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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 #define pr_fmt(fmt) fmt
 12 
 13 #include <linux/workqueue.h>
 14 #include <linux/spinlock.h>
 15 #include <linux/kthread.h>
 16 #include <linux/tracefs.h>
 17 #include <linux/uaccess.h>
 18 #include <linux/module.h>
 19 #include <linux/ctype.h>
 20 #include <linux/sort.h>
 21 #include <linux/slab.h>
 22 #include <linux/delay.h>
 23 
 24 #include <trace/events/sched.h>
 25 
 26 #include <asm/setup.h>
 27 
 28 #include "trace_output.h"
 29 
 30 #undef TRACE_SYSTEM
 31 #define TRACE_SYSTEM "TRACE_SYSTEM"
 32 
 33 DEFINE_MUTEX(event_mutex);
 34 
 35 LIST_HEAD(ftrace_events);
 36 static LIST_HEAD(ftrace_generic_fields);
 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 static inline int system_refcount(struct event_subsystem *system)
 45 {
 46         return system->ref_count;
 47 }
 48 
 49 static int system_refcount_inc(struct event_subsystem *system)
 50 {
 51         return system->ref_count++;
 52 }
 53 
 54 static int system_refcount_dec(struct event_subsystem *system)
 55 {
 56         return --system->ref_count;
 57 }
 58 
 59 /* Double loops, do not use break, only goto's work */
 60 #define do_for_each_event_file(tr, file)                        \
 61         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
 62                 list_for_each_entry(file, &tr->events, list)
 63 
 64 #define do_for_each_event_file_safe(tr, file)                   \
 65         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
 66                 struct trace_event_file *___n;                          \
 67                 list_for_each_entry_safe(file, ___n, &tr->events, list)
 68 
 69 #define while_for_each_event_file()             \
 70         }
 71 
 72 static struct list_head *
 73 trace_get_fields(struct trace_event_call *event_call)
 74 {
 75         if (!event_call->class->get_fields)
 76                 return &event_call->class->fields;
 77         return event_call->class->get_fields(event_call);
 78 }
 79 
 80 static struct ftrace_event_field *
 81 __find_event_field(struct list_head *head, char *name)
 82 {
 83         struct ftrace_event_field *field;
 84 
 85         list_for_each_entry(field, head, link) {
 86                 if (!strcmp(field->name, name))
 87                         return field;
 88         }
 89 
 90         return NULL;
 91 }
 92 
 93 struct ftrace_event_field *
 94 trace_find_event_field(struct trace_event_call *call, char *name)
 95 {
 96         struct ftrace_event_field *field;
 97         struct list_head *head;
 98 
 99         head = trace_get_fields(call);
100         field = __find_event_field(head, name);
101         if (field)
102                 return field;
103 
104         field = __find_event_field(&ftrace_generic_fields, name);
105         if (field)
106                 return field;
107 
108         return __find_event_field(&ftrace_common_fields, name);
109 }
110 
111 static int __trace_define_field(struct list_head *head, const char *type,
112                                 const char *name, int offset, int size,
113                                 int is_signed, int filter_type)
114 {
115         struct ftrace_event_field *field;
116 
117         field = kmem_cache_alloc(field_cachep, GFP_TRACE);
118         if (!field)
119                 return -ENOMEM;
120 
121         field->name = name;
122         field->type = type;
123 
124         if (filter_type == FILTER_OTHER)
125                 field->filter_type = filter_assign_type(type);
126         else
127                 field->filter_type = filter_type;
128 
129         field->offset = offset;
130         field->size = size;
131         field->is_signed = is_signed;
132 
133         list_add(&field->link, head);
134 
135         return 0;
136 }
137 
138 int trace_define_field(struct trace_event_call *call, const char *type,
139                        const char *name, int offset, int size, int is_signed,
140                        int filter_type)
141 {
142         struct list_head *head;
143 
144         if (WARN_ON(!call->class))
145                 return 0;
146 
147         head = trace_get_fields(call);
148         return __trace_define_field(head, type, name, offset, size,
149                                     is_signed, filter_type);
150 }
151 EXPORT_SYMBOL_GPL(trace_define_field);
152 
153 #define __generic_field(type, item, filter_type)                        \
154         ret = __trace_define_field(&ftrace_generic_fields, #type,       \
155                                    #item, 0, 0, is_signed_type(type),   \
156                                    filter_type);                        \
157         if (ret)                                                        \
158                 return ret;
159 
160 #define __common_field(type, item)                                      \
161         ret = __trace_define_field(&ftrace_common_fields, #type,        \
162                                    "common_" #item,                     \
163                                    offsetof(typeof(ent), item),         \
164                                    sizeof(ent.item),                    \
165                                    is_signed_type(type), FILTER_OTHER); \
166         if (ret)                                                        \
167                 return ret;
168 
169 static int trace_define_generic_fields(void)
170 {
171         int ret;
172 
173         __generic_field(int, CPU, FILTER_CPU);
174         __generic_field(int, cpu, FILTER_CPU);
175         __generic_field(char *, COMM, FILTER_COMM);
176         __generic_field(char *, comm, FILTER_COMM);
177 
178         return ret;
179 }
180 
181 static int trace_define_common_fields(void)
182 {
183         int ret;
184         struct trace_entry ent;
185 
186         __common_field(unsigned short, type);
187         __common_field(unsigned char, flags);
188         __common_field(unsigned char, preempt_count);
189         __common_field(int, pid);
190 
191         return ret;
192 }
193 
194 static void trace_destroy_fields(struct trace_event_call *call)
195 {
196         struct ftrace_event_field *field, *next;
197         struct list_head *head;
198 
199         head = trace_get_fields(call);
200         list_for_each_entry_safe(field, next, head, link) {
201                 list_del(&field->link);
202                 kmem_cache_free(field_cachep, field);
203         }
204 }
205 
206 /*
207  * run-time version of trace_event_get_offsets_<call>() that returns the last
208  * accessible offset of trace fields excluding __dynamic_array bytes
209  */
210 int trace_event_get_offsets(struct trace_event_call *call)
211 {
212         struct ftrace_event_field *tail;
213         struct list_head *head;
214 
215         head = trace_get_fields(call);
216         /*
217          * head->next points to the last field with the largest offset,
218          * since it was added last by trace_define_field()
219          */
220         tail = list_first_entry(head, struct ftrace_event_field, link);
221         return tail->offset + tail->size;
222 }
223 
224 int trace_event_raw_init(struct trace_event_call *call)
225 {
226         int id;
227 
228         id = register_trace_event(&call->event);
229         if (!id)
230                 return -ENODEV;
231 
232         return 0;
233 }
234 EXPORT_SYMBOL_GPL(trace_event_raw_init);
235 
236 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
237 {
238         struct trace_array *tr = trace_file->tr;
239         struct trace_array_cpu *data;
240         struct trace_pid_list *pid_list;
241 
242         pid_list = rcu_dereference_sched(tr->filtered_pids);
243         if (!pid_list)
244                 return false;
245 
246         data = this_cpu_ptr(tr->trace_buffer.data);
247 
248         return data->ignore_pid;
249 }
250 EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
251 
252 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
253                                  struct trace_event_file *trace_file,
254                                  unsigned long len)
255 {
256         struct trace_event_call *event_call = trace_file->event_call;
257 
258         if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
259             trace_event_ignore_this_pid(trace_file))
260                 return NULL;
261 
262         local_save_flags(fbuffer->flags);
263         fbuffer->pc = preempt_count();
264         /*
265          * If CONFIG_PREEMPT is enabled, then the tracepoint itself disables
266          * preemption (adding one to the preempt_count). Since we are
267          * interested in the preempt_count at the time the tracepoint was
268          * hit, we need to subtract one to offset the increment.
269          */
270         if (IS_ENABLED(CONFIG_PREEMPT))
271                 fbuffer->pc--;
272         fbuffer->trace_file = trace_file;
273 
274         fbuffer->event =
275                 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
276                                                 event_call->event.type, len,
277                                                 fbuffer->flags, fbuffer->pc);
278         if (!fbuffer->event)
279                 return NULL;
280 
281         fbuffer->entry = ring_buffer_event_data(fbuffer->event);
282         return fbuffer->entry;
283 }
284 EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
285 
286 int trace_event_reg(struct trace_event_call *call,
287                     enum trace_reg type, void *data)
288 {
289         struct trace_event_file *file = data;
290 
291         WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
292         switch (type) {
293         case TRACE_REG_REGISTER:
294                 return tracepoint_probe_register(call->tp,
295                                                  call->class->probe,
296                                                  file);
297         case TRACE_REG_UNREGISTER:
298                 tracepoint_probe_unregister(call->tp,
299                                             call->class->probe,
300                                             file);
301                 return 0;
302 
303 #ifdef CONFIG_PERF_EVENTS
304         case TRACE_REG_PERF_REGISTER:
305                 return tracepoint_probe_register(call->tp,
306                                                  call->class->perf_probe,
307                                                  call);
308         case TRACE_REG_PERF_UNREGISTER:
309                 tracepoint_probe_unregister(call->tp,
310                                             call->class->perf_probe,
311                                             call);
312                 return 0;
313         case TRACE_REG_PERF_OPEN:
314         case TRACE_REG_PERF_CLOSE:
315         case TRACE_REG_PERF_ADD:
316         case TRACE_REG_PERF_DEL:
317                 return 0;
318 #endif
319         }
320         return 0;
321 }
322 EXPORT_SYMBOL_GPL(trace_event_reg);
323 
324 void trace_event_enable_cmd_record(bool enable)
325 {
326         struct trace_event_file *file;
327         struct trace_array *tr;
328 
329         mutex_lock(&event_mutex);
330         do_for_each_event_file(tr, file) {
331 
332                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
333                         continue;
334 
335                 if (enable) {
336                         tracing_start_cmdline_record();
337                         set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
338                 } else {
339                         tracing_stop_cmdline_record();
340                         clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
341                 }
342         } while_for_each_event_file();
343         mutex_unlock(&event_mutex);
344 }
345 
346 void trace_event_enable_tgid_record(bool enable)
347 {
348         struct trace_event_file *file;
349         struct trace_array *tr;
350 
351         mutex_lock(&event_mutex);
352         do_for_each_event_file(tr, file) {
353                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
354                         continue;
355 
356                 if (enable) {
357                         tracing_start_tgid_record();
358                         set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
359                 } else {
360                         tracing_stop_tgid_record();
361                         clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
362                                   &file->flags);
363                 }
364         } while_for_each_event_file();
365         mutex_unlock(&event_mutex);
366 }
367 
368 static int __ftrace_event_enable_disable(struct trace_event_file *file,
369                                          int enable, int soft_disable)
370 {
371         struct trace_event_call *call = file->event_call;
372         struct trace_array *tr = file->tr;
373         unsigned long file_flags = file->flags;
374         int ret = 0;
375         int disable;
376 
377         switch (enable) {
378         case 0:
379                 /*
380                  * When soft_disable is set and enable is cleared, the sm_ref
381                  * reference counter is decremented. If it reaches 0, we want
382                  * to clear the SOFT_DISABLED flag but leave the event in the
383                  * state that it was. That is, if the event was enabled and
384                  * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
385                  * is set we do not want the event to be enabled before we
386                  * clear the bit.
387                  *
388                  * When soft_disable is not set but the SOFT_MODE flag is,
389                  * we do nothing. Do not disable the tracepoint, otherwise
390                  * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
391                  */
392                 if (soft_disable) {
393                         if (atomic_dec_return(&file->sm_ref) > 0)
394                                 break;
395                         disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
396                         clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
397                 } else
398                         disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
399 
400                 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
401                         clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
402                         if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
403                                 tracing_stop_cmdline_record();
404                                 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
405                         }
406 
407                         if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
408                                 tracing_stop_tgid_record();
409                                 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
410                         }
411 
412                         call->class->reg(call, TRACE_REG_UNREGISTER, file);
413                 }
414                 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
415                 if (file->flags & EVENT_FILE_FL_SOFT_MODE)
416                         set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
417                 else
418                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
419                 break;
420         case 1:
421                 /*
422                  * When soft_disable is set and enable is set, we want to
423                  * register the tracepoint for the event, but leave the event
424                  * as is. That means, if the event was already enabled, we do
425                  * nothing (but set SOFT_MODE). If the event is disabled, we
426                  * set SOFT_DISABLED before enabling the event tracepoint, so
427                  * it still seems to be disabled.
