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, const 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, first = 1;
 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 (!first && delim)
 314                         trace_seq_puts(p, delim);
 315                 else
 316                         first = 0;
 317                 trace_seq_puts(p, str);
 318         }
 319
 320         /* check for left over flags */
 321         if (flags) {
 322                 if (!first && delim)
 323                         trace_seq_puts(p, delim);
 324                 trace_seq_printf(p, "0x%lx", flags);
 325         }
 326
 327         trace_seq_putc(p, 0);
 328
 329         return ret;
 330 }
 331 EXPORT_SYMBOL(ftrace_print_flags_seq);
 332
 333 const char *
 334 ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
 335                          const struct trace_print_flags *symbol_array)
 336 {
 337         int i;
 338         const char *ret = p->buffer + p->len;
 339
 340         for (i = 0;  symbol_array[i].name; i++) {
 341
 342                 if (val != symbol_array[i].mask)
 343                         continue;
 344
 345                 trace_seq_puts(p, symbol_array[i].name);
 346                 break;
 347         }
 348
 349         if (ret == (const char *)(p->buffer + p->len))
 350                 trace_seq_printf(p, "0x%lx", val);
 351
 352         trace_seq_putc(p, 0);
 353
 354         return ret;
 355 }
 356 EXPORT_SYMBOL(ftrace_print_symbols_seq);
 357
 358 #if BITS_PER_LONG == 32
 359 const char *
 360 ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
 361                          const struct trace_print_flags_u64 *symbol_array)
 362 {
 363         int i;
 364         const char *ret = p->buffer + p->len;
 365
 366         for (i = 0;  symbol_array[i].name; i++) {
 367
 368                 if (val != symbol_array[i].mask)
 369                         continue;
 370
 371                 trace_seq_puts(p, symbol_array[i].name);
 372                 break;
 373         }
 374
 375         if (ret == (const char *)(p->buffer + p->len))
 376                 trace_seq_printf(p, "0x%llx", val);
 377
 378         trace_seq_putc(p, 0);
 379
 380         return ret;
 381 }
 382 EXPORT_SYMBOL(ftrace_print_symbols_seq_u64);
 383 #endif
 384
 385 const char *
 386 ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
 387 {
 388         int i;
 389         const char *ret = p->buffer + p->len;
 390
 391         for (i = 0; i < buf_len; i++)
 392                 trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
 393
 394         trace_seq_putc(p, 0);
 395
 396         return ret;
 397 }
 398 EXPORT_SYMBOL(ftrace_print_hex_seq);
 399
 400 #ifdef CONFIG_KRETPROBES
 401 static inline const char *kretprobed(const char *name)
 402 {
 403         static const char tramp_name[] = "kretprobe_trampoline";
 404         int size = sizeof(tramp_name);
 405
 406         if (strncmp(tramp_name, name, size) == 0)
 407                 return "[unknown/kretprobe'd]";
 408         return name;
 409 }
 410 #else
 411 static inline const char *kretprobed(const char *name)
 412 {
 413         return name;
 414 }
 415 #endif /* CONFIG_KRETPROBES */
 416
 417 static int
 418 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
 419 {
 420 #ifdef CONFIG_KALLSYMS
 421         char str[KSYM_SYMBOL_LEN];
 422         const char *name;
 423
 424         kallsyms_lookup(address, NULL, NULL, NULL, str);
 425
 426         name = kretprobed(str);
 427
 428         return trace_seq_printf(s, fmt, name);
 429 #endif
 430         return 1;
 431 }
 432
 433 static int
 434 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
 435                      unsigned long address)
 436 {
 437 #ifdef CONFIG_KALLSYMS
 438         char str[KSYM_SYMBOL_LEN];
 439         const char *name;
 440
 441         sprint_symbol(str, address);
 442         name = kretprobed(str);
 443
 444         return trace_seq_printf(s, fmt, name);
