Merge branch 'master' into for-next
[linux-2.6.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 "trace_output.h"
21
22 #define TRACE_SYSTEM "TRACE_SYSTEM"
23
24 DEFINE_MUTEX(event_mutex);
25
26 LIST_HEAD(ftrace_events);
27
28 int trace_define_field(struct ftrace_event_call *call, char *type,
29                        char *name, int offset, int size, int is_signed)
30 {
31         struct ftrace_event_field *field;
32
33         field = kzalloc(sizeof(*field), GFP_KERNEL);
34         if (!field)
35                 goto err;
36
37         field->name = kstrdup(name, GFP_KERNEL);
38         if (!field->name)
39                 goto err;
40
41         field->type = kstrdup(type, GFP_KERNEL);
42         if (!field->type)
43                 goto err;
44
45         field->offset = offset;
46         field->size = size;
47         field->is_signed = is_signed;
48         list_add(&field->link, &call->fields);
49
50         return 0;
51
52 err:
53         if (field) {
54                 kfree(field->name);
55                 kfree(field->type);
56         }
57         kfree(field);
58
59         return -ENOMEM;
60 }
61 EXPORT_SYMBOL_GPL(trace_define_field);
62
63 #ifdef CONFIG_MODULES
64
65 static void trace_destroy_fields(struct ftrace_event_call *call)
66 {
67         struct ftrace_event_field *field, *next;
68
69         list_for_each_entry_safe(field, next, &call->fields, link) {
70                 list_del(&field->link);
71                 kfree(field->type);
72                 kfree(field->name);
73                 kfree(field);
74         }
75 }
76
77 #endif /* CONFIG_MODULES */
78
79 static void ftrace_event_enable_disable(struct ftrace_event_call *call,
80                                         int enable)
81 {
82         switch (enable) {
83         case 0:
84                 if (call->enabled) {
85                         call->enabled = 0;
86                         tracing_stop_cmdline_record();
87                         call->unregfunc();
88                 }
89                 break;
90         case 1:
91                 if (!call->enabled) {
92                         call->enabled = 1;
93                         tracing_start_cmdline_record();
94                         call->regfunc();
95                 }
96                 break;
97         }
98 }
99
100 static void ftrace_clear_events(void)
101 {
102         struct ftrace_event_call *call;
103
104         mutex_lock(&event_mutex);
105         list_for_each_entry(call, &ftrace_events, list) {
106                 ftrace_event_enable_disable(call, 0);
107         }
108         mutex_unlock(&event_mutex);
109 }
110
111 /*
112  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
113  */
114 static int __ftrace_set_clr_event(const char *match, const char *sub,
115                                   const char *event, int set)
116 {
117         struct ftrace_event_call *call;
118         int ret = -EINVAL;
119
120         mutex_lock(&event_mutex);
121         list_for_each_entry(call, &ftrace_events, list) {
122
123                 if (!call->name || !call->regfunc)
124                         continue;
125
126                 if (match &&
127                     strcmp(match, call->name) != 0 &&
128                     strcmp(match, call->system) != 0)
129                         continue;
130
131                 if (sub && strcmp(sub, call->system) != 0)
132                         continue;
133
134                 if (event && strcmp(event, call->name) != 0)
135                         continue;
136
137                 ftrace_event_enable_disable(call, set);
138
139                 ret = 0;
140         }
141         mutex_unlock(&event_mutex);
142
143         return ret;
144 }
145
146 static int ftrace_set_clr_event(char *buf, int set)
147 {
148         char *event = NULL, *sub = NULL, *match;
149
150         /*
151          * The buf format can be <subsystem>:<event-name>
152          *  *:<event-name> means any event by that name.
153          *  :<event-name> is the same.
154          *
155          *  <subsystem>:* means all events in that subsystem
156          *  <subsystem>: means the same.
157          *
158          *  <name> (no ':') means all events in a subsystem with
159          *  the name <name> or any event that matches <name>
160          */
161
162         match = strsep(&buf, ":");
163         if (buf) {
164                 sub = match;
165                 event = buf;
166                 match = NULL;
167
168                 if (!strlen(sub) || strcmp(sub, "*") == 0)
169                         sub = NULL;
170                 if (!strlen(event) || strcmp(event, "*") == 0)
171                         event = NULL;
172         }
173
174         return __ftrace_set_clr_event(match, sub, event, set);
175 }
176
177 /**
178  * trace_set_clr_event - enable or disable an event
179  * @system: system name to match (NULL for any system)
180  * @event: event name to match (NULL for all events, within system)
181  * @set: 1 to enable, 0 to disable
182  *
183  * This is a way for other parts of the kernel to enable or disable
184  * event recording.
185  *
186  * Returns 0 on success, -EINVAL if the parameters do not match any
187  * registered events.
