kernel/trace/trace_output.c

   1 /*
   2  * trace_output.c
   3  *
   4  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
   5  *
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/mutex.h>
  10 #include <linux/ftrace.h>
  11
  12 #include "trace_output.h"
  13
  14 /* must be a power of 2 */
  15 #define EVENT_HASHSIZE  128
  16
  17 DECLARE_RWSEM(trace_event_sem);
  18
  19 static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
  20
  21 static int next_event_type = __TRACE_LAST_TYPE + 1;
  22
  23 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_bputs_msg_only(struct trace_iterator *iter)
  41 {
  42         struct trace_seq *s = &iter->seq;
  43         struct trace_entry *entry = iter->ent;
  44         struct bputs_entry *field;
  45         int ret;
  46
  47         trace_assign_type(field, entry);
  48
  49         ret = trace_seq_puts(s, field->str);
  50         if (!ret)
  51                 return TRACE_TYPE_PARTIAL_LINE;
  52
  53         return TRACE_TYPE_HANDLED;
  54 }
  55
  56 enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
  57 {
  58         struct trace_seq *s = &iter->seq;
  59         struct trace_entry *entry = iter->ent;
  60         struct bprint_entry *field;
  61         int ret;
  62
  63         trace_assign_type(field, entry);
  64
  65         ret = trace_seq_bprintf(s, field->fmt, field->buf);
  66         if (!ret)
  67                 return TRACE_TYPE_PARTIAL_LINE;
  68
  69         return TRACE_TYPE_HANDLED;
  70 }
  71
  72 enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
  73 {
  74         struct trace_seq *s = &iter->seq;
  75         struct trace_entry *entry = iter->ent;
  76         struct print_entry *field;
  77         int ret;
  78
  79         trace_assign_type(field, entry);
  80
  81         ret = trace_seq_printf(s, "%s", field->buf);
  82         if (!ret)
  83                 return TRACE_TYPE_PARTIAL_LINE;
  84
  85         return TRACE_TYPE_HANDLED;
  86 }
  87
  88 /**
  89  * trace_seq_printf - sequence printing of trace information
  90  * @s: trace sequence descriptor
  91  * @fmt: printf format string
  92  *
  93  * It returns 0 if the trace oversizes the buffer's free
  94  * space, 1 otherwise.
  95  *
  96  * The tracer may use either sequence operations or its own
  97  * copy to user routines. To simplify formating of a trace
  98  * trace_seq_printf is used to store strings into a special
  99  * buffer (@s). Then the output may be either used by
 100  * the sequencer or pulled into another buffer.
 101  */
 102 int
 103 trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 104 {
 105         int len = (PAGE_SIZE - 1) - s->len;
 106         va_list ap;
 107         int ret;
 108
 109         if (s->full || !len)
 110                 return 0;
 111
 112         va_start(ap, fmt);
 113         ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
 114         va_end(ap);
 115
 116         /* If we can't write it all, don't bother writing anything */
 117         if (ret >= len) {
 118                 s->full = 1;
 119                 return 0;
 120         }
 121
 122         s->len += ret;
 123
 124         return 1;
 125 }
 126 EXPORT_SYMBOL_GPL(trace_seq_printf);
 127
 128 /**
 129  * trace_seq_vprintf - sequence printing of trace information
 130  * @s: trace sequence descriptor
 131  * @fmt: printf format string
 132  *
 133  * The tracer may use either sequence operations or its own
 134  * copy to user routines. To simplify formating of a trace
 135  * trace_seq_printf is used to store strings into a special
 136  * buffer (@s). Then the output may be either used by
 137  * the sequencer or pulled into another buffer.
 138  */
 139 int
 140 trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
 141 {
 142         int len = (PAGE_SIZE - 1) - s->len;
 143         int ret;
 144
 145         if (s->full || !len)
 146                 return 0;
 147
 148         ret = vsnprintf(s->buffer + s->len, len, fmt, args);
 149
 150         /* If we can't write it all, don't bother writing anything */
 151         if (ret >= len) {
 152                 s->full = 1;
 153                 return 0;
 154         }
 155
 156         s->len += ret;
 157
 158         return len;
 159 }
 160 EXPORT_SYMBOL_GPL(trace_seq_vprintf);
 161
 162 int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 163 {
 164         int len = (PAGE_SIZE - 1) - s->len;
 165         int ret;
 166
 167         if (s->full || !len)
 168                 return 0;
 169
 170         ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
 171
 172         /* If we can't write it all, don't bother writing anything */
 173         if (ret >= len) {
 174                 s->full = 1;
 175                 return 0;
 176         }
 177
 178         s->len += ret;
 179
 180         return len;
 181 }
 182
 183 /**
 184  * trace_seq_puts - trace sequence printing of simple string
 185  * @s: trace sequence descriptor
 186  * @str: simple string to record
 187  *
 188  * The tracer may use either the sequence operations or its own
 189  * copy to user routines. This function records a simple string
 190  * into a special buffer (@s) for later retrieval by a sequencer
 191  * or other mechanism.
