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1/*
2 * event tracer
3 *
4 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
5 *
6 * - Added format output of fields of the trace point.
7 * This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
8 *
9 */
10
11#define pr_fmt(fmt) fmt
12
13#include <linux/workqueue.h>
14#include <linux/spinlock.h>
15#include <linux/kthread.h>
16#include <linux/tracefs.h>
17#include <linux/uaccess.h>
18#include <linux/bsearch.h>
19#include <linux/module.h>
20#include <linux/ctype.h>
21#include <linux/sort.h>
22#include <linux/slab.h>
23#include <linux/delay.h>
24
25#include <trace/events/sched.h>
26
27#include <asm/setup.h>
28
29#include "trace_output.h"
30
31#undef TRACE_SYSTEM
32#define TRACE_SYSTEM "TRACE_SYSTEM"
33
34DEFINE_MUTEX(event_mutex);
35
36LIST_HEAD(ftrace_events);
37static LIST_HEAD(ftrace_generic_fields);
38static LIST_HEAD(ftrace_common_fields);
39
40#define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
41
42static struct kmem_cache *field_cachep;
43static struct kmem_cache *file_cachep;
44
45static inline int system_refcount(struct event_subsystem *system)
46{
47 return system->ref_count;
48}
49
50static int system_refcount_inc(struct event_subsystem *system)
51{
52 return system->ref_count++;
53}
54
55static int system_refcount_dec(struct event_subsystem *system)
56{
57 return --system->ref_count;
58}
59
60/* Double loops, do not use break, only goto's work */
61#define do_for_each_event_file(tr, file) \
62 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
63 list_for_each_entry(file, &tr->events, list)
64
65#define do_for_each_event_file_safe(tr, file) \
66 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
67 struct trace_event_file *___n; \
68 list_for_each_entry_safe(file, ___n, &tr->events, list)
69
70#define while_for_each_event_file() \
71 }
72
73static struct list_head *
74trace_get_fields(struct trace_event_call *event_call)
75{
76 if (!event_call->class->get_fields)
77 return &event_call->class->fields;
78 return event_call->class->get_fields(event_call);
79}
80
81static struct ftrace_event_field *
82__find_event_field(struct list_head *head, char *name)
83{
84 struct ftrace_event_field *field;
85
86 list_for_each_entry(field, head, link) {
87 if (!strcmp(field->name, name))
88 return field;
89 }
90
91 return NULL;
92}
93
94struct ftrace_event_field *
95trace_find_event_field(struct trace_event_call *call, char *name)
96{
97 struct ftrace_event_field *field;
98 struct list_head *head;
99
100 head = trace_get_fields(call);
101 field = __find_event_field(head, name);
102 if (field)
103 return field;
104
105 field = __find_event_field(&ftrace_generic_fields, name);
106 if (field)
107 return field;
108
109 return __find_event_field(&ftrace_common_fields, name);
110}
111
112static int __trace_define_field(struct list_head *head, const char *type,
113 const char *name, int offset, int size,
114 int is_signed, int filter_type)
115{
116 struct ftrace_event_field *field;
117
118 field = kmem_cache_alloc(field_cachep, GFP_TRACE);
119 if (!field)
120 return -ENOMEM;
121
122 field->name = name;
123 field->type = type;
124
125 if (filter_type == FILTER_OTHER)
126 field->filter_type = filter_assign_type(type);
127 else
128 field->filter_type = filter_type;
129
130 field->offset = offset;
131 field->size = size;
132 field->is_signed = is_signed;
133
134 list_add(&field->link, head);
135
136 return 0;
137}
138
139int trace_define_field(struct trace_event_call *call, const char *type,
140 const char *name, int offset, int size, int is_signed,
141 int filter_type)
142{
143 struct list_head *head;
144
145 if (WARN_ON(!call->class))
146 return 0;
147
148 head = trace_get_fields(call);
149 return __trace_define_field(head, type, name, offset, size,
150 is_signed, filter_type);
151}
152EXPORT_SYMBOL_GPL(trace_define_field);
153
154#define __generic_field(type, item, filter_type) \
155 ret = __trace_define_field(&ftrace_generic_fields, #type, \
156 #item, 0, 0, is_signed_type(type), \
157 filter_type); \
158 if (ret) \
159 return ret;
160
161#define __common_field(type, item) \
162 ret = __trace_define_field(&ftrace_common_fields, #type, \
163 "common_" #item, \
164 offsetof(typeof(ent), item), \
165 sizeof(ent.item), \
166 is_signed_type(type), FILTER_OTHER); \
167 if (ret) \
168 return ret;
169
170static int trace_define_generic_fields(void)
171{
172 int ret;
173
174 __generic_field(int, CPU, FILTER_CPU);
175 __generic_field(int, cpu, FILTER_CPU);
176 __generic_field(char *, COMM, FILTER_COMM);
177 __generic_field(char *, comm, FILTER_COMM);
178
179 return ret;
180}
181
182static int trace_define_common_fields(void)
183{
184 int ret;
185 struct trace_entry ent;
186
187 __common_field(unsigned short, type);
188 __common_field(unsigned char, flags);
189 __common_field(unsigned char, preempt_count);
190 __common_field(int, pid);
191
192 return ret;
193}
194
195static void trace_destroy_fields(struct trace_event_call *call)
196{
197 struct ftrace_event_field *field, *next;
198 struct list_head *head;
199
200 head = trace_get_fields(call);
201 list_for_each_entry_safe(field, next, head, link) {
202 list_del(&field->link);
203 kmem_cache_free(field_cachep, field);
204 }
205}
206
207int trace_event_raw_init(struct trace_event_call *call)
208{
209 int id;
210
211 id = register_trace_event(&call->event);
212 if (!id)
213 return -ENODEV;
214
215 return 0;
216}
217EXPORT_SYMBOL_GPL(trace_event_raw_init);
218
219bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
220{
221 struct trace_array *tr = trace_file->tr;
222 struct trace_array_cpu *data;
223 struct trace_pid_list *pid_list;
224
225 pid_list = rcu_dereference_sched(tr->filtered_pids);
226 if (!pid_list)
227 return false;
228
229 data = this_cpu_ptr(tr->trace_buffer.data);
230
231 return data->ignore_pid;
232}
233EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
234
235void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
236 struct trace_event_file *trace_file,
237 unsigned long len)
238{
239 struct trace_event_call *event_call = trace_file->event_call;
240
241 if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
242 trace_event_ignore_this_pid(trace_file))
243 return NULL;
244
245 local_save_flags(fbuffer->flags);
246 fbuffer->pc = preempt_count();
247 fbuffer->trace_file = trace_file;
248
249 fbuffer->event =
250 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
251 event_call->event.type, len,
252 fbuffer->flags, fbuffer->pc);
253 if (!fbuffer->event)
254 return NULL;
255
256 fbuffer->entry = ring_buffer_event_data(fbuffer->event);
257 return fbuffer->entry;
258}
259EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
260
261static DEFINE_SPINLOCK(tracepoint_iter_lock);
262
263static void output_printk(struct trace_event_buffer *fbuffer)
264{
265 struct trace_event_call *event_call;
266 struct trace_event *event;
267 unsigned long flags;
268 struct trace_iterator *iter = tracepoint_print_iter;
269
270 if (!iter)
271 return;
272
273 event_call = fbuffer->trace_file->event_call;
274 if (!event_call || !event_call->event.funcs ||
275 !event_call->event.funcs->trace)
276 return;
277
278 event = &fbuffer->trace_file->event_call->event;
279
280 spin_lock_irqsave(&tracepoint_iter_lock, flags);
281 trace_seq_init(&iter->seq);
282 iter->ent = fbuffer->entry;
283 event_call->event.funcs->trace(iter, 0, event);
284 trace_seq_putc(&iter->seq, 0);
285 printk("%s", iter->seq.buffer);
286
287 spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
288}
289
290void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
291{
292 if (tracepoint_printk)
293 output_printk(fbuffer);
294
295 event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer,
296 fbuffer->event, fbuffer->entry,
297 fbuffer->flags, fbuffer->pc);
298}
299EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
300
301int trace_event_reg(struct trace_event_call *call,
302 enum trace_reg type, void *data)
303{
304 struct trace_event_file *file = data;
305
306 WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
307 switch (type) {
308 case TRACE_REG_REGISTER:
309 return tracepoint_probe_register(call->tp,
310 call->class->probe,
311 file);
312 case TRACE_REG_UNREGISTER:
313 tracepoint_probe_unregister(call->tp,
314 call->class->probe,
315 file);
316 return 0;
317
318#ifdef CONFIG_PERF_EVENTS
319 case TRACE_REG_PERF_REGISTER:
320 return tracepoint_probe_register(call->tp,
321 call->class->perf_probe,
322 call);
323 case TRACE_REG_PERF_UNREGISTER:
324 tracepoint_probe_unregister(call->tp,
325 call->class->perf_probe,
326 call);
327 return 0;
328 case TRACE_REG_PERF_OPEN:
329 case TRACE_REG_PERF_CLOSE:
330 case TRACE_REG_PERF_ADD:
331 case TRACE_REG_PERF_DEL:
332 return 0;
333#endif
334 }
335 return 0;
336}
337EXPORT_SYMBOL_GPL(trace_event_reg);
338
339void trace_event_enable_cmd_record(bool enable)
340{
341 struct trace_event_file *file;
342 struct trace_array *tr;
343
344 mutex_lock(&event_mutex);
345 do_for_each_event_file(tr, file) {
346
347 if (!(file->flags & EVENT_FILE_FL_ENABLED))
348 continue;
349
350 if (enable) {
351 tracing_start_cmdline_record();
352 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
353 } else {
354 tracing_stop_cmdline_record();
355 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
356 }
357 } while_for_each_event_file();
358 mutex_unlock(&event_mutex);
359}
360
361static int __ftrace_event_enable_disable(struct trace_event_file *file,
362 int enable, int soft_disable)
363{
364 struct trace_event_call *call = file->event_call;
365 struct trace_array *tr = file->tr;
366 int ret = 0;
367 int disable;
368
369 switch (enable) {
370 case 0:
371 /*
372 * When soft_disable is set and enable is cleared, the sm_ref
373 * reference counter is decremented. If it reaches 0, we want
374 * to clear the SOFT_DISABLED flag but leave the event in the
375 * state that it was. That is, if the event was enabled and
376 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
377 * is set we do not want the event to be enabled before we
378 * clear the bit.
379 *
380 * When soft_disable is not set but the SOFT_MODE flag is,
381 * we do nothing. Do not disable the tracepoint, otherwise
382 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
383 */
384 if (soft_disable) {
385 if (atomic_dec_return(&file->sm_ref) > 0)
386 break;
387 disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
388 clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
389 } else
390 disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
391
392 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
393 clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
394 if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
395 tracing_stop_cmdline_record();
396 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
397 }
398 call->class->reg(call, TRACE_REG_UNREGISTER, file);
399 }
400 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
401 if (file->flags & EVENT_FILE_FL_SOFT_MODE)
402 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
403 else
404 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
405 break;
406 case 1:
407 /*
408 * When soft_disable is set and enable is set, we want to
409 * register the tracepoint for the event, but leave the event
410 * as is. That means, if the event was already enabled, we do
411 * nothing (but set SOFT_MODE). If the event is disabled, we
412 * set SOFT_DISABLED before enabling the event tracepoint, so
413 * it still seems to be disabled.
414 */
415 if (!soft_disable)
416 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
417 else {
418 if (atomic_inc_return(&file->sm_ref) > 1)
419 break;
420 set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
421 }
422
423 if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
424
425 /* Keep the event disabled, when going to SOFT_MODE. */
426 if (soft_disable)
427 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
428
429 if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
430 tracing_start_cmdline_record();
431 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
432 }
433 ret = call->class->reg(call, TRACE_REG_REGISTER, file);
434 if (ret) {
435 tracing_stop_cmdline_record();
436 pr_info("event trace: Could not enable event "
437 "%s\n", trace_event_name(call));
438 break;
439 }
440 set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
441
442 /* WAS_ENABLED gets set but never cleared. */
443 call->flags |= TRACE_EVENT_FL_WAS_ENABLED;
444 }
445 break;
446 }
447
448 return ret;
449}
450
451int trace_event_enable_disable(struct trace_event_file *file,
452 int enable, int soft_disable)
453{
454 return __ftrace_event_enable_disable(file, enable, soft_disable);
455}
456
457static int ftrace_event_enable_disable(struct trace_event_file *file,
458 int enable)
459{
460 return __ftrace_event_enable_disable(file, enable, 0);
461}
462
463static void ftrace_clear_events(struct trace_array *tr)
464{
465 struct trace_event_file *file;
466
467 mutex_lock(&event_mutex);
468 list_for_each_entry(file, &tr->events, list) {
469 ftrace_event_enable_disable(file, 0);
470 }
471 mutex_unlock(&event_mutex);
472}
473
474static int cmp_pid(const void *key, const void *elt)
475{
476 const pid_t *search_pid = key;
477 const pid_t *pid = elt;
478
479 if (*search_pid == *pid)
480 return 0;
481 if (*search_pid < *pid)
482 return -1;
483 return 1;
484}
485
486static bool
487check_ignore_pid(struct trace_pid_list *filtered_pids, struct task_struct *task)
488{
489 pid_t search_pid;
490 pid_t *pid;
491
492 /*
493 * Return false, because if filtered_pids does not exist,
494 * all pids are good to trace.
495 */
496 if (!filtered_pids)
497 return false;
498
499 search_pid = task->pid;
500
501 pid = bsearch(&search_pid, filtered_pids->pids,
502 filtered_pids->nr_pids, sizeof(pid_t),
503 cmp_pid);
504 if (!pid)
505 return true;
506
507 return false;
508}
509
510static void
511event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
512 struct task_struct *prev, struct task_struct *next)
513{
514 struct trace_array *tr = data;
515 struct trace_pid_list *pid_list;
516
517 pid_list = rcu_dereference_sched(tr->filtered_pids);
518
519 this_cpu_write(tr->trace_buffer.data->ignore_pid,
520 check_ignore_pid(pid_list, prev) &&
521 check_ignore_pid(pid_list, next));
522}
523
524static void
525event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
526 struct task_struct *prev, struct task_struct *next)
527{
528 struct trace_array *tr = data;
529 struct trace_pid_list *pid_list;
530
531 pid_list = rcu_dereference_sched(tr->filtered_pids);
532
533 this_cpu_write(tr->trace_buffer.data->ignore_pid,
534 check_ignore_pid(pid_list, next));
535}
536
537static void
538event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
539{
540 struct trace_array *tr = data;
541 struct trace_pid_list *pid_list;
542
543 /* Nothing to do if we are already tracing */
544 if (!this_cpu_read(tr->trace_buffer.data->ignore_pid))
545 return;
546
547 pid_list = rcu_dereference_sched(tr->filtered_pids);
548
549 this_cpu_write(tr->trace_buffer.data->ignore_pid,
550 check_ignore_pid(pid_list, task));
551}
552
553static void
554event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
555{
556 struct trace_array *tr = data;
557 struct trace_pid_list *pid_list;
558
559 /* Nothing to do if we are not tracing */
560 if (this_cpu_read(tr->trace_buffer.data->ignore_pid))
561 return;
562
563 pid_list = rcu_dereference_sched(tr->filtered_pids);
564
565 /* Set tracing if current is enabled */
566 this_cpu_write(tr->trace_buffer.data->ignore_pid,
567 check_ignore_pid(pid_list, current));
568}
569
570static void __ftrace_clear_event_pids(struct trace_array *tr)
571{
572 struct trace_pid_list *pid_list;
573 struct trace_event_file *file;
574 int cpu;
575
576 pid_list = rcu_dereference_protected(tr->filtered_pids,
577 lockdep_is_held(&event_mutex));
578 if (!pid_list)
579 return;
580
581 unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
582 unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
583
584 unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
585 unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
586
587 unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
588 unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
589
590 unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
591 unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
592
593 list_for_each_entry(file, &tr->events, list) {
594 clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
595 }
596
597 for_each_possible_cpu(cpu)
598 per_cpu_ptr(tr->trace_buffer.data, cpu)->ignore_pid = false;
599
600 rcu_assign_pointer(tr->filtered_pids, NULL);
601
602 /* Wait till all users are no longer using pid filtering */
603 synchronize_sched();
604
605 free_pages((unsigned long)pid_list->pids, pid_list->order);
606 kfree(pid_list);
607}
608
609static void ftrace_clear_event_pids(struct trace_array *tr)
610{
611 mutex_lock(&event_mutex);
612 __ftrace_clear_event_pids(tr);
613 mutex_unlock(&event_mutex);
614}
615
616static void __put_system(struct event_subsystem *system)
617{
618 struct event_filter *filter = system->filter;
619
620 WARN_ON_ONCE(system_refcount(system) == 0);
621 if (system_refcount_dec(system))
622 return;
623
624 list_del(&system->list);
625
626 if (filter) {
627 kfree(filter->filter_string);
628 kfree(filter);
629 }
630 kfree_const(system->name);
631 kfree(system);
632}
633
634static void __get_system(struct event_subsystem *system)
635{
636 WARN_ON_ONCE(system_refcount(system) == 0);
637 system_refcount_inc(system);
638}
639
640static void __get_system_dir(struct trace_subsystem_dir *dir)
641{
642 WARN_ON_ONCE(dir->ref_count == 0);
643 dir->ref_count++;
644 __get_system(dir->subsystem);
645}
646
647static void __put_system_dir(struct trace_subsystem_dir *dir)
648{
649 WARN_ON_ONCE(dir->ref_count == 0);
650 /* If the subsystem is about to be freed, the dir must be too */
651 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
652
653 __put_system(dir->subsystem);
654 if (!--dir->ref_count)
655 kfree(dir);
656}
657
658static void put_system(struct trace_subsystem_dir *dir)
659{
660 mutex_lock(&event_mutex);
661 __put_system_dir(dir);
662 mutex_unlock(&event_mutex);
663}
664
665static void remove_subsystem(struct trace_subsystem_dir *dir)
666{
667 if (!dir)
668 return;
669
670 if (!--dir->nr_events) {
671 tracefs_remove_recursive(dir->entry);
672 list_del(&dir->list);
673 __put_system_dir(dir);
674 }
675}
676
677static void remove_event_file_dir(struct trace_event_file *file)
678{
679 struct dentry *dir = file->dir;
680 struct dentry *child;
681
682 if (dir) {
683 spin_lock(&dir->d_lock); /* probably unneeded */
684 list_for_each_entry(child, &dir->d_subdirs, d_child) {
685 if (d_really_is_positive(child)) /* probably unneeded */
686 d_inode(child)->i_private = NULL;
687 }
688 spin_unlock(&dir->d_lock);
689
690 tracefs_remove_recursive(dir);
691 }
692
693 list_del(&file->list);
694 remove_subsystem(file->system);
695 free_event_filter(file->filter);
696 kmem_cache_free(file_cachep, file);
697}
698
699/*
700 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
701 */
702static int
703__ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
704 const char *sub, const char *event, int set)
705{
706 struct trace_event_file *file;
707 struct trace_event_call *call;
708 const char *name;
709 int ret = -EINVAL;
710
711 list_for_each_entry(file, &tr->events, list) {
712
713 call = file->event_call;
714 name = trace_event_name(call);
715
716 if (!name || !call->class || !call->class->reg)
717 continue;
718
719 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
720 continue;
721
722 if (match &&
723 strcmp(match, name) != 0 &&
724 strcmp(match, call->class->system) != 0)
725 continue;
726
727 if (sub && strcmp(sub, call->class->system) != 0)
728 continue;
729
730 if (event && strcmp(event, name) != 0)
731 continue;
732
733 ftrace_event_enable_disable(file, set);
734
735 ret = 0;
736 }
737
738 return ret;
739}
740
741static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
742 const char *sub, const char *event, int set)
743{
744 int ret;
745
746 mutex_lock(&event_mutex);
747 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
748 mutex_unlock(&event_mutex);
749
750 return ret;
751}
752
753static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
754{
755 char *event = NULL, *sub = NULL, *match;
756 int ret;
757
758 /*
759 * The buf format can be <subsystem>:<event-name>
760 * *:<event-name> means any event by that name.
761 * :<event-name> is the same.
762 *
763 * <subsystem>:* means all events in that subsystem
764 * <subsystem>: means the same.
765 *
766 * <name> (no ':') means all events in a subsystem with
767 * the name <name> or any event that matches <name>
768 */
769
770 match = strsep(&buf, ":");
771 if (buf) {
772 sub = match;
773 event = buf;
774 match = NULL;
775
776 if (!strlen(sub) || strcmp(sub, "*") == 0)
777 sub = NULL;
778 if (!strlen(event) || strcmp(event, "*") == 0)
779 event = NULL;
780 }
781
782 ret = __ftrace_set_clr_event(tr, match, sub, event, set);
783
784 /* Put back the colon to allow this to be called again */
785 if (buf)
786 *(buf - 1) = ':';
787
788 return ret;
789}
790
791/**
792 * trace_set_clr_event - enable or disable an event
793 * @system: system name to match (NULL for any system)
794 * @event: event name to match (NULL for all events, within system)
795 * @set: 1 to enable, 0 to disable
796 *
797 * This is a way for other parts of the kernel to enable or disable
798 * event recording.
799 *
800 * Returns 0 on success, -EINVAL if the parameters do not match any
801 * registered events.
802 */
803int trace_set_clr_event(const char *system, const char *event, int set)
804{
805 struct trace_array *tr = top_trace_array();
806
807 if (!tr)
808 return -ENODEV;
809
810 return __ftrace_set_clr_event(tr, NULL, system, event, set);
811}
812EXPORT_SYMBOL_GPL(trace_set_clr_event);
813
814/* 128 should be much more than enough */
815#define EVENT_BUF_SIZE 127
816
817static ssize_t
818ftrace_event_write(struct file *file, const char __user *ubuf,
819 size_t cnt, loff_t *ppos)
820{
821 struct trace_parser parser;
822 struct seq_file *m = file->private_data;
823 struct trace_array *tr = m->private;
824 ssize_t read, ret;
825
826 if (!cnt)
827 return 0;
828
829 ret = tracing_update_buffers();
830 if (ret < 0)
831 return ret;
832
833 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
834 return -ENOMEM;
835
836 read = trace_get_user(&parser, ubuf, cnt, ppos);
837
838 if (read >= 0 && trace_parser_loaded((&parser))) {
839 int set = 1;
840
841 if (*parser.buffer == '!')
842 set = 0;
843
844 parser.buffer[parser.idx] = 0;
845
846 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
847 if (ret)
848 goto out_put;
849 }
850
851 ret = read;
852
853 out_put:
854 trace_parser_put(&parser);
855
856 return ret;
857}
858
859static void *
860t_next(struct seq_file *m, void *v, loff_t *pos)
861{
862 struct trace_event_file *file = v;
863 struct trace_event_call *call;
864 struct trace_array *tr = m->private;
865
866 (*pos)++;
867
868 list_for_each_entry_continue(file, &tr->events, list) {
869 call = file->event_call;
870 /*
871 * The ftrace subsystem is for showing formats only.
872 * They can not be enabled or disabled via the event files.
873 */
874 if (call->class && call->class->reg &&
875 !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
876 return file;
877 }
878
879 return NULL;
880}
881
882static void *t_start(struct seq_file *m, loff_t *pos)
883{
884 struct trace_event_file *file;
885 struct trace_array *tr = m->private;
886 loff_t l;
887
888 mutex_lock(&event_mutex);
889
890 file = list_entry(&tr->events, struct trace_event_file, list);
891 for (l = 0; l <= *pos; ) {
892 file = t_next(m, file, &l);
893 if (!file)
894 break;
895 }
896 return file;
897}
898
899static void *
900s_next(struct seq_file *m, void *v, loff_t *pos)
901{
902 struct trace_event_file *file = v;
903 struct trace_array *tr = m->private;
904
905 (*pos)++;
906
907 list_for_each_entry_continue(file, &tr->events, list) {
908 if (file->flags & EVENT_FILE_FL_ENABLED)
909 return file;
910 }
911
912 return NULL;
913}
914
915static void *s_start(struct seq_file *m, loff_t *pos)
916{
917 struct trace_event_file *file;
918 struct trace_array *tr = m->private;
919 loff_t l;
920
921 mutex_lock(&event_mutex);
922
923 file = list_entry(&tr->events, struct trace_event_file, list);
924 for (l = 0; l <= *pos; ) {
925 file = s_next(m, file, &l);
926 if (!file)
927 break;
928 }
929 return file;
930}
931
932static int t_show(struct seq_file *m, void *v)
933{
934 struct trace_event_file *file = v;
935 struct trace_event_call *call = file->event_call;
936
937 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
938 seq_printf(m, "%s:", call->class->system);
939 seq_printf(m, "%s\n", trace_event_name(call));
940
941 return 0;
942}
943
944static void t_stop(struct seq_file *m, void *p)
945{
946 mutex_unlock(&event_mutex);
947}
948
949static void *p_start(struct seq_file *m, loff_t *pos)
950 __acquires(RCU)
951{
952 struct trace_pid_list *pid_list;
953 struct trace_array *tr = m->private;
954
955 /*
956 * Grab the mutex, to keep calls to p_next() having the same
957 * tr->filtered_pids as p_start() has.
958 * If we just passed the tr->filtered_pids around, then RCU would
959 * have been enough, but doing that makes things more complex.
