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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}