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_mutex);
  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 int trace_print_seq(struct seq_file *m, struct trace_seq *s)
  24 {
  25         int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
  26         int ret;
  27
  28         ret = seq_write(m, s->buffer, len);
  29
  30         /*
  31          * Only reset this buffer if we successfully wrote to the
  32          * seq_file buffer.
  33          */
  34         if (!ret)
  35                 trace_seq_init(s);
  36
  37         return ret;
  38 }
  39
  40 enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
  41 {
  42         struct trace_seq *s = &iter->seq;
  43         struct trace_entry *entry = iter->ent;
  44         struct bprint_entry *field;
  45         int ret;
  46
  47         trace_assign_type(field, entry);
  48
  49         ret = trace_seq_bprintf(s, field->fmt, field->buf);
  50         if (!ret)
  51                 return TRACE_TYPE_PARTIAL_LINE;
  52
  53         return TRACE_TYPE_HANDLED;
  54 }
  55
  56 enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
  57 {
  58         struct trace_seq *s = &iter->seq;
  59         struct trace_entry *entry = iter->ent;
  60         struct print_entry *field;
  61         int ret;
  62
  63         trace_assign_type(field, entry);
  64
  65         ret = trace_seq_printf(s, "%s", field->buf);
  66         if (!ret)
  67                 return TRACE_TYPE_PARTIAL_LINE;
  68
  69         return TRACE_TYPE_HANDLED;
  70 }
  71
  72 /**
  73  * trace_seq_printf - sequence printing of trace information
  74  * @s: trace sequence descriptor
  75  * @fmt: printf format string
  76  *
  77  * It returns 0 if the trace oversizes the buffer's free
  78  * space, 1 otherwise.
  79  *
  80  * The tracer may use either sequence operations or its own
  81  * copy to user routines. To simplify formating of a trace
  82  * trace_seq_printf is used to store strings into a special
  83  * buffer (@s). Then the output may be either used by
  84  * the sequencer or pulled into another buffer.
  85  */
  86 int
  87 trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
  88 {
  89         int len = (PAGE_SIZE - 1) - s->len;
  90         va_list ap;
  91         int ret;
  92
  93         if (s->full || !len)
  94                 return 0;
  95
  96         va_start(ap, fmt);
  97         ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
  98         va_end(ap);
  99
 100         /* If we can't write it all, don't bother writing anything */
 101         if (ret >= len) {
 102                 s->full = 1;
 103                 return 0;
 104         }
 105
 106         s->len += ret;
 107
 108         return 1;
 109 }
 110 EXPORT_SYMBOL_GPL(trace_seq_printf);
 111
 112 /**
 113  * trace_seq_vprintf - sequence printing of trace information
 114  * @s: trace sequence descriptor
 115  * @fmt: printf format string
 116  *
 117  * The tracer may use either sequence operations or its own
 118  * copy to user routines. To simplify formating of a trace
 119  * trace_seq_printf is used to store strings into a special
 120  * buffer (@s). Then the output may be either used by
 121  * the sequencer or pulled into another buffer.
 122  */
 123 int
 124 trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
 125 {
 126         int len = (PAGE_SIZE - 1) - s->len;
 127         int ret;
 128
 129         if (s->full || !len)
 130                 return 0;
 131
 132         ret = vsnprintf(s->buffer + s->len, len, fmt, args);
 133
 134         /* If we can't write it all, don't bother writing anything */
 135         if (ret >= len) {
 136                 s->full = 1;
 137                 return 0;
 138         }
 139
 140         s->len += ret;
 141
 142         return len;
 143 }
 144 EXPORT_SYMBOL_GPL(trace_seq_vprintf);
 145
 146 int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 147 {
 148         int len = (PAGE_SIZE - 1) - s->len;
 149         int ret;
 150
 151         if (s->full || !len)
 152                 return 0;
 153
 154         ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
 155
 156         /* If we can't write it all, don't bother writing anything */
 157         if (ret >= len) {
 158                 s->full = 1;
 159                 return 0;
 160         }
 161
 162         s->len += ret;
 163
 164         return len;
 165 }
 166
 167 /**
 168  * trace_seq_puts - trace sequence printing of simple string
 169  * @s: trace sequence descriptor
 170  * @str: simple string to record
 171  *
 172  * The tracer may use either the sequence operations or its own
 173  * copy to user routines. This function records a simple string
 174  * into a special buffer (@s) for later retrieval by a sequencer
 175  * or other mechanism.
