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tracing: Remove per event trace registering
[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
32 int trace_define_field(struct ftrace_event_call *call, const char *type,
33 const char *name, int offset, int size, int is_signed,
34 int filter_type)
35 {
36 struct ftrace_event_field *field;
37
38 field = kzalloc(sizeof(*field), GFP_KERNEL);
39 if (!field)
40 goto err;
41
42 field->name = kstrdup(name, GFP_KERNEL);
43 if (!field->name)
44 goto err;
45
46 field->type = kstrdup(type, GFP_KERNEL);
47 if (!field->type)
48 goto err;
49
50 if (filter_type == FILTER_OTHER)
51 field->filter_type = filter_assign_type(type);
52 else
53 field->filter_type = filter_type;
54
55 field->offset = offset;
56 field->size = size;
57 field->is_signed = is_signed;
58
59 list_add(&field->link, &call->fields);
60
61 return 0;
62
63 err:
64 if (field)
65 kfree(field->name);
66 kfree(field);
67
68 return -ENOMEM;
69 }
70 EXPORT_SYMBOL_GPL(trace_define_field);
71
72 #define __common_field(type, item) \
73 ret = trace_define_field(call, #type, "common_" #item, \
74 offsetof(typeof(ent), item), \
75 sizeof(ent.item), \
76 is_signed_type(type), FILTER_OTHER); \
77 if (ret) \
78 return ret;
79
80 static int trace_define_common_fields(struct ftrace_event_call *call)
81 {
82 int ret;
83 struct trace_entry ent;
84
85 __common_field(unsigned short, type);
86 __common_field(unsigned char, flags);
87 __common_field(unsigned char, preempt_count);
88 __common_field(int, pid);
89 __common_field(int, lock_depth);
90
91 return ret;
92 }
93
94 void trace_destroy_fields(struct ftrace_event_call *call)
95 {
96 struct ftrace_event_field *field, *next;
97
98 list_for_each_entry_safe(field, next, &call->fields, link) {
99 list_del(&field->link);
100 kfree(field->type);
101 kfree(field->name);
102 kfree(field);
103 }
104 }
105
106 int trace_event_raw_init(struct ftrace_event_call *call)
107 {
108 int id;
109
110 id = register_ftrace_event(call->event);
111 if (!id)
112 return -ENODEV;
113 call->id = id;
114 INIT_LIST_HEAD(&call->fields);
115
116 return 0;
117 }
118 EXPORT_SYMBOL_GPL(trace_event_raw_init);
119
120 static int ftrace_event_enable_disable(struct ftrace_event_call *call,
121 int enable)
122 {
123 int ret = 0;
124
125 switch (enable) {
126 case 0:
127 if (call->enabled) {
128 call->enabled = 0;
129 tracing_stop_cmdline_record();
130 if (call->class->reg)
131 call->class->reg(call, TRACE_REG_UNREGISTER);
132 else
133 tracepoint_probe_unregister(call->name,
134 call->class->probe,
135 call);
136 }
137 break;
138 case 1:
139 if (!call->enabled) {
140 tracing_start_cmdline_record();
141 if (call->class->reg)
142 ret = call->class->reg(call, TRACE_REG_REGISTER);
143 else
144 ret = tracepoint_probe_register(call->name,
145 call->class->probe,
146 call);
147 if (ret) {
148 tracing_stop_cmdline_record();
149 pr_info("event trace: Could not enable event "
150 "%s\n", call->name);
151 break;
152 }
153 call->enabled = 1;
154 }
155 break;
156 }
157
158 return ret;
159 }
160
161 static void ftrace_clear_events(void)
162 {
163 struct ftrace_event_call *call;
164
165 mutex_lock(&event_mutex);
166 list_for_each_entry(call, &ftrace_events, list) {
167 ftrace_event_enable_disable(call, 0);
168 }
169 mutex_unlock(&event_mutex);
170 }
171
172 /*
173 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
174 */
175 static int __ftrace_set_clr_event(const char *match, const char *sub,
176 const char *event, int set)
177 {
178 struct ftrace_event_call *call;
179 int ret = -EINVAL;
180
181 mutex_lock(&event_mutex);
182 list_for_each_entry(call, &ftrace_events, list) {
183
184 if (!call->name || !call->class ||
185 (!call->class->probe && !call->class->reg))
186 continue;
187
188 if (match &&
189 strcmp(match, call->name) != 0 &&
190 strcmp(match, call->class->system) != 0)
191 continue;
192
193 if (sub && strcmp(sub, call->class->system) != 0)
194 continue;
195
196 if (event && strcmp(event, call->name) != 0)
197 continue;
198
199 ftrace_event_enable_disable(call, set);
200
201 ret = 0;
202 }
203 mutex_unlock(&event_mutex);
204
205 return ret;
206 }
207
208 static int ftrace_set_clr_event(char *buf, int set)
209 {
210 char *event = NULL, *sub = NULL, *match;
211
212 /*
213 * The buf format can be <subsystem>:<event-name>
214 * *:<event-name> means any event by that name.
215 * :<event-name> is the same.
216 *
217 * <subsystem>:* means all events in that subsystem
218 * <subsystem>: means the same.
