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[media] media: vb2: Share code between vb2_prepare_buf and vb2_qbuf
[linux-2.6.git] / kernel / trace / trace_events.c
blob7d854290bf817ef8c6b116b031830dc060ae5dc7
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
1222 static const struct seq_operations show_event_seq_ops = {
1223 .start = t_start,
1224 .next = t_next,
1225 .show = t_show,
1226 .stop = t_stop,
1227 };
1228
1229 static const struct seq_operations show_set_event_seq_ops = {
1230 .start = s_start,
1231 .next = s_next,
1232 .show = t_show,
1233 .stop = t_stop,
1234 };
1235
1236 static const struct file_operations ftrace_avail_fops = {
1237 .open = ftrace_event_avail_open,
1238 .read = seq_read,
1239 .llseek = seq_lseek,
1240 .release = seq_release,
1241 };
1242
1243 static const struct file_operations ftrace_set_event_fops = {
1244 .open = ftrace_event_set_open,
1245 .read = seq_read,
1246 .write = ftrace_event_write,
1247 .llseek = seq_lseek,
1248 .release = seq_release,
1249 };
1250
1251 static const struct file_operations ftrace_enable_fops = {
1252 .open = tracing_open_generic_file,
1253 .read = event_enable_read,
1254 .write = event_enable_write,
1255 .release = tracing_release_generic_file,
1256 .llseek = default_llseek,
1257 };
1258
1259 static const struct file_operations ftrace_event_format_fops = {
1260 .open = trace_format_open,
1261 .read = seq_read,
1262 .llseek = seq_lseek,
1263 .release = seq_release,
1264 };
1265
1266 static const struct file_operations ftrace_event_id_fops = {
1267 .open = tracing_open_generic,
1268 .read = event_id_read,
1269 .llseek = default_llseek,
1270 };
1271
1272 static const struct file_operations ftrace_event_filter_fops = {
1273 .open = tracing_open_generic,
1274 .read = event_filter_read,
1275 .write = event_filter_write,
1276 .llseek = default_llseek,
1277 };
1278
1279 static const struct file_operations ftrace_subsystem_filter_fops = {
1280 .open = subsystem_open,
1281 .read = subsystem_filter_read,
1282 .write = subsystem_filter_write,
1283 .llseek = default_llseek,
1284 .release = subsystem_release,
1285 };
1286
1287 static const struct file_operations ftrace_system_enable_fops = {
1288 .open = subsystem_open,
1289 .read = system_enable_read,
1290 .write = system_enable_write,
1291 .llseek = default_llseek,
1292 .release = subsystem_release,
1293 };
1294
1295 static const struct file_operations ftrace_tr_enable_fops = {
1296 .open = system_tr_open,
1297 .read = system_enable_read,
1298 .write = system_enable_write,
1299 .llseek = default_llseek,
1300 .release = subsystem_release,
1301 };
1302
1303 static const struct file_operations ftrace_show_header_fops = {
1304 .open = tracing_open_generic,
1305 .read = show_header,
1306 .llseek = default_llseek,
1307 };
1308
1309 static int
1310 ftrace_event_open(struct inode *inode, struct file *file,
1311 const struct seq_operations *seq_ops)
1312 {
1313 struct seq_file *m;
1314 int ret;
1315
1316 ret = seq_open(file, seq_ops);
1317 if (ret < 0)
1318 return ret;
1319 m = file->private_data;
1320 /* copy tr over to seq ops */
1321 m->private = inode->i_private;
1322
1323 return ret;
1324 }
1325
1326 static int
1327 ftrace_event_avail_open(struct inode *inode, struct file *file)
1328 {
1329 const struct seq_operations *seq_ops = &show_event_seq_ops;
1330
1331 return ftrace_event_open(inode, file, seq_ops);
1332 }
1333
1334 static int
1335 ftrace_event_set_open(struct inode *inode, struct file *file)
1336 {
1337 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1338 struct trace_array *tr = inode->i_private;
1339
1340 if ((file->f_mode & FMODE_WRITE) &&
1341 (file->f_flags & O_TRUNC))
1342 ftrace_clear_events(tr);
1343
1344 return ftrace_event_open(inode, file, seq_ops);
1345 }
1346
1347 static struct event_subsystem *
1348 create_new_subsystem(const char *name)
1349 {
1350 struct event_subsystem *system;
1351
1352 /* need to create new entry */
1353 system = kmalloc(sizeof(*system), GFP_KERNEL);
1354 if (!system)
1355 return NULL;
1356
1357 system->ref_count = 1;
1358
1359 /* Only allocate if dynamic (kprobes and modules) */
1360 if (!core_kernel_data((unsigned long)name)) {
1361 system->ref_count |= SYSTEM_FL_FREE_NAME;
1362 system->name = kstrdup(name, GFP_KERNEL);
1363 if (!system->name)
1364 goto out_free;
1365 } else
1366 system->name = name;
1367
1368 system->filter = NULL;
1369
1370 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1371 if (!system->filter)
1372 goto out_free;
1373
1374 list_add(&system->list, &event_subsystems);
1375
1376 return system;
1377
1378 out_free:
1379 if (system->ref_count & SYSTEM_FL_FREE_NAME)
1380 kfree(system->name);
1381 kfree(system);
1382 return NULL;
1383 }
1384
1385 static struct dentry *
1386 event_subsystem_dir(struct trace_array *tr, const char *name,
1387 struct ftrace_event_file *file, struct dentry *parent)
1388 {
1389 struct ftrace_subsystem_dir *dir;
1390 struct event_subsystem *system;
1391 struct dentry *entry;
1392
