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 /* When set, irq functions will be ignored */
  19 static int ftrace_graph_skip_irqs;
  20
  21 struct fgraph_cpu_data {
  22         pid_t           last_pid;
  23         int             depth;
  24         int             depth_irq;
  25         int             ignore;
  26         unsigned long   enter_funcs[FTRACE_RETFUNC_DEPTH];
  27 };
  28
  29 struct fgraph_data {
  30         struct fgraph_cpu_data __percpu *cpu_data;
  31
  32         /* Place to preserve last processed entry. */
  33         struct ftrace_graph_ent_entry   ent;
  34         struct ftrace_graph_ret_entry   ret;
  35         int                             failed;
  36         int                             cpu;
  37 };
  38
  39 #define TRACE_GRAPH_INDENT      2
  40
  41 /* Flag options */
  42 #define TRACE_GRAPH_PRINT_OVERRUN       0x1
  43 #define TRACE_GRAPH_PRINT_CPU           0x2
  44 #define TRACE_GRAPH_PRINT_OVERHEAD      0x4
  45 #define TRACE_GRAPH_PRINT_PROC          0x8
  46 #define TRACE_GRAPH_PRINT_DURATION      0x10
  47 #define TRACE_GRAPH_PRINT_ABS_TIME      0x20
  48 #define TRACE_GRAPH_PRINT_IRQS          0x40
  49 #define TRACE_GRAPH_PRINT_FLAT          0x80
  50
  51
  52 static unsigned int max_depth;
  53
  54 static struct tracer_opt trace_opts[] = {
  55         /* Display overruns? (for self-debug purpose) */
  56         { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
  57         /* Display CPU ? */
  58         { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
  59         /* Display Overhead ? */
  60         { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
  61         /* Display proc name/pid */
  62         { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
  63         /* Display duration of execution */
  64         { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
  65         /* Display absolute time of an entry */
  66         { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
  67         /* Display interrupts */
  68         { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
  69         /* Use standard trace formatting rather than hierarchical */
  70         { TRACER_OPT(funcgraph-flat, TRACE_GRAPH_PRINT_FLAT) },
  71         { } /* Empty entry */
  72 };
  73
  74 static struct tracer_flags tracer_flags = {
  75         /* Don't display overruns and proc by default */
  76         .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
  77                TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS,
  78         .opts = trace_opts
  79 };
  80
  81 static struct trace_array *graph_array;
  82
  83 /*
  84  * DURATION column is being also used to display IRQ signs,
  85  * following values are used by print_graph_irq and others
  86  * to fill in space into DURATION column.
  87  */
  88 enum {
  89         DURATION_FILL_FULL  = -1,
  90         DURATION_FILL_START = -2,
  91         DURATION_FILL_END   = -3,
  92 };
  93
  94 static enum print_line_t
  95 print_graph_duration(unsigned long long duration, struct trace_seq *s,
  96                      u32 flags);
  97
  98 /* Add a function return address to the trace stack on thread info.*/
  99 int
 100 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 101                          unsigned long frame_pointer)
 102 {
 103         unsigned long long calltime;
 104         int index;
 105
 106         if (!current->ret_stack)
 107                 return -EBUSY;
 108
 109         /*
 110          * We must make sure the ret_stack is tested before we read
 111          * anything else.
 112          */
 113         smp_rmb();
 114
 115         /* The return trace stack is full */
 116         if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
 117                 atomic_inc(&current->trace_overrun);
 118                 return -EBUSY;
 119         }
 120
 121         calltime = trace_clock_local();
 122
 123         index = ++current->curr_ret_stack;
 124         barrier();
 125         current->ret_stack[index].ret = ret;
 126         current->ret_stack[index].func = func;
 127         current->ret_stack[index].calltime = calltime;
 128         current->ret_stack[index].subtime = 0;
 129         current->ret_stack[index].fp = frame_pointer;
 130         *depth = index;
 131
 132         return 0;
 133 }
 134
 135 /* Retrieve a function return address to the trace stack on thread info.*/
 136 static void
 137 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
 138                         unsigned long frame_pointer)
 139 {
 140         int index;
 141
 142         index = current->curr_ret_stack;
 143
 144         if (unlikely(index < 0)) {
 145                 ftrace_graph_stop();
 146                 WARN_ON(1);
 147                 /* Might as well panic, otherwise we have no where to go */
 148                 *ret = (unsigned long)panic;
 149                 return;
 150         }
 151
 152 #if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY)
 153         /*
 154          * The arch may choose to record the frame pointer used
 155          * and check it here to make sure that it is what we expect it
 156          * to be. If gcc does not set the place holder of the return
 157          * address in the frame pointer, and does a copy instead, then
 158          * the function graph trace will fail. This test detects this
 159          * case.
 160          *
 161          * Currently, x86_32 with optimize for size (-Os) makes the latest
 162          * gcc do the above.
 163          *
 164          * Note, -mfentry does not use frame pointers, and this test
 165          *  is not needed if CC_USING_FENTRY is set.
 166          */
 167         if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
 168                 ftrace_graph_stop();
 169                 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
 170                      "  from func %ps return to %lx\n",
 171                      current->ret_stack[index].fp,
 172                      frame_pointer,
 173                      (void *)current->ret_stack[index].func,
 174                      current->ret_stack[index].ret);
 175                 *ret = (unsigned long)panic;
 176                 return;
 177         }
 178 #endif
 179
 180         *ret = current->ret_stack[index].ret;
 181         trace->func = current->ret_stack[index].func;
 182         trace->calltime = current->ret_stack[index].calltime;
 183         trace->overrun = atomic_read(&current->trace_overrun);
 184         trace->depth = index;
 185 }
 186
 187 /*
 188  * Send the trace to the ring-buffer.
 189  * @return the original return address.
