?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
workqueue: async worker destruction
[linux-2.6/btrfs-unstable.git] / kernel / trace / trace_events.c
blob3ddfd8f62c05f10864164e7ff79fcc3d6b450537
1 /*
2 * event tracer
3 *
4 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
5 *
6 * - Added format output of fields of the trace point.
7 * This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
8 *
9 */
10
11 #include <linux/workqueue.h>
12 #include <linux/spinlock.h>
13 #include <linux/kthread.h>
14 #include <linux/debugfs.h>
15 #include <linux/uaccess.h>
16 #include <linux/module.h>
17 #include <linux/ctype.h>
18 #include <linux/slab.h>
19 #include <linux/delay.h>
20
21 #include <asm/setup.h>
22
23 #include "trace_output.h"
24
25 #undef TRACE_SYSTEM
26 #define TRACE_SYSTEM "TRACE_SYSTEM"
27
28 DEFINE_MUTEX(event_mutex);
29
30 LIST_HEAD(ftrace_events);
31 static LIST_HEAD(ftrace_common_fields);
32
33 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
34
35 static struct kmem_cache *field_cachep;
36 static struct kmem_cache *file_cachep;
37
38 #define SYSTEM_FL_FREE_NAME (1 << 31)
39
40 static inline int system_refcount(struct event_subsystem *system)
41 {
42 return system->ref_count & ~SYSTEM_FL_FREE_NAME;
43 }
44
45 static int system_refcount_inc(struct event_subsystem *system)
46 {
47 return (system->ref_count++) & ~SYSTEM_FL_FREE_NAME;
48 }
49
50 static int system_refcount_dec(struct event_subsystem *system)
51 {
52 return (--system->ref_count) & ~SYSTEM_FL_FREE_NAME;
53 }
54
55 /* Double loops, do not use break, only goto's work */
56 #define do_for_each_event_file(tr, file) \
57 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
58 list_for_each_entry(file, &tr->events, list)
59
60 #define do_for_each_event_file_safe(tr, file) \
61 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
62 struct ftrace_event_file *___n; \
63 list_for_each_entry_safe(file, ___n, &tr->events, list)
64
65 #define while_for_each_event_file() \
66 }
67
68 static struct list_head *
69 trace_get_fields(struct ftrace_event_call *event_call)
70 {
71 if (!event_call->class->get_fields)
72 return &event_call->class->fields;
73 return event_call->class->get_fields(event_call);
74 }
75
76 static struct ftrace_event_field *
77 __find_event_field(struct list_head *head, char *name)
78 {
79 struct ftrace_event_field *field;
80
81 list_for_each_entry(field, head, link) {
82 if (!strcmp(field->name, name))
83 return field;
84 }
85
86 return NULL;
87 }
88
89 struct ftrace_event_field *
90 trace_find_event_field(struct ftrace_event_call *call, char *name)
91 {
92 struct ftrace_event_field *field;
93 struct list_head *head;
94
95 field = __find_event_field(&ftrace_common_fields, name);
96 if (field)
97 return field;
98
99 head = trace_get_fields(call);
100 return __find_event_field(head, name);
101 }
102
103 static int __trace_define_field(struct list_head *head, const char *type,
104 const char *name, int offset, int size,
105 int is_signed, int filter_type)
106 {
107 struct ftrace_event_field *field;
108
109 field = kmem_cache_alloc(field_cachep, GFP_TRACE);
110 if (!field)
111 return -ENOMEM;
112
113 field->name = name;
114 field->type = type;
115
116 if (filter_type == FILTER_OTHER)
117 field->filter_type = filter_assign_type(type);
118 else
119 field->filter_type = filter_type;
120
121 field->offset = offset;
122 field->size = size;
123 field->is_signed = is_signed;
124
125 list_add(&field->link, head);
126
127 return 0;
128 }
129
130 int trace_define_field(struct ftrace_event_call *call, const char *type,
131 const char *name, int offset, int size, int is_signed,
132 int filter_type)
133 {
134 struct list_head *head;
135
136 if (WARN_ON(!call->class))
137 return 0;
138
139 head = trace_get_fields(call);
140 return __trace_define_field(head, type, name, offset, size,
141 is_signed, filter_type);
142 }
143 EXPORT_SYMBOL_GPL(trace_define_field);
144
145 #define __common_field(type, item) \
146 ret = __trace_define_field(&ftrace_common_fields, #type, \
147 "common_" #item, \
148 offsetof(typeof(ent), item), \
149 sizeof(ent.item), \
150 is_signed_type(type), FILTER_OTHER); \
151 if (ret) \
152 return ret;
153
154 static int trace_define_common_fields(void)
155 {
156 int ret;
157 struct trace_entry ent;
158
159 __common_field(unsigned short, type);
160 __common_field(unsigned char, flags);
161 __common_field(unsigned char, preempt_count);
162 __common_field(int, pid);
163
164 return ret;
165 }
166
167 static void trace_destroy_fields(struct ftrace_event_call *call)
168 {
169 struct ftrace_event_field *field, *next;
170 struct list_head *head;
171
172 head = trace_get_fields(call);
173 list_for_each_entry_safe(field, next, head, link) {
174 list_del(&field->link);
175 kmem_cache_free(field_cachep, field);
176 }
177 }
178
179 int trace_event_raw_init(struct ftrace_event_call *call)
180 {
181 int id;
182
183 id = register_ftrace_event(&call->event);
184 if (!id)
185 return -ENODEV;
186
187 return 0;
188 }
189 EXPORT_SYMBOL_GPL(trace_event_raw_init);
190
191 void *ftrace_event_buffer_reserve(struct ftrace_event_buffer *fbuffer,
192 struct ftrace_event_file *ftrace_file,
193 unsigned long len)
194 {
195 struct ftrace_event_call *event_call = ftrace_file->event_call;
196
197 local_save_flags(fbuffer->flags);
198 fbuffer->pc = preempt_count();
199 fbuffer->ftrace_file = ftrace_file;
200
201 fbuffer->event =
202 trace_event_buffer_lock_reserve(&fbuffer->buffer, ftrace_file,
203 event_call->event.type, len,
204 fbuffer->flags, fbuffer->pc);
205 if (!fbuffer->event)
206 return NULL;
207
208 fbuffer->entry = ring_buffer_event_data(fbuffer->event);
209 return fbuffer->entry;
210 }
211 EXPORT_SYMBOL_GPL(ftrace_event_buffer_reserve);
212
213 void ftrace_event_buffer_commit(struct ftrace_event_buffer *fbuffer)
214 {
215 event_trigger_unlock_commit(fbuffer->ftrace_file, fbuffer->buffer,
216 fbuffer->event, fbuffer->entry,
217 fbuffer->flags, fbuffer->pc);
218 }
219 EXPORT_SYMBOL_GPL(ftrace_event_buffer_commit);
220
221 int ftrace_event_reg(struct ftrace_event_call *call,
222 enum trace_reg type, void *data)
223 {
224 struct ftrace_event_file *file = data;
225
226 WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
227 switch (type) {
228 case TRACE_REG_REGISTER:
229 return tracepoint_probe_register(call->tp,
230 call->class->probe,
231 file);
232 case TRACE_REG_UNREGISTER:
233 tracepoint_probe_unregister(call->tp,
234 call->class->probe,
235 file);
236 return 0;
237
238 #ifdef CONFIG_PERF_EVENTS
239 case TRACE_REG_PERF_REGISTER:
240 return tracepoint_probe_register(call->tp,
241 call->class->perf_probe,
242 call);
243 case TRACE_REG_PERF_UNREGISTER:
244 tracepoint_probe_unregister(call->tp,
245 call->class->perf_probe,
246 call);
247 return 0;
248 case TRACE_REG_PERF_OPEN:
249 case TRACE_REG_PERF_CLOSE:
250 case TRACE_REG_PERF_ADD:
251 case TRACE_REG_PERF_DEL:
252 return 0;
253 #endif
254 }
255 return 0;
256 }
257 EXPORT_SYMBOL_GPL(ftrace_event_reg);
258
259 void trace_event_enable_cmd_record(bool enable)
260 {
261 struct ftrace_event_file *file;
262 struct trace_array *tr;
263
264 mutex_lock(&event_mutex);
265 do_for_each_event_file(tr, file) {
266
267 if (!(file->flags & FTRACE_EVENT_FL_ENABLED))
268 continue;
269
270 if (enable) {
271 tracing_start_cmdline_record();
272 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
273 } else {
274 tracing_stop_cmdline_record();
275 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
276 }
277 } while_for_each_event_file();
278 mutex_unlock(&event_mutex);
279 }
280
281 static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
282 int enable, int soft_disable)
283 {
284 struct ftrace_event_call *call = file->event_call;
285 int ret = 0;
286 int disable;
287
288 switch (enable) {
289 case 0:
290 /*
291 * When soft_disable is set and enable is cleared, the sm_ref
292 * reference counter is decremented. If it reaches 0, we want
293 * to clear the SOFT_DISABLED flag but leave the event in the
294 * state that it was. That is, if the event was enabled and
295 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
296 * is set we do not want the event to be enabled before we
297 * clear the bit.
