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Merge tag 'ipvs2-for-v3.19' of https://git.kernel.org/pub/scm/linux/kernel/git/horms...
[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 #define pr_fmt(fmt) fmt
12
13 #include <linux/workqueue.h>
14 #include <linux/spinlock.h>
15 #include <linux/kthread.h>
16 #include <linux/debugfs.h>
17 #include <linux/uaccess.h>
18 #include <linux/module.h>
19 #include <linux/ctype.h>
20 #include <linux/slab.h>
21 #include <linux/delay.h>
22
23 #include <asm/setup.h>
24
25 #include "trace_output.h"
26
27 #undef TRACE_SYSTEM
28 #define TRACE_SYSTEM "TRACE_SYSTEM"
29
30 DEFINE_MUTEX(event_mutex);
31
32 LIST_HEAD(ftrace_events);
33 static LIST_HEAD(ftrace_common_fields);
34
35 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
36
37 static struct kmem_cache *field_cachep;
38 static struct kmem_cache *file_cachep;
39
40 #define SYSTEM_FL_FREE_NAME (1 << 31)
41
42 static inline int system_refcount(struct event_subsystem *system)
43 {
44 return system->ref_count & ~SYSTEM_FL_FREE_NAME;
45 }
46
47 static int system_refcount_inc(struct event_subsystem *system)
48 {
49 return (system->ref_count++) & ~SYSTEM_FL_FREE_NAME;
50 }
51
52 static int system_refcount_dec(struct event_subsystem *system)
53 {
54 return (--system->ref_count) & ~SYSTEM_FL_FREE_NAME;
55 }
56
57 /* Double loops, do not use break, only goto's work */
58 #define do_for_each_event_file(tr, file) \
59 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
60 list_for_each_entry(file, &tr->events, list)
61
62 #define do_for_each_event_file_safe(tr, file) \
63 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
64 struct ftrace_event_file *___n; \
65 list_for_each_entry_safe(file, ___n, &tr->events, list)
66
67 #define while_for_each_event_file() \
68 }
69
70 static struct list_head *
71 trace_get_fields(struct ftrace_event_call *event_call)
72 {
73 if (!event_call->class->get_fields)
74 return &event_call->class->fields;
75 return event_call->class->get_fields(event_call);
76 }
77
78 static struct ftrace_event_field *
79 __find_event_field(struct list_head *head, char *name)
80 {
81 struct ftrace_event_field *field;
82
83 list_for_each_entry(field, head, link) {
84 if (!strcmp(field->name, name))
85 return field;
86 }
87
88 return NULL;
89 }
90
91 struct ftrace_event_field *
92 trace_find_event_field(struct ftrace_event_call *call, char *name)
93 {
94 struct ftrace_event_field *field;
95 struct list_head *head;
96
97 field = __find_event_field(&ftrace_common_fields, name);
98 if (field)
99 return field;
100
101 head = trace_get_fields(call);
102 return __find_event_field(head, name);
103 }
104
105 static int __trace_define_field(struct list_head *head, const char *type,
106 const char *name, int offset, int size,
107 int is_signed, int filter_type)
108 {
109 struct ftrace_event_field *field;
110
111 field = kmem_cache_alloc(field_cachep, GFP_TRACE);
112 if (!field)
113 return -ENOMEM;
114
115 field->name = name;
116 field->type = type;
117
118 if (filter_type == FILTER_OTHER)
119 field->filter_type = filter_assign_type(type);
120 else
121 field->filter_type = filter_type;
122
123 field->offset = offset;
124 field->size = size;
125 field->is_signed = is_signed;
126
127 list_add(&field->link, head);
128
129 return 0;
130 }
131
132 int trace_define_field(struct ftrace_event_call *call, const char *type,
133 const char *name, int offset, int size, int is_signed,
134 int filter_type)
135 {
136 struct list_head *head;
137
138 if (WARN_ON(!call->class))
139 return 0;
140
141 head = trace_get_fields(call);
142 return __trace_define_field(head, type, name, offset, size,
143 is_signed, filter_type);
144 }
145 EXPORT_SYMBOL_GPL(trace_define_field);
146
147 #define __common_field(type, item) \
148 ret = __trace_define_field(&ftrace_common_fields, #type, \
149 "common_" #item, \
150 offsetof(typeof(ent), item), \
151 sizeof(ent.item), \
152 is_signed_type(type), FILTER_OTHER); \
153 if (ret) \
154 return ret;
155
156 static int trace_define_common_fields(void)
157 {
158 int ret;
159 struct trace_entry ent;
160
161 __common_field(unsigned short, type);
162 __common_field(unsigned char, flags);
163 __common_field(unsigned char, preempt_count);
164 __common_field(int, pid);
165
166 return ret;
167 }
168
169 static void trace_destroy_fields(struct ftrace_event_call *call)
170 {
171 struct ftrace_event_field *field, *next;
172 struct list_head *head;
173
174 head = trace_get_fields(call);
175 list_for_each_entry_safe(field, next, head, link) {
176 list_del(&field->link);
177 kmem_cache_free(field_cachep, field);
178 }
179 }
180
181 int trace_event_raw_init(struct ftrace_event_call *call)
182 {
183 int id;
184
185 id = register_ftrace_event(&call->event);
186 if (!id)
187 return -ENODEV;
188
189 return 0;
190 }
191 EXPORT_SYMBOL_GPL(trace_event_raw_init);
192
193 void *ftrace_event_buffer_reserve(struct ftrace_event_buffer *fbuffer,
194 struct ftrace_event_file *ftrace_file,
195 unsigned long len)
196 {
197 struct ftrace_event_call *event_call = ftrace_file->event_call;
198
199 local_save_flags(fbuffer->flags);
200 fbuffer->pc = preempt_count();
201 fbuffer->ftrace_file = ftrace_file;
202
203 fbuffer->event =
204 trace_event_buffer_lock_reserve(&fbuffer->buffer, ftrace_file,
205 event_call->event.type, len,
206 fbuffer->flags, fbuffer->pc);
207 if (!fbuffer->event)
208 return NULL;
209
210 fbuffer->entry = ring_buffer_event_data(fbuffer->event);
211 return fbuffer->entry;
212 }
213 EXPORT_SYMBOL_GPL(ftrace_event_buffer_reserve);
214
215 void ftrace_event_buffer_commit(struct ftrace_event_buffer *fbuffer)
216 {
217 event_trigger_unlock_commit(fbuffer->ftrace_file, fbuffer->buffer,
218 fbuffer->event, fbuffer->entry,
219 fbuffer->flags, fbuffer->pc);
220 }
221 EXPORT_SYMBOL_GPL(ftrace_event_buffer_commit);
222
223 int ftrace_event_reg(struct ftrace_event_call *call,
224 enum trace_reg type, void *data)
225 {
226 struct ftrace_event_file *file = data;
227
228 WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
229 switch (type) {
230 case TRACE_REG_REGISTER:
231 return tracepoint_probe_register(call->tp,
232 call->class->probe,
233 file);
234 case TRACE_REG_UNREGISTER:
235 tracepoint_probe_unregister(call->tp,
236 call->class->probe,
237 file);
238 return 0;
239
240 #ifdef CONFIG_PERF_EVENTS
241 case TRACE_REG_PERF_REGISTER:
242 return tracepoint_probe_register(call->tp,
243 call->class->perf_probe,
244 call);
245 case TRACE_REG_PERF_UNREGISTER:
246 tracepoint_probe_unregister(call->tp,
247 call->class->perf_probe,
248 call);
249 return 0;
250 case TRACE_REG_PERF_OPEN:
251 case TRACE_REG_PERF_CLOSE:
252 case TRACE_REG_PERF_ADD:
253 case TRACE_REG_PERF_DEL:
254 return 0;
255 #endif
256 }
257 return 0;
258 }
259 EXPORT_SYMBOL_GPL(ftrace_event_reg);
260
261 void trace_event_enable_cmd_record(bool enable)
262 {
263 struct ftrace_event_file *file;
264 struct trace_array *tr;
265
266 mutex_lock(&event_mutex);
267 do_for_each_event_file(tr, file) {
268
269 if (!(file->flags & FTRACE_EVENT_FL_ENABLED))
270 continue;
271
272 if (enable) {
273 tracing_start_cmdline_record();
274 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
275 } else {
276 tracing_stop_cmdline_record();
277 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
278 }
279 } while_for_each_event_file();
280 mutex_unlock(&event_mutex);
281 }
282
283 static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
284 int enable, int soft_disable)
285 {
286 struct ftrace_event_call *call = file->event_call;
287 int ret = 0;
288 int disable;
289
290 switch (enable) {
291 case 0:
292 /*
293 * When soft_disable is set and enable is cleared, the sm_ref
294 * reference counter is decremented. If it reaches 0, we want
295 * to clear the SOFT_DISABLED flag but leave the event in the
296 * state that it was. That is, if the event was enabled and
297 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
298 * is set we do not want the event to be enabled before we
299 * clear the bit.
300 *
301 * When soft_disable is not set but the SOFT_MODE flag is,
302 * we do nothing. Do not disable the tracepoint, otherwise
303 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
304 */
305 if (soft_disable) {
306 if (atomic_dec_return(&file->sm_ref) > 0)
307 break;
308 disable = file->flags & FTRACE_EVENT_FL_SOFT_DISABLED;
309 clear_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
310 } else
311 disable = !(file->flags & FTRACE_EVENT_FL_SOFT_MODE);
312
313 if (disable && (file->flags & FTRACE_EVENT_FL_ENABLED)) {
314 clear_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
315 if (file->flags & FTRACE_EVENT_FL_RECORDED_CMD) {
316 tracing_stop_cmdline_record();
317 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
318 }
319 call->class->reg(call, TRACE_REG_UNREGISTER, file);
320 }
321 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
322 if (file->flags & FTRACE_EVENT_FL_SOFT_MODE)
323 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
324 else
325 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
326 break;
327 case 1:
328 /*
329 * When soft_disable is set and enable is set, we want to
330 * register the tracepoint for the event, but leave the event
331 * as is. That means, if the event was already enabled, we do
332 * nothing (but set SOFT_MODE). If the event is disabled, we
333 * set SOFT_DISABLED before enabling the event tracepoint, so
334 * it still seems to be disabled.
