kernel/trace/trace_events.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * event tracer
   4  *
   5  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
   6  *
   7  *  - Added format output of fields of the trace point.
   8  *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
   9  *
  10  */
  11
  12 #define pr_fmt(fmt) fmt
  13
  14 #include <linux/workqueue.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/kthread.h>
  17 #include <linux/tracefs.h>
  18 #include <linux/uaccess.h>
  19 #include <linux/module.h>
  20 #include <linux/ctype.h>
  21 #include <linux/sort.h>
  22 #include <linux/slab.h>
  23 #include <linux/delay.h>
  24
  25 #include <trace/events/sched.h>
  26
  27 #include <asm/setup.h>
  28
  29 #include "trace_output.h"
  30
  31 #undef TRACE_SYSTEM
  32 #define TRACE_SYSTEM "TRACE_SYSTEM"
  33
  34 DEFINE_MUTEX(event_mutex);
  35
  36 LIST_HEAD(ftrace_events);
  37 static LIST_HEAD(ftrace_generic_fields);
  38 static LIST_HEAD(ftrace_common_fields);
  39
  40 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
  41
  42 static struct kmem_cache *field_cachep;
  43 static struct kmem_cache *file_cachep;
  44
  45 static inline int system_refcount(struct event_subsystem *system)
  46 {
  47         return system->ref_count;
  48 }
  49
  50 static int system_refcount_inc(struct event_subsystem *system)
  51 {
  52         return system->ref_count++;
  53 }
  54
  55 static int system_refcount_dec(struct event_subsystem *system)
  56 {
  57         return --system->ref_count;
  58 }
  59
  60 /* Double loops, do not use break, only goto's work */
  61 #define do_for_each_event_file(tr, file)                        \
  62         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
  63                 list_for_each_entry(file, &tr->events, list)
  64
  65 #define do_for_each_event_file_safe(tr, file)                   \
  66         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
  67                 struct trace_event_file *___n;                          \
  68                 list_for_each_entry_safe(file, ___n, &tr->events, list)
  69
  70 #define while_for_each_event_file()             \
  71         }
  72
  73 static struct list_head *
  74 trace_get_fields(struct trace_event_call *event_call)
  75 {
  76         if (!event_call->class->get_fields)
  77                 return &event_call->class->fields;
  78         return event_call->class->get_fields(event_call);
  79 }
  80
  81 static struct ftrace_event_field *
  82 __find_event_field(struct list_head *head, char *name)
  83 {
  84         struct ftrace_event_field *field;
  85
  86         list_for_each_entry(field, head, link) {
  87                 if (!strcmp(field->name, name))
  88                         return field;
  89         }
  90
  91         return NULL;
  92 }
  93
  94 struct ftrace_event_field *
  95 trace_find_event_field(struct trace_event_call *call, char *name)
  96 {
  97         struct ftrace_event_field *field;
  98         struct list_head *head;
  99
 100         head = trace_get_fields(call);
 101         field = __find_event_field(head, name);
 102         if (field)
 103                 return field;
 104
 105         field = __find_event_field(&ftrace_generic_fields, name);
 106         if (field)
 107                 return field;
 108
 109         return __find_event_field(&ftrace_common_fields, name);
 110 }
 111
 112 static int __trace_define_field(struct list_head *head, const char *type,
 113                                 const char *name, int offset, int size,
 114                                 int is_signed, int filter_type)
 115 {
 116         struct ftrace_event_field *field;
 117
 118         field = kmem_cache_alloc(field_cachep, GFP_TRACE);
 119         if (!field)
 120                 return -ENOMEM;
 121
 122         field->name = name;
 123         field->type = type;
 124
 125         if (filter_type == FILTER_OTHER)
 126                 field->filter_type = filter_assign_type(type);
 127         else
 128                 field->filter_type = filter_type;
 129
 130         field->offset = offset;
 131         field->size = size;
 132         field->is_signed = is_signed;
 133
 134         list_add(&field->link, head);
 135
 136         return 0;
 137 }
 138
 139 int trace_define_field(struct trace_event_call *call, const char *type,
 140                        const char *name, int offset, int size, int is_signed,
 141                        int filter_type)
 142 {
 143         struct list_head *head;
 144
 145         if (WARN_ON(!call->class))
 146                 return 0;
 147
 148         head = trace_get_fields(call);
 149         return __trace_define_field(head, type, name, offset, size,
 150                                     is_signed, filter_type);
 151 }
 152 EXPORT_SYMBOL_GPL(trace_define_field);
 153
 154 #define __generic_field(type, item, filter_type)                        \
 155         ret = __trace_define_field(&ftrace_generic_fields, #type,       \
 156                                    #item, 0, 0, is_signed_type(type),   \
 157                                    filter_type);                        \
 158         if (ret)                                                        \
 159                 return ret;
 160
 161 #define __common_field(type, item)                                      \
 162         ret = __trace_define_field(&ftrace_common_fields, #type,        \
 163                                    "common_" #item,                     \
 164                                    offsetof(typeof(ent), item),         \
 165                                    sizeof(ent.item),                    \
 166                                    is_signed_type(type), FILTER_OTHER); \
 167         if (ret)                                                        \
 168                 return ret;
 169
 170 static int trace_define_generic_fields(void)
 171 {
 172         int ret;
 173
 174         __generic_field(int, CPU, FILTER_CPU);
 175         __generic_field(int, cpu, FILTER_CPU);
 176         __generic_field(char *, COMM, FILTER_COMM);
 177         __generic_field(char *, comm, FILTER_COMM);
 178
 179         return ret;
 180 }
 181
 182 static int trace_define_common_fields(void)
 183 {
 184         int ret;
 185         struct trace_entry ent;
 186
 187         __common_field(unsigned short, type);
 188         __common_field(unsigned char, flags);
 189         __common_field(unsigned char, preempt_count);
 190         __common_field(int, pid);
 191
 192         return ret;
 193 }
 194
 195 static void trace_destroy_fields(struct trace_event_call *call)
 196 {
 197         struct ftrace_event_field *field, *next;
 198         struct list_head *head;
 199
 200         head = trace_get_fields(call);
 201         list_for_each_entry_safe(field, next, head, link) {
 202                 list_del(&field->link);
 203                 kmem_cache_free(field_cachep, field);
 204         }
 205 }
 206
 207 /*
 208  * run-time version of trace_event_get_offsets_<call>() that returns the last
 209  * accessible offset of trace fields excluding __dynamic_array bytes
 210  */
 211 int trace_event_get_offsets(struct trace_event_call *call)
 212 {
 213         struct ftrace_event_field *tail;
 214         struct list_head *head;
 215
 216         head = trace_get_fields(call);
 217         /*
 218          * head->next points to the last field with the largest offset,
 219          * since it was added last by trace_define_field()
 220          */
 221         tail = list_first_entry(head, struct ftrace_event_field, link);
 222         return tail->offset + tail->size;
 223 }
 224
 225 int trace_event_raw_init(struct trace_event_call *call)
 226 {
 227         int id;
 228
 229         id = register_trace_event(&call->event);
 230         if (!id)
 231                 return -ENODEV;
 232
 233         return 0;
 234 }
 235 EXPORT_SYMBOL_GPL(trace_event_raw_init);
 236
 237 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
 238 {
 239         struct trace_array *tr = trace_file->tr;
 240         struct trace_array_cpu *data;
 241         struct trace_pid_list *pid_list;
 242
 243         pid_list = rcu_dereference_raw(tr->filtered_pids);
 244         if (!pid_list)
 245                 return false;
 246
 247         data = this_cpu_ptr(tr->trace_buffer.data);
 248
 249         return data->ignore_pid;
 250 }
 251 EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
 252
 253 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 254                                  struct trace_event_file *trace_file,
 255                                  unsigned long len)
 256 {
 257         struct trace_event_call *event_call = trace_file->event_call;
 258
 259         if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
 260             trace_event_ignore_this_pid(trace_file))
 261                 return NULL;
 262
 263         local_save_flags(fbuffer->flags);
 264         fbuffer->pc = preempt_count();
 265         /*
 266          * If CONFIG_PREEMPT is enabled, then the tracepoint itself disables
 267          * preemption (adding one to the preempt_count). Since we are
 268          * interested in the preempt_count at the time the tracepoint was
 269          * hit, we need to subtract one to offset the increment.
 270          */
 271         if (IS_ENABLED(CONFIG_PREEMPT))
 272                 fbuffer->pc--;
 273         fbuffer->trace_file = trace_file;
 274
 275         fbuffer->event =
 276                 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
 277                                                 event_call->event.type, len,
 278                                                 fbuffer->flags, fbuffer->pc);
 279         if (!fbuffer->event)
 280                 return NULL;
 281
 282         fbuffer->entry = ring_buffer_event_data(fbuffer->event);
 283         return fbuffer->entry;
 284 }
 285 EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
 286
 287 int trace_event_reg(struct trace_event_call *call,
 288                     enum trace_reg type, void *data)
 289 {
 290         struct trace_event_file *file = data;
 291
 292         WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
 293         switch (type) {
 294         case TRACE_REG_REGISTER:
 295                 return tracepoint_probe_register(call->tp,
 296                                                  call->class->probe,
 297                                                  file);
 298         case TRACE_REG_UNREGISTER:
 299                 tracepoint_probe_unregister(call->tp,
 300                                             call->class->probe,
 301                                             file);
 302                 return 0;
 303
 304 #ifdef CONFIG_PERF_EVENTS
 305         case TRACE_REG_PERF_REGISTER:
 306                 return tracepoint_probe_register(call->tp,
 307                                                  call->class->perf_probe,
 308                                                  call);
 309         case TRACE_REG_PERF_UNREGISTER:
 310                 tracepoint_probe_unregister(call->tp,
 311                                             call->class->perf_probe,
 312                                             call);
 313                 return 0;
 314         case TRACE_REG_PERF_OPEN:
 315         case TRACE_REG_PERF_CLOSE:
 316         case TRACE_REG_PERF_ADD:
 317         case TRACE_REG_PERF_DEL:
 318                 return 0;
 319 #endif
 320         }
 321         return 0;
 322 }
 323 EXPORT_SYMBOL_GPL(trace_event_reg);
 324
 325 void trace_event_enable_cmd_record(bool enable)
 326 {
 327         struct trace_event_file *file;
 328         struct trace_array *tr;
 329
 330         lockdep_assert_held(&event_mutex);
 331
 332         do_for_each_event_file(tr, file) {
 333
 334                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
 335                         continue;
 336
 337                 if (enable) {
 338                         tracing_start_cmdline_record();
 339                         set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 340                 } else {
 341                         tracing_stop_cmdline_record();
 342                         clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 343                 }
 344         } while_for_each_event_file();
 345 }
 346
 347 void trace_event_enable_tgid_record(bool enable)
 348 {
 349         struct trace_event_file *file;
 350         struct trace_array *tr;
 351
 352         lockdep_assert_held(&event_mutex);
 353
 354         do_for_each_event_file(tr, file) {
 355                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
 356                         continue;
 357
 358                 if (enable) {
 359                         tracing_start_tgid_record();
 360                         set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 361                 } else {
 362                         tracing_stop_tgid_record();
 363                         clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
 364                                   &file->flags);
 365                 }
 366         } while_for_each_event_file();
 367 }
 368
 369 static int __ftrace_event_enable_disable(struct trace_event_file *file,
 370                                          int enable, int soft_disable)
 371 {
 372         struct trace_event_call *call = file->event_call;
 373         struct trace_array *tr = file->tr;
 374         unsigned long file_flags = file->flags;
 375         int ret = 0;
 376         int disable;
 377
 378         switch (enable) {
 379         case 0:
 380                 /*
 381                  * When soft_disable is set and enable is cleared, the sm_ref
 382                  * reference counter is decremented. If it reaches 0, we want
 383                  * to clear the SOFT_DISABLED flag but leave the event in the
 384                  * state that it was. That is, if the event was enabled and
 385                  * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
 386                  * is set we do not want the event to be enabled before we
 387                  * clear the bit.
 388                  *
 389                  * When soft_disable is not set but the SOFT_MODE flag is,
 390                  * we do nothing. Do not disable the tracepoint, otherwise
 391                  * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
 392                  */
 393                 if (soft_disable) {
 394                         if (atomic_dec_return(&file->sm_ref) > 0)
 395                                 break;
 396                         disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
 397                         clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 398                 } else
 399                         disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
 400
 401                 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
 402                         clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 403                         if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
 404                                 tracing_stop_cmdline_record();
 405                                 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 406                         }
 407
 408                         if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
 409                                 tracing_stop_tgid_record();
 410                                 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 411                         }
 412
 413                         call->class->reg(call, TRACE_REG_UNREGISTER, file);
 414                 }
 415                 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
 416                 if (file->flags & EVENT_FILE_FL_SOFT_MODE)
 417                         set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 418                 else
 419                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 420                 break;
 421         case 1:
 422                 /*
 423                  * When soft_disable is set and enable is set, we want to
 424                  * register the tracepoint for the event, but leave the event
 425                  * as is. That means, if the event was already enabled, we do
 426                  * nothing (but set SOFT_MODE). If the event is disabled, we
 427                  * set SOFT_DISABLED before enabling the event tracepoint, so
 428                  * it still seems to be disabled.