298 *
299 * When soft_disable is not set but the SOFT_MODE flag is,
300 * we do nothing. Do not disable the tracepoint, otherwise
301 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
302 */
303 if (soft_disable) {
304 if (atomic_dec_return(&file->sm_ref) > 0)
305 break;
306 disable = file->flags & FTRACE_EVENT_FL_SOFT_DISABLED;
307 clear_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
308 } else
309 disable = !(file->flags & FTRACE_EVENT_FL_SOFT_MODE);
310
311 if (disable && (file->flags & FTRACE_EVENT_FL_ENABLED)) {
312 clear_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
313 if (file->flags & FTRACE_EVENT_FL_RECORDED_CMD) {
314 tracing_stop_cmdline_record();
315 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
316 }
317 call->class->reg(call, TRACE_REG_UNREGISTER, file);
318 }
319 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
320 if (file->flags & FTRACE_EVENT_FL_SOFT_MODE)
321 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
322 else
323 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
324 break;
325 case 1:
326 /*
327 * When soft_disable is set and enable is set, we want to
328 * register the tracepoint for the event, but leave the event
329 * as is. That means, if the event was already enabled, we do
330 * nothing (but set SOFT_MODE). If the event is disabled, we
331 * set SOFT_DISABLED before enabling the event tracepoint, so
332 * it still seems to be disabled.
333 */
334 if (!soft_disable)
335 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
336 else {
337 if (atomic_inc_return(&file->sm_ref) > 1)
338 break;
339 set_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
340 }
341
342 if (!(file->flags & FTRACE_EVENT_FL_ENABLED)) {
343
344 /* Keep the event disabled, when going to SOFT_MODE. */
345 if (soft_disable)
346 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
347
348 if (trace_flags & TRACE_ITER_RECORD_CMD) {
349 tracing_start_cmdline_record();
350 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
351 }
352 ret = call->class->reg(call, TRACE_REG_REGISTER, file);
353 if (ret) {
354 tracing_stop_cmdline_record();
355 pr_info("event trace: Could not enable event "
356 "%s\n", ftrace_event_name(call));
357 break;
358 }
359 set_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
360
361 /* WAS_ENABLED gets set but never cleared. */
362 call->flags |= TRACE_EVENT_FL_WAS_ENABLED;
363 }
364 break;
365 }
366
367 return ret;
368 }
369
370 int trace_event_enable_disable(struct ftrace_event_file *file,
371 int enable, int soft_disable)
372 {
373 return __ftrace_event_enable_disable(file, enable, soft_disable);
374 }
375
376 static int ftrace_event_enable_disable(struct ftrace_event_file *file,
377 int enable)
378 {
379 return __ftrace_event_enable_disable(file, enable, 0);
380 }
381
382 static void ftrace_clear_events(struct trace_array *tr)
383 {
384 struct ftrace_event_file *file;
385
386 mutex_lock(&event_mutex);
387 list_for_each_entry(file, &tr->events, list) {
388 ftrace_event_enable_disable(file, 0);
389 }
390 mutex_unlock(&event_mutex);
391 }
392
393 static void __put_system(struct event_subsystem *system)
394 {
395 struct event_filter *filter = system->filter;
396
397 WARN_ON_ONCE(system_refcount(system) == 0);
398 if (system_refcount_dec(system))
399 return;
400
401 list_del(&system->list);
402
403 if (filter) {
404 kfree(filter->filter_string);
405 kfree(filter);
406 }
407 if (system->ref_count & SYSTEM_FL_FREE_NAME)
408 kfree(system->name);
409 kfree(system);
410 }
411
412 static void __get_system(struct event_subsystem *system)
413 {
414 WARN_ON_ONCE(system_refcount(system) == 0);
415 system_refcount_inc(system);
416 }
417
418 static void __get_system_dir(struct ftrace_subsystem_dir *dir)
419 {
420 WARN_ON_ONCE(dir->ref_count == 0);
421 dir->ref_count++;
422 __get_system(dir->subsystem);
423 }
424
425 static void __put_system_dir(struct ftrace_subsystem_dir *dir)
426 {
427 WARN_ON_ONCE(dir->ref_count == 0);
428 /* If the subsystem is about to be freed, the dir must be too */
429 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
430
431 __put_system(dir->subsystem);
432 if (!--dir->ref_count)
433 kfree(dir);
434 }
435
436 static void put_system(struct ftrace_subsystem_dir *dir)
437 {
438 mutex_lock(&event_mutex);
439 __put_system_dir(dir);
440 mutex_unlock(&event_mutex);
441 }
442
443 static void remove_subsystem(struct ftrace_subsystem_dir *dir)
444 {
445 if (!dir)
446 return;
447
448 if (!--dir->nr_events) {
449 debugfs_remove_recursive(dir->entry);
450 list_del(&dir->list);
451 __put_system_dir(dir);
452 }
453 }
454
455 static void remove_event_file_dir(struct ftrace_event_file *file)
456 {
457 struct dentry *dir = file->dir;
458 struct dentry *child;
459
460 if (dir) {
461 spin_lock(&dir->d_lock); /* probably unneeded */
462 list_for_each_entry(child, &dir->d_subdirs, d_u.d_child) {
463 if (child->d_inode) /* probably unneeded */
464 child->d_inode->i_private = NULL;
465 }
466 spin_unlock(&dir->d_lock);
467
468 debugfs_remove_recursive(dir);
469 }
470
471 list_del(&file->list);
472 remove_subsystem(file->system);
473 kmem_cache_free(file_cachep, file);
474 }
475
476 /*
477 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
478 */
479 static int
480 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
481 const char *sub, const char *event, int set)
482 {
483 struct ftrace_event_file *file;
484 struct ftrace_event_call *call;
485 const char *name;
486 int ret = -EINVAL;
487
488 list_for_each_entry(file, &tr->events, list) {
489
490 call = file->event_call;
491 name = ftrace_event_name(call);
492
493 if (!name || !call->class || !call->class->reg)
494 continue;
495
496 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
497 continue;
498
499 if (match &&
500 strcmp(match, name) != 0 &&
501 strcmp(match, call->class->system) != 0)
502 continue;
503
504 if (sub && strcmp(sub, call->class->system) != 0)
505 continue;
506
507 if (event && strcmp(event, name) != 0)
508 continue;
509
510 ftrace_event_enable_disable(file, set);
511
512 ret = 0;
513 }
514
515 return ret;
516 }
517
518 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
519 const char *sub, const char *event, int set)
520 {
521 int ret;
522
523 mutex_lock(&event_mutex);
524 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
525 mutex_unlock(&event_mutex);
526
527 return ret;
528 }
529
530 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
531 {
532 char *event = NULL, *sub = NULL, *match;
533
534 /*
535 * The buf format can be <subsystem>:<event-name>
536 * *:<event-name> means any event by that name.
537 * :<event-name> is the same.
538 *
539 * <subsystem>:* means all events in that subsystem
540 * <subsystem>: means the same.
541 *
542 * <name> (no ':') means all events in a subsystem with
543 * the name <name> or any event that matches <name>
544 */
545
546 match = strsep(&buf, ":");
547 if (buf) {
548 sub = match;
549 event = buf;
550 match = NULL;
551
552 if (!strlen(sub) || strcmp(sub, "*") == 0)
553 sub = NULL;
554 if (!strlen(event) || strcmp(event, "*") == 0)
555 event = NULL;
556 }
557
558 return __ftrace_set_clr_event(tr, match, sub, event, set);
559 }
560
561 /**
562 * trace_set_clr_event - enable or disable an event
563 * @system: system name to match (NULL for any system)
564 * @event: event name to match (NULL for all events, within system)
565 * @set: 1 to enable, 0 to disable
566 *
567 * This is a way for other parts of the kernel to enable or disable
568 * event recording.
569 *
570 * Returns 0 on success, -EINVAL if the parameters do not match any
571 * registered events.
572 */
573 int trace_set_clr_event(const char *system, const char *event, int set)
574 {
575 struct trace_array *tr = top_trace_array();
576
577 return __ftrace_set_clr_event(tr, NULL, system, event, set);
578 }
579 EXPORT_SYMBOL_GPL(trace_set_clr_event);
580
581 /* 128 should be much more than enough */
582 #define EVENT_BUF_SIZE 127
583
584 static ssize_t
585 ftrace_event_write(struct file *file, const char __user *ubuf,
586 size_t cnt, loff_t *ppos)
587 {
588 struct trace_parser parser;
589 struct seq_file *m = file->private_data;
590 struct trace_array *tr = m->private;
591 ssize_t read, ret;
592
593 if (!cnt)
594 return 0;
595
596 ret = tracing_update_buffers();
597 if (ret < 0)
598 return ret;
599
600 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
601 return -ENOMEM;
602
603 read = trace_get_user(&parser, ubuf, cnt, ppos);
604
605 if (read >= 0 && trace_parser_loaded((&parser))) {
606 int set = 1;
607
608 if (*parser.buffer == '!')
609 set = 0;
610
611 parser.buffer[parser.idx] = 0;
612
613 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
614 if (ret)
615 goto out_put;
616 }
617
618 ret = read;
619
620 out_put:
621 trace_parser_put(&parser);
622
623 return ret;
624 }
625
626 static void *
627 t_next(struct seq_file *m, void *v, loff_t *pos)
628 {
629 struct ftrace_event_file *file = v;
630 struct ftrace_event_call *call;
631 struct trace_array *tr = m->private;
632
633 (*pos)++;
634
635 list_for_each_entry_continue(file, &tr->events, list) {
636 call = file->event_call;
637 /*
638 * The ftrace subsystem is for showing formats only.
639 * They can not be enabled or disabled via the event files.
