kernel/trace/trace_functions_graph.c

   1 /*
   2  *
   3  * Function graph tracer.
   4  * Copyright (c) 2008-2009 Frederic Weisbecker <[email protected]>
   5  * Mostly borrowed from function tracer which
   6  * is Copyright (c) Steven Rostedt <[email protected]>
   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 static bool kill_ftrace_graph;
  19
  20 /**
  21  * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
  22  *
  23  * ftrace_graph_stop() is called when a severe error is detected in
  24  * the function graph tracing. This function is called by the critical
  25  * paths of function graph to keep those paths from doing any more harm.
  26  */
  27 bool ftrace_graph_is_dead(void)
  28 {
  29         return kill_ftrace_graph;
  30 }
  31
  32 /**
  33  * ftrace_graph_stop - set to permanently disable function graph tracincg
  34  *
  35  * In case of an error int function graph tracing, this is called
  36  * to try to keep function graph tracing from causing any more harm.
  37  * Usually this is pretty severe and this is called to try to at least
  38  * get a warning out to the user.
  39  */
  40 void ftrace_graph_stop(void)
  41 {
  42         kill_ftrace_graph = true;
  43 }
  44
  45 /* When set, irq functions will be ignored */
  46 static int ftrace_graph_skip_irqs;
  47
  48 struct fgraph_cpu_data {
  49         pid_t           last_pid;
  50         int             depth;
  51         int             depth_irq;
  52         int             ignore;
  53         unsigned long   enter_funcs[FTRACE_RETFUNC_DEPTH];
  54 };
  55
  56 struct fgraph_data {
  57         struct fgraph_cpu_data __percpu *cpu_data;
  58
  59         /* Place to preserve last processed entry. */
  60         struct ftrace_graph_ent_entry   ent;
  61         struct ftrace_graph_ret_entry   ret;
  62         int                             failed;
  63         int                             cpu;
  64 };
  65
  66 #define TRACE_GRAPH_INDENT      2
  67
  68 static unsigned int max_depth;
  69
  70 static struct tracer_opt trace_opts[] = {
  71         /* Display overruns? (for self-debug purpose) */
  72         { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
  73         /* Display CPU ? */
  74         { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
  75         /* Display Overhead ? */
  76         { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
  77         /* Display proc name/pid */
  78         { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
  79         /* Display duration of execution */
  80         { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
  81         /* Display absolute time of an entry */
  82         { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
  83         /* Display interrupts */
  84         { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
  85         /* Display function name after trailing } */
  86         { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
  87         { } /* Empty entry */
  88 };
  89
  90 static struct tracer_flags tracer_flags = {
  91         /* Don't display overruns, proc, or tail by default */
  92         .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
  93                TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS,
  94         .opts = trace_opts
  95 };
  96
  97 static struct trace_array *graph_array;
  98
  99 /*
 100  * DURATION column is being also used to display IRQ signs,
 101  * following values are used by print_graph_irq and others
 102  * to fill in space into DURATION column.
 103  */
 104 enum {
 105         FLAGS_FILL_FULL  = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 106         FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 107         FLAGS_FILL_END   = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 108 };
 109
 110 static void
 111 print_graph_duration(unsigned long long duration, struct trace_seq *s,
 112                      u32 flags);
 113
 114 /* Add a function return address to the trace stack on thread info.*/
 115 int
 116 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 117                          unsigned long frame_pointer)
 118 {
 119         unsigned long long calltime;
 120         int index;
 121
 122         if (unlikely(ftrace_graph_is_dead()))
 123                 return -EBUSY;
 124
 125         if (!current->ret_stack)
 126                 return -EBUSY;
 127
 128         /*
 129          * We must make sure the ret_stack is tested before we read
 130          * anything else.
