifiers\n"
5649 "\t to the field name, as applicable:\n\n"
5650 "\t .hex display a number as a hex value\n"
5651 "\t .sym display an address as a symbol\n"
5652 "\t .sym-offset display an address as a symbol and offset\n"
5653 "\t .execname display a common_pid as a program name\n"
5654 "\t .syscall display a syscall id as a syscall name\n"
5655 "\t .log2 display log2 value rather than raw number\n"
5656 "\t .usecs display a common_timestamp in microseconds\n\n"
5657 "\t The 'pause' parameter can be used to pause an existing hist\n"
5658 "\t trigger or to start a hist trigger but not log any events\n"
5659 "\t until told to do so. 'continue' can be used to start or\n"
5660 "\t restart a paused hist trigger.\n\n"
5661 "\t The 'clear' parameter will clear the contents of a running\n"
5662 "\t hist trigger and leave its current paused/active state\n"
5663 "\t unchanged.\n\n"
5664 "\t The enable_hist and disable_hist triggers can be used to\n"
5665 "\t have one event conditionally start and stop another event's\n"
5666 "\t already-attached hist trigger. The syntax is analogous to\n"
5667 "\t the enable_event and disable_event triggers.\n\n"
5668 "\t Hist trigger handlers and actions are executed whenever a\n"
5669 "\t a histogram entry is added or updated. They take the form:\n\n"
5670 "\t <handler>.<action>\n\n"
5671 "\t The available handlers are:\n\n"
5672 "\t onmatch(matching.event) - invoke on addition or update\n"
5673 "\t onmax(var) - invoke if var exceeds current max\n"
5674 "\t onchange(var) - invoke action if var changes\n\n"
5675 "\t The available actions are:\n\n"
5676 "\t trace(<synthetic_event>,param list) - generate synthetic event\n"
5677 "\t save(field,...) - save current event fields\n"
5678#ifdef CONFIG_TRACER_SNAPSHOT
5679 "\t snapshot() - snapshot the trace buffer\n\n"
5680#endif
5681#ifdef CONFIG_SYNTH_EVENTS
5682 " events/synthetic_events\t- Create/append/remove/show synthetic events\n"
5683 "\t Write into this file to define/undefine new synthetic events.\n"
5684 "\t example: echo 'myevent u64 lat; char name[]' >> synthetic_events\n"
5685#endif
5686#endif
5687;
5688
5689static ssize_t
5690tracing_readme_read(struct file *filp, char __user *ubuf,
5691 size_t cnt, loff_t *ppos)
5692{
5693 return simple_read_from_buffer(ubuf, cnt, ppos,
5694 readme_msg, strlen(readme_msg));
5695}
5696
5697static const struct file_operations tracing_readme_fops = {
5698 .open = tracing_open_generic,
5699 .read = tracing_readme_read,
5700 .llseek = generic_file_llseek,
5701};
5702
5703static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
5704{
5705 int pid = ++(*pos);
5706
5707 return trace_find_tgid_ptr(pid);
5708}
5709
5710static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
5711{
5712 int pid = *pos;
5713
5714 return trace_find_tgid_ptr(pid);
5715}
5716
5717static void saved_tgids_stop(struct seq_file *m, void *v)
5718{
5719}
5720
5721static int saved_tgids_show(struct seq_file *m, void *v)
5722{
5723 int *entry = (int *)v;
5724 int pid = entry - tgid_map;
5725 int tgid = *entry;
5726
5727 if (tgid == 0)
5728 return SEQ_SKIP;
5729
5730 seq_printf(m, "%d %d\n", pid, tgid);
5731 return 0;
5732}
5733
5734static const struct seq_operations tracing_saved_tgids_seq_ops = {
5735 .start = saved_tgids_start,
5736 .stop = saved_tgids_stop,
5737 .next = saved_tgids_next,
5738 .show = saved_tgids_show,
5739};
5740
5741static int tracing_saved_tgids_open(struct inode *inode, struct file *filp)
5742{
5743 int ret;
5744
5745 ret = tracing_check_open_get_tr(NULL);
5746 if (ret)
5747 return ret;
5748
5749 return seq_open(filp, &tracing_saved_tgids_seq_ops);
5750}
5751
5752
5753static const struct file_operations tracing_saved_tgids_fops = {
5754 .open = tracing_saved_tgids_open,
5755 .read = seq_read,
5756 .llseek = seq_lseek,
5757 .release = seq_release,
5758};
5759
5760static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
5761{
5762 unsigned int *ptr = v;
5763
5764 if (*pos || m->count)
5765 ptr++;
5766
5767 (*pos)++;
5768
5769 for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
5770 ptr++) {
5771 if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
5772 continue;
5773
5774 return ptr;
5775 }
5776
5777 return NULL;
5778}
5779
5780static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
5781{
5782 void *v;
5783 loff_t l = 0;
5784
5785 preempt_disable();
5786 arch_spin_lock(&trace_cmdline_lock);
5787
5788 v = &savedcmd->map_cmdline_to_pid[0];
5789 while (l <= *pos) {
5790 v = saved_cmdlines_next(m, v, &l);
5791 if (!v)
5792 return NULL;
5793 }
5794
5795 return v;
5796}
5797
5798static void saved_cmdlines_stop(struct seq_file *m, void *v)
5799{
5800 arch_spin_unlock(&trace_cmdline_lock);
5801 preempt_enable();
5802}
5803
5804static int saved_cmdlines_show(struct seq_file *m, void *v)
5805{
5806 char buf[TASK_COMM_LEN];
5807 unsigned int *pid = v;
5808
5809 __trace_find_cmdline(*pid, buf);
5810 seq_printf(m, "%d %s\n", *pid, buf);
5811 return 0;
5812}
5813
5814static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
5815 .start = saved_cmdlines_start,
5816 .next = saved_cmdlines_next,
5817 .stop = saved_cmdlines_stop,
5818 .show = saved_cmdlines_show,
5819};
5820
5821static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
5822{
5823 int ret;
5824
5825 ret = tracing_check_open_get_tr(NULL);
5826 if (ret)
5827 return ret;
5828
5829 return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
5830}
5831
5832static const struct file_operations tracing_saved_cmdlines_fops = {
5833 .open = tracing_saved_cmdlines_open,
5834 .read = seq_read,
5835 .llseek = seq_lseek,
5836 .release = seq_release,
5837};
5838
5839static ssize_t
5840tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
5841 size_t cnt, loff_t *ppos)
5842{
5843 char buf[64];
5844 int r;
5845
5846 arch_spin_lock(&trace_cmdline_lock);
5847 r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
5848 arch_spin_unlock(&trace_cmdline_lock);
5849
5850 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5851}
5852
5853static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
5854{
5855 kfree(s->saved_cmdlines);
5856 kfree(s->map_cmdline_to_pid);
5857 kfree(s);
5858}
5859
5860static int tracing_resize_saved_cmdlines(unsigned int val)
5861{
5862 struct saved_cmdlines_buffer *s, *savedcmd_temp;
5863
5864 s = kmalloc(sizeof(*s), GFP_KERNEL);
5865 if (!s)
5866 return -ENOMEM;
5867
5868 if (allocate_cmdlines_buffer(val, s) < 0) {
5869 kfree(s);
5870 return -ENOMEM;
5871 }
5872
5873 arch_spin_lock(&trace_cmdline_lock);
5874 savedcmd_temp = savedcmd;
5875 savedcmd = s;
5876 arch_spin_unlock(&trace_cmdline_lock);
5877 free_saved_cmdlines_buffer(savedcmd_temp);
5878
5879 return 0;
5880}
5881
5882static ssize_t
5883tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
5884 size_t cnt, loff_t *ppos)
5885{
5886 unsigned long val;
5887 int ret;
5888
5889 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5890 if (ret)
5891 return ret;
5892
5893 /* must have at least 1 entry or less than PID_MAX_DEFAULT */
5894 if (!val || val > PID_MAX_DEFAULT)
5895 return -EINVAL;
5896
5897 ret = tracing_resize_saved_cmdlines((unsigned int)val);
5898 if (ret < 0)
5899 return ret;
5900
5901 *ppos += cnt;
5902
5903 return cnt;
5904}
5905
5906static const struct file_operations tracing_saved_cmdlines_size_fops = {
5907 .open = tracing_open_generic,
5908 .read = tracing_saved_cmdlines_size_read,
5909 .write = tracing_saved_cmdlines_size_write,
5910};
5911
5912#ifdef CONFIG_TRACE_EVAL_MAP_FILE
5913static union trace_eval_map_item *
5914update_eval_map(union trace_eval_map_item *ptr)
5915{
5916 if (!ptr->map.eval_string) {
5917 if (ptr->tail.next) {
5918 ptr = ptr->tail.next;
5919 /* Set ptr to the next real item (skip head) */
5920 ptr++;
5921 } else
5922 return NULL;
5923 }
5924 return ptr;
5925}
5926
5927static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
5928{
5929 union trace_eval_map_item *ptr = v;
5930
5931 /*
5932 * Paranoid! If ptr points to end, we don't want to increment past it.
5933 * This really should never happen.
5934 */
5935 (*pos)++;
5936 ptr = update_eval_map(ptr);
5937 if (WARN_ON_ONCE(!ptr))
5938 return NULL;
5939
5940 ptr++;
5941 ptr = update_eval_map(ptr);
5942
5943 return ptr;
5944}
5945
5946static void *eval_map_start(struct seq_file *m, loff_t *pos)
5947{
5948 union trace_eval_map_item *v;
5949 loff_t l = 0;
5950
5951 mutex_lock(&trace_eval_mutex);
5952
5953 v = trace_eval_maps;
5954 if (v)
5955 v++;
5956
5957 while (v && l < *pos) {
5958 v = eval_map_next(m, v, &l);
5959 }
5960
5961 return v;
5962}
5963
5964static void eval_map_stop(struct seq_file *m, void *v)
5965{
5966 mutex_unlock(&trace_eval_mutex);
5967}
5968
5969static int eval_map_show(struct seq_file *m, void *v)
5970{
5971 union trace_eval_map_item *ptr = v;
5972
5973 seq_printf(m, "%s %ld (%s)\n",
5974 ptr->map.eval_string, ptr->map.eval_value,
5975 ptr->map.system);
5976
5977 return 0;
5978}
5979
5980static const struct seq_operations tracing_eval_map_seq_ops = {
5981 .start = eval_map_start,
5982 .next = eval_map_next,
5983 .stop = eval_map_stop,
5984 .show = eval_map_show,
5985};
5986
5987static int tracing_eval_map_open(struct inode *inode, struct file *filp)
5988{
5989 int ret;
5990
5991 ret = tracing_check_open_get_tr(NULL);
5992 if (ret)
5993 return ret;
5994
5995 return seq_open(filp, &tracing_eval_map_seq_ops);
5996}
5997
5998static const struct file_operations tracing_eval_map_fops = {
5999 .open = tracing_eval_map_open,
6000 .read = seq_read,
6001 .llseek = seq_lseek,
6002 .release = seq_release,
6003};
6004
6005static inline union trace_eval_map_item *
6006trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
6007{
6008 /* Return tail of array given the head */
6009 return ptr + ptr->head.length + 1;
6010}
6011
6012static void
6013trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
6014 int len)
6015{
6016 struct trace_eval_map **stop;
6017 struct trace_eval_map **map;
6018 union trace_eval_map_item *map_array;
6019 union trace_eval_map_item *ptr;
6020
6021 stop = start + len;
6022
6023 /*
6024 * The trace_eval_maps contains the map plus a head and tail item,
6025 * where the head holds the module and length of array, and the
6026 * tail holds a pointer to the next list.
6027 */
6028 map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
6029 if (!map_array) {
6030 pr_warn("Unable to allocate trace eval mapping\n");
6031 return;
6032 }
6033
6034 mutex_lock(&trace_eval_mutex);
6035
6036 if (!trace_eval_maps)
6037 trace_eval_maps = map_array;
6038 else {
6039 ptr = trace_eval_maps;
6040 for (;;) {
6041 ptr = trace_eval_jmp_to_tail(ptr);
6042 if (!ptr->tail.next)
6043 break;
6044 ptr = ptr->tail.next;
6045
6046 }
6047 ptr->tail.next = map_array;
6048 }
6049 map_array->head.mod = mod;
6050 map_array->head.length = len;
6051 map_array++;
6052
6053 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
6054 map_array->map = **map;
6055 map_array++;
6056 }
6057 memset(map_array, 0, sizeof(*map_array));
6058
6059 mutex_unlock(&trace_eval_mutex);
6060}
6061
6062static void trace_create_eval_file(struct dentry *d_tracer)
6063{
6064 trace_create_file("eval_map", 0444, d_tracer,
6065 NULL, &tracing_eval_map_fops);
6066}
6067
6068#else /* CONFIG_TRACE_EVAL_MAP_FILE */
6069static inline void trace_create_eval_file(struct dentry *d_tracer) { }
6070static inline void trace_insert_eval_map_file(struct module *mod,
6071 struct trace_eval_map **start, int len) { }
6072#endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
6073
6074static void trace_insert_eval_map(struct module *mod,
6075 struct trace_eval_map **start, int len)
6076{
6077 struct trace_eval_map **map;
6078
6079 if (len <= 0)
6080 return;
6081
6082 map = start;
6083
6084 trace_event_eval_update(map, len);
6085
6086 trace_insert_eval_map_file(mod, start, len);
6087}
6088
6089static ssize_t
6090tracing_set_trace_read(struct file *filp, char __user *ubuf,
6091 size_t cnt, loff_t *ppos)
6092{
6093 struct trace_array *tr = filp->private_data;
6094 char buf[MAX_TRACER_SIZE+2];
6095 int r;
6096
6097 mutex_lock(&trace_types_lock);
6098 r = sprintf(buf, "%s\n", tr->current_trace->name);
6099 mutex_unlock(&trace_types_lock);
6100
6101 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6102}
6103
6104int tracer_init(struct tracer *t, struct trace_array *tr)
6105{
6106 tracing_reset_online_cpus(&tr->array_buffer);
6107 return t->init(tr);
6108}
6109
6110static void set_buffer_entries(struct array_buffer *buf, unsigned long val)
6111{
6112 int cpu;
6113
6114 for_each_tracing_cpu(cpu)
6115 per_cpu_ptr(buf->data, cpu)->entries = val;
6116}
6117
6118#ifdef CONFIG_TRACER_MAX_TRACE
6119/* resize @tr's buffer to the size of @size_tr's entries */
6120static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
6121 struct array_buffer *size_buf, int cpu_id)
6122{
6123 int cpu, ret = 0;
6124
6125 if (cpu_id == RING_BUFFER_ALL_CPUS) {
6126 for_each_tracing_cpu(cpu) {
6127 ret = ring_buffer_resize(trace_buf->buffer,
6128 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
6129 if (ret < 0)
6130 break;
6131 per_cpu_ptr(trace_buf->data, cpu)->entries =
6132 per_cpu_ptr(size_buf->data, cpu)->entries;
6133 }
6134 } else {
6135 ret = ring_buffer_resize(trace_buf->buffer,
6136 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
6137 if (ret == 0)
6138 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
6139 per_cpu_ptr(size_buf->data, cpu_id)->entries;
6140 }
6141
6142 return ret;
6143}
6144#endif /* CONFIG_TRACER_MAX_TRACE */
6145
6146static int __tracing_resize_ring_buffer(struct trace_array *tr,
6147 unsigned long size, int cpu)
6148{
6149 int ret;
6150
6151 /*
6152 * If kernel or user changes the size of the ring buffer
6153 * we use the size that was given, and we can forget about
6154 * expanding it later.
6155 */
6156 ring_buffer_expanded = true;
6157
6158 /* May be called before buffers are initialized */
6159 if (!tr->array_buffer.buffer)
6160 return 0;
6161
6162 ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu);
6163 if (ret < 0)
6164 return ret;
6165
6166#ifdef CONFIG_TRACER_MAX_TRACE
6167 if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
6168 !tr->current_trace->use_max_tr)
6169 goto out;
6170
6171 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
6172 if (ret < 0) {
6173 int r = resize_buffer_duplicate_size(&tr->array_buffer,
6174 &tr->array_buffer, cpu);
6175 if (r < 0) {
6176 /*
6177 * AARGH! We are left with different
6178 * size max buffer!!!!
6179 * The max buffer is our "snapshot" buffer.
6180 * When a tracer needs a snapshot (one of the
6181 * latency tracers), it swaps the max buffer
6182 * with the saved snap shot. We succeeded to
6183 * update the size of the main buffer, but failed to
6184 * update the size of the max buffer. But when we tried
6185 * to reset the main buffer to the original size, we
6186 * failed there too. This is very unlikely to
6187 * happen, but if it does, warn and kill all
6188 * tracing.
6189 */
6190 WARN_ON(1);
6191 tracing_disabled = 1;
6192 }
6193 return ret;
6194 }
6195
6196 if (cpu == RING_BUFFER_ALL_CPUS)
6197 set_buffer_entries(&tr->max_buffer, size);
6198 else
6199 per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
6200
6201 out:
6202#endif /* CONFIG_TRACER_MAX_TRACE */
6203
6204 if (cpu == RING_BUFFER_ALL_CPUS)
6205 set_buffer_entries(&tr->array_buffer, size);
6206 else
6207 per_cpu_ptr(tr->array_buffer.data, cpu)->entries = size;
6208
6209 return ret;
6210}
6211
6212ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
6213 unsigned long size, int cpu_id)
6214{
6215 int ret;
6216
6217 mutex_lock(&trace_types_lock);
6218
6219 if (cpu_id != RING_BUFFER_ALL_CPUS) {
6220 /* make sure, this cpu is enabled in the mask */
6221 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
6222 ret = -EINVAL;
6223 goto out;
6224 }
6225 }
6226
6227 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
6228 if (ret < 0)
6229 ret = -ENOMEM;
6230
6231out:
6232 mutex_unlock(&trace_types_lock);
6233
6234 return ret;
6235}
6236
6237
6238/**
6239 * tracing_update_buffers - used by tracing facility to expand ring buffers
6240 *
6241 * To save on memory when the tracing is never used on a system with it
6242 * configured in. The ring buffers are set to a minimum size. But once
6243 * a user starts to use the tracing facility, then they need to grow
6244 * to their default size.
6245 *
6246 * This function is to be called when a tracer is about to be used.
6247 */
6248int tracing_update_buffers(void)
6249{
6250 int ret = 0;
6251
6252 mutex_lock(&trace_types_lock);
6253 if (!ring_buffer_expanded)
6254 ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
6255 RING_BUFFER_ALL_CPUS);
6256 mutex_unlock(&trace_types_lock);
6257
6258 return ret;
6259}
6260
6261struct trace_option_dentry;
6262
6263static void
6264create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
6265
6266/*
6267 * Used to clear out the tracer before deletion of an instance.
6268 * Must have trace_types_lock held.
6269 */
6270static void tracing_set_nop(struct trace_array *tr)
6271{
6272 if (tr->current_trace == &nop_trace)
6273 return;
6274
6275 tr->current_trace->enabled--;
6276
6277 if (tr->current_trace->reset)
6278 tr->current_trace->reset(tr);
6279
6280 tr->current_trace = &nop_trace;
6281}
6282
6283static void add_tracer_options(struct trace_array *tr, struct tracer *t)
6284{
6285 /* Only enable if the directory has been created already. */
6286 if (!tr->dir)
6287 return;
6288
6289 create_trace_option_files(tr, t);
6290}
6291
6292int tracing_set_tracer(struct trace_array *tr, const char *buf)
6293{
6294 struct tracer *t;
6295#ifdef CONFIG_TRACER_MAX_TRACE
6296 bool had_max_tr;
6297#endif
6298 int ret = 0;
6299
6300 mutex_lock(&trace_types_lock);
6301
6302 if (!ring_buffer_expanded) {
6303 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6304 RING_BUFFER_ALL_CPUS);
6305 if (ret < 0)
6306 goto out;
6307 ret = 0;
6308 }
6309
6310 for (t = trace_types; t; t = t->next) {
6311 if (strcmp(t->name, buf) == 0)
6312 break;
6313 }
6314 if (!t) {
6315 ret = -EINVAL;
6316 goto out;
6317 }
6318 if (t == tr->current_trace)
6319 goto out;
6320
6321#ifdef CONFIG_TRACER_SNAPSHOT
6322 if (t->use_max_tr) {
6323 arch_spin_lock(&tr->max_lock);
6324 if (tr->cond_snapshot)
6325 ret = -EBUSY;
6326 arch_spin_unlock(&tr->max_lock);
6327 if (ret)
6328 goto out;
6329 }
6330#endif
6331 /* Some tracers won't work on kernel command line */
6332 if (system_state < SYSTEM_RUNNING && t->noboot) {
6333 pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
6334 t->name);
6335 goto out;
6336 }
6337
6338 /* Some tracers are only allowed for the top level buffer */
6339 if (!trace_ok_for_array(t, tr)) {
6340 ret = -EINVAL;
6341 goto out;
6342 }
6343
6344 /* If trace pipe files are being read, we can't change the tracer */
6345 if (tr->trace_ref) {
6346 ret = -EBUSY;
6347 goto out;
6348 }
6349
6350 trace_branch_disable();
6351
6352 tr->current_trace->enabled--;
6353
6354 if (tr->current_trace->reset)
6355 tr->current_trace->reset(tr);
6356
6357 /* Current trace needs to be nop_trace before synchronize_rcu */
6358 tr->current_trace = &nop_trace;
6359
6360#ifdef CONFIG_TRACER_MAX_TRACE
6361 had_max_tr = tr->allocated_snapshot;
6362
6363 if (had_max_tr && !t->use_max_tr) {
6364 /*
6365 * We need to make sure that the update_max_tr sees that
6366 * current_trace changed to nop_trace to keep it from
6367 * swapping the buffers after we resize it.
6368 * The update_max_tr is called from interrupts disabled
6369 * so a synchronized_sched() is sufficient.
6370 */
6371 synchronize_rcu();
6372 free_snapshot(tr);
6373 }
6374#endif
6375
6376#ifdef CONFIG_TRACER_MAX_TRACE
6377 if (t->use_max_tr && !had_max_tr) {
6378 ret = tracing_alloc_snapshot_instance(tr);
6379 if (ret < 0)
6380 goto out;
6381 }
6382#endif
6383
6384 if (t->init) {
6385 ret = tracer_init(t, tr);
6386 if (ret)
6387 goto out;
6388 }
6389
6390 tr->current_trace = t;
6391 tr->current_trace->enabled++;
6392 trace_branch_enable(tr);
6393 out:
6394 mutex_unlock(&trace_types_lock);
6395
6396 return ret;
6397}
6398
6399static ssize_t
6400tracing_set_trace_write(struct file *filp, const char __user *ubuf,
6401 size_t cnt, loff_t *ppos)
6402{
6403 struct trace_array *tr = filp->private_data;
6404 char buf[MAX_TRACER_SIZE+1];
6405 int i;
6406 size_t ret;
6407 int err;
6408
6409 ret = cnt;
6410
6411 if (cnt > MAX_TRACER_SIZE)
6412 cnt = MAX_TRACER_SIZE;
6413
6414 if (copy_from_user(buf, ubuf, cnt))
6415 return -EFAULT;
6416
6417 buf[cnt] = 0;
6418
6419 /* strip ending whitespace. */
6420 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
6421 buf[i] = 0;
6422
6423 err = tracing_set_tracer(tr, buf);
6424 if (err)
6425 return err;
6426
6427 *ppos += ret;
6428
6429 return ret;
6430}
6431
6432static ssize_t
6433tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
6434 size_t cnt, loff_t *ppos)
6435{
6436 char buf[64];
6437 int r;
6438
6439 r = snprintf(buf, sizeof(buf), "%ld\n",
6440 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
6441 if (r > sizeof(buf))
6442 r = sizeof(buf);
6443 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6444}
6445
6446static ssize_t
6447tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
6448 size_t cnt, loff_t *ppos)
6449{
6450 unsigned long val;
6451 int ret;
6452
6453 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6454 if (ret)
6455 return ret;
6456
6457 *ptr = val * 1000;
6458
6459 return cnt;
6460}
6461
6462static ssize_t
6463tracing_thresh_read(struct file *filp, char __user *ubuf,
6464 size_t cnt, loff_t *ppos)
6465{
6466 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
6467}
6468
6469static ssize_t
6470tracing_thresh_write(struct file *filp, const char __user *ubuf,
6471 size_t cnt, loff_t *ppos)
6472{
6473 struct trace_array *tr = filp->private_data;
6474 int ret;
6475
6476 mutex_lock(&trace_types_lock);
6477 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
6478 if (ret < 0)
6479 goto out;
6480
6481 if (tr->current_trace->update_thresh) {
6482 ret = tr->current_trace->update_thresh(tr);
6483 if (ret < 0)
6484 goto out;
6485 }
6486
6487 ret = cnt;
6488out:
6489 mutex_unlock(&trace_types_lock);
6490
6491 return ret;
6492}
6493
6494#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
6495
6496static ssize_t
6497tracing_max_lat_read(struct file *filp, char __user *ubuf,
6498 size_t cnt, loff_t *ppos)
6499{
6500 return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
6501}
6502
6503static ssize_t
6504tracing_max_lat_write(struct file *filp, const char __user *ubuf,
6505 size_t cnt, loff_t *ppos)
6506{
6507 return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
6508}
6509
6510#endif
6511
6512static int tracing_open_pipe(struct inode *inode, struct file *filp)
6513{
6514 struct trace_array *tr = inode->i_private;
6515 struct trace_iterator *iter;
6516 int ret;
6517
6518 ret = tracing_check_open_get_tr(tr);
6519 if (ret)
6520 return ret;
6521
6522 mutex_lock(&trace_types_lock);
6523
6524 /* create a buffer to store the information to pass to userspace */
6525 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
6526 if (!iter) {
6527 ret = -ENOMEM;
6528 __trace_array_put(tr);
6529 goto out;
6530 }
6531
6532 trace_seq_init(&iter->seq);
6533 iter->trace = tr->current_trace;
6534
6535 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
6536 ret = -ENOMEM;
6537 goto fail;
6538 }
6539
6540 /* trace pipe does not show start of buffer */
6541 cpumask_setall(iter->started);
6542
6543 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
6544 iter->iter_flags |= TRACE_FILE_LAT_FMT;
6545
6546 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
6547 if (trace_clocks[tr->clock_id].in_ns)
6548 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
6549
6550 iter->tr = tr;
6551 iter->array_buffer = &tr->array_buffer;
6552 iter->cpu_file = tracing_get_cpu(inode);
6553 mutex_init(&iter->mutex);
6554 filp->private_data = iter;
6555
6556 if (iter->trace->pipe_open)
6557 iter->trace->pipe_open(iter);
6558
6559 nonseekable_open(inode, filp);
6560
6561 tr->trace_ref++;
6562out:
6563 mutex_unlock(&trace_types_lock);
6564 return ret;
6565
6566fail:
6567 kfree(iter);
6568 __trace_array_put(tr);
6569 mutex_unlock(&trace_types_lock);
6570 return ret;
6571}
6572
6573static int tracing_release_pipe(struct inode *inode, struct file *file)
6574{
6575 struct trace_iterator *iter = file->private_data;
6576 struct trace_array *tr = inode->i_private;
6577
6578 mutex_lock(&trace_types_lock);
6579
6580 tr->trace_ref--;
6581
6582 if (iter->trace->pipe_close)
6583 iter->trace->pipe_close(iter);
6584
6585 mutex_unlock(&trace_types_lock);
6586
6587 free_cpumask_var(iter->started);
6588 mutex_destroy(&iter->mutex);
6589 kfree(iter);
6590
6591 trace_array_put(tr);
6592
6593 return 0;
6594}
6595
6596static __poll_t
6597trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
6598{
6599 struct trace_array *tr = iter->tr;
6600
6601 /* Iterators are static, they should be filled or empty */
6602 if (trace_buffer_iter(iter, iter->cpu_file))
6603 return EPOLLIN | EPOLLRDNORM;
6604
6605 if (tr->trace_flags & TRACE_ITER_BLOCK)
6606 /*
6607 * Always select as readable when in blocking mode
6608 */
6609 return EPOLLIN | EPOLLRDNORM;
6610 else
6611 return ring_buffer_poll_wait(iter->array_buffer->buffer, iter->cpu_file,
6612 filp, poll_table);
6613}
6614
6615static __poll_t
6616tracing_poll_pipe(struct file *filp, poll_table *poll_table)
6617{
6618 struct trace_iterator *iter = filp->private_data;
6619
6620 return trace_poll(iter, filp, poll_table);
6621}
6622
6623/* Must be called with iter->mutex held. */
6624static int tracing_wait_pipe(struct file *filp)
6625{
6626 struct trace_iterator *iter = filp->private_data;
6627 int ret;
6628
6629 while (trace_empty(iter)) {
6630
6631 if ((filp->f_flags & O_NONBLOCK)) {
6632 return -EAGAIN;
6633 }
6634
6635 /*
6636 * We block until we read something and tracing is disabled.
6637 * We still block if tracing is disabled, but we have never
6638 * read anything. This allows a user to cat this file, and
6639 * then enable tracing. But after we have read something,
6640 * we give an EOF when tracing is again disabled.
6641 *
6642 * iter->pos will be 0 if we haven't read anything.
6643 */
6644 if (!tracer_tracing_is_on(iter->tr) && iter->pos)
6645 break;
6646
6647 mutex_unlock(&iter->mutex);
6648
6649 ret = wait_on_pipe(iter, 0);
6650
6651 mutex_lock(&iter->mutex);
6652
6653 if (ret)
6654 return ret;
6655 }
6656
6657 return 1;
6658}
6659
6660/*
6661 * Consumer reader.
6662 */
6663static ssize_t
6664tracing_read_pipe(struct file *filp, char __user *ubuf,
6665 size_t cnt, loff_t *ppos)
6666{
6667 struct trace_iterator *iter = filp->private_data;
6668 ssize_t sret;
6669
6670 /*
6671 * Avoid more than one consumer on a single file descriptor
6672 * This is just a matter of traces coherency, the ring buffer itself
6673 * is protected.
6674 */
6675 mutex_lock(&iter->mutex);
6676
6677 /* return any leftover data */
6678 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6679 if (sret != -EBUSY)
6680 goto out;
6681
6682 trace_seq_init(&iter->seq);
6683
6684 if (iter->trace->read) {
6685 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
6686 if (sret)
6687 goto out;
6688 }
6689
6690waitagain:
6691 sret = tracing_wait_pipe(filp);
6692 if (sret <= 0)
6693 goto out;
6694
6695 /* stop when tracing is finished */
6696 if (trace_empty(iter)) {
6697 sret = 0;
6698 goto out;
6699 }
6700
6701 if (cnt >= PAGE_SIZE)
6702 cnt = PAGE_SIZE - 1;
6703
6704 /* reset all but tr, trace, and overruns */
6705 memset(&iter->seq, 0,
6706 sizeof(struct trace_iterator) -
6707 offsetof(struct trace_iterator, seq));
6708 cpumask_clear(iter->started);
6709 trace_seq_init(&iter->seq);
6710 iter->pos = -1;
6711
6712 trace_event_read_lock();
6713 trace_access_lock(iter->cpu_file);
6714 while (trace_find_next_entry_inc(iter) != NULL) {
6715 enum print_line_t ret;
6716 int save_len = iter->seq.seq.len;
6717
6718 ret = print_trace_line(iter);
6719 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6720 /* don't print partial lines */
6721 iter->seq.seq.len = save_len;
6722 break;
6723 }
6724 if (ret != TRACE_TYPE_NO_CONSUME)
6725 trace_consume(iter);
6726
6727 if (trace_seq_used(&iter->seq) >= cnt)
6728 break;
6729
6730 /*
6731 * Setting the full flag means we reached the trace_seq buffer
6732 * size and we should leave by partial output condition above.
6733 * One of the trace_seq_* functions is not used properly.
6734 */
6735 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
6736 iter->ent->type);
6737 }
6738 trace_access_unlock(iter->cpu_file);
6739 trace_event_read_unlock();
6740
6741 /* Now copy what we have to the user */
6742 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6743 if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
6744 trace_seq_init(&iter->seq);
6745
6746 /*
6747 * If there was nothing to send to user, in spite of consuming trace
6748 * entries, go back to wait for more entries.
6749 */
6750 if (sret == -EBUSY)
6751 goto waitagain;
6752
6753out:
6754 mutex_unlock(&iter->mutex);
6755
6756 return sret;
6757}
6758
6759static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
6760 unsigned int idx)
6761{
6762 __free_page(spd->pages[idx]);
6763}
6764
6765static size_t
6766tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
6767{
6768 size_t count;
6769 int save_len;
6770 int ret;
6771
6772 /* Seq buffer is page-sized, exactly what we need. */
6773 for (;;) {
6774 save_len = iter->seq.seq.len;
6775 ret = print_trace_line(iter);
6776
6777 if (trace_seq_has_overflowed(&iter->seq)) {
6778 iter->seq.seq.len = save_len;
6779 break;
6780 }
6781
6782 /*
6783 * This should not be hit, because it should only
6784 * be set if the iter->seq overflowed. But check it
6785 * anyway to be safe.
6786 */
6787 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6788 iter->seq.seq.len = save_len;
6789 break;
6790 }
6791
6792 count = trace_seq_used(&iter->seq) - save_len;
6793 if (rem < count) {
6794 rem = 0;
6795 iter->seq.seq.len = save_len;
6796 break;
6797 }
6798
6799 if (ret != TRACE_TYPE_NO_CONSUME)
6800 trace_consume(iter);
6801 rem -= count;
6802 if (!trace_find_next_entry_inc(iter)) {
6803 rem = 0;
6804 iter->ent = NULL;
6805 break;
6806 }
6807 }
6808
6809 return rem;
6810}
6811
6812static ssize_t tracing_splice_read_pipe(struct file *filp,
6813 loff_t *ppos,
6814 struct pipe_inode_info *pipe,
6815 size_t len,
6816 unsigned int flags)
6817{
6818 struct page *pages_def[PIPE_DEF_BUFFERS];
6819 struct partial_page partial_def[PIPE_DEF_BUFFERS];
6820 struct trace_iterator *iter = filp->private_data;
6821 struct splice_pipe_desc spd = {
6822 .pages = pages_def,
6823 .partial = partial_def,
6824 .nr_pages = 0, /* This gets updated below. */
6825 .nr_pages_max = PIPE_DEF_BUFFERS,
6826 .ops = &default_pipe_buf_ops,
6827 .spd_release = tracing_spd_release_pipe,
6828 };
6829 ssize_t ret;
6830 size_t rem;
6831 unsigned int i;
6832
6833 if (splice_grow_spd(pipe, &spd))
6834 return -ENOMEM;
6835
6836 mutex_lock(&iter->mutex);
6837
6838 if (iter->trace->splice_read) {
6839 ret = iter->trace->splice_read(iter, filp,
6840 ppos, pipe, len, flags);
6841 if (ret)
6842 goto out_err;
6843 }
6844
6845 ret = tracing_wait_pipe(filp);
6846 if (ret <= 0)
6847 goto out_err;
6848
6849 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
6850 ret = -EFAULT;
6851 goto out_err;
6852 }
6853
6854 trace_event_read_lock();
6855 trace_access_lock(iter->cpu_file);
6856
6857 /* Fill as many pages as possible. */
6858 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
6859 spd.pages[i] = alloc_page(GFP_KERNEL);
6860 if (!spd.pages[i])
6861 break;
6862
6863 rem = tracing_fill_pipe_page(rem, iter);
6864
6865 /* Copy the data into the page, so we can start over. */
6866 ret = trace_seq_to_buffer(&iter->seq,
6867 page_address(spd.pages[i]),
6868 trace_seq_used(&iter->seq));
6869 if (ret < 0) {
6870 __free_page(spd.pages[i]);
6871 break;
6872 }
6873 spd.partial[i].offset = 0;
6874 spd.partial[i].len = trace_seq_used(&iter->seq);
6875
6876 trace_seq_init(&iter->seq);
6877 }
6878
6879 trace_access_unlock(iter->cpu_file);
6880 trace_event_read_unlock();
6881 mutex_unlock(&iter->mutex);
6882
6883 spd.nr_pages = i;
6884
6885 if (i)
6886 ret = splice_to_pipe(pipe, &spd);
6887 else
6888 ret = 0;
6889out:
6890 splice_shrink_spd(&spd);
6891 return ret;
6892
6893out_err:
6894 mutex_unlock(&iter->mutex);
6895 goto out;
6896}
6897
6898static ssize_t
6899tracing_entries_read(struct file *filp, char __user *ubuf,
6900 size_t cnt, loff_t *ppos)
6901{
6902 struct inode *inode = file_inode(filp);
6903 struct trace_array *tr = inode->i_private;
6904 int cpu = tracing_get_cpu(inode);
6905 char buf[64];
6906 int r = 0;
6907 ssize_t ret;
6908
6909 mutex_lock(&trace_types_lock);
6910
6911 if (cpu == RING_BUFFER_ALL_CPUS) {
6912 int cpu, buf_size_same;
6913 unsigned long size;
6914
6915 size = 0;
6916 buf_size_same = 1;
6917 /* check if all cpu sizes are same */
6918 for_each_tracing_cpu(cpu) {
6919 /* fill in the size from first enabled cpu */
6920 if (size == 0)
6921 size = per_cpu_ptr(tr->array_buffer.data, cpu)->entries;
6922 if (size != per_cpu_ptr(tr->array_buffer.data, cpu)->entries) {
6923 buf_size_same = 0;
6924 break;
6925 }
6926 }
6927
6928 if (buf_size_same) {
6929 if (!ring_buffer_expanded)
6930 r = sprintf(buf, "%lu (expanded: %lu)\n",
6931 size >> 10,
6932 trace_buf_size >> 10);
6933 else
6934 r = sprintf(buf, "%lu\n", size >> 10);
6935 } else
6936 r = sprintf(buf, "X\n");
6937 } else
6938 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10);
6939
6940 mutex_unlock(&trace_types_lock);
6941
6942 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6943 return ret;
6944}
6945
6946static ssize_t
6947tracing_entries_write(struct file *filp, const char __user *ubuf,
6948 size_t cnt, loff_t *ppos)
6949{
6950 struct inode *inode = file_inode(filp);
6951 struct trace_array *tr = inode->i_private;
6952 unsigned long val;
6953 int ret;
6954
6955 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6956 if (ret)
6957 return ret;
6958
6959 /* must have at least 1 entry */
6960 if (!val)
6961 return -EINVAL;
6962
6963 /* value is in KB */
6964 val <<= 10;
6965 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
6966 if (ret < 0)
6967 return ret;
6968
6969 *ppos += cnt;
6970
6971 return cnt;
6972}
6973
6974static ssize_t
6975tracing_total_entries_read(struct file *filp, char __user *ubuf,
6976 size_t cnt, loff_t *ppos)
6977{
6978 struct trace_array *tr = filp->private_data;
6979 char buf[64];
6980 int r, cpu;
6981 unsigned long size = 0, expanded_size = 0;
6982
6983 mutex_lock(&trace_types_lock);
6984 for_each_tracing_cpu(cpu) {
6985 size += per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10;
6986 if (!ring_buffer_expanded)
6987 expanded_size += trace_buf_size >> 10;
6988 }
6989 if (ring_buffer_expanded)
6990 r = sprintf(buf, "%lu\n", size);
6991 else
6992 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
6993 mutex_unlock(&trace_types_lock);
6994
6995 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6996}
6997
6998static ssize_t
6999tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
7000 size_t cnt, loff_t *ppos)
7001{
7002 /*
7003 * There is no need to read what the user has written, this function
7004 * is just to make sure that there is no error when "echo" is used
7005 */
7006
7007 *ppos += cnt;
7008
7009 return cnt;
7010}
7011
7012static int
7013tracing_free_buffer_release(struct inode *inode, struct file *filp)
7014{
7015 struct trace_array *tr = inode->i_private;
7016
7017 /* disable tracing ? */
7018 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
7019 tracer_tracing_off(tr);
7020 /* resize the ring buffer to 0 */
7021 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
7022
7023 trace_array_put(tr);
7024
7025 return 0;
7026}
7027
7028static ssize_t
7029tracing_mark_write(struct file *filp, const char __user *ubuf,
7030 size_t cnt, loff_t *fpos)
7031{
7032 struct trace_array *tr = filp->private_data;
7033 struct ring_buffer_event *event;
7034 enum event_trigger_type tt = ETT_NONE;
7035 struct trace_buffer *buffer;
7036 struct print_entry *entry;
7037 ssize_t written;
7038 int size;
7039 int len;
7040
7041/* Used in tracing_mark_raw_write() as well */
7042#define FAULTED_STR "<faulted>"
7043#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */
7044
7045 if (tracing_disabled)
7046 return -EINVAL;
7047
7048 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7049 return -EINVAL;
7050
7051 if (cnt > TRACE_BUF_SIZE)
7052 cnt = TRACE_BUF_SIZE;
7053
7054 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
7055
7056 size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */
7057
7058 /* If less than "<faulted>", then make sure we can still add that */
7059 if (cnt < FAULTED_SIZE)
7060 size += FAULTED_SIZE - cnt;
7061
7062 buffer = tr->array_buffer.buffer;
7063 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
7064 tracing_gen_ctx());
7065 if (unlikely(!event))
7066 /* Ring buffer disabled, return as if not open for write */
7067 return -EBADF;
7068
7069 entry = ring_buffer_event_data(event);
7070 entry->ip = _THIS_IP_;
7071
7072 len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
7073 if (len) {
7074 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7075 cnt = FAULTED_SIZE;
7076 written = -EFAULT;
7077 } else
7078 written = cnt;
7079
7080 if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
7081 /* do not add \n before testing triggers, but add \0 */
7082 entry->buf[cnt] = '\0';
7083 tt = event_triggers_call(tr->trace_marker_file, buffer, entry, event);
7084 }
7085
7086 if (entry->buf[cnt - 1] != '\n') {
7087 entry->buf[cnt] = '\n';
7088 entry->buf[cnt + 1] = '\0';
7089 } else
7090 entry->buf[cnt] = '\0';
7091
7092 if (static_branch_unlikely(&trace_marker_exports_enabled))
7093 ftrace_exports(event, TRACE_EXPORT_MARKER);
7094 __buffer_unlock_commit(buffer, event);
7095
7096 if (tt)
7097 event_triggers_post_call(tr->trace_marker_file, tt);
7098
7099 if (written > 0)
7100 *fpos += written;
7101
7102 return written;
7103}
7104
7105/* Limit it for now to 3K (including tag) */
7106#define RAW_DATA_MAX_SIZE (1024*3)
7107
7108static ssize_t
7109tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
7110 size_t cnt, loff_t *fpos)
7111{
7112 struct trace_array *tr = filp->private_data;
7113 struct ring_buffer_event *event;
7114 struct trace_buffer *buffer;
7115 struct raw_data_entry *entry;
7116 ssize_t written;
7117 int size;
7118 int len;
7119
7120#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
7121
7122 if (tracing_disabled)
7123 return -EINVAL;
7124
7125 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7126 return -EINVAL;
7127
7128 /* The marker must at least have a tag id */
7129 if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE)
7130 return -EINVAL;
7131
7132 if (cnt > TRACE_BUF_SIZE)
7133 cnt = TRACE_BUF_SIZE;
7134
7135 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
7136
7137 size = sizeof(*entry) + cnt;
7138 if (cnt < FAULT_SIZE_ID)
7139 size += FAULT_SIZE_ID - cnt;
7140
7141 buffer = tr->array_buffer.buffer;
7142 event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
7143 tracing_gen_ctx());
7144 if (!event)
7145 /* Ring buffer disabled, return as if not open for write */
7146 return -EBADF;
7147
7148 entry = ring_buffer_event_data(event);
7149
7150 len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
7151 if (len) {
7152 entry->id = -1;
7153 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7154 written = -EFAULT;
7155 } else
7156 written = cnt;
7157
7158 __buffer_unlock_commit(buffer, event);
7159
7160 if (written > 0)
7161 *fpos += written;
7162
7163 return written;
7164}
7165
7166static int tracing_clock_show(struct seq_file *m, void *v)
7167{
7168 struct trace_array *tr = m->private;
7169 int i;
7170
7171 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
7172 seq_printf(m,
7173 "%s%s%s%s", i ? " " : "",
7174 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
7175 i == tr->clock_id ? "]" : "");
7176 seq_putc(m, '\n');
7177
7178 return 0;
7179}
7180
7181int tracing_set_clock(struct trace_array *tr, const char *clockstr)
7182{
7183 int i;
7184
7185 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
7186 if (strcmp(trace_clocks[i].name, clockstr) == 0)
7187 break;
7188 }
7189 if (i == ARRAY_SIZE(trace_clocks))
7190 return -EINVAL;
7191
7192 mutex_lock(&trace_types_lock);
7193
7194 tr->clock_id = i;
7195
7196 ring_buffer_set_clock(tr->array_buffer.buffer, trace_clocks[i].func);
7197
7198 /*
7199 * New clock may not be consistent with the previous clock.
