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/security.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/kthread.h>
  18 #include <linux/tracefs.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/module.h>
  21 #include <linux/ctype.h>
  22 #include <linux/sort.h>
  23 #include <linux/slab.h>
  24 #include <linux/delay.h>
  25
  26 #include <trace/events/sched.h>
  27 #include <trace/syscall.h>
  28
  29 #include <asm/setup.h>
  30
  31 #include "trace_output.h"
  32
  33 #undef TRACE_SYSTEM
  34 #define TRACE_SYSTEM "TRACE_SYSTEM"
  35
  36 DEFINE_MUTEX(event_mutex);
  37
  38 LIST_HEAD(ftrace_events);
  39 static LIST_HEAD(ftrace_generic_fields);
  40 static LIST_HEAD(ftrace_common_fields);
  41 static bool eventdir_initialized;
  42
  43 static LIST_HEAD(module_strings);
  44
  45 struct module_string {
  46         struct list_head        next;
  47         struct module           *module;
  48         char                    *str;
  49 };
  50
  51 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
  52
  53 static struct kmem_cache *field_cachep;
  54 static struct kmem_cache *file_cachep;
  55
  56 static inline int system_refcount(struct event_subsystem *system)
  57 {
  58         return system->ref_count;
  59 }
  60
  61 static int system_refcount_inc(struct event_subsystem *system)
  62 {
  63         return system->ref_count++;
  64 }
  65
  66 static int system_refcount_dec(struct event_subsystem *system)
  67 {
  68         return --system->ref_count;
  69 }
  70
  71 /* Double loops, do not use break, only goto's work */
  72 #define do_for_each_event_file(tr, file)                        \
  73         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
  74                 list_for_each_entry(file, &tr->events, list)
  75
  76 #define do_for_each_event_file_safe(tr, file)                   \
  77         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
  78                 struct trace_event_file *___n;                          \
  79                 list_for_each_entry_safe(file, ___n, &tr->events, list)
  80
  81 #define while_for_each_event_file()             \
  82         }
  83
  84 static struct ftrace_event_field *
  85 __find_event_field(struct list_head *head, char *name)
  86 {
  87         struct ftrace_event_field *field;
  88
  89         list_for_each_entry(field, head, link) {
  90                 if (!strcmp(field->name, name))
  91                         return field;
  92         }
  93
  94         return NULL;
  95 }
  96
  97 struct ftrace_event_field *
  98 trace_find_event_field(struct trace_event_call *call, char *name)
  99 {
 100         struct ftrace_event_field *field;
 101         struct list_head *head;
 102
 103         head = trace_get_fields(call);
 104         field = __find_event_field(head, name);
 105         if (field)
 106                 return field;
 107
 108         field = __find_event_field(&ftrace_generic_fields, name);
 109         if (field)
 110                 return field;
 111
 112         return __find_event_field(&ftrace_common_fields, name);
 113 }
 114
 115 static int __trace_define_field(struct list_head *head, const char *type,
 116                                 const char *name, int offset, int size,
 117                                 int is_signed, int filter_type)
 118 {
 119         struct ftrace_event_field *field;
 120
 121         field = kmem_cache_alloc(field_cachep, GFP_TRACE);
 122         if (!field)
 123                 return -ENOMEM;
 124
 125         field->name = name;
 126         field->type = type;
 127
 128         if (filter_type == FILTER_OTHER)
 129                 field->filter_type = filter_assign_type(type);
 130         else
 131                 field->filter_type = filter_type;
 132
 133         field->offset = offset;
 134         field->size = size;
 135         field->is_signed = is_signed;
 136
 137         list_add(&field->link, head);
 138
 139         return 0;
 140 }
 141
 142 int trace_define_field(struct trace_event_call *call, const char *type,
 143                        const char *name, int offset, int size, int is_signed,
 144                        int filter_type)
 145 {
 146         struct list_head *head;
 147
 148         if (WARN_ON(!call->class))
 149                 return 0;
 150
 151         head = trace_get_fields(call);
 152         return __trace_define_field(head, type, name, offset, size,
 153                                     is_signed, filter_type);
 154 }
 155 EXPORT_SYMBOL_GPL(trace_define_field);
 156
 157 #define __generic_field(type, item, filter_type)                        \
 158         ret = __trace_define_field(&ftrace_generic_fields, #type,       \
 159                                    #item, 0, 0, is_signed_type(type),   \
 160                                    filter_type);                        \
 161         if (ret)                                                        \
 162                 return ret;
 163
 164 #define __common_field(type, item)                                      \
 165         ret = __trace_define_field(&ftrace_common_fields, #type,        \
 166                                    "common_" #item,                     \
 167                                    offsetof(typeof(ent), item),         \
 168                                    sizeof(ent.item),                    \
 169                                    is_signed_type(type), FILTER_OTHER); \
 170         if (ret)                                                        \
 171                 return ret;
 172
 173 static int trace_define_generic_fields(void)
 174 {
 175         int ret;
 176
 177         __generic_field(int, CPU, FILTER_CPU);
 178         __generic_field(int, cpu, FILTER_CPU);
 179         __generic_field(int, common_cpu, FILTER_CPU);
 180         __generic_field(char *, COMM, FILTER_COMM);
 181         __generic_field(char *, comm, FILTER_COMM);
 182
 183         return ret;
 184 }
 185
 186 static int trace_define_common_fields(void)
 187 {
 188         int ret;
 189         struct trace_entry ent;
 190
 191         __common_field(unsigned short, type);
 192         __common_field(unsigned char, flags);
 193         /* Holds both preempt_count and migrate_disable */
 194         __common_field(unsigned char, preempt_count);
 195         __common_field(int, pid);
 196
 197         return ret;
 198 }
 199
 200 static void trace_destroy_fields(struct trace_event_call *call)
 201 {
 202         struct ftrace_event_field *field, *next;
 203         struct list_head *head;
 204
 205         head = trace_get_fields(call);
 206         list_for_each_entry_safe(field, next, head, link) {
 207                 list_del(&field->link);
 208                 kmem_cache_free(field_cachep, field);
 209         }
 210 }
 211
 212 /*
 213  * run-time version of trace_event_get_offsets_<call>() that returns the last
 214  * accessible offset of trace fields excluding __dynamic_array bytes
 215  */
 216 int trace_event_get_offsets(struct trace_event_call *call)
 217 {
 218         struct ftrace_event_field *tail;
 219         struct list_head *head;
 220
 221         head = trace_get_fields(call);
 222         /*
 223          * head->next points to the last field with the largest offset,
 224          * since it was added last by trace_define_field()
 225          */
 226         tail = list_first_entry(head, struct ftrace_event_field, link);
 227         return tail->offset + tail->size;
 228 }
 229
 230 /*
 231  * Check if the referenced field is an array and return true,
 232  * as arrays are OK to dereference.
 233  */
 234 static bool test_field(const char *fmt, struct trace_event_call *call)
 235 {
 236         struct trace_event_fields *field = call->class->fields_array;
 237         const char *array_descriptor;
 238         const char *p = fmt;
 239         int len;
 240
 241         if (!(len = str_has_prefix(fmt, "REC->")))
 242                 return false;
 243         fmt += len;
 244         for (p = fmt; *p; p++) {
 245                 if (!isalnum(*p) && *p != '_')
 246                         break;
 247         }
 248         len = p - fmt;
 249
 250         for (; field->type; field++) {
 251                 if (strncmp(field->name, fmt, len) ||
 252                     field->name[len])
 253                         continue;
 254                 array_descriptor = strchr(field->type, '[');
 255                 /* This is an array and is OK to dereference. */
 256                 return array_descriptor != NULL;
 257         }
 258         return false;
 259 }
 260
 261 /*
 262  * Examine the print fmt of the event looking for unsafe dereference
 263  * pointers using %p* that could be recorded in the trace event and
 264  * much later referenced after the pointer was freed. Dereferencing
 265  * pointers are OK, if it is dereferenced into the event itself.
 266  */
 267 static void test_event_printk(struct trace_event_call *call)
 268 {
 269         u64 dereference_flags = 0;
 270         bool first = true;
 271         const char *fmt, *c, *r, *a;
 272         int parens = 0;
 273         char in_quote = 0;
 274         int start_arg = 0;
 275         int arg = 0;
 276         int i;
 277
 278         fmt = call->print_fmt;
 279
 280         if (!fmt)
 281                 return;
 282
 283         for (i = 0; fmt[i]; i++) {
 284                 switch (fmt[i]) {
 285                 case '\\':
 286                         i++;
 287                         if (!fmt[i])
 288                                 return;
 289                         continue;
 290                 case '"':
 291                 case '\'':
 292                         /*
 293                          * The print fmt starts with a string that
 294                          * is processed first to find %p* usage,
 295                          * then after the first string, the print fmt
 296                          * contains arguments that are used to check
 297                          * if the dereferenced %p* usage is safe.
 298                          */
 299                         if (first) {
 300                                 if (fmt[i] == '\'')
 301                                         continue;
 302                                 if (in_quote) {
 303                                         arg = 0;
 304                                         first = false;
 305                                         /*
 306                                          * If there was no %p* uses
 307                                          * the fmt is OK.
 308                                          */
 309                                         if (!dereference_flags)
 310                                                 return;
 311                                 }
 312                         }
 313                         if (in_quote) {
 314                                 if (in_quote == fmt[i])
 315                                         in_quote = 0;
 316                         } else {
 317                                 in_quote = fmt[i];
 318                         }
 319                         continue;
 320                 case '%':
 321                         if (!first || !in_quote)
 322                                 continue;
 323                         i++;
 324                         if (!fmt[i])
 325                                 return;
 326                         switch (fmt[i]) {
 327                         case '%':
 328                                 continue;
 329                         case 'p':
 330                                 /* Find dereferencing fields */
 331                                 switch (fmt[i + 1]) {
 332                                 case 'B': case 'R': case 'r':
 333                                 case 'b': case 'M': case 'm':
 334                                 case 'I': case 'i': case 'E':
 335                                 case 'U': case 'V': case 'N':
 336                                 case 'a': case 'd': case 'D':
 337                                 case 'g': case 't': case 'C':
 338                                 case 'O': case 'f':
 339                                         if (WARN_ONCE(arg == 63,
 340                                                       "Too many args for event: %s",
 341                                                       trace_event_name(call)))
 342                                                 return;
 343                                         dereference_flags |= 1ULL << arg;
 344                                 }
 345                                 break;
 346                         default:
 347                         {
 348                                 bool star = false;
 349                                 int j;
 350
 351                                 /* Increment arg if %*s exists. */
 352                                 for (j = 0; fmt[i + j]; j++) {
 353                                         if (isdigit(fmt[i + j]) ||
 354                                             fmt[i + j] == '.')
 355                                                 continue;
 356                                         if (fmt[i + j] == '*') {
 357                                                 star = true;
 358                                                 continue;
 359                                         }
 360                                         if ((fmt[i + j] == 's') && star)
 361                                                 arg++;
 362                                         break;
 363                                 }
 364                                 break;
 365                         } /* default */
 366
 367                         } /* switch */
 368                         arg++;
 369                         continue;
 370                 case '(':
 371                         if (in_quote)
 372                                 continue;
 373                         parens++;
 374                         continue;
 375                 case ')':
 376                         if (in_quote)
 377                                 continue;
 378                         parens--;
 379                         if (WARN_ONCE(parens < 0,
 380                                       "Paren mismatch for event: %s\narg='%s'\n%*s",
 381                                       trace_event_name(call),
 382                                       fmt + start_arg,
 383                                       (i - start_arg) + 5, "^"))
 384                                 return;
 385                         continue;
 386                 case ',':
 387                         if (in_quote || parens)
 388                                 continue;
 389                         i++;
 390                         while (isspace(fmt[i]))
 391                                 i++;
 392                         start_arg = i;
 393                         if (!(dereference_flags & (1ULL << arg)))
 394                                 goto next_arg;
 395
 396                         /* Find the REC-> in the argument */
 397                         c = strchr(fmt + i, ',');
 398                         r = strstr(fmt + i, "REC->");
 399                         if (r && (!c || r < c)) {
 400                                 /*
 401                                  * Addresses of events on the buffer,
 402                                  * or an array on the buffer is
 403                                  * OK to dereference.
 404                                  * There's ways to fool this, but
 405                                  * this is to catch common mistakes,
 406                                  * not malicious code.
 407                                  */
 408                                 a = strchr(fmt + i, '&');
 409                                 if ((a && (a < r)) || test_field(r, call))
 410                                         dereference_flags &= ~(1ULL << arg);
 411                         } else if ((r = strstr(fmt + i, "__get_dynamic_array(")) &&
 412                                    (!c || r < c)) {
 413                                 dereference_flags &= ~(1ULL << arg);
 414                         } else if ((r = strstr(fmt + i, "__get_sockaddr(")) &&
 415                                    (!c || r < c)) {
 416                                 dereference_flags &= ~(1ULL << arg);
 417                         }
 418
 419                 next_arg:
 420                         i--;
 421                         arg++;
 422                 }
 423         }
 424
 425         /*
 426          * If you triggered the below warning, the trace event reported
 427          * uses an unsafe dereference pointer %p*. As the data stored
 428          * at the trace event time may no longer exist when the trace
 429          * event is printed, dereferencing to the original source is
 430          * unsafe. The source of the dereference must be copied into the
 431          * event itself, and the dereference must access the copy instead.
 432          */
 433         if (WARN_ON_ONCE(dereference_flags)) {
 434                 arg = 1;
 435                 while (!(dereference_flags & 1)) {
 436                         dereference_flags >>= 1;
 437                         arg++;
 438                 }
 439                 pr_warn("event %s has unsafe dereference of argument %d\n",
 440                         trace_event_name(call), arg);
 441                 pr_warn("print_fmt: %s\n", fmt);
 442         }
 443 }
 444
 445 int trace_event_raw_init(struct trace_event_call *call)
 446 {
 447         int id;
 448
 449         id = register_trace_event(&call->event);
 450         if (!id)
 451                 return -ENODEV;
 452
 453         test_event_printk(call);
 454
 455         return 0;
 456 }
 457 EXPORT_SYMBOL_GPL(trace_event_raw_init);
 458
 459 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
 460 {
 461         struct trace_array *tr = trace_file->tr;
 462         struct trace_array_cpu *data;
 463         struct trace_pid_list *no_pid_list;
 464         struct trace_pid_list *pid_list;
 465
 466         pid_list = rcu_dereference_raw(tr->filtered_pids);
 467         no_pid_list = rcu_dereference_raw(tr->filtered_no_pids);
 468
 469         if (!pid_list && !no_pid_list)
 470                 return false;
 471
 472         data = this_cpu_ptr(tr->array_buffer.data);
 473
 474         return data->ignore_pid;
 475 }
 476 EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
 477
 478 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 479                                  struct trace_event_file *trace_file,
 480                                  unsigned long len)
 481 {
 482         struct trace_event_call *event_call = trace_file->event_call;
 483
 484         if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
 485             trace_event_ignore_this_pid(trace_file))
 486                 return NULL;
 487
 488         /*
 489          * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
 490          * preemption (adding one to the preempt_count). Since we are
 491          * interested in the preempt_count at the time the tracepoint was
 492          * hit, we need to subtract one to offset the increment.
