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 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
  44
  45 static struct kmem_cache *field_cachep;
  46 static struct kmem_cache *file_cachep;
  47
  48 static inline int system_refcount(struct event_subsystem *system)
  49 {
  50         return system->ref_count;
  51 }
  52
  53 static int system_refcount_inc(struct event_subsystem *system)
  54 {
  55         return system->ref_count++;
  56 }
  57
  58 static int system_refcount_dec(struct event_subsystem *system)
  59 {
  60         return --system->ref_count;
  61 }
  62
  63 /* Double loops, do not use break, only goto's work */
  64 #define do_for_each_event_file(tr, file)                        \
  65         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
  66                 list_for_each_entry(file, &tr->events, list)
  67
  68 #define do_for_each_event_file_safe(tr, file)                   \
  69         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
  70                 struct trace_event_file *___n;                          \
  71                 list_for_each_entry_safe(file, ___n, &tr->events, list)
  72
  73 #define while_for_each_event_file()             \
  74         }
  75
  76 static struct ftrace_event_field *
  77 __find_event_field(struct list_head *head, char *name)
  78 {
  79         struct ftrace_event_field *field;
  80
  81         list_for_each_entry(field, head, link) {
  82                 if (!strcmp(field->name, name))
  83                         return field;
  84         }
  85
  86         return NULL;
  87 }
  88
  89 struct ftrace_event_field *
  90 trace_find_event_field(struct trace_event_call *call, char *name)
  91 {
  92         struct ftrace_event_field *field;
  93         struct list_head *head;
  94
  95         head = trace_get_fields(call);
  96         field = __find_event_field(head, name);
  97         if (field)
  98                 return field;
  99
 100         field = __find_event_field(&ftrace_generic_fields, name);
 101         if (field)
 102                 return field;
 103
 104         return __find_event_field(&ftrace_common_fields, name);
 105 }
 106
 107 static int __trace_define_field(struct list_head *head, const char *type,
 108                                 const char *name, int offset, int size,
 109                                 int is_signed, int filter_type)
 110 {
 111         struct ftrace_event_field *field;
 112
 113         field = kmem_cache_alloc(field_cachep, GFP_TRACE);
 114         if (!field)
 115                 return -ENOMEM;
 116
 117         field->name = name;
 118         field->type = type;
 119
 120         if (filter_type == FILTER_OTHER)
 121                 field->filter_type = filter_assign_type(type);
 122         else
 123                 field->filter_type = filter_type;
 124
 125         field->offset = offset;
 126         field->size = size;
 127         field->is_signed = is_signed;
 128
 129         list_add(&field->link, head);
 130
 131         return 0;
 132 }
 133
 134 int trace_define_field(struct trace_event_call *call, const char *type,
 135                        const char *name, int offset, int size, int is_signed,
 136                        int filter_type)
 137 {
 138         struct list_head *head;
 139
 140         if (WARN_ON(!call->class))
 141                 return 0;
 142
 143         head = trace_get_fields(call);
 144         return __trace_define_field(head, type, name, offset, size,
 145                                     is_signed, filter_type);
 146 }
 147 EXPORT_SYMBOL_GPL(trace_define_field);
 148
 149 #define __generic_field(type, item, filter_type)                        \
 150         ret = __trace_define_field(&ftrace_generic_fields, #type,       \
 151                                    #item, 0, 0, is_signed_type(type),   \
 152                                    filter_type);                        \
 153         if (ret)                                                        \
 154                 return ret;
 155
 156 #define __common_field(type, item)                                      \
 157         ret = __trace_define_field(&ftrace_common_fields, #type,        \
 158                                    "common_" #item,                     \
 159                                    offsetof(typeof(ent), item),         \
 160                                    sizeof(ent.item),                    \
 161                                    is_signed_type(type), FILTER_OTHER); \
 162         if (ret)                                                        \
 163                 return ret;
 164
 165 static int trace_define_generic_fields(void)
 166 {
 167         int ret;
 168
 169         __generic_field(int, CPU, FILTER_CPU);
 170         __generic_field(int, cpu, FILTER_CPU);
 171         __generic_field(char *, COMM, FILTER_COMM);
 172         __generic_field(char *, comm, FILTER_COMM);
 173
 174         return ret;
 175 }
 176
 177 static int trace_define_common_fields(void)
 178 {
 179         int ret;
 180         struct trace_entry ent;
 181
 182         __common_field(unsigned short, type);
 183         __common_field(unsigned char, flags);
 184         /* Holds both preempt_count and migrate_disable */
 185         __common_field(unsigned char, preempt_count);
 186         __common_field(int, pid);
 187
 188         return ret;
 189 }
 190
 191 static void trace_destroy_fields(struct trace_event_call *call)
 192 {
 193         struct ftrace_event_field *field, *next;
 194         struct list_head *head;
 195
 196         head = trace_get_fields(call);
 197         list_for_each_entry_safe(field, next, head, link) {
 198                 list_del(&field->link);
 199                 kmem_cache_free(field_cachep, field);
 200         }
 201 }
 202
 203 /*
 204  * run-time version of trace_event_get_offsets_<call>() that returns the last
 205  * accessible offset of trace fields excluding __dynamic_array bytes
 206  */
 207 int trace_event_get_offsets(struct trace_event_call *call)
 208 {
 209         struct ftrace_event_field *tail;
 210         struct list_head *head;
 211
 212         head = trace_get_fields(call);
 213         /*
 214          * head->next points to the last field with the largest offset,
 215          * since it was added last by trace_define_field()
 216          */
 217         tail = list_first_entry(head, struct ftrace_event_field, link);
 218         return tail->offset + tail->size;
 219 }
 220
 221 /*
 222  * Check if the referenced field is an array and return true,
 223  * as arrays are OK to dereference.
 224  */
 225 static bool test_field(const char *fmt, struct trace_event_call *call)
 226 {
 227         struct trace_event_fields *field = call->class->fields_array;
 228         const char *array_descriptor;
 229         const char *p = fmt;
 230         int len;
 231
 232         if (!(len = str_has_prefix(fmt, "REC->")))
 233                 return false;
 234         fmt += len;
 235         for (p = fmt; *p; p++) {
 236                 if (!isalnum(*p) && *p != '_')
 237                         break;
 238         }
 239         len = p - fmt;
 240
 241         for (; field->type; field++) {
 242                 if (strncmp(field->name, fmt, len) ||
 243                     field->name[len])
 244                         continue;
 245                 array_descriptor = strchr(field->type, '[');
 246                 /* This is an array and is OK to dereference. */
 247                 return array_descriptor != NULL;
 248         }
 249         return false;
 250 }
 251
 252 /*
 253  * Examine the print fmt of the event looking for unsafe dereference
 254  * pointers using %p* that could be recorded in the trace event and
 255  * much later referenced after the pointer was freed. Dereferencing
 256  * pointers are OK, if it is dereferenced into the event itself.
 257  */
 258 static void test_event_printk(struct trace_event_call *call)
 259 {
 260         u64 dereference_flags = 0;
 261         bool first = true;
 262         const char *fmt, *c, *r, *a;
 263         int parens = 0;
 264         char in_quote = 0;
 265         int start_arg = 0;
 266         int arg = 0;
 267         int i;
 268
 269         fmt = call->print_fmt;
 270
 271         if (!fmt)
 272                 return;
 273
 274         for (i = 0; fmt[i]; i++) {
 275                 switch (fmt[i]) {
 276                 case '\\':
 277                         i++;
 278                         if (!fmt[i])
 279                                 return;
 280                         continue;
 281                 case '"':
 282                 case '\'':
 283                         /*
 284                          * The print fmt starts with a string that
 285                          * is processed first to find %p* usage,
 286                          * then after the first string, the print fmt
 287                          * contains arguments that are used to check
 288                          * if the dereferenced %p* usage is safe.
 289                          */
 290                         if (first) {
 291                                 if (fmt[i] == '\'')
 292                                         continue;
 293                                 if (in_quote) {
 294                                         arg = 0;
 295                                         first = false;
 296                                         /*
 297                                          * If there was no %p* uses
 298                                          * the fmt is OK.
 299                                          */
 300                                         if (!dereference_flags)
 301                                                 return;
 302                                 }
 303                         }
 304                         if (in_quote) {
 305                                 if (in_quote == fmt[i])
 306                                         in_quote = 0;
 307                         } else {
 308                                 in_quote = fmt[i];
 309                         }
 310                         continue;
 311                 case '%':
 312                         if (!first || !in_quote)
 313                                 continue;
 314                         i++;
 315                         if (!fmt[i])
 316                                 return;
 317                         switch (fmt[i]) {
 318                         case '%':
 319                                 continue;
 320                         case 'p':
 321                                 /* Find dereferencing fields */
 322                                 switch (fmt[i + 1]) {
 323                                 case 'B': case 'R': case 'r':
 324                                 case 'b': case 'M': case 'm':
 325                                 case 'I': case 'i': case 'E':
 326                                 case 'U': case 'V': case 'N':
 327                                 case 'a': case 'd': case 'D':
 328                                 case 'g': case 't': case 'C':
 329                                 case 'O': case 'f':
 330                                         if (WARN_ONCE(arg == 63,
 331                                                       "Too many args for event: %s",
 332                                                       trace_event_name(call)))
 333                                                 return;
 334                                         dereference_flags |= 1ULL << arg;
 335                                 }
 336                                 break;
 337                         default:
 338                         {
 339                                 bool star = false;
 340                                 int j;
 341
 342                                 /* Increment arg if %*s exists. */
 343                                 for (j = 0; fmt[i + j]; j++) {
 344                                         if (isdigit(fmt[i + j]) ||
 345                                             fmt[i + j] == '.')
 346                                                 continue;
 347                                         if (fmt[i + j] == '*') {
 348                                                 star = true;
 349                                                 continue;
 350                                         }
 351                                         if ((fmt[i + j] == 's') && star)
 352                                                 arg++;
 353                                         break;
 354                                 }
 355                                 break;
 356                         } /* default */
 357
 358                         } /* switch */
 359                         arg++;
 360                         continue;
 361                 case '(':
 362                         if (in_quote)
 363                                 continue;
 364                         parens++;
 365                         continue;
 366                 case ')':
 367                         if (in_quote)
 368                                 continue;
 369                         parens--;
 370                         if (WARN_ONCE(parens < 0,
 371                                       "Paren mismatch for event: %s\narg='%s'\n%*s",
 372                                       trace_event_name(call),
 373                                       fmt + start_arg,
 374                                       (i - start_arg) + 5, "^"))
 375                                 return;
 376                         continue;
 377                 case ',':
 378                         if (in_quote || parens)
 379                                 continue;
 380                         i++;
 381                         while (isspace(fmt[i]))
 382                                 i++;
 383                         start_arg = i;
 384                         if (!(dereference_flags & (1ULL << arg)))
 385                                 goto next_arg;
 386
 387                         /* Find the REC-> in the argument */
 388                         c = strchr(fmt + i, ',');
 389                         r = strstr(fmt + i, "REC->");
 390                         if (r && (!c || r < c)) {
 391                                 /*
 392                                  * Addresses of events on the buffer,
 393                                  * or an array on the buffer is
 394                                  * OK to dereference.
 395                                  * There's ways to fool this, but
 396                                  * this is to catch common mistakes,
 397                                  * not malicious code.
 398                                  */
 399                                 a = strchr(fmt + i, '&');
 400                                 if ((a && (a < r)) || test_field(r, call))
 401                                         dereference_flags &= ~(1ULL << arg);
 402                         }
 403                 next_arg:
 404                         i--;
 405                         arg++;
 406                 }
 407         }
 408
 409         /*
 410          * If you triggered the below warning, the trace event reported
 411          * uses an unsafe dereference pointer %p*. As the data stored
 412          * at the trace event time may no longer exist when the trace
 413          * event is printed, dereferencing to the original source is
 414          * unsafe. The source of the dereference must be copied into the
 415          * event itself, and the dereference must access the copy instead.
 416          */
 417         if (WARN_ON_ONCE(dereference_flags)) {
 418                 arg = 1;
 419                 while (!(dereference_flags & 1)) {
 420                         dereference_flags >>= 1;
 421                         arg++;
 422                 }
 423                 pr_warn("event %s has unsafe dereference of argument %d\n",
 424                         trace_event_name(call), arg);
 425                 pr_warn("print_fmt: %s\n", fmt);
 426         }
 427 }
 428
 429 int trace_event_raw_init(struct trace_event_call *call)
 430 {
 431         int id;
 432
 433         id = register_trace_event(&call->event);
 434         if (!id)
 435                 return -ENODEV;
 436
 437         test_event_printk(call);
 438
 439         return 0;
 440 }
 441 EXPORT_SYMBOL_GPL(trace_event_raw_init);
 442
 443 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
 444 {
 445         struct trace_array *tr = trace_file->tr;
 446         struct trace_array_cpu *data;
 447         struct trace_pid_list *no_pid_list;
 448         struct trace_pid_list *pid_list;
 449
 450         pid_list = rcu_dereference_raw(tr->filtered_pids);
 451         no_pid_list = rcu_dereference_raw(tr->filtered_no_pids);
 452
 453         if (!pid_list && !no_pid_list)
 454                 return false;
 455
 456         data = this_cpu_ptr(tr->array_buffer.data);
 457
 458         return data->ignore_pid;
 459 }
 460 EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
 461
 462 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 463                                  struct trace_event_file *trace_file,
 464                                  unsigned long len)
 465 {
 466         struct trace_event_call *event_call = trace_file->event_call;
 467
 468         if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
 469             trace_event_ignore_this_pid(trace_file))
 470                 return NULL;
 471
 472         /*
 473          * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
 474          * preemption (adding one to the preempt_count). Since we are
 475          * interested in the preempt_count at the time the tracepoint was
 476          * hit, we need to subtract one to offset the increment.
