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Merge tag 'ktest-v3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...
[deliverable/linux.git] / kernel / trace / trace_events.c
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 free_event_filter(file->filter);
474 kmem_cache_free(file_cachep, file);
475 }
476
477 /*
478 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
479 */
480 static int
481 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
482 const char *sub, const char *event, int set)
483 {
484 struct ftrace_event_file *file;
485 struct ftrace_event_call *call;
486 const char *name;
487 int ret = -EINVAL;
488
489 list_for_each_entry(file, &tr->events, list) {
490
491 call = file->event_call;
492 name = ftrace_event_name(call);
493
494 if (!name || !call->class || !call->class->reg)
495 continue;
496
497 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
498 continue;
499
500 if (match &&
501 strcmp(match, name) != 0 &&
502 strcmp(match, call->class->system) != 0)
503 continue;
504
505 if (sub && strcmp(sub, call->class->system) != 0)
506 continue;
507
508 if (event && strcmp(event, name) != 0)
509 continue;
510
511 ftrace_event_enable_disable(file, set);
512
513 ret = 0;
514 }
515
516 return ret;
517 }
518
519 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
520 const char *sub, const char *event, int set)
521 {
522 int ret;
523
524 mutex_lock(&event_mutex);
525 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
526 mutex_unlock(&event_mutex);
527
528 return ret;
529 }
530
531 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
532 {
533 char *event = NULL, *sub = NULL, *match;
534
535 /*
536 * The buf format can be <subsystem>:<event-name>
537 * *:<event-name> means any event by that name.
538 * :<event-name> is the same.
539 *
540 * <subsystem>:* means all events in that subsystem
541 * <subsystem>: means the same.
542 *
543 * <name> (no ':') means all events in a subsystem with
544 * the name <name> or any event that matches <name>
545 */
546
547 match = strsep(&buf, ":");
548 if (buf) {
549 sub = match;
550 event = buf;
551 match = NULL;
552
553 if (!strlen(sub) || strcmp(sub, "*") == 0)
554 sub = NULL;
555 if (!strlen(event) || strcmp(event, "*") == 0)
556 event = NULL;
557 }
558
559 return __ftrace_set_clr_event(tr, match, sub, event, set);
560 }
561
562 /**
563 * trace_set_clr_event - enable or disable an event
564 * @system: system name to match (NULL for any system)
565 * @event: event name to match (NULL for all events, within system)
566 * @set: 1 to enable, 0 to disable
567 *
568 * This is a way for other parts of the kernel to enable or disable
569 * event recording.
570 *
571 * Returns 0 on success, -EINVAL if the parameters do not match any
572 * registered events.
573 */
574 int trace_set_clr_event(const char *system, const char *event, int set)
575 {
576 struct trace_array *tr = top_trace_array();
577
578 if (!tr)
579 return -ENODEV;
580
581 return __ftrace_set_clr_event(tr, NULL, system, event, set);
582 }
583 EXPORT_SYMBOL_GPL(trace_set_clr_event);
584
585 /* 128 should be much more than enough */
586 #define EVENT_BUF_SIZE 127
587
588 static ssize_t
589 ftrace_event_write(struct file *file, const char __user *ubuf,
590 size_t cnt, loff_t *ppos)
591 {
592 struct trace_parser parser;
593 struct seq_file *m = file->private_data;
594 struct trace_array *tr = m->private;
595 ssize_t read, ret;
596
597 if (!cnt)
598 return 0;
599
600 ret = tracing_update_buffers();
601 if (ret < 0)
602 return ret;
603
604 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
605 return -ENOMEM;
606
607 read = trace_get_user(&parser, ubuf, cnt, ppos);
608
609 if (read >= 0 && trace_parser_loaded((&parser))) {
610 int set = 1;
611
612 if (*parser.buffer == '!')
613 set = 0;
614
615 parser.buffer[parser.idx] = 0;
616
617 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
618 if (ret)
619 goto out_put;
620 }
621
622 ret = read;
623
624 out_put:
625 trace_parser_put(&parser);
626
627 return ret;
628 }
629
630 static void *
631 t_next(struct seq_file *m, void *v, loff_t *pos)
632 {
633 struct ftrace_event_file *file = v;
634 struct ftrace_event_call *call;
635 struct trace_array *tr = m->private;
636
637 (*pos)++;
638
639 list_for_each_entry_continue(file, &tr->events, list) {
640 call = file->event_call;
641 /*
642 * The ftrace subsystem is for showing formats only.
643 * They can not be enabled or disabled via the event files.
644 */
645 if (call->class && call->class->reg)
646 return file;
647 }
648
649 return NULL;
650 }
651
652 static void *t_start(struct seq_file *m, loff_t *pos)
653 {
654 struct ftrace_event_file *file;
655 struct trace_array *tr = m->private;
656 loff_t l;
657
658 mutex_lock(&event_mutex);
659
660 file = list_entry(&tr->events, struct ftrace_event_file, list);
661 for (l = 0; l <= *pos; ) {
662 file = t_next(m, file, &l);
663 if (!file)
664 break;
665 }
666 return file;
667 }
668
669 static void *
670 s_next(struct seq_file *m, void *v, loff_t *pos)
671 {
672 struct ftrace_event_file *file = v;
673 struct trace_array *tr = m->private;
674
675 (*pos)++;
676
677 list_for_each_entry_continue(file, &tr->events, list) {
678 if (file->flags & FTRACE_EVENT_FL_ENABLED)
679 return file;
680 }
681
682 return NULL;
683 }
684
685 static void *s_start(struct seq_file *m, loff_t *pos)
686 {
687 struct ftrace_event_file *file;
688 struct trace_array *tr = m->private;
689 loff_t l;
690
691 mutex_lock(&event_mutex);
692
693 file = list_entry(&tr->events, struct ftrace_event_file, list);
694 for (l = 0; l <= *pos; ) {
695 file = s_next(m, file, &l);
696 if (!file)
697 break;
698 }
699 return file;
700 }
701
702 static int t_show(struct seq_file *m, void *v)
703 {
704 struct ftrace_event_file *file = v;
705 struct ftrace_event_call *call = file->event_call;
706
707 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
708 seq_printf(m, "%s:", call->class->system);
709 seq_printf(m, "%s\n", ftrace_event_name(call));
710
711 return 0;
712 }
713
714 static void t_stop(struct seq_file *m, void *p)
715 {
716 mutex_unlock(&event_mutex);
717 }
718
719 static ssize_t
720 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
721 loff_t *ppos)
722 {
723 struct ftrace_event_file *file;
724 unsigned long flags;
725 char buf[4] = "0";
726
727 mutex_lock(&event_mutex);
728 file = event_file_data(filp);
729 if (likely(file))
730 flags = file->flags;
731 mutex_unlock(&event_mutex);
732
733 if (!file)
734 return -ENODEV;
735
736 if (flags & FTRACE_EVENT_FL_ENABLED &&
737 !(flags & FTRACE_EVENT_FL_SOFT_DISABLED))
738 strcpy(buf, "1");
739
740 if (flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
741 flags & FTRACE_EVENT_FL_SOFT_MODE)
742 strcat(buf, "*");
743
744 strcat(buf, "\n");
745
746 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
747 }
748
749 static ssize_t
750 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
751 loff_t *ppos)
752 {
753 struct ftrace_event_file *file;
754 unsigned long val;
755 int ret;
756
757 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
758 if (ret)
759 return ret;
760
761 ret = tracing_update_buffers();
762 if (ret < 0)
763 return ret;
764
765 switch (val) {
766 case 0:
767 case 1:
768 ret = -ENODEV;
769 mutex_lock(&event_mutex);
770 file = event_file_data(filp);
771 if (likely(file))
772 ret = ftrace_event_enable_disable(file, val);
773 mutex_unlock(&event_mutex);
774 break;
775
776 default:
777 return -EINVAL;
778 }
779
780 *ppos += cnt;
781
782 return ret ? ret : cnt;
783 }
784
785 static ssize_t
786 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
787 loff_t *ppos)
788 {
789 const char set_to_char[4] = { '?', '0', '1', 'X' };
790 struct ftrace_subsystem_dir *dir = filp->private_data;
791 struct event_subsystem *system = dir->subsystem;
792 struct ftrace_event_call *call;
793 struct ftrace_event_file *file;
794 struct trace_array *tr = dir->tr;
795 char buf[2];
796 int set = 0;
797 int ret;
798
799 mutex_lock(&event_mutex);
800 list_for_each_entry(file, &tr->events, list) {
801 call = file->event_call;
802 if (!ftrace_event_name(call) || !call->class || !call->class->reg)
803 continue;
804
805 if (system && strcmp(call->class->system, system->name) != 0)
806 continue;
807
808 /*
809 * We need to find out if all the events are set
810 * or if all events or cleared, or if we have
811 * a mixture.
