1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * event tracer
4 *
5 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
6 *
7 * - Added format output of fields of the trace point.
8 * This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
9 *
10 */
11
12 #define pr_fmt(fmt) fmt
13
14 #include <linux/workqueue.h>
15 #include <linux/security.h>
16 #include <linux/spinlock.h>
17 #include <linux/kthread.h>
18 #include <linux/tracefs.h>
19 #include <linux/uaccess.h>
20 #include <linux/module.h>
21 #include <linux/ctype.h>
22 #include <linux/sort.h>
23 #include <linux/slab.h>
24 #include <linux/delay.h>
25
26 #include <trace/events/sched.h>
27 #include <trace/syscall.h>
28
29 #include <asm/setup.h>
30
31 #include "trace_output.h"
32
33 #undef TRACE_SYSTEM
34 #define TRACE_SYSTEM "TRACE_SYSTEM"
35
36 DEFINE_MUTEX(event_mutex);
37
38 LIST_HEAD(ftrace_events);
39 static LIST_HEAD(ftrace_generic_fields);
40 static LIST_HEAD(ftrace_common_fields);
41 static bool eventdir_initialized;
42
43 static LIST_HEAD(module_strings);
44
45 struct module_string {
46 struct list_head next;
47 struct module *module;
48 char *str;
49 };
50
51 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
52
53 static struct kmem_cache *field_cachep;
54 static struct kmem_cache *file_cachep;
55
system_refcount(struct event_subsystem * system)56 static inline int system_refcount(struct event_subsystem *system)
57 {
58 return system->ref_count;
59 }
60
system_refcount_inc(struct event_subsystem * system)61 static int system_refcount_inc(struct event_subsystem *system)
62 {
63 return system->ref_count++;
64 }
65
system_refcount_dec(struct event_subsystem * system)66 static int system_refcount_dec(struct event_subsystem *system)
67 {
68 return --system->ref_count;
69 }
70
71 /* Double loops, do not use break, only goto's work */
72 #define do_for_each_event_file(tr, file) \
73 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
74 list_for_each_entry(file, &tr->events, list)
75
76 #define do_for_each_event_file_safe(tr, file) \
77 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
78 struct trace_event_file *___n; \
79 list_for_each_entry_safe(file, ___n, &tr->events, list)
80
81 #define while_for_each_event_file() \
82 }
83
84 static struct ftrace_event_field *
__find_event_field(struct list_head * head,char * name)85 __find_event_field(struct list_head *head, char *name)
86 {
87 struct ftrace_event_field *field;
88
89 list_for_each_entry(field, head, link) {
90 if (!strcmp(field->name, name))
91 return field;
92 }
93
94 return NULL;
95 }
96
97 struct ftrace_event_field *
trace_find_event_field(struct trace_event_call * call,char * name)98 trace_find_event_field(struct trace_event_call *call, char *name)
99 {
100 struct ftrace_event_field *field;
101 struct list_head *head;
102
103 head = trace_get_fields(call);
104 field = __find_event_field(head, name);
105 if (field)
106 return field;
107
108 field = __find_event_field(&ftrace_generic_fields, name);
109 if (field)
110 return field;
111
112 return __find_event_field(&ftrace_common_fields, name);
113 }
114
__trace_define_field(struct list_head * head,const char * type,const char * name,int offset,int size,int is_signed,int filter_type,int len)115 static int __trace_define_field(struct list_head *head, const char *type,
116 const char *name, int offset, int size,
117 int is_signed, int filter_type, int len)
118 {
119 struct ftrace_event_field *field;
120
121 field = kmem_cache_alloc(field_cachep, GFP_TRACE);
122 if (!field)
123 return -ENOMEM;
124
125 field->name = name;
126 field->type = type;
127
128 if (filter_type == FILTER_OTHER)
129 field->filter_type = filter_assign_type(type);
130 else
131 field->filter_type = filter_type;
132
133 field->offset = offset;
134 field->size = size;
135 field->is_signed = is_signed;
136 field->len = len;
137
138 list_add(&field->link, head);
139
140 return 0;
141 }
142
trace_define_field(struct trace_event_call * call,const char * type,const char * name,int offset,int size,int is_signed,int filter_type)143 int trace_define_field(struct trace_event_call *call, const char *type,
144 const char *name, int offset, int size, int is_signed,
145 int filter_type)
146 {
147 struct list_head *head;
148
149 if (WARN_ON(!call->class))
150 return 0;
151
152 head = trace_get_fields(call);
153 return __trace_define_field(head, type, name, offset, size,
154 is_signed, filter_type, 0);
155 }
156 EXPORT_SYMBOL_GPL(trace_define_field);
157
trace_define_field_ext(struct trace_event_call * call,const char * type,const char * name,int offset,int size,int is_signed,int filter_type,int len)158 static int trace_define_field_ext(struct trace_event_call *call, const char *type,
159 const char *name, int offset, int size, int is_signed,
160 int filter_type, int len)
161 {
162 struct list_head *head;
163
164 if (WARN_ON(!call->class))
165 return 0;
166
167 head = trace_get_fields(call);
168 return __trace_define_field(head, type, name, offset, size,
169 is_signed, filter_type, len);
170 }
171
172 #define __generic_field(type, item, filter_type) \
173 ret = __trace_define_field(&ftrace_generic_fields, #type, \
174 #item, 0, 0, is_signed_type(type), \
175 filter_type, 0); \
176 if (ret) \
177 return ret;
178
179 #define __common_field(type, item) \
180 ret = __trace_define_field(&ftrace_common_fields, #type, \
181 "common_" #item, \
182 offsetof(typeof(ent), item), \
183 sizeof(ent.item), \
184 is_signed_type(type), FILTER_OTHER, 0); \
185 if (ret) \
186 return ret;
187
trace_define_generic_fields(void)188 static int trace_define_generic_fields(void)
189 {
190 int ret;
191
192 __generic_field(int, CPU, FILTER_CPU);
193 __generic_field(int, cpu, FILTER_CPU);
194 __generic_field(int, common_cpu, FILTER_CPU);
195 __generic_field(char *, COMM, FILTER_COMM);
196 __generic_field(char *, comm, FILTER_COMM);
197 __generic_field(char *, stacktrace, FILTER_STACKTRACE);
198 __generic_field(char *, STACKTRACE, FILTER_STACKTRACE);
199
200 return ret;
201 }
202
trace_define_common_fields(void)203 static int trace_define_common_fields(void)
204 {
205 int ret;
206 struct trace_entry ent;
207
208 __common_field(unsigned short, type);
209 __common_field(unsigned char, flags);
210 /* Holds both preempt_count and migrate_disable */
211 __common_field(unsigned char, preempt_count);
212 __common_field(int, pid);
213
214 return ret;
215 }
216
trace_destroy_fields(struct trace_event_call * call)217 static void trace_destroy_fields(struct trace_event_call *call)
218 {
219 struct ftrace_event_field *field, *next;
220 struct list_head *head;
221
222 head = trace_get_fields(call);
223 list_for_each_entry_safe(field, next, head, link) {
224 list_del(&field->link);
225 kmem_cache_free(field_cachep, field);
226 }
227 }
228
229 /*
230 * run-time version of trace_event_get_offsets_<call>() that returns the last
231 * accessible offset of trace fields excluding __dynamic_array bytes
232 */
trace_event_get_offsets(struct trace_event_call * call)233 int trace_event_get_offsets(struct trace_event_call *call)
234 {
235 struct ftrace_event_field *tail;
236 struct list_head *head;
237
238 head = trace_get_fields(call);
239 /*
240 * head->next points to the last field with the largest offset,
241 * since it was added last by trace_define_field()
242 */
243 tail = list_first_entry(head, struct ftrace_event_field, link);
244 return tail->offset + tail->size;
245 }
246
247 /*
248 * Check if the referenced field is an array and return true,
249 * as arrays are OK to dereference.
250 */
test_field(const char * fmt,struct trace_event_call * call)251 static bool test_field(const char *fmt, struct trace_event_call *call)
252 {
253 struct trace_event_fields *field = call->class->fields_array;
254 const char *array_descriptor;
255 const char *p = fmt;
256 int len;
257
258 if (!(len = str_has_prefix(fmt, "REC->")))
259 return false;
260 fmt += len;
261 for (p = fmt; *p; p++) {
262 if (!isalnum(*p) && *p != '_')
263 break;
264 }
265 len = p - fmt;
266
267 for (; field->type; field++) {
268 if (strncmp(field->name, fmt, len) ||
269 field->name[len])
270 continue;
271 array_descriptor = strchr(field->type, '[');
272 /* This is an array and is OK to dereference. */
273 return array_descriptor != NULL;
274 }
275 return false;
276 }
277
278 /*
279 * Examine the print fmt of the event looking for unsafe dereference
280 * pointers using %p* that could be recorded in the trace event and
281 * much later referenced after the pointer was freed. Dereferencing
282 * pointers are OK, if it is dereferenced into the event itself.
283 */
test_event_printk(struct trace_event_call * call)284 static void test_event_printk(struct trace_event_call *call)
285 {
286 u64 dereference_flags = 0;
287 bool first = true;
288 const char *fmt, *c, *r, *a;
289 int parens = 0;
290 char in_quote = 0;
291 int start_arg = 0;
292 int arg = 0;
293 int i;
294
295 fmt = call->print_fmt;
296
297 if (!fmt)
298 return;
299
300 for (i = 0; fmt[i]; i++) {
301 switch (fmt[i]) {
302 case '\\':
303 i++;
304 if (!fmt[i])
305 return;
306 continue;
307 case '"':
308 case '\'':
309 /*
310 * The print fmt starts with a string that
311 * is processed first to find %p* usage,
312 * then after the first string, the print fmt
313 * contains arguments that are used to check
314 * if the dereferenced %p* usage is safe.
315 */
316 if (first) {
317 if (fmt[i] == '\'')
318 continue;
319 if (in_quote) {
320 arg = 0;
321 first = false;
322 /*
323 * If there was no %p* uses
324 * the fmt is OK.
325 */
326 if (!dereference_flags)
327 return;
328 }
329 }
330 if (in_quote) {
331 if (in_quote == fmt[i])
332 in_quote = 0;
333 } else {
334 in_quote = fmt[i];
335 }
336 continue;
337 case '%':
338 if (!first || !in_quote)
339 continue;
340 i++;
341 if (!fmt[i])
342 return;
343 switch (fmt[i]) {
344 case '%':
345 continue;
346 case 'p':
347 /* Find dereferencing fields */
348 switch (fmt[i + 1]) {
349 case 'B': case 'R': case 'r':
350 case 'b': case 'M': case 'm':
351 case 'I': case 'i': case 'E':
352 case 'U': case 'V': case 'N':
353 case 'a': case 'd': case 'D':
354 case 'g': case 't': case 'C':
355 case 'O': case 'f':
356 if (WARN_ONCE(arg == 63,
357 "Too many args for event: %s",
358 trace_event_name(call)))
359 return;
360 dereference_flags |= 1ULL << arg;
361 }
362 break;
363 default:
364 {
365 bool star = false;
366 int j;
367
368 /* Increment arg if %*s exists. */
369 for (j = 0; fmt[i + j]; j++) {
370 if (isdigit(fmt[i + j]) ||
371 fmt[i + j] == '.')
372 continue;
373 if (fmt[i + j] == '*') {
374 star = true;
375 continue;
376 }
377 if ((fmt[i + j] == 's') && star)
378 arg++;
379 break;
380 }
381 break;
382 } /* default */
383
384 } /* switch */
385 arg++;
386 continue;
387 case '(':
388 if (in_quote)
389 continue;
390 parens++;
391 continue;
392 case ')':
393 if (in_quote)
394 continue;
395 parens--;
396 if (WARN_ONCE(parens < 0,
397 "Paren mismatch for event: %s\narg='%s'\n%*s",
398 trace_event_name(call),
399 fmt + start_arg,
400 (i - start_arg) + 5, "^"))
401 return;
402 continue;
403 case ',':
404 if (in_quote || parens)
405 continue;
406 i++;
407 while (isspace(fmt[i]))
408 i++;
409 start_arg = i;
410 if (!(dereference_flags & (1ULL << arg)))
411 goto next_arg;
412
413 /* Find the REC-> in the argument */
414 c = strchr(fmt + i, ',');
415 r = strstr(fmt + i, "REC->");
416 if (r && (!c || r < c)) {
417 /*
418 * Addresses of events on the buffer,
419 * or an array on the buffer is
420 * OK to dereference.
421 * There's ways to fool this, but
422 * this is to catch common mistakes,
423 * not malicious code.
424 */
425 a = strchr(fmt + i, '&');
426 if ((a && (a < r)) || test_field(r, call))
427 dereference_flags &= ~(1ULL << arg);
428 } else if ((r = strstr(fmt + i, "__get_dynamic_array(")) &&
429 (!c || r < c)) {
430 dereference_flags &= ~(1ULL << arg);
431 } else if ((r = strstr(fmt + i, "__get_sockaddr(")) &&
432 (!c || r < c)) {
433 dereference_flags &= ~(1ULL << arg);
434 }
435
436 next_arg:
437 i--;
438 arg++;
439 }
440 }
441
442 /*
443 * If you triggered the below warning, the trace event reported
444 * uses an unsafe dereference pointer %p*. As the data stored
445 * at the trace event time may no longer exist when the trace
446 * event is printed, dereferencing to the original source is
447 * unsafe. The source of the dereference must be copied into the
448 * event itself, and the dereference must access the copy instead.
449 */
450 if (WARN_ON_ONCE(dereference_flags)) {
451 arg = 1;
452 while (!(dereference_flags & 1)) {
453 dereference_flags >>= 1;
454 arg++;
455 }
456 pr_warn("event %s has unsafe dereference of argument %d\n",
457 trace_event_name(call), arg);
458 pr_warn("print_fmt: %s\n", fmt);
459 }
460 }
461
trace_event_raw_init(struct trace_event_call * call)462 int trace_event_raw_init(struct trace_event_call *call)
463 {
464 int id;
465
466 id = register_trace_event(&call->event);
467 if (!id)
468 return -ENODEV;
469
470 test_event_printk(call);
471
472 return 0;
473 }
474 EXPORT_SYMBOL_GPL(trace_event_raw_init);
475
trace_event_ignore_this_pid(struct trace_event_file * trace_file)476 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
477 {
478 struct trace_array *tr = trace_file->tr;
479 struct trace_array_cpu *data;
480 struct trace_pid_list *no_pid_list;
481 struct trace_pid_list *pid_list;
482
483 pid_list = rcu_dereference_raw(tr->filtered_pids);
484 no_pid_list = rcu_dereference_raw(tr->filtered_no_pids);
485
486 if (!pid_list && !no_pid_list)
487 return false;
488
489 data = this_cpu_ptr(tr->array_buffer.data);
490
491 return data->ignore_pid;
492 }
493 EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
494
trace_event_buffer_reserve(struct trace_event_buffer * fbuffer,struct trace_event_file * trace_file,unsigned long len)495 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
496 struct trace_event_file *trace_file,
497 unsigned long len)
498 {
499 struct trace_event_call *event_call = trace_file->event_call;
500
501 if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
502 trace_event_ignore_this_pid(trace_file))
503 return NULL;
504
505 /*
506 * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
507 * preemption (adding one to the preempt_count). Since we are
508 * interested in the preempt_count at the time the tracepoint was
509 * hit, we need to subtract one to offset the increment.
