xref: /linux/kernel/trace/trace_events_trigger.c (revision e8744fbc83188693f3590020b14d50df3387fc5a)
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 
trigger_data_free(struct event_trigger_data * data)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  * @buffer: The ring buffer that the event is being written to
35  * @rec: The trace entry for the event, NULL for unconditional invocation
36  * @event: The event meta data in the ring buffer
37  *
38  * For each trigger associated with an event, invoke the trigger
39  * function registered with the associated trigger command.  If rec is
40  * non-NULL, it means that the trigger requires further processing and
41  * shouldn't be unconditionally invoked.  If rec is non-NULL and the
42  * trigger has a filter associated with it, rec will checked against
43  * the filter and if the record matches the trigger will be invoked.
44  * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
45  * in any case until the current event is written, the trigger
46  * function isn't invoked but the bit associated with the deferred
47  * trigger is set in the return value.
48  *
49  * Returns an enum event_trigger_type value containing a set bit for
50  * any trigger that should be deferred, ETT_NONE if nothing to defer.
51  *
52  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
53  *
54  * Return: an enum event_trigger_type value containing a set bit for
55  * any trigger that should be deferred, ETT_NONE if nothing to defer.
56  */
57 enum event_trigger_type
event_triggers_call(struct trace_event_file * file,struct trace_buffer * buffer,void * rec,struct ring_buffer_event * event)58 event_triggers_call(struct trace_event_file *file,
59 		    struct trace_buffer *buffer, void *rec,
60 		    struct ring_buffer_event *event)
61 {
62 	struct event_trigger_data *data;
63 	enum event_trigger_type tt = ETT_NONE;
64 	struct event_filter *filter;
65 
66 	if (list_empty(&file->triggers))
67 		return tt;
68 
69 	list_for_each_entry_rcu(data, &file->triggers, list) {
70 		if (data->paused)
71 			continue;
72 		if (!rec) {
73 			data->ops->trigger(data, buffer, rec, event);
74 			continue;
75 		}
76 		filter = rcu_dereference_sched(data->filter);
77 		if (filter && !filter_match_preds(filter, rec))
78 			continue;
79 		if (event_command_post_trigger(data->cmd_ops)) {
80 			tt |= data->cmd_ops->trigger_type;
81 			continue;
82 		}
83 		data->ops->trigger(data, buffer, rec, event);
84 	}
85 	return tt;
86 }
87 EXPORT_SYMBOL_GPL(event_triggers_call);
88 
__trace_trigger_soft_disabled(struct trace_event_file * file)89 bool __trace_trigger_soft_disabled(struct trace_event_file *file)
90 {
91 	unsigned long eflags = file->flags;
92 
93 	if (eflags & EVENT_FILE_FL_TRIGGER_MODE)
94 		event_triggers_call(file, NULL, NULL, NULL);
95 	if (eflags & EVENT_FILE_FL_SOFT_DISABLED)
96 		return true;
97 	if (eflags & EVENT_FILE_FL_PID_FILTER)
98 		return trace_event_ignore_this_pid(file);
99 	return false;
100 }
101 EXPORT_SYMBOL_GPL(__trace_trigger_soft_disabled);
102 
103 /**
104  * event_triggers_post_call - Call 'post_triggers' for a trace event
105  * @file: The trace_event_file associated with the event
106  * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
107  *
108  * For each trigger associated with an event, invoke the trigger
109  * function registered with the associated trigger command, if the
110  * corresponding bit is set in the tt enum passed into this function.
111  * See @event_triggers_call for details on how those bits are set.
112  *
113  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
114  */
115 void
event_triggers_post_call(struct trace_event_file * file,enum event_trigger_type tt)116 event_triggers_post_call(struct trace_event_file *file,
117 			 enum event_trigger_type tt)
118 {
119 	struct event_trigger_data *data;
120 
121 	list_for_each_entry_rcu(data, &file->triggers, list) {
122 		if (data->paused)
123 			continue;
124 		if (data->cmd_ops->trigger_type & tt)
125 			data->ops->trigger(data, NULL, NULL, NULL);
126 	}
127 }
128 EXPORT_SYMBOL_GPL(event_triggers_post_call);
129 
130 #define SHOW_AVAILABLE_TRIGGERS	(void *)(1UL)
131 
trigger_next(struct seq_file * m,void * t,loff_t * pos)132 static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
133 {
134 	struct trace_event_file *event_file = event_file_data(m->private);
135 
136 	if (t == SHOW_AVAILABLE_TRIGGERS) {
137 		(*pos)++;
138 		return NULL;
139 	}
140 	return seq_list_next(t, &event_file->triggers, pos);
141 }
142 
check_user_trigger(struct trace_event_file * file)143 static bool check_user_trigger(struct trace_event_file *file)
144 {
145 	struct event_trigger_data *data;
146 
147 	list_for_each_entry_rcu(data, &file->triggers, list,
148 				lockdep_is_held(&event_mutex)) {
149 		if (data->flags & EVENT_TRIGGER_FL_PROBE)
150 			continue;
151 		return true;
152 	}
153 	return false;
154 }
155 
trigger_start(struct seq_file * m,loff_t * pos)156 static void *trigger_start(struct seq_file *m, loff_t *pos)
157 {
158 	struct trace_event_file *event_file;
159 
160 	/* ->stop() is called even if ->start() fails */
161 	mutex_lock(&event_mutex);
162 	event_file = event_file_file(m->private);
163 	if (unlikely(!event_file))
164 		return ERR_PTR(-ENODEV);
165 
166 	if (list_empty(&event_file->triggers) || !check_user_trigger(event_file))
167 		return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
168 
169 	return seq_list_start(&event_file->triggers, *pos);
170 }
171 
trigger_stop(struct seq_file * m,void * t)172 static void trigger_stop(struct seq_file *m, void *t)
173 {
174 	mutex_unlock(&event_mutex);
175 }
176 
trigger_show(struct seq_file * m,void * v)177 static int trigger_show(struct seq_file *m, void *v)
178 {
179 	struct event_trigger_data *data;
180 	struct event_command *p;
181 
182 	if (v == SHOW_AVAILABLE_TRIGGERS) {
183 		seq_puts(m, "# Available triggers:\n");
184 		seq_putc(m, '#');
185 		mutex_lock(&trigger_cmd_mutex);
186 		list_for_each_entry_reverse(p, &trigger_commands, list)
187 			seq_printf(m, " %s", p->name);
188 		seq_putc(m, '\n');
189 		mutex_unlock(&trigger_cmd_mutex);
190 		return 0;
191 	}
192 
193 	data = list_entry(v, struct event_trigger_data, list);
194 	data->ops->print(m, data);
195 
196 	return 0;
197 }
198 
199 static const struct seq_operations event_triggers_seq_ops = {
200 	.start = trigger_start,
201 	.next = trigger_next,
202 	.stop = trigger_stop,
203 	.show = trigger_show,
204 };
205 
event_trigger_regex_open(struct inode * inode,struct file * file)206 static int event_trigger_regex_open(struct inode *inode, struct file *file)
207 {
208 	int ret;
209 
210 	ret = security_locked_down(LOCKDOWN_TRACEFS);
211 	if (ret)
212 		return ret;
213 
214 	guard(mutex)(&event_mutex);
215 
216 	if (unlikely(!event_file_file(file)))
217 		return -ENODEV;
218 
219 	if ((file->f_mode & FMODE_WRITE) &&
220 	    (file->f_flags & O_TRUNC)) {
221 		struct trace_event_file *event_file;
222 		struct event_command *p;
223 
224 		event_file = event_file_data(file);
225 
226 		list_for_each_entry(p, &trigger_commands, list) {
227 			if (p->unreg_all)
228 				p->unreg_all(event_file);
229 		}
230 	}
231 
232 	if (file->f_mode & FMODE_READ) {
233 		ret = seq_open(file, &event_triggers_seq_ops);
234 		if (!ret) {
235 			struct seq_file *m = file->private_data;
236 			m->private = file;
237 		}
238 	}
239 
240 	return ret;
241 }
242 
trigger_process_regex(struct trace_event_file * file,char * buff)243 int trigger_process_regex(struct trace_event_file *file, char *buff)
244 {
245 	char *command, *next;
246 	struct event_command *p;
247 
248 	next = buff = skip_spaces(buff);
249 	command = strsep(&next, ": \t");
250 	if (next) {
251 		next = skip_spaces(next);
252 		if (!*next)
253 			next = NULL;
254 	}
255 	command = (command[0] != '!') ? command : command + 1;
256 
257 	guard(mutex)(&trigger_cmd_mutex);
258 
259 	list_for_each_entry(p, &trigger_commands, list) {
260 		if (strcmp(p->name, command) == 0)
261 			return p->parse(p, file, buff, command, next);
262 	}
263 
264 	return -EINVAL;
265 }
266 
event_trigger_regex_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)267 static ssize_t event_trigger_regex_write(struct file *file,
268 					 const char __user *ubuf,
269 					 size_t cnt, loff_t *ppos)
270 {
271 	struct trace_event_file *event_file;
272 	ssize_t ret;
273 	char *buf __free(kfree) = NULL;
274 
275 	if (!cnt)
276 		return 0;
277 
278 	if (cnt >= PAGE_SIZE)
279 		return -EINVAL;
280 
281 	buf = memdup_user_nul(ubuf, cnt);
282 	if (IS_ERR(buf))
283 		return PTR_ERR(buf);
284 
285 	strim(buf);
286 
287 	guard(mutex)(&event_mutex);
288 
289 	event_file = event_file_file(file);
290 	if (unlikely(!event_file))
291 		return -ENODEV;
292 
293 	ret = trigger_process_regex(event_file, buf);
294 	if (ret < 0)
295 		return ret;
296 
297 	*ppos += cnt;
298 	return cnt;
299 }
300 
event_trigger_regex_release(struct inode * inode,struct file * file)301 static int event_trigger_regex_release(struct inode *inode, struct file *file)
302 {
303 	mutex_lock(&event_mutex);
304 
305 	if (file->f_mode & FMODE_READ)
306 		seq_release(inode, file);
307 
308 	mutex_unlock(&event_mutex);
309 
310 	return 0;
311 }
312 
313 static ssize_t
event_trigger_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)314 event_trigger_write(struct file *filp, const char __user *ubuf,
315 		    size_t cnt, loff_t *ppos)
316 {
317 	return event_trigger_regex_write(filp, ubuf, cnt, ppos);
318 }
319 
320 static int
event_trigger_open(struct inode * inode,struct file * filp)321 event_trigger_open(struct inode *inode, struct file *filp)
322 {
323 	/* Checks for tracefs lockdown */
324 	return event_trigger_regex_open(inode, filp);
325 }
326 
327 static int
event_trigger_release(struct inode * inode,struct file * file)328 event_trigger_release(struct inode *inode, struct file *file)
329 {
330 	return event_trigger_regex_release(inode, file);
331 }
332 
333 const struct file_operations event_trigger_fops = {
334 	.open = event_trigger_open,
335 	.read = seq_read,
336 	.write = event_trigger_write,
337 	.llseek = tracing_lseek,
338 	.release = event_trigger_release,
339 };
340 
341 /*
342  * Currently we only register event commands from __init, so mark this
343  * __init too.
