git.oblomov.eu Git - linux-2.6/blob - 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 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         mutex_lock(&event_mutex);
  84         list_for_each_entry(call, &ftrace_events, list) {
  85
  86                 if (call->enabled) {
  87                         call->enabled = 0;
  88                         call->unregfunc();
  89                 }
  90         }
  91         mutex_unlock(&event_mutex);
  92 }
  93
  94 static void ftrace_event_enable_disable(struct ftrace_event_call *call,
  95                                         int enable)
  96 {
  97
  98         switch (enable) {
  99         case 0:
 100                 if (call->enabled) {
 101                         call->enabled = 0;
 102                         call->unregfunc();
 103                 }
 104                 break;
 105         case 1:
 106                 if (!call->enabled) {
 107                         call->enabled = 1;
 108                         call->regfunc();
 109                 }
 110                 break;
 111         }
 112 }
 113
 114 static int ftrace_set_clr_event(char *buf, int set)
 115 {
 116         struct ftrace_event_call *call;
 117         char *event = NULL, *sub = NULL, *match;
 118         int ret = -EINVAL;
 119
 120         /*
 121          * The buf format can be <subsystem>:<event-name>
 122          *  *:<event-name> means any event by that name.
 123          *  :<event-name> is the same.
 124          *
 125          *  <subsystem>:* means all events in that subsystem
 126          *  <subsystem>: means the same.
 127          *
 128          *  <name> (no ':') means all events in a subsystem with
 129          *  the name <name> or any event that matches <name>
 130          */
 131
 132         match = strsep(&buf, ":");
 133         if (buf) {
 134                 sub = match;
 135                 event = buf;
 136                 match = NULL;
 137
 138                 if (!strlen(sub) || strcmp(sub, "*") == 0)
 139                         sub = NULL;
 140                 if (!strlen(event) || strcmp(event, "*") == 0)
 141                         event = NULL;
 142         }
 143
 144         mutex_lock(&event_mutex);
 145         list_for_each_entry(call, &ftrace_events, list) {
 146
 147                 if (!call->name || !call->regfunc)
 148                         continue;
 149
 150                 if (match &&
 151                     strcmp(match, call->name) != 0 &&
 152                     strcmp(match, call->system) != 0)
 153                         continue;
 154
 155                 if (sub && strcmp(sub, call->system) != 0)
 156                         continue;
 157
 158                 if (event && strcmp(event, call->name) != 0)
 159                         continue;
 160
 161                 ftrace_event_enable_disable(call, set);
 162
 163                 ret = 0;
 164         }
 165         mutex_unlock(&event_mutex);
 166
 167         return ret;
 168 }
 169
 170 /* 128 should be much more than enough */
 171 #define EVENT_BUF_SIZE          127
 172
 173 static ssize_t
 174 ftrace_event_write(struct file *file, const char __user *ubuf,
 175                    size_t cnt, loff_t *ppos)
 176 {
 177         size_t read = 0;
 178         int i, set = 1;
 179         ssize_t ret;
 180         char *buf;
 181         char ch;
 182
 183         if (!cnt || cnt < 0)
 184                 return 0;
 185
 186         ret = tracing_update_buffers();
 187         if (ret < 0)
 188                 return ret;
 189
 190         ret = get_user(ch, ubuf++);
 191         if (ret)
 192                 return ret;
 193         read++;
 194         cnt--;
 195
 196         /* skip white space */
 197         while (cnt && isspace(ch)) {
 198                 ret = get_user(ch, ubuf++);
 199                 if (ret)
 200                         return ret;
 201                 read++;
 202                 cnt--;
 203         }
 204
 205         /* Only white space found? */
 206         if (isspace(ch)) {
 207                 file->f_pos += read;
 208                 ret = read;
 209                 return ret;
 210         }
 211
 212         buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
 213         if (!buf)
 214                 return -ENOMEM;
 215
 216         if (cnt > EVENT_BUF_SIZE)
 217                 cnt = EVENT_BUF_SIZE;
 218
 219         i = 0;
 220         while (cnt && !isspace(ch)) {
 221                 if (!i && ch == '!')