 493          */
 494         fbuffer->trace_ctx = tracing_gen_ctx_dec();
 495         fbuffer->trace_file = trace_file;
 496
 497         fbuffer->event =
 498                 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
 499                                                 event_call->event.type, len,
 500                                                 fbuffer->trace_ctx);
 501         if (!fbuffer->event)
 502                 return NULL;
 503
 504         fbuffer->regs = NULL;
 505         fbuffer->entry = ring_buffer_event_data(fbuffer->event);
 506         return fbuffer->entry;
 507 }
 508 EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
 509
 510 int trace_event_reg(struct trace_event_call *call,
 511                     enum trace_reg type, void *data)
 512 {
 513         struct trace_event_file *file = data;
 514
 515         WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
 516         switch (type) {
 517         case TRACE_REG_REGISTER:
 518                 return tracepoint_probe_register(call->tp,
 519                                                  call->class->probe,
 520                                                  file);
 521         case TRACE_REG_UNREGISTER:
 522                 tracepoint_probe_unregister(call->tp,
 523                                             call->class->probe,
 524                                             file);
 525                 return 0;
 526
 527 #ifdef CONFIG_PERF_EVENTS
 528         case TRACE_REG_PERF_REGISTER:
 529                 return tracepoint_probe_register(call->tp,
 530                                                  call->class->perf_probe,
 531                                                  call);
 532         case TRACE_REG_PERF_UNREGISTER:
 533                 tracepoint_probe_unregister(call->tp,
 534                                             call->class->perf_probe,
 535                                             call);
 536                 return 0;
 537         case TRACE_REG_PERF_OPEN:
 538         case TRACE_REG_PERF_CLOSE:
 539         case TRACE_REG_PERF_ADD:
 540         case TRACE_REG_PERF_DEL:
 541                 return 0;
 542 #endif
 543         }
 544         return 0;
 545 }
 546 EXPORT_SYMBOL_GPL(trace_event_reg);
 547
 548 void trace_event_enable_cmd_record(bool enable)
 549 {
 550         struct trace_event_file *file;
 551         struct trace_array *tr;
 552
 553         lockdep_assert_held(&event_mutex);
 554
 555         do_for_each_event_file(tr, file) {
 556
 557                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
 558                         continue;
 559
 560                 if (enable) {
 561                         tracing_start_cmdline_record();
 562                         set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 563                 } else {
 564                         tracing_stop_cmdline_record();
 565                         clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 566                 }
 567         } while_for_each_event_file();
 568 }
 569
 570 void trace_event_enable_tgid_record(bool enable)
 571 {
 572         struct trace_event_file *file;
 573         struct trace_array *tr;
 574
 575         lockdep_assert_held(&event_mutex);
 576
 577         do_for_each_event_file(tr, file) {
 578                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
 579                         continue;
 580
 581                 if (enable) {
 582                         tracing_start_tgid_record();
 583                         set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 584                 } else {
 585                         tracing_stop_tgid_record();
 586                         clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
 587                                   &file->flags);
 588                 }
 589         } while_for_each_event_file();
 590 }
 591
 592 static int __ftrace_event_enable_disable(struct trace_event_file *file,
 593                                          int enable, int soft_disable)
 594 {
 595         struct trace_event_call *call = file->event_call;
 596         struct trace_array *tr = file->tr;
 597         int ret = 0;
 598         int disable;
 599
 600         switch (enable) {
 601         case 0:
 602                 /*
 603                  * When soft_disable is set and enable is cleared, the sm_ref
 604                  * reference counter is decremented. If it reaches 0, we want
 605                  * to clear the SOFT_DISABLED flag but leave the event in the
 606                  * state that it was. That is, if the event was enabled and
 607                  * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
 608                  * is set we do not want the event to be enabled before we
 609                  * clear the bit.
 610                  *
 611                  * When soft_disable is not set but the SOFT_MODE flag is,
 612                  * we do nothing. Do not disable the tracepoint, otherwise
 613                  * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
 614                  */
 615                 if (soft_disable) {
 616                         if (atomic_dec_return(&file->sm_ref) > 0)
 617                                 break;
 618                         disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
 619                         clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 620                         /* Disable use of trace_buffered_event */
 621                         trace_buffered_event_disable();
 622                 } else
 623                         disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
 624
 625                 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
 626                         clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 627                         if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
 628                                 tracing_stop_cmdline_record();
 629                                 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 630                         }
 631
 632                         if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
 633                                 tracing_stop_tgid_record();
 634                                 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 635                         }
 636
 637                         call->class->reg(call, TRACE_REG_UNREGISTER, file);
 638                 }
 639                 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
 640                 if (file->flags & EVENT_FILE_FL_SOFT_MODE)
 641                         set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 642                 else
 643                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 644                 break;
 645         case 1:
 646                 /*
 647                  * When soft_disable is set and enable is set, we want to
 648                  * register the tracepoint for the event, but leave the event
 649                  * as is. That means, if the event was already enabled, we do
 650                  * nothing (but set SOFT_MODE). If the event is disabled, we
 651                  * set SOFT_DISABLED before enabling the event tracepoint, so
 652                  * it still seems to be disabled.
 653                  */
 654                 if (!soft_disable)
 655                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 656                 else {
 657                         if (atomic_inc_return(&file->sm_ref) > 1)
 658                                 break;
 659                         set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 660                         /* Enable use of trace_buffered_event */
 661                         trace_buffered_event_enable();
 662                 }
 663
 664                 if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
 665                         bool cmd = false, tgid = false;
 666
 667                         /* Keep the event disabled, when going to SOFT_MODE. */
 668                         if (soft_disable)
 669                                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 670
 671                         if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
 672                                 cmd = true;
 673                                 tracing_start_cmdline_record();
 674                                 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 675                         }
 676
 677                         if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
 678                                 tgid = true;
 679                                 tracing_start_tgid_record();
 680                                 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 681                         }
 682
 683                         ret = call->class->reg(call, TRACE_REG_REGISTER, file);
 684                         if (ret) {
 685                                 if (cmd)
 686                                         tracing_stop_cmdline_record();
 687                                 if (tgid)
 688                                         tracing_stop_tgid_record();
 689                                 pr_info("event trace: Could not enable event "
 690                                         "%s\n", trace_event_name(call));
 691                                 break;
 692                         }
 693                         set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 694
 695                         /* WAS_ENABLED gets set but never cleared. */
 696                         set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
 697                 }
 698                 break;
 699         }
 700
 701         return ret;
 702 }
 703
 704 int trace_event_enable_disable(struct trace_event_file *file,
 705                                int enable, int soft_disable)
 706 {
 707         return __ftrace_event_enable_disable(file, enable, soft_disable);
 708 }
 709
 710 static int ftrace_event_enable_disable(struct trace_event_file *file,
 711                                        int enable)
 712 {
 713         return __ftrace_event_enable_disable(file, enable, 0);
 714 }
 715
 716 static void ftrace_clear_events(struct trace_array *tr)
 717 {
 718         struct trace_event_file *file;
 719
 720         mutex_lock(&event_mutex);
 721         list_for_each_entry(file, &tr->events, list) {
 722                 ftrace_event_enable_disable(file, 0);
 723         }
 724         mutex_unlock(&event_mutex);
 725 }
 726
 727 static void
 728 event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
 729 {
 730         struct trace_pid_list *pid_list;
 731         struct trace_array *tr = data;
 732
 733         pid_list = rcu_dereference_raw(tr->filtered_pids);
 734         trace_filter_add_remove_task(pid_list, NULL, task);
 735
 736         pid_list = rcu_dereference_raw(tr->filtered_no_pids);
 737         trace_filter_add_remove_task(pid_list, NULL, task);
 738 }
 739
 740 static void
 741 event_filter_pid_sched_process_fork(void *data,
 742                                     struct task_struct *self,
 743                                     struct task_struct *task)
 744 {
 745         struct trace_pid_list *pid_list;
 746         struct trace_array *tr = data;
 747
 748         pid_list = rcu_dereference_sched(tr->filtered_pids);
 749         trace_filter_add_remove_task(pid_list, self, task);
 750
 751         pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 752         trace_filter_add_remove_task(pid_list, self, task);
 753 }
 754
 755 void trace_event_follow_fork(struct trace_array *tr, bool enable)
 756 {
 757         if (enable) {
 758                 register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
 759                                                        tr, INT_MIN);
 760                 register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
 761                                                        tr, INT_MAX);
 762         } else {
 763                 unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
 764                                                     tr);
 765                 unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
 766                                                     tr);
 767         }
 768 }
 769
 770 static void
 771 event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
 772                     struct task_struct *prev, struct task_struct *next)
 773 {
 774         struct trace_array *tr = data;
 775         struct trace_pid_list *no_pid_list;
 776         struct trace_pid_list *pid_list;
 777         bool ret;
 778
 779         pid_list = rcu_dereference_sched(tr->filtered_pids);
 780         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 781
 782         /*
 783          * Sched switch is funny, as we only want to ignore it
 784          * in the notrace case if both prev and next should be ignored.
 785          */
 786         ret = trace_ignore_this_task(NULL, no_pid_list, prev) &&
 787                 trace_ignore_this_task(NULL, no_pid_list, next);
 788
 789         this_cpu_write(tr->array_buffer.data->ignore_pid, ret ||
 790                        (trace_ignore_this_task(pid_list, NULL, prev) &&
 791                         trace_ignore_this_task(pid_list, NULL, next)));
 792 }
 793
 794 static void
 795 event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
 796                     struct task_struct *prev, struct task_struct *next)
 797 {
 798         struct trace_array *tr = data;
 799         struct trace_pid_list *no_pid_list;
 800         struct trace_pid_list *pid_list;
 801
 802         pid_list = rcu_dereference_sched(tr->filtered_pids);
 803         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 804
 805         this_cpu_write(tr->array_buffer.data->ignore_pid,
 806                        trace_ignore_this_task(pid_list, no_pid_list, next));
 807 }
 808
 809 static void
 810 event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
 811 {
 812         struct trace_array *tr = data;
 813         struct trace_pid_list *no_pid_list;
 814         struct trace_pid_list *pid_list;
 815
 816         /* Nothing to do if we are already tracing */
 817         if (!this_cpu_read(tr->array_buffer.data->ignore_pid))
 818                 return;
 819
 820         pid_list = rcu_dereference_sched(tr->filtered_pids);
 821         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 822
 823         this_cpu_write(tr->array_buffer.data->ignore_pid,
 824                        trace_ignore_this_task(pid_list, no_pid_list, task));
 825 }
 826
 827 static void
 828 event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
 829 {
 830         struct trace_array *tr = data;
 831         struct trace_pid_list *no_pid_list;
 832         struct trace_pid_list *pid_list;
 833
 834         /* Nothing to do if we are not tracing */
 835         if (this_cpu_read(tr->array_buffer.data->ignore_pid))
 836                 return;
 837
 838         pid_list = rcu_dereference_sched(tr->filtered_pids);
 839         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 840
 841         /* Set tracing if current is enabled */
 842         this_cpu_write(tr->array_buffer.data->ignore_pid,
 843                        trace_ignore_this_task(pid_list, no_pid_list, current));
 844 }
 845
 846 static void unregister_pid_events(struct trace_array *tr)
 847 {
 848         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
 849         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
 850
 851         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
 852         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
 853
 854         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
 855         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
 856
 857         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
 858         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
 859 }
 860
 861 static void __ftrace_clear_event_pids(struct trace_array *tr, int type)
 862 {
 863         struct trace_pid_list *pid_list;
 864         struct trace_pid_list *no_pid_list;
 865         struct trace_event_file *file;
 866         int cpu;
 867
 868         pid_list = rcu_dereference_protected(tr->filtered_pids,
 869                                              lockdep_is_held(&event_mutex));
 870         no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
 871                                              lockdep_is_held(&event_mutex));
 872
 873         /* Make sure there's something to do */
 874         if (!pid_type_enabled(type, pid_list, no_pid_list))
 875                 return;
 876
 877         if (!still_need_pid_events(type, pid_list, no_pid_list)) {
 878                 unregister_pid_events(tr);
 879
 880                 list_for_each_entry(file, &tr->events, list) {
 881                         clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
 882                 }
 883
 884                 for_each_possible_cpu(cpu)
 885                         per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
 886         }
 887
 888         if (type & TRACE_PIDS)
 889                 rcu_assign_pointer(tr->filtered_pids, NULL);
 890
 891         if (type & TRACE_NO_PIDS)
 892                 rcu_assign_pointer(tr->filtered_no_pids, NULL);
 893
 894         /* Wait till all users are no longer using pid filtering */
 895         tracepoint_synchronize_unregister();
 896
 897         if ((type & TRACE_PIDS) && pid_list)
 898                 trace_pid_list_free(pid_list);
 899
 900         if ((type & TRACE_NO_PIDS) && no_pid_list)
 901                 trace_pid_list_free(no_pid_list);
 902 }
 903
 904 static void ftrace_clear_event_pids(struct trace_array *tr, int type)
 905 {
 906         mutex_lock(&event_mutex);
 907         __ftrace_clear_event_pids(tr, type);
 908         mutex_unlock(&event_mutex);
 909 }
 910
 911 static void __put_system(struct event_subsystem *system)
 912 {
 913         struct event_filter *filter = system->filter;
 914
 915         WARN_ON_ONCE(system_refcount(system) == 0);
 916         if (system_refcount_dec(system))
 917                 return;
 918
 919         list_del(&system->list);
 920
 921         if (filter) {
 922                 kfree(filter->filter_string);
 923                 kfree(filter);
 924         }
 925         kfree_const(system->name);
 926         kfree(system);
 927 }
 928
 929 static void __get_system(struct event_subsystem *system)
 930 {
 931         WARN_ON_ONCE(system_refcount(system) == 0);
 932         system_refcount_inc(system);
 933 }
 934
 935 static void __get_system_dir(struct trace_subsystem_dir *dir)
 936 {
 937         WARN_ON_ONCE(dir->ref_count == 0);
 938         dir->ref_count++;
 939         __get_system(dir->subsystem);
 940 }
 941
 942 static void __put_system_dir(struct trace_subsystem_dir *dir)
 943 {
 944         WARN_ON_ONCE(dir->ref_count == 0);
 945         /* If the subsystem is about to be freed, the dir must be too */
 946         WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
 947
 948         __put_system(dir->subsystem);
 949         if (!--dir->ref_count)
 950                 kfree(dir);
 951 }
 952
 953 static void put_system(struct trace_subsystem_dir *dir)
 954 {
 955         mutex_lock(&event_mutex);
 956         __put_system_dir(dir);
 957         mutex_unlock(&event_mutex);
 958 }
 959
 960 static void remove_subsystem(struct trace_subsystem_dir *dir)
 961 {
 962         if (!dir)
 963                 return;
 964
 965         if (!--dir->nr_events) {
 966                 tracefs_remove(dir->entry);
 967                 list_del(&dir->list);
 968                 __put_system_dir(dir);
 969         }
 970 }
 971
 972 static void remove_event_file_dir(struct trace_event_file *file)
 973 {
 974         struct dentry *dir = file->dir;
 975         struct dentry *child;
 976
 977         if (dir) {
 978                 spin_lock(&dir->d_lock);        /* probably unneeded */
 979                 list_for_each_entry(child, &dir->d_subdirs, d_child) {
 980                         if (d_really_is_positive(child))        /* probably unneeded */
 981                                 d_inode(child)->i_private = NULL;
 982                 }
 983                 spin_unlock(&dir->d_lock);
 984
 985                 tracefs_remove(dir);
 986         }
 987
 988         list_del(&file->list);
 989         remove_subsystem(file->system);
 990         free_event_filter(file->filter);
 991         kmem_cache_free(file_cachep, file);
 992 }
 993
 994 /*
 995  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
 996  */
 997 static int
 998 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
 999                               const char *sub, const char *event, int set)
1000 {
1001         struct trace_event_file *file;
1002         struct trace_event_call *call;
1003         const char *name;
1004         int ret = -EINVAL;
1005         int eret = 0;
1006
1007         list_for_each_entry(file, &tr->events, list) {
1008
1009                 call = file->event_call;
1010                 name = trace_event_name(call);
1011
1012                 if (!name || !call->class || !call->class->reg)
1013                         continue;
1014
1015                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1016                         continue;
1017
1018                 if (match &&
1019                     strcmp(match, name) != 0 &&
1020                     strcmp(match, call->class->system) != 0)
1021                         continue;
1022
1023                 if (sub && strcmp(sub, call->class->system) != 0)
1024                         continue;
1025
1026                 if (event && strcmp(event, name) != 0)
1027                         continue;
1028
1029                 ret = ftrace_event_enable_disable(file, set);
1030
1031                 /*
1032                  * Save the first error and return that. Some events
1033                  * may still have been enabled, but let the user
1034                  * know that something went wrong.
