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1/*
2 * trace_events_trigger - trace event triggers
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
19 */
20
21#include <linux/module.h>
22#include <linux/ctype.h>
23#include <linux/mutex.h>
24#include <linux/slab.h>
25
26#include "trace.h"
27
28static LIST_HEAD(trigger_commands);
29static DEFINE_MUTEX(trigger_cmd_mutex);
30
31static void
32trigger_data_free(struct event_trigger_data *data)
33{
34 if (data->cmd_ops->set_filter)
35 data->cmd_ops->set_filter(NULL, data, NULL);
36
37 synchronize_sched(); /* make sure current triggers exit before free */
38 kfree(data);
39}
40
41/**
42 * event_triggers_call - Call triggers associated with a trace event
43 * @file: The ftrace_event_file associated with the event
44 * @rec: The trace entry for the event, NULL for unconditional invocation
45 *
46 * For each trigger associated with an event, invoke the trigger
47 * function registered with the associated trigger command. If rec is
48 * non-NULL, it means that the trigger requires further processing and
49 * shouldn't be unconditionally invoked. If rec is non-NULL and the
50 * trigger has a filter associated with it, rec will checked against
51 * the filter and if the record matches the trigger will be invoked.
52 * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
53 * in any case until the current event is written, the trigger
54 * function isn't invoked but the bit associated with the deferred
55 * trigger is set in the return value.
56 *
57 * Returns an enum event_trigger_type value containing a set bit for
58 * any trigger that should be deferred, ETT_NONE if nothing to defer.
59 *
60 * Called from tracepoint handlers (with rcu_read_lock_sched() held).
61 *
62 * Return: an enum event_trigger_type value containing a set bit for
63 * any trigger that should be deferred, ETT_NONE if nothing to defer.
64 */
65enum event_trigger_type
66event_triggers_call(struct ftrace_event_file *file, void *rec)
67{
68 struct event_trigger_data *data;
69 enum event_trigger_type tt = ETT_NONE;
70 struct event_filter *filter;
71
72 if (list_empty(&file->triggers))
73 return tt;
74
75 list_for_each_entry_rcu(data, &file->triggers, list) {
76 if (!rec) {
77 data->ops->func(data);
78 continue;
79 }
80 filter = rcu_dereference_sched(data->filter);
81 if (filter && !filter_match_preds(filter, rec))
82 continue;
83 if (data->cmd_ops->post_trigger) {
84 tt |= data->cmd_ops->trigger_type;
85 continue;
86 }
87 data->ops->func(data);
88 }
89 return tt;
90}
91EXPORT_SYMBOL_GPL(event_triggers_call);
92
93/**
94 * event_triggers_post_call - Call 'post_triggers' for a trace event
95 * @file: The ftrace_event_file associated with the event
96 * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
97 *
98 * For each trigger associated with an event, invoke the trigger
99 * function registered with the associated trigger command, if the
100 * corresponding bit is set in the tt enum passed into this function.
101 * See @event_triggers_call for details on how those bits are set.
102 *
103 * Called from tracepoint handlers (with rcu_read_lock_sched() held).
104 */
105void
106event_triggers_post_call(struct ftrace_event_file *file,
107 enum event_trigger_type tt)
108{
109 struct event_trigger_data *data;
110
111 list_for_each_entry_rcu(data, &file->triggers, list) {
112 if (data->cmd_ops->trigger_type & tt)
113 data->ops->func(data);
114 }
115}
116EXPORT_SYMBOL_GPL(event_triggers_post_call);
117
118#define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
119
120static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
121{
122 struct ftrace_event_file *event_file = event_file_data(m->private);
123
124 if (t == SHOW_AVAILABLE_TRIGGERS)
125 return NULL;
126
127 return seq_list_next(t, &event_file->triggers, pos);
128}
129
130static void *trigger_start(struct seq_file *m, loff_t *pos)
131{
132 struct ftrace_event_file *event_file;
133
134 /* ->stop() is called even if ->start() fails */
135 mutex_lock(&event_mutex);
136 event_file = event_file_data(m->private);
137 if (unlikely(!event_file))
138 return ERR_PTR(-ENODEV);
139
140 if (list_empty(&event_file->triggers))
141 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
142
143 return seq_list_start(&event_file->triggers, *pos);
144}
145
146static void trigger_stop(struct seq_file *m, void *t)
147{
148 mutex_unlock(&event_mutex);
149}
150
151static int trigger_show(struct seq_file *m, void *v)
152{
153 struct event_trigger_data *data;
154 struct event_command *p;
155
156 if (v == SHOW_AVAILABLE_TRIGGERS) {
157 seq_puts(m, "# Available triggers:\n");
158 seq_putc(m, '#');
159 mutex_lock(&trigger_cmd_mutex);
160 list_for_each_entry_reverse(p, &trigger_commands, list)
161 seq_printf(m, " %s", p->name);
162 seq_putc(m, '\n');
163 mutex_unlock(&trigger_cmd_mutex);
164 return 0;
165 }
166
167 data = list_entry(v, struct event_trigger_data, list);
168 data->ops->print(m, data->ops, data);
169
170 return 0;
171}
172
173static const struct seq_operations event_triggers_seq_ops = {
174 .start = trigger_start,
175 .next = trigger_next,
176 .stop = trigger_stop,
177 .show = trigger_show,
178};
179
180static int event_trigger_regex_open(struct inode *inode, struct file *file)
181{
182 int ret = 0;
183
184 mutex_lock(&event_mutex);
185
186 if (unlikely(!event_file_data(file))) {
187 mutex_unlock(&event_mutex);
188 return -ENODEV;
189 }
190
191 if (file->f_mode & FMODE_READ) {
192 ret = seq_open(file, &event_triggers_seq_ops);
193 if (!ret) {
194 struct seq_file *m = file->private_data;
195 m->private = file;
196 }
197 }
198
199 mutex_unlock(&event_mutex);
200
201 return ret;
202}
203
204static int trigger_process_regex(struct ftrace_event_file *file, char *buff)
205{
206 char *command, *next = buff;
207 struct event_command *p;
208 int ret = -EINVAL;
209
210 command = strsep(&next, ": \t");
211 command = (command[0] != '!') ? command : command + 1;
212
213 mutex_lock(&trigger_cmd_mutex);
214 list_for_each_entry(p, &trigger_commands, list) {
215 if (strcmp(p->name, command) == 0) {
216 ret = p->func(p, file, buff, command, next);
217 goto out_unlock;
218 }
219 }
220 out_unlock:
221 mutex_unlock(&trigger_cmd_mutex);
222
223 return ret;
224}
225
226static ssize_t event_trigger_regex_write(struct file *file,
227 const char __user *ubuf,
228 size_t cnt, loff_t *ppos)
229{
230 struct ftrace_event_file *event_file;
231 ssize_t ret;
232 char *buf;
233
234 if (!cnt)
235 return 0;
236
237 if (cnt >= PAGE_SIZE)
238 return -EINVAL;
239
240 buf = (char *)__get_free_page(GFP_TEMPORARY);
241 if (!buf)
242 return -ENOMEM;
243
244 if (copy_from_user(buf, ubuf, cnt)) {
245 free_page((unsigned long)buf);
246 return -EFAULT;
247 }
248 buf[cnt] = '\0';
249 strim(buf);
250
251 mutex_lock(&event_mutex);
252 event_file = event_file_data(file);
253 if (unlikely(!event_file)) {
254 mutex_unlock(&event_mutex);
255 free_page((unsigned long)buf);
256 return -ENODEV;
257 }
258 ret = trigger_process_regex(event_file, buf);
259 mutex_unlock(&event_mutex);
260
261 free_page((unsigned long)buf);
262 if (ret < 0)
263 goto out;
264
265 *ppos += cnt;
266 ret = cnt;
267 out:
268 return ret;
269}
270
271static int event_trigger_regex_release(struct inode *inode, struct file *file)
272{
273 mutex_lock(&event_mutex);
274
275 if (file->f_mode & FMODE_READ)
276 seq_release(inode, file);
277
278 mutex_unlock(&event_mutex);
279
280 return 0;
281}
282
283static ssize_t
284event_trigger_write(struct file *filp, const char __user *ubuf,
285 size_t cnt, loff_t *ppos)
286{
287 return event_trigger_regex_write(filp, ubuf, cnt, ppos);
288}
289
290static int
291event_trigger_open(struct inode *inode, struct file *filp)
292{
293 return event_trigger_regex_open(inode, filp);
294}
295
296static int
297event_trigger_release(struct inode *inode, struct file *file)
298{
299 return event_trigger_regex_release(inode, file);
300}
301
302const struct file_operations event_trigger_fops = {
303 .open = event_trigger_open,
304 .read = seq_read,
305 .write = event_trigger_write,
306 .llseek = tracing_lseek,
307 .release = event_trigger_release,
308};
309
310/*
311 * Currently we only register event commands from __init, so mark this
312 * __init too.
313 */
314static __init int register_event_command(struct event_command *cmd)
315{
316 struct event_command *p;
317 int ret = 0;
318
319 mutex_lock(&trigger_cmd_mutex);
320 list_for_each_entry(p, &trigger_commands, list) {
321 if (strcmp(cmd->name, p->name) == 0) {
322 ret = -EBUSY;
323 goto out_unlock;
324 }
325 }
326 list_add(&cmd->list, &trigger_commands);
327 out_unlock:
328 mutex_unlock(&trigger_cmd_mutex);
329
330 return ret;
331}
332
333/*
334 * Currently we only unregister event commands from __init, so mark
335 * this __init too.
336 */
337static __init int unregister_event_command(struct event_command *cmd)
338{
339 struct event_command *p, *n;
340 int ret = -ENODEV;
341
342 mutex_lock(&trigger_cmd_mutex);
343 list_for_each_entry_safe(p, n, &trigger_commands, list) {
344 if (strcmp(cmd->name, p->name) == 0) {
345 ret = 0;
346 list_del_init(&p->list);
347 goto out_unlock;
348 }
349 }
350 out_unlock:
351 mutex_unlock(&trigger_cmd_mutex);
352
353 return ret;
354}
355
356/**
357 * event_trigger_print - Generic event_trigger_ops @print implementation
358 * @name: The name of the event trigger
359 * @m: The seq_file being printed to
360 * @data: Trigger-specific data
361 * @filter_str: filter_str to print, if present
362 *
363 * Common implementation for event triggers to print themselves.
364 *
365 * Usually wrapped by a function that simply sets the @name of the
366 * trigger command and then invokes this.
367 *
368 * Return: 0 on success, errno otherwise
369 */
370static int
371event_trigger_print(const char *name, struct seq_file *m,
372 void *data, char *filter_str)
373{
374 long count = (long)data;
375
376 seq_printf(m, "%s", name);
377
378 if (count == -1)
379 seq_puts(m, ":unlimited");
380 else
381 seq_printf(m, ":count=%ld", count);
382
383 if (filter_str)
384 seq_printf(m, " if %s\n", filter_str);
385 else
386 seq_puts(m, "\n");
387
388 return 0;
389}
390
391/**
392 * event_trigger_init - Generic event_trigger_ops @init implementation
393 * @ops: The trigger ops associated with the trigger
394 * @data: Trigger-specific data
395 *
396 * Common implementation of event trigger initialization.
397 *
398 * Usually used directly as the @init method in event trigger
399 * implementations.