7200 * Reset the buffer so that it doesn't have incomparable timestamps.
7201 */
7202 tracing_reset_online_cpus(&tr->array_buffer);
7203
7204#ifdef CONFIG_TRACER_MAX_TRACE
7205 if (tr->max_buffer.buffer)
7206 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
7207 tracing_reset_online_cpus(&tr->max_buffer);
7208#endif
7209
7210 mutex_unlock(&trace_types_lock);
7211
7212 return 0;
7213}
7214
7215static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
7216 size_t cnt, loff_t *fpos)
7217{
7218 struct seq_file *m = filp->private_data;
7219 struct trace_array *tr = m->private;
7220 char buf[64];
7221 const char *clockstr;
7222 int ret;
7223
7224 if (cnt >= sizeof(buf))
7225 return -EINVAL;
7226
7227 if (copy_from_user(buf, ubuf, cnt))
7228 return -EFAULT;
7229
7230 buf[cnt] = 0;
7231
7232 clockstr = strstrip(buf);
7233
7234 ret = tracing_set_clock(tr, clockstr);
7235 if (ret)
7236 return ret;
7237
7238 *fpos += cnt;
7239
7240 return cnt;
7241}
7242
7243static int tracing_clock_open(struct inode *inode, struct file *file)
7244{
7245 struct trace_array *tr = inode->i_private;
7246 int ret;
7247
7248 ret = tracing_check_open_get_tr(tr);
7249 if (ret)
7250 return ret;
7251
7252 ret = single_open(file, tracing_clock_show, inode->i_private);
7253 if (ret < 0)
7254 trace_array_put(tr);
7255
7256 return ret;
7257}
7258
7259static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
7260{
7261 struct trace_array *tr = m->private;
7262
7263 mutex_lock(&trace_types_lock);
7264
7265 if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer))
7266 seq_puts(m, "delta [absolute]\n");
7267 else
7268 seq_puts(m, "[delta] absolute\n");
7269
7270 mutex_unlock(&trace_types_lock);
7271
7272 return 0;
7273}
7274
7275static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
7276{
7277 struct trace_array *tr = inode->i_private;
7278 int ret;
7279
7280 ret = tracing_check_open_get_tr(tr);
7281 if (ret)
7282 return ret;
7283
7284 ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
7285 if (ret < 0)
7286 trace_array_put(tr);
7287
7288 return ret;
7289}
7290
7291u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe)
7292{
7293 if (rbe == this_cpu_read(trace_buffered_event))
7294 return ring_buffer_time_stamp(buffer);
7295
7296 return ring_buffer_event_time_stamp(buffer, rbe);
7297}
7298
7299/*
7300 * Set or disable using the per CPU trace_buffer_event when possible.
7301 */
7302int tracing_set_filter_buffering(struct trace_array *tr, bool set)
7303{
7304 int ret = 0;
7305
7306 mutex_lock(&trace_types_lock);
7307
7308 if (set && tr->no_filter_buffering_ref++)
7309 goto out;
7310
7311 if (!set) {
7312 if (WARN_ON_ONCE(!tr->no_filter_buffering_ref)) {
7313 ret = -EINVAL;
7314 goto out;
7315 }
7316
7317 --tr->no_filter_buffering_ref;
7318 }
7319 out:
7320 mutex_unlock(&trace_types_lock);
7321
7322 return ret;
7323}
7324
7325struct ftrace_buffer_info {
7326 struct trace_iterator iter;
7327 void *spare;
7328 unsigned int spare_cpu;
7329 unsigned int read;
7330};
7331
7332#ifdef CONFIG_TRACER_SNAPSHOT
7333static int tracing_snapshot_open(struct inode *inode, struct file *file)
7334{
7335 struct trace_array *tr = inode->i_private;
7336 struct trace_iterator *iter;
7337 struct seq_file *m;
7338 int ret;
7339
7340 ret = tracing_check_open_get_tr(tr);
7341 if (ret)
7342 return ret;
7343
7344 if (file->f_mode & FMODE_READ) {
7345 iter = __tracing_open(inode, file, true);
7346 if (IS_ERR(iter))
7347 ret = PTR_ERR(iter);
7348 } else {
7349 /* Writes still need the seq_file to hold the private data */
7350 ret = -ENOMEM;
7351 m = kzalloc(sizeof(*m), GFP_KERNEL);
7352 if (!m)
7353 goto out;
7354 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
7355 if (!iter) {
7356 kfree(m);
7357 goto out;
7358 }
7359 ret = 0;
7360
7361 iter->tr = tr;
7362 iter->array_buffer = &tr->max_buffer;
7363 iter->cpu_file = tracing_get_cpu(inode);
7364 m->private = iter;
7365 file->private_data = m;
7366 }
7367out:
7368 if (ret < 0)
7369 trace_array_put(tr);
7370
7371 return ret;
7372}
7373
7374static ssize_t
7375tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
7376 loff_t *ppos)
7377{
7378 struct seq_file *m = filp->private_data;
7379 struct trace_iterator *iter = m->private;
7380 struct trace_array *tr = iter->tr;
7381 unsigned long val;
7382 int ret;
7383
7384 ret = tracing_update_buffers();
7385 if (ret < 0)
7386 return ret;
7387
7388 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7389 if (ret)
7390 return ret;
7391
7392 mutex_lock(&trace_types_lock);
7393
7394 if (tr->current_trace->use_max_tr) {
7395 ret = -EBUSY;
7396 goto out;
7397 }
7398
7399 arch_spin_lock(&tr->max_lock);
7400 if (tr->cond_snapshot)
7401 ret = -EBUSY;
7402 arch_spin_unlock(&tr->max_lock);
7403 if (ret)
7404 goto out;
7405
7406 switch (val) {
7407 case 0:
7408 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7409 ret = -EINVAL;
7410 break;
7411 }
7412 if (tr->allocated_snapshot)
7413 free_snapshot(tr);
7414 break;
7415 case 1:
7416/* Only allow per-cpu swap if the ring buffer supports it */
7417#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
7418 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7419 ret = -EINVAL;
7420 break;
7421 }
7422#endif
7423 if (tr->allocated_snapshot)
7424 ret = resize_buffer_duplicate_size(&tr->max_buffer,
7425 &tr->array_buffer, iter->cpu_file);
7426 else
7427 ret = tracing_alloc_snapshot_instance(tr);
7428 if (ret < 0)
7429 break;
7430 local_irq_disable();
7431 /* Now, we're going to swap */
7432 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
7433 update_max_tr(tr, current, smp_processor_id(), NULL);
7434 else
7435 update_max_tr_single(tr, current, iter->cpu_file);
7436 local_irq_enable();
7437 break;
7438 default:
7439 if (tr->allocated_snapshot) {
7440 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
7441 tracing_reset_online_cpus(&tr->max_buffer);
7442 else
7443 tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
7444 }
7445 break;
7446 }
7447
7448 if (ret >= 0) {
7449 *ppos += cnt;
7450 ret = cnt;
7451 }
7452out:
7453 mutex_unlock(&trace_types_lock);
7454 return ret;
7455}
7456
7457static int tracing_snapshot_release(struct inode *inode, struct file *file)
7458{
7459 struct seq_file *m = file->private_data;
7460 int ret;
7461
7462 ret = tracing_release(inode, file);
7463
7464 if (file->f_mode & FMODE_READ)
7465 return ret;
7466
7467 /* If write only, the seq_file is just a stub */
7468 if (m)
7469 kfree(m->private);
7470 kfree(m);
7471
7472 return 0;
7473}
7474
7475static int tracing_buffers_open(struct inode *inode, struct file *filp);
7476static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
7477 size_t count, loff_t *ppos);
7478static int tracing_buffers_release(struct inode *inode, struct file *file);
7479static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
7480 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
7481
7482static int snapshot_raw_open(struct inode *inode, struct file *filp)
7483{
7484 struct ftrace_buffer_info *info;
7485 int ret;
7486
7487 /* The following checks for tracefs lockdown */
7488 ret = tracing_buffers_open(inode, filp);
7489 if (ret < 0)
7490 return ret;
7491
7492 info = filp->private_data;
7493
7494 if (info->iter.trace->use_max_tr) {
7495 tracing_buffers_release(inode, filp);
7496 return -EBUSY;
7497 }
7498
7499 info->iter.snapshot = true;
7500 info->iter.array_buffer = &info->iter.tr->max_buffer;
7501
7502 return ret;
7503}
7504
7505#endif /* CONFIG_TRACER_SNAPSHOT */
7506
7507
7508static const struct file_operations tracing_thresh_fops = {
7509 .open = tracing_open_generic,
7510 .read = tracing_thresh_read,
7511 .write = tracing_thresh_write,
7512 .llseek = generic_file_llseek,
7513};
7514
7515#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
7516static const struct file_operations tracing_max_lat_fops = {
7517 .open = tracing_open_generic,
7518 .read = tracing_max_lat_read,
7519 .write = tracing_max_lat_write,
7520 .llseek = generic_file_llseek,
7521};
7522#endif
7523
7524static const struct file_operations set_tracer_fops = {
7525 .open = tracing_open_generic,
7526 .read = tracing_set_trace_read,
7527 .write = tracing_set_trace_write,
7528 .llseek = generic_file_llseek,
7529};
7530
7531static const struct file_operations tracing_pipe_fops = {
7532 .open = tracing_open_pipe,
7533 .poll = tracing_poll_pipe,
7534 .read = tracing_read_pipe,
7535 .splice_read = tracing_splice_read_pipe,
7536 .release = tracing_release_pipe,
7537 .llseek = no_llseek,
7538};
7539
7540static const struct file_operations tracing_entries_fops = {
7541 .open = tracing_open_generic_tr,
7542 .read = tracing_entries_read,
7543 .write = tracing_entries_write,
7544 .llseek = generic_file_llseek,
7545 .release = tracing_release_generic_tr,
7546};
7547
7548static const struct file_operations tracing_total_entries_fops = {
7549 .open = tracing_open_generic_tr,
7550 .read = tracing_total_entries_read,
7551 .llseek = generic_file_llseek,
7552 .release = tracing_release_generic_tr,
7553};
7554
7555static const struct file_operations tracing_free_buffer_fops = {
7556 .open = tracing_open_generic_tr,
7557 .write = tracing_free_buffer_write,
7558 .release = tracing_free_buffer_release,
7559};
7560
7561static const struct file_operations tracing_mark_fops = {
7562 .open = tracing_open_generic_tr,
7563 .write = tracing_mark_write,
7564 .llseek = generic_file_llseek,
7565 .release = tracing_release_generic_tr,
7566};
7567
7568static const struct file_operations tracing_mark_raw_fops = {
7569 .open = tracing_open_generic_tr,
7570 .write = tracing_mark_raw_write,
7571 .llseek = generic_file_llseek,
7572 .release = tracing_release_generic_tr,
7573};
7574
7575static const struct file_operations trace_clock_fops = {
7576 .open = tracing_clock_open,
7577 .read = seq_read,
7578 .llseek = seq_lseek,
7579 .release = tracing_single_release_tr,
7580 .write = tracing_clock_write,
7581};
7582
7583static const struct file_operations trace_time_stamp_mode_fops = {
7584 .open = tracing_time_stamp_mode_open,
7585 .read = seq_read,
7586 .llseek = seq_lseek,
7587 .release = tracing_single_release_tr,
7588};
7589
7590#ifdef CONFIG_TRACER_SNAPSHOT
7591static const struct file_operations snapshot_fops = {
7592 .open = tracing_snapshot_open,
7593 .read = seq_read,
7594 .write = tracing_snapshot_write,
7595 .llseek = tracing_lseek,
7596 .release = tracing_snapshot_release,
7597};
7598
7599static const struct file_operations snapshot_raw_fops = {
7600 .open = snapshot_raw_open,
7601 .read = tracing_buffers_read,
7602 .release = tracing_buffers_release,
7603 .splice_read = tracing_buffers_splice_read,
7604 .llseek = no_llseek,
7605};
7606
7607#endif /* CONFIG_TRACER_SNAPSHOT */
7608
7609/*
7610 * trace_min_max_write - Write a u64 value to a trace_min_max_param struct
7611 * @filp: The active open file structure
7612 * @ubuf: The userspace provided buffer to read value into
7613 * @cnt: The maximum number of bytes to read
7614 * @ppos: The current "file" position
7615 *
7616 * This function implements the write interface for a struct trace_min_max_param.
7617 * The filp->private_data must point to a trace_min_max_param structure that
7618 * defines where to write the value, the min and the max acceptable values,
7619 * and a lock to protect the write.
7620 */
7621static ssize_t
7622trace_min_max_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos)
7623{
7624 struct trace_min_max_param *param = filp->private_data;
7625 u64 val;
7626 int err;
7627
7628 if (!param)
7629 return -EFAULT;
7630
7631 err = kstrtoull_from_user(ubuf, cnt, 10, &val);
7632 if (err)
7633 return err;
7634
7635 if (param->lock)
7636 mutex_lock(param->lock);
7637
7638 if (param->min && val < *param->min)
7639 err = -EINVAL;
7640
7641 if (param->max && val > *param->max)
7642 err = -EINVAL;
7643
7644 if (!err)
7645 *param->val = val;
7646
7647 if (param->lock)
7648 mutex_unlock(param->lock);
7649
7650 if (err)
7651 return err;
7652
7653 return cnt;
7654}
7655
7656/*
7657 * trace_min_max_read - Read a u64 value from a trace_min_max_param struct
7658 * @filp: The active open file structure
7659 * @ubuf: The userspace provided buffer to read value into
7660 * @cnt: The maximum number of bytes to read
7661 * @ppos: The current "file" position
7662 *
7663 * This function implements the read interface for a struct trace_min_max_param.
7664 * The filp->private_data must point to a trace_min_max_param struct with valid
7665 * data.
7666 */
7667static ssize_t
7668trace_min_max_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
7669{
7670 struct trace_min_max_param *param = filp->private_data;
7671 char buf[U64_STR_SIZE];
7672 int len;
7673 u64 val;
7674
7675 if (!param)
7676 return -EFAULT;
7677
7678 val = *param->val;
7679
7680 if (cnt > sizeof(buf))
7681 cnt = sizeof(buf);
7682
7683 len = snprintf(buf, sizeof(buf), "%llu\n", val);
7684
7685 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
7686}
7687
7688const struct file_operations trace_min_max_fops = {
7689 .open = tracing_open_generic,
7690 .read = trace_min_max_read,
7691 .write = trace_min_max_write,
7692};
7693
7694#define TRACING_LOG_ERRS_MAX 8
7695#define TRACING_LOG_LOC_MAX 128
7696
7697#define CMD_PREFIX " Command: "
7698
7699struct err_info {
7700 const char **errs; /* ptr to loc-specific array of err strings */
7701 u8 type; /* index into errs -> specific err string */
7702 u8 pos; /* MAX_FILTER_STR_VAL = 256 */
7703 u64 ts;
7704};
7705
7706struct tracing_log_err {
7707 struct list_head list;
7708 struct err_info info;
7709 char loc[TRACING_LOG_LOC_MAX]; /* err location */
7710 char cmd[MAX_FILTER_STR_VAL]; /* what caused err */
7711};
7712
7713static DEFINE_MUTEX(tracing_err_log_lock);
7714
7715static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr)
7716{
7717 struct tracing_log_err *err;
7718
7719 if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
7720 err = kzalloc(sizeof(*err), GFP_KERNEL);
7721 if (!err)
7722 err = ERR_PTR(-ENOMEM);
7723 tr->n_err_log_entries++;
7724
7725 return err;
7726 }
7727
7728 err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
7729 list_del(&err->list);
7730
7731 return err;
7732}
7733
7734/**
7735 * err_pos - find the position of a string within a command for error careting
7736 * @cmd: The tracing command that caused the error
7737 * @str: The string to position the caret at within @cmd
7738 *
7739 * Finds the position of the first occurrence of @str within @cmd. The
7740 * return value can be passed to tracing_log_err() for caret placement
7741 * within @cmd.
7742 *
7743 * Returns the index within @cmd of the first occurrence of @str or 0
7744 * if @str was not found.
7745 */
7746unsigned int err_pos(char *cmd, const char *str)
7747{
7748 char *found;
7749
7750 if (WARN_ON(!strlen(cmd)))
7751 return 0;
7752
7753 found = strstr(cmd, str);
7754 if (found)
7755 return found - cmd;
7756
7757 return 0;
7758}
7759
7760/**
7761 * tracing_log_err - write an error to the tracing error log
7762 * @tr: The associated trace array for the error (NULL for top level array)
7763 * @loc: A string describing where the error occurred
7764 * @cmd: The tracing command that caused the error
7765 * @errs: The array of loc-specific static error strings
7766 * @type: The index into errs[], which produces the specific static err string
7767 * @pos: The position the caret should be placed in the cmd
7768 *
7769 * Writes an error into tracing/error_log of the form:
7770 *
7771 * <loc>: error: <text>
7772 * Command: <cmd>
7773 * ^
7774 *
7775 * tracing/error_log is a small log file containing the last
7776 * TRACING_LOG_ERRS_MAX errors (8). Memory for errors isn't allocated
7777 * unless there has been a tracing error, and the error log can be
7778 * cleared and have its memory freed by writing the empty string in
7779 * truncation mode to it i.e. echo > tracing/error_log.
7780 *
7781 * NOTE: the @errs array along with the @type param are used to
7782 * produce a static error string - this string is not copied and saved
7783 * when the error is logged - only a pointer to it is saved. See
7784 * existing callers for examples of how static strings are typically
7785 * defined for use with tracing_log_err().
7786 */
7787void tracing_log_err(struct trace_array *tr,
7788 const char *loc, const char *cmd,
7789 const char **errs, u8 type, u8 pos)
7790{
7791 struct tracing_log_err *err;
7792
7793 if (!tr)
7794 tr = &global_trace;
7795
7796 mutex_lock(&tracing_err_log_lock);
7797 err = get_tracing_log_err(tr);
7798 if (PTR_ERR(err) == -ENOMEM) {
7799 mutex_unlock(&tracing_err_log_lock);
7800 return;
7801 }
7802
7803 snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
7804 snprintf(err->cmd, MAX_FILTER_STR_VAL,"\n" CMD_PREFIX "%s\n", cmd);
7805
7806 err->info.errs = errs;
7807 err->info.type = type;
7808 err->info.pos = pos;
7809 err->info.ts = local_clock();
7810
7811 list_add_tail(&err->list, &tr->err_log);
7812 mutex_unlock(&tracing_err_log_lock);
7813}
7814
7815static void clear_tracing_err_log(struct trace_array *tr)
7816{
7817 struct tracing_log_err *err, *next;
7818
7819 mutex_lock(&tracing_err_log_lock);
7820 list_for_each_entry_safe(err, next, &tr->err_log, list) {
7821 list_del(&err->list);
7822 kfree(err);
7823 }
7824
7825 tr->n_err_log_entries = 0;
7826 mutex_unlock(&tracing_err_log_lock);
7827}
7828
7829static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
7830{
7831 struct trace_array *tr = m->private;
7832
7833 mutex_lock(&tracing_err_log_lock);
7834
7835 return seq_list_start(&tr->err_log, *pos);
7836}
7837
7838static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos)
7839{
7840 struct trace_array *tr = m->private;
7841
7842 return seq_list_next(v, &tr->err_log, pos);
7843}
7844
7845static void tracing_err_log_seq_stop(struct seq_file *m, void *v)
7846{
7847 mutex_unlock(&tracing_err_log_lock);
7848}
7849
7850static void tracing_err_log_show_pos(struct seq_file *m, u8 pos)
7851{
7852 u8 i;
7853
7854 for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++)
7855 seq_putc(m, ' ');
7856 for (i = 0; i < pos; i++)
7857 seq_putc(m, ' ');
7858 seq_puts(m, "^\n");
7859}
7860
7861static int tracing_err_log_seq_show(struct seq_file *m, void *v)
7862{
7863 struct tracing_log_err *err = v;
7864
7865 if (err) {
7866 const char *err_text = err->info.errs[err->info.type];
7867 u64 sec = err->info.ts;
7868 u32 nsec;
7869
7870 nsec = do_div(sec, NSEC_PER_SEC);
7871 seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000,
7872 err->loc, err_text);
7873 seq_printf(m, "%s", err->cmd);
7874 tracing_err_log_show_pos(m, err->info.pos);
7875 }
7876
7877 return 0;
7878}
7879
7880static const struct seq_operations tracing_err_log_seq_ops = {
7881 .start = tracing_err_log_seq_start,
7882 .next = tracing_err_log_seq_next,
7883 .stop = tracing_err_log_seq_stop,
7884 .show = tracing_err_log_seq_show
7885};
7886
7887static int tracing_err_log_open(struct inode *inode, struct file *file)
7888{
7889 struct trace_array *tr = inode->i_private;
7890 int ret = 0;
7891
7892 ret = tracing_check_open_get_tr(tr);
7893 if (ret)
7894 return ret;
7895
7896 /* If this file was opened for write, then erase contents */
7897 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
7898 clear_tracing_err_log(tr);
7899
7900 if (file->f_mode & FMODE_READ) {
7901 ret = seq_open(file, &tracing_err_log_seq_ops);
7902 if (!ret) {
7903 struct seq_file *m = file->private_data;
7904 m->private = tr;
7905 } else {
7906 trace_array_put(tr);
7907 }
7908 }
7909 return ret;
7910}
7911
7912static ssize_t tracing_err_log_write(struct file *file,
7913 const char __user *buffer,
7914 size_t count, loff_t *ppos)
7915{
7916 return count;
7917}
7918
7919static int tracing_err_log_release(struct inode *inode, struct file *file)
7920{
7921 struct trace_array *tr = inode->i_private;
7922
7923 trace_array_put(tr);
7924
7925 if (file->f_mode & FMODE_READ)
7926 seq_release(inode, file);
7927
7928 return 0;
7929}
7930
7931static const struct file_operations tracing_err_log_fops = {
7932 .open = tracing_err_log_open,
7933 .write = tracing_err_log_write,
7934 .read = seq_read,
7935 .llseek = seq_lseek,
7936 .release = tracing_err_log_release,
7937};
7938
7939static int tracing_buffers_open(struct inode *inode, struct file *filp)
7940{
7941 struct trace_array *tr = inode->i_private;
7942 struct ftrace_buffer_info *info;
7943 int ret;
7944
7945 ret = tracing_check_open_get_tr(tr);
7946 if (ret)
7947 return ret;
7948
7949 info = kvzalloc(sizeof(*info), GFP_KERNEL);
7950 if (!info) {
7951 trace_array_put(tr);
7952 return -ENOMEM;
7953 }
7954
7955 mutex_lock(&trace_types_lock);
7956
7957 info->iter.tr = tr;
7958 info->iter.cpu_file = tracing_get_cpu(inode);
7959 info->iter.trace = tr->current_trace;
7960 info->iter.array_buffer = &tr->array_buffer;
7961 info->spare = NULL;
7962 /* Force reading ring buffer for first read */
7963 info->read = (unsigned int)-1;
7964
7965 filp->private_data = info;
7966
7967 tr->trace_ref++;
7968
7969 mutex_unlock(&trace_types_lock);
7970
7971 ret = nonseekable_open(inode, filp);
7972 if (ret < 0)
7973 trace_array_put(tr);
7974
7975 return ret;
7976}
7977
7978static __poll_t
7979tracing_buffers_poll(struct file *filp, poll_table *poll_table)
7980{
7981 struct ftrace_buffer_info *info = filp->private_data;
7982 struct trace_iterator *iter = &info->iter;
7983
7984 return trace_poll(iter, filp, poll_table);
7985}
7986
7987static ssize_t
7988tracing_buffers_read(struct file *filp, char __user *ubuf,
7989 size_t count, loff_t *ppos)
7990{
7991 struct ftrace_buffer_info *info = filp->private_data;
7992 struct trace_iterator *iter = &info->iter;
7993 ssize_t ret = 0;
7994 ssize_t size;
7995
7996 if (!count)
7997 return 0;
7998
7999#ifdef CONFIG_TRACER_MAX_TRACE
8000 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8001 return -EBUSY;
8002#endif
8003
8004 if (!info->spare) {
8005 info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer,
8006 iter->cpu_file);
8007 if (IS_ERR(info->spare)) {
8008 ret = PTR_ERR(info->spare);
8009 info->spare = NULL;
8010 } else {
8011 info->spare_cpu = iter->cpu_file;
8012 }
8013 }
8014 if (!info->spare)
8015 return ret;
8016
8017 /* Do we have previous read data to read? */
8018 if (info->read < PAGE_SIZE)
8019 goto read;
8020
8021 again:
8022 trace_access_lock(iter->cpu_file);
8023 ret = ring_buffer_read_page(iter->array_buffer->buffer,
8024 &info->spare,
8025 count,
8026 iter->cpu_file, 0);
8027 trace_access_unlock(iter->cpu_file);
8028
8029 if (ret < 0) {
8030 if (trace_empty(iter)) {
8031 if ((filp->f_flags & O_NONBLOCK))
8032 return -EAGAIN;
8033
8034 ret = wait_on_pipe(iter, 0);
8035 if (ret)
8036 return ret;
8037
8038 goto again;
8039 }
8040 return 0;
8041 }
8042
8043 info->read = 0;
8044 read:
8045 size = PAGE_SIZE - info->read;
8046 if (size > count)
8047 size = count;
8048
8049 ret = copy_to_user(ubuf, info->spare + info->read, size);
8050 if (ret == size)
8051 return -EFAULT;
8052
8053 size -= ret;
8054
8055 *ppos += size;
8056 info->read += size;
8057
8058 return size;
8059}
8060
8061static int tracing_buffers_release(struct inode *inode, struct file *file)
8062{
8063 struct ftrace_buffer_info *info = file->private_data;
8064 struct trace_iterator *iter = &info->iter;
8065
8066 mutex_lock(&trace_types_lock);
8067
8068 iter->tr->trace_ref--;
8069
8070 __trace_array_put(iter->tr);
8071
8072 if (info->spare)
8073 ring_buffer_free_read_page(iter->array_buffer->buffer,
8074 info->spare_cpu, info->spare);
8075 kvfree(info);
8076
8077 mutex_unlock(&trace_types_lock);
8078
8079 return 0;
8080}
8081
8082struct buffer_ref {
8083 struct trace_buffer *buffer;
8084 void *page;
8085 int cpu;
8086 refcount_t refcount;
8087};
8088
8089static void buffer_ref_release(struct buffer_ref *ref)
8090{
8091 if (!refcount_dec_and_test(&ref->refcount))
8092 return;
8093 ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
8094 kfree(ref);
8095}
8096
8097static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
8098 struct pipe_buffer *buf)
8099{
8100 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8101
8102 buffer_ref_release(ref);
8103 buf->private = 0;
8104}
8105
8106static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
8107 struct pipe_buffer *buf)
8108{
8109 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8110
8111 if (refcount_read(&ref->refcount) > INT_MAX/2)
8112 return false;
8113
8114 refcount_inc(&ref->refcount);
8115 return true;
8116}
8117
8118/* Pipe buffer operations for a buffer. */
8119static const struct pipe_buf_operations buffer_pipe_buf_ops = {
8120 .release = buffer_pipe_buf_release,
8121 .get = buffer_pipe_buf_get,
8122};
8123
8124/*
8125 * Callback from splice_to_pipe(), if we need to release some pages
8126 * at the end of the spd in case we error'ed out in filling the pipe.
8127 */
8128static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
8129{
8130 struct buffer_ref *ref =
8131 (struct buffer_ref *)spd->partial[i].private;
8132
8133 buffer_ref_release(ref);
8134 spd->partial[i].private = 0;
8135}
8136
8137static ssize_t
8138tracing_buffers_splice_read(struct file *file, loff_t *ppos,
8139 struct pipe_inode_info *pipe, size_t len,
8140 unsigned int flags)
8141{
8142 struct ftrace_buffer_info *info = file->private_data;
8143 struct trace_iterator *iter = &info->iter;
8144 struct partial_page partial_def[PIPE_DEF_BUFFERS];
8145 struct page *pages_def[PIPE_DEF_BUFFERS];
8146 struct splice_pipe_desc spd = {
8147 .pages = pages_def,
8148 .partial = partial_def,
8149 .nr_pages_max = PIPE_DEF_BUFFERS,
8150 .ops = &buffer_pipe_buf_ops,
8151 .spd_release = buffer_spd_release,
8152 };
8153 struct buffer_ref *ref;
8154 int entries, i;
8155 ssize_t ret = 0;
8156
8157#ifdef CONFIG_TRACER_MAX_TRACE
8158 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8159 return -EBUSY;
8160#endif
8161
8162 if (*ppos & (PAGE_SIZE - 1))
8163 return -EINVAL;
8164
8165 if (len & (PAGE_SIZE - 1)) {
8166 if (len < PAGE_SIZE)
8167 return -EINVAL;
8168 len &= PAGE_MASK;
8169 }
8170
8171 if (splice_grow_spd(pipe, &spd))
8172 return -ENOMEM;
8173
8174 again:
8175 trace_access_lock(iter->cpu_file);
8176 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8177
8178 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
8179 struct page *page;
8180 int r;
8181
8182 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
8183 if (!ref) {
8184 ret = -ENOMEM;
8185 break;
8186 }
8187
8188 refcount_set(&ref->refcount, 1);
8189 ref->buffer = iter->array_buffer->buffer;
8190 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
8191 if (IS_ERR(ref->page)) {
8192 ret = PTR_ERR(ref->page);
8193 ref->page = NULL;
8194 kfree(ref);
8195 break;
8196 }
8197 ref->cpu = iter->cpu_file;
8198
8199 r = ring_buffer_read_page(ref->buffer, &ref->page,
8200 len, iter->cpu_file, 1);
8201 if (r < 0) {
8202 ring_buffer_free_read_page(ref->buffer, ref->cpu,
8203 ref->page);
8204 kfree(ref);
8205 break;
8206 }
8207
8208 page = virt_to_page(ref->page);
8209
8210 spd.pages[i] = page;
8211 spd.partial[i].len = PAGE_SIZE;
8212 spd.partial[i].offset = 0;
8213 spd.partial[i].private = (unsigned long)ref;
8214 spd.nr_pages++;
8215 *ppos += PAGE_SIZE;
8216
8217 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8218 }
8219
8220 trace_access_unlock(iter->cpu_file);
8221 spd.nr_pages = i;
8222
8223 /* did we read anything? */
8224 if (!spd.nr_pages) {
8225 if (ret)
8226 goto out;
8227
8228 ret = -EAGAIN;
8229 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
8230 goto out;
8231
8232 ret = wait_on_pipe(iter, iter->tr->buffer_percent);
8233 if (ret)
8234 goto out;
8235
8236 goto again;
8237 }
8238
8239 ret = splice_to_pipe(pipe, &spd);
8240out:
8241 splice_shrink_spd(&spd);
8242
8243 return ret;
8244}
8245
8246static const struct file_operations tracing_buffers_fops = {
8247 .open = tracing_buffers_open,
8248 .read = tracing_buffers_read,
8249 .poll = tracing_buffers_poll,
8250 .release = tracing_buffers_release,
8251 .splice_read = tracing_buffers_splice_read,
8252 .llseek = no_llseek,
8253};
8254
8255static ssize_t
8256tracing_stats_read(struct file *filp, char __user *ubuf,
8257 size_t count, loff_t *ppos)
8258{
8259 struct inode *inode = file_inode(filp);
8260 struct trace_array *tr = inode->i_private;
8261 struct array_buffer *trace_buf = &tr->array_buffer;
8262 int cpu = tracing_get_cpu(inode);
8263 struct trace_seq *s;
8264 unsigned long cnt;
8265 unsigned long long t;
8266 unsigned long usec_rem;
8267
8268 s = kmalloc(sizeof(*s), GFP_KERNEL);
8269 if (!s)
8270 return -ENOMEM;
8271
8272 trace_seq_init(s);
8273
8274 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
8275 trace_seq_printf(s, "entries: %ld\n", cnt);
8276
8277 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
8278 trace_seq_printf(s, "overrun: %ld\n", cnt);
8279
8280 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
8281 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
8282
8283 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
8284 trace_seq_printf(s, "bytes: %ld\n", cnt);
8285
8286 if (trace_clocks[tr->clock_id].in_ns) {
8287 /* local or global for trace_clock */
8288 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8289 usec_rem = do_div(t, USEC_PER_SEC);
8290 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
8291 t, usec_rem);
8292
8293 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer));
8294 usec_rem = do_div(t, USEC_PER_SEC);
8295 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
8296 } else {
8297 /* counter or tsc mode for trace_clock */
8298 trace_seq_printf(s, "oldest event ts: %llu\n",
8299 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8300
8301 trace_seq_printf(s, "now ts: %llu\n",
8302 ring_buffer_time_stamp(trace_buf->buffer));
8303 }
8304
8305 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
8306 trace_seq_printf(s, "dropped events: %ld\n", cnt);
8307
8308 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
8309 trace_seq_printf(s, "read events: %ld\n", cnt);
8310
8311 count = simple_read_from_buffer(ubuf, count, ppos,
8312 s->buffer, trace_seq_used(s));
8313
8314 kfree(s);
8315
8316 return count;
8317}
8318
8319static const struct file_operations tracing_stats_fops = {
8320 .open = tracing_open_generic_tr,
8321 .read = tracing_stats_read,
8322 .llseek = generic_file_llseek,
8323 .release = tracing_release_generic_tr,
8324};
8325
8326#ifdef CONFIG_DYNAMIC_FTRACE
8327
8328static ssize_t
8329tracing_read_dyn_info(struct file *filp, char __user *ubuf,
8330 size_t cnt, loff_t *ppos)
8331{
8332 ssize_t ret;
8333 char *buf;
8334 int r;
8335
8336 /* 256 should be plenty to hold the amount needed */
8337 buf = kmalloc(256, GFP_KERNEL);
8338 if (!buf)
8339 return -ENOMEM;
8340
8341 r = scnprintf(buf, 256, "%ld pages:%ld groups: %ld\n",
8342 ftrace_update_tot_cnt,
8343 ftrace_number_of_pages,
8344 ftrace_number_of_groups);
8345
8346 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8347 kfree(buf);
8348 return ret;
8349}
8350
8351static const struct file_operations tracing_dyn_info_fops = {
8352 .open = tracing_open_generic,
8353 .read = tracing_read_dyn_info,
8354 .llseek = generic_file_llseek,
8355};
8356#endif /* CONFIG_DYNAMIC_FTRACE */
8357
8358#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
8359static void
8360ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
8361 struct trace_array *tr, struct ftrace_probe_ops *ops,
8362 void *data)
8363{
8364 tracing_snapshot_instance(tr);
8365}
8366
8367static void
8368ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
8369 struct trace_array *tr, struct ftrace_probe_ops *ops,
8370 void *data)
8371{
8372 struct ftrace_func_mapper *mapper = data;
8373 long *count = NULL;
8374
8375 if (mapper)
8376 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8377
8378 if (count) {
8379
8380 if (*count <= 0)
8381 return;
8382
8383 (*count)--;
8384 }
8385
8386 tracing_snapshot_instance(tr);
8387}
8388
8389static int
8390ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
8391 struct ftrace_probe_ops *ops, void *data)
8392{
8393 struct ftrace_func_mapper *mapper = data;
8394 long *count = NULL;
8395
8396 seq_printf(m, "%ps:", (void *)ip);
8397
8398 seq_puts(m, "snapshot");
8399
8400 if (mapper)
8401 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8402
8403 if (count)
8404 seq_printf(m, ":count=%ld\n", *count);
8405 else
8406 seq_puts(m, ":unlimited\n");
8407
8408 return 0;
8409}
8410
8411static int
8412ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
8413 unsigned long ip, void *init_data, void **data)
8414{
8415 struct ftrace_func_mapper *mapper = *data;
8416
8417 if (!mapper) {
8418 mapper = allocate_ftrace_func_mapper();
8419 if (!mapper)
8420 return -ENOMEM;
8421 *data = mapper;
8422 }
8423
8424 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
8425}
8426
8427static void
8428ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
8429 unsigned long ip, void *data)
8430{
8431 struct ftrace_func_mapper *mapper = data;
8432
8433 if (!ip) {
8434 if (!mapper)
8435 return;
8436 free_ftrace_func_mapper(mapper, NULL);
8437 return;
8438 }
8439
8440 ftrace_func_mapper_remove_ip(mapper, ip);
8441}
8442
8443static struct ftrace_probe_ops snapshot_probe_ops = {
8444 .func = ftrace_snapshot,
8445 .print = ftrace_snapshot_print,
8446};
8447
8448static struct ftrace_probe_ops snapshot_count_probe_ops = {
8449 .func = ftrace_count_snapshot,
8450 .print = ftrace_snapshot_print,
8451 .init = ftrace_snapshot_init,
8452 .free = ftrace_snapshot_free,
8453};
8454
8455static int
8456ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
8457 char *glob, char *cmd, char *param, int enable)
8458{
8459 struct ftrace_probe_ops *ops;
8460 void *count = (void *)-1;
8461 char *number;
8462 int ret;
8463
8464 if (!tr)
8465 return -ENODEV;
8466
8467 /* hash funcs only work with set_ftrace_filter */
8468 if (!enable)
8469 return -EINVAL;
8470
8471 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
8472
8473 if (glob[0] == '!')
8474 return unregister_ftrace_function_probe_func(glob+1, tr, ops);
8475
8476 if (!param)
8477 goto out_reg;
8478
8479 number = strsep(¶m, ":");
8480
8481 if (!strlen(number))
8482 goto out_reg;
8483
8484 /*
8485 * We use the callback data field (which is a pointer)
8486 * as our counter.
8487 */
8488 ret = kstrtoul(number, 0, (unsigned long *)&count);
8489 if (ret)
8490 return ret;
8491
8492 out_reg:
8493 ret = tracing_alloc_snapshot_instance(tr);
8494 if (ret < 0)
8495 goto out;
8496
8497 ret = register_ftrace_function_probe(glob, tr, ops, count);
8498
8499 out:
8500 return ret < 0 ? ret : 0;
8501}
8502
8503static struct ftrace_func_command ftrace_snapshot_cmd = {
8504 .name = "snapshot",
8505 .func = ftrace_trace_snapshot_callback,
8506};
8507
8508static __init int register_snapshot_cmd(void)
8509{
8510 return register_ftrace_command(&ftrace_snapshot_cmd);
8511}
8512#else
8513static inline __init int register_snapshot_cmd(void) { return 0; }
8514#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
8515
8516static struct dentry *tracing_get_dentry(struct trace_array *tr)
8517{
8518 if (WARN_ON(!tr->dir))
8519 return ERR_PTR(-ENODEV);
8520
8521 /* Top directory uses NULL as the parent */
8522 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
8523 return NULL;
8524
8525 /* All sub buffers have a descriptor */
8526 return tr->dir;
8527}
8528
8529static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
8530{
8531 struct dentry *d_tracer;
8532
8533 if (tr->percpu_dir)
8534 return tr->percpu_dir;
8535
8536 d_tracer = tracing_get_dentry(tr);
8537 if (IS_ERR(d_tracer))
8538 return NULL;
8539
8540 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
8541
8542 MEM_FAIL(!tr->percpu_dir,
8543 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
8544
8545 return tr->percpu_dir;
8546}
8547
8548static struct dentry *
8549trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
8550 void *data, long cpu, const struct file_operations *fops)
8551{
8552 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
8553
8554 if (ret) /* See tracing_get_cpu() */
8555 d_inode(ret)->i_cdev = (void *)(cpu + 1);
8556 return ret;
8557}
8558
8559static void
8560tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
8561{
8562 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
8563 struct dentry *d_cpu;
8564 char cpu_dir[30]; /* 30 characters should be more than enough */
8565
8566 if (!d_percpu)
8567 return;
8568
8569 snprintf(cpu_dir, 30, "cpu%ld", cpu);
8570 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
8571 if (!d_cpu) {
8572 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
8573 return;
8574 }
8575
8576 /* per cpu trace_pipe */
8577 trace_create_cpu_file("trace_pipe", 0444, d_cpu,
8578 tr, cpu, &tracing_pipe_fops);
8579
8580 /* per cpu trace */
8581 trace_create_cpu_file("trace", 0644, d_cpu,
8582 tr, cpu, &tracing_fops);
8583
8584 trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
8585 tr, cpu, &tracing_buffers_fops);
8586
8587 trace_create_cpu_file("stats", 0444, d_cpu,
8588 tr, cpu, &tracing_stats_fops);
8589
8590 trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
8591 tr, cpu, &tracing_entries_fops);
8592
8593#ifdef CONFIG_TRACER_SNAPSHOT
8594 trace_create_cpu_file("snapshot", 0644, d_cpu,
8595 tr, cpu, &snapshot_fops);
8596
8597 trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
8598 tr, cpu, &snapshot_raw_fops);
8599#endif
8600}
8601
8602#ifdef CONFIG_FTRACE_SELFTEST
8603/* Let selftest have access to static functions in this file */
8604#include "trace_selftest.c"
8605#endif
8606
8607static ssize_t
8608trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
8609 loff_t *ppos)
8610{
8611 struct trace_option_dentry *topt = filp->private_data;
8612 char *buf;
8613
8614 if (topt->flags->val & topt->opt->bit)
8615 buf = "1\n";
8616 else
8617 buf = "0\n";
8618
8619 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
8620}
8621
8622static ssize_t
8623trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
8624 loff_t *ppos)
8625{
8626 struct trace_option_dentry *topt = filp->private_data;
8627 unsigned long val;
8628 int ret;
8629
8630 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8631 if (ret)
8632 return ret;
8633
8634 if (val != 0 && val != 1)
8635 return -EINVAL;
8636
8637 if (!!(topt->flags->val & topt->opt->bit) != val) {
8638 mutex_lock(&trace_types_lock);
8639 ret = __set_tracer_option(topt->tr, topt->flags,
8640 topt->opt, !val);
8641 mutex_unlock(&trace_types_lock);
8642 if (ret)
8643 return ret;
8644 }
8645
8646 *ppos += cnt;
8647
8648 return cnt;
8649}
8650
8651
8652static const struct file_operations trace_options_fops = {
8653 .open = tracing_open_generic,
8654 .read = trace_options_read,
8655 .write = trace_options_write,
8656 .llseek = generic_file_llseek,
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, 0644, t_options, topt,
8804 &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, 0644, 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 }
8941 mutex_unlock(&trace_types_lock);
8942 }
8943
8944 (*ppos)++;
8945
8946 return cnt;
8947}
8948
8949static const struct file_operations rb_simple_fops = {
8950 .open = tracing_open_generic_tr,
8951 .read = rb_simple_read,
8952 .write = rb_simple_write,
8953 .release = tracing_release_generic_tr,
8954 .llseek = default_llseek,
8955};
8956
8957static ssize_t
8958buffer_percent_read(struct file *filp, char __user *ubuf,
8959 size_t cnt, loff_t *ppos)
8960{
8961 struct trace_array *tr = filp->private_data;
8962 char buf[64];
8963 int r;
8964
8965 r = tr->buffer_percent;
8966 r = sprintf(buf, "%d\n", r);
8967
8968 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8969}
8970
8971static ssize_t
8972buffer_percent_write(struct file *filp, const char __user *ubuf,
8973 size_t cnt, loff_t *ppos)
8974{
8975 struct trace_array *tr = filp->private_data;
8976 unsigned long val;
8977 int ret;
8978
8979 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8980 if (ret)
8981 return ret;
8982
8983 if (val > 100)
8984 return -EINVAL;
8985
8986 if (!val)
8987 val = 1;
8988
8989 tr->buffer_percent = val;
8990
8991 (*ppos)++;
8992
8993 return cnt;
8994}
8995
8996static const struct file_operations buffer_percent_fops = {
8997 .open = tracing_open_generic_tr,
8998 .read = buffer_percent_read,
8999 .write = buffer_percent_write,
9000 .release = tracing_release_generic_tr,
9001 .llseek = default_llseek,
9002};
9003
9004static struct dentry *trace_instance_dir;
9005
9006static void
9007init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
9008
9009static int
9010allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size)
9011{
9012 enum ring_buffer_flags rb_flags;
9013
9014 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
9015
9016 buf->tr = tr;
9017
9018 buf->buffer = ring_buffer_alloc(size, rb_flags);
9019 if (!buf->buffer)
9020 return -ENOMEM;
9021
9022 buf->data = alloc_percpu(struct trace_array_cpu);
9023 if (!buf->data) {
9024 ring_buffer_free(buf->buffer);
9025 buf->buffer = NULL;
9026 return -ENOMEM;
9027 }
9028
9029 /* Allocate the first page for all buffers */
9030 set_buffer_entries(&tr->array_buffer,
9031 ring_buffer_size(tr->array_buffer.buffer, 0));
9032
9033 return 0;
9034}
9035
9036static int allocate_trace_buffers(struct trace_array *tr, int size)
9037{
9038 int ret;
9039
9040 ret = allocate_trace_buffer(tr, &tr->array_buffer, size);
9041 if (ret)
9042 return ret;
9043
9044#ifdef CONFIG_TRACER_MAX_TRACE
9045 ret = allocate_trace_buffer(tr, &tr->max_buffer,
9046 allocate_snapshot ? size : 1);
9047 if (MEM_FAIL(ret, "Failed to allocate trace buffer\n")) {
9048 ring_buffer_free(tr->array_buffer.buffer);
9049 tr->array_buffer.buffer = NULL;
9050 free_percpu(tr->array_buffer.data);
9051 tr->array_buffer.data = NULL;
9052 return -ENOMEM;
9053 }
9054 tr->allocated_snapshot = allocate_snapshot;
9055
9056 /*
9057 * Only the top level trace array gets its snapshot allocated
9058 * from the kernel command line.