 190  */
 191 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 192 {
 193         struct ftrace_graph_ret trace;
 194         unsigned long ret;
 195
 196         ftrace_pop_return_trace(&trace, &ret, frame_pointer);
 197         trace.rettime = trace_clock_local();
 198         barrier();
 199         current->curr_ret_stack--;
 200
 201         /*
 202          * The trace should run after decrementing the ret counter
 203          * in case an interrupt were to come in. We don't want to
 204          * lose the interrupt if max_depth is set.
 205          */
 206         ftrace_graph_return(&trace);
 207
 208         if (unlikely(!ret)) {
 209                 ftrace_graph_stop();
 210                 WARN_ON(1);
 211                 /* Might as well panic. What else to do? */
 212                 ret = (unsigned long)panic;
 213         }
 214
 215         return ret;
 216 }
 217
 218 int __trace_graph_entry(struct trace_array *tr,
 219                                 struct ftrace_graph_ent *trace,
 220                                 unsigned long flags,
 221                                 int pc)
 222 {
 223         struct ftrace_event_call *call = &event_funcgraph_entry;
 224         struct ring_buffer_event *event;
 225         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 226         struct ftrace_graph_ent_entry *entry;
 227
 228         if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
 229                 return 0;
 230
 231         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
 232                                           sizeof(*entry), flags, pc);
 233         if (!event)
 234                 return 0;
 235         entry   = ring_buffer_event_data(event);
 236         entry->graph_ent                        = *trace;
 237         if (!filter_current_check_discard(buffer, call, entry, event))
 238                 __buffer_unlock_commit(buffer, event);
 239
 240         return 1;
 241 }
 242
 243 static inline int ftrace_graph_ignore_irqs(void)
 244 {
 245         if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
 246                 return 0;
 247
 248         return in_irq();
 249 }
 250
 251 int trace_graph_entry(struct ftrace_graph_ent *trace)
 252 {
 253         struct trace_array *tr = graph_array;
 254         struct trace_array_cpu *data;
 255         unsigned long flags;
 256         long disabled;
 257         int ret;
 258         int cpu;
 259         int pc;
 260
 261         if (!ftrace_trace_task(current))
 262                 return 0;
 263
 264         /* trace it when it is-nested-in or is a function enabled. */
 265         if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
 266              ftrace_graph_ignore_irqs()) ||
 267             (max_depth && trace->depth >= max_depth))
 268                 return 0;
 269
 270         local_irq_save(flags);
 271         cpu = raw_smp_processor_id();
 272         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 273         disabled = atomic_inc_return(&data->disabled);
 274         if (likely(disabled == 1)) {
 275                 pc = preempt_count();
 276                 ret = __trace_graph_entry(tr, trace, flags, pc);
 277         } else {
 278                 ret = 0;
 279         }
 280
 281         atomic_dec(&data->disabled);
 282         local_irq_restore(flags);
 283
 284         return ret;
 285 }
 286
 287 int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
 288 {
 289         if (tracing_thresh)
 290                 return 1;
 291         else
 292                 return trace_graph_entry(trace);
 293 }
 294
 295 static void
 296 __trace_graph_function(struct trace_array *tr,
 297                 unsigned long ip, unsigned long flags, int pc)
 298 {
 299         u64 time = trace_clock_local();
 300         struct ftrace_graph_ent ent = {
 301                 .func  = ip,
 302                 .depth = 0,
 303         };
 304         struct ftrace_graph_ret ret = {
 305                 .func     = ip,
 306                 .depth    = 0,
 307                 .calltime = time,
 308                 .rettime  = time,
 309         };
 310
 311         __trace_graph_entry(tr, &ent, flags, pc);
 312         __trace_graph_return(tr, &ret, flags, pc);
 313 }
 314
 315 void
 316 trace_graph_function(struct trace_array *tr,
 317                 unsigned long ip, unsigned long parent_ip,
 318                 unsigned long flags, int pc)
 319 {
 320         __trace_graph_function(tr, ip, flags, pc);
 321 }
 322
 323 void __trace_graph_return(struct trace_array *tr,
 324                                 struct ftrace_graph_ret *trace,
 325                                 unsigned long flags,
 326                                 int pc)
 327 {
 328         struct ftrace_event_call *call = &event_funcgraph_exit;
 329         struct ring_buffer_event *event;
 330         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 331         struct ftrace_graph_ret_entry *entry;
 332
 333         if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
 334                 return;
 335
 336         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
 337                                           sizeof(*entry), flags, pc);
 338         if (!event)
 339                 return;
 340         entry   = ring_buffer_event_data(event);
 341         entry->ret                              = *trace;
 342         if (!filter_current_check_discard(buffer, call, entry, event))
 343                 __buffer_unlock_commit(buffer, event);
 344 }
 345
 346 void trace_graph_return(struct ftrace_graph_ret *trace)
 347 {
 348         struct trace_array *tr = graph_array;
 349         struct trace_array_cpu *data;
 350         unsigned long flags;
 351         long disabled;
 352         int cpu;
 353         int pc;
 354
 355         local_irq_save(flags);
 356         cpu = raw_smp_processor_id();
 357         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 358         disabled = atomic_inc_return(&data->disabled);
 359         if (likely(disabled == 1)) {
 360                 pc = preempt_count();
 361                 __trace_graph_return(tr, trace, flags, pc);
 362         }
 363         atomic_dec(&data->disabled);
 364         local_irq_restore(flags);
 365 }
 366
 367 void set_graph_array(struct trace_array *tr)
 368 {
 369         graph_array = tr;
 370
 371         /* Make graph_array visible before we start tracing */
 372
 373         smp_mb();
 374 }
 375
 376 void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 377 {
 378         if (tracing_thresh &&
 379             (trace->rettime - trace->calltime < tracing_thresh))
 380                 return;
 381         else
 382                 trace_graph_return(trace);
