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 ring_buffer *buffer = tr->buffer;
 177         struct ftrace_graph_ent_entry *entry;
 178
 179         if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
 180                 return 0;
 181
 182         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
 183                                           sizeof(*entry), flags, pc);
 184         if (!event)
 185                 return 0;
 186         entry   = ring_buffer_event_data(event);
 187         entry->graph_ent                        = *trace;
 188         if (!filter_current_check_discard(buffer, call, entry, event))
 189                 ring_buffer_unlock_commit(buffer, event);
 190
 191         return 1;
 192 }
 193
 194 int trace_graph_entry(struct ftrace_graph_ent *trace)
 195 {
 196         struct trace_array *tr = graph_array;
 197         struct trace_array_cpu *data;
 198         unsigned long flags;
 199         long disabled;
 200         int ret;
 201         int cpu;
 202         int pc;
 203
 204         if (unlikely(!tr))
 205                 return 0;
 206
 207         if (!ftrace_trace_task(current))
 208                 return 0;
 209
 210         if (!ftrace_graph_addr(trace->func))
 211                 return 0;
 212
 213         local_irq_save(flags);
 214         cpu = raw_smp_processor_id();
 215         data = tr->data[cpu];
 216         disabled = atomic_inc_return(&data->disabled);
 217         if (likely(disabled == 1)) {
 218                 pc = preempt_count();
 219                 ret = __trace_graph_entry(tr, trace, flags, pc);
 220         } else {
 221                 ret = 0;
 222         }
 223         /* Only do the atomic if it is not already set */
 224         if (!test_tsk_trace_graph(current))
 225                 set_tsk_trace_graph(current);
 226
 227         atomic_dec(&data->disabled);
 228         local_irq_restore(flags);
 229
 230         return ret;
 231 }
 232
 233 static void __trace_graph_return(struct trace_array *tr,
 234                                 struct ftrace_graph_ret *trace,
 235                                 unsigned long flags,
 236                                 int pc)
 237 {
 238         struct ftrace_event_call *call = &event_funcgraph_exit;
 239         struct ring_buffer_event *event;
 240         struct ring_buffer *buffer = tr->buffer;
 241         struct ftrace_graph_ret_entry *entry;
 242
 243         if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
 244                 return;
 245
 246         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
 247                                           sizeof(*entry), flags, pc);
 248         if (!event)
 249                 return;
 250         entry   = ring_buffer_event_data(event);
 251         entry->ret                              = *trace;
 252         if (!filter_current_check_discard(buffer, call, entry, event))
 253                 ring_buffer_unlock_commit(buffer, event);
 254 }
 255
 256 void trace_graph_return(struct ftrace_graph_ret *trace)
 257 {
 258         struct trace_array *tr = graph_array;
 259         struct trace_array_cpu *data;
 260         unsigned long flags;
 261         long disabled;
 262         int cpu;
 263         int pc;
 264
 265         local_irq_save(flags);
 266         cpu = raw_smp_processor_id();
 267         data = tr->data[cpu];
 268         disabled = atomic_inc_return(&data->disabled);
 269         if (likely(disabled == 1)) {
 270                 pc = preempt_count();
 271                 __trace_graph_return(tr, trace, flags, pc);
 272         }
 273         if (!trace->depth)
 274                 clear_tsk_trace_graph(current);
 275         atomic_dec(&data->disabled);
 276         local_irq_restore(flags);
 277 }
 278
 279 static int graph_trace_init(struct trace_array *tr)
 280 {
 281         int ret;
 282
 283         graph_array = tr;
 284         ret = register_ftrace_graph(&trace_graph_return,
 285                                     &trace_graph_entry);
 286         if (ret)
