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Merge tag 'drm-intel-next-fixes-2014-12-30' of git://anongit.freedesktop.org/drm...
[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 static DEFINE_SPINLOCK(tracepoint_iter_lock);
216
217 static void output_printk(struct ftrace_event_buffer *fbuffer)
218 {
219 struct ftrace_event_call *event_call;
220 struct trace_event *event;
221 unsigned long flags;
222 struct trace_iterator *iter = tracepoint_print_iter;
223
224 if (!iter)
225 return;
226
227 event_call = fbuffer->ftrace_file->event_call;
228 if (!event_call || !event_call->event.funcs ||
229 !event_call->event.funcs->trace)
230 return;
231
232 event = &fbuffer->ftrace_file->event_call->event;
233
234 spin_lock_irqsave(&tracepoint_iter_lock, flags);
235 trace_seq_init(&iter->seq);
236 iter->ent = fbuffer->entry;
237 event_call->event.funcs->trace(iter, 0, event);
238 trace_seq_putc(&iter->seq, 0);
239 printk("%s", iter->seq.buffer);
240
241 spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
242 }
243
244 void ftrace_event_buffer_commit(struct ftrace_event_buffer *fbuffer)
245 {
246 if (tracepoint_printk)
247 output_printk(fbuffer);
248
249 event_trigger_unlock_commit(fbuffer->ftrace_file, fbuffer->buffer,
250 fbuffer->event, fbuffer->entry,
251 fbuffer->flags, fbuffer->pc);
252 }
253 EXPORT_SYMBOL_GPL(ftrace_event_buffer_commit);
254
255 int ftrace_event_reg(struct ftrace_event_call *call,
256 enum trace_reg type, void *data)
257 {
258 struct ftrace_event_file *file = data;
259
260 WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
261 switch (type) {
262 case TRACE_REG_REGISTER:
263 return tracepoint_probe_register(call->tp,
264 call->class->probe,
265 file);
266 case TRACE_REG_UNREGISTER:
267 tracepoint_probe_unregister(call->tp,
268 call->class->probe,
269 file);
270 return 0;
271
272 #ifdef CONFIG_PERF_EVENTS
273 case TRACE_REG_PERF_REGISTER:
274 return tracepoint_probe_register(call->tp,
275 call->class->perf_probe,
276 call);
277 case TRACE_REG_PERF_UNREGISTER:
278 tracepoint_probe_unregister(call->tp,
279 call->class->perf_probe,
280 call);
281 return 0;
282 case TRACE_REG_PERF_OPEN:
283 case TRACE_REG_PERF_CLOSE:
284 case TRACE_REG_PERF_ADD:
285 case TRACE_REG_PERF_DEL:
286 return 0;
287 #endif
288 }
289 return 0;
290 }
291 EXPORT_SYMBOL_GPL(ftrace_event_reg);
292
293 void trace_event_enable_cmd_record(bool enable)
294 {
295 struct ftrace_event_file *file;
296 struct trace_array *tr;
297
298 mutex_lock(&event_mutex);
299 do_for_each_event_file(tr, file) {
300
301 if (!(file->flags & FTRACE_EVENT_FL_ENABLED))
302 continue;
303
304 if (enable) {
305 tracing_start_cmdline_record();
306 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
307 } else {
308 tracing_stop_cmdline_record();
309 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
310 }
311 } while_for_each_event_file();
312 mutex_unlock(&event_mutex);
313 }
314
315 static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
316 int enable, int soft_disable)
317 {
318 struct ftrace_event_call *call = file->event_call;
319 int ret = 0;
320 int disable;
321
322 switch (enable) {
323 case 0:
324 /*
325 * When soft_disable is set and enable is cleared, the sm_ref
326 * reference counter is decremented. If it reaches 0, we want
327 * to clear the SOFT_DISABLED flag but leave the event in the
328 * state that it was. That is, if the event was enabled and
329 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
330 * is set we do not want the event to be enabled before we
331 * clear the bit.
332 *
333 * When soft_disable is not set but the SOFT_MODE flag is,
334 * we do nothing. Do not disable the tracepoint, otherwise
335 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
336 */
337 if (soft_disable) {
338 if (atomic_dec_return(&file->sm_ref) > 0)
339 break;
340 disable = file->flags & FTRACE_EVENT_FL_SOFT_DISABLED;
341 clear_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
342 } else
343 disable = !(file->flags & FTRACE_EVENT_FL_SOFT_MODE);
344
345 if (disable && (file->flags & FTRACE_EVENT_FL_ENABLED)) {
346 clear_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
347 if (file->flags & FTRACE_EVENT_FL_RECORDED_CMD) {
348 tracing_stop_cmdline_record();
349 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
350 }
351 call->class->reg(call, TRACE_REG_UNREGISTER, file);
352 }
353 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
354 if (file->flags & FTRACE_EVENT_FL_SOFT_MODE)
355 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
356 else
357 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
358 break;
359 case 1:
360 /*
361 * When soft_disable is set and enable is set, we want to
362 * register the tracepoint for the event, but leave the event
363 * as is. That means, if the event was already enabled, we do
364 * nothing (but set SOFT_MODE). If the event is disabled, we
365 * set SOFT_DISABLED before enabling the event tracepoint, so
366 * it still seems to be disabled.
367 */
368 if (!soft_disable)
369 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
370 else {
371 if (atomic_inc_return(&file->sm_ref) > 1)
372 break;
373 set_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
374 }
375
376 if (!(file->flags & FTRACE_EVENT_FL_ENABLED)) {
377
378 /* Keep the event disabled, when going to SOFT_MODE. */
379 if (soft_disable)
380 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
381
382 if (trace_flags & TRACE_ITER_RECORD_CMD) {
383 tracing_start_cmdline_record();
384 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
385 }
386 ret = call->class->reg(call, TRACE_REG_REGISTER, file);
387 if (ret) {
388 tracing_stop_cmdline_record();
389 pr_info("event trace: Could not enable event "
390 "%s\n", ftrace_event_name(call));
391 break;
392 }
393 set_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
394
395 /* WAS_ENABLED gets set but never cleared. */
396 call->flags |= TRACE_EVENT_FL_WAS_ENABLED;
397 }
398 break;
399 }
400
401 return ret;
402 }
403
404 int trace_event_enable_disable(struct ftrace_event_file *file,
405 int enable, int soft_disable)
406 {
407 return __ftrace_event_enable_disable(file, enable, soft_disable);
408 }
409
410 static int ftrace_event_enable_disable(struct ftrace_event_file *file,
411 int enable)
412 {
413 return __ftrace_event_enable_disable(file, enable, 0);
414 }
415
416 static void ftrace_clear_events(struct trace_array *tr)
417 {
418 struct ftrace_event_file *file;
419
420 mutex_lock(&event_mutex);
421 list_for_each_entry(file, &tr->events, list) {
422 ftrace_event_enable_disable(file, 0);
423 }
424 mutex_unlock(&event_mutex);
425 }
426
427 static void __put_system(struct event_subsystem *system)
428 {
429 struct event_filter *filter = system->filter;
430
431 WARN_ON_ONCE(system_refcount(system) == 0);
432 if (system_refcount_dec(system))
433 return;
434
435 list_del(&system->list);
436
437 if (filter) {
438 kfree(filter->filter_string);
439 kfree(filter);
440 }
441 if (system->ref_count & SYSTEM_FL_FREE_NAME)
442 kfree(system->name);
443 kfree(system);
444 }
445
446 static void __get_system(struct event_subsystem *system)
447 {
448 WARN_ON_ONCE(system_refcount(system) == 0);
449 system_refcount_inc(system);
450 }
451
452 static void __get_system_dir(struct ftrace_subsystem_dir *dir)
453 {
454 WARN_ON_ONCE(dir->ref_count == 0);
455 dir->ref_count++;
456 __get_system(dir->subsystem);
457 }
458
459 static void __put_system_dir(struct ftrace_subsystem_dir *dir)
460 {
461 WARN_ON_ONCE(dir->ref_count == 0);
462 /* If the subsystem is about to be freed, the dir must be too */
463 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
464
465 __put_system(dir->subsystem);
466 if (!--dir->ref_count)
467 kfree(dir);
468 }
469
470 static void put_system(struct ftrace_subsystem_dir *dir)
471 {
472 mutex_lock(&event_mutex);
473 __put_system_dir(dir);
474 mutex_unlock(&event_mutex);
475 }
476
477 static void remove_subsystem(struct ftrace_subsystem_dir *dir)
478 {
479 if (!dir)
480 return;
481
482 if (!--dir->nr_events) {
483 debugfs_remove_recursive(dir->entry);
484 list_del(&dir->list);
485 __put_system_dir(dir);
486 }
487 }
488
489 static void remove_event_file_dir(struct ftrace_event_file *file)
490 {
491 struct dentry *dir = file->dir;
492 struct dentry *child;
493
494 if (dir) {
495 spin_lock(&dir->d_lock); /* probably unneeded */
496 list_for_each_entry(child, &dir->d_subdirs, d_child) {
497 if (child->d_inode) /* probably unneeded */
498 child->d_inode->i_private = NULL;
499 }
500 spin_unlock(&dir->d_lock);
501
502 debugfs_remove_recursive(dir);
503 }
504
505 list_del(&file->list);
506 remove_subsystem(file->system);
507 free_event_filter(file->filter);
508 kmem_cache_free(file_cachep, file);
509 }
510
511 /*
512 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
513 */
514 static int
515 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
516 const char *sub, const char *event, int set)
517 {
518 struct ftrace_event_file *file;
519 struct ftrace_event_call *call;
520 const char *name;
521 int ret = -EINVAL;
522
523 list_for_each_entry(file, &tr->events, list) {
524
525 call = file->event_call;
526 name = ftrace_event_name(call);
527
528 if (!name || !call->class || !call->class->reg)
529 continue;
530
531 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
532 continue;
533
534 if (match &&
535 strcmp(match, name) != 0 &&
536 strcmp(match, call->class->system) != 0)
537 continue;
538
539 if (sub && strcmp(sub, call->class->system) != 0)
540 continue;
541
542 if (event && strcmp(event, name) != 0)
543 continue;
544
545 ftrace_event_enable_disable(file, set);
546
547 ret = 0;
548 }
549
550 return ret;
551 }
552
553 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
554 const char *sub, const char *event, int set)
555 {
556 int ret;
557
558 mutex_lock(&event_mutex);
559 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
560 mutex_unlock(&event_mutex);
561
562 return ret;
563 }
564
565 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
566 {
567 char *event = NULL, *sub = NULL, *match;
568
569 /*
570 * The buf format can be <subsystem>:<event-name>
571 * *:<event-name> means any event by that name.