812 */
813 set |= (1 << !!(file->flags & FTRACE_EVENT_FL_ENABLED));
814
815 /*
816 * If we have a mixture, no need to look further.
817 */
818 if (set == 3)
819 break;
820 }
821 mutex_unlock(&event_mutex);
822
823 buf[0] = set_to_char[set];
824 buf[1] = '\n';
825
826 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
827
828 return ret;
829 }
830
831 static ssize_t
832 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
833 loff_t *ppos)
834 {
835 struct ftrace_subsystem_dir *dir = filp->private_data;
836 struct event_subsystem *system = dir->subsystem;
837 const char *name = NULL;
838 unsigned long val;
839 ssize_t ret;
840
841 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
842 if (ret)
843 return ret;
844
845 ret = tracing_update_buffers();
846 if (ret < 0)
847 return ret;
848
849 if (val != 0 && val != 1)
850 return -EINVAL;
851
852 /*
853 * Opening of "enable" adds a ref count to system,
854 * so the name is safe to use.
855 */
856 if (system)
857 name = system->name;
858
859 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
860 if (ret)
861 goto out;
862
863 ret = cnt;
864
865 out:
866 *ppos += cnt;
867
868 return ret;
869 }
870
871 enum {
872 FORMAT_HEADER = 1,
873 FORMAT_FIELD_SEPERATOR = 2,
874 FORMAT_PRINTFMT = 3,
875 };
876
877 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
878 {
879 struct ftrace_event_call *call = event_file_data(m->private);
880 struct list_head *common_head = &ftrace_common_fields;
881 struct list_head *head = trace_get_fields(call);
882 struct list_head *node = v;
883
884 (*pos)++;
885
886 switch ((unsigned long)v) {
887 case FORMAT_HEADER:
888 node = common_head;
889 break;
890
891 case FORMAT_FIELD_SEPERATOR:
892 node = head;
893 break;
894
895 case FORMAT_PRINTFMT:
896 /* all done */
897 return NULL;
898 }
899
900 node = node->prev;
901 if (node == common_head)
902 return (void *)FORMAT_FIELD_SEPERATOR;
903 else if (node == head)
904 return (void *)FORMAT_PRINTFMT;
905 else
906 return node;
907 }
908
909 static int f_show(struct seq_file *m, void *v)
910 {
911 struct ftrace_event_call *call = event_file_data(m->private);
912 struct ftrace_event_field *field;
913 const char *array_descriptor;
914
915 switch ((unsigned long)v) {
916 case FORMAT_HEADER:
917 seq_printf(m, "name: %s\n", ftrace_event_name(call));
918 seq_printf(m, "ID: %d\n", call->event.type);
919 seq_printf(m, "format:\n");
920 return 0;
921
922 case FORMAT_FIELD_SEPERATOR:
923 seq_putc(m, '\n');
924 return 0;
925
926 case FORMAT_PRINTFMT:
927 seq_printf(m, "\nprint fmt: %s\n",
928 call->print_fmt);
929 return 0;
930 }
931
932 field = list_entry(v, struct ftrace_event_field, link);
933 /*
934 * Smartly shows the array type(except dynamic array).
935 * Normal:
936 * field:TYPE VAR
937 * If TYPE := TYPE[LEN], it is shown:
938 * field:TYPE VAR[LEN]
939 */
940 array_descriptor = strchr(field->type, '[');
941
942 if (!strncmp(field->type, "__data_loc", 10))
943 array_descriptor = NULL;
944
945 if (!array_descriptor)
946 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
947 field->type, field->name, field->offset,
948 field->size, !!field->is_signed);
949 else
950 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
951 (int)(array_descriptor - field->type),
952 field->type, field->name,
953 array_descriptor, field->offset,
954 field->size, !!field->is_signed);
955
956 return 0;
957 }
958
959 static void *f_start(struct seq_file *m, loff_t *pos)
960 {
961 void *p = (void *)FORMAT_HEADER;
962 loff_t l = 0;
963
964 /* ->stop() is called even if ->start() fails */
965 mutex_lock(&event_mutex);
966 if (!event_file_data(m->private))
967 return ERR_PTR(-ENODEV);
968
969 while (l < *pos && p)
970 p = f_next(m, p, &l);
971
972 return p;
973 }
974
975 static void f_stop(struct seq_file *m, void *p)
976 {
977 mutex_unlock(&event_mutex);
978 }
979
980 static const struct seq_operations trace_format_seq_ops = {
981 .start = f_start,
982 .next = f_next,
983 .stop = f_stop,
984 .show = f_show,
985 };
986
987 static int trace_format_open(struct inode *inode, struct file *file)
988 {
989 struct seq_file *m;
990 int ret;
991
992 ret = seq_open(file, &trace_format_seq_ops);
993 if (ret < 0)
994 return ret;
995
996 m = file->private_data;
997 m->private = file;
998
999 return 0;
1000 }
1001
1002 static ssize_t
1003 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1004 {
1005 int id = (long)event_file_data(filp);
1006 char buf[32];
1007 int len;
1008
1009 if (*ppos)
1010 return 0;
1011
1012 if (unlikely(!id))
1013 return -ENODEV;
1014
1015 len = sprintf(buf, "%d\n", id);
1016
1017 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1018 }
1019
1020 static ssize_t
1021 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1022 loff_t *ppos)
1023 {
1024 struct ftrace_event_file *file;
1025 struct trace_seq *s;
1026 int r = -ENODEV;
1027
1028 if (*ppos)
1029 return 0;
1030
1031 s = kmalloc(sizeof(*s), GFP_KERNEL);
1032
1033 if (!s)
1034 return -ENOMEM;
1035
1036 trace_seq_init(s);
1037
1038 mutex_lock(&event_mutex);
1039 file = event_file_data(filp);
1040 if (file)
1041 print_event_filter(file, s);
1042 mutex_unlock(&event_mutex);
1043
1044 if (file)
1045 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1046
1047 kfree(s);
1048
1049 return r;
1050 }
1051
1052 static ssize_t
1053 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1054 loff_t *ppos)
1055 {
1056 struct ftrace_event_file *file;
1057 char *buf;
1058 int err = -ENODEV;
1059
1060 if (cnt >= PAGE_SIZE)
1061 return -EINVAL;
1062
1063 buf = (char *)__get_free_page(GFP_TEMPORARY);
1064 if (!buf)
1065 return -ENOMEM;
1066
1067 if (copy_from_user(buf, ubuf, cnt)) {
1068 free_page((unsigned long) buf);
1069 return -EFAULT;
1070 }
1071 buf[cnt] = '\0';
1072
1073 mutex_lock(&event_mutex);
1074 file = event_file_data(filp);
1075 if (file)
1076 err = apply_event_filter(file, buf);
1077 mutex_unlock(&event_mutex);
1078
1079 free_page((unsigned long) buf);
1080 if (err < 0)
1081 return err;
1082
1083 *ppos += cnt;
1084
1085 return cnt;
1086 }
1087
1088 static LIST_HEAD(event_subsystems);
1089
1090 static int subsystem_open(struct inode *inode, struct file *filp)
1091 {
1092 struct event_subsystem *system = NULL;
1093 struct ftrace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1094 struct trace_array *tr;
1095 int ret;
1096
1097 if (tracing_is_disabled())
1098 return -ENODEV;
1099
1100 /* Make sure the system still exists */
1101 mutex_lock(&trace_types_lock);
1102 mutex_lock(&event_mutex);
1103 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1104 list_for_each_entry(dir, &tr->systems, list) {
1105 if (dir == inode->i_private) {
1106 /* Don't open systems with no events */
1107 if (dir->nr_events) {
