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Merge branches 'turbostat' and 'x86_energy_perf_policy' into tools
[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 LIST_HEAD(ftrace_events);
31 LIST_HEAD(ftrace_common_fields);
32
33 struct list_head *
34 trace_get_fields(struct ftrace_event_call *event_call)
35 {
36 if (!event_call->class->get_fields)
37 return &event_call->class->fields;
38 return event_call->class->get_fields(event_call);
39 }
40
41 static int __trace_define_field(struct list_head *head, const char *type,
42 const char *name, int offset, int size,
43 int is_signed, int filter_type)
44 {
45 struct ftrace_event_field *field;
46
47 field = kzalloc(sizeof(*field), GFP_KERNEL);
48 if (!field)
49 goto err;
50
51 field->name = kstrdup(name, GFP_KERNEL);
52 if (!field->name)
53 goto err;
54
55 field->type = kstrdup(type, GFP_KERNEL);
56 if (!field->type)
57 goto err;
58
59 if (filter_type == FILTER_OTHER)
60 field->filter_type = filter_assign_type(type);
61 else
62 field->filter_type = filter_type;
63
64 field->offset = offset;
65 field->size = size;
66 field->is_signed = is_signed;
67
68 list_add(&field->link, head);
69
70 return 0;
71
72 err:
73 if (field)
74 kfree(field->name);
75 kfree(field);
76
77 return -ENOMEM;
78 }
79
80 int trace_define_field(struct ftrace_event_call *call, const char *type,
81 const char *name, int offset, int size, int is_signed,
82 int filter_type)
83 {
84 struct list_head *head;
85
86 if (WARN_ON(!call->class))
87 return 0;
88
89 head = trace_get_fields(call);
90 return __trace_define_field(head, type, name, offset, size,
91 is_signed, filter_type);
92 }
93 EXPORT_SYMBOL_GPL(trace_define_field);
94
95 #define __common_field(type, item) \
96 ret = __trace_define_field(&ftrace_common_fields, #type, \
97 "common_" #item, \
98 offsetof(typeof(ent), item), \
99 sizeof(ent.item), \
100 is_signed_type(type), FILTER_OTHER); \
101 if (ret) \
102 return ret;
103
104 static int trace_define_common_fields(void)
105 {
106 int ret;
107 struct trace_entry ent;
108
109 __common_field(unsigned short, type);
110 __common_field(unsigned char, flags);
111 __common_field(unsigned char, preempt_count);
112 __common_field(int, pid);
113 __common_field(int, lock_depth);
114
115 return ret;
116 }
117
118 void trace_destroy_fields(struct ftrace_event_call *call)
119 {
120 struct ftrace_event_field *field, *next;
121 struct list_head *head;
122
123 head = trace_get_fields(call);
124 list_for_each_entry_safe(field, next, head, link) {
125 list_del(&field->link);
126 kfree(field->type);
127 kfree(field->name);
128 kfree(field);
129 }
130 }
131
132 int trace_event_raw_init(struct ftrace_event_call *call)
133 {
134 int id;
135
136 id = register_ftrace_event(&call->event);
137 if (!id)
138 return -ENODEV;
139
140 return 0;
141 }
142 EXPORT_SYMBOL_GPL(trace_event_raw_init);
143
144 int ftrace_event_reg(struct ftrace_event_call *call, enum trace_reg type)
145 {
146 switch (type) {
147 case TRACE_REG_REGISTER:
148 return tracepoint_probe_register(call->name,
149 call->class->probe,
150 call);
151 case TRACE_REG_UNREGISTER:
152 tracepoint_probe_unregister(call->name,
153 call->class->probe,
154 call);
155 return 0;
156
157 #ifdef CONFIG_PERF_EVENTS
158 case TRACE_REG_PERF_REGISTER:
159 return tracepoint_probe_register(call->name,
160 call->class->perf_probe,
161 call);
162 case TRACE_REG_PERF_UNREGISTER:
163 tracepoint_probe_unregister(call->name,
164 call->class->perf_probe,
165 call);
166 return 0;
167 #endif
168 }
169 return 0;
170 }
171 EXPORT_SYMBOL_GPL(ftrace_event_reg);
172
173 void trace_event_enable_cmd_record(bool enable)
174 {
175 struct ftrace_event_call *call;
176
177 mutex_lock(&event_mutex);
178 list_for_each_entry(call, &ftrace_events, list) {
179 if (!(call->flags & TRACE_EVENT_FL_ENABLED))
180 continue;
181
182 if (enable) {
183 tracing_start_cmdline_record();
184 call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
185 } else {
186 tracing_stop_cmdline_record();
187 call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
188 }
189 }
190 mutex_unlock(&event_mutex);
191 }
192
193 static int ftrace_event_enable_disable(struct ftrace_event_call *call,
194 int enable)
195 {
196 int ret = 0;
197
198 switch (enable) {
199 case 0:
200 if (call->flags & TRACE_EVENT_FL_ENABLED) {
201 call->flags &= ~TRACE_EVENT_FL_ENABLED;
202 if (call->flags & TRACE_EVENT_FL_RECORDED_CMD) {
203 tracing_stop_cmdline_record();
204 call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
205 }
206 call->class->reg(call, TRACE_REG_UNREGISTER);
207 }
208 break;
209 case 1:
210 if (!(call->flags & TRACE_EVENT_FL_ENABLED)) {
211 if (trace_flags & TRACE_ITER_RECORD_CMD) {
212 tracing_start_cmdline_record();
213 call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
214 }
215 ret = call->class->reg(call, TRACE_REG_REGISTER);
216 if (ret) {
217 tracing_stop_cmdline_record();
218 pr_info("event trace: Could not enable event "
219 "%s\n", call->name);
220 break;
221 }
222 call->flags |= TRACE_EVENT_FL_ENABLED;
223 }
224 break;
225 }
226
227 return ret;
228 }
229
230 static void ftrace_clear_events(void)
231 {
232 struct ftrace_event_call *call;
233
234 mutex_lock(&event_mutex);
235 list_for_each_entry(call, &ftrace_events, list) {
236 ftrace_event_enable_disable(call, 0);
237 }
238 mutex_unlock(&event_mutex);
239 }
240
241 /*
242 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
243 */
244 static int __ftrace_set_clr_event(const char *match, const char *sub,
245 const char *event, int set)
246 {
247 struct ftrace_event_call *call;
248 int ret = -EINVAL;
249
250 mutex_lock(&event_mutex);
251 list_for_each_entry(call, &ftrace_events, list) {
252
253 if (!call->name || !call->class || !call->class->reg)
254 continue;
255
256 if (match &&
257 strcmp(match, call->name) != 0 &&
258 strcmp(match, call->class->system) != 0)
259 continue;
260
261 if (sub && strcmp(sub, call->class->system) != 0)
262 continue;
263
264 if (event && strcmp(event, call->name) != 0)
265 continue;
266
267 ftrace_event_enable_disable(call, set);
268
269 ret = 0;
270 }
271 mutex_unlock(&event_mutex);
272
273 return ret;
274 }
275
276 static int ftrace_set_clr_event(char *buf, int set)
277 {
278 char *event = NULL, *sub = NULL, *match;
279
280 /*
281 * The buf format can be <subsystem>:<event-name>
282 * *:<event-name> means any event by that name.
