SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 static struct trace_array *graph_array;
  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                          unsigned long frame_pointer)
  62 {
  63         unsigned long long calltime;
  64         int index;
  65
  66         if (!current->ret_stack)
  67                 return -EBUSY;
  68
  69         /*
  70          * We must make sure the ret_stack is tested before we read
  71          * anything else.
  72          */
  73         smp_rmb();
  74
  75         /* The return trace stack is full */
  76         if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
  77                 atomic_inc(&current->trace_overrun);
  78                 return -EBUSY;
  79         }
  80
  81         calltime = trace_clock_local();
  82
  83         index = ++current->curr_ret_stack;
  84         barrier();
  85         current->ret_stack[index].ret = ret;
  86         current->ret_stack[index].func = func;
  87         current->ret_stack[index].calltime = calltime;
  88         current->ret_stack[index].subtime = 0;
  89         current->ret_stack[index].fp = frame_pointer;
  90         *depth = index;
  91
  92         return 0;
  93 }
  94
  95 /* Retrieve a function return address to the trace stack on thread info.*/
  96 static void
  97 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
  98                         unsigned long frame_pointer)
  99 {
 100         int index;
 101
 102         index = current->curr_ret_stack;
 103
 104         if (unlikely(index < 0)) {
 105                 ftrace_graph_stop();
 106                 WARN_ON(1);
 107                 /* Might as well panic, otherwise we have no where to go */
 108                 *ret = (unsigned long)panic;
 109                 return;
 110         }
 111
 112 #ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
 113         /*
 114          * The arch may choose to record the frame pointer used
 115          * and check it here to make sure that it is what we expect it
 116          * to be. If gcc does not set the place holder of the return
 117          * address in the frame pointer, and does a copy instead, then
 118          * the function graph trace will fail. This test detects this
 119          * case.
 120          *
 121          * Currently, x86_32 with optimize for size (-Os) makes the latest
 122          * gcc do the above.
 123          */
 124         if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
 125                 ftrace_graph_stop();
 126                 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
 127                      "  from func %pF return to %lx\n",
 128                      current->ret_stack[index].fp,
 129                      frame_pointer,
 130                      (void *)current->ret_stack[index].func,
 131                      current->ret_stack[index].ret);
 132                 *ret = (unsigned long)panic;
 133                 return;
 134         }
 135 #endif
 136
 137         *ret = current->ret_stack[index].ret;
 138         trace->func = current->ret_stack[index].func;
 139         trace->calltime = current->ret_stack[index].calltime;
 140         trace->overrun = atomic_read(&current->trace_overrun);
 141         trace->depth = index;
 142 }
 143
 144 /*
 145  * Send the trace to the ring-buffer.
 146  * @return the original return address.
 147  */
 148 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 149 {
 150         struct ftrace_graph_ret trace;
 151         unsigned long ret;
 152
 153         ftrace_pop_return_trace(&trace, &ret, frame_pointer);
 154         trace.rettime = trace_clock_local();
 155         ftrace_graph_return(&trace);
 156         barrier();
 157         current->curr_ret_stack--;
 158
 159         if (unlikely(!ret)) {
 160                 ftrace_graph_stop();
 161                 WARN_ON(1);
 162                 /* Might as well panic. What else to do? */
 163                 ret = (unsigned long)panic;
 164         }
 165
 166         return ret;
 167 }
 168
