]> git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - kernel/trace/trace_events.c
projects / mirror_ubuntu-bionic-kernel.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
tracing: Change event_enable/disable_read() to verify i_private != NULL
[mirror_ubuntu-bionic-kernel.git] / kernel / trace / trace_events.c
1 /*
2 * event tracer
3 *
4 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
5 *
6 * - Added format output of fields of the trace point.
7 * This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
8 *
9 */
10
11 #include <linux/workqueue.h>
12 #include <linux/spinlock.h>
13 #include <linux/kthread.h>
14 #include <linux/debugfs.h>
15 #include <linux/uaccess.h>
16 #include <linux/module.h>
17 #include <linux/ctype.h>
18 #include <linux/slab.h>
19 #include <linux/delay.h>
20
21 #include <asm/setup.h>
22
23 #include "trace_output.h"
24
25 #undef TRACE_SYSTEM
26 #define TRACE_SYSTEM "TRACE_SYSTEM"
27
28 DEFINE_MUTEX(event_mutex);
29
30 DEFINE_MUTEX(event_storage_mutex);
31 EXPORT_SYMBOL_GPL(event_storage_mutex);
32
33 char event_storage[EVENT_STORAGE_SIZE];
34 EXPORT_SYMBOL_GPL(event_storage);
35
36 LIST_HEAD(ftrace_events);
37 static LIST_HEAD(ftrace_common_fields);
38
39 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
40
41 static struct kmem_cache *field_cachep;
42 static struct kmem_cache *file_cachep;
43
44 #define SYSTEM_FL_FREE_NAME (1 << 31)
45
46 static inline int system_refcount(struct event_subsystem *system)
47 {
48 return system->ref_count & ~SYSTEM_FL_FREE_NAME;
49 }
50
51 static int system_refcount_inc(struct event_subsystem *system)
52 {
53 return (system->ref_count++) & ~SYSTEM_FL_FREE_NAME;
54 }
55
56 static int system_refcount_dec(struct event_subsystem *system)
57 {
58 return (--system->ref_count) & ~SYSTEM_FL_FREE_NAME;
59 }
60
61 /* Double loops, do not use break, only goto's work */
62 #define do_for_each_event_file(tr, file) \
63 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
64 list_for_each_entry(file, &tr->events, list)
65
66 #define do_for_each_event_file_safe(tr, file) \
67 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
68 struct ftrace_event_file *___n; \
69 list_for_each_entry_safe(file, ___n, &tr->events, list)
70
71 #define while_for_each_event_file() \
72 }
73
74 static struct list_head *
75 trace_get_fields(struct ftrace_event_call *event_call)
76 {
77 if (!event_call->class->get_fields)
78 return &event_call->class->fields;
79 return event_call->class->get_fields(event_call);
80 }
81
82 static struct ftrace_event_field *
83 __find_event_field(struct list_head *head, char *name)
84 {
85 struct ftrace_event_field *field;
86
87 list_for_each_entry(field, head, link) {
88 if (!strcmp(field->name, name))
89 return field;
90 }
91
92 return NULL;
93 }
94
95 struct ftrace_event_field *
96 trace_find_event_field(struct ftrace_event_call *call, char *name)
97 {
98 struct ftrace_event_field *field;
99 struct list_head *head;
100
101 field = __find_event_field(&ftrace_common_fields, name);
102 if (field)
103 return field;
104
105 head = trace_get_fields(call);
106 return __find_event_field(head, name);
107 }
108
109 static int __trace_define_field(struct list_head *head, const char *type,
110 const char *name, int offset, int size,
111 int is_signed, int filter_type)
112 {
113 struct ftrace_event_field *field;
114
115 field = kmem_cache_alloc(field_cachep, GFP_TRACE);
116 if (!field)
117 return -ENOMEM;
118
119 field->name = name;
120 field->type = type;
121
122 if (filter_type == FILTER_OTHER)
123 field->filter_type = filter_assign_type(type);
124 else
125 field->filter_type = filter_type;
126
127 field->offset = offset;
128 field->size = size;
129 field->is_signed = is_signed;
130
131 list_add(&field->link, head);
132
133 return 0;
134 }
135
136 int trace_define_field(struct ftrace_event_call *call, const char *type,
137 const char *name, int offset, int size, int is_signed,
138 int filter_type)
139 {
140 struct list_head *head;
141
142 if (WARN_ON(!call->class))
143 return 0;
144
145 head = trace_get_fields(call);
146 return __trace_define_field(head, type, name, offset, size,
147 is_signed, filter_type);
148 }
149 EXPORT_SYMBOL_GPL(trace_define_field);
150
151 #define __common_field(type, item) \
152 ret = __trace_define_field(&ftrace_common_fields, #type, \
153 "common_" #item, \
154 offsetof(typeof(ent), item), \
155 sizeof(ent.item), \
156 is_signed_type(type), FILTER_OTHER); \
157 if (ret) \
158 return ret;
159
160 static int trace_define_common_fields(void)
161 {
162 int ret;
163 struct trace_entry ent;
164
165 __common_field(unsigned short, type);
166 __common_field(unsigned char, flags);
167 __common_field(unsigned char, preempt_count);
168 __common_field(int, pid);
169
170 return ret;
171 }
172
173 static void trace_destroy_fields(struct ftrace_event_call *call)
174 {
175 struct ftrace_event_field *field, *next;
176 struct list_head *head;
177
178 head = trace_get_fields(call);
179 list_for_each_entry_safe(field, next, head, link) {
180 list_del(&field->link);
181 kmem_cache_free(field_cachep, field);
182 }
183 }
184
185 int trace_event_raw_init(struct ftrace_event_call *call)
186 {
187 int id;
188
189 id = register_ftrace_event(&call->event);
190 if (!id)
191 return -ENODEV;
192
193 return 0;
194 }
195 EXPORT_SYMBOL_GPL(trace_event_raw_init);
196
197 int ftrace_event_reg(struct ftrace_event_call *call,
198 enum trace_reg type, void *data)
199 {
200 struct ftrace_event_file *file = data;
201
202 switch (type) {
203 case TRACE_REG_REGISTER:
204 return tracepoint_probe_register(call->name,
205 call->class->probe,
206 file);
207 case TRACE_REG_UNREGISTER:
208 tracepoint_probe_unregister(call->name,
209 call->class->probe,
210 file);
211 return 0;
212
213 #ifdef CONFIG_PERF_EVENTS
214 case TRACE_REG_PERF_REGISTER:
215 return tracepoint_probe_register(call->name,
216 call->class->perf_probe,
217 call);
218 case TRACE_REG_PERF_UNREGISTER:
219 tracepoint_probe_unregister(call->name,
220 call->class->perf_probe,
221 call);
222 return 0;
223 case TRACE_REG_PERF_OPEN:
224 case TRACE_REG_PERF_CLOSE:
225 case TRACE_REG_PERF_ADD:
226 case TRACE_REG_PERF_DEL:
227 return 0;
228 #endif
229 }
230 return 0;
231 }
232 EXPORT_SYMBOL_GPL(ftrace_event_reg);
233
234 void trace_event_enable_cmd_record(bool enable)
235 {
236 struct ftrace_event_file *file;
237 struct trace_array *tr;
238
239 mutex_lock(&event_mutex);
240 do_for_each_event_file(tr, file) {
241
242 if (!(file->flags & FTRACE_EVENT_FL_ENABLED))
243 continue;
244
245 if (enable) {
246 tracing_start_cmdline_record();
247 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
248 } else {
249 tracing_stop_cmdline_record();
250 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
251 }
252 } while_for_each_event_file();
253 mutex_unlock(&event_mutex);
254 }
255
256 static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
257 int enable, int soft_disable)
258 {
259 struct ftrace_event_call *call = file->event_call;
260 int ret = 0;
261 int disable;
262
263 switch (enable) {
264 case 0:
265 /*
266 * When soft_disable is set and enable is cleared, the sm_ref
267 * reference counter is decremented. If it reaches 0, we want
268 * to clear the SOFT_DISABLED flag but leave the event in the
269 * state that it was. That is, if the event was enabled and
270 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
271 * is set we do not want the event to be enabled before we
272 * clear the bit.
273 *
274 * When soft_disable is not set but the SOFT_MODE flag is,
275 * we do nothing. Do not disable the tracepoint, otherwise
276 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
277 */
278 if (soft_disable) {
279 if (atomic_dec_return(&file->sm_ref) > 0)
280 break;
281 disable = file->flags & FTRACE_EVENT_FL_SOFT_DISABLED;
282 clear_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
283 } else
284 disable = !(file->flags & FTRACE_EVENT_FL_SOFT_MODE);
285
286 if (disable && (file->flags & FTRACE_EVENT_FL_ENABLED)) {
287 clear_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
288 if (file->flags & FTRACE_EVENT_FL_RECORDED_CMD) {
289 tracing_stop_cmdline_record();
290 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
291 }
292 call->class->reg(call, TRACE_REG_UNREGISTER, file);
293 }
294 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
295 if (file->flags & FTRACE_EVENT_FL_SOFT_MODE)
296 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
297 else
298 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
299 break;
300 case 1:
301 /*
302 * When soft_disable is set and enable is set, we want to
303 * register the tracepoint for the event, but leave the event
304 * as is. That means, if the event was already enabled, we do
305 * nothing (but set SOFT_MODE). If the event is disabled, we
306 * set SOFT_DISABLED before enabling the event tracepoint, so
307 * it still seems to be disabled.