960 */
961 mutex_lock(&event_mutex);
962 rcu_read_lock_sched();
963
964 pid_list = rcu_dereference_sched(tr->filtered_pids);
965
966 if (!pid_list || *pos >= pid_list->nr_pids)
967 return NULL;
968
969 return (void *)&pid_list->pids[*pos];
970}
971
972static void p_stop(struct seq_file *m, void *p)
973 __releases(RCU)
974{
975 rcu_read_unlock_sched();
976 mutex_unlock(&event_mutex);
977}
978
979static void *
980p_next(struct seq_file *m, void *v, loff_t *pos)
981{
982 struct trace_array *tr = m->private;
983 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids);
984
985 (*pos)++;
986
987 if (*pos >= pid_list->nr_pids)
988 return NULL;
989
990 return (void *)&pid_list->pids[*pos];
991}
992
993static int p_show(struct seq_file *m, void *v)
994{
995 pid_t *pid = v;
996
997 seq_printf(m, "%d\n", *pid);
998 return 0;
999}
1000
1001static ssize_t
1002event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1003 loff_t *ppos)
1004{
1005 struct trace_event_file *file;
1006 unsigned long flags;
1007 char buf[4] = "0";
1008
1009 mutex_lock(&event_mutex);
1010 file = event_file_data(filp);
1011 if (likely(file))
1012 flags = file->flags;
1013 mutex_unlock(&event_mutex);
1014
1015 if (!file)
1016 return -ENODEV;
1017
1018 if (flags & EVENT_FILE_FL_ENABLED &&
1019 !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1020 strcpy(buf, "1");
1021
1022 if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1023 flags & EVENT_FILE_FL_SOFT_MODE)
1024 strcat(buf, "*");
1025
1026 strcat(buf, "\n");
1027
1028 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1029}
1030
1031static ssize_t
1032event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1033 loff_t *ppos)
1034{
1035 struct trace_event_file *file;
1036 unsigned long val;
1037 int ret;
1038
1039 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1040 if (ret)
1041 return ret;
1042
1043 ret = tracing_update_buffers();
1044 if (ret < 0)
1045 return ret;
1046
1047 switch (val) {
1048 case 0:
1049 case 1:
1050 ret = -ENODEV;
1051 mutex_lock(&event_mutex);
1052 file = event_file_data(filp);
1053 if (likely(file))
1054 ret = ftrace_event_enable_disable(file, val);
1055 mutex_unlock(&event_mutex);
1056 break;
1057
1058 default:
1059 return -EINVAL;
1060 }
1061
1062 *ppos += cnt;
1063
1064 return ret ? ret : cnt;
1065}
1066
1067static ssize_t
1068system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1069 loff_t *ppos)
1070{
1071 const char set_to_char[4] = { '?', '0', '1', 'X' };
1072 struct trace_subsystem_dir *dir = filp->private_data;
1073 struct event_subsystem *system = dir->subsystem;
1074 struct trace_event_call *call;
1075 struct trace_event_file *file;
1076 struct trace_array *tr = dir->tr;
1077 char buf[2];
1078 int set = 0;
1079 int ret;
1080
1081 mutex_lock(&event_mutex);
1082 list_for_each_entry(file, &tr->events, list) {
1083 call = file->event_call;
1084 if (!trace_event_name(call) || !call->class || !call->class->reg)
1085 continue;
1086
1087 if (system && strcmp(call->class->system, system->name) != 0)
1088 continue;
1089
1090 /*
1091 * We need to find out if all the events are set
1092 * or if all events or cleared, or if we have
1093 * a mixture.
1094 */
1095 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1096
1097 /*
1098 * If we have a mixture, no need to look further.
1099 */
1100 if (set == 3)
1101 break;
1102 }
1103 mutex_unlock(&event_mutex);
1104
1105 buf[0] = set_to_char[set];
1106 buf[1] = '\n';
1107
1108 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1109
1110 return ret;
1111}
1112
1113static ssize_t
1114system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1115 loff_t *ppos)
1116{
1117 struct trace_subsystem_dir *dir = filp->private_data;
1118 struct event_subsystem *system = dir->subsystem;
1119 const char *name = NULL;
1120 unsigned long val;
1121 ssize_t ret;
1122
1123 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1124 if (ret)
1125 return ret;
1126
1127 ret = tracing_update_buffers();
1128 if (ret < 0)
1129 return ret;
1130
1131 if (val != 0 && val != 1)
1132 return -EINVAL;
1133
1134 /*
1135 * Opening of "enable" adds a ref count to system,
1136 * so the name is safe to use.
1137 */
1138 if (system)
1139 name = system->name;
1140
1141 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1142 if (ret)
1143 goto out;
1144
1145 ret = cnt;
1146
1147out:
1148 *ppos += cnt;
1149
1150 return ret;
1151}
1152
1153enum {
1154 FORMAT_HEADER = 1,
1155 FORMAT_FIELD_SEPERATOR = 2,
1156 FORMAT_PRINTFMT = 3,
1157};
1158
1159static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1160{
1161 struct trace_event_call *call = event_file_data(m->private);
1162 struct list_head *common_head = &ftrace_common_fields;
1163 struct list_head *head = trace_get_fields(call);
1164 struct list_head *node = v;
1165
1166 (*pos)++;
1167
1168 switch ((unsigned long)v) {
1169 case FORMAT_HEADER:
1170 node = common_head;
1171 break;
1172
1173 case FORMAT_FIELD_SEPERATOR:
1174 node = head;
1175 break;
1176
1177 case FORMAT_PRINTFMT:
1178 /* all done */
1179 return NULL;
1180 }
1181
1182 node = node->prev;
1183 if (node == common_head)
1184 return (void *)FORMAT_FIELD_SEPERATOR;
1185 else if (node == head)
1186 return (void *)FORMAT_PRINTFMT;
1187 else
1188 return node;
1189}
1190
1191static int f_show(struct seq_file *m, void *v)
1192{
1193 struct trace_event_call *call = event_file_data(m->private);
1194 struct ftrace_event_field *field;
1195 const char *array_descriptor;
1196
1197 switch ((unsigned long)v) {
1198 case FORMAT_HEADER:
1199 seq_printf(m, "name: %s\n", trace_event_name(call));
1200 seq_printf(m, "ID: %d\n", call->event.type);
1201 seq_puts(m, "format:\n");
1202 return 0;
1203
1204 case FORMAT_FIELD_SEPERATOR:
1205 seq_putc(m, '\n');
1206 return 0;
1207
1208 case FORMAT_PRINTFMT:
1209 seq_printf(m, "\nprint fmt: %s\n",
1210 call->print_fmt);
1211 return 0;
1212 }
1213
1214 field = list_entry(v, struct ftrace_event_field, link);
1215 /*
1216 * Smartly shows the array type(except dynamic array).
1217 * Normal:
1218 * field:TYPE VAR
1219 * If TYPE := TYPE[LEN], it is shown:
1220 * field:TYPE VAR[LEN]
1221 */
1222 array_descriptor = strchr(field->type, '[');
1223
1224 if (!strncmp(field->type, "__data_loc", 10))
1225 array_descriptor = NULL;
1226
1227 if (!array_descriptor)
1228 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1229 field->type, field->name, field->offset,
1230 field->size, !!field->is_signed);
1231 else
1232 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1233 (int)(array_descriptor - field->type),
1234 field->type, field->name,
1235 array_descriptor, field->offset,
1236 field->size, !!field->is_signed);
1237
1238 return 0;
1239}
1240
1241static void *f_start(struct seq_file *m, loff_t *pos)
1242{
1243 void *p = (void *)FORMAT_HEADER;
1244 loff_t l = 0;
1245
1246 /* ->stop() is called even if ->start() fails */
1247 mutex_lock(&event_mutex);
1248 if (!event_file_data(m->private))
1249 return ERR_PTR(-ENODEV);
1250
1251 while (l < *pos && p)
1252 p = f_next(m, p, &l);
1253
1254 return p;
1255}
1256
1257static void f_stop(struct seq_file *m, void *p)
1258{
1259 mutex_unlock(&event_mutex);
1260}
1261
1262static const struct seq_operations trace_format_seq_ops = {
1263 .start = f_start,
1264 .next = f_next,
1265 .stop = f_stop,
1266 .show = f_show,
1267};
1268
1269static int trace_format_open(struct inode *inode, struct file *file)
1270{
1271 struct seq_file *m;
1272 int ret;
1273
1274 ret = seq_open(file, &trace_format_seq_ops);
1275 if (ret < 0)
1276 return ret;
1277
1278 m = file->private_data;
1279 m->private = file;
1280
1281 return 0;
1282}
1283
1284static ssize_t
1285event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1286{
1287 int id = (long)event_file_data(filp);
1288 char buf[32];
1289 int len;
1290
1291 if (*ppos)
1292 return 0;
1293
1294 if (unlikely(!id))
1295 return -ENODEV;
1296
1297 len = sprintf(buf, "%d\n", id);
1298
1299 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1300}
1301
1302static ssize_t
1303event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1304 loff_t *ppos)
1305{
1306 struct trace_event_file *file;
1307 struct trace_seq *s;
1308 int r = -ENODEV;
1309
1310 if (*ppos)
1311 return 0;
1312
1313 s = kmalloc(sizeof(*s), GFP_KERNEL);
1314
1315 if (!s)
1316 return -ENOMEM;
1317
1318 trace_seq_init(s);
1319
1320 mutex_lock(&event_mutex);
1321 file = event_file_data(filp);
1322 if (file)
1323 print_event_filter(file, s);
1324 mutex_unlock(&event_mutex);
1325
1326 if (file)
1327 r = simple_read_from_buffer(ubuf, cnt, ppos,
1328 s->buffer, trace_seq_used(s));
1329
1330 kfree(s);
1331
1332 return r;
1333}
1334
1335static ssize_t
1336event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1337 loff_t *ppos)
1338{
1339 struct trace_event_file *file;
1340 char *buf;
1341 int err = -ENODEV;
1342
1343 if (cnt >= PAGE_SIZE)
1344 return -EINVAL;
1345
1346 buf = memdup_user_nul(ubuf, cnt);
1347 if (IS_ERR(buf))
1348 return PTR_ERR(buf);
1349
1350 mutex_lock(&event_mutex);
1351 file = event_file_data(filp);
1352 if (file)
1353 err = apply_event_filter(file, buf);
1354 mutex_unlock(&event_mutex);
1355
1356 kfree(buf);
1357 if (err < 0)
1358 return err;
1359
1360 *ppos += cnt;
1361
1362 return cnt;
1363}
1364
1365static LIST_HEAD(event_subsystems);
1366
1367static int subsystem_open(struct inode *inode, struct file *filp)
1368{
1369 struct event_subsystem *system = NULL;
1370 struct trace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1371 struct trace_array *tr;
1372 int ret;
1373
1374 if (tracing_is_disabled())
1375 return -ENODEV;
1376
1377 /* Make sure the system still exists */
1378 mutex_lock(&trace_types_lock);
1379 mutex_lock(&event_mutex);
1380 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1381 list_for_each_entry(dir, &tr->systems, list) {
1382 if (dir == inode->i_private) {
1383 /* Don't open systems with no events */
1384 if (dir->nr_events) {
1385 __get_system_dir(dir);
1386 system = dir->subsystem;
1387 }
1388 goto exit_loop;
1389 }
1390 }
1391 }
1392 exit_loop:
1393 mutex_unlock(&event_mutex);
1394 mutex_unlock(&trace_types_lock);
1395
1396 if (!system)
1397 return -ENODEV;
1398
1399 /* Some versions of gcc think dir can be uninitialized here */
1400 WARN_ON(!dir);
1401
1402 /* Still need to increment the ref count of the system */
1403 if (trace_array_get(tr) < 0) {
1404 put_system(dir);
1405 return -ENODEV;
1406 }
1407
1408 ret = tracing_open_generic(inode, filp);
1409 if (ret < 0) {
1410 trace_array_put(tr);
1411 put_system(dir);
1412 }
1413
1414 return ret;
1415}
1416
1417static int system_tr_open(struct inode *inode, struct file *filp)
1418{
1419 struct trace_subsystem_dir *dir;
1420 struct trace_array *tr = inode->i_private;
1421 int ret;
1422
1423 if (tracing_is_disabled())
1424 return -ENODEV;
1425
1426 if (trace_array_get(tr) < 0)
1427 return -ENODEV;
1428
1429 /* Make a temporary dir that has no system but points to tr */
1430 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1431 if (!dir) {
1432 trace_array_put(tr);
1433 return -ENOMEM;
1434 }
1435
1436 dir->tr = tr;
1437
1438 ret = tracing_open_generic(inode, filp);
1439 if (ret < 0) {
1440 trace_array_put(tr);
1441 kfree(dir);
1442 return ret;
1443 }
1444
1445 filp->private_data = dir;
1446
1447 return 0;
1448}
1449
1450static int subsystem_release(struct inode *inode, struct file *file)
1451{
1452 struct trace_subsystem_dir *dir = file->private_data;
1453
1454 trace_array_put(dir->tr);
1455
1456 /*
1457 * If dir->subsystem is NULL, then this is a temporary
1458 * descriptor that was made for a trace_array to enable
1459 * all subsystems.
1460 */
1461 if (dir->subsystem)
1462 put_system(dir);
1463 else
1464 kfree(dir);
1465
1466 return 0;
1467}
1468
1469static ssize_t
1470subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1471 loff_t *ppos)
1472{
1473 struct trace_subsystem_dir *dir = filp->private_data;
1474 struct event_subsystem *system = dir->subsystem;
1475 struct trace_seq *s;
1476 int r;
1477
1478 if (*ppos)
1479 return 0;
1480
1481 s = kmalloc(sizeof(*s), GFP_KERNEL);
1482 if (!s)
1483 return -ENOMEM;
1484
1485 trace_seq_init(s);
1486
1487 print_subsystem_event_filter(system, s);
1488 r = simple_read_from_buffer(ubuf, cnt, ppos,
1489 s->buffer, trace_seq_used(s));
1490
1491 kfree(s);
1492
1493 return r;
1494}
1495
1496static ssize_t
1497subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1498 loff_t *ppos)
1499{
1500 struct trace_subsystem_dir *dir = filp->private_data;
1501 char *buf;
1502 int err;
1503
1504 if (cnt >= PAGE_SIZE)
1505 return -EINVAL;
1506
1507 buf = memdup_user_nul(ubuf, cnt);
1508 if (IS_ERR(buf))
1509 return PTR_ERR(buf);
1510
1511 err = apply_subsystem_event_filter(dir, buf);
1512 kfree(buf);
1513 if (err < 0)
1514 return err;
1515
1516 *ppos += cnt;
1517
1518 return cnt;
1519}
1520
1521static ssize_t
1522show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1523{
1524 int (*func)(struct trace_seq *s) = filp->private_data;
1525 struct trace_seq *s;
1526 int r;
1527
1528 if (*ppos)
1529 return 0;
1530
1531 s = kmalloc(sizeof(*s), GFP_KERNEL);
1532 if (!s)
1533 return -ENOMEM;
1534
1535 trace_seq_init(s);
1536
1537 func(s);
1538 r = simple_read_from_buffer(ubuf, cnt, ppos,
1539 s->buffer, trace_seq_used(s));
1540
1541 kfree(s);
1542
1543 return r;
1544}
1545
1546static int max_pids(struct trace_pid_list *pid_list)
1547{
1548 return (PAGE_SIZE << pid_list->order) / sizeof(pid_t);
1549}
1550
1551static void ignore_task_cpu(void *data)
1552{
1553 struct trace_array *tr = data;
1554 struct trace_pid_list *pid_list;
1555
1556 /*
1557 * This function is called by on_each_cpu() while the
1558 * event_mutex is held.
1559 */
1560 pid_list = rcu_dereference_protected(tr->filtered_pids,
1561 mutex_is_locked(&event_mutex));
1562
1563 this_cpu_write(tr->trace_buffer.data->ignore_pid,
1564 check_ignore_pid(pid_list, current));
1565}
1566
1567static ssize_t
1568ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
1569 size_t cnt, loff_t *ppos)
1570{
1571 struct seq_file *m = filp->private_data;
1572 struct trace_array *tr = m->private;
1573 struct trace_pid_list *filtered_pids = NULL;
1574 struct trace_pid_list *pid_list = NULL;
1575 struct trace_event_file *file;
1576 struct trace_parser parser;
1577 unsigned long val;
1578 loff_t this_pos;
1579 ssize_t read = 0;
1580 ssize_t ret = 0;
1581 pid_t pid;
1582 int i;
1583
1584 if (!cnt)
1585 return 0;
1586
1587 ret = tracing_update_buffers();
1588 if (ret < 0)
1589 return ret;
1590
1591 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
1592 return -ENOMEM;
1593
1594 mutex_lock(&event_mutex);
1595 /*
1596 * Load as many pids into the array before doing a
1597 * swap from the tr->filtered_pids to the new list.
1598 */
1599 while (cnt > 0) {
1600
1601 this_pos = 0;
1602
1603 ret = trace_get_user(&parser, ubuf, cnt, &this_pos);
1604 if (ret < 0 || !trace_parser_loaded(&parser))
1605 break;
1606
1607 read += ret;
1608 ubuf += ret;
1609 cnt -= ret;
1610
1611 parser.buffer[parser.idx] = 0;
1612
1613 ret = -EINVAL;
1614 if (kstrtoul(parser.buffer, 0, &val))
1615 break;
1616 if (val > INT_MAX)
1617 break;
1618
1619 pid = (pid_t)val;
1620
1621 ret = -ENOMEM;
1622 if (!pid_list) {
1623 pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
1624 if (!pid_list)
1625 break;
1626
1627 filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1628 lockdep_is_held(&event_mutex));
1629 if (filtered_pids)
1630 pid_list->order = filtered_pids->order;
1631 else
1632 pid_list->order = 0;
1633
1634 pid_list->pids = (void *)__get_free_pages(GFP_KERNEL,
1635 pid_list->order);
1636 if (!pid_list->pids)
1637 break;
1638
1639 if (filtered_pids) {
1640 pid_list->nr_pids = filtered_pids->nr_pids;
1641 memcpy(pid_list->pids, filtered_pids->pids,
1642 pid_list->nr_pids * sizeof(pid_t));
1643 } else
1644 pid_list->nr_pids = 0;
1645 }
1646
1647 if (pid_list->nr_pids >= max_pids(pid_list)) {
1648 pid_t *pid_page;
1649
1650 pid_page = (void *)__get_free_pages(GFP_KERNEL,
1651 pid_list->order + 1);
1652 if (!pid_page)
1653 break;
1654 memcpy(pid_page, pid_list->pids,
1655 pid_list->nr_pids * sizeof(pid_t));
1656 free_pages((unsigned long)pid_list->pids, pid_list->order);
1657
1658 pid_list->order++;
1659 pid_list->pids = pid_page;
1660 }
1661
1662 pid_list->pids[pid_list->nr_pids++] = pid;
1663 trace_parser_clear(&parser);
1664 ret = 0;
1665 }
1666 trace_parser_put(&parser);
1667
1668 if (ret < 0) {
1669 if (pid_list)
1670 free_pages((unsigned long)pid_list->pids, pid_list->order);
1671 kfree(pid_list);
1672 mutex_unlock(&event_mutex);
1673 return ret;
1674 }
1675
1676 if (!pid_list) {
1677 mutex_unlock(&event_mutex);
1678 return ret;
1679 }
1680
1681 sort(pid_list->pids, pid_list->nr_pids, sizeof(pid_t), cmp_pid, NULL);
1682
1683 /* Remove duplicates */
1684 for (i = 1; i < pid_list->nr_pids; i++) {
1685 int start = i;
1686
1687 while (i < pid_list->nr_pids &&
1688 pid_list->pids[i - 1] == pid_list->pids[i])
1689 i++;
1690
1691 if (start != i) {
1692 if (i < pid_list->nr_pids) {
1693 memmove(&pid_list->pids[start], &pid_list->pids[i],
1694 (pid_list->nr_pids - i) * sizeof(pid_t));
1695 pid_list->nr_pids -= i - start;
1696 i = start;
1697 } else
1698 pid_list->nr_pids = start;
1699 }
1700 }
1701
1702 rcu_assign_pointer(tr->filtered_pids, pid_list);
1703
1704 list_for_each_entry(file, &tr->events, list) {
1705 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
1706 }
1707
1708 if (filtered_pids) {
1709 synchronize_sched();
1710
1711 free_pages((unsigned long)filtered_pids->pids, filtered_pids->order);
1712 kfree(filtered_pids);
1713 } else {
1714 /*
1715 * Register a probe that is called before all other probes
1716 * to set ignore_pid if next or prev do not match.
1717 * Register a probe this is called after all other probes
1718 * to only keep ignore_pid set if next pid matches.
1719 */
1720 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1721 tr, INT_MAX);
1722 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1723 tr, 0);
1724
1725 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1726 tr, INT_MAX);
1727 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1728 tr, 0);
1729
1730 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1731 tr, INT_MAX);
1732 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1733 tr, 0);
1734
1735 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1736 tr, INT_MAX);
1737 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1738 tr, 0);
1739 }
1740
1741 /*
1742 * Ignoring of pids is done at task switch. But we have to
1743 * check for those tasks that are currently running.
1744 * Always do this in case a pid was appended or removed.
1745 */
1746 on_each_cpu(ignore_task_cpu, tr, 1);
1747
1748 mutex_unlock(&event_mutex);
1749
1750 ret = read;
1751 *ppos += read;
1752
1753 return ret;
1754}
1755
1756static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1757static int ftrace_event_set_open(struct inode *inode, struct file *file);
1758static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
1759static int ftrace_event_release(struct inode *inode, struct file *file);
1760
1761static const struct seq_operations show_event_seq_ops = {
1762 .start = t_start,
1763 .next = t_next,
1764 .show = t_show,
1765 .stop = t_stop,
1766};
1767
1768static const struct seq_operations show_set_event_seq_ops = {
1769 .start = s_start,
1770 .next = s_next,
1771 .show = t_show,
1772 .stop = t_stop,
1773};
1774
1775static const struct seq_operations show_set_pid_seq_ops = {
1776 .start = p_start,
1777 .next = p_next,
1778 .show = p_show,
1779 .stop = p_stop,
1780};
1781
1782static const struct file_operations ftrace_avail_fops = {
1783 .open = ftrace_event_avail_open,
1784 .read = seq_read,
1785 .llseek = seq_lseek,
1786 .release = seq_release,
1787};
1788
1789static const struct file_operations ftrace_set_event_fops = {
1790 .open = ftrace_event_set_open,
1791 .read = seq_read,
1792 .write = ftrace_event_write,
1793 .llseek = seq_lseek,
1794 .release = ftrace_event_release,
1795};
1796
1797static const struct file_operations ftrace_set_event_pid_fops = {
1798 .open = ftrace_event_set_pid_open,
1799 .read = seq_read,
1800 .write = ftrace_event_pid_write,
1801 .llseek = seq_lseek,
1802 .release = ftrace_event_release,
1803};
1804
1805static const struct file_operations ftrace_enable_fops = {
1806 .open = tracing_open_generic,
1807 .read = event_enable_read,
1808 .write = event_enable_write,
1809 .llseek = default_llseek,
1810};
1811
1812static const struct file_operations ftrace_event_format_fops = {
1813 .open = trace_format_open,
1814 .read = seq_read,
1815 .llseek = seq_lseek,
1816 .release = seq_release,
1817};
1818
1819static const struct file_operations ftrace_event_id_fops = {
1820 .read = event_id_read,
1821 .llseek = default_llseek,
1822};
1823
1824static const struct file_operations ftrace_event_filter_fops = {
1825 .open = tracing_open_generic,
1826 .read = event_filter_read,
1827 .write = event_filter_write,
1828 .llseek = default_llseek,
1829};
1830
1831static const struct file_operations ftrace_subsystem_filter_fops = {
1832 .open = subsystem_open,
1833 .read = subsystem_filter_read,
1834 .write = subsystem_filter_write,
1835 .llseek = default_llseek,
1836 .release = subsystem_release,
1837};
1838
1839static const struct file_operations ftrace_system_enable_fops = {
1840 .open = subsystem_open,
1841 .read = system_enable_read,
1842 .write = system_enable_write,
1843 .llseek = default_llseek,
1844 .release = subsystem_release,
1845};
1846
1847static const struct file_operations ftrace_tr_enable_fops = {
1848 .open = system_tr_open,
1849 .read = system_enable_read,
1850 .write = system_enable_write,
1851 .llseek = default_llseek,
1852 .release = subsystem_release,
1853};
1854
1855static const struct file_operations ftrace_show_header_fops = {
1856 .open = tracing_open_generic,
1857 .read = show_header,
1858 .llseek = default_llseek,
1859};
1860
1861static int
1862ftrace_event_open(struct inode *inode, struct file *file,
1863 const struct seq_operations *seq_ops)
1864{
1865 struct seq_file *m;
1866 int ret;
1867
1868 ret = seq_open(file, seq_ops);
1869 if (ret < 0)
1870 return ret;
1871 m = file->private_data;
1872 /* copy tr over to seq ops */
1873 m->private = inode->i_private;
1874
1875 return ret;
1876}
1877
1878static int ftrace_event_release(struct inode *inode, struct file *file)
1879{
1880 struct trace_array *tr = inode->i_private;
1881
1882 trace_array_put(tr);
1883
1884 return seq_release(inode, file);
1885}
1886
1887static int
1888ftrace_event_avail_open(struct inode *inode, struct file *file)
1889{
1890 const struct seq_operations *seq_ops = &show_event_seq_ops;
1891
1892 return ftrace_event_open(inode, file, seq_ops);
1893}
1894
1895static int
1896ftrace_event_set_open(struct inode *inode, struct file *file)
1897{
1898 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1899 struct trace_array *tr = inode->i_private;
1900 int ret;
1901
1902 if (trace_array_get(tr) < 0)
1903 return -ENODEV;
1904
1905 if ((file->f_mode & FMODE_WRITE) &&
1906 (file->f_flags & O_TRUNC))
1907 ftrace_clear_events(tr);
1908
1909 ret = ftrace_event_open(inode, file, seq_ops);
1910 if (ret < 0)
1911 trace_array_put(tr);
1912 return ret;
1913}
1914
1915static int
1916ftrace_event_set_pid_open(struct inode *inode, struct file *file)
1917{
1918 const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
1919 struct trace_array *tr = inode->i_private;
1920 int ret;
1921
1922 if (trace_array_get(tr) < 0)
1923 return -ENODEV;
1924
1925 if ((file->f_mode & FMODE_WRITE) &&
1926 (file->f_flags & O_TRUNC))
1927 ftrace_clear_event_pids(tr);
1928
1929 ret = ftrace_event_open(inode, file, seq_ops);
1930 if (ret < 0)
1931 trace_array_put(tr);
1932 return ret;
1933}
1934
1935static struct event_subsystem *
1936create_new_subsystem(const char *name)
1937{
1938 struct event_subsystem *system;
1939
1940 /* need to create new entry */
1941 system = kmalloc(sizeof(*system), GFP_KERNEL);
1942 if (!system)
1943 return NULL;
1944
1945 system->ref_count = 1;
1946
1947 /* Only allocate if dynamic (kprobes and modules) */
1948 system->name = kstrdup_const(name, GFP_KERNEL);
1949 if (!system->name)
1950 goto out_free;
1951
1952 system->filter = NULL;
1953
1954 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1955 if (!system->filter)
1956 goto out_free;
1957
1958 list_add(&system->list, &event_subsystems);
1959
1960 return system;
1961
1962 out_free:
1963 kfree_const(system->name);
1964 kfree(system);
1965 return NULL;
1966}
1967
1968static struct dentry *
1969event_subsystem_dir(struct trace_array *tr, const char *name,
1970 struct trace_event_file *file, struct dentry *parent)
1971{
1972 struct trace_subsystem_dir *dir;
1973 struct event_subsystem *system;
1974 struct dentry *entry;
1975
1976 /* First see if we did not already create this dir */
1977 list_for_each_entry(dir, &tr->systems, list) {
1978 system = dir->subsystem;
1979 if (strcmp(system->name, name) == 0) {
1980 dir->nr_events++;
1981 file->system = dir;
1982 return dir->entry;
1983 }
1984 }
1985
1986 /* Now see if the system itself exists. */
1987 list_for_each_entry(system, &event_subsystems, list) {
1988 if (strcmp(system->name, name) == 0)
1989 break;
1990 }
1991 /* Reset system variable when not found */
1992 if (&system->list == &event_subsystems)
1993 system = NULL;
1994
1995 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1996 if (!dir)
1997 goto out_fail;
1998
1999 if (!system) {
2000 system = create_new_subsystem(name);
2001 if (!system)
2002 goto out_free;
2003 } else
2004 __get_system(system);
2005
2006 dir->entry = tracefs_create_dir(name, parent);
2007 if (!dir->entry) {
2008 pr_warn("Failed to create system directory %s\n", name);
2009 __put_system(system);
2010 goto out_free;
2011 }
2012
2013 dir->tr = tr;
2014 dir->ref_count = 1;
2015 dir->nr_events = 1;
2016 dir->subsystem = system;
2017 file->system = dir;
2018
2019 entry = tracefs_create_file("filter", 0644, dir->entry, dir,
2020 &ftrace_subsystem_filter_fops);
2021 if (!entry) {
2022 kfree(system->filter);
2023 system->filter = NULL;
2024 pr_warn("Could not create tracefs '%s/filter' entry\n", name);
2025 }
2026
2027 trace_create_file("enable", 0644, dir->entry, dir,
2028 &ftrace_system_enable_fops);
2029
2030 list_add(&dir->list, &tr->systems);
2031
2032 return dir->entry;
2033
2034 out_free:
2035 kfree(dir);
2036 out_fail:
2037 /* Only print this message if failed on memory allocation */
2038 if (!dir || !system)
2039 pr_warn("No memory to create event subsystem %s\n", name);
2040 return NULL;
2041}
2042
2043static int
2044event_create_dir(struct dentry *parent, struct trace_event_file *file)
2045{
2046 struct trace_event_call *call = file->event_call;
2047 struct trace_array *tr = file->tr;
2048 struct list_head *head;
2049 struct dentry *d_events;
2050 const char *name;
2051 int ret;
2052
2053 /*
2054 * If the trace point header did not define TRACE_SYSTEM
2055 * then the system would be called "TRACE_SYSTEM".