188  */
189 int trace_set_clr_event(const char *system, const char *event, int set)
190 {
191         return __ftrace_set_clr_event(NULL, system, event, set);
192 }
193
194 /* 128 should be much more than enough */
195 #define EVENT_BUF_SIZE          127
196
197 static ssize_t
198 ftrace_event_write(struct file *file, const char __user *ubuf,
199                    size_t cnt, loff_t *ppos)
200 {
201         size_t read = 0;
202         int i, set = 1;
203         ssize_t ret;
204         char *buf;
205         char ch;
206
207         if (!cnt || cnt < 0)
208                 return 0;
209
210         ret = tracing_update_buffers();
211         if (ret < 0)
212                 return ret;
213
214         ret = get_user(ch, ubuf++);
215         if (ret)
216                 return ret;
217         read++;
218         cnt--;
219
220         /* skip white space */
221         while (cnt && isspace(ch)) {
222                 ret = get_user(ch, ubuf++);
223                 if (ret)
224                         return ret;
225                 read++;
226                 cnt--;
227         }
228
229         /* Only white space found? */
230         if (isspace(ch)) {
231                 file->f_pos += read;
232                 ret = read;
233                 return ret;
234         }
235
236         buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
237         if (!buf)
238                 return -ENOMEM;
239
240         if (cnt > EVENT_BUF_SIZE)
241                 cnt = EVENT_BUF_SIZE;
242
243         i = 0;
244         while (cnt && !isspace(ch)) {
245                 if (!i && ch == '!')
246                         set = 0;
247                 else
248                         buf[i++] = ch;
249
250                 ret = get_user(ch, ubuf++);
251                 if (ret)
252                         goto out_free;
253                 read++;
254                 cnt--;
255         }
256         buf[i] = 0;
257
258         file->f_pos += read;
259
260         ret = ftrace_set_clr_event(buf, set);
261         if (ret)
262                 goto out_free;
263
264         ret = read;
265
266  out_free:
267         kfree(buf);
268
269         return ret;
270 }
271
272 static void *
273 t_next(struct seq_file *m, void *v, loff_t *pos)
274 {
275         struct list_head *list = m->private;
276         struct ftrace_event_call *call;
277
278         (*pos)++;
279
280         for (;;) {
281                 if (list == &ftrace_events)
282                         return NULL;
283
284                 call = list_entry(list, struct ftrace_event_call, list);
285
286                 /*
287                  * The ftrace subsystem is for showing formats only.
288                  * They can not be enabled or disabled via the event files.
289                  */
290                 if (call->regfunc)
291                         break;
292
293                 list = list->next;
294         }
295
296         m->private = list->next;
297
298         return call;
299 }
300
301 static void *t_start(struct seq_file *m, loff_t *pos)
302 {
303         struct ftrace_event_call *call = NULL;
304         loff_t l;
305
306         mutex_lock(&event_mutex);
307
308         m->private = ftrace_events.next;
309         for (l = 0; l <= *pos; ) {
310                 call = t_next(m, NULL, &l);
311                 if (!call)
312                         break;
313         }
314         return call;
315 }
316
317 static void *
318 s_next(struct seq_file *m, void *v, loff_t *pos)
319 {
320         struct list_head *list = m->private;
321         struct ftrace_event_call *call;
322
323         (*pos)++;
324
325  retry:
326         if (list == &ftrace_events)
327                 return NULL;
328
329         call = list_entry(list, struct ftrace_event_call, list);
330
331         if (!call->enabled) {
332                 list = list->next;
333                 goto retry;
334         }
335
336         m->private = list->next;
337
338         return call;
339 }
340
341 static void *s_start(struct seq_file *m, loff_t *pos)
342 {
343         struct ftrace_event_call *call = NULL;
344         loff_t l;
345
346         mutex_lock(&event_mutex);
347
348         m->private = ftrace_events.next;
349         for (l = 0; l <= *pos; ) {
350                 call = s_next(m, NULL, &l);
351                 if (!call)
352                         break;
353         }
354         return call;
355 }
356
357 static int t_show(struct seq_file *m, void *v)
358 {
359         struct ftrace_event_call *call = v;
360
361         if (strcmp(call->system, TRACE_SYSTEM) != 0)
362                 seq_printf(m, "%s:", call->system);
363         seq_printf(m, "%s\n", call->name);
364
365         return 0;
366 }
367
368 static void t_stop(struct seq_file *m, void *p)
369 {
370         mutex_unlock(&event_mutex);
371 }
372
373 static int
374 ftrace_event_seq_open(struct inode *inode, struct file *file)
375 {
376         const struct seq_operations *seq_ops;
377
378         if ((file->f_mode & FMODE_WRITE) &&
379             !(file->f_flags & O_APPEND))
380                 ftrace_clear_events();
381
382         seq_ops = inode->i_private;
383         return seq_open(file, seq_ops);
384 }
385
386 static ssize_t
387 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
388                   loff_t *ppos)
389 {
390         struct ftrace_event_call *call = filp->private_data;
391         char *buf;
392
393         if (call->enabled)
394                 buf = "1\n";
395         else
396                 buf = "0\n";
397
398         return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
