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/slab.h>
  13 #include <linux/fs.h>
  14
  15 #include "trace.h"
  16 #include "trace_output.h"
  17
  18 struct fgraph_cpu_data {
  19         pid_t           last_pid;
  20         int             depth;
  21         int             ignore;
  22         unsigned long   enter_funcs[FTRACE_RETFUNC_DEPTH];
  23 };
  24
  25 struct fgraph_data {
  26         struct fgraph_cpu_data          *cpu_data;
  27
  28         /* Place to preserve last processed entry. */
  29         struct ftrace_graph_ent_entry   ent;
  30         struct ftrace_graph_ret_entry   ret;
  31         int                             failed;
  32         int                             cpu;
  33 };
  34
  35 #define TRACE_GRAPH_INDENT      2
  36
  37 /* Flag options */
  38 #define TRACE_GRAPH_PRINT_OVERRUN       0x1
  39 #define TRACE_GRAPH_PRINT_CPU           0x2
  40 #define TRACE_GRAPH_PRINT_OVERHEAD      0x4
  41 #define TRACE_GRAPH_PRINT_PROC          0x8
  42 #define TRACE_GRAPH_PRINT_DURATION      0x10
  43 #define TRACE_GRAPH_PRINT_ABS_TIME      0x20
  44
  45 static struct tracer_opt trace_opts[] = {
  46         /* Display overruns? (for self-debug purpose) */
  47         { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
  48         /* Display CPU ? */
  49         { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
  50         /* Display Overhead ? */
  51         { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
  52         /* Display proc name/pid */
  53         { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
  54         /* Display duration of execution */
  55         { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
  56         /* Display absolute time of an entry */
  57         { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
  58         { } /* Empty entry */
  59 };
  60
  61 static struct tracer_flags tracer_flags = {
  62         /* Don't display overruns and proc by default */
  63         .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
  64                TRACE_GRAPH_PRINT_DURATION,
  65         .opts = trace_opts
  66 };
  67
  68 static struct trace_array *graph_array;
  69
  70
  71 /* Add a function return address to the trace stack on thread info.*/
  72 int
  73 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
  74                          unsigned long frame_pointer)
  75 {
  76         unsigned long long calltime;
  77         int index;
  78
  79         if (!current->ret_stack)
  80                 return -EBUSY;
  81
  82         /*
  83          * We must make sure the ret_stack is tested before we read
  84          * anything else.
  85          */
  86         smp_rmb();
  87
  88         /* The return trace stack is full */
  89         if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
  90                 atomic_inc(&current->trace_overrun);
  91                 return -EBUSY;
  92         }
  93
  94         calltime = trace_clock_local();
  95
  96         index = ++current->curr_ret_stack;
  97         barrier();
  98         current->ret_stack[index].ret = ret;
  99         current->ret_stack[index].func = func;
 100         current->ret_stack[index].calltime = calltime;
 101         current->ret_stack[index].subtime = 0;
 102         current->ret_stack[index].fp = frame_pointer;
 103         *depth = index;
 104
 105         return 0;
 106 }
 107
 108 /* Retrieve a function return address to the trace stack on thread info.*/
 109 static void
 110 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
 111                         unsigned long frame_pointer)
 112 {
 113         int index;
 114
 115         index = current->curr_ret_stack;
 116
 117         if (unlikely(index < 0)) {
 118                 ftrace_graph_stop();
 119                 WARN_ON(1);
 120                 /* Might as well panic, otherwise we have no where to go */
 121                 *ret = (unsigned long)panic;
 122                 return;
 123         }
 124
 125 #ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
 126         /*
 127          * The arch may choose to record the frame pointer used
 128          * and check it here to make sure that it is what we expect it
 129          * to be. If gcc does not set the place holder of the return
 130          * address in the frame pointer, and does a copy instead, then
 131          * the function graph trace will fail. This test detects this
 132          * case.
 133          *
 134          * Currently, x86_32 with optimize for size (-Os) makes the latest
 135          * gcc do the above.
 136          */
 137         if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
 138                 ftrace_graph_stop();
 139                 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
 140                      "  from func %ps return to %lx\n",
 141                      current->ret_stack[index].fp,
 142                      frame_pointer,
 143                      (void *)current->ret_stack[index].func,
 144                      current->ret_stack[index].ret);
 145                 *ret = (unsigned long)panic;
 146                 return;
 147         }
 148 #endif
 149
 150         *ret = current->ret_stack[index].ret;
 151         trace->func = current->ret_stack[index].func;
 152         trace->calltime = current->ret_stack[index].calltime;
 153         trace->overrun = atomic_read(&current->trace_overrun);
 154         trace->depth = index;
 155 }
 156
 157 /*
 158  * Send the trace to the ring-buffer.
 159  * @return the original return address.
