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/delay.h>
  19
  20 #include "trace_output.h"
  21
  22 #define TRACE_SYSTEM "TRACE_SYSTEM"
  23
  24 static DEFINE_MUTEX(event_mutex);
  25
  26 LIST_HEAD(ftrace_events);
  27
  28 int trace_define_field(struct ftrace_event_call *call, char *type,
  29                        char *name, int offset, int size, int is_signed)
  30 {
  31         struct ftrace_event_field *field;
  32
  33         field = kzalloc(sizeof(*field), GFP_KERNEL);
  34         if (!field)
  35                 goto err;
  36
  37         field->name = kstrdup(name, GFP_KERNEL);
  38         if (!field->name)
  39                 goto err;
  40
  41         field->type = kstrdup(type, GFP_KERNEL);
  42         if (!field->type)
  43                 goto err;
  44
  45         field->offset = offset;
  46         field->size = size;
  47         field->is_signed = is_signed;
  48         list_add(&field->link, &call->fields);
  49
  50         return 0;
  51
  52 err:
  53         if (field) {
  54                 kfree(field->name);
  55                 kfree(field->type);
  56         }
  57         kfree(field);
  58
  59         return -ENOMEM;
  60 }
  61 EXPORT_SYMBOL_GPL(trace_define_field);
  62
  63 #ifdef CONFIG_MODULES
  64
  65 static void trace_destroy_fields(struct ftrace_event_call *call)
  66 {
  67         struct ftrace_event_field *field, *next;
  68
  69         list_for_each_entry_safe(field, next, &call->fields, link) {
  70                 list_del(&field->link);
  71                 kfree(field->type);
  72                 kfree(field->name);
  73                 kfree(field);
  74         }
  75 }
  76
  77 #endif /* CONFIG_MODULES */
  78
  79 static void ftrace_clear_events(void)
  80 {
  81         struct ftrace_event_call *call;
  82
  83         list_for_each_entry(call, &ftrace_events, list) {
  84
  85                 if (call->enabled) {
  86                         call->enabled = 0;
  87                         call->unregfunc();
  88                 }
  89         }
  90 }
  91
  92 static void ftrace_event_enable_disable(struct ftrace_event_call *call,
  93                                         int enable)
  94 {
  95
  96         switch (enable) {
  97         case 0:
  98                 if (call->enabled) {
  99                         call->enabled = 0;
 100                         call->unregfunc();
 101                 }
 102                 break;
 103         case 1:
 104                 if (!call->enabled) {
 105                         call->enabled = 1;
 106                         call->regfunc();
 107                 }
 108                 break;
 109         }
 110 }
 111
 112 static int ftrace_set_clr_event(char *buf, int set)
 113 {
 114         struct ftrace_event_call *call;
 115         char *event = NULL, *sub = NULL, *match;
 116         int ret = -EINVAL;
 117
 118         /*
 119          * The buf format can be <subsystem>:<event-name>
 120          *  *:<event-name> means any event by that name.
 121          *  :<event-name> is the same.
 122          *
 123          *  <subsystem>:* means all events in that subsystem
 124          *  <subsystem>: means the same.
 125          *
 126          *  <name> (no ':') means all events in a subsystem with
 127          *  the name <name> or any event that matches <name>
 128          */
 129
 130         match = strsep(&buf, ":");
 131         if (buf) {
 132                 sub = match;
 133                 event = buf;
 134                 match = NULL;
 135
 136                 if (!strlen(sub) || strcmp(sub, "*") == 0)
 137                         sub = NULL;
 138                 if (!strlen(event) || strcmp(event, "*") == 0)
 139                         event = NULL;
 140         }
 141
 142         mutex_lock(&event_mutex);
 143         list_for_each_entry(call, &ftrace_events, list) {
 144
 145                 if (!call->name || !call->regfunc)
 146                         continue;
 147
 148                 if (match &&
 149                     strcmp(match, call->name) != 0 &&
 150                     strcmp(match, call->system) != 0)
 151                         continue;
 152
 153                 if (sub && strcmp(sub, call->system) != 0)
 154                         continue;
 155
 156                 if (event && strcmp(event, call->name) != 0)
 157                         continue;
 158
 159                 ftrace_event_enable_disable(call, set);
 160
 161                 ret = 0;
 162         }
 163         mutex_unlock(&event_mutex);
 164
 165         return ret;
 166 }
 167
 168 /* 128 should be much more than enough */
 169 #define EVENT_BUF_SIZE          127
 170
 171 static ssize_t
 172 ftrace_event_write(struct file *file, const char __user *ubuf,
 173                    size_t cnt, loff_t *ppos)
 174 {
 175         size_t read = 0;
 176         int i, set = 1;
 177         ssize_t ret;
 178         char *buf;
 179         char ch;
 180
 181         if (!cnt || cnt < 0)
 182                 return 0;
 183
 184         ret = tracing_update_buffers();
 185         if (ret < 0)
 186                 return ret;
 187
 188         ret = get_user(ch, ubuf++);
 189         if (ret)
 190                 return ret;
 191         read++;
 192         cnt--;
 193
 194         /* skip white space */
 195         while (cnt && isspace(ch)) {
 196                 ret = get_user(ch, ubuf++);
 197                 if (ret)
 198                         return ret;
 199                 read++;
 200                 cnt--;
 201         }
 202
 203         /* Only white space found? */
 204         if (isspace(ch)) {
 205                 file->f_pos += read;
 206                 ret = read;
 207                 return ret;
 208         }
 209
 210         buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
 211         if (!buf)
 212                 return -ENOMEM;
 213
 214         if (cnt > EVENT_BUF_SIZE)
 215                 cnt = EVENT_BUF_SIZE;
 216
 217         i = 0;
 218         while (cnt && !isspace(ch)) {
 219                 if (!i && ch == '!')