 176  */
 177 int trace_seq_puts(struct trace_seq *s, const char *str)
 178 {
 179         int len = strlen(str);
 180
 181         if (s->full)
 182                 return 0;
 183
 184         if (len > ((PAGE_SIZE - 1) - s->len)) {
 185                 s->full = 1;
 186                 return 0;
 187         }
 188
 189         memcpy(s->buffer + s->len, str, len);
 190         s->len += len;
 191
 192         return len;
 193 }
 194
 195 int trace_seq_putc(struct trace_seq *s, unsigned char c)
 196 {
 197         if (s->full)
 198                 return 0;
 199
 200         if (s->len >= (PAGE_SIZE - 1)) {
 201                 s->full = 1;
 202                 return 0;
 203         }
 204
 205         s->buffer[s->len++] = c;
 206
 207         return 1;
 208 }
 209 EXPORT_SYMBOL(trace_seq_putc);
 210
 211 int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len)
 212 {
 213         if (s->full)
 214                 return 0;
 215
 216         if (len > ((PAGE_SIZE - 1) - s->len)) {
 217                 s->full = 1;
 218                 return 0;
 219         }
 220
 221         memcpy(s->buffer + s->len, mem, len);
 222         s->len += len;
 223
 224         return len;
 225 }
 226
 227 int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len)
 228 {
 229         unsigned char hex[HEX_CHARS];
 230         const unsigned char *data = mem;
 231         int i, j;
 232
 233         if (s->full)
 234                 return 0;
 235
 236 #ifdef __BIG_ENDIAN
 237         for (i = 0, j = 0; i < len; i++) {
 238 #else
 239         for (i = len-1, j = 0; i >= 0; i--) {
 240 #endif
 241                 hex[j++] = hex_asc_hi(data[i]);
 242                 hex[j++] = hex_asc_lo(data[i]);
 243         }
 244         hex[j++] = ' ';
 245
 246         return trace_seq_putmem(s, hex, j);
 247 }
 248
 249 void *trace_seq_reserve(struct trace_seq *s, size_t len)
 250 {
 251         void *ret;
 252
 253         if (s->full)
 254                 return NULL;
 255
 256         if (len > ((PAGE_SIZE - 1) - s->len)) {
 257                 s->full = 1;
 258                 return NULL;
 259         }
 260
 261         ret = s->buffer + s->len;
 262         s->len += len;
 263
 264         return ret;
 265 }
 266
 267 int trace_seq_path(struct trace_seq *s, struct path *path)
 268 {
 269         unsigned char *p;
 270
 271         if (s->full)
 272                 return 0;
 273
 274         if (s->len >= (PAGE_SIZE - 1)) {
 275                 s->full = 1;
 276                 return 0;
 277         }
 278
 279         p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
 280         if (!IS_ERR(p)) {
 281                 p = mangle_path(s->buffer + s->len, p, "\n");
 282                 if (p) {
 283                         s->len = p - s->buffer;
 284                         return 1;
 285                 }
 286         } else {
 287                 s->buffer[s->len++] = '?';
 288                 return 1;
 289         }
 290
 291         s->full = 1;
 292         return 0;
 293 }
 294
 295 const char *
 296 ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
 297                        unsigned long flags,
 298                        const struct trace_print_flags *flag_array)
 299 {
 300         unsigned long mask;
 301         const char *str;
 302         const char *ret = p->buffer + p->len;
 303         int i;
 304
 305         for (i = 0;  flag_array[i].name && flags; i++) {
 306
 307                 mask = flag_array[i].mask;
 308                 if ((flags & mask) != mask)
 309                         continue;
 310
 311                 str = flag_array[i].name;
 312                 flags &= ~mask;
 313                 if (p->len && delim)
 314                         trace_seq_puts(p, delim);
 315                 trace_seq_puts(p, str);
 316         }
 317
 318         /* check for left over flags */
 319         if (flags) {
 320                 if (p->len && delim)
 321                         trace_seq_puts(p, delim);
 322                 trace_seq_printf(p, "0x%lx", flags);
 323         }
 324
 325         trace_seq_putc(p, 0);
 326
 327         return ret;
 328 }
 329 EXPORT_SYMBOL(ftrace_print_flags_seq);
 330
 331 const char *
 332 ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
 333                          const struct trace_print_flags *symbol_array)
 334 {
 335         int i;
 336         const char *ret = p->buffer + p->len;
 337
 338         for (i = 0;  symbol_array[i].name; i++) {
 339
 340                 if (val != symbol_array[i].mask)
 341                         continue;
 342
 343                 trace_seq_puts(p, symbol_array[i].name);
 344                 break;
 345         }
 346
 347         if (!p->len)
 348                 trace_seq_printf(p, "0x%lx", val);
 349
 350         trace_seq_putc(p, 0);
 351
 352         return ret;
 353 }
 354 EXPORT_SYMBOL(ftrace_print_symbols_seq);
 355
 356 #if BITS_PER_LONG == 32
 357 const char *
 358 ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
 359                          const struct trace_print_flags_u64 *symbol_array)
 360 {
 361         int i;
 362         const char *ret = p->buffer + p->len;
 363
 364         for (i = 0;  symbol_array[i].name; i++) {
 365
 366                 if (val != symbol_array[i].mask)
 367                         continue;
 368
 369                 trace_seq_puts(p, symbol_array[i].name);
 370                 break;
 371         }
 372
 373         if (!p->len)
 374                 trace_seq_printf(p, "0x%llx", val);
 375
 376         trace_seq_putc(p, 0);
 377
 378         return ret;
 379 }
 380 EXPORT_SYMBOL(ftrace_print_symbols_seq_u64);
