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Linux 3.13-rc4
[mirror_ubuntu-bionic-kernel.git] / kernel / trace / trace_events.c
1 /*
2 * event tracer
3 *
4 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
5 *
6 * - Added format output of fields of the trace point.
7 * This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
8 *
9 */
10
11 #include <linux/workqueue.h>
12 #include <linux/spinlock.h>
13 #include <linux/kthread.h>
14 #include <linux/debugfs.h>
15 #include <linux/uaccess.h>
16 #include <linux/module.h>
17 #include <linux/ctype.h>
18 #include <linux/slab.h>
19 #include <linux/delay.h>
20
21 #include <asm/setup.h>
22
23 #include "trace_output.h"
24
25 #undef TRACE_SYSTEM
26 #define TRACE_SYSTEM "TRACE_SYSTEM"
27
28 DEFINE_MUTEX(event_mutex);
29
30 DEFINE_MUTEX(event_storage_mutex);
31 EXPORT_SYMBOL_GPL(event_storage_mutex);
32
33 char event_storage[EVENT_STORAGE_SIZE];
34 EXPORT_SYMBOL_GPL(event_storage);
35
36 LIST_HEAD(ftrace_events);
37 static LIST_HEAD(ftrace_common_fields);
38
39 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
40
41 static struct kmem_cache *field_cachep;
42 static struct kmem_cache *file_cachep;
43
44 #define SYSTEM_FL_FREE_NAME (1 << 31)
45
46 static inline int system_refcount(struct event_subsystem *system)
47 {
48 return system->ref_count & ~SYSTEM_FL_FREE_NAME;
49 }
50
51 static int system_refcount_inc(struct event_subsystem *system)
52 {
53 return (system->ref_count++) & ~SYSTEM_FL_FREE_NAME;
54 }
55
56 static int system_refcount_dec(struct event_subsystem *system)
57 {
58 return (--system->ref_count) & ~SYSTEM_FL_FREE_NAME;
59 }
60
61 /* Double loops, do not use break, only goto's work */
62 #define do_for_each_event_file(tr, file) \
63 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
64 list_for_each_entry(file, &tr->events, list)
65
66 #define do_for_each_event_file_safe(tr, file) \
67 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
68 struct ftrace_event_file *___n; \
69 list_for_each_entry_safe(file, ___n, &tr->events, list)
70
71 #define while_for_each_event_file() \
72 }
73
74 static struct list_head *
75 trace_get_fields(struct ftrace_event_call *event_call)
76 {
77 if (!event_call->class->get_fields)
78 return &event_call->class->fields;
79 return event_call->class->get_fields(event_call);
80 }
81
82 static struct ftrace_event_field *
83 __find_event_field(struct list_head *head, char *name)
84 {
85 struct ftrace_event_field *field;
86
87 list_for_each_entry(field, head, link) {
88 if (!strcmp(field->name, name))
89 return field;
90 }
91
92 return NULL;
93 }
94
95 struct ftrace_event_field *
96 trace_find_event_field(struct ftrace_event_call *call, char *name)
97 {
98 struct ftrace_event_field *field;
99 struct list_head *head;
100
101 field = __find_event_field(&ftrace_common_fields, name);
102 if (field)
103 return field;
104
105 head = trace_get_fields(call);
106 return __find_event_field(head, name);
107 }
108
109 static int __trace_define_field(struct list_head *head, const char *type,
110 const char *name, int offset, int size,
111 int is_signed, int filter_type)
112 {
113 struct ftrace_event_field *field;
114
115 field = kmem_cache_alloc(field_cachep, GFP_TRACE);
116 if (!field)
117 return -ENOMEM;
118
119 field->name = name;
120 field->type = type;
121
122 if (filter_type == FILTER_OTHER)
123 field->filter_type = filter_assign_type(type);
124 else
125 field->filter_type = filter_type;
126
127 field->offset = offset;
128 field->size = size;
129 field->is_signed = is_signed;
130
131 list_add(&field->link, head);
132
133 return 0;
134 }
135
136 int trace_define_field(struct ftrace_event_call *call, const char *type,
137 const char *name, int offset, int size, int is_signed,
138 int filter_type)
139 {
140 struct list_head *head;
141
142 if (WARN_ON(!call->class))
143 return 0;
144
145 head = trace_get_fields(call);
146 return __trace_define_field(head, type, name, offset, size,
147 is_signed, filter_type);
148 }
149 EXPORT_SYMBOL_GPL(trace_define_field);
150
151 #define __common_field(type, item) \
152 ret = __trace_define_field(&ftrace_common_fields, #type, \
153 "common_" #item, \
154 offsetof(typeof(ent), item), \
155 sizeof(ent.item), \
156 is_signed_type(type), FILTER_OTHER); \
157 if (ret) \
158 return ret;
159
160 static int trace_define_common_fields(void)
161 {
162 int ret;
163 struct trace_entry ent;
164
165 __common_field(unsigned short, type);
166 __common_field(unsigned char, flags);
167 __common_field(unsigned char, preempt_count);
168 __common_field(int, pid);
169
170 return ret;
171 }
172
173 static void trace_destroy_fields(struct ftrace_event_call *call)
174 {
175 struct ftrace_event_field *field, *next;
176 struct list_head *head;
177
178 head = trace_get_fields(call);
179 list_for_each_entry_safe(field, next, head, link) {
180 list_del(&field->link);
181 kmem_cache_free(field_cachep, field);
182 }
183 }
184
185 int trace_event_raw_init(struct ftrace_event_call *call)
186 {
187 int id;
188
189 id = register_ftrace_event(&call->event);
190 if (!id)
191 return -ENODEV;
192
193 return 0;
194 }
195 EXPORT_SYMBOL_GPL(trace_event_raw_init);
196
197 int ftrace_event_reg(struct ftrace_event_call *call,
198 enum trace_reg type, void *data)
199 {
200 struct ftrace_event_file *file = data;
201
202 switch (type) {
203 case TRACE_REG_REGISTER:
204 return tracepoint_probe_register(call->name,
205 call->class->probe,
206 file);
207 case TRACE_REG_UNREGISTER:
208 tracepoint_probe_unregister(call->name,
209 call->class->probe,
210 file);
211 return 0;
212
213 #ifdef CONFIG_PERF_EVENTS
214 case TRACE_REG_PERF_REGISTER:
215 return tracepoint_probe_register(call->name,
216 call->class->perf_probe,
217 call);
218 case TRACE_REG_PERF_UNREGISTER:
219 tracepoint_probe_unregister(call->name,
220 call->class->perf_probe,
221 call);
222 return 0;
223 case TRACE_REG_PERF_OPEN:
224 case TRACE_REG_PERF_CLOSE:
225 case TRACE_REG_PERF_ADD:
226 case TRACE_REG_PERF_DEL:
227 return 0;
228 #endif
229 }
230 return 0;
231 }
232 EXPORT_SYMBOL_GPL(ftrace_event_reg);
233
234 void trace_event_enable_cmd_record(bool enable)
235 {
236 struct ftrace_event_file *file;
237 struct trace_array *tr;
238
239 mutex_lock(&event_mutex);
240 do_for_each_event_file(tr, file) {
241
242 if (!(file->flags & FTRACE_EVENT_FL_ENABLED))
243 continue;
244
245 if (enable) {
246 tracing_start_cmdline_record();
247 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
248 } else {
249 tracing_stop_cmdline_record();
250 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
251 }
252 } while_for_each_event_file();
253 mutex_unlock(&event_mutex);
254 }
255
256 static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
257 int enable, int soft_disable)
258 {
259 struct ftrace_event_call *call = file->event_call;
260 int ret = 0;
261 int disable;
262
263 switch (enable) {
264 case 0:
265 /*
266 * When soft_disable is set and enable is cleared, the sm_ref
267 * reference counter is decremented. If it reaches 0, we want
268 * to clear the SOFT_DISABLED flag but leave the event in the
269 * state that it was. That is, if the event was enabled and
270 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
271 * is set we do not want the event to be enabled before we
272 * clear the bit.
273 *
274 * When soft_disable is not set but the SOFT_MODE flag is,
275 * we do nothing. Do not disable the tracepoint, otherwise
276 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
277 */
278 if (soft_disable) {
279 if (atomic_dec_return(&file->sm_ref) > 0)
280 break;
281 disable = file->flags & FTRACE_EVENT_FL_SOFT_DISABLED;
282 clear_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
283 } else
284 disable = !(file->flags & FTRACE_EVENT_FL_SOFT_MODE);
285
286 if (disable && (file->flags & FTRACE_EVENT_FL_ENABLED)) {
287 clear_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
288 if (file->flags & FTRACE_EVENT_FL_RECORDED_CMD) {
289 tracing_stop_cmdline_record();
290 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
291 }
292 call->class->reg(call, TRACE_REG_UNREGISTER, file);
293 }
294 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
295 if (file->flags & FTRACE_EVENT_FL_SOFT_MODE)
296 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
297 else
298 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
299 break;
300 case 1:
301 /*
302 * When soft_disable is set and enable is set, we want to
303 * register the tracepoint for the event, but leave the event
304 * as is. That means, if the event was already enabled, we do
305 * nothing (but set SOFT_MODE). If the event is disabled, we
306 * set SOFT_DISABLED before enabling the event tracepoint, so
307 * it still seems to be disabled.
