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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 static LIST_HEAD(ftrace_common_fields);
 38 
 39 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
 40 
 41 static struct kmem_cache *field_cachep;
 42 static struct kmem_cache *file_cachep;
 43 
 44 #define SYSTEM_FL_FREE_NAME             (1 << 31)
 45 
 46 static inline int system_refcount(struct event_subsystem *system)
 47 {
 48         return system->ref_count & ~SYSTEM_FL_FREE_NAME;
 49 }
 50 
 51 static int system_refcount_inc(struct event_subsystem *system)
 52 {
 53         return (system->ref_count++) & ~SYSTEM_FL_FREE_NAME;
 54 }
 55 
 56 static int system_refcount_dec(struct event_subsystem *system)
 57 {
 58         return (--system->ref_count) & ~SYSTEM_FL_FREE_NAME;
 59 }
 60 
 61 /* Double loops, do not use break, only goto's work */
 62 #define do_for_each_event_file(tr, file)                        \
 63         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
 64                 list_for_each_entry(file, &tr->events, list)
 65 
 66 #define do_for_each_event_file_safe(tr, file)                   \
 67         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
 68                 struct ftrace_event_file *___n;                         \
 69                 list_for_each_entry_safe(file, ___n, &tr->events, list)
 70 
 71 #define while_for_each_event_file()             \
 72         }
 73 
 74 static struct list_head *
 75 trace_get_fields(struct ftrace_event_call *event_call)
 76 {
 77         if (!event_call->class->get_fields)
 78                 return &event_call->class->fields;
 79         return event_call->class->get_fields(event_call);
 80 }
 81 
 82 static struct ftrace_event_field *
 83 __find_event_field(struct list_head *head, char *name)
 84 {
 85         struct ftrace_event_field *field;
 86 
 87         list_for_each_entry(field, head, link) {
 88                 if (!strcmp(field->name, name))
 89                         return field;
 90         }
 91 
 92         return NULL;
 93 }
 94 
 95 struct ftrace_event_field *
 96 trace_find_event_field(struct ftrace_event_call *call, char *name)
 97 {
 98         struct ftrace_event_field *field;
 99         struct list_head *head;
100 
101         field = __find_event_field(&ftrace_common_fields, name);
102         if (field)
103                 return field;
104 
105         head = trace_get_fields(call);
106         return __find_event_field(head, name);
107 }
108 
109 static int __trace_define_field(struct list_head *head, const char *type,
110                                 const char *name, int offset, int size,
111                                 int is_signed, int filter_type)
112 {
113         struct ftrace_event_field *field;
114 
115         field = kmem_cache_alloc(field_cachep, GFP_TRACE);
116         if (!field)
117                 return -ENOMEM;
118 
119         field->name = name;
120         field->type = type;
121 
122         if (filter_type == FILTER_OTHER)
123                 field->filter_type = filter_assign_type(type);
124         else
125                 field->filter_type = filter_type;
126 
127         field->offset = offset;
128         field->size = size;
129         field->is_signed = is_signed;
130 
131         list_add(&field->link, head);
132 
133         return 0;
134 }
135 
136 int trace_define_field(struct ftrace_event_call *call, const char *type,
137                        const char *name, int offset, int size, int is_signed,
138                        int filter_type)
139 {
140         struct list_head *head;
141 
142         if (WARN_ON(!call->class))
143                 return 0;
144 
145         head = trace_get_fields(call);
146         return __trace_define_field(head, type, name, offset, size,
147                                     is_signed, filter_type);
148 }
149 EXPORT_SYMBOL_GPL(trace_define_field);
150 
151 #define __common_field(type, item)                                      \
152         ret = __trace_define_field(&ftrace_common_fields, #type,        \
153                                    "common_" #item,                     \
154                                    offsetof(typeof(ent), item),         \
155                                    sizeof(ent.item),                    \
156                                    is_signed_type(type), FILTER_OTHER); \
157         if (ret)                                                        \
158                 return ret;
159 
160 static int trace_define_common_fields(void)
161 {
162         int ret;
163         struct trace_entry ent;
164 
165         __common_field(unsigned short, type);
166         __common_field(unsigned char, flags);
167         __common_field(unsigned char, preempt_count);
168         __common_field(int, pid);
169 
170         return ret;
171 }
172 
173 static void trace_destroy_fields(struct ftrace_event_call *call)
174 {
175         struct ftrace_event_field *field, *next;
176         struct list_head *head;
177 
178         head = trace_get_fields(call);
179         list_for_each_entry_safe(field, next, head, link) {
180                 list_del(&field->link);
181                 kmem_cache_free(field_cachep, field);
182         }
183 }
184 
185 int trace_event_raw_init(struct ftrace_event_call *call)
186 {
187         int id;
188 
189         id = register_ftrace_event(&call->event);
190         if (!id)
191                 return -ENODEV;
192 
193         return 0;
194 }
195 EXPORT_SYMBOL_GPL(trace_event_raw_init);
196 
197 int ftrace_event_reg(struct ftrace_event_call *call,
198                      enum trace_reg type, void *data)
199 {
200         struct ftrace_event_file *file = data;
201 
202         switch (type) {
203         case TRACE_REG_REGISTER:
204                 return tracepoint_probe_register(call->name,
205                                                  call->class->probe,
206                                                  file);
207         case TRACE_REG_UNREGISTER:
208                 tracepoint_probe_unregister(call->name,
209                                             call->class->probe,
210                                             file);
211                 return 0;
212 
213 #ifdef CONFIG_PERF_EVENTS
214         case TRACE_REG_PERF_REGISTER:
215                 return tracepoint_probe_register(call->name,
216                                                  call->class->perf_probe,
217                                                  call);
218         case TRACE_REG_PERF_UNREGISTER:
219                 tracepoint_probe_unregister(call->name,
220                                             call->class->perf_probe,
221                                             call);
222                 return 0;
223         case TRACE_REG_PERF_OPEN:
224         case TRACE_REG_PERF_CLOSE:
225         case TRACE_REG_PERF_ADD:
226         case TRACE_REG_PERF_DEL:
227                 return 0;
228 #endif
229         }
230         return 0;
231 }
232 EXPORT_SYMBOL_GPL(ftrace_event_reg);
233 
234 void trace_event_enable_cmd_record(bool enable)
235 {
236         struct ftrace_event_file *file;
237         struct trace_array *tr;
238 
239         mutex_lock(&event_mutex);
240         do_for_each_event_file(tr, file) {
241 
242                 if (!(file->flags & FTRACE_EVENT_FL_ENABLED))
243                         continue;
244 
245                 if (enable) {
246                         tracing_start_cmdline_record();
247                         set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
248                 } else {
249                         tracing_stop_cmdline_record();
250                         clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
251                 }
252         } while_for_each_event_file();
253         mutex_unlock(&event_mutex);
254 }
255 
256 static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
257                                          int enable, int soft_disable)
258 {
259         struct ftrace_event_call *call = file->event_call;
260         int ret = 0;
261         int disable;
262 
263         switch (enable) {
264         case 0:
265                 /*
266                  * When soft_disable is set and enable is cleared, the sm_ref
267                  * reference counter is decremented. If it reaches 0, we want
268                  * to clear the SOFT_DISABLED flag but leave the event in the
269                  * state that it was. That is, if the event was enabled and
270                  * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
271                  * is set we do not want the event to be enabled before we
272                  * clear the bit.
273                  *
274                  * When soft_disable is not set but the SOFT_MODE flag is,
275                  * we do nothing. Do not disable the tracepoint, otherwise
276                  * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
277                  */
278                 if (soft_disable) {
279                         if (atomic_dec_return(&file->sm_ref) > 0)
280                                 break;
281                         disable = file->flags & FTRACE_EVENT_FL_SOFT_DISABLED;
282                         clear_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
283                 } else
284                         disable = !(file->flags & FTRACE_EVENT_FL_SOFT_MODE);
285 
286                 if (disable && (file->flags & FTRACE_EVENT_FL_ENABLED)) {
287                         clear_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
288                         if (file->flags & FTRACE_EVENT_FL_RECORDED_CMD) {
289                                 tracing_stop_cmdline_record();
290                                 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
291                         }
292                         call->class->reg(call, TRACE_REG_UNREGISTER, file);
293                 }
294                 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
295                 if (file->flags & FTRACE_EVENT_FL_SOFT_MODE)
296                         set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
297                 else
298                         clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
299                 break;
300         case 1:
301                 /*
302                  * When soft_disable is set and enable is set, we want to
303                  * register the tracepoint for the event, but leave the event
304                  * as is. That means, if the event was already enabled, we do
305                  * nothing (but set SOFT_MODE). If the event is disabled, we
306                  * set SOFT_DISABLED before enabling the event tracepoint, so
307                  * it still seems to be disabled.