1393 /* First see if we did not already create this dir */
1394 list_for_each_entry(dir, &tr->systems, list) {
1395 system = dir->subsystem;
1396 if (strcmp(system->name, name) == 0) {
1397 dir->nr_events++;
1398 file->system = dir;
1399 return dir->entry;
1400 }
1401 }
1402
1403 /* Now see if the system itself exists. */
1404 list_for_each_entry(system, &event_subsystems, list) {
1405 if (strcmp(system->name, name) == 0)
1406 break;
1407 }
1408 /* Reset system variable when not found */
1409 if (&system->list == &event_subsystems)
1410 system = NULL;
1411
1412 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1413 if (!dir)
1414 goto out_fail;
1415
1416 if (!system) {
1417 system = create_new_subsystem(name);
1418 if (!system)
1419 goto out_free;
1420 } else
1421 __get_system(system);
1422
1423 dir->entry = debugfs_create_dir(name, parent);
1424 if (!dir->entry) {
1425 pr_warning("Failed to create system directory %s\n", name);
1426 __put_system(system);
1427 goto out_free;
1428 }
1429
1430 dir->tr = tr;
1431 dir->ref_count = 1;
1432 dir->nr_events = 1;
1433 dir->subsystem = system;
1434 file->system = dir;
1435
1436 entry = debugfs_create_file("filter", 0644, dir->entry, dir,
1437 &ftrace_subsystem_filter_fops);
1438 if (!entry) {
1439 kfree(system->filter);
1440 system->filter = NULL;
1441 pr_warning("Could not create debugfs '%s/filter' entry\n", name);
1442 }
1443
1444 trace_create_file("enable", 0644, dir->entry, dir,
1445 &ftrace_system_enable_fops);
1446
1447 list_add(&dir->list, &tr->systems);
1448
1449 return dir->entry;
1450
1451 out_free:
1452 kfree(dir);
1453 out_fail:
1454 /* Only print this message if failed on memory allocation */
1455 if (!dir || !system)
1456 pr_warning("No memory to create event subsystem %s\n",
1457 name);
1458 return NULL;
1459 }
1460
1461 static int
1462 event_create_dir(struct dentry *parent,
1463 struct ftrace_event_file *file,
1464 const struct file_operations *id,
1465 const struct file_operations *enable,
1466 const struct file_operations *filter,
1467 const struct file_operations *format)
1468 {
1469 struct ftrace_event_call *call = file->event_call;
1470 struct trace_array *tr = file->tr;
1471 struct list_head *head;
1472 struct dentry *d_events;
1473 int ret;
1474
1475 /*
1476 * If the trace point header did not define TRACE_SYSTEM
1477 * then the system would be called "TRACE_SYSTEM".
1478 */
1479 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1480 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1481 if (!d_events)
1482 return -ENOMEM;
1483 } else
1484 d_events = parent;
1485
1486 file->dir = debugfs_create_dir(call->name, d_events);
1487 if (!file->dir) {
1488 pr_warning("Could not create debugfs '%s' directory\n",
1489 call->name);
1490 return -1;
1491 }
1492
1493 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1494 trace_create_file("enable", 0644, file->dir, file,
1495 enable);
1496
1497 #ifdef CONFIG_PERF_EVENTS
1498 if (call->event.type && call->class->reg)
1499 trace_create_file("id", 0444, file->dir, call,
1500 id);
1501 #endif
1502
1503 /*
1504 * Other events may have the same class. Only update
1505 * the fields if they are not already defined.
1506 */
1507 head = trace_get_fields(call);
1508 if (list_empty(head)) {
1509 ret = call->class->define_fields(call);
1510 if (ret < 0) {
1511 pr_warning("Could not initialize trace point"
1512 " events/%s\n", call->name);
1513 return -1;
1514 }
1515 }
1516 trace_create_file("filter", 0644, file->dir, call,
1517 filter);
1518
1519 trace_create_file("format", 0444, file->dir, call,
1520 format);
1521
1522 return 0;
1523 }
1524
1525 static void remove_subsystem(struct ftrace_subsystem_dir *dir)
1526 {
1527 if (!dir)
1528 return;
1529
1530 if (!--dir->nr_events) {
1531 debugfs_remove_recursive(dir->entry);
1532 list_del(&dir->list);
1533 __put_system_dir(dir);
1534 }
1535 }
1536
1537 static void remove_event_from_tracers(struct ftrace_event_call *call)
1538 {
1539 struct ftrace_event_file *file;
1540 struct trace_array *tr;
1541
1542 do_for_each_event_file_safe(tr, file) {
1543
1544 if (file->event_call != call)
1545 continue;
1546
1547 list_del(&file->list);
1548 debugfs_remove_recursive(file->dir);
1549 remove_subsystem(file->system);
1550 kmem_cache_free(file_cachep, file);
1551
1552 /*
1553 * The do_for_each_event_file_safe() is
1554 * a double loop. After finding the call for this
1555 * trace_array, we use break to jump to the next
1556 * trace_array.
1557 */
1558 break;
1559 } while_for_each_event_file();
1560 }
1561
1562 static void event_remove(struct ftrace_event_call *call)
1563 {
1564 struct trace_array *tr;
1565 struct ftrace_event_file *file;
1566
1567 do_for_each_event_file(tr, file) {
1568 if (file->event_call != call)
1569 continue;
1570 ftrace_event_enable_disable(file, 0);
1571 /*
1572 * The do_for_each_event_file() is
1573 * a double loop. After finding the call for this
1574 * trace_array, we use break to jump to the next
1575 * trace_array.