9059 */
9060 allocate_snapshot = false;
9061#endif
9062
9063 return 0;
9064}
9065
9066static void free_trace_buffer(struct array_buffer *buf)
9067{
9068 if (buf->buffer) {
9069 ring_buffer_free(buf->buffer);
9070 buf->buffer = NULL;
9071 free_percpu(buf->data);
9072 buf->data = NULL;
9073 }
9074}
9075
9076static void free_trace_buffers(struct trace_array *tr)
9077{
9078 if (!tr)
9079 return;
9080
9081 free_trace_buffer(&tr->array_buffer);
9082
9083#ifdef CONFIG_TRACER_MAX_TRACE
9084 free_trace_buffer(&tr->max_buffer);
9085#endif
9086}
9087
9088static void init_trace_flags_index(struct trace_array *tr)
9089{
9090 int i;
9091
9092 /* Used by the trace options files */
9093 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
9094 tr->trace_flags_index[i] = i;
9095}
9096
9097static void __update_tracer_options(struct trace_array *tr)
9098{
9099 struct tracer *t;
9100
9101 for (t = trace_types; t; t = t->next)
9102 add_tracer_options(tr, t);
9103}
9104
9105static void update_tracer_options(struct trace_array *tr)
9106{
9107 mutex_lock(&trace_types_lock);
9108 __update_tracer_options(tr);
9109 mutex_unlock(&trace_types_lock);
9110}
9111
9112/* Must have trace_types_lock held */
9113struct trace_array *trace_array_find(const char *instance)
9114{
9115 struct trace_array *tr, *found = NULL;
9116
9117 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9118 if (tr->name && strcmp(tr->name, instance) == 0) {
9119 found = tr;
9120 break;
9121 }
9122 }
9123
9124 return found;
9125}
9126
9127struct trace_array *trace_array_find_get(const char *instance)
9128{
9129 struct trace_array *tr;
9130
9131 mutex_lock(&trace_types_lock);
9132 tr = trace_array_find(instance);
9133 if (tr)
9134 tr->ref++;
9135 mutex_unlock(&trace_types_lock);
9136
9137 return tr;
9138}
9139
9140static int trace_array_create_dir(struct trace_array *tr)
9141{
9142 int ret;
9143
9144 tr->dir = tracefs_create_dir(tr->name, trace_instance_dir);
9145 if (!tr->dir)
9146 return -EINVAL;
9147
9148 ret = event_trace_add_tracer(tr->dir, tr);
9149 if (ret) {
9150 tracefs_remove(tr->dir);
9151 return ret;
9152 }
9153
9154 init_tracer_tracefs(tr, tr->dir);
9155 __update_tracer_options(tr);
9156
9157 return ret;
9158}
9159
9160static struct trace_array *trace_array_create(const char *name)
9161{
9162 struct trace_array *tr;
9163 int ret;
9164
9165 ret = -ENOMEM;
9166 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
9167 if (!tr)
9168 return ERR_PTR(ret);
9169
9170 tr->name = kstrdup(name, GFP_KERNEL);
9171 if (!tr->name)
9172 goto out_free_tr;
9173
9174 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
9175 goto out_free_tr;
9176
9177 tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
9178
9179 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
9180
9181 raw_spin_lock_init(&tr->start_lock);
9182
9183 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
9184
9185 tr->current_trace = &nop_trace;
9186
9187 INIT_LIST_HEAD(&tr->systems);
9188 INIT_LIST_HEAD(&tr->events);
9189 INIT_LIST_HEAD(&tr->hist_vars);
9190 INIT_LIST_HEAD(&tr->err_log);
9191
9192 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
9193 goto out_free_tr;
9194
9195 if (ftrace_allocate_ftrace_ops(tr) < 0)
9196 goto out_free_tr;
9197
9198 ftrace_init_trace_array(tr);
9199
9200 init_trace_flags_index(tr);
9201
9202 if (trace_instance_dir) {
9203 ret = trace_array_create_dir(tr);
9204 if (ret)
9205 goto out_free_tr;
9206 } else
9207 __trace_early_add_events(tr);
9208
9209 list_add(&tr->list, &ftrace_trace_arrays);
9210
9211 tr->ref++;
9212
9213 return tr;
9214
9215 out_free_tr:
9216 ftrace_free_ftrace_ops(tr);
9217 free_trace_buffers(tr);
9218 free_cpumask_var(tr->tracing_cpumask);
9219 kfree(tr->name);
9220 kfree(tr);
9221
9222 return ERR_PTR(ret);
9223}
9224
9225static int instance_mkdir(const char *name)
9226{
9227 struct trace_array *tr;
9228 int ret;
9229
9230 mutex_lock(&event_mutex);
9231 mutex_lock(&trace_types_lock);
9232
9233 ret = -EEXIST;
9234 if (trace_array_find(name))
9235 goto out_unlock;
9236
9237 tr = trace_array_create(name);
9238
9239 ret = PTR_ERR_OR_ZERO(tr);
9240
9241out_unlock:
9242 mutex_unlock(&trace_types_lock);
9243 mutex_unlock(&event_mutex);
9244 return ret;
9245}
9246
9247/**
9248 * trace_array_get_by_name - Create/Lookup a trace array, given its name.
9249 * @name: The name of the trace array to be looked up/created.
9250 *
9251 * Returns pointer to trace array with given name.
9252 * NULL, if it cannot be created.
9253 *
9254 * NOTE: This function increments the reference counter associated with the
9255 * trace array returned. This makes sure it cannot be freed while in use.
9256 * Use trace_array_put() once the trace array is no longer needed.
9257 * If the trace_array is to be freed, trace_array_destroy() needs to
9258 * be called after the trace_array_put(), or simply let user space delete
9259 * it from the tracefs instances directory. But until the
9260 * trace_array_put() is called, user space can not delete it.
9261 *
9262 */
9263struct trace_array *trace_array_get_by_name(const char *name)
9264{
9265 struct trace_array *tr;
9266
9267 mutex_lock(&event_mutex);
9268 mutex_lock(&trace_types_lock);
9269
9270 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9271 if (tr->name && strcmp(tr->name, name) == 0)
9272 goto out_unlock;
9273 }
9274
9275 tr = trace_array_create(name);
9276
9277 if (IS_ERR(tr))
9278 tr = NULL;
9279out_unlock:
9280 if (tr)
9281 tr->ref++;
9282
9283 mutex_unlock(&trace_types_lock);
9284 mutex_unlock(&event_mutex);
9285 return tr;
9286}
9287EXPORT_SYMBOL_GPL(trace_array_get_by_name);
9288
9289static int __remove_instance(struct trace_array *tr)
9290{
9291 int i;
9292
9293 /* Reference counter for a newly created trace array = 1. */
9294 if (tr->ref > 1 || (tr->current_trace && tr->trace_ref))
9295 return -EBUSY;
9296
9297 list_del(&tr->list);
9298
9299 /* Disable all the flags that were enabled coming in */
9300 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
9301 if ((1 << i) & ZEROED_TRACE_FLAGS)
9302 set_tracer_flag(tr, 1 << i, 0);
9303 }
9304
9305 tracing_set_nop(tr);
9306 clear_ftrace_function_probes(tr);
9307 event_trace_del_tracer(tr);
9308 ftrace_clear_pids(tr);
9309 ftrace_destroy_function_files(tr);
9310 tracefs_remove(tr->dir);
9311 free_percpu(tr->last_func_repeats);
9312 free_trace_buffers(tr);
9313
9314 for (i = 0; i < tr->nr_topts; i++) {
9315 kfree(tr->topts[i].topts);
9316 }
9317 kfree(tr->topts);
9318
9319 free_cpumask_var(tr->tracing_cpumask);
9320 kfree(tr->name);
9321 kfree(tr);
9322
9323 return 0;
9324}
9325
9326int trace_array_destroy(struct trace_array *this_tr)
9327{
9328 struct trace_array *tr;
9329 int ret;
9330
9331 if (!this_tr)
9332 return -EINVAL;
9333
9334 mutex_lock(&event_mutex);
9335 mutex_lock(&trace_types_lock);
9336
9337 ret = -ENODEV;
9338
9339 /* Making sure trace array exists before destroying it. */
9340 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9341 if (tr == this_tr) {
9342 ret = __remove_instance(tr);
9343 break;
9344 }
9345 }
9346
9347 mutex_unlock(&trace_types_lock);
9348 mutex_unlock(&event_mutex);
9349
9350 return ret;
9351}
9352EXPORT_SYMBOL_GPL(trace_array_destroy);
9353
9354static int instance_rmdir(const char *name)
9355{
9356 struct trace_array *tr;
9357 int ret;
9358
9359 mutex_lock(&event_mutex);
9360 mutex_lock(&trace_types_lock);
9361
9362 ret = -ENODEV;
9363 tr = trace_array_find(name);
9364 if (tr)
9365 ret = __remove_instance(tr);
9366
9367 mutex_unlock(&trace_types_lock);
9368 mutex_unlock(&event_mutex);
9369
9370 return ret;
9371}
9372
9373static __init void create_trace_instances(struct dentry *d_tracer)
9374{
9375 struct trace_array *tr;
9376
9377 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
9378 instance_mkdir,
9379 instance_rmdir);
9380 if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))
9381 return;
9382
9383 mutex_lock(&event_mutex);
9384 mutex_lock(&trace_types_lock);
9385
9386 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9387 if (!tr->name)
9388 continue;
9389 if (MEM_FAIL(trace_array_create_dir(tr) < 0,
9390 "Failed to create instance directory\n"))
9391 break;
9392 }
9393
9394 mutex_unlock(&trace_types_lock);
9395 mutex_unlock(&event_mutex);
9396}
9397
9398static void
9399init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
9400{
9401 struct trace_event_file *file;
9402 int cpu;
9403
9404 trace_create_file("available_tracers", 0444, d_tracer,
9405 tr, &show_traces_fops);
9406
9407 trace_create_file("current_tracer", 0644, d_tracer,
9408 tr, &set_tracer_fops);
9409
9410 trace_create_file("tracing_cpumask", 0644, d_tracer,
9411 tr, &tracing_cpumask_fops);
9412
9413 trace_create_file("trace_options", 0644, d_tracer,
9414 tr, &tracing_iter_fops);
9415
9416 trace_create_file("trace", 0644, d_tracer,
9417 tr, &tracing_fops);
9418
9419 trace_create_file("trace_pipe", 0444, d_tracer,
9420 tr, &tracing_pipe_fops);
9421
9422 trace_create_file("buffer_size_kb", 0644, d_tracer,
9423 tr, &tracing_entries_fops);
9424
9425 trace_create_file("buffer_total_size_kb", 0444, d_tracer,
9426 tr, &tracing_total_entries_fops);
9427
9428 trace_create_file("free_buffer", 0200, d_tracer,
9429 tr, &tracing_free_buffer_fops);
9430
9431 trace_create_file("trace_marker", 0220, d_tracer,
9432 tr, &tracing_mark_fops);
9433
9434 file = __find_event_file(tr, "ftrace", "print");
9435 if (file && file->dir)
9436 trace_create_file("trigger", 0644, file->dir, file,
9437 &event_trigger_fops);
9438 tr->trace_marker_file = file;
9439
9440 trace_create_file("trace_marker_raw", 0220, d_tracer,
9441 tr, &tracing_mark_raw_fops);
9442
9443 trace_create_file("trace_clock", 0644, d_tracer, tr,
9444 &trace_clock_fops);
9445
9446 trace_create_file("tracing_on", 0644, d_tracer,
9447 tr, &rb_simple_fops);
9448
9449 trace_create_file("timestamp_mode", 0444, d_tracer, tr,
9450 &trace_time_stamp_mode_fops);
9451
9452 tr->buffer_percent = 50;
9453
9454 trace_create_file("buffer_percent", 0444, d_tracer,
9455 tr, &buffer_percent_fops);
9456
9457 create_trace_options_dir(tr);
9458
9459 trace_create_maxlat_file(tr, d_tracer);
9460
9461 if (ftrace_create_function_files(tr, d_tracer))
9462 MEM_FAIL(1, "Could not allocate function filter files");
9463
9464#ifdef CONFIG_TRACER_SNAPSHOT
9465 trace_create_file("snapshot", 0644, d_tracer,
9466 tr, &snapshot_fops);
9467#endif
9468
9469 trace_create_file("error_log", 0644, d_tracer,
9470 tr, &tracing_err_log_fops);
9471
9472 for_each_tracing_cpu(cpu)
9473 tracing_init_tracefs_percpu(tr, cpu);
9474
9475 ftrace_init_tracefs(tr, d_tracer);
9476}
9477
9478static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
9479{
9480 struct vfsmount *mnt;
9481 struct file_system_type *type;
9482
9483 /*
9484 * To maintain backward compatibility for tools that mount
9485 * debugfs to get to the tracing facility, tracefs is automatically
9486 * mounted to the debugfs/tracing directory.
9487 */
9488 type = get_fs_type("tracefs");
9489 if (!type)
9490 return NULL;
9491 mnt = vfs_submount(mntpt, type, "tracefs", NULL);
9492 put_filesystem(type);
9493 if (IS_ERR(mnt))
9494 return NULL;
9495 mntget(mnt);
9496
9497 return mnt;
9498}
9499
9500/**
9501 * tracing_init_dentry - initialize top level trace array
9502 *
9503 * This is called when creating files or directories in the tracing
9504 * directory. It is called via fs_initcall() by any of the boot up code
9505 * and expects to return the dentry of the top level tracing directory.
9506 */
9507int tracing_init_dentry(void)
9508{
9509 struct trace_array *tr = &global_trace;
9510
9511 if (security_locked_down(LOCKDOWN_TRACEFS)) {
9512 pr_warn("Tracing disabled due to lockdown\n");
9513 return -EPERM;
9514 }
9515
9516 /* The top level trace array uses NULL as parent */
9517 if (tr->dir)
9518 return 0;
9519
9520 if (WARN_ON(!tracefs_initialized()))
9521 return -ENODEV;
9522
9523 /*
9524 * As there may still be users that expect the tracing
9525 * files to exist in debugfs/tracing, we must automount
9526 * the tracefs file system there, so older tools still
9527 * work with the newer kernel.
9528 */
9529 tr->dir = debugfs_create_automount("tracing", NULL,
9530 trace_automount, NULL);
9531
9532 return 0;
9533}
9534
9535extern struct trace_eval_map *__start_ftrace_eval_maps[];
9536extern struct trace_eval_map *__stop_ftrace_eval_maps[];
9537
9538static struct workqueue_struct *eval_map_wq __initdata;
9539static struct work_struct eval_map_work __initdata;
9540
9541static void __init eval_map_work_func(struct work_struct *work)
9542{
9543 int len;
9544
9545 len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
9546 trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
9547}
9548
9549static int __init trace_eval_init(void)
9550{
9551 INIT_WORK(&eval_map_work, eval_map_work_func);
9552
9553 eval_map_wq = alloc_workqueue("eval_map_wq", WQ_UNBOUND, 0);
9554 if (!eval_map_wq) {
9555 pr_err("Unable to allocate eval_map_wq\n");
9556 /* Do work here */
9557 eval_map_work_func(&eval_map_work);
9558 return -ENOMEM;
9559 }
9560
9561 queue_work(eval_map_wq, &eval_map_work);
9562 return 0;
9563}
9564
9565static int __init trace_eval_sync(void)
9566{
9567 /* Make sure the eval map updates are finished */
9568 if (eval_map_wq)
9569 destroy_workqueue(eval_map_wq);
9570 return 0;
9571}
9572
9573late_initcall_sync(trace_eval_sync);
9574
9575
9576#ifdef CONFIG_MODULES
9577static void trace_module_add_evals(struct module *mod)
9578{
9579 if (!mod->num_trace_evals)
9580 return;
9581
9582 /*
9583 * Modules with bad taint do not have events created, do
9584 * not bother with enums either.
9585 */
9586 if (trace_module_has_bad_taint(mod))
9587 return;
9588
9589 trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
9590}
9591
9592#ifdef CONFIG_TRACE_EVAL_MAP_FILE
9593static void trace_module_remove_evals(struct module *mod)
9594{
9595 union trace_eval_map_item *map;
9596 union trace_eval_map_item **last = &trace_eval_maps;
9597
9598 if (!mod->num_trace_evals)
9599 return;
9600
9601 mutex_lock(&trace_eval_mutex);
9602
9603 map = trace_eval_maps;
9604
9605 while (map) {
9606 if (map->head.mod == mod)
9607 break;
9608 map = trace_eval_jmp_to_tail(map);
9609 last = &map->tail.next;
9610 map = map->tail.next;
9611 }
9612 if (!map)
9613 goto out;
9614
9615 *last = trace_eval_jmp_to_tail(map)->tail.next;
9616 kfree(map);
9617 out:
9618 mutex_unlock(&trace_eval_mutex);
9619}
9620#else
9621static inline void trace_module_remove_evals(struct module *mod) { }
9622#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
9623
9624static int trace_module_notify(struct notifier_block *self,
9625 unsigned long val, void *data)
9626{
9627 struct module *mod = data;
9628
9629 switch (val) {
9630 case MODULE_STATE_COMING:
9631 trace_module_add_evals(mod);
9632 break;
9633 case MODULE_STATE_GOING:
9634 trace_module_remove_evals(mod);
9635 break;
9636 }
9637
9638 return NOTIFY_OK;
9639}
9640
9641static struct notifier_block trace_module_nb = {
9642 .notifier_call = trace_module_notify,
9643 .priority = 0,
9644};
9645#endif /* CONFIG_MODULES */
9646
9647static __init int tracer_init_tracefs(void)
9648{
9649 int ret;
9650
9651 trace_access_lock_init();
9652
9653 ret = tracing_init_dentry();
9654 if (ret)
9655 return 0;
9656
9657 event_trace_init();
9658
9659 init_tracer_tracefs(&global_trace, NULL);
9660 ftrace_init_tracefs_toplevel(&global_trace, NULL);
9661
9662 trace_create_file("tracing_thresh", 0644, NULL,
9663 &global_trace, &tracing_thresh_fops);
9664
9665 trace_create_file("README", 0444, NULL,
9666 NULL, &tracing_readme_fops);
9667
9668 trace_create_file("saved_cmdlines", 0444, NULL,
9669 NULL, &tracing_saved_cmdlines_fops);
9670
9671 trace_create_file("saved_cmdlines_size", 0644, NULL,
9672 NULL, &tracing_saved_cmdlines_size_fops);
9673
9674 trace_create_file("saved_tgids", 0444, NULL,
9675 NULL, &tracing_saved_tgids_fops);
9676
9677 trace_eval_init();
9678
9679 trace_create_eval_file(NULL);
9680
9681#ifdef CONFIG_MODULES
9682 register_module_notifier(&trace_module_nb);
9683#endif
9684
9685#ifdef CONFIG_DYNAMIC_FTRACE
9686 trace_create_file("dyn_ftrace_total_info", 0444, NULL,
9687 NULL, &tracing_dyn_info_fops);
9688#endif
9689
9690 create_trace_instances(NULL);
9691
9692 update_tracer_options(&global_trace);
9693
9694 return 0;
9695}
9696
9697fs_initcall(tracer_init_tracefs);
9698
9699static int trace_panic_handler(struct notifier_block *this,
9700 unsigned long event, void *unused)
9701{
9702 if (ftrace_dump_on_oops)
9703 ftrace_dump(ftrace_dump_on_oops);
9704 return NOTIFY_OK;
9705}
9706
9707static struct notifier_block trace_panic_notifier = {
9708 .notifier_call = trace_panic_handler,
9709 .next = NULL,
9710 .priority = 150 /* priority: INT_MAX >= x >= 0 */
9711};
9712
9713static int trace_die_handler(struct notifier_block *self,
9714 unsigned long val,
9715 void *data)
9716{
9717 switch (val) {
9718 case DIE_OOPS:
9719 if (ftrace_dump_on_oops)
9720 ftrace_dump(ftrace_dump_on_oops);
9721 break;
9722 default:
9723 break;
9724 }
9725 return NOTIFY_OK;
9726}
9727
9728static struct notifier_block trace_die_notifier = {
9729 .notifier_call = trace_die_handler,
9730 .priority = 200
9731};
9732
9733/*
9734 * printk is set to max of 1024, we really don't need it that big.
9735 * Nothing should be printing 1000 characters anyway.
9736 */
9737#define TRACE_MAX_PRINT 1000
9738
9739/*
9740 * Define here KERN_TRACE so that we have one place to modify
9741 * it if we decide to change what log level the ftrace dump
9742 * should be at.
9743 */
9744#define KERN_TRACE KERN_EMERG
9745
9746void
9747trace_printk_seq(struct trace_seq *s)
9748{
9749 /* Probably should print a warning here. */
9750 if (s->seq.len >= TRACE_MAX_PRINT)
9751 s->seq.len = TRACE_MAX_PRINT;
9752
9753 /*
9754 * More paranoid code. Although the buffer size is set to
9755 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
9756 * an extra layer of protection.
9757 */
9758 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
9759 s->seq.len = s->seq.size - 1;
9760
9761 /* should be zero ended, but we are paranoid. */
9762 s->buffer[s->seq.len] = 0;
9763
9764 printk(KERN_TRACE "%s", s->buffer);
9765
9766 trace_seq_init(s);
9767}
9768
9769void trace_init_global_iter(struct trace_iterator *iter)
9770{
9771 iter->tr = &global_trace;
9772 iter->trace = iter->tr->current_trace;
9773 iter->cpu_file = RING_BUFFER_ALL_CPUS;
9774 iter->array_buffer = &global_trace.array_buffer;
9775
9776 if (iter->trace && iter->trace->open)
9777 iter->trace->open(iter);
9778
9779 /* Annotate start of buffers if we had overruns */
9780 if (ring_buffer_overruns(iter->array_buffer->buffer))
9781 iter->iter_flags |= TRACE_FILE_ANNOTATE;
9782
9783 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
9784 if (trace_clocks[iter->tr->clock_id].in_ns)
9785 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
9786}
9787
9788void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
9789{
9790 /* use static because iter can be a bit big for the stack */
9791 static struct trace_iterator iter;
9792 static atomic_t dump_running;
9793 struct trace_array *tr = &global_trace;
9794 unsigned int old_userobj;
9795 unsigned long flags;
9796 int cnt = 0, cpu;
9797
9798 /* Only allow one dump user at a time. */
9799 if (atomic_inc_return(&dump_running) != 1) {
9800 atomic_dec(&dump_running);
9801 return;
9802 }
9803
9804 /*
9805 * Always turn off tracing when we dump.
9806 * We don't need to show trace output of what happens
9807 * between multiple crashes.
9808 *
9809 * If the user does a sysrq-z, then they can re-enable
9810 * tracing with echo 1 > tracing_on.
9811 */
9812 tracing_off();
9813
9814 local_irq_save(flags);
9815 printk_nmi_direct_enter();
9816
9817 /* Simulate the iterator */
9818 trace_init_global_iter(&iter);
9819 /* Can not use kmalloc for iter.temp and iter.fmt */
9820 iter.temp = static_temp_buf;
9821 iter.temp_size = STATIC_TEMP_BUF_SIZE;
9822 iter.fmt = static_fmt_buf;
9823 iter.fmt_size = STATIC_FMT_BUF_SIZE;
9824
9825 for_each_tracing_cpu(cpu) {
9826 atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
9827 }
9828
9829 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
9830
9831 /* don't look at user memory in panic mode */
9832 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
9833
9834 switch (oops_dump_mode) {
9835 case DUMP_ALL:
9836 iter.cpu_file = RING_BUFFER_ALL_CPUS;
9837 break;
9838 case DUMP_ORIG:
9839 iter.cpu_file = raw_smp_processor_id();
9840 break;
9841 case DUMP_NONE:
9842 goto out_enable;
9843 default:
9844 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
9845 iter.cpu_file = RING_BUFFER_ALL_CPUS;
9846 }
9847
9848 printk(KERN_TRACE "Dumping ftrace buffer:\n");
9849
9850 /* Did function tracer already get disabled? */
9851 if (ftrace_is_dead()) {
9852 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
9853 printk("# MAY BE MISSING FUNCTION EVENTS\n");
9854 }
9855
9856 /*
9857 * We need to stop all tracing on all CPUS to read
9858 * the next buffer. This is a bit expensive, but is
9859 * not done often. We fill all what we can read,
9860 * and then release the locks again.
9861 */
9862
9863 while (!trace_empty(&iter)) {
9864
9865 if (!cnt)
9866 printk(KERN_TRACE "---------------------------------\n");
9867
9868 cnt++;
9869
9870 trace_iterator_reset(&iter);
9871 iter.iter_flags |= TRACE_FILE_LAT_FMT;
9872
9873 if (trace_find_next_entry_inc(&iter) != NULL) {
9874 int ret;
9875
9876 ret = print_trace_line(&iter);
9877 if (ret != TRACE_TYPE_NO_CONSUME)
9878 trace_consume(&iter);
9879 }
9880 touch_nmi_watchdog();
9881
9882 trace_printk_seq(&iter.seq);
9883 }
9884
9885 if (!cnt)
9886 printk(KERN_TRACE " (ftrace buffer empty)\n");
9887 else
9888 printk(KERN_TRACE "---------------------------------\n");
9889
9890 out_enable:
9891 tr->trace_flags |= old_userobj;
9892
9893 for_each_tracing_cpu(cpu) {
9894 atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
9895 }
9896 atomic_dec(&dump_running);
9897 printk_nmi_direct_exit();
9898 local_irq_restore(flags);
9899}
9900EXPORT_SYMBOL_GPL(ftrace_dump);
9901
9902#define WRITE_BUFSIZE 4096
9903
9904ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
9905 size_t count, loff_t *ppos,
9906 int (*createfn)(const char *))
9907{
9908 char *kbuf, *buf, *tmp;
9909 int ret = 0;
9910 size_t done = 0;
9911 size_t size;
9912
9913 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
9914 if (!kbuf)
9915 return -ENOMEM;
9916
9917 while (done < count) {
9918 size = count - done;
9919
9920 if (size >= WRITE_BUFSIZE)
9921 size = WRITE_BUFSIZE - 1;
9922
9923 if (copy_from_user(kbuf, buffer + done, size)) {
9924 ret = -EFAULT;
9925 goto out;
9926 }
9927 kbuf[size] = '\0';
9928 buf = kbuf;
9929 do {
9930 tmp = strchr(buf, '\n');
9931 if (tmp) {
9932 *tmp = '\0';
9933 size = tmp - buf + 1;
9934 } else {
9935 size = strlen(buf);
9936 if (done + size < count) {
9937 if (buf != kbuf)
9938 break;
9939 /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
9940 pr_warn("Line length is too long: Should be less than %d\n",
9941 WRITE_BUFSIZE - 2);
9942 ret = -EINVAL;
9943 goto out;
9944 }
9945 }
9946 done += size;
9947
9948 /* Remove comments */
9949 tmp = strchr(buf, '#');
9950
9951 if (tmp)
9952 *tmp = '\0';
9953
9954 ret = createfn(buf);
9955 if (ret)
9956 goto out;
9957 buf += size;
9958
9959 } while (done < count);
9960 }
9961 ret = done;
9962
9963out:
9964 kfree(kbuf);
9965
9966 return ret;
9967}
9968
9969__init static int tracer_alloc_buffers(void)
9970{
9971 int ring_buf_size;
9972 int ret = -ENOMEM;
9973
9974
9975 if (security_locked_down(LOCKDOWN_TRACEFS)) {
9976 pr_warn("Tracing disabled due to lockdown\n");
9977 return -EPERM;
9978 }
9979
9980 /*
9981 * Make sure we don't accidentally add more trace options
9982 * than we have bits for.
9983 */
9984 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
9985
9986 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
9987 goto out;
9988
9989 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
9990 goto out_free_buffer_mask;
9991
9992 /* Only allocate trace_printk buffers if a trace_printk exists */
9993 if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
9994 /* Must be called before global_trace.buffer is allocated */
9995 trace_printk_init_buffers();
9996
9997 /* To save memory, keep the ring buffer size to its minimum */
9998 if (ring_buffer_expanded)
9999 ring_buf_size = trace_buf_size;
10000 else
10001 ring_buf_size = 1;
10002
10003 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
10004 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
10005
10006 raw_spin_lock_init(&global_trace.start_lock);
10007
10008 /*
10009 * The prepare callbacks allocates some memory for the ring buffer. We
10010 * don't free the buffer if the CPU goes down. If we were to free
10011 * the buffer, then the user would lose any trace that was in the
10012 * buffer. The memory will be removed once the "instance" is removed.
10013 */
10014 ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
10015 "trace/RB:preapre", trace_rb_cpu_prepare,
10016 NULL);
10017 if (ret < 0)
10018 goto out_free_cpumask;
10019 /* Used for event triggers */
10020 ret = -ENOMEM;
10021 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
10022 if (!temp_buffer)
10023 goto out_rm_hp_state;
10024
10025 if (trace_create_savedcmd() < 0)
10026 goto out_free_temp_buffer;
10027
10028 /* TODO: make the number of buffers hot pluggable with CPUS */
10029 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
10030 MEM_FAIL(1, "tracer: failed to allocate ring buffer!\n");
10031 goto out_free_savedcmd;
10032 }
10033
10034 if (global_trace.buffer_disabled)
10035 tracing_off();
10036
10037 if (trace_boot_clock) {
10038 ret = tracing_set_clock(&global_trace, trace_boot_clock);
10039 if (ret < 0)
10040 pr_warn("Trace clock %s not defined, going back to default\n",
10041 trace_boot_clock);
10042 }
10043
10044 /*
10045 * register_tracer() might reference current_trace, so it
10046 * needs to be set before we register anything. This is
10047 * just a bootstrap of current_trace anyway.
10048 */
10049 global_trace.current_trace = &nop_trace;
10050
10051 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
10052
10053 ftrace_init_global_array_ops(&global_trace);
10054
10055 init_trace_flags_index(&global_trace);
10056
10057 register_tracer(&nop_trace);
10058
10059 /* Function tracing may start here (via kernel command line) */
10060 init_function_trace();
10061
10062 /* All seems OK, enable tracing */
10063 tracing_disabled = 0;
10064
10065 atomic_notifier_chain_register(&panic_notifier_list,
10066 &trace_panic_notifier);
10067
10068 register_die_notifier(&trace_die_notifier);
10069
10070 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
10071
10072 INIT_LIST_HEAD(&global_trace.systems);
10073 INIT_LIST_HEAD(&global_trace.events);
10074 INIT_LIST_HEAD(&global_trace.hist_vars);
10075 INIT_LIST_HEAD(&global_trace.err_log);
10076 list_add(&global_trace.list, &ftrace_trace_arrays);
10077
10078 apply_trace_boot_options();
10079
10080 register_snapshot_cmd();
10081
10082 test_can_verify();
10083
10084 return 0;
10085
10086out_free_savedcmd:
10087 free_saved_cmdlines_buffer(savedcmd);
10088out_free_temp_buffer:
10089 ring_buffer_free(temp_buffer);
10090out_rm_hp_state:
10091 cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
10092out_free_cpumask:
10093 free_cpumask_var(global_trace.tracing_cpumask);
10094out_free_buffer_mask:
10095 free_cpumask_var(tracing_buffer_mask);
10096out:
10097 return ret;
10098}
10099
10100void __init early_trace_init(void)
10101{
10102 if (tracepoint_printk) {
10103 tracepoint_print_iter =
10104 kzalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
10105 if (MEM_FAIL(!tracepoint_print_iter,
10106 "Failed to allocate trace iterator\n"))
10107 tracepoint_printk = 0;
10108 else
10109 static_key_enable(&tracepoint_printk_key.key);
10110 }
10111 tracer_alloc_buffers();
10112}
10113
10114void __init trace_init(void)
10115{
10116 trace_event_init();
10117}
10118
10119__init static void clear_boot_tracer(void)
10120{
10121 /*
10122 * The default tracer at boot buffer is an init section.
10123 * This function is called in lateinit. If we did not
10124 * find the boot tracer, then clear it out, to prevent
10125 * later registration from accessing the buffer that is
10126 * about to be freed.
10127 */
10128 if (!default_bootup_tracer)
10129 return;
10130
10131 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
10132 default_bootup_tracer);
10133 default_bootup_tracer = NULL;
10134}
10135
10136#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
10137__init static void tracing_set_default_clock(void)
10138{
10139 /* sched_clock_stable() is determined in late_initcall */
10140 if (!trace_boot_clock && !sched_clock_stable()) {
10141 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10142 pr_warn("Can not set tracing clock due to lockdown\n");
10143 return;
10144 }
10145
10146 printk(KERN_WARNING
10147 "Unstable clock detected, switching default tracing clock to \"global\"\n"
10148 "If you want to keep using the local clock, then add:\n"
10149 " \"trace_clock=local\"\n"
10150 "on the kernel command line\n");
10151 tracing_set_clock(&global_trace, "global");
10152 }
10153}
10154#else
10155static inline void tracing_set_default_clock(void) { }
10156#endif
10157
10158__init static int late_trace_init(void)
10159{
10160 if (tracepoint_printk && tracepoint_printk_stop_on_boot) {
10161 static_key_disable(&tracepoint_printk_key.key);
10162 tracepoint_printk = 0;
10163 }
10164
10165 tracing_set_default_clock();
10166 clear_boot_tracer();
10167 return 0;
10168}
10169
10170late_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/tracefs.h>
24#include <linux/pagemap.h>
25#include <linux/hardirq.h>
26#include <linux/linkage.h>
27#include <linux/uaccess.h>
28#include <linux/vmalloc.h>
29#include <linux/ftrace.h>
30#include <linux/module.h>
31#include <linux/percpu.h>
32#include <linux/splice.h>
33#include <linux/kdebug.h>
34#include <linux/string.h>
35#include <linux/mount.h>
36#include <linux/rwsem.h>
37#include <linux/slab.h>
38#include <linux/ctype.h>
39#include <linux/init.h>
40#include <linux/poll.h>
41#include <linux/nmi.h>
42#include <linux/fs.h>
43#include <linux/trace.h>
44#include <linux/sched/rt.h>
45
46#include "trace.h"
47#include "trace_output.h"
48
49/*
50 * On boot up, the ring buffer is set to the minimum size, so that
51 * we do not waste memory on systems that are not using tracing.
52 */
53bool ring_buffer_expanded;
54
55/*
56 * We need to change this state when a selftest is running.
57 * A selftest will lurk into the ring-buffer to count the
58 * entries inserted during the selftest although some concurrent
59 * insertions into the ring-buffer such as trace_printk could occurred
60 * at the same time, giving false positive or negative results.
61 */
62static bool __read_mostly tracing_selftest_running;
63
64/*
65 * If a tracer is running, we do not want to run SELFTEST.
66 */
67bool __read_mostly tracing_selftest_disabled;
68
69/* Pipe tracepoints to printk */
70struct trace_iterator *tracepoint_print_iter;
71int tracepoint_printk;
72static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
73
74/* For tracers that don't implement custom flags */
75static struct tracer_opt dummy_tracer_opt[] = {
76 { }
77};
78
79static int
80dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
81{
82 return 0;
83}
84
85/*
86 * To prevent the comm cache from being overwritten when no
87 * tracing is active, only save the comm when a trace event
88 * occurred.
89 */
90static DEFINE_PER_CPU(bool, trace_cmdline_save);
91
92/*
93 * Kill all tracing for good (never come back).
94 * It is initialized to 1 but will turn to zero if the initialization
95 * of the tracer is successful. But that is the only place that sets
96 * this back to zero.
97 */
98static int tracing_disabled = 1;
99
100cpumask_var_t __read_mostly tracing_buffer_mask;
101
102/*
103 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
104 *
105 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
106 * is set, then ftrace_dump is called. This will output the contents
107 * of the ftrace buffers to the console. This is very useful for
108 * capturing traces that lead to crashes and outputing it to a
109 * serial console.
110 *
111 * It is default off, but you can enable it with either specifying
112 * "ftrace_dump_on_oops" in the kernel command line, or setting
113 * /proc/sys/kernel/ftrace_dump_on_oops
114 * Set 1 if you want to dump buffers of all CPUs
115 * Set 2 if you want to dump the buffer of the CPU that triggered oops
116 */
117
118enum ftrace_dump_mode ftrace_dump_on_oops;
119
120/* When set, tracing will stop when a WARN*() is hit */
121int __disable_trace_on_warning;
122
123#ifdef CONFIG_TRACE_ENUM_MAP_FILE
124/* Map of enums to their values, for "enum_map" file */
125struct trace_enum_map_head {
126 struct module *mod;
127 unsigned long length;
128};
129
130union trace_enum_map_item;
131
132struct trace_enum_map_tail {
133 /*
134 * "end" is first and points to NULL as it must be different
135 * than "mod" or "enum_string"
136 */
137 union trace_enum_map_item *next;
138 const char *end; /* points to NULL */
139};
140
141static DEFINE_MUTEX(trace_enum_mutex);
142
143/*
144 * The trace_enum_maps are saved in an array with two extra elements,
145 * one at the beginning, and one at the end. The beginning item contains
146 * the count of the saved maps (head.length), and the module they
147 * belong to if not built in (head.mod). The ending item contains a
148 * pointer to the next array of saved enum_map items.
149 */
150union trace_enum_map_item {
151 struct trace_enum_map map;
152 struct trace_enum_map_head head;
153 struct trace_enum_map_tail tail;
154};
155
156static union trace_enum_map_item *trace_enum_maps;
157#endif /* CONFIG_TRACE_ENUM_MAP_FILE */
158
159static int tracing_set_tracer(struct trace_array *tr, const char *buf);
160
161#define MAX_TRACER_SIZE 100
162static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
163static char *default_bootup_tracer;
164
165static bool allocate_snapshot;
166
167static int __init set_cmdline_ftrace(char *str)
168{
169 strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
170 default_bootup_tracer = bootup_tracer_buf;
171 /* We are using ftrace early, expand it */
172 ring_buffer_expanded = true;
173 return 1;
174}
175__setup("ftrace=", set_cmdline_ftrace);
176
177static int __init set_ftrace_dump_on_oops(char *str)
178{
179 if (*str++ != '=' || !*str) {
180 ftrace_dump_on_oops = DUMP_ALL;
181 return 1;
182 }
183
184 if (!strcmp("orig_cpu", str)) {
185 ftrace_dump_on_oops = DUMP_ORIG;
186 return 1;
187 }
188
189 return 0;
190}
191__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
192
193static int __init stop_trace_on_warning(char *str)
194{
195 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
196 __disable_trace_on_warning = 1;
197 return 1;
198}
199__setup("traceoff_on_warning", stop_trace_on_warning);
200
201static int __init boot_alloc_snapshot(char *str)
202{
203 allocate_snapshot = true;
204 /* We also need the main ring buffer expanded */
205 ring_buffer_expanded = true;
206 return 1;
207}
208__setup("alloc_snapshot", boot_alloc_snapshot);
209
210
211static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
212
213static int __init set_trace_boot_options(char *str)
214{
215 strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
216 return 0;
217}
218__setup("trace_options=", set_trace_boot_options);
219
220static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
221static char *trace_boot_clock __initdata;
222
223static int __init set_trace_boot_clock(char *str)
224{
225 strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
226 trace_boot_clock = trace_boot_clock_buf;
227 return 0;
228}
229__setup("trace_clock=", set_trace_boot_clock);
230
231static int __init set_tracepoint_printk(char *str)
232{
233 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
234 tracepoint_printk = 1;
235 return 1;
236}
237__setup("tp_printk", set_tracepoint_printk);
238
239unsigned long long ns2usecs(u64 nsec)
240{
241 nsec += 500;
242 do_div(nsec, 1000);
243 return nsec;
244}
245
246/* trace_flags holds trace_options default values */
247#define TRACE_DEFAULT_FLAGS \
248 (FUNCTION_DEFAULT_FLAGS | \
249 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
250 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
251 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
252 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS)
253
254/* trace_options that are only supported by global_trace */
255#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
256 TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
257
258/* trace_flags that are default zero for instances */
259#define ZEROED_TRACE_FLAGS \
260 TRACE_ITER_EVENT_FORK
261
262/*
263 * The global_trace is the descriptor that holds the tracing
264 * buffers for the live tracing. For each CPU, it contains
265 * a link list of pages that will store trace entries. The
266 * page descriptor of the pages in the memory is used to hold
267 * the link list by linking the lru item in the page descriptor
268 * to each of the pages in the buffer per CPU.
269 *
270 * For each active CPU there is a data field that holds the
271 * pages for the buffer for that CPU. Each CPU has the same number
272 * of pages allocated for its buffer.
273 */
274static struct trace_array global_trace = {
275 .trace_flags = TRACE_DEFAULT_FLAGS,
276};
277
278LIST_HEAD(ftrace_trace_arrays);
279
280int trace_array_get(struct trace_array *this_tr)
281{
282 struct trace_array *tr;
283 int ret = -ENODEV;
284
285 mutex_lock(&trace_types_lock);
286 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
287 if (tr == this_tr) {
288 tr->ref++;
289 ret = 0;
290 break;
291 }
292 }
293 mutex_unlock(&trace_types_lock);
294
295 return ret;
296}
297
298static void __trace_array_put(struct trace_array *this_tr)
299{
300 WARN_ON(!this_tr->ref);
301 this_tr->ref--;
302}
303
304void trace_array_put(struct trace_array *this_tr)
305{
306 mutex_lock(&trace_types_lock);
307 __trace_array_put(this_tr);
308 mutex_unlock(&trace_types_lock);
309}
310
311int call_filter_check_discard(struct trace_event_call *call, void *rec,
312 struct ring_buffer *buffer,
313 struct ring_buffer_event *event)
314{
315 if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
316 !filter_match_preds(call->filter, rec)) {
317 __trace_event_discard_commit(buffer, event);
318 return 1;
319 }
320
321 return 0;
322}
323
324void trace_free_pid_list(struct trace_pid_list *pid_list)
325{
326 vfree(pid_list->pids);
327 kfree(pid_list);
328}
329
330/**
331 * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
332 * @filtered_pids: The list of pids to check
333 * @search_pid: The PID to find in @filtered_pids
334 *
335 * Returns true if @search_pid is fonud in @filtered_pids, and false otherwis.
336 */
337bool
338trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
339{
340 /*
341 * If pid_max changed after filtered_pids was created, we
342 * by default ignore all pids greater than the previous pid_max.
343 */
344 if (search_pid >= filtered_pids->pid_max)
345 return false;
346
347 return test_bit(search_pid, filtered_pids->pids);
348}
349
350/**
351 * trace_ignore_this_task - should a task be ignored for tracing
352 * @filtered_pids: The list of pids to check
353 * @task: The task that should be ignored if not filtered
354 *
355 * Checks if @task should be traced or not from @filtered_pids.
356 * Returns true if @task should *NOT* be traced.
357 * Returns false if @task should be traced.
358 */
359bool
360trace_ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct *task)
361{
362 /*
363 * Return false, because if filtered_pids does not exist,
364 * all pids are good to trace.
365 */
366 if (!filtered_pids)
367 return false;
368
369 return !trace_find_filtered_pid(filtered_pids, task->pid);
370}
371
372/**
373 * trace_pid_filter_add_remove - Add or remove a task from a pid_list
374 * @pid_list: The list to modify
375 * @self: The current task for fork or NULL for exit
376 * @task: The task to add or remove
377 *
378 * If adding a task, if @self is defined, the task is only added if @self
379 * is also included in @pid_list. This happens on fork and tasks should
380 * only be added when the parent is listed. If @self is NULL, then the
381 * @task pid will be removed from the list, which would happen on exit
382 * of a task.
383 */
384void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
385 struct task_struct *self,
386 struct task_struct *task)
387{
388 if (!pid_list)
389 return;
390
391 /* For forks, we only add if the forking task is listed */
392 if (self) {
393 if (!trace_find_filtered_pid(pid_list, self->pid))
394 return;
395 }
396
397 /* Sorry, but we don't support pid_max changing after setting */
398 if (task->pid >= pid_list->pid_max)
399 return;
400
401 /* "self" is set for forks, and NULL for exits */
402 if (self)
403 set_bit(task->pid, pid_list->pids);
404 else
405 clear_bit(task->pid, pid_list->pids);
406}
407
408/**
409 * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
410 * @pid_list: The pid list to show
411 * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
412 * @pos: The position of the file
413 *
414 * This is used by the seq_file "next" operation to iterate the pids
415 * listed in a trace_pid_list structure.
