kernel/kernel/trace/trace_output.c

   1 /*
   2  * trace_output.c
   3  *
   4  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
   5  *
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/mutex.h>
  10 #include <linux/ftrace.h>
  11
  12 #include "trace_output.h"
  13
  14 /* must be a power of 2 */
  15 #define EVENT_HASHSIZE  128
  16
  17 DECLARE_RWSEM(trace_event_sem);
  18
  19 static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
  20
  21 static int next_event_type = __TRACE_LAST_TYPE + 1;
  22
  23 enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
  24 {
  25         struct trace_seq *s = &iter->seq;
  26         struct trace_entry *entry = iter->ent;
  27         struct bputs_entry *field;
  28
  29         trace_assign_type(field, entry);
  30
  31         trace_seq_puts(s, field->str);
  32
  33         return trace_handle_return(s);
  34 }
  35
  36 enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
  37 {
  38         struct trace_seq *s = &iter->seq;
  39         struct trace_entry *entry = iter->ent;
  40         struct bprint_entry *field;
  41
  42         trace_assign_type(field, entry);
  43
  44         trace_seq_bprintf(s, field->fmt, field->buf);
  45
  46         return trace_handle_return(s);
  47 }
  48
  49 enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
  50 {
  51         struct trace_seq *s = &iter->seq;
  52         struct trace_entry *entry = iter->ent;
  53         struct print_entry *field;
  54
  55         trace_assign_type(field, entry);
  56
  57         trace_seq_puts(s, field->buf);
  58
  59         return trace_handle_return(s);
  60 }
  61
  62 const char *
  63 ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
  64                        unsigned long flags,
  65                        const struct trace_print_flags *flag_array)
  66 {
  67         unsigned long mask;
  68         const char *str;
  69         const char *ret = trace_seq_buffer_ptr(p);
  70         int i, first = 1;
  71
  72         for (i = 0;  flag_array[i].name && flags; i++) {
  73
  74                 mask = flag_array[i].mask;
  75                 if ((flags & mask) != mask)
  76                         continue;
  77
  78                 str = flag_array[i].name;
  79                 flags &= ~mask;
  80                 if (!first && delim)
  81                         trace_seq_puts(p, delim);
  82                 else
  83                         first = 0;
  84                 trace_seq_puts(p, str);
  85         }
  86
  87         /* check for left over flags */
  88         if (flags) {
  89                 if (!first && delim)
  90                         trace_seq_puts(p, delim);
  91                 trace_seq_printf(p, "0x%lx", flags);
  92         }
  93
  94         trace_seq_putc(p, 0);
  95
  96         return ret;
  97 }
  98 EXPORT_SYMBOL(ftrace_print_flags_seq);
  99
 100 const char *
 101 ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
 102                          const struct trace_print_flags *symbol_array)
 103 {
 104         int i;
 105         const char *ret = trace_seq_buffer_ptr(p);
 106
 107         for (i = 0;  symbol_array[i].name; i++) {
 108
 109                 if (val != symbol_array[i].mask)
 110                         continue;
 111
 112                 trace_seq_puts(p, symbol_array[i].name);
 113                 break;
 114         }
 115
 116         if (ret == (const char *)(trace_seq_buffer_ptr(p)))
 117                 trace_seq_printf(p, "0x%lx", val);
 118
 119         trace_seq_putc(p, 0);
 120
 121         return ret;
 122 }
 123 EXPORT_SYMBOL(ftrace_print_symbols_seq);
 124
 125 #if BITS_PER_LONG == 32
 126 const char *
 127 ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
 128                          const struct trace_print_flags_u64 *symbol_array)
 129 {
 130         int i;
 131         const char *ret = trace_seq_buffer_ptr(p);
 132
 133         for (i = 0;  symbol_array[i].name; i++) {
 134
 135                 if (val != symbol_array[i].mask)
 136                         continue;
 137
 138                 trace_seq_puts(p, symbol_array[i].name);
 139                 break;
 140         }
 141
 142         if (ret == (const char *)(trace_seq_buffer_ptr(p)))
 143                 trace_seq_printf(p, "0x%llx", val);
 144
 145         trace_seq_putc(p, 0);
 146
 147         return ret;
 148 }
 149 EXPORT_SYMBOL(ftrace_print_symbols_seq_u64);
 150 #endif
 151
 152 const char *
 153 ftrace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
 154                          unsigned int bitmask_size)
 155 {
 156         const char *ret = trace_seq_buffer_ptr(p);
 157
 158         trace_seq_bitmask(p, bitmask_ptr, bitmask_size * 8);
 159         trace_seq_putc(p, 0);
 160
 161         return ret;
 162 }
 163 EXPORT_SYMBOL_GPL(ftrace_print_bitmask_seq);
 164
 165 const char *
 166 ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
 167 {
 168         int i;
 169         const char *ret = trace_seq_buffer_ptr(p);
 170
 171         for (i = 0; i < buf_len; i++)
 172                 trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
 173
 174         trace_seq_putc(p, 0);
 175
 176         return ret;
 177 }
 178 EXPORT_SYMBOL(ftrace_print_hex_seq);
 179
 180 const char *
 181 ftrace_print_array_seq(struct trace_seq *p, const void *buf, int count,
 182                        size_t el_size)
 183 {
 184         const char *ret = trace_seq_buffer_ptr(p);
 185         const char *prefix = "";
 186         void *ptr = (void *)buf;
 187         size_t buf_len = count * el_size;
 188
 189         trace_seq_putc(p, '{');
 190
 191         while (ptr < buf + buf_len) {
 192                 switch (el_size) {
 193                 case 1:
