kernel/trace/trace_events.c

   1 /*
   2  * event tracer
   3  *
   4  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
   5  *
   6  *  - Added format output of fields of the trace point.
   7  *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
   8  *
   9  */
  10
  11 #include <linux/workqueue.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/kthread.h>
  14 #include <linux/debugfs.h>
  15 #include <linux/uaccess.h>
  16 #include <linux/module.h>
  17 #include <linux/ctype.h>
  18 #include <linux/slab.h>
  19 #include <linux/delay.h>
  20
  21 #include <asm/setup.h>
  22
  23 #include "trace_output.h"
  24
  25 #undef TRACE_SYSTEM
  26 #define TRACE_SYSTEM "TRACE_SYSTEM"
  27
  28 DEFINE_MUTEX(event_mutex);
  29
  30 DEFINE_MUTEX(event_storage_mutex);
  31 EXPORT_SYMBOL_GPL(event_storage_mutex);
  32
  33 char event_storage[EVENT_STORAGE_SIZE];
  34 EXPORT_SYMBOL_GPL(event_storage);
  35
  36 LIST_HEAD(ftrace_events);
  37 LIST_HEAD(ftrace_common_fields);
  38
  39 struct list_head *
  40 trace_get_fields(struct ftrace_event_call *event_call)
  41 {
  42         if (!event_call->class->get_fields)
  43                 return &event_call->class->fields;
  44         return event_call->class->get_fields(event_call);
  45 }
  46
  47 static int __trace_define_field(struct list_head *head, const char *type,
  48                                 const char *name, int offset, int size,
  49                                 int is_signed, int filter_type)
  50 {
  51         struct ftrace_event_field *field;
  52
  53         field = kzalloc(sizeof(*field), GFP_KERNEL);
  54         if (!field)
  55                 goto err;
  56
  57         field->name = kstrdup(name, GFP_KERNEL);
  58         if (!field->name)
  59                 goto err;
  60
  61         field->type = kstrdup(type, GFP_KERNEL);
  62         if (!field->type)
  63                 goto err;
  64
  65         if (filter_type == FILTER_OTHER)
  66                 field->filter_type = filter_assign_type(type);
  67         else
  68                 field->filter_type = filter_type;
  69
  70         field->offset = offset;
  71         field->size = size;
  72         field->is_signed = is_signed;
  73
  74         list_add(&field->link, head);
  75
  76         return 0;
  77
  78 err:
  79         if (field)
  80                 kfree(field->name);
  81         kfree(field);
  82
  83         return -ENOMEM;
  84 }
  85
  86 int trace_define_field(struct ftrace_event_call *call, const char *type,
  87                        const char *name, int offset, int size, int is_signed,
  88                        int filter_type)
  89 {
  90         struct list_head *head;
  91
  92         if (WARN_ON(!call->class))
  93                 return 0;
  94
  95         head = trace_get_fields(call);
  96         return __trace_define_field(head, type, name, offset, size,
  97                                     is_signed, filter_type);
  98 }
  99 EXPORT_SYMBOL_GPL(trace_define_field);
 100
 101 #define __common_field(type, item)                                      \
 102         ret = __trace_define_field(&ftrace_common_fields, #type,        \
 103                                    "common_" #item,                     \
 104                                    offsetof(typeof(ent), item),         \
 105                                    sizeof(ent.item),                    \
 106                                    is_signed_type(type), FILTER_OTHER); \
 107         if (ret)                                                        \
 108                 return ret;
 109
 110 static int trace_define_common_fields(void)
 111 {
 112         int ret;
 113         struct trace_entry ent;
 114
 115         __common_field(unsigned short, type);
 116         __common_field(unsigned char, flags);
 117         __common_field(unsigned char, preempt_count);
 118         __common_field(int, pid);
 119         __common_field(int, padding);
 120
 121         return ret;
 122 }
 123
 124 void trace_destroy_fields(struct ftrace_event_call *call)
 125 {
 126         struct ftrace_event_field *field, *next;
 127         struct list_head *head;
 128
 129         head = trace_get_fields(call);
 130         list_for_each_entry_safe(field, next, head, link) {
 131                 list_del(&field->link);
 132                 kfree(field->type);
 133                 kfree(field->name);
 134                 kfree(field);
 135         }
 136 }
 137
 138 int trace_event_raw_init(struct ftrace_event_call *call)
 139 {
 140         int id;
 141
 142         id = register_ftrace_event(&call->event);
 143         if (!id)
 144                 return -ENODEV;
 145
 146         return 0;
 147 }
 148 EXPORT_SYMBOL_GPL(trace_event_raw_init);
 149
 150 int ftrace_event_reg(struct ftrace_event_call *call, enum trace_reg type)
 151 {
 152         switch (type) {
 153         case TRACE_REG_REGISTER:
 154                 return tracepoint_probe_register(call->name,
 155                                                  call->class->probe,
 156                                                  call);
 157         case TRACE_REG_UNREGISTER:
 158                 tracepoint_probe_unregister(call->name,
 159                                             call->class->probe,
 160                                             call);
 161                 return 0;
 162
 163 #ifdef CONFIG_PERF_EVENTS
 164         case TRACE_REG_PERF_REGISTER:
 165                 return tracepoint_probe_register(call->name,
 166                                                  call->class->perf_probe,
 167                                                  call);
 168         case TRACE_REG_PERF_UNREGISTER:
 169                 tracepoint_probe_unregister(call->name,
 170                                             call->class->perf_probe,
 171                                             call);
 172                 return 0;
 173 #endif
 174         }
 175         return 0;
 176 }
 177 EXPORT_SYMBOL_GPL(ftrace_event_reg);
 178
 179 void trace_event_enable_cmd_record(bool enable)
 180 {
 181         struct ftrace_event_call *call;
 182
 183         mutex_lock(&event_mutex);
 184         list_for_each_entry(call, &ftrace_events, list) {
 185                 if (!(call->flags & TRACE_EVENT_FL_ENABLED))
 186                         continue;
 187
 188                 if (enable) {
 189                         tracing_start_cmdline_record();
 190                         call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
 191                 } else {
 192                         tracing_stop_cmdline_record();
 193                         call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
 194                 }
 195         }
 196         mutex_unlock(&event_mutex);
 197 }
 198
 199 static int ftrace_event_enable_disable(struct ftrace_event_call *call,
 200                                         int enable)
 201 {
 202         int ret = 0;
 203
 204         switch (enable) {
 205         case 0:
 206                 if (call->flags & TRACE_EVENT_FL_ENABLED) {