572 * :<event-name> is the same.
573 *
574 * <subsystem>:* means all events in that subsystem
575 * <subsystem>: means the same.
576 *
577 * <name> (no ':') means all events in a subsystem with
578 * the name <name> or any event that matches <name>
579 */
580
581 match = strsep(&buf, ":");
582 if (buf) {
583 sub = match;
584 event = buf;
585 match = NULL;
586
587 if (!strlen(sub) || strcmp(sub, "*") == 0)
588 sub = NULL;
589 if (!strlen(event) || strcmp(event, "*") == 0)
590 event = NULL;
591 }
592
593 return __ftrace_set_clr_event(tr, match, sub, event, set);
594 }
595
596 /**
597 * trace_set_clr_event - enable or disable an event
598 * @system: system name to match (NULL for any system)
599 * @event: event name to match (NULL for all events, within system)
600 * @set: 1 to enable, 0 to disable
601 *
602 * This is a way for other parts of the kernel to enable or disable
603 * event recording.
604 *
605 * Returns 0 on success, -EINVAL if the parameters do not match any
606 * registered events.
607 */
608 int trace_set_clr_event(const char *system, const char *event, int set)
609 {
610 struct trace_array *tr = top_trace_array();
611
612 if (!tr)
613 return -ENODEV;
614
615 return __ftrace_set_clr_event(tr, NULL, system, event, set);
616 }
617 EXPORT_SYMBOL_GPL(trace_set_clr_event);
618
619 /* 128 should be much more than enough */
620 #define EVENT_BUF_SIZE 127
621
622 static ssize_t
623 ftrace_event_write(struct file *file, const char __user *ubuf,
624 size_t cnt, loff_t *ppos)
625 {
626 struct trace_parser parser;
627 struct seq_file *m = file->private_data;
628 struct trace_array *tr = m->private;
629 ssize_t read, ret;
630
631 if (!cnt)
632 return 0;
633
634 ret = tracing_update_buffers();
635 if (ret < 0)
636 return ret;
637
638 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
639 return -ENOMEM;
640
641 read = trace_get_user(&parser, ubuf, cnt, ppos);
642
643 if (read >= 0 && trace_parser_loaded((&parser))) {
644 int set = 1;
645
646 if (*parser.buffer == '!')
647 set = 0;
648
649 parser.buffer[parser.idx] = 0;
650
651 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
652 if (ret)
653 goto out_put;
654 }
655
656 ret = read;
657
658 out_put:
659 trace_parser_put(&parser);
660
661 return ret;
662 }
663
664 static void *
665 t_next(struct seq_file *m, void *v, loff_t *pos)
666 {
667 struct ftrace_event_file *file = v;
668 struct ftrace_event_call *call;
669 struct trace_array *tr = m->private;
670
671 (*pos)++;
672
673 list_for_each_entry_continue(file, &tr->events, list) {
674 call = file->event_call;
675 /*
676 * The ftrace subsystem is for showing formats only.
677 * They can not be enabled or disabled via the event files.
678 */
679 if (call->class && call->class->reg)
680 return file;
681 }
682
683 return NULL;
684 }
685
686 static void *t_start(struct seq_file *m, loff_t *pos)
687 {
688 struct ftrace_event_file *file;
689 struct trace_array *tr = m->private;
690 loff_t l;
691
692 mutex_lock(&event_mutex);
693
694 file = list_entry(&tr->events, struct ftrace_event_file, list);
695 for (l = 0; l <= *pos; ) {
696 file = t_next(m, file, &l);
697 if (!file)
698 break;
699 }
700 return file;
701 }
702
703 static void *
704 s_next(struct seq_file *m, void *v, loff_t *pos)
705 {
706 struct ftrace_event_file *file = v;
707 struct trace_array *tr = m->private;
708
709 (*pos)++;
710
711 list_for_each_entry_continue(file, &tr->events, list) {
712 if (file->flags & FTRACE_EVENT_FL_ENABLED)
713 return file;
714 }
715
716 return NULL;
717 }
718
719 static void *s_start(struct seq_file *m, loff_t *pos)
720 {
721 struct ftrace_event_file *file;
722 struct trace_array *tr = m->private;
723 loff_t l;
724
725 mutex_lock(&event_mutex);
726
727 file = list_entry(&tr->events, struct ftrace_event_file, list);
728 for (l = 0; l <= *pos; ) {
729 file = s_next(m, file, &l);
730 if (!file)
731 break;
732 }
733 return file;
734 }
735
736 static int t_show(struct seq_file *m, void *v)
737 {
738 struct ftrace_event_file *file = v;
739 struct ftrace_event_call *call = file->event_call;
740
741 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
742 seq_printf(m, "%s:", call->class->system);
743 seq_printf(m, "%s\n", ftrace_event_name(call));
744
745 return 0;
746 }
747
748 static void t_stop(struct seq_file *m, void *p)
749 {
750 mutex_unlock(&event_mutex);
751 }
752
753 static ssize_t
754 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
755 loff_t *ppos)
756 {
757 struct ftrace_event_file *file;
758 unsigned long flags;
759 char buf[4] = "0";
760
761 mutex_lock(&event_mutex);
762 file = event_file_data(filp);
763 if (likely(file))
764 flags = file->flags;
765 mutex_unlock(&event_mutex);
766
767 if (!file)
768 return -ENODEV;
769
770 if (flags & FTRACE_EVENT_FL_ENABLED &&
771 !(flags & FTRACE_EVENT_FL_SOFT_DISABLED))
772 strcpy(buf, "1");
773
774 if (flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
775 flags & FTRACE_EVENT_FL_SOFT_MODE)
776 strcat(buf, "*");
777
778 strcat(buf, "\n");
779
780 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
781 }
782
783 static ssize_t
784 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
785 loff_t *ppos)
786 {
787 struct ftrace_event_file *file;
788 unsigned long val;
789 int ret;
790
791 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
792 if (ret)
793 return ret;
794
795 ret = tracing_update_buffers();
796 if (ret < 0)
797 return ret;
798
799 switch (val) {
800 case 0:
801 case 1:
802 ret = -ENODEV;
803 mutex_lock(&event_mutex);
804 file = event_file_data(filp);
805 if (likely(file))
806 ret = ftrace_event_enable_disable(file, val);
807 mutex_unlock(&event_mutex);
808 break;
809
810 default:
811 return -EINVAL;
812 }
813
814 *ppos += cnt;
815
816 return ret ? ret : cnt;
817 }
818
819 static ssize_t
820 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
821 loff_t *ppos)
822 {
823 const char set_to_char[4] = { '?', '0', '1', 'X' };
824 struct ftrace_subsystem_dir *dir = filp->private_data;
825 struct event_subsystem *system = dir->subsystem;
826 struct ftrace_event_call *call;
827 struct ftrace_event_file *file;
828 struct trace_array *tr = dir->tr;
829 char buf[2];
830 int set = 0;
831 int ret;
832
833 mutex_lock(&event_mutex);
834 list_for_each_entry(file, &tr->events, list) {
835 call = file->event_call;
836 if (!ftrace_event_name(call) || !call->class || !call->class->reg)
837 continue;
838
839 if (system && strcmp(call->class->system, system->name) != 0)
840 continue;
841
842 /*
843 * We need to find out if all the events are set
844 * or if all events or cleared, or if we have
845 * a mixture.
846 */
847 set |= (1 << !!(file->flags & FTRACE_EVENT_FL_ENABLED));
848
849 /*
850 * If we have a mixture, no need to look further.