 194                         trace_seq_printf(p, "%s0x%x", prefix,
 195                                          *(u8 *)ptr);
 196                         break;
 197                 case 2:
 198                         trace_seq_printf(p, "%s0x%x", prefix,
 199                                          *(u16 *)ptr);
 200                         break;
 201                 case 4:
 202                         trace_seq_printf(p, "%s0x%x", prefix,
 203                                          *(u32 *)ptr);
 204                         break;
 205                 case 8:
 206                         trace_seq_printf(p, "%s0x%llx", prefix,
 207                                          *(u64 *)ptr);
 208                         break;
 209                 default:
 210                         trace_seq_printf(p, "BAD SIZE:%zu 0x%x", el_size,
 211                                          *(u8 *)ptr);
 212                         el_size = 1;
 213                 }
 214                 prefix = ",";
 215                 ptr += el_size;
 216         }
 217
 218         trace_seq_putc(p, '}');
 219         trace_seq_putc(p, 0);
 220
 221         return ret;
 222 }
 223 EXPORT_SYMBOL(ftrace_print_array_seq);
 224
 225 int ftrace_raw_output_prep(struct trace_iterator *iter,
 226                            struct trace_event *trace_event)
 227 {
 228         struct ftrace_event_call *event;
 229         struct trace_seq *s = &iter->seq;
 230         struct trace_seq *p = &iter->tmp_seq;
 231         struct trace_entry *entry;
 232
 233         event = container_of(trace_event, struct ftrace_event_call, event);
 234         entry = iter->ent;
 235
 236         if (entry->type != event->event.type) {
 237                 WARN_ON_ONCE(1);
 238                 return TRACE_TYPE_UNHANDLED;
 239         }
 240
 241         trace_seq_init(p);
 242         trace_seq_printf(s, "%s: ", ftrace_event_name(event));
 243
 244         return trace_handle_return(s);
 245 }
 246 EXPORT_SYMBOL(ftrace_raw_output_prep);
 247
 248 static int ftrace_output_raw(struct trace_iterator *iter, char *name,
 249                              char *fmt, va_list ap)
 250 {
 251         struct trace_seq *s = &iter->seq;
 252
 253         trace_seq_printf(s, "%s: ", name);
 254         trace_seq_vprintf(s, fmt, ap);
 255
 256         return trace_handle_return(s);
 257 }
 258
 259 int ftrace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
 260 {
 261         va_list ap;
 262         int ret;
 263
 264         va_start(ap, fmt);
 265         ret = ftrace_output_raw(iter, name, fmt, ap);
 266         va_end(ap);
 267
 268         return ret;
 269 }
 270 EXPORT_SYMBOL_GPL(ftrace_output_call);
 271
 272 #ifdef CONFIG_KRETPROBES
 273 static inline const char *kretprobed(const char *name)
 274 {
 275         static const char tramp_name[] = "kretprobe_trampoline";
 276         int size = sizeof(tramp_name);
 277
 278         if (strncmp(tramp_name, name, size) == 0)
 279                 return "[unknown/kretprobe'd]";
 280         return name;
 281 }
 282 #else
 283 static inline const char *kretprobed(const char *name)
 284 {
 285         return name;
 286 }
 287 #endif /* CONFIG_KRETPROBES */
 288
 289 static void
 290 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
 291 {
 292 #ifdef CONFIG_KALLSYMS
 293         char str[KSYM_SYMBOL_LEN];
 294         const char *name;
 295
 296         kallsyms_lookup(address, NULL, NULL, NULL, str);
 297
 298         name = kretprobed(str);
 299
 300         trace_seq_printf(s, fmt, name);
 301 #endif
 302 }
 303
 304 static void
 305 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
 306                      unsigned long address)
 307 {
 308 #ifdef CONFIG_KALLSYMS
 309         char str[KSYM_SYMBOL_LEN];
 310         const char *name;
 311
 312         sprint_symbol(str, address);
 313         name = kretprobed(str);
 314
 315         trace_seq_printf(s, fmt, name);
 316 #endif
 317 }
 318
 319 #ifndef CONFIG_64BIT
 320 # define IP_FMT "%08lx"
 321 #else
 322 # define IP_FMT "%016lx"
 323 #endif
 324
 325 int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
 326                       unsigned long ip, unsigned long sym_flags)
 327 {
 328         struct file *file = NULL;
 329         unsigned long vmstart = 0;
 330         int ret = 1;
 331
 332         if (s->full)
 333                 return 0;
 334
 335         if (mm) {
 336                 const struct vm_area_struct *vma;
 337
 338                 down_read(&mm->mmap_sem);
 339                 vma = find_vma(mm, ip);
 340                 if (vma) {
 341                         file = vma->vm_file;
 342                         vmstart = vma->vm_start;
 343                 }
 344                 if (file) {
 345                         ret = trace_seq_path(s, &file->f_path);
 346                         if (ret)
 347                                 trace_seq_printf(s, "[+0x%lx]",
 348                                                  ip - vmstart);
 349                 }
 350                 up_read(&mm->mmap_sem);
 351         }
 352         if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
 353                 trace_seq_printf(s, " <" IP_FMT ">", ip);
 354         return !trace_seq_has_overflowed(s);
 355 }
 356
 357 int
 358 seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
 359                       unsigned long sym_flags)
 360 {
 361         struct mm_struct *mm = NULL;
 362         unsigned int i;
 363
 364         if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
 365                 struct task_struct *task;
 366                 /*
 367                  * we do the lookup on the thread group leader,
 368                  * since individual threads might have already quit!
