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
  50 static unsigned int max_depth;
  51
  52 static struct tracer_opt trace_opts[] = {
  53         /* Display overruns? (for self-debug purpose) */
  54         { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
  55         /* Display CPU ? */
  56         { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
  57         /* Display Overhead ? */
  58         { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
  59         /* Display proc name/pid */
  60         { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
  61         /* Display duration of execution */
  62         { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
  63         /* Display absolute time of an entry */
  64         { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
  65         /* Display interrupts */
  66         { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
  67         { } /* Empty entry */
  68 };
  69
  70 static struct tracer_flags tracer_flags = {
  71         /* Don't display overruns and proc by default */
  72         .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
  73                TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS,
  74         .opts = trace_opts
  75 };
  76
  77 static struct trace_array *graph_array;
  78
  79 /*
  80  * DURATION column is being also used to display IRQ signs,
  81  * following values are used by print_graph_irq and others
  82  * to fill in space into DURATION column.
  83  */
  84 enum {
  85         FLAGS_FILL_FULL  = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
  86         FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
  87         FLAGS_FILL_END   = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
  88 };
  89
  90 static enum print_line_t
  91 print_graph_duration(unsigned long long duration, struct trace_seq *s,
  92                      u32 flags);
  93
  94 /* Add a function return address to the trace stack on thread info.*/
  95 int
  96 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
  97                          unsigned long frame_pointer)
  98 {
  99         unsigned long long calltime;
 100         int index;
 101
 102         if (!current->ret_stack)
 103                 return -EBUSY;
 104
 105         /*
 106          * We must make sure the ret_stack is tested before we read
 107          * anything else.
 108          */
 109         smp_rmb();
 110
 111         /* The return trace stack is full */
 112         if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
 113                 atomic_inc(&current->trace_overrun);
 114                 return -EBUSY;
 115         }
 116
 117         /*
 118          * The curr_ret_stack is an index to ftrace return stack of
 119          * current task.  Its value should be in [0, FTRACE_RETFUNC_
 120          * DEPTH) when the function graph tracer is used.  To support
 121          * filtering out specific functions, it makes the index
 122          * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
 123          * so when it sees a negative index the ftrace will ignore
 124          * the record.  And the index gets recovered when returning
 125          * from the filtered function by adding the FTRACE_NOTRACE_
 126          * DEPTH and then it'll continue to record functions normally.
 127          *
 128          * The curr_ret_stack is initialized to -1 and get increased
 129          * in this function.  So it can be less than -1 only if it was
 130          * filtered out via ftrace_graph_notrace_addr() which can be
 131          * set from set_graph_notrace file in debugfs by user.
 132          */
 133         if (current->curr_ret_stack < -1)
 134                 return -EBUSY;
 135
 136         calltime = trace_clock_local();
 137
 138         index = ++current->curr_ret_stack;
 139         if (ftrace_graph_notrace_addr(func))
 140                 current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
 141         barrier();
 142         current->ret_stack[index].ret = ret;
 143         current->ret_stack[index].func = func;
 144         current->ret_stack[index].calltime = calltime;
 145         current->ret_stack[index].subtime = 0;
 146         current->ret_stack[index].fp = frame_pointer;
 147         *depth = current->curr_ret_stack;
 148
 149         return 0;
 150 }
 151
 152 /* Retrieve a function return address to the trace stack on thread info.*/
 153 static void
 154 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
 155                         unsigned long frame_pointer)
 156 {
 157         int index;
 158
 159         index = current->curr_ret_stack;
 160
 161         /*
 162          * A negative index here means that it's just returned from a
 163          * notrace'd function.  Recover index to get an original
 164          * return address.  See ftrace_push_return_trace().
 165          *
 166          * TODO: Need to check whether the stack gets corrupted.
 167          */
 168         if (index < 0)
 169                 index += FTRACE_NOTRACE_DEPTH;
 170
 171         if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
 172                 ftrace_graph_stop();
 173                 WARN_ON(1);
 174                 /* Might as well panic, otherwise we have no where to go */
 175                 *ret = (unsigned long)panic;
 176                 return;
 177         }
 178
 179 #if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY)
 180         /*
 181          * The arch may choose to record the frame pointer used
 182          * and check it here to make sure that it is what we expect it
 183          * to be. If gcc does not set the place holder of the return
 184          * address in the frame pointer, and does a copy instead, then
 185          * the function graph trace will fail. This test detects this
 186          * case.
 187          *
 188          * Currently, x86_32 with optimize for size (-Os) makes the latest
 189          * gcc do the above.
 190          *
 191          * Note, -mfentry does not use frame pointers, and this test
 192          *  is not needed if CC_USING_FENTRY is set.
 193          */
 194         if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
 195                 ftrace_graph_stop();
 196                 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
 197                      "  from func %ps return to %lx\n",
 198                      current->ret_stack[index].fp,
 199                      frame_pointer,
 200                      (void *)current->ret_stack[index].func,
 201                      current->ret_stack[index].ret);
 202                 *ret = (unsigned long)panic;
 203                 return;
 204         }
 205 #endif
 206
 207         *ret = current->ret_stack[index].ret;
 208         trace->func = current->ret_stack[index].func;
 209         trace->calltime = current->ret_stack[index].calltime;
 210         trace->overrun = atomic_read(&current->trace_overrun);
 211         trace->depth = index;
 212 }
 213
 214 /*
 215  * Send the trace to the ring-buffer.
 216  * @return the original return address.
 217  */
 218 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 219 {
 220         struct ftrace_graph_ret trace;
 221         unsigned long ret;
 222
 223         ftrace_pop_return_trace(&trace, &ret, frame_pointer);
 224         trace.rettime = trace_clock_local();
 225         barrier();
 226         current->curr_ret_stack--;
 227         /*
 228          * The curr_ret_stack can be less than -1 only if it was
 229          * filtered out and it's about to return from the function.
 230          * Recover the index and continue to trace normal functions.
 231          */
 232         if (current->curr_ret_stack < -1) {
 233                 current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
 234                 return ret;
 235         }
 236
 237         /*
 238          * The trace should run after decrementing the ret counter
 239          * in case an interrupt were to come in. We don't want to
 240          * lose the interrupt if max_depth is set.