 381 #endif
 382
 383 const char *
 384 ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
 385 {
 386         int i;
 387         const char *ret = p->buffer + p->len;
 388
 389         for (i = 0; i < buf_len; i++)
 390                 trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
 391
 392         trace_seq_putc(p, 0);
 393
 394         return ret;
 395 }
 396 EXPORT_SYMBOL(ftrace_print_hex_seq);
 397
 398 #ifdef CONFIG_KRETPROBES
 399 static inline const char *kretprobed(const char *name)
 400 {
 401         static const char tramp_name[] = "kretprobe_trampoline";
 402         int size = sizeof(tramp_name);
 403
 404         if (strncmp(tramp_name, name, size) == 0)
 405                 return "[unknown/kretprobe'd]";
 406         return name;
 407 }
 408 #else
 409 static inline const char *kretprobed(const char *name)
 410 {
 411         return name;
 412 }
 413 #endif /* CONFIG_KRETPROBES */
 414
 415 static int
 416 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
 417 {
 418 #ifdef CONFIG_KALLSYMS
 419         char str[KSYM_SYMBOL_LEN];
 420         const char *name;
 421
 422         kallsyms_lookup(address, NULL, NULL, NULL, str);
 423
 424         name = kretprobed(str);
 425
 426         return trace_seq_printf(s, fmt, name);
 427 #endif
 428         return 1;
 429 }
 430
 431 static int
 432 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
 433                      unsigned long address)
 434 {
 435 #ifdef CONFIG_KALLSYMS
 436         char str[KSYM_SYMBOL_LEN];
 437         const char *name;
 438
 439         sprint_symbol(str, address);
 440         name = kretprobed(str);
 441
 442         return trace_seq_printf(s, fmt, name);
 443 #endif
 444         return 1;
 445 }
 446
 447 #ifndef CONFIG_64BIT
 448 # define IP_FMT "%08lx"
 449 #else
 450 # define IP_FMT "%016lx"
 451 #endif
 452
 453 int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
 454                       unsigned long ip, unsigned long sym_flags)
 455 {
 456         struct file *file = NULL;
 457         unsigned long vmstart = 0;
 458         int ret = 1;
 459
 460         if (s->full)
 461                 return 0;
 462
 463         if (mm) {
 464                 const struct vm_area_struct *vma;
 465
 466                 down_read(&mm->mmap_sem);
 467                 vma = find_vma(mm, ip);
 468                 if (vma) {
 469                         file = vma->vm_file;
 470                         vmstart = vma->vm_start;
 471                 }
 472                 if (file) {
 473                         ret = trace_seq_path(s, &file->f_path);
 474                         if (ret)
 475                                 ret = trace_seq_printf(s, "[+0x%lx]",
 476                                                        ip - vmstart);
 477                 }
 478                 up_read(&mm->mmap_sem);
 479         }
 480         if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
 481                 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
 482         return ret;
 483 }
 484
 485 int
 486 seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
 487                       unsigned long sym_flags)
 488 {
 489         struct mm_struct *mm = NULL;
 490         int ret = 1;
 491         unsigned int i;
 492
 493         if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
 494                 struct task_struct *task;
 495                 /*
 496                  * we do the lookup on the thread group leader,
 497                  * since individual threads might have already quit!
 498                  */
 499                 rcu_read_lock();
 500                 task = find_task_by_vpid(entry->tgid);
 501                 if (task)
 502                         mm = get_task_mm(task);
 503                 rcu_read_unlock();
 504         }
 505
 506         for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
 507                 unsigned long ip = entry->caller[i];
 508
 509                 if (ip == ULONG_MAX || !ret)
 510                         break;
 511                 if (ret)
 512                         ret = trace_seq_puts(s, " => ");
 513                 if (!ip) {
 514                         if (ret)
 515                                 ret = trace_seq_puts(s, "??");
 516                         if (ret)
 517                                 ret = trace_seq_puts(s, "\n");
 518                         continue;
 519                 }
 520                 if (!ret)
 521                         break;
 522                 if (ret)
 523                         ret = seq_print_user_ip(s, mm, ip, sym_flags);
 524                 ret = trace_seq_puts(s, "\n");
 525         }
 526
 527         if (mm)
 528                 mmput(mm);
 529         return ret;
 530 }
 531
 532 int
 533 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
 534 {
 535         int ret;
 536
 537         if (!ip)
 538                 return trace_seq_printf(s, "0");
 539
 540         if (sym_flags & TRACE_ITER_SYM_OFFSET)
 541                 ret = seq_print_sym_offset(s, "%s", ip);
 542         else
 543                 ret = seq_print_sym_short(s, "%s", ip);
 544
 545         if (!ret)
 546                 return 0;
 547
 548         if (sym_flags & TRACE_ITER_SYM_ADDR)
 549                 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
 550         return ret;
 551 }
 552
 553 /**
 554  * trace_print_lat_fmt - print the irq, preempt and lockdep fields
 555  * @s: trace seq struct to write to
 556  * @entry: The trace entry field from the ring buffer
 557  *
 558  * Prints the generic fields of irqs off, in hard or softirq, preempt
 559  * count.
