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Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[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/delay.h>
19
20 #include <asm/setup.h>
21
22 #include "trace_output.h"
23
24 #undef TRACE_SYSTEM
25 #define TRACE_SYSTEM "TRACE_SYSTEM"
26
27 DEFINE_MUTEX(event_mutex);
28
29 LIST_HEAD(ftrace_events);
30
31 int trace_define_field(struct ftrace_event_call *call, const char *type,
32 const char *name, int offset, int size, int is_signed,
33 int filter_type)
34 {
35 struct ftrace_event_field *field;
36
37 field = kzalloc(sizeof(*field), GFP_KERNEL);
38 if (!field)
39 goto err;
40
41 field->name = kstrdup(name, GFP_KERNEL);
42 if (!field->name)
43 goto err;
44
45 field->type = kstrdup(type, GFP_KERNEL);
46 if (!field->type)
47 goto err;
48
49 if (filter_type == FILTER_OTHER)
50 field->filter_type = filter_assign_type(type);
51 else
52 field->filter_type = filter_type;
53
54 field->offset = offset;
55 field->size = size;
56 field->is_signed = is_signed;
57
58 list_add(&field->link, &call->fields);
59
60 return 0;
61
62 err:
63 if (field)
64 kfree(field->name);
65 kfree(field);
66
67 return -ENOMEM;
68 }
69 EXPORT_SYMBOL_GPL(trace_define_field);
70
71 #define __common_field(type, item) \
72 ret = trace_define_field(call, #type, "common_" #item, \
73 offsetof(typeof(ent), item), \
74 sizeof(ent.item), \
75 is_signed_type(type), FILTER_OTHER); \
76 if (ret) \
77 return ret;
78
79 static int trace_define_common_fields(struct ftrace_event_call *call)
80 {
81 int ret;
82 struct trace_entry ent;
83
84 __common_field(unsigned short, type);
85 __common_field(unsigned char, flags);
86 __common_field(unsigned char, preempt_count);
87 __common_field(int, pid);
88 __common_field(int, lock_depth);
89
90 return ret;
91 }
92
93 void trace_destroy_fields(struct ftrace_event_call *call)
94 {
95 struct ftrace_event_field *field, *next;
96
97 list_for_each_entry_safe(field, next, &call->fields, link) {
98 list_del(&field->link);
99 kfree(field->type);
100 kfree(field->name);
101 kfree(field);
102 }
103 }
104
105 int trace_event_raw_init(struct ftrace_event_call *call)
106 {
107 int id;
108
109 id = register_ftrace_event(call->event);
110 if (!id)
111 return -ENODEV;
112 call->id = id;
113 INIT_LIST_HEAD(&call->fields);
114
115 return 0;
116 }
117 EXPORT_SYMBOL_GPL(trace_event_raw_init);
118
119 static int ftrace_event_enable_disable(struct ftrace_event_call *call,
120 int enable)
121 {
122 int ret = 0;
123
124 switch (enable) {
125 case 0:
126 if (call->enabled) {
127 call->enabled = 0;
128 tracing_stop_cmdline_record();
129 call->unregfunc(call);
130 }
131 break;
132 case 1:
133 if (!call->enabled) {
134 tracing_start_cmdline_record();
135 ret = call->regfunc(call);
136 if (ret) {
137 tracing_stop_cmdline_record();
138 pr_info("event trace: Could not enable event "
139 "%s\n", call->name);
140 break;
141 }
142 call->enabled = 1;
143 }
144 break;
145 }
146
147 return ret;
148 }
149
150 static void ftrace_clear_events(void)
151 {
152 struct ftrace_event_call *call;
153
154 mutex_lock(&event_mutex);
155 list_for_each_entry(call, &ftrace_events, list) {
156 ftrace_event_enable_disable(call, 0);
157 }
158 mutex_unlock(&event_mutex);
159 }
160
161 /*
162 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
163 */
164 static int __ftrace_set_clr_event(const char *match, const char *sub,
165 const char *event, int set)
166 {
167 struct ftrace_event_call *call;
168 int ret = -EINVAL;
169
170 mutex_lock(&event_mutex);
171 list_for_each_entry(call, &ftrace_events, list) {
172
173 if (!call->name || !call->regfunc)
174 continue;
175
176 if (match &&
177 strcmp(match, call->name) != 0 &&
178 strcmp(match, call->system) != 0)
179 continue;
180
181 if (sub && strcmp(sub, call->system) != 0)
182 continue;
183
184 if (event && strcmp(event, call->name) != 0)
185 continue;
186
187 ftrace_event_enable_disable(call, set);
188
189 ret = 0;
190 }
191 mutex_unlock(&event_mutex);
192
193 return ret;
194 }
195
196 static int ftrace_set_clr_event(char *buf, int set)
197 {
198 char *event = NULL, *sub = NULL, *match;
199
200 /*
201 * The buf format can be <subsystem>:<event-name>
202 * *:<event-name> means any event by that name.
203 * :<event-name> is the same.
204 *
205 * <subsystem>:* means all events in that subsystem
206 * <subsystem>: means the same.