308 */
309 if (!soft_disable)
310 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
311 else {
312 if (atomic_inc_return(&file->sm_ref) > 1)
313 break;
314 set_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
315 }
316
317 if (!(file->flags & FTRACE_EVENT_FL_ENABLED)) {
318
319 /* Keep the event disabled, when going to SOFT_MODE. */
320 if (soft_disable)
321 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
322
323 if (trace_flags & TRACE_ITER_RECORD_CMD) {
324 tracing_start_cmdline_record();
325 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
326 }
327 ret = call->class->reg(call, TRACE_REG_REGISTER, file);
328 if (ret) {
329 tracing_stop_cmdline_record();
330 pr_info("event trace: Could not enable event "
331 "%s\n", call->name);
332 break;
333 }
334 set_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
335
336 /* WAS_ENABLED gets set but never cleared. */
337 call->flags |= TRACE_EVENT_FL_WAS_ENABLED;
338 }
339 break;
340 }
341
342 return ret;
343 }
344
345 static int ftrace_event_enable_disable(struct ftrace_event_file *file,
346 int enable)
347 {
348 return __ftrace_event_enable_disable(file, enable, 0);
349 }
350
351 static void ftrace_clear_events(struct trace_array *tr)
352 {
353 struct ftrace_event_file *file;
354
355 mutex_lock(&event_mutex);
356 list_for_each_entry(file, &tr->events, list) {
357 ftrace_event_enable_disable(file, 0);
358 }
359 mutex_unlock(&event_mutex);
360 }
361
362 static void __put_system(struct event_subsystem *system)
363 {
364 struct event_filter *filter = system->filter;
365
366 WARN_ON_ONCE(system_refcount(system) == 0);
367 if (system_refcount_dec(system))
368 return;
369
370 list_del(&system->list);
371
372 if (filter) {
373 kfree(filter->filter_string);
374 kfree(filter);
375 }
376 if (system->ref_count & SYSTEM_FL_FREE_NAME)
377 kfree(system->name);
378 kfree(system);
379 }
380
381 static void __get_system(struct event_subsystem *system)
382 {
383 WARN_ON_ONCE(system_refcount(system) == 0);
384 system_refcount_inc(system);
385 }
386
387 static void __get_system_dir(struct ftrace_subsystem_dir *dir)
388 {
389 WARN_ON_ONCE(dir->ref_count == 0);
390 dir->ref_count++;
391 __get_system(dir->subsystem);
392 }
393
394 static void __put_system_dir(struct ftrace_subsystem_dir *dir)
395 {
396 WARN_ON_ONCE(dir->ref_count == 0);
397 /* If the subsystem is about to be freed, the dir must be too */
398 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
399
400 __put_system(dir->subsystem);
401 if (!--dir->ref_count)
402 kfree(dir);
403 }
404
405 static void put_system(struct ftrace_subsystem_dir *dir)
406 {
407 mutex_lock(&event_mutex);
408 __put_system_dir(dir);
409 mutex_unlock(&event_mutex);
410 }
411
412 static void remove_subsystem(struct ftrace_subsystem_dir *dir)
413 {
414 if (!dir)
415 return;
416
417 if (!--dir->nr_events) {
418 debugfs_remove_recursive(dir->entry);
419 list_del(&dir->list);
420 __put_system_dir(dir);
421 }
422 }
423
424 static void *event_file_data(struct file *filp)
425 {
426 return ACCESS_ONCE(file_inode(filp)->i_private);
427 }
428
429 static void remove_event_file_dir(struct ftrace_event_file *file)
430 {
431 struct dentry *dir = file->dir;
432 struct dentry *child;
433
434 if (dir) {
435 spin_lock(&dir->d_lock); /* probably unneeded */
436 list_for_each_entry(child, &dir->d_subdirs, d_u.d_child) {
437 if (child->d_inode) /* probably unneeded */
438 child->d_inode->i_private = NULL;
439 }
440 spin_unlock(&dir->d_lock);
441
442 debugfs_remove_recursive(dir);
443 }
444
445 list_del(&file->list);
446 remove_subsystem(file->system);
447 kmem_cache_free(file_cachep, file);
448 }
449
450 /*
451 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
452 */
453 static int
454 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
455 const char *sub, const char *event, int set)
456 {
457 struct ftrace_event_file *file;
458 struct ftrace_event_call *call;
459 int ret = -EINVAL;
460
461 list_for_each_entry(file, &tr->events, list) {
462
463 call = file->event_call;
464
465 if (!call->name || !call->class || !call->class->reg)
466 continue;
467
468 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
469 continue;
470
471 if (match &&
472 strcmp(match, call->name) != 0 &&
473 strcmp(match, call->class->system) != 0)
474 continue;
475
476 if (sub && strcmp(sub, call->class->system) != 0)
477 continue;
478
479 if (event && strcmp(event, call->name) != 0)
480 continue;
481
482 ftrace_event_enable_disable(file, set);
483
484 ret = 0;
485 }
486
487 return ret;
488 }
489
490 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
491 const char *sub, const char *event, int set)
492 {
493 int ret;
494
495 mutex_lock(&event_mutex);
496 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
497 mutex_unlock(&event_mutex);
498
499 return ret;
500 }
501
502 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
503 {
504 char *event = NULL, *sub = NULL, *match;
505
506 /*
507 * The buf format can be <subsystem>:<event-name>
508 * *:<event-name> means any event by that name.
509 * :<event-name> is the same.
510 *
511 * <subsystem>:* means all events in that subsystem
512 * <subsystem>: means the same.
513 *
514 * <name> (no ':') means all events in a subsystem with
515 * the name <name> or any event that matches <name>
516 */
517
518 match = strsep(&buf, ":");
519 if (buf) {
520 sub = match;
521 event = buf;
522 match = NULL;
523
524 if (!strlen(sub) || strcmp(sub, "*") == 0)
525 sub = NULL;
526 if (!strlen(event) || strcmp(event, "*") == 0)
527 event = NULL;
528 }
529
530 return __ftrace_set_clr_event(tr, match, sub, event, set);
531 }
532
533 /**
534 * trace_set_clr_event - enable or disable an event
535 * @system: system name to match (NULL for any system)
536 * @event: event name to match (NULL for all events, within system)
537 * @set: 1 to enable, 0 to disable
538 *
539 * This is a way for other parts of the kernel to enable or disable
540 * event recording.
541 *
542 * Returns 0 on success, -EINVAL if the parameters do not match any
543 * registered events.
544 */
545 int trace_set_clr_event(const char *system, const char *event, int set)
546 {
547 struct trace_array *tr = top_trace_array();
548
549 return __ftrace_set_clr_event(tr, NULL, system, event, set);
550 }
551 EXPORT_SYMBOL_GPL(trace_set_clr_event);
552
553 /* 128 should be much more than enough */
554 #define EVENT_BUF_SIZE 127
555
556 static ssize_t
557 ftrace_event_write(struct file *file, const char __user *ubuf,
558 size_t cnt, loff_t *ppos)
559 {
560 struct trace_parser parser;
561 struct seq_file *m = file->private_data;
562 struct trace_array *tr = m->private;
563 ssize_t read, ret;
564
565 if (!cnt)
566 return 0;
567
568 ret = tracing_update_buffers();
569 if (ret < 0)
570 return ret;
571
572 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
573 return -ENOMEM;
574
575 read = trace_get_user(&parser, ubuf, cnt, ppos);
576
577 if (read >= 0 && trace_parser_loaded((&parser))) {
578 int set = 1;
579
580 if (*parser.buffer == '!')
581 set = 0;
582
583 parser.buffer[parser.idx] = 0;
584
585 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
586 if (ret)
587 goto out_put;
588 }
589
590 ret = read;
591
592 out_put:
593 trace_parser_put(&parser);
594
595 return ret;
596 }
597
598 static void *
599 t_next(struct seq_file *m, void *v, loff_t *pos)
600 {
601 struct ftrace_event_file *file = v;
602 struct ftrace_event_call *call;
603 struct trace_array *tr = m->private;
604
605 (*pos)++;
606
607 list_for_each_entry_continue(file, &tr->events, list) {
608 call = file->event_call;
609 /*
610 * The ftrace subsystem is for showing formats only.
611 * They can not be enabled or disabled via the event files.