 477          */
 478         fbuffer->trace_ctx = tracing_gen_ctx_dec();
 479         fbuffer->trace_file = trace_file;
 480
 481         fbuffer->event =
 482                 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
 483                                                 event_call->event.type, len,
 484                                                 fbuffer->trace_ctx);
 485         if (!fbuffer->event)
 486                 return NULL;
 487
 488         fbuffer->regs = NULL;
 489         fbuffer->entry = ring_buffer_event_data(fbuffer->event);
 490         return fbuffer->entry;
 491 }
 492 EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
 493
 494 int trace_event_reg(struct trace_event_call *call,
 495                     enum trace_reg type, void *data)
 496 {
 497         struct trace_event_file *file = data;
 498
 499         WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
 500         switch (type) {
 501         case TRACE_REG_REGISTER:
 502                 return tracepoint_probe_register(call->tp,
 503                                                  call->class->probe,
 504                                                  file);
 505         case TRACE_REG_UNREGISTER:
 506                 tracepoint_probe_unregister(call->tp,
 507                                             call->class->probe,
 508                                             file);
 509                 return 0;
 510
 511 #ifdef CONFIG_PERF_EVENTS
 512         case TRACE_REG_PERF_REGISTER:
 513                 return tracepoint_probe_register(call->tp,
 514                                                  call->class->perf_probe,
 515                                                  call);
 516         case TRACE_REG_PERF_UNREGISTER:
 517                 tracepoint_probe_unregister(call->tp,
 518                                             call->class->perf_probe,
 519                                             call);
 520                 return 0;
 521         case TRACE_REG_PERF_OPEN:
 522         case TRACE_REG_PERF_CLOSE:
 523         case TRACE_REG_PERF_ADD:
 524         case TRACE_REG_PERF_DEL:
 525                 return 0;
 526 #endif
 527         }
 528         return 0;
 529 }
 530 EXPORT_SYMBOL_GPL(trace_event_reg);
 531
 532 void trace_event_enable_cmd_record(bool enable)
 533 {
 534         struct trace_event_file *file;
 535         struct trace_array *tr;
 536
 537         lockdep_assert_held(&event_mutex);
 538
 539         do_for_each_event_file(tr, file) {
 540
 541                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
 542                         continue;
 543
 544                 if (enable) {
 545                         tracing_start_cmdline_record();
 546                         set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 547                 } else {
 548                         tracing_stop_cmdline_record();
 549                         clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 550                 }
 551         } while_for_each_event_file();
 552 }
 553
 554 void trace_event_enable_tgid_record(bool enable)
 555 {
 556         struct trace_event_file *file;
 557         struct trace_array *tr;
 558
 559         lockdep_assert_held(&event_mutex);
 560
 561         do_for_each_event_file(tr, file) {
 562                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
 563                         continue;
 564
 565                 if (enable) {
 566                         tracing_start_tgid_record();
 567                         set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 568                 } else {
 569                         tracing_stop_tgid_record();
 570                         clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
 571                                   &file->flags);
 572                 }
 573         } while_for_each_event_file();
 574 }
 575
 576 static int __ftrace_event_enable_disable(struct trace_event_file *file,
 577                                          int enable, int soft_disable)
 578 {
 579         struct trace_event_call *call = file->event_call;
 580         struct trace_array *tr = file->tr;
 581         unsigned long file_flags = file->flags;
 582         int ret = 0;
 583         int disable;
 584
 585         switch (enable) {
 586         case 0:
 587                 /*
 588                  * When soft_disable is set and enable is cleared, the sm_ref
 589                  * reference counter is decremented. If it reaches 0, we want
 590                  * to clear the SOFT_DISABLED flag but leave the event in the
 591                  * state that it was. That is, if the event was enabled and
 592                  * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
 593                  * is set we do not want the event to be enabled before we
 594                  * clear the bit.
 595                  *
 596                  * When soft_disable is not set but the SOFT_MODE flag is,
 597                  * we do nothing. Do not disable the tracepoint, otherwise
 598                  * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
 599                  */
 600                 if (soft_disable) {
 601                         if (atomic_dec_return(&file->sm_ref) > 0)
 602                                 break;
 603                         disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
 604                         clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 605                 } else
 606                         disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
 607
 608                 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
 609                         clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 610                         if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
 611                                 tracing_stop_cmdline_record();
 612                                 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 613                         }
 614
 615                         if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
 616                                 tracing_stop_tgid_record();
 617                                 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 618                         }
 619
 620                         call->class->reg(call, TRACE_REG_UNREGISTER, file);
 621                 }
 622                 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
 623                 if (file->flags & EVENT_FILE_FL_SOFT_MODE)
 624                         set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 625                 else
 626                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 627                 break;
 628         case 1:
 629                 /*
 630                  * When soft_disable is set and enable is set, we want to
 631                  * register the tracepoint for the event, but leave the event
 632                  * as is. That means, if the event was already enabled, we do
 633                  * nothing (but set SOFT_MODE). If the event is disabled, we
 634                  * set SOFT_DISABLED before enabling the event tracepoint, so
 635                  * it still seems to be disabled.
 636                  */
 637                 if (!soft_disable)
 638                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 639                 else {
 640                         if (atomic_inc_return(&file->sm_ref) > 1)
 641                                 break;
 642                         set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 643                 }
 644
 645                 if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
 646                         bool cmd = false, tgid = false;
 647
 648                         /* Keep the event disabled, when going to SOFT_MODE. */
 649                         if (soft_disable)
 650                                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 651
 652                         if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
 653                                 cmd = true;
 654                                 tracing_start_cmdline_record();
 655                                 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 656                         }
 657
 658                         if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
 659                                 tgid = true;
 660                                 tracing_start_tgid_record();
 661                                 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 662                         }
 663
 664                         ret = call->class->reg(call, TRACE_REG_REGISTER, file);
 665                         if (ret) {
 666                                 if (cmd)
 667                                         tracing_stop_cmdline_record();
 668                                 if (tgid)
 669                                         tracing_stop_tgid_record();
 670                                 pr_info("event trace: Could not enable event "
 671                                         "%s\n", trace_event_name(call));
 672                                 break;
 673                         }
 674                         set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 675
 676                         /* WAS_ENABLED gets set but never cleared. */
 677                         set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
 678                 }
 679                 break;
 680         }
 681
 682         /* Enable or disable use of trace_buffered_event */
 683         if ((file_flags & EVENT_FILE_FL_SOFT_DISABLED) !=
 684             (file->flags & EVENT_FILE_FL_SOFT_DISABLED)) {
 685                 if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
 686                         trace_buffered_event_enable();
 687                 else
 688                         trace_buffered_event_disable();
 689         }
 690
 691         return ret;
 692 }
 693
 694 int trace_event_enable_disable(struct trace_event_file *file,
 695                                int enable, int soft_disable)
 696 {
 697         return __ftrace_event_enable_disable(file, enable, soft_disable);
 698 }
 699
 700 static int ftrace_event_enable_disable(struct trace_event_file *file,
 701                                        int enable)
 702 {
 703         return __ftrace_event_enable_disable(file, enable, 0);
 704 }
 705
 706 static void ftrace_clear_events(struct trace_array *tr)
 707 {
 708         struct trace_event_file *file;
 709
 710         mutex_lock(&event_mutex);
 711         list_for_each_entry(file, &tr->events, list) {
 712                 ftrace_event_enable_disable(file, 0);
 713         }
 714         mutex_unlock(&event_mutex);
 715 }
 716
 717 static void
 718 event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
 719 {
 720         struct trace_pid_list *pid_list;
 721         struct trace_array *tr = data;
 722
 723         pid_list = rcu_dereference_raw(tr->filtered_pids);
 724         trace_filter_add_remove_task(pid_list, NULL, task);
 725
 726         pid_list = rcu_dereference_raw(tr->filtered_no_pids);
 727         trace_filter_add_remove_task(pid_list, NULL, task);
 728 }
 729
 730 static void
 731 event_filter_pid_sched_process_fork(void *data,
 732                                     struct task_struct *self,
 733                                     struct task_struct *task)
 734 {
 735         struct trace_pid_list *pid_list;
 736         struct trace_array *tr = data;
 737
 738         pid_list = rcu_dereference_sched(tr->filtered_pids);
 739         trace_filter_add_remove_task(pid_list, self, task);
 740
 741         pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 742         trace_filter_add_remove_task(pid_list, self, task);
 743 }
 744
 745 void trace_event_follow_fork(struct trace_array *tr, bool enable)
 746 {
 747         if (enable) {
 748                 register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
 749                                                        tr, INT_MIN);
 750                 register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
 751                                                        tr, INT_MAX);
 752         } else {
 753                 unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
 754                                                     tr);
 755                 unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
 756                                                     tr);
 757         }
 758 }
 759
 760 static void
 761 event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
 762                     struct task_struct *prev, struct task_struct *next)
 763 {
 764         struct trace_array *tr = data;
 765         struct trace_pid_list *no_pid_list;
 766         struct trace_pid_list *pid_list;
 767         bool ret;
 768
 769         pid_list = rcu_dereference_sched(tr->filtered_pids);
 770         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 771
 772         /*
 773          * Sched switch is funny, as we only want to ignore it
 774          * in the notrace case if both prev and next should be ignored.
 775          */
 776         ret = trace_ignore_this_task(NULL, no_pid_list, prev) &&
 777                 trace_ignore_this_task(NULL, no_pid_list, next);
 778
 779         this_cpu_write(tr->array_buffer.data->ignore_pid, ret ||
 780                        (trace_ignore_this_task(pid_list, NULL, prev) &&
 781                         trace_ignore_this_task(pid_list, NULL, next)));
 782 }
 783
 784 static void
 785 event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
 786                     struct task_struct *prev, struct task_struct *next)
 787 {
 788         struct trace_array *tr = data;
 789         struct trace_pid_list *no_pid_list;
 790         struct trace_pid_list *pid_list;
 791
 792         pid_list = rcu_dereference_sched(tr->filtered_pids);
 793         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 794
 795         this_cpu_write(tr->array_buffer.data->ignore_pid,
 796                        trace_ignore_this_task(pid_list, no_pid_list, next));
 797 }
 798
 799 static void
 800 event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
 801 {
 802         struct trace_array *tr = data;
 803         struct trace_pid_list *no_pid_list;
 804         struct trace_pid_list *pid_list;
 805
 806         /* Nothing to do if we are already tracing */
 807         if (!this_cpu_read(tr->array_buffer.data->ignore_pid))
 808                 return;
 809
 810         pid_list = rcu_dereference_sched(tr->filtered_pids);
 811         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 812
 813         this_cpu_write(tr->array_buffer.data->ignore_pid,
 814                        trace_ignore_this_task(pid_list, no_pid_list, task));
 815 }
 816
 817 static void
 818 event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
 819 {
 820         struct trace_array *tr = data;
 821         struct trace_pid_list *no_pid_list;
 822         struct trace_pid_list *pid_list;
 823
 824         /* Nothing to do if we are not tracing */
 825         if (this_cpu_read(tr->array_buffer.data->ignore_pid))
 826                 return;
 827
 828         pid_list = rcu_dereference_sched(tr->filtered_pids);
 829         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 830
 831         /* Set tracing if current is enabled */
 832         this_cpu_write(tr->array_buffer.data->ignore_pid,
 833                        trace_ignore_this_task(pid_list, no_pid_list, current));
 834 }
 835
 836 static void unregister_pid_events(struct trace_array *tr)
 837 {
 838         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
 839         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
 840
 841         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
 842         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
 843
 844         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
 845         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
 846
 847         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
 848         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
 849 }
 850
 851 static void __ftrace_clear_event_pids(struct trace_array *tr, int type)
 852 {
 853         struct trace_pid_list *pid_list;
 854         struct trace_pid_list *no_pid_list;
 855         struct trace_event_file *file;
 856         int cpu;
 857
 858         pid_list = rcu_dereference_protected(tr->filtered_pids,
 859                                              lockdep_is_held(&event_mutex));
 860         no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
 861                                              lockdep_is_held(&event_mutex));
 862
 863         /* Make sure there's something to do */
 864         if (!pid_type_enabled(type, pid_list, no_pid_list))
 865                 return;
 866
 867         if (!still_need_pid_events(type, pid_list, no_pid_list)) {
 868                 unregister_pid_events(tr);
 869
 870                 list_for_each_entry(file, &tr->events, list) {
 871                         clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
 872                 }
 873
 874                 for_each_possible_cpu(cpu)
 875                         per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
 876         }
 877
 878         if (type & TRACE_PIDS)
 879                 rcu_assign_pointer(tr->filtered_pids, NULL);
 880
 881         if (type & TRACE_NO_PIDS)
 882                 rcu_assign_pointer(tr->filtered_no_pids, NULL);
 883
 884         /* Wait till all users are no longer using pid filtering */
 885         tracepoint_synchronize_unregister();
 886
 887         if ((type & TRACE_PIDS) && pid_list)
 888                 trace_free_pid_list(pid_list);
 889
 890         if ((type & TRACE_NO_PIDS) && no_pid_list)
 891                 trace_free_pid_list(no_pid_list);
 892 }
 893
 894 static void ftrace_clear_event_pids(struct trace_array *tr, int type)
 895 {
 896         mutex_lock(&event_mutex);
 897         __ftrace_clear_event_pids(tr, type);
 898         mutex_unlock(&event_mutex);
 899 }
 900
 901 static void __put_system(struct event_subsystem *system)
 902 {
 903         struct event_filter *filter = system->filter;
 904
 905         WARN_ON_ONCE(system_refcount(system) == 0);
 906         if (system_refcount_dec(system))
 907                 return;
 908
 909         list_del(&system->list);
 910
 911         if (filter) {
 912                 kfree(filter->filter_string);
 913                 kfree(filter);
 914         }
 915         kfree_const(system->name);
 916         kfree(system);
 917 }
 918
 919 static void __get_system(struct event_subsystem *system)
 920 {
 921         WARN_ON_ONCE(system_refcount(system) == 0);
 922         system_refcount_inc(system);
 923 }
 924
 925 static void __get_system_dir(struct trace_subsystem_dir *dir)
 926 {
 927         WARN_ON_ONCE(dir->ref_count == 0);
 928         dir->ref_count++;
 929         __get_system(dir->subsystem);
 930 }
 931
 932 static void __put_system_dir(struct trace_subsystem_dir *dir)
 933 {
 934         WARN_ON_ONCE(dir->ref_count == 0);
 935         /* If the subsystem is about to be freed, the dir must be too */
 936         WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
 937
 938         __put_system(dir->subsystem);
 939         if (!--dir->ref_count)
 940                 kfree(dir);
 941 }
 942
 943 static void put_system(struct trace_subsystem_dir *dir)
 944 {
 945         mutex_lock(&event_mutex);
 946         __put_system_dir(dir);
 947         mutex_unlock(&event_mutex);
 948 }
 949
 950 static void remove_subsystem(struct trace_subsystem_dir *dir)
 951 {
 952         if (!dir)
 953                 return;
 954
 955         if (!--dir->nr_events) {
 956                 tracefs_remove(dir->entry);
 957                 list_del(&dir->list);
 958                 __put_system_dir(dir);
 959         }
 960 }
 961
 962 static void remove_event_file_dir(struct trace_event_file *file)
 963 {
 964         struct dentry *dir = file->dir;
 965         struct dentry *child;
 966
 967         if (dir) {
 968                 spin_lock(&dir->d_lock);        /* probably unneeded */
 969                 list_for_each_entry(child, &dir->d_subdirs, d_child) {
 970                         if (d_really_is_positive(child))        /* probably unneeded */
 971                                 d_inode(child)->i_private = NULL;
 972                 }
 973                 spin_unlock(&dir->d_lock);
 974
 975                 tracefs_remove(dir);
 976         }
 977
 978         list_del(&file->list);
 979         remove_subsystem(file->system);
 980         free_event_filter(file->filter);
 981         kmem_cache_free(file_cachep, file);
 982 }
 983
 984 /*
 985  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
 986  */
 987 static int
 988 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
 989                               const char *sub, const char *event, int set)
 990 {
 991         struct trace_event_file *file;
 992         struct trace_event_call *call;
 993         const char *name;
 994         int ret = -EINVAL;
 995         int eret = 0;
 996
 997         list_for_each_entry(file, &tr->events, list) {
 998
 999                 call = file->event_call;
1000                 name = trace_event_name(call);
1001
1002                 if (!name || !call->class || !call->class->reg)
1003                         continue;
1004
1005                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1006                         continue;
1007
1008                 if (match &&
1009                     strcmp(match, name) != 0 &&
1010                     strcmp(match, call->class->system) != 0)
1011                         continue;
1012
1013                 if (sub && strcmp(sub, call->class->system) != 0)
1014                         continue;
1015
1016                 if (event && strcmp(event, name) != 0)
1017                         continue;
1018
1019                 ret = ftrace_event_enable_disable(file, set);
1020
1021                 /*
1022                  * Save the first error and return that. Some events
1023                  * may still have been enabled, but let the user
1024                  * know that something went wrong.