308 */
309 if (!soft_disable)
310 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
311 else {
312 if (atomic_inc_return(&file->sm_ref) > 1)
313 break;
314 set_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
315 }
316
317 if (!(file->flags & FTRACE_EVENT_FL_ENABLED)) {
318
319 /* Keep the event disabled, when going to SOFT_MODE. */
320 if (soft_disable)
321 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
322
323 if (trace_flags & TRACE_ITER_RECORD_CMD) {
324 tracing_start_cmdline_record();
325 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
326 }
327 ret = call->class->reg(call, TRACE_REG_REGISTER, file);
328 if (ret) {
329 tracing_stop_cmdline_record();
330 pr_info("event trace: Could not enable event "
331 "%s\n", call->name);
332 break;
333 }
334 set_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
335
336 /* WAS_ENABLED gets set but never cleared. */
337 call->flags |= TRACE_EVENT_FL_WAS_ENABLED;
338 }
339 break;
340 }
341
342 return ret;
343 }
344
345 static int ftrace_event_enable_disable(struct ftrace_event_file *file,
346 int enable)
347 {
348 return __ftrace_event_enable_disable(file, enable, 0);
349 }
350
351 static void ftrace_clear_events(struct trace_array *tr)
352 {
353 struct ftrace_event_file *file;
354
355 mutex_lock(&event_mutex);
356 list_for_each_entry(file, &tr->events, list) {
357 ftrace_event_enable_disable(file, 0);
358 }
359 mutex_unlock(&event_mutex);
360 }
361
362 static void __put_system(struct event_subsystem *system)
363 {
364 struct event_filter *filter = system->filter;
365
366 WARN_ON_ONCE(system_refcount(system) == 0);
367 if (system_refcount_dec(system))
368 return;
369
370 list_del(&system->list);
371
372 if (filter) {
373 kfree(filter->filter_string);
374 kfree(filter);
375 }
376 if (system->ref_count & SYSTEM_FL_FREE_NAME)
377 kfree(system->name);
378 kfree(system);
379 }
380
381 static void __get_system(struct event_subsystem *system)
382 {
383 WARN_ON_ONCE(system_refcount(system) == 0);
384 system_refcount_inc(system);
385 }
386
387 static void __get_system_dir(struct ftrace_subsystem_dir *dir)
388 {
389 WARN_ON_ONCE(dir->ref_count == 0);
390 dir->ref_count++;
391 __get_system(dir->subsystem);
392 }
393
394 static void __put_system_dir(struct ftrace_subsystem_dir *dir)
395 {
396 WARN_ON_ONCE(dir->ref_count == 0);
397 /* If the subsystem is about to be freed, the dir must be too */
398 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
399
400 __put_system(dir->subsystem);
401 if (!--dir->ref_count)
402 kfree(dir);
403 }
404
405 static void put_system(struct ftrace_subsystem_dir *dir)
406 {
407 mutex_lock(&event_mutex);
408 __put_system_dir(dir);
409 mutex_unlock(&event_mutex);
410 }
411
412 static void *event_file_data(struct file *filp)
413 {
414 return ACCESS_ONCE(file_inode(filp)->i_private);
415 }
416
417 /*
418 * Open and update trace_array ref count.
419 * Must have the current trace_array passed to it.
420 */
421 static int tracing_open_generic_file(struct inode *inode, struct file *filp)
422 {
423 struct ftrace_event_file *file = inode->i_private;
424 struct trace_array *tr = file->tr;
425 int ret;
426
427 if (trace_array_get(tr) < 0)
428 return -ENODEV;
429
430 ret = tracing_open_generic(inode, filp);
431 if (ret < 0)
432 trace_array_put(tr);
433 return ret;
434 }
435
436 static int tracing_release_generic_file(struct inode *inode, struct file *filp)
437 {
438 struct ftrace_event_file *file = inode->i_private;
439 struct trace_array *tr = file->tr;
440
441 trace_array_put(tr);
442
443 return 0;
444 }
445
446 /*
447 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
448 */
449 static int
450 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
451 const char *sub, const char *event, int set)
452 {
453 struct ftrace_event_file *file;
454 struct ftrace_event_call *call;
455 int ret = -EINVAL;
456
457 list_for_each_entry(file, &tr->events, list) {
458
459 call = file->event_call;
460
461 if (!call->name || !call->class || !call->class->reg)
462 continue;
463
464 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
465 continue;
466
467 if (match &&
468 strcmp(match, call->name) != 0 &&
469 strcmp(match, call->class->system) != 0)
470 continue;
471
472 if (sub && strcmp(sub, call->class->system) != 0)
473 continue;
474
475 if (event && strcmp(event, call->name) != 0)
476 continue;
477
478 ftrace_event_enable_disable(file, set);
479
480 ret = 0;
481 }
482
483 return ret;
484 }
485
486 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
487 const char *sub, const char *event, int set)
488 {
489 int ret;
490
491 mutex_lock(&event_mutex);
492 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
493 mutex_unlock(&event_mutex);
494
495 return ret;
496 }
497
498 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
499 {
500 char *event = NULL, *sub = NULL, *match;
501
502 /*
503 * The buf format can be <subsystem>:<event-name>
504 * *:<event-name> means any event by that name.
505 * :<event-name> is the same.
506 *
507 * <subsystem>:* means all events in that subsystem
508 * <subsystem>: means the same.
509 *
510 * <name> (no ':') means all events in a subsystem with
511 * the name <name> or any event that matches <name>
512 */
513
514 match = strsep(&buf, ":");
515 if (buf) {
516 sub = match;
517 event = buf;
518 match = NULL;
519
520 if (!strlen(sub) || strcmp(sub, "*") == 0)
521 sub = NULL;
522 if (!strlen(event) || strcmp(event, "*") == 0)
523 event = NULL;
524 }
525
526 return __ftrace_set_clr_event(tr, match, sub, event, set);
527 }
528
529 /**
530 * trace_set_clr_event - enable or disable an event
531 * @system: system name to match (NULL for any system)
532 * @event: event name to match (NULL for all events, within system)
533 * @set: 1 to enable, 0 to disable
534 *
535 * This is a way for other parts of the kernel to enable or disable
536 * event recording.
537 *
538 * Returns 0 on success, -EINVAL if the parameters do not match any
539 * registered events.
540 */
541 int trace_set_clr_event(const char *system, const char *event, int set)
542 {
543 struct trace_array *tr = top_trace_array();
544
545 return __ftrace_set_clr_event(tr, NULL, system, event, set);
546 }
547 EXPORT_SYMBOL_GPL(trace_set_clr_event);
548
549 /* 128 should be much more than enough */
550 #define EVENT_BUF_SIZE 127
551
552 static ssize_t
553 ftrace_event_write(struct file *file, const char __user *ubuf,
554 size_t cnt, loff_t *ppos)
555 {
556 struct trace_parser parser;
557 struct seq_file *m = file->private_data;
558 struct trace_array *tr = m->private;
559 ssize_t read, ret;
560
561 if (!cnt)
562 return 0;
563
564 ret = tracing_update_buffers();
565 if (ret < 0)
566 return ret;
567
568 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
569 return -ENOMEM;
570
571 read = trace_get_user(&parser, ubuf, cnt, ppos);
572
573 if (read >= 0 && trace_parser_loaded((&parser))) {
574 int set = 1;
575
576 if (*parser.buffer == '!')
577 set = 0;
578
579 parser.buffer[parser.idx] = 0;
580
581 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
582 if (ret)
583 goto out_put;
584 }
585
586 ret = read;
587
588 out_put:
589 trace_parser_put(&parser);
590
591 return ret;
592 }
593
594 static void *
595 t_next(struct seq_file *m, void *v, loff_t *pos)
596 {
597 struct ftrace_event_file *file = v;
598 struct ftrace_event_call *call;
599 struct trace_array *tr = m->private;
600
601 (*pos)++;
602
603 list_for_each_entry_continue(file, &tr->events, list) {
604 call = file->event_call;
605 /*
606 * The ftrace subsystem is for showing formats only.
607 * They can not be enabled or disabled via the event files.
608 */
609 if (call->class && call->class->reg)
610 return file;
611 }
612
613 return NULL;
614 }
615
616 static void *t_start(struct seq_file *m, loff_t *pos)
617 {
618 struct ftrace_event_file *file;
619 struct trace_array *tr = m->private;
620 loff_t l;
621
622 mutex_lock(&event_mutex);
623
624 file = list_entry(&tr->events, struct ftrace_event_file, list);
625 for (l = 0; l <= *pos; ) {
626 file = t_next(m, file, &l);
627 if (!file)
628 break;
629 }
630 return file;
631 }
632
633 static void *
634 s_next(struct seq_file *m, void *v, loff_t *pos)
635 {
636 struct ftrace_event_file *file = v;
637 struct trace_array *tr = m->private;
638
639 (*pos)++;
640
641 list_for_each_entry_continue(file, &tr->events, list) {
642 if (file->flags & FTRACE_EVENT_FL_ENABLED)
643 return file;
644 }
645
646 return NULL;
647 }
648
649 static void *s_start(struct seq_file *m, loff_t *pos)
650 {
651 struct ftrace_event_file *file;
652 struct trace_array *tr = m->private;
653 loff_t l;
654
655 mutex_lock(&event_mutex);
656
657 file = list_entry(&tr->events, struct ftrace_event_file, list);
658 for (l = 0; l <= *pos; ) {
659 file = s_next(m, file, &l);
660 if (!file)
661 break;
662 }
663 return file;
664 }
665
666 static int t_show(struct seq_file *m, void *v)
667 {
668 struct ftrace_event_file *file = v;
669 struct ftrace_event_call *call = file->event_call;
670
671 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
672 seq_printf(m, "%s:", call->class->system);
673 seq_printf(m, "%s\n", call->name);
674
675 return 0;
676 }
677
678 static void t_stop(struct seq_file *m, void *p)
679 {
680 mutex_unlock(&event_mutex);
681 }
682
683 static ssize_t
684 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
685 loff_t *ppos)
686 {
687 struct ftrace_event_file *file;
688 unsigned long flags;
689 char buf[4] = "0";
690
691 mutex_lock(&event_mutex);
692 file = event_file_data(filp);
693 if (likely(file))
694 flags = file->flags;
695 mutex_unlock(&event_mutex);
696
697 if (!file)
698 return -ENODEV;
699
700 if (flags & FTRACE_EVENT_FL_ENABLED &&
701 !(flags & FTRACE_EVENT_FL_SOFT_DISABLED))
702 strcpy(buf, "1");
703
704 if (flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
705 flags & FTRACE_EVENT_FL_SOFT_MODE)
706 strcat(buf, "*");
707
708 strcat(buf, "\n");
709
710 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
711 }
712
713 static ssize_t
714 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
715 loff_t *ppos)
716 {
717 struct ftrace_event_file *file;
718 unsigned long val;
719 int ret;
720
721 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
722 if (ret)
723 return ret;
724
725 ret = tracing_update_buffers();
726 if (ret < 0)
727 return ret;
728
729 switch (val) {
730 case 0:
731 case 1:
732 ret = -ENODEV;
733 mutex_lock(&event_mutex);
734 file = event_file_data(filp);
735 if (likely(file))
736 ret = ftrace_event_enable_disable(file, val);
737 mutex_unlock(&event_mutex);
738 break;
739
740 default:
741 return -EINVAL;
742 }
743
744 *ppos += cnt;
745
746 return ret ? ret : cnt;
747 }
748
749 static ssize_t
750 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
751 loff_t *ppos)
752 {
753 const char set_to_char[4] = { '?', '0', '1', 'X' };
754 struct ftrace_subsystem_dir *dir = filp->private_data;
755 struct event_subsystem *system = dir->subsystem;
756 struct ftrace_event_call *call;
757 struct ftrace_event_file *file;
758 struct trace_array *tr = dir->tr;
759 char buf[2];
760 int set = 0;
761 int ret;
762
763 mutex_lock(&event_mutex);
764 list_for_each_entry(file, &tr->events, list) {
765 call = file->event_call;
766 if (!call->name || !call->class || !call->class->reg)
767 continue;
768
769 if (system && strcmp(call->class->system, system->name) != 0)
770 continue;
771
772 /*
773 * We need to find out if all the events are set
774 * or if all events or cleared, or if we have
775 * a mixture.
