kernel/trace/trace_events.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * event tracer
   4  *
   5  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
   6  *
   7  *  - Added format output of fields of the trace point.
   8  *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
   9  *
  10  */
  11
  12 #define pr_fmt(fmt) fmt
  13
  14 #include <linux/workqueue.h>
  15 #include <linux/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, int len)
 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         field->len = len;
 137
 138         list_add(&field->link, head);
 139
 140         return 0;
 141 }
 142
 143 int trace_define_field(struct trace_event_call *call, const char *type,
 144                        const char *name, int offset, int size, int is_signed,
 145                        int filter_type)
 146 {
 147         struct list_head *head;
 148
 149         if (WARN_ON(!call->class))
 150                 return 0;
 151
 152         head = trace_get_fields(call);
 153         return __trace_define_field(head, type, name, offset, size,
 154                                     is_signed, filter_type, 0);
 155 }
 156 EXPORT_SYMBOL_GPL(trace_define_field);
 157
 158 static int trace_define_field_ext(struct trace_event_call *call, const char *type,
 159                        const char *name, int offset, int size, int is_signed,
 160                        int filter_type, int len)
 161 {
 162         struct list_head *head;
 163
 164         if (WARN_ON(!call->class))
 165                 return 0;
 166
 167         head = trace_get_fields(call);
 168         return __trace_define_field(head, type, name, offset, size,
 169                                     is_signed, filter_type, len);
 170 }
 171
 172 #define __generic_field(type, item, filter_type)                        \
 173         ret = __trace_define_field(&ftrace_generic_fields, #type,       \
 174                                    #item, 0, 0, is_signed_type(type),   \
 175                                    filter_type, 0);                     \
 176         if (ret)                                                        \
 177                 return ret;
 178
 179 #define __common_field(type, item)                                      \
 180         ret = __trace_define_field(&ftrace_common_fields, #type,        \
 181                                    "common_" #item,                     \
 182                                    offsetof(typeof(ent), item),         \
 183                                    sizeof(ent.item),                    \
 184                                    is_signed_type(type), FILTER_OTHER, 0);      \
 185         if (ret)                                                        \
 186                 return ret;
 187
 188 static int trace_define_generic_fields(void)
 189 {
 190         int ret;
 191
 192         __generic_field(int, CPU, FILTER_CPU);
 193         __generic_field(int, cpu, FILTER_CPU);
 194         __generic_field(int, common_cpu, FILTER_CPU);
 195         __generic_field(char *, COMM, FILTER_COMM);
 196         __generic_field(char *, comm, FILTER_COMM);
 197         __generic_field(char *, stacktrace, FILTER_STACKTRACE);
 198         __generic_field(char *, STACKTRACE, FILTER_STACKTRACE);
 199
 200         return ret;
 201 }
 202
 203 static int trace_define_common_fields(void)
 204 {
 205         int ret;
 206         struct trace_entry ent;
 207
 208         __common_field(unsigned short, type);
 209         __common_field(unsigned char, flags);
 210         /* Holds both preempt_count and migrate_disable */
 211         __common_field(unsigned char, preempt_count);
 212         __common_field(int, pid);
 213
 214         return ret;
 215 }
 216
 217 static void trace_destroy_fields(struct trace_event_call *call)
 218 {
 219         struct ftrace_event_field *field, *next;
 220         struct list_head *head;
 221
 222         head = trace_get_fields(call);
 223         list_for_each_entry_safe(field, next, head, link) {
 224                 list_del(&field->link);
 225                 kmem_cache_free(field_cachep, field);
 226         }
 227 }
 228
 229 /*
 230  * run-time version of trace_event_get_offsets_<call>() that returns the last
 231  * accessible offset of trace fields excluding __dynamic_array bytes
 232  */
 233 int trace_event_get_offsets(struct trace_event_call *call)
 234 {
 235         struct ftrace_event_field *tail;
 236         struct list_head *head;
 237
 238         head = trace_get_fields(call);
 239         /*
 240          * head->next points to the last field with the largest offset,
 241          * since it was added last by trace_define_field()
 242          */
 243         tail = list_first_entry(head, struct ftrace_event_field, link);
 244         return tail->offset + tail->size;
 245 }
 246
 247 /*
 248  * Check if the referenced field is an array and return true,
 249  * as arrays are OK to dereference.
 250  */
 251 static bool test_field(const char *fmt, struct trace_event_call *call)
 252 {
 253         struct trace_event_fields *field = call->class->fields_array;
 254         const char *array_descriptor;
 255         const char *p = fmt;
 256         int len;
 257
 258         if (!(len = str_has_prefix(fmt, "REC->")))
 259                 return false;
 260         fmt += len;
 261         for (p = fmt; *p; p++) {
 262                 if (!isalnum(*p) && *p != '_')
 263                         break;
 264         }
 265         len = p - fmt;
 266
 267         for (; field->type; field++) {
 268                 if (strncmp(field->name, fmt, len) ||
 269                     field->name[len])
 270                         continue;
 271                 array_descriptor = strchr(field->type, '[');
 272                 /* This is an array and is OK to dereference. */
 273                 return array_descriptor != NULL;
 274         }
 275         return false;
 276 }
 277
 278 /*
 279  * Examine the print fmt of the event looking for unsafe dereference
 280  * pointers using %p* that could be recorded in the trace event and
 281  * much later referenced after the pointer was freed. Dereferencing
 282  * pointers are OK, if it is dereferenced into the event itself.
 283  */
 284 static void test_event_printk(struct trace_event_call *call)
 285 {
 286         u64 dereference_flags = 0;
 287         bool first = true;
 288         const char *fmt, *c, *r, *a;
 289         int parens = 0;
 290         char in_quote = 0;
 291         int start_arg = 0;
 292         int arg = 0;
 293         int i;
 294
 295         fmt = call->print_fmt;
 296
 297         if (!fmt)
 298                 return;
 299
 300         for (i = 0; fmt[i]; i++) {
 301                 switch (fmt[i]) {
 302                 case '\\':
 303                         i++;
 304                         if (!fmt[i])
 305                                 return;
 306                         continue;
 307                 case '"':
 308                 case '\'':
 309                         /*
 310                          * The print fmt starts with a string that
 311                          * is processed first to find %p* usage,
 312                          * then after the first string, the print fmt
 313                          * contains arguments that are used to check
 314                          * if the dereferenced %p* usage is safe.
 315                          */
 316                         if (first) {
 317                                 if (fmt[i] == '\'')
 318                                         continue;
 319                                 if (in_quote) {
 320                                         arg = 0;
 321                                         first = false;
 322                                         /*
 323                                          * If there was no %p* uses
 324                                          * the fmt is OK.
 325                                          */
 326                                         if (!dereference_flags)
 327                                                 return;
 328                                 }
 329                         }
 330                         if (in_quote) {
 331                                 if (in_quote == fmt[i])
 332                                         in_quote = 0;
 333                         } else {
 334                                 in_quote = fmt[i];
 335                         }
 336                         continue;
 337                 case '%':
 338                         if (!first || !in_quote)
 339                                 continue;
 340                         i++;
 341                         if (!fmt[i])
 342                                 return;
 343                         switch (fmt[i]) {
 344                         case '%':
 345                                 continue;
 346                         case 'p':
 347                                 /* Find dereferencing fields */
 348                                 switch (fmt[i + 1]) {
 349                                 case 'B': case 'R': case 'r':
 350                                 case 'b': case 'M': case 'm':
 351                                 case 'I': case 'i': case 'E':
 352                                 case 'U': case 'V': case 'N':
 353                                 case 'a': case 'd': case 'D':
 354                                 case 'g': case 't': case 'C':
 355                                 case 'O': case 'f':
 356                                         if (WARN_ONCE(arg == 63,
 357                                                       "Too many args for event: %s",
 358                                                       trace_event_name(call)))
 359                                                 return;
 360                                         dereference_flags |= 1ULL << arg;
 361                                 }
 362                                 break;
 363                         default:
 364                         {
 365                                 bool star = false;
 366                                 int j;
 367
 368                                 /* Increment arg if %*s exists. */
 369                                 for (j = 0; fmt[i + j]; j++) {
 370                                         if (isdigit(fmt[i + j]) ||
 371                                             fmt[i + j] == '.')
 372                                                 continue;
 373                                         if (fmt[i + j] == '*') {
 374                                                 star = true;
 375                                                 continue;
 376                                         }
 377                                         if ((fmt[i + j] == 's') && star)
 378                                                 arg++;
 379                                         break;
 380                                 }
 381                                 break;
 382                         } /* default */
 383
 384                         } /* switch */
 385                         arg++;
 386                         continue;
 387                 case '(':
 388                         if (in_quote)
 389                                 continue;
 390                         parens++;
 391                         continue;
 392                 case ')':
 393                         if (in_quote)
 394                                 continue;
 395                         parens--;
 396                         if (WARN_ONCE(parens < 0,
 397                                       "Paren mismatch for event: %s\narg='%s'\n%*s",
 398                                       trace_event_name(call),
 399                                       fmt + start_arg,
 400                                       (i - start_arg) + 5, "^"))
 401                                 return;
 402                         continue;
 403                 case ',':
 404                         if (in_quote || parens)
 405                                 continue;
 406                         i++;
 407                         while (isspace(fmt[i]))
 408                                 i++;
 409                         start_arg = i;
 410                         if (!(dereference_flags & (1ULL << arg)))
 411                                 goto next_arg;
 412
 413                         /* Find the REC-> in the argument */
 414                         c = strchr(fmt + i, ',');
 415                         r = strstr(fmt + i, "REC->");
 416                         if (r && (!c || r < c)) {
 417                                 /*
 418                                  * Addresses of events on the buffer,
 419                                  * or an array on the buffer is
 420                                  * OK to dereference.
 421                                  * There's ways to fool this, but
 422                                  * this is to catch common mistakes,
 423                                  * not malicious code.
 424                                  */
 425                                 a = strchr(fmt + i, '&');
 426                                 if ((a && (a < r)) || test_field(r, call))
 427                                         dereference_flags &= ~(1ULL << arg);
 428                         } else if ((r = strstr(fmt + i, "__get_dynamic_array(")) &&
 429                                    (!c || r < c)) {
 430                                 dereference_flags &= ~(1ULL << arg);
 431                         } else if ((r = strstr(fmt + i, "__get_sockaddr(")) &&
 432                                    (!c || r < c)) {
 433                                 dereference_flags &= ~(1ULL << arg);
 434                         }
 435
 436                 next_arg:
 437                         i--;
 438                         arg++;
 439                 }
 440         }
 441
 442         /*
 443          * If you triggered the below warning, the trace event reported
 444          * uses an unsafe dereference pointer %p*. As the data stored
 445          * at the trace event time may no longer exist when the trace
 446          * event is printed, dereferencing to the original source is
 447          * unsafe. The source of the dereference must be copied into the
 448          * event itself, and the dereference must access the copy instead.
 449          */
 450         if (WARN_ON_ONCE(dereference_flags)) {
 451                 arg = 1;
 452                 while (!(dereference_flags & 1)) {
 453                         dereference_flags >>= 1;
 454                         arg++;
 455                 }
 456                 pr_warn("event %s has unsafe dereference of argument %d\n",
 457                         trace_event_name(call), arg);
 458                 pr_warn("print_fmt: %s\n", fmt);
 459         }
 460 }
 461
 462 int trace_event_raw_init(struct trace_event_call *call)
 463 {
 464         int id;
 465
 466         id = register_trace_event(&call->event);
 467         if (!id)
 468                 return -ENODEV;
 469
 470         test_event_printk(call);
 471
 472         return 0;
 473 }
 474 EXPORT_SYMBOL_GPL(trace_event_raw_init);
 475
 476 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
 477 {
 478         struct trace_array *tr = trace_file->tr;
 479         struct trace_array_cpu *data;
 480         struct trace_pid_list *no_pid_list;
 481         struct trace_pid_list *pid_list;
 482
 483         pid_list = rcu_dereference_raw(tr->filtered_pids);
 484         no_pid_list = rcu_dereference_raw(tr->filtered_no_pids);
 485
 486         if (!pid_list && !no_pid_list)
 487                 return false;
 488
 489         data = this_cpu_ptr(tr->array_buffer.data);
 490
 491         return data->ignore_pid;
 492 }
 493 EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
 494
 495 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 496                                  struct trace_event_file *trace_file,
 497                                  unsigned long len)
 498 {
 499         struct trace_event_call *event_call = trace_file->event_call;
 500
 501         if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
 502             trace_event_ignore_this_pid(trace_file))
 503                 return NULL;
 504
 505         /*
 506          * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
 507          * preemption (adding one to the preempt_count). Since we are
 508          * interested in the preempt_count at the time the tracepoint was
 509          * hit, we need to subtract one to offset the increment.
 510          */
 511         fbuffer->trace_ctx = tracing_gen_ctx_dec();
 512         fbuffer->trace_file = trace_file;
 513
 514         fbuffer->event =
 515                 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
 516                                                 event_call->event.type, len,
 517                                                 fbuffer->trace_ctx);
 518         if (!fbuffer->event)
 519                 return NULL;
 520
 521         fbuffer->regs = NULL;
 522         fbuffer->entry = ring_buffer_event_data(fbuffer->event);
 523         return fbuffer->entry;
 524 }
 525 EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
 526
 527 int trace_event_reg(struct trace_event_call *call,
 528                     enum trace_reg type, void *data)
 529 {
 530         struct trace_event_file *file = data;
 531
 532         WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
 533         switch (type) {
 534         case TRACE_REG_REGISTER:
 535                 return tracepoint_probe_register(call->tp,
 536                                                  call->class->probe,
 537                                                  file);
 538         case TRACE_REG_UNREGISTER:
 539                 tracepoint_probe_unregister(call->tp,
 540                                             call->class->probe,
 541                                             file);
 542                 return 0;
 543
 544 #ifdef CONFIG_PERF_EVENTS
 545         case TRACE_REG_PERF_REGISTER:
 546                 return tracepoint_probe_register(call->tp,
 547                                                  call->class->perf_probe,
 548                                                  call);
 549         case TRACE_REG_PERF_UNREGISTER:
 550                 tracepoint_probe_unregister(call->tp,
 551                                             call->class->perf_probe,
 552                                             call);
 553                 return 0;
 554         case TRACE_REG_PERF_OPEN:
 555         case TRACE_REG_PERF_CLOSE:
 556         case TRACE_REG_PERF_ADD:
 557         case TRACE_REG_PERF_DEL:
 558                 return 0;
 559 #endif
 560         }
 561         return 0;
 562 }
 563 EXPORT_SYMBOL_GPL(trace_event_reg);
 564
 565 void trace_event_enable_cmd_record(bool enable)
 566 {
 567         struct trace_event_file *file;
 568         struct trace_array *tr;
 569
 570         lockdep_assert_held(&event_mutex);
 571
 572         do_for_each_event_file(tr, file) {
 573
 574                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
 575                         continue;
 576
 577                 if (enable) {
 578                         tracing_start_cmdline_record();
 579                         set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 580                 } else {
 581                         tracing_stop_cmdline_record();
 582                         clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 583                 }
 584         } while_for_each_event_file();
 585 }
 586
 587 void trace_event_enable_tgid_record(bool enable)
 588 {
 589         struct trace_event_file *file;
 590         struct trace_array *tr;
 591
 592         lockdep_assert_held(&event_mutex);
 593
 594         do_for_each_event_file(tr, file) {
 595                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
 596                         continue;
 597
 598                 if (enable) {
 599                         tracing_start_tgid_record();
 600                         set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 601                 } else {
 602                         tracing_stop_tgid_record();
 603                         clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
 604                                   &file->flags);
 605                 }
 606         } while_for_each_event_file();
 607 }
 608
 609 static int __ftrace_event_enable_disable(struct trace_event_file *file,
 610                                          int enable, int soft_disable)
 611 {
 612         struct trace_event_call *call = file->event_call;
 613         struct trace_array *tr = file->tr;
 614         int ret = 0;
 615         int disable;
 616
 617         switch (enable) {
 618         case 0:
 619                 /*
 620                  * When soft_disable is set and enable is cleared, the sm_ref
 621                  * reference counter is decremented. If it reaches 0, we want
 622                  * to clear the SOFT_DISABLED flag but leave the event in the
 623                  * state that it was. That is, if the event was enabled and
 624                  * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
 625                  * is set we do not want the event to be enabled before we
 626                  * clear the bit.
