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         int ret;
 631
 632         trace_find_cmdline(entry->pid, comm);
 633
 634         ret = trace_seq_printf(s, "%16s-%-5d [%03d] ",
 635                                comm, entry->pid, iter->cpu);
 636         if (!ret)
 637                 return 0;
 638
 639         if (trace_flags & TRACE_ITER_IRQ_INFO) {
 640                 ret = trace_print_lat_fmt(s, entry);
 641                 if (!ret)
 642                         return 0;
 643         }
 644
 645         return trace_seq_printf(s, " %5lu.%06lu: ",
 646                                 secs, usec_rem);
 647 }
 648
 649 int trace_print_lat_context(struct trace_iterator *iter)
 650 {
 651         u64 next_ts;
 652         int ret;
 653         struct trace_seq *s = &iter->seq;
 654         struct trace_entry *entry = iter->ent,
 655                            *next_entry = trace_find_next_entry(iter, NULL,
 656                                                                &next_ts);
 657         unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
 658         unsigned long abs_usecs = ns2usecs(iter->ts - iter->tr->time_start);
 659         unsigned long rel_usecs;
 660
 661         if (!next_entry)
 662                 next_ts = iter->ts;
 663         rel_usecs = ns2usecs(next_ts - iter->ts);
 664
 665         if (verbose) {
 666                 char comm[TASK_COMM_LEN];
 667
 668                 trace_find_cmdline(entry->pid, comm);
 669
 670                 ret = trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08llx]"
 671                                        " %ld.%03ldms (+%ld.%03ldms): ", comm,
 672                                        entry->pid, iter->cpu, entry->flags,
 673                                        entry->preempt_count, iter->idx,
 674                                        ns2usecs(iter->ts),
 675                                        abs_usecs / USEC_PER_MSEC,
 676                                        abs_usecs % USEC_PER_MSEC,
 677                                        rel_usecs / USEC_PER_MSEC,
 678                                        rel_usecs % USEC_PER_MSEC);
 679         } else {
 680                 ret = lat_print_generic(s, entry, iter->cpu);
 681                 if (ret)
 682                         ret = lat_print_timestamp(s, abs_usecs, rel_usecs);
 683         }
 684
 685         return ret;
 686 }
 687
 688 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
 689
 690 static int task_state_char(unsigned long state)
 691 {
 692         int bit = state ? __ffs(state) + 1 : 0;
 693
 694         return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
 695 }
 696
 697 /**
 698  * ftrace_find_event - find a registered event
 699  * @type: the type of event to look for
 700  *
 701  * Returns an event of type @type otherwise NULL
 702  * Called with trace_event_read_lock() held.
 703  */
 704 struct trace_event *ftrace_find_event(int type)
 705 {
 706         struct trace_event *event;
 707         struct hlist_node *n;
 708         unsigned key;
 709
 710         key = type & (EVENT_HASHSIZE - 1);
 711
 712         hlist_for_each_entry(event, n, &event_hash[key], node) {
 713                 if (event->type == type)
 714                         return event;
 715         }
 716
 717         return NULL;
 718 }
 719
 720 static LIST_HEAD(ftrace_event_list);
 721
 722 static int trace_search_list(struct list_head **list)
 723 {
 724         struct trace_event *e;
 725         int last = __TRACE_LAST_TYPE;
 726
 727         if (list_empty(&ftrace_event_list)) {
 728                 *list = &ftrace_event_list;
 729                 return last + 1;
 730         }
 731
 732         /*
 733          * We used up all possible max events,
 734          * lets see if somebody freed one.
 735          */
 736         list_for_each_entry(e, &ftrace_event_list, list) {
 737                 if (e->type != last + 1)
 738                         break;
 739                 last++;
 740         }
 741
 742         /* Did we used up all 65 thousand events??? */
 743         if ((last + 1) > FTRACE_MAX_EVENT)
 744                 return 0;
 745
 746         *list = &e->list;
 747         return last + 1;
 748 }
 749
 750 void trace_event_read_lock(void)
 751 {
 752         down_read(&trace_event_mutex);
 753 }
 754
 755 void trace_event_read_unlock(void)
 756 {
 757         up_read(&trace_event_mutex);
 758 }
 759
 760 /**
 761  * register_ftrace_event - register output for an event type
 762  * @event: the event type to register
 763  *
 764  * Event types are stored in a hash and this hash is used to
 765  * find a way to print an event. If the @event->type is set
 766  * then it will use that type, otherwise it will assign a
 767  * type to use.