416 *
417 * Returns the pid+1 as we want to display pid of zero, but NULL would
418 * stop the iteration.
419 */
420void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
421{
422 unsigned long pid = (unsigned long)v;
423
424 (*pos)++;
425
426 /* pid already is +1 of the actual prevous bit */
427 pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
428
429 /* Return pid + 1 to allow zero to be represented */
430 if (pid < pid_list->pid_max)
431 return (void *)(pid + 1);
432
433 return NULL;
434}
435
436/**
437 * trace_pid_start - Used for seq_file to start reading pid lists
438 * @pid_list: The pid list to show
439 * @pos: The position of the file
440 *
441 * This is used by seq_file "start" operation to start the iteration
442 * of listing pids.
443 *
444 * Returns the pid+1 as we want to display pid of zero, but NULL would
445 * stop the iteration.
446 */
447void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
448{
449 unsigned long pid;
450 loff_t l = 0;
451
452 pid = find_first_bit(pid_list->pids, pid_list->pid_max);
453 if (pid >= pid_list->pid_max)
454 return NULL;
455
456 /* Return pid + 1 so that zero can be the exit value */
457 for (pid++; pid && l < *pos;
458 pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
459 ;
460 return (void *)pid;
461}
462
463/**
464 * trace_pid_show - show the current pid in seq_file processing
465 * @m: The seq_file structure to write into
466 * @v: A void pointer of the pid (+1) value to display
467 *
468 * Can be directly used by seq_file operations to display the current
469 * pid value.
470 */
471int trace_pid_show(struct seq_file *m, void *v)
472{
473 unsigned long pid = (unsigned long)v - 1;
474
475 seq_printf(m, "%lu\n", pid);
476 return 0;
477}
478
479/* 128 should be much more than enough */
480#define PID_BUF_SIZE 127
481
482int trace_pid_write(struct trace_pid_list *filtered_pids,
483 struct trace_pid_list **new_pid_list,
484 const char __user *ubuf, size_t cnt)
485{
486 struct trace_pid_list *pid_list;
487 struct trace_parser parser;
488 unsigned long val;
489 int nr_pids = 0;
490 ssize_t read = 0;
491 ssize_t ret = 0;
492 loff_t pos;
493 pid_t pid;
494
495 if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
496 return -ENOMEM;
497
498 /*
499 * Always recreate a new array. The write is an all or nothing
500 * operation. Always create a new array when adding new pids by
501 * the user. If the operation fails, then the current list is
502 * not modified.
503 */
504 pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
505 if (!pid_list)
506 return -ENOMEM;
507
508 pid_list->pid_max = READ_ONCE(pid_max);
509
510 /* Only truncating will shrink pid_max */
511 if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max)
512 pid_list->pid_max = filtered_pids->pid_max;
513
514 pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
515 if (!pid_list->pids) {
516 kfree(pid_list);
517 return -ENOMEM;
518 }
519
520 if (filtered_pids) {
521 /* copy the current bits to the new max */
522 for_each_set_bit(pid, filtered_pids->pids,
523 filtered_pids->pid_max) {
524 set_bit(pid, pid_list->pids);
525 nr_pids++;
526 }
527 }
528
529 while (cnt > 0) {
530
531 pos = 0;
532
533 ret = trace_get_user(&parser, ubuf, cnt, &pos);
534 if (ret < 0 || !trace_parser_loaded(&parser))
535 break;
536
537 read += ret;
538 ubuf += ret;
539 cnt -= ret;
540
541 parser.buffer[parser.idx] = 0;
542
543 ret = -EINVAL;
544 if (kstrtoul(parser.buffer, 0, &val))
545 break;
546 if (val >= pid_list->pid_max)
547 break;
548
549 pid = (pid_t)val;
550
551 set_bit(pid, pid_list->pids);
552 nr_pids++;
553
554 trace_parser_clear(&parser);
555 ret = 0;
556 }
557 trace_parser_put(&parser);
558
559 if (ret < 0) {
560 trace_free_pid_list(pid_list);
561 return ret;
562 }
563
564 if (!nr_pids) {
565 /* Cleared the list of pids */
566 trace_free_pid_list(pid_list);
567 read = ret;
568 pid_list = NULL;
569 }
570
571 *new_pid_list = pid_list;
572
573 return read;
574}
575
576static u64 buffer_ftrace_now(struct trace_buffer *buf, int cpu)
577{
578 u64 ts;
579
580 /* Early boot up does not have a buffer yet */
581 if (!buf->buffer)
582 return trace_clock_local();
583
584 ts = ring_buffer_time_stamp(buf->buffer, cpu);
585 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
586
587 return ts;
588}
589
590u64 ftrace_now(int cpu)
591{
592 return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
593}
594
595/**
596 * tracing_is_enabled - Show if global_trace has been disabled
597 *
598 * Shows if the global trace has been enabled or not. It uses the
599 * mirror flag "buffer_disabled" to be used in fast paths such as for
600 * the irqsoff tracer. But it may be inaccurate due to races. If you
601 * need to know the accurate state, use tracing_is_on() which is a little
602 * slower, but accurate.
603 */
604int tracing_is_enabled(void)
605{
606 /*
607 * For quick access (irqsoff uses this in fast path), just
608 * return the mirror variable of the state of the ring buffer.
609 * It's a little racy, but we don't really care.
610 */
611 smp_rmb();
612 return !global_trace.buffer_disabled;
613}
614
615/*
616 * trace_buf_size is the size in bytes that is allocated
617 * for a buffer. Note, the number of bytes is always rounded
618 * to page size.
619 *
620 * This number is purposely set to a low number of 16384.
621 * If the dump on oops happens, it will be much appreciated
622 * to not have to wait for all that output. Anyway this can be
623 * boot time and run time configurable.
624 */
625#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
626
627static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
628
629/* trace_types holds a link list of available tracers. */
630static struct tracer *trace_types __read_mostly;
631
632/*
633 * trace_types_lock is used to protect the trace_types list.
634 */
635DEFINE_MUTEX(trace_types_lock);
636
637/*
638 * serialize the access of the ring buffer
639 *
640 * ring buffer serializes readers, but it is low level protection.
641 * The validity of the events (which returns by ring_buffer_peek() ..etc)
642 * are not protected by ring buffer.
643 *
644 * The content of events may become garbage if we allow other process consumes
645 * these events concurrently:
646 * A) the page of the consumed events may become a normal page
647 * (not reader page) in ring buffer, and this page will be rewrited
648 * by events producer.
649 * B) The page of the consumed events may become a page for splice_read,
650 * and this page will be returned to system.
651 *
652 * These primitives allow multi process access to different cpu ring buffer
653 * concurrently.
654 *
655 * These primitives don't distinguish read-only and read-consume access.
656 * Multi read-only access are also serialized.
657 */
658
659#ifdef CONFIG_SMP
660static DECLARE_RWSEM(all_cpu_access_lock);
661static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
662
663static inline void trace_access_lock(int cpu)
664{
665 if (cpu == RING_BUFFER_ALL_CPUS) {
666 /* gain it for accessing the whole ring buffer. */
667 down_write(&all_cpu_access_lock);
668 } else {
669 /* gain it for accessing a cpu ring buffer. */
670
671 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
672 down_read(&all_cpu_access_lock);
673
674 /* Secondly block other access to this @cpu ring buffer. */
675 mutex_lock(&per_cpu(cpu_access_lock, cpu));
676 }
677}
678
679static inline void trace_access_unlock(int cpu)
680{
681 if (cpu == RING_BUFFER_ALL_CPUS) {
682 up_write(&all_cpu_access_lock);
683 } else {
684 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
685 up_read(&all_cpu_access_lock);
686 }
687}
688
689static inline void trace_access_lock_init(void)
690{
691 int cpu;
692
693 for_each_possible_cpu(cpu)
694 mutex_init(&per_cpu(cpu_access_lock, cpu));
695}
696
697#else
698
699static DEFINE_MUTEX(access_lock);
700
701static inline void trace_access_lock(int cpu)
702{
703 (void)cpu;
704 mutex_lock(&access_lock);
705}
706
707static inline void trace_access_unlock(int cpu)
708{
709 (void)cpu;
710 mutex_unlock(&access_lock);
711}
712
713static inline void trace_access_lock_init(void)
714{
715}
716
717#endif
718
719#ifdef CONFIG_STACKTRACE
720static void __ftrace_trace_stack(struct ring_buffer *buffer,
721 unsigned long flags,
722 int skip, int pc, struct pt_regs *regs);
723static inline void ftrace_trace_stack(struct trace_array *tr,
724 struct ring_buffer *buffer,
725 unsigned long flags,
726 int skip, int pc, struct pt_regs *regs);
727
728#else
729static inline void __ftrace_trace_stack(struct ring_buffer *buffer,
730 unsigned long flags,
731 int skip, int pc, struct pt_regs *regs)
732{
733}
734static inline void ftrace_trace_stack(struct trace_array *tr,
735 struct ring_buffer *buffer,
736 unsigned long flags,
737 int skip, int pc, struct pt_regs *regs)
738{
739}
740
741#endif
742
743static __always_inline void
744trace_event_setup(struct ring_buffer_event *event,
745 int type, unsigned long flags, int pc)
746{
747 struct trace_entry *ent = ring_buffer_event_data(event);
748
749 tracing_generic_entry_update(ent, flags, pc);
750 ent->type = type;
751}
752
753static __always_inline struct ring_buffer_event *
754__trace_buffer_lock_reserve(struct ring_buffer *buffer,
755 int type,
756 unsigned long len,
757 unsigned long flags, int pc)
758{
759 struct ring_buffer_event *event;
760
761 event = ring_buffer_lock_reserve(buffer, len);
762 if (event != NULL)
763 trace_event_setup(event, type, flags, pc);
764
765 return event;
766}
767
768static void tracer_tracing_on(struct trace_array *tr)
769{
770 if (tr->trace_buffer.buffer)
771 ring_buffer_record_on(tr->trace_buffer.buffer);
772 /*
773 * This flag is looked at when buffers haven't been allocated
774 * yet, or by some tracers (like irqsoff), that just want to
775 * know if the ring buffer has been disabled, but it can handle
776 * races of where it gets disabled but we still do a record.
777 * As the check is in the fast path of the tracers, it is more
778 * important to be fast than accurate.
779 */
780 tr->buffer_disabled = 0;
781 /* Make the flag seen by readers */
782 smp_wmb();
783}
784
785/**
786 * tracing_on - enable tracing buffers
787 *
788 * This function enables tracing buffers that may have been
789 * disabled with tracing_off.
790 */
791void tracing_on(void)
792{
793 tracer_tracing_on(&global_trace);
794}
795EXPORT_SYMBOL_GPL(tracing_on);
796
797
798static __always_inline void
799__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
800{
801 __this_cpu_write(trace_cmdline_save, true);
802
803 /* If this is the temp buffer, we need to commit fully */
804 if (this_cpu_read(trace_buffered_event) == event) {
805 /* Length is in event->array[0] */
806 ring_buffer_write(buffer, event->array[0], &event->array[1]);
807 /* Release the temp buffer */
808 this_cpu_dec(trace_buffered_event_cnt);
809 } else
810 ring_buffer_unlock_commit(buffer, event);
811}
812
813/**
814 * __trace_puts - write a constant string into the trace buffer.
815 * @ip: The address of the caller
816 * @str: The constant string to write
817 * @size: The size of the string.
818 */
819int __trace_puts(unsigned long ip, const char *str, int size)
820{
821 struct ring_buffer_event *event;
822 struct ring_buffer *buffer;
823 struct print_entry *entry;
824 unsigned long irq_flags;
825 int alloc;
826 int pc;
827
828 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
829 return 0;
830
831 pc = preempt_count();
832
833 if (unlikely(tracing_selftest_running || tracing_disabled))
834 return 0;
835
836 alloc = sizeof(*entry) + size + 2; /* possible \n added */
837
838 local_save_flags(irq_flags);
839 buffer = global_trace.trace_buffer.buffer;
840 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
841 irq_flags, pc);
842 if (!event)
843 return 0;
844
845 entry = ring_buffer_event_data(event);
846 entry->ip = ip;
847
848 memcpy(&entry->buf, str, size);
849
850 /* Add a newline if necessary */
851 if (entry->buf[size - 1] != '\n') {
852 entry->buf[size] = '\n';
853 entry->buf[size + 1] = '\0';
854 } else
855 entry->buf[size] = '\0';
856
857 __buffer_unlock_commit(buffer, event);
858 ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
859
860 return size;
861}
862EXPORT_SYMBOL_GPL(__trace_puts);
863
864/**
865 * __trace_bputs - write the pointer to a constant string into trace buffer
866 * @ip: The address of the caller
867 * @str: The constant string to write to the buffer to
868 */
869int __trace_bputs(unsigned long ip, const char *str)
870{
871 struct ring_buffer_event *event;
872 struct ring_buffer *buffer;
873 struct bputs_entry *entry;
874 unsigned long irq_flags;
875 int size = sizeof(struct bputs_entry);
876 int pc;
877
878 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
879 return 0;
880
881 pc = preempt_count();
882
883 if (unlikely(tracing_selftest_running || tracing_disabled))
884 return 0;
885
886 local_save_flags(irq_flags);
887 buffer = global_trace.trace_buffer.buffer;
888 event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
889 irq_flags, pc);
890 if (!event)
891 return 0;
892
893 entry = ring_buffer_event_data(event);
894 entry->ip = ip;
895 entry->str = str;
896
897 __buffer_unlock_commit(buffer, event);
898 ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
899
900 return 1;
901}
902EXPORT_SYMBOL_GPL(__trace_bputs);
903
904#ifdef CONFIG_TRACER_SNAPSHOT
905/**
906 * trace_snapshot - take a snapshot of the current buffer.
907 *
908 * This causes a swap between the snapshot buffer and the current live
909 * tracing buffer. You can use this to take snapshots of the live
910 * trace when some condition is triggered, but continue to trace.
911 *
912 * Note, make sure to allocate the snapshot with either
913 * a tracing_snapshot_alloc(), or by doing it manually
914 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
915 *
916 * If the snapshot buffer is not allocated, it will stop tracing.
917 * Basically making a permanent snapshot.
918 */
919void tracing_snapshot(void)
920{
921 struct trace_array *tr = &global_trace;
922 struct tracer *tracer = tr->current_trace;
923 unsigned long flags;
924
925 if (in_nmi()) {
926 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
927 internal_trace_puts("*** snapshot is being ignored ***\n");
928 return;
929 }
930
931 if (!tr->allocated_snapshot) {
932 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
933 internal_trace_puts("*** stopping trace here! ***\n");
934 tracing_off();
935 return;
936 }
937
938 /* Note, snapshot can not be used when the tracer uses it */
939 if (tracer->use_max_tr) {
940 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
941 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
942 return;
943 }
944
945 local_irq_save(flags);
946 update_max_tr(tr, current, smp_processor_id());
947 local_irq_restore(flags);
948}
949EXPORT_SYMBOL_GPL(tracing_snapshot);
950
951static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
952 struct trace_buffer *size_buf, int cpu_id);
953static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
954
955static int alloc_snapshot(struct trace_array *tr)
956{
957 int ret;
958
959 if (!tr->allocated_snapshot) {
960
961 /* allocate spare buffer */
962 ret = resize_buffer_duplicate_size(&tr->max_buffer,
963 &tr->trace_buffer, RING_BUFFER_ALL_CPUS);
964 if (ret < 0)
965 return ret;
966
967 tr->allocated_snapshot = true;
968 }
969
970 return 0;
971}
972
973static void free_snapshot(struct trace_array *tr)
974{
975 /*
976 * We don't free the ring buffer. instead, resize it because
977 * The max_tr ring buffer has some state (e.g. ring->clock) and
978 * we want preserve it.
979 */
980 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
981 set_buffer_entries(&tr->max_buffer, 1);
982 tracing_reset_online_cpus(&tr->max_buffer);
983 tr->allocated_snapshot = false;
984}
985
986/**
987 * tracing_alloc_snapshot - allocate snapshot buffer.
988 *
989 * This only allocates the snapshot buffer if it isn't already
990 * allocated - it doesn't also take a snapshot.
991 *
992 * This is meant to be used in cases where the snapshot buffer needs
993 * to be set up for events that can't sleep but need to be able to
994 * trigger a snapshot.
995 */
996int tracing_alloc_snapshot(void)
997{
998 struct trace_array *tr = &global_trace;
999 int ret;
1000
1001 ret = alloc_snapshot(tr);
1002 WARN_ON(ret < 0);
1003
1004 return ret;
1005}
1006EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1007
1008/**
1009 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
1010 *
1011 * This is similar to trace_snapshot(), but it will allocate the
1012 * snapshot buffer if it isn't already allocated. Use this only
1013 * where it is safe to sleep, as the allocation may sleep.
1014 *
1015 * This causes a swap between the snapshot buffer and the current live
1016 * tracing buffer. You can use this to take snapshots of the live
1017 * trace when some condition is triggered, but continue to trace.
1018 */
1019void tracing_snapshot_alloc(void)
1020{
1021 int ret;
1022
1023 ret = tracing_alloc_snapshot();
1024 if (ret < 0)
1025 return;
1026
1027 tracing_snapshot();
1028}
1029EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1030#else
1031void tracing_snapshot(void)
1032{
1033 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
1034}
1035EXPORT_SYMBOL_GPL(tracing_snapshot);
1036int tracing_alloc_snapshot(void)
1037{
1038 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
1039 return -ENODEV;
1040}
1041EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1042void tracing_snapshot_alloc(void)
1043{
1044 /* Give warning */
1045 tracing_snapshot();
1046}
1047EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1048#endif /* CONFIG_TRACER_SNAPSHOT */
1049
1050static void tracer_tracing_off(struct trace_array *tr)
1051{
1052 if (tr->trace_buffer.buffer)
1053 ring_buffer_record_off(tr->trace_buffer.buffer);
1054 /*
1055 * This flag is looked at when buffers haven't been allocated
1056 * yet, or by some tracers (like irqsoff), that just want to
1057 * know if the ring buffer has been disabled, but it can handle
1058 * races of where it gets disabled but we still do a record.
1059 * As the check is in the fast path of the tracers, it is more
1060 * important to be fast than accurate.
1061 */
1062 tr->buffer_disabled = 1;
1063 /* Make the flag seen by readers */
1064 smp_wmb();
1065}
1066
1067/**
1068 * tracing_off - turn off tracing buffers
1069 *
1070 * This function stops the tracing buffers from recording data.
1071 * It does not disable any overhead the tracers themselves may
1072 * be causing. This function simply causes all recording to
1073 * the ring buffers to fail.
1074 */
1075void tracing_off(void)
1076{
1077 tracer_tracing_off(&global_trace);
1078}
1079EXPORT_SYMBOL_GPL(tracing_off);
1080
1081void disable_trace_on_warning(void)
1082{
1083 if (__disable_trace_on_warning)
1084 tracing_off();
1085}
1086
1087/**
1088 * tracer_tracing_is_on - show real state of ring buffer enabled
1089 * @tr : the trace array to know if ring buffer is enabled
1090 *
1091 * Shows real state of the ring buffer if it is enabled or not.
1092 */
1093int tracer_tracing_is_on(struct trace_array *tr)
1094{
1095 if (tr->trace_buffer.buffer)
1096 return ring_buffer_record_is_on(tr->trace_buffer.buffer);
1097 return !tr->buffer_disabled;
1098}
1099
1100/**
1101 * tracing_is_on - show state of ring buffers enabled
1102 */
1103int tracing_is_on(void)
1104{
1105 return tracer_tracing_is_on(&global_trace);
1106}
1107EXPORT_SYMBOL_GPL(tracing_is_on);
1108
1109static int __init set_buf_size(char *str)
1110{
1111 unsigned long buf_size;
1112
1113 if (!str)
1114 return 0;
1115 buf_size = memparse(str, &str);
1116 /* nr_entries can not be zero */
1117 if (buf_size == 0)
1118 return 0;
1119 trace_buf_size = buf_size;
1120 return 1;
1121}
1122__setup("trace_buf_size=", set_buf_size);
1123
1124static int __init set_tracing_thresh(char *str)
1125{
1126 unsigned long threshold;
1127 int ret;
1128
1129 if (!str)
1130 return 0;
1131 ret = kstrtoul(str, 0, &threshold);
1132 if (ret < 0)
1133 return 0;
1134 tracing_thresh = threshold * 1000;
1135 return 1;
1136}
1137__setup("tracing_thresh=", set_tracing_thresh);
1138
1139unsigned long nsecs_to_usecs(unsigned long nsecs)
1140{
1141 return nsecs / 1000;
1142}
1143
1144/*
1145 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
1146 * It uses C(a, b) where 'a' is the enum name and 'b' is the string that
1147 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
1148 * of strings in the order that the enums were defined.
1149 */
1150#undef C
1151#define C(a, b) b
1152
1153/* These must match the bit postions in trace_iterator_flags */
1154static const char *trace_options[] = {
1155 TRACE_FLAGS
1156 NULL
1157};
1158
1159static struct {
1160 u64 (*func)(void);
1161 const char *name;
1162 int in_ns; /* is this clock in nanoseconds? */
1163} trace_clocks[] = {
1164 { trace_clock_local, "local", 1 },
1165 { trace_clock_global, "global", 1 },
1166 { trace_clock_counter, "counter", 0 },
1167 { trace_clock_jiffies, "uptime", 0 },
1168 { trace_clock, "perf", 1 },
1169 { ktime_get_mono_fast_ns, "mono", 1 },
1170 { ktime_get_raw_fast_ns, "mono_raw", 1 },
1171 { ktime_get_boot_fast_ns, "boot", 1 },
1172 ARCH_TRACE_CLOCKS
1173};
1174
1175/*
1176 * trace_parser_get_init - gets the buffer for trace parser
1177 */
1178int trace_parser_get_init(struct trace_parser *parser, int size)
1179{
1180 memset(parser, 0, sizeof(*parser));
1181
1182 parser->buffer = kmalloc(size, GFP_KERNEL);
1183 if (!parser->buffer)
1184 return 1;
1185
1186 parser->size = size;
1187 return 0;
1188}
1189
1190/*
1191 * trace_parser_put - frees the buffer for trace parser
1192 */
1193void trace_parser_put(struct trace_parser *parser)
1194{
1195 kfree(parser->buffer);
1196}
1197
1198/*
1199 * trace_get_user - reads the user input string separated by space
1200 * (matched by isspace(ch))
1201 *
1202 * For each string found the 'struct trace_parser' is updated,
1203 * and the function returns.
1204 *
1205 * Returns number of bytes read.
1206 *
1207 * See kernel/trace/trace.h for 'struct trace_parser' details.
1208 */
1209int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1210 size_t cnt, loff_t *ppos)
1211{
1212 char ch;
1213 size_t read = 0;
1214 ssize_t ret;
1215
1216 if (!*ppos)
1217 trace_parser_clear(parser);
1218
1219 ret = get_user(ch, ubuf++);
1220 if (ret)
1221 goto out;
1222
1223 read++;
1224 cnt--;
1225
1226 /*
1227 * The parser is not finished with the last write,
1228 * continue reading the user input without skipping spaces.
1229 */
1230 if (!parser->cont) {
1231 /* skip white space */
1232 while (cnt && isspace(ch)) {
1233 ret = get_user(ch, ubuf++);
1234 if (ret)
1235 goto out;
1236 read++;
1237 cnt--;
1238 }
1239
1240 /* only spaces were written */
1241 if (isspace(ch)) {
1242 *ppos += read;
1243 ret = read;
1244 goto out;
1245 }
1246
1247 parser->idx = 0;
1248 }
1249
1250 /* read the non-space input */
1251 while (cnt && !isspace(ch)) {
1252 if (parser->idx < parser->size - 1)
1253 parser->buffer[parser->idx++] = ch;
1254 else {
1255 ret = -EINVAL;
1256 goto out;
1257 }
1258 ret = get_user(ch, ubuf++);
1259 if (ret)
1260 goto out;
1261 read++;
1262 cnt--;
1263 }
1264
1265 /* We either got finished input or we have to wait for another call. */
1266 if (isspace(ch)) {
1267 parser->buffer[parser->idx] = 0;
1268 parser->cont = false;
1269 } else if (parser->idx < parser->size - 1) {
1270 parser->cont = true;
1271 parser->buffer[parser->idx++] = ch;
1272 } else {
1273 ret = -EINVAL;
1274 goto out;
1275 }
1276
1277 *ppos += read;
1278 ret = read;
1279
1280out:
1281 return ret;
1282}
1283
1284/* TODO add a seq_buf_to_buffer() */
1285static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1286{
1287 int len;
1288
1289 if (trace_seq_used(s) <= s->seq.readpos)
1290 return -EBUSY;
1291
1292 len = trace_seq_used(s) - s->seq.readpos;
1293 if (cnt > len)
1294 cnt = len;
1295 memcpy(buf, s->buffer + s->seq.readpos, cnt);
1296
1297 s->seq.readpos += cnt;
1298 return cnt;
1299}
1300
1301unsigned long __read_mostly tracing_thresh;
1302
1303#ifdef CONFIG_TRACER_MAX_TRACE
1304/*
1305 * Copy the new maximum trace into the separate maximum-trace
1306 * structure. (this way the maximum trace is permanently saved,
1307 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
1308 */
1309static void
1310__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1311{
1312 struct trace_buffer *trace_buf = &tr->trace_buffer;
1313 struct trace_buffer *max_buf = &tr->max_buffer;
1314 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1315 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1316
1317 max_buf->cpu = cpu;
1318 max_buf->time_start = data->preempt_timestamp;
1319
1320 max_data->saved_latency = tr->max_latency;
1321 max_data->critical_start = data->critical_start;
1322 max_data->critical_end = data->critical_end;
1323
1324 memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1325 max_data->pid = tsk->pid;
1326 /*
1327 * If tsk == current, then use current_uid(), as that does not use
1328 * RCU. The irq tracer can be called out of RCU scope.
1329 */
1330 if (tsk == current)
1331 max_data->uid = current_uid();
1332 else
1333 max_data->uid = task_uid(tsk);
1334
1335 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1336 max_data->policy = tsk->policy;
1337 max_data->rt_priority = tsk->rt_priority;
1338
1339 /* record this tasks comm */
1340 tracing_record_cmdline(tsk);
1341}
1342
1343/**
1344 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1345 * @tr: tracer
1346 * @tsk: the task with the latency
1347 * @cpu: The cpu that initiated the trace.
1348 *
1349 * Flip the buffers between the @tr and the max_tr and record information
1350 * about which task was the cause of this latency.
1351 */
1352void
1353update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1354{
1355 struct ring_buffer *buf;
1356
1357 if (tr->stop_count)
1358 return;
1359
1360 WARN_ON_ONCE(!irqs_disabled());
1361
1362 if (!tr->allocated_snapshot) {
1363 /* Only the nop tracer should hit this when disabling */
1364 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1365 return;
1366 }
1367
1368 arch_spin_lock(&tr->max_lock);
1369
1370 buf = tr->trace_buffer.buffer;
1371 tr->trace_buffer.buffer = tr->max_buffer.buffer;
1372 tr->max_buffer.buffer = buf;
1373
1374 __update_max_tr(tr, tsk, cpu);
1375 arch_spin_unlock(&tr->max_lock);
1376}
1377
1378/**
1379 * update_max_tr_single - only copy one trace over, and reset the rest
1380 * @tr - tracer
1381 * @tsk - task with the latency
1382 * @cpu - the cpu of the buffer to copy.
1383 *
1384 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1385 */
1386void
1387update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1388{
1389 int ret;
1390
1391 if (tr->stop_count)
1392 return;
1393
1394 WARN_ON_ONCE(!irqs_disabled());
1395 if (!tr->allocated_snapshot) {
1396 /* Only the nop tracer should hit this when disabling */
1397 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1398 return;
1399 }
1400
1401 arch_spin_lock(&tr->max_lock);
1402
1403 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
1404
1405 if (ret == -EBUSY) {
1406 /*
1407 * We failed to swap the buffer due to a commit taking
1408 * place on this CPU. We fail to record, but we reset
1409 * the max trace buffer (no one writes directly to it)
1410 * and flag that it failed.
1411 */
1412 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1413 "Failed to swap buffers due to commit in progress\n");
1414 }
1415
1416 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1417
1418 __update_max_tr(tr, tsk, cpu);
1419 arch_spin_unlock(&tr->max_lock);
1420}
1421#endif /* CONFIG_TRACER_MAX_TRACE */
1422
1423static int wait_on_pipe(struct trace_iterator *iter, bool full)
1424{
1425 /* Iterators are static, they should be filled or empty */
1426 if (trace_buffer_iter(iter, iter->cpu_file))
1427 return 0;
1428
1429 return ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file,
1430 full);
1431}
1432
1433#ifdef CONFIG_FTRACE_STARTUP_TEST
1434static int run_tracer_selftest(struct tracer *type)
1435{
1436 struct trace_array *tr = &global_trace;
1437 struct tracer *saved_tracer = tr->current_trace;
1438 int ret;
1439
1440 if (!type->selftest || tracing_selftest_disabled)
1441 return 0;
1442
1443 /*
1444 * Run a selftest on this tracer.
1445 * Here we reset the trace buffer, and set the current
1446 * tracer to be this tracer. The tracer can then run some
1447 * internal tracing to verify that everything is in order.
1448 * If we fail, we do not register this tracer.
1449 */
1450 tracing_reset_online_cpus(&tr->trace_buffer);
1451
1452 tr->current_trace = type;
1453
1454#ifdef CONFIG_TRACER_MAX_TRACE
1455 if (type->use_max_tr) {
1456 /* If we expanded the buffers, make sure the max is expanded too */
1457 if (ring_buffer_expanded)
1458 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
1459 RING_BUFFER_ALL_CPUS);
1460 tr->allocated_snapshot = true;
1461 }
1462#endif
1463
1464 /* the test is responsible for initializing and enabling */
1465 pr_info("Testing tracer %s: ", type->name);
1466 ret = type->selftest(type, tr);
1467 /* the test is responsible for resetting too */
1468 tr->current_trace = saved_tracer;
1469 if (ret) {
1470 printk(KERN_CONT "FAILED!\n");
1471 /* Add the warning after printing 'FAILED' */
1472 WARN_ON(1);
1473 return -1;
1474 }
1475 /* Only reset on passing, to avoid touching corrupted buffers */
1476 tracing_reset_online_cpus(&tr->trace_buffer);
1477
1478#ifdef CONFIG_TRACER_MAX_TRACE
1479 if (type->use_max_tr) {
1480 tr->allocated_snapshot = false;
1481
1482 /* Shrink the max buffer again */
1483 if (ring_buffer_expanded)
1484 ring_buffer_resize(tr->max_buffer.buffer, 1,
1485 RING_BUFFER_ALL_CPUS);
1486 }
1487#endif
1488
1489 printk(KERN_CONT "PASSED\n");
1490 return 0;
1491}
1492#else
1493static inline int run_tracer_selftest(struct tracer *type)
1494{
1495 return 0;
1496}
1497#endif /* CONFIG_FTRACE_STARTUP_TEST */
1498
1499static void add_tracer_options(struct trace_array *tr, struct tracer *t);
1500
1501static void __init apply_trace_boot_options(void);
1502
1503/**
1504 * register_tracer - register a tracer with the ftrace system.
1505 * @type - the plugin for the tracer
1506 *
1507 * Register a new plugin tracer.
1508 */
1509int __init register_tracer(struct tracer *type)
1510{
1511 struct tracer *t;
1512 int ret = 0;
1513
1514 if (!type->name) {
1515 pr_info("Tracer must have a name\n");
1516 return -1;
1517 }
1518
1519 if (strlen(type->name) >= MAX_TRACER_SIZE) {
1520 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
1521 return -1;
1522 }
1523
1524 mutex_lock(&trace_types_lock);
1525
1526 tracing_selftest_running = true;
1527
1528 for (t = trace_types; t; t = t->next) {
1529 if (strcmp(type->name, t->name) == 0) {
1530 /* already found */
1531 pr_info("Tracer %s already registered\n",
1532 type->name);
1533 ret = -1;
1534 goto out;
1535 }
1536 }
1537
1538 if (!type->set_flag)
1539 type->set_flag = &dummy_set_flag;
1540 if (!type->flags) {
1541 /*allocate a dummy tracer_flags*/
1542 type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
1543 if (!type->flags) {
1544 ret = -ENOMEM;
1545 goto out;
1546 }
1547 type->flags->val = 0;
1548 type->flags->opts = dummy_tracer_opt;
1549 } else
1550 if (!type->flags->opts)
1551 type->flags->opts = dummy_tracer_opt;
1552
1553 /* store the tracer for __set_tracer_option */
1554 type->flags->trace = type;
1555
1556 ret = run_tracer_selftest(type);
1557 if (ret < 0)
1558 goto out;
1559
1560 type->next = trace_types;
1561 trace_types = type;
1562 add_tracer_options(&global_trace, type);
1563
1564 out:
1565 tracing_selftest_running = false;
1566 mutex_unlock(&trace_types_lock);
1567
1568 if (ret || !default_bootup_tracer)
1569 goto out_unlock;
1570
1571 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
1572 goto out_unlock;
1573
1574 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
1575 /* Do we want this tracer to start on bootup? */
1576 tracing_set_tracer(&global_trace, type->name);
1577 default_bootup_tracer = NULL;
1578
1579 apply_trace_boot_options();
1580
1581 /* disable other selftests, since this will break it. */
1582 tracing_selftest_disabled = true;
1583#ifdef CONFIG_FTRACE_STARTUP_TEST
1584 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
1585 type->name);
1586#endif
1587
1588 out_unlock:
1589 return ret;
1590}
1591
1592void tracing_reset(struct trace_buffer *buf, int cpu)
1593{
1594 struct ring_buffer *buffer = buf->buffer;
1595
1596 if (!buffer)
1597 return;
1598
1599 ring_buffer_record_disable(buffer);
1600
1601 /* Make sure all commits have finished */
1602 synchronize_sched();
1603 ring_buffer_reset_cpu(buffer, cpu);
1604
1605 ring_buffer_record_enable(buffer);
1606}
1607
1608void tracing_reset_online_cpus(struct trace_buffer *buf)
1609{
1610 struct ring_buffer *buffer = buf->buffer;
1611 int cpu;
1612
1613 if (!buffer)
1614 return;
1615
1616 ring_buffer_record_disable(buffer);
1617
1618 /* Make sure all commits have finished */
1619 synchronize_sched();
1620
1621 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
1622
1623 for_each_online_cpu(cpu)
1624 ring_buffer_reset_cpu(buffer, cpu);
1625
1626 ring_buffer_record_enable(buffer);
1627}
1628
1629/* Must have trace_types_lock held */
1630void tracing_reset_all_online_cpus(void)
1631{
1632 struct trace_array *tr;
1633
1634 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1635 tracing_reset_online_cpus(&tr->trace_buffer);
1636#ifdef CONFIG_TRACER_MAX_TRACE
1637 tracing_reset_online_cpus(&tr->max_buffer);
1638#endif
1639 }
1640}
1641
1642#define SAVED_CMDLINES_DEFAULT 128
1643#define NO_CMDLINE_MAP UINT_MAX
1644static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1645struct saved_cmdlines_buffer {
1646 unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
1647 unsigned *map_cmdline_to_pid;
1648 unsigned cmdline_num;
1649 int cmdline_idx;
1650 char *saved_cmdlines;
1651};
1652static struct saved_cmdlines_buffer *savedcmd;
1653
1654/* temporary disable recording */
1655static atomic_t trace_record_cmdline_disabled __read_mostly;
1656
1657static inline char *get_saved_cmdlines(int idx)
1658{
1659 return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
1660}
1661
1662static inline void set_cmdline(int idx, const char *cmdline)
1663{
1664 memcpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
1665}
1666
1667static int allocate_cmdlines_buffer(unsigned int val,
1668 struct saved_cmdlines_buffer *s)
1669{
1670 s->map_cmdline_to_pid = kmalloc(val * sizeof(*s->map_cmdline_to_pid),
1671 GFP_KERNEL);
1672 if (!s->map_cmdline_to_pid)
1673 return -ENOMEM;
1674
1675 s->saved_cmdlines = kmalloc(val * TASK_COMM_LEN, GFP_KERNEL);
1676 if (!s->saved_cmdlines) {
1677 kfree(s->map_cmdline_to_pid);
1678 return -ENOMEM;
1679 }
1680
1681 s->cmdline_idx = 0;
1682 s->cmdline_num = val;
1683 memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
1684 sizeof(s->map_pid_to_cmdline));
1685 memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
1686 val * sizeof(*s->map_cmdline_to_pid));
1687
1688 return 0;
1689}
1690
1691static int trace_create_savedcmd(void)
1692{
1693 int ret;
1694
1695 savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
1696 if (!savedcmd)
1697 return -ENOMEM;
1698
1699 ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
1700 if (ret < 0) {
1701 kfree(savedcmd);
1702 savedcmd = NULL;
1703 return -ENOMEM;
1704 }
1705
1706 return 0;
1707}
1708
1709int is_tracing_stopped(void)
1710{
1711 return global_trace.stop_count;
1712}
1713
1714/**
1715 * tracing_start - quick start of the tracer
1716 *
1717 * If tracing is enabled but was stopped by tracing_stop,
1718 * this will start the tracer back up.
1719 */
1720void tracing_start(void)
1721{
1722 struct ring_buffer *buffer;
1723 unsigned long flags;
1724
1725 if (tracing_disabled)
1726 return;
1727
1728 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1729 if (--global_trace.stop_count) {
1730 if (global_trace.stop_count < 0) {
1731 /* Someone screwed up their debugging */
1732 WARN_ON_ONCE(1);
1733 global_trace.stop_count = 0;
1734 }
1735 goto out;
1736 }
1737
1738 /* Prevent the buffers from switching */
1739 arch_spin_lock(&global_trace.max_lock);
1740
1741 buffer = global_trace.trace_buffer.buffer;
1742 if (buffer)
1743 ring_buffer_record_enable(buffer);
1744
1745#ifdef CONFIG_TRACER_MAX_TRACE
1746 buffer = global_trace.max_buffer.buffer;
1747 if (buffer)
1748 ring_buffer_record_enable(buffer);
1749#endif
1750
1751 arch_spin_unlock(&global_trace.max_lock);
1752
1753 out:
1754 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1755}
1756
1757static void tracing_start_tr(struct trace_array *tr)
1758{
1759 struct ring_buffer *buffer;
1760 unsigned long flags;
1761
1762 if (tracing_disabled)
1763 return;
1764
1765 /* If global, we need to also start the max tracer */
1766 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1767 return tracing_start();
1768
1769 raw_spin_lock_irqsave(&tr->start_lock, flags);
1770
1771 if (--tr->stop_count) {
1772 if (tr->stop_count < 0) {
1773 /* Someone screwed up their debugging */
1774 WARN_ON_ONCE(1);
1775 tr->stop_count = 0;
1776 }
1777 goto out;
1778 }
1779
1780 buffer = tr->trace_buffer.buffer;
1781 if (buffer)
1782 ring_buffer_record_enable(buffer);
1783
1784 out:
1785 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1786}
1787
1788/**
1789 * tracing_stop - quick stop of the tracer
1790 *
1791 * Light weight way to stop tracing. Use in conjunction with
1792 * tracing_start.
1793 */
1794void tracing_stop(void)
1795{
1796 struct ring_buffer *buffer;
1797 unsigned long flags;
1798
1799 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1800 if (global_trace.stop_count++)
1801 goto out;
1802
1803 /* Prevent the buffers from switching */
1804 arch_spin_lock(&global_trace.max_lock);
1805
1806 buffer = global_trace.trace_buffer.buffer;
1807 if (buffer)
1808 ring_buffer_record_disable(buffer);
1809
1810#ifdef CONFIG_TRACER_MAX_TRACE
1811 buffer = global_trace.max_buffer.buffer;
1812 if (buffer)
1813 ring_buffer_record_disable(buffer);
1814#endif
1815
1816 arch_spin_unlock(&global_trace.max_lock);
1817
1818 out:
1819 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1820}
1821
1822static void tracing_stop_tr(struct trace_array *tr)
1823{
1824 struct ring_buffer *buffer;
1825 unsigned long flags;
1826
1827 /* If global, we need to also stop the max tracer */
1828 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1829 return tracing_stop();
1830
1831 raw_spin_lock_irqsave(&tr->start_lock, flags);
1832 if (tr->stop_count++)
1833 goto out;
1834
1835 buffer = tr->trace_buffer.buffer;
1836 if (buffer)
1837 ring_buffer_record_disable(buffer);
1838
1839 out:
1840 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1841}
1842
1843void trace_stop_cmdline_recording(void);
1844
1845static int trace_save_cmdline(struct task_struct *tsk)
1846{
1847 unsigned pid, idx;
1848
1849 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
1850 return 0;
1851
1852 /*
1853 * It's not the end of the world if we don't get
1854 * the lock, but we also don't want to spin
1855 * nor do we want to disable interrupts,
1856 * so if we miss here, then better luck next time.
1857 */
1858 if (!arch_spin_trylock(&trace_cmdline_lock))
1859 return 0;
1860
1861 idx = savedcmd->map_pid_to_cmdline[tsk->pid];
1862 if (idx == NO_CMDLINE_MAP) {
1863 idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
1864
1865 /*
1866 * Check whether the cmdline buffer at idx has a pid
1867 * mapped. We are going to overwrite that entry so we
1868 * need to clear the map_pid_to_cmdline. Otherwise we
1869 * would read the new comm for the old pid.
1870 */
1871 pid = savedcmd->map_cmdline_to_pid[idx];
1872 if (pid != NO_CMDLINE_MAP)
1873 savedcmd->map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
1874
1875 savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
1876 savedcmd->map_pid_to_cmdline[tsk->pid] = idx;
1877
1878 savedcmd->cmdline_idx = idx;
1879 }
1880
1881 set_cmdline(idx, tsk->comm);
1882
1883 arch_spin_unlock(&trace_cmdline_lock);
1884
1885 return 1;
1886}
1887
1888static void __trace_find_cmdline(int pid, char comm[])
1889{
1890 unsigned map;
1891
1892 if (!pid) {
1893 strcpy(comm, "<idle>");
1894 return;
1895 }
1896
1897 if (WARN_ON_ONCE(pid < 0)) {
1898 strcpy(comm, "<XXX>");
1899 return;
1900 }
1901
1902 if (pid > PID_MAX_DEFAULT) {
1903 strcpy(comm, "<...>");
1904 return;
1905 }
1906
1907 map = savedcmd->map_pid_to_cmdline[pid];
1908 if (map != NO_CMDLINE_MAP)
1909 strcpy(comm, get_saved_cmdlines(map));
1910 else
1911 strcpy(comm, "<...>");
1912}
1913
1914void trace_find_cmdline(int pid, char comm[])
1915{
1916 preempt_disable();
1917 arch_spin_lock(&trace_cmdline_lock);
1918
1919 __trace_find_cmdline(pid, comm);
1920
1921 arch_spin_unlock(&trace_cmdline_lock);
1922 preempt_enable();
1923}
1924
1925void tracing_record_cmdline(struct task_struct *tsk)
1926{
1927 if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
1928 return;
1929
1930 if (!__this_cpu_read(trace_cmdline_save))
1931 return;
1932
1933 if (trace_save_cmdline(tsk))
1934 __this_cpu_write(trace_cmdline_save, false);
1935}
1936
1937void
1938tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
1939 int pc)
1940{
1941 struct task_struct *tsk = current;
1942
1943 entry->preempt_count = pc & 0xff;
1944 entry->pid = (tsk) ? tsk->pid : 0;
1945 entry->flags =
1946#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1947 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
1948#else
1949 TRACE_FLAG_IRQS_NOSUPPORT |
1950#endif
1951 ((pc & NMI_MASK ) ? TRACE_FLAG_NMI : 0) |
1952 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
1953 ((pc & SOFTIRQ_OFFSET) ? TRACE_FLAG_SOFTIRQ : 0) |
1954 (tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
1955 (test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
1956}
1957EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
1958
1959struct ring_buffer_event *
1960trace_buffer_lock_reserve(struct ring_buffer *buffer,
1961 int type,
1962 unsigned long len,
1963 unsigned long flags, int pc)
1964{
1965 return __trace_buffer_lock_reserve(buffer, type, len, flags, pc);
1966}
1967
1968DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
1969DEFINE_PER_CPU(int, trace_buffered_event_cnt);
1970static int trace_buffered_event_ref;
1971
1972/**
1973 * trace_buffered_event_enable - enable buffering events
1974 *
1975 * When events are being filtered, it is quicker to use a temporary
1976 * buffer to write the event data into if there's a likely chance
1977 * that it will not be committed. The discard of the ring buffer
1978 * is not as fast as committing, and is much slower than copying
1979 * a commit.
1980 *
1981 * When an event is to be filtered, allocate per cpu buffers to
1982 * write the event data into, and if the event is filtered and discarded
1983 * it is simply dropped, otherwise, the entire data is to be committed
1984 * in one shot.
