kernel/trace/trace_functions_graph.c

   1 /*
   2  *
   3  * Function graph tracer.
   4  * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
   5  * Mostly borrowed from function tracer which
   6  * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
   7  *
   8  */
   9 #include <linux/debugfs.h>
  10 #include <linux/uaccess.h>
  11 #include <linux/ftrace.h>
  12 #include <linux/fs.h>
  13
  14 #include "trace.h"
  15 #include "trace_output.h"
  16
  17 struct fgraph_data {
  18         pid_t           last_pid;
  19         int             depth;
  20 };
  21
  22 #define TRACE_GRAPH_INDENT      2
  23
  24 /* Flag options */
  25 #define TRACE_GRAPH_PRINT_OVERRUN       0x1
  26 #define TRACE_GRAPH_PRINT_CPU           0x2
  27 #define TRACE_GRAPH_PRINT_OVERHEAD      0x4
  28 #define TRACE_GRAPH_PRINT_PROC          0x8
  29 #define TRACE_GRAPH_PRINT_DURATION      0x10
  30 #define TRACE_GRAPH_PRINT_ABS_TIME      0X20
  31
  32 static struct tracer_opt trace_opts[] = {
  33         /* Display overruns? (for self-debug purpose) */
  34         { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
  35         /* Display CPU ? */
  36         { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
  37         /* Display Overhead ? */
  38         { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
  39         /* Display proc name/pid */
  40         { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
  41         /* Display duration of execution */
  42         { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
  43         /* Display absolute time of an entry */
  44         { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
  45         { } /* Empty entry */
  46 };
  47
  48 static struct tracer_flags tracer_flags = {
  49         /* Don't display overruns and proc by default */
  50         .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
  51                TRACE_GRAPH_PRINT_DURATION,
  52         .opts = trace_opts
  53 };
  54
  55 /* pid on the last trace processed */
  56
  57
  58 /* Add a function return address to the trace stack on thread info.*/
  59 int
  60 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth)
  61 {
  62         unsigned long long calltime;
  63         int index;
  64
  65         if (!current->ret_stack)
  66                 return -EBUSY;
  67
  68         /* The return trace stack is full */
  69         if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
  70                 atomic_inc(&current->trace_overrun);
  71                 return -EBUSY;
  72         }
  73
  74         calltime = trace_clock_local();
  75
  76         index = ++current->curr_ret_stack;
  77         barrier();
  78         current->ret_stack[index].ret = ret;
  79         current->ret_stack[index].func = func;
  80         current->ret_stack[index].calltime = calltime;
  81         *depth = index;
  82
  83         return 0;
  84 }
  85
  86 /* Retrieve a function return address to the trace stack on thread info.*/
  87 void
  88 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
  89 {
  90         int index;
  91
  92         index = current->curr_ret_stack;
  93
  94         if (unlikely(index < 0)) {
  95                 ftrace_graph_stop();
  96                 WARN_ON(1);
  97                 /* Might as well panic, otherwise we have no where to go */
  98                 *ret = (unsigned long)panic;
  99                 return;
 100         }
 101
 102         *ret = current->ret_stack[index].ret;
 103         trace->func = current->ret_stack[index].func;
 104         trace->calltime = current->ret_stack[index].calltime;
 105         trace->overrun = atomic_read(&current->trace_overrun);
 106         trace->depth = index;
 107         barrier();
 108         current->curr_ret_stack--;
 109
 110 }
 111
 112 /*
 113  * Send the trace to the ring-buffer.
 114  * @return the original return address.