207 *
208 * <name> (no ':') means all events in a subsystem with
209 * the name <name> or any event that matches <name>
210 */
211
212 match = strsep(&buf, ":");
213 if (buf) {
214 sub = match;
215 event = buf;
216 match = NULL;
217
218 if (!strlen(sub) || strcmp(sub, "*") == 0)
219 sub = NULL;
220 if (!strlen(event) || strcmp(event, "*") == 0)
221 event = NULL;
222 }
223
224 return __ftrace_set_clr_event(match, sub, event, set);
225 }
226
227 /**
228 * trace_set_clr_event - enable or disable an event
229 * @system: system name to match (NULL for any system)
230 * @event: event name to match (NULL for all events, within system)
231 * @set: 1 to enable, 0 to disable
232 *
233 * This is a way for other parts of the kernel to enable or disable
234 * event recording.
235 *
236 * Returns 0 on success, -EINVAL if the parameters do not match any
237 * registered events.
238 */
239 int trace_set_clr_event(const char *system, const char *event, int set)
240 {
241 return __ftrace_set_clr_event(NULL, system, event, set);
242 }
243
244 /* 128 should be much more than enough */
245 #define EVENT_BUF_SIZE 127
246
247 static ssize_t
248 ftrace_event_write(struct file *file, const char __user *ubuf,
249 size_t cnt, loff_t *ppos)
250 {
251 struct trace_parser parser;
252 ssize_t read, ret;
253
254 if (!cnt)
255 return 0;
256
257 ret = tracing_update_buffers();
258 if (ret < 0)
259 return ret;
260
261 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
262 return -ENOMEM;
263
264 read = trace_get_user(&parser, ubuf, cnt, ppos);
265
266 if (read >= 0 && trace_parser_loaded((&parser))) {
267 int set = 1;
268
269 if (*parser.buffer == '!')
270 set = 0;
271
272 parser.buffer[parser.idx] = 0;
273
274 ret = ftrace_set_clr_event(parser.buffer + !set, set);
275 if (ret)
276 goto out_put;
277 }
278
279 ret = read;
280
281 out_put:
282 trace_parser_put(&parser);
283
284 return ret;
285 }
286
287 static void *
288 t_next(struct seq_file *m, void *v, loff_t *pos)
289 {
290 struct ftrace_event_call *call = v;
291
292 (*pos)++;
293
294 list_for_each_entry_continue(call, &ftrace_events, list) {
295 /*
296 * The ftrace subsystem is for showing formats only.
297 * They can not be enabled or disabled via the event files.
298 */
299 if (call->regfunc)
300 return call;
301 }
302
303 return NULL;
304 }
305
306 static void *t_start(struct seq_file *m, loff_t *pos)
307 {
308 struct ftrace_event_call *call;
309 loff_t l;
310
311 mutex_lock(&event_mutex);
312
313 call = list_entry(&ftrace_events, struct ftrace_event_call, list);
314 for (l = 0; l <= *pos; ) {
315 call = t_next(m, call, &l);
316 if (!call)
317 break;
318 }
319 return call;
320 }
321
322 static void *
323 s_next(struct seq_file *m, void *v, loff_t *pos)
324 {
325 struct ftrace_event_call *call = v;
326
327 (*pos)++;
328
329 list_for_each_entry_continue(call, &ftrace_events, list) {
330 if (call->enabled)
331 return call;
332 }
333
334 return NULL;
335 }
336
337 static void *s_start(struct seq_file *m, loff_t *pos)
338 {
339 struct ftrace_event_call *call;
340 loff_t l;
341
342 mutex_lock(&event_mutex);
343
344 call = list_entry(&ftrace_events, struct ftrace_event_call, list);
345 for (l = 0; l <= *pos; ) {
346 call = s_next(m, call, &l);
347 if (!call)
348 break;
349 }
350 return call;
351 }
352
353 static int t_show(struct seq_file *m, void *v)
354 {
355 struct ftrace_event_call *call = v;
356
357 if (strcmp(call->system, TRACE_SYSTEM) != 0)
358 seq_printf(m, "%s:", call->system);
359 seq_printf(m, "%s\n", call->name);
360
361 return 0;
362 }
363
364 static void t_stop(struct seq_file *m, void *p)
365 {
366 mutex_unlock(&event_mutex);
367 }
368
369 static int
370 ftrace_event_seq_open(struct inode *inode, struct file *file)
371 {
372 const struct seq_operations *seq_ops;
373
374 if ((file->f_mode & FMODE_WRITE) &&
375 (file->f_flags & O_TRUNC))
376 ftrace_clear_events();
377
378 seq_ops = inode->i_private;
379 return seq_open(file, seq_ops);
380 }
381
382 static ssize_t
383 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
384 loff_t *ppos)
385 {
386 struct ftrace_event_call *call = filp->private_data;
387 char *buf;
388
389 if (call->enabled)
390 buf = "1\n";
391 else
392 buf = "0\n";
393
394 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
395 }
396
397 static ssize_t
398 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
399 loff_t *ppos)
400 {
401 struct ftrace_event_call *call = filp->private_data;
402 char buf[64];
403 unsigned long val;
404 int ret;
405
406 if (cnt >= sizeof(buf))
407 return -EINVAL;
408
409 if (copy_from_user(&buf, ubuf, cnt))
410 return -EFAULT;
411
412 buf[cnt] = 0;
413
414 ret = strict_strtoul(buf, 10, &val);
415 if (ret < 0)
416 return ret;
417
418 ret = tracing_update_buffers();
419 if (ret < 0)
420 return ret;
421
422 switch (val) {
423 case 0:
424 case 1:
425 mutex_lock(&event_mutex);
426 ret = ftrace_event_enable_disable(call, val);
427 mutex_unlock(&event_mutex);
428 break;
429
430 default:
431 return -EINVAL;
432 }
433
434 *ppos += cnt;
435
436 return ret ? ret : cnt;
437 }
438
439 static ssize_t
440 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
441 loff_t *ppos)
442 {
443 const char set_to_char[4] = { '?', '0', '1', 'X' };
444 const char *system = filp->private_data;
445 struct ftrace_event_call *call;
446 char buf[2];
447 int set = 0;
448 int ret;
449
450 mutex_lock(&event_mutex);
451 list_for_each_entry(call, &ftrace_events, list) {
452 if (!call->name || !call->regfunc)
453 continue;
454
455 if (system && strcmp(call->system, system) != 0)
456 continue;
457
458 /*
459 * We need to find out if all the events are set
460 * or if all events or cleared, or if we have
461 * a mixture.