 445 #endif
 446         return 1;
 447 }
 448
 449 #ifndef CONFIG_64BIT
 450 # define IP_FMT "%08lx"
 451 #else
 452 # define IP_FMT "%016lx"
 453 #endif
 454
 455 int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
 456                       unsigned long ip, unsigned long sym_flags)
 457 {
 458         struct file *file = NULL;
 459         unsigned long vmstart = 0;
 460         int ret = 1;
 461
 462         if (s->full)
 463                 return 0;
 464
 465         if (mm) {
 466                 const struct vm_area_struct *vma;
 467
 468                 down_read(&mm->mmap_sem);
 469                 vma = find_vma(mm, ip);
 470                 if (vma) {
 471                         file = vma->vm_file;
 472                         vmstart = vma->vm_start;
 473                 }
 474                 if (file) {
 475                         ret = trace_seq_path(s, &file->f_path);
 476                         if (ret)
 477                                 ret = trace_seq_printf(s, "[+0x%lx]",
 478                                                        ip - vmstart);
 479                 }
 480                 up_read(&mm->mmap_sem);
 481         }
 482         if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
 483                 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
 484         return ret;
 485 }
 486
 487 int
 488 seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
 489                       unsigned long sym_flags)
 490 {
 491         struct mm_struct *mm = NULL;
 492         int ret = 1;
 493         unsigned int i;
 494
 495         if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
 496                 struct task_struct *task;
 497                 /*
 498                  * we do the lookup on the thread group leader,
 499                  * since individual threads might have already quit!
 500                  */
 501                 rcu_read_lock();
 502                 task = find_task_by_vpid(entry->tgid);
 503                 if (task)
 504                         mm = get_task_mm(task);
 505                 rcu_read_unlock();
 506         }
 507
 508         for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
 509                 unsigned long ip = entry->caller[i];
 510
 511                 if (ip == ULONG_MAX || !ret)
 512                         break;
 513                 if (ret)
 514                         ret = trace_seq_puts(s, " => ");
 515                 if (!ip) {
 516                         if (ret)
 517                                 ret = trace_seq_puts(s, "??");
 518                         if (ret)
 519                                 ret = trace_seq_puts(s, "\n");
 520                         continue;
 521                 }
 522                 if (!ret)
 523                         break;
 524                 if (ret)
 525                         ret = seq_print_user_ip(s, mm, ip, sym_flags);
 526                 ret = trace_seq_puts(s, "\n");
 527         }
 528
 529         if (mm)
 530                 mmput(mm);
 531         return ret;
 532 }
 533
 534 int
 535 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
 536 {
 537         int ret;
 538
 539         if (!ip)
 540                 return trace_seq_printf(s, "0");
 541
 542         if (sym_flags & TRACE_ITER_SYM_OFFSET)
 543                 ret = seq_print_sym_offset(s, "%s", ip);
 544         else
 545                 ret = seq_print_sym_short(s, "%s", ip);
 546
 547         if (!ret)
 548                 return 0;
 549
 550         if (sym_flags & TRACE_ITER_SYM_ADDR)
 551                 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
 552         return ret;
 553 }
 554
 555 /**
 556  * trace_print_lat_fmt - print the irq, preempt and lockdep fields
 557  * @s: trace seq struct to write to
 558  * @entry: The trace entry field from the ring buffer
 559  *
 560  * Prints the generic fields of irqs off, in hard or softirq, preempt
 561  * count.