 560  */
 561 int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 562 {
 563         char hardsoft_irq;
 564         char need_resched;
 565         char irqs_off;
 566         int hardirq;
 567         int softirq;
 568         int ret;
 569
 570         hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
 571         softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
 572
 573         irqs_off =
 574                 (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
 575                 (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
 576                 '.';
 577         need_resched =
 578                 (entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.';
 579         hardsoft_irq =
 580                 (hardirq && softirq) ? 'H' :
 581                 hardirq ? 'h' :
 582                 softirq ? 's' :
 583                 '.';
 584
 585         if (!trace_seq_printf(s, "%c%c%c",
 586                               irqs_off, need_resched, hardsoft_irq))
 587                 return 0;
 588
 589         if (entry->preempt_count)
 590                 ret = trace_seq_printf(s, "%x", entry->preempt_count);
 591         else
 592                 ret = trace_seq_putc(s, '.');
 593
 594         return ret;
 595 }
 596
 597 static int
 598 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
 599 {
 600         char comm[TASK_COMM_LEN];
 601
 602         trace_find_cmdline(entry->pid, comm);
 603
 604         if (!trace_seq_printf(s, "%8.8s-%-5d %3d",
 605                               comm, entry->pid, cpu))
 606                 return 0;
 607
 608         return trace_print_lat_fmt(s, entry);
 609 }
 610
 611 static unsigned long preempt_mark_thresh = 100;
 612
 613 static int
 614 lat_print_timestamp(struct trace_seq *s, u64 abs_usecs,
 615                     unsigned long rel_usecs)
 616 {
 617         return trace_seq_printf(s, " %4lldus%c: ", abs_usecs,
 618                                 rel_usecs > preempt_mark_thresh ? '!' :
 619                                   rel_usecs > 1 ? '+' : ' ');
 620 }
 621
 622 int trace_print_context(struct trace_iterator *iter)
 623 {
 624         struct trace_seq *s = &iter->seq;
 625         struct trace_entry *entry = iter->ent;
 626         unsigned long long t = ns2usecs(iter->ts);
 627         unsigned long usec_rem = do_div(t, USEC_PER_SEC);
 628         unsigned long secs = (unsigned long)t;
 629         char comm[TASK_COMM_LEN];
 630
 631         trace_find_cmdline(entry->pid, comm);
 632
 633         return trace_seq_printf(s, "%16s-%-5d [%03d] %5lu.%06lu: ",
 634                                 comm, entry->pid, iter->cpu, secs, usec_rem);
 635 }
 636
 637 int trace_print_lat_context(struct trace_iterator *iter)
 638 {
 639         u64 next_ts;
 640         int ret;
 641         struct trace_seq *s = &iter->seq;
 642         struct trace_entry *entry = iter->ent,
 643                            *next_entry = trace_find_next_entry(iter, NULL,
 644                                                                &next_ts);
 645         unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
 646         unsigned long abs_usecs = ns2usecs(iter->ts - iter->tr->time_start);
 647         unsigned long rel_usecs;
 648
 649         if (!next_entry)
 650                 next_ts = iter->ts;
 651         rel_usecs = ns2usecs(next_ts - iter->ts);
 652
 653         if (verbose) {
 654                 char comm[TASK_COMM_LEN];
 655
 656                 trace_find_cmdline(entry->pid, comm);
 657
 658                 ret = trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08llx]"
 659                                        " %ld.%03ldms (+%ld.%03ldms): ", comm,
 660                                        entry->pid, iter->cpu, entry->flags,
 661                                        entry->preempt_count, iter->idx,
 662                                        ns2usecs(iter->ts),
 663                                        abs_usecs / USEC_PER_MSEC,
 664                                        abs_usecs % USEC_PER_MSEC,
 665                                        rel_usecs / USEC_PER_MSEC,
 666                                        rel_usecs % USEC_PER_MSEC);
 667         } else {
 668                 ret = lat_print_generic(s, entry, iter->cpu);
 669                 if (ret)
 670                         ret = lat_print_timestamp(s, abs_usecs, rel_usecs);
 671         }
 672
 673         return ret;
 674 }
 675
 676 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
 677
 678 static int task_state_char(unsigned long state)
 679 {
 680         int bit = state ? __ffs(state) + 1 : 0;
 681
 682         return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
 683 }
 684
 685 /**
 686  * ftrace_find_event - find a registered event
 687  * @type: the type of event to look for
 688  *
 689  * Returns an event of type @type otherwise NULL
 690  * Called with trace_event_read_lock() held.