219 *
220 * <name> (no ':') means all events in a subsystem with
221 * the name <name> or any event that matches <name>
222 */
223
224 match = strsep(&buf, ":");
225 if (buf) {
226 sub = match;
227 event = buf;
228 match = NULL;
229
230 if (!strlen(sub) || strcmp(sub, "*") == 0)
231 sub = NULL;
232 if (!strlen(event) || strcmp(event, "*") == 0)
233 event = NULL;
234 }
235
236 return __ftrace_set_clr_event(match, sub, event, set);
237 }
238
239 /**
240 * trace_set_clr_event - enable or disable an event
241 * @system: system name to match (NULL for any system)
242 * @event: event name to match (NULL for all events, within system)
243 * @set: 1 to enable, 0 to disable
244 *
245 * This is a way for other parts of the kernel to enable or disable
246 * event recording.
247 *
248 * Returns 0 on success, -EINVAL if the parameters do not match any
249 * registered events.
250 */
251 int trace_set_clr_event(const char *system, const char *event, int set)
252 {
253 return __ftrace_set_clr_event(NULL, system, event, set);
254 }
255
256 /* 128 should be much more than enough */
257 #define EVENT_BUF_SIZE 127
258
259 static ssize_t
260 ftrace_event_write(struct file *file, const char __user *ubuf,
261 size_t cnt, loff_t *ppos)
262 {
263 struct trace_parser parser;
264 ssize_t read, ret;
265
266 if (!cnt)
267 return 0;
268
269 ret = tracing_update_buffers();
270 if (ret < 0)
271 return ret;
272
273 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
274 return -ENOMEM;
275
276 read = trace_get_user(&parser, ubuf, cnt, ppos);
277
278 if (read >= 0 && trace_parser_loaded((&parser))) {
279 int set = 1;
280
281 if (*parser.buffer == '!')
282 set = 0;
283
284 parser.buffer[parser.idx] = 0;
285
286 ret = ftrace_set_clr_event(parser.buffer + !set, set);
287 if (ret)
288 goto out_put;
289 }
290
291 ret = read;
292
293 out_put:
294 trace_parser_put(&parser);
295
296 return ret;
297 }
298
299 static void *
300 t_next(struct seq_file *m, void *v, loff_t *pos)
301 {
302 struct ftrace_event_call *call = v;
303
304 (*pos)++;
305
306 list_for_each_entry_continue(call, &ftrace_events, list) {
307 /*
308 * The ftrace subsystem is for showing formats only.
309 * They can not be enabled or disabled via the event files.
310 */
311 if (call->class && (call->class->probe || call->class->reg))
312 return call;
313 }
314
315 return NULL;
316 }
317
318 static void *t_start(struct seq_file *m, loff_t *pos)
319 {
320 struct ftrace_event_call *call;
321 loff_t l;
322
323 mutex_lock(&event_mutex);
324
325 call = list_entry(&ftrace_events, struct ftrace_event_call, list);
326 for (l = 0; l <= *pos; ) {
327 call = t_next(m, call, &l);
328 if (!call)
329 break;
330 }
331 return call;
332 }
333
334 static void *
335 s_next(struct seq_file *m, void *v, loff_t *pos)
336 {
337 struct ftrace_event_call *call = v;
338
339 (*pos)++;
340
341 list_for_each_entry_continue(call, &ftrace_events, list) {
342 if (call->enabled)
343 return call;
344 }
345
346 return NULL;
347 }
348
349 static void *s_start(struct seq_file *m, loff_t *pos)
350 {
351 struct ftrace_event_call *call;
352 loff_t l;
353
354 mutex_lock(&event_mutex);
355
356 call = list_entry(&ftrace_events, struct ftrace_event_call, list);
357 for (l = 0; l <= *pos; ) {
358 call = s_next(m, call, &l);
359 if (!call)
360 break;
361 }
362 return call;
363 }
364
365 static int t_show(struct seq_file *m, void *v)
366 {
367 struct ftrace_event_call *call = v;
368
369 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
370 seq_printf(m, "%s:", call->class->system);
371 seq_printf(m, "%s\n", call->name);
372
373 return 0;
374 }
375
376 static void t_stop(struct seq_file *m, void *p)
377 {
378 mutex_unlock(&event_mutex);
379 }
380
381 static int
382 ftrace_event_seq_open(struct inode *inode, struct file *file)
383 {
384 const struct seq_operations *seq_ops;
385
386 if ((file->f_mode & FMODE_WRITE) &&
387 (file->f_flags & O_TRUNC))
388 ftrace_clear_events();
389
390 seq_ops = inode->i_private;
391 return seq_open(file, seq_ops);
392 }
393
394 static ssize_t
395 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
396 loff_t *ppos)
397 {
398 struct ftrace_event_call *call = filp->private_data;
399 char *buf;
400
401 if (call->enabled)
402 buf = "1\n";
403 else
404 buf = "0\n";
405
406 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
407 }
408
409 static ssize_t
410 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
411 loff_t *ppos)
412 {
413 struct ftrace_event_call *call = filp->private_data;
414 char buf[64];
415 unsigned long val;
416 int ret;
417
418 if (cnt >= sizeof(buf))
419 return -EINVAL;
420
421 if (copy_from_user(&buf, ubuf, cnt))
422 return -EFAULT;
423
424 buf[cnt] = 0;
425
426 ret = strict_strtoul(buf, 10, &val);
427 if (ret < 0)
428 return ret;
429
430 ret = tracing_update_buffers();
431 if (ret < 0)
432 return ret;
433
434 switch (val) {
435 case 0:
436 case 1:
437 mutex_lock(&event_mutex);
438 ret = ftrace_event_enable_disable(call, val);
439 mutex_unlock(&event_mutex);
440 break;
441
442 default:
443 return -EINVAL;
444 }
445
446 *ppos += cnt;
447
448 return ret ? ret : cnt;
449 }
450
451 static ssize_t
452 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
453 loff_t *ppos)
454 {
455 const char set_to_char[4] = { '?', '0', '1', 'X' };
456 const char *system = filp->private_data;
457 struct ftrace_event_call *call;
458 char buf[2];
459 int set = 0;
460 int ret;
461
462 mutex_lock(&event_mutex);
463 list_for_each_entry(call, &ftrace_events, list) {
464 if (!call->name || !call->class ||
465 (!call->class->probe && !call->class->reg))
466 continue;
467
468 if (system && strcmp(call->class->system, system) != 0)
469 continue;
470
471 /*
472 * We need to find out if all the events are set
473 * or if all events or cleared, or if we have
474 * a mixture.
