kernel/trace/trace_events.c

   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] = "0";
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] = { '?', '0', '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