projects / deliverable / linux.git / blob
? search:


7a75cb22eab76150bbfae09a3189ef659d4da65f
[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 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 /*
413 * Open and update trace_array ref count.
414 * Must have the current trace_array passed to it.
415 */
416 static int tracing_open_generic_file(struct inode *inode, struct file *filp)
417 {
418 struct ftrace_event_file *file = inode->i_private;
419 struct trace_array *tr = file->tr;
420 int ret;
421
422 if (trace_array_get(tr) < 0)
423 return -ENODEV;
424
425 ret = tracing_open_generic(inode, filp);
426 if (ret < 0)
427 trace_array_put(tr);
428 return ret;
429 }
430
431 static int tracing_release_generic_file(struct inode *inode, struct file *filp)
432 {
433 struct ftrace_event_file *file = inode->i_private;
434 struct trace_array *tr = file->tr;
435
436 trace_array_put(tr);
437
438 return 0;
439 }
440
441 /*
442 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
443 */
444 static int
445 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
446 const char *sub, const char *event, int set)
447 {
448 struct ftrace_event_file *file;
449 struct ftrace_event_call *call;
450 int ret = -EINVAL;
451
452 list_for_each_entry(file, &tr->events, list) {
453
454 call = file->event_call;
455
456 if (!call->name || !call->class || !call->class->reg)
457 continue;
458
459 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
460 continue;
461
462 if (match &&
463 strcmp(match, call->name) != 0 &&
464 strcmp(match, call->class->system) != 0)
465 continue;
466
467 if (sub && strcmp(sub, call->class->system) != 0)
468 continue;
469
470 if (event && strcmp(event, call->name) != 0)
471 continue;
472
473 ftrace_event_enable_disable(file, set);
474
475 ret = 0;
476 }
477
478 return ret;
479 }
480
481 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
482 const char *sub, const char *event, int set)
483 {
484 int ret;
485
486 mutex_lock(&event_mutex);
487 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
488 mutex_unlock(&event_mutex);
489
490 return ret;
491 }
492
493 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
494 {
495 char *event = NULL, *sub = NULL, *match;
496
497 /*
498 * The buf format can be <subsystem>:<event-name>
499 * *:<event-name> means any event by that name.
500 * :<event-name> is the same.
501 *
502 * <subsystem>:* means all events in that subsystem
503 * <subsystem>: means the same.
504 *
505 * <name> (no ':') means all events in a subsystem with
506 * the name <name> or any event that matches <name>
507 */
508
509 match = strsep(&buf, ":");
510 if (buf) {
511 sub = match;
512 event = buf;
513 match = NULL;
514
515 if (!strlen(sub) || strcmp(sub, "*") == 0)
516 sub = NULL;
517 if (!strlen(event) || strcmp(event, "*") == 0)
518 event = NULL;
519 }
520
521 return __ftrace_set_clr_event(tr, match, sub, event, set);
522 }
523
524 /**
525 * trace_set_clr_event - enable or disable an event
526 * @system: system name to match (NULL for any system)
527 * @event: event name to match (NULL for all events, within system)
528 * @set: 1 to enable, 0 to disable
529 *
530 * This is a way for other parts of the kernel to enable or disable
531 * event recording.
532 *
533 * Returns 0 on success, -EINVAL if the parameters do not match any
534 * registered events.
535 */
536 int trace_set_clr_event(const char *system, const char *event, int set)
537 {
538 struct trace_array *tr = top_trace_array();
539
540 return __ftrace_set_clr_event(tr, NULL, system, event, set);
541 }
542 EXPORT_SYMBOL_GPL(trace_set_clr_event);
543
544 /* 128 should be much more than enough */
545 #define EVENT_BUF_SIZE 127
546
547 static ssize_t
548 ftrace_event_write(struct file *file, const char __user *ubuf,
549 size_t cnt, loff_t *ppos)
550 {
551 struct trace_parser parser;
552 struct seq_file *m = file->private_data;
553 struct trace_array *tr = m->private;
554 ssize_t read, ret;
555
556 if (!cnt)
557 return 0;
558
559 ret = tracing_update_buffers();
560 if (ret < 0)
561 return ret;
562
563 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
564 return -ENOMEM;
565
566 read = trace_get_user(&parser, ubuf, cnt, ppos);
567
568 if (read >= 0 && trace_parser_loaded((&parser))) {
569 int set = 1;
570
571 if (*parser.buffer == '!')
572 set = 0;
573
574 parser.buffer[parser.idx] = 0;
575
576 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
577 if (ret)
578 goto out_put;
579 }
580
581 ret = read;
582
583 out_put:
584 trace_parser_put(&parser);
585
586 return ret;
587 }
588
589 static void *
590 t_next(struct seq_file *m, void *v, loff_t *pos)
591 {
592 struct ftrace_event_file *file = v;
593 struct ftrace_event_call *call;
594 struct trace_array *tr = m->private;
595
596 (*pos)++;
597
598 list_for_each_entry_continue(file, &tr->events, list) {
599 call = file->event_call;
600 /*
601 * The ftrace subsystem is for showing formats only.
602 * They can not be enabled or disabled via the event files.
603 */
604 if (call->class && call->class->reg)
605 return file;
606 }
607
608 return NULL;
609 }
610
611 static void *t_start(struct seq_file *m, loff_t *pos)
612 {
613 struct ftrace_event_file *file;
614 struct trace_array *tr = m->private;
615 loff_t l;
616
617 mutex_lock(&event_mutex);
618
619 file = list_entry(&tr->events, struct ftrace_event_file, list);
620 for (l = 0; l <= *pos; ) {
621 file = t_next(m, file, &l);
622 if (!file)
623 break;
624 }
625 return file;
626 }
627
628 static void *
629 s_next(struct seq_file *m, void *v, loff_t *pos)
630 {
631 struct ftrace_event_file *file = v;
632 struct trace_array *tr = m->private;
633
634 (*pos)++;
635
636 list_for_each_entry_continue(file, &tr->events, list) {
637 if (file->flags & FTRACE_EVENT_FL_ENABLED)
638 return file;
639 }
640
641 return NULL;
642 }
643
644 static void *s_start(struct seq_file *m, loff_t *pos)
645 {
646 struct ftrace_event_file *file;
647 struct trace_array *tr = m->private;
648 loff_t l;
649
650 mutex_lock(&event_mutex);
651
652 file = list_entry(&tr->events, struct ftrace_event_file, list);
653 for (l = 0; l <= *pos; ) {
654 file = s_next(m, file, &l);
655 if (!file)
656 break;
657 }
658 return file;
659 }
660
661 static int t_show(struct seq_file *m, void *v)
662 {
663 struct ftrace_event_file *file = v;
664 struct ftrace_event_call *call = file->event_call;
665
666 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
667 seq_printf(m, "%s:", call->class->system);
668 seq_printf(m, "%s\n", call->name);
669
670 return 0;
671 }
672
673 static void t_stop(struct seq_file *m, void *p)
674 {
675 mutex_unlock(&event_mutex);
676 }
677
678 static ssize_t
679 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
680 loff_t *ppos)
681 {
682 struct ftrace_event_file *file = filp->private_data;
683 char buf[4] = "0";
684
685 if (file->flags & FTRACE_EVENT_FL_ENABLED &&
686 !(file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
687 strcpy(buf, "1");
688
689 if (file->flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
690 file->flags & FTRACE_EVENT_FL_SOFT_MODE)
691 strcat(buf, "*");
692
693 strcat(buf, "\n");
694
695 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
696 }
697
698 static ssize_t
699 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
700 loff_t *ppos)
701 {
702 struct ftrace_event_file *file = filp->private_data;
703 unsigned long val;
704 int ret;
705
706 if (!file)
707 return -EINVAL;
708
709 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
710 if (ret)
711 return ret;
712
713 ret = tracing_update_buffers();
714 if (ret < 0)
715 return ret;
716
717 switch (val) {
718 case 0:
719 case 1:
720 mutex_lock(&event_mutex);
721 ret = ftrace_event_enable_disable(file, val);
722 mutex_unlock(&event_mutex);
723 break;
724
725 default:
726 return -EINVAL;
727 }
728
729 *ppos += cnt;
730
731 return ret ? ret : cnt;
732 }
733
734 static ssize_t
735 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
736 loff_t *ppos)
737 {
738 const char set_to_char[4] = { '?', '0', '1', 'X' };
739 struct ftrace_subsystem_dir *dir = filp->private_data;
740 struct event_subsystem *system = dir->subsystem;
741 struct ftrace_event_call *call;
742 struct ftrace_event_file *file;
743 struct trace_array *tr = dir->tr;
744 char buf[2];
745 int set = 0;
746 int ret;
747
748 mutex_lock(&event_mutex);
749 list_for_each_entry(file, &tr->events, list) {
750 call = file->event_call;
751 if (!call->name || !call->class || !call->class->reg)
752 continue;
753
754 if (system && strcmp(call->class->system, system->name) != 0)
755 continue;
756
757 /*
758 * We need to find out if all the events are set
759 * or if all events or cleared, or if we have
760 * a mixture.