851 */
852 if (set == 3)
853 break;
854 }
855 mutex_unlock(&event_mutex);
856
857 buf[0] = set_to_char[set];
858 buf[1] = '\n';
859
860 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
861
862 return ret;
863 }
864
865 static ssize_t
866 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
867 loff_t *ppos)
868 {
869 struct ftrace_subsystem_dir *dir = filp->private_data;
870 struct event_subsystem *system = dir->subsystem;
871 const char *name = NULL;
872 unsigned long val;
873 ssize_t ret;
874
875 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
876 if (ret)
877 return ret;
878
879 ret = tracing_update_buffers();
880 if (ret < 0)
881 return ret;
882
883 if (val != 0 && val != 1)
884 return -EINVAL;
885
886 /*
887 * Opening of "enable" adds a ref count to system,
888 * so the name is safe to use.
889 */
890 if (system)
891 name = system->name;
892
893 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
894 if (ret)
895 goto out;
896
897 ret = cnt;
898
899 out:
900 *ppos += cnt;
901
902 return ret;
903 }
904
905 enum {
906 FORMAT_HEADER = 1,
907 FORMAT_FIELD_SEPERATOR = 2,
908 FORMAT_PRINTFMT = 3,
909 };
910
911 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
912 {
913 struct ftrace_event_call *call = event_file_data(m->private);
914 struct list_head *common_head = &ftrace_common_fields;
915 struct list_head *head = trace_get_fields(call);
916 struct list_head *node = v;
917
918 (*pos)++;
919
920 switch ((unsigned long)v) {
921 case FORMAT_HEADER:
922 node = common_head;
923 break;
924
925 case FORMAT_FIELD_SEPERATOR:
926 node = head;
927 break;
928
929 case FORMAT_PRINTFMT:
930 /* all done */
931 return NULL;
932 }
933
934 node = node->prev;
935 if (node == common_head)
936 return (void *)FORMAT_FIELD_SEPERATOR;
937 else if (node == head)
938 return (void *)FORMAT_PRINTFMT;
939 else
940 return node;
941 }
942
943 static int f_show(struct seq_file *m, void *v)
944 {
945 struct ftrace_event_call *call = event_file_data(m->private);
946 struct ftrace_event_field *field;
947 const char *array_descriptor;
948
949 switch ((unsigned long)v) {
950 case FORMAT_HEADER:
951 seq_printf(m, "name: %s\n", ftrace_event_name(call));
952 seq_printf(m, "ID: %d\n", call->event.type);
953 seq_puts(m, "format:\n");
954 return 0;
955
956 case FORMAT_FIELD_SEPERATOR:
957 seq_putc(m, '\n');
958 return 0;
959
960 case FORMAT_PRINTFMT:
961 seq_printf(m, "\nprint fmt: %s\n",
962 call->print_fmt);
963 return 0;
964 }
965
966 field = list_entry(v, struct ftrace_event_field, link);
967 /*
968 * Smartly shows the array type(except dynamic array).
969 * Normal:
970 * field:TYPE VAR
971 * If TYPE := TYPE[LEN], it is shown:
972 * field:TYPE VAR[LEN]
973 */
974 array_descriptor = strchr(field->type, '[');
975
976 if (!strncmp(field->type, "__data_loc", 10))
977 array_descriptor = NULL;
978
979 if (!array_descriptor)
980 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
981 field->type, field->name, field->offset,
982 field->size, !!field->is_signed);
983 else
984 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
985 (int)(array_descriptor - field->type),
986 field->type, field->name,
987 array_descriptor, field->offset,
988 field->size, !!field->is_signed);
989
990 return 0;
991 }
992
993 static void *f_start(struct seq_file *m, loff_t *pos)
994 {
995 void *p = (void *)FORMAT_HEADER;
996 loff_t l = 0;
997
998 /* ->stop() is called even if ->start() fails */
999 mutex_lock(&event_mutex);
1000 if (!event_file_data(m->private))
1001 return ERR_PTR(-ENODEV);
1002
1003 while (l < *pos && p)
1004 p = f_next(m, p, &l);
1005
1006 return p;
1007 }
1008
1009 static void f_stop(struct seq_file *m, void *p)
1010 {
1011 mutex_unlock(&event_mutex);
1012 }
1013
1014 static const struct seq_operations trace_format_seq_ops = {
1015 .start = f_start,
1016 .next = f_next,
1017 .stop = f_stop,
1018 .show = f_show,
1019 };
1020
1021 static int trace_format_open(struct inode *inode, struct file *file)
1022 {
1023 struct seq_file *m;
1024 int ret;
1025
1026 ret = seq_open(file, &trace_format_seq_ops);
1027 if (ret < 0)
1028 return ret;
1029
1030 m = file->private_data;
1031 m->private = file;
1032
1033 return 0;
1034 }
1035
1036 static ssize_t
1037 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1038 {
1039 int id = (long)event_file_data(filp);
1040 char buf[32];
1041 int len;
1042
1043 if (*ppos)
1044 return 0;
1045
1046 if (unlikely(!id))
1047 return -ENODEV;
1048
1049 len = sprintf(buf, "%d\n", id);
1050
1051 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1052 }
1053
1054 static ssize_t
1055 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1056 loff_t *ppos)
1057 {
1058 struct ftrace_event_file *file;
1059 struct trace_seq *s;
1060 int r = -ENODEV;
1061
1062 if (*ppos)
1063 return 0;
1064
1065 s = kmalloc(sizeof(*s), GFP_KERNEL);
1066
1067 if (!s)
1068 return -ENOMEM;
1069
1070 trace_seq_init(s);
1071
1072 mutex_lock(&event_mutex);
1073 file = event_file_data(filp);
1074 if (file)
1075 print_event_filter(file, s);
1076 mutex_unlock(&event_mutex);
1077
1078 if (file)
1079 r = simple_read_from_buffer(ubuf, cnt, ppos,
1080 s->buffer, trace_seq_used(s));
1081
1082 kfree(s);
1083
1084 return r;
1085 }
1086
1087 static ssize_t
1088 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1089 loff_t *ppos)
1090 {
1091 struct ftrace_event_file *file;
1092 char *buf;
1093 int err = -ENODEV;
1094
1095 if (cnt >= PAGE_SIZE)
1096 return -EINVAL;
1097
1098 buf = (char *)__get_free_page(GFP_TEMPORARY);
1099 if (!buf)
1100 return -ENOMEM;
1101
1102 if (copy_from_user(buf, ubuf, cnt)) {
1103 free_page((unsigned long) buf);
1104 return -EFAULT;
1105 }
1106 buf[cnt] = '\0';
1107
1108 mutex_lock(&event_mutex);
1109 file = event_file_data(filp);
1110 if (file)
1111 err = apply_event_filter(file, buf);
1112 mutex_unlock(&event_mutex);
1113
1114 free_page((unsigned long) buf);
1115 if (err < 0)
1116 return err;
1117
1118 *ppos += cnt;
1119
1120 return cnt;
1121 }
1122
1123 static LIST_HEAD(event_subsystems);
1124
1125 static int subsystem_open(struct inode *inode, struct file *filp)
1126 {
1127 struct event_subsystem *system = NULL;
1128 struct ftrace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1129 struct trace_array *tr;
1130 int ret;
1131
1132 if (tracing_is_disabled())
1133 return -ENODEV;
1134
1135 /* Make sure the system still exists */
1136 mutex_lock(&trace_types_lock);
1137 mutex_lock(&event_mutex);
1138 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1139 list_for_each_entry(dir, &tr->systems, list) {
1140 if (dir == inode->i_private) {
1141 /* Don't open systems with no events */
1142 if (dir->nr_events) {
1143 __get_system_dir(dir);
1144 system = dir->subsystem;
1145 }
1146 goto exit_loop;
1147 }
1148 }
1149 }
1150 exit_loop:
1151 mutex_unlock(&event_mutex);
1152 mutex_unlock(&trace_types_lock);
1153
1154 if (!system)
1155 return -ENODEV;
1156
1157 /* Some versions of gcc think dir can be uninitialized here */
1158 WARN_ON(!dir);
1159
1160 /* Still need to increment the ref count of the system */
1161 if (trace_array_get(tr) < 0) {
1162 put_system(dir);
1163 return -ENODEV;
1164 }
1165
1166 ret = tracing_open_generic(inode, filp);
1167 if (ret < 0) {
1168 trace_array_put(tr);
1169 put_system(dir);
1170 }
1171
1172 return ret;
1173 }
1174
1175 static int system_tr_open(struct inode *inode, struct file *filp)
1176 {
1177 struct ftrace_subsystem_dir *dir;
1178 struct trace_array *tr = inode->i_private;
1179 int ret;
1180
1181 if (tracing_is_disabled())
1182 return -ENODEV;
1183
1184 if (trace_array_get(tr) < 0)
1185 return -ENODEV;
1186
1187 /* Make a temporary dir that has no system but points to tr */
1188 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1189 if (!dir) {
1190 trace_array_put(tr);
1191 return -ENOMEM;
1192 }
1193
1194 dir->tr = tr;
1195
1196 ret = tracing_open_generic(inode, filp);
1197 if (ret < 0) {
1198 trace_array_put(tr);
1199 kfree(dir);
1200 return ret;
1201 }
1202
1203 filp->private_data = dir;
1204
1205 return 0;
1206 }
1207
1208 static int subsystem_release(struct inode *inode, struct file *file)
1209 {
1210 struct ftrace_subsystem_dir *dir = file->private_data;
1211
1212 trace_array_put(dir->tr);
1213
1214 /*
1215 * If dir->subsystem is NULL, then this is a temporary
1216 * descriptor that was made for a trace_array to enable
1217 * all subsystems.