1985 */
1986void trace_buffered_event_enable(void)
1987{
1988 struct ring_buffer_event *event;
1989 struct page *page;
1990 int cpu;
1991
1992 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
1993
1994 if (trace_buffered_event_ref++)
1995 return;
1996
1997 for_each_tracing_cpu(cpu) {
1998 page = alloc_pages_node(cpu_to_node(cpu),
1999 GFP_KERNEL | __GFP_NORETRY, 0);
2000 if (!page)
2001 goto failed;
2002
2003 event = page_address(page);
2004 memset(event, 0, sizeof(*event));
2005
2006 per_cpu(trace_buffered_event, cpu) = event;
2007
2008 preempt_disable();
2009 if (cpu == smp_processor_id() &&
2010 this_cpu_read(trace_buffered_event) !=
2011 per_cpu(trace_buffered_event, cpu))
2012 WARN_ON_ONCE(1);
2013 preempt_enable();
2014 }
2015
2016 return;
2017 failed:
2018 trace_buffered_event_disable();
2019}
2020
2021static void enable_trace_buffered_event(void *data)
2022{
2023 /* Probably not needed, but do it anyway */
2024 smp_rmb();
2025 this_cpu_dec(trace_buffered_event_cnt);
2026}
2027
2028static void disable_trace_buffered_event(void *data)
2029{
2030 this_cpu_inc(trace_buffered_event_cnt);
2031}
2032
2033/**
2034 * trace_buffered_event_disable - disable buffering events
2035 *
2036 * When a filter is removed, it is faster to not use the buffered
2037 * events, and to commit directly into the ring buffer. Free up
2038 * the temp buffers when there are no more users. This requires
2039 * special synchronization with current events.
2040 */
2041void trace_buffered_event_disable(void)
2042{
2043 int cpu;
2044
2045 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2046
2047 if (WARN_ON_ONCE(!trace_buffered_event_ref))
2048 return;
2049
2050 if (--trace_buffered_event_ref)
2051 return;
2052
2053 preempt_disable();
2054 /* For each CPU, set the buffer as used. */
2055 smp_call_function_many(tracing_buffer_mask,
2056 disable_trace_buffered_event, NULL, 1);
2057 preempt_enable();
2058
2059 /* Wait for all current users to finish */
2060 synchronize_sched();
2061
2062 for_each_tracing_cpu(cpu) {
2063 free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
2064 per_cpu(trace_buffered_event, cpu) = NULL;
2065 }
2066 /*
2067 * Make sure trace_buffered_event is NULL before clearing
2068 * trace_buffered_event_cnt.
2069 */
2070 smp_wmb();
2071
2072 preempt_disable();
2073 /* Do the work on each cpu */
2074 smp_call_function_many(tracing_buffer_mask,
2075 enable_trace_buffered_event, NULL, 1);
2076 preempt_enable();
2077}
2078
2079static struct ring_buffer *temp_buffer;
2080
2081struct ring_buffer_event *
2082trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
2083 struct trace_event_file *trace_file,
2084 int type, unsigned long len,
2085 unsigned long flags, int pc)
2086{
2087 struct ring_buffer_event *entry;
2088 int val;
2089
2090 *current_rb = trace_file->tr->trace_buffer.buffer;
2091
2092 if ((trace_file->flags &
2093 (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
2094 (entry = this_cpu_read(trace_buffered_event))) {
2095 /* Try to use the per cpu buffer first */
2096 val = this_cpu_inc_return(trace_buffered_event_cnt);
2097 if (val == 1) {
2098 trace_event_setup(entry, type, flags, pc);
2099 entry->array[0] = len;
2100 return entry;
2101 }
2102 this_cpu_dec(trace_buffered_event_cnt);
2103 }
2104
2105 entry = __trace_buffer_lock_reserve(*current_rb,
2106 type, len, flags, pc);
2107 /*
2108 * If tracing is off, but we have triggers enabled
2109 * we still need to look at the event data. Use the temp_buffer
2110 * to store the trace event for the tigger to use. It's recusive
2111 * safe and will not be recorded anywhere.
2112 */
2113 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
2114 *current_rb = temp_buffer;
2115 entry = __trace_buffer_lock_reserve(*current_rb,
2116 type, len, flags, pc);
2117 }
2118 return entry;
2119}
2120EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
2121
2122static DEFINE_SPINLOCK(tracepoint_iter_lock);
2123static DEFINE_MUTEX(tracepoint_printk_mutex);
2124
2125static void output_printk(struct trace_event_buffer *fbuffer)
2126{
2127 struct trace_event_call *event_call;
2128 struct trace_event *event;
2129 unsigned long flags;
2130 struct trace_iterator *iter = tracepoint_print_iter;
2131
2132 /* We should never get here if iter is NULL */
2133 if (WARN_ON_ONCE(!iter))
2134 return;
2135
2136 event_call = fbuffer->trace_file->event_call;
2137 if (!event_call || !event_call->event.funcs ||
2138 !event_call->event.funcs->trace)
2139 return;
2140
2141 event = &fbuffer->trace_file->event_call->event;
2142
2143 spin_lock_irqsave(&tracepoint_iter_lock, flags);
2144 trace_seq_init(&iter->seq);
2145 iter->ent = fbuffer->entry;
2146 event_call->event.funcs->trace(iter, 0, event);
2147 trace_seq_putc(&iter->seq, 0);
2148 printk("%s", iter->seq.buffer);
2149
2150 spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
2151}
2152
2153int tracepoint_printk_sysctl(struct ctl_table *table, int write,
2154 void __user *buffer, size_t *lenp,
2155 loff_t *ppos)
2156{
2157 int save_tracepoint_printk;
2158 int ret;
2159
2160 mutex_lock(&tracepoint_printk_mutex);
2161 save_tracepoint_printk = tracepoint_printk;
2162
2163 ret = proc_dointvec(table, write, buffer, lenp, ppos);
2164
2165 /*
2166 * This will force exiting early, as tracepoint_printk
2167 * is always zero when tracepoint_printk_iter is not allocated
2168 */
2169 if (!tracepoint_print_iter)
2170 tracepoint_printk = 0;
2171
2172 if (save_tracepoint_printk == tracepoint_printk)
2173 goto out;
2174
2175 if (tracepoint_printk)
2176 static_key_enable(&tracepoint_printk_key.key);
2177 else
2178 static_key_disable(&tracepoint_printk_key.key);
2179
2180 out:
2181 mutex_unlock(&tracepoint_printk_mutex);
2182
2183 return ret;
2184}
2185
2186void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
2187{
2188 if (static_key_false(&tracepoint_printk_key.key))
2189 output_printk(fbuffer);
2190
2191 event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer,
2192 fbuffer->event, fbuffer->entry,
2193 fbuffer->flags, fbuffer->pc);
2194}
2195EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
2196
2197void trace_buffer_unlock_commit_regs(struct trace_array *tr,
2198 struct ring_buffer *buffer,
2199 struct ring_buffer_event *event,
2200 unsigned long flags, int pc,
2201 struct pt_regs *regs)
2202{
2203 __buffer_unlock_commit(buffer, event);
2204
2205 /*
2206 * If regs is not set, then skip the following callers:
2207 * trace_buffer_unlock_commit_regs
2208 * event_trigger_unlock_commit
2209 * trace_event_buffer_commit
2210 * trace_event_raw_event_sched_switch
2211 * Note, we can still get here via blktrace, wakeup tracer
2212 * and mmiotrace, but that's ok if they lose a function or
2213 * two. They are that meaningful.
2214 */
2215 ftrace_trace_stack(tr, buffer, flags, regs ? 0 : 4, pc, regs);
2216 ftrace_trace_userstack(buffer, flags, pc);
2217}
2218
2219/*
2220 * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
2221 */
2222void
2223trace_buffer_unlock_commit_nostack(struct ring_buffer *buffer,
2224 struct ring_buffer_event *event)
2225{
2226 __buffer_unlock_commit(buffer, event);
2227}
2228
2229static void
2230trace_process_export(struct trace_export *export,
2231 struct ring_buffer_event *event)
2232{
2233 struct trace_entry *entry;
2234 unsigned int size = 0;
2235
2236 entry = ring_buffer_event_data(event);
2237 size = ring_buffer_event_length(event);
2238 export->write(entry, size);
2239}
2240
2241static DEFINE_MUTEX(ftrace_export_lock);
2242
2243static struct trace_export __rcu *ftrace_exports_list __read_mostly;
2244
2245static DEFINE_STATIC_KEY_FALSE(ftrace_exports_enabled);
2246
2247static inline void ftrace_exports_enable(void)
2248{
2249 static_branch_enable(&ftrace_exports_enabled);
2250}
2251
2252static inline void ftrace_exports_disable(void)
2253{
2254 static_branch_disable(&ftrace_exports_enabled);
2255}
2256
2257void ftrace_exports(struct ring_buffer_event *event)
2258{
2259 struct trace_export *export;
2260
2261 preempt_disable_notrace();
2262
2263 export = rcu_dereference_raw_notrace(ftrace_exports_list);
2264 while (export) {
2265 trace_process_export(export, event);
2266 export = rcu_dereference_raw_notrace(export->next);
2267 }
2268
2269 preempt_enable_notrace();
2270}
2271
2272static inline void
2273add_trace_export(struct trace_export **list, struct trace_export *export)
2274{
2275 rcu_assign_pointer(export->next, *list);
2276 /*
2277 * We are entering export into the list but another
2278 * CPU might be walking that list. We need to make sure
2279 * the export->next pointer is valid before another CPU sees
2280 * the export pointer included into the list.
2281 */
2282 rcu_assign_pointer(*list, export);
2283}
2284
2285static inline int
2286rm_trace_export(struct trace_export **list, struct trace_export *export)
2287{
2288 struct trace_export **p;
2289
2290 for (p = list; *p != NULL; p = &(*p)->next)
2291 if (*p == export)
2292 break;
2293
2294 if (*p != export)
2295 return -1;
2296
2297 rcu_assign_pointer(*p, (*p)->next);
2298
2299 return 0;
2300}
2301
2302static inline void
2303add_ftrace_export(struct trace_export **list, struct trace_export *export)
2304{
2305 if (*list == NULL)
2306 ftrace_exports_enable();
2307
2308 add_trace_export(list, export);
2309}
2310
2311static inline int
2312rm_ftrace_export(struct trace_export **list, struct trace_export *export)
2313{
2314 int ret;
2315
2316 ret = rm_trace_export(list, export);
2317 if (*list == NULL)
2318 ftrace_exports_disable();
2319
2320 return ret;
2321}
2322
2323int register_ftrace_export(struct trace_export *export)
2324{
2325 if (WARN_ON_ONCE(!export->write))
2326 return -1;
2327
2328 mutex_lock(&ftrace_export_lock);
2329
2330 add_ftrace_export(&ftrace_exports_list, export);
2331
2332 mutex_unlock(&ftrace_export_lock);
2333
2334 return 0;
2335}
2336EXPORT_SYMBOL_GPL(register_ftrace_export);
2337
2338int unregister_ftrace_export(struct trace_export *export)
2339{
2340 int ret;
2341
2342 mutex_lock(&ftrace_export_lock);
2343
2344 ret = rm_ftrace_export(&ftrace_exports_list, export);
2345
2346 mutex_unlock(&ftrace_export_lock);
2347
2348 return ret;
2349}
2350EXPORT_SYMBOL_GPL(unregister_ftrace_export);
2351
2352void
2353trace_function(struct trace_array *tr,
2354 unsigned long ip, unsigned long parent_ip, unsigned long flags,
2355 int pc)
2356{
2357 struct trace_event_call *call = &event_function;
2358 struct ring_buffer *buffer = tr->trace_buffer.buffer;
2359 struct ring_buffer_event *event;
2360 struct ftrace_entry *entry;
2361
2362 event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
2363 flags, pc);
2364 if (!event)
2365 return;
2366 entry = ring_buffer_event_data(event);
2367 entry->ip = ip;
2368 entry->parent_ip = parent_ip;
2369
2370 if (!call_filter_check_discard(call, entry, buffer, event)) {
2371 if (static_branch_unlikely(&ftrace_exports_enabled))
2372 ftrace_exports(event);
2373 __buffer_unlock_commit(buffer, event);
2374 }
2375}
2376
2377#ifdef CONFIG_STACKTRACE
2378
2379#define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
2380struct ftrace_stack {
2381 unsigned long calls[FTRACE_STACK_MAX_ENTRIES];
2382};
2383
2384static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
2385static DEFINE_PER_CPU(int, ftrace_stack_reserve);
2386
2387static void __ftrace_trace_stack(struct ring_buffer *buffer,
2388 unsigned long flags,
2389 int skip, int pc, struct pt_regs *regs)
2390{
2391 struct trace_event_call *call = &event_kernel_stack;
2392 struct ring_buffer_event *event;
2393 struct stack_entry *entry;
2394 struct stack_trace trace;
2395 int use_stack;
2396 int size = FTRACE_STACK_ENTRIES;
2397
2398 trace.nr_entries = 0;
2399 trace.skip = skip;
2400
2401 /*
2402 * Add two, for this function and the call to save_stack_trace()
2403 * If regs is set, then these functions will not be in the way.
2404 */
2405 if (!regs)
2406 trace.skip += 2;
2407
2408 /*
2409 * Since events can happen in NMIs there's no safe way to
2410 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
2411 * or NMI comes in, it will just have to use the default
2412 * FTRACE_STACK_SIZE.
2413 */
2414 preempt_disable_notrace();
2415
2416 use_stack = __this_cpu_inc_return(ftrace_stack_reserve);
2417 /*
2418 * We don't need any atomic variables, just a barrier.
2419 * If an interrupt comes in, we don't care, because it would
2420 * have exited and put the counter back to what we want.
2421 * We just need a barrier to keep gcc from moving things
2422 * around.
2423 */
2424 barrier();
2425 if (use_stack == 1) {
2426 trace.entries = this_cpu_ptr(ftrace_stack.calls);
2427 trace.max_entries = FTRACE_STACK_MAX_ENTRIES;
2428
2429 if (regs)
2430 save_stack_trace_regs(regs, &trace);
2431 else
2432 save_stack_trace(&trace);
2433
2434 if (trace.nr_entries > size)
2435 size = trace.nr_entries;
2436 } else
2437 /* From now on, use_stack is a boolean */
2438 use_stack = 0;
2439
2440 size *= sizeof(unsigned long);
2441
2442 event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
2443 sizeof(*entry) + size, flags, pc);
2444 if (!event)
2445 goto out;
2446 entry = ring_buffer_event_data(event);
2447
2448 memset(&entry->caller, 0, size);
2449
2450 if (use_stack)
2451 memcpy(&entry->caller, trace.entries,
2452 trace.nr_entries * sizeof(unsigned long));
2453 else {
2454 trace.max_entries = FTRACE_STACK_ENTRIES;
2455 trace.entries = entry->caller;
2456 if (regs)
2457 save_stack_trace_regs(regs, &trace);
2458 else
2459 save_stack_trace(&trace);
2460 }
2461
2462 entry->size = trace.nr_entries;
2463
2464 if (!call_filter_check_discard(call, entry, buffer, event))
2465 __buffer_unlock_commit(buffer, event);
2466
2467 out:
2468 /* Again, don't let gcc optimize things here */
2469 barrier();
2470 __this_cpu_dec(ftrace_stack_reserve);
2471 preempt_enable_notrace();
2472
2473}
2474
2475static inline void ftrace_trace_stack(struct trace_array *tr,
2476 struct ring_buffer *buffer,
2477 unsigned long flags,
2478 int skip, int pc, struct pt_regs *regs)
2479{
2480 if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
2481 return;
2482
2483 __ftrace_trace_stack(buffer, flags, skip, pc, regs);
2484}
2485
2486void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
2487 int pc)
2488{
2489 __ftrace_trace_stack(tr->trace_buffer.buffer, flags, skip, pc, NULL);
2490}
2491
2492/**
2493 * trace_dump_stack - record a stack back trace in the trace buffer
2494 * @skip: Number of functions to skip (helper handlers)
2495 */
2496void trace_dump_stack(int skip)
2497{
2498 unsigned long flags;
2499
2500 if (tracing_disabled || tracing_selftest_running)
2501 return;
2502
2503 local_save_flags(flags);
2504
2505 /*
2506 * Skip 3 more, seems to get us at the caller of
2507 * this function.
2508 */
2509 skip += 3;
2510 __ftrace_trace_stack(global_trace.trace_buffer.buffer,
2511 flags, skip, preempt_count(), NULL);
2512}
2513
2514static DEFINE_PER_CPU(int, user_stack_count);
2515
2516void
2517ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
2518{
2519 struct trace_event_call *call = &event_user_stack;
2520 struct ring_buffer_event *event;
2521 struct userstack_entry *entry;
2522 struct stack_trace trace;
2523
2524 if (!(global_trace.trace_flags & TRACE_ITER_USERSTACKTRACE))
2525 return;
2526
2527 /*
2528 * NMIs can not handle page faults, even with fix ups.
2529 * The save user stack can (and often does) fault.
2530 */
2531 if (unlikely(in_nmi()))
2532 return;
2533
2534 /*
2535 * prevent recursion, since the user stack tracing may
2536 * trigger other kernel events.
2537 */
2538 preempt_disable();
2539 if (__this_cpu_read(user_stack_count))
2540 goto out;
2541
2542 __this_cpu_inc(user_stack_count);
2543
2544 event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
2545 sizeof(*entry), flags, pc);
2546 if (!event)
2547 goto out_drop_count;
2548 entry = ring_buffer_event_data(event);
2549
2550 entry->tgid = current->tgid;
2551 memset(&entry->caller, 0, sizeof(entry->caller));
2552
2553 trace.nr_entries = 0;
2554 trace.max_entries = FTRACE_STACK_ENTRIES;
2555 trace.skip = 0;
2556 trace.entries = entry->caller;
2557
2558 save_stack_trace_user(&trace);
2559 if (!call_filter_check_discard(call, entry, buffer, event))
2560 __buffer_unlock_commit(buffer, event);
2561
2562 out_drop_count:
2563 __this_cpu_dec(user_stack_count);
2564 out:
2565 preempt_enable();
2566}
2567
2568#ifdef UNUSED
2569static void __trace_userstack(struct trace_array *tr, unsigned long flags)
2570{
2571 ftrace_trace_userstack(tr, flags, preempt_count());
2572}
2573#endif /* UNUSED */
2574
2575#endif /* CONFIG_STACKTRACE */
2576
2577/* created for use with alloc_percpu */
2578struct trace_buffer_struct {
2579 int nesting;
2580 char buffer[4][TRACE_BUF_SIZE];
2581};
2582
2583static struct trace_buffer_struct *trace_percpu_buffer;
2584
2585/*
2586 * Thise allows for lockless recording. If we're nested too deeply, then
2587 * this returns NULL.
2588 */
2589static char *get_trace_buf(void)
2590{
2591 struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
2592
2593 if (!buffer || buffer->nesting >= 4)
2594 return NULL;
2595
2596 return &buffer->buffer[buffer->nesting++][0];
2597}
2598
2599static void put_trace_buf(void)
2600{
2601 this_cpu_dec(trace_percpu_buffer->nesting);
2602}
2603
2604static int alloc_percpu_trace_buffer(void)
2605{
2606 struct trace_buffer_struct *buffers;
2607
2608 buffers = alloc_percpu(struct trace_buffer_struct);
2609 if (WARN(!buffers, "Could not allocate percpu trace_printk buffer"))
2610 return -ENOMEM;
2611
2612 trace_percpu_buffer = buffers;
2613 return 0;
2614}
2615
2616static int buffers_allocated;
2617
2618void trace_printk_init_buffers(void)
2619{
2620 if (buffers_allocated)
2621 return;
2622
2623 if (alloc_percpu_trace_buffer())
2624 return;
2625
2626 /* trace_printk() is for debug use only. Don't use it in production. */
2627
2628 pr_warn("\n");
2629 pr_warn("**********************************************************\n");
2630 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
2631 pr_warn("** **\n");
2632 pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
2633 pr_warn("** **\n");
2634 pr_warn("** This means that this is a DEBUG kernel and it is **\n");
2635 pr_warn("** unsafe for production use. **\n");
2636 pr_warn("** **\n");
2637 pr_warn("** If you see this message and you are not debugging **\n");
2638 pr_warn("** the kernel, report this immediately to your vendor! **\n");
2639 pr_warn("** **\n");
2640 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
2641 pr_warn("**********************************************************\n");
2642
2643 /* Expand the buffers to set size */
2644 tracing_update_buffers();
2645
2646 buffers_allocated = 1;
2647
2648 /*
2649 * trace_printk_init_buffers() can be called by modules.
2650 * If that happens, then we need to start cmdline recording
2651 * directly here. If the global_trace.buffer is already
2652 * allocated here, then this was called by module code.
2653 */
2654 if (global_trace.trace_buffer.buffer)
2655 tracing_start_cmdline_record();
2656}
2657
2658void trace_printk_start_comm(void)
2659{
2660 /* Start tracing comms if trace printk is set */
2661 if (!buffers_allocated)
2662 return;
2663 tracing_start_cmdline_record();
2664}
2665
2666static void trace_printk_start_stop_comm(int enabled)
2667{
2668 if (!buffers_allocated)
2669 return;
2670
2671 if (enabled)
2672 tracing_start_cmdline_record();
2673 else
2674 tracing_stop_cmdline_record();
2675}
2676
2677/**
2678 * trace_vbprintk - write binary msg to tracing buffer
2679 *
2680 */
2681int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
2682{
2683 struct trace_event_call *call = &event_bprint;
2684 struct ring_buffer_event *event;
2685 struct ring_buffer *buffer;
2686 struct trace_array *tr = &global_trace;
2687 struct bprint_entry *entry;
2688 unsigned long flags;
2689 char *tbuffer;
2690 int len = 0, size, pc;
2691
2692 if (unlikely(tracing_selftest_running || tracing_disabled))
2693 return 0;
2694
2695 /* Don't pollute graph traces with trace_vprintk internals */
2696 pause_graph_tracing();
2697
2698 pc = preempt_count();
2699 preempt_disable_notrace();
2700
2701 tbuffer = get_trace_buf();
2702 if (!tbuffer) {
2703 len = 0;
2704 goto out_nobuffer;
2705 }
2706
2707 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
2708
2709 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
2710 goto out;
2711
2712 local_save_flags(flags);
2713 size = sizeof(*entry) + sizeof(u32) * len;
2714 buffer = tr->trace_buffer.buffer;
2715 event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
2716 flags, pc);
2717 if (!event)
2718 goto out;
2719 entry = ring_buffer_event_data(event);
2720 entry->ip = ip;
2721 entry->fmt = fmt;
2722
2723 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
2724 if (!call_filter_check_discard(call, entry, buffer, event)) {
2725 __buffer_unlock_commit(buffer, event);
2726 ftrace_trace_stack(tr, buffer, flags, 6, pc, NULL);
2727 }
2728
2729out:
2730 put_trace_buf();
2731
2732out_nobuffer:
2733 preempt_enable_notrace();
2734 unpause_graph_tracing();
2735
2736 return len;
2737}
2738EXPORT_SYMBOL_GPL(trace_vbprintk);
2739
2740static int
2741__trace_array_vprintk(struct ring_buffer *buffer,
2742 unsigned long ip, const char *fmt, va_list args)
2743{
2744 struct trace_event_call *call = &event_print;
2745 struct ring_buffer_event *event;
2746 int len = 0, size, pc;
2747 struct print_entry *entry;
2748 unsigned long flags;
2749 char *tbuffer;
2750
2751 if (tracing_disabled || tracing_selftest_running)
2752 return 0;
2753
2754 /* Don't pollute graph traces with trace_vprintk internals */
2755 pause_graph_tracing();
2756
2757 pc = preempt_count();
2758 preempt_disable_notrace();
2759
2760
2761 tbuffer = get_trace_buf();
2762 if (!tbuffer) {
2763 len = 0;
2764 goto out_nobuffer;
2765 }
2766
2767 len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
2768
2769 local_save_flags(flags);
2770 size = sizeof(*entry) + len + 1;
2771 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
2772 flags, pc);
2773 if (!event)
2774 goto out;
2775 entry = ring_buffer_event_data(event);
2776 entry->ip = ip;
2777
2778 memcpy(&entry->buf, tbuffer, len + 1);
2779 if (!call_filter_check_discard(call, entry, buffer, event)) {
2780 __buffer_unlock_commit(buffer, event);
2781 ftrace_trace_stack(&global_trace, buffer, flags, 6, pc, NULL);
2782 }
2783
2784out:
2785 put_trace_buf();
2786
2787out_nobuffer:
2788 preempt_enable_notrace();
2789 unpause_graph_tracing();
2790
2791 return len;
2792}
2793
2794int trace_array_vprintk(struct trace_array *tr,
2795 unsigned long ip, const char *fmt, va_list args)
2796{
2797 return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
2798}
2799
2800int trace_array_printk(struct trace_array *tr,
2801 unsigned long ip, const char *fmt, ...)
2802{
2803 int ret;
2804 va_list ap;
2805
2806 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
2807 return 0;
2808
2809 va_start(ap, fmt);
2810 ret = trace_array_vprintk(tr, ip, fmt, ap);
2811 va_end(ap);
2812 return ret;
2813}
2814
2815int trace_array_printk_buf(struct ring_buffer *buffer,
2816 unsigned long ip, const char *fmt, ...)
2817{
2818 int ret;
2819 va_list ap;
2820
2821 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
2822 return 0;
2823
2824 va_start(ap, fmt);
2825 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
2826 va_end(ap);
2827 return ret;
2828}
2829
2830int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
2831{
2832 return trace_array_vprintk(&global_trace, ip, fmt, args);
2833}
2834EXPORT_SYMBOL_GPL(trace_vprintk);
2835
2836static void trace_iterator_increment(struct trace_iterator *iter)
2837{
2838 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
2839
2840 iter->idx++;
2841 if (buf_iter)
2842 ring_buffer_read(buf_iter, NULL);
2843}
2844
2845static struct trace_entry *
2846peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
2847 unsigned long *lost_events)
2848{
2849 struct ring_buffer_event *event;
2850 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
2851
2852 if (buf_iter)
2853 event = ring_buffer_iter_peek(buf_iter, ts);
2854 else
2855 event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts,
2856 lost_events);
2857
2858 if (event) {
2859 iter->ent_size = ring_buffer_event_length(event);
2860 return ring_buffer_event_data(event);
2861 }
2862 iter->ent_size = 0;
2863 return NULL;
2864}
2865
2866static struct trace_entry *
2867__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
2868 unsigned long *missing_events, u64 *ent_ts)
2869{
2870 struct ring_buffer *buffer = iter->trace_buffer->buffer;
2871 struct trace_entry *ent, *next = NULL;
2872 unsigned long lost_events = 0, next_lost = 0;
2873 int cpu_file = iter->cpu_file;
2874 u64 next_ts = 0, ts;
2875 int next_cpu = -1;
2876 int next_size = 0;
2877 int cpu;
2878
2879 /*
2880 * If we are in a per_cpu trace file, don't bother by iterating over
2881 * all cpu and peek directly.
2882 */
2883 if (cpu_file > RING_BUFFER_ALL_CPUS) {
2884 if (ring_buffer_empty_cpu(buffer, cpu_file))
2885 return NULL;
2886 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
2887 if (ent_cpu)
2888 *ent_cpu = cpu_file;
2889
2890 return ent;
2891 }
2892
2893 for_each_tracing_cpu(cpu) {
2894
2895 if (ring_buffer_empty_cpu(buffer, cpu))
2896 continue;
2897
2898 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
2899
2900 /*
2901 * Pick the entry with the smallest timestamp:
2902 */
2903 if (ent && (!next || ts < next_ts)) {
2904 next = ent;
2905 next_cpu = cpu;
2906 next_ts = ts;
2907 next_lost = lost_events;
2908 next_size = iter->ent_size;
2909 }
2910 }
2911
2912 iter->ent_size = next_size;
2913
2914 if (ent_cpu)
2915 *ent_cpu = next_cpu;
2916
2917 if (ent_ts)
2918 *ent_ts = next_ts;
2919
2920 if (missing_events)
2921 *missing_events = next_lost;
2922
2923 return next;
2924}
2925
2926/* Find the next real entry, without updating the iterator itself */
2927struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
2928 int *ent_cpu, u64 *ent_ts)
2929{
2930 return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
2931}
2932
2933/* Find the next real entry, and increment the iterator to the next entry */
2934void *trace_find_next_entry_inc(struct trace_iterator *iter)
2935{
2936 iter->ent = __find_next_entry(iter, &iter->cpu,
2937 &iter->lost_events, &iter->ts);
2938
2939 if (iter->ent)
2940 trace_iterator_increment(iter);
2941
2942 return iter->ent ? iter : NULL;
2943}
2944
2945static void trace_consume(struct trace_iterator *iter)
2946{
2947 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts,
2948 &iter->lost_events);
2949}
2950
2951static void *s_next(struct seq_file *m, void *v, loff_t *pos)
2952{
2953 struct trace_iterator *iter = m->private;
2954 int i = (int)*pos;
2955 void *ent;
2956
2957 WARN_ON_ONCE(iter->leftover);
2958
2959 (*pos)++;
2960
2961 /* can't go backwards */
2962 if (iter->idx > i)
2963 return NULL;
2964
2965 if (iter->idx < 0)
2966 ent = trace_find_next_entry_inc(iter);
2967 else
2968 ent = iter;
2969
2970 while (ent && iter->idx < i)
2971 ent = trace_find_next_entry_inc(iter);
2972
2973 iter->pos = *pos;
2974
2975 return ent;
2976}
2977
2978void tracing_iter_reset(struct trace_iterator *iter, int cpu)
2979{
2980 struct ring_buffer_event *event;
2981 struct ring_buffer_iter *buf_iter;
2982 unsigned long entries = 0;
2983 u64 ts;
2984
2985 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0;
2986
2987 buf_iter = trace_buffer_iter(iter, cpu);
2988 if (!buf_iter)
2989 return;
2990
2991 ring_buffer_iter_reset(buf_iter);
2992
2993 /*
2994 * We could have the case with the max latency tracers
2995 * that a reset never took place on a cpu. This is evident
2996 * by the timestamp being before the start of the buffer.
2997 */
2998 while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
2999 if (ts >= iter->trace_buffer->time_start)
3000 break;
3001 entries++;
3002 ring_buffer_read(buf_iter, NULL);
3003 }
3004
3005 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries;
3006}
3007
3008/*
3009 * The current tracer is copied to avoid a global locking
3010 * all around.
3011 */
3012static void *s_start(struct seq_file *m, loff_t *pos)
3013{
3014 struct trace_iterator *iter = m->private;
3015 struct trace_array *tr = iter->tr;
3016 int cpu_file = iter->cpu_file;
3017 void *p = NULL;
3018 loff_t l = 0;
3019 int cpu;
3020
3021 /*
3022 * copy the tracer to avoid using a global lock all around.
3023 * iter->trace is a copy of current_trace, the pointer to the
3024 * name may be used instead of a strcmp(), as iter->trace->name
3025 * will point to the same string as current_trace->name.
3026 */
3027 mutex_lock(&trace_types_lock);
3028 if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
3029 *iter->trace = *tr->current_trace;
3030 mutex_unlock(&trace_types_lock);
3031
3032#ifdef CONFIG_TRACER_MAX_TRACE
3033 if (iter->snapshot && iter->trace->use_max_tr)
3034 return ERR_PTR(-EBUSY);
3035#endif
3036
3037 if (!iter->snapshot)
3038 atomic_inc(&trace_record_cmdline_disabled);
3039
3040 if (*pos != iter->pos) {
3041 iter->ent = NULL;
3042 iter->cpu = 0;
3043 iter->idx = -1;
3044
3045 if (cpu_file == RING_BUFFER_ALL_CPUS) {
3046 for_each_tracing_cpu(cpu)
3047 tracing_iter_reset(iter, cpu);
3048 } else
3049 tracing_iter_reset(iter, cpu_file);
3050
3051 iter->leftover = 0;
3052 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
3053 ;
3054
3055 } else {
3056 /*
3057 * If we overflowed the seq_file before, then we want
3058 * to just reuse the trace_seq buffer again.
3059 */
3060 if (iter->leftover)
3061 p = iter;
3062 else {
3063 l = *pos - 1;
3064 p = s_next(m, p, &l);
3065 }
3066 }
3067
3068 trace_event_read_lock();
3069 trace_access_lock(cpu_file);
3070 return p;
3071}
3072
3073static void s_stop(struct seq_file *m, void *p)
3074{
3075 struct trace_iterator *iter = m->private;
3076
3077#ifdef CONFIG_TRACER_MAX_TRACE
3078 if (iter->snapshot && iter->trace->use_max_tr)
3079 return;
3080#endif
3081
3082 if (!iter->snapshot)
3083 atomic_dec(&trace_record_cmdline_disabled);
3084
3085 trace_access_unlock(iter->cpu_file);
3086 trace_event_read_unlock();
3087}
3088
3089static void
3090get_total_entries(struct trace_buffer *buf,
3091 unsigned long *total, unsigned long *entries)
3092{
3093 unsigned long count;
3094 int cpu;
3095
3096 *total = 0;
3097 *entries = 0;
3098
3099 for_each_tracing_cpu(cpu) {
3100 count = ring_buffer_entries_cpu(buf->buffer, cpu);
3101 /*
3102 * If this buffer has skipped entries, then we hold all
3103 * entries for the trace and we need to ignore the
3104 * ones before the time stamp.
3105 */
3106 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
3107 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
3108 /* total is the same as the entries */
3109 *total += count;
3110 } else
3111 *total += count +
3112 ring_buffer_overrun_cpu(buf->buffer, cpu);
3113 *entries += count;
3114 }
3115}
3116
3117static void print_lat_help_header(struct seq_file *m)
3118{
3119 seq_puts(m, "# _------=> CPU# \n"
3120 "# / _-----=> irqs-off \n"
3121 "# | / _----=> need-resched \n"
3122 "# || / _---=> hardirq/softirq \n"
3123 "# ||| / _--=> preempt-depth \n"
3124 "# |||| / delay \n"
3125 "# cmd pid ||||| time | caller \n"
3126 "# \\ / ||||| \\ | / \n");
3127}
3128
3129static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
3130{
3131 unsigned long total;
3132 unsigned long entries;
3133
3134 get_total_entries(buf, &total, &entries);
3135 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
3136 entries, total, num_online_cpus());
3137 seq_puts(m, "#\n");
3138}
3139
3140static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m)
3141{
3142 print_event_info(buf, m);
3143 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n"
3144 "# | | | | |\n");
3145}
3146
3147static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m)
3148{
3149 print_event_info(buf, m);
3150 seq_puts(m, "# _-----=> irqs-off\n"
3151 "# / _----=> need-resched\n"
3152 "# | / _---=> hardirq/softirq\n"
3153 "# || / _--=> preempt-depth\n"
3154 "# ||| / delay\n"
3155 "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n"
3156 "# | | | |||| | |\n");
3157}
3158
3159void
3160print_trace_header(struct seq_file *m, struct trace_iterator *iter)
3161{
3162 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
3163 struct trace_buffer *buf = iter->trace_buffer;
3164 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
3165 struct tracer *type = iter->trace;
3166 unsigned long entries;
3167 unsigned long total;
3168 const char *name = "preemption";
3169
3170 name = type->name;
3171
3172 get_total_entries(buf, &total, &entries);
3173
3174 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
3175 name, UTS_RELEASE);
3176 seq_puts(m, "# -----------------------------------"
3177 "---------------------------------\n");
3178 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
3179 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
3180 nsecs_to_usecs(data->saved_latency),
3181 entries,
3182 total,
3183 buf->cpu,
3184#if defined(CONFIG_PREEMPT_NONE)
3185 "server",
3186#elif defined(CONFIG_PREEMPT_VOLUNTARY)
3187 "desktop",
3188#elif defined(CONFIG_PREEMPT)
3189 "preempt",
3190#else
3191 "unknown",
3192#endif
3193 /* These are reserved for later use */
3194 0, 0, 0, 0);
3195#ifdef CONFIG_SMP
3196 seq_printf(m, " #P:%d)\n", num_online_cpus());
3197#else
3198 seq_puts(m, ")\n");
3199#endif
3200 seq_puts(m, "# -----------------\n");
3201 seq_printf(m, "# | task: %.16s-%d "
3202 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
3203 data->comm, data->pid,
3204 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
3205 data->policy, data->rt_priority);
3206 seq_puts(m, "# -----------------\n");
3207
3208 if (data->critical_start) {
3209 seq_puts(m, "# => started at: ");
3210 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
3211 trace_print_seq(m, &iter->seq);
3212 seq_puts(m, "\n# => ended at: ");
3213 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
3214 trace_print_seq(m, &iter->seq);
3215 seq_puts(m, "\n#\n");
3216 }
3217
3218 seq_puts(m, "#\n");
3219}
3220
3221static void test_cpu_buff_start(struct trace_iterator *iter)
3222{
3223 struct trace_seq *s = &iter->seq;
3224 struct trace_array *tr = iter->tr;
3225
3226 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
3227 return;
3228
3229 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
3230 return;
3231
3232 if (iter->started && cpumask_test_cpu(iter->cpu, iter->started))
3233 return;
3234
3235 if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries)
3236 return;
3237
3238 if (iter->started)
3239 cpumask_set_cpu(iter->cpu, iter->started);
3240
3241 /* Don't print started cpu buffer for the first entry of the trace */
3242 if (iter->idx > 1)
3243 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
3244 iter->cpu);
3245}
3246
3247static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
3248{
3249 struct trace_array *tr = iter->tr;
3250 struct trace_seq *s = &iter->seq;
3251 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
3252 struct trace_entry *entry;
3253 struct trace_event *event;
3254
3255 entry = iter->ent;
3256
3257 test_cpu_buff_start(iter);
3258
3259 event = ftrace_find_event(entry->type);
3260
3261 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3262 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
3263 trace_print_lat_context(iter);
3264 else
3265 trace_print_context(iter);
3266 }
3267
3268 if (trace_seq_has_overflowed(s))
3269 return TRACE_TYPE_PARTIAL_LINE;
3270
3271 if (event)
3272 return event->funcs->trace(iter, sym_flags, event);
3273
3274 trace_seq_printf(s, "Unknown type %d\n", entry->type);
3275
3276 return trace_handle_return(s);
3277}
3278
3279static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
3280{
3281 struct trace_array *tr = iter->tr;
3282 struct trace_seq *s = &iter->seq;
3283 struct trace_entry *entry;
3284 struct trace_event *event;
3285
3286 entry = iter->ent;
3287
3288 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
3289 trace_seq_printf(s, "%d %d %llu ",
3290 entry->pid, iter->cpu, iter->ts);
3291
3292 if (trace_seq_has_overflowed(s))
3293 return TRACE_TYPE_PARTIAL_LINE;
3294
3295 event = ftrace_find_event(entry->type);
3296 if (event)
3297 return event->funcs->raw(iter, 0, event);
3298
3299 trace_seq_printf(s, "%d ?\n", entry->type);
3300
3301 return trace_handle_return(s);
3302}
3303
3304static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
3305{
3306 struct trace_array *tr = iter->tr;
3307 struct trace_seq *s = &iter->seq;
3308 unsigned char newline = '\n';
3309 struct trace_entry *entry;
3310 struct trace_event *event;
3311
3312 entry = iter->ent;
3313
3314 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3315 SEQ_PUT_HEX_FIELD(s, entry->pid);
3316 SEQ_PUT_HEX_FIELD(s, iter->cpu);
3317 SEQ_PUT_HEX_FIELD(s, iter->ts);
3318 if (trace_seq_has_overflowed(s))
3319 return TRACE_TYPE_PARTIAL_LINE;
3320 }
3321
3322 event = ftrace_find_event(entry->type);
3323 if (event) {
3324 enum print_line_t ret = event->funcs->hex(iter, 0, event);
3325 if (ret != TRACE_TYPE_HANDLED)
3326 return ret;
3327 }
3328
3329 SEQ_PUT_FIELD(s, newline);
3330
3331 return trace_handle_return(s);
3332}
3333
3334static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
3335{
3336 struct trace_array *tr = iter->tr;
3337 struct trace_seq *s = &iter->seq;
3338 struct trace_entry *entry;
3339 struct trace_event *event;
3340
3341 entry = iter->ent;
3342
3343 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3344 SEQ_PUT_FIELD(s, entry->pid);
3345 SEQ_PUT_FIELD(s, iter->cpu);
3346 SEQ_PUT_FIELD(s, iter->ts);
3347 if (trace_seq_has_overflowed(s))
3348 return TRACE_TYPE_PARTIAL_LINE;
3349 }
3350
3351 event = ftrace_find_event(entry->type);
3352 return event ? event->funcs->binary(iter, 0, event) :
3353 TRACE_TYPE_HANDLED;
3354}
3355
3356int trace_empty(struct trace_iterator *iter)
3357{
3358 struct ring_buffer_iter *buf_iter;
3359 int cpu;
3360
3361 /* If we are looking at one CPU buffer, only check that one */
3362 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
3363 cpu = iter->cpu_file;
3364 buf_iter = trace_buffer_iter(iter, cpu);
3365 if (buf_iter) {
3366 if (!ring_buffer_iter_empty(buf_iter))
3367 return 0;
3368 } else {
3369 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
3370 return 0;
3371 }
3372 return 1;
3373 }
3374
3375 for_each_tracing_cpu(cpu) {
3376 buf_iter = trace_buffer_iter(iter, cpu);
3377 if (buf_iter) {
3378 if (!ring_buffer_iter_empty(buf_iter))
3379 return 0;
3380 } else {
3381 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
3382 return 0;
3383 }
3384 }
3385
3386 return 1;
3387}
3388
3389/* Called with trace_event_read_lock() held. */
3390enum print_line_t print_trace_line(struct trace_iterator *iter)
3391{
3392 struct trace_array *tr = iter->tr;
3393 unsigned long trace_flags = tr->trace_flags;
3394 enum print_line_t ret;
3395
3396 if (iter->lost_events) {
3397 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
3398 iter->cpu, iter->lost_events);
3399 if (trace_seq_has_overflowed(&iter->seq))
3400 return TRACE_TYPE_PARTIAL_LINE;
3401 }
3402
3403 if (iter->trace && iter->trace->print_line) {
3404 ret = iter->trace->print_line(iter);
3405 if (ret != TRACE_TYPE_UNHANDLED)
3406 return ret;
3407 }
3408
3409 if (iter->ent->type == TRACE_BPUTS &&
3410 trace_flags & TRACE_ITER_PRINTK &&
3411 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3412 return trace_print_bputs_msg_only(iter);
3413
3414 if (iter->ent->type == TRACE_BPRINT &&
3415 trace_flags & TRACE_ITER_PRINTK &&
3416 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3417 return trace_print_bprintk_msg_only(iter);
3418
3419 if (iter->ent->type == TRACE_PRINT &&
3420 trace_flags & TRACE_ITER_PRINTK &&
3421 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3422 return trace_print_printk_msg_only(iter);
3423
3424 if (trace_flags & TRACE_ITER_BIN)
3425 return print_bin_fmt(iter);
3426
3427 if (trace_flags & TRACE_ITER_HEX)
3428 return print_hex_fmt(iter);
3429
3430 if (trace_flags & TRACE_ITER_RAW)
3431 return print_raw_fmt(iter);
3432
3433 return print_trace_fmt(iter);
3434}
3435
3436void trace_latency_header(struct seq_file *m)
3437{
3438 struct trace_iterator *iter = m->private;
3439 struct trace_array *tr = iter->tr;
3440
3441 /* print nothing if the buffers are empty */
3442 if (trace_empty(iter))
3443 return;
3444
3445 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
3446 print_trace_header(m, iter);
3447
3448 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
3449 print_lat_help_header(m);
3450}
3451
3452void trace_default_header(struct seq_file *m)
3453{
3454 struct trace_iterator *iter = m->private;
3455 struct trace_array *tr = iter->tr;
3456 unsigned long trace_flags = tr->trace_flags;
3457
3458 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
3459 return;
3460
3461 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
3462 /* print nothing if the buffers are empty */
3463 if (trace_empty(iter))
3464 return;
3465 print_trace_header(m, iter);
3466 if (!(trace_flags & TRACE_ITER_VERBOSE))
3467 print_lat_help_header(m);
3468 } else {
3469 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
3470 if (trace_flags & TRACE_ITER_IRQ_INFO)
3471 print_func_help_header_irq(iter->trace_buffer, m);
3472 else
3473 print_func_help_header(iter->trace_buffer, m);
3474 }
3475 }
3476}
3477
3478static void test_ftrace_alive(struct seq_file *m)
3479{
3480 if (!ftrace_is_dead())
3481 return;
3482 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
3483 "# MAY BE MISSING FUNCTION EVENTS\n");
3484}
3485
3486#ifdef CONFIG_TRACER_MAX_TRACE
3487static void show_snapshot_main_help(struct seq_file *m)
3488{
3489 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
3490 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
3491 "# Takes a snapshot of the main buffer.\n"
3492 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
3493 "# (Doesn't have to be '2' works with any number that\n"
3494 "# is not a '0' or '1')\n");
3495}
3496
3497static void show_snapshot_percpu_help(struct seq_file *m)
3498{
3499 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
3500#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
3501 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
3502 "# Takes a snapshot of the main buffer for this cpu.\n");
3503#else
3504 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
3505 "# Must use main snapshot file to allocate.\n");
3506#endif
3507 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
3508 "# (Doesn't have to be '2' works with any number that\n"
3509 "# is not a '0' or '1')\n");
3510}
3511
3512static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
3513{
3514 if (iter->tr->allocated_snapshot)
3515 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
3516 else
3517 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
3518
3519 seq_puts(m, "# Snapshot commands:\n");
3520 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
3521 show_snapshot_main_help(m);
3522 else
3523 show_snapshot_percpu_help(m);
3524}
3525#else
3526/* Should never be called */
3527static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
3528#endif
3529
3530static int s_show(struct seq_file *m, void *v)
3531{
3532 struct trace_iterator *iter = v;
3533 int ret;
3534
3535 if (iter->ent == NULL) {
3536 if (iter->tr) {
3537 seq_printf(m, "# tracer: %s\n", iter->trace->name);
3538 seq_puts(m, "#\n");
3539 test_ftrace_alive(m);
3540 }
3541 if (iter->snapshot && trace_empty(iter))
3542 print_snapshot_help(m, iter);
3543 else if (iter->trace && iter->trace->print_header)
3544 iter->trace->print_header(m);
3545 else
3546 trace_default_header(m);
3547
3548 } else if (iter->leftover) {
3549 /*
3550 * If we filled the seq_file buffer earlier, we
3551 * want to just show it now.