612 */
613 if (call->class && call->class->reg)
614 return file;
615 }
616
617 return NULL;
618 }
619
620 static void *t_start(struct seq_file *m, loff_t *pos)
621 {
622 struct ftrace_event_file *file;
623 struct trace_array *tr = m->private;
624 loff_t l;
625
626 mutex_lock(&event_mutex);
627
628 file = list_entry(&tr->events, struct ftrace_event_file, list);
629 for (l = 0; l <= *pos; ) {
630 file = t_next(m, file, &l);
631 if (!file)
632 break;
633 }
634 return file;
635 }
636
637 static void *
638 s_next(struct seq_file *m, void *v, loff_t *pos)
639 {
640 struct ftrace_event_file *file = v;
641 struct trace_array *tr = m->private;
642
643 (*pos)++;
644
645 list_for_each_entry_continue(file, &tr->events, list) {
646 if (file->flags & FTRACE_EVENT_FL_ENABLED)
647 return file;
648 }
649
650 return NULL;
651 }
652
653 static void *s_start(struct seq_file *m, loff_t *pos)
654 {
655 struct ftrace_event_file *file;
656 struct trace_array *tr = m->private;
657 loff_t l;
658
659 mutex_lock(&event_mutex);
660
661 file = list_entry(&tr->events, struct ftrace_event_file, list);
662 for (l = 0; l <= *pos; ) {
663 file = s_next(m, file, &l);
664 if (!file)
665 break;
666 }
667 return file;
668 }
669
670 static int t_show(struct seq_file *m, void *v)
671 {
672 struct ftrace_event_file *file = v;
673 struct ftrace_event_call *call = file->event_call;
674
675 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
676 seq_printf(m, "%s:", call->class->system);
677 seq_printf(m, "%s\n", call->name);
678
679 return 0;
680 }
681
682 static void t_stop(struct seq_file *m, void *p)
683 {
684 mutex_unlock(&event_mutex);
685 }
686
687 static ssize_t
688 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
689 loff_t *ppos)
690 {
691 struct ftrace_event_file *file;
692 unsigned long flags;
693 char buf[4] = "0";
694
695 mutex_lock(&event_mutex);
696 file = event_file_data(filp);
697 if (likely(file))
698 flags = file->flags;
699 mutex_unlock(&event_mutex);
700
701 if (!file)
702 return -ENODEV;
703
704 if (flags & FTRACE_EVENT_FL_ENABLED &&
705 !(flags & FTRACE_EVENT_FL_SOFT_DISABLED))
706 strcpy(buf, "1");
707
708 if (flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
709 flags & FTRACE_EVENT_FL_SOFT_MODE)
710 strcat(buf, "*");
711
712 strcat(buf, "\n");
713
714 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
715 }
716
717 static ssize_t
718 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
719 loff_t *ppos)
720 {
721 struct ftrace_event_file *file;
722 unsigned long val;
723 int ret;
724
725 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
726 if (ret)
727 return ret;
728
729 ret = tracing_update_buffers();
730 if (ret < 0)
731 return ret;
732
733 switch (val) {
734 case 0:
735 case 1:
736 ret = -ENODEV;
737 mutex_lock(&event_mutex);
738 file = event_file_data(filp);
739 if (likely(file))
740 ret = ftrace_event_enable_disable(file, val);
741 mutex_unlock(&event_mutex);
742 break;
743
744 default:
745 return -EINVAL;
746 }
747
748 *ppos += cnt;
749
750 return ret ? ret : cnt;
751 }
752
753 static ssize_t
754 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
755 loff_t *ppos)
756 {
757 const char set_to_char[4] = { '?', '0', '1', 'X' };
758 struct ftrace_subsystem_dir *dir = filp->private_data;
759 struct event_subsystem *system = dir->subsystem;
760 struct ftrace_event_call *call;
761 struct ftrace_event_file *file;
762 struct trace_array *tr = dir->tr;
763 char buf[2];
764 int set = 0;
765 int ret;
766
767 mutex_lock(&event_mutex);
768 list_for_each_entry(file, &tr->events, list) {
769 call = file->event_call;
770 if (!call->name || !call->class || !call->class->reg)
771 continue;
772
773 if (system && strcmp(call->class->system, system->name) != 0)
774 continue;
775
776 /*
777 * We need to find out if all the events are set
778 * or if all events or cleared, or if we have
779 * a mixture.
780 */
781 set |= (1 << !!(file->flags & FTRACE_EVENT_FL_ENABLED));
782
783 /*
784 * If we have a mixture, no need to look further.
785 */
786 if (set == 3)
787 break;
788 }
789 mutex_unlock(&event_mutex);
790
791 buf[0] = set_to_char[set];
792 buf[1] = '\n';
793
794 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
795
796 return ret;
797 }
798
799 static ssize_t
800 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
801 loff_t *ppos)
802 {
803 struct ftrace_subsystem_dir *dir = filp->private_data;
804 struct event_subsystem *system = dir->subsystem;
805 const char *name = NULL;
806 unsigned long val;
807 ssize_t ret;
808
809 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
810 if (ret)
811 return ret;
812
813 ret = tracing_update_buffers();
814 if (ret < 0)
815 return ret;
816
817 if (val != 0 && val != 1)
818 return -EINVAL;
819
820 /*
821 * Opening of "enable" adds a ref count to system,
822 * so the name is safe to use.
823 */
824 if (system)
825 name = system->name;
826
827 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
828 if (ret)
829 goto out;
830
831 ret = cnt;
832
833 out:
834 *ppos += cnt;
835
836 return ret;
837 }
838
839 enum {
840 FORMAT_HEADER = 1,
841 FORMAT_FIELD_SEPERATOR = 2,
842 FORMAT_PRINTFMT = 3,
843 };
844
845 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
846 {
847 struct ftrace_event_call *call = event_file_data(m->private);
848 struct list_head *common_head = &ftrace_common_fields;
849 struct list_head *head = trace_get_fields(call);
850 struct list_head *node = v;
851
852 (*pos)++;
853
854 switch ((unsigned long)v) {
855 case FORMAT_HEADER:
856 node = common_head;
857 break;
858
859 case FORMAT_FIELD_SEPERATOR:
860 node = head;
861 break;
862
863 case FORMAT_PRINTFMT:
864 /* all done */
865 return NULL;
866 }
867
868 node = node->prev;
869 if (node == common_head)
870 return (void *)FORMAT_FIELD_SEPERATOR;
871 else if (node == head)
872 return (void *)FORMAT_PRINTFMT;
873 else
874 return node;
875 }
876
877 static int f_show(struct seq_file *m, void *v)
878 {
879 struct ftrace_event_call *call = event_file_data(m->private);
880 struct ftrace_event_field *field;
881 const char *array_descriptor;
882
883 switch ((unsigned long)v) {
884 case FORMAT_HEADER:
885 seq_printf(m, "name: %s\n", call->name);
886 seq_printf(m, "ID: %d\n", call->event.type);
887 seq_printf(m, "format:\n");
888 return 0;
889
890 case FORMAT_FIELD_SEPERATOR:
891 seq_putc(m, '\n');
892 return 0;
893
894 case FORMAT_PRINTFMT:
895 seq_printf(m, "\nprint fmt: %s\n",
896 call->print_fmt);
897 return 0;
898 }
899
900 field = list_entry(v, struct ftrace_event_field, link);
901 /*
902 * Smartly shows the array type(except dynamic array).
903 * Normal:
904 * field:TYPE VAR
905 * If TYPE := TYPE[LEN], it is shown:
906 * field:TYPE VAR[LEN]
907 */
908 array_descriptor = strchr(field->type, '[');
909
910 if (!strncmp(field->type, "__data_loc", 10))
911 array_descriptor = NULL;
912
913 if (!array_descriptor)
914 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
915 field->type, field->name, field->offset,
916 field->size, !!field->is_signed);
917 else
918 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
919 (int)(array_descriptor - field->type),
920 field->type, field->name,
921 array_descriptor, field->offset,
922 field->size, !!field->is_signed);
923
924 return 0;
925 }
926
927 static void *f_start(struct seq_file *m, loff_t *pos)
928 {
929 void *p = (void *)FORMAT_HEADER;
930 loff_t l = 0;
931
932 /* ->stop() is called even if ->start() fails */
933 mutex_lock(&event_mutex);
934 if (!event_file_data(m->private))
935 return ERR_PTR(-ENODEV);
936
937 while (l < *pos && p)
938 p = f_next(m, p, &l);
939
940 return p;
941 }
942
943 static void f_stop(struct seq_file *m, void *p)
944 {
945 mutex_unlock(&event_mutex);
946 }
947
948 static const struct seq_operations trace_format_seq_ops = {
949 .start = f_start,
950 .next = f_next,
951 .stop = f_stop,
952 .show = f_show,
953 };
954
955 static int trace_format_open(struct inode *inode, struct file *file)
956 {
957 struct seq_file *m;
958 int ret;
959
960 ret = seq_open(file, &trace_format_seq_ops);
961 if (ret < 0)
962 return ret;
963
964 m = file->private_data;
965 m->private = file;
966
967 return 0;
968 }
969
970 static ssize_t
971 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
972 {
973 int id = (long)event_file_data(filp);
974 char buf[32];
975 int len;
976
977 if (*ppos)
978 return 0;
979
980 if (unlikely(!id))
981 return -ENODEV;
982
983 len = sprintf(buf, "%d\n", id);
984
985 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
986 }
987
988 static ssize_t
989 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
990 loff_t *ppos)
991 {
992 struct ftrace_event_file *file;
993 struct trace_seq *s;
994 int r = -ENODEV;
995
996 if (*ppos)
997 return 0;
998
999 s = kmalloc(sizeof(*s), GFP_KERNEL);
1000
1001 if (!s)
1002 return -ENOMEM;
1003
1004 trace_seq_init(s);
1005
1006 mutex_lock(&event_mutex);