 562  */
 563 int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 564 {
 565         char hardsoft_irq;
 566         char need_resched;
 567         char irqs_off;
 568         int hardirq;
 569         int softirq;
 570         int ret;
 571
 572         hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
 573         softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
 574
 575         irqs_off =
 576                 (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
 577                 (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
 578                 '.';
 579         need_resched =
 580                 (entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.';
 581         hardsoft_irq =
 582                 (hardirq && softirq) ? 'H' :
 583                 hardirq ? 'h' :
 584                 softirq ? 's' :
 585                 '.';
 586
 587         if (!trace_seq_printf(s, "%c%c%c",
 588                               irqs_off, need_resched, hardsoft_irq))
 589                 return 0;
 590
 591         if (entry->preempt_count)
 592                 ret = trace_seq_printf(s, "%x", entry->preempt_count);
 593         else
 594                 ret = trace_seq_putc(s, '.');
 595
 596         return ret;
 597 }
 598
 599 static int
 600 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
 601 {
 602         char comm[TASK_COMM_LEN];
 603
 604         trace_find_cmdline(entry->pid, comm);
 605
 606         if (!trace_seq_printf(s, "%8.8s-%-5d %3d",
 607                               comm, entry->pid, cpu))
 608                 return 0;
 609
 610         return trace_print_lat_fmt(s, entry);
 611 }
 612
 613 static unsigned long preempt_mark_thresh_us = 100;
 614
 615 static int
 616 lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
 617 {
 618         unsigned long verbose = trace_flags & TRACE_ITER_VERBOSE;
 619         unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
 620         unsigned long long abs_ts = iter->ts - iter->tr->time_start;
 621         unsigned long long rel_ts = next_ts - iter->ts;
 622         struct trace_seq *s = &iter->seq;
 623
 624         if (in_ns) {
 625                 abs_ts = ns2usecs(abs_ts);
 626                 rel_ts = ns2usecs(rel_ts);
 627         }
 628
 629         if (verbose && in_ns) {
 630                 unsigned long abs_usec = do_div(abs_ts, USEC_PER_MSEC);
 631                 unsigned long abs_msec = (unsigned long)abs_ts;
 632                 unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
 633                 unsigned long rel_msec = (unsigned long)rel_ts;
 634
 635                 return trace_seq_printf(
 636                                 s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
 637                                 ns2usecs(iter->ts),
 638                                 abs_msec, abs_usec,
 639                                 rel_msec, rel_usec);
 640         } else if (verbose && !in_ns) {
 641                 return trace_seq_printf(
 642                                 s, "[%016llx] %lld (+%lld): ",
 643                                 iter->ts, abs_ts, rel_ts);
 644         } else if (!verbose && in_ns) {
 645                 return trace_seq_printf(
 646                                 s, " %4lldus%c: ",
 647                                 abs_ts,
 648                                 rel_ts > preempt_mark_thresh_us ? '!' :
 649                                   rel_ts > 1 ? '+' : ' ');
 650         } else { /* !verbose && !in_ns */
 651                 return trace_seq_printf(s, " %4lld: ", abs_ts);
 652         }
 653 }
 654
 655 int trace_print_context(struct trace_iterator *iter)
 656 {
 657         struct trace_seq *s = &iter->seq;
 658         struct trace_entry *entry = iter->ent;
 659         unsigned long long t;
 660         unsigned long secs, usec_rem;
 661         char comm[TASK_COMM_LEN];
 662         int ret;
 663
 664         trace_find_cmdline(entry->pid, comm);
 665
 666         ret = trace_seq_printf(s, "%16s-%-5d [%03d] ",
 667                                comm, entry->pid, iter->cpu);
 668         if (!ret)
 669                 return 0;
 670
 671         if (trace_flags & TRACE_ITER_IRQ_INFO) {
 672                 ret = trace_print_lat_fmt(s, entry);
 673                 if (!ret)
 674                         return 0;
 675         }
 676