344  */
register_event_command(struct event_command * cmd)345 __init int register_event_command(struct event_command *cmd)
346 {
347 	struct event_command *p;
348 
349 	guard(mutex)(&trigger_cmd_mutex);
350 
351 	list_for_each_entry(p, &trigger_commands, list) {
352 		if (strcmp(cmd->name, p->name) == 0)
353 			return -EBUSY;
354 	}
355 	list_add(&cmd->list, &trigger_commands);
356 
357 	return 0;
358 }
359 
360 /*
361  * Currently we only unregister event commands from __init, so mark
362  * this __init too.
363  */
unregister_event_command(struct event_command * cmd)364 __init int unregister_event_command(struct event_command *cmd)
365 {
366 	struct event_command *p, *n;
367 
368 	guard(mutex)(&trigger_cmd_mutex);
369 
370 	list_for_each_entry_safe(p, n, &trigger_commands, list) {
371 		if (strcmp(cmd->name, p->name) == 0) {
372 			list_del_init(&p->list);
373 			return 0;
374 		}
375 	}
376 
377 	return -ENODEV;
378 }
379 
380 /**
381  * event_trigger_print - Generic event_trigger_ops @print implementation
382  * @name: The name of the event trigger
383  * @m: The seq_file being printed to
384  * @data: Trigger-specific data
385  * @filter_str: filter_str to print, if present
386  *
387  * Common implementation for event triggers to print themselves.
388  *
389  * Usually wrapped by a function that simply sets the @name of the
390  * trigger command and then invokes this.
391  *
392  * Return: 0 on success, errno otherwise
393  */
394 static int
event_trigger_print(const char * name,struct seq_file * m,void * data,char * filter_str)395 event_trigger_print(const char *name, struct seq_file *m,
396 		    void *data, char *filter_str)
397 {
398 	long count = (long)data;
399 
400 	seq_puts(m, name);
401 
402 	if (count == -1)
403 		seq_puts(m, ":unlimited");
404 	else
405 		seq_printf(m, ":count=%ld", count);
406 
407 	if (filter_str)
408 		seq_printf(m, " if %s\n", filter_str);
409 	else
410 		seq_putc(m, '\n');
411 
412 	return 0;
413 }
414 
415 /**
416  * event_trigger_init - Generic event_trigger_ops @init implementation
417  * @data: Trigger-specific data
418  *
419  * Common implementation of event trigger initialization.
420  *
421  * Usually used directly as the @init method in event trigger
422  * implementations.
423  *
424  * Return: 0 on success, errno otherwise
425  */
event_trigger_init(struct event_trigger_data * data)426 int event_trigger_init(struct event_trigger_data *data)
427 {
428 	data->ref++;
429 	return 0;
430 }
431 
432 /**
433  * event_trigger_free - Generic event_trigger_ops @free implementation
434  * @data: Trigger-specific data
435  *
436  * Common implementation of event trigger de-initialization.
437  *
438  * Usually used directly as the @free method in event trigger
439  * implementations.
440  */
441 static void
event_trigger_free(struct event_trigger_data * data)442 event_trigger_free(struct event_trigger_data *data)
443 {
444 	if (WARN_ON_ONCE(data->ref <= 0))
445 		return;
446 
447 	data->ref--;
448 	if (!data->ref)
449 		trigger_data_free(data);
450 }
451 
trace_event_trigger_enable_disable(struct trace_event_file * file,int trigger_enable)452 int trace_event_trigger_enable_disable(struct trace_event_file *file,
453 				       int trigger_enable)
454 {
455 	int ret = 0;
456 
457 	if (trigger_enable) {
458 		if (atomic_inc_return(&file->tm_ref) > 1)
459 			return ret;
460 		set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
461 		ret = trace_event_enable_disable(file, 1, 1);
462 	} else {
463 		if (atomic_dec_return(&file->tm_ref) > 0)
464 			return ret;
465 		clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
466 		ret = trace_event_enable_disable(file, 0, 1);
467 	}
468 
469 	return ret;
470 }
471 
472 /**
473  * clear_event_triggers - Clear all triggers associated with a trace array
474  * @tr: The trace array to clear
475  *
476  * For each trigger, the triggering event has its tm_ref decremented
477  * via trace_event_trigger_enable_disable(), and any associated event
478  * (in the case of enable/disable_event triggers) will have its sm_ref
479  * decremented via free()->trace_event_enable_disable().  That
480  * combination effectively reverses the soft-mode/trigger state added
481  * by trigger registration.
482  *
483  * Must be called with event_mutex held.
484  */
485 void
clear_event_triggers(struct trace_array * tr)486 clear_event_triggers(struct trace_array *tr)
487 {
488 	struct trace_event_file *file;
489 
490 	list_for_each_entry(file, &tr->events, list) {
491 		struct event_trigger_data *data, *n;
492 		list_for_each_entry_safe(data, n, &file->triggers, list) {
493 			trace_event_trigger_enable_disable(file, 0);
494 			list_del_rcu(&data->list);
495 			if (data->ops->free)
496 				data->ops->free(data);
497 		}
498 	}
499 }
500 
501 /**
502  * update_cond_flag - Set or reset the TRIGGER_COND bit
503  * @file: The trace_event_file associated with the event
504  *
505  * If an event has triggers and any of those triggers has a filter or
506  * a post_trigger, trigger invocation needs to be deferred until after
507  * the current event has logged its data, and the event should have
508  * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
509  * cleared.
510  */
update_cond_flag(struct trace_event_file * file)511 void update_cond_flag(struct trace_event_file *file)
512 {
513 	struct event_trigger_data *data;
514 	bool set_cond = false;
515 
516 	lockdep_assert_held(&event_mutex);
517 
518 	list_for_each_entry(data, &file->triggers, list) {
519 		if (data->filter || event_command_post_trigger(data->cmd_ops) ||
520 		    event_command_needs_rec(data->cmd_ops)) {
521 			set_cond = true;
522 			break;
523 		}
524 	}
525 
526 	if (set_cond)
527 		set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
528 	else
529 		clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
530 }
531 
532 /**
533  * register_trigger - Generic event_command @reg implementation
534  * @glob: The raw string used to register the trigger
535  * @data: Trigger-specific data to associate with the trigger
536  * @file: The trace_event_file associated with the event
537  *
538  * Common implementation for event trigger registration.
539  *
540  * Usually used directly as the @reg method in event command
541  * implementations.