 192  */
 193 int trace_seq_puts(struct trace_seq *s, const char *str)
 194 {
 195         int len = strlen(str);
 196
 197         if (s->full)
 198                 return 0;
 199
 200         if (len > ((PAGE_SIZE - 1) - s->len)) {
 201                 s->full = 1;
 202                 return 0;
 203         }
 204
 205         memcpy(s->buffer + s->len, str, len);
 206         s->len += len;
 207
 208         return len;
 209 }
 210
 211 int trace_seq_putc(struct trace_seq *s, unsigned char c)
 212 {
 213         if (s->full)
 214                 return 0;
 215
 216         if (s->len >= (PAGE_SIZE - 1)) {
 217                 s->full = 1;
 218                 return 0;
 219         }
 220
 221         s->buffer[s->len++] = c;
 222
 223         return 1;
 224 }
 225 EXPORT_SYMBOL(trace_seq_putc);
 226
 227 int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len)
 228 {
 229         if (s->full)
 230                 return 0;
 231
 232         if (len > ((PAGE_SIZE - 1) - s->len)) {
 233                 s->full = 1;
 234                 return 0;
 235         }
 236
 237         memcpy(s->buffer + s->len, mem, len);
 238         s->len += len;
 239
 240         return len;
 241 }
 242
 243 int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len)
 244 {
 245         unsigned char hex[HEX_CHARS];
 246         const unsigned char *data = mem;
 247         int i, j;
 248
 249         if (s->full)
 250                 return 0;
 251
 252 #ifdef __BIG_ENDIAN
 253         for (i = 0, j = 0; i < len; i++) {
 254 #else
 255         for (i = len-1, j = 0; i >= 0; i--) {
 256 #endif
 257                 hex[j++] = hex_asc_hi(data[i]);
 258                 hex[j++] = hex_asc_lo(data[i]);
 259         }
 260         hex[j++] = ' ';
 261
 262         return trace_seq_putmem(s, hex, j);
 263 }
 264
 265 void *trace_seq_reserve(struct trace_seq *s, size_t len)
 266 {
 267         void *ret;
 268
 269         if (s->full)
 270                 return NULL;
 271
 272         if (len > ((PAGE_SIZE - 1) - s->len)) {
 273                 s->full = 1;
 274                 return NULL;
 275         }
 276
 277         ret = s->buffer + s->len;
 278         s->len += len;
 279
 280         return ret;
 281 }
 282
 283 int trace_seq_path(struct trace_seq *s, const struct path *path)
 284 {
 285         unsigned char *p;
 286
 287         if (s->full)
 288                 return 0;
 289
 290         if (s->len >= (PAGE_SIZE - 1)) {
 291                 s->full = 1;
 292                 return 0;
 293         }
 294
 295         p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
 296         if (!IS_ERR(p)) {
 297                 p = mangle_path(s->buffer + s->len, p, "\n");
 298                 if (p) {
 299                         s->len = p - s->buffer;
 300                         return 1;
 301                 }
 302         } else {
 303                 s->buffer[s->len++] = '?';
 304                 return 1;
 305         }
 306
 307         s->full = 1;
 308         return 0;
 309 }
 310
 311 const char *
 312 ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
 313                        unsigned long flags,
 314                        const struct trace_print_flags *flag_array)
 315 {
 316         unsigned long mask;
 317         const char *str;
 318         const char *ret = p->buffer + p->len;
 319         int i, first = 1;
 320
 321         for (i = 0;  flag_array[i].name && flags; i++) {
 322
 323                 mask = flag_array[i].mask;
 324                 if ((flags & mask) != mask)
 325                         continue;
 326
 327                 str = flag_array[i].name;
 328                 flags &= ~mask;
 329                 if (!first && delim)
 330                         trace_seq_puts(p, delim);
 331                 else
 332                         first = 0;
 333                 trace_seq_puts(p, str);
 334         }
 335
 336         /* check for left over flags */
 337         if (flags) {
 338                 if (!first && delim)
 339                         trace_seq_puts(p, delim);
 340                 trace_seq_printf(p, "0x%lx", flags);
 341         }
 342
 343         trace_seq_putc(p, 0);
 344
 345         return ret;
 346 }
 347 EXPORT_SYMBOL(ftrace_print_flags_seq);
 348
 349 const char *
 350 ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
 351                          const struct trace_print_flags *symbol_array)
 352 {
 353         int i;
 354         const char *ret = p->buffer + p->len;
 355
 356         for (i = 0;  symbol_array[i].name; i++) {
 357
 358                 if (val != symbol_array[i].mask)
 359                         continue;
 360
 361                 trace_seq_puts(p, symbol_array[i].name);
 362                 break;
 363         }
 364
 365         if (ret == (const char *)(p->buffer + p->len))
 366                 trace_seq_printf(p, "0x%lx", val);
 367
 368         trace_seq_putc(p, 0);
 369
 370         return ret;
 371 }
 372 EXPORT_SYMBOL(ftrace_print_symbols_seq);
 373
 374 #if BITS_PER_LONG == 32
 375 const char *
 376 ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
 377                          const struct trace_print_flags_u64 *symbol_array)
 378 {
 379         int i;
 380         const char *ret = p->buffer + p->len;
 381
 382         for (i = 0;  symbol_array[i].name; i++) {
 383
 384                 if (val != symbol_array[i].mask)
 385                         continue;
 386
 387                 trace_seq_puts(p, symbol_array[i].name);
 388                 break;
 389         }
 390
 391         if (ret == (const char *)(p->buffer + p->len))
 392                 trace_seq_printf(p, "0x%llx", val);
 393
 394         trace_seq_putc(p, 0);
 395
 396         return ret;
 397 }
 398 EXPORT_SYMBOL(ftrace_print_symbols_seq_u64);
 399 #endif
 400
 401 const char *
 402 ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
 403 {
 404         int i;
 405         const char *ret = p->buffer + p->len;
 406
 407         for (i = 0; i < buf_len; i++)
 408                 trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
 409
 410         trace_seq_putc(p, 0);
 411
 412         return ret;
