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Merge remote-tracking branches 'spi/fix/doc', 'spi/fix/nuc900' and 'spi/fix/rspi...
[deliverable/linux.git] / kernel / trace / trace_events.c
1 /*
2 * event tracer
3 *
4 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
5 *
6 * - Added format output of fields of the trace point.
7 * This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
8 *
9 */
10
11 #include <linux/workqueue.h>
12 #include <linux/spinlock.h>
13 #include <linux/kthread.h>
14 #include <linux/debugfs.h>
15 #include <linux/uaccess.h>
16 #include <linux/module.h>
17 #include <linux/ctype.h>
18 #include <linux/slab.h>
19 #include <linux/delay.h>
20
21 #include <asm/setup.h>
22
23 #include "trace_output.h"
24
25 #undef TRACE_SYSTEM
26 #define TRACE_SYSTEM "TRACE_SYSTEM"
27
28 DEFINE_MUTEX(event_mutex);
29
30 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 int trace_event_enable_disable(struct ftrace_event_file *file,
346 int enable, int soft_disable)
347 {
348 return __ftrace_event_enable_disable(file, enable, soft_disable);
349 }
350
351 static int ftrace_event_enable_disable(struct ftrace_event_file *file,
352 int enable)
353 {
354 return __ftrace_event_enable_disable(file, enable, 0);
355 }
356
357 static void ftrace_clear_events(struct trace_array *tr)
358 {
359 struct ftrace_event_file *file;
360
361 mutex_lock(&event_mutex);
362 list_for_each_entry(file, &tr->events, list) {
363 ftrace_event_enable_disable(file, 0);
364 }
365 mutex_unlock(&event_mutex);
366 }
367
368 static void __put_system(struct event_subsystem *system)
369 {
370 struct event_filter *filter = system->filter;
371
372 WARN_ON_ONCE(system_refcount(system) == 0);
373 if (system_refcount_dec(system))
374 return;
375
376 list_del(&system->list);
377
378 if (filter) {
379 kfree(filter->filter_string);
380 kfree(filter);
381 }
382 if (system->ref_count & SYSTEM_FL_FREE_NAME)
383 kfree(system->name);
384 kfree(system);
385 }
386
387 static void __get_system(struct event_subsystem *system)
388 {
389 WARN_ON_ONCE(system_refcount(system) == 0);
390 system_refcount_inc(system);
391 }
392
393 static void __get_system_dir(struct ftrace_subsystem_dir *dir)
394 {
395 WARN_ON_ONCE(dir->ref_count == 0);
396 dir->ref_count++;
397 __get_system(dir->subsystem);
398 }
399
400 static void __put_system_dir(struct ftrace_subsystem_dir *dir)
401 {
402 WARN_ON_ONCE(dir->ref_count == 0);
403 /* If the subsystem is about to be freed, the dir must be too */
404 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
405
406 __put_system(dir->subsystem);
407 if (!--dir->ref_count)
408 kfree(dir);
409 }
410
411 static void put_system(struct ftrace_subsystem_dir *dir)
412 {
413 mutex_lock(&event_mutex);
414 __put_system_dir(dir);
415 mutex_unlock(&event_mutex);
416 }
417
418 static void remove_subsystem(struct ftrace_subsystem_dir *dir)
419 {
420 if (!dir)
421 return;
422
423 if (!--dir->nr_events) {
424 debugfs_remove_recursive(dir->entry);
425 list_del(&dir->list);
426 __put_system_dir(dir);
427 }
428 }
429
430 static void remove_event_file_dir(struct ftrace_event_file *file)
431 {
432 struct dentry *dir = file->dir;
433 struct dentry *child;
434
435 if (dir) {
436 spin_lock(&dir->d_lock); /* probably unneeded */
437 list_for_each_entry(child, &dir->d_subdirs, d_u.d_child) {
438 if (child->d_inode) /* probably unneeded */
439 child->d_inode->i_private = NULL;
440 }
441 spin_unlock(&dir->d_lock);
442
443 debugfs_remove_recursive(dir);
444 }
445
446 list_del(&file->list);
447 remove_subsystem(file->system);
448 kmem_cache_free(file_cachep, file);
449 }
450
451 /*
452 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
453 */
454 static int
455 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
456 const char *sub, const char *event, int set)
457 {
458 struct ftrace_event_file *file;
459 struct ftrace_event_call *call;
460 int ret = -EINVAL;
461
462 list_for_each_entry(file, &tr->events, list) {
463
464 call = file->event_call;
465
466 if (!call->name || !call->class || !call->class->reg)
467 continue;
468
469 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
470 continue;
471
472 if (match &&
473 strcmp(match, call->name) != 0 &&
474 strcmp(match, call->class->system) != 0)
475 continue;
476
477 if (sub && strcmp(sub, call->class->system) != 0)
478 continue;
479
480 if (event && strcmp(event, call->name) != 0)
481 continue;
482
483 ftrace_event_enable_disable(file, set);
484
485 ret = 0;
486 }
487
488 return ret;
489 }
490
491 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
492 const char *sub, const char *event, int set)
493 {
494 int ret;
495
496 mutex_lock(&event_mutex);
497 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
498 mutex_unlock(&event_mutex);
499
500 return ret;
501 }
502
503 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
504 {
505 char *event = NULL, *sub = NULL, *match;
506
507 /*
508 * The buf format can be <subsystem>:<event-name>
509 * *:<event-name> means any event by that name.
510 * :<event-name> is the same.
511 *
512 * <subsystem>:* means all events in that subsystem
513 * <subsystem>: means the same.
514 *
515 * <name> (no ':') means all events in a subsystem with
516 * the name <name> or any event that matches <name>
517 */
518
519 match = strsep(&buf, ":");
520 if (buf) {
521 sub = match;
522 event = buf;
523 match = NULL;
524
525 if (!strlen(sub) || strcmp(sub, "*") == 0)
526 sub = NULL;
527 if (!strlen(event) || strcmp(event, "*") == 0)
528 event = NULL;
529 }
530
531 return __ftrace_set_clr_event(tr, match, sub, event, set);
532 }
533
534 /**
535 * trace_set_clr_event - enable or disable an event
536 * @system: system name to match (NULL for any system)
537 * @event: event name to match (NULL for all events, within system)
538 * @set: 1 to enable, 0 to disable
539 *
540 * This is a way for other parts of the kernel to enable or disable
541 * event recording.
542 *
543 * Returns 0 on success, -EINVAL if the parameters do not match any
544 * registered events.
545 */
546 int trace_set_clr_event(const char *system, const char *event, int set)
547 {
548 struct trace_array *tr = top_trace_array();
549
550 return __ftrace_set_clr_event(tr, NULL, system, event, set);
551 }
552 EXPORT_SYMBOL_GPL(trace_set_clr_event);
553
554 /* 128 should be much more than enough */
555 #define EVENT_BUF_SIZE 127
556
557 static ssize_t
558 ftrace_event_write(struct file *file, const char __user *ubuf,
559 size_t cnt, loff_t *ppos)
560 {
561 struct trace_parser parser;
562 struct seq_file *m = file->private_data;
563 struct trace_array *tr = m->private;
564 ssize_t read, ret;
565
566 if (!cnt)
567 return 0;
568
569 ret = tracing_update_buffers();
570 if (ret < 0)
571 return ret;
572
573 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
574 return -ENOMEM;
575
576 read = trace_get_user(&parser, ubuf, cnt, ppos);
577
578 if (read >= 0 && trace_parser_loaded((&parser))) {
579 int set = 1;
580
581 if (*parser.buffer == '!')
582 set = 0;
583
584 parser.buffer[parser.idx] = 0;
585
586 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
587 if (ret)
588 goto out_put;
589 }
590
591 ret = read;
592
593 out_put:
594 trace_parser_put(&parser);
595
596 return ret;
597 }
598
599 static void *
600 t_next(struct seq_file *m, void *v, loff_t *pos)
601 {
602 struct ftrace_event_file *file = v;
603 struct ftrace_event_call *call;
604 struct trace_array *tr = m->private;
605
606 (*pos)++;
607
608 list_for_each_entry_continue(file, &tr->events, list) {
609 call = file->event_call;
610 /*
611 * The ftrace subsystem is for showing formats only.
612 * They can not be enabled or disabled via the event files.