776 */
777 set |= (1 << !!(file->flags & FTRACE_EVENT_FL_ENABLED));
778
779 /*
780 * If we have a mixture, no need to look further.
781 */
782 if (set == 3)
783 break;
784 }
785 mutex_unlock(&event_mutex);
786
787 buf[0] = set_to_char[set];
788 buf[1] = '\n';
789
790 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
791
792 return ret;
793 }
794
795 static ssize_t
796 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
797 loff_t *ppos)
798 {
799 struct ftrace_subsystem_dir *dir = filp->private_data;
800 struct event_subsystem *system = dir->subsystem;
801 const char *name = NULL;
802 unsigned long val;
803 ssize_t ret;
804
805 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
806 if (ret)
807 return ret;
808
809 ret = tracing_update_buffers();
810 if (ret < 0)
811 return ret;
812
813 if (val != 0 && val != 1)
814 return -EINVAL;
815
816 /*
817 * Opening of "enable" adds a ref count to system,
818 * so the name is safe to use.
819 */
820 if (system)
821 name = system->name;
822
823 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
824 if (ret)
825 goto out;
826
827 ret = cnt;
828
829 out:
830 *ppos += cnt;
831
832 return ret;
833 }
834
835 enum {
836 FORMAT_HEADER = 1,
837 FORMAT_FIELD_SEPERATOR = 2,
838 FORMAT_PRINTFMT = 3,
839 };
840
841 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
842 {
843 struct ftrace_event_call *call = m->private;
844 struct list_head *common_head = &ftrace_common_fields;
845 struct list_head *head = trace_get_fields(call);
846 struct list_head *node = v;
847
848 (*pos)++;
849
850 switch ((unsigned long)v) {
851 case FORMAT_HEADER:
852 node = common_head;
853 break;
854
855 case FORMAT_FIELD_SEPERATOR:
856 node = head;
857 break;
858
859 case FORMAT_PRINTFMT:
860 /* all done */
861 return NULL;
862 }
863
864 node = node->prev;
865 if (node == common_head)
866 return (void *)FORMAT_FIELD_SEPERATOR;
867 else if (node == head)
868 return (void *)FORMAT_PRINTFMT;
869 else
870 return node;
871 }
872
873 static int f_show(struct seq_file *m, void *v)
874 {
875 struct ftrace_event_call *call = m->private;
876 struct ftrace_event_field *field;
877 const char *array_descriptor;
878
879 switch ((unsigned long)v) {
880 case FORMAT_HEADER:
881 seq_printf(m, "name: %s\n", call->name);
882 seq_printf(m, "ID: %d\n", call->event.type);
883 seq_printf(m, "format:\n");
884 return 0;
885
886 case FORMAT_FIELD_SEPERATOR:
887 seq_putc(m, '\n');
888 return 0;
889
890 case FORMAT_PRINTFMT:
891 seq_printf(m, "\nprint fmt: %s\n",
892 call->print_fmt);
893 return 0;
894 }
895
896 field = list_entry(v, struct ftrace_event_field, link);
897 /*
898 * Smartly shows the array type(except dynamic array).
899 * Normal:
900 * field:TYPE VAR
901 * If TYPE := TYPE[LEN], it is shown:
902 * field:TYPE VAR[LEN]
903 */
904 array_descriptor = strchr(field->type, '[');
905
906 if (!strncmp(field->type, "__data_loc", 10))
907 array_descriptor = NULL;
908
909 if (!array_descriptor)
910 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
911 field->type, field->name, field->offset,
912 field->size, !!field->is_signed);
913 else
914 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
915 (int)(array_descriptor - field->type),
916 field->type, field->name,
917 array_descriptor, field->offset,
918 field->size, !!field->is_signed);
919
920 return 0;
921 }
922
923 static void *f_start(struct seq_file *m, loff_t *pos)
924 {
925 void *p = (void *)FORMAT_HEADER;
926 loff_t l = 0;
927
928 while (l < *pos && p)
929 p = f_next(m, p, &l);
930
931 return p;
932 }
933
934 static void f_stop(struct seq_file *m, void *p)
935 {
936 }
937
938 static const struct seq_operations trace_format_seq_ops = {
939 .start = f_start,
940 .next = f_next,
941 .stop = f_stop,
942 .show = f_show,
943 };
944
945 static int trace_format_open(struct inode *inode, struct file *file)
946 {
947 struct ftrace_event_call *call = inode->i_private;
948 struct seq_file *m;
949 int ret;
950
951 ret = seq_open(file, &trace_format_seq_ops);
952 if (ret < 0)
953 return ret;
954
955 m = file->private_data;
956 m->private = call;
957
958 return 0;
959 }
960
961 static ssize_t
962 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
963 {
964 int id = (long)event_file_data(filp);
965 char buf[32];
966 int len;
967
968 if (*ppos)
969 return 0;
970
971 if (unlikely(!id))
972 return -ENODEV;
973
974 len = sprintf(buf, "%d\n", id);
975
976 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
977 }
978
979 static ssize_t
980 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
981 loff_t *ppos)
982 {
983 struct ftrace_event_call *call = filp->private_data;
984 struct trace_seq *s;
985 int r;
986
987 if (*ppos)
988 return 0;
989
990 s = kmalloc(sizeof(*s), GFP_KERNEL);
991 if (!s)
992 return -ENOMEM;
993
994 trace_seq_init(s);
995
996 print_event_filter(call, s);
997 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
998
999 kfree(s);
1000
1001 return r;
1002 }
1003
1004 static ssize_t
1005 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1006 loff_t *ppos)
1007 {
1008 struct ftrace_event_call *call = filp->private_data;
1009 char *buf;
1010 int err;
1011
1012 if (cnt >= PAGE_SIZE)
1013 return -EINVAL;
1014
1015 buf = (char *)__get_free_page(GFP_TEMPORARY);
1016 if (!buf)
1017 return -ENOMEM;
1018
1019 if (copy_from_user(buf, ubuf, cnt)) {
1020 free_page((unsigned long) buf);
1021 return -EFAULT;
1022 }
1023 buf[cnt] = '\0';
1024
1025 err = apply_event_filter(call, buf);
1026 free_page((unsigned long) buf);
1027 if (err < 0)
1028 return err;
1029
1030 *ppos += cnt;
1031
1032 return cnt;
1033 }
1034
1035 static LIST_HEAD(event_subsystems);
1036
1037 static int subsystem_open(struct inode *inode, struct file *filp)
1038 {
1039 struct event_subsystem *system = NULL;
1040 struct ftrace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1041 struct trace_array *tr;
1042 int ret;
1043
1044 /* Make sure the system still exists */
1045 mutex_lock(&trace_types_lock);
1046 mutex_lock(&event_mutex);
1047 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1048 list_for_each_entry(dir, &tr->systems, list) {
1049 if (dir == inode->i_private) {
1050 /* Don't open systems with no events */
1051 if (dir->nr_events) {
1052 __get_system_dir(dir);
1053 system = dir->subsystem;
1054 }
1055 goto exit_loop;
1056 }
1057 }
1058 }
1059 exit_loop:
1060 mutex_unlock(&event_mutex);
1061 mutex_unlock(&trace_types_lock);
1062
1063 if (!system)
1064 return -ENODEV;
1065
1066 /* Some versions of gcc think dir can be uninitialized here */
1067 WARN_ON(!dir);
1068
1069 /* Still need to increment the ref count of the system */
1070 if (trace_array_get(tr) < 0) {
1071 put_system(dir);
1072 return -ENODEV;
1073 }
1074
1075 ret = tracing_open_generic(inode, filp);
1076 if (ret < 0) {
1077 trace_array_put(tr);
1078 put_system(dir);
1079 }
1080
1081 return ret;
1082 }
1083
1084 static int system_tr_open(struct inode *inode, struct file *filp)
1085 {
1086 struct ftrace_subsystem_dir *dir;
1087 struct trace_array *tr = inode->i_private;
1088 int ret;
1089
1090 if (trace_array_get(tr) < 0)
1091 return -ENODEV;
1092
1093 /* Make a temporary dir that has no system but points to tr */
1094 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1095 if (!dir) {
1096 trace_array_put(tr);
1097 return -ENOMEM;
1098 }
1099
1100 dir->tr = tr;
1101
1102 ret = tracing_open_generic(inode, filp);
1103 if (ret < 0) {
1104 trace_array_put(tr);
1105 kfree(dir);
1106 }
1107
1108 filp->private_data = dir;
1109
1110 return ret;
1111 }
1112
1113 static int subsystem_release(struct inode *inode, struct file *file)
1114 {
1115 struct ftrace_subsystem_dir *dir = file->private_data;
1116
1117 trace_array_put(dir->tr);
1118
1119 /*
1120 * If dir->subsystem is NULL, then this is a temporary
1121 * descriptor that was made for a trace_array to enable
1122 * all subsystems.