 768  *
 769  * If you assign your own type, please make sure it is added
 770  * to the trace_type enum in trace.h, to avoid collisions
 771  * with the dynamic types.
 772  *
 773  * Returns the event type number or zero on error.
 774  */
 775 int register_ftrace_event(struct trace_event *event)
 776 {
 777         unsigned key;
 778         int ret = 0;
 779
 780         down_write(&trace_event_mutex);
 781
 782         if (WARN_ON(!event))
 783                 goto out;
 784
 785         if (WARN_ON(!event->funcs))
 786                 goto out;
 787
 788         INIT_LIST_HEAD(&event->list);
 789
 790         if (!event->type) {
 791                 struct list_head *list = NULL;
 792
 793                 if (next_event_type > FTRACE_MAX_EVENT) {
 794
 795                         event->type = trace_search_list(&list);
 796                         if (!event->type)
 797                                 goto out;
 798
 799                 } else {
 800
 801                         event->type = next_event_type++;
 802                         list = &ftrace_event_list;
 803                 }
 804
 805                 if (WARN_ON(ftrace_find_event(event->type)))
 806                         goto out;
 807
 808                 list_add_tail(&event->list, list);
 809
 810         } else if (event->type > __TRACE_LAST_TYPE) {
 811                 printk(KERN_WARNING "Need to add type to trace.h\n");
 812                 WARN_ON(1);
 813                 goto out;
 814         } else {
 815                 /* Is this event already used */
 816                 if (ftrace_find_event(event->type))
 817                         goto out;
 818         }
 819
 820         if (event->funcs->trace == NULL)
 821                 event->funcs->trace = trace_nop_print;
 822         if (event->funcs->raw == NULL)
 823                 event->funcs->raw = trace_nop_print;
 824         if (event->funcs->hex == NULL)
 825                 event->funcs->hex = trace_nop_print;
 826         if (event->funcs->binary == NULL)
 827                 event->funcs->binary = trace_nop_print;
 828
 829         key = event->type & (EVENT_HASHSIZE - 1);
 830
 831         hlist_add_head(&event->node, &event_hash[key]);
 832
 833         ret = event->type;
 834  out:
 835         up_write(&trace_event_mutex);
 836
 837         return ret;
 838 }
 839 EXPORT_SYMBOL_GPL(register_ftrace_event);
 840
 841 /*
 842  * Used by module code with the trace_event_mutex held for write.
 843  */
 844 int __unregister_ftrace_event(struct trace_event *event)
 845 {
 846         hlist_del(&event->node);
 847         list_del(&event->list);
 848         return 0;
 849 }
 850
 851 /**
 852  * unregister_ftrace_event - remove a no longer used event
 853  * @event: the event to remove
 854  */
 855 int unregister_ftrace_event(struct trace_event *event)
 856 {
 857         down_write(&trace_event_mutex);
 858         __unregister_ftrace_event(event);
 859         up_write(&trace_event_mutex);
 860
 861         return 0;
 862 }
 863 EXPORT_SYMBOL_GPL(unregister_ftrace_event);
 864
 865 /*
 866  * Standard events
 867  */
 868
 869 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
 870                                   struct trace_event *event)
 871 {
 872         if (!trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type))
 873                 return TRACE_TYPE_PARTIAL_LINE;
 874
 875         return TRACE_TYPE_HANDLED;
 876 }
 877
 878 /* TRACE_FN */
 879 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
 880                                         struct trace_event *event)
 881 {
 882         struct ftrace_entry *field;
 883         struct trace_seq *s = &iter->seq;
 884
 885         trace_assign_type(field, iter->ent);
 886
 887         if (!seq_print_ip_sym(s, field->ip, flags))
 888                 goto partial;
 889
 890         if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
 891                 if (!trace_seq_printf(s, " <-"))
 892                         goto partial;
 893                 if (!seq_print_ip_sym(s,
 894                                       field->parent_ip,
 895                                       flags))
 896                         goto partial;
 897         }
 898         if (!trace_seq_printf(s, "\n"))
 899                 goto partial;
 900
 901         return TRACE_TYPE_HANDLED;
 902
 903  partial:
 904         return TRACE_TYPE_PARTIAL_LINE;
 905 }
 906
 907 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
 908                                       struct trace_event *event)