613 */
614 if (call->class && call->class->reg)
615 return file;
616 }
617
618 return NULL;
619 }
620
621 static void *t_start(struct seq_file *m, loff_t *pos)
622 {
623 struct ftrace_event_file *file;
624 struct trace_array *tr = m->private;
625 loff_t l;
626
627 mutex_lock(&event_mutex);
628
629 file = list_entry(&tr->events, struct ftrace_event_file, list);
630 for (l = 0; l <= *pos; ) {
631 file = t_next(m, file, &l);
632 if (!file)
633 break;
634 }
635 return file;
636 }
637
638 static void *
639 s_next(struct seq_file *m, void *v, loff_t *pos)
640 {
641 struct ftrace_event_file *file = v;
642 struct trace_array *tr = m->private;
643
644 (*pos)++;
645
646 list_for_each_entry_continue(file, &tr->events, list) {
647 if (file->flags & FTRACE_EVENT_FL_ENABLED)
648 return file;
649 }
650
651 return NULL;
652 }
653
654 static void *s_start(struct seq_file *m, loff_t *pos)
655 {
656 struct ftrace_event_file *file;
657 struct trace_array *tr = m->private;
658 loff_t l;
659
660 mutex_lock(&event_mutex);
661
662 file = list_entry(&tr->events, struct ftrace_event_file, list);
663 for (l = 0; l <= *pos; ) {
664 file = s_next(m, file, &l);
665 if (!file)
666 break;
667 }
668 return file;
669 }
670
671 static int t_show(struct seq_file *m, void *v)
672 {
673 struct ftrace_event_file *file = v;
674 struct ftrace_event_call *call = file->event_call;
675
676 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
677 seq_printf(m, "%s:", call->class->system);
678 seq_printf(m, "%s\n", call->name);
679
680 return 0;
681 }
682
683 static void t_stop(struct seq_file *m, void *p)
684 {
685 mutex_unlock(&event_mutex);
686 }
687
688 static ssize_t
689 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
690 loff_t *ppos)
691 {
692 struct ftrace_event_file *file;
693 unsigned long flags;
694 char buf[4] = "0";
695
696 mutex_lock(&event_mutex);
697 file = event_file_data(filp);
698 if (likely(file))
699 flags = file->flags;
700 mutex_unlock(&event_mutex);
701
702 if (!file)
703 return -ENODEV;
704
705 if (flags & FTRACE_EVENT_FL_ENABLED &&
706 !(flags & FTRACE_EVENT_FL_SOFT_DISABLED))
707 strcpy(buf, "1");
708
709 if (flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
710 flags & FTRACE_EVENT_FL_SOFT_MODE)
711 strcat(buf, "*");
712
713 strcat(buf, "\n");
714
715 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
716 }
717
718 static ssize_t
719 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
720 loff_t *ppos)
721 {
722 struct ftrace_event_file *file;
723 unsigned long val;
724 int ret;
725
726 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
727 if (ret)
728 return ret;
729
730 ret = tracing_update_buffers();
731 if (ret < 0)
732 return ret;
733
734 switch (val) {
735 case 0:
736 case 1:
737 ret = -ENODEV;
738 mutex_lock(&event_mutex);
739 file = event_file_data(filp);
740 if (likely(file))
741 ret = ftrace_event_enable_disable(file, val);
742 mutex_unlock(&event_mutex);
743 break;
744
745 default:
746 return -EINVAL;
747 }
748
749 *ppos += cnt;
750
751 return ret ? ret : cnt;
752 }
753
754 static ssize_t
755 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
756 loff_t *ppos)
757 {
758 const char set_to_char[4] = { '?', '0', '1', 'X' };
759 struct ftrace_subsystem_dir *dir = filp->private_data;
760 struct event_subsystem *system = dir->subsystem;
761 struct ftrace_event_call *call;
762 struct ftrace_event_file *file;
763 struct trace_array *tr = dir->tr;
764 char buf[2];
765 int set = 0;
766 int ret;
767
768 mutex_lock(&event_mutex);
769 list_for_each_entry(file, &tr->events, list) {
770 call = file->event_call;
771 if (!call->name || !call->class || !call->class->reg)
772 continue;
773
774 if (system && strcmp(call->class->system, system->name) != 0)
775 continue;
776
777 /*
778 * We need to find out if all the events are set
779 * or if all events or cleared, or if we have
780 * a mixture.
781 */
782 set |= (1 << !!(file->flags & FTRACE_EVENT_FL_ENABLED));
783
784 /*
785 * If we have a mixture, no need to look further.
786 */
787 if (set == 3)
788 break;
789 }
790 mutex_unlock(&event_mutex);
791
792 buf[0] = set_to_char[set];
793 buf[1] = '\n';
794
795 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
796
797 return ret;
798 }
799
800 static ssize_t
801 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
802 loff_t *ppos)
803 {
804 struct ftrace_subsystem_dir *dir = filp->private_data;
805 struct event_subsystem *system = dir->subsystem;
806 const char *name = NULL;
807 unsigned long val;
808 ssize_t ret;
809
810 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
811 if (ret)
812 return ret;
813
814 ret = tracing_update_buffers();
815 if (ret < 0)
816 return ret;
817
818 if (val != 0 && val != 1)
819 return -EINVAL;
820
821 /*
822 * Opening of "enable" adds a ref count to system,
823 * so the name is safe to use.
824 */
825 if (system)
826 name = system->name;
827
828 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
829 if (ret)
830 goto out;
831
832 ret = cnt;
833
834 out:
835 *ppos += cnt;
836
837 return ret;
838 }
839
840 enum {
841 FORMAT_HEADER = 1,
842 FORMAT_FIELD_SEPERATOR = 2,
843 FORMAT_PRINTFMT = 3,
844 };
845
846 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
847 {
848 struct ftrace_event_call *call = event_file_data(m->private);
849 struct list_head *common_head = &ftrace_common_fields;
850 struct list_head *head = trace_get_fields(call);
851 struct list_head *node = v;
852
853 (*pos)++;
854
855 switch ((unsigned long)v) {
856 case FORMAT_HEADER:
857 node = common_head;
858 break;
859
860 case FORMAT_FIELD_SEPERATOR:
861 node = head;
862 break;
863
864 case FORMAT_PRINTFMT:
865 /* all done */
866 return NULL;
867 }
868
869 node = node->prev;
870 if (node == common_head)
871 return (void *)FORMAT_FIELD_SEPERATOR;
872 else if (node == head)
873 return (void *)FORMAT_PRINTFMT;
874 else
875 return node;
876 }
877
878 static int f_show(struct seq_file *m, void *v)
879 {
880 struct ftrace_event_call *call = event_file_data(m->private);
881 struct ftrace_event_field *field;
882 const char *array_descriptor;
883
884 switch ((unsigned long)v) {
885 case FORMAT_HEADER:
886 seq_printf(m, "name: %s\n", call->name);
887 seq_printf(m, "ID: %d\n", call->event.type);
888 seq_printf(m, "format:\n");
889 return 0;
890
891 case FORMAT_FIELD_SEPERATOR:
892 seq_putc(m, '\n');
893 return 0;
894
895 case FORMAT_PRINTFMT:
896 seq_printf(m, "\nprint fmt: %s\n",
897 call->print_fmt);
898 return 0;
899 }
900
901 field = list_entry(v, struct ftrace_event_field, link);
902 /*
903 * Smartly shows the array type(except dynamic array).