428                  */
429                 if (!soft_disable)
430                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
431                 else {
432                         if (atomic_inc_return(&file->sm_ref) > 1)
433                                 break;
434                         set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
435                 }
436 
437                 if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
438                         bool cmd = false, tgid = false;
439 
440                         /* Keep the event disabled, when going to SOFT_MODE. */
441                         if (soft_disable)
442                                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
443 
444                         if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
445                                 cmd = true;
446                                 tracing_start_cmdline_record();
447                                 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
448                         }
449 
450                         if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
451                                 tgid = true;
452                                 tracing_start_tgid_record();
453                                 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
454                         }
455 
456                         ret = call->class->reg(call, TRACE_REG_REGISTER, file);
457                         if (ret) {
458                                 if (cmd)
459                                         tracing_stop_cmdline_record();
460                                 if (tgid)
461                                         tracing_stop_tgid_record();
462                                 pr_info("event trace: Could not enable event "
463                                         "%s\n", trace_event_name(call));
464                                 break;
465                         }
466                         set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
467 
468                         /* WAS_ENABLED gets set but never cleared. */
469                         set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
470                 }
471                 break;
472         }
473 
474         /* Enable or disable use of trace_buffered_event */
475         if ((file_flags & EVENT_FILE_FL_SOFT_DISABLED) !=
476             (file->flags & EVENT_FILE_FL_SOFT_DISABLED)) {
477                 if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
478                         trace_buffered_event_enable();
479                 else
480                         trace_buffered_event_disable();
481         }
482 
483         return ret;
484 }
485 
486 int trace_event_enable_disable(struct trace_event_file *file,
487                                int enable, int soft_disable)
488 {
489         return __ftrace_event_enable_disable(file, enable, soft_disable);
490 }
491 
492 static int ftrace_event_enable_disable(struct trace_event_file *file,
493                                        int enable)
494 {
495         return __ftrace_event_enable_disable(file, enable, 0);
496 }
497 
498 static void ftrace_clear_events(struct trace_array *tr)
499 {
500         struct trace_event_file *file;
501 
502         mutex_lock(&event_mutex);
503         list_for_each_entry(file, &tr->events, list) {
504                 ftrace_event_enable_disable(file, 0);
505         }
506         mutex_unlock(&event_mutex);
507 }
508 
509 static void
510 event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
511 {
512         struct trace_pid_list *pid_list;
513         struct trace_array *tr = data;
514 
515         pid_list = rcu_dereference_sched(tr->filtered_pids);
516         trace_filter_add_remove_task(pid_list, NULL, task);
517 }
518 
519 static void
520 event_filter_pid_sched_process_fork(void *data,
521                                     struct task_struct *self,
522                                     struct task_struct *task)
523 {
524         struct trace_pid_list *pid_list;
525         struct trace_array *tr = data;
526 
527         pid_list = rcu_dereference_sched(tr->filtered_pids);
528         trace_filter_add_remove_task(pid_list, self, task);
529 }
530 
531 void trace_event_follow_fork(struct trace_array *tr, bool enable)
532 {
533         if (enable) {
534                 register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
535                                                        tr, INT_MIN);
536                 register_trace_prio_sched_process_exit(event_filter_pid_sched_process_exit,
537                                                        tr, INT_MAX);
538         } else {
539                 unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
540                                                     tr);
541                 unregister_trace_sched_process_exit(event_filter_pid_sched_process_exit,
542                                                     tr);
543         }
544 }
545 
546 static void
547 event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
548                     struct task_struct *prev, struct task_struct *next)
549 {
550         struct trace_array *tr = data;
551         struct trace_pid_list *pid_list;
552 
553         pid_list = rcu_dereference_sched(tr->filtered_pids);
554 
555         this_cpu_write(tr->trace_buffer.data->ignore_pid,
556                        trace_ignore_this_task(pid_list, prev) &&
557                        trace_ignore_this_task(pid_list, next));
558 }
559 
560 static void
561 event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
562                     struct task_struct *prev, struct task_struct *next)
563 {
564         struct trace_array *tr = data;
565         struct trace_pid_list *pid_list;
566 
567         pid_list = rcu_dereference_sched(tr->filtered_pids);
568 
569         this_cpu_write(tr->trace_buffer.data->ignore_pid,
570                        trace_ignore_this_task(pid_list, next));
571 }
572 
573 static void
574 event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
575 {
576         struct trace_array *tr = data;
577         struct trace_pid_list *pid_list;
578 
579         /* Nothing to do if we are already tracing */
580         if (!this_cpu_read(tr->trace_buffer.data->ignore_pid))
581                 return;
582 
583         pid_list = rcu_dereference_sched(tr->filtered_pids);
584 
585         this_cpu_write(tr->trace_buffer.data->ignore_pid,
586                        trace_ignore_this_task(pid_list, task));
587 }
588 
589 static void
590 event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
591 {
592         struct trace_array *tr = data;
593         struct trace_pid_list *pid_list;
594 
595         /* Nothing to do if we are not tracing */
596         if (this_cpu_read(tr->trace_buffer.data->ignore_pid))
597                 return;
598 
599         pid_list = rcu_dereference_sched(tr->filtered_pids);
600 
601         /* Set tracing if current is enabled */
602         this_cpu_write(tr->trace_buffer.data->ignore_pid,
603                        trace_ignore_this_task(pid_list, current));
604 }
605 
606 static void __ftrace_clear_event_pids(struct trace_array *tr)
607 {
608         struct trace_pid_list *pid_list;
609         struct trace_event_file *file;
610         int cpu;
611 
612         pid_list = rcu_dereference_protected(tr->filtered_pids,
613                                              lockdep_is_held(&event_mutex));
614         if (!pid_list)
615                 return;
616 
617         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
618         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
619 
620         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
621         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
622 
623         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
624         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
625 
626         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
627         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
628 
629         list_for_each_entry(file, &tr->events, list) {
630                 clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
631         }
632 
633         for_each_possible_cpu(cpu)
634                 per_cpu_ptr(tr->trace_buffer.data, cpu)->ignore_pid = false;
635 
636         rcu_assign_pointer(tr->filtered_pids, NULL);
637 
638         /* Wait till all users are no longer using pid filtering */
639         synchronize_sched();
640 
641         trace_free_pid_list(pid_list);
642 }
643 
644 static void ftrace_clear_event_pids(struct trace_array *tr)
645 {
646         mutex_lock(&event_mutex);
647         __ftrace_clear_event_pids(tr);
648         mutex_unlock(&event_mutex);
649 }
650 
651 static void __put_system(struct event_subsystem *system)
652 {
653         struct event_filter *filter = system->filter;
654 
655         WARN_ON_ONCE(system_refcount(system) == 0);
656         if (system_refcount_dec(system))
657                 return;
658 
659         list_del(&system->list);
660 
661         if (filter) {
662                 kfree(filter->filter_string);
663                 kfree(filter);
664         }
665         kfree_const(system->name);
666         kfree(system);
667 }
668 
669 static void __get_system(struct event_subsystem *system)
670 {
671         WARN_ON_ONCE(system_refcount(system) == 0);
672         system_refcount_inc(system);
673 }
674 
675 static void __get_system_dir(struct trace_subsystem_dir *dir)
676 {
677         WARN_ON_ONCE(dir->ref_count == 0);
678         dir->ref_count++;
679         __get_system(dir->subsystem);
680 }
681 
682 static void __put_system_dir(struct trace_subsystem_dir *dir)
683 {
684         WARN_ON_ONCE(dir->ref_count == 0);
685         /* If the subsystem is about to be freed, the dir must be too */
686         WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
687 
688         __put_system(dir->subsystem);
689         if (!--dir->ref_count)
690                 kfree(dir);
691 }
692 
693 static void put_system(struct trace_subsystem_dir *dir)
694 {
695         mutex_lock(&event_mutex);
696         __put_system_dir(dir);
697         mutex_unlock(&event_mutex);
698 }
699 
700 static void remove_subsystem(struct trace_subsystem_dir *dir)
701 {
702         if (!dir)
703                 return;
704 
705         if (!--dir->nr_events) {
706                 tracefs_remove_recursive(dir->entry);
707                 list_del(&dir->list);
708                 __put_system_dir(dir);
709         }
710 }
711 
712 static void remove_event_file_dir(struct trace_event_file *file)
713 {
714         struct dentry *dir = file->dir;
715         struct dentry *child;
716 
717         if (dir) {
718                 spin_lock(&dir->d_lock);        /* probably unneeded */
719                 list_for_each_entry(child, &dir->d_subdirs, d_child) {
720                         if (d_really_is_positive(child))        /* probably unneeded */
721                                 d_inode(child)->i_private = NULL;
722                 }
723                 spin_unlock(&dir->d_lock);
724 
725                 tracefs_remove_recursive(dir);
726         }
727 
728         list_del(&file->list);
729         remove_subsystem(file->system);
730         free_event_filter(file->filter);
731         kmem_cache_free(file_cachep, file);
732 }
733 
734 /*
735  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
736  */
737 static int
738 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
739                               const char *sub, const char *event, int set)
740 {
741         struct trace_event_file *file;
742         struct trace_event_call *call;
743         const char *name;
744         int ret = -EINVAL;
745         int eret = 0;
746 
747         list_for_each_entry(file, &tr->events, list) {
748 
749                 call = file->event_call;
750                 name = trace_event_name(call);
751 
752                 if (!name || !call->class || !call->class->reg)
753                         continue;
754 
755                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
756                         continue;
757 
758                 if (match &&
759                     strcmp(match, name) != 0 &&
760                     strcmp(match, call->class->system) != 0)
761                         continue;
762 
763                 if (sub && strcmp(sub, call->class->system) != 0)
764                         continue;
765 
766                 if (event && strcmp(event, name) != 0)
767                         continue;
768 
769                 ret = ftrace_event_enable_disable(file, set);
770 
771                 /*
772                  * Save the first error and return that. Some events
773                  * may still have been enabled, but let the user
774                  * know that something went wrong.
775                  */
776                 if (ret && !eret)
777                         eret = ret;
778 
779                 ret = eret;
780         }
781 
782         return ret;
783 }
784 
785 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
786                                   const char *sub, const char *event, int set)
787 {
788         int ret;
789 
790         mutex_lock(&event_mutex);
791         ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
792         mutex_unlock(&event_mutex);
793 
794         return ret;
795 }
796 
797 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
798 {
799         char *event = NULL, *sub = NULL, *match;
800         int ret;
801 
802         /*
803          * The buf format can be <subsystem>:<event-name>
804          *  *:<event-name> means any event by that name.
805          *  :<event-name> is the same.
806          *
807          *  <subsystem>:* means all events in that subsystem
808          *  <subsystem>: means the same.
809          *
810          *  <name> (no ':') means all events in a subsystem with
811          *  the name <name> or any event that matches <name>
812          */
813 
814         match = strsep(&buf, ":");
815         if (buf) {
816                 sub = match;
817                 event = buf;
818                 match = NULL;
819 
820                 if (!strlen(sub) || strcmp(sub, "*") == 0)
821                         sub = NULL;
822                 if (!strlen(event) || strcmp(event, "*") == 0)
823                         event = NULL;
824         }
825 
826         ret = __ftrace_set_clr_event(tr, match, sub, event, set);
827 
828         /* Put back the colon to allow this to be called again */
829         if (buf)
830                 *(buf - 1) = ':';
831 
832         return ret;
833 }
834 
835 /**
836  * trace_set_clr_event - enable or disable an event
837  * @system: system name to match (NULL for any system)
838  * @event: event name to match (NULL for all events, within system)
839  * @set: 1 to enable, 0 to disable
840  *
841  * This is a way for other parts of the kernel to enable or disable
842  * event recording.
843  *
844  * Returns 0 on success, -EINVAL if the parameters do not match any
845  * registered events.
846  */
847 int trace_set_clr_event(const char *system, const char *event, int set)
848 {
849         struct trace_array *tr = top_trace_array();
850 
851         if (!tr)
852                 return -ENODEV;
853 
854         return __ftrace_set_clr_event(tr, NULL, system, event, set);
855 }
856 EXPORT_SYMBOL_GPL(trace_set_clr_event);
857 
858 /* 128 should be much more than enough */
859 #define EVENT_BUF_SIZE          127
860 
861 static ssize_t
862 ftrace_event_write(struct file *file, const char __user *ubuf,
863                    size_t cnt, loff_t *ppos)
864 {
865         struct trace_parser parser;
866         struct seq_file *m = file->private_data;
867         struct trace_array *tr = m->private;
868         ssize_t read, ret;
869 
870         if (!cnt)
871                 return 0;
872 
873         ret = tracing_update_buffers();
874         if (ret < 0)
875                 return ret;
876 
877         if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
878                 return -ENOMEM;
879 
880         read = trace_get_user(&parser, ubuf, cnt, ppos);
881 
882         if (read >= 0 && trace_parser_loaded((&parser))) {
883                 int set = 1;
884 
885                 if (*parser.buffer == '!')
