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

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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 int
495 ftrace_event_seq_open(struct inode *inode, struct file *file)
496 {
497         const struct seq_operations *seq_ops;
498 
499         if ((file->f_mode & FMODE_WRITE) &&
500             (file->f_flags & O_TRUNC))
501                 ftrace_clear_events();
502 
503         seq_ops = inode->i_private;
504         return seq_open(file, seq_ops);
505 }
506 
507 static ssize_t
508 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
509                   loff_t *ppos)
510 {
511         struct ftrace_event_call *call = filp->private_data;
512         char *buf;
513 
514         if (call->flags & TRACE_EVENT_FL_ENABLED)
515                 buf = "1\n";
516         else
517                 buf = "\n";
518 
519         return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
520 }
521 
522 static ssize_t
523 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
524                    loff_t *ppos)
525 {
526         struct ftrace_event_call *call = filp->private_data;
527         unsigned long val;
528         int ret;
529 
530         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
531         if (ret)
532                 return ret;
533 
534         ret = tracing_update_buffers();
535         if (ret < 0)
536                 return ret;
537 
538         switch (val) {
539         case 0:
540         case 1:
541                 mutex_lock(&event_mutex);
542                 ret = ftrace_event_enable_disable(call, val);
543                 mutex_unlock(&event_mutex);
544                 break;
545 
546         default:
547                 return -EINVAL;
548         }
549 
550         *ppos += cnt;
551 
552         return ret ? ret : cnt;
553 }
554 
555 static ssize_t
556 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
557                    loff_t *ppos)
558 {
559         const char set_to_char[4] = { '?', '', '1', 'X' };
560         struct event_subsystem *system = filp->private_data;
561         struct ftrace_event_call *call;
562         char buf[2];
563         int set = 0;
564         int ret;
565 
566         mutex_lock(&event_mutex);
567         list_for_each_entry(call, &ftrace_events, list) {
568                 if (!call->name || !call->class || !call->class->reg)
569                         continue;
570 
571                 if (system && strcmp(call->class->system, system->name) != 0)
572                         continue;
573 
574                 /*
575                  * We need to find out if all the events are set
576                  * or if all events or cleared, or if we have
577                  * a mixture.
578                  */
579                 set |= (1 << !!(call->flags & TRACE_EVENT_FL_ENABLED));
580 
581                 /*
582                  * If we have a mixture, no need to look further.
583                  */
584                 if (set == 3)
585                         break;
586         }
587         mutex_unlock(&event_mutex);
588 
589         buf[0] = set_to_char[set];
590         buf[1] = '\n';
591 
592         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
593 
594         return ret;
595 }
596 
597 static ssize_t
598 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
599                     loff_t *ppos)
600 {
601         struct event_subsystem *system = filp->private_data;
602         const char *name = NULL;
603         unsigned long val;
604         ssize_t ret;
605 
606         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
607         if (ret)
608                 return ret;
609 
610         ret = tracing_update_buffers();
611         if (ret < 0)
612                 return ret;
613 
614         if (val != 0 && val != 1)
615                 return -EINVAL;
616 
617         /*
618          * Opening of "enable" adds a ref count to system,
619          * so the name is safe to use.
620          */
621         if (system)
622                 name = system->name;
623 
624         ret = __ftrace_set_clr_event(NULL, name, NULL, val);
625         if (ret)
626                 goto out;
627 
628         ret = cnt;
629 
630 out:
631         *ppos += cnt;
632 
633         return ret;
634 }
635 
636 enum {
637         FORMAT_HEADER           = 1,
638         FORMAT_FIELD_SEPERATOR  = 2,
639         FORMAT_PRINTFMT         = 3,
640 };
641 
642 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
643 {
644         struct ftrace_event_call *call = m->private;
645         struct ftrace_event_field *field;
646         struct list_head *common_head = &ftrace_common_fields;
647         struct list_head *head = trace_get_fields(call);
648 
649         (*pos)++;
650 
651         switch ((unsigned long)v) {
652         case FORMAT_HEADER:
653                 if (unlikely(list_empty(common_head)))
654                         return NULL;
655 
656                 field = list_entry(common_head->prev,
657                                    struct ftrace_event_field, link);
658                 return field;
659 
660         case FORMAT_FIELD_SEPERATOR:
661                 if (unlikely(list_empty(head)))
662                         return NULL;
663 
664                 field = list_entry(head->prev, struct ftrace_event_field, link);
665                 return field;
666 
