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TOMOYO Linux Cross Reference
Linux/kernel/trace/trace_events.c

Version: ~ [ linux-5.2-rc6 ] ~ [ linux-5.1.15 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.56 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.130 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.183 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.183 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.69 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /*
  2  * event tracer
  3  *
  4  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
  5  *
  6  *  - Added format output of fields of the trace point.
  7  *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
  8  *
  9  */
 10 
 11 #include <linux/workqueue.h>
 12 #include <linux/spinlock.h>
 13 #include <linux/kthread.h>
 14 #include <linux/debugfs.h>
 15 #include <linux/uaccess.h>
 16 #include <linux/module.h>
 17 #include <linux/ctype.h>
 18 #include <linux/slab.h>
 19 #include <linux/delay.h>
 20 
 21 #include <asm/setup.h>
 22 
 23 #include "trace_output.h"
 24 
 25 #undef TRACE_SYSTEM
 26 #define TRACE_SYSTEM "TRACE_SYSTEM"
 27 
 28 DEFINE_MUTEX(event_mutex);
 29 
 30 DEFINE_MUTEX(event_storage_mutex);
 31 EXPORT_SYMBOL_GPL(event_storage_mutex);
 32 
 33 char event_storage[EVENT_STORAGE_SIZE];
 34 EXPORT_SYMBOL_GPL(event_storage);
 35 
 36 LIST_HEAD(ftrace_events);
 37 LIST_HEAD(ftrace_common_fields);
 38 
 39 struct list_head *
 40 trace_get_fields(struct ftrace_event_call *event_call)
 41 {
 42         if (!event_call->class->get_fields)
 43                 return &event_call->class->fields;
 44         return event_call->class->get_fields(event_call);
 45 }
 46 
 47 static int __trace_define_field(struct list_head *head, const char *type,
 48                                 const char *name, int offset, int size,
 49                                 int is_signed, int filter_type)
 50 {
 51         struct ftrace_event_field *field;
 52 
 53         field = kzalloc(sizeof(*field), GFP_KERNEL);
 54         if (!field)
 55                 goto err;
 56 
 57         field->name = kstrdup(name, GFP_KERNEL);
 58         if (!field->name)
 59                 goto err;
 60 
 61         field->type = kstrdup(type, GFP_KERNEL);
 62         if (!field->type)
 63                 goto err;
 64 
 65         if (filter_type == FILTER_OTHER)
 66                 field->filter_type = filter_assign_type(type);
 67         else
 68                 field->filter_type = filter_type;
 69 
 70         field->offset = offset;
 71         field->size = size;
 72         field->is_signed = is_signed;
 73 
 74         list_add(&field->link, head);
 75 
 76         return 0;
 77 
 78 err:
 79         if (field)
 80                 kfree(field->name);
 81         kfree(field);
 82 
 83         return -ENOMEM;
 84 }
 85 
 86 int trace_define_field(struct ftrace_event_call *call, const char *type,
 87                        const char *name, int offset, int size, int is_signed,
 88                        int filter_type)
 89 {
 90         struct list_head *head;
 91 
 92         if (WARN_ON(!call->class))
 93                 return 0;
 94 
 95         head = trace_get_fields(call);
 96         return __trace_define_field(head, type, name, offset, size,
 97                                     is_signed, filter_type);
 98 }
 99 EXPORT_SYMBOL_GPL(trace_define_field);
100 
101 #define __common_field(type, item)                                      \
102         ret = __trace_define_field(&ftrace_common_fields, #type,        \
103                                    "common_" #item,                     \
104                                    offsetof(typeof(ent), item),         \
105                                    sizeof(ent.item),                    \
106                                    is_signed_type(type), FILTER_OTHER); \
107         if (ret)                                                        \
108                 return ret;
109 
110 static int trace_define_common_fields(void)
111 {
112         int ret;
113         struct trace_entry ent;
114 
115         __common_field(unsigned short, type);
116         __common_field(unsigned char, flags);
117         __common_field(unsigned char, preempt_count);
118         __common_field(int, pid);
119         __common_field(int, padding);
120 
121         return ret;
122 }
123 
124 void trace_destroy_fields(struct ftrace_event_call *call)
125 {
126         struct ftrace_event_field *field, *next;
127         struct list_head *head;
128 
129         head = trace_get_fields(call);
130         list_for_each_entry_safe(field, next, head, link) {
131                 list_del(&field->link);
132                 kfree(field->type);
133                 kfree(field->name);
134                 kfree(field);
135         }
136 }
137 
138 int trace_event_raw_init(struct ftrace_event_call *call)
139 {
140         int id;
141 
142         id = register_ftrace_event(&call->event);
143         if (!id)
144                 return -ENODEV;
145 
146         return 0;
147 }
148 EXPORT_SYMBOL_GPL(trace_event_raw_init);
149 
150 int ftrace_event_reg(struct ftrace_event_call *call,
151                      enum trace_reg type, void *data)
152 {
153         switch (type) {
154         case TRACE_REG_REGISTER:
155                 return tracepoint_probe_register(call->name,
156                                                  call->class->probe,
157                                                  call);
158         case TRACE_REG_UNREGISTER:
159                 tracepoint_probe_unregister(call->name,
160                                             call->class->probe,
161                                             call);
162                 return 0;
163 
164 #ifdef CONFIG_PERF_EVENTS
165         case TRACE_REG_PERF_REGISTER:
166                 return tracepoint_probe_register(call->name,
167                                                  call->class->perf_probe,
168                                                  call);
169         case TRACE_REG_PERF_UNREGISTER:
170                 tracepoint_probe_unregister(call->name,
171                                             call->class->perf_probe,
172                                             call);
173                 return 0;
174         case TRACE_REG_PERF_OPEN:
175         case TRACE_REG_PERF_CLOSE:
176         case TRACE_REG_PERF_ADD:
177         case TRACE_REG_PERF_DEL:
178                 return 0;
179 #endif
180         }
181         return 0;
182 }
183 EXPORT_SYMBOL_GPL(ftrace_event_reg);
184 
185 void trace_event_enable_cmd_record(bool enable)
186 {
187         struct ftrace_event_call *call;
188 
189         mutex_lock(&event_mutex);
190         list_for_each_entry(call, &ftrace_events, list) {
191                 if (!(call->flags & TRACE_EVENT_FL_ENABLED))
192                         continue;
193 
194                 if (enable) {
195                         tracing_start_cmdline_record();
196                         call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
197                 } else {
198                         tracing_stop_cmdline_record();
199                         call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
200                 }
201         }
202         mutex_unlock(&event_mutex);
203 }
204 