2056 */
2057 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
2058 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
2059 if (!d_events)
2060 return -ENOMEM;
2061 } else
2062 d_events = parent;
2063
2064 name = trace_event_name(call);
2065 file->dir = tracefs_create_dir(name, d_events);
2066 if (!file->dir) {
2067 pr_warn("Could not create tracefs '%s' directory\n", name);
2068 return -1;
2069 }
2070
2071 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
2072 trace_create_file("enable", 0644, file->dir, file,
2073 &ftrace_enable_fops);
2074
2075#ifdef CONFIG_PERF_EVENTS
2076 if (call->event.type && call->class->reg)
2077 trace_create_file("id", 0444, file->dir,
2078 (void *)(long)call->event.type,
2079 &ftrace_event_id_fops);
2080#endif
2081
2082 /*
2083 * Other events may have the same class. Only update
2084 * the fields if they are not already defined.
2085 */
2086 head = trace_get_fields(call);
2087 if (list_empty(head)) {
2088 ret = call->class->define_fields(call);
2089 if (ret < 0) {
2090 pr_warn("Could not initialize trace point events/%s\n",
2091 name);
2092 return -1;
2093 }
2094 }
2095 trace_create_file("filter", 0644, file->dir, file,
2096 &ftrace_event_filter_fops);
2097
2098 /*
2099 * Only event directories that can be enabled should have
2100 * triggers.
2101 */
2102 if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
2103 trace_create_file("trigger", 0644, file->dir, file,
2104 &event_trigger_fops);
2105
2106 trace_create_file("format", 0444, file->dir, call,
2107 &ftrace_event_format_fops);
2108
2109 return 0;
2110}
2111
2112static void remove_event_from_tracers(struct trace_event_call *call)
2113{
2114 struct trace_event_file *file;
2115 struct trace_array *tr;
2116
2117 do_for_each_event_file_safe(tr, file) {
2118 if (file->event_call != call)
2119 continue;
2120
2121 remove_event_file_dir(file);
2122 /*
2123 * The do_for_each_event_file_safe() is
2124 * a double loop. After finding the call for this
2125 * trace_array, we use break to jump to the next
2126 * trace_array.
2127 */
2128 break;
2129 } while_for_each_event_file();
2130}
2131
2132static void event_remove(struct trace_event_call *call)
2133{
2134 struct trace_array *tr;
2135 struct trace_event_file *file;
2136
2137 do_for_each_event_file(tr, file) {
2138 if (file->event_call != call)
2139 continue;
2140 ftrace_event_enable_disable(file, 0);
2141 /*
2142 * The do_for_each_event_file() is
2143 * a double loop. After finding the call for this
2144 * trace_array, we use break to jump to the next
2145 * trace_array.
2146 */
2147 break;
2148 } while_for_each_event_file();
2149
2150 if (call->event.funcs)
2151 __unregister_trace_event(&call->event);
2152 remove_event_from_tracers(call);
2153 list_del(&call->list);
2154}
2155
2156static int event_init(struct trace_event_call *call)
2157{
2158 int ret = 0;
2159 const char *name;
2160
2161 name = trace_event_name(call);
2162 if (WARN_ON(!name))
2163 return -EINVAL;
2164
2165 if (call->class->raw_init) {
2166 ret = call->class->raw_init(call);
2167 if (ret < 0 && ret != -ENOSYS)
2168 pr_warn("Could not initialize trace events/%s\n", name);
2169 }
2170
2171 return ret;
2172}
2173
2174static int
2175__register_event(struct trace_event_call *call, struct module *mod)
2176{
2177 int ret;
2178
2179 ret = event_init(call);
2180 if (ret < 0)
2181 return ret;
2182
2183 list_add(&call->list, &ftrace_events);
2184 call->mod = mod;
2185
2186 return 0;
2187}
2188
2189static char *enum_replace(char *ptr, struct trace_enum_map *map, int len)
2190{
2191 int rlen;
2192 int elen;
2193
2194 /* Find the length of the enum value as a string */
2195 elen = snprintf(ptr, 0, "%ld", map->enum_value);
2196 /* Make sure there's enough room to replace the string with the value */
2197 if (len < elen)
2198 return NULL;
2199
2200 snprintf(ptr, elen + 1, "%ld", map->enum_value);
2201
2202 /* Get the rest of the string of ptr */
2203 rlen = strlen(ptr + len);
2204 memmove(ptr + elen, ptr + len, rlen);
2205 /* Make sure we end the new string */
2206 ptr[elen + rlen] = 0;
2207
2208 return ptr + elen;
2209}
2210
2211static void update_event_printk(struct trace_event_call *call,
2212 struct trace_enum_map *map)
2213{
2214 char *ptr;
2215 int quote = 0;
2216 int len = strlen(map->enum_string);
2217
2218 for (ptr = call->print_fmt; *ptr; ptr++) {
2219 if (*ptr == '\\') {
2220 ptr++;
2221 /* paranoid */
2222 if (!*ptr)
2223 break;
2224 continue;
2225 }
2226 if (*ptr == '"') {
2227 quote ^= 1;
2228 continue;
2229 }
2230 if (quote)
2231 continue;
2232 if (isdigit(*ptr)) {
2233 /* skip numbers */
2234 do {
2235 ptr++;
2236 /* Check for alpha chars like ULL */
2237 } while (isalnum(*ptr));
2238 if (!*ptr)
2239 break;
2240 /*
2241 * A number must have some kind of delimiter after
2242 * it, and we can ignore that too.
2243 */
2244 continue;
2245 }
2246 if (isalpha(*ptr) || *ptr == '_') {
2247 if (strncmp(map->enum_string, ptr, len) == 0 &&
2248 !isalnum(ptr[len]) && ptr[len] != '_') {
2249 ptr = enum_replace(ptr, map, len);
2250 /* Hmm, enum string smaller than value */
2251 if (WARN_ON_ONCE(!ptr))
2252 return;
2253 /*
2254 * No need to decrement here, as enum_replace()
2255 * returns the pointer to the character passed
2256 * the enum, and two enums can not be placed
2257 * back to back without something in between.
2258 * We can skip that something in between.
2259 */
2260 continue;
2261 }
2262 skip_more:
2263 do {
2264 ptr++;
2265 } while (isalnum(*ptr) || *ptr == '_');
2266 if (!*ptr)
2267 break;
2268 /*
2269 * If what comes after this variable is a '.' or
2270 * '->' then we can continue to ignore that string.
2271 */
2272 if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2273 ptr += *ptr == '.' ? 1 : 2;
2274 if (!*ptr)
2275 break;
2276 goto skip_more;
2277 }
2278 /*
2279 * Once again, we can skip the delimiter that came
2280 * after the string.
2281 */
2282 continue;
2283 }
2284 }
2285}
2286
2287void trace_event_enum_update(struct trace_enum_map **map, int len)
2288{
2289 struct trace_event_call *call, *p;
2290 const char *last_system = NULL;
2291 int last_i;
2292 int i;
2293
2294 down_write(&trace_event_sem);
2295 list_for_each_entry_safe(call, p, &ftrace_events, list) {
2296 /* events are usually grouped together with systems */
2297 if (!last_system || call->class->system != last_system) {
2298 last_i = 0;
2299 last_system = call->class->system;
2300 }
2301
2302 for (i = last_i; i < len; i++) {
2303 if (call->class->system == map[i]->system) {
2304 /* Save the first system if need be */
2305 if (!last_i)
2306 last_i = i;
2307 update_event_printk(call, map[i]);
2308 }
2309 }
2310 }
2311 up_write(&trace_event_sem);
2312}
2313
2314static struct trace_event_file *
2315trace_create_new_event(struct trace_event_call *call,
2316 struct trace_array *tr)
2317{
2318 struct trace_event_file *file;
2319
2320 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2321 if (!file)
2322 return NULL;
2323
2324 file->event_call = call;
2325 file->tr = tr;
2326 atomic_set(&file->sm_ref, 0);
2327 atomic_set(&file->tm_ref, 0);
2328 INIT_LIST_HEAD(&file->triggers);
2329 list_add(&file->list, &tr->events);
2330
2331 return file;
2332}
2333
2334/* Add an event to a trace directory */
2335static int
2336__trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2337{
2338 struct trace_event_file *file;
2339
2340 file = trace_create_new_event(call, tr);
2341 if (!file)
2342 return -ENOMEM;
2343
2344 return event_create_dir(tr->event_dir, file);
2345}
2346
2347/*
2348 * Just create a decriptor for early init. A descriptor is required
2349 * for enabling events at boot. We want to enable events before
2350 * the filesystem is initialized.
2351 */
2352static __init int
2353__trace_early_add_new_event(struct trace_event_call *call,
2354 struct trace_array *tr)
2355{
2356 struct trace_event_file *file;
2357
2358 file = trace_create_new_event(call, tr);
2359 if (!file)
2360 return -ENOMEM;
2361
2362 return 0;
2363}
2364
2365struct ftrace_module_file_ops;
2366static void __add_event_to_tracers(struct trace_event_call *call);
2367
2368/* Add an additional event_call dynamically */
2369int trace_add_event_call(struct trace_event_call *call)
2370{
2371 int ret;
2372 mutex_lock(&trace_types_lock);
2373 mutex_lock(&event_mutex);
2374
2375 ret = __register_event(call, NULL);
2376 if (ret >= 0)
2377 __add_event_to_tracers(call);
2378
2379 mutex_unlock(&event_mutex);
2380 mutex_unlock(&trace_types_lock);
2381 return ret;
2382}
2383
2384/*
2385 * Must be called under locking of trace_types_lock, event_mutex and
2386 * trace_event_sem.
2387 */
2388static void __trace_remove_event_call(struct trace_event_call *call)
2389{
2390 event_remove(call);
2391 trace_destroy_fields(call);
2392 free_event_filter(call->filter);
2393 call->filter = NULL;
2394}
2395
2396static int probe_remove_event_call(struct trace_event_call *call)
2397{
2398 struct trace_array *tr;
2399 struct trace_event_file *file;
2400
2401#ifdef CONFIG_PERF_EVENTS
2402 if (call->perf_refcount)
2403 return -EBUSY;
2404#endif
2405 do_for_each_event_file(tr, file) {
2406 if (file->event_call != call)
2407 continue;
2408 /*
2409 * We can't rely on ftrace_event_enable_disable(enable => 0)
2410 * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
2411 * TRACE_REG_UNREGISTER.
2412 */
2413 if (file->flags & EVENT_FILE_FL_ENABLED)
2414 return -EBUSY;
2415 /*
2416 * The do_for_each_event_file_safe() is
2417 * a double loop. After finding the call for this
2418 * trace_array, we use break to jump to the next
2419 * trace_array.
2420 */
2421 break;
2422 } while_for_each_event_file();
2423
2424 __trace_remove_event_call(call);
2425
2426 return 0;
2427}
2428
2429/* Remove an event_call */
2430int trace_remove_event_call(struct trace_event_call *call)
2431{
2432 int ret;
2433
2434 mutex_lock(&trace_types_lock);
2435 mutex_lock(&event_mutex);
2436 down_write(&trace_event_sem);
2437 ret = probe_remove_event_call(call);
2438 up_write(&trace_event_sem);
2439 mutex_unlock(&event_mutex);
2440 mutex_unlock(&trace_types_lock);
2441
2442 return ret;
2443}
2444
2445#define for_each_event(event, start, end) \
2446 for (event = start; \
2447 (unsigned long)event < (unsigned long)end; \
2448 event++)
2449
2450#ifdef CONFIG_MODULES
2451
2452static void trace_module_add_events(struct module *mod)
2453{
2454 struct trace_event_call **call, **start, **end;
2455
2456 if (!mod->num_trace_events)
2457 return;
2458
2459 /* Don't add infrastructure for mods without tracepoints */
2460 if (trace_module_has_bad_taint(mod)) {
2461 pr_err("%s: module has bad taint, not creating trace events\n",
2462 mod->name);
2463 return;
2464 }
2465
2466 start = mod->trace_events;
2467 end = mod->trace_events + mod->num_trace_events;
2468
2469 for_each_event(call, start, end) {
2470 __register_event(*call, mod);
2471 __add_event_to_tracers(*call);
2472 }
2473}
2474
2475static void trace_module_remove_events(struct module *mod)
2476{
2477 struct trace_event_call *call, *p;
2478 bool clear_trace = false;
2479
2480 down_write(&trace_event_sem);
2481 list_for_each_entry_safe(call, p, &ftrace_events, list) {
2482 if (call->mod == mod) {
2483 if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
2484 clear_trace = true;
2485 __trace_remove_event_call(call);
2486 }
2487 }
2488 up_write(&trace_event_sem);
2489
2490 /*
2491 * It is safest to reset the ring buffer if the module being unloaded
2492 * registered any events that were used. The only worry is if
2493 * a new module gets loaded, and takes on the same id as the events
2494 * of this module. When printing out the buffer, traced events left
2495 * over from this module may be passed to the new module events and
2496 * unexpected results may occur.
2497 */
2498 if (clear_trace)
2499 tracing_reset_all_online_cpus();
2500}
2501
2502static int trace_module_notify(struct notifier_block *self,
2503 unsigned long val, void *data)
2504{
2505 struct module *mod = data;
2506
2507 mutex_lock(&trace_types_lock);
2508 mutex_lock(&event_mutex);
2509 switch (val) {
2510 case MODULE_STATE_COMING:
2511 trace_module_add_events(mod);
2512 break;
2513 case MODULE_STATE_GOING:
2514 trace_module_remove_events(mod);
2515 break;
2516 }
2517 mutex_unlock(&event_mutex);
2518 mutex_unlock(&trace_types_lock);
2519
2520 return 0;
2521}
2522
2523static struct notifier_block trace_module_nb = {
2524 .notifier_call = trace_module_notify,
2525 .priority = 1, /* higher than trace.c module notify */
2526};
2527#endif /* CONFIG_MODULES */
2528
2529/* Create a new event directory structure for a trace directory. */
2530static void
2531__trace_add_event_dirs(struct trace_array *tr)
2532{
2533 struct trace_event_call *call;
2534 int ret;
2535
2536 list_for_each_entry(call, &ftrace_events, list) {
2537 ret = __trace_add_new_event(call, tr);
2538 if (ret < 0)
2539 pr_warn("Could not create directory for event %s\n",
2540 trace_event_name(call));
2541 }
2542}
2543
2544struct trace_event_file *
2545find_event_file(struct trace_array *tr, const char *system, const char *event)
2546{
2547 struct trace_event_file *file;
2548 struct trace_event_call *call;
2549 const char *name;
2550
2551 list_for_each_entry(file, &tr->events, list) {
2552
2553 call = file->event_call;
2554 name = trace_event_name(call);
2555
2556 if (!name || !call->class || !call->class->reg)
2557 continue;
2558
2559 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
2560 continue;
2561
2562 if (strcmp(event, name) == 0 &&
2563 strcmp(system, call->class->system) == 0)
2564 return file;
2565 }
2566 return NULL;
2567}
2568
2569#ifdef CONFIG_DYNAMIC_FTRACE
2570
2571/* Avoid typos */
2572#define ENABLE_EVENT_STR "enable_event"
2573#define DISABLE_EVENT_STR "disable_event"
2574
2575struct event_probe_data {
2576 struct trace_event_file *file;
2577 unsigned long count;
2578 int ref;
2579 bool enable;
2580};
2581
2582static void
2583event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
2584{
2585 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2586 struct event_probe_data *data = *pdata;
2587
2588 if (!data)
2589 return;
2590
2591 if (data->enable)
2592 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2593 else
2594 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2595}
2596
2597static void
2598event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
2599{
2600 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2601 struct event_probe_data *data = *pdata;
2602
2603 if (!data)
2604 return;
2605
2606 if (!data->count)
2607 return;
2608
2609 /* Skip if the event is in a state we want to switch to */
2610 if (data->enable == !(data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
2611 return;
2612
2613 if (data->count != -1)
2614 (data->count)--;
2615
2616 event_enable_probe(ip, parent_ip, _data);
2617}
2618
2619static int
2620event_enable_print(struct seq_file *m, unsigned long ip,
2621 struct ftrace_probe_ops *ops, void *_data)
2622{
2623 struct event_probe_data *data = _data;
2624
2625 seq_printf(m, "%ps:", (void *)ip);
2626
2627 seq_printf(m, "%s:%s:%s",
2628 data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
2629 data->file->event_call->class->system,
2630 trace_event_name(data->file->event_call));
2631
2632 if (data->count == -1)
2633 seq_puts(m, ":unlimited\n");
2634 else
2635 seq_printf(m, ":count=%ld\n", data->count);
2636
2637 return 0;
2638}
2639
2640static int
2641event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
2642 void **_data)
2643{
2644 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2645 struct event_probe_data *data = *pdata;
2646
2647 data->ref++;
2648 return 0;
2649}
2650
2651static void
2652event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
2653 void **_data)
2654{
2655 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2656 struct event_probe_data *data = *pdata;
2657
2658 if (WARN_ON_ONCE(data->ref <= 0))
2659 return;
2660
2661 data->ref--;
2662 if (!data->ref) {
2663 /* Remove the SOFT_MODE flag */
2664 __ftrace_event_enable_disable(data->file, 0, 1);
2665 module_put(data->file->event_call->mod);
2666 kfree(data);
2667 }
2668 *pdata = NULL;
2669}
2670
2671static struct ftrace_probe_ops event_enable_probe_ops = {
2672 .func = event_enable_probe,
2673 .print = event_enable_print,
2674 .init = event_enable_init,
2675 .free = event_enable_free,
2676};
2677
2678static struct ftrace_probe_ops event_enable_count_probe_ops = {
2679 .func = event_enable_count_probe,
2680 .print = event_enable_print,
2681 .init = event_enable_init,
2682 .free = event_enable_free,
2683};
2684
2685static struct ftrace_probe_ops event_disable_probe_ops = {
2686 .func = event_enable_probe,
2687 .print = event_enable_print,
2688 .init = event_enable_init,
2689 .free = event_enable_free,
2690};
2691
2692static struct ftrace_probe_ops event_disable_count_probe_ops = {
2693 .func = event_enable_count_probe,
2694 .print = event_enable_print,
2695 .init = event_enable_init,
2696 .free = event_enable_free,
2697};
2698
2699static int
2700event_enable_func(struct ftrace_hash *hash,
2701 char *glob, char *cmd, char *param, int enabled)
2702{
2703 struct trace_array *tr = top_trace_array();
2704 struct trace_event_file *file;
2705 struct ftrace_probe_ops *ops;
2706 struct event_probe_data *data;
2707 const char *system;
2708 const char *event;
2709 char *number;
2710 bool enable;
2711 int ret;
2712
2713 if (!tr)
2714 return -ENODEV;
2715
2716 /* hash funcs only work with set_ftrace_filter */
2717 if (!enabled || !param)
2718 return -EINVAL;
2719
2720 system = strsep(¶m, ":");
2721 if (!param)
2722 return -EINVAL;
2723
2724 event = strsep(¶m, ":");
2725
2726 mutex_lock(&event_mutex);
2727
2728 ret = -EINVAL;
2729 file = find_event_file(tr, system, event);
2730 if (!file)
2731 goto out;
2732
2733 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2734
2735 if (enable)
2736 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2737 else
2738 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2739
2740 if (glob[0] == '!') {
2741 unregister_ftrace_function_probe_func(glob+1, ops);
2742 ret = 0;
2743 goto out;
2744 }
2745
2746 ret = -ENOMEM;
2747 data = kzalloc(sizeof(*data), GFP_KERNEL);
2748 if (!data)
2749 goto out;
2750
2751 data->enable = enable;
2752 data->count = -1;
2753 data->file = file;
2754
2755 if (!param)
2756 goto out_reg;
2757
2758 number = strsep(¶m, ":");
2759
2760 ret = -EINVAL;
2761 if (!strlen(number))
2762 goto out_free;
2763
2764 /*
2765 * We use the callback data field (which is a pointer)
2766 * as our counter.
2767 */
2768 ret = kstrtoul(number, 0, &data->count);
2769 if (ret)
2770 goto out_free;
2771
2772 out_reg:
2773 /* Don't let event modules unload while probe registered */
2774 ret = try_module_get(file->event_call->mod);
2775 if (!ret) {
2776 ret = -EBUSY;
2777 goto out_free;
2778 }
2779
2780 ret = __ftrace_event_enable_disable(file, 1, 1);
2781 if (ret < 0)
2782 goto out_put;
2783 ret = register_ftrace_function_probe(glob, ops, data);
2784 /*
2785 * The above returns on success the # of functions enabled,
2786 * but if it didn't find any functions it returns zero.
2787 * Consider no functions a failure too.
2788 */
2789 if (!ret) {
2790 ret = -ENOENT;
2791 goto out_disable;
2792 } else if (ret < 0)
2793 goto out_disable;
2794 /* Just return zero, not the number of enabled functions */
2795 ret = 0;
2796 out:
2797 mutex_unlock(&event_mutex);
2798 return ret;
2799
2800 out_disable:
2801 __ftrace_event_enable_disable(file, 0, 1);
2802 out_put:
2803 module_put(file->event_call->mod);
2804 out_free:
2805 kfree(data);
2806 goto out;
2807}
2808
2809static struct ftrace_func_command event_enable_cmd = {
2810 .name = ENABLE_EVENT_STR,
2811 .func = event_enable_func,
2812};
2813
2814static struct ftrace_func_command event_disable_cmd = {
2815 .name = DISABLE_EVENT_STR,
2816 .func = event_enable_func,
2817};
2818
2819static __init int register_event_cmds(void)
2820{
2821 int ret;
2822
2823 ret = register_ftrace_command(&event_enable_cmd);
2824 if (WARN_ON(ret < 0))
2825 return ret;
2826 ret = register_ftrace_command(&event_disable_cmd);
2827 if (WARN_ON(ret < 0))
2828 unregister_ftrace_command(&event_enable_cmd);
2829 return ret;
2830}
2831#else
2832static inline int register_event_cmds(void) { return 0; }
2833#endif /* CONFIG_DYNAMIC_FTRACE */
2834
2835/*
2836 * The top level array has already had its trace_event_file
2837 * descriptors created in order to allow for early events to
2838 * be recorded. This function is called after the tracefs has been
2839 * initialized, and we now have to create the files associated
2840 * to the events.
2841 */
2842static __init void
2843__trace_early_add_event_dirs(struct trace_array *tr)
2844{
2845 struct trace_event_file *file;
2846 int ret;
2847
2848
2849 list_for_each_entry(file, &tr->events, list) {
2850 ret = event_create_dir(tr->event_dir, file);
2851 if (ret < 0)
2852 pr_warn("Could not create directory for event %s\n",
2853 trace_event_name(file->event_call));
2854 }
2855}
2856
2857/*
2858 * For early boot up, the top trace array requires to have
2859 * a list of events that can be enabled. This must be done before
2860 * the filesystem is set up in order to allow events to be traced
2861 * early.