667         case FORMAT_PRINTFMT:
668                 /* all done */
669                 return NULL;
670         }
671 
672         field = v;
673         if (field->link.prev == common_head)
674                 return (void *)FORMAT_FIELD_SEPERATOR;
675         else if (field->link.prev == head)
676                 return (void *)FORMAT_PRINTFMT;
677 
678         field = list_entry(field->link.prev, struct ftrace_event_field, link);
679 
680         return field;
681 }
682 
683 static void *f_start(struct seq_file *m, loff_t *pos)
684 {
685         loff_t l = 0;
686         void *p;
687 
688         /* Start by showing the header */
689         if (!*pos)
690                 return (void *)FORMAT_HEADER;
691 
692         p = (void *)FORMAT_HEADER;
693         do {
694                 p = f_next(m, p, &l);
695         } while (p && l < *pos);
696 
697         return p;
698 }
699 
700 static int f_show(struct seq_file *m, void *v)
701 {
702         struct ftrace_event_call *call = m->private;
703         struct ftrace_event_field *field;
704         const char *array_descriptor;
705 
706         switch ((unsigned long)v) {
707         case FORMAT_HEADER:
708                 seq_printf(m, "name: %s\n", call->name);
709                 seq_printf(m, "ID: %d\n", call->event.type);
710                 seq_printf(m, "format:\n");
711                 return 0;
712 
713         case FORMAT_FIELD_SEPERATOR:
714                 seq_putc(m, '\n');
715                 return 0;
716 
717         case FORMAT_PRINTFMT:
718                 seq_printf(m, "\nprint fmt: %s\n",
719                            call->print_fmt);
720                 return 0;
721         }
722 
723         field = v;
724 
725         /*
726          * Smartly shows the array type(except dynamic array).
727          * Normal:
728          *      field:TYPE VAR
729          * If TYPE := TYPE[LEN], it is shown:
730          *      field:TYPE VAR[LEN]
731          */
732         array_descriptor = strchr(field->type, '[');
733 
734         if (!strncmp(field->type, "__data_loc", 10))
735                 array_descriptor = NULL;
736 
737         if (!array_descriptor)
738                 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
739                            field->type, field->name, field->offset,
740                            field->size, !!field->is_signed);
741         else
742                 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
743                            (int)(array_descriptor - field->type),
744                            field->type, field->name,
745                            array_descriptor, field->offset,
746                            field->size, !!field->is_signed);
747 
748         return 0;
749 }
750 
751 static void f_stop(struct seq_file *m, void *p)
752 {
753 }
754 
755 static const struct seq_operations trace_format_seq_ops = {
756         .start          = f_start,
757         .next           = f_next,
758         .stop           = f_stop,
759         .show           = f_show,
760 };
761 
762 static int trace_format_open(struct inode *inode, struct file *file)
763 {
764         struct ftrace_event_call *call = inode->i_private;
765         struct seq_file *m;
766         int ret;
767 
768         ret = seq_open(file, &trace_format_seq_ops);
769         if (ret < 0)
770                 return ret;
771 
772         m = file->private_data;
773         m->private = call;
774 
775         return 0;
776 }
777 
778 static ssize_t
779 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
780 {
781         struct ftrace_event_call *call = filp->private_data;
782         struct trace_seq *s;
783         int r;
784 
785         if (*ppos)
786                 return 0;
787 
788         s = kmalloc(sizeof(*s), GFP_KERNEL);
789         if (!s)
790                 return -ENOMEM;
791 
792         trace_seq_init(s);
793         trace_seq_printf(s, "%d\n", call->event.type);
794 
795         r = simple_read_from_buffer(ubuf, cnt, ppos,
796                                     s->buffer, s->len);
797         kfree(s);
798         return r;
799 }
800 
801 static ssize_t
802 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
803                   loff_t *ppos)
804 {
805         struct ftrace_event_call *call = filp->private_data;
806         struct trace_seq *s;
807         int r;
808 
809         if (*ppos)
810                 return 0;
811 
812         s = kmalloc(sizeof(*s), GFP_KERNEL);
813         if (!s)
814                 return -ENOMEM;
815 
816         trace_seq_init(s);
817 
818         print_event_filter(call, s);
819         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
820 
821         kfree(s);
822 
823         return r;
824 }
825 
826 static ssize_t
827 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
828                    loff_t *ppos)
829 {
830         struct ftrace_event_call *call = filp->private_data;
831         char *buf;
832         int err;
833 
834         if (cnt >= PAGE_SIZE)
835                 return -EINVAL;
836 
837         buf = (char *)__get_free_page(GFP_TEMPORARY);
838         if (!buf)
839                 return -ENOMEM;
840 
841         if (copy_from_user(buf, ubuf, cnt)) {
842                 free_page((unsigned long) buf);
843                 return -EFAULT;
844         }
845         buf[cnt] = '\0';
846 
847         err = apply_event_filter(call, buf);