 169 static int __trace_graph_entry(struct trace_array *tr,
 170                                 struct ftrace_graph_ent *trace,
 171                                 unsigned long flags,
 172                                 int pc)
 173 {
 174         struct ftrace_event_call *call = &event_funcgraph_entry;
 175         struct ring_buffer_event *event;
 176         struct ftrace_graph_ent_entry *entry;
 177
 178         if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
 179                 return 0;
 180
 181         event = trace_buffer_lock_reserve(tr, TRACE_GRAPH_ENT,
 182                                           sizeof(*entry), flags, pc);
 183         if (!event)
 184                 return 0;
 185         entry   = ring_buffer_event_data(event);
 186         entry->graph_ent                        = *trace;
 187         if (!filter_current_check_discard(call, entry, event))
 188                 ring_buffer_unlock_commit(tr->buffer, event);
 189
 190         return 1;
 191 }
 192
 193 int trace_graph_entry(struct ftrace_graph_ent *trace)
 194 {
 195         struct trace_array *tr = graph_array;
 196         struct trace_array_cpu *data;
 197         unsigned long flags;
 198         long disabled;
 199         int ret;
 200         int cpu;
 201         int pc;
 202
 203         if (unlikely(!tr))
 204                 return 0;
 205
 206         if (!ftrace_trace_task(current))
 207                 return 0;
 208
 209         if (!ftrace_graph_addr(trace->func))
 210                 return 0;
 211
 212         local_irq_save(flags);
 213         cpu = raw_smp_processor_id();
 214         data = tr->data[cpu];
 215         disabled = atomic_inc_return(&data->disabled);
 216         if (likely(disabled == 1)) {
 217                 pc = preempt_count();
 218                 ret = __trace_graph_entry(tr, trace, flags, pc);
 219         } else {
 220                 ret = 0;
 221         }
 222         /* Only do the atomic if it is not already set */
 223         if (!test_tsk_trace_graph(current))
 224                 set_tsk_trace_graph(current);
 225
 226         atomic_dec(&data->disabled);
 227         local_irq_restore(flags);
 228
 229         return ret;
 230 }
 231
 232 static void __trace_graph_return(struct trace_array *tr,
 233                                 struct ftrace_graph_ret *trace,
 234                                 unsigned long flags,
 235                                 int pc)
 236 {
 237         struct ftrace_event_call *call = &event_funcgraph_exit;
 238         struct ring_buffer_event *event;
 239         struct ftrace_graph_ret_entry *entry;
 240
 241         if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
 242                 return;
 243
 244         event = trace_buffer_lock_reserve(tr, TRACE_GRAPH_RET,
 245                                           sizeof(*entry), flags, pc);
 246         if (!event)
 247                 return;
 248         entry   = ring_buffer_event_data(event);
 249         entry->ret                              = *trace;
 250         if (!filter_current_check_discard(call, entry, event))
 251                 ring_buffer_unlock_commit(tr->buffer, event);
 252 }
 253
 254 void trace_graph_return(struct ftrace_graph_ret *trace)
 255 {
 256         struct trace_array *tr = graph_array;
 257         struct trace_array_cpu *data;
 258         unsigned long flags;
 259         long disabled;
 260         int cpu;
 261         int pc;
 262
 263         local_irq_save(flags);
 264         cpu = raw_smp_processor_id();
 265         data = tr->data[cpu];
 266         disabled = atomic_inc_return(&data->disabled);
 267         if (likely(disabled == 1)) {
 268                 pc = preempt_count();
 269                 __trace_graph_return(tr, trace, flags, pc);
 270         }
 271         if (!trace->depth)
 272                 clear_tsk_trace_graph(current);
 273         atomic_dec(&data->disabled);
 274         local_irq_restore(flags);
 275 }
 276
 277 static int graph_trace_init(struct trace_array *tr)
 278 {
 279         int ret;
 280
 281         graph_array = tr;