886                         set = 0;
887 
888                 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
889                 if (ret)
890                         goto out_put;
891         }
892 
893         ret = read;
894 
895  out_put:
896         trace_parser_put(&parser);
897 
898         return ret;
899 }
900 
901 static void *
902 t_next(struct seq_file *m, void *v, loff_t *pos)
903 {
904         struct trace_event_file *file = v;
905         struct trace_event_call *call;
906         struct trace_array *tr = m->private;
907 
908         (*pos)++;
909 
910         list_for_each_entry_continue(file, &tr->events, list) {
911                 call = file->event_call;
912                 /*
913                  * The ftrace subsystem is for showing formats only.
914                  * They can not be enabled or disabled via the event files.
915                  */
916                 if (call->class && call->class->reg &&
917                     !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
918                         return file;
919         }
920 
921         return NULL;
922 }
923 
924 static void *t_start(struct seq_file *m, loff_t *pos)
925 {
926         struct trace_event_file *file;
927         struct trace_array *tr = m->private;
928         loff_t l;
929 
930         mutex_lock(&event_mutex);
931 
932         file = list_entry(&tr->events, struct trace_event_file, list);
933         for (l = 0; l <= *pos; ) {
934                 file = t_next(m, file, &l);
935                 if (!file)
936                         break;
937         }
938         return file;
939 }
940 
941 static void *
942 s_next(struct seq_file *m, void *v, loff_t *pos)
943 {
944         struct trace_event_file *file = v;
945         struct trace_array *tr = m->private;
946 
947         (*pos)++;
948 
949         list_for_each_entry_continue(file, &tr->events, list) {
950                 if (file->flags & EVENT_FILE_FL_ENABLED)
951                         return file;
952         }
953 
954         return NULL;
955 }
956 
957 static void *s_start(struct seq_file *m, loff_t *pos)
958 {
959         struct trace_event_file *file;
960         struct trace_array *tr = m->private;
961         loff_t l;
962 
963         mutex_lock(&event_mutex);
964 
965         file = list_entry(&tr->events, struct trace_event_file, list);
966         for (l = 0; l <= *pos; ) {
967                 file = s_next(m, file, &l);
968                 if (!file)
969                         break;
970         }
971         return file;
972 }
973 
974 static int t_show(struct seq_file *m, void *v)
975 {
976         struct trace_event_file *file = v;
977         struct trace_event_call *call = file->event_call;
978 
979         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
980                 seq_printf(m, "%s:", call->class->system);
981         seq_printf(m, "%s\n", trace_event_name(call));
982 
983         return 0;
984 }
985 
986 static void t_stop(struct seq_file *m, void *p)
987 {
988         mutex_unlock(&event_mutex);
989 }
990 
991 static void *
992 p_next(struct seq_file *m, void *v, loff_t *pos)
993 {
994         struct trace_array *tr = m->private;
995         struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids);
996 
997         return trace_pid_next(pid_list, v, pos);
998 }
999 
1000 static void *p_start(struct seq_file *m, loff_t *pos)
1001         __acquires(RCU)
1002 {
1003         struct trace_pid_list *pid_list;
1004         struct trace_array *tr = m->private;
1005 
1006         /*
1007          * Grab the mutex, to keep calls to p_next() having the same
1008          * tr->filtered_pids as p_start() has.
1009          * If we just passed the tr->filtered_pids around, then RCU would
1010          * have been enough, but doing that makes things more complex.
1011          */
1012         mutex_lock(&event_mutex);
1013         rcu_read_lock_sched();
1014 
1015         pid_list = rcu_dereference_sched(tr->filtered_pids);
1016 
1017         if (!pid_list)
1018                 return NULL;
1019 
1020         return trace_pid_start(pid_list, pos);
1021 }
1022 
1023 static void p_stop(struct seq_file *m, void *p)
1024         __releases(RCU)
1025 {
1026         rcu_read_unlock_sched();
1027         mutex_unlock(&event_mutex);
1028 }
1029 
1030 static ssize_t
1031 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1032                   loff_t *ppos)
1033 {
1034         struct trace_event_file *file;
1035         unsigned long flags;
1036         char buf[4] = "";
1037 
1038         mutex_lock(&event_mutex);
1039         file = event_file_data(filp);
1040         if (likely(file))
1041                 flags = file->flags;
1042         mutex_unlock(&event_mutex);
1043 
1044         if (!file)
1045                 return -ENODEV;
1046 
1047         if (flags & EVENT_FILE_FL_ENABLED &&
1048             !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1049                 strcpy(buf, "1");
1050 
1051         if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1052             flags & EVENT_FILE_FL_SOFT_MODE)
1053                 strcat(buf, "*");
1054 
1055         strcat(buf, "\n");
1056 
1057         return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1058 }
1059 
1060 static ssize_t
1061 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1062                    loff_t *ppos)
1063 {
1064         struct trace_event_file *file;
1065         unsigned long val;
1066         int ret;
1067 
1068         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1069         if (ret)
1070                 return ret;
1071 
1072         ret = tracing_update_buffers();
1073         if (ret < 0)
1074                 return ret;
1075 
1076         switch (val) {
1077         case 0:
1078         case 1:
1079                 ret = -ENODEV;
1080                 mutex_lock(&event_mutex);
1081                 file = event_file_data(filp);
1082                 if (likely(file))
1083                         ret = ftrace_event_enable_disable(file, val);
1084                 mutex_unlock(&event_mutex);
1085                 break;
1086 
1087         default:
1088                 return -EINVAL;
1089         }
1090 
1091         *ppos += cnt;
1092 
1093         return ret ? ret : cnt;
1094 }
1095 
1096 static ssize_t
1097 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1098                    loff_t *ppos)
1099 {
1100         const char set_to_char[4] = { '?', '', '1', 'X' };
1101         struct trace_subsystem_dir *dir = filp->private_data;
1102         struct event_subsystem *system = dir->subsystem;
1103         struct trace_event_call *call;
1104         struct trace_event_file *file;
1105         struct trace_array *tr = dir->tr;
1106         char buf[2];
1107         int set = 0;
1108         int ret;
1109 
1110         mutex_lock(&event_mutex);
1111         list_for_each_entry(file, &tr->events, list) {
1112                 call = file->event_call;
1113                 if (!trace_event_name(call) || !call->class || !call->class->reg)
1114                         continue;
1115 
1116                 if (system && strcmp(call->class->system, system->name) != 0)
1117                         continue;
1118 
1119                 /*
1120                  * We need to find out if all the events are set
1121                  * or if all events or cleared, or if we have
1122                  * a mixture.
1123                  */
1124                 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1125 
1126                 /*
1127                  * If we have a mixture, no need to look further.
1128                  */
1129                 if (set == 3)
1130                         break;
1131         }
1132         mutex_unlock(&event_mutex);
1133 
1134         buf[0] = set_to_char[set];
1135         buf[1] = '\n';
1136 
1137         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1138 
1139         return ret;
1140 }
1141 
1142 static ssize_t
1143 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1144                     loff_t *ppos)
1145 {
1146         struct trace_subsystem_dir *dir = filp->private_data;
1147         struct event_subsystem *system = dir->subsystem;
1148         const char *name = NULL;
1149         unsigned long val;
1150         ssize_t ret;
1151 
1152         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1153         if (ret)
1154                 return ret;
1155 
1156         ret = tracing_update_buffers();
1157         if (ret < 0)
1158                 return ret;
1159 
1160         if (val != 0 && val != 1)
1161                 return -EINVAL;
1162 
1163         /*
1164          * Opening of "enable" adds a ref count to system,
1165          * so the name is safe to use.
1166          */
1167         if (system)
1168                 name = system->name;
1169 
1170         ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1171         if (ret)
1172                 goto out;
1173 
1174         ret = cnt;
1175 
1176 out:
1177         *ppos += cnt;
1178 
1179         return ret;
1180 }
1181 
1182 enum {
1183         FORMAT_HEADER           = 1,
1184         FORMAT_FIELD_SEPERATOR  = 2,
1185         FORMAT_PRINTFMT         = 3,
1186 };
1187 
1188 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1189 {
1190         struct trace_event_call *call = event_file_data(m->private);
1191         struct list_head *common_head = &ftrace_common_fields;
1192         struct list_head *head = trace_get_fields(call);
1193         struct list_head *node = v;
1194 
1195         (*pos)++;
1196 
1197         switch ((unsigned long)v) {
1198         case FORMAT_HEADER:
1199                 node = common_head;
1200                 break;
1201 
1202         case FORMAT_FIELD_SEPERATOR:
1203                 node = head;
1204                 break;
1205 
1206         case FORMAT_PRINTFMT:
1207                 /* all done */
1208                 return NULL;
1209         }
1210 
1211         node = node->prev;
1212         if (node == common_head)
1213                 return (void *)FORMAT_FIELD_SEPERATOR;
1214         else if (node == head)
1215                 return (void *)FORMAT_PRINTFMT;
1216         else
1217                 return node;
1218 }
1219 
1220 static int f_show(struct seq_file *m, void *v)
1221 {
1222         struct trace_event_call *call = event_file_data(m->private);
1223         struct ftrace_event_field *field;
1224         const char *array_descriptor;
1225 
1226         switch ((unsigned long)v) {
1227         case FORMAT_HEADER:
1228                 seq_printf(m, "name: %s\n", trace_event_name(call));
1229                 seq_printf(m, "ID: %d\n", call->event.type);
1230                 seq_puts(m, "format:\n");
1231                 return 0;
1232 
1233         case FORMAT_FIELD_SEPERATOR:
1234                 seq_putc(m, '\n');
1235                 return 0;
1236 
1237         case FORMAT_PRINTFMT:
1238                 seq_printf(m, "\nprint fmt: %s\n",
1239                            call->print_fmt);
1240                 return 0;
1241         }
1242 
1243         field = list_entry(v, struct ftrace_event_field, link);
1244         /*
1245          * Smartly shows the array type(except dynamic array).