640 */
641 if (call->class && call->class->reg)
642 return file;
643 }
644
645 return NULL;
646 }
647
648 static void *t_start(struct seq_file *m, loff_t *pos)
649 {
650 struct ftrace_event_file *file;
651 struct trace_array *tr = m->private;
652 loff_t l;
653
654 mutex_lock(&event_mutex);
655
656 file = list_entry(&tr->events, struct ftrace_event_file, list);
657 for (l = 0; l <= *pos; ) {
658 file = t_next(m, file, &l);
659 if (!file)
660 break;
661 }
662 return file;
663 }
664
665 static void *
666 s_next(struct seq_file *m, void *v, loff_t *pos)
667 {
668 struct ftrace_event_file *file = v;
669 struct trace_array *tr = m->private;
670
671 (*pos)++;
672
673 list_for_each_entry_continue(file, &tr->events, list) {
674 if (file->flags & FTRACE_EVENT_FL_ENABLED)
675 return file;
676 }
677
678 return NULL;
679 }
680
681 static void *s_start(struct seq_file *m, loff_t *pos)
682 {
683 struct ftrace_event_file *file;
684 struct trace_array *tr = m->private;
685 loff_t l;
686
687 mutex_lock(&event_mutex);
688
689 file = list_entry(&tr->events, struct ftrace_event_file, list);
690 for (l = 0; l <= *pos; ) {
691 file = s_next(m, file, &l);
692 if (!file)
693 break;
694 }
695 return file;
696 }
697
698 static int t_show(struct seq_file *m, void *v)
699 {
700 struct ftrace_event_file *file = v;
701 struct ftrace_event_call *call = file->event_call;
702
703 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
704 seq_printf(m, "%s:", call->class->system);
705 seq_printf(m, "%s\n", ftrace_event_name(call));
706
707 return 0;
708 }
709
710 static void t_stop(struct seq_file *m, void *p)
711 {
712 mutex_unlock(&event_mutex);
713 }
714
715 static ssize_t
716 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
717 loff_t *ppos)
718 {
719 struct ftrace_event_file *file;
720 unsigned long flags;
721 char buf[4] = "0";
722
723 mutex_lock(&event_mutex);
724 file = event_file_data(filp);
725 if (likely(file))
726 flags = file->flags;
727 mutex_unlock(&event_mutex);
728
729 if (!file)
730 return -ENODEV;
731
732 if (flags & FTRACE_EVENT_FL_ENABLED &&
733 !(flags & FTRACE_EVENT_FL_SOFT_DISABLED))
734 strcpy(buf, "1");
735
736 if (flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
737 flags & FTRACE_EVENT_FL_SOFT_MODE)
738 strcat(buf, "*");
739
740 strcat(buf, "\n");
741
742 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
743 }
744
745 static ssize_t
746 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
747 loff_t *ppos)
748 {
749 struct ftrace_event_file *file;
750 unsigned long val;
751 int ret;
752
753 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
754 if (ret)
755 return ret;
756
757 ret = tracing_update_buffers();
758 if (ret < 0)
759 return ret;
760
761 switch (val) {
762 case 0:
763 case 1:
764 ret = -ENODEV;
765 mutex_lock(&event_mutex);
766 file = event_file_data(filp);
767 if (likely(file))
768 ret = ftrace_event_enable_disable(file, val);
769 mutex_unlock(&event_mutex);
770 break;
771
772 default:
773 return -EINVAL;
774 }
775
776 *ppos += cnt;
777
778 return ret ? ret : cnt;
779 }
780
781 static ssize_t
782 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
783 loff_t *ppos)
784 {
785 const char set_to_char[4] = { '?', '0', '1', 'X' };
786 struct ftrace_subsystem_dir *dir = filp->private_data;
787 struct event_subsystem *system = dir->subsystem;
788 struct ftrace_event_call *call;
789 struct ftrace_event_file *file;
790 struct trace_array *tr = dir->tr;
791 char buf[2];
792 int set = 0;
793 int ret;
794
795 mutex_lock(&event_mutex);
796 list_for_each_entry(file, &tr->events, list) {
797 call = file->event_call;
798 if (!ftrace_event_name(call) || !call->class || !call->class->reg)
799 continue;
800
801 if (system && strcmp(call->class->system, system->name) != 0)
802 continue;
803
804 /*
805 * We need to find out if all the events are set
806 * or if all events or cleared, or if we have
807 * a mixture.
808 */
809 set |= (1 << !!(file->flags & FTRACE_EVENT_FL_ENABLED));
810
811 /*
812 * If we have a mixture, no need to look further.
813 */
814 if (set == 3)
815 break;
816 }
817 mutex_unlock(&event_mutex);
818
819 buf[0] = set_to_char[set];
820 buf[1] = '\n';
821
822 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
823
824 return ret;
825 }
826
827 static ssize_t
828 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
829 loff_t *ppos)
830 {
831 struct ftrace_subsystem_dir *dir = filp->private_data;
832 struct event_subsystem *system = dir->subsystem;
833 const char *name = NULL;
834 unsigned long val;
835 ssize_t ret;
836
837 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
838 if (ret)
839 return ret;
840
841 ret = tracing_update_buffers();
842 if (ret < 0)
843 return ret;
844
845 if (val != 0 && val != 1)
846 return -EINVAL;
847
848 /*
849 * Opening of "enable" adds a ref count to system,
850 * so the name is safe to use.
851 */
852 if (system)
853 name = system->name;
854
855 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
856 if (ret)
857 goto out;
858
859 ret = cnt;
860
861 out:
862 *ppos += cnt;
863
864 return ret;
865 }
866
867 enum {
868 FORMAT_HEADER = 1,
869 FORMAT_FIELD_SEPERATOR = 2,
870 FORMAT_PRINTFMT = 3,
871 };
872
873 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
874 {
875 struct ftrace_event_call *call = event_file_data(m->private);
876 struct list_head *common_head = &ftrace_common_fields;
877 struct list_head *head = trace_get_fields(call);
878 struct list_head *node = v;
879
880 (*pos)++;
881
882 switch ((unsigned long)v) {
883 case FORMAT_HEADER:
884 node = common_head;
885 break;
886
887 case FORMAT_FIELD_SEPERATOR:
888 node = head;
889 break;
890
891 case FORMAT_PRINTFMT:
892 /* all done */
893 return NULL;
894 }
895
896 node = node->prev;
897 if (node == common_head)
898 return (void *)FORMAT_FIELD_SEPERATOR;
899 else if (node == head)
900 return (void *)FORMAT_PRINTFMT;
901 else
902 return node;
903 }
904
905 static int f_show(struct seq_file *m, void *v)
906 {
907 struct ftrace_event_call *call = event_file_data(m->private);
908 struct ftrace_event_field *field;
909 const char *array_descriptor;
910
911 switch ((unsigned long)v) {
912 case FORMAT_HEADER:
913 seq_printf(m, "name: %s\n", ftrace_event_name(call));
914 seq_printf(m, "ID: %d\n", call->event.type);
915 seq_printf(m, "format:\n");
916 return 0;
917
918 case FORMAT_FIELD_SEPERATOR:
919 seq_putc(m, '\n');
920 return 0;
921
922 case FORMAT_PRINTFMT:
923 seq_printf(m, "\nprint fmt: %s\n",
924 call->print_fmt);
925 return 0;
926 }
927
928 field = list_entry(v, struct ftrace_event_field, link);
929 /*
930 * Smartly shows the array type(except dynamic array).