 282         ret = register_ftrace_graph(&trace_graph_return,
 283                                     &trace_graph_entry);
 284         if (ret)
 285                 return ret;
 286         tracing_start_cmdline_record();
 287
 288         return 0;
 289 }
 290
 291 void set_graph_array(struct trace_array *tr)
 292 {
 293         graph_array = tr;
 294 }
 295
 296 static void graph_trace_reset(struct trace_array *tr)
 297 {
 298         tracing_stop_cmdline_record();
 299         unregister_ftrace_graph();
 300 }
 301
 302 static int max_bytes_for_cpu;
 303
 304 static enum print_line_t
 305 print_graph_cpu(struct trace_seq *s, int cpu)
 306 {
 307         int ret;
 308
 309         /*
 310          * Start with a space character - to make it stand out
 311          * to the right a bit when trace output is pasted into
 312          * email:
 313          */
 314         ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 315         if (!ret)
 316                 return TRACE_TYPE_PARTIAL_LINE;
 317
 318         return TRACE_TYPE_HANDLED;
 319 }
 320
 321 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 322
 323 static enum print_line_t
 324 print_graph_proc(struct trace_seq *s, pid_t pid)
 325 {
 326         char comm[TASK_COMM_LEN];
 327         /* sign + log10(MAX_INT) + '\0' */
 328         char pid_str[11];
 329         int spaces = 0;
 330         int ret;
 331         int len;
 332         int i;
 333
 334         trace_find_cmdline(pid, comm);
 335         comm[7] = '\0';
 336         sprintf(pid_str, "%d", pid);
 337
 338         /* 1 stands for the "-" character */
 339         len = strlen(comm) + strlen(pid_str) + 1;
 340
 341         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 342                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 343
 344         /* First spaces to align center */
 345         for (i = 0; i < spaces / 2; i++) {
 346                 ret = trace_seq_printf(s, " ");
 347                 if (!ret)
 348                         return TRACE_TYPE_PARTIAL_LINE;
 349         }
 350
 351         ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
 352         if (!ret)
 353                 return TRACE_TYPE_PARTIAL_LINE;
 354
 355         /* Last spaces to align center */
 356         for (i = 0; i < spaces - (spaces / 2); i++) {
 357                 ret = trace_seq_printf(s, " ");
 358                 if (!ret)
 359                         return TRACE_TYPE_PARTIAL_LINE;
 360         }
 361         return TRACE_TYPE_HANDLED;
 362 }
 363
 364
 365 /* If the pid changed since the last trace, output this event */
 366 static enum print_line_t
 367 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 368 {
 369         pid_t prev_pid;
 370         pid_t *last_pid;
 371         int ret;
 372
 373         if (!data)
 374                 return TRACE_TYPE_HANDLED;
 375
 376         last_pid = &(per_cpu_ptr(data, cpu)->last_pid);
 377
 378         if (*last_pid == pid)
 379                 return TRACE_TYPE_HANDLED;
 380
 381         prev_pid = *last_pid;
 382         *last_pid = pid;
 383
 384         if (prev_pid == -1)
 385                 return TRACE_TYPE_HANDLED;
 386 /*
 387  * Context-switch trace line:
 388
 389  ------------------------------------------
 390  | 1)  migration/0--1  =>  sshd-1755
 391  ------------------------------------------
 392
 393  */
 394         ret = trace_seq_printf(s,
 395                 " ------------------------------------------\n");
 396         if (!ret)
 397                 return TRACE_TYPE_PARTIAL_LINE;
 398
 399         ret = print_graph_cpu(s, cpu);
 400         if (ret == TRACE_TYPE_PARTIAL_LINE)
 401                 return TRACE_TYPE_PARTIAL_LINE;
 402
 403         ret = print_graph_proc(s, prev_pid);
 404         if (ret == TRACE_TYPE_PARTIAL_LINE)
 405                 return TRACE_TYPE_PARTIAL_LINE;
 406
 407         ret = trace_seq_printf(s, " => ");
 408         if (!ret)
 409                 return TRACE_TYPE_PARTIAL_LINE;
 410
 411         ret = print_graph_proc(s, pid);