400 *
401 * Return: 0 on success, errno otherwise
402 */
403static int
404event_trigger_init(struct event_trigger_ops *ops,
405 struct event_trigger_data *data)
406{
407 data->ref++;
408 return 0;
409}
410
411/**
412 * event_trigger_free - Generic event_trigger_ops @free implementation
413 * @ops: The trigger ops associated with the trigger
414 * @data: Trigger-specific data
415 *
416 * Common implementation of event trigger de-initialization.
417 *
418 * Usually used directly as the @free method in event trigger
419 * implementations.
420 */
421static void
422event_trigger_free(struct event_trigger_ops *ops,
423 struct event_trigger_data *data)
424{
425 if (WARN_ON_ONCE(data->ref <= 0))
426 return;
427
428 data->ref--;
429 if (!data->ref)
430 trigger_data_free(data);
431}
432
433static int trace_event_trigger_enable_disable(struct ftrace_event_file *file,
434 int trigger_enable)
435{
436 int ret = 0;
437
438 if (trigger_enable) {
439 if (atomic_inc_return(&file->tm_ref) > 1)
440 return ret;
441 set_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, &file->flags);
442 ret = trace_event_enable_disable(file, 1, 1);
443 } else {
444 if (atomic_dec_return(&file->tm_ref) > 0)
445 return ret;
446 clear_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, &file->flags);
447 ret = trace_event_enable_disable(file, 0, 1);
448 }
449
450 return ret;
451}
452
453/**
454 * clear_event_triggers - Clear all triggers associated with a trace array
455 * @tr: The trace array to clear
456 *
457 * For each trigger, the triggering event has its tm_ref decremented
458 * via trace_event_trigger_enable_disable(), and any associated event
459 * (in the case of enable/disable_event triggers) will have its sm_ref
460 * decremented via free()->trace_event_enable_disable(). That
461 * combination effectively reverses the soft-mode/trigger state added
462 * by trigger registration.
463 *
464 * Must be called with event_mutex held.
465 */
466void
467clear_event_triggers(struct trace_array *tr)
468{
469 struct ftrace_event_file *file;
470
471 list_for_each_entry(file, &tr->events, list) {
472 struct event_trigger_data *data;
473 list_for_each_entry_rcu(data, &file->triggers, list) {
474 trace_event_trigger_enable_disable(file, 0);
475 if (data->ops->free)
476 data->ops->free(data->ops, data);
477 }
478 }
479}
480
481/**
482 * update_cond_flag - Set or reset the TRIGGER_COND bit
483 * @file: The ftrace_event_file associated with the event
484 *
485 * If an event has triggers and any of those triggers has a filter or
486 * a post_trigger, trigger invocation needs to be deferred until after
487 * the current event has logged its data, and the event should have
488 * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
489 * cleared.
490 */
491static void update_cond_flag(struct ftrace_event_file *file)
492{
493 struct event_trigger_data *data;
494 bool set_cond = false;
495
496 list_for_each_entry_rcu(data, &file->triggers, list) {
497 if (data->filter || data->cmd_ops->post_trigger) {
498 set_cond = true;
499 break;
500 }
501 }
502
503 if (set_cond)
504 set_bit(FTRACE_EVENT_FL_TRIGGER_COND_BIT, &file->flags);
505 else
506 clear_bit(FTRACE_EVENT_FL_TRIGGER_COND_BIT, &file->flags);
507}
508
509/**
510 * register_trigger - Generic event_command @reg implementation
511 * @glob: The raw string used to register the trigger
512 * @ops: The trigger ops associated with the trigger
513 * @data: Trigger-specific data to associate with the trigger
514 * @file: The ftrace_event_file associated with the event
515 *
516 * Common implementation for event trigger registration.
517 *
518 * Usually used directly as the @reg method in event command
519 * implementations.
520 *
521 * Return: 0 on success, errno otherwise
522 */
523static int register_trigger(char *glob, struct event_trigger_ops *ops,
524 struct event_trigger_data *data,
525 struct ftrace_event_file *file)
526{
527 struct event_trigger_data *test;
528 int ret = 0;
529
530 list_for_each_entry_rcu(test, &file->triggers, list) {
531 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
532 ret = -EEXIST;
533 goto out;
534 }
535 }
536
537 if (data->ops->init) {
538 ret = data->ops->init(data->ops, data);
539 if (ret < 0)
540 goto out;
541 }
542
543 list_add_rcu(&data->list, &file->triggers);
544 ret++;
545
546 if (trace_event_trigger_enable_disable(file, 1) < 0) {
547 list_del_rcu(&data->list);
548 ret--;
549 }
550 update_cond_flag(file);
551out:
552 return ret;
553}
554
555/**
556 * unregister_trigger - Generic event_command @unreg implementation
557 * @glob: The raw string used to register the trigger
558 * @ops: The trigger ops associated with the trigger
559 * @test: Trigger-specific data used to find the trigger to remove
560 * @file: The ftrace_event_file associated with the event
561 *
562 * Common implementation for event trigger unregistration.
563 *
564 * Usually used directly as the @unreg method in event command
565 * implementations.
566 */
567static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
568 struct event_trigger_data *test,
569 struct ftrace_event_file *file)
570{
571 struct event_trigger_data *data;
572 bool unregistered = false;
573
574 list_for_each_entry_rcu(data, &file->triggers, list) {
575 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
576 unregistered = true;
577 list_del_rcu(&data->list);
578 update_cond_flag(file);
579 trace_event_trigger_enable_disable(file, 0);
580 break;
581 }
582 }
583
584 if (unregistered && data->ops->free)
585 data->ops->free(data->ops, data);
586}
587
588/**
589 * event_trigger_callback - Generic event_command @func implementation
590 * @cmd_ops: The command ops, used for trigger registration
591 * @file: The ftrace_event_file associated with the event
592 * @glob: The raw string used to register the trigger
593 * @cmd: The cmd portion of the string used to register the trigger
594 * @param: The params portion of the string used to register the trigger
595 *
596 * Common implementation for event command parsing and trigger
597 * instantiation.
598 *
599 * Usually used directly as the @func method in event command
600 * implementations.
601 *
602 * Return: 0 on success, errno otherwise
603 */
604static int
605event_trigger_callback(struct event_command *cmd_ops,
606 struct ftrace_event_file *file,
607 char *glob, char *cmd, char *param)
608{
609 struct event_trigger_data *trigger_data;
610 struct event_trigger_ops *trigger_ops;
611 char *trigger = NULL;
612 char *number;
613 int ret;
614
615 /* separate the trigger from the filter (t:n [if filter]) */
616 if (param && isdigit(param[0]))
617 trigger = strsep(¶m, " \t");
618
619 trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
620
621 ret = -ENOMEM;
622 trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
623 if (!trigger_data)
624 goto out;
625
626 trigger_data->count = -1;
627 trigger_data->ops = trigger_ops;
628 trigger_data->cmd_ops = cmd_ops;
629 INIT_LIST_HEAD(&trigger_data->list);
630
631 if (glob[0] == '!') {
632 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
633 kfree(trigger_data);
634 ret = 0;
635 goto out;
636 }
637
638 if (trigger) {
639 number = strsep(&trigger, ":");
640
641 ret = -EINVAL;
642 if (!strlen(number))
643 goto out_free;
644
645 /*
646 * We use the callback data field (which is a pointer)
647 * as our counter.
648 */
649 ret = kstrtoul(number, 0, &trigger_data->count);
650 if (ret)
651 goto out_free;
652 }
653
654 if (!param) /* if param is non-empty, it's supposed to be a filter */
655 goto out_reg;
656
657 if (!cmd_ops->set_filter)
658 goto out_reg;
659
660 ret = cmd_ops->set_filter(param, trigger_data, file);
661 if (ret < 0)
662 goto out_free;
663
664 out_reg:
665 ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
666 /*
667 * The above returns on success the # of functions enabled,
668 * but if it didn't find any functions it returns zero.
669 * Consider no functions a failure too.
670 */
671 if (!ret) {
672 ret = -ENOENT;
673 goto out_free;
674 } else if (ret < 0)
675 goto out_free;
676 ret = 0;
677 out:
678 return ret;
679
680 out_free:
681 if (cmd_ops->set_filter)
682 cmd_ops->set_filter(NULL, trigger_data, NULL);
683 kfree(trigger_data);
684 goto out;
685}
686
687/**
688 * set_trigger_filter - Generic event_command @set_filter implementation
689 * @filter_str: The filter string for the trigger, NULL to remove filter
690 * @trigger_data: Trigger-specific data
691 * @file: The ftrace_event_file associated with the event
692 *
693 * Common implementation for event command filter parsing and filter
694 * instantiation.
695 *
696 * Usually used directly as the @set_filter method in event command
697 * implementations.
698 *
699 * Also used to remove a filter (if filter_str = NULL).