 131          */
 132         smp_rmb();
 133
 134         /* The return trace stack is full */
 135         if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
 136                 atomic_inc(&current->trace_overrun);
 137                 return -EBUSY;
 138         }
 139
 140         /*
 141          * The curr_ret_stack is an index to ftrace return stack of
 142          * current task.  Its value should be in [0, FTRACE_RETFUNC_
 143          * DEPTH) when the function graph tracer is used.  To support
 144          * filtering out specific functions, it makes the index
 145          * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
 146          * so when it sees a negative index the ftrace will ignore
 147          * the record.  And the index gets recovered when returning
 148          * from the filtered function by adding the FTRACE_NOTRACE_
 149          * DEPTH and then it'll continue to record functions normally.
 150          *
 151          * The curr_ret_stack is initialized to -1 and get increased
 152          * in this function.  So it can be less than -1 only if it was
 153          * filtered out via ftrace_graph_notrace_addr() which can be
 154          * set from set_graph_notrace file in debugfs by user.
 155          */
 156         if (current->curr_ret_stack < -1)
 157                 return -EBUSY;
 158
 159         calltime = trace_clock_local();
 160
 161         index = ++current->curr_ret_stack;
 162         if (ftrace_graph_notrace_addr(func))
 163                 current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
 164         barrier();
 165         current->ret_stack[index].ret = ret;
 166         current->ret_stack[index].func = func;
 167         current->ret_stack[index].calltime = calltime;
 168         current->ret_stack[index].subtime = 0;
 169         current->ret_stack[index].fp = frame_pointer;
 170         *depth = current->curr_ret_stack;
 171
 172         return 0;
 173 }
 174
 175 /* Retrieve a function return address to the trace stack on thread info.*/
 176 static void
 177 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
 178                         unsigned long frame_pointer)
 179 {
 180         int index;
 181
 182         index = current->curr_ret_stack;
 183
 184         /*
 185          * A negative index here means that it's just returned from a
 186          * notrace'd function.  Recover index to get an original
 187          * return address.  See ftrace_push_return_trace().
 188          *
 189          * TODO: Need to check whether the stack gets corrupted.
 190          */
 191         if (index < 0)
 192                 index += FTRACE_NOTRACE_DEPTH;
 193
 194         if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
 195                 ftrace_graph_stop();
 196                 WARN_ON(1);
 197                 /* Might as well panic, otherwise we have no where to go */
 198                 *ret = (unsigned long)panic;
 199                 return;
 200         }
 201
 202 #if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY)
 203         /*
 204          * The arch may choose to record the frame pointer used
 205          * and check it here to make sure that it is what we expect it
 206          * to be. If gcc does not set the place holder of the return
 207          * address in the frame pointer, and does a copy instead, then
 208          * the function graph trace will fail. This test detects this
 209          * case.
 210          *
 211          * Currently, x86_32 with optimize for size (-Os) makes the latest
 212          * gcc do the above.
 213          *
 214          * Note, -mfentry does not use frame pointers, and this test
 215          *  is not needed if CC_USING_FENTRY is set.
 216          */
 217         if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
 218                 ftrace_graph_stop();
 219                 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
 220                      "  from func %ps return to %lx\n",
 221                      current->ret_stack[index].fp,
 222                      frame_pointer,
 223                      (void *)current->ret_stack[index].func,
 224                      current->ret_stack[index].ret);
 225                 *ret = (unsigned long)panic;
 226                 return;
 227         }
 228 #endif
 229
 230         *ret = current->ret_stack[index].ret;
 231         trace->func = current->ret_stack[index].func;
 232         trace->calltime = current->ret_stack[index].calltime;
 233         trace->overrun = atomic_read(&current->trace_overrun);
 234         trace->depth = index;
 235 }
 236
 237 /*
 238  * Send the trace to the ring-buffer.
 239  * @return the original return address.
 240  */
 241 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 242 {
 243         struct ftrace_graph_ret trace;
 244         unsigned long ret;
 245
 246         ftrace_pop_return_trace(&trace, &ret, frame_pointer);
 247         trace.rettime = trace_clock_local();
 248         barrier();
 249         current->curr_ret_stack--;
 250         /*
 251          * The curr_ret_stack can be less than -1 only if it was
 252          * filtered out and it's about to return from the function.