 383 }
 384
 385 static int graph_trace_init(struct trace_array *tr)
 386 {
 387         int ret;
 388
 389         set_graph_array(tr);
 390         if (tracing_thresh)
 391                 ret = register_ftrace_graph(&trace_graph_thresh_return,
 392                                             &trace_graph_thresh_entry);
 393         else
 394                 ret = register_ftrace_graph(&trace_graph_return,
 395                                             &trace_graph_entry);
 396         if (ret)
 397                 return ret;
 398         tracing_start_cmdline_record();
 399
 400         return 0;
 401 }
 402
 403 static void graph_trace_reset(struct trace_array *tr)
 404 {
 405         tracing_stop_cmdline_record();
 406         unregister_ftrace_graph();
 407 }
 408
 409 static int max_bytes_for_cpu;
 410
 411 static enum print_line_t
 412 print_graph_cpu(struct trace_seq *s, int cpu)
 413 {
 414         int ret;
 415
 416         /*
 417          * Start with a space character - to make it stand out
 418          * to the right a bit when trace output is pasted into
 419          * email:
 420          */
 421         ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 422         if (!ret)
 423                 return TRACE_TYPE_PARTIAL_LINE;
 424
 425         return TRACE_TYPE_HANDLED;
 426 }
 427
 428 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 429
 430 static enum print_line_t
 431 print_graph_proc(struct trace_seq *s, pid_t pid)
 432 {
 433         char comm[TASK_COMM_LEN];
 434         /* sign + log10(MAX_INT) + '\0' */
 435         char pid_str[11];
 436         int spaces = 0;
 437         int ret;
 438         int len;
 439         int i;
 440
 441         trace_find_cmdline(pid, comm);
 442         comm[7] = '\0';
 443         sprintf(pid_str, "%d", pid);
 444
 445         /* 1 stands for the "-" character */
 446         len = strlen(comm) + strlen(pid_str) + 1;
 447
 448         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 449                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 450
 451         /* First spaces to align center */
 452         for (i = 0; i < spaces / 2; i++) {
 453                 ret = trace_seq_printf(s, " ");
 454                 if (!ret)
 455                         return TRACE_TYPE_PARTIAL_LINE;
 456         }
 457
 458         ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
 459         if (!ret)
 460                 return TRACE_TYPE_PARTIAL_LINE;
 461
 462         /* Last spaces to align center */
 463         for (i = 0; i < spaces - (spaces / 2); i++) {
 464                 ret = trace_seq_printf(s, " ");
 465                 if (!ret)
 466                         return TRACE_TYPE_PARTIAL_LINE;
 467         }
 468         return TRACE_TYPE_HANDLED;
 469 }
 470
 471
 472 static enum print_line_t
 473 print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 474 {
 475         if (!trace_seq_putc(s, ' '))
 476                 return 0;
 477
 478         return trace_print_lat_fmt(s, entry);
 479 }
 480
 481 /* If the pid changed since the last trace, output this event */
 482 static enum print_line_t
 483 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 484 {
 485         pid_t prev_pid;
 486         pid_t *last_pid;
 487         int ret;
 488
 489         if (!data)
 490                 return TRACE_TYPE_HANDLED;
 491
 492         last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
 493
 494         if (*last_pid == pid)
 495                 return TRACE_TYPE_HANDLED;
 496
 497         prev_pid = *last_pid;
 498         *last_pid = pid;
 499
 500         if (prev_pid == -1)
 501                 return TRACE_TYPE_HANDLED;
 502 /*
 503  * Context-switch trace line:
 504
 505  ------------------------------------------
 506  | 1)  migration/0--1  =>  sshd-1755
 507  ------------------------------------------
 508
 509  */
 510         ret = trace_seq_printf(s,
 511                 " ------------------------------------------\n");
 512         if (!ret)
 513                 return TRACE_TYPE_PARTIAL_LINE;
 514
 515         ret = print_graph_cpu(s, cpu);
 516         if (ret == TRACE_TYPE_PARTIAL_LINE)
 517                 return TRACE_TYPE_PARTIAL_LINE;
 518
 519         ret = print_graph_proc(s, prev_pid);
 520         if (ret == TRACE_TYPE_PARTIAL_LINE)
 521                 return TRACE_TYPE_PARTIAL_LINE;
 522
 523         ret = trace_seq_printf(s, " => ");
 524         if (!ret)
 525                 return TRACE_TYPE_PARTIAL_LINE;
 526
 527         ret = print_graph_proc(s, pid);
 528         if (ret == TRACE_TYPE_PARTIAL_LINE)
 529                 return TRACE_TYPE_PARTIAL_LINE;
 530
 531         ret = trace_seq_printf(s,
 532                 "\n ------------------------------------------\n\n");
 533         if (!ret)
 534                 return TRACE_TYPE_PARTIAL_LINE;
 535
 536         return TRACE_TYPE_HANDLED;
 537 }
 538
 539 static struct ftrace_graph_ret_entry *
 540 get_return_for_leaf(struct trace_iterator *iter,
 541                 struct ftrace_graph_ent_entry *curr)
 542 {
 543         struct fgraph_data *data = iter->private;
 544         struct ring_buffer_iter *ring_iter = NULL;
 545         struct ring_buffer_event *event;
 546         struct ftrace_graph_ret_entry *next;
 547
 548         /*
 549          * If the previous output failed to write to the seq buffer,
 550          * then we just reuse the data from before.
 551          */
 552         if (data && data->failed) {
 553                 curr = &data->ent;
 554                 next = &data->ret;
 555         } else {
 556
 557                 ring_iter = trace_buffer_iter(iter, iter->cpu);
 558
 559                 /* First peek to compare current entry and the next one */
 560                 if (ring_iter)
 561                         event = ring_buffer_iter_peek(ring_iter, NULL);
 562                 else {
 563                         /*
 564                          * We need to consume the current entry to see
 565                          * the next one.
 566                          */
 567                         ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
 568                                             NULL, NULL);
 569                         event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
 570                                                  NULL, NULL);
 571                 }
 572
 573                 if (!event)
 574                         return NULL;
 575
 576                 next = ring_buffer_event_data(event);
 577
 578                 if (data) {
 579                         /*
 580                          * Save current and next entries for later reference
 581                          * if the output fails.