 241          */
 242         ftrace_graph_return(&trace);
 243
 244         if (unlikely(!ret)) {
 245                 ftrace_graph_stop();
 246                 WARN_ON(1);
 247                 /* Might as well panic. What else to do? */
 248                 ret = (unsigned long)panic;
 249         }
 250
 251         return ret;
 252 }
 253
 254 int __trace_graph_entry(struct trace_array *tr,
 255                                 struct ftrace_graph_ent *trace,
 256                                 unsigned long flags,
 257                                 int pc)
 258 {
 259         struct ftrace_event_call *call = &event_funcgraph_entry;
 260         struct ring_buffer_event *event;
 261         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 262         struct ftrace_graph_ent_entry *entry;
 263
 264         if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
 265                 return 0;
 266
 267         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
 268                                           sizeof(*entry), flags, pc);
 269         if (!event)
 270                 return 0;
 271         entry   = ring_buffer_event_data(event);
 272         entry->graph_ent                        = *trace;
 273         if (!call_filter_check_discard(call, entry, buffer, event))
 274                 __buffer_unlock_commit(buffer, event);
 275
 276         return 1;
 277 }
 278
 279 static inline int ftrace_graph_ignore_irqs(void)
 280 {
 281         if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
 282                 return 0;
 283
 284         return in_irq();
 285 }
 286
 287 int trace_graph_entry(struct ftrace_graph_ent *trace)
 288 {
 289         struct trace_array *tr = graph_array;
 290         struct trace_array_cpu *data;
 291         unsigned long flags;
 292         long disabled;
 293         int ret;
 294         int cpu;
 295         int pc;
 296
 297         if (!ftrace_trace_task(current))
 298                 return 0;
 299
 300         /* trace it when it is-nested-in or is a function enabled. */
 301         if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
 302              ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
 303             (max_depth && trace->depth >= max_depth))
 304                 return 0;
 305
 306         /*
 307          * Do not trace a function if it's filtered by set_graph_notrace.
 308          * Make the index of ret stack negative to indicate that it should
 309          * ignore further functions.  But it needs its own ret stack entry
 310          * to recover the original index in order to continue tracing after
 311          * returning from the function.
 312          */
 313         if (ftrace_graph_notrace_addr(trace->func))
 314                 return 1;
 315
 316         local_irq_save(flags);
 317         cpu = raw_smp_processor_id();
 318         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 319         disabled = atomic_inc_return(&data->disabled);
 320         if (likely(disabled == 1)) {
 321                 pc = preempt_count();
 322                 ret = __trace_graph_entry(tr, trace, flags, pc);
 323         } else {
 324                 ret = 0;
 325         }
 326
 327         atomic_dec(&data->disabled);
 328         local_irq_restore(flags);
 329
 330         return ret;
 331 }
 332
 333 int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
 334 {
 335         if (tracing_thresh)
 336                 return 1;
 337         else
 338                 return trace_graph_entry(trace);
 339 }
 340
 341 static void
 342 __trace_graph_function(struct trace_array *tr,
 343                 unsigned long ip, unsigned long flags, int pc)
 344 {
 345         u64 time = trace_clock_local();
 346         struct ftrace_graph_ent ent = {
 347                 .func  = ip,
 348                 .depth = 0,
 349         };
 350         struct ftrace_graph_ret ret = {
 351                 .func     = ip,
 352                 .depth    = 0,
 353                 .calltime = time,
 354                 .rettime  = time,
 355         };
 356
 357         __trace_graph_entry(tr, &ent, flags, pc);
 358         __trace_graph_return(tr, &ret, flags, pc);
 359 }
 360
 361 void
 362 trace_graph_function(struct trace_array *tr,
 363                 unsigned long ip, unsigned long parent_ip,
 364                 unsigned long flags, int pc)
 365 {
 366         __trace_graph_function(tr, ip, flags, pc);
 367 }
 368
 369 void __trace_graph_return(struct trace_array *tr,
 370                                 struct ftrace_graph_ret *trace,
 371                                 unsigned long flags,
 372                                 int pc)
 373 {
 374         struct ftrace_event_call *call = &event_funcgraph_exit;
 375         struct ring_buffer_event *event;
 376         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 377         struct ftrace_graph_ret_entry *entry;
 378
 379         if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
 380                 return;
 381
 382         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
 383                                           sizeof(*entry), flags, pc);
 384         if (!event)
 385                 return;
 386         entry   = ring_buffer_event_data(event);
 387         entry->ret                              = *trace;
 388         if (!call_filter_check_discard(call, entry, buffer, event))
 389                 __buffer_unlock_commit(buffer, event);
 390 }
 391
 392 void trace_graph_return(struct ftrace_graph_ret *trace)
 393 {
 394         struct trace_array *tr = graph_array;
 395         struct trace_array_cpu *data;
 396         unsigned long flags;
 397         long disabled;
 398         int cpu;
 399         int pc;
 400
 401         local_irq_save(flags);
 402         cpu = raw_smp_processor_id();
 403         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 404         disabled = atomic_inc_return(&data->disabled);
 405         if (likely(disabled == 1)) {
 406                 pc = preempt_count();
 407                 __trace_graph_return(tr, trace, flags, pc);
 408         }
 409         atomic_dec(&data->disabled);
 410         local_irq_restore(flags);
 411 }
 412
 413 void set_graph_array(struct trace_array *tr)
 414 {
 415         graph_array = tr;
 416
 417         /* Make graph_array visible before we start tracing */
 418
 419         smp_mb();
 420 }
 421
 422 void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 423 {
 424         if (tracing_thresh &&
 425             (trace->rettime - trace->calltime < tracing_thresh))
 426                 return;
 427         else
 428                 trace_graph_return(trace);
 429 }
 430