1246          * Normal:
1247          *      field:TYPE VAR
1248          * If TYPE := TYPE[LEN], it is shown:
1249          *      field:TYPE VAR[LEN]
1250          */
1251         array_descriptor = strchr(field->type, '[');
1252 
1253         if (!strncmp(field->type, "__data_loc", 10))
1254                 array_descriptor = NULL;
1255 
1256         if (!array_descriptor)
1257                 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1258                            field->type, field->name, field->offset,
1259                            field->size, !!field->is_signed);
1260         else
1261                 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1262                            (int)(array_descriptor - field->type),
1263                            field->type, field->name,
1264                            array_descriptor, field->offset,
1265                            field->size, !!field->is_signed);
1266 
1267         return 0;
1268 }
1269 
1270 static void *f_start(struct seq_file *m, loff_t *pos)
1271 {
1272         void *p = (void *)FORMAT_HEADER;
1273         loff_t l = 0;
1274 
1275         /* ->stop() is called even if ->start() fails */
1276         mutex_lock(&event_mutex);
1277         if (!event_file_data(m->private))
1278                 return ERR_PTR(-ENODEV);
1279 
1280         while (l < *pos && p)
1281                 p = f_next(m, p, &l);
1282 
1283         return p;
1284 }
1285 
1286 static void f_stop(struct seq_file *m, void *p)
1287 {
1288         mutex_unlock(&event_mutex);
1289 }
1290 
1291 static const struct seq_operations trace_format_seq_ops = {
1292         .start          = f_start,
1293         .next           = f_next,
1294         .stop           = f_stop,
1295         .show           = f_show,
1296 };
1297 
1298 static int trace_format_open(struct inode *inode, struct file *file)
1299 {
1300         struct seq_file *m;
1301         int ret;
1302 
1303         ret = seq_open(file, &trace_format_seq_ops);
1304         if (ret < 0)
1305                 return ret;
1306 
1307         m = file->private_data;
1308         m->private = file;
1309 
1310         return 0;
1311 }
1312 
1313 static ssize_t
1314 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1315 {
1316         int id = (long)event_file_data(filp);
1317         char buf[32];
1318         int len;
1319 
1320         if (*ppos)
1321                 return 0;
1322 
1323         if (unlikely(!id))
1324                 return -ENODEV;
1325 
1326         len = sprintf(buf, "%d\n", id);
1327 
1328         return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1329 }
1330 
1331 static ssize_t
1332 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1333                   loff_t *ppos)
1334 {
1335         struct trace_event_file *file;
1336         struct trace_seq *s;
1337         int r = -ENODEV;
1338 
1339         if (*ppos)
1340                 return 0;
1341 
1342         s = kmalloc(sizeof(*s), GFP_KERNEL);
1343 
1344         if (!s)
1345                 return -ENOMEM;
1346 
1347         trace_seq_init(s);
1348 
1349         mutex_lock(&event_mutex);
1350         file = event_file_data(filp);
1351         if (file)
1352                 print_event_filter(file, s);
1353         mutex_unlock(&event_mutex);
1354 
1355         if (file)
1356                 r = simple_read_from_buffer(ubuf, cnt, ppos,
1357                                             s->buffer, trace_seq_used(s));
1358 
1359         kfree(s);
1360 
1361         return r;
1362 }
1363 
1364 static ssize_t
1365 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1366                    loff_t *ppos)
1367 {
1368         struct trace_event_file *file;
1369         char *buf;
1370         int err = -ENODEV;
1371 
1372         if (cnt >= PAGE_SIZE)
1373                 return -EINVAL;
1374 
1375         buf = memdup_user_nul(ubuf, cnt);
1376         if (IS_ERR(buf))
1377                 return PTR_ERR(buf);
1378 
1379         mutex_lock(&event_mutex);
1380         file = event_file_data(filp);
1381         if (file)
1382                 err = apply_event_filter(file, buf);
1383         mutex_unlock(&event_mutex);
1384 
1385         kfree(buf);
1386         if (err < 0)
1387                 return err;
1388 
1389         *ppos += cnt;
1390 
1391         return cnt;
1392 }
1393 
1394 static LIST_HEAD(event_subsystems);
1395 
1396 static int subsystem_open(struct inode *inode, struct file *filp)
1397 {
1398         struct event_subsystem *system = NULL;
1399         struct trace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1400         struct trace_array *tr;
1401         int ret;
1402 
1403         if (tracing_is_disabled())
1404                 return -ENODEV;
1405 
1406         /* Make sure the system still exists */
1407         mutex_lock(&event_mutex);
1408         mutex_lock(&trace_types_lock);
1409         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1410                 list_for_each_entry(dir, &tr->systems, list) {
1411                         if (dir == inode->i_private) {
1412                                 /* Don't open systems with no events */
1413                                 if (dir->nr_events) {
1414                                         __get_system_dir(dir);
1415                                         system = dir->subsystem;
1416                                 }
1417                                 goto exit_loop;
1418                         }
1419                 }
1420         }
1421  exit_loop:
1422         mutex_unlock(&trace_types_lock);
1423         mutex_unlock(&event_mutex);
1424 
1425         if (!system)
1426                 return -ENODEV;
1427 
1428         /* Some versions of gcc think dir can be uninitialized here */
1429         WARN_ON(!dir);
1430 
1431         /* Still need to increment the ref count of the system */
1432         if (trace_array_get(tr) < 0) {
1433                 put_system(dir);
1434                 return -ENODEV;
1435         }
1436 
1437         ret = tracing_open_generic(inode, filp);
1438         if (ret < 0) {
1439                 trace_array_put(tr);
1440                 put_system(dir);
1441         }
1442 
1443         return ret;
1444 }
1445 
1446 static int system_tr_open(struct inode *inode, struct file *filp)
1447 {
1448         struct trace_subsystem_dir *dir;
1449         struct trace_array *tr = inode->i_private;
1450         int ret;
1451 
1452         if (tracing_is_disabled())
1453                 return -ENODEV;
1454 
1455         if (trace_array_get(tr) < 0)
1456                 return -ENODEV;
1457 
1458         /* Make a temporary dir that has no system but points to tr */
1459         dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1460         if (!dir) {
1461                 trace_array_put(tr);
1462                 return -ENOMEM;
1463         }
1464 
1465         dir->tr = tr;
1466 
1467         ret = tracing_open_generic(inode, filp);
1468         if (ret < 0) {
1469                 trace_array_put(tr);
1470                 kfree(dir);
1471                 return ret;
1472         }
1473 
1474         filp->private_data = dir;
1475 
1476         return 0;
1477 }
1478 
1479 static int subsystem_release(struct inode *inode, struct file *file)
1480 {
1481         struct trace_subsystem_dir *dir = file->private_data;
1482 
1483         trace_array_put(dir->tr);
1484 
1485         /*
1486          * If dir->subsystem is NULL, then this is a temporary
1487          * descriptor that was made for a trace_array to enable
1488          * all subsystems.
1489          */
1490         if (dir->subsystem)
1491                 put_system(dir);
1492         else
1493                 kfree(dir);
1494 
1495         return 0;
1496 }
1497 
1498 static ssize_t
1499 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1500                       loff_t *ppos)
1501 {
1502         struct trace_subsystem_dir *dir = filp->private_data;
1503         struct event_subsystem *system = dir->subsystem;
1504         struct trace_seq *s;
1505         int r;
1506 
1507         if (*ppos)
1508                 return 0;
1509 
1510         s = kmalloc(sizeof(*s), GFP_KERNEL);
1511         if (!s)
1512                 return -ENOMEM;
1513 
1514         trace_seq_init(s);
1515 
1516         print_subsystem_event_filter(system, s);
1517         r = simple_read_from_buffer(ubuf, cnt, ppos,
1518                                     s->buffer, trace_seq_used(s));
1519 
1520         kfree(s);
1521 
1522         return r;
1523 }
1524 
1525 static ssize_t
1526 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1527                        loff_t *ppos)
1528 {
1529         struct trace_subsystem_dir *dir = filp->private_data;
1530         char *buf;
1531         int err;
1532 
1533         if (cnt >= PAGE_SIZE)
1534                 return -EINVAL;
1535 
1536         buf = memdup_user_nul(ubuf, cnt);
1537         if (IS_ERR(buf))
1538                 return PTR_ERR(buf);
1539 
1540         err = apply_subsystem_event_filter(dir, buf);
1541         kfree(buf);
1542         if (err < 0)
1543                 return err;
1544 
1545         *ppos += cnt;
1546 
1547         return cnt;
1548 }
1549 
1550 static ssize_t
1551 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1552 {
1553         int (*func)(struct trace_seq *s) = filp->private_data;
1554         struct trace_seq *s;
1555         int r;
1556 
1557         if (*ppos)
1558                 return 0;
1559 
1560         s = kmalloc(sizeof(*s), GFP_KERNEL);
1561         if (!s)
1562                 return -ENOMEM;
1563 
1564         trace_seq_init(s);
1565 
1566         func(s);
1567         r = simple_read_from_buffer(ubuf, cnt, ppos,
1568                                     s->buffer, trace_seq_used(s));
1569 
1570         kfree(s);
1571 
1572         return r;
1573 }
1574 
1575 static void ignore_task_cpu(void *data)
1576 {
1577         struct trace_array *tr = data;
1578         struct trace_pid_list *pid_list;
1579 
1580         /*
1581          * This function is called by on_each_cpu() while the
1582          * event_mutex is held.
1583          */
1584         pid_list = rcu_dereference_protected(tr->filtered_pids,
1585                                              mutex_is_locked(&event_mutex));
1586 
1587         this_cpu_write(tr->trace_buffer.data->ignore_pid,
1588                        trace_ignore_this_task(pid_list, current));
1589 }
1590 
1591 static ssize_t
1592 ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
1593                        size_t cnt, loff_t *ppos)
1594 {
1595         struct seq_file *m = filp->private_data;
1596         struct trace_array *tr = m->private;
1597         struct trace_pid_list *filtered_pids = NULL;
1598         struct trace_pid_list *pid_list;
1599         struct trace_event_file *file;
1600         ssize_t ret;
1601 
1602         if (!cnt)
1603                 return 0;
1604 
1605         ret = tracing_update_buffers();
1606         if (ret < 0)
1607                 return ret;
1608 
1609         mutex_lock(&event_mutex);
1610 
1611         filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1612                                              lockdep_is_held(&event_mutex));
1613 
1614         ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
1615         if (ret < 0)
1616                 goto out;
1617 
1618         rcu_assign_pointer(tr->filtered_pids, pid_list);
1619 
1620         list_for_each_entry(file, &tr->events, list) {
1621                 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
1622         }
1623 
1624         if (filtered_pids) {
1625                 synchronize_sched();
1626                 trace_free_pid_list(filtered_pids);
1627         } else if (pid_list) {
1628                 /*
1629                  * Register a probe that is called before all other probes
1630                  * to set ignore_pid if next or prev do not match.
1631                  * Register a probe this is called after all other probes
1632                  * to only keep ignore_pid set if next pid matches.
1633                  */
1634                 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1635                                                  tr, INT_MAX);
1636                 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1637                                                  tr, 0);
1638 
1639                 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1640                                                  tr, INT_MAX);
1641                 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1642                                                  tr, 0);
1643 
1644                 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1645                                                      tr, INT_MAX);
1646                 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1647                                                      tr, 0);
1648 
1649                 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1650                                                  tr, INT_MAX);
1651                 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1652                                                  tr, 0);
1653         }
1654 
1655         /*
1656          * Ignoring of pids is done at task switch. But we have to
1657          * check for those tasks that are currently running.
1658          * Always do this in case a pid was appended or removed.