 369                  */
 370                 rcu_read_lock();
 371                 task = find_task_by_vpid(entry->tgid);
 372                 if (task)
 373                         mm = get_task_mm(task);
 374                 rcu_read_unlock();
 375         }
 376
 377         for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
 378                 unsigned long ip = entry->caller[i];
 379
 380                 if (ip == ULONG_MAX || trace_seq_has_overflowed(s))
 381                         break;
 382
 383                 trace_seq_puts(s, " => ");
 384
 385                 if (!ip) {
 386                         trace_seq_puts(s, "??");
 387                         trace_seq_putc(s, '\n');
 388                         continue;
 389                 }
 390
 391                 seq_print_user_ip(s, mm, ip, sym_flags);
 392                 trace_seq_putc(s, '\n');
 393         }
 394
 395         if (mm)
 396                 mmput(mm);
 397
 398         return !trace_seq_has_overflowed(s);
 399 }
 400
 401 int
 402 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
 403 {
 404         if (!ip) {
 405                 trace_seq_putc(s, '0');
 406                 goto out;
 407         }
 408
 409         if (sym_flags & TRACE_ITER_SYM_OFFSET)
 410                 seq_print_sym_offset(s, "%s", ip);
 411         else
 412                 seq_print_sym_short(s, "%s", ip);
 413
 414         if (sym_flags & TRACE_ITER_SYM_ADDR)
 415                 trace_seq_printf(s, " <" IP_FMT ">", ip);
 416
 417  out:
 418         return !trace_seq_has_overflowed(s);
 419 }
 420
 421 /**
 422  * trace_print_lat_fmt - print the irq, preempt and lockdep fields
 423  * @s: trace seq struct to write to
 424  * @entry: The trace entry field from the ring buffer
 425  *
 426  * Prints the generic fields of irqs off, in hard or softirq, preempt
 427  * count.
 428  */
 429 int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 430 {
 431         char hardsoft_irq;
 432         char need_resched;
 433         char need_resched_lazy;
 434         char irqs_off;
 435         int hardirq;
 436         int softirq;
 437
 438         hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
 439         softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
 440
 441         irqs_off =
 442                 (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
 443                 (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
 444                 '.';
 445
 446         switch (entry->flags & (TRACE_FLAG_NEED_RESCHED |
 447                                 TRACE_FLAG_PREEMPT_RESCHED)) {
 448         case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_PREEMPT_RESCHED:
 449                 need_resched = 'N';
 450                 break;
 451         case TRACE_FLAG_NEED_RESCHED:
 452                 need_resched = 'n';
 453                 break;
 454         case TRACE_FLAG_PREEMPT_RESCHED:
 455                 need_resched = 'p';
 456                 break;
 457         default:
 458                 need_resched = '.';
 459                 break;
 460         }
 461         need_resched_lazy =
 462                 (entry->flags & TRACE_FLAG_NEED_RESCHED_LAZY) ? 'L' : '.';
 463
 464         hardsoft_irq =
 465                 (hardirq && softirq) ? 'H' :
 466                 hardirq ? 'h' :
 467                 softirq ? 's' :
 468                 '.';
 469
 470         trace_seq_printf(s, "%c%c%c%c",
 471                          irqs_off, need_resched, need_resched_lazy,
 472                          hardsoft_irq);
 473
 474         if (entry->preempt_count)
 475                 trace_seq_printf(s, "%x", entry->preempt_count);
 476         else
 477                 trace_seq_putc(s, '.');
 478
 479         if (entry->preempt_lazy_count)
 480                 trace_seq_printf(s, "%x", entry->preempt_lazy_count);
 481         else
 482                 trace_seq_putc(s, '.');
 483
 484         if (entry->migrate_disable)
 485                 trace_seq_printf(s, "%x", entry->migrate_disable);
 486         else
 487                 trace_seq_putc(s, '.');
 488
 489         return !trace_seq_has_overflowed(s);
 490 }
 491
 492 static int
 493 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
 494 {
 495         char comm[TASK_COMM_LEN];
 496
 497         trace_find_cmdline(entry->pid, comm);
 498
 499         trace_seq_printf(s, "%8.8s-%-5d %3d",
 500                          comm, entry->pid, cpu);
 501
 502         return trace_print_lat_fmt(s, entry);
 503 }
 504
 505 #undef MARK
 506 #define MARK(v, s) {.val = v, .sym = s}
 507 /* trace overhead mark */
 508 static const struct trace_mark {
 509         unsigned long long      val; /* unit: nsec */
 510         char                    sym;
 511 } mark[] = {
 512         MARK(1000000000ULL      , '$'), /* 1 sec */
 513         MARK(1000000ULL         , '#'), /* 1000 usecs */
 514         MARK(100000ULL          , '!'), /* 100 usecs */
 515         MARK(10000ULL           , '+'), /* 10 usecs */