399 }
400
401 static ssize_t
402 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
403                    loff_t *ppos)
404 {
405         struct ftrace_event_call *call = filp->private_data;
406         char buf[64];
407         unsigned long val;
408         int ret;
409
410         if (cnt >= sizeof(buf))
411                 return -EINVAL;
412
413         if (copy_from_user(&buf, ubuf, cnt))
414                 return -EFAULT;
415
416         buf[cnt] = 0;
417
418         ret = strict_strtoul(buf, 10, &val);
419         if (ret < 0)
420                 return ret;
421
422         ret = tracing_update_buffers();
423         if (ret < 0)
424                 return ret;
425
426         switch (val) {
427         case 0:
428         case 1:
429                 mutex_lock(&event_mutex);
430                 ftrace_event_enable_disable(call, val);
431                 mutex_unlock(&event_mutex);
432                 break;
433
434         default:
435                 return -EINVAL;
436         }
437
438         *ppos += cnt;
439
440         return cnt;
441 }
442
443 static ssize_t
444 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
445                    loff_t *ppos)
446 {
447         const char set_to_char[4] = { '?', '0', '1', 'X' };
448         const char *system = filp->private_data;
449         struct ftrace_event_call *call;
450         char buf[2];
451         int set = 0;
452         int ret;
453
454         mutex_lock(&event_mutex);
455         list_for_each_entry(call, &ftrace_events, list) {
456                 if (!call->name || !call->regfunc)
457                         continue;
458
459                 if (system && strcmp(call->system, system) != 0)
460                         continue;
461
462                 /*
463                  * We need to find out if all the events are set
464                  * or if all events or cleared, or if we have
465                  * a mixture.
466                  */
467                 set |= (1 << !!call->enabled);
468
469                 /*
470                  * If we have a mixture, no need to look further.
471                  */
472                 if (set == 3)
473                         break;
474         }
475         mutex_unlock(&event_mutex);
476
477         buf[0] = set_to_char[set];
478         buf[1] = '\n';
479
480         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
481
482         return ret;
483 }
484
485 static ssize_t
486 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
487                     loff_t *ppos)
488 {
489         const char *system = filp->private_data;
490         unsigned long val;
491         char buf[64];
492         ssize_t ret;
493
494         if (cnt >= sizeof(buf))
495                 return -EINVAL;
496
497         if (copy_from_user(&buf, ubuf, cnt))
498                 return -EFAULT;
499
500         buf[cnt] = 0;
501
502         ret = strict_strtoul(buf, 10, &val);
503         if (ret < 0)
504                 return ret;
505
506         ret = tracing_update_buffers();
507         if (ret < 0)
508                 return ret;
509
510         if (val != 0 && val != 1)
511                 return -EINVAL;
512
513         ret = __ftrace_set_clr_event(NULL, system, NULL, val);
514         if (ret)
515                 goto out;
516
517         ret = cnt;
518
519 out:
520         *ppos += cnt;
521
522         return ret;
523 }
524
525 extern char *__bad_type_size(void);
526
527 #undef FIELD
528 #define FIELD(type, name)                                               \
529         sizeof(type) != sizeof(field.name) ? __bad_type_size() :        \
530         #type, "common_" #name, offsetof(typeof(field), name),          \
531                 sizeof(field.name)
532
533 static int trace_write_header(struct trace_seq *s)
534 {
535         struct trace_entry field;
536
537         /* struct trace_entry */
538         return trace_seq_printf(s,
539                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
540                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
541                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
542                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
543                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
544                                 "\n",
545                                 FIELD(unsigned short, type),
546                                 FIELD(unsigned char, flags),
547                                 FIELD(unsigned char, preempt_count),
548                                 FIELD(int, pid),
549                                 FIELD(int, tgid));
550 }
551
552 static ssize_t
553 event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
554                   loff_t *ppos)
555 {
556         struct ftrace_event_call *call = filp->private_data;
557         struct trace_seq *s;
558         char *buf;
559         int r;
560
561         if (*ppos)
562                 return 0;
563
564         s = kmalloc(sizeof(*s), GFP_KERNEL);
565         if (!s)
566                 return -ENOMEM;
567
568         trace_seq_init(s);
569
570         /* If any of the first writes fail, so will the show_format. */
571
572         trace_seq_printf(s, "name: %s\n", call->name);
573         trace_seq_printf(s, "ID: %d\n", call->id);
574         trace_seq_printf(s, "format:\n");
575         trace_write_header(s);
576
577         r = call->show_format(s);
578         if (!r) {
579                 /*
580                  * ug!  The format output is bigger than a PAGE!!
