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