1035                  */
1036                 if (ret && !eret)
1037                         eret = ret;
1038
1039                 ret = eret;
1040         }
1041
1042         return ret;
1043 }
1044
1045 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
1046                                   const char *sub, const char *event, int set)
1047 {
1048         int ret;
1049
1050         mutex_lock(&event_mutex);
1051         ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
1052         mutex_unlock(&event_mutex);
1053
1054         return ret;
1055 }
1056
1057 int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
1058 {
1059         char *event = NULL, *sub = NULL, *match;
1060         int ret;
1061
1062         if (!tr)
1063                 return -ENOENT;
1064         /*
1065          * The buf format can be <subsystem>:<event-name>
1066          *  *:<event-name> means any event by that name.
1067          *  :<event-name> is the same.
1068          *
1069          *  <subsystem>:* means all events in that subsystem
1070          *  <subsystem>: means the same.
1071          *
1072          *  <name> (no ':') means all events in a subsystem with
1073          *  the name <name> or any event that matches <name>
1074          */
1075
1076         match = strsep(&buf, ":");
1077         if (buf) {
1078                 sub = match;
1079                 event = buf;
1080                 match = NULL;
1081
1082                 if (!strlen(sub) || strcmp(sub, "*") == 0)
1083                         sub = NULL;
1084                 if (!strlen(event) || strcmp(event, "*") == 0)
1085                         event = NULL;
1086         }
1087
1088         ret = __ftrace_set_clr_event(tr, match, sub, event, set);
1089
1090         /* Put back the colon to allow this to be called again */
1091         if (buf)
1092                 *(buf - 1) = ':';
1093
1094         return ret;
1095 }
1096
1097 /**
1098  * trace_set_clr_event - enable or disable an event
1099  * @system: system name to match (NULL for any system)
1100  * @event: event name to match (NULL for all events, within system)
1101  * @set: 1 to enable, 0 to disable
1102  *
1103  * This is a way for other parts of the kernel to enable or disable
1104  * event recording.
1105  *
1106  * Returns 0 on success, -EINVAL if the parameters do not match any
1107  * registered events.
1108  */
1109 int trace_set_clr_event(const char *system, const char *event, int set)
1110 {
1111         struct trace_array *tr = top_trace_array();
1112
1113         if (!tr)
1114                 return -ENODEV;
1115
1116         return __ftrace_set_clr_event(tr, NULL, system, event, set);
1117 }
1118 EXPORT_SYMBOL_GPL(trace_set_clr_event);
1119
1120 /**
1121  * trace_array_set_clr_event - enable or disable an event for a trace array.
1122  * @tr: concerned trace array.
1123  * @system: system name to match (NULL for any system)
1124  * @event: event name to match (NULL for all events, within system)
1125  * @enable: true to enable, false to disable
1126  *
1127  * This is a way for other parts of the kernel to enable or disable
1128  * event recording.
1129  *
1130  * Returns 0 on success, -EINVAL if the parameters do not match any
1131  * registered events.
1132  */
1133 int trace_array_set_clr_event(struct trace_array *tr, const char *system,
1134                 const char *event, bool enable)
1135 {
1136         int set;
1137
1138         if (!tr)
1139                 return -ENOENT;
1140
1141         set = (enable == true) ? 1 : 0;
1142         return __ftrace_set_clr_event(tr, NULL, system, event, set);
1143 }
1144 EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
1145
1146 /* 128 should be much more than enough */
1147 #define EVENT_BUF_SIZE          127
1148
1149 static ssize_t
1150 ftrace_event_write(struct file *file, const char __user *ubuf,
1151                    size_t cnt, loff_t *ppos)
1152 {
1153         struct trace_parser parser;
1154         struct seq_file *m = file->private_data;
1155         struct trace_array *tr = m->private;
1156         ssize_t read, ret;
1157
1158         if (!cnt)
1159                 return 0;
1160
1161         ret = tracing_update_buffers();
1162         if (ret < 0)
1163                 return ret;
1164
1165         if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
1166                 return -ENOMEM;
1167
1168         read = trace_get_user(&parser, ubuf, cnt, ppos);
1169
1170         if (read >= 0 && trace_parser_loaded((&parser))) {
1171                 int set = 1;
1172
1173                 if (*parser.buffer == '!')
1174                         set = 0;
1175
1176                 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
1177                 if (ret)
1178                         goto out_put;
1179         }
1180
1181         ret = read;
1182
1183  out_put:
1184         trace_parser_put(&parser);
1185
1186         return ret;
1187 }
1188
1189 static void *
1190 t_next(struct seq_file *m, void *v, loff_t *pos)
1191 {
1192         struct trace_event_file *file = v;
1193         struct trace_event_call *call;
1194         struct trace_array *tr = m->private;
1195
1196         (*pos)++;
1197
1198         list_for_each_entry_continue(file, &tr->events, list) {
1199                 call = file->event_call;
1200                 /*
1201                  * The ftrace subsystem is for showing formats only.
1202                  * They can not be enabled or disabled via the event files.
1203                  */
1204                 if (call->class && call->class->reg &&
1205                     !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1206                         return file;
1207         }
1208
1209         return NULL;
1210 }
1211
1212 static void *t_start(struct seq_file *m, loff_t *pos)
1213 {
1214         struct trace_event_file *file;
1215         struct trace_array *tr = m->private;
1216         loff_t l;
1217
1218         mutex_lock(&event_mutex);
1219
1220         file = list_entry(&tr->events, struct trace_event_file, list);
1221         for (l = 0; l <= *pos; ) {
1222                 file = t_next(m, file, &l);
1223                 if (!file)
1224                         break;
1225         }
1226         return file;
1227 }
1228
1229 static void *
1230 s_next(struct seq_file *m, void *v, loff_t *pos)
1231 {
1232         struct trace_event_file *file = v;
1233         struct trace_array *tr = m->private;
1234
1235         (*pos)++;
1236
1237         list_for_each_entry_continue(file, &tr->events, list) {
1238                 if (file->flags & EVENT_FILE_FL_ENABLED)
1239                         return file;
1240         }
1241
1242         return NULL;
1243 }
1244
1245 static void *s_start(struct seq_file *m, loff_t *pos)
1246 {
1247         struct trace_event_file *file;
1248         struct trace_array *tr = m->private;
1249         loff_t l;
1250
1251         mutex_lock(&event_mutex);
1252
1253         file = list_entry(&tr->events, struct trace_event_file, list);
1254         for (l = 0; l <= *pos; ) {
1255                 file = s_next(m, file, &l);
1256                 if (!file)
1257                         break;
1258         }
1259         return file;
1260 }
1261
1262 static int t_show(struct seq_file *m, void *v)
1263 {
1264         struct trace_event_file *file = v;
1265         struct trace_event_call *call = file->event_call;
1266
1267         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1268                 seq_printf(m, "%s:", call->class->system);
1269         seq_printf(m, "%s\n", trace_event_name(call));
1270
1271         return 0;
1272 }
1273
1274 static void t_stop(struct seq_file *m, void *p)
1275 {
1276         mutex_unlock(&event_mutex);
1277 }
1278
1279 static void *
1280 __next(struct seq_file *m, void *v, loff_t *pos, int type)
1281 {
1282         struct trace_array *tr = m->private;
1283         struct trace_pid_list *pid_list;
1284
1285         if (type == TRACE_PIDS)
1286                 pid_list = rcu_dereference_sched(tr->filtered_pids);
1287         else
1288                 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1289
1290         return trace_pid_next(pid_list, v, pos);
1291 }
1292
1293 static void *
1294 p_next(struct seq_file *m, void *v, loff_t *pos)
1295 {
1296         return __next(m, v, pos, TRACE_PIDS);
1297 }
1298
1299 static void *
1300 np_next(struct seq_file *m, void *v, loff_t *pos)
1301 {
1302         return __next(m, v, pos, TRACE_NO_PIDS);
1303 }
1304
1305 static void *__start(struct seq_file *m, loff_t *pos, int type)
1306         __acquires(RCU)
1307 {
1308         struct trace_pid_list *pid_list;
1309         struct trace_array *tr = m->private;
1310
1311         /*
1312          * Grab the mutex, to keep calls to p_next() having the same
1313          * tr->filtered_pids as p_start() has.
1314          * If we just passed the tr->filtered_pids around, then RCU would
1315          * have been enough, but doing that makes things more complex.
1316          */
1317         mutex_lock(&event_mutex);
1318         rcu_read_lock_sched();
1319
1320         if (type == TRACE_PIDS)
1321                 pid_list = rcu_dereference_sched(tr->filtered_pids);
1322         else
1323                 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1324
1325         if (!pid_list)
1326                 return NULL;
1327
1328         return trace_pid_start(pid_list, pos);
1329 }
1330
1331 static void *p_start(struct seq_file *m, loff_t *pos)
1332         __acquires(RCU)
1333 {
1334         return __start(m, pos, TRACE_PIDS);
1335 }
1336
1337 static void *np_start(struct seq_file *m, loff_t *pos)
1338         __acquires(RCU)
1339 {
1340         return __start(m, pos, TRACE_NO_PIDS);
1341 }
1342
1343 static void p_stop(struct seq_file *m, void *p)
1344         __releases(RCU)
1345 {
1346         rcu_read_unlock_sched();
1347         mutex_unlock(&event_mutex);
1348 }
1349
1350 static ssize_t
1351 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1352                   loff_t *ppos)
1353 {
1354         struct trace_event_file *file;
1355         unsigned long flags;
1356         char buf[4] = "0";
1357
1358         mutex_lock(&event_mutex);
1359         file = event_file_data(filp);
1360         if (likely(file))
1361                 flags = file->flags;
1362         mutex_unlock(&event_mutex);
1363
1364         if (!file)
1365                 return -ENODEV;
1366
1367         if (flags & EVENT_FILE_FL_ENABLED &&
1368             !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1369                 strcpy(buf, "1");
1370
1371         if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1372             flags & EVENT_FILE_FL_SOFT_MODE)
1373                 strcat(buf, "*");
1374
1375         strcat(buf, "\n");
1376
1377         return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1378 }
1379
1380 static ssize_t
1381 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1382                    loff_t *ppos)
1383 {
1384         struct trace_event_file *file;
1385         unsigned long val;
1386         int ret;
1387
1388         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1389         if (ret)
1390                 return ret;
1391
1392         ret = tracing_update_buffers();
1393         if (ret < 0)
1394                 return ret;
1395
1396         switch (val) {
1397         case 0:
1398         case 1:
1399                 ret = -ENODEV;
1400                 mutex_lock(&event_mutex);
1401                 file = event_file_data(filp);
1402                 if (likely(file))
1403                         ret = ftrace_event_enable_disable(file, val);
1404                 mutex_unlock(&event_mutex);
1405                 break;
1406
1407         default:
1408                 return -EINVAL;
1409         }
1410
1411         *ppos += cnt;
1412
1413         return ret ? ret : cnt;
1414 }
1415
1416 static ssize_t
1417 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1418                    loff_t *ppos)
1419 {
1420         const char set_to_char[4] = { '?', '0', '1', 'X' };
1421         struct trace_subsystem_dir *dir = filp->private_data;
1422         struct event_subsystem *system = dir->subsystem;
1423         struct trace_event_call *call;
1424         struct trace_event_file *file;
1425         struct trace_array *tr = dir->tr;
1426         char buf[2];
1427         int set = 0;
1428         int ret;
1429
1430         mutex_lock(&event_mutex);
1431         list_for_each_entry(file, &tr->events, list) {
1432                 call = file->event_call;
1433                 if ((call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
1434                     !trace_event_name(call) || !call->class || !call->class->reg)
1435                         continue;
1436
1437                 if (system && strcmp(call->class->system, system->name) != 0)
1438                         continue;
1439
1440                 /*
1441                  * We need to find out if all the events are set
1442                  * or if all events or cleared, or if we have
1443                  * a mixture.
1444                  */
1445                 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1446
1447                 /*
1448                  * If we have a mixture, no need to look further.
1449                  */
1450                 if (set == 3)
1451                         break;
1452         }
1453         mutex_unlock(&event_mutex);
1454
1455         buf[0] = set_to_char[set];
1456         buf[1] = '\n';
1457
1458         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1459
1460         return ret;
1461 }
1462
1463 static ssize_t
1464 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1465                     loff_t *ppos)
1466 {
1467         struct trace_subsystem_dir *dir = filp->private_data;
1468         struct event_subsystem *system = dir->subsystem;
1469         const char *name = NULL;
1470         unsigned long val;
1471         ssize_t ret;
1472
1473         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1474         if (ret)
1475                 return ret;
1476
1477         ret = tracing_update_buffers();
1478         if (ret < 0)
1479                 return ret;
1480
1481         if (val != 0 && val != 1)
1482                 return -EINVAL;
1483
1484         /*
1485          * Opening of "enable" adds a ref count to system,
1486          * so the name is safe to use.
1487          */
1488         if (system)
1489                 name = system->name;
1490
1491         ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1492         if (ret)
1493                 goto out;
1494
1495         ret = cnt;
1496
1497 out:
1498         *ppos += cnt;
1499
1500         return ret;
1501 }
1502
1503 enum {
1504         FORMAT_HEADER           = 1,
1505         FORMAT_FIELD_SEPERATOR  = 2,
1506         FORMAT_PRINTFMT         = 3,
1507 };
1508
1509 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1510 {
1511         struct trace_event_call *call = event_file_data(m->private);
1512         struct list_head *common_head = &ftrace_common_fields;
1513         struct list_head *head = trace_get_fields(call);
1514         struct list_head *node = v;
1515
1516         (*pos)++;
1517
1518         switch ((unsigned long)v) {
1519         case FORMAT_HEADER:
1520                 node = common_head;
1521                 break;
1522
1523         case FORMAT_FIELD_SEPERATOR:
1524                 node = head;
1525                 break;
1526
1527         case FORMAT_PRINTFMT:
1528                 /* all done */
1529                 return NULL;
1530         }
1531
1532         node = node->prev;
1533         if (node == common_head)
1534                 return (void *)FORMAT_FIELD_SEPERATOR;
1535         else if (node == head)
1536                 return (void *)FORMAT_PRINTFMT;
1537         else
1538                 return node;
1539 }
1540
1541 static int f_show(struct seq_file *m, void *v)
1542 {
1543         struct trace_event_call *call = event_file_data(m->private);
1544         struct ftrace_event_field *field;
1545         const char *array_descriptor;
1546
1547         switch ((unsigned long)v) {
1548         case FORMAT_HEADER:
1549                 seq_printf(m, "name: %s\n", trace_event_name(call));
1550                 seq_printf(m, "ID: %d\n", call->event.type);
1551                 seq_puts(m, "format:\n");
1552                 return 0;
1553
1554         case FORMAT_FIELD_SEPERATOR:
1555                 seq_putc(m, '\n');
1556                 return 0;
1557
1558         case FORMAT_PRINTFMT:
1559                 seq_printf(m, "\nprint fmt: %s\n",
1560                            call->print_fmt);
1561                 return 0;
1562         }
1563
1564         field = list_entry(v, struct ftrace_event_field, link);
1565         /*
1566          * Smartly shows the array type(except dynamic array).