 413 }
 414 EXPORT_SYMBOL(ftrace_print_hex_seq);
 415
 416 int ftrace_raw_output_prep(struct trace_iterator *iter,
 417                            struct trace_event *trace_event)
 418 {
 419         struct ftrace_event_call *event;
 420         struct trace_seq *s = &iter->seq;
 421         struct trace_seq *p = &iter->tmp_seq;
 422         struct trace_entry *entry;
 423         int ret;
 424
 425         event = container_of(trace_event, struct ftrace_event_call, event);
 426         entry = iter->ent;
 427
 428         if (entry->type != event->event.type) {
 429                 WARN_ON_ONCE(1);
 430                 return TRACE_TYPE_UNHANDLED;
 431         }
 432
 433         trace_seq_init(p);
 434         ret = trace_seq_printf(s, "%s: ", event->name);
 435         if (!ret)
 436                 return TRACE_TYPE_PARTIAL_LINE;
 437
 438         return 0;
 439 }
 440 EXPORT_SYMBOL(ftrace_raw_output_prep);
 441
 442 #ifdef CONFIG_KRETPROBES
 443 static inline const char *kretprobed(const char *name)
 444 {
 445         static const char tramp_name[] = "kretprobe_trampoline";
 446         int size = sizeof(tramp_name);
 447
 448         if (strncmp(tramp_name, name, size) == 0)
 449                 return "[unknown/kretprobe'd]";
 450         return name;
 451 }
 452 #else
 453 static inline const char *kretprobed(const char *name)
 454 {
 455         return name;
 456 }
 457 #endif /* CONFIG_KRETPROBES */
 458
 459 static int
 460 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
 461 {
 462 #ifdef CONFIG_KALLSYMS
 463         char str[KSYM_SYMBOL_LEN];
 464         const char *name;
 465
 466         kallsyms_lookup(address, NULL, NULL, NULL, str);
 467
 468         name = kretprobed(str);
 469
 470         return trace_seq_printf(s, fmt, name);
 471 #endif
 472         return 1;
 473 }
 474
 475 static int
 476 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
 477                      unsigned long address)
 478 {
 479 #ifdef CONFIG_KALLSYMS
 480         char str[KSYM_SYMBOL_LEN];
 481         const char *name;
 482
 483         sprint_symbol(str, address);
 484         name = kretprobed(str);
 485
 486         return trace_seq_printf(s, fmt, name);
 487 #endif
 488         return 1;
 489 }
 490
 491 #ifndef CONFIG_64BIT
 492 # define IP_FMT "%08lx"
 493 #else
 494 # define IP_FMT "%016lx"
 495 #endif
 496
 497 int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
 498                       unsigned long ip, unsigned long sym_flags)
 499 {
 500         struct file *file = NULL;
 501         unsigned long vmstart = 0;
 502         int ret = 1;
 503
 504         if (s->full)
 505                 return 0;
 506
 507         if (mm) {
 508                 const struct vm_area_struct *vma;
 509
 510                 down_read(&mm->mmap_sem);
 511                 vma = find_vma(mm, ip);
 512                 if (vma) {
 513                         file = vma->vm_file;
 514                         vmstart = vma->vm_start;
 515                 }
 516                 if (file) {
 517                         ret = trace_seq_path(s, &file->f_path);
 518                         if (ret)
 519                                 ret = trace_seq_printf(s, "[+0x%lx]",
 520                                                        ip - vmstart);
 521                 }
 522                 up_read(&mm->mmap_sem);
 523         }
 524         if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
 525                 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
 526         return ret;
 527 }
 528
 529 int
 530 seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
 531                       unsigned long sym_flags)
 532 {
 533         struct mm_struct *mm = NULL;
 534         int ret = 1;
 535         unsigned int i;
 536
 537         if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
 538                 struct task_struct *task;
 539                 /*
 540                  * we do the lookup on the thread group leader,
 541                  * since individual threads might have already quit!
 542                  */
 543                 rcu_read_lock();
 544                 task = find_task_by_vpid(entry->tgid);
 545                 if (task)
 546                         mm = get_task_mm(task);
 547                 rcu_read_unlock();
 548         }
 549
 550         for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
 551                 unsigned long ip = entry->caller[i];
 552
 553                 if (ip == ULONG_MAX || !ret)
 554                         break;
 555                 if (ret)
 556                         ret = trace_seq_puts(s, " => ");
 557                 if (!ip) {
 558                         if (ret)
 559                                 ret = trace_seq_puts(s, "??");
 560                         if (ret)
 561                                 ret = trace_seq_puts(s, "\n");
 562                         continue;
 563                 }
 564                 if (!ret)
 565                         break;
 566                 if (ret)
 567                         ret = seq_print_user_ip(s, mm, ip, sym_flags);
 568                 ret = trace_seq_puts(s, "\n");
 569         }
 570
 571         if (mm)
 572                 mmput(mm);
 573         return ret;
 574 }
 575
 576 int
 577 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
 578 {
 579         int ret;
 580
 581         if (!ip)
 582                 return trace_seq_printf(s, "0");
 583
 584         if (sym_flags & TRACE_ITER_SYM_OFFSET)
 585                 ret = seq_print_sym_offset(s, "%s", ip);
 586         else
 587                 ret = seq_print_sym_short(s, "%s", ip);
 588
 589         if (!ret)
 590                 return 0;
 591
 592         if (sym_flags & TRACE_ITER_SYM_ADDR)
 593                 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
 594         return ret;
 595 }
 596
 597 /**
 598  * trace_print_lat_fmt - print the irq, preempt and lockdep fields
 599  * @s: trace seq struct to write to
 600  * @entry: The trace entry field from the ring buffer
 601  *
 602  * Prints the generic fields of irqs off, in hard or softirq, preempt
 603  * count.