1576 */
1577 break;
1578 } while_for_each_event_file();
1579
1580 if (call->event.funcs)
1581 __unregister_ftrace_event(&call->event);
1582 remove_event_from_tracers(call);
1583 list_del(&call->list);
1584 }
1585
1586 static int event_init(struct ftrace_event_call *call)
1587 {
1588 int ret = 0;
1589
1590 if (WARN_ON(!call->name))
1591 return -EINVAL;
1592
1593 if (call->class->raw_init) {
1594 ret = call->class->raw_init(call);
1595 if (ret < 0 && ret != -ENOSYS)
1596 pr_warn("Could not initialize trace events/%s\n",
1597 call->name);
1598 }
1599
1600 return ret;
1601 }
1602
1603 static int
1604 __register_event(struct ftrace_event_call *call, struct module *mod)
1605 {
1606 int ret;
1607
1608 ret = event_init(call);
1609 if (ret < 0)
1610 return ret;
1611
1612 list_add(&call->list, &ftrace_events);
1613 call->mod = mod;
1614
1615 return 0;
1616 }
1617
1618 static struct ftrace_event_file *
1619 trace_create_new_event(struct ftrace_event_call *call,
1620 struct trace_array *tr)
1621 {
1622 struct ftrace_event_file *file;
1623
1624 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
1625 if (!file)
1626 return NULL;
1627
1628 file->event_call = call;
1629 file->tr = tr;
1630 atomic_set(&file->sm_ref, 0);
1631 list_add(&file->list, &tr->events);
1632
1633 return file;
1634 }
1635
1636 /* Add an event to a trace directory */
1637 static int
1638 __trace_add_new_event(struct ftrace_event_call *call,
1639 struct trace_array *tr,
1640 const struct file_operations *id,
1641 const struct file_operations *enable,
1642 const struct file_operations *filter,
1643 const struct file_operations *format)
1644 {
1645 struct ftrace_event_file *file;
1646
1647 file = trace_create_new_event(call, tr);
1648 if (!file)
1649 return -ENOMEM;
1650
1651 return event_create_dir(tr->event_dir, file, id, enable, filter, format);
1652 }
1653
1654 /*
1655 * Just create a decriptor for early init. A descriptor is required
1656 * for enabling events at boot. We want to enable events before
1657 * the filesystem is initialized.
1658 */
1659 static __init int
1660 __trace_early_add_new_event(struct ftrace_event_call *call,
1661 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 0;
1670 }
1671
1672 struct ftrace_module_file_ops;
1673 static void __add_event_to_tracers(struct ftrace_event_call *call,
1674 struct ftrace_module_file_ops *file_ops);
1675
1676 /* Add an additional event_call dynamically */
1677 int trace_add_event_call(struct ftrace_event_call *call)
1678 {
1679 int ret;
1680 mutex_lock(&trace_types_lock);
1681 mutex_lock(&event_mutex);
1682
1683 ret = __register_event(call, NULL);
1684 if (ret >= 0)
1685 __add_event_to_tracers(call, NULL);
1686
1687 mutex_unlock(&event_mutex);
1688 mutex_unlock(&trace_types_lock);
1689 return ret;
1690 }
1691
1692 /*
1693 * Must be called under locking of trace_types_lock, event_mutex and
1694 * trace_event_sem.
1695 */
1696 static void __trace_remove_event_call(struct ftrace_event_call *call)
1697 {
1698 event_remove(call);
1699 trace_destroy_fields(call);
1700 destroy_preds(call);
1701 }
1702
1703 /* Remove an event_call */
1704 void trace_remove_event_call(struct ftrace_event_call *call)
1705 {
1706 mutex_lock(&trace_types_lock);
1707 mutex_lock(&event_mutex);
1708 down_write(&trace_event_sem);
1709 __trace_remove_event_call(call);
1710 up_write(&trace_event_sem);
1711 mutex_unlock(&event_mutex);
1712 mutex_unlock(&trace_types_lock);
1713 }
1714
1715 #define for_each_event(event, start, end) \
1716 for (event = start; \
1717 (unsigned long)event < (unsigned long)end; \
1718 event++)
1719
1720 #ifdef CONFIG_MODULES
1721
1722 static LIST_HEAD(ftrace_module_file_list);
1723
1724 /*
1725 * Modules must own their file_operations to keep up with
1726 * reference counting.
1727 */
1728 struct ftrace_module_file_ops {
1729 struct list_head list;
1730 struct module *mod;
1731 struct file_operations id;
1732 struct file_operations enable;
1733 struct file_operations format;
1734 struct file_operations filter;
1735 };
1736
1737 static struct ftrace_module_file_ops *
1738 find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
1739 {
1740 /*
1741 * As event_calls are added in groups by module,
1742 * when we find one file_ops, we don't need to search for
1743 * each call in that module, as the rest should be the
1744 * same. Only search for a new one if the last one did
1745 * not match.
1746 */
1747 if (file_ops && mod == file_ops->mod)
1748 return file_ops;
1749
1750 list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1751 if (file_ops->mod == mod)
1752 return file_ops;
1753 }
1754 return NULL;
1755 }
1756
1757 static struct ftrace_module_file_ops *
1758 trace_create_file_ops(struct module *mod)
1759 {
1760 struct ftrace_module_file_ops *file_ops;
1761
1762 /*
1763 * This is a bit of a PITA. To allow for correct reference
1764 * counting, modules must "own" their file_operations.
1765 * To do this, we allocate the file operations that will be
1766 * used in the event directory.