 516 };
 517 #undef MARK
 518
 519 char trace_find_mark(unsigned long long d)
 520 {
 521         int i;
 522         int size = ARRAY_SIZE(mark);
 523
 524         for (i = 0; i < size; i++) {
 525                 if (d >= mark[i].val)
 526                         break;
 527         }
 528
 529         return (i == size) ? ' ' : mark[i].sym;
 530 }
 531
 532 static int
 533 lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
 534 {
 535         unsigned long verbose = trace_flags & TRACE_ITER_VERBOSE;
 536         unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
 537         unsigned long long abs_ts = iter->ts - iter->trace_buffer->time_start;
 538         unsigned long long rel_ts = next_ts - iter->ts;
 539         struct trace_seq *s = &iter->seq;
 540
 541         if (in_ns) {
 542                 abs_ts = ns2usecs(abs_ts);
 543                 rel_ts = ns2usecs(rel_ts);
 544         }
 545
 546         if (verbose && in_ns) {
 547                 unsigned long abs_usec = do_div(abs_ts, USEC_PER_MSEC);
 548                 unsigned long abs_msec = (unsigned long)abs_ts;
 549                 unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
 550                 unsigned long rel_msec = (unsigned long)rel_ts;
 551
 552                 trace_seq_printf(
 553                         s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
 554                         ns2usecs(iter->ts),
 555                         abs_msec, abs_usec,
 556                         rel_msec, rel_usec);
 557
 558         } else if (verbose && !in_ns) {
 559                 trace_seq_printf(
 560                         s, "[%016llx] %lld (+%lld): ",
 561                         iter->ts, abs_ts, rel_ts);
 562
 563         } else if (!verbose && in_ns) {
 564                 trace_seq_printf(
 565                         s, " %4lldus%c: ",
 566                         abs_ts,
 567                         trace_find_mark(rel_ts * NSEC_PER_USEC));
 568
 569         } else { /* !verbose && !in_ns */
 570                 trace_seq_printf(s, " %4lld: ", abs_ts);
 571         }
 572
 573         return !trace_seq_has_overflowed(s);
 574 }
 575
 576 int trace_print_context(struct trace_iterator *iter)
 577 {
 578         struct trace_seq *s = &iter->seq;
 579         struct trace_entry *entry = iter->ent;
 580         unsigned long long t;
 581         unsigned long secs, usec_rem;
 582         char comm[TASK_COMM_LEN];
 583
 584         trace_find_cmdline(entry->pid, comm);
 585
 586         trace_seq_printf(s, "%16s-%-5d [%03d] ",
 587                                comm, entry->pid, iter->cpu);
 588
 589         if (trace_flags & TRACE_ITER_IRQ_INFO)
 590                 trace_print_lat_fmt(s, entry);
 591
 592         if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
 593                 t = ns2usecs(iter->ts);
 594                 usec_rem = do_div(t, USEC_PER_SEC);
 595                 secs = (unsigned long)t;
 596                 trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
 597         } else
 598                 trace_seq_printf(s, " %12llu: ", iter->ts);
 599
 600         return !trace_seq_has_overflowed(s);
 601 }
 602
 603 int trace_print_lat_context(struct trace_iterator *iter)
 604 {
 605         u64 next_ts;
 606         /* trace_find_next_entry will reset ent_size */
 607         int ent_size = iter->ent_size;
 608         struct trace_seq *s = &iter->seq;
 609         struct trace_entry *entry = iter->ent,
 610                            *next_entry = trace_find_next_entry(iter, NULL,
 611                                                                &next_ts);
 612         unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
 613
 614         /* Restore the original ent_size */
 615         iter->ent_size = ent_size;
 616
 617         if (!next_entry)
 618                 next_ts = iter->ts;
 619
 620         if (verbose) {
 621                 char comm[TASK_COMM_LEN];
 622
 623                 trace_find_cmdline(entry->pid, comm);
 624
 625                 trace_seq_printf(
 626                         s, "%16s %5d %3d %d %08x %08lx ",
 627                         comm, entry->pid, iter->cpu, entry->flags,
 628                         entry->preempt_count, iter->idx);
 629         } else {
 630                 lat_print_generic(s, entry, iter->cpu);
 631         }
 632
 633         lat_print_timestamp(iter, next_ts);
 634
 635         return !trace_seq_has_overflowed(s);
 636 }
 637
 638 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
 639
 640 static int task_state_char(unsigned long state)
 641 {
 642         int bit = state ? __ffs(state) + 1 : 0;
 643
 644         return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
 645 }
 646
 647 /**
 648  * ftrace_find_event - find a registered event
 649  * @type: the type of event to look for
 650  *
 651  * Returns an event of type @type otherwise NULL
 652  * Called with trace_event_read_lock() held.