1108 __get_system_dir(dir);
1109 system = dir->subsystem;
1110 }
1111 goto exit_loop;
1112 }
1113 }
1114 }
1115 exit_loop:
1116 mutex_unlock(&event_mutex);
1117 mutex_unlock(&trace_types_lock);
1118
1119 if (!system)
1120 return -ENODEV;
1121
1122 /* Some versions of gcc think dir can be uninitialized here */
1123 WARN_ON(!dir);
1124
1125 /* Still need to increment the ref count of the system */
1126 if (trace_array_get(tr) < 0) {
1127 put_system(dir);
1128 return -ENODEV;
1129 }
1130
1131 ret = tracing_open_generic(inode, filp);
1132 if (ret < 0) {
1133 trace_array_put(tr);
1134 put_system(dir);
1135 }
1136
1137 return ret;
1138 }
1139
1140 static int system_tr_open(struct inode *inode, struct file *filp)
1141 {
1142 struct ftrace_subsystem_dir *dir;
1143 struct trace_array *tr = inode->i_private;
1144 int ret;
1145
1146 if (tracing_is_disabled())
1147 return -ENODEV;
1148
1149 if (trace_array_get(tr) < 0)
1150 return -ENODEV;
1151
1152 /* Make a temporary dir that has no system but points to tr */
1153 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1154 if (!dir) {
1155 trace_array_put(tr);
1156 return -ENOMEM;
1157 }
1158
1159 dir->tr = tr;
1160
1161 ret = tracing_open_generic(inode, filp);
1162 if (ret < 0) {
1163 trace_array_put(tr);
1164 kfree(dir);
1165 return ret;
1166 }
1167
1168 filp->private_data = dir;
1169
1170 return 0;
1171 }
1172
1173 static int subsystem_release(struct inode *inode, struct file *file)
1174 {
1175 struct ftrace_subsystem_dir *dir = file->private_data;
1176
1177 trace_array_put(dir->tr);
1178
1179 /*
1180 * If dir->subsystem is NULL, then this is a temporary
1181 * descriptor that was made for a trace_array to enable
1182 * all subsystems.
1183 */
1184 if (dir->subsystem)
1185 put_system(dir);
1186 else
1187 kfree(dir);
1188
1189 return 0;
1190 }
1191
1192 static ssize_t
1193 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1194 loff_t *ppos)
1195 {
1196 struct ftrace_subsystem_dir *dir = filp->private_data;
1197 struct event_subsystem *system = dir->subsystem;
1198 struct trace_seq *s;
1199 int r;
1200
1201 if (*ppos)
1202 return 0;
1203
1204 s = kmalloc(sizeof(*s), GFP_KERNEL);
1205 if (!s)
1206 return -ENOMEM;
1207
1208 trace_seq_init(s);
1209
1210 print_subsystem_event_filter(system, s);
1211 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1212
1213 kfree(s);
1214
1215 return r;
1216 }
1217
1218 static ssize_t
1219 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1220 loff_t *ppos)
1221 {
1222 struct ftrace_subsystem_dir *dir = filp->private_data;
1223 char *buf;
1224 int err;
1225
1226 if (cnt >= PAGE_SIZE)
1227 return -EINVAL;
1228
1229 buf = (char *)__get_free_page(GFP_TEMPORARY);
1230 if (!buf)
1231 return -ENOMEM;
1232
1233 if (copy_from_user(buf, ubuf, cnt)) {
1234 free_page((unsigned long) buf);
1235 return -EFAULT;
1236 }
1237 buf[cnt] = '\0';
1238
1239 err = apply_subsystem_event_filter(dir, buf);
1240 free_page((unsigned long) buf);
1241 if (err < 0)
1242 return err;
1243
1244 *ppos += cnt;
1245
1246 return cnt;
1247 }
1248
1249 static ssize_t
1250 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1251 {
1252 int (*func)(struct trace_seq *s) = filp->private_data;
1253 struct trace_seq *s;
1254 int r;
1255
1256 if (*ppos)
1257 return 0;
1258
1259 s = kmalloc(sizeof(*s), GFP_KERNEL);
1260 if (!s)
1261 return -ENOMEM;
1262
1263 trace_seq_init(s);
1264
1265 func(s);
1266 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1267
1268 kfree(s);
1269
1270 return r;
1271 }
1272
1273 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1274 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1275 static int ftrace_event_release(struct inode *inode, struct file *file);
1276
1277 static const struct seq_operations show_event_seq_ops = {
1278 .start = t_start,
1279 .next = t_next,
1280 .show = t_show,
1281 .stop = t_stop,
1282 };
1283
1284 static const struct seq_operations show_set_event_seq_ops = {
1285 .start = s_start,
1286 .next = s_next,
1287 .show = t_show,
1288 .stop = t_stop,
1289 };
1290
1291 static const struct file_operations ftrace_avail_fops = {
1292 .open = ftrace_event_avail_open,
1293 .read = seq_read,
1294 .llseek = seq_lseek,
1295 .release = seq_release,
1296 };
1297
1298 static const struct file_operations ftrace_set_event_fops = {
1299 .open = ftrace_event_set_open,
1300 .read = seq_read,
1301 .write = ftrace_event_write,
1302 .llseek = seq_lseek,
1303 .release = ftrace_event_release,
1304 };
1305
1306 static const struct file_operations ftrace_enable_fops = {
1307 .open = tracing_open_generic,
1308 .read = event_enable_read,
1309 .write = event_enable_write,
1310 .llseek = default_llseek,
1311 };
1312
1313 static const struct file_operations ftrace_event_format_fops = {
1314 .open = trace_format_open,
1315 .read = seq_read,
1316 .llseek = seq_lseek,
1317 .release = seq_release,
1318 };
1319
1320 static const struct file_operations ftrace_event_id_fops = {
1321 .read = event_id_read,
1322 .llseek = default_llseek,
1323 };
1324
1325 static const struct file_operations ftrace_event_filter_fops = {
1326 .open = tracing_open_generic,
1327 .read = event_filter_read,
1328 .write = event_filter_write,
1329 .llseek = default_llseek,
1330 };
1331
1332 static const struct file_operations ftrace_subsystem_filter_fops = {
1333 .open = subsystem_open,
1334 .read = subsystem_filter_read,
1335 .write = subsystem_filter_write,
1336 .llseek = default_llseek,
1337 .release = subsystem_release,
1338 };
1339
1340 static const struct file_operations ftrace_system_enable_fops = {
1341 .open = subsystem_open,
1342 .read = system_enable_read,
1343 .write = system_enable_write,
1344 .llseek = default_llseek,
1345 .release = subsystem_release,
1346 };
1347
1348 static const struct file_operations ftrace_tr_enable_fops = {
1349 .open = system_tr_open,
1350 .read = system_enable_read,
1351 .write = system_enable_write,
1352 .llseek = default_llseek,
1353 .release = subsystem_release,
1354 };
1355
1356 static const struct file_operations ftrace_show_header_fops = {
1357 .open = tracing_open_generic,
1358 .read = show_header,
1359 .llseek = default_llseek,
1360 };
1361
1362 static int
1363 ftrace_event_open(struct inode *inode, struct file *file,
1364 const struct seq_operations *seq_ops)
1365 {
1366 struct seq_file *m;
1367 int ret;
1368
1369 ret = seq_open(file, seq_ops);
1370 if (ret < 0)
1371 return ret;
1372 m = file->private_data;
1373 /* copy tr over to seq ops */
1374 m->private = inode->i_private;
1375
1376 return ret;
1377 }
1378
1379 static int ftrace_event_release(struct inode *inode, struct file *file)
1380 {
1381 struct trace_array *tr = inode->i_private;
1382
1383 trace_array_put(tr);