510 */
511 fbuffer->trace_ctx = tracing_gen_ctx_dec();
512 fbuffer->trace_file = trace_file;
513
514 fbuffer->event =
515 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
516 event_call->event.type, len,
517 fbuffer->trace_ctx);
518 if (!fbuffer->event)
519 return NULL;
520
521 fbuffer->regs = NULL;
522 fbuffer->entry = ring_buffer_event_data(fbuffer->event);
523 return fbuffer->entry;
524 }
525 EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
526
trace_event_reg(struct trace_event_call * call,enum trace_reg type,void * data)527 int trace_event_reg(struct trace_event_call *call,
528 enum trace_reg type, void *data)
529 {
530 struct trace_event_file *file = data;
531
532 WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
533 switch (type) {
534 case TRACE_REG_REGISTER:
535 return tracepoint_probe_register(call->tp,
536 call->class->probe,
537 file);
538 case TRACE_REG_UNREGISTER:
539 tracepoint_probe_unregister(call->tp,
540 call->class->probe,
541 file);
542 return 0;
543
544 #ifdef CONFIG_PERF_EVENTS
545 case TRACE_REG_PERF_REGISTER:
546 return tracepoint_probe_register(call->tp,
547 call->class->perf_probe,
548 call);
549 case TRACE_REG_PERF_UNREGISTER:
550 tracepoint_probe_unregister(call->tp,
551 call->class->perf_probe,
552 call);
553 return 0;
554 case TRACE_REG_PERF_OPEN:
555 case TRACE_REG_PERF_CLOSE:
556 case TRACE_REG_PERF_ADD:
557 case TRACE_REG_PERF_DEL:
558 return 0;
559 #endif
560 }
561 return 0;
562 }
563 EXPORT_SYMBOL_GPL(trace_event_reg);
564
trace_event_enable_cmd_record(bool enable)565 void trace_event_enable_cmd_record(bool enable)
566 {
567 struct trace_event_file *file;
568 struct trace_array *tr;
569
570 lockdep_assert_held(&event_mutex);
571
572 do_for_each_event_file(tr, file) {
573
574 if (!(file->flags & EVENT_FILE_FL_ENABLED))
575 continue;
576
577 if (enable) {
578 tracing_start_cmdline_record();
579 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
580 } else {
581 tracing_stop_cmdline_record();
582 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
583 }
584 } while_for_each_event_file();
585 }
586
trace_event_enable_tgid_record(bool enable)587 void trace_event_enable_tgid_record(bool enable)
588 {
589 struct trace_event_file *file;
590 struct trace_array *tr;
591
592 lockdep_assert_held(&event_mutex);
593
594 do_for_each_event_file(tr, file) {
595 if (!(file->flags & EVENT_FILE_FL_ENABLED))
596 continue;
597
598 if (enable) {
599 tracing_start_tgid_record();
600 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
601 } else {
602 tracing_stop_tgid_record();
603 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
604 &file->flags);
605 }
606 } while_for_each_event_file();
607 }
608
__ftrace_event_enable_disable(struct trace_event_file * file,int enable,int soft_disable)609 static int __ftrace_event_enable_disable(struct trace_event_file *file,
610 int enable, int soft_disable)
611 {
612 struct trace_event_call *call = file->event_call;
613 struct trace_array *tr = file->tr;
614 int ret = 0;
615 int disable;
616
617 switch (enable) {
618 case 0:
619 /*
620 * When soft_disable is set and enable is cleared, the sm_ref
621 * reference counter is decremented. If it reaches 0, we want
622 * to clear the SOFT_DISABLED flag but leave the event in the
623 * state that it was. That is, if the event was enabled and
624 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
625 * is set we do not want the event to be enabled before we
626 * clear the bit.
627 *
628 * When soft_disable is not set but the SOFT_MODE flag is,
629 * we do nothing. Do not disable the tracepoint, otherwise
630 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
631 */
632 if (soft_disable) {
633 if (atomic_dec_return(&file->sm_ref) > 0)
634 break;
635 disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
636 clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
637 /* Disable use of trace_buffered_event */
638 trace_buffered_event_disable();
639 } else
640 disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
641
642 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
643 clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
644 if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
645 tracing_stop_cmdline_record();
646 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
647 }
648
649 if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
650 tracing_stop_tgid_record();
651 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
652 }
653
654 call->class->reg(call, TRACE_REG_UNREGISTER, file);
655 }
656 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
657 if (file->flags & EVENT_FILE_FL_SOFT_MODE)
658 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
659 else
660 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
661 break;
662 case 1:
663 /*
664 * When soft_disable is set and enable is set, we want to
665 * register the tracepoint for the event, but leave the event
666 * as is. That means, if the event was already enabled, we do
667 * nothing (but set SOFT_MODE). If the event is disabled, we
668 * set SOFT_DISABLED before enabling the event tracepoint, so
669 * it still seems to be disabled.
670 */
671 if (!soft_disable)
672 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
673 else {
674 if (atomic_inc_return(&file->sm_ref) > 1)
675 break;
676 set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
677 /* Enable use of trace_buffered_event */
678 trace_buffered_event_enable();
679 }
680
681 if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
682 bool cmd = false, tgid = false;
683
684 /* Keep the event disabled, when going to SOFT_MODE. */
685 if (soft_disable)
686 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
687
688 if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
689 cmd = true;
690 tracing_start_cmdline_record();
691 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
692 }
693
694 if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
695 tgid = true;
696 tracing_start_tgid_record();
697 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
698 }
699
700 ret = call->class->reg(call, TRACE_REG_REGISTER, file);
701 if (ret) {
702 if (cmd)
703 tracing_stop_cmdline_record();
704 if (tgid)
705 tracing_stop_tgid_record();
706 pr_info("event trace: Could not enable event "
707 "%s\n", trace_event_name(call));
708 break;
709 }
710 set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
711
712 /* WAS_ENABLED gets set but never cleared. */
713 set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
714 }
715 break;
716 }
717
718 return ret;
719 }
720
trace_event_enable_disable(struct trace_event_file * file,int enable,int soft_disable)721 int trace_event_enable_disable(struct trace_event_file *file,
722 int enable, int soft_disable)
723 {
724 return __ftrace_event_enable_disable(file, enable, soft_disable);
725 }
726
ftrace_event_enable_disable(struct trace_event_file * file,int enable)727 static int ftrace_event_enable_disable(struct trace_event_file *file,
728 int enable)
729 {
730 return __ftrace_event_enable_disable(file, enable, 0);
731 }
732
ftrace_clear_events(struct trace_array * tr)733 static void ftrace_clear_events(struct trace_array *tr)
734 {
735 struct trace_event_file *file;
736
737 mutex_lock(&event_mutex);
738 list_for_each_entry(file, &tr->events, list) {
739 ftrace_event_enable_disable(file, 0);
740 }
741 mutex_unlock(&event_mutex);
742 }
743
744 static void
event_filter_pid_sched_process_exit(void * data,struct task_struct * task)745 event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
746 {
747 struct trace_pid_list *pid_list;
748 struct trace_array *tr = data;
749
750 pid_list = rcu_dereference_raw(tr->filtered_pids);
751 trace_filter_add_remove_task(pid_list, NULL, task);
752
753 pid_list = rcu_dereference_raw(tr->filtered_no_pids);
754 trace_filter_add_remove_task(pid_list, NULL, task);
755 }
756
757 static void
event_filter_pid_sched_process_fork(void * data,struct task_struct * self,struct task_struct * task)758 event_filter_pid_sched_process_fork(void *data,
759 struct task_struct *self,
760 struct task_struct *task)
761 {
762 struct trace_pid_list *pid_list;
763 struct trace_array *tr = data;
764
765 pid_list = rcu_dereference_sched(tr->filtered_pids);
766 trace_filter_add_remove_task(pid_list, self, task);
767
768 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
769 trace_filter_add_remove_task(pid_list, self, task);
770 }
771
trace_event_follow_fork(struct trace_array * tr,bool enable)772 void trace_event_follow_fork(struct trace_array *tr, bool enable)
773 {
774 if (enable) {
775 register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
776 tr, INT_MIN);
777 register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
778 tr, INT_MAX);
779 } else {
780 unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
781 tr);
782 unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
783 tr);
784 }
785 }
786
787 static void
event_filter_pid_sched_switch_probe_pre(void * data,bool preempt,struct task_struct * prev,struct task_struct * next,unsigned int prev_state)788 event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
789 struct task_struct *prev,
790 struct task_struct *next,
791 unsigned int prev_state)
792 {
793 struct trace_array *tr = data;
794 struct trace_pid_list *no_pid_list;
795 struct trace_pid_list *pid_list;
796 bool ret;
797
798 pid_list = rcu_dereference_sched(tr->filtered_pids);
799 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
800
801 /*
802 * Sched switch is funny, as we only want to ignore it
803 * in the notrace case if both prev and next should be ignored.
804 */
805 ret = trace_ignore_this_task(NULL, no_pid_list, prev) &&
806 trace_ignore_this_task(NULL, no_pid_list, next);
807
808 this_cpu_write(tr->array_buffer.data->ignore_pid, ret ||
809 (trace_ignore_this_task(pid_list, NULL, prev) &&
810 trace_ignore_this_task(pid_list, NULL, next)));
811 }
812
813 static void
event_filter_pid_sched_switch_probe_post(void * data,bool preempt,struct task_struct * prev,struct task_struct * next,unsigned int prev_state)814 event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
815 struct task_struct *prev,
816 struct task_struct *next,
817 unsigned int prev_state)
818 {
819 struct trace_array *tr = data;
820 struct trace_pid_list *no_pid_list;
821 struct trace_pid_list *pid_list;
822
823 pid_list = rcu_dereference_sched(tr->filtered_pids);
824 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
825
826 this_cpu_write(tr->array_buffer.data->ignore_pid,
827 trace_ignore_this_task(pid_list, no_pid_list, next));
828 }
829
830 static void
event_filter_pid_sched_wakeup_probe_pre(void * data,struct task_struct * task)831 event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
832 {
833 struct trace_array *tr = data;
834 struct trace_pid_list *no_pid_list;
835 struct trace_pid_list *pid_list;
836
837 /* Nothing to do if we are already tracing */
838 if (!this_cpu_read(tr->array_buffer.data->ignore_pid))
839 return;
840
841 pid_list = rcu_dereference_sched(tr->filtered_pids);
842 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
843
844 this_cpu_write(tr->array_buffer.data->ignore_pid,
845 trace_ignore_this_task(pid_list, no_pid_list, task));
846 }
847
848 static void
event_filter_pid_sched_wakeup_probe_post(void * data,struct task_struct * task)849 event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
850 {
851 struct trace_array *tr = data;
852 struct trace_pid_list *no_pid_list;
853 struct trace_pid_list *pid_list;
854
855 /* Nothing to do if we are not tracing */
856 if (this_cpu_read(tr->array_buffer.data->ignore_pid))
857 return;
858
859 pid_list = rcu_dereference_sched(tr->filtered_pids);
860 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
861
862 /* Set tracing if current is enabled */
863 this_cpu_write(tr->array_buffer.data->ignore_pid,
864 trace_ignore_this_task(pid_list, no_pid_list, current));
865 }
866
unregister_pid_events(struct trace_array * tr)867 static void unregister_pid_events(struct trace_array *tr)
868 {
869 unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
870 unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
871
872 unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
873 unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
874
875 unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
876 unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
877
878 unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
879 unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
880 }
881
__ftrace_clear_event_pids(struct trace_array * tr,int type)882 static void __ftrace_clear_event_pids(struct trace_array *tr, int type)
883 {
884 struct trace_pid_list *pid_list;
885 struct trace_pid_list *no_pid_list;
886 struct trace_event_file *file;
887 int cpu;
888
889 pid_list = rcu_dereference_protected(tr->filtered_pids,
890 lockdep_is_held(&event_mutex));
891 no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
892 lockdep_is_held(&event_mutex));
893
894 /* Make sure there's something to do */
895 if (!pid_type_enabled(type, pid_list, no_pid_list))
896 return;
897
898 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
899 unregister_pid_events(tr);
900
901 list_for_each_entry(file, &tr->events, list) {
902 clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
903 }
904
905 for_each_possible_cpu(cpu)
906 per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
907 }
908
909 if (type & TRACE_PIDS)
910 rcu_assign_pointer(tr->filtered_pids, NULL);
911
912 if (type & TRACE_NO_PIDS)
913 rcu_assign_pointer(tr->filtered_no_pids, NULL);
914
915 /* Wait till all users are no longer using pid filtering */
916 tracepoint_synchronize_unregister();
917
918 if ((type & TRACE_PIDS) && pid_list)
919 trace_pid_list_free(pid_list);
920
921 if ((type & TRACE_NO_PIDS) && no_pid_list)
922 trace_pid_list_free(no_pid_list);
923 }
924
ftrace_clear_event_pids(struct trace_array * tr,int type)925 static void ftrace_clear_event_pids(struct trace_array *tr, int type)
926 {
927 mutex_lock(&event_mutex);
928 __ftrace_clear_event_pids(tr, type);
929 mutex_unlock(&event_mutex);
930 }
931
__put_system(struct event_subsystem * system)932 static void __put_system(struct event_subsystem *system)
933 {
934 struct event_filter *filter = system->filter;
935
936 WARN_ON_ONCE(system_refcount(system) == 0);
937 if (system_refcount_dec(system))
938 return;
939
940 list_del(&system->list);
941
942 if (filter) {
943 kfree(filter->filter_string);
944 kfree(filter);
945 }
946 kfree_const(system->name);
947 kfree(system);
948 }
949
__get_system(struct event_subsystem * system)950 static void __get_system(struct event_subsystem *system)
951 {
952 WARN_ON_ONCE(system_refcount(system) == 0);
953 system_refcount_inc(system);
954 }
955
__get_system_dir(struct trace_subsystem_dir * dir)956 static void __get_system_dir(struct trace_subsystem_dir *dir)
957 {
958 WARN_ON_ONCE(dir->ref_count == 0);
959 dir->ref_count++;
960 __get_system(dir->subsystem);
961 }
962
__put_system_dir(struct trace_subsystem_dir * dir)963 static void __put_system_dir(struct trace_subsystem_dir *dir)
964 {
965 WARN_ON_ONCE(dir->ref_count == 0);
966 /* If the subsystem is about to be freed, the dir must be too */
967 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
968
969 __put_system(dir->subsystem);
970 if (!--dir->ref_count)
971 kfree(dir);
972 }
973
put_system(struct trace_subsystem_dir * dir)974 static void put_system(struct trace_subsystem_dir *dir)
975 {
976 mutex_lock(&event_mutex);
977 __put_system_dir(dir);
978 mutex_unlock(&event_mutex);
979 }
980
remove_subsystem(struct trace_subsystem_dir * dir)981 static void remove_subsystem(struct trace_subsystem_dir *dir)
982 {
983 if (!dir)
984 return;
985
986 if (!--dir->nr_events) {
987 eventfs_remove_dir(dir->ei);
988 list_del(&dir->list);
989 __put_system_dir(dir);
990 }
991 }
992
event_file_get(struct trace_event_file * file)993 void event_file_get(struct trace_event_file *file)
994 {
995 atomic_inc(&file->ref);
996 }
997
event_file_put(struct trace_event_file * file)998 void event_file_put(struct trace_event_file *file)
999 {
1000 if (WARN_ON_ONCE(!atomic_read(&file->ref))) {
1001 if (file->flags & EVENT_FILE_FL_FREED)
1002 kmem_cache_free(file_cachep, file);
1003 return;
1004 }
1005
1006 if (atomic_dec_and_test(&file->ref)) {
1007 /* Count should only go to zero when it is freed */
1008 if (WARN_ON_ONCE(!(file->flags & EVENT_FILE_FL_FREED)))
1009 return;
1010 kmem_cache_free(file_cachep, file);
1011 }
1012 }
1013
remove_event_file_dir(struct trace_event_file * file)1014 static void remove_event_file_dir(struct trace_event_file *file)
1015 {
1016 eventfs_remove_dir(file->ei);
1017 list_del(&file->list);
1018 remove_subsystem(file->system);
1019 free_event_filter(file->filter);
1020 file->flags |= EVENT_FILE_FL_FREED;
1021 event_file_put(file);
1022 }
1023
1024 /*
1025 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
1026 */
1027 static int
__ftrace_set_clr_event_nolock(struct trace_array * tr,const char * match,const char * sub,const char * event,int set)1028 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
1029 const char *sub, const char *event, int set)
1030 {
1031 struct trace_event_file *file;
1032 struct trace_event_call *call;
1033 const char *name;
1034 int ret = -EINVAL;
1035 int eret = 0;
1036
1037 list_for_each_entry(file, &tr->events, list) {
1038
1039 call = file->event_call;
1040 name = trace_event_name(call);
1041
1042 if (!name || !call->class || !call->class->reg)
1043 continue;
1044
1045 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1046 continue;
1047
1048 if (match &&
1049 strcmp(match, name) != 0 &&
1050 strcmp(match, call->class->system) != 0)
1051 continue;
1052
1053 if (sub && strcmp(sub, call->class->system) != 0)
1054 continue;
1055
1056 if (event && strcmp(event, name) != 0)
1057 continue;
1058
1059 ret = ftrace_event_enable_disable(file, set);
1060
1061 /*
1062 * Save the first error and return that. Some events
1063 * may still have been enabled, but let the user
1064 * know that something went wrong.
1065 */
1066 if (ret && !eret)
1067 eret = ret;
1068
1069 ret = eret;
1070 }
1071
1072 return ret;
1073 }
1074
__ftrace_set_clr_event(struct trace_array * tr,const char * match,const char * sub,const char * event,int set)1075 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
1076 const char *sub, const char *event, int set)
1077 {
1078 int ret;
1079
1080 mutex_lock(&event_mutex);
1081 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
1082 mutex_unlock(&event_mutex);
1083
1084 return ret;
1085 }
1086
ftrace_set_clr_event(struct trace_array * tr,char * buf,int set)1087 int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
1088 {
1089 char *event = NULL, *sub = NULL, *match;
1090 int ret;
1091
1092 if (!tr)
1093 return -ENOENT;
1094 /*
1095 * The buf format can be <subsystem>:<event-name>
1096 * *:<event-name> means any event by that name.