462 */
463 set |= (1 << !!call->enabled);
464
465 /*
466 * If we have a mixture, no need to look further.
467 */
468 if (set == 3)
469 break;
470 }
471 mutex_unlock(&event_mutex);
472
473 buf[0] = set_to_char[set];
474 buf[1] = '\n';
475
476 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
477
478 return ret;
479 }
480
481 static ssize_t
482 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
483 loff_t *ppos)
484 {
485 const char *system = filp->private_data;
486 unsigned long val;
487 char buf[64];
488 ssize_t ret;
489
490 if (cnt >= sizeof(buf))
491 return -EINVAL;
492
493 if (copy_from_user(&buf, ubuf, cnt))
494 return -EFAULT;
495
496 buf[cnt] = 0;
497
498 ret = strict_strtoul(buf, 10, &val);
499 if (ret < 0)
500 return ret;
501
502 ret = tracing_update_buffers();
503 if (ret < 0)
504 return ret;
505
506 if (val != 0 && val != 1)
507 return -EINVAL;
508
509 ret = __ftrace_set_clr_event(NULL, system, NULL, val);
510 if (ret)
511 goto out;
512
513 ret = cnt;
514
515 out:
516 *ppos += cnt;
517
518 return ret;
519 }
520
521 static ssize_t
522 event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
523 loff_t *ppos)
524 {
525 struct ftrace_event_call *call = filp->private_data;
526 struct ftrace_event_field *field;
527 struct trace_seq *s;
528 int common_field_count = 5;
529 char *buf;
530 int r = 0;
531
532 if (*ppos)
533 return 0;
534
535 s = kmalloc(sizeof(*s), GFP_KERNEL);
536 if (!s)
537 return -ENOMEM;
538
539 trace_seq_init(s);
540
541 trace_seq_printf(s, "name: %s\n", call->name);
542 trace_seq_printf(s, "ID: %d\n", call->id);
543 trace_seq_printf(s, "format:\n");
544
545 list_for_each_entry_reverse(field, &call->fields, link) {
546 /*
547 * Smartly shows the array type(except dynamic array).
548 * Normal:
549 * field:TYPE VAR
550 * If TYPE := TYPE[LEN], it is shown:
551 * field:TYPE VAR[LEN]
552 */
553 const char *array_descriptor = strchr(field->type, '[');
554
555 if (!strncmp(field->type, "__data_loc", 10))
556 array_descriptor = NULL;
557
558 if (!array_descriptor) {
559 r = trace_seq_printf(s, "\tfield:%s %s;\toffset:%u;"
560 "\tsize:%u;\tsigned:%d;\n",
561 field->type, field->name, field->offset,
562 field->size, !!field->is_signed);
563 } else {
564 r = trace_seq_printf(s, "\tfield:%.*s %s%s;\toffset:%u;"
565 "\tsize:%u;\tsigned:%d;\n",
566 (int)(array_descriptor - field->type),
567 field->type, field->name,
568 array_descriptor, field->offset,
569 field->size, !!field->is_signed);
570 }
571
572 if (--common_field_count == 0)
573 r = trace_seq_printf(s, "\n");
574
575 if (!r)
576 break;
577 }
578
579 if (r)
580 r = trace_seq_printf(s, "\nprint fmt: %s\n",
581 call->print_fmt);
582
583 if (!r) {
584 /*
585 * ug! The format output is bigger than a PAGE!!