542  *
543  * Return: 0 on success, errno otherwise
544  */
register_trigger(char * glob,struct event_trigger_data * data,struct trace_event_file * file)545 static int register_trigger(char *glob,
546 			    struct event_trigger_data *data,
547 			    struct trace_event_file *file)
548 {
549 	struct event_trigger_data *test;
550 	int ret = 0;
551 
552 	lockdep_assert_held(&event_mutex);
553 
554 	list_for_each_entry(test, &file->triggers, list) {
555 		if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
556 			ret = -EEXIST;
557 			goto out;
558 		}
559 	}
560 
561 	if (data->ops->init) {
562 		ret = data->ops->init(data);
563 		if (ret < 0)
564 			goto out;
565 	}
566 
567 	list_add_rcu(&data->list, &file->triggers);
568 
569 	update_cond_flag(file);
570 	ret = trace_event_trigger_enable_disable(file, 1);
571 	if (ret < 0) {
572 		list_del_rcu(&data->list);
573 		update_cond_flag(file);
574 	}
575 out:
576 	return ret;
577 }
578 
579 /*
580  * True if the trigger was found and unregistered, else false.
581  */
try_unregister_trigger(char * glob,struct event_trigger_data * test,struct trace_event_file * file)582 static bool try_unregister_trigger(char *glob,
583 				   struct event_trigger_data *test,
584 				   struct trace_event_file *file)
585 {
586 	struct event_trigger_data *data = NULL, *iter;
587 
588 	lockdep_assert_held(&event_mutex);
589 
590 	list_for_each_entry(iter, &file->triggers, list) {
591 		if (iter->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
592 			data = iter;
593 			list_del_rcu(&data->list);
594 			trace_event_trigger_enable_disable(file, 0);
595 			update_cond_flag(file);
596 			break;
597 		}
598 	}
599 
600 	if (data) {
601 		if (data->ops->free)
602 			data->ops->free(data);
603 
604 		return true;
605 	}
606 
607 	return false;
608 }
609 
610 /**
611  * unregister_trigger - Generic event_command @unreg implementation
612  * @glob: The raw string used to register the trigger
613  * @test: Trigger-specific data used to find the trigger to remove
614  * @file: The trace_event_file associated with the event
615  *
616  * Common implementation for event trigger unregistration.
617  *
618  * Usually used directly as the @unreg method in event command
619  * implementations.
620  */
unregister_trigger(char * glob,struct event_trigger_data * test,struct trace_event_file * file)621 static void unregister_trigger(char *glob,
622 			       struct event_trigger_data *test,
623 			       struct trace_event_file *file)
624 {
625 	try_unregister_trigger(glob, test, file);
626 }
627 
628 /*
629  * Event trigger parsing helper functions.
630  *
631  * These functions help make it easier to write an event trigger
632  * parsing function i.e. the struct event_command.parse() callback
633  * function responsible for parsing and registering a trigger command
634  * written to the 'trigger' file.
635  *
636  * A trigger command (or just 'trigger' for short) takes the form:
637  *   [trigger] [if filter]
638  *
639  * The struct event_command.parse() callback (and other struct
640  * event_command functions) refer to several components of a trigger
641  * command.  Those same components are referenced by the event trigger
642  * parsing helper functions defined below.  These components are:
643  *
644  *   cmd               - the trigger command name
645  *   glob              - the trigger command name optionally prefaced with '!'
646  *   param_and_filter  - text following cmd and ':'
647  *   param             - text following cmd and ':' and stripped of filter
648  *   filter            - the optional filter text following (and including) 'if'
649  *
650  * To illustrate the use of these componenents, here are some concrete
651  * examples. For the following triggers:
652  *
653  *   echo 'traceon:5 if pid == 0' > trigger
654  *     - 'traceon' is both cmd and glob
655  *     - '5 if pid == 0' is the param_and_filter
656  *     - '5' is the param
657  *     - 'if pid == 0' is the filter
658  *
659  *   echo 'enable_event:sys:event:n' > trigger
660  *     - 'enable_event' is both cmd and glob
661  *     - 'sys:event:n' is the param_and_filter
662  *     - 'sys:event:n' is the param
663  *     - there is no filter
664  *
665  *   echo 'hist:keys=pid if prio > 50' > trigger
666  *     - 'hist' is both cmd and glob
667  *     - 'keys=pid if prio > 50' is the param_and_filter
668  *     - 'keys=pid' is the param
669  *     - 'if prio > 50' is the filter
670  *
671  *   echo '!enable_event:sys:event:n' > trigger
672  *     - 'enable_event' the cmd
673  *     - '!enable_event' is the glob
674  *     - 'sys:event:n' is the param_and_filter
675  *     - 'sys:event:n' is the param
676  *     - there is no filter
677  *
678  *   echo 'traceoff' > trigger
679  *     - 'traceoff' is both cmd and glob
680  *     - there is no param_and_filter
681  *     - there is no param
682  *     - there is no filter
683  *
684  * There are a few different categories of event trigger covered by
685  * these helpers:
686  *
687  *  - triggers that don't require a parameter e.g. traceon
688  *  - triggers that do require a parameter e.g. enable_event and hist
689  *  - triggers that though they may not require a param may support an
690  *    optional 'n' param (n = number of times the trigger should fire)
691  *    e.g.: traceon:5 or enable_event:sys:event:n
692  *  - triggers that do not support an 'n' param e.g. hist
693  *
694  * These functions can be used or ignored as necessary - it all
695  * depends on the complexity of the trigger, and the granularity of
696  * the functions supported reflects the fact that some implementations
697  * may need to customize certain aspects of their implementations and
698  * won't need certain functions.  For instance, the hist trigger
699  * implementation doesn't use event_trigger_separate_filter() because
700  * it has special requirements for handling the filter.
701  */
702 
703 /**
704  * event_trigger_check_remove - check whether an event trigger specifies remove
705  * @glob: The trigger command string, with optional remove(!) operator
706  *
707  * The event trigger callback implementations pass in 'glob' as a
708  * parameter.  This is the command name either with or without a
709  * remove(!)  operator.  This function simply parses the glob and
710  * determines whether the command corresponds to a trigger removal or
711  * a trigger addition.
712  *
713  * Return: true if this is a remove command, false otherwise
714  */
event_trigger_check_remove(const char * glob)715 bool event_trigger_check_remove(const char *glob)
716 {
717 	return (glob && glob[0] == '!') ? true : false;
718 }
719 
720 /**
721  * event_trigger_empty_param - check whether the param is empty
722  * @param: The trigger param string
723  *
724  * The event trigger callback implementations pass in 'param' as a
725  * parameter.  This corresponds to the string following the command
726  * name minus the command name.  This function can be called by a
727  * callback implementation for any command that requires a param; a
728  * callback that doesn't require a param can ignore it.
729  *
730  * Return: true if this is an empty param, false otherwise
731  */
event_trigger_empty_param(const char * param)732 bool event_trigger_empty_param(const char *param)
733 {
734 	return !param;
735 }
736 
737 /**
738  * event_trigger_separate_filter - separate an event trigger from a filter
739  * @param_and_filter: String containing trigger and possibly filter
740  * @param: outparam, will be filled with a pointer to the trigger
741  * @filter: outparam, will be filled with a pointer to the filter
742  * @param_required: Specifies whether or not the param string is required
743  *
744  * Given a param string of the form '[trigger] [if filter]', this
745  * function separates the filter from the trigger and returns the
746  * trigger in @param and the filter in @filter.  Either the @param
747  * or the @filter may be set to NULL by this function - if not set to
748  * NULL, they will contain strings corresponding to the trigger and
749  * filter.
750  *
751  * There are two cases that need to be handled with respect to the
752  * passed-in param: either the param is required, or it is not
753  * required.  If @param_required is set, and there's no param, it will
754  * return -EINVAL.  If @param_required is not set and there's a param
755  * that starts with a number, that corresponds to the case of a
756  * trigger with :n (n = number of times the trigger should fire) and
757  * the parsing continues normally; otherwise the function just returns
758  * and assumes param just contains a filter and there's nothing else
759  * to do.
760  *
761  * Return: 0 on success, errno otherwise
762  */
event_trigger_separate_filter(char * param_and_filter,char ** param,char ** filter,bool param_required)763 int event_trigger_separate_filter(char *param_and_filter, char **param,
764 				  char **filter, bool param_required)
765 {
766 	int ret = 0;
767 
768 	*param = *filter = NULL;
769 
770 	if (!param_and_filter) {
771 		if (param_required)
772 			ret = -EINVAL;
773 		goto out;
774 	}
775 
776 	/*
777 	 * Here we check for an optional param. The only legal
778 	 * optional param is :n, and if that's the case, continue
779 	 * below. Otherwise we assume what's left is a filter and
780 	 * return it as the filter string for the caller to deal with.
781 	 */
782 	if (!param_required && param_and_filter && !isdigit(param_and_filter[0])) {
783 		*filter = param_and_filter;
784 		goto out;
785 	}
786 
787 	/*
788 	 * Separate the param from the filter (param [if filter]).
789 	 * Here we have either an optional :n param or a required
790 	 * param and an optional filter.
791 	 */
792 	*param = strsep(&param_and_filter, " \t");
793 
794 	/*
795 	 * Here we have a filter, though it may be empty.