 222                         set = 0;
 223                 else
 224                         buf[i++] = ch;
 225
 226                 ret = get_user(ch, ubuf++);
 227                 if (ret)
 228                         goto out_free;
 229                 read++;
 230                 cnt--;
 231         }
 232         buf[i] = 0;
 233
 234         file->f_pos += read;
 235
 236         ret = ftrace_set_clr_event(buf, set);
 237         if (ret)
 238                 goto out_free;
 239
 240         ret = read;
 241
 242  out_free:
 243         kfree(buf);
 244
 245         return ret;
 246 }
 247
 248 static void *
 249 t_next(struct seq_file *m, void *v, loff_t *pos)
 250 {
 251         struct list_head *list = m->private;
 252         struct ftrace_event_call *call;
 253
 254         (*pos)++;
 255
 256         for (;;) {
 257                 if (list == &ftrace_events)
 258                         return NULL;
 259
 260                 call = list_entry(list, struct ftrace_event_call, list);
 261
 262                 /*
 263                  * The ftrace subsystem is for showing formats only.
 264                  * They can not be enabled or disabled via the event files.
 265                  */
 266                 if (call->regfunc)
 267                         break;
 268
 269                 list = list->next;
 270         }
 271
 272         m->private = list->next;
 273
 274         return call;
 275 }
 276
 277 static void *t_start(struct seq_file *m, loff_t *pos)
 278 {
 279         mutex_lock(&event_mutex);
 280         if (*pos == 0)
 281                 m->private = ftrace_events.next;
 282         return t_next(m, NULL, pos);
 283 }
 284
 285 static void *
 286 s_next(struct seq_file *m, void *v, loff_t *pos)
 287 {
 288         struct list_head *list = m->private;
 289         struct ftrace_event_call *call;
 290
 291         (*pos)++;
 292
 293  retry:
 294         if (list == &ftrace_events)
 295                 return NULL;
 296
 297         call = list_entry(list, struct ftrace_event_call, list);
 298
 299         if (!call->enabled) {
 300                 list = list->next;
 301                 goto retry;
 302         }
 303
 304         m->private = list->next;
 305
 306         return call;
 307 }
 308
 309 static void *s_start(struct seq_file *m, loff_t *pos)
 310 {
 311         mutex_lock(&event_mutex);
 312         if (*pos == 0)
 313                 m->private = ftrace_events.next;
 314         return s_next(m, NULL, pos);
 315 }
 316
 317 static int t_show(struct seq_file *m, void *v)
 318 {
 319         struct ftrace_event_call *call = v;
 320
 321         if (strcmp(call->system, TRACE_SYSTEM) != 0)
 322                 seq_printf(m, "%s:", call->system);
 323         seq_printf(m, "%s\n", call->name);
 324
 325         return 0;
 326 }
 327
 328 static void t_stop(struct seq_file *m, void *p)
 329 {
 330         mutex_unlock(&event_mutex);
 331 }
 332
 333 static int
 334 ftrace_event_seq_open(struct inode *inode, struct file *file)
 335 {
 336         const struct seq_operations *seq_ops;
 337
 338         if ((file->f_mode & FMODE_WRITE) &&
 339             !(file->f_flags & O_APPEND))
 340                 ftrace_clear_events();
 341
 342         seq_ops = inode->i_private;
 343         return seq_open(file, seq_ops);
 344 }
 345
 346 static ssize_t
 347 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
 348                   loff_t *ppos)
 349 {
 350         struct ftrace_event_call *call = filp->private_data;
 351         char *buf;
 352
 353         if (call->enabled)
 354                 buf = "1\n";
 355         else
 356                 buf = "0\n";
 357
 358         return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
 359 }
 360
 361 static ssize_t
 362 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 363                    loff_t *ppos)
 364 {
 365         struct ftrace_event_call *call = filp->private_data;
 366         char buf[64];
 367         unsigned long val;
 368         int ret;
 369
 370         if (cnt >= sizeof(buf))
 371                 return -EINVAL;
 372
 373         if (copy_from_user(&buf, ubuf, cnt))
 374                 return -EFAULT;
 375
 376         buf[cnt] = 0;
 377
 378         ret = strict_strtoul(buf, 10, &val);
 379         if (ret < 0)
 380                 return ret;
 381
 382         ret = tracing_update_buffers();
 383         if (ret < 0)
 384                 return ret;
 385
 386         switch (val) {
 387         case 0:
 388         case 1:
 389                 mutex_lock(&event_mutex);
 390                 ftrace_event_enable_disable(call, val);
 391                 mutex_unlock(&event_mutex);
 392                 break;
 393
 394         default:
 395                 return -EINVAL;
 396         }
 397
 398         *ppos += cnt;
 399
 400         return cnt;
 401 }
 402
 403 extern char *__bad_type_size(void);
 404
 405 #undef FIELD
 406 #define FIELD(type, name)                                               \