700 *
701 * Return: 0 on success, errno otherwise
702 */
703static int set_trigger_filter(char *filter_str,
704 struct event_trigger_data *trigger_data,
705 struct ftrace_event_file *file)
706{
707 struct event_trigger_data *data = trigger_data;
708 struct event_filter *filter = NULL, *tmp;
709 int ret = -EINVAL;
710 char *s;
711
712 if (!filter_str) /* clear the current filter */
713 goto assign;
714
715 s = strsep(&filter_str, " \t");
716
717 if (!strlen(s) || strcmp(s, "if") != 0)
718 goto out;
719
720 if (!filter_str)
721 goto out;
722
723 /* The filter is for the 'trigger' event, not the triggered event */
724 ret = create_event_filter(file->event_call, filter_str, false, &filter);
725 if (ret)
726 goto out;
727 assign:
728 tmp = rcu_access_pointer(data->filter);
729
730 rcu_assign_pointer(data->filter, filter);
731
732 if (tmp) {
733 /* Make sure the call is done with the filter */
734 synchronize_sched();
735 free_event_filter(tmp);
736 }
737
738 kfree(data->filter_str);
739 data->filter_str = NULL;
740
741 if (filter_str) {
742 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
743 if (!data->filter_str) {
744 free_event_filter(rcu_access_pointer(data->filter));
745 data->filter = NULL;
746 ret = -ENOMEM;
747 }
748 }
749 out:
750 return ret;
751}
752
753static void
754traceon_trigger(struct event_trigger_data *data)
755{
756 if (tracing_is_on())
757 return;
758
759 tracing_on();
760}
761
762static void
763traceon_count_trigger(struct event_trigger_data *data)
764{
765 if (tracing_is_on())
766 return;
767
768 if (!data->count)
769 return;
770
771 if (data->count != -1)
772 (data->count)--;
773
774 tracing_on();
775}
776
777static void
778traceoff_trigger(struct event_trigger_data *data)
779{
780 if (!tracing_is_on())
781 return;
782
783 tracing_off();
784}
785
786static void
787traceoff_count_trigger(struct event_trigger_data *data)
788{
789 if (!tracing_is_on())
790 return;
791
792 if (!data->count)
793 return;
794
795 if (data->count != -1)
796 (data->count)--;
797
798 tracing_off();
799}
800
801static int
802traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
803 struct event_trigger_data *data)
804{
805 return event_trigger_print("traceon", m, (void *)data->count,
806 data->filter_str);
807}
808
809static int
810traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
811 struct event_trigger_data *data)
812{
813 return event_trigger_print("traceoff", m, (void *)data->count,
814 data->filter_str);
815}
816
817static struct event_trigger_ops traceon_trigger_ops = {
818 .func = traceon_trigger,
819 .print = traceon_trigger_print,
820 .init = event_trigger_init,
821 .free = event_trigger_free,
822};
823
824static struct event_trigger_ops traceon_count_trigger_ops = {
825 .func = traceon_count_trigger,
826 .print = traceon_trigger_print,
827 .init = event_trigger_init,
828 .free = event_trigger_free,
829};
830
831static struct event_trigger_ops traceoff_trigger_ops = {
832 .func = traceoff_trigger,
833 .print = traceoff_trigger_print,
834 .init = event_trigger_init,
835 .free = event_trigger_free,
836};
837
838static struct event_trigger_ops traceoff_count_trigger_ops = {
839 .func = traceoff_count_trigger,
840 .print = traceoff_trigger_print,
841 .init = event_trigger_init,
842 .free = event_trigger_free,
843};
844
845static struct event_trigger_ops *
846onoff_get_trigger_ops(char *cmd, char *param)
847{
848 struct event_trigger_ops *ops;
849
850 /* we register both traceon and traceoff to this callback */
851 if (strcmp(cmd, "traceon") == 0)
852 ops = param ? &traceon_count_trigger_ops :
853 &traceon_trigger_ops;
854 else
855 ops = param ? &traceoff_count_trigger_ops :
856 &traceoff_trigger_ops;
857
858 return ops;
859}
860
861static struct event_command trigger_traceon_cmd = {
862 .name = "traceon",
863 .trigger_type = ETT_TRACE_ONOFF,
864 .func = event_trigger_callback,
865 .reg = register_trigger,
866 .unreg = unregister_trigger,
867 .get_trigger_ops = onoff_get_trigger_ops,
868 .set_filter = set_trigger_filter,
869};
870
871static struct event_command trigger_traceoff_cmd = {
872 .name = "traceoff",
873 .trigger_type = ETT_TRACE_ONOFF,
874 .func = event_trigger_callback,
875 .reg = register_trigger,
876 .unreg = unregister_trigger,
877 .get_trigger_ops = onoff_get_trigger_ops,
878 .set_filter = set_trigger_filter,
879};
880
881#ifdef CONFIG_TRACER_SNAPSHOT
882static void
883snapshot_trigger(struct event_trigger_data *data)
884{
885 tracing_snapshot();
886}
887
888static void
889snapshot_count_trigger(struct event_trigger_data *data)
890{
891 if (!data->count)
892 return;
893
894 if (data->count != -1)
895 (data->count)--;
896
897 snapshot_trigger(data);
898}
899
900static int
901register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
902 struct event_trigger_data *data,
903 struct ftrace_event_file *file)
904{
905 int ret = register_trigger(glob, ops, data, file);
906
907 if (ret > 0 && tracing_alloc_snapshot() != 0) {
908 unregister_trigger(glob, ops, data, file);
909 ret = 0;
910 }
911
912 return ret;
913}
914
915static int
916snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
917 struct event_trigger_data *data)
918{
919 return event_trigger_print("snapshot", m, (void *)data->count,
920 data->filter_str);
921}
922
923static struct event_trigger_ops snapshot_trigger_ops = {
924 .func = snapshot_trigger,
925 .print = snapshot_trigger_print,
926 .init = event_trigger_init,
927 .free = event_trigger_free,
928};
929
930static struct event_trigger_ops snapshot_count_trigger_ops = {
931 .func = snapshot_count_trigger,
932 .print = snapshot_trigger_print,
933 .init = event_trigger_init,
934 .free = event_trigger_free,
935};
936
937static struct event_trigger_ops *
938snapshot_get_trigger_ops(char *cmd, char *param)
939{
940 return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
941}
942
943static struct event_command trigger_snapshot_cmd = {
944 .name = "snapshot",
945 .trigger_type = ETT_SNAPSHOT,
946 .func = event_trigger_callback,
947 .reg = register_snapshot_trigger,
948 .unreg = unregister_trigger,
949 .get_trigger_ops = snapshot_get_trigger_ops,
950 .set_filter = set_trigger_filter,
951};
952
953static __init int register_trigger_snapshot_cmd(void)
954{
955 int ret;
956
957 ret = register_event_command(&trigger_snapshot_cmd);
958 WARN_ON(ret < 0);
959
960 return ret;
961}
962#else
963static __init int register_trigger_snapshot_cmd(void) { return 0; }
964#endif /* CONFIG_TRACER_SNAPSHOT */
965
966#ifdef CONFIG_STACKTRACE
967/*
968 * Skip 3:
969 * stacktrace_trigger()
970 * event_triggers_post_call()
971 * ftrace_raw_event_xxx()
972 */
973#define STACK_SKIP 3
974
975static void
976stacktrace_trigger(struct event_trigger_data *data)
977{
978 trace_dump_stack(STACK_SKIP);
979}
980
981static void
982stacktrace_count_trigger(struct event_trigger_data *data)
983{
984 if (!data->count)
985 return;
986
987 if (data->count != -1)
988 (data->count)--;
989
990 stacktrace_trigger(data);
991}
992
993static int
994stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
995 struct event_trigger_data *data)
996{
997 return event_trigger_print("stacktrace", m, (void *)data->count,
998 data->filter_str);
999}
1000
1001static struct event_trigger_ops stacktrace_trigger_ops = {
1002 .func = stacktrace_trigger,
1003 .print = stacktrace_trigger_print,
1004 .init = event_trigger_init,
1005 .free = event_trigger_free,
1006};
1007
1008static struct event_trigger_ops stacktrace_count_trigger_ops = {
1009 .func = stacktrace_count_trigger,
1010 .print = stacktrace_trigger_print,
1011 .init = event_trigger_init,
1012 .free = event_trigger_free,
1013};
1014
1015static struct event_trigger_ops *
1016stacktrace_get_trigger_ops(char *cmd, char *param)
1017{
1018 return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1019}
1020
1021static struct event_command trigger_stacktrace_cmd = {
1022 .name = "stacktrace",
1023 .trigger_type = ETT_STACKTRACE,
1024 .post_trigger = true,
1025 .func = event_trigger_callback,
1026 .reg = register_trigger,
1027 .unreg = unregister_trigger,
1028 .get_trigger_ops = stacktrace_get_trigger_ops,
1029 .set_filter = set_trigger_filter,
1030};
1031
1032static __init int register_trigger_stacktrace_cmd(void)
1033{
1034 int ret;
1035
1036 ret = register_event_command(&trigger_stacktrace_cmd);
1037 WARN_ON(ret < 0);
1038
1039 return ret;
1040}
1041#else
1042static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1043#endif /* CONFIG_STACKTRACE */
1044
1045static __init void unregister_trigger_traceon_traceoff_cmds(void)
1046{
1047 unregister_event_command(&trigger_traceon_cmd);
1048 unregister_event_command(&trigger_traceoff_cmd);
1049}
1050
1051/* Avoid typos */
1052#define ENABLE_EVENT_STR "enable_event"
1053#define DISABLE_EVENT_STR "disable_event"
1054
1055struct enable_trigger_data {
1056 struct ftrace_event_file *file;
1057 bool enable;
1058};
1059
1060static void
1061event_enable_trigger(struct event_trigger_data *data)
1062{
1063 struct enable_trigger_data *enable_data = data->private_data;
1064
1065 if (enable_data->enable)
1066 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1067 else
1068 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1069}
1070
1071static void
1072event_enable_count_trigger(struct event_trigger_data *data)
1073{
1074 struct enable_trigger_data *enable_data = data->private_data;
1075
1076 if (!data->count)
1077 return;
1078
1079 /* Skip if the event is in a state we want to switch to */
1080 if (enable_data->enable == !(enable_data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
1081 return;
1082
1083 if (data->count != -1)
1084 (data->count)--;
1085
1086 event_enable_trigger(data);
1087}
1088
1089static int
1090event_enable_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1091 struct event_trigger_data *data)
1092{
1093 struct enable_trigger_data *enable_data = data->private_data;
1094
1095 seq_printf(m, "%s:%s:%s",
1096 enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
1097 enable_data->file->event_call->class->system,
1098 ftrace_event_name(enable_data->file->event_call));
1099
1100 if (data->count == -1)
1101 seq_puts(m, ":unlimited");
1102 else
1103 seq_printf(m, ":count=%ld", data->count);
1104
1105 if (data->filter_str)
1106 seq_printf(m, " if %s\n", data->filter_str);
1107 else
1108 seq_puts(m, "\n");
1109
1110 return 0;
1111}
1112
1113static void
1114event_enable_trigger_free(struct event_trigger_ops *ops,
1115 struct event_trigger_data *data)
1116{
1117 struct enable_trigger_data *enable_data = data->private_data;
1118
1119 if (WARN_ON_ONCE(data->ref <= 0))
1120 return;
1121
1122 data->ref--;
1123 if (!data->ref) {
1124 /* Remove the SOFT_MODE flag */
1125 trace_event_enable_disable(enable_data->file, 0, 1);
1126 module_put(enable_data->file->event_call->mod);
1127 trigger_data_free(data);
1128 kfree(enable_data);
1129 }
1130}
1131
1132static struct event_trigger_ops event_enable_trigger_ops = {
1133 .func = event_enable_trigger,
1134 .print = event_enable_trigger_print,
1135 .init = event_trigger_init,
1136 .free = event_enable_trigger_free,
1137};
1138
1139static struct event_trigger_ops event_enable_count_trigger_ops = {
1140 .func = event_enable_count_trigger,
1141 .print = event_enable_trigger_print,
1142 .init = event_trigger_init,
1143 .free = event_enable_trigger_free,
1144};
1145
1146static struct event_trigger_ops event_disable_trigger_ops = {
1147 .func = event_enable_trigger,
1148 .print = event_enable_trigger_print,
1149 .init = event_trigger_init,
1150 .free = event_enable_trigger_free,
1151};
1152
1153static struct event_trigger_ops event_disable_count_trigger_ops = {
1154 .func = event_enable_count_trigger,
1155 .print = event_enable_trigger_print,
1156 .init = event_trigger_init,
1157 .free = event_enable_trigger_free,
1158};
1159
1160static int
1161event_enable_trigger_func(struct event_command *cmd_ops,
1162 struct ftrace_event_file *file,
1163 char *glob, char *cmd, char *param)
1164{
1165 struct ftrace_event_file *event_enable_file;
1166 struct enable_trigger_data *enable_data;
1167 struct event_trigger_data *trigger_data;
1168 struct event_trigger_ops *trigger_ops;
1169 struct trace_array *tr = file->tr;
1170 const char *system;
1171 const char *event;
1172 char *trigger;
1173 char *number;
1174 bool enable;
1175 int ret;
1176
1177 if (!param)
1178 return -EINVAL;
1179
1180 /* separate the trigger from the filter (s:e:n [if filter]) */
1181 trigger = strsep(¶m, " \t");
1182 if (!trigger)
1183 return -EINVAL;
1184
1185 system = strsep(&trigger, ":");
1186 if (!trigger)
1187 return -EINVAL;
1188
1189 event = strsep(&trigger, ":");
1190
1191 ret = -EINVAL;
1192 event_enable_file = find_event_file(tr, system, event);
1193 if (!event_enable_file)
1194 goto out;
1195
1196 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1197
1198 trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1199
1200 ret = -ENOMEM;
1201 trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1202 if (!trigger_data)
1203 goto out;
1204
1205 enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1206 if (!enable_data) {
1207 kfree(trigger_data);
1208 goto out;
1209 }
1210
1211 trigger_data->count = -1;
1212 trigger_data->ops = trigger_ops;
1213 trigger_data->cmd_ops = cmd_ops;
1214 INIT_LIST_HEAD(&trigger_data->list);
1215 RCU_INIT_POINTER(trigger_data->filter, NULL);
1216
1217 enable_data->enable = enable;
1218 enable_data->file = event_enable_file;
1219 trigger_data->private_data = enable_data;
1220
1221 if (glob[0] == '!') {
1222 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1223 kfree(trigger_data);
1224 kfree(enable_data);
1225 ret = 0;
1226 goto out;
1227 }
1228
1229 if (trigger) {
1230 number = strsep(&trigger, ":");
1231
1232 ret = -EINVAL;
1233 if (!strlen(number))
1234 goto out_free;
1235
1236 /*
1237 * We use the callback data field (which is a pointer)
1238 * as our counter.