931 * Normal:
932 * field:TYPE VAR
933 * If TYPE := TYPE[LEN], it is shown:
934 * field:TYPE VAR[LEN]
935 */
936 array_descriptor = strchr(field->type, '[');
937
938 if (!strncmp(field->type, "__data_loc", 10))
939 array_descriptor = NULL;
940
941 if (!array_descriptor)
942 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
943 field->type, field->name, field->offset,
944 field->size, !!field->is_signed);
945 else
946 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
947 (int)(array_descriptor - field->type),
948 field->type, field->name,
949 array_descriptor, field->offset,
950 field->size, !!field->is_signed);
951
952 return 0;
953 }
954
955 static void *f_start(struct seq_file *m, loff_t *pos)
956 {
957 void *p = (void *)FORMAT_HEADER;
958 loff_t l = 0;
959
960 /* ->stop() is called even if ->start() fails */
961 mutex_lock(&event_mutex);
962 if (!event_file_data(m->private))
963 return ERR_PTR(-ENODEV);
964
965 while (l < *pos && p)
966 p = f_next(m, p, &l);
967
968 return p;
969 }
970
971 static void f_stop(struct seq_file *m, void *p)
972 {
973 mutex_unlock(&event_mutex);
974 }
975
976 static const struct seq_operations trace_format_seq_ops = {
977 .start = f_start,
978 .next = f_next,
979 .stop = f_stop,
980 .show = f_show,
981 };
982
983 static int trace_format_open(struct inode *inode, struct file *file)
984 {
985 struct seq_file *m;
986 int ret;
987
988 ret = seq_open(file, &trace_format_seq_ops);
989 if (ret < 0)
990 return ret;
991
992 m = file->private_data;
993 m->private = file;
994
995 return 0;
996 }
997
998 static ssize_t
999 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1000 {
1001 int id = (long)event_file_data(filp);
1002 char buf[32];
1003 int len;
1004
1005 if (*ppos)
1006 return 0;
1007
1008 if (unlikely(!id))
1009 return -ENODEV;
1010
1011 len = sprintf(buf, "%d\n", id);
1012
1013 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1014 }
1015
1016 static ssize_t
1017 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1018 loff_t *ppos)
1019 {
1020 struct ftrace_event_file *file;
1021 struct trace_seq *s;
1022 int r = -ENODEV;
1023
1024 if (*ppos)
1025 return 0;
1026
1027 s = kmalloc(sizeof(*s), GFP_KERNEL);
1028
1029 if (!s)
1030 return -ENOMEM;
1031
1032 trace_seq_init(s);
1033
1034 mutex_lock(&event_mutex);
1035 file = event_file_data(filp);
1036 if (file)
1037 print_event_filter(file, s);
1038 mutex_unlock(&event_mutex);
1039
1040 if (file)
1041 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1042
1043 kfree(s);
1044
1045 return r;
1046 }
1047
1048 static ssize_t
1049 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1050 loff_t *ppos)
1051 {
1052 struct ftrace_event_file *file;
1053 char *buf;
1054 int err = -ENODEV;
1055
1056 if (cnt >= PAGE_SIZE)
1057 return -EINVAL;
1058
1059 buf = (char *)__get_free_page(GFP_TEMPORARY);
1060 if (!buf)
1061 return -ENOMEM;
1062
1063 if (copy_from_user(buf, ubuf, cnt)) {
1064 free_page((unsigned long) buf);
1065 return -EFAULT;
1066 }
1067 buf[cnt] = '\0';
1068
1069 mutex_lock(&event_mutex);
1070 file = event_file_data(filp);
1071 if (file)
1072 err = apply_event_filter(file, buf);
1073 mutex_unlock(&event_mutex);
1074
1075 free_page((unsigned long) buf);
1076 if (err < 0)
1077 return err;
1078
1079 *ppos += cnt;
1080
1081 return cnt;
1082 }
1083
1084 static LIST_HEAD(event_subsystems);
1085
1086 static int subsystem_open(struct inode *inode, struct file *filp)
1087 {
1088 struct event_subsystem *system = NULL;
1089 struct ftrace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1090 struct trace_array *tr;
1091 int ret;
1092
1093 if (tracing_is_disabled())
1094 return -ENODEV;
1095
1096 /* Make sure the system still exists */
1097 mutex_lock(&trace_types_lock);
1098 mutex_lock(&event_mutex);
1099 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1100 list_for_each_entry(dir, &tr->systems, list) {
1101 if (dir == inode->i_private) {
1102 /* Don't open systems with no events */
1103 if (dir->nr_events) {
1104 __get_system_dir(dir);
1105 system = dir->subsystem;
1106 }
1107 goto exit_loop;
1108 }
1109 }
1110 }
1111 exit_loop:
1112 mutex_unlock(&event_mutex);
1113 mutex_unlock(&trace_types_lock);
1114
1115 if (!system)
1116 return -ENODEV;
1117
1118 /* Some versions of gcc think dir can be uninitialized here */
1119 WARN_ON(!dir);
1120
1121 /* Still need to increment the ref count of the system */
1122 if (trace_array_get(tr) < 0) {
1123 put_system(dir);
1124 return -ENODEV;
1125 }
1126
1127 ret = tracing_open_generic(inode, filp);
1128 if (ret < 0) {
1129 trace_array_put(tr);
1130 put_system(dir);
1131 }
1132
1133 return ret;
1134 }
1135
1136 static int system_tr_open(struct inode *inode, struct file *filp)
1137 {
1138 struct ftrace_subsystem_dir *dir;
1139 struct trace_array *tr = inode->i_private;
1140 int ret;
1141
1142 if (tracing_is_disabled())
1143 return -ENODEV;
1144
1145 if (trace_array_get(tr) < 0)
1146 return -ENODEV;
1147
1148 /* Make a temporary dir that has no system but points to tr */
1149 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1150 if (!dir) {
1151 trace_array_put(tr);
1152 return -ENOMEM;
1153 }
1154
1155 dir->tr = tr;
1156
1157 ret = tracing_open_generic(inode, filp);
1158 if (ret < 0) {
1159 trace_array_put(tr);
1160 kfree(dir);
1161 return ret;
1162 }
1163
1164 filp->private_data = dir;
1165
1166 return 0;
1167 }
1168
1169 static int subsystem_release(struct inode *inode, struct file *file)
1170 {
1171 struct ftrace_subsystem_dir *dir = file->private_data;
1172
1173 trace_array_put(dir->tr);
1174
1175 /*
1176 * If dir->subsystem is NULL, then this is a temporary
1177 * descriptor that was made for a trace_array to enable
1178 * all subsystems.
1179 */
1180 if (dir->subsystem)
1181 put_system(dir);
1182 else
1183 kfree(dir);
1184
1185 return 0;
1186 }
1187
1188 static ssize_t
1189 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1190 loff_t *ppos)
1191 {
1192 struct ftrace_subsystem_dir *dir = filp->private_data;
1193 struct event_subsystem *system = dir->subsystem;
1194 struct trace_seq *s;
1195 int r;
1196
1197 if (*ppos)
1198 return 0;
1199
1200 s = kmalloc(sizeof(*s), GFP_KERNEL);
1201 if (!s)
1202 return -ENOMEM;
1203
1204 trace_seq_init(s);
1205
1206 print_subsystem_event_filter(system, s);
1207 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1208
1209 kfree(s);
1210
1211 return r;
1212 }
1213
1214 static ssize_t
1215 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1216 loff_t *ppos)
1217 {
1218 struct ftrace_subsystem_dir *dir = filp->private_data;
1219 char *buf;
1220 int err;
1221
1222 if (cnt >= PAGE_SIZE)
1223 return -EINVAL;
1224
1225 buf = (char *)__get_free_page(GFP_TEMPORARY);
1226 if (!buf)
1227 return -ENOMEM;
1228
1229 if (copy_from_user(buf, ubuf, cnt)) {
1230 free_page((unsigned long) buf);
1231 return -EFAULT;
1232 }
1233 buf[cnt] = '\0';
1234
1235 err = apply_subsystem_event_filter(dir, buf);
1236 free_page((unsigned long) buf);
1237 if (err < 0)
1238 return err;
1239
1240 *ppos += cnt;
1241
1242 return cnt;
1243 }
1244
1245 static ssize_t
1246 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1247 {
1248 int (*func)(struct trace_seq *s) = filp->private_data;
1249 struct trace_seq *s;
1250 int r;
1251
1252 if (*ppos)
1253 return 0;
1254
1255 s = kmalloc(sizeof(*s), GFP_KERNEL);
1256 if (!s)
1257 return -ENOMEM;
1258
1259 trace_seq_init(s);
1260
1261 func(s);
1262 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1263
1264 kfree(s);
1265
1266 return r;
1267 }
1268
1269 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1270 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1271 static int ftrace_event_release(struct inode *inode, struct file *file);
1272
1273 static const struct seq_operations show_event_seq_ops = {
1274 .start = t_start,
1275 .next = t_next,
1276 .show = t_show,
1277 .stop = t_stop,
1278 };
1279
1280 static const struct seq_operations show_set_event_seq_ops = {
1281 .start = s_start,
1282 .next = s_next,
1283 .show = t_show,
1284 .stop = t_stop,
1285 };
1286
1287 static const struct file_operations ftrace_avail_fops = {
1288 .open = ftrace_event_avail_open,
1289 .read = seq_read,
1290 .llseek = seq_lseek,
1291 .release = seq_release,
1292 };
1293
1294 static const struct file_operations ftrace_set_event_fops = {
1295 .open = ftrace_event_set_open,
1296 .read = seq_read,
1297 .write = ftrace_event_write,
1298 .llseek = seq_lseek,
1299 .release = ftrace_event_release,
1300 };
1301
1302 static const struct file_operations ftrace_enable_fops = {
1303 .open = tracing_open_generic,
1304 .read = event_enable_read,
1305 .write = event_enable_write,
1306 .llseek = default_llseek,
1307 };
1308
1309 static const struct file_operations ftrace_event_format_fops = {
1310 .open = trace_format_open,
1311 .read = seq_read,
1312 .llseek = seq_lseek,
1313 .release = seq_release,
1314 };
1315
1316 static const struct file_operations ftrace_event_id_fops = {
1317 .read = event_id_read,
1318 .llseek = default_llseek,
1319 };
1320
1321 static const struct file_operations ftrace_event_filter_fops = {
1322 .open = tracing_open_generic,
1323 .read = event_filter_read,
1324 .write = event_filter_write,
1325 .llseek = default_llseek,
1326 };
1327
1328 static const struct file_operations ftrace_subsystem_filter_fops = {
1329 .open = subsystem_open,
1330 .read = subsystem_filter_read,
1331 .write = subsystem_filter_write,
1332 .llseek = default_llseek,
1333 .release = subsystem_release,
1334 };
1335
1336 static const struct file_operations ftrace_system_enable_fops = {
1337 .open = subsystem_open,
1338 .read = system_enable_read,
1339 .write = system_enable_write,
1340 .llseek = default_llseek,