581                  */
582                 buf = "FORMAT TOO BIG\n";
583                 r = simple_read_from_buffer(ubuf, cnt, ppos,
584                                               buf, strlen(buf));
585                 goto out;
586         }
587
588         r = simple_read_from_buffer(ubuf, cnt, ppos,
589                                     s->buffer, s->len);
590  out:
591         kfree(s);
592         return r;
593 }
594
595 static ssize_t
596 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
597 {
598         struct ftrace_event_call *call = filp->private_data;
599         struct trace_seq *s;
600         int r;
601
602         if (*ppos)
603                 return 0;
604
605         s = kmalloc(sizeof(*s), GFP_KERNEL);
606         if (!s)
607                 return -ENOMEM;
608
609         trace_seq_init(s);
610         trace_seq_printf(s, "%d\n", call->id);
611
612         r = simple_read_from_buffer(ubuf, cnt, ppos,
613                                     s->buffer, s->len);
614         kfree(s);
615         return r;
616 }
617
618 static ssize_t
619 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
620                   loff_t *ppos)
621 {
622         struct ftrace_event_call *call = filp->private_data;
623         struct trace_seq *s;
624         int r;
625
626         if (*ppos)
627                 return 0;
628
629         s = kmalloc(sizeof(*s), GFP_KERNEL);
630         if (!s)
631                 return -ENOMEM;
632
633         trace_seq_init(s);
634
635         print_event_filter(call, s);
636         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
637
638         kfree(s);
639
640         return r;
641 }
642
643 static ssize_t
644 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
645                    loff_t *ppos)
646 {
647         struct ftrace_event_call *call = filp->private_data;
648         char *buf;
649         int err;
650
651         if (cnt >= PAGE_SIZE)
652                 return -EINVAL;
653
654         buf = (char *)__get_free_page(GFP_TEMPORARY);
655         if (!buf)
656                 return -ENOMEM;
657
658         if (copy_from_user(buf, ubuf, cnt)) {
659                 free_page((unsigned long) buf);
660                 return -EFAULT;
661         }
662         buf[cnt] = '\0';
663
664         err = apply_event_filter(call, buf);
665         free_page((unsigned long) buf);
666         if (err < 0)
667                 return err;
668
669         *ppos += cnt;
670
671         return cnt;
672 }
673
674 static ssize_t
675 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
676                       loff_t *ppos)
677 {
678         struct event_subsystem *system = filp->private_data;
679         struct trace_seq *s;
680         int r;
681
682         if (*ppos)
683                 return 0;
684
685         s = kmalloc(sizeof(*s), GFP_KERNEL);
686         if (!s)
687                 return -ENOMEM;
688
689         trace_seq_init(s);
690
691         print_subsystem_event_filter(system, s);
692         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
693
694         kfree(s);
695
696         return r;
697 }
698
699 static ssize_t
700 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
701                        loff_t *ppos)
702 {
703         struct event_subsystem *system = filp->private_data;
704         char *buf;
705         int err;
706
707         if (cnt >= PAGE_SIZE)
708                 return -EINVAL;
709
710         buf = (char *)__get_free_page(GFP_TEMPORARY);
711         if (!buf)
712                 return -ENOMEM;
713
714         if (copy_from_user(buf, ubuf, cnt)) {
715                 free_page((unsigned long) buf);
716                 return -EFAULT;
717         }
718         buf[cnt] = '\0';
719
720         err = apply_subsystem_event_filter(system, buf);
721         free_page((unsigned long) buf);
722         if (err < 0)
723                 return err;
724
725         *ppos += cnt;
726
727         return cnt;
728 }
729
730 static ssize_t
731 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
732 {
733         int (*func)(struct trace_seq *s) = filp->private_data;
734         struct trace_seq *s;
735         int r;
736
737         if (*ppos)
738                 return 0;
739
740         s = kmalloc(sizeof(*s), GFP_KERNEL);
741         if (!s)
742                 return -ENOMEM;
743
744         trace_seq_init(s);
745
746         func(s);
747         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
748
749         kfree(s);
750
751         return r;
752 }
753
754 static const struct seq_operations show_event_seq_ops = {
755         .start = t_start,
756         .next = t_next,
757         .show = t_show,
758         .stop = t_stop,
759 };
760
761 static const struct seq_operations show_set_event_seq_ops = {
762         .start = s_start,
763         .next = s_next,
764         .show = t_show,
765         .stop = t_stop,
766 };
767
768 static const struct file_operations ftrace_avail_fops = {
769         .open = ftrace_event_seq_open,
770         .read = seq_read,