1025                  */
1026                 if (ret && !eret)
1027                         eret = ret;
1028
1029                 ret = eret;
1030         }
1031
1032         return ret;
1033 }
1034
1035 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
1036                                   const char *sub, const char *event, int set)
1037 {
1038         int ret;
1039
1040         mutex_lock(&event_mutex);
1041         ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
1042         mutex_unlock(&event_mutex);
1043
1044         return ret;
1045 }
1046
1047 int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
1048 {
1049         char *event = NULL, *sub = NULL, *match;
1050         int ret;
1051
1052         if (!tr)
1053                 return -ENOENT;
1054         /*
1055          * The buf format can be <subsystem>:<event-name>
1056          *  *:<event-name> means any event by that name.
1057          *  :<event-name> is the same.
1058          *
1059          *  <subsystem>:* means all events in that subsystem
1060          *  <subsystem>: means the same.
1061          *
1062          *  <name> (no ':') means all events in a subsystem with
1063          *  the name <name> or any event that matches <name>
1064          */
1065
1066         match = strsep(&buf, ":");
1067         if (buf) {
1068                 sub = match;
1069                 event = buf;
1070                 match = NULL;
1071
1072                 if (!strlen(sub) || strcmp(sub, "*") == 0)
1073                         sub = NULL;
1074                 if (!strlen(event) || strcmp(event, "*") == 0)
1075                         event = NULL;
1076         }
1077
1078         ret = __ftrace_set_clr_event(tr, match, sub, event, set);
1079
1080         /* Put back the colon to allow this to be called again */
1081         if (buf)
1082                 *(buf - 1) = ':';
1083
1084         return ret;
1085 }
1086
1087 /**
1088  * trace_set_clr_event - enable or disable an event
1089  * @system: system name to match (NULL for any system)
1090  * @event: event name to match (NULL for all events, within system)
1091  * @set: 1 to enable, 0 to disable
1092  *
1093  * This is a way for other parts of the kernel to enable or disable
1094  * event recording.
1095  *
1096  * Returns 0 on success, -EINVAL if the parameters do not match any
1097  * registered events.
1098  */
1099 int trace_set_clr_event(const char *system, const char *event, int set)
1100 {
1101         struct trace_array *tr = top_trace_array();
1102
1103         if (!tr)
1104                 return -ENODEV;
1105
1106         return __ftrace_set_clr_event(tr, NULL, system, event, set);
1107 }
1108 EXPORT_SYMBOL_GPL(trace_set_clr_event);
1109
1110 /**
1111  * trace_array_set_clr_event - enable or disable an event for a trace array.
1112  * @tr: concerned trace array.
1113  * @system: system name to match (NULL for any system)
1114  * @event: event name to match (NULL for all events, within system)
1115  * @enable: true to enable, false to disable
1116  *
1117  * This is a way for other parts of the kernel to enable or disable
1118  * event recording.
1119  *
1120  * Returns 0 on success, -EINVAL if the parameters do not match any
1121  * registered events.
1122  */
1123 int trace_array_set_clr_event(struct trace_array *tr, const char *system,
1124                 const char *event, bool enable)
1125 {
1126         int set;
1127
1128         if (!tr)
1129                 return -ENOENT;
1130
1131         set = (enable == true) ? 1 : 0;
1132         return __ftrace_set_clr_event(tr, NULL, system, event, set);
1133 }
1134 EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
1135
1136 /* 128 should be much more than enough */
1137 #define EVENT_BUF_SIZE          127
1138
1139 static ssize_t
1140 ftrace_event_write(struct file *file, const char __user *ubuf,
1141                    size_t cnt, loff_t *ppos)
1142 {
1143         struct trace_parser parser;
1144         struct seq_file *m = file->private_data;
1145         struct trace_array *tr = m->private;
1146         ssize_t read, ret;
1147
1148         if (!cnt)
1149                 return 0;
1150
1151         ret = tracing_update_buffers();
1152         if (ret < 0)
1153                 return ret;
1154
1155         if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
1156                 return -ENOMEM;
1157
1158         read = trace_get_user(&parser, ubuf, cnt, ppos);
1159
1160         if (read >= 0 && trace_parser_loaded((&parser))) {
1161                 int set = 1;
1162
1163                 if (*parser.buffer == '!')
1164                         set = 0;
1165
1166                 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
1167                 if (ret)
1168                         goto out_put;
1169         }
1170
1171         ret = read;
1172
1173  out_put:
1174         trace_parser_put(&parser);
1175
1176         return ret;
1177 }
1178
1179 static void *
1180 t_next(struct seq_file *m, void *v, loff_t *pos)
1181 {
1182         struct trace_event_file *file = v;
1183         struct trace_event_call *call;
1184         struct trace_array *tr = m->private;
1185
1186         (*pos)++;
1187
1188         list_for_each_entry_continue(file, &tr->events, list) {
1189                 call = file->event_call;
1190                 /*
1191                  * The ftrace subsystem is for showing formats only.
1192                  * They can not be enabled or disabled via the event files.
1193                  */
1194                 if (call->class && call->class->reg &&
1195                     !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1196                         return file;
1197         }
1198
1199         return NULL;
1200 }
1201
1202 static void *t_start(struct seq_file *m, loff_t *pos)
1203 {
1204         struct trace_event_file *file;
1205         struct trace_array *tr = m->private;
1206         loff_t l;
1207
1208         mutex_lock(&event_mutex);
1209
1210         file = list_entry(&tr->events, struct trace_event_file, list);
1211         for (l = 0; l <= *pos; ) {
1212                 file = t_next(m, file, &l);
1213                 if (!file)
1214                         break;
1215         }
1216         return file;
1217 }
1218
1219 static void *
1220 s_next(struct seq_file *m, void *v, loff_t *pos)
1221 {
1222         struct trace_event_file *file = v;
1223         struct trace_array *tr = m->private;
1224
1225         (*pos)++;
1226
1227         list_for_each_entry_continue(file, &tr->events, list) {
1228                 if (file->flags & EVENT_FILE_FL_ENABLED)
1229                         return file;
1230         }
1231
1232         return NULL;
1233 }
1234
1235 static void *s_start(struct seq_file *m, loff_t *pos)
1236 {
1237         struct trace_event_file *file;
1238         struct trace_array *tr = m->private;
1239         loff_t l;
1240
1241         mutex_lock(&event_mutex);
1242
1243         file = list_entry(&tr->events, struct trace_event_file, list);
1244         for (l = 0; l <= *pos; ) {
1245                 file = s_next(m, file, &l);
1246                 if (!file)
1247                         break;
1248         }
1249         return file;
1250 }
1251
1252 static int t_show(struct seq_file *m, void *v)
1253 {
1254         struct trace_event_file *file = v;
1255         struct trace_event_call *call = file->event_call;
1256
1257         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1258                 seq_printf(m, "%s:", call->class->system);
1259         seq_printf(m, "%s\n", trace_event_name(call));
1260
1261         return 0;
1262 }
1263
1264 static void t_stop(struct seq_file *m, void *p)
1265 {
1266         mutex_unlock(&event_mutex);
1267 }
1268
1269 static void *
1270 __next(struct seq_file *m, void *v, loff_t *pos, int type)
1271 {
1272         struct trace_array *tr = m->private;
1273         struct trace_pid_list *pid_list;
1274
1275         if (type == TRACE_PIDS)
1276                 pid_list = rcu_dereference_sched(tr->filtered_pids);
1277         else
1278                 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1279
1280         return trace_pid_next(pid_list, v, pos);
1281 }
1282
1283 static void *
1284 p_next(struct seq_file *m, void *v, loff_t *pos)
1285 {
1286         return __next(m, v, pos, TRACE_PIDS);
1287 }
1288
1289 static void *
1290 np_next(struct seq_file *m, void *v, loff_t *pos)
1291 {
1292         return __next(m, v, pos, TRACE_NO_PIDS);
1293 }
1294
1295 static void *__start(struct seq_file *m, loff_t *pos, int type)
1296         __acquires(RCU)
1297 {
1298         struct trace_pid_list *pid_list;
1299         struct trace_array *tr = m->private;
1300
1301         /*
1302          * Grab the mutex, to keep calls to p_next() having the same
1303          * tr->filtered_pids as p_start() has.
1304          * If we just passed the tr->filtered_pids around, then RCU would
1305          * have been enough, but doing that makes things more complex.
1306          */
1307         mutex_lock(&event_mutex);
1308         rcu_read_lock_sched();
1309
1310         if (type == TRACE_PIDS)
1311                 pid_list = rcu_dereference_sched(tr->filtered_pids);
1312         else
1313                 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1314
1315         if (!pid_list)
1316                 return NULL;
1317
1318         return trace_pid_start(pid_list, pos);
1319 }
1320
1321 static void *p_start(struct seq_file *m, loff_t *pos)
1322         __acquires(RCU)
1323 {
1324         return __start(m, pos, TRACE_PIDS);
1325 }
1326
1327 static void *np_start(struct seq_file *m, loff_t *pos)
1328         __acquires(RCU)
1329 {
1330         return __start(m, pos, TRACE_NO_PIDS);
1331 }
1332
1333 static void p_stop(struct seq_file *m, void *p)
1334         __releases(RCU)
1335 {
1336         rcu_read_unlock_sched();
1337         mutex_unlock(&event_mutex);
1338 }
1339
1340 static ssize_t
1341 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1342                   loff_t *ppos)
1343 {
1344         struct trace_event_file *file;
1345         unsigned long flags;
1346         char buf[4] = "0";
1347
1348         mutex_lock(&event_mutex);
1349         file = event_file_data(filp);
1350         if (likely(file))
1351                 flags = file->flags;
1352         mutex_unlock(&event_mutex);
1353
1354         if (!file)
1355                 return -ENODEV;
1356
1357         if (flags & EVENT_FILE_FL_ENABLED &&
1358             !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1359                 strcpy(buf, "1");
1360
1361         if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1362             flags & EVENT_FILE_FL_SOFT_MODE)
1363                 strcat(buf, "*");
1364
1365         strcat(buf, "\n");
1366
1367         return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1368 }
1369
1370 static ssize_t
1371 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1372                    loff_t *ppos)
1373 {
1374         struct trace_event_file *file;
1375         unsigned long val;
1376         int ret;
1377
1378         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1379         if (ret)
1380                 return ret;
1381
1382         ret = tracing_update_buffers();
1383         if (ret < 0)
1384                 return ret;
1385
1386         switch (val) {
1387         case 0:
1388         case 1:
1389                 ret = -ENODEV;
1390                 mutex_lock(&event_mutex);
1391                 file = event_file_data(filp);
1392                 if (likely(file))
1393                         ret = ftrace_event_enable_disable(file, val);
1394                 mutex_unlock(&event_mutex);
1395                 break;
1396
1397         default:
1398                 return -EINVAL;
1399         }
1400
1401         *ppos += cnt;
1402
1403         return ret ? ret : cnt;
1404 }
1405
1406 static ssize_t
1407 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1408                    loff_t *ppos)
1409 {
1410         const char set_to_char[4] = { '?', '0', '1', 'X' };
1411         struct trace_subsystem_dir *dir = filp->private_data;
1412         struct event_subsystem *system = dir->subsystem;
1413         struct trace_event_call *call;
1414         struct trace_event_file *file;
1415         struct trace_array *tr = dir->tr;
1416         char buf[2];
1417         int set = 0;
1418         int ret;
1419
1420         mutex_lock(&event_mutex);
1421         list_for_each_entry(file, &tr->events, list) {
1422                 call = file->event_call;
1423                 if ((call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
1424                     !trace_event_name(call) || !call->class || !call->class->reg)
1425                         continue;
1426
1427                 if (system && strcmp(call->class->system, system->name) != 0)
1428                         continue;
1429
1430                 /*
1431                  * We need to find out if all the events are set
1432                  * or if all events or cleared, or if we have
1433                  * a mixture.
1434                  */
1435                 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1436
1437                 /*
1438                  * If we have a mixture, no need to look further.
1439                  */
1440                 if (set == 3)
1441                         break;
1442         }
1443         mutex_unlock(&event_mutex);
1444
1445         buf[0] = set_to_char[set];
1446         buf[1] = '\n';
1447
1448         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1449
1450         return ret;
1451 }
1452
1453 static ssize_t
1454 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1455                     loff_t *ppos)
1456 {
1457         struct trace_subsystem_dir *dir = filp->private_data;
1458         struct event_subsystem *system = dir->subsystem;
1459         const char *name = NULL;
1460         unsigned long val;
1461         ssize_t ret;
1462
1463         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1464         if (ret)
1465                 return ret;
1466
1467         ret = tracing_update_buffers();
1468         if (ret < 0)
1469                 return ret;
1470
1471         if (val != 0 && val != 1)
1472                 return -EINVAL;
1473
1474         /*
1475          * Opening of "enable" adds a ref count to system,
1476          * so the name is safe to use.