1767 */
1768
1769 file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1770 if (!file_ops)
1771 return NULL;
1772
1773 file_ops->mod = mod;
1774
1775 file_ops->id = ftrace_event_id_fops;
1776 file_ops->id.owner = mod;
1777
1778 file_ops->enable = ftrace_enable_fops;
1779 file_ops->enable.owner = mod;
1780
1781 file_ops->filter = ftrace_event_filter_fops;
1782 file_ops->filter.owner = mod;
1783
1784 file_ops->format = ftrace_event_format_fops;
1785 file_ops->format.owner = mod;
1786
1787 list_add(&file_ops->list, &ftrace_module_file_list);
1788
1789 return file_ops;
1790 }
1791
1792 static void trace_module_add_events(struct module *mod)
1793 {
1794 struct ftrace_module_file_ops *file_ops = NULL;
1795 struct ftrace_event_call **call, **start, **end;
1796
1797 start = mod->trace_events;
1798 end = mod->trace_events + mod->num_trace_events;
1799
1800 if (start == end)
1801 return;
1802
1803 file_ops = trace_create_file_ops(mod);
1804 if (!file_ops)
1805 return;
1806
1807 for_each_event(call, start, end) {
1808 __register_event(*call, mod);
1809 __add_event_to_tracers(*call, file_ops);
1810 }
1811 }
1812
1813 static void trace_module_remove_events(struct module *mod)
1814 {
1815 struct ftrace_module_file_ops *file_ops;
1816 struct ftrace_event_call *call, *p;
1817 bool clear_trace = false;
1818
1819 down_write(&trace_event_sem);
1820 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1821 if (call->mod == mod) {
1822 if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
1823 clear_trace = true;
1824 __trace_remove_event_call(call);
1825 }
1826 }
1827
1828 /* Now free the file_operations */
1829 list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1830 if (file_ops->mod == mod)
1831 break;
1832 }
1833 if (&file_ops->list != &ftrace_module_file_list) {
1834 list_del(&file_ops->list);
1835 kfree(file_ops);
1836 }
1837 up_write(&trace_event_sem);
1838
1839 /*
1840 * It is safest to reset the ring buffer if the module being unloaded
1841 * registered any events that were used. The only worry is if
1842 * a new module gets loaded, and takes on the same id as the events
1843 * of this module. When printing out the buffer, traced events left
1844 * over from this module may be passed to the new module events and
1845 * unexpected results may occur.
1846 */
1847 if (clear_trace)
1848 tracing_reset_all_online_cpus();
1849 }
1850
1851 static int trace_module_notify(struct notifier_block *self,
1852 unsigned long val, void *data)
1853 {
1854 struct module *mod = data;
1855
1856 mutex_lock(&trace_types_lock);
1857 mutex_lock(&event_mutex);
1858 switch (val) {
1859 case MODULE_STATE_COMING:
1860 trace_module_add_events(mod);
1861 break;
1862 case MODULE_STATE_GOING:
1863 trace_module_remove_events(mod);
1864 break;
1865 }
1866 mutex_unlock(&event_mutex);
1867 mutex_unlock(&trace_types_lock);
1868
1869 return 0;
1870 }
1871
1872 static int
1873 __trace_add_new_mod_event(struct ftrace_event_call *call,
1874 struct trace_array *tr,
1875 struct ftrace_module_file_ops *file_ops)
1876 {
1877 return __trace_add_new_event(call, tr,
1878 &file_ops->id, &file_ops->enable,
1879 &file_ops->filter, &file_ops->format);
1880 }
1881
1882 #else
1883 static inline struct ftrace_module_file_ops *
1884 find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
1885 {
1886 return NULL;
1887 }
1888 static inline int trace_module_notify(struct notifier_block *self,
1889 unsigned long val, void *data)
1890 {
1891 return 0;
1892 }
1893 static inline int
1894 __trace_add_new_mod_event(struct ftrace_event_call *call,
1895 struct trace_array *tr,
1896 struct ftrace_module_file_ops *file_ops)
1897 {
1898 return -ENODEV;
1899 }
1900 #endif /* CONFIG_MODULES */
1901
1902 /* Create a new event directory structure for a trace directory. */
1903 static void
1904 __trace_add_event_dirs(struct trace_array *tr)
1905 {
1906 struct ftrace_module_file_ops *file_ops = NULL;
1907 struct ftrace_event_call *call;
1908 int ret;
1909
1910 list_for_each_entry(call, &ftrace_events, list) {
1911 if (call->mod) {
1912 /*
1913 * Directories for events by modules need to
1914 * keep module ref counts when opened (as we don't
1915 * want the module to disappear when reading one
1916 * of these files). The file_ops keep account of
1917 * the module ref count.