848         free_page((unsigned long) buf);
849         if (err < 0)
850                 return err;
851 
852         *ppos += cnt;
853 
854         return cnt;
855 }
856 
857 static LIST_HEAD(event_subsystems);
858 
859 static int subsystem_open(struct inode *inode, struct file *filp)
860 {
861         struct event_subsystem *system = NULL;
862         int ret;
863 
864         if (!inode->i_private)
865                 goto skip_search;
866 
867         /* Make sure the system still exists */
868         mutex_lock(&event_mutex);
869         list_for_each_entry(system, &event_subsystems, list) {
870                 if (system == inode->i_private) {
871                         /* Don't open systems with no events */
872                         if (!system->nr_events) {
873                                 system = NULL;
874                                 break;
875                         }
876                         __get_system(system);
877                         break;
878                 }
879         }
880         mutex_unlock(&event_mutex);
881 
882         if (system != inode->i_private)
883                 return -ENODEV;
884 
885  skip_search:
886         ret = tracing_open_generic(inode, filp);
887         if (ret < 0 && system)
888                 put_system(system);
889 
890         return ret;
891 }
892 
893 static int subsystem_release(struct inode *inode, struct file *file)
894 {
895         struct event_subsystem *system = inode->i_private;
896 
897         if (system)
898                 put_system(system);
899 
900         return 0;
901 }
902 
903 static ssize_t
904 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
905                       loff_t *ppos)
906 {
907         struct event_subsystem *system = filp->private_data;
908         struct trace_seq *s;
909         int r;
910 
911         if (*ppos)
912                 return 0;
913 
914         s = kmalloc(sizeof(*s), GFP_KERNEL);
915         if (!s)
916                 return -ENOMEM;
917 
918         trace_seq_init(s);
919 
920         print_subsystem_event_filter(system, s);
921         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
922 
923         kfree(s);
924 
925         return r;
926 }
927 
928 static ssize_t
929 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
930                        loff_t *ppos)
931 {
932         struct event_subsystem *system = filp->private_data;
933         char *buf;
934         int err;
935 
936         if (cnt >= PAGE_SIZE)
937                 return -EINVAL;
938 
939         buf = (char *)__get_free_page(GFP_TEMPORARY);
940         if (!buf)
941                 return -ENOMEM;
942 
943         if (copy_from_user(buf, ubuf, cnt)) {
944                 free_page((unsigned long) buf);
945                 return -EFAULT;
946         }
947         buf[cnt] = '\0';
948 
949         err = apply_subsystem_event_filter(system, buf);
950         free_page((unsigned long) buf);
951         if (err < 0)
952                 return err;
953 
954         *ppos += cnt;
955 
956         return cnt;
957 }
958 
959 static ssize_t
960 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
961 {
962         int (*func)(struct trace_seq *s) = filp->private_data;
963         struct trace_seq *s;
964         int r;
965 
966         if (*ppos)
967                 return 0;
968 
969         s = kmalloc(sizeof(*s), GFP_KERNEL);
970         if (!s)
971                 return -ENOMEM;
972 
973         trace_seq_init(s);
974 
975         func(s);
976         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
977 
978         kfree(s);
979 
980         return r;
981 }
982 
983 static const struct seq_operations show_event_seq_ops = {
984         .start = t_start,
985         .next = t_next,
986         .show = t_show,
987         .stop = t_stop,
988 };
989 
990 static const struct seq_operations show_set_event_seq_ops = {
991         .start = s_start,
992         .next = s_next,
993         .show = t_show,
994         .stop = t_stop,
995 };
996 
997 static const struct file_operations ftrace_avail_fops = {
998         .open = ftrace_event_seq_open,
999         .read = seq_read,
1000         .llseek = seq_lseek,
1001         .release = seq_release,
1002 };
1003 
1004 static const struct file_operations ftrace_set_event_fops = {
1005         .open = ftrace_event_seq_open,
1006         .read = seq_read,
1007         .write = ftrace_event_write,
1008         .llseek = seq_lseek,
1009         .release = seq_release,
1010 };
1011 
1012 static const struct file_operations ftrace_enable_fops = {
1013         .open = tracing_open_generic,
1014         .read = event_enable_read,
1015         .write = event_enable_write,
1016         .llseek = default_llseek,
1017 };
1018 
1019 static const struct file_operations ftrace_event_format_fops = {
1020         .open = trace_format_open,
1021         .read = seq_read,
1022         .llseek = seq_lseek,
1023         .release = seq_release,
1024 };
1025 
1026 static const struct file_operations ftrace_event_id_fops = {
1027         .open = tracing_open_generic,
1028         .read = event_id_read,
1029         .llseek = default_llseek,
1030 };
1031 
1032 static const struct file_operations ftrace_event_filter_fops = {
1033         .open = tracing_open_generic,
1034         .read = event_filter_read,
1035         .write = event_filter_write,
1036         .llseek = default_llseek,