 627                  *
 628                  * When soft_disable is not set but the SOFT_MODE flag is,
 629                  * we do nothing. Do not disable the tracepoint, otherwise
 630                  * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
 631                  */
 632                 if (soft_disable) {
 633                         if (atomic_dec_return(&file->sm_ref) > 0)
 634                                 break;
 635                         disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
 636                         clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 637                         /* Disable use of trace_buffered_event */
 638                         trace_buffered_event_disable();
 639                 } else
 640                         disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
 641
 642                 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
 643                         clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 644                         if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
 645                                 tracing_stop_cmdline_record();
 646                                 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 647                         }
 648
 649                         if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
 650                                 tracing_stop_tgid_record();
 651                                 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 652                         }
 653
 654                         call->class->reg(call, TRACE_REG_UNREGISTER, file);
 655                 }
 656                 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
 657                 if (file->flags & EVENT_FILE_FL_SOFT_MODE)
 658                         set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 659                 else
 660                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 661                 break;
 662         case 1:
 663                 /*
 664                  * When soft_disable is set and enable is set, we want to
 665                  * register the tracepoint for the event, but leave the event
 666                  * as is. That means, if the event was already enabled, we do
 667                  * nothing (but set SOFT_MODE). If the event is disabled, we
 668                  * set SOFT_DISABLED before enabling the event tracepoint, so
 669                  * it still seems to be disabled.
 670                  */
 671                 if (!soft_disable)
 672                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 673                 else {
 674                         if (atomic_inc_return(&file->sm_ref) > 1)
 675                                 break;
 676                         set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 677                         /* Enable use of trace_buffered_event */
 678                         trace_buffered_event_enable();
 679                 }
 680
 681                 if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
 682                         bool cmd = false, tgid = false;
 683
 684                         /* Keep the event disabled, when going to SOFT_MODE. */
 685                         if (soft_disable)
 686                                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 687
 688                         if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
 689                                 cmd = true;
 690                                 tracing_start_cmdline_record();
 691                                 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 692                         }
 693
 694                         if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
 695                                 tgid = true;
 696                                 tracing_start_tgid_record();
 697                                 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 698                         }
 699
 700                         ret = call->class->reg(call, TRACE_REG_REGISTER, file);
 701                         if (ret) {
 702                                 if (cmd)
 703                                         tracing_stop_cmdline_record();
 704                                 if (tgid)
 705                                         tracing_stop_tgid_record();
 706                                 pr_info("event trace: Could not enable event "
 707                                         "%s\n", trace_event_name(call));
 708                                 break;
 709                         }
 710                         set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 711
 712                         /* WAS_ENABLED gets set but never cleared. */
 713                         set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
 714                 }
 715                 break;
 716         }
 717
 718         return ret;
 719 }
 720
 721 int trace_event_enable_disable(struct trace_event_file *file,
 722                                int enable, int soft_disable)
 723 {
 724         return __ftrace_event_enable_disable(file, enable, soft_disable);
 725 }
 726
 727 static int ftrace_event_enable_disable(struct trace_event_file *file,
 728                                        int enable)
 729 {
 730         return __ftrace_event_enable_disable(file, enable, 0);
 731 }
 732
 733 static void ftrace_clear_events(struct trace_array *tr)
 734 {
 735         struct trace_event_file *file;
 736
 737         mutex_lock(&event_mutex);
 738         list_for_each_entry(file, &tr->events, list) {
 739                 ftrace_event_enable_disable(file, 0);
 740         }
 741         mutex_unlock(&event_mutex);
 742 }
 743
 744 static void
 745 event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
 746 {
 747         struct trace_pid_list *pid_list;
 748         struct trace_array *tr = data;
 749
 750         pid_list = rcu_dereference_raw(tr->filtered_pids);
 751         trace_filter_add_remove_task(pid_list, NULL, task);
 752
 753         pid_list = rcu_dereference_raw(tr->filtered_no_pids);
 754         trace_filter_add_remove_task(pid_list, NULL, task);
 755 }
 756
 757 static void
 758 event_filter_pid_sched_process_fork(void *data,
 759                                     struct task_struct *self,
 760                                     struct task_struct *task)
 761 {
 762         struct trace_pid_list *pid_list;
 763         struct trace_array *tr = data;
 764
 765         pid_list = rcu_dereference_sched(tr->filtered_pids);
 766         trace_filter_add_remove_task(pid_list, self, task);
 767
 768         pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 769         trace_filter_add_remove_task(pid_list, self, task);
 770 }
 771
 772 void trace_event_follow_fork(struct trace_array *tr, bool enable)
 773 {
 774         if (enable) {
 775                 register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
 776                                                        tr, INT_MIN);
 777                 register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
 778                                                        tr, INT_MAX);
 779         } else {
 780                 unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
 781                                                     tr);
 782                 unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
 783                                                     tr);
 784         }
 785 }
 786
 787 static void
 788 event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
 789                                         struct task_struct *prev,
 790                                         struct task_struct *next,
 791                                         unsigned int prev_state)
 792 {
 793         struct trace_array *tr = data;
 794         struct trace_pid_list *no_pid_list;
 795         struct trace_pid_list *pid_list;
 796         bool ret;
 797
 798         pid_list = rcu_dereference_sched(tr->filtered_pids);
 799         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 800
 801         /*
 802          * Sched switch is funny, as we only want to ignore it
 803          * in the notrace case if both prev and next should be ignored.
 804          */
 805         ret = trace_ignore_this_task(NULL, no_pid_list, prev) &&
 806                 trace_ignore_this_task(NULL, no_pid_list, next);
 807
 808         this_cpu_write(tr->array_buffer.data->ignore_pid, ret ||
 809                        (trace_ignore_this_task(pid_list, NULL, prev) &&
 810                         trace_ignore_this_task(pid_list, NULL, next)));
 811 }
 812
 813 static void
 814 event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
 815                                          struct task_struct *prev,
 816                                          struct task_struct *next,
 817                                          unsigned int prev_state)
 818 {
 819         struct trace_array *tr = data;
 820         struct trace_pid_list *no_pid_list;
 821         struct trace_pid_list *pid_list;
 822
 823         pid_list = rcu_dereference_sched(tr->filtered_pids);
 824         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 825
 826         this_cpu_write(tr->array_buffer.data->ignore_pid,
 827                        trace_ignore_this_task(pid_list, no_pid_list, next));
 828 }
 829
 830 static void
 831 event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
 832 {
 833         struct trace_array *tr = data;
 834         struct trace_pid_list *no_pid_list;
 835         struct trace_pid_list *pid_list;
 836
 837         /* Nothing to do if we are already tracing */
 838         if (!this_cpu_read(tr->array_buffer.data->ignore_pid))
 839                 return;
 840
 841         pid_list = rcu_dereference_sched(tr->filtered_pids);
 842         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 843
 844         this_cpu_write(tr->array_buffer.data->ignore_pid,
 845                        trace_ignore_this_task(pid_list, no_pid_list, task));
 846 }
 847
 848 static void
 849 event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
 850 {
 851         struct trace_array *tr = data;
 852         struct trace_pid_list *no_pid_list;
 853         struct trace_pid_list *pid_list;
 854
 855         /* Nothing to do if we are not tracing */
 856         if (this_cpu_read(tr->array_buffer.data->ignore_pid))
 857                 return;
 858
 859         pid_list = rcu_dereference_sched(tr->filtered_pids);
 860         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 861
 862         /* Set tracing if current is enabled */
 863         this_cpu_write(tr->array_buffer.data->ignore_pid,
 864                        trace_ignore_this_task(pid_list, no_pid_list, current));
 865 }
 866
 867 static void unregister_pid_events(struct trace_array *tr)
 868 {
 869         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
 870         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
 871
 872         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
 873         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
 874
 875         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
 876         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
 877
 878         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
 879         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
 880 }
 881
 882 static void __ftrace_clear_event_pids(struct trace_array *tr, int type)
 883 {
 884         struct trace_pid_list *pid_list;
 885         struct trace_pid_list *no_pid_list;
 886         struct trace_event_file *file;
 887         int cpu;
 888
 889         pid_list = rcu_dereference_protected(tr->filtered_pids,
 890                                              lockdep_is_held(&event_mutex));
 891         no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
 892                                              lockdep_is_held(&event_mutex));
 893
 894         /* Make sure there's something to do */
 895         if (!pid_type_enabled(type, pid_list, no_pid_list))
 896                 return;
 897
 898         if (!still_need_pid_events(type, pid_list, no_pid_list)) {
 899                 unregister_pid_events(tr);
 900
 901                 list_for_each_entry(file, &tr->events, list) {
 902                         clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
 903                 }
 904
 905                 for_each_possible_cpu(cpu)
 906                         per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
 907         }
 908
 909         if (type & TRACE_PIDS)
 910                 rcu_assign_pointer(tr->filtered_pids, NULL);
 911
 912         if (type & TRACE_NO_PIDS)
 913                 rcu_assign_pointer(tr->filtered_no_pids, NULL);
 914
 915         /* Wait till all users are no longer using pid filtering */
 916         tracepoint_synchronize_unregister();
 917
 918         if ((type & TRACE_PIDS) && pid_list)
 919                 trace_pid_list_free(pid_list);
 920
 921         if ((type & TRACE_NO_PIDS) && no_pid_list)
 922                 trace_pid_list_free(no_pid_list);
 923 }
 924
 925 static void ftrace_clear_event_pids(struct trace_array *tr, int type)
 926 {
 927         mutex_lock(&event_mutex);
 928         __ftrace_clear_event_pids(tr, type);
 929         mutex_unlock(&event_mutex);
 930 }
 931
 932 static void __put_system(struct event_subsystem *system)
 933 {
 934         struct event_filter *filter = system->filter;
 935
 936         WARN_ON_ONCE(system_refcount(system) == 0);
 937         if (system_refcount_dec(system))
 938                 return;
 939
 940         list_del(&system->list);
 941
 942         if (filter) {
 943                 kfree(filter->filter_string);
 944                 kfree(filter);
 945         }
 946         kfree_const(system->name);
 947         kfree(system);
 948 }
 949
 950 static void __get_system(struct event_subsystem *system)
 951 {
 952         WARN_ON_ONCE(system_refcount(system) == 0);
 953         system_refcount_inc(system);
 954 }
 955
 956 static void __get_system_dir(struct trace_subsystem_dir *dir)
 957 {
 958         WARN_ON_ONCE(dir->ref_count == 0);
 959         dir->ref_count++;
 960         __get_system(dir->subsystem);
 961 }
 962
 963 static void __put_system_dir(struct trace_subsystem_dir *dir)
 964 {
 965         WARN_ON_ONCE(dir->ref_count == 0);
 966         /* If the subsystem is about to be freed, the dir must be too */
 967         WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
 968
 969         __put_system(dir->subsystem);
 970         if (!--dir->ref_count)
 971                 kfree(dir);
 972 }
 973
 974 static void put_system(struct trace_subsystem_dir *dir)
 975 {
 976         mutex_lock(&event_mutex);
 977         __put_system_dir(dir);
 978         mutex_unlock(&event_mutex);
 979 }
 980
 981 static void remove_subsystem(struct trace_subsystem_dir *dir)
 982 {
 983         if (!dir)
 984                 return;
 985
 986         if (!--dir->nr_events) {
 987                 eventfs_remove_dir(dir->ei);
 988                 list_del(&dir->list);
 989                 __put_system_dir(dir);
 990         }
 991 }
 992
 993 void event_file_get(struct trace_event_file *file)
 994 {
 995         refcount_inc(&file->ref);
 996 }
 997
 998 void event_file_put(struct trace_event_file *file)
 999 {
1000         if (WARN_ON_ONCE(!refcount_read(&file->ref))) {
1001                 if (file->flags & EVENT_FILE_FL_FREED)
1002                         kmem_cache_free(file_cachep, file);
1003                 return;
1004         }
1005
1006         if (refcount_dec_and_test(&file->ref)) {
1007                 /* Count should only go to zero when it is freed */
1008                 if (WARN_ON_ONCE(!(file->flags & EVENT_FILE_FL_FREED)))
1009                         return;
1010                 kmem_cache_free(file_cachep, file);
1011         }
1012 }
1013
1014 static void remove_event_file_dir(struct trace_event_file *file)
1015 {
1016         eventfs_remove_dir(file->ei);
1017         list_del(&file->list);
1018         remove_subsystem(file->system);
1019         free_event_filter(file->filter);
1020         file->flags |= EVENT_FILE_FL_FREED;
1021         event_file_put(file);
1022 }
1023
1024 /*
1025  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
1026  */
1027 static int
1028 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
1029                               const char *sub, const char *event, int set)
1030 {
1031         struct trace_event_file *file;
1032         struct trace_event_call *call;
1033         const char *name;
1034         int ret = -EINVAL;
1035         int eret = 0;
1036
1037         list_for_each_entry(file, &tr->events, list) {
1038
1039                 call = file->event_call;
1040                 name = trace_event_name(call);
1041
1042                 if (!name || !call->class || !call->class->reg)
1043                         continue;
1044
1045                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1046                         continue;
1047
1048                 if (match &&
1049                     strcmp(match, name) != 0 &&
1050                     strcmp(match, call->class->system) != 0)
1051                         continue;
1052
1053                 if (sub && strcmp(sub, call->class->system) != 0)
1054                         continue;
1055
1056                 if (event && strcmp(event, name) != 0)
1057                         continue;
1058
1059                 ret = ftrace_event_enable_disable(file, set);
1060
1061                 /*
1062                  * Save the first error and return that. Some events
1063                  * may still have been enabled, but let the user
1064                  * know that something went wrong.
1065                  */
1066                 if (ret && !eret)
1067                         eret = ret;
1068
1069                 ret = eret;
1070         }
1071
1072         return ret;
1073 }
1074
1075 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
1076                                   const char *sub, const char *event, int set)
1077 {
1078         int ret;
1079
1080         mutex_lock(&event_mutex);
1081         ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
1082         mutex_unlock(&event_mutex);
1083
1084         return ret;
1085 }
1086
1087 int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
1088 {
1089         char *event = NULL, *sub = NULL, *match;
1090         int ret;
1091
1092         if (!tr)
1093                 return -ENOENT;
1094         /*
1095          * The buf format can be <subsystem>:<event-name>
1096          *  *:<event-name> means any event by that name.
1097          *  :<event-name> is the same.
1098          *
1099          *  <subsystem>:* means all events in that subsystem
1100          *  <subsystem>: means the same.
1101          *
1102          *  <name> (no ':') means all events in a subsystem with
1103          *  the name <name> or any event that matches <name>
1104          */
1105
1106         match = strsep(&buf, ":");
1107         if (buf) {
1108                 sub = match;
1109                 event = buf;
1110                 match = NULL;
1111
1112                 if (!strlen(sub) || strcmp(sub, "*") == 0)
1113                         sub = NULL;
1114                 if (!strlen(event) || strcmp(event, "*") == 0)
1115                         event = NULL;
1116         }
1117
1118         ret = __ftrace_set_clr_event(tr, match, sub, event, set);
1119
1120         /* Put back the colon to allow this to be called again */
1121         if (buf)
1122                 *(buf - 1) = ':';
1123
1124         return ret;
1125 }
1126
1127 /**
1128  * trace_set_clr_event - enable or disable an event
1129  * @system: system name to match (NULL for any system)
1130  * @event: event name to match (NULL for all events, within system)
1131  * @set: 1 to enable, 0 to disable
1132  *
1133  * This is a way for other parts of the kernel to enable or disable
1134  * event recording.
1135  *
1136  * Returns 0 on success, -EINVAL if the parameters do not match any
1137  * registered events.
1138  */
1139 int trace_set_clr_event(const char *system, const char *event, int set)
1140 {
1141         struct trace_array *tr = top_trace_array();
1142
1143         if (!tr)
1144                 return -ENODEV;
1145
1146         return __ftrace_set_clr_event(tr, NULL, system, event, set);
1147 }
1148 EXPORT_SYMBOL_GPL(trace_set_clr_event);
1149
1150 /**
1151  * trace_array_set_clr_event - enable or disable an event for a trace array.
1152  * @tr: concerned trace array.
1153  * @system: system name to match (NULL for any system)
1154  * @event: event name to match (NULL for all events, within system)
1155  * @enable: true to enable, false to disable
1156  *
1157  * This is a way for other parts of the kernel to enable or disable
1158  * event recording.