 604  */
 605 int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 606 {
 607         char hardsoft_irq;
 608         char need_resched;
 609         char irqs_off;
 610         int hardirq;
 611         int softirq;
 612         int ret;
 613
 614         hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
 615         softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
 616
 617         irqs_off =
 618                 (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
 619                 (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
 620                 '.';
 621         need_resched =
 622                 (entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.';
 623         hardsoft_irq =
 624                 (hardirq && softirq) ? 'H' :
 625                 hardirq ? 'h' :
 626                 softirq ? 's' :
 627                 '.';
 628
 629         if (!trace_seq_printf(s, "%c%c%c",
 630                               irqs_off, need_resched, hardsoft_irq))
 631                 return 0;
 632
 633         if (entry->preempt_count)
 634                 ret = trace_seq_printf(s, "%x", entry->preempt_count);
 635         else
 636                 ret = trace_seq_putc(s, '.');
 637
 638         return ret;
 639 }
 640
 641 static int
 642 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
 643 {
 644         char comm[TASK_COMM_LEN];
 645
 646         trace_find_cmdline(entry->pid, comm);
 647
 648         if (!trace_seq_printf(s, "%8.8s-%-5d %3d",
 649                               comm, entry->pid, cpu))
 650                 return 0;
 651
 652         return trace_print_lat_fmt(s, entry);
 653 }
 654
 655 static unsigned long preempt_mark_thresh_us = 100;
 656
 657 static int
 658 lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
 659 {
 660         unsigned long verbose = trace_flags & TRACE_ITER_VERBOSE;
 661         unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
 662         unsigned long long abs_ts = iter->ts - iter->trace_buffer->time_start;
 663         unsigned long long rel_ts = next_ts - iter->ts;
 664         struct trace_seq *s = &iter->seq;
 665
 666         if (in_ns) {
 667                 abs_ts = ns2usecs(abs_ts);
 668                 rel_ts = ns2usecs(rel_ts);
 669         }
 670
 671         if (verbose && in_ns) {
 672                 unsigned long abs_usec = do_div(abs_ts, USEC_PER_MSEC);
 673                 unsigned long abs_msec = (unsigned long)abs_ts;
 674                 unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
 675                 unsigned long rel_msec = (unsigned long)rel_ts;
 676
 677                 return trace_seq_printf(
 678                                 s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
 679                                 ns2usecs(iter->ts),
 680                                 abs_msec, abs_usec,
 681                                 rel_msec, rel_usec);
 682         } else if (verbose && !in_ns) {
 683                 return trace_seq_printf(
 684                                 s, "[%016llx] %lld (+%lld): ",
 685                                 iter->ts, abs_ts, rel_ts);
 686         } else if (!verbose && in_ns) {
 687                 return trace_seq_printf(
 688                                 s, " %4lldus%c: ",
 689                                 abs_ts,
 690                                 rel_ts > preempt_mark_thresh_us ? '!' :
 691                                   rel_ts > 1 ? '+' : ' ');
 692         } else { /* !verbose && !in_ns */
 693                 return trace_seq_printf(s, " %4lld: ", abs_ts);
 694         }
 695 }
 696
 697 int trace_print_context(struct trace_iterator *iter)
 698 {
 699         struct trace_seq *s = &iter->seq;
 700         struct trace_entry *entry = iter->ent;
 701         unsigned long long t;
 702         unsigned long secs, usec_rem;
 703         char comm[TASK_COMM_LEN];
 704         int ret;
 705
 706         trace_find_cmdline(entry->pid, comm);
 707
 708         ret = trace_seq_printf(s, "%16s-%-5d [%03d] ",
 709                                comm, entry->pid, iter->cpu);
 710         if (!ret)
 711                 return 0;
 712
 713         if (trace_flags & TRACE_ITER_IRQ_INFO) {
 714                 ret = trace_print_lat_fmt(s, entry);
 715                 if (!ret)
 716                         return 0;
 717         }
 718
 719         if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
 720                 t = ns2usecs(iter->ts);
 721                 usec_rem = do_div(t, USEC_PER_SEC);
 722                 secs = (unsigned long)t;
 723                 return trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
 724         } else
 725                 return trace_seq_printf(s, " %12llu: ", iter->ts);
 726 }
 727
 728 int trace_print_lat_context(struct trace_iterator *iter)
 729 {
 730         u64 next_ts;
 731         int ret;
 732         /* trace_find_next_entry will reset ent_size */
 733         int ent_size = iter->ent_size;
 734         struct trace_seq *s = &iter->seq;
 735         struct trace_entry *entry = iter->ent,
 736                            *next_entry = trace_find_next_entry(iter, NULL,
 737                                                                &next_ts);
 738         unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
 739
 740         /* Restore the original ent_size */
 741         iter->ent_size = ent_size;
 742
 743         if (!next_entry)
 744                 next_ts = iter->ts;
 745
 746         if (verbose) {
 747                 char comm[TASK_COMM_LEN];
 748
 749                 trace_find_cmdline(entry->pid, comm);
 750
 751                 ret = trace_seq_printf(
 752                                 s, "%16s %5d %3d %d %08x %08lx ",
 753                                 comm, entry->pid, iter->cpu, entry->flags,
 754                                 entry->preempt_count, iter->idx);
 755         } else {
 756                 ret = lat_print_generic(s, entry, iter->cpu);
 757         }
 758
 759         if (ret)
 760                 ret = lat_print_timestamp(iter, next_ts);
 761
 762         return ret;
 763 }
 764
 765 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
 766
 767 static int task_state_char(unsigned long state)
 768 {
 769         int bit = state ? __ffs(state) + 1 : 0;
 770
 771         return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
 772 }
 773
 774 /**
 775  * ftrace_find_event - find a registered event
 776  * @type: the type of event to look for
 777  *
 778  * Returns an event of type @type otherwise NULL
 779  * Called with trace_event_read_lock() held.