 287                 return ret;
 288         tracing_start_cmdline_record();
 289
 290         return 0;
 291 }
 292
 293 void set_graph_array(struct trace_array *tr)
 294 {
 295         graph_array = tr;
 296 }
 297
 298 static void graph_trace_reset(struct trace_array *tr)
 299 {
 300         tracing_stop_cmdline_record();
 301         unregister_ftrace_graph();
 302 }
 303
 304 static int max_bytes_for_cpu;
 305
 306 static enum print_line_t
 307 print_graph_cpu(struct trace_seq *s, int cpu)
 308 {
 309         int ret;
 310
 311         /*
 312          * Start with a space character - to make it stand out
 313          * to the right a bit when trace output is pasted into
 314          * email:
 315          */
 316         ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 317         if (!ret)
 318                 return TRACE_TYPE_PARTIAL_LINE;
 319
 320         return TRACE_TYPE_HANDLED;
 321 }
 322
 323 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 324
 325 static enum print_line_t
 326 print_graph_proc(struct trace_seq *s, pid_t pid)
 327 {
 328         char comm[TASK_COMM_LEN];
 329         /* sign + log10(MAX_INT) + '\0' */
 330         char pid_str[11];
 331         int spaces = 0;
 332         int ret;
 333         int len;
 334         int i;
 335
 336         trace_find_cmdline(pid, comm);
 337         comm[7] = '\0';
 338         sprintf(pid_str, "%d", pid);
 339
 340         /* 1 stands for the "-" character */
 341         len = strlen(comm) + strlen(pid_str) + 1;
 342
 343         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 344                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 345
 346         /* First spaces to align center */
 347         for (i = 0; i < spaces / 2; i++) {
 348                 ret = trace_seq_printf(s, " ");
 349                 if (!ret)
 350                         return TRACE_TYPE_PARTIAL_LINE;
 351         }
 352
 353         ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
 354         if (!ret)
 355                 return TRACE_TYPE_PARTIAL_LINE;
 356
 357         /* Last spaces to align center */
 358         for (i = 0; i < spaces - (spaces / 2); i++) {
 359                 ret = trace_seq_printf(s, " ");
 360                 if (!ret)
 361                         return TRACE_TYPE_PARTIAL_LINE;
 362         }
 363         return TRACE_TYPE_HANDLED;
 364 }
 365
 366
 367 /* If the pid changed since the last trace, output this event */
 368 static enum print_line_t
 369 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 370 {
 371         pid_t prev_pid;
 372         pid_t *last_pid;
 373         int ret;
 374
 375         if (!data)
 376                 return TRACE_TYPE_HANDLED;
 377
 378         last_pid = &(per_cpu_ptr(data, cpu)->last_pid);
 379
 380         if (*last_pid == pid)
 381                 return TRACE_TYPE_HANDLED;
 382
 383         prev_pid = *last_pid;
 384         *last_pid = pid;
 385
 386         if (prev_pid == -1)
 387                 return TRACE_TYPE_HANDLED;
 388 /*
 389  * Context-switch trace line:
 390
 391  ------------------------------------------
 392  | 1)  migration/0--1  =>  sshd-1755
 393  ------------------------------------------
 394
 395  */
 396         ret = trace_seq_printf(s,
 397                 " ------------------------------------------\n");
 398         if (!ret)
 399                 return TRACE_TYPE_PARTIAL_LINE;
 400
 401         ret = print_graph_cpu(s, cpu);
 402         if (ret == TRACE_TYPE_PARTIAL_LINE)
 403                 return TRACE_TYPE_PARTIAL_LINE;
 404
 405         ret = print_graph_proc(s, prev_pid);
 406         if (ret == TRACE_TYPE_PARTIAL_LINE)
 407                 return TRACE_TYPE_PARTIAL_LINE;
 408
 409         ret = trace_seq_printf(s, " => ");
 410         if (!ret)
 411                 return TRACE_TYPE_PARTIAL_LINE;
 412
 413         ret = print_graph_proc(s, pid);
 414         if (ret == TRACE_TYPE_PARTIAL_LINE)
 415                 return TRACE_TYPE_PARTIAL_LINE;
 416