 253          * Recover the index and continue to trace normal functions.
 254          */
 255         if (current->curr_ret_stack < -1) {
 256                 current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
 257                 return ret;
 258         }
 259
 260         /*
 261          * The trace should run after decrementing the ret counter
 262          * in case an interrupt were to come in. We don't want to
 263          * lose the interrupt if max_depth is set.
 264          */
 265         ftrace_graph_return(&trace);
 266
 267         if (unlikely(!ret)) {
 268                 ftrace_graph_stop();
 269                 WARN_ON(1);
 270                 /* Might as well panic. What else to do? */
 271                 ret = (unsigned long)panic;
 272         }
 273
 274         return ret;
 275 }
 276
 277 int __trace_graph_entry(struct trace_array *tr,
 278                                 struct ftrace_graph_ent *trace,
 279                                 unsigned long flags,
 280                                 int pc)
 281 {
 282         struct ftrace_event_call *call = &event_funcgraph_entry;
 283         struct ring_buffer_event *event;
 284         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 285         struct ftrace_graph_ent_entry *entry;
 286
 287         if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
 288                 return 0;
 289
 290         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
 291                                           sizeof(*entry), flags, pc);
 292         if (!event)
 293                 return 0;
 294         entry   = ring_buffer_event_data(event);
 295         entry->graph_ent                        = *trace;
 296         if (!call_filter_check_discard(call, entry, buffer, event))
 297                 __buffer_unlock_commit(buffer, event);
 298
 299         return 1;
 300 }
 301
 302 static inline int ftrace_graph_ignore_irqs(void)
 303 {
 304         if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
 305                 return 0;
 306
 307         return in_irq();
 308 }
 309
 310 int trace_graph_entry(struct ftrace_graph_ent *trace)
 311 {
 312         struct trace_array *tr = graph_array;
 313         struct trace_array_cpu *data;
 314         unsigned long flags;
 315         long disabled;
 316         int ret;
 317         int cpu;
 318         int pc;
 319
 320         if (!ftrace_trace_task(current))
 321                 return 0;
 322
 323         /* trace it when it is-nested-in or is a function enabled. */
 324         if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
 325              ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
 326             (max_depth && trace->depth >= max_depth))
 327                 return 0;
 328
 329         /*
 330          * Do not trace a function if it's filtered by set_graph_notrace.
 331          * Make the index of ret stack negative to indicate that it should
 332          * ignore further functions.  But it needs its own ret stack entry
 333          * to recover the original index in order to continue tracing after
 334          * returning from the function.
 335          */
 336         if (ftrace_graph_notrace_addr(trace->func))
 337                 return 1;
 338
 339         local_irq_save(flags);
 340         cpu = raw_smp_processor_id();
 341         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 342         disabled = atomic_inc_return(&data->disabled);
 343         if (likely(disabled == 1)) {
 344                 pc = preempt_count();
 345                 ret = __trace_graph_entry(tr, trace, flags, pc);
 346         } else {
 347                 ret = 0;
 348         }
 349
 350         atomic_dec(&data->disabled);
 351         local_irq_restore(flags);
 352
 353         return ret;
 354 }
 355
 356 static int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
 357 {
 358         if (tracing_thresh)
 359                 return 1;
 360         else
 361                 return trace_graph_entry(trace);
 362 }
 363
 364 static void
 365 __trace_graph_function(struct trace_array *tr,
 366                 unsigned long ip, unsigned long flags, int pc)
 367 {
 368         u64 time = trace_clock_local();
 369         struct ftrace_graph_ent ent = {
 370                 .func  = ip,
 371                 .depth = 0,
 372         };
 373         struct ftrace_graph_ret ret = {
 374                 .func     = ip,
 375                 .depth    = 0,