1159  *
1160  * Returns 0 on success, -EINVAL if the parameters do not match any
1161  * registered events.
1162  */
1163 int trace_array_set_clr_event(struct trace_array *tr, const char *system,
1164                 const char *event, bool enable)
1165 {
1166         int set;
1167
1168         if (!tr)
1169                 return -ENOENT;
1170
1171         set = (enable == true) ? 1 : 0;
1172         return __ftrace_set_clr_event(tr, NULL, system, event, set);
1173 }
1174 EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
1175
1176 /* 128 should be much more than enough */
1177 #define EVENT_BUF_SIZE          127
1178
1179 static ssize_t
1180 ftrace_event_write(struct file *file, const char __user *ubuf,
1181                    size_t cnt, loff_t *ppos)
1182 {
1183         struct trace_parser parser;
1184         struct seq_file *m = file->private_data;
1185         struct trace_array *tr = m->private;
1186         ssize_t read, ret;
1187
1188         if (!cnt)
1189                 return 0;
1190
1191         ret = tracing_update_buffers(tr);
1192         if (ret < 0)
1193                 return ret;
1194
1195         if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
1196                 return -ENOMEM;
1197
1198         read = trace_get_user(&parser, ubuf, cnt, ppos);
1199
1200         if (read >= 0 && trace_parser_loaded((&parser))) {
1201                 int set = 1;
1202
1203                 if (*parser.buffer == '!')
1204                         set = 0;
1205
1206                 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
1207                 if (ret)
1208                         goto out_put;
1209         }
1210
1211         ret = read;
1212
1213  out_put:
1214         trace_parser_put(&parser);
1215
1216         return ret;
1217 }
1218
1219 static void *
1220 t_next(struct seq_file *m, void *v, loff_t *pos)
1221 {
1222         struct trace_event_file *file = v;
1223         struct trace_event_call *call;
1224         struct trace_array *tr = m->private;
1225
1226         (*pos)++;
1227
1228         list_for_each_entry_continue(file, &tr->events, list) {
1229                 call = file->event_call;
1230                 /*
1231                  * The ftrace subsystem is for showing formats only.
1232                  * They can not be enabled or disabled via the event files.
1233                  */
1234                 if (call->class && call->class->reg &&
1235                     !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1236                         return file;
1237         }
1238
1239         return NULL;
1240 }
1241
1242 static void *t_start(struct seq_file *m, loff_t *pos)
1243 {
1244         struct trace_event_file *file;
1245         struct trace_array *tr = m->private;
1246         loff_t l;
1247
1248         mutex_lock(&event_mutex);
1249
1250         file = list_entry(&tr->events, struct trace_event_file, list);
1251         for (l = 0; l <= *pos; ) {
1252                 file = t_next(m, file, &l);
1253                 if (!file)
1254                         break;
1255         }
1256         return file;
1257 }
1258
1259 static void *
1260 s_next(struct seq_file *m, void *v, loff_t *pos)
1261 {
1262         struct trace_event_file *file = v;
1263         struct trace_array *tr = m->private;
1264
1265         (*pos)++;
1266
1267         list_for_each_entry_continue(file, &tr->events, list) {
1268                 if (file->flags & EVENT_FILE_FL_ENABLED)
1269                         return file;
1270         }
1271
1272         return NULL;
1273 }
1274
1275 static void *s_start(struct seq_file *m, loff_t *pos)
1276 {
1277         struct trace_event_file *file;
1278         struct trace_array *tr = m->private;
1279         loff_t l;
1280
1281         mutex_lock(&event_mutex);
1282
1283         file = list_entry(&tr->events, struct trace_event_file, list);
1284         for (l = 0; l <= *pos; ) {
1285                 file = s_next(m, file, &l);
1286                 if (!file)
1287                         break;
1288         }
1289         return file;
1290 }
1291
1292 static int t_show(struct seq_file *m, void *v)
1293 {
1294         struct trace_event_file *file = v;
1295         struct trace_event_call *call = file->event_call;
1296
1297         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1298                 seq_printf(m, "%s:", call->class->system);
1299         seq_printf(m, "%s\n", trace_event_name(call));
1300
1301         return 0;
1302 }
1303
1304 static void t_stop(struct seq_file *m, void *p)
1305 {
1306         mutex_unlock(&event_mutex);
1307 }
1308
1309 static void *
1310 __next(struct seq_file *m, void *v, loff_t *pos, int type)
1311 {
1312         struct trace_array *tr = m->private;
1313         struct trace_pid_list *pid_list;
1314
1315         if (type == TRACE_PIDS)
1316                 pid_list = rcu_dereference_sched(tr->filtered_pids);
1317         else
1318                 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1319
1320         return trace_pid_next(pid_list, v, pos);
1321 }
1322
1323 static void *
1324 p_next(struct seq_file *m, void *v, loff_t *pos)
1325 {
1326         return __next(m, v, pos, TRACE_PIDS);
1327 }
1328
1329 static void *
1330 np_next(struct seq_file *m, void *v, loff_t *pos)
1331 {
1332         return __next(m, v, pos, TRACE_NO_PIDS);
1333 }
1334
1335 static void *__start(struct seq_file *m, loff_t *pos, int type)
1336         __acquires(RCU)
1337 {
1338         struct trace_pid_list *pid_list;
1339         struct trace_array *tr = m->private;
1340
1341         /*
1342          * Grab the mutex, to keep calls to p_next() having the same
1343          * tr->filtered_pids as p_start() has.
1344          * If we just passed the tr->filtered_pids around, then RCU would
1345          * have been enough, but doing that makes things more complex.
1346          */
1347         mutex_lock(&event_mutex);
1348         rcu_read_lock_sched();
1349
1350         if (type == TRACE_PIDS)
1351                 pid_list = rcu_dereference_sched(tr->filtered_pids);
1352         else
1353                 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1354
1355         if (!pid_list)
1356                 return NULL;
1357
1358         return trace_pid_start(pid_list, pos);
1359 }
1360
1361 static void *p_start(struct seq_file *m, loff_t *pos)
1362         __acquires(RCU)
1363 {
1364         return __start(m, pos, TRACE_PIDS);
1365 }
1366
1367 static void *np_start(struct seq_file *m, loff_t *pos)
1368         __acquires(RCU)
1369 {
1370         return __start(m, pos, TRACE_NO_PIDS);
1371 }
1372
1373 static void p_stop(struct seq_file *m, void *p)
1374         __releases(RCU)
1375 {
1376         rcu_read_unlock_sched();
1377         mutex_unlock(&event_mutex);
1378 }
1379
1380 static ssize_t
1381 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1382                   loff_t *ppos)
1383 {
1384         struct trace_event_file *file;
1385         unsigned long flags;
1386         char buf[4] = "0";
1387
1388         mutex_lock(&event_mutex);
1389         file = event_file_file(filp);
1390         if (likely(file))
1391                 flags = file->flags;
1392         mutex_unlock(&event_mutex);
1393
1394         if (!file)
1395                 return -ENODEV;
1396
1397         if (flags & EVENT_FILE_FL_ENABLED &&
1398             !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1399                 strcpy(buf, "1");
1400
1401         if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1402             flags & EVENT_FILE_FL_SOFT_MODE)
1403                 strcat(buf, "*");
1404
1405         strcat(buf, "\n");
1406
1407         return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1408 }
1409
1410 static ssize_t
1411 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1412                    loff_t *ppos)
1413 {
1414         struct trace_event_file *file;
1415         unsigned long val;
1416         int ret;
1417
1418         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1419         if (ret)
1420                 return ret;
1421
1422         switch (val) {
1423         case 0:
1424         case 1:
1425                 ret = -ENODEV;
1426                 mutex_lock(&event_mutex);
1427                 file = event_file_file(filp);
1428                 if (likely(file)) {
1429                         ret = tracing_update_buffers(file->tr);
1430                         if (ret < 0) {
1431                                 mutex_unlock(&event_mutex);
1432                                 return ret;
1433                         }
1434                         ret = ftrace_event_enable_disable(file, val);
1435                 }
1436                 mutex_unlock(&event_mutex);
1437                 break;
1438
1439         default:
1440                 return -EINVAL;
1441         }
1442
1443         *ppos += cnt;
1444
1445         return ret ? ret : cnt;
1446 }
1447
1448 static ssize_t
1449 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1450                    loff_t *ppos)
1451 {
1452         const char set_to_char[4] = { '?', '0', '1', 'X' };
1453         struct trace_subsystem_dir *dir = filp->private_data;
1454         struct event_subsystem *system = dir->subsystem;
1455         struct trace_event_call *call;
1456         struct trace_event_file *file;
1457         struct trace_array *tr = dir->tr;
1458         char buf[2];
1459         int set = 0;
1460         int ret;
1461
1462         mutex_lock(&event_mutex);
1463         list_for_each_entry(file, &tr->events, list) {
1464                 call = file->event_call;
1465                 if ((call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
1466                     !trace_event_name(call) || !call->class || !call->class->reg)
1467                         continue;
1468
1469                 if (system && strcmp(call->class->system, system->name) != 0)
1470                         continue;
1471
1472                 /*
1473                  * We need to find out if all the events are set
1474                  * or if all events or cleared, or if we have
1475                  * a mixture.
1476                  */
1477                 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1478
1479                 /*
1480                  * If we have a mixture, no need to look further.
1481                  */
1482                 if (set == 3)
1483                         break;
1484         }
1485         mutex_unlock(&event_mutex);
1486
1487         buf[0] = set_to_char[set];
1488         buf[1] = '\n';
1489
1490         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1491
1492         return ret;
1493 }
1494
1495 static ssize_t
1496 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1497                     loff_t *ppos)
1498 {
1499         struct trace_subsystem_dir *dir = filp->private_data;
1500         struct event_subsystem *system = dir->subsystem;
1501         const char *name = NULL;
1502         unsigned long val;
1503         ssize_t ret;
1504
1505         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1506         if (ret)
1507                 return ret;
1508
1509         ret = tracing_update_buffers(dir->tr);
1510         if (ret < 0)
1511                 return ret;
1512
1513         if (val != 0 && val != 1)
1514                 return -EINVAL;
1515
1516         /*
1517          * Opening of "enable" adds a ref count to system,
1518          * so the name is safe to use.
1519          */
1520         if (system)
1521                 name = system->name;
1522
1523         ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1524         if (ret)
1525                 goto out;
1526
1527         ret = cnt;
1528
1529 out:
1530         *ppos += cnt;
1531
1532         return ret;
1533 }
1534
1535 enum {
1536         FORMAT_HEADER           = 1,
1537         FORMAT_FIELD_SEPERATOR  = 2,
1538         FORMAT_PRINTFMT         = 3,
1539 };
1540
1541 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1542 {
1543         struct trace_event_file *file = event_file_data(m->private);
1544         struct trace_event_call *call = file->event_call;
1545         struct list_head *common_head = &ftrace_common_fields;
1546         struct list_head *head = trace_get_fields(call);
1547         struct list_head *node = v;
1548
1549         (*pos)++;
1550
1551         switch ((unsigned long)v) {
1552         case FORMAT_HEADER:
1553                 node = common_head;
1554                 break;
1555
1556         case FORMAT_FIELD_SEPERATOR:
1557                 node = head;
1558                 break;
1559
1560         case FORMAT_PRINTFMT:
1561                 /* all done */
1562                 return NULL;
1563         }
1564
1565         node = node->prev;
1566         if (node == common_head)
1567                 return (void *)FORMAT_FIELD_SEPERATOR;
1568         else if (node == head)
1569                 return (void *)FORMAT_PRINTFMT;
1570         else
1571                 return node;
1572 }
1573
1574 static int f_show(struct seq_file *m, void *v)
1575 {
1576         struct trace_event_file *file = event_file_data(m->private);
1577         struct trace_event_call *call = file->event_call;
1578         struct ftrace_event_field *field;
1579         const char *array_descriptor;
1580
1581         switch ((unsigned long)v) {
1582         case FORMAT_HEADER:
1583                 seq_printf(m, "name: %s\n", trace_event_name(call));
1584                 seq_printf(m, "ID: %d\n", call->event.type);
1585                 seq_puts(m, "format:\n");
1586                 return 0;
1587
1588         case FORMAT_FIELD_SEPERATOR:
1589                 seq_putc(m, '\n');
1590                 return 0;
1591
1592         case FORMAT_PRINTFMT:
1593                 seq_printf(m, "\nprint fmt: %s\n",
1594                            call->print_fmt);
1595                 return 0;
1596         }
1597
1598         field = list_entry(v, struct ftrace_event_field, link);
1599         /*
1600          * Smartly shows the array type(except dynamic array).
1601          * Normal:
1602          *      field:TYPE VAR
1603          * If TYPE := TYPE[LEN], it is shown:
1604          *      field:TYPE VAR[LEN]
1605          */
1606         array_descriptor = strchr(field->type, '[');
1607
1608         if (str_has_prefix(field->type, "__data_loc"))
1609                 array_descriptor = NULL;
1610
1611         if (!array_descriptor)
1612                 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1613                            field->type, field->name, field->offset,
1614                            field->size, !!field->is_signed);
1615         else if (field->len)
1616                 seq_printf(m, "\tfield:%.*s %s[%d];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1617                            (int)(array_descriptor - field->type),
1618                            field->type, field->name,
1619                            field->len, field->offset,
1620                            field->size, !!field->is_signed);
1621         else
1622                 seq_printf(m, "\tfield:%.*s %s[];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1623                                 (int)(array_descriptor - field->type),
1624                                 field->type, field->name,
1625                                 field->offset, field->size, !!field->is_signed);
1626
1627         return 0;
1628 }
1629
1630 static void *f_start(struct seq_file *m, loff_t *pos)
1631 {
1632         struct trace_event_file *file;
1633         void *p = (void *)FORMAT_HEADER;
1634         loff_t l = 0;
1635
1636         /* ->stop() is called even if ->start() fails */
1637         mutex_lock(&event_mutex);
1638         file = event_file_file(m->private);
1639         if (!file)
1640                 return ERR_PTR(-ENODEV);
1641
1642         while (l < *pos && p)
1643                 p = f_next(m, p, &l);
1644
1645         return p;
1646 }
1647
1648 static void f_stop(struct seq_file *m, void *p)
1649 {
1650         mutex_unlock(&event_mutex);
1651 }
1652
1653 static const struct seq_operations trace_format_seq_ops = {
1654         .start          = f_start,
1655         .next           = f_next,
1656         .stop           = f_stop,
1657         .show           = f_show,
1658 };
1659
1660 static int trace_format_open(struct inode *inode, struct file *file)
1661 {
1662         struct seq_file *m;
1663         int ret;
1664
1665         /* Do we want to hide event format files on tracefs lockdown? */
1666
1667         ret = seq_open(file, &trace_format_seq_ops);
1668         if (ret < 0)
1669                 return ret;
1670
1671         m = file->private_data;
1672         m->private = file;
1673
1674         return 0;
1675 }
1676
1677 #ifdef CONFIG_PERF_EVENTS
1678 static ssize_t
1679 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1680 {
1681         int id = (long)event_file_data(filp);
1682         char buf[32];
1683         int len;
1684
1685         if (unlikely(!id))
1686                 return -ENODEV;
1687
1688         len = sprintf(buf, "%d\n", id);
1689
1690         return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1691 }
1692 #endif
1693
1694 static ssize_t
1695 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1696                   loff_t *ppos)
1697 {
1698         struct trace_event_file *file;
1699         struct trace_seq *s;
1700         int r = -ENODEV;
1701
1702         if (*ppos)
1703                 return 0;
1704
1705         s = kmalloc(sizeof(*s), GFP_KERNEL);
1706
1707         if (!s)
1708                 return -ENOMEM;
1709
1710         trace_seq_init(s);
1711
1712         mutex_lock(&event_mutex);
1713         file = event_file_file(filp);
1714         if (file)
1715                 print_event_filter(file, s);
1716         mutex_unlock(&event_mutex);
1717
1718         if (file)
1719                 r = simple_read_from_buffer(ubuf, cnt, ppos,
1720                                             s->buffer, trace_seq_used(s));
1721
1722         kfree(s);
1723
1724         return r;
1725 }
1726
1727 static ssize_t
1728 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1729                    loff_t *ppos)
1730 {
1731         struct trace_event_file *file;
1732         char *buf;
1733         int err = -ENODEV;
1734
1735         if (cnt >= PAGE_SIZE)
1736                 return -EINVAL;
1737
1738         buf = memdup_user_nul(ubuf, cnt);
1739         if (IS_ERR(buf))
1740                 return PTR_ERR(buf);
1741
1742         mutex_lock(&event_mutex);
1743         file = event_file_file(filp);
1744         if (file) {
1745                 if (file->flags & EVENT_FILE_FL_FREED)
1746                         err = -ENODEV;
1747                 else
1748                         err = apply_event_filter(file, buf);
1749         }
1750         mutex_unlock(&event_mutex);
1751
1752         kfree(buf);
1753         if (err < 0)
1754                 return err;
1755
1756         *ppos += cnt;
1757
1758         return cnt;
1759 }
1760
1761 static LIST_HEAD(event_subsystems);
1762
1763 static int subsystem_open(struct inode *inode, struct file *filp)
1764 {
1765         struct trace_subsystem_dir *dir = NULL, *iter_dir;
1766         struct trace_array *tr = NULL, *iter_tr;
1767         struct event_subsystem *system = NULL;
1768         int ret;
1769
1770         if (tracing_is_disabled())
1771                 return -ENODEV;
1772
1773         /* Make sure the system still exists */
1774         mutex_lock(&event_mutex);
1775         mutex_lock(&trace_types_lock);
1776         list_for_each_entry(iter_tr, &ftrace_trace_arrays, list) {
1777                 list_for_each_entry(iter_dir, &iter_tr->systems, list) {
1778                         if (iter_dir == inode->i_private) {
1779                                 /* Don't open systems with no events */
1780                                 tr = iter_tr;
1781                                 dir = iter_dir;
1782                                 if (dir->nr_events) {
1783                                         __get_system_dir(dir);
1784                                         system = dir->subsystem;
1785                                 }
1786                                 goto exit_loop;
1787                         }
1788                 }
1789         }
1790  exit_loop:
1791         mutex_unlock(&trace_types_lock);
1792         mutex_unlock(&event_mutex);
1793
1794         if (!system)
1795                 return -ENODEV;
1796
1797         /* Still need to increment the ref count of the system */
1798         if (trace_array_get(tr) < 0) {
1799                 put_system(dir);
1800                 return -ENODEV;
1801         }
1802
1803         ret = tracing_open_generic(inode, filp);
1804         if (ret < 0) {
1805                 trace_array_put(tr);
1806                 put_system(dir);
1807         }
1808
1809         return ret;
1810 }
1811
1812 static int system_tr_open(struct inode *inode, struct file *filp)
1813 {
1814         struct trace_subsystem_dir *dir;
1815         struct trace_array *tr = inode->i_private;
1816         int ret;
1817
1818         /* Make a temporary dir that has no system but points to tr */
1819         dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1820         if (!dir)
1821                 return -ENOMEM;
1822
1823         ret = tracing_open_generic_tr(inode, filp);
1824         if (ret < 0) {
1825                 kfree(dir);
1826                 return ret;
1827         }
1828         dir->tr = tr;
1829         filp->private_data = dir;
1830
1831         return 0;
1832 }
1833
1834 static int subsystem_release(struct inode *inode, struct file *file)
1835 {
1836         struct trace_subsystem_dir *dir = file->private_data;
1837
1838         trace_array_put(dir->tr);
1839
1840         /*
1841          * If dir->subsystem is NULL, then this is a temporary
1842          * descriptor that was made for a trace_array to enable
1843          * all subsystems.