 677         if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
 678                 t = ns2usecs(iter->ts);
 679                 usec_rem = do_div(t, USEC_PER_SEC);
 680                 secs = (unsigned long)t;
 681                 return trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
 682         } else
 683                 return trace_seq_printf(s, " %12llu: ", iter->ts);
 684 }
 685
 686 int trace_print_lat_context(struct trace_iterator *iter)
 687 {
 688         u64 next_ts;
 689         int ret;
 690         /* trace_find_next_entry will reset ent_size */
 691         int ent_size = iter->ent_size;
 692         struct trace_seq *s = &iter->seq;
 693         struct trace_entry *entry = iter->ent,
 694                            *next_entry = trace_find_next_entry(iter, NULL,
 695                                                                &next_ts);
 696         unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
 697
 698         /* Restore the original ent_size */
 699         iter->ent_size = ent_size;
 700
 701         if (!next_entry)
 702                 next_ts = iter->ts;
 703
 704         if (verbose) {
 705                 char comm[TASK_COMM_LEN];
 706
 707                 trace_find_cmdline(entry->pid, comm);
 708
 709                 ret = trace_seq_printf(
 710                                 s, "%16s %5d %3d %d %08x %08lx ",
 711                                 comm, entry->pid, iter->cpu, entry->flags,
 712                                 entry->preempt_count, iter->idx);
 713         } else {
 714                 ret = lat_print_generic(s, entry, iter->cpu);
 715         }
 716
 717         if (ret)
 718                 ret = lat_print_timestamp(iter, next_ts);
 719
 720         return ret;
 721 }
 722
 723 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
 724
 725 static int task_state_char(unsigned long state)
 726 {
 727         int bit = state ? __ffs(state) + 1 : 0;
 728
 729         return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
 730 }
 731
 732 /**
 733  * ftrace_find_event - find a registered event
 734  * @type: the type of event to look for
 735  *
 736  * Returns an event of type @type otherwise NULL
 737  * Called with trace_event_read_lock() held.
 738  */
 739 struct trace_event *ftrace_find_event(int type)
 740 {
 741         struct trace_event *event;
 742         struct hlist_node *n;
 743         unsigned key;
 744
 745         key = type & (EVENT_HASHSIZE - 1);
 746
 747         hlist_for_each_entry(event, n, &event_hash[key], node) {
 748                 if (event->type == type)
 749                         return event;
 750         }
 751
 752         return NULL;
 753 }
 754
 755 static LIST_HEAD(ftrace_event_list);
 756
 757 static int trace_search_list(struct list_head **list)
 758 {
 759         struct trace_event *e;
 760         int last = __TRACE_LAST_TYPE;
 761
 762         if (list_empty(&ftrace_event_list)) {
 763                 *list = &ftrace_event_list;
 764                 return last + 1;
 765         }
 766
 767         /*
 768          * We used up all possible max events,
 769          * lets see if somebody freed one.
 770          */
 771         list_for_each_entry(e, &ftrace_event_list, list) {
 772                 if (e->type != last + 1)
 773                         break;
 774                 last++;
 775         }
 776
 777         /* Did we used up all 65 thousand events??? */
 778         if ((last + 1) > FTRACE_MAX_EVENT)
 779                 return 0;
 780
 781         *list = &e->list;
 782         return last + 1;
 783 }
 784
 785 void trace_event_read_lock(void)
 786 {
 787         down_read(&trace_event_mutex);
 788 }
 789
 790 void trace_event_read_unlock(void)
 791 {
 792         up_read(&trace_event_mutex);
 793 }
 794
 795 /**
 796  * register_ftrace_event - register output for an event type
 797  * @event: the event type to register
 798  *
 799  * Event types are stored in a hash and this hash is used to
 800  * find a way to print an event. If the @event->type is set
 801  * then it will use that type, otherwise it will assign a
 802  * type to use.
 803  *
 804  * If you assign your own type, please make sure it is added
 805  * to the trace_type enum in trace.h, to avoid collisions
 806  * with the dynamic types.
 807  *
 808  * Returns the event type number or zero on error.