 115  */
 116 unsigned long ftrace_return_to_handler(void)
 117 {
 118         struct ftrace_graph_ret trace;
 119         unsigned long ret;
 120
 121         ftrace_pop_return_trace(&trace, &ret);
 122         trace.rettime = trace_clock_local();
 123         ftrace_graph_return(&trace);
 124
 125         if (unlikely(!ret)) {
 126                 ftrace_graph_stop();
 127                 WARN_ON(1);
 128                 /* Might as well panic. What else to do? */
 129                 ret = (unsigned long)panic;
 130         }
 131
 132         return ret;
 133 }
 134
 135 static int graph_trace_init(struct trace_array *tr)
 136 {
 137         int ret = register_ftrace_graph(&trace_graph_return,
 138                                         &trace_graph_entry);
 139         if (ret)
 140                 return ret;
 141         tracing_start_cmdline_record();
 142
 143         return 0;
 144 }
 145
 146 static void graph_trace_reset(struct trace_array *tr)
 147 {
 148         tracing_stop_cmdline_record();
 149         unregister_ftrace_graph();
 150 }
 151
 152 static inline int log10_cpu(int nb)
 153 {
 154         if (nb / 100)
 155                 return 3;
 156         if (nb / 10)
 157                 return 2;
 158         return 1;
 159 }
 160
 161 static enum print_line_t
 162 print_graph_cpu(struct trace_seq *s, int cpu)
 163 {
 164         int i;
 165         int ret;
 166         int log10_this = log10_cpu(cpu);
 167         int log10_all = log10_cpu(cpumask_weight(cpu_online_mask));
 168
 169
 170         /*
 171          * Start with a space character - to make it stand out
 172          * to the right a bit when trace output is pasted into
 173          * email:
 174          */
 175         ret = trace_seq_printf(s, " ");
 176
 177         /*
 178          * Tricky - we space the CPU field according to the max
 179          * number of online CPUs. On a 2-cpu system it would take
 180          * a maximum of 1 digit - on a 128 cpu system it would
 181          * take up to 3 digits:
 182          */
 183         for (i = 0; i < log10_all - log10_this; i++) {
 184                 ret = trace_seq_printf(s, " ");
 185                 if (!ret)
 186                         return TRACE_TYPE_PARTIAL_LINE;
 187         }
 188         ret = trace_seq_printf(s, "%d) ", cpu);
 189         if (!ret)
 190                 return TRACE_TYPE_PARTIAL_LINE;
 191
 192         return TRACE_TYPE_HANDLED;
 193 }
 194
 195 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 196
 197 static enum print_line_t
 198 print_graph_proc(struct trace_seq *s, pid_t pid)
 199 {
 200         char comm[TASK_COMM_LEN];
 201         /* sign + log10(MAX_INT) + '\0' */
 202         char pid_str[11];
 203         int spaces = 0;
 204         int ret;
 205         int len;
 206         int i;
 207
 208         trace_find_cmdline(pid, comm);
 209         comm[7] = '\0';
 210         sprintf(pid_str, "%d", pid);
 211
 212         /* 1 stands for the "-" character */
 213         len = strlen(comm) + strlen(pid_str) + 1;
 214
 215         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 216                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 217
 218         /* First spaces to align center */
 219         for (i = 0; i < spaces / 2; i++) {
 220                 ret = trace_seq_printf(s, " ");
 221                 if (!ret)
 222                         return TRACE_TYPE_PARTIAL_LINE;
 223         }
 224
 225         ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
 226         if (!ret)
 227                 return TRACE_TYPE_PARTIAL_LINE;
 228
 229         /* Last spaces to align center */
 230         for (i = 0; i < spaces - (spaces / 2); i++) {
 231                 ret = trace_seq_printf(s, " ");
 232                 if (!ret)
 233                         return TRACE_TYPE_PARTIAL_LINE;
 234         }
 235         return TRACE_TYPE_HANDLED;
 236 }
 237
 238
 239 /* If the pid changed since the last trace, output this event */
 240 static enum print_line_t
 241 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 242 {
 243         pid_t prev_pid;
 244         pid_t *last_pid;
 245         int ret;
 246
 247         if (!data)
 248                 return TRACE_TYPE_HANDLED;
 249
 250         last_pid = &(per_cpu_ptr(data, cpu)->last_pid);
 251
 252         if (*last_pid == pid)
 253                 return TRACE_TYPE_HANDLED;
 254
 255         prev_pid = *last_pid;