1384
1385 return seq_release(inode, file);
1386 }
1387
1388 static int
1389 ftrace_event_avail_open(struct inode *inode, struct file *file)
1390 {
1391 const struct seq_operations *seq_ops = &show_event_seq_ops;
1392
1393 return ftrace_event_open(inode, file, seq_ops);
1394 }
1395
1396 static int
1397 ftrace_event_set_open(struct inode *inode, struct file *file)
1398 {
1399 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1400 struct trace_array *tr = inode->i_private;
1401 int ret;
1402
1403 if (trace_array_get(tr) < 0)
1404 return -ENODEV;
1405
1406 if ((file->f_mode & FMODE_WRITE) &&
1407 (file->f_flags & O_TRUNC))
1408 ftrace_clear_events(tr);
1409
1410 ret = ftrace_event_open(inode, file, seq_ops);
1411 if (ret < 0)
1412 trace_array_put(tr);
1413 return ret;
1414 }
1415
1416 static struct event_subsystem *
1417 create_new_subsystem(const char *name)
1418 {
1419 struct event_subsystem *system;
1420
1421 /* need to create new entry */
1422 system = kmalloc(sizeof(*system), GFP_KERNEL);
1423 if (!system)
1424 return NULL;
1425
1426 system->ref_count = 1;
1427
1428 /* Only allocate if dynamic (kprobes and modules) */
1429 if (!core_kernel_data((unsigned long)name)) {
1430 system->ref_count |= SYSTEM_FL_FREE_NAME;
1431 system->name = kstrdup(name, GFP_KERNEL);
1432 if (!system->name)
1433 goto out_free;
1434 } else
1435 system->name = name;
1436
1437 system->filter = NULL;
1438
1439 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1440 if (!system->filter)
1441 goto out_free;
1442
1443 list_add(&system->list, &event_subsystems);
1444
1445 return system;
1446
1447 out_free:
1448 if (system->ref_count & SYSTEM_FL_FREE_NAME)
1449 kfree(system->name);
1450 kfree(system);
1451 return NULL;
1452 }
1453
1454 static struct dentry *
1455 event_subsystem_dir(struct trace_array *tr, const char *name,
1456 struct ftrace_event_file *file, struct dentry *parent)
1457 {
1458 struct ftrace_subsystem_dir *dir;
1459 struct event_subsystem *system;
1460 struct dentry *entry;
1461
1462 /* First see if we did not already create this dir */
1463 list_for_each_entry(dir, &tr->systems, list) {
1464 system = dir->subsystem;
1465 if (strcmp(system->name, name) == 0) {
1466 dir->nr_events++;
1467 file->system = dir;
1468 return dir->entry;
1469 }
1470 }
1471
1472 /* Now see if the system itself exists. */
1473 list_for_each_entry(system, &event_subsystems, list) {
1474 if (strcmp(system->name, name) == 0)
1475 break;
1476 }
1477 /* Reset system variable when not found */
1478 if (&system->list == &event_subsystems)
1479 system = NULL;
1480
1481 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1482 if (!dir)
1483 goto out_fail;
1484
1485 if (!system) {
1486 system = create_new_subsystem(name);
1487 if (!system)
1488 goto out_free;
1489 } else
1490 __get_system(system);
1491
1492 dir->entry = debugfs_create_dir(name, parent);
1493 if (!dir->entry) {
1494 pr_warning("Failed to create system directory %s\n", name);
1495 __put_system(system);
1496 goto out_free;
1497 }
1498
1499 dir->tr = tr;
1500 dir->ref_count = 1;
1501 dir->nr_events = 1;
1502 dir->subsystem = system;
1503 file->system = dir;
1504
1505 entry = debugfs_create_file("filter", 0644, dir->entry, dir,
1506 &ftrace_subsystem_filter_fops);
1507 if (!entry) {
1508 kfree(system->filter);
1509 system->filter = NULL;
1510 pr_warning("Could not create debugfs '%s/filter' entry\n", name);
1511 }
1512
1513 trace_create_file("enable", 0644, dir->entry, dir,
1514 &ftrace_system_enable_fops);
1515
1516 list_add(&dir->list, &tr->systems);
1517
1518 return dir->entry;
1519
1520 out_free:
1521 kfree(dir);
1522 out_fail:
1523 /* Only print this message if failed on memory allocation */
1524 if (!dir || !system)
1525 pr_warning("No memory to create event subsystem %s\n",
1526 name);
1527 return NULL;
1528 }
1529
1530 static int
1531 event_create_dir(struct dentry *parent, struct ftrace_event_file *file)
1532 {
1533 struct ftrace_event_call *call = file->event_call;
1534 struct trace_array *tr = file->tr;
1535 struct list_head *head;
1536 struct dentry *d_events;
1537 const char *name;
1538 int ret;
1539
1540 /*
1541 * If the trace point header did not define TRACE_SYSTEM
1542 * then the system would be called "TRACE_SYSTEM".
1543 */
1544 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1545 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1546 if (!d_events)
1547 return -ENOMEM;
1548 } else
1549 d_events = parent;
1550
1551 name = ftrace_event_name(call);
1552 file->dir = debugfs_create_dir(name, d_events);
1553 if (!file->dir) {
1554 pr_warning("Could not create debugfs '%s' directory\n",
1555 name);
1556 return -1;
1557 }
1558
1559 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1560 trace_create_file("enable", 0644, file->dir, file,
1561 &ftrace_enable_fops);
1562
1563 #ifdef CONFIG_PERF_EVENTS
1564 if (call->event.type && call->class->reg)
1565 trace_create_file("id", 0444, file->dir,
1566 (void *)(long)call->event.type,
1567 &ftrace_event_id_fops);
1568 #endif
1569
1570 /*
1571 * Other events may have the same class. Only update
1572 * the fields if they are not already defined.
1573 */
1574 head = trace_get_fields(call);
1575 if (list_empty(head)) {
1576 ret = call->class->define_fields(call);
1577 if (ret < 0) {
1578 pr_warning("Could not initialize trace point"
1579 " events/%s\n", name);
1580 return -1;
1581 }
1582 }
1583 trace_create_file("filter", 0644, file->dir, file,
1584 &ftrace_event_filter_fops);
1585
1586 trace_create_file("trigger", 0644, file->dir, file,
1587 &event_trigger_fops);
1588
1589 trace_create_file("format", 0444, file->dir, call,
1590 &ftrace_event_format_fops);
1591
1592 return 0;
1593 }
1594
1595 static void remove_event_from_tracers(struct ftrace_event_call *call)
1596 {
1597 struct ftrace_event_file *file;
1598 struct trace_array *tr;
1599
1600 do_for_each_event_file_safe(tr, file) {
1601 if (file->event_call != call)
1602 continue;
1603
1604 remove_event_file_dir(file);
1605 /*
1606 * The do_for_each_event_file_safe() is
1607 * a double loop. After finding the call for this
1608 * trace_array, we use break to jump to the next
1609 * trace_array.
1610 */
1611 break;
1612 } while_for_each_event_file();
1613 }
1614
1615 static void event_remove(struct ftrace_event_call *call)
1616 {
1617 struct trace_array *tr;
1618 struct ftrace_event_file *file;
1619
1620 do_for_each_event_file(tr, file) {
1621 if (file->event_call != call)
1622 continue;
1623 ftrace_event_enable_disable(file, 0);
1624 destroy_preds(file);
1625 /*
1626 * The do_for_each_event_file() is
1627 * a double loop. After finding the call for this
1628 * trace_array, we use break to jump to the next
1629 * trace_array.