904 * Normal:
905 * field:TYPE VAR
906 * If TYPE := TYPE[LEN], it is shown:
907 * field:TYPE VAR[LEN]
908 */
909 array_descriptor = strchr(field->type, '[');
910
911 if (!strncmp(field->type, "__data_loc", 10))
912 array_descriptor = NULL;
913
914 if (!array_descriptor)
915 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
916 field->type, field->name, field->offset,
917 field->size, !!field->is_signed);
918 else
919 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
920 (int)(array_descriptor - field->type),
921 field->type, field->name,
922 array_descriptor, field->offset,
923 field->size, !!field->is_signed);
924
925 return 0;
926 }
927
928 static void *f_start(struct seq_file *m, loff_t *pos)
929 {
930 void *p = (void *)FORMAT_HEADER;
931 loff_t l = 0;
932
933 /* ->stop() is called even if ->start() fails */
934 mutex_lock(&event_mutex);
935 if (!event_file_data(m->private))
936 return ERR_PTR(-ENODEV);
937
938 while (l < *pos && p)
939 p = f_next(m, p, &l);
940
941 return p;
942 }
943
944 static void f_stop(struct seq_file *m, void *p)
945 {
946 mutex_unlock(&event_mutex);
947 }
948
949 static const struct seq_operations trace_format_seq_ops = {
950 .start = f_start,
951 .next = f_next,
952 .stop = f_stop,
953 .show = f_show,
954 };
955
956 static int trace_format_open(struct inode *inode, struct file *file)
957 {
958 struct seq_file *m;
959 int ret;
960
961 ret = seq_open(file, &trace_format_seq_ops);
962 if (ret < 0)
963 return ret;
964
965 m = file->private_data;
966 m->private = file;
967
968 return 0;
969 }
970
971 static ssize_t
972 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
973 {
974 int id = (long)event_file_data(filp);
975 char buf[32];
976 int len;
977
978 if (*ppos)
979 return 0;
980
981 if (unlikely(!id))
982 return -ENODEV;
983
984 len = sprintf(buf, "%d\n", id);
985
986 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
987 }
988
989 static ssize_t
990 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
991 loff_t *ppos)
992 {
993 struct ftrace_event_file *file;
994 struct trace_seq *s;
995 int r = -ENODEV;
996
997 if (*ppos)
998 return 0;
999
1000 s = kmalloc(sizeof(*s), GFP_KERNEL);
1001
1002 if (!s)
1003 return -ENOMEM;
1004
1005 trace_seq_init(s);
1006
1007 mutex_lock(&event_mutex);
1008 file = event_file_data(filp);
1009 if (file)
1010 print_event_filter(file, s);
1011 mutex_unlock(&event_mutex);
1012
1013 if (file)
1014 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1015
1016 kfree(s);
1017
1018 return r;
1019 }
1020
1021 static ssize_t
1022 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1023 loff_t *ppos)
1024 {
1025 struct ftrace_event_file *file;
1026 char *buf;
1027 int err = -ENODEV;
1028
1029 if (cnt >= PAGE_SIZE)
1030 return -EINVAL;
1031
1032 buf = (char *)__get_free_page(GFP_TEMPORARY);
1033 if (!buf)
1034 return -ENOMEM;
1035
1036 if (copy_from_user(buf, ubuf, cnt)) {
1037 free_page((unsigned long) buf);
1038 return -EFAULT;
1039 }
1040 buf[cnt] = '\0';
1041
1042 mutex_lock(&event_mutex);
1043 file = event_file_data(filp);
1044 if (file)
1045 err = apply_event_filter(file, buf);
1046 mutex_unlock(&event_mutex);
1047
1048 free_page((unsigned long) buf);
1049 if (err < 0)
1050 return err;
1051
1052 *ppos += cnt;
1053
1054 return cnt;
1055 }
1056
1057 static LIST_HEAD(event_subsystems);
1058
1059 static int subsystem_open(struct inode *inode, struct file *filp)
1060 {
1061 struct event_subsystem *system = NULL;
1062 struct ftrace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1063 struct trace_array *tr;
1064 int ret;
1065
1066 if (tracing_is_disabled())
1067 return -ENODEV;
1068
1069 /* Make sure the system still exists */
1070 mutex_lock(&trace_types_lock);
1071 mutex_lock(&event_mutex);
1072 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1073 list_for_each_entry(dir, &tr->systems, list) {
1074 if (dir == inode->i_private) {
1075 /* Don't open systems with no events */
1076 if (dir->nr_events) {
1077 __get_system_dir(dir);
1078 system = dir->subsystem;
1079 }
1080 goto exit_loop;
1081 }
1082 }
1083 }
1084 exit_loop:
1085 mutex_unlock(&event_mutex);
1086 mutex_unlock(&trace_types_lock);
1087
1088 if (!system)
1089 return -ENODEV;
1090
1091 /* Some versions of gcc think dir can be uninitialized here */
1092 WARN_ON(!dir);
1093
1094 /* Still need to increment the ref count of the system */
1095 if (trace_array_get(tr) < 0) {
1096 put_system(dir);
1097 return -ENODEV;
1098 }
1099
1100 ret = tracing_open_generic(inode, filp);
1101 if (ret < 0) {
1102 trace_array_put(tr);
1103 put_system(dir);
1104 }
1105
1106 return ret;
1107 }
1108
1109 static int system_tr_open(struct inode *inode, struct file *filp)
1110 {
1111 struct ftrace_subsystem_dir *dir;
1112 struct trace_array *tr = inode->i_private;
1113 int ret;
1114
1115 if (tracing_is_disabled())
1116 return -ENODEV;
1117
1118 if (trace_array_get(tr) < 0)
1119 return -ENODEV;
1120
1121 /* Make a temporary dir that has no system but points to tr */
1122 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1123 if (!dir) {
1124 trace_array_put(tr);
1125 return -ENOMEM;
1126 }
1127
1128 dir->tr = tr;
1129
1130 ret = tracing_open_generic(inode, filp);
1131 if (ret < 0) {
1132 trace_array_put(tr);
1133 kfree(dir);
1134 return ret;
1135 }
1136
1137 filp->private_data = dir;
1138
1139 return 0;
1140 }
1141
1142 static int subsystem_release(struct inode *inode, struct file *file)
1143 {
1144 struct ftrace_subsystem_dir *dir = file->private_data;
1145
1146 trace_array_put(dir->tr);
1147
1148 /*
1149 * If dir->subsystem is NULL, then this is a temporary
1150 * descriptor that was made for a trace_array to enable
1151 * all subsystems.
1152 */
1153 if (dir->subsystem)
1154 put_system(dir);
1155 else
1156 kfree(dir);
1157
1158 return 0;
1159 }
1160
1161 static ssize_t
1162 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1163 loff_t *ppos)
1164 {
1165 struct ftrace_subsystem_dir *dir = filp->private_data;
1166 struct event_subsystem *system = dir->subsystem;
1167 struct trace_seq *s;
1168 int r;
1169
1170 if (*ppos)
1171 return 0;
1172
1173 s = kmalloc(sizeof(*s), GFP_KERNEL);
1174 if (!s)
1175 return -ENOMEM;
1176
1177 trace_seq_init(s);
1178
1179 print_subsystem_event_filter(system, s);
1180 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1181
1182 kfree(s);
1183
1184 return r;
1185 }
1186
1187 static ssize_t
1188 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1189 loff_t *ppos)
1190 {
1191 struct ftrace_subsystem_dir *dir = filp->private_data;
1192 char *buf;
1193 int err;
1194
1195 if (cnt >= PAGE_SIZE)
1196 return -EINVAL;
1197
1198 buf = (char *)__get_free_page(GFP_TEMPORARY);
1199 if (!buf)
1200 return -ENOMEM;
1201
1202 if (copy_from_user(buf, ubuf, cnt)) {
1203 free_page((unsigned long) buf);
1204 return -EFAULT;
1205 }
1206 buf[cnt] = '\0';
1207
1208 err = apply_subsystem_event_filter(dir, buf);
1209 free_page((unsigned long) buf);
1210 if (err < 0)
1211 return err;
1212
1213 *ppos += cnt;
1214
1215 return cnt;
1216 }
1217
1218 static ssize_t
1219 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1220 {
1221 int (*func)(struct trace_seq *s) = filp->private_data;
1222 struct trace_seq *s;
1223 int r;
1224
1225 if (*ppos)
1226 return 0;
1227
1228 s = kmalloc(sizeof(*s), GFP_KERNEL);
1229 if (!s)
1230 return -ENOMEM;
1231
1232 trace_seq_init(s);
1233
1234 func(s);
1235 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1236
1237 kfree(s);
1238
1239 return r;
1240 }
1241
1242 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1243 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1244 static int ftrace_event_release(struct inode *inode, struct file *file);
1245
1246 static const struct seq_operations show_event_seq_ops = {
1247 .start = t_start,
1248 .next = t_next,
1249 .show = t_show,
1250 .stop = t_stop,
1251 };
1252
1253 static const struct seq_operations show_set_event_seq_ops = {