 207                         call->flags &= ~TRACE_EVENT_FL_ENABLED;
 208                         if (call->flags & TRACE_EVENT_FL_RECORDED_CMD) {
 209                                 tracing_stop_cmdline_record();
 210                                 call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
 211                         }
 212                         call->class->reg(call, TRACE_REG_UNREGISTER);
 213                 }
 214                 break;
 215         case 1:
 216                 if (!(call->flags & TRACE_EVENT_FL_ENABLED)) {
 217                         if (trace_flags & TRACE_ITER_RECORD_CMD) {
 218                                 tracing_start_cmdline_record();
 219                                 call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
 220                         }
 221                         ret = call->class->reg(call, TRACE_REG_REGISTER);
 222                         if (ret) {
 223                                 tracing_stop_cmdline_record();
 224                                 pr_info("event trace: Could not enable event "
 225                                         "%s\n", call->name);
 226                                 break;
 227                         }
 228                         call->flags |= TRACE_EVENT_FL_ENABLED;
 229                 }
 230                 break;
 231         }
 232
 233         return ret;
 234 }
 235
 236 static void ftrace_clear_events(void)
 237 {
 238         struct ftrace_event_call *call;
 239
 240         mutex_lock(&event_mutex);
 241         list_for_each_entry(call, &ftrace_events, list) {
 242                 ftrace_event_enable_disable(call, 0);
 243         }
 244         mutex_unlock(&event_mutex);
 245 }
 246
 247 static void __put_system(struct event_subsystem *system)
 248 {
 249         struct event_filter *filter = system->filter;
 250
 251         WARN_ON_ONCE(system->ref_count == 0);
 252         if (--system->ref_count)
 253                 return;
 254
 255         if (filter) {
 256                 kfree(filter->filter_string);
 257                 kfree(filter);
 258         }
 259         kfree(system->name);
 260         kfree(system);
 261 }
 262
 263 static void __get_system(struct event_subsystem *system)
 264 {
 265         WARN_ON_ONCE(system->ref_count == 0);
 266         system->ref_count++;
 267 }
 268
 269 static void put_system(struct event_subsystem *system)
 270 {
 271         mutex_lock(&event_mutex);
 272         __put_system(system);
 273         mutex_unlock(&event_mutex);
 274 }
 275
 276 /*
 277  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
 278  */
 279 static int __ftrace_set_clr_event(const char *match, const char *sub,
 280                                   const char *event, int set)
 281 {
 282         struct ftrace_event_call *call;
 283         int ret = -EINVAL;
 284
 285         mutex_lock(&event_mutex);
 286         list_for_each_entry(call, &ftrace_events, list) {
 287
 288                 if (!call->name || !call->class || !call->class->reg)
 289                         continue;
 290
 291                 if (match &&
 292                     strcmp(match, call->name) != 0 &&
 293                     strcmp(match, call->class->system) != 0)
 294                         continue;
 295
 296                 if (sub && strcmp(sub, call->class->system) != 0)
 297                         continue;
 298
 299                 if (event && strcmp(event, call->name) != 0)
 300                         continue;
 301
 302                 ftrace_event_enable_disable(call, set);
 303
 304                 ret = 0;
 305         }
 306         mutex_unlock(&event_mutex);
 307
 308         return ret;
 309 }
 310
 311 static int ftrace_set_clr_event(char *buf, int set)
 312 {
 313         char *event = NULL, *sub = NULL, *match;
 314
 315         /*
 316          * The buf format can be <subsystem>:<event-name>
 317          *  *:<event-name> means any event by that name.
 318          *  :<event-name> is the same.
 319          *
 320          *  <subsystem>:* means all events in that subsystem
 321          *  <subsystem>: means the same.
 322          *
 323          *  <name> (no ':') means all events in a subsystem with
 324          *  the name <name> or any event that matches <name>
 325          */
 326
 327         match = strsep(&buf, ":");
 328         if (buf) {
 329                 sub = match;
 330                 event = buf;
 331                 match = NULL;
 332
 333                 if (!strlen(sub) || strcmp(sub, "*") == 0)
 334                         sub = NULL;
 335                 if (!strlen(event) || strcmp(event, "*") == 0)
 336                         event = NULL;
 337         }
 338
 339         return __ftrace_set_clr_event(match, sub, event, set);
 340 }
 341
 342 /**
 343  * trace_set_clr_event - enable or disable an event
 344  * @system: system name to match (NULL for any system)
 345  * @event: event name to match (NULL for all events, within system)
 346  * @set: 1 to enable, 0 to disable
 347  *
 348  * This is a way for other parts of the kernel to enable or disable
 349  * event recording.
 350  *
 351  * Returns 0 on success, -EINVAL if the parameters do not match any
 352  * registered events.
 353  */
 354 int trace_set_clr_event(const char *system, const char *event, int set)
 355 {
 356         return __ftrace_set_clr_event(NULL, system, event, set);
 357 }
 358 EXPORT_SYMBOL_GPL(trace_set_clr_event);
 359
 360 /* 128 should be much more than enough */
 361 #define EVENT_BUF_SIZE          127
 362
 363 static ssize_t
 364 ftrace_event_write(struct file *file, const char __user *ubuf,
 365                    size_t cnt, loff_t *ppos)
 366 {
 367         struct trace_parser parser;
 368         ssize_t read, ret;
 369
 370         if (!cnt)
 371                 return 0;
 372
 373         ret = tracing_update_buffers();
 374         if (ret < 0)
 375                 return ret;
 376
 377         if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
 378                 return -ENOMEM;
 379
 380         read = trace_get_user(&parser, ubuf, cnt, ppos);
 381
 382         if (read >= 0 && trace_parser_loaded((&parser))) {
 383                 int set = 1;
 384
 385                 if (*parser.buffer == '!')
 386                         set = 0;
 387
 388                 parser.buffer[parser.idx] = 0;
 389
 390                 ret = ftrace_set_clr_event(parser.buffer + !set, set);
 391                 if (ret)
 392                         goto out_put;
 393         }
 394
 395         ret = read;
 396
 397  out_put:
 398         trace_parser_put(&parser);
 399
 400         return ret;
 401 }
 402
 403 static void *
 404 t_next(struct seq_file *m, void *v, loff_t *pos)
 405 {
 406         struct ftrace_event_call *call = v;
 407
 408         (*pos)++;
 409
 410         list_for_each_entry_continue(call, &ftrace_events, list) {
 411                 /*
 412                  * The ftrace subsystem is for showing formats only.
 413                  * They can not be enabled or disabled via the event files.