586 */
587 buf = "FORMAT TOO BIG\n";
588 r = simple_read_from_buffer(ubuf, cnt, ppos,
589 buf, strlen(buf));
590 goto out;
591 }
592
593 r = simple_read_from_buffer(ubuf, cnt, ppos,
594 s->buffer, s->len);
595 out:
596 kfree(s);
597 return r;
598 }
599
600 static ssize_t
601 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
602 {
603 struct ftrace_event_call *call = filp->private_data;
604 struct trace_seq *s;
605 int r;
606
607 if (*ppos)
608 return 0;
609
610 s = kmalloc(sizeof(*s), GFP_KERNEL);
611 if (!s)
612 return -ENOMEM;
613
614 trace_seq_init(s);
615 trace_seq_printf(s, "%d\n", call->id);
616
617 r = simple_read_from_buffer(ubuf, cnt, ppos,
618 s->buffer, s->len);
619 kfree(s);
620 return r;
621 }
622
623 static ssize_t
624 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
625 loff_t *ppos)
626 {
627 struct ftrace_event_call *call = filp->private_data;
628 struct trace_seq *s;
629 int r;
630
631 if (*ppos)
632 return 0;
633
634 s = kmalloc(sizeof(*s), GFP_KERNEL);
635 if (!s)
636 return -ENOMEM;
637
638 trace_seq_init(s);
639
640 print_event_filter(call, s);
641 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
642
643 kfree(s);
644
645 return r;
646 }
647
648 static ssize_t
649 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
650 loff_t *ppos)
651 {
652 struct ftrace_event_call *call = filp->private_data;
653 char *buf;
654 int err;
655
656 if (cnt >= PAGE_SIZE)
657 return -EINVAL;
658
659 buf = (char *)__get_free_page(GFP_TEMPORARY);
660 if (!buf)
661 return -ENOMEM;
662
663 if (copy_from_user(buf, ubuf, cnt)) {
664 free_page((unsigned long) buf);
665 return -EFAULT;
666 }
667 buf[cnt] = '\0';
668
669 err = apply_event_filter(call, buf);
670 free_page((unsigned long) buf);
671 if (err < 0)
672 return err;
673
674 *ppos += cnt;
675
676 return cnt;
677 }
678
679 static ssize_t
680 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
681 loff_t *ppos)
682 {
683 struct event_subsystem *system = filp->private_data;
684 struct trace_seq *s;
685 int r;
686
687 if (*ppos)
688 return 0;
689
690 s = kmalloc(sizeof(*s), GFP_KERNEL);
691 if (!s)
692 return -ENOMEM;
693
694 trace_seq_init(s);
695
696 print_subsystem_event_filter(system, s);
697 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
698
699 kfree(s);
700
701 return r;
702 }
703
704 static ssize_t
705 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
706 loff_t *ppos)
707 {
708 struct event_subsystem *system = filp->private_data;
709 char *buf;
710 int err;
711
712 if (cnt >= PAGE_SIZE)
713 return -EINVAL;
714
715 buf = (char *)__get_free_page(GFP_TEMPORARY);
716 if (!buf)
717 return -ENOMEM;
718
719 if (copy_from_user(buf, ubuf, cnt)) {
720 free_page((unsigned long) buf);
721 return -EFAULT;
722 }
723 buf[cnt] = '\0';
724
725 err = apply_subsystem_event_filter(system, buf);
726 free_page((unsigned long) buf);
727 if (err < 0)
728 return err;
729
730 *ppos += cnt;
731
732 return cnt;
733 }
734
735 static ssize_t
736 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
737 {
738 int (*func)(struct trace_seq *s) = filp->private_data;
739 struct trace_seq *s;
740 int r;
741
742 if (*ppos)
743 return 0;
744
745 s = kmalloc(sizeof(*s), GFP_KERNEL);
746 if (!s)
747 return -ENOMEM;
748
749 trace_seq_init(s);
750
751 func(s);
752 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
753
754 kfree(s);
755
756 return r;
757 }
758
759 static const struct seq_operations show_event_seq_ops = {
760 .start = t_start,
761 .next = t_next,
762 .show = t_show,
763 .stop = t_stop,
764 };
765
766 static const struct seq_operations show_set_event_seq_ops = {
767 .start = s_start,
768 .next = s_next,
769 .show = t_show,
770 .stop = t_stop,
771 };
772
773 static const struct file_operations ftrace_avail_fops = {
774 .open = ftrace_event_seq_open,
775 .read = seq_read,
776 .llseek = seq_lseek,
777 .release = seq_release,
778 };
779
780 static const struct file_operations ftrace_set_event_fops = {
781 .open = ftrace_event_seq_open,
782 .read = seq_read,
783 .write = ftrace_event_write,
784 .llseek = seq_lseek,
785 .release = seq_release,
786 };
787
788 static const struct file_operations ftrace_enable_fops = {
789 .open = tracing_open_generic,
790 .read = event_enable_read,
791 .write = event_enable_write,
792 };
793
794 static const struct file_operations ftrace_event_format_fops = {
795 .open = tracing_open_generic,
796 .read = event_format_read,
797 };
798
799 static const struct file_operations ftrace_event_id_fops = {
800 .open = tracing_open_generic,
801 .read = event_id_read,
802 };
803
804 static const struct file_operations ftrace_event_filter_fops = {
805 .open = tracing_open_generic,
806 .read = event_filter_read,
807 .write = event_filter_write,
808 };
809
810 static const struct file_operations ftrace_subsystem_filter_fops = {
811 .open = tracing_open_generic,
812 .read = subsystem_filter_read,
813 .write = subsystem_filter_write,
814 };
815
816 static const struct file_operations ftrace_system_enable_fops = {
817 .open = tracing_open_generic,
818 .read = system_enable_read,
819 .write = system_enable_write,
820 };
821
822 static const struct file_operations ftrace_show_header_fops = {
823 .open = tracing_open_generic,
