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[cor.git] / kernel / trace / trace_events.c
blobc6de3cebc127fe83842887a300cae6d44dcd8c98
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
28 #include <asm/setup.h>
29
30 #include "trace_output.h"
31
32 #undef TRACE_SYSTEM
33 #define TRACE_SYSTEM "TRACE_SYSTEM"
34
35 DEFINE_MUTEX(event_mutex);
36
37 LIST_HEAD(ftrace_events);
38 static LIST_HEAD(ftrace_generic_fields);
39 static LIST_HEAD(ftrace_common_fields);
40
41 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
42
43 static struct kmem_cache *field_cachep;
44 static struct kmem_cache *file_cachep;
45
46 static inline int system_refcount(struct event_subsystem *system)
47 {
48 return system->ref_count;
49 }
50
51 static int system_refcount_inc(struct event_subsystem *system)
52 {
53 return system->ref_count++;
54 }
55
56 static int system_refcount_dec(struct event_subsystem *system)
57 {
58 return --system->ref_count;
59 }
60
61 /* Double loops, do not use break, only goto's work */
62 #define do_for_each_event_file(tr, file) \
63 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
64 list_for_each_entry(file, &tr->events, list)
65
66 #define do_for_each_event_file_safe(tr, file) \
67 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
68 struct trace_event_file *___n; \
69 list_for_each_entry_safe(file, ___n, &tr->events, list)
70
71 #define while_for_each_event_file() \
72 }
73
74 static struct ftrace_event_field *
75 __find_event_field(struct list_head *head, char *name)
76 {
77 struct ftrace_event_field *field;
78
79 list_for_each_entry(field, head, link) {
80 if (!strcmp(field->name, name))
81 return field;
82 }
83
84 return NULL;
85 }
86
87 struct ftrace_event_field *
88 trace_find_event_field(struct trace_event_call *call, char *name)
89 {
90 struct ftrace_event_field *field;
91 struct list_head *head;
92
93 head = trace_get_fields(call);
94 field = __find_event_field(head, name);
95 if (field)
96 return field;
97
98 field = __find_event_field(&ftrace_generic_fields, name);
99 if (field)
100 return field;
101
102 return __find_event_field(&ftrace_common_fields, name);
103 }
104
105 static int __trace_define_field(struct list_head *head, const char *type,
106 const char *name, int offset, int size,
107 int is_signed, int filter_type)
108 {
109 struct ftrace_event_field *field;
110
111 field = kmem_cache_alloc(field_cachep, GFP_TRACE);
112 if (!field)
113 return -ENOMEM;
114
115 field->name = name;
116 field->type = type;
117
118 if (filter_type == FILTER_OTHER)
119 field->filter_type = filter_assign_type(type);
120 else
121 field->filter_type = filter_type;
122
123 field->offset = offset;
124 field->size = size;
125 field->is_signed = is_signed;
126
127 list_add(&field->link, head);
128
129 return 0;
130 }
131
132 int trace_define_field(struct trace_event_call *call, const char *type,
133 const char *name, int offset, int size, int is_signed,
134 int filter_type)
135 {
136 struct list_head *head;
137
138 if (WARN_ON(!call->class))
139 return 0;
140
141 head = trace_get_fields(call);
142 return __trace_define_field(head, type, name, offset, size,
143 is_signed, filter_type);
144 }
145 EXPORT_SYMBOL_GPL(trace_define_field);
146
147 #define __generic_field(type, item, filter_type) \
148 ret = __trace_define_field(&ftrace_generic_fields, #type, \
149 #item, 0, 0, is_signed_type(type), \
150 filter_type); \
151 if (ret) \
152 return ret;
153
154 #define __common_field(type, item) \
155 ret = __trace_define_field(&ftrace_common_fields, #type, \
156 "common_" #item, \
157 offsetof(typeof(ent), item), \
158 sizeof(ent.item), \
159 is_signed_type(type), FILTER_OTHER); \
160 if (ret) \
161 return ret;
162
163 static int trace_define_generic_fields(void)
164 {
165 int ret;
166
167 __generic_field(int, CPU, FILTER_CPU);
168 __generic_field(int, cpu, FILTER_CPU);
169 __generic_field(char *, COMM, FILTER_COMM);
170 __generic_field(char *, comm, FILTER_COMM);
171
172 return ret;
173 }
174
175 static int trace_define_common_fields(void)
176 {
177 int ret;
178 struct trace_entry ent;
179
180 __common_field(unsigned short, type);
181 __common_field(unsigned char, flags);
182 __common_field(unsigned char, preempt_count);
183 __common_field(int, pid);
184
185 return ret;
186 }
187
188 static void trace_destroy_fields(struct trace_event_call *call)
189 {
190 struct ftrace_event_field *field, *next;
191 struct list_head *head;
192
193 head = trace_get_fields(call);
194 list_for_each_entry_safe(field, next, head, link) {
195 list_del(&field->link);
196 kmem_cache_free(field_cachep, field);
197 }
198 }
199
200 /*
201 * run-time version of trace_event_get_offsets_<call>() that returns the last
202 * accessible offset of trace fields excluding __dynamic_array bytes
203 */
204 int trace_event_get_offsets(struct trace_event_call *call)
205 {
206 struct ftrace_event_field *tail;
207 struct list_head *head;
208
209 head = trace_get_fields(call);
210 /*
211 * head->next points to the last field with the largest offset,
212 * since it was added last by trace_define_field()
213 */
214 tail = list_first_entry(head, struct ftrace_event_field, link);
215 return tail->offset + tail->size;
216 }
217
218 int trace_event_raw_init(struct trace_event_call *call)
219 {
220 int id;
221
222 id = register_trace_event(&call->event);
223 if (!id)
224 return -ENODEV;
225
226 return 0;
227 }
228 EXPORT_SYMBOL_GPL(trace_event_raw_init);
229
230 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
231 {
232 struct trace_array *tr = trace_file->tr;
233 struct trace_array_cpu *data;
234 struct trace_pid_list *pid_list;
235
236 pid_list = rcu_dereference_raw(tr->filtered_pids);
237 if (!pid_list)
238 return false;
239
240 data = this_cpu_ptr(tr->trace_buffer.data);
241
242 return data->ignore_pid;
243 }
244 EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
245
246 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
247 struct trace_event_file *trace_file,
248 unsigned long len)
249 {
250 struct trace_event_call *event_call = trace_file->event_call;
251
252 if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
253 trace_event_ignore_this_pid(trace_file))
254 return NULL;
255
256 local_save_flags(fbuffer->flags);
257 fbuffer->pc = preempt_count();
258 /*
259 * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
260 * preemption (adding one to the preempt_count). Since we are
261 * interested in the preempt_count at the time the tracepoint was
262 * hit, we need to subtract one to offset the increment.
263 */
264 if (IS_ENABLED(CONFIG_PREEMPTION))
265 fbuffer->pc--;
266 fbuffer->trace_file = trace_file;
267
268 fbuffer->event =
269 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
270 event_call->event.type, len,
271 fbuffer->flags, fbuffer->pc);
272 if (!fbuffer->event)
273 return NULL;
274
275 fbuffer->entry = ring_buffer_event_data(fbuffer->event);
276 return fbuffer->entry;
277 }
278 EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
279
280 int trace_event_reg(struct trace_event_call *call,
281 enum trace_reg type, void *data)
282 {
283 struct trace_event_file *file = data;
284
285 WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
286 switch (type) {
287 case TRACE_REG_REGISTER:
288 return tracepoint_probe_register(call->tp,
289 call->class->probe,
290 file);
291 case TRACE_REG_UNREGISTER:
292 tracepoint_probe_unregister(call->tp,
293 call->class->probe,
294 file);
295 return 0;
296
297 #ifdef CONFIG_PERF_EVENTS
298 case TRACE_REG_PERF_REGISTER:
299 return tracepoint_probe_register(call->tp,
300 call->class->perf_probe,
301 call);
302 case TRACE_REG_PERF_UNREGISTER:
303 tracepoint_probe_unregister(call->tp,
304 call->class->perf_probe,
305 call);
306 return 0;
307 case TRACE_REG_PERF_OPEN:
308 case TRACE_REG_PERF_CLOSE:
309 case TRACE_REG_PERF_ADD:
310 case TRACE_REG_PERF_DEL:
311 return 0;
312 #endif
313 }
314 return 0;
315 }
316 EXPORT_SYMBOL_GPL(trace_event_reg);
317
318 void trace_event_enable_cmd_record(bool enable)
319 {
320 struct trace_event_file *file;
321 struct trace_array *tr;
322
323 mutex_lock(&event_mutex);
324 do_for_each_event_file(tr, file) {
325
326 if (!(file->flags & EVENT_FILE_FL_ENABLED))
327 continue;
328
329 if (enable) {
330 tracing_start_cmdline_record();
331 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
332 } else {
333 tracing_stop_cmdline_record();
334 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
335 }
336 } while_for_each_event_file();
337 mutex_unlock(&event_mutex);
338 }
339
340 void trace_event_enable_tgid_record(bool enable)
341 {
342 struct trace_event_file *file;
343 struct trace_array *tr;
344
345 mutex_lock(&event_mutex);
346 do_for_each_event_file(tr, file) {
347 if (!(file->flags & EVENT_FILE_FL_ENABLED))
348 continue;
349
350 if (enable) {
351 tracing_start_tgid_record();
352 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
353 } else {
354 tracing_stop_tgid_record();
355 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
356 &file->flags);
357 }
358 } while_for_each_event_file();
359 mutex_unlock(&event_mutex);
360 }
361
362 static int __ftrace_event_enable_disable(struct trace_event_file *file,
363 int enable, int soft_disable)
364 {
365 struct trace_event_call *call = file->event_call;
366 struct trace_array *tr = file->tr;
367 unsigned long file_flags = file->flags;
368 int ret = 0;
369 int disable;
370
371 switch (enable) {
372 case 0:
373 /*
374 * When soft_disable is set and enable is cleared, the sm_ref
375 * reference counter is decremented. If it reaches 0, we want
376 * to clear the SOFT_DISABLED flag but leave the event in the
377 * state that it was. That is, if the event was enabled and
378 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
379 * is set we do not want the event to be enabled before we
380 * clear the bit.
381 *
382 * When soft_disable is not set but the SOFT_MODE flag is,
383 * we do nothing. Do not disable the tracepoint, otherwise
384 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
385 */
386 if (soft_disable) {
387 if (atomic_dec_return(&file->sm_ref) > 0)
388 break;
389 disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
390 clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
391 } else
392 disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
393
394 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
395 clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
396 if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
397 tracing_stop_cmdline_record();
398 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
399 }
400
401 if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
402 tracing_stop_tgid_record();
403 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
404 }
405
406 call->class->reg(call, TRACE_REG_UNREGISTER, file);
407 }
408 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
409 if (file->flags & EVENT_FILE_FL_SOFT_MODE)
410 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
411 else
412 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
413 break;
414 case 1:
415 /*
416 * When soft_disable is set and enable is set, we want to
417 * register the tracepoint for the event, but leave the event
418 * as is. That means, if the event was already enabled, we do
419 * nothing (but set SOFT_MODE). If the event is disabled, we
420 * set SOFT_DISABLED before enabling the event tracepoint, so
421 * it still seems to be disabled.