1254 .start = s_start,
1255 .next = s_next,
1256 .show = t_show,
1257 .stop = t_stop,
1258 };
1259
1260 static const struct file_operations ftrace_avail_fops = {
1261 .open = ftrace_event_avail_open,
1262 .read = seq_read,
1263 .llseek = seq_lseek,
1264 .release = seq_release,
1265 };
1266
1267 static const struct file_operations ftrace_set_event_fops = {
1268 .open = ftrace_event_set_open,
1269 .read = seq_read,
1270 .write = ftrace_event_write,
1271 .llseek = seq_lseek,
1272 .release = ftrace_event_release,
1273 };
1274
1275 static const struct file_operations ftrace_enable_fops = {
1276 .open = tracing_open_generic,
1277 .read = event_enable_read,
1278 .write = event_enable_write,
1279 .llseek = default_llseek,
1280 };
1281
1282 static const struct file_operations ftrace_event_format_fops = {
1283 .open = trace_format_open,
1284 .read = seq_read,
1285 .llseek = seq_lseek,
1286 .release = seq_release,
1287 };
1288
1289 static const struct file_operations ftrace_event_id_fops = {
1290 .read = event_id_read,
1291 .llseek = default_llseek,
1292 };
1293
1294 static const struct file_operations ftrace_event_filter_fops = {
1295 .open = tracing_open_generic,
1296 .read = event_filter_read,
1297 .write = event_filter_write,
1298 .llseek = default_llseek,
1299 };
1300
1301 static const struct file_operations ftrace_subsystem_filter_fops = {
1302 .open = subsystem_open,
1303 .read = subsystem_filter_read,
1304 .write = subsystem_filter_write,
1305 .llseek = default_llseek,
1306 .release = subsystem_release,
1307 };
1308
1309 static const struct file_operations ftrace_system_enable_fops = {
1310 .open = subsystem_open,
1311 .read = system_enable_read,
1312 .write = system_enable_write,
1313 .llseek = default_llseek,
1314 .release = subsystem_release,
1315 };
1316
1317 static const struct file_operations ftrace_tr_enable_fops = {
1318 .open = system_tr_open,
1319 .read = system_enable_read,
1320 .write = system_enable_write,
1321 .llseek = default_llseek,
1322 .release = subsystem_release,
1323 };
1324
1325 static const struct file_operations ftrace_show_header_fops = {
1326 .open = tracing_open_generic,
1327 .read = show_header,
1328 .llseek = default_llseek,
1329 };
1330
1331 static int
1332 ftrace_event_open(struct inode *inode, struct file *file,
1333 const struct seq_operations *seq_ops)
1334 {
1335 struct seq_file *m;
1336 int ret;
1337
1338 ret = seq_open(file, seq_ops);
1339 if (ret < 0)
1340 return ret;
1341 m = file->private_data;
1342 /* copy tr over to seq ops */
1343 m->private = inode->i_private;
1344
1345 return ret;
1346 }
1347
1348 static int ftrace_event_release(struct inode *inode, struct file *file)
1349 {
1350 struct trace_array *tr = inode->i_private;
1351
1352 trace_array_put(tr);
1353
1354 return seq_release(inode, file);
1355 }
1356
1357 static int
1358 ftrace_event_avail_open(struct inode *inode, struct file *file)
1359 {
1360 const struct seq_operations *seq_ops = &show_event_seq_ops;
1361
1362 return ftrace_event_open(inode, file, seq_ops);
1363 }
1364
1365 static int
1366 ftrace_event_set_open(struct inode *inode, struct file *file)
1367 {
1368 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1369 struct trace_array *tr = inode->i_private;
1370 int ret;
1371
1372 if (trace_array_get(tr) < 0)
1373 return -ENODEV;
1374
1375 if ((file->f_mode & FMODE_WRITE) &&
1376 (file->f_flags & O_TRUNC))
1377 ftrace_clear_events(tr);
1378
1379 ret = ftrace_event_open(inode, file, seq_ops);
1380 if (ret < 0)
1381 trace_array_put(tr);
1382 return ret;
1383 }
1384
1385 static struct event_subsystem *
1386 create_new_subsystem(const char *name)
1387 {
1388 struct event_subsystem *system;
1389
1390 /* need to create new entry */
1391 system = kmalloc(sizeof(*system), GFP_KERNEL);
1392 if (!system)
1393 return NULL;
1394
1395 system->ref_count = 1;
1396
1397 /* Only allocate if dynamic (kprobes and modules) */
1398 if (!core_kernel_data((unsigned long)name)) {
1399 system->ref_count |= SYSTEM_FL_FREE_NAME;
1400 system->name = kstrdup(name, GFP_KERNEL);
1401 if (!system->name)
1402 goto out_free;
1403 } else
1404 system->name = name;
1405
1406 system->filter = NULL;
1407
1408 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1409 if (!system->filter)
1410 goto out_free;
1411
1412 list_add(&system->list, &event_subsystems);
1413
1414 return system;
1415
1416 out_free:
1417 if (system->ref_count & SYSTEM_FL_FREE_NAME)
1418 kfree(system->name);
1419 kfree(system);
1420 return NULL;
1421 }
1422
1423 static struct dentry *
1424 event_subsystem_dir(struct trace_array *tr, const char *name,
1425 struct ftrace_event_file *file, struct dentry *parent)
1426 {
1427 struct ftrace_subsystem_dir *dir;
1428 struct event_subsystem *system;
1429 struct dentry *entry;
1430
1431 /* First see if we did not already create this dir */
1432 list_for_each_entry(dir, &tr->systems, list) {
1433 system = dir->subsystem;
1434 if (strcmp(system->name, name) == 0) {
1435 dir->nr_events++;
1436 file->system = dir;
1437 return dir->entry;
1438 }
1439 }
1440
1441 /* Now see if the system itself exists. */
1442 list_for_each_entry(system, &event_subsystems, list) {
1443 if (strcmp(system->name, name) == 0)
1444 break;
1445 }
1446 /* Reset system variable when not found */
1447 if (&system->list == &event_subsystems)
1448 system = NULL;
1449
1450 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1451 if (!dir)
1452 goto out_fail;
1453
1454 if (!system) {
1455 system = create_new_subsystem(name);
1456 if (!system)
1457 goto out_free;
1458 } else
1459 __get_system(system);
1460
1461 dir->entry = debugfs_create_dir(name, parent);
1462 if (!dir->entry) {
1463 pr_warning("Failed to create system directory %s\n", name);
1464 __put_system(system);
1465 goto out_free;
1466 }
1467
1468 dir->tr = tr;
1469 dir->ref_count = 1;
1470 dir->nr_events = 1;
1471 dir->subsystem = system;
1472 file->system = dir;
1473
1474 entry = debugfs_create_file("filter", 0644, dir->entry, dir,
1475 &ftrace_subsystem_filter_fops);
1476 if (!entry) {
1477 kfree(system->filter);
1478 system->filter = NULL;
1479 pr_warning("Could not create debugfs '%s/filter' entry\n", name);
1480 }
1481
1482 trace_create_file("enable", 0644, dir->entry, dir,
1483 &ftrace_system_enable_fops);
1484
1485 list_add(&dir->list, &tr->systems);
1486
1487 return dir->entry;
1488
1489 out_free:
1490 kfree(dir);
1491 out_fail:
1492 /* Only print this message if failed on memory allocation */
1493 if (!dir || !system)
1494 pr_warning("No memory to create event subsystem %s\n",
1495 name);
1496 return NULL;
1497 }
1498
1499 static int
1500 event_create_dir(struct dentry *parent, struct ftrace_event_file *file)
1501 {
1502 struct ftrace_event_call *call = file->event_call;
1503 struct trace_array *tr = file->tr;
1504 struct list_head *head;
1505 struct dentry *d_events;
1506 int ret;
1507
1508 /*
1509 * If the trace point header did not define TRACE_SYSTEM
1510 * then the system would be called "TRACE_SYSTEM".
1511 */
1512 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1513 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1514 if (!d_events)
1515 return -ENOMEM;
1516 } else
1517 d_events = parent;
1518
1519 file->dir = debugfs_create_dir(call->name, d_events);
1520 if (!file->dir) {
1521 pr_warning("Could not create debugfs '%s' directory\n",
1522 call->name);
1523 return -1;
1524 }
1525
1526 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1527 trace_create_file("enable", 0644, file->dir, file,
1528 &ftrace_enable_fops);
1529
1530 #ifdef CONFIG_PERF_EVENTS
1531 if (call->event.type && call->class->reg)
1532 trace_create_file("id", 0444, file->dir,
1533 (void *)(long)call->event.type,
1534 &ftrace_event_id_fops);
1535 #endif
1536
1537 /*
1538 * Other events may have the same class. Only update
1539 * the fields if they are not already defined.