1844          */
1845         if (dir->subsystem)
1846                 put_system(dir);
1847         else
1848                 kfree(dir);
1849
1850         return 0;
1851 }
1852
1853 static ssize_t
1854 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1855                       loff_t *ppos)
1856 {
1857         struct trace_subsystem_dir *dir = filp->private_data;
1858         struct event_subsystem *system = dir->subsystem;
1859         struct trace_seq *s;
1860         int r;
1861
1862         if (*ppos)
1863                 return 0;
1864
1865         s = kmalloc(sizeof(*s), GFP_KERNEL);
1866         if (!s)
1867                 return -ENOMEM;
1868
1869         trace_seq_init(s);
1870
1871         print_subsystem_event_filter(system, s);
1872         r = simple_read_from_buffer(ubuf, cnt, ppos,
1873                                     s->buffer, trace_seq_used(s));
1874
1875         kfree(s);
1876
1877         return r;
1878 }
1879
1880 static ssize_t
1881 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1882                        loff_t *ppos)
1883 {
1884         struct trace_subsystem_dir *dir = filp->private_data;
1885         char *buf;
1886         int err;
1887
1888         if (cnt >= PAGE_SIZE)
1889                 return -EINVAL;
1890
1891         buf = memdup_user_nul(ubuf, cnt);
1892         if (IS_ERR(buf))
1893                 return PTR_ERR(buf);
1894
1895         err = apply_subsystem_event_filter(dir, buf);
1896         kfree(buf);
1897         if (err < 0)
1898                 return err;
1899
1900         *ppos += cnt;
1901
1902         return cnt;
1903 }
1904
1905 static ssize_t
1906 show_header_page_file(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1907 {
1908         struct trace_array *tr = filp->private_data;
1909         struct trace_seq *s;
1910         int r;
1911
1912         if (*ppos)
1913                 return 0;
1914
1915         s = kmalloc(sizeof(*s), GFP_KERNEL);
1916         if (!s)
1917                 return -ENOMEM;
1918
1919         trace_seq_init(s);
1920
1921         ring_buffer_print_page_header(tr->array_buffer.buffer, s);
1922         r = simple_read_from_buffer(ubuf, cnt, ppos,
1923                                     s->buffer, trace_seq_used(s));
1924
1925         kfree(s);
1926
1927         return r;
1928 }
1929
1930 static ssize_t
1931 show_header_event_file(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1932 {
1933         struct trace_seq *s;
1934         int r;
1935
1936         if (*ppos)
1937                 return 0;
1938
1939         s = kmalloc(sizeof(*s), GFP_KERNEL);
1940         if (!s)
1941                 return -ENOMEM;
1942
1943         trace_seq_init(s);
1944
1945         ring_buffer_print_entry_header(s);
1946         r = simple_read_from_buffer(ubuf, cnt, ppos,
1947                                     s->buffer, trace_seq_used(s));
1948
1949         kfree(s);
1950
1951         return r;
1952 }
1953
1954 static void ignore_task_cpu(void *data)
1955 {
1956         struct trace_array *tr = data;
1957         struct trace_pid_list *pid_list;
1958         struct trace_pid_list *no_pid_list;
1959
1960         /*
1961          * This function is called by on_each_cpu() while the
1962          * event_mutex is held.
1963          */
1964         pid_list = rcu_dereference_protected(tr->filtered_pids,
1965                                              mutex_is_locked(&event_mutex));
1966         no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
1967                                              mutex_is_locked(&event_mutex));
1968
1969         this_cpu_write(tr->array_buffer.data->ignore_pid,
1970                        trace_ignore_this_task(pid_list, no_pid_list, current));
1971 }
1972
1973 static void register_pid_events(struct trace_array *tr)
1974 {
1975         /*
1976          * Register a probe that is called before all other probes
1977          * to set ignore_pid if next or prev do not match.
1978          * Register a probe this is called after all other probes
1979          * to only keep ignore_pid set if next pid matches.
1980          */
1981         register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1982                                          tr, INT_MAX);
1983         register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1984                                          tr, 0);
1985
1986         register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1987                                          tr, INT_MAX);
1988         register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1989                                          tr, 0);
1990
1991         register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1992                                              tr, INT_MAX);
1993         register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1994                                              tr, 0);
1995
1996         register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1997                                          tr, INT_MAX);
1998         register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1999                                          tr, 0);
2000 }
2001
2002 static ssize_t
2003 event_pid_write(struct file *filp, const char __user *ubuf,
2004                 size_t cnt, loff_t *ppos, int type)
2005 {
2006         struct seq_file *m = filp->private_data;
2007         struct trace_array *tr = m->private;
2008         struct trace_pid_list *filtered_pids = NULL;
2009         struct trace_pid_list *other_pids = NULL;
2010         struct trace_pid_list *pid_list;
2011         struct trace_event_file *file;
2012         ssize_t ret;
2013
2014         if (!cnt)
2015                 return 0;
2016
2017         ret = tracing_update_buffers(tr);
2018         if (ret < 0)
2019                 return ret;
2020
2021         mutex_lock(&event_mutex);
2022
2023         if (type == TRACE_PIDS) {
2024                 filtered_pids = rcu_dereference_protected(tr->filtered_pids,
2025                                                           lockdep_is_held(&event_mutex));
2026                 other_pids = rcu_dereference_protected(tr->filtered_no_pids,
2027                                                           lockdep_is_held(&event_mutex));
2028         } else {
2029                 filtered_pids = rcu_dereference_protected(tr->filtered_no_pids,
2030                                                           lockdep_is_held(&event_mutex));
2031                 other_pids = rcu_dereference_protected(tr->filtered_pids,
2032                                                           lockdep_is_held(&event_mutex));
2033         }
2034
2035         ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
2036         if (ret < 0)
2037                 goto out;
2038
2039         if (type == TRACE_PIDS)
2040                 rcu_assign_pointer(tr->filtered_pids, pid_list);
2041         else
2042                 rcu_assign_pointer(tr->filtered_no_pids, pid_list);
2043
2044         list_for_each_entry(file, &tr->events, list) {
2045                 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
2046         }
2047
2048         if (filtered_pids) {
2049                 tracepoint_synchronize_unregister();
2050                 trace_pid_list_free(filtered_pids);
2051         } else if (pid_list && !other_pids) {
2052                 register_pid_events(tr);
2053         }
2054
2055         /*
2056          * Ignoring of pids is done at task switch. But we have to
2057          * check for those tasks that are currently running.
2058          * Always do this in case a pid was appended or removed.
2059          */
2060         on_each_cpu(ignore_task_cpu, tr, 1);
2061
2062  out:
2063         mutex_unlock(&event_mutex);
2064
2065         if (ret > 0)
2066                 *ppos += ret;
2067
2068         return ret;
2069 }
2070
2071 static ssize_t
2072 ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
2073                        size_t cnt, loff_t *ppos)
2074 {
2075         return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
2076 }
2077
2078 static ssize_t
2079 ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
2080                         size_t cnt, loff_t *ppos)
2081 {
2082         return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
2083 }
2084
2085 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
2086 static int ftrace_event_set_open(struct inode *inode, struct file *file);
2087 static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
2088 static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
2089 static int ftrace_event_release(struct inode *inode, struct file *file);
2090
2091 static const struct seq_operations show_event_seq_ops = {
2092         .start = t_start,
2093         .next = t_next,
2094         .show = t_show,
2095         .stop = t_stop,
2096 };
2097
2098 static const struct seq_operations show_set_event_seq_ops = {
2099         .start = s_start,
2100         .next = s_next,
2101         .show = t_show,
2102         .stop = t_stop,
2103 };
2104
2105 static const struct seq_operations show_set_pid_seq_ops = {
2106         .start = p_start,
2107         .next = p_next,
2108         .show = trace_pid_show,
2109         .stop = p_stop,
2110 };
2111
2112 static const struct seq_operations show_set_no_pid_seq_ops = {
2113         .start = np_start,
2114         .next = np_next,
2115         .show = trace_pid_show,
2116         .stop = p_stop,
2117 };
2118
2119 static const struct file_operations ftrace_avail_fops = {
2120         .open = ftrace_event_avail_open,
2121         .read = seq_read,
2122         .llseek = seq_lseek,
2123         .release = seq_release,
2124 };
2125
2126 static const struct file_operations ftrace_set_event_fops = {
2127         .open = ftrace_event_set_open,
2128         .read = seq_read,
2129         .write = ftrace_event_write,
2130         .llseek = seq_lseek,
2131         .release = ftrace_event_release,
2132 };
2133
2134 static const struct file_operations ftrace_set_event_pid_fops = {
2135         .open = ftrace_event_set_pid_open,
2136         .read = seq_read,
2137         .write = ftrace_event_pid_write,
2138         .llseek = seq_lseek,
2139         .release = ftrace_event_release,
2140 };
2141
2142 static const struct file_operations ftrace_set_event_notrace_pid_fops = {
2143         .open = ftrace_event_set_npid_open,
2144         .read = seq_read,
2145         .write = ftrace_event_npid_write,
2146         .llseek = seq_lseek,
2147         .release = ftrace_event_release,
2148 };
2149
2150 static const struct file_operations ftrace_enable_fops = {
2151         .open = tracing_open_file_tr,
2152         .read = event_enable_read,
2153         .write = event_enable_write,
2154         .release = tracing_release_file_tr,
2155         .llseek = default_llseek,
2156 };
2157
2158 static const struct file_operations ftrace_event_format_fops = {
2159         .open = trace_format_open,
2160         .read = seq_read,
2161         .llseek = seq_lseek,
2162         .release = seq_release,
2163 };
2164
2165 #ifdef CONFIG_PERF_EVENTS
2166 static const struct file_operations ftrace_event_id_fops = {
2167         .read = event_id_read,
2168         .llseek = default_llseek,
2169 };
2170 #endif
2171
2172 static const struct file_operations ftrace_event_filter_fops = {
2173         .open = tracing_open_file_tr,
2174         .read = event_filter_read,
2175         .write = event_filter_write,
2176         .release = tracing_release_file_tr,
2177         .llseek = default_llseek,
2178 };
2179
2180 static const struct file_operations ftrace_subsystem_filter_fops = {
2181         .open = subsystem_open,
2182         .read = subsystem_filter_read,
2183         .write = subsystem_filter_write,
2184         .llseek = default_llseek,
2185         .release = subsystem_release,
2186 };
2187
2188 static const struct file_operations ftrace_system_enable_fops = {
2189         .open = subsystem_open,
2190         .read = system_enable_read,
2191         .write = system_enable_write,
2192         .llseek = default_llseek,
2193         .release = subsystem_release,
2194 };
2195
2196 static const struct file_operations ftrace_tr_enable_fops = {
2197         .open = system_tr_open,
2198         .read = system_enable_read,
2199         .write = system_enable_write,
2200         .llseek = default_llseek,
2201         .release = subsystem_release,
2202 };
2203
2204 static const struct file_operations ftrace_show_header_page_fops = {
2205         .open = tracing_open_generic_tr,
2206         .read = show_header_page_file,
2207         .llseek = default_llseek,
2208         .release = tracing_release_generic_tr,
2209 };
2210
2211 static const struct file_operations ftrace_show_header_event_fops = {
2212         .open = tracing_open_generic_tr,
2213         .read = show_header_event_file,
2214         .llseek = default_llseek,
2215         .release = tracing_release_generic_tr,
2216 };
2217
2218 static int
2219 ftrace_event_open(struct inode *inode, struct file *file,
2220                   const struct seq_operations *seq_ops)
2221 {
2222         struct seq_file *m;
2223         int ret;
2224
2225         ret = security_locked_down(LOCKDOWN_TRACEFS);
2226         if (ret)
2227                 return ret;
2228
2229         ret = seq_open(file, seq_ops);
2230         if (ret < 0)
2231                 return ret;
2232         m = file->private_data;
2233         /* copy tr over to seq ops */
2234         m->private = inode->i_private;
2235
2236         return ret;
2237 }
2238
2239 static int ftrace_event_release(struct inode *inode, struct file *file)
2240 {
2241         struct trace_array *tr = inode->i_private;
2242
2243         trace_array_put(tr);
2244
2245         return seq_release(inode, file);
2246 }
2247
2248 static int
2249 ftrace_event_avail_open(struct inode *inode, struct file *file)
2250 {
2251         const struct seq_operations *seq_ops = &show_event_seq_ops;
2252
2253         /* Checks for tracefs lockdown */
2254         return ftrace_event_open(inode, file, seq_ops);
2255 }
2256
2257 static int
2258 ftrace_event_set_open(struct inode *inode, struct file *file)
2259 {
2260         const struct seq_operations *seq_ops = &show_set_event_seq_ops;
2261         struct trace_array *tr = inode->i_private;
2262         int ret;
2263
2264         ret = tracing_check_open_get_tr(tr);
2265         if (ret)
2266                 return ret;
2267
2268         if ((file->f_mode & FMODE_WRITE) &&
2269             (file->f_flags & O_TRUNC))
2270                 ftrace_clear_events(tr);
2271
2272         ret = ftrace_event_open(inode, file, seq_ops);
2273         if (ret < 0)
2274                 trace_array_put(tr);
2275         return ret;
2276 }
2277
2278 static int
2279 ftrace_event_set_pid_open(struct inode *inode, struct file *file)
2280 {
2281         const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
2282         struct trace_array *tr = inode->i_private;
2283         int ret;
2284
2285         ret = tracing_check_open_get_tr(tr);
2286         if (ret)
2287                 return ret;
2288
2289         if ((file->f_mode & FMODE_WRITE) &&
2290             (file->f_flags & O_TRUNC))
2291                 ftrace_clear_event_pids(tr, TRACE_PIDS);
2292
2293         ret = ftrace_event_open(inode, file, seq_ops);
2294         if (ret < 0)
2295                 trace_array_put(tr);
2296         return ret;
2297 }
2298
2299 static int
2300 ftrace_event_set_npid_open(struct inode *inode, struct file *file)
2301 {
2302         const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops;
2303         struct trace_array *tr = inode->i_private;
2304         int ret;
2305
2306         ret = tracing_check_open_get_tr(tr);
2307         if (ret)
2308                 return ret;
2309
2310         if ((file->f_mode & FMODE_WRITE) &&
2311             (file->f_flags & O_TRUNC))
2312                 ftrace_clear_event_pids(tr, TRACE_NO_PIDS);
2313
2314         ret = ftrace_event_open(inode, file, seq_ops);
2315         if (ret < 0)
2316                 trace_array_put(tr);
2317         return ret;
2318 }
2319
2320 static struct event_subsystem *
2321 create_new_subsystem(const char *name)
2322 {
2323         struct event_subsystem *system;
2324
2325         /* need to create new entry */
2326         system = kmalloc(sizeof(*system), GFP_KERNEL);
2327         if (!system)
2328                 return NULL;
2329
2330         system->ref_count = 1;
2331
2332         /* Only allocate if dynamic (kprobes and modules) */
2333         system->name = kstrdup_const(name, GFP_KERNEL);