 809  */
 810 int register_ftrace_event(struct trace_event *event)
 811 {
 812         unsigned key;
 813         int ret = 0;
 814
 815         down_write(&trace_event_mutex);
 816
 817         if (WARN_ON(!event))
 818                 goto out;
 819
 820         if (WARN_ON(!event->funcs))
 821                 goto out;
 822
 823         INIT_LIST_HEAD(&event->list);
 824
 825         if (!event->type) {
 826                 struct list_head *list = NULL;
 827
 828                 if (next_event_type > FTRACE_MAX_EVENT) {
 829
 830                         event->type = trace_search_list(&list);
 831                         if (!event->type)
 832                                 goto out;
 833
 834                 } else {
 835
 836                         event->type = next_event_type++;
 837                         list = &ftrace_event_list;
 838                 }
 839
 840                 if (WARN_ON(ftrace_find_event(event->type)))
 841                         goto out;
 842
 843                 list_add_tail(&event->list, list);
 844
 845         } else if (event->type > __TRACE_LAST_TYPE) {
 846                 printk(KERN_WARNING "Need to add type to trace.h\n");
 847                 WARN_ON(1);
 848                 goto out;
 849         } else {
 850                 /* Is this event already used */
 851                 if (ftrace_find_event(event->type))
 852                         goto out;
 853         }
 854
 855         if (event->funcs->trace == NULL)
 856                 event->funcs->trace = trace_nop_print;
 857         if (event->funcs->raw == NULL)
 858                 event->funcs->raw = trace_nop_print;
 859         if (event->funcs->hex == NULL)
 860                 event->funcs->hex = trace_nop_print;
 861         if (event->funcs->binary == NULL)
 862                 event->funcs->binary = trace_nop_print;
 863
 864         key = event->type & (EVENT_HASHSIZE - 1);
 865
 866         hlist_add_head(&event->node, &event_hash[key]);
 867
 868         ret = event->type;
 869  out:
 870         up_write(&trace_event_mutex);
 871
 872         return ret;
 873 }
 874 EXPORT_SYMBOL_GPL(register_ftrace_event);
 875
 876 /*
 877  * Used by module code with the trace_event_mutex held for write.
 878  */
 879 int __unregister_ftrace_event(struct trace_event *event)
 880 {
 881         hlist_del(&event->node);
 882         list_del(&event->list);
 883         return 0;
 884 }
 885
 886 /**
 887  * unregister_ftrace_event - remove a no longer used event
 888  * @event: the event to remove
 889  */
 890 int unregister_ftrace_event(struct trace_event *event)
 891 {
 892         down_write(&trace_event_mutex);
 893         __unregister_ftrace_event(event);
 894         up_write(&trace_event_mutex);
 895
 896         return 0;
 897 }
 898 EXPORT_SYMBOL_GPL(unregister_ftrace_event);
 899
 900 /*
 901  * Standard events
 902  */
 903
 904 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
 905                                   struct trace_event *event)
 906 {
 907         if (!trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type))
 908                 return TRACE_TYPE_PARTIAL_LINE;
 909
 910         return TRACE_TYPE_HANDLED;
 911 }
 912
 913 /* TRACE_FN */
 914 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
 915                                         struct trace_event *event)
 916 {
 917         struct ftrace_entry *field;
 918         struct trace_seq *s = &iter->seq;
 919
 920         trace_assign_type(field, iter->ent);
 921
 922         if (!seq_print_ip_sym(s, field->ip, flags))
 923                 goto partial;
 924
 925         if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
 926                 if (!trace_seq_printf(s, " <-"))
 927                         goto partial;
 928                 if (!seq_print_ip_sym(s,
 929                                       field->parent_ip,
 930                                       flags))
 931                         goto partial;
 932         }
 933         if (!trace_seq_printf(s, "\n"))
 934                 goto partial;
 935
 936         return TRACE_TYPE_HANDLED;
 937
 938  partial:
 939         return TRACE_TYPE_PARTIAL_LINE;
 940 }
 941
 942 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
 943                                       struct trace_event *event)
 944 {
 945         struct ftrace_entry *field;
 946
 947         trace_assign_type(field, iter->ent);
 948