2862 */
2863static __init void
2864__trace_early_add_events(struct trace_array *tr)
2865{
2866 struct trace_event_call *call;
2867 int ret;
2868
2869 list_for_each_entry(call, &ftrace_events, list) {
2870 /* Early boot up should not have any modules loaded */
2871 if (WARN_ON_ONCE(call->mod))
2872 continue;
2873
2874 ret = __trace_early_add_new_event(call, tr);
2875 if (ret < 0)
2876 pr_warn("Could not create early event %s\n",
2877 trace_event_name(call));
2878 }
2879}
2880
2881/* Remove the event directory structure for a trace directory. */
2882static void
2883__trace_remove_event_dirs(struct trace_array *tr)
2884{
2885 struct trace_event_file *file, *next;
2886
2887 list_for_each_entry_safe(file, next, &tr->events, list)
2888 remove_event_file_dir(file);
2889}
2890
2891static void __add_event_to_tracers(struct trace_event_call *call)
2892{
2893 struct trace_array *tr;
2894
2895 list_for_each_entry(tr, &ftrace_trace_arrays, list)
2896 __trace_add_new_event(call, tr);
2897}
2898
2899extern struct trace_event_call *__start_ftrace_events[];
2900extern struct trace_event_call *__stop_ftrace_events[];
2901
2902static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2903
2904static __init int setup_trace_event(char *str)
2905{
2906 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2907 ring_buffer_expanded = true;
2908 tracing_selftest_disabled = true;
2909
2910 return 1;
2911}
2912__setup("trace_event=", setup_trace_event);
2913
2914/* Expects to have event_mutex held when called */
2915static int
2916create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2917{
2918 struct dentry *d_events;
2919 struct dentry *entry;
2920
2921 entry = tracefs_create_file("set_event", 0644, parent,
2922 tr, &ftrace_set_event_fops);
2923 if (!entry) {
2924 pr_warn("Could not create tracefs 'set_event' entry\n");
2925 return -ENOMEM;
2926 }
2927
2928 d_events = tracefs_create_dir("events", parent);
2929 if (!d_events) {
2930 pr_warn("Could not create tracefs 'events' directory\n");
2931 return -ENOMEM;
2932 }
2933
2934 entry = tracefs_create_file("set_event_pid", 0644, parent,
2935 tr, &ftrace_set_event_pid_fops);
2936
2937 /* ring buffer internal formats */
2938 trace_create_file("header_page", 0444, d_events,
2939 ring_buffer_print_page_header,
2940 &ftrace_show_header_fops);
2941
2942 trace_create_file("header_event", 0444, d_events,
2943 ring_buffer_print_entry_header,
2944 &ftrace_show_header_fops);
2945
2946 trace_create_file("enable", 0644, d_events,
2947 tr, &ftrace_tr_enable_fops);
2948
2949 tr->event_dir = d_events;
2950
2951 return 0;
2952}
2953
2954/**
2955 * event_trace_add_tracer - add a instance of a trace_array to events
2956 * @parent: The parent dentry to place the files/directories for events in
2957 * @tr: The trace array associated with these events
2958 *
2959 * When a new instance is created, it needs to set up its events
2960 * directory, as well as other files associated with events. It also
2961 * creates the event hierachry in the @parent/events directory.
2962 *
2963 * Returns 0 on success.
2964 */
2965int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2966{
2967 int ret;
2968
2969 mutex_lock(&event_mutex);
2970
2971 ret = create_event_toplevel_files(parent, tr);
2972 if (ret)
2973 goto out_unlock;
2974
2975 down_write(&trace_event_sem);
2976 __trace_add_event_dirs(tr);
2977 up_write(&trace_event_sem);
2978
2979 out_unlock:
2980 mutex_unlock(&event_mutex);
2981
2982 return ret;
2983}
2984
2985/*
2986 * The top trace array already had its file descriptors created.
2987 * Now the files themselves need to be created.
2988 */
2989static __init int
2990early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2991{
2992 int ret;
2993
2994 mutex_lock(&event_mutex);
2995
2996 ret = create_event_toplevel_files(parent, tr);
2997 if (ret)
2998 goto out_unlock;
2999
3000 down_write(&trace_event_sem);
3001 __trace_early_add_event_dirs(tr);
3002 up_write(&trace_event_sem);
3003
3004 out_unlock:
3005 mutex_unlock(&event_mutex);
3006
3007 return ret;
3008}
3009
3010int event_trace_del_tracer(struct trace_array *tr)
3011{
3012 mutex_lock(&event_mutex);
3013
3014 /* Disable any event triggers and associated soft-disabled events */
3015 clear_event_triggers(tr);
3016
3017 /* Clear the pid list */
3018 __ftrace_clear_event_pids(tr);
3019
3020 /* Disable any running events */
3021 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3022
3023 /* Access to events are within rcu_read_lock_sched() */
3024 synchronize_sched();
3025
3026 down_write(&trace_event_sem);
3027 __trace_remove_event_dirs(tr);
3028 tracefs_remove_recursive(tr->event_dir);
3029 up_write(&trace_event_sem);
3030
3031 tr->event_dir = NULL;
3032
3033 mutex_unlock(&event_mutex);
3034
3035 return 0;
3036}
3037
3038static __init int event_trace_memsetup(void)
3039{
3040 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3041 file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3042 return 0;
3043}
3044
3045static __init void
3046early_enable_events(struct trace_array *tr, bool disable_first)
3047{
3048 char *buf = bootup_event_buf;
3049 char *token;
3050 int ret;
3051
3052 while (true) {
3053 token = strsep(&buf, ",");
3054
3055 if (!token)
3056 break;
3057
3058 if (*token) {
3059 /* Restarting syscalls requires that we stop them first */
3060 if (disable_first)
3061 ftrace_set_clr_event(tr, token, 0);
3062
3063 ret = ftrace_set_clr_event(tr, token, 1);
3064 if (ret)
3065 pr_warn("Failed to enable trace event: %s\n", token);
3066 }
3067
3068 /* Put back the comma to allow this to be called again */
3069 if (buf)
3070 *(buf - 1) = ',';
3071 }
3072}
3073
3074static __init int event_trace_enable(void)
3075{
3076 struct trace_array *tr = top_trace_array();
3077 struct trace_event_call **iter, *call;
3078 int ret;
3079
3080 if (!tr)
3081 return -ENODEV;
3082
3083 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3084
3085 call = *iter;
3086 ret = event_init(call);
3087 if (!ret)
3088 list_add(&call->list, &ftrace_events);
3089 }
3090
3091 /*
3092 * We need the top trace array to have a working set of trace
3093 * points at early init, before the debug files and directories
3094 * are created. Create the file entries now, and attach them
3095 * to the actual file dentries later.
3096 */
3097 __trace_early_add_events(tr);
3098
3099 early_enable_events(tr, false);
3100
3101 trace_printk_start_comm();
3102
3103 register_event_cmds();
3104
3105 register_trigger_cmds();
3106
3107 return 0;
3108}
3109
3110/*
3111 * event_trace_enable() is called from trace_event_init() first to
3112 * initialize events and perhaps start any events that are on the
3113 * command line. Unfortunately, there are some events that will not
3114 * start this early, like the system call tracepoints that need
3115 * to set the TIF_SYSCALL_TRACEPOINT flag of pid 1. But event_trace_enable()
3116 * is called before pid 1 starts, and this flag is never set, making
3117 * the syscall tracepoint never get reached, but the event is enabled
3118 * regardless (and not doing anything).
3119 */
3120static __init int event_trace_enable_again(void)
3121{
3122 struct trace_array *tr;
3123
3124 tr = top_trace_array();
3125 if (!tr)
3126 return -ENODEV;
3127
3128 early_enable_events(tr, true);
3129
3130 return 0;
3131}
3132
3133early_initcall(event_trace_enable_again);
3134
3135static __init int event_trace_init(void)
3136{
3137 struct trace_array *tr;
3138 struct dentry *d_tracer;
3139 struct dentry *entry;
3140 int ret;
3141
3142 tr = top_trace_array();
3143 if (!tr)
3144 return -ENODEV;
3145
3146 d_tracer = tracing_init_dentry();
3147 if (IS_ERR(d_tracer))
3148 return 0;
3149
3150 entry = tracefs_create_file("available_events", 0444, d_tracer,
3151 tr, &ftrace_avail_fops);
3152 if (!entry)
3153 pr_warn("Could not create tracefs 'available_events' entry\n");
3154
3155 if (trace_define_generic_fields())
3156 pr_warn("tracing: Failed to allocated generic fields");
3157
3158 if (trace_define_common_fields())
3159 pr_warn("tracing: Failed to allocate common fields");
3160
3161 ret = early_event_add_tracer(d_tracer, tr);
3162 if (ret)
3163 return ret;
3164
3165#ifdef CONFIG_MODULES
3166 ret = register_module_notifier(&trace_module_nb);
3167 if (ret)
3168 pr_warn("Failed to register trace events module notifier\n");
3169#endif
3170 return 0;
3171}
3172
3173void __init trace_event_init(void)
3174{
3175 event_trace_memsetup();
3176 init_ftrace_syscalls();
3177 event_trace_enable();
3178}
3179
3180fs_initcall(event_trace_init);
3181
3182#ifdef CONFIG_FTRACE_STARTUP_TEST
3183
3184static DEFINE_SPINLOCK(test_spinlock);
3185static DEFINE_SPINLOCK(test_spinlock_irq);
3186static DEFINE_MUTEX(test_mutex);
3187
3188static __init void test_work(struct work_struct *dummy)
3189{
3190 spin_lock(&test_spinlock);
3191 spin_lock_irq(&test_spinlock_irq);
3192 udelay(1);
3193 spin_unlock_irq(&test_spinlock_irq);
3194 spin_unlock(&test_spinlock);
3195
3196 mutex_lock(&test_mutex);
3197 msleep(1);
3198 mutex_unlock(&test_mutex);
3199}
3200
3201static __init int event_test_thread(void *unused)
3202{
3203 void *test_malloc;
3204
3205 test_malloc = kmalloc(1234, GFP_KERNEL);
3206 if (!test_malloc)
3207 pr_info("failed to kmalloc\n");
3208
3209 schedule_on_each_cpu(test_work);
3210
3211 kfree(test_malloc);
3212
3213 set_current_state(TASK_INTERRUPTIBLE);
3214 while (!kthread_should_stop()) {
3215 schedule();
3216 set_current_state(TASK_INTERRUPTIBLE);
3217 }
3218 __set_current_state(TASK_RUNNING);
3219
3220 return 0;
3221}
3222
3223/*
3224 * Do various things that may trigger events.
3225 */
3226static __init void event_test_stuff(void)
3227{
3228 struct task_struct *test_thread;
3229
3230 test_thread = kthread_run(event_test_thread, NULL, "test-events");
3231 msleep(1);
3232 kthread_stop(test_thread);
3233}
3234
3235/*
3236 * For every trace event defined, we will test each trace point separately,
3237 * and then by groups, and finally all trace points.
3238 */
3239static __init void event_trace_self_tests(void)
3240{
3241 struct trace_subsystem_dir *dir;
3242 struct trace_event_file *file;
3243 struct trace_event_call *call;
3244 struct event_subsystem *system;
3245 struct trace_array *tr;
3246 int ret;
3247
3248 tr = top_trace_array();
3249 if (!tr)
3250 return;
3251
3252 pr_info("Running tests on trace events:\n");
3253
3254 list_for_each_entry(file, &tr->events, list) {
3255
3256 call = file->event_call;
3257
3258 /* Only test those that have a probe */
3259 if (!call->class || !call->class->probe)
3260 continue;
3261
3262/*
3263 * Testing syscall events here is pretty useless, but
3264 * we still do it if configured. But this is time consuming.
3265 * What we really need is a user thread to perform the
3266 * syscalls as we test.
3267 */
3268#ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
3269 if (call->class->system &&
3270 strcmp(call->class->system, "syscalls") == 0)
3271 continue;
3272#endif
3273
3274 pr_info("Testing event %s: ", trace_event_name(call));
3275
3276 /*
3277 * If an event is already enabled, someone is using
3278 * it and the self test should not be on.
3279 */
3280 if (file->flags & EVENT_FILE_FL_ENABLED) {
3281 pr_warn("Enabled event during self test!\n");
3282 WARN_ON_ONCE(1);
3283 continue;
3284 }
3285
3286 ftrace_event_enable_disable(file, 1);
3287 event_test_stuff();
3288 ftrace_event_enable_disable(file, 0);
3289
3290 pr_cont("OK\n");
3291 }
3292
3293 /* Now test at the sub system level */
3294
3295 pr_info("Running tests on trace event systems:\n");
3296
3297 list_for_each_entry(dir, &tr->systems, list) {
3298
3299 system = dir->subsystem;
3300
3301 /* the ftrace system is special, skip it */
3302 if (strcmp(system->name, "ftrace") == 0)
3303 continue;
3304
3305 pr_info("Testing event system %s: ", system->name);
3306
3307 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
3308 if (WARN_ON_ONCE(ret)) {
3309 pr_warn("error enabling system %s\n",
3310 system->name);
3311 continue;
3312 }
3313
3314 event_test_stuff();
3315
3316 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
3317 if (WARN_ON_ONCE(ret)) {
3318 pr_warn("error disabling system %s\n",
3319 system->name);
3320 continue;
3321 }
3322
3323 pr_cont("OK\n");
3324 }
3325
3326 /* Test with all events enabled */
3327
3328 pr_info("Running tests on all trace events:\n");
3329 pr_info("Testing all events: ");
3330
3331 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
3332 if (WARN_ON_ONCE(ret)) {
3333 pr_warn("error enabling all events\n");
3334 return;
3335 }
3336
3337 event_test_stuff();
3338
3339 /* reset sysname */
3340 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
3341 if (WARN_ON_ONCE(ret)) {
3342 pr_warn("error disabling all events\n");
3343 return;
3344 }
3345
3346 pr_cont("OK\n");
3347}
3348
3349#ifdef CONFIG_FUNCTION_TRACER
3350
3351static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
3352
3353static struct trace_array *event_tr;
3354
3355static void __init
3356function_test_events_call(unsigned long ip, unsigned long parent_ip,
3357 struct ftrace_ops *op, struct pt_regs *pt_regs)
3358{
3359 struct ring_buffer_event *event;
3360 struct ring_buffer *buffer;
3361 struct ftrace_entry *entry;
3362 unsigned long flags;
3363 long disabled;
3364 int cpu;
3365 int pc;
3366
3367 pc = preempt_count();
3368 preempt_disable_notrace();
3369 cpu = raw_smp_processor_id();
3370 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
3371
3372 if (disabled != 1)
3373 goto out;
3374
3375 local_save_flags(flags);
3376
3377 event = trace_current_buffer_lock_reserve(&buffer,
3378 TRACE_FN, sizeof(*entry),
3379 flags, pc);
3380 if (!event)
3381 goto out;
3382 entry = ring_buffer_event_data(event);
3383 entry->ip = ip;
3384 entry->parent_ip = parent_ip;
3385
3386 trace_buffer_unlock_commit(event_tr, buffer, event, flags, pc);
3387
3388 out:
3389 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
3390 preempt_enable_notrace();
3391}
3392
3393static struct ftrace_ops trace_ops __initdata =
3394{
3395 .func = function_test_events_call,
3396 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
3397};
3398
3399static __init void event_trace_self_test_with_function(void)
3400{
3401 int ret;
3402 event_tr = top_trace_array();
3403 if (WARN_ON(!event_tr))
3404 return;
3405 ret = register_ftrace_function(&trace_ops);
3406 if (WARN_ON(ret < 0)) {
3407 pr_info("Failed to enable function tracer for event tests\n");
3408 return;
3409 }
3410 pr_info("Running tests again, along with the function tracer\n");
3411 event_trace_self_tests();
3412 unregister_ftrace_function(&trace_ops);
3413}
3414#else
3415static __init void event_trace_self_test_with_function(void)
3416{
3417}
3418#endif
3419
3420static __init int event_trace_self_tests_init(void)
3421{
3422 if (!tracing_selftest_disabled) {
3423 event_trace_self_tests();
3424 event_trace_self_test_with_function();
3425 }
3426
3427 return 0;
3428}
3429
3430late_initcall(event_trace_self_tests_init);
3431
3432#endif
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * event tracer
4 *
5 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
6 *
7 * - Added format output of fields of the trace point.
8 * This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
9 *
10 */
11
12#define pr_fmt(fmt) fmt
13
14#include <linux/workqueue.h>
15#include <linux/security.h>
16#include <linux/spinlock.h>
17#include <linux/kthread.h>
18#include <linux/tracefs.h>
19#include <linux/uaccess.h>
20#include <linux/module.h>
21#include <linux/ctype.h>
22#include <linux/sort.h>
23#include <linux/slab.h>
24#include <linux/delay.h>
25
26#include <trace/events/sched.h>
27#include <trace/syscall.h>
28
29#include <asm/setup.h>
30
31#include "trace_output.h"
32
33#undef TRACE_SYSTEM
34#define TRACE_SYSTEM "TRACE_SYSTEM"
35
36DEFINE_MUTEX(event_mutex);
37
38LIST_HEAD(ftrace_events);
39static LIST_HEAD(ftrace_generic_fields);
40static LIST_HEAD(ftrace_common_fields);
41static bool eventdir_initialized;
42
43static LIST_HEAD(module_strings);
44
45struct module_string {
46 struct list_head next;
47 struct module *module;
48 char *str;
49};
50
51#define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
52
53static struct kmem_cache *field_cachep;
54static struct kmem_cache *file_cachep;
55
56static inline int system_refcount(struct event_subsystem *system)
57{
58 return system->ref_count;
59}
60
61static int system_refcount_inc(struct event_subsystem *system)
62{
63 return system->ref_count++;
64}
65
66static int system_refcount_dec(struct event_subsystem *system)
67{
68 return --system->ref_count;
69}
70
71/* Double loops, do not use break, only goto's work */
72#define do_for_each_event_file(tr, file) \
73 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
74 list_for_each_entry(file, &tr->events, list)
75
76#define do_for_each_event_file_safe(tr, file) \
77 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
78 struct trace_event_file *___n; \
79 list_for_each_entry_safe(file, ___n, &tr->events, list)
80
81#define while_for_each_event_file() \
82 }
83
84static struct ftrace_event_field *
85__find_event_field(struct list_head *head, char *name)
86{
87 struct ftrace_event_field *field;
88
89 list_for_each_entry(field, head, link) {
90 if (!strcmp(field->name, name))
91 return field;
92 }
93
94 return NULL;
95}
96
97struct ftrace_event_field *
98trace_find_event_field(struct trace_event_call *call, char *name)
99{
100 struct ftrace_event_field *field;
101 struct list_head *head;
102
103 head = trace_get_fields(call);
104 field = __find_event_field(head, name);
105 if (field)
106 return field;
107
108 field = __find_event_field(&ftrace_generic_fields, name);
109 if (field)
110 return field;
111
112 return __find_event_field(&ftrace_common_fields, name);
113}
114
115static int __trace_define_field(struct list_head *head, const char *type,
116 const char *name, int offset, int size,
117 int is_signed, int filter_type, int len)
118{
119 struct ftrace_event_field *field;
120
121 field = kmem_cache_alloc(field_cachep, GFP_TRACE);
122 if (!field)
123 return -ENOMEM;
124
125 field->name = name;
126 field->type = type;
127
128 if (filter_type == FILTER_OTHER)
129 field->filter_type = filter_assign_type(type);
130 else
131 field->filter_type = filter_type;
132
133 field->offset = offset;
134 field->size = size;
135 field->is_signed = is_signed;
136 field->len = len;
137
138 list_add(&field->link, head);
139
140 return 0;
141}
142
143int trace_define_field(struct trace_event_call *call, const char *type,
144 const char *name, int offset, int size, int is_signed,
145 int filter_type)
146{
147 struct list_head *head;
148
149 if (WARN_ON(!call->class))
150 return 0;
151
152 head = trace_get_fields(call);
153 return __trace_define_field(head, type, name, offset, size,
154 is_signed, filter_type, 0);
155}
156EXPORT_SYMBOL_GPL(trace_define_field);
157
158static int trace_define_field_ext(struct trace_event_call *call, const char *type,
159 const char *name, int offset, int size, int is_signed,
160 int filter_type, int len)
161{
162 struct list_head *head;
163
164 if (WARN_ON(!call->class))
165 return 0;
166
167 head = trace_get_fields(call);
168 return __trace_define_field(head, type, name, offset, size,
169 is_signed, filter_type, len);
170}
171
172#define __generic_field(type, item, filter_type) \
173 ret = __trace_define_field(&ftrace_generic_fields, #type, \
174 #item, 0, 0, is_signed_type(type), \
175 filter_type, 0); \
176 if (ret) \
177 return ret;
178
179#define __common_field(type, item) \
180 ret = __trace_define_field(&ftrace_common_fields, #type, \
181 "common_" #item, \
182 offsetof(typeof(ent), item), \
183 sizeof(ent.item), \
184 is_signed_type(type), FILTER_OTHER, 0); \
185 if (ret) \
186 return ret;
187
188static int trace_define_generic_fields(void)
189{
190 int ret;
191
192 __generic_field(int, CPU, FILTER_CPU);
193 __generic_field(int, cpu, FILTER_CPU);
194 __generic_field(int, common_cpu, FILTER_CPU);
195 __generic_field(char *, COMM, FILTER_COMM);
196 __generic_field(char *, comm, FILTER_COMM);
197
198 return ret;
199}
200
201static int trace_define_common_fields(void)
202{
203 int ret;
204 struct trace_entry ent;
205
206 __common_field(unsigned short, type);
207 __common_field(unsigned char, flags);
208 /* Holds both preempt_count and migrate_disable */
209 __common_field(unsigned char, preempt_count);
210 __common_field(int, pid);
211
212 return ret;
213}
214
215static void trace_destroy_fields(struct trace_event_call *call)
216{
217 struct ftrace_event_field *field, *next;
218 struct list_head *head;
219
220 head = trace_get_fields(call);
221 list_for_each_entry_safe(field, next, head, link) {
222 list_del(&field->link);
223 kmem_cache_free(field_cachep, field);
224 }
225}
226
227/*
228 * run-time version of trace_event_get_offsets_<call>() that returns the last
229 * accessible offset of trace fields excluding __dynamic_array bytes
230 */
231int trace_event_get_offsets(struct trace_event_call *call)
232{
233 struct ftrace_event_field *tail;
234 struct list_head *head;
235
236 head = trace_get_fields(call);
237 /*
238 * head->next points to the last field with the largest offset,
239 * since it was added last by trace_define_field()
240 */
241 tail = list_first_entry(head, struct ftrace_event_field, link);
242 return tail->offset + tail->size;
243}
244
245/*
246 * Check if the referenced field is an array and return true,
247 * as arrays are OK to dereference.
248 */
249static bool test_field(const char *fmt, struct trace_event_call *call)
250{
251 struct trace_event_fields *field = call->class->fields_array;
252 const char *array_descriptor;
253 const char *p = fmt;
254 int len;
255
256 if (!(len = str_has_prefix(fmt, "REC->")))
257 return false;
258 fmt += len;
259 for (p = fmt; *p; p++) {
260 if (!isalnum(*p) && *p != '_')
261 break;
262 }
263 len = p - fmt;
264
265 for (; field->type; field++) {
266 if (strncmp(field->name, fmt, len) ||
267 field->name[len])
268 continue;
269 array_descriptor = strchr(field->type, '[');
270 /* This is an array and is OK to dereference. */
271 return array_descriptor != NULL;
272 }
273 return false;
274}
275
276/*
277 * Examine the print fmt of the event looking for unsafe dereference
278 * pointers using %p* that could be recorded in the trace event and
279 * much later referenced after the pointer was freed. Dereferencing
280 * pointers are OK, if it is dereferenced into the event itself.
281 */
282static void test_event_printk(struct trace_event_call *call)
283{
284 u64 dereference_flags = 0;
285 bool first = true;
286 const char *fmt, *c, *r, *a;
287 int parens = 0;
288 char in_quote = 0;
289 int start_arg = 0;
290 int arg = 0;
291 int i;
292
293 fmt = call->print_fmt;
294
295 if (!fmt)
296 return;
297
298 for (i = 0; fmt[i]; i++) {
299 switch (fmt[i]) {
300 case '\\':
301 i++;
302 if (!fmt[i])
303 return;
304 continue;
305 case '"':
306 case '\'':
307 /*
308 * The print fmt starts with a string that
309 * is processed first to find %p* usage,
310 * then after the first string, the print fmt
311 * contains arguments that are used to check
312 * if the dereferenced %p* usage is safe.
313 */
314 if (first) {
315 if (fmt[i] == '\'')
316 continue;
317 if (in_quote) {
318 arg = 0;
319 first = false;
320 /*
321 * If there was no %p* uses
322 * the fmt is OK.
323 */
324 if (!dereference_flags)
325 return;
326 }
327 }
328 if (in_quote) {
329 if (in_quote == fmt[i])
330 in_quote = 0;
331 } else {
332 in_quote = fmt[i];
333 }
334 continue;
335 case '%':
336 if (!first || !in_quote)
337 continue;
338 i++;
339 if (!fmt[i])
340 return;
341 switch (fmt[i]) {
342 case '%':
343 continue;
344 case 'p':
345 /* Find dereferencing fields */
346 switch (fmt[i + 1]) {
347 case 'B': case 'R': case 'r':
348 case 'b': case 'M': case 'm':
349 case 'I': case 'i': case 'E':
350 case 'U': case 'V': case 'N':
351 case 'a': case 'd': case 'D':
352 case 'g': case 't': case 'C':
353 case 'O': case 'f':
354 if (WARN_ONCE(arg == 63,
355 "Too many args for event: %s",
356 trace_event_name(call)))
357 return;
358 dereference_flags |= 1ULL << arg;
359 }
360 break;
361 default:
362 {
363 bool star = false;
364 int j;
365
366 /* Increment arg if %*s exists. */
367 for (j = 0; fmt[i + j]; j++) {
368 if (isdigit(fmt[i + j]) ||
369 fmt[i + j] == '.')
370 continue;
371 if (fmt[i + j] == '*') {
372 star = true;
373 continue;
374 }
375 if ((fmt[i + j] == 's') && star)
376 arg++;
377 break;
378 }
379 break;
380 } /* default */
381
382 } /* switch */
383 arg++;
384 continue;
385 case '(':
386 if (in_quote)
387 continue;
388 parens++;
389 continue;
390 case ')':
391 if (in_quote)
392 continue;
393 parens--;
394 if (WARN_ONCE(parens < 0,
395 "Paren mismatch for event: %s\narg='%s'\n%*s",
396 trace_event_name(call),
397 fmt + start_arg,
398 (i - start_arg) + 5, "^"))
399 return;
400 continue;
401 case ',':
402 if (in_quote || parens)
403 continue;
404 i++;
405 while (isspace(fmt[i]))
406 i++;
407 start_arg = i;
408 if (!(dereference_flags & (1ULL << arg)))
409 goto next_arg;
410
411 /* Find the REC-> in the argument */
412 c = strchr(fmt + i, ',');
413 r = strstr(fmt + i, "REC->");
414 if (r && (!c || r < c)) {
415 /*
416 * Addresses of events on the buffer,
417 * or an array on the buffer is
418 * OK to dereference.
419 * There's ways to fool this, but
420 * this is to catch common mistakes,
421 * not malicious code.
422 */
423 a = strchr(fmt + i, '&');
424 if ((a && (a < r)) || test_field(r, call))
425 dereference_flags &= ~(1ULL << arg);
426 } else if ((r = strstr(fmt + i, "__get_dynamic_array(")) &&
427 (!c || r < c)) {
428 dereference_flags &= ~(1ULL << arg);
429 } else if ((r = strstr(fmt + i, "__get_sockaddr(")) &&
430 (!c || r < c)) {
431 dereference_flags &= ~(1ULL << arg);
432 }
433
434 next_arg:
435 i--;
436 arg++;
437 }
438 }
439
440 /*
441 * If you triggered the below warning, the trace event reported
442 * uses an unsafe dereference pointer %p*. As the data stored
443 * at the trace event time may no longer exist when the trace
444 * event is printed, dereferencing to the original source is
445 * unsafe. The source of the dereference must be copied into the
446 * event itself, and the dereference must access the copy instead.
