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