linux/kernel/trace/trace_output.c
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   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
  17DECLARE_RWSEM(trace_event_mutex);
  18
  19static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
  20
  21static int next_event_type = __TRACE_LAST_TYPE + 1;
  22
  23int 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
  40enum 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
  56enum 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 */
  86int
  87trace_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}
 110EXPORT_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 */
 123int
 124trace_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}
 144EXPORT_SYMBOL_GPL(trace_seq_vprintf);
 145
 146int 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 */
 177int 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
 195int 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}
 209EXPORT_SYMBOL(trace_seq_putc);
 210
 211int 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
 227int 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
 249void *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
 267int 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
 295const char *
 296ftrace_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}
 331EXPORT_SYMBOL(ftrace_print_flags_seq);
 332
 333const char *
 334ftrace_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}
 356EXPORT_SYMBOL(ftrace_print_symbols_seq);
 357
 358#if BITS_PER_LONG == 32
 359const char *
 360ftrace_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}
 382EXPORT_SYMBOL(ftrace_print_symbols_seq_u64);
 383#endif
 384
 385const char *
 386ftrace_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}
 398EXPORT_SYMBOL(ftrace_print_hex_seq);
 399
 400#ifdef CONFIG_KRETPROBES
 401static 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
 411static inline const char *kretprobed(const char *name)
 412{
 413        return name;
 414}
 415#endif /* CONFIG_KRETPROBES */
 416
 417static int
 418seq_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
 433static int
 434seq_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
 455int 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
 487int
 488seq_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
 534int
 535seq_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 */
 563int 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
 599static int
 600lat_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
 613static unsigned long preempt_mark_thresh_us = 100;
 614
 615static int
 616lat_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
 655int 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
 686int 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
 723static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
 724
 725static 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 */
 739struct trace_event *ftrace_find_event(int type)
 740{
 741        struct trace_event *event;
 742        unsigned key;
 743
 744        key = type & (EVENT_HASHSIZE - 1);
 745
 746        hlist_for_each_entry(event, &event_hash[key], node) {
 747                if (event->type == type)
 748                        return event;
 749        }
 750
 751        return NULL;
 752}
 753
 754static LIST_HEAD(ftrace_event_list);
 755
 756static int trace_search_list(struct list_head **list)
 757{
 758        struct trace_event *e;
 759        int last = __TRACE_LAST_TYPE;
 760
 761        if (list_empty(&ftrace_event_list)) {
 762                *list = &ftrace_event_list;
 763                return last + 1;
 764        }
 765
 766        /*
 767         * We used up all possible max events,
 768         * lets see if somebody freed one.
 769         */
 770        list_for_each_entry(e, &ftrace_event_list, list) {
 771                if (e->type != last + 1)
 772                        break;
 773                last++;
 774        }
 775
 776        /* Did we used up all 65 thousand events??? */
 777        if ((last + 1) > FTRACE_MAX_EVENT)
 778                return 0;
 779
 780        *list = &e->list;
 781        return last + 1;
 782}
 783
 784void trace_event_read_lock(void)
 785{
 786        down_read(&trace_event_mutex);
 787}
 788
 789void trace_event_read_unlock(void)
 790{
 791        up_read(&trace_event_mutex);
 792}
 793
 794/**
 795 * register_ftrace_event - register output for an event type
 796 * @event: the event type to register
 797 *
 798 * Event types are stored in a hash and this hash is used to
 799 * find a way to print an event. If the @event->type is set
 800 * then it will use that type, otherwise it will assign a
 801 * type to use.
 802 *
 803 * If you assign your own type, please make sure it is added
 804 * to the trace_type enum in trace.h, to avoid collisions
 805 * with the dynamic types.
 806 *
 807 * Returns the event type number or zero on error.