447 */
448 if (WARN_ON_ONCE(dereference_flags)) {
449 arg = 1;
450 while (!(dereference_flags & 1)) {
451 dereference_flags >>= 1;
452 arg++;
453 }
454 pr_warn("event %s has unsafe dereference of argument %d\n",
455 trace_event_name(call), arg);
456 pr_warn("print_fmt: %s\n", fmt);
457 }
458}
459
460int trace_event_raw_init(struct trace_event_call *call)
461{
462 int id;
463
464 id = register_trace_event(&call->event);
465 if (!id)
466 return -ENODEV;
467
468 test_event_printk(call);
469
470 return 0;
471}
472EXPORT_SYMBOL_GPL(trace_event_raw_init);
473
474bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
475{
476 struct trace_array *tr = trace_file->tr;
477 struct trace_array_cpu *data;
478 struct trace_pid_list *no_pid_list;
479 struct trace_pid_list *pid_list;
480
481 pid_list = rcu_dereference_raw(tr->filtered_pids);
482 no_pid_list = rcu_dereference_raw(tr->filtered_no_pids);
483
484 if (!pid_list && !no_pid_list)
485 return false;
486
487 data = this_cpu_ptr(tr->array_buffer.data);
488
489 return data->ignore_pid;
490}
491EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
492
493void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
494 struct trace_event_file *trace_file,
495 unsigned long len)
496{
497 struct trace_event_call *event_call = trace_file->event_call;
498
499 if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
500 trace_event_ignore_this_pid(trace_file))
501 return NULL;
502
503 /*
504 * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
505 * preemption (adding one to the preempt_count). Since we are
506 * interested in the preempt_count at the time the tracepoint was
507 * hit, we need to subtract one to offset the increment.
508 */
509 fbuffer->trace_ctx = tracing_gen_ctx_dec();
510 fbuffer->trace_file = trace_file;
511
512 fbuffer->event =
513 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
514 event_call->event.type, len,
515 fbuffer->trace_ctx);
516 if (!fbuffer->event)
517 return NULL;
518
519 fbuffer->regs = NULL;
520 fbuffer->entry = ring_buffer_event_data(fbuffer->event);
521 return fbuffer->entry;
522}
523EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
524
525int trace_event_reg(struct trace_event_call *call,
526 enum trace_reg type, void *data)
527{
528 struct trace_event_file *file = data;
529
530 WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
531 switch (type) {
532 case TRACE_REG_REGISTER:
533 return tracepoint_probe_register(call->tp,
534 call->class->probe,
535 file);
536 case TRACE_REG_UNREGISTER:
537 tracepoint_probe_unregister(call->tp,
538 call->class->probe,
539 file);
540 return 0;
541
542#ifdef CONFIG_PERF_EVENTS
543 case TRACE_REG_PERF_REGISTER:
544 return tracepoint_probe_register(call->tp,
545 call->class->perf_probe,
546 call);
547 case TRACE_REG_PERF_UNREGISTER:
548 tracepoint_probe_unregister(call->tp,
549 call->class->perf_probe,
550 call);
551 return 0;
552 case TRACE_REG_PERF_OPEN:
553 case TRACE_REG_PERF_CLOSE:
554 case TRACE_REG_PERF_ADD:
555 case TRACE_REG_PERF_DEL:
556 return 0;
557#endif
558 }
559 return 0;
560}
561EXPORT_SYMBOL_GPL(trace_event_reg);
562
563void trace_event_enable_cmd_record(bool enable)
564{
565 struct trace_event_file *file;
566 struct trace_array *tr;
567
568 lockdep_assert_held(&event_mutex);
569
570 do_for_each_event_file(tr, file) {
571
572 if (!(file->flags & EVENT_FILE_FL_ENABLED))
573 continue;
574
575 if (enable) {
576 tracing_start_cmdline_record();
577 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
578 } else {
579 tracing_stop_cmdline_record();
580 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
581 }
582 } while_for_each_event_file();
583}
584
585void trace_event_enable_tgid_record(bool enable)
586{
587 struct trace_event_file *file;
588 struct trace_array *tr;
589
590 lockdep_assert_held(&event_mutex);
591
592 do_for_each_event_file(tr, file) {
593 if (!(file->flags & EVENT_FILE_FL_ENABLED))
594 continue;
595
596 if (enable) {
597 tracing_start_tgid_record();
598 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
599 } else {
600 tracing_stop_tgid_record();
601 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
602 &file->flags);
603 }
604 } while_for_each_event_file();
605}
606
607static int __ftrace_event_enable_disable(struct trace_event_file *file,
608 int enable, int soft_disable)
609{
610 struct trace_event_call *call = file->event_call;
611 struct trace_array *tr = file->tr;
612 unsigned long file_flags = file->flags;
613 int ret = 0;
614 int disable;
615
616 switch (enable) {
617 case 0:
618 /*
619 * When soft_disable is set and enable is cleared, the sm_ref
620 * reference counter is decremented. If it reaches 0, we want
621 * to clear the SOFT_DISABLED flag but leave the event in the
622 * state that it was. That is, if the event was enabled and
623 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
624 * is set we do not want the event to be enabled before we
625 * clear the bit.
626 *
627 * When soft_disable is not set but the SOFT_MODE flag is,
628 * we do nothing. Do not disable the tracepoint, otherwise
629 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
630 */
631 if (soft_disable) {
632 if (atomic_dec_return(&file->sm_ref) > 0)
633 break;
634 disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
635 clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
636 } else
637 disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
638
639 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
640 clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
641 if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
642 tracing_stop_cmdline_record();
643 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
644 }
645
646 if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
647 tracing_stop_tgid_record();
648 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
649 }
650
651 call->class->reg(call, TRACE_REG_UNREGISTER, file);
652 }
653 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
654 if (file->flags & EVENT_FILE_FL_SOFT_MODE)
655 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
656 else
657 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
658 break;
659 case 1:
660 /*
661 * When soft_disable is set and enable is set, we want to
662 * register the tracepoint for the event, but leave the event
663 * as is. That means, if the event was already enabled, we do
664 * nothing (but set SOFT_MODE). If the event is disabled, we
665 * set SOFT_DISABLED before enabling the event tracepoint, so
666 * it still seems to be disabled.
667 */
668 if (!soft_disable)
669 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
670 else {
671 if (atomic_inc_return(&file->sm_ref) > 1)
672 break;
673 set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
674 }
675
676 if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
677 bool cmd = false, tgid = false;
678
679 /* Keep the event disabled, when going to SOFT_MODE. */
680 if (soft_disable)
681 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
682
683 if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
684 cmd = true;
685 tracing_start_cmdline_record();
686 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
687 }
688
689 if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
690 tgid = true;
691 tracing_start_tgid_record();
692 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
693 }
694
695 ret = call->class->reg(call, TRACE_REG_REGISTER, file);
696 if (ret) {
697 if (cmd)
698 tracing_stop_cmdline_record();
699 if (tgid)
700 tracing_stop_tgid_record();
701 pr_info("event trace: Could not enable event "
702 "%s\n", trace_event_name(call));
703 break;
704 }
705 set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
706
707 /* WAS_ENABLED gets set but never cleared. */
708 set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
709 }
710 break;
711 }
712
713 /* Enable or disable use of trace_buffered_event */
714 if ((file_flags & EVENT_FILE_FL_SOFT_DISABLED) !=
715 (file->flags & EVENT_FILE_FL_SOFT_DISABLED)) {
716 if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
717 trace_buffered_event_enable();
718 else
719 trace_buffered_event_disable();
720 }
721
722 return ret;
723}
724
725int trace_event_enable_disable(struct trace_event_file *file,
726 int enable, int soft_disable)
727{
728 return __ftrace_event_enable_disable(file, enable, soft_disable);
729}
730
731static int ftrace_event_enable_disable(struct trace_event_file *file,
732 int enable)
733{
734 return __ftrace_event_enable_disable(file, enable, 0);
735}
736
737static void ftrace_clear_events(struct trace_array *tr)
738{
739 struct trace_event_file *file;
740
741 mutex_lock(&event_mutex);
742 list_for_each_entry(file, &tr->events, list) {
743 ftrace_event_enable_disable(file, 0);
744 }
745 mutex_unlock(&event_mutex);
746}
747
748static void
749event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
750{
751 struct trace_pid_list *pid_list;
752 struct trace_array *tr = data;
753
754 pid_list = rcu_dereference_raw(tr->filtered_pids);
755 trace_filter_add_remove_task(pid_list, NULL, task);
756
757 pid_list = rcu_dereference_raw(tr->filtered_no_pids);
758 trace_filter_add_remove_task(pid_list, NULL, task);
759}
760
761static void
762event_filter_pid_sched_process_fork(void *data,
763 struct task_struct *self,
764 struct task_struct *task)
765{
766 struct trace_pid_list *pid_list;
767 struct trace_array *tr = data;
768
769 pid_list = rcu_dereference_sched(tr->filtered_pids);
770 trace_filter_add_remove_task(pid_list, self, task);
771
772 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
773 trace_filter_add_remove_task(pid_list, self, task);
774}
775
776void trace_event_follow_fork(struct trace_array *tr, bool enable)
777{
778 if (enable) {
779 register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
780 tr, INT_MIN);
781 register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
782 tr, INT_MAX);
783 } else {
784 unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
785 tr);
786 unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
787 tr);
788 }
789}
790
791static void
792event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
793 struct task_struct *prev,
794 struct task_struct *next,
795 unsigned int prev_state)
796{
797 struct trace_array *tr = data;
798 struct trace_pid_list *no_pid_list;
799 struct trace_pid_list *pid_list;
800 bool ret;
801
802 pid_list = rcu_dereference_sched(tr->filtered_pids);
803 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
804
805 /*
806 * Sched switch is funny, as we only want to ignore it
807 * in the notrace case if both prev and next should be ignored.
808 */
809 ret = trace_ignore_this_task(NULL, no_pid_list, prev) &&
810 trace_ignore_this_task(NULL, no_pid_list, next);
811
812 this_cpu_write(tr->array_buffer.data->ignore_pid, ret ||
813 (trace_ignore_this_task(pid_list, NULL, prev) &&
814 trace_ignore_this_task(pid_list, NULL, next)));
815}
816
817static void
818event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
819 struct task_struct *prev,
820 struct task_struct *next,
821 unsigned int prev_state)
822{
823 struct trace_array *tr = data;
824 struct trace_pid_list *no_pid_list;
825 struct trace_pid_list *pid_list;
826
827 pid_list = rcu_dereference_sched(tr->filtered_pids);
828 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
829
830 this_cpu_write(tr->array_buffer.data->ignore_pid,
831 trace_ignore_this_task(pid_list, no_pid_list, next));
832}
833
834static void
835event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
836{
837 struct trace_array *tr = data;
838 struct trace_pid_list *no_pid_list;
839 struct trace_pid_list *pid_list;
840
841 /* Nothing to do if we are already tracing */
842 if (!this_cpu_read(tr->array_buffer.data->ignore_pid))
843 return;
844
845 pid_list = rcu_dereference_sched(tr->filtered_pids);
846 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
847
848 this_cpu_write(tr->array_buffer.data->ignore_pid,
849 trace_ignore_this_task(pid_list, no_pid_list, task));
850}
851
852static void
853event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
854{
855 struct trace_array *tr = data;
856 struct trace_pid_list *no_pid_list;
857 struct trace_pid_list *pid_list;
858
859 /* Nothing to do if we are not tracing */
860 if (this_cpu_read(tr->array_buffer.data->ignore_pid))
861 return;
862
863 pid_list = rcu_dereference_sched(tr->filtered_pids);
864 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
865
866 /* Set tracing if current is enabled */
867 this_cpu_write(tr->array_buffer.data->ignore_pid,
868 trace_ignore_this_task(pid_list, no_pid_list, current));
869}
870
871static void unregister_pid_events(struct trace_array *tr)
872{
873 unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
874 unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
875
876 unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
877 unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
878
879 unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
880 unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
881
882 unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
883 unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
884}
885
886static void __ftrace_clear_event_pids(struct trace_array *tr, int type)
887{
888 struct trace_pid_list *pid_list;
889 struct trace_pid_list *no_pid_list;
890 struct trace_event_file *file;
891 int cpu;
892
893 pid_list = rcu_dereference_protected(tr->filtered_pids,
894 lockdep_is_held(&event_mutex));
895 no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
896 lockdep_is_held(&event_mutex));
897
898 /* Make sure there's something to do */
899 if (!pid_type_enabled(type, pid_list, no_pid_list))
900 return;
901
902 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
903 unregister_pid_events(tr);
904
905 list_for_each_entry(file, &tr->events, list) {
906 clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
907 }
908
909 for_each_possible_cpu(cpu)
910 per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
911 }
912
913 if (type & TRACE_PIDS)
914 rcu_assign_pointer(tr->filtered_pids, NULL);
915
916 if (type & TRACE_NO_PIDS)
917 rcu_assign_pointer(tr->filtered_no_pids, NULL);
918
919 /* Wait till all users are no longer using pid filtering */
920 tracepoint_synchronize_unregister();
921
922 if ((type & TRACE_PIDS) && pid_list)
923 trace_pid_list_free(pid_list);
924
925 if ((type & TRACE_NO_PIDS) && no_pid_list)
926 trace_pid_list_free(no_pid_list);
927}
928
929static void ftrace_clear_event_pids(struct trace_array *tr, int type)
930{
931 mutex_lock(&event_mutex);
932 __ftrace_clear_event_pids(tr, type);
933 mutex_unlock(&event_mutex);
934}
935
936static void __put_system(struct event_subsystem *system)
937{
938 struct event_filter *filter = system->filter;
939
940 WARN_ON_ONCE(system_refcount(system) == 0);
941 if (system_refcount_dec(system))
942 return;
943
944 list_del(&system->list);
945
946 if (filter) {
947 kfree(filter->filter_string);
948 kfree(filter);
949 }
950 kfree_const(system->name);
951 kfree(system);
952}
953
954static void __get_system(struct event_subsystem *system)
955{
956 WARN_ON_ONCE(system_refcount(system) == 0);
957 system_refcount_inc(system);
958}
959
960static void __get_system_dir(struct trace_subsystem_dir *dir)
961{
962 WARN_ON_ONCE(dir->ref_count == 0);
963 dir->ref_count++;
964 __get_system(dir->subsystem);
965}
966
967static void __put_system_dir(struct trace_subsystem_dir *dir)
968{
969 WARN_ON_ONCE(dir->ref_count == 0);
970 /* If the subsystem is about to be freed, the dir must be too */
971 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
972
973 __put_system(dir->subsystem);
974 if (!--dir->ref_count)
975 kfree(dir);
976}
977
978static void put_system(struct trace_subsystem_dir *dir)
979{
980 mutex_lock(&event_mutex);
981 __put_system_dir(dir);
982 mutex_unlock(&event_mutex);
983}
984
985static void remove_subsystem(struct trace_subsystem_dir *dir)
986{
987 if (!dir)
988 return;
989
990 if (!--dir->nr_events) {
991 tracefs_remove(dir->entry);
992 list_del(&dir->list);
993 __put_system_dir(dir);
994 }
995}
996
997static void remove_event_file_dir(struct trace_event_file *file)
998{
999 struct dentry *dir = file->dir;
1000 struct dentry *child;
1001
1002 if (dir) {
1003 spin_lock(&dir->d_lock); /* probably unneeded */
1004 list_for_each_entry(child, &dir->d_subdirs, d_child) {
1005 if (d_really_is_positive(child)) /* probably unneeded */
1006 d_inode(child)->i_private = NULL;
1007 }
1008 spin_unlock(&dir->d_lock);
1009
1010 tracefs_remove(dir);
1011 }
1012
1013 list_del(&file->list);
1014 remove_subsystem(file->system);
1015 free_event_filter(file->filter);
1016 kmem_cache_free(file_cachep, file);
1017}
1018
1019/*
1020 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
1021 */
1022static int
1023__ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
1024 const char *sub, const char *event, int set)
1025{
1026 struct trace_event_file *file;
1027 struct trace_event_call *call;
1028 const char *name;
1029 int ret = -EINVAL;
1030 int eret = 0;
1031
1032 list_for_each_entry(file, &tr->events, list) {
1033
1034 call = file->event_call;
1035 name = trace_event_name(call);
1036
1037 if (!name || !call->class || !call->class->reg)
1038 continue;
1039
1040 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1041 continue;
1042
1043 if (match &&
1044 strcmp(match, name) != 0 &&
1045 strcmp(match, call->class->system) != 0)
1046 continue;
1047
1048 if (sub && strcmp(sub, call->class->system) != 0)
1049 continue;
1050
1051 if (event && strcmp(event, name) != 0)
1052 continue;
1053
1054 ret = ftrace_event_enable_disable(file, set);
1055
1056 /*
1057 * Save the first error and return that. Some events
1058 * may still have been enabled, but let the user
1059 * know that something went wrong.
1060 */
1061 if (ret && !eret)
1062 eret = ret;
1063
1064 ret = eret;
1065 }
1066
1067 return ret;
1068}
1069
1070static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
1071 const char *sub, const char *event, int set)
1072{
1073 int ret;
1074
1075 mutex_lock(&event_mutex);
1076 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
1077 mutex_unlock(&event_mutex);
1078
1079 return ret;
1080}
1081
1082int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
1083{
1084 char *event = NULL, *sub = NULL, *match;
1085 int ret;
1086
1087 if (!tr)
1088 return -ENOENT;
1089 /*
1090 * The buf format can be <subsystem>:<event-name>
1091 * *:<event-name> means any event by that name.
1092 * :<event-name> is the same.
1093 *
1094 * <subsystem>:* means all events in that subsystem
1095 * <subsystem>: means the same.
1096 *
1097 * <name> (no ':') means all events in a subsystem with
1098 * the name <name> or any event that matches <name>
1099 */
1100
1101 match = strsep(&buf, ":");
1102 if (buf) {
1103 sub = match;
1104 event = buf;
1105 match = NULL;
1106
1107 if (!strlen(sub) || strcmp(sub, "*") == 0)
1108 sub = NULL;
1109 if (!strlen(event) || strcmp(event, "*") == 0)
1110 event = NULL;
1111 }
1112
1113 ret = __ftrace_set_clr_event(tr, match, sub, event, set);
1114
1115 /* Put back the colon to allow this to be called again */
1116 if (buf)
1117 *(buf - 1) = ':';
1118
1119 return ret;
1120}
1121
1122/**
1123 * trace_set_clr_event - enable or disable an event
1124 * @system: system name to match (NULL for any system)
1125 * @event: event name to match (NULL for all events, within system)
1126 * @set: 1 to enable, 0 to disable
1127 *
1128 * This is a way for other parts of the kernel to enable or disable
1129 * event recording.
1130 *
1131 * Returns 0 on success, -EINVAL if the parameters do not match any
1132 * registered events.
1133 */
1134int trace_set_clr_event(const char *system, const char *event, int set)
1135{
1136 struct trace_array *tr = top_trace_array();
1137
1138 if (!tr)
1139 return -ENODEV;
1140
1141 return __ftrace_set_clr_event(tr, NULL, system, event, set);
1142}
1143EXPORT_SYMBOL_GPL(trace_set_clr_event);
1144
1145/**
1146 * trace_array_set_clr_event - enable or disable an event for a trace array.
1147 * @tr: concerned trace array.
1148 * @system: system name to match (NULL for any system)
1149 * @event: event name to match (NULL for all events, within system)
1150 * @enable: true to enable, false to disable
1151 *
1152 * This is a way for other parts of the kernel to enable or disable
1153 * event recording.
1154 *
1155 * Returns 0 on success, -EINVAL if the parameters do not match any
1156 * registered events.
1157 */
1158int trace_array_set_clr_event(struct trace_array *tr, const char *system,
1159 const char *event, bool enable)
1160{
1161 int set;
1162
1163 if (!tr)
1164 return -ENOENT;
1165
1166 set = (enable == true) ? 1 : 0;
1167 return __ftrace_set_clr_event(tr, NULL, system, event, set);
1168}
1169EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
1170
1171/* 128 should be much more than enough */
1172#define EVENT_BUF_SIZE 127
1173
1174static ssize_t
1175ftrace_event_write(struct file *file, const char __user *ubuf,
1176 size_t cnt, loff_t *ppos)
1177{
1178 struct trace_parser parser;
1179 struct seq_file *m = file->private_data;
1180 struct trace_array *tr = m->private;
1181 ssize_t read, ret;
1182
1183 if (!cnt)
1184 return 0;
1185
1186 ret = tracing_update_buffers();
1187 if (ret < 0)
1188 return ret;
1189
1190 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
1191 return -ENOMEM;
1192
1193 read = trace_get_user(&parser, ubuf, cnt, ppos);
1194
1195 if (read >= 0 && trace_parser_loaded((&parser))) {
1196 int set = 1;
1197
1198 if (*parser.buffer == '!')
1199 set = 0;
1200
1201 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
1202 if (ret)
1203 goto out_put;
1204 }
1205
1206 ret = read;
1207
1208 out_put:
1209 trace_parser_put(&parser);
1210
1211 return ret;
1212}
1213
1214static void *
1215t_next(struct seq_file *m, void *v, loff_t *pos)
1216{
1217 struct trace_event_file *file = v;
1218 struct trace_event_call *call;
1219 struct trace_array *tr = m->private;
1220
1221 (*pos)++;
1222
1223 list_for_each_entry_continue(file, &tr->events, list) {
1224 call = file->event_call;
1225 /*
1226 * The ftrace subsystem is for showing formats only.
1227 * They can not be enabled or disabled via the event files.
1228 */
1229 if (call->class && call->class->reg &&
1230 !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1231 return file;
1232 }
1233
1234 return NULL;
1235}
1236
1237static void *t_start(struct seq_file *m, loff_t *pos)
1238{
1239 struct trace_event_file *file;
1240 struct trace_array *tr = m->private;
1241 loff_t l;
1242
1243 mutex_lock(&event_mutex);
1244
1245 file = list_entry(&tr->events, struct trace_event_file, list);
1246 for (l = 0; l <= *pos; ) {
1247 file = t_next(m, file, &l);
1248 if (!file)
1249 break;
1250 }
1251 return file;
1252}
1253
1254static void *
1255s_next(struct seq_file *m, void *v, loff_t *pos)
1256{
1257 struct trace_event_file *file = v;
1258 struct trace_array *tr = m->private;
1259
1260 (*pos)++;
1261
1262 list_for_each_entry_continue(file, &tr->events, list) {
1263 if (file->flags & EVENT_FILE_FL_ENABLED)
1264 return file;
1265 }
1266
1267 return NULL;
1268}
1269
1270static void *s_start(struct seq_file *m, loff_t *pos)
1271{
1272 struct trace_event_file *file;
1273 struct trace_array *tr = m->private;
1274 loff_t l;
1275
1276 mutex_lock(&event_mutex);
1277
1278 file = list_entry(&tr->events, struct trace_event_file, list);
1279 for (l = 0; l <= *pos; ) {
1280 file = s_next(m, file, &l);
1281 if (!file)
1282 break;
1283 }
1284 return file;
1285}
1286
1287static int t_show(struct seq_file *m, void *v)
1288{
1289 struct trace_event_file *file = v;
1290 struct trace_event_call *call = file->event_call;
1291
1292 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1293 seq_printf(m, "%s:", call->class->system);
1294 seq_printf(m, "%s\n", trace_event_name(call));
1295
1296 return 0;
1297}
1298
1299static void t_stop(struct seq_file *m, void *p)
1300{
1301 mutex_unlock(&event_mutex);
1302}
1303
1304static void *
1305__next(struct seq_file *m, void *v, loff_t *pos, int type)
1306{
1307 struct trace_array *tr = m->private;
1308 struct trace_pid_list *pid_list;
1309
1310 if (type == TRACE_PIDS)
1311 pid_list = rcu_dereference_sched(tr->filtered_pids);
1312 else
1313 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1314
1315 return trace_pid_next(pid_list, v, pos);
1316}
1317
1318static void *
1319p_next(struct seq_file *m, void *v, loff_t *pos)
1320{
1321 return __next(m, v, pos, TRACE_PIDS);
1322}
1323
1324static void *
1325np_next(struct seq_file *m, void *v, loff_t *pos)
1326{
1327 return __next(m, v, pos, TRACE_NO_PIDS);
1328}
1329
1330static void *__start(struct seq_file *m, loff_t *pos, int type)
1331 __acquires(RCU)
1332{
1333 struct trace_pid_list *pid_list;
1334 struct trace_array *tr = m->private;
1335
1336 /*
1337 * Grab the mutex, to keep calls to p_next() having the same
1338 * tr->filtered_pids as p_start() has.
1339 * If we just passed the tr->filtered_pids around, then RCU would
1340 * have been enough, but doing that makes things more complex.