 691  */
 692 struct trace_event *ftrace_find_event(int type)
 693 {
 694         struct trace_event *event;
 695         struct hlist_node *n;
 696         unsigned key;
 697
 698         key = type & (EVENT_HASHSIZE - 1);
 699
 700         hlist_for_each_entry(event, n, &event_hash[key], node) {
 701                 if (event->type == type)
 702                         return event;
 703         }
 704
 705         return NULL;
 706 }
 707
 708 static LIST_HEAD(ftrace_event_list);
 709
 710 static int trace_search_list(struct list_head **list)
 711 {
 712         struct trace_event *e;
 713         int last = __TRACE_LAST_TYPE;
 714
 715         if (list_empty(&ftrace_event_list)) {
 716                 *list = &ftrace_event_list;
 717                 return last + 1;
 718         }
 719
 720         /*
 721          * We used up all possible max events,
 722          * lets see if somebody freed one.
 723          */
 724         list_for_each_entry(e, &ftrace_event_list, list) {
 725                 if (e->type != last + 1)
 726                         break;
 727                 last++;
 728         }
 729
 730         /* Did we used up all 65 thousand events??? */
 731         if ((last + 1) > FTRACE_MAX_EVENT)
 732                 return 0;
 733
 734         *list = &e->list;
 735         return last + 1;
 736 }
 737
 738 void trace_event_read_lock(void)
 739 {
 740         down_read(&trace_event_mutex);
 741 }
 742
 743 void trace_event_read_unlock(void)
 744 {
 745         up_read(&trace_event_mutex);
 746 }
 747
 748 /**
 749  * register_ftrace_event - register output for an event type
 750  * @event: the event type to register
 751  *
 752  * Event types are stored in a hash and this hash is used to
 753  * find a way to print an event. If the @event->type is set
 754  * then it will use that type, otherwise it will assign a
 755  * type to use.
 756  *
 757  * If you assign your own type, please make sure it is added
 758  * to the trace_type enum in trace.h, to avoid collisions
 759  * with the dynamic types.
 760  *
 761  * Returns the event type number or zero on error.
 762  */
 763 int register_ftrace_event(struct trace_event *event)
 764 {
 765         unsigned key;
 766         int ret = 0;
 767
 768         down_write(&trace_event_mutex);
 769
 770         if (WARN_ON(!event))
 771                 goto out;
 772
 773         if (WARN_ON(!event->funcs))
 774                 goto out;
 775
 776         INIT_LIST_HEAD(&event->list);
 777
 778         if (!event->type) {
 779                 struct list_head *list = NULL;
 780
 781                 if (next_event_type > FTRACE_MAX_EVENT) {
 782
 783                         event->type = trace_search_list(&list);
 784                         if (!event->type)
 785                                 goto out;
 786
 787                 } else {
 788
 789                         event->type = next_event_type++;
 790                         list = &ftrace_event_list;
 791                 }
 792
 793                 if (WARN_ON(ftrace_find_event(event->type)))
 794                         goto out;
 795
 796                 list_add_tail(&event->list, list);
 797
 798         } else if (event->type > __TRACE_LAST_TYPE) {
 799                 printk(KERN_WARNING "Need to add type to trace.h\n");
 800                 WARN_ON(1);
 801                 goto out;
 802         } else {
 803                 /* Is this event already used */
 804                 if (ftrace_find_event(event->type))
 805                         goto out;
 806         }
 807
 808         if (event->funcs->trace == NULL)
 809                 event->funcs->trace = trace_nop_print;
 810         if (event->funcs->raw == NULL)
 811                 event->funcs->raw = trace_nop_print;
 812         if (event->funcs->hex == NULL)
 813                 event->funcs->hex = trace_nop_print;
 814         if (event->funcs->binary == NULL)
 815                 event->funcs->binary = trace_nop_print;
 816
 817         key = event->type & (EVENT_HASHSIZE - 1);
 818
 819         hlist_add_head(&event->node, &event_hash[key]);
 820
 821         ret = event->type;
 822  out:
 823         up_write(&trace_event_mutex);
 824
 825         return ret;
 826 }
 827 EXPORT_SYMBOL_GPL(register_ftrace_event);
 828
 829 /*
 830  * Used by module code with the trace_event_mutex held for write.