1540 */
1541 head = trace_get_fields(call);
1542 if (list_empty(head)) {
1543 ret = call->class->define_fields(call);
1544 if (ret < 0) {
1545 pr_warning("Could not initialize trace point"
1546 " events/%s\n", call->name);
1547 return -1;
1548 }
1549 }
1550 trace_create_file("filter", 0644, file->dir, file,
1551 &ftrace_event_filter_fops);
1552
1553 trace_create_file("trigger", 0644, file->dir, file,
1554 &event_trigger_fops);
1555
1556 trace_create_file("format", 0444, file->dir, call,
1557 &ftrace_event_format_fops);
1558
1559 return 0;
1560 }
1561
1562 static void remove_event_from_tracers(struct ftrace_event_call *call)
1563 {
1564 struct ftrace_event_file *file;
1565 struct trace_array *tr;
1566
1567 do_for_each_event_file_safe(tr, file) {
1568 if (file->event_call != call)
1569 continue;
1570
1571 remove_event_file_dir(file);
1572 /*
1573 * The do_for_each_event_file_safe() is
1574 * a double loop. After finding the call for this
1575 * trace_array, we use break to jump to the next
1576 * trace_array.
1577 */
1578 break;
1579 } while_for_each_event_file();
1580 }
1581
1582 static void event_remove(struct ftrace_event_call *call)
1583 {
1584 struct trace_array *tr;
1585 struct ftrace_event_file *file;
1586
1587 do_for_each_event_file(tr, file) {
1588 if (file->event_call != call)
1589 continue;
1590 ftrace_event_enable_disable(file, 0);
1591 destroy_preds(file);
1592 /*
1593 * The do_for_each_event_file() is
1594 * a double loop. After finding the call for this
1595 * trace_array, we use break to jump to the next
1596 * trace_array.
1597 */
1598 break;
1599 } while_for_each_event_file();
1600
1601 if (call->event.funcs)
1602 __unregister_ftrace_event(&call->event);
1603 remove_event_from_tracers(call);
1604 list_del(&call->list);
1605 }
1606
1607 static int event_init(struct ftrace_event_call *call)
1608 {
1609 int ret = 0;
1610
1611 if (WARN_ON(!call->name))
1612 return -EINVAL;
1613
1614 if (call->class->raw_init) {
1615 ret = call->class->raw_init(call);
1616 if (ret < 0 && ret != -ENOSYS)
1617 pr_warn("Could not initialize trace events/%s\n",
1618 call->name);
1619 }
1620
1621 return ret;
1622 }
1623
1624 static int
1625 __register_event(struct ftrace_event_call *call, struct module *mod)
1626 {
1627 int ret;
1628
1629 ret = event_init(call);
1630 if (ret < 0)
1631 return ret;
1632
1633 list_add(&call->list, &ftrace_events);
1634 call->mod = mod;
1635
1636 return 0;
1637 }
1638
1639 static struct ftrace_event_file *
1640 trace_create_new_event(struct ftrace_event_call *call,
1641 struct trace_array *tr)
1642 {
1643 struct ftrace_event_file *file;
1644
1645 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
1646 if (!file)
1647 return NULL;
1648
1649 file->event_call = call;
1650 file->tr = tr;
1651 atomic_set(&file->sm_ref, 0);
1652 atomic_set(&file->tm_ref, 0);
1653 INIT_LIST_HEAD(&file->triggers);
1654 list_add(&file->list, &tr->events);
1655
1656 return file;
1657 }
1658
1659 /* Add an event to a trace directory */
1660 static int
1661 __trace_add_new_event(struct ftrace_event_call *call, struct trace_array *tr)
1662 {
1663 struct ftrace_event_file *file;
1664
1665 file = trace_create_new_event(call, tr);
1666 if (!file)
1667 return -ENOMEM;
1668
1669 return event_create_dir(tr->event_dir, file);
1670 }
1671
1672 /*
1673 * Just create a decriptor for early init. A descriptor is required
1674 * for enabling events at boot. We want to enable events before
1675 * the filesystem is initialized.
1676 */
1677 static __init int
1678 __trace_early_add_new_event(struct ftrace_event_call *call,
1679 struct trace_array *tr)
1680 {
1681 struct ftrace_event_file *file;
1682
1683 file = trace_create_new_event(call, tr);
1684 if (!file)
1685 return -ENOMEM;
1686
1687 return 0;
1688 }
1689
1690 struct ftrace_module_file_ops;
1691 static void __add_event_to_tracers(struct ftrace_event_call *call);
1692
1693 /* Add an additional event_call dynamically */
1694 int trace_add_event_call(struct ftrace_event_call *call)
1695 {
1696 int ret;
1697 mutex_lock(&trace_types_lock);
1698 mutex_lock(&event_mutex);
1699
1700 ret = __register_event(call, NULL);
1701 if (ret >= 0)
1702 __add_event_to_tracers(call);
1703
1704 mutex_unlock(&event_mutex);
1705 mutex_unlock(&trace_types_lock);
1706 return ret;
1707 }
1708
1709 /*
1710 * Must be called under locking of trace_types_lock, event_mutex and
1711 * trace_event_sem.
1712 */
1713 static void __trace_remove_event_call(struct ftrace_event_call *call)
1714 {
1715 event_remove(call);
1716 trace_destroy_fields(call);
1717 destroy_call_preds(call);
1718 }
1719
1720 static int probe_remove_event_call(struct ftrace_event_call *call)
1721 {
1722 struct trace_array *tr;
1723 struct ftrace_event_file *file;
1724
1725 #ifdef CONFIG_PERF_EVENTS
1726 if (call->perf_refcount)
1727 return -EBUSY;
1728 #endif
1729 do_for_each_event_file(tr, file) {
1730 if (file->event_call != call)
1731 continue;
1732 /*
1733 * We can't rely on ftrace_event_enable_disable(enable => 0)
1734 * we are going to do, FTRACE_EVENT_FL_SOFT_MODE can suppress
1735 * TRACE_REG_UNREGISTER.
1736 */
1737 if (file->flags & FTRACE_EVENT_FL_ENABLED)
1738 return -EBUSY;
1739 /*
1740 * The do_for_each_event_file_safe() is
1741 * a double loop. After finding the call for this
1742 * trace_array, we use break to jump to the next
1743 * trace_array.
1744 */
1745 break;
1746 } while_for_each_event_file();
1747
1748 __trace_remove_event_call(call);
1749
1750 return 0;
1751 }
1752
1753 /* Remove an event_call */
1754 int trace_remove_event_call(struct ftrace_event_call *call)
1755 {
1756 int ret;
1757
1758 mutex_lock(&trace_types_lock);
1759 mutex_lock(&event_mutex);
1760 down_write(&trace_event_sem);
1761 ret = probe_remove_event_call(call);
1762 up_write(&trace_event_sem);
1763 mutex_unlock(&event_mutex);
1764 mutex_unlock(&trace_types_lock);
1765
1766 return ret;
1767 }
1768
1769 #define for_each_event(event, start, end) \
1770 for (event = start; \
1771 (unsigned long)event < (unsigned long)end; \
1772 event++)
1773
1774 #ifdef CONFIG_MODULES
1775
1776 static void trace_module_add_events(struct module *mod)
1777 {
1778 struct ftrace_event_call **call, **start, **end;
1779
1780 start = mod->trace_events;
1781 end = mod->trace_events + mod->num_trace_events;
1782
1783 for_each_event(call, start, end) {
1784 __register_event(*call, mod);
1785 __add_event_to_tracers(*call);
1786 }
1787 }
1788
1789 static void trace_module_remove_events(struct module *mod)
1790 {
1791 struct ftrace_event_call *call, *p;
1792 bool clear_trace = false;
1793
1794 down_write(&trace_event_sem);
1795 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1796 if (call->mod == mod) {
1797 if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
1798 clear_trace = true;
1799 __trace_remove_event_call(call);
1800 }
1801 }
1802 up_write(&trace_event_sem);
1803
1804 /*
1805 * It is safest to reset the ring buffer if the module being unloaded
1806 * registered any events that were used. The only worry is if
1807 * a new module gets loaded, and takes on the same id as the events
1808 * of this module. When printing out the buffer, traced events left
1809 * over from this module may be passed to the new module events and
1810 * unexpected results may occur.