824 .read = show_header,
825 };
826
827 static struct dentry *event_trace_events_dir(void)
828 {
829 static struct dentry *d_tracer;
830 static struct dentry *d_events;
831
832 if (d_events)
833 return d_events;
834
835 d_tracer = tracing_init_dentry();
836 if (!d_tracer)
837 return NULL;
838
839 d_events = debugfs_create_dir("events", d_tracer);
840 if (!d_events)
841 pr_warning("Could not create debugfs "
842 "'events' directory\n");
843
844 return d_events;
845 }
846
847 static LIST_HEAD(event_subsystems);
848
849 static struct dentry *
850 event_subsystem_dir(const char *name, struct dentry *d_events)
851 {
852 struct event_subsystem *system;
853 struct dentry *entry;
854
855 /* First see if we did not already create this dir */
856 list_for_each_entry(system, &event_subsystems, list) {
857 if (strcmp(system->name, name) == 0) {
858 system->nr_events++;
859 return system->entry;
860 }
861 }
862
863 /* need to create new entry */
864 system = kmalloc(sizeof(*system), GFP_KERNEL);
865 if (!system) {
866 pr_warning("No memory to create event subsystem %s\n",
867 name);
868 return d_events;
869 }
870
871 system->entry = debugfs_create_dir(name, d_events);
872 if (!system->entry) {
873 pr_warning("Could not create event subsystem %s\n",
874 name);
875 kfree(system);
876 return d_events;
877 }
878
879 system->nr_events = 1;
880 system->name = kstrdup(name, GFP_KERNEL);
881 if (!system->name) {
882 debugfs_remove(system->entry);
883 kfree(system);
884 return d_events;
885 }
886
887 list_add(&system->list, &event_subsystems);
888
889 system->filter = NULL;
890
891 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
892 if (!system->filter) {
893 pr_warning("Could not allocate filter for subsystem "
894 "'%s'\n", name);
895 return system->entry;
896 }
897
898 entry = debugfs_create_file("filter", 0644, system->entry, system,
899 &ftrace_subsystem_filter_fops);
900 if (!entry) {
901 kfree(system->filter);
902 system->filter = NULL;
903 pr_warning("Could not create debugfs "
904 "'%s/filter' entry\n", name);
905 }
906
907 trace_create_file("enable", 0644, system->entry,
908 (void *)system->name,
909 &ftrace_system_enable_fops);
910
911 return system->entry;
912 }
913
914 static int
915 event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
916 const struct file_operations *id,
917 const struct file_operations *enable,
918 const struct file_operations *filter,
919 const struct file_operations *format)
920 {
921 int ret;
922
923 /*
924 * If the trace point header did not define TRACE_SYSTEM
925 * then the system would be called "TRACE_SYSTEM".
926 */
927 if (strcmp(call->system, TRACE_SYSTEM) != 0)
928 d_events = event_subsystem_dir(call->system, d_events);
929
930 call->dir = debugfs_create_dir(call->name, d_events);
931 if (!call->dir) {
932 pr_warning("Could not create debugfs "
933 "'%s' directory\n", call->name);
934 return -1;
935 }
936
937 if (call->regfunc)
938 trace_create_file("enable", 0644, call->dir, call,
939 enable);
940
941 if (call->id && call->profile_enable)
942 trace_create_file("id", 0444, call->dir, call,
943 id);
944
945 if (call->define_fields) {
946 ret = trace_define_common_fields(call);
947 if (!ret)
948 ret = call->define_fields(call);
949 if (ret < 0) {
950 pr_warning("Could not initialize trace point"
951 " events/%s\n", call->name);
952 return ret;
953 }
954 trace_create_file("filter", 0644, call->dir, call,
955 filter);
956 }
957
958 trace_create_file("format", 0444, call->dir, call,
959 format);
960
961 return 0;
962 }
963
964 static int __trace_add_event_call(struct ftrace_event_call *call)
965 {
966 struct dentry *d_events;
967 int ret;
968
969 if (!call->name)
970 return -EINVAL;
971
972 if (call->raw_init) {
973 ret = call->raw_init(call);
974 if (ret < 0) {
975 if (ret != -ENOSYS)
976 pr_warning("Could not initialize trace "
977 "events/%s\n", call->name);
978 return ret;
979 }
980 }
981
982 d_events = event_trace_events_dir();
983 if (!d_events)
984 return -ENOENT;
985
986 ret = event_create_dir(call, d_events, &ftrace_event_id_fops,
987 &ftrace_enable_fops, &ftrace_event_filter_fops,
988 &ftrace_event_format_fops);
989 if (!ret)
990 list_add(&call->list, &ftrace_events);
991
992 return ret;
993 }
994
995 /* Add an additional event_call dynamically */
996 int trace_add_event_call(struct ftrace_event_call *call)
997 {
998 int ret;
999 mutex_lock(&event_mutex);
1000 ret = __trace_add_event_call(call);
1001 mutex_unlock(&event_mutex);
1002 return ret;
1003 }
1004
1005 static void remove_subsystem_dir(const char *name)
1006 {
1007 struct event_subsystem *system;
1008
1009 if (strcmp(name, TRACE_SYSTEM) == 0)
1010 return;
1011
1012 list_for_each_entry(system, &event_subsystems, list) {
1013 if (strcmp(system->name, name) == 0) {
1014 if (!--system->nr_events) {
1015 struct event_filter *filter = system->filter;
1016
1017 debugfs_remove_recursive(system->entry);
1018 list_del(&system->list);
1019 if (filter) {
1020 kfree(filter->filter_string);
1021 kfree(filter);
1022 }
1023 kfree(system->name);
1024 kfree(system);
1025 }
1026 break;
1027 }
1028 }
1029 }
1030
1031 /*
1032 * Must be called under locking both of event_mutex and trace_event_mutex.