1341 */
1342 mutex_lock(&event_mutex);
1343 rcu_read_lock_sched();
1344
1345 if (type == TRACE_PIDS)
1346 pid_list = rcu_dereference_sched(tr->filtered_pids);
1347 else
1348 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1349
1350 if (!pid_list)
1351 return NULL;
1352
1353 return trace_pid_start(pid_list, pos);
1354}
1355
1356static void *p_start(struct seq_file *m, loff_t *pos)
1357 __acquires(RCU)
1358{
1359 return __start(m, pos, TRACE_PIDS);
1360}
1361
1362static void *np_start(struct seq_file *m, loff_t *pos)
1363 __acquires(RCU)
1364{
1365 return __start(m, pos, TRACE_NO_PIDS);
1366}
1367
1368static void p_stop(struct seq_file *m, void *p)
1369 __releases(RCU)
1370{
1371 rcu_read_unlock_sched();
1372 mutex_unlock(&event_mutex);
1373}
1374
1375static ssize_t
1376event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1377 loff_t *ppos)
1378{
1379 struct trace_event_file *file;
1380 unsigned long flags;
1381 char buf[4] = "0";
1382
1383 mutex_lock(&event_mutex);
1384 file = event_file_data(filp);
1385 if (likely(file))
1386 flags = file->flags;
1387 mutex_unlock(&event_mutex);
1388
1389 if (!file)
1390 return -ENODEV;
1391
1392 if (flags & EVENT_FILE_FL_ENABLED &&
1393 !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1394 strcpy(buf, "1");
1395
1396 if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1397 flags & EVENT_FILE_FL_SOFT_MODE)
1398 strcat(buf, "*");
1399
1400 strcat(buf, "\n");
1401
1402 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1403}
1404
1405static ssize_t
1406event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1407 loff_t *ppos)
1408{
1409 struct trace_event_file *file;
1410 unsigned long val;
1411 int ret;
1412
1413 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1414 if (ret)
1415 return ret;
1416
1417 ret = tracing_update_buffers();
1418 if (ret < 0)
1419 return ret;
1420
1421 switch (val) {
1422 case 0:
1423 case 1:
1424 ret = -ENODEV;
1425 mutex_lock(&event_mutex);
1426 file = event_file_data(filp);
1427 if (likely(file))
1428 ret = ftrace_event_enable_disable(file, val);
1429 mutex_unlock(&event_mutex);
1430 break;
1431
1432 default:
1433 return -EINVAL;
1434 }
1435
1436 *ppos += cnt;
1437
1438 return ret ? ret : cnt;
1439}
1440
1441static ssize_t
1442system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1443 loff_t *ppos)
1444{
1445 const char set_to_char[4] = { '?', '0', '1', 'X' };
1446 struct trace_subsystem_dir *dir = filp->private_data;
1447 struct event_subsystem *system = dir->subsystem;
1448 struct trace_event_call *call;
1449 struct trace_event_file *file;
1450 struct trace_array *tr = dir->tr;
1451 char buf[2];
1452 int set = 0;
1453 int ret;
1454
1455 mutex_lock(&event_mutex);
1456 list_for_each_entry(file, &tr->events, list) {
1457 call = file->event_call;
1458 if ((call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
1459 !trace_event_name(call) || !call->class || !call->class->reg)
1460 continue;
1461
1462 if (system && strcmp(call->class->system, system->name) != 0)
1463 continue;
1464
1465 /*
1466 * We need to find out if all the events are set
1467 * or if all events or cleared, or if we have
1468 * a mixture.
1469 */
1470 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1471
1472 /*
1473 * If we have a mixture, no need to look further.
1474 */
1475 if (set == 3)
1476 break;
1477 }
1478 mutex_unlock(&event_mutex);
1479
1480 buf[0] = set_to_char[set];
1481 buf[1] = '\n';
1482
1483 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1484
1485 return ret;
1486}
1487
1488static ssize_t
1489system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1490 loff_t *ppos)
1491{
1492 struct trace_subsystem_dir *dir = filp->private_data;
1493 struct event_subsystem *system = dir->subsystem;
1494 const char *name = NULL;
1495 unsigned long val;
1496 ssize_t ret;
1497
1498 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1499 if (ret)
1500 return ret;
1501
1502 ret = tracing_update_buffers();
1503 if (ret < 0)
1504 return ret;
1505
1506 if (val != 0 && val != 1)
1507 return -EINVAL;
1508
1509 /*
1510 * Opening of "enable" adds a ref count to system,
1511 * so the name is safe to use.
1512 */
1513 if (system)
1514 name = system->name;
1515
1516 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1517 if (ret)
1518 goto out;
1519
1520 ret = cnt;
1521
1522out:
1523 *ppos += cnt;
1524
1525 return ret;
1526}
1527
1528enum {
1529 FORMAT_HEADER = 1,
1530 FORMAT_FIELD_SEPERATOR = 2,
1531 FORMAT_PRINTFMT = 3,
1532};
1533
1534static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1535{
1536 struct trace_event_call *call = event_file_data(m->private);
1537 struct list_head *common_head = &ftrace_common_fields;
1538 struct list_head *head = trace_get_fields(call);
1539 struct list_head *node = v;
1540
1541 (*pos)++;
1542
1543 switch ((unsigned long)v) {
1544 case FORMAT_HEADER:
1545 node = common_head;
1546 break;
1547
1548 case FORMAT_FIELD_SEPERATOR:
1549 node = head;
1550 break;
1551
1552 case FORMAT_PRINTFMT:
1553 /* all done */
1554 return NULL;
1555 }
1556
1557 node = node->prev;
1558 if (node == common_head)
1559 return (void *)FORMAT_FIELD_SEPERATOR;
1560 else if (node == head)
1561 return (void *)FORMAT_PRINTFMT;
1562 else
1563 return node;
1564}
1565
1566static int f_show(struct seq_file *m, void *v)
1567{
1568 struct trace_event_call *call = event_file_data(m->private);
1569 struct ftrace_event_field *field;
1570 const char *array_descriptor;
1571
1572 switch ((unsigned long)v) {
1573 case FORMAT_HEADER:
1574 seq_printf(m, "name: %s\n", trace_event_name(call));
1575 seq_printf(m, "ID: %d\n", call->event.type);
1576 seq_puts(m, "format:\n");
1577 return 0;
1578
1579 case FORMAT_FIELD_SEPERATOR:
1580 seq_putc(m, '\n');
1581 return 0;
1582
1583 case FORMAT_PRINTFMT:
1584 seq_printf(m, "\nprint fmt: %s\n",
1585 call->print_fmt);
1586 return 0;
1587 }
1588
1589 field = list_entry(v, struct ftrace_event_field, link);
1590 /*
1591 * Smartly shows the array type(except dynamic array).
1592 * Normal:
1593 * field:TYPE VAR
1594 * If TYPE := TYPE[LEN], it is shown:
1595 * field:TYPE VAR[LEN]
1596 */
1597 array_descriptor = strchr(field->type, '[');
1598
1599 if (str_has_prefix(field->type, "__data_loc"))
1600 array_descriptor = NULL;
1601
1602 if (!array_descriptor)
1603 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1604 field->type, field->name, field->offset,
1605 field->size, !!field->is_signed);
1606 else if (field->len)
1607 seq_printf(m, "\tfield:%.*s %s[%d];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1608 (int)(array_descriptor - field->type),
1609 field->type, field->name,
1610 field->len, field->offset,
1611 field->size, !!field->is_signed);
1612 else
1613 seq_printf(m, "\tfield:%.*s %s[];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1614 (int)(array_descriptor - field->type),
1615 field->type, field->name,
1616 field->offset, field->size, !!field->is_signed);
1617
1618 return 0;
1619}
1620
1621static void *f_start(struct seq_file *m, loff_t *pos)
1622{
1623 void *p = (void *)FORMAT_HEADER;
1624 loff_t l = 0;
1625
1626 /* ->stop() is called even if ->start() fails */
1627 mutex_lock(&event_mutex);
1628 if (!event_file_data(m->private))
1629 return ERR_PTR(-ENODEV);
1630
1631 while (l < *pos && p)
1632 p = f_next(m, p, &l);
1633
1634 return p;
1635}
1636
1637static void f_stop(struct seq_file *m, void *p)
1638{
1639 mutex_unlock(&event_mutex);
1640}
1641
1642static const struct seq_operations trace_format_seq_ops = {
1643 .start = f_start,
1644 .next = f_next,
1645 .stop = f_stop,
1646 .show = f_show,
1647};
1648
1649static int trace_format_open(struct inode *inode, struct file *file)
1650{
1651 struct seq_file *m;
1652 int ret;
1653
1654 /* Do we want to hide event format files on tracefs lockdown? */
1655
1656 ret = seq_open(file, &trace_format_seq_ops);
1657 if (ret < 0)
1658 return ret;
1659
1660 m = file->private_data;
1661 m->private = file;
1662
1663 return 0;
1664}
1665
1666static ssize_t
1667event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1668{
1669 int id = (long)event_file_data(filp);
1670 char buf[32];
1671 int len;
1672
1673 if (unlikely(!id))
1674 return -ENODEV;
1675
1676 len = sprintf(buf, "%d\n", id);
1677
1678 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1679}
1680
1681static ssize_t
1682event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1683 loff_t *ppos)
1684{
1685 struct trace_event_file *file;
1686 struct trace_seq *s;
1687 int r = -ENODEV;
1688
1689 if (*ppos)
1690 return 0;
1691
1692 s = kmalloc(sizeof(*s), GFP_KERNEL);
1693
1694 if (!s)
1695 return -ENOMEM;
1696
1697 trace_seq_init(s);
1698
1699 mutex_lock(&event_mutex);
1700 file = event_file_data(filp);
1701 if (file)
1702 print_event_filter(file, s);
1703 mutex_unlock(&event_mutex);
1704
1705 if (file)
1706 r = simple_read_from_buffer(ubuf, cnt, ppos,
1707 s->buffer, trace_seq_used(s));
1708
1709 kfree(s);
1710
1711 return r;
1712}
1713
1714static ssize_t
1715event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1716 loff_t *ppos)
1717{
1718 struct trace_event_file *file;
1719 char *buf;
1720 int err = -ENODEV;
1721
1722 if (cnt >= PAGE_SIZE)
1723 return -EINVAL;
1724
1725 buf = memdup_user_nul(ubuf, cnt);
1726 if (IS_ERR(buf))
1727 return PTR_ERR(buf);
1728
1729 mutex_lock(&event_mutex);
1730 file = event_file_data(filp);
1731 if (file)
1732 err = apply_event_filter(file, buf);
1733 mutex_unlock(&event_mutex);
1734
1735 kfree(buf);
1736 if (err < 0)
1737 return err;
1738
1739 *ppos += cnt;
1740
1741 return cnt;
1742}
1743
1744static LIST_HEAD(event_subsystems);
1745
1746static int subsystem_open(struct inode *inode, struct file *filp)
1747{
1748 struct trace_subsystem_dir *dir = NULL, *iter_dir;
1749 struct trace_array *tr = NULL, *iter_tr;
1750 struct event_subsystem *system = NULL;
1751 int ret;
1752
1753 if (tracing_is_disabled())
1754 return -ENODEV;
1755
1756 /* Make sure the system still exists */
1757 mutex_lock(&event_mutex);
1758 mutex_lock(&trace_types_lock);
1759 list_for_each_entry(iter_tr, &ftrace_trace_arrays, list) {
1760 list_for_each_entry(iter_dir, &iter_tr->systems, list) {
1761 if (iter_dir == inode->i_private) {
1762 /* Don't open systems with no events */
1763 tr = iter_tr;
1764 dir = iter_dir;
1765 if (dir->nr_events) {
1766 __get_system_dir(dir);
1767 system = dir->subsystem;
1768 }
1769 goto exit_loop;
1770 }
1771 }
1772 }
1773 exit_loop:
1774 mutex_unlock(&trace_types_lock);
1775 mutex_unlock(&event_mutex);
1776
1777 if (!system)
1778 return -ENODEV;
1779
1780 /* Still need to increment the ref count of the system */
1781 if (trace_array_get(tr) < 0) {
1782 put_system(dir);
1783 return -ENODEV;
1784 }
1785
1786 ret = tracing_open_generic(inode, filp);
1787 if (ret < 0) {
1788 trace_array_put(tr);
1789 put_system(dir);
1790 }
1791
1792 return ret;
1793}
1794
1795static int system_tr_open(struct inode *inode, struct file *filp)
1796{
1797 struct trace_subsystem_dir *dir;
1798 struct trace_array *tr = inode->i_private;
1799 int ret;
1800
1801 /* Make a temporary dir that has no system but points to tr */
1802 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1803 if (!dir)
1804 return -ENOMEM;
1805
1806 ret = tracing_open_generic_tr(inode, filp);
1807 if (ret < 0) {
1808 kfree(dir);
1809 return ret;
1810 }
1811 dir->tr = tr;
1812 filp->private_data = dir;
1813
1814 return 0;
1815}
1816
1817static int subsystem_release(struct inode *inode, struct file *file)
1818{
1819 struct trace_subsystem_dir *dir = file->private_data;
1820
1821 trace_array_put(dir->tr);
1822
1823 /*
1824 * If dir->subsystem is NULL, then this is a temporary
1825 * descriptor that was made for a trace_array to enable
1826 * all subsystems.
1827 */
1828 if (dir->subsystem)
1829 put_system(dir);
1830 else
1831 kfree(dir);
1832
1833 return 0;
1834}
1835
1836static ssize_t
1837subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1838 loff_t *ppos)
1839{
1840 struct trace_subsystem_dir *dir = filp->private_data;
1841 struct event_subsystem *system = dir->subsystem;
1842 struct trace_seq *s;
1843 int r;
1844
1845 if (*ppos)
1846 return 0;
1847
1848 s = kmalloc(sizeof(*s), GFP_KERNEL);
1849 if (!s)
1850 return -ENOMEM;
1851
1852 trace_seq_init(s);
1853
1854 print_subsystem_event_filter(system, s);
1855 r = simple_read_from_buffer(ubuf, cnt, ppos,
1856 s->buffer, trace_seq_used(s));
1857
1858 kfree(s);
1859
1860 return r;
1861}
1862
1863static ssize_t
1864subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1865 loff_t *ppos)
1866{
1867 struct trace_subsystem_dir *dir = filp->private_data;
1868 char *buf;
1869 int err;
1870
1871 if (cnt >= PAGE_SIZE)
1872 return -EINVAL;
1873
1874 buf = memdup_user_nul(ubuf, cnt);
1875 if (IS_ERR(buf))
1876 return PTR_ERR(buf);
1877
1878 err = apply_subsystem_event_filter(dir, buf);
1879 kfree(buf);
1880 if (err < 0)
1881 return err;
1882
1883 *ppos += cnt;
1884
1885 return cnt;
1886}
1887
1888static ssize_t
1889show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1890{
1891 int (*func)(struct trace_seq *s) = filp->private_data;
1892 struct trace_seq *s;
1893 int r;
1894
1895 if (*ppos)
1896 return 0;
1897
1898 s = kmalloc(sizeof(*s), GFP_KERNEL);
1899 if (!s)
1900 return -ENOMEM;
1901
1902 trace_seq_init(s);
1903
1904 func(s);
1905 r = simple_read_from_buffer(ubuf, cnt, ppos,
1906 s->buffer, trace_seq_used(s));
1907
1908 kfree(s);
1909
1910 return r;
1911}
1912
1913static void ignore_task_cpu(void *data)
1914{
1915 struct trace_array *tr = data;
1916 struct trace_pid_list *pid_list;
1917 struct trace_pid_list *no_pid_list;
1918
1919 /*
1920 * This function is called by on_each_cpu() while the
1921 * event_mutex is held.
1922 */
1923 pid_list = rcu_dereference_protected(tr->filtered_pids,
1924 mutex_is_locked(&event_mutex));
1925 no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
1926 mutex_is_locked(&event_mutex));
1927
1928 this_cpu_write(tr->array_buffer.data->ignore_pid,
1929 trace_ignore_this_task(pid_list, no_pid_list, current));
1930}
1931
1932static void register_pid_events(struct trace_array *tr)
1933{
1934 /*
1935 * Register a probe that is called before all other probes
1936 * to set ignore_pid if next or prev do not match.
1937 * Register a probe this is called after all other probes
1938 * to only keep ignore_pid set if next pid matches.
1939 */
1940 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1941 tr, INT_MAX);
1942 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1943 tr, 0);
1944
1945 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1946 tr, INT_MAX);
1947 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1948 tr, 0);
1949
1950 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1951 tr, INT_MAX);
1952 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1953 tr, 0);
1954
1955 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1956 tr, INT_MAX);
1957 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1958 tr, 0);
1959}
1960
1961static ssize_t
1962event_pid_write(struct file *filp, const char __user *ubuf,
1963 size_t cnt, loff_t *ppos, int type)
1964{
1965 struct seq_file *m = filp->private_data;
1966 struct trace_array *tr = m->private;
1967 struct trace_pid_list *filtered_pids = NULL;
1968 struct trace_pid_list *other_pids = NULL;
1969 struct trace_pid_list *pid_list;
1970 struct trace_event_file *file;
1971 ssize_t ret;
1972
1973 if (!cnt)
1974 return 0;
1975
1976 ret = tracing_update_buffers();
1977 if (ret < 0)
1978 return ret;
1979
1980 mutex_lock(&event_mutex);
1981
1982 if (type == TRACE_PIDS) {
1983 filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1984 lockdep_is_held(&event_mutex));
1985 other_pids = rcu_dereference_protected(tr->filtered_no_pids,
1986 lockdep_is_held(&event_mutex));
1987 } else {
1988 filtered_pids = rcu_dereference_protected(tr->filtered_no_pids,
1989 lockdep_is_held(&event_mutex));
1990 other_pids = rcu_dereference_protected(tr->filtered_pids,
1991 lockdep_is_held(&event_mutex));
1992 }
1993
1994 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
1995 if (ret < 0)
1996 goto out;
1997
1998 if (type == TRACE_PIDS)
1999 rcu_assign_pointer(tr->filtered_pids, pid_list);
2000 else
2001 rcu_assign_pointer(tr->filtered_no_pids, pid_list);
2002
2003 list_for_each_entry(file, &tr->events, list) {
2004 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
2005 }
2006
2007 if (filtered_pids) {
2008 tracepoint_synchronize_unregister();
2009 trace_pid_list_free(filtered_pids);
2010 } else if (pid_list && !other_pids) {
2011 register_pid_events(tr);
2012 }
2013
2014 /*
2015 * Ignoring of pids is done at task switch. But we have to
2016 * check for those tasks that are currently running.
2017 * Always do this in case a pid was appended or removed.
2018 */
2019 on_each_cpu(ignore_task_cpu, tr, 1);
2020
2021 out:
2022 mutex_unlock(&event_mutex);
2023
2024 if (ret > 0)
2025 *ppos += ret;
2026
2027 return ret;
2028}
2029
2030static ssize_t
2031ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
2032 size_t cnt, loff_t *ppos)
2033{
2034 return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
2035}
2036
2037static ssize_t
2038ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
2039 size_t cnt, loff_t *ppos)
2040{
2041 return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
2042}
2043
2044static int ftrace_event_avail_open(struct inode *inode, struct file *file);
2045static int ftrace_event_set_open(struct inode *inode, struct file *file);
2046static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
2047static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
2048static int ftrace_event_release(struct inode *inode, struct file *file);
2049
2050static const struct seq_operations show_event_seq_ops = {
2051 .start = t_start,
2052 .next = t_next,
2053 .show = t_show,
2054 .stop = t_stop,
2055};
2056
2057static const struct seq_operations show_set_event_seq_ops = {
2058 .start = s_start,
2059 .next = s_next,
2060 .show = t_show,
2061 .stop = t_stop,
2062};
2063
2064static const struct seq_operations show_set_pid_seq_ops = {
2065 .start = p_start,
2066 .next = p_next,
2067 .show = trace_pid_show,
2068 .stop = p_stop,
2069};
2070
2071static const struct seq_operations show_set_no_pid_seq_ops = {
2072 .start = np_start,
2073 .next = np_next,
2074 .show = trace_pid_show,
2075 .stop = p_stop,
2076};
2077
2078static const struct file_operations ftrace_avail_fops = {
2079 .open = ftrace_event_avail_open,
2080 .read = seq_read,
2081 .llseek = seq_lseek,
2082 .release = seq_release,
2083};
2084
2085static const struct file_operations ftrace_set_event_fops = {
2086 .open = ftrace_event_set_open,
2087 .read = seq_read,
2088 .write = ftrace_event_write,
2089 .llseek = seq_lseek,
2090 .release = ftrace_event_release,
2091};
2092
2093static const struct file_operations ftrace_set_event_pid_fops = {
2094 .open = ftrace_event_set_pid_open,
2095 .read = seq_read,
2096 .write = ftrace_event_pid_write,
2097 .llseek = seq_lseek,
2098 .release = ftrace_event_release,
2099};
2100
2101static const struct file_operations ftrace_set_event_notrace_pid_fops = {
2102 .open = ftrace_event_set_npid_open,
2103 .read = seq_read,
2104 .write = ftrace_event_npid_write,
2105 .llseek = seq_lseek,
2106 .release = ftrace_event_release,
2107};
2108
2109static const struct file_operations ftrace_enable_fops = {
2110 .open = tracing_open_generic,
2111 .read = event_enable_read,
2112 .write = event_enable_write,
2113 .llseek = default_llseek,
2114};
2115
2116static const struct file_operations ftrace_event_format_fops = {
2117 .open = trace_format_open,
2118 .read = seq_read,
2119 .llseek = seq_lseek,
2120 .release = seq_release,
2121};
2122
2123static const struct file_operations ftrace_event_id_fops = {
2124 .read = event_id_read,
2125 .llseek = default_llseek,
2126};
2127
2128static const struct file_operations ftrace_event_filter_fops = {
2129 .open = tracing_open_generic,
2130 .read = event_filter_read,
2131 .write = event_filter_write,
2132 .llseek = default_llseek,
2133};
2134
2135static const struct file_operations ftrace_subsystem_filter_fops = {
2136 .open = subsystem_open,
2137 .read = subsystem_filter_read,
2138 .write = subsystem_filter_write,
2139 .llseek = default_llseek,
2140 .release = subsystem_release,
2141};
2142
2143static const struct file_operations ftrace_system_enable_fops = {
2144 .open = subsystem_open,
2145 .read = system_enable_read,
2146 .write = system_enable_write,
2147 .llseek = default_llseek,
2148 .release = subsystem_release,
2149};
2150
2151static const struct file_operations ftrace_tr_enable_fops = {
2152 .open = system_tr_open,
2153 .read = system_enable_read,
2154 .write = system_enable_write,
2155 .llseek = default_llseek,
2156 .release = subsystem_release,
2157};
2158
2159static const struct file_operations ftrace_show_header_fops = {
2160 .open = tracing_open_generic,
2161 .read = show_header,
2162 .llseek = default_llseek,
2163};
2164
2165static int
2166ftrace_event_open(struct inode *inode, struct file *file,
2167 const struct seq_operations *seq_ops)
2168{
2169 struct seq_file *m;
2170 int ret;
2171
2172 ret = security_locked_down(LOCKDOWN_TRACEFS);
2173 if (ret)
2174 return ret;
2175
2176 ret = seq_open(file, seq_ops);
2177 if (ret < 0)
2178 return ret;
2179 m = file->private_data;
2180 /* copy tr over to seq ops */
2181 m->private = inode->i_private;
2182
2183 return ret;
2184}
2185
2186static int ftrace_event_release(struct inode *inode, struct file *file)
2187{
2188 struct trace_array *tr = inode->i_private;
2189
2190 trace_array_put(tr);
2191
2192 return seq_release(inode, file);
2193}
2194
2195static int
2196ftrace_event_avail_open(struct inode *inode, struct file *file)
2197{
2198 const struct seq_operations *seq_ops = &show_event_seq_ops;
2199
2200 /* Checks for tracefs lockdown */
2201 return ftrace_event_open(inode, file, seq_ops);
2202}
2203
2204static int
2205ftrace_event_set_open(struct inode *inode, struct file *file)
2206{
2207 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
2208 struct trace_array *tr = inode->i_private;
2209 int ret;
2210
2211 ret = tracing_check_open_get_tr(tr);
2212 if (ret)
2213 return ret;
2214
2215 if ((file->f_mode & FMODE_WRITE) &&
2216 (file->f_flags & O_TRUNC))
2217 ftrace_clear_events(tr);
2218
2219 ret = ftrace_event_open(inode, file, seq_ops);
2220 if (ret < 0)
2221 trace_array_put(tr);
2222 return ret;
2223}
2224
2225static int
2226ftrace_event_set_pid_open(struct inode *inode, struct file *file)
2227{
2228 const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
2229 struct trace_array *tr = inode->i_private;
2230 int ret;
2231
2232 ret = tracing_check_open_get_tr(tr);
2233 if (ret)
2234 return ret;
2235
2236 if ((file->f_mode & FMODE_WRITE) &&
2237 (file->f_flags & O_TRUNC))
2238 ftrace_clear_event_pids(tr, TRACE_PIDS);
2239
2240 ret = ftrace_event_open(inode, file, seq_ops);
2241 if (ret < 0)
2242 trace_array_put(tr);
2243 return ret;
2244}
2245
2246static int
2247ftrace_event_set_npid_open(struct inode *inode, struct file *file)
2248{
2249 const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops;
2250 struct trace_array *tr = inode->i_private;
2251 int ret;
2252
2253 ret = tracing_check_open_get_tr(tr);
2254 if (ret)
2255 return ret;
2256
2257 if ((file->f_mode & FMODE_WRITE) &&
2258 (file->f_flags & O_TRUNC))
2259 ftrace_clear_event_pids(tr, TRACE_NO_PIDS);
2260
2261 ret = ftrace_event_open(inode, file, seq_ops);
2262 if (ret < 0)
2263 trace_array_put(tr);
2264 return ret;
2265}
2266
2267static struct event_subsystem *
2268create_new_subsystem(const char *name)
2269{
2270 struct event_subsystem *system;
2271
2272 /* need to create new entry */
2273 system = kmalloc(sizeof(*system), GFP_KERNEL);
2274 if (!system)
2275 return NULL;
2276
2277 system->ref_count = 1;
2278
2279 /* Only allocate if dynamic (kprobes and modules) */
2280 system->name = kstrdup_const(name, GFP_KERNEL);
2281 if (!system->name)
2282 goto out_free;
2283
2284 system->filter = NULL;
2285
2286 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
2287 if (!system->filter)
2288 goto out_free;
2289
2290 list_add(&system->list, &event_subsystems);
2291
2292 return system;
2293
2294 out_free:
2295 kfree_const(system->name);
2296 kfree(system);
2297 return NULL;
2298}
2299
2300static struct dentry *
2301event_subsystem_dir(struct trace_array *tr, const char *name,
2302 struct trace_event_file *file, struct dentry *parent)
2303{
2304 struct event_subsystem *system, *iter;
2305 struct trace_subsystem_dir *dir;
2306 struct dentry *entry;
2307
2308 /* First see if we did not already create this dir */
2309 list_for_each_entry(dir, &tr->systems, list) {
2310 system = dir->subsystem;
2311 if (strcmp(system->name, name) == 0) {
2312 dir->nr_events++;
2313 file->system = dir;
2314 return dir->entry;
2315 }
2316 }
2317
2318 /* Now see if the system itself exists. */
2319 system = NULL;
2320 list_for_each_entry(iter, &event_subsystems, list) {
2321 if (strcmp(iter->name, name) == 0) {
2322 system = iter;
2323 break;
2324 }
2325 }
2326
2327 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
2328 if (!dir)
2329 goto out_fail;
2330
2331 if (!system) {
2332 system = create_new_subsystem(name);
2333 if (!system)
2334 goto out_free;
2335 } else
2336 __get_system(system);
2337
2338 dir->entry = tracefs_create_dir(name, parent);
2339 if (!dir->entry) {
2340 pr_warn("Failed to create system directory %s\n", name);
2341 __put_system(system);
2342 goto out_free;
2343 }
2344
2345 dir->tr = tr;
2346 dir->ref_count = 1;
2347 dir->nr_events = 1;
2348 dir->subsystem = system;
2349 file->system = dir;
2350
2351 /* the ftrace system is special, do not create enable or filter files */
2352 if (strcmp(name, "ftrace") != 0) {
2353
2354 entry = tracefs_create_file("filter", TRACE_MODE_WRITE,
2355 dir->entry, dir,
2356 &ftrace_subsystem_filter_fops);
2357 if (!entry) {
2358 kfree(system->filter);
2359 system->filter = NULL;
2360 pr_warn("Could not create tracefs '%s/filter' entry\n", name);
2361 }
2362
2363 trace_create_file("enable", TRACE_MODE_WRITE, dir->entry, dir,
2364 &ftrace_system_enable_fops);
2365 }
2366
2367 list_add(&dir->list, &tr->systems);
2368
2369 return dir->entry;
2370
2371 out_free:
2372 kfree(dir);
2373 out_fail:
2374 /* Only print this message if failed on memory allocation */
2375 if (!dir || !system)
2376 pr_warn("No memory to create event subsystem %s\n", name);
2377 return NULL;
2378}
2379
2380static int
2381event_define_fields(struct trace_event_call *call)
2382{
2383 struct list_head *head;
2384 int ret = 0;
2385
2386 /*
2387 * Other events may have the same class. Only update
2388 * the fields if they are not already defined.