 780  */
 781 struct trace_event *ftrace_find_event(int type)
 782 {
 783         struct trace_event *event;
 784         unsigned key;
 785
 786         key = type & (EVENT_HASHSIZE - 1);
 787
 788         hlist_for_each_entry(event, &event_hash[key], node) {
 789                 if (event->type == type)
 790                         return event;
 791         }
 792
 793         return NULL;
 794 }
 795
 796 static LIST_HEAD(ftrace_event_list);
 797
 798 static int trace_search_list(struct list_head **list)
 799 {
 800         struct trace_event *e;
 801         int last = __TRACE_LAST_TYPE;
 802
 803         if (list_empty(&ftrace_event_list)) {
 804                 *list = &ftrace_event_list;
 805                 return last + 1;
 806         }
 807
 808         /*
 809          * We used up all possible max events,
 810          * lets see if somebody freed one.
 811          */
 812         list_for_each_entry(e, &ftrace_event_list, list) {
 813                 if (e->type != last + 1)
 814                         break;
 815                 last++;
 816         }
 817
 818         /* Did we used up all 65 thousand events??? */
 819         if ((last + 1) > FTRACE_MAX_EVENT)
 820                 return 0;
 821
 822         *list = &e->list;
 823         return last + 1;
 824 }
 825
 826 void trace_event_read_lock(void)
 827 {
 828         down_read(&trace_event_sem);
 829 }
 830
 831 void trace_event_read_unlock(void)
 832 {
 833         up_read(&trace_event_sem);
 834 }
 835
 836 /**
 837  * register_ftrace_event - register output for an event type
 838  * @event: the event type to register
 839  *
 840  * Event types are stored in a hash and this hash is used to
 841  * find a way to print an event. If the @event->type is set
 842  * then it will use that type, otherwise it will assign a
 843  * type to use.
 844  *
 845  * If you assign your own type, please make sure it is added
 846  * to the trace_type enum in trace.h, to avoid collisions
 847  * with the dynamic types.
 848  *
 849  * Returns the event type number or zero on error.
 850  */
 851 int register_ftrace_event(struct trace_event *event)
 852 {
 853         unsigned key;
 854         int ret = 0;
 855
 856         down_write(&trace_event_sem);
 857
 858         if (WARN_ON(!event))
 859                 goto out;
 860
 861         if (WARN_ON(!event->funcs))
 862                 goto out;
 863
 864         INIT_LIST_HEAD(&event->list);
 865
 866         if (!event->type) {
 867                 struct list_head *list = NULL;
 868
 869                 if (next_event_type > FTRACE_MAX_EVENT) {
 870
 871                         event->type = trace_search_list(&list);
 872                         if (!event->type)
 873                                 goto out;
 874
 875                 } else {
 876
 877                         event->type = next_event_type++;
 878                         list = &ftrace_event_list;
 879                 }
 880
 881                 if (WARN_ON(ftrace_find_event(event->type)))
 882                         goto out;
 883
 884                 list_add_tail(&event->list, list);
 885
 886         } else if (event->type > __TRACE_LAST_TYPE) {
 887                 printk(KERN_WARNING "Need to add type to trace.h\n");
 888                 WARN_ON(1);
 889                 goto out;
 890         } else {
 891                 /* Is this event already used */
 892                 if (ftrace_find_event(event->type))
 893                         goto out;
 894         }
 895
 896         if (event->funcs->trace == NULL)
 897                 event->funcs->trace = trace_nop_print;
 898         if (event->funcs->raw == NULL)
 899                 event->funcs->raw = trace_nop_print;
 900         if (event->funcs->hex == NULL)
 901                 event->funcs->hex = trace_nop_print;
 902         if (event->funcs->binary == NULL)
 903                 event->funcs->binary = trace_nop_print;
 904
 905         key = event->type & (EVENT_HASHSIZE - 1);
 906
 907         hlist_add_head(&event->node, &event_hash[key]);
 908
 909         ret = event->type;
 910  out:
 911         up_write(&trace_event_sem);
 912
 913         return ret;
 914 }
 915 EXPORT_SYMBOL_GPL(register_ftrace_event);
 916
 917 /*
 918  * Used by module code with the trace_event_sem held for write.