 431 static int graph_trace_init(struct trace_array *tr)
 432 {
 433         int ret;
 434
 435         set_graph_array(tr);
 436         if (tracing_thresh)
 437                 ret = register_ftrace_graph(&trace_graph_thresh_return,
 438                                             &trace_graph_thresh_entry);
 439         else
 440                 ret = register_ftrace_graph(&trace_graph_return,
 441                                             &trace_graph_entry);
 442         if (ret)
 443                 return ret;
 444         tracing_start_cmdline_record();
 445
 446         return 0;
 447 }
 448
 449 static void graph_trace_reset(struct trace_array *tr)
 450 {
 451         tracing_stop_cmdline_record();
 452         unregister_ftrace_graph();
 453 }
 454
 455 static int max_bytes_for_cpu;
 456
 457 static enum print_line_t
 458 print_graph_cpu(struct trace_seq *s, int cpu)
 459 {
 460         int ret;
 461
 462         /*
 463          * Start with a space character - to make it stand out
 464          * to the right a bit when trace output is pasted into
 465          * email:
 466          */
 467         ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 468         if (!ret)
 469                 return TRACE_TYPE_PARTIAL_LINE;
 470
 471         return TRACE_TYPE_HANDLED;
 472 }
 473
 474 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 475
 476 static enum print_line_t
 477 print_graph_proc(struct trace_seq *s, pid_t pid)
 478 {
 479         char comm[TASK_COMM_LEN];
 480         /* sign + log10(MAX_INT) + '\0' */
 481         char pid_str[11];
 482         int spaces = 0;
 483         int ret;
 484         int len;
 485         int i;
 486
 487         trace_find_cmdline(pid, comm);
 488         comm[7] = '\0';
 489         sprintf(pid_str, "%d", pid);
 490
 491         /* 1 stands for the "-" character */
 492         len = strlen(comm) + strlen(pid_str) + 1;
 493
 494         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 495                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 496
 497         /* First spaces to align center */
 498         for (i = 0; i < spaces / 2; i++) {
 499                 ret = trace_seq_putc(s, ' ');
 500                 if (!ret)
 501                         return TRACE_TYPE_PARTIAL_LINE;
 502         }
 503
 504         ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
 505         if (!ret)
 506                 return TRACE_TYPE_PARTIAL_LINE;
 507
 508         /* Last spaces to align center */
 509         for (i = 0; i < spaces - (spaces / 2); i++) {
 510                 ret = trace_seq_putc(s, ' ');
 511                 if (!ret)
 512                         return TRACE_TYPE_PARTIAL_LINE;
 513         }
 514         return TRACE_TYPE_HANDLED;
 515 }
 516
 517
 518 static enum print_line_t
 519 print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 520 {
 521         if (!trace_seq_putc(s, ' '))
 522                 return 0;
 523
 524         return trace_print_lat_fmt(s, entry);
 525 }
 526
 527 /* If the pid changed since the last trace, output this event */
 528 static enum print_line_t
 529 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 530 {
 531         pid_t prev_pid;
 532         pid_t *last_pid;
 533         int ret;
 534
 535         if (!data)
 536                 return TRACE_TYPE_HANDLED;
 537
 538         last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
 539
 540         if (*last_pid == pid)
 541                 return TRACE_TYPE_HANDLED;
 542
 543         prev_pid = *last_pid;
 544         *last_pid = pid;
 545
 546         if (prev_pid == -1)
 547                 return TRACE_TYPE_HANDLED;
 548 /*
 549  * Context-switch trace line:
 550
 551  ------------------------------------------
 552  | 1)  migration/0--1  =>  sshd-1755
 553  ------------------------------------------
 554
 555  */
 556         ret = trace_seq_puts(s,
 557                 " ------------------------------------------\n");
 558         if (!ret)
 559                 return TRACE_TYPE_PARTIAL_LINE;
 560
 561         ret = print_graph_cpu(s, cpu);
 562         if (ret == TRACE_TYPE_PARTIAL_LINE)
 563                 return TRACE_TYPE_PARTIAL_LINE;
 564
 565         ret = print_graph_proc(s, prev_pid);
 566         if (ret == TRACE_TYPE_PARTIAL_LINE)
 567                 return TRACE_TYPE_PARTIAL_LINE;
 568
 569         ret = trace_seq_puts(s, " => ");
 570         if (!ret)
 571                 return TRACE_TYPE_PARTIAL_LINE;
 572
 573         ret = print_graph_proc(s, pid);
 574         if (ret == TRACE_TYPE_PARTIAL_LINE)
 575                 return TRACE_TYPE_PARTIAL_LINE;
 576
 577         ret = trace_seq_puts(s,
 578                 "\n ------------------------------------------\n\n");
 579         if (!ret)
 580                 return TRACE_TYPE_PARTIAL_LINE;
 581
 582         return TRACE_TYPE_HANDLED;
 583 }
 584
 585 static struct ftrace_graph_ret_entry *
 586 get_return_for_leaf(struct trace_iterator *iter,
 587                 struct ftrace_graph_ent_entry *curr)
 588 {
 589         struct fgraph_data *data = iter->private;
 590         struct ring_buffer_iter *ring_iter = NULL;
 591         struct ring_buffer_event *event;
 592         struct ftrace_graph_ret_entry *next;
 593
 594         /*
 595          * If the previous output failed to write to the seq buffer,
 596          * then we just reuse the data from before.
 597          */
 598         if (data && data->failed) {
 599                 curr = &data->ent;
 600                 next = &data->ret;
 601         } else {
 602
 603                 ring_iter = trace_buffer_iter(iter, iter->cpu);
 604
 605                 /* First peek to compare current entry and the next one */
 606                 if (ring_iter)
 607                         event = ring_buffer_iter_peek(ring_iter, NULL);
 608                 else {
 609                         /*
 610                          * We need to consume the current entry to see
 611                          * the next one.
 612                          */
 613                         ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
 614                                             NULL, NULL);
 615                         event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
 616                                                  NULL, NULL);
 617                 }
 618
 619                 if (!event)
 620                         return NULL;
 621
 622                 next = ring_buffer_event_data(event);
 623
 624                 if (data) {
 625                         /*
 626                          * Save current and next entries for later reference
 627                          * if the output fails.