761 */
762 set |= (1 << !!(file->flags & FTRACE_EVENT_FL_ENABLED));
763
764 /*
765 * If we have a mixture, no need to look further.
766 */
767 if (set == 3)
768 break;
769 }
770 mutex_unlock(&event_mutex);
771
772 buf[0] = set_to_char[set];
773 buf[1] = '\n';
774
775 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
776
777 return ret;
778 }
779
780 static ssize_t
781 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
782 loff_t *ppos)
783 {
784 struct ftrace_subsystem_dir *dir = filp->private_data;
785 struct event_subsystem *system = dir->subsystem;
786 const char *name = NULL;
787 unsigned long val;
788 ssize_t ret;
789
790 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
791 if (ret)
792 return ret;
793
794 ret = tracing_update_buffers();
795 if (ret < 0)
796 return ret;
797
798 if (val != 0 && val != 1)
799 return -EINVAL;
800
801 /*
802 * Opening of "enable" adds a ref count to system,
803 * so the name is safe to use.
804 */
805 if (system)
806 name = system->name;
807
808 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
809 if (ret)
810 goto out;
811
812 ret = cnt;
813
814 out:
815 *ppos += cnt;
816
817 return ret;
818 }
819
820 enum {
821 FORMAT_HEADER = 1,
822 FORMAT_FIELD_SEPERATOR = 2,
823 FORMAT_PRINTFMT = 3,
824 };
825
826 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
827 {
828 struct ftrace_event_call *call = m->private;
829 struct ftrace_event_field *field;
830 struct list_head *common_head = &ftrace_common_fields;
831 struct list_head *head = trace_get_fields(call);
832
833 (*pos)++;
834
835 switch ((unsigned long)v) {
836 case FORMAT_HEADER:
837 if (unlikely(list_empty(common_head)))
838 return NULL;
839
840 field = list_entry(common_head->prev,
841 struct ftrace_event_field, link);
842 return field;
843
844 case FORMAT_FIELD_SEPERATOR:
845 if (unlikely(list_empty(head)))
846 return NULL;
847
848 field = list_entry(head->prev, struct ftrace_event_field, link);
849 return field;
850
851 case FORMAT_PRINTFMT:
852 /* all done */
853 return NULL;
854 }
855
856 field = v;
857 if (field->link.prev == common_head)
858 return (void *)FORMAT_FIELD_SEPERATOR;
859 else if (field->link.prev == head)
860 return (void *)FORMAT_PRINTFMT;
861
862 field = list_entry(field->link.prev, struct ftrace_event_field, link);
863
864 return field;
865 }
866
867 static void *f_start(struct seq_file *m, loff_t *pos)
868 {
869 loff_t l = 0;
870 void *p;
871
872 /* Start by showing the header */
873 if (!*pos)
874 return (void *)FORMAT_HEADER;
875
876 p = (void *)FORMAT_HEADER;
877 do {
878 p = f_next(m, p, &l);
879 } while (p && l < *pos);
880
881 return p;
882 }
883
884 static int f_show(struct seq_file *m, void *v)
885 {
886 struct ftrace_event_call *call = m->private;
887 struct ftrace_event_field *field;
888 const char *array_descriptor;
889
890 switch ((unsigned long)v) {
891 case FORMAT_HEADER:
892 seq_printf(m, "name: %s\n", call->name);
893 seq_printf(m, "ID: %d\n", call->event.type);
894 seq_printf(m, "format:\n");
895 return 0;
896
897 case FORMAT_FIELD_SEPERATOR:
898 seq_putc(m, '\n');
899 return 0;
900
901 case FORMAT_PRINTFMT:
902 seq_printf(m, "\nprint fmt: %s\n",
903 call->print_fmt);
904 return 0;
905 }
906
907 field = v;
908
909 /*
910 * Smartly shows the array type(except dynamic array).
911 * Normal:
912 * field:TYPE VAR
913 * If TYPE := TYPE[LEN], it is shown:
914 * field:TYPE VAR[LEN]
915 */
916 array_descriptor = strchr(field->type, '[');
917
918 if (!strncmp(field->type, "__data_loc", 10))
919 array_descriptor = NULL;
920
921 if (!array_descriptor)
922 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
923 field->type, field->name, field->offset,
924 field->size, !!field->is_signed);
925 else
926 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
927 (int)(array_descriptor - field->type),
928 field->type, field->name,
929 array_descriptor, field->offset,
930 field->size, !!field->is_signed);
931
932 return 0;
933 }
934
935 static void f_stop(struct seq_file *m, void *p)
936 {
937 }
938
939 static const struct seq_operations trace_format_seq_ops = {
940 .start = f_start,
941 .next = f_next,
942 .stop = f_stop,
943 .show = f_show,
944 };
945
946 static int trace_format_open(struct inode *inode, struct file *file)
947 {
948 struct ftrace_event_call *call = inode->i_private;
949 struct seq_file *m;
950 int ret;
951
952 ret = seq_open(file, &trace_format_seq_ops);
953 if (ret < 0)
954 return ret;
955
956 m = file->private_data;
957 m->private = call;
958
959 return 0;
960 }
961
962 static ssize_t
963 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
964 {
965 struct ftrace_event_call *call = filp->private_data;
966 struct trace_seq *s;
967 int r;
968
969 if (*ppos)
970 return 0;
971
972 s = kmalloc(sizeof(*s), GFP_KERNEL);
973 if (!s)
974 return -ENOMEM;
975
976 trace_seq_init(s);
977 trace_seq_printf(s, "%d\n", call->event.type);
978
979 r = simple_read_from_buffer(ubuf, cnt, ppos,
980 s->buffer, s->len);
981 kfree(s);
982 return r;
983 }
984
985 static ssize_t
986 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
987 loff_t *ppos)
988 {
989 struct ftrace_event_call *call = filp->private_data;
990 struct trace_seq *s;
991 int r;
992
993 if (*ppos)
994 return 0;
995
996 s = kmalloc(sizeof(*s), GFP_KERNEL);
997 if (!s)
998 return -ENOMEM;
999
1000 trace_seq_init(s);
1001
1002 print_event_filter(call, s);
1003 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1004
1005 kfree(s);
1006
1007 return r;
1008 }
1009
1010 static ssize_t
1011 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1012 loff_t *ppos)
1013 {
1014 struct ftrace_event_call *call = filp->private_data;
1015 char *buf;
1016 int err;
1017
1018 if (cnt >= PAGE_SIZE)
1019 return -EINVAL;
1020
1021 buf = (char *)__get_free_page(GFP_TEMPORARY);
1022 if (!buf)
1023 return -ENOMEM;
1024
1025 if (copy_from_user(buf, ubuf, cnt)) {
1026 free_page((unsigned long) buf);
1027 return -EFAULT;
1028 }
1029 buf[cnt] = '\0';
1030
1031 err = apply_event_filter(call, buf);
1032 free_page((unsigned long) buf);
1033 if (err < 0)
1034 return err;
1035
1036 *ppos += cnt;
1037
1038 return cnt;
1039 }
1040
1041 static LIST_HEAD(event_subsystems);
1042
1043 static int subsystem_open(struct inode *inode, struct file *filp)
1044 {
1045 struct event_subsystem *system = NULL;
1046 struct ftrace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1047 struct trace_array *tr;
1048 int ret;
1049
1050 /* Make sure the system still exists */
1051 mutex_lock(&trace_types_lock);
1052 mutex_lock(&event_mutex);
1053 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1054 list_for_each_entry(dir, &tr->systems, list) {
1055 if (dir == inode->i_private) {
1056 /* Don't open systems with no events */
1057 if (dir->nr_events) {
1058 __get_system_dir(dir);
1059 system = dir->subsystem;
1060 }
1061 goto exit_loop;
1062 }
1063 }
1064 }
1065 exit_loop:
1066 mutex_unlock(&event_mutex);
1067 mutex_unlock(&trace_types_lock);
1068
1069 if (!system)
1070 return -ENODEV;