 412         if (ret == TRACE_TYPE_PARTIAL_LINE)
 413                 return TRACE_TYPE_PARTIAL_LINE;
 414
 415         ret = trace_seq_printf(s,
 416                 "\n ------------------------------------------\n\n");
 417         if (!ret)
 418                 return TRACE_TYPE_PARTIAL_LINE;
 419
 420         return TRACE_TYPE_HANDLED;
 421 }
 422
 423 static struct ftrace_graph_ret_entry *
 424 get_return_for_leaf(struct trace_iterator *iter,
 425                 struct ftrace_graph_ent_entry *curr)
 426 {
 427         struct ring_buffer_iter *ring_iter;
 428         struct ring_buffer_event *event;
 429         struct ftrace_graph_ret_entry *next;
 430
 431         ring_iter = iter->buffer_iter[iter->cpu];
 432
 433         /* First peek to compare current entry and the next one */
 434         if (ring_iter)
 435                 event = ring_buffer_iter_peek(ring_iter, NULL);
 436         else {
 437         /* We need to consume the current entry to see the next one */
 438                 ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
 439                 event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
 440                                         NULL);
 441         }
 442
 443         if (!event)
 444                 return NULL;
 445
 446         next = ring_buffer_event_data(event);
 447
 448         if (next->ent.type != TRACE_GRAPH_RET)
 449                 return NULL;
 450
 451         if (curr->ent.pid != next->ent.pid ||
 452                         curr->graph_ent.func != next->ret.func)
 453                 return NULL;
 454
 455         /* this is a leaf, now advance the iterator */
 456         if (ring_iter)
 457                 ring_buffer_read(ring_iter, NULL);
 458
 459         return next;
 460 }
 461
 462 /* Signal a overhead of time execution to the output */
 463 static int
 464 print_graph_overhead(unsigned long long duration, struct trace_seq *s)
 465 {
 466         /* If duration disappear, we don't need anything */
 467         if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION))
 468                 return 1;
 469
 470         /* Non nested entry or return */
 471         if (duration == -1)
 472                 return trace_seq_printf(s, "  ");
 473
 474         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
 475                 /* Duration exceeded 100 msecs */
 476                 if (duration > 100000ULL)
 477                         return trace_seq_printf(s, "! ");
 478
 479                 /* Duration exceeded 10 msecs */
 480                 if (duration > 10000ULL)
 481                         return trace_seq_printf(s, "+ ");
 482         }
 483
 484         return trace_seq_printf(s, "  ");
 485 }
 486
 487 static int print_graph_abs_time(u64 t, struct trace_seq *s)
 488 {
 489         unsigned long usecs_rem;
 490
 491         usecs_rem = do_div(t, NSEC_PER_SEC);
 492         usecs_rem /= 1000;
 493
 494         return trace_seq_printf(s, "%5lu.%06lu |  ",
 495                         (unsigned long)t, usecs_rem);
 496 }
 497
 498 static enum print_line_t
 499 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 500                 enum trace_type type, int cpu, pid_t pid)
 501 {
 502         int ret;
 503         struct trace_seq *s = &iter->seq;
 504
 505         if (addr < (unsigned long)__irqentry_text_start ||
 506                 addr >= (unsigned long)__irqentry_text_end)
 507                 return TRACE_TYPE_UNHANDLED;
 508
 509         /* Absolute time */
 510         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 511                 ret = print_graph_abs_time(iter->ts, s);
 512                 if (!ret)
 513                         return TRACE_TYPE_PARTIAL_LINE;
 514         }
 515
 516         /* Cpu */
 517         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 518                 ret = print_graph_cpu(s, cpu);
 519                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 520                         return TRACE_TYPE_PARTIAL_LINE;
 521         }
 522         /* Proc */