1037 };
1038 
1039 static const struct file_operations ftrace_subsystem_filter_fops = {
1040         .open = subsystem_open,
1041         .read = subsystem_filter_read,
1042         .write = subsystem_filter_write,
1043         .llseek = default_llseek,
1044         .release = subsystem_release,
1045 };
1046 
1047 static const struct file_operations ftrace_system_enable_fops = {
1048         .open = subsystem_open,
1049         .read = system_enable_read,
1050         .write = system_enable_write,
1051         .llseek = default_llseek,
1052         .release = subsystem_release,
1053 };
1054 
1055 static const struct file_operations ftrace_show_header_fops = {
1056         .open = tracing_open_generic,
1057         .read = show_header,
1058         .llseek = default_llseek,
1059 };
1060 
1061 static struct dentry *event_trace_events_dir(void)
1062 {
1063         static struct dentry *d_tracer;
1064         static struct dentry *d_events;
1065 
1066         if (d_events)
1067                 return d_events;
1068 
1069         d_tracer = tracing_init_dentry();
1070         if (!d_tracer)
1071                 return NULL;
1072 
1073         d_events = debugfs_create_dir("events", d_tracer);
1074         if (!d_events)
1075                 pr_warning("Could not create debugfs "
1076                            "'events' directory\n");
1077 
1078         return d_events;
1079 }
1080 
1081 static struct dentry *
1082 event_subsystem_dir(const char *name, struct dentry *d_events)
1083 {
1084         struct event_subsystem *system;
1085         struct dentry *entry;
1086 
1087         /* First see if we did not already create this dir */
1088         list_for_each_entry(system, &event_subsystems, list) {
1089                 if (strcmp(system->name, name) == 0) {
1090                         system->nr_events++;
1091                         return system->entry;
1092                 }
1093         }
1094 
1095         /* need to create new entry */
1096         system = kmalloc(sizeof(*system), GFP_KERNEL);
1097         if (!system) {
1098                 pr_warning("No memory to create event subsystem %s\n",
1099                            name);
1100                 return d_events;
1101         }
1102 
1103         system->entry = debugfs_create_dir(name, d_events);
1104         if (!system->entry) {
1105                 pr_warning("Could not create event subsystem %s\n",
1106                            name);
1107                 kfree(system);
1108                 return d_events;
1109         }
1110 
1111         system->nr_events = 1;
1112         system->ref_count = 1;
1113         system->name = kstrdup(name, GFP_KERNEL);
1114         if (!system->name) {
1115                 debugfs_remove(system->entry);
1116                 kfree(system);
1117                 return d_events;
1118         }
1119 
1120         list_add(&system->list, &event_subsystems);
1121 
1122         system->filter = NULL;
1123 
1124         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1125         if (!system->filter) {
1126                 pr_warning("Could not allocate filter for subsystem "
1127                            "'%s'\n", name);
1128                 return system->entry;
1129         }
1130 
1131         entry = debugfs_create_file("filter", 0644, system->entry, system,
1132                                     &ftrace_subsystem_filter_fops);
1133         if (!entry) {
1134                 kfree(system->filter);
1135                 system->filter = NULL;
1136                 pr_warning("Could not create debugfs "
1137                            "'%s/filter' entry\n", name);
1138         }
1139 
1140         trace_create_file("enable", 0644, system->entry, system,
1141                           &ftrace_system_enable_fops);
1142 
1143         return system->entry;
1144 }
1145 
1146 static int
1147 event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
1148                  const struct file_operations *id,
1149                  const struct file_operations *enable,
1150                  const struct file_operations *filter,
1151                  const struct file_operations *format)
1152 {
1153         struct list_head *head;
1154         int ret;
1155 
1156         /*
1157          * If the trace point header did not define TRACE_SYSTEM
1158          * then the system would be called "TRACE_SYSTEM".
1159          */
1160         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1161                 d_events = event_subsystem_dir(call->class->system, d_events);
1162 
1163         call->dir = debugfs_create_dir(call->name, d_events);
1164         if (!call->dir) {
1165                 pr_warning("Could not create debugfs "
1166                            "'%s' directory\n", call->name);
1167                 return -1;
1168         }
1169 
1170         if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1171                 trace_create_file("enable", 0644, call->dir, call,
1172                                   enable);
1173 
1174 #ifdef CONFIG_PERF_EVENTS
1175         if (call->event.type && call->class->reg)
1176                 trace_create_file("id", 0444, call->dir, call,
1177                                   id);
1178 #endif
1179 
1180         /*
1181          * Other events may have the same class. Only update
1182          * the fields if they are not already defined.