1239 */
1240 ret = kstrtoul(number, 0, &trigger_data->count);
1241 if (ret)
1242 goto out_free;
1243 }
1244
1245 if (!param) /* if param is non-empty, it's supposed to be a filter */
1246 goto out_reg;
1247
1248 if (!cmd_ops->set_filter)
1249 goto out_reg;
1250
1251 ret = cmd_ops->set_filter(param, trigger_data, file);
1252 if (ret < 0)
1253 goto out_free;
1254
1255 out_reg:
1256 /* Don't let event modules unload while probe registered */
1257 ret = try_module_get(event_enable_file->event_call->mod);
1258 if (!ret) {
1259 ret = -EBUSY;
1260 goto out_free;
1261 }
1262
1263 ret = trace_event_enable_disable(event_enable_file, 1, 1);
1264 if (ret < 0)
1265 goto out_put;
1266 ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1267 /*
1268 * The above returns on success the # of functions enabled,
1269 * but if it didn't find any functions it returns zero.
1270 * Consider no functions a failure too.
1271 */
1272 if (!ret) {
1273 ret = -ENOENT;
1274 goto out_disable;
1275 } else if (ret < 0)
1276 goto out_disable;
1277 /* Just return zero, not the number of enabled functions */
1278 ret = 0;
1279 out:
1280 return ret;
1281
1282 out_disable:
1283 trace_event_enable_disable(event_enable_file, 0, 1);
1284 out_put:
1285 module_put(event_enable_file->event_call->mod);
1286 out_free:
1287 if (cmd_ops->set_filter)
1288 cmd_ops->set_filter(NULL, trigger_data, NULL);
1289 kfree(trigger_data);
1290 kfree(enable_data);
1291 goto out;
1292}
1293
1294static int event_enable_register_trigger(char *glob,
1295 struct event_trigger_ops *ops,
1296 struct event_trigger_data *data,
1297 struct ftrace_event_file *file)
1298{
1299 struct enable_trigger_data *enable_data = data->private_data;
1300 struct enable_trigger_data *test_enable_data;
1301 struct event_trigger_data *test;
1302 int ret = 0;
1303
1304 list_for_each_entry_rcu(test, &file->triggers, list) {
1305 test_enable_data = test->private_data;
1306 if (test_enable_data &&
1307 (test_enable_data->file == enable_data->file)) {
1308 ret = -EEXIST;
1309 goto out;
1310 }
1311 }
1312
1313 if (data->ops->init) {
1314 ret = data->ops->init(data->ops, data);
1315 if (ret < 0)
1316 goto out;
1317 }
1318
1319 list_add_rcu(&data->list, &file->triggers);
1320 ret++;
1321
1322 if (trace_event_trigger_enable_disable(file, 1) < 0) {
1323 list_del_rcu(&data->list);
1324 ret--;
1325 }
1326 update_cond_flag(file);
1327out:
1328 return ret;
1329}
1330
1331static void event_enable_unregister_trigger(char *glob,
1332 struct event_trigger_ops *ops,
1333 struct event_trigger_data *test,
1334 struct ftrace_event_file *file)
1335{
1336 struct enable_trigger_data *test_enable_data = test->private_data;
1337 struct enable_trigger_data *enable_data;
1338 struct event_trigger_data *data;
1339 bool unregistered = false;
1340
1341 list_for_each_entry_rcu(data, &file->triggers, list) {
1342 enable_data = data->private_data;
1343 if (enable_data &&
1344 (enable_data->file == test_enable_data->file)) {
1345 unregistered = true;
1346 list_del_rcu(&data->list);
1347 update_cond_flag(file);
1348 trace_event_trigger_enable_disable(file, 0);
1349 break;
1350 }
1351 }
1352
1353 if (unregistered && data->ops->free)
1354 data->ops->free(data->ops, data);
1355}
1356
1357static struct event_trigger_ops *
1358event_enable_get_trigger_ops(char *cmd, char *param)
1359{
1360 struct event_trigger_ops *ops;
1361 bool enable;
1362
1363 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1364
1365 if (enable)
1366 ops = param ? &event_enable_count_trigger_ops :
1367 &event_enable_trigger_ops;
1368 else
1369 ops = param ? &event_disable_count_trigger_ops :
1370 &event_disable_trigger_ops;
1371
1372 return ops;
1373}
1374
1375static struct event_command trigger_enable_cmd = {
1376 .name = ENABLE_EVENT_STR,
1377 .trigger_type = ETT_EVENT_ENABLE,
1378 .func = event_enable_trigger_func,
1379 .reg = event_enable_register_trigger,
1380 .unreg = event_enable_unregister_trigger,
1381 .get_trigger_ops = event_enable_get_trigger_ops,
1382 .set_filter = set_trigger_filter,
1383};
1384
1385static struct event_command trigger_disable_cmd = {
1386 .name = DISABLE_EVENT_STR,
1387 .trigger_type = ETT_EVENT_ENABLE,
1388 .func = event_enable_trigger_func,
1389 .reg = event_enable_register_trigger,
1390 .unreg = event_enable_unregister_trigger,
1391 .get_trigger_ops = event_enable_get_trigger_ops,
1392 .set_filter = set_trigger_filter,
1393};
1394
1395static __init void unregister_trigger_enable_disable_cmds(void)
1396{
1397 unregister_event_command(&trigger_enable_cmd);
1398 unregister_event_command(&trigger_disable_cmd);
1399}
1400
1401static __init int register_trigger_enable_disable_cmds(void)
1402{
1403 int ret;
1404
1405 ret = register_event_command(&trigger_enable_cmd);
1406 if (WARN_ON(ret < 0))
1407 return ret;
1408 ret = register_event_command(&trigger_disable_cmd);
1409 if (WARN_ON(ret < 0))
1410 unregister_trigger_enable_disable_cmds();
1411
1412 return ret;
1413}
1414
1415static __init int register_trigger_traceon_traceoff_cmds(void)
1416{
1417 int ret;
1418
1419 ret = register_event_command(&trigger_traceon_cmd);
1420 if (WARN_ON(ret < 0))
1421 return ret;
1422 ret = register_event_command(&trigger_traceoff_cmd);
1423 if (WARN_ON(ret < 0))
1424 unregister_trigger_traceon_traceoff_cmds();
1425
1426 return ret;
1427}
1428
1429__init int register_trigger_cmds(void)
1430{
1431 register_trigger_traceon_traceoff_cmds();
1432 register_trigger_snapshot_cmd();
1433 register_trigger_stacktrace_cmd();
1434 register_trigger_enable_disable_cmds();
1435
1436 return 0;
1437}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * trace_events_trigger - trace event triggers
4 *
5 * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
6 */
7
8#include <linux/security.h>
9#include <linux/module.h>
10#include <linux/ctype.h>
11#include <linux/mutex.h>
12#include <linux/slab.h>
13#include <linux/rculist.h>
14
15#include "trace.h"
16
17static LIST_HEAD(trigger_commands);
18static DEFINE_MUTEX(trigger_cmd_mutex);
19
20void trigger_data_free(struct event_trigger_data *data)
21{
22 if (data->cmd_ops->set_filter)
23 data->cmd_ops->set_filter(NULL, data, NULL);
24
25 /* make sure current triggers exit before free */
26 tracepoint_synchronize_unregister();
27
28 kfree(data);
29}
30
31/**
32 * event_triggers_call - Call triggers associated with a trace event
33 * @file: The trace_event_file associated with the event
34 * @rec: The trace entry for the event, NULL for unconditional invocation
35 *
36 * For each trigger associated with an event, invoke the trigger
37 * function registered with the associated trigger command. If rec is
38 * non-NULL, it means that the trigger requires further processing and
39 * shouldn't be unconditionally invoked. If rec is non-NULL and the
40 * trigger has a filter associated with it, rec will checked against
41 * the filter and if the record matches the trigger will be invoked.
42 * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
43 * in any case until the current event is written, the trigger
44 * function isn't invoked but the bit associated with the deferred
45 * trigger is set in the return value.
46 *
47 * Returns an enum event_trigger_type value containing a set bit for
48 * any trigger that should be deferred, ETT_NONE if nothing to defer.
49 *
50 * Called from tracepoint handlers (with rcu_read_lock_sched() held).
51 *
52 * Return: an enum event_trigger_type value containing a set bit for
53 * any trigger that should be deferred, ETT_NONE if nothing to defer.
54 */
55enum event_trigger_type
56event_triggers_call(struct trace_event_file *file, void *rec,
57 struct ring_buffer_event *event)
58{
59 struct event_trigger_data *data;
60 enum event_trigger_type tt = ETT_NONE;
61 struct event_filter *filter;
62
63 if (list_empty(&file->triggers))
64 return tt;
65
66 list_for_each_entry_rcu(data, &file->triggers, list) {
67 if (data->paused)
68 continue;
69 if (!rec) {
70 data->ops->func(data, rec, event);
71 continue;
72 }
73 filter = rcu_dereference_sched(data->filter);
74 if (filter && !filter_match_preds(filter, rec))
75 continue;
76 if (event_command_post_trigger(data->cmd_ops)) {
77 tt |= data->cmd_ops->trigger_type;
78 continue;
79 }
80 data->ops->func(data, rec, event);
81 }
82 return tt;
83}
84EXPORT_SYMBOL_GPL(event_triggers_call);
85
86/**
87 * event_triggers_post_call - Call 'post_triggers' for a trace event
88 * @file: The trace_event_file associated with the event
89 * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
90 *
91 * For each trigger associated with an event, invoke the trigger
92 * function registered with the associated trigger command, if the
93 * corresponding bit is set in the tt enum passed into this function.
94 * See @event_triggers_call for details on how those bits are set.
95 *
96 * Called from tracepoint handlers (with rcu_read_lock_sched() held).