2389 */
2390 head = trace_get_fields(call);
2391 if (list_empty(head)) {
2392 struct trace_event_fields *field = call->class->fields_array;
2393 unsigned int offset = sizeof(struct trace_entry);
2394
2395 for (; field->type; field++) {
2396 if (field->type == TRACE_FUNCTION_TYPE) {
2397 field->define_fields(call);
2398 break;
2399 }
2400
2401 offset = ALIGN(offset, field->align);
2402 ret = trace_define_field_ext(call, field->type, field->name,
2403 offset, field->size,
2404 field->is_signed, field->filter_type,
2405 field->len);
2406 if (WARN_ON_ONCE(ret)) {
2407 pr_err("error code is %d\n", ret);
2408 break;
2409 }
2410
2411 offset += field->size;
2412 }
2413 }
2414
2415 return ret;
2416}
2417
2418static int
2419event_create_dir(struct dentry *parent, struct trace_event_file *file)
2420{
2421 struct trace_event_call *call = file->event_call;
2422 struct trace_array *tr = file->tr;
2423 struct dentry *d_events;
2424 const char *name;
2425 int ret;
2426
2427 /*
2428 * If the trace point header did not define TRACE_SYSTEM
2429 * then the system would be called "TRACE_SYSTEM".
2430 */
2431 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
2432 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
2433 if (!d_events)
2434 return -ENOMEM;
2435 } else
2436 d_events = parent;
2437
2438 name = trace_event_name(call);
2439 file->dir = tracefs_create_dir(name, d_events);
2440 if (!file->dir) {
2441 pr_warn("Could not create tracefs '%s' directory\n", name);
2442 return -1;
2443 }
2444
2445 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
2446 trace_create_file("enable", TRACE_MODE_WRITE, file->dir, file,
2447 &ftrace_enable_fops);
2448
2449#ifdef CONFIG_PERF_EVENTS
2450 if (call->event.type && call->class->reg)
2451 trace_create_file("id", TRACE_MODE_READ, file->dir,
2452 (void *)(long)call->event.type,
2453 &ftrace_event_id_fops);
2454#endif
2455
2456 ret = event_define_fields(call);
2457 if (ret < 0) {
2458 pr_warn("Could not initialize trace point events/%s\n", name);
2459 return ret;
2460 }
2461
2462 /*
2463 * Only event directories that can be enabled should have
2464 * triggers or filters.
2465 */
2466 if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
2467 trace_create_file("filter", TRACE_MODE_WRITE, file->dir,
2468 file, &ftrace_event_filter_fops);
2469
2470 trace_create_file("trigger", TRACE_MODE_WRITE, file->dir,
2471 file, &event_trigger_fops);
2472 }
2473
2474#ifdef CONFIG_HIST_TRIGGERS
2475 trace_create_file("hist", TRACE_MODE_READ, file->dir, file,
2476 &event_hist_fops);
2477#endif
2478#ifdef CONFIG_HIST_TRIGGERS_DEBUG
2479 trace_create_file("hist_debug", TRACE_MODE_READ, file->dir, file,
2480 &event_hist_debug_fops);
2481#endif
2482 trace_create_file("format", TRACE_MODE_READ, file->dir, call,
2483 &ftrace_event_format_fops);
2484
2485#ifdef CONFIG_TRACE_EVENT_INJECT
2486 if (call->event.type && call->class->reg)
2487 trace_create_file("inject", 0200, file->dir, file,
2488 &event_inject_fops);
2489#endif
2490
2491 return 0;
2492}
2493
2494static void remove_event_from_tracers(struct trace_event_call *call)
2495{
2496 struct trace_event_file *file;
2497 struct trace_array *tr;
2498
2499 do_for_each_event_file_safe(tr, file) {
2500 if (file->event_call != call)
2501 continue;
2502
2503 remove_event_file_dir(file);
2504 /*
2505 * The do_for_each_event_file_safe() is
2506 * a double loop. After finding the call for this
2507 * trace_array, we use break to jump to the next
2508 * trace_array.
2509 */
2510 break;
2511 } while_for_each_event_file();
2512}
2513
2514static void event_remove(struct trace_event_call *call)
2515{
2516 struct trace_array *tr;
2517 struct trace_event_file *file;
2518
2519 do_for_each_event_file(tr, file) {
2520 if (file->event_call != call)
2521 continue;
2522
2523 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2524 tr->clear_trace = true;
2525
2526 ftrace_event_enable_disable(file, 0);
2527 /*
2528 * The do_for_each_event_file() is
2529 * a double loop. After finding the call for this
2530 * trace_array, we use break to jump to the next
2531 * trace_array.
2532 */
2533 break;
2534 } while_for_each_event_file();
2535
2536 if (call->event.funcs)
2537 __unregister_trace_event(&call->event);
2538 remove_event_from_tracers(call);
2539 list_del(&call->list);
2540}
2541
2542static int event_init(struct trace_event_call *call)
2543{
2544 int ret = 0;
2545 const char *name;
2546
2547 name = trace_event_name(call);
2548 if (WARN_ON(!name))
2549 return -EINVAL;
2550
2551 if (call->class->raw_init) {
2552 ret = call->class->raw_init(call);
2553 if (ret < 0 && ret != -ENOSYS)
2554 pr_warn("Could not initialize trace events/%s\n", name);
2555 }
2556
2557 return ret;
2558}
2559
2560static int
2561__register_event(struct trace_event_call *call, struct module *mod)
2562{
2563 int ret;
2564
2565 ret = event_init(call);
2566 if (ret < 0)
2567 return ret;
2568
2569 list_add(&call->list, &ftrace_events);
2570 if (call->flags & TRACE_EVENT_FL_DYNAMIC)
2571 atomic_set(&call->refcnt, 0);
2572 else
2573 call->module = mod;
2574
2575 return 0;
2576}
2577
2578static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2579{
2580 int rlen;
2581 int elen;
2582
2583 /* Find the length of the eval value as a string */
2584 elen = snprintf(ptr, 0, "%ld", map->eval_value);
2585 /* Make sure there's enough room to replace the string with the value */
2586 if (len < elen)
2587 return NULL;
2588
2589 snprintf(ptr, elen + 1, "%ld", map->eval_value);
2590
2591 /* Get the rest of the string of ptr */
2592 rlen = strlen(ptr + len);
2593 memmove(ptr + elen, ptr + len, rlen);
2594 /* Make sure we end the new string */
2595 ptr[elen + rlen] = 0;
2596
2597 return ptr + elen;
2598}
2599
2600static void update_event_printk(struct trace_event_call *call,
2601 struct trace_eval_map *map)
2602{
2603 char *ptr;
2604 int quote = 0;
2605 int len = strlen(map->eval_string);
2606
2607 for (ptr = call->print_fmt; *ptr; ptr++) {
2608 if (*ptr == '\\') {
2609 ptr++;
2610 /* paranoid */
2611 if (!*ptr)
2612 break;
2613 continue;
2614 }
2615 if (*ptr == '"') {
2616 quote ^= 1;
2617 continue;
2618 }
2619 if (quote)
2620 continue;
2621 if (isdigit(*ptr)) {
2622 /* skip numbers */
2623 do {
2624 ptr++;
2625 /* Check for alpha chars like ULL */
2626 } while (isalnum(*ptr));
2627 if (!*ptr)
2628 break;
2629 /*
2630 * A number must have some kind of delimiter after
2631 * it, and we can ignore that too.
2632 */
2633 continue;
2634 }
2635 if (isalpha(*ptr) || *ptr == '_') {
2636 if (strncmp(map->eval_string, ptr, len) == 0 &&
2637 !isalnum(ptr[len]) && ptr[len] != '_') {
2638 ptr = eval_replace(ptr, map, len);
2639 /* enum/sizeof string smaller than value */
2640 if (WARN_ON_ONCE(!ptr))
2641 return;
2642 /*
2643 * No need to decrement here, as eval_replace()
2644 * returns the pointer to the character passed
2645 * the eval, and two evals can not be placed
2646 * back to back without something in between.
2647 * We can skip that something in between.
2648 */
2649 continue;
2650 }
2651 skip_more:
2652 do {
2653 ptr++;
2654 } while (isalnum(*ptr) || *ptr == '_');
2655 if (!*ptr)
2656 break;
2657 /*
2658 * If what comes after this variable is a '.' or
2659 * '->' then we can continue to ignore that string.
2660 */
2661 if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2662 ptr += *ptr == '.' ? 1 : 2;
2663 if (!*ptr)
2664 break;
2665 goto skip_more;
2666 }
2667 /*
2668 * Once again, we can skip the delimiter that came
2669 * after the string.
2670 */
2671 continue;
2672 }
2673 }
2674}
2675
2676static void add_str_to_module(struct module *module, char *str)
2677{
2678 struct module_string *modstr;
2679
2680 modstr = kmalloc(sizeof(*modstr), GFP_KERNEL);
2681
2682 /*
2683 * If we failed to allocate memory here, then we'll just
2684 * let the str memory leak when the module is removed.
2685 * If this fails to allocate, there's worse problems than
2686 * a leaked string on module removal.
2687 */
2688 if (WARN_ON_ONCE(!modstr))
2689 return;
2690
2691 modstr->module = module;
2692 modstr->str = str;
2693
2694 list_add(&modstr->next, &module_strings);
2695}
2696
2697static void update_event_fields(struct trace_event_call *call,
2698 struct trace_eval_map *map)
2699{
2700 struct ftrace_event_field *field;
2701 struct list_head *head;
2702 char *ptr;
2703 char *str;
2704 int len = strlen(map->eval_string);
2705
2706 /* Dynamic events should never have field maps */
2707 if (WARN_ON_ONCE(call->flags & TRACE_EVENT_FL_DYNAMIC))
2708 return;
2709
2710 head = trace_get_fields(call);
2711 list_for_each_entry(field, head, link) {
2712 ptr = strchr(field->type, '[');
2713 if (!ptr)
2714 continue;
2715 ptr++;
2716
2717 if (!isalpha(*ptr) && *ptr != '_')
2718 continue;
2719
2720 if (strncmp(map->eval_string, ptr, len) != 0)
2721 continue;
2722
2723 str = kstrdup(field->type, GFP_KERNEL);
2724 if (WARN_ON_ONCE(!str))
2725 return;
2726 ptr = str + (ptr - field->type);
2727 ptr = eval_replace(ptr, map, len);
2728 /* enum/sizeof string smaller than value */
2729 if (WARN_ON_ONCE(!ptr)) {
2730 kfree(str);
2731 continue;
2732 }
2733
2734 /*
2735 * If the event is part of a module, then we need to free the string
2736 * when the module is removed. Otherwise, it will stay allocated
2737 * until a reboot.
2738 */
2739 if (call->module)
2740 add_str_to_module(call->module, str);
2741
2742 field->type = str;
2743 }
2744}
2745
2746void trace_event_eval_update(struct trace_eval_map **map, int len)
2747{
2748 struct trace_event_call *call, *p;
2749 const char *last_system = NULL;
2750 bool first = false;
2751 int last_i;
2752 int i;
2753
2754 down_write(&trace_event_sem);
2755 list_for_each_entry_safe(call, p, &ftrace_events, list) {
2756 /* events are usually grouped together with systems */
2757 if (!last_system || call->class->system != last_system) {
2758 first = true;
2759 last_i = 0;
2760 last_system = call->class->system;
2761 }
2762
2763 /*
2764 * Since calls are grouped by systems, the likelihood that the
2765 * next call in the iteration belongs to the same system as the
2766 * previous call is high. As an optimization, we skip searching
2767 * for a map[] that matches the call's system if the last call
2768 * was from the same system. That's what last_i is for. If the
2769 * call has the same system as the previous call, then last_i
2770 * will be the index of the first map[] that has a matching
2771 * system.
2772 */
2773 for (i = last_i; i < len; i++) {
2774 if (call->class->system == map[i]->system) {
2775 /* Save the first system if need be */
2776 if (first) {
2777 last_i = i;
2778 first = false;
2779 }
2780 update_event_printk(call, map[i]);
2781 update_event_fields(call, map[i]);
2782 }
2783 }
2784 }
2785 up_write(&trace_event_sem);
2786}
2787
2788static struct trace_event_file *
2789trace_create_new_event(struct trace_event_call *call,
2790 struct trace_array *tr)
2791{
2792 struct trace_pid_list *no_pid_list;
2793 struct trace_pid_list *pid_list;
2794 struct trace_event_file *file;
2795 unsigned int first;
2796
2797 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2798 if (!file)
2799 return NULL;
2800
2801 pid_list = rcu_dereference_protected(tr->filtered_pids,
2802 lockdep_is_held(&event_mutex));
2803 no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
2804 lockdep_is_held(&event_mutex));
2805
2806 if (!trace_pid_list_first(pid_list, &first) ||
2807 !trace_pid_list_first(no_pid_list, &first))
2808 file->flags |= EVENT_FILE_FL_PID_FILTER;
2809
2810 file->event_call = call;
2811 file->tr = tr;
2812 atomic_set(&file->sm_ref, 0);
2813 atomic_set(&file->tm_ref, 0);
2814 INIT_LIST_HEAD(&file->triggers);
2815 list_add(&file->list, &tr->events);
2816
2817 return file;
2818}
2819
2820#define MAX_BOOT_TRIGGERS 32
2821
2822static struct boot_triggers {
2823 const char *event;
2824 char *trigger;
2825} bootup_triggers[MAX_BOOT_TRIGGERS];
2826
2827static char bootup_trigger_buf[COMMAND_LINE_SIZE];
2828static int nr_boot_triggers;
2829
2830static __init int setup_trace_triggers(char *str)
2831{
2832 char *trigger;
2833 char *buf;
2834 int i;
2835
2836 strlcpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE);
2837 ring_buffer_expanded = true;
2838 disable_tracing_selftest("running event triggers");
2839
2840 buf = bootup_trigger_buf;
2841 for (i = 0; i < MAX_BOOT_TRIGGERS; i++) {
2842 trigger = strsep(&buf, ",");
2843 if (!trigger)
2844 break;
2845 bootup_triggers[i].event = strsep(&trigger, ".");
2846 bootup_triggers[i].trigger = strsep(&trigger, ".");
2847 if (!bootup_triggers[i].trigger)
2848 break;
2849 }
2850
2851 nr_boot_triggers = i;
2852 return 1;
2853}
2854__setup("trace_trigger=", setup_trace_triggers);
2855
2856/* Add an event to a trace directory */
2857static int
2858__trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2859{
2860 struct trace_event_file *file;
2861
2862 file = trace_create_new_event(call, tr);
2863 if (!file)
2864 return -ENOMEM;
2865
2866 if (eventdir_initialized)
2867 return event_create_dir(tr->event_dir, file);
2868 else
2869 return event_define_fields(call);
2870}
2871
2872static void trace_early_triggers(struct trace_event_file *file, const char *name)
2873{
2874 int ret;
2875 int i;
2876
2877 for (i = 0; i < nr_boot_triggers; i++) {
2878 if (strcmp(name, bootup_triggers[i].event))
2879 continue;
2880 mutex_lock(&event_mutex);
2881 ret = trigger_process_regex(file, bootup_triggers[i].trigger);
2882 mutex_unlock(&event_mutex);
2883 if (ret)
2884 pr_err("Failed to register trigger '%s' on event %s\n",
2885 bootup_triggers[i].trigger,
2886 bootup_triggers[i].event);
2887 }
2888}
2889
2890/*
2891 * Just create a descriptor for early init. A descriptor is required
2892 * for enabling events at boot. We want to enable events before
2893 * the filesystem is initialized.
2894 */
2895static int
2896__trace_early_add_new_event(struct trace_event_call *call,
2897 struct trace_array *tr)
2898{
2899 struct trace_event_file *file;
2900 int ret;
2901
2902 file = trace_create_new_event(call, tr);
2903 if (!file)
2904 return -ENOMEM;
2905
2906 ret = event_define_fields(call);
2907 if (ret)
2908 return ret;
2909
2910 trace_early_triggers(file, trace_event_name(call));
2911
2912 return 0;
2913}
2914
2915struct ftrace_module_file_ops;
2916static void __add_event_to_tracers(struct trace_event_call *call);
2917
2918/* Add an additional event_call dynamically */
2919int trace_add_event_call(struct trace_event_call *call)
2920{
2921 int ret;
2922 lockdep_assert_held(&event_mutex);
2923
2924 mutex_lock(&trace_types_lock);
2925
2926 ret = __register_event(call, NULL);
2927 if (ret >= 0)
2928 __add_event_to_tracers(call);
2929
2930 mutex_unlock(&trace_types_lock);
2931 return ret;
2932}
2933EXPORT_SYMBOL_GPL(trace_add_event_call);
2934
2935/*
2936 * Must be called under locking of trace_types_lock, event_mutex and
2937 * trace_event_sem.
2938 */
2939static void __trace_remove_event_call(struct trace_event_call *call)
2940{
2941 event_remove(call);
2942 trace_destroy_fields(call);
2943 free_event_filter(call->filter);
2944 call->filter = NULL;
2945}
2946
2947static int probe_remove_event_call(struct trace_event_call *call)
2948{
2949 struct trace_array *tr;
2950 struct trace_event_file *file;
2951
2952#ifdef CONFIG_PERF_EVENTS
2953 if (call->perf_refcount)
2954 return -EBUSY;
2955#endif
2956 do_for_each_event_file(tr, file) {
2957 if (file->event_call != call)
2958 continue;
2959 /*
2960 * We can't rely on ftrace_event_enable_disable(enable => 0)
2961 * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
2962 * TRACE_REG_UNREGISTER.
2963 */
2964 if (file->flags & EVENT_FILE_FL_ENABLED)
2965 goto busy;
2966
2967 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2968 tr->clear_trace = true;
2969 /*
2970 * The do_for_each_event_file_safe() is
2971 * a double loop. After finding the call for this
2972 * trace_array, we use break to jump to the next
2973 * trace_array.
2974 */
2975 break;
2976 } while_for_each_event_file();
2977
2978 __trace_remove_event_call(call);
2979
2980 return 0;
2981 busy:
2982 /* No need to clear the trace now */
2983 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2984 tr->clear_trace = false;
2985 }
2986 return -EBUSY;
2987}
2988
2989/* Remove an event_call */
2990int trace_remove_event_call(struct trace_event_call *call)
2991{
2992 int ret;
2993
2994 lockdep_assert_held(&event_mutex);
2995
2996 mutex_lock(&trace_types_lock);
2997 down_write(&trace_event_sem);
2998 ret = probe_remove_event_call(call);
2999 up_write(&trace_event_sem);
3000 mutex_unlock(&trace_types_lock);
3001
3002 return ret;
3003}
3004EXPORT_SYMBOL_GPL(trace_remove_event_call);
3005
3006#define for_each_event(event, start, end) \
3007 for (event = start; \
3008 (unsigned long)event < (unsigned long)end; \
3009 event++)
3010
3011#ifdef CONFIG_MODULES
3012
3013static void trace_module_add_events(struct module *mod)
3014{
3015 struct trace_event_call **call, **start, **end;
3016
3017 if (!mod->num_trace_events)
3018 return;
3019
3020 /* Don't add infrastructure for mods without tracepoints */
3021 if (trace_module_has_bad_taint(mod)) {
3022 pr_err("%s: module has bad taint, not creating trace events\n",
3023 mod->name);
3024 return;
3025 }
3026
3027 start = mod->trace_events;
3028 end = mod->trace_events + mod->num_trace_events;
3029
3030 for_each_event(call, start, end) {
3031 __register_event(*call, mod);
3032 __add_event_to_tracers(*call);
3033 }
3034}
3035
3036static void trace_module_remove_events(struct module *mod)
3037{
3038 struct trace_event_call *call, *p;
3039 struct module_string *modstr, *m;
3040
3041 down_write(&trace_event_sem);
3042 list_for_each_entry_safe(call, p, &ftrace_events, list) {
3043 if ((call->flags & TRACE_EVENT_FL_DYNAMIC) || !call->module)
3044 continue;
3045 if (call->module == mod)
3046 __trace_remove_event_call(call);
3047 }
3048 /* Check for any strings allocade for this module */
3049 list_for_each_entry_safe(modstr, m, &module_strings, next) {
3050 if (modstr->module != mod)
3051 continue;
3052 list_del(&modstr->next);
3053 kfree(modstr->str);
3054 kfree(modstr);
3055 }
3056 up_write(&trace_event_sem);
3057
3058 /*
3059 * It is safest to reset the ring buffer if the module being unloaded
3060 * registered any events that were used. The only worry is if
3061 * a new module gets loaded, and takes on the same id as the events
3062 * of this module. When printing out the buffer, traced events left
3063 * over from this module may be passed to the new module events and
3064 * unexpected results may occur.
3065 */
3066 tracing_reset_all_online_cpus_unlocked();
3067}
3068
3069static int trace_module_notify(struct notifier_block *self,
3070 unsigned long val, void *data)
3071{
3072 struct module *mod = data;
3073
3074 mutex_lock(&event_mutex);
3075 mutex_lock(&trace_types_lock);
3076 switch (val) {
3077 case MODULE_STATE_COMING:
3078 trace_module_add_events(mod);
3079 break;
3080 case MODULE_STATE_GOING:
3081 trace_module_remove_events(mod);
3082 break;
3083 }
3084 mutex_unlock(&trace_types_lock);
3085 mutex_unlock(&event_mutex);
3086
3087 return NOTIFY_OK;
3088}
3089
3090static struct notifier_block trace_module_nb = {
3091 .notifier_call = trace_module_notify,
3092 .priority = 1, /* higher than trace.c module notify */
3093};
3094#endif /* CONFIG_MODULES */
3095
3096/* Create a new event directory structure for a trace directory. */
3097static void
3098__trace_add_event_dirs(struct trace_array *tr)
3099{
3100 struct trace_event_call *call;
3101 int ret;
3102
3103 list_for_each_entry(call, &ftrace_events, list) {
3104 ret = __trace_add_new_event(call, tr);
3105 if (ret < 0)
3106 pr_warn("Could not create directory for event %s\n",
3107 trace_event_name(call));
3108 }
3109}
3110
3111/* Returns any file that matches the system and event */
3112struct trace_event_file *
3113__find_event_file(struct trace_array *tr, const char *system, const char *event)
3114{
3115 struct trace_event_file *file;
3116 struct trace_event_call *call;
3117 const char *name;
3118
3119 list_for_each_entry(file, &tr->events, list) {
3120
3121 call = file->event_call;
3122 name = trace_event_name(call);
3123
3124 if (!name || !call->class)
3125 continue;
3126
3127 if (strcmp(event, name) == 0 &&
3128 strcmp(system, call->class->system) == 0)
3129 return file;
3130 }
3131 return NULL;
3132}
3133
3134/* Returns valid trace event files that match system and event */
3135struct trace_event_file *
3136find_event_file(struct trace_array *tr, const char *system, const char *event)
3137{
3138 struct trace_event_file *file;
3139
3140 file = __find_event_file(tr, system, event);
3141 if (!file || !file->event_call->class->reg ||
3142 file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
3143 return NULL;
3144
3145 return file;
3146}
3147
3148/**
3149 * trace_get_event_file - Find and return a trace event file
3150 * @instance: The name of the trace instance containing the event
3151 * @system: The name of the system containing the event
3152 * @event: The name of the event
3153 *
3154 * Return a trace event file given the trace instance name, trace
3155 * system, and trace event name. If the instance name is NULL, it
3156 * refers to the top-level trace array.
3157 *
3158 * This function will look it up and return it if found, after calling
3159 * trace_array_get() to prevent the instance from going away, and
3160 * increment the event's module refcount to prevent it from being
3161 * removed.
3162 *
3163 * To release the file, call trace_put_event_file(), which will call
3164 * trace_array_put() and decrement the event's module refcount.
3165 *
3166 * Return: The trace event on success, ERR_PTR otherwise.
3167 */
3168struct trace_event_file *trace_get_event_file(const char *instance,
3169 const char *system,
3170 const char *event)
3171{
3172 struct trace_array *tr = top_trace_array();
3173 struct trace_event_file *file = NULL;
3174 int ret = -EINVAL;
3175
3176 if (instance) {
3177 tr = trace_array_find_get(instance);
3178 if (!tr)
3179 return ERR_PTR(-ENOENT);
3180 } else {
3181 ret = trace_array_get(tr);
3182 if (ret)
3183 return ERR_PTR(ret);
3184 }
3185
3186 mutex_lock(&event_mutex);
3187
3188 file = find_event_file(tr, system, event);
3189 if (!file) {
3190 trace_array_put(tr);
3191 ret = -EINVAL;
3192 goto out;
3193 }
3194
3195 /* Don't let event modules unload while in use */
3196 ret = trace_event_try_get_ref(file->event_call);
3197 if (!ret) {
3198 trace_array_put(tr);
3199 ret = -EBUSY;
3200 goto out;
3201 }
3202
3203 ret = 0;
3204 out:
3205 mutex_unlock(&event_mutex);
3206
3207 if (ret)
3208 file = ERR_PTR(ret);
3209
3210 return file;
3211}
3212EXPORT_SYMBOL_GPL(trace_get_event_file);
3213
3214/**
3215 * trace_put_event_file - Release a file from trace_get_event_file()
3216 * @file: The trace event file
3217 *
3218 * If a file was retrieved using trace_get_event_file(), this should
3219 * be called when it's no longer needed. It will cancel the previous
3220 * trace_array_get() called by that function, and decrement the
3221 * event's module refcount.