 160  */
 161 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 162 {
 163         struct ftrace_graph_ret trace;
 164         unsigned long ret;
 165
 166         ftrace_pop_return_trace(&trace, &ret, frame_pointer);
 167         trace.rettime = trace_clock_local();
 168         ftrace_graph_return(&trace);
 169         barrier();
 170         current->curr_ret_stack--;
 171
 172         if (unlikely(!ret)) {
 173                 ftrace_graph_stop();
 174                 WARN_ON(1);
 175                 /* Might as well panic. What else to do? */
 176                 ret = (unsigned long)panic;
 177         }
 178
 179         return ret;
 180 }
 181
 182 int __trace_graph_entry(struct trace_array *tr,
 183                                 struct ftrace_graph_ent *trace,
 184                                 unsigned long flags,
 185                                 int pc)
 186 {
 187         struct ftrace_event_call *call = &event_funcgraph_entry;
 188         struct ring_buffer_event *event;
 189         struct ring_buffer *buffer = tr->buffer;
 190         struct ftrace_graph_ent_entry *entry;
 191
 192         if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
 193                 return 0;
 194
 195         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
 196                                           sizeof(*entry), flags, pc);
 197         if (!event)
 198                 return 0;
 199         entry   = ring_buffer_event_data(event);
 200         entry->graph_ent                        = *trace;
 201         if (!filter_current_check_discard(buffer, call, entry, event))
 202                 ring_buffer_unlock_commit(buffer, event);
 203
 204         return 1;
 205 }
 206
 207 int trace_graph_entry(struct ftrace_graph_ent *trace)
 208 {
 209         struct trace_array *tr = graph_array;
 210         struct trace_array_cpu *data;
 211         unsigned long flags;
 212         long disabled;
 213         int ret;
 214         int cpu;
 215         int pc;
 216
 217         if (!ftrace_trace_task(current))
 218                 return 0;
 219
 220         /* trace it when it is-nested-in or is a function enabled. */
 221         if (!(trace->depth || ftrace_graph_addr(trace->func)))
 222                 return 0;
 223
 224         local_irq_save(flags);
 225         cpu = raw_smp_processor_id();
 226         data = tr->data[cpu];
 227         disabled = atomic_inc_return(&data->disabled);
 228         if (likely(disabled == 1)) {
 229                 pc = preempt_count();
 230                 ret = __trace_graph_entry(tr, trace, flags, pc);
 231         } else {
 232                 ret = 0;
 233         }
 234
 235         atomic_dec(&data->disabled);
 236         local_irq_restore(flags);
 237
 238         return ret;
 239 }
 240
 241 int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
 242 {
 243         if (tracing_thresh)
 244                 return 1;
 245         else
 246                 return trace_graph_entry(trace);
 247 }
 248
 249 void __trace_graph_return(struct trace_array *tr,
 250                                 struct ftrace_graph_ret *trace,
 251                                 unsigned long flags,
 252                                 int pc)
 253 {
 254         struct ftrace_event_call *call = &event_funcgraph_exit;
 255         struct ring_buffer_event *event;
 256         struct ring_buffer *buffer = tr->buffer;
 257         struct ftrace_graph_ret_entry *entry;
 258
 259         if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
 260                 return;
 261
 262         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
 263                                           sizeof(*entry), flags, pc);
 264         if (!event)
 265                 return;
 266         entry   = ring_buffer_event_data(event);
 267         entry->ret                              = *trace;
 268         if (!filter_current_check_discard(buffer, call, entry, event))
 269                 ring_buffer_unlock_commit(buffer, event);
 270 }
 271
 272 void trace_graph_return(struct ftrace_graph_ret *trace)
 273 {
 274         struct trace_array *tr = graph_array;
 275         struct trace_array_cpu *data;
 276         unsigned long flags;
 277         long disabled;
 278         int cpu;
 279         int pc;
 280
 281         local_irq_save(flags);
 282         cpu = raw_smp_processor_id();
 283         data = tr->data[cpu];
 284         disabled = atomic_inc_return(&data->disabled);
 285         if (likely(disabled == 1)) {
 286                 pc = preempt_count();
 287                 __trace_graph_return(tr, trace, flags, pc);
 288         }
 289         atomic_dec(&data->disabled);
 290         local_irq_restore(flags);
 291 }
 292
 293 void set_graph_array(struct trace_array *tr)
 294 {
 295         graph_array = tr;
 296
 297         /* Make graph_array visible before we start tracing */
 298
 299         smp_mb();
 300 }
 301
 302 void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 303 {
 304         if (tracing_thresh &&
 305             (trace->rettime - trace->calltime < tracing_thresh))
 306                 return;
 307         else
 308                 trace_graph_return(trace);
 309 }
 310
 311 static int graph_trace_init(struct trace_array *tr)
 312 {
 313         int ret;
 314
 315         set_graph_array(tr);
 316         if (tracing_thresh)
 317                 ret = register_ftrace_graph(&trace_graph_thresh_return,
 318                                             &trace_graph_thresh_entry);
 319         else
 320                 ret = register_ftrace_graph(&trace_graph_return,