1218 */
1219 if (dir->subsystem)
1220 put_system(dir);
1221 else
1222 kfree(dir);
1223
1224 return 0;
1225 }
1226
1227 static ssize_t
1228 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1229 loff_t *ppos)
1230 {
1231 struct ftrace_subsystem_dir *dir = filp->private_data;
1232 struct event_subsystem *system = dir->subsystem;
1233 struct trace_seq *s;
1234 int r;
1235
1236 if (*ppos)
1237 return 0;
1238
1239 s = kmalloc(sizeof(*s), GFP_KERNEL);
1240 if (!s)
1241 return -ENOMEM;
1242
1243 trace_seq_init(s);
1244
1245 print_subsystem_event_filter(system, s);
1246 r = simple_read_from_buffer(ubuf, cnt, ppos,
1247 s->buffer, trace_seq_used(s));
1248
1249 kfree(s);
1250
1251 return r;
1252 }
1253
1254 static ssize_t
1255 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1256 loff_t *ppos)
1257 {
1258 struct ftrace_subsystem_dir *dir = filp->private_data;
1259 char *buf;
1260 int err;
1261
1262 if (cnt >= PAGE_SIZE)
1263 return -EINVAL;
1264
1265 buf = (char *)__get_free_page(GFP_TEMPORARY);
1266 if (!buf)
1267 return -ENOMEM;
1268
1269 if (copy_from_user(buf, ubuf, cnt)) {
1270 free_page((unsigned long) buf);
1271 return -EFAULT;
1272 }
1273 buf[cnt] = '\0';
1274
1275 err = apply_subsystem_event_filter(dir, buf);
1276 free_page((unsigned long) buf);
1277 if (err < 0)
1278 return err;
1279
1280 *ppos += cnt;
1281
1282 return cnt;
1283 }
1284
1285 static ssize_t
1286 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1287 {
1288 int (*func)(struct trace_seq *s) = filp->private_data;
1289 struct trace_seq *s;
1290 int r;
1291
1292 if (*ppos)
1293 return 0;
1294
1295 s = kmalloc(sizeof(*s), GFP_KERNEL);
1296 if (!s)
1297 return -ENOMEM;
1298
1299 trace_seq_init(s);
1300
1301 func(s);
1302 r = simple_read_from_buffer(ubuf, cnt, ppos,
1303 s->buffer, trace_seq_used(s));
1304
1305 kfree(s);
1306
1307 return r;
1308 }
1309
1310 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1311 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1312 static int ftrace_event_release(struct inode *inode, struct file *file);
1313
1314 static const struct seq_operations show_event_seq_ops = {
1315 .start = t_start,
1316 .next = t_next,
1317 .show = t_show,
1318 .stop = t_stop,
1319 };
1320
1321 static const struct seq_operations show_set_event_seq_ops = {
1322 .start = s_start,
1323 .next = s_next,
1324 .show = t_show,
1325 .stop = t_stop,
1326 };
1327
1328 static const struct file_operations ftrace_avail_fops = {
1329 .open = ftrace_event_avail_open,
1330 .read = seq_read,
1331 .llseek = seq_lseek,
1332 .release = seq_release,
1333 };
1334
1335 static const struct file_operations ftrace_set_event_fops = {
1336 .open = ftrace_event_set_open,
1337 .read = seq_read,
1338 .write = ftrace_event_write,
1339 .llseek = seq_lseek,
1340 .release = ftrace_event_release,
1341 };
1342
1343 static const struct file_operations ftrace_enable_fops = {
1344 .open = tracing_open_generic,
1345 .read = event_enable_read,
1346 .write = event_enable_write,
1347 .llseek = default_llseek,
1348 };
1349
1350 static const struct file_operations ftrace_event_format_fops = {
1351 .open = trace_format_open,
1352 .read = seq_read,
1353 .llseek = seq_lseek,
1354 .release = seq_release,
1355 };
1356
1357 static const struct file_operations ftrace_event_id_fops = {
1358 .read = event_id_read,
1359 .llseek = default_llseek,
1360 };
1361
1362 static const struct file_operations ftrace_event_filter_fops = {
1363 .open = tracing_open_generic,
1364 .read = event_filter_read,
1365 .write = event_filter_write,
1366 .llseek = default_llseek,
1367 };
1368
1369 static const struct file_operations ftrace_subsystem_filter_fops = {
1370 .open = subsystem_open,
1371 .read = subsystem_filter_read,
1372 .write = subsystem_filter_write,
1373 .llseek = default_llseek,
1374 .release = subsystem_release,
1375 };
1376
1377 static const struct file_operations ftrace_system_enable_fops = {
1378 .open = subsystem_open,
1379 .read = system_enable_read,
1380 .write = system_enable_write,
1381 .llseek = default_llseek,
1382 .release = subsystem_release,
1383 };
1384
1385 static const struct file_operations ftrace_tr_enable_fops = {
1386 .open = system_tr_open,
1387 .read = system_enable_read,
1388 .write = system_enable_write,
1389 .llseek = default_llseek,
1390 .release = subsystem_release,
1391 };
1392
1393 static const struct file_operations ftrace_show_header_fops = {
1394 .open = tracing_open_generic,
1395 .read = show_header,
1396 .llseek = default_llseek,
1397 };
1398
1399 static int
1400 ftrace_event_open(struct inode *inode, struct file *file,
1401 const struct seq_operations *seq_ops)
1402 {
1403 struct seq_file *m;
1404 int ret;
1405
1406 ret = seq_open(file, seq_ops);
1407 if (ret < 0)
1408 return ret;
1409 m = file->private_data;
1410 /* copy tr over to seq ops */
1411 m->private = inode->i_private;
1412
1413 return ret;
1414 }
1415
1416 static int ftrace_event_release(struct inode *inode, struct file *file)
1417 {
1418 struct trace_array *tr = inode->i_private;
1419
1420 trace_array_put(tr);
1421
1422 return seq_release(inode, file);
1423 }
1424
1425 static int
1426 ftrace_event_avail_open(struct inode *inode, struct file *file)
1427 {
1428 const struct seq_operations *seq_ops = &show_event_seq_ops;
1429
1430 return ftrace_event_open(inode, file, seq_ops);
1431 }
1432
1433 static int
1434 ftrace_event_set_open(struct inode *inode, struct file *file)
1435 {
1436 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1437 struct trace_array *tr = inode->i_private;
1438 int ret;
1439
1440 if (trace_array_get(tr) < 0)
1441 return -ENODEV;
1442
1443 if ((file->f_mode & FMODE_WRITE) &&
1444 (file->f_flags & O_TRUNC))
1445 ftrace_clear_events(tr);
1446
1447 ret = ftrace_event_open(inode, file, seq_ops);
1448 if (ret < 0)
1449 trace_array_put(tr);
1450 return ret;
1451 }
1452
1453 static struct event_subsystem *
1454 create_new_subsystem(const char *name)
1455 {
1456 struct event_subsystem *system;
1457
1458 /* need to create new entry */
1459 system = kmalloc(sizeof(*system), GFP_KERNEL);
1460 if (!system)
1461 return NULL;
1462
1463 system->ref_count = 1;
1464
1465 /* Only allocate if dynamic (kprobes and modules) */
1466 if (!core_kernel_data((unsigned long)name)) {
1467 system->ref_count |= SYSTEM_FL_FREE_NAME;
1468 system->name = kstrdup(name, GFP_KERNEL);
1469 if (!system->name)
1470 goto out_free;
1471 } else
1472 system->name = name;
1473
1474 system->filter = NULL;
1475
1476 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1477 if (!system->filter)
1478 goto out_free;
1479
1480 list_add(&system->list, &event_subsystems);
1481
1482 return system;
1483
1484 out_free:
1485 if (system->ref_count & SYSTEM_FL_FREE_NAME)
1486 kfree(system->name);
1487 kfree(system);
1488 return NULL;
1489 }
1490
1491 static struct dentry *
1492 event_subsystem_dir(struct trace_array *tr, const char *name,
1493 struct ftrace_event_file *file, struct dentry *parent)
1494 {
1495 struct ftrace_subsystem_dir *dir;
1496 struct event_subsystem *system;
1497 struct dentry *entry;
1498
1499 /* First see if we did not already create this dir */
1500 list_for_each_entry(dir, &tr->systems, list) {
1501 system = dir->subsystem;
1502 if (strcmp(system->name, name) == 0) {
1503 dir->nr_events++;
1504 file->system = dir;
1505 return dir->entry;
1506 }
1507 }
1508
1509 /* Now see if the system itself exists. */
1510 list_for_each_entry(system, &event_subsystems, list) {
1511 if (strcmp(system->name, name) == 0)
1512 break;
1513 }
1514 /* Reset system variable when not found */
1515 if (&system->list == &event_subsystems)
1516 system = NULL;
1517
1518 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1519 if (!dir)
1520 goto out_fail;
1521
1522 if (!system) {
1523 system = create_new_subsystem(name);
1524 if (!system)
1525 goto out_free;
1526 } else
1527 __get_system(system);
1528
1529 dir->entry = debugfs_create_dir(name, parent);
1530 if (!dir->entry) {
1531 pr_warn("Failed to create system directory %s\n", name);
1532 __put_system(system);
1533 goto out_free;
1534 }
1535
1536 dir->tr = tr;
1537 dir->ref_count = 1;
1538 dir->nr_events = 1;
1539 dir->subsystem = system;
1540 file->system = dir;
1541
1542 entry = debugfs_create_file("filter", 0644, dir->entry, dir,
1543 &ftrace_subsystem_filter_fops);
1544 if (!entry) {
1545 kfree(system->filter);
1546 system->filter = NULL;
1547 pr_warn("Could not create debugfs '%s/filter' entry\n", name);
1548 }
1549
1550 trace_create_file("enable", 0644, dir->entry, dir,
1551 &ftrace_system_enable_fops);
1552
1553 list_add(&dir->list, &tr->systems);
1554
1555 return dir->entry;
1556
1557 out_free:
1558 kfree(dir);
1559 out_fail:
1560 /* Only print this message if failed on memory allocation */
1561 if (!dir || !system)
1562 pr_warn("No memory to create event subsystem %s\n", name);
1563 return NULL;
1564 }
1565
1566 static int
1567 event_create_dir(struct dentry *parent, struct ftrace_event_file *file)
1568 {
1569 struct ftrace_event_call *call = file->event_call;
1570 struct trace_array *tr = file->tr;
1571 struct list_head *head;
1572 struct dentry *d_events;
1573 const char *name;
1574 int ret;
1575
1576 /*
1577 * If the trace point header did not define TRACE_SYSTEM
1578 * then the system would be called "TRACE_SYSTEM".