 417         ret = trace_seq_printf(s,
 418                 "\n ------------------------------------------\n\n");
 419         if (!ret)
 420                 return TRACE_TYPE_PARTIAL_LINE;
 421
 422         return TRACE_TYPE_HANDLED;
 423 }
 424
 425 static struct ftrace_graph_ret_entry *
 426 get_return_for_leaf(struct trace_iterator *iter,
 427                 struct ftrace_graph_ent_entry *curr)
 428 {
 429         struct ring_buffer_iter *ring_iter;
 430         struct ring_buffer_event *event;
 431         struct ftrace_graph_ret_entry *next;
 432
 433         ring_iter = iter->buffer_iter[iter->cpu];
 434
 435         /* First peek to compare current entry and the next one */
 436         if (ring_iter)
 437                 event = ring_buffer_iter_peek(ring_iter, NULL);
 438         else {
 439         /* We need to consume the current entry to see the next one */
 440                 ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
 441                 event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
 442                                         NULL);
 443         }
 444
 445         if (!event)
 446                 return NULL;
 447
 448         next = ring_buffer_event_data(event);
 449
 450         if (next->ent.type != TRACE_GRAPH_RET)
 451                 return NULL;
 452
 453         if (curr->ent.pid != next->ent.pid ||
 454                         curr->graph_ent.func != next->ret.func)
 455                 return NULL;
 456
 457         /* this is a leaf, now advance the iterator */
 458         if (ring_iter)
 459                 ring_buffer_read(ring_iter, NULL);
 460
 461         return next;
 462 }
 463
 464 /* Signal a overhead of time execution to the output */
 465 static int
 466 print_graph_overhead(unsigned long long duration, struct trace_seq *s)
 467 {
 468         /* If duration disappear, we don't need anything */
 469         if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION))
 470                 return 1;
 471
 472         /* Non nested entry or return */
 473         if (duration == -1)
 474                 return trace_seq_printf(s, "  ");
 475
 476         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
 477                 /* Duration exceeded 100 msecs */
 478                 if (duration > 100000ULL)
 479                         return trace_seq_printf(s, "! ");
 480
 481                 /* Duration exceeded 10 msecs */
 482                 if (duration > 10000ULL)
 483                         return trace_seq_printf(s, "+ ");
 484         }
 485
 486         return trace_seq_printf(s, "  ");
 487 }
 488
 489 static int print_graph_abs_time(u64 t, struct trace_seq *s)
 490 {
 491         unsigned long usecs_rem;
 492
 493         usecs_rem = do_div(t, NSEC_PER_SEC);
 494         usecs_rem /= 1000;
 495
 496         return trace_seq_printf(s, "%5lu.%06lu |  ",
 497                         (unsigned long)t, usecs_rem);
 498 }
 499
 500 static enum print_line_t
 501 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 502                 enum trace_type type, int cpu, pid_t pid)
 503 {
 504         int ret;
 505         struct trace_seq *s = &iter->seq;
 506
 507         if (addr < (unsigned long)__irqentry_text_start ||
 508                 addr >= (unsigned long)__irqentry_text_end)
 509                 return TRACE_TYPE_UNHANDLED;
 510
 511         /* Absolute time */
 512         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 513                 ret = print_graph_abs_time(iter->ts, s);
 514                 if (!ret)
 515                         return TRACE_TYPE_PARTIAL_LINE;
 516         }
 517
 518         /* Cpu */
 519         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 520                 ret = print_graph_cpu(s, cpu);
 521                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 522                         return TRACE_TYPE_PARTIAL_LINE;
 523         }
 524         /* Proc */
 525         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 526                 ret = print_graph_proc(s, pid);
