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_sem);
  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_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
  56enum 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
  72enum 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 */
 102int
 103trace_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}
 126EXPORT_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 */
 139int
 140trace_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}
 160EXPORT_SYMBOL_GPL(trace_seq_vprintf);
 161
 162int 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 */
 193int 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
 211int 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}
 225EXPORT_SYMBOL(trace_seq_putc);
 226
 227int 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
 243int 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
 265void *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
 283int 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
 311const char *
 312ftrace_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}
 347EXPORT_SYMBOL(ftrace_print_flags_seq);
 348
 349const char *
 350ftrace_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}
 372EXPORT_SYMBOL(ftrace_print_symbols_seq);
 373
 374#if BITS_PER_LONG == 32
 375const char *
 376ftrace_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}
 398EXPORT_SYMBOL(ftrace_print_symbols_seq_u64);
 399#endif
 400
 401const char *
 402ftrace_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}
 414EXPORT_SYMBOL(ftrace_print_hex_seq);
 415
 416int 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}
 440EXPORT_SYMBOL(ftrace_raw_output_prep);
 441
 442#ifdef CONFIG_KRETPROBES
 443static 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
 453static inline const char *kretprobed(const char *name)
 454{
 455        return name;
 456}
 457#endif /* CONFIG_KRETPROBES */
 458
 459static int
 460seq_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
 475static int
 476seq_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
 497int 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
 529int
 530seq_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
 576int
 577seq_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 */
 605int 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
 641static int
 642lat_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
 655static unsigned long preempt_mark_thresh_us = 100;
 656
 657static int
 658lat_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
 697int 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
 728int 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
 765static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
 766
 767static 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 */
 781struct 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
 796static LIST_HEAD(ftrace_event_list);
 797
 798static 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
 826void trace_event_read_lock(void)
 827{
 828        down_read(&trace_event_sem);
 829}
 830
 831void 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 */
 851int 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}
 915EXPORT_SYMBOL_GPL(register_ftrace_event);
 916
 917/*
 918 * Used by module code with the trace_event_sem held for write.
 919 */
 920int __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 */
 931int 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}
 939EXPORT_SYMBOL_GPL(unregister_ftrace_event);
 940
 941/*
 942 * Standard events
 943 */
 944
 945enum 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 */
 955static 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
 983static 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
 998static 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
1012static 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
1026static 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
1033static struct trace_event trace_fn_event = {
1034        .type           = TRACE_FN,
1035        .funcs          = &trace_fn_funcs,
1036};
1037
1038/* TRACE_CTX an TRACE_WAKE */
1039static 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
1066static 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
1072static 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
1078static 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
1101static 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
1107static 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
1114static 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
1137static 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
1143static 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
1149static 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
1167static 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
1174static struct trace_event trace_ctx_event = {
1175        .type           = TRACE_CTX,
1176        .funcs          = &trace_ctx_funcs,
1177};
1178
1179static 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
1186static struct trace_event trace_wake_event = {
1187        .type           = TRACE_WAKE,
1188        .funcs          = &trace_wake_funcs,
1189};
1190
1191/* TRACE_STACK */
1192
1193static 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
1223static struct trace_event_functions trace_stack_funcs = {
1224        .trace          = trace_stack_print,
1225};
1226
1227static struct trace_event trace_stack_event = {
1228        .type           = TRACE_STACK,
1229        .funcs          = &trace_stack_funcs,
1230};
1231
1232/* TRACE_USER_STACK */
1233static 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
1253static struct trace_event_functions trace_user_stack_funcs = {
1254        .trace          = trace_user_stack_print,
1255};
1256
1257static struct trace_event trace_user_stack_event = {
1258        .type           = TRACE_USER_STACK,
1259        .funcs          = &trace_user_stack_funcs,
1260};
1261
1262/* TRACE_BPUTS */
1263static enum print_line_t
1264trace_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
1289static enum print_line_t
1290trace_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
1310static struct trace_event_functions trace_bputs_funcs = {
1311        .trace          = trace_bputs_print,
1312        .raw            = trace_bputs_raw,
1313};
1314
1315static struct trace_event trace_bputs_event = {
1316        .type           = TRACE_BPUTS,
1317        .funcs          = &trace_bputs_funcs,
1318};
1319
1320/* TRACE_BPRINT */
1321static enum print_line_t
1322trace_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
1347static enum print_line_t
1348trace_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
1368static struct trace_event_functions trace_bprint_funcs = {
1369        .trace          = trace_bprint_print,
1370        .raw            = trace_bprint_raw,
1371};
1372
1373static struct trace_event trace_bprint_event = {
1374        .type           = TRACE_BPRINT,
1375        .funcs          = &trace_bprint_funcs,
1376};
1377
1378/* TRACE_PRINT */
1379static 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
1399static 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
1415static struct trace_event_functions trace_print_funcs = {
1416        .trace          = trace_print_print,
1417        .raw            = trace_print_raw,
1418};
1419
1420static struct trace_event trace_print_event = {
1421        .type           = TRACE_PRINT,
1422        .funcs          = &trace_print_funcs,
1423};
1424
1425
1426static 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}
1456early_initcall(init_events);
1457