 256         *last_pid = pid;
 257
 258         if (prev_pid == -1)
 259                 return TRACE_TYPE_HANDLED;
 260 /*
 261  * Context-switch trace line:
 262
 263  ------------------------------------------
 264  | 1)  migration/0--1  =>  sshd-1755
 265  ------------------------------------------
 266
 267  */
 268         ret = trace_seq_printf(s,
 269                 " ------------------------------------------\n");
 270         if (!ret)
 271                 return TRACE_TYPE_PARTIAL_LINE;
 272
 273         ret = print_graph_cpu(s, cpu);
 274         if (ret == TRACE_TYPE_PARTIAL_LINE)
 275                 return TRACE_TYPE_PARTIAL_LINE;
 276
 277         ret = print_graph_proc(s, prev_pid);
 278         if (ret == TRACE_TYPE_PARTIAL_LINE)
 279                 return TRACE_TYPE_PARTIAL_LINE;
 280
 281         ret = trace_seq_printf(s, " => ");
 282         if (!ret)
 283                 return TRACE_TYPE_PARTIAL_LINE;
 284
 285         ret = print_graph_proc(s, pid);
 286         if (ret == TRACE_TYPE_PARTIAL_LINE)
 287                 return TRACE_TYPE_PARTIAL_LINE;
 288
 289         ret = trace_seq_printf(s,
 290                 "\n ------------------------------------------\n\n");
 291         if (!ret)
 292                 return TRACE_TYPE_PARTIAL_LINE;
 293
 294         return TRACE_TYPE_HANDLED;
 295 }
 296
 297 static struct ftrace_graph_ret_entry *
 298 get_return_for_leaf(struct trace_iterator *iter,
 299                 struct ftrace_graph_ent_entry *curr)
 300 {
 301         struct ring_buffer_iter *ring_iter;
 302         struct ring_buffer_event *event;
 303         struct ftrace_graph_ret_entry *next;
 304
 305         ring_iter = iter->buffer_iter[iter->cpu];
 306
 307         /* First peek to compare current entry and the next one */
 308         if (ring_iter)
 309                 event = ring_buffer_iter_peek(ring_iter, NULL);
 310         else {
 311         /* We need to consume the current entry to see the next one */
 312                 ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
 313                 event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
 314                                         NULL);
 315         }
 316
 317         if (!event)
 318                 return NULL;
 319
 320         next = ring_buffer_event_data(event);
 321
 322         if (next->ent.type != TRACE_GRAPH_RET)
 323                 return NULL;
 324
 325         if (curr->ent.pid != next->ent.pid ||
 326                         curr->graph_ent.func != next->ret.func)
 327                 return NULL;
 328
 329         /* this is a leaf, now advance the iterator */
 330         if (ring_iter)
 331                 ring_buffer_read(ring_iter, NULL);
 332
 333         return next;
 334 }
 335
 336 /* Signal a overhead of time execution to the output */
 337 static int
 338 print_graph_overhead(unsigned long long duration, struct trace_seq *s)
 339 {
 340         /* If duration disappear, we don't need anything */
 341         if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION))
 342                 return 1;
 343
 344         /* Non nested entry or return */
 345         if (duration == -1)
 346                 return trace_seq_printf(s, "  ");
 347
 348         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
 349                 /* Duration exceeded 100 msecs */
 350                 if (duration > 100000ULL)
 351                         return trace_seq_printf(s, "! ");
 352
 353                 /* Duration exceeded 10 msecs */
 354                 if (duration > 10000ULL)
 355                         return trace_seq_printf(s, "+ ");
 356         }
 357
 358         return trace_seq_printf(s, "  ");
 359 }
 360
 361 static int print_graph_abs_time(u64 t, struct trace_seq *s)
 362 {
 363         unsigned long usecs_rem;
 364
 365         usecs_rem = do_div(t, NSEC_PER_SEC);
 366         usecs_rem /= 1000;
 367
 368         return trace_seq_printf(s, "%5lu.%06lu |  ",
 369                         (unsigned long)t, usecs_rem);
 370 }
 371
 372 static enum print_line_t
 373 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 374                 enum trace_type type, int cpu, pid_t pid)
 375 {
 376         int ret;
 377         struct trace_seq *s = &iter->seq;
 378
 379         if (addr < (unsigned long)__irqentry_text_start ||
 380                 addr >= (unsigned long)__irqentry_text_end)