3222 */
3223void trace_put_event_file(struct trace_event_file *file)
3224{
3225 mutex_lock(&event_mutex);
3226 trace_event_put_ref(file->event_call);
3227 mutex_unlock(&event_mutex);
3228
3229 trace_array_put(file->tr);
3230}
3231EXPORT_SYMBOL_GPL(trace_put_event_file);
3232
3233#ifdef CONFIG_DYNAMIC_FTRACE
3234
3235/* Avoid typos */
3236#define ENABLE_EVENT_STR "enable_event"
3237#define DISABLE_EVENT_STR "disable_event"
3238
3239struct event_probe_data {
3240 struct trace_event_file *file;
3241 unsigned long count;
3242 int ref;
3243 bool enable;
3244};
3245
3246static void update_event_probe(struct event_probe_data *data)
3247{
3248 if (data->enable)
3249 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3250 else
3251 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3252}
3253
3254static void
3255event_enable_probe(unsigned long ip, unsigned long parent_ip,
3256 struct trace_array *tr, struct ftrace_probe_ops *ops,
3257 void *data)
3258{
3259 struct ftrace_func_mapper *mapper = data;
3260 struct event_probe_data *edata;
3261 void **pdata;
3262
3263 pdata = ftrace_func_mapper_find_ip(mapper, ip);
3264 if (!pdata || !*pdata)
3265 return;
3266
3267 edata = *pdata;
3268 update_event_probe(edata);
3269}
3270
3271static void
3272event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
3273 struct trace_array *tr, struct ftrace_probe_ops *ops,
3274 void *data)
3275{
3276 struct ftrace_func_mapper *mapper = data;
3277 struct event_probe_data *edata;
3278 void **pdata;
3279
3280 pdata = ftrace_func_mapper_find_ip(mapper, ip);
3281 if (!pdata || !*pdata)
3282 return;
3283
3284 edata = *pdata;
3285
3286 if (!edata->count)
3287 return;
3288
3289 /* Skip if the event is in a state we want to switch to */
3290 if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
3291 return;
3292
3293 if (edata->count != -1)
3294 (edata->count)--;
3295
3296 update_event_probe(edata);
3297}
3298
3299static int
3300event_enable_print(struct seq_file *m, unsigned long ip,
3301 struct ftrace_probe_ops *ops, void *data)
3302{
3303 struct ftrace_func_mapper *mapper = data;
3304 struct event_probe_data *edata;
3305 void **pdata;
3306
3307 pdata = ftrace_func_mapper_find_ip(mapper, ip);
3308
3309 if (WARN_ON_ONCE(!pdata || !*pdata))
3310 return 0;
3311
3312 edata = *pdata;
3313
3314 seq_printf(m, "%ps:", (void *)ip);
3315
3316 seq_printf(m, "%s:%s:%s",
3317 edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
3318 edata->file->event_call->class->system,
3319 trace_event_name(edata->file->event_call));
3320
3321 if (edata->count == -1)
3322 seq_puts(m, ":unlimited\n");
3323 else
3324 seq_printf(m, ":count=%ld\n", edata->count);
3325
3326 return 0;
3327}
3328
3329static int
3330event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
3331 unsigned long ip, void *init_data, void **data)
3332{
3333 struct ftrace_func_mapper *mapper = *data;
3334 struct event_probe_data *edata = init_data;
3335 int ret;
3336
3337 if (!mapper) {
3338 mapper = allocate_ftrace_func_mapper();
3339 if (!mapper)
3340 return -ENODEV;
3341 *data = mapper;
3342 }
3343
3344 ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
3345 if (ret < 0)
3346 return ret;
3347
3348 edata->ref++;
3349
3350 return 0;
3351}
3352
3353static int free_probe_data(void *data)
3354{
3355 struct event_probe_data *edata = data;
3356
3357 edata->ref--;
3358 if (!edata->ref) {
3359 /* Remove the SOFT_MODE flag */
3360 __ftrace_event_enable_disable(edata->file, 0, 1);
3361 trace_event_put_ref(edata->file->event_call);
3362 kfree(edata);
3363 }
3364 return 0;
3365}
3366
3367static void
3368event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
3369 unsigned long ip, void *data)
3370{
3371 struct ftrace_func_mapper *mapper = data;
3372 struct event_probe_data *edata;
3373
3374 if (!ip) {
3375 if (!mapper)
3376 return;
3377 free_ftrace_func_mapper(mapper, free_probe_data);
3378 return;
3379 }
3380
3381 edata = ftrace_func_mapper_remove_ip(mapper, ip);
3382
3383 if (WARN_ON_ONCE(!edata))
3384 return;
3385
3386 if (WARN_ON_ONCE(edata->ref <= 0))
3387 return;
3388
3389 free_probe_data(edata);
3390}
3391
3392static struct ftrace_probe_ops event_enable_probe_ops = {
3393 .func = event_enable_probe,
3394 .print = event_enable_print,
3395 .init = event_enable_init,
3396 .free = event_enable_free,
3397};
3398
3399static struct ftrace_probe_ops event_enable_count_probe_ops = {
3400 .func = event_enable_count_probe,
3401 .print = event_enable_print,
3402 .init = event_enable_init,
3403 .free = event_enable_free,
3404};
3405
3406static struct ftrace_probe_ops event_disable_probe_ops = {
3407 .func = event_enable_probe,
3408 .print = event_enable_print,
3409 .init = event_enable_init,
3410 .free = event_enable_free,
3411};
3412
3413static struct ftrace_probe_ops event_disable_count_probe_ops = {
3414 .func = event_enable_count_probe,
3415 .print = event_enable_print,
3416 .init = event_enable_init,
3417 .free = event_enable_free,
3418};
3419
3420static int
3421event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
3422 char *glob, char *cmd, char *param, int enabled)
3423{
3424 struct trace_event_file *file;
3425 struct ftrace_probe_ops *ops;
3426 struct event_probe_data *data;
3427 const char *system;
3428 const char *event;
3429 char *number;
3430 bool enable;
3431 int ret;
3432
3433 if (!tr)
3434 return -ENODEV;
3435
3436 /* hash funcs only work with set_ftrace_filter */
3437 if (!enabled || !param)
3438 return -EINVAL;
3439
3440 system = strsep(¶m, ":");
3441 if (!param)
3442 return -EINVAL;
3443
3444 event = strsep(¶m, ":");
3445
3446 mutex_lock(&event_mutex);
3447
3448 ret = -EINVAL;
3449 file = find_event_file(tr, system, event);
3450 if (!file)
3451 goto out;
3452
3453 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
3454
3455 if (enable)
3456 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
3457 else
3458 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
3459
3460 if (glob[0] == '!') {
3461 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
3462 goto out;
3463 }
3464
3465 ret = -ENOMEM;
3466
3467 data = kzalloc(sizeof(*data), GFP_KERNEL);
3468 if (!data)
3469 goto out;
3470
3471 data->enable = enable;
3472 data->count = -1;
3473 data->file = file;
3474
3475 if (!param)
3476 goto out_reg;
3477
3478 number = strsep(¶m, ":");
3479
3480 ret = -EINVAL;
3481 if (!strlen(number))
3482 goto out_free;
3483
3484 /*
3485 * We use the callback data field (which is a pointer)
3486 * as our counter.
3487 */
3488 ret = kstrtoul(number, 0, &data->count);
3489 if (ret)
3490 goto out_free;
3491
3492 out_reg:
3493 /* Don't let event modules unload while probe registered */
3494 ret = trace_event_try_get_ref(file->event_call);
3495 if (!ret) {
3496 ret = -EBUSY;
3497 goto out_free;
3498 }
3499
3500 ret = __ftrace_event_enable_disable(file, 1, 1);
3501 if (ret < 0)
3502 goto out_put;
3503
3504 ret = register_ftrace_function_probe(glob, tr, ops, data);
3505 /*
3506 * The above returns on success the # of functions enabled,
3507 * but if it didn't find any functions it returns zero.
3508 * Consider no functions a failure too.
3509 */
3510 if (!ret) {
3511 ret = -ENOENT;
3512 goto out_disable;
3513 } else if (ret < 0)
3514 goto out_disable;
3515 /* Just return zero, not the number of enabled functions */
3516 ret = 0;
3517 out:
3518 mutex_unlock(&event_mutex);
3519 return ret;
3520
3521 out_disable:
3522 __ftrace_event_enable_disable(file, 0, 1);
3523 out_put:
3524 trace_event_put_ref(file->event_call);
3525 out_free:
3526 kfree(data);
3527 goto out;
3528}
3529
3530static struct ftrace_func_command event_enable_cmd = {
3531 .name = ENABLE_EVENT_STR,
3532 .func = event_enable_func,
3533};
3534
3535static struct ftrace_func_command event_disable_cmd = {
3536 .name = DISABLE_EVENT_STR,
3537 .func = event_enable_func,
3538};
3539
3540static __init int register_event_cmds(void)
3541{
3542 int ret;
3543
3544 ret = register_ftrace_command(&event_enable_cmd);
3545 if (WARN_ON(ret < 0))
3546 return ret;
3547 ret = register_ftrace_command(&event_disable_cmd);
3548 if (WARN_ON(ret < 0))
3549 unregister_ftrace_command(&event_enable_cmd);
3550 return ret;
3551}
3552#else
3553static inline int register_event_cmds(void) { return 0; }
3554#endif /* CONFIG_DYNAMIC_FTRACE */
3555
3556/*
3557 * The top level array and trace arrays created by boot-time tracing
3558 * have already had its trace_event_file descriptors created in order
3559 * to allow for early events to be recorded.
3560 * This function is called after the tracefs has been initialized,
3561 * and we now have to create the files associated to the events.
3562 */
3563static void __trace_early_add_event_dirs(struct trace_array *tr)
3564{
3565 struct trace_event_file *file;
3566 int ret;
3567
3568
3569 list_for_each_entry(file, &tr->events, list) {
3570 ret = event_create_dir(tr->event_dir, file);
3571 if (ret < 0)
3572 pr_warn("Could not create directory for event %s\n",
3573 trace_event_name(file->event_call));
3574 }
3575}
3576
3577/*
3578 * For early boot up, the top trace array and the trace arrays created
3579 * by boot-time tracing require to have a list of events that can be
3580 * enabled. This must be done before the filesystem is set up in order
3581 * to allow events to be traced early.
3582 */
3583void __trace_early_add_events(struct trace_array *tr)
3584{
3585 struct trace_event_call *call;
3586 int ret;
3587
3588 list_for_each_entry(call, &ftrace_events, list) {
3589 /* Early boot up should not have any modules loaded */
3590 if (!(call->flags & TRACE_EVENT_FL_DYNAMIC) &&
3591 WARN_ON_ONCE(call->module))
3592 continue;
3593
3594 ret = __trace_early_add_new_event(call, tr);
3595 if (ret < 0)
3596 pr_warn("Could not create early event %s\n",
3597 trace_event_name(call));
3598 }
3599}
3600
3601/* Remove the event directory structure for a trace directory. */
3602static void
3603__trace_remove_event_dirs(struct trace_array *tr)
3604{
3605 struct trace_event_file *file, *next;
3606
3607 list_for_each_entry_safe(file, next, &tr->events, list)
3608 remove_event_file_dir(file);
3609}
3610
3611static void __add_event_to_tracers(struct trace_event_call *call)
3612{
3613 struct trace_array *tr;
3614
3615 list_for_each_entry(tr, &ftrace_trace_arrays, list)
3616 __trace_add_new_event(call, tr);
3617}
3618
3619extern struct trace_event_call *__start_ftrace_events[];
3620extern struct trace_event_call *__stop_ftrace_events[];
3621
3622static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
3623
3624static __init int setup_trace_event(char *str)
3625{
3626 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
3627 ring_buffer_expanded = true;
3628 disable_tracing_selftest("running event tracing");
3629
3630 return 1;
3631}
3632__setup("trace_event=", setup_trace_event);
3633
3634/* Expects to have event_mutex held when called */
3635static int
3636create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
3637{
3638 struct dentry *d_events;
3639 struct dentry *entry;
3640
3641 entry = trace_create_file("set_event", TRACE_MODE_WRITE, parent,
3642 tr, &ftrace_set_event_fops);
3643 if (!entry)
3644 return -ENOMEM;
3645
3646 d_events = tracefs_create_dir("events", parent);
3647 if (!d_events) {
3648 pr_warn("Could not create tracefs 'events' directory\n");
3649 return -ENOMEM;
3650 }
3651
3652 entry = trace_create_file("enable", TRACE_MODE_WRITE, d_events,
3653 tr, &ftrace_tr_enable_fops);
3654 if (!entry)
3655 return -ENOMEM;
3656
3657 /* There are not as crucial, just warn if they are not created */
3658
3659 trace_create_file("set_event_pid", TRACE_MODE_WRITE, parent,
3660 tr, &ftrace_set_event_pid_fops);
3661
3662 trace_create_file("set_event_notrace_pid",
3663 TRACE_MODE_WRITE, parent, tr,
3664 &ftrace_set_event_notrace_pid_fops);
3665
3666 /* ring buffer internal formats */
3667 trace_create_file("header_page", TRACE_MODE_READ, d_events,
3668 ring_buffer_print_page_header,
3669 &ftrace_show_header_fops);
3670
3671 trace_create_file("header_event", TRACE_MODE_READ, d_events,
3672 ring_buffer_print_entry_header,
3673 &ftrace_show_header_fops);
3674
3675 tr->event_dir = d_events;
3676
3677 return 0;
3678}
3679
3680/**
3681 * event_trace_add_tracer - add a instance of a trace_array to events
3682 * @parent: The parent dentry to place the files/directories for events in
3683 * @tr: The trace array associated with these events
3684 *
3685 * When a new instance is created, it needs to set up its events
3686 * directory, as well as other files associated with events. It also
3687 * creates the event hierarchy in the @parent/events directory.
3688 *
3689 * Returns 0 on success.
3690 *
3691 * Must be called with event_mutex held.
3692 */
3693int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
3694{
3695 int ret;
3696
3697 lockdep_assert_held(&event_mutex);
3698
3699 ret = create_event_toplevel_files(parent, tr);
3700 if (ret)
3701 goto out;
3702
3703 down_write(&trace_event_sem);
3704 /* If tr already has the event list, it is initialized in early boot. */
3705 if (unlikely(!list_empty(&tr->events)))
3706 __trace_early_add_event_dirs(tr);
3707 else
3708 __trace_add_event_dirs(tr);
3709 up_write(&trace_event_sem);
3710
3711 out:
3712 return ret;
3713}
3714
3715/*
3716 * The top trace array already had its file descriptors created.
3717 * Now the files themselves need to be created.
3718 */
3719static __init int
3720early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
3721{
3722 int ret;
3723
3724 mutex_lock(&event_mutex);
3725
3726 ret = create_event_toplevel_files(parent, tr);
3727 if (ret)
3728 goto out_unlock;
3729
3730 down_write(&trace_event_sem);
3731 __trace_early_add_event_dirs(tr);
3732 up_write(&trace_event_sem);
3733
3734 out_unlock:
3735 mutex_unlock(&event_mutex);
3736
3737 return ret;
3738}
3739
3740/* Must be called with event_mutex held */
3741int event_trace_del_tracer(struct trace_array *tr)
3742{
3743 lockdep_assert_held(&event_mutex);
3744
3745 /* Disable any event triggers and associated soft-disabled events */
3746 clear_event_triggers(tr);
3747
3748 /* Clear the pid list */
3749 __ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
3750
3751 /* Disable any running events */
3752 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3753
3754 /* Make sure no more events are being executed */
3755 tracepoint_synchronize_unregister();
3756
3757 down_write(&trace_event_sem);
3758 __trace_remove_event_dirs(tr);
3759 tracefs_remove(tr->event_dir);
3760 up_write(&trace_event_sem);
3761
3762 tr->event_dir = NULL;
3763
3764 return 0;
3765}
3766
3767static __init int event_trace_memsetup(void)
3768{
3769 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3770 file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3771 return 0;
3772}
3773
3774static __init void
3775early_enable_events(struct trace_array *tr, bool disable_first)
3776{
3777 char *buf = bootup_event_buf;
3778 char *token;
3779 int ret;
3780
3781 while (true) {
3782 token = strsep(&buf, ",");
3783
3784 if (!token)
3785 break;
3786
3787 if (*token) {
3788 /* Restarting syscalls requires that we stop them first */
3789 if (disable_first)
3790 ftrace_set_clr_event(tr, token, 0);
3791
3792 ret = ftrace_set_clr_event(tr, token, 1);
3793 if (ret)
3794 pr_warn("Failed to enable trace event: %s\n", token);
3795 }
3796
3797 /* Put back the comma to allow this to be called again */
3798 if (buf)
3799 *(buf - 1) = ',';
3800 }
3801}
3802
3803static __init int event_trace_enable(void)
3804{
3805 struct trace_array *tr = top_trace_array();
3806 struct trace_event_call **iter, *call;
3807 int ret;
3808
3809 if (!tr)
3810 return -ENODEV;
3811
3812 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3813
3814 call = *iter;
3815 ret = event_init(call);
3816 if (!ret)
3817 list_add(&call->list, &ftrace_events);
3818 }
3819
3820 register_trigger_cmds();
3821
3822 /*
3823 * We need the top trace array to have a working set of trace
3824 * points at early init, before the debug files and directories
3825 * are created. Create the file entries now, and attach them
3826 * to the actual file dentries later.
3827 */
3828 __trace_early_add_events(tr);
3829
3830 early_enable_events(tr, false);
3831
3832 trace_printk_start_comm();
3833
3834 register_event_cmds();
3835
3836
3837 return 0;
3838}
3839
3840/*
3841 * event_trace_enable() is called from trace_event_init() first to
3842 * initialize events and perhaps start any events that are on the
3843 * command line. Unfortunately, there are some events that will not
3844 * start this early, like the system call tracepoints that need
3845 * to set the %SYSCALL_WORK_SYSCALL_TRACEPOINT flag of pid 1. But
3846 * event_trace_enable() is called before pid 1 starts, and this flag
3847 * is never set, making the syscall tracepoint never get reached, but
3848 * the event is enabled regardless (and not doing anything).
3849 */
3850static __init int event_trace_enable_again(void)
3851{
3852 struct trace_array *tr;
3853
3854 tr = top_trace_array();
3855 if (!tr)
3856 return -ENODEV;
3857
3858 early_enable_events(tr, true);
3859
3860 return 0;
3861}
3862
3863early_initcall(event_trace_enable_again);
3864
3865/* Init fields which doesn't related to the tracefs */
3866static __init int event_trace_init_fields(void)
3867{
3868 if (trace_define_generic_fields())
3869 pr_warn("tracing: Failed to allocated generic fields");
3870
3871 if (trace_define_common_fields())
3872 pr_warn("tracing: Failed to allocate common fields");
3873
3874 return 0;
3875}
3876
3877__init int event_trace_init(void)
3878{
3879 struct trace_array *tr;
3880 int ret;
3881
3882 tr = top_trace_array();
3883 if (!tr)
3884 return -ENODEV;
3885
3886 trace_create_file("available_events", TRACE_MODE_READ,
3887 NULL, tr, &ftrace_avail_fops);
3888
3889 ret = early_event_add_tracer(NULL, tr);
3890 if (ret)
3891 return ret;
3892
3893#ifdef CONFIG_MODULES
3894 ret = register_module_notifier(&trace_module_nb);
3895 if (ret)
3896 pr_warn("Failed to register trace events module notifier\n");
3897#endif
3898
3899 eventdir_initialized = true;
3900
3901 return 0;
3902}
3903
3904void __init trace_event_init(void)
3905{
3906 event_trace_memsetup();
3907 init_ftrace_syscalls();
3908 event_trace_enable();
3909 event_trace_init_fields();
3910}
3911
3912#ifdef CONFIG_EVENT_TRACE_STARTUP_TEST
3913
3914static DEFINE_SPINLOCK(test_spinlock);
3915static DEFINE_SPINLOCK(test_spinlock_irq);
3916static DEFINE_MUTEX(test_mutex);
3917
3918static __init void test_work(struct work_struct *dummy)
3919{
3920 spin_lock(&test_spinlock);
3921 spin_lock_irq(&test_spinlock_irq);
3922 udelay(1);
3923 spin_unlock_irq(&test_spinlock_irq);
3924 spin_unlock(&test_spinlock);
3925
3926 mutex_lock(&test_mutex);
3927 msleep(1);
3928 mutex_unlock(&test_mutex);
3929}
3930
3931static __init int event_test_thread(void *unused)
3932{
3933 void *test_malloc;
3934
3935 test_malloc = kmalloc(1234, GFP_KERNEL);
3936 if (!test_malloc)
3937 pr_info("failed to kmalloc\n");
3938
3939 schedule_on_each_cpu(test_work);
3940
3941 kfree(test_malloc);
3942
3943 set_current_state(TASK_INTERRUPTIBLE);
3944 while (!kthread_should_stop()) {
3945 schedule();
3946 set_current_state(TASK_INTERRUPTIBLE);
3947 }
3948 __set_current_state(TASK_RUNNING);
3949
3950 return 0;
3951}
3952
3953/*
3954 * Do various things that may trigger events.
3955 */
3956static __init void event_test_stuff(void)
3957{
3958 struct task_struct *test_thread;
3959
3960 test_thread = kthread_run(event_test_thread, NULL, "test-events");
3961 msleep(1);
3962 kthread_stop(test_thread);
3963}
3964
3965/*
3966 * For every trace event defined, we will test each trace point separately,
3967 * and then by groups, and finally all trace points.
3968 */
3969static __init void event_trace_self_tests(void)
3970{
3971 struct trace_subsystem_dir *dir;
3972 struct trace_event_file *file;
3973 struct trace_event_call *call;
3974 struct event_subsystem *system;
3975 struct trace_array *tr;
3976 int ret;
3977
3978 tr = top_trace_array();
3979 if (!tr)
3980 return;
3981
3982 pr_info("Running tests on trace events:\n");
3983
3984 list_for_each_entry(file, &tr->events, list) {
3985
3986 call = file->event_call;
3987
3988 /* Only test those that have a probe */
3989 if (!call->class || !call->class->probe)
3990 continue;
3991
3992/*
3993 * Testing syscall events here is pretty useless, but
3994 * we still do it if configured. But this is time consuming.
3995 * What we really need is a user thread to perform the
3996 * syscalls as we test.
3997 */
3998#ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
3999 if (call->class->system &&
4000 strcmp(call->class->system, "syscalls") == 0)
4001 continue;
4002#endif
4003
4004 pr_info("Testing event %s: ", trace_event_name(call));
4005
4006 /*
4007 * If an event is already enabled, someone is using
4008 * it and the self test should not be on.
4009 */
4010 if (file->flags & EVENT_FILE_FL_ENABLED) {
4011 pr_warn("Enabled event during self test!\n");
4012 WARN_ON_ONCE(1);
4013 continue;
4014 }
4015
4016 ftrace_event_enable_disable(file, 1);
4017 event_test_stuff();
4018 ftrace_event_enable_disable(file, 0);
4019
4020 pr_cont("OK\n");
4021 }
4022
4023 /* Now test at the sub system level */
4024
4025 pr_info("Running tests on trace event systems:\n");
4026
4027 list_for_each_entry(dir, &tr->systems, list) {
4028
4029 system = dir->subsystem;
4030
4031 /* the ftrace system is special, skip it */
4032 if (strcmp(system->name, "ftrace") == 0)
4033 continue;
4034
4035 pr_info("Testing event system %s: ", system->name);
4036
4037 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
4038 if (WARN_ON_ONCE(ret)) {
4039 pr_warn("error enabling system %s\n",
4040 system->name);
4041 continue;
4042 }
4043
4044 event_test_stuff();
4045
4046 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
4047 if (WARN_ON_ONCE(ret)) {
4048 pr_warn("error disabling system %s\n",
4049 system->name);
4050 continue;
4051 }
4052
4053 pr_cont("OK\n");
4054 }
4055
4056 /* Test with all events enabled */
4057
4058 pr_info("Running tests on all trace events:\n");
4059 pr_info("Testing all events: ");
4060
4061 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
4062 if (WARN_ON_ONCE(ret)) {
4063 pr_warn("error enabling all events\n");
4064 return;
4065 }
4066
4067 event_test_stuff();
4068
4069 /* reset sysname */
4070 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
4071 if (WARN_ON_ONCE(ret)) {
4072 pr_warn("error disabling all events\n");
4073 return;
4074 }
4075
4076 pr_cont("OK\n");
4077}
4078
4079#ifdef CONFIG_FUNCTION_TRACER
4080
4081static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
4082
4083static struct trace_event_file event_trace_file __initdata;
4084
4085static void __init
4086function_test_events_call(unsigned long ip, unsigned long parent_ip,
4087 struct ftrace_ops *op, struct ftrace_regs *regs)
4088{
4089 struct trace_buffer *buffer;
4090 struct ring_buffer_event *event;
4091 struct ftrace_entry *entry;
4092 unsigned int trace_ctx;
4093 long disabled;
4094 int cpu;
4095
4096 trace_ctx = tracing_gen_ctx();
4097 preempt_disable_notrace();
4098 cpu = raw_smp_processor_id();
4099 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
4100
4101 if (disabled != 1)
4102 goto out;
4103
4104 event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
4105 TRACE_FN, sizeof(*entry),
4106 trace_ctx);
4107 if (!event)
4108 goto out;
4109 entry = ring_buffer_event_data(event);
4110 entry->ip = ip;
4111 entry->parent_ip = parent_ip;
4112
4113 event_trigger_unlock_commit(&event_trace_file, buffer, event,
4114 entry, trace_ctx);
4115 out:
4116 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
4117 preempt_enable_notrace();
4118}
4119
4120static struct ftrace_ops trace_ops __initdata =
4121{
4122 .func = function_test_events_call,
4123};
4124
4125static __init void event_trace_self_test_with_function(void)
4126{
4127 int ret;
4128
4129 event_trace_file.tr = top_trace_array();
4130 if (WARN_ON(!event_trace_file.tr))
4131 return;
4132
4133 ret = register_ftrace_function(&trace_ops);
4134 if (WARN_ON(ret < 0)) {
4135 pr_info("Failed to enable function tracer for event tests\n");
4136 return;
4137 }
4138 pr_info("Running tests again, along with the function tracer\n");
4139 event_trace_self_tests();
4140 unregister_ftrace_function(&trace_ops);
4141}
4142#else
4143static __init void event_trace_self_test_with_function(void)
4144{
4145}
4146#endif
4147
4148static __init int event_trace_self_tests_init(void)
4149{
4150 if (!tracing_selftest_disabled) {
4151 event_trace_self_tests();
4152 event_trace_self_test_with_function();
4153 }
4154
4155 return 0;
4156}
4157
4158late_initcall(event_trace_self_tests_init);
4159
4160#endif