2334         if (!system->name)
2335                 goto out_free;
2336
2337         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
2338         if (!system->filter)
2339                 goto out_free;
2340
2341         list_add(&system->list, &event_subsystems);
2342
2343         return system;
2344
2345  out_free:
2346         kfree_const(system->name);
2347         kfree(system);
2348         return NULL;
2349 }
2350
2351 static int system_callback(const char *name, umode_t *mode, void **data,
2352                     const struct file_operations **fops)
2353 {
2354         if (strcmp(name, "filter") == 0)
2355                 *fops = &ftrace_subsystem_filter_fops;
2356
2357         else if (strcmp(name, "enable") == 0)
2358                 *fops = &ftrace_system_enable_fops;
2359
2360         else
2361                 return 0;
2362
2363         *mode = TRACE_MODE_WRITE;
2364         return 1;
2365 }
2366
2367 static struct eventfs_inode *
2368 event_subsystem_dir(struct trace_array *tr, const char *name,
2369                     struct trace_event_file *file, struct eventfs_inode *parent)
2370 {
2371         struct event_subsystem *system, *iter;
2372         struct trace_subsystem_dir *dir;
2373         struct eventfs_inode *ei;
2374         int nr_entries;
2375         static struct eventfs_entry system_entries[] = {
2376                 {
2377                         .name           = "filter",
2378                         .callback       = system_callback,
2379                 },
2380                 {
2381                         .name           = "enable",
2382                         .callback       = system_callback,
2383                 }
2384         };
2385
2386         /* First see if we did not already create this dir */
2387         list_for_each_entry(dir, &tr->systems, list) {
2388                 system = dir->subsystem;
2389                 if (strcmp(system->name, name) == 0) {
2390                         dir->nr_events++;
2391                         file->system = dir;
2392                         return dir->ei;
2393                 }
2394         }
2395
2396         /* Now see if the system itself exists. */
2397         system = NULL;
2398         list_for_each_entry(iter, &event_subsystems, list) {
2399                 if (strcmp(iter->name, name) == 0) {
2400                         system = iter;
2401                         break;
2402                 }
2403         }
2404
2405         dir = kmalloc(sizeof(*dir), GFP_KERNEL);
2406         if (!dir)
2407                 goto out_fail;
2408
2409         if (!system) {
2410                 system = create_new_subsystem(name);
2411                 if (!system)
2412                         goto out_free;
2413         } else
2414                 __get_system(system);
2415
2416         /* ftrace only has directories no files */
2417         if (strcmp(name, "ftrace") == 0)
2418                 nr_entries = 0;
2419         else
2420                 nr_entries = ARRAY_SIZE(system_entries);
2421
2422         ei = eventfs_create_dir(name, parent, system_entries, nr_entries, dir);
2423         if (IS_ERR(ei)) {
2424                 pr_warn("Failed to create system directory %s\n", name);
2425                 __put_system(system);
2426                 goto out_free;
2427         }
2428
2429         dir->ei = ei;
2430         dir->tr = tr;
2431         dir->ref_count = 1;
2432         dir->nr_events = 1;
2433         dir->subsystem = system;
2434         file->system = dir;
2435
2436         list_add(&dir->list, &tr->systems);
2437
2438         return dir->ei;
2439
2440  out_free:
2441         kfree(dir);
2442  out_fail:
2443         /* Only print this message if failed on memory allocation */
2444         if (!dir || !system)
2445                 pr_warn("No memory to create event subsystem %s\n", name);
2446         return NULL;
2447 }
2448
2449 static int
2450 event_define_fields(struct trace_event_call *call)
2451 {
2452         struct list_head *head;
2453         int ret = 0;
2454
2455         /*
2456          * Other events may have the same class. Only update
2457          * the fields if they are not already defined.
2458          */
2459         head = trace_get_fields(call);
2460         if (list_empty(head)) {
2461                 struct trace_event_fields *field = call->class->fields_array;
2462                 unsigned int offset = sizeof(struct trace_entry);
2463
2464                 for (; field->type; field++) {
2465                         if (field->type == TRACE_FUNCTION_TYPE) {
2466                                 field->define_fields(call);
2467                                 break;
2468                         }
2469
2470                         offset = ALIGN(offset, field->align);
2471                         ret = trace_define_field_ext(call, field->type, field->name,
2472                                                  offset, field->size,
2473                                                  field->is_signed, field->filter_type,
2474                                                  field->len);
2475                         if (WARN_ON_ONCE(ret)) {
2476                                 pr_err("error code is %d\n", ret);
2477                                 break;
2478                         }
2479
2480                         offset += field->size;
2481                 }
2482         }
2483
2484         return ret;
2485 }
2486
2487 static int event_callback(const char *name, umode_t *mode, void **data,
2488                           const struct file_operations **fops)
2489 {
2490         struct trace_event_file *file = *data;
2491         struct trace_event_call *call = file->event_call;
2492
2493         if (strcmp(name, "format") == 0) {
2494                 *mode = TRACE_MODE_READ;
2495                 *fops = &ftrace_event_format_fops;
2496                 return 1;
2497         }
2498
2499         /*
2500          * Only event directories that can be enabled should have
2501          * triggers or filters, with the exception of the "print"
2502          * event that can have a "trigger" file.
2503          */
2504         if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
2505                 if (call->class->reg && strcmp(name, "enable") == 0) {
2506                         *mode = TRACE_MODE_WRITE;
2507                         *fops = &ftrace_enable_fops;
2508                         return 1;
2509                 }
2510
2511                 if (strcmp(name, "filter") == 0) {
2512                         *mode = TRACE_MODE_WRITE;
2513                         *fops = &ftrace_event_filter_fops;
2514                         return 1;
2515                 }
2516         }
2517
2518         if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
2519             strcmp(trace_event_name(call), "print") == 0) {
2520                 if (strcmp(name, "trigger") == 0) {
2521                         *mode = TRACE_MODE_WRITE;
2522                         *fops = &event_trigger_fops;
2523                         return 1;
2524                 }
2525         }
2526
2527 #ifdef CONFIG_PERF_EVENTS
2528         if (call->event.type && call->class->reg &&
2529             strcmp(name, "id") == 0) {
2530                 *mode = TRACE_MODE_READ;
2531                 *data = (void *)(long)call->event.type;
2532                 *fops = &ftrace_event_id_fops;
2533                 return 1;
2534         }
2535 #endif
2536
2537 #ifdef CONFIG_HIST_TRIGGERS
2538         if (strcmp(name, "hist") == 0) {
2539                 *mode = TRACE_MODE_READ;
2540                 *fops = &event_hist_fops;
2541                 return 1;
2542         }
2543 #endif
2544 #ifdef CONFIG_HIST_TRIGGERS_DEBUG
2545         if (strcmp(name, "hist_debug") == 0) {
2546                 *mode = TRACE_MODE_READ;
2547                 *fops = &event_hist_debug_fops;
2548                 return 1;
2549         }
2550 #endif
2551 #ifdef CONFIG_TRACE_EVENT_INJECT
2552         if (call->event.type && call->class->reg &&
2553             strcmp(name, "inject") == 0) {
2554                 *mode = 0200;
2555                 *fops = &event_inject_fops;
2556                 return 1;
2557         }
2558 #endif
2559         return 0;
2560 }
2561
2562 /* The file is incremented on creation and freeing the enable file decrements it */
2563 static void event_release(const char *name, void *data)
2564 {
2565         struct trace_event_file *file = data;
2566
2567         event_file_put(file);
2568 }
2569
2570 static int
2571 event_create_dir(struct eventfs_inode *parent, struct trace_event_file *file)
2572 {
2573         struct trace_event_call *call = file->event_call;
2574         struct trace_array *tr = file->tr;
2575         struct eventfs_inode *e_events;
2576         struct eventfs_inode *ei;
2577         const char *name;
2578         int nr_entries;
2579         int ret;
2580         static struct eventfs_entry event_entries[] = {
2581                 {
2582                         .name           = "enable",
2583                         .callback       = event_callback,
2584                         .release        = event_release,
2585                 },
2586                 {
2587                         .name           = "filter",
2588                         .callback       = event_callback,
2589                 },
2590                 {
2591                         .name           = "trigger",
2592                         .callback       = event_callback,
2593                 },
2594                 {
2595                         .name           = "format",
2596                         .callback       = event_callback,
2597                 },
2598 #ifdef CONFIG_PERF_EVENTS
2599                 {
2600                         .name           = "id",
2601                         .callback       = event_callback,
2602                 },
2603 #endif
2604 #ifdef CONFIG_HIST_TRIGGERS
2605                 {
2606                         .name           = "hist",
2607                         .callback       = event_callback,
2608                 },
2609 #endif
2610 #ifdef CONFIG_HIST_TRIGGERS_DEBUG
2611                 {
2612                         .name           = "hist_debug",
2613                         .callback       = event_callback,
2614                 },
2615 #endif
2616 #ifdef CONFIG_TRACE_EVENT_INJECT
2617                 {
2618                         .name           = "inject",
2619                         .callback       = event_callback,
2620                 },
2621 #endif
2622         };
2623
2624         /*
2625          * If the trace point header did not define TRACE_SYSTEM
2626          * then the system would be called "TRACE_SYSTEM". This should
2627          * never happen.
2628          */
2629         if (WARN_ON_ONCE(strcmp(call->class->system, TRACE_SYSTEM) == 0))
2630                 return -ENODEV;
2631
2632         e_events = event_subsystem_dir(tr, call->class->system, file, parent);
2633         if (!e_events)
2634                 return -ENOMEM;
2635
2636         nr_entries = ARRAY_SIZE(event_entries);
2637
2638         name = trace_event_name(call);
2639         ei = eventfs_create_dir(name, e_events, event_entries, nr_entries, file);
2640         if (IS_ERR(ei)) {
2641                 pr_warn("Could not create tracefs '%s' directory\n", name);
2642                 return -1;
2643         }
2644
2645         file->ei = ei;
2646
2647         ret = event_define_fields(call);
2648         if (ret < 0) {
2649                 pr_warn("Could not initialize trace point events/%s\n", name);
2650                 return ret;
2651         }
2652
2653         /* Gets decremented on freeing of the "enable" file */
2654         event_file_get(file);
2655
2656         return 0;
2657 }
2658
2659 static void remove_event_from_tracers(struct trace_event_call *call)
2660 {
2661         struct trace_event_file *file;
2662         struct trace_array *tr;
2663
2664         do_for_each_event_file_safe(tr, file) {
2665                 if (file->event_call != call)
2666                         continue;
2667
2668                 remove_event_file_dir(file);
2669                 /*
2670                  * The do_for_each_event_file_safe() is
2671                  * a double loop. After finding the call for this
2672                  * trace_array, we use break to jump to the next
2673                  * trace_array.
2674                  */
2675                 break;
2676         } while_for_each_event_file();
2677 }
2678
2679 static void event_remove(struct trace_event_call *call)
2680 {
2681         struct trace_array *tr;
2682         struct trace_event_file *file;
2683
2684         do_for_each_event_file(tr, file) {
2685                 if (file->event_call != call)
2686                         continue;
2687
2688                 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2689                         tr->clear_trace = true;
2690
2691                 ftrace_event_enable_disable(file, 0);
2692                 /*
2693                  * The do_for_each_event_file() is
2694                  * a double loop. After finding the call for this
2695                  * trace_array, we use break to jump to the next
2696                  * trace_array.
2697                  */
2698                 break;
2699         } while_for_each_event_file();
2700
2701         if (call->event.funcs)
2702                 __unregister_trace_event(&call->event);
2703         remove_event_from_tracers(call);
2704         list_del(&call->list);
2705 }
2706
2707 static int event_init(struct trace_event_call *call)
2708 {
2709         int ret = 0;
2710         const char *name;
2711
2712         name = trace_event_name(call);
2713         if (WARN_ON(!name))
2714                 return -EINVAL;
2715
2716         if (call->class->raw_init) {
2717                 ret = call->class->raw_init(call);
2718                 if (ret < 0 && ret != -ENOSYS)
2719                         pr_warn("Could not initialize trace events/%s\n", name);
2720         }
2721
2722         return ret;
2723 }
2724
2725 static int
2726 __register_event(struct trace_event_call *call, struct module *mod)
2727 {
2728         int ret;
2729
2730         ret = event_init(call);
2731         if (ret < 0)
2732                 return ret;
2733
2734         list_add(&call->list, &ftrace_events);
2735         if (call->flags & TRACE_EVENT_FL_DYNAMIC)
2736                 atomic_set(&call->refcnt, 0);
2737         else
2738                 call->module = mod;
2739
2740         return 0;
2741 }
2742
2743 static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2744 {
2745         int rlen;
2746         int elen;
2747
2748         /* Find the length of the eval value as a string */
2749         elen = snprintf(ptr, 0, "%ld", map->eval_value);
2750         /* Make sure there's enough room to replace the string with the value */
2751         if (len < elen)
2752                 return NULL;
2753
2754         snprintf(ptr, elen + 1, "%ld", map->eval_value);
2755
2756         /* Get the rest of the string of ptr */
2757         rlen = strlen(ptr + len);
2758         memmove(ptr + elen, ptr + len, rlen);
2759         /* Make sure we end the new string */
2760         ptr[elen + rlen] = 0;
2761
2762         return ptr + elen;
2763 }
2764
2765 static void update_event_printk(struct trace_event_call *call,
2766                                 struct trace_eval_map *map)
2767 {
2768         char *ptr;
2769         int quote = 0;
2770         int len = strlen(map->eval_string);
2771
2772         for (ptr = call->print_fmt; *ptr; ptr++) {
2773                 if (*ptr == '\\') {
2774                         ptr++;
2775                         /* paranoid */
2776                         if (!*ptr)
2777                                 break;
2778                         continue;
2779                 }
2780                 if (*ptr == '"') {
2781                         quote ^= 1;
2782                         continue;
2783                 }
2784                 if (quote)
2785                         continue;
2786                 if (isdigit(*ptr)) {
2787                         /* skip numbers */
2788                         do {
2789                                 ptr++;
2790                                 /* Check for alpha chars like ULL */
2791                         } while (isalnum(*ptr));
2792                         if (!*ptr)
2793                                 break;
2794                         /*
2795                          * A number must have some kind of delimiter after
2796                          * it, and we can ignore that too.