97 */
98void
99event_triggers_post_call(struct trace_event_file *file,
100 enum event_trigger_type tt)
101{
102 struct event_trigger_data *data;
103
104 list_for_each_entry_rcu(data, &file->triggers, list) {
105 if (data->paused)
106 continue;
107 if (data->cmd_ops->trigger_type & tt)
108 data->ops->func(data, NULL, NULL);
109 }
110}
111EXPORT_SYMBOL_GPL(event_triggers_post_call);
112
113#define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
114
115static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
116{
117 struct trace_event_file *event_file = event_file_data(m->private);
118
119 if (t == SHOW_AVAILABLE_TRIGGERS) {
120 (*pos)++;
121 return NULL;
122 }
123 return seq_list_next(t, &event_file->triggers, pos);
124}
125
126static void *trigger_start(struct seq_file *m, loff_t *pos)
127{
128 struct trace_event_file *event_file;
129
130 /* ->stop() is called even if ->start() fails */
131 mutex_lock(&event_mutex);
132 event_file = event_file_data(m->private);
133 if (unlikely(!event_file))
134 return ERR_PTR(-ENODEV);
135
136 if (list_empty(&event_file->triggers))
137 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
138
139 return seq_list_start(&event_file->triggers, *pos);
140}
141
142static void trigger_stop(struct seq_file *m, void *t)
143{
144 mutex_unlock(&event_mutex);
145}
146
147static int trigger_show(struct seq_file *m, void *v)
148{
149 struct event_trigger_data *data;
150 struct event_command *p;
151
152 if (v == SHOW_AVAILABLE_TRIGGERS) {
153 seq_puts(m, "# Available triggers:\n");
154 seq_putc(m, '#');
155 mutex_lock(&trigger_cmd_mutex);
156 list_for_each_entry_reverse(p, &trigger_commands, list)
157 seq_printf(m, " %s", p->name);
158 seq_putc(m, '\n');
159 mutex_unlock(&trigger_cmd_mutex);
160 return 0;
161 }
162
163 data = list_entry(v, struct event_trigger_data, list);
164 data->ops->print(m, data->ops, data);
165
166 return 0;
167}
168
169static const struct seq_operations event_triggers_seq_ops = {
170 .start = trigger_start,
171 .next = trigger_next,
172 .stop = trigger_stop,
173 .show = trigger_show,
174};
175
176static int event_trigger_regex_open(struct inode *inode, struct file *file)
177{
178 int ret;
179
180 ret = security_locked_down(LOCKDOWN_TRACEFS);
181 if (ret)
182 return ret;
183
184 mutex_lock(&event_mutex);
185
186 if (unlikely(!event_file_data(file))) {
187 mutex_unlock(&event_mutex);
188 return -ENODEV;
189 }
190
191 if ((file->f_mode & FMODE_WRITE) &&
192 (file->f_flags & O_TRUNC)) {
193 struct trace_event_file *event_file;
194 struct event_command *p;
195
196 event_file = event_file_data(file);
197
198 list_for_each_entry(p, &trigger_commands, list) {
199 if (p->unreg_all)
200 p->unreg_all(event_file);
201 }
202 }
203
204 if (file->f_mode & FMODE_READ) {
205 ret = seq_open(file, &event_triggers_seq_ops);
206 if (!ret) {
207 struct seq_file *m = file->private_data;
208 m->private = file;
209 }
210 }
211
212 mutex_unlock(&event_mutex);
213
214 return ret;
215}
216
217int trigger_process_regex(struct trace_event_file *file, char *buff)
218{
219 char *command, *next;
220 struct event_command *p;
221 int ret = -EINVAL;
222
223 next = buff = skip_spaces(buff);
224 command = strsep(&next, ": \t");
225 if (next) {
226 next = skip_spaces(next);
227 if (!*next)
228 next = NULL;
229 }
230 command = (command[0] != '!') ? command : command + 1;
231
232 mutex_lock(&trigger_cmd_mutex);
233 list_for_each_entry(p, &trigger_commands, list) {
234 if (strcmp(p->name, command) == 0) {
235 ret = p->func(p, file, buff, command, next);
236 goto out_unlock;
237 }
238 }
239 out_unlock:
240 mutex_unlock(&trigger_cmd_mutex);
241
242 return ret;
243}
244
245static ssize_t event_trigger_regex_write(struct file *file,
246 const char __user *ubuf,
247 size_t cnt, loff_t *ppos)
248{
249 struct trace_event_file *event_file;
250 ssize_t ret;
251 char *buf;
252
253 if (!cnt)
254 return 0;
255
256 if (cnt >= PAGE_SIZE)
257 return -EINVAL;
258
259 buf = memdup_user_nul(ubuf, cnt);
260 if (IS_ERR(buf))
261 return PTR_ERR(buf);
262
263 strim(buf);
264
265 mutex_lock(&event_mutex);
266 event_file = event_file_data(file);
267 if (unlikely(!event_file)) {
268 mutex_unlock(&event_mutex);
269 kfree(buf);
270 return -ENODEV;
271 }
272 ret = trigger_process_regex(event_file, buf);
273 mutex_unlock(&event_mutex);
274
275 kfree(buf);
276 if (ret < 0)
277 goto out;
278
279 *ppos += cnt;
280 ret = cnt;
281 out:
282 return ret;
283}
284
285static int event_trigger_regex_release(struct inode *inode, struct file *file)
286{
287 mutex_lock(&event_mutex);
288
289 if (file->f_mode & FMODE_READ)
290 seq_release(inode, file);
291
292 mutex_unlock(&event_mutex);
293
294 return 0;
295}
296
297static ssize_t
298event_trigger_write(struct file *filp, const char __user *ubuf,
299 size_t cnt, loff_t *ppos)
300{
301 return event_trigger_regex_write(filp, ubuf, cnt, ppos);
302}
303
304static int
305event_trigger_open(struct inode *inode, struct file *filp)
306{
307 /* Checks for tracefs lockdown */
308 return event_trigger_regex_open(inode, filp);
309}
310
311static int
312event_trigger_release(struct inode *inode, struct file *file)
313{
314 return event_trigger_regex_release(inode, file);
315}
316
317const struct file_operations event_trigger_fops = {
318 .open = event_trigger_open,
319 .read = seq_read,
320 .write = event_trigger_write,
321 .llseek = tracing_lseek,
322 .release = event_trigger_release,
323};
324
325/*
326 * Currently we only register event commands from __init, so mark this
327 * __init too.
328 */
329__init int register_event_command(struct event_command *cmd)
330{
331 struct event_command *p;
332 int ret = 0;
333
334 mutex_lock(&trigger_cmd_mutex);
335 list_for_each_entry(p, &trigger_commands, list) {
336 if (strcmp(cmd->name, p->name) == 0) {
337 ret = -EBUSY;
338 goto out_unlock;
339 }
340 }
341 list_add(&cmd->list, &trigger_commands);
342 out_unlock:
343 mutex_unlock(&trigger_cmd_mutex);
344
345 return ret;
346}
347
348/*
349 * Currently we only unregister event commands from __init, so mark
350 * this __init too.
351 */
352__init int unregister_event_command(struct event_command *cmd)
353{
354 struct event_command *p, *n;
355 int ret = -ENODEV;
356
357 mutex_lock(&trigger_cmd_mutex);
358 list_for_each_entry_safe(p, n, &trigger_commands, list) {
359 if (strcmp(cmd->name, p->name) == 0) {
360 ret = 0;
361 list_del_init(&p->list);
362 goto out_unlock;
363 }
364 }
365 out_unlock:
366 mutex_unlock(&trigger_cmd_mutex);
367
368 return ret;
369}
370
371/**
372 * event_trigger_print - Generic event_trigger_ops @print implementation
373 * @name: The name of the event trigger
374 * @m: The seq_file being printed to
375 * @data: Trigger-specific data
376 * @filter_str: filter_str to print, if present
377 *
378 * Common implementation for event triggers to print themselves.
379 *
380 * Usually wrapped by a function that simply sets the @name of the
381 * trigger command and then invokes this.
382 *
383 * Return: 0 on success, errno otherwise
384 */
385static int
386event_trigger_print(const char *name, struct seq_file *m,
387 void *data, char *filter_str)
388{
389 long count = (long)data;
390
391 seq_puts(m, name);
392
393 if (count == -1)
394 seq_puts(m, ":unlimited");
395 else
396 seq_printf(m, ":count=%ld", count);
397
398 if (filter_str)
399 seq_printf(m, " if %s\n", filter_str);
400 else
401 seq_putc(m, '\n');
402
403 return 0;
404}
405
406/**
407 * event_trigger_init - Generic event_trigger_ops @init implementation
408 * @ops: The trigger ops associated with the trigger
409 * @data: Trigger-specific data
410 *
411 * Common implementation of event trigger initialization.
412 *
413 * Usually used directly as the @init method in event trigger
414 * implementations.
415 *
416 * Return: 0 on success, errno otherwise
417 */
418int event_trigger_init(struct event_trigger_ops *ops,
419 struct event_trigger_data *data)
420{
421 data->ref++;
422 return 0;
423}
424
425/**
426 * event_trigger_free - Generic event_trigger_ops @free implementation
427 * @ops: The trigger ops associated with the trigger
428 * @data: Trigger-specific data
429 *
430 * Common implementation of event trigger de-initialization.
431 *
432 * Usually used directly as the @free method in event trigger
433 * implementations.
434 */
435static void
436event_trigger_free(struct event_trigger_ops *ops,
437 struct event_trigger_data *data)
438{
439 if (WARN_ON_ONCE(data->ref <= 0))
440 return;
441
442 data->ref--;
443 if (!data->ref)
444 trigger_data_free(data);
445}
446
447int trace_event_trigger_enable_disable(struct trace_event_file *file,
448 int trigger_enable)
449{
450 int ret = 0;
451
452 if (trigger_enable) {
453 if (atomic_inc_return(&file->tm_ref) > 1)
454 return ret;
455 set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
456 ret = trace_event_enable_disable(file, 1, 1);
457 } else {
458 if (atomic_dec_return(&file->tm_ref) > 0)
459 return ret;
460 clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
461 ret = trace_event_enable_disable(file, 0, 1);
462 }
463
464 return ret;
465}
466
467/**
468 * clear_event_triggers - Clear all triggers associated with a trace array
469 * @tr: The trace array to clear
470 *
471 * For each trigger, the triggering event has its tm_ref decremented
472 * via trace_event_trigger_enable_disable(), and any associated event
473 * (in the case of enable/disable_event triggers) will have its sm_ref
474 * decremented via free()->trace_event_enable_disable(). That
475 * combination effectively reverses the soft-mode/trigger state added
476 * by trigger registration.
477 *
478 * Must be called with event_mutex held.
479 */
480void
481clear_event_triggers(struct trace_array *tr)
482{
483 struct trace_event_file *file;
484
485 list_for_each_entry(file, &tr->events, list) {
486 struct event_trigger_data *data, *n;
487 list_for_each_entry_safe(data, n, &file->triggers, list) {
488 trace_event_trigger_enable_disable(file, 0);
489 list_del_rcu(&data->list);
490 if (data->ops->free)
491 data->ops->free(data->ops, data);
492 }
493 }
494}
495
496/**
497 * update_cond_flag - Set or reset the TRIGGER_COND bit
498 * @file: The trace_event_file associated with the event
499 *
500 * If an event has triggers and any of those triggers has a filter or
501 * a post_trigger, trigger invocation needs to be deferred until after
502 * the current event has logged its data, and the event should have
503 * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
504 * cleared.
505 */
506void update_cond_flag(struct trace_event_file *file)
507{
508 struct event_trigger_data *data;
509 bool set_cond = false;
510
511 lockdep_assert_held(&event_mutex);
512
513 list_for_each_entry(data, &file->triggers, list) {
514 if (data->filter || event_command_post_trigger(data->cmd_ops) ||
515 event_command_needs_rec(data->cmd_ops)) {
516 set_cond = true;
517 break;
518 }
519 }
520
521 if (set_cond)
522 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
523 else
524 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
525}
526
527/**
528 * register_trigger - Generic event_command @reg implementation
529 * @glob: The raw string used to register the trigger
530 * @ops: The trigger ops associated with the trigger
531 * @data: Trigger-specific data to associate with the trigger
532 * @file: The trace_event_file associated with the event
533 *
534 * Common implementation for event trigger registration.