3552 */
3553 ret = trace_print_seq(m, &iter->seq);
3554
3555 /* ret should this time be zero, but you never know */
3556 iter->leftover = ret;
3557
3558 } else {
3559 print_trace_line(iter);
3560 ret = trace_print_seq(m, &iter->seq);
3561 /*
3562 * If we overflow the seq_file buffer, then it will
3563 * ask us for this data again at start up.
3564 * Use that instead.
3565 * ret is 0 if seq_file write succeeded.
3566 * -1 otherwise.
3567 */
3568 iter->leftover = ret;
3569 }
3570
3571 return 0;
3572}
3573
3574/*
3575 * Should be used after trace_array_get(), trace_types_lock
3576 * ensures that i_cdev was already initialized.
3577 */
3578static inline int tracing_get_cpu(struct inode *inode)
3579{
3580 if (inode->i_cdev) /* See trace_create_cpu_file() */
3581 return (long)inode->i_cdev - 1;
3582 return RING_BUFFER_ALL_CPUS;
3583}
3584
3585static const struct seq_operations tracer_seq_ops = {
3586 .start = s_start,
3587 .next = s_next,
3588 .stop = s_stop,
3589 .show = s_show,
3590};
3591
3592static struct trace_iterator *
3593__tracing_open(struct inode *inode, struct file *file, bool snapshot)
3594{
3595 struct trace_array *tr = inode->i_private;
3596 struct trace_iterator *iter;
3597 int cpu;
3598
3599 if (tracing_disabled)
3600 return ERR_PTR(-ENODEV);
3601
3602 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
3603 if (!iter)
3604 return ERR_PTR(-ENOMEM);
3605
3606 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
3607 GFP_KERNEL);
3608 if (!iter->buffer_iter)
3609 goto release;
3610
3611 /*
3612 * We make a copy of the current tracer to avoid concurrent
3613 * changes on it while we are reading.
3614 */
3615 mutex_lock(&trace_types_lock);
3616 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
3617 if (!iter->trace)
3618 goto fail;
3619
3620 *iter->trace = *tr->current_trace;
3621
3622 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
3623 goto fail;
3624
3625 iter->tr = tr;
3626
3627#ifdef CONFIG_TRACER_MAX_TRACE
3628 /* Currently only the top directory has a snapshot */
3629 if (tr->current_trace->print_max || snapshot)
3630 iter->trace_buffer = &tr->max_buffer;
3631 else
3632#endif
3633 iter->trace_buffer = &tr->trace_buffer;
3634 iter->snapshot = snapshot;
3635 iter->pos = -1;
3636 iter->cpu_file = tracing_get_cpu(inode);
3637 mutex_init(&iter->mutex);
3638
3639 /* Notify the tracer early; before we stop tracing. */
3640 if (iter->trace && iter->trace->open)
3641 iter->trace->open(iter);
3642
3643 /* Annotate start of buffers if we had overruns */
3644 if (ring_buffer_overruns(iter->trace_buffer->buffer))
3645 iter->iter_flags |= TRACE_FILE_ANNOTATE;
3646
3647 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
3648 if (trace_clocks[tr->clock_id].in_ns)
3649 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
3650
3651 /* stop the trace while dumping if we are not opening "snapshot" */
3652 if (!iter->snapshot)
3653 tracing_stop_tr(tr);
3654
3655 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
3656 for_each_tracing_cpu(cpu) {
3657 iter->buffer_iter[cpu] =
3658 ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
3659 }
3660 ring_buffer_read_prepare_sync();
3661 for_each_tracing_cpu(cpu) {
3662 ring_buffer_read_start(iter->buffer_iter[cpu]);
3663 tracing_iter_reset(iter, cpu);
3664 }
3665 } else {
3666 cpu = iter->cpu_file;
3667 iter->buffer_iter[cpu] =
3668 ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
3669 ring_buffer_read_prepare_sync();
3670 ring_buffer_read_start(iter->buffer_iter[cpu]);
3671 tracing_iter_reset(iter, cpu);
3672 }
3673
3674 mutex_unlock(&trace_types_lock);
3675
3676 return iter;
3677
3678 fail:
3679 mutex_unlock(&trace_types_lock);
3680 kfree(iter->trace);
3681 kfree(iter->buffer_iter);
3682release:
3683 seq_release_private(inode, file);
3684 return ERR_PTR(-ENOMEM);
3685}
3686
3687int tracing_open_generic(struct inode *inode, struct file *filp)
3688{
3689 if (tracing_disabled)
3690 return -ENODEV;
3691
3692 filp->private_data = inode->i_private;
3693 return 0;
3694}
3695
3696bool tracing_is_disabled(void)
3697{
3698 return (tracing_disabled) ? true: false;
3699}
3700
3701/*
3702 * Open and update trace_array ref count.
3703 * Must have the current trace_array passed to it.
3704 */
3705static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
3706{
3707 struct trace_array *tr = inode->i_private;
3708
3709 if (tracing_disabled)
3710 return -ENODEV;
3711
3712 if (trace_array_get(tr) < 0)
3713 return -ENODEV;
3714
3715 filp->private_data = inode->i_private;
3716
3717 return 0;
3718}
3719
3720static int tracing_release(struct inode *inode, struct file *file)
3721{
3722 struct trace_array *tr = inode->i_private;
3723 struct seq_file *m = file->private_data;
3724 struct trace_iterator *iter;
3725 int cpu;
3726
3727 if (!(file->f_mode & FMODE_READ)) {
3728 trace_array_put(tr);
3729 return 0;
3730 }
3731
3732 /* Writes do not use seq_file */
3733 iter = m->private;
3734 mutex_lock(&trace_types_lock);
3735
3736 for_each_tracing_cpu(cpu) {
3737 if (iter->buffer_iter[cpu])
3738 ring_buffer_read_finish(iter->buffer_iter[cpu]);
3739 }
3740
3741 if (iter->trace && iter->trace->close)
3742 iter->trace->close(iter);
3743
3744 if (!iter->snapshot)
3745 /* reenable tracing if it was previously enabled */
3746 tracing_start_tr(tr);
3747
3748 __trace_array_put(tr);
3749
3750 mutex_unlock(&trace_types_lock);
3751
3752 mutex_destroy(&iter->mutex);
3753 free_cpumask_var(iter->started);
3754 kfree(iter->trace);
3755 kfree(iter->buffer_iter);
3756 seq_release_private(inode, file);
3757
3758 return 0;
3759}
3760
3761static int tracing_release_generic_tr(struct inode *inode, struct file *file)
3762{
3763 struct trace_array *tr = inode->i_private;
3764
3765 trace_array_put(tr);
3766 return 0;
3767}
3768
3769static int tracing_single_release_tr(struct inode *inode, struct file *file)
3770{
3771 struct trace_array *tr = inode->i_private;
3772
3773 trace_array_put(tr);
3774
3775 return single_release(inode, file);
3776}
3777
3778static int tracing_open(struct inode *inode, struct file *file)
3779{
3780 struct trace_array *tr = inode->i_private;
3781 struct trace_iterator *iter;
3782 int ret = 0;
3783
3784 if (trace_array_get(tr) < 0)
3785 return -ENODEV;
3786
3787 /* If this file was open for write, then erase contents */
3788 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
3789 int cpu = tracing_get_cpu(inode);
3790
3791 if (cpu == RING_BUFFER_ALL_CPUS)
3792 tracing_reset_online_cpus(&tr->trace_buffer);
3793 else
3794 tracing_reset(&tr->trace_buffer, cpu);
3795 }
3796
3797 if (file->f_mode & FMODE_READ) {
3798 iter = __tracing_open(inode, file, false);
3799 if (IS_ERR(iter))
3800 ret = PTR_ERR(iter);
3801 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
3802 iter->iter_flags |= TRACE_FILE_LAT_FMT;
3803 }
3804
3805 if (ret < 0)
3806 trace_array_put(tr);
3807
3808 return ret;
3809}
3810
3811/*
3812 * Some tracers are not suitable for instance buffers.
3813 * A tracer is always available for the global array (toplevel)
3814 * or if it explicitly states that it is.
3815 */
3816static bool
3817trace_ok_for_array(struct tracer *t, struct trace_array *tr)
3818{
3819 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
3820}
3821
3822/* Find the next tracer that this trace array may use */
3823static struct tracer *
3824get_tracer_for_array(struct trace_array *tr, struct tracer *t)
3825{
3826 while (t && !trace_ok_for_array(t, tr))
3827 t = t->next;
3828
3829 return t;
3830}
3831
3832static void *
3833t_next(struct seq_file *m, void *v, loff_t *pos)
3834{
3835 struct trace_array *tr = m->private;
3836 struct tracer *t = v;
3837
3838 (*pos)++;
3839
3840 if (t)
3841 t = get_tracer_for_array(tr, t->next);
3842
3843 return t;
3844}
3845
3846static void *t_start(struct seq_file *m, loff_t *pos)
3847{
3848 struct trace_array *tr = m->private;
3849 struct tracer *t;
3850 loff_t l = 0;
3851
3852 mutex_lock(&trace_types_lock);
3853
3854 t = get_tracer_for_array(tr, trace_types);
3855 for (; t && l < *pos; t = t_next(m, t, &l))
3856 ;
3857
3858 return t;
3859}
3860
3861static void t_stop(struct seq_file *m, void *p)
3862{
3863 mutex_unlock(&trace_types_lock);
3864}
3865
3866static int t_show(struct seq_file *m, void *v)
3867{
3868 struct tracer *t = v;
3869
3870 if (!t)
3871 return 0;
3872
3873 seq_puts(m, t->name);
3874 if (t->next)
3875 seq_putc(m, ' ');
3876 else
3877 seq_putc(m, '\n');
3878
3879 return 0;
3880}
3881
3882static const struct seq_operations show_traces_seq_ops = {
3883 .start = t_start,
3884 .next = t_next,
3885 .stop = t_stop,
3886 .show = t_show,
3887};
3888
3889static int show_traces_open(struct inode *inode, struct file *file)
3890{
3891 struct trace_array *tr = inode->i_private;
3892 struct seq_file *m;
3893 int ret;
3894
3895 if (tracing_disabled)
3896 return -ENODEV;
3897
3898 ret = seq_open(file, &show_traces_seq_ops);
3899 if (ret)
3900 return ret;
3901
3902 m = file->private_data;
3903 m->private = tr;
3904
3905 return 0;
3906}
3907
3908static ssize_t
3909tracing_write_stub(struct file *filp, const char __user *ubuf,
3910 size_t count, loff_t *ppos)
3911{
3912 return count;
3913}
3914
3915loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
3916{
3917 int ret;
3918
3919 if (file->f_mode & FMODE_READ)
3920 ret = seq_lseek(file, offset, whence);
3921 else
3922 file->f_pos = ret = 0;
3923
3924 return ret;
3925}
3926
3927static const struct file_operations tracing_fops = {
3928 .open = tracing_open,
3929 .read = seq_read,
3930 .write = tracing_write_stub,
3931 .llseek = tracing_lseek,
3932 .release = tracing_release,
3933};
3934
3935static const struct file_operations show_traces_fops = {
3936 .open = show_traces_open,
3937 .read = seq_read,
3938 .release = seq_release,
3939 .llseek = seq_lseek,
3940};
3941
3942/*
3943 * The tracer itself will not take this lock, but still we want
3944 * to provide a consistent cpumask to user-space:
3945 */
3946static DEFINE_MUTEX(tracing_cpumask_update_lock);
3947
3948/*
3949 * Temporary storage for the character representation of the
3950 * CPU bitmask (and one more byte for the newline):
3951 */
3952static char mask_str[NR_CPUS + 1];
3953
3954static ssize_t
3955tracing_cpumask_read(struct file *filp, char __user *ubuf,
3956 size_t count, loff_t *ppos)
3957{
3958 struct trace_array *tr = file_inode(filp)->i_private;
3959 int len;
3960
3961 mutex_lock(&tracing_cpumask_update_lock);
3962
3963 len = snprintf(mask_str, count, "%*pb\n",
3964 cpumask_pr_args(tr->tracing_cpumask));
3965 if (len >= count) {
3966 count = -EINVAL;
3967 goto out_err;
3968 }
3969 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
3970
3971out_err:
3972 mutex_unlock(&tracing_cpumask_update_lock);
3973
3974 return count;
3975}
3976
3977static ssize_t
3978tracing_cpumask_write(struct file *filp, const char __user *ubuf,
3979 size_t count, loff_t *ppos)
3980{
3981 struct trace_array *tr = file_inode(filp)->i_private;
3982 cpumask_var_t tracing_cpumask_new;
3983 int err, cpu;
3984
3985 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
3986 return -ENOMEM;
3987
3988 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
3989 if (err)
3990 goto err_unlock;
3991
3992 mutex_lock(&tracing_cpumask_update_lock);
3993
3994 local_irq_disable();
3995 arch_spin_lock(&tr->max_lock);
3996 for_each_tracing_cpu(cpu) {
3997 /*
3998 * Increase/decrease the disabled counter if we are
3999 * about to flip a bit in the cpumask:
4000 */
4001 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
4002 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
4003 atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
4004 ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);
4005 }
4006 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
4007 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
4008 atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
4009 ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
4010 }
4011 }
4012 arch_spin_unlock(&tr->max_lock);
4013 local_irq_enable();
4014
4015 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
4016
4017 mutex_unlock(&tracing_cpumask_update_lock);
4018 free_cpumask_var(tracing_cpumask_new);
4019
4020 return count;
4021
4022err_unlock:
4023 free_cpumask_var(tracing_cpumask_new);
4024
4025 return err;
4026}
4027
4028static const struct file_operations tracing_cpumask_fops = {
4029 .open = tracing_open_generic_tr,
4030 .read = tracing_cpumask_read,
4031 .write = tracing_cpumask_write,
4032 .release = tracing_release_generic_tr,
4033 .llseek = generic_file_llseek,
4034};
4035
4036static int tracing_trace_options_show(struct seq_file *m, void *v)
4037{
4038 struct tracer_opt *trace_opts;
4039 struct trace_array *tr = m->private;
4040 u32 tracer_flags;
4041 int i;
4042
4043 mutex_lock(&trace_types_lock);
4044 tracer_flags = tr->current_trace->flags->val;
4045 trace_opts = tr->current_trace->flags->opts;
4046
4047 for (i = 0; trace_options[i]; i++) {
4048 if (tr->trace_flags & (1 << i))
4049 seq_printf(m, "%s\n", trace_options[i]);
4050 else
4051 seq_printf(m, "no%s\n", trace_options[i]);
4052 }
4053
4054 for (i = 0; trace_opts[i].name; i++) {
4055 if (tracer_flags & trace_opts[i].bit)
4056 seq_printf(m, "%s\n", trace_opts[i].name);
4057 else
4058 seq_printf(m, "no%s\n", trace_opts[i].name);
4059 }
4060 mutex_unlock(&trace_types_lock);
4061
4062 return 0;
4063}
4064
4065static int __set_tracer_option(struct trace_array *tr,
4066 struct tracer_flags *tracer_flags,
4067 struct tracer_opt *opts, int neg)
4068{
4069 struct tracer *trace = tracer_flags->trace;
4070 int ret;
4071
4072 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
4073 if (ret)
4074 return ret;
4075
4076 if (neg)
4077 tracer_flags->val &= ~opts->bit;
4078 else
4079 tracer_flags->val |= opts->bit;
4080 return 0;
4081}
4082
4083/* Try to assign a tracer specific option */
4084static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
4085{
4086 struct tracer *trace = tr->current_trace;
4087 struct tracer_flags *tracer_flags = trace->flags;
4088 struct tracer_opt *opts = NULL;
4089 int i;
4090
4091 for (i = 0; tracer_flags->opts[i].name; i++) {
4092 opts = &tracer_flags->opts[i];
4093
4094 if (strcmp(cmp, opts->name) == 0)
4095 return __set_tracer_option(tr, trace->flags, opts, neg);
4096 }
4097
4098 return -EINVAL;
4099}
4100
4101/* Some tracers require overwrite to stay enabled */
4102int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
4103{
4104 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
4105 return -1;
4106
4107 return 0;
4108}
4109
4110int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
4111{
4112 /* do nothing if flag is already set */
4113 if (!!(tr->trace_flags & mask) == !!enabled)
4114 return 0;
4115
4116 /* Give the tracer a chance to approve the change */
4117 if (tr->current_trace->flag_changed)
4118 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
4119 return -EINVAL;
4120
4121 if (enabled)
4122 tr->trace_flags |= mask;
4123 else
4124 tr->trace_flags &= ~mask;
4125
4126 if (mask == TRACE_ITER_RECORD_CMD)
4127 trace_event_enable_cmd_record(enabled);
4128
4129 if (mask == TRACE_ITER_EVENT_FORK)
4130 trace_event_follow_fork(tr, enabled);
4131
4132 if (mask == TRACE_ITER_OVERWRITE) {
4133 ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled);
4134#ifdef CONFIG_TRACER_MAX_TRACE
4135 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
4136#endif
4137 }
4138
4139 if (mask == TRACE_ITER_PRINTK) {
4140 trace_printk_start_stop_comm(enabled);
4141 trace_printk_control(enabled);
4142 }
4143
4144 return 0;
4145}
4146
4147static int trace_set_options(struct trace_array *tr, char *option)
4148{
4149 char *cmp;
4150 int neg = 0;
4151 int ret = -ENODEV;
4152 int i;
4153 size_t orig_len = strlen(option);
4154
4155 cmp = strstrip(option);
4156
4157 if (strncmp(cmp, "no", 2) == 0) {
4158 neg = 1;
4159 cmp += 2;
4160 }
4161
4162 mutex_lock(&trace_types_lock);
4163
4164 for (i = 0; trace_options[i]; i++) {
4165 if (strcmp(cmp, trace_options[i]) == 0) {
4166 ret = set_tracer_flag(tr, 1 << i, !neg);
4167 break;
4168 }
4169 }
4170
4171 /* If no option could be set, test the specific tracer options */
4172 if (!trace_options[i])
4173 ret = set_tracer_option(tr, cmp, neg);
4174
4175 mutex_unlock(&trace_types_lock);
4176
4177 /*
4178 * If the first trailing whitespace is replaced with '\0' by strstrip,
4179 * turn it back into a space.
4180 */
4181 if (orig_len > strlen(option))
4182 option[strlen(option)] = ' ';
4183
4184 return ret;
4185}
4186
4187static void __init apply_trace_boot_options(void)
4188{
4189 char *buf = trace_boot_options_buf;
4190 char *option;
4191
4192 while (true) {
4193 option = strsep(&buf, ",");
4194
4195 if (!option)
4196 break;
4197
4198 if (*option)
4199 trace_set_options(&global_trace, option);
4200
4201 /* Put back the comma to allow this to be called again */
4202 if (buf)
4203 *(buf - 1) = ',';
4204 }
4205}
4206
4207static ssize_t
4208tracing_trace_options_write(struct file *filp, const char __user *ubuf,
4209 size_t cnt, loff_t *ppos)
4210{
4211 struct seq_file *m = filp->private_data;
4212 struct trace_array *tr = m->private;
4213 char buf[64];
4214 int ret;
4215
4216 if (cnt >= sizeof(buf))
4217 return -EINVAL;
4218
4219 if (copy_from_user(buf, ubuf, cnt))
4220 return -EFAULT;
4221
4222 buf[cnt] = 0;
4223
4224 ret = trace_set_options(tr, buf);
4225 if (ret < 0)
4226 return ret;
4227
4228 *ppos += cnt;
4229
4230 return cnt;
4231}
4232
4233static int tracing_trace_options_open(struct inode *inode, struct file *file)
4234{
4235 struct trace_array *tr = inode->i_private;
4236 int ret;
4237
4238 if (tracing_disabled)
4239 return -ENODEV;
4240
4241 if (trace_array_get(tr) < 0)
4242 return -ENODEV;
4243
4244 ret = single_open(file, tracing_trace_options_show, inode->i_private);
4245 if (ret < 0)
4246 trace_array_put(tr);
4247
4248 return ret;
4249}
4250
4251static const struct file_operations tracing_iter_fops = {
4252 .open = tracing_trace_options_open,
4253 .read = seq_read,
4254 .llseek = seq_lseek,
4255 .release = tracing_single_release_tr,
4256 .write = tracing_trace_options_write,
4257};
4258
4259static const char readme_msg[] =
4260 "tracing mini-HOWTO:\n\n"
4261 "# echo 0 > tracing_on : quick way to disable tracing\n"
4262 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
4263 " Important files:\n"
4264 " trace\t\t\t- The static contents of the buffer\n"
4265 "\t\t\t To clear the buffer write into this file: echo > trace\n"
4266 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
4267 " current_tracer\t- function and latency tracers\n"
4268 " available_tracers\t- list of configured tracers for current_tracer\n"
4269 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
4270 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
4271 " trace_clock\t\t-change the clock used to order events\n"
4272 " local: Per cpu clock but may not be synced across CPUs\n"
4273 " global: Synced across CPUs but slows tracing down.\n"
4274 " counter: Not a clock, but just an increment\n"
4275 " uptime: Jiffy counter from time of boot\n"
4276 " perf: Same clock that perf events use\n"
4277#ifdef CONFIG_X86_64
4278 " x86-tsc: TSC cycle counter\n"
4279#endif
4280 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
4281 "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
4282 " tracing_cpumask\t- Limit which CPUs to trace\n"
4283 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
4284 "\t\t\t Remove sub-buffer with rmdir\n"
4285 " trace_options\t\t- Set format or modify how tracing happens\n"
4286 "\t\t\t Disable an option by adding a suffix 'no' to the\n"
4287 "\t\t\t option name\n"
4288 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
4289#ifdef CONFIG_DYNAMIC_FTRACE
4290 "\n available_filter_functions - list of functions that can be filtered on\n"
4291 " set_ftrace_filter\t- echo function name in here to only trace these\n"
4292 "\t\t\t functions\n"
4293 "\t accepts: func_full_name or glob-matching-pattern\n"
4294 "\t modules: Can select a group via module\n"
4295 "\t Format: :mod:<module-name>\n"
4296 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
4297 "\t triggers: a command to perform when function is hit\n"
4298 "\t Format: <function>:<trigger>[:count]\n"
4299 "\t trigger: traceon, traceoff\n"
4300 "\t\t enable_event:<system>:<event>\n"
4301 "\t\t disable_event:<system>:<event>\n"
4302#ifdef CONFIG_STACKTRACE
4303 "\t\t stacktrace\n"
4304#endif
4305#ifdef CONFIG_TRACER_SNAPSHOT
4306 "\t\t snapshot\n"
4307#endif
4308 "\t\t dump\n"
4309 "\t\t cpudump\n"
4310 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
4311 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
4312 "\t The first one will disable tracing every time do_fault is hit\n"
4313 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
4314 "\t The first time do trap is hit and it disables tracing, the\n"
4315 "\t counter will decrement to 2. If tracing is already disabled,\n"
4316 "\t the counter will not decrement. It only decrements when the\n"
4317 "\t trigger did work\n"
4318 "\t To remove trigger without count:\n"
4319 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
4320 "\t To remove trigger with a count:\n"
4321 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
4322 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
4323 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
4324 "\t modules: Can select a group via module command :mod:\n"
4325 "\t Does not accept triggers\n"
4326#endif /* CONFIG_DYNAMIC_FTRACE */
4327#ifdef CONFIG_FUNCTION_TRACER
4328 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
4329 "\t\t (function)\n"
4330#endif
4331#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4332 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
4333 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
4334 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
4335#endif
4336#ifdef CONFIG_TRACER_SNAPSHOT
4337 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
4338 "\t\t\t snapshot buffer. Read the contents for more\n"
4339 "\t\t\t information\n"
4340#endif
4341#ifdef CONFIG_STACK_TRACER
4342 " stack_trace\t\t- Shows the max stack trace when active\n"
4343 " stack_max_size\t- Shows current max stack size that was traced\n"
4344 "\t\t\t Write into this file to reset the max size (trigger a\n"
4345 "\t\t\t new trace)\n"
4346#ifdef CONFIG_DYNAMIC_FTRACE
4347 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
4348 "\t\t\t traces\n"
4349#endif
4350#endif /* CONFIG_STACK_TRACER */
4351#ifdef CONFIG_KPROBE_EVENT
4352 " kprobe_events\t\t- Add/remove/show the kernel dynamic events\n"
4353 "\t\t\t Write into this file to define/undefine new trace events.\n"
4354#endif
4355#ifdef CONFIG_UPROBE_EVENT
4356 " uprobe_events\t\t- Add/remove/show the userspace dynamic events\n"
4357 "\t\t\t Write into this file to define/undefine new trace events.\n"
4358#endif
4359#if defined(CONFIG_KPROBE_EVENT) || defined(CONFIG_UPROBE_EVENT)
4360 "\t accepts: event-definitions (one definition per line)\n"
4361 "\t Format: p|r[:[<group>/]<event>] <place> [<args>]\n"
4362 "\t -:[<group>/]<event>\n"
4363#ifdef CONFIG_KPROBE_EVENT
4364 "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
4365#endif
4366#ifdef CONFIG_UPROBE_EVENT
4367 "\t place: <path>:<offset>\n"
4368#endif
4369 "\t args: <name>=fetcharg[:type]\n"
4370 "\t fetcharg: %<register>, @<address>, @<symbol>[+|-<offset>],\n"
4371 "\t $stack<index>, $stack, $retval, $comm\n"
4372 "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string,\n"
4373 "\t b<bit-width>@<bit-offset>/<container-size>\n"
4374#endif
4375 " events/\t\t- Directory containing all trace event subsystems:\n"
4376 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
4377 " events/<system>/\t- Directory containing all trace events for <system>:\n"
4378 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
4379 "\t\t\t events\n"
4380 " filter\t\t- If set, only events passing filter are traced\n"
4381 " events/<system>/<event>/\t- Directory containing control files for\n"
4382 "\t\t\t <event>:\n"
4383 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
4384 " filter\t\t- If set, only events passing filter are traced\n"
4385 " trigger\t\t- If set, a command to perform when event is hit\n"
4386 "\t Format: <trigger>[:count][if <filter>]\n"
4387 "\t trigger: traceon, traceoff\n"
4388 "\t enable_event:<system>:<event>\n"
4389 "\t disable_event:<system>:<event>\n"
4390#ifdef CONFIG_HIST_TRIGGERS
4391 "\t enable_hist:<system>:<event>\n"
4392 "\t disable_hist:<system>:<event>\n"
4393#endif
4394#ifdef CONFIG_STACKTRACE
4395 "\t\t stacktrace\n"
4396#endif
4397#ifdef CONFIG_TRACER_SNAPSHOT
4398 "\t\t snapshot\n"
4399#endif
4400#ifdef CONFIG_HIST_TRIGGERS
4401 "\t\t hist (see below)\n"
4402#endif
4403 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
4404 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
4405 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
4406 "\t events/block/block_unplug/trigger\n"
4407 "\t The first disables tracing every time block_unplug is hit.\n"
4408 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
4409 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
4410 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
4411 "\t Like function triggers, the counter is only decremented if it\n"
4412 "\t enabled or disabled tracing.\n"
4413 "\t To remove a trigger without a count:\n"
4414 "\t echo '!<trigger> > <system>/<event>/trigger\n"
4415 "\t To remove a trigger with a count:\n"
4416 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
4417 "\t Filters can be ignored when removing a trigger.\n"
4418#ifdef CONFIG_HIST_TRIGGERS
4419 " hist trigger\t- If set, event hits are aggregated into a hash table\n"
4420 "\t Format: hist:keys=<field1[,field2,...]>\n"
4421 "\t [:values=<field1[,field2,...]>]\n"
4422 "\t [:sort=<field1[,field2,...]>]\n"
4423 "\t [:size=#entries]\n"
4424 "\t [:pause][:continue][:clear]\n"
4425 "\t [:name=histname1]\n"
4426 "\t [if <filter>]\n\n"
4427 "\t When a matching event is hit, an entry is added to a hash\n"
4428 "\t table using the key(s) and value(s) named, and the value of a\n"
4429 "\t sum called 'hitcount' is incremented. Keys and values\n"
4430 "\t correspond to fields in the event's format description. Keys\n"
4431 "\t can be any field, or the special string 'stacktrace'.\n"
4432 "\t Compound keys consisting of up to two fields can be specified\n"
4433 "\t by the 'keys' keyword. Values must correspond to numeric\n"
4434 "\t fields. Sort keys consisting of up to two fields can be\n"
4435 "\t specified using the 'sort' keyword. The sort direction can\n"
4436 "\t be modified by appending '.descending' or '.ascending' to a\n"
4437 "\t sort field. The 'size' parameter can be used to specify more\n"
4438 "\t or fewer than the default 2048 entries for the hashtable size.\n"
4439 "\t If a hist trigger is given a name using the 'name' parameter,\n"
4440 "\t its histogram data will be shared with other triggers of the\n"
4441 "\t same name, and trigger hits will update this common data.\n\n"
4442 "\t Reading the 'hist' file for the event will dump the hash\n"
4443 "\t table in its entirety to stdout. If there are multiple hist\n"
4444 "\t triggers attached to an event, there will be a table for each\n"
4445 "\t trigger in the output. The table displayed for a named\n"
4446 "\t trigger will be the same as any other instance having the\n"
4447 "\t same name. The default format used to display a given field\n"
4448 "\t can be modified by appending any of the following modifiers\n"
4449 "\t to the field name, as applicable:\n\n"
4450 "\t .hex display a number as a hex value\n"
4451 "\t .sym display an address as a symbol\n"
4452 "\t .sym-offset display an address as a symbol and offset\n"
4453 "\t .execname display a common_pid as a program name\n"
4454 "\t .syscall display a syscall id as a syscall name\n\n"
4455 "\t .log2 display log2 value rather than raw number\n\n"
4456 "\t The 'pause' parameter can be used to pause an existing hist\n"
4457 "\t trigger or to start a hist trigger but not log any events\n"
4458 "\t until told to do so. 'continue' can be used to start or\n"
4459 "\t restart a paused hist trigger.\n\n"
4460 "\t The 'clear' parameter will clear the contents of a running\n"
4461 "\t hist trigger and leave its current paused/active state\n"
4462 "\t unchanged.\n\n"
4463 "\t The enable_hist and disable_hist triggers can be used to\n"
4464 "\t have one event conditionally start and stop another event's\n"
4465 "\t already-attached hist trigger. The syntax is analagous to\n"
4466 "\t the enable_event and disable_event triggers.\n"
4467#endif
4468;
4469
4470static ssize_t
4471tracing_readme_read(struct file *filp, char __user *ubuf,
4472 size_t cnt, loff_t *ppos)
4473{
4474 return simple_read_from_buffer(ubuf, cnt, ppos,
4475 readme_msg, strlen(readme_msg));
4476}
4477
4478static const struct file_operations tracing_readme_fops = {
4479 .open = tracing_open_generic,
4480 .read = tracing_readme_read,
4481 .llseek = generic_file_llseek,
4482};
4483
4484static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
4485{
4486 unsigned int *ptr = v;
4487
4488 if (*pos || m->count)
4489 ptr++;
4490
4491 (*pos)++;
4492
4493 for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
4494 ptr++) {
4495 if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
4496 continue;
4497
4498 return ptr;
4499 }
4500
4501 return NULL;
4502}
4503
4504static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
4505{
4506 void *v;
4507 loff_t l = 0;
4508
4509 preempt_disable();
4510 arch_spin_lock(&trace_cmdline_lock);
4511
4512 v = &savedcmd->map_cmdline_to_pid[0];
4513 while (l <= *pos) {
4514 v = saved_cmdlines_next(m, v, &l);
4515 if (!v)
4516 return NULL;
4517 }
4518
4519 return v;
4520}
4521
4522static void saved_cmdlines_stop(struct seq_file *m, void *v)
4523{
4524 arch_spin_unlock(&trace_cmdline_lock);
4525 preempt_enable();
4526}
4527
4528static int saved_cmdlines_show(struct seq_file *m, void *v)
4529{
4530 char buf[TASK_COMM_LEN];
4531 unsigned int *pid = v;
4532
4533 __trace_find_cmdline(*pid, buf);
4534 seq_printf(m, "%d %s\n", *pid, buf);
4535 return 0;
4536}
4537
4538static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
4539 .start = saved_cmdlines_start,
4540 .next = saved_cmdlines_next,
4541 .stop = saved_cmdlines_stop,
4542 .show = saved_cmdlines_show,
4543};
4544
4545static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
4546{
4547 if (tracing_disabled)
4548 return -ENODEV;
4549
4550 return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
4551}
4552
4553static const struct file_operations tracing_saved_cmdlines_fops = {
4554 .open = tracing_saved_cmdlines_open,
4555 .read = seq_read,
4556 .llseek = seq_lseek,
4557 .release = seq_release,
4558};
4559
4560static ssize_t
4561tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
4562 size_t cnt, loff_t *ppos)
4563{
4564 char buf[64];
4565 int r;
4566
4567 arch_spin_lock(&trace_cmdline_lock);
4568 r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
4569 arch_spin_unlock(&trace_cmdline_lock);
4570
4571 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4572}
4573
4574static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
4575{
4576 kfree(s->saved_cmdlines);
4577 kfree(s->map_cmdline_to_pid);
4578 kfree(s);
4579}
4580
4581static int tracing_resize_saved_cmdlines(unsigned int val)
4582{
4583 struct saved_cmdlines_buffer *s, *savedcmd_temp;
4584
4585 s = kmalloc(sizeof(*s), GFP_KERNEL);
4586 if (!s)
4587 return -ENOMEM;
4588
4589 if (allocate_cmdlines_buffer(val, s) < 0) {
4590 kfree(s);
4591 return -ENOMEM;
4592 }
4593
4594 arch_spin_lock(&trace_cmdline_lock);
4595 savedcmd_temp = savedcmd;
4596 savedcmd = s;
4597 arch_spin_unlock(&trace_cmdline_lock);
4598 free_saved_cmdlines_buffer(savedcmd_temp);
4599
4600 return 0;
4601}
4602
4603static ssize_t
4604tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
4605 size_t cnt, loff_t *ppos)
4606{
4607 unsigned long val;
4608 int ret;
4609
4610 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4611 if (ret)
4612 return ret;
4613
4614 /* must have at least 1 entry or less than PID_MAX_DEFAULT */
4615 if (!val || val > PID_MAX_DEFAULT)
4616 return -EINVAL;
4617
4618 ret = tracing_resize_saved_cmdlines((unsigned int)val);
4619 if (ret < 0)
4620 return ret;
4621
4622 *ppos += cnt;
4623
4624 return cnt;
4625}
4626
4627static const struct file_operations tracing_saved_cmdlines_size_fops = {
4628 .open = tracing_open_generic,
4629 .read = tracing_saved_cmdlines_size_read,
4630 .write = tracing_saved_cmdlines_size_write,
4631};
4632
4633#ifdef CONFIG_TRACE_ENUM_MAP_FILE
4634static union trace_enum_map_item *
4635update_enum_map(union trace_enum_map_item *ptr)
4636{
4637 if (!ptr->map.enum_string) {
4638 if (ptr->tail.next) {
4639 ptr = ptr->tail.next;
4640 /* Set ptr to the next real item (skip head) */
4641 ptr++;
4642 } else
4643 return NULL;
4644 }
4645 return ptr;
4646}
4647
4648static void *enum_map_next(struct seq_file *m, void *v, loff_t *pos)
4649{
4650 union trace_enum_map_item *ptr = v;
4651
4652 /*
4653 * Paranoid! If ptr points to end, we don't want to increment past it.
4654 * This really should never happen.
4655 */
4656 ptr = update_enum_map(ptr);
4657 if (WARN_ON_ONCE(!ptr))
4658 return NULL;
4659
4660 ptr++;
4661
4662 (*pos)++;
4663
4664 ptr = update_enum_map(ptr);
4665
4666 return ptr;
4667}
4668
4669static void *enum_map_start(struct seq_file *m, loff_t *pos)
4670{
4671 union trace_enum_map_item *v;
4672 loff_t l = 0;
4673
4674 mutex_lock(&trace_enum_mutex);
4675
4676 v = trace_enum_maps;
4677 if (v)
4678 v++;
4679
4680 while (v && l < *pos) {
4681 v = enum_map_next(m, v, &l);
4682 }
4683
4684 return v;
4685}
4686
4687static void enum_map_stop(struct seq_file *m, void *v)
4688{
4689 mutex_unlock(&trace_enum_mutex);
4690}
4691
4692static int enum_map_show(struct seq_file *m, void *v)
4693{
4694 union trace_enum_map_item *ptr = v;
4695
4696 seq_printf(m, "%s %ld (%s)\n",
4697 ptr->map.enum_string, ptr->map.enum_value,
4698 ptr->map.system);
4699
4700 return 0;
4701}
4702
4703static const struct seq_operations tracing_enum_map_seq_ops = {
4704 .start = enum_map_start,
4705 .next = enum_map_next,
4706 .stop = enum_map_stop,
4707 .show = enum_map_show,
4708};
4709
4710static int tracing_enum_map_open(struct inode *inode, struct file *filp)
4711{
4712 if (tracing_disabled)
4713 return -ENODEV;
4714
4715 return seq_open(filp, &tracing_enum_map_seq_ops);
4716}
4717
4718static const struct file_operations tracing_enum_map_fops = {
4719 .open = tracing_enum_map_open,
4720 .read = seq_read,
4721 .llseek = seq_lseek,
4722 .release = seq_release,
4723};
4724
4725static inline union trace_enum_map_item *
4726trace_enum_jmp_to_tail(union trace_enum_map_item *ptr)
4727{
4728 /* Return tail of array given the head */
4729 return ptr + ptr->head.length + 1;
4730}
4731
4732static void
4733trace_insert_enum_map_file(struct module *mod, struct trace_enum_map **start,
4734 int len)
4735{
4736 struct trace_enum_map **stop;
4737 struct trace_enum_map **map;
4738 union trace_enum_map_item *map_array;
4739 union trace_enum_map_item *ptr;
4740
4741 stop = start + len;
4742
4743 /*
4744 * The trace_enum_maps contains the map plus a head and tail item,
4745 * where the head holds the module and length of array, and the
4746 * tail holds a pointer to the next list.
4747 */
4748 map_array = kmalloc(sizeof(*map_array) * (len + 2), GFP_KERNEL);
4749 if (!map_array) {
4750 pr_warn("Unable to allocate trace enum mapping\n");
4751 return;
4752 }
4753
4754 mutex_lock(&trace_enum_mutex);
4755
4756 if (!trace_enum_maps)
4757 trace_enum_maps = map_array;
4758 else {
4759 ptr = trace_enum_maps;
4760 for (;;) {
4761 ptr = trace_enum_jmp_to_tail(ptr);
4762 if (!ptr->tail.next)
4763 break;
4764 ptr = ptr->tail.next;
4765
4766 }
4767 ptr->tail.next = map_array;
4768 }
4769 map_array->head.mod = mod;
4770 map_array->head.length = len;
4771 map_array++;
4772
4773 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
4774 map_array->map = **map;
4775 map_array++;
4776 }
4777 memset(map_array, 0, sizeof(*map_array));
4778
4779 mutex_unlock(&trace_enum_mutex);
4780}
4781
4782static void trace_create_enum_file(struct dentry *d_tracer)
4783{
4784 trace_create_file("enum_map", 0444, d_tracer,
4785 NULL, &tracing_enum_map_fops);
4786}
4787
4788#else /* CONFIG_TRACE_ENUM_MAP_FILE */
4789static inline void trace_create_enum_file(struct dentry *d_tracer) { }
4790static inline void trace_insert_enum_map_file(struct module *mod,
4791 struct trace_enum_map **start, int len) { }
4792#endif /* !CONFIG_TRACE_ENUM_MAP_FILE */
4793
4794static void trace_insert_enum_map(struct module *mod,
4795 struct trace_enum_map **start, int len)
4796{
4797 struct trace_enum_map **map;
4798
4799 if (len <= 0)
4800 return;
4801
4802 map = start;
4803
4804 trace_event_enum_update(map, len);
4805
4806 trace_insert_enum_map_file(mod, start, len);
4807}
4808
4809static ssize_t
4810tracing_set_trace_read(struct file *filp, char __user *ubuf,
4811 size_t cnt, loff_t *ppos)
4812{
4813 struct trace_array *tr = filp->private_data;
4814 char buf[MAX_TRACER_SIZE+2];
4815 int r;
4816
4817 mutex_lock(&trace_types_lock);
4818 r = sprintf(buf, "%s\n", tr->current_trace->name);
4819 mutex_unlock(&trace_types_lock);
4820
4821 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4822}
4823
4824int tracer_init(struct tracer *t, struct trace_array *tr)
4825{
4826 tracing_reset_online_cpus(&tr->trace_buffer);
4827 return t->init(tr);
4828}
4829
4830static void set_buffer_entries(struct trace_buffer *buf, unsigned long val)
4831{
4832 int cpu;
4833
4834 for_each_tracing_cpu(cpu)
4835 per_cpu_ptr(buf->data, cpu)->entries = val;
4836}
4837
4838#ifdef CONFIG_TRACER_MAX_TRACE
4839/* resize @tr's buffer to the size of @size_tr's entries */
4840static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
4841 struct trace_buffer *size_buf, int cpu_id)
4842{
4843 int cpu, ret = 0;
4844
4845 if (cpu_id == RING_BUFFER_ALL_CPUS) {
4846 for_each_tracing_cpu(cpu) {
4847 ret = ring_buffer_resize(trace_buf->buffer,
4848 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
4849 if (ret < 0)
4850 break;
4851 per_cpu_ptr(trace_buf->data, cpu)->entries =
4852 per_cpu_ptr(size_buf->data, cpu)->entries;
4853 }
4854 } else {
4855 ret = ring_buffer_resize(trace_buf->buffer,
4856 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
4857 if (ret == 0)
4858 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
4859 per_cpu_ptr(size_buf->data, cpu_id)->entries;
4860 }
4861
4862 return ret;
4863}
4864#endif /* CONFIG_TRACER_MAX_TRACE */
4865
4866static int __tracing_resize_ring_buffer(struct trace_array *tr,
4867 unsigned long size, int cpu)
4868{
4869 int ret;
4870
4871 /*
4872 * If kernel or user changes the size of the ring buffer
4873 * we use the size that was given, and we can forget about
4874 * expanding it later.
4875 */
4876 ring_buffer_expanded = true;
4877
4878 /* May be called before buffers are initialized */
4879 if (!tr->trace_buffer.buffer)
4880 return 0;
4881
4882 ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu);
4883 if (ret < 0)
4884 return ret;
4885
4886#ifdef CONFIG_TRACER_MAX_TRACE
4887 if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
4888 !tr->current_trace->use_max_tr)
4889 goto out;
4890
4891 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
4892 if (ret < 0) {
4893 int r = resize_buffer_duplicate_size(&tr->trace_buffer,
4894 &tr->trace_buffer, cpu);
4895 if (r < 0) {
4896 /*
4897 * AARGH! We are left with different
4898 * size max buffer!!!!
4899 * The max buffer is our "snapshot" buffer.
4900 * When a tracer needs a snapshot (one of the
4901 * latency tracers), it swaps the max buffer
4902 * with the saved snap shot. We succeeded to
4903 * update the size of the main buffer, but failed to
4904 * update the size of the max buffer. But when we tried
4905 * to reset the main buffer to the original size, we
4906 * failed there too. This is very unlikely to
4907 * happen, but if it does, warn and kill all
4908 * tracing.