 582                          */
 583                         data->ent = *curr;
 584                         /*
 585                          * If the next event is not a return type, then
 586                          * we only care about what type it is. Otherwise we can
 587                          * safely copy the entire event.
 588                          */
 589                         if (next->ent.type == TRACE_GRAPH_RET)
 590                                 data->ret = *next;
 591                         else
 592                                 data->ret.ent.type = next->ent.type;
 593                 }
 594         }
 595
 596         if (next->ent.type != TRACE_GRAPH_RET)
 597                 return NULL;
 598
 599         if (curr->ent.pid != next->ent.pid ||
 600                         curr->graph_ent.func != next->ret.func)
 601                 return NULL;
 602
 603         /* this is a leaf, now advance the iterator */
 604         if (ring_iter)
 605                 ring_buffer_read(ring_iter, NULL);
 606
 607         return next;
 608 }
 609
 610 static int print_graph_abs_time(u64 t, struct trace_seq *s)
 611 {
 612         unsigned long usecs_rem;
 613
 614         usecs_rem = do_div(t, NSEC_PER_SEC);
 615         usecs_rem /= 1000;
 616
 617         return trace_seq_printf(s, "%5lu.%06lu |  ",
 618                         (unsigned long)t, usecs_rem);
 619 }
 620
 621 static enum print_line_t
 622 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 623                 enum trace_type type, int cpu, pid_t pid, u32 flags)
 624 {
 625         int ret;
 626         struct trace_seq *s = &iter->seq;
 627
 628         if (addr < (unsigned long)__irqentry_text_start ||
 629                 addr >= (unsigned long)__irqentry_text_end)
 630                 return TRACE_TYPE_UNHANDLED;
 631
 632         if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
 633                 /* Absolute time */
 634                 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
 635                         ret = print_graph_abs_time(iter->ts, s);
 636                         if (!ret)
 637                                 return TRACE_TYPE_PARTIAL_LINE;
 638                 }
 639
 640                 /* Cpu */
 641                 if (flags & TRACE_GRAPH_PRINT_CPU) {
 642                         ret = print_graph_cpu(s, cpu);
 643                         if (ret == TRACE_TYPE_PARTIAL_LINE)
 644                                 return TRACE_TYPE_PARTIAL_LINE;
 645                 }
 646
 647                 /* Proc */
 648                 if (flags & TRACE_GRAPH_PRINT_PROC) {
 649                         ret = print_graph_proc(s, pid);
 650                         if (ret == TRACE_TYPE_PARTIAL_LINE)
 651                                 return TRACE_TYPE_PARTIAL_LINE;
 652                         ret = trace_seq_printf(s, " | ");
 653                         if (!ret)
 654                                 return TRACE_TYPE_PARTIAL_LINE;
 655                 }
 656         }
 657
 658         /* No overhead */
 659         ret = print_graph_duration(DURATION_FILL_START, s, flags);
 660         if (ret != TRACE_TYPE_HANDLED)
 661                 return ret;
 662
 663         if (type == TRACE_GRAPH_ENT)
 664                 ret = trace_seq_printf(s, "==========>");
 665         else
 666                 ret = trace_seq_printf(s, "<==========");
 667
 668         if (!ret)
 669                 return TRACE_TYPE_PARTIAL_LINE;
 670
 671         ret = print_graph_duration(DURATION_FILL_END, s, flags);
 672         if (ret != TRACE_TYPE_HANDLED)
 673                 return ret;
 674
 675         ret = trace_seq_printf(s, "\n");
 676
 677         if (!ret)
 678                 return TRACE_TYPE_PARTIAL_LINE;
 679         return TRACE_TYPE_HANDLED;
 680 }
 681
 682 enum print_line_t
 683 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 684 {
 685         unsigned long nsecs_rem = do_div(duration, 1000);
 686         /* log10(ULONG_MAX) + '\0' */
 687         char msecs_str[21];
 688         char nsecs_str[5];
 689         int ret, len;
 690         int i;
 691
 692         sprintf(msecs_str, "%lu", (unsigned long) duration);
 693
 694         /* Print msecs */
 695         ret = trace_seq_printf(s, "%s", msecs_str);
 696         if (!ret)
 697                 return TRACE_TYPE_PARTIAL_LINE;
 698
 699         len = strlen(msecs_str);
 700
 701         /* Print nsecs (we don't want to exceed 7 numbers) */
 702         if (len < 7) {
 703                 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
 704
 705                 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
 706                 ret = trace_seq_printf(s, ".%s", nsecs_str);
 707                 if (!ret)
 708                         return TRACE_TYPE_PARTIAL_LINE;
 709                 len += strlen(nsecs_str);
 710         }
 711
 712         ret = trace_seq_printf(s, " us ");
 713         if (!ret)
 714                 return TRACE_TYPE_PARTIAL_LINE;
 715
 716         /* Print remaining spaces to fit the row's width */
 717         for (i = len; i < 7; i++) {
 718                 ret = trace_seq_printf(s, " ");
 719                 if (!ret)
 720                         return TRACE_TYPE_PARTIAL_LINE;
 721         }
 722         return TRACE_TYPE_HANDLED;
 723 }
 724
 725 static enum print_line_t
 726 print_graph_duration(unsigned long long duration, struct trace_seq *s,
 727                      u32 flags)
 728 {
 729         int ret = -1;
 730
 731         if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
 732             !(trace_flags & TRACE_ITER_CONTEXT_INFO))
 733                         return TRACE_TYPE_HANDLED;
 734
 735         /* No real adata, just filling the column with spaces */
 736         switch (duration) {
 737         case DURATION_FILL_FULL:
 738                 ret = trace_seq_printf(s, "              |  ");
 739                 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
 740         case DURATION_FILL_START:
 741                 ret = trace_seq_printf(s, "  ");
 742                 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
 743         case DURATION_FILL_END:
 744                 ret = trace_seq_printf(s, " |");
 745                 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
 746         }
 747
 748         /* Signal a overhead of time execution to the output */
 749         if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
 750                 /* Duration exceeded 100 msecs */
 751                 if (duration > 100000ULL)
 752                         ret = trace_seq_printf(s, "! ");
 753                 /* Duration exceeded 10 msecs */
 754                 else if (duration > 10000ULL)
 755                         ret = trace_seq_printf(s, "+ ");
 756         }
 757
 758         /*
 759          * The -1 means we either did not exceed the duration tresholds
 760          * or we dont want to print out the overhead. Either way we need
 761          * to fill out the space.