 220                         set = 0;
 221                 else
 222                         buf[i++] = ch;
 223
 224                 ret = get_user(ch, ubuf++);
 225                 if (ret)
 226                         goto out_free;
 227                 read++;
 228                 cnt--;
 229         }
 230         buf[i] = 0;
 231
 232         file->f_pos += read;
 233
 234         ret = ftrace_set_clr_event(buf, set);
 235         if (ret)
 236                 goto out_free;
 237
 238         ret = read;
 239
 240  out_free:
 241         kfree(buf);
 242
 243         return ret;
 244 }
 245
 246 static void *
 247 t_next(struct seq_file *m, void *v, loff_t *pos)
 248 {
 249         struct list_head *list = m->private;
 250         struct ftrace_event_call *call;
 251
 252         (*pos)++;
 253
 254         for (;;) {
 255                 if (list == &ftrace_events)
 256                         return NULL;
 257
 258                 call = list_entry(list, struct ftrace_event_call, list);
 259
 260                 /*
 261                  * The ftrace subsystem is for showing formats only.
 262                  * They can not be enabled or disabled via the event files.
 263                  */
 264                 if (call->regfunc)
 265                         break;
 266
 267                 list = list->next;
 268         }
 269
 270         m->private = list->next;
 271
 272         return call;
 273 }
 274
 275 static void *t_start(struct seq_file *m, loff_t *pos)
 276 {
 277         return t_next(m, NULL, pos);
 278 }
 279
 280 static void *
 281 s_next(struct seq_file *m, void *v, loff_t *pos)
 282 {
 283         struct list_head *list = m->private;
 284         struct ftrace_event_call *call;
 285
 286         (*pos)++;
 287
 288  retry:
 289         if (list == &ftrace_events)
 290                 return NULL;
 291
 292         call = list_entry(list, struct ftrace_event_call, list);
 293
 294         if (!call->enabled) {
 295                 list = list->next;
 296                 goto retry;
 297         }
 298
 299         m->private = list->next;
 300
 301         return call;
 302 }
 303
 304 static void *s_start(struct seq_file *m, loff_t *pos)
 305 {
 306         return s_next(m, NULL, pos);
 307 }
 308
 309 static int t_show(struct seq_file *m, void *v)
 310 {
 311         struct ftrace_event_call *call = v;
 312
 313         if (strcmp(call->system, TRACE_SYSTEM) != 0)
 314                 seq_printf(m, "%s:", call->system);
 315         seq_printf(m, "%s\n", call->name);
 316
 317         return 0;
 318 }
 319
 320 static void t_stop(struct seq_file *m, void *p)
 321 {
 322 }
 323
 324 static int
 325 ftrace_event_seq_open(struct inode *inode, struct file *file)
 326 {
 327         int ret;
 328         const struct seq_operations *seq_ops;
 329
 330         if ((file->f_mode & FMODE_WRITE) &&
 331             !(file->f_flags & O_APPEND))
 332                 ftrace_clear_events();
 333
 334         seq_ops = inode->i_private;
 335         ret = seq_open(file, seq_ops);
 336         if (!ret) {
 337                 struct seq_file *m = file->private_data;
 338
 339                 m->private = ftrace_events.next;
 340         }
 341         return ret;
 342 }
 343
 344 static ssize_t
 345 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
 346                   loff_t *ppos)
 347 {
 348         struct ftrace_event_call *call = filp->private_data;
 349         char *buf;
 350
 351         if (call->enabled)
 352                 buf = "1\n";
 353         else
 354                 buf = "0\n";
 355
 356         return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
 357 }
 358
 359 static ssize_t
 360 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 361                    loff_t *ppos)
 362 {
 363         struct ftrace_event_call *call = filp->private_data;
 364         char buf[64];
 365         unsigned long val;
 366         int ret;
 367
 368         if (cnt >= sizeof(buf))
 369                 return -EINVAL;
 370
 371         if (copy_from_user(&buf, ubuf, cnt))
 372                 return -EFAULT;
 373
 374         buf[cnt] = 0;
 375
 376         ret = strict_strtoul(buf, 10, &val);
 377         if (ret < 0)
 378                 return ret;
 379
 380         ret = tracing_update_buffers();
 381         if (ret < 0)
 382                 return ret;
 383
 384         switch (val) {
 385         case 0:
 386         case 1:
 387                 mutex_lock(&event_mutex);
 388                 ftrace_event_enable_disable(call, val);
 389                 mutex_unlock(&event_mutex);
 390                 break;
 391
 392         default:
 393                 return -EINVAL;
 394         }
 395
 396         *ppos += cnt;
 397
 398         return cnt;
 399 }
 400
 401 extern char *__bad_type_size(void);
 402