1071
1072 /* Some versions of gcc think dir can be uninitialized here */
1073 WARN_ON(!dir);
1074
1075 /* Still need to increment the ref count of the system */
1076 if (trace_array_get(tr) < 0) {
1077 put_system(dir);
1078 return -ENODEV;
1079 }
1080
1081 ret = tracing_open_generic(inode, filp);
1082 if (ret < 0) {
1083 trace_array_put(tr);
1084 put_system(dir);
1085 }
1086
1087 return ret;
1088 }
1089
1090 static int system_tr_open(struct inode *inode, struct file *filp)
1091 {
1092 struct ftrace_subsystem_dir *dir;
1093 struct trace_array *tr = inode->i_private;
1094 int ret;
1095
1096 if (trace_array_get(tr) < 0)
1097 return -ENODEV;
1098
1099 /* Make a temporary dir that has no system but points to tr */
1100 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1101 if (!dir) {
1102 trace_array_put(tr);
1103 return -ENOMEM;
1104 }
1105
1106 dir->tr = tr;
1107
1108 ret = tracing_open_generic(inode, filp);
1109 if (ret < 0) {
1110 trace_array_put(tr);
1111 kfree(dir);
1112 }
1113
1114 filp->private_data = dir;
1115
1116 return ret;
1117 }
1118
1119 static int subsystem_release(struct inode *inode, struct file *file)
1120 {
1121 struct ftrace_subsystem_dir *dir = file->private_data;
1122
1123 trace_array_put(dir->tr);
1124
1125 /*
1126 * If dir->subsystem is NULL, then this is a temporary
1127 * descriptor that was made for a trace_array to enable
1128 * all subsystems.
1129 */
1130 if (dir->subsystem)
1131 put_system(dir);
1132 else
1133 kfree(dir);
1134
1135 return 0;
1136 }
1137
1138 static ssize_t
1139 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1140 loff_t *ppos)
1141 {
1142 struct ftrace_subsystem_dir *dir = filp->private_data;
1143 struct event_subsystem *system = dir->subsystem;
1144 struct trace_seq *s;
1145 int r;
1146
1147 if (*ppos)
1148 return 0;
1149
1150 s = kmalloc(sizeof(*s), GFP_KERNEL);
1151 if (!s)
1152 return -ENOMEM;
1153
1154 trace_seq_init(s);
1155
1156 print_subsystem_event_filter(system, s);
1157 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1158
1159 kfree(s);
1160
1161 return r;
1162 }
1163
1164 static ssize_t
1165 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1166 loff_t *ppos)
1167 {
1168 struct ftrace_subsystem_dir *dir = filp->private_data;
1169 char *buf;
1170 int err;
1171
1172 if (cnt >= PAGE_SIZE)
1173 return -EINVAL;
1174
1175 buf = (char *)__get_free_page(GFP_TEMPORARY);
1176 if (!buf)
1177 return -ENOMEM;
1178
1179 if (copy_from_user(buf, ubuf, cnt)) {
1180 free_page((unsigned long) buf);
1181 return -EFAULT;
1182 }
1183 buf[cnt] = '\0';
1184
1185 err = apply_subsystem_event_filter(dir, buf);
1186 free_page((unsigned long) buf);
1187 if (err < 0)
1188 return err;
1189
1190 *ppos += cnt;
1191
1192 return cnt;
1193 }
1194
1195 static ssize_t
1196 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1197 {
1198 int (*func)(struct trace_seq *s) = filp->private_data;
1199 struct trace_seq *s;
1200 int r;
1201
1202 if (*ppos)
1203 return 0;
1204
1205 s = kmalloc(sizeof(*s), GFP_KERNEL);
1206 if (!s)
1207 return -ENOMEM;
1208
1209 trace_seq_init(s);
1210
1211 func(s);
1212 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1213
1214 kfree(s);
1215
1216 return r;
1217 }
1218
1219 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1220 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1221 static int ftrace_event_release(struct inode *inode, struct file *file);
1222
1223 static const struct seq_operations show_event_seq_ops = {
1224 .start = t_start,
1225 .next = t_next,
1226 .show = t_show,
1227 .stop = t_stop,
1228 };
1229
1230 static const struct seq_operations show_set_event_seq_ops = {
1231 .start = s_start,
1232 .next = s_next,
1233 .show = t_show,
1234 .stop = t_stop,
1235 };
1236
1237 static const struct file_operations ftrace_avail_fops = {
1238 .open = ftrace_event_avail_open,
1239 .read = seq_read,
1240 .llseek = seq_lseek,
1241 .release = seq_release,
1242 };
1243
1244 static const struct file_operations ftrace_set_event_fops = {
1245 .open = ftrace_event_set_open,
1246 .read = seq_read,
1247 .write = ftrace_event_write,
1248 .llseek = seq_lseek,
1249 .release = ftrace_event_release,
1250 };
1251
1252 static const struct file_operations ftrace_enable_fops = {
1253 .open = tracing_open_generic_file,
1254 .read = event_enable_read,
1255 .write = event_enable_write,
1256 .release = tracing_release_generic_file,
1257 .llseek = default_llseek,
1258 };
1259
1260 static const struct file_operations ftrace_event_format_fops = {
1261 .open = trace_format_open,
1262 .read = seq_read,
1263 .llseek = seq_lseek,
1264 .release = seq_release,
1265 };
1266
1267 static const struct file_operations ftrace_event_id_fops = {
1268 .open = tracing_open_generic,
1269 .read = event_id_read,
1270 .llseek = default_llseek,
1271 };
1272
1273 static const struct file_operations ftrace_event_filter_fops = {
1274 .open = tracing_open_generic,
1275 .read = event_filter_read,
1276 .write = event_filter_write,
1277 .llseek = default_llseek,
1278 };
1279
1280 static const struct file_operations ftrace_subsystem_filter_fops = {
1281 .open = subsystem_open,
1282 .read = subsystem_filter_read,
1283 .write = subsystem_filter_write,
1284 .llseek = default_llseek,
1285 .release = subsystem_release,
1286 };
1287
1288 static const struct file_operations ftrace_system_enable_fops = {
1289 .open = subsystem_open,
1290 .read = system_enable_read,
1291 .write = system_enable_write,
1292 .llseek = default_llseek,
1293 .release = subsystem_release,
1294 };
1295
1296 static const struct file_operations ftrace_tr_enable_fops = {
1297 .open = system_tr_open,
1298 .read = system_enable_read,
1299 .write = system_enable_write,
1300 .llseek = default_llseek,
1301 .release = subsystem_release,
1302 };
1303
1304 static const struct file_operations ftrace_show_header_fops = {
1305 .open = tracing_open_generic,
1306 .read = show_header,
1307 .llseek = default_llseek,
1308 };
1309
1310 static int
1311 ftrace_event_open(struct inode *inode, struct file *file,
1312 const struct seq_operations *seq_ops)
1313 {
1314 struct seq_file *m;
1315 int ret;
1316
1317 ret = seq_open(file, seq_ops);
1318 if (ret < 0)
1319 return ret;
1320 m = file->private_data;
1321 /* copy tr over to seq ops */
1322 m->private = inode->i_private;
1323
1324 return ret;
1325 }
1326
1327 static int ftrace_event_release(struct inode *inode, struct file *file)
1328 {
1329 struct trace_array *tr = inode->i_private;
1330
1331 trace_array_put(tr);
1332
1333 return seq_release(inode, file);
1334 }
1335
1336 static int
1337 ftrace_event_avail_open(struct inode *inode, struct file *file)
1338 {
1339 const struct seq_operations *seq_ops = &show_event_seq_ops;
1340
1341 return ftrace_event_open(inode, file, seq_ops);
1342 }
1343
1344 static int
1345 ftrace_event_set_open(struct inode *inode, struct file *file)
1346 {
1347 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1348 struct trace_array *tr = inode->i_private;
1349 int ret;
1350