 527                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 528                         return TRACE_TYPE_PARTIAL_LINE;
 529                 ret = trace_seq_printf(s, " | ");
 530                 if (!ret)
 531                         return TRACE_TYPE_PARTIAL_LINE;
 532         }
 533
 534         /* No overhead */
 535         ret = print_graph_overhead(-1, s);
 536         if (!ret)
 537                 return TRACE_TYPE_PARTIAL_LINE;
 538
 539         if (type == TRACE_GRAPH_ENT)
 540                 ret = trace_seq_printf(s, "==========>");
 541         else
 542                 ret = trace_seq_printf(s, "<==========");
 543
 544         if (!ret)
 545                 return TRACE_TYPE_PARTIAL_LINE;
 546
 547         /* Don't close the duration column if haven't one */
 548         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 549                 trace_seq_printf(s, " |");
 550         ret = trace_seq_printf(s, "\n");
 551
 552         if (!ret)
 553                 return TRACE_TYPE_PARTIAL_LINE;
 554         return TRACE_TYPE_HANDLED;
 555 }
 556
 557 enum print_line_t
 558 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 559 {
 560         unsigned long nsecs_rem = do_div(duration, 1000);
 561         /* log10(ULONG_MAX) + '\0' */
 562         char msecs_str[21];
 563         char nsecs_str[5];
 564         int ret, len;
 565         int i;
 566
 567         sprintf(msecs_str, "%lu", (unsigned long) duration);
 568
 569         /* Print msecs */
 570         ret = trace_seq_printf(s, "%s", msecs_str);
 571         if (!ret)
 572                 return TRACE_TYPE_PARTIAL_LINE;
 573
 574         len = strlen(msecs_str);
 575
 576         /* Print nsecs (we don't want to exceed 7 numbers) */
 577         if (len < 7) {
 578                 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
 579                 ret = trace_seq_printf(s, ".%s", nsecs_str);
 580                 if (!ret)
 581                         return TRACE_TYPE_PARTIAL_LINE;
 582                 len += strlen(nsecs_str);
 583         }
 584
 585         ret = trace_seq_printf(s, " us ");
 586         if (!ret)
 587                 return TRACE_TYPE_PARTIAL_LINE;
 588
 589         /* Print remaining spaces to fit the row's width */
 590         for (i = len; i < 7; i++) {
 591                 ret = trace_seq_printf(s, " ");
 592                 if (!ret)
 593                         return TRACE_TYPE_PARTIAL_LINE;
 594         }
 595         return TRACE_TYPE_HANDLED;
 596 }
 597
 598 static enum print_line_t
 599 print_graph_duration(unsigned long long duration, struct trace_seq *s)
 600 {
 601         int ret;
 602
 603         ret = trace_print_graph_duration(duration, s);
 604         if (ret != TRACE_TYPE_HANDLED)
 605                 return ret;
 606
 607         ret = trace_seq_printf(s, "|  ");
 608         if (!ret)
 609                 return TRACE_TYPE_PARTIAL_LINE;
 610
 611         return TRACE_TYPE_HANDLED;
 612 }
 613
 614 /* Case of a leaf function on its call entry */
 615 static enum print_line_t
 616 print_graph_entry_leaf(struct trace_iterator *iter,
 617                 struct ftrace_graph_ent_entry *entry,
 618                 struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s)
 619 {
 620         struct fgraph_data *data = iter->private;
 621         struct ftrace_graph_ret *graph_ret;
 622         struct ftrace_graph_ent *call;
 623         unsigned long long duration;
 624         int ret;
 625         int i;
 626
 627         graph_ret = &ret_entry->ret;
 628         call = &entry->graph_ent;
 629         duration = graph_ret->rettime - graph_ret->calltime;
 630
 631         if (data) {
 632                 int cpu = iter->cpu;
 633                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
 634
 635                 /*
 636                  * Comments display at + 1 to depth. Since
 637                  * this is a leaf function, keep the comments
 638                  * equal to this depth.