 321                                             &trace_graph_entry);
 322         if (ret)
 323                 return ret;
 324         tracing_start_cmdline_record();
 325
 326         return 0;
 327 }
 328
 329 static void graph_trace_reset(struct trace_array *tr)
 330 {
 331         tracing_stop_cmdline_record();
 332         unregister_ftrace_graph();
 333 }
 334
 335 static int max_bytes_for_cpu;
 336
 337 static enum print_line_t
 338 print_graph_cpu(struct trace_seq *s, int cpu)
 339 {
 340         int ret;
 341
 342         /*
 343          * Start with a space character - to make it stand out
 344          * to the right a bit when trace output is pasted into
 345          * email:
 346          */
 347         ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 348         if (!ret)
 349                 return TRACE_TYPE_PARTIAL_LINE;
 350
 351         return TRACE_TYPE_HANDLED;
 352 }
 353
 354 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 355
 356 static enum print_line_t
 357 print_graph_proc(struct trace_seq *s, pid_t pid)
 358 {
 359         char comm[TASK_COMM_LEN];
 360         /* sign + log10(MAX_INT) + '\0' */
 361         char pid_str[11];
 362         int spaces = 0;
 363         int ret;
 364         int len;
 365         int i;
 366
 367         trace_find_cmdline(pid, comm);
 368         comm[7] = '\0';
 369         sprintf(pid_str, "%d", pid);
 370
 371         /* 1 stands for the "-" character */
 372         len = strlen(comm) + strlen(pid_str) + 1;
 373
 374         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 375                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 376
 377         /* First spaces to align center */
 378         for (i = 0; i < spaces / 2; i++) {
 379                 ret = trace_seq_printf(s, " ");
 380                 if (!ret)
 381                         return TRACE_TYPE_PARTIAL_LINE;
 382         }
 383
 384         ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
 385         if (!ret)
 386                 return TRACE_TYPE_PARTIAL_LINE;
 387
 388         /* Last spaces to align center */
 389         for (i = 0; i < spaces - (spaces / 2); i++) {
 390                 ret = trace_seq_printf(s, " ");
 391                 if (!ret)
 392                         return TRACE_TYPE_PARTIAL_LINE;
 393         }
 394         return TRACE_TYPE_HANDLED;
 395 }
 396
 397
 398 static enum print_line_t
 399 print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 400 {
 401         if (!trace_seq_putc(s, ' '))
 402                 return 0;
 403
 404         return trace_print_lat_fmt(s, entry);
 405 }
 406
 407 /* If the pid changed since the last trace, output this event */
 408 static enum print_line_t
 409 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 410 {
 411         pid_t prev_pid;
 412         pid_t *last_pid;
 413         int ret;
 414
 415         if (!data)
 416                 return TRACE_TYPE_HANDLED;
 417
 418         last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
 419
 420         if (*last_pid == pid)
 421                 return TRACE_TYPE_HANDLED;
 422
 423         prev_pid = *last_pid;
 424         *last_pid = pid;
 425
 426         if (prev_pid == -1)
 427                 return TRACE_TYPE_HANDLED;
 428 /*
 429  * Context-switch trace line:
 430
 431  ------------------------------------------
 432  | 1)  migration/0--1  =>  sshd-1755
 433  ------------------------------------------
 434
 435  */
 436         ret = trace_seq_printf(s,
 437                 " ------------------------------------------\n");
 438         if (!ret)
 439                 return TRACE_TYPE_PARTIAL_LINE;
 440
 441         ret = print_graph_cpu(s, cpu);
 442         if (ret == TRACE_TYPE_PARTIAL_LINE)
 443                 return TRACE_TYPE_PARTIAL_LINE;
 444
 445         ret = print_graph_proc(s, prev_pid);
 446         if (ret == TRACE_TYPE_PARTIAL_LINE)
 447                 return TRACE_TYPE_PARTIAL_LINE;
 448
 449         ret = trace_seq_printf(s, " => ");
 450         if (!ret)
 451                 return TRACE_TYPE_PARTIAL_LINE;
 452
 453         ret = print_graph_proc(s, pid);
 454         if (ret == TRACE_TYPE_PARTIAL_LINE)
 455                 return TRACE_TYPE_PARTIAL_LINE;
 456
 457         ret = trace_seq_printf(s,
 458                 "\n ------------------------------------------\n\n");
 459         if (!ret)
 460                 return TRACE_TYPE_PARTIAL_LINE;
 461
 462         return TRACE_TYPE_HANDLED;
 463 }
 464
 465 static struct ftrace_graph_ret_entry *
 466 get_return_for_leaf(struct trace_iterator *iter,
 467                 struct ftrace_graph_ent_entry *curr)
 468 {
 469         struct fgraph_data *data = iter->private;
 470         struct ring_buffer_iter *ring_iter = NULL;
 471         struct ring_buffer_event *event;
 472         struct ftrace_graph_ret_entry *next;
 473
 474         /*
 475          * If the previous output failed to write to the seq buffer,
 476          * then we just reuse the data from before.
 477          */
 478         if (data && data->failed) {
 479                 curr = &data->ent;
 480                 next = &data->ret;
 481         } else {
 482
 483                 ring_iter = iter->buffer_iter[iter->cpu];
 484
 485                 /* First peek to compare current entry and the next one */
 486                 if (ring_iter)
 487                         event = ring_buffer_iter_peek(ring_iter, NULL);
 488                 else {
 489                         /*
 490                          * We need to consume the current entry to see
 491                          * the next one.