 919  */
 920 int __unregister_ftrace_event(struct trace_event *event)
 921 {
 922         hlist_del(&event->node);
 923         list_del(&event->list);
 924         return 0;
 925 }
 926
 927 /**
 928  * unregister_ftrace_event - remove a no longer used event
 929  * @event: the event to remove
 930  */
 931 int unregister_ftrace_event(struct trace_event *event)
 932 {
 933         down_write(&trace_event_sem);
 934         __unregister_ftrace_event(event);
 935         up_write(&trace_event_sem);
 936
 937         return 0;
 938 }
 939 EXPORT_SYMBOL_GPL(unregister_ftrace_event);
 940
 941 /*
 942  * Standard events
 943  */
 944
 945 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
 946                                   struct trace_event *event)
 947 {
 948         if (!trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type))
 949                 return TRACE_TYPE_PARTIAL_LINE;
 950
 951         return TRACE_TYPE_HANDLED;
 952 }
 953
 954 /* TRACE_FN */
 955 static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
 956                                         struct trace_event *event)
 957 {
 958         struct ftrace_entry *field;
 959         struct trace_seq *s = &iter->seq;
 960
 961         trace_assign_type(field, iter->ent);
 962
 963         if (!seq_print_ip_sym(s, field->ip, flags))
 964                 goto partial;
 965
 966         if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
 967                 if (!trace_seq_printf(s, " <-"))
 968                         goto partial;
 969                 if (!seq_print_ip_sym(s,
 970                                       field->parent_ip,
 971                                       flags))
 972                         goto partial;
 973         }
 974         if (!trace_seq_printf(s, "\n"))
 975                 goto partial;
 976
 977         return TRACE_TYPE_HANDLED;
 978
 979  partial:
 980         return TRACE_TYPE_PARTIAL_LINE;
 981 }
 982
 983 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
 984                                       struct trace_event *event)
 985 {
 986         struct ftrace_entry *field;
 987
 988         trace_assign_type(field, iter->ent);
 989
 990         if (!trace_seq_printf(&iter->seq, "%lx %lx\n",
 991                               field->ip,
 992                               field->parent_ip))
 993                 return TRACE_TYPE_PARTIAL_LINE;
 994
 995         return TRACE_TYPE_HANDLED;
 996 }
 997
 998 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
 999                                       struct trace_event *event)
1000 {
1001         struct ftrace_entry *field;
1002         struct trace_seq *s = &iter->seq;
1003
1004         trace_assign_type(field, iter->ent);
1005
1006         SEQ_PUT_HEX_FIELD_RET(s, field->ip);
1007         SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
1008
1009         return TRACE_TYPE_HANDLED;
1010 }
1011
1012 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
1013                                       struct trace_event *event)
1014 {
1015         struct ftrace_entry *field;
1016         struct trace_seq *s = &iter->seq;
1017
1018         trace_assign_type(field, iter->ent);
1019
1020         SEQ_PUT_FIELD_RET(s, field->ip);
1021         SEQ_PUT_FIELD_RET(s, field->parent_ip);
1022
1023         return TRACE_TYPE_HANDLED;
1024 }
1025
1026 static struct trace_event_functions trace_fn_funcs = {
1027         .trace          = trace_fn_trace,
1028         .raw            = trace_fn_raw,
1029         .hex            = trace_fn_hex,
1030         .binary         = trace_fn_bin,
1031 };
1032
1033 static struct trace_event trace_fn_event = {
1034         .type           = TRACE_FN,
1035         .funcs          = &trace_fn_funcs,
1036 };
1037
1038 /* TRACE_CTX an TRACE_WAKE */
1039 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
1040                                              char *delim)
1041 {
1042         struct ctx_switch_entry *field;
1043         char comm[TASK_COMM_LEN];
1044         int S, T;
1045
1046
1047         trace_assign_type(field, iter->ent);
1048
1049         T = task_state_char(field->next_state);
1050         S = task_state_char(field->prev_state);
1051         trace_find_cmdline(field->next_pid, comm);
1052         if (!trace_seq_printf(&iter->seq,
1053                               " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
1054                               field->prev_pid,
1055                               field->prev_prio,
1056                               S, delim,
1057                               field->next_cpu,
1058                               field->next_pid,
1059                               field->next_prio,
1060                               T, comm))
1061                 return TRACE_TYPE_PARTIAL_LINE;
1062
1063         return TRACE_TYPE_HANDLED;
1064 }
1065
1066 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
1067                                          struct trace_event *event)
1068 {
1069         return trace_ctxwake_print(iter, "==>");
1070 }
1071
1072 static enum print_line_t trace_wake_print(struct trace_iterator *iter,
1073                                           int flags, struct trace_event *event)
1074 {
1075         return trace_ctxwake_print(iter, "  +");
1076 }
1077
1078 static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
1079 {
1080         struct ctx_switch_entry *field;
1081         int T;
1082
1083         trace_assign_type(field, iter->ent);
1084
1085         if (!S)
1086                 S = task_state_char(field->prev_state);
1087         T = task_state_char(field->next_state);
1088         if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
1089                               field->prev_pid,
1090                               field->prev_prio,
1091                               S,