1811 */
1812 if (clear_trace)
1813 tracing_reset_all_online_cpus();
1814 }
1815
1816 static int trace_module_notify(struct notifier_block *self,
1817 unsigned long val, void *data)
1818 {
1819 struct module *mod = data;
1820
1821 mutex_lock(&trace_types_lock);
1822 mutex_lock(&event_mutex);
1823 switch (val) {
1824 case MODULE_STATE_COMING:
1825 trace_module_add_events(mod);
1826 break;
1827 case MODULE_STATE_GOING:
1828 trace_module_remove_events(mod);
1829 break;
1830 }
1831 mutex_unlock(&event_mutex);
1832 mutex_unlock(&trace_types_lock);
1833
1834 return 0;
1835 }
1836
1837 static struct notifier_block trace_module_nb = {
1838 .notifier_call = trace_module_notify,
1839 .priority = 0,
1840 };
1841 #endif /* CONFIG_MODULES */
1842
1843 /* Create a new event directory structure for a trace directory. */
1844 static void
1845 __trace_add_event_dirs(struct trace_array *tr)
1846 {
1847 struct ftrace_event_call *call;
1848 int ret;
1849
1850 list_for_each_entry(call, &ftrace_events, list) {
1851 ret = __trace_add_new_event(call, tr);
1852 if (ret < 0)
1853 pr_warning("Could not create directory for event %s\n",
1854 call->name);
1855 }
1856 }
1857
1858 struct ftrace_event_file *
1859 find_event_file(struct trace_array *tr, const char *system, const char *event)
1860 {
1861 struct ftrace_event_file *file;
1862 struct ftrace_event_call *call;
1863
1864 list_for_each_entry(file, &tr->events, list) {
1865
1866 call = file->event_call;
1867
1868 if (!call->name || !call->class || !call->class->reg)
1869 continue;
1870
1871 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1872 continue;
1873
1874 if (strcmp(event, call->name) == 0 &&
1875 strcmp(system, call->class->system) == 0)
1876 return file;
1877 }
1878 return NULL;
1879 }
1880
1881 #ifdef CONFIG_DYNAMIC_FTRACE
1882
1883 /* Avoid typos */
1884 #define ENABLE_EVENT_STR "enable_event"
1885 #define DISABLE_EVENT_STR "disable_event"
1886
1887 struct event_probe_data {
1888 struct ftrace_event_file *file;
1889 unsigned long count;
1890 int ref;
1891 bool enable;
1892 };
1893
1894 static void
1895 event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1896 {
1897 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1898 struct event_probe_data *data = *pdata;
1899
1900 if (!data)
1901 return;
1902
1903 if (data->enable)
1904 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1905 else
1906 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1907 }
1908
1909 static void
1910 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1911 {
1912 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1913 struct event_probe_data *data = *pdata;
1914
1915 if (!data)
1916 return;
1917
1918 if (!data->count)
1919 return;
1920
1921 /* Skip if the event is in a state we want to switch to */
1922 if (data->enable == !(data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
1923 return;
1924
1925 if (data->count != -1)
1926 (data->count)--;
1927
1928 event_enable_probe(ip, parent_ip, _data);
1929 }
1930
1931 static int
1932 event_enable_print(struct seq_file *m, unsigned long ip,
1933 struct ftrace_probe_ops *ops, void *_data)
1934 {
1935 struct event_probe_data *data = _data;
1936
1937 seq_printf(m, "%ps:", (void *)ip);
1938
1939 seq_printf(m, "%s:%s:%s",
1940 data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
1941 data->file->event_call->class->system,
1942 data->file->event_call->name);
1943
1944 if (data->count == -1)
1945 seq_printf(m, ":unlimited\n");
1946 else
1947 seq_printf(m, ":count=%ld\n", data->count);
1948
1949 return 0;
1950 }
1951
1952 static int
1953 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
1954 void **_data)
1955 {
1956 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1957 struct event_probe_data *data = *pdata;
1958
1959 data->ref++;
1960 return 0;
1961 }
1962
1963 static void
1964 event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
1965 void **_data)
1966 {
1967 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1968 struct event_probe_data *data = *pdata;
1969
1970 if (WARN_ON_ONCE(data->ref <= 0))
1971 return;
1972
1973 data->ref--;
1974 if (!data->ref) {
1975 /* Remove the SOFT_MODE flag */
1976 __ftrace_event_enable_disable(data->file, 0, 1);
1977 module_put(data->file->event_call->mod);
1978 kfree(data);
1979 }
1980 *pdata = NULL;
1981 }
1982
1983 static struct ftrace_probe_ops event_enable_probe_ops = {
1984 .func = event_enable_probe,
1985 .print = event_enable_print,
1986 .init = event_enable_init,
1987 .free = event_enable_free,
1988 };
1989
1990 static struct ftrace_probe_ops event_enable_count_probe_ops = {
1991 .func = event_enable_count_probe,
1992 .print = event_enable_print,
1993 .init = event_enable_init,
1994 .free = event_enable_free,
1995 };
1996
1997 static struct ftrace_probe_ops event_disable_probe_ops = {
1998 .func = event_enable_probe,
1999 .print = event_enable_print,
2000 .init = event_enable_init,
2001 .free = event_enable_free,
2002 };
2003
2004 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2005 .func = event_enable_count_probe,
2006 .print = event_enable_print,
2007 .init = event_enable_init,
2008 .free = event_enable_free,
2009 };
2010
2011 static int
2012 event_enable_func(struct ftrace_hash *hash,
2013 char *glob, char *cmd, char *param, int enabled)
2014 {
2015 struct trace_array *tr = top_trace_array();
2016 struct ftrace_event_file *file;
2017 struct ftrace_probe_ops *ops;
2018 struct event_probe_data *data;
2019 const char *system;
2020 const char *event;
2021 char *number;
2022 bool enable;
2023 int ret;
2024
2025 /* hash funcs only work with set_ftrace_filter */
2026 if (!enabled || !param)
2027 return -EINVAL;
2028
2029 system = strsep(&param, ":");
2030 if (!param)
2031 return -EINVAL;
2032
2033 event = strsep(&param, ":");
2034
2035 mutex_lock(&event_mutex);
2036
2037 ret = -EINVAL;
2038 file = find_event_file(tr, system, event);
2039 if (!file)
2040 goto out;
2041
2042 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2043
2044 if (enable)
2045 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2046 else
2047 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2048
2049 if (glob[0] == '!') {
2050 unregister_ftrace_function_probe_func(glob+1, ops);
2051 ret = 0;
2052 goto out;
2053 }
2054
2055 ret = -ENOMEM;
2056 data = kzalloc(sizeof(*data), GFP_KERNEL);
2057 if (!data)
2058 goto out;
2059
2060 data->enable = enable;
2061 data->count = -1;
2062 data->file = file;
2063
2064 if (!param)
2065 goto out_reg;
2066
2067 number = strsep(&param, ":");
2068
2069 ret = -EINVAL;
2070 if (!strlen(number))
2071 goto out_free;
2072
2073 /*
2074 * We use the callback data field (which is a pointer)
2075 * as our counter.
2076 */
2077 ret = kstrtoul(number, 0, &data->count);
2078 if (ret)
2079 goto out_free;
2080
2081 out_reg:
2082 /* Don't let event modules unload while probe registered */
2083 ret = try_module_get(file->event_call->mod);
2084 if (!ret) {
2085 ret = -EBUSY;
2086 goto out_free;
2087 }
2088
2089 ret = __ftrace_event_enable_disable(file, 1, 1);
2090 if (ret < 0)
2091 goto out_put;
2092 ret = register_ftrace_function_probe(glob, ops, data);
2093 /*
2094 * The above returns on success the # of functions enabled,
2095 * but if it didn't find any functions it returns zero.
2096 * Consider no functions a failure too.