1341 .release = subsystem_release,
1342 };
1343
1344 static const struct file_operations ftrace_tr_enable_fops = {
1345 .open = system_tr_open,
1346 .read = system_enable_read,
1347 .write = system_enable_write,
1348 .llseek = default_llseek,
1349 .release = subsystem_release,
1350 };
1351
1352 static const struct file_operations ftrace_show_header_fops = {
1353 .open = tracing_open_generic,
1354 .read = show_header,
1355 .llseek = default_llseek,
1356 };
1357
1358 static int
1359 ftrace_event_open(struct inode *inode, struct file *file,
1360 const struct seq_operations *seq_ops)
1361 {
1362 struct seq_file *m;
1363 int ret;
1364
1365 ret = seq_open(file, seq_ops);
1366 if (ret < 0)
1367 return ret;
1368 m = file->private_data;
1369 /* copy tr over to seq ops */
1370 m->private = inode->i_private;
1371
1372 return ret;
1373 }
1374
1375 static int ftrace_event_release(struct inode *inode, struct file *file)
1376 {
1377 struct trace_array *tr = inode->i_private;
1378
1379 trace_array_put(tr);
1380
1381 return seq_release(inode, file);
1382 }
1383
1384 static int
1385 ftrace_event_avail_open(struct inode *inode, struct file *file)
1386 {
1387 const struct seq_operations *seq_ops = &show_event_seq_ops;
1388
1389 return ftrace_event_open(inode, file, seq_ops);
1390 }
1391
1392 static int
1393 ftrace_event_set_open(struct inode *inode, struct file *file)
1394 {
1395 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1396 struct trace_array *tr = inode->i_private;
1397 int ret;
1398
1399 if (trace_array_get(tr) < 0)
1400 return -ENODEV;
1401
1402 if ((file->f_mode & FMODE_WRITE) &&
1403 (file->f_flags & O_TRUNC))
1404 ftrace_clear_events(tr);
1405
1406 ret = ftrace_event_open(inode, file, seq_ops);
1407 if (ret < 0)
1408 trace_array_put(tr);
1409 return ret;
1410 }
1411
1412 static struct event_subsystem *
1413 create_new_subsystem(const char *name)
1414 {
1415 struct event_subsystem *system;
1416
1417 /* need to create new entry */
1418 system = kmalloc(sizeof(*system), GFP_KERNEL);
1419 if (!system)
1420 return NULL;
1421
1422 system->ref_count = 1;
1423
1424 /* Only allocate if dynamic (kprobes and modules) */
1425 if (!core_kernel_data((unsigned long)name)) {
1426 system->ref_count |= SYSTEM_FL_FREE_NAME;
1427 system->name = kstrdup(name, GFP_KERNEL);
1428 if (!system->name)
1429 goto out_free;
1430 } else
1431 system->name = name;
1432
1433 system->filter = NULL;
1434
1435 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1436 if (!system->filter)
1437 goto out_free;
1438
1439 list_add(&system->list, &event_subsystems);
1440
1441 return system;
1442
1443 out_free:
1444 if (system->ref_count & SYSTEM_FL_FREE_NAME)
1445 kfree(system->name);
1446 kfree(system);
1447 return NULL;
1448 }
1449
1450 static struct dentry *
1451 event_subsystem_dir(struct trace_array *tr, const char *name,
1452 struct ftrace_event_file *file, struct dentry *parent)
1453 {
1454 struct ftrace_subsystem_dir *dir;
1455 struct event_subsystem *system;
1456 struct dentry *entry;
1457
1458 /* First see if we did not already create this dir */
1459 list_for_each_entry(dir, &tr->systems, list) {
1460 system = dir->subsystem;
1461 if (strcmp(system->name, name) == 0) {
1462 dir->nr_events++;
1463 file->system = dir;
1464 return dir->entry;
1465 }
1466 }
1467
1468 /* Now see if the system itself exists. */
1469 list_for_each_entry(system, &event_subsystems, list) {
1470 if (strcmp(system->name, name) == 0)
1471 break;
1472 }
1473 /* Reset system variable when not found */
1474 if (&system->list == &event_subsystems)
1475 system = NULL;
1476
1477 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1478 if (!dir)
1479 goto out_fail;
1480
1481 if (!system) {
1482 system = create_new_subsystem(name);
1483 if (!system)
1484 goto out_free;
1485 } else
1486 __get_system(system);
1487
1488 dir->entry = debugfs_create_dir(name, parent);
1489 if (!dir->entry) {
1490 pr_warning("Failed to create system directory %s\n", name);
1491 __put_system(system);
1492 goto out_free;
1493 }
1494
1495 dir->tr = tr;
1496 dir->ref_count = 1;
1497 dir->nr_events = 1;
1498 dir->subsystem = system;
1499 file->system = dir;
1500
1501 entry = debugfs_create_file("filter", 0644, dir->entry, dir,
1502 &ftrace_subsystem_filter_fops);
1503 if (!entry) {
1504 kfree(system->filter);
1505 system->filter = NULL;
1506 pr_warning("Could not create debugfs '%s/filter' entry\n", name);
1507 }
1508
1509 trace_create_file("enable", 0644, dir->entry, dir,
1510 &ftrace_system_enable_fops);
1511
1512 list_add(&dir->list, &tr->systems);
1513
1514 return dir->entry;
1515
1516 out_free:
1517 kfree(dir);
1518 out_fail:
1519 /* Only print this message if failed on memory allocation */
1520 if (!dir || !system)
1521 pr_warning("No memory to create event subsystem %s\n",
1522 name);
1523 return NULL;
1524 }
1525
1526 static int
1527 event_create_dir(struct dentry *parent, struct ftrace_event_file *file)
1528 {
1529 struct ftrace_event_call *call = file->event_call;
1530 struct trace_array *tr = file->tr;
1531 struct list_head *head;
1532 struct dentry *d_events;
1533 const char *name;
1534 int ret;
1535
1536 /*
1537 * If the trace point header did not define TRACE_SYSTEM
1538 * then the system would be called "TRACE_SYSTEM".
1539 */
1540 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1541 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1542 if (!d_events)
1543 return -ENOMEM;
1544 } else
1545 d_events = parent;
1546
1547 name = ftrace_event_name(call);
1548 file->dir = debugfs_create_dir(name, d_events);
1549 if (!file->dir) {
1550 pr_warning("Could not create debugfs '%s' directory\n",
1551 name);
1552 return -1;
1553 }
1554
1555 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1556 trace_create_file("enable", 0644, file->dir, file,
1557 &ftrace_enable_fops);
1558
1559 #ifdef CONFIG_PERF_EVENTS
1560 if (call->event.type && call->class->reg)
1561 trace_create_file("id", 0444, file->dir,
1562 (void *)(long)call->event.type,
1563 &ftrace_event_id_fops);
1564 #endif
1565
1566 /*
1567 * Other events may have the same class. Only update
1568 * the fields if they are not already defined.
1569 */
1570 head = trace_get_fields(call);
1571 if (list_empty(head)) {
1572 ret = call->class->define_fields(call);
1573 if (ret < 0) {
1574 pr_warning("Could not initialize trace point"
1575 " events/%s\n", name);
1576 return -1;
1577 }
1578 }
1579 trace_create_file("filter", 0644, file->dir, file,
1580 &ftrace_event_filter_fops);
1581
1582 trace_create_file("trigger", 0644, file->dir, file,
1583 &event_trigger_fops);
1584
1585 trace_create_file("format", 0444, file->dir, call,
1586 &ftrace_event_format_fops);
1587
1588 return 0;
1589 }
1590
1591 static void remove_event_from_tracers(struct ftrace_event_call *call)
1592 {
1593 struct ftrace_event_file *file;
1594 struct trace_array *tr;
1595
1596 do_for_each_event_file_safe(tr, file) {
1597 if (file->event_call != call)
1598 continue;
1599
1600 remove_event_file_dir(file);
1601 /*
1602 * The do_for_each_event_file_safe() is
1603 * a double loop. After finding the call for this
1604 * trace_array, we use break to jump to the next
1605 * trace_array.
1606 */
1607 break;
1608 } while_for_each_event_file();
1609 }
1610
1611 static void event_remove(struct ftrace_event_call *call)
1612 {
1613 struct trace_array *tr;
1614 struct ftrace_event_file *file;
1615
1616 do_for_each_event_file(tr, file) {
1617 if (file->event_call != call)
1618 continue;
1619 ftrace_event_enable_disable(file, 0);
1620 destroy_preds(file);
1621 /*
1622 * The do_for_each_event_file() is
1623 * a double loop. After finding the call for this
1624 * trace_array, we use break to jump to the next
1625 * trace_array.
1626 */
1627 break;
1628 } while_for_each_event_file();
1629
1630 if (call->event.funcs)
1631 __unregister_ftrace_event(&call->event);
1632 remove_event_from_tracers(call);
1633 list_del(&call->list);
1634 }
1635
1636 static int event_init(struct ftrace_event_call *call)
1637 {
1638 int ret = 0;
1639 const char *name;
1640
1641 name = ftrace_event_name(call);
1642 if (WARN_ON(!name))
1643 return -EINVAL;
1644
1645 if (call->class->raw_init) {
1646 ret = call->class->raw_init(call);
1647 if (ret < 0 && ret != -ENOSYS)
1648 pr_warn("Could not initialize trace events/%s\n",
1649 name);
1650 }
1651
1652 return ret;
1653 }
1654
1655 static int
1656 __register_event(struct ftrace_event_call *call, struct module *mod)
1657 {
1658 int ret;
1659
1660 ret = event_init(call);
1661 if (ret < 0)
1662 return ret;
1663
1664 list_add(&call->list, &ftrace_events);
1665 call->mod = mod;
1666
1667 return 0;
1668 }
1669
1670 static struct ftrace_event_file *
1671 trace_create_new_event(struct ftrace_event_call *call,
1672 struct trace_array *tr)
1673 {
1674 struct ftrace_event_file *file;
1675
1676 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
1677 if (!file)
1678 return NULL;
1679
1680 file->event_call = call;
1681 file->tr = tr;
1682 atomic_set(&file->sm_ref, 0);
1683 atomic_set(&file->tm_ref, 0);
1684 INIT_LIST_HEAD(&file->triggers);
1685 list_add(&file->list, &tr->events);
1686
1687 return file;
1688 }
1689
1690 /* Add an event to a trace directory */
1691 static int
1692 __trace_add_new_event(struct ftrace_event_call *call, struct trace_array *tr)
1693 {
1694 struct ftrace_event_file *file;
1695
1696 file = trace_create_new_event(call, tr);
1697 if (!file)
1698 return -ENOMEM;
1699
1700 return event_create_dir(tr->event_dir, file);
1701 }
1702
1703 /*
1704 * Just create a decriptor for early init. A descriptor is required
1705 * for enabling events at boot. We want to enable events before
1706 * the filesystem is initialized.