 414                  */
 415                 if (call->class && call->class->reg)
 416                         return call;
 417         }
 418
 419         return NULL;
 420 }
 421
 422 static void *t_start(struct seq_file *m, loff_t *pos)
 423 {
 424         struct ftrace_event_call *call;
 425         loff_t l;
 426
 427         mutex_lock(&event_mutex);
 428
 429         call = list_entry(&ftrace_events, struct ftrace_event_call, list);
 430         for (l = 0; l <= *pos; ) {
 431                 call = t_next(m, call, &l);
 432                 if (!call)
 433                         break;
 434         }
 435         return call;
 436 }
 437
 438 static void *
 439 s_next(struct seq_file *m, void *v, loff_t *pos)
 440 {
 441         struct ftrace_event_call *call = v;
 442
 443         (*pos)++;
 444
 445         list_for_each_entry_continue(call, &ftrace_events, list) {
 446                 if (call->flags & TRACE_EVENT_FL_ENABLED)
 447                         return call;
 448         }
 449
 450         return NULL;
 451 }
 452
 453 static void *s_start(struct seq_file *m, loff_t *pos)
 454 {
 455         struct ftrace_event_call *call;
 456         loff_t l;
 457
 458         mutex_lock(&event_mutex);
 459
 460         call = list_entry(&ftrace_events, struct ftrace_event_call, list);
 461         for (l = 0; l <= *pos; ) {
 462                 call = s_next(m, call, &l);
 463                 if (!call)
 464                         break;
 465         }
 466         return call;
 467 }
 468
 469 static int t_show(struct seq_file *m, void *v)
 470 {
 471         struct ftrace_event_call *call = v;
 472
 473         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
 474                 seq_printf(m, "%s:", call->class->system);
 475         seq_printf(m, "%s\n", call->name);
 476
 477         return 0;
 478 }
 479
 480 static void t_stop(struct seq_file *m, void *p)
 481 {
 482         mutex_unlock(&event_mutex);
 483 }
 484
 485 static int
 486 ftrace_event_seq_open(struct inode *inode, struct file *file)
 487 {
 488         const struct seq_operations *seq_ops;
 489
 490         if ((file->f_mode & FMODE_WRITE) &&
 491             (file->f_flags & O_TRUNC))
 492                 ftrace_clear_events();
 493
 494         seq_ops = inode->i_private;
 495         return seq_open(file, seq_ops);
 496 }
 497
 498 static ssize_t
 499 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
 500                   loff_t *ppos)
 501 {
 502         struct ftrace_event_call *call = filp->private_data;
 503         char *buf;
 504
 505         if (call->flags & TRACE_EVENT_FL_ENABLED)
 506                 buf = "1\n";
 507         else
 508                 buf = "0\n";
 509
 510         return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
 511 }
 512
 513 static ssize_t
 514 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 515                    loff_t *ppos)
 516 {
 517         struct ftrace_event_call *call = filp->private_data;
 518         char buf[64];
 519         unsigned long val;
 520         int ret;
 521
 522         if (cnt >= sizeof(buf))
 523                 return -EINVAL;
 524
 525         if (copy_from_user(&buf, ubuf, cnt))
 526                 return -EFAULT;
 527
 528         buf[cnt] = 0;
 529
 530         ret = strict_strtoul(buf, 10, &val);
 531         if (ret < 0)
 532                 return ret;
 533
 534         ret = tracing_update_buffers();
 535         if (ret < 0)
 536                 return ret;
 537
 538         switch (val) {
 539         case 0:
 540         case 1:
 541                 mutex_lock(&event_mutex);
 542                 ret = ftrace_event_enable_disable(call, val);
 543                 mutex_unlock(&event_mutex);
 544                 break;
 545
 546         default:
 547                 return -EINVAL;
 548         }
 549
 550         *ppos += cnt;
 551
 552         return ret ? ret : cnt;
 553 }
 554
 555 static ssize_t
 556 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
 557                    loff_t *ppos)
 558 {
 559         const char set_to_char[4] = { '?', '0', '1', 'X' };
 560         const char *system = filp->private_data;
 561         struct ftrace_event_call *call;
 562         char buf[2];
 563         int set = 0;
 564         int ret;
 565
 566         mutex_lock(&event_mutex);
 567         list_for_each_entry(call, &ftrace_events, list) {
 568                 if (!call->name || !call->class || !call->class->reg)
 569                         continue;
 570
 571                 if (system && strcmp(call->class->system, system) != 0)
 572                         continue;
 573
 574                 /*
 575                  * We need to find out if all the events are set
 576                  * or if all events or cleared, or if we have
 577                  * a mixture.
 578                  */
 579                 set |= (1 << !!(call->flags & TRACE_EVENT_FL_ENABLED));
 580
 581                 /*
 582                  * If we have a mixture, no need to look further.