1123 */
1124 if (dir->subsystem)
1125 put_system(dir);
1126 else
1127 kfree(dir);
1128
1129 return 0;
1130 }
1131
1132 static ssize_t
1133 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1134 loff_t *ppos)
1135 {
1136 struct ftrace_subsystem_dir *dir = filp->private_data;
1137 struct event_subsystem *system = dir->subsystem;
1138 struct trace_seq *s;
1139 int r;
1140
1141 if (*ppos)
1142 return 0;
1143
1144 s = kmalloc(sizeof(*s), GFP_KERNEL);
1145 if (!s)
1146 return -ENOMEM;
1147
1148 trace_seq_init(s);
1149
1150 print_subsystem_event_filter(system, s);
1151 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1152
1153 kfree(s);
1154
1155 return r;
1156 }
1157
1158 static ssize_t
1159 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1160 loff_t *ppos)
1161 {
1162 struct ftrace_subsystem_dir *dir = filp->private_data;
1163 char *buf;
1164 int err;
1165
1166 if (cnt >= PAGE_SIZE)
1167 return -EINVAL;
1168
1169 buf = (char *)__get_free_page(GFP_TEMPORARY);
1170 if (!buf)
1171 return -ENOMEM;
1172
1173 if (copy_from_user(buf, ubuf, cnt)) {
1174 free_page((unsigned long) buf);
1175 return -EFAULT;
1176 }
1177 buf[cnt] = '\0';
1178
1179 err = apply_subsystem_event_filter(dir, buf);
1180 free_page((unsigned long) buf);
1181 if (err < 0)
1182 return err;
1183
1184 *ppos += cnt;
1185
1186 return cnt;
1187 }
1188
1189 static ssize_t
1190 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1191 {
1192 int (*func)(struct trace_seq *s) = filp->private_data;
1193 struct trace_seq *s;
1194 int r;
1195
1196 if (*ppos)
1197 return 0;
1198
1199 s = kmalloc(sizeof(*s), GFP_KERNEL);
1200 if (!s)
1201 return -ENOMEM;
1202
1203 trace_seq_init(s);
1204
1205 func(s);
1206 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1207
1208 kfree(s);
1209
1210 return r;
1211 }
1212
1213 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1214 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1215 static int ftrace_event_release(struct inode *inode, struct file *file);
1216
1217 static const struct seq_operations show_event_seq_ops = {
1218 .start = t_start,
1219 .next = t_next,
1220 .show = t_show,
1221 .stop = t_stop,
1222 };
1223
1224 static const struct seq_operations show_set_event_seq_ops = {
1225 .start = s_start,
1226 .next = s_next,
1227 .show = t_show,
1228 .stop = t_stop,
1229 };
1230
1231 static const struct file_operations ftrace_avail_fops = {
1232 .open = ftrace_event_avail_open,
1233 .read = seq_read,
1234 .llseek = seq_lseek,
1235 .release = seq_release,
1236 };
1237
1238 static const struct file_operations ftrace_set_event_fops = {
1239 .open = ftrace_event_set_open,
1240 .read = seq_read,
1241 .write = ftrace_event_write,
1242 .llseek = seq_lseek,
1243 .release = ftrace_event_release,
1244 };
1245
1246 static const struct file_operations ftrace_enable_fops = {
1247 .open = tracing_open_generic_file,
1248 .read = event_enable_read,
1249 .write = event_enable_write,
1250 .release = tracing_release_generic_file,
1251 .llseek = default_llseek,
1252 };
1253
1254 static const struct file_operations ftrace_event_format_fops = {
1255 .open = trace_format_open,
1256 .read = seq_read,
1257 .llseek = seq_lseek,
1258 .release = seq_release,
1259 };
1260
1261 static const struct file_operations ftrace_event_id_fops = {
1262 .read = event_id_read,
1263 .llseek = default_llseek,
1264 };
1265
1266 static const struct file_operations ftrace_event_filter_fops = {
1267 .open = tracing_open_generic,
1268 .read = event_filter_read,
1269 .write = event_filter_write,
1270 .llseek = default_llseek,
1271 };
1272
1273 static const struct file_operations ftrace_subsystem_filter_fops = {
1274 .open = subsystem_open,
1275 .read = subsystem_filter_read,
1276 .write = subsystem_filter_write,
1277 .llseek = default_llseek,
1278 .release = subsystem_release,
1279 };
1280
1281 static const struct file_operations ftrace_system_enable_fops = {
1282 .open = subsystem_open,
1283 .read = system_enable_read,
1284 .write = system_enable_write,
1285 .llseek = default_llseek,
1286 .release = subsystem_release,
1287 };
1288
1289 static const struct file_operations ftrace_tr_enable_fops = {
1290 .open = system_tr_open,
1291 .read = system_enable_read,
1292 .write = system_enable_write,
1293 .llseek = default_llseek,
1294 .release = subsystem_release,
1295 };
1296
1297 static const struct file_operations ftrace_show_header_fops = {
1298 .open = tracing_open_generic,
1299 .read = show_header,
1300 .llseek = default_llseek,
1301 };
1302
1303 static int
1304 ftrace_event_open(struct inode *inode, struct file *file,
1305 const struct seq_operations *seq_ops)
1306 {
1307 struct seq_file *m;
1308 int ret;
1309
1310 ret = seq_open(file, seq_ops);
1311 if (ret < 0)
1312 return ret;
1313 m = file->private_data;
1314 /* copy tr over to seq ops */
1315 m->private = inode->i_private;
1316
1317 return ret;
1318 }
1319
1320 static int ftrace_event_release(struct inode *inode, struct file *file)
1321 {
1322 struct trace_array *tr = inode->i_private;
1323
1324 trace_array_put(tr);
1325
1326 return seq_release(inode, file);
1327 }
1328
1329 static int
1330 ftrace_event_avail_open(struct inode *inode, struct file *file)
1331 {
1332 const struct seq_operations *seq_ops = &show_event_seq_ops;
1333
1334 return ftrace_event_open(inode, file, seq_ops);
1335 }
1336
1337 static int
1338 ftrace_event_set_open(struct inode *inode, struct file *file)
1339 {
1340 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1341 struct trace_array *tr = inode->i_private;
1342 int ret;
1343
1344 if (trace_array_get(tr) < 0)
1345 return -ENODEV;
1346
1347 if ((file->f_mode & FMODE_WRITE) &&
1348 (file->f_flags & O_TRUNC))
1349 ftrace_clear_events(tr);
1350
1351 ret = ftrace_event_open(inode, file, seq_ops);
1352 if (ret < 0)
1353 trace_array_put(tr);
1354 return ret;
1355 }
1356
1357 static struct event_subsystem *
1358 create_new_subsystem(const char *name)
1359 {
1360 struct event_subsystem *system;
1361
1362 /* need to create new entry */
1363 system = kmalloc(sizeof(*system), GFP_KERNEL);
1364 if (!system)
1365 return NULL;
1366
1367 system->ref_count = 1;
1368
1369 /* Only allocate if dynamic (kprobes and modules) */
1370 if (!core_kernel_data((unsigned long)name)) {
1371 system->ref_count |= SYSTEM_FL_FREE_NAME;
1372 system->name = kstrdup(name, GFP_KERNEL);
1373 if (!system->name)
1374 goto out_free;
1375 } else
1376 system->name = name;
1377
1378 system->filter = NULL;
1379
1380 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1381 if (!system->filter)
1382 goto out_free;
1383
1384 list_add(&system->list, &event_subsystems);
1385
1386 return system;
1387
1388 out_free:
1389 if (system->ref_count & SYSTEM_FL_FREE_NAME)
1390 kfree(system->name);
1391 kfree(system);
1392 return NULL;
1393 }
1394
1395 static struct dentry *
1396 event_subsystem_dir(struct trace_array *tr, const char *name,
1397 struct ftrace_event_file *file, struct dentry *parent)
1398 {
1399 struct ftrace_subsystem_dir *dir;
1400 struct event_subsystem *system;
1401 struct dentry *entry;
1402
1403 /* First see if we did not already create this dir */
1404 list_for_each_entry(dir, &tr->systems, list) {
1405 system = dir->subsystem;
1406 if (strcmp(system->name, name) == 0) {
1407 dir->nr_events++;
1408 file->system = dir;
1409 return dir->entry;
1410 }
1411 }
1412
1413 /* Now see if the system itself exists. */
1414 list_for_each_entry(system, &event_subsystems, list) {
1415 if (strcmp(system->name, name) == 0)
1416 break;
1417 }
1418 /* Reset system variable when not found */
1419 if (&system->list == &event_subsystems)
1420 system = NULL;
1421
1422 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1423 if (!dir)
1424 goto out_fail;
1425
1426 if (!system) {
1427 system = create_new_subsystem(name);
1428 if (!system)
1429 goto out_free;
1430 } else
1431 __get_system(system);
1432
1433 dir->entry = debugfs_create_dir(name, parent);
1434 if (!dir->entry) {
1435 pr_warning("Failed to create system directory %s\n", name);
1436 __put_system(system);
1437 goto out_free;
1438 }
1439
1440 dir->tr = tr;
1441 dir->ref_count = 1;
1442 dir->nr_events = 1;
1443 dir->subsystem = system;
1444 file->system = dir;
1445
1446 entry = debugfs_create_file("filter", 0644, dir->entry, dir,
1447 &ftrace_subsystem_filter_fops);
1448 if (!entry) {
1449 kfree(system->filter);
1450 system->filter = NULL;
1451 pr_warning("Could not create debugfs '%s/filter' entry\n", name);
1452 }
1453
1454 trace_create_file("enable", 0644, dir->entry, dir,
1455 &ftrace_system_enable_fops);
1456
1457 list_add(&dir->list, &tr->systems);
1458
1459 return dir->entry;
1460
1461 out_free:
1462 kfree(dir);
1463 out_fail:
1464 /* Only print this message if failed on memory allocation */
1465 if (!dir || !system)
1466 pr_warning("No memory to create event subsystem %s\n",
1467 name);
1468 return NULL;
1469 }
1470
1471 static int
1472 event_create_dir(struct dentry *parent,
1473 struct ftrace_event_file *file,
1474 const struct file_operations *id,
1475 const struct file_operations *enable,
1476 const struct file_operations *filter,
1477 const struct file_operations *format)
1478 {
1479 struct ftrace_event_call *call = file->event_call;
1480 struct trace_array *tr = file->tr;
1481 struct list_head *head;
1482 struct dentry *d_events;
1483 int ret;
1484
1485 /*
1486 * If the trace point header did not define TRACE_SYSTEM
1487 * then the system would be called "TRACE_SYSTEM".