335 */
336 if (!soft_disable)
337 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
338 else {
339 if (atomic_inc_return(&file->sm_ref) > 1)
340 break;
341 set_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
342 }
343
344 if (!(file->flags & FTRACE_EVENT_FL_ENABLED)) {
345
346 /* Keep the event disabled, when going to SOFT_MODE. */
347 if (soft_disable)
348 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
349
350 if (trace_flags & TRACE_ITER_RECORD_CMD) {
351 tracing_start_cmdline_record();
352 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
353 }
354 ret = call->class->reg(call, TRACE_REG_REGISTER, file);
355 if (ret) {
356 tracing_stop_cmdline_record();
357 pr_info("event trace: Could not enable event "
358 "%s\n", ftrace_event_name(call));
359 break;
360 }
361 set_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
362
363 /* WAS_ENABLED gets set but never cleared. */
364 call->flags |= TRACE_EVENT_FL_WAS_ENABLED;
365 }
366 break;
367 }
368
369 return ret;
370 }
371
372 int trace_event_enable_disable(struct ftrace_event_file *file,
373 int enable, int soft_disable)
374 {
375 return __ftrace_event_enable_disable(file, enable, soft_disable);
376 }
377
378 static int ftrace_event_enable_disable(struct ftrace_event_file *file,
379 int enable)
380 {
381 return __ftrace_event_enable_disable(file, enable, 0);
382 }
383
384 static void ftrace_clear_events(struct trace_array *tr)
385 {
386 struct ftrace_event_file *file;
387
388 mutex_lock(&event_mutex);
389 list_for_each_entry(file, &tr->events, list) {
390 ftrace_event_enable_disable(file, 0);
391 }
392 mutex_unlock(&event_mutex);
393 }
394
395 static void __put_system(struct event_subsystem *system)
396 {
397 struct event_filter *filter = system->filter;
398
399 WARN_ON_ONCE(system_refcount(system) == 0);
400 if (system_refcount_dec(system))
401 return;
402
403 list_del(&system->list);
404
405 if (filter) {
406 kfree(filter->filter_string);
407 kfree(filter);
408 }
409 if (system->ref_count & SYSTEM_FL_FREE_NAME)
410 kfree(system->name);
411 kfree(system);
412 }
413
414 static void __get_system(struct event_subsystem *system)
415 {
416 WARN_ON_ONCE(system_refcount(system) == 0);
417 system_refcount_inc(system);
418 }
419
420 static void __get_system_dir(struct ftrace_subsystem_dir *dir)
421 {
422 WARN_ON_ONCE(dir->ref_count == 0);
423 dir->ref_count++;
424 __get_system(dir->subsystem);
425 }
426
427 static void __put_system_dir(struct ftrace_subsystem_dir *dir)
428 {
429 WARN_ON_ONCE(dir->ref_count == 0);
430 /* If the subsystem is about to be freed, the dir must be too */
431 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
432
433 __put_system(dir->subsystem);
434 if (!--dir->ref_count)
435 kfree(dir);
436 }
437
438 static void put_system(struct ftrace_subsystem_dir *dir)
439 {
440 mutex_lock(&event_mutex);
441 __put_system_dir(dir);
442 mutex_unlock(&event_mutex);
443 }
444
445 static void remove_subsystem(struct ftrace_subsystem_dir *dir)
446 {
447 if (!dir)
448 return;
449
450 if (!--dir->nr_events) {
451 debugfs_remove_recursive(dir->entry);
452 list_del(&dir->list);
453 __put_system_dir(dir);
454 }
455 }
456
457 static void remove_event_file_dir(struct ftrace_event_file *file)
458 {
459 struct dentry *dir = file->dir;
460 struct dentry *child;
461
462 if (dir) {
463 spin_lock(&dir->d_lock); /* probably unneeded */
464 list_for_each_entry(child, &dir->d_subdirs, d_child) {
465 if (child->d_inode) /* probably unneeded */
466 child->d_inode->i_private = NULL;
467 }
468 spin_unlock(&dir->d_lock);
469
470 debugfs_remove_recursive(dir);
471 }
472
473 list_del(&file->list);
474 remove_subsystem(file->system);
475 free_event_filter(file->filter);
476 kmem_cache_free(file_cachep, file);
477 }
478
479 /*
480 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
481 */
482 static int
483 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
484 const char *sub, const char *event, int set)
485 {
486 struct ftrace_event_file *file;
487 struct ftrace_event_call *call;
488 const char *name;
489 int ret = -EINVAL;
490
491 list_for_each_entry(file, &tr->events, list) {
492
493 call = file->event_call;
494 name = ftrace_event_name(call);
495
496 if (!name || !call->class || !call->class->reg)
497 continue;
498
499 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
500 continue;
501
502 if (match &&
503 strcmp(match, name) != 0 &&
504 strcmp(match, call->class->system) != 0)
505 continue;
506
507 if (sub && strcmp(sub, call->class->system) != 0)
508 continue;
509
510 if (event && strcmp(event, name) != 0)
511 continue;
512
513 ftrace_event_enable_disable(file, set);
514
515 ret = 0;
516 }
517
518 return ret;
519 }
520
521 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
522 const char *sub, const char *event, int set)
523 {
524 int ret;
525
526 mutex_lock(&event_mutex);
527 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
528 mutex_unlock(&event_mutex);
529
530 return ret;
531 }
532
533 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
534 {
535 char *event = NULL, *sub = NULL, *match;
536
537 /*
538 * The buf format can be <subsystem>:<event-name>
539 * *:<event-name> means any event by that name.
540 * :<event-name> is the same.
541 *
542 * <subsystem>:* means all events in that subsystem
543 * <subsystem>: means the same.
544 *
545 * <name> (no ':') means all events in a subsystem with
546 * the name <name> or any event that matches <name>
547 */
548
549 match = strsep(&buf, ":");
550 if (buf) {
551 sub = match;
552 event = buf;
553 match = NULL;
554
555 if (!strlen(sub) || strcmp(sub, "*") == 0)
556 sub = NULL;
557 if (!strlen(event) || strcmp(event, "*") == 0)
558 event = NULL;
559 }
560
561 return __ftrace_set_clr_event(tr, match, sub, event, set);
562 }
563
564 /**
565 * trace_set_clr_event - enable or disable an event
566 * @system: system name to match (NULL for any system)
567 * @event: event name to match (NULL for all events, within system)
568 * @set: 1 to enable, 0 to disable
569 *
570 * This is a way for other parts of the kernel to enable or disable
571 * event recording.
572 *
573 * Returns 0 on success, -EINVAL if the parameters do not match any
574 * registered events.
575 */
576 int trace_set_clr_event(const char *system, const char *event, int set)
577 {
578 struct trace_array *tr = top_trace_array();
579
580 if (!tr)
581 return -ENODEV;
582
583 return __ftrace_set_clr_event(tr, NULL, system, event, set);
584 }
585 EXPORT_SYMBOL_GPL(trace_set_clr_event);
586
587 /* 128 should be much more than enough */
588 #define EVENT_BUF_SIZE 127
589
590 static ssize_t
591 ftrace_event_write(struct file *file, const char __user *ubuf,
592 size_t cnt, loff_t *ppos)
593 {
594 struct trace_parser parser;
595 struct seq_file *m = file->private_data;
596 struct trace_array *tr = m->private;
597 ssize_t read, ret;
598
599 if (!cnt)
600 return 0;
601
602 ret = tracing_update_buffers();
603 if (ret < 0)
604 return ret;
605
606 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
607 return -ENOMEM;
608
609 read = trace_get_user(&parser, ubuf, cnt, ppos);
610
611 if (read >= 0 && trace_parser_loaded((&parser))) {
612 int set = 1;
613
614 if (*parser.buffer == '!')
615 set = 0;
616
617 parser.buffer[parser.idx] = 0;
618
619 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
620 if (ret)
621 goto out_put;
622 }
623
624 ret = read;
625
626 out_put:
627 trace_parser_put(&parser);
628
629 return ret;
630 }
631
632 static void *
633 t_next(struct seq_file *m, void *v, loff_t *pos)
634 {
635 struct ftrace_event_file *file = v;
636 struct ftrace_event_call *call;
637 struct trace_array *tr = m->private;
638
639 (*pos)++;
640
641 list_for_each_entry_continue(file, &tr->events, list) {
642 call = file->event_call;
643 /*
644 * The ftrace subsystem is for showing formats only.
645 * They can not be enabled or disabled via the event files.