 583                  */
 584                 if (set == 3)
 585                         break;
 586         }
 587         mutex_unlock(&event_mutex);
 588
 589         buf[0] = set_to_char[set];
 590         buf[1] = '\n';
 591
 592         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
 593
 594         return ret;
 595 }
 596
 597 static ssize_t
 598 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 599                     loff_t *ppos)
 600 {
 601         const char *system = filp->private_data;
 602         unsigned long val;
 603         char buf[64];
 604         ssize_t ret;
 605
 606         if (cnt >= sizeof(buf))
 607                 return -EINVAL;
 608
 609         if (copy_from_user(&buf, ubuf, cnt))
 610                 return -EFAULT;
 611
 612         buf[cnt] = 0;
 613
 614         ret = strict_strtoul(buf, 10, &val);
 615         if (ret < 0)
 616                 return ret;
 617
 618         ret = tracing_update_buffers();
 619         if (ret < 0)
 620                 return ret;
 621
 622         if (val != 0 && val != 1)
 623                 return -EINVAL;
 624
 625         ret = __ftrace_set_clr_event(NULL, system, NULL, val);
 626         if (ret)
 627                 goto out;
 628
 629         ret = cnt;
 630
 631 out:
 632         *ppos += cnt;
 633
 634         return ret;
 635 }
 636
 637 enum {
 638         FORMAT_HEADER           = 1,
 639         FORMAT_FIELD_SEPERATOR  = 2,
 640         FORMAT_PRINTFMT         = 3,
 641 };
 642
 643 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
 644 {
 645         struct ftrace_event_call *call = m->private;
 646         struct ftrace_event_field *field;
 647         struct list_head *common_head = &ftrace_common_fields;
 648         struct list_head *head = trace_get_fields(call);
 649
 650         (*pos)++;
 651
 652         switch ((unsigned long)v) {
 653         case FORMAT_HEADER:
 654                 if (unlikely(list_empty(common_head)))
 655                         return NULL;
 656
 657                 field = list_entry(common_head->prev,
 658                                    struct ftrace_event_field, link);
 659                 return field;
 660
 661         case FORMAT_FIELD_SEPERATOR:
 662                 if (unlikely(list_empty(head)))
 663                         return NULL;
 664
 665                 field = list_entry(head->prev, struct ftrace_event_field, link);
 666                 return field;
 667
 668         case FORMAT_PRINTFMT:
 669                 /* all done */
 670                 return NULL;
 671         }
 672
 673         field = v;
 674         if (field->link.prev == common_head)
 675                 return (void *)FORMAT_FIELD_SEPERATOR;
 676         else if (field->link.prev == head)
 677                 return (void *)FORMAT_PRINTFMT;
 678
 679         field = list_entry(field->link.prev, struct ftrace_event_field, link);
 680
 681         return field;
 682 }
 683
 684 static void *f_start(struct seq_file *m, loff_t *pos)
 685 {
 686         loff_t l = 0;
 687         void *p;
 688
 689         /* Start by showing the header */
 690         if (!*pos)
 691                 return (void *)FORMAT_HEADER;
 692
 693         p = (void *)FORMAT_HEADER;
 694         do {
 695                 p = f_next(m, p, &l);
 696         } while (p && l < *pos);
 697
 698         return p;
 699 }
 700
 701 static int f_show(struct seq_file *m, void *v)
 702 {
 703         struct ftrace_event_call *call = m->private;
 704         struct ftrace_event_field *field;
 705         const char *array_descriptor;
 706
 707         switch ((unsigned long)v) {
 708         case FORMAT_HEADER:
 709                 seq_printf(m, "name: %s\n", call->name);
 710                 seq_printf(m, "ID: %d\n", call->event.type);
 711                 seq_printf(m, "format:\n");
 712                 return 0;
 713
 714         case FORMAT_FIELD_SEPERATOR:
 715                 seq_putc(m, '\n');
 716                 return 0;
 717
 718         case FORMAT_PRINTFMT:
 719                 seq_printf(m, "\nprint fmt: %s\n",
 720                            call->print_fmt);
 721                 return 0;
 722         }
 723
 724         field = v;
 725
 726         /*
 727          * Smartly shows the array type(except dynamic array).
 728          * Normal:
 729          *      field:TYPE VAR
 730          * If TYPE := TYPE[LEN], it is shown:
 731          *      field:TYPE VAR[LEN]
 732          */
 733         array_descriptor = strchr(field->type, '[');
 734
 735         if (!strncmp(field->type, "__data_loc", 10))
 736                 array_descriptor = NULL;
 737
 738         if (!array_descriptor)
 739                 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
 740                            field->type, field->name, field->offset,
 741                            field->size, !!field->is_signed);
 742         else
 743                 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
 744                            (int)(array_descriptor - field->type),
 745                            field->type, field->name,
 746                            array_descriptor, field->offset,
 747                            field->size, !!field->is_signed);
 748
 749         return 0;
 750 }
 751
 752 static void f_stop(struct seq_file *m, void *p)
 753 {
 754 }
 755
 756 static const struct seq_operations trace_format_seq_ops = {
 757         .start          = f_start,
 758         .next           = f_next,
 759         .stop           = f_stop,
 760         .show           = f_show,
 761 };
 762
 763 static int trace_format_open(struct inode *inode, struct file *file)
 764 {
 765         struct ftrace_event_call *call = inode->i_private;
 766         struct seq_file *m;
 767         int ret;
 768
 769         ret = seq_open(file, &trace_format_seq_ops);
 770         if (ret < 0)
 771                 return ret;
 772
 773         m = file->private_data;
 774         m->private = call;
 775
 776         return 0;
 777 }
 778
 779 static ssize_t
 780 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 781 {
 782         struct ftrace_event_call *call = filp->private_data;
 783         struct trace_seq *s;
 784         int r;
 785
 786         if (*ppos)
 787                 return 0;
 788
 789         s = kmalloc(sizeof(*s), GFP_KERNEL);
 790         if (!s)
 791                 return -ENOMEM;
 792
 793         trace_seq_init(s);
 794         trace_seq_printf(s, "%d\n", call->event.type);
 795
 796         r = simple_read_from_buffer(ubuf, cnt, ppos,
 797                                     s->buffer, s->len);
 798         kfree(s);
 799         return r;
 800 }
 801
 802 static ssize_t
 803 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 804                   loff_t *ppos)
 805 {
 806         struct ftrace_event_call *call = filp->private_data;
 807         struct trace_seq *s;
 808         int r;
 809
 810         if (*ppos)
 811                 return 0;
 812
 813         s = kmalloc(sizeof(*s), GFP_KERNEL);
 814         if (!s)
 815                 return -ENOMEM;
 816
 817         trace_seq_init(s);
 818
 819         print_event_filter(call, s);
 820         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 821
 822         kfree(s);
 823
 824         return r;
 825 }
 826
 827 static ssize_t
 828 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 829                    loff_t *ppos)
 830 {
 831         struct ftrace_event_call *call = filp->private_data;
 832         char *buf;
 833         int err;
 834
 835         if (cnt >= PAGE_SIZE)
 836                 return -EINVAL;
 837
 838         buf = (char *)__get_free_page(GFP_TEMPORARY);
 839         if (!buf)
 840                 return -ENOMEM;
 841
 842         if (copy_from_user(buf, ubuf, cnt)) {
 843                 free_page((unsigned long) buf);
 844                 return -EFAULT;
 845         }
 846         buf[cnt] = '\0';
 847
 848         err = apply_event_filter(call, buf);
 849         free_page((unsigned long) buf);
 850         if (err < 0)
 851                 return err;
 852
 853         *ppos += cnt;
 854
 855         return cnt;
 856 }
 857
 858 static LIST_HEAD(event_subsystems);
 859
 860 static int subsystem_open(struct inode *inode, struct file *filp)
 861 {
 862         struct event_subsystem *system = NULL;
 863         int ret;
 864
 865         /* Make sure the system still exists */
 866         mutex_lock(&event_mutex);
 867         list_for_each_entry(system, &event_subsystems, list) {
 868                 if (system == inode->i_private) {
 869                         /* Don't open systems with no events */
 870                         if (!system->nr_events) {
 871                                 system = NULL;
 872                                 break;
 873                         }
 874                         __get_system(system);