 831  */
 832 int __unregister_ftrace_event(struct trace_event *event)
 833 {
 834         hlist_del(&event->node);
 835         list_del(&event->list);
 836         return 0;
 837 }
 838
 839 /**
 840  * unregister_ftrace_event - remove a no longer used event
 841  * @event: the event to remove
 842  */
 843 int unregister_ftrace_event(struct trace_event *event)
 844 {
 845         down_write(&trace_event_mutex);
 846         __unregister_ftrace_event(event);
 847         up_write(&trace_event_mutex);
 848
 849         return 0;
 850 }
 851 EXPORT_SYMBOL_GPL(unregister_ftrace_event);
 852
 853 /*
 854  * Standard events
 855  */
 856
 857 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
 858                                   struct trace_event *event)
 859 {
 860         if (!trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type))
 861                 return TRACE_TYPE_PARTIAL_LINE;
 862
 863         return TRACE_TYPE_HANDLED;
 864 }
 865
 866 /* TRACE_FN */
 867 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
 868                                         struct trace_event *event)
 869 {
 870         struct ftrace_entry *field;
 871         struct trace_seq *s = &iter->seq;
 872
 873         trace_assign_type(field, iter->ent);
 874
 875         if (!seq_print_ip_sym(s, field->ip, flags))
 876                 goto partial;
 877
 878         if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
 879                 if (!trace_seq_printf(s, " <-"))
 880                         goto partial;
 881                 if (!seq_print_ip_sym(s,
 882                                       field->parent_ip,
 883                                       flags))
 884                         goto partial;
 885         }
 886         if (!trace_seq_printf(s, "\n"))
 887                 goto partial;
 888
 889         return TRACE_TYPE_HANDLED;
 890
 891  partial:
 892         return TRACE_TYPE_PARTIAL_LINE;
 893 }
 894
 895 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
 896                                       struct trace_event *event)
 897 {
 898         struct ftrace_entry *field;
 899
 900         trace_assign_type(field, iter->ent);
 901
 902         if (!trace_seq_printf(&iter->seq, "%lx %lx\n",
 903                               field->ip,
 904                               field->parent_ip))
 905                 return TRACE_TYPE_PARTIAL_LINE;
 906
 907         return TRACE_TYPE_HANDLED;
 908 }
 909
 910 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
 911                                       struct trace_event *event)
 912 {
 913         struct ftrace_entry *field;
 914         struct trace_seq *s = &iter->seq;
 915
 916         trace_assign_type(field, iter->ent);
 917
 918         SEQ_PUT_HEX_FIELD_RET(s, field->ip);
 919         SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
 920
 921         return TRACE_TYPE_HANDLED;
 922 }
 923
 924 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
 925                                       struct trace_event *event)
 926 {
 927         struct ftrace_entry *field;
 928         struct trace_seq *s = &iter->seq;
 929
 930         trace_assign_type(field, iter->ent);
 931
 932         SEQ_PUT_FIELD_RET(s, field->ip);
 933         SEQ_PUT_FIELD_RET(s, field->parent_ip);
 934
 935         return TRACE_TYPE_HANDLED;
 936 }
 937
 938 static struct trace_event_functions trace_fn_funcs = {
 939         .trace          = trace_fn_trace,
 940         .raw            = trace_fn_raw,
 941         .hex            = trace_fn_hex,
 942         .binary         = trace_fn_bin,
 943 };
 944
 945 static struct trace_event trace_fn_event = {
 946         .type           = TRACE_FN,
 947         .funcs          = &trace_fn_funcs,
 948 };
 949
 950 /* TRACE_CTX an TRACE_WAKE */
 951 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
 952                                              char *delim)
 953 {
 954         struct ctx_switch_entry *field;
 955         char comm[TASK_COMM_LEN];
 956         int S, T;
 957
 958
 959         trace_assign_type(field, iter->ent);
 960
 961         T = task_state_char(field->next_state);
 962         S = task_state_char(field->prev_state);
 963         trace_find_cmdline(field->next_pid, comm);
 964         if (!trace_seq_printf(&iter->seq,
 965                               " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
 966                               field->prev_pid,
 967                               field->prev_prio,
 968                               S, delim,
 969                               field->next_cpu,
 970                               field->next_pid,
 971                               field->next_prio,
 972                               T, comm))
 973                 return TRACE_TYPE_PARTIAL_LINE;
 974
 975         return TRACE_TYPE_HANDLED;
 976 }
 977
 978 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
 979                                          struct trace_event *event)
 980 {
 981         return trace_ctxwake_print(iter, "==>");
 982 }
 983
 984 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
 985                                           int flags, struct trace_event *event)
 986 {