422 */
423 if (!soft_disable)
424 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
425 else {
426 if (atomic_inc_return(&file->sm_ref) > 1)
427 break;
428 set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
429 }
430
431 if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
432 bool cmd = false, tgid = false;
433
434 /* Keep the event disabled, when going to SOFT_MODE. */
435 if (soft_disable)
436 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
437
438 if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
439 cmd = true;
440 tracing_start_cmdline_record();
441 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
442 }
443
444 if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
445 tgid = true;
446 tracing_start_tgid_record();
447 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
448 }
449
450 ret = call->class->reg(call, TRACE_REG_REGISTER, file);
451 if (ret) {
452 if (cmd)
453 tracing_stop_cmdline_record();
454 if (tgid)
455 tracing_stop_tgid_record();
456 pr_info("event trace: Could not enable event "
457 "%s\n", trace_event_name(call));
458 break;
459 }
460 set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
461
462 /* WAS_ENABLED gets set but never cleared. */
463 set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
464 }
465 break;
466 }
467
468 /* Enable or disable use of trace_buffered_event */
469 if ((file_flags & EVENT_FILE_FL_SOFT_DISABLED) !=
470 (file->flags & EVENT_FILE_FL_SOFT_DISABLED)) {
471 if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
472 trace_buffered_event_enable();
473 else
474 trace_buffered_event_disable();
475 }
476
477 return ret;
478 }
479
480 int trace_event_enable_disable(struct trace_event_file *file,
481 int enable, int soft_disable)
482 {
483 return __ftrace_event_enable_disable(file, enable, soft_disable);
484 }
485
486 static int ftrace_event_enable_disable(struct trace_event_file *file,
487 int enable)
488 {
489 return __ftrace_event_enable_disable(file, enable, 0);
490 }
491
492 static void ftrace_clear_events(struct trace_array *tr)
493 {
494 struct trace_event_file *file;
495
496 mutex_lock(&event_mutex);
497 list_for_each_entry(file, &tr->events, list) {
498 ftrace_event_enable_disable(file, 0);
499 }
500 mutex_unlock(&event_mutex);
501 }
502
503 static void
504 event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
505 {
506 struct trace_pid_list *pid_list;
507 struct trace_array *tr = data;
508
509 pid_list = rcu_dereference_raw(tr->filtered_pids);
510 trace_filter_add_remove_task(pid_list, NULL, task);
511 }
512
513 static void
514 event_filter_pid_sched_process_fork(void *data,
515 struct task_struct *self,
516 struct task_struct *task)
517 {
518 struct trace_pid_list *pid_list;
519 struct trace_array *tr = data;
520
521 pid_list = rcu_dereference_sched(tr->filtered_pids);
522 trace_filter_add_remove_task(pid_list, self, task);
523 }
524
525 void trace_event_follow_fork(struct trace_array *tr, bool enable)
526 {
527 if (enable) {
528 register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
529 tr, INT_MIN);
530 register_trace_prio_sched_process_exit(event_filter_pid_sched_process_exit,
531 tr, INT_MAX);
532 } else {
533 unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
534 tr);
535 unregister_trace_sched_process_exit(event_filter_pid_sched_process_exit,
536 tr);
537 }
538 }
539
540 static void
541 event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
542 struct task_struct *prev, struct task_struct *next)
543 {
544 struct trace_array *tr = data;
545 struct trace_pid_list *pid_list;
546
547 pid_list = rcu_dereference_sched(tr->filtered_pids);
548
549 this_cpu_write(tr->trace_buffer.data->ignore_pid,
550 trace_ignore_this_task(pid_list, prev) &&
551 trace_ignore_this_task(pid_list, next));
552 }
553
554 static void
555 event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
556 struct task_struct *prev, struct task_struct *next)
557 {
558 struct trace_array *tr = data;
559 struct trace_pid_list *pid_list;
560
561 pid_list = rcu_dereference_sched(tr->filtered_pids);
562
563 this_cpu_write(tr->trace_buffer.data->ignore_pid,
564 trace_ignore_this_task(pid_list, next));
565 }
566
567 static void
568 event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
569 {
570 struct trace_array *tr = data;
571 struct trace_pid_list *pid_list;
572
573 /* Nothing to do if we are already tracing */
574 if (!this_cpu_read(tr->trace_buffer.data->ignore_pid))
575 return;
576
577 pid_list = rcu_dereference_sched(tr->filtered_pids);
578
579 this_cpu_write(tr->trace_buffer.data->ignore_pid,
580 trace_ignore_this_task(pid_list, task));
581 }
582
583 static void
584 event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
585 {
586 struct trace_array *tr = data;
587 struct trace_pid_list *pid_list;
588
589 /* Nothing to do if we are not tracing */
590 if (this_cpu_read(tr->trace_buffer.data->ignore_pid))
591 return;
592
593 pid_list = rcu_dereference_sched(tr->filtered_pids);
594
595 /* Set tracing if current is enabled */
596 this_cpu_write(tr->trace_buffer.data->ignore_pid,
597 trace_ignore_this_task(pid_list, current));
598 }
599
600 static void __ftrace_clear_event_pids(struct trace_array *tr)
601 {
602 struct trace_pid_list *pid_list;
603 struct trace_event_file *file;
604 int cpu;
605
606 pid_list = rcu_dereference_protected(tr->filtered_pids,
607 lockdep_is_held(&event_mutex));
608 if (!pid_list)
609 return;
610
611 unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
612 unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
613
614 unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
615 unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
616
617 unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
618 unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
619
620 unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
621 unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
622
623 list_for_each_entry(file, &tr->events, list) {
624 clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
625 }
626
627 for_each_possible_cpu(cpu)
628 per_cpu_ptr(tr->trace_buffer.data, cpu)->ignore_pid = false;
629
630 rcu_assign_pointer(tr->filtered_pids, NULL);
631
632 /* Wait till all users are no longer using pid filtering */
633 tracepoint_synchronize_unregister();
634
635 trace_free_pid_list(pid_list);
636 }
637
638 static void ftrace_clear_event_pids(struct trace_array *tr)
639 {
640 mutex_lock(&event_mutex);
641 __ftrace_clear_event_pids(tr);
642 mutex_unlock(&event_mutex);
643 }
644
645 static void __put_system(struct event_subsystem *system)
646 {
647 struct event_filter *filter = system->filter;
648
649 WARN_ON_ONCE(system_refcount(system) == 0);
650 if (system_refcount_dec(system))
651 return;
652
653 list_del(&system->list);
654
655 if (filter) {
656 kfree(filter->filter_string);
657 kfree(filter);
658 }
659 kfree_const(system->name);
660 kfree(system);
661 }
662
663 static void __get_system(struct event_subsystem *system)
664 {
665 WARN_ON_ONCE(system_refcount(system) == 0);
666 system_refcount_inc(system);
667 }
668
669 static void __get_system_dir(struct trace_subsystem_dir *dir)
670 {
671 WARN_ON_ONCE(dir->ref_count == 0);
672 dir->ref_count++;
673 __get_system(dir->subsystem);
674 }
675
676 static void __put_system_dir(struct trace_subsystem_dir *dir)
677 {
678 WARN_ON_ONCE(dir->ref_count == 0);
679 /* If the subsystem is about to be freed, the dir must be too */
680 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
681
682 __put_system(dir->subsystem);
683 if (!--dir->ref_count)
684 kfree(dir);
685 }
686
687 static void put_system(struct trace_subsystem_dir *dir)
688 {
689 mutex_lock(&event_mutex);
690 __put_system_dir(dir);
691 mutex_unlock(&event_mutex);
692 }
693
694 static void remove_subsystem(struct trace_subsystem_dir *dir)
695 {
696 if (!dir)
697 return;
698
699 if (!--dir->nr_events) {
700 tracefs_remove_recursive(dir->entry);
701 list_del(&dir->list);
702 __put_system_dir(dir);
703 }
704 }
705
706 static void remove_event_file_dir(struct trace_event_file *file)
707 {
708 struct dentry *dir = file->dir;
709 struct dentry *child;
710
711 if (dir) {
712 spin_lock(&dir->d_lock); /* probably unneeded */
713 list_for_each_entry(child, &dir->d_subdirs, d_child) {
714 if (d_really_is_positive(child)) /* probably unneeded */
715 d_inode(child)->i_private = NULL;
716 }
717 spin_unlock(&dir->d_lock);
718
719 tracefs_remove_recursive(dir);
720 }
721
722 list_del(&file->list);
723 remove_subsystem(file->system);
724 free_event_filter(file->filter);
725 kmem_cache_free(file_cachep, file);
726 }
727
728 /*
729 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
730 */
731 static int
732 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
733 const char *sub, const char *event, int set)
734 {
735 struct trace_event_file *file;
736 struct trace_event_call *call;
737 const char *name;
738 int ret = -EINVAL;
739 int eret = 0;
740
741 list_for_each_entry(file, &tr->events, list) {
742
743 call = file->event_call;
744 name = trace_event_name(call);
745
746 if (!name || !call->class || !call->class->reg)
747 continue;
748
749 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
750 continue;
751
752 if (match &&
753 strcmp(match, name) != 0 &&
754 strcmp(match, call->class->system) != 0)
755 continue;
756
757 if (sub && strcmp(sub, call->class->system) != 0)
758 continue;
759
760 if (event && strcmp(event, name) != 0)
761 continue;
762
763 ret = ftrace_event_enable_disable(file, set);
764
765 /*
766 * Save the first error and return that. Some events
767 * may still have been enabled, but let the user
768 * know that something went wrong.
769 */
770 if (ret && !eret)
771 eret = ret;
772
773 ret = eret;
774 }
775
776 return ret;
777 }
778
779 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
780 const char *sub, const char *event, int set)
781 {
782 int ret;
783
784 mutex_lock(&event_mutex);
785 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
786 mutex_unlock(&event_mutex);
787
788 return ret;
789 }
790
791 int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
792 {
793 char *event = NULL, *sub = NULL, *match;
794 int ret;
795
796 if (!tr)
797 return -ENOENT;
798 /*
799 * The buf format can be <subsystem>:<event-name>
800 * *:<event-name> means any event by that name.
801 * :<event-name> is the same.
802 *
803 * <subsystem>:* means all events in that subsystem
804 * <subsystem>: means the same.
805 *
806 * <name> (no ':') means all events in a subsystem with
807 * the name <name> or any event that matches <name>
808 */
809
810 match = strsep(&buf, ":");
811 if (buf) {
812 sub = match;
813 event = buf;
814 match = NULL;
815
816 if (!strlen(sub) || strcmp(sub, "*") == 0)
817 sub = NULL;
818 if (!strlen(event) || strcmp(event, "*") == 0)
819 event = NULL;
820 }
821
822 ret = __ftrace_set_clr_event(tr, match, sub, event, set);
823
824 /* Put back the colon to allow this to be called again */
825 if (buf)
826 *(buf - 1) = ':';
827
828 return ret;
829 }
830
831 /**
832 * trace_set_clr_event - enable or disable an event
833 * @system: system name to match (NULL for any system)
834 * @event: event name to match (NULL for all events, within system)
835 * @set: 1 to enable, 0 to disable
836 *
837 * This is a way for other parts of the kernel to enable or disable
838 * event recording.
839 *
840 * Returns 0 on success, -EINVAL if the parameters do not match any
841 * registered events.
842 */
843 int trace_set_clr_event(const char *system, const char *event, int set)
844 {
845 struct trace_array *tr = top_trace_array();
846
847 if (!tr)
848 return -ENODEV;
849
850 return __ftrace_set_clr_event(tr, NULL, system, event, set);
851 }
852 EXPORT_SYMBOL_GPL(trace_set_clr_event);
853
854 /**
855 * trace_array_set_clr_event - enable or disable an event for a trace array.
856 * @tr: concerned trace array.
857 * @system: system name to match (NULL for any system)
858 * @event: event name to match (NULL for all events, within system)
859 * @enable: true to enable, false to disable
860 *
861 * This is a way for other parts of the kernel to enable or disable
862 * event recording.
863 *
864 * Returns 0 on success, -EINVAL if the parameters do not match any
865 * registered events.
866 */
867 int trace_array_set_clr_event(struct trace_array *tr, const char *system,
868 const char *event, bool enable)
869 {
870 int set;
871
872 if (!tr)
873 return -ENOENT;
874
875 set = (enable == true) ? 1 : 0;
876 return __ftrace_set_clr_event(tr, NULL, system, event, set);
877 }
878 EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
879
880 /* 128 should be much more than enough */
881 #define EVENT_BUF_SIZE 127
882
883 static ssize_t
884 ftrace_event_write(struct file *file, const char __user *ubuf,
885 size_t cnt, loff_t *ppos)
886 {
887 struct trace_parser parser;
888 struct seq_file *m = file->private_data;
889 struct trace_array *tr = m->private;
890 ssize_t read, ret;
891
892 if (!cnt)
893 return 0;
894
895 ret = tracing_update_buffers();
896 if (ret < 0)
897 return ret;
898
899 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
900 return -ENOMEM;
901
902 read = trace_get_user(&parser, ubuf, cnt, ppos);
903
904 if (read >= 0 && trace_parser_loaded((&parser))) {
905 int set = 1;
906
907 if (*parser.buffer == '!')