 949         if (!trace_seq_printf(&iter->seq, "%lx %lx\n",
 950                               field->ip,
 951                               field->parent_ip))
 952                 return TRACE_TYPE_PARTIAL_LINE;
 953
 954         return TRACE_TYPE_HANDLED;
 955 }
 956
 957 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
 958                                       struct trace_event *event)
 959 {
 960         struct ftrace_entry *field;
 961         struct trace_seq *s = &iter->seq;
 962
 963         trace_assign_type(field, iter->ent);
 964
 965         SEQ_PUT_HEX_FIELD_RET(s, field->ip);
 966         SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
 967
 968         return TRACE_TYPE_HANDLED;
 969 }
 970
 971 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
 972                                       struct trace_event *event)
 973 {
 974         struct ftrace_entry *field;
 975         struct trace_seq *s = &iter->seq;
 976
 977         trace_assign_type(field, iter->ent);
 978
 979         SEQ_PUT_FIELD_RET(s, field->ip);
 980         SEQ_PUT_FIELD_RET(s, field->parent_ip);
 981
 982         return TRACE_TYPE_HANDLED;
 983 }
 984
 985 static struct trace_event_functions trace_fn_funcs = {
 986         .trace          = trace_fn_trace,
 987         .raw            = trace_fn_raw,
 988         .hex            = trace_fn_hex,
 989         .binary         = trace_fn_bin,
 990 };
 991
 992 static struct trace_event trace_fn_event = {
 993         .type           = TRACE_FN,
 994         .funcs          = &trace_fn_funcs,
 995 };
 996
 997 /* TRACE_CTX an TRACE_WAKE */
 998 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
 999                                              char *delim)
1000 {
1001         struct ctx_switch_entry *field;
1002         char comm[TASK_COMM_LEN];
1003         int S, T;
1004
1005
1006         trace_assign_type(field, iter->ent);
1007
1008         T = task_state_char(field->next_state);
1009         S = task_state_char(field->prev_state);
1010         trace_find_cmdline(field->next_pid, comm);
1011         if (!trace_seq_printf(&iter->seq,
1012                               " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
1013                               field->prev_pid,
1014                               field->prev_prio,
1015                               S, delim,
1016                               field->next_cpu,
1017                               field->next_pid,
1018                               field->next_prio,
1019                               T, comm))
1020                 return TRACE_TYPE_PARTIAL_LINE;
1021
1022         return TRACE_TYPE_HANDLED;
1023 }
1024
1025 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
1026                                          struct trace_event *event)
1027 {
1028         return trace_ctxwake_print(iter, "==>");
1029 }
1030
1031 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
1032                                           int flags, struct trace_event *event)
1033 {
1034         return trace_ctxwake_print(iter, "  +");
1035 }
1036
1037 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
1038 {
1039         struct ctx_switch_entry *field;
1040         int T;
1041
1042         trace_assign_type(field, iter->ent);
1043
1044         if (!S)
1045                 S = task_state_char(field->prev_state);
1046         T = task_state_char(field->next_state);
1047         if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
1048                               field->prev_pid,
1049                               field->prev_prio,
1050                               S,
1051                               field->next_cpu,
1052                               field->next_pid,
1053                               field->next_prio,
1054                               T))
1055                 return TRACE_TYPE_PARTIAL_LINE;
1056
1057         return TRACE_TYPE_HANDLED;
1058 }
1059
1060 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
1061                                        struct trace_event *event)
1062 {
1063         return trace_ctxwake_raw(iter, 0);
1064 }
1065
1066 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
1067                                         struct trace_event *event)
1068 {
1069         return trace_ctxwake_raw(iter, '+');
1070 }
1071
1072
1073 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
1074 {
1075         struct ctx_switch_entry *field;