2797                          */
2798                         continue;
2799                 }
2800                 if (isalpha(*ptr) || *ptr == '_') {
2801                         if (strncmp(map->eval_string, ptr, len) == 0 &&
2802                             !isalnum(ptr[len]) && ptr[len] != '_') {
2803                                 ptr = eval_replace(ptr, map, len);
2804                                 /* enum/sizeof string smaller than value */
2805                                 if (WARN_ON_ONCE(!ptr))
2806                                         return;
2807                                 /*
2808                                  * No need to decrement here, as eval_replace()
2809                                  * returns the pointer to the character passed
2810                                  * the eval, and two evals can not be placed
2811                                  * back to back without something in between.
2812                                  * We can skip that something in between.
2813                                  */
2814                                 continue;
2815                         }
2816                 skip_more:
2817                         do {
2818                                 ptr++;
2819                         } while (isalnum(*ptr) || *ptr == '_');
2820                         if (!*ptr)
2821                                 break;
2822                         /*
2823                          * If what comes after this variable is a '.' or
2824                          * '->' then we can continue to ignore that string.
2825                          */
2826                         if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2827                                 ptr += *ptr == '.' ? 1 : 2;
2828                                 if (!*ptr)
2829                                         break;
2830                                 goto skip_more;
2831                         }
2832                         /*
2833                          * Once again, we can skip the delimiter that came
2834                          * after the string.
2835                          */
2836                         continue;
2837                 }
2838         }
2839 }
2840
2841 static void add_str_to_module(struct module *module, char *str)
2842 {
2843         struct module_string *modstr;
2844
2845         modstr = kmalloc(sizeof(*modstr), GFP_KERNEL);
2846
2847         /*
2848          * If we failed to allocate memory here, then we'll just
2849          * let the str memory leak when the module is removed.
2850          * If this fails to allocate, there's worse problems than
2851          * a leaked string on module removal.
2852          */
2853         if (WARN_ON_ONCE(!modstr))
2854                 return;
2855
2856         modstr->module = module;
2857         modstr->str = str;
2858
2859         list_add(&modstr->next, &module_strings);
2860 }
2861
2862 static void update_event_fields(struct trace_event_call *call,
2863                                 struct trace_eval_map *map)
2864 {
2865         struct ftrace_event_field *field;
2866         struct list_head *head;
2867         char *ptr;
2868         char *str;
2869         int len = strlen(map->eval_string);
2870
2871         /* Dynamic events should never have field maps */
2872         if (WARN_ON_ONCE(call->flags & TRACE_EVENT_FL_DYNAMIC))
2873                 return;
2874
2875         head = trace_get_fields(call);
2876         list_for_each_entry(field, head, link) {
2877                 ptr = strchr(field->type, '[');
2878                 if (!ptr)
2879                         continue;
2880                 ptr++;
2881
2882                 if (!isalpha(*ptr) && *ptr != '_')
2883                         continue;
2884
2885                 if (strncmp(map->eval_string, ptr, len) != 0)
2886                         continue;
2887
2888                 str = kstrdup(field->type, GFP_KERNEL);
2889                 if (WARN_ON_ONCE(!str))
2890                         return;
2891                 ptr = str + (ptr - field->type);
2892                 ptr = eval_replace(ptr, map, len);
2893                 /* enum/sizeof string smaller than value */
2894                 if (WARN_ON_ONCE(!ptr)) {
2895                         kfree(str);
2896                         continue;
2897                 }
2898
2899                 /*
2900                  * If the event is part of a module, then we need to free the string
2901                  * when the module is removed. Otherwise, it will stay allocated
2902                  * until a reboot.
2903                  */
2904                 if (call->module)
2905                         add_str_to_module(call->module, str);
2906
2907                 field->type = str;
2908         }
2909 }
2910
2911 void trace_event_eval_update(struct trace_eval_map **map, int len)
2912 {
2913         struct trace_event_call *call, *p;
2914         const char *last_system = NULL;
2915         bool first = false;
2916         int last_i;
2917         int i;
2918
2919         down_write(&trace_event_sem);
2920         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2921                 /* events are usually grouped together with systems */
2922                 if (!last_system || call->class->system != last_system) {
2923                         first = true;
2924                         last_i = 0;
2925                         last_system = call->class->system;
2926                 }
2927
2928                 /*
2929                  * Since calls are grouped by systems, the likelihood that the
2930                  * next call in the iteration belongs to the same system as the
2931                  * previous call is high. As an optimization, we skip searching
2932                  * for a map[] that matches the call's system if the last call
2933                  * was from the same system. That's what last_i is for. If the
2934                  * call has the same system as the previous call, then last_i
2935                  * will be the index of the first map[] that has a matching
2936                  * system.
2937                  */
2938                 for (i = last_i; i < len; i++) {
2939                         if (call->class->system == map[i]->system) {
2940                                 /* Save the first system if need be */
2941                                 if (first) {
2942                                         last_i = i;
2943                                         first = false;
2944                                 }
2945                                 update_event_printk(call, map[i]);
2946                                 update_event_fields(call, map[i]);
2947                         }
2948                 }
2949                 cond_resched();
2950         }
2951         up_write(&trace_event_sem);
2952 }
2953
2954 static bool event_in_systems(struct trace_event_call *call,
2955                              const char *systems)
2956 {
2957         const char *system;
2958         const char *p;
2959
2960         if (!systems)
2961                 return true;
2962
2963         system = call->class->system;
2964         p = strstr(systems, system);
2965         if (!p)
2966                 return false;
2967
2968         if (p != systems && !isspace(*(p - 1)) && *(p - 1) != ',')
2969                 return false;
2970
2971         p += strlen(system);
2972         return !*p || isspace(*p) || *p == ',';
2973 }
2974
2975 static struct trace_event_file *
2976 trace_create_new_event(struct trace_event_call *call,
2977                        struct trace_array *tr)
2978 {
2979         struct trace_pid_list *no_pid_list;
2980         struct trace_pid_list *pid_list;
2981         struct trace_event_file *file;
2982         unsigned int first;
2983
2984         if (!event_in_systems(call, tr->system_names))
2985                 return NULL;
2986
2987         file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2988         if (!file)
2989                 return ERR_PTR(-ENOMEM);
2990
2991         pid_list = rcu_dereference_protected(tr->filtered_pids,
2992                                              lockdep_is_held(&event_mutex));
2993         no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
2994                                              lockdep_is_held(&event_mutex));
2995
2996         if (!trace_pid_list_first(pid_list, &first) ||
2997             !trace_pid_list_first(no_pid_list, &first))
2998                 file->flags |= EVENT_FILE_FL_PID_FILTER;
2999
3000         file->event_call = call;
3001         file->tr = tr;
3002         atomic_set(&file->sm_ref, 0);
3003         atomic_set(&file->tm_ref, 0);
3004         INIT_LIST_HEAD(&file->triggers);
3005         list_add(&file->list, &tr->events);
3006         refcount_set(&file->ref, 1);
3007
3008         return file;
3009 }
3010
3011 #define MAX_BOOT_TRIGGERS 32
3012
3013 static struct boot_triggers {
3014         const char              *event;
3015         char                    *trigger;
3016 } bootup_triggers[MAX_BOOT_TRIGGERS];
3017
3018 static char bootup_trigger_buf[COMMAND_LINE_SIZE];
3019 static int nr_boot_triggers;
3020
3021 static __init int setup_trace_triggers(char *str)
3022 {
3023         char *trigger;
3024         char *buf;
3025         int i;
3026
3027         strscpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE);
3028         trace_set_ring_buffer_expanded(NULL);
3029         disable_tracing_selftest("running event triggers");
3030
3031         buf = bootup_trigger_buf;
3032         for (i = 0; i < MAX_BOOT_TRIGGERS; i++) {
3033                 trigger = strsep(&buf, ",");
3034                 if (!trigger)
3035                         break;
3036                 bootup_triggers[i].event = strsep(&trigger, ".");
3037                 bootup_triggers[i].trigger = trigger;
3038                 if (!bootup_triggers[i].trigger)
3039                         break;
3040         }
3041
3042         nr_boot_triggers = i;
3043         return 1;
3044 }
3045 __setup("trace_trigger=", setup_trace_triggers);
3046
3047 /* Add an event to a trace directory */
3048 static int
3049 __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
3050 {
3051         struct trace_event_file *file;
3052
3053         file = trace_create_new_event(call, tr);
3054         /*
3055          * trace_create_new_event() returns ERR_PTR(-ENOMEM) if failed
3056          * allocation, or NULL if the event is not part of the tr->system_names.
3057          * When the event is not part of the tr->system_names, return zero, not
3058          * an error.
3059          */
3060         if (!file)
3061                 return 0;
3062
3063         if (IS_ERR(file))
3064                 return PTR_ERR(file);
3065
3066         if (eventdir_initialized)
3067                 return event_create_dir(tr->event_dir, file);
3068         else
3069                 return event_define_fields(call);
3070 }
3071
3072 static void trace_early_triggers(struct trace_event_file *file, const char *name)
3073 {
3074         int ret;
3075         int i;
3076
3077         for (i = 0; i < nr_boot_triggers; i++) {
3078                 if (strcmp(name, bootup_triggers[i].event))
3079                         continue;
3080                 mutex_lock(&event_mutex);
3081                 ret = trigger_process_regex(file, bootup_triggers[i].trigger);
3082                 mutex_unlock(&event_mutex);
3083                 if (ret)
3084                         pr_err("Failed to register trigger '%s' on event %s\n",
3085                                bootup_triggers[i].trigger,
3086                                bootup_triggers[i].event);
3087         }
3088 }
3089
3090 /*
3091  * Just create a descriptor for early init. A descriptor is required
3092  * for enabling events at boot. We want to enable events before
3093  * the filesystem is initialized.
3094  */
3095 static int
3096 __trace_early_add_new_event(struct trace_event_call *call,
3097                             struct trace_array *tr)
3098 {
3099         struct trace_event_file *file;
3100         int ret;
3101
3102         file = trace_create_new_event(call, tr);
3103         /*
3104          * trace_create_new_event() returns ERR_PTR(-ENOMEM) if failed
3105          * allocation, or NULL if the event is not part of the tr->system_names.
3106          * When the event is not part of the tr->system_names, return zero, not
3107          * an error.
3108          */
3109         if (!file)
3110                 return 0;
3111
3112         if (IS_ERR(file))
3113                 return PTR_ERR(file);
3114
3115         ret = event_define_fields(call);
3116         if (ret)
3117                 return ret;
3118
3119         trace_early_triggers(file, trace_event_name(call));
3120
3121         return 0;
3122 }
3123
3124 struct ftrace_module_file_ops;
3125 static void __add_event_to_tracers(struct trace_event_call *call);
3126
3127 /* Add an additional event_call dynamically */
3128 int trace_add_event_call(struct trace_event_call *call)
3129 {
3130         int ret;
3131         lockdep_assert_held(&event_mutex);
3132
3133         mutex_lock(&trace_types_lock);
3134
3135         ret = __register_event(call, NULL);
3136         if (ret >= 0)
3137                 __add_event_to_tracers(call);
3138
3139         mutex_unlock(&trace_types_lock);
3140         return ret;
3141 }
3142 EXPORT_SYMBOL_GPL(trace_add_event_call);
3143
3144 /*
3145  * Must be called under locking of trace_types_lock, event_mutex and
3146  * trace_event_sem.
3147  */
3148 static void __trace_remove_event_call(struct trace_event_call *call)
3149 {
3150         event_remove(call);
3151         trace_destroy_fields(call);
3152         free_event_filter(call->filter);
3153         call->filter = NULL;
3154 }
3155
3156 static int probe_remove_event_call(struct trace_event_call *call)
3157 {
3158         struct trace_array *tr;
3159         struct trace_event_file *file;
3160
3161 #ifdef CONFIG_PERF_EVENTS
3162         if (call->perf_refcount)
3163                 return -EBUSY;
3164 #endif
3165         do_for_each_event_file(tr, file) {
3166                 if (file->event_call != call)
3167                         continue;
3168                 /*
3169                  * We can't rely on ftrace_event_enable_disable(enable => 0)
3170                  * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
3171                  * TRACE_REG_UNREGISTER.
3172                  */
3173                 if (file->flags & EVENT_FILE_FL_ENABLED)
3174                         goto busy;
3175
3176                 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
3177                         tr->clear_trace = true;
3178                 /*
3179                  * The do_for_each_event_file_safe() is
3180                  * a double loop. After finding the call for this
3181                  * trace_array, we use break to jump to the next
3182                  * trace_array.
3183                  */
3184                 break;
3185         } while_for_each_event_file();
3186
3187         __trace_remove_event_call(call);
3188
3189         return 0;
3190  busy:
3191         /* No need to clear the trace now */
3192         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
3193                 tr->clear_trace = false;
3194         }
3195         return -EBUSY;
3196 }
3197
3198 /* Remove an event_call */
3199 int trace_remove_event_call(struct trace_event_call *call)
3200 {
3201         int ret;
3202
3203         lockdep_assert_held(&event_mutex);
3204
3205         mutex_lock(&trace_types_lock);
3206         down_write(&trace_event_sem);
3207         ret = probe_remove_event_call(call);
3208         up_write(&trace_event_sem);
3209         mutex_unlock(&trace_types_lock);
3210
3211         return ret;
3212 }
3213 EXPORT_SYMBOL_GPL(trace_remove_event_call);
3214
3215 #define for_each_event(event, start, end)                       \
3216         for (event = start;                                     \
3217              (unsigned long)event < (unsigned long)end;         \
3218              event++)
3219
3220 #ifdef CONFIG_MODULES
3221
3222 static void trace_module_add_events(struct module *mod)
3223 {
3224         struct trace_event_call **call, **start, **end;
3225
3226         if (!mod->num_trace_events)
3227                 return;
3228
3229         /* Don't add infrastructure for mods without tracepoints */
3230         if (trace_module_has_bad_taint(mod)) {
3231                 pr_err("%s: module has bad taint, not creating trace events\n",
3232                        mod->name);
3233                 return;
3234         }
3235
3236         start = mod->trace_events;
3237         end = mod->trace_events + mod->num_trace_events;
3238
3239         for_each_event(call, start, end) {
3240                 __register_event(*call, mod);
3241                 __add_event_to_tracers(*call);
3242         }
3243 }
3244
3245 static void trace_module_remove_events(struct module *mod)
3246 {
3247         struct trace_event_call *call, *p;
3248         struct module_string *modstr, *m;
3249
3250         down_write(&trace_event_sem);
3251         list_for_each_entry_safe(call, p, &ftrace_events, list) {
3252                 if ((call->flags & TRACE_EVENT_FL_DYNAMIC) || !call->module)
3253                         continue;
3254                 if (call->module == mod)
3255                         __trace_remove_event_call(call);
3256         }
3257         /* Check for any strings allocade for this module */
3258         list_for_each_entry_safe(modstr, m, &module_strings, next) {
3259                 if (modstr->module != mod)
3260                         continue;
3261                 list_del(&modstr->next);
3262                 kfree(modstr->str);
3263                 kfree(modstr);
3264         }
3265         up_write(&trace_event_sem);
3266
3267         /*
3268          * It is safest to reset the ring buffer if the module being unloaded
3269          * registered any events that were used. The only worry is if
3270          * a new module gets loaded, and takes on the same id as the events
3271          * of this module. When printing out the buffer, traced events left
3272          * over from this module may be passed to the new module events and
3273          * unexpected results may occur.