1567          * Normal:
1568          *      field:TYPE VAR
1569          * If TYPE := TYPE[LEN], it is shown:
1570          *      field:TYPE VAR[LEN]
1571          */
1572         array_descriptor = strchr(field->type, '[');
1573
1574         if (str_has_prefix(field->type, "__data_loc"))
1575                 array_descriptor = NULL;
1576
1577         if (!array_descriptor)
1578                 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1579                            field->type, field->name, field->offset,
1580                            field->size, !!field->is_signed);
1581         else
1582                 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1583                            (int)(array_descriptor - field->type),
1584                            field->type, field->name,
1585                            array_descriptor, field->offset,
1586                            field->size, !!field->is_signed);
1587
1588         return 0;
1589 }
1590
1591 static void *f_start(struct seq_file *m, loff_t *pos)
1592 {
1593         void *p = (void *)FORMAT_HEADER;
1594         loff_t l = 0;
1595
1596         /* ->stop() is called even if ->start() fails */
1597         mutex_lock(&event_mutex);
1598         if (!event_file_data(m->private))
1599                 return ERR_PTR(-ENODEV);
1600
1601         while (l < *pos && p)
1602                 p = f_next(m, p, &l);
1603
1604         return p;
1605 }
1606
1607 static void f_stop(struct seq_file *m, void *p)
1608 {
1609         mutex_unlock(&event_mutex);
1610 }
1611
1612 static const struct seq_operations trace_format_seq_ops = {
1613         .start          = f_start,
1614         .next           = f_next,
1615         .stop           = f_stop,
1616         .show           = f_show,
1617 };
1618
1619 static int trace_format_open(struct inode *inode, struct file *file)
1620 {
1621         struct seq_file *m;
1622         int ret;
1623
1624         /* Do we want to hide event format files on tracefs lockdown? */
1625
1626         ret = seq_open(file, &trace_format_seq_ops);
1627         if (ret < 0)
1628                 return ret;
1629
1630         m = file->private_data;
1631         m->private = file;
1632
1633         return 0;
1634 }
1635
1636 static ssize_t
1637 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1638 {
1639         int id = (long)event_file_data(filp);
1640         char buf[32];
1641         int len;
1642
1643         if (unlikely(!id))
1644                 return -ENODEV;
1645
1646         len = sprintf(buf, "%d\n", id);
1647
1648         return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1649 }
1650
1651 static ssize_t
1652 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1653                   loff_t *ppos)
1654 {
1655         struct trace_event_file *file;
1656         struct trace_seq *s;
1657         int r = -ENODEV;
1658
1659         if (*ppos)
1660                 return 0;
1661
1662         s = kmalloc(sizeof(*s), GFP_KERNEL);
1663
1664         if (!s)
1665                 return -ENOMEM;
1666
1667         trace_seq_init(s);
1668
1669         mutex_lock(&event_mutex);
1670         file = event_file_data(filp);
1671         if (file)
1672                 print_event_filter(file, s);
1673         mutex_unlock(&event_mutex);
1674
1675         if (file)
1676                 r = simple_read_from_buffer(ubuf, cnt, ppos,
1677                                             s->buffer, trace_seq_used(s));
1678
1679         kfree(s);
1680
1681         return r;
1682 }
1683
1684 static ssize_t
1685 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1686                    loff_t *ppos)
1687 {
1688         struct trace_event_file *file;
1689         char *buf;
1690         int err = -ENODEV;
1691
1692         if (cnt >= PAGE_SIZE)
1693                 return -EINVAL;
1694
1695         buf = memdup_user_nul(ubuf, cnt);
1696         if (IS_ERR(buf))
1697                 return PTR_ERR(buf);
1698
1699         mutex_lock(&event_mutex);
1700         file = event_file_data(filp);
1701         if (file)
1702                 err = apply_event_filter(file, buf);
1703         mutex_unlock(&event_mutex);
1704
1705         kfree(buf);
1706         if (err < 0)
1707                 return err;
1708
1709         *ppos += cnt;
1710
1711         return cnt;
1712 }
1713
1714 static LIST_HEAD(event_subsystems);
1715
1716 static int subsystem_open(struct inode *inode, struct file *filp)
1717 {
1718         struct event_subsystem *system = NULL;
1719         struct trace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1720         struct trace_array *tr;
1721         int ret;
1722
1723         if (tracing_is_disabled())
1724                 return -ENODEV;
1725
1726         /* Make sure the system still exists */
1727         mutex_lock(&event_mutex);
1728         mutex_lock(&trace_types_lock);
1729         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1730                 list_for_each_entry(dir, &tr->systems, list) {
1731                         if (dir == inode->i_private) {
1732                                 /* Don't open systems with no events */
1733                                 if (dir->nr_events) {
1734                                         __get_system_dir(dir);
1735                                         system = dir->subsystem;
1736                                 }
1737                                 goto exit_loop;
1738                         }
1739                 }
1740         }
1741  exit_loop:
1742         mutex_unlock(&trace_types_lock);
1743         mutex_unlock(&event_mutex);
1744
1745         if (!system)
1746                 return -ENODEV;
1747
1748         /* Some versions of gcc think dir can be uninitialized here */
1749         WARN_ON(!dir);
1750
1751         /* Still need to increment the ref count of the system */
1752         if (trace_array_get(tr) < 0) {
1753                 put_system(dir);
1754                 return -ENODEV;
1755         }
1756
1757         ret = tracing_open_generic(inode, filp);
1758         if (ret < 0) {
1759                 trace_array_put(tr);
1760                 put_system(dir);
1761         }
1762
1763         return ret;
1764 }
1765
1766 static int system_tr_open(struct inode *inode, struct file *filp)
1767 {
1768         struct trace_subsystem_dir *dir;
1769         struct trace_array *tr = inode->i_private;
1770         int ret;
1771
1772         /* Make a temporary dir that has no system but points to tr */
1773         dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1774         if (!dir)
1775                 return -ENOMEM;
1776
1777         ret = tracing_open_generic_tr(inode, filp);
1778         if (ret < 0) {
1779                 kfree(dir);
1780                 return ret;
1781         }
1782         dir->tr = tr;
1783         filp->private_data = dir;
1784
1785         return 0;
1786 }
1787
1788 static int subsystem_release(struct inode *inode, struct file *file)
1789 {
1790         struct trace_subsystem_dir *dir = file->private_data;
1791
1792         trace_array_put(dir->tr);
1793
1794         /*
1795          * If dir->subsystem is NULL, then this is a temporary
1796          * descriptor that was made for a trace_array to enable
1797          * all subsystems.
1798          */
1799         if (dir->subsystem)
1800                 put_system(dir);
1801         else
1802                 kfree(dir);
1803
1804         return 0;
1805 }
1806
1807 static ssize_t
1808 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1809                       loff_t *ppos)
1810 {
1811         struct trace_subsystem_dir *dir = filp->private_data;
1812         struct event_subsystem *system = dir->subsystem;
1813         struct trace_seq *s;
1814         int r;
1815
1816         if (*ppos)
1817                 return 0;
1818
1819         s = kmalloc(sizeof(*s), GFP_KERNEL);
1820         if (!s)
1821                 return -ENOMEM;
1822
1823         trace_seq_init(s);
1824
1825         print_subsystem_event_filter(system, s);
1826         r = simple_read_from_buffer(ubuf, cnt, ppos,
1827                                     s->buffer, trace_seq_used(s));
1828
1829         kfree(s);
1830
1831         return r;
1832 }
1833
1834 static ssize_t
1835 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1836                        loff_t *ppos)
1837 {
1838         struct trace_subsystem_dir *dir = filp->private_data;
1839         char *buf;
1840         int err;
1841
1842         if (cnt >= PAGE_SIZE)
1843                 return -EINVAL;
1844
1845         buf = memdup_user_nul(ubuf, cnt);
1846         if (IS_ERR(buf))
1847                 return PTR_ERR(buf);
1848
1849         err = apply_subsystem_event_filter(dir, buf);
1850         kfree(buf);
1851         if (err < 0)
1852                 return err;
1853
1854         *ppos += cnt;
1855
1856         return cnt;
1857 }
1858
1859 static ssize_t
1860 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1861 {
1862         int (*func)(struct trace_seq *s) = filp->private_data;
1863         struct trace_seq *s;
1864         int r;
1865
1866         if (*ppos)
1867                 return 0;
1868
1869         s = kmalloc(sizeof(*s), GFP_KERNEL);
1870         if (!s)
1871                 return -ENOMEM;
1872
1873         trace_seq_init(s);
1874
1875         func(s);
1876         r = simple_read_from_buffer(ubuf, cnt, ppos,
1877                                     s->buffer, trace_seq_used(s));
1878
1879         kfree(s);
1880
1881         return r;
1882 }
1883
1884 static void ignore_task_cpu(void *data)
1885 {
1886         struct trace_array *tr = data;
1887         struct trace_pid_list *pid_list;
1888         struct trace_pid_list *no_pid_list;
1889
1890         /*
1891          * This function is called by on_each_cpu() while the
1892          * event_mutex is held.
1893          */
1894         pid_list = rcu_dereference_protected(tr->filtered_pids,
1895                                              mutex_is_locked(&event_mutex));
1896         no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
1897                                              mutex_is_locked(&event_mutex));
1898
1899         this_cpu_write(tr->array_buffer.data->ignore_pid,
1900                        trace_ignore_this_task(pid_list, no_pid_list, current));
1901 }
1902
1903 static void register_pid_events(struct trace_array *tr)
1904 {
1905         /*
1906          * Register a probe that is called before all other probes
1907          * to set ignore_pid if next or prev do not match.
1908          * Register a probe this is called after all other probes
1909          * to only keep ignore_pid set if next pid matches.
1910          */
1911         register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1912                                          tr, INT_MAX);
1913         register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1914                                          tr, 0);
1915
1916         register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1917                                          tr, INT_MAX);
1918         register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1919                                          tr, 0);
1920
1921         register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1922                                              tr, INT_MAX);
1923         register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1924                                              tr, 0);
1925
1926         register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1927                                          tr, INT_MAX);
1928         register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1929                                          tr, 0);
1930 }
1931
1932 static ssize_t
1933 event_pid_write(struct file *filp, const char __user *ubuf,
1934                 size_t cnt, loff_t *ppos, int type)
1935 {
1936         struct seq_file *m = filp->private_data;
1937         struct trace_array *tr = m->private;
1938         struct trace_pid_list *filtered_pids = NULL;
1939         struct trace_pid_list *other_pids = NULL;
1940         struct trace_pid_list *pid_list;
1941         struct trace_event_file *file;
1942         ssize_t ret;
1943
1944         if (!cnt)
1945                 return 0;
1946
1947         ret = tracing_update_buffers();
1948         if (ret < 0)
1949                 return ret;
1950
1951         mutex_lock(&event_mutex);
1952
1953         if (type == TRACE_PIDS) {
1954                 filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1955                                                           lockdep_is_held(&event_mutex));
1956                 other_pids = rcu_dereference_protected(tr->filtered_no_pids,
1957                                                           lockdep_is_held(&event_mutex));
1958         } else {
1959                 filtered_pids = rcu_dereference_protected(tr->filtered_no_pids,
1960                                                           lockdep_is_held(&event_mutex));
1961                 other_pids = rcu_dereference_protected(tr->filtered_pids,
1962                                                           lockdep_is_held(&event_mutex));
1963         }
1964
1965         ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
1966         if (ret < 0)
1967                 goto out;
1968
1969         if (type == TRACE_PIDS)
1970                 rcu_assign_pointer(tr->filtered_pids, pid_list);
1971         else
1972                 rcu_assign_pointer(tr->filtered_no_pids, pid_list);
1973
1974         list_for_each_entry(file, &tr->events, list) {
1975                 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
1976         }
1977
1978         if (filtered_pids) {
1979                 tracepoint_synchronize_unregister();
1980                 trace_pid_list_free(filtered_pids);
1981         } else if (pid_list && !other_pids) {
1982                 register_pid_events(tr);
1983         }
1984
1985         /*
1986          * Ignoring of pids is done at task switch. But we have to
1987          * check for those tasks that are currently running.
1988          * Always do this in case a pid was appended or removed.