 523         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 524                 ret = print_graph_proc(s, pid);
 525                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 526                         return TRACE_TYPE_PARTIAL_LINE;
 527                 ret = trace_seq_printf(s, " | ");
 528                 if (!ret)
 529                         return TRACE_TYPE_PARTIAL_LINE;
 530         }
 531
 532         /* No overhead */
 533         ret = print_graph_overhead(-1, s);
 534         if (!ret)
 535                 return TRACE_TYPE_PARTIAL_LINE;
 536
 537         if (type == TRACE_GRAPH_ENT)
 538                 ret = trace_seq_printf(s, "==========>");
 539         else
 540                 ret = trace_seq_printf(s, "<==========");
 541
 542         if (!ret)
 543                 return TRACE_TYPE_PARTIAL_LINE;
 544
 545         /* Don't close the duration column if haven't one */
 546         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 547                 trace_seq_printf(s, " |");
 548         ret = trace_seq_printf(s, "\n");
 549
 550         if (!ret)
 551                 return TRACE_TYPE_PARTIAL_LINE;
 552         return TRACE_TYPE_HANDLED;
 553 }
 554
 555 enum print_line_t
 556 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 557 {
 558         unsigned long nsecs_rem = do_div(duration, 1000);
 559         /* log10(ULONG_MAX) + '\0' */
 560         char msecs_str[21];
 561         char nsecs_str[5];
 562         int ret, len;
 563         int i;
 564
 565         sprintf(msecs_str, "%lu", (unsigned long) duration);
 566
 567         /* Print msecs */
 568         ret = trace_seq_printf(s, "%s", msecs_str);
 569         if (!ret)
 570                 return TRACE_TYPE_PARTIAL_LINE;
 571
 572         len = strlen(msecs_str);
 573
 574         /* Print nsecs (we don't want to exceed 7 numbers) */
 575         if (len < 7) {
 576                 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
 577                 ret = trace_seq_printf(s, ".%s", nsecs_str);
 578                 if (!ret)
 579                         return TRACE_TYPE_PARTIAL_LINE;
 580                 len += strlen(nsecs_str);
 581         }
 582
 583         ret = trace_seq_printf(s, " us ");
 584         if (!ret)
 585                 return TRACE_TYPE_PARTIAL_LINE;
 586
 587         /* Print remaining spaces to fit the row's width */
 588         for (i = len; i < 7; i++) {
 589                 ret = trace_seq_printf(s, " ");
 590                 if (!ret)
 591                         return TRACE_TYPE_PARTIAL_LINE;
 592         }
 593         return TRACE_TYPE_HANDLED;
 594 }
 595
 596 static enum print_line_t
 597 print_graph_duration(unsigned long long duration, struct trace_seq *s)
 598 {
 599         int ret;
 600
 601         ret = trace_print_graph_duration(duration, s);
 602         if (ret != TRACE_TYPE_HANDLED)
 603                 return ret;
 604
 605         ret = trace_seq_printf(s, "|  ");
 606         if (!ret)
 607                 return TRACE_TYPE_PARTIAL_LINE;
 608
 609         return TRACE_TYPE_HANDLED;
 610 }
 611
 612 /* Case of a leaf function on its call entry */
 613 static enum print_line_t
 614 print_graph_entry_leaf(struct trace_iterator *iter,
 615                 struct ftrace_graph_ent_entry *entry,
 616                 struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s)
 617 {
 618         struct fgraph_data *data = iter->private;
 619         struct ftrace_graph_ret *graph_ret;
 620         struct ftrace_graph_ent *call;
 621         unsigned long long duration;
 622         int ret;
 623         int i;
 624
 625         graph_ret = &ret_entry->ret;
 626         call = &entry->graph_ent;
 627         duration = graph_ret->rettime - graph_ret->calltime;
 628
 629         if (data) {
 630                 int cpu = iter->cpu;
 631                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
 632
 633                 /*
 634                  * Comments display at + 1 to depth. Since
 635                  * this is a leaf function, keep the comments
 636                  * equal to this depth.