 381                 return TRACE_TYPE_UNHANDLED;
 382
 383         /* Absolute time */
 384         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 385                 ret = print_graph_abs_time(iter->ts, s);
 386                 if (!ret)
 387                         return TRACE_TYPE_PARTIAL_LINE;
 388         }
 389
 390         /* Cpu */
 391         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 392                 ret = print_graph_cpu(s, cpu);
 393                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 394                         return TRACE_TYPE_PARTIAL_LINE;
 395         }
 396         /* Proc */
 397         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 398                 ret = print_graph_proc(s, pid);
 399                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 400                         return TRACE_TYPE_PARTIAL_LINE;
 401                 ret = trace_seq_printf(s, " | ");
 402                 if (!ret)
 403                         return TRACE_TYPE_PARTIAL_LINE;
 404         }
 405
 406         /* No overhead */
 407         ret = print_graph_overhead(-1, s);
 408         if (!ret)
 409                 return TRACE_TYPE_PARTIAL_LINE;
 410
 411         if (type == TRACE_GRAPH_ENT)
 412                 ret = trace_seq_printf(s, "==========>");
 413         else
 414                 ret = trace_seq_printf(s, "<==========");
 415
 416         if (!ret)
 417                 return TRACE_TYPE_PARTIAL_LINE;
 418
 419         /* Don't close the duration column if haven't one */
 420         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 421                 trace_seq_printf(s, " |");
 422         ret = trace_seq_printf(s, "\n");
 423
 424         if (!ret)
 425                 return TRACE_TYPE_PARTIAL_LINE;
 426         return TRACE_TYPE_HANDLED;
 427 }
 428
 429 static enum print_line_t
 430 print_graph_duration(unsigned long long duration, struct trace_seq *s)
 431 {
 432         unsigned long nsecs_rem = do_div(duration, 1000);
 433         /* log10(ULONG_MAX) + '\0' */
 434         char msecs_str[21];
 435         char nsecs_str[5];
 436         int ret, len;
 437         int i;
 438
 439         sprintf(msecs_str, "%lu", (unsigned long) duration);
 440
 441         /* Print msecs */
 442         ret = trace_seq_printf(s, "%s", msecs_str);
 443         if (!ret)
 444                 return TRACE_TYPE_PARTIAL_LINE;
 445
 446         len = strlen(msecs_str);
 447
 448         /* Print nsecs (we don't want to exceed 7 numbers) */
 449         if (len < 7) {
 450                 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
 451                 ret = trace_seq_printf(s, ".%s", nsecs_str);
 452                 if (!ret)
 453                         return TRACE_TYPE_PARTIAL_LINE;
 454                 len += strlen(nsecs_str);
 455         }
 456
 457         ret = trace_seq_printf(s, " us ");
 458         if (!ret)
 459                 return TRACE_TYPE_PARTIAL_LINE;
 460
 461         /* Print remaining spaces to fit the row's width */
 462         for (i = len; i < 7; i++) {
 463                 ret = trace_seq_printf(s, " ");
 464                 if (!ret)
 465                         return TRACE_TYPE_PARTIAL_LINE;
 466         }
 467
 468         ret = trace_seq_printf(s, "|  ");
 469         if (!ret)
 470                 return TRACE_TYPE_PARTIAL_LINE;
 471         return TRACE_TYPE_HANDLED;
 472
 473 }
 474
 475 /* Case of a leaf function on its call entry */
 476 static enum print_line_t
 477 print_graph_entry_leaf(struct trace_iterator *iter,
 478                 struct ftrace_graph_ent_entry *entry,
 479                 struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s)
 480 {
 481         struct fgraph_data *data = iter->private;
 482         struct ftrace_graph_ret *graph_ret;
 483         struct ftrace_graph_ent *call;
 484         unsigned long long duration;
 485         int ret;
 486         int i;
 487
 488         graph_ret = &ret_entry->ret;
 489         call = &entry->graph_ent;
 490         duration = graph_ret->rettime - graph_ret->calltime;
 491
 492         if (data) {
 493                 int cpu = iter->cpu;
 494                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
 495
 496                 /*
 497                  * Comments display at + 1 to depth. Since
 498                  * this is a leaf function, keep the comments
 499                  * equal to this depth.