771         .llseek = seq_lseek,
772         .release = seq_release,
773 };
774
775 static const struct file_operations ftrace_set_event_fops = {
776         .open = ftrace_event_seq_open,
777         .read = seq_read,
778         .write = ftrace_event_write,
779         .llseek = seq_lseek,
780         .release = seq_release,
781 };
782
783 static const struct file_operations ftrace_enable_fops = {
784         .open = tracing_open_generic,
785         .read = event_enable_read,
786         .write = event_enable_write,
787 };
788
789 static const struct file_operations ftrace_event_format_fops = {
790         .open = tracing_open_generic,
791         .read = event_format_read,
792 };
793
794 static const struct file_operations ftrace_event_id_fops = {
795         .open = tracing_open_generic,
796         .read = event_id_read,
797 };
798
799 static const struct file_operations ftrace_event_filter_fops = {
800         .open = tracing_open_generic,
801         .read = event_filter_read,
802         .write = event_filter_write,
803 };
804
805 static const struct file_operations ftrace_subsystem_filter_fops = {
806         .open = tracing_open_generic,
807         .read = subsystem_filter_read,
808         .write = subsystem_filter_write,
809 };
810
811 static const struct file_operations ftrace_system_enable_fops = {
812         .open = tracing_open_generic,
813         .read = system_enable_read,
814         .write = system_enable_write,
815 };
816
817 static const struct file_operations ftrace_show_header_fops = {
818         .open = tracing_open_generic,
819         .read = show_header,
820 };
821
822 static struct dentry *event_trace_events_dir(void)
823 {
824         static struct dentry *d_tracer;
825         static struct dentry *d_events;
826
827         if (d_events)
828                 return d_events;
829
830         d_tracer = tracing_init_dentry();
831         if (!d_tracer)
832                 return NULL;
833
834         d_events = debugfs_create_dir("events", d_tracer);
835         if (!d_events)
836                 pr_warning("Could not create debugfs "
837                            "'events' directory\n");
838
839         return d_events;
840 }
841
842 static LIST_HEAD(event_subsystems);
843
844 static struct dentry *
845 event_subsystem_dir(const char *name, struct dentry *d_events)
846 {
847         struct event_subsystem *system;
848         struct dentry *entry;
849
850         /* First see if we did not already create this dir */
851         list_for_each_entry(system, &event_subsystems, list) {
852                 if (strcmp(system->name, name) == 0)
853                         return system->entry;
854         }
855
856         /* need to create new entry */
857         system = kmalloc(sizeof(*system), GFP_KERNEL);
858         if (!system) {
859                 pr_warning("No memory to create event subsystem %s\n",
860                            name);
861                 return d_events;
862         }
863
864         system->entry = debugfs_create_dir(name, d_events);
865         if (!system->entry) {
866                 pr_warning("Could not create event subsystem %s\n",
867                            name);
868                 kfree(system);
869                 return d_events;
870         }
871
872         system->name = kstrdup(name, GFP_KERNEL);
873         if (!system->name) {
874                 debugfs_remove(system->entry);
875                 kfree(system);
876                 return d_events;
877         }
878
879         list_add(&system->list, &event_subsystems);
880
881         system->filter = NULL;
882
883         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
884         if (!system->filter) {
885                 pr_warning("Could not allocate filter for subsystem "
886                            "'%s'\n", name);
887                 return system->entry;
888         }
889
890         entry = debugfs_create_file("filter", 0644, system->entry, system,
891                                     &ftrace_subsystem_filter_fops);
892         if (!entry) {
893                 kfree(system->filter);
894                 system->filter = NULL;
895                 pr_warning("Could not create debugfs "
896                            "'%s/filter' entry\n", name);
897         }
898
899         entry = trace_create_file("enable", 0644, system->entry,
900                                   (void *)system->name,
901                                   &ftrace_system_enable_fops);
902
903         return system->entry;
904 }
905
906 static int
907 event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
908                  const struct file_operations *id,
909                  const struct file_operations *enable,
910                  const struct file_operations *filter,
911                  const struct file_operations *format)
912 {
913         struct dentry *entry;
914         int ret;
915
916         /*
917          * If the trace point header did not define TRACE_SYSTEM
918          * then the system would be called "TRACE_SYSTEM".