1630 */
1631 break;
1632 } while_for_each_event_file();
1633
1634 if (call->event.funcs)
1635 __unregister_ftrace_event(&call->event);
1636 remove_event_from_tracers(call);
1637 list_del(&call->list);
1638 }
1639
1640 static int event_init(struct ftrace_event_call *call)
1641 {
1642 int ret = 0;
1643 const char *name;
1644
1645 name = ftrace_event_name(call);
1646 if (WARN_ON(!name))
1647 return -EINVAL;
1648
1649 if (call->class->raw_init) {
1650 ret = call->class->raw_init(call);
1651 if (ret < 0 && ret != -ENOSYS)
1652 pr_warn("Could not initialize trace events/%s\n",
1653 name);
1654 }
1655
1656 return ret;
1657 }
1658
1659 static int
1660 __register_event(struct ftrace_event_call *call, struct module *mod)
1661 {
1662 int ret;
1663
1664 ret = event_init(call);
1665 if (ret < 0)
1666 return ret;
1667
1668 list_add(&call->list, &ftrace_events);
1669 call->mod = mod;
1670
1671 return 0;
1672 }
1673
1674 static struct ftrace_event_file *
1675 trace_create_new_event(struct ftrace_event_call *call,
1676 struct trace_array *tr)
1677 {
1678 struct ftrace_event_file *file;
1679
1680 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
1681 if (!file)
1682 return NULL;
1683
1684 file->event_call = call;
1685 file->tr = tr;
1686 atomic_set(&file->sm_ref, 0);
1687 atomic_set(&file->tm_ref, 0);
1688 INIT_LIST_HEAD(&file->triggers);
1689 list_add(&file->list, &tr->events);
1690
1691 return file;
1692 }
1693
1694 /* Add an event to a trace directory */
1695 static int
1696 __trace_add_new_event(struct ftrace_event_call *call, struct trace_array *tr)
1697 {
1698 struct ftrace_event_file *file;
1699
1700 file = trace_create_new_event(call, tr);
1701 if (!file)
1702 return -ENOMEM;
1703
1704 return event_create_dir(tr->event_dir, file);
1705 }
1706
1707 /*
1708 * Just create a decriptor for early init. A descriptor is required
1709 * for enabling events at boot. We want to enable events before
1710 * the filesystem is initialized.
1711 */
1712 static __init int
1713 __trace_early_add_new_event(struct ftrace_event_call *call,
1714 struct trace_array *tr)
1715 {
1716 struct ftrace_event_file *file;
1717
1718 file = trace_create_new_event(call, tr);
1719 if (!file)
1720 return -ENOMEM;
1721
1722 return 0;
1723 }
1724
1725 struct ftrace_module_file_ops;
1726 static void __add_event_to_tracers(struct ftrace_event_call *call);
1727
1728 /* Add an additional event_call dynamically */
1729 int trace_add_event_call(struct ftrace_event_call *call)
1730 {
1731 int ret;
1732 mutex_lock(&trace_types_lock);
1733 mutex_lock(&event_mutex);
1734
1735 ret = __register_event(call, NULL);
1736 if (ret >= 0)
1737 __add_event_to_tracers(call);
1738
1739 mutex_unlock(&event_mutex);
1740 mutex_unlock(&trace_types_lock);
1741 return ret;
1742 }
1743
1744 /*
1745 * Must be called under locking of trace_types_lock, event_mutex and
1746 * trace_event_sem.
1747 */
1748 static void __trace_remove_event_call(struct ftrace_event_call *call)
1749 {
1750 event_remove(call);
1751 trace_destroy_fields(call);
1752 destroy_call_preds(call);
1753 }
1754
1755 static int probe_remove_event_call(struct ftrace_event_call *call)
1756 {
1757 struct trace_array *tr;
1758 struct ftrace_event_file *file;
1759
1760 #ifdef CONFIG_PERF_EVENTS
1761 if (call->perf_refcount)
1762 return -EBUSY;
1763 #endif
1764 do_for_each_event_file(tr, file) {
1765 if (file->event_call != call)
1766 continue;
1767 /*
1768 * We can't rely on ftrace_event_enable_disable(enable => 0)
1769 * we are going to do, FTRACE_EVENT_FL_SOFT_MODE can suppress
1770 * TRACE_REG_UNREGISTER.
1771 */
1772 if (file->flags & FTRACE_EVENT_FL_ENABLED)
1773 return -EBUSY;
1774 /*
1775 * The do_for_each_event_file_safe() is
1776 * a double loop. After finding the call for this
1777 * trace_array, we use break to jump to the next
1778 * trace_array.
1779 */
1780 break;
1781 } while_for_each_event_file();
1782
1783 __trace_remove_event_call(call);
1784
1785 return 0;
1786 }
1787
1788 /* Remove an event_call */
1789 int trace_remove_event_call(struct ftrace_event_call *call)
1790 {
1791 int ret;
1792
1793 mutex_lock(&trace_types_lock);
1794 mutex_lock(&event_mutex);
1795 down_write(&trace_event_sem);
1796 ret = probe_remove_event_call(call);
1797 up_write(&trace_event_sem);
1798 mutex_unlock(&event_mutex);
1799 mutex_unlock(&trace_types_lock);
1800
1801 return ret;
1802 }
1803
1804 #define for_each_event(event, start, end) \
1805 for (event = start; \
1806 (unsigned long)event < (unsigned long)end; \
1807 event++)
1808
1809 #ifdef CONFIG_MODULES
1810
1811 static void trace_module_add_events(struct module *mod)
1812 {
1813 struct ftrace_event_call **call, **start, **end;
1814
1815 if (!mod->num_trace_events)
1816 return;
1817
1818 /* Don't add infrastructure for mods without tracepoints */
1819 if (trace_module_has_bad_taint(mod)) {
1820 pr_err("%s: module has bad taint, not creating trace events\n",
1821 mod->name);
1822 return;
1823 }
1824
1825 start = mod->trace_events;
1826 end = mod->trace_events + mod->num_trace_events;
1827
1828 for_each_event(call, start, end) {
1829 __register_event(*call, mod);
1830 __add_event_to_tracers(*call);
1831 }
1832 }
1833
1834 static void trace_module_remove_events(struct module *mod)
1835 {
1836 struct ftrace_event_call *call, *p;
1837 bool clear_trace = false;
1838
1839 down_write(&trace_event_sem);
1840 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1841 if (call->mod == mod) {
1842 if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
1843 clear_trace = true;
1844 __trace_remove_event_call(call);
1845 }
1846 }
1847 up_write(&trace_event_sem);
1848
1849 /*
1850 * It is safest to reset the ring buffer if the module being unloaded
1851 * registered any events that were used. The only worry is if
1852 * a new module gets loaded, and takes on the same id as the events
1853 * of this module. When printing out the buffer, traced events left
1854 * over from this module may be passed to the new module events and
1855 * unexpected results may occur.