796 	 */
797 	if (param_and_filter) {
798 		*filter = skip_spaces(param_and_filter);
799 		if (!**filter)
800 			*filter = NULL;
801 	}
802 out:
803 	return ret;
804 }
805 
806 /**
807  * event_trigger_alloc - allocate and init event_trigger_data for a trigger
808  * @cmd_ops: The event_command operations for the trigger
809  * @cmd: The cmd string
810  * @param: The param string
811  * @private_data: User data to associate with the event trigger
812  *
813  * Allocate an event_trigger_data instance and initialize it.  The
814  * @cmd_ops are used along with the @cmd and @param to get the
815  * trigger_ops to assign to the event_trigger_data.  @private_data can
816  * also be passed in and associated with the event_trigger_data.
817  *
818  * Use event_trigger_free() to free an event_trigger_data object.
819  *
820  * Return: The trigger_data object success, NULL otherwise
821  */
event_trigger_alloc(struct event_command * cmd_ops,char * cmd,char * param,void * private_data)822 struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops,
823 					       char *cmd,
824 					       char *param,
825 					       void *private_data)
826 {
827 	struct event_trigger_data *trigger_data;
828 	struct event_trigger_ops *trigger_ops;
829 
830 	trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
831 
832 	trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
833 	if (!trigger_data)
834 		return NULL;
835 
836 	trigger_data->count = -1;
837 	trigger_data->ops = trigger_ops;
838 	trigger_data->cmd_ops = cmd_ops;
839 	trigger_data->private_data = private_data;
840 
841 	INIT_LIST_HEAD(&trigger_data->list);
842 	INIT_LIST_HEAD(&trigger_data->named_list);
843 	RCU_INIT_POINTER(trigger_data->filter, NULL);
844 
845 	return trigger_data;
846 }
847 
848 /**
849  * event_trigger_parse_num - parse and return the number param for a trigger
850  * @param: The param string
851  * @trigger_data: The trigger_data for the trigger
852  *
853  * Parse the :n (n = number of times the trigger should fire) param
854  * and set the count variable in the trigger_data to the parsed count.
855  *
856  * Return: 0 on success, errno otherwise
857  */
event_trigger_parse_num(char * param,struct event_trigger_data * trigger_data)858 int event_trigger_parse_num(char *param,
859 			    struct event_trigger_data *trigger_data)
860 {
861 	char *number;
862 	int ret = 0;
863 
864 	if (param) {
865 		number = strsep(&param, ":");
866 
867 		if (!strlen(number))
868 			return -EINVAL;
869 
870 		/*
871 		 * We use the callback data field (which is a pointer)
872 		 * as our counter.
873 		 */
874 		ret = kstrtoul(number, 0, &trigger_data->count);
875 	}
876 
877 	return ret;
878 }
879 
880 /**
881  * event_trigger_set_filter - set an event trigger's filter
882  * @cmd_ops: The event_command operations for the trigger
883  * @file: The event file for the trigger's event
884  * @param: The string containing the filter
885  * @trigger_data: The trigger_data for the trigger
886  *
887  * Set the filter for the trigger.  If the filter is NULL, just return
888  * without error.
889  *
890  * Return: 0 on success, errno otherwise
891  */
event_trigger_set_filter(struct event_command * cmd_ops,struct trace_event_file * file,char * param,struct event_trigger_data * trigger_data)892 int event_trigger_set_filter(struct event_command *cmd_ops,
893 			     struct trace_event_file *file,
894 			     char *param,
895 			     struct event_trigger_data *trigger_data)
896 {
897 	if (param && cmd_ops->set_filter)
898 		return cmd_ops->set_filter(param, trigger_data, file);
899 
900 	return 0;
901 }
902 
903 /**
904  * event_trigger_reset_filter - reset an event trigger's filter
905  * @cmd_ops: The event_command operations for the trigger
906  * @trigger_data: The trigger_data for the trigger
907  *
908  * Reset the filter for the trigger to no filter.
909  */
event_trigger_reset_filter(struct event_command * cmd_ops,struct event_trigger_data * trigger_data)910 void event_trigger_reset_filter(struct event_command *cmd_ops,
911 				struct event_trigger_data *trigger_data)
912 {
913 	if (cmd_ops->set_filter)
914 		cmd_ops->set_filter(NULL, trigger_data, NULL);
915 }
916 
917 /**
918  * event_trigger_register - register an event trigger
919  * @cmd_ops: The event_command operations for the trigger
920  * @file: The event file for the trigger's event
921  * @glob: The trigger command string, with optional remove(!) operator
922  * @trigger_data: The trigger_data for the trigger
923  *
924  * Register an event trigger.  The @cmd_ops are used to call the
925  * cmd_ops->reg() function which actually does the registration.
926  *
927  * Return: 0 on success, errno otherwise
928  */
event_trigger_register(struct event_command * cmd_ops,struct trace_event_file * file,char * glob,struct event_trigger_data * trigger_data)929 int event_trigger_register(struct event_command *cmd_ops,
930 			   struct trace_event_file *file,
931 			   char *glob,
932 			   struct event_trigger_data *trigger_data)
933 {
934 	return cmd_ops->reg(glob, trigger_data, file);
935 }
936 
937 /**
938  * event_trigger_unregister - unregister an event trigger
939  * @cmd_ops: The event_command operations for the trigger
940  * @file: The event file for the trigger's event
941  * @glob: The trigger command string, with optional remove(!) operator
942  * @trigger_data: The trigger_data for the trigger
943  *
944  * Unregister an event trigger.  The @cmd_ops are used to call the
945  * cmd_ops->unreg() function which actually does the unregistration.
946  */
event_trigger_unregister(struct event_command * cmd_ops,struct trace_event_file * file,char * glob,struct event_trigger_data * trigger_data)947 void event_trigger_unregister(struct event_command *cmd_ops,
948 			      struct trace_event_file *file,
949 			      char *glob,
950 			      struct event_trigger_data *trigger_data)
951 {
952 	cmd_ops->unreg(glob, trigger_data, file);
953 }
954 
955 /*
956  * End event trigger parsing helper functions.
957  */
958 
959 /**
960  * event_trigger_parse - Generic event_command @parse implementation
961  * @cmd_ops: The command ops, used for trigger registration
962  * @file: The trace_event_file associated with the event
963  * @glob: The raw string used to register the trigger
964  * @cmd: The cmd portion of the string used to register the trigger
965  * @param_and_filter: The param and filter portion of the string used to register the trigger
966  *
967  * Common implementation for event command parsing and trigger
968  * instantiation.
969  *
970  * Usually used directly as the @parse method in event command
971  * implementations.
972  *
973  * Return: 0 on success, errno otherwise
974  */
975 static int
event_trigger_parse(struct event_command * cmd_ops,struct trace_event_file * file,char * glob,char * cmd,char * param_and_filter)976 event_trigger_parse(struct event_command *cmd_ops,
977 		    struct trace_event_file *file,
978 		    char *glob, char *cmd, char *param_and_filter)
979 {
980 	struct event_trigger_data *trigger_data;
981 	char *param, *filter;
982 	bool remove;
983 	int ret;
984 
985 	remove = event_trigger_check_remove(glob);
986 
987 	ret = event_trigger_separate_filter(param_and_filter, &param, &filter, false);
988 	if (ret)
989 		return ret;
990 
991 	ret = -ENOMEM;
992 	trigger_data = event_trigger_alloc(cmd_ops, cmd, param, file);
993 	if (!trigger_data)
994 		goto out;
995 
996 	if (remove) {
997 		event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
998 		kfree(trigger_data);
999 		ret = 0;
1000 		goto out;
1001 	}
1002 
1003 	ret = event_trigger_parse_num(param, trigger_data);
1004 	if (ret)
1005 		goto out_free;
1006 
1007 	ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
1008 	if (ret < 0)
1009 		goto out_free;
1010 
1011 	/* Up the trigger_data count to make sure reg doesn't free it on failure */
1012 	event_trigger_init(trigger_data);
1013 
1014 	ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
1015 	if (ret)
1016 		goto out_free;
1017 
1018 	/* Down the counter of trigger_data or free it if not used anymore */
1019 	event_trigger_free(trigger_data);
1020  out:
1021 	return ret;
1022 
1023  out_free:
1024 	event_trigger_reset_filter(cmd_ops, trigger_data);
1025 	kfree(trigger_data);
1026 	goto out;
1027 }
1028 
1029 /**
1030  * set_trigger_filter - Generic event_command @set_filter implementation
1031  * @filter_str: The filter string for the trigger, NULL to remove filter
1032  * @trigger_data: Trigger-specific data
1033  * @file: The trace_event_file associated with the event
1034  *
1035  * Common implementation for event command filter parsing and filter
1036  * instantiation.
1037  *
1038  * Usually used directly as the @set_filter method in event command
1039  * implementations.
1040  *
1041  * Also used to remove a filter (if filter_str = NULL).