1097 * :<event-name> is the same.
1098 *
1099 * <subsystem>:* means all events in that subsystem
1100 * <subsystem>: means the same.
1101 *
1102 * <name> (no ':') means all events in a subsystem with
1103 * the name <name> or any event that matches <name>
1104 */
1105
1106 match = strsep(&buf, ":");
1107 if (buf) {
1108 sub = match;
1109 event = buf;
1110 match = NULL;
1111
1112 if (!strlen(sub) || strcmp(sub, "*") == 0)
1113 sub = NULL;
1114 if (!strlen(event) || strcmp(event, "*") == 0)
1115 event = NULL;
1116 }
1117
1118 ret = __ftrace_set_clr_event(tr, match, sub, event, set);
1119
1120 /* Put back the colon to allow this to be called again */
1121 if (buf)
1122 *(buf - 1) = ':';
1123
1124 return ret;
1125 }
1126
1127 /**
1128 * trace_set_clr_event - enable or disable an event
1129 * @system: system name to match (NULL for any system)
1130 * @event: event name to match (NULL for all events, within system)
1131 * @set: 1 to enable, 0 to disable
1132 *
1133 * This is a way for other parts of the kernel to enable or disable
1134 * event recording.
1135 *
1136 * Returns 0 on success, -EINVAL if the parameters do not match any
1137 * registered events.
1138 */
trace_set_clr_event(const char * system,const char * event,int set)1139 int trace_set_clr_event(const char *system, const char *event, int set)
1140 {
1141 struct trace_array *tr = top_trace_array();
1142
1143 if (!tr)
1144 return -ENODEV;
1145
1146 return __ftrace_set_clr_event(tr, NULL, system, event, set);
1147 }
1148 EXPORT_SYMBOL_GPL(trace_set_clr_event);
1149
1150 /**
1151 * trace_array_set_clr_event - enable or disable an event for a trace array.
1152 * @tr: concerned trace array.
1153 * @system: system name to match (NULL for any system)
1154 * @event: event name to match (NULL for all events, within system)
1155 * @enable: true to enable, false to disable
1156 *
1157 * This is a way for other parts of the kernel to enable or disable
1158 * event recording.
1159 *
1160 * Returns 0 on success, -EINVAL if the parameters do not match any
1161 * registered events.
1162 */
trace_array_set_clr_event(struct trace_array * tr,const char * system,const char * event,bool enable)1163 int trace_array_set_clr_event(struct trace_array *tr, const char *system,
1164 const char *event, bool enable)
1165 {
1166 int set;
1167
1168 if (!tr)
1169 return -ENOENT;
1170
1171 set = (enable == true) ? 1 : 0;
1172 return __ftrace_set_clr_event(tr, NULL, system, event, set);
1173 }
1174 EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
1175
1176 /* 128 should be much more than enough */
1177 #define EVENT_BUF_SIZE 127
1178
1179 static ssize_t
ftrace_event_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)1180 ftrace_event_write(struct file *file, const char __user *ubuf,
1181 size_t cnt, loff_t *ppos)
1182 {
1183 struct trace_parser parser;
1184 struct seq_file *m = file->private_data;
1185 struct trace_array *tr = m->private;
1186 ssize_t read, ret;
1187
1188 if (!cnt)
1189 return 0;
1190
1191 ret = tracing_update_buffers();
1192 if (ret < 0)
1193 return ret;
1194
1195 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
1196 return -ENOMEM;
1197
1198 read = trace_get_user(&parser, ubuf, cnt, ppos);
1199
1200 if (read >= 0 && trace_parser_loaded((&parser))) {
1201 int set = 1;
1202
1203 if (*parser.buffer == '!')
1204 set = 0;
1205
1206 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
1207 if (ret)
1208 goto out_put;
1209 }
1210
1211 ret = read;
1212
1213 out_put:
1214 trace_parser_put(&parser);
1215
1216 return ret;
1217 }
1218
1219 static void *
t_next(struct seq_file * m,void * v,loff_t * pos)1220 t_next(struct seq_file *m, void *v, loff_t *pos)
1221 {
1222 struct trace_event_file *file = v;
1223 struct trace_event_call *call;
1224 struct trace_array *tr = m->private;
1225
1226 (*pos)++;
1227
1228 list_for_each_entry_continue(file, &tr->events, list) {
1229 call = file->event_call;
1230 /*
1231 * The ftrace subsystem is for showing formats only.
1232 * They can not be enabled or disabled via the event files.
1233 */
1234 if (call->class && call->class->reg &&
1235 !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1236 return file;
1237 }
1238
1239 return NULL;
1240 }
1241
t_start(struct seq_file * m,loff_t * pos)1242 static void *t_start(struct seq_file *m, loff_t *pos)
1243 {
1244 struct trace_event_file *file;
1245 struct trace_array *tr = m->private;
1246 loff_t l;
1247
1248 mutex_lock(&event_mutex);
1249
1250 file = list_entry(&tr->events, struct trace_event_file, list);
1251 for (l = 0; l <= *pos; ) {
1252 file = t_next(m, file, &l);
1253 if (!file)
1254 break;
1255 }
1256 return file;
1257 }
1258
1259 static void *
s_next(struct seq_file * m,void * v,loff_t * pos)1260 s_next(struct seq_file *m, void *v, loff_t *pos)
1261 {
1262 struct trace_event_file *file = v;
1263 struct trace_array *tr = m->private;
1264
1265 (*pos)++;
1266
1267 list_for_each_entry_continue(file, &tr->events, list) {
1268 if (file->flags & EVENT_FILE_FL_ENABLED)
1269 return file;
1270 }
1271
1272 return NULL;
1273 }
1274
s_start(struct seq_file * m,loff_t * pos)1275 static void *s_start(struct seq_file *m, loff_t *pos)
1276 {
1277 struct trace_event_file *file;
1278 struct trace_array *tr = m->private;
1279 loff_t l;
1280
1281 mutex_lock(&event_mutex);
1282
1283 file = list_entry(&tr->events, struct trace_event_file, list);
1284 for (l = 0; l <= *pos; ) {
1285 file = s_next(m, file, &l);
1286 if (!file)
1287 break;
1288 }
1289 return file;
1290 }
1291
t_show(struct seq_file * m,void * v)1292 static int t_show(struct seq_file *m, void *v)
1293 {
1294 struct trace_event_file *file = v;
1295 struct trace_event_call *call = file->event_call;
1296
1297 if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1298 seq_printf(m, "%s:", call->class->system);
1299 seq_printf(m, "%s\n", trace_event_name(call));
1300
1301 return 0;
1302 }
1303
t_stop(struct seq_file * m,void * p)1304 static void t_stop(struct seq_file *m, void *p)
1305 {
1306 mutex_unlock(&event_mutex);
1307 }
1308
1309 static void *
__next(struct seq_file * m,void * v,loff_t * pos,int type)1310 __next(struct seq_file *m, void *v, loff_t *pos, int type)
1311 {
1312 struct trace_array *tr = m->private;
1313 struct trace_pid_list *pid_list;
1314
1315 if (type == TRACE_PIDS)
1316 pid_list = rcu_dereference_sched(tr->filtered_pids);
1317 else
1318 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1319
1320 return trace_pid_next(pid_list, v, pos);
1321 }
1322
1323 static void *
p_next(struct seq_file * m,void * v,loff_t * pos)1324 p_next(struct seq_file *m, void *v, loff_t *pos)
1325 {
1326 return __next(m, v, pos, TRACE_PIDS);
1327 }
1328
1329 static void *
np_next(struct seq_file * m,void * v,loff_t * pos)1330 np_next(struct seq_file *m, void *v, loff_t *pos)
1331 {
1332 return __next(m, v, pos, TRACE_NO_PIDS);
1333 }
1334
__start(struct seq_file * m,loff_t * pos,int type)1335 static void *__start(struct seq_file *m, loff_t *pos, int type)
1336 __acquires(RCU)
1337 {
1338 struct trace_pid_list *pid_list;
1339 struct trace_array *tr = m->private;
1340
1341 /*
1342 * Grab the mutex, to keep calls to p_next() having the same
1343 * tr->filtered_pids as p_start() has.
1344 * If we just passed the tr->filtered_pids around, then RCU would
1345 * have been enough, but doing that makes things more complex.
1346 */
1347 mutex_lock(&event_mutex);
1348 rcu_read_lock_sched();
1349
1350 if (type == TRACE_PIDS)
1351 pid_list = rcu_dereference_sched(tr->filtered_pids);
1352 else
1353 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1354
1355 if (!pid_list)
1356 return NULL;
1357
1358 return trace_pid_start(pid_list, pos);
1359 }
1360
p_start(struct seq_file * m,loff_t * pos)1361 static void *p_start(struct seq_file *m, loff_t *pos)
1362 __acquires(RCU)
1363 {
1364 return __start(m, pos, TRACE_PIDS);
1365 }
1366
np_start(struct seq_file * m,loff_t * pos)1367 static void *np_start(struct seq_file *m, loff_t *pos)
1368 __acquires(RCU)
1369 {
1370 return __start(m, pos, TRACE_NO_PIDS);
1371 }
1372
p_stop(struct seq_file * m,void * p)1373 static void p_stop(struct seq_file *m, void *p)
1374 __releases(RCU)
1375 {
1376 rcu_read_unlock_sched();
1377 mutex_unlock(&event_mutex);
1378 }
1379
1380 static ssize_t
event_enable_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)1381 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1382 loff_t *ppos)
1383 {
1384 struct trace_event_file *file;
1385 unsigned long flags;
1386 char buf[4] = "0";
1387
1388 mutex_lock(&event_mutex);
1389 file = event_file_data(filp);
1390 if (likely(file))
1391 flags = file->flags;
1392 mutex_unlock(&event_mutex);
1393
1394 if (!file || flags & EVENT_FILE_FL_FREED)
1395 return -ENODEV;
1396
1397 if (flags & EVENT_FILE_FL_ENABLED &&
1398 !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1399 strcpy(buf, "1");
1400
1401 if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1402 flags & EVENT_FILE_FL_SOFT_MODE)
1403 strcat(buf, "*");
1404
1405 strcat(buf, "\n");
1406
1407 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1408 }
1409
1410 static ssize_t
event_enable_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)1411 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1412 loff_t *ppos)
1413 {
1414 struct trace_event_file *file;
1415 unsigned long val;
1416 int ret;
1417
1418 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1419 if (ret)
1420 return ret;
1421
1422 ret = tracing_update_buffers();
1423 if (ret < 0)
1424 return ret;
1425
1426 switch (val) {
1427 case 0:
1428 case 1:
1429 ret = -ENODEV;
1430 mutex_lock(&event_mutex);
1431 file = event_file_data(filp);
1432 if (likely(file && !(file->flags & EVENT_FILE_FL_FREED)))
1433 ret = ftrace_event_enable_disable(file, val);
1434 mutex_unlock(&event_mutex);
1435 break;
1436
1437 default:
1438 return -EINVAL;
1439 }
1440
1441 *ppos += cnt;
1442
1443 return ret ? ret : cnt;
1444 }
1445
1446 static ssize_t
system_enable_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)1447 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1448 loff_t *ppos)
1449 {
1450 const char set_to_char[4] = { '?', '0', '1', 'X' };
1451 struct trace_subsystem_dir *dir = filp->private_data;
1452 struct event_subsystem *system = dir->subsystem;
1453 struct trace_event_call *call;
1454 struct trace_event_file *file;
1455 struct trace_array *tr = dir->tr;
1456 char buf[2];
1457 int set = 0;
1458 int ret;
1459
1460 mutex_lock(&event_mutex);
1461 list_for_each_entry(file, &tr->events, list) {
1462 call = file->event_call;
1463 if ((call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
1464 !trace_event_name(call) || !call->class || !call->class->reg)
1465 continue;
1466
1467 if (system && strcmp(call->class->system, system->name) != 0)
1468 continue;
1469
1470 /*
1471 * We need to find out if all the events are set
1472 * or if all events or cleared, or if we have
1473 * a mixture.
1474 */
1475 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1476
1477 /*
1478 * If we have a mixture, no need to look further.
1479 */
1480 if (set == 3)
1481 break;
1482 }
1483 mutex_unlock(&event_mutex);
1484
1485 buf[0] = set_to_char[set];
1486 buf[1] = '\n';
1487
1488 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1489
1490 return ret;
1491 }
1492
1493 static ssize_t
system_enable_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)1494 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1495 loff_t *ppos)
1496 {
1497 struct trace_subsystem_dir *dir = filp->private_data;
1498 struct event_subsystem *system = dir->subsystem;
1499 const char *name = NULL;
1500 unsigned long val;
1501 ssize_t ret;
1502
1503 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1504 if (ret)
1505 return ret;
1506
1507 ret = tracing_update_buffers();
1508 if (ret < 0)
1509 return ret;
1510
1511 if (val != 0 && val != 1)
1512 return -EINVAL;
1513
1514 /*
1515 * Opening of "enable" adds a ref count to system,
1516 * so the name is safe to use.
1517 */
1518 if (system)
1519 name = system->name;
1520
1521 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1522 if (ret)
1523 goto out;
1524
1525 ret = cnt;
1526
1527 out:
1528 *ppos += cnt;
1529
1530 return ret;
1531 }
1532
1533 enum {
1534 FORMAT_HEADER = 1,
1535 FORMAT_FIELD_SEPERATOR = 2,
1536 FORMAT_PRINTFMT = 3,
1537 };
1538
f_next(struct seq_file * m,void * v,loff_t * pos)1539 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1540 {
1541 struct trace_event_call *call = event_file_data(m->private);
1542 struct list_head *common_head = &ftrace_common_fields;
1543 struct list_head *head = trace_get_fields(call);
1544 struct list_head *node = v;
1545
1546 (*pos)++;
1547
1548 switch ((unsigned long)v) {
1549 case FORMAT_HEADER:
1550 node = common_head;
1551 break;
1552
1553 case FORMAT_FIELD_SEPERATOR:
1554 node = head;
1555 break;
1556
1557 case FORMAT_PRINTFMT:
1558 /* all done */
1559 return NULL;
1560 }
1561
1562 node = node->prev;
1563 if (node == common_head)
1564 return (void *)FORMAT_FIELD_SEPERATOR;
1565 else if (node == head)
1566 return (void *)FORMAT_PRINTFMT;
1567 else
1568 return node;
1569 }
1570
f_show(struct seq_file * m,void * v)1571 static int f_show(struct seq_file *m, void *v)
1572 {
1573 struct trace_event_call *call = event_file_data(m->private);
1574 struct ftrace_event_field *field;
1575 const char *array_descriptor;
1576
1577 switch ((unsigned long)v) {
1578 case FORMAT_HEADER:
1579 seq_printf(m, "name: %s\n", trace_event_name(call));
1580 seq_printf(m, "ID: %d\n", call->event.type);
1581 seq_puts(m, "format:\n");
1582 return 0;
1583
1584 case FORMAT_FIELD_SEPERATOR:
1585 seq_putc(m, '\n');
1586 return 0;
1587
1588 case FORMAT_PRINTFMT:
1589 seq_printf(m, "\nprint fmt: %s\n",
1590 call->print_fmt);
1591 return 0;
1592 }
1593
1594 field = list_entry(v, struct ftrace_event_field, link);
1595 /*
1596 * Smartly shows the array type(except dynamic array).