1856 */
1857 if (clear_trace)
1858 tracing_reset_all_online_cpus();
1859 }
1860
1861 static int trace_module_notify(struct notifier_block *self,
1862 unsigned long val, void *data)
1863 {
1864 struct module *mod = data;
1865
1866 mutex_lock(&trace_types_lock);
1867 mutex_lock(&event_mutex);
1868 switch (val) {
1869 case MODULE_STATE_COMING:
1870 trace_module_add_events(mod);
1871 break;
1872 case MODULE_STATE_GOING:
1873 trace_module_remove_events(mod);
1874 break;
1875 }
1876 mutex_unlock(&event_mutex);
1877 mutex_unlock(&trace_types_lock);
1878
1879 return 0;
1880 }
1881
1882 static struct notifier_block trace_module_nb = {
1883 .notifier_call = trace_module_notify,
1884 .priority = 0,
1885 };
1886 #endif /* CONFIG_MODULES */
1887
1888 /* Create a new event directory structure for a trace directory. */
1889 static void
1890 __trace_add_event_dirs(struct trace_array *tr)
1891 {
1892 struct ftrace_event_call *call;
1893 int ret;
1894
1895 list_for_each_entry(call, &ftrace_events, list) {
1896 ret = __trace_add_new_event(call, tr);
1897 if (ret < 0)
1898 pr_warning("Could not create directory for event %s\n",
1899 ftrace_event_name(call));
1900 }
1901 }
1902
1903 struct ftrace_event_file *
1904 find_event_file(struct trace_array *tr, const char *system, const char *event)
1905 {
1906 struct ftrace_event_file *file;
1907 struct ftrace_event_call *call;
1908 const char *name;
1909
1910 list_for_each_entry(file, &tr->events, list) {
1911
1912 call = file->event_call;
1913 name = ftrace_event_name(call);
1914
1915 if (!name || !call->class || !call->class->reg)
1916 continue;
1917
1918 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1919 continue;
1920
1921 if (strcmp(event, name) == 0 &&
1922 strcmp(system, call->class->system) == 0)
1923 return file;
1924 }
1925 return NULL;
1926 }
1927
1928 #ifdef CONFIG_DYNAMIC_FTRACE
1929
1930 /* Avoid typos */
1931 #define ENABLE_EVENT_STR "enable_event"
1932 #define DISABLE_EVENT_STR "disable_event"
1933
1934 struct event_probe_data {
1935 struct ftrace_event_file *file;
1936 unsigned long count;
1937 int ref;
1938 bool enable;
1939 };
1940
1941 static void
1942 event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1943 {
1944 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1945 struct event_probe_data *data = *pdata;
1946
1947 if (!data)
1948 return;
1949
1950 if (data->enable)
1951 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1952 else
1953 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1954 }
1955
1956 static void
1957 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1958 {
1959 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1960 struct event_probe_data *data = *pdata;
1961
1962 if (!data)
1963 return;
1964
1965 if (!data->count)
1966 return;
1967
1968 /* Skip if the event is in a state we want to switch to */
1969 if (data->enable == !(data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
1970 return;
1971
1972 if (data->count != -1)
1973 (data->count)--;
1974
1975 event_enable_probe(ip, parent_ip, _data);
1976 }
1977
1978 static int
1979 event_enable_print(struct seq_file *m, unsigned long ip,
1980 struct ftrace_probe_ops *ops, void *_data)
1981 {
1982 struct event_probe_data *data = _data;
1983
1984 seq_printf(m, "%ps:", (void *)ip);
1985
1986 seq_printf(m, "%s:%s:%s",
1987 data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
1988 data->file->event_call->class->system,
1989 ftrace_event_name(data->file->event_call));
1990
1991 if (data->count == -1)
1992 seq_printf(m, ":unlimited\n");
1993 else
1994 seq_printf(m, ":count=%ld\n", data->count);
1995
1996 return 0;
1997 }
1998
1999 static int
2000 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
2001 void **_data)
2002 {
2003 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2004 struct event_probe_data *data = *pdata;
2005
2006 data->ref++;
2007 return 0;
2008 }
2009
2010 static void
2011 event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
2012 void **_data)
2013 {
2014 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2015 struct event_probe_data *data = *pdata;
2016
2017 if (WARN_ON_ONCE(data->ref <= 0))
2018 return;
2019
2020 data->ref--;
2021 if (!data->ref) {
2022 /* Remove the SOFT_MODE flag */
2023 __ftrace_event_enable_disable(data->file, 0, 1);
2024 module_put(data->file->event_call->mod);
2025 kfree(data);
2026 }
2027 *pdata = NULL;
2028 }
2029
2030 static struct ftrace_probe_ops event_enable_probe_ops = {
2031 .func = event_enable_probe,
2032 .print = event_enable_print,
2033 .init = event_enable_init,
2034 .free = event_enable_free,
2035 };
2036
2037 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2038 .func = event_enable_count_probe,
2039 .print = event_enable_print,
2040 .init = event_enable_init,
2041 .free = event_enable_free,
2042 };
2043
2044 static struct ftrace_probe_ops event_disable_probe_ops = {
2045 .func = event_enable_probe,
2046 .print = event_enable_print,
2047 .init = event_enable_init,
2048 .free = event_enable_free,
2049 };
2050
2051 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2052 .func = event_enable_count_probe,
2053 .print = event_enable_print,
2054 .init = event_enable_init,
2055 .free = event_enable_free,
2056 };
2057
2058 static int
2059 event_enable_func(struct ftrace_hash *hash,
2060 char *glob, char *cmd, char *param, int enabled)
2061 {
2062 struct trace_array *tr = top_trace_array();
2063 struct ftrace_event_file *file;
2064 struct ftrace_probe_ops *ops;
2065 struct event_probe_data *data;
2066 const char *system;
2067 const char *event;
2068 char *number;
2069 bool enable;
2070 int ret;
2071
2072 if (!tr)
2073 return -ENODEV;
2074
2075 /* hash funcs only work with set_ftrace_filter */
2076 if (!enabled || !param)
2077 return -EINVAL;
2078
2079 system = strsep(&param, ":");
2080 if (!param)
2081 return -EINVAL;
2082
2083 event = strsep(&param, ":");
2084
2085 mutex_lock(&event_mutex);
2086
2087 ret = -EINVAL;
2088 file = find_event_file(tr, system, event);
2089 if (!file)
2090 goto out;
2091
2092 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2093
2094 if (enable)
2095 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2096 else
2097 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2098
2099 if (glob[0] == '!') {
2100 unregister_ftrace_function_probe_func(glob+1, ops);
2101 ret = 0;
2102 goto out;
2103 }
2104
2105 ret = -ENOMEM;
2106 data = kzalloc(sizeof(*data), GFP_KERNEL);
2107 if (!data)
2108 goto out;
2109
2110 data->enable = enable;
2111 data->count = -1;
2112 data->file = file;
2113
2114 if (!param)
2115 goto out_reg;
2116
2117 number = strsep(&param, ":");
2118
2119 ret = -EINVAL;
2120 if (!strlen(number))
2121 goto out_free;
2122
2123 /*
2124 * We use the callback data field (which is a pointer)
2125 * as our counter.
2126 */
2127 ret = kstrtoul(number, 0, &data->count);
2128 if (ret)
2129 goto out_free;
2130
2131 out_reg:
2132 /* Don't let event modules unload while probe registered */
2133 ret = try_module_get(file->event_call->mod);
2134 if (!ret) {
2135 ret = -EBUSY;
2136 goto out_free;
2137 }
2138
2139 ret = __ftrace_event_enable_disable(file, 1, 1);
2140 if (ret < 0)
2141 goto out_put;
2142 ret = register_ftrace_function_probe(glob, ops, data);
2143 /*
2144 * The above returns on success the # of functions enabled,
2145 * but if it didn't find any functions it returns zero.
2146 * Consider no functions a failure too.
2147 */
2148 if (!ret) {
2149 ret = -ENOENT;
2150 goto out_disable;
2151 } else if (ret < 0)
2152 goto out_disable;
2153 /* Just return zero, not the number of enabled functions */
2154 ret = 0;
2155 out:
2156 mutex_unlock(&event_mutex);
2157 return ret;
2158
2159 out_disable:
2160 __ftrace_event_enable_disable(file, 0, 1);
2161 out_put:
2162 module_put(file->event_call->mod);
2163 out_free:
2164 kfree(data);
2165 goto out;
2166 }
2167
2168 static struct ftrace_func_command event_enable_cmd = {
2169 .name = ENABLE_EVENT_STR,
2170 .func = event_enable_func,
2171 };
2172
2173 static struct ftrace_func_command event_disable_cmd = {
2174 .name = DISABLE_EVENT_STR,
2175 .func = event_enable_func,
2176 };
2177
2178 static __init int register_event_cmds(void)
2179 {
2180 int ret;
2181
2182 ret = register_ftrace_command(&event_enable_cmd);
2183 if (WARN_ON(ret < 0))
2184 return ret;
2185 ret = register_ftrace_command(&event_disable_cmd);
2186 if (WARN_ON(ret < 0))
2187 unregister_ftrace_command(&event_enable_cmd);
2188 return ret;
2189 }
2190 #else
2191 static inline int register_event_cmds(void) { return 0; }
2192 #endif /* CONFIG_DYNAMIC_FTRACE */
2193
2194 /*
2195 * The top level array has already had its ftrace_event_file
2196 * descriptors created in order to allow for early events to
2197 * be recorded. This function is called after the debugfs has been
2198 * initialized, and we now have to create the files associated
2199 * to the events.