 407         sizeof(type) != sizeof(field.name) ? __bad_type_size() :        \
 408         #type, "common_" #name, offsetof(typeof(field), name),          \
 409                 sizeof(field.name)
 410
 411 static int trace_write_header(struct trace_seq *s)
 412 {
 413         struct trace_entry field;
 414
 415         /* struct trace_entry */
 416         return trace_seq_printf(s,
 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                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
 421                                 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
 422                                 "\n",
 423                                 FIELD(unsigned short, type),
 424                                 FIELD(unsigned char, flags),
 425                                 FIELD(unsigned char, preempt_count),
 426                                 FIELD(int, pid),
 427                                 FIELD(int, tgid));
 428 }
 429
 430 static ssize_t
 431 event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
 432                   loff_t *ppos)
 433 {
 434         struct ftrace_event_call *call = filp->private_data;
 435         struct trace_seq *s;
 436         char *buf;
 437         int r;
 438
 439         if (*ppos)
 440                 return 0;
 441
 442         s = kmalloc(sizeof(*s), GFP_KERNEL);
 443         if (!s)
 444                 return -ENOMEM;
 445
 446         trace_seq_init(s);
 447
 448         /* If any of the first writes fail, so will the show_format. */
 449
 450         trace_seq_printf(s, "name: %s\n", call->name);
 451         trace_seq_printf(s, "ID: %d\n", call->id);
 452         trace_seq_printf(s, "format:\n");
 453         trace_write_header(s);
 454
 455         r = call->show_format(s);
 456         if (!r) {
 457                 /*
 458                  * ug!  The format output is bigger than a PAGE!!
 459                  */
 460                 buf = "FORMAT TOO BIG\n";
 461                 r = simple_read_from_buffer(ubuf, cnt, ppos,
 462                                               buf, strlen(buf));
 463                 goto out;
 464         }
 465
 466         r = simple_read_from_buffer(ubuf, cnt, ppos,
 467                                     s->buffer, s->len);
 468  out:
 469         kfree(s);
 470         return r;
 471 }
 472
 473 static ssize_t
 474 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 475 {
 476         struct ftrace_event_call *call = filp->private_data;
 477         struct trace_seq *s;
 478         int r;
 479
 480         if (*ppos)
 481                 return 0;
 482
 483         s = kmalloc(sizeof(*s), GFP_KERNEL);
 484         if (!s)
 485                 return -ENOMEM;
 486
 487         trace_seq_init(s);
 488         trace_seq_printf(s, "%d\n", call->id);
 489
 490         r = simple_read_from_buffer(ubuf, cnt, ppos,
 491                                     s->buffer, s->len);
 492         kfree(s);
 493         return r;
 494 }
 495
 496 static ssize_t
 497 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 498                   loff_t *ppos)
 499 {
 500         struct ftrace_event_call *call = filp->private_data;
 501         struct trace_seq *s;
 502         int r;
 503
 504         if (*ppos)
 505                 return 0;
 506
 507         s = kmalloc(sizeof(*s), GFP_KERNEL);
 508         if (!s)
 509                 return -ENOMEM;
 510
 511         trace_seq_init(s);
 512
 513         print_event_filter(call, s);
 514         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 515
 516         kfree(s);
 517
 518         return r;
 519 }
 520
 521 static ssize_t
 522 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 523                    loff_t *ppos)
 524 {
 525         struct ftrace_event_call *call = filp->private_data;
 526         char *buf;
 527         int err;
 528
 529         if (cnt >= PAGE_SIZE)
 530                 return -EINVAL;
 531
 532         buf = (char *)__get_free_page(GFP_TEMPORARY);
 533         if (!buf)
 534                 return -ENOMEM;
 535
 536         if (copy_from_user(buf, ubuf, cnt)) {
 537                 free_page((unsigned long) buf);
 538                 return -EFAULT;
 539         }
 540         buf[cnt] = '\0';
 541
 542         err = apply_event_filter(call, buf);
 543         free_page((unsigned long) buf);
 544         if (err < 0)
 545                 return err;
 546
 547         *ppos += cnt;
 548
 549         return cnt;
 550 }
 551
 552 static ssize_t
 553 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 554                       loff_t *ppos)
 555 {
 556         struct event_subsystem *system = filp->private_data;
 557         struct trace_seq *s;
 558         int r;
 559
 560         if (*ppos)
 561                 return 0;
 562
 563         s = kmalloc(sizeof(*s), GFP_KERNEL);
 564         if (!s)
 565                 return -ENOMEM;
 566
 567         trace_seq_init(s);
 568
 569         print_subsystem_event_filter(system, s);