205 static int ftrace_event_enable_disable(struct ftrace_event_call *call,
206                                         int enable)
207 {
208         int ret = 0;
209 
210         switch (enable) {
211         case 0:
212                 if (call->flags & TRACE_EVENT_FL_ENABLED) {
213                         call->flags &= ~TRACE_EVENT_FL_ENABLED;
214                         if (call->flags & TRACE_EVENT_FL_RECORDED_CMD) {
215                                 tracing_stop_cmdline_record();
216                                 call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
217                         }
218                         call->class->reg(call, TRACE_REG_UNREGISTER, NULL);
219                 }
220                 break;
221         case 1:
222                 if (!(call->flags & TRACE_EVENT_FL_ENABLED)) {
223                         if (trace_flags & TRACE_ITER_RECORD_CMD) {
224                                 tracing_start_cmdline_record();
225                                 call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
226                         }
227                         ret = call->class->reg(call, TRACE_REG_REGISTER, NULL);
228                         if (ret) {
229                                 tracing_stop_cmdline_record();
230                                 pr_info("event trace: Could not enable event "
231                                         "%s\n", call->name);
232                                 break;
233                         }
234                         call->flags |= TRACE_EVENT_FL_ENABLED;
235                 }
236                 break;
237         }
238 
239         return ret;
240 }
241 
242 static void ftrace_clear_events(void)
243 {
244         struct ftrace_event_call *call;
245 
246         mutex_lock(&event_mutex);
247         list_for_each_entry(call, &ftrace_events, list) {
248                 ftrace_event_enable_disable(call, 0);
249         }
250         mutex_unlock(&event_mutex);
251 }
252 
253 static void __put_system(struct event_subsystem *system)
254 {
255         struct event_filter *filter = system->filter;
256 
257         WARN_ON_ONCE(system->ref_count == 0);
258         if (--system->ref_count)
259                 return;
260 
261         if (filter) {
262                 kfree(filter->filter_string);
263                 kfree(filter);
264         }
265         kfree(system->name);
266         kfree(system);
267 }
268 
269 static void __get_system(struct event_subsystem *system)
270 {
271         WARN_ON_ONCE(system->ref_count == 0);
272         system->ref_count++;
273 }
274 
275 static void put_system(struct event_subsystem *system)
276 {
277         mutex_lock(&event_mutex);
278         __put_system(system);
279         mutex_unlock(&event_mutex);
280 }
281 
282 /*
283  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
284  */
285 static int __ftrace_set_clr_event(const char *match, const char *sub,
286                                   const char *event, int set)
287 {
288         struct ftrace_event_call *call;
289         int ret = -EINVAL;
290 
291         mutex_lock(&event_mutex);
292         list_for_each_entry(call, &ftrace_events, list) {
293 
294                 if (!call->name || !call->class || !call->class->reg)
295                         continue;
296 
297                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
298                         continue;
299 
300                 if (match &&
301                     strcmp(match, call->name) != 0 &&
302                     strcmp(match, call->class->system) != 0)
303                         continue;
304 
305                 if (sub && strcmp(sub, call->class->system) != 0)
306                         continue;
307 
308                 if (event && strcmp(event, call->name) != 0)
309                         continue;
310 
311                 ftrace_event_enable_disable(call, set);
312 
313                 ret = 0;
314         }
315         mutex_unlock(&event_mutex);
316 
317         return ret;
318 }
319 
320 static int ftrace_set_clr_event(char *buf, int set)
321 {
322         char *event = NULL, *sub = NULL, *match;
323 
324         /*
325          * The buf format can be <subsystem>:<event-name>
326          *  *:<event-name> means any event by that name.
327          *  :<event-name> is the same.
328          *
329          *  <subsystem>:* means all events in that subsystem
330          *  <subsystem>: means the same.
331          *
332          *  <name> (no ':') means all events in a subsystem with
333          *  the name <name> or any event that matches <name>
334          */
335 
336         match = strsep(&buf, ":");
337         if (buf) {
338                 sub = match;
339                 event = buf;
340                 match = NULL;
341 
342                 if (!strlen(sub) || strcmp(sub, "*") == 0)
343                         sub = NULL;
344                 if (!strlen(event) || strcmp(event, "*") == 0)
345                         event = NULL;
346         }
347 
348         return __ftrace_set_clr_event(match, sub, event, set);
349 }
350 
351 /**
352  * trace_set_clr_event - enable or disable an event
353  * @system: system name to match (NULL for any system)
354  * @event: event name to match (NULL for all events, within system)
355  * @set: 1 to enable, 0 to disable
356  *
357  * This is a way for other parts of the kernel to enable or disable
358  * event recording.
359  *
360  * Returns 0 on success, -EINVAL if the parameters do not match any
361  * registered events.
362  */
363 int trace_set_clr_event(const char *system, const char *event, int set)
364 {
365         return __ftrace_set_clr_event(NULL, system, event, set);
366 }
367 EXPORT_SYMBOL_GPL(trace_set_clr_event);
368 
369 /* 128 should be much more than enough */
370 #define EVENT_BUF_SIZE          127
371 
372 static ssize_t
373 ftrace_event_write(struct file *file, const char __user *ubuf,
374                    size_t cnt, loff_t *ppos)
375 {
376         struct trace_parser parser;
377         ssize_t read, ret;
378 
379         if (!cnt)
380                 return 0;
381 
382         ret = tracing_update_buffers();
383         if (ret < 0)
384                 return ret;
385 
386         if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
387                 return -ENOMEM;
388 
389         read = trace_get_user(&parser, ubuf, cnt, ppos);
390 
391         if (read >= 0 && trace_parser_loaded((&parser))) {
392                 int set = 1;
393 
394                 if (*parser.buffer == '!')
395                         set = 0;
396 
397                 parser.buffer[parser.idx] = 0;
398 
399                 ret = ftrace_set_clr_event(parser.buffer + !set, set);
400                 if (ret)
401                         goto out_put;
402         }
403 
404         ret = read;
405 
406  out_put:
407         trace_parser_put(&parser);
408 
409         return ret;
410 }
411 
412 static void *
413 t_next(struct seq_file *m, void *v, loff_t *pos)
414 {
415         struct ftrace_event_call *call = v;
416 
417         (*pos)++;
418 
419         list_for_each_entry_continue(call, &ftrace_events, list) {
420                 /*
421                  * The ftrace subsystem is for showing formats only.
422                  * They can not be enabled or disabled via the event files.