1042  *
1043  * Return: 0 on success, errno otherwise
1044  */
set_trigger_filter(char * filter_str,struct event_trigger_data * trigger_data,struct trace_event_file * file)1045 int set_trigger_filter(char *filter_str,
1046 		       struct event_trigger_data *trigger_data,
1047 		       struct trace_event_file *file)
1048 {
1049 	struct event_trigger_data *data = trigger_data;
1050 	struct event_filter *filter = NULL, *tmp;
1051 	int ret = -EINVAL;
1052 	char *s;
1053 
1054 	if (!filter_str) /* clear the current filter */
1055 		goto assign;
1056 
1057 	s = strsep(&filter_str, " \t");
1058 
1059 	if (!strlen(s) || strcmp(s, "if") != 0)
1060 		goto out;
1061 
1062 	if (!filter_str)
1063 		goto out;
1064 
1065 	/* The filter is for the 'trigger' event, not the triggered event */
1066 	ret = create_event_filter(file->tr, file->event_call,
1067 				  filter_str, true, &filter);
1068 
1069 	/* Only enabled set_str for error handling */
1070 	if (filter) {
1071 		kfree(filter->filter_string);
1072 		filter->filter_string = NULL;
1073 	}
1074 
1075 	/*
1076 	 * If create_event_filter() fails, filter still needs to be freed.
1077 	 * Which the calling code will do with data->filter.
1078 	 */
1079  assign:
1080 	tmp = rcu_access_pointer(data->filter);
1081 
1082 	rcu_assign_pointer(data->filter, filter);
1083 
1084 	if (tmp) {
1085 		/*
1086 		 * Make sure the call is done with the filter.
1087 		 * It is possible that a filter could fail at boot up,
1088 		 * and then this path will be called. Avoid the synchronization
1089 		 * in that case.
1090 		 */
1091 		if (system_state != SYSTEM_BOOTING)
1092 			tracepoint_synchronize_unregister();
1093 		free_event_filter(tmp);
1094 	}
1095 
1096 	kfree(data->filter_str);
1097 	data->filter_str = NULL;
1098 
1099 	if (filter_str) {
1100 		data->filter_str = kstrdup(filter_str, GFP_KERNEL);
1101 		if (!data->filter_str) {
1102 			free_event_filter(rcu_access_pointer(data->filter));
1103 			data->filter = NULL;
1104 			ret = -ENOMEM;
1105 		}
1106 	}
1107  out:
1108 	return ret;
1109 }
1110 
1111 static LIST_HEAD(named_triggers);
1112 
1113 /**
1114  * find_named_trigger - Find the common named trigger associated with @name
1115  * @name: The name of the set of named triggers to find the common data for
1116  *
1117  * Named triggers are sets of triggers that share a common set of
1118  * trigger data.  The first named trigger registered with a given name
1119  * owns the common trigger data that the others subsequently
1120  * registered with the same name will reference.  This function
1121  * returns the common trigger data associated with that first
1122  * registered instance.
1123  *
1124  * Return: the common trigger data for the given named trigger on
1125  * success, NULL otherwise.
1126  */
find_named_trigger(const char * name)1127 struct event_trigger_data *find_named_trigger(const char *name)
1128 {
1129 	struct event_trigger_data *data;
1130 
1131 	if (!name)
1132 		return NULL;
1133 
1134 	list_for_each_entry(data, &named_triggers, named_list) {
1135 		if (data->named_data)
1136 			continue;
1137 		if (strcmp(data->name, name) == 0)
1138 			return data;
1139 	}
1140 
1141 	return NULL;
1142 }
1143 
1144 /**
1145  * is_named_trigger - determine if a given trigger is a named trigger
1146  * @test: The trigger data to test
1147  *
1148  * Return: true if 'test' is a named trigger, false otherwise.
1149  */
is_named_trigger(struct event_trigger_data * test)1150 bool is_named_trigger(struct event_trigger_data *test)
1151 {
1152 	struct event_trigger_data *data;
1153 
1154 	list_for_each_entry(data, &named_triggers, named_list) {
1155 		if (test == data)
1156 			return true;
1157 	}
1158 
1159 	return false;
1160 }
1161 
1162 /**
1163  * save_named_trigger - save the trigger in the named trigger list
1164  * @name: The name of the named trigger set
1165  * @data: The trigger data to save
1166  *
1167  * Return: 0 if successful, negative error otherwise.
1168  */
save_named_trigger(const char * name,struct event_trigger_data * data)1169 int save_named_trigger(const char *name, struct event_trigger_data *data)
1170 {
1171 	data->name = kstrdup(name, GFP_KERNEL);
1172 	if (!data->name)
1173 		return -ENOMEM;
1174 
1175 	list_add(&data->named_list, &named_triggers);
1176 
1177 	return 0;
1178 }
1179 
1180 /**
1181  * del_named_trigger - delete a trigger from the named trigger list
1182  * @data: The trigger data to delete
1183  */
del_named_trigger(struct event_trigger_data * data)1184 void del_named_trigger(struct event_trigger_data *data)
1185 {
1186 	kfree(data->name);
1187 	data->name = NULL;
1188 
1189 	list_del(&data->named_list);
1190 }
1191 
__pause_named_trigger(struct event_trigger_data * data,bool pause)1192 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
1193 {
1194 	struct event_trigger_data *test;
1195 
1196 	list_for_each_entry(test, &named_triggers, named_list) {
1197 		if (strcmp(test->name, data->name) == 0) {
1198 			if (pause) {
1199 				test->paused_tmp = test->paused;
1200 				test->paused = true;
1201 			} else {
1202 				test->paused = test->paused_tmp;
1203 			}
1204 		}
1205 	}
1206 }
1207 
1208 /**
1209  * pause_named_trigger - Pause all named triggers with the same name
1210  * @data: The trigger data of a named trigger to pause
1211  *
1212  * Pauses a named trigger along with all other triggers having the
1213  * same name.  Because named triggers share a common set of data,
1214  * pausing only one is meaningless, so pausing one named trigger needs
1215  * to pause all triggers with the same name.
1216  */
pause_named_trigger(struct event_trigger_data * data)1217 void pause_named_trigger(struct event_trigger_data *data)
1218 {
1219 	__pause_named_trigger(data, true);
1220 }
1221 
1222 /**
1223  * unpause_named_trigger - Un-pause all named triggers with the same name
1224  * @data: The trigger data of a named trigger to unpause
1225  *
1226  * Un-pauses a named trigger along with all other triggers having the
1227  * same name.  Because named triggers share a common set of data,
1228  * unpausing only one is meaningless, so unpausing one named trigger
1229  * needs to unpause all triggers with the same name.
1230  */
unpause_named_trigger(struct event_trigger_data * data)1231 void unpause_named_trigger(struct event_trigger_data *data)
1232 {
1233 	__pause_named_trigger(data, false);
1234 }
1235 
1236 /**
1237  * set_named_trigger_data - Associate common named trigger data
1238  * @data: The trigger data to associate
1239  * @named_data: The common named trigger to be associated
1240  *
1241  * Named triggers are sets of triggers that share a common set of
1242  * trigger data.  The first named trigger registered with a given name
1243  * owns the common trigger data that the others subsequently
1244  * registered with the same name will reference.  This function
1245  * associates the common trigger data from the first trigger with the
1246  * given trigger.