1918 */
1919 file_ops = find_ftrace_file_ops(file_ops, call->mod);
1920 if (!file_ops)
1921 continue; /* Warn? */
1922 ret = __trace_add_new_mod_event(call, tr, file_ops);
1923 if (ret < 0)
1924 pr_warning("Could not create directory for event %s\n",
1925 call->name);
1926 continue;
1927 }
1928 ret = __trace_add_new_event(call, tr,
1929 &ftrace_event_id_fops,
1930 &ftrace_enable_fops,
1931 &ftrace_event_filter_fops,
1932 &ftrace_event_format_fops);
1933 if (ret < 0)
1934 pr_warning("Could not create directory for event %s\n",
1935 call->name);
1936 }
1937 }
1938
1939 #ifdef CONFIG_DYNAMIC_FTRACE
1940
1941 /* Avoid typos */
1942 #define ENABLE_EVENT_STR "enable_event"
1943 #define DISABLE_EVENT_STR "disable_event"
1944
1945 struct event_probe_data {
1946 struct ftrace_event_file *file;
1947 unsigned long count;
1948 int ref;
1949 bool enable;
1950 };
1951
1952 static struct ftrace_event_file *
1953 find_event_file(struct trace_array *tr, const char *system, const char *event)
1954 {
1955 struct ftrace_event_file *file;
1956 struct ftrace_event_call *call;
1957
1958 list_for_each_entry(file, &tr->events, list) {
1959
1960 call = file->event_call;
1961
1962 if (!call->name || !call->class || !call->class->reg)
1963 continue;
1964
1965 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1966 continue;
1967
1968 if (strcmp(event, call->name) == 0 &&
1969 strcmp(system, call->class->system) == 0)
1970 return file;
1971 }
1972 return NULL;
1973 }
1974
1975 static void
1976 event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1977 {
1978 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1979 struct event_probe_data *data = *pdata;
1980
1981 if (!data)
1982 return;
1983
1984 if (data->enable)
1985 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1986 else
1987 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1988 }
1989
1990 static void
1991 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1992 {
1993 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1994 struct event_probe_data *data = *pdata;
1995
1996 if (!data)
1997 return;
1998
1999 if (!data->count)
2000 return;
2001
2002 /* Skip if the event is in a state we want to switch to */
2003 if (data->enable == !(data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
2004 return;
2005
2006 if (data->count != -1)
2007 (data->count)--;
2008
2009 event_enable_probe(ip, parent_ip, _data);
2010 }
2011
2012 static int
2013 event_enable_print(struct seq_file *m, unsigned long ip,
2014 struct ftrace_probe_ops *ops, void *_data)
2015 {
2016 struct event_probe_data *data = _data;
2017
2018 seq_printf(m, "%ps:", (void *)ip);
2019
2020 seq_printf(m, "%s:%s:%s",
2021 data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
2022 data->file->event_call->class->system,
2023 data->file->event_call->name);
2024
2025 if (data->count == -1)
2026 seq_printf(m, ":unlimited\n");
2027 else
2028 seq_printf(m, ":count=%ld\n", data->count);
2029
2030 return 0;
2031 }
2032
2033 static int
2034 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
2035 void **_data)
2036 {
2037 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2038 struct event_probe_data *data = *pdata;
2039
2040 data->ref++;
2041 return 0;
2042 }
2043
2044 static void
2045 event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
2046 void **_data)
2047 {
2048 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2049 struct event_probe_data *data = *pdata;
2050
2051 if (WARN_ON_ONCE(data->ref <= 0))
2052 return;
2053
2054 data->ref--;
2055 if (!data->ref) {
2056 /* Remove the SOFT_MODE flag */
2057 __ftrace_event_enable_disable(data->file, 0, 1);
2058 module_put(data->file->event_call->mod);
2059 kfree(data);
2060 }
2061 *pdata = NULL;
2062 }
2063
2064 static struct ftrace_probe_ops event_enable_probe_ops = {
2065 .func = event_enable_probe,
2066 .print = event_enable_print,
2067 .init = event_enable_init,
2068 .free = event_enable_free,
2069 };
2070
2071 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2072 .func = event_enable_count_probe,
2073 .print = event_enable_print,
2074 .init = event_enable_init,
2075 .free = event_enable_free,
2076 };
2077
2078 static struct ftrace_probe_ops event_disable_probe_ops = {
2079 .func = event_enable_probe,
2080 .print = event_enable_print,
2081 .init = event_enable_init,
2082 .free = event_enable_free,
2083 };
2084
2085 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2086 .func = event_enable_count_probe,
2087 .print = event_enable_print,
2088 .init = event_enable_init,
2089 .free = event_enable_free,
2090 };
2091
2092 static int
2093 event_enable_func(struct ftrace_hash *hash,
2094 char *glob, char *cmd, char *param, int enabled)
2095 {
2096 struct trace_array *tr = top_trace_array();
2097 struct ftrace_event_file *file;
2098 struct ftrace_probe_ops *ops;
2099 struct event_probe_data *data;
2100 const char *system;
2101 const char *event;
2102 char *number;
2103 bool enable;
2104 int ret;
2105
2106 /* hash funcs only work with set_ftrace_filter */
2107 if (!enabled || !param)
2108 return -EINVAL;
2109
2110 system = strsep(&param, ":");
2111 if (!param)
2112 return -EINVAL;
2113
2114 event = strsep(&param, ":");
2115
2116 mutex_lock(&event_mutex);
2117
2118 ret = -EINVAL;
2119 file = find_event_file(tr, system, event);
2120 if (!file)
2121 goto out;
2122
2123 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2124
2125 if (enable)
2126 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2127 else
2128 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2129
2130 if (glob[0] == '!') {
2131 unregister_ftrace_function_probe_func(glob+1, ops);
2132 ret = 0;
2133 goto out;
2134 }
2135
2136 ret = -ENOMEM;
2137 data = kzalloc(sizeof(*data), GFP_KERNEL);
2138 if (!data)
2139 goto out;
2140
2141 data->enable = enable;
2142 data->count = -1;
2143 data->file = file;
2144
2145 if (!param)
2146 goto out_reg;
2147
2148 number = strsep(&param, ":");
2149
2150 ret = -EINVAL;
2151 if (!strlen(number))
2152 goto out_free;
2153
2154 /*
2155 * We use the callback data field (which is a pointer)
2156 * as our counter.
2157 */
2158 ret = kstrtoul(number, 0, &data->count);
2159 if (ret)
2160 goto out_free;
2161
2162 out_reg:
2163 /* Don't let event modules unload while probe registered */
2164 ret = try_module_get(file->event_call->mod);
2165 if (!ret) {
2166 ret = -EBUSY;
2167 goto out_free;
2168 }
2169
2170 ret = __ftrace_event_enable_disable(file, 1, 1);
2171 if (ret < 0)
2172 goto out_put;
2173 ret = register_ftrace_function_probe(glob, ops, data);
2174 /*
2175 * The above returns on success the # of functions enabled,
2176 * but if it didn't find any functions it returns zero.
2177 * Consider no functions a failure too.