1597 * Normal:
1598 * field:TYPE VAR
1599 * If TYPE := TYPE[LEN], it is shown:
1600 * field:TYPE VAR[LEN]
1601 */
1602 array_descriptor = strchr(field->type, '[');
1603
1604 if (str_has_prefix(field->type, "__data_loc"))
1605 array_descriptor = NULL;
1606
1607 if (!array_descriptor)
1608 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1609 field->type, field->name, field->offset,
1610 field->size, !!field->is_signed);
1611 else if (field->len)
1612 seq_printf(m, "\tfield:%.*s %s[%d];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1613 (int)(array_descriptor - field->type),
1614 field->type, field->name,
1615 field->len, field->offset,
1616 field->size, !!field->is_signed);
1617 else
1618 seq_printf(m, "\tfield:%.*s %s[];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1619 (int)(array_descriptor - field->type),
1620 field->type, field->name,
1621 field->offset, field->size, !!field->is_signed);
1622
1623 return 0;
1624 }
1625
f_start(struct seq_file * m,loff_t * pos)1626 static void *f_start(struct seq_file *m, loff_t *pos)
1627 {
1628 void *p = (void *)FORMAT_HEADER;
1629 loff_t l = 0;
1630
1631 /* ->stop() is called even if ->start() fails */
1632 mutex_lock(&event_mutex);
1633 if (!event_file_data(m->private))
1634 return ERR_PTR(-ENODEV);
1635
1636 while (l < *pos && p)
1637 p = f_next(m, p, &l);
1638
1639 return p;
1640 }
1641
f_stop(struct seq_file * m,void * p)1642 static void f_stop(struct seq_file *m, void *p)
1643 {
1644 mutex_unlock(&event_mutex);
1645 }
1646
1647 static const struct seq_operations trace_format_seq_ops = {
1648 .start = f_start,
1649 .next = f_next,
1650 .stop = f_stop,
1651 .show = f_show,
1652 };
1653
trace_format_open(struct inode * inode,struct file * file)1654 static int trace_format_open(struct inode *inode, struct file *file)
1655 {
1656 struct seq_file *m;
1657 int ret;
1658
1659 /* Do we want to hide event format files on tracefs lockdown? */
1660
1661 ret = seq_open(file, &trace_format_seq_ops);
1662 if (ret < 0)
1663 return ret;
1664
1665 m = file->private_data;
1666 m->private = file;
1667
1668 return 0;
1669 }
1670
1671 #ifdef CONFIG_PERF_EVENTS
1672 static ssize_t
event_id_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)1673 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1674 {
1675 int id = (long)event_file_data(filp);
1676 char buf[32];
1677 int len;
1678
1679 if (unlikely(!id))
1680 return -ENODEV;
1681
1682 len = sprintf(buf, "%d\n", id);
1683
1684 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1685 }
1686 #endif
1687
1688 static ssize_t
event_filter_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)1689 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1690 loff_t *ppos)
1691 {
1692 struct trace_event_file *file;
1693 struct trace_seq *s;
1694 int r = -ENODEV;
1695
1696 if (*ppos)
1697 return 0;
1698
1699 s = kmalloc(sizeof(*s), GFP_KERNEL);
1700
1701 if (!s)
1702 return -ENOMEM;
1703
1704 trace_seq_init(s);
1705
1706 mutex_lock(&event_mutex);
1707 file = event_file_data(filp);
1708 if (file && !(file->flags & EVENT_FILE_FL_FREED))
1709 print_event_filter(file, s);
1710 mutex_unlock(&event_mutex);
1711
1712 if (file)
1713 r = simple_read_from_buffer(ubuf, cnt, ppos,
1714 s->buffer, trace_seq_used(s));
1715
1716 kfree(s);
1717
1718 return r;
1719 }
1720
1721 static ssize_t
event_filter_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)1722 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1723 loff_t *ppos)
1724 {
1725 struct trace_event_file *file;
1726 char *buf;
1727 int err = -ENODEV;
1728
1729 if (cnt >= PAGE_SIZE)
1730 return -EINVAL;
1731
1732 buf = memdup_user_nul(ubuf, cnt);
1733 if (IS_ERR(buf))
1734 return PTR_ERR(buf);
1735
1736 mutex_lock(&event_mutex);
1737 file = event_file_data(filp);
1738 if (file)
1739 err = apply_event_filter(file, buf);
1740 mutex_unlock(&event_mutex);
1741
1742 kfree(buf);
1743 if (err < 0)
1744 return err;
1745
1746 *ppos += cnt;
1747
1748 return cnt;
1749 }
1750
1751 static LIST_HEAD(event_subsystems);
1752
subsystem_open(struct inode * inode,struct file * filp)1753 static int subsystem_open(struct inode *inode, struct file *filp)
1754 {
1755 struct trace_subsystem_dir *dir = NULL, *iter_dir;
1756 struct trace_array *tr = NULL, *iter_tr;
1757 struct event_subsystem *system = NULL;
1758 int ret;
1759
1760 if (tracing_is_disabled())
1761 return -ENODEV;
1762
1763 /* Make sure the system still exists */
1764 mutex_lock(&event_mutex);
1765 mutex_lock(&trace_types_lock);
1766 list_for_each_entry(iter_tr, &ftrace_trace_arrays, list) {
1767 list_for_each_entry(iter_dir, &iter_tr->systems, list) {
1768 if (iter_dir == inode->i_private) {
1769 /* Don't open systems with no events */
1770 tr = iter_tr;
1771 dir = iter_dir;
1772 if (dir->nr_events) {
1773 __get_system_dir(dir);
1774 system = dir->subsystem;
1775 }
1776 goto exit_loop;
1777 }
1778 }
1779 }
1780 exit_loop:
1781 mutex_unlock(&trace_types_lock);
1782 mutex_unlock(&event_mutex);
1783
1784 if (!system)
1785 return -ENODEV;
1786
1787 /* Still need to increment the ref count of the system */
1788 if (trace_array_get(tr) < 0) {
1789 put_system(dir);
1790 return -ENODEV;
1791 }
1792
1793 ret = tracing_open_generic(inode, filp);
1794 if (ret < 0) {
1795 trace_array_put(tr);
1796 put_system(dir);
1797 }
1798
1799 return ret;
1800 }
1801
system_tr_open(struct inode * inode,struct file * filp)1802 static int system_tr_open(struct inode *inode, struct file *filp)
1803 {
1804 struct trace_subsystem_dir *dir;
1805 struct trace_array *tr = inode->i_private;
1806 int ret;
1807
1808 /* Make a temporary dir that has no system but points to tr */
1809 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1810 if (!dir)
1811 return -ENOMEM;
1812
1813 ret = tracing_open_generic_tr(inode, filp);
1814 if (ret < 0) {
1815 kfree(dir);
1816 return ret;
1817 }
1818 dir->tr = tr;
1819 filp->private_data = dir;
1820
1821 return 0;
1822 }
1823
subsystem_release(struct inode * inode,struct file * file)1824 static int subsystem_release(struct inode *inode, struct file *file)
1825 {
1826 struct trace_subsystem_dir *dir = file->private_data;
1827
1828 trace_array_put(dir->tr);
1829
1830 /*
1831 * If dir->subsystem is NULL, then this is a temporary
1832 * descriptor that was made for a trace_array to enable
1833 * all subsystems.
1834 */
1835 if (dir->subsystem)
1836 put_system(dir);
1837 else
1838 kfree(dir);
1839
1840 return 0;
1841 }
1842
1843 static ssize_t
subsystem_filter_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)1844 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1845 loff_t *ppos)
1846 {
1847 struct trace_subsystem_dir *dir = filp->private_data;
1848 struct event_subsystem *system = dir->subsystem;
1849 struct trace_seq *s;
1850 int r;
1851
1852 if (*ppos)
1853 return 0;
1854
1855 s = kmalloc(sizeof(*s), GFP_KERNEL);
1856 if (!s)
1857 return -ENOMEM;
1858
1859 trace_seq_init(s);
1860
1861 print_subsystem_event_filter(system, s);
1862 r = simple_read_from_buffer(ubuf, cnt, ppos,
1863 s->buffer, trace_seq_used(s));
1864
1865 kfree(s);
1866
1867 return r;
1868 }
1869
1870 static ssize_t
subsystem_filter_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)1871 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1872 loff_t *ppos)
1873 {
1874 struct trace_subsystem_dir *dir = filp->private_data;
1875 char *buf;
1876 int err;
1877
1878 if (cnt >= PAGE_SIZE)
1879 return -EINVAL;
1880
1881 buf = memdup_user_nul(ubuf, cnt);
1882 if (IS_ERR(buf))
1883 return PTR_ERR(buf);
1884
1885 err = apply_subsystem_event_filter(dir, buf);
1886 kfree(buf);
1887 if (err < 0)
1888 return err;
1889
1890 *ppos += cnt;
1891
1892 return cnt;
1893 }
1894
1895 static ssize_t
show_header(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)1896 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1897 {
1898 int (*func)(struct trace_seq *s) = filp->private_data;
1899 struct trace_seq *s;
1900 int r;
1901
1902 if (*ppos)
1903 return 0;
1904
1905 s = kmalloc(sizeof(*s), GFP_KERNEL);
1906 if (!s)
1907 return -ENOMEM;
1908
1909 trace_seq_init(s);
1910
1911 func(s);
1912 r = simple_read_from_buffer(ubuf, cnt, ppos,
1913 s->buffer, trace_seq_used(s));
1914
1915 kfree(s);
1916
1917 return r;
1918 }
1919
ignore_task_cpu(void * data)1920 static void ignore_task_cpu(void *data)
1921 {
1922 struct trace_array *tr = data;
1923 struct trace_pid_list *pid_list;
1924 struct trace_pid_list *no_pid_list;
1925
1926 /*
1927 * This function is called by on_each_cpu() while the
1928 * event_mutex is held.
1929 */
1930 pid_list = rcu_dereference_protected(tr->filtered_pids,
1931 mutex_is_locked(&event_mutex));
1932 no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
1933 mutex_is_locked(&event_mutex));
1934
1935 this_cpu_write(tr->array_buffer.data->ignore_pid,
1936 trace_ignore_this_task(pid_list, no_pid_list, current));
1937 }
1938
register_pid_events(struct trace_array * tr)1939 static void register_pid_events(struct trace_array *tr)
1940 {
1941 /*
1942 * Register a probe that is called before all other probes
1943 * to set ignore_pid if next or prev do not match.
1944 * Register a probe this is called after all other probes
1945 * to only keep ignore_pid set if next pid matches.
1946 */
1947 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1948 tr, INT_MAX);
1949 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1950 tr, 0);
1951
1952 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1953 tr, INT_MAX);
1954 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1955 tr, 0);
1956
1957 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1958 tr, INT_MAX);
1959 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1960 tr, 0);
1961
1962 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1963 tr, INT_MAX);
1964 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1965 tr, 0);
1966 }
1967
1968 static ssize_t
event_pid_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos,int type)1969 event_pid_write(struct file *filp, const char __user *ubuf,
1970 size_t cnt, loff_t *ppos, int type)
1971 {
1972 struct seq_file *m = filp->private_data;
1973 struct trace_array *tr = m->private;
1974 struct trace_pid_list *filtered_pids = NULL;
1975 struct trace_pid_list *other_pids = NULL;
1976 struct trace_pid_list *pid_list;
1977 struct trace_event_file *file;
1978 ssize_t ret;
1979
1980 if (!cnt)
1981 return 0;
1982
1983 ret = tracing_update_buffers();
1984 if (ret < 0)
1985 return ret;
1986
1987 mutex_lock(&event_mutex);
1988
1989 if (type == TRACE_PIDS) {
1990 filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1991 lockdep_is_held(&event_mutex));
1992 other_pids = rcu_dereference_protected(tr->filtered_no_pids,
1993 lockdep_is_held(&event_mutex));
1994 } else {
1995 filtered_pids = rcu_dereference_protected(tr->filtered_no_pids,
1996 lockdep_is_held(&event_mutex));
1997 other_pids = rcu_dereference_protected(tr->filtered_pids,
1998 lockdep_is_held(&event_mutex));
1999 }
2000
2001 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
2002 if (ret < 0)
2003 goto out;
2004
2005 if (type == TRACE_PIDS)
2006 rcu_assign_pointer(tr->filtered_pids, pid_list);
2007 else
2008 rcu_assign_pointer(tr->filtered_no_pids, pid_list);
2009
2010 list_for_each_entry(file, &tr->events, list) {
2011 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
2012 }
2013
2014 if (filtered_pids) {
2015 tracepoint_synchronize_unregister();
2016 trace_pid_list_free(filtered_pids);
2017 } else if (pid_list && !other_pids) {
2018 register_pid_events(tr);
2019 }
2020
2021 /*
2022 * Ignoring of pids is done at task switch. But we have to
2023 * check for those tasks that are currently running.
2024 * Always do this in case a pid was appended or removed.
2025 */
2026 on_each_cpu(ignore_task_cpu, tr, 1);
2027
2028 out:
2029 mutex_unlock(&event_mutex);
2030
2031 if (ret > 0)
2032 *ppos += ret;
2033
2034 return ret;
2035 }
2036
2037 static ssize_t
ftrace_event_pid_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)2038 ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
2039 size_t cnt, loff_t *ppos)
2040 {
2041 return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
2042 }
2043
2044 static ssize_t
ftrace_event_npid_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)2045 ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
2046 size_t cnt, loff_t *ppos)
2047 {
2048 return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
2049 }
2050
2051 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
2052 static int ftrace_event_set_open(struct inode *inode, struct file *file);
2053 static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
2054 static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
2055 static int ftrace_event_release(struct inode *inode, struct file *file);
2056
2057 static const struct seq_operations show_event_seq_ops = {
2058 .start = t_start,
2059 .next = t_next,
2060 .show = t_show,
2061 .stop = t_stop,
2062 };
2063
2064 static const struct seq_operations show_set_event_seq_ops = {
2065 .start = s_start,
2066 .next = s_next,
2067 .show = t_show,
2068 .stop = t_stop,
2069 };
2070
2071 static const struct seq_operations show_set_pid_seq_ops = {
2072 .start = p_start,
2073 .next = p_next,
2074 .show = trace_pid_show,
2075 .stop = p_stop,
2076 };
2077
2078 static const struct seq_operations show_set_no_pid_seq_ops = {
2079 .start = np_start,
2080 .next = np_next,
2081 .show = trace_pid_show,
2082 .stop = p_stop,
2083 };
2084
2085 static const struct file_operations ftrace_avail_fops = {
2086 .open = ftrace_event_avail_open,
2087 .read = seq_read,
2088 .llseek = seq_lseek,
2089 .release = seq_release,
2090 };
2091
2092 static const struct file_operations ftrace_set_event_fops = {
2093 .open = ftrace_event_set_open,
2094 .read = seq_read,
2095 .write = ftrace_event_write,
2096 .llseek = seq_lseek,
2097 .release = ftrace_event_release,
2098 };
2099
2100 static const struct file_operations ftrace_set_event_pid_fops = {
2101 .open = ftrace_event_set_pid_open,
2102 .read = seq_read,
2103 .write = ftrace_event_pid_write,
2104 .llseek = seq_lseek,
2105 .release = ftrace_event_release,
2106 };
2107
2108 static const struct file_operations ftrace_set_event_notrace_pid_fops = {
2109 .open = ftrace_event_set_npid_open,
2110 .read = seq_read,
2111 .write = ftrace_event_npid_write,
2112 .llseek = seq_lseek,
2113 .release = ftrace_event_release,
2114 };
2115
2116 static const struct file_operations ftrace_enable_fops = {
2117 .open = tracing_open_file_tr,
2118 .read = event_enable_read,
2119 .write = event_enable_write,
2120 .release = tracing_release_file_tr,
2121 .llseek = default_llseek,
2122 };
2123
2124 static const struct file_operations ftrace_event_format_fops = {
2125 .open = trace_format_open,
2126 .read = seq_read,
2127 .llseek = seq_lseek,
2128 .release = seq_release,
2129 };
2130
2131 #ifdef CONFIG_PERF_EVENTS
2132 static const struct file_operations ftrace_event_id_fops = {
2133 .read = event_id_read,
2134 .llseek = default_llseek,
2135 };
2136 #endif
2137
2138 static const struct file_operations ftrace_event_filter_fops = {
2139 .open = tracing_open_file_tr,
2140 .read = event_filter_read,
2141 .write = event_filter_write,
2142 .release = tracing_release_file_tr,
2143 .llseek = default_llseek,
2144 };
2145
2146 static const struct file_operations ftrace_subsystem_filter_fops = {
2147 .open = subsystem_open,
2148 .read = subsystem_filter_read,
2149 .write = subsystem_filter_write,
2150 .llseek = default_llseek,
2151 .release = subsystem_release,
2152 };
2153
2154 static const struct file_operations ftrace_system_enable_fops = {
2155 .open = subsystem_open,
2156 .read = system_enable_read,
2157 .write = system_enable_write,
2158 .llseek = default_llseek,
2159 .release = subsystem_release,
2160 };
2161
2162 static const struct file_operations ftrace_tr_enable_fops = {
2163 .open = system_tr_open,
2164 .read = system_enable_read,
2165 .write = system_enable_write,
2166 .llseek = default_llseek,
2167 .release = subsystem_release,
2168 };
2169
2170 static const struct file_operations ftrace_show_header_fops = {