 628                          */
 629                         data->ent = *curr;
 630                         /*
 631                          * If the next event is not a return type, then
 632                          * we only care about what type it is. Otherwise we can
 633                          * safely copy the entire event.
 634                          */
 635                         if (next->ent.type == TRACE_GRAPH_RET)
 636                                 data->ret = *next;
 637                         else
 638                                 data->ret.ent.type = next->ent.type;
 639                 }
 640         }
 641
 642         if (next->ent.type != TRACE_GRAPH_RET)
 643                 return NULL;
 644
 645         if (curr->ent.pid != next->ent.pid ||
 646                         curr->graph_ent.func != next->ret.func)
 647                 return NULL;
 648
 649         /* this is a leaf, now advance the iterator */
 650         if (ring_iter)
 651                 ring_buffer_read(ring_iter, NULL);
 652
 653         return next;
 654 }
 655
 656 static int print_graph_abs_time(u64 t, struct trace_seq *s)
 657 {
 658         unsigned long usecs_rem;
 659
 660         usecs_rem = do_div(t, NSEC_PER_SEC);
 661         usecs_rem /= 1000;
 662
 663         return trace_seq_printf(s, "%5lu.%06lu |  ",
 664                         (unsigned long)t, usecs_rem);
 665 }
 666
 667 static enum print_line_t
 668 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 669                 enum trace_type type, int cpu, pid_t pid, u32 flags)
 670 {
 671         int ret;
 672         struct trace_seq *s = &iter->seq;
 673
 674         if (addr < (unsigned long)__irqentry_text_start ||
 675                 addr >= (unsigned long)__irqentry_text_end)
 676                 return TRACE_TYPE_UNHANDLED;
 677
 678         if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
 679                 /* Absolute time */
 680                 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
 681                         ret = print_graph_abs_time(iter->ts, s);
 682                         if (!ret)
 683                                 return TRACE_TYPE_PARTIAL_LINE;
 684                 }
 685
 686                 /* Cpu */
 687                 if (flags & TRACE_GRAPH_PRINT_CPU) {
 688                         ret = print_graph_cpu(s, cpu);
 689                         if (ret == TRACE_TYPE_PARTIAL_LINE)
 690                                 return TRACE_TYPE_PARTIAL_LINE;
 691                 }
 692
 693                 /* Proc */
 694                 if (flags & TRACE_GRAPH_PRINT_PROC) {
 695                         ret = print_graph_proc(s, pid);
 696                         if (ret == TRACE_TYPE_PARTIAL_LINE)
 697                                 return TRACE_TYPE_PARTIAL_LINE;
 698                         ret = trace_seq_puts(s, " | ");
 699                         if (!ret)
 700                                 return TRACE_TYPE_PARTIAL_LINE;
 701                 }
 702         }
 703
 704         /* No overhead */
 705         ret = print_graph_duration(0, s, flags | FLAGS_FILL_START);
 706         if (ret != TRACE_TYPE_HANDLED)
 707                 return ret;
 708
 709         if (type == TRACE_GRAPH_ENT)
 710                 ret = trace_seq_puts(s, "==========>");
 711         else
 712                 ret = trace_seq_puts(s, "<==========");
 713
 714         if (!ret)
 715                 return TRACE_TYPE_PARTIAL_LINE;
 716
 717         ret = print_graph_duration(0, s, flags | FLAGS_FILL_END);
 718         if (ret != TRACE_TYPE_HANDLED)
 719                 return ret;
 720
 721         ret = trace_seq_putc(s, '\n');
 722
 723         if (!ret)
 724                 return TRACE_TYPE_PARTIAL_LINE;
 725         return TRACE_TYPE_HANDLED;
 726 }
 727
 728 enum print_line_t
 729 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 730 {
 731         unsigned long nsecs_rem = do_div(duration, 1000);
 732         /* log10(ULONG_MAX) + '\0' */
 733         char msecs_str[21];
 734         char nsecs_str[5];
 735         int ret, len;
 736         int i;
 737
 738         sprintf(msecs_str, "%lu", (unsigned long) duration);
 739
 740         /* Print msecs */
 741         ret = trace_seq_printf(s, "%s", msecs_str);
 742         if (!ret)
 743                 return TRACE_TYPE_PARTIAL_LINE;
 744
 745         len = strlen(msecs_str);
 746
 747         /* Print nsecs (we don't want to exceed 7 numbers) */
 748         if (len < 7) {
 749                 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
 750
 751                 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
 752                 ret = trace_seq_printf(s, ".%s", nsecs_str);
 753                 if (!ret)
 754                         return TRACE_TYPE_PARTIAL_LINE;
 755                 len += strlen(nsecs_str);
 756         }
 757
 758         ret = trace_seq_puts(s, " us ");
 759         if (!ret)
 760                 return TRACE_TYPE_PARTIAL_LINE;
 761
 762         /* Print remaining spaces to fit the row's width */
 763         for (i = len; i < 7; i++) {
 764                 ret = trace_seq_putc(s, ' ');
 765                 if (!ret)
 766                         return TRACE_TYPE_PARTIAL_LINE;
 767         }
 768         return TRACE_TYPE_HANDLED;
 769 }
 770
 771 static enum print_line_t
 772 print_graph_duration(unsigned long long duration, struct trace_seq *s,
 773                      u32 flags)
 774 {
 775         int ret = -1;
 776
 777         if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
 778             !(trace_flags & TRACE_ITER_CONTEXT_INFO))
 779                         return TRACE_TYPE_HANDLED;
 780
 781         /* No real adata, just filling the column with spaces */
 782         switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
 783         case FLAGS_FILL_FULL:
 784                 ret = trace_seq_puts(s, "              |  ");
 785                 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
 786         case FLAGS_FILL_START:
 787                 ret = trace_seq_puts(s, "  ");
 788                 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
 789         case FLAGS_FILL_END:
 790                 ret = trace_seq_puts(s, " |");
 791                 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
 792         }
 793
 794         /* Signal a overhead of time execution to the output */
 795         if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
 796                 /* Duration exceeded 100 msecs */
 797                 if (duration > 100000ULL)
 798                         ret = trace_seq_puts(s, "! ");
 799                 /* Duration exceeded 10 msecs */
 800                 else if (duration > 10000ULL)
 801                         ret = trace_seq_puts(s, "+ ");
 802         }
 803
 804         /*
 805          * The -1 means we either did not exceed the duration tresholds
 806          * or we dont want to print out the overhead. Either way we need
 807          * to fill out the space.