 909 {
 910         struct ftrace_entry *field;
 911
 912         trace_assign_type(field, iter->ent);
 913
 914         if (!trace_seq_printf(&iter->seq, "%lx %lx\n",
 915                               field->ip,
 916                               field->parent_ip))
 917                 return TRACE_TYPE_PARTIAL_LINE;
 918
 919         return TRACE_TYPE_HANDLED;
 920 }
 921
 922 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
 923                                       struct trace_event *event)
 924 {
 925         struct ftrace_entry *field;
 926         struct trace_seq *s = &iter->seq;
 927
 928         trace_assign_type(field, iter->ent);
 929
 930         SEQ_PUT_HEX_FIELD_RET(s, field->ip);
 931         SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
 932
 933         return TRACE_TYPE_HANDLED;
 934 }
 935
 936 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
 937                                       struct trace_event *event)
 938 {
 939         struct ftrace_entry *field;
 940         struct trace_seq *s = &iter->seq;
 941
 942         trace_assign_type(field, iter->ent);
 943
 944         SEQ_PUT_FIELD_RET(s, field->ip);
 945         SEQ_PUT_FIELD_RET(s, field->parent_ip);
 946
 947         return TRACE_TYPE_HANDLED;
 948 }
 949
 950 static struct trace_event_functions trace_fn_funcs = {
 951         .trace          = trace_fn_trace,
 952         .raw            = trace_fn_raw,
 953         .hex            = trace_fn_hex,
 954         .binary         = trace_fn_bin,
 955 };
 956
 957 static struct trace_event trace_fn_event = {
 958         .type           = TRACE_FN,
 959         .funcs          = &trace_fn_funcs,
 960 };
 961
 962 /* TRACE_CTX an TRACE_WAKE */
 963 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
 964                                              char *delim)
 965 {
 966         struct ctx_switch_entry *field;
 967         char comm[TASK_COMM_LEN];
 968         int S, T;
 969
 970
 971         trace_assign_type(field, iter->ent);
 972
 973         T = task_state_char(field->next_state);
 974         S = task_state_char(field->prev_state);
 975         trace_find_cmdline(field->next_pid, comm);
 976         if (!trace_seq_printf(&iter->seq,
 977                               " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
 978                               field->prev_pid,
 979                               field->prev_prio,
 980                               S, delim,
 981                               field->next_cpu,
 982                               field->next_pid,
 983                               field->next_prio,
 984                               T, comm))
 985                 return TRACE_TYPE_PARTIAL_LINE;
 986
 987         return TRACE_TYPE_HANDLED;
 988 }
 989
 990 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
 991                                          struct trace_event *event)
 992 {
 993         return trace_ctxwake_print(iter, "==>");
 994 }
 995
 996 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
 997                                           int flags, struct trace_event *event)
 998 {
 999         return trace_ctxwake_print(iter, "  +");
1000 }
1001
1002 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
1003 {
1004         struct ctx_switch_entry *field;
1005         int T;
1006
1007         trace_assign_type(field, iter->ent);
1008
1009         if (!S)
1010                 S = task_state_char(field->prev_state);
1011         T = task_state_char(field->next_state);
1012         if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
1013                               field->prev_pid,
1014                               field->prev_prio,
1015                               S,
1016                               field->next_cpu,
1017                               field->next_pid,
1018                               field->next_prio,
1019                               T))
1020                 return TRACE_TYPE_PARTIAL_LINE;
1021
1022         return TRACE_TYPE_HANDLED;
1023 }
1024
1025 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
1026                                        struct trace_event *event)
1027 {
1028         return trace_ctxwake_raw(iter, 0);
1029 }
1030
1031 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
1032                                         struct trace_event *event)
1033 {
1034         return trace_ctxwake_raw(iter, '+');
1035 }
1036
1037
1038 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
1039 {