2178 */
2179 if (!ret) {
2180 ret = -ENOENT;
2181 goto out_disable;
2182 } else if (ret < 0)
2183 goto out_disable;
2184 /* Just return zero, not the number of enabled functions */
2185 ret = 0;
2186 out:
2187 mutex_unlock(&event_mutex);
2188 return ret;
2189
2190 out_disable:
2191 __ftrace_event_enable_disable(file, 0, 1);
2192 out_put:
2193 module_put(file->event_call->mod);
2194 out_free:
2195 kfree(data);
2196 goto out;
2197 }
2198
2199 static struct ftrace_func_command event_enable_cmd = {
2200 .name = ENABLE_EVENT_STR,
2201 .func = event_enable_func,
2202 };
2203
2204 static struct ftrace_func_command event_disable_cmd = {
2205 .name = DISABLE_EVENT_STR,
2206 .func = event_enable_func,
2207 };
2208
2209 static __init int register_event_cmds(void)
2210 {
2211 int ret;
2212
2213 ret = register_ftrace_command(&event_enable_cmd);
2214 if (WARN_ON(ret < 0))
2215 return ret;
2216 ret = register_ftrace_command(&event_disable_cmd);
2217 if (WARN_ON(ret < 0))
2218 unregister_ftrace_command(&event_enable_cmd);
2219 return ret;
2220 }
2221 #else
2222 static inline int register_event_cmds(void) { return 0; }
2223 #endif /* CONFIG_DYNAMIC_FTRACE */
2224
2225 /*
2226 * The top level array has already had its ftrace_event_file
2227 * descriptors created in order to allow for early events to
2228 * be recorded. This function is called after the debugfs has been
2229 * initialized, and we now have to create the files associated
2230 * to the events.
2231 */
2232 static __init void
2233 __trace_early_add_event_dirs(struct trace_array *tr)
2234 {
2235 struct ftrace_event_file *file;
2236 int ret;
2237
2238
2239 list_for_each_entry(file, &tr->events, list) {
2240 ret = event_create_dir(tr->event_dir, file,
2241 &ftrace_event_id_fops,
2242 &ftrace_enable_fops,
2243 &ftrace_event_filter_fops,
2244 &ftrace_event_format_fops);
2245 if (ret < 0)
2246 pr_warning("Could not create directory for event %s\n",
2247 file->event_call->name);
2248 }
2249 }
2250
2251 /*
2252 * For early boot up, the top trace array requires to have
2253 * a list of events that can be enabled. This must be done before
2254 * the filesystem is set up in order to allow events to be traced
2255 * early.
2256 */
2257 static __init void
2258 __trace_early_add_events(struct trace_array *tr)
2259 {
2260 struct ftrace_event_call *call;
2261 int ret;
2262
2263 list_for_each_entry(call, &ftrace_events, list) {
2264 /* Early boot up should not have any modules loaded */
2265 if (WARN_ON_ONCE(call->mod))
2266 continue;
2267
2268 ret = __trace_early_add_new_event(call, tr);
2269 if (ret < 0)
2270 pr_warning("Could not create early event %s\n",
2271 call->name);
2272 }
2273 }
2274
2275 /* Remove the event directory structure for a trace directory. */
2276 static void
2277 __trace_remove_event_dirs(struct trace_array *tr)
2278 {
2279 struct ftrace_event_file *file, *next;
2280
2281 list_for_each_entry_safe(file, next, &tr->events, list) {
2282 list_del(&file->list);
2283 debugfs_remove_recursive(file->dir);
2284 remove_subsystem(file->system);
2285 kmem_cache_free(file_cachep, file);
2286 }
2287 }
2288
2289 static void
2290 __add_event_to_tracers(struct ftrace_event_call *call,
2291 struct ftrace_module_file_ops *file_ops)
2292 {
2293 struct trace_array *tr;
2294
2295 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2296 if (file_ops)
2297 __trace_add_new_mod_event(call, tr, file_ops);
2298 else
2299 __trace_add_new_event(call, tr,
2300 &ftrace_event_id_fops,
2301 &ftrace_enable_fops,
2302 &ftrace_event_filter_fops,
2303 &ftrace_event_format_fops);
2304 }
2305 }
2306
2307 static struct notifier_block trace_module_nb = {
2308 .notifier_call = trace_module_notify,
2309 .priority = 0,
2310 };
2311
2312 extern struct ftrace_event_call *__start_ftrace_events[];
2313 extern struct ftrace_event_call *__stop_ftrace_events[];
2314
2315 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2316
2317 static __init int setup_trace_event(char *str)
2318 {
2319 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2320 ring_buffer_expanded = true;
2321 tracing_selftest_disabled = true;
2322
2323 return 1;
2324 }
2325 __setup("trace_event=", setup_trace_event);
2326
2327 /* Expects to have event_mutex held when called */
2328 static int
2329 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2330 {
2331 struct dentry *d_events;
2332 struct dentry *entry;
2333
2334 entry = debugfs_create_file("set_event", 0644, parent,
2335 tr, &ftrace_set_event_fops);
2336 if (!entry) {
2337 pr_warning("Could not create debugfs 'set_event' entry\n");
2338 return -ENOMEM;
2339 }
2340
2341 d_events = debugfs_create_dir("events", parent);
2342 if (!d_events) {
2343 pr_warning("Could not create debugfs 'events' directory\n");
2344 return -ENOMEM;
2345 }
2346
2347 /* ring buffer internal formats */
2348 trace_create_file("header_page", 0444, d_events,
2349 ring_buffer_print_page_header,
2350 &ftrace_show_header_fops);
2351
2352 trace_create_file("header_event", 0444, d_events,
2353 ring_buffer_print_entry_header,
2354 &ftrace_show_header_fops);
2355
2356 trace_create_file("enable", 0644, d_events,
2357 tr, &ftrace_tr_enable_fops);
2358
2359 tr->event_dir = d_events;
2360
2361 return 0;
2362 }
2363
2364 /**
2365 * event_trace_add_tracer - add a instance of a trace_array to events
2366 * @parent: The parent dentry to place the files/directories for events in
2367 * @tr: The trace array associated with these events
2368 *
2369 * When a new instance is created, it needs to set up its events
2370 * directory, as well as other files associated with events. It also
2371 * creates the event hierachry in the @parent/events directory.