908 set = 0;
909
910 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
911 if (ret)
912 goto out_put;
913 }
914
915 ret = read;
916
917 out_put:
918 trace_parser_put(&parser);
919
920 return ret;
921 }
922
923 static void *
924 t_next(struct seq_file *m, void *v, loff_t *pos)
925 {
926 struct trace_event_file *file = v;
927 struct trace_event_call *call;
928 struct trace_array *tr = m->private;
929
930 (*pos)++;
931
932 list_for_each_entry_continue(file, &tr->events, list) {
933 call = file->event_call;
934 /*
935 * The ftrace subsystem is for showing formats only.
936 * They can not be enabled or disabled via the event files.
937 */
938 if (call->class && call->class->reg &&
939 !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
940 return file;
941 }
942
943 return NULL;
944 }
945
946 static void *t_start(struct seq_file *m, loff_t *pos)
947 {
948 struct trace_event_file *file;
949 struct trace_array *tr = m->private;
950 loff_t l;
951
952 mutex_lock(&event_mutex);
953
954 file = list_entry(&tr->events, struct trace_event_file, list);
955 for (l = 0; l <= *pos; ) {
956 file = t_next(m, file, &l);
957 if (!file)
958 break;
959 }
960 return file;
961 }
962
963 static void *
964 s_next(struct seq_file *m, void *v, loff_t *pos)
965 {
966 struct trace_event_file *file = v;
967 struct trace_array *tr = m->private;
968
969 (*pos)++;
970
971 list_for_each_entry_continue(file, &tr->events, list) {
972 if (file->flags & EVENT_FILE_FL_ENABLED)
973 return file;
974 }
975
976 return NULL;
977 }
978
979 static void *s_start(struct seq_file *m, loff_t *pos)
980 {
981 struct trace_event_file *file;
982 struct trace_array *tr = m->private;
983 loff_t l;
984
985 mutex_lock(&event_mutex);
986
987 file = list_entry(&tr->events, struct trace_event_file, list);
988 for (l = 0; l <= *pos; ) {
989 file = s_next(m, file, &l);
990 if (!file)
991 break;
992 }
993 return file;
994 }
995
996 static int t_show(struct seq_file *m, void *v)
997 {
998 struct trace_event_file *file = v;
999 struct trace_event_call *call = file->event_call;
1000
1001 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1002 seq_printf(m, "%s:", call->class->system);
1003 seq_printf(m, "%s\n", trace_event_name(call));
1004
1005 return 0;
1006 }
1007
1008 static void t_stop(struct seq_file *m, void *p)
1009 {
1010 mutex_unlock(&event_mutex);
1011 }
1012
1013 static void *
1014 p_next(struct seq_file *m, void *v, loff_t *pos)
1015 {
1016 struct trace_array *tr = m->private;
1017 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids);
1018
1019 return trace_pid_next(pid_list, v, pos);
1020 }
1021
1022 static void *p_start(struct seq_file *m, loff_t *pos)
1023 __acquires(RCU)
1024 {
1025 struct trace_pid_list *pid_list;
1026 struct trace_array *tr = m->private;
1027
1028 /*
1029 * Grab the mutex, to keep calls to p_next() having the same
1030 * tr->filtered_pids as p_start() has.
1031 * If we just passed the tr->filtered_pids around, then RCU would
1032 * have been enough, but doing that makes things more complex.
1033 */
1034 mutex_lock(&event_mutex);
1035 rcu_read_lock_sched();
1036
1037 pid_list = rcu_dereference_sched(tr->filtered_pids);
1038
1039 if (!pid_list)
1040 return NULL;
1041
1042 return trace_pid_start(pid_list, pos);
1043 }
1044
1045 static void p_stop(struct seq_file *m, void *p)
1046 __releases(RCU)
1047 {
1048 rcu_read_unlock_sched();
1049 mutex_unlock(&event_mutex);
1050 }
1051
1052 static ssize_t
1053 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1054 loff_t *ppos)
1055 {
1056 struct trace_event_file *file;
1057 unsigned long flags;
1058 char buf[4] = "0";
1059
1060 mutex_lock(&event_mutex);
1061 file = event_file_data(filp);
1062 if (likely(file))
1063 flags = file->flags;
1064 mutex_unlock(&event_mutex);
1065
1066 if (!file)
1067 return -ENODEV;
1068
1069 if (flags & EVENT_FILE_FL_ENABLED &&
1070 !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1071 strcpy(buf, "1");
1072
1073 if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1074 flags & EVENT_FILE_FL_SOFT_MODE)
1075 strcat(buf, "*");
1076
1077 strcat(buf, "\n");
1078
1079 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1080 }
1081
1082 static ssize_t
1083 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1084 loff_t *ppos)
1085 {
1086 struct trace_event_file *file;
1087 unsigned long val;
1088 int ret;
1089
1090 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1091 if (ret)
1092 return ret;
1093
1094 ret = tracing_update_buffers();
1095 if (ret < 0)
1096 return ret;
1097
1098 switch (val) {
1099 case 0:
1100 case 1:
1101 ret = -ENODEV;
1102 mutex_lock(&event_mutex);
1103 file = event_file_data(filp);
1104 if (likely(file))
1105 ret = ftrace_event_enable_disable(file, val);
1106 mutex_unlock(&event_mutex);
1107 break;
1108
1109 default:
1110 return -EINVAL;
1111 }
1112
1113 *ppos += cnt;
1114
1115 return ret ? ret : cnt;
1116 }
1117
1118 static ssize_t
1119 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1120 loff_t *ppos)
1121 {
1122 const char set_to_char[4] = { '?', '0', '1', 'X' };
1123 struct trace_subsystem_dir *dir = filp->private_data;
1124 struct event_subsystem *system = dir->subsystem;
1125 struct trace_event_call *call;
1126 struct trace_event_file *file;
1127 struct trace_array *tr = dir->tr;
1128 char buf[2];
1129 int set = 0;
1130 int ret;
1131
1132 mutex_lock(&event_mutex);
1133 list_for_each_entry(file, &tr->events, list) {
1134 call = file->event_call;
1135 if (!trace_event_name(call) || !call->class || !call->class->reg)
1136 continue;
1137
1138 if (system && strcmp(call->class->system, system->name) != 0)
1139 continue;
1140
1141 /*
1142 * We need to find out if all the events are set
1143 * or if all events or cleared, or if we have
1144 * a mixture.
1145 */
1146 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1147
1148 /*
1149 * If we have a mixture, no need to look further.
1150 */
1151 if (set == 3)
1152 break;
1153 }
1154 mutex_unlock(&event_mutex);
1155
1156 buf[0] = set_to_char[set];
1157 buf[1] = '\n';
1158
1159 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1160
1161 return ret;
1162 }
1163
1164 static ssize_t
1165 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1166 loff_t *ppos)
1167 {
1168 struct trace_subsystem_dir *dir = filp->private_data;
1169 struct event_subsystem *system = dir->subsystem;
1170 const char *name = NULL;
1171 unsigned long val;
1172 ssize_t ret;
1173
1174 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1175 if (ret)
1176 return ret;
1177
1178 ret = tracing_update_buffers();
1179 if (ret < 0)
1180 return ret;
1181
1182 if (val != 0 && val != 1)
1183 return -EINVAL;
1184
1185 /*
1186 * Opening of "enable" adds a ref count to system,
1187 * so the name is safe to use.
1188 */
1189 if (system)
1190 name = system->name;
1191
1192 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1193 if (ret)
1194 goto out;
1195
1196 ret = cnt;
1197
1198 out:
1199 *ppos += cnt;
1200
1201 return ret;
1202 }
1203
1204 enum {
1205 FORMAT_HEADER = 1,
1206 FORMAT_FIELD_SEPERATOR = 2,
1207 FORMAT_PRINTFMT = 3,
1208 };
1209
1210 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1211 {
1212 struct trace_event_call *call = event_file_data(m->private);
1213 struct list_head *common_head = &ftrace_common_fields;
1214 struct list_head *head = trace_get_fields(call);
1215 struct list_head *node = v;
1216
1217 (*pos)++;
1218
1219 switch ((unsigned long)v) {
1220 case FORMAT_HEADER:
1221 node = common_head;
1222 break;
1223
1224 case FORMAT_FIELD_SEPERATOR:
1225 node = head;
1226 break;
1227
1228 case FORMAT_PRINTFMT:
1229 /* all done */
1230 return NULL;
1231 }
1232
1233 node = node->prev;
1234 if (node == common_head)
1235 return (void *)FORMAT_FIELD_SEPERATOR;
1236 else if (node == head)
1237 return (void *)FORMAT_PRINTFMT;
1238 else
1239 return node;
1240 }
1241
1242 static int f_show(struct seq_file *m, void *v)
1243 {
1244 struct trace_event_call *call = event_file_data(m->private);
1245 struct ftrace_event_field *field;
1246 const char *array_descriptor;
1247
1248 switch ((unsigned long)v) {
1249 case FORMAT_HEADER:
1250 seq_printf(m, "name: %s\n", trace_event_name(call));
1251 seq_printf(m, "ID: %d\n", call->event.type);
1252 seq_puts(m, "format:\n");
1253 return 0;
1254
1255 case FORMAT_FIELD_SEPERATOR:
1256 seq_putc(m, '\n');
1257 return 0;
1258
1259 case FORMAT_PRINTFMT:
1260 seq_printf(m, "\nprint fmt: %s\n",
1261 call->print_fmt);
1262 return 0;
1263 }
1264
1265 field = list_entry(v, struct ftrace_event_field, link);
1266 /*
1267 * Smartly shows the array type(except dynamic array).