535 *
536 * Usually used directly as the @reg method in event command
537 * implementations.
538 *
539 * Return: 0 on success, errno otherwise
540 */
541static int register_trigger(char *glob, struct event_trigger_ops *ops,
542 struct event_trigger_data *data,
543 struct trace_event_file *file)
544{
545 struct event_trigger_data *test;
546 int ret = 0;
547
548 lockdep_assert_held(&event_mutex);
549
550 list_for_each_entry(test, &file->triggers, list) {
551 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
552 ret = -EEXIST;
553 goto out;
554 }
555 }
556
557 if (data->ops->init) {
558 ret = data->ops->init(data->ops, data);
559 if (ret < 0)
560 goto out;
561 }
562
563 list_add_rcu(&data->list, &file->triggers);
564 ret++;
565
566 update_cond_flag(file);
567 if (trace_event_trigger_enable_disable(file, 1) < 0) {
568 list_del_rcu(&data->list);
569 update_cond_flag(file);
570 ret--;
571 }
572out:
573 return ret;
574}
575
576/**
577 * unregister_trigger - Generic event_command @unreg implementation
578 * @glob: The raw string used to register the trigger
579 * @ops: The trigger ops associated with the trigger
580 * @test: Trigger-specific data used to find the trigger to remove
581 * @file: The trace_event_file associated with the event
582 *
583 * Common implementation for event trigger unregistration.
584 *
585 * Usually used directly as the @unreg method in event command
586 * implementations.
587 */
588static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
589 struct event_trigger_data *test,
590 struct trace_event_file *file)
591{
592 struct event_trigger_data *data;
593 bool unregistered = false;
594
595 lockdep_assert_held(&event_mutex);
596
597 list_for_each_entry(data, &file->triggers, list) {
598 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
599 unregistered = true;
600 list_del_rcu(&data->list);
601 trace_event_trigger_enable_disable(file, 0);
602 update_cond_flag(file);
603 break;
604 }
605 }
606
607 if (unregistered && data->ops->free)
608 data->ops->free(data->ops, data);
609}
610
611/**
612 * event_trigger_callback - Generic event_command @func implementation
613 * @cmd_ops: The command ops, used for trigger registration
614 * @file: The trace_event_file associated with the event
615 * @glob: The raw string used to register the trigger
616 * @cmd: The cmd portion of the string used to register the trigger
617 * @param: The params portion of the string used to register the trigger
618 *
619 * Common implementation for event command parsing and trigger
620 * instantiation.
621 *
622 * Usually used directly as the @func method in event command
623 * implementations.
624 *
625 * Return: 0 on success, errno otherwise
626 */
627static int
628event_trigger_callback(struct event_command *cmd_ops,
629 struct trace_event_file *file,
630 char *glob, char *cmd, char *param)
631{
632 struct event_trigger_data *trigger_data;
633 struct event_trigger_ops *trigger_ops;
634 char *trigger = NULL;
635 char *number;
636 int ret;
637
638 /* separate the trigger from the filter (t:n [if filter]) */
639 if (param && isdigit(param[0])) {
640 trigger = strsep(¶m, " \t");
641 if (param) {
642 param = skip_spaces(param);
643 if (!*param)
644 param = NULL;
645 }
646 }
647
648 trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
649
650 ret = -ENOMEM;
651 trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
652 if (!trigger_data)
653 goto out;
654
655 trigger_data->count = -1;
656 trigger_data->ops = trigger_ops;
657 trigger_data->cmd_ops = cmd_ops;
658 trigger_data->private_data = file;
659 INIT_LIST_HEAD(&trigger_data->list);
660 INIT_LIST_HEAD(&trigger_data->named_list);
661
662 if (glob[0] == '!') {
663 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
664 kfree(trigger_data);
665 ret = 0;
666 goto out;
667 }
668
669 if (trigger) {
670 number = strsep(&trigger, ":");
671
672 ret = -EINVAL;
673 if (!strlen(number))
674 goto out_free;
675
676 /*
677 * We use the callback data field (which is a pointer)
678 * as our counter.
679 */
680 ret = kstrtoul(number, 0, &trigger_data->count);
681 if (ret)
682 goto out_free;
683 }
684
685 if (!param) /* if param is non-empty, it's supposed to be a filter */
686 goto out_reg;
687
688 if (!cmd_ops->set_filter)
689 goto out_reg;
690
691 ret = cmd_ops->set_filter(param, trigger_data, file);
692 if (ret < 0)
693 goto out_free;
694
695 out_reg:
696 /* Up the trigger_data count to make sure reg doesn't free it on failure */
697 event_trigger_init(trigger_ops, trigger_data);
698 ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
699 /*
700 * The above returns on success the # of functions enabled,
701 * but if it didn't find any functions it returns zero.
702 * Consider no functions a failure too.
703 */
704 if (!ret) {
705 cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
706 ret = -ENOENT;
707 } else if (ret > 0)
708 ret = 0;
709
710 /* Down the counter of trigger_data or free it if not used anymore */
711 event_trigger_free(trigger_ops, trigger_data);
712 out:
713 return ret;
714
715 out_free:
716 if (cmd_ops->set_filter)
717 cmd_ops->set_filter(NULL, trigger_data, NULL);
718 kfree(trigger_data);
719 goto out;
720}
721
722/**
723 * set_trigger_filter - Generic event_command @set_filter implementation
724 * @filter_str: The filter string for the trigger, NULL to remove filter
725 * @trigger_data: Trigger-specific data
726 * @file: The trace_event_file associated with the event
727 *
728 * Common implementation for event command filter parsing and filter
729 * instantiation.
730 *
731 * Usually used directly as the @set_filter method in event command
732 * implementations.
733 *
734 * Also used to remove a filter (if filter_str = NULL).
735 *
736 * Return: 0 on success, errno otherwise
737 */
738int set_trigger_filter(char *filter_str,
739 struct event_trigger_data *trigger_data,
740 struct trace_event_file *file)
741{
742 struct event_trigger_data *data = trigger_data;
743 struct event_filter *filter = NULL, *tmp;
744 int ret = -EINVAL;
745 char *s;
746
747 if (!filter_str) /* clear the current filter */
748 goto assign;
749
750 s = strsep(&filter_str, " \t");
751
752 if (!strlen(s) || strcmp(s, "if") != 0)
753 goto out;
754
755 if (!filter_str)
756 goto out;
757
758 /* The filter is for the 'trigger' event, not the triggered event */
759 ret = create_event_filter(file->tr, file->event_call,
760 filter_str, false, &filter);
761 /*
762 * If create_event_filter() fails, filter still needs to be freed.
763 * Which the calling code will do with data->filter.
764 */
765 assign:
766 tmp = rcu_access_pointer(data->filter);
767
768 rcu_assign_pointer(data->filter, filter);
769
770 if (tmp) {
771 /* Make sure the call is done with the filter */
772 tracepoint_synchronize_unregister();
773 free_event_filter(tmp);
774 }
775
776 kfree(data->filter_str);
777 data->filter_str = NULL;
778
779 if (filter_str) {
780 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
781 if (!data->filter_str) {
782 free_event_filter(rcu_access_pointer(data->filter));
783 data->filter = NULL;
784 ret = -ENOMEM;
785 }
786 }
787 out:
788 return ret;
789}
790
791static LIST_HEAD(named_triggers);
792
793/**
794 * find_named_trigger - Find the common named trigger associated with @name
795 * @name: The name of the set of named triggers to find the common data for
796 *
797 * Named triggers are sets of triggers that share a common set of
798 * trigger data. The first named trigger registered with a given name
799 * owns the common trigger data that the others subsequently
800 * registered with the same name will reference. This function
801 * returns the common trigger data associated with that first
802 * registered instance.
803 *
804 * Return: the common trigger data for the given named trigger on
805 * success, NULL otherwise.
806 */
807struct event_trigger_data *find_named_trigger(const char *name)
808{
809 struct event_trigger_data *data;
810
811 if (!name)
812 return NULL;
813
814 list_for_each_entry(data, &named_triggers, named_list) {
815 if (data->named_data)
816 continue;
817 if (strcmp(data->name, name) == 0)
818 return data;
819 }
820
821 return NULL;
822}
823
824/**
825 * is_named_trigger - determine if a given trigger is a named trigger
826 * @test: The trigger data to test
827 *
828 * Return: true if 'test' is a named trigger, false otherwise.
829 */
830bool is_named_trigger(struct event_trigger_data *test)
831{
832 struct event_trigger_data *data;
833
834 list_for_each_entry(data, &named_triggers, named_list) {
835 if (test == data)
836 return true;
837 }
838
839 return false;
840}
841
842/**
843 * save_named_trigger - save the trigger in the named trigger list
844 * @name: The name of the named trigger set
845 * @data: The trigger data to save
846 *
847 * Return: 0 if successful, negative error otherwise.
848 */
849int save_named_trigger(const char *name, struct event_trigger_data *data)
850{
851 data->name = kstrdup(name, GFP_KERNEL);
852 if (!data->name)
853 return -ENOMEM;
854
855 list_add(&data->named_list, &named_triggers);
856
857 return 0;
858}
859
860/**
861 * del_named_trigger - delete a trigger from the named trigger list
862 * @data: The trigger data to delete
863 */
864void del_named_trigger(struct event_trigger_data *data)
865{
866 kfree(data->name);
867 data->name = NULL;
868
869 list_del(&data->named_list);
870}
871
872static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
873{
874 struct event_trigger_data *test;
875
876 list_for_each_entry(test, &named_triggers, named_list) {
877 if (strcmp(test->name, data->name) == 0) {
878 if (pause) {
879 test->paused_tmp = test->paused;
880 test->paused = true;
881 } else {
882 test->paused = test->paused_tmp;
883 }
884 }
885 }
886}
887
888/**
889 * pause_named_trigger - Pause all named triggers with the same name
890 * @data: The trigger data of a named trigger to pause
891 *
892 * Pauses a named trigger along with all other triggers having the
893 * same name. Because named triggers share a common set of data,
894 * pausing only one is meaningless, so pausing one named trigger needs
895 * to pause all triggers with the same name.
896 */
897void pause_named_trigger(struct event_trigger_data *data)
898{
899 __pause_named_trigger(data, true);
900}
901
902/**
903 * unpause_named_trigger - Un-pause all named triggers with the same name
904 * @data: The trigger data of a named trigger to unpause
905 *
906 * Un-pauses a named trigger along with all other triggers having the
907 * same name. Because named triggers share a common set of data,
908 * unpausing only one is meaningless, so unpausing one named trigger
909 * needs to unpause all triggers with the same name.
910 */
911void unpause_named_trigger(struct event_trigger_data *data)
912{
913 __pause_named_trigger(data, false);
914}
915
916/**
917 * set_named_trigger_data - Associate common named trigger data
918 * @data: The trigger data of a named trigger to unpause
919 *
920 * Named triggers are sets of triggers that share a common set of
921 * trigger data. The first named trigger registered with a given name
922 * owns the common trigger data that the others subsequently
923 * registered with the same name will reference. This function
924 * associates the common trigger data from the first trigger with the
925 * given trigger.