283 * :<event-name> is the same.
284 *
285 * <subsystem>:* means all events in that subsystem
286 * <subsystem>: means the same.
287 *
288 * <name> (no ':') means all events in a subsystem with
289 * the name <name> or any event that matches <name>
290 */
291
292 match = strsep(&buf, ":");
293 if (buf) {
294 sub = match;
295 event = buf;
296 match = NULL;
297
298 if (!strlen(sub) || strcmp(sub, "*") == 0)
299 sub = NULL;
300 if (!strlen(event) || strcmp(event, "*") == 0)
301 event = NULL;
302 }
303
304 return __ftrace_set_clr_event(match, sub, event, set);
305 }
306
307 /**
308 * trace_set_clr_event - enable or disable an event
309 * @system: system name to match (NULL for any system)
310 * @event: event name to match (NULL for all events, within system)
311 * @set: 1 to enable, 0 to disable
312 *
313 * This is a way for other parts of the kernel to enable or disable
314 * event recording.
315 *
316 * Returns 0 on success, -EINVAL if the parameters do not match any
317 * registered events.
318 */
319 int trace_set_clr_event(const char *system, const char *event, int set)
320 {
321 return __ftrace_set_clr_event(NULL, system, event, set);
322 }
323
324 /* 128 should be much more than enough */
325 #define EVENT_BUF_SIZE 127
326
327 static ssize_t
328 ftrace_event_write(struct file *file, const char __user *ubuf,
329 size_t cnt, loff_t *ppos)
330 {
331 struct trace_parser parser;
332 ssize_t read, ret;
333
334 if (!cnt)
335 return 0;
336
337 ret = tracing_update_buffers();
338 if (ret < 0)
339 return ret;
340
341 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
342 return -ENOMEM;
343
344 read = trace_get_user(&parser, ubuf, cnt, ppos);
345
346 if (read >= 0 && trace_parser_loaded((&parser))) {
347 int set = 1;
348
349 if (*parser.buffer == '!')
350 set = 0;
351
352 parser.buffer[parser.idx] = 0;
353
354 ret = ftrace_set_clr_event(parser.buffer + !set, set);
355 if (ret)
356 goto out_put;
357 }
358
359 ret = read;
360
361 out_put:
362 trace_parser_put(&parser);
363
364 return ret;
365 }
366
367 static void *
368 t_next(struct seq_file *m, void *v, loff_t *pos)
369 {
370 struct ftrace_event_call *call = v;
371
372 (*pos)++;
373
374 list_for_each_entry_continue(call, &ftrace_events, list) {
375 /*
376 * The ftrace subsystem is for showing formats only.
377 * They can not be enabled or disabled via the event files.