475 */
476 set |= (1 << !!call->enabled);
477
478 /*
479 * If we have a mixture, no need to look further.
480 */
481 if (set == 3)
482 break;
483 }
484 mutex_unlock(&event_mutex);
485
486 buf[0] = set_to_char[set];
487 buf[1] = '\n';
488
489 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
490
491 return ret;
492 }
493
494 static ssize_t
495 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
496 loff_t *ppos)
497 {
498 const char *system = filp->private_data;
499 unsigned long val;
500 char buf[64];
501 ssize_t ret;
502
503 if (cnt >= sizeof(buf))
504 return -EINVAL;
505
506 if (copy_from_user(&buf, ubuf, cnt))
507 return -EFAULT;
508
509 buf[cnt] = 0;
510
511 ret = strict_strtoul(buf, 10, &val);
512 if (ret < 0)
513 return ret;
514
515 ret = tracing_update_buffers();
516 if (ret < 0)
517 return ret;
518
519 if (val != 0 && val != 1)
520 return -EINVAL;
521
522 ret = __ftrace_set_clr_event(NULL, system, NULL, val);
523 if (ret)
524 goto out;
525
526 ret = cnt;
527
528 out:
529 *ppos += cnt;
530
531 return ret;
532 }
533
534 static ssize_t
535 event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
536 loff_t *ppos)
537 {
538 struct ftrace_event_call *call = filp->private_data;
539 struct ftrace_event_field *field;
540 struct trace_seq *s;
541 int common_field_count = 5;
542 char *buf;
543 int r = 0;
544
545 if (*ppos)
546 return 0;
547
548 s = kmalloc(sizeof(*s), GFP_KERNEL);
549 if (!s)
550 return -ENOMEM;
551
552 trace_seq_init(s);
553
554 trace_seq_printf(s, "name: %s\n", call->name);
555 trace_seq_printf(s, "ID: %d\n", call->id);
556 trace_seq_printf(s, "format:\n");
557
558 list_for_each_entry_reverse(field, &call->fields, link) {
559 /*
560 * Smartly shows the array type(except dynamic array).
561 * Normal:
562 * field:TYPE VAR
563 * If TYPE := TYPE[LEN], it is shown:
564 * field:TYPE VAR[LEN]
565 */
566 const char *array_descriptor = strchr(field->type, '[');
567
568 if (!strncmp(field->type, "__data_loc", 10))
569 array_descriptor = NULL;
570
571 if (!array_descriptor) {
572 r = trace_seq_printf(s, "\tfield:%s %s;\toffset:%u;"
573 "\tsize:%u;\tsigned:%d;\n",
574 field->type, field->name, field->offset,
575 field->size, !!field->is_signed);
576 } else {
577 r = trace_seq_printf(s, "\tfield:%.*s %s%s;\toffset:%u;"
578 "\tsize:%u;\tsigned:%d;\n",
579 (int)(array_descriptor - field->type),
580 field->type, field->name,
581 array_descriptor, field->offset,
582 field->size, !!field->is_signed);
583 }
584
585 if (--common_field_count == 0)
586 r = trace_seq_printf(s, "\n");
587
588 if (!r)
589 break;
590 }
591
592 if (r)
593 r = trace_seq_printf(s, "\nprint fmt: %s\n",
594 call->print_fmt);
595
596 if (!r) {
597 /*
598 * ug! The format output is bigger than a PAGE!!