1007 file = event_file_data(filp);
1008 if (file)
1009 print_event_filter(file, s);
1010 mutex_unlock(&event_mutex);
1011
1012 if (file)
1013 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1014
1015 kfree(s);
1016
1017 return r;
1018 }
1019
1020 static ssize_t
1021 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1022 loff_t *ppos)
1023 {
1024 struct ftrace_event_file *file;
1025 char *buf;
1026 int err = -ENODEV;
1027
1028 if (cnt >= PAGE_SIZE)
1029 return -EINVAL;
1030
1031 buf = (char *)__get_free_page(GFP_TEMPORARY);
1032 if (!buf)
1033 return -ENOMEM;
1034
1035 if (copy_from_user(buf, ubuf, cnt)) {
1036 free_page((unsigned long) buf);
1037 return -EFAULT;
1038 }
1039 buf[cnt] = '\0';
1040
1041 mutex_lock(&event_mutex);
1042 file = event_file_data(filp);
1043 if (file)
1044 err = apply_event_filter(file, buf);
1045 mutex_unlock(&event_mutex);
1046
1047 free_page((unsigned long) buf);
1048 if (err < 0)
1049 return err;
1050
1051 *ppos += cnt;
1052
1053 return cnt;
1054 }
1055
1056 static LIST_HEAD(event_subsystems);
1057
1058 static int subsystem_open(struct inode *inode, struct file *filp)
1059 {
1060 struct event_subsystem *system = NULL;
1061 struct ftrace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1062 struct trace_array *tr;
1063 int ret;
1064
1065 if (tracing_is_disabled())
1066 return -ENODEV;
1067
1068 /* Make sure the system still exists */
1069 mutex_lock(&trace_types_lock);
1070 mutex_lock(&event_mutex);
1071 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1072 list_for_each_entry(dir, &tr->systems, list) {
1073 if (dir == inode->i_private) {
1074 /* Don't open systems with no events */
1075 if (dir->nr_events) {
1076 __get_system_dir(dir);
1077 system = dir->subsystem;
1078 }
1079 goto exit_loop;
1080 }
1081 }
1082 }
1083 exit_loop:
1084 mutex_unlock(&event_mutex);
1085 mutex_unlock(&trace_types_lock);
1086
1087 if (!system)
1088 return -ENODEV;
1089
1090 /* Some versions of gcc think dir can be uninitialized here */
1091 WARN_ON(!dir);
1092
1093 /* Still need to increment the ref count of the system */
1094 if (trace_array_get(tr) < 0) {
1095 put_system(dir);
1096 return -ENODEV;
1097 }
1098
1099 ret = tracing_open_generic(inode, filp);
1100 if (ret < 0) {
1101 trace_array_put(tr);
1102 put_system(dir);
1103 }
1104
1105 return ret;
1106 }
1107
1108 static int system_tr_open(struct inode *inode, struct file *filp)
1109 {
1110 struct ftrace_subsystem_dir *dir;
1111 struct trace_array *tr = inode->i_private;
1112 int ret;
1113
1114 if (tracing_is_disabled())
1115 return -ENODEV;
1116
1117 if (trace_array_get(tr) < 0)
1118 return -ENODEV;
1119
1120 /* Make a temporary dir that has no system but points to tr */
1121 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1122 if (!dir) {
1123 trace_array_put(tr);
1124 return -ENOMEM;
1125 }
1126
1127 dir->tr = tr;
1128
1129 ret = tracing_open_generic(inode, filp);
1130 if (ret < 0) {
1131 trace_array_put(tr);
1132 kfree(dir);
1133 return ret;
1134 }
1135
1136 filp->private_data = dir;
1137
1138 return 0;
1139 }
1140
1141 static int subsystem_release(struct inode *inode, struct file *file)
1142 {
1143 struct ftrace_subsystem_dir *dir = file->private_data;
1144
1145 trace_array_put(dir->tr);
1146
1147 /*
1148 * If dir->subsystem is NULL, then this is a temporary
1149 * descriptor that was made for a trace_array to enable
1150 * all subsystems.
1151 */
1152 if (dir->subsystem)
1153 put_system(dir);
1154 else
1155 kfree(dir);
1156
1157 return 0;
1158 }
1159
1160 static ssize_t
1161 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1162 loff_t *ppos)
1163 {
1164 struct ftrace_subsystem_dir *dir = filp->private_data;
1165 struct event_subsystem *system = dir->subsystem;
1166 struct trace_seq *s;
1167 int r;
1168
1169 if (*ppos)
1170 return 0;
1171
1172 s = kmalloc(sizeof(*s), GFP_KERNEL);
1173 if (!s)
1174 return -ENOMEM;
1175
1176 trace_seq_init(s);
1177
1178 print_subsystem_event_filter(system, s);
1179 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1180
1181 kfree(s);
1182
1183 return r;
1184 }
1185
1186 static ssize_t
1187 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1188 loff_t *ppos)
1189 {
1190 struct ftrace_subsystem_dir *dir = filp->private_data;
1191 char *buf;
1192 int err;
1193
1194 if (cnt >= PAGE_SIZE)
1195 return -EINVAL;
1196
1197 buf = (char *)__get_free_page(GFP_TEMPORARY);
1198 if (!buf)
1199 return -ENOMEM;
1200
1201 if (copy_from_user(buf, ubuf, cnt)) {
1202 free_page((unsigned long) buf);
1203 return -EFAULT;
1204 }
1205 buf[cnt] = '\0';
1206
1207 err = apply_subsystem_event_filter(dir, buf);
1208 free_page((unsigned long) buf);
1209 if (err < 0)
1210 return err;
1211
1212 *ppos += cnt;
1213
1214 return cnt;
1215 }
1216
1217 static ssize_t
1218 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1219 {
1220 int (*func)(struct trace_seq *s) = filp->private_data;
1221 struct trace_seq *s;
1222 int r;
1223
1224 if (*ppos)
1225 return 0;
1226
1227 s = kmalloc(sizeof(*s), GFP_KERNEL);
1228 if (!s)
1229 return -ENOMEM;
1230
1231 trace_seq_init(s);
1232
1233 func(s);
1234 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1235
1236 kfree(s);
1237
1238 return r;
1239 }
1240
1241 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1242 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1243 static int ftrace_event_release(struct inode *inode, struct file *file);
1244
1245 static const struct seq_operations show_event_seq_ops = {
1246 .start = t_start,
1247 .next = t_next,
1248 .show = t_show,
1249 .stop = t_stop,
1250 };
1251
1252 static const struct seq_operations show_set_event_seq_ops = {
1253 .start = s_start,
1254 .next = s_next,
1255 .show = t_show,
1256 .stop = t_stop,
1257 };
1258
1259 static const struct file_operations ftrace_avail_fops = {
1260 .open = ftrace_event_avail_open,
1261 .read = seq_read,
1262 .llseek = seq_lseek,
1263 .release = seq_release,
1264 };
1265
1266 static const struct file_operations ftrace_set_event_fops = {
1267 .open = ftrace_event_set_open,
1268 .read = seq_read,
1269 .write = ftrace_event_write,
1270 .llseek = seq_lseek,
1271 .release = ftrace_event_release,
1272 };
1273
1274 static const struct file_operations ftrace_enable_fops = {
1275 .open = tracing_open_generic,
1276 .read = event_enable_read,
1277 .write = event_enable_write,
1278 .llseek = default_llseek,
1279 };
1280
1281 static const struct file_operations ftrace_event_format_fops = {
1282 .open = trace_format_open,
1283 .read = seq_read,
1284 .llseek = seq_lseek,
1285 .release = seq_release,
1286 };
1287
1288 static const struct file_operations ftrace_event_id_fops = {
1289 .read = event_id_read,
1290 .llseek = default_llseek,
1291 };
1292
1293 static const struct file_operations ftrace_event_filter_fops = {
1294 .open = tracing_open_generic,
1295 .read = event_filter_read,
1296 .write = event_filter_write,
1297 .llseek = default_llseek,
1298 };
1299
1300 static const struct file_operations ftrace_subsystem_filter_fops = {
1301 .open = subsystem_open,
1302 .read = subsystem_filter_read,
1303 .write = subsystem_filter_write,
1304 .llseek = default_llseek,
1305 .release = subsystem_release,
1306 };
1307
1308 static const struct file_operations ftrace_system_enable_fops = {
1309 .open = subsystem_open,
1310 .read = system_enable_read,
1311 .write = system_enable_write,
1312 .llseek = default_llseek,
1313 .release = subsystem_release,
1314 };
1315
1316 static const struct file_operations ftrace_tr_enable_fops = {
1317 .open = system_tr_open,
1318 .read = system_enable_read,
1319 .write = system_enable_write,
1320 .llseek = default_llseek,
1321 .release = subsystem_release,
1322 };
1323
1324 static const struct file_operations ftrace_show_header_fops = {
1325 .open = tracing_open_generic,
1326 .read = show_header,
1327 .llseek = default_llseek,
1328 };
1329
1330 static int
1331 ftrace_event_open(struct inode *inode, struct file *file,
1332 const struct seq_operations *seq_ops)
1333 {
1334 struct seq_file *m;
1335 int ret;
1336
1337 ret = seq_open(file, seq_ops);
1338 if (ret < 0)
1339 return ret;
1340 m = file->private_data;
1341 /* copy tr over to seq ops */
1342 m->private = inode->i_private;
1343
1344 return ret;
1345 }
1346
1347 static int ftrace_event_release(struct inode *inode, struct file *file)
1348 {
1349 struct trace_array *tr = inode->i_private;
1350
1351 trace_array_put(tr);
1352
1353 return seq_release(inode, file);
1354 }
1355
1356 static int
1357 ftrace_event_avail_open(struct inode *inode, struct file *file)
1358 {
1359 const struct seq_operations *seq_ops = &show_event_seq_ops;
1360
1361 return ftrace_event_open(inode, file, seq_ops);
1362 }
1363
1364 static int
1365 ftrace_event_set_open(struct inode *inode, struct file *file)
1366 {
1367 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1368 struct trace_array *tr = inode->i_private;