378 */
379 if (call->class && call->class->reg)
380 return call;
381 }
382
383 return NULL;
384 }
385
386 static void *t_start(struct seq_file *m, loff_t *pos)
387 {
388 struct ftrace_event_call *call;
389 loff_t l;
390
391 mutex_lock(&event_mutex);
392
393 call = list_entry(&ftrace_events, struct ftrace_event_call, list);
394 for (l = 0; l <= *pos; ) {
395 call = t_next(m, call, &l);
396 if (!call)
397 break;
398 }
399 return call;
400 }
401
402 static void *
403 s_next(struct seq_file *m, void *v, loff_t *pos)
404 {
405 struct ftrace_event_call *call = v;
406
407 (*pos)++;
408
409 list_for_each_entry_continue(call, &ftrace_events, list) {
410 if (call->flags & TRACE_EVENT_FL_ENABLED)
411 return call;
412 }
413
414 return NULL;
415 }
416
417 static void *s_start(struct seq_file *m, loff_t *pos)
418 {
419 struct ftrace_event_call *call;
420 loff_t l;
421
422 mutex_lock(&event_mutex);
423
424 call = list_entry(&ftrace_events, struct ftrace_event_call, list);
425 for (l = 0; l <= *pos; ) {
426 call = s_next(m, call, &l);
427 if (!call)
428 break;
429 }
430 return call;
431 }
432
433 static int t_show(struct seq_file *m, void *v)
434 {
435 struct ftrace_event_call *call = v;
436
437 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
438 seq_printf(m, "%s:", call->class->system);
439 seq_printf(m, "%s\n", call->name);
440
441 return 0;
442 }
443
444 static void t_stop(struct seq_file *m, void *p)
445 {
446 mutex_unlock(&event_mutex);
447 }
448
449 static int
450 ftrace_event_seq_open(struct inode *inode, struct file *file)
451 {
452 const struct seq_operations *seq_ops;
453
454 if ((file->f_mode & FMODE_WRITE) &&
455 (file->f_flags & O_TRUNC))
456 ftrace_clear_events();
457
458 seq_ops = inode->i_private;
459 return seq_open(file, seq_ops);
460 }
461
462 static ssize_t
463 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
464 loff_t *ppos)
465 {
466 struct ftrace_event_call *call = filp->private_data;
467 char *buf;
468
469 if (call->flags & TRACE_EVENT_FL_ENABLED)
470 buf = "1\n";
471 else
472 buf = "0\n";
473
474 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
475 }
476
477 static ssize_t
478 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
479 loff_t *ppos)
480 {
481 struct ftrace_event_call *call = filp->private_data;
482 char buf[64];
483 unsigned long val;
484 int ret;
485
486 if (cnt >= sizeof(buf))
487 return -EINVAL;
488
489 if (copy_from_user(&buf, ubuf, cnt))
490 return -EFAULT;
491
492 buf[cnt] = 0;
493
494 ret = strict_strtoul(buf, 10, &val);
495 if (ret < 0)
496 return ret;
497
498 ret = tracing_update_buffers();
499 if (ret < 0)
500 return ret;
501
502 switch (val) {
503 case 0:
504 case 1:
505 mutex_lock(&event_mutex);
506 ret = ftrace_event_enable_disable(call, val);
507 mutex_unlock(&event_mutex);
508 break;
509
510 default:
511 return -EINVAL;
512 }
513
514 *ppos += cnt;
515
516 return ret ? ret : cnt;
517 }
518
519 static ssize_t
520 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
521 loff_t *ppos)
522 {
523 const char set_to_char[4] = { '?', '0', '1', 'X' };
524 const char *system = filp->private_data;
525 struct ftrace_event_call *call;
526 char buf[2];
527 int set = 0;
528 int ret;
529
530 mutex_lock(&event_mutex);
531 list_for_each_entry(call, &ftrace_events, list) {
532 if (!call->name || !call->class || !call->class->reg)
533 continue;
534
535 if (system && strcmp(call->class->system, system) != 0)
536 continue;
537
538 /*
539 * We need to find out if all the events are set
540 * or if all events or cleared, or if we have
541 * a mixture.
542 */
543 set |= (1 << !!(call->flags & TRACE_EVENT_FL_ENABLED));
544
545 /*
546 * If we have a mixture, no need to look further.
547 */
548 if (set == 3)
549 break;
550 }
551 mutex_unlock(&event_mutex);
552
553 buf[0] = set_to_char[set];
554 buf[1] = '\n';
555
556 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
557
558 return ret;
559 }
560
561 static ssize_t
562 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
563 loff_t *ppos)
564 {
565 const char *system = filp->private_data;
566 unsigned long val;
567 char buf[64];
568 ssize_t ret;
569
570 if (cnt >= sizeof(buf))
571 return -EINVAL;
572
573 if (copy_from_user(&buf, ubuf, cnt))
574 return -EFAULT;
575
576 buf[cnt] = 0;
577
578 ret = strict_strtoul(buf, 10, &val);
579 if (ret < 0)
580 return ret;
581
582 ret = tracing_update_buffers();
583 if (ret < 0)
584 return ret;
585
586 if (val != 0 && val != 1)
587 return -EINVAL;
588
589 ret = __ftrace_set_clr_event(NULL, system, NULL, val);
590 if (ret)
591 goto out;
592
593 ret = cnt;
594
595 out:
596 *ppos += cnt;
597
598 return ret;
599 }
600
601 enum {
602 FORMAT_HEADER = 1,
603 FORMAT_FIELD_SEPERATOR = 2,
604 FORMAT_PRINTFMT = 3,
605 };
606
607 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
608 {
609 struct ftrace_event_call *call = m->private;
610 struct ftrace_event_field *field;
611 struct list_head *common_head = &ftrace_common_fields;
612 struct list_head *head = trace_get_fields(call);
613
614 (*pos)++;
615
616 switch ((unsigned long)v) {
617 case FORMAT_HEADER:
618 if (unlikely(list_empty(common_head)))
619 return NULL;
620
621 field = list_entry(common_head->prev,
622 struct ftrace_event_field, link);
623 return field;
624
625 case FORMAT_FIELD_SEPERATOR:
626 if (unlikely(list_empty(head)))
627 return NULL;
628
629 field = list_entry(head->prev, struct ftrace_event_field, link);
630 return field;
631
632 case FORMAT_PRINTFMT:
633 /* all done */
634 return NULL;
635 }
636
637 field = v;
638 if (field->link.prev == common_head)
639 return (void *)FORMAT_FIELD_SEPERATOR;
640 else if (field->link.prev == head)
641 return (void *)FORMAT_PRINTFMT;
642
643 field = list_entry(field->link.prev, struct ftrace_event_field, link);
644
645 return field;
646 }
647
648 static void *f_start(struct seq_file *m, loff_t *pos)
649 {
650 loff_t l = 0;
651 void *p;
652
653 /* Start by showing the header */
654 if (!*pos)
655 return (void *)FORMAT_HEADER;
656
657 p = (void *)FORMAT_HEADER;
658 do {
659 p = f_next(m, p, &l);
660 } while (p && l < *pos);
661
662 return p;
663 }
664
665 static int f_show(struct seq_file *m, void *v)
666 {
667 struct ftrace_event_call *call = m->private;
668 struct ftrace_event_field *field;
669 const char *array_descriptor;
670
671 switch ((unsigned long)v) {
672 case FORMAT_HEADER:
673 seq_printf(m, "name: %s\n", call->name);
674 seq_printf(m, "ID: %d\n", call->event.type);
675 seq_printf(m, "format:\n");
676 return 0;
677
678 case FORMAT_FIELD_SEPERATOR:
679 seq_putc(m, '\n');
680 return 0;
681
682 case FORMAT_PRINTFMT:
683 seq_printf(m, "\nprint fmt: %s\n",
684 call->print_fmt);
685 return 0;
686 }
687
688 field = v;
689
690 /*
691 * Smartly shows the array type(except dynamic array).