2200 */
2201 static __init void
2202 __trace_early_add_event_dirs(struct trace_array *tr)
2203 {
2204 struct ftrace_event_file *file;
2205 int ret;
2206
2207
2208 list_for_each_entry(file, &tr->events, list) {
2209 ret = event_create_dir(tr->event_dir, file);
2210 if (ret < 0)
2211 pr_warning("Could not create directory for event %s\n",
2212 ftrace_event_name(file->event_call));
2213 }
2214 }
2215
2216 /*
2217 * For early boot up, the top trace array requires to have
2218 * a list of events that can be enabled. This must be done before
2219 * the filesystem is set up in order to allow events to be traced
2220 * early.
2221 */
2222 static __init void
2223 __trace_early_add_events(struct trace_array *tr)
2224 {
2225 struct ftrace_event_call *call;
2226 int ret;
2227
2228 list_for_each_entry(call, &ftrace_events, list) {
2229 /* Early boot up should not have any modules loaded */
2230 if (WARN_ON_ONCE(call->mod))
2231 continue;
2232
2233 ret = __trace_early_add_new_event(call, tr);
2234 if (ret < 0)
2235 pr_warning("Could not create early event %s\n",
2236 ftrace_event_name(call));
2237 }
2238 }
2239
2240 /* Remove the event directory structure for a trace directory. */
2241 static void
2242 __trace_remove_event_dirs(struct trace_array *tr)
2243 {
2244 struct ftrace_event_file *file, *next;
2245
2246 list_for_each_entry_safe(file, next, &tr->events, list)
2247 remove_event_file_dir(file);
2248 }
2249
2250 static void __add_event_to_tracers(struct ftrace_event_call *call)
2251 {
2252 struct trace_array *tr;
2253
2254 list_for_each_entry(tr, &ftrace_trace_arrays, list)
2255 __trace_add_new_event(call, tr);
2256 }
2257
2258 extern struct ftrace_event_call *__start_ftrace_events[];
2259 extern struct ftrace_event_call *__stop_ftrace_events[];
2260
2261 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2262
2263 static __init int setup_trace_event(char *str)
2264 {
2265 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2266 ring_buffer_expanded = true;
2267 tracing_selftest_disabled = true;
2268
2269 return 1;
2270 }
2271 __setup("trace_event=", setup_trace_event);
2272
2273 /* Expects to have event_mutex held when called */
2274 static int
2275 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2276 {
2277 struct dentry *d_events;
2278 struct dentry *entry;
2279
2280 entry = debugfs_create_file("set_event", 0644, parent,
2281 tr, &ftrace_set_event_fops);
2282 if (!entry) {
2283 pr_warning("Could not create debugfs 'set_event' entry\n");
2284 return -ENOMEM;
2285 }
2286
2287 d_events = debugfs_create_dir("events", parent);
2288 if (!d_events) {
2289 pr_warning("Could not create debugfs 'events' directory\n");
2290 return -ENOMEM;
2291 }
2292
2293 /* ring buffer internal formats */
2294 trace_create_file("header_page", 0444, d_events,
2295 ring_buffer_print_page_header,
2296 &ftrace_show_header_fops);
2297
2298 trace_create_file("header_event", 0444, d_events,
2299 ring_buffer_print_entry_header,
2300 &ftrace_show_header_fops);
2301
2302 trace_create_file("enable", 0644, d_events,
2303 tr, &ftrace_tr_enable_fops);
2304
2305 tr->event_dir = d_events;
2306
2307 return 0;
2308 }
2309
2310 /**
2311 * event_trace_add_tracer - add a instance of a trace_array to events
2312 * @parent: The parent dentry to place the files/directories for events in
2313 * @tr: The trace array associated with these events
2314 *
2315 * When a new instance is created, it needs to set up its events
2316 * directory, as well as other files associated with events. It also
2317 * creates the event hierachry in the @parent/events directory.
2318 *
2319 * Returns 0 on success.
2320 */
2321 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2322 {
2323 int ret;
2324
2325 mutex_lock(&event_mutex);
2326
2327 ret = create_event_toplevel_files(parent, tr);
2328 if (ret)
2329 goto out_unlock;
2330
2331 down_write(&trace_event_sem);
2332 __trace_add_event_dirs(tr);
2333 up_write(&trace_event_sem);
2334
2335 out_unlock:
2336 mutex_unlock(&event_mutex);
2337
2338 return ret;
2339 }
2340
2341 /*
2342 * The top trace array already had its file descriptors created.
2343 * Now the files themselves need to be created.
2344 */
2345 static __init int
2346 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2347 {
2348 int ret;
2349
2350 mutex_lock(&event_mutex);
2351
2352 ret = create_event_toplevel_files(parent, tr);
2353 if (ret)
2354 goto out_unlock;
2355
2356 down_write(&trace_event_sem);
2357 __trace_early_add_event_dirs(tr);
2358 up_write(&trace_event_sem);
2359
2360 out_unlock:
2361 mutex_unlock(&event_mutex);
2362
2363 return ret;
2364 }
2365
2366 int event_trace_del_tracer(struct trace_array *tr)
2367 {
2368 mutex_lock(&event_mutex);
2369
2370 /* Disable any event triggers and associated soft-disabled events */
2371 clear_event_triggers(tr);
2372
2373 /* Disable any running events */
2374 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
2375
2376 /* Access to events are within rcu_read_lock_sched() */
2377 synchronize_sched();
2378
2379 down_write(&trace_event_sem);
2380 __trace_remove_event_dirs(tr);
2381 debugfs_remove_recursive(tr->event_dir);
2382 up_write(&trace_event_sem);
2383
2384 tr->event_dir = NULL;
2385
2386 mutex_unlock(&event_mutex);
2387
2388 return 0;
2389 }
2390
2391 static __init int event_trace_memsetup(void)
2392 {
2393 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
2394 file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC);
2395 return 0;
2396 }
2397
2398 static __init int event_trace_enable(void)
2399 {
2400 struct trace_array *tr = top_trace_array();
2401 struct ftrace_event_call **iter, *call;
2402 char *buf = bootup_event_buf;
2403 char *token;
2404 int ret;
2405
2406 if (!tr)
2407 return -ENODEV;
2408
2409 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
2410
2411 call = *iter;
2412 ret = event_init(call);
2413 if (!ret)
2414 list_add(&call->list, &ftrace_events);
2415 }
2416
2417 /*
2418 * We need the top trace array to have a working set of trace
2419 * points at early init, before the debug files and directories
2420 * are created. Create the file entries now, and attach them
2421 * to the actual file dentries later.