1076         struct trace_seq *s = &iter->seq;
1077         int T;
1078
1079         trace_assign_type(field, iter->ent);
1080
1081         if (!S)
1082                 S = task_state_char(field->prev_state);
1083         T = task_state_char(field->next_state);
1084
1085         SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
1086         SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
1087         SEQ_PUT_HEX_FIELD_RET(s, S);
1088         SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
1089         SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
1090         SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
1091         SEQ_PUT_HEX_FIELD_RET(s, T);
1092
1093         return TRACE_TYPE_HANDLED;
1094 }
1095
1096 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
1097                                        struct trace_event *event)
1098 {
1099         return trace_ctxwake_hex(iter, 0);
1100 }
1101
1102 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
1103                                         struct trace_event *event)
1104 {
1105         return trace_ctxwake_hex(iter, '+');
1106 }
1107
1108 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
1109                                            int flags, struct trace_event *event)
1110 {
1111         struct ctx_switch_entry *field;
1112         struct trace_seq *s = &iter->seq;
1113
1114         trace_assign_type(field, iter->ent);
1115
1116         SEQ_PUT_FIELD_RET(s, field->prev_pid);
1117         SEQ_PUT_FIELD_RET(s, field->prev_prio);
1118         SEQ_PUT_FIELD_RET(s, field->prev_state);
1119         SEQ_PUT_FIELD_RET(s, field->next_pid);
1120         SEQ_PUT_FIELD_RET(s, field->next_prio);
1121         SEQ_PUT_FIELD_RET(s, field->next_state);
1122
1123         return TRACE_TYPE_HANDLED;
1124 }
1125
1126 static struct trace_event_functions trace_ctx_funcs = {
1127         .trace          = trace_ctx_print,
1128         .raw            = trace_ctx_raw,
1129         .hex            = trace_ctx_hex,
1130         .binary         = trace_ctxwake_bin,
1131 };
1132
1133 static struct trace_event trace_ctx_event = {
1134         .type           = TRACE_CTX,
1135         .funcs          = &trace_ctx_funcs,
1136 };
1137
1138 static struct trace_event_functions trace_wake_funcs = {
1139         .trace          = trace_wake_print,
1140         .raw            = trace_wake_raw,
1141         .hex            = trace_wake_hex,
1142         .binary         = trace_ctxwake_bin,
1143 };
1144
1145 static struct trace_event trace_wake_event = {
1146         .type           = TRACE_WAKE,
1147         .funcs          = &trace_wake_funcs,
1148 };
1149
1150 /* TRACE_STACK */
1151
1152 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1153                                            int flags, struct trace_event *event)
1154 {
1155         struct stack_entry *field;
1156         struct trace_seq *s = &iter->seq;
1157         unsigned long *p;
1158         unsigned long *end;
1159
1160         trace_assign_type(field, iter->ent);
1161         end = (unsigned long *)((long)iter->ent + iter->ent_size);
1162
1163         if (!trace_seq_puts(s, "<stack trace>\n"))
1164                 goto partial;
1165
1166         for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
1167                 if (!trace_seq_puts(s, " => "))
1168                         goto partial;
1169
1170                 if (!seq_print_ip_sym(s, *p, flags))
1171                         goto partial;
1172                 if (!trace_seq_puts(s, "\n"))
1173                         goto partial;
1174         }
1175
1176         return TRACE_TYPE_HANDLED;
1177
1178  partial:
1179         return TRACE_TYPE_PARTIAL_LINE;
1180 }
1181
1182 static struct trace_event_functions trace_stack_funcs = {
1183         .trace          = trace_stack_print,
1184 };
1185
1186 static struct trace_event trace_stack_event = {
1187         .type           = TRACE_STACK,
1188         .funcs          = &trace_stack_funcs,
1189 };
1190
1191 /* TRACE_USER_STACK */
1192 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1193                                                 int flags, struct trace_event *event)
1194 {
1195         struct userstack_entry *field;
1196         struct trace_seq *s = &iter->seq;
1197
1198         trace_assign_type(field, iter->ent);
1199
1200         if (!trace_seq_puts(s, "<user stack trace>\n"))
1201                 goto partial;