 429                  */
 430                 if (!soft_disable)
 431                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 432                 else {
 433                         if (atomic_inc_return(&file->sm_ref) > 1)
 434                                 break;
 435                         set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 436                 }
 437
 438                 if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
 439                         bool cmd = false, tgid = false;
 440
 441                         /* Keep the event disabled, when going to SOFT_MODE. */
 442                         if (soft_disable)
 443                                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 444
 445                         if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
 446                                 cmd = true;
 447                                 tracing_start_cmdline_record();
 448                                 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 449                         }
 450
 451                         if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
 452                                 tgid = true;
 453                                 tracing_start_tgid_record();
 454                                 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 455                         }
 456
 457                         ret = call->class->reg(call, TRACE_REG_REGISTER, file);
 458                         if (ret) {
 459                                 if (cmd)
 460                                         tracing_stop_cmdline_record();
 461                                 if (tgid)
 462                                         tracing_stop_tgid_record();
 463                                 pr_info("event trace: Could not enable event "
 464                                         "%s\n", trace_event_name(call));
 465                                 break;
 466                         }
 467                         set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 468
 469                         /* WAS_ENABLED gets set but never cleared. */
 470                         set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
 471                 }
 472                 break;
 473         }
 474
 475         /* Enable or disable use of trace_buffered_event */
 476         if ((file_flags & EVENT_FILE_FL_SOFT_DISABLED) !=
 477             (file->flags & EVENT_FILE_FL_SOFT_DISABLED)) {
 478                 if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
 479                         trace_buffered_event_enable();
 480                 else
 481                         trace_buffered_event_disable();
 482         }
 483
 484         return ret;
 485 }
 486
 487 int trace_event_enable_disable(struct trace_event_file *file,
 488                                int enable, int soft_disable)
 489 {
 490         return __ftrace_event_enable_disable(file, enable, soft_disable);
 491 }
 492
 493 static int ftrace_event_enable_disable(struct trace_event_file *file,
 494                                        int enable)
 495 {
 496         return __ftrace_event_enable_disable(file, enable, 0);
 497 }
 498
 499 static void ftrace_clear_events(struct trace_array *tr)
 500 {
 501         struct trace_event_file *file;
 502
 503         mutex_lock(&event_mutex);
 504         list_for_each_entry(file, &tr->events, list) {
 505                 ftrace_event_enable_disable(file, 0);
 506         }
 507         mutex_unlock(&event_mutex);
 508 }
 509
 510 static void
 511 event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
 512 {
 513         struct trace_pid_list *pid_list;
 514         struct trace_array *tr = data;
 515
 516         pid_list = rcu_dereference_raw(tr->filtered_pids);
 517         trace_filter_add_remove_task(pid_list, NULL, task);
 518 }
 519
 520 static void
 521 event_filter_pid_sched_process_fork(void *data,
 522                                     struct task_struct *self,
 523                                     struct task_struct *task)
 524 {
 525         struct trace_pid_list *pid_list;
 526         struct trace_array *tr = data;
 527
 528         pid_list = rcu_dereference_sched(tr->filtered_pids);
 529         trace_filter_add_remove_task(pid_list, self, task);
 530 }
 531
 532 void trace_event_follow_fork(struct trace_array *tr, bool enable)
 533 {
 534         if (enable) {
 535                 register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
 536                                                        tr, INT_MIN);
 537                 register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
 538                                                        tr, INT_MAX);
 539         } else {
 540                 unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
 541                                                     tr);
 542                 unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
 543                                                     tr);
 544         }
 545 }
 546
 547 static void
 548 event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
 549                     struct task_struct *prev, struct task_struct *next)
 550 {
 551         struct trace_array *tr = data;
 552         struct trace_pid_list *pid_list;
 553
 554         pid_list = rcu_dereference_sched(tr->filtered_pids);
 555
 556         this_cpu_write(tr->trace_buffer.data->ignore_pid,
 557                        trace_ignore_this_task(pid_list, prev) &&
 558                        trace_ignore_this_task(pid_list, next));
 559 }
 560
 561 static void
 562 event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
 563                     struct task_struct *prev, struct task_struct *next)
 564 {
 565         struct trace_array *tr = data;
 566         struct trace_pid_list *pid_list;
 567
 568         pid_list = rcu_dereference_sched(tr->filtered_pids);
 569
 570         this_cpu_write(tr->trace_buffer.data->ignore_pid,
 571                        trace_ignore_this_task(pid_list, next));
 572 }
 573
 574 static void
 575 event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
 576 {
 577         struct trace_array *tr = data;
 578         struct trace_pid_list *pid_list;
 579
 580         /* Nothing to do if we are already tracing */
 581         if (!this_cpu_read(tr->trace_buffer.data->ignore_pid))
 582                 return;
 583
 584         pid_list = rcu_dereference_sched(tr->filtered_pids);
 585
 586         this_cpu_write(tr->trace_buffer.data->ignore_pid,
 587                        trace_ignore_this_task(pid_list, task));
 588 }
 589
 590 static void
 591 event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
 592 {
 593         struct trace_array *tr = data;
 594         struct trace_pid_list *pid_list;
 595
 596         /* Nothing to do if we are not tracing */
 597         if (this_cpu_read(tr->trace_buffer.data->ignore_pid))
 598                 return;
 599
 600         pid_list = rcu_dereference_sched(tr->filtered_pids);
 601
 602         /* Set tracing if current is enabled */
 603         this_cpu_write(tr->trace_buffer.data->ignore_pid,
 604                        trace_ignore_this_task(pid_list, current));
 605 }
 606
 607 static void __ftrace_clear_event_pids(struct trace_array *tr)
 608 {
 609         struct trace_pid_list *pid_list;
 610         struct trace_event_file *file;
 611         int cpu;
 612
 613         pid_list = rcu_dereference_protected(tr->filtered_pids,
 614                                              lockdep_is_held(&event_mutex));
 615         if (!pid_list)
 616                 return;
 617
 618         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
 619         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
 620
 621         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
 622         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
 623
 624         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
 625         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
 626
 627         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
 628         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
 629
 630         list_for_each_entry(file, &tr->events, list) {
 631                 clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
 632         }
 633
 634         for_each_possible_cpu(cpu)
 635                 per_cpu_ptr(tr->trace_buffer.data, cpu)->ignore_pid = false;
 636
 637         rcu_assign_pointer(tr->filtered_pids, NULL);
 638
 639         /* Wait till all users are no longer using pid filtering */
 640         tracepoint_synchronize_unregister();
 641
 642         trace_free_pid_list(pid_list);
 643 }
 644
 645 static void ftrace_clear_event_pids(struct trace_array *tr)
 646 {
 647         mutex_lock(&event_mutex);
 648         __ftrace_clear_event_pids(tr);
 649         mutex_unlock(&event_mutex);
 650 }
 651
 652 static void __put_system(struct event_subsystem *system)
 653 {
 654         struct event_filter *filter = system->filter;
 655
 656         WARN_ON_ONCE(system_refcount(system) == 0);
 657         if (system_refcount_dec(system))
 658                 return;
 659
 660         list_del(&system->list);
 661
 662         if (filter) {
 663                 kfree(filter->filter_string);
 664                 kfree(filter);
 665         }
 666         kfree_const(system->name);
 667         kfree(system);
 668 }
 669
 670 static void __get_system(struct event_subsystem *system)
 671 {
 672         WARN_ON_ONCE(system_refcount(system) == 0);
 673         system_refcount_inc(system);
 674 }
 675
 676 static void __get_system_dir(struct trace_subsystem_dir *dir)
 677 {
 678         WARN_ON_ONCE(dir->ref_count == 0);
 679         dir->ref_count++;
 680         __get_system(dir->subsystem);
 681 }
 682
 683 static void __put_system_dir(struct trace_subsystem_dir *dir)
 684 {
 685         WARN_ON_ONCE(dir->ref_count == 0);
 686         /* If the subsystem is about to be freed, the dir must be too */
 687         WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
 688
 689         __put_system(dir->subsystem);
 690         if (!--dir->ref_count)
 691                 kfree(dir);
 692 }
 693
 694 static void put_system(struct trace_subsystem_dir *dir)
 695 {
 696         mutex_lock(&event_mutex);
 697         __put_system_dir(dir);
 698         mutex_unlock(&event_mutex);
 699 }
 700
 701 static void remove_subsystem(struct trace_subsystem_dir *dir)
 702 {
 703         if (!dir)
 704                 return;
 705
 706         if (!--dir->nr_events) {
 707                 tracefs_remove_recursive(dir->entry);
 708                 list_del(&dir->list);
 709                 __put_system_dir(dir);
 710         }
 711 }
 712
 713 static void remove_event_file_dir(struct trace_event_file *file)
 714 {
 715         struct dentry *dir = file->dir;
 716         struct dentry *child;
 717
 718         if (dir) {
 719                 spin_lock(&dir->d_lock);        /* probably unneeded */
 720                 list_for_each_entry(child, &dir->d_subdirs, d_child) {
 721                         if (d_really_is_positive(child))        /* probably unneeded */
 722                                 d_inode(child)->i_private = NULL;
 723                 }
 724                 spin_unlock(&dir->d_lock);
 725
 726                 tracefs_remove_recursive(dir);
 727         }
 728
 729         list_del(&file->list);
 730         remove_subsystem(file->system);
 731         free_event_filter(file->filter);
 732         kmem_cache_free(file_cachep, file);
 733 }
 734
 735 /*
 736  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
 737  */
 738 static int
 739 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
 740                               const char *sub, const char *event, int set)
 741 {
 742         struct trace_event_file *file;
 743         struct trace_event_call *call;
 744         const char *name;
 745         int ret = -EINVAL;
 746         int eret = 0;
 747
 748         list_for_each_entry(file, &tr->events, list) {
 749
 750                 call = file->event_call;
 751                 name = trace_event_name(call);
 752
 753                 if (!name || !call->class || !call->class->reg)
 754                         continue;
 755
 756                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
 757                         continue;
 758
 759                 if (match &&
 760                     strcmp(match, name) != 0 &&
 761                     strcmp(match, call->class->system) != 0)
 762                         continue;
 763
 764                 if (sub && strcmp(sub, call->class->system) != 0)
 765                         continue;
 766
 767                 if (event && strcmp(event, name) != 0)
 768                         continue;
 769
 770                 ret = ftrace_event_enable_disable(file, set);
 771
 772                 /*
 773                  * Save the first error and return that. Some events
 774                  * may still have been enabled, but let the user
 775                  * know that something went wrong.
 776                  */
 777                 if (ret && !eret)
 778                         eret = ret;
 779
 780                 ret = eret;
 781         }
 782
 783         return ret;
 784 }
 785
 786 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
 787                                   const char *sub, const char *event, int set)
 788 {
 789         int ret;
 790
 791         mutex_lock(&event_mutex);
 792         ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
 793         mutex_unlock(&event_mutex);
 794
 795         return ret;
 796 }
 797
 798 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
 799 {
 800         char *event = NULL, *sub = NULL, *match;
 801         int ret;
 802
 803         if (!tr)
 804                 return -ENOENT;
 805         /*
 806          * The buf format can be <subsystem>:<event-name>
 807          *  *:<event-name> means any event by that name.
 808          *  :<event-name> is the same.
 809          *
 810          *  <subsystem>:* means all events in that subsystem
 811          *  <subsystem>: means the same.
 812          *
 813          *  <name> (no ':') means all events in a subsystem with
 814          *  the name <name> or any event that matches <name>
 815          */
 816
 817         match = strsep(&buf, ":");
 818         if (buf) {
 819                 sub = match;
 820                 event = buf;
 821                 match = NULL;
 822
 823                 if (!strlen(sub) || strcmp(sub, "*") == 0)
 824                         sub = NULL;
 825                 if (!strlen(event) || strcmp(event, "*") == 0)
 826                         event = NULL;
 827         }
 828
 829         ret = __ftrace_set_clr_event(tr, match, sub, event, set);
 830
 831         /* Put back the colon to allow this to be called again */
 832         if (buf)
 833                 *(buf - 1) = ':';
 834
 835         return ret;
 836 }
 837
 838 /**
 839  * trace_set_clr_event - enable or disable an event
 840  * @system: system name to match (NULL for any system)
 841  * @event: event name to match (NULL for all events, within system)
 842  * @set: 1 to enable, 0 to disable
 843  *
 844  * This is a way for other parts of the kernel to enable or disable
 845  * event recording.