423                  */
424                 if (call->class && call->class->reg)
425                         return call;
426         }
427 
428         return NULL;
429 }
430 
431 static void *t_start(struct seq_file *m, loff_t *pos)
432 {
433         struct ftrace_event_call *call;
434         loff_t l;
435 
436         mutex_lock(&event_mutex);
437 
438         call = list_entry(&ftrace_events, struct ftrace_event_call, list);
439         for (l = 0; l <= *pos; ) {
440                 call = t_next(m, call, &l);
441                 if (!call)
442                         break;
443         }
444         return call;
445 }
446 
447 static void *
448 s_next(struct seq_file *m, void *v, loff_t *pos)
449 {
450         struct ftrace_event_call *call = v;
451 
452         (*pos)++;
453 
454         list_for_each_entry_continue(call, &ftrace_events, list) {
455                 if (call->flags & TRACE_EVENT_FL_ENABLED)
456                         return call;
457         }
458 
459         return NULL;
460 }
461 
462 static void *s_start(struct seq_file *m, loff_t *pos)
463 {
464         struct ftrace_event_call *call;
465         loff_t l;
466 
467         mutex_lock(&event_mutex);
468 
469         call = list_entry(&ftrace_events, struct ftrace_event_call, list);
470         for (l = 0; l <= *pos; ) {
471                 call = s_next(m, call, &l);
472                 if (!call)
473                         break;
474         }
475         return call;
476 }
477 
478 static int t_show(struct seq_file *m, void *v)
479 {
480         struct ftrace_event_call *call = v;
481 
482         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
483                 seq_printf(m, "%s:", call->class->system);
484         seq_printf(m, "%s\n", call->name);
485 
486         return 0;
487 }
488 
489 static void t_stop(struct seq_file *m, void *p)
490 {
491         mutex_unlock(&event_mutex);
492 }
493 
494 static ssize_t
495 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
496                   loff_t *ppos)
497 {
498         struct ftrace_event_call *call = filp->private_data;
499         char *buf;
500 
501         if (call->flags & TRACE_EVENT_FL_ENABLED)
502                 buf = "1\n";
503         else
504                 buf = "\n";
505 
506         return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
507 }
508 
509 static ssize_t
510 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
511                    loff_t *ppos)
512 {
513         struct ftrace_event_call *call = filp->private_data;
514         unsigned long val;
515         int ret;
516 
517         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
518         if (ret)
519                 return ret;
520 
521         ret = tracing_update_buffers();
522         if (ret < 0)
523                 return ret;
524 
525         switch (val) {
526         case 0:
527         case 1:
528                 mutex_lock(&event_mutex);
529                 ret = ftrace_event_enable_disable(call, val);
530                 mutex_unlock(&event_mutex);
531                 break;
532 
533         default:
534                 return -EINVAL;
535         }
536 
537         *ppos += cnt;
538 
539         return ret ? ret : cnt;
540 }
541 
542 static ssize_t
543 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
544                    loff_t *ppos)
545 {
546         const char set_to_char[4] = { '?', '', '1', 'X' };
547         struct event_subsystem *system = filp->private_data;
548         struct ftrace_event_call *call;
549         char buf[2];
550         int set = 0;
551         int ret;
552 
553         mutex_lock(&event_mutex);
554         list_for_each_entry(call, &ftrace_events, list) {
555                 if (!call->name || !call->class || !call->class->reg)
556                         continue;
557 
558                 if (system && strcmp(call->class->system, system->name) != 0)
559                         continue;
560 
561                 /*
562                  * We need to find out if all the events are set
563                  * or if all events or cleared, or if we have
564                  * a mixture.
565                  */
566                 set |= (1 << !!(call->flags & TRACE_EVENT_FL_ENABLED));
567 
568                 /*
569                  * If we have a mixture, no need to look further.
570                  */
571                 if (set == 3)
572                         break;
573         }
574         mutex_unlock(&event_mutex);
575 
576         buf[0] = set_to_char[set];
577         buf[1] = '\n';
578 
579         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
580 
581         return ret;
582 }
583 
584 static ssize_t
585 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
586                     loff_t *ppos)
587 {
588         struct event_subsystem *system = filp->private_data;
589         const char *name = NULL;
590         unsigned long val;
591         ssize_t ret;
592 
593         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
594         if (ret)
595                 return ret;
596 
597         ret = tracing_update_buffers();
598         if (ret < 0)
599                 return ret;
600 
601         if (val != 0 && val != 1)
602                 return -EINVAL;
603 
604         /*
605          * Opening of "enable" adds a ref count to system,
606          * so the name is safe to use.
607          */
608         if (system)
609                 name = system->name;
610 
611         ret = __ftrace_set_clr_event(NULL, name, NULL, val);
612         if (ret)
613                 goto out;
614 
615         ret = cnt;
616 
617 out:
618         *ppos += cnt;
619 
620         return ret;
621 }
622 
623 enum {
624         FORMAT_HEADER           = 1,
625         FORMAT_FIELD_SEPERATOR  = 2,
626         FORMAT_PRINTFMT         = 3,
627 };
628 
629 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
630 {
631         struct ftrace_event_call *call = m->private;
632         struct ftrace_event_field *field;
633         struct list_head *common_head = &ftrace_common_fields;
634         struct list_head *head = trace_get_fields(call);
635 
636         (*pos)++;
637 
638         switch ((unsigned long)v) {
639         case FORMAT_HEADER:
640                 if (unlikely(list_empty(common_head)))
641                         return NULL;
642 
643                 field = list_entry(common_head->prev,
644                                    struct ftrace_event_field, link);
645                 return field;
646 
647         case FORMAT_FIELD_SEPERATOR:
648                 if (unlikely(list_empty(head)))
649                         return NULL;
650 
651                 field = list_entry(head->prev, struct ftrace_event_field, link);
652                 return field;
653 
654         case FORMAT_PRINTFMT:
655                 /* all done */
656                 return NULL;
657         }
658 
659         field = v;
660         if (field->link.prev == common_head)
661                 return (void *)FORMAT_FIELD_SEPERATOR;
662         else if (field->link.prev == head)
663                 return (void *)FORMAT_PRINTFMT;
664 
665         field = list_entry(field->link.prev, struct ftrace_event_field, link);
666 
667         return field;
668 }
669 
670 static void *f_start(struct seq_file *m, loff_t *pos)
671 {
672         loff_t l = 0;
673         void *p;
674 
675         /* Start by showing the header */
676         if (!*pos)
677                 return (void *)FORMAT_HEADER;
678 
679         p = (void *)FORMAT_HEADER;
680         do {
681                 p = f_next(m, p, &l);
682         } while (p && l < *pos);
683 
684         return p;
685 }
686 
687 static int f_show(struct seq_file *m, void *v)
688 {
689         struct ftrace_event_call *call = m->private;
690         struct ftrace_event_field *field;
691         const char *array_descriptor;
692 
693         switch ((unsigned long)v) {
694         case FORMAT_HEADER:
695                 seq_printf(m, "name: %s\n", call->name);
696                 seq_printf(m, "ID: %d\n", call->event.type);
697                 seq_printf(m, "format:\n");
698                 return 0;
699 
700         case FORMAT_FIELD_SEPERATOR:
701                 seq_putc(m, '\n');
702                 return 0;
703 
704         case FORMAT_PRINTFMT:
705                 seq_printf(m, "\nprint fmt: %s\n",
706                            call->print_fmt);
707                 return 0;
708         }
709 
710         field = v;
711 
712         /*
713          * Smartly shows the array type(except dynamic array).