1268 * Normal:
1269 * field:TYPE VAR
1270 * If TYPE := TYPE[LEN], it is shown:
1271 * field:TYPE VAR[LEN]
1272 */
1273 array_descriptor = strchr(field->type, '[');
1274
1275 if (str_has_prefix(field->type, "__data_loc"))
1276 array_descriptor = NULL;
1277
1278 if (!array_descriptor)
1279 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1280 field->type, field->name, field->offset,
1281 field->size, !!field->is_signed);
1282 else
1283 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1284 (int)(array_descriptor - field->type),
1285 field->type, field->name,
1286 array_descriptor, field->offset,
1287 field->size, !!field->is_signed);
1288
1289 return 0;
1290 }
1291
1292 static void *f_start(struct seq_file *m, loff_t *pos)
1293 {
1294 void *p = (void *)FORMAT_HEADER;
1295 loff_t l = 0;
1296
1297 /* ->stop() is called even if ->start() fails */
1298 mutex_lock(&event_mutex);
1299 if (!event_file_data(m->private))
1300 return ERR_PTR(-ENODEV);
1301
1302 while (l < *pos && p)
1303 p = f_next(m, p, &l);
1304
1305 return p;
1306 }
1307
1308 static void f_stop(struct seq_file *m, void *p)
1309 {
1310 mutex_unlock(&event_mutex);
1311 }
1312
1313 static const struct seq_operations trace_format_seq_ops = {
1314 .start = f_start,
1315 .next = f_next,
1316 .stop = f_stop,
1317 .show = f_show,
1318 };
1319
1320 static int trace_format_open(struct inode *inode, struct file *file)
1321 {
1322 struct seq_file *m;
1323 int ret;
1324
1325 /* Do we want to hide event format files on tracefs lockdown? */
1326
1327 ret = seq_open(file, &trace_format_seq_ops);
1328 if (ret < 0)
1329 return ret;
1330
1331 m = file->private_data;
1332 m->private = file;
1333
1334 return 0;
1335 }
1336
1337 static ssize_t
1338 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1339 {
1340 int id = (long)event_file_data(filp);
1341 char buf[32];
1342 int len;
1343
1344 if (unlikely(!id))
1345 return -ENODEV;
1346
1347 len = sprintf(buf, "%d\n", id);
1348
1349 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1350 }
1351
1352 static ssize_t
1353 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1354 loff_t *ppos)
1355 {
1356 struct trace_event_file *file;
1357 struct trace_seq *s;
1358 int r = -ENODEV;
1359
1360 if (*ppos)
1361 return 0;
1362
1363 s = kmalloc(sizeof(*s), GFP_KERNEL);
1364
1365 if (!s)
1366 return -ENOMEM;
1367
1368 trace_seq_init(s);
1369
1370 mutex_lock(&event_mutex);
1371 file = event_file_data(filp);
1372 if (file)
1373 print_event_filter(file, s);
1374 mutex_unlock(&event_mutex);
1375
1376 if (file)
1377 r = simple_read_from_buffer(ubuf, cnt, ppos,
1378 s->buffer, trace_seq_used(s));
1379
1380 kfree(s);
1381
1382 return r;
1383 }
1384
1385 static ssize_t
1386 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1387 loff_t *ppos)
1388 {
1389 struct trace_event_file *file;
1390 char *buf;
1391 int err = -ENODEV;
1392
1393 if (cnt >= PAGE_SIZE)
1394 return -EINVAL;
1395
1396 buf = memdup_user_nul(ubuf, cnt);
1397 if (IS_ERR(buf))
1398 return PTR_ERR(buf);
1399
1400 mutex_lock(&event_mutex);
1401 file = event_file_data(filp);
1402 if (file)
1403 err = apply_event_filter(file, buf);
1404 mutex_unlock(&event_mutex);
1405
1406 kfree(buf);
1407 if (err < 0)
1408 return err;
1409
1410 *ppos += cnt;
1411
1412 return cnt;
1413 }
1414
1415 static LIST_HEAD(event_subsystems);
1416
1417 static int subsystem_open(struct inode *inode, struct file *filp)
1418 {
1419 struct event_subsystem *system = NULL;
1420 struct trace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1421 struct trace_array *tr;
1422 int ret;
1423
1424 if (tracing_is_disabled())
1425 return -ENODEV;
1426
1427 /* Make sure the system still exists */
1428 mutex_lock(&event_mutex);
1429 mutex_lock(&trace_types_lock);
1430 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1431 list_for_each_entry(dir, &tr->systems, list) {
1432 if (dir == inode->i_private) {
1433 /* Don't open systems with no events */
1434 if (dir->nr_events) {
1435 __get_system_dir(dir);
1436 system = dir->subsystem;
1437 }
1438 goto exit_loop;
1439 }
1440 }
1441 }
1442 exit_loop:
1443 mutex_unlock(&trace_types_lock);
1444 mutex_unlock(&event_mutex);
1445
1446 if (!system)
1447 return -ENODEV;
1448
1449 /* Some versions of gcc think dir can be uninitialized here */
1450 WARN_ON(!dir);
1451
1452 /* Still need to increment the ref count of the system */
1453 if (trace_array_get(tr) < 0) {
1454 put_system(dir);
1455 return -ENODEV;
1456 }
1457
1458 ret = tracing_open_generic(inode, filp);
1459 if (ret < 0) {
1460 trace_array_put(tr);
1461 put_system(dir);
1462 }
1463
1464 return ret;
1465 }
1466
1467 static int system_tr_open(struct inode *inode, struct file *filp)
1468 {
1469 struct trace_subsystem_dir *dir;
1470 struct trace_array *tr = inode->i_private;
1471 int ret;
1472
1473 /* Make a temporary dir that has no system but points to tr */
1474 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1475 if (!dir)
1476 return -ENOMEM;
1477
1478 ret = tracing_open_generic_tr(inode, filp);
1479 if (ret < 0) {
1480 kfree(dir);
1481 return ret;
1482 }
1483 dir->tr = tr;
1484 filp->private_data = dir;
1485
1486 return 0;
1487 }
1488
1489 static int subsystem_release(struct inode *inode, struct file *file)
1490 {
1491 struct trace_subsystem_dir *dir = file->private_data;
1492
1493 trace_array_put(dir->tr);
1494
1495 /*
1496 * If dir->subsystem is NULL, then this is a temporary
1497 * descriptor that was made for a trace_array to enable
1498 * all subsystems.
1499 */
1500 if (dir->subsystem)
1501 put_system(dir);
1502 else
1503 kfree(dir);
1504
1505 return 0;
1506 }
1507
1508 static ssize_t
1509 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1510 loff_t *ppos)
1511 {
1512 struct trace_subsystem_dir *dir = filp->private_data;
1513 struct event_subsystem *system = dir->subsystem;
1514 struct trace_seq *s;
1515 int r;
1516
1517 if (*ppos)
1518 return 0;
1519
1520 s = kmalloc(sizeof(*s), GFP_KERNEL);
1521 if (!s)
1522 return -ENOMEM;
1523
1524 trace_seq_init(s);
1525
1526 print_subsystem_event_filter(system, s);
1527 r = simple_read_from_buffer(ubuf, cnt, ppos,
1528 s->buffer, trace_seq_used(s));
1529
1530 kfree(s);
1531
1532 return r;
1533 }
1534
1535 static ssize_t
1536 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1537 loff_t *ppos)
1538 {
1539 struct trace_subsystem_dir *dir = filp->private_data;
1540 char *buf;
1541 int err;
1542
1543 if (cnt >= PAGE_SIZE)
1544 return -EINVAL;
1545
1546 buf = memdup_user_nul(ubuf, cnt);
1547 if (IS_ERR(buf))
1548 return PTR_ERR(buf);
1549
1550 err = apply_subsystem_event_filter(dir, buf);
1551 kfree(buf);
1552 if (err < 0)
1553 return err;
1554
1555 *ppos += cnt;
1556
1557 return cnt;
1558 }
1559
1560 static ssize_t
1561 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1562 {
1563 int (*func)(struct trace_seq *s) = filp->private_data;
1564 struct trace_seq *s;
1565 int r;
1566
1567 if (*ppos)
1568 return 0;
1569
1570 s = kmalloc(sizeof(*s), GFP_KERNEL);
1571 if (!s)
1572 return -ENOMEM;
1573
1574 trace_seq_init(s);
1575
1576 func(s);
1577 r = simple_read_from_buffer(ubuf, cnt, ppos,
1578 s->buffer, trace_seq_used(s));
1579
1580 kfree(s);
1581
1582 return r;
1583 }
1584
1585 static void ignore_task_cpu(void *data)
1586 {
1587 struct trace_array *tr = data;
1588 struct trace_pid_list *pid_list;
1589
1590 /*
1591 * This function is called by on_each_cpu() while the
1592 * event_mutex is held.
1593 */
1594 pid_list = rcu_dereference_protected(tr->filtered_pids,
1595 mutex_is_locked(&event_mutex));
1596
1597 this_cpu_write(tr->trace_buffer.data->ignore_pid,
1598 trace_ignore_this_task(pid_list, current));
1599 }
1600
1601 static ssize_t
1602 ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
1603 size_t cnt, loff_t *ppos)
1604 {
1605 struct seq_file *m = filp->private_data;
1606 struct trace_array *tr = m->private;
1607 struct trace_pid_list *filtered_pids = NULL;
1608 struct trace_pid_list *pid_list;
1609 struct trace_event_file *file;
1610 ssize_t ret;
1611
1612 if (!cnt)
1613 return 0;
1614
1615 ret = tracing_update_buffers();
1616 if (ret < 0)
1617 return ret;
1618
1619 mutex_lock(&event_mutex);
1620
1621 filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1622 lockdep_is_held(&event_mutex));
1623
1624 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
1625 if (ret < 0)
1626 goto out;
1627
1628 rcu_assign_pointer(tr->filtered_pids, pid_list);
1629
1630 list_for_each_entry(file, &tr->events, list) {
1631 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
1632 }
1633
1634 if (filtered_pids) {
1635 tracepoint_synchronize_unregister();
1636 trace_free_pid_list(filtered_pids);
1637 } else if (pid_list) {
1638 /*
1639 * Register a probe that is called before all other probes
1640 * to set ignore_pid if next or prev do not match.
1641 * Register a probe this is called after all other probes
1642 * to only keep ignore_pid set if next pid matches.
1643 */
1644 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1645 tr, INT_MAX);
1646 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1647 tr, 0);
1648
1649 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1650 tr, INT_MAX);
1651 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1652 tr, 0);
1653
1654 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1655 tr, INT_MAX);
1656 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1657 tr, 0);
1658
1659 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1660 tr, INT_MAX);
1661 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1662 tr, 0);
1663 }
1664
1665 /*
1666 * Ignoring of pids is done at task switch. But we have to
1667 * check for those tasks that are currently running.
1668 * Always do this in case a pid was appended or removed.
1669 */
1670 on_each_cpu(ignore_task_cpu, tr, 1);
1671
1672 out:
1673 mutex_unlock(&event_mutex);
1674
1675 if (ret > 0)
1676 *ppos += ret;
1677
1678 return ret;
1679 }
1680
1681 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1682 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1683 static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
1684 static int ftrace_event_release(struct inode *inode, struct file *file);
1685
1686 static const struct seq_operations show_event_seq_ops = {
1687 .start = t_start,
1688 .next = t_next,
1689 .show = t_show,
1690 .stop = t_stop,
1691 };
1692
1693 static const struct seq_operations show_set_event_seq_ops = {
1694 .start = s_start,
1695 .next = s_next,
1696 .show = t_show,
1697 .stop = t_stop,
1698 };
1699
1700 static const struct seq_operations show_set_pid_seq_ops = {
1701 .start = p_start,
1702 .next = p_next,
1703 .show = trace_pid_show,
1704 .stop = p_stop,
1705 };
1706
1707 static const struct file_operations ftrace_avail_fops = {
1708 .open = ftrace_event_avail_open,
1709 .read = seq_read,
1710 .llseek = seq_lseek,
1711 .release = seq_release,
1712 };
1713
1714 static const struct file_operations ftrace_set_event_fops = {
1715 .open = ftrace_event_set_open,
1716 .read = seq_read,
1717 .write = ftrace_event_write,
1718 .llseek = seq_lseek,
1719 .release = ftrace_event_release,
1720 };
1721
1722 static const struct file_operations ftrace_set_event_pid_fops = {
1723 .open = ftrace_event_set_pid_open,
1724 .read = seq_read,
1725 .write = ftrace_event_pid_write,
1726 .llseek = seq_lseek,
1727 .release = ftrace_event_release,
1728 };
1729
1730 static const struct file_operations ftrace_enable_fops = {
1731 .open = tracing_open_generic,
1732 .read = event_enable_read,
1733 .write = event_enable_write,
1734 .llseek = default_llseek,
1735 };
1736
1737 static const struct file_operations ftrace_event_format_fops = {
1738 .open = trace_format_open,
1739 .read = seq_read,
1740 .llseek = seq_lseek,
1741 .release = seq_release,
1742 };
1743
1744 static const struct file_operations ftrace_event_id_fops = {
1745 .read = event_id_read,
1746 .llseek = default_llseek,
1747 };
1748
1749 static const struct file_operations ftrace_event_filter_fops = {
1750 .open = tracing_open_generic,
1751 .read = event_filter_read,
1752 .write = event_filter_write,