308                  */
309                 if (!soft_disable)
310                         clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
311                 else {
312                         if (atomic_inc_return(&file->sm_ref) > 1)
313                                 break;
314                         set_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
315                 }
316 
317                 if (!(file->flags & FTRACE_EVENT_FL_ENABLED)) {
318 
319                         /* Keep the event disabled, when going to SOFT_MODE. */
320                         if (soft_disable)
321                                 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
322 
323                         if (trace_flags & TRACE_ITER_RECORD_CMD) {
324                                 tracing_start_cmdline_record();
325                                 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags);
326                         }
327                         ret = call->class->reg(call, TRACE_REG_REGISTER, file);
328                         if (ret) {
329                                 tracing_stop_cmdline_record();
330                                 pr_info("event trace: Could not enable event "
331                                         "%s\n", call->name);
332                                 break;
333                         }
334                         set_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags);
335 
336                         /* WAS_ENABLED gets set but never cleared. */
337                         call->flags |= TRACE_EVENT_FL_WAS_ENABLED;
338                 }
339                 break;
340         }
341 
342         return ret;
343 }
344 
345 static int ftrace_event_enable_disable(struct ftrace_event_file *file,
346                                        int enable)
347 {
348         return __ftrace_event_enable_disable(file, enable, 0);
349 }
350 
351 static void ftrace_clear_events(struct trace_array *tr)
352 {
353         struct ftrace_event_file *file;
354 
355         mutex_lock(&event_mutex);
356         list_for_each_entry(file, &tr->events, list) {
357                 ftrace_event_enable_disable(file, 0);
358         }
359         mutex_unlock(&event_mutex);
360 }
361 
362 static void __put_system(struct event_subsystem *system)
363 {
364         struct event_filter *filter = system->filter;
365 
366         WARN_ON_ONCE(system_refcount(system) == 0);
367         if (system_refcount_dec(system))
368                 return;
369 
370         list_del(&system->list);
371 
372         if (filter) {
373                 kfree(filter->filter_string);
374                 kfree(filter);
375         }
376         if (system->ref_count & SYSTEM_FL_FREE_NAME)
377                 kfree(system->name);
378         kfree(system);
379 }
380 
381 static void __get_system(struct event_subsystem *system)
382 {
383         WARN_ON_ONCE(system_refcount(system) == 0);
384         system_refcount_inc(system);
385 }
386 
387 static void __get_system_dir(struct ftrace_subsystem_dir *dir)
388 {
389         WARN_ON_ONCE(dir->ref_count == 0);
390         dir->ref_count++;
391         __get_system(dir->subsystem);
392 }
393 
394 static void __put_system_dir(struct ftrace_subsystem_dir *dir)
395 {
396         WARN_ON_ONCE(dir->ref_count == 0);
397         /* If the subsystem is about to be freed, the dir must be too */
398         WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
399 
400         __put_system(dir->subsystem);
401         if (!--dir->ref_count)
402                 kfree(dir);
403 }
404 
405 static void put_system(struct ftrace_subsystem_dir *dir)
406 {
407         mutex_lock(&event_mutex);
408         __put_system_dir(dir);
409         mutex_unlock(&event_mutex);
410 }
411 
412 static void remove_subsystem(struct ftrace_subsystem_dir *dir)
413 {
414         if (!dir)
415                 return;
416 
417         if (!--dir->nr_events) {
418                 debugfs_remove_recursive(dir->entry);
419                 list_del(&dir->list);
420                 __put_system_dir(dir);
421         }
422 }
423 
424 static void *event_file_data(struct file *filp)
425 {
426         return ACCESS_ONCE(file_inode(filp)->i_private);
427 }
428 
429 static void remove_event_file_dir(struct ftrace_event_file *file)
430 {
431         struct dentry *dir = file->dir;
432         struct dentry *child;
433 
434         if (dir) {
435                 spin_lock(&dir->d_lock);        /* probably unneeded */
436                 list_for_each_entry(child, &dir->d_subdirs, d_u.d_child) {
437                         if (child->d_inode)     /* probably unneeded */
438                                 child->d_inode->i_private = NULL;
439                 }
440                 spin_unlock(&dir->d_lock);
441 
442                 debugfs_remove_recursive(dir);
443         }
444 
445         list_del(&file->list);
446         remove_subsystem(file->system);
447         kmem_cache_free(file_cachep, file);
448 }
449 
450 /*
451  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
452  */
453 static int
454 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
455                               const char *sub, const char *event, int set)
456 {
457         struct ftrace_event_file *file;
458         struct ftrace_event_call *call;
459         int ret = -EINVAL;
460 
461         list_for_each_entry(file, &tr->events, list) {
462 
463                 call = file->event_call;
464 
465                 if (!call->name || !call->class || !call->class->reg)
466                         continue;
467 
468                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
469                         continue;
470 
471                 if (match &&
472                     strcmp(match, call->name) != 0 &&
473                     strcmp(match, call->class->system) != 0)
474                         continue;
475 
476                 if (sub && strcmp(sub, call->class->system) != 0)
477                         continue;
478 
479                 if (event && strcmp(event, call->name) != 0)
480                         continue;
481 
482                 ftrace_event_enable_disable(file, set);
483 
484                 ret = 0;
485         }
486 
487         return ret;
488 }
489 
490 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
491                                   const char *sub, const char *event, int set)
492 {
493         int ret;
494 
495         mutex_lock(&event_mutex);
496         ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
497         mutex_unlock(&event_mutex);
498 
499         return ret;
500 }
501 
502 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
503 {
504         char *event = NULL, *sub = NULL, *match;
505 
506         /*
507          * The buf format can be <subsystem>:<event-name>
508          *  *:<event-name> means any event by that name.
509          *  :<event-name> is the same.
510          *
511          *  <subsystem>:* means all events in that subsystem
512          *  <subsystem>: means the same.
513          *
514          *  <name> (no ':') means all events in a subsystem with
515          *  the name <name> or any event that matches <name>
516          */
517 
518         match = strsep(&buf, ":");
519         if (buf) {
520                 sub = match;
521                 event = buf;
522                 match = NULL;
523 
524                 if (!strlen(sub) || strcmp(sub, "*") == 0)
525                         sub = NULL;
526                 if (!strlen(event) || strcmp(event, "*") == 0)
527                         event = NULL;
528         }
529 
530         return __ftrace_set_clr_event(tr, match, sub, event, set);
531 }
532 
533 /**
534  * trace_set_clr_event - enable or disable an event
535  * @system: system name to match (NULL for any system)
536  * @event: event name to match (NULL for all events, within system)
537  * @set: 1 to enable, 0 to disable
538  *
539  * This is a way for other parts of the kernel to enable or disable
540  * event recording.
541  *
542  * Returns 0 on success, -EINVAL if the parameters do not match any
543  * registered events.
544  */
545 int trace_set_clr_event(const char *system, const char *event, int set)
546 {
547         struct trace_array *tr = top_trace_array();
548 
549         return __ftrace_set_clr_event(tr, NULL, system, event, set);
550 }
551 EXPORT_SYMBOL_GPL(trace_set_clr_event);
552 
553 /* 128 should be much more than enough */
554 #define EVENT_BUF_SIZE          127
555 
556 static ssize_t
557 ftrace_event_write(struct file *file, const char __user *ubuf,
558                    size_t cnt, loff_t *ppos)
559 {
560         struct trace_parser parser;
561         struct seq_file *m = file->private_data;
562         struct trace_array *tr = m->private;
563         ssize_t read, ret;
564 
565         if (!cnt)
566                 return 0;
567 
568         ret = tracing_update_buffers();
569         if (ret < 0)
570                 return ret;
571 
572         if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
573                 return -ENOMEM;
574 
575         read = trace_get_user(&parser, ubuf, cnt, ppos);
576 
577         if (read >= 0 && trace_parser_loaded((&parser))) {
578                 int set = 1;
579 
580                 if (*parser.buffer == '!')
581                         set = 0;
582 
583                 parser.buffer[parser.idx] = 0;
584 
585                 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
586                 if (ret)
587                         goto out_put;
588         }
589 
590         ret = read;
591 
592  out_put:
593         trace_parser_put(&parser);
594 
595         return ret;
596 }
597 
598 static void *
599 t_next(struct seq_file *m, void *v, loff_t *pos)
600 {
601         struct ftrace_event_file *file = v;
602         struct ftrace_event_call *call;
603         struct trace_array *tr = m->private;
604 
605         (*pos)++;
606 
607         list_for_each_entry_continue(file, &tr->events, list) {
608                 call = file->event_call;
609                 /*
610                  * The ftrace subsystem is for showing formats only.
611                  * They can not be enabled or disabled via the event files.
612                  */
613                 if (call->class && call->class->reg)
614                         return file;
615         }
616 
617         return NULL;
618 }
619 
620 static void *t_start(struct seq_file *m, loff_t *pos)
621 {
622         struct ftrace_event_file *file;
623         struct trace_array *tr = m->private;
624         loff_t l;
625 
626         mutex_lock(&event_mutex);
627 
628         file = list_entry(&tr->events, struct ftrace_event_file, list);
629         for (l = 0; l <= *pos; ) {
630                 file = t_next(m, file, &l);
631                 if (!file)
632                         break;
633         }
634         return file;
635 }
636 
637 static void *
638 s_next(struct seq_file *m, void *v, loff_t *pos)
639 {
640         struct ftrace_event_file *file = v;
641         struct trace_array *tr = m->private;
642 
643         (*pos)++;
644 
645         list_for_each_entry_continue(file, &tr->events, list) {
646                 if (file->flags & FTRACE_EVENT_FL_ENABLED)
647                         return file;
648         }
649 
650         return NULL;
651 }
652 
653 static void *s_start(struct seq_file *m, loff_t *pos)
654 {
655         struct ftrace_event_file *file;
656         struct trace_array *tr = m->private;
657         loff_t l;
658 
659         mutex_lock(&event_mutex);
660 
661         file = list_entry(&tr->events, struct ftrace_event_file, list);
662         for (l = 0; l <= *pos; ) {
663                 file = s_next(m, file, &l);
664                 if (!file)
665                         break;
666         }
667         return file;
668 }
669 
670 static int t_show(struct seq_file *m, void *v)
671 {
672         struct ftrace_event_file *file = v;
673         struct ftrace_event_call *call = file->event_call;
674 
675         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
676                 seq_printf(m, "%s:", call->class->system);
677         seq_printf(m, "%s\n", call->name);
678 
679         return 0;
680 }
681 
682 static void t_stop(struct seq_file *m, void *p)
683 {
684         mutex_unlock(&event_mutex);
685 }
686 
687 static ssize_t
688 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
689                   loff_t *ppos)
690 {
691         struct ftrace_event_file *file;
692         unsigned long flags;
693         char buf[4] = "";
694 
695         mutex_lock(&event_mutex);
696         file = event_file_data(filp);
697         if (likely(file))
698                 flags = file->flags;
699         mutex_unlock(&event_mutex);
700 
701         if (!file)
702                 return -ENODEV;
703 
704         if (flags & FTRACE_EVENT_FL_ENABLED &&
705             !(flags & FTRACE_EVENT_FL_SOFT_DISABLED))
706                 strcpy(buf, "1");
707 
708         if (flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
709             flags & FTRACE_EVENT_FL_SOFT_MODE)
710                 strcat(buf, "*");
711 
712         strcat(buf, "\n");
713 
714         return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
715 }
716 
717 static ssize_t
718 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
719                    loff_t *ppos)
720 {
721         struct ftrace_event_file *file;
722         unsigned long val;
723         int ret;
724 
725         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
726         if (ret)
727                 return ret;
728 
729         ret = tracing_update_buffers();
730         if (ret < 0)
731                 return ret;
732 
733         switch (val) {
734         case 0:
735         case 1:
736                 ret = -ENODEV;
737                 mutex_lock(&event_mutex);
738                 file = event_file_data(filp);
739                 if (likely(file))
740                         ret = ftrace_event_enable_disable(file, val);
741                 mutex_unlock(&event_mutex);
742                 break;
743 
744         default:
745                 return -EINVAL;
746         }
747 
748         *ppos += cnt;
749 
750         return ret ? ret : cnt;
751 }
752 
753 static ssize_t
754 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
755                    loff_t *ppos)
756 {
757         const char set_to_char[4] = { '?', '', '1', 'X' };
758         struct ftrace_subsystem_dir *dir = filp->private_data;
759         struct event_subsystem *system = dir->subsystem;
760         struct ftrace_event_call *call;
761         struct ftrace_event_file *file;
762         struct trace_array *tr = dir->tr;
763         char buf[2];
764         int set = 0;
765         int ret;
766 
767         mutex_lock(&event_mutex);
768         list_for_each_entry(file, &tr->events, list) {
769                 call = file->event_call;
770                 if (!call->name || !call->class || !call->class->reg)
771                         continue;
772 
773                 if (system && strcmp(call->class->system, system->name) != 0)
774                         continue;
775 
776                 /*
777                  * We need to find out if all the events are set
778                  * or if all events or cleared, or if we have
779                  * a mixture.