714          * Normal:
715          *      field:TYPE VAR
716          * If TYPE := TYPE[LEN], it is shown:
717          *      field:TYPE VAR[LEN]
718          */
719         array_descriptor = strchr(field->type, '[');
720 
721         if (!strncmp(field->type, "__data_loc", 10))
722                 array_descriptor = NULL;
723 
724         if (!array_descriptor)
725                 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
726                            field->type, field->name, field->offset,
727                            field->size, !!field->is_signed);
728         else
729                 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
730                            (int)(array_descriptor - field->type),
731                            field->type, field->name,
732                            array_descriptor, field->offset,
733                            field->size, !!field->is_signed);
734 
735         return 0;
736 }
737 
738 static void f_stop(struct seq_file *m, void *p)
739 {
740 }
741 
742 static const struct seq_operations trace_format_seq_ops = {
743         .start          = f_start,
744         .next           = f_next,
745         .stop           = f_stop,
746         .show           = f_show,
747 };
748 
749 static int trace_format_open(struct inode *inode, struct file *file)
750 {
751         struct ftrace_event_call *call = inode->i_private;
752         struct seq_file *m;
753         int ret;
754 
755         ret = seq_open(file, &trace_format_seq_ops);
756         if (ret < 0)
757                 return ret;
758 
759         m = file->private_data;
760         m->private = call;
761 
762         return 0;
763 }
764 
765 static ssize_t
766 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
767 {
768         struct ftrace_event_call *call = filp->private_data;
769         struct trace_seq *s;
770         int r;
771 
772         if (*ppos)
773                 return 0;
774 
775         s = kmalloc(sizeof(*s), GFP_KERNEL);
776         if (!s)
777                 return -ENOMEM;
778 
779         trace_seq_init(s);
780         trace_seq_printf(s, "%d\n", call->event.type);
781 
782         r = simple_read_from_buffer(ubuf, cnt, ppos,
783                                     s->buffer, s->len);
784         kfree(s);
785         return r;
786 }
787 
788 static ssize_t
789 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
790                   loff_t *ppos)
791 {
792         struct ftrace_event_call *call = filp->private_data;
793         struct trace_seq *s;
794         int r;
795 
796         if (*ppos)
797                 return 0;
798 
799         s = kmalloc(sizeof(*s), GFP_KERNEL);
800         if (!s)
801                 return -ENOMEM;
802 
803         trace_seq_init(s);
804 
805         print_event_filter(call, s);
806         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
807 
808         kfree(s);
809 
810         return r;
811 }
812 
813 static ssize_t
814 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
815                    loff_t *ppos)
816 {
817         struct ftrace_event_call *call = filp->private_data;
818         char *buf;
819         int err;
820 
821         if (cnt >= PAGE_SIZE)
822                 return -EINVAL;
823 
824         buf = (char *)__get_free_page(GFP_TEMPORARY);
825         if (!buf)
826                 return -ENOMEM;
827 
828         if (copy_from_user(buf, ubuf, cnt)) {
829                 free_page((unsigned long) buf);
830                 return -EFAULT;
831         }
832         buf[cnt] = '\0';
833 
834         err = apply_event_filter(call, buf);
835         free_page((unsigned long) buf);
836         if (err < 0)
837                 return err;
838 
839         *ppos += cnt;
840 
841         return cnt;
842 }
843 
844 static LIST_HEAD(event_subsystems);
845 
846 static int subsystem_open(struct inode *inode, struct file *filp)
847 {
848         struct event_subsystem *system = NULL;
849         int ret;
850 
851         if (!inode->i_private)
852                 goto skip_search;
853 
854         /* Make sure the system still exists */
855         mutex_lock(&event_mutex);
856         list_for_each_entry(system, &event_subsystems, list) {
857                 if (system == inode->i_private) {
858                         /* Don't open systems with no events */
859                         if (!system->nr_events) {
860                                 system = NULL;
861                                 break;
862                         }
863                         __get_system(system);
864                         break;
865                 }
866         }
867         mutex_unlock(&event_mutex);
868 
869         if (system != inode->i_private)
870                 return -ENODEV;
871 
872  skip_search:
873         ret = tracing_open_generic(inode, filp);
874         if (ret < 0 && system)
875                 put_system(system);
876 
877         return ret;
878 }
879 
880 static int subsystem_release(struct inode *inode, struct file *file)
881 {
882         struct event_subsystem *system = inode->i_private;
883 
884         if (system)
885                 put_system(system);
886 
887         return 0;
888 }
889 
890 static ssize_t
891 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
892                       loff_t *ppos)
893 {
894         struct event_subsystem *system = filp->private_data;
895         struct trace_seq *s;
896         int r;
897 
898         if (*ppos)
899                 return 0;
900 
901         s = kmalloc(sizeof(*s), GFP_KERNEL);
902         if (!s)
903                 return -ENOMEM;
904 
905         trace_seq_init(s);
906 
907         print_subsystem_event_filter(system, s);
908         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
909 
910         kfree(s);
911 
912         return r;
913 }
914 
915 static ssize_t
916 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
917                        loff_t *ppos)
918 {
919         struct event_subsystem *system = filp->private_data;
920         char *buf;
921         int err;
922 
923         if (cnt >= PAGE_SIZE)
924                 return -EINVAL;
925 
926         buf = (char *)__get_free_page(GFP_TEMPORARY);
927         if (!buf)
928                 return -ENOMEM;
929 
930         if (copy_from_user(buf, ubuf, cnt)) {
931                 free_page((unsigned long) buf);
932                 return -EFAULT;
933         }
934         buf[cnt] = '\0';
935 
936         err = apply_subsystem_event_filter(system, buf);
937         free_page((unsigned long) buf);
938         if (err < 0)
939                 return err;
940 
941         *ppos += cnt;
942 
943         return cnt;
944 }
945 
946 static ssize_t
947 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
948 {
949         int (*func)(struct trace_seq *s) = filp->private_data;
950         struct trace_seq *s;
951         int r;
952 
953         if (*ppos)
954                 return 0;
955 
956         s = kmalloc(sizeof(*s), GFP_KERNEL);
957         if (!s)
958                 return -ENOMEM;
959 