1183          */
1184         head = trace_get_fields(call);
1185         if (list_empty(head)) {
1186                 ret = call->class->define_fields(call);
1187                 if (ret < 0) {
1188                         pr_warning("Could not initialize trace point"
1189                                    " events/%s\n", call->name);
1190                         return ret;
1191                 }
1192         }
1193         trace_create_file("filter", 0644, call->dir, call,
1194                           filter);
1195 
1196         trace_create_file("format", 0444, call->dir, call,
1197                           format);
1198 
1199         return 0;
1200 }
1201 
1202 static int
1203 __trace_add_event_call(struct ftrace_event_call *call, struct module *mod,
1204                        const struct file_operations *id,
1205                        const struct file_operations *enable,
1206                        const struct file_operations *filter,
1207                        const struct file_operations *format)
1208 {
1209         struct dentry *d_events;
1210         int ret;
1211 
1212         /* The linker may leave blanks */
1213         if (!call->name)
1214                 return -EINVAL;
1215 
1216         if (call->class->raw_init) {
1217                 ret = call->class->raw_init(call);
1218                 if (ret < 0) {
1219                         if (ret != -ENOSYS)
1220                                 pr_warning("Could not initialize trace events/%s\n",
1221                                            call->name);
1222                         return ret;
1223                 }
1224         }
1225 
1226         d_events = event_trace_events_dir();
1227         if (!d_events)
1228                 return -ENOENT;
1229 
1230         ret = event_create_dir(call, d_events, id, enable, filter, format);
1231         if (!ret)
1232                 list_add(&call->list, &ftrace_events);
1233         call->mod = mod;
1234 
1235         return ret;
1236 }
1237 
1238 /* Add an additional event_call dynamically */
1239 int trace_add_event_call(struct ftrace_event_call *call)
1240 {
1241         int ret;
1242         mutex_lock(&event_mutex);
1243         ret = __trace_add_event_call(call, NULL, &ftrace_event_id_fops,
1244                                      &ftrace_enable_fops,
1245                                      &ftrace_event_filter_fops,
1246                                      &ftrace_event_format_fops);
1247         mutex_unlock(&event_mutex);
1248         return ret;
1249 }
1250 
1251 static void remove_subsystem_dir(const char *name)
1252 {
1253         struct event_subsystem *system;
1254 
1255         if (strcmp(name, TRACE_SYSTEM) == 0)
1256                 return;
1257 
1258         list_for_each_entry(system, &event_subsystems, list) {
1259                 if (strcmp(system->name, name) == 0) {
1260                         if (!--system->nr_events) {
1261                                 debugfs_remove_recursive(system->entry);
1262                                 list_del(&system->list);
1263                                 __put_system(system);
1264                         }
1265                         break;
1266                 }
1267         }
1268 }
1269 
1270 /*
1271  * Must be called under locking both of event_mutex and trace_event_mutex.
1272  */
1273 static void __trace_remove_event_call(struct ftrace_event_call *call)
1274 {
1275         ftrace_event_enable_disable(call, 0);
1276         if (call->event.funcs)
1277                 __unregister_ftrace_event(&call->event);
1278         debugfs_remove_recursive(call->dir);
1279         list_del(&call->list);
1280         trace_destroy_fields(call);
1281         destroy_preds(call);
1282         remove_subsystem_dir(call->class->system);
1283 }
1284 
1285 /* Remove an event_call */
1286 void trace_remove_event_call(struct ftrace_event_call *call)
1287 {
1288         mutex_lock(&event_mutex);
1289         down_write(&trace_event_mutex);
1290         __trace_remove_event_call(call);
1291         up_write(&trace_event_mutex);
1292         mutex_unlock(&event_mutex);
1293 }
1294 
1295 #define for_each_event(event, start, end)                       \
1296         for (event = start;                                     \
1297              (unsigned long)event < (unsigned long)end;         \
1298              event++)
1299 
1300 #ifdef CONFIG_MODULES
1301 
1302 static LIST_HEAD(ftrace_module_file_list);
1303 
1304 /*
1305  * Modules must own their file_operations to keep up with
1306  * reference counting.
1307  */
1308 struct ftrace_module_file_ops {
1309         struct list_head                list;
1310         struct module                   *mod;
1311         struct file_operations          id;
1312         struct file_operations          enable;
1313         struct file_operations          format;
1314         struct file_operations          filter;
1315 };
1316 
1317 static struct ftrace_module_file_ops *
1318 trace_create_file_ops(struct module *mod)
1319 {
1320         struct ftrace_module_file_ops *file_ops;
1321 
1322         /*
1323          * This is a bit of a PITA. To allow for correct reference
1324          * counting, modules must "own" their file_operations.