780                  */
781                 set |= (1 << !!(file->flags & FTRACE_EVENT_FL_ENABLED));
782 
783                 /*
784                  * If we have a mixture, no need to look further.
785                  */
786                 if (set == 3)
787                         break;
788         }
789         mutex_unlock(&event_mutex);
790 
791         buf[0] = set_to_char[set];
792         buf[1] = '\n';
793 
794         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
795 
796         return ret;
797 }
798 
799 static ssize_t
800 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
801                     loff_t *ppos)
802 {
803         struct ftrace_subsystem_dir *dir = filp->private_data;
804         struct event_subsystem *system = dir->subsystem;
805         const char *name = NULL;
806         unsigned long val;
807         ssize_t ret;
808 
809         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
810         if (ret)
811                 return ret;
812 
813         ret = tracing_update_buffers();
814         if (ret < 0)
815                 return ret;
816 
817         if (val != 0 && val != 1)
818                 return -EINVAL;
819 
820         /*
821          * Opening of "enable" adds a ref count to system,
822          * so the name is safe to use.
823          */
824         if (system)
825                 name = system->name;
826 
827         ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
828         if (ret)
829                 goto out;
830 
831         ret = cnt;
832 
833 out:
834         *ppos += cnt;
835 
836         return ret;
837 }
838 
839 enum {
840         FORMAT_HEADER           = 1,
841         FORMAT_FIELD_SEPERATOR  = 2,
842         FORMAT_PRINTFMT         = 3,
843 };
844 
845 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
846 {
847         struct ftrace_event_call *call = event_file_data(m->private);
848         struct list_head *common_head = &ftrace_common_fields;
849         struct list_head *head = trace_get_fields(call);
850         struct list_head *node = v;
851 
852         (*pos)++;
853 
854         switch ((unsigned long)v) {
855         case FORMAT_HEADER:
856                 node = common_head;
857                 break;
858 
859         case FORMAT_FIELD_SEPERATOR:
860                 node = head;
861                 break;
862 
863         case FORMAT_PRINTFMT:
864                 /* all done */
865                 return NULL;
866         }
867 
868         node = node->prev;
869         if (node == common_head)
870                 return (void *)FORMAT_FIELD_SEPERATOR;
871         else if (node == head)
872                 return (void *)FORMAT_PRINTFMT;
873         else
874                 return node;
875 }
876 
877 static int f_show(struct seq_file *m, void *v)
878 {
879         struct ftrace_event_call *call = event_file_data(m->private);
880         struct ftrace_event_field *field;
881         const char *array_descriptor;
882 
883         switch ((unsigned long)v) {
884         case FORMAT_HEADER:
885                 seq_printf(m, "name: %s\n", call->name);
886                 seq_printf(m, "ID: %d\n", call->event.type);
887                 seq_printf(m, "format:\n");
888                 return 0;
889 
890         case FORMAT_FIELD_SEPERATOR:
891                 seq_putc(m, '\n');
892                 return 0;
893 
894         case FORMAT_PRINTFMT:
895                 seq_printf(m, "\nprint fmt: %s\n",
896                            call->print_fmt);
897                 return 0;
898         }
899 
900         field = list_entry(v, struct ftrace_event_field, link);
901         /*
902          * Smartly shows the array type(except dynamic array).
903          * Normal:
904          *      field:TYPE VAR
905          * If TYPE := TYPE[LEN], it is shown:
906          *      field:TYPE VAR[LEN]
907          */
908         array_descriptor = strchr(field->type, '[');
909 
910         if (!strncmp(field->type, "__data_loc", 10))
911                 array_descriptor = NULL;
912 
913         if (!array_descriptor)
914                 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
915                            field->type, field->name, field->offset,
916                            field->size, !!field->is_signed);
917         else
918                 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
919                            (int)(array_descriptor - field->type),
920                            field->type, field->name,
921                            array_descriptor, field->offset,
922                            field->size, !!field->is_signed);
923 
924         return 0;
925 }
926 
927 static void *f_start(struct seq_file *m, loff_t *pos)
928 {
929         void *p = (void *)FORMAT_HEADER;
930         loff_t l = 0;
931 
932         /* ->stop() is called even if ->start() fails */
933         mutex_lock(&event_mutex);
934         if (!event_file_data(m->private))
935                 return ERR_PTR(-ENODEV);
936 
937         while (l < *pos && p)
938                 p = f_next(m, p, &l);
939 
940         return p;
941 }
942 
943 static void f_stop(struct seq_file *m, void *p)
944 {
945         mutex_unlock(&event_mutex);
946 }
947 
948 static const struct seq_operations trace_format_seq_ops = {
949         .start          = f_start,
950         .next           = f_next,
951         .stop           = f_stop,
952         .show           = f_show,
953 };
954 
955 static int trace_format_open(struct inode *inode, struct file *file)
956 {
957         struct seq_file *m;
958         int ret;
959 
960         ret = seq_open(file, &trace_format_seq_ops);
961         if (ret < 0)
962                 return ret;
963 
964         m = file->private_data;
965         m->private = file;
966 
967         return 0;
968 }
969 
970 static ssize_t
971 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
972 {
973         int id = (long)event_file_data(filp);
974         char buf[32];
975         int len;
976 
977         if (*ppos)
978                 return 0;
979 
980         if (unlikely(!id))
981                 return -ENODEV;
982 
983         len = sprintf(buf, "%d\n", id);
984 
985         return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
986 }
987 
988 static ssize_t
989 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
990                   loff_t *ppos)
991 {
992         struct ftrace_event_call *call;
993         struct trace_seq *s;
994         int r = -ENODEV;
995 
996         if (*ppos)
997                 return 0;
998 
999         s = kmalloc(sizeof(*s), GFP_KERNEL);
1000 
1001         if (!s)
1002                 return -ENOMEM;
1003 
1004         trace_seq_init(s);
1005 
1006         mutex_lock(&event_mutex);
1007         call = event_file_data(filp);
1008         if (call)
1009                 print_event_filter(call, s);
1010         mutex_unlock(&event_mutex);
1011 
1012         if (call)
1013                 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1014 
1015         kfree(s);
1016 
1017         return r;
1018 }
1019 
1020 static ssize_t
1021 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1022                    loff_t *ppos)
1023 {
1024         struct ftrace_event_call *call;
1025         char *buf;
1026         int err = -ENODEV;
1027 
1028         if (cnt >= PAGE_SIZE)
1029                 return -EINVAL;
1030 
1031         buf = (char *)__get_free_page(GFP_TEMPORARY);
1032         if (!buf)
1033                 return -ENOMEM;
1034 
1035         if (copy_from_user(buf, ubuf, cnt)) {
1036                 free_page((unsigned long) buf);
1037                 return -EFAULT;
1038         }
1039         buf[cnt] = '\0';
1040 
1041         mutex_lock(&event_mutex);
1042         call = event_file_data(filp);
1043         if (call)
1044                 err = apply_event_filter(call, buf);
1045         mutex_unlock(&event_mutex);
1046 
1047         free_page((unsigned long) buf);
1048         if (err < 0)
1049                 return err;
1050 
1051         *ppos += cnt;
1052 
1053         return cnt;
1054 }
1055 
1056 static LIST_HEAD(event_subsystems);
1057 
1058 static int subsystem_open(struct inode *inode, struct file *filp)
1059 {
1060         struct event_subsystem *system = NULL;
1061         struct ftrace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1062         struct trace_array *tr;
1063         int ret;
1064 
1065         /* Make sure the system still exists */
1066         mutex_lock(&trace_types_lock);
1067         mutex_lock(&event_mutex);
1068         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1069                 list_for_each_entry(dir, &tr->systems, list) {
1070                         if (dir == inode->i_private) {
1071                                 /* Don't open systems with no events */
1072                                 if (dir->nr_events) {
1073                                         __get_system_dir(dir);
1074                                         system = dir->subsystem;
1075                                 }
1076                                 goto exit_loop;
1077                         }
1078                 }
1079         }
1080  exit_loop:
1081         mutex_unlock(&event_mutex);
1082         mutex_unlock(&trace_types_lock);
1083 
1084         if (!system)
1085                 return -ENODEV;
1086 
1087         /* Some versions of gcc think dir can be uninitialized here */
1088         WARN_ON(!dir);
1089 
1090         /* Still need to increment the ref count of the system */
1091         if (trace_array_get(tr) < 0) {
1092                 put_system(dir);
1093                 return -ENODEV;
1094         }
1095 
1096         ret = tracing_open_generic(inode, filp);
1097         if (ret < 0) {
1098                 trace_array_put(tr);
1099                 put_system(dir);
1100         }
1101 
1102         return ret;
1103 }
1104 
1105 static int system_tr_open(struct inode *inode, struct file *filp)
1106 {
1107         struct ftrace_subsystem_dir *dir;
1108         struct trace_array *tr = inode->i_private;
1109         int ret;
1110 
1111         if (trace_array_get(tr) < 0)
1112                 return -ENODEV;
1113 
1114         /* Make a temporary dir that has no system but points to tr */
1115         dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1116         if (!dir) {
1117                 trace_array_put(tr);
1118                 return -ENOMEM;
1119         }
1120 
1121         dir->tr = tr;
1122 
1123         ret = tracing_open_generic(inode, filp);
1124         if (ret < 0) {
1125                 trace_array_put(tr);
1126                 kfree(dir);
1127         }
1128 
1129         filp->private_data = dir;
1130 
1131         return ret;
1132 }
1133 
1134 static int subsystem_release(struct inode *inode, struct file *file)
1135 {
1136         struct ftrace_subsystem_dir *dir = file->private_data;
1137 
1138         trace_array_put(dir->tr);
1139 
1140         /*
1141          * If dir->subsystem is NULL, then this is a temporary
1142          * descriptor that was made for a trace_array to enable
1143          * all subsystems.