 808 */
 809int register_ftrace_event(struct trace_event *event)
 810{
 811        unsigned key;
 812        int ret = 0;
 813
 814        down_write(&trace_event_mutex);
 815
 816        if (WARN_ON(!event))
 817                goto out;
 818
 819        if (WARN_ON(!event->funcs))
 820                goto out;
 821
 822        INIT_LIST_HEAD(&event->list);
 823
 824        if (!event->type) {
 825                struct list_head *list = NULL;
 826
 827                if (next_event_type > FTRACE_MAX_EVENT) {
 828
 829                        event->type = trace_search_list(&list);
 830                        if (!event->type)
 831                                goto out;
 832
 833                } else {
 834                        
 835                        event->type = next_event_type++;
 836                        list = &ftrace_event_list;
 837                }
 838
 839                if (WARN_ON(ftrace_find_event(event->type)))
 840                        goto out;
 841
 842                list_add_tail(&event->list, list);
 843
 844        } else if (event->type > __TRACE_LAST_TYPE) {
 845                printk(KERN_WARNING "Need to add type to trace.h\n");
 846                WARN_ON(1);
 847                goto out;
 848        } else {
 849                /* Is this event already used */
 850                if (ftrace_find_event(event->type))
 851                        goto out;
 852        }
 853
 854        if (event->funcs->trace == NULL)
 855                event->funcs->trace = trace_nop_print;
 856        if (event->funcs->raw == NULL)
 857                event->funcs->raw = trace_nop_print;
 858        if (event->funcs->hex == NULL)
 859                event->funcs->hex = trace_nop_print;
 860        if (event->funcs->binary == NULL)
 861                event->funcs->binary = trace_nop_print;
 862
 863        key = event->type & (EVENT_HASHSIZE - 1);
 864
 865        hlist_add_head(&event->node, &event_hash[key]);
 866
 867        ret = event->type;
 868 out:
 869        up_write(&trace_event_mutex);
 870
 871        return ret;
 872}
 873EXPORT_SYMBOL_GPL(register_ftrace_event);
 874
 875/*
 876 * Used by module code with the trace_event_mutex held for write.
 877 */
 878int __unregister_ftrace_event(struct trace_event *event)
 879{
 880        hlist_del(&event->node);
 881        list_del(&event->list);
 882        return 0;
 883}
 884
 885/**
 886 * unregister_ftrace_event - remove a no longer used event
 887 * @event: the event to remove
 888 */
 889int unregister_ftrace_event(struct trace_event *event)
 890{
 891        down_write(&trace_event_mutex);
 892        __unregister_ftrace_event(event);
 893        up_write(&trace_event_mutex);
 894
 895        return 0;
 896}
 897EXPORT_SYMBOL_GPL(unregister_ftrace_event);
 898
 899/*
 900 * Standard events
 901 */
 902
 903enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
 904                                  struct trace_event *event)
 905{
 906        if (!trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type))
 907                return TRACE_TYPE_PARTIAL_LINE;
 908
 909        return TRACE_TYPE_HANDLED;
 910}
 911
 912/* TRACE_FN */
 913static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
 914                                        struct trace_event *event)
 915{
 916        struct ftrace_entry *field;
 917        struct trace_seq *s = &iter->seq;
 918
 919        trace_assign_type(field, iter->ent);
 920
 921        if (!seq_print_ip_sym(s, field->ip, flags))
 922                goto partial;
 923
 924        if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
 925                if (!trace_seq_printf(s, " <-"))
 926                        goto partial;
 927                if (!seq_print_ip_sym(s,
 928                                      field->parent_ip,
 929                                      flags))
 930                        goto partial;
 931        }
 932        if (!trace_seq_printf(s, "\n"))
 933                goto partial;
 934
 935        return TRACE_TYPE_HANDLED;
 936
 937 partial:
 938        return TRACE_TYPE_PARTIAL_LINE;
 939}
 940
 941static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
 942                                      struct trace_event *event)
 943{
 944        struct ftrace_entry *field;
 945
 946        trace_assign_type(field, iter->ent);
 947
 948        if (!trace_seq_printf(&iter->seq, "%lx %lx\n",