926 */
927void set_named_trigger_data(struct event_trigger_data *data,
928 struct event_trigger_data *named_data)
929{
930 data->named_data = named_data;
931}
932
933struct event_trigger_data *
934get_named_trigger_data(struct event_trigger_data *data)
935{
936 return data->named_data;
937}
938
939static void
940traceon_trigger(struct event_trigger_data *data, void *rec,
941 struct ring_buffer_event *event)
942{
943 if (tracing_is_on())
944 return;
945
946 tracing_on();
947}
948
949static void
950traceon_count_trigger(struct event_trigger_data *data, void *rec,
951 struct ring_buffer_event *event)
952{
953 if (tracing_is_on())
954 return;
955
956 if (!data->count)
957 return;
958
959 if (data->count != -1)
960 (data->count)--;
961
962 tracing_on();
963}
964
965static void
966traceoff_trigger(struct event_trigger_data *data, void *rec,
967 struct ring_buffer_event *event)
968{
969 if (!tracing_is_on())
970 return;
971
972 tracing_off();
973}
974
975static void
976traceoff_count_trigger(struct event_trigger_data *data, void *rec,
977 struct ring_buffer_event *event)
978{
979 if (!tracing_is_on())
980 return;
981
982 if (!data->count)
983 return;
984
985 if (data->count != -1)
986 (data->count)--;
987
988 tracing_off();
989}
990
991static int
992traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
993 struct event_trigger_data *data)
994{
995 return event_trigger_print("traceon", m, (void *)data->count,
996 data->filter_str);
997}
998
999static int
1000traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1001 struct event_trigger_data *data)
1002{
1003 return event_trigger_print("traceoff", m, (void *)data->count,
1004 data->filter_str);
1005}
1006
1007static struct event_trigger_ops traceon_trigger_ops = {
1008 .func = traceon_trigger,
1009 .print = traceon_trigger_print,
1010 .init = event_trigger_init,
1011 .free = event_trigger_free,
1012};
1013
1014static struct event_trigger_ops traceon_count_trigger_ops = {
1015 .func = traceon_count_trigger,
1016 .print = traceon_trigger_print,
1017 .init = event_trigger_init,
1018 .free = event_trigger_free,
1019};
1020
1021static struct event_trigger_ops traceoff_trigger_ops = {
1022 .func = traceoff_trigger,
1023 .print = traceoff_trigger_print,
1024 .init = event_trigger_init,
1025 .free = event_trigger_free,
1026};
1027
1028static struct event_trigger_ops traceoff_count_trigger_ops = {
1029 .func = traceoff_count_trigger,
1030 .print = traceoff_trigger_print,
1031 .init = event_trigger_init,
1032 .free = event_trigger_free,
1033};
1034
1035static struct event_trigger_ops *
1036onoff_get_trigger_ops(char *cmd, char *param)
1037{
1038 struct event_trigger_ops *ops;
1039
1040 /* we register both traceon and traceoff to this callback */
1041 if (strcmp(cmd, "traceon") == 0)
1042 ops = param ? &traceon_count_trigger_ops :
1043 &traceon_trigger_ops;
1044 else
1045 ops = param ? &traceoff_count_trigger_ops :
1046 &traceoff_trigger_ops;
1047
1048 return ops;
1049}
1050
1051static struct event_command trigger_traceon_cmd = {
1052 .name = "traceon",
1053 .trigger_type = ETT_TRACE_ONOFF,
1054 .func = event_trigger_callback,
1055 .reg = register_trigger,
1056 .unreg = unregister_trigger,
1057 .get_trigger_ops = onoff_get_trigger_ops,
1058 .set_filter = set_trigger_filter,
1059};
1060
1061static struct event_command trigger_traceoff_cmd = {
1062 .name = "traceoff",
1063 .trigger_type = ETT_TRACE_ONOFF,
1064 .flags = EVENT_CMD_FL_POST_TRIGGER,
1065 .func = event_trigger_callback,
1066 .reg = register_trigger,
1067 .unreg = unregister_trigger,
1068 .get_trigger_ops = onoff_get_trigger_ops,
1069 .set_filter = set_trigger_filter,
1070};
1071
1072#ifdef CONFIG_TRACER_SNAPSHOT
1073static void
1074snapshot_trigger(struct event_trigger_data *data, void *rec,
1075 struct ring_buffer_event *event)
1076{
1077 struct trace_event_file *file = data->private_data;
1078
1079 if (file)
1080 tracing_snapshot_instance(file->tr);
1081 else
1082 tracing_snapshot();
1083}
1084
1085static void
1086snapshot_count_trigger(struct event_trigger_data *data, void *rec,
1087 struct ring_buffer_event *event)
1088{
1089 if (!data->count)
1090 return;
1091
1092 if (data->count != -1)
1093 (data->count)--;
1094
1095 snapshot_trigger(data, rec, event);
1096}
1097
1098static int
1099register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1100 struct event_trigger_data *data,
1101 struct trace_event_file *file)
1102{
1103 if (tracing_alloc_snapshot_instance(file->tr) != 0)
1104 return 0;
1105
1106 return register_trigger(glob, ops, data, file);
1107}
1108
1109static int
1110snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1111 struct event_trigger_data *data)
1112{
1113 return event_trigger_print("snapshot", m, (void *)data->count,
1114 data->filter_str);
1115}
1116
1117static struct event_trigger_ops snapshot_trigger_ops = {
1118 .func = snapshot_trigger,
1119 .print = snapshot_trigger_print,
1120 .init = event_trigger_init,
1121 .free = event_trigger_free,
1122};
1123
1124static struct event_trigger_ops snapshot_count_trigger_ops = {
1125 .func = snapshot_count_trigger,
1126 .print = snapshot_trigger_print,
1127 .init = event_trigger_init,
1128 .free = event_trigger_free,
1129};
1130
1131static struct event_trigger_ops *
1132snapshot_get_trigger_ops(char *cmd, char *param)
1133{
1134 return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1135}
1136
1137static struct event_command trigger_snapshot_cmd = {
1138 .name = "snapshot",
1139 .trigger_type = ETT_SNAPSHOT,
1140 .func = event_trigger_callback,
1141 .reg = register_snapshot_trigger,
1142 .unreg = unregister_trigger,
1143 .get_trigger_ops = snapshot_get_trigger_ops,
1144 .set_filter = set_trigger_filter,
1145};
1146
1147static __init int register_trigger_snapshot_cmd(void)
1148{
1149 int ret;
1150
1151 ret = register_event_command(&trigger_snapshot_cmd);
1152 WARN_ON(ret < 0);
1153
1154 return ret;
1155}
1156#else
1157static __init int register_trigger_snapshot_cmd(void) { return 0; }
1158#endif /* CONFIG_TRACER_SNAPSHOT */
1159
1160#ifdef CONFIG_STACKTRACE
1161#ifdef CONFIG_UNWINDER_ORC
1162/* Skip 2:
1163 * event_triggers_post_call()
1164 * trace_event_raw_event_xxx()
1165 */
1166# define STACK_SKIP 2
1167#else
1168/*
1169 * Skip 4:
1170 * stacktrace_trigger()
1171 * event_triggers_post_call()
1172 * trace_event_buffer_commit()
1173 * trace_event_raw_event_xxx()
1174 */
1175#define STACK_SKIP 4
1176#endif
1177
1178static void
1179stacktrace_trigger(struct event_trigger_data *data, void *rec,
1180 struct ring_buffer_event *event)
1181{
1182 trace_dump_stack(STACK_SKIP);
1183}
1184
1185static void
1186stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
1187 struct ring_buffer_event *event)
1188{
1189 if (!data->count)
1190 return;
1191
1192 if (data->count != -1)
1193 (data->count)--;
1194
1195 stacktrace_trigger(data, rec, event);
1196}
1197
1198static int
1199stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1200 struct event_trigger_data *data)
1201{
1202 return event_trigger_print("stacktrace", m, (void *)data->count,
1203 data->filter_str);
1204}
1205
1206static struct event_trigger_ops stacktrace_trigger_ops = {
1207 .func = stacktrace_trigger,
1208 .print = stacktrace_trigger_print,
1209 .init = event_trigger_init,
1210 .free = event_trigger_free,
1211};
1212
1213static struct event_trigger_ops stacktrace_count_trigger_ops = {
1214 .func = stacktrace_count_trigger,
1215 .print = stacktrace_trigger_print,
1216 .init = event_trigger_init,
1217 .free = event_trigger_free,
1218};
1219
1220static struct event_trigger_ops *
1221stacktrace_get_trigger_ops(char *cmd, char *param)
1222{
1223 return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1224}
1225
1226static struct event_command trigger_stacktrace_cmd = {
1227 .name = "stacktrace",
1228 .trigger_type = ETT_STACKTRACE,
1229 .flags = EVENT_CMD_FL_POST_TRIGGER,
1230 .func = event_trigger_callback,
1231 .reg = register_trigger,
1232 .unreg = unregister_trigger,
1233 .get_trigger_ops = stacktrace_get_trigger_ops,
1234 .set_filter = set_trigger_filter,
1235};
1236
1237static __init int register_trigger_stacktrace_cmd(void)
1238{
1239 int ret;
1240
1241 ret = register_event_command(&trigger_stacktrace_cmd);
1242 WARN_ON(ret < 0);
1243
1244 return ret;
1245}
1246#else
1247static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1248#endif /* CONFIG_STACKTRACE */
1249
1250static __init void unregister_trigger_traceon_traceoff_cmds(void)
1251{
1252 unregister_event_command(&trigger_traceon_cmd);
1253 unregister_event_command(&trigger_traceoff_cmd);
1254}
1255
1256static void
1257event_enable_trigger(struct event_trigger_data *data, void *rec,
1258 struct ring_buffer_event *event)
1259{
1260 struct enable_trigger_data *enable_data = data->private_data;
1261
1262 if (enable_data->enable)
1263 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1264 else
1265 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1266}
1267
1268static void
1269event_enable_count_trigger(struct event_trigger_data *data, void *rec,
1270 struct ring_buffer_event *event)
1271{
1272 struct enable_trigger_data *enable_data = data->private_data;
1273
1274 if (!data->count)
1275 return;
1276
1277 /* Skip if the event is in a state we want to switch to */
1278 if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1279 return;
1280
1281 if (data->count != -1)
1282 (data->count)--;
1283
1284 event_enable_trigger(data, rec, event);
1285}
1286
1287int event_enable_trigger_print(struct seq_file *m,
1288 struct event_trigger_ops *ops,
1289 struct event_trigger_data *data)
1290{
1291 struct enable_trigger_data *enable_data = data->private_data;
1292
1293 seq_printf(m, "%s:%s:%s",
1294 enable_data->hist ?