1144          */
1145         if (dir->subsystem)
1146                 put_system(dir);
1147         else
1148                 kfree(dir);
1149 
1150         return 0;
1151 }
1152 
1153 static ssize_t
1154 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1155                       loff_t *ppos)
1156 {
1157         struct ftrace_subsystem_dir *dir = filp->private_data;
1158         struct event_subsystem *system = dir->subsystem;
1159         struct trace_seq *s;
1160         int r;
1161 
1162         if (*ppos)
1163                 return 0;
1164 
1165         s = kmalloc(sizeof(*s), GFP_KERNEL);
1166         if (!s)
1167                 return -ENOMEM;
1168 
1169         trace_seq_init(s);
1170 
1171         print_subsystem_event_filter(system, s);
1172         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1173 
1174         kfree(s);
1175 
1176         return r;
1177 }
1178 
1179 static ssize_t
1180 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1181                        loff_t *ppos)
1182 {
1183         struct ftrace_subsystem_dir *dir = filp->private_data;
1184         char *buf;
1185         int err;
1186 
1187         if (cnt >= PAGE_SIZE)
1188                 return -EINVAL;
1189 
1190         buf = (char *)__get_free_page(GFP_TEMPORARY);
1191         if (!buf)
1192                 return -ENOMEM;
1193 
1194         if (copy_from_user(buf, ubuf, cnt)) {
1195                 free_page((unsigned long) buf);
1196                 return -EFAULT;
1197         }
1198         buf[cnt] = '\0';
1199 
1200         err = apply_subsystem_event_filter(dir, buf);
1201         free_page((unsigned long) buf);
1202         if (err < 0)
1203                 return err;
1204 
1205         *ppos += cnt;
1206 
1207         return cnt;
1208 }
1209 
1210 static ssize_t
1211 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1212 {
1213         int (*func)(struct trace_seq *s) = filp->private_data;
1214         struct trace_seq *s;
1215         int r;
1216 
1217         if (*ppos)
1218                 return 0;
1219 
1220         s = kmalloc(sizeof(*s), GFP_KERNEL);
1221         if (!s)
1222                 return -ENOMEM;
1223 
1224         trace_seq_init(s);
1225 
1226         func(s);
1227         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
1228 
1229         kfree(s);
1230 
1231         return r;
1232 }
1233 
1234 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1235 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1236 static int ftrace_event_release(struct inode *inode, struct file *file);
1237 
1238 static const struct seq_operations show_event_seq_ops = {
1239         .start = t_start,
1240         .next = t_next,
1241         .show = t_show,
1242         .stop = t_stop,
1243 };
1244 
1245 static const struct seq_operations show_set_event_seq_ops = {
1246         .start = s_start,
1247         .next = s_next,
1248         .show = t_show,
1249         .stop = t_stop,
1250 };
1251 
1252 static const struct file_operations ftrace_avail_fops = {
1253         .open = ftrace_event_avail_open,
1254         .read = seq_read,
1255         .llseek = seq_lseek,
1256         .release = seq_release,
1257 };
1258 
1259 static const struct file_operations ftrace_set_event_fops = {
1260         .open = ftrace_event_set_open,
1261         .read = seq_read,
1262         .write = ftrace_event_write,
1263         .llseek = seq_lseek,
1264         .release = ftrace_event_release,
1265 };
1266 
1267 static const struct file_operations ftrace_enable_fops = {
1268         .open = tracing_open_generic,
1269         .read = event_enable_read,
1270         .write = event_enable_write,
1271         .llseek = default_llseek,
1272 };
1273 
1274 static const struct file_operations ftrace_event_format_fops = {
1275         .open = trace_format_open,
1276         .read = seq_read,
1277         .llseek = seq_lseek,
1278         .release = seq_release,
1279 };
1280 
1281 static const struct file_operations ftrace_event_id_fops = {
1282         .read = event_id_read,
1283         .llseek = default_llseek,
1284 };
1285 
1286 static const struct file_operations ftrace_event_filter_fops = {
1287         .open = tracing_open_generic,
1288         .read = event_filter_read,
1289         .write = event_filter_write,
1290         .llseek = default_llseek,
1291 };
1292 
1293 static const struct file_operations ftrace_subsystem_filter_fops = {
1294         .open = subsystem_open,
1295         .read = subsystem_filter_read,
1296         .write = subsystem_filter_write,
1297         .llseek = default_llseek,
1298         .release = subsystem_release,
1299 };
1300 
1301 static const struct file_operations ftrace_system_enable_fops = {
1302         .open = subsystem_open,
1303         .read = system_enable_read,
1304         .write = system_enable_write,
1305         .llseek = default_llseek,
1306         .release = subsystem_release,
1307 };
1308 
1309 static const struct file_operations ftrace_tr_enable_fops = {
1310         .open = system_tr_open,
1311         .read = system_enable_read,
1312         .write = system_enable_write,
1313         .llseek = default_llseek,
1314         .release = subsystem_release,
1315 };
1316 
1317 static const struct file_operations ftrace_show_header_fops = {
1318         .open = tracing_open_generic,
1319         .read = show_header,
1320         .llseek = default_llseek,
1321 };
1322 
1323 static int
1324 ftrace_event_open(struct inode *inode, struct file *file,
1325                   const struct seq_operations *seq_ops)
1326 {
1327         struct seq_file *m;
1328         int ret;
1329 
1330         ret = seq_open(file, seq_ops);
1331         if (ret < 0)
1332                 return ret;
1333         m = file->private_data;
1334         /* copy tr over to seq ops */
1335         m->private = inode->i_private;
1336 
1337         return ret;
1338 }
1339 
1340 static int ftrace_event_release(struct inode *inode, struct file *file)
1341 {
1342         struct trace_array *tr = inode->i_private;
1343 
1344         trace_array_put(tr);
1345 
1346         return seq_release(inode, file);
1347 }
1348 
1349 static int
1350 ftrace_event_avail_open(struct inode *inode, struct file *file)
1351 {
1352         const struct seq_operations *seq_ops = &show_event_seq_ops;
1353 
1354         return ftrace_event_open(inode, file, seq_ops);
1355 }
1356 
1357 static int
1358 ftrace_event_set_open(struct inode *inode, struct file *file)
1359 {
1360         const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1361         struct trace_array *tr = inode->i_private;
1362         int ret;
1363 
1364         if (trace_array_get(tr) < 0)
1365                 return -ENODEV;
1366 
1367         if ((file->f_mode & FMODE_WRITE) &&
1368             (file->f_flags & O_TRUNC))
1369                 ftrace_clear_events(tr);
1370 
1371         ret = ftrace_event_open(inode, file, seq_ops);
1372         if (ret < 0)
1373                 trace_array_put(tr);
1374         return ret;
1375 }
1376 
1377 static struct event_subsystem *
1378 create_new_subsystem(const char *name)
1379 {
1380         struct event_subsystem *system;
1381 
1382         /* need to create new entry */
1383         system = kmalloc(sizeof(*system), GFP_KERNEL);
1384         if (!system)
1385                 return NULL;
1386 
1387         system->ref_count = 1;
1388 
1389         /* Only allocate if dynamic (kprobes and modules) */
1390         if (!core_kernel_data((unsigned long)name)) {
1391                 system->ref_count |= SYSTEM_FL_FREE_NAME;
1392                 system->name = kstrdup(name, GFP_KERNEL);
1393                 if (!system->name)
1394                         goto out_free;
1395         } else
1396                 system->name = name;
1397 
1398         system->filter = NULL;
1399 
1400         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1401         if (!system->filter)
1402                 goto out_free;
1403 
1404         list_add(&system->list, &event_subsystems);
1405 
1406         return system;
1407 
1408  out_free:
1409         if (system->ref_count & SYSTEM_FL_FREE_NAME)
1410                 kfree(system->name);
1411         kfree(system);
1412         return NULL;
1413 }
1414 
1415 static struct dentry *
1416 event_subsystem_dir(struct trace_array *tr, const char *name,
1417                     struct ftrace_event_file *file, struct dentry *parent)
1418 {
1419         struct ftrace_subsystem_dir *dir;
1420         struct event_subsystem *system;
1421         struct dentry *entry;
1422 
1423         /* First see if we did not already create this dir */
1424         list_for_each_entry(dir, &tr->systems, list) {
1425                 system = dir->subsystem;
1426                 if (strcmp(system->name, name) == 0) {
1427                         dir->nr_events++;
1428                         file->system = dir;
1429                         return dir->entry;
1430                 }
1431         }
1432 
1433         /* Now see if the system itself exists. */
1434         list_for_each_entry(system, &event_subsystems, list) {
1435                 if (strcmp(system->name, name) == 0)
1436                         break;
1437         }
1438         /* Reset system variable when not found */
1439         if (&system->list == &event_subsystems)
1440                 system = NULL;
1441 
1442         dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1443         if (!dir)
1444                 goto out_fail;
1445 
1446         if (!system) {
1447                 system = create_new_subsystem(name);
1448                 if (!system)
1449                         goto out_free;
1450         } else
1451                 __get_system(system);
1452 
1453         dir->entry = debugfs_create_dir(name, parent);
1454         if (!dir->entry) {
1455                 pr_warning("Failed to create system directory %s\n", name);
1456                 __put_system(system);
1457                 goto out_free;
1458         }
1459 
1460         dir->tr = tr;
1461         dir->ref_count = 1;
1462         dir->nr_events = 1;
1463         dir->subsystem = system;
1464         file->system = dir;
1465 
1466         entry = debugfs_create_file("filter", 0644, dir->entry, dir,
1467                                     &ftrace_subsystem_filter_fops);
1468         if (!entry) {
1469                 kfree(system->filter);
1470                 system->filter = NULL;
1471                 pr_warning("Could not create debugfs '%s/filter' entry\n", name);
1472         }
1473 
1474         trace_create_file("enable", 0644, dir->entry, dir,
1475                           &ftrace_system_enable_fops);
1476 
1477         list_add(&dir->list, &tr->systems);
1478 
1479         return dir->entry;
1480 
1481  out_free:
1482         kfree(dir);
1483  out_fail:
1484         /* Only print this message if failed on memory allocation */
1485         if (!dir || !system)
1486                 pr_warning("No memory to create event subsystem %s\n",
1487                            name);
1488         return NULL;
1489 }
1490 
1491 static int
1492 event_create_dir(struct dentry *parent,
1493                  struct ftrace_event_file *file,
1494                  const struct file_operations *id,
1495                  const struct file_operations *enable,
1496                  const struct file_operations *filter,
1497                  const struct file_operations *format)
1498 {
1499         struct ftrace_event_call *call = file->event_call;
1500         struct trace_array *tr = file->tr;
1501         struct list_head *head;
1502         struct dentry *d_events;
1503         int ret;
1504 
1505         /*
1506          * If the trace point header did not define TRACE_SYSTEM
1507          * then the system would be called "TRACE_SYSTEM".