1247  */
set_named_trigger_data(struct event_trigger_data * data,struct event_trigger_data * named_data)1248 void set_named_trigger_data(struct event_trigger_data *data,
1249 			    struct event_trigger_data *named_data)
1250 {
1251 	data->named_data = named_data;
1252 }
1253 
1254 struct event_trigger_data *
get_named_trigger_data(struct event_trigger_data * data)1255 get_named_trigger_data(struct event_trigger_data *data)
1256 {
1257 	return data->named_data;
1258 }
1259 
1260 static void
traceon_trigger(struct event_trigger_data * data,struct trace_buffer * buffer,void * rec,struct ring_buffer_event * event)1261 traceon_trigger(struct event_trigger_data *data,
1262 		struct trace_buffer *buffer, void *rec,
1263 		struct ring_buffer_event *event)
1264 {
1265 	struct trace_event_file *file = data->private_data;
1266 
1267 	if (file) {
1268 		if (tracer_tracing_is_on(file->tr))
1269 			return;
1270 
1271 		tracer_tracing_on(file->tr);
1272 		return;
1273 	}
1274 
1275 	if (tracing_is_on())
1276 		return;
1277 
1278 	tracing_on();
1279 }
1280 
1281 static void
traceon_count_trigger(struct event_trigger_data * data,struct trace_buffer * buffer,void * rec,struct ring_buffer_event * event)1282 traceon_count_trigger(struct event_trigger_data *data,
1283 		      struct trace_buffer *buffer, void *rec,
1284 		      struct ring_buffer_event *event)
1285 {
1286 	struct trace_event_file *file = data->private_data;
1287 
1288 	if (file) {
1289 		if (tracer_tracing_is_on(file->tr))
1290 			return;
1291 	} else {
1292 		if (tracing_is_on())
1293 			return;
1294 	}
1295 
1296 	if (!data->count)
1297 		return;
1298 
1299 	if (data->count != -1)
1300 		(data->count)--;
1301 
1302 	if (file)
1303 		tracer_tracing_on(file->tr);
1304 	else
1305 		tracing_on();
1306 }
1307 
1308 static void
traceoff_trigger(struct event_trigger_data * data,struct trace_buffer * buffer,void * rec,struct ring_buffer_event * event)1309 traceoff_trigger(struct event_trigger_data *data,
1310 		 struct trace_buffer *buffer, void *rec,
1311 		 struct ring_buffer_event *event)
1312 {
1313 	struct trace_event_file *file = data->private_data;
1314 
1315 	if (file) {
1316 		if (!tracer_tracing_is_on(file->tr))
1317 			return;
1318 
1319 		tracer_tracing_off(file->tr);
1320 		return;
1321 	}
1322 
1323 	if (!tracing_is_on())
1324 		return;
1325 
1326 	tracing_off();
1327 }
1328 
1329 static void
traceoff_count_trigger(struct event_trigger_data * data,struct trace_buffer * buffer,void * rec,struct ring_buffer_event * event)1330 traceoff_count_trigger(struct event_trigger_data *data,
1331 		       struct trace_buffer *buffer, void *rec,
1332 		       struct ring_buffer_event *event)
1333 {
1334 	struct trace_event_file *file = data->private_data;
1335 
1336 	if (file) {
1337 		if (!tracer_tracing_is_on(file->tr))
1338 			return;
1339 	} else {
1340 		if (!tracing_is_on())
1341 			return;
1342 	}
1343 
1344 	if (!data->count)
1345 		return;
1346 
1347 	if (data->count != -1)
1348 		(data->count)--;
1349 
1350 	if (file)
1351 		tracer_tracing_off(file->tr);
1352 	else
1353 		tracing_off();
1354 }
1355 
1356 static int
traceon_trigger_print(struct seq_file * m,struct event_trigger_data * data)1357 traceon_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1358 {
1359 	return event_trigger_print("traceon", m, (void *)data->count,
1360 				   data->filter_str);
1361 }
1362 
1363 static int
traceoff_trigger_print(struct seq_file * m,struct event_trigger_data * data)1364 traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1365 {
1366 	return event_trigger_print("traceoff", m, (void *)data->count,
1367 				   data->filter_str);
1368 }
1369 
1370 static struct event_trigger_ops traceon_trigger_ops = {
1371 	.trigger		= traceon_trigger,
1372 	.print			= traceon_trigger_print,
1373 	.init			= event_trigger_init,
1374 	.free			= event_trigger_free,
1375 };
1376 
1377 static struct event_trigger_ops traceon_count_trigger_ops = {
1378 	.trigger		= traceon_count_trigger,
1379 	.print			= traceon_trigger_print,
1380 	.init			= event_trigger_init,
1381 	.free			= event_trigger_free,
1382 };
1383 
1384 static struct event_trigger_ops traceoff_trigger_ops = {
1385 	.trigger		= traceoff_trigger,
1386 	.print			= traceoff_trigger_print,
1387 	.init			= event_trigger_init,
1388 	.free			= event_trigger_free,
1389 };
1390 
1391 static struct event_trigger_ops traceoff_count_trigger_ops = {
1392 	.trigger		= traceoff_count_trigger,
1393 	.print			= traceoff_trigger_print,
1394 	.init			= event_trigger_init,
1395 	.free			= event_trigger_free,
1396 };
1397 
1398 static struct event_trigger_ops *
onoff_get_trigger_ops(char * cmd,char * param)1399 onoff_get_trigger_ops(char *cmd, char *param)
1400 {
1401 	struct event_trigger_ops *ops;
1402 
1403 	/* we register both traceon and traceoff to this callback */
1404 	if (strcmp(cmd, "traceon") == 0)
1405 		ops = param ? &traceon_count_trigger_ops :
1406 			&traceon_trigger_ops;
1407 	else
1408 		ops = param ? &traceoff_count_trigger_ops :
1409 			&traceoff_trigger_ops;
1410 
1411 	return ops;
1412 }
1413 
1414 static struct event_command trigger_traceon_cmd = {
1415 	.name			= "traceon",
1416 	.trigger_type		= ETT_TRACE_ONOFF,
1417 	.parse			= event_trigger_parse,
1418 	.reg			= register_trigger,
1419 	.unreg			= unregister_trigger,
1420 	.get_trigger_ops	= onoff_get_trigger_ops,
1421 	.set_filter		= set_trigger_filter,
1422 };
1423 
1424 static struct event_command trigger_traceoff_cmd = {
1425 	.name			= "traceoff",
1426 	.trigger_type		= ETT_TRACE_ONOFF,
1427 	.flags			= EVENT_CMD_FL_POST_TRIGGER,
1428 	.parse			= event_trigger_parse,
1429 	.reg			= register_trigger,
1430 	.unreg			= unregister_trigger,
1431 	.get_trigger_ops	= onoff_get_trigger_ops,
1432 	.set_filter		= set_trigger_filter,
1433 };
1434 
1435 #ifdef CONFIG_TRACER_SNAPSHOT
1436 static void
snapshot_trigger(struct event_trigger_data * data,struct trace_buffer * buffer,void * rec,struct ring_buffer_event * event)1437 snapshot_trigger(struct event_trigger_data *data,
1438 		 struct trace_buffer *buffer, void *rec,
1439 		 struct ring_buffer_event *event)
1440 {
1441 	struct trace_event_file *file = data->private_data;
1442 
1443 	if (file)
1444 		tracing_snapshot_instance(file->tr);
1445 	else
1446 		tracing_snapshot();
1447 }
1448 
1449 static void
snapshot_count_trigger(struct event_trigger_data * data,struct trace_buffer * buffer,void * rec,struct ring_buffer_event * event)1450 snapshot_count_trigger(struct event_trigger_data *data,
1451 		       struct trace_buffer *buffer, void *rec,
1452 		       struct ring_buffer_event *event)
1453 {
1454 	if (!data->count)
1455 		return;
1456 
1457 	if (data->count != -1)
1458 		(data->count)--;
1459 
1460 	snapshot_trigger(data, buffer, rec, event);
1461 }
1462 
1463 static int
register_snapshot_trigger(char * glob,struct event_trigger_data * data,struct trace_event_file * file)1464 register_snapshot_trigger(char *glob,
1465 			  struct event_trigger_data *data,
1466 			  struct trace_event_file *file)
1467 {
1468 	int ret = tracing_arm_snapshot(file->tr);
1469 
1470 	if (ret < 0)
1471 		return ret;
1472 
1473 	ret = register_trigger(glob, data, file);
1474 	if (ret < 0)
1475 		tracing_disarm_snapshot(file->tr);
1476 	return ret;
1477 }
1478 
unregister_snapshot_trigger(char * glob,struct event_trigger_data * data,struct trace_event_file * file)1479 static void unregister_snapshot_trigger(char *glob,
1480 					struct event_trigger_data *data,
1481 					struct trace_event_file *file)
1482 {
1483 	if (try_unregister_trigger(glob, data, file))
1484 		tracing_disarm_snapshot(file->tr);
1485 }
1486 
1487 static int
snapshot_trigger_print(struct seq_file * m,struct event_trigger_data * data)1488 snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1489 {
1490 	return event_trigger_print("snapshot", m, (void *)data->count,
1491 				   data->filter_str);
1492 }
1493 
1494 static struct event_trigger_ops snapshot_trigger_ops = {
1495 	.trigger		= snapshot_trigger,
1496 	.print			= snapshot_trigger_print,
1497 	.init			= event_trigger_init,
1498 	.free			= event_trigger_free,
1499 };
1500 
1501 static struct event_trigger_ops snapshot_count_trigger_ops = {
1502 	.trigger		= snapshot_count_trigger,
1503 	.print			= snapshot_trigger_print,