599 */
600 buf = "FORMAT TOO BIG\n";
601 r = simple_read_from_buffer(ubuf, cnt, ppos,
602 buf, strlen(buf));
603 goto out;
604 }
605
606 r = simple_read_from_buffer(ubuf, cnt, ppos,
607 s->buffer, s->len);
608 out:
609 kfree(s);
610 return r;
611 }
612
613 static ssize_t
614 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
615 {
616 struct ftrace_event_call *call = filp->private_data;
617 struct trace_seq *s;
618 int r;
619
620 if (*ppos)
621 return 0;
622
623 s = kmalloc(sizeof(*s), GFP_KERNEL);
624 if (!s)
625 return -ENOMEM;
626
627 trace_seq_init(s);
628 trace_seq_printf(s, "%d\n", call->id);
629
630 r = simple_read_from_buffer(ubuf, cnt, ppos,
631 s->buffer, s->len);
632 kfree(s);
633 return r;
634 }
635
636 static ssize_t
637 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
638 loff_t *ppos)
639 {
640 struct ftrace_event_call *call = filp->private_data;
641 struct trace_seq *s;
642 int r;
643
644 if (*ppos)
645 return 0;
646
647 s = kmalloc(sizeof(*s), GFP_KERNEL);
648 if (!s)
649 return -ENOMEM;
650
651 trace_seq_init(s);
652
653 print_event_filter(call, s);
654 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
655
656 kfree(s);
657
658 return r;
659 }
660
661 static ssize_t
662 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
663 loff_t *ppos)
664 {
665 struct ftrace_event_call *call = filp->private_data;
666 char *buf;
667 int err;
668
669 if (cnt >= PAGE_SIZE)
670 return -EINVAL;
671
672 buf = (char *)__get_free_page(GFP_TEMPORARY);
673 if (!buf)
674 return -ENOMEM;
675
676 if (copy_from_user(buf, ubuf, cnt)) {
677 free_page((unsigned long) buf);
678 return -EFAULT;
679 }
680 buf[cnt] = '\0';
681
682 err = apply_event_filter(call, buf);
683 free_page((unsigned long) buf);
684 if (err < 0)
685 return err;
686
687 *ppos += cnt;
688
689 return cnt;
690 }
691
692 static ssize_t
693 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
694 loff_t *ppos)
695 {
696 struct event_subsystem *system = filp->private_data;
697 struct trace_seq *s;
698 int r;
699
700 if (*ppos)
701 return 0;
702
703 s = kmalloc(sizeof(*s), GFP_KERNEL);
704 if (!s)
705 return -ENOMEM;
706
707 trace_seq_init(s);
708
709 print_subsystem_event_filter(system, s);
710 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
711
712 kfree(s);
713
714 return r;
715 }
716
717 static ssize_t
718 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
719 loff_t *ppos)
720 {
721 struct event_subsystem *system = filp->private_data;
722 char *buf;
723 int err;
724
725 if (cnt >= PAGE_SIZE)
726 return -EINVAL;
727
728 buf = (char *)__get_free_page(GFP_TEMPORARY);
729 if (!buf)
730 return -ENOMEM;
731
732 if (copy_from_user(buf, ubuf, cnt)) {
733 free_page((unsigned long) buf);
734 return -EFAULT;
735 }
736 buf[cnt] = '\0';
737
738 err = apply_subsystem_event_filter(system, buf);
739 free_page((unsigned long) buf);
740 if (err < 0)
741 return err;
742
743 *ppos += cnt;
744
745 return cnt;
746 }
747
748 static ssize_t
749 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
750 {
751 int (*func)(struct trace_seq *s) = filp->private_data;
752 struct trace_seq *s;
753 int r;
754
755 if (*ppos)
756 return 0;
757
758 s = kmalloc(sizeof(*s), GFP_KERNEL);
759 if (!s)
760 return -ENOMEM;
761
762 trace_seq_init(s);
763
764 func(s);
765 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
766
767 kfree(s);
768
769 return r;
770 }
771
772 static const struct seq_operations show_event_seq_ops = {
773 .start = t_start,
774 .next = t_next,
775 .show = t_show,
776 .stop = t_stop,
777 };
778
779 static const struct seq_operations show_set_event_seq_ops = {
780 .start = s_start,
781 .next = s_next,
782 .show = t_show,
783 .stop = t_stop,
784 };
785
786 static const struct file_operations ftrace_avail_fops = {
787 .open = ftrace_event_seq_open,
788 .read = seq_read,
789 .llseek = seq_lseek,
790 .release = seq_release,
791 };
792
793 static const struct file_operations ftrace_set_event_fops = {
794 .open = ftrace_event_seq_open,
795 .read = seq_read,
796 .write = ftrace_event_write,
797 .llseek = seq_lseek,
798 .release = seq_release,
799 };
800
801 static const struct file_operations ftrace_enable_fops = {
802 .open = tracing_open_generic,
803 .read = event_enable_read,
804 .write = event_enable_write,
805 };
806
807 static const struct file_operations ftrace_event_format_fops = {
808 .open = tracing_open_generic,
809 .read = event_format_read,
810 };
811
812 static const struct file_operations ftrace_event_id_fops = {
813 .open = tracing_open_generic,
814 .read = event_id_read,
815 };
816
817 static const struct file_operations ftrace_event_filter_fops = {
818 .open = tracing_open_generic,
819 .read = event_filter_read,
820 .write = event_filter_write,
821 };
822
823 static const struct file_operations ftrace_subsystem_filter_fops = {
824 .open = tracing_open_generic,
825 .read = subsystem_filter_read,
826 .write = subsystem_filter_write,
827 };
828
829 static const struct file_operations ftrace_system_enable_fops = {
830 .open = tracing_open_generic,
831 .read = system_enable_read,
832 .write = system_enable_write,
833 };
834
835 static const struct file_operations ftrace_show_header_fops = {
836 .open = tracing_open_generic,
837 .read = show_header,
838 };
839