692 * Normal:
693 * field:TYPE VAR
694 * If TYPE := TYPE[LEN], it is shown:
695 * field:TYPE VAR[LEN]
696 */
697 array_descriptor = strchr(field->type, '[');
698
699 if (!strncmp(field->type, "__data_loc", 10))
700 array_descriptor = NULL;
701
702 if (!array_descriptor)
703 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
704 field->type, field->name, field->offset,
705 field->size, !!field->is_signed);
706 else
707 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
708 (int)(array_descriptor - field->type),
709 field->type, field->name,
710 array_descriptor, field->offset,
711 field->size, !!field->is_signed);
712
713 return 0;
714 }
715
716 static void f_stop(struct seq_file *m, void *p)
717 {
718 }
719
720 static const struct seq_operations trace_format_seq_ops = {
721 .start = f_start,
722 .next = f_next,
723 .stop = f_stop,
724 .show = f_show,
725 };
726
727 static int trace_format_open(struct inode *inode, struct file *file)
728 {
729 struct ftrace_event_call *call = inode->i_private;
730 struct seq_file *m;
731 int ret;
732
733 ret = seq_open(file, &trace_format_seq_ops);
734 if (ret < 0)
735 return ret;
736
737 m = file->private_data;
738 m->private = call;
739
740 return 0;
741 }
742
743 static ssize_t
744 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
745 {
746 struct ftrace_event_call *call = filp->private_data;
747 struct trace_seq *s;
748 int r;
749
750 if (*ppos)
751 return 0;
752
753 s = kmalloc(sizeof(*s), GFP_KERNEL);
754 if (!s)
755 return -ENOMEM;
756
757 trace_seq_init(s);
758 trace_seq_printf(s, "%d\n", call->event.type);
759
760 r = simple_read_from_buffer(ubuf, cnt, ppos,
761 s->buffer, s->len);
762 kfree(s);
763 return r;
764 }
765
766 static ssize_t
767 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
768 loff_t *ppos)
769 {
770 struct ftrace_event_call *call = filp->private_data;
771 struct trace_seq *s;
772 int r;
773
774 if (*ppos)
775 return 0;
776
777 s = kmalloc(sizeof(*s), GFP_KERNEL);
778 if (!s)
779 return -ENOMEM;
780
781 trace_seq_init(s);
782
783 print_event_filter(call, s);
784 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
785
786 kfree(s);
787
788 return r;
789 }
790
791 static ssize_t
792 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
793 loff_t *ppos)
794 {
795 struct ftrace_event_call *call = filp->private_data;
796 char *buf;
797 int err;
798
799 if (cnt >= PAGE_SIZE)
800 return -EINVAL;
801
802 buf = (char *)__get_free_page(GFP_TEMPORARY);
803 if (!buf)
804 return -ENOMEM;
805
806 if (copy_from_user(buf, ubuf, cnt)) {
807 free_page((unsigned long) buf);
808 return -EFAULT;
809 }
810 buf[cnt] = '\0';
811
812 err = apply_event_filter(call, buf);
813 free_page((unsigned long) buf);
814 if (err < 0)
815 return err;
816
817 *ppos += cnt;
818
819 return cnt;
820 }
821
822 static ssize_t
823 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
824 loff_t *ppos)
825 {
826 struct event_subsystem *system = filp->private_data;
827 struct trace_seq *s;
828 int r;
829
830 if (*ppos)
831 return 0;
832
833 s = kmalloc(sizeof(*s), GFP_KERNEL);
834 if (!s)
835 return -ENOMEM;
836
837 trace_seq_init(s);
838
839 print_subsystem_event_filter(system, s);
840 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
841
842 kfree(s);
843
844 return r;
845 }
846
847 static ssize_t
848 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
849 loff_t *ppos)
850 {
851 struct event_subsystem *system = filp->private_data;
852 char *buf;
853 int err;
854
855 if (cnt >= PAGE_SIZE)
856 return -EINVAL;
857
858 buf = (char *)__get_free_page(GFP_TEMPORARY);
859 if (!buf)
860 return -ENOMEM;
861
862 if (copy_from_user(buf, ubuf, cnt)) {
863 free_page((unsigned long) buf);
864 return -EFAULT;
865 }
866 buf[cnt] = '\0';
867
868 err = apply_subsystem_event_filter(system, buf);
869 free_page((unsigned long) buf);
870 if (err < 0)
871 return err;
872
873 *ppos += cnt;
874
875 return cnt;
876 }
877
878 static ssize_t
879 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
880 {
881 int (*func)(struct trace_seq *s) = filp->private_data;
882 struct trace_seq *s;
883 int r;
884
885 if (*ppos)
886 return 0;
887
888 s = kmalloc(sizeof(*s), GFP_KERNEL);
889 if (!s)
890 return -ENOMEM;
891
892 trace_seq_init(s);
893
894 func(s);
895 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
896
897 kfree(s);
898
899 return r;
900 }
901
902 static const struct seq_operations show_event_seq_ops = {
903 .start = t_start,
904 .next = t_next,
905 .show = t_show,
906 .stop = t_stop,
907 };
908
909 static const struct seq_operations show_set_event_seq_ops = {
910 .start = s_start,
911 .next = s_next,
912 .show = t_show,
913 .stop = t_stop,
914 };
915
916 static const struct file_operations ftrace_avail_fops = {
917 .open = ftrace_event_seq_open,
918 .read = seq_read,
919 .llseek = seq_lseek,
920 .release = seq_release,
921 };
922
923 static const struct file_operations ftrace_set_event_fops = {