1369 int ret;
1370
1371 if (trace_array_get(tr) < 0)
1372 return -ENODEV;
1373
1374 if ((file->f_mode & FMODE_WRITE) &&
1375 (file->f_flags & O_TRUNC))
1376 ftrace_clear_events(tr);
1377
1378 ret = ftrace_event_open(inode, file, seq_ops);
1379 if (ret < 0)
1380 trace_array_put(tr);
1381 return ret;
1382 }
1383
1384 static struct event_subsystem *
1385 create_new_subsystem(const char *name)
1386 {
1387 struct event_subsystem *system;
1388
1389 /* need to create new entry */
1390 system = kmalloc(sizeof(*system), GFP_KERNEL);
1391 if (!system)
1392 return NULL;
1393
1394 system->ref_count = 1;
1395
1396 /* Only allocate if dynamic (kprobes and modules) */
1397 if (!core_kernel_data((unsigned long)name)) {
1398 system->ref_count |= SYSTEM_FL_FREE_NAME;
1399 system->name = kstrdup(name, GFP_KERNEL);
1400 if (!system->name)
1401 goto out_free;
1402 } else
1403 system->name = name;
1404
1405 system->filter = NULL;
1406
1407 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1408 if (!system->filter)
1409 goto out_free;
1410
1411 list_add(&system->list, &event_subsystems);
1412
1413 return system;
1414
1415 out_free:
1416 if (system->ref_count & SYSTEM_FL_FREE_NAME)
1417 kfree(system->name);
1418 kfree(system);
1419 return NULL;
1420 }
1421
1422 static struct dentry *
1423 event_subsystem_dir(struct trace_array *tr, const char *name,
1424 struct ftrace_event_file *file, struct dentry *parent)
1425 {
1426 struct ftrace_subsystem_dir *dir;
1427 struct event_subsystem *system;
1428 struct dentry *entry;
1429
1430 /* First see if we did not already create this dir */
1431 list_for_each_entry(dir, &tr->systems, list) {
1432 system = dir->subsystem;
1433 if (strcmp(system->name, name) == 0) {
1434 dir->nr_events++;
1435 file->system = dir;
1436 return dir->entry;
1437 }
1438 }
1439
1440 /* Now see if the system itself exists. */
1441 list_for_each_entry(system, &event_subsystems, list) {
1442 if (strcmp(system->name, name) == 0)
1443 break;
1444 }
1445 /* Reset system variable when not found */
1446 if (&system->list == &event_subsystems)
1447 system = NULL;
1448
1449 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1450 if (!dir)
1451 goto out_fail;
1452
1453 if (!system) {
1454 system = create_new_subsystem(name);
1455 if (!system)
1456 goto out_free;
1457 } else
1458 __get_system(system);
1459
1460 dir->entry = debugfs_create_dir(name, parent);
1461 if (!dir->entry) {
1462 pr_warning("Failed to create system directory %s\n", name);
1463 __put_system(system);
1464 goto out_free;
1465 }
1466
1467 dir->tr = tr;
1468 dir->ref_count = 1;
1469 dir->nr_events = 1;
1470 dir->subsystem = system;
1471 file->system = dir;
1472
1473 entry = debugfs_create_file("filter", 0644, dir->entry, dir,
1474 &ftrace_subsystem_filter_fops);
1475 if (!entry) {
1476 kfree(system->filter);
1477 system->filter = NULL;
1478 pr_warning("Could not create debugfs '%s/filter' entry\n", name);
1479 }
1480
1481 trace_create_file("enable", 0644, dir->entry, dir,
1482 &ftrace_system_enable_fops);
1483
1484 list_add(&dir->list, &tr->systems);
1485
1486 return dir->entry;
1487
1488 out_free:
1489 kfree(dir);
1490 out_fail:
1491 /* Only print this message if failed on memory allocation */
1492 if (!dir || !system)
1493 pr_warning("No memory to create event subsystem %s\n",
1494 name);
1495 return NULL;
1496 }
1497
1498 static int
1499 event_create_dir(struct dentry *parent, struct ftrace_event_file *file)
1500 {
1501 struct ftrace_event_call *call = file->event_call;
1502 struct trace_array *tr = file->tr;
1503 struct list_head *head;
1504 struct dentry *d_events;
1505 int ret;
1506
1507 /*
1508 * If the trace point header did not define TRACE_SYSTEM
1509 * then the system would be called "TRACE_SYSTEM".
1510 */
1511 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1512 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1513 if (!d_events)
1514 return -ENOMEM;
1515 } else
1516 d_events = parent;
1517
1518 file->dir = debugfs_create_dir(call->name, d_events);
1519 if (!file->dir) {
1520 pr_warning("Could not create debugfs '%s' directory\n",
1521 call->name);
1522 return -1;
1523 }
1524
1525 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1526 trace_create_file("enable", 0644, file->dir, file,
1527 &ftrace_enable_fops);
1528
1529 #ifdef CONFIG_PERF_EVENTS
1530 if (call->event.type && call->class->reg)
1531 trace_create_file("id", 0444, file->dir,
1532 (void *)(long)call->event.type,
1533 &ftrace_event_id_fops);
1534 #endif
1535
1536 /*
1537 * Other events may have the same class. Only update
1538 * the fields if they are not already defined.
1539 */
1540 head = trace_get_fields(call);
1541 if (list_empty(head)) {
1542 ret = call->class->define_fields(call);
1543 if (ret < 0) {
1544 pr_warning("Could not initialize trace point"
1545 " events/%s\n", call->name);
1546 return -1;
1547 }
1548 }
1549 trace_create_file("filter", 0644, file->dir, file,
1550 &ftrace_event_filter_fops);
1551
1552 trace_create_file("format", 0444, file->dir, call,
1553 &ftrace_event_format_fops);
1554
1555 return 0;
1556 }
1557
1558 static void remove_event_from_tracers(struct ftrace_event_call *call)
1559 {
1560 struct ftrace_event_file *file;
1561 struct trace_array *tr;
1562
1563 do_for_each_event_file_safe(tr, file) {
1564 if (file->event_call != call)
1565 continue;
1566
1567 remove_event_file_dir(file);
1568 /*
1569 * The do_for_each_event_file_safe() is
1570 * a double loop. After finding the call for this
1571 * trace_array, we use break to jump to the next
1572 * trace_array.
1573 */
1574 break;
1575 } while_for_each_event_file();
1576 }
1577
1578 static void event_remove(struct ftrace_event_call *call)
1579 {
1580 struct trace_array *tr;
1581 struct ftrace_event_file *file;
1582
1583 do_for_each_event_file(tr, file) {
1584 if (file->event_call != call)
1585 continue;
1586 ftrace_event_enable_disable(file, 0);
1587 destroy_preds(file);
1588 /*
1589 * The do_for_each_event_file() is
1590 * a double loop. After finding the call for this
1591 * trace_array, we use break to jump to the next
1592 * trace_array.
1593 */
1594 break;
1595 } while_for_each_event_file();
1596
1597 if (call->event.funcs)
1598 __unregister_ftrace_event(&call->event);
1599 remove_event_from_tracers(call);
1600 list_del(&call->list);
1601 }
1602
1603 static int event_init(struct ftrace_event_call *call)
1604 {
1605 int ret = 0;
1606
1607 if (WARN_ON(!call->name))
1608 return -EINVAL;
1609
1610 if (call->class->raw_init) {
1611 ret = call->class->raw_init(call);
1612 if (ret < 0 && ret != -ENOSYS)
1613 pr_warn("Could not initialize trace events/%s\n",
1614 call->name);
1615 }
1616
1617 return ret;
1618 }
1619
1620 static int
1621 __register_event(struct ftrace_event_call *call, struct module *mod)
1622 {
1623 int ret;
1624
1625 ret = event_init(call);
1626 if (ret < 0)
1627 return ret;
1628
1629 list_add(&call->list, &ftrace_events);
1630 call->mod = mod;
1631
1632 return 0;
1633 }
1634
1635 static struct ftrace_event_file *
1636 trace_create_new_event(struct ftrace_event_call *call,
1637 struct trace_array *tr)
1638 {
1639 struct ftrace_event_file *file;
1640
1641 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
1642 if (!file)
1643 return NULL;
1644
1645 file->event_call = call;
1646 file->tr = tr;
1647 atomic_set(&file->sm_ref, 0);
1648 list_add(&file->list, &tr->events);
1649
1650 return file;
1651 }
1652
1653 /* Add an event to a trace directory */
1654 static int
1655 __trace_add_new_event(struct ftrace_event_call *call, struct trace_array *tr)
1656 {
1657 struct ftrace_event_file *file;
1658
1659 file = trace_create_new_event(call, tr);
1660 if (!file)
1661 return -ENOMEM;
1662
1663 return event_create_dir(tr->event_dir, file);
1664 }
1665
1666 /*
1667 * Just create a decriptor for early init. A descriptor is required
1668 * for enabling events at boot. We want to enable events before
1669 * the filesystem is initialized.
1670 */
1671 static __init int
1672 __trace_early_add_new_event(struct ftrace_event_call *call,
1673 struct trace_array *tr)
1674 {
1675 struct ftrace_event_file *file;
1676
1677 file = trace_create_new_event(call, tr);
1678 if (!file)
1679 return -ENOMEM;
1680
1681 return 0;
1682 }
1683
1684 struct ftrace_module_file_ops;
1685 static void __add_event_to_tracers(struct ftrace_event_call *call);
1686
1687 /* Add an additional event_call dynamically */
1688 int trace_add_event_call(struct ftrace_event_call *call)
1689 {
1690 int ret;
1691 mutex_lock(&trace_types_lock);
1692 mutex_lock(&event_mutex);
1693
1694 ret = __register_event(call, NULL);
1695 if (ret >= 0)
1696 __add_event_to_tracers(call);
1697
1698 mutex_unlock(&event_mutex);
1699 mutex_unlock(&trace_types_lock);
1700 return ret;
1701 }
1702
1703 /*
1704 * Must be called under locking of trace_types_lock, event_mutex and
1705 * trace_event_sem.
