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