1325          * To do this, we allocate the file operations that will be
1326          * used in the event directory.
1327          */
1328 
1329         file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1330         if (!file_ops)
1331                 return NULL;
1332 
1333         file_ops->mod = mod;
1334 
1335         file_ops->id = ftrace_event_id_fops;
1336         file_ops->id.owner = mod;
1337 
1338         file_ops->enable = ftrace_enable_fops;
1339         file_ops->enable.owner = mod;
1340 
1341         file_ops->filter = ftrace_event_filter_fops;
1342         file_ops->filter.owner = mod;
1343 
1344         file_ops->format = ftrace_event_format_fops;
1345         file_ops->format.owner = mod;
1346 
1347         list_add(&file_ops->list, &ftrace_module_file_list);
1348 
1349         return file_ops;
1350 }
1351 
1352 static void trace_module_add_events(struct module *mod)
1353 {
1354         struct ftrace_module_file_ops *file_ops = NULL;
1355         struct ftrace_event_call **call, **start, **end;
1356 
1357         if (!mod->num_trace_events)
1358                 return;
1359 
1360         /* Don't add infrastructure for mods without tracepoints */
1361         if (trace_module_has_bad_taint(mod)) {
1362                 pr_err("%s: module has bad taint, not creating trace events\n",
1363                        mod->name);
1364                 return;
1365         }
1366 
1367         start = mod->trace_events;
1368         end = mod->trace_events + mod->num_trace_events;
1369 
1370         if (start == end)
1371                 return;
1372 
1373         file_ops = trace_create_file_ops(mod);
1374         if (!file_ops)
1375                 return;
1376 
1377         for_each_event(call, start, end) {
1378                 __trace_add_event_call(*call, mod,
1379                                        &file_ops->id, &file_ops->enable,
1380                                        &file_ops->filter, &file_ops->format);
1381         }
1382 }
1383 
1384 static void trace_module_remove_events(struct module *mod)
1385 {
1386         struct ftrace_module_file_ops *file_ops;
1387         struct ftrace_event_call *call, *p;
1388         bool found = false;
1389 
1390         down_write(&trace_event_mutex);
1391         list_for_each_entry_safe(call, p, &ftrace_events, list) {
1392                 if (call->mod == mod) {
1393                         found = true;
1394                         __trace_remove_event_call(call);
1395                 }
1396         }
1397 
1398         /* Now free the file_operations */
1399         list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1400                 if (file_ops->mod == mod)
1401                         break;
1402         }
1403         if (&file_ops->list != &ftrace_module_file_list) {
1404                 list_del(&file_ops->list);
1405                 kfree(file_ops);
1406         }
1407 
1408         /*
1409          * It is safest to reset the ring buffer if the module being unloaded
1410          * registered any events.
1411          */
1412         if (found)
1413                 tracing_reset_current_online_cpus();
1414         up_write(&trace_event_mutex);
1415 }
1416 
1417 static int trace_module_notify(struct notifier_block *self,
1418                                unsigned long val, void *data)
1419 {
1420         struct module *mod = data;
1421 
1422         mutex_lock(&event_mutex);
1423         switch (val) {
1424         case MODULE_STATE_COMING:
1425                 trace_module_add_events(mod);
1426                 break;
1427         case MODULE_STATE_GOING:
1428                 trace_module_remove_events(mod);
1429                 break;
1430         }
1431         mutex_unlock(&event_mutex);
1432 
1433         return 0;
1434 }
1435 #else
1436 static int trace_module_notify(struct notifier_block *self,
1437                                unsigned long val, void *data)
1438 {
1439         return 0;
1440 }
1441 #endif /* CONFIG_MODULES */
1442 
1443 static struct notifier_block trace_module_nb = {
1444         .notifier_call = trace_module_notify,
1445         .priority = 0,
1446 };
1447 
1448 extern struct ftrace_event_call *__start_ftrace_events[];
1449 extern struct ftrace_event_call *__stop_ftrace_events[];
1450 
1451 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
1452 
1453 static __init int setup_trace_event(char *str)
1454 {
1455         strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
1456         ring_buffer_expanded = 1;
1457         tracing_selftest_disabled = 1;
1458 
1459         return 1;
1460 }
1461 __setup("trace_event=", setup_trace_event);
1462 
1463 static __init int event_trace_init(void)
1464 {
1465         struct ftrace_event_call **call;
1466         struct dentry *d_tracer;
1467         struct dentry *entry;
1468         struct dentry *d_events;
1469         int ret;
1470         char *buf = bootup_event_buf;