1033 */
1034 static void __trace_remove_event_call(struct ftrace_event_call *call)
1035 {
1036 ftrace_event_enable_disable(call, 0);
1037 if (call->event)
1038 __unregister_ftrace_event(call->event);
1039 debugfs_remove_recursive(call->dir);
1040 list_del(&call->list);
1041 trace_destroy_fields(call);
1042 destroy_preds(call);
1043 remove_subsystem_dir(call->system);
1044 }
1045
1046 /* Remove an event_call */
1047 void trace_remove_event_call(struct ftrace_event_call *call)
1048 {
1049 mutex_lock(&event_mutex);
1050 down_write(&trace_event_mutex);
1051 __trace_remove_event_call(call);
1052 up_write(&trace_event_mutex);
1053 mutex_unlock(&event_mutex);
1054 }
1055
1056 #define for_each_event(event, start, end) \
1057 for (event = start; \
1058 (unsigned long)event < (unsigned long)end; \
1059 event++)
1060
1061 #ifdef CONFIG_MODULES
1062
1063 static LIST_HEAD(ftrace_module_file_list);
1064
1065 /*
1066 * Modules must own their file_operations to keep up with
1067 * reference counting.
1068 */
1069 struct ftrace_module_file_ops {
1070 struct list_head list;
1071 struct module *mod;
1072 struct file_operations id;
1073 struct file_operations enable;
1074 struct file_operations format;
1075 struct file_operations filter;
1076 };
1077
1078 static struct ftrace_module_file_ops *
1079 trace_create_file_ops(struct module *mod)
1080 {
1081 struct ftrace_module_file_ops *file_ops;
1082
1083 /*
1084 * This is a bit of a PITA. To allow for correct reference
1085 * counting, modules must "own" their file_operations.
1086 * To do this, we allocate the file operations that will be
1087 * used in the event directory.
1088 */
1089
1090 file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1091 if (!file_ops)
1092 return NULL;
1093
1094 file_ops->mod = mod;
1095
1096 file_ops->id = ftrace_event_id_fops;
1097 file_ops->id.owner = mod;
1098
1099 file_ops->enable = ftrace_enable_fops;
1100 file_ops->enable.owner = mod;
1101
1102 file_ops->filter = ftrace_event_filter_fops;
1103 file_ops->filter.owner = mod;
1104
1105 file_ops->format = ftrace_event_format_fops;
1106 file_ops->format.owner = mod;
1107
1108 list_add(&file_ops->list, &ftrace_module_file_list);
1109
1110 return file_ops;
1111 }
1112
1113 static void trace_module_add_events(struct module *mod)
1114 {
1115 struct ftrace_module_file_ops *file_ops = NULL;
1116 struct ftrace_event_call *call, *start, *end;
1117 struct dentry *d_events;
1118 int ret;
1119
1120 start = mod->trace_events;
1121 end = mod->trace_events + mod->num_trace_events;
1122
1123 if (start == end)
1124 return;
1125
1126 d_events = event_trace_events_dir();
1127 if (!d_events)
1128 return;
1129
1130 for_each_event(call, start, end) {
1131 /* The linker may leave blanks */
1132 if (!call->name)
1133 continue;
1134 if (call->raw_init) {
1135 ret = call->raw_init(call);
1136 if (ret < 0) {
1137 if (ret != -ENOSYS)
1138 pr_warning("Could not initialize trace "
1139 "point events/%s\n", call->name);
1140 continue;
1141 }
1142 }
1143 /*
1144 * This module has events, create file ops for this module
1145 * if not already done.
1146 */
1147 if (!file_ops) {
1148 file_ops = trace_create_file_ops(mod);
1149 if (!file_ops)
1150 return;
1151 }
1152 call->mod = mod;
1153 ret = event_create_dir(call, d_events,
1154 &file_ops->id, &file_ops->enable,
1155 &file_ops->filter, &file_ops->format);
1156 if (!ret)
1157 list_add(&call->list, &ftrace_events);
1158 }
1159 }
1160
1161 static void trace_module_remove_events(struct module *mod)
1162 {
1163 struct ftrace_module_file_ops *file_ops;
1164 struct ftrace_event_call *call, *p;
1165 bool found = false;
1166
1167 down_write(&trace_event_mutex);
1168 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1169 if (call->mod == mod) {
1170 found = true;
1171 __trace_remove_event_call(call);
1172 }
1173 }
1174
1175 /* Now free the file_operations */
1176 list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1177 if (file_ops->mod == mod)
1178 break;
1179 }
1180 if (&file_ops->list != &ftrace_module_file_list) {
1181 list_del(&file_ops->list);
1182 kfree(file_ops);
1183 }
1184
1185 /*
1186 * It is safest to reset the ring buffer if the module being unloaded
1187 * registered any events.