 500                  */
 501                 *depth = call->depth - 1;
 502         }
 503
 504         /* Overhead */
 505         ret = print_graph_overhead(duration, s);
 506         if (!ret)
 507                 return TRACE_TYPE_PARTIAL_LINE;
 508
 509         /* Duration */
 510         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 511                 ret = print_graph_duration(duration, s);
 512                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 513                         return TRACE_TYPE_PARTIAL_LINE;
 514         }
 515
 516         /* Function */
 517         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 518                 ret = trace_seq_printf(s, " ");
 519                 if (!ret)
 520                         return TRACE_TYPE_PARTIAL_LINE;
 521         }
 522
 523         ret = seq_print_ip_sym(s, call->func, 0);
 524         if (!ret)
 525                 return TRACE_TYPE_PARTIAL_LINE;
 526
 527         ret = trace_seq_printf(s, "();\n");
 528         if (!ret)
 529                 return TRACE_TYPE_PARTIAL_LINE;
 530
 531         return TRACE_TYPE_HANDLED;
 532 }
 533
 534 static enum print_line_t
 535 print_graph_entry_nested(struct trace_iterator *iter,
 536                          struct ftrace_graph_ent_entry *entry,
 537                          struct trace_seq *s, int cpu)
 538 {
 539         struct ftrace_graph_ent *call = &entry->graph_ent;
 540         struct fgraph_data *data = iter->private;
 541         int ret;
 542         int i;
 543
 544         if (data) {
 545                 int cpu = iter->cpu;
 546                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
 547
 548                 *depth = call->depth;
 549         }
 550
 551         /* No overhead */
 552         ret = print_graph_overhead(-1, s);
 553         if (!ret)
 554                 return TRACE_TYPE_PARTIAL_LINE;
 555
 556         /* No time */
 557         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 558                 ret = trace_seq_printf(s, "            |  ");
 559                 if (!ret)
 560                         return TRACE_TYPE_PARTIAL_LINE;
 561         }
 562
 563         /* Function */
 564         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 565                 ret = trace_seq_printf(s, " ");
 566                 if (!ret)
 567                         return TRACE_TYPE_PARTIAL_LINE;
 568         }
 569
 570         ret = seq_print_ip_sym(s, call->func, 0);
 571         if (!ret)
 572                 return TRACE_TYPE_PARTIAL_LINE;
 573
 574         ret = trace_seq_printf(s, "() {\n");
 575         if (!ret)
 576                 return TRACE_TYPE_PARTIAL_LINE;
 577
 578         /*
 579          * we already consumed the current entry to check the next one
 580          * and see if this is a leaf.
 581          */
 582         return TRACE_TYPE_NO_CONSUME;
 583 }
 584
 585 static enum print_line_t
 586 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 587                      int type, unsigned long addr)
 588 {
 589         struct fgraph_data *data = iter->private;
 590         struct trace_entry *ent = iter->ent;
 591         int cpu = iter->cpu;
 592         int ret;
 593
 594         /* Pid */
 595         if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
 596                 return TRACE_TYPE_PARTIAL_LINE;
 597
 598         if (type) {
 599                 /* Interrupt */
 600                 ret = print_graph_irq(iter, addr, type, cpu, ent->pid);
 601                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 602                         return TRACE_TYPE_PARTIAL_LINE;
 603         }
 604
 605         /* Absolute time */
 606         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 607                 ret = print_graph_abs_time(iter->ts, s);
 608                 if (!ret)
 609                         return TRACE_TYPE_PARTIAL_LINE;
 610         }
 611
 612         /* Cpu */
 613         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 614                 ret = print_graph_cpu(s, cpu);
 615                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 616                         return TRACE_TYPE_PARTIAL_LINE;
 617         }
 618
 619         /* Proc */
 620         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 621                 ret = print_graph_proc(s, ent->pid);
 622                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 623                         return TRACE_TYPE_PARTIAL_LINE;
 624
 625                 ret = trace_seq_printf(s, " | ");
 626                 if (!ret)
 627                         return TRACE_TYPE_PARTIAL_LINE;
 628         }
 629
 630         return 0;
 631 }
 632
 633 static enum print_line_t
 634 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 635                         struct trace_iterator *iter)
 636 {
 637         int cpu = iter->cpu;
 638         struct ftrace_graph_ent *call = &field->graph_ent;
 639         struct ftrace_graph_ret_entry *leaf_ret;
 640
 641         if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func))
 642                 return TRACE_TYPE_PARTIAL_LINE;
 643
 644         leaf_ret = get_return_for_leaf(iter, field);
 645         if (leaf_ret)
 646                 return print_graph_entry_leaf(iter, field, leaf_ret, s);
 647         else
 648                 return print_graph_entry_nested(iter, field, s, cpu);
 649
 650 }
 651
 652 static enum print_line_t
 653 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 654                    struct trace_entry *ent, struct trace_iterator *iter)
 655 {
 656         unsigned long long duration = trace->rettime - trace->calltime;
 657         struct fgraph_data *data = iter->private;
 658         pid_t pid = ent->pid;
 659         int cpu = iter->cpu;
 660         int ret;
 661         int i;
 662
 663         if (data) {
 664                 int cpu = iter->cpu;
 665                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
 666
 667                 /*
 668                  * Comments display at + 1 to depth. This is the
 669                  * return from a function, we now want the comments
 670                  * to display at the same level of the bracket.