924 .open = ftrace_event_seq_open,
925 .read = seq_read,
926 .write = ftrace_event_write,
927 .llseek = seq_lseek,
928 .release = seq_release,
929 };
930
931 static const struct file_operations ftrace_enable_fops = {
932 .open = tracing_open_generic,
933 .read = event_enable_read,
934 .write = event_enable_write,
935 .llseek = default_llseek,
936 };
937
938 static const struct file_operations ftrace_event_format_fops = {
939 .open = trace_format_open,
940 .read = seq_read,
941 .llseek = seq_lseek,
942 .release = seq_release,
943 };
944
945 static const struct file_operations ftrace_event_id_fops = {
946 .open = tracing_open_generic,
947 .read = event_id_read,
948 .llseek = default_llseek,
949 };
950
951 static const struct file_operations ftrace_event_filter_fops = {
952 .open = tracing_open_generic,
953 .read = event_filter_read,
954 .write = event_filter_write,
955 .llseek = default_llseek,
956 };
957
958 static const struct file_operations ftrace_subsystem_filter_fops = {
959 .open = tracing_open_generic,
960 .read = subsystem_filter_read,
961 .write = subsystem_filter_write,
962 .llseek = default_llseek,
963 };
964
965 static const struct file_operations ftrace_system_enable_fops = {
966 .open = tracing_open_generic,
967 .read = system_enable_read,
968 .write = system_enable_write,
969 .llseek = default_llseek,
970 };
971
972 static const struct file_operations ftrace_show_header_fops = {
973 .open = tracing_open_generic,
974 .read = show_header,
975 .llseek = default_llseek,
976 };
977
978 static struct dentry *event_trace_events_dir(void)
979 {
980 static struct dentry *d_tracer;
981 static struct dentry *d_events;
982
983 if (d_events)
984 return d_events;
985
986 d_tracer = tracing_init_dentry();
987 if (!d_tracer)
988 return NULL;
989
990 d_events = debugfs_create_dir("events", d_tracer);
991 if (!d_events)
992 pr_warning("Could not create debugfs "
993 "'events' directory\n");
994
995 return d_events;
996 }
997
998 static LIST_HEAD(event_subsystems);
999
1000 static struct dentry *
1001 event_subsystem_dir(const char *name, struct dentry *d_events)
1002 {
1003 struct event_subsystem *system;
1004 struct dentry *entry;
1005
1006 /* First see if we did not already create this dir */
1007 list_for_each_entry(system, &event_subsystems, list) {
1008 if (strcmp(system->name, name) == 0) {
1009 system->nr_events++;
1010 return system->entry;
1011 }
1012 }
1013
1014 /* need to create new entry */
1015 system = kmalloc(sizeof(*system), GFP_KERNEL);
1016 if (!system) {
1017 pr_warning("No memory to create event subsystem %s\n",
1018 name);
1019 return d_events;
1020 }
1021
1022 system->entry = debugfs_create_dir(name, d_events);
1023 if (!system->entry) {
1024 pr_warning("Could not create event subsystem %s\n",
1025 name);
1026 kfree(system);
1027 return d_events;
1028 }
1029
1030 system->nr_events = 1;
1031 system->name = kstrdup(name, GFP_KERNEL);
1032 if (!system->name) {
1033 debugfs_remove(system->entry);
1034 kfree(system);
1035 return d_events;
1036 }
1037
1038 list_add(&system->list, &event_subsystems);
1039
1040 system->filter = NULL;
1041
1042 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1043 if (!system->filter) {
1044 pr_warning("Could not allocate filter for subsystem "
1045 "'%s'\n", name);
1046 return system->entry;
1047 }
1048
1049 entry = debugfs_create_file("filter", 0644, system->entry, system,
1050 &ftrace_subsystem_filter_fops);
1051 if (!entry) {
1052 kfree(system->filter);
1053 system->filter = NULL;
1054 pr_warning("Could not create debugfs "
1055 "'%s/filter' entry\n", name);
1056 }
1057
1058 trace_create_file("enable", 0644, system->entry,
1059 (void *)system->name,
1060 &ftrace_system_enable_fops);
1061
1062 return system->entry;
1063 }
1064
1065 static int
1066 event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
1067 const struct file_operations *id,
1068 const struct file_operations *enable,
1069 const struct file_operations *filter,
1070 const struct file_operations *format)
1071 {
1072 struct list_head *head;
1073 int ret;
1074
1075 /*
1076 * If the trace point header did not define TRACE_SYSTEM
1077 * then the system would be called "TRACE_SYSTEM".
1078 */
1079 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1080 d_events = event_subsystem_dir(call->class->system, d_events);
1081
1082 call->dir = debugfs_create_dir(call->name, d_events);
1083 if (!call->dir) {
1084 pr_warning("Could not create debugfs "
1085 "'%s' directory\n", call->name);
1086 return -1;
1087 }
1088
1089 if (call->class->reg)
1090 trace_create_file("enable", 0644, call->dir, call,
1091 enable);
1092
1093 #ifdef CONFIG_PERF_EVENTS
1094 if (call->event.type && call->class->reg)
1095 trace_create_file("id", 0444, call->dir, call,
1096 id);
1097 #endif
1098
1099 /*
1100 * Other events may have the same class. Only update
1101 * the fields if they are not already defined.