1295 (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1296 (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1297 enable_data->file->event_call->class->system,
1298 trace_event_name(enable_data->file->event_call));
1299
1300 if (data->count == -1)
1301 seq_puts(m, ":unlimited");
1302 else
1303 seq_printf(m, ":count=%ld", data->count);
1304
1305 if (data->filter_str)
1306 seq_printf(m, " if %s\n", data->filter_str);
1307 else
1308 seq_putc(m, '\n');
1309
1310 return 0;
1311}
1312
1313void event_enable_trigger_free(struct event_trigger_ops *ops,
1314 struct event_trigger_data *data)
1315{
1316 struct enable_trigger_data *enable_data = data->private_data;
1317
1318 if (WARN_ON_ONCE(data->ref <= 0))
1319 return;
1320
1321 data->ref--;
1322 if (!data->ref) {
1323 /* Remove the SOFT_MODE flag */
1324 trace_event_enable_disable(enable_data->file, 0, 1);
1325 module_put(enable_data->file->event_call->mod);
1326 trigger_data_free(data);
1327 kfree(enable_data);
1328 }
1329}
1330
1331static struct event_trigger_ops event_enable_trigger_ops = {
1332 .func = event_enable_trigger,
1333 .print = event_enable_trigger_print,
1334 .init = event_trigger_init,
1335 .free = event_enable_trigger_free,
1336};
1337
1338static struct event_trigger_ops event_enable_count_trigger_ops = {
1339 .func = event_enable_count_trigger,
1340 .print = event_enable_trigger_print,
1341 .init = event_trigger_init,
1342 .free = event_enable_trigger_free,
1343};
1344
1345static struct event_trigger_ops event_disable_trigger_ops = {
1346 .func = event_enable_trigger,
1347 .print = event_enable_trigger_print,
1348 .init = event_trigger_init,
1349 .free = event_enable_trigger_free,
1350};
1351
1352static struct event_trigger_ops event_disable_count_trigger_ops = {
1353 .func = event_enable_count_trigger,
1354 .print = event_enable_trigger_print,
1355 .init = event_trigger_init,
1356 .free = event_enable_trigger_free,
1357};
1358
1359int event_enable_trigger_func(struct event_command *cmd_ops,
1360 struct trace_event_file *file,
1361 char *glob, char *cmd, char *param)
1362{
1363 struct trace_event_file *event_enable_file;
1364 struct enable_trigger_data *enable_data;
1365 struct event_trigger_data *trigger_data;
1366 struct event_trigger_ops *trigger_ops;
1367 struct trace_array *tr = file->tr;
1368 const char *system;
1369 const char *event;
1370 bool hist = false;
1371 char *trigger;
1372 char *number;
1373 bool enable;
1374 int ret;
1375
1376 if (!param)
1377 return -EINVAL;
1378
1379 /* separate the trigger from the filter (s:e:n [if filter]) */
1380 trigger = strsep(¶m, " \t");
1381 if (!trigger)
1382 return -EINVAL;
1383 if (param) {
1384 param = skip_spaces(param);
1385 if (!*param)
1386 param = NULL;
1387 }
1388
1389 system = strsep(&trigger, ":");
1390 if (!trigger)
1391 return -EINVAL;
1392
1393 event = strsep(&trigger, ":");
1394
1395 ret = -EINVAL;
1396 event_enable_file = find_event_file(tr, system, event);
1397 if (!event_enable_file)
1398 goto out;
1399
1400#ifdef CONFIG_HIST_TRIGGERS
1401 hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1402 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1403
1404 enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1405 (strcmp(cmd, ENABLE_HIST_STR) == 0));
1406#else
1407 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1408#endif
1409 trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1410
1411 ret = -ENOMEM;
1412 trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1413 if (!trigger_data)
1414 goto out;
1415
1416 enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1417 if (!enable_data) {
1418 kfree(trigger_data);
1419 goto out;
1420 }
1421
1422 trigger_data->count = -1;
1423 trigger_data->ops = trigger_ops;
1424 trigger_data->cmd_ops = cmd_ops;
1425 INIT_LIST_HEAD(&trigger_data->list);
1426 RCU_INIT_POINTER(trigger_data->filter, NULL);
1427
1428 enable_data->hist = hist;
1429 enable_data->enable = enable;
1430 enable_data->file = event_enable_file;
1431 trigger_data->private_data = enable_data;
1432
1433 if (glob[0] == '!') {
1434 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1435 kfree(trigger_data);
1436 kfree(enable_data);
1437 ret = 0;
1438 goto out;
1439 }
1440
1441 /* Up the trigger_data count to make sure nothing frees it on failure */
1442 event_trigger_init(trigger_ops, trigger_data);
1443
1444 if (trigger) {
1445 number = strsep(&trigger, ":");
1446
1447 ret = -EINVAL;
1448 if (!strlen(number))
1449 goto out_free;
1450
1451 /*
1452 * We use the callback data field (which is a pointer)
1453 * as our counter.
1454 */
1455 ret = kstrtoul(number, 0, &trigger_data->count);
1456 if (ret)
1457 goto out_free;
1458 }
1459
1460 if (!param) /* if param is non-empty, it's supposed to be a filter */
1461 goto out_reg;
1462
1463 if (!cmd_ops->set_filter)
1464 goto out_reg;
1465
1466 ret = cmd_ops->set_filter(param, trigger_data, file);
1467 if (ret < 0)
1468 goto out_free;
1469
1470 out_reg:
1471 /* Don't let event modules unload while probe registered */
1472 ret = try_module_get(event_enable_file->event_call->mod);
1473 if (!ret) {
1474 ret = -EBUSY;
1475 goto out_free;
1476 }
1477
1478 ret = trace_event_enable_disable(event_enable_file, 1, 1);
1479 if (ret < 0)
1480 goto out_put;
1481 ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1482 /*
1483 * The above returns on success the # of functions enabled,
1484 * but if it didn't find any functions it returns zero.
1485 * Consider no functions a failure too.
1486 */
1487 if (!ret) {
1488 ret = -ENOENT;
1489 goto out_disable;
1490 } else if (ret < 0)
1491 goto out_disable;
1492 /* Just return zero, not the number of enabled functions */
1493 ret = 0;
1494 event_trigger_free(trigger_ops, trigger_data);
1495 out:
1496 return ret;
1497
1498 out_disable:
1499 trace_event_enable_disable(event_enable_file, 0, 1);
1500 out_put:
1501 module_put(event_enable_file->event_call->mod);
1502 out_free:
1503 if (cmd_ops->set_filter)
1504 cmd_ops->set_filter(NULL, trigger_data, NULL);
1505 event_trigger_free(trigger_ops, trigger_data);
1506 kfree(enable_data);
1507 goto out;
1508}
1509
1510int event_enable_register_trigger(char *glob,
1511 struct event_trigger_ops *ops,
1512 struct event_trigger_data *data,
1513 struct trace_event_file *file)
1514{
1515 struct enable_trigger_data *enable_data = data->private_data;
1516 struct enable_trigger_data *test_enable_data;
1517 struct event_trigger_data *test;
1518 int ret = 0;
1519
1520 lockdep_assert_held(&event_mutex);
1521
1522 list_for_each_entry(test, &file->triggers, list) {
1523 test_enable_data = test->private_data;
1524 if (test_enable_data &&
1525 (test->cmd_ops->trigger_type ==
1526 data->cmd_ops->trigger_type) &&
1527 (test_enable_data->file == enable_data->file)) {
1528 ret = -EEXIST;
1529 goto out;
1530 }
1531 }
1532
1533 if (data->ops->init) {
1534 ret = data->ops->init(data->ops, data);
1535 if (ret < 0)
1536 goto out;
1537 }
1538
1539 list_add_rcu(&data->list, &file->triggers);
1540 ret++;
1541
1542 update_cond_flag(file);
1543 if (trace_event_trigger_enable_disable(file, 1) < 0) {
1544 list_del_rcu(&data->list);
1545 update_cond_flag(file);
1546 ret--;
1547 }
1548out:
1549 return ret;
1550}
1551
1552void event_enable_unregister_trigger(char *glob,
1553 struct event_trigger_ops *ops,
1554 struct event_trigger_data *test,
1555 struct trace_event_file *file)
1556{
1557 struct enable_trigger_data *test_enable_data = test->private_data;
1558 struct enable_trigger_data *enable_data;
1559 struct event_trigger_data *data;
1560 bool unregistered = false;
1561
1562 lockdep_assert_held(&event_mutex);
1563
1564 list_for_each_entry(data, &file->triggers, list) {
1565 enable_data = data->private_data;
1566 if (enable_data &&
1567 (data->cmd_ops->trigger_type ==
1568 test->cmd_ops->trigger_type) &&
1569 (enable_data->file == test_enable_data->file)) {
1570 unregistered = true;
1571 list_del_rcu(&data->list);
1572 trace_event_trigger_enable_disable(file, 0);
1573 update_cond_flag(file);
1574 break;
1575 }
1576 }
1577
1578 if (unregistered && data->ops->free)
1579 data->ops->free(data->ops, data);
1580}
1581
1582static struct event_trigger_ops *
1583event_enable_get_trigger_ops(char *cmd, char *param)
1584{
1585 struct event_trigger_ops *ops;
1586 bool enable;
1587
1588#ifdef CONFIG_HIST_TRIGGERS
1589 enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1590 (strcmp(cmd, ENABLE_HIST_STR) == 0));
1591#else
1592 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1593#endif
1594 if (enable)
1595 ops = param ? &event_enable_count_trigger_ops :
1596 &event_enable_trigger_ops;
1597 else
1598 ops = param ? &event_disable_count_trigger_ops :
1599 &event_disable_trigger_ops;
1600
1601 return ops;
1602}
1603
1604static struct event_command trigger_enable_cmd = {
1605 .name = ENABLE_EVENT_STR,
1606 .trigger_type = ETT_EVENT_ENABLE,
1607 .func = event_enable_trigger_func,
1608 .reg = event_enable_register_trigger,
1609 .unreg = event_enable_unregister_trigger,
1610 .get_trigger_ops = event_enable_get_trigger_ops,
1611 .set_filter = set_trigger_filter,
1612};
1613
1614static struct event_command trigger_disable_cmd = {
1615 .name = DISABLE_EVENT_STR,
1616 .trigger_type = ETT_EVENT_ENABLE,
1617 .func = event_enable_trigger_func,
1618 .reg = event_enable_register_trigger,
1619 .unreg = event_enable_unregister_trigger,
1620 .get_trigger_ops = event_enable_get_trigger_ops,
1621 .set_filter = set_trigger_filter,
1622};
1623
1624static __init void unregister_trigger_enable_disable_cmds(void)
1625{
1626 unregister_event_command(&trigger_enable_cmd);
1627 unregister_event_command(&trigger_disable_cmd);
1628}
1629
1630static __init int register_trigger_enable_disable_cmds(void)
1631{
1632 int ret;
1633
1634 ret = register_event_command(&trigger_enable_cmd);
1635 if (WARN_ON(ret < 0))
1636 return ret;
1637 ret = register_event_command(&trigger_disable_cmd);
1638 if (WARN_ON(ret < 0))
1639 unregister_trigger_enable_disable_cmds();
1640
1641 return ret;
1642}
1643
1644static __init int register_trigger_traceon_traceoff_cmds(void)
1645{
1646 int ret;
1647
1648 ret = register_event_command(&trigger_traceon_cmd);
1649 if (WARN_ON(ret < 0))
1650 return ret;
1651 ret = register_event_command(&trigger_traceoff_cmd);
1652 if (WARN_ON(ret < 0))
1653 unregister_trigger_traceon_traceoff_cmds();
1654
1655 return ret;
1656}
1657
1658__init int register_trigger_cmds(void)
1659{
1660 register_trigger_traceon_traceoff_cmds();
1661 register_trigger_snapshot_cmd();
1662 register_trigger_stacktrace_cmd();
1663 register_trigger_enable_disable_cmds();
1664 register_trigger_hist_enable_disable_cmds();
1665 register_trigger_hist_cmd();
1666
1667 return 0;
1668}