 492                          */
 493                         ring_buffer_consume(iter->tr->buffer, iter->cpu,
 494                                             NULL, NULL);
 495                         event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
 496                                                  NULL, NULL);
 497                 }
 498
 499                 if (!event)
 500                         return NULL;
 501
 502                 next = ring_buffer_event_data(event);
 503
 504                 if (data) {
 505                         /*
 506                          * Save current and next entries for later reference
 507                          * if the output fails.
 508                          */
 509                         data->ent = *curr;
 510                         data->ret = *next;
 511                 }
 512         }
 513
 514         if (next->ent.type != TRACE_GRAPH_RET)
 515                 return NULL;
 516
 517         if (curr->ent.pid != next->ent.pid ||
 518                         curr->graph_ent.func != next->ret.func)
 519                 return NULL;
 520
 521         /* this is a leaf, now advance the iterator */
 522         if (ring_iter)
 523                 ring_buffer_read(ring_iter, NULL);
 524
 525         return next;
 526 }
 527
 528 /* Signal a overhead of time execution to the output */
 529 static int
 530 print_graph_overhead(unsigned long long duration, struct trace_seq *s,
 531                      u32 flags)
 532 {
 533         /* If duration disappear, we don't need anything */
 534         if (!(flags & TRACE_GRAPH_PRINT_DURATION))
 535                 return 1;
 536
 537         /* Non nested entry or return */
 538         if (duration == -1)
 539                 return trace_seq_printf(s, "  ");
 540
 541         if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
 542                 /* Duration exceeded 100 msecs */
 543                 if (duration > 100000ULL)
 544                         return trace_seq_printf(s, "! ");
 545
 546                 /* Duration exceeded 10 msecs */
 547                 if (duration > 10000ULL)
 548                         return trace_seq_printf(s, "+ ");
 549         }
 550
 551         return trace_seq_printf(s, "  ");
 552 }
 553
 554 static int print_graph_abs_time(u64 t, struct trace_seq *s)
 555 {
 556         unsigned long usecs_rem;
 557
 558         usecs_rem = do_div(t, NSEC_PER_SEC);
 559         usecs_rem /= 1000;
 560
 561         return trace_seq_printf(s, "%5lu.%06lu |  ",
 562                         (unsigned long)t, usecs_rem);
 563 }
 564
 565 static enum print_line_t
 566 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 567                 enum trace_type type, int cpu, pid_t pid, u32 flags)
 568 {
 569         int ret;
 570         struct trace_seq *s = &iter->seq;
 571
 572         if (addr < (unsigned long)__irqentry_text_start ||
 573                 addr >= (unsigned long)__irqentry_text_end)
 574                 return TRACE_TYPE_UNHANDLED;
 575
 576         /* Absolute time */
 577         if (flags & 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 (flags & 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 (flags & TRACE_GRAPH_PRINT_PROC) {
 592                 ret = print_graph_proc(s, pid);
 593                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 594                         return TRACE_TYPE_PARTIAL_LINE;
 595                 ret = trace_seq_printf(s, " | ");
 596                 if (!ret)
 597                         return TRACE_TYPE_PARTIAL_LINE;
 598         }
 599
 600         /* No overhead */
 601         ret = print_graph_overhead(-1, s, flags);
 602         if (!ret)
 603                 return TRACE_TYPE_PARTIAL_LINE;
 604
 605         if (type == TRACE_GRAPH_ENT)
 606                 ret = trace_seq_printf(s, "==========>");
 607         else
 608                 ret = trace_seq_printf(s, "<==========");
 609
 610         if (!ret)
 611                 return TRACE_TYPE_PARTIAL_LINE;
 612
 613         /* Don't close the duration column if haven't one */
 614         if (flags & TRACE_GRAPH_PRINT_DURATION)
 615                 trace_seq_printf(s, " |");
 616         ret = trace_seq_printf(s, "\n");
 617
 618         if (!ret)
 619                 return TRACE_TYPE_PARTIAL_LINE;
 620         return TRACE_TYPE_HANDLED;
 621 }
 622
 623 enum print_line_t
 624 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 625 {
 626         unsigned long nsecs_rem = do_div(duration, 1000);
 627         /* log10(ULONG_MAX) + '\0' */
 628         char msecs_str[21];
 629         char nsecs_str[5];
 630         int ret, len;
 631         int i;
 632
 633         sprintf(msecs_str, "%lu", (unsigned long) duration);
 634
 635         /* Print msecs */
 636         ret = trace_seq_printf(s, "%s", msecs_str);
 637         if (!ret)
 638                 return TRACE_TYPE_PARTIAL_LINE;
 639
 640         len = strlen(msecs_str);
 641
 642         /* Print nsecs (we don't want to exceed 7 numbers) */
 643         if (len < 7) {
 644                 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
 645                 ret = trace_seq_printf(s, ".%s", nsecs_str);
 646                 if (!ret)