1477          */
1478         if (system)
1479                 name = system->name;
1480
1481         ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1482         if (ret)
1483                 goto out;
1484
1485         ret = cnt;
1486
1487 out:
1488         *ppos += cnt;
1489
1490         return ret;
1491 }
1492
1493 enum {
1494         FORMAT_HEADER           = 1,
1495         FORMAT_FIELD_SEPERATOR  = 2,
1496         FORMAT_PRINTFMT         = 3,
1497 };
1498
1499 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1500 {
1501         struct trace_event_call *call = event_file_data(m->private);
1502         struct list_head *common_head = &ftrace_common_fields;
1503         struct list_head *head = trace_get_fields(call);
1504         struct list_head *node = v;
1505
1506         (*pos)++;
1507
1508         switch ((unsigned long)v) {
1509         case FORMAT_HEADER:
1510                 node = common_head;
1511                 break;
1512
1513         case FORMAT_FIELD_SEPERATOR:
1514                 node = head;
1515                 break;
1516
1517         case FORMAT_PRINTFMT:
1518                 /* all done */
1519                 return NULL;
1520         }
1521
1522         node = node->prev;
1523         if (node == common_head)
1524                 return (void *)FORMAT_FIELD_SEPERATOR;
1525         else if (node == head)
1526                 return (void *)FORMAT_PRINTFMT;
1527         else
1528                 return node;
1529 }
1530
1531 static int f_show(struct seq_file *m, void *v)
1532 {
1533         struct trace_event_call *call = event_file_data(m->private);
1534         struct ftrace_event_field *field;
1535         const char *array_descriptor;
1536
1537         switch ((unsigned long)v) {
1538         case FORMAT_HEADER:
1539                 seq_printf(m, "name: %s\n", trace_event_name(call));
1540                 seq_printf(m, "ID: %d\n", call->event.type);
1541                 seq_puts(m, "format:\n");
1542                 return 0;
1543
1544         case FORMAT_FIELD_SEPERATOR:
1545                 seq_putc(m, '\n');
1546                 return 0;
1547
1548         case FORMAT_PRINTFMT:
1549                 seq_printf(m, "\nprint fmt: %s\n",
1550                            call->print_fmt);
1551                 return 0;
1552         }
1553
1554         field = list_entry(v, struct ftrace_event_field, link);
1555         /*
1556          * Smartly shows the array type(except dynamic array).
1557          * Normal:
1558          *      field:TYPE VAR
1559          * If TYPE := TYPE[LEN], it is shown:
1560          *      field:TYPE VAR[LEN]
1561          */
1562         array_descriptor = strchr(field->type, '[');
1563
1564         if (str_has_prefix(field->type, "__data_loc"))
1565                 array_descriptor = NULL;
1566
1567         if (!array_descriptor)
1568                 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1569                            field->type, field->name, field->offset,
1570                            field->size, !!field->is_signed);
1571         else
1572                 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1573                            (int)(array_descriptor - field->type),
1574                            field->type, field->name,
1575                            array_descriptor, field->offset,
1576                            field->size, !!field->is_signed);
1577
1578         return 0;
1579 }
1580
1581 static void *f_start(struct seq_file *m, loff_t *pos)
1582 {
1583         void *p = (void *)FORMAT_HEADER;
1584         loff_t l = 0;
1585
1586         /* ->stop() is called even if ->start() fails */
1587         mutex_lock(&event_mutex);
1588         if (!event_file_data(m->private))
1589                 return ERR_PTR(-ENODEV);
1590
1591         while (l < *pos && p)
1592                 p = f_next(m, p, &l);
1593
1594         return p;
1595 }
1596
1597 static void f_stop(struct seq_file *m, void *p)
1598 {
1599         mutex_unlock(&event_mutex);
1600 }
1601
1602 static const struct seq_operations trace_format_seq_ops = {
1603         .start          = f_start,
1604         .next           = f_next,
1605         .stop           = f_stop,
1606         .show           = f_show,
1607 };
1608
1609 static int trace_format_open(struct inode *inode, struct file *file)
1610 {
1611         struct seq_file *m;
1612         int ret;
1613
1614         /* Do we want to hide event format files on tracefs lockdown? */
1615
1616         ret = seq_open(file, &trace_format_seq_ops);
1617         if (ret < 0)
1618                 return ret;
1619
1620         m = file->private_data;
1621         m->private = file;
1622
1623         return 0;
1624 }
1625
1626 static ssize_t
1627 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1628 {
1629         int id = (long)event_file_data(filp);
1630         char buf[32];
1631         int len;
1632
1633         if (unlikely(!id))
1634                 return -ENODEV;
1635
1636         len = sprintf(buf, "%d\n", id);
1637
1638         return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1639 }
1640
1641 static ssize_t
1642 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1643                   loff_t *ppos)
1644 {
1645         struct trace_event_file *file;
1646         struct trace_seq *s;
1647         int r = -ENODEV;
1648
1649         if (*ppos)
1650                 return 0;
1651
1652         s = kmalloc(sizeof(*s), GFP_KERNEL);
1653
1654         if (!s)
1655                 return -ENOMEM;
1656
1657         trace_seq_init(s);
1658
1659         mutex_lock(&event_mutex);
1660         file = event_file_data(filp);
1661         if (file)
1662                 print_event_filter(file, s);
1663         mutex_unlock(&event_mutex);
1664
1665         if (file)
1666                 r = simple_read_from_buffer(ubuf, cnt, ppos,
1667                                             s->buffer, trace_seq_used(s));
1668
1669         kfree(s);
1670
1671         return r;
1672 }
1673
1674 static ssize_t
1675 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1676                    loff_t *ppos)
1677 {
1678         struct trace_event_file *file;
1679         char *buf;
1680         int err = -ENODEV;
1681
1682         if (cnt >= PAGE_SIZE)
1683                 return -EINVAL;
1684
1685         buf = memdup_user_nul(ubuf, cnt);
1686         if (IS_ERR(buf))
1687                 return PTR_ERR(buf);
1688
1689         mutex_lock(&event_mutex);
1690         file = event_file_data(filp);
1691         if (file)
1692                 err = apply_event_filter(file, buf);
1693         mutex_unlock(&event_mutex);
1694
1695         kfree(buf);
1696         if (err < 0)
1697                 return err;
1698
1699         *ppos += cnt;
1700
1701         return cnt;
1702 }
1703
1704 static LIST_HEAD(event_subsystems);
1705
1706 static int subsystem_open(struct inode *inode, struct file *filp)
1707 {
1708         struct event_subsystem *system = NULL;
1709         struct trace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1710         struct trace_array *tr;
1711         int ret;
1712
1713         if (tracing_is_disabled())
1714                 return -ENODEV;
1715
1716         /* Make sure the system still exists */
1717         mutex_lock(&event_mutex);
1718         mutex_lock(&trace_types_lock);
1719         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1720                 list_for_each_entry(dir, &tr->systems, list) {
1721                         if (dir == inode->i_private) {
1722                                 /* Don't open systems with no events */
1723                                 if (dir->nr_events) {
1724                                         __get_system_dir(dir);
1725                                         system = dir->subsystem;
1726                                 }
1727                                 goto exit_loop;
1728                         }
1729                 }
1730         }
1731  exit_loop:
1732         mutex_unlock(&trace_types_lock);
1733         mutex_unlock(&event_mutex);
1734
1735         if (!system)
1736                 return -ENODEV;
1737
1738         /* Some versions of gcc think dir can be uninitialized here */
1739         WARN_ON(!dir);
1740
1741         /* Still need to increment the ref count of the system */
1742         if (trace_array_get(tr) < 0) {
1743                 put_system(dir);
1744                 return -ENODEV;
1745         }
1746
1747         ret = tracing_open_generic(inode, filp);
1748         if (ret < 0) {
1749                 trace_array_put(tr);
1750                 put_system(dir);
1751         }
1752
1753         return ret;
1754 }
1755
1756 static int system_tr_open(struct inode *inode, struct file *filp)
1757 {
1758         struct trace_subsystem_dir *dir;
1759         struct trace_array *tr = inode->i_private;
1760         int ret;
1761
1762         /* Make a temporary dir that has no system but points to tr */
1763         dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1764         if (!dir)
1765                 return -ENOMEM;
1766
1767         ret = tracing_open_generic_tr(inode, filp);
1768         if (ret < 0) {
1769                 kfree(dir);
1770                 return ret;
1771         }
1772         dir->tr = tr;
1773         filp->private_data = dir;
1774
1775         return 0;
1776 }
1777
1778 static int subsystem_release(struct inode *inode, struct file *file)
1779 {
1780         struct trace_subsystem_dir *dir = file->private_data;
1781
1782         trace_array_put(dir->tr);
1783
1784         /*
1785          * If dir->subsystem is NULL, then this is a temporary
1786          * descriptor that was made for a trace_array to enable
1787          * all subsystems.
1788          */
1789         if (dir->subsystem)
1790                 put_system(dir);
1791         else
1792                 kfree(dir);
1793
1794         return 0;
1795 }
1796
1797 static ssize_t
1798 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1799                       loff_t *ppos)
1800 {
1801         struct trace_subsystem_dir *dir = filp->private_data;
1802         struct event_subsystem *system = dir->subsystem;
1803         struct trace_seq *s;
1804         int r;
1805
1806         if (*ppos)
1807                 return 0;
1808
1809         s = kmalloc(sizeof(*s), GFP_KERNEL);
1810         if (!s)
1811                 return -ENOMEM;
1812
1813         trace_seq_init(s);
1814
1815         print_subsystem_event_filter(system, s);
1816         r = simple_read_from_buffer(ubuf, cnt, ppos,
1817                                     s->buffer, trace_seq_used(s));
1818
1819         kfree(s);
1820
1821         return r;
1822 }
1823
1824 static ssize_t
1825 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1826                        loff_t *ppos)
1827 {
1828         struct trace_subsystem_dir *dir = filp->private_data;
1829         char *buf;
1830         int err;
1831
1832         if (cnt >= PAGE_SIZE)
1833                 return -EINVAL;
1834
1835         buf = memdup_user_nul(ubuf, cnt);
1836         if (IS_ERR(buf))
1837                 return PTR_ERR(buf);
1838
1839         err = apply_subsystem_event_filter(dir, buf);
1840         kfree(buf);
1841         if (err < 0)
1842                 return err;
1843
1844         *ppos += cnt;
1845
1846         return cnt;
1847 }
1848
1849 static ssize_t
1850 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1851 {
1852         int (*func)(struct trace_seq *s) = filp->private_data;
1853         struct trace_seq *s;
1854         int r;
1855
1856         if (*ppos)
1857                 return 0;
1858
1859         s = kmalloc(sizeof(*s), GFP_KERNEL);
1860         if (!s)
1861                 return -ENOMEM;
1862
1863         trace_seq_init(s);
1864
1865         func(s);
1866         r = simple_read_from_buffer(ubuf, cnt, ppos,
1867                                     s->buffer, trace_seq_used(s));
1868
1869         kfree(s);
1870
1871         return r;
1872 }
1873
1874 static void ignore_task_cpu(void *data)
1875 {
1876         struct trace_array *tr = data;
1877         struct trace_pid_list *pid_list;
1878         struct trace_pid_list *no_pid_list;
1879
1880         /*
1881          * This function is called by on_each_cpu() while the
1882          * event_mutex is held.
1883          */
1884         pid_list = rcu_dereference_protected(tr->filtered_pids,
1885                                              mutex_is_locked(&event_mutex));
1886         no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
1887                                              mutex_is_locked(&event_mutex));
1888
1889         this_cpu_write(tr->array_buffer.data->ignore_pid,
1890                        trace_ignore_this_task(pid_list, no_pid_list, current));
1891 }
1892
1893 static void register_pid_events(struct trace_array *tr)
1894 {
1895         /*
1896          * Register a probe that is called before all other probes
1897          * to set ignore_pid if next or prev do not match.
1898          * Register a probe this is called after all other probes
1899          * to only keep ignore_pid set if next pid matches.
1900          */
1901         register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1902                                          tr, INT_MAX);
1903         register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1904                                          tr, 0);
1905
1906         register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1907                                          tr, INT_MAX);
1908         register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1909                                          tr, 0);
1910
1911         register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1912                                              tr, INT_MAX);
1913         register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1914                                              tr, 0);
1915
1916         register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1917                                          tr, INT_MAX);
1918         register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1919                                          tr, 0);
1920 }
1921
1922 static ssize_t
1923 event_pid_write(struct file *filp, const char __user *ubuf,
1924                 size_t cnt, loff_t *ppos, int type)
1925 {
1926         struct seq_file *m = filp->private_data;
1927         struct trace_array *tr = m->private;
1928         struct trace_pid_list *filtered_pids = NULL;
1929         struct trace_pid_list *other_pids = NULL;
1930         struct trace_pid_list *pid_list;
1931         struct trace_event_file *file;
1932         ssize_t ret;
1933
1934         if (!cnt)
1935                 return 0;
1936
1937         ret = tracing_update_buffers();
1938         if (ret < 0)
1939                 return ret;
1940
1941         mutex_lock(&event_mutex);
1942
1943         if (type == TRACE_PIDS) {
1944                 filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1945                                                           lockdep_is_held(&event_mutex));
1946                 other_pids = rcu_dereference_protected(tr->filtered_no_pids,
1947                                                           lockdep_is_held(&event_mutex));
1948         } else {
1949                 filtered_pids = rcu_dereference_protected(tr->filtered_no_pids,
1950                                                           lockdep_is_held(&event_mutex));
1951                 other_pids = rcu_dereference_protected(tr->filtered_pids,
1952                                                           lockdep_is_held(&event_mutex));
1953         }
1954
1955         ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
1956         if (ret < 0)
1957                 goto out;
1958
1959         if (type == TRACE_PIDS)
1960                 rcu_assign_pointer(tr->filtered_pids, pid_list);
1961         else
1962                 rcu_assign_pointer(tr->filtered_no_pids, pid_list);
1963
1964         list_for_each_entry(file, &tr->events, list) {
1965                 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
1966         }
1967
1968         if (filtered_pids) {
1969                 tracepoint_synchronize_unregister();
1970                 trace_free_pid_list(filtered_pids);
1971         } else if (pid_list && !other_pids) {
1972                 register_pid_events(tr);
1973         }
1974
1975         /*
1976          * Ignoring of pids is done at task switch. But we have to
1977          * check for those tasks that are currently running.
1978          * Always do this in case a pid was appended or removed.