1102 */
1103 head = trace_get_fields(call);
1104 if (list_empty(head)) {
1105 ret = call->class->define_fields(call);
1106 if (ret < 0) {
1107 pr_warning("Could not initialize trace point"
1108 " events/%s\n", call->name);
1109 return ret;
1110 }
1111 }
1112 trace_create_file("filter", 0644, call->dir, call,
1113 filter);
1114
1115 trace_create_file("format", 0444, call->dir, call,
1116 format);
1117
1118 return 0;
1119 }
1120
1121 static int
1122 __trace_add_event_call(struct ftrace_event_call *call, struct module *mod,
1123 const struct file_operations *id,
1124 const struct file_operations *enable,
1125 const struct file_operations *filter,
1126 const struct file_operations *format)
1127 {
1128 struct dentry *d_events;
1129 int ret;
1130
1131 /* The linker may leave blanks */
1132 if (!call->name)
1133 return -EINVAL;
1134
1135 if (call->class->raw_init) {
1136 ret = call->class->raw_init(call);
1137 if (ret < 0) {
1138 if (ret != -ENOSYS)
1139 pr_warning("Could not initialize trace events/%s\n",
1140 call->name);
1141 return ret;
1142 }
1143 }
1144
1145 d_events = event_trace_events_dir();
1146 if (!d_events)
1147 return -ENOENT;
1148
1149 ret = event_create_dir(call, d_events, id, enable, filter, format);
1150 if (!ret)
1151 list_add(&call->list, &ftrace_events);
1152 call->mod = mod;
1153
1154 return ret;
1155 }
1156
1157 /* Add an additional event_call dynamically */
1158 int trace_add_event_call(struct ftrace_event_call *call)
1159 {
1160 int ret;
1161 mutex_lock(&event_mutex);
1162 ret = __trace_add_event_call(call, NULL, &ftrace_event_id_fops,
1163 &ftrace_enable_fops,
1164 &ftrace_event_filter_fops,
1165 &ftrace_event_format_fops);
1166 mutex_unlock(&event_mutex);
1167 return ret;
1168 }
1169
1170 static void remove_subsystem_dir(const char *name)
1171 {
1172 struct event_subsystem *system;
1173
1174 if (strcmp(name, TRACE_SYSTEM) == 0)
1175 return;
1176
1177 list_for_each_entry(system, &event_subsystems, list) {
1178 if (strcmp(system->name, name) == 0) {
1179 if (!--system->nr_events) {
1180 struct event_filter *filter = system->filter;
1181
1182 debugfs_remove_recursive(system->entry);
1183 list_del(&system->list);
1184 if (filter) {
1185 kfree(filter->filter_string);
1186 kfree(filter);
1187 }
1188 kfree(system->name);
1189 kfree(system);
1190 }
1191 break;
1192 }
1193 }
1194 }
1195
1196 /*
1197 * Must be called under locking both of event_mutex and trace_event_mutex.
1198 */
1199 static void __trace_remove_event_call(struct ftrace_event_call *call)
1200 {
1201 ftrace_event_enable_disable(call, 0);
1202 if (call->event.funcs)
1203 __unregister_ftrace_event(&call->event);
1204 debugfs_remove_recursive(call->dir);
1205 list_del(&call->list);
1206 trace_destroy_fields(call);
1207 destroy_preds(call);
1208 remove_subsystem_dir(call->class->system);
1209 }
1210
1211 /* Remove an event_call */
1212 void trace_remove_event_call(struct ftrace_event_call *call)
1213 {
1214 mutex_lock(&event_mutex);
1215 down_write(&trace_event_mutex);
1216 __trace_remove_event_call(call);
1217 up_write(&trace_event_mutex);
1218 mutex_unlock(&event_mutex);
1219 }
1220
1221 #define for_each_event(event, start, end) \
1222 for (event = start; \
1223 (unsigned long)event < (unsigned long)end; \
1224 event++)
1225
1226 #ifdef CONFIG_MODULES
1227
1228 static LIST_HEAD(ftrace_module_file_list);
1229
1230 /*
1231 * Modules must own their file_operations to keep up with
1232 * reference counting.
1233 */
1234 struct ftrace_module_file_ops {
1235 struct list_head list;
1236 struct module *mod;
1237 struct file_operations id;
1238 struct file_operations enable;
1239 struct file_operations format;
1240 struct file_operations filter;
1241 };
1242
1243 static struct ftrace_module_file_ops *
1244 trace_create_file_ops(struct module *mod)
1245 {
1246 struct ftrace_module_file_ops *file_ops;
1247
1248 /*
1249 * This is a bit of a PITA. To allow for correct reference
1250 * counting, modules must "own" their file_operations.
1251 * To do this, we allocate the file operations that will be
1252 * used in the event directory.
1253 */
1254
1255 file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1256 if (!file_ops)
1257 return NULL;
1258
1259 file_ops->mod = mod;
1260
1261 file_ops->id = ftrace_event_id_fops;
1262 file_ops->id.owner = mod;
1263
1264 file_ops->enable = ftrace_enable_fops;
1265 file_ops->enable.owner = mod;
1266
1267 file_ops->filter = ftrace_event_filter_fops;
1268 file_ops->filter.owner = mod;
1269
1270 file_ops->format = ftrace_event_format_fops;
1271 file_ops->format.owner = mod;
1272
1273 list_add(&file_ops->list, &ftrace_module_file_list);
1274
1275 return file_ops;
1276 }
1277
1278 static void trace_module_add_events(struct module *mod)
1279 {
1280 struct ftrace_module_file_ops *file_ops = NULL;
1281 struct ftrace_event_call *call, *start, *end;
1282
1283 start = mod->trace_events;
1284 end = mod->trace_events + mod->num_trace_events;
1285
1286 if (start == end)
1287 return;
1288
1289 file_ops = trace_create_file_ops(mod);
1290 if (!file_ops)
1291 return;
1292
1293 for_each_event(call, start, end) {
1294 __trace_add_event_call(call, mod,
1295 &file_ops->id, &file_ops->enable,
1296 &file_ops->filter, &file_ops->format);
1297 }
1298 }
1299
1300 static void trace_module_remove_events(struct module *mod)
1301 {
1302 struct ftrace_module_file_ops *file_ops;
1303 struct ftrace_event_call *call, *p;
1304 bool found = false;
1305
1306 down_write(&trace_event_mutex);
1307 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1308 if (call->mod == mod) {
1309 found = true;
1310 __trace_remove_event_call(call);
1311 }
1312 }
1313
1314 /* Now free the file_operations */
1315 list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1316 if (file_ops->mod == mod)
1317 break;
1318 }
1319 if (&file_ops->list != &ftrace_module_file_list) {
1320 list_del(&file_ops->list);
1321 kfree(file_ops);
1322 }
1323
1324 /*
1325 * It is safest to reset the ring buffer if the module being unloaded
1326 * registered any events.