 808          */
 809         if (ret == -1)
 810                 ret = trace_seq_puts(s, "  ");
 811
 812         /* Catching here any failure happenned above */
 813         if (!ret)
 814                 return TRACE_TYPE_PARTIAL_LINE;
 815
 816         ret = trace_print_graph_duration(duration, s);
 817         if (ret != TRACE_TYPE_HANDLED)
 818                 return ret;
 819
 820         ret = trace_seq_puts(s, "|  ");
 821         if (!ret)
 822                 return TRACE_TYPE_PARTIAL_LINE;
 823
 824         return TRACE_TYPE_HANDLED;
 825 }
 826
 827 /* Case of a leaf function on its call entry */
 828 static enum print_line_t
 829 print_graph_entry_leaf(struct trace_iterator *iter,
 830                 struct ftrace_graph_ent_entry *entry,
 831                 struct ftrace_graph_ret_entry *ret_entry,
 832                 struct trace_seq *s, u32 flags)
 833 {
 834         struct fgraph_data *data = iter->private;
 835         struct ftrace_graph_ret *graph_ret;
 836         struct ftrace_graph_ent *call;
 837         unsigned long long duration;
 838         int ret;
 839         int i;
 840
 841         graph_ret = &ret_entry->ret;
 842         call = &entry->graph_ent;
 843         duration = graph_ret->rettime - graph_ret->calltime;
 844
 845         if (data) {
 846                 struct fgraph_cpu_data *cpu_data;
 847                 int cpu = iter->cpu;
 848
 849                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 850
 851                 /*
 852                  * Comments display at + 1 to depth. Since
 853                  * this is a leaf function, keep the comments
 854                  * equal to this depth.
 855                  */
 856                 cpu_data->depth = call->depth - 1;
 857
 858                 /* No need to keep this function around for this depth */
 859                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 860                         cpu_data->enter_funcs[call->depth] = 0;
 861         }
 862
 863         /* Overhead and duration */
 864         ret = print_graph_duration(duration, s, flags);
 865         if (ret == TRACE_TYPE_PARTIAL_LINE)
 866                 return TRACE_TYPE_PARTIAL_LINE;
 867
 868         /* Function */
 869         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 870                 ret = trace_seq_putc(s, ' ');
 871                 if (!ret)
 872                         return TRACE_TYPE_PARTIAL_LINE;
 873         }
 874
 875         ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
 876         if (!ret)
 877                 return TRACE_TYPE_PARTIAL_LINE;
 878
 879         return TRACE_TYPE_HANDLED;
 880 }
 881
 882 static enum print_line_t
 883 print_graph_entry_nested(struct trace_iterator *iter,
 884                          struct ftrace_graph_ent_entry *entry,
 885                          struct trace_seq *s, int cpu, u32 flags)
 886 {
 887         struct ftrace_graph_ent *call = &entry->graph_ent;
 888         struct fgraph_data *data = iter->private;
 889         int ret;
 890         int i;
 891
 892         if (data) {
 893                 struct fgraph_cpu_data *cpu_data;
 894                 int cpu = iter->cpu;
 895
 896                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 897                 cpu_data->depth = call->depth;
 898
 899                 /* Save this function pointer to see if the exit matches */
 900                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 901                         cpu_data->enter_funcs[call->depth] = call->func;
 902         }
 903
 904         /* No time */
 905         ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
 906         if (ret != TRACE_TYPE_HANDLED)
 907                 return ret;
 908
 909         /* Function */
 910         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 911                 ret = trace_seq_putc(s, ' ');
 912                 if (!ret)
 913                         return TRACE_TYPE_PARTIAL_LINE;
 914         }
 915
 916         ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
 917         if (!ret)
 918                 return TRACE_TYPE_PARTIAL_LINE;
 919
 920         /*
 921          * we already consumed the current entry to check the next one
 922          * and see if this is a leaf.
 923          */
 924         return TRACE_TYPE_NO_CONSUME;
 925 }
 926
 927 static enum print_line_t
 928 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 929                      int type, unsigned long addr, u32 flags)
 930 {
 931         struct fgraph_data *data = iter->private;
 932         struct trace_entry *ent = iter->ent;
 933         int cpu = iter->cpu;
 934         int ret;
 935
 936         /* Pid */
 937         if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
 938                 return TRACE_TYPE_PARTIAL_LINE;
 939
 940         if (type) {
 941                 /* Interrupt */
 942                 ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
 943                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 944                         return TRACE_TYPE_PARTIAL_LINE;
 945         }
 946
 947         if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
 948                 return 0;
 949
 950         /* Absolute time */
 951         if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
 952                 ret = print_graph_abs_time(iter->ts, s);
 953                 if (!ret)
 954                         return TRACE_TYPE_PARTIAL_LINE;
 955         }
 956
 957         /* Cpu */
 958         if (flags & TRACE_GRAPH_PRINT_CPU) {
 959                 ret = print_graph_cpu(s, cpu);
 960                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 961                         return TRACE_TYPE_PARTIAL_LINE;
 962         }
 963
 964         /* Proc */
 965         if (flags & TRACE_GRAPH_PRINT_PROC) {
 966                 ret = print_graph_proc(s, ent->pid);
 967                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 968                         return TRACE_TYPE_PARTIAL_LINE;
 969
 970                 ret = trace_seq_puts(s, " | ");
 971                 if (!ret)
 972                         return TRACE_TYPE_PARTIAL_LINE;
 973         }
 974
 975         /* Latency format */
 976         if (trace_flags & TRACE_ITER_LATENCY_FMT) {
 977                 ret = print_graph_lat_fmt(s, ent);
 978                 if (ret == TRACE_TYPE_PARTIAL_LINE)
 979                         return TRACE_TYPE_PARTIAL_LINE;
 980         }
 981
 982         return 0;
 983 }
 984
 985 /*
 986  * Entry check for irq code
 987  *
 988  * returns 1 if
 989  *  - we are inside irq code
 990  *  - we just entered irq code
 991  *
 992  * retunns 0 if
 993  *  - funcgraph-interrupts option is set
 994  *  - we are not inside irq code
 995  */
 996 static int
 997 check_irq_entry(struct trace_iterator *iter, u32 flags,
 998                 unsigned long addr, 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 inside the irq code
1017          */
1018         if (*depth_irq >= 0)
1019                 return 1;
1020
1021         if ((addr < (unsigned long)__irqentry_text_start) ||
1022             (addr >= (unsigned long)__irqentry_text_end))
1023                 return 0;
1024
1025         /*
1026          * We are entering irq code.