4909 */
4910 WARN_ON(1);
4911 tracing_disabled = 1;
4912 }
4913 return ret;
4914 }
4915
4916 if (cpu == RING_BUFFER_ALL_CPUS)
4917 set_buffer_entries(&tr->max_buffer, size);
4918 else
4919 per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
4920
4921 out:
4922#endif /* CONFIG_TRACER_MAX_TRACE */
4923
4924 if (cpu == RING_BUFFER_ALL_CPUS)
4925 set_buffer_entries(&tr->trace_buffer, size);
4926 else
4927 per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size;
4928
4929 return ret;
4930}
4931
4932static ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
4933 unsigned long size, int cpu_id)
4934{
4935 int ret = size;
4936
4937 mutex_lock(&trace_types_lock);
4938
4939 if (cpu_id != RING_BUFFER_ALL_CPUS) {
4940 /* make sure, this cpu is enabled in the mask */
4941 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
4942 ret = -EINVAL;
4943 goto out;
4944 }
4945 }
4946
4947 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
4948 if (ret < 0)
4949 ret = -ENOMEM;
4950
4951out:
4952 mutex_unlock(&trace_types_lock);
4953
4954 return ret;
4955}
4956
4957
4958/**
4959 * tracing_update_buffers - used by tracing facility to expand ring buffers
4960 *
4961 * To save on memory when the tracing is never used on a system with it
4962 * configured in. The ring buffers are set to a minimum size. But once
4963 * a user starts to use the tracing facility, then they need to grow
4964 * to their default size.
4965 *
4966 * This function is to be called when a tracer is about to be used.
4967 */
4968int tracing_update_buffers(void)
4969{
4970 int ret = 0;
4971
4972 mutex_lock(&trace_types_lock);
4973 if (!ring_buffer_expanded)
4974 ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
4975 RING_BUFFER_ALL_CPUS);
4976 mutex_unlock(&trace_types_lock);
4977
4978 return ret;
4979}
4980
4981struct trace_option_dentry;
4982
4983static void
4984create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
4985
4986/*
4987 * Used to clear out the tracer before deletion of an instance.
4988 * Must have trace_types_lock held.
4989 */
4990static void tracing_set_nop(struct trace_array *tr)
4991{
4992 if (tr->current_trace == &nop_trace)
4993 return;
4994
4995 tr->current_trace->enabled--;
4996
4997 if (tr->current_trace->reset)
4998 tr->current_trace->reset(tr);
4999
5000 tr->current_trace = &nop_trace;
5001}
5002
5003static void add_tracer_options(struct trace_array *tr, struct tracer *t)
5004{
5005 /* Only enable if the directory has been created already. */
5006 if (!tr->dir)
5007 return;
5008
5009 create_trace_option_files(tr, t);
5010}
5011
5012static int tracing_set_tracer(struct trace_array *tr, const char *buf)
5013{
5014 struct tracer *t;
5015#ifdef CONFIG_TRACER_MAX_TRACE
5016 bool had_max_tr;
5017#endif
5018 int ret = 0;
5019
5020 mutex_lock(&trace_types_lock);
5021
5022 if (!ring_buffer_expanded) {
5023 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
5024 RING_BUFFER_ALL_CPUS);
5025 if (ret < 0)
5026 goto out;
5027 ret = 0;
5028 }
5029
5030 for (t = trace_types; t; t = t->next) {
5031 if (strcmp(t->name, buf) == 0)
5032 break;
5033 }
5034 if (!t) {
5035 ret = -EINVAL;
5036 goto out;
5037 }
5038 if (t == tr->current_trace)
5039 goto out;
5040
5041 /* Some tracers are only allowed for the top level buffer */
5042 if (!trace_ok_for_array(t, tr)) {
5043 ret = -EINVAL;
5044 goto out;
5045 }
5046
5047 /* If trace pipe files are being read, we can't change the tracer */
5048 if (tr->current_trace->ref) {
5049 ret = -EBUSY;
5050 goto out;
5051 }
5052
5053 trace_branch_disable();
5054
5055 tr->current_trace->enabled--;
5056
5057 if (tr->current_trace->reset)
5058 tr->current_trace->reset(tr);
5059
5060 /* Current trace needs to be nop_trace before synchronize_sched */
5061 tr->current_trace = &nop_trace;
5062
5063#ifdef CONFIG_TRACER_MAX_TRACE
5064 had_max_tr = tr->allocated_snapshot;
5065
5066 if (had_max_tr && !t->use_max_tr) {
5067 /*
5068 * We need to make sure that the update_max_tr sees that
5069 * current_trace changed to nop_trace to keep it from
5070 * swapping the buffers after we resize it.
5071 * The update_max_tr is called from interrupts disabled
5072 * so a synchronized_sched() is sufficient.
5073 */
5074 synchronize_sched();
5075 free_snapshot(tr);
5076 }
5077#endif
5078
5079#ifdef CONFIG_TRACER_MAX_TRACE
5080 if (t->use_max_tr && !had_max_tr) {
5081 ret = alloc_snapshot(tr);
5082 if (ret < 0)
5083 goto out;
5084 }
5085#endif
5086
5087 if (t->init) {
5088 ret = tracer_init(t, tr);
5089 if (ret)
5090 goto out;
5091 }
5092
5093 tr->current_trace = t;
5094 tr->current_trace->enabled++;
5095 trace_branch_enable(tr);
5096 out:
5097 mutex_unlock(&trace_types_lock);
5098
5099 return ret;
5100}
5101
5102static ssize_t
5103tracing_set_trace_write(struct file *filp, const char __user *ubuf,
5104 size_t cnt, loff_t *ppos)
5105{
5106 struct trace_array *tr = filp->private_data;
5107 char buf[MAX_TRACER_SIZE+1];
5108 int i;
5109 size_t ret;
5110 int err;
5111
5112 ret = cnt;
5113
5114 if (cnt > MAX_TRACER_SIZE)
5115 cnt = MAX_TRACER_SIZE;
5116
5117 if (copy_from_user(buf, ubuf, cnt))
5118 return -EFAULT;
5119
5120 buf[cnt] = 0;
5121
5122 /* strip ending whitespace. */
5123 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
5124 buf[i] = 0;
5125
5126 err = tracing_set_tracer(tr, buf);
5127 if (err)
5128 return err;
5129
5130 *ppos += ret;
5131
5132 return ret;
5133}
5134
5135static ssize_t
5136tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
5137 size_t cnt, loff_t *ppos)
5138{
5139 char buf[64];
5140 int r;
5141
5142 r = snprintf(buf, sizeof(buf), "%ld\n",
5143 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
5144 if (r > sizeof(buf))
5145 r = sizeof(buf);
5146 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5147}
5148
5149static ssize_t
5150tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
5151 size_t cnt, loff_t *ppos)
5152{
5153 unsigned long val;
5154 int ret;
5155
5156 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5157 if (ret)
5158 return ret;
5159
5160 *ptr = val * 1000;
5161
5162 return cnt;
5163}
5164
5165static ssize_t
5166tracing_thresh_read(struct file *filp, char __user *ubuf,
5167 size_t cnt, loff_t *ppos)
5168{
5169 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
5170}
5171
5172static ssize_t
5173tracing_thresh_write(struct file *filp, const char __user *ubuf,
5174 size_t cnt, loff_t *ppos)
5175{
5176 struct trace_array *tr = filp->private_data;
5177 int ret;
5178
5179 mutex_lock(&trace_types_lock);
5180 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
5181 if (ret < 0)
5182 goto out;
5183
5184 if (tr->current_trace->update_thresh) {
5185 ret = tr->current_trace->update_thresh(tr);
5186 if (ret < 0)
5187 goto out;
5188 }
5189
5190 ret = cnt;
5191out:
5192 mutex_unlock(&trace_types_lock);
5193
5194 return ret;
5195}
5196
5197#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
5198
5199static ssize_t
5200tracing_max_lat_read(struct file *filp, char __user *ubuf,
5201 size_t cnt, loff_t *ppos)
5202{
5203 return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
5204}
5205
5206static ssize_t
5207tracing_max_lat_write(struct file *filp, const char __user *ubuf,
5208 size_t cnt, loff_t *ppos)
5209{
5210 return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
5211}
5212
5213#endif
5214
5215static int tracing_open_pipe(struct inode *inode, struct file *filp)
5216{
5217 struct trace_array *tr = inode->i_private;
5218 struct trace_iterator *iter;
5219 int ret = 0;
5220
5221 if (tracing_disabled)
5222 return -ENODEV;
5223
5224 if (trace_array_get(tr) < 0)
5225 return -ENODEV;
5226
5227 mutex_lock(&trace_types_lock);
5228
5229 /* create a buffer to store the information to pass to userspace */
5230 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
5231 if (!iter) {
5232 ret = -ENOMEM;
5233 __trace_array_put(tr);
5234 goto out;
5235 }
5236
5237 trace_seq_init(&iter->seq);
5238 iter->trace = tr->current_trace;
5239
5240 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
5241 ret = -ENOMEM;
5242 goto fail;
5243 }
5244
5245 /* trace pipe does not show start of buffer */
5246 cpumask_setall(iter->started);
5247
5248 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
5249 iter->iter_flags |= TRACE_FILE_LAT_FMT;
5250
5251 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
5252 if (trace_clocks[tr->clock_id].in_ns)
5253 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
5254
5255 iter->tr = tr;
5256 iter->trace_buffer = &tr->trace_buffer;
5257 iter->cpu_file = tracing_get_cpu(inode);
5258 mutex_init(&iter->mutex);
5259 filp->private_data = iter;
5260
5261 if (iter->trace->pipe_open)
5262 iter->trace->pipe_open(iter);
5263
5264 nonseekable_open(inode, filp);
5265
5266 tr->current_trace->ref++;
5267out:
5268 mutex_unlock(&trace_types_lock);
5269 return ret;
5270
5271fail:
5272 kfree(iter->trace);
5273 kfree(iter);
5274 __trace_array_put(tr);
5275 mutex_unlock(&trace_types_lock);
5276 return ret;
5277}
5278
5279static int tracing_release_pipe(struct inode *inode, struct file *file)
5280{
5281 struct trace_iterator *iter = file->private_data;
5282 struct trace_array *tr = inode->i_private;
5283
5284 mutex_lock(&trace_types_lock);
5285
5286 tr->current_trace->ref--;
5287
5288 if (iter->trace->pipe_close)
5289 iter->trace->pipe_close(iter);
5290
5291 mutex_unlock(&trace_types_lock);
5292
5293 free_cpumask_var(iter->started);
5294 mutex_destroy(&iter->mutex);
5295 kfree(iter);
5296
5297 trace_array_put(tr);
5298
5299 return 0;
5300}
5301
5302static unsigned int
5303trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
5304{
5305 struct trace_array *tr = iter->tr;
5306
5307 /* Iterators are static, they should be filled or empty */
5308 if (trace_buffer_iter(iter, iter->cpu_file))
5309 return POLLIN | POLLRDNORM;
5310
5311 if (tr->trace_flags & TRACE_ITER_BLOCK)
5312 /*
5313 * Always select as readable when in blocking mode
5314 */
5315 return POLLIN | POLLRDNORM;
5316 else
5317 return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file,
5318 filp, poll_table);
5319}
5320
5321static unsigned int
5322tracing_poll_pipe(struct file *filp, poll_table *poll_table)
5323{
5324 struct trace_iterator *iter = filp->private_data;
5325
5326 return trace_poll(iter, filp, poll_table);
5327}
5328
5329/* Must be called with iter->mutex held. */
5330static int tracing_wait_pipe(struct file *filp)
5331{
5332 struct trace_iterator *iter = filp->private_data;
5333 int ret;
5334
5335 while (trace_empty(iter)) {
5336
5337 if ((filp->f_flags & O_NONBLOCK)) {
5338 return -EAGAIN;
5339 }
5340
5341 /*
5342 * We block until we read something and tracing is disabled.
5343 * We still block if tracing is disabled, but we have never
5344 * read anything. This allows a user to cat this file, and
5345 * then enable tracing. But after we have read something,
5346 * we give an EOF when tracing is again disabled.
5347 *
5348 * iter->pos will be 0 if we haven't read anything.
5349 */
5350 if (!tracing_is_on() && iter->pos)
5351 break;
5352
5353 mutex_unlock(&iter->mutex);
5354
5355 ret = wait_on_pipe(iter, false);
5356
5357 mutex_lock(&iter->mutex);
5358
5359 if (ret)
5360 return ret;
5361 }
5362
5363 return 1;
5364}
5365
5366/*
5367 * Consumer reader.
5368 */
5369static ssize_t
5370tracing_read_pipe(struct file *filp, char __user *ubuf,
5371 size_t cnt, loff_t *ppos)
5372{
5373 struct trace_iterator *iter = filp->private_data;
5374 ssize_t sret;
5375
5376 /*
5377 * Avoid more than one consumer on a single file descriptor
5378 * This is just a matter of traces coherency, the ring buffer itself
5379 * is protected.
5380 */
5381 mutex_lock(&iter->mutex);
5382
5383 /* return any leftover data */
5384 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
5385 if (sret != -EBUSY)
5386 goto out;
5387
5388 trace_seq_init(&iter->seq);
5389
5390 if (iter->trace->read) {
5391 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
5392 if (sret)
5393 goto out;
5394 }
5395
5396waitagain:
5397 sret = tracing_wait_pipe(filp);
5398 if (sret <= 0)
5399 goto out;
5400
5401 /* stop when tracing is finished */
5402 if (trace_empty(iter)) {
5403 sret = 0;
5404 goto out;
5405 }
5406
5407 if (cnt >= PAGE_SIZE)
5408 cnt = PAGE_SIZE - 1;
5409
5410 /* reset all but tr, trace, and overruns */
5411 memset(&iter->seq, 0,
5412 sizeof(struct trace_iterator) -
5413 offsetof(struct trace_iterator, seq));
5414 cpumask_clear(iter->started);
5415 iter->pos = -1;
5416
5417 trace_event_read_lock();
5418 trace_access_lock(iter->cpu_file);
5419 while (trace_find_next_entry_inc(iter) != NULL) {
5420 enum print_line_t ret;
5421 int save_len = iter->seq.seq.len;
5422
5423 ret = print_trace_line(iter);
5424 if (ret == TRACE_TYPE_PARTIAL_LINE) {
5425 /* don't print partial lines */
5426 iter->seq.seq.len = save_len;
5427 break;
5428 }
5429 if (ret != TRACE_TYPE_NO_CONSUME)
5430 trace_consume(iter);
5431
5432 if (trace_seq_used(&iter->seq) >= cnt)
5433 break;
5434
5435 /*
5436 * Setting the full flag means we reached the trace_seq buffer
5437 * size and we should leave by partial output condition above.
5438 * One of the trace_seq_* functions is not used properly.
5439 */
5440 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
5441 iter->ent->type);
5442 }
5443 trace_access_unlock(iter->cpu_file);
5444 trace_event_read_unlock();
5445
5446 /* Now copy what we have to the user */
5447 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
5448 if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
5449 trace_seq_init(&iter->seq);
5450
5451 /*
5452 * If there was nothing to send to user, in spite of consuming trace
5453 * entries, go back to wait for more entries.
5454 */
5455 if (sret == -EBUSY)
5456 goto waitagain;
5457
5458out:
5459 mutex_unlock(&iter->mutex);
5460
5461 return sret;
5462}
5463
5464static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
5465 unsigned int idx)
5466{
5467 __free_page(spd->pages[idx]);
5468}
5469
5470static const struct pipe_buf_operations tracing_pipe_buf_ops = {
5471 .can_merge = 0,
5472 .confirm = generic_pipe_buf_confirm,
5473 .release = generic_pipe_buf_release,
5474 .steal = generic_pipe_buf_steal,
5475 .get = generic_pipe_buf_get,
5476};
5477
5478static size_t
5479tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
5480{
5481 size_t count;
5482 int save_len;
5483 int ret;
5484
5485 /* Seq buffer is page-sized, exactly what we need. */
5486 for (;;) {
5487 save_len = iter->seq.seq.len;
5488 ret = print_trace_line(iter);
5489
5490 if (trace_seq_has_overflowed(&iter->seq)) {
5491 iter->seq.seq.len = save_len;
5492 break;
5493 }
5494
5495 /*
5496 * This should not be hit, because it should only
5497 * be set if the iter->seq overflowed. But check it
5498 * anyway to be safe.
5499 */
5500 if (ret == TRACE_TYPE_PARTIAL_LINE) {
5501 iter->seq.seq.len = save_len;
5502 break;
5503 }
5504
5505 count = trace_seq_used(&iter->seq) - save_len;
5506 if (rem < count) {
5507 rem = 0;
5508 iter->seq.seq.len = save_len;
5509 break;
5510 }
5511
5512 if (ret != TRACE_TYPE_NO_CONSUME)
5513 trace_consume(iter);
5514 rem -= count;
5515 if (!trace_find_next_entry_inc(iter)) {
5516 rem = 0;
5517 iter->ent = NULL;
5518 break;
5519 }
5520 }
5521
5522 return rem;
5523}
5524
5525static ssize_t tracing_splice_read_pipe(struct file *filp,
5526 loff_t *ppos,
5527 struct pipe_inode_info *pipe,
5528 size_t len,
5529 unsigned int flags)
5530{
5531 struct page *pages_def[PIPE_DEF_BUFFERS];
5532 struct partial_page partial_def[PIPE_DEF_BUFFERS];
5533 struct trace_iterator *iter = filp->private_data;
5534 struct splice_pipe_desc spd = {
5535 .pages = pages_def,
5536 .partial = partial_def,
5537 .nr_pages = 0, /* This gets updated below. */
5538 .nr_pages_max = PIPE_DEF_BUFFERS,
5539 .flags = flags,
5540 .ops = &tracing_pipe_buf_ops,
5541 .spd_release = tracing_spd_release_pipe,
5542 };
5543 ssize_t ret;
5544 size_t rem;
5545 unsigned int i;
5546
5547 if (splice_grow_spd(pipe, &spd))
5548 return -ENOMEM;
5549
5550 mutex_lock(&iter->mutex);
5551
5552 if (iter->trace->splice_read) {
5553 ret = iter->trace->splice_read(iter, filp,
5554 ppos, pipe, len, flags);
5555 if (ret)
5556 goto out_err;
5557 }
5558
5559 ret = tracing_wait_pipe(filp);
5560 if (ret <= 0)
5561 goto out_err;
5562
5563 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
5564 ret = -EFAULT;
5565 goto out_err;
5566 }
5567
5568 trace_event_read_lock();
5569 trace_access_lock(iter->cpu_file);
5570
5571 /* Fill as many pages as possible. */
5572 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
5573 spd.pages[i] = alloc_page(GFP_KERNEL);
5574 if (!spd.pages[i])
5575 break;
5576
5577 rem = tracing_fill_pipe_page(rem, iter);
5578
5579 /* Copy the data into the page, so we can start over. */
5580 ret = trace_seq_to_buffer(&iter->seq,
5581 page_address(spd.pages[i]),
5582 trace_seq_used(&iter->seq));
5583 if (ret < 0) {
5584 __free_page(spd.pages[i]);
5585 break;
5586 }
5587 spd.partial[i].offset = 0;
5588 spd.partial[i].len = trace_seq_used(&iter->seq);
5589
5590 trace_seq_init(&iter->seq);
5591 }
5592
5593 trace_access_unlock(iter->cpu_file);
5594 trace_event_read_unlock();
5595 mutex_unlock(&iter->mutex);
5596
5597 spd.nr_pages = i;
5598
5599 if (i)
5600 ret = splice_to_pipe(pipe, &spd);
5601 else
5602 ret = 0;
5603out:
5604 splice_shrink_spd(&spd);
5605 return ret;
5606
5607out_err:
5608 mutex_unlock(&iter->mutex);
5609 goto out;
5610}
5611
5612static ssize_t
5613tracing_entries_read(struct file *filp, char __user *ubuf,
5614 size_t cnt, loff_t *ppos)
5615{
5616 struct inode *inode = file_inode(filp);
5617 struct trace_array *tr = inode->i_private;
5618 int cpu = tracing_get_cpu(inode);
5619 char buf[64];
5620 int r = 0;
5621 ssize_t ret;
5622
5623 mutex_lock(&trace_types_lock);
5624
5625 if (cpu == RING_BUFFER_ALL_CPUS) {
5626 int cpu, buf_size_same;
5627 unsigned long size;
5628
5629 size = 0;
5630 buf_size_same = 1;
5631 /* check if all cpu sizes are same */
5632 for_each_tracing_cpu(cpu) {
5633 /* fill in the size from first enabled cpu */
5634 if (size == 0)
5635 size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries;
5636 if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) {
5637 buf_size_same = 0;
5638 break;
5639 }
5640 }
5641
5642 if (buf_size_same) {
5643 if (!ring_buffer_expanded)
5644 r = sprintf(buf, "%lu (expanded: %lu)\n",
5645 size >> 10,
5646 trace_buf_size >> 10);
5647 else
5648 r = sprintf(buf, "%lu\n", size >> 10);
5649 } else
5650 r = sprintf(buf, "X\n");
5651 } else
5652 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
5653
5654 mutex_unlock(&trace_types_lock);
5655
5656 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5657 return ret;
5658}
5659
5660static ssize_t
5661tracing_entries_write(struct file *filp, const char __user *ubuf,
5662 size_t cnt, loff_t *ppos)
5663{
5664 struct inode *inode = file_inode(filp);
5665 struct trace_array *tr = inode->i_private;
5666 unsigned long val;
5667 int ret;
5668
5669 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5670 if (ret)
5671 return ret;
5672
5673 /* must have at least 1 entry */
5674 if (!val)
5675 return -EINVAL;
5676
5677 /* value is in KB */
5678 val <<= 10;
5679 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
5680 if (ret < 0)
5681 return ret;
5682
5683 *ppos += cnt;
5684
5685 return cnt;
5686}
5687
5688static ssize_t
5689tracing_total_entries_read(struct file *filp, char __user *ubuf,
5690 size_t cnt, loff_t *ppos)
5691{
5692 struct trace_array *tr = filp->private_data;
5693 char buf[64];
5694 int r, cpu;
5695 unsigned long size = 0, expanded_size = 0;
5696
5697 mutex_lock(&trace_types_lock);
5698 for_each_tracing_cpu(cpu) {
5699 size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10;
5700 if (!ring_buffer_expanded)
5701 expanded_size += trace_buf_size >> 10;
5702 }
5703 if (ring_buffer_expanded)
5704 r = sprintf(buf, "%lu\n", size);
5705 else
5706 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
5707 mutex_unlock(&trace_types_lock);
5708
5709 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5710}
5711
5712static ssize_t
5713tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
5714 size_t cnt, loff_t *ppos)
5715{
5716 /*
5717 * There is no need to read what the user has written, this function
5718 * is just to make sure that there is no error when "echo" is used
5719 */
5720
5721 *ppos += cnt;
5722
5723 return cnt;
5724}
5725
5726static int
5727tracing_free_buffer_release(struct inode *inode, struct file *filp)
5728{
5729 struct trace_array *tr = inode->i_private;
5730
5731 /* disable tracing ? */
5732 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
5733 tracer_tracing_off(tr);
5734 /* resize the ring buffer to 0 */
5735 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
5736
5737 trace_array_put(tr);
5738
5739 return 0;
5740}
5741
5742static ssize_t
5743tracing_mark_write(struct file *filp, const char __user *ubuf,
5744 size_t cnt, loff_t *fpos)
5745{
5746 struct trace_array *tr = filp->private_data;
5747 struct ring_buffer_event *event;
5748 struct ring_buffer *buffer;
5749 struct print_entry *entry;
5750 unsigned long irq_flags;
5751 const char faulted[] = "<faulted>";
5752 ssize_t written;
5753 int size;
5754 int len;
5755
5756/* Used in tracing_mark_raw_write() as well */
5757#define FAULTED_SIZE (sizeof(faulted) - 1) /* '\0' is already accounted for */
5758
5759 if (tracing_disabled)
5760 return -EINVAL;
5761
5762 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
5763 return -EINVAL;
5764
5765 if (cnt > TRACE_BUF_SIZE)
5766 cnt = TRACE_BUF_SIZE;
5767
5768 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
5769
5770 local_save_flags(irq_flags);
5771 size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */
5772
5773 /* If less than "<faulted>", then make sure we can still add that */
5774 if (cnt < FAULTED_SIZE)
5775 size += FAULTED_SIZE - cnt;
5776
5777 buffer = tr->trace_buffer.buffer;
5778 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
5779 irq_flags, preempt_count());
5780 if (unlikely(!event))
5781 /* Ring buffer disabled, return as if not open for write */
5782 return -EBADF;
5783
5784 entry = ring_buffer_event_data(event);
5785 entry->ip = _THIS_IP_;
5786
5787 len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
5788 if (len) {
5789 memcpy(&entry->buf, faulted, FAULTED_SIZE);
5790 cnt = FAULTED_SIZE;
5791 written = -EFAULT;
5792 } else
5793 written = cnt;
5794 len = cnt;
5795
5796 if (entry->buf[cnt - 1] != '\n') {
5797 entry->buf[cnt] = '\n';
5798 entry->buf[cnt + 1] = '\0';
5799 } else
5800 entry->buf[cnt] = '\0';
5801
5802 __buffer_unlock_commit(buffer, event);
5803
5804 if (written > 0)
5805 *fpos += written;
5806
5807 return written;
5808}
5809
5810/* Limit it for now to 3K (including tag) */
5811#define RAW_DATA_MAX_SIZE (1024*3)
5812
5813static ssize_t
5814tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
5815 size_t cnt, loff_t *fpos)
5816{
5817 struct trace_array *tr = filp->private_data;
5818 struct ring_buffer_event *event;
5819 struct ring_buffer *buffer;
5820 struct raw_data_entry *entry;
5821 const char faulted[] = "<faulted>";
5822 unsigned long irq_flags;
5823 ssize_t written;
5824 int size;
5825 int len;
5826
5827#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
5828
5829 if (tracing_disabled)
5830 return -EINVAL;
5831
5832 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
5833 return -EINVAL;
5834
5835 /* The marker must at least have a tag id */
5836 if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE)
5837 return -EINVAL;
5838
5839 if (cnt > TRACE_BUF_SIZE)
5840 cnt = TRACE_BUF_SIZE;
5841
5842 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
5843
5844 local_save_flags(irq_flags);
5845 size = sizeof(*entry) + cnt;
5846 if (cnt < FAULT_SIZE_ID)
5847 size += FAULT_SIZE_ID - cnt;
5848
5849 buffer = tr->trace_buffer.buffer;
5850 event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
5851 irq_flags, preempt_count());
5852 if (!event)
5853 /* Ring buffer disabled, return as if not open for write */
5854 return -EBADF;
5855
5856 entry = ring_buffer_event_data(event);
5857
5858 len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
5859 if (len) {
5860 entry->id = -1;
5861 memcpy(&entry->buf, faulted, FAULTED_SIZE);
5862 written = -EFAULT;
5863 } else
5864 written = cnt;
5865
5866 __buffer_unlock_commit(buffer, event);
5867
5868 if (written > 0)
5869 *fpos += written;
5870
5871 return written;
5872}
5873
5874static int tracing_clock_show(struct seq_file *m, void *v)
5875{
5876 struct trace_array *tr = m->private;
5877 int i;
5878
5879 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
5880 seq_printf(m,
5881 "%s%s%s%s", i ? " " : "",
5882 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
5883 i == tr->clock_id ? "]" : "");
5884 seq_putc(m, '\n');
5885
5886 return 0;
5887}
5888
5889static int tracing_set_clock(struct trace_array *tr, const char *clockstr)
5890{
5891 int i;
5892
5893 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
5894 if (strcmp(trace_clocks[i].name, clockstr) == 0)
5895 break;
5896 }
5897 if (i == ARRAY_SIZE(trace_clocks))
5898 return -EINVAL;
5899
5900 mutex_lock(&trace_types_lock);
5901
5902 tr->clock_id = i;
5903
5904 ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func);
5905
5906 /*
5907 * New clock may not be consistent with the previous clock.
5908 * Reset the buffer so that it doesn't have incomparable timestamps.
5909 */
5910 tracing_reset_online_cpus(&tr->trace_buffer);
5911
5912#ifdef CONFIG_TRACER_MAX_TRACE
5913 if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
5914 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
5915 tracing_reset_online_cpus(&tr->max_buffer);
5916#endif
5917
5918 mutex_unlock(&trace_types_lock);
5919
5920 return 0;
5921}
5922
5923static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
5924 size_t cnt, loff_t *fpos)
5925{
5926 struct seq_file *m = filp->private_data;
5927 struct trace_array *tr = m->private;
5928 char buf[64];
5929 const char *clockstr;
5930 int ret;
5931
5932 if (cnt >= sizeof(buf))
5933 return -EINVAL;
5934
5935 if (copy_from_user(buf, ubuf, cnt))
5936 return -EFAULT;
5937
5938 buf[cnt] = 0;
5939
5940 clockstr = strstrip(buf);
5941
5942 ret = tracing_set_clock(tr, clockstr);
5943 if (ret)
5944 return ret;
5945
5946 *fpos += cnt;
5947
5948 return cnt;
5949}
5950
5951static int tracing_clock_open(struct inode *inode, struct file *file)
5952{
5953 struct trace_array *tr = inode->i_private;
5954 int ret;
5955
5956 if (tracing_disabled)
5957 return -ENODEV;
5958
5959 if (trace_array_get(tr))
5960 return -ENODEV;
5961
5962 ret = single_open(file, tracing_clock_show, inode->i_private);
5963 if (ret < 0)
5964 trace_array_put(tr);
5965
5966 return ret;
5967}
5968
5969struct ftrace_buffer_info {
5970 struct trace_iterator iter;
5971 void *spare;
5972 unsigned int read;
5973};
5974
5975#ifdef CONFIG_TRACER_SNAPSHOT
5976static int tracing_snapshot_open(struct inode *inode, struct file *file)
5977{
5978 struct trace_array *tr = inode->i_private;
5979 struct trace_iterator *iter;
5980 struct seq_file *m;
5981 int ret = 0;
5982
5983 if (trace_array_get(tr) < 0)
5984 return -ENODEV;
5985
5986 if (file->f_mode & FMODE_READ) {
5987 iter = __tracing_open(inode, file, true);
5988 if (IS_ERR(iter))
5989 ret = PTR_ERR(iter);
5990 } else {
5991 /* Writes still need the seq_file to hold the private data */
5992 ret = -ENOMEM;
5993 m = kzalloc(sizeof(*m), GFP_KERNEL);
5994 if (!m)
5995 goto out;
5996 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
5997 if (!iter) {
5998 kfree(m);
5999 goto out;
6000 }
6001 ret = 0;
6002
6003 iter->tr = tr;
6004 iter->trace_buffer = &tr->max_buffer;
6005 iter->cpu_file = tracing_get_cpu(inode);
6006 m->private = iter;
6007 file->private_data = m;
6008 }
6009out:
6010 if (ret < 0)
6011 trace_array_put(tr);
6012
6013 return ret;
6014}
6015
6016static ssize_t
6017tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
6018 loff_t *ppos)
6019{
6020 struct seq_file *m = filp->private_data;
6021 struct trace_iterator *iter = m->private;
6022 struct trace_array *tr = iter->tr;
6023 unsigned long val;
6024 int ret;
6025
6026 ret = tracing_update_buffers();
6027 if (ret < 0)
6028 return ret;
6029
6030 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6031 if (ret)
6032 return ret;
6033
6034 mutex_lock(&trace_types_lock);
6035
6036 if (tr->current_trace->use_max_tr) {
6037 ret = -EBUSY;
6038 goto out;
6039 }
6040
6041 switch (val) {
6042 case 0:
6043 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
6044 ret = -EINVAL;
6045 break;
6046 }
6047 if (tr->allocated_snapshot)
6048 free_snapshot(tr);
6049 break;
6050 case 1:
6051/* Only allow per-cpu swap if the ring buffer supports it */
6052#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
6053 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
6054 ret = -EINVAL;
6055 break;
6056 }
6057#endif
6058 if (!tr->allocated_snapshot) {
6059 ret = alloc_snapshot(tr);
6060 if (ret < 0)
6061 break;
6062 }
6063 local_irq_disable();
6064 /* Now, we're going to swap */
6065 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
6066 update_max_tr(tr, current, smp_processor_id());
6067 else
6068 update_max_tr_single(tr, current, iter->cpu_file);
6069 local_irq_enable();
6070 break;
6071 default:
6072 if (tr->allocated_snapshot) {
6073 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
6074 tracing_reset_online_cpus(&tr->max_buffer);
6075 else
6076 tracing_reset(&tr->max_buffer, iter->cpu_file);
6077 }
6078 break;
6079 }
6080
6081 if (ret >= 0) {
6082 *ppos += cnt;
6083 ret = cnt;
6084 }
6085out:
6086 mutex_unlock(&trace_types_lock);
6087 return ret;
6088}
6089
6090static int tracing_snapshot_release(struct inode *inode, struct file *file)
6091{
6092 struct seq_file *m = file->private_data;
6093 int ret;
6094
6095 ret = tracing_release(inode, file);
6096
6097 if (file->f_mode & FMODE_READ)
6098 return ret;
6099
6100 /* If write only, the seq_file is just a stub */
6101 if (m)
6102 kfree(m->private);
6103 kfree(m);
6104
6105 return 0;
6106}
6107
6108static int tracing_buffers_open(struct inode *inode, struct file *filp);
6109static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
6110 size_t count, loff_t *ppos);
6111static int tracing_buffers_release(struct inode *inode, struct file *file);
6112static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
6113 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
6114
6115static int snapshot_raw_open(struct inode *inode, struct file *filp)
6116{
6117 struct ftrace_buffer_info *info;
6118 int ret;
6119
6120 ret = tracing_buffers_open(inode, filp);
6121 if (ret < 0)
6122 return ret;
6123
6124 info = filp->private_data;
6125
6126 if (info->iter.trace->use_max_tr) {
6127 tracing_buffers_release(inode, filp);
6128 return -EBUSY;
6129 }
6130
6131 info->iter.snapshot = true;
6132 info->iter.trace_buffer = &info->iter.tr->max_buffer;
6133
6134 return ret;
6135}
6136
6137#endif /* CONFIG_TRACER_SNAPSHOT */
6138
6139
6140static const struct file_operations tracing_thresh_fops = {
6141 .open = tracing_open_generic,
6142 .read = tracing_thresh_read,
6143 .write = tracing_thresh_write,
6144 .llseek = generic_file_llseek,
6145};
6146
6147#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
6148static const struct file_operations tracing_max_lat_fops = {
6149 .open = tracing_open_generic,
6150 .read = tracing_max_lat_read,
6151 .write = tracing_max_lat_write,
6152 .llseek = generic_file_llseek,
6153};
6154#endif
6155
6156static const struct file_operations set_tracer_fops = {
6157 .open = tracing_open_generic,
6158 .read = tracing_set_trace_read,
6159 .write = tracing_set_trace_write,
6160 .llseek = generic_file_llseek,
6161};
6162
6163static const struct file_operations tracing_pipe_fops = {
6164 .open = tracing_open_pipe,
6165 .poll = tracing_poll_pipe,
6166 .read = tracing_read_pipe,
6167 .splice_read = tracing_splice_read_pipe,
6168 .release = tracing_release_pipe,
6169 .llseek = no_llseek,
6170};
6171
6172static const struct file_operations tracing_entries_fops = {
6173 .open = tracing_open_generic_tr,
6174 .read = tracing_entries_read,
6175 .write = tracing_entries_write,
6176 .llseek = generic_file_llseek,
6177 .release = tracing_release_generic_tr,
6178};
6179
6180static const struct file_operations tracing_total_entries_fops = {
6181 .open = tracing_open_generic_tr,
6182 .read = tracing_total_entries_read,
6183 .llseek = generic_file_llseek,
6184 .release = tracing_release_generic_tr,
6185};
6186
6187static const struct file_operations tracing_free_buffer_fops = {
6188 .open = tracing_open_generic_tr,
6189 .write = tracing_free_buffer_write,
6190 .release = tracing_free_buffer_release,
6191};
6192
6193static const struct file_operations tracing_mark_fops = {
6194 .open = tracing_open_generic_tr,
6195 .write = tracing_mark_write,
6196 .llseek = generic_file_llseek,
6197 .release = tracing_release_generic_tr,
6198};
6199
6200static const struct file_operations tracing_mark_raw_fops = {
6201 .open = tracing_open_generic_tr,
6202 .write = tracing_mark_raw_write,
6203 .llseek = generic_file_llseek,
6204 .release = tracing_release_generic_tr,
6205};
6206
6207static const struct file_operations trace_clock_fops = {
6208 .open = tracing_clock_open,
6209 .read = seq_read,
6210 .llseek = seq_lseek,
6211 .release = tracing_single_release_tr,
6212 .write = tracing_clock_write,
6213};
6214
6215#ifdef CONFIG_TRACER_SNAPSHOT
6216static const struct file_operations snapshot_fops = {
6217 .open = tracing_snapshot_open,
6218 .read = seq_read,
6219 .write = tracing_snapshot_write,
6220 .llseek = tracing_lseek,
6221 .release = tracing_snapshot_release,
6222};
6223
6224static const struct file_operations snapshot_raw_fops = {
6225 .open = snapshot_raw_open,
6226 .read = tracing_buffers_read,
6227 .release = tracing_buffers_release,
6228 .splice_read = tracing_buffers_splice_read,
6229 .llseek = no_llseek,
6230};
6231
6232#endif /* CONFIG_TRACER_SNAPSHOT */
6233
6234static int tracing_buffers_open(struct inode *inode, struct file *filp)
6235{
6236 struct trace_array *tr = inode->i_private;
6237 struct ftrace_buffer_info *info;
6238 int ret;
6239
6240 if (tracing_disabled)
6241 return -ENODEV;
6242
6243 if (trace_array_get(tr) < 0)
6244 return -ENODEV;
6245
6246 info = kzalloc(sizeof(*info), GFP_KERNEL);
6247 if (!info) {
6248 trace_array_put(tr);
6249 return -ENOMEM;
6250 }
6251
6252 mutex_lock(&trace_types_lock);
6253
6254 info->iter.tr = tr;
6255 info->iter.cpu_file = tracing_get_cpu(inode);
6256 info->iter.trace = tr->current_trace;
6257 info->iter.trace_buffer = &tr->trace_buffer;
6258 info->spare = NULL;
6259 /* Force reading ring buffer for first read */
6260 info->read = (unsigned int)-1;
6261
6262 filp->private_data = info;
6263
6264 tr->current_trace->ref++;
6265
6266 mutex_unlock(&trace_types_lock);
6267
6268 ret = nonseekable_open(inode, filp);
6269 if (ret < 0)
6270 trace_array_put(tr);
6271
6272 return ret;
6273}
6274
6275static unsigned int
6276tracing_buffers_poll(struct file *filp, poll_table *poll_table)
6277{
6278 struct ftrace_buffer_info *info = filp->private_data;
6279 struct trace_iterator *iter = &info->iter;
6280
6281 return trace_poll(iter, filp, poll_table);
6282}
6283
6284static ssize_t
6285tracing_buffers_read(struct file *filp, char __user *ubuf,
6286 size_t count, loff_t *ppos)
6287{
6288 struct ftrace_buffer_info *info = filp->private_data;
6289 struct trace_iterator *iter = &info->iter;
6290 ssize_t ret;
6291 ssize_t size;
6292
6293 if (!count)
6294 return 0;
6295
6296#ifdef CONFIG_TRACER_MAX_TRACE
6297 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
6298 return -EBUSY;
6299#endif
6300
6301 if (!info->spare)
6302 info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
6303 iter->cpu_file);
6304 if (!info->spare)
6305 return -ENOMEM;
6306
6307 /* Do we have previous read data to read? */
6308 if (info->read < PAGE_SIZE)
6309 goto read;
6310
6311 again:
6312 trace_access_lock(iter->cpu_file);
6313 ret = ring_buffer_read_page(iter->trace_buffer->buffer,
6314 &info->spare,
6315 count,
6316 iter->cpu_file, 0);
6317 trace_access_unlock(iter->cpu_file);
6318
6319 if (ret < 0) {
6320 if (trace_empty(iter)) {
6321 if ((filp->f_flags & O_NONBLOCK))
6322 return -EAGAIN;
6323
6324 ret = wait_on_pipe(iter, false);
6325 if (ret)
6326 return ret;
6327
6328 goto again;
6329 }
6330 return 0;
6331 }
6332
6333 info->read = 0;
6334 read:
6335 size = PAGE_SIZE - info->read;
6336 if (size > count)
6337 size = count;
6338
6339 ret = copy_to_user(ubuf, info->spare + info->read, size);
6340 if (ret == size)
6341 return -EFAULT;
6342
6343 size -= ret;
6344
6345 *ppos += size;
6346 info->read += size;
6347
6348 return size;
6349}
6350
6351static int tracing_buffers_release(struct inode *inode, struct file *file)
6352{
6353 struct ftrace_buffer_info *info = file->private_data;
6354 struct trace_iterator *iter = &info->iter;
6355
6356 mutex_lock(&trace_types_lock);
6357
6358 iter->tr->current_trace->ref--;
6359
6360 __trace_array_put(iter->tr);
6361
6362 if (info->spare)
6363 ring_buffer_free_read_page(iter->trace_buffer->buffer, info->spare);
6364 kfree(info);
6365
6366 mutex_unlock(&trace_types_lock);
6367
6368 return 0;
6369}
6370
6371struct buffer_ref {
6372 struct ring_buffer *buffer;
6373 void *page;
6374 int ref;
6375};
6376
6377static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
6378 struct pipe_buffer *buf)
6379{
6380 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
6381
6382 if (--ref->ref)
6383 return;
6384
6385 ring_buffer_free_read_page(ref->buffer, ref->page);
6386 kfree(ref);
6387 buf->private = 0;
6388}
6389
6390static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
6391 struct pipe_buffer *buf)
6392{
6393 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
6394
6395 ref->ref++;
6396}
6397
6398/* Pipe buffer operations for a buffer. */
6399static const struct pipe_buf_operations buffer_pipe_buf_ops = {
6400 .can_merge = 0,
6401 .confirm = generic_pipe_buf_confirm,
6402 .release = buffer_pipe_buf_release,
6403 .steal = generic_pipe_buf_steal,
6404 .get = buffer_pipe_buf_get,
6405};
6406
6407/*
6408 * Callback from splice_to_pipe(), if we need to release some pages
6409 * at the end of the spd in case we error'ed out in filling the pipe.
6410 */
6411static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
6412{
6413 struct buffer_ref *ref =
6414 (struct buffer_ref *)spd->partial[i].private;
6415
6416 if (--ref->ref)
6417 return;
6418
6419 ring_buffer_free_read_page(ref->buffer, ref->page);
6420 kfree(ref);
6421 spd->partial[i].private = 0;
6422}
6423
6424static ssize_t
6425tracing_buffers_splice_read(struct file *file, loff_t *ppos,
6426 struct pipe_inode_info *pipe, size_t len,
6427 unsigned int flags)
6428{
6429 struct ftrace_buffer_info *info = file->private_data;
6430 struct trace_iterator *iter = &info->iter;
6431 struct partial_page partial_def[PIPE_DEF_BUFFERS];
6432 struct page *pages_def[PIPE_DEF_BUFFERS];
6433 struct splice_pipe_desc spd = {
6434 .pages = pages_def,
6435 .partial = partial_def,
6436 .nr_pages_max = PIPE_DEF_BUFFERS,
6437 .flags = flags,
6438 .ops = &buffer_pipe_buf_ops,
6439 .spd_release = buffer_spd_release,
6440 };
6441 struct buffer_ref *ref;
6442 int entries, size, i;
6443 ssize_t ret = 0;
6444
6445#ifdef CONFIG_TRACER_MAX_TRACE
6446 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
6447 return -EBUSY;
6448#endif
6449
6450 if (*ppos & (PAGE_SIZE - 1))
6451 return -EINVAL;
6452
6453 if (len & (PAGE_SIZE - 1)) {
6454 if (len < PAGE_SIZE)
6455 return -EINVAL;
6456 len &= PAGE_MASK;
6457 }
6458
6459 if (splice_grow_spd(pipe, &spd))
6460 return -ENOMEM;
6461
6462 again:
6463 trace_access_lock(iter->cpu_file);
6464 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
6465
6466 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
6467 struct page *page;
6468 int r;
6469
6470 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
6471 if (!ref) {
6472 ret = -ENOMEM;
6473 break;
6474 }
6475
6476 ref->ref = 1;
6477 ref->buffer = iter->trace_buffer->buffer;
6478 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
6479 if (!ref->page) {
6480 ret = -ENOMEM;
6481 kfree(ref);
6482 break;
6483 }
6484
6485 r = ring_buffer_read_page(ref->buffer, &ref->page,
6486 len, iter->cpu_file, 1);
6487 if (r < 0) {
6488 ring_buffer_free_read_page(ref->buffer, ref->page);
6489 kfree(ref);
6490 break;
6491 }
6492
6493 /*
6494 * zero out any left over data, this is going to
6495 * user land.