1092                               field->next_cpu,
1093                               field->next_pid,
1094                               field->next_prio,
1095                               T))
1096                 return TRACE_TYPE_PARTIAL_LINE;
1097
1098         return TRACE_TYPE_HANDLED;
1099 }
1100
1101 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
1102                                        struct trace_event *event)
1103 {
1104         return trace_ctxwake_raw(iter, 0);
1105 }
1106
1107 static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
1108                                         struct trace_event *event)
1109 {
1110         return trace_ctxwake_raw(iter, '+');
1111 }
1112
1113
1114 static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
1115 {
1116         struct ctx_switch_entry *field;
1117         struct trace_seq *s = &iter->seq;
1118         int T;
1119
1120         trace_assign_type(field, iter->ent);
1121
1122         if (!S)
1123                 S = task_state_char(field->prev_state);
1124         T = task_state_char(field->next_state);
1125
1126         SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
1127         SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
1128         SEQ_PUT_HEX_FIELD_RET(s, S);
1129         SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
1130         SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
1131         SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
1132         SEQ_PUT_HEX_FIELD_RET(s, T);
1133
1134         return TRACE_TYPE_HANDLED;
1135 }
1136
1137 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
1138                                        struct trace_event *event)
1139 {
1140         return trace_ctxwake_hex(iter, 0);
1141 }
1142
1143 static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
1144                                         struct trace_event *event)
1145 {
1146         return trace_ctxwake_hex(iter, '+');
1147 }
1148
1149 static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
1150                                            int flags, struct trace_event *event)
1151 {
1152         struct ctx_switch_entry *field;
1153         struct trace_seq *s = &iter->seq;
1154
1155         trace_assign_type(field, iter->ent);
1156
1157         SEQ_PUT_FIELD_RET(s, field->prev_pid);
1158         SEQ_PUT_FIELD_RET(s, field->prev_prio);
1159         SEQ_PUT_FIELD_RET(s, field->prev_state);
1160         SEQ_PUT_FIELD_RET(s, field->next_pid);
1161         SEQ_PUT_FIELD_RET(s, field->next_prio);
1162         SEQ_PUT_FIELD_RET(s, field->next_state);
1163
1164         return TRACE_TYPE_HANDLED;
1165 }
1166
1167 static struct trace_event_functions trace_ctx_funcs = {
1168         .trace          = trace_ctx_print,
1169         .raw            = trace_ctx_raw,
1170         .hex            = trace_ctx_hex,
1171         .binary         = trace_ctxwake_bin,
1172 };
1173
1174 static struct trace_event trace_ctx_event = {
1175         .type           = TRACE_CTX,
1176         .funcs          = &trace_ctx_funcs,
1177 };
1178
1179 static struct trace_event_functions trace_wake_funcs = {
1180         .trace          = trace_wake_print,
1181         .raw            = trace_wake_raw,
1182         .hex            = trace_wake_hex,
1183         .binary         = trace_ctxwake_bin,
1184 };
1185
1186 static struct trace_event trace_wake_event = {
1187         .type           = TRACE_WAKE,
1188         .funcs          = &trace_wake_funcs,
1189 };
1190
1191 /* TRACE_STACK */
1192
1193 static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1194                                            int flags, struct trace_event *event)
1195 {
1196         struct stack_entry *field;
1197         struct trace_seq *s = &iter->seq;
1198         unsigned long *p;
1199         unsigned long *end;
1200
1201         trace_assign_type(field, iter->ent);
1202         end = (unsigned long *)((long)iter->ent + iter->ent_size);
1203
1204         if (!trace_seq_puts(s, "<stack trace>\n"))
1205                 goto partial;
1206
1207         for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
1208                 if (!trace_seq_puts(s, " => "))
1209                         goto partial;
1210
1211                 if (!seq_print_ip_sym(s, *p, flags))
1212                         goto partial;
1213                 if (!trace_seq_puts(s, "\n"))
1214                         goto partial;
1215         }
1216
1217         return TRACE_TYPE_HANDLED;
1218
1219  partial:
1220         return TRACE_TYPE_PARTIAL_LINE;
1221 }
1222
1223 static struct trace_event_functions trace_stack_funcs = {
1224         .trace          = trace_stack_print,
1225 };
1226
1227 static struct trace_event trace_stack_event = {
1228         .type           = TRACE_STACK,
1229         .funcs          = &trace_stack_funcs,
1230 };
1231
1232 /* TRACE_USER_STACK */
1233 static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1234                                                 int flags, struct trace_event *event)
1235 {
1236         struct userstack_entry *field;
1237         struct trace_seq *s = &iter->seq;
1238
1239         trace_assign_type(field, iter->ent);
1240
1241         if (!trace_seq_puts(s, "<user stack trace>\n"))
1242                 goto partial;
1243
1244         if (!seq_print_userip_objs(field, s, flags))
1245                 goto partial;
1246
1247         return TRACE_TYPE_HANDLED;
1248
1249  partial:
1250         return TRACE_TYPE_PARTIAL_LINE;
1251 }
1252
1253 static struct trace_event_functions trace_user_stack_funcs = {
1254         .trace          = trace_user_stack_print,
1255 };
1256
1257 static struct trace_event trace_user_stack_event = {
1258         .type           = TRACE_USER_STACK,
1259         .funcs          = &trace_user_stack_funcs,