1508          */
1509         if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1510                 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1511                 if (!d_events)
1512                         return -ENOMEM;
1513         } else
1514                 d_events = parent;
1515 
1516         file->dir = debugfs_create_dir(call->name, d_events);
1517         if (!file->dir) {
1518                 pr_warning("Could not create debugfs '%s' directory\n",
1519                            call->name);
1520                 return -1;
1521         }
1522 
1523         if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1524                 trace_create_file("enable", 0644, file->dir, file,
1525                                   enable);
1526 
1527 #ifdef CONFIG_PERF_EVENTS
1528         if (call->event.type && call->class->reg)
1529                 trace_create_file("id", 0444, file->dir,
1530                                   (void *)(long)call->event.type, id);
1531 #endif
1532 
1533         /*
1534          * Other events may have the same class. Only update
1535          * the fields if they are not already defined.
1536          */
1537         head = trace_get_fields(call);
1538         if (list_empty(head)) {
1539                 ret = call->class->define_fields(call);
1540                 if (ret < 0) {
1541                         pr_warning("Could not initialize trace point"
1542                                    " events/%s\n", call->name);
1543                         return -1;
1544                 }
1545         }
1546         trace_create_file("filter", 0644, file->dir, call,
1547                           filter);
1548 
1549         trace_create_file("format", 0444, file->dir, call,
1550                           format);
1551 
1552         return 0;
1553 }
1554 
1555 static void remove_event_from_tracers(struct ftrace_event_call *call)
1556 {
1557         struct ftrace_event_file *file;
1558         struct trace_array *tr;
1559 
1560         do_for_each_event_file_safe(tr, file) {
1561                 if (file->event_call != call)
1562                         continue;
1563 
1564                 remove_event_file_dir(file);
1565                 /*
1566                  * The do_for_each_event_file_safe() is
1567                  * a double loop. After finding the call for this
1568                  * trace_array, we use break to jump to the next
1569                  * trace_array.
1570                  */
1571                 break;
1572         } while_for_each_event_file();
1573 }
1574 
1575 static void event_remove(struct ftrace_event_call *call)
1576 {
1577         struct trace_array *tr;
1578         struct ftrace_event_file *file;
1579 
1580         do_for_each_event_file(tr, file) {
1581                 if (file->event_call != call)
1582                         continue;
1583                 ftrace_event_enable_disable(file, 0);
1584                 /*
1585                  * The do_for_each_event_file() is
1586                  * a double loop. After finding the call for this
1587                  * trace_array, we use break to jump to the next
1588                  * trace_array.
1589                  */
1590                 break;
1591         } while_for_each_event_file();
1592 
1593         if (call->event.funcs)
1594                 __unregister_ftrace_event(&call->event);
1595         remove_event_from_tracers(call);
1596         list_del(&call->list);
1597 }
1598 
1599 static int event_init(struct ftrace_event_call *call)
1600 {
1601         int ret = 0;
1602 
1603         if (WARN_ON(!call->name))
1604                 return -EINVAL;
1605 
1606         if (call->class->raw_init) {
1607                 ret = call->class->raw_init(call);
1608                 if (ret < 0 && ret != -ENOSYS)
1609                         pr_warn("Could not initialize trace events/%s\n",
1610                                 call->name);
1611         }
1612 
1613         return ret;
1614 }
1615 
1616 static int
1617 __register_event(struct ftrace_event_call *call, struct module *mod)
1618 {
1619         int ret;
1620 
1621         ret = event_init(call);
1622         if (ret < 0)
1623                 return ret;
1624 
1625         list_add(&call->list, &ftrace_events);
1626         call->mod = mod;
1627 
1628         return 0;
1629 }
1630 
1631 static struct ftrace_event_file *
1632 trace_create_new_event(struct ftrace_event_call *call,
1633                        struct trace_array *tr)
1634 {
1635         struct ftrace_event_file *file;
1636 
1637         file = kmem_cache_alloc(file_cachep, GFP_TRACE);
1638         if (!file)
1639                 return NULL;
1640 
1641         file->event_call = call;
1642         file->tr = tr;
1643         atomic_set(&file->sm_ref, 0);
1644         list_add(&file->list, &tr->events);
1645 
1646         return file;
1647 }
1648 
1649 /* Add an event to a trace directory */
1650 static int
1651 __trace_add_new_event(struct ftrace_event_call *call,
1652                       struct trace_array *tr,
1653                       const struct file_operations *id,
1654                       const struct file_operations *enable,
1655                       const struct file_operations *filter,
1656                       const struct file_operations *format)
1657 {
1658         struct ftrace_event_file *file;
1659 
1660         file = trace_create_new_event(call, tr);
1661         if (!file)
1662                 return -ENOMEM;
1663 
1664         return event_create_dir(tr->event_dir, file, id, enable, filter, format);
1665 }
1666 
1667 /*
1668  * Just create a decriptor for early init. A descriptor is required
1669  * for enabling events at boot. We want to enable events before
1670  * the filesystem is initialized.
1671  */
1672 static __init int
1673 __trace_early_add_new_event(struct ftrace_event_call *call,
1674                             struct trace_array *tr)
1675 {
1676         struct ftrace_event_file *file;
1677 
1678         file = trace_create_new_event(call, tr);
1679         if (!file)
1680                 return -ENOMEM;
1681 
1682         return 0;
1683 }
1684 
1685 struct ftrace_module_file_ops;
1686 static void __add_event_to_tracers(struct ftrace_event_call *call,
1687                                    struct ftrace_module_file_ops *file_ops);
1688 
1689 /* Add an additional event_call dynamically */
1690 int trace_add_event_call(struct ftrace_event_call *call)
1691 {
1692         int ret;
1693         mutex_lock(&trace_types_lock);
1694         mutex_lock(&event_mutex);
1695 
1696         ret = __register_event(call, NULL);
1697         if (ret >= 0)
1698                 __add_event_to_tracers(call, NULL);
1699 
1700         mutex_unlock(&event_mutex);
1701         mutex_unlock(&trace_types_lock);
1702         return ret;
1703 }
1704 
1705 /*
1706  * Must be called under locking of trace_types_lock, event_mutex and
1707  * trace_event_sem.
1708  */
1709 static void __trace_remove_event_call(struct ftrace_event_call *call)
1710 {
1711         event_remove(call);
1712         trace_destroy_fields(call);
1713         destroy_preds(call);
1714 }
1715 
1716 static int probe_remove_event_call(struct ftrace_event_call *call)
1717 {
1718         struct trace_array *tr;
1719         struct ftrace_event_file *file;
1720 
1721 #ifdef CONFIG_PERF_EVENTS
1722         if (call->perf_refcount)
1723                 return -EBUSY;
1724 #endif
1725         do_for_each_event_file(tr, file) {
1726                 if (file->event_call != call)
1727                         continue;
1728                 /*
1729                  * We can't rely on ftrace_event_enable_disable(enable => 0)
1730                  * we are going to do, FTRACE_EVENT_FL_SOFT_MODE can suppress
1731                  * TRACE_REG_UNREGISTER.
1732                  */
1733                 if (file->flags & FTRACE_EVENT_FL_ENABLED)
1734                         return -EBUSY;
1735                 /*
1736                  * The do_for_each_event_file_safe() is
1737                  * a double loop. After finding the call for this
1738                  * trace_array, we use break to jump to the next
1739                  * trace_array.
1740                  */
1741                 break;
1742         } while_for_each_event_file();
1743 
1744         __trace_remove_event_call(call);
1745 
1746         return 0;
1747 }
1748 
1749 /* Remove an event_call */
1750 int trace_remove_event_call(struct ftrace_event_call *call)
1751 {
1752         int ret;
1753 
1754         mutex_lock(&trace_types_lock);
1755         mutex_lock(&event_mutex);
1756         down_write(&trace_event_sem);
1757         ret = probe_remove_event_call(call);
1758         up_write(&trace_event_sem);
1759         mutex_unlock(&event_mutex);
1760         mutex_unlock(&trace_types_lock);
1761 
1762         return ret;
1763 }
1764 
1765 #define for_each_event(event, start, end)                       \
1766         for (event = start;                                     \
1767              (unsigned long)event < (unsigned long)end;         \
1768              event++)
1769 
1770 #ifdef CONFIG_MODULES
1771 
1772 static LIST_HEAD(ftrace_module_file_list);
1773 
1774 /*
1775  * Modules must own their file_operations to keep up with
1776  * reference counting.
1777  */
1778 struct ftrace_module_file_ops {
1779         struct list_head                list;
1780         struct module                   *mod;
1781         struct file_operations          id;
1782         struct file_operations          enable;
1783         struct file_operations          format;
1784         struct file_operations          filter;
1785 };
1786 
1787 static struct ftrace_module_file_ops *
1788 find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
1789 {
1790         /*
1791          * As event_calls are added in groups by module,
1792          * when we find one file_ops, we don't need to search for
1793          * each call in that module, as the rest should be the
1794          * same. Only search for a new one if the last one did
1795          * not match.