 639                  */
 640                 *depth = call->depth - 1;
 641         }
 642
 643         /* Overhead */
 644         ret = print_graph_overhead(duration, s);
 645         if (!ret)
 646                 return TRACE_TYPE_PARTIAL_LINE;
 647
 648         /* Duration */
 649         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 650                 ret = print_graph_duration(duration, s);
 651                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 652                         return TRACE_TYPE_PARTIAL_LINE;
 653         }
 654
 655         /* Function */
 656         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 657                 ret = trace_seq_printf(s, " ");
 658                 if (!ret)
 659                         return TRACE_TYPE_PARTIAL_LINE;
 660         }
 661
 662         ret = trace_seq_printf(s, "%pf();\n", (void *)call->func);
 663         if (!ret)
 664                 return TRACE_TYPE_PARTIAL_LINE;
 665
 666         return TRACE_TYPE_HANDLED;
 667 }
 668
 669 static enum print_line_t
 670 print_graph_entry_nested(struct trace_iterator *iter,
 671                          struct ftrace_graph_ent_entry *entry,
 672                          struct trace_seq *s, int cpu)
 673 {
 674         struct ftrace_graph_ent *call = &entry->graph_ent;
 675         struct fgraph_data *data = iter->private;
 676         int ret;
 677         int i;
 678
 679         if (data) {
 680                 int cpu = iter->cpu;
 681                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
 682
 683                 *depth = call->depth;
 684         }
 685
 686         /* No overhead */
 687         ret = print_graph_overhead(-1, s);
 688         if (!ret)
 689                 return TRACE_TYPE_PARTIAL_LINE;
 690
 691         /* No time */
 692         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 693                 ret = trace_seq_printf(s, "            |  ");
 694                 if (!ret)
 695                         return TRACE_TYPE_PARTIAL_LINE;
 696         }
 697
 698         /* Function */
 699         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 700                 ret = trace_seq_printf(s, " ");
 701                 if (!ret)
 702                         return TRACE_TYPE_PARTIAL_LINE;
 703         }
 704
 705         ret = trace_seq_printf(s, "%pf() {\n", (void *)call->func);
 706         if (!ret)
 707                 return TRACE_TYPE_PARTIAL_LINE;
 708
 709         /*
 710          * we already consumed the current entry to check the next one
 711          * and see if this is a leaf.
 712          */
 713         return TRACE_TYPE_NO_CONSUME;
 714 }
 715
 716 static enum print_line_t
 717 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 718                      int type, unsigned long addr)
 719 {
 720         struct fgraph_data *data = iter->private;
 721         struct trace_entry *ent = iter->ent;
 722         int cpu = iter->cpu;
 723         int ret;
 724
 725         /* Pid */
 726         if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
 727                 return TRACE_TYPE_PARTIAL_LINE;
 728
 729         if (type) {
 730                 /* Interrupt */
 731                 ret = print_graph_irq(iter, addr, type, cpu, ent->pid);
 732                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 733                         return TRACE_TYPE_PARTIAL_LINE;
 734         }
 735
 736         /* Absolute time */
 737         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 738                 ret = print_graph_abs_time(iter->ts, s);
 739                 if (!ret)
 740                         return TRACE_TYPE_PARTIAL_LINE;
 741         }
 742
 743         /* Cpu */
 744         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 745                 ret = print_graph_cpu(s, cpu);
 746                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 747                         return TRACE_TYPE_PARTIAL_LINE;
 748         }
 749
 750         /* Proc */
 751         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 752                 ret = print_graph_proc(s, ent->pid);
 753                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 754                         return TRACE_TYPE_PARTIAL_LINE;
 755
 756                 ret = trace_seq_printf(s, " | ");
 757                 if (!ret)
 758                         return TRACE_TYPE_PARTIAL_LINE;
 759         }
 760
 761         return 0;
 762 }
 763
 764 static enum print_line_t
 765 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 766                         struct trace_iterator *iter)
 767 {
 768         int cpu = iter->cpu;
 769         struct ftrace_graph_ent *call = &field->graph_ent;
 770         struct ftrace_graph_ret_entry *leaf_ret;
 771
 772         if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func))
 773                 return TRACE_TYPE_PARTIAL_LINE;
 774
 775         leaf_ret = get_return_for_leaf(iter, field);
 776         if (leaf_ret)
 777                 return print_graph_entry_leaf(iter, field, leaf_ret, s);
 778         else
 779                 return print_graph_entry_nested(iter, field, s, cpu);
 780
 781 }
 782
 783 static enum print_line_t
 784 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 785                    struct trace_entry *ent, struct trace_iterator *iter)
 786 {
 787         unsigned long long duration = trace->rettime - trace->calltime;
 788         struct fgraph_data *data = iter->private;
 789         pid_t pid = ent->pid;
 790         int cpu = iter->cpu;
 791         int ret;
 792         int i;
 793
 794         if (data) {
 795                 int cpu = iter->cpu;
 796                 int *depth = &(per_cpu_ptr(data, cpu)->depth);
 797
 798                 /*
 799                  * Comments display at + 1 to depth. This is the
 800                  * return from a function, we now want the comments
 801                  * to display at the same level of the bracket.