1488 */
1489 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1490 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1491 if (!d_events)
1492 return -ENOMEM;
1493 } else
1494 d_events = parent;
1495
1496 file->dir = debugfs_create_dir(call->name, d_events);
1497 if (!file->dir) {
1498 pr_warning("Could not create debugfs '%s' directory\n",
1499 call->name);
1500 return -1;
1501 }
1502
1503 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1504 trace_create_file("enable", 0644, file->dir, file,
1505 enable);
1506
1507 #ifdef CONFIG_PERF_EVENTS
1508 if (call->event.type && call->class->reg)
1509 trace_create_file("id", 0444, file->dir,
1510 (void *)(long)call->event.type, id);
1511 #endif
1512
1513 /*
1514 * Other events may have the same class. Only update
1515 * the fields if they are not already defined.
1516 */
1517 head = trace_get_fields(call);
1518 if (list_empty(head)) {
1519 ret = call->class->define_fields(call);
1520 if (ret < 0) {
1521 pr_warning("Could not initialize trace point"
1522 " events/%s\n", call->name);
1523 return -1;
1524 }
1525 }
1526 trace_create_file("filter", 0644, file->dir, call,
1527 filter);
1528
1529 trace_create_file("format", 0444, file->dir, call,
1530 format);
1531
1532 return 0;
1533 }
1534
1535 static void remove_subsystem(struct ftrace_subsystem_dir *dir)
1536 {
1537 if (!dir)
1538 return;
1539
1540 if (!--dir->nr_events) {
1541 debugfs_remove_recursive(dir->entry);
1542 list_del(&dir->list);
1543 __put_system_dir(dir);
1544 }
1545 }
1546
1547 static void remove_event_from_tracers(struct ftrace_event_call *call)
1548 {
1549 struct ftrace_event_file *file;
1550 struct trace_array *tr;
1551
1552 do_for_each_event_file_safe(tr, file) {
1553
1554 if (file->event_call != call)
1555 continue;
1556
1557 list_del(&file->list);
1558 debugfs_remove_recursive(file->dir);
1559 remove_subsystem(file->system);
1560 kmem_cache_free(file_cachep, file);
1561
1562 /*
1563 * The do_for_each_event_file_safe() is
1564 * a double loop. After finding the call for this
1565 * trace_array, we use break to jump to the next
1566 * trace_array.
1567 */
1568 break;
1569 } while_for_each_event_file();
1570 }
1571
1572 static void event_remove(struct ftrace_event_call *call)
1573 {
1574 struct trace_array *tr;
1575 struct ftrace_event_file *file;
1576
1577 do_for_each_event_file(tr, file) {
1578 if (file->event_call != call)
1579 continue;
1580 ftrace_event_enable_disable(file, 0);
1581 /*
1582 * The do_for_each_event_file() is
1583 * a double loop. After finding the call for this
1584 * trace_array, we use break to jump to the next
1585 * trace_array.
1586 */
1587 break;
1588 } while_for_each_event_file();
1589
1590 if (call->event.funcs)
1591 __unregister_ftrace_event(&call->event);
1592 remove_event_from_tracers(call);
1593 list_del(&call->list);
1594 }
1595
1596 static int event_init(struct ftrace_event_call *call)
1597 {
1598 int ret = 0;
1599
1600 if (WARN_ON(!call->name))
1601 return -EINVAL;
1602
1603 if (call->class->raw_init) {
1604 ret = call->class->raw_init(call);
1605 if (ret < 0 && ret != -ENOSYS)
1606 pr_warn("Could not initialize trace events/%s\n",
1607 call->name);
1608 }
1609
1610 return ret;
1611 }
1612
1613 static int
1614 __register_event(struct ftrace_event_call *call, struct module *mod)
1615 {
1616 int ret;
1617
1618 ret = event_init(call);
1619 if (ret < 0)
1620 return ret;
1621
1622 list_add(&call->list, &ftrace_events);
1623 call->mod = mod;
1624
1625 return 0;
1626 }
1627
1628 static struct ftrace_event_file *
1629 trace_create_new_event(struct ftrace_event_call *call,
1630 struct trace_array *tr)
1631 {
1632 struct ftrace_event_file *file;
1633
1634 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
1635 if (!file)
1636 return NULL;
1637
1638 file->event_call = call;
1639 file->tr = tr;
1640 atomic_set(&file->sm_ref, 0);
1641 list_add(&file->list, &tr->events);
1642
1643 return file;
1644 }
1645
1646 /* Add an event to a trace directory */
1647 static int
1648 __trace_add_new_event(struct ftrace_event_call *call,
1649 struct trace_array *tr,
1650 const struct file_operations *id,
1651 const struct file_operations *enable,
1652 const struct file_operations *filter,
1653 const struct file_operations *format)
1654 {
1655 struct ftrace_event_file *file;
1656
1657 file = trace_create_new_event(call, tr);
1658 if (!file)
1659 return -ENOMEM;
1660
1661 return event_create_dir(tr->event_dir, file, id, enable, filter, format);
1662 }
1663
1664 /*
1665 * Just create a decriptor for early init. A descriptor is required
1666 * for enabling events at boot. We want to enable events before
1667 * the filesystem is initialized.
1668 */
1669 static __init int
1670 __trace_early_add_new_event(struct ftrace_event_call *call,
1671 struct trace_array *tr)
1672 {
1673 struct ftrace_event_file *file;
1674
1675 file = trace_create_new_event(call, tr);
1676 if (!file)
1677 return -ENOMEM;
1678
1679 return 0;
1680 }
1681
1682 struct ftrace_module_file_ops;
1683 static void __add_event_to_tracers(struct ftrace_event_call *call,
1684 struct ftrace_module_file_ops *file_ops);
1685
1686 /* Add an additional event_call dynamically */
1687 int trace_add_event_call(struct ftrace_event_call *call)
1688 {
1689 int ret;
1690 mutex_lock(&trace_types_lock);
1691 mutex_lock(&event_mutex);
1692
1693 ret = __register_event(call, NULL);
1694 if (ret >= 0)
1695 __add_event_to_tracers(call, NULL);
1696
1697 mutex_unlock(&event_mutex);
1698 mutex_unlock(&trace_types_lock);
1699 return ret;
1700 }
1701
1702 /*
1703 * Must be called under locking of trace_types_lock, event_mutex and
1704 * trace_event_sem.
1705 */
1706 static void __trace_remove_event_call(struct ftrace_event_call *call)
1707 {
1708 event_remove(call);
1709 trace_destroy_fields(call);
1710 destroy_preds(call);
1711 }
1712
1713 /* Remove an event_call */
1714 void trace_remove_event_call(struct ftrace_event_call *call)
1715 {
1716 mutex_lock(&trace_types_lock);
1717 mutex_lock(&event_mutex);
1718 down_write(&trace_event_sem);
1719 __trace_remove_event_call(call);
1720 up_write(&trace_event_sem);
1721 mutex_unlock(&event_mutex);
1722 mutex_unlock(&trace_types_lock);
1723 }
1724
1725 #define for_each_event(event, start, end) \
1726 for (event = start; \
1727 (unsigned long)event < (unsigned long)end; \
1728 event++)
1729
1730 #ifdef CONFIG_MODULES
1731
1732 static LIST_HEAD(ftrace_module_file_list);
1733
1734 /*
1735 * Modules must own their file_operations to keep up with
1736 * reference counting.
1737 */
1738 struct ftrace_module_file_ops {
1739 struct list_head list;
1740 struct module *mod;
1741 struct file_operations id;
1742 struct file_operations enable;
1743 struct file_operations format;
1744 struct file_operations filter;
1745 };
1746
1747 static struct ftrace_module_file_ops *
1748 find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
1749 {
1750 /*
1751 * As event_calls are added in groups by module,
1752 * when we find one file_ops, we don't need to search for
1753 * each call in that module, as the rest should be the
1754 * same. Only search for a new one if the last one did
1755 * not match.