1579 */
1580 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1581 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1582 if (!d_events)
1583 return -ENOMEM;
1584 } else
1585 d_events = parent;
1586
1587 name = ftrace_event_name(call);
1588 file->dir = debugfs_create_dir(name, d_events);
1589 if (!file->dir) {
1590 pr_warn("Could not create debugfs '%s' directory\n", name);
1591 return -1;
1592 }
1593
1594 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1595 trace_create_file("enable", 0644, file->dir, file,
1596 &ftrace_enable_fops);
1597
1598 #ifdef CONFIG_PERF_EVENTS
1599 if (call->event.type && call->class->reg)
1600 trace_create_file("id", 0444, file->dir,
1601 (void *)(long)call->event.type,
1602 &ftrace_event_id_fops);
1603 #endif
1604
1605 /*
1606 * Other events may have the same class. Only update
1607 * the fields if they are not already defined.
1608 */
1609 head = trace_get_fields(call);
1610 if (list_empty(head)) {
1611 ret = call->class->define_fields(call);
1612 if (ret < 0) {
1613 pr_warn("Could not initialize trace point events/%s\n",
1614 name);
1615 return -1;
1616 }
1617 }
1618 trace_create_file("filter", 0644, file->dir, file,
1619 &ftrace_event_filter_fops);
1620
1621 trace_create_file("trigger", 0644, file->dir, file,
1622 &event_trigger_fops);
1623
1624 trace_create_file("format", 0444, file->dir, call,
1625 &ftrace_event_format_fops);
1626
1627 return 0;
1628 }
1629
1630 static void remove_event_from_tracers(struct ftrace_event_call *call)
1631 {
1632 struct ftrace_event_file *file;
1633 struct trace_array *tr;
1634
1635 do_for_each_event_file_safe(tr, file) {
1636 if (file->event_call != call)
1637 continue;
1638
1639 remove_event_file_dir(file);
1640 /*
1641 * The do_for_each_event_file_safe() is
1642 * a double loop. After finding the call for this
1643 * trace_array, we use break to jump to the next
1644 * trace_array.
1645 */
1646 break;
1647 } while_for_each_event_file();
1648 }
1649
1650 static void event_remove(struct ftrace_event_call *call)
1651 {
1652 struct trace_array *tr;
1653 struct ftrace_event_file *file;
1654
1655 do_for_each_event_file(tr, file) {
1656 if (file->event_call != call)
1657 continue;
1658 ftrace_event_enable_disable(file, 0);
1659 /*
1660 * The do_for_each_event_file() is
1661 * a double loop. After finding the call for this
1662 * trace_array, we use break to jump to the next
1663 * trace_array.
1664 */
1665 break;
1666 } while_for_each_event_file();
1667
1668 if (call->event.funcs)
1669 __unregister_ftrace_event(&call->event);
1670 remove_event_from_tracers(call);
1671 list_del(&call->list);
1672 }
1673
1674 static int event_init(struct ftrace_event_call *call)
1675 {
1676 int ret = 0;
1677 const char *name;
1678
1679 name = ftrace_event_name(call);
1680 if (WARN_ON(!name))
1681 return -EINVAL;
1682
1683 if (call->class->raw_init) {
1684 ret = call->class->raw_init(call);
1685 if (ret < 0 && ret != -ENOSYS)
1686 pr_warn("Could not initialize trace events/%s\n", name);
1687 }
1688
1689 return ret;
1690 }
1691
1692 static int
1693 __register_event(struct ftrace_event_call *call, struct module *mod)
1694 {
1695 int ret;
1696
1697 ret = event_init(call);
1698 if (ret < 0)
1699 return ret;
1700
1701 list_add(&call->list, &ftrace_events);
1702 call->mod = mod;
1703
1704 return 0;
1705 }
1706
1707 static struct ftrace_event_file *
1708 trace_create_new_event(struct ftrace_event_call *call,
1709 struct trace_array *tr)
1710 {
1711 struct ftrace_event_file *file;
1712
1713 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
1714 if (!file)
1715 return NULL;
1716
1717 file->event_call = call;
1718 file->tr = tr;
1719 atomic_set(&file->sm_ref, 0);
1720 atomic_set(&file->tm_ref, 0);
1721 INIT_LIST_HEAD(&file->triggers);
1722 list_add(&file->list, &tr->events);
1723
1724 return file;
1725 }
1726
1727 /* Add an event to a trace directory */
1728 static int
1729 __trace_add_new_event(struct ftrace_event_call *call, struct trace_array *tr)
1730 {
1731 struct ftrace_event_file *file;
1732
1733 file = trace_create_new_event(call, tr);
1734 if (!file)
1735 return -ENOMEM;
1736
1737 return event_create_dir(tr->event_dir, file);
1738 }
1739
1740 /*
1741 * Just create a decriptor for early init. A descriptor is required
1742 * for enabling events at boot. We want to enable events before
1743 * the filesystem is initialized.
1744 */
1745 static __init int
1746 __trace_early_add_new_event(struct ftrace_event_call *call,
1747 struct trace_array *tr)
1748 {
1749 struct ftrace_event_file *file;
1750
1751 file = trace_create_new_event(call, tr);
1752 if (!file)
1753 return -ENOMEM;
1754
1755 return 0;
1756 }
1757
1758 struct ftrace_module_file_ops;
1759 static void __add_event_to_tracers(struct ftrace_event_call *call);
1760
1761 /* Add an additional event_call dynamically */
1762 int trace_add_event_call(struct ftrace_event_call *call)
1763 {
1764 int ret;
1765 mutex_lock(&trace_types_lock);
1766 mutex_lock(&event_mutex);
1767
1768 ret = __register_event(call, NULL);
1769 if (ret >= 0)
1770 __add_event_to_tracers(call);
1771
1772 mutex_unlock(&event_mutex);
1773 mutex_unlock(&trace_types_lock);
1774 return ret;
1775 }
1776
1777 /*
1778 * Must be called under locking of trace_types_lock, event_mutex and
1779 * trace_event_sem.
1780 */
1781 static void __trace_remove_event_call(struct ftrace_event_call *call)
1782 {
1783 event_remove(call);
1784 trace_destroy_fields(call);
1785 free_event_filter(call->filter);
1786 call->filter = NULL;
1787 }
1788
1789 static int probe_remove_event_call(struct ftrace_event_call *call)
1790 {
1791 struct trace_array *tr;
1792 struct ftrace_event_file *file;
1793
1794 #ifdef CONFIG_PERF_EVENTS
1795 if (call->perf_refcount)
1796 return -EBUSY;
1797 #endif
1798 do_for_each_event_file(tr, file) {
1799 if (file->event_call != call)
1800 continue;
1801 /*
1802 * We can't rely on ftrace_event_enable_disable(enable => 0)
1803 * we are going to do, FTRACE_EVENT_FL_SOFT_MODE can suppress
1804 * TRACE_REG_UNREGISTER.
1805 */
1806 if (file->flags & FTRACE_EVENT_FL_ENABLED)
1807 return -EBUSY;
1808 /*
1809 * The do_for_each_event_file_safe() is
1810 * a double loop. After finding the call for this
1811 * trace_array, we use break to jump to the next
1812 * trace_array.