 846  *
 847  * Returns 0 on success, -EINVAL if the parameters do not match any
 848  * registered events.
 849  */
 850 int trace_set_clr_event(const char *system, const char *event, int set)
 851 {
 852         struct trace_array *tr = top_trace_array();
 853
 854         if (!tr)
 855                 return -ENODEV;
 856
 857         return __ftrace_set_clr_event(tr, NULL, system, event, set);
 858 }
 859 EXPORT_SYMBOL_GPL(trace_set_clr_event);
 860
 861 /* 128 should be much more than enough */
 862 #define EVENT_BUF_SIZE          127
 863
 864 static ssize_t
 865 ftrace_event_write(struct file *file, const char __user *ubuf,
 866                    size_t cnt, loff_t *ppos)
 867 {
 868         struct trace_parser parser;
 869         struct seq_file *m = file->private_data;
 870         struct trace_array *tr = m->private;
 871         ssize_t read, ret;
 872
 873         if (!cnt)
 874                 return 0;
 875
 876         ret = tracing_update_buffers();
 877         if (ret < 0)
 878                 return ret;
 879
 880         if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
 881                 return -ENOMEM;
 882
 883         read = trace_get_user(&parser, ubuf, cnt, ppos);
 884
 885         if (read >= 0 && trace_parser_loaded((&parser))) {
 886                 int set = 1;
 887
 888                 if (*parser.buffer == '!')
 889                         set = 0;
 890
 891                 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
 892                 if (ret)
 893                         goto out_put;
 894         }
 895
 896         ret = read;
 897
 898  out_put:
 899         trace_parser_put(&parser);
 900
 901         return ret;
 902 }
 903
 904 static void *
 905 t_next(struct seq_file *m, void *v, loff_t *pos)
 906 {
 907         struct trace_event_file *file = v;
 908         struct trace_event_call *call;
 909         struct trace_array *tr = m->private;
 910
 911         (*pos)++;
 912
 913         list_for_each_entry_continue(file, &tr->events, list) {
 914                 call = file->event_call;
 915                 /*
 916                  * The ftrace subsystem is for showing formats only.
 917                  * They can not be enabled or disabled via the event files.
 918                  */
 919                 if (call->class && call->class->reg &&
 920                     !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
 921                         return file;
 922         }
 923
 924         return NULL;
 925 }
 926
 927 static void *t_start(struct seq_file *m, loff_t *pos)
 928 {
 929         struct trace_event_file *file;
 930         struct trace_array *tr = m->private;
 931         loff_t l;
 932
 933         mutex_lock(&event_mutex);
 934
 935         file = list_entry(&tr->events, struct trace_event_file, list);
 936         for (l = 0; l <= *pos; ) {
 937                 file = t_next(m, file, &l);
 938                 if (!file)
 939                         break;
 940         }
 941         return file;
 942 }
 943
 944 static void *
 945 s_next(struct seq_file *m, void *v, loff_t *pos)
 946 {
 947         struct trace_event_file *file = v;
 948         struct trace_array *tr = m->private;
 949
 950         (*pos)++;
 951
 952         list_for_each_entry_continue(file, &tr->events, list) {
 953                 if (file->flags & EVENT_FILE_FL_ENABLED)
 954                         return file;
 955         }
 956
 957         return NULL;
 958 }
 959
 960 static void *s_start(struct seq_file *m, loff_t *pos)
 961 {
 962         struct trace_event_file *file;
 963         struct trace_array *tr = m->private;
 964         loff_t l;
 965
 966         mutex_lock(&event_mutex);
 967
 968         file = list_entry(&tr->events, struct trace_event_file, list);
 969         for (l = 0; l <= *pos; ) {
 970                 file = s_next(m, file, &l);
 971                 if (!file)
 972                         break;
 973         }
 974         return file;
 975 }
 976
 977 static int t_show(struct seq_file *m, void *v)
 978 {
 979         struct trace_event_file *file = v;
 980         struct trace_event_call *call = file->event_call;
 981
 982         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
 983                 seq_printf(m, "%s:", call->class->system);
 984         seq_printf(m, "%s\n", trace_event_name(call));
 985
 986         return 0;
 987 }
 988
 989 static void t_stop(struct seq_file *m, void *p)
 990 {
 991         mutex_unlock(&event_mutex);
 992 }
 993
 994 static void *
 995 p_next(struct seq_file *m, void *v, loff_t *pos)
 996 {
 997         struct trace_array *tr = m->private;
 998         struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids);
 999
1000         return trace_pid_next(pid_list, v, pos);
1001 }
1002
1003 static void *p_start(struct seq_file *m, loff_t *pos)
1004         __acquires(RCU)
1005 {
1006         struct trace_pid_list *pid_list;
1007         struct trace_array *tr = m->private;
1008
1009         /*
1010          * Grab the mutex, to keep calls to p_next() having the same
1011          * tr->filtered_pids as p_start() has.
1012          * If we just passed the tr->filtered_pids around, then RCU would
1013          * have been enough, but doing that makes things more complex.
1014          */
1015         mutex_lock(&event_mutex);
1016         rcu_read_lock_sched();
1017
1018         pid_list = rcu_dereference_sched(tr->filtered_pids);
1019
1020         if (!pid_list)
1021                 return NULL;
1022
1023         return trace_pid_start(pid_list, pos);
1024 }
1025
1026 static void p_stop(struct seq_file *m, void *p)
1027         __releases(RCU)
1028 {
1029         rcu_read_unlock_sched();
1030         mutex_unlock(&event_mutex);
1031 }
1032
1033 static ssize_t
1034 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1035                   loff_t *ppos)
1036 {
1037         struct trace_event_file *file;
1038         unsigned long flags;
1039         char buf[4] = "0";
1040
1041         mutex_lock(&event_mutex);
1042         file = event_file_data(filp);
1043         if (likely(file))
1044                 flags = file->flags;
1045         mutex_unlock(&event_mutex);
1046
1047         if (!file)
1048                 return -ENODEV;
1049
1050         if (flags & EVENT_FILE_FL_ENABLED &&
1051             !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1052                 strcpy(buf, "1");
1053
1054         if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1055             flags & EVENT_FILE_FL_SOFT_MODE)
1056                 strcat(buf, "*");
1057
1058         strcat(buf, "\n");
1059
1060         return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1061 }
1062
1063 static ssize_t
1064 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1065                    loff_t *ppos)
1066 {
1067         struct trace_event_file *file;
1068         unsigned long val;
1069         int ret;
1070
1071         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1072         if (ret)
1073                 return ret;
1074
1075         ret = tracing_update_buffers();
1076         if (ret < 0)
1077                 return ret;
1078
1079         switch (val) {
1080         case 0:
1081         case 1:
1082                 ret = -ENODEV;
1083                 mutex_lock(&event_mutex);
1084                 file = event_file_data(filp);
1085                 if (likely(file))
1086                         ret = ftrace_event_enable_disable(file, val);
1087                 mutex_unlock(&event_mutex);
1088                 break;
1089
1090         default:
1091                 return -EINVAL;
1092         }
1093
1094         *ppos += cnt;
1095
1096         return ret ? ret : cnt;
1097 }
1098
1099 static ssize_t
1100 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1101                    loff_t *ppos)
1102 {
1103         const char set_to_char[4] = { '?', '0', '1', 'X' };
1104         struct trace_subsystem_dir *dir = filp->private_data;
1105         struct event_subsystem *system = dir->subsystem;
1106         struct trace_event_call *call;
1107         struct trace_event_file *file;
1108         struct trace_array *tr = dir->tr;
1109         char buf[2];
1110         int set = 0;
1111         int ret;
1112
1113         mutex_lock(&event_mutex);
1114         list_for_each_entry(file, &tr->events, list) {
1115                 call = file->event_call;
1116                 if ((call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
1117                     !trace_event_name(call) || !call->class || !call->class->reg)
1118                         continue;
1119
1120                 if (system && strcmp(call->class->system, system->name) != 0)
1121                         continue;
1122
1123                 /*
1124                  * We need to find out if all the events are set
1125                  * or if all events or cleared, or if we have
1126                  * a mixture.
1127                  */
1128                 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1129
1130                 /*
1131                  * If we have a mixture, no need to look further.
1132                  */
1133                 if (set == 3)
1134                         break;
1135         }
1136         mutex_unlock(&event_mutex);
1137
1138         buf[0] = set_to_char[set];
1139         buf[1] = '\n';
1140
1141         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1142
1143         return ret;
1144 }
1145
1146 static ssize_t
1147 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1148                     loff_t *ppos)
1149 {
1150         struct trace_subsystem_dir *dir = filp->private_data;
1151         struct event_subsystem *system = dir->subsystem;
1152         const char *name = NULL;
1153         unsigned long val;
1154         ssize_t ret;
1155
1156         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1157         if (ret)
1158                 return ret;
1159
1160         ret = tracing_update_buffers();
1161         if (ret < 0)
1162                 return ret;
1163
1164         if (val != 0 && val != 1)
1165                 return -EINVAL;
1166
1167         /*
1168          * Opening of "enable" adds a ref count to system,
1169          * so the name is safe to use.
1170          */
1171         if (system)
1172                 name = system->name;
1173
1174         ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1175         if (ret)
1176                 goto out;
1177
1178         ret = cnt;
1179
1180 out:
1181         *ppos += cnt;
1182
1183         return ret;
1184 }
1185
1186 enum {
1187         FORMAT_HEADER           = 1,
1188         FORMAT_FIELD_SEPERATOR  = 2,
1189         FORMAT_PRINTFMT         = 3,
1190 };
1191
1192 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1193 {
1194         struct trace_event_call *call = event_file_data(m->private);
1195         struct list_head *common_head = &ftrace_common_fields;
1196         struct list_head *head = trace_get_fields(call);
1197         struct list_head *node = v;
1198
1199         (*pos)++;
1200
1201         switch ((unsigned long)v) {
1202         case FORMAT_HEADER:
1203                 node = common_head;
1204                 break;
1205
1206         case FORMAT_FIELD_SEPERATOR:
1207                 node = head;
1208                 break;
1209
1210         case FORMAT_PRINTFMT:
1211                 /* all done */
1212                 return NULL;
1213         }
1214
1215         node = node->prev;
1216         if (node == common_head)
1217                 return (void *)FORMAT_FIELD_SEPERATOR;
1218         else if (node == head)
1219                 return (void *)FORMAT_PRINTFMT;
1220         else
1221                 return node;
1222 }
1223
1224 static int f_show(struct seq_file *m, void *v)
1225 {
1226         struct trace_event_call *call = event_file_data(m->private);
1227         struct ftrace_event_field *field;
1228         const char *array_descriptor;
1229
1230         switch ((unsigned long)v) {
1231         case FORMAT_HEADER:
1232                 seq_printf(m, "name: %s\n", trace_event_name(call));
1233                 seq_printf(m, "ID: %d\n", call->event.type);
1234                 seq_puts(m, "format:\n");
1235                 return 0;
1236
1237         case FORMAT_FIELD_SEPERATOR:
1238                 seq_putc(m, '\n');
1239                 return 0;
1240
1241         case FORMAT_PRINTFMT:
1242                 seq_printf(m, "\nprint fmt: %s\n",
1243                            call->print_fmt);
1244                 return 0;
1245         }
1246
1247         field = list_entry(v, struct ftrace_event_field, link);
1248         /*
1249          * Smartly shows the array type(except dynamic array).