1756 */
1757 if (file_ops && mod == file_ops->mod)
1758 return file_ops;
1759
1760 list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1761 if (file_ops->mod == mod)
1762 return file_ops;
1763 }
1764 return NULL;
1765 }
1766
1767 static struct ftrace_module_file_ops *
1768 trace_create_file_ops(struct module *mod)
1769 {
1770 struct ftrace_module_file_ops *file_ops;
1771
1772 /*
1773 * This is a bit of a PITA. To allow for correct reference
1774 * counting, modules must "own" their file_operations.
1775 * To do this, we allocate the file operations that will be
1776 * used in the event directory.
1777 */
1778
1779 file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1780 if (!file_ops)
1781 return NULL;
1782
1783 file_ops->mod = mod;
1784
1785 file_ops->id = ftrace_event_id_fops;
1786 file_ops->id.owner = mod;
1787
1788 file_ops->enable = ftrace_enable_fops;
1789 file_ops->enable.owner = mod;
1790
1791 file_ops->filter = ftrace_event_filter_fops;
1792 file_ops->filter.owner = mod;
1793
1794 file_ops->format = ftrace_event_format_fops;
1795 file_ops->format.owner = mod;
1796
1797 list_add(&file_ops->list, &ftrace_module_file_list);
1798
1799 return file_ops;
1800 }
1801
1802 static void trace_module_add_events(struct module *mod)
1803 {
1804 struct ftrace_module_file_ops *file_ops = NULL;
1805 struct ftrace_event_call **call, **start, **end;
1806
1807 start = mod->trace_events;
1808 end = mod->trace_events + mod->num_trace_events;
1809
1810 if (start == end)
1811 return;
1812
1813 file_ops = trace_create_file_ops(mod);
1814 if (!file_ops)
1815 return;
1816
1817 for_each_event(call, start, end) {
1818 __register_event(*call, mod);
1819 __add_event_to_tracers(*call, file_ops);
1820 }
1821 }
1822
1823 static void trace_module_remove_events(struct module *mod)
1824 {
1825 struct ftrace_module_file_ops *file_ops;
1826 struct ftrace_event_call *call, *p;
1827 bool clear_trace = false;
1828
1829 down_write(&trace_event_sem);
1830 list_for_each_entry_safe(call, p, &ftrace_events, list) {
1831 if (call->mod == mod) {
1832 if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
1833 clear_trace = true;
1834 __trace_remove_event_call(call);
1835 }
1836 }
1837
1838 /* Now free the file_operations */
1839 list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1840 if (file_ops->mod == mod)
1841 break;
1842 }
1843 if (&file_ops->list != &ftrace_module_file_list) {
1844 list_del(&file_ops->list);
1845 kfree(file_ops);
1846 }
1847 up_write(&trace_event_sem);
1848
1849 /*
1850 * It is safest to reset the ring buffer if the module being unloaded
1851 * registered any events that were used. The only worry is if
1852 * a new module gets loaded, and takes on the same id as the events
1853 * of this module. When printing out the buffer, traced events left
1854 * over from this module may be passed to the new module events and
1855 * unexpected results may occur.
1856 */
1857 if (clear_trace)
1858 tracing_reset_all_online_cpus();
1859 }
1860
1861 static int trace_module_notify(struct notifier_block *self,
1862 unsigned long val, void *data)
1863 {
1864 struct module *mod = data;
1865
1866 mutex_lock(&trace_types_lock);
1867 mutex_lock(&event_mutex);
1868 switch (val) {
1869 case MODULE_STATE_COMING:
1870 trace_module_add_events(mod);
1871 break;
1872 case MODULE_STATE_GOING:
1873 trace_module_remove_events(mod);
1874 break;
1875 }
1876 mutex_unlock(&event_mutex);
1877 mutex_unlock(&trace_types_lock);
1878
1879 return 0;
1880 }
1881
1882 static int
1883 __trace_add_new_mod_event(struct ftrace_event_call *call,
1884 struct trace_array *tr,
1885 struct ftrace_module_file_ops *file_ops)
1886 {
1887 return __trace_add_new_event(call, tr,
1888 &file_ops->id, &file_ops->enable,
1889 &file_ops->filter, &file_ops->format);
1890 }
1891
1892 #else
1893 static inline struct ftrace_module_file_ops *
1894 find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
1895 {
1896 return NULL;
1897 }
1898 static inline int trace_module_notify(struct notifier_block *self,
1899 unsigned long val, void *data)
1900 {
1901 return 0;
1902 }
1903 static inline int
1904 __trace_add_new_mod_event(struct ftrace_event_call *call,
1905 struct trace_array *tr,
1906 struct ftrace_module_file_ops *file_ops)
1907 {
1908 return -ENODEV;
1909 }
1910 #endif /* CONFIG_MODULES */
1911
1912 /* Create a new event directory structure for a trace directory. */
1913 static void
1914 __trace_add_event_dirs(struct trace_array *tr)
1915 {
1916 struct ftrace_module_file_ops *file_ops = NULL;
1917 struct ftrace_event_call *call;
1918 int ret;
1919
1920 list_for_each_entry(call, &ftrace_events, list) {
1921 if (call->mod) {
1922 /*
1923 * Directories for events by modules need to
1924 * keep module ref counts when opened (as we don't
1925 * want the module to disappear when reading one
1926 * of these files). The file_ops keep account of
1927 * the module ref count.
1928 */
1929 file_ops = find_ftrace_file_ops(file_ops, call->mod);
1930 if (!file_ops)
1931 continue; /* Warn? */
1932 ret = __trace_add_new_mod_event(call, tr, file_ops);
1933 if (ret < 0)
1934 pr_warning("Could not create directory for event %s\n",
1935 call->name);
1936 continue;
1937 }
1938 ret = __trace_add_new_event(call, tr,
1939 &ftrace_event_id_fops,
1940 &ftrace_enable_fops,
1941 &ftrace_event_filter_fops,
1942 &ftrace_event_format_fops);
1943 if (ret < 0)
1944 pr_warning("Could not create directory for event %s\n",
1945 call->name);
1946 }
1947 }
1948
1949 #ifdef CONFIG_DYNAMIC_FTRACE
1950
1951 /* Avoid typos */
1952 #define ENABLE_EVENT_STR "enable_event"
1953 #define DISABLE_EVENT_STR "disable_event"
1954
1955 struct event_probe_data {
1956 struct ftrace_event_file *file;
1957 unsigned long count;
1958 int ref;
1959 bool enable;
1960 };
1961
1962 static struct ftrace_event_file *
1963 find_event_file(struct trace_array *tr, const char *system, const char *event)
1964 {
1965 struct ftrace_event_file *file;
1966 struct ftrace_event_call *call;
1967
1968 list_for_each_entry(file, &tr->events, list) {
1969
1970 call = file->event_call;
1971
1972 if (!call->name || !call->class || !call->class->reg)
1973 continue;
1974
1975 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1976 continue;
1977
1978 if (strcmp(event, call->name) == 0 &&
1979 strcmp(system, call->class->system) == 0)
1980 return file;
1981 }
1982 return NULL;
1983 }
1984
1985 static void
1986 event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
1987 {
1988 struct event_probe_data **pdata = (struct event_probe_data **)_data;
1989 struct event_probe_data *data = *pdata;
1990
1991 if (!data)
1992 return;
1993
1994 if (data->enable)
1995 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1996 else
1997 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
1998 }
1999
2000 static void
2001 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
2002 {
2003 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2004 struct event_probe_data *data = *pdata;
2005
2006 if (!data)
2007 return;
2008
2009 if (!data->count)
2010 return;
2011
2012 /* Skip if the event is in a state we want to switch to */
2013 if (data->enable == !(data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
2014 return;
2015
2016 if (data->count != -1)
2017 (data->count)--;
2018
2019 event_enable_probe(ip, parent_ip, _data);
2020 }
2021
2022 static int
2023 event_enable_print(struct seq_file *m, unsigned long ip,
2024 struct ftrace_probe_ops *ops, void *_data)
2025 {
2026 struct event_probe_data *data = _data;
2027
2028 seq_printf(m, "%ps:", (void *)ip);
2029
2030 seq_printf(m, "%s:%s:%s",
2031 data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
2032 data->file->event_call->class->system,
2033 data->file->event_call->name);
2034
2035 if (data->count == -1)
2036 seq_printf(m, ":unlimited\n");
2037 else
2038 seq_printf(m, ":count=%ld\n", data->count);
2039
2040 return 0;
2041 }
2042
2043 static int
2044 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
2045 void **_data)
2046 {
2047 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2048 struct event_probe_data *data = *pdata;
2049
2050 data->ref++;
2051 return 0;
2052 }
2053
2054 static void
2055 event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
2056 void **_data)
2057 {
2058 struct event_probe_data **pdata = (struct event_probe_data **)_data;
2059 struct event_probe_data *data = *pdata;
2060
2061 if (WARN_ON_ONCE(data->ref <= 0))
2062 return;
2063
2064 data->ref--;
2065 if (!data->ref) {
2066 /* Remove the SOFT_MODE flag */
2067 __ftrace_event_enable_disable(data->file, 0, 1);
2068 module_put(data->file->event_call->mod);
2069 kfree(data);
2070 }
2071 *pdata = NULL;
2072 }
2073
2074 static struct ftrace_probe_ops event_enable_probe_ops = {
2075 .func = event_enable_probe,
2076 .print = event_enable_print,
2077 .init = event_enable_init,
2078 .free = event_enable_free,
2079 };
2080
2081 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2082 .func = event_enable_count_probe,
2083 .print = event_enable_print,
2084 .init = event_enable_init,
2085 .free = event_enable_free,
2086 };
2087
2088 static struct ftrace_probe_ops event_disable_probe_ops = {
2089 .func = event_enable_probe,
2090 .print = event_enable_print,
2091 .init = event_enable_init,
2092 .free = event_enable_free,
2093 };
2094
2095 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2096 .func = event_enable_count_probe,
2097 .print = event_enable_print,
2098 .init = event_enable_init,
2099 .free = event_enable_free,
2100 };
2101
2102 static int
2103 event_enable_func(struct ftrace_hash *hash,
2104 char *glob, char *cmd, char *param, int enabled)
2105 {
2106 struct trace_array *tr = top_trace_array();
2107 struct ftrace_event_file *file;
2108 struct ftrace_probe_ops *ops;
2109 struct event_probe_data *data;
2110 const char *system;
2111 const char *event;
2112 char *number;
2113 bool enable;
2114 int ret;
2115
2116 /* hash funcs only work with set_ftrace_filter */
2117 if (!enabled || !param)
2118 return -EINVAL;
2119
2120 system = strsep(&param, ":");
2121 if (!param)
2122 return -EINVAL;
2123
2124 event = strsep(&param, ":");
2125
2126 mutex_lock(&event_mutex);
2127
2128 ret = -EINVAL;
2129 file = find_event_file(tr, system, event);
2130 if (!file)
2131 goto out;
2132
2133 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2134
2135 if (enable)
2136 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2137 else
2138 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2139
2140 if (glob[0] == '!') {
2141 unregister_ftrace_function_probe_func(glob+1, ops);
2142 ret = 0;
2143 goto out;
2144 }
2145
2146 ret = -ENOMEM;
2147 data = kzalloc(sizeof(*data), GFP_KERNEL);
2148 if (!data)
2149 goto out;
2150
2151 data->enable = enable;
2152 data->count = -1;
2153 data->file = file;
2154
2155 if (!param)
2156 goto out_reg;
2157
2158 number = strsep(&param, ":");
2159
2160 ret = -EINVAL;
2161 if (!strlen(number))
2162 goto out_free;
2163
2164 /*
2165 * We use the callback data field (which is a pointer)
2166 * as our counter.