1753 .llseek = default_llseek,
1754 };
1755
1756 static const struct file_operations ftrace_subsystem_filter_fops = {
1757 .open = subsystem_open,
1758 .read = subsystem_filter_read,
1759 .write = subsystem_filter_write,
1760 .llseek = default_llseek,
1761 .release = subsystem_release,
1762 };
1763
1764 static const struct file_operations ftrace_system_enable_fops = {
1765 .open = subsystem_open,
1766 .read = system_enable_read,
1767 .write = system_enable_write,
1768 .llseek = default_llseek,
1769 .release = subsystem_release,
1770 };
1771
1772 static const struct file_operations ftrace_tr_enable_fops = {
1773 .open = system_tr_open,
1774 .read = system_enable_read,
1775 .write = system_enable_write,
1776 .llseek = default_llseek,
1777 .release = subsystem_release,
1778 };
1779
1780 static const struct file_operations ftrace_show_header_fops = {
1781 .open = tracing_open_generic,
1782 .read = show_header,
1783 .llseek = default_llseek,
1784 };
1785
1786 static int
1787 ftrace_event_open(struct inode *inode, struct file *file,
1788 const struct seq_operations *seq_ops)
1789 {
1790 struct seq_file *m;
1791 int ret;
1792
1793 ret = security_locked_down(LOCKDOWN_TRACEFS);
1794 if (ret)
1795 return ret;
1796
1797 ret = seq_open(file, seq_ops);
1798 if (ret < 0)
1799 return ret;
1800 m = file->private_data;
1801 /* copy tr over to seq ops */
1802 m->private = inode->i_private;
1803
1804 return ret;
1805 }
1806
1807 static int ftrace_event_release(struct inode *inode, struct file *file)
1808 {
1809 struct trace_array *tr = inode->i_private;
1810
1811 trace_array_put(tr);
1812
1813 return seq_release(inode, file);
1814 }
1815
1816 static int
1817 ftrace_event_avail_open(struct inode *inode, struct file *file)
1818 {
1819 const struct seq_operations *seq_ops = &show_event_seq_ops;
1820
1821 /* Checks for tracefs lockdown */
1822 return ftrace_event_open(inode, file, seq_ops);
1823 }
1824
1825 static int
1826 ftrace_event_set_open(struct inode *inode, struct file *file)
1827 {
1828 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1829 struct trace_array *tr = inode->i_private;
1830 int ret;
1831
1832 ret = tracing_check_open_get_tr(tr);
1833 if (ret)
1834 return ret;
1835
1836 if ((file->f_mode & FMODE_WRITE) &&
1837 (file->f_flags & O_TRUNC))
1838 ftrace_clear_events(tr);
1839
1840 ret = ftrace_event_open(inode, file, seq_ops);
1841 if (ret < 0)
1842 trace_array_put(tr);
1843 return ret;
1844 }
1845
1846 static int
1847 ftrace_event_set_pid_open(struct inode *inode, struct file *file)
1848 {
1849 const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
1850 struct trace_array *tr = inode->i_private;
1851 int ret;
1852
1853 ret = tracing_check_open_get_tr(tr);
1854 if (ret)
1855 return ret;
1856
1857 if ((file->f_mode & FMODE_WRITE) &&
1858 (file->f_flags & O_TRUNC))
1859 ftrace_clear_event_pids(tr);
1860
1861 ret = ftrace_event_open(inode, file, seq_ops);
1862 if (ret < 0)
1863 trace_array_put(tr);
1864 return ret;
1865 }
1866
1867 static struct event_subsystem *
1868 create_new_subsystem(const char *name)
1869 {
1870 struct event_subsystem *system;
1871
1872 /* need to create new entry */
1873 system = kmalloc(sizeof(*system), GFP_KERNEL);
1874 if (!system)
1875 return NULL;
1876
1877 system->ref_count = 1;
1878
1879 /* Only allocate if dynamic (kprobes and modules) */
1880 system->name = kstrdup_const(name, GFP_KERNEL);
1881 if (!system->name)
1882 goto out_free;
1883
1884 system->filter = NULL;
1885
1886 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1887 if (!system->filter)
1888 goto out_free;
1889
1890 list_add(&system->list, &event_subsystems);
1891
1892 return system;
1893
1894 out_free:
1895 kfree_const(system->name);
1896 kfree(system);
1897 return NULL;
1898 }
1899
1900 static struct dentry *
1901 event_subsystem_dir(struct trace_array *tr, const char *name,
1902 struct trace_event_file *file, struct dentry *parent)
1903 {
1904 struct trace_subsystem_dir *dir;
1905 struct event_subsystem *system;
1906 struct dentry *entry;
1907
1908 /* First see if we did not already create this dir */
1909 list_for_each_entry(dir, &tr->systems, list) {
1910 system = dir->subsystem;
1911 if (strcmp(system->name, name) == 0) {
1912 dir->nr_events++;
1913 file->system = dir;
1914 return dir->entry;
1915 }
1916 }
1917
1918 /* Now see if the system itself exists. */
1919 list_for_each_entry(system, &event_subsystems, list) {
1920 if (strcmp(system->name, name) == 0)
1921 break;
1922 }
1923 /* Reset system variable when not found */
1924 if (&system->list == &event_subsystems)
1925 system = NULL;
1926
1927 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1928 if (!dir)
1929 goto out_fail;
1930
1931 if (!system) {
1932 system = create_new_subsystem(name);
1933 if (!system)
1934 goto out_free;
1935 } else
1936 __get_system(system);
1937
1938 dir->entry = tracefs_create_dir(name, parent);
1939 if (!dir->entry) {
1940 pr_warn("Failed to create system directory %s\n", name);
1941 __put_system(system);
1942 goto out_free;
1943 }
1944
1945 dir->tr = tr;
1946 dir->ref_count = 1;
1947 dir->nr_events = 1;
1948 dir->subsystem = system;
1949 file->system = dir;
1950
1951 entry = tracefs_create_file("filter", 0644, dir->entry, dir,
1952 &ftrace_subsystem_filter_fops);
1953 if (!entry) {
1954 kfree(system->filter);
1955 system->filter = NULL;
1956 pr_warn("Could not create tracefs '%s/filter' entry\n", name);
1957 }
1958
1959 trace_create_file("enable", 0644, dir->entry, dir,
1960 &ftrace_system_enable_fops);
1961
1962 list_add(&dir->list, &tr->systems);
1963
1964 return dir->entry;
1965
1966 out_free:
1967 kfree(dir);
1968 out_fail:
1969 /* Only print this message if failed on memory allocation */
1970 if (!dir || !system)
1971 pr_warn("No memory to create event subsystem %s\n", name);
1972 return NULL;
1973 }
1974
1975 static int
1976 event_create_dir(struct dentry *parent, struct trace_event_file *file)
1977 {
1978 struct trace_event_call *call = file->event_call;
1979 struct trace_array *tr = file->tr;
1980 struct list_head *head;
1981 struct dentry *d_events;
1982 const char *name;
1983 int ret;
1984
1985 /*
1986 * If the trace point header did not define TRACE_SYSTEM
1987 * then the system would be called "TRACE_SYSTEM".
1988 */
1989 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1990 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1991 if (!d_events)
1992 return -ENOMEM;
1993 } else
1994 d_events = parent;
1995
1996 name = trace_event_name(call);
1997 file->dir = tracefs_create_dir(name, d_events);
1998 if (!file->dir) {
1999 pr_warn("Could not create tracefs '%s' directory\n", name);
2000 return -1;
2001 }
2002
2003 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
2004 trace_create_file("enable", 0644, file->dir, file,
2005 &ftrace_enable_fops);
2006
2007 #ifdef CONFIG_PERF_EVENTS
2008 if (call->event.type && call->class->reg)
2009 trace_create_file("id", 0444, file->dir,
2010 (void *)(long)call->event.type,
2011 &ftrace_event_id_fops);
2012 #endif
2013
2014 /*
2015 * Other events may have the same class. Only update
2016 * the fields if they are not already defined.
2017 */
2018 head = trace_get_fields(call);
2019 if (list_empty(head)) {
2020 ret = call->class->define_fields(call);
2021 if (ret < 0) {
2022 pr_warn("Could not initialize trace point events/%s\n",
2023 name);
2024 return -1;
2025 }
2026 }
2027
2028 /*
2029 * Only event directories that can be enabled should have
2030 * triggers or filters.
2031 */
2032 if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
2033 trace_create_file("filter", 0644, file->dir, file,
2034 &ftrace_event_filter_fops);
2035
2036 trace_create_file("trigger", 0644, file->dir, file,
2037 &event_trigger_fops);
2038 }
2039
2040 #ifdef CONFIG_HIST_TRIGGERS
2041 trace_create_file("hist", 0444, file->dir, file,
2042 &event_hist_fops);
2043 #endif
2044 trace_create_file("format", 0444, file->dir, call,
2045 &ftrace_event_format_fops);
2046
2047 #ifdef CONFIG_TRACE_EVENT_INJECT
2048 if (call->event.type && call->class->reg)
2049 trace_create_file("inject", 0200, file->dir, file,
2050 &event_inject_fops);
2051 #endif
2052
2053 return 0;
2054 }
2055
2056 static void remove_event_from_tracers(struct trace_event_call *call)
2057 {
2058 struct trace_event_file *file;
2059 struct trace_array *tr;
2060
2061 do_for_each_event_file_safe(tr, file) {
2062 if (file->event_call != call)
2063 continue;
2064
2065 remove_event_file_dir(file);
2066 /*
2067 * The do_for_each_event_file_safe() is
2068 * a double loop. After finding the call for this
2069 * trace_array, we use break to jump to the next
2070 * trace_array.
2071 */
2072 break;
2073 } while_for_each_event_file();
2074 }
2075
2076 static void event_remove(struct trace_event_call *call)
2077 {
2078 struct trace_array *tr;
2079 struct trace_event_file *file;
2080
2081 do_for_each_event_file(tr, file) {
2082 if (file->event_call != call)
2083 continue;
2084
2085 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2086 tr->clear_trace = true;
2087
2088 ftrace_event_enable_disable(file, 0);
2089 /*
2090 * The do_for_each_event_file() is
2091 * a double loop. After finding the call for this
2092 * trace_array, we use break to jump to the next
2093 * trace_array.
2094 */
2095 break;
2096 } while_for_each_event_file();
2097
2098 if (call->event.funcs)
2099 __unregister_trace_event(&call->event);
2100 remove_event_from_tracers(call);
2101 list_del(&call->list);
2102 }
2103
2104 static int event_init(struct trace_event_call *call)
2105 {
2106 int ret = 0;
2107 const char *name;
2108
2109 name = trace_event_name(call);
2110 if (WARN_ON(!name))
2111 return -EINVAL;
2112
2113 if (call->class->raw_init) {
2114 ret = call->class->raw_init(call);
2115 if (ret < 0 && ret != -ENOSYS)
2116 pr_warn("Could not initialize trace events/%s\n", name);
2117 }
2118
2119 return ret;
2120 }
2121
2122 static int
2123 __register_event(struct trace_event_call *call, struct module *mod)
2124 {
2125 int ret;
2126
2127 ret = event_init(call);
2128 if (ret < 0)
2129 return ret;
2130
2131 list_add(&call->list, &ftrace_events);
2132 call->mod = mod;
2133
2134 return 0;
2135 }
2136
2137 static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2138 {
2139 int rlen;
2140 int elen;
2141
2142 /* Find the length of the eval value as a string */
2143 elen = snprintf(ptr, 0, "%ld", map->eval_value);
2144 /* Make sure there's enough room to replace the string with the value */
2145 if (len < elen)
2146 return NULL;
2147
2148 snprintf(ptr, elen + 1, "%ld", map->eval_value);
2149
2150 /* Get the rest of the string of ptr */
2151 rlen = strlen(ptr + len);
2152 memmove(ptr + elen, ptr + len, rlen);
2153 /* Make sure we end the new string */
2154 ptr[elen + rlen] = 0;
2155
2156 return ptr + elen;
2157 }
2158
2159 static void update_event_printk(struct trace_event_call *call,
2160 struct trace_eval_map *map)
2161 {
2162 char *ptr;
2163 int quote = 0;
2164 int len = strlen(map->eval_string);
2165
2166 for (ptr = call->print_fmt; *ptr; ptr++) {
2167 if (*ptr == '\\') {
2168 ptr++;
2169 /* paranoid */
2170 if (!*ptr)
2171 break;
2172 continue;
2173 }
2174 if (*ptr == '"') {
2175 quote ^= 1;
2176 continue;
2177 }
2178 if (quote)
2179 continue;
2180 if (isdigit(*ptr)) {
2181 /* skip numbers */
2182 do {
2183 ptr++;
2184 /* Check for alpha chars like ULL */
2185 } while (isalnum(*ptr));
2186 if (!*ptr)
2187 break;
2188 /*
2189 * A number must have some kind of delimiter after
2190 * it, and we can ignore that too.
2191 */
2192 continue;
2193 }
2194 if (isalpha(*ptr) || *ptr == '_') {
2195 if (strncmp(map->eval_string, ptr, len) == 0 &&
2196 !isalnum(ptr[len]) && ptr[len] != '_') {
2197 ptr = eval_replace(ptr, map, len);
2198 /* enum/sizeof string smaller than value */
2199 if (WARN_ON_ONCE(!ptr))
2200 return;
2201 /*
2202 * No need to decrement here, as eval_replace()
2203 * returns the pointer to the character passed
2204 * the eval, and two evals can not be placed
2205 * back to back without something in between.
2206 * We can skip that something in between.