1989          */
1990         on_each_cpu(ignore_task_cpu, tr, 1);
1991
1992  out:
1993         mutex_unlock(&event_mutex);
1994
1995         if (ret > 0)
1996                 *ppos += ret;
1997
1998         return ret;
1999 }
2000
2001 static ssize_t
2002 ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
2003                        size_t cnt, loff_t *ppos)
2004 {
2005         return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
2006 }
2007
2008 static ssize_t
2009 ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
2010                         size_t cnt, loff_t *ppos)
2011 {
2012         return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
2013 }
2014
2015 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
2016 static int ftrace_event_set_open(struct inode *inode, struct file *file);
2017 static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
2018 static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
2019 static int ftrace_event_release(struct inode *inode, struct file *file);
2020
2021 static const struct seq_operations show_event_seq_ops = {
2022         .start = t_start,
2023         .next = t_next,
2024         .show = t_show,
2025         .stop = t_stop,
2026 };
2027
2028 static const struct seq_operations show_set_event_seq_ops = {
2029         .start = s_start,
2030         .next = s_next,
2031         .show = t_show,
2032         .stop = t_stop,
2033 };
2034
2035 static const struct seq_operations show_set_pid_seq_ops = {
2036         .start = p_start,
2037         .next = p_next,
2038         .show = trace_pid_show,
2039         .stop = p_stop,
2040 };
2041
2042 static const struct seq_operations show_set_no_pid_seq_ops = {
2043         .start = np_start,
2044         .next = np_next,
2045         .show = trace_pid_show,
2046         .stop = p_stop,
2047 };
2048
2049 static const struct file_operations ftrace_avail_fops = {
2050         .open = ftrace_event_avail_open,
2051         .read = seq_read,
2052         .llseek = seq_lseek,
2053         .release = seq_release,
2054 };
2055
2056 static const struct file_operations ftrace_set_event_fops = {
2057         .open = ftrace_event_set_open,
2058         .read = seq_read,
2059         .write = ftrace_event_write,
2060         .llseek = seq_lseek,
2061         .release = ftrace_event_release,
2062 };
2063
2064 static const struct file_operations ftrace_set_event_pid_fops = {
2065         .open = ftrace_event_set_pid_open,
2066         .read = seq_read,
2067         .write = ftrace_event_pid_write,
2068         .llseek = seq_lseek,
2069         .release = ftrace_event_release,
2070 };
2071
2072 static const struct file_operations ftrace_set_event_notrace_pid_fops = {
2073         .open = ftrace_event_set_npid_open,
2074         .read = seq_read,
2075         .write = ftrace_event_npid_write,
2076         .llseek = seq_lseek,
2077         .release = ftrace_event_release,
2078 };
2079
2080 static const struct file_operations ftrace_enable_fops = {
2081         .open = tracing_open_file_tr,
2082         .read = event_enable_read,
2083         .write = event_enable_write,
2084         .release = tracing_release_file_tr,
2085         .llseek = default_llseek,
2086 };
2087
2088 static const struct file_operations ftrace_event_format_fops = {
2089         .open = trace_format_open,
2090         .read = seq_read,
2091         .llseek = seq_lseek,
2092         .release = seq_release,
2093 };
2094
2095 static const struct file_operations ftrace_event_id_fops = {
2096         .read = event_id_read,
2097         .llseek = default_llseek,
2098 };
2099
2100 static const struct file_operations ftrace_event_filter_fops = {
2101         .open = tracing_open_file_tr,
2102         .read = event_filter_read,
2103         .write = event_filter_write,
2104         .release = tracing_release_file_tr,
2105         .llseek = default_llseek,
2106 };
2107
2108 static const struct file_operations ftrace_subsystem_filter_fops = {
2109         .open = subsystem_open,
2110         .read = subsystem_filter_read,
2111         .write = subsystem_filter_write,
2112         .llseek = default_llseek,
2113         .release = subsystem_release,
2114 };
2115
2116 static const struct file_operations ftrace_system_enable_fops = {
2117         .open = subsystem_open,
2118         .read = system_enable_read,
2119         .write = system_enable_write,
2120         .llseek = default_llseek,
2121         .release = subsystem_release,
2122 };
2123
2124 static const struct file_operations ftrace_tr_enable_fops = {
2125         .open = system_tr_open,
2126         .read = system_enable_read,
2127         .write = system_enable_write,
2128         .llseek = default_llseek,
2129         .release = subsystem_release,
2130 };
2131
2132 static const struct file_operations ftrace_show_header_fops = {
2133         .open = tracing_open_generic,
2134         .read = show_header,
2135         .llseek = default_llseek,
2136 };
2137
2138 static int
2139 ftrace_event_open(struct inode *inode, struct file *file,
2140                   const struct seq_operations *seq_ops)
2141 {
2142         struct seq_file *m;
2143         int ret;
2144
2145         ret = security_locked_down(LOCKDOWN_TRACEFS);
2146         if (ret)
2147                 return ret;
2148
2149         ret = seq_open(file, seq_ops);
2150         if (ret < 0)
2151                 return ret;
2152         m = file->private_data;
2153         /* copy tr over to seq ops */
2154         m->private = inode->i_private;
2155
2156         return ret;
2157 }
2158
2159 static int ftrace_event_release(struct inode *inode, struct file *file)
2160 {
2161         struct trace_array *tr = inode->i_private;
2162
2163         trace_array_put(tr);
2164
2165         return seq_release(inode, file);
2166 }
2167
2168 static int
2169 ftrace_event_avail_open(struct inode *inode, struct file *file)
2170 {
2171         const struct seq_operations *seq_ops = &show_event_seq_ops;
2172
2173         /* Checks for tracefs lockdown */
2174         return ftrace_event_open(inode, file, seq_ops);
2175 }
2176
2177 static int
2178 ftrace_event_set_open(struct inode *inode, struct file *file)
2179 {
2180         const struct seq_operations *seq_ops = &show_set_event_seq_ops;
2181         struct trace_array *tr = inode->i_private;
2182         int ret;
2183
2184         ret = tracing_check_open_get_tr(tr);
2185         if (ret)
2186                 return ret;
2187
2188         if ((file->f_mode & FMODE_WRITE) &&
2189             (file->f_flags & O_TRUNC))
2190                 ftrace_clear_events(tr);
2191
2192         ret = ftrace_event_open(inode, file, seq_ops);
2193         if (ret < 0)
2194                 trace_array_put(tr);
2195         return ret;
2196 }
2197
2198 static int
2199 ftrace_event_set_pid_open(struct inode *inode, struct file *file)
2200 {
2201         const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
2202         struct trace_array *tr = inode->i_private;
2203         int ret;
2204
2205         ret = tracing_check_open_get_tr(tr);
2206         if (ret)
2207                 return ret;
2208
2209         if ((file->f_mode & FMODE_WRITE) &&
2210             (file->f_flags & O_TRUNC))
2211                 ftrace_clear_event_pids(tr, TRACE_PIDS);
2212
2213         ret = ftrace_event_open(inode, file, seq_ops);
2214         if (ret < 0)
2215                 trace_array_put(tr);
2216         return ret;
2217 }
2218
2219 static int
2220 ftrace_event_set_npid_open(struct inode *inode, struct file *file)
2221 {
2222         const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops;
2223         struct trace_array *tr = inode->i_private;
2224         int ret;
2225
2226         ret = tracing_check_open_get_tr(tr);
2227         if (ret)
2228                 return ret;
2229
2230         if ((file->f_mode & FMODE_WRITE) &&
2231             (file->f_flags & O_TRUNC))
2232                 ftrace_clear_event_pids(tr, TRACE_NO_PIDS);
2233
2234         ret = ftrace_event_open(inode, file, seq_ops);
2235         if (ret < 0)
2236                 trace_array_put(tr);
2237         return ret;
2238 }
2239
2240 static struct event_subsystem *
2241 create_new_subsystem(const char *name)
2242 {
2243         struct event_subsystem *system;
2244
2245         /* need to create new entry */
2246         system = kmalloc(sizeof(*system), GFP_KERNEL);
2247         if (!system)
2248                 return NULL;
2249
2250         system->ref_count = 1;
2251
2252         /* Only allocate if dynamic (kprobes and modules) */
2253         system->name = kstrdup_const(name, GFP_KERNEL);
2254         if (!system->name)
2255                 goto out_free;
2256
2257         system->filter = NULL;
2258
2259         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
2260         if (!system->filter)
2261                 goto out_free;
2262
2263         list_add(&system->list, &event_subsystems);
2264
2265         return system;
2266
2267  out_free:
2268         kfree_const(system->name);
2269         kfree(system);
2270         return NULL;
2271 }
2272
2273 static struct dentry *
2274 event_subsystem_dir(struct trace_array *tr, const char *name,
2275                     struct trace_event_file *file, struct dentry *parent)
2276 {
2277         struct trace_subsystem_dir *dir;
2278         struct event_subsystem *system;
2279         struct dentry *entry;
2280
2281         /* First see if we did not already create this dir */
2282         list_for_each_entry(dir, &tr->systems, list) {
2283                 system = dir->subsystem;
2284                 if (strcmp(system->name, name) == 0) {
2285                         dir->nr_events++;
2286                         file->system = dir;
2287                         return dir->entry;
2288                 }
2289         }
2290
2291         /* Now see if the system itself exists. */
2292         list_for_each_entry(system, &event_subsystems, list) {
2293                 if (strcmp(system->name, name) == 0)
2294                         break;
2295         }
2296         /* Reset system variable when not found */
2297         if (&system->list == &event_subsystems)
2298                 system = NULL;
2299
2300         dir = kmalloc(sizeof(*dir), GFP_KERNEL);
2301         if (!dir)
2302                 goto out_fail;
2303
2304         if (!system) {
2305                 system = create_new_subsystem(name);
2306                 if (!system)
2307                         goto out_free;
2308         } else
2309                 __get_system(system);
2310
2311         dir->entry = tracefs_create_dir(name, parent);
2312         if (!dir->entry) {
2313                 pr_warn("Failed to create system directory %s\n", name);
2314                 __put_system(system);
2315                 goto out_free;
2316         }
2317
2318         dir->tr = tr;
2319         dir->ref_count = 1;
2320         dir->nr_events = 1;
2321         dir->subsystem = system;
2322         file->system = dir;
2323
2324         /* the ftrace system is special, do not create enable or filter files */
2325         if (strcmp(name, "ftrace") != 0) {
2326
2327                 entry = tracefs_create_file("filter", TRACE_MODE_WRITE,
2328                                             dir->entry, dir,
2329                                             &ftrace_subsystem_filter_fops);
2330                 if (!entry) {
2331                         kfree(system->filter);
2332                         system->filter = NULL;
2333                         pr_warn("Could not create tracefs '%s/filter' entry\n", name);
2334                 }
2335
2336                 trace_create_file("enable", TRACE_MODE_WRITE, dir->entry, dir,
2337                                   &ftrace_system_enable_fops);
2338         }
2339
2340         list_add(&dir->list, &tr->systems);
2341
2342         return dir->entry;
2343
2344  out_free:
2345         kfree(dir);
2346  out_fail:
2347         /* Only print this message if failed on memory allocation */
2348         if (!dir || !system)
2349                 pr_warn("No memory to create event subsystem %s\n", name);
2350         return NULL;
2351 }
2352
2353 static int
2354 event_define_fields(struct trace_event_call *call)
2355 {
2356         struct list_head *head;
2357         int ret = 0;
2358
2359         /*
2360          * Other events may have the same class. Only update
2361          * the fields if they are not already defined.
2362          */
2363         head = trace_get_fields(call);
2364         if (list_empty(head)) {
2365                 struct trace_event_fields *field = call->class->fields_array;
2366                 unsigned int offset = sizeof(struct trace_entry);
2367
2368                 for (; field->type; field++) {
2369                         if (field->type == TRACE_FUNCTION_TYPE) {
2370                                 field->define_fields(call);
2371                                 break;
2372                         }
2373
2374                         offset = ALIGN(offset, field->align);
2375                         ret = trace_define_field(call, field->type, field->name,
2376                                                  offset, field->size,
2377                                                  field->is_signed, field->filter_type);
2378                         if (WARN_ON_ONCE(ret)) {
2379                                 pr_err("error code is %d\n", ret);
2380                                 break;
2381                         }
2382
2383                         offset += field->size;
2384                 }
2385         }
2386
2387         return ret;
2388 }
2389
2390 static int
2391 event_create_dir(struct dentry *parent, struct trace_event_file *file)
2392 {
2393         struct trace_event_call *call = file->event_call;
2394         struct trace_array *tr = file->tr;
2395         struct dentry *d_events;
2396         const char *name;
2397         int ret;
2398
2399         /*
2400          * If the trace point header did not define TRACE_SYSTEM
2401          * then the system would be called "TRACE_SYSTEM".
2402          */
2403         if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
2404                 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
2405                 if (!d_events)
2406                         return -ENOMEM;
2407         } else
2408                 d_events = parent;
2409
2410         name = trace_event_name(call);
2411         file->dir = tracefs_create_dir(name, d_events);
2412         if (!file->dir) {
2413                 pr_warn("Could not create tracefs '%s' directory\n", name);
2414                 return -1;
2415         }
2416
2417         if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
2418                 trace_create_file("enable", TRACE_MODE_WRITE, file->dir, file,
2419                                   &ftrace_enable_fops);
2420
2421 #ifdef CONFIG_PERF_EVENTS
2422         if (call->event.type && call->class->reg)
2423                 trace_create_file("id", TRACE_MODE_READ, file->dir,
2424                                   (void *)(long)call->event.type,
2425                                   &ftrace_event_id_fops);
2426 #endif
2427
2428         ret = event_define_fields(call);
2429         if (ret < 0) {
2430                 pr_warn("Could not initialize trace point events/%s\n", name);
2431                 return ret;
2432         }
2433
2434         /*
2435          * Only event directories that can be enabled should have
2436          * triggers or filters.
2437          */
2438         if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
2439                 trace_create_file("filter", TRACE_MODE_WRITE, file->dir,
2440                                   file, &ftrace_event_filter_fops);
2441
2442                 trace_create_file("trigger", TRACE_MODE_WRITE, file->dir,
2443                                   file, &event_trigger_fops);
2444         }
2445
2446 #ifdef CONFIG_HIST_TRIGGERS
2447         trace_create_file("hist", TRACE_MODE_READ, file->dir, file,
2448                           &event_hist_fops);
2449 #endif
2450 #ifdef CONFIG_HIST_TRIGGERS_DEBUG
2451         trace_create_file("hist_debug", TRACE_MODE_READ, file->dir, file,
2452                           &event_hist_debug_fops);
2453 #endif
2454         trace_create_file("format", TRACE_MODE_READ, file->dir, call,
2455                           &ftrace_event_format_fops);
2456
2457 #ifdef CONFIG_TRACE_EVENT_INJECT
2458         if (call->event.type && call->class->reg)
2459                 trace_create_file("inject", 0200, file->dir, file,
2460                                   &event_inject_fops);
2461 #endif
2462
2463         return 0;
2464 }
2465
2466 static void remove_event_from_tracers(struct trace_event_call *call)
2467 {
2468         struct trace_event_file *file;
2469         struct trace_array *tr;
2470
2471         do_for_each_event_file_safe(tr, file) {
2472                 if (file->event_call != call)
2473                         continue;
2474
2475                 remove_event_file_dir(file);
2476                 /*
2477                  * The do_for_each_event_file_safe() is
2478                  * a double loop. After finding the call for this
2479                  * trace_array, we use break to jump to the next
2480                  * trace_array.
2481                  */
2482                 break;
2483         } while_for_each_event_file();
2484 }
2485
2486 static void event_remove(struct trace_event_call *call)
2487 {
2488         struct trace_array *tr;
2489         struct trace_event_file *file;
2490
2491         do_for_each_event_file(tr, file) {
2492                 if (file->event_call != call)
2493                         continue;
2494
2495                 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2496                         tr->clear_trace = true;
2497
2498                 ftrace_event_enable_disable(file, 0);
2499                 /*
2500                  * The do_for_each_event_file() is
2501                  * a double loop. After finding the call for this
2502                  * trace_array, we use break to jump to the next
2503                  * trace_array.
2504                  */
2505                 break;
2506         } while_for_each_event_file();
2507
2508         if (call->event.funcs)
2509                 __unregister_trace_event(&call->event);
2510         remove_event_from_tracers(call);
2511         list_del(&call->list);
2512 }
2513
2514 static int event_init(struct trace_event_call *call)
2515 {
2516         int ret = 0;
2517         const char *name;
2518
2519         name = trace_event_name(call);
2520         if (WARN_ON(!name))
2521                 return -EINVAL;
2522
2523         if (call->class->raw_init) {
2524                 ret = call->class->raw_init(call);
2525                 if (ret < 0 && ret != -ENOSYS)
2526                         pr_warn("Could not initialize trace events/%s\n", name);
2527         }
2528
2529         return ret;
2530 }
2531
2532 static int
2533 __register_event(struct trace_event_call *call, struct module *mod)
2534 {
2535         int ret;
2536
2537         ret = event_init(call);
2538         if (ret < 0)
2539                 return ret;
2540
2541         list_add(&call->list, &ftrace_events);
2542         if (call->flags & TRACE_EVENT_FL_DYNAMIC)
2543                 atomic_set(&call->refcnt, 0);
2544         else
2545                 call->module = mod;
2546
2547         return 0;
2548 }
2549
2550 static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2551 {
2552         int rlen;
2553         int elen;
2554
2555         /* Find the length of the eval value as a string */
2556         elen = snprintf(ptr, 0, "%ld", map->eval_value);
2557         /* Make sure there's enough room to replace the string with the value */
2558         if (len < elen)
2559                 return NULL;
2560
2561         snprintf(ptr, elen + 1, "%ld", map->eval_value);
2562
2563         /* Get the rest of the string of ptr */
2564         rlen = strlen(ptr + len);
2565         memmove(ptr + elen, ptr + len, rlen);
2566         /* Make sure we end the new string */
2567         ptr[elen + rlen] = 0;
2568
2569         return ptr + elen;
2570 }
2571
2572 static void update_event_printk(struct trace_event_call *call,
2573                                 struct trace_eval_map *map)
2574 {
2575         char *ptr;
2576         int quote = 0;
2577         int len = strlen(map->eval_string);
2578
2579         for (ptr = call->print_fmt; *ptr; ptr++) {
2580                 if (*ptr == '\\') {
2581                         ptr++;
2582                         /* paranoid */
2583                         if (!*ptr)
2584                                 break;
2585                         continue;
2586                 }
2587                 if (*ptr == '"') {
2588                         quote ^= 1;
2589                         continue;
2590                 }
2591                 if (quote)
2592                         continue;
2593                 if (isdigit(*ptr)) {
2594                         /* skip numbers */
2595                         do {
2596                                 ptr++;
2597                                 /* Check for alpha chars like ULL */
2598                         } while (isalnum(*ptr));
2599                         if (!*ptr)
2600                                 break;
2601                         /*
2602                          * A number must have some kind of delimiter after
2603                          * it, and we can ignore that too.