840 static struct dentry *event_trace_events_dir(void)
841 {
842 static struct dentry *d_tracer;
843 static struct dentry *d_events;
844
845 if (d_events)
846 return d_events;
847
848 d_tracer = tracing_init_dentry();
849 if (!d_tracer)
850 return NULL;
851
852 d_events = debugfs_create_dir("events", d_tracer);
853 if (!d_events)
854 pr_warning("Could not create debugfs "
855 "'events' directory\n");
856
857 return d_events;
858 }
859
860 static LIST_HEAD(event_subsystems);
861
862 static struct dentry *
863 event_subsystem_dir(const char *name, struct dentry *d_events)
864 {
865 struct event_subsystem *system;
866 struct dentry *entry;
867
868 /* First see if we did not already create this dir */
869 list_for_each_entry(system, &event_subsystems, list) {
870 if (strcmp(system->name, name) == 0) {
871 system->nr_events++;
872 return system->entry;
873 }
874 }
875
876 /* need to create new entry */
877 system = kmalloc(sizeof(*system), GFP_KERNEL);
878 if (!system) {
879 pr_warning("No memory to create event subsystem %s\n",
880 name);
881 return d_events;
882 }
883
884 system->entry = debugfs_create_dir(name, d_events);
885 if (!system->entry) {
886 pr_warning("Could not create event subsystem %s\n",
887 name);
888 kfree(system);
889 return d_events;
890 }
891
892 system->nr_events = 1;
893 system->name = kstrdup(name, GFP_KERNEL);
894 if (!system->name) {
895 debugfs_remove(system->entry);
896 kfree(system);
897 return d_events;
898 }
899
900 list_add(&system->list, &event_subsystems);
901
902 system->filter = NULL;
903
904 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
905 if (!system->filter) {
906 pr_warning("Could not allocate filter for subsystem "
907 "'%s'\n", name);
908 return system->entry;
909 }
910
911 entry = debugfs_create_file("filter", 0644, system->entry, system,
912 &ftrace_subsystem_filter_fops);
913 if (!entry) {
914 kfree(system->filter);
915 system->filter = NULL;
916 pr_warning("Could not create debugfs "
917 "'%s/filter' entry\n", name);
918 }
919
920 trace_create_file("enable", 0644, system->entry,
921 (void *)system->name,
922 &ftrace_system_enable_fops);
923
924 return system->entry;
925 }
926
927 static int
928 event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
929 const struct file_operations *id,
930 const struct file_operations *enable,
931 const struct file_operations *filter,
932 const struct file_operations *format)
933 {
934 int ret;
935
936 /*
937 * If the trace point header did not define TRACE_SYSTEM
938 * then the system would be called "TRACE_SYSTEM".
939 */
940 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
941 d_events = event_subsystem_dir(call->class->system, d_events);
942
943 call->dir = debugfs_create_dir(call->name, d_events);
944 if (!call->dir) {
945 pr_warning("Could not create debugfs "
946 "'%s' directory\n", call->name);
947 return -1;
948 }
949
950 if (call->class->probe || call->class->reg)
951 trace_create_file("enable", 0644, call->dir, call,
952 enable);
953
954 #ifdef CONFIG_PERF_EVENTS
955 if (call->id && (call->class->perf_probe || call->class->reg))
956 trace_create_file("id", 0444, call->dir, call,
957 id);
958 #endif
959
960 if (call->define_fields) {
961 ret = trace_define_common_fields(call);
962 if (!ret)
963 ret = call->define_fields(call);
964 if (ret < 0) {
965 pr_warning("Could not initialize trace point"
966 " events/%s\n", call->name);
967 return ret;
968 }
969 trace_create_file("filter", 0644, call->dir, call,
970 filter);
971 }
972
973 trace_create_file("format", 0444, call->dir, call,
974 format);
975
976 return 0;
977 }
978
979 static int __trace_add_event_call(struct ftrace_event_call *call)
980 {
981 struct dentry *d_events;
982 int ret;
983
984 if (!call->name)
985 return -EINVAL;
986
987 if (call->raw_init) {
988 ret = call->raw_init(call);
989 if (ret < 0) {
990 if (ret != -ENOSYS)
991 pr_warning("Could not initialize trace "
992 "events/%s\n", call->name);
993 return ret;
994 }
995 }
996
997 d_events = event_trace_events_dir();
998 if (!d_events)
999 return -ENOENT;
1000
1001 ret = event_create_dir(call, d_events, &ftrace_event_id_fops,
1002 &ftrace_enable_fops, &ftrace_event_filter_fops,
1003 &ftrace_event_format_fops);
1004 if (!ret)
1005 list_add(&call->list, &ftrace_events);
1006
1007 return ret;
1008 }
1009
1010 /* Add an additional event_call dynamically */
1011 int trace_add_event_call(struct ftrace_event_call *call)
1012 {
1013 int ret;
1014 mutex_lock(&event_mutex);
1015 ret = __trace_add_event_call(call);
1016 mutex_unlock(&event_mutex);
1017 return ret;
1018 }
1019
1020 static void remove_subsystem_dir(const char *name)
1021 {
1022 struct event_subsystem *system;
1023
1024 if (strcmp(name, TRACE_SYSTEM) == 0)
1025 return;
1026
1027 list_for_each_entry(system, &event_subsystems, list) {
1028 if (strcmp(system->name, name) == 0) {
1029 if (!--system->nr_events) {
1030 struct event_filter *filter = system->filter;
1031
1032 debugfs_remove_recursive(system->entry);
1033 list_del(&system->list);
1034 if (filter) {
1035 kfree(filter->filter_string);
1036 kfree(filter);
1037 }
1038 kfree(system->name);
1039 kfree(system);
1040 }
1041 break;
1042 }
1043 }
1044 }
1045
1046 /*
1047 * Must be called under locking both of event_mutex and trace_event_mutex.