 987         return trace_ctxwake_print(iter, "  +");
 988 }
 989
 990 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
 991 {
 992         struct ctx_switch_entry *field;
 993         int T;
 994
 995         trace_assign_type(field, iter->ent);
 996
 997         if (!S)
 998                 S = task_state_char(field->prev_state);
 999         T = task_state_char(field->next_state);
1000         if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
1001                               field->prev_pid,
1002                               field->prev_prio,
1003                               S,
1004                               field->next_cpu,
1005                               field->next_pid,
1006                               field->next_prio,
1007                               T))
1008                 return TRACE_TYPE_PARTIAL_LINE;
1009
1010         return TRACE_TYPE_HANDLED;
1011 }
1012
1013 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
1014                                        struct trace_event *event)
1015 {
1016         return trace_ctxwake_raw(iter, 0);
1017 }
1018
1019 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
1020                                         struct trace_event *event)
1021 {
1022         return trace_ctxwake_raw(iter, '+');
1023 }
1024
1025
1026 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
1027 {
1028         struct ctx_switch_entry *field;
1029         struct trace_seq *s = &iter->seq;
1030         int T;
1031
1032         trace_assign_type(field, iter->ent);
1033
1034         if (!S)
1035                 S = task_state_char(field->prev_state);
1036         T = task_state_char(field->next_state);
1037
1038         SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
1039         SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
1040         SEQ_PUT_HEX_FIELD_RET(s, S);
1041         SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
1042         SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
1043         SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
1044         SEQ_PUT_HEX_FIELD_RET(s, T);
1045
1046         return TRACE_TYPE_HANDLED;
1047 }
1048
1049 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
1050                                        struct trace_event *event)
1051 {
1052         return trace_ctxwake_hex(iter, 0);
1053 }
1054
1055 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
1056                                         struct trace_event *event)
1057 {
1058         return trace_ctxwake_hex(iter, '+');
1059 }
1060
1061 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
1062                                            int flags, struct trace_event *event)
1063 {
1064         struct ctx_switch_entry *field;
1065         struct trace_seq *s = &iter->seq;
1066
1067         trace_assign_type(field, iter->ent);
1068
1069         SEQ_PUT_FIELD_RET(s, field->prev_pid);
1070         SEQ_PUT_FIELD_RET(s, field->prev_prio);
1071         SEQ_PUT_FIELD_RET(s, field->prev_state);
1072         SEQ_PUT_FIELD_RET(s, field->next_pid);
1073         SEQ_PUT_FIELD_RET(s, field->next_prio);
1074         SEQ_PUT_FIELD_RET(s, field->next_state);
1075
1076         return TRACE_TYPE_HANDLED;
1077 }
1078
1079 static struct trace_event_functions trace_ctx_funcs = {
1080         .trace          = trace_ctx_print,
1081         .raw            = trace_ctx_raw,
1082         .hex            = trace_ctx_hex,
1083         .binary         = trace_ctxwake_bin,
1084 };
1085
1086 static struct trace_event trace_ctx_event = {
1087         .type           = TRACE_CTX,
1088         .funcs          = &trace_ctx_funcs,
1089 };
1090
1091 static struct trace_event_functions trace_wake_funcs = {
1092         .trace          = trace_wake_print,
1093         .raw            = trace_wake_raw,
1094         .hex            = trace_wake_hex,
1095         .binary         = trace_ctxwake_bin,
1096 };
1097
1098 static struct trace_event trace_wake_event = {
1099         .type           = TRACE_WAKE,
1100         .funcs          = &trace_wake_funcs,
1101 };
1102
1103 /* TRACE_STACK */
1104
1105 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1106                                            int flags, struct trace_event *event)
1107 {
1108         struct stack_entry *field;
1109         struct trace_seq *s = &iter->seq;
1110         unsigned long *p;
1111         unsigned long *end;
1112
1113         trace_assign_type(field, iter->ent);
1114         end = (unsigned long *)((long)iter->ent + iter->ent_size);
1115
1116         if (!trace_seq_puts(s, "<stack trace>\n"))
1117                 goto partial;
1118
1119         for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
1120                 if (!trace_seq_puts(s, " => "))
1121                         goto partial;
1122
1123                 if (!seq_print_ip_sym(s, *p, flags))
1124                         goto partial;
1125                 if (!trace_seq_puts(s, "\n"))
1126                         goto partial;
1127         }
1128
1129         return TRACE_TYPE_HANDLED;
1130
1131  partial:
1132         return TRACE_TYPE_PARTIAL_LINE;
1133 }
1134
1135 static struct trace_event_functions trace_stack_funcs = {
1136         .trace          = trace_stack_print,