1027          */
1028         *depth_irq = depth;
1029         return 1;
1030 }
1031
1032 /*
1033  * Return check for irq code
1034  *
1035  * returns 1 if
1036  *  - we are inside irq code
1037  *  - we just left irq code
1038  *
1039  * returns 0 if
1040  *  - funcgraph-interrupts option is set
1041  *  - we are not inside irq code
1042  */
1043 static int
1044 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
1045 {
1046         int cpu = iter->cpu;
1047         int *depth_irq;
1048         struct fgraph_data *data = iter->private;
1049
1050         /*
1051          * If we are either displaying irqs, or we got called as
1052          * a graph event and private data does not exist,
1053          * then we bypass the irq check.
1054          */
1055         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
1056             (!data))
1057                 return 0;
1058
1059         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1060
1061         /*
1062          * We are not inside the irq code.
1063          */
1064         if (*depth_irq == -1)
1065                 return 0;
1066
1067         /*
1068          * We are inside the irq code, and this is returning entry.
1069          * Let's not trace it and clear the entry depth, since
1070          * we are out of irq code.
1071          *
1072          * This condition ensures that we 'leave the irq code' once
1073          * we are out of the entry depth. Thus protecting us from
1074          * the RETURN entry loss.
1075          */
1076         if (*depth_irq >= depth) {
1077                 *depth_irq = -1;
1078                 return 1;
1079         }
1080
1081         /*
1082          * We are inside the irq code, and this is not the entry.
1083          */
1084         return 1;
1085 }
1086
1087 static enum print_line_t
1088 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
1089                         struct trace_iterator *iter, u32 flags)
1090 {
1091         struct fgraph_data *data = iter->private;
1092         struct ftrace_graph_ent *call = &field->graph_ent;
1093         struct ftrace_graph_ret_entry *leaf_ret;
1094         static enum print_line_t ret;
1095         int cpu = iter->cpu;
1096
1097         if (check_irq_entry(iter, flags, call->func, call->depth))
1098                 return TRACE_TYPE_HANDLED;
1099
1100         if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
1101                 return TRACE_TYPE_PARTIAL_LINE;
1102
1103         leaf_ret = get_return_for_leaf(iter, field);
1104         if (leaf_ret)
1105                 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1106         else
1107                 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1108
1109         if (data) {
1110                 /*
1111                  * If we failed to write our output, then we need to make
1112                  * note of it. Because we already consumed our entry.
1113                  */
1114                 if (s->full) {
1115                         data->failed = 1;
1116                         data->cpu = cpu;
1117                 } else
1118                         data->failed = 0;
1119         }
1120
1121         return ret;
1122 }
1123
1124 static enum print_line_t
1125 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1126                    struct trace_entry *ent, struct trace_iterator *iter,
1127                    u32 flags)
1128 {
1129         unsigned long long duration = trace->rettime - trace->calltime;
1130         struct fgraph_data *data = iter->private;
1131         pid_t pid = ent->pid;
1132         int cpu = iter->cpu;
1133         int func_match = 1;
1134         int ret;
1135         int i;
1136
1137         if (check_irq_return(iter, flags, trace->depth))
1138                 return TRACE_TYPE_HANDLED;
1139
1140         if (data) {
1141                 struct fgraph_cpu_data *cpu_data;
1142                 int cpu = iter->cpu;
1143
1144                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1145
1146                 /*
1147                  * Comments display at + 1 to depth. This is the
1148                  * return from a function, we now want the comments
1149                  * to display at the same level of the bracket.
1150                  */
1151                 cpu_data->depth = trace->depth - 1;
1152
1153                 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
1154                         if (cpu_data->enter_funcs[trace->depth] != trace->func)
1155                                 func_match = 0;
1156                         cpu_data->enter_funcs[trace->depth] = 0;
1157                 }
1158         }
1159
1160         if (print_graph_prologue(iter, s, 0, 0, flags))
1161                 return TRACE_TYPE_PARTIAL_LINE;
1162
1163         /* Overhead and duration */
1164         ret = print_graph_duration(duration, s, flags);
1165         if (ret == TRACE_TYPE_PARTIAL_LINE)
1166                 return TRACE_TYPE_PARTIAL_LINE;
1167
1168         /* Closing brace */
1169         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
1170                 ret = trace_seq_putc(s, ' ');
1171                 if (!ret)
1172                         return TRACE_TYPE_PARTIAL_LINE;
1173         }
1174
1175         /*
1176          * If the return function does not have a matching entry,
1177          * then the entry was lost. Instead of just printing
1178          * the '}' and letting the user guess what function this
1179          * belongs to, write out the function name.