 647                         return TRACE_TYPE_PARTIAL_LINE;
 648                 len += strlen(nsecs_str);
 649         }
 650
 651         ret = trace_seq_printf(s, " us ");
 652         if (!ret)
 653                 return TRACE_TYPE_PARTIAL_LINE;
 654
 655         /* Print remaining spaces to fit the row's width */
 656         for (i = len; i < 7; i++) {
 657                 ret = trace_seq_printf(s, " ");
 658                 if (!ret)
 659                         return TRACE_TYPE_PARTIAL_LINE;
 660         }
 661         return TRACE_TYPE_HANDLED;
 662 }
 663
 664 static enum print_line_t
 665 print_graph_duration(unsigned long long duration, struct trace_seq *s)
 666 {
 667         int ret;
 668
 669         ret = trace_print_graph_duration(duration, s);
 670         if (ret != TRACE_TYPE_HANDLED)
 671                 return ret;
 672
 673         ret = trace_seq_printf(s, "|  ");
 674         if (!ret)
 675                 return TRACE_TYPE_PARTIAL_LINE;
 676
 677         return TRACE_TYPE_HANDLED;
 678 }
 679
 680 /* Case of a leaf function on its call entry */
 681 static enum print_line_t
 682 print_graph_entry_leaf(struct trace_iterator *iter,
 683                 struct ftrace_graph_ent_entry *entry,
 684                 struct ftrace_graph_ret_entry *ret_entry,
 685                 struct trace_seq *s, u32 flags)
 686 {
 687         struct fgraph_data *data = iter->private;
 688         struct ftrace_graph_ret *graph_ret;
 689         struct ftrace_graph_ent *call;
 690         unsigned long long duration;
 691         int ret;
 692         int i;
 693
 694         graph_ret = &ret_entry->ret;
 695         call = &entry->graph_ent;
 696         duration = graph_ret->rettime - graph_ret->calltime;
 697
 698         if (data) {
 699                 struct fgraph_cpu_data *cpu_data;
 700                 int cpu = iter->cpu;
 701
 702                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 703
 704                 /*
 705                  * Comments display at + 1 to depth. Since
 706                  * this is a leaf function, keep the comments
 707                  * equal to this depth.
 708                  */
 709                 cpu_data->depth = call->depth - 1;
 710
 711                 /* No need to keep this function around for this depth */
 712                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 713                         cpu_data->enter_funcs[call->depth] = 0;
 714         }
 715
 716         /* Overhead */
 717         ret = print_graph_overhead(duration, s, flags);
 718         if (!ret)
 719                 return TRACE_TYPE_PARTIAL_LINE;
 720
 721         /* Duration */
 722         if (flags & TRACE_GRAPH_PRINT_DURATION) {
 723                 ret = print_graph_duration(duration, s);
 724                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 725                         return TRACE_TYPE_PARTIAL_LINE;
 726         }
 727
 728         /* Function */
 729         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 730                 ret = trace_seq_printf(s, " ");
 731                 if (!ret)
 732                         return TRACE_TYPE_PARTIAL_LINE;
 733         }
 734
 735         ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
 736         if (!ret)
 737                 return TRACE_TYPE_PARTIAL_LINE;
 738
 739         return TRACE_TYPE_HANDLED;
 740 }
 741
 742 static enum print_line_t
 743 print_graph_entry_nested(struct trace_iterator *iter,
 744                          struct ftrace_graph_ent_entry *entry,
 745                          struct trace_seq *s, int cpu, u32 flags)
 746 {
 747         struct ftrace_graph_ent *call = &entry->graph_ent;
 748         struct fgraph_data *data = iter->private;
 749         int ret;
 750         int i;
 751
 752         if (data) {
 753                 struct fgraph_cpu_data *cpu_data;
 754                 int cpu = iter->cpu;
 755
 756                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 757                 cpu_data->depth = call->depth;
 758
 759                 /* Save this function pointer to see if the exit matches */
 760                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 761                         cpu_data->enter_funcs[call->depth] = call->func;
 762         }
 763
 764         /* No overhead */
 765         ret = print_graph_overhead(-1, s, flags);
 766         if (!ret)
 767                 return TRACE_TYPE_PARTIAL_LINE;
 768
 769         /* No time */
 770         if (flags & TRACE_GRAPH_PRINT_DURATION) {
 771                 ret = trace_seq_printf(s, "            |  ");
 772                 if (!ret)
 773                         return TRACE_TYPE_PARTIAL_LINE;
 774         }
 775
 776         /* Function */
 777         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 778                 ret = trace_seq_printf(s, " ");
 779                 if (!ret)
 780                         return TRACE_TYPE_PARTIAL_LINE;
 781         }
 782
 783         ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
 784         if (!ret)
 785                 return TRACE_TYPE_PARTIAL_LINE;
 786
 787         /*
 788          * we already consumed the current entry to check the next one
 789          * and see if this is a leaf.