1706 */
1707 static void __trace_remove_event_call(struct ftrace_event_call *call)
1708 {
1709 event_remove(call);
1710 trace_destroy_fields(call);
1711 destroy_call_preds(call);
1712 }
1713
1714 static int probe_remove_event_call(struct ftrace_event_call *call)
1715 {
1716 struct trace_array *tr;
1717 struct ftrace_event_file *file;
1718
1719 #ifdef CONFIG_PERF_EVENTS
1720 if (call->perf_refcount)
1721 return -EBUSY;
1722 #endif
1723 do_for_each_event_file(tr, file) {
1724 if (file->event_call != call)
1725 continue;
1726 /*
1727 * We can't rely on ftrace_event_enable_disable(enable => 0)
1728 * we are going to do, FTRACE_EVENT_FL_SOFT_MODE can suppress
1729 * TRACE_REG_UNREGISTER.
1730 */
1731 if (file->flags & FTRACE_EVENT_FL_ENABLED)
1732 return -EBUSY;
1733 /*
1734 * The do_for_each_event_file_safe() is
1735 * a double loop. After finding the call for this
1736 * trace_array, we use break to jump to the next
1737 * trace_array.
1738 */
1739 break;
1740 } while_for_each_event_file();
1741
1742 __trace_remove_event_call(call);
1743
1744 return 0;
1745 }
1746
1747 /* Remove an event_call */
1748 int trace_remove_event_call(struct ftrace_event_call *call)
1749 {
1750 int ret;
1751
1752 mutex_lock(&trace_types_lock);
1753 mutex_lock(&event_mutex);
1754 down_write(&trace_event_sem);
1755 ret = probe_remove_event_call(call);
1756 up_write(&trace_event_sem);
1757 mutex_unlock(&event_mutex);
1758 mutex_unlock(&trace_types_lock);
1759
1760 return ret;
1761 }
1762
1763 #define for_each_event(event, start, end) \
1764 for (event = start; \
1765 (unsigned long)event < (unsigned long)end; \
1766 event++)
1767
1768 #ifdef CONFIG_MODULES
1769
1770 static void trace_module_add_events(struct module *mod)
1771 {
1772 struct ftrace_event_call **call, **start, **end;
1773
1774 start = mod->trace_events;
1775 end = mod->trace_events + mod->num_trace_events;
1776
1777 for_each_event(call, start, end) {
1778 __register_event(*call, mod);
1779 __add_event_to_tracers(*call);
1780 }
1781 }
1782
1783 static void trace_module_remove_events(struct module *mod)
1784 {
1785 struct ftrace_event_call *call, *p;
1786 bool clear_trace = false;
1787
1788 down_write(&trace_event_sem);
1789 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1790 if (call->mod == mod) {
1791 if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
1792 clear_trace = true;
1793 __trace_remove_event_call(call);
1794 }
1795 }
1796 up_write(&trace_event_sem);
1797
1798 /*
1799 * It is safest to reset the ring buffer if the module being unloaded
1800 * registered any events that were used. The only worry is if
1801 * a new module gets loaded, and takes on the same id as the events
1802 * of this module. When printing out the buffer, traced events left
1803 * over from this module may be passed to the new module events and
1804 * unexpected results may occur.
1805 */
1806 if (clear_trace)
1807 tracing_reset_all_online_cpus();
1808 }
1809
1810 static int trace_module_notify(struct notifier_block *self,
1811 unsigned long val, void *data)
1812 {
1813 struct module *mod = data;
1814
1815 mutex_lock(&trace_types_lock);
1816 mutex_lock(&event_mutex);
1817 switch (val) {
1818 case MODULE_STATE_COMING:
1819 trace_module_add_events(mod);
1820 break;
1821 case MODULE_STATE_GOING:
1822 trace_module_remove_events(mod);
1823 break;
1824 }
1825 mutex_unlock(&event_mutex);
1826 mutex_unlock(&trace_types_lock);
1827
1828 return 0;
1829 }
1830
1831 static struct notifier_block trace_module_nb = {
1832 .notifier_call = trace_module_notify,
1833 .priority = 0,
1834 };
1835 #endif /* CONFIG_MODULES */
1836
1837 /* Create a new event directory structure for a trace directory. */
1838 static void
1839 __trace_add_event_dirs(struct trace_array *tr)
1840 {
1841 struct ftrace_event_call *call;
1842 int ret;
1843
1844 list_for_each_entry(call, &ftrace_events, list) {
1845 ret = __trace_add_new_event(call, tr);
1846 if (ret < 0)
1847 pr_warning("Could not create directory for event %s\n",
1848 call->name);
1849 }
1850 }
1851
1852 #ifdef CONFIG_DYNAMIC_FTRACE
1853
1854 /* Avoid typos */
1855 #define ENABLE_EVENT_STR "enable_event"
1856 #define DISABLE_EVENT_STR "disable_event"
1857
1858 struct event_probe_data {
1859 struct ftrace_event_file *file;
1860 unsigned long count;
1861 int ref;
1862 bool enable;
1863 };
1864
1865 static struct ftrace_event_file *
1866 find_event_file(struct trace_array *tr, const char *system, const char *event)
1867 {
1868 struct ftrace_event_file *file;
1869 struct ftrace_event_call *call;
1870
1871 list_for_each_entry(file, &tr->events, list) {
1872
1873 call = file->event_call;
1874
1875 if (!call->name || !call->class || !call->class->reg)
1876 continue;
1877
1878 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1879 continue;
1880
1881 if (strcmp(event, call->name) == 0 &&
1882 strcmp(system, call->class->system) == 0)
1883 return file;
1884 }
1885 return NULL;
1886 }
1887
1888 static void
1889 event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1890 {
1891 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1892 struct event_probe_data *data = *pdata;
1893
1894 if (!data)
1895 return;
1896
1897 if (data->enable)
1898 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1899 else
1900 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1901 }
1902
1903 static void
1904 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1905 {
1906 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1907 struct event_probe_data *data = *pdata;
1908
1909 if (!data)
1910 return;
1911
1912 if (!data->count)
1913 return;
1914
1915 /* Skip if the event is in a state we want to switch to */
1916 if (data->enable == !(data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
1917 return;
1918
1919 if (data->count != -1)
1920 (data->count)--;
1921
1922 event_enable_probe(ip, parent_ip, _data);
1923 }
1924
1925 static int
1926 event_enable_print(struct seq_file *m, unsigned long ip,
1927 struct ftrace_probe_ops *ops, void *_data)
1928 {
1929 struct event_probe_data *data = _data;
1930
1931 seq_printf(m, "%ps:", (void *)ip);
1932
1933 seq_printf(m, "%s:%s:%s",
1934 data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
1935 data->file->event_call->class->system,
1936 data->file->event_call->name);
1937
1938 if (data->count == -1)
1939 seq_printf(m, ":unlimited\n");
1940 else
1941 seq_printf(m, ":count=%ld\n", data->count);
1942
1943 return 0;
1944 }
1945
1946 static int
1947 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
1948 void **_data)
1949 {
1950 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1951 struct event_probe_data *data = *pdata;
1952
1953 data->ref++;
1954 return 0;
1955 }
1956
1957 static void
1958 event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
1959 void **_data)
1960 {
1961 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1962 struct event_probe_data *data = *pdata;
1963
1964 if (WARN_ON_ONCE(data->ref <= 0))
1965 return;
1966
1967 data->ref--;
1968 if (!data->ref) {
1969 /* Remove the SOFT_MODE flag */
1970 __ftrace_event_enable_disable(data->file, 0, 1);
1971 module_put(data->file->event_call->mod);
1972 kfree(data);
1973 }
1974 *pdata = NULL;
1975 }
1976
1977 static struct ftrace_probe_ops event_enable_probe_ops = {
1978 .func = event_enable_probe,
1979 .print = event_enable_print,
1980 .init = event_enable_init,
1981 .free = event_enable_free,
1982 };
1983
1984 static struct ftrace_probe_ops event_enable_count_probe_ops = {
1985 .func = event_enable_count_probe,
1986 .print = event_enable_print,
1987 .init = event_enable_init,
1988 .free = event_enable_free,
1989 };
1990
1991 static struct ftrace_probe_ops event_disable_probe_ops = {
1992 .func = event_enable_probe,
1993 .print = event_enable_print,
1994 .init = event_enable_init,
1995 .free = event_enable_free,
1996 };
1997
1998 static struct ftrace_probe_ops event_disable_count_probe_ops = {
1999 .func = event_enable_count_probe,
2000 .print = event_enable_print,
2001 .init = event_enable_init,
2002 .free = event_enable_free,
2003 };
2004
2005 static int
2006 event_enable_func(struct ftrace_hash *hash,
2007 char *glob, char *cmd, char *param, int enabled)
2008 {
2009 struct trace_array *tr = top_trace_array();
2010 struct ftrace_event_file *file;
2011 struct ftrace_probe_ops *ops;
2012 struct event_probe_data *data;
2013 const char *system;
2014 const char *event;
2015 char *number;
2016 bool enable;
2017 int ret;
2018
2019 /* hash funcs only work with set_ftrace_filter */
2020 if (!enabled || !param)
2021 return -EINVAL;
2022
2023 system = strsep(&param, ":");
2024 if (!param)
2025 return -EINVAL;
2026
2027 event = strsep(&param, ":");
2028
2029 mutex_lock(&event_mutex);
2030
2031 ret = -EINVAL;
2032 file = find_event_file(tr, system, event);
2033 if (!file)
2034 goto out;
2035
2036 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2037
2038 if (enable)
2039 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2040 else
2041 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2042
2043 if (glob[0] == '!') {
2044 unregister_ftrace_function_probe_func(glob+1, ops);
2045 ret = 0;
2046 goto out;
2047 }
2048
2049 ret = -ENOMEM;
2050 data = kzalloc(sizeof(*data), GFP_KERNEL);
2051 if (!data)
2052 goto out;
2053
2054 data->enable = enable;
2055 data->count = -1;
2056 data->file = file;
2057
2058 if (!param)
2059 goto out_reg;
2060
2061 number = strsep(&param, ":");
2062
2063 ret = -EINVAL;
2064 if (!strlen(number))
2065 goto out_free;
2066
2067 /*
2068 * We use the callback data field (which is a pointer)
2069 * as our counter.