1979          */
1980         on_each_cpu(ignore_task_cpu, tr, 1);
1981
1982  out:
1983         mutex_unlock(&event_mutex);
1984
1985         if (ret > 0)
1986                 *ppos += ret;
1987
1988         return ret;
1989 }
1990
1991 static ssize_t
1992 ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
1993                        size_t cnt, loff_t *ppos)
1994 {
1995         return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
1996 }
1997
1998 static ssize_t
1999 ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
2000                         size_t cnt, loff_t *ppos)
2001 {
2002         return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
2003 }
2004
2005 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
2006 static int ftrace_event_set_open(struct inode *inode, struct file *file);
2007 static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
2008 static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
2009 static int ftrace_event_release(struct inode *inode, struct file *file);
2010
2011 static const struct seq_operations show_event_seq_ops = {
2012         .start = t_start,
2013         .next = t_next,
2014         .show = t_show,
2015         .stop = t_stop,
2016 };
2017
2018 static const struct seq_operations show_set_event_seq_ops = {
2019         .start = s_start,
2020         .next = s_next,
2021         .show = t_show,
2022         .stop = t_stop,
2023 };
2024
2025 static const struct seq_operations show_set_pid_seq_ops = {
2026         .start = p_start,
2027         .next = p_next,
2028         .show = trace_pid_show,
2029         .stop = p_stop,
2030 };
2031
2032 static const struct seq_operations show_set_no_pid_seq_ops = {
2033         .start = np_start,
2034         .next = np_next,
2035         .show = trace_pid_show,
2036         .stop = p_stop,
2037 };
2038
2039 static const struct file_operations ftrace_avail_fops = {
2040         .open = ftrace_event_avail_open,
2041         .read = seq_read,
2042         .llseek = seq_lseek,
2043         .release = seq_release,
2044 };
2045
2046 static const struct file_operations ftrace_set_event_fops = {
2047         .open = ftrace_event_set_open,
2048         .read = seq_read,
2049         .write = ftrace_event_write,
2050         .llseek = seq_lseek,
2051         .release = ftrace_event_release,
2052 };
2053
2054 static const struct file_operations ftrace_set_event_pid_fops = {
2055         .open = ftrace_event_set_pid_open,
2056         .read = seq_read,
2057         .write = ftrace_event_pid_write,
2058         .llseek = seq_lseek,
2059         .release = ftrace_event_release,
2060 };
2061
2062 static const struct file_operations ftrace_set_event_notrace_pid_fops = {
2063         .open = ftrace_event_set_npid_open,
2064         .read = seq_read,
2065         .write = ftrace_event_npid_write,
2066         .llseek = seq_lseek,
2067         .release = ftrace_event_release,
2068 };
2069
2070 static const struct file_operations ftrace_enable_fops = {
2071         .open = tracing_open_generic,
2072         .read = event_enable_read,
2073         .write = event_enable_write,
2074         .llseek = default_llseek,
2075 };
2076
2077 static const struct file_operations ftrace_event_format_fops = {
2078         .open = trace_format_open,
2079         .read = seq_read,
2080         .llseek = seq_lseek,
2081         .release = seq_release,
2082 };
2083
2084 static const struct file_operations ftrace_event_id_fops = {
2085         .read = event_id_read,
2086         .llseek = default_llseek,
2087 };
2088
2089 static const struct file_operations ftrace_event_filter_fops = {
2090         .open = tracing_open_generic,
2091         .read = event_filter_read,
2092         .write = event_filter_write,
2093         .llseek = default_llseek,
2094 };
2095
2096 static const struct file_operations ftrace_subsystem_filter_fops = {
2097         .open = subsystem_open,
2098         .read = subsystem_filter_read,
2099         .write = subsystem_filter_write,
2100         .llseek = default_llseek,
2101         .release = subsystem_release,
2102 };
2103
2104 static const struct file_operations ftrace_system_enable_fops = {
2105         .open = subsystem_open,
2106         .read = system_enable_read,
2107         .write = system_enable_write,
2108         .llseek = default_llseek,
2109         .release = subsystem_release,
2110 };
2111
2112 static const struct file_operations ftrace_tr_enable_fops = {
2113         .open = system_tr_open,
2114         .read = system_enable_read,
2115         .write = system_enable_write,
2116         .llseek = default_llseek,
2117         .release = subsystem_release,
2118 };
2119
2120 static const struct file_operations ftrace_show_header_fops = {
2121         .open = tracing_open_generic,
2122         .read = show_header,
2123         .llseek = default_llseek,
2124 };
2125
2126 static int
2127 ftrace_event_open(struct inode *inode, struct file *file,
2128                   const struct seq_operations *seq_ops)
2129 {
2130         struct seq_file *m;
2131         int ret;
2132
2133         ret = security_locked_down(LOCKDOWN_TRACEFS);
2134         if (ret)
2135                 return ret;
2136
2137         ret = seq_open(file, seq_ops);
2138         if (ret < 0)
2139                 return ret;
2140         m = file->private_data;
2141         /* copy tr over to seq ops */
2142         m->private = inode->i_private;
2143
2144         return ret;
2145 }
2146
2147 static int ftrace_event_release(struct inode *inode, struct file *file)
2148 {
2149         struct trace_array *tr = inode->i_private;
2150
2151         trace_array_put(tr);
2152
2153         return seq_release(inode, file);
2154 }
2155
2156 static int
2157 ftrace_event_avail_open(struct inode *inode, struct file *file)
2158 {
2159         const struct seq_operations *seq_ops = &show_event_seq_ops;
2160
2161         /* Checks for tracefs lockdown */
2162         return ftrace_event_open(inode, file, seq_ops);
2163 }
2164
2165 static int
2166 ftrace_event_set_open(struct inode *inode, struct file *file)
2167 {
2168         const struct seq_operations *seq_ops = &show_set_event_seq_ops;
2169         struct trace_array *tr = inode->i_private;
2170         int ret;
2171
2172         ret = tracing_check_open_get_tr(tr);
2173         if (ret)
2174                 return ret;
2175
2176         if ((file->f_mode & FMODE_WRITE) &&
2177             (file->f_flags & O_TRUNC))
2178                 ftrace_clear_events(tr);
2179
2180         ret = ftrace_event_open(inode, file, seq_ops);
2181         if (ret < 0)
2182                 trace_array_put(tr);
2183         return ret;
2184 }
2185
2186 static int
2187 ftrace_event_set_pid_open(struct inode *inode, struct file *file)
2188 {
2189         const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
2190         struct trace_array *tr = inode->i_private;
2191         int ret;
2192
2193         ret = tracing_check_open_get_tr(tr);
2194         if (ret)
2195                 return ret;
2196
2197         if ((file->f_mode & FMODE_WRITE) &&
2198             (file->f_flags & O_TRUNC))
2199                 ftrace_clear_event_pids(tr, TRACE_PIDS);
2200
2201         ret = ftrace_event_open(inode, file, seq_ops);
2202         if (ret < 0)
2203                 trace_array_put(tr);
2204         return ret;
2205 }
2206
2207 static int
2208 ftrace_event_set_npid_open(struct inode *inode, struct file *file)
2209 {
2210         const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops;
2211         struct trace_array *tr = inode->i_private;
2212         int ret;
2213
2214         ret = tracing_check_open_get_tr(tr);
2215         if (ret)
2216                 return ret;
2217
2218         if ((file->f_mode & FMODE_WRITE) &&
2219             (file->f_flags & O_TRUNC))
2220                 ftrace_clear_event_pids(tr, TRACE_NO_PIDS);
2221
2222         ret = ftrace_event_open(inode, file, seq_ops);
2223         if (ret < 0)
2224                 trace_array_put(tr);
2225         return ret;
2226 }
2227
2228 static struct event_subsystem *
2229 create_new_subsystem(const char *name)
2230 {
2231         struct event_subsystem *system;
2232
2233         /* need to create new entry */
2234         system = kmalloc(sizeof(*system), GFP_KERNEL);
2235         if (!system)
2236                 return NULL;
2237
2238         system->ref_count = 1;
2239
2240         /* Only allocate if dynamic (kprobes and modules) */
2241         system->name = kstrdup_const(name, GFP_KERNEL);
2242         if (!system->name)
2243                 goto out_free;
2244
2245         system->filter = NULL;
2246
2247         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
2248         if (!system->filter)
2249                 goto out_free;
2250
2251         list_add(&system->list, &event_subsystems);
2252
2253         return system;
2254
2255  out_free:
2256         kfree_const(system->name);
2257         kfree(system);
2258         return NULL;
2259 }
2260
2261 static struct dentry *
2262 event_subsystem_dir(struct trace_array *tr, const char *name,
2263                     struct trace_event_file *file, struct dentry *parent)
2264 {
2265         struct trace_subsystem_dir *dir;
2266         struct event_subsystem *system;
2267         struct dentry *entry;
2268
2269         /* First see if we did not already create this dir */
2270         list_for_each_entry(dir, &tr->systems, list) {
2271                 system = dir->subsystem;
2272                 if (strcmp(system->name, name) == 0) {
2273                         dir->nr_events++;
2274                         file->system = dir;
2275                         return dir->entry;
2276                 }
2277         }
2278
2279         /* Now see if the system itself exists. */
2280         list_for_each_entry(system, &event_subsystems, list) {
2281                 if (strcmp(system->name, name) == 0)
2282                         break;
2283         }
2284         /* Reset system variable when not found */
2285         if (&system->list == &event_subsystems)
2286                 system = NULL;
2287
2288         dir = kmalloc(sizeof(*dir), GFP_KERNEL);
2289         if (!dir)
2290                 goto out_fail;
2291
2292         if (!system) {
2293                 system = create_new_subsystem(name);
2294                 if (!system)
2295                         goto out_free;
2296         } else
2297                 __get_system(system);
2298
2299         dir->entry = tracefs_create_dir(name, parent);
2300         if (!dir->entry) {
2301                 pr_warn("Failed to create system directory %s\n", name);
2302                 __put_system(system);
2303                 goto out_free;
2304         }
2305
2306         dir->tr = tr;
2307         dir->ref_count = 1;
2308         dir->nr_events = 1;
2309         dir->subsystem = system;
2310         file->system = dir;
2311
2312         /* the ftrace system is special, do not create enable or filter files */
2313         if (strcmp(name, "ftrace") != 0) {
2314
2315                 entry = tracefs_create_file("filter", 0644, dir->entry, dir,
2316                                             &ftrace_subsystem_filter_fops);
2317                 if (!entry) {
2318                         kfree(system->filter);
2319                         system->filter = NULL;
2320                         pr_warn("Could not create tracefs '%s/filter' entry\n", name);
2321                 }
2322
2323                 trace_create_file("enable", 0644, dir->entry, dir,
2324                                   &ftrace_system_enable_fops);
2325         }
2326
2327         list_add(&dir->list, &tr->systems);
2328
2329         return dir->entry;
2330
2331  out_free:
2332         kfree(dir);
2333  out_fail:
2334         /* Only print this message if failed on memory allocation */
2335         if (!dir || !system)
2336                 pr_warn("No memory to create event subsystem %s\n", name);
2337         return NULL;
2338 }
2339
2340 static int
2341 event_define_fields(struct trace_event_call *call)
2342 {
2343         struct list_head *head;
2344         int ret = 0;
2345
2346         /*
2347          * Other events may have the same class. Only update
2348          * the fields if they are not already defined.
2349          */
2350         head = trace_get_fields(call);
2351         if (list_empty(head)) {
2352                 struct trace_event_fields *field = call->class->fields_array;
2353                 unsigned int offset = sizeof(struct trace_entry);
2354
2355                 for (; field->type; field++) {
2356                         if (field->type == TRACE_FUNCTION_TYPE) {
2357                                 field->define_fields(call);
2358                                 break;
2359                         }
2360
2361                         offset = ALIGN(offset, field->align);
2362                         ret = trace_define_field(call, field->type, field->name,
2363                                                  offset, field->size,
2364                                                  field->is_signed, field->filter_type);
2365                         if (WARN_ON_ONCE(ret)) {
2366                                 pr_err("error code is %d\n", ret);
2367                                 break;
2368                         }
2369
2370                         offset += field->size;
2371                 }
2372         }
2373
2374         return ret;
2375 }
2376
2377 static int
2378 event_create_dir(struct dentry *parent, struct trace_event_file *file)
2379 {
2380         struct trace_event_call *call = file->event_call;
2381         struct trace_array *tr = file->tr;
2382         struct dentry *d_events;
2383         const char *name;
2384         int ret;
2385
2386         /*
2387          * If the trace point header did not define TRACE_SYSTEM
2388          * then the system would be called "TRACE_SYSTEM".
2389          */
2390         if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
2391                 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
2392                 if (!d_events)
2393                         return -ENOMEM;
2394         } else
2395                 d_events = parent;
2396
2397         name = trace_event_name(call);
2398         file->dir = tracefs_create_dir(name, d_events);
2399         if (!file->dir) {
2400                 pr_warn("Could not create tracefs '%s' directory\n", name);
2401                 return -1;
2402         }
2403
2404         if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
2405                 trace_create_file("enable", 0644, file->dir, file,
2406                                   &ftrace_enable_fops);
2407
2408 #ifdef CONFIG_PERF_EVENTS
2409         if (call->event.type && call->class->reg)
2410                 trace_create_file("id", 0444, file->dir,
2411                                   (void *)(long)call->event.type,
2412                                   &ftrace_event_id_fops);
2413 #endif
2414
2415         ret = event_define_fields(call);
2416         if (ret < 0) {
2417                 pr_warn("Could not initialize trace point events/%s\n", name);
2418                 return ret;
2419         }
2420
2421         /*
2422          * Only event directories that can be enabled should have
2423          * triggers or filters.
2424          */
2425         if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
2426                 trace_create_file("filter", 0644, file->dir, file,
2427                                   &ftrace_event_filter_fops);
2428
2429                 trace_create_file("trigger", 0644, file->dir, file,
2430                                   &event_trigger_fops);
2431         }
2432
2433 #ifdef CONFIG_HIST_TRIGGERS
2434         trace_create_file("hist", 0444, file->dir, file,
2435                           &event_hist_fops);
2436 #endif
2437 #ifdef CONFIG_HIST_TRIGGERS_DEBUG
2438         trace_create_file("hist_debug", 0444, file->dir, file,
2439                           &event_hist_debug_fops);
2440 #endif
2441         trace_create_file("format", 0444, file->dir, call,
2442                           &ftrace_event_format_fops);
2443
2444 #ifdef CONFIG_TRACE_EVENT_INJECT
2445         if (call->event.type && call->class->reg)
2446                 trace_create_file("inject", 0200, file->dir, file,
2447                                   &event_inject_fops);
2448 #endif
2449
2450         return 0;
2451 }
2452
2453 static void remove_event_from_tracers(struct trace_event_call *call)
2454 {
2455         struct trace_event_file *file;
2456         struct trace_array *tr;
2457
2458         do_for_each_event_file_safe(tr, file) {
2459                 if (file->event_call != call)
2460                         continue;
2461
2462                 remove_event_file_dir(file);
2463                 /*
2464                  * The do_for_each_event_file_safe() is
2465                  * a double loop. After finding the call for this
2466                  * trace_array, we use break to jump to the next
2467                  * trace_array.
2468                  */
2469                 break;
2470         } while_for_each_event_file();
2471 }
2472
2473 static void event_remove(struct trace_event_call *call)
2474 {
2475         struct trace_array *tr;
2476         struct trace_event_file *file;
2477
2478         do_for_each_event_file(tr, file) {
2479                 if (file->event_call != call)
2480                         continue;
2481
2482                 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2483                         tr->clear_trace = true;
2484
2485                 ftrace_event_enable_disable(file, 0);
2486                 /*
2487                  * The do_for_each_event_file() is
2488                  * a double loop. After finding the call for this
2489                  * trace_array, we use break to jump to the next
2490                  * trace_array.