1659          */
1660         on_each_cpu(ignore_task_cpu, tr, 1);
1661 
1662  out:
1663         mutex_unlock(&event_mutex);
1664 
1665         if (ret > 0)
1666                 *ppos += ret;
1667 
1668         return ret;
1669 }
1670 
1671 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1672 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1673 static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
1674 static int ftrace_event_release(struct inode *inode, struct file *file);
1675 
1676 static const struct seq_operations show_event_seq_ops = {
1677         .start = t_start,
1678         .next = t_next,
1679         .show = t_show,
1680         .stop = t_stop,
1681 };
1682 
1683 static const struct seq_operations show_set_event_seq_ops = {
1684         .start = s_start,
1685         .next = s_next,
1686         .show = t_show,
1687         .stop = t_stop,
1688 };
1689 
1690 static const struct seq_operations show_set_pid_seq_ops = {
1691         .start = p_start,
1692         .next = p_next,
1693         .show = trace_pid_show,
1694         .stop = p_stop,
1695 };
1696 
1697 static const struct file_operations ftrace_avail_fops = {
1698         .open = ftrace_event_avail_open,
1699         .read = seq_read,
1700         .llseek = seq_lseek,
1701         .release = seq_release,
1702 };
1703 
1704 static const struct file_operations ftrace_set_event_fops = {
1705         .open = ftrace_event_set_open,
1706         .read = seq_read,
1707         .write = ftrace_event_write,
1708         .llseek = seq_lseek,
1709         .release = ftrace_event_release,
1710 };
1711 
1712 static const struct file_operations ftrace_set_event_pid_fops = {
1713         .open = ftrace_event_set_pid_open,
1714         .read = seq_read,
1715         .write = ftrace_event_pid_write,
1716         .llseek = seq_lseek,
1717         .release = ftrace_event_release,
1718 };
1719 
1720 static const struct file_operations ftrace_enable_fops = {
1721         .open = tracing_open_generic,
1722         .read = event_enable_read,
1723         .write = event_enable_write,
1724         .llseek = default_llseek,
1725 };
1726 
1727 static const struct file_operations ftrace_event_format_fops = {
1728         .open = trace_format_open,
1729         .read = seq_read,
1730         .llseek = seq_lseek,
1731         .release = seq_release,
1732 };
1733 
1734 static const struct file_operations ftrace_event_id_fops = {
1735         .read = event_id_read,
1736         .llseek = default_llseek,
1737 };
1738 
1739 static const struct file_operations ftrace_event_filter_fops = {
1740         .open = tracing_open_generic,
1741         .read = event_filter_read,
1742         .write = event_filter_write,
1743         .llseek = default_llseek,
1744 };
1745 
1746 static const struct file_operations ftrace_subsystem_filter_fops = {
1747         .open = subsystem_open,
1748         .read = subsystem_filter_read,
1749         .write = subsystem_filter_write,
1750         .llseek = default_llseek,
1751         .release = subsystem_release,
1752 };
1753 
1754 static const struct file_operations ftrace_system_enable_fops = {
1755         .open = subsystem_open,
1756         .read = system_enable_read,
1757         .write = system_enable_write,
1758         .llseek = default_llseek,
1759         .release = subsystem_release,
1760 };
1761 
1762 static const struct file_operations ftrace_tr_enable_fops = {
1763         .open = system_tr_open,
1764         .read = system_enable_read,
1765         .write = system_enable_write,
1766         .llseek = default_llseek,
1767         .release = subsystem_release,
1768 };
1769 
1770 static const struct file_operations ftrace_show_header_fops = {
1771         .open = tracing_open_generic,
1772         .read = show_header,
1773         .llseek = default_llseek,
1774 };
1775 
1776 static int
1777 ftrace_event_open(struct inode *inode, struct file *file,
1778                   const struct seq_operations *seq_ops)
1779 {
1780         struct seq_file *m;
1781         int ret;
1782 
1783         ret = seq_open(file, seq_ops);
1784         if (ret < 0)
1785                 return ret;
1786         m = file->private_data;
1787         /* copy tr over to seq ops */
1788         m->private = inode->i_private;
1789 
1790         return ret;
1791 }
1792 
1793 static int ftrace_event_release(struct inode *inode, struct file *file)
1794 {
1795         struct trace_array *tr = inode->i_private;
1796 
1797         trace_array_put(tr);
1798 
1799         return seq_release(inode, file);
1800 }
1801 
1802 static int
1803 ftrace_event_avail_open(struct inode *inode, struct file *file)
1804 {
1805         const struct seq_operations *seq_ops = &show_event_seq_ops;
1806 
1807         return ftrace_event_open(inode, file, seq_ops);
1808 }
1809 
1810 static int
1811 ftrace_event_set_open(struct inode *inode, struct file *file)
1812 {
1813         const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1814         struct trace_array *tr = inode->i_private;
1815         int ret;
1816 
1817         if (trace_array_get(tr) < 0)
1818                 return -ENODEV;
1819 
1820         if ((file->f_mode & FMODE_WRITE) &&
1821             (file->f_flags & O_TRUNC))
1822                 ftrace_clear_events(tr);
1823 
1824         ret = ftrace_event_open(inode, file, seq_ops);
1825         if (ret < 0)
1826                 trace_array_put(tr);
1827         return ret;
1828 }
1829 
1830 static int
1831 ftrace_event_set_pid_open(struct inode *inode, struct file *file)
1832 {
1833         const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
1834         struct trace_array *tr = inode->i_private;
1835         int ret;
1836 
1837         if (trace_array_get(tr) < 0)
1838                 return -ENODEV;
1839 
1840         if ((file->f_mode & FMODE_WRITE) &&
1841             (file->f_flags & O_TRUNC))
1842                 ftrace_clear_event_pids(tr);
1843 
1844         ret = ftrace_event_open(inode, file, seq_ops);
1845         if (ret < 0)
1846                 trace_array_put(tr);
1847         return ret;
1848 }
1849 
1850 static struct event_subsystem *
1851 create_new_subsystem(const char *name)
1852 {
1853         struct event_subsystem *system;
1854 
1855         /* need to create new entry */
1856         system = kmalloc(sizeof(*system), GFP_KERNEL);
1857         if (!system)
1858                 return NULL;
1859 
1860         system->ref_count = 1;
1861 
1862         /* Only allocate if dynamic (kprobes and modules) */
1863         system->name = kstrdup_const(name, GFP_KERNEL);
1864         if (!system->name)
1865                 goto out_free;
1866 
1867         system->filter = NULL;
1868 
1869         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1870         if (!system->filter)
1871                 goto out_free;
1872 
1873         list_add(&system->list, &event_subsystems);
1874 
1875         return system;
1876 
1877  out_free:
1878         kfree_const(system->name);
1879         kfree(system);
1880         return NULL;
1881 }
1882 
1883 static struct dentry *
1884 event_subsystem_dir(struct trace_array *tr, const char *name,
1885                     struct trace_event_file *file, struct dentry *parent)
1886 {
1887         struct trace_subsystem_dir *dir;
1888         struct event_subsystem *system;
1889         struct dentry *entry;
1890 
1891         /* First see if we did not already create this dir */
1892         list_for_each_entry(dir, &tr->systems, list) {
1893                 system = dir->subsystem;
1894                 if (strcmp(system->name, name) == 0) {
1895                         dir->nr_events++;
1896                         file->system = dir;
1897                         return dir->entry;
1898                 }
1899         }
1900 
1901         /* Now see if the system itself exists. */
1902         list_for_each_entry(system, &event_subsystems, list) {
1903                 if (strcmp(system->name, name) == 0)
1904                         break;
1905         }
1906         /* Reset system variable when not found */
1907         if (&system->list == &event_subsystems)
1908                 system = NULL;
1909 
1910         dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1911         if (!dir)
1912                 goto out_fail;
1913 
1914         if (!system) {
1915                 system = create_new_subsystem(name);
1916                 if (!system)
1917                         goto out_free;
1918         } else
1919                 __get_system(system);
1920 
1921         dir->entry = tracefs_create_dir(name, parent);
1922         if (!dir->entry) {
1923                 pr_warn("Failed to create system directory %s\n", name);
1924                 __put_system(system);
1925                 goto out_free;
1926         }
1927 
1928         dir->tr = tr;
1929         dir->ref_count = 1;
1930         dir->nr_events = 1;
1931         dir->subsystem = system;
1932         file->system = dir;
1933 
1934         entry = tracefs_create_file("filter", 0644, dir->entry, dir,
1935                                     &ftrace_subsystem_filter_fops);
1936         if (!entry) {
1937                 kfree(system->filter);
1938                 system->filter = NULL;
1939                 pr_warn("Could not create tracefs '%s/filter' entry\n", name);
1940         }
1941 
1942         trace_create_file("enable", 0644, dir->entry, dir,
1943                           &ftrace_system_enable_fops);
1944 
1945         list_add(&dir->list, &tr->systems);
1946 
1947         return dir->entry;
1948 
1949  out_free:
1950         kfree(dir);
1951  out_fail:
1952         /* Only print this message if failed on memory allocation */
1953         if (!dir || !system)
1954                 pr_warn("No memory to create event subsystem %s\n", name);
1955         return NULL;
1956 }
1957 
1958 static int
1959 event_create_dir(struct dentry *parent, struct trace_event_file *file)
1960 {
1961         struct trace_event_call *call = file->event_call;
1962         struct trace_array *tr = file->tr;
1963         struct list_head *head;
1964         struct dentry *d_events;
1965         const char *name;
1966         int ret;
1967 
1968         /*
1969          * If the trace point header did not define TRACE_SYSTEM
1970          * then the system would be called "TRACE_SYSTEM".
1971          */
1972         if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1973                 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1974                 if (!d_events)
1975                         return -ENOMEM;
1976         } else
1977                 d_events = parent;
1978 
1979         name = trace_event_name(call);
1980         file->dir = tracefs_create_dir(name, d_events);
1981         if (!file->dir) {
1982                 pr_warn("Could not create tracefs '%s' directory\n", name);
1983                 return -1;
1984         }
1985 
1986         if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1987                 trace_create_file("enable", 0644, file->dir, file,
1988                                   &ftrace_enable_fops);
1989 
1990 #ifdef CONFIG_PERF_EVENTS
1991         if (call->event.type && call->class->reg)
1992                 trace_create_file("id", 0444, file->dir,
1993                                   (void *)(long)call->event.type,
1994                                   &ftrace_event_id_fops);
1995 #endif
1996 
1997         /*
1998          * Other events may have the same class. Only update
1999          * the fields if they are not already defined.
2000          */
2001         head = trace_get_fields(call);
2002         if (list_empty(head)) {
2003                 ret = call->class->define_fields(call);
2004                 if (ret < 0) {
2005                         pr_warn("Could not initialize trace point events/%s\n",
2006                                 name);
2007                         return -1;
2008                 }
2009         }
2010         trace_create_file("filter", 0644, file->dir, file,
2011                           &ftrace_event_filter_fops);
2012 
2013         /*
2014          * Only event directories that can be enabled should have
2015          * triggers.
2016          */
2017         if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
2018                 trace_create_file("trigger", 0644, file->dir, file,
2019                                   &event_trigger_fops);
2020 
2021 #ifdef CONFIG_HIST_TRIGGERS
2022         trace_create_file("hist", 0444, file->dir, file,
2023                           &event_hist_fops);
2024 #endif
2025         trace_create_file("format", 0444, file->dir, call,
2026                           &ftrace_event_format_fops);
2027 
2028         return 0;
2029 }
2030 
2031 static void remove_event_from_tracers(struct trace_event_call *call)
2032 {
2033         struct trace_event_file *file;
2034         struct trace_array *tr;
2035 
2036         do_for_each_event_file_safe(tr, file) {
2037                 if (file->event_call != call)
2038                         continue;
2039 
2040                 remove_event_file_dir(file);
2041                 /*
2042                  * The do_for_each_event_file_safe() is
2043                  * a double loop. After finding the call for this
2044                  * trace_array, we use break to jump to the next
2045                  * trace_array.
2046                  */
2047                 break;
2048         } while_for_each_event_file();
2049 }
2050 
2051 static void event_remove(struct trace_event_call *call)
2052 {
2053         struct trace_array *tr;
2054         struct trace_event_file *file;
2055 
2056         do_for_each_event_file(tr, file) {
2057                 if (file->event_call != call)
2058                         continue;
2059 
2060                 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2061                         tr->clear_trace = true;
2062 
2063                 ftrace_event_enable_disable(file, 0);
2064                 /*
2065                  * The do_for_each_event_file() is
2066                  * a double loop. After finding the call for this
2067                  * trace_array, we use break to jump to the next
2068                  * trace_array.
2069                  */
2070                 break;
2071         } while_for_each_event_file();
2072 
2073         if (call->event.funcs)
2074                 __unregister_trace_event(&call->event);
2075         remove_event_from_tracers(call);
2076         list_del(&call->list);
2077 }
2078 
2079 static int event_init(struct trace_event_call *call)
2080 {
2081         int ret = 0;
2082         const char *name;
2083 
2084         name = trace_event_name(call);
2085         if (WARN_ON(!name))
2086                 return -EINVAL;
2087 
2088         if (call->class->raw_init) {
2089                 ret = call->class->raw_init(call);
2090                 if (ret < 0 && ret != -ENOSYS)
2091                         pr_warn("Could not initialize trace events/%s\n", name);
2092         }
2093 
2094         return ret;
2095 }
2096 
2097 static int
2098 __register_event(struct trace_event_call *call, struct module *mod)
2099 {
2100         int ret;
2101 
2102         ret = event_init(call);
2103         if (ret < 0)
2104                 return ret;
2105 
2106         list_add(&call->list, &ftrace_events);
2107         call->mod = mod;
2108 
2109         return 0;
2110 }
2111 
2112 static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2113 {
2114         int rlen;
2115         int elen;
2116 
2117         /* Find the length of the eval value as a string */
2118         elen = snprintf(ptr, 0, "%ld", map->eval_value);
2119         /* Make sure there's enough room to replace the string with the value */
2120         if (len < elen)
2121                 return NULL;
2122 
2123         snprintf(ptr, elen + 1, "%ld", map->eval_value);
2124 
2125         /* Get the rest of the string of ptr */
2126         rlen = strlen(ptr + len);
2127         memmove(ptr + elen, ptr + len, rlen);
2128         /* Make sure we end the new string */
2129         ptr[elen + rlen] = 0;
2130 
2131         return ptr + elen;
2132 }
2133 
2134 static void update_event_printk(struct trace_event_call *call,
2135                                 struct trace_eval_map *map)
2136 {
2137         char *ptr;
2138         int quote = 0;
2139         int len = strlen(map->eval_string);
2140 
2141         for (ptr = call->print_fmt; *ptr; ptr++) {
2142                 if (*ptr == '\\') {
2143                         ptr++;
2144                         /* paranoid */
2145                         if (!*ptr)
2146                                 break;
2147                         continue;
2148                 }
2149                 if (*ptr == '"') {
2150                         quote ^= 1;
2151                         continue;
2152                 }
2153                 if (quote)
2154                         continue;
2155                 if (isdigit(*ptr)) {
2156                         /* skip numbers */
2157                         do {
2158                                 ptr++;
2159                                 /* Check for alpha chars like ULL */
2160                         } while (isalnum(*ptr));
2161                         if (!*ptr)
2162                                 break;
2163                         /*
2164                          * A number must have some kind of delimiter after
2165                          * it, and we can ignore that too.
2166                          */
2167                         continue;
2168                 }
2169                 if (isalpha(*ptr) || *ptr == '_') {
2170                         if (strncmp(map->eval_string, ptr, len) == 0 &&
2171                             !isalnum(ptr[len]) && ptr[len] != '_') {
2172                                 ptr = eval_replace(ptr, map, len);
2173                                 /* enum/sizeof string smaller than value */
2174                                 if (WARN_ON_ONCE(!ptr))
2175                                         return;
2176                                 /*
2177                                  * No need to decrement here, as eval_replace()
2178                                  * returns the pointer to the character passed
2179                                  * the eval, and two evals can not be placed
2180                                  * back to back without something in between.