646 */
647 if (call->class && call->class->reg)
648 return file;
649 }
650
651 return NULL;
652 }
653
654 static void *t_start(struct seq_file *m, loff_t *pos)
655 {
656 struct ftrace_event_file *file;
657 struct trace_array *tr = m->private;
658 loff_t l;
659
660 mutex_lock(&event_mutex);
661
662 file = list_entry(&tr->events, struct ftrace_event_file, list);
663 for (l = 0; l <= *pos; ) {
664 file = t_next(m, file, &l);
665 if (!file)
666 break;
667 }
668 return file;
669 }
670
671 static void *
672 s_next(struct seq_file *m, void *v, loff_t *pos)
673 {
674 struct ftrace_event_file *file = v;
675 struct trace_array *tr = m->private;
676
677 (*pos)++;
678
679 list_for_each_entry_continue(file, &tr->events, list) {
680 if (file->flags & FTRACE_EVENT_FL_ENABLED)
681 return file;
682 }
683
684 return NULL;
685 }
686
687 static void *s_start(struct seq_file *m, loff_t *pos)
688 {
689 struct ftrace_event_file *file;
690 struct trace_array *tr = m->private;
691 loff_t l;
692
693 mutex_lock(&event_mutex);
694
695 file = list_entry(&tr->events, struct ftrace_event_file, list);
696 for (l = 0; l <= *pos; ) {
697 file = s_next(m, file, &l);
698 if (!file)
699 break;
700 }
701 return file;
702 }
703
704 static int t_show(struct seq_file *m, void *v)
705 {
706 struct ftrace_event_file *file = v;
707 struct ftrace_event_call *call = file->event_call;
708
709 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
710 seq_printf(m, "%s:", call->class->system);
711 seq_printf(m, "%s\n", ftrace_event_name(call));
712
713 return 0;
714 }
715
716 static void t_stop(struct seq_file *m, void *p)
717 {
718 mutex_unlock(&event_mutex);
719 }
720
721 static ssize_t
722 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
723 loff_t *ppos)
724 {
725 struct ftrace_event_file *file;
726 unsigned long flags;
727 char buf[4] = "0";
728
729 mutex_lock(&event_mutex);
730 file = event_file_data(filp);
731 if (likely(file))
732 flags = file->flags;
733 mutex_unlock(&event_mutex);
734
735 if (!file)
736 return -ENODEV;
737
738 if (flags & FTRACE_EVENT_FL_ENABLED &&
739 !(flags & FTRACE_EVENT_FL_SOFT_DISABLED))
740 strcpy(buf, "1");
741
742 if (flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
743 flags & FTRACE_EVENT_FL_SOFT_MODE)
744 strcat(buf, "*");
745
746 strcat(buf, "\n");
747
748 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
749 }
750
751 static ssize_t
752 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
753 loff_t *ppos)
754 {
755 struct ftrace_event_file *file;
756 unsigned long val;
757 int ret;
758
759 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
760 if (ret)
761 return ret;
762
763 ret = tracing_update_buffers();
764 if (ret < 0)
765 return ret;
766
767 switch (val) {
768 case 0:
769 case 1:
770 ret = -ENODEV;
771 mutex_lock(&event_mutex);
772 file = event_file_data(filp);
773 if (likely(file))
774 ret = ftrace_event_enable_disable(file, val);
775 mutex_unlock(&event_mutex);
776 break;
777
778 default:
779 return -EINVAL;
780 }
781
782 *ppos += cnt;
783
784 return ret ? ret : cnt;
785 }
786
787 static ssize_t
788 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
789 loff_t *ppos)
790 {
791 const char set_to_char[4] = { '?', '0', '1', 'X' };
792 struct ftrace_subsystem_dir *dir = filp->private_data;
793 struct event_subsystem *system = dir->subsystem;
794 struct ftrace_event_call *call;
795 struct ftrace_event_file *file;
796 struct trace_array *tr = dir->tr;
797 char buf[2];
798 int set = 0;
799 int ret;
800
801 mutex_lock(&event_mutex);
802 list_for_each_entry(file, &tr->events, list) {
803 call = file->event_call;
804 if (!ftrace_event_name(call) || !call->class || !call->class->reg)
805 continue;
806
807 if (system && strcmp(call->class->system, system->name) != 0)
808 continue;
809
810 /*
811 * We need to find out if all the events are set
812 * or if all events or cleared, or if we have
813 * a mixture.
814 */
815 set |= (1 << !!(file->flags & FTRACE_EVENT_FL_ENABLED));
816
817 /*
818 * If we have a mixture, no need to look further.
819 */
820 if (set == 3)
821 break;
822 }
823 mutex_unlock(&event_mutex);
824
825 buf[0] = set_to_char[set];
826 buf[1] = '\n';
827
828 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
829
830 return ret;
831 }
832
833 static ssize_t
834 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
835 loff_t *ppos)
836 {
837 struct ftrace_subsystem_dir *dir = filp->private_data;
838 struct event_subsystem *system = dir->subsystem;
839 const char *name = NULL;
840 unsigned long val;
841 ssize_t ret;
842
843 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
844 if (ret)
845 return ret;
846
847 ret = tracing_update_buffers();
848 if (ret < 0)
849 return ret;
850
851 if (val != 0 && val != 1)
852 return -EINVAL;
853
854 /*
855 * Opening of "enable" adds a ref count to system,
856 * so the name is safe to use.
857 */
858 if (system)
859 name = system->name;
860
861 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
862 if (ret)
863 goto out;
864
865 ret = cnt;
866
867 out:
868 *ppos += cnt;
869
870 return ret;
871 }
872
873 enum {
874 FORMAT_HEADER = 1,
875 FORMAT_FIELD_SEPERATOR = 2,
876 FORMAT_PRINTFMT = 3,
877 };
878
879 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
880 {
881 struct ftrace_event_call *call = event_file_data(m->private);
882 struct list_head *common_head = &ftrace_common_fields;
883 struct list_head *head = trace_get_fields(call);
884 struct list_head *node = v;
885
886 (*pos)++;
887
888 switch ((unsigned long)v) {
889 case FORMAT_HEADER:
890 node = common_head;
891 break;
892
893 case FORMAT_FIELD_SEPERATOR:
894 node = head;
895 break;
896
897 case FORMAT_PRINTFMT:
898 /* all done */
899 return NULL;
900 }
901
902 node = node->prev;
903 if (node == common_head)
904 return (void *)FORMAT_FIELD_SEPERATOR;
905 else if (node == head)
906 return (void *)FORMAT_PRINTFMT;
907 else
908 return node;
909 }
910
911 static int f_show(struct seq_file *m, void *v)
912 {
913 struct ftrace_event_call *call = event_file_data(m->private);
914 struct ftrace_event_field *field;
915 const char *array_descriptor;
916
917 switch ((unsigned long)v) {
918 case FORMAT_HEADER:
919 seq_printf(m, "name: %s\n", ftrace_event_name(call));
920 seq_printf(m, "ID: %d\n", call->event.type);
921 seq_puts(m, "format:\n");
922 return 0;
923
924 case FORMAT_FIELD_SEPERATOR:
925 seq_putc(m, '\n');
926 return 0;
927
928 case FORMAT_PRINTFMT:
929 seq_printf(m, "\nprint fmt: %s\n",
930 call->print_fmt);
931 return 0;
932 }
933
934 field = list_entry(v, struct ftrace_event_field, link);
935 /*
936 * Smartly shows the array type(except dynamic array).
937 * Normal:
938 * field:TYPE VAR
939 * If TYPE := TYPE[LEN], it is shown:
940 * field:TYPE VAR[LEN]
941 */
942 array_descriptor = strchr(field->type, '[');
943
944 if (!strncmp(field->type, "__data_loc", 10))
945 array_descriptor = NULL;
946
947 if (!array_descriptor)
948 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
949 field->type, field->name, field->offset,
950 field->size, !!field->is_signed);
951 else
952 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
953 (int)(array_descriptor - field->type),
954 field->type, field->name,
955 array_descriptor, field->offset,
956 field->size, !!field->is_signed);
957
958 return 0;
959 }
960
961 static void *f_start(struct seq_file *m, loff_t *pos)
962 {
963 void *p = (void *)FORMAT_HEADER;
964 loff_t l = 0;
965
966 /* ->stop() is called even if ->start() fails */
967 mutex_lock(&event_mutex);
968 if (!event_file_data(m->private))
969 return ERR_PTR(-ENODEV);
970
971 while (l < *pos && p)
972 p = f_next(m, p, &l);
973
974 return p;
975 }
976
977 static void f_stop(struct seq_file *m, void *p)
978 {
979 mutex_unlock(&event_mutex);
980 }
981
982 static const struct seq_operations trace_format_seq_ops = {
983 .start = f_start,
984 .next = f_next,
985 .stop = f_stop,
986 .show = f_show,
987 };
988
989 static int trace_format_open(struct inode *inode, struct file *file)
990 {
991 struct seq_file *m;
992 int ret;
993
994 ret = seq_open(file, &trace_format_seq_ops);
995 if (ret < 0)
996 return ret;
997
998 m = file->private_data;
999 m->private = file;
1000
1001 return 0;
1002 }
1003
1004 static ssize_t
1005 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1006 {
1007 int id = (long)event_file_data(filp);
1008 char buf[32];
1009 int len;
1010
1011 if (*ppos)
1012 return 0;
1013
1014 if (unlikely(!id))
1015 return -ENODEV;
1016
1017 len = sprintf(buf, "%d\n", id);
1018
1019 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1020 }
1021
1022 static ssize_t
1023 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1024 loff_t *ppos)
1025 {