2491                  */
2492                 break;
2493         } while_for_each_event_file();
2494
2495         if (call->event.funcs)
2496                 __unregister_trace_event(&call->event);
2497         remove_event_from_tracers(call);
2498         list_del(&call->list);
2499 }
2500
2501 static int event_init(struct trace_event_call *call)
2502 {
2503         int ret = 0;
2504         const char *name;
2505
2506         name = trace_event_name(call);
2507         if (WARN_ON(!name))
2508                 return -EINVAL;
2509
2510         if (call->class->raw_init) {
2511                 ret = call->class->raw_init(call);
2512                 if (ret < 0 && ret != -ENOSYS)
2513                         pr_warn("Could not initialize trace events/%s\n", name);
2514         }
2515
2516         return ret;
2517 }
2518
2519 static int
2520 __register_event(struct trace_event_call *call, struct module *mod)
2521 {
2522         int ret;
2523
2524         ret = event_init(call);
2525         if (ret < 0)
2526                 return ret;
2527
2528         list_add(&call->list, &ftrace_events);
2529         if (call->flags & TRACE_EVENT_FL_DYNAMIC)
2530                 atomic_set(&call->refcnt, 0);
2531         else
2532                 call->module = mod;
2533
2534         return 0;
2535 }
2536
2537 static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2538 {
2539         int rlen;
2540         int elen;
2541
2542         /* Find the length of the eval value as a string */
2543         elen = snprintf(ptr, 0, "%ld", map->eval_value);
2544         /* Make sure there's enough room to replace the string with the value */
2545         if (len < elen)
2546                 return NULL;
2547
2548         snprintf(ptr, elen + 1, "%ld", map->eval_value);
2549
2550         /* Get the rest of the string of ptr */
2551         rlen = strlen(ptr + len);
2552         memmove(ptr + elen, ptr + len, rlen);
2553         /* Make sure we end the new string */
2554         ptr[elen + rlen] = 0;
2555
2556         return ptr + elen;
2557 }
2558
2559 static void update_event_printk(struct trace_event_call *call,
2560                                 struct trace_eval_map *map)
2561 {
2562         char *ptr;
2563         int quote = 0;
2564         int len = strlen(map->eval_string);
2565
2566         for (ptr = call->print_fmt; *ptr; ptr++) {
2567                 if (*ptr == '\\') {
2568                         ptr++;
2569                         /* paranoid */
2570                         if (!*ptr)
2571                                 break;
2572                         continue;
2573                 }
2574                 if (*ptr == '"') {
2575                         quote ^= 1;
2576                         continue;
2577                 }
2578                 if (quote)
2579                         continue;
2580                 if (isdigit(*ptr)) {
2581                         /* skip numbers */
2582                         do {
2583                                 ptr++;
2584                                 /* Check for alpha chars like ULL */
2585                         } while (isalnum(*ptr));
2586                         if (!*ptr)
2587                                 break;
2588                         /*
2589                          * A number must have some kind of delimiter after
2590                          * it, and we can ignore that too.
2591                          */
2592                         continue;
2593                 }
2594                 if (isalpha(*ptr) || *ptr == '_') {
2595                         if (strncmp(map->eval_string, ptr, len) == 0 &&
2596                             !isalnum(ptr[len]) && ptr[len] != '_') {
2597                                 ptr = eval_replace(ptr, map, len);
2598                                 /* enum/sizeof string smaller than value */
2599                                 if (WARN_ON_ONCE(!ptr))
2600                                         return;
2601                                 /*
2602                                  * No need to decrement here, as eval_replace()
2603                                  * returns the pointer to the character passed
2604                                  * the eval, and two evals can not be placed
2605                                  * back to back without something in between.
2606                                  * We can skip that something in between.
2607                                  */
2608                                 continue;
2609                         }
2610                 skip_more:
2611                         do {
2612                                 ptr++;
2613                         } while (isalnum(*ptr) || *ptr == '_');
2614                         if (!*ptr)
2615                                 break;
2616                         /*
2617                          * If what comes after this variable is a '.' or
2618                          * '->' then we can continue to ignore that string.
2619                          */
2620                         if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2621                                 ptr += *ptr == '.' ? 1 : 2;
2622                                 if (!*ptr)
2623                                         break;
2624                                 goto skip_more;
2625                         }
2626                         /*
2627                          * Once again, we can skip the delimiter that came
2628                          * after the string.
2629                          */
2630                         continue;
2631                 }
2632         }
2633 }
2634
2635 void trace_event_eval_update(struct trace_eval_map **map, int len)
2636 {
2637         struct trace_event_call *call, *p;
2638         const char *last_system = NULL;
2639         bool first = false;
2640         int last_i;
2641         int i;
2642
2643         down_write(&trace_event_sem);
2644         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2645                 /* events are usually grouped together with systems */
2646                 if (!last_system || call->class->system != last_system) {
2647                         first = true;
2648                         last_i = 0;
2649                         last_system = call->class->system;
2650                 }
2651
2652                 /*
2653                  * Since calls are grouped by systems, the likelihood that the
2654                  * next call in the iteration belongs to the same system as the
2655                  * previous call is high. As an optimization, we skip searching
2656                  * for a map[] that matches the call's system if the last call
2657                  * was from the same system. That's what last_i is for. If the
2658                  * call has the same system as the previous call, then last_i
2659                  * will be the index of the first map[] that has a matching
2660                  * system.
2661                  */
2662                 for (i = last_i; i < len; i++) {
2663                         if (call->class->system == map[i]->system) {
2664                                 /* Save the first system if need be */
2665                                 if (first) {
2666                                         last_i = i;
2667                                         first = false;
2668                                 }
2669                                 update_event_printk(call, map[i]);
2670                         }
2671                 }
2672         }
2673         up_write(&trace_event_sem);
2674 }
2675
2676 static struct trace_event_file *
2677 trace_create_new_event(struct trace_event_call *call,
2678                        struct trace_array *tr)
2679 {
2680         struct trace_event_file *file;
2681
2682         file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2683         if (!file)
2684                 return NULL;
2685
2686         file->event_call = call;
2687         file->tr = tr;
2688         atomic_set(&file->sm_ref, 0);
2689         atomic_set(&file->tm_ref, 0);
2690         INIT_LIST_HEAD(&file->triggers);
2691         list_add(&file->list, &tr->events);
2692
2693         return file;
2694 }
2695
2696 /* Add an event to a trace directory */
2697 static int
2698 __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2699 {
2700         struct trace_event_file *file;
2701
2702         file = trace_create_new_event(call, tr);
2703         if (!file)
2704                 return -ENOMEM;
2705
2706         if (eventdir_initialized)
2707                 return event_create_dir(tr->event_dir, file);
2708         else
2709                 return event_define_fields(call);
2710 }
2711
2712 /*
2713  * Just create a descriptor for early init. A descriptor is required
2714  * for enabling events at boot. We want to enable events before
2715  * the filesystem is initialized.
2716  */
2717 static int
2718 __trace_early_add_new_event(struct trace_event_call *call,
2719                             struct trace_array *tr)
2720 {
2721         struct trace_event_file *file;
2722
2723         file = trace_create_new_event(call, tr);
2724         if (!file)
2725                 return -ENOMEM;
2726
2727         return event_define_fields(call);
2728 }
2729
2730 struct ftrace_module_file_ops;
2731 static void __add_event_to_tracers(struct trace_event_call *call);
2732
2733 /* Add an additional event_call dynamically */
2734 int trace_add_event_call(struct trace_event_call *call)
2735 {
2736         int ret;
2737         lockdep_assert_held(&event_mutex);
2738
2739         mutex_lock(&trace_types_lock);
2740
2741         ret = __register_event(call, NULL);
2742         if (ret >= 0)
2743                 __add_event_to_tracers(call);
2744
2745         mutex_unlock(&trace_types_lock);
2746         return ret;
2747 }
2748
2749 /*
2750  * Must be called under locking of trace_types_lock, event_mutex and
2751  * trace_event_sem.
2752  */
2753 static void __trace_remove_event_call(struct trace_event_call *call)
2754 {
2755         event_remove(call);
2756         trace_destroy_fields(call);
2757         free_event_filter(call->filter);
2758         call->filter = NULL;
2759 }
2760
2761 static int probe_remove_event_call(struct trace_event_call *call)
2762 {
2763         struct trace_array *tr;
2764         struct trace_event_file *file;
2765
2766 #ifdef CONFIG_PERF_EVENTS
2767         if (call->perf_refcount)
2768                 return -EBUSY;
2769 #endif
2770         do_for_each_event_file(tr, file) {
2771                 if (file->event_call != call)
2772                         continue;
2773                 /*
2774                  * We can't rely on ftrace_event_enable_disable(enable => 0)
2775                  * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
2776                  * TRACE_REG_UNREGISTER.
2777                  */
2778                 if (file->flags & EVENT_FILE_FL_ENABLED)
2779                         return -EBUSY;
2780                 /*
2781                  * The do_for_each_event_file_safe() is
2782                  * a double loop. After finding the call for this
2783                  * trace_array, we use break to jump to the next
2784                  * trace_array.
2785                  */
2786                 break;
2787         } while_for_each_event_file();
2788
2789         __trace_remove_event_call(call);
2790
2791         return 0;
2792 }
2793
2794 /* Remove an event_call */
2795 int trace_remove_event_call(struct trace_event_call *call)
2796 {
2797         int ret;
2798
2799         lockdep_assert_held(&event_mutex);
2800
2801         mutex_lock(&trace_types_lock);
2802         down_write(&trace_event_sem);
2803         ret = probe_remove_event_call(call);
2804         up_write(&trace_event_sem);
2805         mutex_unlock(&trace_types_lock);
2806
2807         return ret;
2808 }
2809
2810 #define for_each_event(event, start, end)                       \
2811         for (event = start;                                     \
2812              (unsigned long)event < (unsigned long)end;         \
2813              event++)
2814
2815 #ifdef CONFIG_MODULES
2816
2817 static void trace_module_add_events(struct module *mod)
2818 {
2819         struct trace_event_call **call, **start, **end;
2820
2821         if (!mod->num_trace_events)
2822                 return;
2823
2824         /* Don't add infrastructure for mods without tracepoints */
2825         if (trace_module_has_bad_taint(mod)) {
2826                 pr_err("%s: module has bad taint, not creating trace events\n",
2827                        mod->name);
2828                 return;
2829         }
2830
2831         start = mod->trace_events;
2832         end = mod->trace_events + mod->num_trace_events;
2833
2834         for_each_event(call, start, end) {
2835                 __register_event(*call, mod);
2836                 __add_event_to_tracers(*call);
2837         }
2838 }
2839
2840 static void trace_module_remove_events(struct module *mod)
2841 {
2842         struct trace_event_call *call, *p;
2843
2844         down_write(&trace_event_sem);
2845         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2846                 if ((call->flags & TRACE_EVENT_FL_DYNAMIC) || !call->module)
2847                         continue;
2848                 if (call->module == mod)
2849                         __trace_remove_event_call(call);
2850         }
2851         up_write(&trace_event_sem);
2852
2853         /*
2854          * It is safest to reset the ring buffer if the module being unloaded
2855          * registered any events that were used. The only worry is if
2856          * a new module gets loaded, and takes on the same id as the events
2857          * of this module. When printing out the buffer, traced events left
2858          * over from this module may be passed to the new module events and
2859          * unexpected results may occur.
2860          */
2861         tracing_reset_all_online_cpus();
2862 }
2863
2864 static int trace_module_notify(struct notifier_block *self,
2865                                unsigned long val, void *data)
2866 {
2867         struct module *mod = data;
2868
2869         mutex_lock(&event_mutex);
2870         mutex_lock(&trace_types_lock);
2871         switch (val) {
2872         case MODULE_STATE_COMING:
2873                 trace_module_add_events(mod);
2874                 break;
2875         case MODULE_STATE_GOING:
2876                 trace_module_remove_events(mod);
2877                 break;
2878         }
2879         mutex_unlock(&trace_types_lock);
2880         mutex_unlock(&event_mutex);
2881
2882         return NOTIFY_OK;
2883 }
2884
2885 static struct notifier_block trace_module_nb = {
2886         .notifier_call = trace_module_notify,
2887         .priority = 1, /* higher than trace.c module notify */
2888 };
2889 #endif /* CONFIG_MODULES */
2890
2891 /* Create a new event directory structure for a trace directory. */
2892 static void
2893 __trace_add_event_dirs(struct trace_array *tr)
2894 {
2895         struct trace_event_call *call;
2896         int ret;
2897
2898         list_for_each_entry(call, &ftrace_events, list) {
2899                 ret = __trace_add_new_event(call, tr);
2900                 if (ret < 0)
2901                         pr_warn("Could not create directory for event %s\n",
2902                                 trace_event_name(call));
2903         }
2904 }
2905
2906 /* Returns any file that matches the system and event */
2907 struct trace_event_file *
2908 __find_event_file(struct trace_array *tr, const char *system, const char *event)
2909 {
2910         struct trace_event_file *file;
2911         struct trace_event_call *call;
2912         const char *name;
2913
2914         list_for_each_entry(file, &tr->events, list) {
2915
2916                 call = file->event_call;
2917                 name = trace_event_name(call);
2918
2919                 if (!name || !call->class)
2920                         continue;
2921
2922                 if (strcmp(event, name) == 0 &&
2923                     strcmp(system, call->class->system) == 0)
2924                         return file;
2925         }
2926         return NULL;
2927 }
2928
2929 /* Returns valid trace event files that match system and event */
2930 struct trace_event_file *
2931 find_event_file(struct trace_array *tr, const char *system, const char *event)
2932 {
2933         struct trace_event_file *file;
2934
2935         file = __find_event_file(tr, system, event);
2936         if (!file || !file->event_call->class->reg ||
2937             file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
2938                 return NULL;
2939
2940         return file;
2941 }
2942
2943 /**
2944  * trace_get_event_file - Find and return a trace event file
2945  * @instance: The name of the trace instance containing the event
2946  * @system: The name of the system containing the event
2947  * @event: The name of the event
2948  *
2949  * Return a trace event file given the trace instance name, trace
2950  * system, and trace event name.  If the instance name is NULL, it
2951  * refers to the top-level trace array.
2952  *
2953  * This function will look it up and return it if found, after calling
2954  * trace_array_get() to prevent the instance from going away, and
2955  * increment the event's module refcount to prevent it from being
2956  * removed.
2957  *
2958  * To release the file, call trace_put_event_file(), which will call
2959  * trace_array_put() and decrement the event's module refcount.
2960  *
2961  * Return: The trace event on success, ERR_PTR otherwise.