 637                  */
 638                 *depth = call->depth - 1;
 639         }
 640
 641         /* Overhead */
 642         ret = print_graph_overhead(duration, s);
 643         if (!ret)
 644                 return TRACE_TYPE_PARTIAL_LINE;
 645
 646         /* Duration */
 647         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 648                 ret = print_graph_duration(duration, s);
 649                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 650                         return TRACE_TYPE_PARTIAL_LINE;
 651         }
 652
 653         /* Function */
 654         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 655                 ret = trace_seq_printf(s, " ");
 656                 if (!ret)
 657                         return TRACE_TYPE_PARTIAL_LINE;
 658         }
 659
 660         ret = trace_seq_printf(s, "%pf();\n", (void *)call->func);
 661         if (!ret)
 662                 return TRACE_TYPE_PARTIAL_LINE;
 663
 664         return TRACE_TYPE_HANDLED;
 665 }
 666
 667 static enum print_line_t
 668 print_graph_entry_nested(struct trace_iterator *iter,
 669                          struct ftrace_graph_ent_entry *entry,
 670                          struct trace_seq *s, int cpu)
 671 {
 672         struct ftrace_graph_ent *call = &entry->graph_ent;
 673         struct fgraph_data *data = iter->private;
 674         int ret;
 675         int i;
 676
 677         if (data) {
 678                 int cpu = iter->cpu;
 679                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
 680
 681                 *depth = call->depth;
 682         }
 683
 684         /* No overhead */
 685         ret = print_graph_overhead(-1, s);
 686         if (!ret)
 687                 return TRACE_TYPE_PARTIAL_LINE;
 688
 689         /* No time */
 690         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 691                 ret = trace_seq_printf(s, "            |  ");
 692                 if (!ret)
 693                         return TRACE_TYPE_PARTIAL_LINE;
 694         }
 695
 696         /* Function */
 697         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 698                 ret = trace_seq_printf(s, " ");
 699                 if (!ret)
 700                         return TRACE_TYPE_PARTIAL_LINE;
 701         }
 702
 703         ret = trace_seq_printf(s, "%pf() {\n", (void *)call->func);
 704         if (!ret)
 705                 return TRACE_TYPE_PARTIAL_LINE;
 706
 707         /*
 708          * we already consumed the current entry to check the next one
 709          * and see if this is a leaf.
 710          */
 711         return TRACE_TYPE_NO_CONSUME;
 712 }
 713
 714 static enum print_line_t
 715 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 716                      int type, unsigned long addr)
 717 {
 718         struct fgraph_data *data = iter->private;
 719         struct trace_entry *ent = iter->ent;
 720         int cpu = iter->cpu;
 721         int ret;
 722
 723         /* Pid */
 724         if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
 725                 return TRACE_TYPE_PARTIAL_LINE;
 726
 727         if (type) {
 728                 /* Interrupt */
 729                 ret = print_graph_irq(iter, addr, type, cpu, ent->pid);
 730                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 731                         return TRACE_TYPE_PARTIAL_LINE;
 732         }
 733
 734         /* Absolute time */
 735         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 736                 ret = print_graph_abs_time(iter->ts, s);
 737                 if (!ret)
 738                         return TRACE_TYPE_PARTIAL_LINE;
 739         }
 740
 741         /* Cpu */
 742         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 743                 ret = print_graph_cpu(s, cpu);
 744                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 745                         return TRACE_TYPE_PARTIAL_LINE;
 746         }
 747
 748         /* Proc */
 749         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 750                 ret = print_graph_proc(s, ent->pid);
 751                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 752                         return TRACE_TYPE_PARTIAL_LINE;
 753
 754                 ret = trace_seq_printf(s, " | ");
 755                 if (!ret)
 756                         return TRACE_TYPE_PARTIAL_LINE;
 757         }
 758
 759         return 0;
 760 }
 761
 762 static enum print_line_t
 763 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 764                         struct trace_iterator *iter)
 765 {
 766         int cpu = iter->cpu;
 767         struct ftrace_graph_ent *call = &field->graph_ent;
 768         struct ftrace_graph_ret_entry *leaf_ret;
 769
 770         if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func))
 771                 return TRACE_TYPE_PARTIAL_LINE;
 772
 773         leaf_ret = get_return_for_leaf(iter, field);
 774         if (leaf_ret)
 775                 return print_graph_entry_leaf(iter, field, leaf_ret, s);
 776         else
 777                 return print_graph_entry_nested(iter, field, s, cpu);
 778
 779 }
 780
 781 static enum print_line_t
 782 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 783                    struct trace_entry *ent, struct trace_iterator *iter)
 784 {
 785         unsigned long long duration = trace->rettime - trace->calltime;
 786         struct fgraph_data *data = iter->private;
 787         pid_t pid = ent->pid;
 788         int cpu = iter->cpu;
 789         int ret;
 790         int i;
 791
 792         if (data) {
 793                 int cpu = iter->cpu;
 794                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
 795
 796                 /*
 797                  * Comments display at + 1 to depth. This is the
 798                  * return from a function, we now want the comments
 799                  * to display at the same level of the bracket.