1040         struct ctx_switch_entry *field;
1041         struct trace_seq *s = &iter->seq;
1042         int T;
1043
1044         trace_assign_type(field, iter->ent);
1045
1046         if (!S)
1047                 S = task_state_char(field->prev_state);
1048         T = task_state_char(field->next_state);
1049
1050         SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
1051         SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
1052         SEQ_PUT_HEX_FIELD_RET(s, S);
1053         SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
1054         SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
1055         SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
1056         SEQ_PUT_HEX_FIELD_RET(s, T);
1057
1058         return TRACE_TYPE_HANDLED;
1059 }
1060
1061 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
1062                                        struct trace_event *event)
1063 {
1064         return trace_ctxwake_hex(iter, 0);
1065 }
1066
1067 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
1068                                         struct trace_event *event)
1069 {
1070         return trace_ctxwake_hex(iter, '+');
1071 }
1072
1073 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
1074                                            int flags, struct trace_event *event)
1075 {
1076         struct ctx_switch_entry *field;
1077         struct trace_seq *s = &iter->seq;
1078
1079         trace_assign_type(field, iter->ent);
1080
1081         SEQ_PUT_FIELD_RET(s, field->prev_pid);
1082         SEQ_PUT_FIELD_RET(s, field->prev_prio);
1083         SEQ_PUT_FIELD_RET(s, field->prev_state);
1084         SEQ_PUT_FIELD_RET(s, field->next_pid);
1085         SEQ_PUT_FIELD_RET(s, field->next_prio);
1086         SEQ_PUT_FIELD_RET(s, field->next_state);
1087
1088         return TRACE_TYPE_HANDLED;
1089 }
1090
1091 static struct trace_event_functions trace_ctx_funcs = {
1092         .trace          = trace_ctx_print,
1093         .raw            = trace_ctx_raw,
1094         .hex            = trace_ctx_hex,
1095         .binary         = trace_ctxwake_bin,
1096 };
1097
1098 static struct trace_event trace_ctx_event = {
1099         .type           = TRACE_CTX,
1100         .funcs          = &trace_ctx_funcs,
1101 };
1102
1103 static struct trace_event_functions trace_wake_funcs = {
1104         .trace          = trace_wake_print,
1105         .raw            = trace_wake_raw,
1106         .hex            = trace_wake_hex,
1107         .binary         = trace_ctxwake_bin,
1108 };
1109
1110 static struct trace_event trace_wake_event = {
1111         .type           = TRACE_WAKE,
1112         .funcs          = &trace_wake_funcs,
1113 };
1114
1115 /* TRACE_STACK */
1116
1117 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1118                                            int flags, struct trace_event *event)
1119 {
1120         struct stack_entry *field;
1121         struct trace_seq *s = &iter->seq;
1122         unsigned long *p;
1123         unsigned long *end;
1124
1125         trace_assign_type(field, iter->ent);
1126         end = (unsigned long *)((long)iter->ent + iter->ent_size);
1127
1128         if (!trace_seq_puts(s, "<stack trace>\n"))
1129                 goto partial;
1130
1131         for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
1132                 if (!trace_seq_puts(s, " => "))
1133                         goto partial;
1134
1135                 if (!seq_print_ip_sym(s, *p, flags))
1136                         goto partial;
1137                 if (!trace_seq_puts(s, "\n"))
1138                         goto partial;
1139         }
1140
1141         return TRACE_TYPE_HANDLED;
1142
1143  partial:
1144         return TRACE_TYPE_PARTIAL_LINE;
1145 }
1146
1147 static struct trace_event_functions trace_stack_funcs = {
1148         .trace          = trace_stack_print,
1149 };
1150
1151 static struct trace_event trace_stack_event = {
1152         .type           = TRACE_STACK,
1153         .funcs          = &trace_stack_funcs,
1154 };
1155
1156 /* TRACE_USER_STACK */
1157 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1158                                                 int flags, struct trace_event *event)
1159 {
1160         struct userstack_entry *field;
1161         struct trace_seq *s = &iter->seq;
1162
1163         trace_assign_type(field, iter->ent);
1164
1165         if (!trace_seq_puts(s, "<user stack trace>\n"))
1166                 goto partial;
1167
1168         if (!seq_print_userip_objs(field, s, flags))