 875                         break;
 876                 }
 877         }
 878         mutex_unlock(&event_mutex);
 879
 880         if (system != inode->i_private)
 881                 return -ENODEV;
 882
 883         ret = tracing_open_generic(inode, filp);
 884         if (ret < 0)
 885                 put_system(system);
 886
 887         return ret;
 888 }
 889
 890 static int subsystem_release(struct inode *inode, struct file *file)
 891 {
 892         struct event_subsystem *system = inode->i_private;
 893
 894         put_system(system);
 895
 896         return 0;
 897 }
 898
 899 static ssize_t
 900 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 901                       loff_t *ppos)
 902 {
 903         struct event_subsystem *system = filp->private_data;
 904         struct trace_seq *s;
 905         int r;
 906
 907         if (*ppos)
 908                 return 0;
 909
 910         s = kmalloc(sizeof(*s), GFP_KERNEL);
 911         if (!s)
 912                 return -ENOMEM;
 913
 914         trace_seq_init(s);
 915
 916         print_subsystem_event_filter(system, s);
 917         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 918
 919         kfree(s);
 920
 921         return r;
 922 }
 923
 924 static ssize_t
 925 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 926                        loff_t *ppos)
 927 {
 928         struct event_subsystem *system = filp->private_data;
 929         char *buf;
 930         int err;
 931
 932         if (cnt >= PAGE_SIZE)
 933                 return -EINVAL;
 934
 935         buf = (char *)__get_free_page(GFP_TEMPORARY);
 936         if (!buf)
 937                 return -ENOMEM;
 938
 939         if (copy_from_user(buf, ubuf, cnt)) {
 940                 free_page((unsigned long) buf);
 941                 return -EFAULT;
 942         }
 943         buf[cnt] = '\0';
 944
 945         err = apply_subsystem_event_filter(system, buf);
 946         free_page((unsigned long) buf);
 947         if (err < 0)
 948                 return err;
 949
 950         *ppos += cnt;
 951
 952         return cnt;
 953 }
 954
 955 static ssize_t
 956 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 957 {
 958         int (*func)(struct trace_seq *s) = filp->private_data;
 959         struct trace_seq *s;
 960         int r;
 961
 962         if (*ppos)
 963                 return 0;
 964
 965         s = kmalloc(sizeof(*s), GFP_KERNEL);
 966         if (!s)
 967                 return -ENOMEM;
 968
 969         trace_seq_init(s);
 970
 971         func(s);
 972         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 973
 974         kfree(s);
 975
 976         return r;
 977 }
 978
 979 static const struct seq_operations show_event_seq_ops = {
 980         .start = t_start,
 981         .next = t_next,
 982         .show = t_show,
 983         .stop = t_stop,
 984 };
 985
 986 static const struct seq_operations show_set_event_seq_ops = {
 987         .start = s_start,
 988         .next = s_next,
 989         .show = t_show,
 990         .stop = t_stop,
 991 };
 992
 993 static const struct file_operations ftrace_avail_fops = {
 994         .open = ftrace_event_seq_open,
 995         .read = seq_read,
 996         .llseek = seq_lseek,
 997         .release = seq_release,
 998 };
 999
1000 static const struct file_operations ftrace_set_event_fops = {
1001         .open = ftrace_event_seq_open,
1002         .read = seq_read,
1003         .write = ftrace_event_write,
1004         .llseek = seq_lseek,
1005         .release = seq_release,
1006 };
1007
1008 static const struct file_operations ftrace_enable_fops = {
1009         .open = tracing_open_generic,
1010         .read = event_enable_read,
1011         .write = event_enable_write,
1012         .llseek = default_llseek,
1013 };
1014
1015 static const struct file_operations ftrace_event_format_fops = {
1016         .open = trace_format_open,
1017         .read = seq_read,
1018         .llseek = seq_lseek,
1019         .release = seq_release,
1020 };
1021
1022 static const struct file_operations ftrace_event_id_fops = {
1023         .open = tracing_open_generic,
1024         .read = event_id_read,
1025         .llseek = default_llseek,
1026 };
1027
1028 static const struct file_operations ftrace_event_filter_fops = {
1029         .open = tracing_open_generic,
1030         .read = event_filter_read,
1031         .write = event_filter_write,
1032         .llseek = default_llseek,
1033 };
1034
1035 static const struct file_operations ftrace_subsystem_filter_fops = {
1036         .open = subsystem_open,
1037         .read = subsystem_filter_read,
1038         .write = subsystem_filter_write,
1039         .llseek = default_llseek,
1040         .release = subsystem_release,
1041 };
1042
1043 static const struct file_operations ftrace_system_enable_fops = {
1044         .open = tracing_open_generic,
1045         .read = system_enable_read,
1046         .write = system_enable_write,
1047         .llseek = default_llseek,
1048 };
1049
1050 static const struct file_operations ftrace_show_header_fops = {
1051         .open = tracing_open_generic,
1052         .read = show_header,
1053         .llseek = default_llseek,
1054 };
1055
1056 static struct dentry *event_trace_events_dir(void)
1057 {
1058         static struct dentry *d_tracer;
1059         static struct dentry *d_events;
1060
1061         if (d_events)
1062                 return d_events;
1063
1064         d_tracer = tracing_init_dentry();
1065         if (!d_tracer)
1066                 return NULL;
1067
1068         d_events = debugfs_create_dir("events", d_tracer);
1069         if (!d_events)
1070                 pr_warning("Could not create debugfs "
1071                            "'events' directory\n");
1072
1073         return d_events;
1074 }
1075
1076 static struct dentry *
1077 event_subsystem_dir(const char *name, struct dentry *d_events)
1078 {
1079         struct event_subsystem *system;
1080         struct dentry *entry;
1081
1082         /* First see if we did not already create this dir */
1083         list_for_each_entry(system, &event_subsystems, list) {
1084                 if (strcmp(system->name, name) == 0) {
1085                         __get_system(system);
1086                         system->nr_events++;
1087                         return system->entry;
1088                 }
1089         }
1090
1091         /* need to create new entry */
1092         system = kmalloc(sizeof(*system), GFP_KERNEL);
1093         if (!system) {
1094                 pr_warning("No memory to create event subsystem %s\n",
1095                            name);
1096                 return d_events;
1097         }
1098
1099         system->entry = debugfs_create_dir(name, d_events);
1100         if (!system->entry) {
1101                 pr_warning("Could not create event subsystem %s\n",
1102                            name);
1103                 kfree(system);
1104                 return d_events;
1105         }
1106
1107         system->nr_events = 1;
1108         system->ref_count = 1;
1109         system->name = kstrdup(name, GFP_KERNEL);
1110         if (!system->name) {
1111                 debugfs_remove(system->entry);
1112                 kfree(system);
1113                 return d_events;
1114         }
1115
1116         list_add(&system->list, &event_subsystems);
1117
1118         system->filter = NULL;
1119
1120         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1121         if (!system->filter) {
1122                 pr_warning("Could not allocate filter for subsystem "
1123                            "'%s'\n", name);
1124                 return system->entry;
1125         }
1126
1127         entry = debugfs_create_file("filter", 0644, system->entry, system,
1128                                     &ftrace_subsystem_filter_fops);
1129         if (!entry) {
1130                 kfree(system->filter);
1131                 system->filter = NULL;
1132                 pr_warning("Could not create debugfs "
1133                            "'%s/filter' entry\n", name);
1134         }
1135
1136         trace_create_file("enable", 0644, system->entry,
1137                           (void *)system->name,
1138                           &ftrace_system_enable_fops);
1139
1140         return system->entry;
1141 }
1142
1143 static int
1144 event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
1145                  const struct file_operations *id,
1146                  const struct file_operations *enable,
1147                  const struct file_operations *filter,
1148                  const struct file_operations *format)
1149 {
1150         struct list_head *head;
1151         int ret;
1152
1153         /*
1154          * If the trace point header did not define TRACE_SYSTEM
1155          * then the system would be called "TRACE_SYSTEM".