 800                  */
 801                 *depth = trace->depth - 1;
 802         }
 803
 804         if (print_graph_prologue(iter, s, 0, 0))
 805                 return TRACE_TYPE_PARTIAL_LINE;
 806
 807         /* Overhead */
 808         ret = print_graph_overhead(duration, s);
 809         if (!ret)
 810                 return TRACE_TYPE_PARTIAL_LINE;
 811
 812         /* Duration */
 813         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 814                 ret = print_graph_duration(duration, s);
 815                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 816                         return TRACE_TYPE_PARTIAL_LINE;
 817         }
 818
 819         /* Closing brace */
 820         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
 821                 ret = trace_seq_printf(s, " ");
 822                 if (!ret)
 823                         return TRACE_TYPE_PARTIAL_LINE;
 824         }
 825
 826         ret = trace_seq_printf(s, "}\n");
 827         if (!ret)
 828                 return TRACE_TYPE_PARTIAL_LINE;
 829
 830         /* Overrun */
 831         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
 832                 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
 833                                         trace->overrun);
 834                 if (!ret)
 835                         return TRACE_TYPE_PARTIAL_LINE;
 836         }
 837
 838         ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid);
 839         if (ret == TRACE_TYPE_PARTIAL_LINE)
 840                 return TRACE_TYPE_PARTIAL_LINE;
 841
 842         return TRACE_TYPE_HANDLED;
 843 }
 844
 845 static enum print_line_t
 846 print_graph_comment(struct trace_seq *s,  struct trace_entry *ent,
 847                     struct trace_iterator *iter)
 848 {
 849         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
 850         struct fgraph_data *data = iter->private;
 851         struct trace_event *event;
 852         int depth = 0;
 853         int ret;
 854         int i;
 855
 856         if (data)
 857                 depth = per_cpu_ptr(data, iter->cpu)->depth;
 858
 859         if (print_graph_prologue(iter, s, 0, 0))
 860                 return TRACE_TYPE_PARTIAL_LINE;
 861
 862         /* No overhead */
 863         ret = print_graph_overhead(-1, s);
 864         if (!ret)
 865                 return TRACE_TYPE_PARTIAL_LINE;
 866
 867         /* No time */
 868         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 869                 ret = trace_seq_printf(s, "            |  ");
 870                 if (!ret)
 871                         return TRACE_TYPE_PARTIAL_LINE;
 872         }
 873
 874         /* Indentation */
 875         if (depth > 0)
 876                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
 877                         ret = trace_seq_printf(s, " ");
 878                         if (!ret)
 879                                 return TRACE_TYPE_PARTIAL_LINE;
 880                 }
 881
 882         /* The comment */
 883         ret = trace_seq_printf(s, "/* ");
 884         if (!ret)
 885                 return TRACE_TYPE_PARTIAL_LINE;
 886
 887         switch (iter->ent->type) {
 888         case TRACE_BPRINT:
 889                 ret = trace_print_bprintk_msg_only(iter);
 890                 if (ret != TRACE_TYPE_HANDLED)
 891                         return ret;
 892                 break;
 893         case TRACE_PRINT:
 894                 ret = trace_print_printk_msg_only(iter);
 895                 if (ret != TRACE_TYPE_HANDLED)
 896                         return ret;
 897                 break;
 898         default:
 899                 event = ftrace_find_event(ent->type);
 900                 if (!event)
 901                         return TRACE_TYPE_UNHANDLED;
 902
 903                 ret = event->trace(iter, sym_flags);
 904                 if (ret != TRACE_TYPE_HANDLED)
 905                         return ret;
 906         }
 907
 908         /* Strip ending newline */
 909         if (s->buffer[s->len - 1] == '\n') {
 910                 s->buffer[s->len - 1] = '\0';
 911                 s->len--;
 912         }
 913
 914         ret = trace_seq_printf(s, " */\n");
 915         if (!ret)
 916                 return TRACE_TYPE_PARTIAL_LINE;
 917
 918         return TRACE_TYPE_HANDLED;
 919 }
 920
 921
 922 enum print_line_t
 923 print_graph_function(struct trace_iterator *iter)
 924 {
 925         struct trace_entry *entry = iter->ent;
 926         struct trace_seq *s = &iter->seq;
 927
 928         switch (entry->type) {
 929         case TRACE_GRAPH_ENT: {
 930                 /*
 931                  * print_graph_entry() may consume the current event,
 932                  * thus @field may become invalid, so we need to save it.