960         trace_seq_init(s);
961 
962         func(s);
963         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
964 
965         kfree(s);
966 
967         return r;
968 }
969 
970 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
971 static int ftrace_event_set_open(struct inode *inode, struct file *file);
972 
973 static const struct seq_operations show_event_seq_ops = {
974         .start = t_start,
975         .next = t_next,
976         .show = t_show,
977         .stop = t_stop,
978 };
979 
980 static const struct seq_operations show_set_event_seq_ops = {
981         .start = s_start,
982         .next = s_next,
983         .show = t_show,
984         .stop = t_stop,
985 };
986 
987 static const struct file_operations ftrace_avail_fops = {
988         .open = ftrace_event_avail_open,
989         .read = seq_read,
990         .llseek = seq_lseek,
991         .release = seq_release,
992 };
993 
994 static const struct file_operations ftrace_set_event_fops = {
995         .open = ftrace_event_set_open,
996         .read = seq_read,
997         .write = ftrace_event_write,
998         .llseek = seq_lseek,
999         .release = seq_release,
1000 };
1001 
1002 static const struct file_operations ftrace_enable_fops = {
1003         .open = tracing_open_generic,
1004         .read = event_enable_read,
1005         .write = event_enable_write,
1006         .llseek = default_llseek,
1007 };
1008 
1009 static const struct file_operations ftrace_event_format_fops = {
1010         .open = trace_format_open,
1011         .read = seq_read,
1012         .llseek = seq_lseek,
1013         .release = seq_release,
1014 };
1015 
1016 static const struct file_operations ftrace_event_id_fops = {
1017         .open = tracing_open_generic,
1018         .read = event_id_read,
1019         .llseek = default_llseek,
1020 };
1021 
1022 static const struct file_operations ftrace_event_filter_fops = {
1023         .open = tracing_open_generic,
1024         .read = event_filter_read,
1025         .write = event_filter_write,
1026         .llseek = default_llseek,
1027 };
1028 
1029 static const struct file_operations ftrace_subsystem_filter_fops = {
1030         .open = subsystem_open,
1031         .read = subsystem_filter_read,
1032         .write = subsystem_filter_write,
1033         .llseek = default_llseek,
1034         .release = subsystem_release,
1035 };
1036 
1037 static const struct file_operations ftrace_system_enable_fops = {
1038         .open = subsystem_open,
1039         .read = system_enable_read,
1040         .write = system_enable_write,
1041         .llseek = default_llseek,
1042         .release = subsystem_release,
1043 };
1044 
1045 static const struct file_operations ftrace_show_header_fops = {
1046         .open = tracing_open_generic,
1047         .read = show_header,
1048         .llseek = default_llseek,
1049 };
1050 
1051 static struct dentry *event_trace_events_dir(void)
1052 {
1053         static struct dentry *d_tracer;
1054         static struct dentry *d_events;
1055 
1056         if (d_events)
1057                 return d_events;
1058 
1059         d_tracer = tracing_init_dentry();
1060         if (!d_tracer)
1061                 return NULL;
1062 
1063         d_events = debugfs_create_dir("events", d_tracer);
1064         if (!d_events)
1065                 pr_warning("Could not create debugfs "
1066                            "'events' directory\n");
1067 
1068         return d_events;
1069 }
1070 
1071 static int
1072 ftrace_event_avail_open(struct inode *inode, struct file *file)
1073 {
1074         const struct seq_operations *seq_ops = &show_event_seq_ops;
1075 
1076         return seq_open(file, seq_ops);
1077 }
1078 
1079 static int
1080 ftrace_event_set_open(struct inode *inode, struct file *file)
1081 {
1082         const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1083 
1084         if ((file->f_mode & FMODE_WRITE) &&
1085             (file->f_flags & O_TRUNC))
1086                 ftrace_clear_events();
1087 
1088         return seq_open(file, seq_ops);
1089 }
1090 
1091 static struct dentry *
1092 event_subsystem_dir(const char *name, struct dentry *d_events)
1093 {
1094         struct event_subsystem *system;
1095         struct dentry *entry;
1096 
1097         /* First see if we did not already create this dir */
1098         list_for_each_entry(system, &event_subsystems, list) {
1099                 if (strcmp(system->name, name) == 0) {
1100                         system->nr_events++;
1101                         return system->entry;
1102                 }
1103         }
1104 
1105         /* need to create new entry */
1106         system = kmalloc(sizeof(*system), GFP_KERNEL);
1107         if (!system) {
1108                 pr_warning("No memory to create event subsystem %s\n",
1109                            name);
1110                 return d_events;
1111         }
1112 
1113         system->entry = debugfs_create_dir(name, d_events);
1114         if (!system->entry) {
1115                 pr_warning("Could not create event subsystem %s\n",
1116                            name);
1117                 kfree(system);
1118                 return d_events;
1119         }
1120 
1121         system->nr_events = 1;
1122         system->ref_count = 1;
1123         system->name = kstrdup(name, GFP_KERNEL);
1124         if (!system->name) {
1125                 debugfs_remove(system->entry);
1126                 kfree(system);
1127                 return d_events;
1128         }
1129 
1130         list_add(&system->list, &event_subsystems);
1131 
1132         system->filter = NULL;
1133 
1134         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1135         if (!system->filter) {
1136                 pr_warning("Could not allocate filter for subsystem "
1137                            "'%s'\n", name);
1138                 return system->entry;
1139         }
1140 
1141         entry = debugfs_create_file("filter", 0644, system->entry, system,
1142                                     &ftrace_subsystem_filter_fops);
1143         if (!entry) {
1144                 kfree(system->filter);
1145                 system->filter = NULL;
1146                 pr_warning("Could not create debugfs "
1147                            "'%s/filter' entry\n", name);
1148         }
1149 
1150         trace_create_file("enable", 0644, system->entry, system,
1151                           &ftrace_system_enable_fops);
1152 
1153         return system->entry;
1154 }
1155 
1156 static int
1157 event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
1158                  const struct file_operations *id,
1159                  const struct file_operations *enable,
1160                  const struct file_operations *filter,
1161                  const struct file_operations *format)
1162 {
1163         struct list_head *head;
1164         int ret;
1165 
1166         /*
1167          * If the trace point header did not define TRACE_SYSTEM
1168          * then the system would be called "TRACE_SYSTEM".