 802                  */
 803                 *depth = trace->depth - 1;
 804         }
 805
 806         if (print_graph_prologue(iter, s, 0, 0))
 807                 return TRACE_TYPE_PARTIAL_LINE;
 808
 809         /* Overhead */
 810         ret = print_graph_overhead(duration, s);
 811         if (!ret)
 812                 return TRACE_TYPE_PARTIAL_LINE;
 813
 814         /* Duration */
 815         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 816                 ret = print_graph_duration(duration, s);
 817                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 818                         return TRACE_TYPE_PARTIAL_LINE;
 819         }
 820
 821         /* Closing brace */
 822         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
 823                 ret = trace_seq_printf(s, " ");
 824                 if (!ret)
 825                         return TRACE_TYPE_PARTIAL_LINE;
 826         }
 827
 828         ret = trace_seq_printf(s, "}\n");
 829         if (!ret)
 830                 return TRACE_TYPE_PARTIAL_LINE;
 831
 832         /* Overrun */
 833         if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
 834                 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
 835                                         trace->overrun);
 836                 if (!ret)
 837                         return TRACE_TYPE_PARTIAL_LINE;
 838         }
 839
 840         ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid);
 841         if (ret == TRACE_TYPE_PARTIAL_LINE)
 842                 return TRACE_TYPE_PARTIAL_LINE;
 843
 844         return TRACE_TYPE_HANDLED;
 845 }
 846
 847 static enum print_line_t
 848 print_graph_comment(struct trace_seq *s,  struct trace_entry *ent,
 849                     struct trace_iterator *iter)
 850 {
 851         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
 852         struct fgraph_data *data = iter->private;
 853         struct trace_event *event;
 854         int depth = 0;
 855         int ret;
 856         int i;
 857
 858         if (data)
 859                 depth = per_cpu_ptr(data, iter->cpu)->depth;
 860
 861         if (print_graph_prologue(iter, s, 0, 0))
 862                 return TRACE_TYPE_PARTIAL_LINE;
 863
 864         /* No overhead */
 865         ret = print_graph_overhead(-1, s);
 866         if (!ret)
 867                 return TRACE_TYPE_PARTIAL_LINE;
 868
 869         /* No time */
 870         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 871                 ret = trace_seq_printf(s, "            |  ");
 872                 if (!ret)
 873                         return TRACE_TYPE_PARTIAL_LINE;
 874         }
 875
 876         /* Indentation */
 877         if (depth > 0)
 878                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
 879                         ret = trace_seq_printf(s, " ");
 880                         if (!ret)
 881                                 return TRACE_TYPE_PARTIAL_LINE;
 882                 }
 883
 884         /* The comment */
 885         ret = trace_seq_printf(s, "/* ");
 886         if (!ret)
 887                 return TRACE_TYPE_PARTIAL_LINE;
 888
 889         switch (iter->ent->type) {
 890         case TRACE_BPRINT:
 891                 ret = trace_print_bprintk_msg_only(iter);
 892                 if (ret != TRACE_TYPE_HANDLED)
 893                         return ret;
 894                 break;
 895         case TRACE_PRINT:
 896                 ret = trace_print_printk_msg_only(iter);
 897                 if (ret != TRACE_TYPE_HANDLED)
 898                         return ret;
 899                 break;
 900         default:
 901                 event = ftrace_find_event(ent->type);
 902                 if (!event)
 903                         return TRACE_TYPE_UNHANDLED;
 904
 905                 ret = event->trace(iter, sym_flags);
 906                 if (ret != TRACE_TYPE_HANDLED)
 907                         return ret;
 908         }
 909
 910         /* Strip ending newline */
 911         if (s->buffer[s->len - 1] == '\n') {
 912                 s->buffer[s->len - 1] = '\0';
 913                 s->len--;
 914         }
 915
 916         ret = trace_seq_printf(s, " */\n");
 917         if (!ret)
 918                 return TRACE_TYPE_PARTIAL_LINE;
 919
 920         return TRACE_TYPE_HANDLED;
 921 }
 922
 923
 924 enum print_line_t
 925 print_graph_function(struct trace_iterator *iter)
 926 {
 927         struct trace_entry *entry = iter->ent;
 928         struct trace_seq *s = &iter->seq;
 929
 930         switch (entry->type) {
 931         case TRACE_GRAPH_ENT: {
 932                 /*
 933                  * print_graph_entry() may consume the current event,
 934                  * thus @field may become invalid, so we need to save it.