 790          */
 791         return TRACE_TYPE_NO_CONSUME;
 792 }
 793
 794 static enum print_line_t
 795 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 796                      int type, unsigned long addr, u32 flags)
 797 {
 798         struct fgraph_data *data = iter->private;
 799         struct trace_entry *ent = iter->ent;
 800         int cpu = iter->cpu;
 801         int ret;
 802
 803         /* Pid */
 804         if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
 805                 return TRACE_TYPE_PARTIAL_LINE;
 806
 807         if (type) {
 808                 /* Interrupt */
 809                 ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
 810                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 811                         return TRACE_TYPE_PARTIAL_LINE;
 812         }
 813
 814         /* Absolute time */
 815         if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
 816                 ret = print_graph_abs_time(iter->ts, s);
 817                 if (!ret)
 818                         return TRACE_TYPE_PARTIAL_LINE;
 819         }
 820
 821         /* Cpu */
 822         if (flags & TRACE_GRAPH_PRINT_CPU) {
 823                 ret = print_graph_cpu(s, cpu);
 824                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 825                         return TRACE_TYPE_PARTIAL_LINE;
 826         }
 827
 828         /* Proc */
 829         if (flags & TRACE_GRAPH_PRINT_PROC) {
 830                 ret = print_graph_proc(s, ent->pid);
 831                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 832                         return TRACE_TYPE_PARTIAL_LINE;
 833
 834                 ret = trace_seq_printf(s, " | ");
 835                 if (!ret)
 836                         return TRACE_TYPE_PARTIAL_LINE;
 837         }
 838
 839         /* Latency format */
 840         if (trace_flags & TRACE_ITER_LATENCY_FMT) {
 841                 ret = print_graph_lat_fmt(s, ent);
 842                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 843                         return TRACE_TYPE_PARTIAL_LINE;
 844         }
 845
 846         return 0;
 847 }
 848
 849 static enum print_line_t
 850 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 851                         struct trace_iterator *iter, u32 flags)
 852 {
 853         struct fgraph_data *data = iter->private;
 854         struct ftrace_graph_ent *call = &field->graph_ent;
 855         struct ftrace_graph_ret_entry *leaf_ret;
 856         static enum print_line_t ret;
 857         int cpu = iter->cpu;
 858
 859         if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
 860                 return TRACE_TYPE_PARTIAL_LINE;
 861
 862         leaf_ret = get_return_for_leaf(iter, field);
 863         if (leaf_ret)
 864                 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
 865         else
 866                 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
 867
 868         if (data) {
 869                 /*
 870                  * If we failed to write our output, then we need to make
 871                  * note of it. Because we already consumed our entry.
 872                  */
 873                 if (s->full) {
 874                         data->failed = 1;
 875                         data->cpu = cpu;
 876                 } else
 877                         data->failed = 0;
 878         }
 879
 880         return ret;
 881 }
 882
 883 static enum print_line_t
 884 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 885                    struct trace_entry *ent, struct trace_iterator *iter,
 886                    u32 flags)
 887 {
 888         unsigned long long duration = trace->rettime - trace->calltime;
 889         struct fgraph_data *data = iter->private;
 890         pid_t pid = ent->pid;
 891         int cpu = iter->cpu;
 892         int func_match = 1;
 893         int ret;
 894         int i;
 895
 896         if (data) {
 897                 struct fgraph_cpu_data *cpu_data;
 898                 int cpu = iter->cpu;
 899
 900                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 901
 902                 /*
 903                  * Comments display at + 1 to depth. This is the
 904                  * return from a function, we now want the comments
 905                  * to display at the same level of the bracket.
 906                  */
 907                 cpu_data->depth = trace->depth - 1;
 908
 909                 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
 910                         if (cpu_data->enter_funcs[trace->depth] != trace->func)
 911                                 func_match = 0;
 912                         cpu_data->enter_funcs[trace->depth] = 0;
 913                 }
 914         }
 915
 916         if (print_graph_prologue(iter, s, 0, 0, flags))
 917                 return TRACE_TYPE_PARTIAL_LINE;
 918
 919         /* Overhead */
 920         ret = print_graph_overhead(duration, s, flags);
 921         if (!ret)
 922                 return TRACE_TYPE_PARTIAL_LINE;
 923
 924         /* Duration */
 925         if (flags & TRACE_GRAPH_PRINT_DURATION) {
 926                 ret = print_graph_duration(duration, s);
 927                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 928                         return TRACE_TYPE_PARTIAL_LINE;
 929         }
 930
 931         /* Closing brace */
 932         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
 933                 ret = trace_seq_printf(s, " ");
 934                 if (!ret)
 935                         return TRACE_TYPE_PARTIAL_LINE;
 936         }
 937
 938         /*
 939          * If the return function does not have a matching entry,
 940          * then the entry was lost. Instead of just printing
 941          * the '}' and letting the user guess what function this
 942          * belongs to, write out the function name.