1048 */
1049 static void __trace_remove_event_call(struct ftrace_event_call *call)
1050 {
1051 ftrace_event_enable_disable(call, 0);
1052 if (call->event)
1053 __unregister_ftrace_event(call->event);
1054 debugfs_remove_recursive(call->dir);
1055 list_del(&call->list);
1056 trace_destroy_fields(call);
1057 destroy_preds(call);
1058 remove_subsystem_dir(call->class->system);
1059 }
1060
1061 /* Remove an event_call */
1062 void trace_remove_event_call(struct ftrace_event_call *call)
1063 {
1064 mutex_lock(&event_mutex);
1065 down_write(&trace_event_mutex);
1066 __trace_remove_event_call(call);
1067 up_write(&trace_event_mutex);
1068 mutex_unlock(&event_mutex);
1069 }
1070
1071 #define for_each_event(event, start, end) \
1072 for (event = start; \
1073 (unsigned long)event < (unsigned long)end; \
1074 event++)
1075
1076 #ifdef CONFIG_MODULES
1077
1078 static LIST_HEAD(ftrace_module_file_list);
1079
1080 /*
1081 * Modules must own their file_operations to keep up with
1082 * reference counting.
1083 */
1084 struct ftrace_module_file_ops {
1085 struct list_head list;
1086 struct module *mod;
1087 struct file_operations id;
1088 struct file_operations enable;
1089 struct file_operations format;
1090 struct file_operations filter;
1091 };
1092
1093 static struct ftrace_module_file_ops *
1094 trace_create_file_ops(struct module *mod)
1095 {
1096 struct ftrace_module_file_ops *file_ops;
1097
1098 /*
1099 * This is a bit of a PITA. To allow for correct reference
1100 * counting, modules must "own" their file_operations.
1101 * To do this, we allocate the file operations that will be
1102 * used in the event directory.
1103 */
1104
1105 file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1106 if (!file_ops)
1107 return NULL;
1108
1109 file_ops->mod = mod;
1110
1111 file_ops->id = ftrace_event_id_fops;
1112 file_ops->id.owner = mod;
1113
1114 file_ops->enable = ftrace_enable_fops;
1115 file_ops->enable.owner = mod;
1116
1117 file_ops->filter = ftrace_event_filter_fops;
1118 file_ops->filter.owner = mod;
1119
1120 file_ops->format = ftrace_event_format_fops;
1121 file_ops->format.owner = mod;
1122
1123 list_add(&file_ops->list, &ftrace_module_file_list);
1124
1125 return file_ops;
1126 }
1127
1128 static void trace_module_add_events(struct module *mod)
1129 {
1130 struct ftrace_module_file_ops *file_ops = NULL;
1131 struct ftrace_event_call *call, *start, *end;
1132 struct dentry *d_events;
1133 int ret;
1134
1135 start = mod->trace_events;
1136 end = mod->trace_events + mod->num_trace_events;
1137
1138 if (start == end)
1139 return;
1140
1141 d_events = event_trace_events_dir();
1142 if (!d_events)
1143 return;
1144
1145 for_each_event(call, start, end) {
1146 /* The linker may leave blanks */
1147 if (!call->name)
1148 continue;
1149 if (call->raw_init) {
1150 ret = call->raw_init(call);
1151 if (ret < 0) {
1152 if (ret != -ENOSYS)
1153 pr_warning("Could not initialize trace "
1154 "point events/%s\n", call->name);
1155 continue;
1156 }
1157 }
1158 /*
1159 * This module has events, create file ops for this module
1160 * if not already done.
1161 */
1162 if (!file_ops) {
1163 file_ops = trace_create_file_ops(mod);
1164 if (!file_ops)
1165 return;
1166 }
1167 call->mod = mod;
1168 ret = event_create_dir(call, d_events,
1169 &file_ops->id, &file_ops->enable,
1170 &file_ops->filter, &file_ops->format);
1171 if (!ret)
1172 list_add(&call->list, &ftrace_events);
1173 }
1174 }
1175
1176 static void trace_module_remove_events(struct module *mod)
1177 {
1178 struct ftrace_module_file_ops *file_ops;
1179 struct ftrace_event_call *call, *p;
1180 bool found = false;
1181
1182 down_write(&trace_event_mutex);
1183 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1184 if (call->mod == mod) {
1185 found = true;
1186 __trace_remove_event_call(call);
1187 }
1188 }
1189
1190 /* Now free the file_operations */
1191 list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1192 if (file_ops->mod == mod)
1193 break;
1194 }
1195 if (&file_ops->list != &ftrace_module_file_list) {
1196 list_del(&file_ops->list);
1197 kfree(file_ops);
1198 }
1199
1200 /*
1201 * It is safest to reset the ring buffer if the module being unloaded
1202 * registered any events.