1026 struct ftrace_event_file *file;
1027 struct trace_seq *s;
1028 int r = -ENODEV;
1029
1030 if (*ppos)
1031 return 0;
1032
1033 s = kmalloc(sizeof(*s), GFP_KERNEL);
1034
1035 if (!s)
1036 return -ENOMEM;
1037
1038 trace_seq_init(s);
1039
1040 mutex_lock(&event_mutex);
1041 file = event_file_data(filp);
1042 if (file)
1043 print_event_filter(file, s);
1044 mutex_unlock(&event_mutex);
1045
1046 if (file)
1047 r = simple_read_from_buffer(ubuf, cnt, ppos,
1048 s->buffer, trace_seq_used(s));
1049
1050 kfree(s);
1051
1052 return r;
1053 }
1054
1055 static ssize_t
1056 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1057 loff_t *ppos)
1058 {
1059 struct ftrace_event_file *file;
1060 char *buf;
1061 int err = -ENODEV;
1062
1063 if (cnt >= PAGE_SIZE)
1064 return -EINVAL;
1065
1066 buf = (char *)__get_free_page(GFP_TEMPORARY);
1067 if (!buf)
1068 return -ENOMEM;
1069
1070 if (copy_from_user(buf, ubuf, cnt)) {
1071 free_page((unsigned long) buf);
1072 return -EFAULT;
1073 }
1074 buf[cnt] = '\0';
1075
1076 mutex_lock(&event_mutex);
1077 file = event_file_data(filp);
1078 if (file)
1079 err = apply_event_filter(file, buf);
1080 mutex_unlock(&event_mutex);
1081
1082 free_page((unsigned long) buf);
1083 if (err < 0)
1084 return err;
1085
1086 *ppos += cnt;
1087
1088 return cnt;
1089 }
1090
1091 static LIST_HEAD(event_subsystems);
1092
1093 static int subsystem_open(struct inode *inode, struct file *filp)
1094 {
1095 struct event_subsystem *system = NULL;
1096 struct ftrace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1097 struct trace_array *tr;
1098 int ret;
1099
1100 if (tracing_is_disabled())
1101 return -ENODEV;
1102
1103 /* Make sure the system still exists */
1104 mutex_lock(&trace_types_lock);
1105 mutex_lock(&event_mutex);
1106 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1107 list_for_each_entry(dir, &tr->systems, list) {
1108 if (dir == inode->i_private) {
1109 /* Don't open systems with no events */
1110 if (dir->nr_events) {
1111 __get_system_dir(dir);
1112 system = dir->subsystem;
1113 }
1114 goto exit_loop;
1115 }
1116 }
1117 }
1118 exit_loop:
1119 mutex_unlock(&event_mutex);
1120 mutex_unlock(&trace_types_lock);
1121
1122 if (!system)
1123 return -ENODEV;
1124
1125 /* Some versions of gcc think dir can be uninitialized here */
1126 WARN_ON(!dir);
1127
1128 /* Still need to increment the ref count of the system */
1129 if (trace_array_get(tr) < 0) {
1130 put_system(dir);
1131 return -ENODEV;
1132 }
1133
1134 ret = tracing_open_generic(inode, filp);
1135 if (ret < 0) {
1136 trace_array_put(tr);
1137 put_system(dir);
1138 }
1139
1140 return ret;
1141 }
1142
1143 static int system_tr_open(struct inode *inode, struct file *filp)
1144 {
1145 struct ftrace_subsystem_dir *dir;
1146 struct trace_array *tr = inode->i_private;
1147 int ret;
1148
1149 if (tracing_is_disabled())
1150 return -ENODEV;
1151
1152 if (trace_array_get(tr) < 0)
1153 return -ENODEV;
1154
1155 /* Make a temporary dir that has no system but points to tr */
1156 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1157 if (!dir) {
1158 trace_array_put(tr);
1159 return -ENOMEM;
1160 }
1161
1162 dir->tr = tr;
1163
1164 ret = tracing_open_generic(inode, filp);
1165 if (ret < 0) {
1166 trace_array_put(tr);
1167 kfree(dir);
1168 return ret;
1169 }
1170
1171 filp->private_data = dir;
1172
1173 return 0;
1174 }
1175
1176 static int subsystem_release(struct inode *inode, struct file *file)
1177 {
1178 struct ftrace_subsystem_dir *dir = file->private_data;
1179
1180 trace_array_put(dir->tr);
1181
1182 /*
1183 * If dir->subsystem is NULL, then this is a temporary
1184 * descriptor that was made for a trace_array to enable
1185 * all subsystems.
1186 */
1187 if (dir->subsystem)
1188 put_system(dir);
1189 else
1190 kfree(dir);
1191
1192 return 0;
1193 }
1194
1195 static ssize_t
1196 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1197 loff_t *ppos)
1198 {
1199 struct ftrace_subsystem_dir *dir = filp->private_data;
1200 struct event_subsystem *system = dir->subsystem;
1201 struct trace_seq *s;
1202 int r;
1203
1204 if (*ppos)
1205 return 0;
1206
1207 s = kmalloc(sizeof(*s), GFP_KERNEL);
1208 if (!s)
1209 return -ENOMEM;
1210
1211 trace_seq_init(s);
1212
1213 print_subsystem_event_filter(system, s);
1214 r = simple_read_from_buffer(ubuf, cnt, ppos,
1215 s->buffer, trace_seq_used(s));
1216
1217 kfree(s);
1218
1219 return r;
1220 }
1221
1222 static ssize_t
1223 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1224 loff_t *ppos)
1225 {
1226 struct ftrace_subsystem_dir *dir = filp->private_data;
1227 char *buf;
1228 int err;
1229
1230 if (cnt >= PAGE_SIZE)
1231 return -EINVAL;
1232
1233 buf = (char *)__get_free_page(GFP_TEMPORARY);
1234 if (!buf)
1235 return -ENOMEM;
1236
1237 if (copy_from_user(buf, ubuf, cnt)) {
1238 free_page((unsigned long) buf);
1239 return -EFAULT;
1240 }
1241 buf[cnt] = '\0';
1242
1243 err = apply_subsystem_event_filter(dir, buf);
1244 free_page((unsigned long) buf);
1245 if (err < 0)
1246 return err;
1247
1248 *ppos += cnt;
1249
1250 return cnt;
1251 }
1252
1253 static ssize_t
1254 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1255 {
1256 int (*func)(struct trace_seq *s) = filp->private_data;
1257 struct trace_seq *s;
1258 int r;
1259
1260 if (*ppos)
1261 return 0;
1262
1263 s = kmalloc(sizeof(*s), GFP_KERNEL);
1264 if (!s)
1265 return -ENOMEM;
1266
1267 trace_seq_init(s);
1268
1269 func(s);
1270 r = simple_read_from_buffer(ubuf, cnt, ppos,
1271 s->buffer, trace_seq_used(s));
1272
1273 kfree(s);
1274
1275 return r;
1276 }
1277
1278 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1279 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1280 static int ftrace_event_release(struct inode *inode, struct file *file);
1281
1282 static const struct seq_operations show_event_seq_ops = {
1283 .start = t_start,
1284 .next = t_next,
1285 .show = t_show,
1286 .stop = t_stop,
1287 };
1288
1289 static const struct seq_operations show_set_event_seq_ops = {
1290 .start = s_start,
1291 .next = s_next,
1292 .show = t_show,
1293 .stop = t_stop,
1294 };
1295
1296 static const struct file_operations ftrace_avail_fops = {
1297 .open = ftrace_event_avail_open,
1298 .read = seq_read,
1299 .llseek = seq_lseek,
1300 .release = seq_release,
1301 };
1302
1303 static const struct file_operations ftrace_set_event_fops = {
1304 .open = ftrace_event_set_open,
1305 .read = seq_read,
1306 .write = ftrace_event_write,
1307 .llseek = seq_lseek,
1308 .release = ftrace_event_release,
1309 };
1310
1311 static const struct file_operations ftrace_enable_fops = {
1312 .open = tracing_open_generic,
1313 .read = event_enable_read,
1314 .write = event_enable_write,
1315 .llseek = default_llseek,
1316 };
1317
1318 static const struct file_operations ftrace_event_format_fops = {
1319 .open = trace_format_open,
1320 .read = seq_read,
1321 .llseek = seq_lseek,
1322 .release = seq_release,
1323 };
1324
1325 static const struct file_operations ftrace_event_id_fops = {
1326 .read = event_id_read,
1327 .llseek = default_llseek,
1328 };
1329
1330 static const struct file_operations ftrace_event_filter_fops = {
1331 .open = tracing_open_generic,
1332 .read = event_filter_read,
1333 .write = event_filter_write,
1334 .llseek = default_llseek,
1335 };
1336
1337 static const struct file_operations ftrace_subsystem_filter_fops = {
1338 .open = subsystem_open,
1339 .read = subsystem_filter_read,
1340 .write = subsystem_filter_write,
1341 .llseek = default_llseek,
1342 .release = subsystem_release,
1343 };
1344
1345 static const struct file_operations ftrace_system_enable_fops = {
1346 .open = subsystem_open,
1347 .read = system_enable_read,
1348 .write = system_enable_write,
1349 .llseek = default_llseek,
1350 .release = subsystem_release,
1351 };
1352
1353 static const struct file_operations ftrace_tr_enable_fops = {
1354 .open = system_tr_open,
1355 .read = system_enable_read,
1356 .write = system_enable_write,
1357 .llseek = default_llseek,
1358 .release = subsystem_release,
1359 };
1360
1361 static const struct file_operations ftrace_show_header_fops = {
1362 .open = tracing_open_generic,
1363 .read = show_header,
1364 .llseek = default_llseek,
1365 };
1366
1367 static int
1368 ftrace_event_open(struct inode *inode, struct file *file,
1369 const struct seq_operations *seq_ops)
1370 {
1371 struct seq_file *m;
1372 int ret;
1373
1374 ret = seq_open(file, seq_ops);
1375 if (ret < 0)
1376 return ret;
1377 m = file->private_data;
1378 /* copy tr over to seq ops */
1379 m->private = inode->i_private;
1380
1381 return ret;
1382 }
1383
1384 static int ftrace_event_release(struct inode *inode, struct file *file)
1385 {