2171 .open = tracing_open_generic,
2172 .read = show_header,
2173 .llseek = default_llseek,
2174 };
2175
2176 static int
ftrace_event_open(struct inode * inode,struct file * file,const struct seq_operations * seq_ops)2177 ftrace_event_open(struct inode *inode, struct file *file,
2178 const struct seq_operations *seq_ops)
2179 {
2180 struct seq_file *m;
2181 int ret;
2182
2183 ret = security_locked_down(LOCKDOWN_TRACEFS);
2184 if (ret)
2185 return ret;
2186
2187 ret = seq_open(file, seq_ops);
2188 if (ret < 0)
2189 return ret;
2190 m = file->private_data;
2191 /* copy tr over to seq ops */
2192 m->private = inode->i_private;
2193
2194 return ret;
2195 }
2196
ftrace_event_release(struct inode * inode,struct file * file)2197 static int ftrace_event_release(struct inode *inode, struct file *file)
2198 {
2199 struct trace_array *tr = inode->i_private;
2200
2201 trace_array_put(tr);
2202
2203 return seq_release(inode, file);
2204 }
2205
2206 static int
ftrace_event_avail_open(struct inode * inode,struct file * file)2207 ftrace_event_avail_open(struct inode *inode, struct file *file)
2208 {
2209 const struct seq_operations *seq_ops = &show_event_seq_ops;
2210
2211 /* Checks for tracefs lockdown */
2212 return ftrace_event_open(inode, file, seq_ops);
2213 }
2214
2215 static int
ftrace_event_set_open(struct inode * inode,struct file * file)2216 ftrace_event_set_open(struct inode *inode, struct file *file)
2217 {
2218 const struct seq_operations *seq_ops = &show_set_event_seq_ops;
2219 struct trace_array *tr = inode->i_private;
2220 int ret;
2221
2222 ret = tracing_check_open_get_tr(tr);
2223 if (ret)
2224 return ret;
2225
2226 if ((file->f_mode & FMODE_WRITE) &&
2227 (file->f_flags & O_TRUNC))
2228 ftrace_clear_events(tr);
2229
2230 ret = ftrace_event_open(inode, file, seq_ops);
2231 if (ret < 0)
2232 trace_array_put(tr);
2233 return ret;
2234 }
2235
2236 static int
ftrace_event_set_pid_open(struct inode * inode,struct file * file)2237 ftrace_event_set_pid_open(struct inode *inode, struct file *file)
2238 {
2239 const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
2240 struct trace_array *tr = inode->i_private;
2241 int ret;
2242
2243 ret = tracing_check_open_get_tr(tr);
2244 if (ret)
2245 return ret;
2246
2247 if ((file->f_mode & FMODE_WRITE) &&
2248 (file->f_flags & O_TRUNC))
2249 ftrace_clear_event_pids(tr, TRACE_PIDS);
2250
2251 ret = ftrace_event_open(inode, file, seq_ops);
2252 if (ret < 0)
2253 trace_array_put(tr);
2254 return ret;
2255 }
2256
2257 static int
ftrace_event_set_npid_open(struct inode * inode,struct file * file)2258 ftrace_event_set_npid_open(struct inode *inode, struct file *file)
2259 {
2260 const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops;
2261 struct trace_array *tr = inode->i_private;
2262 int ret;
2263
2264 ret = tracing_check_open_get_tr(tr);
2265 if (ret)
2266 return ret;
2267
2268 if ((file->f_mode & FMODE_WRITE) &&
2269 (file->f_flags & O_TRUNC))
2270 ftrace_clear_event_pids(tr, TRACE_NO_PIDS);
2271
2272 ret = ftrace_event_open(inode, file, seq_ops);
2273 if (ret < 0)
2274 trace_array_put(tr);
2275 return ret;
2276 }
2277
2278 static struct event_subsystem *
create_new_subsystem(const char * name)2279 create_new_subsystem(const char *name)
2280 {
2281 struct event_subsystem *system;
2282
2283 /* need to create new entry */
2284 system = kmalloc(sizeof(*system), GFP_KERNEL);
2285 if (!system)
2286 return NULL;
2287
2288 system->ref_count = 1;
2289
2290 /* Only allocate if dynamic (kprobes and modules) */
2291 system->name = kstrdup_const(name, GFP_KERNEL);
2292 if (!system->name)
2293 goto out_free;
2294
2295 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
2296 if (!system->filter)
2297 goto out_free;
2298
2299 list_add(&system->list, &event_subsystems);
2300
2301 return system;
2302
2303 out_free:
2304 kfree_const(system->name);
2305 kfree(system);
2306 return NULL;
2307 }
2308
system_callback(const char * name,umode_t * mode,void ** data,const struct file_operations ** fops)2309 static int system_callback(const char *name, umode_t *mode, void **data,
2310 const struct file_operations **fops)
2311 {
2312 if (strcmp(name, "filter") == 0)
2313 *fops = &ftrace_subsystem_filter_fops;
2314
2315 else if (strcmp(name, "enable") == 0)
2316 *fops = &ftrace_system_enable_fops;
2317
2318 else
2319 return 0;
2320
2321 *mode = TRACE_MODE_WRITE;
2322 return 1;
2323 }
2324
2325 static struct eventfs_inode *
event_subsystem_dir(struct trace_array * tr,const char * name,struct trace_event_file * file,struct eventfs_inode * parent)2326 event_subsystem_dir(struct trace_array *tr, const char *name,
2327 struct trace_event_file *file, struct eventfs_inode *parent)
2328 {
2329 struct event_subsystem *system, *iter;
2330 struct trace_subsystem_dir *dir;
2331 struct eventfs_inode *ei;
2332 int nr_entries;
2333 static struct eventfs_entry system_entries[] = {
2334 {
2335 .name = "filter",
2336 .callback = system_callback,
2337 },
2338 {
2339 .name = "enable",
2340 .callback = system_callback,
2341 }
2342 };
2343
2344 /* First see if we did not already create this dir */
2345 list_for_each_entry(dir, &tr->systems, list) {
2346 system = dir->subsystem;
2347 if (strcmp(system->name, name) == 0) {
2348 dir->nr_events++;
2349 file->system = dir;
2350 return dir->ei;
2351 }
2352 }
2353
2354 /* Now see if the system itself exists. */
2355 system = NULL;
2356 list_for_each_entry(iter, &event_subsystems, list) {
2357 if (strcmp(iter->name, name) == 0) {
2358 system = iter;
2359 break;
2360 }
2361 }
2362
2363 dir = kmalloc(sizeof(*dir), GFP_KERNEL);
2364 if (!dir)
2365 goto out_fail;
2366
2367 if (!system) {
2368 system = create_new_subsystem(name);
2369 if (!system)
2370 goto out_free;
2371 } else
2372 __get_system(system);
2373
2374 /* ftrace only has directories no files */
2375 if (strcmp(name, "ftrace") == 0)
2376 nr_entries = 0;
2377 else
2378 nr_entries = ARRAY_SIZE(system_entries);
2379
2380 ei = eventfs_create_dir(name, parent, system_entries, nr_entries, dir);
2381 if (IS_ERR(ei)) {
2382 pr_warn("Failed to create system directory %s\n", name);
2383 __put_system(system);
2384 goto out_free;
2385 }
2386
2387 dir->ei = ei;
2388 dir->tr = tr;
2389 dir->ref_count = 1;
2390 dir->nr_events = 1;
2391 dir->subsystem = system;
2392 file->system = dir;
2393
2394 list_add(&dir->list, &tr->systems);
2395
2396 return dir->ei;
2397
2398 out_free:
2399 kfree(dir);
2400 out_fail:
2401 /* Only print this message if failed on memory allocation */
2402 if (!dir || !system)
2403 pr_warn("No memory to create event subsystem %s\n", name);
2404 return NULL;
2405 }
2406
2407 static int
event_define_fields(struct trace_event_call * call)2408 event_define_fields(struct trace_event_call *call)
2409 {
2410 struct list_head *head;
2411 int ret = 0;
2412
2413 /*
2414 * Other events may have the same class. Only update
2415 * the fields if they are not already defined.
2416 */
2417 head = trace_get_fields(call);
2418 if (list_empty(head)) {
2419 struct trace_event_fields *field = call->class->fields_array;
2420 unsigned int offset = sizeof(struct trace_entry);
2421
2422 for (; field->type; field++) {
2423 if (field->type == TRACE_FUNCTION_TYPE) {
2424 field->define_fields(call);
2425 break;
2426 }
2427
2428 offset = ALIGN(offset, field->align);
2429 ret = trace_define_field_ext(call, field->type, field->name,
2430 offset, field->size,
2431 field->is_signed, field->filter_type,
2432 field->len);
2433 if (WARN_ON_ONCE(ret)) {
2434 pr_err("error code is %d\n", ret);
2435 break;
2436 }
2437
2438 offset += field->size;
2439 }
2440 }
2441
2442 return ret;
2443 }
2444
event_callback(const char * name,umode_t * mode,void ** data,const struct file_operations ** fops)2445 static int event_callback(const char *name, umode_t *mode, void **data,
2446 const struct file_operations **fops)
2447 {
2448 struct trace_event_file *file = *data;
2449 struct trace_event_call *call = file->event_call;
2450
2451 if (strcmp(name, "format") == 0) {
2452 *mode = TRACE_MODE_READ;
2453 *fops = &ftrace_event_format_fops;
2454 *data = call;
2455 return 1;
2456 }
2457
2458 /*
2459 * Only event directories that can be enabled should have
2460 * triggers or filters, with the exception of the "print"
2461 * event that can have a "trigger" file.
2462 */
2463 if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
2464 if (call->class->reg && strcmp(name, "enable") == 0) {
2465 *mode = TRACE_MODE_WRITE;
2466 *fops = &ftrace_enable_fops;
2467 return 1;
2468 }
2469
2470 if (strcmp(name, "filter") == 0) {
2471 *mode = TRACE_MODE_WRITE;
2472 *fops = &ftrace_event_filter_fops;
2473 return 1;
2474 }
2475 }
2476
2477 if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
2478 strcmp(trace_event_name(call), "print") == 0) {
2479 if (strcmp(name, "trigger") == 0) {
2480 *mode = TRACE_MODE_WRITE;
2481 *fops = &event_trigger_fops;
2482 return 1;
2483 }
2484 }
2485
2486 #ifdef CONFIG_PERF_EVENTS
2487 if (call->event.type && call->class->reg &&
2488 strcmp(name, "id") == 0) {
2489 *mode = TRACE_MODE_READ;
2490 *data = (void *)(long)call->event.type;
2491 *fops = &ftrace_event_id_fops;
2492 return 1;
2493 }
2494 #endif
2495
2496 #ifdef CONFIG_HIST_TRIGGERS
2497 if (strcmp(name, "hist") == 0) {
2498 *mode = TRACE_MODE_READ;
2499 *fops = &event_hist_fops;
2500 return 1;
2501 }
2502 #endif
2503 #ifdef CONFIG_HIST_TRIGGERS_DEBUG
2504 if (strcmp(name, "hist_debug") == 0) {
2505 *mode = TRACE_MODE_READ;
2506 *fops = &event_hist_debug_fops;
2507 return 1;
2508 }
2509 #endif
2510 #ifdef CONFIG_TRACE_EVENT_INJECT
2511 if (call->event.type && call->class->reg &&
2512 strcmp(name, "inject") == 0) {
2513 *mode = 0200;
2514 *fops = &event_inject_fops;
2515 return 1;
2516 }
2517 #endif
2518 return 0;
2519 }
2520
2521 /* The file is incremented on creation and freeing the enable file decrements it */
event_release(const char * name,void * data)2522 static void event_release(const char *name, void *data)
2523 {
2524 struct trace_event_file *file = data;
2525
2526 event_file_put(file);
2527 }
2528
2529 static int
event_create_dir(struct eventfs_inode * parent,struct trace_event_file * file)2530 event_create_dir(struct eventfs_inode *parent, struct trace_event_file *file)
2531 {
2532 struct trace_event_call *call = file->event_call;
2533 struct trace_array *tr = file->tr;
2534 struct eventfs_inode *e_events;
2535 struct eventfs_inode *ei;
2536 const char *name;
2537 int nr_entries;
2538 int ret;
2539 static struct eventfs_entry event_entries[] = {
2540 {
2541 .name = "enable",
2542 .callback = event_callback,
2543 .release = event_release,
2544 },
2545 {
2546 .name = "filter",
2547 .callback = event_callback,
2548 },
2549 {
2550 .name = "trigger",
2551 .callback = event_callback,
2552 },
2553 {
2554 .name = "format",
2555 .callback = event_callback,
2556 },
2557 #ifdef CONFIG_PERF_EVENTS
2558 {
2559 .name = "id",
2560 .callback = event_callback,
2561 },
2562 #endif
2563 #ifdef CONFIG_HIST_TRIGGERS
2564 {
2565 .name = "hist",
2566 .callback = event_callback,
2567 },
2568 #endif
2569 #ifdef CONFIG_HIST_TRIGGERS_DEBUG
2570 {
2571 .name = "hist_debug",
2572 .callback = event_callback,
2573 },
2574 #endif
2575 #ifdef CONFIG_TRACE_EVENT_INJECT
2576 {
2577 .name = "inject",
2578 .callback = event_callback,
2579 },
2580 #endif
2581 };
2582
2583 /*
2584 * If the trace point header did not define TRACE_SYSTEM
2585 * then the system would be called "TRACE_SYSTEM". This should
2586 * never happen.
2587 */
2588 if (WARN_ON_ONCE(strcmp(call->class->system, TRACE_SYSTEM) == 0))
2589 return -ENODEV;
2590
2591 e_events = event_subsystem_dir(tr, call->class->system, file, parent);
2592 if (!e_events)
2593 return -ENOMEM;
2594
2595 nr_entries = ARRAY_SIZE(event_entries);
2596
2597 name = trace_event_name(call);
2598 ei = eventfs_create_dir(name, e_events, event_entries, nr_entries, file);
2599 if (IS_ERR(ei)) {
2600 pr_warn("Could not create tracefs '%s' directory\n", name);
2601 return -1;
2602 }
2603
2604 file->ei = ei;
2605
2606 ret = event_define_fields(call);
2607 if (ret < 0) {
2608 pr_warn("Could not initialize trace point events/%s\n", name);
2609 return ret;
2610 }
2611
2612 /* Gets decremented on freeing of the "enable" file */
2613 event_file_get(file);
2614
2615 return 0;
2616 }
2617
remove_event_from_tracers(struct trace_event_call * call)2618 static void remove_event_from_tracers(struct trace_event_call *call)
2619 {
2620 struct trace_event_file *file;
2621 struct trace_array *tr;
2622
2623 do_for_each_event_file_safe(tr, file) {
2624 if (file->event_call != call)
2625 continue;
2626
2627 remove_event_file_dir(file);
2628 /*
2629 * The do_for_each_event_file_safe() is
2630 * a double loop. After finding the call for this
2631 * trace_array, we use break to jump to the next
2632 * trace_array.
2633 */
2634 break;
2635 } while_for_each_event_file();
2636 }
2637
event_remove(struct trace_event_call * call)2638 static void event_remove(struct trace_event_call *call)
2639 {
2640 struct trace_array *tr;
2641 struct trace_event_file *file;
2642
2643 do_for_each_event_file(tr, file) {
2644 if (file->event_call != call)
2645 continue;
2646
2647 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2648 tr->clear_trace = true;
2649
2650 ftrace_event_enable_disable(file, 0);
2651 /*
2652 * The do_for_each_event_file() is
2653 * a double loop. After finding the call for this
2654 * trace_array, we use break to jump to the next
2655 * trace_array.
2656 */
2657 break;
2658 } while_for_each_event_file();
2659
2660 if (call->event.funcs)
2661 __unregister_trace_event(&call->event);
2662 remove_event_from_tracers(call);
2663 list_del(&call->list);
2664 }
2665
event_init(struct trace_event_call * call)2666 static int event_init(struct trace_event_call *call)
2667 {
2668 int ret = 0;
2669 const char *name;
2670
2671 name = trace_event_name(call);
2672 if (WARN_ON(!name))
2673 return -EINVAL;
2674
2675 if (call->class->raw_init) {
2676 ret = call->class->raw_init(call);
2677 if (ret < 0 && ret != -ENOSYS)
2678 pr_warn("Could not initialize trace events/%s\n", name);
2679 }
2680
2681 return ret;
2682 }
2683
2684 static int
__register_event(struct trace_event_call * call,struct module * mod)2685 __register_event(struct trace_event_call *call, struct module *mod)
2686 {
2687 int ret;
2688
2689 ret = event_init(call);
2690 if (ret < 0)
2691 return ret;
2692
2693 list_add(&call->list, &ftrace_events);
2694 if (call->flags & TRACE_EVENT_FL_DYNAMIC)
2695 atomic_set(&call->refcnt, 0);
2696 else
2697 call->module = mod;
2698
2699 return 0;
2700 }
2701
eval_replace(char * ptr,struct trace_eval_map * map,int len)2702 static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2703 {
2704 int rlen;
2705 int elen;
2706
2707 /* Find the length of the eval value as a string */
2708 elen = snprintf(ptr, 0, "%ld", map->eval_value);
2709 /* Make sure there's enough room to replace the string with the value */
2710 if (len < elen)
2711 return NULL;
2712
2713 snprintf(ptr, elen + 1, "%ld", map->eval_value);
2714
2715 /* Get the rest of the string of ptr */
2716 rlen = strlen(ptr + len);
2717 memmove(ptr + elen, ptr + len, rlen);
2718 /* Make sure we end the new string */
2719 ptr[elen + rlen] = 0;
2720
2721 return ptr + elen;
2722 }
2723
update_event_printk(struct trace_event_call * call,struct trace_eval_map * map)2724 static void update_event_printk(struct trace_event_call *call,
2725 struct trace_eval_map *map)
2726 {
2727 char *ptr;
2728 int quote = 0;
2729 int len = strlen(map->eval_string);
2730
2731 for (ptr = call->print_fmt; *ptr; ptr++) {
2732 if (*ptr == '\\') {
2733 ptr++;
2734 /* paranoid */
2735 if (!*ptr)
2736 break;
2737 continue;
2738 }
2739 if (*ptr == '"') {
2740 quote ^= 1;
2741 continue;
2742 }
2743 if (quote)
2744 continue;
2745 if (isdigit(*ptr)) {
2746 /* skip numbers */
2747 do {
2748 ptr++;
2749 /* Check for alpha chars like ULL */
2750 } while (isalnum(*ptr));
2751 if (!*ptr)
2752 break;
2753 /*
2754 * A number must have some kind of delimiter after
2755 * it, and we can ignore that too.