2181                                  * We can skip that something in between.
2182                                  */
2183                                 continue;
2184                         }
2185                 skip_more:
2186                         do {
2187                                 ptr++;
2188                         } while (isalnum(*ptr) || *ptr == '_');
2189                         if (!*ptr)
2190                                 break;
2191                         /*
2192                          * If what comes after this variable is a '.' or
2193                          * '->' then we can continue to ignore that string.
2194                          */
2195                         if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2196                                 ptr += *ptr == '.' ? 1 : 2;
2197                                 if (!*ptr)
2198                                         break;
2199                                 goto skip_more;
2200                         }
2201                         /*
2202                          * Once again, we can skip the delimiter that came
2203                          * after the string.
2204                          */
2205                         continue;
2206                 }
2207         }
2208 }
2209 
2210 void trace_event_eval_update(struct trace_eval_map **map, int len)
2211 {
2212         struct trace_event_call *call, *p;
2213         const char *last_system = NULL;
2214         bool first = false;
2215         int last_i;
2216         int i;
2217 
2218         down_write(&trace_event_sem);
2219         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2220                 /* events are usually grouped together with systems */
2221                 if (!last_system || call->class->system != last_system) {
2222                         first = true;
2223                         last_i = 0;
2224                         last_system = call->class->system;
2225                 }
2226 
2227                 /*
2228                  * Since calls are grouped by systems, the likelyhood that the
2229                  * next call in the iteration belongs to the same system as the
2230                  * previous call is high. As an optimization, we skip seaching
2231                  * for a map[] that matches the call's system if the last call
2232                  * was from the same system. That's what last_i is for. If the
2233                  * call has the same system as the previous call, then last_i
2234                  * will be the index of the first map[] that has a matching
2235                  * system.
2236                  */
2237                 for (i = last_i; i < len; i++) {
2238                         if (call->class->system == map[i]->system) {
2239                                 /* Save the first system if need be */
2240                                 if (first) {
2241                                         last_i = i;
2242                                         first = false;
2243                                 }
2244                                 update_event_printk(call, map[i]);
2245                         }
2246                 }
2247         }
2248         up_write(&trace_event_sem);
2249 }
2250 
2251 static struct trace_event_file *
2252 trace_create_new_event(struct trace_event_call *call,
2253                        struct trace_array *tr)
2254 {
2255         struct trace_event_file *file;
2256 
2257         file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2258         if (!file)
2259                 return NULL;
2260 
2261         file->event_call = call;
2262         file->tr = tr;
2263         atomic_set(&file->sm_ref, 0);
2264         atomic_set(&file->tm_ref, 0);
2265         INIT_LIST_HEAD(&file->triggers);
2266         list_add(&file->list, &tr->events);
2267 
2268         return file;
2269 }
2270 
2271 /* Add an event to a trace directory */
2272 static int
2273 __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2274 {
2275         struct trace_event_file *file;
2276 
2277         file = trace_create_new_event(call, tr);
2278         if (!file)
2279                 return -ENOMEM;
2280 
2281         return event_create_dir(tr->event_dir, file);
2282 }
2283 
2284 /*
2285  * Just create a decriptor for early init. A descriptor is required
2286  * for enabling events at boot. We want to enable events before
2287  * the filesystem is initialized.
2288  */
2289 static __init int
2290 __trace_early_add_new_event(struct trace_event_call *call,
2291                             struct trace_array *tr)
2292 {
2293         struct trace_event_file *file;
2294 
2295         file = trace_create_new_event(call, tr);
2296         if (!file)
2297                 return -ENOMEM;
2298 
2299         return 0;
2300 }
2301 
2302 struct ftrace_module_file_ops;
2303 static void __add_event_to_tracers(struct trace_event_call *call);
2304 
2305 /* Add an additional event_call dynamically */
2306 int trace_add_event_call(struct trace_event_call *call)
2307 {
2308         int ret;
2309         mutex_lock(&event_mutex);
2310         mutex_lock(&trace_types_lock);
2311 
2312         ret = __register_event(call, NULL);
2313         if (ret >= 0)
2314                 __add_event_to_tracers(call);
2315 
2316         mutex_unlock(&trace_types_lock);
2317         mutex_unlock(&event_mutex);
2318         return ret;
2319 }
2320 
2321 /*
2322  * Must be called under locking of trace_types_lock, event_mutex and
2323  * trace_event_sem.
2324  */
2325 static void __trace_remove_event_call(struct trace_event_call *call)
2326 {
2327         event_remove(call);
2328         trace_destroy_fields(call);
2329         free_event_filter(call->filter);
2330         call->filter = NULL;
2331 }
2332 
2333 static int probe_remove_event_call(struct trace_event_call *call)
2334 {
2335         struct trace_array *tr;
2336         struct trace_event_file *file;
2337 
2338 #ifdef CONFIG_PERF_EVENTS
2339         if (call->perf_refcount)
2340                 return -EBUSY;
2341 #endif
2342         do_for_each_event_file(tr, file) {
2343                 if (file->event_call != call)
2344                         continue;
2345                 /*
2346                  * We can't rely on ftrace_event_enable_disable(enable => 0)
2347                  * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
2348                  * TRACE_REG_UNREGISTER.
2349                  */
2350                 if (file->flags & EVENT_FILE_FL_ENABLED)
2351                         return -EBUSY;
2352                 /*
2353                  * The do_for_each_event_file_safe() is
2354                  * a double loop. After finding the call for this
2355                  * trace_array, we use break to jump to the next
2356                  * trace_array.
2357                  */
2358                 break;
2359         } while_for_each_event_file();
2360 
2361         __trace_remove_event_call(call);
2362 
2363         return 0;
2364 }
2365 
2366 /* Remove an event_call */
2367 int trace_remove_event_call(struct trace_event_call *call)
2368 {
2369         int ret;
2370 
2371         mutex_lock(&event_mutex);
2372         mutex_lock(&trace_types_lock);
2373         down_write(&trace_event_sem);
2374         ret = probe_remove_event_call(call);
2375         up_write(&trace_event_sem);
2376         mutex_unlock(&trace_types_lock);
2377         mutex_unlock(&event_mutex);
2378 
2379         return ret;
2380 }
2381 
2382 #define for_each_event(event, start, end)                       \
2383         for (event = start;                                     \
2384              (unsigned long)event < (unsigned long)end;         \
2385              event++)
2386 
2387 #ifdef CONFIG_MODULES
2388 
2389 static void trace_module_add_events(struct module *mod)
2390 {
2391         struct trace_event_call **call, **start, **end;
2392 
2393         if (!mod->num_trace_events)
2394                 return;
2395 
2396         /* Don't add infrastructure for mods without tracepoints */
2397         if (trace_module_has_bad_taint(mod)) {
2398                 pr_err("%s: module has bad taint, not creating trace events\n",
2399                        mod->name);
2400                 return;
2401         }
2402 
2403         start = mod->trace_events;
2404         end = mod->trace_events + mod->num_trace_events;
2405 
2406         for_each_event(call, start, end) {
2407                 __register_event(*call, mod);
2408                 __add_event_to_tracers(*call);
2409         }
2410 }
2411 
2412 static void trace_module_remove_events(struct module *mod)
2413 {
2414         struct trace_event_call *call, *p;
2415 
2416         down_write(&trace_event_sem);
2417         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2418                 if (call->mod == mod)
2419                         __trace_remove_event_call(call);
2420         }
2421         up_write(&trace_event_sem);
2422 
2423         /*
2424          * It is safest to reset the ring buffer if the module being unloaded
2425          * registered any events that were used. The only worry is if
2426          * a new module gets loaded, and takes on the same id as the events
2427          * of this module. When printing out the buffer, traced events left
2428          * over from this module may be passed to the new module events and
2429          * unexpected results may occur.
2430          */
2431         tracing_reset_all_online_cpus();
2432 }
2433 
2434 static int trace_module_notify(struct notifier_block *self,
2435                                unsigned long val, void *data)
2436 {
2437         struct module *mod = data;
2438 
2439         mutex_lock(&event_mutex);
2440         mutex_lock(&trace_types_lock);
2441         switch (val) {
2442         case MODULE_STATE_COMING:
2443                 trace_module_add_events(mod);
2444                 break;
2445         case MODULE_STATE_GOING:
2446                 trace_module_remove_events(mod);
2447                 break;
2448         }
2449         mutex_unlock(&trace_types_lock);
2450         mutex_unlock(&event_mutex);
2451 
2452         return 0;
2453 }
2454 
2455 static struct notifier_block trace_module_nb = {
2456         .notifier_call = trace_module_notify,
2457         .priority = 1, /* higher than trace.c module notify */
2458 };
2459 #endif /* CONFIG_MODULES */
2460 
2461 /* Create a new event directory structure for a trace directory. */
2462 static void
2463 __trace_add_event_dirs(struct trace_array *tr)
2464 {
2465         struct trace_event_call *call;
2466         int ret;
2467 
2468         list_for_each_entry(call, &ftrace_events, list) {
2469                 ret = __trace_add_new_event(call, tr);
2470                 if (ret < 0)
2471                         pr_warn("Could not create directory for event %s\n",
2472                                 trace_event_name(call));
2473         }
2474 }
2475 
2476 struct trace_event_file *
2477 find_event_file(struct trace_array *tr, const char *system,  const char *event)
2478 {
2479         struct trace_event_file *file;
2480         struct trace_event_call *call;
2481         const char *name;
2482 
2483         list_for_each_entry(file, &tr->events, list) {
2484 
2485                 call = file->event_call;
2486                 name = trace_event_name(call);
2487 
2488                 if (!name || !call->class || !call->class->reg)
2489                         continue;
2490 
2491                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
2492                         continue;
2493 
2494                 if (strcmp(event, name) == 0 &&
2495                     strcmp(system, call->class->system) == 0)
2496                         return file;
2497         }
2498         return NULL;
2499 }
2500 
2501 #ifdef CONFIG_DYNAMIC_FTRACE
2502 
2503 /* Avoid typos */
2504 #define ENABLE_EVENT_STR        "enable_event"
2505 #define DISABLE_EVENT_STR       "disable_event"
2506 
2507 struct event_probe_data {
2508         struct trace_event_file *file;
2509         unsigned long                   count;
2510         int                             ref;
2511         bool                            enable;
2512 };
2513 
2514 static void update_event_probe(struct event_probe_data *data)
2515 {
2516         if (data->enable)
2517                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2518         else
2519                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2520 }
2521 
2522 static void
2523 event_enable_probe(unsigned long ip, unsigned long parent_ip,
2524                    struct trace_array *tr, struct ftrace_probe_ops *ops,
2525                    void *data)
2526 {
2527         struct ftrace_func_mapper *mapper = data;
2528         struct event_probe_data *edata;
2529         void **pdata;
2530 
2531         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2532         if (!pdata || !*pdata)
2533                 return;
2534 
2535         edata = *pdata;
2536         update_event_probe(edata);
2537 }
2538 
2539 static void
2540 event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
2541                          struct trace_array *tr, struct ftrace_probe_ops *ops,
2542                          void *data)
2543 {
2544         struct ftrace_func_mapper *mapper = data;
2545         struct event_probe_data *edata;
2546         void **pdata;
2547 
2548         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2549         if (!pdata || !*pdata)
2550                 return;
2551 
2552         edata = *pdata;
2553 
2554         if (!edata->count)
2555                 return;
2556 
2557         /* Skip if the event is in a state we want to switch to */
2558         if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
2559                 return;
2560 
2561         if (edata->count != -1)
2562                 (edata->count)--;
2563 
2564         update_event_probe(edata);
2565 }
2566 
2567 static int
2568 event_enable_print(struct seq_file *m, unsigned long ip,
2569                    struct ftrace_probe_ops *ops, void *data)
2570 {
2571         struct ftrace_func_mapper *mapper = data;
2572         struct event_probe_data *edata;
2573         void **pdata;