1796          */
1797         if (file_ops && mod == file_ops->mod)
1798                 return file_ops;
1799 
1800         list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1801                 if (file_ops->mod == mod)
1802                         return file_ops;
1803         }
1804         return NULL;
1805 }
1806 
1807 static struct ftrace_module_file_ops *
1808 trace_create_file_ops(struct module *mod)
1809 {
1810         struct ftrace_module_file_ops *file_ops;
1811 
1812         /*
1813          * This is a bit of a PITA. To allow for correct reference
1814          * counting, modules must "own" their file_operations.
1815          * To do this, we allocate the file operations that will be
1816          * used in the event directory.
1817          */
1818 
1819         file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1820         if (!file_ops)
1821                 return NULL;
1822 
1823         file_ops->mod = mod;
1824 
1825         file_ops->id = ftrace_event_id_fops;
1826         file_ops->id.owner = mod;
1827 
1828         file_ops->enable = ftrace_enable_fops;
1829         file_ops->enable.owner = mod;
1830 
1831         file_ops->filter = ftrace_event_filter_fops;
1832         file_ops->filter.owner = mod;
1833 
1834         file_ops->format = ftrace_event_format_fops;
1835         file_ops->format.owner = mod;
1836 
1837         list_add(&file_ops->list, &ftrace_module_file_list);
1838 
1839         return file_ops;
1840 }
1841 
1842 static void trace_module_add_events(struct module *mod)
1843 {
1844         struct ftrace_module_file_ops *file_ops = NULL;
1845         struct ftrace_event_call **call, **start, **end;
1846 
1847         start = mod->trace_events;
1848         end = mod->trace_events + mod->num_trace_events;
1849 
1850         if (start == end)
1851                 return;
1852 
1853         file_ops = trace_create_file_ops(mod);
1854         if (!file_ops)
1855                 return;
1856 
1857         for_each_event(call, start, end) {
1858                 __register_event(*call, mod);
1859                 __add_event_to_tracers(*call, file_ops);
1860         }
1861 }
1862 
1863 static void trace_module_remove_events(struct module *mod)
1864 {
1865         struct ftrace_module_file_ops *file_ops;
1866         struct ftrace_event_call *call, *p;
1867         bool clear_trace = false;
1868 
1869         down_write(&trace_event_sem);
1870         list_for_each_entry_safe(call, p, &ftrace_events, list) {
1871                 if (call->mod == mod) {
1872                         if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
1873                                 clear_trace = true;
1874                         __trace_remove_event_call(call);
1875                 }
1876         }
1877 
1878         /* Now free the file_operations */
1879         list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1880                 if (file_ops->mod == mod)
1881                         break;
1882         }
1883         if (&file_ops->list != &ftrace_module_file_list) {
1884                 list_del(&file_ops->list);
1885                 kfree(file_ops);
1886         }
1887         up_write(&trace_event_sem);
1888 
1889         /*
1890          * It is safest to reset the ring buffer if the module being unloaded
1891          * registered any events that were used. The only worry is if
1892          * a new module gets loaded, and takes on the same id as the events
1893          * of this module. When printing out the buffer, traced events left
1894          * over from this module may be passed to the new module events and
1895          * unexpected results may occur.
1896          */
1897         if (clear_trace)
1898                 tracing_reset_all_online_cpus();
1899 }
1900 
1901 static int trace_module_notify(struct notifier_block *self,
1902                                unsigned long val, void *data)
1903 {
1904         struct module *mod = data;
1905 
1906         mutex_lock(&trace_types_lock);
1907         mutex_lock(&event_mutex);
1908         switch (val) {
1909         case MODULE_STATE_COMING:
1910                 trace_module_add_events(mod);
1911                 break;
1912         case MODULE_STATE_GOING:
1913                 trace_module_remove_events(mod);
1914                 break;
1915         }
1916         mutex_unlock(&event_mutex);
1917         mutex_unlock(&trace_types_lock);
1918 
1919         return 0;
1920 }
1921 
1922 static int
1923 __trace_add_new_mod_event(struct ftrace_event_call *call,
1924                           struct trace_array *tr,
1925                           struct ftrace_module_file_ops *file_ops)
1926 {
1927         return __trace_add_new_event(call, tr,
1928                                      &file_ops->id, &file_ops->enable,
1929                                      &file_ops->filter, &file_ops->format);
1930 }
1931 
1932 #else
1933 static inline struct ftrace_module_file_ops *
1934 find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module *mod)
1935 {
1936         return NULL;
1937 }
1938 static inline int trace_module_notify(struct notifier_block *self,
1939                                       unsigned long val, void *data)
1940 {
1941         return 0;
1942 }
1943 static inline int
1944 __trace_add_new_mod_event(struct ftrace_event_call *call,
1945                           struct trace_array *tr,
1946                           struct ftrace_module_file_ops *file_ops)
1947 {
1948         return -ENODEV;
1949 }
1950 #endif /* CONFIG_MODULES */
1951 
1952 /* Create a new event directory structure for a trace directory. */
1953 static void
1954 __trace_add_event_dirs(struct trace_array *tr)
1955 {
1956         struct ftrace_module_file_ops *file_ops = NULL;
1957         struct ftrace_event_call *call;
1958         int ret;
1959 
1960         list_for_each_entry(call, &ftrace_events, list) {
1961                 if (call->mod) {
1962                         /*
1963                          * Directories for events by modules need to
1964                          * keep module ref counts when opened (as we don't
1965                          * want the module to disappear when reading one
1966                          * of these files). The file_ops keep account of
1967                          * the module ref count.
1968                          */
1969                         file_ops = find_ftrace_file_ops(file_ops, call->mod);
1970                         if (!file_ops)
1971                                 continue; /* Warn? */
1972                         ret = __trace_add_new_mod_event(call, tr, file_ops);
1973                         if (ret < 0)
1974                                 pr_warning("Could not create directory for event %s\n",
1975                                            call->name);
1976                         continue;
1977                 }
1978                 ret = __trace_add_new_event(call, tr,
1979                                             &ftrace_event_id_fops,
1980                                             &ftrace_enable_fops,
1981                                             &ftrace_event_filter_fops,
1982                                             &ftrace_event_format_fops);
1983                 if (ret < 0)
1984                         pr_warning("Could not create directory for event %s\n",
1985                                    call->name);
1986         }
1987 }
1988 
1989 #ifdef CONFIG_DYNAMIC_FTRACE
1990 
1991 /* Avoid typos */
1992 #define ENABLE_EVENT_STR        "enable_event"
1993 #define DISABLE_EVENT_STR       "disable_event"
1994 
1995 struct event_probe_data {
1996         struct ftrace_event_file        *file;
1997         unsigned long                   count;
1998         int                             ref;
1999         bool                            enable;
2000 };
2001 
2002 static struct ftrace_event_file *
2003 find_event_file(struct trace_array *tr, const char *system,  const char *event)
2004 {
2005         struct ftrace_event_file *file;
2006         struct ftrace_event_call *call;
2007 
2008         list_for_each_entry(file, &tr->events, list) {
2009 
2010                 call = file->event_call;
2011 
2012                 if (!call->name || !call->class || !call->class->reg)
2013                         continue;
2014 
2015                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
2016                         continue;
2017 
2018                 if (strcmp(event, call->name) == 0 &&
2019                     strcmp(system, call->class->system) == 0)
2020                         return file;
2021         }
2022         return NULL;
2023 }
2024 
2025 static void
2026 event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
2027 {
2028         struct event_probe_data **pdata = (struct event_probe_data **)_data;
2029         struct event_probe_data *data = *pdata;
2030 
2031         if (!data)
2032                 return;
2033 
2034         if (data->enable)
2035                 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
2036         else
2037                 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags);
2038 }
2039 
2040 static void
2041 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
2042 {
2043         struct event_probe_data **pdata = (struct event_probe_data **)_data;
2044         struct event_probe_data *data = *pdata;
2045 
2046         if (!data)
2047                 return;
2048 
2049         if (!data->count)
2050                 return;
2051 
2052         /* Skip if the event is in a state we want to switch to */
2053         if (data->enable == !(data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
2054                 return;
2055 
2056         if (data->count != -1)
2057                 (data->count)--;
2058 
2059         event_enable_probe(ip, parent_ip, _data);
2060 }
2061 
2062 static int
2063 event_enable_print(struct seq_file *m, unsigned long ip,
2064                       struct ftrace_probe_ops *ops, void *_data)
2065 {
2066         struct event_probe_data *data = _data;
2067 
2068         seq_printf(m, "%ps:", (void *)ip);
2069 
2070         seq_printf(m, "%s:%s:%s",
2071                    data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
2072                    data->file->event_call->class->system,
2073                    data->file->event_call->name);
2074 
2075         if (data->count == -1)
2076                 seq_printf(m, ":unlimited\n");
2077         else
2078                 seq_printf(m, ":count=%ld\n", data->count);
2079 
2080         return 0;
2081 }
2082 
2083 static int
2084 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
2085                   void **_data)
2086 {
2087         struct event_probe_data **pdata = (struct event_probe_data **)_data;
2088         struct event_probe_data *data = *pdata;
2089 
2090         data->ref++;
2091         return 0;
2092 }
2093 
2094 static void
2095 event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
2096                   void **_data)
2097 {
2098         struct event_probe_data **pdata = (struct event_probe_data **)_data;
2099         struct event_probe_data *data = *pdata;
2100 
2101         if (WARN_ON_ONCE(data->ref <= 0))
2102                 return;
2103 
2104         data->ref--;
2105         if (!data->ref) {
2106                 /* Remove the SOFT_MODE flag */
2107                 __ftrace_event_enable_disable(data->file, 0, 1);
2108                 module_put(data->file->event_call->mod);
2109                 kfree(data);
2110         }
2111         *pdata = NULL;
2112 }
2113 
2114 static struct ftrace_probe_ops event_enable_probe_ops = {
2115         .func                   = event_enable_probe,
2116         .print                  = event_enable_print,
2117         .init                   = event_enable_init,
2118         .free                   = event_enable_free,
2119 };
2120 
2121 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2122         .func                   = event_enable_count_probe,
2123         .print                  = event_enable_print,
2124         .init                   = event_enable_init,
2125         .free                   = event_enable_free,
2126 };
2127 
2128 static struct ftrace_probe_ops event_disable_probe_ops = {
2129         .func                   = event_enable_probe,
2130         .print                  = event_enable_print,
2131         .init                   = event_enable_init,
2132         .free                   = event_enable_free,
2133 };
2134 
2135 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2136         .func                   = event_enable_count_probe,
2137         .print                  = event_enable_print,
2138         .init                   = event_enable_init,
2139         .free                   = event_enable_free,
2140 };
2141 
2142 static int
2143 event_enable_func(struct ftrace_hash *hash,
2144                   char *glob, char *cmd, char *param, int enabled)
2145 {
2146         struct trace_array *tr = top_trace_array();
2147         struct ftrace_event_file *file;
2148         struct ftrace_probe_ops *ops;
2149         struct event_probe_data *data;
2150         const char *system;
2151         const char *event;
2152         char *number;
2153         bool enable;
2154         int ret;
2155 
2156         /* hash funcs only work with set_ftrace_filter */
2157         if (!enabled || !param)
2158                 return -EINVAL;
2159 
2160         system = strsep(&param, ":");
2161         if (!param)
2162                 return -EINVAL;
2163 
2164         event = strsep(&param, ":");
2165 
2166         mutex_lock(&event_mutex);
2167 
2168         ret = -EINVAL;
2169         file = find_event_file(tr, system, event);
2170         if (!file)
2171                 goto out;
2172 
2173         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2174 
2175         if (enable)
2176                 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2177         else
2178                 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2179 
2180         if (glob[0] == '!') {
2181                 unregister_ftrace_function_probe_func(glob+1, ops);
2182                 ret = 0;
2183                 goto out;
2184         }
2185 
2186         ret = -ENOMEM;
2187         data = kzalloc(sizeof(*data), GFP_KERNEL);
2188         if (!data)
2189                 goto out;
2190 
2191         data->enable = enable;
2192         data->count = -1;
2193         data->file = file;
2194 
2195         if (!param)
2196                 goto out_reg;
2197 
2198         number = strsep(&param, ":");
2199 
2200         ret = -EINVAL;
2201         if (!strlen(number))
2202                 goto out_free;
2203 
2204         /*
2205          * We use the callback data field (which is a pointer)
2206          * as our counter.