 403 #undef FIELD
 404 #define FIELD(type, name)                                               \
 405         sizeof(type) != sizeof(field.name) ? __bad_type_size() :        \
 406         #type, "common_" #name, offsetof(typeof(field), name),          \
 407                 sizeof(field.name)
 408
 409 static int trace_write_header(struct trace_seq *s)
 410 {
 411         struct trace_entry field;
 412
 413         /* struct trace_entry */
 414         return trace_seq_printf(s,
 415                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
 416                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
 417                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
 418                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
 419                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
 420                                 "\n",
 421                                 FIELD(unsigned short, type),
 422                                 FIELD(unsigned char, flags),
 423                                 FIELD(unsigned char, preempt_count),
 424                                 FIELD(int, pid),
 425                                 FIELD(int, tgid));
 426 }
 427
 428 static ssize_t
 429 event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
 430                   loff_t *ppos)
 431 {
 432         struct ftrace_event_call *call = filp->private_data;
 433         struct trace_seq *s;
 434         char *buf;
 435         int r;
 436
 437         if (*ppos)
 438                 return 0;
 439
 440         s = kmalloc(sizeof(*s), GFP_KERNEL);
 441         if (!s)
 442                 return -ENOMEM;
 443
 444         trace_seq_init(s);
 445
 446         /* If any of the first writes fail, so will the show_format. */
 447
 448         trace_seq_printf(s, "name: %s\n", call->name);
 449         trace_seq_printf(s, "ID: %d\n", call->id);
 450         trace_seq_printf(s, "format:\n");
 451         trace_write_header(s);
 452
 453         r = call->show_format(s);
 454         if (!r) {
 455                 /*
 456                  * ug!  The format output is bigger than a PAGE!!
 457                  */
 458                 buf = "FORMAT TOO BIG\n";
 459                 r = simple_read_from_buffer(ubuf, cnt, ppos,
 460                                               buf, strlen(buf));
 461                 goto out;
 462         }
 463
 464         r = simple_read_from_buffer(ubuf, cnt, ppos,
 465                                     s->buffer, s->len);
 466  out:
 467         kfree(s);
 468         return r;
 469 }
 470
 471 static ssize_t
 472 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 473 {
 474         struct ftrace_event_call *call = filp->private_data;
 475         struct trace_seq *s;
 476         int r;
 477
 478         if (*ppos)
 479                 return 0;
 480
 481         s = kmalloc(sizeof(*s), GFP_KERNEL);
 482         if (!s)
 483                 return -ENOMEM;
 484
 485         trace_seq_init(s);
 486         trace_seq_printf(s, "%d\n", call->id);
 487
 488         r = simple_read_from_buffer(ubuf, cnt, ppos,
 489                                     s->buffer, s->len);
 490         kfree(s);
 491         return r;
 492 }
 493
 494 static ssize_t
 495 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 496                   loff_t *ppos)
 497 {
 498         struct ftrace_event_call *call = filp->private_data;
 499         struct trace_seq *s;
 500         int r;
 501
 502         if (*ppos)
 503                 return 0;
 504
 505         s = kmalloc(sizeof(*s), GFP_KERNEL);
 506         if (!s)
 507                 return -ENOMEM;
 508
 509         trace_seq_init(s);
 510
 511         print_event_filter(call, s);
 512         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 513
 514         kfree(s);
 515
 516         return r;
 517 }
 518
 519 static ssize_t
 520 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 521                    loff_t *ppos)
 522 {
 523         struct ftrace_event_call *call = filp->private_data;
 524         char *buf;
 525         int err;
 526
 527         if (cnt >= PAGE_SIZE)
 528                 return -EINVAL;
 529
 530         buf = (char *)__get_free_page(GFP_TEMPORARY);
 531         if (!buf)
 532                 return -ENOMEM;
 533
 534         if (copy_from_user(buf, ubuf, cnt)) {
 535                 free_page((unsigned long) buf);
 536                 return -EFAULT;
 537         }
 538         buf[cnt] = '\0';
 539
 540         err = apply_event_filter(call, buf);
 541         free_page((unsigned long) buf);
 542         if (err < 0)
 543                 return err;
 544
 545         *ppos += cnt;
 546
 547         return cnt;
 548 }
 549
 550 static ssize_t
 551 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 552                       loff_t *ppos)