1504 	.init			= event_trigger_init,
1505 	.free			= event_trigger_free,
1506 };
1507 
1508 static struct event_trigger_ops *
snapshot_get_trigger_ops(char * cmd,char * param)1509 snapshot_get_trigger_ops(char *cmd, char *param)
1510 {
1511 	return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1512 }
1513 
1514 static struct event_command trigger_snapshot_cmd = {
1515 	.name			= "snapshot",
1516 	.trigger_type		= ETT_SNAPSHOT,
1517 	.parse			= event_trigger_parse,
1518 	.reg			= register_snapshot_trigger,
1519 	.unreg			= unregister_snapshot_trigger,
1520 	.get_trigger_ops	= snapshot_get_trigger_ops,
1521 	.set_filter		= set_trigger_filter,
1522 };
1523 
register_trigger_snapshot_cmd(void)1524 static __init int register_trigger_snapshot_cmd(void)
1525 {
1526 	int ret;
1527 
1528 	ret = register_event_command(&trigger_snapshot_cmd);
1529 	WARN_ON(ret < 0);
1530 
1531 	return ret;
1532 }
1533 #else
register_trigger_snapshot_cmd(void)1534 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1535 #endif /* CONFIG_TRACER_SNAPSHOT */
1536 
1537 #ifdef CONFIG_STACKTRACE
1538 #ifdef CONFIG_UNWINDER_ORC
1539 /* Skip 2:
1540  *   event_triggers_post_call()
1541  *   trace_event_raw_event_xxx()
1542  */
1543 # define STACK_SKIP 2
1544 #else
1545 /*
1546  * Skip 4:
1547  *   stacktrace_trigger()
1548  *   event_triggers_post_call()
1549  *   trace_event_buffer_commit()
1550  *   trace_event_raw_event_xxx()
1551  */
1552 #define STACK_SKIP 4
1553 #endif
1554 
1555 static void
stacktrace_trigger(struct event_trigger_data * data,struct trace_buffer * buffer,void * rec,struct ring_buffer_event * event)1556 stacktrace_trigger(struct event_trigger_data *data,
1557 		   struct trace_buffer *buffer,  void *rec,
1558 		   struct ring_buffer_event *event)
1559 {
1560 	struct trace_event_file *file = data->private_data;
1561 
1562 	if (file)
1563 		__trace_stack(file->tr, tracing_gen_ctx(), STACK_SKIP);
1564 	else
1565 		trace_dump_stack(STACK_SKIP);
1566 }
1567 
1568 static void
stacktrace_count_trigger(struct event_trigger_data * data,struct trace_buffer * buffer,void * rec,struct ring_buffer_event * event)1569 stacktrace_count_trigger(struct event_trigger_data *data,
1570 			 struct trace_buffer *buffer, void *rec,
1571 			 struct ring_buffer_event *event)
1572 {
1573 	if (!data->count)
1574 		return;
1575 
1576 	if (data->count != -1)
1577 		(data->count)--;
1578 
1579 	stacktrace_trigger(data, buffer, rec, event);
1580 }
1581 
1582 static int
stacktrace_trigger_print(struct seq_file * m,struct event_trigger_data * data)1583 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data)
1584 {
1585 	return event_trigger_print("stacktrace", m, (void *)data->count,
1586 				   data->filter_str);
1587 }
1588 
1589 static struct event_trigger_ops stacktrace_trigger_ops = {
1590 	.trigger		= stacktrace_trigger,
1591 	.print			= stacktrace_trigger_print,
1592 	.init			= event_trigger_init,
1593 	.free			= event_trigger_free,
1594 };
1595 
1596 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1597 	.trigger		= stacktrace_count_trigger,
1598 	.print			= stacktrace_trigger_print,
1599 	.init			= event_trigger_init,
1600 	.free			= event_trigger_free,
1601 };
1602 
1603 static struct event_trigger_ops *
stacktrace_get_trigger_ops(char * cmd,char * param)1604 stacktrace_get_trigger_ops(char *cmd, char *param)
1605 {
1606 	return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1607 }
1608 
1609 static struct event_command trigger_stacktrace_cmd = {
1610 	.name			= "stacktrace",
1611 	.trigger_type		= ETT_STACKTRACE,
1612 	.flags			= EVENT_CMD_FL_POST_TRIGGER,
1613 	.parse			= event_trigger_parse,
1614 	.reg			= register_trigger,
1615 	.unreg			= unregister_trigger,
1616 	.get_trigger_ops	= stacktrace_get_trigger_ops,
1617 	.set_filter		= set_trigger_filter,
1618 };
1619 
register_trigger_stacktrace_cmd(void)1620 static __init int register_trigger_stacktrace_cmd(void)
1621 {
1622 	int ret;
1623 
1624 	ret = register_event_command(&trigger_stacktrace_cmd);
1625 	WARN_ON(ret < 0);
1626 
1627 	return ret;
1628 }
1629 #else
register_trigger_stacktrace_cmd(void)1630 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1631 #endif /* CONFIG_STACKTRACE */
1632 
unregister_trigger_traceon_traceoff_cmds(void)1633 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1634 {
1635 	unregister_event_command(&trigger_traceon_cmd);
1636 	unregister_event_command(&trigger_traceoff_cmd);
1637 }
1638 
1639 static void
event_enable_trigger(struct event_trigger_data * data,struct trace_buffer * buffer,void * rec,struct ring_buffer_event * event)1640 event_enable_trigger(struct event_trigger_data *data,
1641 		     struct trace_buffer *buffer,  void *rec,
1642 		     struct ring_buffer_event *event)
1643 {
1644 	struct enable_trigger_data *enable_data = data->private_data;
1645 
1646 	if (enable_data->enable)
1647 		clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1648 	else
1649 		set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1650 }
1651 
1652 static void
event_enable_count_trigger(struct event_trigger_data * data,struct trace_buffer * buffer,void * rec,struct ring_buffer_event * event)1653 event_enable_count_trigger(struct event_trigger_data *data,
1654 			   struct trace_buffer *buffer,  void *rec,
1655 			   struct ring_buffer_event *event)
1656 {
1657 	struct enable_trigger_data *enable_data = data->private_data;
1658 
1659 	if (!data->count)
1660 		return;
1661 
1662 	/* Skip if the event is in a state we want to switch to */
1663 	if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1664 		return;
1665 
1666 	if (data->count != -1)
1667 		(data->count)--;
1668 
1669 	event_enable_trigger(data, buffer, rec, event);
1670 }
1671 
event_enable_trigger_print(struct seq_file * m,struct event_trigger_data * data)1672 int event_enable_trigger_print(struct seq_file *m,
1673 			       struct event_trigger_data *data)
1674 {
1675 	struct enable_trigger_data *enable_data = data->private_data;
1676 
1677 	seq_printf(m, "%s:%s:%s",
1678 		   enable_data->hist ?
1679 		   (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1680 		   (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1681 		   enable_data->file->event_call->class->system,
1682 		   trace_event_name(enable_data->file->event_call));
1683 
1684 	if (data->count == -1)
1685 		seq_puts(m, ":unlimited");
1686 	else
1687 		seq_printf(m, ":count=%ld", data->count);
1688 
1689 	if (data->filter_str)
1690 		seq_printf(m, " if %s\n", data->filter_str);
1691 	else
1692 		seq_putc(m, '\n');
1693 
1694 	return 0;
1695 }
1696 
event_enable_trigger_free(struct event_trigger_data * data)1697 void event_enable_trigger_free(struct event_trigger_data *data)
1698 {
1699 	struct enable_trigger_data *enable_data = data->private_data;
1700 
1701 	if (WARN_ON_ONCE(data->ref <= 0))
1702 		return;
1703 
1704 	data->ref--;
1705 	if (!data->ref) {
1706 		/* Remove the SOFT_MODE flag */
1707 		trace_event_enable_disable(enable_data->file, 0, 1);
1708 		trace_event_put_ref(enable_data->file->event_call);
1709 		trigger_data_free(data);
1710 		kfree(enable_data);
1711 	}
1712 }
1713 
1714 static struct event_trigger_ops event_enable_trigger_ops = {
1715 	.trigger		= event_enable_trigger,
1716 	.print			= event_enable_trigger_print,
1717 	.init			= event_trigger_init,
1718 	.free			= event_enable_trigger_free,
1719 };
1720 
1721 static struct event_trigger_ops event_enable_count_trigger_ops = {
1722 	.trigger		= event_enable_count_trigger,
1723 	.print			= event_enable_trigger_print,
1724 	.init			= event_trigger_init,
1725 	.free			= event_enable_trigger_free,
1726 };
1727 
1728 static struct event_trigger_ops event_disable_trigger_ops = {
1729 	.trigger		= event_enable_trigger,
1730 	.print			= event_enable_trigger_print,
1731 	.init			= event_trigger_init,
1732 	.free			= event_enable_trigger_free,
1733 };
1734 
1735 static struct event_trigger_ops event_disable_count_trigger_ops = {
1736 	.trigger		= event_enable_count_trigger,
1737 	.print			= event_enable_trigger_print,
1738 	.init			= event_trigger_init,
1739 	.free			= event_enable_trigger_free,
1740 };
1741 
event_enable_trigger_parse(struct event_command * cmd_ops,struct trace_event_file * file,char * glob,char * cmd,char * param_and_filter)1742 int event_enable_trigger_parse(struct event_command *cmd_ops,