2372 *
2373 * Returns 0 on success.
2374 */
2375 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2376 {
2377 int ret;
2378
2379 mutex_lock(&event_mutex);
2380
2381 ret = create_event_toplevel_files(parent, tr);
2382 if (ret)
2383 goto out_unlock;
2384
2385 down_write(&trace_event_sem);
2386 __trace_add_event_dirs(tr);
2387 up_write(&trace_event_sem);
2388
2389 out_unlock:
2390 mutex_unlock(&event_mutex);
2391
2392 return ret;
2393 }
2394
2395 /*
2396 * The top trace array already had its file descriptors created.
2397 * Now the files themselves need to be created.
2398 */
2399 static __init int
2400 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2401 {
2402 int ret;
2403
2404 mutex_lock(&event_mutex);
2405
2406 ret = create_event_toplevel_files(parent, tr);
2407 if (ret)
2408 goto out_unlock;
2409
2410 down_write(&trace_event_sem);
2411 __trace_early_add_event_dirs(tr);
2412 up_write(&trace_event_sem);
2413
2414 out_unlock:
2415 mutex_unlock(&event_mutex);
2416
2417 return ret;
2418 }
2419
2420 int event_trace_del_tracer(struct trace_array *tr)
2421 {
2422 mutex_lock(&event_mutex);
2423
2424 /* Disable any running events */
2425 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
2426
2427 down_write(&trace_event_sem);
2428 __trace_remove_event_dirs(tr);
2429 debugfs_remove_recursive(tr->event_dir);
2430 up_write(&trace_event_sem);
2431
2432 tr->event_dir = NULL;
2433
2434 mutex_unlock(&event_mutex);
2435
2436 return 0;
2437 }
2438
2439 static __init int event_trace_memsetup(void)
2440 {
2441 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
2442 file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC);
2443 return 0;
2444 }
2445
2446 static __init int event_trace_enable(void)
2447 {
2448 struct trace_array *tr = top_trace_array();
2449 struct ftrace_event_call **iter, *call;
2450 char *buf = bootup_event_buf;
2451 char *token;
2452 int ret;
2453
2454 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
2455
2456 call = *iter;
2457 ret = event_init(call);
2458 if (!ret)
2459 list_add(&call->list, &ftrace_events);
2460 }
2461
2462 /*
2463 * We need the top trace array to have a working set of trace
2464 * points at early init, before the debug files and directories
2465 * are created. Create the file entries now, and attach them
2466 * to the actual file dentries later.
2467 */
2468 __trace_early_add_events(tr);
2469
2470 while (true) {
2471 token = strsep(&buf, ",");
2472
2473 if (!token)
2474 break;
2475 if (!*token)
2476 continue;
2477
2478 ret = ftrace_set_clr_event(tr, token, 1);
2479 if (ret)
2480 pr_warn("Failed to enable trace event: %s\n", token);
2481 }
2482
2483 trace_printk_start_comm();
2484
2485 register_event_cmds();
2486
2487 return 0;
2488 }
2489
2490 static __init int event_trace_init(void)
2491 {
2492 struct trace_array *tr;
2493 struct dentry *d_tracer;
2494 struct dentry *entry;
2495 int ret;
2496
2497 tr = top_trace_array();
2498
2499 d_tracer = tracing_init_dentry();
2500 if (!d_tracer)
2501 return 0;
2502
2503 entry = debugfs_create_file("available_events", 0444, d_tracer,
2504 tr, &ftrace_avail_fops);
2505 if (!entry)
2506 pr_warning("Could not create debugfs "
2507 "'available_events' entry\n");
2508
2509 if (trace_define_common_fields())
2510 pr_warning("tracing: Failed to allocate common fields");
2511
2512 ret = early_event_add_tracer(d_tracer, tr);
2513 if (ret)
2514 return ret;
2515
2516 ret = register_module_notifier(&trace_module_nb);
2517 if (ret)
2518 pr_warning("Failed to register trace events module notifier\n");
2519
2520 return 0;
2521 }
2522 early_initcall(event_trace_memsetup);
2523 core_initcall(event_trace_enable);
2524 fs_initcall(event_trace_init);
2525
2526 #ifdef CONFIG_FTRACE_STARTUP_TEST
2527
2528 static DEFINE_SPINLOCK(test_spinlock);
2529 static DEFINE_SPINLOCK(test_spinlock_irq);
2530 static DEFINE_MUTEX(test_mutex);
2531
2532 static __init void test_work(struct work_struct *dummy)
2533 {
2534 spin_lock(&test_spinlock);
2535 spin_lock_irq(&test_spinlock_irq);
2536 udelay(1);
2537 spin_unlock_irq(&test_spinlock_irq);
2538 spin_unlock(&test_spinlock);
2539
2540 mutex_lock(&test_mutex);
2541 msleep(1);
2542 mutex_unlock(&test_mutex);
2543 }
2544
2545 static __init int event_test_thread(void *unused)
2546 {
2547 void *test_malloc;
2548
2549 test_malloc = kmalloc(1234, GFP_KERNEL);
2550 if (!test_malloc)
2551 pr_info("failed to kmalloc\n");
2552
2553 schedule_on_each_cpu(test_work);
2554
2555 kfree(test_malloc);
2556
2557 set_current_state(TASK_INTERRUPTIBLE);
2558 while (!kthread_should_stop())
2559 schedule();
2560
2561 return 0;
2562 }
2563
2564 /*
2565 * Do various things that may trigger events.