 570         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 571
 572         kfree(s);
 573
 574         return r;
 575 }
 576
 577 static ssize_t
 578 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 579                        loff_t *ppos)
 580 {
 581         struct event_subsystem *system = filp->private_data;
 582         char *buf;
 583         int err;
 584
 585         if (cnt >= PAGE_SIZE)
 586                 return -EINVAL;
 587
 588         buf = (char *)__get_free_page(GFP_TEMPORARY);
 589         if (!buf)
 590                 return -ENOMEM;
 591
 592         if (copy_from_user(buf, ubuf, cnt)) {
 593                 free_page((unsigned long) buf);
 594                 return -EFAULT;
 595         }
 596         buf[cnt] = '\0';
 597
 598         err = apply_subsystem_event_filter(system, buf);
 599         free_page((unsigned long) buf);
 600         if (err < 0)
 601                 return err;
 602
 603         *ppos += cnt;
 604
 605         return cnt;
 606 }
 607
 608 static ssize_t
 609 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 610 {
 611         int (*func)(struct trace_seq *s) = filp->private_data;
 612         struct trace_seq *s;
 613         int r;
 614
 615         if (*ppos)
 616                 return 0;
 617
 618         s = kmalloc(sizeof(*s), GFP_KERNEL);
 619         if (!s)
 620                 return -ENOMEM;
 621
 622         trace_seq_init(s);
 623
 624         func(s);
 625         r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 626
 627         kfree(s);
 628
 629         return r;
 630 }
 631
 632 static const struct seq_operations show_event_seq_ops = {
 633         .start = t_start,
 634         .next = t_next,
 635         .show = t_show,
 636         .stop = t_stop,
 637 };
 638
 639 static const struct seq_operations show_set_event_seq_ops = {
 640         .start = s_start,
 641         .next = s_next,
 642         .show = t_show,
 643         .stop = t_stop,
 644 };
 645
 646 static const struct file_operations ftrace_avail_fops = {
 647         .open = ftrace_event_seq_open,
 648         .read = seq_read,
 649         .llseek = seq_lseek,
 650         .release = seq_release,
 651 };
 652
 653 static const struct file_operations ftrace_set_event_fops = {
 654         .open = ftrace_event_seq_open,
 655         .read = seq_read,
 656         .write = ftrace_event_write,
 657         .llseek = seq_lseek,
 658         .release = seq_release,
 659 };
 660
 661 static const struct file_operations ftrace_enable_fops = {
 662         .open = tracing_open_generic,
 663         .read = event_enable_read,
 664         .write = event_enable_write,
 665 };
 666
 667 static const struct file_operations ftrace_event_format_fops = {
 668         .open = tracing_open_generic,
 669         .read = event_format_read,
 670 };
 671
 672 static const struct file_operations ftrace_event_id_fops = {
 673         .open = tracing_open_generic,
 674         .read = event_id_read,
 675 };
 676
 677 static const struct file_operations ftrace_event_filter_fops = {
 678         .open = tracing_open_generic,
 679         .read = event_filter_read,
 680         .write = event_filter_write,
 681 };
 682
 683 static const struct file_operations ftrace_subsystem_filter_fops = {
 684         .open = tracing_open_generic,
 685         .read = subsystem_filter_read,
 686         .write = subsystem_filter_write,
 687 };
 688
 689 static const struct file_operations ftrace_show_header_fops = {
 690         .open = tracing_open_generic,
 691         .read = show_header,
 692 };
 693
 694 static struct dentry *event_trace_events_dir(void)
 695 {
 696         static struct dentry *d_tracer;
 697         static struct dentry *d_events;
 698
 699         if (d_events)
 700                 return d_events;
 701
 702         d_tracer = tracing_init_dentry();
 703         if (!d_tracer)
 704                 return NULL;
 705
 706         d_events = debugfs_create_dir("events", d_tracer);
 707         if (!d_events)
 708                 pr_warning("Could not create debugfs "
 709                            "'events' directory\n");
 710
 711         return d_events;
 712 }
 713
 714 static LIST_HEAD(event_subsystems);
 715
 716 static struct dentry *
 717 event_subsystem_dir(const char *name, struct dentry *d_events)
 718 {
 719         struct event_subsystem *system;
 720         struct dentry *entry;
 721
 722         /* First see if we did not already create this dir */
 723         list_for_each_entry(system, &event_subsystems, list) {
 724                 if (strcmp(system->name, name) == 0)
 725                         return system->entry;
 726         }
 727
 728         /* need to create new entry */
 729         system = kmalloc(sizeof(*system), GFP_KERNEL);
 730         if (!system) {
 731                 pr_warning("No memory to create event subsystem %s\n",
 732                            name);
 733                 return d_events;
 734         }
 735
 736         system->entry = debugfs_create_dir(name, d_events);