1471         char *token;
1472 
1473         d_tracer = tracing_init_dentry();
1474         if (!d_tracer)
1475                 return 0;
1476 
1477         entry = debugfs_create_file("available_events", 0444, d_tracer,
1478                                     (void *)&show_event_seq_ops,
1479                                     &ftrace_avail_fops);
1480         if (!entry)
1481                 pr_warning("Could not create debugfs "
1482                            "'available_events' entry\n");
1483 
1484         entry = debugfs_create_file("set_event", 0644, d_tracer,
1485                                     (void *)&show_set_event_seq_ops,
1486                                     &ftrace_set_event_fops);
1487         if (!entry)
1488                 pr_warning("Could not create debugfs "
1489                            "'set_event' entry\n");
1490 
1491         d_events = event_trace_events_dir();
1492         if (!d_events)
1493                 return 0;
1494 
1495         /* ring buffer internal formats */
1496         trace_create_file("header_page", 0444, d_events,
1497                           ring_buffer_print_page_header,
1498                           &ftrace_show_header_fops);
1499 
1500         trace_create_file("header_event", 0444, d_events,
1501                           ring_buffer_print_entry_header,
1502                           &ftrace_show_header_fops);
1503 
1504         trace_create_file("enable", 0644, d_events,
1505                           NULL, &ftrace_system_enable_fops);
1506 
1507         if (trace_define_common_fields())
1508                 pr_warning("tracing: Failed to allocate common fields");
1509 
1510         for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
1511                 __trace_add_event_call(*call, NULL, &ftrace_event_id_fops,
1512                                        &ftrace_enable_fops,
1513                                        &ftrace_event_filter_fops,
1514                                        &ftrace_event_format_fops);
1515         }
1516 
1517         while (true) {
1518                 token = strsep(&buf, ",");
1519 
1520                 if (!token)
1521                         break;
1522                 if (!*token)
1523                         continue;
1524 
1525                 ret = ftrace_set_clr_event(token, 1);
1526                 if (ret)
1527                         pr_warning("Failed to enable trace event: %s\n", token);
1528         }
1529 
1530         ret = register_module_notifier(&trace_module_nb);
1531         if (ret)
1532                 pr_warning("Failed to register trace events module notifier\n");
1533 
1534         return 0;
1535 }
1536 fs_initcall(event_trace_init);
1537 
1538 #ifdef CONFIG_FTRACE_STARTUP_TEST
1539 
1540 static DEFINE_SPINLOCK(test_spinlock);
1541 static DEFINE_SPINLOCK(test_spinlock_irq);
1542 static DEFINE_MUTEX(test_mutex);
1543 
1544 static __init void test_work(struct work_struct *dummy)
1545 {
1546         spin_lock(&test_spinlock);
1547         spin_lock_irq(&test_spinlock_irq);
1548         udelay(1);
1549         spin_unlock_irq(&test_spinlock_irq);
1550         spin_unlock(&test_spinlock);
1551 
1552         mutex_lock(&test_mutex);
1553         msleep(1);
1554         mutex_unlock(&test_mutex);
1555 }
1556 
1557 static __init int event_test_thread(void *unused)
1558 {
1559         void *test_malloc;
1560 
1561         test_malloc = kmalloc(1234, GFP_KERNEL);
1562         if (!test_malloc)
1563                 pr_info("failed to kmalloc\n");
1564 
1565         schedule_on_each_cpu(test_work);
1566 
1567         kfree(test_malloc);
1568 
1569         set_current_state(TASK_INTERRUPTIBLE);
1570         while (!kthread_should_stop())
1571                 schedule();
1572 
1573         return 0;
1574 }
1575 
1576 /*
1577  * Do various things that may trigger events.
1578  */
1579 static __init void event_test_stuff(void)
1580 {
1581         struct task_struct *test_thread;
1582 
1583         test_thread = kthread_run(event_test_thread, NULL, "test-events");
1584         msleep(1);
1585         kthread_stop(test_thread);
1586 }
1587 
1588 /*
1589  * For every trace event defined, we will test each trace point separately,
1590  * and then by groups, and finally all trace points.
1591  */
1592 static __init void event_trace_self_tests(void)
1593 {
1594         struct ftrace_event_call *call;
1595         struct event_subsystem *system;
1596         int ret;
1597 
1598         pr_info("Running tests on trace events:\n");
1599 
1600         list_for_each_entry(call, &ftrace_events, list) {
1601 
1602                 /* Only test those that have a probe */
1603                 if (!call->class || !call->class->probe)
1604                         continue;
1605 
1606 /*
1607  * Testing syscall events here is pretty useless, but
1608  * we still do it if configured. But this is time consuming.