2566 */
2567 static __init void event_test_stuff(void)
2568 {
2569 struct task_struct *test_thread;
2570
2571 test_thread = kthread_run(event_test_thread, NULL, "test-events");
2572 msleep(1);
2573 kthread_stop(test_thread);
2574 }
2575
2576 /*
2577 * For every trace event defined, we will test each trace point separately,
2578 * and then by groups, and finally all trace points.
2579 */
2580 static __init void event_trace_self_tests(void)
2581 {
2582 struct ftrace_subsystem_dir *dir;
2583 struct ftrace_event_file *file;
2584 struct ftrace_event_call *call;
2585 struct event_subsystem *system;
2586 struct trace_array *tr;
2587 int ret;
2588
2589 tr = top_trace_array();
2590
2591 pr_info("Running tests on trace events:\n");
2592
2593 list_for_each_entry(file, &tr->events, list) {
2594
2595 call = file->event_call;
2596
2597 /* Only test those that have a probe */
2598 if (!call->class || !call->class->probe)
2599 continue;
2600
2601 /*
2602 * Testing syscall events here is pretty useless, but
2603 * we still do it if configured. But this is time consuming.
2604 * What we really need is a user thread to perform the
2605 * syscalls as we test.
2606 */
2607 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
2608 if (call->class->system &&
2609 strcmp(call->class->system, "syscalls") == 0)
2610 continue;
2611 #endif
2612
2613 pr_info("Testing event %s: ", call->name);
2614
2615 /*
2616 * If an event is already enabled, someone is using
2617 * it and the self test should not be on.
2618 */
2619 if (file->flags & FTRACE_EVENT_FL_ENABLED) {
2620 pr_warning("Enabled event during self test!\n");
2621 WARN_ON_ONCE(1);
2622 continue;
2623 }
2624
2625 ftrace_event_enable_disable(file, 1);
2626 event_test_stuff();
2627 ftrace_event_enable_disable(file, 0);
2628
2629 pr_cont("OK\n");
2630 }
2631
2632 /* Now test at the sub system level */
2633
2634 pr_info("Running tests on trace event systems:\n");
2635
2636 list_for_each_entry(dir, &tr->systems, list) {
2637
2638 system = dir->subsystem;
2639
2640 /* the ftrace system is special, skip it */
2641 if (strcmp(system->name, "ftrace") == 0)
2642 continue;
2643
2644 pr_info("Testing event system %s: ", system->name);
2645
2646 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
2647 if (WARN_ON_ONCE(ret)) {
2648 pr_warning("error enabling system %s\n",
2649 system->name);
2650 continue;
2651 }
2652
2653 event_test_stuff();
2654
2655 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
2656 if (WARN_ON_ONCE(ret)) {
2657 pr_warning("error disabling system %s\n",
2658 system->name);
2659 continue;
2660 }
2661
2662 pr_cont("OK\n");
2663 }
2664
2665 /* Test with all events enabled */
2666
2667 pr_info("Running tests on all trace events:\n");
2668 pr_info("Testing all events: ");
2669
2670 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
2671 if (WARN_ON_ONCE(ret)) {
2672 pr_warning("error enabling all events\n");
2673 return;
2674 }
2675
2676 event_test_stuff();
2677
2678 /* reset sysname */
2679 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
2680 if (WARN_ON_ONCE(ret)) {
2681 pr_warning("error disabling all events\n");
2682 return;
2683 }
2684
2685 pr_cont("OK\n");
2686 }
2687
2688 #ifdef CONFIG_FUNCTION_TRACER
2689
2690 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
2691
2692 static void
2693 function_test_events_call(unsigned long ip, unsigned long parent_ip,
2694 struct ftrace_ops *op, struct pt_regs *pt_regs)
2695 {
2696 struct ring_buffer_event *event;
2697 struct ring_buffer *buffer;
2698 struct ftrace_entry *entry;
2699 unsigned long flags;
2700 long disabled;
2701 int cpu;
2702 int pc;
2703
2704 pc = preempt_count();
2705 preempt_disable_notrace();
2706 cpu = raw_smp_processor_id();
2707 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
2708
2709 if (disabled != 1)
2710 goto out;
2711
2712 local_save_flags(flags);
2713
2714 event = trace_current_buffer_lock_reserve(&buffer,
2715 TRACE_FN, sizeof(*entry),
2716 flags, pc);
2717 if (!event)
2718 goto out;
2719 entry = ring_buffer_event_data(event);
2720 entry->ip = ip;
2721 entry->parent_ip = parent_ip;
2722
2723 trace_buffer_unlock_commit(buffer, event, flags, pc);
2724
2725 out:
2726 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
2727 preempt_enable_notrace();
2728 }
2729
2730 static struct ftrace_ops trace_ops __initdata =
2731 {
2732 .func = function_test_events_call,
2733 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
2734 };
2735
2736 static __init void event_trace_self_test_with_function(void)
2737 {
2738 int ret;
2739 ret = register_ftrace_function(&trace_ops);
2740 if (WARN_ON(ret < 0)) {
2741 pr_info("Failed to enable function tracer for event tests\n");
2742 return;
2743 }
2744 pr_info("Running tests again, along with the function tracer\n");
2745 event_trace_self_tests();
2746 unregister_ftrace_function(&trace_ops);
2747 }
2748 #else
2749 static __init void event_trace_self_test_with_function(void)
2750 {
2751 }
2752 #endif
2753
2754 static __init int event_trace_self_tests_init(void)
2755 {
2756 if (!tracing_selftest_disabled) {
2757 event_trace_self_tests();
2758 event_trace_self_test_with_function();
2759 }
2760
2761 return 0;
2762 }
2763
2764 late_initcall(event_trace_self_tests_init);
2765
2766 #endif
Linus' kernel tree