 737         if (!system->entry) {
 738                 pr_warning("Could not create event subsystem %s\n",
 739                            name);
 740                 kfree(system);
 741                 return d_events;
 742         }
 743
 744         system->name = kstrdup(name, GFP_KERNEL);
 745         if (!system->name) {
 746                 debugfs_remove(system->entry);
 747                 kfree(system);
 748                 return d_events;
 749         }
 750
 751         list_add(&system->list, &event_subsystems);
 752
 753         system->filter = NULL;
 754
 755         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
 756         if (!system->filter) {
 757                 pr_warning("Could not allocate filter for subsystem "
 758                            "'%s'\n", name);
 759                 return system->entry;
 760         }
 761
 762         entry = debugfs_create_file("filter", 0644, system->entry, system,
 763                                     &ftrace_subsystem_filter_fops);
 764         if (!entry) {
 765                 kfree(system->filter);
 766                 system->filter = NULL;
 767                 pr_warning("Could not create debugfs "
 768                            "'%s/filter' entry\n", name);
 769         }
 770
 771         return system->entry;
 772 }
 773
 774 static int
 775 event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
 776                  const struct file_operations *id,
 777                  const struct file_operations *enable,
 778                  const struct file_operations *filter,
 779                  const struct file_operations *format)
 780 {
 781         struct dentry *entry;
 782         int ret;
 783
 784         /*
 785          * If the trace point header did not define TRACE_SYSTEM
 786          * then the system would be called "TRACE_SYSTEM".
 787          */
 788         if (strcmp(call->system, TRACE_SYSTEM) != 0)
 789                 d_events = event_subsystem_dir(call->system, d_events);
 790
 791         if (call->raw_init) {
 792                 ret = call->raw_init();
 793                 if (ret < 0) {
 794                         pr_warning("Could not initialize trace point"
 795                                    " events/%s\n", call->name);
 796                         return ret;
 797                 }
 798         }
 799
 800         call->dir = debugfs_create_dir(call->name, d_events);
 801         if (!call->dir) {
 802                 pr_warning("Could not create debugfs "
 803                            "'%s' directory\n", call->name);
 804                 return -1;
 805         }
 806
 807         if (call->regfunc)
 808                 entry = trace_create_file("enable", 0644, call->dir, call,
 809                                           enable);
 810
 811         if (call->id)
 812                 entry = trace_create_file("id", 0444, call->dir, call,
 813                                           id);
 814
 815         if (call->define_fields) {
 816                 ret = call->define_fields();
 817                 if (ret < 0) {
 818                         pr_warning("Could not initialize trace point"
 819                                    " events/%s\n", call->name);
 820                         return ret;
 821                 }
 822                 entry = trace_create_file("filter", 0644, call->dir, call,
 823                                           filter);
 824         }
 825
 826         /* A trace may not want to export its format */
 827         if (!call->show_format)
 828                 return 0;
 829
 830         entry = trace_create_file("format", 0444, call->dir, call,
 831                                   format);
 832
 833         return 0;
 834 }
 835
 836 #define for_each_event(event, start, end)                       \
 837         for (event = start;                                     \
 838              (unsigned long)event < (unsigned long)end;         \
 839              event++)
 840
 841 #ifdef CONFIG_MODULES
 842
 843 static LIST_HEAD(ftrace_module_file_list);
 844
 845 /*
 846  * Modules must own their file_operations to keep up with
 847  * reference counting.
 848  */
 849 struct ftrace_module_file_ops {
 850         struct list_head                list;
 851         struct module                   *mod;
 852         struct file_operations          id;
 853         struct file_operations          enable;
 854         struct file_operations          format;
 855         struct file_operations          filter;
 856 };
 857
 858 static struct ftrace_module_file_ops *
 859 trace_create_file_ops(struct module *mod)
 860 {
 861         struct ftrace_module_file_ops *file_ops;
 862
 863         /*
 864          * This is a bit of a PITA. To allow for correct reference
 865          * counting, modules must "own" their file_operations.
 866          * To do this, we allocate the file operations that will be
 867          * used in the event directory.