 949                              field->ip,
 950                              field->parent_ip))
 951                return TRACE_TYPE_PARTIAL_LINE;
 952
 953        return TRACE_TYPE_HANDLED;
 954}
 955
 956static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
 957                                      struct trace_event *event)
 958{
 959        struct ftrace_entry *field;
 960        struct trace_seq *s = &iter->seq;
 961
 962        trace_assign_type(field, iter->ent);
 963
 964        SEQ_PUT_HEX_FIELD_RET(s, field->ip);
 965        SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
 966
 967        return TRACE_TYPE_HANDLED;
 968}
 969
 970static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
 971                                      struct trace_event *event)
 972{
 973        struct ftrace_entry *field;
 974        struct trace_seq *s = &iter->seq;
 975
 976        trace_assign_type(field, iter->ent);
 977
 978        SEQ_PUT_FIELD_RET(s, field->ip);
 979        SEQ_PUT_FIELD_RET(s, field->parent_ip);
 980
 981        return TRACE_TYPE_HANDLED;
 982}
 983
 984static struct trace_event_functions trace_fn_funcs = {
 985        .trace          = trace_fn_trace,
 986        .raw            = trace_fn_raw,
 987        .hex            = trace_fn_hex,
 988        .binary         = trace_fn_bin,
 989};
 990
 991static struct trace_event trace_fn_event = {
 992        .type           = TRACE_FN,
 993        .funcs          = &trace_fn_funcs,
 994};
 995
 996/* TRACE_CTX an TRACE_WAKE */
 997static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
 998                                             char *delim)
 999{
1000        struct ctx_switch_entry *field;
1001        char comm[TASK_COMM_LEN];
1002        int S, T;
1003
1004
1005        trace_assign_type(field, iter->ent);
1006
1007        T = task_state_char(field->next_state);
1008        S = task_state_char(field->prev_state);
1009        trace_find_cmdline(field->next_pid, comm);
1010        if (!trace_seq_printf(&iter->seq,
1011                              " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
1012                              field->prev_pid,
1013                              field->prev_prio,
1014                              S, delim,
1015                              field->next_cpu,
1016                              field->next_pid,
1017                              field->next_prio,
1018                              T, comm))
1019                return TRACE_TYPE_PARTIAL_LINE;
1020
1021        return TRACE_TYPE_HANDLED;
1022}
1023
1024static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
1025                                         struct trace_event *event)
1026{
1027        return trace_ctxwake_print(iter, "==>");
1028}
1029
1030static enum print_line_t trace_wake_print(struct trace_iterator *iter,
1031                                          int flags, struct trace_event *event)
1032{
1033        return trace_ctxwake_print(iter, "  +");
1034}
1035
1036static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
1037{
1038        struct ctx_switch_entry *field;
1039        int T;
1040
1041        trace_assign_type(field, iter->ent);
1042
1043        if (!S)
1044                S = task_state_char(field->prev_state);
1045        T = task_state_char(field->next_state);
1046        if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
1047                              field->prev_pid,
1048                              field->prev_prio,
1049                              S,
1050                              field->next_cpu,
1051                              field->next_pid,
1052                              field->next_prio,
1053                              T))
1054                return TRACE_TYPE_PARTIAL_LINE;
1055
1056        return TRACE_TYPE_HANDLED;
1057}
1058
1059static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
1060                                       struct trace_event *event)
1061{
1062        return trace_ctxwake_raw(iter, 0);
1063}
1064
1065static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
1066                                        struct trace_event *event)
1067{
1068        return trace_ctxwake_raw(iter, '+');
1069}
1070
1071
1072static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
1073{
1074        struct ctx_switch_entry *field;
1075        struct trace_seq *s = &iter->seq;
1076        int T;
1077