1813 */
1814 break;
1815 } while_for_each_event_file();
1816
1817 __trace_remove_event_call(call);
1818
1819 return 0;
1820 }
1821
1822 /* Remove an event_call */
1823 int trace_remove_event_call(struct ftrace_event_call *call)
1824 {
1825 int ret;
1826
1827 mutex_lock(&trace_types_lock);
1828 mutex_lock(&event_mutex);
1829 down_write(&trace_event_sem);
1830 ret = probe_remove_event_call(call);
1831 up_write(&trace_event_sem);
1832 mutex_unlock(&event_mutex);
1833 mutex_unlock(&trace_types_lock);
1834
1835 return ret;
1836 }
1837
1838 #define for_each_event(event, start, end) \
1839 for (event = start; \
1840 (unsigned long)event < (unsigned long)end; \
1841 event++)
1842
1843 #ifdef CONFIG_MODULES
1844
1845 static void trace_module_add_events(struct module *mod)
1846 {
1847 struct ftrace_event_call **call, **start, **end;
1848
1849 if (!mod->num_trace_events)
1850 return;
1851
1852 /* Don't add infrastructure for mods without tracepoints */
1853 if (trace_module_has_bad_taint(mod)) {
1854 pr_err("%s: module has bad taint, not creating trace events\n",
1855 mod->name);
1856 return;
1857 }
1858
1859 start = mod->trace_events;
1860 end = mod->trace_events + mod->num_trace_events;
1861
1862 for_each_event(call, start, end) {
1863 __register_event(*call, mod);
1864 __add_event_to_tracers(*call);
1865 }
1866 }
1867
1868 static void trace_module_remove_events(struct module *mod)
1869 {
1870 struct ftrace_event_call *call, *p;
1871 bool clear_trace = false;
1872
1873 down_write(&trace_event_sem);
1874 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1875 if (call->mod == mod) {
1876 if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
1877 clear_trace = true;
1878 __trace_remove_event_call(call);
1879 }
1880 }
1881 up_write(&trace_event_sem);
1882
1883 /*
1884 * It is safest to reset the ring buffer if the module being unloaded
1885 * registered any events that were used. The only worry is if
1886 * a new module gets loaded, and takes on the same id as the events
1887 * of this module. When printing out the buffer, traced events left
1888 * over from this module may be passed to the new module events and
1889 * unexpected results may occur.
1890 */
1891 if (clear_trace)
1892 tracing_reset_all_online_cpus();
1893 }
1894
1895 static int trace_module_notify(struct notifier_block *self,
1896 unsigned long val, void *data)
1897 {
1898 struct module *mod = data;
1899
1900 mutex_lock(&trace_types_lock);
1901 mutex_lock(&event_mutex);
1902 switch (val) {
1903 case MODULE_STATE_COMING:
1904 trace_module_add_events(mod);
1905 break;
1906 case MODULE_STATE_GOING:
1907 trace_module_remove_events(mod);
1908 break;
1909 }
1910 mutex_unlock(&event_mutex);
1911 mutex_unlock(&trace_types_lock);
1912
1913 return 0;
1914 }
1915
1916 static struct notifier_block trace_module_nb = {
1917 .notifier_call = trace_module_notify,
1918 .priority = 0,
1919 };
1920 #endif /* CONFIG_MODULES */
1921
1922 /* Create a new event directory structure for a trace directory. */
1923 static void
1924 __trace_add_event_dirs(struct trace_array *tr)
1925 {
1926 struct ftrace_event_call *call;
1927 int ret;
1928
1929 list_for_each_entry(call, &ftrace_events, list) {
1930 ret = __trace_add_new_event(call, tr);
1931 if (ret < 0)
1932 pr_warn("Could not create directory for event %s\n",
1933 ftrace_event_name(call));
1934 }
1935 }
1936
1937 struct ftrace_event_file *
1938 find_event_file(struct trace_array *tr, const char *system, const char *event)
1939 {
1940 struct ftrace_event_file *file;
1941 struct ftrace_event_call *call;
1942 const char *name;
1943
1944 list_for_each_entry(file, &tr->events, list) {
1945
1946 call = file->event_call;
1947 name = ftrace_event_name(call);
1948
1949 if (!name || !call->class || !call->class->reg)
1950 continue;
1951
1952 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1953 continue;
1954
1955 if (strcmp(event, name) == 0 &&
1956 strcmp(system, call->class->system) == 0)
1957 return file;
1958 }
1959 return NULL;
1960 }
1961
1962 #ifdef CONFIG_DYNAMIC_FTRACE
1963
1964 /* Avoid typos */
1965 #define ENABLE_EVENT_STR "enable_event"
1966 #define DISABLE_EVENT_STR "disable_event"
1967
1968 struct event_probe_data {
1969 struct ftrace_event_file *file;
1970 unsigned long count;
1971 int ref;
1972 bool enable;
1973 };
1974
1975 static void
1976 event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1977 {
1978 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1979 struct event_probe_data *data = *pdata;
1980
1981 if (!data)
1982 return;
1983
1984 if (data->enable)
1985 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1986 else
1987 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1988 }
1989
1990 static void
1991 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1992 {
1993 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1994 struct event_probe_data *data = *pdata;
1995
1996 if (!data)
1997 return;
1998
1999 if (!data->count)
2000 return;
2001
2002 /* Skip if the event is in a state we want to switch to */
2003 if (data->enable == !(data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
2004 return;
2005
2006 if (data->count != -1)
2007 (data->count)--;
2008
2009 event_enable_probe(ip, parent_ip, _data);
2010 }
2011
2012 static int
2013 event_enable_print(struct seq_file *m, unsigned long ip,
2014 struct ftrace_probe_ops *ops, void *_data)
2015 {
2016 struct event_probe_data *data = _data;
2017
2018 seq_printf(m, "%ps:", (void *)ip);
2019
2020 seq_printf(m, "%s:%s:%s",
2021 data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
2022 data->file->event_call->class->system,
2023 ftrace_event_name(data->file->event_call));
2024
2025 if (data->count == -1)
2026 seq_puts(m, ":unlimited\n");
2027 else
2028 seq_printf(m, ":count=%ld\n", data->count);
2029
2030 return 0;
2031 }
2032
2033 static int
2034 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
2035 void **_data)
2036 {
2037 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2038 struct event_probe_data *data = *pdata;
2039
2040 data->ref++;
2041 return 0;
2042 }
2043
2044 static void
2045 event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
2046 void **_data)
2047 {
2048 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2049 struct event_probe_data *data = *pdata;
2050
2051 if (WARN_ON_ONCE(data->ref <= 0))
2052 return;
2053
2054 data->ref--;
2055 if (!data->ref) {
2056 /* Remove the SOFT_MODE flag */
2057 __ftrace_event_enable_disable(data->file, 0, 1);
2058 module_put(data->file->event_call->mod);
2059 kfree(data);
2060 }
2061 *pdata = NULL;
2062 }
2063
2064 static struct ftrace_probe_ops event_enable_probe_ops = {
2065 .func = event_enable_probe,
2066 .print = event_enable_print,
2067 .init = event_enable_init,
2068 .free = event_enable_free,
2069 };
2070
2071 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2072 .func = event_enable_count_probe,
2073 .print = event_enable_print,
2074 .init = event_enable_init,
2075 .free = event_enable_free,
2076 };
2077
2078 static struct ftrace_probe_ops event_disable_probe_ops = {
2079 .func = event_enable_probe,
2080 .print = event_enable_print,
2081 .init = event_enable_init,
2082 .free = event_enable_free,
2083 };
2084
2085 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2086 .func = event_enable_count_probe,
2087 .print = event_enable_print,
2088 .init = event_enable_init,
2089 .free = event_enable_free,
2090 };
2091
2092 static int
2093 event_enable_func(struct ftrace_hash *hash,
2094 char *glob, char *cmd, char *param, int enabled)
2095 {
2096 struct trace_array *tr = top_trace_array();
2097 struct ftrace_event_file *file;
2098 struct ftrace_probe_ops *ops;
2099 struct event_probe_data *data;
2100 const char *system;
2101 const char *event;
2102 char *number;
2103 bool enable;
2104 int ret;
2105
2106 if (!tr)
2107 return -ENODEV;
2108
2109 /* hash funcs only work with set_ftrace_filter */
2110 if (!enabled || !param)
2111 return -EINVAL;
2112
2113 system = strsep(&param, ":");
2114 if (!param)
2115 return -EINVAL;
2116
2117 event = strsep(&param, ":");
2118
2119 mutex_lock(&event_mutex);
2120
2121 ret = -EINVAL;
2122 file = find_event_file(tr, system, event);
2123 if (!file)
2124 goto out;
2125
2126 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2127
2128 if (enable)
2129 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2130 else
2131 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2132
2133 if (glob[0] == '!') {
2134 unregister_ftrace_function_probe_func(glob+1, ops);
2135 ret = 0;
2136 goto out;
2137 }
2138
2139 ret = -ENOMEM;
2140 data = kzalloc(sizeof(*data), GFP_KERNEL);
2141 if (!data)
2142 goto out;
2143
2144 data->enable = enable;
2145 data->count = -1;
2146 data->file = file;
2147
2148 if (!param)
2149 goto out_reg;
2150
2151 number = strsep(&param, ":");
2152
2153 ret = -EINVAL;
2154 if (!strlen(number))
2155 goto out_free;
2156
2157 /*
2158 * We use the callback data field (which is a pointer)
2159 * as our counter.