1169          */
1170         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1171                 d_events = event_subsystem_dir(call->class->system, d_events);
1172 
1173         call->dir = debugfs_create_dir(call->name, d_events);
1174         if (!call->dir) {
1175                 pr_warning("Could not create debugfs "
1176                            "'%s' directory\n", call->name);
1177                 return -1;
1178         }
1179 
1180         if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1181                 trace_create_file("enable", 0644, call->dir, call,
1182                                   enable);
1183 
1184 #ifdef CONFIG_PERF_EVENTS
1185         if (call->event.type && call->class->reg)
1186                 trace_create_file("id", 0444, call->dir, call,
1187                                   id);
1188 #endif
1189 
1190         /*
1191          * Other events may have the same class. Only update
1192          * the fields if they are not already defined.
1193          */
1194         head = trace_get_fields(call);
1195         if (list_empty(head)) {
1196                 ret = call->class->define_fields(call);
1197                 if (ret < 0) {
1198                         pr_warning("Could not initialize trace point"
1199                                    " events/%s\n", call->name);
1200                         return ret;
1201                 }
1202         }
1203         trace_create_file("filter", 0644, call->dir, call,
1204                           filter);
1205 
1206         trace_create_file("format", 0444, call->dir, call,
1207                           format);
1208 
1209         return 0;
1210 }
1211 
1212 static void event_remove(struct ftrace_event_call *call)
1213 {
1214         ftrace_event_enable_disable(call, 0);
1215         if (call->event.funcs)
1216                 __unregister_ftrace_event(&call->event);
1217         list_del(&call->list);
1218 }
1219 
1220 static int event_init(struct ftrace_event_call *call)
1221 {
1222         int ret = 0;
1223 
1224         if (WARN_ON(!call->name))
1225                 return -EINVAL;
1226 
1227         if (call->class->raw_init) {
1228                 ret = call->class->raw_init(call);
1229                 if (ret < 0 && ret != -ENOSYS)
1230                         pr_warn("Could not initialize trace events/%s\n",
1231                                 call->name);
1232         }
1233 
1234         return ret;
1235 }
1236 
1237 static int
1238 __trace_add_event_call(struct ftrace_event_call *call, struct module *mod,
1239                        const struct file_operations *id,
1240                        const struct file_operations *enable,
1241                        const struct file_operations *filter,
1242                        const struct file_operations *format)
1243 {
1244         struct dentry *d_events;
1245         int ret;
1246 
1247         ret = event_init(call);
1248         if (ret < 0)
1249                 return ret;
1250 
1251         d_events = event_trace_events_dir();
1252         if (!d_events)
1253                 return -ENOENT;
1254 
1255         ret = event_create_dir(call, d_events, id, enable, filter, format);
1256         if (!ret)
1257                 list_add(&call->list, &ftrace_events);
1258         call->mod = mod;
1259 
1260         return ret;
1261 }
1262 
1263 /* Add an additional event_call dynamically */
1264 int trace_add_event_call(struct ftrace_event_call *call)
1265 {
1266         int ret;
1267         mutex_lock(&event_mutex);
1268         ret = __trace_add_event_call(call, NULL, &ftrace_event_id_fops,
1269                                      &ftrace_enable_fops,
1270                                      &ftrace_event_filter_fops,
1271                                      &ftrace_event_format_fops);
1272         mutex_unlock(&event_mutex);
1273         return ret;
1274 }
1275 
1276 static void remove_subsystem_dir(const char *name)
1277 {
1278         struct event_subsystem *system;
1279 
1280         if (strcmp(name, TRACE_SYSTEM) == 0)
1281                 return;
1282 
1283         list_for_each_entry(system, &event_subsystems, list) {
1284                 if (strcmp(system->name, name) == 0) {
1285                         if (!--system->nr_events) {
1286                                 debugfs_remove_recursive(system->entry);
1287                                 list_del(&system->list);
1288                                 __put_system(system);
1289                         }
1290                         break;
1291                 }
1292         }
1293 }
1294 
1295 /*
1296  * Must be called under locking both of event_mutex and trace_event_mutex.
1297  */
1298 static void __trace_remove_event_call(struct ftrace_event_call *call)
1299 {
1300         event_remove(call);
1301         trace_destroy_fields(call);
1302         destroy_preds(call);
1303         debugfs_remove_recursive(call->dir);
1304         remove_subsystem_dir(call->class->system);
1305 }
1306 
1307 /* Remove an event_call */
1308 void trace_remove_event_call(struct ftrace_event_call *call)
1309 {
1310         mutex_lock(&event_mutex);
1311         down_write(&trace_event_mutex);
1312         __trace_remove_event_call(call);
1313         up_write(&trace_event_mutex);
1314         mutex_unlock(&event_mutex);
1315 }
1316 
1317 #define for_each_event(event, start, end)                       \
1318         for (event = start;                                     \
1319              (unsigned long)event < (unsigned long)end;         \
1320              event++)
1321 
1322 #ifdef CONFIG_MODULES
1323 
1324 static LIST_HEAD(ftrace_module_file_list);
1325 
1326 /*
1327  * Modules must own their file_operations to keep up with
1328  * reference counting.
1329  */
1330 struct ftrace_module_file_ops {
1331         struct list_head                list;
1332         struct module                   *mod;
1333         struct file_operations          id;
1334         struct file_operations          enable;
1335         struct file_operations          format;
1336         struct file_operations          filter;
1337 };
1338 
1339 static struct ftrace_module_file_ops *
1340 trace_create_file_ops(struct module *mod)
1341 {
1342         struct ftrace_module_file_ops *file_ops;
1343 
1344         /*
1345          * This is a bit of a PITA. To allow for correct reference
1346          * counting, modules must "own" their file_operations.
1347          * To do this, we allocate the file operations that will be
1348          * used in the event directory.