 553 {
 554         struct event_subsystem *system = filp->private_data;
 555         struct trace_seq *s;
 556         int r;
 557
 558         if (*ppos)
 559                 return 0;
 560
 561         s = kmalloc(sizeof(*s), GFP_KERNEL);
 562         if (!s)
 563                 return -ENOMEM;
 564
 565         trace_seq_init(s);
 566
 567         print_subsystem_event_filter(system, s);
 568         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 569
 570         kfree(s);
 571
 572         return r;
 573 }
 574
 575 static ssize_t
 576 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 577                        loff_t *ppos)
 578 {
 579         struct event_subsystem *system = filp->private_data;
 580         char *buf;
 581         int err;
 582
 583         if (cnt >= PAGE_SIZE)
 584                 return -EINVAL;
 585
 586         buf = (char *)__get_free_page(GFP_TEMPORARY);
 587         if (!buf)
 588                 return -ENOMEM;
 589
 590         if (copy_from_user(buf, ubuf, cnt)) {
 591                 free_page((unsigned long) buf);
 592                 return -EFAULT;
 593         }
 594         buf[cnt] = '\0';
 595
 596         err = apply_subsystem_event_filter(system, buf);
 597         free_page((unsigned long) buf);
 598         if (err < 0)
 599                 return err;
 600
 601         *ppos += cnt;
 602
 603         return cnt;
 604 }
 605
 606 static ssize_t
 607 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 608 {
 609         int (*func)(struct trace_seq *s) = filp->private_data;
 610         struct trace_seq *s;
 611         int r;
 612
 613         if (*ppos)
 614                 return 0;
 615
 616         s = kmalloc(sizeof(*s), GFP_KERNEL);
 617         if (!s)
 618                 return -ENOMEM;
 619
 620         trace_seq_init(s);
 621
 622         func(s);
 623         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 624
 625         kfree(s);
 626
 627         return r;
 628 }
 629
 630 static const struct seq_operations show_event_seq_ops = {
 631         .start = t_start,
 632         .next = t_next,
 633         .show = t_show,
 634         .stop = t_stop,
 635 };
 636
 637 static const struct seq_operations show_set_event_seq_ops = {
 638         .start = s_start,
 639         .next = s_next,
 640         .show = t_show,
 641         .stop = t_stop,
 642 };
 643
 644 static const struct file_operations ftrace_avail_fops = {
 645         .open = ftrace_event_seq_open,
 646         .read = seq_read,
 647         .llseek = seq_lseek,
 648         .release = seq_release,
 649 };
 650
 651 static const struct file_operations ftrace_set_event_fops = {
 652         .open = ftrace_event_seq_open,
 653         .read = seq_read,
 654         .write = ftrace_event_write,
 655         .llseek = seq_lseek,
 656         .release = seq_release,
 657 };
 658
 659 static const struct file_operations ftrace_enable_fops = {
 660         .open = tracing_open_generic,
 661         .read = event_enable_read,
 662         .write = event_enable_write,
 663 };
 664
 665 static const struct file_operations ftrace_event_format_fops = {
 666         .open = tracing_open_generic,
 667         .read = event_format_read,
 668 };
 669
 670 static const struct file_operations ftrace_event_id_fops = {
 671         .open = tracing_open_generic,
 672         .read = event_id_read,
 673 };
 674
 675 static const struct file_operations ftrace_event_filter_fops = {
 676         .open = tracing_open_generic,
 677         .read = event_filter_read,
 678         .write = event_filter_write,
 679 };
 680
 681 static const struct file_operations ftrace_subsystem_filter_fops = {
 682         .open = tracing_open_generic,
 683         .read = subsystem_filter_read,
 684         .write = subsystem_filter_write,
 685 };
 686
 687 static const struct file_operations ftrace_show_header_fops = {
 688         .open = tracing_open_generic,
 689         .read = show_header,
 690 };
 691
 692 static struct dentry *event_trace_events_dir(void)
 693 {
 694         static struct dentry *d_tracer;
 695         static struct dentry *d_events;
 696
 697         if (d_events)
 698                 return d_events;
 699
 700         d_tracer = tracing_init_dentry();
 701         if (!d_tracer)
 702                 return NULL;
 703
 704         d_events = debugfs_create_dir("events", d_tracer);
 705         if (!d_events)
 706                 pr_warning("Could not create debugfs "
 707                            "'events' directory\n");
 708
 709         return d_events;
 710 }
 711
 712 static LIST_HEAD(event_subsystems);
 713
 714 static struct dentry *
 715 event_subsystem_dir(const char *name, struct dentry *d_events)
 716 {
 717         struct event_subsystem *system;
 718         struct dentry *entry;