2160 */
2161 ret = kstrtoul(number, 0, &data->count);
2162 if (ret)
2163 goto out_free;
2164
2165 out_reg:
2166 /* Don't let event modules unload while probe registered */
2167 ret = try_module_get(file->event_call->mod);
2168 if (!ret) {
2169 ret = -EBUSY;
2170 goto out_free;
2171 }
2172
2173 ret = __ftrace_event_enable_disable(file, 1, 1);
2174 if (ret < 0)
2175 goto out_put;
2176 ret = register_ftrace_function_probe(glob, ops, data);
2177 /*
2178 * The above returns on success the # of functions enabled,
2179 * but if it didn't find any functions it returns zero.
2180 * Consider no functions a failure too.
2181 */
2182 if (!ret) {
2183 ret = -ENOENT;
2184 goto out_disable;
2185 } else if (ret < 0)
2186 goto out_disable;
2187 /* Just return zero, not the number of enabled functions */
2188 ret = 0;
2189 out:
2190 mutex_unlock(&event_mutex);
2191 return ret;
2192
2193 out_disable:
2194 __ftrace_event_enable_disable(file, 0, 1);
2195 out_put:
2196 module_put(file->event_call->mod);
2197 out_free:
2198 kfree(data);
2199 goto out;
2200 }
2201
2202 static struct ftrace_func_command event_enable_cmd = {
2203 .name = ENABLE_EVENT_STR,
2204 .func = event_enable_func,
2205 };
2206
2207 static struct ftrace_func_command event_disable_cmd = {
2208 .name = DISABLE_EVENT_STR,
2209 .func = event_enable_func,
2210 };
2211
2212 static __init int register_event_cmds(void)
2213 {
2214 int ret;
2215
2216 ret = register_ftrace_command(&event_enable_cmd);
2217 if (WARN_ON(ret < 0))
2218 return ret;
2219 ret = register_ftrace_command(&event_disable_cmd);
2220 if (WARN_ON(ret < 0))
2221 unregister_ftrace_command(&event_enable_cmd);
2222 return ret;
2223 }
2224 #else
2225 static inline int register_event_cmds(void) { return 0; }
2226 #endif /* CONFIG_DYNAMIC_FTRACE */
2227
2228 /*
2229 * The top level array has already had its ftrace_event_file
2230 * descriptors created in order to allow for early events to
2231 * be recorded. This function is called after the debugfs has been
2232 * initialized, and we now have to create the files associated
2233 * to the events.
2234 */
2235 static __init void
2236 __trace_early_add_event_dirs(struct trace_array *tr)
2237 {
2238 struct ftrace_event_file *file;
2239 int ret;
2240
2241
2242 list_for_each_entry(file, &tr->events, list) {
2243 ret = event_create_dir(tr->event_dir, file);
2244 if (ret < 0)
2245 pr_warn("Could not create directory for event %s\n",
2246 ftrace_event_name(file->event_call));
2247 }
2248 }
2249
2250 /*
2251 * For early boot up, the top trace array requires to have
2252 * a list of events that can be enabled. This must be done before
2253 * the filesystem is set up in order to allow events to be traced
2254 * early.
2255 */
2256 static __init void
2257 __trace_early_add_events(struct trace_array *tr)
2258 {
2259 struct ftrace_event_call *call;
2260 int ret;
2261
2262 list_for_each_entry(call, &ftrace_events, list) {
2263 /* Early boot up should not have any modules loaded */
2264 if (WARN_ON_ONCE(call->mod))
2265 continue;
2266
2267 ret = __trace_early_add_new_event(call, tr);
2268 if (ret < 0)
2269 pr_warn("Could not create early event %s\n",
2270 ftrace_event_name(call));
2271 }
2272 }
2273
2274 /* Remove the event directory structure for a trace directory. */
2275 static void
2276 __trace_remove_event_dirs(struct trace_array *tr)
2277 {
2278 struct ftrace_event_file *file, *next;
2279
2280 list_for_each_entry_safe(file, next, &tr->events, list)
2281 remove_event_file_dir(file);
2282 }
2283
2284 static void __add_event_to_tracers(struct ftrace_event_call *call)
2285 {
2286 struct trace_array *tr;
2287
2288 list_for_each_entry(tr, &ftrace_trace_arrays, list)
2289 __trace_add_new_event(call, tr);
2290 }
2291
2292 extern struct ftrace_event_call *__start_ftrace_events[];
2293 extern struct ftrace_event_call *__stop_ftrace_events[];
2294
2295 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2296
2297 static __init int setup_trace_event(char *str)
2298 {
2299 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2300 ring_buffer_expanded = true;
2301 tracing_selftest_disabled = true;
2302
2303 return 1;
2304 }
2305 __setup("trace_event=", setup_trace_event);
2306
2307 /* Expects to have event_mutex held when called */
2308 static int
2309 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2310 {
2311 struct dentry *d_events;
2312 struct dentry *entry;
2313
2314 entry = debugfs_create_file("set_event", 0644, parent,
2315 tr, &ftrace_set_event_fops);
2316 if (!entry) {
2317 pr_warn("Could not create debugfs 'set_event' entry\n");
2318 return -ENOMEM;
2319 }
2320
2321 d_events = debugfs_create_dir("events", parent);
2322 if (!d_events) {
2323 pr_warn("Could not create debugfs 'events' directory\n");
2324 return -ENOMEM;
2325 }
2326
2327 /* ring buffer internal formats */
2328 trace_create_file("header_page", 0444, d_events,
2329 ring_buffer_print_page_header,
2330 &ftrace_show_header_fops);
2331
2332 trace_create_file("header_event", 0444, d_events,
2333 ring_buffer_print_entry_header,
2334 &ftrace_show_header_fops);
2335
2336 trace_create_file("enable", 0644, d_events,
2337 tr, &ftrace_tr_enable_fops);
2338
2339 tr->event_dir = d_events;
2340
2341 return 0;
2342 }
2343
2344 /**
2345 * event_trace_add_tracer - add a instance of a trace_array to events
2346 * @parent: The parent dentry to place the files/directories for events in
2347 * @tr: The trace array associated with these events
2348 *
2349 * When a new instance is created, it needs to set up its events
2350 * directory, as well as other files associated with events. It also
2351 * creates the event hierachry in the @parent/events directory.
2352 *
2353 * Returns 0 on success.
2354 */
2355 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2356 {
2357 int ret;
2358
2359 mutex_lock(&event_mutex);
2360
2361 ret = create_event_toplevel_files(parent, tr);
2362 if (ret)
2363 goto out_unlock;
2364
2365 down_write(&trace_event_sem);
2366 __trace_add_event_dirs(tr);
2367 up_write(&trace_event_sem);
2368
2369 out_unlock:
2370 mutex_unlock(&event_mutex);
2371
2372 return ret;
2373 }
2374
2375 /*
2376 * The top trace array already had its file descriptors created.
2377 * Now the files themselves need to be created.
2378 */
2379 static __init int
2380 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2381 {
2382 int ret;
2383
2384 mutex_lock(&event_mutex);
2385
2386 ret = create_event_toplevel_files(parent, tr);
2387 if (ret)
2388 goto out_unlock;
2389
2390 down_write(&trace_event_sem);
2391 __trace_early_add_event_dirs(tr);
2392 up_write(&trace_event_sem);
2393
2394 out_unlock:
2395 mutex_unlock(&event_mutex);
2396
2397 return ret;
2398 }
2399
2400 int event_trace_del_tracer(struct trace_array *tr)
2401 {
2402 mutex_lock(&event_mutex);
2403
2404 /* Disable any event triggers and associated soft-disabled events */
2405 clear_event_triggers(tr);
2406
2407 /* Disable any running events */
2408 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
2409
2410 /* Access to events are within rcu_read_lock_sched() */
2411 synchronize_sched();
2412
2413 down_write(&trace_event_sem);
2414 __trace_remove_event_dirs(tr);
2415 debugfs_remove_recursive(tr->event_dir);
2416 up_write(&trace_event_sem);
2417
2418 tr->event_dir = NULL;
2419
2420 mutex_unlock(&event_mutex);
2421
2422 return 0;
2423 }
2424
2425 static __init int event_trace_memsetup(void)
2426 {
2427 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
2428 file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC);
2429 return 0;
2430 }
2431
2432 static __init int event_trace_enable(void)
2433 {
2434 struct trace_array *tr = top_trace_array();
2435 struct ftrace_event_call **iter, *call;
2436 char *buf = bootup_event_buf;
2437 char *token;
2438 int ret;
2439
2440 if (!tr)
2441 return -ENODEV;
2442
2443 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
2444
2445 call = *iter;
2446 ret = event_init(call);
2447 if (!ret)
2448 list_add(&call->list, &ftrace_events);
2449 }
2450
2451 /*
2452 * We need the top trace array to have a working set of trace
2453 * points at early init, before the debug files and directories
2454 * are created. Create the file entries now, and attach them
2455 * to the actual file dentries later.