1386 struct trace_array *tr = inode->i_private;
1387
1388 trace_array_put(tr);
1389
1390 return seq_release(inode, file);
1391 }
1392
1393 static int
1394 ftrace_event_avail_open(struct inode *inode, struct file *file)
1395 {
1396 const struct seq_operations *seq_ops = &show_event_seq_ops;
1397
1398 return ftrace_event_open(inode, file, seq_ops);
1399 }
1400
1401 static int
1402 ftrace_event_set_open(struct inode *inode, struct file *file)
1403 {
1404 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1405 struct trace_array *tr = inode->i_private;
1406 int ret;
1407
1408 if (trace_array_get(tr) < 0)
1409 return -ENODEV;
1410
1411 if ((file->f_mode & FMODE_WRITE) &&
1412 (file->f_flags & O_TRUNC))
1413 ftrace_clear_events(tr);
1414
1415 ret = ftrace_event_open(inode, file, seq_ops);
1416 if (ret < 0)
1417 trace_array_put(tr);
1418 return ret;
1419 }
1420
1421 static struct event_subsystem *
1422 create_new_subsystem(const char *name)
1423 {
1424 struct event_subsystem *system;
1425
1426 /* need to create new entry */
1427 system = kmalloc(sizeof(*system), GFP_KERNEL);
1428 if (!system)
1429 return NULL;
1430
1431 system->ref_count = 1;
1432
1433 /* Only allocate if dynamic (kprobes and modules) */
1434 if (!core_kernel_data((unsigned long)name)) {
1435 system->ref_count |= SYSTEM_FL_FREE_NAME;
1436 system->name = kstrdup(name, GFP_KERNEL);
1437 if (!system->name)
1438 goto out_free;
1439 } else
1440 system->name = name;
1441
1442 system->filter = NULL;
1443
1444 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1445 if (!system->filter)
1446 goto out_free;
1447
1448 list_add(&system->list, &event_subsystems);
1449
1450 return system;
1451
1452 out_free:
1453 if (system->ref_count & SYSTEM_FL_FREE_NAME)
1454 kfree(system->name);
1455 kfree(system);
1456 return NULL;
1457 }
1458
1459 static struct dentry *
1460 event_subsystem_dir(struct trace_array *tr, const char *name,
1461 struct ftrace_event_file *file, struct dentry *parent)
1462 {
1463 struct ftrace_subsystem_dir *dir;
1464 struct event_subsystem *system;
1465 struct dentry *entry;
1466
1467 /* First see if we did not already create this dir */
1468 list_for_each_entry(dir, &tr->systems, list) {
1469 system = dir->subsystem;
1470 if (strcmp(system->name, name) == 0) {
1471 dir->nr_events++;
1472 file->system = dir;
1473 return dir->entry;
1474 }
1475 }
1476
1477 /* Now see if the system itself exists. */
1478 list_for_each_entry(system, &event_subsystems, list) {
1479 if (strcmp(system->name, name) == 0)
1480 break;
1481 }
1482 /* Reset system variable when not found */
1483 if (&system->list == &event_subsystems)
1484 system = NULL;
1485
1486 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1487 if (!dir)
1488 goto out_fail;
1489
1490 if (!system) {
1491 system = create_new_subsystem(name);
1492 if (!system)
1493 goto out_free;
1494 } else
1495 __get_system(system);
1496
1497 dir->entry = debugfs_create_dir(name, parent);
1498 if (!dir->entry) {
1499 pr_warn("Failed to create system directory %s\n", name);
1500 __put_system(system);
1501 goto out_free;
1502 }
1503
1504 dir->tr = tr;
1505 dir->ref_count = 1;
1506 dir->nr_events = 1;
1507 dir->subsystem = system;
1508 file->system = dir;
1509
1510 entry = debugfs_create_file("filter", 0644, dir->entry, dir,
1511 &ftrace_subsystem_filter_fops);
1512 if (!entry) {
1513 kfree(system->filter);
1514 system->filter = NULL;
1515 pr_warn("Could not create debugfs '%s/filter' entry\n", name);
1516 }
1517
1518 trace_create_file("enable", 0644, dir->entry, dir,
1519 &ftrace_system_enable_fops);
1520
1521 list_add(&dir->list, &tr->systems);
1522
1523 return dir->entry;
1524
1525 out_free:
1526 kfree(dir);
1527 out_fail:
1528 /* Only print this message if failed on memory allocation */
1529 if (!dir || !system)
1530 pr_warn("No memory to create event subsystem %s\n", name);
1531 return NULL;
1532 }
1533
1534 static int
1535 event_create_dir(struct dentry *parent, struct ftrace_event_file *file)
1536 {
1537 struct ftrace_event_call *call = file->event_call;
1538 struct trace_array *tr = file->tr;
1539 struct list_head *head;
1540 struct dentry *d_events;
1541 const char *name;
1542 int ret;
1543
1544 /*
1545 * If the trace point header did not define TRACE_SYSTEM
1546 * then the system would be called "TRACE_SYSTEM".
1547 */
1548 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1549 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1550 if (!d_events)
1551 return -ENOMEM;
1552 } else
1553 d_events = parent;
1554
1555 name = ftrace_event_name(call);
1556 file->dir = debugfs_create_dir(name, d_events);
1557 if (!file->dir) {
1558 pr_warn("Could not create debugfs '%s' directory\n", name);
1559 return -1;
1560 }
1561
1562 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1563 trace_create_file("enable", 0644, file->dir, file,
1564 &ftrace_enable_fops);
1565
1566 #ifdef CONFIG_PERF_EVENTS
1567 if (call->event.type && call->class->reg)
1568 trace_create_file("id", 0444, file->dir,
1569 (void *)(long)call->event.type,
1570 &ftrace_event_id_fops);
1571 #endif
1572
1573 /*
1574 * Other events may have the same class. Only update
1575 * the fields if they are not already defined.
1576 */
1577 head = trace_get_fields(call);
1578 if (list_empty(head)) {
1579 ret = call->class->define_fields(call);
1580 if (ret < 0) {
1581 pr_warn("Could not initialize trace point events/%s\n",
1582 name);
1583 return -1;
1584 }
1585 }
1586 trace_create_file("filter", 0644, file->dir, file,
1587 &ftrace_event_filter_fops);
1588
1589 trace_create_file("trigger", 0644, file->dir, file,
1590 &event_trigger_fops);
1591
1592 trace_create_file("format", 0444, file->dir, call,
1593 &ftrace_event_format_fops);
1594
1595 return 0;
1596 }
1597
1598 static void remove_event_from_tracers(struct ftrace_event_call *call)
1599 {
1600 struct ftrace_event_file *file;
1601 struct trace_array *tr;
1602
1603 do_for_each_event_file_safe(tr, file) {
1604 if (file->event_call != call)
1605 continue;
1606
1607 remove_event_file_dir(file);
1608 /*
1609 * The do_for_each_event_file_safe() is
1610 * a double loop. After finding the call for this
1611 * trace_array, we use break to jump to the next
1612 * trace_array.
1613 */
1614 break;
1615 } while_for_each_event_file();
1616 }
1617
1618 static void event_remove(struct ftrace_event_call *call)
1619 {
1620 struct trace_array *tr;
1621 struct ftrace_event_file *file;
1622
1623 do_for_each_event_file(tr, file) {
1624 if (file->event_call != call)
1625 continue;
1626 ftrace_event_enable_disable(file, 0);
1627 /*
1628 * The do_for_each_event_file() is
1629 * a double loop. After finding the call for this
1630 * trace_array, we use break to jump to the next
1631 * trace_array.
1632 */
1633 break;
1634 } while_for_each_event_file();
1635
1636 if (call->event.funcs)
1637 __unregister_ftrace_event(&call->event);
1638 remove_event_from_tracers(call);
1639 list_del(&call->list);
1640 }
1641
1642 static int event_init(struct ftrace_event_call *call)
1643 {
1644 int ret = 0;
1645 const char *name;
1646
1647 name = ftrace_event_name(call);
1648 if (WARN_ON(!name))
1649 return -EINVAL;
1650
1651 if (call->class->raw_init) {
1652 ret = call->class->raw_init(call);
1653 if (ret < 0 && ret != -ENOSYS)
1654 pr_warn("Could not initialize trace events/%s\n", name);
1655 }
1656
1657 return ret;
1658 }
1659
1660 static int
1661 __register_event(struct ftrace_event_call *call, struct module *mod)
1662 {
1663 int ret;
1664
1665 ret = event_init(call);
1666 if (ret < 0)
1667 return ret;
1668
1669 list_add(&call->list, &ftrace_events);
1670 call->mod = mod;
1671
1672 return 0;
1673 }
1674
1675 static struct ftrace_event_file *
1676 trace_create_new_event(struct ftrace_event_call *call,
1677 struct trace_array *tr)
1678 {
1679 struct ftrace_event_file *file;
1680
1681 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
1682 if (!file)
1683 return NULL;
1684
1685 file->event_call = call;
1686 file->tr = tr;
1687 atomic_set(&file->sm_ref, 0);
1688 atomic_set(&file->tm_ref, 0);
1689 INIT_LIST_HEAD(&file->triggers);
1690 list_add(&file->list, &tr->events);
1691
1692 return file;
1693 }
1694
1695 /* Add an event to a trace directory */
1696 static int
1697 __trace_add_new_event(struct ftrace_event_call *call, struct trace_array *tr)
1698 {
1699 struct ftrace_event_file *file;
1700
1701 file = trace_create_new_event(call, tr);
1702 if (!file)
1703 return -ENOMEM;
1704
1705 return event_create_dir(tr->event_dir, file);
1706 }
1707
1708 /*
1709 * Just create a decriptor for early init. A descriptor is required
1710 * for enabling events at boot. We want to enable events before
1711 * the filesystem is initialized.