 719
 720         /* First see if we did not already create this dir */
 721         list_for_each_entry(system, &event_subsystems, list) {
 722                 if (strcmp(system->name, name) == 0)
 723                         return system->entry;
 724         }
 725
 726         /* need to create new entry */
 727         system = kmalloc(sizeof(*system), GFP_KERNEL);
 728         if (!system) {
 729                 pr_warning("No memory to create event subsystem %s\n",
 730                            name);
 731                 return d_events;
 732         }
 733
 734         system->entry = debugfs_create_dir(name, d_events);
 735         if (!system->entry) {
 736                 pr_warning("Could not create event subsystem %s\n",
 737                            name);
 738                 kfree(system);
 739                 return d_events;
 740         }
 741
 742         system->name = kstrdup(name, GFP_KERNEL);
 743         if (!system->name) {
 744                 debugfs_remove(system->entry);
 745                 kfree(system);
 746                 return d_events;
 747         }
 748
 749         list_add(&system->list, &event_subsystems);
 750
 751         system->filter = NULL;
 752
 753         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
 754         if (!system->filter) {
 755                 pr_warning("Could not allocate filter for subsystem "
 756                            "'%s'\n", name);
 757                 return system->entry;
 758         }
 759
 760         entry = debugfs_create_file("filter", 0644, system->entry, system,
 761                                     &ftrace_subsystem_filter_fops);
 762         if (!entry) {
 763                 kfree(system->filter);
 764                 system->filter = NULL;
 765                 pr_warning("Could not create debugfs "
 766                            "'%s/filter' entry\n", name);
 767         }
 768
 769         return system->entry;
 770 }
 771
 772 static int
 773 event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
 774                  const struct file_operations *id,
 775                  const struct file_operations *enable,
 776                  const struct file_operations *filter,
 777                  const struct file_operations *format)
 778 {
 779         struct dentry *entry;
 780         int ret;
 781
 782         /*
 783          * If the trace point header did not define TRACE_SYSTEM
 784          * then the system would be called "TRACE_SYSTEM".
 785          */
 786         if (strcmp(call->system, TRACE_SYSTEM) != 0)
 787                 d_events = event_subsystem_dir(call->system, d_events);
 788
 789         if (call->raw_init) {
 790                 ret = call->raw_init();
 791                 if (ret < 0) {
 792                         pr_warning("Could not initialize trace point"
 793                                    " events/%s\n", call->name);
 794                         return ret;
 795                 }
 796         }
 797
 798         call->dir = debugfs_create_dir(call->name, d_events);
 799         if (!call->dir) {
 800                 pr_warning("Could not create debugfs "
 801                            "'%s' directory\n", call->name);
 802                 return -1;
 803         }
 804
 805         if (call->regfunc)
 806                 entry = trace_create_file("enable", 0644, call->dir, call,
 807                                           enable);
 808
 809         if (call->id)
 810                 entry = trace_create_file("id", 0444, call->dir, call,
 811                                           id);
 812
 813         if (call->define_fields) {
 814                 ret = call->define_fields();
 815                 if (ret < 0) {
 816                         pr_warning("Could not initialize trace point"
 817                                    " events/%s\n", call->name);
 818                         return ret;
 819                 }
 820                 entry = trace_create_file("filter", 0644, call->dir, call,
 821                                           filter);
 822         }
 823
 824         /* A trace may not want to export its format */
 825         if (!call->show_format)
 826                 return 0;
 827
 828         entry = trace_create_file("format", 0444, call->dir, call,
 829                                   format);
 830
 831         return 0;
 832 }
 833
 834 #define for_each_event(event, start, end)                       \
 835         for (event = start;                                     \
 836              (unsigned long)event < (unsigned long)end;         \
 837              event++)
 838
 839 #ifdef CONFIG_MODULES
 840
 841 static LIST_HEAD(ftrace_module_file_list);
 842
 843 /*
 844  * Modules must own their file_operations to keep up with
 845  * reference counting.