 671                  */
 672                 *depth = trace->depth - 1;
 673         }
 674
 675         if (print_graph_prologue(iter, s, 0, 0))
 676                 return TRACE_TYPE_PARTIAL_LINE;
 677
 678         /* Overhead */
 679         ret = print_graph_overhead(duration, s);
 680         if (!ret)
 681                 return TRACE_TYPE_PARTIAL_LINE;
 682
 683         /* Duration */
 684         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 685                 ret = print_graph_duration(duration, s);
 686                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 687                         return TRACE_TYPE_PARTIAL_LINE;
 688         }
 689
 690         /* Closing brace */
 691         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
 692                 ret = trace_seq_printf(s, " ");
 693                 if (!ret)
 694                         return TRACE_TYPE_PARTIAL_LINE;
 695         }
 696
 697         ret = trace_seq_printf(s, "}\n");
 698         if (!ret)
 699                 return TRACE_TYPE_PARTIAL_LINE;
 700
 701         /* Overrun */
 702         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
 703                 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
 704                                         trace->overrun);
 705                 if (!ret)
 706                         return TRACE_TYPE_PARTIAL_LINE;
 707         }
 708
 709         ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid);
 710         if (ret == TRACE_TYPE_PARTIAL_LINE)
 711                 return TRACE_TYPE_PARTIAL_LINE;
 712
 713         return TRACE_TYPE_HANDLED;
 714 }
 715
 716 static enum print_line_t
 717 print_graph_comment(struct trace_seq *s,  struct trace_entry *ent,
 718                     struct trace_iterator *iter)
 719 {
 720         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
 721         struct fgraph_data *data = iter->private;
 722         struct trace_event *event;
 723         int depth = 0;
 724         int ret;
 725         int i;
 726
 727         if (data)
 728                 depth = per_cpu_ptr(data, iter->cpu)->depth;
 729
 730         if (print_graph_prologue(iter, s, 0, 0))
 731                 return TRACE_TYPE_PARTIAL_LINE;
 732
 733         /* No overhead */
 734         ret = print_graph_overhead(-1, s);
 735         if (!ret)
 736                 return TRACE_TYPE_PARTIAL_LINE;
 737
 738         /* No time */
 739         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 740                 ret = trace_seq_printf(s, "            |  ");
 741                 if (!ret)
 742                         return TRACE_TYPE_PARTIAL_LINE;
 743         }
 744
 745         /* Indentation */
 746         if (depth > 0)
 747                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
 748                         ret = trace_seq_printf(s, " ");
 749                         if (!ret)
 750                                 return TRACE_TYPE_PARTIAL_LINE;
 751                 }
 752
 753         /* The comment */
 754         ret = trace_seq_printf(s, "/* ");
 755         if (!ret)
 756                 return TRACE_TYPE_PARTIAL_LINE;
 757
 758         switch (iter->ent->type) {
 759         case TRACE_BPRINT:
 760                 ret = trace_print_bprintk_msg_only(iter);
 761                 if (ret != TRACE_TYPE_HANDLED)
 762                         return ret;
 763                 break;
 764         case TRACE_PRINT:
 765                 ret = trace_print_printk_msg_only(iter);
 766                 if (ret != TRACE_TYPE_HANDLED)
 767                         return ret;
 768                 break;
 769         default:
 770                 event = ftrace_find_event(ent->type);
 771                 if (!event)
 772                         return TRACE_TYPE_UNHANDLED;
 773
 774                 ret = event->trace(iter, sym_flags);
 775                 if (ret != TRACE_TYPE_HANDLED)
 776                         return ret;
 777         }
 778
 779         /* Strip ending newline */
 780         if (s->buffer[s->len - 1] == '\n') {