2207 */
2208 continue;
2209 }
2210 skip_more:
2211 do {
2212 ptr++;
2213 } while (isalnum(*ptr) || *ptr == '_');
2214 if (!*ptr)
2215 break;
2216 /*
2217 * If what comes after this variable is a '.' or
2218 * '->' then we can continue to ignore that string.
2219 */
2220 if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2221 ptr += *ptr == '.' ? 1 : 2;
2222 if (!*ptr)
2223 break;
2224 goto skip_more;
2225 }
2226 /*
2227 * Once again, we can skip the delimiter that came
2228 * after the string.
2229 */
2230 continue;
2231 }
2232 }
2233 }
2234
2235 void trace_event_eval_update(struct trace_eval_map **map, int len)
2236 {
2237 struct trace_event_call *call, *p;
2238 const char *last_system = NULL;
2239 bool first = false;
2240 int last_i;
2241 int i;
2242
2243 down_write(&trace_event_sem);
2244 list_for_each_entry_safe(call, p, &ftrace_events, list) {
2245 /* events are usually grouped together with systems */
2246 if (!last_system || call->class->system != last_system) {
2247 first = true;
2248 last_i = 0;
2249 last_system = call->class->system;
2250 }
2251
2252 /*
2253 * Since calls are grouped by systems, the likelyhood that the
2254 * next call in the iteration belongs to the same system as the
2255 * previous call is high. As an optimization, we skip seaching
2256 * for a map[] that matches the call's system if the last call
2257 * was from the same system. That's what last_i is for. If the
2258 * call has the same system as the previous call, then last_i
2259 * will be the index of the first map[] that has a matching
2260 * system.
2261 */
2262 for (i = last_i; i < len; i++) {
2263 if (call->class->system == map[i]->system) {
2264 /* Save the first system if need be */
2265 if (first) {
2266 last_i = i;
2267 first = false;
2268 }
2269 update_event_printk(call, map[i]);
2270 }
2271 }
2272 }
2273 up_write(&trace_event_sem);
2274 }
2275
2276 static struct trace_event_file *
2277 trace_create_new_event(struct trace_event_call *call,
2278 struct trace_array *tr)
2279 {
2280 struct trace_event_file *file;
2281
2282 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2283 if (!file)
2284 return NULL;
2285
2286 file->event_call = call;
2287 file->tr = tr;
2288 atomic_set(&file->sm_ref, 0);
2289 atomic_set(&file->tm_ref, 0);
2290 INIT_LIST_HEAD(&file->triggers);
2291 list_add(&file->list, &tr->events);
2292
2293 return file;
2294 }
2295
2296 /* Add an event to a trace directory */
2297 static int
2298 __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2299 {
2300 struct trace_event_file *file;
2301
2302 file = trace_create_new_event(call, tr);
2303 if (!file)
2304 return -ENOMEM;
2305
2306 return event_create_dir(tr->event_dir, file);
2307 }
2308
2309 /*
2310 * Just create a decriptor for early init. A descriptor is required
2311 * for enabling events at boot. We want to enable events before
2312 * the filesystem is initialized.
2313 */
2314 static __init int
2315 __trace_early_add_new_event(struct trace_event_call *call,
2316 struct trace_array *tr)
2317 {
2318 struct trace_event_file *file;
2319
2320 file = trace_create_new_event(call, tr);
2321 if (!file)
2322 return -ENOMEM;
2323
2324 return 0;
2325 }
2326
2327 struct ftrace_module_file_ops;
2328 static void __add_event_to_tracers(struct trace_event_call *call);
2329
2330 /* Add an additional event_call dynamically */
2331 int trace_add_event_call(struct trace_event_call *call)
2332 {
2333 int ret;
2334 lockdep_assert_held(&event_mutex);
2335
2336 mutex_lock(&trace_types_lock);
2337
2338 ret = __register_event(call, NULL);
2339 if (ret >= 0)
2340 __add_event_to_tracers(call);
2341
2342 mutex_unlock(&trace_types_lock);
2343 return ret;
2344 }
2345
2346 /*
2347 * Must be called under locking of trace_types_lock, event_mutex and
2348 * trace_event_sem.
2349 */
2350 static void __trace_remove_event_call(struct trace_event_call *call)
2351 {
2352 event_remove(call);
2353 trace_destroy_fields(call);
2354 free_event_filter(call->filter);
2355 call->filter = NULL;
2356 }
2357
2358 static int probe_remove_event_call(struct trace_event_call *call)
2359 {
2360 struct trace_array *tr;
2361 struct trace_event_file *file;
2362
2363 #ifdef CONFIG_PERF_EVENTS
2364 if (call->perf_refcount)
2365 return -EBUSY;
2366 #endif
2367 do_for_each_event_file(tr, file) {
2368 if (file->event_call != call)
2369 continue;
2370 /*
2371 * We can't rely on ftrace_event_enable_disable(enable => 0)
2372 * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
2373 * TRACE_REG_UNREGISTER.
2374 */
2375 if (file->flags & EVENT_FILE_FL_ENABLED)
2376 return -EBUSY;
2377 /*
2378 * The do_for_each_event_file_safe() is
2379 * a double loop. After finding the call for this
2380 * trace_array, we use break to jump to the next
2381 * trace_array.
2382 */
2383 break;
2384 } while_for_each_event_file();
2385
2386 __trace_remove_event_call(call);
2387
2388 return 0;
2389 }
2390
2391 /* Remove an event_call */
2392 int trace_remove_event_call(struct trace_event_call *call)
2393 {
2394 int ret;
2395
2396 lockdep_assert_held(&event_mutex);
2397
2398 mutex_lock(&trace_types_lock);
2399 down_write(&trace_event_sem);
2400 ret = probe_remove_event_call(call);
2401 up_write(&trace_event_sem);
2402 mutex_unlock(&trace_types_lock);
2403
2404 return ret;
2405 }
2406
2407 #define for_each_event(event, start, end) \
2408 for (event = start; \
2409 (unsigned long)event < (unsigned long)end; \
2410 event++)
2411
2412 #ifdef CONFIG_MODULES
2413
2414 static void trace_module_add_events(struct module *mod)
2415 {
2416 struct trace_event_call **call, **start, **end;
2417
2418 if (!mod->num_trace_events)
2419 return;
2420
2421 /* Don't add infrastructure for mods without tracepoints */
2422 if (trace_module_has_bad_taint(mod)) {
2423 pr_err("%s: module has bad taint, not creating trace events\n",
2424 mod->name);
2425 return;
2426 }
2427
2428 start = mod->trace_events;
2429 end = mod->trace_events + mod->num_trace_events;
2430
2431 for_each_event(call, start, end) {
2432 __register_event(*call, mod);
2433 __add_event_to_tracers(*call);
2434 }
2435 }
2436
2437 static void trace_module_remove_events(struct module *mod)
2438 {
2439 struct trace_event_call *call, *p;
2440
2441 down_write(&trace_event_sem);
2442 list_for_each_entry_safe(call, p, &ftrace_events, list) {
2443 if (call->mod == mod)
2444 __trace_remove_event_call(call);
2445 }
2446 up_write(&trace_event_sem);
2447
2448 /*
2449 * It is safest to reset the ring buffer if the module being unloaded
2450 * registered any events that were used. The only worry is if
2451 * a new module gets loaded, and takes on the same id as the events
2452 * of this module. When printing out the buffer, traced events left
2453 * over from this module may be passed to the new module events and
2454 * unexpected results may occur.
2455 */
2456 tracing_reset_all_online_cpus();
2457 }
2458
2459 static int trace_module_notify(struct notifier_block *self,
2460 unsigned long val, void *data)
2461 {
2462 struct module *mod = data;
2463
2464 mutex_lock(&event_mutex);
2465 mutex_lock(&trace_types_lock);
2466 switch (val) {
2467 case MODULE_STATE_COMING:
2468 trace_module_add_events(mod);
2469 break;
2470 case MODULE_STATE_GOING:
2471 trace_module_remove_events(mod);
2472 break;
2473 }
2474 mutex_unlock(&trace_types_lock);
2475 mutex_unlock(&event_mutex);
2476
2477 return 0;
2478 }
2479
2480 static struct notifier_block trace_module_nb = {
2481 .notifier_call = trace_module_notify,
2482 .priority = 1, /* higher than trace.c module notify */
2483 };
2484 #endif /* CONFIG_MODULES */
2485
2486 /* Create a new event directory structure for a trace directory. */
2487 static void
2488 __trace_add_event_dirs(struct trace_array *tr)
2489 {
2490 struct trace_event_call *call;
2491 int ret;
2492
2493 list_for_each_entry(call, &ftrace_events, list) {
2494 ret = __trace_add_new_event(call, tr);
2495 if (ret < 0)
2496 pr_warn("Could not create directory for event %s\n",
2497 trace_event_name(call));
2498 }
2499 }
2500
2501 /* Returns any file that matches the system and event */
2502 struct trace_event_file *
2503 __find_event_file(struct trace_array *tr, const char *system, const char *event)
2504 {
2505 struct trace_event_file *file;
2506 struct trace_event_call *call;
2507 const char *name;
2508
2509 list_for_each_entry(file, &tr->events, list) {
2510
2511 call = file->event_call;
2512 name = trace_event_name(call);
2513
2514 if (!name || !call->class)
2515 continue;
2516
2517 if (strcmp(event, name) == 0 &&
2518 strcmp(system, call->class->system) == 0)
2519 return file;
2520 }
2521 return NULL;
2522 }
2523
2524 /* Returns valid trace event files that match system and event */
2525 struct trace_event_file *
2526 find_event_file(struct trace_array *tr, const char *system, const char *event)
2527 {
2528 struct trace_event_file *file;
2529
2530 file = __find_event_file(tr, system, event);
2531 if (!file || !file->event_call->class->reg ||
2532 file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
2533 return NULL;
2534
2535 return file;
2536 }
2537
2538 #ifdef CONFIG_DYNAMIC_FTRACE
2539
2540 /* Avoid typos */
2541 #define ENABLE_EVENT_STR "enable_event"
2542 #define DISABLE_EVENT_STR "disable_event"
2543
2544 struct event_probe_data {
2545 struct trace_event_file *file;
2546 unsigned long count;
2547 int ref;
2548 bool enable;
2549 };
2550
2551 static void update_event_probe(struct event_probe_data *data)
2552 {
2553 if (data->enable)
2554 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2555 else
2556 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2557 }
2558
2559 static void
2560 event_enable_probe(unsigned long ip, unsigned long parent_ip,
2561 struct trace_array *tr, struct ftrace_probe_ops *ops,
2562 void *data)
2563 {
2564 struct ftrace_func_mapper *mapper = data;
2565 struct event_probe_data *edata;
2566 void **pdata;
2567
2568 pdata = ftrace_func_mapper_find_ip(mapper, ip);
2569 if (!pdata || !*pdata)
2570 return;
2571
2572 edata = *pdata;
2573 update_event_probe(edata);
2574 }
2575
2576 static void
2577 event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
2578 struct trace_array *tr, struct ftrace_probe_ops *ops,
2579 void *data)
2580 {
2581 struct ftrace_func_mapper *mapper = data;
2582 struct event_probe_data *edata;
2583 void **pdata;
2584
2585 pdata = ftrace_func_mapper_find_ip(mapper, ip);
2586 if (!pdata || !*pdata)
2587 return;
2588
2589 edata = *pdata;
2590
2591 if (!edata->count)
2592 return;
2593
2594 /* Skip if the event is in a state we want to switch to */
2595 if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
2596 return;
2597
2598 if (edata->count != -1)
2599 (edata->count)--;
2600
2601 update_event_probe(edata);
2602 }
2603
2604 static int
2605 event_enable_print(struct seq_file *m, unsigned long ip,
2606 struct ftrace_probe_ops *ops, void *data)
2607 {
2608 struct ftrace_func_mapper *mapper = data;
2609 struct event_probe_data *edata;
2610 void **pdata;
2611
2612 pdata = ftrace_func_mapper_find_ip(mapper, ip);
2613
2614 if (WARN_ON_ONCE(!pdata || !*pdata))