1707 */
1708 static __init int
1709 __trace_early_add_new_event(struct ftrace_event_call *call,
1710 struct trace_array *tr)
1711 {
1712 struct ftrace_event_file *file;
1713
1714 file = trace_create_new_event(call, tr);
1715 if (!file)
1716 return -ENOMEM;
1717
1718 return 0;
1719 }
1720
1721 struct ftrace_module_file_ops;
1722 static void __add_event_to_tracers(struct ftrace_event_call *call);
1723
1724 /* Add an additional event_call dynamically */
1725 int trace_add_event_call(struct ftrace_event_call *call)
1726 {
1727 int ret;
1728 mutex_lock(&trace_types_lock);
1729 mutex_lock(&event_mutex);
1730
1731 ret = __register_event(call, NULL);
1732 if (ret >= 0)
1733 __add_event_to_tracers(call);
1734
1735 mutex_unlock(&event_mutex);
1736 mutex_unlock(&trace_types_lock);
1737 return ret;
1738 }
1739
1740 /*
1741 * Must be called under locking of trace_types_lock, event_mutex and
1742 * trace_event_sem.
1743 */
1744 static void __trace_remove_event_call(struct ftrace_event_call *call)
1745 {
1746 event_remove(call);
1747 trace_destroy_fields(call);
1748 destroy_call_preds(call);
1749 }
1750
1751 static int probe_remove_event_call(struct ftrace_event_call *call)
1752 {
1753 struct trace_array *tr;
1754 struct ftrace_event_file *file;
1755
1756 #ifdef CONFIG_PERF_EVENTS
1757 if (call->perf_refcount)
1758 return -EBUSY;
1759 #endif
1760 do_for_each_event_file(tr, file) {
1761 if (file->event_call != call)
1762 continue;
1763 /*
1764 * We can't rely on ftrace_event_enable_disable(enable => 0)
1765 * we are going to do, FTRACE_EVENT_FL_SOFT_MODE can suppress
1766 * TRACE_REG_UNREGISTER.
1767 */
1768 if (file->flags & FTRACE_EVENT_FL_ENABLED)
1769 return -EBUSY;
1770 /*
1771 * The do_for_each_event_file_safe() is
1772 * a double loop. After finding the call for this
1773 * trace_array, we use break to jump to the next
1774 * trace_array.
1775 */
1776 break;
1777 } while_for_each_event_file();
1778
1779 __trace_remove_event_call(call);
1780
1781 return 0;
1782 }
1783
1784 /* Remove an event_call */
1785 int trace_remove_event_call(struct ftrace_event_call *call)
1786 {
1787 int ret;
1788
1789 mutex_lock(&trace_types_lock);
1790 mutex_lock(&event_mutex);
1791 down_write(&trace_event_sem);
1792 ret = probe_remove_event_call(call);
1793 up_write(&trace_event_sem);
1794 mutex_unlock(&event_mutex);
1795 mutex_unlock(&trace_types_lock);
1796
1797 return ret;
1798 }
1799
1800 #define for_each_event(event, start, end) \
1801 for (event = start; \
1802 (unsigned long)event < (unsigned long)end; \
1803 event++)
1804
1805 #ifdef CONFIG_MODULES
1806
1807 static void trace_module_add_events(struct module *mod)
1808 {
1809 struct ftrace_event_call **call, **start, **end;
1810
1811 if (!mod->num_trace_events)
1812 return;
1813
1814 /* Don't add infrastructure for mods without tracepoints */
1815 if (trace_module_has_bad_taint(mod)) {
1816 pr_err("%s: module has bad taint, not creating trace events\n",
1817 mod->name);
1818 return;
1819 }
1820
1821 start = mod->trace_events;
1822 end = mod->trace_events + mod->num_trace_events;
1823
1824 for_each_event(call, start, end) {
1825 __register_event(*call, mod);
1826 __add_event_to_tracers(*call);
1827 }
1828 }
1829
1830 static void trace_module_remove_events(struct module *mod)
1831 {
1832 struct ftrace_event_call *call, *p;
1833 bool clear_trace = false;
1834
1835 down_write(&trace_event_sem);
1836 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1837 if (call->mod == mod) {
1838 if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
1839 clear_trace = true;
1840 __trace_remove_event_call(call);
1841 }
1842 }
1843 up_write(&trace_event_sem);
1844
1845 /*
1846 * It is safest to reset the ring buffer if the module being unloaded
1847 * registered any events that were used. The only worry is if
1848 * a new module gets loaded, and takes on the same id as the events
1849 * of this module. When printing out the buffer, traced events left
1850 * over from this module may be passed to the new module events and
1851 * unexpected results may occur.
1852 */
1853 if (clear_trace)
1854 tracing_reset_all_online_cpus();
1855 }
1856
1857 static int trace_module_notify(struct notifier_block *self,
1858 unsigned long val, void *data)
1859 {
1860 struct module *mod = data;
1861
1862 mutex_lock(&trace_types_lock);
1863 mutex_lock(&event_mutex);
1864 switch (val) {
1865 case MODULE_STATE_COMING:
1866 trace_module_add_events(mod);
1867 break;
1868 case MODULE_STATE_GOING:
1869 trace_module_remove_events(mod);
1870 break;
1871 }
1872 mutex_unlock(&event_mutex);
1873 mutex_unlock(&trace_types_lock);
1874
1875 return 0;
1876 }
1877
1878 static struct notifier_block trace_module_nb = {
1879 .notifier_call = trace_module_notify,
1880 .priority = 0,
1881 };
1882 #endif /* CONFIG_MODULES */
1883
1884 /* Create a new event directory structure for a trace directory. */
1885 static void
1886 __trace_add_event_dirs(struct trace_array *tr)
1887 {
1888 struct ftrace_event_call *call;
1889 int ret;
1890
1891 list_for_each_entry(call, &ftrace_events, list) {
1892 ret = __trace_add_new_event(call, tr);
1893 if (ret < 0)
1894 pr_warning("Could not create directory for event %s\n",
1895 ftrace_event_name(call));
1896 }
1897 }
1898
1899 struct ftrace_event_file *
1900 find_event_file(struct trace_array *tr, const char *system, const char *event)
1901 {
1902 struct ftrace_event_file *file;
1903 struct ftrace_event_call *call;
1904 const char *name;
1905
1906 list_for_each_entry(file, &tr->events, list) {
1907
1908 call = file->event_call;
1909 name = ftrace_event_name(call);
1910
1911 if (!name || !call->class || !call->class->reg)
1912 continue;
1913
1914 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1915 continue;
1916
1917 if (strcmp(event, name) == 0 &&
1918 strcmp(system, call->class->system) == 0)
1919 return file;
1920 }
1921 return NULL;
1922 }
1923
1924 #ifdef CONFIG_DYNAMIC_FTRACE
1925
1926 /* Avoid typos */
1927 #define ENABLE_EVENT_STR "enable_event"
1928 #define DISABLE_EVENT_STR "disable_event"
1929
1930 struct event_probe_data {
1931 struct ftrace_event_file *file;
1932 unsigned long count;
1933 int ref;
1934 bool enable;
1935 };
1936
1937 static void
1938 event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1939 {
1940 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1941 struct event_probe_data *data = *pdata;
1942
1943 if (!data)
1944 return;
1945
1946 if (data->enable)
1947 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1948 else
1949 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1950 }
1951
1952 static void
1953 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1954 {
1955 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1956 struct event_probe_data *data = *pdata;
1957
1958 if (!data)
1959 return;
1960
1961 if (!data->count)
1962 return;
1963
1964 /* Skip if the event is in a state we want to switch to */
1965 if (data->enable == !(data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
1966 return;
1967
1968 if (data->count != -1)
1969 (data->count)--;
1970
1971 event_enable_probe(ip, parent_ip, _data);
1972 }
1973
1974 static int
1975 event_enable_print(struct seq_file *m, unsigned long ip,
1976 struct ftrace_probe_ops *ops, void *_data)
1977 {
1978 struct event_probe_data *data = _data;
1979
1980 seq_printf(m, "%ps:", (void *)ip);
1981
1982 seq_printf(m, "%s:%s:%s",
1983 data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
1984 data->file->event_call->class->system,
1985 ftrace_event_name(data->file->event_call));
1986
1987 if (data->count == -1)
1988 seq_printf(m, ":unlimited\n");
1989 else
1990 seq_printf(m, ":count=%ld\n", data->count);
1991
1992 return 0;
1993 }
1994
1995 static int
1996 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
1997 void **_data)
1998 {
1999 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2000 struct event_probe_data *data = *pdata;
2001
2002 data->ref++;
2003 return 0;
2004 }
2005
2006 static void
2007 event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
2008 void **_data)
2009 {
2010 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2011 struct event_probe_data *data = *pdata;
2012
2013 if (WARN_ON_ONCE(data->ref <= 0))
2014 return;
2015
2016 data->ref--;
2017 if (!data->ref) {
2018 /* Remove the SOFT_MODE flag */
2019 __ftrace_event_enable_disable(data->file, 0, 1);
2020 module_put(data->file->event_call->mod);
2021 kfree(data);
2022 }
2023 *pdata = NULL;
2024 }
2025
2026 static struct ftrace_probe_ops event_enable_probe_ops = {
2027 .func = event_enable_probe,
2028 .print = event_enable_print,
2029 .init = event_enable_init,
2030 .free = event_enable_free,
2031 };
2032
2033 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2034 .func = event_enable_count_probe,
2035 .print = event_enable_print,
2036 .init = event_enable_init,
2037 .free = event_enable_free,
2038 };
2039
2040 static struct ftrace_probe_ops event_disable_probe_ops = {
2041 .func = event_enable_probe,
2042 .print = event_enable_print,
2043 .init = event_enable_init,
2044 .free = event_enable_free,
2045 };
2046
2047 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2048 .func = event_enable_count_probe,
2049 .print = event_enable_print,
2050 .init = event_enable_init,
2051 .free = event_enable_free,
2052 };
2053
2054 static int
2055 event_enable_func(struct ftrace_hash *hash,
2056 char *glob, char *cmd, char *param, int enabled)
2057 {
2058 struct trace_array *tr = top_trace_array();
2059 struct ftrace_event_file *file;
2060 struct ftrace_probe_ops *ops;
2061 struct event_probe_data *data;
2062 const char *system;
2063 const char *event;
2064 char *number;
2065 bool enable;
2066 int ret;
2067
2068 /* hash funcs only work with set_ftrace_filter */
2069 if (!enabled || !param)
2070 return -EINVAL;
2071
2072 system = strsep(&param, ":");
2073 if (!param)
2074 return -EINVAL;
2075
2076 event = strsep(&param, ":");
2077
2078 mutex_lock(&event_mutex);
2079
2080 ret = -EINVAL;
2081 file = find_event_file(tr, system, event);
2082 if (!file)
2083 goto out;
2084
2085 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2086
2087 if (enable)
2088 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2089 else
2090 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2091
2092 if (glob[0] == '!') {
2093 unregister_ftrace_function_probe_func(glob+1, ops);
2094 ret = 0;
2095 goto out;
2096 }
2097
2098 ret = -ENOMEM;
2099 data = kzalloc(sizeof(*data), GFP_KERNEL);
2100 if (!data)
2101 goto out;
2102
2103 data->enable = enable;
2104 data->count = -1;
2105 data->file = file;
2106
2107 if (!param)
2108 goto out_reg;
2109
2110 number = strsep(&param, ":");
2111
2112 ret = -EINVAL;
2113 if (!strlen(number))
2114 goto out_free;
2115
2116 /*
2117 * We use the callback data field (which is a pointer)
2118 * as our counter.