1327 */
1328 if (found)
1329 tracing_reset_current_online_cpus();
1330 up_write(&trace_event_mutex);
1331 }
1332
1333 static int trace_module_notify(struct notifier_block *self,
1334 unsigned long val, void *data)
1335 {
1336 struct module *mod = data;
1337
1338 mutex_lock(&event_mutex);
1339 switch (val) {
1340 case MODULE_STATE_COMING:
1341 trace_module_add_events(mod);
1342 break;
1343 case MODULE_STATE_GOING:
1344 trace_module_remove_events(mod);
1345 break;
1346 }
1347 mutex_unlock(&event_mutex);
1348
1349 return 0;
1350 }
1351 #else
1352 static int trace_module_notify(struct notifier_block *self,
1353 unsigned long val, void *data)
1354 {
1355 return 0;
1356 }
1357 #endif /* CONFIG_MODULES */
1358
1359 static struct notifier_block trace_module_nb = {
1360 .notifier_call = trace_module_notify,
1361 .priority = 0,
1362 };
1363
1364 extern struct ftrace_event_call __start_ftrace_events[];
1365 extern struct ftrace_event_call __stop_ftrace_events[];
1366
1367 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
1368
1369 static __init int setup_trace_event(char *str)
1370 {
1371 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
1372 ring_buffer_expanded = 1;
1373 tracing_selftest_disabled = 1;
1374
1375 return 1;
1376 }
1377 __setup("trace_event=", setup_trace_event);
1378
1379 static __init int event_trace_init(void)
1380 {
1381 struct ftrace_event_call *call;
1382 struct dentry *d_tracer;
1383 struct dentry *entry;
1384 struct dentry *d_events;
1385 int ret;
1386 char *buf = bootup_event_buf;
1387 char *token;
1388
1389 d_tracer = tracing_init_dentry();
1390 if (!d_tracer)
1391 return 0;
1392
1393 entry = debugfs_create_file("available_events", 0444, d_tracer,
1394 (void *)&show_event_seq_ops,
1395 &ftrace_avail_fops);
1396 if (!entry)
1397 pr_warning("Could not create debugfs "
1398 "'available_events' entry\n");
1399
1400 entry = debugfs_create_file("set_event", 0644, d_tracer,
1401 (void *)&show_set_event_seq_ops,
1402 &ftrace_set_event_fops);
1403 if (!entry)
1404 pr_warning("Could not create debugfs "
1405 "'set_event' entry\n");
1406
1407 d_events = event_trace_events_dir();
1408 if (!d_events)
1409 return 0;
1410
1411 /* ring buffer internal formats */
1412 trace_create_file("header_page", 0444, d_events,
1413 ring_buffer_print_page_header,
1414 &ftrace_show_header_fops);
1415
1416 trace_create_file("header_event", 0444, d_events,
1417 ring_buffer_print_entry_header,
1418 &ftrace_show_header_fops);
1419
1420 trace_create_file("enable", 0644, d_events,
1421 NULL, &ftrace_system_enable_fops);
1422
1423 if (trace_define_common_fields())
1424 pr_warning("tracing: Failed to allocate common fields");
1425
1426 for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
1427 __trace_add_event_call(call, NULL, &ftrace_event_id_fops,
1428 &ftrace_enable_fops,
1429 &ftrace_event_filter_fops,
1430 &ftrace_event_format_fops);
1431 }
1432
1433 while (true) {
1434 token = strsep(&buf, ",");
1435
1436 if (!token)
1437 break;
1438 if (!*token)
1439 continue;
1440
1441 ret = ftrace_set_clr_event(token, 1);
1442 if (ret)
1443 pr_warning("Failed to enable trace event: %s\n", token);
1444 }
1445
1446 ret = register_module_notifier(&trace_module_nb);
1447 if (ret)
1448 pr_warning("Failed to register trace events module notifier\n");
1449
1450 return 0;
1451 }
1452 fs_initcall(event_trace_init);
1453
1454 #ifdef CONFIG_FTRACE_STARTUP_TEST
1455
1456 static DEFINE_SPINLOCK(test_spinlock);
1457 static DEFINE_SPINLOCK(test_spinlock_irq);
1458 static DEFINE_MUTEX(test_mutex);
1459
1460 static __init void test_work(struct work_struct *dummy)
1461 {
1462 spin_lock(&test_spinlock);
1463 spin_lock_irq(&test_spinlock_irq);
1464 udelay(1);
1465 spin_unlock_irq(&test_spinlock_irq);
1466 spin_unlock(&test_spinlock);
1467
1468 mutex_lock(&test_mutex);
1469 msleep(1);
1470 mutex_unlock(&test_mutex);
1471 }
1472
1473 static __init int event_test_thread(void *unused)
1474 {
1475 void *test_malloc;
1476
1477 test_malloc = kmalloc(1234, GFP_KERNEL);
1478 if (!test_malloc)
1479 pr_info("failed to kmalloc\n");
1480
1481 schedule_on_each_cpu(test_work);
1482
1483 kfree(test_malloc);
1484
1485 set_current_state(TASK_INTERRUPTIBLE);
1486 while (!kthread_should_stop())
1487 schedule();
1488
1489 return 0;
1490 }
1491
1492 /*
1493 * Do various things that may trigger events.