1351 if (trace_array_get(tr) < 0)
1352 return -ENODEV;
1353
1354 if ((file->f_mode & FMODE_WRITE) &&
1355 (file->f_flags & O_TRUNC))
1356 ftrace_clear_events(tr);
1357
1358 ret = ftrace_event_open(inode, file, seq_ops);
1359 if (ret < 0)
1360 trace_array_put(tr);
1361 return ret;
1362 }
1363
1364 static struct event_subsystem *
1365 create_new_subsystem(const char *name)
1366 {
1367 struct event_subsystem *system;
1368
1369 /* need to create new entry */
1370 system = kmalloc(sizeof(*system), GFP_KERNEL);
1371 if (!system)
1372 return NULL;
1373
1374 system->ref_count = 1;
1375
1376 /* Only allocate if dynamic (kprobes and modules) */
1377 if (!core_kernel_data((unsigned long)name)) {
1378 system->ref_count |= SYSTEM_FL_FREE_NAME;
1379 system->name = kstrdup(name, GFP_KERNEL);
1380 if (!system->name)
1381 goto out_free;
1382 } else
1383 system->name = name;
1384
1385 system->filter = NULL;
1386
1387 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1388 if (!system->filter)
1389 goto out_free;
1390
1391 list_add(&system->list, &event_subsystems);
1392
1393 return system;
1394
1395 out_free:
1396 if (system->ref_count & SYSTEM_FL_FREE_NAME)
1397 kfree(system->name);
1398 kfree(system);
1399 return NULL;
1400 }
1401
1402 static struct dentry *
1403 event_subsystem_dir(struct trace_array *tr, const char *name,
1404 struct ftrace_event_file *file, struct dentry *parent)
1405 {
1406 struct ftrace_subsystem_dir *dir;
1407 struct event_subsystem *system;
1408 struct dentry *entry;
1409
1410 /* First see if we did not already create this dir */
1411 list_for_each_entry(dir, &tr->systems, list) {
1412 system = dir->subsystem;
1413 if (strcmp(system->name, name) == 0) {
1414 dir->nr_events++;
1415 file->system = dir;
1416 return dir->entry;
1417 }
1418 }
1419
1420 /* Now see if the system itself exists. */
1421 list_for_each_entry(system, &event_subsystems, list) {
1422 if (strcmp(system->name, name) == 0)
1423 break;
1424 }
1425 /* Reset system variable when not found */
1426 if (&system->list == &event_subsystems)
1427 system = NULL;
1428
1429 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1430 if (!dir)
1431 goto out_fail;
1432
1433 if (!system) {
1434 system = create_new_subsystem(name);
1435 if (!system)
1436 goto out_free;
1437 } else
1438 __get_system(system);
1439
1440 dir->entry = debugfs_create_dir(name, parent);
1441 if (!dir->entry) {
1442 pr_warning("Failed to create system directory %s\n", name);
1443 __put_system(system);
1444 goto out_free;
1445 }
1446
1447 dir->tr = tr;
1448 dir->ref_count = 1;
1449 dir->nr_events = 1;
1450 dir->subsystem = system;
1451 file->system = dir;
1452
1453 entry = debugfs_create_file("filter", 0644, dir->entry, dir,
1454 &ftrace_subsystem_filter_fops);
1455 if (!entry) {
1456 kfree(system->filter);
1457 system->filter = NULL;
1458 pr_warning("Could not create debugfs '%s/filter' entry\n", name);
1459 }
1460
1461 trace_create_file("enable", 0644, dir->entry, dir,
1462 &ftrace_system_enable_fops);
1463
1464 list_add(&dir->list, &tr->systems);
1465
1466 return dir->entry;
1467
1468 out_free:
1469 kfree(dir);
1470 out_fail:
1471 /* Only print this message if failed on memory allocation */
1472 if (!dir || !system)
1473 pr_warning("No memory to create event subsystem %s\n",
1474 name);
1475 return NULL;
1476 }
1477
1478 static int
1479 event_create_dir(struct dentry *parent,
1480 struct ftrace_event_file *file,
1481 const struct file_operations *id,
1482 const struct file_operations *enable,
1483 const struct file_operations *filter,
1484 const struct file_operations *format)
1485 {
1486 struct ftrace_event_call *call = file->event_call;
1487 struct trace_array *tr = file->tr;
1488 struct list_head *head;
1489 struct dentry *d_events;
1490 int ret;
1491
1492 /*
1493 * If the trace point header did not define TRACE_SYSTEM
1494 * then the system would be called "TRACE_SYSTEM".
1495 */
1496 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1497 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1498 if (!d_events)
1499 return -ENOMEM;
1500 } else
1501 d_events = parent;
1502
1503 file->dir = debugfs_create_dir(call->name, d_events);
1504 if (!file->dir) {
1505 pr_warning("Could not create debugfs '%s' directory\n",
1506 call->name);
1507 return -1;
1508 }
1509
1510 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1511 trace_create_file("enable", 0644, file->dir, file,
1512 enable);
1513
1514 #ifdef CONFIG_PERF_EVENTS
1515 if (call->event.type && call->class->reg)
1516 trace_create_file("id", 0444, file->dir, call,
1517 id);
1518 #endif
1519
1520 /*
1521 * Other events may have the same class. Only update
1522 * the fields if they are not already defined.
1523 */
1524 head = trace_get_fields(call);
1525 if (list_empty(head)) {
1526 ret = call->class->define_fields(call);
1527 if (ret < 0) {
1528 pr_warning("Could not initialize trace point"
1529 " events/%s\n", call->name);
1530 return -1;
1531 }
1532 }
1533 trace_create_file("filter", 0644, file->dir, call,
1534 filter);
1535
1536 trace_create_file("format", 0444, file->dir, call,
1537 format);
1538
1539 return 0;
1540 }
1541
1542 static void remove_subsystem(struct ftrace_subsystem_dir *dir)
1543 {
1544 if (!dir)
1545 return;
1546
1547 if (!--dir->nr_events) {
1548 debugfs_remove_recursive(dir->entry);
1549 list_del(&dir->list);
1550 __put_system_dir(dir);
1551 }
1552 }
1553
1554 static void remove_event_from_tracers(struct ftrace_event_call *call)
1555 {
1556 struct ftrace_event_file *file;
1557 struct trace_array *tr;
1558
1559 do_for_each_event_file_safe(tr, file) {
1560
1561 if (file->event_call != call)
1562 continue;
1563
1564 list_del(&file->list);
1565 debugfs_remove_recursive(file->dir);
1566 remove_subsystem(file->system);
1567 kmem_cache_free(file_cachep, file);
1568
1569 /*
1570 * The do_for_each_event_file_safe() is
1571 * a double loop. After finding the call for this
1572 * trace_array, we use break to jump to the next
1573 * trace_array.
1574 */
1575 break;
1576 } while_for_each_event_file();
1577 }
1578
1579 static void event_remove(struct ftrace_event_call *call)
1580 {
1581 struct trace_array *tr;
1582 struct ftrace_event_file *file;
1583
1584 do_for_each_event_file(tr, file) {
1585 if (file->event_call != call)
1586 continue;
1587 ftrace_event_enable_disable(file, 0);
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,
1656 struct trace_array *tr,
1657 const struct file_operations *id,
1658 const struct file_operations *enable,
1659 const struct file_operations *filter,
1660 const struct file_operations *format)
1661 {
1662 struct ftrace_event_file *file;
1663
1664 file = trace_create_new_event(call, tr);
1665 if (!file)
1666 return -ENOMEM;
1667
1668 return event_create_dir(tr->event_dir, file, id, enable, filter, format);
1669 }
1670
1671 /*
1672 * Just create a decriptor for early init. A descriptor is required
1673 * for enabling events at boot. We want to enable events before
1674 * the filesystem is initialized.