1078        trace_assign_type(field, iter->ent);
1079
1080        if (!S)
1081                S = task_state_char(field->prev_state);
1082        T = task_state_char(field->next_state);
1083
1084        SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
1085        SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
1086        SEQ_PUT_HEX_FIELD_RET(s, S);
1087        SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
1088        SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
1089        SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
1090        SEQ_PUT_HEX_FIELD_RET(s, T);
1091
1092        return TRACE_TYPE_HANDLED;
1093}
1094
1095static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
1096                                       struct trace_event *event)
1097{
1098        return trace_ctxwake_hex(iter, 0);
1099}
1100
1101static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
1102                                        struct trace_event *event)
1103{
1104        return trace_ctxwake_hex(iter, '+');
1105}
1106
1107static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
1108                                           int flags, struct trace_event *event)
1109{
1110        struct ctx_switch_entry *field;
1111        struct trace_seq *s = &iter->seq;
1112
1113        trace_assign_type(field, iter->ent);
1114
1115        SEQ_PUT_FIELD_RET(s, field->prev_pid);
1116        SEQ_PUT_FIELD_RET(s, field->prev_prio);
1117        SEQ_PUT_FIELD_RET(s, field->prev_state);
1118        SEQ_PUT_FIELD_RET(s, field->next_pid);
1119        SEQ_PUT_FIELD_RET(s, field->next_prio);
1120        SEQ_PUT_FIELD_RET(s, field->next_state);
1121
1122        return TRACE_TYPE_HANDLED;
1123}
1124
1125static struct trace_event_functions trace_ctx_funcs = {
1126        .trace          = trace_ctx_print,
1127        .raw            = trace_ctx_raw,
1128        .hex            = trace_ctx_hex,
1129        .binary         = trace_ctxwake_bin,
1130};
1131
1132static struct trace_event trace_ctx_event = {
1133        .type           = TRACE_CTX,
1134        .funcs          = &trace_ctx_funcs,
1135};
1136
1137static struct trace_event_functions trace_wake_funcs = {
1138        .trace          = trace_wake_print,
1139        .raw            = trace_wake_raw,
1140        .hex            = trace_wake_hex,
1141        .binary         = trace_ctxwake_bin,
1142};
1143
1144static struct trace_event trace_wake_event = {
1145        .type           = TRACE_WAKE,
1146        .funcs          = &trace_wake_funcs,
1147};
1148
1149/* TRACE_STACK */
1150
1151static enum print_line_t trace_stack_print(struct trace_iterator *iter,
1152                                           int flags, struct trace_event *event)
1153{
1154        struct stack_entry *field;
1155        struct trace_seq *s = &iter->seq;
1156        unsigned long *p;
1157        unsigned long *end;
1158
1159        trace_assign_type(field, iter->ent);
1160        end = (unsigned long *)((long)iter->ent + iter->ent_size);
1161
1162        if (!trace_seq_puts(s, "<stack trace>\n"))
1163                goto partial;
1164
1165        for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
1166                if (!trace_seq_puts(s, " => "))
1167                        goto partial;
1168
1169                if (!seq_print_ip_sym(s, *p, flags))
1170                        goto partial;
1171                if (!trace_seq_puts(s, "\n"))
1172                        goto partial;
1173        }
1174
1175        return TRACE_TYPE_HANDLED;
1176
1177 partial:
1178        return TRACE_TYPE_PARTIAL_LINE;
1179}
1180
1181static struct trace_event_functions trace_stack_funcs = {
1182        .trace          = trace_stack_print,
1183};
1184
1185static struct trace_event trace_stack_event = {
1186        .type           = TRACE_STACK,
1187        .funcs          = &trace_stack_funcs,
1188};
1189
1190/* TRACE_USER_STACK */
1191static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
1192                                                int flags, struct trace_event *event)
1193{
1194        struct userstack_entry *field;
1195        struct trace_seq *s = &iter->seq;
1196
1197        trace_assign_type(field, iter->ent);
1198
1199        if (!trace_seq_puts(s, "<user stack trace>\n"))
1200                goto partial;
1201
1202        if (!seq_print_userip_objs(field, s, flags))
1203                goto partial;
1204
1205        return TRACE_TYPE_HANDLED;