1180          */
1181         if (func_match) {
1182                 ret = trace_seq_puts(s, "}\n");
1183                 if (!ret)
1184                         return TRACE_TYPE_PARTIAL_LINE;
1185         } else {
1186                 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1187                 if (!ret)
1188                         return TRACE_TYPE_PARTIAL_LINE;
1189         }
1190
1191         /* Overrun */
1192         if (flags & TRACE_GRAPH_PRINT_OVERRUN) {
1193                 ret = trace_seq_printf(s, " (Overruns: %lu)\n",
1194                                         trace->overrun);
1195                 if (!ret)
1196                         return TRACE_TYPE_PARTIAL_LINE;
1197         }
1198
1199         ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1200                               cpu, pid, flags);
1201         if (ret == TRACE_TYPE_PARTIAL_LINE)
1202                 return TRACE_TYPE_PARTIAL_LINE;
1203
1204         return TRACE_TYPE_HANDLED;
1205 }
1206
1207 static enum print_line_t
1208 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1209                     struct trace_iterator *iter, u32 flags)
1210 {
1211         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1212         struct fgraph_data *data = iter->private;
1213         struct trace_event *event;
1214         int depth = 0;
1215         int ret;
1216         int i;
1217
1218         if (data)
1219                 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1220
1221         if (print_graph_prologue(iter, s, 0, 0, flags))
1222                 return TRACE_TYPE_PARTIAL_LINE;
1223
1224         /* No time */
1225         ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
1226         if (ret != TRACE_TYPE_HANDLED)
1227                 return ret;
1228
1229         /* Indentation */
1230         if (depth > 0)
1231                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
1232                         ret = trace_seq_putc(s, ' ');
1233                         if (!ret)
1234                                 return TRACE_TYPE_PARTIAL_LINE;
1235                 }
1236
1237         /* The comment */
1238         ret = trace_seq_puts(s, "/* ");
1239         if (!ret)
1240                 return TRACE_TYPE_PARTIAL_LINE;
1241
1242         switch (iter->ent->type) {
1243         case TRACE_BPRINT:
1244                 ret = trace_print_bprintk_msg_only(iter);
1245                 if (ret != TRACE_TYPE_HANDLED)
1246                         return ret;
1247                 break;
1248         case TRACE_PRINT:
1249                 ret = trace_print_printk_msg_only(iter);
1250                 if (ret != TRACE_TYPE_HANDLED)
1251                         return ret;
1252                 break;
1253         default:
1254                 event = ftrace_find_event(ent->type);
1255                 if (!event)
1256                         return TRACE_TYPE_UNHANDLED;
1257
1258                 ret = event->funcs->trace(iter, sym_flags, event);
1259                 if (ret != TRACE_TYPE_HANDLED)
1260                         return ret;
1261         }
1262
1263         /* Strip ending newline */
1264         if (s->buffer[s->len - 1] == '\n') {
1265                 s->buffer[s->len - 1] = '\0';
1266                 s->len--;
1267         }
1268
1269         ret = trace_seq_puts(s, " */\n");
1270         if (!ret)
1271                 return TRACE_TYPE_PARTIAL_LINE;
1272
1273         return TRACE_TYPE_HANDLED;
1274 }
1275
1276
1277 enum print_line_t
1278 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1279 {
1280         struct ftrace_graph_ent_entry *field;
1281         struct fgraph_data *data = iter->private;
1282         struct trace_entry *entry = iter->ent;
1283         struct trace_seq *s = &iter->seq;
1284         int cpu = iter->cpu;
1285         int ret;
1286
1287         if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1288                 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1289                 return TRACE_TYPE_HANDLED;
1290         }
1291
1292         /*
1293          * If the last output failed, there's a possibility we need
1294          * to print out the missing entry which would never go out.
1295          */
1296         if (data && data->failed) {
1297                 field = &data->ent;
1298                 iter->cpu = data->cpu;
1299                 ret = print_graph_entry(field, s, iter, flags);
1300                 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1301                         per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1302                         ret = TRACE_TYPE_NO_CONSUME;
1303                 }
1304                 iter->cpu = cpu;
1305                 return ret;
1306         }
1307
1308         switch (entry->type) {
1309         case TRACE_GRAPH_ENT: {
1310                 /*
1311                  * print_graph_entry() may consume the current event,
1312                  * thus @field may become invalid, so we need to save it.
1313                  * sizeof(struct ftrace_graph_ent_entry) is very small,
1314                  * it can be safely saved at the stack.
1315                  */
1316                 struct ftrace_graph_ent_entry saved;
1317                 trace_assign_type(field, entry);
1318                 saved = *field;
1319                 return print_graph_entry(&saved, s, iter, flags);
1320         }
1321         case TRACE_GRAPH_RET: {
1322                 struct ftrace_graph_ret_entry *field;
1323                 trace_assign_type(field, entry);
1324                 return print_graph_return(&field->ret, s, entry, iter, flags);
1325         }
1326         case TRACE_STACK:
1327         case TRACE_FN:
1328                 /* dont trace stack and functions as comments */
1329                 return TRACE_TYPE_UNHANDLED;
1330
1331         default:
1332                 return print_graph_comment(s, entry, iter, flags);
1333         }
1334
1335         return TRACE_TYPE_HANDLED;
1336 }
1337
1338 static enum print_line_t
1339 print_graph_function(struct trace_iterator *iter)
1340 {
1341         return print_graph_function_flags(iter, tracer_flags.val);
1342 }
1343
1344 static enum print_line_t
1345 print_graph_function_event(struct trace_iterator *iter, int flags,
1346                            struct trace_event *event)
1347 {
1348         return print_graph_function(iter);
1349 }
1350
1351 static void print_lat_header(struct seq_file *s, u32 flags)
1352 {
1353         static const char spaces[] = "                " /* 16 spaces */
1354                 "    "                                  /* 4 spaces */
1355                 "                 ";                    /* 17 spaces */
1356         int size = 0;
1357
1358         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1359                 size += 16;
1360         if (flags & TRACE_GRAPH_PRINT_CPU)
1361                 size += 4;
1362         if (flags & TRACE_GRAPH_PRINT_PROC)
1363                 size += 17;
1364
1365         seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
1366         seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
1367         seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1368         seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