1712 */
1713 static __init int
1714 __trace_early_add_new_event(struct ftrace_event_call *call,
1715 struct trace_array *tr)
1716 {
1717 struct ftrace_event_file *file;
1718
1719 file = trace_create_new_event(call, tr);
1720 if (!file)
1721 return -ENOMEM;
1722
1723 return 0;
1724 }
1725
1726 struct ftrace_module_file_ops;
1727 static void __add_event_to_tracers(struct ftrace_event_call *call);
1728
1729 /* Add an additional event_call dynamically */
1730 int trace_add_event_call(struct ftrace_event_call *call)
1731 {
1732 int ret;
1733 mutex_lock(&trace_types_lock);
1734 mutex_lock(&event_mutex);
1735
1736 ret = __register_event(call, NULL);
1737 if (ret >= 0)
1738 __add_event_to_tracers(call);
1739
1740 mutex_unlock(&event_mutex);
1741 mutex_unlock(&trace_types_lock);
1742 return ret;
1743 }
1744
1745 /*
1746 * Must be called under locking of trace_types_lock, event_mutex and
1747 * trace_event_sem.
1748 */
1749 static void __trace_remove_event_call(struct ftrace_event_call *call)
1750 {
1751 event_remove(call);
1752 trace_destroy_fields(call);
1753 free_event_filter(call->filter);
1754 call->filter = NULL;
1755 }
1756
1757 static int probe_remove_event_call(struct ftrace_event_call *call)
1758 {
1759 struct trace_array *tr;
1760 struct ftrace_event_file *file;
1761
1762 #ifdef CONFIG_PERF_EVENTS
1763 if (call->perf_refcount)
1764 return -EBUSY;
1765 #endif
1766 do_for_each_event_file(tr, file) {
1767 if (file->event_call != call)
1768 continue;
1769 /*
1770 * We can't rely on ftrace_event_enable_disable(enable => 0)
1771 * we are going to do, FTRACE_EVENT_FL_SOFT_MODE can suppress
1772 * TRACE_REG_UNREGISTER.
1773 */
1774 if (file->flags & FTRACE_EVENT_FL_ENABLED)
1775 return -EBUSY;
1776 /*
1777 * The do_for_each_event_file_safe() is
1778 * a double loop. After finding the call for this
1779 * trace_array, we use break to jump to the next
1780 * trace_array.
1781 */
1782 break;
1783 } while_for_each_event_file();
1784
1785 __trace_remove_event_call(call);
1786
1787 return 0;
1788 }
1789
1790 /* Remove an event_call */
1791 int trace_remove_event_call(struct ftrace_event_call *call)
1792 {
1793 int ret;
1794
1795 mutex_lock(&trace_types_lock);
1796 mutex_lock(&event_mutex);
1797 down_write(&trace_event_sem);
1798 ret = probe_remove_event_call(call);
1799 up_write(&trace_event_sem);
1800 mutex_unlock(&event_mutex);
1801 mutex_unlock(&trace_types_lock);
1802
1803 return ret;
1804 }
1805
1806 #define for_each_event(event, start, end) \
1807 for (event = start; \
1808 (unsigned long)event < (unsigned long)end; \
1809 event++)
1810
1811 #ifdef CONFIG_MODULES
1812
1813 static void trace_module_add_events(struct module *mod)
1814 {
1815 struct ftrace_event_call **call, **start, **end;
1816
1817 if (!mod->num_trace_events)
1818 return;
1819
1820 /* Don't add infrastructure for mods without tracepoints */
1821 if (trace_module_has_bad_taint(mod)) {
1822 pr_err("%s: module has bad taint, not creating trace events\n",
1823 mod->name);
1824 return;
1825 }
1826
1827 start = mod->trace_events;
1828 end = mod->trace_events + mod->num_trace_events;
1829
1830 for_each_event(call, start, end) {
1831 __register_event(*call, mod);
1832 __add_event_to_tracers(*call);
1833 }
1834 }
1835
1836 static void trace_module_remove_events(struct module *mod)
1837 {
1838 struct ftrace_event_call *call, *p;
1839 bool clear_trace = false;
1840
1841 down_write(&trace_event_sem);
1842 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1843 if (call->mod == mod) {
1844 if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
1845 clear_trace = true;
1846 __trace_remove_event_call(call);
1847 }
1848 }
1849 up_write(&trace_event_sem);
1850
1851 /*
1852 * It is safest to reset the ring buffer if the module being unloaded
1853 * registered any events that were used. The only worry is if
1854 * a new module gets loaded, and takes on the same id as the events
1855 * of this module. When printing out the buffer, traced events left
1856 * over from this module may be passed to the new module events and
1857 * unexpected results may occur.
1858 */
1859 if (clear_trace)
1860 tracing_reset_all_online_cpus();
1861 }
1862
1863 static int trace_module_notify(struct notifier_block *self,
1864 unsigned long val, void *data)
1865 {
1866 struct module *mod = data;
1867
1868 mutex_lock(&trace_types_lock);
1869 mutex_lock(&event_mutex);
1870 switch (val) {
1871 case MODULE_STATE_COMING:
1872 trace_module_add_events(mod);
1873 break;
1874 case MODULE_STATE_GOING:
1875 trace_module_remove_events(mod);
1876 break;
1877 }
1878 mutex_unlock(&event_mutex);
1879 mutex_unlock(&trace_types_lock);
1880
1881 return 0;
1882 }
1883
1884 static struct notifier_block trace_module_nb = {
1885 .notifier_call = trace_module_notify,
1886 .priority = 0,
1887 };
1888 #endif /* CONFIG_MODULES */
1889
1890 /* Create a new event directory structure for a trace directory. */
1891 static void
1892 __trace_add_event_dirs(struct trace_array *tr)
1893 {
1894 struct ftrace_event_call *call;
1895 int ret;
1896
1897 list_for_each_entry(call, &ftrace_events, list) {
1898 ret = __trace_add_new_event(call, tr);
1899 if (ret < 0)
1900 pr_warn("Could not create directory for event %s\n",
1901 ftrace_event_name(call));
1902 }
1903 }
1904
1905 struct ftrace_event_file *
1906 find_event_file(struct trace_array *tr, const char *system, const char *event)
1907 {
1908 struct ftrace_event_file *file;
1909 struct ftrace_event_call *call;
1910 const char *name;
1911
1912 list_for_each_entry(file, &tr->events, list) {
1913
1914 call = file->event_call;
1915 name = ftrace_event_name(call);
1916
1917 if (!name || !call->class || !call->class->reg)
1918 continue;
1919
1920 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1921 continue;
1922
1923 if (strcmp(event, name) == 0 &&
1924 strcmp(system, call->class->system) == 0)
1925 return file;
1926 }
1927 return NULL;
1928 }
1929
1930 #ifdef CONFIG_DYNAMIC_FTRACE
1931
1932 /* Avoid typos */
1933 #define ENABLE_EVENT_STR "enable_event"
1934 #define DISABLE_EVENT_STR "disable_event"
1935
1936 struct event_probe_data {
1937 struct ftrace_event_file *file;
1938 unsigned long count;
1939 int ref;
1940 bool enable;
1941 };
1942
1943 static void
1944 event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1945 {
1946 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1947 struct event_probe_data *data = *pdata;
1948
1949 if (!data)
1950 return;
1951
1952 if (data->enable)
1953 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1954 else
1955 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1956 }
1957
1958 static void
1959 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1960 {
1961 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1962 struct event_probe_data *data = *pdata;
1963
1964 if (!data)
1965 return;
1966
1967 if (!data->count)
1968 return;
1969
1970 /* Skip if the event is in a state we want to switch to */
1971 if (data->enable == !(data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
1972 return;
1973
1974 if (data->count != -1)
1975 (data->count)--;
1976
1977 event_enable_probe(ip, parent_ip, _data);
1978 }
1979
1980 static int
1981 event_enable_print(struct seq_file *m, unsigned long ip,
1982 struct ftrace_probe_ops *ops, void *_data)
1983 {
1984 struct event_probe_data *data = _data;
1985
1986 seq_printf(m, "%ps:", (void *)ip);
1987
1988 seq_printf(m, "%s:%s:%s",
1989 data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
1990 data->file->event_call->class->system,
1991 ftrace_event_name(data->file->event_call));
1992
1993 if (data->count == -1)
1994 seq_puts(m, ":unlimited\n");
1995 else
1996 seq_printf(m, ":count=%ld\n", data->count);
1997
1998 return 0;
1999 }
2000
2001 static int
2002 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
2003 void **_data)
2004 {
2005 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2006 struct event_probe_data *data = *pdata;
2007
2008 data->ref++;
2009 return 0;
2010 }
2011
2012 static void
2013 event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
2014 void **_data)
2015 {
2016 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2017 struct event_probe_data *data = *pdata;
2018
2019 if (WARN_ON_ONCE(data->ref <= 0))
2020 return;
2021
2022 data->ref--;
2023 if (!data->ref) {
2024 /* Remove the SOFT_MODE flag */
2025 __ftrace_event_enable_disable(data->file, 0, 1);
2026 module_put(data->file->event_call->mod);
2027 kfree(data);
2028 }
2029 *pdata = NULL;
2030 }
2031
2032 static struct ftrace_probe_ops event_enable_probe_ops = {
2033 .func = event_enable_probe,
2034 .print = event_enable_print,
2035 .init = event_enable_init,
2036 .free = event_enable_free,
2037 };
2038
2039 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2040 .func = event_enable_count_probe,
2041 .print = event_enable_print,
2042 .init = event_enable_init,
2043 .free = event_enable_free,
2044 };
2045
2046 static struct ftrace_probe_ops event_disable_probe_ops = {
2047 .func = event_enable_probe,
2048 .print = event_enable_print,
2049 .init = event_enable_init,
2050 .free = event_enable_free,
2051 };
2052
2053 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2054 .func = event_enable_count_probe,
2055 .print = event_enable_print,
2056 .init = event_enable_init,
2057 .free = event_enable_free,
2058 };
2059
2060 static int
2061 event_enable_func(struct ftrace_hash *hash,
2062 char *glob, char *cmd, char *param, int enabled)
2063 {
2064 struct trace_array *tr = top_trace_array();
2065 struct ftrace_event_file *file;
2066 struct ftrace_probe_ops *ops;
2067 struct event_probe_data *data;
2068 const char *system;
2069 const char *event;
2070 char *number;
2071 bool enable;
2072 int ret;
2073
2074 if (!tr)
2075 return -ENODEV;
2076
2077 /* hash funcs only work with set_ftrace_filter */
2078 if (!enabled || !param)
2079 return -EINVAL;
2080
2081 system = strsep(&param, ":");
2082 if (!param)
2083 return -EINVAL;
2084
2085 event = strsep(&param, ":");
2086
2087 mutex_lock(&event_mutex);
2088
2089 ret = -EINVAL;
2090 file = find_event_file(tr, system, event);
2091 if (!file)
2092 goto out;
2093
2094 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2095
2096 if (enable)
2097 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2098 else
2099 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2100
2101 if (glob[0] == '!') {
2102 unregister_ftrace_function_probe_func(glob+1, ops);
2103 ret = 0;
2104 goto out;
2105 }
2106
2107 ret = -ENOMEM;
2108 data = kzalloc(sizeof(*data), GFP_KERNEL);
2109 if (!data)
2110 goto out;
2111
2112 data->enable = enable;
2113 data->count = -1;
2114 data->file = file;
2115
2116 if (!param)
2117 goto out_reg;
2118
2119 number = strsep(&param, ":");
2120
2121 ret = -EINVAL;
2122 if (!strlen(number))
2123 goto out_free;
2124
2125 /*
2126 * We use the callback data field (which is a pointer)
2127 * as our counter.