 868          */
 869
 870         file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
 871         if (!file_ops)
 872                 return NULL;
 873
 874         file_ops->mod = mod;
 875
 876         file_ops->id = ftrace_event_id_fops;
 877         file_ops->id.owner = mod;
 878
 879         file_ops->enable = ftrace_enable_fops;
 880         file_ops->enable.owner = mod;
 881
 882         file_ops->filter = ftrace_event_filter_fops;
 883         file_ops->filter.owner = mod;
 884
 885         file_ops->format = ftrace_event_format_fops;
 886         file_ops->format.owner = mod;
 887
 888         list_add(&file_ops->list, &ftrace_module_file_list);
 889
 890         return file_ops;
 891 }
 892
 893 static void trace_module_add_events(struct module *mod)
 894 {
 895         struct ftrace_module_file_ops *file_ops = NULL;
 896         struct ftrace_event_call *call, *start, *end;
 897         struct dentry *d_events;
 898
 899         start = mod->trace_events;
 900         end = mod->trace_events + mod->num_trace_events;
 901
 902         if (start == end)
 903                 return;
 904
 905         d_events = event_trace_events_dir();
 906         if (!d_events)
 907                 return;
 908
 909         for_each_event(call, start, end) {
 910                 /* The linker may leave blanks */
 911                 if (!call->name)
 912                         continue;
 913
 914                 /*
 915                  * This module has events, create file ops for this module
 916                  * if not already done.
 917                  */
 918                 if (!file_ops) {
 919                         file_ops = trace_create_file_ops(mod);
 920                         if (!file_ops)
 921                                 return;
 922                 }
 923                 call->mod = mod;
 924                 list_add(&call->list, &ftrace_events);
 925                 event_create_dir(call, d_events,
 926                                  &file_ops->id, &file_ops->enable,
 927                                  &file_ops->filter, &file_ops->format);
 928         }
 929 }
 930
 931 static void trace_module_remove_events(struct module *mod)
 932 {
 933         struct ftrace_module_file_ops *file_ops;
 934         struct ftrace_event_call *call, *p;
 935
 936         list_for_each_entry_safe(call, p, &ftrace_events, list) {
 937                 if (call->mod == mod) {
 938                         if (call->enabled) {
 939                                 call->enabled = 0;
 940                                 call->unregfunc();
 941                         }
 942                         if (call->event)
 943                                 unregister_ftrace_event(call->event);
 944                         debugfs_remove_recursive(call->dir);
 945                         list_del(&call->list);
 946                         trace_destroy_fields(call);
 947                         destroy_preds(call);
 948                 }
 949         }
 950
 951         /* Now free the file_operations */
 952         list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
 953                 if (file_ops->mod == mod)
 954                         break;
 955         }
 956         if (&file_ops->list != &ftrace_module_file_list) {
 957                 list_del(&file_ops->list);
 958                 kfree(file_ops);
 959         }
 960 }
 961
 962 static int trace_module_notify(struct notifier_block *self,
 963                                unsigned long val, void *data)
 964 {
 965         struct module *mod = data;
 966
 967         mutex_lock(&event_mutex);
 968         switch (val) {
 969         case MODULE_STATE_COMING:
 970                 trace_module_add_events(mod);
 971                 break;
 972         case MODULE_STATE_GOING:
 973                 trace_module_remove_events(mod);
 974                 break;
 975         }
 976         mutex_unlock(&event_mutex);
 977
 978         return 0;
 979 }
 980 #else
 981 static int trace_module_notify(struct notifier_block *self,
 982                                unsigned long val, void *data)
 983 {
 984         return 0;
 985 }
 986 #endif /* CONFIG_MODULES */
 987
 988 struct notifier_block trace_module_nb = {
 989         .notifier_call = trace_module_notify,
 990         .priority = 0,
 991 };
 992
 993 extern struct ftrace_event_call __start_ftrace_events[];
 994 extern struct ftrace_event_call __stop_ftrace_events[];
 995
 996 static __init int event_trace_init(void)
 997 {
 998         struct ftrace_event_call *call;