 781                 s->buffer[s->len - 1] = '\0';
 782                 s->len--;
 783         }
 784
 785         ret = trace_seq_printf(s, " */\n");
 786         if (!ret)
 787                 return TRACE_TYPE_PARTIAL_LINE;
 788
 789         return TRACE_TYPE_HANDLED;
 790 }
 791
 792
 793 enum print_line_t
 794 print_graph_function(struct trace_iterator *iter)
 795 {
 796         struct trace_entry *entry = iter->ent;
 797         struct trace_seq *s = &iter->seq;
 798
 799         switch (entry->type) {
 800         case TRACE_GRAPH_ENT: {
 801                 struct ftrace_graph_ent_entry *field;
 802                 trace_assign_type(field, entry);
 803                 return print_graph_entry(field, s, iter);
 804         }
 805         case TRACE_GRAPH_RET: {
 806                 struct ftrace_graph_ret_entry *field;
 807                 trace_assign_type(field, entry);
 808                 return print_graph_return(&field->ret, s, entry, iter);
 809         }
 810         default:
 811                 return print_graph_comment(s, entry, iter);
 812         }
 813
 814         return TRACE_TYPE_HANDLED;
 815 }
 816
 817 static void print_graph_headers(struct seq_file *s)
 818 {
 819         /* 1st line */
 820         seq_printf(s, "# ");
 821         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 822                 seq_printf(s, "     TIME       ");
 823         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 824                 seq_printf(s, "CPU");
 825         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 826                 seq_printf(s, "  TASK/PID      ");
 827         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 828                 seq_printf(s, "  DURATION   ");
 829         seq_printf(s, "               FUNCTION CALLS\n");
 830
 831         /* 2nd line */
 832         seq_printf(s, "# ");
 833         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 834                 seq_printf(s, "      |         ");
 835         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 836                 seq_printf(s, "|  ");
 837         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 838                 seq_printf(s, "  |    |        ");
 839         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 840                 seq_printf(s, "   |   |      ");
 841         seq_printf(s, "               |   |   |   |\n");
 842 }
 843
 844 static void graph_trace_open(struct trace_iterator *iter)
 845 {
 846         /* pid and depth on the last trace processed */
 847         struct fgraph_data *data = alloc_percpu(struct fgraph_data);
 848         int cpu;
 849
 850         if (!data)
 851                 pr_warning("function graph tracer: not enough memory\n");
 852         else
 853                 for_each_possible_cpu(cpu) {
 854                         pid_t *pid = &(per_cpu_ptr(data, cpu)->last_pid);
 855                         int *depth = &(per_cpu_ptr(data, cpu)->depth);
 856                         *pid = -1;
 857                         *depth = 0;
 858                 }
 859
 860         iter->private = data;
 861 }
 862
 863 static void graph_trace_close(struct trace_iterator *iter)
 864 {
 865         free_percpu(iter->private);
 866 }
 867
 868 static struct tracer graph_trace __read_mostly = {
 869         .name           = "function_graph",
 870         .open           = graph_trace_open,
 871         .close          = graph_trace_close,
 872         .wait_pipe      = poll_wait_pipe,
 873         .init           = graph_trace_init,
 874         .reset          = graph_trace_reset,
 875         .print_line     = print_graph_function,
 876         .print_header   = print_graph_headers,
 877         .flags          = &tracer_flags,
 878 #ifdef CONFIG_FTRACE_SELFTEST
 879         .selftest       = trace_selftest_startup_function_graph,
 880 #endif
 881 };
 882
 883 static __init int init_graph_trace(void)
 884 {
 885         return register_tracer(&graph_trace);
 886 }
 887
 888 device_initcall(init_graph_trace);