2756 */
2757 continue;
2758 }
2759 if (isalpha(*ptr) || *ptr == '_') {
2760 if (strncmp(map->eval_string, ptr, len) == 0 &&
2761 !isalnum(ptr[len]) && ptr[len] != '_') {
2762 ptr = eval_replace(ptr, map, len);
2763 /* enum/sizeof string smaller than value */
2764 if (WARN_ON_ONCE(!ptr))
2765 return;
2766 /*
2767 * No need to decrement here, as eval_replace()
2768 * returns the pointer to the character passed
2769 * the eval, and two evals can not be placed
2770 * back to back without something in between.
2771 * We can skip that something in between.
2772 */
2773 continue;
2774 }
2775 skip_more:
2776 do {
2777 ptr++;
2778 } while (isalnum(*ptr) || *ptr == '_');
2779 if (!*ptr)
2780 break;
2781 /*
2782 * If what comes after this variable is a '.' or
2783 * '->' then we can continue to ignore that string.
2784 */
2785 if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2786 ptr += *ptr == '.' ? 1 : 2;
2787 if (!*ptr)
2788 break;
2789 goto skip_more;
2790 }
2791 /*
2792 * Once again, we can skip the delimiter that came
2793 * after the string.
2794 */
2795 continue;
2796 }
2797 }
2798 }
2799
add_str_to_module(struct module * module,char * str)2800 static void add_str_to_module(struct module *module, char *str)
2801 {
2802 struct module_string *modstr;
2803
2804 modstr = kmalloc(sizeof(*modstr), GFP_KERNEL);
2805
2806 /*
2807 * If we failed to allocate memory here, then we'll just
2808 * let the str memory leak when the module is removed.
2809 * If this fails to allocate, there's worse problems than
2810 * a leaked string on module removal.
2811 */
2812 if (WARN_ON_ONCE(!modstr))
2813 return;
2814
2815 modstr->module = module;
2816 modstr->str = str;
2817
2818 list_add(&modstr->next, &module_strings);
2819 }
2820
update_event_fields(struct trace_event_call * call,struct trace_eval_map * map)2821 static void update_event_fields(struct trace_event_call *call,
2822 struct trace_eval_map *map)
2823 {
2824 struct ftrace_event_field *field;
2825 struct list_head *head;
2826 char *ptr;
2827 char *str;
2828 int len = strlen(map->eval_string);
2829
2830 /* Dynamic events should never have field maps */
2831 if (WARN_ON_ONCE(call->flags & TRACE_EVENT_FL_DYNAMIC))
2832 return;
2833
2834 head = trace_get_fields(call);
2835 list_for_each_entry(field, head, link) {
2836 ptr = strchr(field->type, '[');
2837 if (!ptr)
2838 continue;
2839 ptr++;
2840
2841 if (!isalpha(*ptr) && *ptr != '_')
2842 continue;
2843
2844 if (strncmp(map->eval_string, ptr, len) != 0)
2845 continue;
2846
2847 str = kstrdup(field->type, GFP_KERNEL);
2848 if (WARN_ON_ONCE(!str))
2849 return;
2850 ptr = str + (ptr - field->type);
2851 ptr = eval_replace(ptr, map, len);
2852 /* enum/sizeof string smaller than value */
2853 if (WARN_ON_ONCE(!ptr)) {
2854 kfree(str);
2855 continue;
2856 }
2857
2858 /*
2859 * If the event is part of a module, then we need to free the string
2860 * when the module is removed. Otherwise, it will stay allocated
2861 * until a reboot.
2862 */
2863 if (call->module)
2864 add_str_to_module(call->module, str);
2865
2866 field->type = str;
2867 }
2868 }
2869
trace_event_eval_update(struct trace_eval_map ** map,int len)2870 void trace_event_eval_update(struct trace_eval_map **map, int len)
2871 {
2872 struct trace_event_call *call, *p;
2873 const char *last_system = NULL;
2874 bool first = false;
2875 int last_i;
2876 int i;
2877
2878 down_write(&trace_event_sem);
2879 list_for_each_entry_safe(call, p, &ftrace_events, list) {
2880 /* events are usually grouped together with systems */
2881 if (!last_system || call->class->system != last_system) {
2882 first = true;
2883 last_i = 0;
2884 last_system = call->class->system;
2885 }
2886
2887 /*
2888 * Since calls are grouped by systems, the likelihood that the
2889 * next call in the iteration belongs to the same system as the
2890 * previous call is high. As an optimization, we skip searching
2891 * for a map[] that matches the call's system if the last call
2892 * was from the same system. That's what last_i is for. If the
2893 * call has the same system as the previous call, then last_i
2894 * will be the index of the first map[] that has a matching
2895 * system.
2896 */
2897 for (i = last_i; i < len; i++) {
2898 if (call->class->system == map[i]->system) {
2899 /* Save the first system if need be */
2900 if (first) {
2901 last_i = i;
2902 first = false;
2903 }
2904 update_event_printk(call, map[i]);
2905 update_event_fields(call, map[i]);
2906 }
2907 }
2908 cond_resched();
2909 }
2910 up_write(&trace_event_sem);
2911 }
2912
2913 static struct trace_event_file *
trace_create_new_event(struct trace_event_call * call,struct trace_array * tr)2914 trace_create_new_event(struct trace_event_call *call,
2915 struct trace_array *tr)
2916 {
2917 struct trace_pid_list *no_pid_list;
2918 struct trace_pid_list *pid_list;
2919 struct trace_event_file *file;
2920 unsigned int first;
2921
2922 file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2923 if (!file)
2924 return NULL;
2925
2926 pid_list = rcu_dereference_protected(tr->filtered_pids,
2927 lockdep_is_held(&event_mutex));
2928 no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
2929 lockdep_is_held(&event_mutex));
2930
2931 if (!trace_pid_list_first(pid_list, &first) ||
2932 !trace_pid_list_first(no_pid_list, &first))
2933 file->flags |= EVENT_FILE_FL_PID_FILTER;
2934
2935 file->event_call = call;
2936 file->tr = tr;
2937 atomic_set(&file->sm_ref, 0);
2938 atomic_set(&file->tm_ref, 0);
2939 INIT_LIST_HEAD(&file->triggers);
2940 list_add(&file->list, &tr->events);
2941 event_file_get(file);
2942
2943 return file;
2944 }
2945
2946 #define MAX_BOOT_TRIGGERS 32
2947
2948 static struct boot_triggers {
2949 const char *event;
2950 char *trigger;
2951 } bootup_triggers[MAX_BOOT_TRIGGERS];
2952
2953 static char bootup_trigger_buf[COMMAND_LINE_SIZE];
2954 static int nr_boot_triggers;
2955
setup_trace_triggers(char * str)2956 static __init int setup_trace_triggers(char *str)
2957 {
2958 char *trigger;
2959 char *buf;
2960 int i;
2961
2962 strscpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE);
2963 ring_buffer_expanded = true;
2964 disable_tracing_selftest("running event triggers");
2965
2966 buf = bootup_trigger_buf;
2967 for (i = 0; i < MAX_BOOT_TRIGGERS; i++) {
2968 trigger = strsep(&buf, ",");
2969 if (!trigger)
2970 break;
2971 bootup_triggers[i].event = strsep(&trigger, ".");
2972 bootup_triggers[i].trigger = trigger;
2973 if (!bootup_triggers[i].trigger)
2974 break;
2975 }
2976
2977 nr_boot_triggers = i;
2978 return 1;
2979 }
2980 __setup("trace_trigger=", setup_trace_triggers);
2981
2982 /* Add an event to a trace directory */
2983 static int
__trace_add_new_event(struct trace_event_call * call,struct trace_array * tr)2984 __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2985 {
2986 struct trace_event_file *file;
2987
2988 file = trace_create_new_event(call, tr);
2989 if (!file)
2990 return -ENOMEM;
2991
2992 if (eventdir_initialized)
2993 return event_create_dir(tr->event_dir, file);
2994 else
2995 return event_define_fields(call);
2996 }
2997
trace_early_triggers(struct trace_event_file * file,const char * name)2998 static void trace_early_triggers(struct trace_event_file *file, const char *name)
2999 {
3000 int ret;
3001 int i;
3002
3003 for (i = 0; i < nr_boot_triggers; i++) {
3004 if (strcmp(name, bootup_triggers[i].event))
3005 continue;
3006 mutex_lock(&event_mutex);
3007 ret = trigger_process_regex(file, bootup_triggers[i].trigger);
3008 mutex_unlock(&event_mutex);
3009 if (ret)
3010 pr_err("Failed to register trigger '%s' on event %s\n",
3011 bootup_triggers[i].trigger,
3012 bootup_triggers[i].event);
3013 }
3014 }
3015
3016 /*
3017 * Just create a descriptor for early init. A descriptor is required
3018 * for enabling events at boot. We want to enable events before
3019 * the filesystem is initialized.
3020 */
3021 static int
__trace_early_add_new_event(struct trace_event_call * call,struct trace_array * tr)3022 __trace_early_add_new_event(struct trace_event_call *call,
3023 struct trace_array *tr)
3024 {
3025 struct trace_event_file *file;
3026 int ret;
3027
3028 file = trace_create_new_event(call, tr);
3029 if (!file)
3030 return -ENOMEM;
3031
3032 ret = event_define_fields(call);
3033 if (ret)
3034 return ret;
3035
3036 trace_early_triggers(file, trace_event_name(call));
3037
3038 return 0;
3039 }
3040
3041 struct ftrace_module_file_ops;
3042 static void __add_event_to_tracers(struct trace_event_call *call);
3043
3044 /* Add an additional event_call dynamically */
trace_add_event_call(struct trace_event_call * call)3045 int trace_add_event_call(struct trace_event_call *call)
3046 {
3047 int ret;
3048 lockdep_assert_held(&event_mutex);
3049
3050 mutex_lock(&trace_types_lock);
3051
3052 ret = __register_event(call, NULL);
3053 if (ret >= 0)
3054 __add_event_to_tracers(call);
3055
3056 mutex_unlock(&trace_types_lock);
3057 return ret;
3058 }
3059 EXPORT_SYMBOL_GPL(trace_add_event_call);
3060
3061 /*
3062 * Must be called under locking of trace_types_lock, event_mutex and
3063 * trace_event_sem.
3064 */
__trace_remove_event_call(struct trace_event_call * call)3065 static void __trace_remove_event_call(struct trace_event_call *call)
3066 {
3067 event_remove(call);
3068 trace_destroy_fields(call);
3069 free_event_filter(call->filter);
3070 call->filter = NULL;
3071 }
3072
probe_remove_event_call(struct trace_event_call * call)3073 static int probe_remove_event_call(struct trace_event_call *call)
3074 {
3075 struct trace_array *tr;
3076 struct trace_event_file *file;
3077
3078 #ifdef CONFIG_PERF_EVENTS
3079 if (call->perf_refcount)
3080 return -EBUSY;
3081 #endif
3082 do_for_each_event_file(tr, file) {
3083 if (file->event_call != call)
3084 continue;
3085 /*
3086 * We can't rely on ftrace_event_enable_disable(enable => 0)
3087 * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
3088 * TRACE_REG_UNREGISTER.
3089 */
3090 if (file->flags & EVENT_FILE_FL_ENABLED)
3091 goto busy;
3092
3093 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
3094 tr->clear_trace = true;
3095 /*
3096 * The do_for_each_event_file_safe() is
3097 * a double loop. After finding the call for this
3098 * trace_array, we use break to jump to the next
3099 * trace_array.
3100 */
3101 break;
3102 } while_for_each_event_file();
3103
3104 __trace_remove_event_call(call);
3105
3106 return 0;
3107 busy:
3108 /* No need to clear the trace now */
3109 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
3110 tr->clear_trace = false;
3111 }
3112 return -EBUSY;
3113 }
3114
3115 /* Remove an event_call */
trace_remove_event_call(struct trace_event_call * call)3116 int trace_remove_event_call(struct trace_event_call *call)
3117 {
3118 int ret;
3119
3120 lockdep_assert_held(&event_mutex);
3121
3122 mutex_lock(&trace_types_lock);
3123 down_write(&trace_event_sem);
3124 ret = probe_remove_event_call(call);
3125 up_write(&trace_event_sem);
3126 mutex_unlock(&trace_types_lock);
3127
3128 return ret;
3129 }
3130 EXPORT_SYMBOL_GPL(trace_remove_event_call);
3131
3132 #define for_each_event(event, start, end) \
3133 for (event = start; \
3134 (unsigned long)event < (unsigned long)end; \
3135 event++)
3136
3137 #ifdef CONFIG_MODULES
3138
trace_module_add_events(struct module * mod)3139 static void trace_module_add_events(struct module *mod)
3140 {
3141 struct trace_event_call **call, **start, **end;
3142
3143 if (!mod->num_trace_events)
3144 return;
3145
3146 /* Don't add infrastructure for mods without tracepoints */
3147 if (trace_module_has_bad_taint(mod)) {
3148 pr_err("%s: module has bad taint, not creating trace events\n",
3149 mod->name);
3150 return;
3151 }
3152
3153 start = mod->trace_events;
3154 end = mod->trace_events + mod->num_trace_events;
3155
3156 for_each_event(call, start, end) {
3157 __register_event(*call, mod);
3158 __add_event_to_tracers(*call);
3159 }
3160 }
3161
trace_module_remove_events(struct module * mod)3162 static void trace_module_remove_events(struct module *mod)
3163 {
3164 struct trace_event_call *call, *p;
3165 struct module_string *modstr, *m;
3166
3167 down_write(&trace_event_sem);
3168 list_for_each_entry_safe(call, p, &ftrace_events, list) {
3169 if ((call->flags & TRACE_EVENT_FL_DYNAMIC) || !call->module)
3170 continue;
3171 if (call->module == mod)
3172 __trace_remove_event_call(call);
3173 }
3174 /* Check for any strings allocade for this module */
3175 list_for_each_entry_safe(modstr, m, &module_strings, next) {
3176 if (modstr->module != mod)
3177 continue;
3178 list_del(&modstr->next);
3179 kfree(modstr->str);
3180 kfree(modstr);
3181 }
3182 up_write(&trace_event_sem);
3183
3184 /*
3185 * It is safest to reset the ring buffer if the module being unloaded
3186 * registered any events that were used. The only worry is if
3187 * a new module gets loaded, and takes on the same id as the events
3188 * of this module. When printing out the buffer, traced events left
3189 * over from this module may be passed to the new module events and
3190 * unexpected results may occur.