1675 */
1676 static __init int
1677 __trace_early_add_new_event(struct ftrace_event_call *call,
1678 struct trace_array *tr)
1679 {
1680 struct ftrace_event_file *file;
1681
1682 file = trace_create_new_event(call, tr);
1683 if (!file)
1684 return -ENOMEM;
1685
1686 return 0;
1687 }
1688
1689 struct ftrace_module_file_ops;
1690 static void __add_event_to_tracers(struct ftrace_event_call *call,
1691 struct ftrace_module_file_ops *file_ops);
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, NULL);
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_preds(call);
1718 }
1719
1720 /* Remove an event_call */
1721 void trace_remove_event_call(struct ftrace_event_call *call)
1722 {
1723 mutex_lock(&trace_types_lock);
1724 mutex_lock(&event_mutex);
1725 down_write(&trace_event_sem);
1726 __trace_remove_event_call(call);
1727 up_write(&trace_event_sem);
1728 mutex_unlock(&event_mutex);
1729 mutex_unlock(&trace_types_lock);
1730 }
1731
1732 #define for_each_event(event, start, end) \
1733 for (event = start; \
1734 (unsigned long)event < (unsigned long)end; \
1735 event++)
1736
1737 #ifdef CONFIG_MODULES
1738
1739 static LIST_HEAD(ftrace_module_file_list);
1740
1741 /*
1742 * Modules must own their file_operations to keep up with
1743 * reference counting.
1744 */
1745 struct ftrace_module_file_ops {
1746 struct list_head list;
1747 struct module *mod;
1748 struct file_operations id;
1749 struct file_operations enable;
1750 struct file_operations format;
1751 struct file_operations filter;
1752 };
1753
1754 static struct ftrace_module_file_ops *
1755 find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
1756 {
1757 /*
1758 * As event_calls are added in groups by module,
1759 * when we find one file_ops, we don't need to search for
1760 * each call in that module, as the rest should be the
1761 * same. Only search for a new one if the last one did
1762 * not match.
1763 */
1764 if (file_ops && mod == file_ops->mod)
1765 return file_ops;
1766
1767 list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1768 if (file_ops->mod == mod)
1769 return file_ops;
1770 }
1771 return NULL;
1772 }
1773
1774 static struct ftrace_module_file_ops *
1775 trace_create_file_ops(struct module *mod)
1776 {
1777 struct ftrace_module_file_ops *file_ops;
1778
1779 /*
1780 * This is a bit of a PITA. To allow for correct reference
1781 * counting, modules must "own" their file_operations.
1782 * To do this, we allocate the file operations that will be
1783 * used in the event directory.
1784 */
1785
1786 file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1787 if (!file_ops)
1788 return NULL;
1789
1790 file_ops->mod = mod;
1791
1792 file_ops->id = ftrace_event_id_fops;
1793 file_ops->id.owner = mod;
1794
1795 file_ops->enable = ftrace_enable_fops;
1796 file_ops->enable.owner = mod;
1797
1798 file_ops->filter = ftrace_event_filter_fops;
1799 file_ops->filter.owner = mod;
1800
1801 file_ops->format = ftrace_event_format_fops;
1802 file_ops->format.owner = mod;
1803
1804 list_add(&file_ops->list, &ftrace_module_file_list);
1805
1806 return file_ops;
1807 }
1808
1809 static void trace_module_add_events(struct module *mod)
1810 {
1811 struct ftrace_module_file_ops *file_ops = NULL;
1812 struct ftrace_event_call **call, **start, **end;
1813
1814 start = mod->trace_events;
1815 end = mod->trace_events + mod->num_trace_events;
1816
1817 if (start == end)
1818 return;
1819
1820 file_ops = trace_create_file_ops(mod);
1821 if (!file_ops)
1822 return;
1823
1824 for_each_event(call, start, end) {
1825 __register_event(*call, mod);
1826 __add_event_to_tracers(*call, file_ops);
1827 }
1828 }
1829
1830 static void trace_module_remove_events(struct module *mod)
1831 {
1832 struct ftrace_module_file_ops *file_ops;
1833 struct ftrace_event_call *call, *p;
1834 bool clear_trace = false;
1835
1836 down_write(&trace_event_sem);
1837 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1838 if (call->mod == mod) {
1839 if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
1840 clear_trace = true;
1841 __trace_remove_event_call(call);
1842 }
1843 }
1844
1845 /* Now free the file_operations */
1846 list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1847 if (file_ops->mod == mod)
1848 break;
1849 }
1850 if (&file_ops->list != &ftrace_module_file_list) {
1851 list_del(&file_ops->list);
1852 kfree(file_ops);
1853 }
1854 up_write(&trace_event_sem);
1855
1856 /*
1857 * It is safest to reset the ring buffer if the module being unloaded
1858 * registered any events that were used. The only worry is if
1859 * a new module gets loaded, and takes on the same id as the events
1860 * of this module. When printing out the buffer, traced events left
1861 * over from this module may be passed to the new module events and
1862 * unexpected results may occur.
1863 */
1864 if (clear_trace)
1865 tracing_reset_all_online_cpus();
1866 }
1867
1868 static int trace_module_notify(struct notifier_block *self,
1869 unsigned long val, void *data)
1870 {
1871 struct module *mod = data;
1872
1873 mutex_lock(&trace_types_lock);
1874 mutex_lock(&event_mutex);
1875 switch (val) {
1876 case MODULE_STATE_COMING:
1877 trace_module_add_events(mod);
1878 break;
1879 case MODULE_STATE_GOING:
1880 trace_module_remove_events(mod);
1881 break;
1882 }
1883 mutex_unlock(&event_mutex);
1884 mutex_unlock(&trace_types_lock);
1885
1886 return 0;
1887 }
1888
1889 static int
1890 __trace_add_new_mod_event(struct ftrace_event_call *call,
1891 struct trace_array *tr,
1892 struct ftrace_module_file_ops *file_ops)
1893 {
1894 return __trace_add_new_event(call, tr,
1895 &file_ops->id, &file_ops->enable,
1896 &file_ops->filter, &file_ops->format);
1897 }
1898
1899 #else
1900 static inline struct ftrace_module_file_ops *
1901 find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
1902 {
1903 return NULL;
1904 }
1905 static inline int trace_module_notify(struct notifier_block *self,
1906 unsigned long val, void *data)
1907 {
1908 return 0;
1909 }
1910 static inline int
1911 __trace_add_new_mod_event(struct ftrace_event_call *call,
1912 struct trace_array *tr,
1913 struct ftrace_module_file_ops *file_ops)
1914 {
1915 return -ENODEV;
1916 }
1917 #endif /* CONFIG_MODULES */
1918
1919 /* Create a new event directory structure for a trace directory. */
1920 static void
1921 __trace_add_event_dirs(struct trace_array *tr)
1922 {
1923 struct ftrace_module_file_ops *file_ops = NULL;
1924 struct ftrace_event_call *call;
1925 int ret;
1926
1927 list_for_each_entry(call, &ftrace_events, list) {
1928 if (call->mod) {
1929 /*
1930 * Directories for events by modules need to
1931 * keep module ref counts when opened (as we don't
1932 * want the module to disappear when reading one
1933 * of these files). The file_ops keep account of
1934 * the module ref count.