2167 */
2168 ret = kstrtoul(number, 0, &data->count);
2169 if (ret)
2170 goto out_free;
2171
2172 out_reg:
2173 /* Don't let event modules unload while probe registered */
2174 ret = try_module_get(file->event_call->mod);
2175 if (!ret) {
2176 ret = -EBUSY;
2177 goto out_free;
2178 }
2179
2180 ret = __ftrace_event_enable_disable(file, 1, 1);
2181 if (ret < 0)
2182 goto out_put;
2183 ret = register_ftrace_function_probe(glob, ops, data);
2184 /*
2185 * The above returns on success the # of functions enabled,
2186 * but if it didn't find any functions it returns zero.
2187 * Consider no functions a failure too.
2188 */
2189 if (!ret) {
2190 ret = -ENOENT;
2191 goto out_disable;
2192 } else if (ret < 0)
2193 goto out_disable;
2194 /* Just return zero, not the number of enabled functions */
2195 ret = 0;
2196 out:
2197 mutex_unlock(&event_mutex);
2198 return ret;
2199
2200 out_disable:
2201 __ftrace_event_enable_disable(file, 0, 1);
2202 out_put:
2203 module_put(file->event_call->mod);
2204 out_free:
2205 kfree(data);
2206 goto out;
2207 }
2208
2209 static struct ftrace_func_command event_enable_cmd = {
2210 .name = ENABLE_EVENT_STR,
2211 .func = event_enable_func,
2212 };
2213
2214 static struct ftrace_func_command event_disable_cmd = {
2215 .name = DISABLE_EVENT_STR,
2216 .func = event_enable_func,
2217 };
2218
2219 static __init int register_event_cmds(void)
2220 {
2221 int ret;
2222
2223 ret = register_ftrace_command(&event_enable_cmd);
2224 if (WARN_ON(ret < 0))
2225 return ret;
2226 ret = register_ftrace_command(&event_disable_cmd);
2227 if (WARN_ON(ret < 0))
2228 unregister_ftrace_command(&event_enable_cmd);
2229 return ret;
2230 }
2231 #else
2232 static inline int register_event_cmds(void) { return 0; }
2233 #endif /* CONFIG_DYNAMIC_FTRACE */
2234
2235 /*
2236 * The top level array has already had its ftrace_event_file
2237 * descriptors created in order to allow for early events to
2238 * be recorded. This function is called after the debugfs has been
2239 * initialized, and we now have to create the files associated
2240 * to the events.
2241 */
2242 static __init void
2243 __trace_early_add_event_dirs(struct trace_array *tr)
2244 {
2245 struct ftrace_event_file *file;
2246 int ret;
2247
2248
2249 list_for_each_entry(file, &tr->events, list) {
2250 ret = event_create_dir(tr->event_dir, file,
2251 &ftrace_event_id_fops,
2252 &ftrace_enable_fops,
2253 &ftrace_event_filter_fops,
2254 &ftrace_event_format_fops);
2255 if (ret < 0)
2256 pr_warning("Could not create directory for event %s\n",
2257 file->event_call->name);
2258 }
2259 }
2260
2261 /*
2262 * For early boot up, the top trace array requires to have
2263 * a list of events that can be enabled. This must be done before
2264 * the filesystem is set up in order to allow events to be traced
2265 * early.
2266 */
2267 static __init void
2268 __trace_early_add_events(struct trace_array *tr)
2269 {
2270 struct ftrace_event_call *call;
2271 int ret;
2272
2273 list_for_each_entry(call, &ftrace_events, list) {
2274 /* Early boot up should not have any modules loaded */
2275 if (WARN_ON_ONCE(call->mod))
2276 continue;
2277
2278 ret = __trace_early_add_new_event(call, tr);
2279 if (ret < 0)
2280 pr_warning("Could not create early event %s\n",
2281 call->name);
2282 }
2283 }
2284
2285 /* Remove the event directory structure for a trace directory. */
2286 static void
2287 __trace_remove_event_dirs(struct trace_array *tr)
2288 {
2289 struct ftrace_event_file *file, *next;
2290
2291 list_for_each_entry_safe(file, next, &tr->events, list) {
2292 list_del(&file->list);
2293 debugfs_remove_recursive(file->dir);
2294 remove_subsystem(file->system);
2295 kmem_cache_free(file_cachep, file);
2296 }
2297 }
2298
2299 static void
2300 __add_event_to_tracers(struct ftrace_event_call *call,
2301 struct ftrace_module_file_ops *file_ops)
2302 {
2303 struct trace_array *tr;
2304
2305 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2306 if (file_ops)
2307 __trace_add_new_mod_event(call, tr, file_ops);
2308 else
2309 __trace_add_new_event(call, tr,
2310 &ftrace_event_id_fops,
2311 &ftrace_enable_fops,
2312 &ftrace_event_filter_fops,
2313 &ftrace_event_format_fops);
2314 }
2315 }
2316
2317 static struct notifier_block trace_module_nb = {
2318 .notifier_call = trace_module_notify,
2319 .priority = 0,
2320 };
2321
2322 extern struct ftrace_event_call *__start_ftrace_events[];
2323 extern struct ftrace_event_call *__stop_ftrace_events[];
2324
2325 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2326
2327 static __init int setup_trace_event(char *str)
2328 {
2329 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2330 ring_buffer_expanded = true;
2331 tracing_selftest_disabled = true;
2332
2333 return 1;
2334 }
2335 __setup("trace_event=", setup_trace_event);
2336
2337 /* Expects to have event_mutex held when called */
2338 static int
2339 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2340 {
2341 struct dentry *d_events;
2342 struct dentry *entry;
2343
2344 entry = debugfs_create_file("set_event", 0644, parent,
2345 tr, &ftrace_set_event_fops);
2346 if (!entry) {
2347 pr_warning("Could not create debugfs 'set_event' entry\n");
2348 return -ENOMEM;
2349 }
2350
2351 d_events = debugfs_create_dir("events", parent);
2352 if (!d_events) {
2353 pr_warning("Could not create debugfs 'events' directory\n");
2354 return -ENOMEM;
2355 }
2356
2357 /* ring buffer internal formats */
2358 trace_create_file("header_page", 0444, d_events,
2359 ring_buffer_print_page_header,
2360 &ftrace_show_header_fops);
2361
2362 trace_create_file("header_event", 0444, d_events,
2363 ring_buffer_print_entry_header,
2364 &ftrace_show_header_fops);
2365
2366 trace_create_file("enable", 0644, d_events,
2367 tr, &ftrace_tr_enable_fops);
2368
2369 tr->event_dir = d_events;
2370
2371 return 0;
2372 }
2373
2374 /**
2375 * event_trace_add_tracer - add a instance of a trace_array to events
2376 * @parent: The parent dentry to place the files/directories for events in
2377 * @tr: The trace array associated with these events
2378 *
2379 * When a new instance is created, it needs to set up its events
2380 * directory, as well as other files associated with events. It also
2381 * creates the event hierachry in the @parent/events directory.
2382 *
2383 * Returns 0 on success.
2384 */
2385 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2386 {
2387 int ret;
2388
2389 mutex_lock(&event_mutex);
2390
2391 ret = create_event_toplevel_files(parent, tr);
2392 if (ret)
2393 goto out_unlock;
2394
2395 down_write(&trace_event_sem);
2396 __trace_add_event_dirs(tr);
2397 up_write(&trace_event_sem);
2398
2399 out_unlock:
2400 mutex_unlock(&event_mutex);
2401
2402 return ret;
2403 }
2404
2405 /*
2406 * The top trace array already had its file descriptors created.
2407 * Now the files themselves need to be created.