2604                          */
2605                         continue;
2606                 }
2607                 if (isalpha(*ptr) || *ptr == '_') {
2608                         if (strncmp(map->eval_string, ptr, len) == 0 &&
2609                             !isalnum(ptr[len]) && ptr[len] != '_') {
2610                                 ptr = eval_replace(ptr, map, len);
2611                                 /* enum/sizeof string smaller than value */
2612                                 if (WARN_ON_ONCE(!ptr))
2613                                         return;
2614                                 /*
2615                                  * No need to decrement here, as eval_replace()
2616                                  * returns the pointer to the character passed
2617                                  * the eval, and two evals can not be placed
2618                                  * back to back without something in between.
2619                                  * We can skip that something in between.
2620                                  */
2621                                 continue;
2622                         }
2623                 skip_more:
2624                         do {
2625                                 ptr++;
2626                         } while (isalnum(*ptr) || *ptr == '_');
2627                         if (!*ptr)
2628                                 break;
2629                         /*
2630                          * If what comes after this variable is a '.' or
2631                          * '->' then we can continue to ignore that string.
2632                          */
2633                         if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2634                                 ptr += *ptr == '.' ? 1 : 2;
2635                                 if (!*ptr)
2636                                         break;
2637                                 goto skip_more;
2638                         }
2639                         /*
2640                          * Once again, we can skip the delimiter that came
2641                          * after the string.
2642                          */
2643                         continue;
2644                 }
2645         }
2646 }
2647
2648 static void add_str_to_module(struct module *module, char *str)
2649 {
2650         struct module_string *modstr;
2651
2652         modstr = kmalloc(sizeof(*modstr), GFP_KERNEL);
2653
2654         /*
2655          * If we failed to allocate memory here, then we'll just
2656          * let the str memory leak when the module is removed.
2657          * If this fails to allocate, there's worse problems than
2658          * a leaked string on module removal.
2659          */
2660         if (WARN_ON_ONCE(!modstr))
2661                 return;
2662
2663         modstr->module = module;
2664         modstr->str = str;
2665
2666         list_add(&modstr->next, &module_strings);
2667 }
2668
2669 static void update_event_fields(struct trace_event_call *call,
2670                                 struct trace_eval_map *map)
2671 {
2672         struct ftrace_event_field *field;
2673         struct list_head *head;
2674         char *ptr;
2675         char *str;
2676         int len = strlen(map->eval_string);
2677
2678         /* Dynamic events should never have field maps */
2679         if (WARN_ON_ONCE(call->flags & TRACE_EVENT_FL_DYNAMIC))
2680                 return;
2681
2682         head = trace_get_fields(call);
2683         list_for_each_entry(field, head, link) {
2684                 ptr = strchr(field->type, '[');
2685                 if (!ptr)
2686                         continue;
2687                 ptr++;
2688
2689                 if (!isalpha(*ptr) && *ptr != '_')
2690                         continue;
2691
2692                 if (strncmp(map->eval_string, ptr, len) != 0)
2693                         continue;
2694
2695                 str = kstrdup(field->type, GFP_KERNEL);
2696                 if (WARN_ON_ONCE(!str))
2697                         return;
2698                 ptr = str + (ptr - field->type);
2699                 ptr = eval_replace(ptr, map, len);
2700                 /* enum/sizeof string smaller than value */
2701                 if (WARN_ON_ONCE(!ptr)) {
2702                         kfree(str);
2703                         continue;
2704                 }
2705
2706                 /*
2707                  * If the event is part of a module, then we need to free the string
2708                  * when the module is removed. Otherwise, it will stay allocated
2709                  * until a reboot.
2710                  */
2711                 if (call->module)
2712                         add_str_to_module(call->module, str);
2713
2714                 field->type = str;
2715         }
2716 }
2717
2718 void trace_event_eval_update(struct trace_eval_map **map, int len)
2719 {
2720         struct trace_event_call *call, *p;
2721         const char *last_system = NULL;
2722         bool first = false;
2723         int last_i;
2724         int i;
2725
2726         down_write(&trace_event_sem);
2727         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2728                 /* events are usually grouped together with systems */
2729                 if (!last_system || call->class->system != last_system) {
2730                         first = true;
2731                         last_i = 0;
2732                         last_system = call->class->system;
2733                 }
2734
2735                 /*
2736                  * Since calls are grouped by systems, the likelihood that the
2737                  * next call in the iteration belongs to the same system as the
2738                  * previous call is high. As an optimization, we skip searching
2739                  * for a map[] that matches the call's system if the last call
2740                  * was from the same system. That's what last_i is for. If the
2741                  * call has the same system as the previous call, then last_i
2742                  * will be the index of the first map[] that has a matching
2743                  * system.
2744                  */
2745                 for (i = last_i; i < len; i++) {
2746                         if (call->class->system == map[i]->system) {
2747                                 /* Save the first system if need be */
2748                                 if (first) {
2749                                         last_i = i;
2750                                         first = false;
2751                                 }
2752                                 update_event_printk(call, map[i]);
2753                                 update_event_fields(call, map[i]);
2754                         }
2755                 }
2756                 cond_resched();
2757         }
2758         up_write(&trace_event_sem);
2759 }
2760
2761 static struct trace_event_file *
2762 trace_create_new_event(struct trace_event_call *call,
2763                        struct trace_array *tr)
2764 {
2765         struct trace_pid_list *no_pid_list;
2766         struct trace_pid_list *pid_list;
2767         struct trace_event_file *file;
2768
2769         file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2770         if (!file)
2771                 return NULL;
2772
2773         pid_list = rcu_dereference_protected(tr->filtered_pids,
2774                                              lockdep_is_held(&event_mutex));
2775         no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
2776                                              lockdep_is_held(&event_mutex));
2777
2778         if (pid_list || no_pid_list)
2779                 file->flags |= EVENT_FILE_FL_PID_FILTER;
2780
2781         file->event_call = call;
2782         file->tr = tr;
2783         atomic_set(&file->sm_ref, 0);
2784         atomic_set(&file->tm_ref, 0);
2785         INIT_LIST_HEAD(&file->triggers);
2786         list_add(&file->list, &tr->events);
2787
2788         return file;
2789 }
2790
2791 /* Add an event to a trace directory */
2792 static int
2793 __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2794 {
2795         struct trace_event_file *file;
2796
2797         file = trace_create_new_event(call, tr);
2798         if (!file)
2799                 return -ENOMEM;
2800
2801         if (eventdir_initialized)
2802                 return event_create_dir(tr->event_dir, file);
2803         else
2804                 return event_define_fields(call);
2805 }
2806
2807 /*
2808  * Just create a descriptor for early init. A descriptor is required
2809  * for enabling events at boot. We want to enable events before
2810  * the filesystem is initialized.
2811  */
2812 static int
2813 __trace_early_add_new_event(struct trace_event_call *call,
2814                             struct trace_array *tr)
2815 {
2816         struct trace_event_file *file;
2817
2818         file = trace_create_new_event(call, tr);
2819         if (!file)
2820                 return -ENOMEM;
2821
2822         return event_define_fields(call);
2823 }
2824
2825 struct ftrace_module_file_ops;
2826 static void __add_event_to_tracers(struct trace_event_call *call);
2827
2828 /* Add an additional event_call dynamically */
2829 int trace_add_event_call(struct trace_event_call *call)
2830 {
2831         int ret;
2832         lockdep_assert_held(&event_mutex);
2833
2834         mutex_lock(&trace_types_lock);
2835
2836         ret = __register_event(call, NULL);
2837         if (ret >= 0)
2838                 __add_event_to_tracers(call);
2839
2840         mutex_unlock(&trace_types_lock);
2841         return ret;
2842 }
2843
2844 /*
2845  * Must be called under locking of trace_types_lock, event_mutex and
2846  * trace_event_sem.
2847  */
2848 static void __trace_remove_event_call(struct trace_event_call *call)
2849 {
2850         event_remove(call);
2851         trace_destroy_fields(call);
2852         free_event_filter(call->filter);
2853         call->filter = NULL;
2854 }
2855
2856 static int probe_remove_event_call(struct trace_event_call *call)
2857 {
2858         struct trace_array *tr;
2859         struct trace_event_file *file;
2860
2861 #ifdef CONFIG_PERF_EVENTS
2862         if (call->perf_refcount)
2863                 return -EBUSY;
2864 #endif
2865         do_for_each_event_file(tr, file) {
2866                 if (file->event_call != call)
2867                         continue;
2868                 /*
2869                  * We can't rely on ftrace_event_enable_disable(enable => 0)
2870                  * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
2871                  * TRACE_REG_UNREGISTER.
2872                  */
2873                 if (file->flags & EVENT_FILE_FL_ENABLED)
2874                         goto busy;
2875
2876                 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2877                         tr->clear_trace = true;
2878                 /*
2879                  * The do_for_each_event_file_safe() is
2880                  * a double loop. After finding the call for this
2881                  * trace_array, we use break to jump to the next
2882                  * trace_array.
2883                  */
2884                 break;
2885         } while_for_each_event_file();
2886
2887         __trace_remove_event_call(call);
2888
2889         return 0;
2890  busy:
2891         /* No need to clear the trace now */
2892         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2893                 tr->clear_trace = false;
2894         }
2895         return -EBUSY;
2896 }
2897
2898 /* Remove an event_call */
2899 int trace_remove_event_call(struct trace_event_call *call)
2900 {
2901         int ret;
2902
2903         lockdep_assert_held(&event_mutex);
2904
2905         mutex_lock(&trace_types_lock);
2906         down_write(&trace_event_sem);
2907         ret = probe_remove_event_call(call);
2908         up_write(&trace_event_sem);
2909         mutex_unlock(&trace_types_lock);
2910
2911         return ret;
2912 }
2913
2914 #define for_each_event(event, start, end)                       \
2915         for (event = start;                                     \
2916              (unsigned long)event < (unsigned long)end;         \
2917              event++)
2918
2919 #ifdef CONFIG_MODULES
2920
2921 static void trace_module_add_events(struct module *mod)
2922 {
2923         struct trace_event_call **call, **start, **end;
2924
2925         if (!mod->num_trace_events)
2926                 return;
2927
2928         /* Don't add infrastructure for mods without tracepoints */
2929         if (trace_module_has_bad_taint(mod)) {
2930                 pr_err("%s: module has bad taint, not creating trace events\n",
2931                        mod->name);
2932                 return;
2933         }
2934
2935         start = mod->trace_events;
2936         end = mod->trace_events + mod->num_trace_events;
2937
2938         for_each_event(call, start, end) {
2939                 __register_event(*call, mod);
2940                 __add_event_to_tracers(*call);
2941         }
2942 }
2943
2944 static void trace_module_remove_events(struct module *mod)
2945 {
2946         struct trace_event_call *call, *p;
2947         struct module_string *modstr, *m;
2948
2949         down_write(&trace_event_sem);
2950         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2951                 if ((call->flags & TRACE_EVENT_FL_DYNAMIC) || !call->module)
2952                         continue;
2953                 if (call->module == mod)
2954                         __trace_remove_event_call(call);
2955         }
2956         /* Check for any strings allocade for this module */
2957         list_for_each_entry_safe(modstr, m, &module_strings, next) {
2958                 if (modstr->module != mod)
2959                         continue;
2960                 list_del(&modstr->next);
2961                 kfree(modstr->str);
2962                 kfree(modstr);
2963         }
2964         up_write(&trace_event_sem);
2965
2966         /*
2967          * It is safest to reset the ring buffer if the module being unloaded
2968          * registered any events that were used. The only worry is if
2969          * a new module gets loaded, and takes on the same id as the events
2970          * of this module. When printing out the buffer, traced events left
2971          * over from this module may be passed to the new module events and
2972          * unexpected results may occur.
2973          */
2974         tracing_reset_all_online_cpus_unlocked();
2975 }
2976
2977 static int trace_module_notify(struct notifier_block *self,
2978                                unsigned long val, void *data)
2979 {
2980         struct module *mod = data;
2981
2982         mutex_lock(&event_mutex);
2983         mutex_lock(&trace_types_lock);
2984         switch (val) {
2985         case MODULE_STATE_COMING:
2986                 trace_module_add_events(mod);
2987                 break;
2988         case MODULE_STATE_GOING:
2989                 trace_module_remove_events(mod);
2990                 break;
2991         }
2992         mutex_unlock(&trace_types_lock);
2993         mutex_unlock(&event_mutex);
2994
2995         return NOTIFY_OK;
2996 }
2997
2998 static struct notifier_block trace_module_nb = {
2999         .notifier_call = trace_module_notify,
3000         .priority = 1, /* higher than trace.c module notify */
3001 };
3002 #endif /* CONFIG_MODULES */
3003
3004 /* Create a new event directory structure for a trace directory. */
3005 static void
3006 __trace_add_event_dirs(struct trace_array *tr)
3007 {
3008         struct trace_event_call *call;
3009         int ret;
3010
3011         list_for_each_entry(call, &ftrace_events, list) {
3012                 ret = __trace_add_new_event(call, tr);
3013                 if (ret < 0)
3014                         pr_warn("Could not create directory for event %s\n",
3015                                 trace_event_name(call));
3016         }
3017 }
3018
3019 /* Returns any file that matches the system and event */
3020 struct trace_event_file *
3021 __find_event_file(struct trace_array *tr, const char *system, const char *event)
3022 {
3023         struct trace_event_file *file;
3024         struct trace_event_call *call;
3025         const char *name;
3026
3027         list_for_each_entry(file, &tr->events, list) {
3028
3029                 call = file->event_call;
3030                 name = trace_event_name(call);
3031
3032                 if (!name || !call->class)
3033                         continue;
3034
3035                 if (strcmp(event, name) == 0 &&
3036                     strcmp(system, call->class->system) == 0)
3037                         return file;
3038         }
3039         return NULL;
3040 }
3041
3042 /* Returns valid trace event files that match system and event */
3043 struct trace_event_file *
3044 find_event_file(struct trace_array *tr, const char *system, const char *event)
3045 {
3046         struct trace_event_file *file;
3047
3048         file = __find_event_file(tr, system, event);
3049         if (!file || !file->event_call->class->reg ||
3050             file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
3051                 return NULL;
3052
3053         return file;
3054 }
3055
3056 /**
3057  * trace_get_event_file - Find and return a trace event file
3058  * @instance: The name of the trace instance containing the event
3059  * @system: The name of the system containing the event
3060  * @event: The name of the event
3061  *
3062  * Return a trace event file given the trace instance name, trace
3063  * system, and trace event name.  If the instance name is NULL, it
3064  * refers to the top-level trace array.