2097 */
2098 if (!ret) {
2099 ret = -ENOENT;
2100 goto out_disable;
2101 } else if (ret < 0)
2102 goto out_disable;
2103 /* Just return zero, not the number of enabled functions */
2104 ret = 0;
2105 out:
2106 mutex_unlock(&event_mutex);
2107 return ret;
2108
2109 out_disable:
2110 __ftrace_event_enable_disable(file, 0, 1);
2111 out_put:
2112 module_put(file->event_call->mod);
2113 out_free:
2114 kfree(data);
2115 goto out;
2116 }
2117
2118 static struct ftrace_func_command event_enable_cmd = {
2119 .name = ENABLE_EVENT_STR,
2120 .func = event_enable_func,
2121 };
2122
2123 static struct ftrace_func_command event_disable_cmd = {
2124 .name = DISABLE_EVENT_STR,
2125 .func = event_enable_func,
2126 };
2127
2128 static __init int register_event_cmds(void)
2129 {
2130 int ret;
2131
2132 ret = register_ftrace_command(&event_enable_cmd);
2133 if (WARN_ON(ret < 0))
2134 return ret;
2135 ret = register_ftrace_command(&event_disable_cmd);
2136 if (WARN_ON(ret < 0))
2137 unregister_ftrace_command(&event_enable_cmd);
2138 return ret;
2139 }
2140 #else
2141 static inline int register_event_cmds(void) { return 0; }
2142 #endif /* CONFIG_DYNAMIC_FTRACE */
2143
2144 /*
2145 * The top level array has already had its ftrace_event_file
2146 * descriptors created in order to allow for early events to
2147 * be recorded. This function is called after the debugfs has been
2148 * initialized, and we now have to create the files associated
2149 * to the events.
2150 */
2151 static __init void
2152 __trace_early_add_event_dirs(struct trace_array *tr)
2153 {
2154 struct ftrace_event_file *file;
2155 int ret;
2156
2157
2158 list_for_each_entry(file, &tr->events, list) {
2159 ret = event_create_dir(tr->event_dir, file);
2160 if (ret < 0)
2161 pr_warning("Could not create directory for event %s\n",
2162 file->event_call->name);
2163 }
2164 }
2165
2166 /*
2167 * For early boot up, the top trace array requires to have
2168 * a list of events that can be enabled. This must be done before
2169 * the filesystem is set up in order to allow events to be traced
2170 * early.
2171 */
2172 static __init void
2173 __trace_early_add_events(struct trace_array *tr)
2174 {
2175 struct ftrace_event_call *call;
2176 int ret;
2177
2178 list_for_each_entry(call, &ftrace_events, list) {
2179 /* Early boot up should not have any modules loaded */
2180 if (WARN_ON_ONCE(call->mod))
2181 continue;
2182
2183 ret = __trace_early_add_new_event(call, tr);
2184 if (ret < 0)
2185 pr_warning("Could not create early event %s\n",
2186 call->name);
2187 }
2188 }
2189
2190 /* Remove the event directory structure for a trace directory. */
2191 static void
2192 __trace_remove_event_dirs(struct trace_array *tr)
2193 {
2194 struct ftrace_event_file *file, *next;
2195
2196 list_for_each_entry_safe(file, next, &tr->events, list)
2197 remove_event_file_dir(file);
2198 }
2199
2200 static void __add_event_to_tracers(struct ftrace_event_call *call)
2201 {
2202 struct trace_array *tr;
2203
2204 list_for_each_entry(tr, &ftrace_trace_arrays, list)
2205 __trace_add_new_event(call, tr);
2206 }
2207
2208 extern struct ftrace_event_call *__start_ftrace_events[];
2209 extern struct ftrace_event_call *__stop_ftrace_events[];
2210
2211 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2212
2213 static __init int setup_trace_event(char *str)
2214 {
2215 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2216 ring_buffer_expanded = true;
2217 tracing_selftest_disabled = true;
2218
2219 return 1;
2220 }
2221 __setup("trace_event=", setup_trace_event);
2222
2223 /* Expects to have event_mutex held when called */
2224 static int
2225 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2226 {
2227 struct dentry *d_events;
2228 struct dentry *entry;
2229
2230 entry = debugfs_create_file("set_event", 0644, parent,
2231 tr, &ftrace_set_event_fops);
2232 if (!entry) {
2233 pr_warning("Could not create debugfs 'set_event' entry\n");
2234 return -ENOMEM;
2235 }
2236
2237 d_events = debugfs_create_dir("events", parent);
2238 if (!d_events) {
2239 pr_warning("Could not create debugfs 'events' directory\n");
2240 return -ENOMEM;
2241 }
2242
2243 /* ring buffer internal formats */
2244 trace_create_file("header_page", 0444, d_events,
2245 ring_buffer_print_page_header,
2246 &ftrace_show_header_fops);
2247
2248 trace_create_file("header_event", 0444, d_events,
2249 ring_buffer_print_entry_header,
2250 &ftrace_show_header_fops);
2251
2252 trace_create_file("enable", 0644, d_events,
2253 tr, &ftrace_tr_enable_fops);
2254
2255 tr->event_dir = d_events;
2256
2257 return 0;
2258 }
2259
2260 /**
2261 * event_trace_add_tracer - add a instance of a trace_array to events
2262 * @parent: The parent dentry to place the files/directories for events in
2263 * @tr: The trace array associated with these events
2264 *
2265 * When a new instance is created, it needs to set up its events
2266 * directory, as well as other files associated with events. It also
2267 * creates the event hierachry in the @parent/events directory.
2268 *
2269 * Returns 0 on success.
2270 */
2271 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2272 {
2273 int ret;
2274
2275 mutex_lock(&event_mutex);
2276
2277 ret = create_event_toplevel_files(parent, tr);
2278 if (ret)
2279 goto out_unlock;
2280
2281 down_write(&trace_event_sem);
2282 __trace_add_event_dirs(tr);
2283 up_write(&trace_event_sem);
2284
2285 out_unlock:
2286 mutex_unlock(&event_mutex);
2287
2288 return ret;
2289 }
2290
2291 /*
2292 * The top trace array already had its file descriptors created.
2293 * Now the files themselves need to be created.
2294 */
2295 static __init int
2296 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2297 {
2298 int ret;
2299
2300 mutex_lock(&event_mutex);
2301
2302 ret = create_event_toplevel_files(parent, tr);
2303 if (ret)
2304 goto out_unlock;
2305
2306 down_write(&trace_event_sem);
2307 __trace_early_add_event_dirs(tr);
2308 up_write(&trace_event_sem);
2309
2310 out_unlock:
2311 mutex_unlock(&event_mutex);
2312
2313 return ret;
2314 }
2315
2316 int event_trace_del_tracer(struct trace_array *tr)
2317 {
2318 mutex_lock(&event_mutex);
2319
2320 /* Disable any event triggers and associated soft-disabled events */
2321 clear_event_triggers(tr);
2322
2323 /* Disable any running events */
2324 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
2325
2326 /* Access to events are within rcu_read_lock_sched() */
2327 synchronize_sched();
2328
2329 down_write(&trace_event_sem);
2330 __trace_remove_event_dirs(tr);
2331 debugfs_remove_recursive(tr->event_dir);
2332 up_write(&trace_event_sem);
2333
2334 tr->event_dir = NULL;
2335
2336 mutex_unlock(&event_mutex);
2337
2338 return 0;
2339 }
2340
2341 static __init int event_trace_memsetup(void)
2342 {
2343 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
2344 file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC);
2345 return 0;
2346 }
2347
2348 static __init int event_trace_enable(void)
2349 {
2350 struct trace_array *tr = top_trace_array();
2351 struct ftrace_event_call **iter, *call;
2352 char *buf = bootup_event_buf;
2353 char *token;
2354 int ret;
2355
2356 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
2357
2358 call = *iter;
2359 ret = event_init(call);
2360 if (!ret)
2361 list_add(&call->list, &ftrace_events);
2362 }
2363
2364 /*
2365 * We need the top trace array to have a working set of trace
2366 * points at early init, before the debug files and directories
2367 * are created. Create the file entries now, and attach them
2368 * to the actual file dentries later.