1203 */
1204 if (found)
1205 tracing_reset_current_online_cpus();
1206 up_write(&trace_event_mutex);
1207 }
1208
1209 static int trace_module_notify(struct notifier_block *self,
1210 unsigned long val, void *data)
1211 {
1212 struct module *mod = data;
1213
1214 mutex_lock(&event_mutex);
1215 switch (val) {
1216 case MODULE_STATE_COMING:
1217 trace_module_add_events(mod);
1218 break;
1219 case MODULE_STATE_GOING:
1220 trace_module_remove_events(mod);
1221 break;
1222 }
1223 mutex_unlock(&event_mutex);
1224
1225 return 0;
1226 }
1227 #else
1228 static int trace_module_notify(struct notifier_block *self,
1229 unsigned long val, void *data)
1230 {
1231 return 0;
1232 }
1233 #endif /* CONFIG_MODULES */
1234
1235 static struct notifier_block trace_module_nb = {
1236 .notifier_call = trace_module_notify,
1237 .priority = 0,
1238 };
1239
1240 extern struct ftrace_event_call __start_ftrace_events[];
1241 extern struct ftrace_event_call __stop_ftrace_events[];
1242
1243 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
1244
1245 static __init int setup_trace_event(char *str)
1246 {
1247 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
1248 ring_buffer_expanded = 1;
1249 tracing_selftest_disabled = 1;
1250
1251 return 1;
1252 }
1253 __setup("trace_event=", setup_trace_event);
1254
1255 static __init int event_trace_init(void)
1256 {
1257 struct ftrace_event_call *call;
1258 struct dentry *d_tracer;
1259 struct dentry *entry;
1260 struct dentry *d_events;
1261 int ret;
1262 char *buf = bootup_event_buf;
1263 char *token;
1264
1265 d_tracer = tracing_init_dentry();
1266 if (!d_tracer)
1267 return 0;
1268
1269 entry = debugfs_create_file("available_events", 0444, d_tracer,
1270 (void *)&show_event_seq_ops,
1271 &ftrace_avail_fops);
1272 if (!entry)
1273 pr_warning("Could not create debugfs "
1274 "'available_events' entry\n");
1275
1276 entry = debugfs_create_file("set_event", 0644, d_tracer,
1277 (void *)&show_set_event_seq_ops,
1278 &ftrace_set_event_fops);
1279 if (!entry)
1280 pr_warning("Could not create debugfs "
1281 "'set_event' entry\n");
1282
1283 d_events = event_trace_events_dir();
1284 if (!d_events)
1285 return 0;
1286
1287 /* ring buffer internal formats */
1288 trace_create_file("header_page", 0444, d_events,
1289 ring_buffer_print_page_header,
1290 &ftrace_show_header_fops);
1291
1292 trace_create_file("header_event", 0444, d_events,
1293 ring_buffer_print_entry_header,
1294 &ftrace_show_header_fops);
1295
1296 trace_create_file("enable", 0644, d_events,
1297 NULL, &ftrace_system_enable_fops);
1298
1299 for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
1300 /* The linker may leave blanks */
1301 if (!call->name)
1302 continue;
1303 if (call->raw_init) {
1304 ret = call->raw_init(call);
1305 if (ret < 0) {
1306 if (ret != -ENOSYS)
1307 pr_warning("Could not initialize trace "
1308 "point events/%s\n", call->name);
1309 continue;
1310 }
1311 }
1312 ret = event_create_dir(call, d_events, &ftrace_event_id_fops,
1313 &ftrace_enable_fops,
1314 &ftrace_event_filter_fops,
1315 &ftrace_event_format_fops);
1316 if (!ret)
1317 list_add(&call->list, &ftrace_events);
1318 }
1319
1320 while (true) {
1321 token = strsep(&buf, ",");
1322
1323 if (!token)
1324 break;
1325 if (!*token)
1326 continue;
1327
1328 ret = ftrace_set_clr_event(token, 1);
1329 if (ret)
1330 pr_warning("Failed to enable trace event: %s\n", token);
1331 }
1332
1333 ret = register_module_notifier(&trace_module_nb);
1334 if (ret)
1335 pr_warning("Failed to register trace events module notifier\n");
1336
1337 return 0;
1338 }
1339 fs_initcall(event_trace_init);
1340
1341 #ifdef CONFIG_FTRACE_STARTUP_TEST
1342
1343 static DEFINE_SPINLOCK(test_spinlock);
1344 static DEFINE_SPINLOCK(test_spinlock_irq);
1345 static DEFINE_MUTEX(test_mutex);
1346
1347 static __init void test_work(struct work_struct *dummy)
1348 {
1349 spin_lock(&test_spinlock);
1350 spin_lock_irq(&test_spinlock_irq);
1351 udelay(1);
1352 spin_unlock_irq(&test_spinlock_irq);
1353 spin_unlock(&test_spinlock);
1354
1355 mutex_lock(&test_mutex);
1356 msleep(1);
1357 mutex_unlock(&test_mutex);
1358 }
1359
1360 static __init int event_test_thread(void *unused)
1361 {
1362 void *test_malloc;
1363
1364 test_malloc = kmalloc(1234, GFP_KERNEL);
1365 if (!test_malloc)
1366 pr_info("failed to kmalloc\n");
1367
1368 schedule_on_each_cpu(test_work);
1369
1370 kfree(test_malloc);
1371
1372 set_current_state(TASK_INTERRUPTIBLE);
1373 while (!kthread_should_stop())
1374 schedule();
1375
1376 return 0;
1377 }
1378
1379 /*
1380 * Do various things that may trigger events.