919          */
920         if (strcmp(call->system, TRACE_SYSTEM) != 0)
921                 d_events = event_subsystem_dir(call->system, d_events);
922
923         if (call->raw_init) {
924                 ret = call->raw_init();
925                 if (ret < 0) {
926                         pr_warning("Could not initialize trace point"
927                                    " events/%s\n", call->name);
928                         return ret;
929                 }
930         }
931
932         call->dir = debugfs_create_dir(call->name, d_events);
933         if (!call->dir) {
934                 pr_warning("Could not create debugfs "
935                            "'%s' directory\n", call->name);
936                 return -1;
937         }
938
939         if (call->regfunc)
940                 entry = trace_create_file("enable", 0644, call->dir, call,
941                                           enable);
942
943         if (call->id)
944                 entry = trace_create_file("id", 0444, call->dir, call,
945                                           id);
946
947         if (call->define_fields) {
948                 ret = call->define_fields();
949                 if (ret < 0) {
950                         pr_warning("Could not initialize trace point"
951                                    " events/%s\n", call->name);
952                         return ret;
953                 }
954                 entry = trace_create_file("filter", 0644, call->dir, call,
955                                           filter);
956         }
957
958         /* A trace may not want to export its format */
959         if (!call->show_format)
960                 return 0;
961
962         entry = trace_create_file("format", 0444, call->dir, call,
963                                   format);
964
965         return 0;
966 }
967
968 #define for_each_event(event, start, end)                       \
969         for (event = start;                                     \
970              (unsigned long)event < (unsigned long)end;         \
971              event++)
972
973 #ifdef CONFIG_MODULES
974
975 static LIST_HEAD(ftrace_module_file_list);
976
977 /*
978  * Modules must own their file_operations to keep up with
979  * reference counting.
980  */
981 struct ftrace_module_file_ops {
982         struct list_head                list;
983         struct module                   *mod;
984         struct file_operations          id;
985         struct file_operations          enable;
986         struct file_operations          format;
987         struct file_operations          filter;
988 };
989
990 static struct ftrace_module_file_ops *
991 trace_create_file_ops(struct module *mod)
992 {
993         struct ftrace_module_file_ops *file_ops;
994
995         /*
996          * This is a bit of a PITA. To allow for correct reference
997          * counting, modules must "own" their file_operations.
998          * To do this, we allocate the file operations that will be
999          * used in the event directory.
1000          */
1001
1002         file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1003         if (!file_ops)
1004                 return NULL;
1005
1006         file_ops->mod = mod;
1007
1008         file_ops->id = ftrace_event_id_fops;
1009         file_ops->id.owner = mod;
1010
1011         file_ops->enable = ftrace_enable_fops;
1012         file_ops->enable.owner = mod;
1013
1014         file_ops->filter = ftrace_event_filter_fops;
1015         file_ops->filter.owner = mod;
1016
1017         file_ops->format = ftrace_event_format_fops;
1018         file_ops->format.owner = mod;
1019
1020         list_add(&file_ops->list, &ftrace_module_file_list);
1021
1022         return file_ops;
1023 }
1024
1025 static void trace_module_add_events(struct module *mod)
1026 {
1027         struct ftrace_module_file_ops *file_ops = NULL;
1028         struct ftrace_event_call *call, *start, *end;
1029         struct dentry *d_events;
1030
1031         start = mod->trace_events;
1032         end = mod->trace_events + mod->num_trace_events;
1033
1034         if (start == end)
1035                 return;
1036
1037         d_events = event_trace_events_dir();
1038         if (!d_events)
1039                 return;
1040
1041         for_each_event(call, start, end) {
1042                 /* The linker may leave blanks */
1043                 if (!call->name)
1044                         continue;
1045
1046                 /*
1047                  * This module has events, create file ops for this module
1048                  * if not already done.
1049                  */
1050                 if (!file_ops) {
1051                         file_ops = trace_create_file_ops(mod);
1052                         if (!file_ops)
1053                                 return;
1054                 }
1055                 call->mod = mod;
1056                 list_add(&call->list, &ftrace_events);
1057                 event_create_dir(call, d_events,
1058                                  &file_ops->id, &file_ops->enable,
1059                                  &file_ops->filter, &file_ops->format);
1060         }
1061 }
1062
1063 static void trace_module_remove_events(struct module *mod)
1064 {
1065         struct ftrace_module_file_ops *file_ops;
1066         struct ftrace_event_call *call, *p;
1067         bool found = false;
1068
1069         down_write(&trace_event_mutex);
1070         list_for_each_entry_safe(call, p, &ftrace_events, list) {
1071                 if (call->mod == mod) {
1072                         found = true;
1073                         ftrace_event_enable_disable(call, 0);
1074                         if (call->event)
1075                                 __unregister_ftrace_event(call->event);
1076                         debugfs_remove_recursive(call->dir);
1077                         list_del(&call->list);
1078                         trace_destroy_fields(call);
1079                         destroy_preds(call);
1080                 }
1081         }
1082
1083         /* Now free the file_operations */
1084         list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1085                 if (file_ops->mod == mod)
1086                         break;
1087         }
1088         if (&file_ops->list != &ftrace_module_file_list) {
1089                 list_del(&file_ops->list);
1090                 kfree(file_ops);
1091         }
1092
1093         /*
1094          * It is safest to reset the ring buffer if the module being unloaded
1095          * registered any events.