1349          */
1350 
1351         file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1352         if (!file_ops)
1353                 return NULL;
1354 
1355         file_ops->mod = mod;
1356 
1357         file_ops->id = ftrace_event_id_fops;
1358         file_ops->id.owner = mod;
1359 
1360         file_ops->enable = ftrace_enable_fops;
1361         file_ops->enable.owner = mod;
1362 
1363         file_ops->filter = ftrace_event_filter_fops;
1364         file_ops->filter.owner = mod;
1365 
1366         file_ops->format = ftrace_event_format_fops;
1367         file_ops->format.owner = mod;
1368 
1369         list_add(&file_ops->list, &ftrace_module_file_list);
1370 
1371         return file_ops;
1372 }
1373 
1374 static void trace_module_add_events(struct module *mod)
1375 {
1376         struct ftrace_module_file_ops *file_ops = NULL;
1377         struct ftrace_event_call **call, **start, **end;
1378 
1379         start = mod->trace_events;
1380         end = mod->trace_events + mod->num_trace_events;
1381 
1382         if (start == end)
1383                 return;
1384 
1385         file_ops = trace_create_file_ops(mod);
1386         if (!file_ops)
1387                 return;
1388 
1389         for_each_event(call, start, end) {
1390                 __trace_add_event_call(*call, mod,
1391                                        &file_ops->id, &file_ops->enable,
1392                                        &file_ops->filter, &file_ops->format);
1393         }
1394 }
1395 
1396 static void trace_module_remove_events(struct module *mod)
1397 {
1398         struct ftrace_module_file_ops *file_ops;
1399         struct ftrace_event_call *call, *p;
1400         bool found = false;
1401 
1402         down_write(&trace_event_mutex);
1403         list_for_each_entry_safe(call, p, &ftrace_events, list) {
1404                 if (call->mod == mod) {
1405                         found = true;
1406                         __trace_remove_event_call(call);
1407                 }
1408         }
1409 
1410         /* Now free the file_operations */
1411         list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1412                 if (file_ops->mod == mod)
1413                         break;
1414         }
1415         if (&file_ops->list != &ftrace_module_file_list) {
1416                 list_del(&file_ops->list);
1417                 kfree(file_ops);
1418         }
1419 
1420         /*
1421          * It is safest to reset the ring buffer if the module being unloaded
1422          * registered any events.
1423          */
1424         if (found)
1425                 tracing_reset_current_online_cpus();
1426         up_write(&trace_event_mutex);
1427 }
1428 
1429 static int trace_module_notify(struct notifier_block *self,
1430                                unsigned long val, void *data)
1431 {
1432         struct module *mod = data;
1433 
1434         mutex_lock(&event_mutex);
1435         switch (val) {
1436         case MODULE_STATE_COMING:
1437                 trace_module_add_events(mod);
1438                 break;
1439         case MODULE_STATE_GOING:
1440                 trace_module_remove_events(mod);
1441                 break;
1442         }
1443         mutex_unlock(&event_mutex);
1444 
1445         return 0;
1446 }
1447 #else
1448 static int trace_module_notify(struct notifier_block *self,
1449                                unsigned long val, void *data)
1450 {
1451         return 0;
1452 }
1453 #endif /* CONFIG_MODULES */
1454 
1455 static struct notifier_block trace_module_nb = {
1456         .notifier_call = trace_module_notify,
1457         .priority = 0,
1458 };
1459 
1460 extern struct ftrace_event_call *__start_ftrace_events[];
1461 extern struct ftrace_event_call *__stop_ftrace_events[];
1462 
1463 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
1464 
1465 static __init int setup_trace_event(char *str)
1466 {
1467         strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
1468         ring_buffer_expanded = 1;
1469         tracing_selftest_disabled = 1;
1470 
1471         return 1;
1472 }
1473 __setup("trace_event=", setup_trace_event);
1474 
1475 static __init int event_trace_enable(void)
1476 {
1477         struct ftrace_event_call **iter, *call;
1478         char *buf = bootup_event_buf;
1479         char *token;
1480         int ret;
1481 
1482         for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
1483 
1484                 call = *iter;
1485                 ret = event_init(call);
1486                 if (!ret)
1487                         list_add(&call->list, &ftrace_events);
1488         }
1489 
1490         while (true) {
1491                 token = strsep(&buf, ",");
1492 
1493                 if (!token)
1494                         break;
1495                 if (!*token)
1496                         continue;
1497 
1498                 ret = ftrace_set_clr_event(token, 1);
1499                 if (ret)
1500                         pr_warn("Failed to enable trace event: %s\n", token);
1501         }
1502 
1503         trace_printk_start_comm();
1504 
1505         return 0;
1506 }
1507 
1508 static __init int event_trace_init(void)
1509 {
1510         struct ftrace_event_call *call;
1511         struct dentry *d_tracer;
1512         struct dentry *entry;
1513         struct dentry *d_events;
1514         int ret;
1515 
1516         d_tracer = tracing_init_dentry();
1517         if (!d_tracer)
1518                 return 0;
1519 
1520         entry = debugfs_create_file("available_events", 0444, d_tracer,
1521                                     NULL, &ftrace_avail_fops);
1522         if (!entry)
1523                 pr_warning("Could not create debugfs "
1524                            "'available_events' entry\n");
1525 
1526         entry = debugfs_create_file("set_event", 0644, d_tracer,
1527                                     NULL, &ftrace_set_event_fops);
1528         if (!entry)
1529                 pr_warning("Could not create debugfs "
1530                            "'set_event' entry\n");
1531 
1532         d_events = event_trace_events_dir();
1533         if (!d_events)
1534                 return 0;
1535 
1536         /* ring buffer internal formats */
1537         trace_create_file("header_page", 0444, d_events,
1538                           ring_buffer_print_page_header,
1539                           &ftrace_show_header_fops);
1540 
1541         trace_create_file("header_event", 0444, d_events,
1542                           ring_buffer_print_entry_header,
1543                           &ftrace_show_header_fops);
1544 
1545         trace_create_file("enable", 0644, d_events,
1546                           NULL, &ftrace_system_enable_fops);
1547 
1548         if (trace_define_common_fields())
1549                 pr_warning("tracing: Failed to allocate common fields");
1550 
1551         /*
1552          * Early initialization already enabled ftrace event.
1553          * Now it's only necessary to create the event directory.
1554          */
1555         list_for_each_entry(call, &ftrace_events, list) {
1556 
1557                 ret = event_create_dir(call, d_events,
1558                                        &ftrace_event_id_fops,
1559                                        &ftrace_enable_fops,
1560                                        &ftrace_event_filter_fops,
1561                                        &ftrace_event_format_fops);
1562                 if (ret < 0)
1563                         event_remove(call);
1564         }
1565 
1566         ret = register_module_notifier(&trace_module_nb);
1567         if (ret)
1568                 pr_warning("Failed to register trace events module notifier\n");
1569 
1570         return 0;
1571 }
1572 core_initcall(event_trace_enable);
1573 fs_initcall(event_trace_init);
1574 
1575 #ifdef CONFIG_FTRACE_STARTUP_TEST
1576 
1577 static DEFINE_SPINLOCK(test_spinlock);
1578 static DEFINE_SPINLOCK(test_spinlock_irq);
1579 static DEFINE_MUTEX(test_mutex);
1580 
1581 static __init void test_work(struct work_struct *dummy)
1582 {
1583         spin_lock(&test_spinlock);
1584         spin_lock_irq(&test_spinlock_irq);
1585         udelay(1);
1586         spin_unlock_irq(&test_spinlock_irq);
1587         spin_unlock(&test_spinlock);
1588 
1589         mutex_lock(&test_mutex);
1590         msleep(1);
1591         mutex_unlock(&test_mutex);
1592 }
1593 
1594 static __init int event_test_thread(void *unused)
1595 {
1596         void *test_malloc;
1597 
1598         test_malloc = kmalloc(1234, GFP_KERNEL);
1599         if (!test_malloc)
1600                 pr_info("failed to kmalloc\n");
1601 
1602         schedule_on_each_cpu(test_work);
1603 
1604         kfree(test_malloc);
1605 
1606         set_current_state(TASK_INTERRUPTIBLE);
1607         while (!kthread_should_stop())
1608                 schedule();
1609 
1610         return 0;
1611 }
1612 
1613 /*
1614  * Do various things that may trigger events.