1250          * Normal:
1251          *      field:TYPE VAR
1252          * If TYPE := TYPE[LEN], it is shown:
1253          *      field:TYPE VAR[LEN]
1254          */
1255         array_descriptor = strchr(field->type, '[');
1256
1257         if (!strncmp(field->type, "__data_loc", 10))
1258                 array_descriptor = NULL;
1259
1260         if (!array_descriptor)
1261                 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1262                            field->type, field->name, field->offset,
1263                            field->size, !!field->is_signed);
1264         else
1265                 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1266                            (int)(array_descriptor - field->type),
1267                            field->type, field->name,
1268                            array_descriptor, field->offset,
1269                            field->size, !!field->is_signed);
1270
1271         return 0;
1272 }
1273
1274 static void *f_start(struct seq_file *m, loff_t *pos)
1275 {
1276         void *p = (void *)FORMAT_HEADER;
1277         loff_t l = 0;
1278
1279         /* ->stop() is called even if ->start() fails */
1280         mutex_lock(&event_mutex);
1281         if (!event_file_data(m->private))
1282                 return ERR_PTR(-ENODEV);
1283
1284         while (l < *pos && p)
1285                 p = f_next(m, p, &l);
1286
1287         return p;
1288 }
1289
1290 static void f_stop(struct seq_file *m, void *p)
1291 {
1292         mutex_unlock(&event_mutex);
1293 }
1294
1295 static const struct seq_operations trace_format_seq_ops = {
1296         .start          = f_start,
1297         .next           = f_next,
1298         .stop           = f_stop,
1299         .show           = f_show,
1300 };
1301
1302 static int trace_format_open(struct inode *inode, struct file *file)
1303 {
1304         struct seq_file *m;
1305         int ret;
1306
1307         ret = seq_open(file, &trace_format_seq_ops);
1308         if (ret < 0)
1309                 return ret;
1310
1311         m = file->private_data;
1312         m->private = file;
1313
1314         return 0;
1315 }
1316
1317 static ssize_t
1318 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1319 {
1320         int id = (long)event_file_data(filp);
1321         char buf[32];
1322         int len;
1323
1324         if (unlikely(!id))
1325                 return -ENODEV;
1326
1327         len = sprintf(buf, "%d\n", id);
1328
1329         return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1330 }
1331
1332 static ssize_t
1333 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1334                   loff_t *ppos)
1335 {
1336         struct trace_event_file *file;
1337         struct trace_seq *s;
1338         int r = -ENODEV;
1339
1340         if (*ppos)
1341                 return 0;
1342
1343         s = kmalloc(sizeof(*s), GFP_KERNEL);
1344
1345         if (!s)
1346                 return -ENOMEM;
1347
1348         trace_seq_init(s);
1349
1350         mutex_lock(&event_mutex);
1351         file = event_file_data(filp);
1352         if (file)
1353                 print_event_filter(file, s);
1354         mutex_unlock(&event_mutex);
1355
1356         if (file)
1357                 r = simple_read_from_buffer(ubuf, cnt, ppos,
1358                                             s->buffer, trace_seq_used(s));
1359
1360         kfree(s);
1361
1362         return r;
1363 }
1364
1365 static ssize_t
1366 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1367                    loff_t *ppos)
1368 {
1369         struct trace_event_file *file;
1370         char *buf;
1371         int err = -ENODEV;
1372
1373         if (cnt >= PAGE_SIZE)
1374                 return -EINVAL;
1375
1376         buf = memdup_user_nul(ubuf, cnt);
1377         if (IS_ERR(buf))
1378                 return PTR_ERR(buf);
1379
1380         mutex_lock(&event_mutex);
1381         file = event_file_data(filp);
1382         if (file)
1383                 err = apply_event_filter(file, buf);
1384         mutex_unlock(&event_mutex);
1385
1386         kfree(buf);
1387         if (err < 0)
1388                 return err;
1389
1390         *ppos += cnt;
1391
1392         return cnt;
1393 }
1394
1395 static LIST_HEAD(event_subsystems);
1396
1397 static int subsystem_open(struct inode *inode, struct file *filp)
1398 {
1399         struct event_subsystem *system = NULL;
1400         struct trace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1401         struct trace_array *tr;
1402         int ret;
1403
1404         if (tracing_is_disabled())
1405                 return -ENODEV;
1406
1407         /* Make sure the system still exists */
1408         mutex_lock(&event_mutex);
1409         mutex_lock(&trace_types_lock);
1410         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1411                 list_for_each_entry(dir, &tr->systems, list) {
1412                         if (dir == inode->i_private) {
1413                                 /* Don't open systems with no events */
1414                                 if (dir->nr_events) {
1415                                         __get_system_dir(dir);
1416                                         system = dir->subsystem;
1417                                 }
1418                                 goto exit_loop;
1419                         }
1420                 }
1421         }
1422  exit_loop:
1423         mutex_unlock(&trace_types_lock);
1424         mutex_unlock(&event_mutex);
1425
1426         if (!system)
1427                 return -ENODEV;
1428
1429         /* Some versions of gcc think dir can be uninitialized here */
1430         WARN_ON(!dir);
1431
1432         /* Still need to increment the ref count of the system */
1433         if (trace_array_get(tr) < 0) {
1434                 put_system(dir);
1435                 return -ENODEV;
1436         }
1437
1438         ret = tracing_open_generic(inode, filp);
1439         if (ret < 0) {
1440                 trace_array_put(tr);
1441                 put_system(dir);
1442         }
1443
1444         return ret;
1445 }
1446
1447 static int system_tr_open(struct inode *inode, struct file *filp)
1448 {
1449         struct trace_subsystem_dir *dir;
1450         struct trace_array *tr = inode->i_private;
1451         int ret;
1452
1453         if (tracing_is_disabled())
1454                 return -ENODEV;
1455
1456         if (trace_array_get(tr) < 0)
1457                 return -ENODEV;
1458
1459         /* Make a temporary dir that has no system but points to tr */
1460         dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1461         if (!dir) {
1462                 trace_array_put(tr);
1463                 return -ENOMEM;
1464         }
1465
1466         dir->tr = tr;
1467
1468         ret = tracing_open_generic(inode, filp);
1469         if (ret < 0) {
1470                 trace_array_put(tr);
1471                 kfree(dir);
1472                 return ret;
1473         }
1474
1475         filp->private_data = dir;
1476
1477         return 0;
1478 }
1479
1480 static int subsystem_release(struct inode *inode, struct file *file)
1481 {
1482         struct trace_subsystem_dir *dir = file->private_data;
1483
1484         trace_array_put(dir->tr);
1485
1486         /*
1487          * If dir->subsystem is NULL, then this is a temporary
1488          * descriptor that was made for a trace_array to enable
1489          * all subsystems.
1490          */
1491         if (dir->subsystem)
1492                 put_system(dir);
1493         else
1494                 kfree(dir);
1495
1496         return 0;
1497 }
1498
1499 static ssize_t
1500 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1501                       loff_t *ppos)
1502 {
1503         struct trace_subsystem_dir *dir = filp->private_data;
1504         struct event_subsystem *system = dir->subsystem;
1505         struct trace_seq *s;
1506         int r;
1507
1508         if (*ppos)
1509                 return 0;
1510
1511         s = kmalloc(sizeof(*s), GFP_KERNEL);
1512         if (!s)
1513                 return -ENOMEM;
1514
1515         trace_seq_init(s);
1516
1517         print_subsystem_event_filter(system, s);
1518         r = simple_read_from_buffer(ubuf, cnt, ppos,
1519                                     s->buffer, trace_seq_used(s));
1520
1521         kfree(s);
1522
1523         return r;
1524 }
1525
1526 static ssize_t
1527 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1528                        loff_t *ppos)
1529 {
1530         struct trace_subsystem_dir *dir = filp->private_data;
1531         char *buf;
1532         int err;
1533
1534         if (cnt >= PAGE_SIZE)
1535                 return -EINVAL;
1536
1537         buf = memdup_user_nul(ubuf, cnt);
1538         if (IS_ERR(buf))
1539                 return PTR_ERR(buf);
1540
1541         err = apply_subsystem_event_filter(dir, buf);
1542         kfree(buf);
1543         if (err < 0)
1544                 return err;
1545
1546         *ppos += cnt;
1547
1548         return cnt;
1549 }
1550
1551 static ssize_t
1552 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1553 {
1554         int (*func)(struct trace_seq *s) = filp->private_data;
1555         struct trace_seq *s;
1556         int r;
1557
1558         if (*ppos)
1559                 return 0;
1560
1561         s = kmalloc(sizeof(*s), GFP_KERNEL);
1562         if (!s)
1563                 return -ENOMEM;
1564
1565         trace_seq_init(s);
1566
1567         func(s);
1568         r = simple_read_from_buffer(ubuf, cnt, ppos,
1569                                     s->buffer, trace_seq_used(s));
1570
1571         kfree(s);
1572
1573         return r;
1574 }
1575
1576 static void ignore_task_cpu(void *data)
1577 {
1578         struct trace_array *tr = data;
1579         struct trace_pid_list *pid_list;
1580
1581         /*
1582          * This function is called by on_each_cpu() while the
1583          * event_mutex is held.
1584          */
1585         pid_list = rcu_dereference_protected(tr->filtered_pids,
1586                                              mutex_is_locked(&event_mutex));
1587
1588         this_cpu_write(tr->trace_buffer.data->ignore_pid,
1589                        trace_ignore_this_task(pid_list, current));
1590 }
1591
1592 static ssize_t
1593 ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
1594                        size_t cnt, loff_t *ppos)
1595 {
1596         struct seq_file *m = filp->private_data;
1597         struct trace_array *tr = m->private;
1598         struct trace_pid_list *filtered_pids = NULL;
1599         struct trace_pid_list *pid_list;
1600         struct trace_event_file *file;
1601         ssize_t ret;
1602
1603         if (!cnt)
1604                 return 0;
1605
1606         ret = tracing_update_buffers();
1607         if (ret < 0)
1608                 return ret;
1609
1610         mutex_lock(&event_mutex);
1611
1612         filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1613                                              lockdep_is_held(&event_mutex));
1614
1615         ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
1616         if (ret < 0)
1617                 goto out;
1618
1619         rcu_assign_pointer(tr->filtered_pids, pid_list);
1620
1621         list_for_each_entry(file, &tr->events, list) {
1622                 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
1623         }
1624
1625         if (filtered_pids) {
1626                 tracepoint_synchronize_unregister();
1627                 trace_free_pid_list(filtered_pids);
1628         } else if (pid_list) {
1629                 /*
1630                  * Register a probe that is called before all other probes
1631                  * to set ignore_pid if next or prev do not match.
1632                  * Register a probe this is called after all other probes
1633                  * to only keep ignore_pid set if next pid matches.
1634                  */
1635                 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1636                                                  tr, INT_MAX);
1637                 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1638                                                  tr, 0);
1639
1640                 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1641                                                  tr, INT_MAX);
1642                 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1643                                                  tr, 0);
1644
1645                 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1646                                                      tr, INT_MAX);
1647                 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1648                                                      tr, 0);
1649
1650                 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1651                                                  tr, INT_MAX);
1652                 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1653                                                  tr, 0);
1654         }
1655
1656         /*
1657          * Ignoring of pids is done at task switch. But we have to
1658          * check for those tasks that are currently running.
1659          * Always do this in case a pid was appended or removed.