1609  * What we really need is a user thread to perform the
1610  * syscalls as we test.
1611  */
1612 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
1613                 if (call->class->system &&
1614                     strcmp(call->class->system, "syscalls") == 0)
1615                         continue;
1616 #endif
1617 
1618                 pr_info("Testing event %s: ", call->name);
1619 
1620                 /*
1621                  * If an event is already enabled, someone is using
1622                  * it and the self test should not be on.
1623                  */
1624                 if (call->flags & TRACE_EVENT_FL_ENABLED) {
1625                         pr_warning("Enabled event during self test!\n");
1626                         WARN_ON_ONCE(1);
1627                         continue;
1628                 }
1629 
1630                 ftrace_event_enable_disable(call, 1);
1631                 event_test_stuff();
1632                 ftrace_event_enable_disable(call, 0);
1633 
1634                 pr_cont("OK\n");
1635         }
1636 
1637         /* Now test at the sub system level */
1638 
1639         pr_info("Running tests on trace event systems:\n");
1640 
1641         list_for_each_entry(system, &event_subsystems, list) {
1642 
1643                 /* the ftrace system is special, skip it */
1644                 if (strcmp(system->name, "ftrace") == 0)
1645                         continue;
1646 
1647                 pr_info("Testing event system %s: ", system->name);
1648 
1649                 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
1650                 if (WARN_ON_ONCE(ret)) {
1651                         pr_warning("error enabling system %s\n",
1652                                    system->name);
1653                         continue;
1654                 }
1655 
1656                 event_test_stuff();
1657 
1658                 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
1659                 if (WARN_ON_ONCE(ret))
1660                         pr_warning("error disabling system %s\n",
1661                                    system->name);
1662 
1663                 pr_cont("OK\n");
1664         }
1665 
1666         /* Test with all events enabled */
1667 
1668         pr_info("Running tests on all trace events:\n");
1669         pr_info("Testing all events: ");
1670 
1671         ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
1672         if (WARN_ON_ONCE(ret)) {
1673                 pr_warning("error enabling all events\n");
1674                 return;
1675         }
1676 
1677         event_test_stuff();
1678 
1679         /* reset sysname */
1680         ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
1681         if (WARN_ON_ONCE(ret)) {
1682                 pr_warning("error disabling all events\n");
1683                 return;
1684         }
1685 
1686         pr_cont("OK\n");
1687 }
1688 
1689 #ifdef CONFIG_FUNCTION_TRACER
1690 
1691 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
1692 
1693 static void
1694 function_test_events_call(unsigned long ip, unsigned long parent_ip)
1695 {
1696         struct ring_buffer_event *event;
1697         struct ring_buffer *buffer;
1698         struct ftrace_entry *entry;
1699         unsigned long flags;
1700         long disabled;
1701         int cpu;
1702         int pc;
1703 
1704         pc = preempt_count();
1705         preempt_disable_notrace();
1706         cpu = raw_smp_processor_id();
1707         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
1708 
1709         if (disabled != 1)
1710                 goto out;
1711 
1712         local_save_flags(flags);
1713 
1714         event = trace_current_buffer_lock_reserve(&buffer,
1715                                                   TRACE_FN, sizeof(*entry),
1716                                                   flags, pc);
1717         if (!event)
1718                 goto out;
1719         entry   = ring_buffer_event_data(event);
1720         entry->ip                       = ip;
1721         entry->parent_ip                = parent_ip;
1722 
1723         trace_nowake_buffer_unlock_commit(buffer, event, flags, pc);
1724 
1725  out:
1726         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
1727         preempt_enable_notrace();
1728 }
1729 
1730 static struct ftrace_ops trace_ops __initdata  =
1731 {
1732         .func = function_test_events_call,
1733 };
1734 
1735 static __init void event_trace_self_test_with_function(void)
1736 {
1737         int ret;
1738         ret = register_ftrace_function(&trace_ops);
1739         if (WARN_ON(ret < 0)) {
1740                 pr_info("Failed to enable function tracer for event tests\n");
1741                 return;
1742         }
1743         pr_info("Running tests again, along with the function tracer\n");
1744         event_trace_self_tests();
1745         unregister_ftrace_function(&trace_ops);
1746 }
1747 #else
1748 static __init void event_trace_self_test_with_function(void)
1749 {
1750 }
1751 #endif
1752 
1753 static __init int event_trace_self_tests_init(void)
1754 {
1755         if (!tracing_selftest_disabled) {
1756                 event_trace_self_tests();
1757                 event_trace_self_test_with_function();
1758         }
1759 
1760         return 0;
1761 }
1762 
1763 late_initcall(event_trace_self_tests_init);
1764 
1765 #endif
1766 

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