1743 			       struct trace_event_file *file,
1744 			       char *glob, char *cmd, char *param_and_filter)
1745 {
1746 	struct trace_event_file *event_enable_file;
1747 	struct enable_trigger_data *enable_data;
1748 	struct event_trigger_data *trigger_data;
1749 	struct trace_array *tr = file->tr;
1750 	char *param, *filter;
1751 	bool enable, remove;
1752 	const char *system;
1753 	const char *event;
1754 	bool hist = false;
1755 	int ret;
1756 
1757 	remove = event_trigger_check_remove(glob);
1758 
1759 	if (event_trigger_empty_param(param_and_filter))
1760 		return -EINVAL;
1761 
1762 	ret = event_trigger_separate_filter(param_and_filter, &param, &filter, true);
1763 	if (ret)
1764 		return ret;
1765 
1766 	system = strsep(&param, ":");
1767 	if (!param)
1768 		return -EINVAL;
1769 
1770 	event = strsep(&param, ":");
1771 
1772 	ret = -EINVAL;
1773 	event_enable_file = find_event_file(tr, system, event);
1774 	if (!event_enable_file)
1775 		goto out;
1776 
1777 #ifdef CONFIG_HIST_TRIGGERS
1778 	hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1779 		(strcmp(cmd, DISABLE_HIST_STR) == 0));
1780 
1781 	enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1782 		  (strcmp(cmd, ENABLE_HIST_STR) == 0));
1783 #else
1784 	enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1785 #endif
1786 	ret = -ENOMEM;
1787 
1788 	enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1789 	if (!enable_data)
1790 		goto out;
1791 
1792 	enable_data->hist = hist;
1793 	enable_data->enable = enable;
1794 	enable_data->file = event_enable_file;
1795 
1796 	trigger_data = event_trigger_alloc(cmd_ops, cmd, param, enable_data);
1797 	if (!trigger_data) {
1798 		kfree(enable_data);
1799 		goto out;
1800 	}
1801 
1802 	if (remove) {
1803 		event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
1804 		kfree(trigger_data);
1805 		kfree(enable_data);
1806 		ret = 0;
1807 		goto out;
1808 	}
1809 
1810 	/* Up the trigger_data count to make sure nothing frees it on failure */
1811 	event_trigger_init(trigger_data);
1812 
1813 	ret = event_trigger_parse_num(param, trigger_data);
1814 	if (ret)
1815 		goto out_free;
1816 
1817 	ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
1818 	if (ret < 0)
1819 		goto out_free;
1820 
1821 	/* Don't let event modules unload while probe registered */
1822 	ret = trace_event_try_get_ref(event_enable_file->event_call);
1823 	if (!ret) {
1824 		ret = -EBUSY;
1825 		goto out_free;
1826 	}
1827 
1828 	ret = trace_event_enable_disable(event_enable_file, 1, 1);
1829 	if (ret < 0)
1830 		goto out_put;
1831 
1832 	ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
1833 	if (ret)
1834 		goto out_disable;
1835 
1836 	event_trigger_free(trigger_data);
1837  out:
1838 	return ret;
1839  out_disable:
1840 	trace_event_enable_disable(event_enable_file, 0, 1);
1841  out_put:
1842 	trace_event_put_ref(event_enable_file->event_call);
1843  out_free:
1844 	event_trigger_reset_filter(cmd_ops, trigger_data);
1845 	event_trigger_free(trigger_data);
1846 	kfree(enable_data);
1847 
1848 	goto out;
1849 }
1850 
event_enable_register_trigger(char * glob,struct event_trigger_data * data,struct trace_event_file * file)1851 int event_enable_register_trigger(char *glob,
1852 				  struct event_trigger_data *data,
1853 				  struct trace_event_file *file)
1854 {
1855 	struct enable_trigger_data *enable_data = data->private_data;
1856 	struct enable_trigger_data *test_enable_data;
1857 	struct event_trigger_data *test;
1858 	int ret = 0;
1859 
1860 	lockdep_assert_held(&event_mutex);
1861 
1862 	list_for_each_entry(test, &file->triggers, list) {
1863 		test_enable_data = test->private_data;
1864 		if (test_enable_data &&
1865 		    (test->cmd_ops->trigger_type ==
1866 		     data->cmd_ops->trigger_type) &&
1867 		    (test_enable_data->file == enable_data->file)) {
1868 			ret = -EEXIST;
1869 			goto out;
1870 		}
1871 	}
1872 
1873 	if (data->ops->init) {
1874 		ret = data->ops->init(data);
1875 		if (ret < 0)
1876 			goto out;
1877 	}
1878 
1879 	list_add_rcu(&data->list, &file->triggers);
1880 
1881 	update_cond_flag(file);
1882 	ret = trace_event_trigger_enable_disable(file, 1);
1883 	if (ret < 0) {
1884 		list_del_rcu(&data->list);
1885 		update_cond_flag(file);
1886 	}
1887 out:
1888 	return ret;
1889 }
1890 
event_enable_unregister_trigger(char * glob,struct event_trigger_data * test,struct trace_event_file * file)1891 void event_enable_unregister_trigger(char *glob,
1892 				     struct event_trigger_data *test,
1893 				     struct trace_event_file *file)
1894 {
1895 	struct enable_trigger_data *test_enable_data = test->private_data;
1896 	struct event_trigger_data *data = NULL, *iter;
1897 	struct enable_trigger_data *enable_data;
1898 
1899 	lockdep_assert_held(&event_mutex);
1900 
1901 	list_for_each_entry(iter, &file->triggers, list) {
1902 		enable_data = iter->private_data;
1903 		if (enable_data &&
1904 		    (iter->cmd_ops->trigger_type ==
1905 		     test->cmd_ops->trigger_type) &&
1906 		    (enable_data->file == test_enable_data->file)) {
1907 			data = iter;
1908 			list_del_rcu(&data->list);
1909 			trace_event_trigger_enable_disable(file, 0);
1910 			update_cond_flag(file);
1911 			break;
1912 		}
1913 	}
1914 
1915 	if (data && data->ops->free)
1916 		data->ops->free(data);
1917 }
1918 
1919 static struct event_trigger_ops *
event_enable_get_trigger_ops(char * cmd,char * param)1920 event_enable_get_trigger_ops(char *cmd, char *param)
1921 {
1922 	struct event_trigger_ops *ops;
1923 	bool enable;
1924 
1925 #ifdef CONFIG_HIST_TRIGGERS
1926 	enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1927 		  (strcmp(cmd, ENABLE_HIST_STR) == 0));
1928 #else
1929 	enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1930 #endif
1931 	if (enable)
1932 		ops = param ? &event_enable_count_trigger_ops :
1933 			&event_enable_trigger_ops;
1934 	else
1935 		ops = param ? &event_disable_count_trigger_ops :
1936 			&event_disable_trigger_ops;
1937 
1938 	return ops;
1939 }
1940 
1941 static struct event_command trigger_enable_cmd = {
1942 	.name			= ENABLE_EVENT_STR,
1943 	.trigger_type		= ETT_EVENT_ENABLE,
1944 	.parse			= event_enable_trigger_parse,
1945 	.reg			= event_enable_register_trigger,
1946 	.unreg			= event_enable_unregister_trigger,
1947 	.get_trigger_ops	= event_enable_get_trigger_ops,
1948 	.set_filter		= set_trigger_filter,
1949 };
1950 
1951 static struct event_command trigger_disable_cmd = {
1952 	.name			= DISABLE_EVENT_STR,
1953 	.trigger_type		= ETT_EVENT_ENABLE,
1954 	.parse			= event_enable_trigger_parse,
1955 	.reg			= event_enable_register_trigger,
1956 	.unreg			= event_enable_unregister_trigger,
1957 	.get_trigger_ops	= event_enable_get_trigger_ops,
1958 	.set_filter		= set_trigger_filter,
1959 };
1960 
unregister_trigger_enable_disable_cmds(void)1961 static __init void unregister_trigger_enable_disable_cmds(void)
1962 {
1963 	unregister_event_command(&trigger_enable_cmd);
1964 	unregister_event_command(&trigger_disable_cmd);
1965 }
1966 
register_trigger_enable_disable_cmds(void)1967 static __init int register_trigger_enable_disable_cmds(void)
1968 {
1969 	int ret;
1970 
1971 	ret = register_event_command(&trigger_enable_cmd);
1972 	if (WARN_ON(ret < 0))
1973 		return ret;
1974 	ret = register_event_command(&trigger_disable_cmd);
1975 	if (WARN_ON(ret < 0))
1976 		unregister_trigger_enable_disable_cmds();
1977 
1978 	return ret;
1979 }
1980 
register_trigger_traceon_traceoff_cmds(void)1981 static __init int register_trigger_traceon_traceoff_cmds(void)
1982 {
1983 	int ret;
1984 
1985 	ret = register_event_command(&trigger_traceon_cmd);
1986 	if (WARN_ON(ret < 0))
1987 		return ret;
1988 	ret = register_event_command(&trigger_traceoff_cmd);
1989 	if (WARN_ON(ret < 0))
1990 		unregister_trigger_traceon_traceoff_cmds();
1991 
1992 	return ret;
1993 }
1994 
register_trigger_cmds(void)1995 __init int register_trigger_cmds(void)
1996 {
1997 	register_trigger_traceon_traceoff_cmds();
1998 	register_trigger_snapshot_cmd();
1999 	register_trigger_stacktrace_cmd();
2000 	register_trigger_enable_disable_cmds();
2001 	register_trigger_hist_enable_disable_cmds();
2002 	register_trigger_hist_cmd();
2003 
2004 	return 0;
2005 }
2006