1202
1203         if (!seq_print_userip_objs(field, s, flags))
1204                 goto partial;
1205
1206         return TRACE_TYPE_HANDLED;
1207
1208  partial:
1209         return TRACE_TYPE_PARTIAL_LINE;
1210 }
1211
1212 static struct trace_event_functions trace_user_stack_funcs = {
1213         .trace          = trace_user_stack_print,
1214 };
1215
1216 static struct trace_event trace_user_stack_event = {
1217         .type           = TRACE_USER_STACK,
1218         .funcs          = &trace_user_stack_funcs,
1219 };
1220
1221 /* TRACE_BPRINT */
1222 static enum print_line_t
1223 trace_bprint_print(struct trace_iterator *iter, int flags,
1224                    struct trace_event *event)
1225 {
1226         struct trace_entry *entry = iter->ent;
1227         struct trace_seq *s = &iter->seq;
1228         struct bprint_entry *field;
1229
1230         trace_assign_type(field, entry);
1231
1232         if (!seq_print_ip_sym(s, field->ip, flags))
1233                 goto partial;
1234
1235         if (!trace_seq_puts(s, ": "))
1236                 goto partial;
1237
1238         if (!trace_seq_bprintf(s, field->fmt, field->buf))
1239                 goto partial;
1240
1241         return TRACE_TYPE_HANDLED;
1242
1243  partial:
1244         return TRACE_TYPE_PARTIAL_LINE;
1245 }
1246
1247
1248 static enum print_line_t
1249 trace_bprint_raw(struct trace_iterator *iter, int flags,
1250                  struct trace_event *event)
1251 {
1252         struct bprint_entry *field;
1253         struct trace_seq *s = &iter->seq;
1254
1255         trace_assign_type(field, iter->ent);
1256
1257         if (!trace_seq_printf(s, ": %lx : ", field->ip))
1258                 goto partial;
1259
1260         if (!trace_seq_bprintf(s, field->fmt, 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_bprint_funcs = {
1270         .trace          = trace_bprint_print,
1271         .raw            = trace_bprint_raw,
1272 };
1273
1274 static struct trace_event trace_bprint_event = {
1275         .type           = TRACE_BPRINT,
1276         .funcs          = &trace_bprint_funcs,
1277 };
1278
1279 /* TRACE_PRINT */
1280 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1281                                            int flags, struct trace_event *event)
1282 {
1283         struct print_entry *field;
1284         struct trace_seq *s = &iter->seq;
1285
1286         trace_assign_type(field, iter->ent);
1287
1288         if (!seq_print_ip_sym(s, field->ip, flags))
1289                 goto partial;
1290
1291         if (!trace_seq_printf(s, ": %s", field->buf))
1292                 goto partial;
1293
1294         return TRACE_TYPE_HANDLED;
1295
1296  partial:
1297         return TRACE_TYPE_PARTIAL_LINE;
1298 }
1299
1300 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1301                                          struct trace_event *event)
1302 {
1303         struct print_entry *field;
1304
1305         trace_assign_type(field, iter->ent);
1306
1307         if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
1308                 goto partial;
1309
1310         return TRACE_TYPE_HANDLED;
1311
1312  partial:
1313         return TRACE_TYPE_PARTIAL_LINE;
1314 }
1315
1316 static struct trace_event_functions trace_print_funcs = {
1317         .trace          = trace_print_print,
1318         .raw            = trace_print_raw,
1319 };
1320
1321 static struct trace_event trace_print_event = {
1322         .type           = TRACE_PRINT,
1323         .funcs          = &trace_print_funcs,
1324 };
1325
1326
1327 static struct trace_event *events[] __initdata = {
1328         &trace_fn_event,
1329         &trace_ctx_event,
1330         &trace_wake_event,
1331         &trace_stack_event,
1332         &trace_user_stack_event,
1333         &trace_bprint_event,
1334         &trace_print_event,
1335         NULL
1336 };
1337
1338 __init static int init_events(void)
1339 {
1340         struct trace_event *event;
1341         int i, ret;
1342
1343         for (i = 0; events[i]; i++) {
1344                 event = events[i];
1345
1346                 ret = register_ftrace_event(event);
1347                 if (!ret) {
1348                         printk(KERN_WARNING "event %d failed to register\n",
1349                                event->type);
1350                         WARN_ON_ONCE(1);
1351                 }
1352         }
1353
1354         return 0;
1355 }
1356 early_initcall(init_events);