 653  */
 654 struct trace_event *ftrace_find_event(int type)
 655 {
 656         struct trace_event *event;
 657         unsigned key;
 658
 659         key = type & (EVENT_HASHSIZE - 1);
 660
 661         hlist_for_each_entry(event, &event_hash[key], node) {
 662                 if (event->type == type)
 663                         return event;
 664         }
 665
 666         return NULL;
 667 }
 668
 669 static LIST_HEAD(ftrace_event_list);
 670
 671 static int trace_search_list(struct list_head **list)
 672 {
 673         struct trace_event *e;
 674         int last = __TRACE_LAST_TYPE;
 675
 676         if (list_empty(&ftrace_event_list)) {
 677                 *list = &ftrace_event_list;
 678                 return last + 1;
 679         }
 680
 681         /*
 682          * We used up all possible max events,
 683          * lets see if somebody freed one.
 684          */
 685         list_for_each_entry(e, &ftrace_event_list, list) {
 686                 if (e->type != last + 1)
 687                         break;
 688                 last++;
 689         }
 690
 691         /* Did we used up all 65 thousand events??? */
 692         if ((last + 1) > FTRACE_MAX_EVENT)
 693                 return 0;
 694
 695         *list = &e->list;
 696         return last + 1;
 697 }
 698
 699 void trace_event_read_lock(void)
 700 {
 701         down_read(&trace_event_sem);
 702 }
 703
 704 void trace_event_read_unlock(void)
 705 {
 706         up_read(&trace_event_sem);
 707 }
 708
 709 /**
 710  * register_ftrace_event - register output for an event type
 711  * @event: the event type to register
 712  *
 713  * Event types are stored in a hash and this hash is used to
 714  * find a way to print an event. If the @event->type is set
 715  * then it will use that type, otherwise it will assign a
 716  * type to use.
 717  *
 718  * If you assign your own type, please make sure it is added
 719  * to the trace_type enum in trace.h, to avoid collisions
 720  * with the dynamic types.
 721  *
 722  * Returns the event type number or zero on error.
 723  */
 724 int register_ftrace_event(struct trace_event *event)
 725 {
 726         unsigned key;
 727         int ret = 0;
 728
 729         down_write(&trace_event_sem);
 730
 731         if (WARN_ON(!event))
 732                 goto out;
 733
 734         if (WARN_ON(!event->funcs))
 735                 goto out;
 736
 737         INIT_LIST_HEAD(&event->list);
 738
 739         if (!event->type) {
 740                 struct list_head *list = NULL;
 741
 742                 if (next_event_type > FTRACE_MAX_EVENT) {
 743
 744                         event->type = trace_search_list(&list);
 745                         if (!event->type)
 746                                 goto out;
 747
 748                 } else {
 749
 750                         event->type = next_event_type++;
 751                         list = &ftrace_event_list;
 752                 }
 753
 754                 if (WARN_ON(ftrace_find_event(event->type)))
 755                         goto out;
 756
 757                 list_add_tail(&event->list, list);
 758
 759         } else if (event->type > __TRACE_LAST_TYPE) {
 760                 printk(KERN_WARNING "Need to add type to trace.h\n");
 761                 WARN_ON(1);
 762                 goto out;
 763         } else {
 764                 /* Is this event already used */
 765                 if (ftrace_find_event(event->type))
 766                         goto out;
 767         }
 768
 769         if (event->funcs->trace == NULL)
 770                 event->funcs->trace = trace_nop_print;
 771         if (event->funcs->raw == NULL)
 772                 event->funcs->raw = trace_nop_print;
 773         if (event->funcs->hex == NULL)
 774                 event->funcs->hex = trace_nop_print;
 775         if (event->funcs->binary == NULL)
 776                 event->funcs->binary = trace_nop_print;
 777
 778         key = event->type & (EVENT_HASHSIZE - 1);
 779
 780         hlist_add_head(&event->node, &event_hash[key]);
 781
 782         ret = event->type;
 783  out:
 784         up_write(&trace_event_sem);
 785
 786         return ret;
 787 }
 788 EXPORT_SYMBOL_GPL(register_ftrace_event);
 789
 790 /*
 791  * Used by module code with the trace_event_sem held for write.