2070 */
2071 ret = kstrtoul(number, 0, &data->count);
2072 if (ret)
2073 goto out_free;
2074
2075 out_reg:
2076 /* Don't let event modules unload while probe registered */
2077 ret = try_module_get(file->event_call->mod);
2078 if (!ret) {
2079 ret = -EBUSY;
2080 goto out_free;
2081 }
2082
2083 ret = __ftrace_event_enable_disable(file, 1, 1);
2084 if (ret < 0)
2085 goto out_put;
2086 ret = register_ftrace_function_probe(glob, ops, data);
2087 /*
2088 * The above returns on success the # of functions enabled,
2089 * but if it didn't find any functions it returns zero.
2090 * Consider no functions a failure too.
2091 */
2092 if (!ret) {
2093 ret = -ENOENT;
2094 goto out_disable;
2095 } else if (ret < 0)
2096 goto out_disable;
2097 /* Just return zero, not the number of enabled functions */
2098 ret = 0;
2099 out:
2100 mutex_unlock(&event_mutex);
2101 return ret;
2102
2103 out_disable:
2104 __ftrace_event_enable_disable(file, 0, 1);
2105 out_put:
2106 module_put(file->event_call->mod);
2107 out_free:
2108 kfree(data);
2109 goto out;
2110 }
2111
2112 static struct ftrace_func_command event_enable_cmd = {
2113 .name = ENABLE_EVENT_STR,
2114 .func = event_enable_func,
2115 };
2116
2117 static struct ftrace_func_command event_disable_cmd = {
2118 .name = DISABLE_EVENT_STR,
2119 .func = event_enable_func,
2120 };
2121
2122 static __init int register_event_cmds(void)
2123 {
2124 int ret;
2125
2126 ret = register_ftrace_command(&event_enable_cmd);
2127 if (WARN_ON(ret < 0))
2128 return ret;
2129 ret = register_ftrace_command(&event_disable_cmd);
2130 if (WARN_ON(ret < 0))
2131 unregister_ftrace_command(&event_enable_cmd);
2132 return ret;
2133 }
2134 #else
2135 static inline int register_event_cmds(void) { return 0; }
2136 #endif /* CONFIG_DYNAMIC_FTRACE */
2137
2138 /*
2139 * The top level array has already had its ftrace_event_file
2140 * descriptors created in order to allow for early events to
2141 * be recorded. This function is called after the debugfs has been
2142 * initialized, and we now have to create the files associated
2143 * to the events.
2144 */
2145 static __init void
2146 __trace_early_add_event_dirs(struct trace_array *tr)
2147 {
2148 struct ftrace_event_file *file;
2149 int ret;
2150
2151
2152 list_for_each_entry(file, &tr->events, list) {
2153 ret = event_create_dir(tr->event_dir, file);
2154 if (ret < 0)
2155 pr_warning("Could not create directory for event %s\n",
2156 file->event_call->name);
2157 }
2158 }
2159
2160 /*
2161 * For early boot up, the top trace array requires to have
2162 * a list of events that can be enabled. This must be done before
2163 * the filesystem is set up in order to allow events to be traced
2164 * early.
2165 */
2166 static __init void
2167 __trace_early_add_events(struct trace_array *tr)
2168 {
2169 struct ftrace_event_call *call;
2170 int ret;
2171
2172 list_for_each_entry(call, &ftrace_events, list) {
2173 /* Early boot up should not have any modules loaded */
2174 if (WARN_ON_ONCE(call->mod))
2175 continue;
2176
2177 ret = __trace_early_add_new_event(call, tr);
2178 if (ret < 0)
2179 pr_warning("Could not create early event %s\n",
2180 call->name);
2181 }
2182 }
2183
2184 /* Remove the event directory structure for a trace directory. */
2185 static void
2186 __trace_remove_event_dirs(struct trace_array *tr)
2187 {
2188 struct ftrace_event_file *file, *next;
2189
2190 list_for_each_entry_safe(file, next, &tr->events, list)
2191 remove_event_file_dir(file);
2192 }
2193
2194 static void __add_event_to_tracers(struct ftrace_event_call *call)
2195 {
2196 struct trace_array *tr;
2197
2198 list_for_each_entry(tr, &ftrace_trace_arrays, list)
2199 __trace_add_new_event(call, tr);
2200 }
2201
2202 extern struct ftrace_event_call *__start_ftrace_events[];
2203 extern struct ftrace_event_call *__stop_ftrace_events[];
2204
2205 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2206
2207 static __init int setup_trace_event(char *str)
2208 {
2209 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2210 ring_buffer_expanded = true;
2211 tracing_selftest_disabled = true;
2212
2213 return 1;
2214 }
2215 __setup("trace_event=", setup_trace_event);
2216
2217 /* Expects to have event_mutex held when called */
2218 static int
2219 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2220 {
2221 struct dentry *d_events;
2222 struct dentry *entry;
2223
2224 entry = debugfs_create_file("set_event", 0644, parent,
2225 tr, &ftrace_set_event_fops);
2226 if (!entry) {
2227 pr_warning("Could not create debugfs 'set_event' entry\n");
2228 return -ENOMEM;
2229 }
2230
2231 d_events = debugfs_create_dir("events", parent);
2232 if (!d_events) {
2233 pr_warning("Could not create debugfs 'events' directory\n");
2234 return -ENOMEM;
2235 }
2236
2237 /* ring buffer internal formats */
2238 trace_create_file("header_page", 0444, d_events,
2239 ring_buffer_print_page_header,
2240 &ftrace_show_header_fops);
2241
2242 trace_create_file("header_event", 0444, d_events,
2243 ring_buffer_print_entry_header,
2244 &ftrace_show_header_fops);
2245
2246 trace_create_file("enable", 0644, d_events,
2247 tr, &ftrace_tr_enable_fops);
2248
2249 tr->event_dir = d_events;
2250
2251 return 0;
2252 }
2253
2254 /**
2255 * event_trace_add_tracer - add a instance of a trace_array to events
2256 * @parent: The parent dentry to place the files/directories for events in
2257 * @tr: The trace array associated with these events
2258 *
2259 * When a new instance is created, it needs to set up its events
2260 * directory, as well as other files associated with events. It also
2261 * creates the event hierachry in the @parent/events directory.
2262 *
2263 * Returns 0 on success.
2264 */
2265 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2266 {
2267 int ret;
2268
2269 mutex_lock(&event_mutex);
2270
2271 ret = create_event_toplevel_files(parent, tr);
2272 if (ret)
2273 goto out_unlock;
2274
2275 down_write(&trace_event_sem);
2276 __trace_add_event_dirs(tr);
2277 up_write(&trace_event_sem);
2278
2279 out_unlock:
2280 mutex_unlock(&event_mutex);
2281
2282 return ret;
2283 }
2284
2285 /*
2286 * The top trace array already had its file descriptors created.
2287 * Now the files themselves need to be created.
2288 */
2289 static __init int
2290 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2291 {
2292 int ret;
2293
2294 mutex_lock(&event_mutex);
2295
2296 ret = create_event_toplevel_files(parent, tr);
2297 if (ret)
2298 goto out_unlock;
2299
2300 down_write(&trace_event_sem);
2301 __trace_early_add_event_dirs(tr);
2302 up_write(&trace_event_sem);
2303
2304 out_unlock:
2305 mutex_unlock(&event_mutex);
2306
2307 return ret;
2308 }
2309
2310 int event_trace_del_tracer(struct trace_array *tr)
2311 {
2312 mutex_lock(&event_mutex);
2313
2314 /* Disable any running events */
2315 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
2316
2317 /* Access to events are within rcu_read_lock_sched() */
2318 synchronize_sched();
2319
2320 down_write(&trace_event_sem);
2321 __trace_remove_event_dirs(tr);
2322 debugfs_remove_recursive(tr->event_dir);
2323 up_write(&trace_event_sem);
2324
2325 tr->event_dir = NULL;
2326
2327 mutex_unlock(&event_mutex);
2328
2329 return 0;
2330 }
2331
2332 static __init int event_trace_memsetup(void)
2333 {
2334 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
2335 file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC);
2336 return 0;
2337 }
2338
2339 static __init int event_trace_enable(void)
2340 {
2341 struct trace_array *tr = top_trace_array();
2342 struct ftrace_event_call **iter, *call;
2343 char *buf = bootup_event_buf;
2344 char *token;
2345 int ret;
2346
2347 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
2348
2349 call = *iter;
2350 ret = event_init(call);
2351 if (!ret)
2352 list_add(&call->list, &ftrace_events);
2353 }
2354
2355 /*
2356 * We need the top trace array to have a working set of trace
2357 * points at early init, before the debug files and directories
2358 * are created. Create the file entries now, and attach them
2359 * to the actual file dentries later.