 762          */
 763         if (ret == -1)
 764                 ret = trace_seq_printf(s, "  ");
 765
 766         /* Catching here any failure happenned above */
 767         if (!ret)
 768                 return TRACE_TYPE_PARTIAL_LINE;
 769
 770         ret = trace_print_graph_duration(duration, s);
 771         if (ret != TRACE_TYPE_HANDLED)
 772                 return ret;
 773
 774         ret = trace_seq_printf(s, "|  ");
 775         if (!ret)
 776                 return TRACE_TYPE_PARTIAL_LINE;
 777
 778         return TRACE_TYPE_HANDLED;
 779 }
 780
 781 /* Case of a leaf function on its call entry */
 782 static enum print_line_t
 783 print_graph_entry_leaf(struct trace_iterator *iter,
 784                 struct ftrace_graph_ent_entry *entry,
 785                 struct ftrace_graph_ret_entry *ret_entry,
 786                 struct trace_seq *s, u32 flags)
 787 {
 788         struct fgraph_data *data = iter->private;
 789         struct ftrace_graph_ret *graph_ret;
 790         struct ftrace_graph_ent *call;
 791         unsigned long long duration;
 792         int ret;
 793         int i;
 794
 795         graph_ret = &ret_entry->ret;
 796         call = &entry->graph_ent;
 797         duration = graph_ret->rettime - graph_ret->calltime;
 798
 799         if (data) {
 800                 struct fgraph_cpu_data *cpu_data;
 801                 int cpu = iter->cpu;
 802
 803                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 804
 805                 /*
 806                  * Comments display at + 1 to depth. Since
 807                  * this is a leaf function, keep the comments
 808                  * equal to this depth.
 809                  */
 810                 cpu_data->depth = call->depth - 1;
 811
 812                 /* No need to keep this function around for this depth */
 813                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 814                         cpu_data->enter_funcs[call->depth] = 0;
 815         }
 816
 817         /* Overhead and duration */
 818         ret = print_graph_duration(duration, s, flags);
 819         if (ret == TRACE_TYPE_PARTIAL_LINE)
 820                 return TRACE_TYPE_PARTIAL_LINE;
 821
 822         /* Function */
 823         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 824                 ret = trace_seq_printf(s, " ");
 825                 if (!ret)
 826                         return TRACE_TYPE_PARTIAL_LINE;
 827         }
 828
 829         ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
 830         if (!ret)
 831                 return TRACE_TYPE_PARTIAL_LINE;
 832
 833         return TRACE_TYPE_HANDLED;
 834 }
 835
 836 static enum print_line_t
 837 print_graph_entry_nested(struct trace_iterator *iter,
 838                          struct ftrace_graph_ent_entry *entry,
 839                          struct trace_seq *s, int cpu, u32 flags)
 840 {
 841         struct ftrace_graph_ent *call = &entry->graph_ent;
 842         struct fgraph_data *data = iter->private;
 843         int ret;
 844         int i;
 845
 846         if (data) {
 847                 struct fgraph_cpu_data *cpu_data;
 848                 int cpu = iter->cpu;
 849
 850                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 851                 cpu_data->depth = call->depth;
 852
 853                 /* Save this function pointer to see if the exit matches */
 854                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 855                         cpu_data->enter_funcs[call->depth] = call->func;
 856         }
 857
 858         /* No time */
 859         ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
 860         if (ret != TRACE_TYPE_HANDLED)
 861                 return ret;
 862
 863         /* Function */
 864         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 865                 ret = trace_seq_printf(s, " ");
 866                 if (!ret)
 867                         return TRACE_TYPE_PARTIAL_LINE;
 868         }
 869
 870         ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
 871         if (!ret)
 872                 return TRACE_TYPE_PARTIAL_LINE;
 873
 874         /*
 875          * we already consumed the current entry to check the next one
 876          * and see if this is a leaf.
 877          */
 878         return TRACE_TYPE_NO_CONSUME;
 879 }
 880
 881 static enum print_line_t
 882 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 883                      int type, unsigned long addr, u32 flags)
 884 {
 885         struct fgraph_data *data = iter->private;
 886         struct trace_entry *ent = iter->ent;
 887         int cpu = iter->cpu;
 888         int ret;
 889
 890         /* Pid */
 891         if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
 892                 return TRACE_TYPE_PARTIAL_LINE;
 893
 894         if (type) {
 895                 /* Interrupt */
 896                 ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
 897                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 898                         return TRACE_TYPE_PARTIAL_LINE;
 899         }
 900
 901         if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
 902                 return 0;
 903
 904         /* Absolute time */
 905         if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
 906                 ret = print_graph_abs_time(iter->ts, s);
 907                 if (!ret)
 908                         return TRACE_TYPE_PARTIAL_LINE;
 909         }
 910
 911         /* Cpu */
 912         if (flags & TRACE_GRAPH_PRINT_CPU) {
 913                 ret = print_graph_cpu(s, cpu);
 914                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 915                         return TRACE_TYPE_PARTIAL_LINE;
 916         }
 917
 918         /* Proc */
 919         if (flags & TRACE_GRAPH_PRINT_PROC) {
 920                 ret = print_graph_proc(s, ent->pid);
 921                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 922                         return TRACE_TYPE_PARTIAL_LINE;
 923
 924                 ret = trace_seq_printf(s, " | ");
 925                 if (!ret)
 926                         return TRACE_TYPE_PARTIAL_LINE;
 927         }
 928
 929         /* Latency format */
 930         if (trace_flags & TRACE_ITER_LATENCY_FMT) {
 931                 ret = print_graph_lat_fmt(s, ent);
 932                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 933                         return TRACE_TYPE_PARTIAL_LINE;
 934         }
 935
 936         return 0;
 937 }
 938
 939 /*
 940  * Entry check for irq code
 941  *
 942  * returns 1 if
 943  *  - we are inside irq code
 944  *  - we just entered irq code
 945  *
 946  * retunns 0 if
 947  *  - funcgraph-interrupts option is set
 948  *  - we are not inside irq code
 949  */
 950 static int
 951 check_irq_entry(struct trace_iterator *iter, u32 flags,
 952                 unsigned long addr, int depth)
 953 {
 954         int cpu = iter->cpu;
 955         int *depth_irq;
 956         struct fgraph_data *data = iter->private;
 957
 958         /*
 959          * If we are either displaying irqs, or we got called as
 960          * a graph event and private data does not exist,
 961          * then we bypass the irq check.