2574 
2575         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2576 
2577         if (WARN_ON_ONCE(!pdata || !*pdata))
2578                 return 0;
2579 
2580         edata = *pdata;
2581 
2582         seq_printf(m, "%ps:", (void *)ip);
2583 
2584         seq_printf(m, "%s:%s:%s",
2585                    edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
2586                    edata->file->event_call->class->system,
2587                    trace_event_name(edata->file->event_call));
2588 
2589         if (edata->count == -1)
2590                 seq_puts(m, ":unlimited\n");
2591         else
2592                 seq_printf(m, ":count=%ld\n", edata->count);
2593 
2594         return 0;
2595 }
2596 
2597 static int
2598 event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
2599                   unsigned long ip, void *init_data, void **data)
2600 {
2601         struct ftrace_func_mapper *mapper = *data;
2602         struct event_probe_data *edata = init_data;
2603         int ret;
2604 
2605         if (!mapper) {
2606                 mapper = allocate_ftrace_func_mapper();
2607                 if (!mapper)
2608                         return -ENODEV;
2609                 *data = mapper;
2610         }
2611 
2612         ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
2613         if (ret < 0)
2614                 return ret;
2615 
2616         edata->ref++;
2617 
2618         return 0;
2619 }
2620 
2621 static int free_probe_data(void *data)
2622 {
2623         struct event_probe_data *edata = data;
2624 
2625         edata->ref--;
2626         if (!edata->ref) {
2627                 /* Remove the SOFT_MODE flag */
2628                 __ftrace_event_enable_disable(edata->file, 0, 1);
2629                 module_put(edata->file->event_call->mod);
2630                 kfree(edata);
2631         }
2632         return 0;
2633 }
2634 
2635 static void
2636 event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
2637                   unsigned long ip, void *data)
2638 {
2639         struct ftrace_func_mapper *mapper = data;
2640         struct event_probe_data *edata;
2641 
2642         if (!ip) {
2643                 if (!mapper)
2644                         return;
2645                 free_ftrace_func_mapper(mapper, free_probe_data);
2646                 return;
2647         }
2648 
2649         edata = ftrace_func_mapper_remove_ip(mapper, ip);
2650 
2651         if (WARN_ON_ONCE(!edata))
2652                 return;
2653 
2654         if (WARN_ON_ONCE(edata->ref <= 0))
2655                 return;
2656 
2657         free_probe_data(edata);
2658 }
2659 
2660 static struct ftrace_probe_ops event_enable_probe_ops = {
2661         .func                   = event_enable_probe,
2662         .print                  = event_enable_print,
2663         .init                   = event_enable_init,
2664         .free                   = event_enable_free,
2665 };
2666 
2667 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2668         .func                   = event_enable_count_probe,
2669         .print                  = event_enable_print,
2670         .init                   = event_enable_init,
2671         .free                   = event_enable_free,
2672 };
2673 
2674 static struct ftrace_probe_ops event_disable_probe_ops = {
2675         .func                   = event_enable_probe,
2676         .print                  = event_enable_print,
2677         .init                   = event_enable_init,
2678         .free                   = event_enable_free,
2679 };
2680 
2681 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2682         .func                   = event_enable_count_probe,
2683         .print                  = event_enable_print,
2684         .init                   = event_enable_init,
2685         .free                   = event_enable_free,
2686 };
2687 
2688 static int
2689 event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
2690                   char *glob, char *cmd, char *param, int enabled)
2691 {
2692         struct trace_event_file *file;
2693         struct ftrace_probe_ops *ops;
2694         struct event_probe_data *data;
2695         const char *system;
2696         const char *event;
2697         char *number;
2698         bool enable;
2699         int ret;
2700 
2701         if (!tr)
2702                 return -ENODEV;
2703 
2704         /* hash funcs only work with set_ftrace_filter */
2705         if (!enabled || !param)
2706                 return -EINVAL;
2707 
2708         system = strsep(&param, ":");
2709         if (!param)
2710                 return -EINVAL;
2711 
2712         event = strsep(&param, ":");
2713 
2714         mutex_lock(&event_mutex);
2715 
2716         ret = -EINVAL;
2717         file = find_event_file(tr, system, event);
2718         if (!file)
2719                 goto out;
2720 
2721         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2722 
2723         if (enable)
2724                 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2725         else
2726                 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2727 
2728         if (glob[0] == '!') {
2729                 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
2730                 goto out;
2731         }
2732 
2733         ret = -ENOMEM;
2734 
2735         data = kzalloc(sizeof(*data), GFP_KERNEL);
2736         if (!data)
2737                 goto out;
2738 
2739         data->enable = enable;
2740         data->count = -1;
2741         data->file = file;
2742 
2743         if (!param)
2744                 goto out_reg;
2745 
2746         number = strsep(&param, ":");
2747 
2748         ret = -EINVAL;
2749         if (!strlen(number))
2750                 goto out_free;
2751 
2752         /*
2753          * We use the callback data field (which is a pointer)
2754          * as our counter.
2755          */
2756         ret = kstrtoul(number, 0, &data->count);
2757         if (ret)
2758                 goto out_free;
2759 
2760  out_reg:
2761         /* Don't let event modules unload while probe registered */
2762         ret = try_module_get(file->event_call->mod);
2763         if (!ret) {
2764                 ret = -EBUSY;
2765                 goto out_free;
2766         }
2767 
2768         ret = __ftrace_event_enable_disable(file, 1, 1);
2769         if (ret < 0)
2770                 goto out_put;
2771 
2772         ret = register_ftrace_function_probe(glob, tr, ops, data);
2773         /*
2774          * The above returns on success the # of functions enabled,
2775          * but if it didn't find any functions it returns zero.
2776          * Consider no functions a failure too.
2777          */
2778         if (!ret) {
2779                 ret = -ENOENT;
2780                 goto out_disable;
2781         } else if (ret < 0)
2782                 goto out_disable;
2783         /* Just return zero, not the number of enabled functions */
2784         ret = 0;
2785  out:
2786         mutex_unlock(&event_mutex);
2787         return ret;
2788 
2789  out_disable:
2790         __ftrace_event_enable_disable(file, 0, 1);
2791  out_put:
2792         module_put(file->event_call->mod);
2793  out_free:
2794         kfree(data);
2795         goto out;
2796 }
2797 
2798 static struct ftrace_func_command event_enable_cmd = {
2799         .name                   = ENABLE_EVENT_STR,
2800         .func                   = event_enable_func,
2801 };
2802 
2803 static struct ftrace_func_command event_disable_cmd = {
2804         .name                   = DISABLE_EVENT_STR,
2805         .func                   = event_enable_func,
2806 };
2807 
2808 static __init int register_event_cmds(void)
2809 {
2810         int ret;
2811 
2812         ret = register_ftrace_command(&event_enable_cmd);
2813         if (WARN_ON(ret < 0))
2814                 return ret;
2815         ret = register_ftrace_command(&event_disable_cmd);
2816         if (WARN_ON(ret < 0))
2817                 unregister_ftrace_command(&event_enable_cmd);
2818         return ret;
2819 }
2820 #else
2821 static inline int register_event_cmds(void) { return 0; }
2822 #endif /* CONFIG_DYNAMIC_FTRACE */
2823 
2824 /*
2825  * The top level array has already had its trace_event_file
2826  * descriptors created in order to allow for early events to
2827  * be recorded. This function is called after the tracefs has been
2828  * initialized, and we now have to create the files associated
2829  * to the events.
2830  */
2831 static __init void
2832 __trace_early_add_event_dirs(struct trace_array *tr)
2833 {
2834         struct trace_event_file *file;
2835         int ret;
2836 
2837 
2838         list_for_each_entry(file, &tr->events, list) {
2839                 ret = event_create_dir(tr->event_dir, file);
2840                 if (ret < 0)
2841                         pr_warn("Could not create directory for event %s\n",
2842                                 trace_event_name(file->event_call));
2843         }
2844 }
2845 
2846 /*
2847  * For early boot up, the top trace array requires to have
2848  * a list of events that can be enabled. This must be done before
2849  * the filesystem is set up in order to allow events to be traced
2850  * early.
2851  */
2852 static __init void
2853 __trace_early_add_events(struct trace_array *tr)
2854 {
2855         struct trace_event_call *call;
2856         int ret;
2857 
2858         list_for_each_entry(call, &ftrace_events, list) {
2859                 /* Early boot up should not have any modules loaded */
2860                 if (WARN_ON_ONCE(call->mod))
2861                         continue;
2862 
2863                 ret = __trace_early_add_new_event(call, tr);
2864                 if (ret < 0)
2865                         pr_warn("Could not create early event %s\n",
2866                                 trace_event_name(call));
2867         }
2868 }
2869 
2870 /* Remove the event directory structure for a trace directory. */
2871 static void
2872 __trace_remove_event_dirs(struct trace_array *tr)
2873 {
2874         struct trace_event_file *file, *next;
2875 
2876         list_for_each_entry_safe(file, next, &tr->events, list)
2877                 remove_event_file_dir(file);
2878 }
2879 
2880 static void __add_event_to_tracers(struct trace_event_call *call)
2881 {
2882         struct trace_array *tr;
2883 
2884         list_for_each_entry(tr, &ftrace_trace_arrays, list)
2885                 __trace_add_new_event(call, tr);
2886 }
2887 
2888 extern struct trace_event_call *__start_ftrace_events[];
2889 extern struct trace_event_call *__stop_ftrace_events[];
2890 
2891 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2892 
2893 static __init int setup_trace_event(char *str)
2894 {
2895         strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2896         ring_buffer_expanded = true;
2897         tracing_selftest_disabled = true;
2898 
2899         return 1;
2900 }
2901 __setup("trace_event=", setup_trace_event);
2902 
2903 /* Expects to have event_mutex held when called */
2904 static int
2905 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2906 {
2907         struct dentry *d_events;
2908         struct dentry *entry;
2909 
2910         entry = tracefs_create_file("set_event", 0644, parent,
2911                                     tr, &ftrace_set_event_fops);
2912         if (!entry) {
2913                 pr_warn("Could not create tracefs 'set_event' entry\n");
2914                 return -ENOMEM;
2915         }
2916 
2917         d_events = tracefs_create_dir("events", parent);
2918         if (!d_events) {
2919                 pr_warn("Could not create tracefs 'events' directory\n");
2920                 return -ENOMEM;
2921         }
2922 
2923         entry = trace_create_file("enable", 0644, d_events,
2924                                   tr, &ftrace_tr_enable_fops);
2925         if (!entry) {
2926                 pr_warn("Could not create tracefs 'enable' entry\n");
2927                 return -ENOMEM;
2928         }
2929 
2930         /* There are not as crucial, just warn if they are not created */
2931 
2932         entry = tracefs_create_file("set_event_pid", 0644, parent,
2933                                     tr, &ftrace_set_event_pid_fops);
2934         if (!entry)
2935                 pr_warn("Could not create tracefs 'set_event_pid' entry\n");
2936 
2937         /* ring buffer internal formats */
2938         entry = trace_create_file("header_page", 0444, d_events,
2939                                   ring_buffer_print_page_header,
2940                                   &ftrace_show_header_fops);
2941         if (!entry)
2942                 pr_warn("Could not create tracefs 'header_page' entry\n");
2943 
2944         entry = trace_create_file("header_event", 0444, d_events,
2945                                   ring_buffer_print_entry_header,
2946                                   &ftrace_show_header_fops);
2947         if (!entry)
2948                 pr_warn("Could not create tracefs 'header_event' entry\n");
2949 
2950         tr->event_dir = d_events;
2951 
2952         return 0;
2953 }
2954 
2955 /**
2956  * event_trace_add_tracer - add a instance of a trace_array to events
2957  * @parent: The parent dentry to place the files/directories for events in
2958  * @tr: The trace array associated with these events
2959  *
2960  * When a new instance is created, it needs to set up its events
2961  * directory, as well as other files associated with events. It also
2962  * creates the event hierachry in the @parent/events directory.
2963  *
2964  * Returns 0 on success.
2965  *
2966  * Must be called with event_mutex held.
2967  */
2968 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2969 {
2970         int ret;
2971 
2972         lockdep_assert_held(&event_mutex);
2973 
2974         ret = create_event_toplevel_files(parent, tr);
2975         if (ret)
2976                 goto out;
2977 
2978         down_write(&trace_event_sem);
2979         __trace_add_event_dirs(tr);
2980         up_write(&trace_event_sem);
2981 
2982  out:
2983         return ret;
2984 }
2985 
2986 /*
2987  * The top trace array already had its file descriptors created.
2988  * Now the files themselves need to be created.