1156          */
1157         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1158                 d_events = event_subsystem_dir(call->class->system, d_events);
1159
1160         call->dir = debugfs_create_dir(call->name, d_events);
1161         if (!call->dir) {
1162                 pr_warning("Could not create debugfs "
1163                            "'%s' directory\n", call->name);
1164                 return -1;
1165         }
1166
1167         if (call->class->reg)
1168                 trace_create_file("enable", 0644, call->dir, call,
1169                                   enable);
1170
1171 #ifdef CONFIG_PERF_EVENTS
1172         if (call->event.type && call->class->reg)
1173                 trace_create_file("id", 0444, call->dir, call,
1174                                   id);
1175 #endif
1176
1177         /*
1178          * Other events may have the same class. Only update
1179          * the fields if they are not already defined.
1180          */
1181         head = trace_get_fields(call);
1182         if (list_empty(head)) {
1183                 ret = call->class->define_fields(call);
1184                 if (ret < 0) {
1185                         pr_warning("Could not initialize trace point"
1186                                    " events/%s\n", call->name);
1187                         return ret;
1188                 }
1189         }
1190         trace_create_file("filter", 0644, call->dir, call,
1191                           filter);
1192
1193         trace_create_file("format", 0444, call->dir, call,
1194                           format);
1195
1196         return 0;
1197 }
1198
1199 static int
1200 __trace_add_event_call(struct ftrace_event_call *call, struct module *mod,
1201                        const struct file_operations *id,
1202                        const struct file_operations *enable,
1203                        const struct file_operations *filter,
1204                        const struct file_operations *format)
1205 {
1206         struct dentry *d_events;
1207         int ret;
1208
1209         /* The linker may leave blanks */
1210         if (!call->name)
1211                 return -EINVAL;
1212
1213         if (call->class->raw_init) {
1214                 ret = call->class->raw_init(call);
1215                 if (ret < 0) {
1216                         if (ret != -ENOSYS)
1217                                 pr_warning("Could not initialize trace events/%s\n",
1218                                            call->name);
1219                         return ret;
1220                 }
1221         }
1222
1223         d_events = event_trace_events_dir();
1224         if (!d_events)
1225                 return -ENOENT;
1226
1227         ret = event_create_dir(call, d_events, id, enable, filter, format);
1228         if (!ret)
1229                 list_add(&call->list, &ftrace_events);
1230         call->mod = mod;
1231
1232         return ret;
1233 }
1234
1235 /* Add an additional event_call dynamically */
1236 int trace_add_event_call(struct ftrace_event_call *call)
1237 {
1238         int ret;
1239         mutex_lock(&event_mutex);
1240         ret = __trace_add_event_call(call, NULL, &ftrace_event_id_fops,
1241                                      &ftrace_enable_fops,
1242                                      &ftrace_event_filter_fops,
1243                                      &ftrace_event_format_fops);
1244         mutex_unlock(&event_mutex);
1245         return ret;
1246 }
1247
1248 static void remove_subsystem_dir(const char *name)
1249 {
1250         struct event_subsystem *system;
1251
1252         if (strcmp(name, TRACE_SYSTEM) == 0)
1253                 return;
1254
1255         list_for_each_entry(system, &event_subsystems, list) {
1256                 if (strcmp(system->name, name) == 0) {
1257                         if (!--system->nr_events) {
1258                                 debugfs_remove_recursive(system->entry);
1259                                 list_del(&system->list);
1260                                 __put_system(system);
1261                         }
1262                         break;
1263                 }
1264         }
1265 }
1266
1267 /*
1268  * Must be called under locking both of event_mutex and trace_event_mutex.
1269  */
1270 static void __trace_remove_event_call(struct ftrace_event_call *call)
1271 {
1272         ftrace_event_enable_disable(call, 0);
1273         if (call->event.funcs)
1274                 __unregister_ftrace_event(&call->event);
1275         debugfs_remove_recursive(call->dir);
1276         list_del(&call->list);
1277         trace_destroy_fields(call);
1278         destroy_preds(call);
1279         remove_subsystem_dir(call->class->system);
1280 }
1281
1282 /* Remove an event_call */
1283 void trace_remove_event_call(struct ftrace_event_call *call)
1284 {
1285         mutex_lock(&event_mutex);
1286         down_write(&trace_event_mutex);
1287         __trace_remove_event_call(call);
1288         up_write(&trace_event_mutex);
1289         mutex_unlock(&event_mutex);
1290 }
1291
1292 #define for_each_event(event, start, end)                       \
1293         for (event = start;                                     \
1294              (unsigned long)event < (unsigned long)end;         \
1295              event++)
1296
1297 #ifdef CONFIG_MODULES
1298
1299 static LIST_HEAD(ftrace_module_file_list);
1300
1301 /*
1302  * Modules must own their file_operations to keep up with
1303  * reference counting.
1304  */
1305 struct ftrace_module_file_ops {
1306         struct list_head                list;
1307         struct module                   *mod;
1308         struct file_operations          id;
1309         struct file_operations          enable;
1310         struct file_operations          format;
1311         struct file_operations          filter;
1312 };
1313
1314 static struct ftrace_module_file_ops *
1315 trace_create_file_ops(struct module *mod)
1316 {
1317         struct ftrace_module_file_ops *file_ops;
1318
1319         /*
1320          * This is a bit of a PITA. To allow for correct reference
1321          * counting, modules must "own" their file_operations.