2408 */
2409 static __init int
2410 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2411 {
2412 int ret;
2413
2414 mutex_lock(&event_mutex);
2415
2416 ret = create_event_toplevel_files(parent, tr);
2417 if (ret)
2418 goto out_unlock;
2419
2420 down_write(&trace_event_sem);
2421 __trace_early_add_event_dirs(tr);
2422 up_write(&trace_event_sem);
2423
2424 out_unlock:
2425 mutex_unlock(&event_mutex);
2426
2427 return ret;
2428 }
2429
2430 int event_trace_del_tracer(struct trace_array *tr)
2431 {
2432 mutex_lock(&event_mutex);
2433
2434 /* Disable any running events */
2435 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
2436
2437 down_write(&trace_event_sem);
2438 __trace_remove_event_dirs(tr);
2439 debugfs_remove_recursive(tr->event_dir);
2440 up_write(&trace_event_sem);
2441
2442 tr->event_dir = NULL;
2443
2444 mutex_unlock(&event_mutex);
2445
2446 return 0;
2447 }
2448
2449 static __init int event_trace_memsetup(void)
2450 {
2451 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
2452 file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC);
2453 return 0;
2454 }
2455
2456 static __init int event_trace_enable(void)
2457 {
2458 struct trace_array *tr = top_trace_array();
2459 struct ftrace_event_call **iter, *call;
2460 char *buf = bootup_event_buf;
2461 char *token;
2462 int ret;
2463
2464 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
2465
2466 call = *iter;
2467 ret = event_init(call);
2468 if (!ret)
2469 list_add(&call->list, &ftrace_events);
2470 }
2471
2472 /*
2473 * We need the top trace array to have a working set of trace
2474 * points at early init, before the debug files and directories
2475 * are created. Create the file entries now, and attach them
2476 * to the actual file dentries later.
2477 */
2478 __trace_early_add_events(tr);
2479
2480 while (true) {
2481 token = strsep(&buf, ",");
2482
2483 if (!token)
2484 break;
2485 if (!*token)
2486 continue;
2487
2488 ret = ftrace_set_clr_event(tr, token, 1);
2489 if (ret)
2490 pr_warn("Failed to enable trace event: %s\n", token);
2491 }
2492
2493 trace_printk_start_comm();
2494
2495 register_event_cmds();
2496
2497 return 0;
2498 }
2499
2500 static __init int event_trace_init(void)
2501 {
2502 struct trace_array *tr;
2503 struct dentry *d_tracer;
2504 struct dentry *entry;
2505 int ret;
2506
2507 tr = top_trace_array();
2508
2509 d_tracer = tracing_init_dentry();
2510 if (!d_tracer)
2511 return 0;
2512
2513 entry = debugfs_create_file("available_events", 0444, d_tracer,
2514 tr, &ftrace_avail_fops);
2515 if (!entry)
2516 pr_warning("Could not create debugfs "
2517 "'available_events' entry\n");
2518
2519 if (trace_define_common_fields())
2520 pr_warning("tracing: Failed to allocate common fields");
2521
2522 ret = early_event_add_tracer(d_tracer, tr);
2523 if (ret)
2524 return ret;
2525
2526 ret = register_module_notifier(&trace_module_nb);
2527 if (ret)
2528 pr_warning("Failed to register trace events module notifier\n");
2529
2530 return 0;
2531 }
2532 early_initcall(event_trace_memsetup);
2533 core_initcall(event_trace_enable);
2534 fs_initcall(event_trace_init);
2535
2536 #ifdef CONFIG_FTRACE_STARTUP_TEST
2537
2538 static DEFINE_SPINLOCK(test_spinlock);
2539 static DEFINE_SPINLOCK(test_spinlock_irq);
2540 static DEFINE_MUTEX(test_mutex);
2541
2542 static __init void test_work(struct work_struct *dummy)
2543 {
2544 spin_lock(&test_spinlock);
2545 spin_lock_irq(&test_spinlock_irq);
2546 udelay(1);
2547 spin_unlock_irq(&test_spinlock_irq);
2548 spin_unlock(&test_spinlock);
2549
2550 mutex_lock(&test_mutex);
2551 msleep(1);
2552 mutex_unlock(&test_mutex);
2553 }
2554
2555 static __init int event_test_thread(void *unused)
2556 {
2557 void *test_malloc;
2558
2559 test_malloc = kmalloc(1234, GFP_KERNEL);
2560 if (!test_malloc)
2561 pr_info("failed to kmalloc\n");
2562
2563 schedule_on_each_cpu(test_work);
2564
2565 kfree(test_malloc);
2566
2567 set_current_state(TASK_INTERRUPTIBLE);
2568 while (!kthread_should_stop())
2569 schedule();
2570
2571 return 0;
2572 }
2573
2574 /*
2575 * Do various things that may trigger events.
2576 */
2577 static __init void event_test_stuff(void)
2578 {
2579 struct task_struct *test_thread;
2580
2581 test_thread = kthread_run(event_test_thread, NULL, "test-events");
2582 msleep(1);
2583 kthread_stop(test_thread);
2584 }
2585
2586 /*
2587 * For every trace event defined, we will test each trace point separately,
2588 * and then by groups, and finally all trace points.
2589 */
2590 static __init void event_trace_self_tests(void)
2591 {
2592 struct ftrace_subsystem_dir *dir;
2593 struct ftrace_event_file *file;
2594 struct ftrace_event_call *call;
2595 struct event_subsystem *system;
2596 struct trace_array *tr;
2597 int ret;
2598
2599 tr = top_trace_array();
2600
2601 pr_info("Running tests on trace events:\n");
2602
2603 list_for_each_entry(file, &tr->events, list) {
2604
2605 call = file->event_call;
2606
2607 /* Only test those that have a probe */
2608 if (!call->class || !call->class->probe)
2609 continue;
2610
2611 /*
2612 * Testing syscall events here is pretty useless, but
2613 * we still do it if configured. But this is time consuming.
2614 * What we really need is a user thread to perform the
2615 * syscalls as we test.
2616 */
2617 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
2618 if (call->class->system &&
2619 strcmp(call->class->system, "syscalls") == 0)
2620 continue;
2621 #endif
2622
2623 pr_info("Testing event %s: ", call->name);
2624
2625 /*
2626 * If an event is already enabled, someone is using
2627 * it and the self test should not be on.
2628 */
2629 if (file->flags & FTRACE_EVENT_FL_ENABLED) {
2630 pr_warning("Enabled event during self test!\n");
2631 WARN_ON_ONCE(1);
2632 continue;
2633 }
2634
2635 ftrace_event_enable_disable(file, 1);
2636 event_test_stuff();
2637 ftrace_event_enable_disable(file, 0);
2638
2639 pr_cont("OK\n");
2640 }
2641
2642 /* Now test at the sub system level */
2643
2644 pr_info("Running tests on trace event systems:\n");
2645
2646 list_for_each_entry(dir, &tr->systems, list) {
2647
2648 system = dir->subsystem;
2649
2650 /* the ftrace system is special, skip it */
2651 if (strcmp(system->name, "ftrace") == 0)
2652 continue;
2653
2654 pr_info("Testing event system %s: ", system->name);
2655
2656 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
2657 if (WARN_ON_ONCE(ret)) {
2658 pr_warning("error enabling system %s\n",
2659 system->name);
2660 continue;
2661 }
2662
2663 event_test_stuff();
2664
2665 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
2666 if (WARN_ON_ONCE(ret)) {
2667 pr_warning("error disabling system %s\n",
2668 system->name);
2669 continue;
2670 }
2671
2672 pr_cont("OK\n");
2673 }
2674
2675 /* Test with all events enabled */
2676
2677 pr_info("Running tests on all trace events:\n");
2678 pr_info("Testing all events: ");
2679
2680 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
2681 if (WARN_ON_ONCE(ret)) {
2682 pr_warning("error enabling all events\n");
2683 return;
2684 }
2685
2686 event_test_stuff();
2687
2688 /* reset sysname */
2689 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
2690 if (WARN_ON_ONCE(ret)) {
2691 pr_warning("error disabling all events\n");
2692 return;
2693 }
2694
2695 pr_cont("OK\n");
2696 }
2697
2698 #ifdef CONFIG_FUNCTION_TRACER
2699
2700 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
2701
2702 static void
2703 function_test_events_call(unsigned long ip, unsigned long parent_ip,
2704 struct ftrace_ops *op, struct pt_regs *pt_regs)
2705 {
2706 struct ring_buffer_event *event;
2707 struct ring_buffer *buffer;
2708 struct ftrace_entry *entry;
2709 unsigned long flags;
2710 long disabled;
2711 int cpu;
2712 int pc;
2713
2714 pc = preempt_count();
2715 preempt_disable_notrace();
2716 cpu = raw_smp_processor_id();
2717 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
2718
2719 if (disabled != 1)
2720 goto out;
2721
2722 local_save_flags(flags);
2723
2724 event = trace_current_buffer_lock_reserve(&buffer,
2725 TRACE_FN, sizeof(*entry),
2726 flags, pc);
2727 if (!event)
2728 goto out;
2729 entry = ring_buffer_event_data(event);
2730 entry->ip = ip;
2731 entry->parent_ip = parent_ip;
2732
2733 trace_buffer_unlock_commit(buffer, event, flags, pc);
2734
2735 out:
2736 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
2737 preempt_enable_notrace();
2738 }
2739
2740 static struct ftrace_ops trace_ops __initdata =
2741 {
2742 .func = function_test_events_call,
2743 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
2744 };
2745
2746 static __init void event_trace_self_test_with_function(void)
2747 {
2748 int ret;
2749 ret = register_ftrace_function(&trace_ops);
2750 if (WARN_ON(ret < 0)) {
2751 pr_info("Failed to enable function tracer for event tests\n");
2752 return;
2753 }
2754 pr_info("Running tests again, along with the function tracer\n");
2755 event_trace_self_tests();
2756 unregister_ftrace_function(&trace_ops);
2757 }
2758 #else
2759 static __init void event_trace_self_test_with_function(void)
2760 {
2761 }
2762 #endif
2763
2764 static __init int event_trace_self_tests_init(void)
2765 {
2766 if (!tracing_selftest_disabled) {
2767 event_trace_self_tests();
2768 event_trace_self_test_with_function();
2769 }
2770
2771 return 0;
2772 }
2773
2774 late_initcall(event_trace_self_tests_init);
2775
2776 #endif
ubuntu-bionic-kernel mirror