 846  */
 847 struct ftrace_module_file_ops {
 848         struct list_head                list;
 849         struct module                   *mod;
 850         struct file_operations          id;
 851         struct file_operations          enable;
 852         struct file_operations          format;
 853         struct file_operations          filter;
 854 };
 855
 856 static struct ftrace_module_file_ops *
 857 trace_create_file_ops(struct module *mod)
 858 {
 859         struct ftrace_module_file_ops *file_ops;
 860
 861         /*
 862          * This is a bit of a PITA. To allow for correct reference
 863          * counting, modules must "own" their file_operations.
 864          * To do this, we allocate the file operations that will be
 865          * used in the event directory.
 866          */
 867
 868         file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
 869         if (!file_ops)
 870                 return NULL;
 871
 872         file_ops->mod = mod;
 873
 874         file_ops->id = ftrace_event_id_fops;
 875         file_ops->id.owner = mod;
 876
 877         file_ops->enable = ftrace_enable_fops;
 878         file_ops->enable.owner = mod;
 879
 880         file_ops->filter = ftrace_event_filter_fops;
 881         file_ops->filter.owner = mod;
 882
 883         file_ops->format = ftrace_event_format_fops;
 884         file_ops->format.owner = mod;
 885
 886         list_add(&file_ops->list, &ftrace_module_file_list);
 887
 888         return file_ops;
 889 }
 890
 891 static void trace_module_add_events(struct module *mod)
 892 {
 893         struct ftrace_module_file_ops *file_ops = NULL;
 894         struct ftrace_event_call *call, *start, *end;
 895         struct dentry *d_events;
 896
 897         start = mod->trace_events;
 898         end = mod->trace_events + mod->num_trace_events;
 899
 900         if (start == end)
 901                 return;
 902
 903         d_events = event_trace_events_dir();
 904         if (!d_events)
 905                 return;
 906
 907         for_each_event(call, start, end) {
 908                 /* The linker may leave blanks */
 909                 if (!call->name)
 910                         continue;
 911
 912                 /*
 913                  * This module has events, create file ops for this module
 914                  * if not already done.
 915                  */
 916                 if (!file_ops) {
 917                         file_ops = trace_create_file_ops(mod);
 918                         if (!file_ops)
 919                                 return;
 920                 }
 921                 call->mod = mod;
 922                 list_add(&call->list, &ftrace_events);
 923                 event_create_dir(call, d_events,
 924                                  &file_ops->id, &file_ops->enable,
 925                                  &file_ops->filter, &file_ops->format);
 926         }
 927 }
 928
 929 static void trace_module_remove_events(struct module *mod)
 930 {
 931         struct ftrace_module_file_ops *file_ops;
 932         struct ftrace_event_call *call, *p;
 933
 934         list_for_each_entry_safe(call, p, &ftrace_events, list) {
 935                 if (call->mod == mod) {
 936                         if (call->enabled) {
 937                                 call->enabled = 0;
 938                                 call->unregfunc();
 939                         }
 940                         if (call->event)
 941                                 unregister_ftrace_event(call->event);
 942                         debugfs_remove_recursive(call->dir);
 943                         list_del(&call->list);
 944                         trace_destroy_fields(call);
 945                         destroy_preds(call);
 946                 }
 947         }
 948
 949         /* Now free the file_operations */
 950         list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
 951                 if (file_ops->mod == mod)
 952                         break;
 953         }
 954         if (&file_ops->list != &ftrace_module_file_list) {
 955                 list_del(&file_ops->list);
 956                 kfree(file_ops);
 957         }
 958 }
 959
 960 static int trace_module_notify(struct notifier_block *self,
 961                                unsigned long val, void *data)
 962 {
 963         struct module *mod = data;
 964
 965         mutex_lock(&event_mutex);
 966         switch (val) {
 967         case MODULE_STATE_COMING:
 968                 trace_module_add_events(mod);
 969                 break;
 970         case MODULE_STATE_GOING:
 971                 trace_module_remove_events(mod);
 972                 break;
 973         }
 974         mutex_unlock(&event_mutex);
 975
 976         return 0;
 977 }
 978 #else
 979 static int trace_module_notify(struct notifier_block *self,
 980                                unsigned long val, void *data)
 981 {
 982         return 0;