 962          */
 963         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
 964             (!data))
 965                 return 0;
 966
 967         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 968
 969         /*
 970          * We are inside the irq code
 971          */
 972         if (*depth_irq >= 0)
 973                 return 1;
 974
 975         if ((addr < (unsigned long)__irqentry_text_start) ||
 976             (addr >= (unsigned long)__irqentry_text_end))
 977                 return 0;
 978
 979         /*
 980          * We are entering irq code.
 981          */
 982         *depth_irq = depth;
 983         return 1;
 984 }
 985
 986 /*
 987  * Return check for irq code
 988  *
 989  * returns 1 if
 990  *  - we are inside irq code
 991  *  - we just left irq code
 992  *
 993  * returns 0 if
 994  *  - funcgraph-interrupts option is set
 995  *  - we are not inside irq code
 996  */
 997 static int
 998 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
 999 {
1000         int cpu = iter->cpu;
1001         int *depth_irq;
1002         struct fgraph_data *data = iter->private;
1003
1004         /*
1005          * If we are either displaying irqs, or we got called as
1006          * a graph event and private data does not exist,
1007          * then we bypass the irq check.
1008          */
1009         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1010             (!data))
1011                 return 0;
1012
1013         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1014
1015         /*
1016          * We are not inside the irq code.
1017          */
1018         if (*depth_irq == -1)
1019                 return 0;
1020
1021         /*
1022          * We are inside the irq code, and this is returning entry.
1023          * Let's not trace it and clear the entry depth, since
1024          * we are out of irq code.
1025          *
1026          * This condition ensures that we 'leave the irq code' once
1027          * we are out of the entry depth. Thus protecting us from
1028          * the RETURN entry loss.
1029          */
1030         if (*depth_irq >= depth) {
1031                 *depth_irq = -1;
1032                 return 1;
1033         }
1034
1035         /*
1036          * We are inside the irq code, and this is not the entry.
1037          */
1038         return 1;
1039 }
1040
1041 static enum print_line_t
1042 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
1043                         struct trace_iterator *iter, u32 flags)
1044 {
1045         struct fgraph_data *data = iter->private;
1046         struct ftrace_graph_ent *call = &field->graph_ent;
1047         struct ftrace_graph_ret_entry *leaf_ret;
1048         static enum print_line_t ret;
1049         int cpu = iter->cpu;
1050
1051         if (check_irq_entry(iter, flags, call->func, call->depth))
1052                 return TRACE_TYPE_HANDLED;
1053
1054         if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
1055                 return TRACE_TYPE_PARTIAL_LINE;
1056
1057         leaf_ret = get_return_for_leaf(iter, field);
1058         if (leaf_ret)
1059                 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1060         else
1061                 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1062
1063         if (data) {
1064                 /*
1065                  * If we failed to write our output, then we need to make
1066                  * note of it. Because we already consumed our entry.
1067                  */
1068                 if (s->full) {
1069                         data->failed = 1;
1070                         data->cpu = cpu;
1071                 } else
1072                         data->failed = 0;
1073         }
1074
1075         return ret;
1076 }
1077
1078 static enum print_line_t
1079 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1080                    struct trace_entry *ent, struct trace_iterator *iter,
1081                    u32 flags)
1082 {
1083         unsigned long long duration = trace->rettime - trace->calltime;
1084         struct fgraph_data *data = iter->private;
1085         pid_t pid = ent->pid;
1086         int cpu = iter->cpu;
1087         int func_match = 1;
1088         int ret;
1089         int i;
1090
1091         if (check_irq_return(iter, flags, trace->depth))
1092                 return TRACE_TYPE_HANDLED;
1093
1094         if (data) {
1095                 struct fgraph_cpu_data *cpu_data;
1096                 int cpu = iter->cpu;
1097
1098                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1099
1100                 /*
1101                  * Comments display at + 1 to depth. This is the
1102                  * return from a function, we now want the comments
1103                  * to display at the same level of the bracket.
1104                  */
1105                 cpu_data->depth = trace->depth - 1;
1106
1107                 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
1108                         if (cpu_data->enter_funcs[trace->depth] != trace->func)
1109                                 func_match = 0;
1110                         cpu_data->enter_funcs[trace->depth] = 0;
1111                 }
1112         }
1113
1114         if (print_graph_prologue(iter, s, 0, 0, flags))
1115                 return TRACE_TYPE_PARTIAL_LINE;
1116
1117         /* Overhead and duration */
1118         ret = print_graph_duration(duration, s, flags);
1119         if (ret == TRACE_TYPE_PARTIAL_LINE)
1120                 return TRACE_TYPE_PARTIAL_LINE;
1121
1122         /* Closing brace */
1123         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
1124                 ret = trace_seq_printf(s, " ");
1125                 if (!ret)
1126                         return TRACE_TYPE_PARTIAL_LINE;
1127         }
1128
1129         /*
1130          * If the return function does not have a matching entry,
1131          * then the entry was lost. Instead of just printing
1132          * the '}' and letting the user guess what function this
1133          * belongs to, write out the function name.