 792  */
 793 int __unregister_ftrace_event(struct trace_event *event)
 794 {
 795         hlist_del(&event->node);
 796         list_del(&event->list);
 797         return 0;
 798 }
 799
 800 /**
 801  * unregister_ftrace_event - remove a no longer used event
 802  * @event: the event to remove
 803  */
 804 int unregister_ftrace_event(struct trace_event *event)
 805 {
 806         down_write(&trace_event_sem);
 807         __unregister_ftrace_event(event);
 808         up_write(&trace_event_sem);
 809
 810         return 0;
 811 }
 812 EXPORT_SYMBOL_GPL(unregister_ftrace_event);
 813
 814 /*
 815  * Standard events
 816  */
 817
 818 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
 819                                   struct trace_event *event)
 820 {
 821         trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type);
 822
 823         return trace_handle_return(&iter->seq);
 824 }
 825
 826 /* TRACE_FN */
 827 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
 828                                         struct trace_event *event)
 829 {
 830         struct ftrace_entry *field;
 831         struct trace_seq *s = &iter->seq;
 832
 833         trace_assign_type(field, iter->ent);
 834
 835         seq_print_ip_sym(s, field->ip, flags);
 836
 837         if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
 838                 trace_seq_puts(s, " <-");
 839                 seq_print_ip_sym(s, field->parent_ip, flags);
 840         }
 841
 842         trace_seq_putc(s, '\n');
 843
 844         return trace_handle_return(s);
 845 }
 846
 847 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
 848                                       struct trace_event *event)
 849 {
 850         struct ftrace_entry *field;
 851
 852         trace_assign_type(field, iter->ent);
 853
 854         trace_seq_printf(&iter->seq, "%lx %lx\n",
 855                          field->ip,
 856                          field->parent_ip);
 857
 858         return trace_handle_return(&iter->seq);
 859 }
 860
 861 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
 862                                       struct trace_event *event)
 863 {
 864         struct ftrace_entry *field;
 865         struct trace_seq *s = &iter->seq;
 866
 867         trace_assign_type(field, iter->ent);
 868
 869         SEQ_PUT_HEX_FIELD(s, field->ip);
 870         SEQ_PUT_HEX_FIELD(s, field->parent_ip);
 871
 872         return trace_handle_return(s);
 873 }
 874
 875 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
 876                                       struct trace_event *event)
 877 {
 878         struct ftrace_entry *field;
 879         struct trace_seq *s = &iter->seq;
 880
 881         trace_assign_type(field, iter->ent);
 882
 883         SEQ_PUT_FIELD(s, field->ip);
 884         SEQ_PUT_FIELD(s, field->parent_ip);
 885
 886         return trace_handle_return(s);
 887 }
 888
 889 static struct trace_event_functions trace_fn_funcs = {
 890         .trace          = trace_fn_trace,
 891         .raw            = trace_fn_raw,
 892         .hex            = trace_fn_hex,
 893         .binary         = trace_fn_bin,
 894 };
 895
 896 static struct trace_event trace_fn_event = {
 897         .type           = TRACE_FN,
 898         .funcs          = &trace_fn_funcs,
 899 };
 900
 901 /* TRACE_CTX an TRACE_WAKE */
 902 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
 903                                              char *delim)
 904 {
 905         struct ctx_switch_entry *field;
 906         char comm[TASK_COMM_LEN];
 907         int S, T;
 908
 909
 910         trace_assign_type(field, iter->ent);
 911
 912         T = task_state_char(field->next_state);
 913         S = task_state_char(field->prev_state);
 914         trace_find_cmdline(field->next_pid, comm);
 915         trace_seq_printf(&iter->seq,
 916                          " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
 917                          field->prev_pid,
 918                          field->prev_prio,
 919                          S, delim,
 920                          field->next_cpu,
 921                          field->next_pid,
 922                          field->next_prio,
 923                          T, comm);
 924
 925         return trace_handle_return(&iter->seq);
 926 }
 927
 928 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
 929                                          struct trace_event *event)
 930 {
 931         return trace_ctxwake_print(iter, "==>");
 932 }
 933
 934 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
 935                                           int flags, struct trace_event *event)
 936 {
 937         return trace_ctxwake_print(iter, "  +");
 938 }
 939
 940 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
 941 {
 942         struct ctx_switch_entry *field;
 943         int T;
 944
 945         trace_assign_type(field, iter->ent);
 946
 947         if (!S)
 948                 S = task_state_char(field->prev_state);
 949         T = task_state_char(field->next_state);
 950         trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
 951                          field->prev_pid,