2962  */
2963 struct trace_event_file *trace_get_event_file(const char *instance,
2964                                               const char *system,
2965                                               const char *event)
2966 {
2967         struct trace_array *tr = top_trace_array();
2968         struct trace_event_file *file = NULL;
2969         int ret = -EINVAL;
2970
2971         if (instance) {
2972                 tr = trace_array_find_get(instance);
2973                 if (!tr)
2974                         return ERR_PTR(-ENOENT);
2975         } else {
2976                 ret = trace_array_get(tr);
2977                 if (ret)
2978                         return ERR_PTR(ret);
2979         }
2980
2981         mutex_lock(&event_mutex);
2982
2983         file = find_event_file(tr, system, event);
2984         if (!file) {
2985                 trace_array_put(tr);
2986                 ret = -EINVAL;
2987                 goto out;
2988         }
2989
2990         /* Don't let event modules unload while in use */
2991         ret = trace_event_try_get_ref(file->event_call);
2992         if (!ret) {
2993                 trace_array_put(tr);
2994                 ret = -EBUSY;
2995                 goto out;
2996         }
2997
2998         ret = 0;
2999  out:
3000         mutex_unlock(&event_mutex);
3001
3002         if (ret)
3003                 file = ERR_PTR(ret);
3004
3005         return file;
3006 }
3007 EXPORT_SYMBOL_GPL(trace_get_event_file);
3008
3009 /**
3010  * trace_put_event_file - Release a file from trace_get_event_file()
3011  * @file: The trace event file
3012  *
3013  * If a file was retrieved using trace_get_event_file(), this should
3014  * be called when it's no longer needed.  It will cancel the previous
3015  * trace_array_get() called by that function, and decrement the
3016  * event's module refcount.
3017  */
3018 void trace_put_event_file(struct trace_event_file *file)
3019 {
3020         mutex_lock(&event_mutex);
3021         trace_event_put_ref(file->event_call);
3022         mutex_unlock(&event_mutex);
3023
3024         trace_array_put(file->tr);
3025 }
3026 EXPORT_SYMBOL_GPL(trace_put_event_file);
3027
3028 #ifdef CONFIG_DYNAMIC_FTRACE
3029
3030 /* Avoid typos */
3031 #define ENABLE_EVENT_STR        "enable_event"
3032 #define DISABLE_EVENT_STR       "disable_event"
3033
3034 struct event_probe_data {
3035         struct trace_event_file *file;
3036         unsigned long                   count;
3037         int                             ref;
3038         bool                            enable;
3039 };
3040
3041 static void update_event_probe(struct event_probe_data *data)
3042 {
3043         if (data->enable)
3044                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3045         else
3046                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3047 }
3048
3049 static void
3050 event_enable_probe(unsigned long ip, unsigned long parent_ip,
3051                    struct trace_array *tr, struct ftrace_probe_ops *ops,
3052                    void *data)
3053 {
3054         struct ftrace_func_mapper *mapper = data;
3055         struct event_probe_data *edata;
3056         void **pdata;
3057
3058         pdata = ftrace_func_mapper_find_ip(mapper, ip);
3059         if (!pdata || !*pdata)
3060                 return;
3061
3062         edata = *pdata;
3063         update_event_probe(edata);
3064 }
3065
3066 static void
3067 event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
3068                          struct trace_array *tr, struct ftrace_probe_ops *ops,
3069                          void *data)
3070 {
3071         struct ftrace_func_mapper *mapper = data;
3072         struct event_probe_data *edata;
3073         void **pdata;
3074
3075         pdata = ftrace_func_mapper_find_ip(mapper, ip);
3076         if (!pdata || !*pdata)
3077                 return;
3078
3079         edata = *pdata;
3080
3081         if (!edata->count)
3082                 return;
3083
3084         /* Skip if the event is in a state we want to switch to */
3085         if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
3086                 return;
3087
3088         if (edata->count != -1)
3089                 (edata->count)--;
3090
3091         update_event_probe(edata);
3092 }
3093
3094 static int
3095 event_enable_print(struct seq_file *m, unsigned long ip,
3096                    struct ftrace_probe_ops *ops, void *data)
3097 {
3098         struct ftrace_func_mapper *mapper = data;
3099         struct event_probe_data *edata;
3100         void **pdata;
3101
3102         pdata = ftrace_func_mapper_find_ip(mapper, ip);
3103
3104         if (WARN_ON_ONCE(!pdata || !*pdata))
3105                 return 0;
3106
3107         edata = *pdata;
3108
3109         seq_printf(m, "%ps:", (void *)ip);
3110
3111         seq_printf(m, "%s:%s:%s",
3112                    edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
3113                    edata->file->event_call->class->system,
3114                    trace_event_name(edata->file->event_call));
3115
3116         if (edata->count == -1)
3117                 seq_puts(m, ":unlimited\n");
3118         else
3119                 seq_printf(m, ":count=%ld\n", edata->count);
3120
3121         return 0;
3122 }
3123
3124 static int
3125 event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
3126                   unsigned long ip, void *init_data, void **data)
3127 {
3128         struct ftrace_func_mapper *mapper = *data;
3129         struct event_probe_data *edata = init_data;
3130         int ret;
3131
3132         if (!mapper) {
3133                 mapper = allocate_ftrace_func_mapper();
3134                 if (!mapper)
3135                         return -ENODEV;
3136                 *data = mapper;
3137         }
3138
3139         ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
3140         if (ret < 0)
3141                 return ret;
3142
3143         edata->ref++;
3144
3145         return 0;
3146 }
3147
3148 static int free_probe_data(void *data)
3149 {
3150         struct event_probe_data *edata = data;
3151
3152         edata->ref--;
3153         if (!edata->ref) {
3154                 /* Remove the SOFT_MODE flag */
3155                 __ftrace_event_enable_disable(edata->file, 0, 1);
3156                 trace_event_put_ref(edata->file->event_call);
3157                 kfree(edata);
3158         }
3159         return 0;
3160 }
3161
3162 static void
3163 event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
3164                   unsigned long ip, void *data)
3165 {
3166         struct ftrace_func_mapper *mapper = data;
3167         struct event_probe_data *edata;
3168
3169         if (!ip) {
3170                 if (!mapper)
3171                         return;
3172                 free_ftrace_func_mapper(mapper, free_probe_data);
3173                 return;
3174         }
3175
3176         edata = ftrace_func_mapper_remove_ip(mapper, ip);
3177
3178         if (WARN_ON_ONCE(!edata))
3179                 return;
3180
3181         if (WARN_ON_ONCE(edata->ref <= 0))
3182                 return;
3183
3184         free_probe_data(edata);
3185 }
3186
3187 static struct ftrace_probe_ops event_enable_probe_ops = {
3188         .func                   = event_enable_probe,
3189         .print                  = event_enable_print,
3190         .init                   = event_enable_init,
3191         .free                   = event_enable_free,
3192 };
3193
3194 static struct ftrace_probe_ops event_enable_count_probe_ops = {
3195         .func                   = event_enable_count_probe,
3196         .print                  = event_enable_print,
3197         .init                   = event_enable_init,
3198         .free                   = event_enable_free,
3199 };
3200
3201 static struct ftrace_probe_ops event_disable_probe_ops = {
3202         .func                   = event_enable_probe,
3203         .print                  = event_enable_print,
3204         .init                   = event_enable_init,
3205         .free                   = event_enable_free,
3206 };
3207
3208 static struct ftrace_probe_ops event_disable_count_probe_ops = {
3209         .func                   = event_enable_count_probe,
3210         .print                  = event_enable_print,
3211         .init                   = event_enable_init,
3212         .free                   = event_enable_free,
3213 };
3214
3215 static int
3216 event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
3217                   char *glob, char *cmd, char *param, int enabled)
3218 {
3219         struct trace_event_file *file;
3220         struct ftrace_probe_ops *ops;
3221         struct event_probe_data *data;
3222         const char *system;
3223         const char *event;
3224         char *number;
3225         bool enable;
3226         int ret;
3227
3228         if (!tr)
3229                 return -ENODEV;
3230
3231         /* hash funcs only work with set_ftrace_filter */
3232         if (!enabled || !param)
3233                 return -EINVAL;
3234
3235         system = strsep(&param, ":");
3236         if (!param)
3237                 return -EINVAL;
3238
3239         event = strsep(&param, ":");
3240
3241         mutex_lock(&event_mutex);
3242
3243         ret = -EINVAL;
3244         file = find_event_file(tr, system, event);
3245         if (!file)
3246                 goto out;
3247
3248         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
3249
3250         if (enable)
3251                 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
3252         else
3253                 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
3254
3255         if (glob[0] == '!') {
3256                 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
3257                 goto out;
3258         }
3259
3260         ret = -ENOMEM;
3261
3262         data = kzalloc(sizeof(*data), GFP_KERNEL);
3263         if (!data)
3264                 goto out;
3265
3266         data->enable = enable;
3267         data->count = -1;
3268         data->file = file;
3269
3270         if (!param)
3271                 goto out_reg;
3272
3273         number = strsep(&param, ":");
3274
3275         ret = -EINVAL;
3276         if (!strlen(number))
3277                 goto out_free;
3278
3279         /*
3280          * We use the callback data field (which is a pointer)
3281          * as our counter.
3282          */
3283         ret = kstrtoul(number, 0, &data->count);
3284         if (ret)
3285                 goto out_free;
3286
3287  out_reg:
3288         /* Don't let event modules unload while probe registered */
3289         ret = trace_event_try_get_ref(file->event_call);
3290         if (!ret) {
3291                 ret = -EBUSY;
3292                 goto out_free;
3293         }
3294
3295         ret = __ftrace_event_enable_disable(file, 1, 1);
3296         if (ret < 0)
3297                 goto out_put;
3298
3299         ret = register_ftrace_function_probe(glob, tr, ops, data);
3300         /*
3301          * The above returns on success the # of functions enabled,
3302          * but if it didn't find any functions it returns zero.
3303          * Consider no functions a failure too.
3304          */
3305         if (!ret) {
3306                 ret = -ENOENT;
3307                 goto out_disable;
3308         } else if (ret < 0)
3309                 goto out_disable;
3310         /* Just return zero, not the number of enabled functions */
3311         ret = 0;
3312  out:
3313         mutex_unlock(&event_mutex);
3314         return ret;
3315
3316  out_disable:
3317         __ftrace_event_enable_disable(file, 0, 1);
3318  out_put:
3319         trace_event_put_ref(file->event_call);
3320  out_free:
3321         kfree(data);
3322         goto out;
3323 }
3324
3325 static struct ftrace_func_command event_enable_cmd = {
3326         .name                   = ENABLE_EVENT_STR,
3327         .func                   = event_enable_func,
3328 };
3329
3330 static struct ftrace_func_command event_disable_cmd = {
3331         .name                   = DISABLE_EVENT_STR,
3332         .func                   = event_enable_func,
3333 };
3334
3335 static __init int register_event_cmds(void)
3336 {
3337         int ret;
3338
3339         ret = register_ftrace_command(&event_enable_cmd);
3340         if (WARN_ON(ret < 0))
3341                 return ret;
3342         ret = register_ftrace_command(&event_disable_cmd);
3343         if (WARN_ON(ret < 0))
3344                 unregister_ftrace_command(&event_enable_cmd);
3345         return ret;
3346 }
3347 #else
3348 static inline int register_event_cmds(void) { return 0; }
3349 #endif /* CONFIG_DYNAMIC_FTRACE */
3350
3351 /*
3352  * The top level array and trace arrays created by boot-time tracing
3353  * have already had its trace_event_file descriptors created in order
3354  * to allow for early events to be recorded.
3355  * This function is called after the tracefs has been initialized,
3356  * and we now have to create the files associated to the events.
3357  */
3358 static void __trace_early_add_event_dirs(struct trace_array *tr)
3359 {
3360         struct trace_event_file *file;
3361         int ret;
3362
3363
3364         list_for_each_entry(file, &tr->events, list) {
3365                 ret = event_create_dir(tr->event_dir, file);
3366                 if (ret < 0)
3367                         pr_warn("Could not create directory for event %s\n",
3368                                 trace_event_name(file->event_call));
3369         }
3370 }
3371
3372 /*
3373  * For early boot up, the top trace array and the trace arrays created
3374  * by boot-time tracing require to have a list of events that can be
3375  * enabled. This must be done before the filesystem is set up in order
3376  * to allow events to be traced early.
3377  */
3378 void __trace_early_add_events(struct trace_array *tr)
3379 {
3380         struct trace_event_call *call;
3381         int ret;
3382
3383         list_for_each_entry(call, &ftrace_events, list) {
3384                 /* Early boot up should not have any modules loaded */
3385                 if (!(call->flags & TRACE_EVENT_FL_DYNAMIC) &&
3386                     WARN_ON_ONCE(call->module))
3387                         continue;
3388
3389                 ret = __trace_early_add_new_event(call, tr);
3390                 if (ret < 0)
3391                         pr_warn("Could not create early event %s\n",
3392                                 trace_event_name(call));
3393         }
3394 }
3395
3396 /* Remove the event directory structure for a trace directory. */
3397 static void
3398 __trace_remove_event_dirs(struct trace_array *tr)
3399 {
3400         struct trace_event_file *file, *next;
3401
3402         list_for_each_entry_safe(file, next, &tr->events, list)
3403                 remove_event_file_dir(file);
3404 }
3405
3406 static void __add_event_to_tracers(struct trace_event_call *call)
3407 {
3408         struct trace_array *tr;
3409
3410         list_for_each_entry(tr, &ftrace_trace_arrays, list)
3411                 __trace_add_new_event(call, tr);
3412 }
3413
3414 extern struct trace_event_call *__start_ftrace_events[];
3415 extern struct trace_event_call *__stop_ftrace_events[];
3416
3417 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
3418
3419 static __init int setup_trace_event(char *str)
3420 {
3421         strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
3422         ring_buffer_expanded = true;
3423         disable_tracing_selftest("running event tracing");
3424
3425         return 1;
3426 }
3427 __setup("trace_event=", setup_trace_event);
3428
3429 /* Expects to have event_mutex held when called */
3430 static int
3431 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
3432 {
3433         struct dentry *d_events;
3434         struct dentry *entry;
3435
3436         entry = tracefs_create_file("set_event", 0644, parent,
3437                                     tr, &ftrace_set_event_fops);
3438         if (!entry) {
3439                 pr_warn("Could not create tracefs 'set_event' entry\n");
3440                 return -ENOMEM;
3441         }
3442
3443         d_events = tracefs_create_dir("events", parent);
3444         if (!d_events) {
3445                 pr_warn("Could not create tracefs 'events' directory\n");
3446                 return -ENOMEM;
3447         }
3448
3449         entry = trace_create_file("enable", 0644, d_events,
3450                                   tr, &ftrace_tr_enable_fops);
3451         if (!entry) {
3452                 pr_warn("Could not create tracefs 'enable' entry\n");
3453                 return -ENOMEM;
3454         }
3455
3456         /* There are not as crucial, just warn if they are not created */
3457
3458         entry = tracefs_create_file("set_event_pid", 0644, parent,
3459                                     tr, &ftrace_set_event_pid_fops);
3460         if (!entry)
3461                 pr_warn("Could not create tracefs 'set_event_pid' entry\n");
3462
3463         entry = tracefs_create_file("set_event_notrace_pid", 0644, parent,
3464                                     tr, &ftrace_set_event_notrace_pid_fops);
3465         if (!entry)
3466                 pr_warn("Could not create tracefs 'set_event_notrace_pid' entry\n");
3467
3468         /* ring buffer internal formats */
3469         entry = trace_create_file("header_page", 0444, d_events,
3470                                   ring_buffer_print_page_header,
3471                                   &ftrace_show_header_fops);
3472         if (!entry)
3473                 pr_warn("Could not create tracefs 'header_page' entry\n");
3474
3475         entry = trace_create_file("header_event", 0444, d_events,
3476                                   ring_buffer_print_entry_header,
3477                                   &ftrace_show_header_fops);
3478         if (!entry)
3479                 pr_warn("Could not create tracefs 'header_event' entry\n");
3480
3481         tr->event_dir = d_events;
3482
3483         return 0;
3484 }
3485
3486 /**
3487  * event_trace_add_tracer - add a instance of a trace_array to events
3488  * @parent: The parent dentry to place the files/directories for events in
3489  * @tr: The trace array associated with these events
3490  *
3491  * When a new instance is created, it needs to set up its events
3492  * directory, as well as other files associated with events. It also
3493  * creates the event hierarchy in the @parent/events directory.