1206
1207 partial:
1208        return TRACE_TYPE_PARTIAL_LINE;
1209}
1210
1211static struct trace_event_functions trace_user_stack_funcs = {
1212        .trace          = trace_user_stack_print,
1213};
1214
1215static struct trace_event trace_user_stack_event = {
1216        .type           = TRACE_USER_STACK,
1217        .funcs          = &trace_user_stack_funcs,
1218};
1219
1220/* TRACE_BPRINT */
1221static enum print_line_t
1222trace_bprint_print(struct trace_iterator *iter, int flags,
1223                   struct trace_event *event)
1224{
1225        struct trace_entry *entry = iter->ent;
1226        struct trace_seq *s = &iter->seq;
1227        struct bprint_entry *field;
1228
1229        trace_assign_type(field, entry);
1230
1231        if (!seq_print_ip_sym(s, field->ip, flags))
1232                goto partial;
1233
1234        if (!trace_seq_puts(s, ": "))
1235                goto partial;
1236
1237        if (!trace_seq_bprintf(s, field->fmt, field->buf))
1238                goto partial;
1239
1240        return TRACE_TYPE_HANDLED;
1241
1242 partial:
1243        return TRACE_TYPE_PARTIAL_LINE;
1244}
1245
1246
1247static enum print_line_t
1248trace_bprint_raw(struct trace_iterator *iter, int flags,
1249                 struct trace_event *event)
1250{
1251        struct bprint_entry *field;
1252        struct trace_seq *s = &iter->seq;
1253
1254        trace_assign_type(field, iter->ent);
1255
1256        if (!trace_seq_printf(s, ": %lx : ", field->ip))
1257                goto partial;
1258
1259        if (!trace_seq_bprintf(s, field->fmt, field->buf))
1260                goto partial;
1261
1262        return TRACE_TYPE_HANDLED;
1263
1264 partial:
1265        return TRACE_TYPE_PARTIAL_LINE;
1266}
1267
1268static struct trace_event_functions trace_bprint_funcs = {
1269        .trace          = trace_bprint_print,
1270        .raw            = trace_bprint_raw,
1271};
1272
1273static struct trace_event trace_bprint_event = {
1274        .type           = TRACE_BPRINT,
1275        .funcs          = &trace_bprint_funcs,
1276};
1277
1278/* TRACE_PRINT */
1279static enum print_line_t trace_print_print(struct trace_iterator *iter,
1280                                           int flags, struct trace_event *event)
1281{
1282        struct print_entry *field;
1283        struct trace_seq *s = &iter->seq;
1284
1285        trace_assign_type(field, iter->ent);
1286
1287        if (!seq_print_ip_sym(s, field->ip, flags))
1288                goto partial;
1289
1290        if (!trace_seq_printf(s, ": %s", field->buf))
1291                goto partial;
1292
1293        return TRACE_TYPE_HANDLED;
1294
1295 partial:
1296        return TRACE_TYPE_PARTIAL_LINE;
1297}
1298
1299static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
1300                                         struct trace_event *event)
1301{
1302        struct print_entry *field;
1303
1304        trace_assign_type(field, iter->ent);
1305
1306        if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
1307                goto partial;
1308
1309        return TRACE_TYPE_HANDLED;
1310
1311 partial:
1312        return TRACE_TYPE_PARTIAL_LINE;
1313}
1314
1315static struct trace_event_functions trace_print_funcs = {
1316        .trace          = trace_print_print,
1317        .raw            = trace_print_raw,
1318};
1319
1320static struct trace_event trace_print_event = {
1321        .type           = TRACE_PRINT,
1322        .funcs          = &trace_print_funcs,
1323};
1324
1325
1326static struct trace_event *events[] __initdata = {
1327        &trace_fn_event,
1328        &trace_ctx_event,
1329        &trace_wake_event,
1330        &trace_stack_event,
1331        &trace_user_stack_event,
1332        &trace_bprint_event,
1333        &trace_print_event,
1334        NULL
1335};
1336
1337__init static int init_events(void)
1338{
1339        struct trace_event *event;
1340        int i, ret;
1341
1342        for (i = 0; events[i]; i++) {
1343                event = events[i];
1344
1345                ret = register_ftrace_event(event);
1346                if (!ret) {
1347                        printk(KERN_WARNING "event %d failed to register\n",
1348                               event->type);
1349                        WARN_ON_ONCE(1);
1350                }
1351        }
1352
1353        return 0;
1354}
1355early_initcall(init_events);
1356
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