1134          */
1135         if (func_match) {
1136                 ret = trace_seq_printf(s, "}\n");
1137                 if (!ret)
1138                         return TRACE_TYPE_PARTIAL_LINE;
1139         } else {
1140                 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1141                 if (!ret)
1142                         return TRACE_TYPE_PARTIAL_LINE;
1143         }
1144
1145         /* Overrun */
1146         if (flags & TRACE_GRAPH_PRINT_OVERRUN) {
1147                 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
1148                                         trace->overrun);
1149                 if (!ret)
1150                         return TRACE_TYPE_PARTIAL_LINE;
1151         }
1152
1153         ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1154                               cpu, pid, flags);
1155         if (ret == TRACE_TYPE_PARTIAL_LINE)
1156                 return TRACE_TYPE_PARTIAL_LINE;
1157
1158         return TRACE_TYPE_HANDLED;
1159 }
1160
1161 static enum print_line_t
1162 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1163                     struct trace_iterator *iter, u32 flags)
1164 {
1165         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1166         struct fgraph_data *data = iter->private;
1167         struct trace_event *event;
1168         int depth = 0;
1169         int ret;
1170         int i;
1171
1172         if (data)
1173                 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1174
1175         if (print_graph_prologue(iter, s, 0, 0, flags))
1176                 return TRACE_TYPE_PARTIAL_LINE;
1177
1178         /* No time */
1179         ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
1180         if (ret != TRACE_TYPE_HANDLED)
1181                 return ret;
1182
1183         /* Indentation */
1184         if (depth > 0)
1185                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
1186                         ret = trace_seq_printf(s, " ");
1187                         if (!ret)
1188                                 return TRACE_TYPE_PARTIAL_LINE;
1189                 }
1190
1191         /* The comment */
1192         ret = trace_seq_printf(s, "/* ");
1193         if (!ret)
1194                 return TRACE_TYPE_PARTIAL_LINE;
1195
1196         switch (iter->ent->type) {
1197         case TRACE_BPRINT:
1198                 ret = trace_print_bprintk_msg_only(iter);
1199                 if (ret != TRACE_TYPE_HANDLED)
1200                         return ret;
1201                 break;
1202         case TRACE_PRINT:
1203                 ret = trace_print_printk_msg_only(iter);
1204                 if (ret != TRACE_TYPE_HANDLED)
1205                         return ret;
1206                 break;
1207         default:
1208                 event = ftrace_find_event(ent->type);
1209                 if (!event)
1210                         return TRACE_TYPE_UNHANDLED;
1211
1212                 ret = event->funcs->trace(iter, sym_flags, event);
1213                 if (ret != TRACE_TYPE_HANDLED)
1214                         return ret;
1215         }
1216
1217         /* Strip ending newline */
1218         if (s->buffer[s->len - 1] == '\n') {
1219                 s->buffer[s->len - 1] = '\0';
1220                 s->len--;
1221         }
1222
1223         ret = trace_seq_printf(s, " */\n");
1224         if (!ret)
1225                 return TRACE_TYPE_PARTIAL_LINE;
1226
1227         return TRACE_TYPE_HANDLED;
1228 }
1229
1230
1231 enum print_line_t
1232 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1233 {
1234         struct ftrace_graph_ent_entry *field;
1235         struct fgraph_data *data = iter->private;
1236         struct trace_entry *entry = iter->ent;
1237         struct trace_seq *s = &iter->seq;
1238         int cpu = iter->cpu;
1239         int ret;
1240
1241         if (flags & TRACE_GRAPH_PRINT_FLAT)
1242                 return TRACE_TYPE_UNHANDLED;
1243
1244         if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1245                 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1246                 return TRACE_TYPE_HANDLED;
1247         }
1248
1249         /*
1250          * If the last output failed, there's a possibility we need
1251          * to print out the missing entry which would never go out.
1252          */
1253         if (data && data->failed) {
1254                 field = &data->ent;
1255                 iter->cpu = data->cpu;
1256                 ret = print_graph_entry(field, s, iter, flags);
1257                 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1258                         per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1259                         ret = TRACE_TYPE_NO_CONSUME;
1260                 }
1261                 iter->cpu = cpu;
1262                 return ret;
1263         }
1264
1265         switch (entry->type) {
1266         case TRACE_GRAPH_ENT: {
1267                 /*
1268                  * print_graph_entry() may consume the current event,
1269                  * thus @field may become invalid, so we need to save it.
1270                  * sizeof(struct ftrace_graph_ent_entry) is very small,
1271                  * it can be safely saved at the stack.