1096          */
1097         if (found)
1098                 tracing_reset_current_online_cpus();
1099         up_write(&trace_event_mutex);
1100 }
1101
1102 static int trace_module_notify(struct notifier_block *self,
1103                                unsigned long val, void *data)
1104 {
1105         struct module *mod = data;
1106
1107         mutex_lock(&event_mutex);
1108         switch (val) {
1109         case MODULE_STATE_COMING:
1110                 trace_module_add_events(mod);
1111                 break;
1112         case MODULE_STATE_GOING:
1113                 trace_module_remove_events(mod);
1114                 break;
1115         }
1116         mutex_unlock(&event_mutex);
1117
1118         return 0;
1119 }
1120 #else
1121 static int trace_module_notify(struct notifier_block *self,
1122                                unsigned long val, void *data)
1123 {
1124         return 0;
1125 }
1126 #endif /* CONFIG_MODULES */
1127
1128 struct notifier_block trace_module_nb = {
1129         .notifier_call = trace_module_notify,
1130         .priority = 0,
1131 };
1132
1133 extern struct ftrace_event_call __start_ftrace_events[];
1134 extern struct ftrace_event_call __stop_ftrace_events[];
1135
1136 static __init int event_trace_init(void)
1137 {
1138         struct ftrace_event_call *call;
1139         struct dentry *d_tracer;
1140         struct dentry *entry;
1141         struct dentry *d_events;
1142         int ret;
1143
1144         d_tracer = tracing_init_dentry();
1145         if (!d_tracer)
1146                 return 0;
1147
1148         entry = debugfs_create_file("available_events", 0444, d_tracer,
1149                                     (void *)&show_event_seq_ops,
1150                                     &ftrace_avail_fops);
1151         if (!entry)
1152                 pr_warning("Could not create debugfs "
1153                            "'available_events' entry\n");
1154
1155         entry = debugfs_create_file("set_event", 0644, d_tracer,
1156                                     (void *)&show_set_event_seq_ops,
1157                                     &ftrace_set_event_fops);
1158         if (!entry)
1159                 pr_warning("Could not create debugfs "
1160                            "'set_event' entry\n");
1161
1162         d_events = event_trace_events_dir();
1163         if (!d_events)
1164                 return 0;
1165
1166         /* ring buffer internal formats */
1167         trace_create_file("header_page", 0444, d_events,
1168                           ring_buffer_print_page_header,
1169                           &ftrace_show_header_fops);
1170
1171         trace_create_file("header_event", 0444, d_events,
1172                           ring_buffer_print_entry_header,
1173                           &ftrace_show_header_fops);
1174
1175         trace_create_file("enable", 0644, d_events,
1176                           NULL, &ftrace_system_enable_fops);
1177
1178         for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
1179                 /* The linker may leave blanks */
1180                 if (!call->name)
1181                         continue;
1182                 list_add(&call->list, &ftrace_events);
1183                 event_create_dir(call, d_events, &ftrace_event_id_fops,
1184                                  &ftrace_enable_fops, &ftrace_event_filter_fops,
1185                                  &ftrace_event_format_fops);
1186         }
1187
1188         ret = register_module_notifier(&trace_module_nb);
1189         if (ret)
1190                 pr_warning("Failed to register trace events module notifier\n");
1191
1192         return 0;
1193 }
1194 fs_initcall(event_trace_init);
1195
1196 #ifdef CONFIG_FTRACE_STARTUP_TEST
1197
1198 static DEFINE_SPINLOCK(test_spinlock);
1199 static DEFINE_SPINLOCK(test_spinlock_irq);
1200 static DEFINE_MUTEX(test_mutex);
1201
1202 static __init void test_work(struct work_struct *dummy)
1203 {
1204         spin_lock(&test_spinlock);
1205         spin_lock_irq(&test_spinlock_irq);
1206         udelay(1);
1207         spin_unlock_irq(&test_spinlock_irq);
1208         spin_unlock(&test_spinlock);
1209
1210         mutex_lock(&test_mutex);
1211         msleep(1);
1212         mutex_unlock(&test_mutex);
1213 }
1214
1215 static __init int event_test_thread(void *unused)
1216 {
1217         void *test_malloc;
1218
1219         test_malloc = kmalloc(1234, GFP_KERNEL);
1220         if (!test_malloc)
1221                 pr_info("failed to kmalloc\n");
1222
1223         schedule_on_each_cpu(test_work);
1224
1225         kfree(test_malloc);
1226
1227         set_current_state(TASK_INTERRUPTIBLE);
1228         while (!kthread_should_stop())
1229                 schedule();
1230
1231         return 0;
1232 }
1233
1234 /*
1235  * Do various things that may trigger events.