1660          */
1661         on_each_cpu(ignore_task_cpu, tr, 1);
1662
1663  out:
1664         mutex_unlock(&event_mutex);
1665
1666         if (ret > 0)
1667                 *ppos += ret;
1668
1669         return ret;
1670 }
1671
1672 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1673 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1674 static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
1675 static int ftrace_event_release(struct inode *inode, struct file *file);
1676
1677 static const struct seq_operations show_event_seq_ops = {
1678         .start = t_start,
1679         .next = t_next,
1680         .show = t_show,
1681         .stop = t_stop,
1682 };
1683
1684 static const struct seq_operations show_set_event_seq_ops = {
1685         .start = s_start,
1686         .next = s_next,
1687         .show = t_show,
1688         .stop = t_stop,
1689 };
1690
1691 static const struct seq_operations show_set_pid_seq_ops = {
1692         .start = p_start,
1693         .next = p_next,
1694         .show = trace_pid_show,
1695         .stop = p_stop,
1696 };
1697
1698 static const struct file_operations ftrace_avail_fops = {
1699         .open = ftrace_event_avail_open,
1700         .read = seq_read,
1701         .llseek = seq_lseek,
1702         .release = seq_release,
1703 };
1704
1705 static const struct file_operations ftrace_set_event_fops = {
1706         .open = ftrace_event_set_open,
1707         .read = seq_read,
1708         .write = ftrace_event_write,
1709         .llseek = seq_lseek,
1710         .release = ftrace_event_release,
1711 };
1712
1713 static const struct file_operations ftrace_set_event_pid_fops = {
1714         .open = ftrace_event_set_pid_open,
1715         .read = seq_read,
1716         .write = ftrace_event_pid_write,
1717         .llseek = seq_lseek,
1718         .release = ftrace_event_release,
1719 };
1720
1721 static const struct file_operations ftrace_enable_fops = {
1722         .open = tracing_open_generic,
1723         .read = event_enable_read,
1724         .write = event_enable_write,
1725         .llseek = default_llseek,
1726 };
1727
1728 static const struct file_operations ftrace_event_format_fops = {
1729         .open = trace_format_open,
1730         .read = seq_read,
1731         .llseek = seq_lseek,
1732         .release = seq_release,
1733 };
1734
1735 static const struct file_operations ftrace_event_id_fops = {
1736         .read = event_id_read,
1737         .llseek = default_llseek,
1738 };
1739
1740 static const struct file_operations ftrace_event_filter_fops = {
1741         .open = tracing_open_generic,
1742         .read = event_filter_read,
1743         .write = event_filter_write,
1744         .llseek = default_llseek,
1745 };
1746
1747 static const struct file_operations ftrace_subsystem_filter_fops = {
1748         .open = subsystem_open,
1749         .read = subsystem_filter_read,
1750         .write = subsystem_filter_write,
1751         .llseek = default_llseek,
1752         .release = subsystem_release,
1753 };
1754
1755 static const struct file_operations ftrace_system_enable_fops = {
1756         .open = subsystem_open,
1757         .read = system_enable_read,
1758         .write = system_enable_write,
1759         .llseek = default_llseek,
1760         .release = subsystem_release,
1761 };
1762
1763 static const struct file_operations ftrace_tr_enable_fops = {
1764         .open = system_tr_open,
1765         .read = system_enable_read,
1766         .write = system_enable_write,
1767         .llseek = default_llseek,
1768         .release = subsystem_release,
1769 };
1770
1771 static const struct file_operations ftrace_show_header_fops = {
1772         .open = tracing_open_generic,
1773         .read = show_header,
1774         .llseek = default_llseek,
1775 };
1776
1777 static int
1778 ftrace_event_open(struct inode *inode, struct file *file,
1779                   const struct seq_operations *seq_ops)
1780 {
1781         struct seq_file *m;
1782         int ret;
1783
1784         ret = seq_open(file, seq_ops);
1785         if (ret < 0)
1786                 return ret;
1787         m = file->private_data;
1788         /* copy tr over to seq ops */
1789         m->private = inode->i_private;
1790
1791         return ret;
1792 }
1793
1794 static int ftrace_event_release(struct inode *inode, struct file *file)
1795 {
1796         struct trace_array *tr = inode->i_private;
1797
1798         trace_array_put(tr);
1799
1800         return seq_release(inode, file);
1801 }
1802
1803 static int
1804 ftrace_event_avail_open(struct inode *inode, struct file *file)
1805 {
1806         const struct seq_operations *seq_ops = &show_event_seq_ops;
1807
1808         return ftrace_event_open(inode, file, seq_ops);
1809 }
1810
1811 static int
1812 ftrace_event_set_open(struct inode *inode, struct file *file)
1813 {
1814         const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1815         struct trace_array *tr = inode->i_private;
1816         int ret;
1817
1818         if (trace_array_get(tr) < 0)
1819                 return -ENODEV;
1820
1821         if ((file->f_mode & FMODE_WRITE) &&
1822             (file->f_flags & O_TRUNC))
1823                 ftrace_clear_events(tr);
1824
1825         ret = ftrace_event_open(inode, file, seq_ops);
1826         if (ret < 0)
1827                 trace_array_put(tr);
1828         return ret;
1829 }
1830
1831 static int
1832 ftrace_event_set_pid_open(struct inode *inode, struct file *file)
1833 {
1834         const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
1835         struct trace_array *tr = inode->i_private;
1836         int ret;
1837
1838         if (trace_array_get(tr) < 0)
1839                 return -ENODEV;
1840
1841         if ((file->f_mode & FMODE_WRITE) &&
1842             (file->f_flags & O_TRUNC))
1843                 ftrace_clear_event_pids(tr);
1844
1845         ret = ftrace_event_open(inode, file, seq_ops);
1846         if (ret < 0)
1847                 trace_array_put(tr);
1848         return ret;
1849 }
1850
1851 static struct event_subsystem *
1852 create_new_subsystem(const char *name)
1853 {
1854         struct event_subsystem *system;
1855
1856         /* need to create new entry */
1857         system = kmalloc(sizeof(*system), GFP_KERNEL);
1858         if (!system)
1859                 return NULL;
1860
1861         system->ref_count = 1;
1862
1863         /* Only allocate if dynamic (kprobes and modules) */
1864         system->name = kstrdup_const(name, GFP_KERNEL);
1865         if (!system->name)
1866                 goto out_free;
1867
1868         system->filter = NULL;
1869
1870         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1871         if (!system->filter)
1872                 goto out_free;
1873
1874         list_add(&system->list, &event_subsystems);
1875
1876         return system;
1877
1878  out_free:
1879         kfree_const(system->name);
1880         kfree(system);
1881         return NULL;
1882 }
1883
1884 static struct dentry *
1885 event_subsystem_dir(struct trace_array *tr, const char *name,
1886                     struct trace_event_file *file, struct dentry *parent)
1887 {
1888         struct trace_subsystem_dir *dir;
1889         struct event_subsystem *system;
1890         struct dentry *entry;
1891
1892         /* First see if we did not already create this dir */
1893         list_for_each_entry(dir, &tr->systems, list) {
1894                 system = dir->subsystem;
1895                 if (strcmp(system->name, name) == 0) {
1896                         dir->nr_events++;
1897                         file->system = dir;
1898                         return dir->entry;
1899                 }
1900         }
1901
1902         /* Now see if the system itself exists. */
1903         list_for_each_entry(system, &event_subsystems, list) {
1904                 if (strcmp(system->name, name) == 0)
1905                         break;
1906         }
1907         /* Reset system variable when not found */
1908         if (&system->list == &event_subsystems)
1909                 system = NULL;
1910
1911         dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1912         if (!dir)
1913                 goto out_fail;
1914
1915         if (!system) {
1916                 system = create_new_subsystem(name);
1917                 if (!system)
1918                         goto out_free;
1919         } else
1920                 __get_system(system);
1921
1922         dir->entry = tracefs_create_dir(name, parent);
1923         if (!dir->entry) {
1924                 pr_warn("Failed to create system directory %s\n", name);
1925                 __put_system(system);
1926                 goto out_free;
1927         }
1928
1929         dir->tr = tr;
1930         dir->ref_count = 1;
1931         dir->nr_events = 1;
1932         dir->subsystem = system;
1933         file->system = dir;
1934
1935         entry = tracefs_create_file("filter", 0644, dir->entry, dir,
1936                                     &ftrace_subsystem_filter_fops);
1937         if (!entry) {
1938                 kfree(system->filter);
1939                 system->filter = NULL;
1940                 pr_warn("Could not create tracefs '%s/filter' entry\n", name);
1941         }
1942
1943         trace_create_file("enable", 0644, dir->entry, dir,
1944                           &ftrace_system_enable_fops);
1945
1946         list_add(&dir->list, &tr->systems);
1947
1948         return dir->entry;
1949
1950  out_free:
1951         kfree(dir);
1952  out_fail:
1953         /* Only print this message if failed on memory allocation */
1954         if (!dir || !system)
1955                 pr_warn("No memory to create event subsystem %s\n", name);
1956         return NULL;
1957 }
1958
1959 static int
1960 event_create_dir(struct dentry *parent, struct trace_event_file *file)
1961 {
1962         struct trace_event_call *call = file->event_call;
1963         struct trace_array *tr = file->tr;
1964         struct list_head *head;
1965         struct dentry *d_events;
1966         const char *name;
1967         int ret;
1968
1969         /*
1970          * If the trace point header did not define TRACE_SYSTEM
1971          * then the system would be called "TRACE_SYSTEM".
1972          */
1973         if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1974                 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1975                 if (!d_events)
1976                         return -ENOMEM;
1977         } else
1978                 d_events = parent;
1979
1980         name = trace_event_name(call);
1981         file->dir = tracefs_create_dir(name, d_events);
1982         if (!file->dir) {
1983                 pr_warn("Could not create tracefs '%s' directory\n", name);
1984                 return -1;
1985         }
1986
1987         if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1988                 trace_create_file("enable", 0644, file->dir, file,
1989                                   &ftrace_enable_fops);
1990
1991 #ifdef CONFIG_PERF_EVENTS
1992         if (call->event.type && call->class->reg)
1993                 trace_create_file("id", 0444, file->dir,
1994                                   (void *)(long)call->event.type,
1995                                   &ftrace_event_id_fops);
1996 #endif
1997
1998         /*
1999          * Other events may have the same class. Only update
2000          * the fields if they are not already defined.
2001          */
2002         head = trace_get_fields(call);
2003         if (list_empty(head)) {
2004                 ret = call->class->define_fields(call);
2005                 if (ret < 0) {
2006                         pr_warn("Could not initialize trace point events/%s\n",
2007                                 name);
2008                         return -1;
2009                 }
2010         }
2011
2012         /*
2013          * Only event directories that can be enabled should have
2014          * triggers or filters.
2015          */
2016         if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
2017                 trace_create_file("filter", 0644, file->dir, file,
2018                                   &ftrace_event_filter_fops);
2019
2020                 trace_create_file("trigger", 0644, file->dir, file,
2021                                   &event_trigger_fops);
2022         }
2023
2024 #ifdef CONFIG_HIST_TRIGGERS
2025         trace_create_file("hist", 0444, file->dir, file,
2026                           &event_hist_fops);
2027 #endif
2028         trace_create_file("format", 0444, file->dir, call,
2029                           &ftrace_event_format_fops);
2030
2031         return 0;
2032 }
2033
2034 static void remove_event_from_tracers(struct trace_event_call *call)
2035 {
2036         struct trace_event_file *file;
2037         struct trace_array *tr;
2038
2039         do_for_each_event_file_safe(tr, file) {
2040                 if (file->event_call != call)
2041                         continue;
2042
2043                 remove_event_file_dir(file);
2044                 /*
2045                  * The do_for_each_event_file_safe() is
2046                  * a double loop. After finding the call for this
2047                  * trace_array, we use break to jump to the next
2048                  * trace_array.
2049                  */
2050                 break;
2051         } while_for_each_event_file();
2052 }
2053
2054 static void event_remove(struct trace_event_call *call)
2055 {
2056         struct trace_array *tr;
2057         struct trace_event_file *file;
2058
2059         do_for_each_event_file(tr, file) {
2060                 if (file->event_call != call)
2061                         continue;
2062
2063                 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2064                         tr->clear_trace = true;
2065
2066                 ftrace_event_enable_disable(file, 0);
2067                 /*
2068                  * The do_for_each_event_file() is
2069                  * a double loop. After finding the call for this
2070                  * trace_array, we use break to jump to the next
2071                  * trace_array.
2072                  */
2073                 break;
2074         } while_for_each_event_file();
2075
2076         if (call->event.funcs)
2077                 __unregister_trace_event(&call->event);
2078         remove_event_from_tracers(call);
2079         list_del(&call->list);
2080 }
2081
2082 static int event_init(struct trace_event_call *call)
2083 {
2084         int ret = 0;
2085         const char *name;
2086
2087         name = trace_event_name(call);
2088         if (WARN_ON(!name))
2089                 return -EINVAL;
2090
2091         if (call->class->raw_init) {
2092                 ret = call->class->raw_init(call);
2093                 if (ret < 0 && ret != -ENOSYS)
2094                         pr_warn("Could not initialize trace events/%s\n", name);
2095         }
2096
2097         return ret;
2098 }
2099
2100 static int
2101 __register_event(struct trace_event_call *call, struct module *mod)
2102 {
2103         int ret;
2104
2105         ret = event_init(call);
2106         if (ret < 0)
2107                 return ret;
2108
2109         list_add(&call->list, &ftrace_events);
2110         call->mod = mod;
2111
2112         return 0;
2113 }
2114
2115 static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2116 {
2117         int rlen;
2118         int elen;
2119
2120         /* Find the length of the eval value as a string */
2121         elen = snprintf(ptr, 0, "%ld", map->eval_value);
2122         /* Make sure there's enough room to replace the string with the value */
2123         if (len < elen)
2124                 return NULL;
2125
2126         snprintf(ptr, elen + 1, "%ld", map->eval_value);
2127
2128         /* Get the rest of the string of ptr */
2129         rlen = strlen(ptr + len);
2130         memmove(ptr + elen, ptr + len, rlen);
2131         /* Make sure we end the new string */
2132         ptr[elen + rlen] = 0;
2133
2134         return ptr + elen;
2135 }
2136
2137 static void update_event_printk(struct trace_event_call *call,
2138                                 struct trace_eval_map *map)
2139 {
2140         char *ptr;
2141         int quote = 0;
2142         int len = strlen(map->eval_string);
2143
2144         for (ptr = call->print_fmt; *ptr; ptr++) {
2145                 if (*ptr == '\\') {
2146                         ptr++;
2147                         /* paranoid */
2148                         if (!*ptr)
2149                                 break;
2150                         continue;
2151                 }
2152                 if (*ptr == '"') {
2153                         quote ^= 1;
2154                         continue;
2155                 }
2156                 if (quote)
2157                         continue;
2158                 if (isdigit(*ptr)) {
2159                         /* skip numbers */
2160                         do {
2161                                 ptr++;
2162                                 /* Check for alpha chars like ULL */
2163                         } while (isalnum(*ptr));
2164                         if (!*ptr)
2165                                 break;
2166                         /*
2167                          * A number must have some kind of delimiter after
2168                          * it, and we can ignore that too.