3191 */
3192 tracing_reset_all_online_cpus_unlocked();
3193 }
3194
trace_module_notify(struct notifier_block * self,unsigned long val,void * data)3195 static int trace_module_notify(struct notifier_block *self,
3196 unsigned long val, void *data)
3197 {
3198 struct module *mod = data;
3199
3200 mutex_lock(&event_mutex);
3201 mutex_lock(&trace_types_lock);
3202 switch (val) {
3203 case MODULE_STATE_COMING:
3204 trace_module_add_events(mod);
3205 break;
3206 case MODULE_STATE_GOING:
3207 trace_module_remove_events(mod);
3208 break;
3209 }
3210 mutex_unlock(&trace_types_lock);
3211 mutex_unlock(&event_mutex);
3212
3213 return NOTIFY_OK;
3214 }
3215
3216 static struct notifier_block trace_module_nb = {
3217 .notifier_call = trace_module_notify,
3218 .priority = 1, /* higher than trace.c module notify */
3219 };
3220 #endif /* CONFIG_MODULES */
3221
3222 /* Create a new event directory structure for a trace directory. */
3223 static void
__trace_add_event_dirs(struct trace_array * tr)3224 __trace_add_event_dirs(struct trace_array *tr)
3225 {
3226 struct trace_event_call *call;
3227 int ret;
3228
3229 list_for_each_entry(call, &ftrace_events, list) {
3230 ret = __trace_add_new_event(call, tr);
3231 if (ret < 0)
3232 pr_warn("Could not create directory for event %s\n",
3233 trace_event_name(call));
3234 }
3235 }
3236
3237 /* Returns any file that matches the system and event */
3238 struct trace_event_file *
__find_event_file(struct trace_array * tr,const char * system,const char * event)3239 __find_event_file(struct trace_array *tr, const char *system, const char *event)
3240 {
3241 struct trace_event_file *file;
3242 struct trace_event_call *call;
3243 const char *name;
3244
3245 list_for_each_entry(file, &tr->events, list) {
3246
3247 call = file->event_call;
3248 name = trace_event_name(call);
3249
3250 if (!name || !call->class)
3251 continue;
3252
3253 if (strcmp(event, name) == 0 &&
3254 strcmp(system, call->class->system) == 0)
3255 return file;
3256 }
3257 return NULL;
3258 }
3259
3260 /* Returns valid trace event files that match system and event */
3261 struct trace_event_file *
find_event_file(struct trace_array * tr,const char * system,const char * event)3262 find_event_file(struct trace_array *tr, const char *system, const char *event)
3263 {
3264 struct trace_event_file *file;
3265
3266 file = __find_event_file(tr, system, event);
3267 if (!file || !file->event_call->class->reg ||
3268 file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
3269 return NULL;
3270
3271 return file;
3272 }
3273
3274 /**
3275 * trace_get_event_file - Find and return a trace event file
3276 * @instance: The name of the trace instance containing the event
3277 * @system: The name of the system containing the event
3278 * @event: The name of the event
3279 *
3280 * Return a trace event file given the trace instance name, trace
3281 * system, and trace event name. If the instance name is NULL, it
3282 * refers to the top-level trace array.
3283 *
3284 * This function will look it up and return it if found, after calling
3285 * trace_array_get() to prevent the instance from going away, and
3286 * increment the event's module refcount to prevent it from being
3287 * removed.
3288 *
3289 * To release the file, call trace_put_event_file(), which will call
3290 * trace_array_put() and decrement the event's module refcount.
3291 *
3292 * Return: The trace event on success, ERR_PTR otherwise.
3293 */
trace_get_event_file(const char * instance,const char * system,const char * event)3294 struct trace_event_file *trace_get_event_file(const char *instance,
3295 const char *system,
3296 const char *event)
3297 {
3298 struct trace_array *tr = top_trace_array();
3299 struct trace_event_file *file = NULL;
3300 int ret = -EINVAL;
3301
3302 if (instance) {
3303 tr = trace_array_find_get(instance);
3304 if (!tr)
3305 return ERR_PTR(-ENOENT);
3306 } else {
3307 ret = trace_array_get(tr);
3308 if (ret)
3309 return ERR_PTR(ret);
3310 }
3311
3312 mutex_lock(&event_mutex);
3313
3314 file = find_event_file(tr, system, event);
3315 if (!file) {
3316 trace_array_put(tr);
3317 ret = -EINVAL;
3318 goto out;
3319 }
3320
3321 /* Don't let event modules unload while in use */
3322 ret = trace_event_try_get_ref(file->event_call);
3323 if (!ret) {
3324 trace_array_put(tr);
3325 ret = -EBUSY;
3326 goto out;
3327 }
3328
3329 ret = 0;
3330 out:
3331 mutex_unlock(&event_mutex);
3332
3333 if (ret)
3334 file = ERR_PTR(ret);
3335
3336 return file;
3337 }
3338 EXPORT_SYMBOL_GPL(trace_get_event_file);
3339
3340 /**
3341 * trace_put_event_file - Release a file from trace_get_event_file()
3342 * @file: The trace event file
3343 *
3344 * If a file was retrieved using trace_get_event_file(), this should
3345 * be called when it's no longer needed. It will cancel the previous
3346 * trace_array_get() called by that function, and decrement the
3347 * event's module refcount.
3348 */
trace_put_event_file(struct trace_event_file * file)3349 void trace_put_event_file(struct trace_event_file *file)
3350 {
3351 mutex_lock(&event_mutex);
3352 trace_event_put_ref(file->event_call);
3353 mutex_unlock(&event_mutex);
3354
3355 trace_array_put(file->tr);
3356 }
3357 EXPORT_SYMBOL_GPL(trace_put_event_file);
3358
3359 #ifdef CONFIG_DYNAMIC_FTRACE
3360
3361 /* Avoid typos */
3362 #define ENABLE_EVENT_STR "enable_event"
3363 #define DISABLE_EVENT_STR "disable_event"
3364
3365 struct event_probe_data {
3366 struct trace_event_file *file;
3367 unsigned long count;
3368 int ref;
3369 bool enable;
3370 };
3371
update_event_probe(struct event_probe_data * data)3372 static void update_event_probe(struct event_probe_data *data)
3373 {
3374 if (data->enable)
3375 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3376 else
3377 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3378 }
3379
3380 static void
event_enable_probe(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)3381 event_enable_probe(unsigned long ip, unsigned long parent_ip,
3382 struct trace_array *tr, struct ftrace_probe_ops *ops,
3383 void *data)
3384 {
3385 struct ftrace_func_mapper *mapper = data;
3386 struct event_probe_data *edata;
3387 void **pdata;
3388
3389 pdata = ftrace_func_mapper_find_ip(mapper, ip);
3390 if (!pdata || !*pdata)
3391 return;
3392
3393 edata = *pdata;
3394 update_event_probe(edata);
3395 }
3396
3397 static void
event_enable_count_probe(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)3398 event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
3399 struct trace_array *tr, struct ftrace_probe_ops *ops,
3400 void *data)
3401 {
3402 struct ftrace_func_mapper *mapper = data;
3403 struct event_probe_data *edata;
3404 void **pdata;
3405
3406 pdata = ftrace_func_mapper_find_ip(mapper, ip);
3407 if (!pdata || !*pdata)
3408 return;
3409
3410 edata = *pdata;
3411
3412 if (!edata->count)
3413 return;
3414
3415 /* Skip if the event is in a state we want to switch to */
3416 if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
3417 return;
3418
3419 if (edata->count != -1)
3420 (edata->count)--;
3421
3422 update_event_probe(edata);
3423 }
3424
3425 static int
event_enable_print(struct seq_file * m,unsigned long ip,struct ftrace_probe_ops * ops,void * data)3426 event_enable_print(struct seq_file *m, unsigned long ip,
3427 struct ftrace_probe_ops *ops, void *data)
3428 {
3429 struct ftrace_func_mapper *mapper = data;
3430 struct event_probe_data *edata;
3431 void **pdata;
3432
3433 pdata = ftrace_func_mapper_find_ip(mapper, ip);
3434
3435 if (WARN_ON_ONCE(!pdata || !*pdata))
3436 return 0;
3437
3438 edata = *pdata;
3439
3440 seq_printf(m, "%ps:", (void *)ip);
3441
3442 seq_printf(m, "%s:%s:%s",
3443 edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
3444 edata->file->event_call->class->system,
3445 trace_event_name(edata->file->event_call));
3446
3447 if (edata->count == -1)
3448 seq_puts(m, ":unlimited\n");
3449 else
3450 seq_printf(m, ":count=%ld\n", edata->count);
3451
3452 return 0;
3453 }
3454
3455 static int
event_enable_init(struct ftrace_probe_ops * ops,struct trace_array * tr,unsigned long ip,void * init_data,void ** data)3456 event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
3457 unsigned long ip, void *init_data, void **data)
3458 {
3459 struct ftrace_func_mapper *mapper = *data;
3460 struct event_probe_data *edata = init_data;
3461 int ret;
3462
3463 if (!mapper) {
3464 mapper = allocate_ftrace_func_mapper();
3465 if (!mapper)
3466 return -ENODEV;
3467 *data = mapper;
3468 }
3469
3470 ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
3471 if (ret < 0)
3472 return ret;
3473
3474 edata->ref++;
3475
3476 return 0;
3477 }
3478
free_probe_data(void * data)3479 static int free_probe_data(void *data)
3480 {
3481 struct event_probe_data *edata = data;
3482
3483 edata->ref--;
3484 if (!edata->ref) {
3485 /* Remove the SOFT_MODE flag */
3486 __ftrace_event_enable_disable(edata->file, 0, 1);
3487 trace_event_put_ref(edata->file->event_call);
3488 kfree(edata);
3489 }
3490 return 0;
3491 }
3492
3493 static void
event_enable_free(struct ftrace_probe_ops * ops,struct trace_array * tr,unsigned long ip,void * data)3494 event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
3495 unsigned long ip, void *data)
3496 {
3497 struct ftrace_func_mapper *mapper = data;
3498 struct event_probe_data *edata;
3499
3500 if (!ip) {
3501 if (!mapper)
3502 return;
3503 free_ftrace_func_mapper(mapper, free_probe_data);
3504 return;
3505 }
3506
3507 edata = ftrace_func_mapper_remove_ip(mapper, ip);
3508
3509 if (WARN_ON_ONCE(!edata))
3510 return;
3511
3512 if (WARN_ON_ONCE(edata->ref <= 0))
3513 return;
3514
3515 free_probe_data(edata);
3516 }
3517
3518 static struct ftrace_probe_ops event_enable_probe_ops = {
3519 .func = event_enable_probe,
3520 .print = event_enable_print,
3521 .init = event_enable_init,
3522 .free = event_enable_free,
3523 };
3524
3525 static struct ftrace_probe_ops event_enable_count_probe_ops = {
3526 .func = event_enable_count_probe,
3527 .print = event_enable_print,
3528 .init = event_enable_init,
3529 .free = event_enable_free,
3530 };
3531
3532 static struct ftrace_probe_ops event_disable_probe_ops = {
3533 .func = event_enable_probe,
3534 .print = event_enable_print,
3535 .init = event_enable_init,
3536 .free = event_enable_free,
3537 };
3538
3539 static struct ftrace_probe_ops event_disable_count_probe_ops = {
3540 .func = event_enable_count_probe,
3541 .print = event_enable_print,
3542 .init = event_enable_init,
3543 .free = event_enable_free,
3544 };
3545
3546 static int
event_enable_func(struct trace_array * tr,struct ftrace_hash * hash,char * glob,char * cmd,char * param,int enabled)3547 event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
3548 char *glob, char *cmd, char *param, int enabled)
3549 {
3550 struct trace_event_file *file;
3551 struct ftrace_probe_ops *ops;
3552 struct event_probe_data *data;
3553 const char *system;
3554 const char *event;
3555 char *number;
3556 bool enable;
3557 int ret;
3558
3559 if (!tr)
3560 return -ENODEV;
3561
3562 /* hash funcs only work with set_ftrace_filter */
3563 if (!enabled || !param)
3564 return -EINVAL;
3565
3566 system = strsep(¶m, ":");
3567 if (!param)
3568 return -EINVAL;
3569
3570 event = strsep(¶m, ":");
3571
3572 mutex_lock(&event_mutex);
3573
3574 ret = -EINVAL;
3575 file = find_event_file(tr, system, event);
3576 if (!file)
3577 goto out;
3578
3579 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
3580
3581 if (enable)
3582 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
3583 else
3584 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
3585
3586 if (glob[0] == '!') {
3587 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
3588 goto out;
3589 }
3590
3591 ret = -ENOMEM;
3592
3593 data = kzalloc(sizeof(*data), GFP_KERNEL);
3594 if (!data)
3595 goto out;
3596
3597 data->enable = enable;
3598 data->count = -1;
3599 data->file = file;
3600
3601 if (!param)
3602 goto out_reg;
3603
3604 number = strsep(¶m, ":");
3605
3606 ret = -EINVAL;
3607 if (!strlen(number))
3608 goto out_free;
3609
3610 /*
3611 * We use the callback data field (which is a pointer)
3612 * as our counter.
3613 */
3614 ret = kstrtoul(number, 0, &data->count);
3615 if (ret)
3616 goto out_free;
3617
3618 out_reg:
3619 /* Don't let event modules unload while probe registered */
3620 ret = trace_event_try_get_ref(file->event_call);
3621 if (!ret) {
3622 ret = -EBUSY;
3623 goto out_free;
3624 }
3625
3626 ret = __ftrace_event_enable_disable(file, 1, 1);
3627 if (ret < 0)
3628 goto out_put;
3629
3630 ret = register_ftrace_function_probe(glob, tr, ops, data);
3631 /*
3632 * The above returns on success the # of functions enabled,
3633 * but if it didn't find any functions it returns zero.
3634 * Consider no functions a failure too.
3635 */
3636 if (!ret) {
3637 ret = -ENOENT;
3638 goto out_disable;
3639 } else if (ret < 0)
3640 goto out_disable;
3641 /* Just return zero, not the number of enabled functions */
3642 ret = 0;
3643 out:
3644 mutex_unlock(&event_mutex);
3645 return ret;
3646
3647 out_disable:
3648 __ftrace_event_enable_disable(file, 0, 1);
3649 out_put:
3650 trace_event_put_ref(file->event_call);
3651 out_free:
3652 kfree(data);
3653 goto out;
3654 }
3655
3656 static struct ftrace_func_command event_enable_cmd = {
3657 .name = ENABLE_EVENT_STR,
3658 .func = event_enable_func,
3659 };
3660
3661 static struct ftrace_func_command event_disable_cmd = {
3662 .name = DISABLE_EVENT_STR,
3663 .func = event_enable_func,
3664 };
3665
register_event_cmds(void)3666 static __init int register_event_cmds(void)
3667 {
3668 int ret;
3669
3670 ret = register_ftrace_command(&event_enable_cmd);
3671 if (WARN_ON(ret < 0))
3672 return ret;
3673 ret = register_ftrace_command(&event_disable_cmd);
3674 if (WARN_ON(ret < 0))
3675 unregister_ftrace_command(&event_enable_cmd);
3676 return ret;
3677 }
3678 #else
register_event_cmds(void)3679 static inline int register_event_cmds(void) { return 0; }
3680 #endif /* CONFIG_DYNAMIC_FTRACE */
3681
3682 /*
3683 * The top level array and trace arrays created by boot-time tracing
3684 * have already had its trace_event_file descriptors created in order
3685 * to allow for early events to be recorded.
3686 * This function is called after the tracefs has been initialized,
3687 * and we now have to create the files associated to the events.
3688 */
__trace_early_add_event_dirs(struct trace_array * tr)3689 static void __trace_early_add_event_dirs(struct trace_array *tr)
3690 {
3691 struct trace_event_file *file;
3692 int ret;
3693
3694
3695 list_for_each_entry(file, &tr->events, list) {
3696 ret = event_create_dir(tr->event_dir, file);
3697 if (ret < 0)
3698 pr_warn("Could not create directory for event %s\n",
3699 trace_event_name(file->event_call));
3700 }
3701 }
3702
3703 /*
3704 * For early boot up, the top trace array and the trace arrays created
3705 * by boot-time tracing require to have a list of events that can be
3706 * enabled. This must be done before the filesystem is set up in order
3707 * to allow events to be traced early.