2456 */
2457 __trace_early_add_events(tr);
2458
2459 while (true) {
2460 token = strsep(&buf, ",");
2461
2462 if (!token)
2463 break;
2464 if (!*token)
2465 continue;
2466
2467 ret = ftrace_set_clr_event(tr, token, 1);
2468 if (ret)
2469 pr_warn("Failed to enable trace event: %s\n", token);
2470 }
2471
2472 trace_printk_start_comm();
2473
2474 register_event_cmds();
2475
2476 register_trigger_cmds();
2477
2478 return 0;
2479 }
2480
2481 static __init int event_trace_init(void)
2482 {
2483 struct trace_array *tr;
2484 struct dentry *d_tracer;
2485 struct dentry *entry;
2486 int ret;
2487
2488 tr = top_trace_array();
2489 if (!tr)
2490 return -ENODEV;
2491
2492 d_tracer = tracing_init_dentry();
2493 if (!d_tracer)
2494 return 0;
2495
2496 entry = debugfs_create_file("available_events", 0444, d_tracer,
2497 tr, &ftrace_avail_fops);
2498 if (!entry)
2499 pr_warn("Could not create debugfs 'available_events' entry\n");
2500
2501 if (trace_define_common_fields())
2502 pr_warn("tracing: Failed to allocate common fields");
2503
2504 ret = early_event_add_tracer(d_tracer, tr);
2505 if (ret)
2506 return ret;
2507
2508 #ifdef CONFIG_MODULES
2509 ret = register_module_notifier(&trace_module_nb);
2510 if (ret)
2511 pr_warn("Failed to register trace events module notifier\n");
2512 #endif
2513 return 0;
2514 }
2515
2516 void __init trace_event_init(void)
2517 {
2518 event_trace_memsetup();
2519 init_ftrace_syscalls();
2520 event_trace_enable();
2521 }
2522
2523 fs_initcall(event_trace_init);
2524
2525 #ifdef CONFIG_FTRACE_STARTUP_TEST
2526
2527 static DEFINE_SPINLOCK(test_spinlock);
2528 static DEFINE_SPINLOCK(test_spinlock_irq);
2529 static DEFINE_MUTEX(test_mutex);
2530
2531 static __init void test_work(struct work_struct *dummy)
2532 {
2533 spin_lock(&test_spinlock);
2534 spin_lock_irq(&test_spinlock_irq);
2535 udelay(1);
2536 spin_unlock_irq(&test_spinlock_irq);
2537 spin_unlock(&test_spinlock);
2538
2539 mutex_lock(&test_mutex);
2540 msleep(1);
2541 mutex_unlock(&test_mutex);
2542 }
2543
2544 static __init int event_test_thread(void *unused)
2545 {
2546 void *test_malloc;
2547
2548 test_malloc = kmalloc(1234, GFP_KERNEL);
2549 if (!test_malloc)
2550 pr_info("failed to kmalloc\n");
2551
2552 schedule_on_each_cpu(test_work);
2553
2554 kfree(test_malloc);
2555
2556 set_current_state(TASK_INTERRUPTIBLE);
2557 while (!kthread_should_stop()) {
2558 schedule();
2559 set_current_state(TASK_INTERRUPTIBLE);
2560 }
2561 __set_current_state(TASK_RUNNING);
2562
2563 return 0;
2564 }
2565
2566 /*
2567 * Do various things that may trigger events.
2568 */
2569 static __init void event_test_stuff(void)
2570 {
2571 struct task_struct *test_thread;
2572
2573 test_thread = kthread_run(event_test_thread, NULL, "test-events");
2574 msleep(1);
2575 kthread_stop(test_thread);
2576 }
2577
2578 /*
2579 * For every trace event defined, we will test each trace point separately,
2580 * and then by groups, and finally all trace points.
2581 */
2582 static __init void event_trace_self_tests(void)
2583 {
2584 struct ftrace_subsystem_dir *dir;
2585 struct ftrace_event_file *file;
2586 struct ftrace_event_call *call;
2587 struct event_subsystem *system;
2588 struct trace_array *tr;
2589 int ret;
2590
2591 tr = top_trace_array();
2592 if (!tr)
2593 return;
2594
2595 pr_info("Running tests on trace events:\n");
2596
2597 list_for_each_entry(file, &tr->events, list) {
2598
2599 call = file->event_call;
2600
2601 /* Only test those that have a probe */
2602 if (!call->class || !call->class->probe)
2603 continue;
2604
2605 /*
2606 * Testing syscall events here is pretty useless, but
2607 * we still do it if configured. But this is time consuming.
2608 * What we really need is a user thread to perform the
2609 * syscalls as we test.
2610 */
2611 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
2612 if (call->class->system &&
2613 strcmp(call->class->system, "syscalls") == 0)
2614 continue;
2615 #endif
2616
2617 pr_info("Testing event %s: ", ftrace_event_name(call));
2618
2619 /*
2620 * If an event is already enabled, someone is using
2621 * it and the self test should not be on.
2622 */
2623 if (file->flags & FTRACE_EVENT_FL_ENABLED) {
2624 pr_warn("Enabled event during self test!\n");
2625 WARN_ON_ONCE(1);
2626 continue;
2627 }
2628
2629 ftrace_event_enable_disable(file, 1);
2630 event_test_stuff();
2631 ftrace_event_enable_disable(file, 0);
2632
2633 pr_cont("OK\n");
2634 }
2635
2636 /* Now test at the sub system level */
2637
2638 pr_info("Running tests on trace event systems:\n");
2639
2640 list_for_each_entry(dir, &tr->systems, list) {
2641
2642 system = dir->subsystem;
2643
2644 /* the ftrace system is special, skip it */
2645 if (strcmp(system->name, "ftrace") == 0)
2646 continue;
2647
2648 pr_info("Testing event system %s: ", system->name);
2649
2650 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
2651 if (WARN_ON_ONCE(ret)) {
2652 pr_warn("error enabling system %s\n",
2653 system->name);
2654 continue;
2655 }
2656
2657 event_test_stuff();
2658
2659 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
2660 if (WARN_ON_ONCE(ret)) {
2661 pr_warn("error disabling system %s\n",
2662 system->name);
2663 continue;
2664 }
2665
2666 pr_cont("OK\n");
2667 }
2668
2669 /* Test with all events enabled */
2670
2671 pr_info("Running tests on all trace events:\n");
2672 pr_info("Testing all events: ");
2673
2674 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
2675 if (WARN_ON_ONCE(ret)) {
2676 pr_warn("error enabling all events\n");
2677 return;
2678 }
2679
2680 event_test_stuff();
2681
2682 /* reset sysname */
2683 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
2684 if (WARN_ON_ONCE(ret)) {
2685 pr_warn("error disabling all events\n");
2686 return;
2687 }
2688
2689 pr_cont("OK\n");
2690 }
2691
2692 #ifdef CONFIG_FUNCTION_TRACER
2693
2694 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
2695
2696 static void
2697 function_test_events_call(unsigned long ip, unsigned long parent_ip,
2698 struct ftrace_ops *op, struct pt_regs *pt_regs)
2699 {
2700 struct ring_buffer_event *event;
2701 struct ring_buffer *buffer;
2702 struct ftrace_entry *entry;
2703 unsigned long flags;
2704 long disabled;
2705 int cpu;
2706 int pc;
2707
2708 pc = preempt_count();
2709 preempt_disable_notrace();
2710 cpu = raw_smp_processor_id();
2711 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
2712
2713 if (disabled != 1)
2714 goto out;
2715
2716 local_save_flags(flags);
2717
2718 event = trace_current_buffer_lock_reserve(&buffer,
2719 TRACE_FN, sizeof(*entry),
2720 flags, pc);
2721 if (!event)
2722 goto out;
2723 entry = ring_buffer_event_data(event);
2724 entry->ip = ip;
2725 entry->parent_ip = parent_ip;
2726
2727 trace_buffer_unlock_commit(buffer, event, flags, pc);
2728
2729 out:
2730 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
2731 preempt_enable_notrace();
2732 }
2733
2734 static struct ftrace_ops trace_ops __initdata =
2735 {
2736 .func = function_test_events_call,
2737 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
2738 };
2739
2740 static __init void event_trace_self_test_with_function(void)
2741 {
2742 int ret;
2743 ret = register_ftrace_function(&trace_ops);
2744 if (WARN_ON(ret < 0)) {
2745 pr_info("Failed to enable function tracer for event tests\n");
2746 return;
2747 }
2748 pr_info("Running tests again, along with the function tracer\n");
2749 event_trace_self_tests();
2750 unregister_ftrace_function(&trace_ops);
2751 }
2752 #else
2753 static __init void event_trace_self_test_with_function(void)
2754 {
2755 }
2756 #endif
2757
2758 static __init int event_trace_self_tests_init(void)
2759 {
2760 if (!tracing_selftest_disabled) {
2761 event_trace_self_tests();
2762 event_trace_self_test_with_function();
2763 }
2764
2765 return 0;
2766 }
2767
2768 late_initcall(event_trace_self_tests_init);
2769
2770 #endif
Linux kernel - Deliverables
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