1322          * To do this, we allocate the file operations that will be
1323          * used in the event directory.
1324          */
1325
1326         file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1327         if (!file_ops)
1328                 return NULL;
1329
1330         file_ops->mod = mod;
1331
1332         file_ops->id = ftrace_event_id_fops;
1333         file_ops->id.owner = mod;
1334
1335         file_ops->enable = ftrace_enable_fops;
1336         file_ops->enable.owner = mod;
1337
1338         file_ops->filter = ftrace_event_filter_fops;
1339         file_ops->filter.owner = mod;
1340
1341         file_ops->format = ftrace_event_format_fops;
1342         file_ops->format.owner = mod;
1343
1344         list_add(&file_ops->list, &ftrace_module_file_list);
1345
1346         return file_ops;
1347 }
1348
1349 static void trace_module_add_events(struct module *mod)
1350 {
1351         struct ftrace_module_file_ops *file_ops = NULL;
1352         struct ftrace_event_call **call, **start, **end;
1353
1354         start = mod->trace_events;
1355         end = mod->trace_events + mod->num_trace_events;
1356
1357         if (start == end)
1358                 return;
1359
1360         file_ops = trace_create_file_ops(mod);
1361         if (!file_ops)
1362                 return;
1363
1364         for_each_event(call, start, end) {
1365                 __trace_add_event_call(*call, mod,
1366                                        &file_ops->id, &file_ops->enable,
1367                                        &file_ops->filter, &file_ops->format);
1368         }
1369 }
1370
1371 static void trace_module_remove_events(struct module *mod)
1372 {
1373         struct ftrace_module_file_ops *file_ops;
1374         struct ftrace_event_call *call, *p;
1375         bool found = false;
1376
1377         down_write(&trace_event_mutex);
1378         list_for_each_entry_safe(call, p, &ftrace_events, list) {
1379                 if (call->mod == mod) {
1380                         found = true;
1381                         __trace_remove_event_call(call);
1382                 }
1383         }
1384
1385         /* Now free the file_operations */
1386         list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1387                 if (file_ops->mod == mod)
1388                         break;
1389         }
1390         if (&file_ops->list != &ftrace_module_file_list) {
1391                 list_del(&file_ops->list);
1392                 kfree(file_ops);
1393         }
1394
1395         /*
1396          * It is safest to reset the ring buffer if the module being unloaded
1397          * registered any events.
1398          */
1399         if (found)
1400                 tracing_reset_current_online_cpus();
1401         up_write(&trace_event_mutex);
1402 }
1403
1404 static int trace_module_notify(struct notifier_block *self,
1405                                unsigned long val, void *data)
1406 {
1407         struct module *mod = data;
1408
1409         mutex_lock(&event_mutex);
1410         switch (val) {
1411         case MODULE_STATE_COMING:
1412                 trace_module_add_events(mod);
1413                 break;
1414         case MODULE_STATE_GOING:
1415                 trace_module_remove_events(mod);
1416                 break;
1417         }
1418         mutex_unlock(&event_mutex);
1419
1420         return 0;
1421 }
1422 #else
1423 static int trace_module_notify(struct notifier_block *self,
1424                                unsigned long val, void *data)
1425 {
1426         return 0;
1427 }
1428 #endif /* CONFIG_MODULES */
1429
1430 static struct notifier_block trace_module_nb = {
1431         .notifier_call = trace_module_notify,
1432         .priority = 0,
1433 };
1434
1435 extern struct ftrace_event_call *__start_ftrace_events[];
1436 extern struct ftrace_event_call *__stop_ftrace_events[];
1437
1438 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
1439
1440 static __init int setup_trace_event(char *str)
1441 {
1442         strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
1443         ring_buffer_expanded = 1;
1444         tracing_selftest_disabled = 1;
1445
1446         return 1;
1447 }
1448 __setup("trace_event=", setup_trace_event);
1449
1450 static __init int event_trace_init(void)
1451 {
1452         struct ftrace_event_call **call;
1453         struct dentry *d_tracer;
1454         struct dentry *entry;
1455         struct dentry *d_events;
1456         int ret;
1457         char *buf = bootup_event_buf;
1458         char *token;
1459
1460         d_tracer = tracing_init_dentry();
1461         if (!d_tracer)
1462                 return 0;
1463
1464         entry = debugfs_create_file("available_events", 0444, d_tracer,
1465                                     (void *)&show_event_seq_ops,
1466                                     &ftrace_avail_fops);
1467         if (!entry)
1468                 pr_warning("Could not create debugfs "
1469                            "'available_events' entry\n");
1470
1471         entry = debugfs_create_file("set_event", 0644, d_tracer,
1472                                     (void *)&show_set_event_seq_ops,
1473                                     &ftrace_set_event_fops);
1474         if (!entry)
1475                 pr_warning("Could not create debugfs "
1476                            "'set_event' entry\n");
1477
1478         d_events = event_trace_events_dir();
1479         if (!d_events)
1480                 return 0;
1481
1482         /* ring buffer internal formats */
1483         trace_create_file("header_page", 0444, d_events,
1484                           ring_buffer_print_page_header,
1485                           &ftrace_show_header_fops);
1486
1487         trace_create_file("header_event", 0444, d_events,
1488                           ring_buffer_print_entry_header,
1489                           &ftrace_show_header_fops);
1490
1491         trace_create_file("enable", 0644, d_events,
1492                           NULL, &ftrace_system_enable_fops);
1493
1494         if (trace_define_common_fields())
1495                 pr_warning("tracing: Failed to allocate common fields");
1496
1497         for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
1498                 __trace_add_event_call(*call, NULL, &ftrace_event_id_fops,
1499                                        &ftrace_enable_fops,
1500                                        &ftrace_event_filter_fops,
1501                                        &ftrace_event_format_fops);
1502         }
1503
1504         while (true) {
1505                 token = strsep(&buf, ",");
1506
1507                 if (!token)
1508                         break;
1509                 if (!*token)
1510                         continue;
1511
1512                 ret = ftrace_set_clr_event(token, 1);
1513                 if (ret)
1514                         pr_warning("Failed to enable trace event: %s\n", token);
1515         }
1516
1517         ret = register_module_notifier(&trace_module_nb);
1518         if (ret)
1519                 pr_warning("Failed to register trace events module notifier\n");
1520
1521         return 0;
1522 }
1523 fs_initcall(event_trace_init);
1524
1525 #ifdef CONFIG_FTRACE_STARTUP_TEST
1526
1527 static DEFINE_SPINLOCK(test_spinlock);
1528 static DEFINE_SPINLOCK(test_spinlock_irq);
1529 static DEFINE_MUTEX(test_mutex);
1530
1531 static __init void test_work(struct work_struct *dummy)
1532 {
1533         spin_lock(&test_spinlock);
1534         spin_lock_irq(&test_spinlock_irq);
1535         udelay(1);
1536         spin_unlock_irq(&test_spinlock_irq);
1537         spin_unlock(&test_spinlock);
1538
1539         mutex_lock(&test_mutex);
1540         msleep(1);
1541         mutex_unlock(&test_mutex);
1542 }
1543
1544 static __init int event_test_thread(void *unused)
1545 {
1546         void *test_malloc;
1547
1548         test_malloc = kmalloc(1234, GFP_KERNEL);
1549         if (!test_malloc)
1550                 pr_info("failed to kmalloc\n");
1551
1552         schedule_on_each_cpu(test_work);
1553
1554         kfree(test_malloc);
1555
1556         set_current_state(TASK_INTERRUPTIBLE);
1557         while (!kthread_should_stop())
1558                 schedule();
1559
1560         return 0;
1561 }
1562
1563 /*
1564  * Do various things that may trigger events.
