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