 952                          field->prev_prio,
 953                          S,
 954                          field->next_cpu,
 955                          field->next_pid,
 956                          field->next_prio,
 957                          T);
 958
 959         return trace_handle_return(&iter->seq);
 960 }
 961
 962 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
 963                                        struct trace_event *event)
 964 {
 965         return trace_ctxwake_raw(iter, 0);
 966 }
 967
 968 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
 969                                         struct trace_event *event)
 970 {
 971         return trace_ctxwake_raw(iter, '+');
 972 }
 973
 974
 975 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
 976 {
 977         struct ctx_switch_entry *field;
 978         struct trace_seq *s = &iter->seq;
 979         int T;
 980
 981         trace_assign_type(field, iter->ent);
 982
 983         if (!S)
 984                 S = task_state_char(field->prev_state);
 985         T = task_state_char(field->next_state);
 986
 987         SEQ_PUT_HEX_FIELD(s, field->prev_pid);
 988         SEQ_PUT_HEX_FIELD(s, field->prev_prio);
 989         SEQ_PUT_HEX_FIELD(s, S);
 990         SEQ_PUT_HEX_FIELD(s, field->next_cpu);
 991         SEQ_PUT_HEX_FIELD(s, field->next_pid);
 992         SEQ_PUT_HEX_FIELD(s, field->next_prio);
 993         SEQ_PUT_HEX_FIELD(s, T);
 994
 995         return trace_handle_return(s);
 996 }
 997
 998 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
 999                                        struct trace_event *event)
1000 {
1001         return trace_ctxwake_hex(iter, 0);
1002 }
1003
1004 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
1005                                         struct trace_event *event)
1006 {
1007         return trace_ctxwake_hex(iter, '+');
1008 }
1009
1010 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
1011                                            int flags, struct trace_event *event)
1012 {
1013         struct ctx_switch_entry *field;
1014         struct trace_seq *s = &iter->seq;
1015
1016         trace_assign_type(field, iter->ent);
1017
1018         SEQ_PUT_FIELD(s, field->prev_pid);
1019         SEQ_PUT_FIELD(s, field->prev_prio);
1020         SEQ_PUT_FIELD(s, field->prev_state);
1021         SEQ_PUT_FIELD(s, field->next_cpu);
1022         SEQ_PUT_FIELD(s, field->next_pid);
1023         SEQ_PUT_FIELD(s, field->next_prio);
1024         SEQ_PUT_FIELD(s, field->next_state);
1025
1026         return trace_handle_return(s);
1027 }
1028
1029 static struct trace_event_functions trace_ctx_funcs = {
1030         .trace          = trace_ctx_print,
1031         .raw            = trace_ctx_raw,
1032         .hex            = trace_ctx_hex,
1033         .binary         = trace_ctxwake_bin,
1034 };
1035
1036 static struct trace_event trace_ctx_event = {
1037         .type           = TRACE_CTX,
1038         .funcs          = &trace_ctx_funcs,
1039 };
1040
1041 static struct trace_event_functions trace_wake_funcs = {
1042         .trace          = trace_wake_print,
1043         .raw            = trace_wake_raw,
1044         .hex            = trace_wake_hex,
1045         .binary         = trace_ctxwake_bin,
1046 };
1047
1048 static struct trace_event trace_wake_event = {
1049         .type           = TRACE_WAKE,
1050         .funcs          = &trace_wake_funcs,
1051 };
1052
1053 /* TRACE_STACK */
1054
1055 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1056                                            int flags, struct trace_event *event)
1057 {
1058         struct stack_entry *field;
1059         struct trace_seq *s = &iter->seq;
1060         unsigned long *p;
1061         unsigned long *end;
1062
1063         trace_assign_type(field, iter->ent);
1064         end = (unsigned long *)((long)iter->ent + iter->ent_size);
1065
1066         trace_seq_puts(s, "<stack trace>\n");
1067
1068         for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
1069
1070                 if (trace_seq_has_overflowed(s))
1071                         break;
1072
1073                 trace_seq_puts(s, " => ");
1074                 seq_print_ip_sym(s, *p, flags);
1075                 trace_seq_putc(s, '\n');
1076         }
1077
1078         return trace_handle_return(s);
1079 }
1080
1081 static struct trace_event_functions trace_stack_funcs = {
1082         .trace          = trace_stack_print,
1083 };
1084
1085 static struct trace_event trace_stack_event = {
1086         .type           = TRACE_STACK,
1087         .funcs          = &trace_stack_funcs,
1088 };
1089
1090 /* TRACE_USER_STACK */
1091 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1092                                                 int flags, struct trace_event *event)
1093 {
1094         struct userstack_entry *field;
1095         struct trace_seq *s = &iter->seq;
1096
1097         trace_assign_type(field, iter->ent);
1098
1099         trace_seq_puts(s, "<user stack trace>\n");
1100         seq_print_userip_objs(field, s, flags);
1101
1102         return trace_handle_return(s);
1103 }
1104