1935 */
1936 file_ops = find_ftrace_file_ops(file_ops, call->mod);
1937 if (!file_ops)
1938 continue; /* Warn? */
1939 ret = __trace_add_new_mod_event(call, tr, file_ops);
1940 if (ret < 0)
1941 pr_warning("Could not create directory for event %s\n",
1942 call->name);
1943 continue;
1944 }
1945 ret = __trace_add_new_event(call, tr,
1946 &ftrace_event_id_fops,
1947 &ftrace_enable_fops,
1948 &ftrace_event_filter_fops,
1949 &ftrace_event_format_fops);
1950 if (ret < 0)
1951 pr_warning("Could not create directory for event %s\n",
1952 call->name);
1953 }
1954 }
1955
1956 #ifdef CONFIG_DYNAMIC_FTRACE
1957
1958 /* Avoid typos */
1959 #define ENABLE_EVENT_STR "enable_event"
1960 #define DISABLE_EVENT_STR "disable_event"
1961
1962 struct event_probe_data {
1963 struct ftrace_event_file *file;
1964 unsigned long count;
1965 int ref;
1966 bool enable;
1967 };
1968
1969 static struct ftrace_event_file *
1970 find_event_file(struct trace_array *tr, const char *system, const char *event)
1971 {
1972 struct ftrace_event_file *file;
1973 struct ftrace_event_call *call;
1974
1975 list_for_each_entry(file, &tr->events, list) {
1976
1977 call = file->event_call;
1978
1979 if (!call->name || !call->class || !call->class->reg)
1980 continue;
1981
1982 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1983 continue;
1984
1985 if (strcmp(event, call->name) == 0 &&
1986 strcmp(system, call->class->system) == 0)
1987 return file;
1988 }
1989 return NULL;
1990 }
1991
1992 static void
1993 event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1994 {
1995 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1996 struct event_probe_data *data = *pdata;
1997
1998 if (!data)
1999 return;
2000
2001 if (data->enable)
2002 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
2003 else
2004 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
2005 }
2006
2007 static void
2008 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
2009 {
2010 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2011 struct event_probe_data *data = *pdata;
2012
2013 if (!data)
2014 return;
2015
2016 if (!data->count)
2017 return;
2018
2019 /* Skip if the event is in a state we want to switch to */
2020 if (data->enable == !(data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
2021 return;
2022
2023 if (data->count != -1)
2024 (data->count)--;
2025
2026 event_enable_probe(ip, parent_ip, _data);
2027 }
2028
2029 static int
2030 event_enable_print(struct seq_file *m, unsigned long ip,
2031 struct ftrace_probe_ops *ops, void *_data)
2032 {
2033 struct event_probe_data *data = _data;
2034
2035 seq_printf(m, "%ps:", (void *)ip);
2036
2037 seq_printf(m, "%s:%s:%s",
2038 data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
2039 data->file->event_call->class->system,
2040 data->file->event_call->name);
2041
2042 if (data->count == -1)
2043 seq_printf(m, ":unlimited\n");
2044 else
2045 seq_printf(m, ":count=%ld\n", data->count);
2046
2047 return 0;
2048 }
2049
2050 static int
2051 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
2052 void **_data)
2053 {
2054 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2055 struct event_probe_data *data = *pdata;
2056
2057 data->ref++;
2058 return 0;
2059 }
2060
2061 static void
2062 event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
2063 void **_data)
2064 {
2065 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2066 struct event_probe_data *data = *pdata;
2067
2068 if (WARN_ON_ONCE(data->ref <= 0))
2069 return;
2070
2071 data->ref--;
2072 if (!data->ref) {
2073 /* Remove the SOFT_MODE flag */
2074 __ftrace_event_enable_disable(data->file, 0, 1);
2075 module_put(data->file->event_call->mod);
2076 kfree(data);
2077 }
2078 *pdata = NULL;
2079 }
2080
2081 static struct ftrace_probe_ops event_enable_probe_ops = {
2082 .func = event_enable_probe,
2083 .print = event_enable_print,
2084 .init = event_enable_init,
2085 .free = event_enable_free,
2086 };
2087
2088 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2089 .func = event_enable_count_probe,
2090 .print = event_enable_print,
2091 .init = event_enable_init,
2092 .free = event_enable_free,
2093 };
2094
2095 static struct ftrace_probe_ops event_disable_probe_ops = {
2096 .func = event_enable_probe,
2097 .print = event_enable_print,
2098 .init = event_enable_init,
2099 .free = event_enable_free,
2100 };
2101
2102 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2103 .func = event_enable_count_probe,
2104 .print = event_enable_print,
2105 .init = event_enable_init,
2106 .free = event_enable_free,
2107 };
2108
2109 static int
2110 event_enable_func(struct ftrace_hash *hash,
2111 char *glob, char *cmd, char *param, int enabled)
2112 {
2113 struct trace_array *tr = top_trace_array();
2114 struct ftrace_event_file *file;
2115 struct ftrace_probe_ops *ops;
2116 struct event_probe_data *data;
2117 const char *system;
2118 const char *event;
2119 char *number;
2120 bool enable;
2121 int ret;
2122
2123 /* hash funcs only work with set_ftrace_filter */
2124 if (!enabled || !param)
2125 return -EINVAL;
2126
2127 system = strsep(&param, ":");
2128 if (!param)
2129 return -EINVAL;
2130
2131 event = strsep(&param, ":");
2132
2133 mutex_lock(&event_mutex);
2134
2135 ret = -EINVAL;
2136 file = find_event_file(tr, system, event);
2137 if (!file)
2138 goto out;
2139
2140 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2141
2142 if (enable)
2143 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2144 else
2145 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2146
2147 if (glob[0] == '!') {
2148 unregister_ftrace_function_probe_func(glob+1, ops);
2149 ret = 0;
2150 goto out;
2151 }
2152
2153 ret = -ENOMEM;
2154 data = kzalloc(sizeof(*data), GFP_KERNEL);
2155 if (!data)
2156 goto out;
2157
2158 data->enable = enable;
2159 data->count = -1;
2160 data->file = file;
2161
2162 if (!param)
2163 goto out_reg;
2164
2165 number = strsep(&param, ":");
2166
2167 ret = -EINVAL;
2168 if (!strlen(number))
2169 goto out_free;
2170
2171 /*
2172 * We use the callback data field (which is a pointer)
2173 * as our counter.
2174 */
2175 ret = kstrtoul(number, 0, &data->count);
2176 if (ret)
2177 goto out_free;
2178
2179 out_reg:
2180 /* Don't let event modules unload while probe registered */
2181 ret = try_module_get(file->event_call->mod);
2182 if (!ret) {
2183 ret = -EBUSY;
2184 goto out_free;
2185 }
2186
2187 ret = __ftrace_event_enable_disable(file, 1, 1);
2188 if (ret < 0)
2189 goto out_put;
2190 ret = register_ftrace_function_probe(glob, ops, data);
2191 /*
2192 * The above returns on success the # of functions enabled,
2193 * but if it didn't find any functions it returns zero.
2194 * Consider no functions a failure too.
2195 */
2196 if (!ret) {
2197 ret = -ENOENT;
2198 goto out_disable;
2199 } else if (ret < 0)
2200 goto out_disable;
2201 /* Just return zero, not the number of enabled functions */
2202 ret = 0;
2203 out:
2204 mutex_unlock(&event_mutex);
2205 return ret;
2206
2207 out_disable:
2208 __ftrace_event_enable_disable(file, 0, 1);
2209 out_put:
2210 module_put(file->event_call->mod);
2211 out_free:
2212 kfree(data);
2213 goto out;
2214 }
2215
2216 static struct ftrace_func_command event_enable_cmd = {
2217 .name = ENABLE_EVENT_STR,
2218 .func = event_enable_func,
2219 };
2220
2221 static struct ftrace_func_command event_disable_cmd = {
2222 .name = DISABLE_EVENT_STR,
2223 .func = event_enable_func,
2224 };
2225
2226 static __init int register_event_cmds(void)
2227 {
2228 int ret;
2229
2230 ret = register_ftrace_command(&event_enable_cmd);
2231 if (WARN_ON(ret < 0))
2232 return ret;
2233 ret = register_ftrace_command(&event_disable_cmd);
2234 if (WARN_ON(ret < 0))
2235 unregister_ftrace_command(&event_enable_cmd);
2236 return ret;
2237 }
2238 #else
2239 static inline int register_event_cmds(void) { return 0; }
2240 #endif /* CONFIG_DYNAMIC_FTRACE */
2241
2242 /*
2243 * The top level array has already had its ftrace_event_file
2244 * descriptors created in order to allow for early events to
2245 * be recorded. This function is called after the debugfs has been
2246 * initialized, and we now have to create the files associated
2247 * to the events.