3274          */
3275         tracing_reset_all_online_cpus_unlocked();
3276 }
3277
3278 static int trace_module_notify(struct notifier_block *self,
3279                                unsigned long val, void *data)
3280 {
3281         struct module *mod = data;
3282
3283         mutex_lock(&event_mutex);
3284         mutex_lock(&trace_types_lock);
3285         switch (val) {
3286         case MODULE_STATE_COMING:
3287                 trace_module_add_events(mod);
3288                 break;
3289         case MODULE_STATE_GOING:
3290                 trace_module_remove_events(mod);
3291                 break;
3292         }
3293         mutex_unlock(&trace_types_lock);
3294         mutex_unlock(&event_mutex);
3295
3296         return NOTIFY_OK;
3297 }
3298
3299 static struct notifier_block trace_module_nb = {
3300         .notifier_call = trace_module_notify,
3301         .priority = 1, /* higher than trace.c module notify */
3302 };
3303 #endif /* CONFIG_MODULES */
3304
3305 /* Create a new event directory structure for a trace directory. */
3306 static void
3307 __trace_add_event_dirs(struct trace_array *tr)
3308 {
3309         struct trace_event_call *call;
3310         int ret;
3311
3312         list_for_each_entry(call, &ftrace_events, list) {
3313                 ret = __trace_add_new_event(call, tr);
3314                 if (ret < 0)
3315                         pr_warn("Could not create directory for event %s\n",
3316                                 trace_event_name(call));
3317         }
3318 }
3319
3320 /* Returns any file that matches the system and event */
3321 struct trace_event_file *
3322 __find_event_file(struct trace_array *tr, const char *system, const char *event)
3323 {
3324         struct trace_event_file *file;
3325         struct trace_event_call *call;
3326         const char *name;
3327
3328         list_for_each_entry(file, &tr->events, list) {
3329
3330                 call = file->event_call;
3331                 name = trace_event_name(call);
3332
3333                 if (!name || !call->class)
3334                         continue;
3335
3336                 if (strcmp(event, name) == 0 &&
3337                     strcmp(system, call->class->system) == 0)
3338                         return file;
3339         }
3340         return NULL;
3341 }
3342
3343 /* Returns valid trace event files that match system and event */
3344 struct trace_event_file *
3345 find_event_file(struct trace_array *tr, const char *system, const char *event)
3346 {
3347         struct trace_event_file *file;
3348
3349         file = __find_event_file(tr, system, event);
3350         if (!file || !file->event_call->class->reg ||
3351             file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
3352                 return NULL;
3353
3354         return file;
3355 }
3356
3357 /**
3358  * trace_get_event_file - Find and return a trace event file
3359  * @instance: The name of the trace instance containing the event
3360  * @system: The name of the system containing the event
3361  * @event: The name of the event
3362  *
3363  * Return a trace event file given the trace instance name, trace
3364  * system, and trace event name.  If the instance name is NULL, it
3365  * refers to the top-level trace array.
3366  *
3367  * This function will look it up and return it if found, after calling
3368  * trace_array_get() to prevent the instance from going away, and
3369  * increment the event's module refcount to prevent it from being
3370  * removed.
3371  *
3372  * To release the file, call trace_put_event_file(), which will call
3373  * trace_array_put() and decrement the event's module refcount.
3374  *
3375  * Return: The trace event on success, ERR_PTR otherwise.
3376  */
3377 struct trace_event_file *trace_get_event_file(const char *instance,
3378                                               const char *system,
3379                                               const char *event)
3380 {
3381         struct trace_array *tr = top_trace_array();
3382         struct trace_event_file *file = NULL;
3383         int ret = -EINVAL;
3384
3385         if (instance) {
3386                 tr = trace_array_find_get(instance);
3387                 if (!tr)
3388                         return ERR_PTR(-ENOENT);
3389         } else {
3390                 ret = trace_array_get(tr);
3391                 if (ret)
3392                         return ERR_PTR(ret);
3393         }
3394
3395         mutex_lock(&event_mutex);
3396
3397         file = find_event_file(tr, system, event);
3398         if (!file) {
3399                 trace_array_put(tr);
3400                 ret = -EINVAL;
3401                 goto out;
3402         }
3403
3404         /* Don't let event modules unload while in use */
3405         ret = trace_event_try_get_ref(file->event_call);
3406         if (!ret) {
3407                 trace_array_put(tr);
3408                 ret = -EBUSY;
3409                 goto out;
3410         }
3411
3412         ret = 0;
3413  out:
3414         mutex_unlock(&event_mutex);
3415
3416         if (ret)
3417                 file = ERR_PTR(ret);
3418
3419         return file;
3420 }
3421 EXPORT_SYMBOL_GPL(trace_get_event_file);
3422
3423 /**
3424  * trace_put_event_file - Release a file from trace_get_event_file()
3425  * @file: The trace event file
3426  *
3427  * If a file was retrieved using trace_get_event_file(), this should
3428  * be called when it's no longer needed.  It will cancel the previous
3429  * trace_array_get() called by that function, and decrement the
3430  * event's module refcount.
3431  */
3432 void trace_put_event_file(struct trace_event_file *file)
3433 {
3434         mutex_lock(&event_mutex);
3435         trace_event_put_ref(file->event_call);
3436         mutex_unlock(&event_mutex);
3437
3438         trace_array_put(file->tr);
3439 }
3440 EXPORT_SYMBOL_GPL(trace_put_event_file);
3441
3442 #ifdef CONFIG_DYNAMIC_FTRACE
3443
3444 /* Avoid typos */
3445 #define ENABLE_EVENT_STR        "enable_event"
3446 #define DISABLE_EVENT_STR       "disable_event"
3447
3448 struct event_probe_data {
3449         struct trace_event_file *file;
3450         unsigned long                   count;
3451         int                             ref;
3452         bool                            enable;
3453 };
3454
3455 static void update_event_probe(struct event_probe_data *data)
3456 {
3457         if (data->enable)
3458                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3459         else
3460                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3461 }
3462
3463 static void
3464 event_enable_probe(unsigned long ip, unsigned long parent_ip,
3465                    struct trace_array *tr, struct ftrace_probe_ops *ops,
3466                    void *data)
3467 {
3468         struct ftrace_func_mapper *mapper = data;
3469         struct event_probe_data *edata;
3470         void **pdata;
3471
3472         pdata = ftrace_func_mapper_find_ip(mapper, ip);
3473         if (!pdata || !*pdata)
3474                 return;
3475
3476         edata = *pdata;
3477         update_event_probe(edata);
3478 }
3479
3480 static void
3481 event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
3482                          struct trace_array *tr, struct ftrace_probe_ops *ops,
3483                          void *data)
3484 {
3485         struct ftrace_func_mapper *mapper = data;
3486         struct event_probe_data *edata;
3487         void **pdata;
3488
3489         pdata = ftrace_func_mapper_find_ip(mapper, ip);
3490         if (!pdata || !*pdata)
3491                 return;
3492
3493         edata = *pdata;
3494
3495         if (!edata->count)
3496                 return;
3497
3498         /* Skip if the event is in a state we want to switch to */
3499         if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
3500                 return;
3501
3502         if (edata->count != -1)
3503                 (edata->count)--;
3504
3505         update_event_probe(edata);
3506 }
3507
3508 static int
3509 event_enable_print(struct seq_file *m, unsigned long ip,
3510                    struct ftrace_probe_ops *ops, void *data)
3511 {
3512         struct ftrace_func_mapper *mapper = data;
3513         struct event_probe_data *edata;
3514         void **pdata;
3515
3516         pdata = ftrace_func_mapper_find_ip(mapper, ip);
3517
3518         if (WARN_ON_ONCE(!pdata || !*pdata))
3519                 return 0;
3520
3521         edata = *pdata;
3522
3523         seq_printf(m, "%ps:", (void *)ip);
3524
3525         seq_printf(m, "%s:%s:%s",
3526                    edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
3527                    edata->file->event_call->class->system,
3528                    trace_event_name(edata->file->event_call));
3529
3530         if (edata->count == -1)
3531                 seq_puts(m, ":unlimited\n");
3532         else
3533                 seq_printf(m, ":count=%ld\n", edata->count);
3534
3535         return 0;
3536 }
3537
3538 static int
3539 event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
3540                   unsigned long ip, void *init_data, void **data)
3541 {
3542         struct ftrace_func_mapper *mapper = *data;
3543         struct event_probe_data *edata = init_data;
3544         int ret;
3545
3546         if (!mapper) {
3547                 mapper = allocate_ftrace_func_mapper();
3548                 if (!mapper)
3549                         return -ENODEV;
3550                 *data = mapper;
3551         }
3552
3553         ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
3554         if (ret < 0)
3555                 return ret;
3556
3557         edata->ref++;
3558
3559         return 0;
3560 }
3561
3562 static int free_probe_data(void *data)
3563 {
3564         struct event_probe_data *edata = data;
3565
3566         edata->ref--;
3567         if (!edata->ref) {
3568                 /* Remove the SOFT_MODE flag */
3569                 __ftrace_event_enable_disable(edata->file, 0, 1);
3570                 trace_event_put_ref(edata->file->event_call);
3571                 kfree(edata);
3572         }
3573         return 0;
3574 }
3575
3576 static void
3577 event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
3578                   unsigned long ip, void *data)
3579 {
3580         struct ftrace_func_mapper *mapper = data;
3581         struct event_probe_data *edata;
3582
3583         if (!ip) {
3584                 if (!mapper)
3585                         return;
3586                 free_ftrace_func_mapper(mapper, free_probe_data);
3587                 return;
3588         }
3589
3590         edata = ftrace_func_mapper_remove_ip(mapper, ip);
3591
3592         if (WARN_ON_ONCE(!edata))
3593                 return;
3594
3595         if (WARN_ON_ONCE(edata->ref <= 0))
3596                 return;
3597
3598         free_probe_data(edata);
3599 }
3600
3601 static struct ftrace_probe_ops event_enable_probe_ops = {
3602         .func                   = event_enable_probe,
3603         .print                  = event_enable_print,
3604         .init                   = event_enable_init,
3605         .free                   = event_enable_free,
3606 };
3607
3608 static struct ftrace_probe_ops event_enable_count_probe_ops = {
3609         .func                   = event_enable_count_probe,
3610         .print                  = event_enable_print,
3611         .init                   = event_enable_init,
3612         .free                   = event_enable_free,
3613 };
3614
3615 static struct ftrace_probe_ops event_disable_probe_ops = {
3616         .func                   = event_enable_probe,
3617         .print                  = event_enable_print,
3618         .init                   = event_enable_init,
3619         .free                   = event_enable_free,
3620 };
3621
3622 static struct ftrace_probe_ops event_disable_count_probe_ops = {
3623         .func                   = event_enable_count_probe,
3624         .print                  = event_enable_print,
3625         .init                   = event_enable_init,
3626         .free                   = event_enable_free,
3627 };
3628
3629 static int
3630 event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
3631                   char *glob, char *cmd, char *param, int enabled)
3632 {
3633         struct trace_event_file *file;
3634         struct ftrace_probe_ops *ops;
3635         struct event_probe_data *data;
3636         const char *system;
3637         const char *event;
3638         char *number;
3639         bool enable;
3640         int ret;
3641
3642         if (!tr)
3643                 return -ENODEV;
3644
3645         /* hash funcs only work with set_ftrace_filter */
3646         if (!enabled || !param)
3647                 return -EINVAL;
3648
3649         system = strsep(&param, ":");
3650         if (!param)
3651                 return -EINVAL;
3652
3653         event = strsep(&param, ":");
3654
3655         mutex_lock(&event_mutex);
3656
3657         ret = -EINVAL;
3658         file = find_event_file(tr, system, event);
3659         if (!file)
3660                 goto out;
3661
3662         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
3663
3664         if (enable)
3665                 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
3666         else
3667                 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
3668
3669         if (glob[0] == '!') {
3670                 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
3671                 goto out;
3672         }
3673
3674         ret = -ENOMEM;
3675
3676         data = kzalloc(sizeof(*data), GFP_KERNEL);
3677         if (!data)
3678                 goto out;
3679
3680         data->enable = enable;
3681         data->count = -1;
3682         data->file = file;
3683
3684         if (!param)
3685                 goto out_reg;
3686
3687         number = strsep(&param, ":");
3688
3689         ret = -EINVAL;
3690         if (!strlen(number))
3691                 goto out_free;
3692
3693         /*
3694          * We use the callback data field (which is a pointer)
3695          * as our counter.
3696          */
3697         ret = kstrtoul(number, 0, &data->count);
3698         if (ret)
3699                 goto out_free;
3700
3701  out_reg:
3702         /* Don't let event modules unload while probe registered */
3703         ret = trace_event_try_get_ref(file->event_call);
3704         if (!ret) {
3705                 ret = -EBUSY;
3706                 goto out_free;
3707         }
3708
3709         ret = __ftrace_event_enable_disable(file, 1, 1);
3710         if (ret < 0)
3711                 goto out_put;
3712
3713         ret = register_ftrace_function_probe(glob, tr, ops, data);
3714         /*
3715          * The above returns on success the # of functions enabled,
3716          * but if it didn't find any functions it returns zero.
3717          * Consider no functions a failure too.
3718          */
3719         if (!ret) {
3720                 ret = -ENOENT;
3721                 goto out_disable;
3722         } else if (ret < 0)
3723                 goto out_disable;
3724         /* Just return zero, not the number of enabled functions */
3725         ret = 0;
3726  out:
3727         mutex_unlock(&event_mutex);
3728         return ret;
3729
3730  out_disable:
3731         __ftrace_event_enable_disable(file, 0, 1);
3732  out_put:
3733         trace_event_put_ref(file->event_call);
3734  out_free:
3735         kfree(data);
3736         goto out;
3737 }
3738
3739 static struct ftrace_func_command event_enable_cmd = {
3740         .name                   = ENABLE_EVENT_STR,
3741         .func                   = event_enable_func,
3742 };
3743
3744 static struct ftrace_func_command event_disable_cmd = {
3745         .name                   = DISABLE_EVENT_STR,
3746         .func                   = event_enable_func,
3747 };
3748
3749 static __init int register_event_cmds(void)
3750 {
3751         int ret;
3752
3753         ret = register_ftrace_command(&event_enable_cmd);
3754         if (WARN_ON(ret < 0))
3755                 return ret;
3756         ret = register_ftrace_command(&event_disable_cmd);
3757         if (WARN_ON(ret < 0))
3758                 unregister_ftrace_command(&event_enable_cmd);
3759         return ret;
3760 }
3761 #else
3762 static inline int register_event_cmds(void) { return 0; }
3763 #endif /* CONFIG_DYNAMIC_FTRACE */
3764
3765 /*
3766  * The top level array and trace arrays created by boot-time tracing
3767  * have already had its trace_event_file descriptors created in order
3768  * to allow for early events to be recorded.
3769  * This function is called after the tracefs has been initialized,
3770  * and we now have to create the files associated to the events.
3771  */
3772 static void __trace_early_add_event_dirs(struct trace_array *tr)
3773 {
3774         struct trace_event_file *file;
3775         int ret;
3776
3777
3778         list_for_each_entry(file, &tr->events, list) {
3779                 ret = event_create_dir(tr->event_dir, file);
3780                 if (ret < 0)
3781                         pr_warn("Could not create directory for event %s\n",
3782                                 trace_event_name(file->event_call));
3783         }
3784 }
3785
3786 /*
3787  * For early boot up, the top trace array and the trace arrays created
3788  * by boot-time tracing require to have a list of events that can be
3789  * enabled. This must be done before the filesystem is set up in order
3790  * to allow events to be traced early.