 943          */
 944         if (func_match) {
 945                 ret = trace_seq_printf(s, "}\n");
 946                 if (!ret)
 947                         return TRACE_TYPE_PARTIAL_LINE;
 948         } else {
 949                 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
 950                 if (!ret)
 951                         return TRACE_TYPE_PARTIAL_LINE;
 952         }
 953
 954         /* Overrun */
 955         if (flags & TRACE_GRAPH_PRINT_OVERRUN) {
 956                 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
 957                                         trace->overrun);
 958                 if (!ret)
 959                         return TRACE_TYPE_PARTIAL_LINE;
 960         }
 961
 962         ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
 963                               cpu, pid, flags);
 964         if (ret == TRACE_TYPE_PARTIAL_LINE)
 965                 return TRACE_TYPE_PARTIAL_LINE;
 966
 967         return TRACE_TYPE_HANDLED;
 968 }
 969
 970 static enum print_line_t
 971 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
 972                     struct trace_iterator *iter, u32 flags)
 973 {
 974         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
 975         struct fgraph_data *data = iter->private;
 976         struct trace_event *event;
 977         int depth = 0;
 978         int ret;
 979         int i;
 980
 981         if (data)
 982                 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
 983
 984         if (print_graph_prologue(iter, s, 0, 0, flags))
 985                 return TRACE_TYPE_PARTIAL_LINE;
 986
 987         /* No overhead */
 988         ret = print_graph_overhead(-1, s, flags);
 989         if (!ret)
 990                 return TRACE_TYPE_PARTIAL_LINE;
 991
 992         /* No time */
 993         if (flags & TRACE_GRAPH_PRINT_DURATION) {
 994                 ret = trace_seq_printf(s, "            |  ");
 995                 if (!ret)
 996                         return TRACE_TYPE_PARTIAL_LINE;
 997         }
 998
 999         /* Indentation */
1000         if (depth > 0)
1001                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
1002                         ret = trace_seq_printf(s, " ");
1003                         if (!ret)
1004                                 return TRACE_TYPE_PARTIAL_LINE;
1005                 }
1006
1007         /* The comment */
1008         ret = trace_seq_printf(s, "/* ");
1009         if (!ret)
1010                 return TRACE_TYPE_PARTIAL_LINE;
1011
1012         switch (iter->ent->type) {
1013         case TRACE_BPRINT:
1014                 ret = trace_print_bprintk_msg_only(iter);
1015                 if (ret != TRACE_TYPE_HANDLED)
1016                         return ret;
1017                 break;
1018         case TRACE_PRINT:
1019                 ret = trace_print_printk_msg_only(iter);
1020                 if (ret != TRACE_TYPE_HANDLED)
1021                         return ret;
1022                 break;
1023         default:
1024                 event = ftrace_find_event(ent->type);
1025                 if (!event)
1026                         return TRACE_TYPE_UNHANDLED;
1027
1028                 ret = event->funcs->trace(iter, sym_flags, event);
1029                 if (ret != TRACE_TYPE_HANDLED)
1030                         return ret;
1031         }
1032
1033         /* Strip ending newline */
1034         if (s->buffer[s->len - 1] == '\n') {
1035                 s->buffer[s->len - 1] = '\0';
1036                 s->len--;
1037         }
1038
1039         ret = trace_seq_printf(s, " */\n");
1040         if (!ret)
1041                 return TRACE_TYPE_PARTIAL_LINE;
1042
1043         return TRACE_TYPE_HANDLED;
1044 }
1045
1046
1047 enum print_line_t
1048 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1049 {
1050         struct ftrace_graph_ent_entry *field;
1051         struct fgraph_data *data = iter->private;
1052         struct trace_entry *entry = iter->ent;
1053         struct trace_seq *s = &iter->seq;
1054         int cpu = iter->cpu;
1055         int ret;
1056
1057         if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1058                 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1059                 return TRACE_TYPE_HANDLED;
1060         }
1061
1062         /*
1063          * If the last output failed, there's a possibility we need
1064          * to print out the missing entry which would never go out.
1065          */
1066         if (data && data->failed) {
1067                 field = &data->ent;
1068                 iter->cpu = data->cpu;
1069                 ret = print_graph_entry(field, s, iter, flags);
1070                 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1071                         per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1072                         ret = TRACE_TYPE_NO_CONSUME;
1073                 }
1074                 iter->cpu = cpu;
1075                 return ret;
1076         }
1077
1078         switch (entry->type) {
1079         case TRACE_GRAPH_ENT: {
1080                 /*
1081                  * print_graph_entry() may consume the current event,
1082                  * thus @field may become invalid, so we need to save it.
1083                  * sizeof(struct ftrace_graph_ent_entry) is very small,
1084                  * it can be safely saved at the stack.