1188 */
1189 if (found)
1190 tracing_reset_current_online_cpus();
1191 up_write(&trace_event_mutex);
1192 }
1193
1194 static int trace_module_notify(struct notifier_block *self,
1195 unsigned long val, void *data)
1196 {
1197 struct module *mod = data;
1198
1199 mutex_lock(&event_mutex);
1200 switch (val) {
1201 case MODULE_STATE_COMING:
1202 trace_module_add_events(mod);
1203 break;
1204 case MODULE_STATE_GOING:
1205 trace_module_remove_events(mod);
1206 break;
1207 }
1208 mutex_unlock(&event_mutex);
1209
1210 return 0;
1211 }
1212 #else
1213 static int trace_module_notify(struct notifier_block *self,
1214 unsigned long val, void *data)
1215 {
1216 return 0;
1217 }
1218 #endif /* CONFIG_MODULES */
1219
1220 static struct notifier_block trace_module_nb = {
1221 .notifier_call = trace_module_notify,
1222 .priority = 0,
1223 };
1224
1225 extern struct ftrace_event_call __start_ftrace_events[];
1226 extern struct ftrace_event_call __stop_ftrace_events[];
1227
1228 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
1229
1230 static __init int setup_trace_event(char *str)
1231 {
1232 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
1233 ring_buffer_expanded = 1;
1234 tracing_selftest_disabled = 1;
1235
1236 return 1;
1237 }
1238 __setup("trace_event=", setup_trace_event);
1239
1240 static __init int event_trace_init(void)
1241 {
1242 struct ftrace_event_call *call;
1243 struct dentry *d_tracer;
1244 struct dentry *entry;
1245 struct dentry *d_events;
1246 int ret;
1247 char *buf = bootup_event_buf;
1248 char *token;
1249
1250 d_tracer = tracing_init_dentry();
1251 if (!d_tracer)
1252 return 0;
1253
1254 entry = debugfs_create_file("available_events", 0444, d_tracer,
1255 (void *)&show_event_seq_ops,
1256 &ftrace_avail_fops);
1257 if (!entry)
1258 pr_warning("Could not create debugfs "
1259 "'available_events' entry\n");
1260
1261 entry = debugfs_create_file("set_event", 0644, d_tracer,
1262 (void *)&show_set_event_seq_ops,
1263 &ftrace_set_event_fops);
1264 if (!entry)
1265 pr_warning("Could not create debugfs "
1266 "'set_event' entry\n");
1267
1268 d_events = event_trace_events_dir();
1269 if (!d_events)
1270 return 0;
1271
1272 /* ring buffer internal formats */
1273 trace_create_file("header_page", 0444, d_events,
1274 ring_buffer_print_page_header,
1275 &ftrace_show_header_fops);
1276
1277 trace_create_file("header_event", 0444, d_events,
1278 ring_buffer_print_entry_header,
1279 &ftrace_show_header_fops);
1280
1281 trace_create_file("enable", 0644, d_events,
1282 NULL, &ftrace_system_enable_fops);
1283
1284 for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
1285 /* The linker may leave blanks */
1286 if (!call->name)
1287 continue;
1288 if (call->raw_init) {
1289 ret = call->raw_init(call);
1290 if (ret < 0) {
1291 if (ret != -ENOSYS)
1292 pr_warning("Could not initialize trace "
1293 "point events/%s\n", call->name);
1294 continue;
1295 }
1296 }
1297 ret = event_create_dir(call, d_events, &ftrace_event_id_fops,
1298 &ftrace_enable_fops,
1299 &ftrace_event_filter_fops,
1300 &ftrace_event_format_fops);
1301 if (!ret)
1302 list_add(&call->list, &ftrace_events);
1303 }
1304
1305 while (true) {
1306 token = strsep(&buf, ",");
1307
1308 if (!token)
1309 break;
1310 if (!*token)
1311 continue;
1312
1313 ret = ftrace_set_clr_event(token, 1);
1314 if (ret)
1315 pr_warning("Failed to enable trace event: %s\n", token);
1316 }
1317
1318 ret = register_module_notifier(&trace_module_nb);
1319 if (ret)
1320 pr_warning("Failed to register trace events module notifier\n");
1321
1322 return 0;
1323 }
1324 fs_initcall(event_trace_init);
1325
1326 #ifdef CONFIG_FTRACE_STARTUP_TEST
1327
1328 static DEFINE_SPINLOCK(test_spinlock);
1329 static DEFINE_SPINLOCK(test_spinlock_irq);
1330 static DEFINE_MUTEX(test_mutex);
1331
1332 static __init void test_work(struct work_struct *dummy)
1333 {
1334 spin_lock(&test_spinlock);
1335 spin_lock_irq(&test_spinlock_irq);
1336 udelay(1);
1337 spin_unlock_irq(&test_spinlock_irq);
1338 spin_unlock(&test_spinlock);
1339
1340 mutex_lock(&test_mutex);
1341 msleep(1);
1342 mutex_unlock(&test_mutex);
1343 }
1344
1345 static __init int event_test_thread(void *unused)
1346 {
1347 void *test_malloc;
1348
1349 test_malloc = kmalloc(1234, GFP_KERNEL);
1350 if (!test_malloc)
1351 pr_info("failed to kmalloc\n");
1352
1353 schedule_on_each_cpu(test_work);
1354
1355 kfree(test_malloc);
1356
1357 set_current_state(TASK_INTERRUPTIBLE);
1358 while (!kthread_should_stop())
1359 schedule();
1360
1361 return 0;
1362 }
1363
1364 /*
1365 * Do various things that may trigger events.