 983 }
 984 #endif /* CONFIG_MODULES */
 985
 986 struct notifier_block trace_module_nb = {
 987         .notifier_call = trace_module_notify,
 988         .priority = 0,
 989 };
 990
 991 extern struct ftrace_event_call __start_ftrace_events[];
 992 extern struct ftrace_event_call __stop_ftrace_events[];
 993
 994 static __init int event_trace_init(void)
 995 {
 996         struct ftrace_event_call *call;
 997         struct dentry *d_tracer;
 998         struct dentry *entry;
 999         struct dentry *d_events;
1000         int ret;
1001
1002         d_tracer = tracing_init_dentry();
1003         if (!d_tracer)
1004                 return 0;
1005
1006         entry = debugfs_create_file("available_events", 0444, d_tracer,
1007                                     (void *)&show_event_seq_ops,
1008                                     &ftrace_avail_fops);
1009         if (!entry)
1010                 pr_warning("Could not create debugfs "
1011                            "'available_events' entry\n");
1012
1013         entry = debugfs_create_file("set_event", 0644, d_tracer,
1014                                     (void *)&show_set_event_seq_ops,
1015                                     &ftrace_set_event_fops);
1016         if (!entry)
1017                 pr_warning("Could not create debugfs "
1018                            "'set_event' entry\n");
1019
1020         d_events = event_trace_events_dir();
1021         if (!d_events)
1022                 return 0;
1023
1024         /* ring buffer internal formats */
1025         trace_create_file("header_page", 0444, d_events,
1026                           ring_buffer_print_page_header,
1027                           &ftrace_show_header_fops);
1028
1029         trace_create_file("header_event", 0444, d_events,
1030                           ring_buffer_print_entry_header,
1031                           &ftrace_show_header_fops);
1032
1033         for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
1034                 /* The linker may leave blanks */
1035                 if (!call->name)
1036                         continue;
1037                 list_add(&call->list, &ftrace_events);
1038                 event_create_dir(call, d_events, &ftrace_event_id_fops,
1039                                  &ftrace_enable_fops, &ftrace_event_filter_fops,
1040                                  &ftrace_event_format_fops);
1041         }
1042
1043         ret = register_module_notifier(&trace_module_nb);
1044         if (!ret)
1045                 pr_warning("Failed to register trace events module notifier\n");
1046
1047         return 0;
1048 }
1049 fs_initcall(event_trace_init);
1050
1051 #ifdef CONFIG_FTRACE_STARTUP_TEST
1052
1053 static DEFINE_SPINLOCK(test_spinlock);
1054 static DEFINE_SPINLOCK(test_spinlock_irq);
1055 static DEFINE_MUTEX(test_mutex);
1056
1057 static __init void test_work(struct work_struct *dummy)
1058 {
1059         spin_lock(&test_spinlock);
1060         spin_lock_irq(&test_spinlock_irq);
1061         udelay(1);
1062         spin_unlock_irq(&test_spinlock_irq);
1063         spin_unlock(&test_spinlock);
1064
1065         mutex_lock(&test_mutex);
1066         msleep(1);
1067         mutex_unlock(&test_mutex);
1068 }
1069
1070 static __init int event_test_thread(void *unused)
1071 {
1072         void *test_malloc;
1073
1074         test_malloc = kmalloc(1234, GFP_KERNEL);
1075         if (!test_malloc)
1076                 pr_info("failed to kmalloc\n");
1077
1078         schedule_on_each_cpu(test_work);
1079
1080         kfree(test_malloc);
1081
1082         set_current_state(TASK_INTERRUPTIBLE);
1083         while (!kthread_should_stop())
1084                 schedule();
1085
1086         return 0;
1087 }
1088
1089 /*
1090  * Do various things that may trigger events.
1091  */
1092 static __init void event_test_stuff(void)
1093 {
1094         struct task_struct *test_thread;
1095
1096         test_thread = kthread_run(event_test_thread, NULL, "test-events");
1097         msleep(1);
1098         kthread_stop(test_thread);
1099 }
1100
1101 /*
1102  * For every trace event defined, we will test each trace point separately,
1103  * and then by groups, and finally all trace points.
1104  */
1105 static __init void event_trace_self_tests(void)
1106 {
1107         struct ftrace_event_call *call;
1108         struct event_subsystem *system;
1109         char *sysname;
1110         int ret;
1111
1112         pr_info("Running tests on trace events:\n");
1113
1114         list_for_each_entry(call, &ftrace_events, list) {
1115
1116                 /* Only test those that have a regfunc */
1117                 if (!call->regfunc)
1118                         continue;
1119
1120                 pr_info("Testing event %s: ", call->name);
1121
1122                 /*
1123                  * If an event is already enabled, someone is using
1124                  * it and the self test should not be on.