2207          */
2208         ret = kstrtoul(number, 0, &data->count);
2209         if (ret)
2210                 goto out_free;
2211 
2212  out_reg:
2213         /* Don't let event modules unload while probe registered */
2214         ret = try_module_get(file->event_call->mod);
2215         if (!ret) {
2216                 ret = -EBUSY;
2217                 goto out_free;
2218         }
2219 
2220         ret = __ftrace_event_enable_disable(file, 1, 1);
2221         if (ret < 0)
2222                 goto out_put;
2223         ret = register_ftrace_function_probe(glob, ops, data);
2224         /*
2225          * The above returns on success the # of functions enabled,
2226          * but if it didn't find any functions it returns zero.
2227          * Consider no functions a failure too.
2228          */
2229         if (!ret) {
2230                 ret = -ENOENT;
2231                 goto out_disable;
2232         } else if (ret < 0)
2233                 goto out_disable;
2234         /* Just return zero, not the number of enabled functions */
2235         ret = 0;
2236  out:
2237         mutex_unlock(&event_mutex);
2238         return ret;
2239 
2240  out_disable:
2241         __ftrace_event_enable_disable(file, 0, 1);
2242  out_put:
2243         module_put(file->event_call->mod);
2244  out_free:
2245         kfree(data);
2246         goto out;
2247 }
2248 
2249 static struct ftrace_func_command event_enable_cmd = {
2250         .name                   = ENABLE_EVENT_STR,
2251         .func                   = event_enable_func,
2252 };
2253 
2254 static struct ftrace_func_command event_disable_cmd = {
2255         .name                   = DISABLE_EVENT_STR,
2256         .func                   = event_enable_func,
2257 };
2258 
2259 static __init int register_event_cmds(void)
2260 {
2261         int ret;
2262 
2263         ret = register_ftrace_command(&event_enable_cmd);
2264         if (WARN_ON(ret < 0))
2265                 return ret;
2266         ret = register_ftrace_command(&event_disable_cmd);
2267         if (WARN_ON(ret < 0))
2268                 unregister_ftrace_command(&event_enable_cmd);
2269         return ret;
2270 }
2271 #else
2272 static inline int register_event_cmds(void) { return 0; }
2273 #endif /* CONFIG_DYNAMIC_FTRACE */
2274 
2275 /*
2276  * The top level array has already had its ftrace_event_file
2277  * descriptors created in order to allow for early events to
2278  * be recorded. This function is called after the debugfs has been
2279  * initialized, and we now have to create the files associated
2280  * to the events.
2281  */
2282 static __init void
2283 __trace_early_add_event_dirs(struct trace_array *tr)
2284 {
2285         struct ftrace_event_file *file;
2286         int ret;
2287 
2288 
2289         list_for_each_entry(file, &tr->events, list) {
2290                 ret = event_create_dir(tr->event_dir, file,
2291                                        &ftrace_event_id_fops,
2292                                        &ftrace_enable_fops,
2293                                        &ftrace_event_filter_fops,
2294                                        &ftrace_event_format_fops);
2295                 if (ret < 0)
2296                         pr_warning("Could not create directory for event %s\n",
2297                                    file->event_call->name);
2298         }
2299 }
2300 
2301 /*
2302  * For early boot up, the top trace array requires to have
2303  * a list of events that can be enabled. This must be done before
2304  * the filesystem is set up in order to allow events to be traced
2305  * early.
2306  */
2307 static __init void
2308 __trace_early_add_events(struct trace_array *tr)
2309 {
2310         struct ftrace_event_call *call;
2311         int ret;
2312 
2313         list_for_each_entry(call, &ftrace_events, list) {
2314                 /* Early boot up should not have any modules loaded */
2315                 if (WARN_ON_ONCE(call->mod))
2316                         continue;
2317 
2318                 ret = __trace_early_add_new_event(call, tr);
2319                 if (ret < 0)
2320                         pr_warning("Could not create early event %s\n",
2321                                    call->name);
2322         }
2323 }
2324 
2325 /* Remove the event directory structure for a trace directory. */
2326 static void
2327 __trace_remove_event_dirs(struct trace_array *tr)
2328 {
2329         struct ftrace_event_file *file, *next;
2330 
2331         list_for_each_entry_safe(file, next, &tr->events, list)
2332                 remove_event_file_dir(file);
2333 }
2334 
2335 static void
2336 __add_event_to_tracers(struct ftrace_event_call *call,
2337                        struct ftrace_module_file_ops *file_ops)
2338 {
2339         struct trace_array *tr;
2340 
2341         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2342                 if (file_ops)
2343                         __trace_add_new_mod_event(call, tr, file_ops);
2344                 else
2345                         __trace_add_new_event(call, tr,
2346                                               &ftrace_event_id_fops,
2347                                               &ftrace_enable_fops,
2348                                               &ftrace_event_filter_fops,
2349                                               &ftrace_event_format_fops);
2350         }
2351 }
2352 
2353 static struct notifier_block trace_module_nb = {
2354         .notifier_call = trace_module_notify,
2355         .priority = 0,
2356 };
2357 
2358 extern struct ftrace_event_call *__start_ftrace_events[];
2359 extern struct ftrace_event_call *__stop_ftrace_events[];
2360 
2361 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2362 
2363 static __init int setup_trace_event(char *str)
2364 {
2365         strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2366         ring_buffer_expanded = true;
2367         tracing_selftest_disabled = true;
2368 
2369         return 1;
2370 }
2371 __setup("trace_event=", setup_trace_event);
2372 
2373 /* Expects to have event_mutex held when called */
2374 static int
2375 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2376 {
2377         struct dentry *d_events;
2378         struct dentry *entry;
2379 
2380         entry = debugfs_create_file("set_event", 0644, parent,
2381                                     tr, &ftrace_set_event_fops);
2382         if (!entry) {
2383                 pr_warning("Could not create debugfs 'set_event' entry\n");
2384                 return -ENOMEM;
2385         }
2386 
2387         d_events = debugfs_create_dir("events", parent);
2388         if (!d_events) {
2389                 pr_warning("Could not create debugfs 'events' directory\n");
2390                 return -ENOMEM;
2391         }
2392 
2393         /* ring buffer internal formats */
2394         trace_create_file("header_page", 0444, d_events,
2395                           ring_buffer_print_page_header,
2396                           &ftrace_show_header_fops);
2397 
2398         trace_create_file("header_event", 0444, d_events,
2399                           ring_buffer_print_entry_header,
2400                           &ftrace_show_header_fops);
2401 
2402         trace_create_file("enable", 0644, d_events,
2403                           tr, &ftrace_tr_enable_fops);
2404 
2405         tr->event_dir = d_events;
2406 
2407         return 0;
2408 }
2409 
2410 /**
2411  * event_trace_add_tracer - add a instance of a trace_array to events
2412  * @parent: The parent dentry to place the files/directories for events in
2413  * @tr: The trace array associated with these events
2414  *
2415  * When a new instance is created, it needs to set up its events
2416  * directory, as well as other files associated with events. It also
2417  * creates the event hierachry in the @parent/events directory.
2418  *
2419  * Returns 0 on success.
2420  */
2421 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2422 {
2423         int ret;
2424 
2425         mutex_lock(&event_mutex);
2426 
2427         ret = create_event_toplevel_files(parent, tr);
2428         if (ret)
2429                 goto out_unlock;
2430 
2431         down_write(&trace_event_sem);
2432         __trace_add_event_dirs(tr);
2433         up_write(&trace_event_sem);
2434 
2435  out_unlock:
2436         mutex_unlock(&event_mutex);
2437 
2438         return ret;
2439 }
2440 
2441 /*
2442  * The top trace array already had its file descriptors created.
2443  * Now the files themselves need to be created.