2360 */
2361 __trace_early_add_events(tr);
2362
2363 while (true) {
2364 token = strsep(&buf, ",");
2365
2366 if (!token)
2367 break;
2368 if (!*token)
2369 continue;
2370
2371 ret = ftrace_set_clr_event(tr, token, 1);
2372 if (ret)
2373 pr_warn("Failed to enable trace event: %s\n", token);
2374 }
2375
2376 trace_printk_start_comm();
2377
2378 register_event_cmds();
2379
2380 return 0;
2381 }
2382
2383 static __init int event_trace_init(void)
2384 {
2385 struct trace_array *tr;
2386 struct dentry *d_tracer;
2387 struct dentry *entry;
2388 int ret;
2389
2390 tr = top_trace_array();
2391
2392 d_tracer = tracing_init_dentry();
2393 if (!d_tracer)
2394 return 0;
2395
2396 entry = debugfs_create_file("available_events", 0444, d_tracer,
2397 tr, &ftrace_avail_fops);
2398 if (!entry)
2399 pr_warning("Could not create debugfs "
2400 "'available_events' entry\n");
2401
2402 if (trace_define_common_fields())
2403 pr_warning("tracing: Failed to allocate common fields");
2404
2405 ret = early_event_add_tracer(d_tracer, tr);
2406 if (ret)
2407 return ret;
2408
2409 #ifdef CONFIG_MODULES
2410 ret = register_module_notifier(&trace_module_nb);
2411 if (ret)
2412 pr_warning("Failed to register trace events module notifier\n");
2413 #endif
2414 return 0;
2415 }
2416 early_initcall(event_trace_memsetup);
2417 core_initcall(event_trace_enable);
2418 fs_initcall(event_trace_init);
2419
2420 #ifdef CONFIG_FTRACE_STARTUP_TEST
2421
2422 static DEFINE_SPINLOCK(test_spinlock);
2423 static DEFINE_SPINLOCK(test_spinlock_irq);
2424 static DEFINE_MUTEX(test_mutex);
2425
2426 static __init void test_work(struct work_struct *dummy)
2427 {
2428 spin_lock(&test_spinlock);
2429 spin_lock_irq(&test_spinlock_irq);
2430 udelay(1);
2431 spin_unlock_irq(&test_spinlock_irq);
2432 spin_unlock(&test_spinlock);
2433
2434 mutex_lock(&test_mutex);
2435 msleep(1);
2436 mutex_unlock(&test_mutex);
2437 }
2438
2439 static __init int event_test_thread(void *unused)
2440 {
2441 void *test_malloc;
2442
2443 test_malloc = kmalloc(1234, GFP_KERNEL);
2444 if (!test_malloc)
2445 pr_info("failed to kmalloc\n");
2446
2447 schedule_on_each_cpu(test_work);
2448
2449 kfree(test_malloc);
2450
2451 set_current_state(TASK_INTERRUPTIBLE);
2452 while (!kthread_should_stop())
2453 schedule();
2454
2455 return 0;
2456 }
2457
2458 /*
2459 * Do various things that may trigger events.
2460 */
2461 static __init void event_test_stuff(void)
2462 {
2463 struct task_struct *test_thread;
2464
2465 test_thread = kthread_run(event_test_thread, NULL, "test-events");
2466 msleep(1);
2467 kthread_stop(test_thread);
2468 }
2469
2470 /*
2471 * For every trace event defined, we will test each trace point separately,
2472 * and then by groups, and finally all trace points.
2473 */
2474 static __init void event_trace_self_tests(void)
2475 {
2476 struct ftrace_subsystem_dir *dir;
2477 struct ftrace_event_file *file;
2478 struct ftrace_event_call *call;
2479 struct event_subsystem *system;
2480 struct trace_array *tr;
2481 int ret;
2482
2483 tr = top_trace_array();
2484
2485 pr_info("Running tests on trace events:\n");
2486
2487 list_for_each_entry(file, &tr->events, list) {
2488
2489 call = file->event_call;
2490
2491 /* Only test those that have a probe */
2492 if (!call->class || !call->class->probe)
2493 continue;
2494
2495 /*
2496 * Testing syscall events here is pretty useless, but
2497 * we still do it if configured. But this is time consuming.
2498 * What we really need is a user thread to perform the
2499 * syscalls as we test.
2500 */
2501 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
2502 if (call->class->system &&
2503 strcmp(call->class->system, "syscalls") == 0)
2504 continue;
2505 #endif
2506
2507 pr_info("Testing event %s: ", call->name);
2508
2509 /*
2510 * If an event is already enabled, someone is using
2511 * it and the self test should not be on.
2512 */
2513 if (file->flags & FTRACE_EVENT_FL_ENABLED) {
2514 pr_warning("Enabled event during self test!\n");
2515 WARN_ON_ONCE(1);
2516 continue;
2517 }
2518
2519 ftrace_event_enable_disable(file, 1);
2520 event_test_stuff();
2521 ftrace_event_enable_disable(file, 0);
2522
2523 pr_cont("OK\n");
2524 }
2525
2526 /* Now test at the sub system level */
2527
2528 pr_info("Running tests on trace event systems:\n");
2529
2530 list_for_each_entry(dir, &tr->systems, list) {
2531
2532 system = dir->subsystem;
2533
2534 /* the ftrace system is special, skip it */
2535 if (strcmp(system->name, "ftrace") == 0)
2536 continue;
2537
2538 pr_info("Testing event system %s: ", system->name);
2539
2540 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
2541 if (WARN_ON_ONCE(ret)) {
2542 pr_warning("error enabling system %s\n",
2543 system->name);
2544 continue;
2545 }
2546
2547 event_test_stuff();
2548
2549 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
2550 if (WARN_ON_ONCE(ret)) {
2551 pr_warning("error disabling system %s\n",
2552 system->name);
2553 continue;
2554 }
2555
2556 pr_cont("OK\n");
2557 }
2558
2559 /* Test with all events enabled */
2560
2561 pr_info("Running tests on all trace events:\n");
2562 pr_info("Testing all events: ");
2563
2564 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
2565 if (WARN_ON_ONCE(ret)) {
2566 pr_warning("error enabling all events\n");
2567 return;
2568 }
2569
2570 event_test_stuff();
2571
2572 /* reset sysname */
2573 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
2574 if (WARN_ON_ONCE(ret)) {
2575 pr_warning("error disabling all events\n");
2576 return;
2577 }
2578
2579 pr_cont("OK\n");
2580 }
2581
2582 #ifdef CONFIG_FUNCTION_TRACER
2583
2584 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
2585
2586 static void
2587 function_test_events_call(unsigned long ip, unsigned long parent_ip,
2588 struct ftrace_ops *op, struct pt_regs *pt_regs)
2589 {
2590 struct ring_buffer_event *event;
2591 struct ring_buffer *buffer;
2592 struct ftrace_entry *entry;
2593 unsigned long flags;
2594 long disabled;
2595 int cpu;
2596 int pc;
2597
2598 pc = preempt_count();
2599 preempt_disable_notrace();
2600 cpu = raw_smp_processor_id();
2601 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
2602
2603 if (disabled != 1)
2604 goto out;
2605
2606 local_save_flags(flags);
2607
2608 event = trace_current_buffer_lock_reserve(&buffer,
2609 TRACE_FN, sizeof(*entry),
2610 flags, pc);
2611 if (!event)
2612 goto out;
2613 entry = ring_buffer_event_data(event);
2614 entry->ip = ip;
2615 entry->parent_ip = parent_ip;
2616
2617 trace_buffer_unlock_commit(buffer, event, flags, pc);
2618
2619 out:
2620 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
2621 preempt_enable_notrace();
2622 }
2623
2624 static struct ftrace_ops trace_ops __initdata =
2625 {
2626 .func = function_test_events_call,
2627 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
2628 };
2629
2630 static __init void event_trace_self_test_with_function(void)
2631 {
2632 int ret;
2633 ret = register_ftrace_function(&trace_ops);
2634 if (WARN_ON(ret < 0)) {
2635 pr_info("Failed to enable function tracer for event tests\n");
2636 return;
2637 }
2638 pr_info("Running tests again, along with the function tracer\n");
2639 event_trace_self_tests();
2640 unregister_ftrace_function(&trace_ops);
2641 }
2642 #else
2643 static __init void event_trace_self_test_with_function(void)
2644 {
2645 }
2646 #endif
2647
2648 static __init int event_trace_self_tests_init(void)
2649 {
2650 if (!tracing_selftest_disabled) {
2651 event_trace_self_tests();
2652 event_trace_self_test_with_function();
2653 }
2654
2655 return 0;
2656 }
2657
2658 late_initcall(event_trace_self_tests_init);
2659
2660 #endif
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