2248 */
2249 static __init void
2250 __trace_early_add_event_dirs(struct trace_array *tr)
2251 {
2252 struct ftrace_event_file *file;
2253 int ret;
2254
2255
2256 list_for_each_entry(file, &tr->events, list) {
2257 ret = event_create_dir(tr->event_dir, file,
2258 &ftrace_event_id_fops,
2259 &ftrace_enable_fops,
2260 &ftrace_event_filter_fops,
2261 &ftrace_event_format_fops);
2262 if (ret < 0)
2263 pr_warning("Could not create directory for event %s\n",
2264 file->event_call->name);
2265 }
2266 }
2267
2268 /*
2269 * For early boot up, the top trace array requires to have
2270 * a list of events that can be enabled. This must be done before
2271 * the filesystem is set up in order to allow events to be traced
2272 * early.
2273 */
2274 static __init void
2275 __trace_early_add_events(struct trace_array *tr)
2276 {
2277 struct ftrace_event_call *call;
2278 int ret;
2279
2280 list_for_each_entry(call, &ftrace_events, list) {
2281 /* Early boot up should not have any modules loaded */
2282 if (WARN_ON_ONCE(call->mod))
2283 continue;
2284
2285 ret = __trace_early_add_new_event(call, tr);
2286 if (ret < 0)
2287 pr_warning("Could not create early event %s\n",
2288 call->name);
2289 }
2290 }
2291
2292 /* Remove the event directory structure for a trace directory. */
2293 static void
2294 __trace_remove_event_dirs(struct trace_array *tr)
2295 {
2296 struct ftrace_event_file *file, *next;
2297
2298 list_for_each_entry_safe(file, next, &tr->events, list) {
2299 list_del(&file->list);
2300 debugfs_remove_recursive(file->dir);
2301 remove_subsystem(file->system);
2302 kmem_cache_free(file_cachep, file);
2303 }
2304 }
2305
2306 static void
2307 __add_event_to_tracers(struct ftrace_event_call *call,
2308 struct ftrace_module_file_ops *file_ops)
2309 {
2310 struct trace_array *tr;
2311
2312 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2313 if (file_ops)
2314 __trace_add_new_mod_event(call, tr, file_ops);
2315 else
2316 __trace_add_new_event(call, tr,
2317 &ftrace_event_id_fops,
2318 &ftrace_enable_fops,
2319 &ftrace_event_filter_fops,
2320 &ftrace_event_format_fops);
2321 }
2322 }
2323
2324 static struct notifier_block trace_module_nb = {
2325 .notifier_call = trace_module_notify,
2326 .priority = 0,
2327 };
2328
2329 extern struct ftrace_event_call *__start_ftrace_events[];
2330 extern struct ftrace_event_call *__stop_ftrace_events[];
2331
2332 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2333
2334 static __init int setup_trace_event(char *str)
2335 {
2336 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2337 ring_buffer_expanded = true;
2338 tracing_selftest_disabled = true;
2339
2340 return 1;
2341 }
2342 __setup("trace_event=", setup_trace_event);
2343
2344 /* Expects to have event_mutex held when called */
2345 static int
2346 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2347 {
2348 struct dentry *d_events;
2349 struct dentry *entry;
2350
2351 entry = debugfs_create_file("set_event", 0644, parent,
2352 tr, &ftrace_set_event_fops);
2353 if (!entry) {
2354 pr_warning("Could not create debugfs 'set_event' entry\n");
2355 return -ENOMEM;
2356 }
2357
2358 d_events = debugfs_create_dir("events", parent);
2359 if (!d_events) {
2360 pr_warning("Could not create debugfs 'events' directory\n");
2361 return -ENOMEM;
2362 }
2363
2364 /* ring buffer internal formats */
2365 trace_create_file("header_page", 0444, d_events,
2366 ring_buffer_print_page_header,
2367 &ftrace_show_header_fops);
2368
2369 trace_create_file("header_event", 0444, d_events,
2370 ring_buffer_print_entry_header,
2371 &ftrace_show_header_fops);
2372
2373 trace_create_file("enable", 0644, d_events,
2374 tr, &ftrace_tr_enable_fops);
2375
2376 tr->event_dir = d_events;
2377
2378 return 0;
2379 }
2380
2381 /**
2382 * event_trace_add_tracer - add a instance of a trace_array to events
2383 * @parent: The parent dentry to place the files/directories for events in
2384 * @tr: The trace array associated with these events
2385 *
2386 * When a new instance is created, it needs to set up its events
2387 * directory, as well as other files associated with events. It also
2388 * creates the event hierachry in the @parent/events directory.
2389 *
2390 * Returns 0 on success.
2391 */
2392 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2393 {
2394 int ret;
2395
2396 mutex_lock(&event_mutex);
2397
2398 ret = create_event_toplevel_files(parent, tr);
2399 if (ret)
2400 goto out_unlock;
2401
2402 down_write(&trace_event_sem);
2403 __trace_add_event_dirs(tr);
2404 up_write(&trace_event_sem);
2405
2406 out_unlock:
2407 mutex_unlock(&event_mutex);
2408
2409 return ret;
2410 }
2411
2412 /*
2413 * The top trace array already had its file descriptors created.
2414 * Now the files themselves need to be created.
2415 */
2416 static __init int
2417 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2418 {
2419 int ret;
2420
2421 mutex_lock(&event_mutex);
2422
2423 ret = create_event_toplevel_files(parent, tr);
2424 if (ret)
2425 goto out_unlock;
2426
2427 down_write(&trace_event_sem);
2428 __trace_early_add_event_dirs(tr);
2429 up_write(&trace_event_sem);
2430
2431 out_unlock:
2432 mutex_unlock(&event_mutex);
2433
2434 return ret;
2435 }
2436
2437 int event_trace_del_tracer(struct trace_array *tr)
2438 {
2439 mutex_lock(&event_mutex);
2440
2441 /* Disable any running events */
2442 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
2443
2444 down_write(&trace_event_sem);
2445 __trace_remove_event_dirs(tr);
2446 debugfs_remove_recursive(tr->event_dir);
2447 up_write(&trace_event_sem);
2448
2449 tr->event_dir = NULL;
2450
2451 mutex_unlock(&event_mutex);
2452
2453 return 0;
2454 }
2455
2456 static __init int event_trace_memsetup(void)
2457 {
2458 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
2459 file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC);
2460 return 0;
2461 }
2462
2463 static __init int event_trace_enable(void)
2464 {
2465 struct trace_array *tr = top_trace_array();
2466 struct ftrace_event_call **iter, *call;
2467 char *buf = bootup_event_buf;
2468 char *token;
2469 int ret;
2470
2471 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
2472
2473 call = *iter;
2474 ret = event_init(call);
2475 if (!ret)
2476 list_add(&call->list, &ftrace_events);
2477 }
2478
2479 /*
2480 * We need the top trace array to have a working set of trace
2481 * points at early init, before the debug files and directories
2482 * are created. Create the file entries now, and attach them
2483 * to the actual file dentries later.