1366 */
1367 static __init void event_test_stuff(void)
1368 {
1369 struct task_struct *test_thread;
1370
1371 test_thread = kthread_run(event_test_thread, NULL, "test-events");
1372 msleep(1);
1373 kthread_stop(test_thread);
1374 }
1375
1376 /*
1377 * For every trace event defined, we will test each trace point separately,
1378 * and then by groups, and finally all trace points.
1379 */
1380 static __init void event_trace_self_tests(void)
1381 {
1382 struct ftrace_event_call *call;
1383 struct event_subsystem *system;
1384 int ret;
1385
1386 pr_info("Running tests on trace events:\n");
1387
1388 list_for_each_entry(call, &ftrace_events, list) {
1389
1390 /* Only test those that have a regfunc */
1391 if (!call->regfunc)
1392 continue;
1393
1394 /*
1395 * Testing syscall events here is pretty useless, but
1396 * we still do it if configured. But this is time consuming.
1397 * What we really need is a user thread to perform the
1398 * syscalls as we test.
1399 */
1400 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
1401 if (call->system &&
1402 strcmp(call->system, "syscalls") == 0)
1403 continue;
1404 #endif
1405
1406 pr_info("Testing event %s: ", call->name);
1407
1408 /*
1409 * If an event is already enabled, someone is using
1410 * it and the self test should not be on.
1411 */
1412 if (call->enabled) {
1413 pr_warning("Enabled event during self test!\n");
1414 WARN_ON_ONCE(1);
1415 continue;
1416 }
1417
1418 ftrace_event_enable_disable(call, 1);
1419 event_test_stuff();
1420 ftrace_event_enable_disable(call, 0);
1421
1422 pr_cont("OK\n");
1423 }
1424
1425 /* Now test at the sub system level */
1426
1427 pr_info("Running tests on trace event systems:\n");
1428
1429 list_for_each_entry(system, &event_subsystems, list) {
1430
1431 /* the ftrace system is special, skip it */
1432 if (strcmp(system->name, "ftrace") == 0)
1433 continue;
1434
1435 pr_info("Testing event system %s: ", system->name);
1436
1437 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
1438 if (WARN_ON_ONCE(ret)) {
1439 pr_warning("error enabling system %s\n",
1440 system->name);
1441 continue;
1442 }
1443
1444 event_test_stuff();
1445
1446 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
1447 if (WARN_ON_ONCE(ret))
1448 pr_warning("error disabling system %s\n",
1449 system->name);
1450
1451 pr_cont("OK\n");
1452 }
1453
1454 /* Test with all events enabled */
1455
1456 pr_info("Running tests on all trace events:\n");
1457 pr_info("Testing all events: ");
1458
1459 ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
1460 if (WARN_ON_ONCE(ret)) {
1461 pr_warning("error enabling all events\n");
1462 return;
1463 }
1464
1465 event_test_stuff();
1466
1467 /* reset sysname */
1468 ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
1469 if (WARN_ON_ONCE(ret)) {
1470 pr_warning("error disabling all events\n");
1471 return;
1472 }
1473
1474 pr_cont("OK\n");
1475 }
1476
1477 #ifdef CONFIG_FUNCTION_TRACER
1478
1479 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
1480
1481 static void
1482 function_test_events_call(unsigned long ip, unsigned long parent_ip)
1483 {
1484 struct ring_buffer_event *event;
1485 struct ring_buffer *buffer;
1486 struct ftrace_entry *entry;
1487 unsigned long flags;
1488 long disabled;
1489 int resched;
1490 int cpu;
1491 int pc;
1492
1493 pc = preempt_count();
1494 resched = ftrace_preempt_disable();
1495 cpu = raw_smp_processor_id();
1496 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
1497
1498 if (disabled != 1)
1499 goto out;
1500
1501 local_save_flags(flags);
1502
1503 event = trace_current_buffer_lock_reserve(&buffer,
1504 TRACE_FN, sizeof(*entry),
1505 flags, pc);
1506 if (!event)
1507 goto out;
1508 entry = ring_buffer_event_data(event);
1509 entry->ip = ip;
1510 entry->parent_ip = parent_ip;
1511
1512 trace_nowake_buffer_unlock_commit(buffer, event, flags, pc);
1513
1514 out:
1515 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
1516 ftrace_preempt_enable(resched);
1517 }
1518
1519 static struct ftrace_ops trace_ops __initdata =
1520 {
1521 .func = function_test_events_call,
1522 };
1523
1524 static __init void event_trace_self_test_with_function(void)
1525 {
1526 register_ftrace_function(&trace_ops);
1527 pr_info("Running tests again, along with the function tracer\n");
1528 event_trace_self_tests();
1529 unregister_ftrace_function(&trace_ops);
1530 }
1531 #else
1532 static __init void event_trace_self_test_with_function(void)
1533 {
1534 }
1535 #endif
1536
1537 static __init int event_trace_self_tests_init(void)
1538 {
1539 if (!tracing_selftest_disabled) {
1540 event_trace_self_tests();
1541 event_trace_self_test_with_function();
1542 }
1543
1544 return 0;
1545 }
1546
1547 late_initcall(event_trace_self_tests_init);
1548
1549 #endif
Linux kernel - Deliverables
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