1615  */
1616 static __init void event_test_stuff(void)
1617 {
1618         struct task_struct *test_thread;
1619 
1620         test_thread = kthread_run(event_test_thread, NULL, "test-events");
1621         msleep(1);
1622         kthread_stop(test_thread);
1623 }
1624 
1625 /*
1626  * For every trace event defined, we will test each trace point separately,
1627  * and then by groups, and finally all trace points.
1628  */
1629 static __init void event_trace_self_tests(void)
1630 {
1631         struct ftrace_event_call *call;
1632         struct event_subsystem *system;
1633         int ret;
1634 
1635         pr_info("Running tests on trace events:\n");
1636 
1637         list_for_each_entry(call, &ftrace_events, list) {
1638 
1639                 /* Only test those that have a probe */
1640                 if (!call->class || !call->class->probe)
1641                         continue;
1642 
1643 /*
1644  * Testing syscall events here is pretty useless, but
1645  * we still do it if configured. But this is time consuming.
1646  * What we really need is a user thread to perform the
1647  * syscalls as we test.
1648  */
1649 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
1650                 if (call->class->system &&
1651                     strcmp(call->class->system, "syscalls") == 0)
1652                         continue;
1653 #endif
1654 
1655                 pr_info("Testing event %s: ", call->name);
1656 
1657                 /*
1658                  * If an event is already enabled, someone is using
1659                  * it and the self test should not be on.
1660                  */
1661                 if (call->flags & TRACE_EVENT_FL_ENABLED) {
1662                         pr_warning("Enabled event during self test!\n");
1663                         WARN_ON_ONCE(1);
1664                         continue;
1665                 }
1666 
1667                 ftrace_event_enable_disable(call, 1);
1668                 event_test_stuff();
1669                 ftrace_event_enable_disable(call, 0);
1670 
1671                 pr_cont("OK\n");
1672         }
1673 
1674         /* Now test at the sub system level */
1675 
1676         pr_info("Running tests on trace event systems:\n");
1677 
1678         list_for_each_entry(system, &event_subsystems, list) {
1679 
1680                 /* the ftrace system is special, skip it */
1681                 if (strcmp(system->name, "ftrace") == 0)
1682                         continue;
1683 
1684                 pr_info("Testing event system %s: ", system->name);
1685 
1686                 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
1687                 if (WARN_ON_ONCE(ret)) {
1688                         pr_warning("error enabling system %s\n",
1689                                    system->name);
1690                         continue;
1691                 }
1692 
1693                 event_test_stuff();
1694 
1695                 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
1696                 if (WARN_ON_ONCE(ret)) {
1697                         pr_warning("error disabling system %s\n",
1698                                    system->name);
1699                         continue;
1700                 }
1701 
1702                 pr_cont("OK\n");
1703         }
1704 
1705         /* Test with all events enabled */
1706 
1707         pr_info("Running tests on all trace events:\n");
1708         pr_info("Testing all events: ");
1709 
1710         ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
1711         if (WARN_ON_ONCE(ret)) {
1712                 pr_warning("error enabling all events\n");
1713                 return;
1714         }
1715 
1716         event_test_stuff();
1717 
1718         /* reset sysname */
1719         ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
1720         if (WARN_ON_ONCE(ret)) {
1721                 pr_warning("error disabling all events\n");
1722                 return;
1723         }
1724 
1725         pr_cont("OK\n");
1726 }
1727 
1728 #ifdef CONFIG_FUNCTION_TRACER
1729 
1730 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
1731 
1732 static void
1733 function_test_events_call(unsigned long ip, unsigned long parent_ip,
1734                           struct ftrace_ops *op, struct pt_regs *pt_regs)
1735 {
1736         struct ring_buffer_event *event;
1737         struct ring_buffer *buffer;
1738         struct ftrace_entry *entry;
1739         unsigned long flags;
1740         long disabled;
1741         int cpu;
1742         int pc;
1743 
1744         pc = preempt_count();
1745         preempt_disable_notrace();
1746         cpu = raw_smp_processor_id();
1747         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
1748 
1749         if (disabled != 1)
1750                 goto out;
1751 
1752         local_save_flags(flags);
1753 
1754         event = trace_current_buffer_lock_reserve(&buffer,
1755                                                   TRACE_FN, sizeof(*entry),
1756                                                   flags, pc);
1757         if (!event)
1758                 goto out;
1759         entry   = ring_buffer_event_data(event);
1760         entry->ip                       = ip;
1761         entry->parent_ip                = parent_ip;
1762 
1763         trace_buffer_unlock_commit(buffer, event, flags, pc);
1764 
1765  out:
1766         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
1767         preempt_enable_notrace();
1768 }
1769 
1770 static struct ftrace_ops trace_ops __initdata  =
1771 {
1772         .func = function_test_events_call,
1773         .flags = FTRACE_OPS_FL_RECURSION_SAFE,
1774 };
1775 
1776 static __init void event_trace_self_test_with_function(void)
1777 {
1778         int ret;
1779         ret = register_ftrace_function(&trace_ops);
1780         if (WARN_ON(ret < 0)) {
1781                 pr_info("Failed to enable function tracer for event tests\n");
1782                 return;
1783         }
1784         pr_info("Running tests again, along with the function tracer\n");
1785         event_trace_self_tests();
1786         unregister_ftrace_function(&trace_ops);
1787 }
1788 #else
1789 static __init void event_trace_self_test_with_function(void)
1790 {
1791 }
1792 #endif
1793 
1794 static __init int event_trace_self_tests_init(void)
1795 {
1796         if (!tracing_selftest_disabled) {
1797                 event_trace_self_tests();
1798                 event_trace_self_test_with_function();
1799         }
1800 
1801         return 0;
1802 }
1803 
1804 late_initcall(event_trace_self_tests_init);
1805 
1806 #endif
1807 

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