3065  *
3066  * This function will look it up and return it if found, after calling
3067  * trace_array_get() to prevent the instance from going away, and
3068  * increment the event's module refcount to prevent it from being
3069  * removed.
3070  *
3071  * To release the file, call trace_put_event_file(), which will call
3072  * trace_array_put() and decrement the event's module refcount.
3073  *
3074  * Return: The trace event on success, ERR_PTR otherwise.
3075  */
3076 struct trace_event_file *trace_get_event_file(const char *instance,
3077                                               const char *system,
3078                                               const char *event)
3079 {
3080         struct trace_array *tr = top_trace_array();
3081         struct trace_event_file *file = NULL;
3082         int ret = -EINVAL;
3083
3084         if (instance) {
3085                 tr = trace_array_find_get(instance);
3086                 if (!tr)
3087                         return ERR_PTR(-ENOENT);
3088         } else {
3089                 ret = trace_array_get(tr);
3090                 if (ret)
3091                         return ERR_PTR(ret);
3092         }
3093
3094         mutex_lock(&event_mutex);
3095
3096         file = find_event_file(tr, system, event);
3097         if (!file) {
3098                 trace_array_put(tr);
3099                 ret = -EINVAL;
3100                 goto out;
3101         }
3102
3103         /* Don't let event modules unload while in use */
3104         ret = trace_event_try_get_ref(file->event_call);
3105         if (!ret) {
3106                 trace_array_put(tr);
3107                 ret = -EBUSY;
3108                 goto out;
3109         }
3110
3111         ret = 0;
3112  out:
3113         mutex_unlock(&event_mutex);
3114
3115         if (ret)
3116                 file = ERR_PTR(ret);
3117
3118         return file;
3119 }
3120 EXPORT_SYMBOL_GPL(trace_get_event_file);
3121
3122 /**
3123  * trace_put_event_file - Release a file from trace_get_event_file()
3124  * @file: The trace event file
3125  *
3126  * If a file was retrieved using trace_get_event_file(), this should
3127  * be called when it's no longer needed.  It will cancel the previous
3128  * trace_array_get() called by that function, and decrement the
3129  * event's module refcount.
3130  */
3131 void trace_put_event_file(struct trace_event_file *file)
3132 {
3133         mutex_lock(&event_mutex);
3134         trace_event_put_ref(file->event_call);
3135         mutex_unlock(&event_mutex);
3136
3137         trace_array_put(file->tr);
3138 }
3139 EXPORT_SYMBOL_GPL(trace_put_event_file);
3140
3141 #ifdef CONFIG_DYNAMIC_FTRACE
3142
3143 /* Avoid typos */
3144 #define ENABLE_EVENT_STR        "enable_event"
3145 #define DISABLE_EVENT_STR       "disable_event"
3146
3147 struct event_probe_data {
3148         struct trace_event_file *file;
3149         unsigned long                   count;
3150         int                             ref;
3151         bool                            enable;
3152 };
3153
3154 static void update_event_probe(struct event_probe_data *data)
3155 {
3156         if (data->enable)
3157                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3158         else
3159                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3160 }
3161
3162 static void
3163 event_enable_probe(unsigned long ip, unsigned long parent_ip,
3164                    struct trace_array *tr, struct ftrace_probe_ops *ops,
3165                    void *data)
3166 {
3167         struct ftrace_func_mapper *mapper = data;
3168         struct event_probe_data *edata;
3169         void **pdata;
3170
3171         pdata = ftrace_func_mapper_find_ip(mapper, ip);
3172         if (!pdata || !*pdata)
3173                 return;
3174
3175         edata = *pdata;
3176         update_event_probe(edata);
3177 }
3178
3179 static void
3180 event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
3181                          struct trace_array *tr, struct ftrace_probe_ops *ops,
3182                          void *data)
3183 {
3184         struct ftrace_func_mapper *mapper = data;
3185         struct event_probe_data *edata;
3186         void **pdata;
3187
3188         pdata = ftrace_func_mapper_find_ip(mapper, ip);
3189         if (!pdata || !*pdata)
3190                 return;
3191
3192         edata = *pdata;
3193
3194         if (!edata->count)
3195                 return;
3196
3197         /* Skip if the event is in a state we want to switch to */
3198         if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
3199                 return;
3200
3201         if (edata->count != -1)
3202                 (edata->count)--;
3203
3204         update_event_probe(edata);
3205 }
3206
3207 static int
3208 event_enable_print(struct seq_file *m, unsigned long ip,
3209                    struct ftrace_probe_ops *ops, void *data)
3210 {
3211         struct ftrace_func_mapper *mapper = data;
3212         struct event_probe_data *edata;
3213         void **pdata;
3214
3215         pdata = ftrace_func_mapper_find_ip(mapper, ip);
3216
3217         if (WARN_ON_ONCE(!pdata || !*pdata))
3218                 return 0;
3219
3220         edata = *pdata;
3221
3222         seq_printf(m, "%ps:", (void *)ip);
3223
3224         seq_printf(m, "%s:%s:%s",
3225                    edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
3226                    edata->file->event_call->class->system,
3227                    trace_event_name(edata->file->event_call));
3228
3229         if (edata->count == -1)
3230                 seq_puts(m, ":unlimited\n");
3231         else
3232                 seq_printf(m, ":count=%ld\n", edata->count);
3233
3234         return 0;
3235 }
3236
3237 static int
3238 event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
3239                   unsigned long ip, void *init_data, void **data)
3240 {
3241         struct ftrace_func_mapper *mapper = *data;
3242         struct event_probe_data *edata = init_data;
3243         int ret;
3244
3245         if (!mapper) {
3246                 mapper = allocate_ftrace_func_mapper();
3247                 if (!mapper)
3248                         return -ENODEV;
3249                 *data = mapper;
3250         }
3251
3252         ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
3253         if (ret < 0)
3254                 return ret;
3255
3256         edata->ref++;
3257
3258         return 0;
3259 }
3260
3261 static int free_probe_data(void *data)
3262 {
3263         struct event_probe_data *edata = data;
3264
3265         edata->ref--;
3266         if (!edata->ref) {
3267                 /* Remove the SOFT_MODE flag */
3268                 __ftrace_event_enable_disable(edata->file, 0, 1);
3269                 trace_event_put_ref(edata->file->event_call);
3270                 kfree(edata);
3271         }
3272         return 0;
3273 }
3274
3275 static void
3276 event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
3277                   unsigned long ip, void *data)
3278 {
3279         struct ftrace_func_mapper *mapper = data;
3280         struct event_probe_data *edata;
3281
3282         if (!ip) {
3283                 if (!mapper)
3284                         return;
3285                 free_ftrace_func_mapper(mapper, free_probe_data);
3286                 return;
3287         }
3288
3289         edata = ftrace_func_mapper_remove_ip(mapper, ip);
3290
3291         if (WARN_ON_ONCE(!edata))
3292                 return;
3293
3294         if (WARN_ON_ONCE(edata->ref <= 0))
3295                 return;
3296
3297         free_probe_data(edata);
3298 }
3299
3300 static struct ftrace_probe_ops event_enable_probe_ops = {
3301         .func                   = event_enable_probe,
3302         .print                  = event_enable_print,
3303         .init                   = event_enable_init,
3304         .free                   = event_enable_free,
3305 };
3306
3307 static struct ftrace_probe_ops event_enable_count_probe_ops = {
3308         .func                   = event_enable_count_probe,
3309         .print                  = event_enable_print,
3310         .init                   = event_enable_init,
3311         .free                   = event_enable_free,
3312 };
3313
3314 static struct ftrace_probe_ops event_disable_probe_ops = {
3315         .func                   = event_enable_probe,
3316         .print                  = event_enable_print,
3317         .init                   = event_enable_init,
3318         .free                   = event_enable_free,
3319 };
3320
3321 static struct ftrace_probe_ops event_disable_count_probe_ops = {
3322         .func                   = event_enable_count_probe,
3323         .print                  = event_enable_print,
3324         .init                   = event_enable_init,
3325         .free                   = event_enable_free,
3326 };
3327
3328 static int
3329 event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
3330                   char *glob, char *cmd, char *param, int enabled)
3331 {
3332         struct trace_event_file *file;
3333         struct ftrace_probe_ops *ops;
3334         struct event_probe_data *data;
3335         const char *system;
3336         const char *event;
3337         char *number;
3338         bool enable;
3339         int ret;
3340
3341         if (!tr)
3342                 return -ENODEV;
3343
3344         /* hash funcs only work with set_ftrace_filter */
3345         if (!enabled || !param)
3346                 return -EINVAL;
3347
3348         system = strsep(&param, ":");
3349         if (!param)
3350                 return -EINVAL;
3351
3352         event = strsep(&param, ":");
3353
3354         mutex_lock(&event_mutex);
3355
3356         ret = -EINVAL;
3357         file = find_event_file(tr, system, event);
3358         if (!file)
3359                 goto out;
3360
3361         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
3362
3363         if (enable)
3364                 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
3365         else
3366                 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
3367
3368         if (glob[0] == '!') {
3369                 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
3370                 goto out;
3371         }
3372
3373         ret = -ENOMEM;
3374
3375         data = kzalloc(sizeof(*data), GFP_KERNEL);
3376         if (!data)
3377                 goto out;
3378
3379         data->enable = enable;
3380         data->count = -1;
3381         data->file = file;
3382
3383         if (!param)
3384                 goto out_reg;
3385
3386         number = strsep(&param, ":");
3387
3388         ret = -EINVAL;
3389         if (!strlen(number))
3390                 goto out_free;
3391
3392         /*
3393          * We use the callback data field (which is a pointer)
3394          * as our counter.
3395          */
3396         ret = kstrtoul(number, 0, &data->count);
3397         if (ret)
3398                 goto out_free;
3399
3400  out_reg:
3401         /* Don't let event modules unload while probe registered */
3402         ret = trace_event_try_get_ref(file->event_call);
3403         if (!ret) {
3404                 ret = -EBUSY;
3405                 goto out_free;
3406         }
3407
3408         ret = __ftrace_event_enable_disable(file, 1, 1);
3409         if (ret < 0)
3410                 goto out_put;
3411
3412         ret = register_ftrace_function_probe(glob, tr, ops, data);
3413         /*
3414          * The above returns on success the # of functions enabled,
3415          * but if it didn't find any functions it returns zero.
3416          * Consider no functions a failure too.
3417          */
3418         if (!ret) {
3419                 ret = -ENOENT;
3420                 goto out_disable;
3421         } else if (ret < 0)
3422                 goto out_disable;
3423         /* Just return zero, not the number of enabled functions */
3424         ret = 0;
3425  out:
3426         mutex_unlock(&event_mutex);
3427         return ret;
3428
3429  out_disable:
3430         __ftrace_event_enable_disable(file, 0, 1);
3431  out_put:
3432         trace_event_put_ref(file->event_call);
3433  out_free:
3434         kfree(data);
3435         goto out;
3436 }
3437
3438 static struct ftrace_func_command event_enable_cmd = {
3439         .name                   = ENABLE_EVENT_STR,
3440         .func                   = event_enable_func,
3441 };
3442
3443 static struct ftrace_func_command event_disable_cmd = {
3444         .name                   = DISABLE_EVENT_STR,
3445         .func                   = event_enable_func,
3446 };
3447
3448 static __init int register_event_cmds(void)
3449 {
3450         int ret;
3451
3452         ret = register_ftrace_command(&event_enable_cmd);
3453         if (WARN_ON(ret < 0))
3454                 return ret;
3455         ret = register_ftrace_command(&event_disable_cmd);
3456         if (WARN_ON(ret < 0))
3457                 unregister_ftrace_command(&event_enable_cmd);
3458         return ret;
3459 }
3460 #else
3461 static inline int register_event_cmds(void) { return 0; }
3462 #endif /* CONFIG_DYNAMIC_FTRACE */
3463
3464 /*
3465  * The top level array and trace arrays created by boot-time tracing
3466  * have already had its trace_event_file descriptors created in order
3467  * to allow for early events to be recorded.
3468  * This function is called after the tracefs has been initialized,
3469  * and we now have to create the files associated to the events.
3470  */
3471 static void __trace_early_add_event_dirs(struct trace_array *tr)
3472 {
3473         struct trace_event_file *file;
3474         int ret;
3475
3476
3477         list_for_each_entry(file, &tr->events, list) {
3478                 ret = event_create_dir(tr->event_dir, file);
3479                 if (ret < 0)
3480                         pr_warn("Could not create directory for event %s\n",
3481                                 trace_event_name(file->event_call));
3482         }
3483 }
3484
3485 /*
3486  * For early boot up, the top trace array and the trace arrays created
3487  * by boot-time tracing require to have a list of events that can be
3488  * enabled. This must be done before the filesystem is set up in order
3489  * to allow events to be traced early.
3490  */
3491 void __trace_early_add_events(struct trace_array *tr)
3492 {
3493         struct trace_event_call *call;
3494         int ret;
3495
3496         list_for_each_entry(call, &ftrace_events, list) {
3497                 /* Early boot up should not have any modules loaded */
3498                 if (!(call->flags & TRACE_EVENT_FL_DYNAMIC) &&
3499                     WARN_ON_ONCE(call->module))
3500                         continue;
3501
3502                 ret = __trace_early_add_new_event(call, tr);
3503                 if (ret < 0)
3504                         pr_warn("Could not create early event %s\n",
3505                                 trace_event_name(call));
3506         }
3507 }
3508
3509 /* Remove the event directory structure for a trace directory. */
3510 static void
3511 __trace_remove_event_dirs(struct trace_array *tr)
3512 {
3513         struct trace_event_file *file, *next;
3514
3515         list_for_each_entry_safe(file, next, &tr->events, list)
3516                 remove_event_file_dir(file);
3517 }
3518
3519 static void __add_event_to_tracers(struct trace_event_call *call)
3520 {
3521         struct trace_array *tr;
3522
3523         list_for_each_entry(tr, &ftrace_trace_arrays, list)
3524                 __trace_add_new_event(call, tr);
3525 }
3526
3527 extern struct trace_event_call *__start_ftrace_events[];
3528 extern struct trace_event_call *__stop_ftrace_events[];
3529
3530 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
3531
3532 static __init int setup_trace_event(char *str)
3533 {
3534         strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
3535         ring_buffer_expanded = true;
3536         disable_tracing_selftest("running event tracing");
3537
3538         return 1;
3539 }
3540 __setup("trace_event=", setup_trace_event);
3541
3542 /* Expects to have event_mutex held when called */
3543 static int
3544 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
3545 {
3546         struct dentry *d_events;
3547         struct dentry *entry;
3548
3549         entry = tracefs_create_file("set_event", TRACE_MODE_WRITE, parent,
3550                                     tr, &ftrace_set_event_fops);
3551         if (!entry) {
3552                 pr_warn("Could not create tracefs 'set_event' entry\n");
3553                 return -ENOMEM;
3554         }
3555
3556         d_events = tracefs_create_dir("events", parent);
3557         if (!d_events) {
3558                 pr_warn("Could not create tracefs 'events' directory\n");
3559                 return -ENOMEM;
3560         }
3561
3562         entry = trace_create_file("enable", TRACE_MODE_WRITE, d_events,
3563                                   tr, &ftrace_tr_enable_fops);
3564         if (!entry) {
3565                 pr_warn("Could not create tracefs 'enable' entry\n");
3566                 return -ENOMEM;
3567         }
3568
3569         /* There are not as crucial, just warn if they are not created */
3570
3571         entry = tracefs_create_file("set_event_pid", TRACE_MODE_WRITE, parent,
3572                                     tr, &ftrace_set_event_pid_fops);
3573         if (!entry)
3574                 pr_warn("Could not create tracefs 'set_event_pid' entry\n");
3575
3576         entry = tracefs_create_file("set_event_notrace_pid",
3577                                     TRACE_MODE_WRITE, parent, tr,
3578                                     &ftrace_set_event_notrace_pid_fops);
3579         if (!entry)
3580                 pr_warn("Could not create tracefs 'set_event_notrace_pid' entry\n");
3581
3582         /* ring buffer internal formats */
3583         entry = trace_create_file("header_page", TRACE_MODE_READ, d_events,
3584                                   ring_buffer_print_page_header,
3585                                   &ftrace_show_header_fops);
3586         if (!entry)
3587                 pr_warn("Could not create tracefs 'header_page' entry\n");
3588
3589         entry = trace_create_file("header_event", TRACE_MODE_READ, d_events,
3590                                   ring_buffer_print_entry_header,
3591                                   &ftrace_show_header_fops);
3592         if (!entry)
3593                 pr_warn("Could not create tracefs 'header_event' entry\n");
3594
3595         tr->event_dir = d_events;
3596
3597         return 0;
3598 }
3599
3600 /**
3601  * event_trace_add_tracer - add a instance of a trace_array to events
3602  * @parent: The parent dentry to place the files/directories for events in
3603  * @tr: The trace array associated with these events
3604  *
3605  * When a new instance is created, it needs to set up its events
3606  * directory, as well as other files associated with events. It also
3607  * creates the event hierarchy in the @parent/events directory.