2128 */
2129 ret = kstrtoul(number, 0, &data->count);
2130 if (ret)
2131 goto out_free;
2132
2133 out_reg:
2134 /* Don't let event modules unload while probe registered */
2135 ret = try_module_get(file->event_call->mod);
2136 if (!ret) {
2137 ret = -EBUSY;
2138 goto out_free;
2139 }
2140
2141 ret = __ftrace_event_enable_disable(file, 1, 1);
2142 if (ret < 0)
2143 goto out_put;
2144 ret = register_ftrace_function_probe(glob, ops, data);
2145 /*
2146 * The above returns on success the # of functions enabled,
2147 * but if it didn't find any functions it returns zero.
2148 * Consider no functions a failure too.
2149 */
2150 if (!ret) {
2151 ret = -ENOENT;
2152 goto out_disable;
2153 } else if (ret < 0)
2154 goto out_disable;
2155 /* Just return zero, not the number of enabled functions */
2156 ret = 0;
2157 out:
2158 mutex_unlock(&event_mutex);
2159 return ret;
2160
2161 out_disable:
2162 __ftrace_event_enable_disable(file, 0, 1);
2163 out_put:
2164 module_put(file->event_call->mod);
2165 out_free:
2166 kfree(data);
2167 goto out;
2168 }
2169
2170 static struct ftrace_func_command event_enable_cmd = {
2171 .name = ENABLE_EVENT_STR,
2172 .func = event_enable_func,
2173 };
2174
2175 static struct ftrace_func_command event_disable_cmd = {
2176 .name = DISABLE_EVENT_STR,
2177 .func = event_enable_func,
2178 };
2179
2180 static __init int register_event_cmds(void)
2181 {
2182 int ret;
2183
2184 ret = register_ftrace_command(&event_enable_cmd);
2185 if (WARN_ON(ret < 0))
2186 return ret;
2187 ret = register_ftrace_command(&event_disable_cmd);
2188 if (WARN_ON(ret < 0))
2189 unregister_ftrace_command(&event_enable_cmd);
2190 return ret;
2191 }
2192 #else
2193 static inline int register_event_cmds(void) { return 0; }
2194 #endif /* CONFIG_DYNAMIC_FTRACE */
2195
2196 /*
2197 * The top level array has already had its ftrace_event_file
2198 * descriptors created in order to allow for early events to
2199 * be recorded. This function is called after the debugfs has been
2200 * initialized, and we now have to create the files associated
2201 * to the events.
2202 */
2203 static __init void
2204 __trace_early_add_event_dirs(struct trace_array *tr)
2205 {
2206 struct ftrace_event_file *file;
2207 int ret;
2208
2209
2210 list_for_each_entry(file, &tr->events, list) {
2211 ret = event_create_dir(tr->event_dir, file);
2212 if (ret < 0)
2213 pr_warn("Could not create directory for event %s\n",
2214 ftrace_event_name(file->event_call));
2215 }
2216 }
2217
2218 /*
2219 * For early boot up, the top trace array requires to have
2220 * a list of events that can be enabled. This must be done before
2221 * the filesystem is set up in order to allow events to be traced
2222 * early.
2223 */
2224 static __init void
2225 __trace_early_add_events(struct trace_array *tr)
2226 {
2227 struct ftrace_event_call *call;
2228 int ret;
2229
2230 list_for_each_entry(call, &ftrace_events, list) {
2231 /* Early boot up should not have any modules loaded */
2232 if (WARN_ON_ONCE(call->mod))
2233 continue;
2234
2235 ret = __trace_early_add_new_event(call, tr);
2236 if (ret < 0)
2237 pr_warn("Could not create early event %s\n",
2238 ftrace_event_name(call));
2239 }
2240 }
2241
2242 /* Remove the event directory structure for a trace directory. */
2243 static void
2244 __trace_remove_event_dirs(struct trace_array *tr)
2245 {
2246 struct ftrace_event_file *file, *next;
2247
2248 list_for_each_entry_safe(file, next, &tr->events, list)
2249 remove_event_file_dir(file);
2250 }
2251
2252 static void __add_event_to_tracers(struct ftrace_event_call *call)
2253 {
2254 struct trace_array *tr;
2255
2256 list_for_each_entry(tr, &ftrace_trace_arrays, list)
2257 __trace_add_new_event(call, tr);
2258 }
2259
2260 extern struct ftrace_event_call *__start_ftrace_events[];
2261 extern struct ftrace_event_call *__stop_ftrace_events[];
2262
2263 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2264
2265 static __init int setup_trace_event(char *str)
2266 {
2267 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2268 ring_buffer_expanded = true;
2269 tracing_selftest_disabled = true;
2270
2271 return 1;
2272 }
2273 __setup("trace_event=", setup_trace_event);
2274
2275 /* Expects to have event_mutex held when called */
2276 static int
2277 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2278 {
2279 struct dentry *d_events;
2280 struct dentry *entry;
2281
2282 entry = debugfs_create_file("set_event", 0644, parent,
2283 tr, &ftrace_set_event_fops);
2284 if (!entry) {
2285 pr_warn("Could not create debugfs 'set_event' entry\n");
2286 return -ENOMEM;
2287 }
2288
2289 d_events = debugfs_create_dir("events", parent);
2290 if (!d_events) {
2291 pr_warn("Could not create debugfs 'events' directory\n");
2292 return -ENOMEM;
2293 }
2294
2295 /* ring buffer internal formats */
2296 trace_create_file("header_page", 0444, d_events,
2297 ring_buffer_print_page_header,
2298 &ftrace_show_header_fops);
2299
2300 trace_create_file("header_event", 0444, d_events,
2301 ring_buffer_print_entry_header,
2302 &ftrace_show_header_fops);
2303
2304 trace_create_file("enable", 0644, d_events,
2305 tr, &ftrace_tr_enable_fops);
2306
2307 tr->event_dir = d_events;
2308
2309 return 0;
2310 }
2311
2312 /**
2313 * event_trace_add_tracer - add a instance of a trace_array to events
2314 * @parent: The parent dentry to place the files/directories for events in
2315 * @tr: The trace array associated with these events
2316 *
2317 * When a new instance is created, it needs to set up its events
2318 * directory, as well as other files associated with events. It also
2319 * creates the event hierachry in the @parent/events directory.
2320 *
2321 * Returns 0 on success.
2322 */
2323 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2324 {
2325 int ret;
2326
2327 mutex_lock(&event_mutex);
2328
2329 ret = create_event_toplevel_files(parent, tr);
2330 if (ret)
2331 goto out_unlock;
2332
2333 down_write(&trace_event_sem);
2334 __trace_add_event_dirs(tr);
2335 up_write(&trace_event_sem);
2336
2337 out_unlock:
2338 mutex_unlock(&event_mutex);
2339
2340 return ret;
2341 }
2342
2343 /*
2344 * The top trace array already had its file descriptors created.
2345 * Now the files themselves need to be created.
2346 */
2347 static __init int
2348 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2349 {
2350 int ret;
2351
2352 mutex_lock(&event_mutex);
2353
2354 ret = create_event_toplevel_files(parent, tr);
2355 if (ret)
2356 goto out_unlock;
2357
2358 down_write(&trace_event_sem);
2359 __trace_early_add_event_dirs(tr);
2360 up_write(&trace_event_sem);
2361
2362 out_unlock:
2363 mutex_unlock(&event_mutex);
2364
2365 return ret;
2366 }
2367
2368 int event_trace_del_tracer(struct trace_array *tr)
2369 {
2370 mutex_lock(&event_mutex);
2371
2372 /* Disable any event triggers and associated soft-disabled events */
2373 clear_event_triggers(tr);
2374
2375 /* Disable any running events */
2376 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
2377
2378 /* Access to events are within rcu_read_lock_sched() */
2379 synchronize_sched();
2380
2381 down_write(&trace_event_sem);
2382 __trace_remove_event_dirs(tr);
2383 debugfs_remove_recursive(tr->event_dir);
2384 up_write(&trace_event_sem);
2385
2386 tr->event_dir = NULL;
2387
2388 mutex_unlock(&event_mutex);
2389
2390 return 0;
2391 }
2392
2393 static __init int event_trace_memsetup(void)
2394 {
2395 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
2396 file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC);
2397 return 0;
2398 }
2399
2400 static __init int event_trace_enable(void)
2401 {
2402 struct trace_array *tr = top_trace_array();
2403 struct ftrace_event_call **iter, *call;
2404 char *buf = bootup_event_buf;
2405 char *token;
2406 int ret;
2407
2408 if (!tr)
2409 return -ENODEV;
2410
2411 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
2412
2413 call = *iter;
2414 ret = event_init(call);
2415 if (!ret)
2416 list_add(&call->list, &ftrace_events);
2417 }
2418
2419 /*
2420 * We need the top trace array to have a working set of trace
2421 * points at early init, before the debug files and directories
2422 * are created. Create the file entries now, and attach them
2423 * to the actual file dentries later.