1381 */
1382 static __init void event_test_stuff(void)
1383 {
1384 struct task_struct *test_thread;
1385
1386 test_thread = kthread_run(event_test_thread, NULL, "test-events");
1387 msleep(1);
1388 kthread_stop(test_thread);
1389 }
1390
1391 /*
1392 * For every trace event defined, we will test each trace point separately,
1393 * and then by groups, and finally all trace points.
1394 */
1395 static __init void event_trace_self_tests(void)
1396 {
1397 struct ftrace_event_call *call;
1398 struct event_subsystem *system;
1399 int ret;
1400
1401 pr_info("Running tests on trace events:\n");
1402
1403 list_for_each_entry(call, &ftrace_events, list) {
1404
1405 /* Only test those that have a probe */
1406 if (!call->class || !call->class->probe)
1407 continue;
1408
1409 /*
1410 * Testing syscall events here is pretty useless, but
1411 * we still do it if configured. But this is time consuming.
1412 * What we really need is a user thread to perform the
1413 * syscalls as we test.
1414 */
1415 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
1416 if (call->class->system &&
1417 strcmp(call->class->system, "syscalls") == 0)
1418 continue;
1419 #endif
1420
1421 pr_info("Testing event %s: ", call->name);
1422
1423 /*
1424 * If an event is already enabled, someone is using
1425 * it and the self test should not be on.
1426 */
1427 if (call->enabled) {
1428 pr_warning("Enabled event during self test!\n");
1429 WARN_ON_ONCE(1);
1430 continue;
1431 }
1432
1433 ftrace_event_enable_disable(call, 1);
1434 event_test_stuff();
1435 ftrace_event_enable_disable(call, 0);
1436
1437 pr_cont("OK\n");
1438 }
1439
1440 /* Now test at the sub system level */
1441
1442 pr_info("Running tests on trace event systems:\n");
1443
1444 list_for_each_entry(system, &event_subsystems, list) {
1445
1446 /* the ftrace system is special, skip it */
1447 if (strcmp(system->name, "ftrace") == 0)
1448 continue;
1449
1450 pr_info("Testing event system %s: ", system->name);
1451
1452 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
1453 if (WARN_ON_ONCE(ret)) {
1454 pr_warning("error enabling system %s\n",
1455 system->name);
1456 continue;
1457 }
1458
1459 event_test_stuff();
1460
1461 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
1462 if (WARN_ON_ONCE(ret))
1463 pr_warning("error disabling system %s\n",
1464 system->name);
1465
1466 pr_cont("OK\n");
1467 }
1468
1469 /* Test with all events enabled */
1470
1471 pr_info("Running tests on all trace events:\n");
1472 pr_info("Testing all events: ");
1473
1474 ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
1475 if (WARN_ON_ONCE(ret)) {
1476 pr_warning("error enabling all events\n");
1477 return;
1478 }
1479
1480 event_test_stuff();
1481
1482 /* reset sysname */
1483 ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
1484 if (WARN_ON_ONCE(ret)) {
1485 pr_warning("error disabling all events\n");
1486 return;
1487 }
1488
1489 pr_cont("OK\n");
1490 }
1491
1492 #ifdef CONFIG_FUNCTION_TRACER
1493
1494 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
1495
1496 static void
1497 function_test_events_call(unsigned long ip, unsigned long parent_ip)
1498 {
1499 struct ring_buffer_event *event;
1500 struct ring_buffer *buffer;
1501 struct ftrace_entry *entry;
1502 unsigned long flags;
1503 long disabled;
1504 int resched;
1505 int cpu;
1506 int pc;
1507
1508 pc = preempt_count();
1509 resched = ftrace_preempt_disable();
1510 cpu = raw_smp_processor_id();
1511 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
1512
1513 if (disabled != 1)
1514 goto out;
1515
1516 local_save_flags(flags);
1517
1518 event = trace_current_buffer_lock_reserve(&buffer,
1519 TRACE_FN, sizeof(*entry),
1520 flags, pc);
1521 if (!event)
1522 goto out;
1523 entry = ring_buffer_event_data(event);
1524 entry->ip = ip;
1525 entry->parent_ip = parent_ip;
1526
1527 trace_nowake_buffer_unlock_commit(buffer, event, flags, pc);
1528
1529 out:
1530 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
1531 ftrace_preempt_enable(resched);
1532 }
1533
1534 static struct ftrace_ops trace_ops __initdata =
1535 {
1536 .func = function_test_events_call,
1537 };
1538
1539 static __init void event_trace_self_test_with_function(void)
1540 {
1541 register_ftrace_function(&trace_ops);
1542 pr_info("Running tests again, along with the function tracer\n");
1543 event_trace_self_tests();
1544 unregister_ftrace_function(&trace_ops);
1545 }
1546 #else
1547 static __init void event_trace_self_test_with_function(void)
1548 {
1549 }
1550 #endif
1551
1552 static __init int event_trace_self_tests_init(void)
1553 {
1554 if (!tracing_selftest_disabled) {
1555 event_trace_self_tests();
1556 event_trace_self_test_with_function();
1557 }
1558
1559 return 0;
1560 }
1561
1562 late_initcall(event_trace_self_tests_init);
1563
1564 #endif
Linux kernel - Deliverables
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