1105 static struct trace_event_functions trace_user_stack_funcs = {
1106         .trace          = trace_user_stack_print,
1107 };
1108
1109 static struct trace_event trace_user_stack_event = {
1110         .type           = TRACE_USER_STACK,
1111         .funcs          = &trace_user_stack_funcs,
1112 };
1113
1114 /* TRACE_BPUTS */
1115 static enum print_line_t
1116 trace_bputs_print(struct trace_iterator *iter, int flags,
1117                    struct trace_event *event)
1118 {
1119         struct trace_entry *entry = iter->ent;
1120         struct trace_seq *s = &iter->seq;
1121         struct bputs_entry *field;
1122
1123         trace_assign_type(field, entry);
1124
1125         seq_print_ip_sym(s, field->ip, flags);
1126         trace_seq_puts(s, ": ");
1127         trace_seq_puts(s, field->str);
1128
1129         return trace_handle_return(s);
1130 }
1131
1132
1133 static enum print_line_t
1134 trace_bputs_raw(struct trace_iterator *iter, int flags,
1135                 struct trace_event *event)
1136 {
1137         struct bputs_entry *field;
1138         struct trace_seq *s = &iter->seq;
1139
1140         trace_assign_type(field, iter->ent);
1141
1142         trace_seq_printf(s, ": %lx : ", field->ip);
1143         trace_seq_puts(s, field->str);
1144
1145         return trace_handle_return(s);
1146 }
1147
1148 static struct trace_event_functions trace_bputs_funcs = {
1149         .trace          = trace_bputs_print,
1150         .raw            = trace_bputs_raw,
1151 };
1152
1153 static struct trace_event trace_bputs_event = {
1154         .type           = TRACE_BPUTS,
1155         .funcs          = &trace_bputs_funcs,
1156 };
1157
1158 /* TRACE_BPRINT */
1159 static enum print_line_t
1160 trace_bprint_print(struct trace_iterator *iter, int flags,
1161                    struct trace_event *event)
1162 {
1163         struct trace_entry *entry = iter->ent;
1164         struct trace_seq *s = &iter->seq;
1165         struct bprint_entry *field;
1166
1167         trace_assign_type(field, entry);
1168
1169         seq_print_ip_sym(s, field->ip, flags);
1170         trace_seq_puts(s, ": ");
1171         trace_seq_bprintf(s, field->fmt, field->buf);
1172
1173         return trace_handle_return(s);
1174 }
1175
1176
1177 static enum print_line_t
1178 trace_bprint_raw(struct trace_iterator *iter, int flags,
1179                  struct trace_event *event)
1180 {
1181         struct bprint_entry *field;
1182         struct trace_seq *s = &iter->seq;
1183
1184         trace_assign_type(field, iter->ent);
1185
1186         trace_seq_printf(s, ": %lx : ", field->ip);
1187         trace_seq_bprintf(s, field->fmt, field->buf);
1188
1189         return trace_handle_return(s);
1190 }
1191
1192 static struct trace_event_functions trace_bprint_funcs = {
1193         .trace          = trace_bprint_print,
1194         .raw            = trace_bprint_raw,
1195 };
1196
1197 static struct trace_event trace_bprint_event = {
1198         .type           = TRACE_BPRINT,
1199         .funcs          = &trace_bprint_funcs,
1200 };
1201
1202 /* TRACE_PRINT */
1203 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1204                                            int flags, struct trace_event *event)
1205 {
1206         struct print_entry *field;
1207         struct trace_seq *s = &iter->seq;
1208
1209         trace_assign_type(field, iter->ent);
1210
1211         seq_print_ip_sym(s, field->ip, flags);
1212         trace_seq_printf(s, ": %s", field->buf);
1213
1214         return trace_handle_return(s);
1215 }
1216
1217 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1218                                          struct trace_event *event)
1219 {
1220         struct print_entry *field;
1221
1222         trace_assign_type(field, iter->ent);
1223
1224         trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf);
1225
1226         return trace_handle_return(&iter->seq);
1227 }
1228
1229 static struct trace_event_functions trace_print_funcs = {
1230         .trace          = trace_print_print,
1231         .raw            = trace_print_raw,
1232 };
1233
1234 static struct trace_event trace_print_event = {
1235         .type           = TRACE_PRINT,
1236         .funcs          = &trace_print_funcs,
1237 };
1238
1239
1240 static struct trace_event *events[] __initdata = {
1241         &trace_fn_event,
1242         &trace_ctx_event,
1243         &trace_wake_event,
1244         &trace_stack_event,
1245         &trace_user_stack_event,
1246         &trace_bputs_event,
1247         &trace_bprint_event,
1248         &trace_print_event,
1249         NULL
1250 };
1251
1252 __init static int init_events(void)
1253 {
1254         struct trace_event *event;
1255         int i, ret;
1256
1257         for (i = 0; events[i]; i++) {
1258                 event = events[i];
1259
1260                 ret = register_ftrace_event(event);
1261                 if (!ret) {
1262                         printk(KERN_WARNING "event %d failed to register\n",
1263                                event->type);
1264                         WARN_ON_ONCE(1);
1265                 }
1266         }
1267
1268         return 0;
1269 }
1270 early_initcall(init_events);