1085                  */
1086                 struct ftrace_graph_ent_entry saved;
1087                 trace_assign_type(field, entry);
1088                 saved = *field;
1089                 return print_graph_entry(&saved, s, iter, flags);
1090         }
1091         case TRACE_GRAPH_RET: {
1092                 struct ftrace_graph_ret_entry *field;
1093                 trace_assign_type(field, entry);
1094                 return print_graph_return(&field->ret, s, entry, iter, flags);
1095         }
1096         case TRACE_STACK:
1097         case TRACE_FN:
1098                 /* dont trace stack and functions as comments */
1099                 return TRACE_TYPE_UNHANDLED;
1100
1101         default:
1102                 return print_graph_comment(s, entry, iter, flags);
1103         }
1104
1105         return TRACE_TYPE_HANDLED;
1106 }
1107
1108 static enum print_line_t
1109 print_graph_function(struct trace_iterator *iter)
1110 {
1111         return print_graph_function_flags(iter, tracer_flags.val);
1112 }
1113
1114 static enum print_line_t
1115 print_graph_function_event(struct trace_iterator *iter, int flags,
1116                            struct trace_event *event)
1117 {
1118         return print_graph_function(iter);
1119 }
1120
1121 static void print_lat_header(struct seq_file *s, u32 flags)
1122 {
1123         static const char spaces[] = "                " /* 16 spaces */
1124                 "    "                                  /* 4 spaces */
1125                 "                 ";                    /* 17 spaces */
1126         int size = 0;
1127
1128         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1129                 size += 16;
1130         if (flags & TRACE_GRAPH_PRINT_CPU)
1131                 size += 4;
1132         if (flags & TRACE_GRAPH_PRINT_PROC)
1133                 size += 17;
1134
1135         seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
1136         seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
1137         seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1138         seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
1139         seq_printf(s, "#%.*s||| / _-=> lock-depth      \n", size, spaces);
1140         seq_printf(s, "#%.*s|||| /                     \n", size, spaces);
1141 }
1142
1143 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1144 {
1145         int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1146
1147         if (lat)
1148                 print_lat_header(s, flags);
1149
1150         /* 1st line */
1151         seq_printf(s, "#");
1152         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1153                 seq_printf(s, "     TIME       ");
1154         if (flags & TRACE_GRAPH_PRINT_CPU)
1155                 seq_printf(s, " CPU");
1156         if (flags & TRACE_GRAPH_PRINT_PROC)
1157                 seq_printf(s, "  TASK/PID       ");
1158         if (lat)
1159                 seq_printf(s, "|||||");
1160         if (flags & TRACE_GRAPH_PRINT_DURATION)
1161                 seq_printf(s, "  DURATION   ");
1162         seq_printf(s, "               FUNCTION CALLS\n");
1163
1164         /* 2nd line */
1165         seq_printf(s, "#");
1166         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1167                 seq_printf(s, "      |         ");
1168         if (flags & TRACE_GRAPH_PRINT_CPU)
1169                 seq_printf(s, " |  ");
1170         if (flags & TRACE_GRAPH_PRINT_PROC)
1171                 seq_printf(s, "   |    |        ");
1172         if (lat)
1173                 seq_printf(s, "|||||");
1174         if (flags & TRACE_GRAPH_PRINT_DURATION)
1175                 seq_printf(s, "   |   |      ");
1176         seq_printf(s, "               |   |   |   |\n");
1177 }
1178
1179 void print_graph_headers(struct seq_file *s)
1180 {
1181         print_graph_headers_flags(s, tracer_flags.val);
1182 }
1183
1184 void graph_trace_open(struct trace_iterator *iter)
1185 {
1186         /* pid and depth on the last trace processed */
1187         struct fgraph_data *data;
1188         int cpu;
1189
1190         iter->private = NULL;
1191
1192         data = kzalloc(sizeof(*data), GFP_KERNEL);
1193         if (!data)
1194                 goto out_err;
1195
1196         data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
1197         if (!data->cpu_data)
1198                 goto out_err_free;
1199
1200         for_each_possible_cpu(cpu) {
1201                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1202                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1203                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1204                 *pid = -1;
1205                 *depth = 0;
1206                 *ignore = 0;
1207         }
1208
1209         iter->private = data;
1210
1211         return;
1212
1213  out_err_free:
1214         kfree(data);
1215  out_err:
1216         pr_warning("function graph tracer: not enough memory\n");
1217 }
1218
1219 void graph_trace_close(struct trace_iterator *iter)
1220 {
1221         struct fgraph_data *data = iter->private;
1222
1223         if (data) {
1224                 free_percpu(data->cpu_data);
1225                 kfree(data);
1226         }
1227 }
1228
1229 static struct trace_event_functions graph_functions = {
1230         .trace          = print_graph_function_event,
1231 };
1232
1233 static struct trace_event graph_trace_entry_event = {
1234         .type           = TRACE_GRAPH_ENT,
1235         .funcs          = &graph_functions,
1236 };
1237
1238 static struct trace_event graph_trace_ret_event = {
1239         .type           = TRACE_GRAPH_RET,
1240         .funcs          = &graph_functions
1241 };
1242
1243 static struct tracer graph_trace __read_mostly = {
1244         .name           = "function_graph",
1245         .open           = graph_trace_open,
1246         .pipe_open      = graph_trace_open,
1247         .close          = graph_trace_close,
1248         .pipe_close     = graph_trace_close,
1249         .wait_pipe      = poll_wait_pipe,
1250         .init           = graph_trace_init,
1251         .reset          = graph_trace_reset,
1252         .print_line     = print_graph_function,
1253         .print_header   = print_graph_headers,
1254         .flags          = &tracer_flags,
1255 #ifdef CONFIG_FTRACE_SELFTEST
1256         .selftest       = trace_selftest_startup_function_graph,
1257 #endif
1258 };
1259
1260 static __init int init_graph_trace(void)
1261 {
1262         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1263
1264         if (!register_ftrace_event(&graph_trace_entry_event)) {
1265                 pr_warning("Warning: could not register graph trace events\n");
1266                 return 1;
1267         }
1268
1269         if (!register_ftrace_event(&graph_trace_ret_event)) {
1270                 pr_warning("Warning: could not register graph trace events\n");
1271                 return 1;
1272         }
1273
1274         return register_tracer(&graph_trace);
1275 }
1276
1277 device_initcall(init_graph_trace);