3494  *
3495  * Returns 0 on success.
3496  *
3497  * Must be called with event_mutex held.
3498  */
3499 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
3500 {
3501         int ret;
3502
3503         lockdep_assert_held(&event_mutex);
3504
3505         ret = create_event_toplevel_files(parent, tr);
3506         if (ret)
3507                 goto out;
3508
3509         down_write(&trace_event_sem);
3510         /* If tr already has the event list, it is initialized in early boot. */
3511         if (unlikely(!list_empty(&tr->events)))
3512                 __trace_early_add_event_dirs(tr);
3513         else
3514                 __trace_add_event_dirs(tr);
3515         up_write(&trace_event_sem);
3516
3517  out:
3518         return ret;
3519 }
3520
3521 /*
3522  * The top trace array already had its file descriptors created.
3523  * Now the files themselves need to be created.
3524  */
3525 static __init int
3526 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
3527 {
3528         int ret;
3529
3530         mutex_lock(&event_mutex);
3531
3532         ret = create_event_toplevel_files(parent, tr);
3533         if (ret)
3534                 goto out_unlock;
3535
3536         down_write(&trace_event_sem);
3537         __trace_early_add_event_dirs(tr);
3538         up_write(&trace_event_sem);
3539
3540  out_unlock:
3541         mutex_unlock(&event_mutex);
3542
3543         return ret;
3544 }
3545
3546 /* Must be called with event_mutex held */
3547 int event_trace_del_tracer(struct trace_array *tr)
3548 {
3549         lockdep_assert_held(&event_mutex);
3550
3551         /* Disable any event triggers and associated soft-disabled events */
3552         clear_event_triggers(tr);
3553
3554         /* Clear the pid list */
3555         __ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
3556
3557         /* Disable any running events */
3558         __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3559
3560         /* Make sure no more events are being executed */
3561         tracepoint_synchronize_unregister();
3562
3563         down_write(&trace_event_sem);
3564         __trace_remove_event_dirs(tr);
3565         tracefs_remove(tr->event_dir);
3566         up_write(&trace_event_sem);
3567
3568         tr->event_dir = NULL;
3569
3570         return 0;
3571 }
3572
3573 static __init int event_trace_memsetup(void)
3574 {
3575         field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3576         file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3577         return 0;
3578 }
3579
3580 static __init void
3581 early_enable_events(struct trace_array *tr, bool disable_first)
3582 {
3583         char *buf = bootup_event_buf;
3584         char *token;
3585         int ret;
3586
3587         while (true) {
3588                 token = strsep(&buf, ",");
3589
3590                 if (!token)
3591                         break;
3592
3593                 if (*token) {
3594                         /* Restarting syscalls requires that we stop them first */
3595                         if (disable_first)
3596                                 ftrace_set_clr_event(tr, token, 0);
3597
3598                         ret = ftrace_set_clr_event(tr, token, 1);
3599                         if (ret)
3600                                 pr_warn("Failed to enable trace event: %s\n", token);
3601                 }
3602
3603                 /* Put back the comma to allow this to be called again */
3604                 if (buf)
3605                         *(buf - 1) = ',';
3606         }
3607 }
3608
3609 static __init int event_trace_enable(void)
3610 {
3611         struct trace_array *tr = top_trace_array();
3612         struct trace_event_call **iter, *call;
3613         int ret;
3614
3615         if (!tr)
3616                 return -ENODEV;
3617
3618         for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3619
3620                 call = *iter;
3621                 ret = event_init(call);
3622                 if (!ret)
3623                         list_add(&call->list, &ftrace_events);
3624         }
3625
3626         /*
3627          * We need the top trace array to have a working set of trace
3628          * points at early init, before the debug files and directories
3629          * are created. Create the file entries now, and attach them
3630          * to the actual file dentries later.
3631          */
3632         __trace_early_add_events(tr);
3633
3634         early_enable_events(tr, false);
3635
3636         trace_printk_start_comm();
3637
3638         register_event_cmds();
3639
3640         register_trigger_cmds();
3641
3642         return 0;
3643 }
3644
3645 /*
3646  * event_trace_enable() is called from trace_event_init() first to
3647  * initialize events and perhaps start any events that are on the
3648  * command line. Unfortunately, there are some events that will not
3649  * start this early, like the system call tracepoints that need
3650  * to set the %SYSCALL_WORK_SYSCALL_TRACEPOINT flag of pid 1. But
3651  * event_trace_enable() is called before pid 1 starts, and this flag
3652  * is never set, making the syscall tracepoint never get reached, but
3653  * the event is enabled regardless (and not doing anything).
3654  */
3655 static __init int event_trace_enable_again(void)
3656 {
3657         struct trace_array *tr;
3658
3659         tr = top_trace_array();
3660         if (!tr)
3661                 return -ENODEV;
3662
3663         early_enable_events(tr, true);
3664
3665         return 0;
3666 }
3667
3668 early_initcall(event_trace_enable_again);
3669
3670 /* Init fields which doesn't related to the tracefs */
3671 static __init int event_trace_init_fields(void)
3672 {
3673         if (trace_define_generic_fields())
3674                 pr_warn("tracing: Failed to allocated generic fields");
3675
3676         if (trace_define_common_fields())
3677                 pr_warn("tracing: Failed to allocate common fields");
3678
3679         return 0;
3680 }
3681
3682 __init int event_trace_init(void)
3683 {
3684         struct trace_array *tr;
3685         struct dentry *entry;
3686         int ret;
3687
3688         tr = top_trace_array();
3689         if (!tr)
3690                 return -ENODEV;
3691
3692         entry = tracefs_create_file("available_events", 0444, NULL,
3693                                     tr, &ftrace_avail_fops);
3694         if (!entry)
3695                 pr_warn("Could not create tracefs 'available_events' entry\n");
3696
3697         ret = early_event_add_tracer(NULL, tr);
3698         if (ret)
3699                 return ret;
3700
3701 #ifdef CONFIG_MODULES
3702         ret = register_module_notifier(&trace_module_nb);
3703         if (ret)
3704                 pr_warn("Failed to register trace events module notifier\n");
3705 #endif
3706
3707         eventdir_initialized = true;
3708
3709         return 0;
3710 }
3711
3712 void __init trace_event_init(void)
3713 {
3714         event_trace_memsetup();
3715         init_ftrace_syscalls();
3716         event_trace_enable();
3717         event_trace_init_fields();
3718 }
3719
3720 #ifdef CONFIG_EVENT_TRACE_STARTUP_TEST
3721
3722 static DEFINE_SPINLOCK(test_spinlock);
3723 static DEFINE_SPINLOCK(test_spinlock_irq);
3724 static DEFINE_MUTEX(test_mutex);
3725
3726 static __init void test_work(struct work_struct *dummy)
3727 {
3728         spin_lock(&test_spinlock);
3729         spin_lock_irq(&test_spinlock_irq);
3730         udelay(1);
3731         spin_unlock_irq(&test_spinlock_irq);
3732         spin_unlock(&test_spinlock);
3733
3734         mutex_lock(&test_mutex);
3735         msleep(1);
3736         mutex_unlock(&test_mutex);
3737 }
3738
3739 static __init int event_test_thread(void *unused)
3740 {
3741         void *test_malloc;
3742
3743         test_malloc = kmalloc(1234, GFP_KERNEL);
3744         if (!test_malloc)
3745                 pr_info("failed to kmalloc\n");
3746
3747         schedule_on_each_cpu(test_work);
3748
3749         kfree(test_malloc);
3750
3751         set_current_state(TASK_INTERRUPTIBLE);
3752         while (!kthread_should_stop()) {
3753                 schedule();
3754                 set_current_state(TASK_INTERRUPTIBLE);
3755         }
3756         __set_current_state(TASK_RUNNING);
3757
3758         return 0;
3759 }
3760
3761 /*
3762  * Do various things that may trigger events.
3763  */
3764 static __init void event_test_stuff(void)
3765 {
3766         struct task_struct *test_thread;
3767
3768         test_thread = kthread_run(event_test_thread, NULL, "test-events");
3769         msleep(1);
3770         kthread_stop(test_thread);
3771 }
3772
3773 /*
3774  * For every trace event defined, we will test each trace point separately,
3775  * and then by groups, and finally all trace points.
3776  */
3777 static __init void event_trace_self_tests(void)
3778 {
3779         struct trace_subsystem_dir *dir;
3780         struct trace_event_file *file;
3781         struct trace_event_call *call;
3782         struct event_subsystem *system;
3783         struct trace_array *tr;
3784         int ret;
3785
3786         tr = top_trace_array();
3787         if (!tr)
3788                 return;
3789
3790         pr_info("Running tests on trace events:\n");
3791
3792         list_for_each_entry(file, &tr->events, list) {
3793
3794                 call = file->event_call;
3795
3796                 /* Only test those that have a probe */
3797                 if (!call->class || !call->class->probe)
3798                         continue;
3799
3800 /*
3801  * Testing syscall events here is pretty useless, but
3802  * we still do it if configured. But this is time consuming.
3803  * What we really need is a user thread to perform the
3804  * syscalls as we test.
3805  */
3806 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
3807                 if (call->class->system &&
3808                     strcmp(call->class->system, "syscalls") == 0)
3809                         continue;
3810 #endif
3811
3812                 pr_info("Testing event %s: ", trace_event_name(call));
3813
3814                 /*
3815                  * If an event is already enabled, someone is using
3816                  * it and the self test should not be on.
3817                  */
3818                 if (file->flags & EVENT_FILE_FL_ENABLED) {
3819                         pr_warn("Enabled event during self test!\n");
3820                         WARN_ON_ONCE(1);
3821                         continue;
3822                 }
3823
3824                 ftrace_event_enable_disable(file, 1);
3825                 event_test_stuff();
3826                 ftrace_event_enable_disable(file, 0);
3827
3828                 pr_cont("OK\n");
3829         }
3830
3831         /* Now test at the sub system level */
3832
3833         pr_info("Running tests on trace event systems:\n");
3834
3835         list_for_each_entry(dir, &tr->systems, list) {
3836
3837                 system = dir->subsystem;
3838
3839                 /* the ftrace system is special, skip it */
3840                 if (strcmp(system->name, "ftrace") == 0)
3841                         continue;
3842
3843                 pr_info("Testing event system %s: ", system->name);
3844
3845                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
3846                 if (WARN_ON_ONCE(ret)) {
3847                         pr_warn("error enabling system %s\n",
3848                                 system->name);
3849                         continue;
3850                 }
3851
3852                 event_test_stuff();
3853
3854                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
3855                 if (WARN_ON_ONCE(ret)) {
3856                         pr_warn("error disabling system %s\n",
3857                                 system->name);
3858                         continue;
3859                 }
3860
3861                 pr_cont("OK\n");
3862         }
3863
3864         /* Test with all events enabled */
3865
3866         pr_info("Running tests on all trace events:\n");
3867         pr_info("Testing all events: ");
3868
3869         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
3870         if (WARN_ON_ONCE(ret)) {
3871                 pr_warn("error enabling all events\n");
3872                 return;
3873         }
3874
3875         event_test_stuff();
3876
3877         /* reset sysname */
3878         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
3879         if (WARN_ON_ONCE(ret)) {
3880                 pr_warn("error disabling all events\n");
3881                 return;
3882         }
3883
3884         pr_cont("OK\n");
3885 }
3886
3887 #ifdef CONFIG_FUNCTION_TRACER
3888
3889 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
3890
3891 static struct trace_event_file event_trace_file __initdata;
3892
3893 static void __init
3894 function_test_events_call(unsigned long ip, unsigned long parent_ip,
3895                           struct ftrace_ops *op, struct ftrace_regs *regs)
3896 {
3897         struct trace_buffer *buffer;
3898         struct ring_buffer_event *event;
3899         struct ftrace_entry *entry;
3900         unsigned int trace_ctx;
3901         long disabled;
3902         int cpu;
3903
3904         trace_ctx = tracing_gen_ctx();
3905         preempt_disable_notrace();
3906         cpu = raw_smp_processor_id();
3907         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
3908
3909         if (disabled != 1)
3910                 goto out;
3911
3912         event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
3913                                                 TRACE_FN, sizeof(*entry),
3914                                                 trace_ctx);
3915         if (!event)
3916                 goto out;
3917         entry   = ring_buffer_event_data(event);
3918         entry->ip                       = ip;
3919         entry->parent_ip                = parent_ip;
3920
3921         event_trigger_unlock_commit(&event_trace_file, buffer, event,
3922                                     entry, trace_ctx);
3923  out:
3924         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
3925         preempt_enable_notrace();
3926 }
3927
3928 static struct ftrace_ops trace_ops __initdata  =
3929 {
3930         .func = function_test_events_call,
3931 };
3932
3933 static __init void event_trace_self_test_with_function(void)
3934 {
3935         int ret;
3936
3937         event_trace_file.tr = top_trace_array();
3938         if (WARN_ON(!event_trace_file.tr))
3939                 return;
3940
3941         ret = register_ftrace_function(&trace_ops);
3942         if (WARN_ON(ret < 0)) {
3943                 pr_info("Failed to enable function tracer for event tests\n");
3944                 return;
3945         }
3946         pr_info("Running tests again, along with the function tracer\n");
3947         event_trace_self_tests();
3948         unregister_ftrace_function(&trace_ops);
3949 }
3950 #else
3951 static __init void event_trace_self_test_with_function(void)
3952 {
3953 }
3954 #endif
3955
3956 static __init int event_trace_self_tests_init(void)
3957 {
3958         if (!tracing_selftest_disabled) {
3959                 event_trace_self_tests();
3960                 event_trace_self_test_with_function();
3961         }
3962
3963         return 0;
3964 }
3965
3966 late_initcall(event_trace_self_tests_init);
3967
3968 #endif