2119 */
2120 ret = kstrtoul(number, 0, &data->count);
2121 if (ret)
2122 goto out_free;
2123
2124 out_reg:
2125 /* Don't let event modules unload while probe registered */
2126 ret = try_module_get(file->event_call->mod);
2127 if (!ret) {
2128 ret = -EBUSY;
2129 goto out_free;
2130 }
2131
2132 ret = __ftrace_event_enable_disable(file, 1, 1);
2133 if (ret < 0)
2134 goto out_put;
2135 ret = register_ftrace_function_probe(glob, ops, data);
2136 /*
2137 * The above returns on success the # of functions enabled,
2138 * but if it didn't find any functions it returns zero.
2139 * Consider no functions a failure too.
2140 */
2141 if (!ret) {
2142 ret = -ENOENT;
2143 goto out_disable;
2144 } else if (ret < 0)
2145 goto out_disable;
2146 /* Just return zero, not the number of enabled functions */
2147 ret = 0;
2148 out:
2149 mutex_unlock(&event_mutex);
2150 return ret;
2151
2152 out_disable:
2153 __ftrace_event_enable_disable(file, 0, 1);
2154 out_put:
2155 module_put(file->event_call->mod);
2156 out_free:
2157 kfree(data);
2158 goto out;
2159 }
2160
2161 static struct ftrace_func_command event_enable_cmd = {
2162 .name = ENABLE_EVENT_STR,
2163 .func = event_enable_func,
2164 };
2165
2166 static struct ftrace_func_command event_disable_cmd = {
2167 .name = DISABLE_EVENT_STR,
2168 .func = event_enable_func,
2169 };
2170
2171 static __init int register_event_cmds(void)
2172 {
2173 int ret;
2174
2175 ret = register_ftrace_command(&event_enable_cmd);
2176 if (WARN_ON(ret < 0))
2177 return ret;
2178 ret = register_ftrace_command(&event_disable_cmd);
2179 if (WARN_ON(ret < 0))
2180 unregister_ftrace_command(&event_enable_cmd);
2181 return ret;
2182 }
2183 #else
2184 static inline int register_event_cmds(void) { return 0; }
2185 #endif /* CONFIG_DYNAMIC_FTRACE */
2186
2187 /*
2188 * The top level array has already had its ftrace_event_file
2189 * descriptors created in order to allow for early events to
2190 * be recorded. This function is called after the debugfs has been
2191 * initialized, and we now have to create the files associated
2192 * to the events.
2193 */
2194 static __init void
2195 __trace_early_add_event_dirs(struct trace_array *tr)
2196 {
2197 struct ftrace_event_file *file;
2198 int ret;
2199
2200
2201 list_for_each_entry(file, &tr->events, list) {
2202 ret = event_create_dir(tr->event_dir, file);
2203 if (ret < 0)
2204 pr_warning("Could not create directory for event %s\n",
2205 ftrace_event_name(file->event_call));
2206 }
2207 }
2208
2209 /*
2210 * For early boot up, the top trace array requires to have
2211 * a list of events that can be enabled. This must be done before
2212 * the filesystem is set up in order to allow events to be traced
2213 * early.
2214 */
2215 static __init void
2216 __trace_early_add_events(struct trace_array *tr)
2217 {
2218 struct ftrace_event_call *call;
2219 int ret;
2220
2221 list_for_each_entry(call, &ftrace_events, list) {
2222 /* Early boot up should not have any modules loaded */
2223 if (WARN_ON_ONCE(call->mod))
2224 continue;
2225
2226 ret = __trace_early_add_new_event(call, tr);
2227 if (ret < 0)
2228 pr_warning("Could not create early event %s\n",
2229 ftrace_event_name(call));
2230 }
2231 }
2232
2233 /* Remove the event directory structure for a trace directory. */
2234 static void
2235 __trace_remove_event_dirs(struct trace_array *tr)
2236 {
2237 struct ftrace_event_file *file, *next;
2238
2239 list_for_each_entry_safe(file, next, &tr->events, list)
2240 remove_event_file_dir(file);
2241 }
2242
2243 static void __add_event_to_tracers(struct ftrace_event_call *call)
2244 {
2245 struct trace_array *tr;
2246
2247 list_for_each_entry(tr, &ftrace_trace_arrays, list)
2248 __trace_add_new_event(call, tr);
2249 }
2250
2251 extern struct ftrace_event_call *__start_ftrace_events[];
2252 extern struct ftrace_event_call *__stop_ftrace_events[];
2253
2254 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2255
2256 static __init int setup_trace_event(char *str)
2257 {
2258 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2259 ring_buffer_expanded = true;
2260 tracing_selftest_disabled = true;
2261
2262 return 1;
2263 }
2264 __setup("trace_event=", setup_trace_event);
2265
2266 /* Expects to have event_mutex held when called */
2267 static int
2268 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2269 {
2270 struct dentry *d_events;
2271 struct dentry *entry;
2272
2273 entry = debugfs_create_file("set_event", 0644, parent,
2274 tr, &ftrace_set_event_fops);
2275 if (!entry) {
2276 pr_warning("Could not create debugfs 'set_event' entry\n");
2277 return -ENOMEM;
2278 }
2279
2280 d_events = debugfs_create_dir("events", parent);
2281 if (!d_events) {
2282 pr_warning("Could not create debugfs 'events' directory\n");
2283 return -ENOMEM;
2284 }
2285
2286 /* ring buffer internal formats */
2287 trace_create_file("header_page", 0444, d_events,
2288 ring_buffer_print_page_header,
2289 &ftrace_show_header_fops);
2290
2291 trace_create_file("header_event", 0444, d_events,
2292 ring_buffer_print_entry_header,
2293 &ftrace_show_header_fops);
2294
2295 trace_create_file("enable", 0644, d_events,
2296 tr, &ftrace_tr_enable_fops);
2297
2298 tr->event_dir = d_events;
2299
2300 return 0;
2301 }
2302
2303 /**
2304 * event_trace_add_tracer - add a instance of a trace_array to events
2305 * @parent: The parent dentry to place the files/directories for events in
2306 * @tr: The trace array associated with these events
2307 *
2308 * When a new instance is created, it needs to set up its events
2309 * directory, as well as other files associated with events. It also
2310 * creates the event hierachry in the @parent/events directory.
2311 *
2312 * Returns 0 on success.
2313 */
2314 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2315 {
2316 int ret;
2317
2318 mutex_lock(&event_mutex);
2319
2320 ret = create_event_toplevel_files(parent, tr);
2321 if (ret)
2322 goto out_unlock;
2323
2324 down_write(&trace_event_sem);
2325 __trace_add_event_dirs(tr);
2326 up_write(&trace_event_sem);
2327
2328 out_unlock:
2329 mutex_unlock(&event_mutex);
2330
2331 return ret;
2332 }
2333
2334 /*
2335 * The top trace array already had its file descriptors created.
2336 * Now the files themselves need to be created.
2337 */
2338 static __init int
2339 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2340 {
2341 int ret;
2342
2343 mutex_lock(&event_mutex);
2344
2345 ret = create_event_toplevel_files(parent, tr);
2346 if (ret)
2347 goto out_unlock;
2348
2349 down_write(&trace_event_sem);
2350 __trace_early_add_event_dirs(tr);
2351 up_write(&trace_event_sem);
2352
2353 out_unlock:
2354 mutex_unlock(&event_mutex);
2355
2356 return ret;
2357 }
2358
2359 int event_trace_del_tracer(struct trace_array *tr)
2360 {
2361 mutex_lock(&event_mutex);
2362
2363 /* Disable any event triggers and associated soft-disabled events */
2364 clear_event_triggers(tr);
2365
2366 /* Disable any running events */
2367 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
2368
2369 /* Access to events are within rcu_read_lock_sched() */
2370 synchronize_sched();
2371
2372 down_write(&trace_event_sem);
2373 __trace_remove_event_dirs(tr);
2374 debugfs_remove_recursive(tr->event_dir);
2375 up_write(&trace_event_sem);
2376
2377 tr->event_dir = NULL;
2378
2379 mutex_unlock(&event_mutex);
2380
2381 return 0;
2382 }
2383
2384 static __init int event_trace_memsetup(void)
2385 {
2386 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
2387 file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC);
2388 return 0;
2389 }
2390
2391 static __init int event_trace_enable(void)
2392 {
2393 struct trace_array *tr = top_trace_array();
2394 struct ftrace_event_call **iter, *call;
2395 char *buf = bootup_event_buf;
2396 char *token;
2397 int ret;
2398
2399 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
2400
2401 call = *iter;
2402 ret = event_init(call);
2403 if (!ret)
2404 list_add(&call->list, &ftrace_events);
2405 }
2406
2407 /*
2408 * We need the top trace array to have a working set of trace
2409 * points at early init, before the debug files and directories
2410 * are created. Create the file entries now, and attach them
2411 * to the actual file dentries later.