 999         struct dentry *d_tracer;
1000         struct dentry *entry;
1001         struct dentry *d_events;
1002         int ret;
1003
1004         d_tracer = tracing_init_dentry();
1005         if (!d_tracer)
1006                 return 0;
1007
1008         entry = debugfs_create_file("available_events", 0444, d_tracer,
1009                                     (void *)&show_event_seq_ops,
1010                                     &ftrace_avail_fops);
1011         if (!entry)
1012                 pr_warning("Could not create debugfs "
1013                            "'available_events' entry\n");
1014
1015         entry = debugfs_create_file("set_event", 0644, d_tracer,
1016                                     (void *)&show_set_event_seq_ops,
1017                                     &ftrace_set_event_fops);
1018         if (!entry)
1019                 pr_warning("Could not create debugfs "
1020                            "'set_event' entry\n");
1021
1022         d_events = event_trace_events_dir();
1023         if (!d_events)
1024                 return 0;
1025
1026         /* ring buffer internal formats */
1027         trace_create_file("header_page", 0444, d_events,
1028                           ring_buffer_print_page_header,
1029                           &ftrace_show_header_fops);
1030
1031         trace_create_file("header_event", 0444, d_events,
1032                           ring_buffer_print_entry_header,
1033                           &ftrace_show_header_fops);
1034
1035         for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
1036                 /* The linker may leave blanks */
1037                 if (!call->name)
1038                         continue;
1039                 list_add(&call->list, &ftrace_events);
1040                 event_create_dir(call, d_events, &ftrace_event_id_fops,
1041                                  &ftrace_enable_fops, &ftrace_event_filter_fops,
1042                                  &ftrace_event_format_fops);
1043         }
1044
1045         ret = register_module_notifier(&trace_module_nb);
1046         if (!ret)
1047                 pr_warning("Failed to register trace events module notifier\n");
1048
1049         return 0;
1050 }
1051 fs_initcall(event_trace_init);
1052
1053 #ifdef CONFIG_FTRACE_STARTUP_TEST
1054
1055 static DEFINE_SPINLOCK(test_spinlock);
1056 static DEFINE_SPINLOCK(test_spinlock_irq);
1057 static DEFINE_MUTEX(test_mutex);
1058
1059 static __init void test_work(struct work_struct *dummy)
1060 {
1061         spin_lock(&test_spinlock);
1062         spin_lock_irq(&test_spinlock_irq);
1063         udelay(1);
1064         spin_unlock_irq(&test_spinlock_irq);
1065         spin_unlock(&test_spinlock);
1066
1067         mutex_lock(&test_mutex);
1068         msleep(1);
1069         mutex_unlock(&test_mutex);
1070 }
1071
1072 static __init int event_test_thread(void *unused)
1073 {
1074         void *test_malloc;
1075
1076         test_malloc = kmalloc(1234, GFP_KERNEL);
1077         if (!test_malloc)
1078                 pr_info("failed to kmalloc\n");
1079
1080         schedule_on_each_cpu(test_work);
1081
1082         kfree(test_malloc);
1083
1084         set_current_state(TASK_INTERRUPTIBLE);
1085         while (!kthread_should_stop())
1086                 schedule();
1087
1088         return 0;
1089 }
1090
1091 /*
1092  * Do various things that may trigger events.
1093  */
1094 static __init void event_test_stuff(void)
1095 {
1096         struct task_struct *test_thread;
1097
1098         test_thread = kthread_run(event_test_thread, NULL, "test-events");
1099         msleep(1);
1100         kthread_stop(test_thread);
1101 }
1102
1103 /*
1104  * For every trace event defined, we will test each trace point separately,
1105  * and then by groups, and finally all trace points.
1106  */
1107 static __init void event_trace_self_tests(void)
1108 {
1109         struct ftrace_event_call *call;
1110         struct event_subsystem *system;
1111         char *sysname;
1112         int ret;
1113
1114         pr_info("Running tests on trace events:\n");
1115
1116         list_for_each_entry(call, &ftrace_events, list) {
1117
1118                 /* Only test those that have a regfunc */
1119                 if (!call->regfunc)
1120                         continue;
1121
1122                 pr_info("Testing event %s: ", call->name);
1123
1124                 /*
1125                  * If an event is already enabled, someone is using
1126                  * it and the self test should not be on.