1260 };
1261
1262 /* TRACE_BPUTS */
1263 static enum print_line_t
1264 trace_bputs_print(struct trace_iterator *iter, int flags,
1265                    struct trace_event *event)
1266 {
1267         struct trace_entry *entry = iter->ent;
1268         struct trace_seq *s = &iter->seq;
1269         struct bputs_entry *field;
1270
1271         trace_assign_type(field, entry);
1272
1273         if (!seq_print_ip_sym(s, field->ip, flags))
1274                 goto partial;
1275
1276         if (!trace_seq_puts(s, ": "))
1277                 goto partial;
1278
1279         if (!trace_seq_puts(s, field->str))
1280                 goto partial;
1281
1282         return TRACE_TYPE_HANDLED;
1283
1284  partial:
1285         return TRACE_TYPE_PARTIAL_LINE;
1286 }
1287
1288
1289 static enum print_line_t
1290 trace_bputs_raw(struct trace_iterator *iter, int flags,
1291                 struct trace_event *event)
1292 {
1293         struct bputs_entry *field;
1294         struct trace_seq *s = &iter->seq;
1295
1296         trace_assign_type(field, iter->ent);
1297
1298         if (!trace_seq_printf(s, ": %lx : ", field->ip))
1299                 goto partial;
1300
1301         if (!trace_seq_puts(s, field->str))
1302                 goto partial;
1303
1304         return TRACE_TYPE_HANDLED;
1305
1306  partial:
1307         return TRACE_TYPE_PARTIAL_LINE;
1308 }
1309
1310 static struct trace_event_functions trace_bputs_funcs = {
1311         .trace          = trace_bputs_print,
1312         .raw            = trace_bputs_raw,
1313 };
1314
1315 static struct trace_event trace_bputs_event = {
1316         .type           = TRACE_BPUTS,
1317         .funcs          = &trace_bputs_funcs,
1318 };
1319
1320 /* TRACE_BPRINT */
1321 static enum print_line_t
1322 trace_bprint_print(struct trace_iterator *iter, int flags,
1323                    struct trace_event *event)
1324 {
1325         struct trace_entry *entry = iter->ent;
1326         struct trace_seq *s = &iter->seq;
1327         struct bprint_entry *field;
1328
1329         trace_assign_type(field, entry);
1330
1331         if (!seq_print_ip_sym(s, field->ip, flags))
1332                 goto partial;
1333
1334         if (!trace_seq_puts(s, ": "))
1335                 goto partial;
1336
1337         if (!trace_seq_bprintf(s, field->fmt, field->buf))
1338                 goto partial;
1339
1340         return TRACE_TYPE_HANDLED;
1341
1342  partial:
1343         return TRACE_TYPE_PARTIAL_LINE;
1344 }
1345
1346
1347 static enum print_line_t
1348 trace_bprint_raw(struct trace_iterator *iter, int flags,
1349                  struct trace_event *event)
1350 {
1351         struct bprint_entry *field;
1352         struct trace_seq *s = &iter->seq;
1353
1354         trace_assign_type(field, iter->ent);
1355
1356         if (!trace_seq_printf(s, ": %lx : ", field->ip))
1357                 goto partial;
1358
1359         if (!trace_seq_bprintf(s, field->fmt, field->buf))
1360                 goto partial;
1361
1362         return TRACE_TYPE_HANDLED;
1363
1364  partial:
1365         return TRACE_TYPE_PARTIAL_LINE;
1366 }
1367
1368 static struct trace_event_functions trace_bprint_funcs = {
1369         .trace          = trace_bprint_print,
1370         .raw            = trace_bprint_raw,
1371 };
1372
1373 static struct trace_event trace_bprint_event = {
1374         .type           = TRACE_BPRINT,
1375         .funcs          = &trace_bprint_funcs,
1376 };
1377
1378 /* TRACE_PRINT */
1379 static enum print_line_t trace_print_print(struct trace_iterator *iter,
1380                                            int flags, struct trace_event *event)
1381 {
1382         struct print_entry *field;
1383         struct trace_seq *s = &iter->seq;
1384
1385         trace_assign_type(field, iter->ent);
1386
1387         if (!seq_print_ip_sym(s, field->ip, flags))
1388                 goto partial;
1389
1390         if (!trace_seq_printf(s, ": %s", field->buf))
1391                 goto partial;
1392
1393         return TRACE_TYPE_HANDLED;
1394
1395  partial:
1396         return TRACE_TYPE_PARTIAL_LINE;
1397 }
1398
1399 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1400                                          struct trace_event *event)
1401 {
1402         struct print_entry *field;
1403
1404         trace_assign_type(field, iter->ent);
1405
1406         if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
1407                 goto partial;
1408
1409         return TRACE_TYPE_HANDLED;
1410
1411  partial:
1412         return TRACE_TYPE_PARTIAL_LINE;
1413 }
1414
1415 static struct trace_event_functions trace_print_funcs = {
1416         .trace          = trace_print_print,
1417         .raw            = trace_print_raw,
1418 };
1419
1420 static struct trace_event trace_print_event = {
1421         .type           = TRACE_PRINT,
1422         .funcs          = &trace_print_funcs,
1423 };
1424
1425
1426 static struct trace_event *events[] __initdata = {
1427         &trace_fn_event,
1428         &trace_ctx_event,
1429         &trace_wake_event,
1430         &trace_stack_event,
1431         &trace_user_stack_event,
1432         &trace_bputs_event,
1433         &trace_bprint_event,
1434         &trace_print_event,
1435         NULL
1436 };
1437
1438 __init static int init_events(void)
1439 {
1440         struct trace_event *event;
1441         int i, ret;
1442
1443         for (i = 0; events[i]; i++) {
1444                 event = events[i];
1445
1446                 ret = register_ftrace_event(event);
1447                 if (!ret) {
1448                         printk(KERN_WARNING "event %d failed to register\n",
1449                                event->type);
1450                         WARN_ON_ONCE(1);
1451                 }
1452         }
1453
1454         return 0;
1455 }
1456 early_initcall(init_events);