1272                  */
1273                 struct ftrace_graph_ent_entry saved;
1274                 trace_assign_type(field, entry);
1275                 saved = *field;
1276                 return print_graph_entry(&saved, s, iter, flags);
1277         }
1278         case TRACE_GRAPH_RET: {
1279                 struct ftrace_graph_ret_entry *field;
1280                 trace_assign_type(field, entry);
1281                 return print_graph_return(&field->ret, s, entry, iter, flags);
1282         }
1283         case TRACE_STACK:
1284         case TRACE_FN:
1285                 /* dont trace stack and functions as comments */
1286                 return TRACE_TYPE_UNHANDLED;
1287
1288         default:
1289                 return print_graph_comment(s, entry, iter, flags);
1290         }
1291
1292         return TRACE_TYPE_HANDLED;
1293 }
1294
1295 static enum print_line_t
1296 print_graph_function(struct trace_iterator *iter)
1297 {
1298         return print_graph_function_flags(iter, tracer_flags.val);
1299 }
1300
1301 static void print_lat_header(struct seq_file *s, u32 flags)
1302 {
1303         static const char spaces[] = "                " /* 16 spaces */
1304                 "    "                                  /* 4 spaces */
1305                 "                 ";                    /* 17 spaces */
1306         int size = 0;
1307
1308         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1309                 size += 16;
1310         if (flags & TRACE_GRAPH_PRINT_CPU)
1311                 size += 4;
1312         if (flags & TRACE_GRAPH_PRINT_PROC)
1313                 size += 17;
1314
1315         seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
1316         seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
1317         seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1318         seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
1319         seq_printf(s, "#%.*s||| /                      \n", size, spaces);
1320 }
1321
1322 static void __print_graph_headers_flags(struct seq_file *s, u32 flags)
1323 {
1324         int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1325
1326         if (lat)
1327                 print_lat_header(s, flags);
1328
1329         /* 1st line */
1330         seq_printf(s, "#");
1331         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1332                 seq_printf(s, "     TIME       ");
1333         if (flags & TRACE_GRAPH_PRINT_CPU)
1334                 seq_printf(s, " CPU");
1335         if (flags & TRACE_GRAPH_PRINT_PROC)
1336                 seq_printf(s, "  TASK/PID       ");
1337         if (lat)
1338                 seq_printf(s, "||||");
1339         if (flags & TRACE_GRAPH_PRINT_DURATION)
1340                 seq_printf(s, "  DURATION   ");
1341         seq_printf(s, "               FUNCTION CALLS\n");
1342
1343         /* 2nd line */
1344         seq_printf(s, "#");
1345         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1346                 seq_printf(s, "      |         ");
1347         if (flags & TRACE_GRAPH_PRINT_CPU)
1348                 seq_printf(s, " |  ");
1349         if (flags & TRACE_GRAPH_PRINT_PROC)
1350                 seq_printf(s, "   |    |        ");
1351         if (lat)
1352                 seq_printf(s, "||||");
1353         if (flags & TRACE_GRAPH_PRINT_DURATION)
1354                 seq_printf(s, "   |   |      ");
1355         seq_printf(s, "               |   |   |   |\n");
1356 }
1357
1358 void print_graph_headers(struct seq_file *s)
1359 {
1360         print_graph_headers_flags(s, tracer_flags.val);
1361 }
1362
1363 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1364 {
1365         struct trace_iterator *iter = s->private;
1366
1367         if (flags & TRACE_GRAPH_PRINT_FLAT) {
1368                 trace_default_header(s);
1369                 return;
1370         }
1371
1372         if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
1373                 return;
1374
1375         if (trace_flags & TRACE_ITER_LATENCY_FMT) {
1376                 /* print nothing if the buffers are empty */
1377                 if (trace_empty(iter))
1378                         return;
1379
1380                 print_trace_header(s, iter);
1381         }
1382
1383         __print_graph_headers_flags(s, flags);
1384 }
1385
1386 void graph_trace_open(struct trace_iterator *iter)
1387 {
1388         /* pid and depth on the last trace processed */
1389         struct fgraph_data *data;
1390         int cpu;
1391
1392         iter->private = NULL;
1393
1394         data = kzalloc(sizeof(*data), GFP_KERNEL);
1395         if (!data)
1396                 goto out_err;
1397
1398         data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
1399         if (!data->cpu_data)
1400                 goto out_err_free;
1401
1402         for_each_possible_cpu(cpu) {
1403                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1404                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1405                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1406                 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1407
1408                 *pid = -1;
1409                 *depth = 0;
1410                 *ignore = 0;
1411                 *depth_irq = -1;
1412         }
1413
1414         iter->private = data;
1415
1416         return;
1417
1418  out_err_free:
1419         kfree(data);
1420  out_err:
1421         pr_warning("function graph tracer: not enough memory\n");
1422 }
1423
1424 void graph_trace_close(struct trace_iterator *iter)
1425 {
1426         struct fgraph_data *data = iter->private;
1427
1428         if (data) {
1429                 free_percpu(data->cpu_data);
1430                 kfree(data);
1431         }
1432 }
1433
1434 static int func_graph_set_flag(u32 old_flags, u32 bit, int set)
1435 {
1436         if (bit == TRACE_GRAPH_PRINT_IRQS)
1437                 ftrace_graph_skip_irqs = !set;
1438
1439         return 0;
1440 }
1441
1442 static struct tracer graph_trace __read_mostly = {
1443         .name           = "function_graph",
1444         .open           = graph_trace_open,
1445         .pipe_open      = graph_trace_open,
1446         .close          = graph_trace_close,
1447         .pipe_close     = graph_trace_close,
1448         .wait_pipe      = poll_wait_pipe,
1449         .init           = graph_trace_init,
1450         .reset          = graph_trace_reset,
1451         .print_line     = print_graph_function,
1452         .print_header   = print_graph_headers,
1453         .flags          = &tracer_flags,
1454         .set_flag       = func_graph_set_flag,
1455 #ifdef CONFIG_FTRACE_SELFTEST
1456         .selftest       = trace_selftest_startup_function_graph,
1457 #endif
1458 };
1459
1460
1461 static ssize_t
1462 graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1463                   loff_t *ppos)
1464 {
1465         unsigned long val;
1466         int ret;
1467
1468         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1469         if (ret)
1470                 return ret;
1471
1472         max_depth = val;
1473
1474         *ppos += cnt;
1475
1476         return cnt;
1477 }
1478
1479 static ssize_t
1480 graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1481                  loff_t *ppos)
1482 {
1483         char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1484         int n;
1485
1486         n = sprintf(buf, "%d\n", max_depth);
1487
1488         return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1489 }
1490
1491 static const struct file_operations graph_depth_fops = {
1492         .open           = tracing_open_generic,
1493         .write          = graph_depth_write,
1494         .read           = graph_depth_read,
1495         .llseek         = generic_file_llseek,
1496 };
1497
1498 static __init int init_graph_debugfs(void)
1499 {
1500         struct dentry *d_tracer;
1501
1502         d_tracer = tracing_init_dentry();
1503         if (!d_tracer)
1504                 return 0;
1505
1506         trace_create_file("max_graph_depth", 0644, d_tracer,
1507                           NULL, &graph_depth_fops);
1508
1509         return 0;
1510 }
1511 fs_initcall(init_graph_debugfs);
1512
1513 static __init int init_graph_trace(void)
1514 {
1515         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1516
1517         return register_tracer(&graph_trace);
1518 }
1519
1520 core_initcall(init_graph_trace);