3608  *
3609  * Returns 0 on success.
3610  *
3611  * Must be called with event_mutex held.
3612  */
3613 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
3614 {
3615         int ret;
3616
3617         lockdep_assert_held(&event_mutex);
3618
3619         ret = create_event_toplevel_files(parent, tr);
3620         if (ret)
3621                 goto out;
3622
3623         down_write(&trace_event_sem);
3624         /* If tr already has the event list, it is initialized in early boot. */
3625         if (unlikely(!list_empty(&tr->events)))
3626                 __trace_early_add_event_dirs(tr);
3627         else
3628                 __trace_add_event_dirs(tr);
3629         up_write(&trace_event_sem);
3630
3631  out:
3632         return ret;
3633 }
3634
3635 /*
3636  * The top trace array already had its file descriptors created.
3637  * Now the files themselves need to be created.
3638  */
3639 static __init int
3640 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
3641 {
3642         int ret;
3643
3644         mutex_lock(&event_mutex);
3645
3646         ret = create_event_toplevel_files(parent, tr);
3647         if (ret)
3648                 goto out_unlock;
3649
3650         down_write(&trace_event_sem);
3651         __trace_early_add_event_dirs(tr);
3652         up_write(&trace_event_sem);
3653
3654  out_unlock:
3655         mutex_unlock(&event_mutex);
3656
3657         return ret;
3658 }
3659
3660 /* Must be called with event_mutex held */
3661 int event_trace_del_tracer(struct trace_array *tr)
3662 {
3663         lockdep_assert_held(&event_mutex);
3664
3665         /* Disable any event triggers and associated soft-disabled events */
3666         clear_event_triggers(tr);
3667
3668         /* Clear the pid list */
3669         __ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
3670
3671         /* Disable any running events */
3672         __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3673
3674         /* Make sure no more events are being executed */
3675         tracepoint_synchronize_unregister();
3676
3677         down_write(&trace_event_sem);
3678         __trace_remove_event_dirs(tr);
3679         tracefs_remove(tr->event_dir);
3680         up_write(&trace_event_sem);
3681
3682         tr->event_dir = NULL;
3683
3684         return 0;
3685 }
3686
3687 static __init int event_trace_memsetup(void)
3688 {
3689         field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3690         file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3691         return 0;
3692 }
3693
3694 static __init void
3695 early_enable_events(struct trace_array *tr, bool disable_first)
3696 {
3697         char *buf = bootup_event_buf;
3698         char *token;
3699         int ret;
3700
3701         while (true) {
3702                 token = strsep(&buf, ",");
3703
3704                 if (!token)
3705                         break;
3706
3707                 if (*token) {
3708                         /* Restarting syscalls requires that we stop them first */
3709                         if (disable_first)
3710                                 ftrace_set_clr_event(tr, token, 0);
3711
3712                         ret = ftrace_set_clr_event(tr, token, 1);
3713                         if (ret)
3714                                 pr_warn("Failed to enable trace event: %s\n", token);
3715                 }
3716
3717                 /* Put back the comma to allow this to be called again */
3718                 if (buf)
3719                         *(buf - 1) = ',';
3720         }
3721 }
3722
3723 static __init int event_trace_enable(void)
3724 {
3725         struct trace_array *tr = top_trace_array();
3726         struct trace_event_call **iter, *call;
3727         int ret;
3728
3729         if (!tr)
3730                 return -ENODEV;
3731
3732         for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3733
3734                 call = *iter;
3735                 ret = event_init(call);
3736                 if (!ret)
3737                         list_add(&call->list, &ftrace_events);
3738         }
3739
3740         /*
3741          * We need the top trace array to have a working set of trace
3742          * points at early init, before the debug files and directories
3743          * are created. Create the file entries now, and attach them
3744          * to the actual file dentries later.
3745          */
3746         __trace_early_add_events(tr);
3747
3748         early_enable_events(tr, false);
3749
3750         trace_printk_start_comm();
3751
3752         register_event_cmds();
3753
3754         register_trigger_cmds();
3755
3756         return 0;
3757 }
3758
3759 /*
3760  * event_trace_enable() is called from trace_event_init() first to
3761  * initialize events and perhaps start any events that are on the
3762  * command line. Unfortunately, there are some events that will not
3763  * start this early, like the system call tracepoints that need
3764  * to set the %SYSCALL_WORK_SYSCALL_TRACEPOINT flag of pid 1. But
3765  * event_trace_enable() is called before pid 1 starts, and this flag
3766  * is never set, making the syscall tracepoint never get reached, but
3767  * the event is enabled regardless (and not doing anything).
3768  */
3769 static __init int event_trace_enable_again(void)
3770 {
3771         struct trace_array *tr;
3772
3773         tr = top_trace_array();
3774         if (!tr)
3775                 return -ENODEV;
3776
3777         early_enable_events(tr, true);
3778
3779         return 0;
3780 }
3781
3782 early_initcall(event_trace_enable_again);
3783
3784 /* Init fields which doesn't related to the tracefs */
3785 static __init int event_trace_init_fields(void)
3786 {
3787         if (trace_define_generic_fields())
3788                 pr_warn("tracing: Failed to allocated generic fields");
3789
3790         if (trace_define_common_fields())
3791                 pr_warn("tracing: Failed to allocate common fields");
3792
3793         return 0;
3794 }
3795
3796 __init int event_trace_init(void)
3797 {
3798         struct trace_array *tr;
3799         struct dentry *entry;
3800         int ret;
3801
3802         tr = top_trace_array();
3803         if (!tr)
3804                 return -ENODEV;
3805
3806         entry = tracefs_create_file("available_events", TRACE_MODE_READ,
3807                                     NULL, tr, &ftrace_avail_fops);
3808         if (!entry)
3809                 pr_warn("Could not create tracefs 'available_events' entry\n");
3810
3811         ret = early_event_add_tracer(NULL, tr);
3812         if (ret)
3813                 return ret;
3814
3815 #ifdef CONFIG_MODULES
3816         ret = register_module_notifier(&trace_module_nb);
3817         if (ret)
3818                 pr_warn("Failed to register trace events module notifier\n");
3819 #endif
3820
3821         eventdir_initialized = true;
3822
3823         return 0;
3824 }
3825
3826 void __init trace_event_init(void)
3827 {
3828         event_trace_memsetup();
3829         init_ftrace_syscalls();
3830         event_trace_enable();
3831         event_trace_init_fields();
3832 }
3833
3834 #ifdef CONFIG_EVENT_TRACE_STARTUP_TEST
3835
3836 static DEFINE_SPINLOCK(test_spinlock);
3837 static DEFINE_SPINLOCK(test_spinlock_irq);
3838 static DEFINE_MUTEX(test_mutex);
3839
3840 static __init void test_work(struct work_struct *dummy)
3841 {
3842         spin_lock(&test_spinlock);
3843         spin_lock_irq(&test_spinlock_irq);
3844         udelay(1);
3845         spin_unlock_irq(&test_spinlock_irq);
3846         spin_unlock(&test_spinlock);
3847
3848         mutex_lock(&test_mutex);
3849         msleep(1);
3850         mutex_unlock(&test_mutex);
3851 }
3852
3853 static __init int event_test_thread(void *unused)
3854 {
3855         void *test_malloc;
3856
3857         test_malloc = kmalloc(1234, GFP_KERNEL);
3858         if (!test_malloc)
3859                 pr_info("failed to kmalloc\n");
3860
3861         schedule_on_each_cpu(test_work);
3862
3863         kfree(test_malloc);
3864
3865         set_current_state(TASK_INTERRUPTIBLE);
3866         while (!kthread_should_stop()) {
3867                 schedule();
3868                 set_current_state(TASK_INTERRUPTIBLE);
3869         }
3870         __set_current_state(TASK_RUNNING);
3871
3872         return 0;
3873 }
3874
3875 /*
3876  * Do various things that may trigger events.
3877  */
3878 static __init void event_test_stuff(void)
3879 {
3880         struct task_struct *test_thread;
3881
3882         test_thread = kthread_run(event_test_thread, NULL, "test-events");
3883         msleep(1);
3884         kthread_stop(test_thread);
3885 }
3886
3887 /*
3888  * For every trace event defined, we will test each trace point separately,
3889  * and then by groups, and finally all trace points.
3890  */
3891 static __init void event_trace_self_tests(void)
3892 {
3893         struct trace_subsystem_dir *dir;
3894         struct trace_event_file *file;
3895         struct trace_event_call *call;
3896         struct event_subsystem *system;
3897         struct trace_array *tr;
3898         int ret;
3899
3900         tr = top_trace_array();
3901         if (!tr)
3902                 return;
3903
3904         pr_info("Running tests on trace events:\n");
3905
3906         list_for_each_entry(file, &tr->events, list) {
3907
3908                 call = file->event_call;
3909
3910                 /* Only test those that have a probe */
3911                 if (!call->class || !call->class->probe)
3912                         continue;
3913
3914 /*
3915  * Testing syscall events here is pretty useless, but
3916  * we still do it if configured. But this is time consuming.
3917  * What we really need is a user thread to perform the
3918  * syscalls as we test.
3919  */
3920 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
3921                 if (call->class->system &&
3922                     strcmp(call->class->system, "syscalls") == 0)
3923                         continue;
3924 #endif
3925
3926                 pr_info("Testing event %s: ", trace_event_name(call));
3927
3928                 /*
3929                  * If an event is already enabled, someone is using
3930                  * it and the self test should not be on.
3931                  */
3932                 if (file->flags & EVENT_FILE_FL_ENABLED) {
3933                         pr_warn("Enabled event during self test!\n");
3934                         WARN_ON_ONCE(1);
3935                         continue;
3936                 }
3937
3938                 ftrace_event_enable_disable(file, 1);
3939                 event_test_stuff();
3940                 ftrace_event_enable_disable(file, 0);
3941
3942                 pr_cont("OK\n");
3943         }
3944
3945         /* Now test at the sub system level */
3946
3947         pr_info("Running tests on trace event systems:\n");
3948
3949         list_for_each_entry(dir, &tr->systems, list) {
3950
3951                 system = dir->subsystem;
3952
3953                 /* the ftrace system is special, skip it */
3954                 if (strcmp(system->name, "ftrace") == 0)
3955                         continue;
3956
3957                 pr_info("Testing event system %s: ", system->name);
3958
3959                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
3960                 if (WARN_ON_ONCE(ret)) {
3961                         pr_warn("error enabling system %s\n",
3962                                 system->name);
3963                         continue;
3964                 }
3965
3966                 event_test_stuff();
3967
3968                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
3969                 if (WARN_ON_ONCE(ret)) {
3970                         pr_warn("error disabling system %s\n",
3971                                 system->name);
3972                         continue;
3973                 }
3974
3975                 pr_cont("OK\n");
3976         }
3977
3978         /* Test with all events enabled */
3979
3980         pr_info("Running tests on all trace events:\n");
3981         pr_info("Testing all events: ");
3982
3983         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
3984         if (WARN_ON_ONCE(ret)) {
3985                 pr_warn("error enabling all events\n");
3986                 return;
3987         }
3988
3989         event_test_stuff();
3990
3991         /* reset sysname */
3992         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
3993         if (WARN_ON_ONCE(ret)) {
3994                 pr_warn("error disabling all events\n");
3995                 return;
3996         }
3997
3998         pr_cont("OK\n");
3999 }
4000
4001 #ifdef CONFIG_FUNCTION_TRACER
4002
4003 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
4004
4005 static struct trace_event_file event_trace_file __initdata;
4006
4007 static void __init
4008 function_test_events_call(unsigned long ip, unsigned long parent_ip,
4009                           struct ftrace_ops *op, struct ftrace_regs *regs)
4010 {
4011         struct trace_buffer *buffer;
4012         struct ring_buffer_event *event;
4013         struct ftrace_entry *entry;
4014         unsigned int trace_ctx;
4015         long disabled;
4016         int cpu;
4017
4018         trace_ctx = tracing_gen_ctx();
4019         preempt_disable_notrace();
4020         cpu = raw_smp_processor_id();
4021         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
4022
4023         if (disabled != 1)
4024                 goto out;
4025
4026         event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
4027                                                 TRACE_FN, sizeof(*entry),
4028                                                 trace_ctx);
4029         if (!event)
4030                 goto out;
4031         entry   = ring_buffer_event_data(event);
4032         entry->ip                       = ip;
4033         entry->parent_ip                = parent_ip;
4034
4035         event_trigger_unlock_commit(&event_trace_file, buffer, event,
4036                                     entry, trace_ctx);
4037  out:
4038         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
4039         preempt_enable_notrace();
4040 }
4041
4042 static struct ftrace_ops trace_ops __initdata  =
4043 {
4044         .func = function_test_events_call,
4045 };
4046
4047 static __init void event_trace_self_test_with_function(void)
4048 {
4049         int ret;
4050
4051         event_trace_file.tr = top_trace_array();
4052         if (WARN_ON(!event_trace_file.tr))
4053                 return;
4054
4055         ret = register_ftrace_function(&trace_ops);
4056         if (WARN_ON(ret < 0)) {
4057                 pr_info("Failed to enable function tracer for event tests\n");
4058                 return;
4059         }
4060         pr_info("Running tests again, along with the function tracer\n");
4061         event_trace_self_tests();
4062         unregister_ftrace_function(&trace_ops);
4063 }
4064 #else
4065 static __init void event_trace_self_test_with_function(void)
4066 {
4067 }
4068 #endif
4069
4070 static __init int event_trace_self_tests_init(void)
4071 {
4072         if (!tracing_selftest_disabled) {
4073                 event_trace_self_tests();
4074                 event_trace_self_test_with_function();
4075         }
4076
4077         return 0;
4078 }
4079
4080 late_initcall(event_trace_self_tests_init);
4081
4082 #endif