2169                          */
2170                         continue;
2171                 }
2172                 if (isalpha(*ptr) || *ptr == '_') {
2173                         if (strncmp(map->eval_string, ptr, len) == 0 &&
2174                             !isalnum(ptr[len]) && ptr[len] != '_') {
2175                                 ptr = eval_replace(ptr, map, len);
2176                                 /* enum/sizeof string smaller than value */
2177                                 if (WARN_ON_ONCE(!ptr))
2178                                         return;
2179                                 /*
2180                                  * No need to decrement here, as eval_replace()
2181                                  * returns the pointer to the character passed
2182                                  * the eval, and two evals can not be placed
2183                                  * back to back without something in between.
2184                                  * We can skip that something in between.
2185                                  */
2186                                 continue;
2187                         }
2188                 skip_more:
2189                         do {
2190                                 ptr++;
2191                         } while (isalnum(*ptr) || *ptr == '_');
2192                         if (!*ptr)
2193                                 break;
2194                         /*
2195                          * If what comes after this variable is a '.' or
2196                          * '->' then we can continue to ignore that string.
2197                          */
2198                         if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2199                                 ptr += *ptr == '.' ? 1 : 2;
2200                                 if (!*ptr)
2201                                         break;
2202                                 goto skip_more;
2203                         }
2204                         /*
2205                          * Once again, we can skip the delimiter that came
2206                          * after the string.
2207                          */
2208                         continue;
2209                 }
2210         }
2211 }
2212
2213 void trace_event_eval_update(struct trace_eval_map **map, int len)
2214 {
2215         struct trace_event_call *call, *p;
2216         const char *last_system = NULL;
2217         bool first = false;
2218         int last_i;
2219         int i;
2220
2221         down_write(&trace_event_sem);
2222         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2223                 /* events are usually grouped together with systems */
2224                 if (!last_system || call->class->system != last_system) {
2225                         first = true;
2226                         last_i = 0;
2227                         last_system = call->class->system;
2228                 }
2229
2230                 /*
2231                  * Since calls are grouped by systems, the likelyhood that the
2232                  * next call in the iteration belongs to the same system as the
2233                  * previous call is high. As an optimization, we skip seaching
2234                  * for a map[] that matches the call's system if the last call
2235                  * was from the same system. That's what last_i is for. If the
2236                  * call has the same system as the previous call, then last_i
2237                  * will be the index of the first map[] that has a matching
2238                  * system.
2239                  */
2240                 for (i = last_i; i < len; i++) {
2241                         if (call->class->system == map[i]->system) {
2242                                 /* Save the first system if need be */
2243                                 if (first) {
2244                                         last_i = i;
2245                                         first = false;
2246                                 }
2247                                 update_event_printk(call, map[i]);
2248                         }
2249                 }
2250         }
2251         up_write(&trace_event_sem);
2252 }
2253
2254 static struct trace_event_file *
2255 trace_create_new_event(struct trace_event_call *call,
2256                        struct trace_array *tr)
2257 {
2258         struct trace_event_file *file;
2259
2260         file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2261         if (!file)
2262                 return NULL;
2263
2264         file->event_call = call;
2265         file->tr = tr;
2266         atomic_set(&file->sm_ref, 0);
2267         atomic_set(&file->tm_ref, 0);
2268         INIT_LIST_HEAD(&file->triggers);
2269         list_add(&file->list, &tr->events);
2270
2271         return file;
2272 }
2273
2274 /* Add an event to a trace directory */
2275 static int
2276 __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2277 {
2278         struct trace_event_file *file;
2279
2280         file = trace_create_new_event(call, tr);
2281         if (!file)
2282                 return -ENOMEM;
2283
2284         return event_create_dir(tr->event_dir, file);
2285 }
2286
2287 /*
2288  * Just create a decriptor for early init. A descriptor is required
2289  * for enabling events at boot. We want to enable events before
2290  * the filesystem is initialized.
2291  */
2292 static __init int
2293 __trace_early_add_new_event(struct trace_event_call *call,
2294                             struct trace_array *tr)
2295 {
2296         struct trace_event_file *file;
2297
2298         file = trace_create_new_event(call, tr);
2299         if (!file)
2300                 return -ENOMEM;
2301
2302         return 0;
2303 }
2304
2305 struct ftrace_module_file_ops;
2306 static void __add_event_to_tracers(struct trace_event_call *call);
2307
2308 int trace_add_event_call_nolock(struct trace_event_call *call)
2309 {
2310         int ret;
2311         lockdep_assert_held(&event_mutex);
2312
2313         mutex_lock(&trace_types_lock);
2314
2315         ret = __register_event(call, NULL);
2316         if (ret >= 0)
2317                 __add_event_to_tracers(call);
2318
2319         mutex_unlock(&trace_types_lock);
2320         return ret;
2321 }
2322
2323 /* Add an additional event_call dynamically */
2324 int trace_add_event_call(struct trace_event_call *call)
2325 {
2326         int ret;
2327
2328         mutex_lock(&event_mutex);
2329         ret = trace_add_event_call_nolock(call);
2330         mutex_unlock(&event_mutex);
2331         return ret;
2332 }
2333
2334 /*
2335  * Must be called under locking of trace_types_lock, event_mutex and
2336  * trace_event_sem.
2337  */
2338 static void __trace_remove_event_call(struct trace_event_call *call)
2339 {
2340         event_remove(call);
2341         trace_destroy_fields(call);
2342         free_event_filter(call->filter);
2343         call->filter = NULL;
2344 }
2345
2346 static int probe_remove_event_call(struct trace_event_call *call)
2347 {
2348         struct trace_array *tr;
2349         struct trace_event_file *file;
2350
2351 #ifdef CONFIG_PERF_EVENTS
2352         if (call->perf_refcount)
2353                 return -EBUSY;
2354 #endif
2355         do_for_each_event_file(tr, file) {
2356                 if (file->event_call != call)
2357                         continue;
2358                 /*
2359                  * We can't rely on ftrace_event_enable_disable(enable => 0)
2360                  * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
2361                  * TRACE_REG_UNREGISTER.
2362                  */
2363                 if (file->flags & EVENT_FILE_FL_ENABLED)
2364                         return -EBUSY;
2365                 /*
2366                  * The do_for_each_event_file_safe() is
2367                  * a double loop. After finding the call for this
2368                  * trace_array, we use break to jump to the next
2369                  * trace_array.
2370                  */
2371                 break;
2372         } while_for_each_event_file();
2373
2374         __trace_remove_event_call(call);
2375
2376         return 0;
2377 }
2378
2379 /* no event_mutex version */
2380 int trace_remove_event_call_nolock(struct trace_event_call *call)
2381 {
2382         int ret;
2383
2384         lockdep_assert_held(&event_mutex);
2385
2386         mutex_lock(&trace_types_lock);
2387         down_write(&trace_event_sem);
2388         ret = probe_remove_event_call(call);
2389         up_write(&trace_event_sem);
2390         mutex_unlock(&trace_types_lock);
2391
2392         return ret;
2393 }
2394
2395 /* Remove an event_call */
2396 int trace_remove_event_call(struct trace_event_call *call)
2397 {
2398         int ret;
2399
2400         mutex_lock(&event_mutex);
2401         ret = trace_remove_event_call_nolock(call);
2402         mutex_unlock(&event_mutex);
2403
2404         return ret;
2405 }
2406
2407 #define for_each_event(event, start, end)                       \
2408         for (event = start;                                     \
2409              (unsigned long)event < (unsigned long)end;         \
2410              event++)
2411
2412 #ifdef CONFIG_MODULES
2413
2414 static void trace_module_add_events(struct module *mod)
2415 {
2416         struct trace_event_call **call, **start, **end;
2417
2418         if (!mod->num_trace_events)
2419                 return;
2420
2421         /* Don't add infrastructure for mods without tracepoints */
2422         if (trace_module_has_bad_taint(mod)) {
2423                 pr_err("%s: module has bad taint, not creating trace events\n",
2424                        mod->name);
2425                 return;
2426         }
2427
2428         start = mod->trace_events;
2429         end = mod->trace_events + mod->num_trace_events;
2430
2431         for_each_event(call, start, end) {
2432                 __register_event(*call, mod);
2433                 __add_event_to_tracers(*call);
2434         }
2435 }
2436
2437 static void trace_module_remove_events(struct module *mod)
2438 {
2439         struct trace_event_call *call, *p;
2440
2441         down_write(&trace_event_sem);
2442         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2443                 if (call->mod == mod)
2444                         __trace_remove_event_call(call);
2445         }
2446         up_write(&trace_event_sem);
2447
2448         /*
2449          * It is safest to reset the ring buffer if the module being unloaded
2450          * registered any events that were used. The only worry is if
2451          * a new module gets loaded, and takes on the same id as the events
2452          * of this module. When printing out the buffer, traced events left
2453          * over from this module may be passed to the new module events and
2454          * unexpected results may occur.
2455          */
2456         tracing_reset_all_online_cpus();
2457 }
2458
2459 static int trace_module_notify(struct notifier_block *self,
2460                                unsigned long val, void *data)
2461 {
2462         struct module *mod = data;
2463
2464         mutex_lock(&event_mutex);
2465         mutex_lock(&trace_types_lock);
2466         switch (val) {
2467         case MODULE_STATE_COMING:
2468                 trace_module_add_events(mod);
2469                 break;
2470         case MODULE_STATE_GOING:
2471                 trace_module_remove_events(mod);
2472                 break;
2473         }
2474         mutex_unlock(&trace_types_lock);
2475         mutex_unlock(&event_mutex);
2476
2477         return 0;
2478 }
2479
2480 static struct notifier_block trace_module_nb = {
2481         .notifier_call = trace_module_notify,
2482         .priority = 1, /* higher than trace.c module notify */
2483 };
2484 #endif /* CONFIG_MODULES */
2485
2486 /* Create a new event directory structure for a trace directory. */
2487 static void
2488 __trace_add_event_dirs(struct trace_array *tr)
2489 {
2490         struct trace_event_call *call;
2491         int ret;
2492
2493         list_for_each_entry(call, &ftrace_events, list) {
2494                 ret = __trace_add_new_event(call, tr);
2495                 if (ret < 0)
2496                         pr_warn("Could not create directory for event %s\n",
2497                                 trace_event_name(call));
2498         }
2499 }
2500
2501 /* Returns any file that matches the system and event */
2502 struct trace_event_file *
2503 __find_event_file(struct trace_array *tr, const char *system, const char *event)
2504 {
2505         struct trace_event_file *file;
2506         struct trace_event_call *call;
2507         const char *name;
2508
2509         list_for_each_entry(file, &tr->events, list) {
2510
2511                 call = file->event_call;
2512                 name = trace_event_name(call);
2513
2514                 if (!name || !call->class)
2515                         continue;
2516
2517                 if (strcmp(event, name) == 0 &&
2518                     strcmp(system, call->class->system) == 0)
2519                         return file;
2520         }
2521         return NULL;
2522 }
2523
2524 /* Returns valid trace event files that match system and event */
2525 struct trace_event_file *
2526 find_event_file(struct trace_array *tr, const char *system, const char *event)
2527 {
2528         struct trace_event_file *file;
2529
2530         file = __find_event_file(tr, system, event);
2531         if (!file || !file->event_call->class->reg ||
2532             file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
2533                 return NULL;
2534
2535         return file;
2536 }
2537
2538 #ifdef CONFIG_DYNAMIC_FTRACE
2539
2540 /* Avoid typos */
2541 #define ENABLE_EVENT_STR        "enable_event"
2542 #define DISABLE_EVENT_STR       "disable_event"
2543
2544 struct event_probe_data {
2545         struct trace_event_file *file;
2546         unsigned long                   count;
2547         int                             ref;
2548         bool                            enable;
2549 };
2550
2551 static void update_event_probe(struct event_probe_data *data)
2552 {
2553         if (data->enable)
2554                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2555         else
2556                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2557 }
2558
2559 static void
2560 event_enable_probe(unsigned long ip, unsigned long parent_ip,
2561                    struct trace_array *tr, struct ftrace_probe_ops *ops,
2562                    void *data)
2563 {
2564         struct ftrace_func_mapper *mapper = data;
2565         struct event_probe_data *edata;
2566         void **pdata;
2567
2568         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2569         if (!pdata || !*pdata)
2570                 return;
2571
2572         edata = *pdata;
2573         update_event_probe(edata);
2574 }
2575
2576 static void
2577 event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
2578                          struct trace_array *tr, struct ftrace_probe_ops *ops,
2579                          void *data)