2444  */
2445 static __init int
2446 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2447 {
2448         int ret;
2449 
2450         mutex_lock(&event_mutex);
2451 
2452         ret = create_event_toplevel_files(parent, tr);
2453         if (ret)
2454                 goto out_unlock;
2455 
2456         down_write(&trace_event_sem);
2457         __trace_early_add_event_dirs(tr);
2458         up_write(&trace_event_sem);
2459 
2460  out_unlock:
2461         mutex_unlock(&event_mutex);
2462 
2463         return ret;
2464 }
2465 
2466 int event_trace_del_tracer(struct trace_array *tr)
2467 {
2468         mutex_lock(&event_mutex);
2469 
2470         /* Disable any running events */
2471         __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
2472 
2473         down_write(&trace_event_sem);
2474         __trace_remove_event_dirs(tr);
2475         debugfs_remove_recursive(tr->event_dir);
2476         up_write(&trace_event_sem);
2477 
2478         tr->event_dir = NULL;
2479 
2480         mutex_unlock(&event_mutex);
2481 
2482         return 0;
2483 }
2484 
2485 static __init int event_trace_memsetup(void)
2486 {
2487         field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
2488         file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC);
2489         return 0;
2490 }
2491 
2492 static __init int event_trace_enable(void)
2493 {
2494         struct trace_array *tr = top_trace_array();
2495         struct ftrace_event_call **iter, *call;
2496         char *buf = bootup_event_buf;
2497         char *token;
2498         int ret;
2499 
2500         for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
2501 
2502                 call = *iter;
2503                 ret = event_init(call);
2504                 if (!ret)
2505                         list_add(&call->list, &ftrace_events);
2506         }
2507 
2508         /*
2509          * We need the top trace array to have a working set of trace
2510          * points at early init, before the debug files and directories
2511          * are created. Create the file entries now, and attach them
2512          * to the actual file dentries later.
2513          */
2514         __trace_early_add_events(tr);
2515 
2516         while (true) {
2517                 token = strsep(&buf, ",");
2518 
2519                 if (!token)
2520                         break;
2521                 if (!*token)
2522                         continue;
2523 
2524                 ret = ftrace_set_clr_event(tr, token, 1);
2525                 if (ret)
2526                         pr_warn("Failed to enable trace event: %s\n", token);
2527         }
2528 
2529         trace_printk_start_comm();
2530 
2531         register_event_cmds();
2532 
2533         return 0;
2534 }
2535 
2536 static __init int event_trace_init(void)
2537 {
2538         struct trace_array *tr;
2539         struct dentry *d_tracer;
2540         struct dentry *entry;
2541         int ret;
2542 
2543         tr = top_trace_array();
2544 
2545         d_tracer = tracing_init_dentry();
2546         if (!d_tracer)
2547                 return 0;
2548 
2549         entry = debugfs_create_file("available_events", 0444, d_tracer,
2550                                     tr, &ftrace_avail_fops);
2551         if (!entry)
2552                 pr_warning("Could not create debugfs "
2553                            "'available_events' entry\n");
2554 
2555         if (trace_define_common_fields())
2556                 pr_warning("tracing: Failed to allocate common fields");
2557 
2558         ret = early_event_add_tracer(d_tracer, tr);
2559         if (ret)
2560                 return ret;
2561 
2562         ret = register_module_notifier(&trace_module_nb);
2563         if (ret)
2564                 pr_warning("Failed to register trace events module notifier\n");
2565 
2566         return 0;
2567 }
2568 early_initcall(event_trace_memsetup);
2569 core_initcall(event_trace_enable);
2570 fs_initcall(event_trace_init);
2571 
2572 #ifdef CONFIG_FTRACE_STARTUP_TEST
2573 
2574 static DEFINE_SPINLOCK(test_spinlock);
2575 static DEFINE_SPINLOCK(test_spinlock_irq);
2576 static DEFINE_MUTEX(test_mutex);
2577 
2578 static __init void test_work(struct work_struct *dummy)
2579 {
2580         spin_lock(&test_spinlock);
2581         spin_lock_irq(&test_spinlock_irq);
2582         udelay(1);
2583         spin_unlock_irq(&test_spinlock_irq);
2584         spin_unlock(&test_spinlock);
2585 
2586         mutex_lock(&test_mutex);
2587         msleep(1);
2588         mutex_unlock(&test_mutex);
2589 }
2590 
2591 static __init int event_test_thread(void *unused)
2592 {
2593         void *test_malloc;
2594 
2595         test_malloc = kmalloc(1234, GFP_KERNEL);
2596         if (!test_malloc)
2597                 pr_info("failed to kmalloc\n");
2598 
2599         schedule_on_each_cpu(test_work);
2600 
2601         kfree(test_malloc);
2602 
2603         set_current_state(TASK_INTERRUPTIBLE);
2604         while (!kthread_should_stop())
2605                 schedule();
2606 
2607         return 0;
2608 }
2609 
2610 /*
2611  * Do various things that may trigger events.
2612  */
2613 static __init void event_test_stuff(void)
2614 {
2615         struct task_struct *test_thread;
2616 
2617         test_thread = kthread_run(event_test_thread, NULL, "test-events");
2618         msleep(1);
2619         kthread_stop(test_thread);
2620 }
2621 
2622 /*
2623  * For every trace event defined, we will test each trace point separately,
2624  * and then by groups, and finally all trace points.
2625  */
2626 static __init void event_trace_self_tests(void)
2627 {
2628         struct ftrace_subsystem_dir *dir;
2629         struct ftrace_event_file *file;
2630         struct ftrace_event_call *call;
2631         struct event_subsystem *system;
2632         struct trace_array *tr;
2633         int ret;
2634 
2635         tr = top_trace_array();
2636 
2637         pr_info("Running tests on trace events:\n");
2638 
2639         list_for_each_entry(file, &tr->events, list) {
2640 
2641                 call = file->event_call;
2642 
2643                 /* Only test those that have a probe */
2644                 if (!call->class || !call->class->probe)
2645                         continue;
2646 
2647 /*
2648  * Testing syscall events here is pretty useless, but
2649  * we still do it if configured. But this is time consuming.
2650  * What we really need is a user thread to perform the
2651  * syscalls as we test.
2652  */
2653 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
2654                 if (call->class->system &&
2655                     strcmp(call->class->system, "syscalls") == 0)
2656                         continue;
2657 #endif
2658 
2659                 pr_info("Testing event %s: ", call->name);
2660 
2661                 /*
2662                  * If an event is already enabled, someone is using
2663                  * it and the self test should not be on.
2664                  */
2665                 if (file->flags & FTRACE_EVENT_FL_ENABLED) {
2666                         pr_warning("Enabled event during self test!\n");
2667                         WARN_ON_ONCE(1);
2668                         continue;
2669                 }
2670 
2671                 ftrace_event_enable_disable(file, 1);
2672                 event_test_stuff();
2673                 ftrace_event_enable_disable(file, 0);
2674 
2675                 pr_cont("OK\n");
2676         }
2677 
2678         /* Now test at the sub system level */
2679 
2680         pr_info("Running tests on trace event systems:\n");
2681 
2682         list_for_each_entry(dir, &tr->systems, list) {
2683 
2684                 system = dir->subsystem;
2685 
2686                 /* the ftrace system is special, skip it */
2687                 if (strcmp(system->name, "ftrace") == 0)
2688                         continue;
2689 
2690                 pr_info("Testing event system %s: ", system->name);
2691 
2692                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
2693                 if (WARN_ON_ONCE(ret)) {
2694                         pr_warning("error enabling system %s\n",
2695                                    system->name);
2696                         continue;
2697                 }
2698 
2699                 event_test_stuff();
2700 
2701                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
2702                 if (WARN_ON_ONCE(ret)) {
2703                         pr_warning("error disabling system %s\n",
2704                                    system->name);
2705                         continue;
2706                 }
2707 
2708                 pr_cont("OK\n");
2709         }
2710 
2711         /* Test with all events enabled */
2712 
2713         pr_info("Running tests on all trace events:\n");
2714         pr_info("Testing all events: ");
2715 
2716         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
2717         if (WARN_ON_ONCE(ret)) {
2718                 pr_warning("error enabling all events\n");
2719                 return;
2720         }
2721 
2722         event_test_stuff();
2723 
2724         /* reset sysname */
2725         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
2726         if (WARN_ON_ONCE(ret)) {
2727                 pr_warning("error disabling all events\n");
2728                 return;
2729         }
2730 
2731         pr_cont("OK\n");
2732 }
2733 
2734 #ifdef CONFIG_FUNCTION_TRACER
2735 
2736 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
2737 
2738 static void
2739 function_test_events_call(unsigned long ip, unsigned long parent_ip,
2740                           struct ftrace_ops *op, struct pt_regs *pt_regs)
2741 {
2742         struct ring_buffer_event *event;
2743         struct ring_buffer *buffer;
2744         struct ftrace_entry *entry;
2745         unsigned long flags;
2746         long disabled;
2747         int cpu;
2748         int pc;
2749 
2750         pc = preempt_count();
2751         preempt_disable_notrace();
2752         cpu = raw_smp_processor_id();
2753         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
2754 
2755         if (disabled != 1)
2756                 goto out;
2757 
2758         local_save_flags(flags);
2759 
2760         event = trace_current_buffer_lock_reserve(&buffer,
2761                                                   TRACE_FN, sizeof(*entry),
2762                                                   flags, pc);
2763         if (!event)
2764                 goto out;
2765         entry   = ring_buffer_event_data(event);
2766         entry->ip                       = ip;
2767         entry->parent_ip                = parent_ip;
2768 
2769         trace_buffer_unlock_commit(buffer, event, flags, pc);
2770 
2771  out:
2772         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
2773         preempt_enable_notrace();
2774 }
2775 
2776 static struct ftrace_ops trace_ops __initdata  =
2777 {
2778         .func = function_test_events_call,
2779         .flags = FTRACE_OPS_FL_RECURSION_SAFE,
2780 };
2781 
2782 static __init void event_trace_self_test_with_function(void)
2783 {
2784         int ret;
2785         ret = register_ftrace_function(&trace_ops);
2786         if (WARN_ON(ret < 0)) {
2787                 pr_info("Failed to enable function tracer for event tests\n");
2788                 return;
2789         }
2790         pr_info("Running tests again, along with the function tracer\n");
2791         event_trace_self_tests();
2792         unregister_ftrace_function(&trace_ops);
2793 }
2794 #else
2795 static __init void event_trace_self_test_with_function(void)
2796 {
2797 }
2798 #endif
2799 
2800 static __init int event_trace_self_tests_init(void)
2801 {
2802         if (!tracing_selftest_disabled) {
2803                 event_trace_self_tests();
2804                 event_trace_self_test_with_function();
2805         }
2806 
2807         return 0;
2808 }
2809 
2810 late_initcall(event_trace_self_tests_init);
2811 
2812 #endif
2813 

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