3708 */
__trace_early_add_events(struct trace_array * tr)3709 void __trace_early_add_events(struct trace_array *tr)
3710 {
3711 struct trace_event_call *call;
3712 int ret;
3713
3714 list_for_each_entry(call, &ftrace_events, list) {
3715 /* Early boot up should not have any modules loaded */
3716 if (!(call->flags & TRACE_EVENT_FL_DYNAMIC) &&
3717 WARN_ON_ONCE(call->module))
3718 continue;
3719
3720 ret = __trace_early_add_new_event(call, tr);
3721 if (ret < 0)
3722 pr_warn("Could not create early event %s\n",
3723 trace_event_name(call));
3724 }
3725 }
3726
3727 /* Remove the event directory structure for a trace directory. */
3728 static void
__trace_remove_event_dirs(struct trace_array * tr)3729 __trace_remove_event_dirs(struct trace_array *tr)
3730 {
3731 struct trace_event_file *file, *next;
3732
3733 list_for_each_entry_safe(file, next, &tr->events, list)
3734 remove_event_file_dir(file);
3735 }
3736
__add_event_to_tracers(struct trace_event_call * call)3737 static void __add_event_to_tracers(struct trace_event_call *call)
3738 {
3739 struct trace_array *tr;
3740
3741 list_for_each_entry(tr, &ftrace_trace_arrays, list)
3742 __trace_add_new_event(call, tr);
3743 }
3744
3745 extern struct trace_event_call *__start_ftrace_events[];
3746 extern struct trace_event_call *__stop_ftrace_events[];
3747
3748 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
3749
setup_trace_event(char * str)3750 static __init int setup_trace_event(char *str)
3751 {
3752 strscpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
3753 ring_buffer_expanded = true;
3754 disable_tracing_selftest("running event tracing");
3755
3756 return 1;
3757 }
3758 __setup("trace_event=", setup_trace_event);
3759
events_callback(const char * name,umode_t * mode,void ** data,const struct file_operations ** fops)3760 static int events_callback(const char *name, umode_t *mode, void **data,
3761 const struct file_operations **fops)
3762 {
3763 if (strcmp(name, "enable") == 0) {
3764 *mode = TRACE_MODE_WRITE;
3765 *fops = &ftrace_tr_enable_fops;
3766 return 1;
3767 }
3768
3769 if (strcmp(name, "header_page") == 0)
3770 *data = ring_buffer_print_page_header;
3771
3772 else if (strcmp(name, "header_event") == 0)
3773 *data = ring_buffer_print_entry_header;
3774
3775 else
3776 return 0;
3777
3778 *mode = TRACE_MODE_READ;
3779 *fops = &ftrace_show_header_fops;
3780 return 1;
3781 }
3782
3783 /* Expects to have event_mutex held when called */
3784 static int
create_event_toplevel_files(struct dentry * parent,struct trace_array * tr)3785 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
3786 {
3787 struct eventfs_inode *e_events;
3788 struct dentry *entry;
3789 int nr_entries;
3790 static struct eventfs_entry events_entries[] = {
3791 {
3792 .name = "enable",
3793 .callback = events_callback,
3794 },
3795 {
3796 .name = "header_page",
3797 .callback = events_callback,
3798 },
3799 {
3800 .name = "header_event",
3801 .callback = events_callback,
3802 },
3803 };
3804
3805 entry = trace_create_file("set_event", TRACE_MODE_WRITE, parent,
3806 tr, &ftrace_set_event_fops);
3807 if (!entry)
3808 return -ENOMEM;
3809
3810 nr_entries = ARRAY_SIZE(events_entries);
3811
3812 e_events = eventfs_create_events_dir("events", parent, events_entries,
3813 nr_entries, tr);
3814 if (IS_ERR(e_events)) {
3815 pr_warn("Could not create tracefs 'events' directory\n");
3816 return -ENOMEM;
3817 }
3818
3819 /* There are not as crucial, just warn if they are not created */
3820
3821 trace_create_file("set_event_pid", TRACE_MODE_WRITE, parent,
3822 tr, &ftrace_set_event_pid_fops);
3823
3824 trace_create_file("set_event_notrace_pid",
3825 TRACE_MODE_WRITE, parent, tr,
3826 &ftrace_set_event_notrace_pid_fops);
3827
3828 tr->event_dir = e_events;
3829
3830 return 0;
3831 }
3832
3833 /**
3834 * event_trace_add_tracer - add a instance of a trace_array to events
3835 * @parent: The parent dentry to place the files/directories for events in
3836 * @tr: The trace array associated with these events
3837 *
3838 * When a new instance is created, it needs to set up its events
3839 * directory, as well as other files associated with events. It also
3840 * creates the event hierarchy in the @parent/events directory.
3841 *
3842 * Returns 0 on success.
3843 *
3844 * Must be called with event_mutex held.
3845 */
event_trace_add_tracer(struct dentry * parent,struct trace_array * tr)3846 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
3847 {
3848 int ret;
3849
3850 lockdep_assert_held(&event_mutex);
3851
3852 ret = create_event_toplevel_files(parent, tr);
3853 if (ret)
3854 goto out;
3855
3856 down_write(&trace_event_sem);
3857 /* If tr already has the event list, it is initialized in early boot. */
3858 if (unlikely(!list_empty(&tr->events)))
3859 __trace_early_add_event_dirs(tr);
3860 else
3861 __trace_add_event_dirs(tr);
3862 up_write(&trace_event_sem);
3863
3864 out:
3865 return ret;
3866 }
3867
3868 /*
3869 * The top trace array already had its file descriptors created.
3870 * Now the files themselves need to be created.
3871 */
3872 static __init int
early_event_add_tracer(struct dentry * parent,struct trace_array * tr)3873 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
3874 {
3875 int ret;
3876
3877 mutex_lock(&event_mutex);
3878
3879 ret = create_event_toplevel_files(parent, tr);
3880 if (ret)
3881 goto out_unlock;
3882
3883 down_write(&trace_event_sem);
3884 __trace_early_add_event_dirs(tr);
3885 up_write(&trace_event_sem);
3886
3887 out_unlock:
3888 mutex_unlock(&event_mutex);
3889
3890 return ret;
3891 }
3892
3893 /* Must be called with event_mutex held */
event_trace_del_tracer(struct trace_array * tr)3894 int event_trace_del_tracer(struct trace_array *tr)
3895 {
3896 lockdep_assert_held(&event_mutex);
3897
3898 /* Disable any event triggers and associated soft-disabled events */
3899 clear_event_triggers(tr);
3900
3901 /* Clear the pid list */
3902 __ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
3903
3904 /* Disable any running events */
3905 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3906
3907 /* Make sure no more events are being executed */
3908 tracepoint_synchronize_unregister();
3909
3910 down_write(&trace_event_sem);
3911 __trace_remove_event_dirs(tr);
3912 eventfs_remove_events_dir(tr->event_dir);
3913 up_write(&trace_event_sem);
3914
3915 tr->event_dir = NULL;
3916
3917 return 0;
3918 }
3919
event_trace_memsetup(void)3920 static __init int event_trace_memsetup(void)
3921 {
3922 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3923 file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3924 return 0;
3925 }
3926
3927 __init void
early_enable_events(struct trace_array * tr,char * buf,bool disable_first)3928 early_enable_events(struct trace_array *tr, char *buf, bool disable_first)
3929 {
3930 char *token;
3931 int ret;
3932
3933 while (true) {
3934 token = strsep(&buf, ",");
3935
3936 if (!token)
3937 break;
3938
3939 if (*token) {
3940 /* Restarting syscalls requires that we stop them first */
3941 if (disable_first)
3942 ftrace_set_clr_event(tr, token, 0);
3943
3944 ret = ftrace_set_clr_event(tr, token, 1);
3945 if (ret)
3946 pr_warn("Failed to enable trace event: %s\n", token);
3947 }
3948
3949 /* Put back the comma to allow this to be called again */
3950 if (buf)
3951 *(buf - 1) = ',';
3952 }
3953 }
3954
event_trace_enable(void)3955 static __init int event_trace_enable(void)
3956 {
3957 struct trace_array *tr = top_trace_array();
3958 struct trace_event_call **iter, *call;
3959 int ret;
3960
3961 if (!tr)
3962 return -ENODEV;
3963
3964 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3965
3966 call = *iter;
3967 ret = event_init(call);
3968 if (!ret)
3969 list_add(&call->list, &ftrace_events);
3970 }
3971
3972 register_trigger_cmds();
3973
3974 /*
3975 * We need the top trace array to have a working set of trace
3976 * points at early init, before the debug files and directories
3977 * are created. Create the file entries now, and attach them
3978 * to the actual file dentries later.
3979 */
3980 __trace_early_add_events(tr);
3981
3982 early_enable_events(tr, bootup_event_buf, false);
3983
3984 trace_printk_start_comm();
3985
3986 register_event_cmds();
3987
3988
3989 return 0;
3990 }
3991
3992 /*
3993 * event_trace_enable() is called from trace_event_init() first to
3994 * initialize events and perhaps start any events that are on the
3995 * command line. Unfortunately, there are some events that will not
3996 * start this early, like the system call tracepoints that need
3997 * to set the %SYSCALL_WORK_SYSCALL_TRACEPOINT flag of pid 1. But
3998 * event_trace_enable() is called before pid 1 starts, and this flag
3999 * is never set, making the syscall tracepoint never get reached, but
4000 * the event is enabled regardless (and not doing anything).
4001 */
event_trace_enable_again(void)4002 static __init int event_trace_enable_again(void)
4003 {
4004 struct trace_array *tr;
4005
4006 tr = top_trace_array();
4007 if (!tr)
4008 return -ENODEV;
4009
4010 early_enable_events(tr, bootup_event_buf, true);
4011
4012 return 0;
4013 }
4014
4015 early_initcall(event_trace_enable_again);
4016
4017 /* Init fields which doesn't related to the tracefs */
event_trace_init_fields(void)4018 static __init int event_trace_init_fields(void)
4019 {
4020 if (trace_define_generic_fields())
4021 pr_warn("tracing: Failed to allocated generic fields");
4022
4023 if (trace_define_common_fields())
4024 pr_warn("tracing: Failed to allocate common fields");
4025
4026 return 0;
4027 }
4028
event_trace_init(void)4029 __init int event_trace_init(void)
4030 {
4031 struct trace_array *tr;
4032 int ret;
4033
4034 tr = top_trace_array();
4035 if (!tr)
4036 return -ENODEV;
4037
4038 trace_create_file("available_events", TRACE_MODE_READ,
4039 NULL, tr, &ftrace_avail_fops);
4040
4041 ret = early_event_add_tracer(NULL, tr);
4042 if (ret)
4043 return ret;
4044
4045 #ifdef CONFIG_MODULES
4046 ret = register_module_notifier(&trace_module_nb);
4047 if (ret)
4048 pr_warn("Failed to register trace events module notifier\n");
4049 #endif
4050
4051 eventdir_initialized = true;
4052
4053 return 0;
4054 }
4055
trace_event_init(void)4056 void __init trace_event_init(void)
4057 {
4058 event_trace_memsetup();
4059 init_ftrace_syscalls();
4060 event_trace_enable();
4061 event_trace_init_fields();
4062 }
4063
4064 #ifdef CONFIG_EVENT_TRACE_STARTUP_TEST
4065
4066 static DEFINE_SPINLOCK(test_spinlock);
4067 static DEFINE_SPINLOCK(test_spinlock_irq);
4068 static DEFINE_MUTEX(test_mutex);
4069
test_work(struct work_struct * dummy)4070 static __init void test_work(struct work_struct *dummy)
4071 {
4072 spin_lock(&test_spinlock);
4073 spin_lock_irq(&test_spinlock_irq);
4074 udelay(1);
4075 spin_unlock_irq(&test_spinlock_irq);
4076 spin_unlock(&test_spinlock);
4077
4078 mutex_lock(&test_mutex);
4079 msleep(1);
4080 mutex_unlock(&test_mutex);
4081 }
4082
event_test_thread(void * unused)4083 static __init int event_test_thread(void *unused)
4084 {
4085 void *test_malloc;
4086
4087 test_malloc = kmalloc(1234, GFP_KERNEL);
4088 if (!test_malloc)
4089 pr_info("failed to kmalloc\n");
4090
4091 schedule_on_each_cpu(test_work);
4092
4093 kfree(test_malloc);
4094
4095 set_current_state(TASK_INTERRUPTIBLE);
4096 while (!kthread_should_stop()) {
4097 schedule();
4098 set_current_state(TASK_INTERRUPTIBLE);
4099 }
4100 __set_current_state(TASK_RUNNING);
4101
4102 return 0;
4103 }
4104
4105 /*
4106 * Do various things that may trigger events.
4107 */
event_test_stuff(void)4108 static __init void event_test_stuff(void)
4109 {
4110 struct task_struct *test_thread;
4111
4112 test_thread = kthread_run(event_test_thread, NULL, "test-events");
4113 msleep(1);
4114 kthread_stop(test_thread);
4115 }
4116
4117 /*
4118 * For every trace event defined, we will test each trace point separately,
4119 * and then by groups, and finally all trace points.
4120 */
event_trace_self_tests(void)4121 static __init void event_trace_self_tests(void)
4122 {
4123 struct trace_subsystem_dir *dir;
4124 struct trace_event_file *file;
4125 struct trace_event_call *call;
4126 struct event_subsystem *system;
4127 struct trace_array *tr;
4128 int ret;
4129
4130 tr = top_trace_array();
4131 if (!tr)
4132 return;
4133
4134 pr_info("Running tests on trace events:\n");
4135
4136 list_for_each_entry(file, &tr->events, list) {
4137
4138 call = file->event_call;
4139
4140 /* Only test those that have a probe */
4141 if (!call->class || !call->class->probe)
4142 continue;
4143
4144 /*
4145 * Testing syscall events here is pretty useless, but
4146 * we still do it if configured. But this is time consuming.
4147 * What we really need is a user thread to perform the
4148 * syscalls as we test.
4149 */
4150 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
4151 if (call->class->system &&
4152 strcmp(call->class->system, "syscalls") == 0)
4153 continue;
4154 #endif
4155
4156 pr_info("Testing event %s: ", trace_event_name(call));
4157
4158 /*
4159 * If an event is already enabled, someone is using
4160 * it and the self test should not be on.
4161 */
4162 if (file->flags & EVENT_FILE_FL_ENABLED) {
4163 pr_warn("Enabled event during self test!\n");
4164 WARN_ON_ONCE(1);
4165 continue;
4166 }
4167
4168 ftrace_event_enable_disable(file, 1);
4169 event_test_stuff();
4170 ftrace_event_enable_disable(file, 0);
4171
4172 pr_cont("OK\n");
4173 }
4174
4175 /* Now test at the sub system level */
4176
4177 pr_info("Running tests on trace event systems:\n");
4178
4179 list_for_each_entry(dir, &tr->systems, list) {
4180
4181 system = dir->subsystem;
4182
4183 /* the ftrace system is special, skip it */
4184 if (strcmp(system->name, "ftrace") == 0)
4185 continue;
4186
4187 pr_info("Testing event system %s: ", system->name);
4188
4189 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
4190 if (WARN_ON_ONCE(ret)) {
4191 pr_warn("error enabling system %s\n",
4192 system->name);
4193 continue;
4194 }
4195
4196 event_test_stuff();
4197
4198 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
4199 if (WARN_ON_ONCE(ret)) {
4200 pr_warn("error disabling system %s\n",
4201 system->name);
4202 continue;
4203 }
4204
4205 pr_cont("OK\n");
4206 }
4207
4208 /* Test with all events enabled */
4209
4210 pr_info("Running tests on all trace events:\n");
4211 pr_info("Testing all events: ");
4212
4213 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
4214 if (WARN_ON_ONCE(ret)) {
4215 pr_warn("error enabling all events\n");
4216 return;
4217 }
4218
4219 event_test_stuff();
4220
4221 /* reset sysname */
4222 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
4223 if (WARN_ON_ONCE(ret)) {
4224 pr_warn("error disabling all events\n");
4225 return;
4226 }
4227
4228 pr_cont("OK\n");
4229 }
4230
4231 #ifdef CONFIG_FUNCTION_TRACER
4232
4233 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
4234
4235 static struct trace_event_file event_trace_file __initdata;
4236
4237 static void __init
function_test_events_call(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * op,struct ftrace_regs * regs)4238 function_test_events_call(unsigned long ip, unsigned long parent_ip,
4239 struct ftrace_ops *op, struct ftrace_regs *regs)
4240 {
4241 struct trace_buffer *buffer;
4242 struct ring_buffer_event *event;
4243 struct ftrace_entry *entry;
4244 unsigned int trace_ctx;
4245 long disabled;
4246 int cpu;
4247
4248 trace_ctx = tracing_gen_ctx();
4249 preempt_disable_notrace();
4250 cpu = raw_smp_processor_id();
4251 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
4252
4253 if (disabled != 1)
4254 goto out;
4255
4256 event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
4257 TRACE_FN, sizeof(*entry),
4258 trace_ctx);
4259 if (!event)
4260 goto out;
4261 entry = ring_buffer_event_data(event);
4262 entry->ip = ip;
4263 entry->parent_ip = parent_ip;
4264
4265 event_trigger_unlock_commit(&event_trace_file, buffer, event,
4266 entry, trace_ctx);
4267 out:
4268 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
4269 preempt_enable_notrace();
4270 }
4271
4272 static struct ftrace_ops trace_ops __initdata =
4273 {
4274 .func = function_test_events_call,
4275 };
4276
event_trace_self_test_with_function(void)4277 static __init void event_trace_self_test_with_function(void)
4278 {
4279 int ret;
4280
4281 event_trace_file.tr = top_trace_array();
4282 if (WARN_ON(!event_trace_file.tr))
4283 return;
4284
4285 ret = register_ftrace_function(&trace_ops);
4286 if (WARN_ON(ret < 0)) {
4287 pr_info("Failed to enable function tracer for event tests\n");
4288 return;
4289 }
4290 pr_info("Running tests again, along with the function tracer\n");
4291 event_trace_self_tests();
4292 unregister_ftrace_function(&trace_ops);
4293 }
4294 #else
event_trace_self_test_with_function(void)4295 static __init void event_trace_self_test_with_function(void)
4296 {
4297 }
4298 #endif
4299
event_trace_self_tests_init(void)4300 static __init int event_trace_self_tests_init(void)
4301 {
4302 if (!tracing_selftest_disabled) {
4303 event_trace_self_tests();
4304 event_trace_self_test_with_function();
4305 }
4306
4307 return 0;
4308 }
4309
4310 late_initcall(event_trace_self_tests_init);
4311
4312 #endif
4313