2580 {
2581         struct ftrace_func_mapper *mapper = data;
2582         struct event_probe_data *edata;
2583         void **pdata;
2584
2585         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2586         if (!pdata || !*pdata)
2587                 return;
2588
2589         edata = *pdata;
2590
2591         if (!edata->count)
2592                 return;
2593
2594         /* Skip if the event is in a state we want to switch to */
2595         if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
2596                 return;
2597
2598         if (edata->count != -1)
2599                 (edata->count)--;
2600
2601         update_event_probe(edata);
2602 }
2603
2604 static int
2605 event_enable_print(struct seq_file *m, unsigned long ip,
2606                    struct ftrace_probe_ops *ops, void *data)
2607 {
2608         struct ftrace_func_mapper *mapper = data;
2609         struct event_probe_data *edata;
2610         void **pdata;
2611
2612         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2613
2614         if (WARN_ON_ONCE(!pdata || !*pdata))
2615                 return 0;
2616
2617         edata = *pdata;
2618
2619         seq_printf(m, "%ps:", (void *)ip);
2620
2621         seq_printf(m, "%s:%s:%s",
2622                    edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
2623                    edata->file->event_call->class->system,
2624                    trace_event_name(edata->file->event_call));
2625
2626         if (edata->count == -1)
2627                 seq_puts(m, ":unlimited\n");
2628         else
2629                 seq_printf(m, ":count=%ld\n", edata->count);
2630
2631         return 0;
2632 }
2633
2634 static int
2635 event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
2636                   unsigned long ip, void *init_data, void **data)
2637 {
2638         struct ftrace_func_mapper *mapper = *data;
2639         struct event_probe_data *edata = init_data;
2640         int ret;
2641
2642         if (!mapper) {
2643                 mapper = allocate_ftrace_func_mapper();
2644                 if (!mapper)
2645                         return -ENODEV;
2646                 *data = mapper;
2647         }
2648
2649         ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
2650         if (ret < 0)
2651                 return ret;
2652
2653         edata->ref++;
2654
2655         return 0;
2656 }
2657
2658 static int free_probe_data(void *data)
2659 {
2660         struct event_probe_data *edata = data;
2661
2662         edata->ref--;
2663         if (!edata->ref) {
2664                 /* Remove the SOFT_MODE flag */
2665                 __ftrace_event_enable_disable(edata->file, 0, 1);
2666                 module_put(edata->file->event_call->mod);
2667                 kfree(edata);
2668         }
2669         return 0;
2670 }
2671
2672 static void
2673 event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
2674                   unsigned long ip, void *data)
2675 {
2676         struct ftrace_func_mapper *mapper = data;
2677         struct event_probe_data *edata;
2678
2679         if (!ip) {
2680                 if (!mapper)
2681                         return;
2682                 free_ftrace_func_mapper(mapper, free_probe_data);
2683                 return;
2684         }
2685
2686         edata = ftrace_func_mapper_remove_ip(mapper, ip);
2687
2688         if (WARN_ON_ONCE(!edata))
2689                 return;
2690
2691         if (WARN_ON_ONCE(edata->ref <= 0))
2692                 return;
2693
2694         free_probe_data(edata);
2695 }
2696
2697 static struct ftrace_probe_ops event_enable_probe_ops = {
2698         .func                   = event_enable_probe,
2699         .print                  = event_enable_print,
2700         .init                   = event_enable_init,
2701         .free                   = event_enable_free,
2702 };
2703
2704 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2705         .func                   = event_enable_count_probe,
2706         .print                  = event_enable_print,
2707         .init                   = event_enable_init,
2708         .free                   = event_enable_free,
2709 };
2710
2711 static struct ftrace_probe_ops event_disable_probe_ops = {
2712         .func                   = event_enable_probe,
2713         .print                  = event_enable_print,
2714         .init                   = event_enable_init,
2715         .free                   = event_enable_free,
2716 };
2717
2718 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2719         .func                   = event_enable_count_probe,
2720         .print                  = event_enable_print,
2721         .init                   = event_enable_init,
2722         .free                   = event_enable_free,
2723 };
2724
2725 static int
2726 event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
2727                   char *glob, char *cmd, char *param, int enabled)
2728 {
2729         struct trace_event_file *file;
2730         struct ftrace_probe_ops *ops;
2731         struct event_probe_data *data;
2732         const char *system;
2733         const char *event;
2734         char *number;
2735         bool enable;
2736         int ret;
2737
2738         if (!tr)
2739                 return -ENODEV;
2740
2741         /* hash funcs only work with set_ftrace_filter */
2742         if (!enabled || !param)
2743                 return -EINVAL;
2744
2745         system = strsep(&param, ":");
2746         if (!param)
2747                 return -EINVAL;
2748
2749         event = strsep(&param, ":");
2750
2751         mutex_lock(&event_mutex);
2752
2753         ret = -EINVAL;
2754         file = find_event_file(tr, system, event);
2755         if (!file)
2756                 goto out;
2757
2758         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2759
2760         if (enable)
2761                 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2762         else
2763                 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2764
2765         if (glob[0] == '!') {
2766                 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
2767                 goto out;
2768         }
2769
2770         ret = -ENOMEM;
2771
2772         data = kzalloc(sizeof(*data), GFP_KERNEL);
2773         if (!data)
2774                 goto out;
2775
2776         data->enable = enable;
2777         data->count = -1;
2778         data->file = file;
2779
2780         if (!param)
2781                 goto out_reg;
2782
2783         number = strsep(&param, ":");
2784
2785         ret = -EINVAL;
2786         if (!strlen(number))
2787                 goto out_free;
2788
2789         /*
2790          * We use the callback data field (which is a pointer)
2791          * as our counter.
2792          */
2793         ret = kstrtoul(number, 0, &data->count);
2794         if (ret)
2795                 goto out_free;
2796
2797  out_reg:
2798         /* Don't let event modules unload while probe registered */
2799         ret = try_module_get(file->event_call->mod);
2800         if (!ret) {
2801                 ret = -EBUSY;
2802                 goto out_free;
2803         }
2804
2805         ret = __ftrace_event_enable_disable(file, 1, 1);
2806         if (ret < 0)
2807                 goto out_put;
2808
2809         ret = register_ftrace_function_probe(glob, tr, ops, data);
2810         /*
2811          * The above returns on success the # of functions enabled,
2812          * but if it didn't find any functions it returns zero.
2813          * Consider no functions a failure too.
2814          */
2815         if (!ret) {
2816                 ret = -ENOENT;
2817                 goto out_disable;
2818         } else if (ret < 0)
2819                 goto out_disable;
2820         /* Just return zero, not the number of enabled functions */
2821         ret = 0;
2822  out:
2823         mutex_unlock(&event_mutex);
2824         return ret;
2825
2826  out_disable:
2827         __ftrace_event_enable_disable(file, 0, 1);
2828  out_put:
2829         module_put(file->event_call->mod);
2830  out_free:
2831         kfree(data);
2832         goto out;
2833 }
2834
2835 static struct ftrace_func_command event_enable_cmd = {
2836         .name                   = ENABLE_EVENT_STR,
2837         .func                   = event_enable_func,
2838 };
2839
2840 static struct ftrace_func_command event_disable_cmd = {
2841         .name                   = DISABLE_EVENT_STR,
2842         .func                   = event_enable_func,
2843 };
2844
2845 static __init int register_event_cmds(void)
2846 {
2847         int ret;
2848
2849         ret = register_ftrace_command(&event_enable_cmd);
2850         if (WARN_ON(ret < 0))
2851                 return ret;
2852         ret = register_ftrace_command(&event_disable_cmd);
2853         if (WARN_ON(ret < 0))
2854                 unregister_ftrace_command(&event_enable_cmd);
2855         return ret;
2856 }
2857 #else
2858 static inline int register_event_cmds(void) { return 0; }
2859 #endif /* CONFIG_DYNAMIC_FTRACE */
2860
2861 /*
2862  * The top level array has already had its trace_event_file
2863  * descriptors created in order to allow for early events to
2864  * be recorded. This function is called after the tracefs has been
2865  * initialized, and we now have to create the files associated
2866  * to the events.
2867  */
2868 static __init void
2869 __trace_early_add_event_dirs(struct trace_array *tr)
2870 {
2871         struct trace_event_file *file;
2872         int ret;
2873
2874
2875         list_for_each_entry(file, &tr->events, list) {
2876                 ret = event_create_dir(tr->event_dir, file);
2877                 if (ret < 0)
2878                         pr_warn("Could not create directory for event %s\n",
2879                                 trace_event_name(file->event_call));
2880         }
2881 }
2882
2883 /*
2884  * For early boot up, the top trace array requires to have
2885  * a list of events that can be enabled. This must be done before
2886  * the filesystem is set up in order to allow events to be traced
2887  * early.
2888  */
2889 static __init void
2890 __trace_early_add_events(struct trace_array *tr)
2891 {
2892         struct trace_event_call *call;
2893         int ret;
2894
2895         list_for_each_entry(call, &ftrace_events, list) {
2896                 /* Early boot up should not have any modules loaded */
2897                 if (WARN_ON_ONCE(call->mod))
2898                         continue;
2899
2900                 ret = __trace_early_add_new_event(call, tr);
2901                 if (ret < 0)
2902                         pr_warn("Could not create early event %s\n",
2903                                 trace_event_name(call));
2904         }
2905 }
2906
2907 /* Remove the event directory structure for a trace directory. */
2908 static void
2909 __trace_remove_event_dirs(struct trace_array *tr)
2910 {
2911         struct trace_event_file *file, *next;
2912
2913         list_for_each_entry_safe(file, next, &tr->events, list)
2914                 remove_event_file_dir(file);
2915 }
2916
2917 static void __add_event_to_tracers(struct trace_event_call *call)
2918 {
2919         struct trace_array *tr;
2920
2921         list_for_each_entry(tr, &ftrace_trace_arrays, list)
2922                 __trace_add_new_event(call, tr);
2923 }
2924
2925 extern struct trace_event_call *__start_ftrace_events[];
2926 extern struct trace_event_call *__stop_ftrace_events[];
2927
2928 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2929
2930 static __init int setup_trace_event(char *str)
2931 {
2932         strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2933         ring_buffer_expanded = true;
2934         tracing_selftest_disabled = true;
2935
2936         return 1;
2937 }
2938 __setup("trace_event=", setup_trace_event);
2939
2940 /* Expects to have event_mutex held when called */
2941 static int
2942 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2943 {
2944         struct dentry *d_events;
2945         struct dentry *entry;
2946
2947         entry = tracefs_create_file("set_event", 0644, parent,
2948                                     tr, &ftrace_set_event_fops);
2949         if (!entry) {
2950                 pr_warn("Could not create tracefs 'set_event' entry\n");
2951                 return -ENOMEM;
2952         }
2953
2954         d_events = tracefs_create_dir("events", parent);
2955         if (!d_events) {
2956                 pr_warn("Could not create tracefs 'events' directory\n");
2957                 return -ENOMEM;
2958         }
2959
2960         entry = trace_create_file("enable", 0644, d_events,
2961                                   tr, &ftrace_tr_enable_fops);
2962         if (!entry) {
2963                 pr_warn("Could not create tracefs 'enable' entry\n");
2964                 return -ENOMEM;
2965         }
2966
2967         /* There are not as crucial, just warn if they are not created */
2968
2969         entry = tracefs_create_file("set_event_pid", 0644, parent,
2970                                     tr, &ftrace_set_event_pid_fops);
2971         if (!entry)
2972                 pr_warn("Could not create tracefs 'set_event_pid' entry\n");
2973
2974         /* ring buffer internal formats */
2975         entry = trace_create_file("header_page", 0444, d_events,
2976                                   ring_buffer_print_page_header,
2977                                   &ftrace_show_header_fops);
2978         if (!entry)
2979                 pr_warn("Could not create tracefs 'header_page' entry\n");
2980
2981         entry = trace_create_file("header_event", 0444, d_events,
2982                                   ring_buffer_print_entry_header,
2983                                   &ftrace_show_header_fops);
2984         if (!entry)
2985                 pr_warn("Could not create tracefs 'header_event' entry\n");
2986
2987         tr->event_dir = d_events;
2988
2989         return 0;
2990 }
2991
2992 /**
2993  * event_trace_add_tracer - add a instance of a trace_array to events
2994  * @parent: The parent dentry to place the files/directories for events in
2995  * @tr: The trace array associated with these events
2996  *
2997  * When a new instance is created, it needs to set up its events
2998  * directory, as well as other files associated with events. It also
2999  * creates the event hierachry in the @parent/events directory.
3000  *
3001  * Returns 0 on success.
3002  *
3003  * Must be called with event_mutex held.
3004  */
3005 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
3006 {
3007         int ret;
3008
3009         lockdep_assert_held(&event_mutex);
3010
3011         ret = create_event_toplevel_files(parent, tr);
3012         if (ret)
3013                 goto out;
3014
3015         down_write(&trace_event_sem);
3016         __trace_add_event_dirs(tr);
3017         up_write(&trace_event_sem);
3018
3019  out:
3020         return ret;
3021 }
3022
3023 /*
3024  * The top trace array already had its file descriptors created.
3025  * Now the files themselves need to be created.