2484 */
2485 __trace_early_add_events(tr);
2486
2487 while (true) {
2488 token = strsep(&buf, ",");
2489
2490 if (!token)
2491 break;
2492 if (!*token)
2493 continue;
2494
2495 ret = ftrace_set_clr_event(tr, token, 1);
2496 if (ret)
2497 pr_warn("Failed to enable trace event: %s\n", token);
2498 }
2499
2500 trace_printk_start_comm();
2501
2502 register_event_cmds();
2503
2504 return 0;
2505 }
2506
2507 static __init int event_trace_init(void)
2508 {
2509 struct trace_array *tr;
2510 struct dentry *d_tracer;
2511 struct dentry *entry;
2512 int ret;
2513
2514 tr = top_trace_array();
2515
2516 d_tracer = tracing_init_dentry();
2517 if (!d_tracer)
2518 return 0;
2519
2520 entry = debugfs_create_file("available_events", 0444, d_tracer,
2521 tr, &ftrace_avail_fops);
2522 if (!entry)
2523 pr_warning("Could not create debugfs "
2524 "'available_events' entry\n");
2525
2526 if (trace_define_common_fields())
2527 pr_warning("tracing: Failed to allocate common fields");
2528
2529 ret = early_event_add_tracer(d_tracer, tr);
2530 if (ret)
2531 return ret;
2532
2533 ret = register_module_notifier(&trace_module_nb);
2534 if (ret)
2535 pr_warning("Failed to register trace events module notifier\n");
2536
2537 return 0;
2538 }
2539 early_initcall(event_trace_memsetup);
2540 core_initcall(event_trace_enable);
2541 fs_initcall(event_trace_init);
2542
2543 #ifdef CONFIG_FTRACE_STARTUP_TEST
2544
2545 static DEFINE_SPINLOCK(test_spinlock);
2546 static DEFINE_SPINLOCK(test_spinlock_irq);
2547 static DEFINE_MUTEX(test_mutex);
2548
2549 static __init void test_work(struct work_struct *dummy)
2550 {
2551 spin_lock(&test_spinlock);
2552 spin_lock_irq(&test_spinlock_irq);
2553 udelay(1);
2554 spin_unlock_irq(&test_spinlock_irq);
2555 spin_unlock(&test_spinlock);
2556
2557 mutex_lock(&test_mutex);
2558 msleep(1);
2559 mutex_unlock(&test_mutex);
2560 }
2561
2562 static __init int event_test_thread(void *unused)
2563 {
2564 void *test_malloc;
2565
2566 test_malloc = kmalloc(1234, GFP_KERNEL);
2567 if (!test_malloc)
2568 pr_info("failed to kmalloc\n");
2569
2570 schedule_on_each_cpu(test_work);
2571
2572 kfree(test_malloc);
2573
2574 set_current_state(TASK_INTERRUPTIBLE);
2575 while (!kthread_should_stop())
2576 schedule();
2577
2578 return 0;
2579 }
2580
2581 /*
2582 * Do various things that may trigger events.
2583 */
2584 static __init void event_test_stuff(void)
2585 {
2586 struct task_struct *test_thread;
2587
2588 test_thread = kthread_run(event_test_thread, NULL, "test-events");
2589 msleep(1);
2590 kthread_stop(test_thread);
2591 }
2592
2593 /*
2594 * For every trace event defined, we will test each trace point separately,
2595 * and then by groups, and finally all trace points.
2596 */
2597 static __init void event_trace_self_tests(void)
2598 {
2599 struct ftrace_subsystem_dir *dir;
2600 struct ftrace_event_file *file;
2601 struct ftrace_event_call *call;
2602 struct event_subsystem *system;
2603 struct trace_array *tr;
2604 int ret;
2605
2606 tr = top_trace_array();
2607
2608 pr_info("Running tests on trace events:\n");
2609
2610 list_for_each_entry(file, &tr->events, list) {
2611
2612 call = file->event_call;
2613
2614 /* Only test those that have a probe */
2615 if (!call->class || !call->class->probe)
2616 continue;
2617
2618 /*
2619 * Testing syscall events here is pretty useless, but
2620 * we still do it if configured. But this is time consuming.
2621 * What we really need is a user thread to perform the
2622 * syscalls as we test.
2623 */
2624 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
2625 if (call->class->system &&
2626 strcmp(call->class->system, "syscalls") == 0)
2627 continue;
2628 #endif
2629
2630 pr_info("Testing event %s: ", call->name);
2631
2632 /*
2633 * If an event is already enabled, someone is using
2634 * it and the self test should not be on.
2635 */
2636 if (file->flags & FTRACE_EVENT_FL_ENABLED) {
2637 pr_warning("Enabled event during self test!\n");
2638 WARN_ON_ONCE(1);
2639 continue;
2640 }
2641
2642 ftrace_event_enable_disable(file, 1);
2643 event_test_stuff();
2644 ftrace_event_enable_disable(file, 0);
2645
2646 pr_cont("OK\n");
2647 }
2648
2649 /* Now test at the sub system level */
2650
2651 pr_info("Running tests on trace event systems:\n");
2652
2653 list_for_each_entry(dir, &tr->systems, list) {
2654
2655 system = dir->subsystem;
2656
2657 /* the ftrace system is special, skip it */
2658 if (strcmp(system->name, "ftrace") == 0)
2659 continue;
2660
2661 pr_info("Testing event system %s: ", system->name);
2662
2663 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
2664 if (WARN_ON_ONCE(ret)) {
2665 pr_warning("error enabling system %s\n",
2666 system->name);
2667 continue;
2668 }
2669
2670 event_test_stuff();
2671
2672 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
2673 if (WARN_ON_ONCE(ret)) {
2674 pr_warning("error disabling system %s\n",
2675 system->name);
2676 continue;
2677 }
2678
2679 pr_cont("OK\n");
2680 }
2681
2682 /* Test with all events enabled */
2683
2684 pr_info("Running tests on all trace events:\n");
2685 pr_info("Testing all events: ");
2686
2687 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
2688 if (WARN_ON_ONCE(ret)) {
2689 pr_warning("error enabling all events\n");
2690 return;
2691 }
2692
2693 event_test_stuff();
2694
2695 /* reset sysname */
2696 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
2697 if (WARN_ON_ONCE(ret)) {
2698 pr_warning("error disabling all events\n");
2699 return;
2700 }
2701
2702 pr_cont("OK\n");
2703 }
2704
2705 #ifdef CONFIG_FUNCTION_TRACER
2706
2707 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
2708
2709 static void
2710 function_test_events_call(unsigned long ip, unsigned long parent_ip,
2711 struct ftrace_ops *op, struct pt_regs *pt_regs)
2712 {
2713 struct ring_buffer_event *event;
2714 struct ring_buffer *buffer;
2715 struct ftrace_entry *entry;
2716 unsigned long flags;
2717 long disabled;
2718 int cpu;
2719 int pc;
2720
2721 pc = preempt_count();
2722 preempt_disable_notrace();
2723 cpu = raw_smp_processor_id();
2724 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
2725
2726 if (disabled != 1)
2727 goto out;
2728
2729 local_save_flags(flags);
2730
2731 event = trace_current_buffer_lock_reserve(&buffer,
2732 TRACE_FN, sizeof(*entry),
2733 flags, pc);
2734 if (!event)
2735 goto out;
2736 entry = ring_buffer_event_data(event);
2737 entry->ip = ip;
2738 entry->parent_ip = parent_ip;
2739
2740 trace_buffer_unlock_commit(buffer, event, flags, pc);
2741
2742 out:
2743 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
2744 preempt_enable_notrace();
2745 }
2746
2747 static struct ftrace_ops trace_ops __initdata =
2748 {
2749 .func = function_test_events_call,
2750 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
2751 };
2752
2753 static __init void event_trace_self_test_with_function(void)
2754 {
2755 int ret;
2756 ret = register_ftrace_function(&trace_ops);
2757 if (WARN_ON(ret < 0)) {
2758 pr_info("Failed to enable function tracer for event tests\n");
2759 return;
2760 }
2761 pr_info("Running tests again, along with the function tracer\n");
2762 event_trace_self_tests();
2763 unregister_ftrace_function(&trace_ops);
2764 }
2765 #else
2766 static __init void event_trace_self_test_with_function(void)
2767 {
2768 }
2769 #endif
2770
2771 static __init int event_trace_self_tests_init(void)
2772 {
2773 if (!tracing_selftest_disabled) {
2774 event_trace_self_tests();
2775 event_trace_self_test_with_function();
2776 }
2777
2778 return 0;
2779 }
2780
2781 late_initcall(event_trace_self_tests_init);
2782
2783 #endif
Linux kernel - Deliverables
This page took 0.086161 seconds and 4 git commands to generate.