2615 return 0;
2616
2617 edata = *pdata;
2618
2619 seq_printf(m, "%ps:", (void *)ip);
2620
2621 seq_printf(m, "%s:%s:%s",
2622 edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
2623 edata->file->event_call->class->system,
2624 trace_event_name(edata->file->event_call));
2625
2626 if (edata->count == -1)
2627 seq_puts(m, ":unlimited\n");
2628 else
2629 seq_printf(m, ":count=%ld\n", edata->count);
2630
2631 return 0;
2632 }
2633
2634 static int
2635 event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
2636 unsigned long ip, void *init_data, void **data)
2637 {
2638 struct ftrace_func_mapper *mapper = *data;
2639 struct event_probe_data *edata = init_data;
2640 int ret;
2641
2642 if (!mapper) {
2643 mapper = allocate_ftrace_func_mapper();
2644 if (!mapper)
2645 return -ENODEV;
2646 *data = mapper;
2647 }
2648
2649 ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
2650 if (ret < 0)
2651 return ret;
2652
2653 edata->ref++;
2654
2655 return 0;
2656 }
2657
2658 static int free_probe_data(void *data)
2659 {
2660 struct event_probe_data *edata = data;
2661
2662 edata->ref--;
2663 if (!edata->ref) {
2664 /* Remove the SOFT_MODE flag */
2665 __ftrace_event_enable_disable(edata->file, 0, 1);
2666 module_put(edata->file->event_call->mod);
2667 kfree(edata);
2668 }
2669 return 0;
2670 }
2671
2672 static void
2673 event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
2674 unsigned long ip, void *data)
2675 {
2676 struct ftrace_func_mapper *mapper = data;
2677 struct event_probe_data *edata;
2678
2679 if (!ip) {
2680 if (!mapper)
2681 return;
2682 free_ftrace_func_mapper(mapper, free_probe_data);
2683 return;
2684 }
2685
2686 edata = ftrace_func_mapper_remove_ip(mapper, ip);
2687
2688 if (WARN_ON_ONCE(!edata))
2689 return;
2690
2691 if (WARN_ON_ONCE(edata->ref <= 0))
2692 return;
2693
2694 free_probe_data(edata);
2695 }
2696
2697 static struct ftrace_probe_ops event_enable_probe_ops = {
2698 .func = event_enable_probe,
2699 .print = event_enable_print,
2700 .init = event_enable_init,
2701 .free = event_enable_free,
2702 };
2703
2704 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2705 .func = event_enable_count_probe,
2706 .print = event_enable_print,
2707 .init = event_enable_init,
2708 .free = event_enable_free,
2709 };
2710
2711 static struct ftrace_probe_ops event_disable_probe_ops = {
2712 .func = event_enable_probe,
2713 .print = event_enable_print,
2714 .init = event_enable_init,
2715 .free = event_enable_free,
2716 };
2717
2718 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2719 .func = event_enable_count_probe,
2720 .print = event_enable_print,
2721 .init = event_enable_init,
2722 .free = event_enable_free,
2723 };
2724
2725 static int
2726 event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
2727 char *glob, char *cmd, char *param, int enabled)
2728 {
2729 struct trace_event_file *file;
2730 struct ftrace_probe_ops *ops;
2731 struct event_probe_data *data;
2732 const char *system;
2733 const char *event;
2734 char *number;
2735 bool enable;
2736 int ret;
2737
2738 if (!tr)
2739 return -ENODEV;
2740
2741 /* hash funcs only work with set_ftrace_filter */
2742 if (!enabled || !param)
2743 return -EINVAL;
2744
2745 system = strsep(&param, ":");
2746 if (!param)
2747 return -EINVAL;
2748
2749 event = strsep(&param, ":");
2750
2751 mutex_lock(&event_mutex);
2752
2753 ret = -EINVAL;
2754 file = find_event_file(tr, system, event);
2755 if (!file)
2756 goto out;
2757
2758 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2759
2760 if (enable)
2761 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2762 else
2763 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2764
2765 if (glob[0] == '!') {
2766 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
2767 goto out;
2768 }
2769
2770 ret = -ENOMEM;
2771
2772 data = kzalloc(sizeof(*data), GFP_KERNEL);
2773 if (!data)
2774 goto out;
2775
2776 data->enable = enable;
2777 data->count = -1;
2778 data->file = file;
2779
2780 if (!param)
2781 goto out_reg;
2782
2783 number = strsep(&param, ":");
2784
2785 ret = -EINVAL;
2786 if (!strlen(number))
2787 goto out_free;
2788
2789 /*
2790 * We use the callback data field (which is a pointer)
2791 * as our counter.
2792 */
2793 ret = kstrtoul(number, 0, &data->count);
2794 if (ret)
2795 goto out_free;
2796
2797 out_reg:
2798 /* Don't let event modules unload while probe registered */
2799 ret = try_module_get(file->event_call->mod);
2800 if (!ret) {
2801 ret = -EBUSY;
2802 goto out_free;
2803 }
2804
2805 ret = __ftrace_event_enable_disable(file, 1, 1);
2806 if (ret < 0)
2807 goto out_put;
2808
2809 ret = register_ftrace_function_probe(glob, tr, ops, data);
2810 /*
2811 * The above returns on success the # of functions enabled,
2812 * but if it didn't find any functions it returns zero.
2813 * Consider no functions a failure too.
2814 */
2815 if (!ret) {
2816 ret = -ENOENT;
2817 goto out_disable;
2818 } else if (ret < 0)
2819 goto out_disable;
2820 /* Just return zero, not the number of enabled functions */
2821 ret = 0;
2822 out:
2823 mutex_unlock(&event_mutex);
2824 return ret;
2825
2826 out_disable:
2827 __ftrace_event_enable_disable(file, 0, 1);
2828 out_put:
2829 module_put(file->event_call->mod);
2830 out_free:
2831 kfree(data);
2832 goto out;
2833 }
2834
2835 static struct ftrace_func_command event_enable_cmd = {
2836 .name = ENABLE_EVENT_STR,
2837 .func = event_enable_func,
2838 };
2839
2840 static struct ftrace_func_command event_disable_cmd = {
2841 .name = DISABLE_EVENT_STR,
2842 .func = event_enable_func,
2843 };
2844
2845 static __init int register_event_cmds(void)
2846 {
2847 int ret;
2848
2849 ret = register_ftrace_command(&event_enable_cmd);
2850 if (WARN_ON(ret < 0))
2851 return ret;
2852 ret = register_ftrace_command(&event_disable_cmd);
2853 if (WARN_ON(ret < 0))
2854 unregister_ftrace_command(&event_enable_cmd);
2855 return ret;
2856 }
2857 #else
2858 static inline int register_event_cmds(void) { return 0; }
2859 #endif /* CONFIG_DYNAMIC_FTRACE */
2860
2861 /*
2862 * The top level array has already had its trace_event_file
2863 * descriptors created in order to allow for early events to
2864 * be recorded. This function is called after the tracefs has been
2865 * initialized, and we now have to create the files associated
2866 * to the events.
2867 */
2868 static __init void
2869 __trace_early_add_event_dirs(struct trace_array *tr)
2870 {
2871 struct trace_event_file *file;
2872 int ret;
2873
2874
2875 list_for_each_entry(file, &tr->events, list) {
2876 ret = event_create_dir(tr->event_dir, file);
2877 if (ret < 0)
2878 pr_warn("Could not create directory for event %s\n",
2879 trace_event_name(file->event_call));
2880 }
2881 }
2882
2883 /*
2884 * For early boot up, the top trace array requires to have
2885 * a list of events that can be enabled. This must be done before
2886 * the filesystem is set up in order to allow events to be traced
2887 * early.
2888 */
2889 static __init void
2890 __trace_early_add_events(struct trace_array *tr)
2891 {
2892 struct trace_event_call *call;
2893 int ret;
2894
2895 list_for_each_entry(call, &ftrace_events, list) {
2896 /* Early boot up should not have any modules loaded */
2897 if (WARN_ON_ONCE(call->mod))
2898 continue;
2899
2900 ret = __trace_early_add_new_event(call, tr);
2901 if (ret < 0)
2902 pr_warn("Could not create early event %s\n",
2903 trace_event_name(call));
2904 }
2905 }
2906
2907 /* Remove the event directory structure for a trace directory. */
2908 static void
2909 __trace_remove_event_dirs(struct trace_array *tr)
2910 {
2911 struct trace_event_file *file, *next;
2912
2913 list_for_each_entry_safe(file, next, &tr->events, list)
2914 remove_event_file_dir(file);
2915 }
2916
2917 static void __add_event_to_tracers(struct trace_event_call *call)
2918 {
2919 struct trace_array *tr;
2920
2921 list_for_each_entry(tr, &ftrace_trace_arrays, list)
2922 __trace_add_new_event(call, tr);
2923 }
2924
2925 extern struct trace_event_call *__start_ftrace_events[];
2926 extern struct trace_event_call *__stop_ftrace_events[];
2927
2928 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2929
2930 static __init int setup_trace_event(char *str)
2931 {
2932 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2933 ring_buffer_expanded = true;
2934 tracing_selftest_disabled = true;
2935
2936 return 1;
2937 }
2938 __setup("trace_event=", setup_trace_event);
2939
2940 /* Expects to have event_mutex held when called */
2941 static int
2942 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2943 {
2944 struct dentry *d_events;
2945 struct dentry *entry;
2946
2947 entry = tracefs_create_file("set_event", 0644, parent,
2948 tr, &ftrace_set_event_fops);
2949 if (!entry) {
2950 pr_warn("Could not create tracefs 'set_event' entry\n");
2951 return -ENOMEM;
2952 }
2953
2954 d_events = tracefs_create_dir("events", parent);
2955 if (!d_events) {
2956 pr_warn("Could not create tracefs 'events' directory\n");
2957 return -ENOMEM;
2958 }
2959
2960 entry = trace_create_file("enable", 0644, d_events,
2961 tr, &ftrace_tr_enable_fops);
2962 if (!entry) {
2963 pr_warn("Could not create tracefs 'enable' entry\n");
2964 return -ENOMEM;
2965 }
2966
2967 /* There are not as crucial, just warn if they are not created */
2968
2969 entry = tracefs_create_file("set_event_pid", 0644, parent,
2970 tr, &ftrace_set_event_pid_fops);
2971 if (!entry)
2972 pr_warn("Could not create tracefs 'set_event_pid' entry\n");
2973
2974 /* ring buffer internal formats */
2975 entry = trace_create_file("header_page", 0444, d_events,
2976 ring_buffer_print_page_header,
2977 &ftrace_show_header_fops);
2978 if (!entry)
2979 pr_warn("Could not create tracefs 'header_page' entry\n");
2980
2981 entry = trace_create_file("header_event", 0444, d_events,
2982 ring_buffer_print_entry_header,
2983 &ftrace_show_header_fops);
2984 if (!entry)
2985 pr_warn("Could not create tracefs 'header_event' entry\n");
2986
2987 tr->event_dir = d_events;
2988
2989 return 0;
2990 }
2991
2992 /**
2993 * event_trace_add_tracer - add a instance of a trace_array to events
2994 * @parent: The parent dentry to place the files/directories for events in
2995 * @tr: The trace array associated with these events
2996 *
2997 * When a new instance is created, it needs to set up its events
2998 * directory, as well as other files associated with events. It also
2999 * creates the event hierachry in the @parent/events directory.
3000 *
3001 * Returns 0 on success.
3002 *
3003 * Must be called with event_mutex held.
3004 */
3005 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
3006 {
3007 int ret;
3008
3009 lockdep_assert_held(&event_mutex);
3010
3011 ret = create_event_toplevel_files(parent, tr);
3012 if (ret)
3013 goto out;
3014
3015 down_write(&trace_event_sem);
3016 __trace_add_event_dirs(tr);
3017 up_write(&trace_event_sem);
3018
3019 out:
3020 return ret;
3021 }
3022
3023 /*
3024 * The top trace array already had its file descriptors created.
3025 * Now the files themselves need to be created.