2424 */
2425 __trace_early_add_events(tr);
2426
2427 while (true) {
2428 token = strsep(&buf, ",");
2429
2430 if (!token)
2431 break;
2432 if (!*token)
2433 continue;
2434
2435 ret = ftrace_set_clr_event(tr, token, 1);
2436 if (ret)
2437 pr_warn("Failed to enable trace event: %s\n", token);
2438 }
2439
2440 trace_printk_start_comm();
2441
2442 register_event_cmds();
2443
2444 register_trigger_cmds();
2445
2446 return 0;
2447 }
2448
2449 static __init int event_trace_init(void)
2450 {
2451 struct trace_array *tr;
2452 struct dentry *d_tracer;
2453 struct dentry *entry;
2454 int ret;
2455
2456 tr = top_trace_array();
2457 if (!tr)
2458 return -ENODEV;
2459
2460 d_tracer = tracing_init_dentry();
2461 if (!d_tracer)
2462 return 0;
2463
2464 entry = debugfs_create_file("available_events", 0444, d_tracer,
2465 tr, &ftrace_avail_fops);
2466 if (!entry)
2467 pr_warn("Could not create debugfs 'available_events' entry\n");
2468
2469 if (trace_define_common_fields())
2470 pr_warn("tracing: Failed to allocate common fields");
2471
2472 ret = early_event_add_tracer(d_tracer, tr);
2473 if (ret)
2474 return ret;
2475
2476 #ifdef CONFIG_MODULES
2477 ret = register_module_notifier(&trace_module_nb);
2478 if (ret)
2479 pr_warn("Failed to register trace events module notifier\n");
2480 #endif
2481 return 0;
2482 }
2483 early_initcall(event_trace_memsetup);
2484 core_initcall(event_trace_enable);
2485 fs_initcall(event_trace_init);
2486
2487 #ifdef CONFIG_FTRACE_STARTUP_TEST
2488
2489 static DEFINE_SPINLOCK(test_spinlock);
2490 static DEFINE_SPINLOCK(test_spinlock_irq);
2491 static DEFINE_MUTEX(test_mutex);
2492
2493 static __init void test_work(struct work_struct *dummy)
2494 {
2495 spin_lock(&test_spinlock);
2496 spin_lock_irq(&test_spinlock_irq);
2497 udelay(1);
2498 spin_unlock_irq(&test_spinlock_irq);
2499 spin_unlock(&test_spinlock);
2500
2501 mutex_lock(&test_mutex);
2502 msleep(1);
2503 mutex_unlock(&test_mutex);
2504 }
2505
2506 static __init int event_test_thread(void *unused)
2507 {
2508 void *test_malloc;
2509
2510 test_malloc = kmalloc(1234, GFP_KERNEL);
2511 if (!test_malloc)
2512 pr_info("failed to kmalloc\n");
2513
2514 schedule_on_each_cpu(test_work);
2515
2516 kfree(test_malloc);
2517
2518 set_current_state(TASK_INTERRUPTIBLE);
2519 while (!kthread_should_stop()) {
2520 schedule();
2521 set_current_state(TASK_INTERRUPTIBLE);
2522 }
2523 __set_current_state(TASK_RUNNING);
2524
2525 return 0;
2526 }
2527
2528 /*
2529 * Do various things that may trigger events.
2530 */
2531 static __init void event_test_stuff(void)
2532 {
2533 struct task_struct *test_thread;
2534
2535 test_thread = kthread_run(event_test_thread, NULL, "test-events");
2536 msleep(1);
2537 kthread_stop(test_thread);
2538 }
2539
2540 /*
2541 * For every trace event defined, we will test each trace point separately,
2542 * and then by groups, and finally all trace points.
2543 */
2544 static __init void event_trace_self_tests(void)
2545 {
2546 struct ftrace_subsystem_dir *dir;
2547 struct ftrace_event_file *file;
2548 struct ftrace_event_call *call;
2549 struct event_subsystem *system;
2550 struct trace_array *tr;
2551 int ret;
2552
2553 tr = top_trace_array();
2554 if (!tr)
2555 return;
2556
2557 pr_info("Running tests on trace events:\n");
2558
2559 list_for_each_entry(file, &tr->events, list) {
2560
2561 call = file->event_call;
2562
2563 /* Only test those that have a probe */
2564 if (!call->class || !call->class->probe)
2565 continue;
2566
2567 /*
2568 * Testing syscall events here is pretty useless, but
2569 * we still do it if configured. But this is time consuming.
2570 * What we really need is a user thread to perform the
2571 * syscalls as we test.
2572 */
2573 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
2574 if (call->class->system &&
2575 strcmp(call->class->system, "syscalls") == 0)
2576 continue;
2577 #endif
2578
2579 pr_info("Testing event %s: ", ftrace_event_name(call));
2580
2581 /*
2582 * If an event is already enabled, someone is using
2583 * it and the self test should not be on.
2584 */
2585 if (file->flags & FTRACE_EVENT_FL_ENABLED) {
2586 pr_warn("Enabled event during self test!\n");
2587 WARN_ON_ONCE(1);
2588 continue;
2589 }
2590
2591 ftrace_event_enable_disable(file, 1);
2592 event_test_stuff();
2593 ftrace_event_enable_disable(file, 0);
2594
2595 pr_cont("OK\n");
2596 }
2597
2598 /* Now test at the sub system level */
2599
2600 pr_info("Running tests on trace event systems:\n");
2601
2602 list_for_each_entry(dir, &tr->systems, list) {
2603
2604 system = dir->subsystem;
2605
2606 /* the ftrace system is special, skip it */
2607 if (strcmp(system->name, "ftrace") == 0)
2608 continue;
2609
2610 pr_info("Testing event system %s: ", system->name);
2611
2612 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
2613 if (WARN_ON_ONCE(ret)) {
2614 pr_warn("error enabling system %s\n",
2615 system->name);
2616 continue;
2617 }
2618
2619 event_test_stuff();
2620
2621 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
2622 if (WARN_ON_ONCE(ret)) {
2623 pr_warn("error disabling system %s\n",
2624 system->name);
2625 continue;
2626 }
2627
2628 pr_cont("OK\n");
2629 }
2630
2631 /* Test with all events enabled */
2632
2633 pr_info("Running tests on all trace events:\n");
2634 pr_info("Testing all events: ");
2635
2636 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
2637 if (WARN_ON_ONCE(ret)) {
2638 pr_warn("error enabling all events\n");
2639 return;
2640 }
2641
2642 event_test_stuff();
2643
2644 /* reset sysname */
2645 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
2646 if (WARN_ON_ONCE(ret)) {
2647 pr_warn("error disabling all events\n");
2648 return;
2649 }
2650
2651 pr_cont("OK\n");
2652 }
2653
2654 #ifdef CONFIG_FUNCTION_TRACER
2655
2656 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
2657
2658 static void
2659 function_test_events_call(unsigned long ip, unsigned long parent_ip,
2660 struct ftrace_ops *op, struct pt_regs *pt_regs)
2661 {
2662 struct ring_buffer_event *event;
2663 struct ring_buffer *buffer;
2664 struct ftrace_entry *entry;
2665 unsigned long flags;
2666 long disabled;
2667 int cpu;
2668 int pc;
2669
2670 pc = preempt_count();
2671 preempt_disable_notrace();
2672 cpu = raw_smp_processor_id();
2673 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
2674
2675 if (disabled != 1)
2676 goto out;
2677
2678 local_save_flags(flags);
2679
2680 event = trace_current_buffer_lock_reserve(&buffer,
2681 TRACE_FN, sizeof(*entry),
2682 flags, pc);
2683 if (!event)
2684 goto out;
2685 entry = ring_buffer_event_data(event);
2686 entry->ip = ip;
2687 entry->parent_ip = parent_ip;
2688
2689 trace_buffer_unlock_commit(buffer, event, flags, pc);
2690
2691 out:
2692 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
2693 preempt_enable_notrace();
2694 }
2695
2696 static struct ftrace_ops trace_ops __initdata =
2697 {
2698 .func = function_test_events_call,
2699 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
2700 };
2701
2702 static __init void event_trace_self_test_with_function(void)
2703 {
2704 int ret;
2705 ret = register_ftrace_function(&trace_ops);
2706 if (WARN_ON(ret < 0)) {
2707 pr_info("Failed to enable function tracer for event tests\n");
2708 return;
2709 }
2710 pr_info("Running tests again, along with the function tracer\n");
2711 event_trace_self_tests();
2712 unregister_ftrace_function(&trace_ops);
2713 }
2714 #else
2715 static __init void event_trace_self_test_with_function(void)
2716 {
2717 }
2718 #endif
2719
2720 static __init int event_trace_self_tests_init(void)
2721 {
2722 if (!tracing_selftest_disabled) {
2723 event_trace_self_tests();
2724 event_trace_self_test_with_function();
2725 }
2726
2727 return 0;
2728 }
2729
2730 late_initcall(event_trace_self_tests_init);
2731
2732 #endif
Linux kernel - Deliverables
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