2422 */
2423 __trace_early_add_events(tr);
2424
2425 while (true) {
2426 token = strsep(&buf, ",");
2427
2428 if (!token)
2429 break;
2430 if (!*token)
2431 continue;
2432
2433 ret = ftrace_set_clr_event(tr, token, 1);
2434 if (ret)
2435 pr_warn("Failed to enable trace event: %s\n", token);
2436 }
2437
2438 trace_printk_start_comm();
2439
2440 register_event_cmds();
2441
2442 register_trigger_cmds();
2443
2444 return 0;
2445 }
2446
2447 static __init int event_trace_init(void)
2448 {
2449 struct trace_array *tr;
2450 struct dentry *d_tracer;
2451 struct dentry *entry;
2452 int ret;
2453
2454 tr = top_trace_array();
2455 if (!tr)
2456 return -ENODEV;
2457
2458 d_tracer = tracing_init_dentry();
2459 if (!d_tracer)
2460 return 0;
2461
2462 entry = debugfs_create_file("available_events", 0444, d_tracer,
2463 tr, &ftrace_avail_fops);
2464 if (!entry)
2465 pr_warning("Could not create debugfs "
2466 "'available_events' entry\n");
2467
2468 if (trace_define_common_fields())
2469 pr_warning("tracing: Failed to allocate common fields");
2470
2471 ret = early_event_add_tracer(d_tracer, tr);
2472 if (ret)
2473 return ret;
2474
2475 #ifdef CONFIG_MODULES
2476 ret = register_module_notifier(&trace_module_nb);
2477 if (ret)
2478 pr_warning("Failed to register trace events module notifier\n");
2479 #endif
2480 return 0;
2481 }
2482 early_initcall(event_trace_memsetup);
2483 core_initcall(event_trace_enable);
2484 fs_initcall(event_trace_init);
2485
2486 #ifdef CONFIG_FTRACE_STARTUP_TEST
2487
2488 static DEFINE_SPINLOCK(test_spinlock);
2489 static DEFINE_SPINLOCK(test_spinlock_irq);
2490 static DEFINE_MUTEX(test_mutex);
2491
2492 static __init void test_work(struct work_struct *dummy)
2493 {
2494 spin_lock(&test_spinlock);
2495 spin_lock_irq(&test_spinlock_irq);
2496 udelay(1);
2497 spin_unlock_irq(&test_spinlock_irq);
2498 spin_unlock(&test_spinlock);
2499
2500 mutex_lock(&test_mutex);
2501 msleep(1);
2502 mutex_unlock(&test_mutex);
2503 }
2504
2505 static __init int event_test_thread(void *unused)
2506 {
2507 void *test_malloc;
2508
2509 test_malloc = kmalloc(1234, GFP_KERNEL);
2510 if (!test_malloc)
2511 pr_info("failed to kmalloc\n");
2512
2513 schedule_on_each_cpu(test_work);
2514
2515 kfree(test_malloc);
2516
2517 set_current_state(TASK_INTERRUPTIBLE);
2518 while (!kthread_should_stop())
2519 schedule();
2520
2521 return 0;
2522 }
2523
2524 /*
2525 * Do various things that may trigger events.
2526 */
2527 static __init void event_test_stuff(void)
2528 {
2529 struct task_struct *test_thread;
2530
2531 test_thread = kthread_run(event_test_thread, NULL, "test-events");
2532 msleep(1);
2533 kthread_stop(test_thread);
2534 }
2535
2536 /*
2537 * For every trace event defined, we will test each trace point separately,
2538 * and then by groups, and finally all trace points.
2539 */
2540 static __init void event_trace_self_tests(void)
2541 {
2542 struct ftrace_subsystem_dir *dir;
2543 struct ftrace_event_file *file;
2544 struct ftrace_event_call *call;
2545 struct event_subsystem *system;
2546 struct trace_array *tr;
2547 int ret;
2548
2549 tr = top_trace_array();
2550 if (!tr)
2551 return;
2552
2553 pr_info("Running tests on trace events:\n");
2554
2555 list_for_each_entry(file, &tr->events, list) {
2556
2557 call = file->event_call;
2558
2559 /* Only test those that have a probe */
2560 if (!call->class || !call->class->probe)
2561 continue;
2562
2563 /*
2564 * Testing syscall events here is pretty useless, but
2565 * we still do it if configured. But this is time consuming.
2566 * What we really need is a user thread to perform the
2567 * syscalls as we test.
2568 */
2569 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
2570 if (call->class->system &&
2571 strcmp(call->class->system, "syscalls") == 0)
2572 continue;
2573 #endif
2574
2575 pr_info("Testing event %s: ", ftrace_event_name(call));
2576
2577 /*
2578 * If an event is already enabled, someone is using
2579 * it and the self test should not be on.
2580 */
2581 if (file->flags & FTRACE_EVENT_FL_ENABLED) {
2582 pr_warning("Enabled event during self test!\n");
2583 WARN_ON_ONCE(1);
2584 continue;
2585 }
2586
2587 ftrace_event_enable_disable(file, 1);
2588 event_test_stuff();
2589 ftrace_event_enable_disable(file, 0);
2590
2591 pr_cont("OK\n");
2592 }
2593
2594 /* Now test at the sub system level */
2595
2596 pr_info("Running tests on trace event systems:\n");
2597
2598 list_for_each_entry(dir, &tr->systems, list) {
2599
2600 system = dir->subsystem;
2601
2602 /* the ftrace system is special, skip it */
2603 if (strcmp(system->name, "ftrace") == 0)
2604 continue;
2605
2606 pr_info("Testing event system %s: ", system->name);
2607
2608 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
2609 if (WARN_ON_ONCE(ret)) {
2610 pr_warning("error enabling system %s\n",
2611 system->name);
2612 continue;
2613 }
2614
2615 event_test_stuff();
2616
2617 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
2618 if (WARN_ON_ONCE(ret)) {
2619 pr_warning("error disabling system %s\n",
2620 system->name);
2621 continue;
2622 }
2623
2624 pr_cont("OK\n");
2625 }
2626
2627 /* Test with all events enabled */
2628
2629 pr_info("Running tests on all trace events:\n");
2630 pr_info("Testing all events: ");
2631
2632 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
2633 if (WARN_ON_ONCE(ret)) {
2634 pr_warning("error enabling all events\n");
2635 return;
2636 }
2637
2638 event_test_stuff();
2639
2640 /* reset sysname */
2641 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
2642 if (WARN_ON_ONCE(ret)) {
2643 pr_warning("error disabling all events\n");
2644 return;
2645 }
2646
2647 pr_cont("OK\n");
2648 }
2649
2650 #ifdef CONFIG_FUNCTION_TRACER
2651
2652 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
2653
2654 static void
2655 function_test_events_call(unsigned long ip, unsigned long parent_ip,
2656 struct ftrace_ops *op, struct pt_regs *pt_regs)
2657 {
2658 struct ring_buffer_event *event;
2659 struct ring_buffer *buffer;
2660 struct ftrace_entry *entry;
2661 unsigned long flags;
2662 long disabled;
2663 int cpu;
2664 int pc;
2665
2666 pc = preempt_count();
2667 preempt_disable_notrace();
2668 cpu = raw_smp_processor_id();
2669 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
2670
2671 if (disabled != 1)
2672 goto out;
2673
2674 local_save_flags(flags);
2675
2676 event = trace_current_buffer_lock_reserve(&buffer,
2677 TRACE_FN, sizeof(*entry),
2678 flags, pc);
2679 if (!event)
2680 goto out;
2681 entry = ring_buffer_event_data(event);
2682 entry->ip = ip;
2683 entry->parent_ip = parent_ip;
2684
2685 trace_buffer_unlock_commit(buffer, event, flags, pc);
2686
2687 out:
2688 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
2689 preempt_enable_notrace();
2690 }
2691
2692 static struct ftrace_ops trace_ops __initdata =
2693 {
2694 .func = function_test_events_call,
2695 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
2696 };
2697
2698 static __init void event_trace_self_test_with_function(void)
2699 {
2700 int ret;
2701 ret = register_ftrace_function(&trace_ops);
2702 if (WARN_ON(ret < 0)) {
2703 pr_info("Failed to enable function tracer for event tests\n");
2704 return;
2705 }
2706 pr_info("Running tests again, along with the function tracer\n");
2707 event_trace_self_tests();
2708 unregister_ftrace_function(&trace_ops);
2709 }
2710 #else
2711 static __init void event_trace_self_test_with_function(void)
2712 {
2713 }
2714 #endif
2715
2716 static __init int event_trace_self_tests_init(void)
2717 {
2718 if (!tracing_selftest_disabled) {
2719 event_trace_self_tests();
2720 event_trace_self_test_with_function();
2721 }
2722
2723 return 0;
2724 }
2725
2726 late_initcall(event_trace_self_tests_init);
2727
2728 #endif
Linux kernel - Deliverables
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