3791  */
3792 void __trace_early_add_events(struct trace_array *tr)
3793 {
3794         struct trace_event_call *call;
3795         int ret;
3796
3797         list_for_each_entry(call, &ftrace_events, list) {
3798                 /* Early boot up should not have any modules loaded */
3799                 if (!(call->flags & TRACE_EVENT_FL_DYNAMIC) &&
3800                     WARN_ON_ONCE(call->module))
3801                         continue;
3802
3803                 ret = __trace_early_add_new_event(call, tr);
3804                 if (ret < 0)
3805                         pr_warn("Could not create early event %s\n",
3806                                 trace_event_name(call));
3807         }
3808 }
3809
3810 /* Remove the event directory structure for a trace directory. */
3811 static void
3812 __trace_remove_event_dirs(struct trace_array *tr)
3813 {
3814         struct trace_event_file *file, *next;
3815
3816         list_for_each_entry_safe(file, next, &tr->events, list)
3817                 remove_event_file_dir(file);
3818 }
3819
3820 static void __add_event_to_tracers(struct trace_event_call *call)
3821 {
3822         struct trace_array *tr;
3823
3824         list_for_each_entry(tr, &ftrace_trace_arrays, list)
3825                 __trace_add_new_event(call, tr);
3826 }
3827
3828 extern struct trace_event_call *__start_ftrace_events[];
3829 extern struct trace_event_call *__stop_ftrace_events[];
3830
3831 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
3832
3833 static __init int setup_trace_event(char *str)
3834 {
3835         strscpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
3836         trace_set_ring_buffer_expanded(NULL);
3837         disable_tracing_selftest("running event tracing");
3838
3839         return 1;
3840 }
3841 __setup("trace_event=", setup_trace_event);
3842
3843 static int events_callback(const char *name, umode_t *mode, void **data,
3844                            const struct file_operations **fops)
3845 {
3846         if (strcmp(name, "enable") == 0) {
3847                 *mode = TRACE_MODE_WRITE;
3848                 *fops = &ftrace_tr_enable_fops;
3849                 return 1;
3850         }
3851
3852         if (strcmp(name, "header_page") == 0) {
3853                 *mode = TRACE_MODE_READ;
3854                 *fops = &ftrace_show_header_page_fops;
3855
3856         } else if (strcmp(name, "header_event") == 0) {
3857                 *mode = TRACE_MODE_READ;
3858                 *fops = &ftrace_show_header_event_fops;
3859         } else
3860                 return 0;
3861
3862         return 1;
3863 }
3864
3865 /* Expects to have event_mutex held when called */
3866 static int
3867 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
3868 {
3869         struct eventfs_inode *e_events;
3870         struct dentry *entry;
3871         int nr_entries;
3872         static struct eventfs_entry events_entries[] = {
3873                 {
3874                         .name           = "enable",
3875                         .callback       = events_callback,
3876                 },
3877                 {
3878                         .name           = "header_page",
3879                         .callback       = events_callback,
3880                 },
3881                 {
3882                         .name           = "header_event",
3883                         .callback       = events_callback,
3884                 },
3885         };
3886
3887         entry = trace_create_file("set_event", TRACE_MODE_WRITE, parent,
3888                                   tr, &ftrace_set_event_fops);
3889         if (!entry)
3890                 return -ENOMEM;
3891
3892         nr_entries = ARRAY_SIZE(events_entries);
3893
3894         e_events = eventfs_create_events_dir("events", parent, events_entries,
3895                                              nr_entries, tr);
3896         if (IS_ERR(e_events)) {
3897                 pr_warn("Could not create tracefs 'events' directory\n");
3898                 return -ENOMEM;
3899         }
3900
3901         /* There are not as crucial, just warn if they are not created */
3902
3903         trace_create_file("set_event_pid", TRACE_MODE_WRITE, parent,
3904                           tr, &ftrace_set_event_pid_fops);
3905
3906         trace_create_file("set_event_notrace_pid",
3907                           TRACE_MODE_WRITE, parent, tr,
3908                           &ftrace_set_event_notrace_pid_fops);
3909
3910         tr->event_dir = e_events;
3911
3912         return 0;
3913 }
3914
3915 /**
3916  * event_trace_add_tracer - add a instance of a trace_array to events
3917  * @parent: The parent dentry to place the files/directories for events in
3918  * @tr: The trace array associated with these events
3919  *
3920  * When a new instance is created, it needs to set up its events
3921  * directory, as well as other files associated with events. It also
3922  * creates the event hierarchy in the @parent/events directory.
3923  *
3924  * Returns 0 on success.
3925  *
3926  * Must be called with event_mutex held.
3927  */
3928 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
3929 {
3930         int ret;
3931
3932         lockdep_assert_held(&event_mutex);
3933
3934         ret = create_event_toplevel_files(parent, tr);
3935         if (ret)
3936                 goto out;
3937
3938         down_write(&trace_event_sem);
3939         /* If tr already has the event list, it is initialized in early boot. */
3940         if (unlikely(!list_empty(&tr->events)))
3941                 __trace_early_add_event_dirs(tr);
3942         else
3943                 __trace_add_event_dirs(tr);
3944         up_write(&trace_event_sem);
3945
3946  out:
3947         return ret;
3948 }
3949
3950 /*
3951  * The top trace array already had its file descriptors created.
3952  * Now the files themselves need to be created.
3953  */
3954 static __init int
3955 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
3956 {
3957         int ret;
3958
3959         mutex_lock(&event_mutex);
3960
3961         ret = create_event_toplevel_files(parent, tr);
3962         if (ret)
3963                 goto out_unlock;
3964
3965         down_write(&trace_event_sem);
3966         __trace_early_add_event_dirs(tr);
3967         up_write(&trace_event_sem);
3968
3969  out_unlock:
3970         mutex_unlock(&event_mutex);
3971
3972         return ret;
3973 }
3974
3975 /* Must be called with event_mutex held */
3976 int event_trace_del_tracer(struct trace_array *tr)
3977 {
3978         lockdep_assert_held(&event_mutex);
3979
3980         /* Disable any event triggers and associated soft-disabled events */
3981         clear_event_triggers(tr);
3982
3983         /* Clear the pid list */
3984         __ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
3985
3986         /* Disable any running events */
3987         __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3988
3989         /* Make sure no more events are being executed */
3990         tracepoint_synchronize_unregister();
3991
3992         down_write(&trace_event_sem);
3993         __trace_remove_event_dirs(tr);
3994         eventfs_remove_events_dir(tr->event_dir);
3995         up_write(&trace_event_sem);
3996
3997         tr->event_dir = NULL;
3998
3999         return 0;
4000 }
4001
4002 static __init int event_trace_memsetup(void)
4003 {
4004         field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
4005         file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
4006         return 0;
4007 }
4008
4009 __init void
4010 early_enable_events(struct trace_array *tr, char *buf, bool disable_first)
4011 {
4012         char *token;
4013         int ret;
4014
4015         while (true) {
4016                 token = strsep(&buf, ",");
4017
4018                 if (!token)
4019                         break;
4020
4021                 if (*token) {
4022                         /* Restarting syscalls requires that we stop them first */
4023                         if (disable_first)
4024                                 ftrace_set_clr_event(tr, token, 0);
4025
4026                         ret = ftrace_set_clr_event(tr, token, 1);
4027                         if (ret)
4028                                 pr_warn("Failed to enable trace event: %s\n", token);
4029                 }
4030
4031                 /* Put back the comma to allow this to be called again */
4032                 if (buf)
4033                         *(buf - 1) = ',';
4034         }
4035 }
4036
4037 static __init int event_trace_enable(void)
4038 {
4039         struct trace_array *tr = top_trace_array();
4040         struct trace_event_call **iter, *call;
4041         int ret;
4042
4043         if (!tr)
4044                 return -ENODEV;
4045
4046         for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
4047
4048                 call = *iter;
4049                 ret = event_init(call);
4050                 if (!ret)
4051                         list_add(&call->list, &ftrace_events);
4052         }
4053
4054         register_trigger_cmds();
4055
4056         /*
4057          * We need the top trace array to have a working set of trace
4058          * points at early init, before the debug files and directories
4059          * are created. Create the file entries now, and attach them
4060          * to the actual file dentries later.
4061          */
4062         __trace_early_add_events(tr);
4063
4064         early_enable_events(tr, bootup_event_buf, false);
4065
4066         trace_printk_start_comm();
4067
4068         register_event_cmds();
4069
4070
4071         return 0;
4072 }
4073
4074 /*
4075  * event_trace_enable() is called from trace_event_init() first to
4076  * initialize events and perhaps start any events that are on the
4077  * command line. Unfortunately, there are some events that will not
4078  * start this early, like the system call tracepoints that need
4079  * to set the %SYSCALL_WORK_SYSCALL_TRACEPOINT flag of pid 1. But
4080  * event_trace_enable() is called before pid 1 starts, and this flag
4081  * is never set, making the syscall tracepoint never get reached, but
4082  * the event is enabled regardless (and not doing anything).
4083  */
4084 static __init int event_trace_enable_again(void)
4085 {
4086         struct trace_array *tr;
4087
4088         tr = top_trace_array();
4089         if (!tr)
4090                 return -ENODEV;
4091
4092         early_enable_events(tr, bootup_event_buf, true);
4093
4094         return 0;
4095 }
4096
4097 early_initcall(event_trace_enable_again);
4098
4099 /* Init fields which doesn't related to the tracefs */
4100 static __init int event_trace_init_fields(void)
4101 {
4102         if (trace_define_generic_fields())
4103                 pr_warn("tracing: Failed to allocated generic fields");
4104
4105         if (trace_define_common_fields())
4106                 pr_warn("tracing: Failed to allocate common fields");
4107
4108         return 0;
4109 }
4110
4111 __init int event_trace_init(void)
4112 {
4113         struct trace_array *tr;
4114         int ret;
4115
4116         tr = top_trace_array();
4117         if (!tr)
4118                 return -ENODEV;
4119
4120         trace_create_file("available_events", TRACE_MODE_READ,
4121                           NULL, tr, &ftrace_avail_fops);
4122
4123         ret = early_event_add_tracer(NULL, tr);
4124         if (ret)
4125                 return ret;
4126
4127 #ifdef CONFIG_MODULES
4128         ret = register_module_notifier(&trace_module_nb);
4129         if (ret)
4130                 pr_warn("Failed to register trace events module notifier\n");
4131 #endif
4132
4133         eventdir_initialized = true;
4134
4135         return 0;
4136 }
4137
4138 void __init trace_event_init(void)
4139 {
4140         event_trace_memsetup();
4141         init_ftrace_syscalls();
4142         event_trace_enable();
4143         event_trace_init_fields();
4144 }
4145
4146 #ifdef CONFIG_EVENT_TRACE_STARTUP_TEST
4147
4148 static DEFINE_SPINLOCK(test_spinlock);
4149 static DEFINE_SPINLOCK(test_spinlock_irq);
4150 static DEFINE_MUTEX(test_mutex);
4151
4152 static __init void test_work(struct work_struct *dummy)
4153 {
4154         spin_lock(&test_spinlock);
4155         spin_lock_irq(&test_spinlock_irq);
4156         udelay(1);
4157         spin_unlock_irq(&test_spinlock_irq);
4158         spin_unlock(&test_spinlock);
4159
4160         mutex_lock(&test_mutex);
4161         msleep(1);
4162         mutex_unlock(&test_mutex);
4163 }
4164
4165 static __init int event_test_thread(void *unused)
4166 {
4167         void *test_malloc;
4168
4169         test_malloc = kmalloc(1234, GFP_KERNEL);
4170         if (!test_malloc)
4171                 pr_info("failed to kmalloc\n");
4172
4173         schedule_on_each_cpu(test_work);
4174
4175         kfree(test_malloc);
4176
4177         set_current_state(TASK_INTERRUPTIBLE);
4178         while (!kthread_should_stop()) {
4179                 schedule();
4180                 set_current_state(TASK_INTERRUPTIBLE);
4181         }
4182         __set_current_state(TASK_RUNNING);
4183
4184         return 0;
4185 }
4186
4187 /*
4188  * Do various things that may trigger events.
4189  */
4190 static __init void event_test_stuff(void)
4191 {
4192         struct task_struct *test_thread;
4193
4194         test_thread = kthread_run(event_test_thread, NULL, "test-events");
4195         msleep(1);
4196         kthread_stop(test_thread);
4197 }
4198
4199 /*
4200  * For every trace event defined, we will test each trace point separately,
4201  * and then by groups, and finally all trace points.
4202  */
4203 static __init void event_trace_self_tests(void)
4204 {
4205         struct trace_subsystem_dir *dir;
4206         struct trace_event_file *file;
4207         struct trace_event_call *call;
4208         struct event_subsystem *system;
4209         struct trace_array *tr;
4210         int ret;
4211
4212         tr = top_trace_array();
4213         if (!tr)
4214                 return;
4215
4216         pr_info("Running tests on trace events:\n");
4217
4218         list_for_each_entry(file, &tr->events, list) {
4219
4220                 call = file->event_call;
4221
4222                 /* Only test those that have a probe */
4223                 if (!call->class || !call->class->probe)
4224                         continue;
4225
4226 /*
4227  * Testing syscall events here is pretty useless, but
4228  * we still do it if configured. But this is time consuming.
4229  * What we really need is a user thread to perform the
4230  * syscalls as we test.
4231  */
4232 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
4233                 if (call->class->system &&
4234                     strcmp(call->class->system, "syscalls") == 0)
4235                         continue;
4236 #endif
4237
4238                 pr_info("Testing event %s: ", trace_event_name(call));
4239
4240                 /*
4241                  * If an event is already enabled, someone is using
4242                  * it and the self test should not be on.
4243                  */
4244                 if (file->flags & EVENT_FILE_FL_ENABLED) {
4245                         pr_warn("Enabled event during self test!\n");
4246                         WARN_ON_ONCE(1);
4247                         continue;
4248                 }
4249
4250                 ftrace_event_enable_disable(file, 1);
4251                 event_test_stuff();
4252                 ftrace_event_enable_disable(file, 0);
4253
4254                 pr_cont("OK\n");
4255         }
4256
4257         /* Now test at the sub system level */
4258
4259         pr_info("Running tests on trace event systems:\n");
4260
4261         list_for_each_entry(dir, &tr->systems, list) {
4262
4263                 system = dir->subsystem;
4264
4265                 /* the ftrace system is special, skip it */
4266                 if (strcmp(system->name, "ftrace") == 0)
4267                         continue;
4268
4269                 pr_info("Testing event system %s: ", system->name);
4270
4271                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
4272                 if (WARN_ON_ONCE(ret)) {
4273                         pr_warn("error enabling system %s\n",
4274                                 system->name);
4275                         continue;
4276                 }
4277
4278                 event_test_stuff();
4279
4280                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
4281                 if (WARN_ON_ONCE(ret)) {
4282                         pr_warn("error disabling system %s\n",
4283                                 system->name);
4284                         continue;
4285                 }
4286
4287                 pr_cont("OK\n");
4288         }
4289
4290         /* Test with all events enabled */
4291
4292         pr_info("Running tests on all trace events:\n");
4293         pr_info("Testing all events: ");
4294
4295         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
4296         if (WARN_ON_ONCE(ret)) {
4297                 pr_warn("error enabling all events\n");
4298                 return;
4299         }
4300
4301         event_test_stuff();
4302
4303         /* reset sysname */
4304         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
4305         if (WARN_ON_ONCE(ret)) {
4306                 pr_warn("error disabling all events\n");
4307                 return;
4308         }
4309
4310         pr_cont("OK\n");
4311 }
4312
4313 #ifdef CONFIG_FUNCTION_TRACER
4314
4315 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
4316
4317 static struct trace_event_file event_trace_file __initdata;
4318
4319 static void __init
4320 function_test_events_call(unsigned long ip, unsigned long parent_ip,
4321                           struct ftrace_ops *op, struct ftrace_regs *regs)
4322 {
4323         struct trace_buffer *buffer;
4324         struct ring_buffer_event *event;
4325         struct ftrace_entry *entry;
4326         unsigned int trace_ctx;
4327         long disabled;
4328         int cpu;
4329
4330         trace_ctx = tracing_gen_ctx();
4331         preempt_disable_notrace();
4332         cpu = raw_smp_processor_id();
4333         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
4334
4335         if (disabled != 1)
4336                 goto out;
4337
4338         event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
4339                                                 TRACE_FN, sizeof(*entry),
4340                                                 trace_ctx);
4341         if (!event)
4342                 goto out;
4343         entry   = ring_buffer_event_data(event);
4344         entry->ip                       = ip;
4345         entry->parent_ip                = parent_ip;
4346
4347         event_trigger_unlock_commit(&event_trace_file, buffer, event,
4348                                     entry, trace_ctx);
4349  out:
4350         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
4351         preempt_enable_notrace();
4352 }
4353
4354 static struct ftrace_ops trace_ops __initdata  =
4355 {
4356         .func = function_test_events_call,
4357 };
4358
4359 static __init void event_trace_self_test_with_function(void)
4360 {
4361         int ret;
4362
4363         event_trace_file.tr = top_trace_array();
4364         if (WARN_ON(!event_trace_file.tr))
4365                 return;
4366
4367         ret = register_ftrace_function(&trace_ops);
4368         if (WARN_ON(ret < 0)) {
4369                 pr_info("Failed to enable function tracer for event tests\n");
4370                 return;
4371         }
4372         pr_info("Running tests again, along with the function tracer\n");
4373         event_trace_self_tests();
4374         unregister_ftrace_function(&trace_ops);
4375 }
4376 #else
4377 static __init void event_trace_self_test_with_function(void)
4378 {
4379 }
4380 #endif
4381
4382 static __init int event_trace_self_tests_init(void)
4383 {
4384         if (!tracing_selftest_disabled) {
4385                 event_trace_self_tests();
4386                 event_trace_self_test_with_function();
4387         }
4388
4389         return 0;
4390 }
4391
4392 late_initcall(event_trace_self_tests_init);
4393
4394 #endif