3026 */
3027 static __init int
3028 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
3029 {
3030 int ret;
3031
3032 mutex_lock(&event_mutex);
3033
3034 ret = create_event_toplevel_files(parent, tr);
3035 if (ret)
3036 goto out_unlock;
3037
3038 down_write(&trace_event_sem);
3039 __trace_early_add_event_dirs(tr);
3040 up_write(&trace_event_sem);
3041
3042 out_unlock:
3043 mutex_unlock(&event_mutex);
3044
3045 return ret;
3046 }
3047
3048 /* Must be called with event_mutex held */
3049 int event_trace_del_tracer(struct trace_array *tr)
3050 {
3051 lockdep_assert_held(&event_mutex);
3052
3053 /* Disable any event triggers and associated soft-disabled events */
3054 clear_event_triggers(tr);
3055
3056 /* Clear the pid list */
3057 __ftrace_clear_event_pids(tr);
3058
3059 /* Disable any running events */
3060 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3061
3062 /* Make sure no more events are being executed */
3063 tracepoint_synchronize_unregister();
3064
3065 down_write(&trace_event_sem);
3066 __trace_remove_event_dirs(tr);
3067 tracefs_remove_recursive(tr->event_dir);
3068 up_write(&trace_event_sem);
3069
3070 tr->event_dir = NULL;
3071
3072 return 0;
3073 }
3074
3075 static __init int event_trace_memsetup(void)
3076 {
3077 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3078 file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3079 return 0;
3080 }
3081
3082 static __init void
3083 early_enable_events(struct trace_array *tr, bool disable_first)
3084 {
3085 char *buf = bootup_event_buf;
3086 char *token;
3087 int ret;
3088
3089 while (true) {
3090 token = strsep(&buf, ",");
3091
3092 if (!token)
3093 break;
3094
3095 if (*token) {
3096 /* Restarting syscalls requires that we stop them first */
3097 if (disable_first)
3098 ftrace_set_clr_event(tr, token, 0);
3099
3100 ret = ftrace_set_clr_event(tr, token, 1);
3101 if (ret)
3102 pr_warn("Failed to enable trace event: %s\n", token);
3103 }
3104
3105 /* Put back the comma to allow this to be called again */
3106 if (buf)
3107 *(buf - 1) = ',';
3108 }
3109 }
3110
3111 static __init int event_trace_enable(void)
3112 {
3113 struct trace_array *tr = top_trace_array();
3114 struct trace_event_call **iter, *call;
3115 int ret;
3116
3117 if (!tr)
3118 return -ENODEV;
3119
3120 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3121
3122 call = *iter;
3123 ret = event_init(call);
3124 if (!ret)
3125 list_add(&call->list, &ftrace_events);
3126 }
3127
3128 /*
3129 * We need the top trace array to have a working set of trace
3130 * points at early init, before the debug files and directories
3131 * are created. Create the file entries now, and attach them
3132 * to the actual file dentries later.
3133 */
3134 __trace_early_add_events(tr);
3135
3136 early_enable_events(tr, false);
3137
3138 trace_printk_start_comm();
3139
3140 register_event_cmds();
3141
3142 register_trigger_cmds();
3143
3144 return 0;
3145 }
3146
3147 /*
3148 * event_trace_enable() is called from trace_event_init() first to
3149 * initialize events and perhaps start any events that are on the
3150 * command line. Unfortunately, there are some events that will not
3151 * start this early, like the system call tracepoints that need
3152 * to set the TIF_SYSCALL_TRACEPOINT flag of pid 1. But event_trace_enable()
3153 * is called before pid 1 starts, and this flag is never set, making
3154 * the syscall tracepoint never get reached, but the event is enabled
3155 * regardless (and not doing anything).
3156 */
3157 static __init int event_trace_enable_again(void)
3158 {
3159 struct trace_array *tr;
3160
3161 tr = top_trace_array();
3162 if (!tr)
3163 return -ENODEV;
3164
3165 early_enable_events(tr, true);
3166
3167 return 0;
3168 }
3169
3170 early_initcall(event_trace_enable_again);
3171
3172 __init int event_trace_init(void)
3173 {
3174 struct trace_array *tr;
3175 struct dentry *d_tracer;
3176 struct dentry *entry;
3177 int ret;
3178
3179 tr = top_trace_array();
3180 if (!tr)
3181 return -ENODEV;
3182
3183 d_tracer = tracing_init_dentry();
3184 if (IS_ERR(d_tracer))
3185 return 0;
3186
3187 entry = tracefs_create_file("available_events", 0444, d_tracer,
3188 tr, &ftrace_avail_fops);
3189 if (!entry)
3190 pr_warn("Could not create tracefs 'available_events' entry\n");
3191
3192 if (trace_define_generic_fields())
3193 pr_warn("tracing: Failed to allocated generic fields");
3194
3195 if (trace_define_common_fields())
3196 pr_warn("tracing: Failed to allocate common fields");
3197
3198 ret = early_event_add_tracer(d_tracer, tr);
3199 if (ret)
3200 return ret;
3201
3202 #ifdef CONFIG_MODULES
3203 ret = register_module_notifier(&trace_module_nb);
3204 if (ret)
3205 pr_warn("Failed to register trace events module notifier\n");
3206 #endif
3207 return 0;
3208 }
3209
3210 void __init trace_event_init(void)
3211 {
3212 event_trace_memsetup();
3213 init_ftrace_syscalls();
3214 event_trace_enable();
3215 }
3216
3217 #ifdef CONFIG_EVENT_TRACE_STARTUP_TEST
3218
3219 static DEFINE_SPINLOCK(test_spinlock);
3220 static DEFINE_SPINLOCK(test_spinlock_irq);
3221 static DEFINE_MUTEX(test_mutex);
3222
3223 static __init void test_work(struct work_struct *dummy)
3224 {
3225 spin_lock(&test_spinlock);
3226 spin_lock_irq(&test_spinlock_irq);
3227 udelay(1);
3228 spin_unlock_irq(&test_spinlock_irq);
3229 spin_unlock(&test_spinlock);
3230
3231 mutex_lock(&test_mutex);
3232 msleep(1);
3233 mutex_unlock(&test_mutex);
3234 }
3235
3236 static __init int event_test_thread(void *unused)
3237 {
3238 void *test_malloc;
3239
3240 test_malloc = kmalloc(1234, GFP_KERNEL);
3241 if (!test_malloc)
3242 pr_info("failed to kmalloc\n");
3243
3244 schedule_on_each_cpu(test_work);
3245
3246 kfree(test_malloc);
3247
3248 set_current_state(TASK_INTERRUPTIBLE);
3249 while (!kthread_should_stop()) {
3250 schedule();
3251 set_current_state(TASK_INTERRUPTIBLE);
3252 }
3253 __set_current_state(TASK_RUNNING);
3254
3255 return 0;
3256 }
3257
3258 /*
3259 * Do various things that may trigger events.
3260 */
3261 static __init void event_test_stuff(void)
3262 {
3263 struct task_struct *test_thread;
3264
3265 test_thread = kthread_run(event_test_thread, NULL, "test-events");
3266 msleep(1);
3267 kthread_stop(test_thread);
3268 }
3269
3270 /*
3271 * For every trace event defined, we will test each trace point separately,
3272 * and then by groups, and finally all trace points.
3273 */
3274 static __init void event_trace_self_tests(void)
3275 {
3276 struct trace_subsystem_dir *dir;
3277 struct trace_event_file *file;
3278 struct trace_event_call *call;
3279 struct event_subsystem *system;
3280 struct trace_array *tr;
3281 int ret;
3282
3283 tr = top_trace_array();
3284 if (!tr)
3285 return;
3286
3287 pr_info("Running tests on trace events:\n");
3288
3289 list_for_each_entry(file, &tr->events, list) {
3290
3291 call = file->event_call;
3292
3293 /* Only test those that have a probe */
3294 if (!call->class || !call->class->probe)
3295 continue;
3296
3297 /*
3298 * Testing syscall events here is pretty useless, but
3299 * we still do it if configured. But this is time consuming.
3300 * What we really need is a user thread to perform the
3301 * syscalls as we test.
3302 */
3303 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
3304 if (call->class->system &&
3305 strcmp(call->class->system, "syscalls") == 0)
3306 continue;
3307 #endif
3308
3309 pr_info("Testing event %s: ", trace_event_name(call));
3310
3311 /*
3312 * If an event is already enabled, someone is using
3313 * it and the self test should not be on.
3314 */
3315 if (file->flags & EVENT_FILE_FL_ENABLED) {
3316 pr_warn("Enabled event during self test!\n");
3317 WARN_ON_ONCE(1);
3318 continue;
3319 }
3320
3321 ftrace_event_enable_disable(file, 1);
3322 event_test_stuff();
3323 ftrace_event_enable_disable(file, 0);
3324
3325 pr_cont("OK\n");
3326 }
3327
3328 /* Now test at the sub system level */
3329
3330 pr_info("Running tests on trace event systems:\n");
3331
3332 list_for_each_entry(dir, &tr->systems, list) {
3333
3334 system = dir->subsystem;
3335
3336 /* the ftrace system is special, skip it */
3337 if (strcmp(system->name, "ftrace") == 0)
3338 continue;
3339
3340 pr_info("Testing event system %s: ", system->name);
3341
3342 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
3343 if (WARN_ON_ONCE(ret)) {
3344 pr_warn("error enabling system %s\n",
3345 system->name);
3346 continue;
3347 }
3348
3349 event_test_stuff();
3350
3351 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
3352 if (WARN_ON_ONCE(ret)) {
3353 pr_warn("error disabling system %s\n",
3354 system->name);
3355 continue;
3356 }
3357
3358 pr_cont("OK\n");
3359 }
3360
3361 /* Test with all events enabled */
3362
3363 pr_info("Running tests on all trace events:\n");
3364 pr_info("Testing all events: ");
3365
3366 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
3367 if (WARN_ON_ONCE(ret)) {
3368 pr_warn("error enabling all events\n");
3369 return;
3370 }
3371
3372 event_test_stuff();
3373
3374 /* reset sysname */
3375 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
3376 if (WARN_ON_ONCE(ret)) {
3377 pr_warn("error disabling all events\n");
3378 return;
3379 }
3380
3381 pr_cont("OK\n");
3382 }
3383
3384 #ifdef CONFIG_FUNCTION_TRACER
3385
3386 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
3387
3388 static struct trace_event_file event_trace_file __initdata;
3389
3390 static void __init
3391 function_test_events_call(unsigned long ip, unsigned long parent_ip,
3392 struct ftrace_ops *op, struct pt_regs *pt_regs)
3393 {
3394 struct ring_buffer_event *event;
3395 struct ring_buffer *buffer;
3396 struct ftrace_entry *entry;
3397 unsigned long flags;
3398 long disabled;
3399 int cpu;
3400 int pc;
3401
3402 pc = preempt_count();
3403 preempt_disable_notrace();
3404 cpu = raw_smp_processor_id();
3405 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
3406
3407 if (disabled != 1)
3408 goto out;
3409
3410 local_save_flags(flags);
3411
3412 event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
3413 TRACE_FN, sizeof(*entry),
3414 flags, pc);
3415 if (!event)
3416 goto out;
3417 entry = ring_buffer_event_data(event);
3418 entry->ip = ip;
3419 entry->parent_ip = parent_ip;
3420
3421 event_trigger_unlock_commit(&event_trace_file, buffer, event,
3422 entry, flags, pc);
3423 out:
3424 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
3425 preempt_enable_notrace();
3426 }
3427
3428 static struct ftrace_ops trace_ops __initdata =
3429 {
3430 .func = function_test_events_call,
3431 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
3432 };
3433
3434 static __init void event_trace_self_test_with_function(void)
3435 {
3436 int ret;
3437
3438 event_trace_file.tr = top_trace_array();
3439 if (WARN_ON(!event_trace_file.tr))
3440 return;
3441
3442 ret = register_ftrace_function(&trace_ops);
3443 if (WARN_ON(ret < 0)) {
3444 pr_info("Failed to enable function tracer for event tests\n");
3445 return;
3446 }
3447 pr_info("Running tests again, along with the function tracer\n");
3448 event_trace_self_tests();
3449 unregister_ftrace_function(&trace_ops);
3450 }
3451 #else
3452 static __init void event_trace_self_test_with_function(void)
3453 {
3454 }
3455 #endif
3456
3457 static __init int event_trace_self_tests_init(void)
3458 {
3459 if (!tracing_selftest_disabled) {
3460 event_trace_self_tests();
3461 event_trace_self_test_with_function();
3462 }
3463
3464 return 0;
3465 }
3466
3467 late_initcall(event_trace_self_tests_init);
3468
3469 #endif
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