2369 */
2370 __trace_early_add_events(tr);
2371
2372 while (true) {
2373 token = strsep(&buf, ",");
2374
2375 if (!token)
2376 break;
2377 if (!*token)
2378 continue;
2379
2380 ret = ftrace_set_clr_event(tr, token, 1);
2381 if (ret)
2382 pr_warn("Failed to enable trace event: %s\n", token);
2383 }
2384
2385 trace_printk_start_comm();
2386
2387 register_event_cmds();
2388
2389 register_trigger_cmds();
2390
2391 return 0;
2392 }
2393
2394 static __init int event_trace_init(void)
2395 {
2396 struct trace_array *tr;
2397 struct dentry *d_tracer;
2398 struct dentry *entry;
2399 int ret;
2400
2401 tr = top_trace_array();
2402
2403 d_tracer = tracing_init_dentry();
2404 if (!d_tracer)
2405 return 0;
2406
2407 entry = debugfs_create_file("available_events", 0444, d_tracer,
2408 tr, &ftrace_avail_fops);
2409 if (!entry)
2410 pr_warning("Could not create debugfs "
2411 "'available_events' entry\n");
2412
2413 if (trace_define_common_fields())
2414 pr_warning("tracing: Failed to allocate common fields");
2415
2416 ret = early_event_add_tracer(d_tracer, tr);
2417 if (ret)
2418 return ret;
2419
2420 #ifdef CONFIG_MODULES
2421 ret = register_module_notifier(&trace_module_nb);
2422 if (ret)
2423 pr_warning("Failed to register trace events module notifier\n");
2424 #endif
2425 return 0;
2426 }
2427 early_initcall(event_trace_memsetup);
2428 core_initcall(event_trace_enable);
2429 fs_initcall(event_trace_init);
2430
2431 #ifdef CONFIG_FTRACE_STARTUP_TEST
2432
2433 static DEFINE_SPINLOCK(test_spinlock);
2434 static DEFINE_SPINLOCK(test_spinlock_irq);
2435 static DEFINE_MUTEX(test_mutex);
2436
2437 static __init void test_work(struct work_struct *dummy)
2438 {
2439 spin_lock(&test_spinlock);
2440 spin_lock_irq(&test_spinlock_irq);
2441 udelay(1);
2442 spin_unlock_irq(&test_spinlock_irq);
2443 spin_unlock(&test_spinlock);
2444
2445 mutex_lock(&test_mutex);
2446 msleep(1);
2447 mutex_unlock(&test_mutex);
2448 }
2449
2450 static __init int event_test_thread(void *unused)
2451 {
2452 void *test_malloc;
2453
2454 test_malloc = kmalloc(1234, GFP_KERNEL);
2455 if (!test_malloc)
2456 pr_info("failed to kmalloc\n");
2457
2458 schedule_on_each_cpu(test_work);
2459
2460 kfree(test_malloc);
2461
2462 set_current_state(TASK_INTERRUPTIBLE);
2463 while (!kthread_should_stop())
2464 schedule();
2465
2466 return 0;
2467 }
2468
2469 /*
2470 * Do various things that may trigger events.
2471 */
2472 static __init void event_test_stuff(void)
2473 {
2474 struct task_struct *test_thread;
2475
2476 test_thread = kthread_run(event_test_thread, NULL, "test-events");
2477 msleep(1);
2478 kthread_stop(test_thread);
2479 }
2480
2481 /*
2482 * For every trace event defined, we will test each trace point separately,
2483 * and then by groups, and finally all trace points.
2484 */
2485 static __init void event_trace_self_tests(void)
2486 {
2487 struct ftrace_subsystem_dir *dir;
2488 struct ftrace_event_file *file;
2489 struct ftrace_event_call *call;
2490 struct event_subsystem *system;
2491 struct trace_array *tr;
2492 int ret;
2493
2494 tr = top_trace_array();
2495
2496 pr_info("Running tests on trace events:\n");
2497
2498 list_for_each_entry(file, &tr->events, list) {
2499
2500 call = file->event_call;
2501
2502 /* Only test those that have a probe */
2503 if (!call->class || !call->class->probe)
2504 continue;
2505
2506 /*
2507 * Testing syscall events here is pretty useless, but
2508 * we still do it if configured. But this is time consuming.
2509 * What we really need is a user thread to perform the
2510 * syscalls as we test.
2511 */
2512 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
2513 if (call->class->system &&
2514 strcmp(call->class->system, "syscalls") == 0)
2515 continue;
2516 #endif
2517
2518 pr_info("Testing event %s: ", call->name);
2519
2520 /*
2521 * If an event is already enabled, someone is using
2522 * it and the self test should not be on.
2523 */
2524 if (file->flags & FTRACE_EVENT_FL_ENABLED) {
2525 pr_warning("Enabled event during self test!\n");
2526 WARN_ON_ONCE(1);
2527 continue;
2528 }
2529
2530 ftrace_event_enable_disable(file, 1);
2531 event_test_stuff();
2532 ftrace_event_enable_disable(file, 0);
2533
2534 pr_cont("OK\n");
2535 }
2536
2537 /* Now test at the sub system level */
2538
2539 pr_info("Running tests on trace event systems:\n");
2540
2541 list_for_each_entry(dir, &tr->systems, list) {
2542
2543 system = dir->subsystem;
2544
2545 /* the ftrace system is special, skip it */
2546 if (strcmp(system->name, "ftrace") == 0)
2547 continue;
2548
2549 pr_info("Testing event system %s: ", system->name);
2550
2551 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
2552 if (WARN_ON_ONCE(ret)) {
2553 pr_warning("error enabling system %s\n",
2554 system->name);
2555 continue;
2556 }
2557
2558 event_test_stuff();
2559
2560 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
2561 if (WARN_ON_ONCE(ret)) {
2562 pr_warning("error disabling system %s\n",
2563 system->name);
2564 continue;
2565 }
2566
2567 pr_cont("OK\n");
2568 }
2569
2570 /* Test with all events enabled */
2571
2572 pr_info("Running tests on all trace events:\n");
2573 pr_info("Testing all events: ");
2574
2575 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
2576 if (WARN_ON_ONCE(ret)) {
2577 pr_warning("error enabling all events\n");
2578 return;
2579 }
2580
2581 event_test_stuff();
2582
2583 /* reset sysname */
2584 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
2585 if (WARN_ON_ONCE(ret)) {
2586 pr_warning("error disabling all events\n");
2587 return;
2588 }
2589
2590 pr_cont("OK\n");
2591 }
2592
2593 #ifdef CONFIG_FUNCTION_TRACER
2594
2595 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
2596
2597 static void
2598 function_test_events_call(unsigned long ip, unsigned long parent_ip,
2599 struct ftrace_ops *op, struct pt_regs *pt_regs)
2600 {
2601 struct ring_buffer_event *event;
2602 struct ring_buffer *buffer;
2603 struct ftrace_entry *entry;
2604 unsigned long flags;
2605 long disabled;
2606 int cpu;
2607 int pc;
2608
2609 pc = preempt_count();
2610 preempt_disable_notrace();
2611 cpu = raw_smp_processor_id();
2612 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
2613
2614 if (disabled != 1)
2615 goto out;
2616
2617 local_save_flags(flags);
2618
2619 event = trace_current_buffer_lock_reserve(&buffer,
2620 TRACE_FN, sizeof(*entry),
2621 flags, pc);
2622 if (!event)
2623 goto out;
2624 entry = ring_buffer_event_data(event);
2625 entry->ip = ip;
2626 entry->parent_ip = parent_ip;
2627
2628 trace_buffer_unlock_commit(buffer, event, flags, pc);
2629
2630 out:
2631 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
2632 preempt_enable_notrace();
2633 }
2634
2635 static struct ftrace_ops trace_ops __initdata =
2636 {
2637 .func = function_test_events_call,
2638 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
2639 };
2640
2641 static __init void event_trace_self_test_with_function(void)
2642 {
2643 int ret;
2644 ret = register_ftrace_function(&trace_ops);
2645 if (WARN_ON(ret < 0)) {
2646 pr_info("Failed to enable function tracer for event tests\n");
2647 return;
2648 }
2649 pr_info("Running tests again, along with the function tracer\n");
2650 event_trace_self_tests();
2651 unregister_ftrace_function(&trace_ops);
2652 }
2653 #else
2654 static __init void event_trace_self_test_with_function(void)
2655 {
2656 }
2657 #endif
2658
2659 static __init int event_trace_self_tests_init(void)
2660 {
2661 if (!tracing_selftest_disabled) {
2662 event_trace_self_tests();
2663 event_trace_self_test_with_function();
2664 }
2665
2666 return 0;
2667 }
2668
2669 late_initcall(event_trace_self_tests_init);
2670
2671 #endif
Linux kernel - Deliverables
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