1236  */
1237 static __init void event_test_stuff(void)
1238 {
1239         struct task_struct *test_thread;
1240
1241         test_thread = kthread_run(event_test_thread, NULL, "test-events");
1242         msleep(1);
1243         kthread_stop(test_thread);
1244 }
1245
1246 /*
1247  * For every trace event defined, we will test each trace point separately,
1248  * and then by groups, and finally all trace points.
1249  */
1250 static __init void event_trace_self_tests(void)
1251 {
1252         struct ftrace_event_call *call;
1253         struct event_subsystem *system;
1254         int ret;
1255
1256         pr_info("Running tests on trace events:\n");
1257
1258         list_for_each_entry(call, &ftrace_events, list) {
1259
1260                 /* Only test those that have a regfunc */
1261                 if (!call->regfunc)
1262                         continue;
1263
1264                 pr_info("Testing event %s: ", call->name);
1265
1266                 /*
1267                  * If an event is already enabled, someone is using
1268                  * it and the self test should not be on.
1269                  */
1270                 if (call->enabled) {
1271                         pr_warning("Enabled event during self test!\n");
1272                         WARN_ON_ONCE(1);
1273                         continue;
1274                 }
1275
1276                 ftrace_event_enable_disable(call, 1);
1277                 event_test_stuff();
1278                 ftrace_event_enable_disable(call, 0);
1279
1280                 pr_cont("OK\n");
1281         }
1282
1283         /* Now test at the sub system level */
1284
1285         pr_info("Running tests on trace event systems:\n");
1286
1287         list_for_each_entry(system, &event_subsystems, list) {
1288
1289                 /* the ftrace system is special, skip it */
1290                 if (strcmp(system->name, "ftrace") == 0)
1291                         continue;
1292
1293                 pr_info("Testing event system %s: ", system->name);
1294
1295                 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
1296                 if (WARN_ON_ONCE(ret)) {
1297                         pr_warning("error enabling system %s\n",
1298                                    system->name);
1299                         continue;
1300                 }
1301
1302                 event_test_stuff();
1303
1304                 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
1305                 if (WARN_ON_ONCE(ret))
1306                         pr_warning("error disabling system %s\n",
1307                                    system->name);
1308
1309                 pr_cont("OK\n");
1310         }
1311
1312         /* Test with all events enabled */
1313
1314         pr_info("Running tests on all trace events:\n");
1315         pr_info("Testing all events: ");
1316
1317         ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
1318         if (WARN_ON_ONCE(ret)) {
1319                 pr_warning("error enabling all events\n");
1320                 return;
1321         }
1322
1323         event_test_stuff();
1324
1325         /* reset sysname */
1326         ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
1327         if (WARN_ON_ONCE(ret)) {
1328                 pr_warning("error disabling all events\n");
1329                 return;
1330         }
1331
1332         pr_cont("OK\n");
1333 }
1334
1335 #ifdef CONFIG_FUNCTION_TRACER
1336
1337 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
1338
1339 static void
1340 function_test_events_call(unsigned long ip, unsigned long parent_ip)
1341 {
1342         struct ring_buffer_event *event;
1343         struct ftrace_entry *entry;
1344         unsigned long flags;
1345         long disabled;
1346         int resched;
1347         int cpu;
1348         int pc;
1349
1350         pc = preempt_count();
1351         resched = ftrace_preempt_disable();
1352         cpu = raw_smp_processor_id();
1353         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
1354
1355         if (disabled != 1)
1356                 goto out;
1357
1358         local_save_flags(flags);
1359
1360         event = trace_current_buffer_lock_reserve(TRACE_FN, sizeof(*entry),
1361                                                   flags, pc);
1362         if (!event)
1363                 goto out;
1364         entry   = ring_buffer_event_data(event);
1365         entry->ip                       = ip;
1366         entry->parent_ip                = parent_ip;
1367
1368         trace_nowake_buffer_unlock_commit(event, flags, pc);
1369
1370  out:
1371         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
1372         ftrace_preempt_enable(resched);
1373 }
1374
1375 static struct ftrace_ops trace_ops __initdata  =
1376 {
1377         .func = function_test_events_call,
1378 };
1379
1380 static __init void event_trace_self_test_with_function(void)
1381 {
1382         register_ftrace_function(&trace_ops);
1383         pr_info("Running tests again, along with the function tracer\n");
1384         event_trace_self_tests();
1385         unregister_ftrace_function(&trace_ops);
1386 }
1387 #else
1388 static __init void event_trace_self_test_with_function(void)
1389 {
1390 }
1391 #endif
1392
1393 static __init int event_trace_self_tests_init(void)
1394 {
1395
1396         event_trace_self_tests();
1397
1398         event_trace_self_test_with_function();
1399
1400         return 0;
1401 }
1402
1403 late_initcall(event_trace_self_tests_init);
1404
1405 #endif