2412 */
2413 __trace_early_add_events(tr);
2414
2415 while (true) {
2416 token = strsep(&buf, ",");
2417
2418 if (!token)
2419 break;
2420 if (!*token)
2421 continue;
2422
2423 ret = ftrace_set_clr_event(tr, token, 1);
2424 if (ret)
2425 pr_warn("Failed to enable trace event: %s\n", token);
2426 }
2427
2428 trace_printk_start_comm();
2429
2430 register_event_cmds();
2431
2432 register_trigger_cmds();
2433
2434 return 0;
2435 }
2436
2437 static __init int event_trace_init(void)
2438 {
2439 struct trace_array *tr;
2440 struct dentry *d_tracer;
2441 struct dentry *entry;
2442 int ret;
2443
2444 tr = top_trace_array();
2445
2446 d_tracer = tracing_init_dentry();
2447 if (!d_tracer)
2448 return 0;
2449
2450 entry = debugfs_create_file("available_events", 0444, d_tracer,
2451 tr, &ftrace_avail_fops);
2452 if (!entry)
2453 pr_warning("Could not create debugfs "
2454 "'available_events' entry\n");
2455
2456 if (trace_define_common_fields())
2457 pr_warning("tracing: Failed to allocate common fields");
2458
2459 ret = early_event_add_tracer(d_tracer, tr);
2460 if (ret)
2461 return ret;
2462
2463 #ifdef CONFIG_MODULES
2464 ret = register_module_notifier(&trace_module_nb);
2465 if (ret)
2466 pr_warning("Failed to register trace events module notifier\n");
2467 #endif
2468 return 0;
2469 }
2470 early_initcall(event_trace_memsetup);
2471 core_initcall(event_trace_enable);
2472 fs_initcall(event_trace_init);
2473
2474 #ifdef CONFIG_FTRACE_STARTUP_TEST
2475
2476 static DEFINE_SPINLOCK(test_spinlock);
2477 static DEFINE_SPINLOCK(test_spinlock_irq);
2478 static DEFINE_MUTEX(test_mutex);
2479
2480 static __init void test_work(struct work_struct *dummy)
2481 {
2482 spin_lock(&test_spinlock);
2483 spin_lock_irq(&test_spinlock_irq);
2484 udelay(1);
2485 spin_unlock_irq(&test_spinlock_irq);
2486 spin_unlock(&test_spinlock);
2487
2488 mutex_lock(&test_mutex);
2489 msleep(1);
2490 mutex_unlock(&test_mutex);
2491 }
2492
2493 static __init int event_test_thread(void *unused)
2494 {
2495 void *test_malloc;
2496
2497 test_malloc = kmalloc(1234, GFP_KERNEL);
2498 if (!test_malloc)
2499 pr_info("failed to kmalloc\n");
2500
2501 schedule_on_each_cpu(test_work);
2502
2503 kfree(test_malloc);
2504
2505 set_current_state(TASK_INTERRUPTIBLE);
2506 while (!kthread_should_stop())
2507 schedule();
2508
2509 return 0;
2510 }
2511
2512 /*
2513 * Do various things that may trigger events.
2514 */
2515 static __init void event_test_stuff(void)
2516 {
2517 struct task_struct *test_thread;
2518
2519 test_thread = kthread_run(event_test_thread, NULL, "test-events");
2520 msleep(1);
2521 kthread_stop(test_thread);
2522 }
2523
2524 /*
2525 * For every trace event defined, we will test each trace point separately,
2526 * and then by groups, and finally all trace points.
2527 */
2528 static __init void event_trace_self_tests(void)
2529 {
2530 struct ftrace_subsystem_dir *dir;
2531 struct ftrace_event_file *file;
2532 struct ftrace_event_call *call;
2533 struct event_subsystem *system;
2534 struct trace_array *tr;
2535 int ret;
2536
2537 tr = top_trace_array();
2538
2539 pr_info("Running tests on trace events:\n");
2540
2541 list_for_each_entry(file, &tr->events, list) {
2542
2543 call = file->event_call;
2544
2545 /* Only test those that have a probe */
2546 if (!call->class || !call->class->probe)
2547 continue;
2548
2549 /*
2550 * Testing syscall events here is pretty useless, but
2551 * we still do it if configured. But this is time consuming.
2552 * What we really need is a user thread to perform the
2553 * syscalls as we test.
2554 */
2555 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
2556 if (call->class->system &&
2557 strcmp(call->class->system, "syscalls") == 0)
2558 continue;
2559 #endif
2560
2561 pr_info("Testing event %s: ", ftrace_event_name(call));
2562
2563 /*
2564 * If an event is already enabled, someone is using
2565 * it and the self test should not be on.
2566 */
2567 if (file->flags & FTRACE_EVENT_FL_ENABLED) {
2568 pr_warning("Enabled event during self test!\n");
2569 WARN_ON_ONCE(1);
2570 continue;
2571 }
2572
2573 ftrace_event_enable_disable(file, 1);
2574 event_test_stuff();
2575 ftrace_event_enable_disable(file, 0);
2576
2577 pr_cont("OK\n");
2578 }
2579
2580 /* Now test at the sub system level */
2581
2582 pr_info("Running tests on trace event systems:\n");
2583
2584 list_for_each_entry(dir, &tr->systems, list) {
2585
2586 system = dir->subsystem;
2587
2588 /* the ftrace system is special, skip it */
2589 if (strcmp(system->name, "ftrace") == 0)
2590 continue;
2591
2592 pr_info("Testing event system %s: ", system->name);
2593
2594 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
2595 if (WARN_ON_ONCE(ret)) {
2596 pr_warning("error enabling system %s\n",
2597 system->name);
2598 continue;
2599 }
2600
2601 event_test_stuff();
2602
2603 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
2604 if (WARN_ON_ONCE(ret)) {
2605 pr_warning("error disabling system %s\n",
2606 system->name);
2607 continue;
2608 }
2609
2610 pr_cont("OK\n");
2611 }
2612
2613 /* Test with all events enabled */
2614
2615 pr_info("Running tests on all trace events:\n");
2616 pr_info("Testing all events: ");
2617
2618 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
2619 if (WARN_ON_ONCE(ret)) {
2620 pr_warning("error enabling all events\n");
2621 return;
2622 }
2623
2624 event_test_stuff();
2625
2626 /* reset sysname */
2627 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
2628 if (WARN_ON_ONCE(ret)) {
2629 pr_warning("error disabling all events\n");
2630 return;
2631 }
2632
2633 pr_cont("OK\n");
2634 }
2635
2636 #ifdef CONFIG_FUNCTION_TRACER
2637
2638 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
2639
2640 static void
2641 function_test_events_call(unsigned long ip, unsigned long parent_ip,
2642 struct ftrace_ops *op, struct pt_regs *pt_regs)
2643 {
2644 struct ring_buffer_event *event;
2645 struct ring_buffer *buffer;
2646 struct ftrace_entry *entry;
2647 unsigned long flags;
2648 long disabled;
2649 int cpu;
2650 int pc;
2651
2652 pc = preempt_count();
2653 preempt_disable_notrace();
2654 cpu = raw_smp_processor_id();
2655 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
2656
2657 if (disabled != 1)
2658 goto out;
2659
2660 local_save_flags(flags);
2661
2662 event = trace_current_buffer_lock_reserve(&buffer,
2663 TRACE_FN, sizeof(*entry),
2664 flags, pc);
2665 if (!event)
2666 goto out;
2667 entry = ring_buffer_event_data(event);
2668 entry->ip = ip;
2669 entry->parent_ip = parent_ip;
2670
2671 trace_buffer_unlock_commit(buffer, event, flags, pc);
2672
2673 out:
2674 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
2675 preempt_enable_notrace();
2676 }
2677
2678 static struct ftrace_ops trace_ops __initdata =
2679 {
2680 .func = function_test_events_call,
2681 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
2682 };
2683
2684 static __init void event_trace_self_test_with_function(void)
2685 {
2686 int ret;
2687 ret = register_ftrace_function(&trace_ops);
2688 if (WARN_ON(ret < 0)) {
2689 pr_info("Failed to enable function tracer for event tests\n");
2690 return;
2691 }
2692 pr_info("Running tests again, along with the function tracer\n");
2693 event_trace_self_tests();
2694 unregister_ftrace_function(&trace_ops);
2695 }
2696 #else
2697 static __init void event_trace_self_test_with_function(void)
2698 {
2699 }
2700 #endif
2701
2702 static __init int event_trace_self_tests_init(void)
2703 {
2704 if (!tracing_selftest_disabled) {
2705 event_trace_self_tests();
2706 event_trace_self_test_with_function();
2707 }
2708
2709 return 0;
2710 }
2711
2712 late_initcall(event_trace_self_tests_init);
2713
2714 #endif
(deprecated) Btrfs devel tree