6496 */
6497 size = ring_buffer_page_len(ref->page);
6498 if (size < PAGE_SIZE)
6499 memset(ref->page + size, 0, PAGE_SIZE - size);
6500
6501 page = virt_to_page(ref->page);
6502
6503 spd.pages[i] = page;
6504 spd.partial[i].len = PAGE_SIZE;
6505 spd.partial[i].offset = 0;
6506 spd.partial[i].private = (unsigned long)ref;
6507 spd.nr_pages++;
6508 *ppos += PAGE_SIZE;
6509
6510 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
6511 }
6512
6513 trace_access_unlock(iter->cpu_file);
6514 spd.nr_pages = i;
6515
6516 /* did we read anything? */
6517 if (!spd.nr_pages) {
6518 if (ret)
6519 goto out;
6520
6521 ret = -EAGAIN;
6522 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
6523 goto out;
6524
6525 ret = wait_on_pipe(iter, true);
6526 if (ret)
6527 goto out;
6528
6529 goto again;
6530 }
6531
6532 ret = splice_to_pipe(pipe, &spd);
6533out:
6534 splice_shrink_spd(&spd);
6535
6536 return ret;
6537}
6538
6539static const struct file_operations tracing_buffers_fops = {
6540 .open = tracing_buffers_open,
6541 .read = tracing_buffers_read,
6542 .poll = tracing_buffers_poll,
6543 .release = tracing_buffers_release,
6544 .splice_read = tracing_buffers_splice_read,
6545 .llseek = no_llseek,
6546};
6547
6548static ssize_t
6549tracing_stats_read(struct file *filp, char __user *ubuf,
6550 size_t count, loff_t *ppos)
6551{
6552 struct inode *inode = file_inode(filp);
6553 struct trace_array *tr = inode->i_private;
6554 struct trace_buffer *trace_buf = &tr->trace_buffer;
6555 int cpu = tracing_get_cpu(inode);
6556 struct trace_seq *s;
6557 unsigned long cnt;
6558 unsigned long long t;
6559 unsigned long usec_rem;
6560
6561 s = kmalloc(sizeof(*s), GFP_KERNEL);
6562 if (!s)
6563 return -ENOMEM;
6564
6565 trace_seq_init(s);
6566
6567 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
6568 trace_seq_printf(s, "entries: %ld\n", cnt);
6569
6570 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
6571 trace_seq_printf(s, "overrun: %ld\n", cnt);
6572
6573 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
6574 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
6575
6576 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
6577 trace_seq_printf(s, "bytes: %ld\n", cnt);
6578
6579 if (trace_clocks[tr->clock_id].in_ns) {
6580 /* local or global for trace_clock */
6581 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
6582 usec_rem = do_div(t, USEC_PER_SEC);
6583 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
6584 t, usec_rem);
6585
6586 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu));
6587 usec_rem = do_div(t, USEC_PER_SEC);
6588 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
6589 } else {
6590 /* counter or tsc mode for trace_clock */
6591 trace_seq_printf(s, "oldest event ts: %llu\n",
6592 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
6593
6594 trace_seq_printf(s, "now ts: %llu\n",
6595 ring_buffer_time_stamp(trace_buf->buffer, cpu));
6596 }
6597
6598 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
6599 trace_seq_printf(s, "dropped events: %ld\n", cnt);
6600
6601 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
6602 trace_seq_printf(s, "read events: %ld\n", cnt);
6603
6604 count = simple_read_from_buffer(ubuf, count, ppos,
6605 s->buffer, trace_seq_used(s));
6606
6607 kfree(s);
6608
6609 return count;
6610}
6611
6612static const struct file_operations tracing_stats_fops = {
6613 .open = tracing_open_generic_tr,
6614 .read = tracing_stats_read,
6615 .llseek = generic_file_llseek,
6616 .release = tracing_release_generic_tr,
6617};
6618
6619#ifdef CONFIG_DYNAMIC_FTRACE
6620
6621int __weak ftrace_arch_read_dyn_info(char *buf, int size)
6622{
6623 return 0;
6624}
6625
6626static ssize_t
6627tracing_read_dyn_info(struct file *filp, char __user *ubuf,
6628 size_t cnt, loff_t *ppos)
6629{
6630 static char ftrace_dyn_info_buffer[1024];
6631 static DEFINE_MUTEX(dyn_info_mutex);
6632 unsigned long *p = filp->private_data;
6633 char *buf = ftrace_dyn_info_buffer;
6634 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
6635 int r;
6636
6637 mutex_lock(&dyn_info_mutex);
6638 r = sprintf(buf, "%ld ", *p);
6639
6640 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
6641 buf[r++] = '\n';
6642
6643 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6644
6645 mutex_unlock(&dyn_info_mutex);
6646
6647 return r;
6648}
6649
6650static const struct file_operations tracing_dyn_info_fops = {
6651 .open = tracing_open_generic,
6652 .read = tracing_read_dyn_info,
6653 .llseek = generic_file_llseek,
6654};
6655#endif /* CONFIG_DYNAMIC_FTRACE */
6656
6657#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
6658static void
6659ftrace_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
6660{
6661 tracing_snapshot();
6662}
6663
6664static void
6665ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
6666{
6667 unsigned long *count = (long *)data;
6668
6669 if (!*count)
6670 return;
6671
6672 if (*count != -1)
6673 (*count)--;
6674
6675 tracing_snapshot();
6676}
6677
6678static int
6679ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
6680 struct ftrace_probe_ops *ops, void *data)
6681{
6682 long count = (long)data;
6683
6684 seq_printf(m, "%ps:", (void *)ip);
6685
6686 seq_puts(m, "snapshot");
6687
6688 if (count == -1)
6689 seq_puts(m, ":unlimited\n");
6690 else
6691 seq_printf(m, ":count=%ld\n", count);
6692
6693 return 0;
6694}
6695
6696static struct ftrace_probe_ops snapshot_probe_ops = {
6697 .func = ftrace_snapshot,
6698 .print = ftrace_snapshot_print,
6699};
6700
6701static struct ftrace_probe_ops snapshot_count_probe_ops = {
6702 .func = ftrace_count_snapshot,
6703 .print = ftrace_snapshot_print,
6704};
6705
6706static int
6707ftrace_trace_snapshot_callback(struct ftrace_hash *hash,
6708 char *glob, char *cmd, char *param, int enable)
6709{
6710 struct ftrace_probe_ops *ops;
6711 void *count = (void *)-1;
6712 char *number;
6713 int ret;
6714
6715 /* hash funcs only work with set_ftrace_filter */
6716 if (!enable)
6717 return -EINVAL;
6718
6719 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
6720
6721 if (glob[0] == '!') {
6722 unregister_ftrace_function_probe_func(glob+1, ops);
6723 return 0;
6724 }
6725
6726 if (!param)
6727 goto out_reg;
6728
6729 number = strsep(¶m, ":");
6730
6731 if (!strlen(number))
6732 goto out_reg;
6733
6734 /*
6735 * We use the callback data field (which is a pointer)
6736 * as our counter.
6737 */
6738 ret = kstrtoul(number, 0, (unsigned long *)&count);
6739 if (ret)
6740 return ret;
6741
6742 out_reg:
6743 ret = register_ftrace_function_probe(glob, ops, count);
6744
6745 if (ret >= 0)
6746 alloc_snapshot(&global_trace);
6747
6748 return ret < 0 ? ret : 0;
6749}
6750
6751static struct ftrace_func_command ftrace_snapshot_cmd = {
6752 .name = "snapshot",
6753 .func = ftrace_trace_snapshot_callback,
6754};
6755
6756static __init int register_snapshot_cmd(void)
6757{
6758 return register_ftrace_command(&ftrace_snapshot_cmd);
6759}
6760#else
6761static inline __init int register_snapshot_cmd(void) { return 0; }
6762#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
6763
6764static struct dentry *tracing_get_dentry(struct trace_array *tr)
6765{
6766 if (WARN_ON(!tr->dir))
6767 return ERR_PTR(-ENODEV);
6768
6769 /* Top directory uses NULL as the parent */
6770 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
6771 return NULL;
6772
6773 /* All sub buffers have a descriptor */
6774 return tr->dir;
6775}
6776
6777static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
6778{
6779 struct dentry *d_tracer;
6780
6781 if (tr->percpu_dir)
6782 return tr->percpu_dir;
6783
6784 d_tracer = tracing_get_dentry(tr);
6785 if (IS_ERR(d_tracer))
6786 return NULL;
6787
6788 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
6789
6790 WARN_ONCE(!tr->percpu_dir,
6791 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
6792
6793 return tr->percpu_dir;
6794}
6795
6796static struct dentry *
6797trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
6798 void *data, long cpu, const struct file_operations *fops)
6799{
6800 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
6801
6802 if (ret) /* See tracing_get_cpu() */
6803 d_inode(ret)->i_cdev = (void *)(cpu + 1);
6804 return ret;
6805}
6806
6807static void
6808tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
6809{
6810 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
6811 struct dentry *d_cpu;
6812 char cpu_dir[30]; /* 30 characters should be more than enough */
6813
6814 if (!d_percpu)
6815 return;
6816
6817 snprintf(cpu_dir, 30, "cpu%ld", cpu);
6818 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
6819 if (!d_cpu) {
6820 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
6821 return;
6822 }
6823
6824 /* per cpu trace_pipe */
6825 trace_create_cpu_file("trace_pipe", 0444, d_cpu,
6826 tr, cpu, &tracing_pipe_fops);
6827
6828 /* per cpu trace */
6829 trace_create_cpu_file("trace", 0644, d_cpu,
6830 tr, cpu, &tracing_fops);
6831
6832 trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
6833 tr, cpu, &tracing_buffers_fops);
6834
6835 trace_create_cpu_file("stats", 0444, d_cpu,
6836 tr, cpu, &tracing_stats_fops);
6837
6838 trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
6839 tr, cpu, &tracing_entries_fops);
6840
6841#ifdef CONFIG_TRACER_SNAPSHOT
6842 trace_create_cpu_file("snapshot", 0644, d_cpu,
6843 tr, cpu, &snapshot_fops);
6844
6845 trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
6846 tr, cpu, &snapshot_raw_fops);
6847#endif
6848}
6849
6850#ifdef CONFIG_FTRACE_SELFTEST
6851/* Let selftest have access to static functions in this file */
6852#include "trace_selftest.c"
6853#endif
6854
6855static ssize_t
6856trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
6857 loff_t *ppos)
6858{
6859 struct trace_option_dentry *topt = filp->private_data;
6860 char *buf;
6861
6862 if (topt->flags->val & topt->opt->bit)
6863 buf = "1\n";
6864 else
6865 buf = "0\n";
6866
6867 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
6868}
6869
6870static ssize_t
6871trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
6872 loff_t *ppos)
6873{
6874 struct trace_option_dentry *topt = filp->private_data;
6875 unsigned long val;
6876 int ret;
6877
6878 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6879 if (ret)
6880 return ret;
6881
6882 if (val != 0 && val != 1)
6883 return -EINVAL;
6884
6885 if (!!(topt->flags->val & topt->opt->bit) != val) {
6886 mutex_lock(&trace_types_lock);
6887 ret = __set_tracer_option(topt->tr, topt->flags,
6888 topt->opt, !val);
6889 mutex_unlock(&trace_types_lock);
6890 if (ret)
6891 return ret;
6892 }
6893
6894 *ppos += cnt;
6895
6896 return cnt;
6897}
6898
6899
6900static const struct file_operations trace_options_fops = {
6901 .open = tracing_open_generic,
6902 .read = trace_options_read,
6903 .write = trace_options_write,
6904 .llseek = generic_file_llseek,
6905};
6906
6907/*
6908 * In order to pass in both the trace_array descriptor as well as the index
6909 * to the flag that the trace option file represents, the trace_array
6910 * has a character array of trace_flags_index[], which holds the index
6911 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
6912 * The address of this character array is passed to the flag option file
6913 * read/write callbacks.
6914 *
6915 * In order to extract both the index and the trace_array descriptor,
6916 * get_tr_index() uses the following algorithm.
6917 *
6918 * idx = *ptr;
6919 *
6920 * As the pointer itself contains the address of the index (remember
6921 * index[1] == 1).
6922 *
6923 * Then to get the trace_array descriptor, by subtracting that index
6924 * from the ptr, we get to the start of the index itself.
6925 *
6926 * ptr - idx == &index[0]
6927 *
6928 * Then a simple container_of() from that pointer gets us to the
6929 * trace_array descriptor.
6930 */
6931static void get_tr_index(void *data, struct trace_array **ptr,
6932 unsigned int *pindex)
6933{
6934 *pindex = *(unsigned char *)data;
6935
6936 *ptr = container_of(data - *pindex, struct trace_array,
6937 trace_flags_index);
6938}
6939
6940static ssize_t
6941trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
6942 loff_t *ppos)
6943{
6944 void *tr_index = filp->private_data;
6945 struct trace_array *tr;
6946 unsigned int index;
6947 char *buf;
6948
6949 get_tr_index(tr_index, &tr, &index);
6950
6951 if (tr->trace_flags & (1 << index))
6952 buf = "1\n";
6953 else
6954 buf = "0\n";
6955
6956 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
6957}
6958
6959static ssize_t
6960trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
6961 loff_t *ppos)
6962{
6963 void *tr_index = filp->private_data;
6964 struct trace_array *tr;
6965 unsigned int index;
6966 unsigned long val;
6967 int ret;
6968
6969 get_tr_index(tr_index, &tr, &index);
6970
6971 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6972 if (ret)
6973 return ret;
6974
6975 if (val != 0 && val != 1)
6976 return -EINVAL;
6977
6978 mutex_lock(&trace_types_lock);
6979 ret = set_tracer_flag(tr, 1 << index, val);
6980 mutex_unlock(&trace_types_lock);
6981
6982 if (ret < 0)
6983 return ret;
6984
6985 *ppos += cnt;
6986
6987 return cnt;
6988}
6989
6990static const struct file_operations trace_options_core_fops = {
6991 .open = tracing_open_generic,
6992 .read = trace_options_core_read,
6993 .write = trace_options_core_write,
6994 .llseek = generic_file_llseek,
6995};
6996
6997struct dentry *trace_create_file(const char *name,
6998 umode_t mode,
6999 struct dentry *parent,
7000 void *data,
7001 const struct file_operations *fops)
7002{
7003 struct dentry *ret;
7004
7005 ret = tracefs_create_file(name, mode, parent, data, fops);
7006 if (!ret)
7007 pr_warn("Could not create tracefs '%s' entry\n", name);
7008
7009 return ret;
7010}
7011
7012
7013static struct dentry *trace_options_init_dentry(struct trace_array *tr)
7014{
7015 struct dentry *d_tracer;
7016
7017 if (tr->options)
7018 return tr->options;
7019
7020 d_tracer = tracing_get_dentry(tr);
7021 if (IS_ERR(d_tracer))
7022 return NULL;
7023
7024 tr->options = tracefs_create_dir("options", d_tracer);
7025 if (!tr->options) {
7026 pr_warn("Could not create tracefs directory 'options'\n");
7027 return NULL;
7028 }
7029
7030 return tr->options;
7031}
7032
7033static void
7034create_trace_option_file(struct trace_array *tr,
7035 struct trace_option_dentry *topt,
7036 struct tracer_flags *flags,
7037 struct tracer_opt *opt)
7038{
7039 struct dentry *t_options;
7040
7041 t_options = trace_options_init_dentry(tr);
7042 if (!t_options)
7043 return;
7044
7045 topt->flags = flags;
7046 topt->opt = opt;
7047 topt->tr = tr;
7048
7049 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
7050 &trace_options_fops);
7051
7052}
7053
7054static void
7055create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
7056{
7057 struct trace_option_dentry *topts;
7058 struct trace_options *tr_topts;
7059 struct tracer_flags *flags;
7060 struct tracer_opt *opts;
7061 int cnt;
7062 int i;
7063
7064 if (!tracer)
7065 return;
7066
7067 flags = tracer->flags;
7068
7069 if (!flags || !flags->opts)
7070 return;
7071
7072 /*
7073 * If this is an instance, only create flags for tracers
7074 * the instance may have.
7075 */
7076 if (!trace_ok_for_array(tracer, tr))
7077 return;
7078
7079 for (i = 0; i < tr->nr_topts; i++) {
7080 /* Make sure there's no duplicate flags. */
7081 if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
7082 return;
7083 }
7084
7085 opts = flags->opts;
7086
7087 for (cnt = 0; opts[cnt].name; cnt++)
7088 ;
7089
7090 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
7091 if (!topts)
7092 return;
7093
7094 tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
7095 GFP_KERNEL);
7096 if (!tr_topts) {
7097 kfree(topts);
7098 return;
7099 }
7100
7101 tr->topts = tr_topts;
7102 tr->topts[tr->nr_topts].tracer = tracer;
7103 tr->topts[tr->nr_topts].topts = topts;
7104 tr->nr_topts++;
7105
7106 for (cnt = 0; opts[cnt].name; cnt++) {
7107 create_trace_option_file(tr, &topts[cnt], flags,
7108 &opts[cnt]);
7109 WARN_ONCE(topts[cnt].entry == NULL,
7110 "Failed to create trace option: %s",
7111 opts[cnt].name);
7112 }
7113}
7114
7115static struct dentry *
7116create_trace_option_core_file(struct trace_array *tr,
7117 const char *option, long index)
7118{
7119 struct dentry *t_options;
7120
7121 t_options = trace_options_init_dentry(tr);
7122 if (!t_options)
7123 return NULL;
7124
7125 return trace_create_file(option, 0644, t_options,
7126 (void *)&tr->trace_flags_index[index],
7127 &trace_options_core_fops);
7128}
7129
7130static void create_trace_options_dir(struct trace_array *tr)
7131{
7132 struct dentry *t_options;
7133 bool top_level = tr == &global_trace;
7134 int i;
7135
7136 t_options = trace_options_init_dentry(tr);
7137 if (!t_options)
7138 return;
7139
7140 for (i = 0; trace_options[i]; i++) {
7141 if (top_level ||
7142 !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
7143 create_trace_option_core_file(tr, trace_options[i], i);
7144 }
7145}
7146
7147static ssize_t
7148rb_simple_read(struct file *filp, char __user *ubuf,
7149 size_t cnt, loff_t *ppos)
7150{
7151 struct trace_array *tr = filp->private_data;
7152 char buf[64];
7153 int r;
7154
7155 r = tracer_tracing_is_on(tr);
7156 r = sprintf(buf, "%d\n", r);
7157
7158 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7159}
7160
7161static ssize_t
7162rb_simple_write(struct file *filp, const char __user *ubuf,
7163 size_t cnt, loff_t *ppos)
7164{
7165 struct trace_array *tr = filp->private_data;
7166 struct ring_buffer *buffer = tr->trace_buffer.buffer;
7167 unsigned long val;
7168 int ret;
7169
7170 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7171 if (ret)
7172 return ret;
7173
7174 if (buffer) {
7175 mutex_lock(&trace_types_lock);
7176 if (val) {
7177 tracer_tracing_on(tr);
7178 if (tr->current_trace->start)
7179 tr->current_trace->start(tr);
7180 } else {
7181 tracer_tracing_off(tr);
7182 if (tr->current_trace->stop)
7183 tr->current_trace->stop(tr);
7184 }
7185 mutex_unlock(&trace_types_lock);
7186 }
7187
7188 (*ppos)++;
7189
7190 return cnt;
7191}
7192
7193static const struct file_operations rb_simple_fops = {
7194 .open = tracing_open_generic_tr,
7195 .read = rb_simple_read,
7196 .write = rb_simple_write,
7197 .release = tracing_release_generic_tr,
7198 .llseek = default_llseek,
7199};
7200
7201struct dentry *trace_instance_dir;
7202
7203static void
7204init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
7205
7206static int
7207allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
7208{
7209 enum ring_buffer_flags rb_flags;
7210
7211 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
7212
7213 buf->tr = tr;
7214
7215 buf->buffer = ring_buffer_alloc(size, rb_flags);
7216 if (!buf->buffer)
7217 return -ENOMEM;
7218
7219 buf->data = alloc_percpu(struct trace_array_cpu);
7220 if (!buf->data) {
7221 ring_buffer_free(buf->buffer);
7222 return -ENOMEM;
7223 }
7224
7225 /* Allocate the first page for all buffers */
7226 set_buffer_entries(&tr->trace_buffer,
7227 ring_buffer_size(tr->trace_buffer.buffer, 0));
7228
7229 return 0;
7230}
7231
7232static int allocate_trace_buffers(struct trace_array *tr, int size)
7233{
7234 int ret;
7235
7236 ret = allocate_trace_buffer(tr, &tr->trace_buffer, size);
7237 if (ret)
7238 return ret;
7239
7240#ifdef CONFIG_TRACER_MAX_TRACE
7241 ret = allocate_trace_buffer(tr, &tr->max_buffer,
7242 allocate_snapshot ? size : 1);
7243 if (WARN_ON(ret)) {
7244 ring_buffer_free(tr->trace_buffer.buffer);
7245 free_percpu(tr->trace_buffer.data);
7246 return -ENOMEM;
7247 }
7248 tr->allocated_snapshot = allocate_snapshot;
7249
7250 /*
7251 * Only the top level trace array gets its snapshot allocated
7252 * from the kernel command line.
7253 */
7254 allocate_snapshot = false;
7255#endif
7256 return 0;
7257}
7258
7259static void free_trace_buffer(struct trace_buffer *buf)
7260{
7261 if (buf->buffer) {
7262 ring_buffer_free(buf->buffer);
7263 buf->buffer = NULL;
7264 free_percpu(buf->data);
7265 buf->data = NULL;
7266 }
7267}
7268
7269static void free_trace_buffers(struct trace_array *tr)
7270{
7271 if (!tr)
7272 return;
7273
7274 free_trace_buffer(&tr->trace_buffer);
7275
7276#ifdef CONFIG_TRACER_MAX_TRACE
7277 free_trace_buffer(&tr->max_buffer);
7278#endif
7279}
7280
7281static void init_trace_flags_index(struct trace_array *tr)
7282{
7283 int i;
7284
7285 /* Used by the trace options files */
7286 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
7287 tr->trace_flags_index[i] = i;
7288}
7289
7290static void __update_tracer_options(struct trace_array *tr)
7291{
7292 struct tracer *t;
7293
7294 for (t = trace_types; t; t = t->next)
7295 add_tracer_options(tr, t);
7296}
7297
7298static void update_tracer_options(struct trace_array *tr)
7299{
7300 mutex_lock(&trace_types_lock);
7301 __update_tracer_options(tr);
7302 mutex_unlock(&trace_types_lock);
7303}
7304
7305static int instance_mkdir(const char *name)
7306{
7307 struct trace_array *tr;
7308 int ret;
7309
7310 mutex_lock(&trace_types_lock);
7311
7312 ret = -EEXIST;
7313 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7314 if (tr->name && strcmp(tr->name, name) == 0)
7315 goto out_unlock;
7316 }
7317
7318 ret = -ENOMEM;
7319 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
7320 if (!tr)
7321 goto out_unlock;
7322
7323 tr->name = kstrdup(name, GFP_KERNEL);
7324 if (!tr->name)
7325 goto out_free_tr;
7326
7327 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
7328 goto out_free_tr;
7329
7330 tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
7331
7332 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
7333
7334 raw_spin_lock_init(&tr->start_lock);
7335
7336 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
7337
7338 tr->current_trace = &nop_trace;
7339
7340 INIT_LIST_HEAD(&tr->systems);
7341 INIT_LIST_HEAD(&tr->events);
7342
7343 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
7344 goto out_free_tr;
7345
7346 tr->dir = tracefs_create_dir(name, trace_instance_dir);
7347 if (!tr->dir)
7348 goto out_free_tr;
7349
7350 ret = event_trace_add_tracer(tr->dir, tr);
7351 if (ret) {
7352 tracefs_remove_recursive(tr->dir);
7353 goto out_free_tr;
7354 }
7355
7356 init_tracer_tracefs(tr, tr->dir);
7357 init_trace_flags_index(tr);
7358 __update_tracer_options(tr);
7359
7360 list_add(&tr->list, &ftrace_trace_arrays);
7361
7362 mutex_unlock(&trace_types_lock);
7363
7364 return 0;
7365
7366 out_free_tr:
7367 free_trace_buffers(tr);
7368 free_cpumask_var(tr->tracing_cpumask);
7369 kfree(tr->name);
7370 kfree(tr);
7371
7372 out_unlock:
7373 mutex_unlock(&trace_types_lock);
7374
7375 return ret;
7376
7377}
7378
7379static int instance_rmdir(const char *name)
7380{
7381 struct trace_array *tr;
7382 int found = 0;
7383 int ret;
7384 int i;
7385
7386 mutex_lock(&trace_types_lock);
7387
7388 ret = -ENODEV;
7389 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7390 if (tr->name && strcmp(tr->name, name) == 0) {
7391 found = 1;
7392 break;
7393 }
7394 }
7395 if (!found)
7396 goto out_unlock;
7397
7398 ret = -EBUSY;
7399 if (tr->ref || (tr->current_trace && tr->current_trace->ref))
7400 goto out_unlock;
7401
7402 list_del(&tr->list);
7403
7404 /* Disable all the flags that were enabled coming in */
7405 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
7406 if ((1 << i) & ZEROED_TRACE_FLAGS)
7407 set_tracer_flag(tr, 1 << i, 0);
7408 }
7409
7410 tracing_set_nop(tr);
7411 event_trace_del_tracer(tr);
7412 ftrace_destroy_function_files(tr);
7413 tracefs_remove_recursive(tr->dir);
7414 free_trace_buffers(tr);
7415
7416 for (i = 0; i < tr->nr_topts; i++) {
7417 kfree(tr->topts[i].topts);
7418 }
7419 kfree(tr->topts);
7420
7421 kfree(tr->name);
7422 kfree(tr);
7423
7424 ret = 0;
7425
7426 out_unlock:
7427 mutex_unlock(&trace_types_lock);
7428
7429 return ret;
7430}
7431
7432static __init void create_trace_instances(struct dentry *d_tracer)
7433{
7434 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
7435 instance_mkdir,
7436 instance_rmdir);
7437 if (WARN_ON(!trace_instance_dir))
7438 return;
7439}
7440
7441static void
7442init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7443{
7444 int cpu;
7445
7446 trace_create_file("available_tracers", 0444, d_tracer,
7447 tr, &show_traces_fops);
7448
7449 trace_create_file("current_tracer", 0644, d_tracer,
7450 tr, &set_tracer_fops);
7451
7452 trace_create_file("tracing_cpumask", 0644, d_tracer,
7453 tr, &tracing_cpumask_fops);
7454
7455 trace_create_file("trace_options", 0644, d_tracer,
7456 tr, &tracing_iter_fops);
7457
7458 trace_create_file("trace", 0644, d_tracer,
7459 tr, &tracing_fops);
7460
7461 trace_create_file("trace_pipe", 0444, d_tracer,
7462 tr, &tracing_pipe_fops);
7463
7464 trace_create_file("buffer_size_kb", 0644, d_tracer,
7465 tr, &tracing_entries_fops);
7466
7467 trace_create_file("buffer_total_size_kb", 0444, d_tracer,
7468 tr, &tracing_total_entries_fops);
7469
7470 trace_create_file("free_buffer", 0200, d_tracer,
7471 tr, &tracing_free_buffer_fops);
7472
7473 trace_create_file("trace_marker", 0220, d_tracer,
7474 tr, &tracing_mark_fops);
7475
7476 trace_create_file("trace_marker_raw", 0220, d_tracer,
7477 tr, &tracing_mark_raw_fops);
7478
7479 trace_create_file("trace_clock", 0644, d_tracer, tr,
7480 &trace_clock_fops);
7481
7482 trace_create_file("tracing_on", 0644, d_tracer,
7483 tr, &rb_simple_fops);
7484
7485 create_trace_options_dir(tr);
7486
7487#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
7488 trace_create_file("tracing_max_latency", 0644, d_tracer,
7489 &tr->max_latency, &tracing_max_lat_fops);
7490#endif
7491
7492 if (ftrace_create_function_files(tr, d_tracer))
7493 WARN(1, "Could not allocate function filter files");
7494
7495#ifdef CONFIG_TRACER_SNAPSHOT
7496 trace_create_file("snapshot", 0644, d_tracer,
7497 tr, &snapshot_fops);
7498#endif
7499
7500 for_each_tracing_cpu(cpu)
7501 tracing_init_tracefs_percpu(tr, cpu);
7502
7503 ftrace_init_tracefs(tr, d_tracer);
7504}
7505
7506static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
7507{
7508 struct vfsmount *mnt;
7509 struct file_system_type *type;
7510
7511 /*
7512 * To maintain backward compatibility for tools that mount
7513 * debugfs to get to the tracing facility, tracefs is automatically
7514 * mounted to the debugfs/tracing directory.
7515 */
7516 type = get_fs_type("tracefs");
7517 if (!type)
7518 return NULL;
7519 mnt = vfs_submount(mntpt, type, "tracefs", NULL);
7520 put_filesystem(type);
7521 if (IS_ERR(mnt))
7522 return NULL;
7523 mntget(mnt);
7524
7525 return mnt;
7526}
7527
7528/**
7529 * tracing_init_dentry - initialize top level trace array
7530 *
7531 * This is called when creating files or directories in the tracing
7532 * directory. It is called via fs_initcall() by any of the boot up code
7533 * and expects to return the dentry of the top level tracing directory.
7534 */
7535struct dentry *tracing_init_dentry(void)
7536{
7537 struct trace_array *tr = &global_trace;
7538
7539 /* The top level trace array uses NULL as parent */
7540 if (tr->dir)
7541 return NULL;
7542
7543 if (WARN_ON(!tracefs_initialized()) ||
7544 (IS_ENABLED(CONFIG_DEBUG_FS) &&
7545 WARN_ON(!debugfs_initialized())))
7546 return ERR_PTR(-ENODEV);
7547
7548 /*
7549 * As there may still be users that expect the tracing
7550 * files to exist in debugfs/tracing, we must automount
7551 * the tracefs file system there, so older tools still
7552 * work with the newer kerenl.
7553 */
7554 tr->dir = debugfs_create_automount("tracing", NULL,
7555 trace_automount, NULL);
7556 if (!tr->dir) {
7557 pr_warn_once("Could not create debugfs directory 'tracing'\n");
7558 return ERR_PTR(-ENOMEM);
7559 }
7560
7561 return NULL;
7562}
7563
7564extern struct trace_enum_map *__start_ftrace_enum_maps[];
7565extern struct trace_enum_map *__stop_ftrace_enum_maps[];
7566
7567static void __init trace_enum_init(void)
7568{
7569 int len;
7570
7571 len = __stop_ftrace_enum_maps - __start_ftrace_enum_maps;
7572 trace_insert_enum_map(NULL, __start_ftrace_enum_maps, len);
7573}
7574
7575#ifdef CONFIG_MODULES
7576static void trace_module_add_enums(struct module *mod)
7577{
7578 if (!mod->num_trace_enums)
7579 return;
7580
7581 /*
7582 * Modules with bad taint do not have events created, do
7583 * not bother with enums either.
7584 */
7585 if (trace_module_has_bad_taint(mod))
7586 return;
7587
7588 trace_insert_enum_map(mod, mod->trace_enums, mod->num_trace_enums);
7589}
7590
7591#ifdef CONFIG_TRACE_ENUM_MAP_FILE
7592static void trace_module_remove_enums(struct module *mod)
7593{
7594 union trace_enum_map_item *map;
7595 union trace_enum_map_item **last = &trace_enum_maps;
7596
7597 if (!mod->num_trace_enums)
7598 return;
7599
7600 mutex_lock(&trace_enum_mutex);
7601
7602 map = trace_enum_maps;
7603
7604 while (map) {
7605 if (map->head.mod == mod)
7606 break;
7607 map = trace_enum_jmp_to_tail(map);
7608 last = &map->tail.next;
7609 map = map->tail.next;
7610 }
7611 if (!map)
7612 goto out;
7613
7614 *last = trace_enum_jmp_to_tail(map)->tail.next;
7615 kfree(map);
7616 out:
7617 mutex_unlock(&trace_enum_mutex);
7618}
7619#else
7620static inline void trace_module_remove_enums(struct module *mod) { }
7621#endif /* CONFIG_TRACE_ENUM_MAP_FILE */
7622
7623static int trace_module_notify(struct notifier_block *self,
7624 unsigned long val, void *data)
7625{
7626 struct module *mod = data;
7627
7628 switch (val) {
7629 case MODULE_STATE_COMING:
7630 trace_module_add_enums(mod);
7631 break;
7632 case MODULE_STATE_GOING:
7633 trace_module_remove_enums(mod);
7634 break;
7635 }
7636
7637 return 0;
7638}
7639
7640static struct notifier_block trace_module_nb = {
7641 .notifier_call = trace_module_notify,
7642 .priority = 0,
7643};
7644#endif /* CONFIG_MODULES */
7645
7646static __init int tracer_init_tracefs(void)
7647{
7648 struct dentry *d_tracer;
7649
7650 trace_access_lock_init();
7651
7652 d_tracer = tracing_init_dentry();
7653 if (IS_ERR(d_tracer))
7654 return 0;
7655
7656 init_tracer_tracefs(&global_trace, d_tracer);
7657 ftrace_init_tracefs_toplevel(&global_trace, d_tracer);
7658
7659 trace_create_file("tracing_thresh", 0644, d_tracer,
7660 &global_trace, &tracing_thresh_fops);
7661
7662 trace_create_file("README", 0444, d_tracer,
7663 NULL, &tracing_readme_fops);
7664
7665 trace_create_file("saved_cmdlines", 0444, d_tracer,
7666 NULL, &tracing_saved_cmdlines_fops);
7667
7668 trace_create_file("saved_cmdlines_size", 0644, d_tracer,
7669 NULL, &tracing_saved_cmdlines_size_fops);
7670
7671 trace_enum_init();
7672
7673 trace_create_enum_file(d_tracer);
7674
7675#ifdef CONFIG_MODULES
7676 register_module_notifier(&trace_module_nb);
7677#endif
7678
7679#ifdef CONFIG_DYNAMIC_FTRACE
7680 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
7681 &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
7682#endif
7683
7684 create_trace_instances(d_tracer);
7685
7686 update_tracer_options(&global_trace);
7687
7688 return 0;
7689}
7690
7691static int trace_panic_handler(struct notifier_block *this,
7692 unsigned long event, void *unused)
7693{
7694 if (ftrace_dump_on_oops)
7695 ftrace_dump(ftrace_dump_on_oops);
7696 return NOTIFY_OK;
7697}
7698
7699static struct notifier_block trace_panic_notifier = {
7700 .notifier_call = trace_panic_handler,
7701 .next = NULL,
7702 .priority = 150 /* priority: INT_MAX >= x >= 0 */
7703};
7704
7705static int trace_die_handler(struct notifier_block *self,
7706 unsigned long val,
7707 void *data)
7708{
7709 switch (val) {
7710 case DIE_OOPS:
7711 if (ftrace_dump_on_oops)
7712 ftrace_dump(ftrace_dump_on_oops);
7713 break;
7714 default:
7715 break;
7716 }
7717 return NOTIFY_OK;
7718}
7719
7720static struct notifier_block trace_die_notifier = {
7721 .notifier_call = trace_die_handler,
7722 .priority = 200
7723};
7724
7725/*
7726 * printk is set to max of 1024, we really don't need it that big.
7727 * Nothing should be printing 1000 characters anyway.
7728 */
7729#define TRACE_MAX_PRINT 1000
7730
7731/*
7732 * Define here KERN_TRACE so that we have one place to modify
7733 * it if we decide to change what log level the ftrace dump
7734 * should be at.
7735 */
7736#define KERN_TRACE KERN_EMERG
7737
7738void
7739trace_printk_seq(struct trace_seq *s)
7740{
7741 /* Probably should print a warning here. */
7742 if (s->seq.len >= TRACE_MAX_PRINT)
7743 s->seq.len = TRACE_MAX_PRINT;
7744
7745 /*
7746 * More paranoid code. Although the buffer size is set to
7747 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
7748 * an extra layer of protection.
7749 */
7750 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
7751 s->seq.len = s->seq.size - 1;
7752
7753 /* should be zero ended, but we are paranoid. */
7754 s->buffer[s->seq.len] = 0;
7755
7756 printk(KERN_TRACE "%s", s->buffer);
7757
7758 trace_seq_init(s);
7759}
7760
7761void trace_init_global_iter(struct trace_iterator *iter)
7762{
7763 iter->tr = &global_trace;
7764 iter->trace = iter->tr->current_trace;
7765 iter->cpu_file = RING_BUFFER_ALL_CPUS;
7766 iter->trace_buffer = &global_trace.trace_buffer;
7767
7768 if (iter->trace && iter->trace->open)
7769 iter->trace->open(iter);
7770
7771 /* Annotate start of buffers if we had overruns */
7772 if (ring_buffer_overruns(iter->trace_buffer->buffer))
7773 iter->iter_flags |= TRACE_FILE_ANNOTATE;
7774
7775 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
7776 if (trace_clocks[iter->tr->clock_id].in_ns)
7777 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
7778}
7779
7780void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
7781{
7782 /* use static because iter can be a bit big for the stack */
7783 static struct trace_iterator iter;
7784 static atomic_t dump_running;
7785 struct trace_array *tr = &global_trace;
7786 unsigned int old_userobj;
7787 unsigned long flags;
7788 int cnt = 0, cpu;
7789
7790 /* Only allow one dump user at a time. */
7791 if (atomic_inc_return(&dump_running) != 1) {
7792 atomic_dec(&dump_running);
7793 return;
7794 }
7795
7796 /*
7797 * Always turn off tracing when we dump.
7798 * We don't need to show trace output of what happens
7799 * between multiple crashes.
7800 *
7801 * If the user does a sysrq-z, then they can re-enable
7802 * tracing with echo 1 > tracing_on.
7803 */
7804 tracing_off();
7805
7806 local_irq_save(flags);
7807
7808 /* Simulate the iterator */
7809 trace_init_global_iter(&iter);
7810
7811 for_each_tracing_cpu(cpu) {
7812 atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
7813 }
7814
7815 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
7816
7817 /* don't look at user memory in panic mode */
7818 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
7819
7820 switch (oops_dump_mode) {
7821 case DUMP_ALL:
7822 iter.cpu_file = RING_BUFFER_ALL_CPUS;
7823 break;
7824 case DUMP_ORIG:
7825 iter.cpu_file = raw_smp_processor_id();
7826 break;
7827 case DUMP_NONE:
7828 goto out_enable;
7829 default:
7830 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
7831 iter.cpu_file = RING_BUFFER_ALL_CPUS;
7832 }
7833
7834 printk(KERN_TRACE "Dumping ftrace buffer:\n");
7835
7836 /* Did function tracer already get disabled? */
7837 if (ftrace_is_dead()) {
7838 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
7839 printk("# MAY BE MISSING FUNCTION EVENTS\n");
7840 }
7841
7842 /*
7843 * We need to stop all tracing on all CPUS to read the
7844 * the next buffer. This is a bit expensive, but is
7845 * not done often. We fill all what we can read,
7846 * and then release the locks again.
7847 */
7848
7849 while (!trace_empty(&iter)) {
7850
7851 if (!cnt)
7852 printk(KERN_TRACE "---------------------------------\n");
7853
7854 cnt++;
7855
7856 /* reset all but tr, trace, and overruns */
7857 memset(&iter.seq, 0,
7858 sizeof(struct trace_iterator) -
7859 offsetof(struct trace_iterator, seq));
7860 iter.iter_flags |= TRACE_FILE_LAT_FMT;
7861 iter.pos = -1;
7862
7863 if (trace_find_next_entry_inc(&iter) != NULL) {
7864 int ret;
7865
7866 ret = print_trace_line(&iter);
7867 if (ret != TRACE_TYPE_NO_CONSUME)
7868 trace_consume(&iter);
7869 }
7870 touch_nmi_watchdog();
7871
7872 trace_printk_seq(&iter.seq);
7873 }
7874
7875 if (!cnt)
7876 printk(KERN_TRACE " (ftrace buffer empty)\n");
7877 else
7878 printk(KERN_TRACE "---------------------------------\n");
7879
7880 out_enable:
7881 tr->trace_flags |= old_userobj;
7882
7883 for_each_tracing_cpu(cpu) {
7884 atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
7885 }
7886 atomic_dec(&dump_running);
7887 local_irq_restore(flags);
7888}
7889EXPORT_SYMBOL_GPL(ftrace_dump);
7890
7891__init static int tracer_alloc_buffers(void)
7892{
7893 int ring_buf_size;
7894 int ret = -ENOMEM;
7895
7896 /*
7897 * Make sure we don't accidently add more trace options
7898 * than we have bits for.
7899 */
7900 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
7901
7902 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
7903 goto out;
7904
7905 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
7906 goto out_free_buffer_mask;
7907
7908 /* Only allocate trace_printk buffers if a trace_printk exists */
7909 if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
7910 /* Must be called before global_trace.buffer is allocated */
7911 trace_printk_init_buffers();
7912
7913 /* To save memory, keep the ring buffer size to its minimum */
7914 if (ring_buffer_expanded)
7915 ring_buf_size = trace_buf_size;
7916 else
7917 ring_buf_size = 1;
7918
7919 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
7920 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
7921
7922 raw_spin_lock_init(&global_trace.start_lock);
7923
7924 /*
7925 * The prepare callbacks allocates some memory for the ring buffer. We
7926 * don't free the buffer if the if the CPU goes down. If we were to free
7927 * the buffer, then the user would lose any trace that was in the
7928 * buffer. The memory will be removed once the "instance" is removed.
7929 */
7930 ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
7931 "trace/RB:preapre", trace_rb_cpu_prepare,
7932 NULL);
7933 if (ret < 0)
7934 goto out_free_cpumask;
7935 /* Used for event triggers */
7936 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
7937 if (!temp_buffer)
7938 goto out_rm_hp_state;
7939
7940 if (trace_create_savedcmd() < 0)
7941 goto out_free_temp_buffer;
7942
7943 /* TODO: make the number of buffers hot pluggable with CPUS */
7944 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
7945 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
7946 WARN_ON(1);
7947 goto out_free_savedcmd;
7948 }
7949
7950 if (global_trace.buffer_disabled)
7951 tracing_off();
7952
7953 if (trace_boot_clock) {
7954 ret = tracing_set_clock(&global_trace, trace_boot_clock);
7955 if (ret < 0)
7956 pr_warn("Trace clock %s not defined, going back to default\n",
7957 trace_boot_clock);
7958 }
7959
7960 /*
7961 * register_tracer() might reference current_trace, so it
7962 * needs to be set before we register anything. This is
7963 * just a bootstrap of current_trace anyway.
7964 */
7965 global_trace.current_trace = &nop_trace;
7966
7967 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
7968
7969 ftrace_init_global_array_ops(&global_trace);
7970
7971 init_trace_flags_index(&global_trace);
7972
7973 register_tracer(&nop_trace);
7974
7975 /* All seems OK, enable tracing */
7976 tracing_disabled = 0;
7977
7978 atomic_notifier_chain_register(&panic_notifier_list,
7979 &trace_panic_notifier);
7980
7981 register_die_notifier(&trace_die_notifier);
7982
7983 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
7984
7985 INIT_LIST_HEAD(&global_trace.systems);
7986 INIT_LIST_HEAD(&global_trace.events);
7987 list_add(&global_trace.list, &ftrace_trace_arrays);
7988
7989 apply_trace_boot_options();
7990
7991 register_snapshot_cmd();
7992
7993 return 0;
7994
7995out_free_savedcmd:
7996 free_saved_cmdlines_buffer(savedcmd);
7997out_free_temp_buffer:
7998 ring_buffer_free(temp_buffer);
7999out_rm_hp_state:
8000 cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
8001out_free_cpumask:
8002 free_cpumask_var(global_trace.tracing_cpumask);
8003out_free_buffer_mask:
8004 free_cpumask_var(tracing_buffer_mask);
8005out:
8006 return ret;
8007}
8008
8009void __init trace_init(void)
8010{
8011 if (tracepoint_printk) {
8012 tracepoint_print_iter =
8013 kmalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
8014 if (WARN_ON(!tracepoint_print_iter))
8015 tracepoint_printk = 0;
8016 else
8017 static_key_enable(&tracepoint_printk_key.key);
8018 }
8019 tracer_alloc_buffers();
8020 trace_event_init();
8021}
8022
8023__init static int clear_boot_tracer(void)
8024{
8025 /*
8026 * The default tracer at boot buffer is an init section.
8027 * This function is called in lateinit. If we did not
8028 * find the boot tracer, then clear it out, to prevent
8029 * later registration from accessing the buffer that is
8030 * about to be freed.
8031 */
8032 if (!default_bootup_tracer)
8033 return 0;
8034
8035 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
8036 default_bootup_tracer);
8037 default_bootup_tracer = NULL;
8038
8039 return 0;
8040}
8041
8042fs_initcall(tracer_init_tracefs);
8043late_initcall(clear_boot_tracer);