1125                  */
1126                 if (call->enabled) {
1127                         pr_warning("Enabled event during self test!\n");
1128                         WARN_ON_ONCE(1);
1129                         continue;
1130                 }
1131
1132                 call->enabled = 1;
1133                 call->regfunc();
1134
1135                 event_test_stuff();
1136
1137                 call->unregfunc();
1138                 call->enabled = 0;
1139
1140                 pr_cont("OK\n");
1141         }
1142
1143         /* Now test at the sub system level */
1144
1145         pr_info("Running tests on trace event systems:\n");
1146
1147         list_for_each_entry(system, &event_subsystems, list) {
1148
1149                 /* the ftrace system is special, skip it */
1150                 if (strcmp(system->name, "ftrace") == 0)
1151                         continue;
1152
1153                 pr_info("Testing event system %s: ", system->name);
1154
1155                 /* ftrace_set_clr_event can modify the name passed in. */
1156                 sysname = kstrdup(system->name, GFP_KERNEL);
1157                 if (WARN_ON(!sysname)) {
1158                         pr_warning("Can't allocate memory, giving up!\n");
1159                         return;
1160                 }
1161                 ret = ftrace_set_clr_event(sysname, 1);
1162                 kfree(sysname);
1163                 if (WARN_ON_ONCE(ret)) {
1164                         pr_warning("error enabling system %s\n",
1165                                    system->name);
1166                         continue;
1167                 }
1168
1169                 event_test_stuff();
1170
1171                 sysname = kstrdup(system->name, GFP_KERNEL);
1172                 if (WARN_ON(!sysname)) {
1173                         pr_warning("Can't allocate memory, giving up!\n");
1174                         return;
1175                 }
1176                 ret = ftrace_set_clr_event(sysname, 0);
1177                 kfree(sysname);
1178
1179                 if (WARN_ON_ONCE(ret))
1180                         pr_warning("error disabling system %s\n",
1181                                    system->name);
1182
1183                 pr_cont("OK\n");
1184         }
1185
1186         /* Test with all events enabled */
1187
1188         pr_info("Running tests on all trace events:\n");
1189         pr_info("Testing all events: ");
1190
1191         sysname = kmalloc(4, GFP_KERNEL);
1192         if (WARN_ON(!sysname)) {
1193                 pr_warning("Can't allocate memory, giving up!\n");
1194                 return;
1195         }
1196         memcpy(sysname, "*:*", 4);
1197         ret = ftrace_set_clr_event(sysname, 1);
1198         if (WARN_ON_ONCE(ret)) {
1199                 kfree(sysname);
1200                 pr_warning("error enabling all events\n");
1201                 return;
1202         }
1203
1204         event_test_stuff();
1205
1206         /* reset sysname */
1207         memcpy(sysname, "*:*", 4);
1208         ret = ftrace_set_clr_event(sysname, 0);
1209         kfree(sysname);
1210
1211         if (WARN_ON_ONCE(ret)) {
1212                 pr_warning("error disabling all events\n");
1213                 return;
1214         }
1215
1216         pr_cont("OK\n");
1217 }
1218
1219 #ifdef CONFIG_FUNCTION_TRACER
1220
1221 static DEFINE_PER_CPU(atomic_t, test_event_disable);
1222
1223 static void
1224 function_test_events_call(unsigned long ip, unsigned long parent_ip)
1225 {
1226         struct ring_buffer_event *event;
1227         struct ftrace_entry *entry;
1228         unsigned long flags;
1229         long disabled;
1230         int resched;
1231         int cpu;
1232         int pc;
1233
1234         pc = preempt_count();
1235         resched = ftrace_preempt_disable();
1236         cpu = raw_smp_processor_id();
1237         disabled = atomic_inc_return(&per_cpu(test_event_disable, cpu));
1238
1239         if (disabled != 1)
1240                 goto out;
1241
1242         local_save_flags(flags);
1243
1244         event = trace_current_buffer_lock_reserve(TRACE_FN, sizeof(*entry),
1245                                                   flags, pc);
1246         if (!event)
1247                 goto out;
1248         entry   = ring_buffer_event_data(event);
1249         entry->ip                       = ip;
1250         entry->parent_ip                = parent_ip;
1251
1252         trace_nowake_buffer_unlock_commit(event, flags, pc);
1253
1254  out:
1255         atomic_dec(&per_cpu(test_event_disable, cpu));
1256         ftrace_preempt_enable(resched);
1257 }
1258
1259 static struct ftrace_ops trace_ops __initdata  =
1260 {
1261         .func = function_test_events_call,
1262 };
1263
1264 static __init void event_trace_self_test_with_function(void)
1265 {
1266         register_ftrace_function(&trace_ops);
1267         pr_info("Running tests again, along with the function tracer\n");
1268         event_trace_self_tests();
1269         unregister_ftrace_function(&trace_ops);
1270 }
1271 #else
1272 static __init void event_trace_self_test_with_function(void)
1273 {
1274 }
1275 #endif
1276
1277 static __init int event_trace_self_tests_init(void)
1278 {
1279
1280         event_trace_self_tests();
1281
1282         event_trace_self_test_with_function();
1283
1284         return 0;
1285 }
1286
1287 late_initcall(event_trace_self_tests_init);
1288
1289 #endif