1137 };
1138
1139 static struct trace_event trace_stack_event = {
1140         .type           = TRACE_STACK,
1141         .funcs          = &trace_stack_funcs,
1142 };
1143
1144 /* TRACE_USER_STACK */
1145 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1146                                                 int flags, struct trace_event *event)
1147 {
1148         struct userstack_entry *field;
1149         struct trace_seq *s = &iter->seq;
1150
1151         trace_assign_type(field, iter->ent);
1152
1153         if (!trace_seq_puts(s, "<user stack trace>\n"))
1154                 goto partial;
1155
1156         if (!seq_print_userip_objs(field, s, flags))
1157                 goto partial;
1158
1159         return TRACE_TYPE_HANDLED;
1160
1161  partial:
1162         return TRACE_TYPE_PARTIAL_LINE;
1163 }
1164
1165 static struct trace_event_functions trace_user_stack_funcs = {
1166         .trace          = trace_user_stack_print,
1167 };
1168
1169 static struct trace_event trace_user_stack_event = {
1170         .type           = TRACE_USER_STACK,
1171         .funcs          = &trace_user_stack_funcs,
1172 };
1173
1174 /* TRACE_BPRINT */
1175 static enum print_line_t
1176 trace_bprint_print(struct trace_iterator *iter, int flags,
1177                    struct trace_event *event)
1178 {
1179         struct trace_entry *entry = iter->ent;
1180         struct trace_seq *s = &iter->seq;
1181         struct bprint_entry *field;
1182
1183         trace_assign_type(field, entry);
1184
1185         if (!seq_print_ip_sym(s, field->ip, flags))
1186                 goto partial;
1187
1188         if (!trace_seq_puts(s, ": "))
1189                 goto partial;
1190
1191         if (!trace_seq_bprintf(s, field->fmt, field->buf))
1192                 goto partial;
1193
1194         return TRACE_TYPE_HANDLED;
1195
1196  partial:
1197         return TRACE_TYPE_PARTIAL_LINE;
1198 }
1199
1200
1201 static enum print_line_t
1202 trace_bprint_raw(struct trace_iterator *iter, int flags,
1203                  struct trace_event *event)
1204 {
1205         struct bprint_entry *field;
1206         struct trace_seq *s = &iter->seq;
1207
1208         trace_assign_type(field, iter->ent);
1209
1210         if (!trace_seq_printf(s, ": %lx : ", field->ip))
1211                 goto partial;
1212
1213         if (!trace_seq_bprintf(s, field->fmt, field->buf))
1214                 goto partial;
1215
1216         return TRACE_TYPE_HANDLED;
1217
1218  partial:
1219         return TRACE_TYPE_PARTIAL_LINE;
1220 }
1221
1222 static struct trace_event_functions trace_bprint_funcs = {
1223         .trace          = trace_bprint_print,
1224         .raw            = trace_bprint_raw,
1225 };
1226
1227 static struct trace_event trace_bprint_event = {
1228         .type           = TRACE_BPRINT,
1229         .funcs          = &trace_bprint_funcs,
1230 };
1231
1232 /* TRACE_PRINT */
1233 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1234                                            int flags, struct trace_event *event)
1235 {
1236         struct print_entry *field;
1237         struct trace_seq *s = &iter->seq;
1238
1239         trace_assign_type(field, iter->ent);
1240
1241         if (!seq_print_ip_sym(s, field->ip, flags))
1242                 goto partial;
1243
1244         if (!trace_seq_printf(s, ": %s", field->buf))
1245                 goto partial;
1246
1247         return TRACE_TYPE_HANDLED;
1248
1249  partial:
1250         return TRACE_TYPE_PARTIAL_LINE;
1251 }
1252
1253 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1254                                          struct trace_event *event)
1255 {
1256         struct print_entry *field;
1257
1258         trace_assign_type(field, iter->ent);
1259
1260         if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
1261                 goto partial;
1262
1263         return TRACE_TYPE_HANDLED;
1264
1265  partial:
1266         return TRACE_TYPE_PARTIAL_LINE;
1267 }
1268
1269 static struct trace_event_functions trace_print_funcs = {
1270         .trace          = trace_print_print,
1271         .raw            = trace_print_raw,
1272 };
1273
1274 static struct trace_event trace_print_event = {
1275         .type           = TRACE_PRINT,
1276         .funcs          = &trace_print_funcs,
1277 };
1278
1279
1280 static struct trace_event *events[] __initdata = {
1281         &trace_fn_event,
1282         &trace_ctx_event,
1283         &trace_wake_event,
1284         &trace_stack_event,
1285         &trace_user_stack_event,
1286         &trace_bprint_event,
1287         &trace_print_event,
1288         NULL
1289 };
1290
1291 __init static int init_events(void)
1292 {
1293         struct trace_event *event;
1294         int i, ret;
1295
1296         for (i = 0; events[i]; i++) {
1297                 event = events[i];
1298
1299                 ret = register_ftrace_event(event);
1300                 if (!ret) {
1301                         printk(KERN_WARNING "event %d failed to register\n",
1302                                event->type);
1303                         WARN_ON_ONCE(1);
1304                 }
1305         }
1306
1307         return 0;
1308 }
1309 device_initcall(init_events);