1127                  */
1128                 if (call->enabled) {
1129                         pr_warning("Enabled event during self test!\n");
1130                         WARN_ON_ONCE(1);
1131                         continue;
1132                 }
1133
1134                 call->enabled = 1;
1135                 call->regfunc();
1136
1137                 event_test_stuff();
1138
1139                 call->unregfunc();
1140                 call->enabled = 0;
1141
1142                 pr_cont("OK\n");
1143         }
1144
1145         /* Now test at the sub system level */
1146
1147         pr_info("Running tests on trace event systems:\n");
1148
1149         list_for_each_entry(system, &event_subsystems, list) {
1150
1151                 /* the ftrace system is special, skip it */
1152                 if (strcmp(system->name, "ftrace") == 0)
1153                         continue;
1154
1155                 pr_info("Testing event system %s: ", system->name);
1156
1157                 /* ftrace_set_clr_event can modify the name passed in. */
1158                 sysname = kstrdup(system->name, GFP_KERNEL);
1159                 if (WARN_ON(!sysname)) {
1160                         pr_warning("Can't allocate memory, giving up!\n");
1161                         return;
1162                 }
1163                 ret = ftrace_set_clr_event(sysname, 1);
1164                 kfree(sysname);
1165                 if (WARN_ON_ONCE(ret)) {
1166                         pr_warning("error enabling system %s\n",
1167                                    system->name);
1168                         continue;
1169                 }
1170
1171                 event_test_stuff();
1172
1173                 sysname = kstrdup(system->name, GFP_KERNEL);
1174                 if (WARN_ON(!sysname)) {
1175                         pr_warning("Can't allocate memory, giving up!\n");
1176                         return;
1177                 }
1178                 ret = ftrace_set_clr_event(sysname, 0);
1179                 kfree(sysname);
1180
1181                 if (WARN_ON_ONCE(ret))
1182                         pr_warning("error disabling system %s\n",
1183                                    system->name);
1184
1185                 pr_cont("OK\n");
1186         }
1187
1188         /* Test with all events enabled */
1189
1190         pr_info("Running tests on all trace events:\n");
1191         pr_info("Testing all events: ");
1192
1193         sysname = kmalloc(4, GFP_KERNEL);
1194         if (WARN_ON(!sysname)) {
1195                 pr_warning("Can't allocate memory, giving up!\n");
1196                 return;
1197         }
1198         memcpy(sysname, "*:*", 4);
1199         ret = ftrace_set_clr_event(sysname, 1);
1200         if (WARN_ON_ONCE(ret)) {
1201                 kfree(sysname);
1202                 pr_warning("error enabling all events\n");
1203                 return;
1204         }
1205
1206         event_test_stuff();
1207
1208         /* reset sysname */
1209         memcpy(sysname, "*:*", 4);
1210         ret = ftrace_set_clr_event(sysname, 0);
1211         kfree(sysname);
1212
1213         if (WARN_ON_ONCE(ret)) {
1214                 pr_warning("error disabling all events\n");
1215                 return;
1216         }
1217
1218         pr_cont("OK\n");
1219 }
1220
1221 #ifdef CONFIG_FUNCTION_TRACER
1222
1223 static DEFINE_PER_CPU(atomic_t, test_event_disable);
1224
1225 static void
1226 function_test_events_call(unsigned long ip, unsigned long parent_ip)
1227 {
1228         struct ring_buffer_event *event;
1229         struct ftrace_entry *entry;
1230         unsigned long flags;
1231         long disabled;
1232         int resched;
1233         int cpu;
1234         int pc;
1235
1236         pc = preempt_count();
1237         resched = ftrace_preempt_disable();
1238         cpu = raw_smp_processor_id();
1239         disabled = atomic_inc_return(&per_cpu(test_event_disable, cpu));
1240
1241         if (disabled != 1)
1242                 goto out;
1243
1244         local_save_flags(flags);
1245
1246         event = trace_current_buffer_lock_reserve(TRACE_FN, sizeof(*entry),
1247                                                   flags, pc);
1248         if (!event)
1249                 goto out;
1250         entry   = ring_buffer_event_data(event);
1251         entry->ip                       = ip;
1252         entry->parent_ip                = parent_ip;
1253
1254         trace_nowake_buffer_unlock_commit(event, flags, pc);
1255
1256  out:
1257         atomic_dec(&per_cpu(test_event_disable, cpu));
1258         ftrace_preempt_enable(resched);
1259 }
1260
1261 static struct ftrace_ops trace_ops __initdata  =
1262 {
1263         .func = function_test_events_call,
1264 };
1265
1266 static __init void event_trace_self_test_with_function(void)
1267 {
1268         register_ftrace_function(&trace_ops);
1269         pr_info("Running tests again, along with the function tracer\n");
1270         event_trace_self_tests();
1271         unregister_ftrace_function(&trace_ops);
1272 }
1273 #else
1274 static __init void event_trace_self_test_with_function(void)
1275 {
1276 }
1277 #endif
1278
1279 static __init int event_trace_self_tests_init(void)
1280 {
1281
1282         event_trace_self_tests();
1283
1284         event_trace_self_test_with_function();
1285
1286         return 0;
1287 }
1288
1289 late_initcall(event_trace_self_tests_init);
1290
1291 #endif