 935                  * sizeof(struct ftrace_graph_ent_entry) is very small,
 936                  * it can be safely saved at the stack.
 937                  */
 938                 struct ftrace_graph_ent_entry *field, saved;
 939                 trace_assign_type(field, entry);
 940                 saved = *field;
 941                 return print_graph_entry(&saved, s, iter);
 942         }
 943         case TRACE_GRAPH_RET: {
 944                 struct ftrace_graph_ret_entry *field;
 945                 trace_assign_type(field, entry);
 946                 return print_graph_return(&field->ret, s, entry, iter);
 947         }
 948         default:
 949                 return print_graph_comment(s, entry, iter);
 950         }
 951
 952         return TRACE_TYPE_HANDLED;
 953 }
 954
 955 static void print_graph_headers(struct seq_file *s)
 956 {
 957         /* 1st line */
 958         seq_printf(s, "# ");
 959         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 960                 seq_printf(s, "     TIME       ");
 961         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 962                 seq_printf(s, "CPU");
 963         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 964                 seq_printf(s, "  TASK/PID      ");
 965         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 966                 seq_printf(s, "  DURATION   ");
 967         seq_printf(s, "               FUNCTION CALLS\n");
 968
 969         /* 2nd line */
 970         seq_printf(s, "# ");
 971         if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 972                 seq_printf(s, "      |         ");
 973         if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 974                 seq_printf(s, "|  ");
 975         if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 976                 seq_printf(s, "  |    |        ");
 977         if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 978                 seq_printf(s, "   |   |      ");
 979         seq_printf(s, "               |   |   |   |\n");
 980 }
 981
 982 static void graph_trace_open(struct trace_iterator *iter)
 983 {
 984         /* pid and depth on the last trace processed */
 985         struct fgraph_data *data = alloc_percpu(struct fgraph_data);
 986         int cpu;
 987
 988         if (!data)
 989                 pr_warning("function graph tracer: not enough memory\n");
 990         else
 991                 for_each_possible_cpu(cpu) {
 992                         pid_t *pid = &(per_cpu_ptr(data, cpu)->last_pid);
 993                         int *depth = &(per_cpu_ptr(data, cpu)->depth);
 994                         *pid = -1;
 995                         *depth = 0;
 996                 }
 997
 998         iter->private = data;
 999 }
1000
1001 static void graph_trace_close(struct trace_iterator *iter)
1002 {
1003         free_percpu(iter->private);
1004 }
1005
1006 static struct tracer graph_trace __read_mostly = {
1007         .name           = "function_graph",
1008         .open           = graph_trace_open,
1009         .close          = graph_trace_close,
1010         .wait_pipe      = poll_wait_pipe,
1011         .init           = graph_trace_init,
1012         .reset          = graph_trace_reset,
1013         .print_line     = print_graph_function,
1014         .print_header   = print_graph_headers,
1015         .flags          = &tracer_flags,
1016 #ifdef CONFIG_FTRACE_SELFTEST
1017         .selftest       = trace_selftest_startup_function_graph,
1018 #endif
1019 };
1020
1021 static __init int init_graph_trace(void)
1022 {
1023         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1024
1025         return register_tracer(&graph_trace);
1026 }
1027
1028 device_initcall(init_graph_trace);