1169                 goto partial;
1170
1171         return TRACE_TYPE_HANDLED;
1172
1173  partial:
1174         return TRACE_TYPE_PARTIAL_LINE;
1175 }
1176
1177 static struct trace_event_functions trace_user_stack_funcs = {
1178         .trace          = trace_user_stack_print,
1179 };
1180
1181 static struct trace_event trace_user_stack_event = {
1182         .type           = TRACE_USER_STACK,
1183         .funcs          = &trace_user_stack_funcs,
1184 };
1185
1186 /* TRACE_BPRINT */
1187 static enum print_line_t
1188 trace_bprint_print(struct trace_iterator *iter, int flags,
1189                    struct trace_event *event)
1190 {
1191         struct trace_entry *entry = iter->ent;
1192         struct trace_seq *s = &iter->seq;
1193         struct bprint_entry *field;
1194
1195         trace_assign_type(field, entry);
1196
1197         if (!seq_print_ip_sym(s, field->ip, flags))
1198                 goto partial;
1199
1200         if (!trace_seq_puts(s, ": "))
1201                 goto partial;
1202
1203         if (!trace_seq_bprintf(s, field->fmt, field->buf))
1204                 goto partial;
1205
1206         return TRACE_TYPE_HANDLED;
1207
1208  partial:
1209         return TRACE_TYPE_PARTIAL_LINE;
1210 }
1211
1212
1213 static enum print_line_t
1214 trace_bprint_raw(struct trace_iterator *iter, int flags,
1215                  struct trace_event *event)
1216 {
1217         struct bprint_entry *field;
1218         struct trace_seq *s = &iter->seq;
1219
1220         trace_assign_type(field, iter->ent);
1221
1222         if (!trace_seq_printf(s, ": %lx : ", field->ip))
1223                 goto partial;
1224
1225         if (!trace_seq_bprintf(s, field->fmt, field->buf))
1226                 goto partial;
1227
1228         return TRACE_TYPE_HANDLED;
1229
1230  partial:
1231         return TRACE_TYPE_PARTIAL_LINE;
1232 }
1233
1234 static struct trace_event_functions trace_bprint_funcs = {
1235         .trace          = trace_bprint_print,
1236         .raw            = trace_bprint_raw,
1237 };
1238
1239 static struct trace_event trace_bprint_event = {
1240         .type           = TRACE_BPRINT,
1241         .funcs          = &trace_bprint_funcs,
1242 };
1243
1244 /* TRACE_PRINT */
1245 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1246                                            int flags, struct trace_event *event)
1247 {
1248         struct print_entry *field;
1249         struct trace_seq *s = &iter->seq;
1250
1251         trace_assign_type(field, iter->ent);
1252
1253         if (!seq_print_ip_sym(s, field->ip, flags))
1254                 goto partial;
1255
1256         if (!trace_seq_printf(s, ": %s", field->buf))
1257                 goto partial;
1258
1259         return TRACE_TYPE_HANDLED;
1260
1261  partial:
1262         return TRACE_TYPE_PARTIAL_LINE;
1263 }
1264
1265 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1266                                          struct trace_event *event)
1267 {
1268         struct print_entry *field;
1269
1270         trace_assign_type(field, iter->ent);
1271
1272         if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
1273                 goto partial;
1274
1275         return TRACE_TYPE_HANDLED;
1276
1277  partial:
1278         return TRACE_TYPE_PARTIAL_LINE;
1279 }
1280
1281 static struct trace_event_functions trace_print_funcs = {
1282         .trace          = trace_print_print,
1283         .raw            = trace_print_raw,
1284 };
1285
1286 static struct trace_event trace_print_event = {
1287         .type           = TRACE_PRINT,
1288         .funcs          = &trace_print_funcs,
1289 };
1290
1291
1292 static struct trace_event *events[] __initdata = {
1293         &trace_fn_event,
1294         &trace_ctx_event,
1295         &trace_wake_event,
1296         &trace_stack_event,
1297         &trace_user_stack_event,
1298         &trace_bprint_event,
1299         &trace_print_event,
1300         NULL
1301 };
1302
1303 __init static int init_events(void)
1304 {
1305         struct trace_event *event;
1306         int i, ret;
1307
1308         for (i = 0; events[i]; i++) {
1309                 event = events[i];
1310
1311                 ret = register_ftrace_event(event);
1312                 if (!ret) {
1313                         printk(KERN_WARNING "event %d failed to register\n",
1314                                event->type);
1315                         WARN_ON_ONCE(1);
1316                 }
1317         }
1318
1319         return 0;
1320 }
1321 device_initcall(init_events);