1494 */
1495 static __init void event_test_stuff(void)
1496 {
1497 struct task_struct *test_thread;
1498
1499 test_thread = kthread_run(event_test_thread, NULL, "test-events");
1500 msleep(1);
1501 kthread_stop(test_thread);
1502 }
1503
1504 /*
1505 * For every trace event defined, we will test each trace point separately,
1506 * and then by groups, and finally all trace points.
1507 */
1508 static __init void event_trace_self_tests(void)
1509 {
1510 struct ftrace_event_call *call;
1511 struct event_subsystem *system;
1512 int ret;
1513
1514 pr_info("Running tests on trace events:\n");
1515
1516 list_for_each_entry(call, &ftrace_events, list) {
1517
1518 /* Only test those that have a probe */
1519 if (!call->class || !call->class->probe)
1520 continue;
1521
1522 /*
1523 * Testing syscall events here is pretty useless, but
1524 * we still do it if configured. But this is time consuming.
1525 * What we really need is a user thread to perform the
1526 * syscalls as we test.
1527 */
1528 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
1529 if (call->class->system &&
1530 strcmp(call->class->system, "syscalls") == 0)
1531 continue;
1532 #endif
1533
1534 pr_info("Testing event %s: ", call->name);
1535
1536 /*
1537 * If an event is already enabled, someone is using
1538 * it and the self test should not be on.
1539 */
1540 if (call->flags & TRACE_EVENT_FL_ENABLED) {
1541 pr_warning("Enabled event during self test!\n");
1542 WARN_ON_ONCE(1);
1543 continue;
1544 }
1545
1546 ftrace_event_enable_disable(call, 1);
1547 event_test_stuff();
1548 ftrace_event_enable_disable(call, 0);
1549
1550 pr_cont("OK\n");
1551 }
1552
1553 /* Now test at the sub system level */
1554
1555 pr_info("Running tests on trace event systems:\n");
1556
1557 list_for_each_entry(system, &event_subsystems, list) {
1558
1559 /* the ftrace system is special, skip it */
1560 if (strcmp(system->name, "ftrace") == 0)
1561 continue;
1562
1563 pr_info("Testing event system %s: ", system->name);
1564
1565 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
1566 if (WARN_ON_ONCE(ret)) {
1567 pr_warning("error enabling system %s\n",
1568 system->name);
1569 continue;
1570 }
1571
1572 event_test_stuff();
1573
1574 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
1575 if (WARN_ON_ONCE(ret))
1576 pr_warning("error disabling system %s\n",
1577 system->name);
1578
1579 pr_cont("OK\n");
1580 }
1581
1582 /* Test with all events enabled */
1583
1584 pr_info("Running tests on all trace events:\n");
1585 pr_info("Testing all events: ");
1586
1587 ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
1588 if (WARN_ON_ONCE(ret)) {
1589 pr_warning("error enabling all events\n");
1590 return;
1591 }
1592
1593 event_test_stuff();
1594
1595 /* reset sysname */
1596 ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
1597 if (WARN_ON_ONCE(ret)) {
1598 pr_warning("error disabling all events\n");
1599 return;
1600 }
1601
1602 pr_cont("OK\n");
1603 }
1604
1605 #ifdef CONFIG_FUNCTION_TRACER
1606
1607 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
1608
1609 static void
1610 function_test_events_call(unsigned long ip, unsigned long parent_ip)
1611 {
1612 struct ring_buffer_event *event;
1613 struct ring_buffer *buffer;
1614 struct ftrace_entry *entry;
1615 unsigned long flags;
1616 long disabled;
1617 int cpu;
1618 int pc;
1619
1620 pc = preempt_count();
1621 preempt_disable_notrace();
1622 cpu = raw_smp_processor_id();
1623 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
1624
1625 if (disabled != 1)
1626 goto out;
1627
1628 local_save_flags(flags);
1629
1630 event = trace_current_buffer_lock_reserve(&buffer,
1631 TRACE_FN, sizeof(*entry),
1632 flags, pc);
1633 if (!event)
1634 goto out;
1635 entry = ring_buffer_event_data(event);
1636 entry->ip = ip;
1637 entry->parent_ip = parent_ip;
1638
1639 trace_nowake_buffer_unlock_commit(buffer, event, flags, pc);
1640
1641 out:
1642 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
1643 preempt_enable_notrace();
1644 }
1645
1646 static struct ftrace_ops trace_ops __initdata =
1647 {
1648 .func = function_test_events_call,
1649 };
1650
1651 static __init void event_trace_self_test_with_function(void)
1652 {
1653 register_ftrace_function(&trace_ops);
1654 pr_info("Running tests again, along with the function tracer\n");
1655 event_trace_self_tests();
1656 unregister_ftrace_function(&trace_ops);
1657 }
1658 #else
1659 static __init void event_trace_self_test_with_function(void)
1660 {
1661 }
1662 #endif
1663
1664 static __init int event_trace_self_tests_init(void)
1665 {
1666 if (!tracing_selftest_disabled) {
1667 event_trace_self_tests();
1668 event_trace_self_test_with_function();
1669 }
1670
1671 return 0;
1672 }
1673
1674 late_initcall(event_trace_self_tests_init);
1675
1676 #endif
Linux kernel - Deliverables
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