3026  */
3027 static __init int
3028 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
3029 {
3030         int ret;
3031
3032         mutex_lock(&event_mutex);
3033
3034         ret = create_event_toplevel_files(parent, tr);
3035         if (ret)
3036                 goto out_unlock;
3037
3038         down_write(&trace_event_sem);
3039         __trace_early_add_event_dirs(tr);
3040         up_write(&trace_event_sem);
3041
3042  out_unlock:
3043         mutex_unlock(&event_mutex);
3044
3045         return ret;
3046 }
3047
3048 /* Must be called with event_mutex held */
3049 int event_trace_del_tracer(struct trace_array *tr)
3050 {
3051         lockdep_assert_held(&event_mutex);
3052
3053         /* Disable any event triggers and associated soft-disabled events */
3054         clear_event_triggers(tr);
3055
3056         /* Clear the pid list */
3057         __ftrace_clear_event_pids(tr);
3058
3059         /* Disable any running events */
3060         __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3061
3062         /* Make sure no more events are being executed */
3063         tracepoint_synchronize_unregister();
3064
3065         down_write(&trace_event_sem);
3066         __trace_remove_event_dirs(tr);
3067         tracefs_remove_recursive(tr->event_dir);
3068         up_write(&trace_event_sem);
3069
3070         tr->event_dir = NULL;
3071
3072         return 0;
3073 }
3074
3075 static __init int event_trace_memsetup(void)
3076 {
3077         field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3078         file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3079         return 0;
3080 }
3081
3082 static __init void
3083 early_enable_events(struct trace_array *tr, bool disable_first)
3084 {
3085         char *buf = bootup_event_buf;
3086         char *token;
3087         int ret;
3088
3089         while (true) {
3090                 token = strsep(&buf, ",");
3091
3092                 if (!token)
3093                         break;
3094
3095                 if (*token) {
3096                         /* Restarting syscalls requires that we stop them first */
3097                         if (disable_first)
3098                                 ftrace_set_clr_event(tr, token, 0);
3099
3100                         ret = ftrace_set_clr_event(tr, token, 1);
3101                         if (ret)
3102                                 pr_warn("Failed to enable trace event: %s\n", token);
3103                 }
3104
3105                 /* Put back the comma to allow this to be called again */
3106                 if (buf)
3107                         *(buf - 1) = ',';
3108         }
3109 }
3110
3111 static __init int event_trace_enable(void)
3112 {
3113         struct trace_array *tr = top_trace_array();
3114         struct trace_event_call **iter, *call;
3115         int ret;
3116
3117         if (!tr)
3118                 return -ENODEV;
3119
3120         for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3121
3122                 call = *iter;
3123                 ret = event_init(call);
3124                 if (!ret)
3125                         list_add(&call->list, &ftrace_events);
3126         }
3127
3128         /*
3129          * We need the top trace array to have a working set of trace
3130          * points at early init, before the debug files and directories
3131          * are created. Create the file entries now, and attach them
3132          * to the actual file dentries later.
3133          */
3134         __trace_early_add_events(tr);
3135
3136         early_enable_events(tr, false);
3137
3138         trace_printk_start_comm();
3139
3140         register_event_cmds();
3141
3142         register_trigger_cmds();
3143
3144         return 0;
3145 }
3146
3147 /*
3148  * event_trace_enable() is called from trace_event_init() first to
3149  * initialize events and perhaps start any events that are on the
3150  * command line. Unfortunately, there are some events that will not
3151  * start this early, like the system call tracepoints that need
3152  * to set the TIF_SYSCALL_TRACEPOINT flag of pid 1. But event_trace_enable()
3153  * is called before pid 1 starts, and this flag is never set, making
3154  * the syscall tracepoint never get reached, but the event is enabled
3155  * regardless (and not doing anything).
3156  */
3157 static __init int event_trace_enable_again(void)
3158 {
3159         struct trace_array *tr;
3160
3161         tr = top_trace_array();
3162         if (!tr)
3163                 return -ENODEV;
3164
3165         early_enable_events(tr, true);
3166
3167         return 0;
3168 }
3169
3170 early_initcall(event_trace_enable_again);
3171
3172 __init int event_trace_init(void)
3173 {
3174         struct trace_array *tr;
3175         struct dentry *d_tracer;
3176         struct dentry *entry;
3177         int ret;
3178
3179         tr = top_trace_array();
3180         if (!tr)
3181                 return -ENODEV;
3182
3183         d_tracer = tracing_init_dentry();
3184         if (IS_ERR(d_tracer))
3185                 return 0;
3186
3187         entry = tracefs_create_file("available_events", 0444, d_tracer,
3188                                     tr, &ftrace_avail_fops);
3189         if (!entry)
3190                 pr_warn("Could not create tracefs 'available_events' entry\n");
3191
3192         if (trace_define_generic_fields())
3193                 pr_warn("tracing: Failed to allocated generic fields");
3194
3195         if (trace_define_common_fields())
3196                 pr_warn("tracing: Failed to allocate common fields");
3197
3198         ret = early_event_add_tracer(d_tracer, tr);
3199         if (ret)
3200                 return ret;
3201
3202 #ifdef CONFIG_MODULES
3203         ret = register_module_notifier(&trace_module_nb);
3204         if (ret)
3205                 pr_warn("Failed to register trace events module notifier\n");
3206 #endif
3207         return 0;
3208 }
3209
3210 void __init trace_event_init(void)
3211 {
3212         event_trace_memsetup();
3213         init_ftrace_syscalls();
3214         event_trace_enable();
3215 }
3216
3217 #ifdef CONFIG_FTRACE_STARTUP_TEST
3218
3219 static DEFINE_SPINLOCK(test_spinlock);
3220 static DEFINE_SPINLOCK(test_spinlock_irq);
3221 static DEFINE_MUTEX(test_mutex);
3222
3223 static __init void test_work(struct work_struct *dummy)
3224 {
3225         spin_lock(&test_spinlock);
3226         spin_lock_irq(&test_spinlock_irq);
3227         udelay(1);
3228         spin_unlock_irq(&test_spinlock_irq);
3229         spin_unlock(&test_spinlock);
3230
3231         mutex_lock(&test_mutex);
3232         msleep(1);
3233         mutex_unlock(&test_mutex);
3234 }
3235
3236 static __init int event_test_thread(void *unused)
3237 {
3238         void *test_malloc;
3239
3240         test_malloc = kmalloc(1234, GFP_KERNEL);
3241         if (!test_malloc)
3242                 pr_info("failed to kmalloc\n");
3243
3244         schedule_on_each_cpu(test_work);
3245
3246         kfree(test_malloc);
3247
3248         set_current_state(TASK_INTERRUPTIBLE);
3249         while (!kthread_should_stop()) {
3250                 schedule();
3251                 set_current_state(TASK_INTERRUPTIBLE);
3252         }
3253         __set_current_state(TASK_RUNNING);
3254
3255         return 0;
3256 }
3257
3258 /*
3259  * Do various things that may trigger events.
3260  */
3261 static __init void event_test_stuff(void)
3262 {
3263         struct task_struct *test_thread;
3264
3265         test_thread = kthread_run(event_test_thread, NULL, "test-events");
3266         msleep(1);
3267         kthread_stop(test_thread);
3268 }
3269
3270 /*
3271  * For every trace event defined, we will test each trace point separately,
3272  * and then by groups, and finally all trace points.
3273  */
3274 static __init void event_trace_self_tests(void)
3275 {
3276         struct trace_subsystem_dir *dir;
3277         struct trace_event_file *file;
3278         struct trace_event_call *call;
3279         struct event_subsystem *system;
3280         struct trace_array *tr;
3281         int ret;
3282
3283         tr = top_trace_array();
3284         if (!tr)
3285                 return;
3286
3287         pr_info("Running tests on trace events:\n");
3288
3289         list_for_each_entry(file, &tr->events, list) {
3290
3291                 call = file->event_call;
3292
3293                 /* Only test those that have a probe */
3294                 if (!call->class || !call->class->probe)
3295                         continue;
3296
3297 /*
3298  * Testing syscall events here is pretty useless, but
3299  * we still do it if configured. But this is time consuming.
3300  * What we really need is a user thread to perform the
3301  * syscalls as we test.
3302  */
3303 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
3304                 if (call->class->system &&
3305                     strcmp(call->class->system, "syscalls") == 0)
3306                         continue;
3307 #endif
3308
3309                 pr_info("Testing event %s: ", trace_event_name(call));
3310
3311                 /*
3312                  * If an event is already enabled, someone is using
3313                  * it and the self test should not be on.
3314                  */
3315                 if (file->flags & EVENT_FILE_FL_ENABLED) {
3316                         pr_warn("Enabled event during self test!\n");
3317                         WARN_ON_ONCE(1);
3318                         continue;
3319                 }
3320
3321                 ftrace_event_enable_disable(file, 1);
3322                 event_test_stuff();
3323                 ftrace_event_enable_disable(file, 0);
3324
3325                 pr_cont("OK\n");
3326         }
3327
3328         /* Now test at the sub system level */
3329
3330         pr_info("Running tests on trace event systems:\n");
3331
3332         list_for_each_entry(dir, &tr->systems, list) {
3333
3334                 system = dir->subsystem;
3335
3336                 /* the ftrace system is special, skip it */
3337                 if (strcmp(system->name, "ftrace") == 0)
3338                         continue;
3339
3340                 pr_info("Testing event system %s: ", system->name);
3341
3342                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
3343                 if (WARN_ON_ONCE(ret)) {
3344                         pr_warn("error enabling system %s\n",
3345                                 system->name);
3346                         continue;
3347                 }
3348
3349                 event_test_stuff();
3350
3351                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
3352                 if (WARN_ON_ONCE(ret)) {
3353                         pr_warn("error disabling system %s\n",
3354                                 system->name);
3355                         continue;
3356                 }
3357
3358                 pr_cont("OK\n");
3359         }
3360
3361         /* Test with all events enabled */
3362
3363         pr_info("Running tests on all trace events:\n");
3364         pr_info("Testing all events: ");
3365
3366         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
3367         if (WARN_ON_ONCE(ret)) {
3368                 pr_warn("error enabling all events\n");
3369                 return;
3370         }
3371
3372         event_test_stuff();
3373
3374         /* reset sysname */
3375         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
3376         if (WARN_ON_ONCE(ret)) {
3377                 pr_warn("error disabling all events\n");
3378                 return;
3379         }
3380
3381         pr_cont("OK\n");
3382 }
3383
3384 #ifdef CONFIG_FUNCTION_TRACER
3385
3386 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
3387
3388 static struct trace_event_file event_trace_file __initdata;
3389
3390 static void __init
3391 function_test_events_call(unsigned long ip, unsigned long parent_ip,
3392                           struct ftrace_ops *op, struct pt_regs *pt_regs)
3393 {
3394         struct ring_buffer_event *event;
3395         struct ring_buffer *buffer;
3396         struct ftrace_entry *entry;
3397         unsigned long flags;
3398         long disabled;
3399         int cpu;
3400         int pc;
3401
3402         pc = preempt_count();
3403         preempt_disable_notrace();
3404         cpu = raw_smp_processor_id();
3405         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
3406
3407         if (disabled != 1)
3408                 goto out;
3409
3410         local_save_flags(flags);
3411
3412         event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
3413                                                 TRACE_FN, sizeof(*entry),
3414                                                 flags, pc);
3415         if (!event)
3416                 goto out;
3417         entry   = ring_buffer_event_data(event);
3418         entry->ip                       = ip;
3419         entry->parent_ip                = parent_ip;
3420
3421         event_trigger_unlock_commit(&event_trace_file, buffer, event,
3422                                     entry, flags, pc);
3423  out:
3424         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
3425         preempt_enable_notrace();
3426 }
3427
3428 static struct ftrace_ops trace_ops __initdata  =
3429 {
3430         .func = function_test_events_call,
3431         .flags = FTRACE_OPS_FL_RECURSION_SAFE,
3432 };
3433
3434 static __init void event_trace_self_test_with_function(void)
3435 {
3436         int ret;
3437
3438         event_trace_file.tr = top_trace_array();
3439         if (WARN_ON(!event_trace_file.tr))
3440                 return;
3441
3442         ret = register_ftrace_function(&trace_ops);
3443         if (WARN_ON(ret < 0)) {
3444                 pr_info("Failed to enable function tracer for event tests\n");
3445                 return;
3446         }
3447         pr_info("Running tests again, along with the function tracer\n");
3448         event_trace_self_tests();
3449         unregister_ftrace_function(&trace_ops);
3450 }
3451 #else
3452 static __init void event_trace_self_test_with_function(void)
3453 {
3454 }
3455 #endif
3456
3457 static __init int event_trace_self_tests_init(void)
3458 {
3459         if (!tracing_selftest_disabled) {
3460                 event_trace_self_tests();
3461                 event_trace_self_test_with_function();
3462         }
3463
3464         return 0;
3465 }
3466
3467 late_initcall(event_trace_self_tests_init);
3468
3469 #endif