 933                  * sizeof(struct ftrace_graph_ent_entry) is very small,
 934                  * it can be safely saved at the stack.
 935                  */
 936                 struct ftrace_graph_ent_entry *field, saved;
 937                 trace_assign_type(field, entry);
 938                 saved = *field;
 939                 return print_graph_entry(&saved, s, iter);
 940         }
 941         case TRACE_GRAPH_RET: {
 942                 struct ftrace_graph_ret_entry *field;
 943                 trace_assign_type(field, entry);
 944                 return print_graph_return(&field->ret, s, entry, iter);
 945         }
 946         default:
 947                 return print_graph_comment(s, entry, iter);
 948         }
 949
 950         return TRACE_TYPE_HANDLED;
 951 }
 952
 953 static void print_graph_headers(struct seq_file *s)
 954 {
 955         /* 1st line */
 956         seq_printf(s, "# ");
 957         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 958                 seq_printf(s, "     TIME       ");
 959         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 960                 seq_printf(s, "CPU");
 961         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 962                 seq_printf(s, "  TASK/PID      ");
 963         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 964                 seq_printf(s, "  DURATION   ");
 965         seq_printf(s, "               FUNCTION CALLS\n");
 966
 967         /* 2nd line */
 968         seq_printf(s, "# ");
 969         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 970                 seq_printf(s, "      |         ");
 971         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 972                 seq_printf(s, "|  ");
 973         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 974                 seq_printf(s, "  |    |        ");
 975         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 976                 seq_printf(s, "   |   |      ");
 977         seq_printf(s, "               |   |   |   |\n");
 978 }
 979
 980 static void graph_trace_open(struct trace_iterator *iter)
 981 {
 982         /* pid and depth on the last trace processed */
 983         struct fgraph_data *data = alloc_percpu(struct fgraph_data);
 984         int cpu;
 985
 986         if (!data)
 987                 pr_warning("function graph tracer: not enough memory\n");
 988         else
 989                 for_each_possible_cpu(cpu) {
 990                         pid_t *pid = &(per_cpu_ptr(data, cpu)->last_pid);
 991                         int *depth = &(per_cpu_ptr(data, cpu)->depth);
 992                         *pid = -1;
 993                         *depth = 0;
 994                 }
 995
 996         iter->private = data;
 997 }
 998
 999 static void graph_trace_close(struct trace_iterator *iter)
1000 {
1001         free_percpu(iter->private);
1002 }
1003
1004 static struct tracer graph_trace __read_mostly = {
1005         .name           = "function_graph",
1006         .open           = graph_trace_open,
1007         .close          = graph_trace_close,
1008         .wait_pipe      = poll_wait_pipe,
1009         .init           = graph_trace_init,
1010         .reset          = graph_trace_reset,
1011         .print_line     = print_graph_function,
1012         .print_header   = print_graph_headers,
1013         .flags          = &tracer_flags,
1014 #ifdef CONFIG_FTRACE_SELFTEST
1015         .selftest       = trace_selftest_startup_function_graph,
1016 #endif
1017 };
1018
1019 static __init int init_graph_trace(void)
1020 {
1021         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1022
1023         return register_tracer(&graph_trace);
1024 }
1025
1026 device_initcall(init_graph_trace);