1565  */
1566 static __init void event_test_stuff(void)
1567 {
1568         struct task_struct *test_thread;
1569
1570         test_thread = kthread_run(event_test_thread, NULL, "test-events");
1571         msleep(1);
1572         kthread_stop(test_thread);
1573 }
1574
1575 /*
1576  * For every trace event defined, we will test each trace point separately,
1577  * and then by groups, and finally all trace points.
1578  */
1579 static __init void event_trace_self_tests(void)
1580 {
1581         struct ftrace_event_call *call;
1582         struct event_subsystem *system;
1583         int ret;
1584
1585         pr_info("Running tests on trace events:\n");
1586
1587         list_for_each_entry(call, &ftrace_events, list) {
1588
1589                 /* Only test those that have a probe */
1590                 if (!call->class || !call->class->probe)
1591                         continue;
1592
1593 /*
1594  * Testing syscall events here is pretty useless, but
1595  * we still do it if configured. But this is time consuming.
1596  * What we really need is a user thread to perform the
1597  * syscalls as we test.
1598  */
1599 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
1600                 if (call->class->system &&
1601                     strcmp(call->class->system, "syscalls") == 0)
1602                         continue;
1603 #endif
1604
1605                 pr_info("Testing event %s: ", call->name);
1606
1607                 /*
1608                  * If an event is already enabled, someone is using
1609                  * it and the self test should not be on.
1610                  */
1611                 if (call->flags & TRACE_EVENT_FL_ENABLED) {
1612                         pr_warning("Enabled event during self test!\n");
1613                         WARN_ON_ONCE(1);
1614                         continue;
1615                 }
1616
1617                 ftrace_event_enable_disable(call, 1);
1618                 event_test_stuff();
1619                 ftrace_event_enable_disable(call, 0);
1620
1621                 pr_cont("OK\n");
1622         }
1623
1624         /* Now test at the sub system level */
1625
1626         pr_info("Running tests on trace event systems:\n");
1627
1628         list_for_each_entry(system, &event_subsystems, list) {
1629
1630                 /* the ftrace system is special, skip it */
1631                 if (strcmp(system->name, "ftrace") == 0)
1632                         continue;
1633
1634                 pr_info("Testing event system %s: ", system->name);
1635
1636                 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
1637                 if (WARN_ON_ONCE(ret)) {
1638                         pr_warning("error enabling system %s\n",
1639                                    system->name);
1640                         continue;
1641                 }
1642
1643                 event_test_stuff();
1644
1645                 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
1646                 if (WARN_ON_ONCE(ret))
1647                         pr_warning("error disabling system %s\n",
1648                                    system->name);
1649
1650                 pr_cont("OK\n");
1651         }
1652
1653         /* Test with all events enabled */
1654
1655         pr_info("Running tests on all trace events:\n");
1656         pr_info("Testing all events: ");
1657
1658         ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
1659         if (WARN_ON_ONCE(ret)) {
1660                 pr_warning("error enabling all events\n");
1661                 return;
1662         }
1663
1664         event_test_stuff();
1665
1666         /* reset sysname */
1667         ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
1668         if (WARN_ON_ONCE(ret)) {
1669                 pr_warning("error disabling all events\n");
1670                 return;
1671         }
1672
1673         pr_cont("OK\n");
1674 }
1675
1676 #ifdef CONFIG_FUNCTION_TRACER
1677
1678 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
1679
1680 static void
1681 function_test_events_call(unsigned long ip, unsigned long parent_ip)
1682 {
1683         struct ring_buffer_event *event;
1684         struct ring_buffer *buffer;
1685         struct ftrace_entry *entry;
1686         unsigned long flags;
1687         long disabled;
1688         int cpu;
1689         int pc;
1690
1691         pc = preempt_count();
1692         preempt_disable_notrace();
1693         cpu = raw_smp_processor_id();
1694         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
1695
1696         if (disabled != 1)
1697                 goto out;
1698
1699         local_save_flags(flags);
1700
1701         event = trace_current_buffer_lock_reserve(&buffer,
1702                                                   TRACE_FN, sizeof(*entry),
1703                                                   flags, pc);
1704         if (!event)
1705                 goto out;
1706         entry   = ring_buffer_event_data(event);
1707         entry->ip                       = ip;
1708         entry->parent_ip                = parent_ip;
1709
1710         trace_nowake_buffer_unlock_commit(buffer, event, flags, pc);
1711
1712  out:
1713         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
1714         preempt_enable_notrace();
1715 }
1716
1717 static struct ftrace_ops trace_ops __initdata  =
1718 {
1719         .func = function_test_events_call,
1720 };
1721
1722 static __init void event_trace_self_test_with_function(void)
1723 {
1724         int ret;
1725         ret = register_ftrace_function(&trace_ops);
1726         if (WARN_ON(ret < 0)) {
1727                 pr_info("Failed to enable function tracer for event tests\n");
1728                 return;
1729         }
1730         pr_info("Running tests again, along with the function tracer\n");
1731         event_trace_self_tests();
1732         unregister_ftrace_function(&trace_ops);
1733 }
1734 #else
1735 static __init void event_trace_self_test_with_function(void)
1736 {
1737 }
1738 #endif
1739
1740 static __init int event_trace_self_tests_init(void)
1741 {
1742         if (!tracing_selftest_disabled) {
1743                 event_trace_self_tests();
1744                 event_trace_self_test_with_function();
1745         }
1746
1747         return 0;
1748 }
1749
1750 late_initcall(event_trace_self_tests_init);
1751
1752 #endif