1369         seq_printf(s, "#%.*s||| /                      \n", size, spaces);
1370 }
1371
1372 static void __print_graph_headers_flags(struct seq_file *s, u32 flags)
1373 {
1374         int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1375
1376         if (lat)
1377                 print_lat_header(s, flags);
1378
1379         /* 1st line */
1380         seq_printf(s, "#");
1381         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1382                 seq_printf(s, "     TIME       ");
1383         if (flags & TRACE_GRAPH_PRINT_CPU)
1384                 seq_printf(s, " CPU");
1385         if (flags & TRACE_GRAPH_PRINT_PROC)
1386                 seq_printf(s, "  TASK/PID       ");
1387         if (lat)
1388                 seq_printf(s, "||||");
1389         if (flags & TRACE_GRAPH_PRINT_DURATION)
1390                 seq_printf(s, "  DURATION   ");
1391         seq_printf(s, "               FUNCTION CALLS\n");
1392
1393         /* 2nd line */
1394         seq_printf(s, "#");
1395         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1396                 seq_printf(s, "      |         ");
1397         if (flags & TRACE_GRAPH_PRINT_CPU)
1398                 seq_printf(s, " |  ");
1399         if (flags & TRACE_GRAPH_PRINT_PROC)
1400                 seq_printf(s, "   |    |        ");
1401         if (lat)
1402                 seq_printf(s, "||||");
1403         if (flags & TRACE_GRAPH_PRINT_DURATION)
1404                 seq_printf(s, "   |   |      ");
1405         seq_printf(s, "               |   |   |   |\n");
1406 }
1407
1408 void print_graph_headers(struct seq_file *s)
1409 {
1410         print_graph_headers_flags(s, tracer_flags.val);
1411 }
1412
1413 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1414 {
1415         struct trace_iterator *iter = s->private;
1416
1417         if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
1418                 return;
1419
1420         if (trace_flags & TRACE_ITER_LATENCY_FMT) {
1421                 /* print nothing if the buffers are empty */
1422                 if (trace_empty(iter))
1423                         return;
1424
1425                 print_trace_header(s, iter);
1426         }
1427
1428         __print_graph_headers_flags(s, flags);
1429 }
1430
1431 void graph_trace_open(struct trace_iterator *iter)
1432 {
1433         /* pid and depth on the last trace processed */
1434         struct fgraph_data *data;
1435         int cpu;
1436
1437         iter->private = NULL;
1438
1439         data = kzalloc(sizeof(*data), GFP_KERNEL);
1440         if (!data)
1441                 goto out_err;
1442
1443         data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
1444         if (!data->cpu_data)
1445                 goto out_err_free;
1446
1447         for_each_possible_cpu(cpu) {
1448                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1449                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1450                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1451                 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1452
1453                 *pid = -1;
1454                 *depth = 0;
1455                 *ignore = 0;
1456                 *depth_irq = -1;
1457         }
1458
1459         iter->private = data;
1460
1461         return;
1462
1463  out_err_free:
1464         kfree(data);
1465  out_err:
1466         pr_warning("function graph tracer: not enough memory\n");
1467 }
1468
1469 void graph_trace_close(struct trace_iterator *iter)
1470 {
1471         struct fgraph_data *data = iter->private;
1472
1473         if (data) {
1474                 free_percpu(data->cpu_data);
1475                 kfree(data);
1476         }
1477 }
1478
1479 static int func_graph_set_flag(u32 old_flags, u32 bit, int set)
1480 {
1481         if (bit == TRACE_GRAPH_PRINT_IRQS)
1482                 ftrace_graph_skip_irqs = !set;
1483
1484         return 0;
1485 }
1486
1487 static struct trace_event_functions graph_functions = {
1488         .trace          = print_graph_function_event,
1489 };
1490
1491 static struct trace_event graph_trace_entry_event = {
1492         .type           = TRACE_GRAPH_ENT,
1493         .funcs          = &graph_functions,
1494 };
1495
1496 static struct trace_event graph_trace_ret_event = {
1497         .type           = TRACE_GRAPH_RET,
1498         .funcs          = &graph_functions
1499 };
1500
1501 static struct tracer graph_trace __tracer_data = {
1502         .name           = "function_graph",
1503         .open           = graph_trace_open,
1504         .pipe_open      = graph_trace_open,
1505         .close          = graph_trace_close,
1506         .pipe_close     = graph_trace_close,
1507         .wait_pipe      = poll_wait_pipe,
1508         .init           = graph_trace_init,
1509         .reset          = graph_trace_reset,
1510         .print_line     = print_graph_function,
1511         .print_header   = print_graph_headers,
1512         .flags          = &tracer_flags,
1513         .set_flag       = func_graph_set_flag,
1514 #ifdef CONFIG_FTRACE_SELFTEST
1515         .selftest       = trace_selftest_startup_function_graph,
1516 #endif
1517 };
1518
1519
1520 static ssize_t
1521 graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1522                   loff_t *ppos)
1523 {
1524         unsigned long val;
1525         int ret;
1526
1527         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1528         if (ret)
1529                 return ret;
1530
1531         max_depth = val;
1532
1533         *ppos += cnt;
1534
1535         return cnt;
1536 }
1537
1538 static ssize_t
1539 graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1540                  loff_t *ppos)
1541 {
1542         char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1543         int n;
1544
1545         n = sprintf(buf, "%d\n", max_depth);
1546
1547         return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1548 }
1549
1550 static const struct file_operations graph_depth_fops = {
1551         .open           = tracing_open_generic,
1552         .write          = graph_depth_write,
1553         .read           = graph_depth_read,
1554         .llseek         = generic_file_llseek,
1555 };
1556
1557 static __init int init_graph_debugfs(void)
1558 {
1559         struct dentry *d_tracer;
1560
1561         d_tracer = tracing_init_dentry();
1562         if (!d_tracer)
1563                 return 0;
1564
1565         trace_create_file("max_graph_depth", 0644, d_tracer,
1566                           NULL, &graph_depth_fops);
1567
1568         return 0;
1569 }
1570 fs_initcall(init_graph_debugfs);
1571
1572 static __init int init_graph_trace(void)
1573 {
1574         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1575
1576         if (!register_ftrace_event(&graph_trace_entry_event)) {
1577                 pr_warning("Warning: could not register graph trace events\n");
1578                 return 1;
1579         }
1580
1581         if (!register_ftrace_event(&graph_trace_ret_event)) {
1582                 pr_warning("Warning: could not register graph trace events\n");
1583                 return 1;
1584         }
1585
1586         return register_tracer(&graph_trace);
1587 }
1588
1589 core_initcall(init_graph_trace);