2989  */
2990 static __init int
2991 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2992 {
2993         int ret;
2994 
2995         mutex_lock(&event_mutex);
2996 
2997         ret = create_event_toplevel_files(parent, tr);
2998         if (ret)
2999                 goto out_unlock;
3000 
3001         down_write(&trace_event_sem);
3002         __trace_early_add_event_dirs(tr);
3003         up_write(&trace_event_sem);
3004 
3005  out_unlock:
3006         mutex_unlock(&event_mutex);
3007 
3008         return ret;
3009 }
3010 
3011 /* Must be called with event_mutex held */
3012 int event_trace_del_tracer(struct trace_array *tr)
3013 {
3014         lockdep_assert_held(&event_mutex);
3015 
3016         /* Disable any event triggers and associated soft-disabled events */
3017         clear_event_triggers(tr);
3018 
3019         /* Clear the pid list */
3020         __ftrace_clear_event_pids(tr);
3021 
3022         /* Disable any running events */
3023         __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3024 
3025         /* Access to events are within rcu_read_lock_sched() */
3026         synchronize_sched();
3027 
3028         down_write(&trace_event_sem);
3029         __trace_remove_event_dirs(tr);
3030         tracefs_remove_recursive(tr->event_dir);
3031         up_write(&trace_event_sem);
3032 
3033         tr->event_dir = NULL;
3034 
3035         return 0;
3036 }
3037 
3038 static __init int event_trace_memsetup(void)
3039 {
3040         field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3041         file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3042         return 0;
3043 }
3044 
3045 static __init void
3046 early_enable_events(struct trace_array *tr, bool disable_first)
3047 {
3048         char *buf = bootup_event_buf;
3049         char *token;
3050         int ret;
3051 
3052         while (true) {
3053                 token = strsep(&buf, ",");
3054 
3055                 if (!token)
3056                         break;
3057 
3058                 if (*token) {
3059                         /* Restarting syscalls requires that we stop them first */
3060                         if (disable_first)
3061                                 ftrace_set_clr_event(tr, token, 0);
3062 
3063                         ret = ftrace_set_clr_event(tr, token, 1);
3064                         if (ret)
3065                                 pr_warn("Failed to enable trace event: %s\n", token);
3066                 }
3067 
3068                 /* Put back the comma to allow this to be called again */
3069                 if (buf)
3070                         *(buf - 1) = ',';
3071         }
3072 }
3073 
3074 static __init int event_trace_enable(void)
3075 {
3076         struct trace_array *tr = top_trace_array();
3077         struct trace_event_call **iter, *call;
3078         int ret;
3079 
3080         if (!tr)
3081                 return -ENODEV;
3082 
3083         for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3084 
3085                 call = *iter;
3086                 ret = event_init(call);
3087                 if (!ret)
3088                         list_add(&call->list, &ftrace_events);
3089         }
3090 
3091         /*
3092          * We need the top trace array to have a working set of trace
3093          * points at early init, before the debug files and directories
3094          * are created. Create the file entries now, and attach them
3095          * to the actual file dentries later.
3096          */
3097         __trace_early_add_events(tr);
3098 
3099         early_enable_events(tr, false);
3100 
3101         trace_printk_start_comm();
3102 
3103         register_event_cmds();
3104 
3105         register_trigger_cmds();
3106 
3107         return 0;
3108 }
3109 
3110 /*
3111  * event_trace_enable() is called from trace_event_init() first to
3112  * initialize events and perhaps start any events that are on the
3113  * command line. Unfortunately, there are some events that will not
3114  * start this early, like the system call tracepoints that need
3115  * to set the TIF_SYSCALL_TRACEPOINT flag of pid 1. But event_trace_enable()
3116  * is called before pid 1 starts, and this flag is never set, making
3117  * the syscall tracepoint never get reached, but the event is enabled
3118  * regardless (and not doing anything).
3119  */
3120 static __init int event_trace_enable_again(void)
3121 {
3122         struct trace_array *tr;
3123 
3124         tr = top_trace_array();
3125         if (!tr)
3126                 return -ENODEV;
3127 
3128         early_enable_events(tr, true);
3129 
3130         return 0;
3131 }
3132 
3133 early_initcall(event_trace_enable_again);
3134 
3135 static __init int event_trace_init(void)
3136 {
3137         struct trace_array *tr;
3138         struct dentry *d_tracer;
3139         struct dentry *entry;
3140         int ret;
3141 
3142         tr = top_trace_array();
3143         if (!tr)
3144                 return -ENODEV;
3145 
3146         d_tracer = tracing_init_dentry();
3147         if (IS_ERR(d_tracer))
3148                 return 0;
3149 
3150         entry = tracefs_create_file("available_events", 0444, d_tracer,
3151                                     tr, &ftrace_avail_fops);
3152         if (!entry)
3153                 pr_warn("Could not create tracefs 'available_events' entry\n");
3154 
3155         if (trace_define_generic_fields())
3156                 pr_warn("tracing: Failed to allocated generic fields");
3157 
3158         if (trace_define_common_fields())
3159                 pr_warn("tracing: Failed to allocate common fields");
3160 
3161         ret = early_event_add_tracer(d_tracer, tr);
3162         if (ret)
3163                 return ret;
3164 
3165 #ifdef CONFIG_MODULES
3166         ret = register_module_notifier(&trace_module_nb);
3167         if (ret)
3168                 pr_warn("Failed to register trace events module notifier\n");
3169 #endif
3170         return 0;
3171 }
3172 
3173 void __init trace_event_init(void)
3174 {
3175         event_trace_memsetup();
3176         init_ftrace_syscalls();
3177         event_trace_enable();
3178 }
3179 
3180 fs_initcall(event_trace_init);
3181 
3182 #ifdef CONFIG_FTRACE_STARTUP_TEST
3183 
3184 static DEFINE_SPINLOCK(test_spinlock);
3185 static DEFINE_SPINLOCK(test_spinlock_irq);
3186 static DEFINE_MUTEX(test_mutex);
3187 
3188 static __init void test_work(struct work_struct *dummy)
3189 {
3190         spin_lock(&test_spinlock);
3191         spin_lock_irq(&test_spinlock_irq);
3192         udelay(1);
3193         spin_unlock_irq(&test_spinlock_irq);
3194         spin_unlock(&test_spinlock);
3195 
3196         mutex_lock(&test_mutex);
3197         msleep(1);
3198         mutex_unlock(&test_mutex);
3199 }
3200 
3201 static __init int event_test_thread(void *unused)
3202 {
3203         void *test_malloc;
3204 
3205         test_malloc = kmalloc(1234, GFP_KERNEL);
3206         if (!test_malloc)
3207                 pr_info("failed to kmalloc\n");
3208 
3209         schedule_on_each_cpu(test_work);
3210 
3211         kfree(test_malloc);
3212 
3213         set_current_state(TASK_INTERRUPTIBLE);
3214         while (!kthread_should_stop()) {
3215                 schedule();
3216                 set_current_state(TASK_INTERRUPTIBLE);
3217         }
3218         __set_current_state(TASK_RUNNING);
3219 
3220         return 0;
3221 }
3222 
3223 /*
3224  * Do various things that may trigger events.
3225  */
3226 static __init void event_test_stuff(void)
3227 {
3228         struct task_struct *test_thread;
3229 
3230         test_thread = kthread_run(event_test_thread, NULL, "test-events");
3231         msleep(1);
3232         kthread_stop(test_thread);
3233 }
3234 
3235 /*
3236  * For every trace event defined, we will test each trace point separately,
3237  * and then by groups, and finally all trace points.
3238  */
3239 static __init void event_trace_self_tests(void)
3240 {
3241         struct trace_subsystem_dir *dir;
3242         struct trace_event_file *file;
3243         struct trace_event_call *call;
3244         struct event_subsystem *system;
3245         struct trace_array *tr;
3246         int ret;
3247 
3248         tr = top_trace_array();
3249         if (!tr)
3250                 return;
3251 
3252         pr_info("Running tests on trace events:\n");
3253 
3254         list_for_each_entry(file, &tr->events, list) {
3255 
3256                 call = file->event_call;
3257 
3258                 /* Only test those that have a probe */
3259                 if (!call->class || !call->class->probe)
3260                         continue;
3261 
3262 /*
3263  * Testing syscall events here is pretty useless, but
3264  * we still do it if configured. But this is time consuming.
3265  * What we really need is a user thread to perform the
3266  * syscalls as we test.
3267  */
3268 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
3269                 if (call->class->system &&
3270                     strcmp(call->class->system, "syscalls") == 0)
3271                         continue;
3272 #endif
3273 
3274                 pr_info("Testing event %s: ", trace_event_name(call));
3275 
3276                 /*
3277                  * If an event is already enabled, someone is using
3278                  * it and the self test should not be on.
3279                  */
3280                 if (file->flags & EVENT_FILE_FL_ENABLED) {
3281                         pr_warn("Enabled event during self test!\n");
3282                         WARN_ON_ONCE(1);
3283                         continue;
3284                 }
3285 
3286                 ftrace_event_enable_disable(file, 1);
3287                 event_test_stuff();
3288                 ftrace_event_enable_disable(file, 0);
3289 
3290                 pr_cont("OK\n");
3291         }
3292 
3293         /* Now test at the sub system level */
3294 
3295         pr_info("Running tests on trace event systems:\n");
3296 
3297         list_for_each_entry(dir, &tr->systems, list) {
3298 
3299                 system = dir->subsystem;
3300 
3301                 /* the ftrace system is special, skip it */
3302                 if (strcmp(system->name, "ftrace") == 0)
3303                         continue;
3304 
3305                 pr_info("Testing event system %s: ", system->name);
3306 
3307                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
3308                 if (WARN_ON_ONCE(ret)) {
3309                         pr_warn("error enabling system %s\n",
3310                                 system->name);
3311                         continue;
3312                 }
3313 
3314                 event_test_stuff();
3315 
3316                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
3317                 if (WARN_ON_ONCE(ret)) {
3318                         pr_warn("error disabling system %s\n",
3319                                 system->name);
3320                         continue;
3321                 }
3322 
3323                 pr_cont("OK\n");
3324         }
3325 
3326         /* Test with all events enabled */
3327 
3328         pr_info("Running tests on all trace events:\n");
3329         pr_info("Testing all events: ");
3330 
3331         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
3332         if (WARN_ON_ONCE(ret)) {
3333                 pr_warn("error enabling all events\n");
3334                 return;
3335         }
3336 
3337         event_test_stuff();
3338 
3339         /* reset sysname */
3340         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
3341         if (WARN_ON_ONCE(ret)) {
3342                 pr_warn("error disabling all events\n");
3343                 return;
3344         }
3345 
3346         pr_cont("OK\n");
3347 }
3348 
3349 #ifdef CONFIG_FUNCTION_TRACER
3350 
3351 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
3352 
3353 static struct trace_event_file event_trace_file __initdata;
3354 
3355 static void __init
3356 function_test_events_call(unsigned long ip, unsigned long parent_ip,
3357                           struct ftrace_ops *op, struct pt_regs *pt_regs)
3358 {
3359         struct ring_buffer_event *event;
3360         struct ring_buffer *buffer;
3361         struct ftrace_entry *entry;
3362         unsigned long flags;
3363         long disabled;
3364         int cpu;
3365         int pc;
3366 
3367         pc = preempt_count();
3368         preempt_disable_notrace();
3369         cpu = raw_smp_processor_id();
3370         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
3371 
3372         if (disabled != 1)
3373                 goto out;
3374 
3375         local_save_flags(flags);
3376 
3377         event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
3378                                                 TRACE_FN, sizeof(*entry),
3379                                                 flags, pc);
3380         if (!event)
3381                 goto out;
3382         entry   = ring_buffer_event_data(event);
3383         entry->ip                       = ip;
3384         entry->parent_ip                = parent_ip;
3385 
3386         event_trigger_unlock_commit(&event_trace_file, buffer, event,
3387                                     entry, flags, pc);
3388  out:
3389         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
3390         preempt_enable_notrace();
3391 }
3392 
3393 static struct ftrace_ops trace_ops __initdata  =
3394 {
3395         .func = function_test_events_call,
3396         .flags = FTRACE_OPS_FL_RECURSION_SAFE,
3397 };
3398 
3399 static __init void event_trace_self_test_with_function(void)
3400 {
3401         int ret;
3402 
3403         event_trace_file.tr = top_trace_array();
3404         if (WARN_ON(!event_trace_file.tr))
3405                 return;
3406 
3407         ret = register_ftrace_function(&trace_ops);
3408         if (WARN_ON(ret < 0)) {
3409                 pr_info("Failed to enable function tracer for event tests\n");
3410                 return;
3411         }
3412         pr_info("Running tests again, along with the function tracer\n");
3413         event_trace_self_tests();
3414         unregister_ftrace_function(&trace_ops);
3415 }
3416 #else
3417 static __init void event_trace_self_test_with_function(void)
3418 {
3419 }
3420 #endif
3421 
3422 static __init int event_trace_self_tests_init(void)
3423 {
3424         if (!tracing_selftest_disabled) {
3425                 event_trace_self_tests();
3426                 event_trace_self_test_with_function();
3427         }
3428 
3429         return 0;
3430 }
3431 
3432 late_initcall(event_trace_self_tests_init);
3433 
3434 #endif
3435 

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