 376                 .calltime = time,
 377                 .rettime  = time,
 378         };
 379
 380         __trace_graph_entry(tr, &ent, flags, pc);
 381         __trace_graph_return(tr, &ret, flags, pc);
 382 }
 383
 384 void
 385 trace_graph_function(struct trace_array *tr,
 386                 unsigned long ip, unsigned long parent_ip,
 387                 unsigned long flags, int pc)
 388 {
 389         __trace_graph_function(tr, ip, flags, pc);
 390 }
 391
 392 void __trace_graph_return(struct trace_array *tr,
 393                                 struct ftrace_graph_ret *trace,
 394                                 unsigned long flags,
 395                                 int pc)
 396 {
 397         struct ftrace_event_call *call = &event_funcgraph_exit;
 398         struct ring_buffer_event *event;
 399         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 400         struct ftrace_graph_ret_entry *entry;
 401
 402         if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
 403                 return;
 404
 405         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
 406                                           sizeof(*entry), flags, pc);
 407         if (!event)
 408                 return;
 409         entry   = ring_buffer_event_data(event);
 410         entry->ret                              = *trace;
 411         if (!call_filter_check_discard(call, entry, buffer, event))
 412                 __buffer_unlock_commit(buffer, event);
 413 }
 414
 415 void trace_graph_return(struct ftrace_graph_ret *trace)
 416 {
 417         struct trace_array *tr = graph_array;
 418         struct trace_array_cpu *data;
 419         unsigned long flags;
 420         long disabled;
 421         int cpu;
 422         int pc;
 423
 424         local_irq_save(flags);
 425         cpu = raw_smp_processor_id();
 426         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 427         disabled = atomic_inc_return(&data->disabled);
 428         if (likely(disabled == 1)) {
 429                 pc = preempt_count();
 430                 __trace_graph_return(tr, trace, flags, pc);
 431         }
 432         atomic_dec(&data->disabled);
 433         local_irq_restore(flags);
 434 }
 435
 436 void set_graph_array(struct trace_array *tr)
 437 {
 438         graph_array = tr;
 439
 440         /* Make graph_array visible before we start tracing */
 441
 442         smp_mb();
 443 }
 444
 445 static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 446 {
 447         if (tracing_thresh &&
 448             (trace->rettime - trace->calltime < tracing_thresh))
 449                 return;
 450         else
 451                 trace_graph_return(trace);
 452 }
 453
 454 static int graph_trace_init(struct trace_array *tr)
 455 {
 456         int ret;
 457
 458         set_graph_array(tr);
 459         if (tracing_thresh)
 460                 ret = register_ftrace_graph(&trace_graph_thresh_return,
 461                                             &trace_graph_thresh_entry);
 462         else
 463                 ret = register_ftrace_graph(&trace_graph_return,
 464                                             &trace_graph_entry);
 465         if (ret)
 466                 return ret;
 467         tracing_start_cmdline_record();
 468
 469         return 0;
 470 }
 471
 472 static void graph_trace_reset(struct trace_array *tr)
 473 {
 474         tracing_stop_cmdline_record();
 475         unregister_ftrace_graph();
 476 }
 477
 478 static int graph_trace_update_thresh(struct trace_array *tr)
 479 {
 480         graph_trace_reset(tr);
 481         return graph_trace_init(tr);
 482 }
 483
 484 static int max_bytes_for_cpu;
 485
 486 static void print_graph_cpu(struct trace_seq *s, int cpu)
 487 {
 488         /*
 489          * Start with a space character - to make it stand out
 490          * to the right a bit when trace output is pasted into
 491          * email:
 492          */
 493         trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 494 }
 495
 496 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 497
 498 static void print_graph_proc(struct trace_seq *s, pid_t pid)
 499 {
 500         char comm[TASK_COMM_LEN];
 501         /* sign + log10(MAX_INT) + '\0' */
 502         char pid_str[11];
 503         int spaces = 0;
 504         int len;
 505         int i;
 506
 507         trace_find_cmdline(pid, comm);
 508         comm[7] = '\0';
 509         sprintf(pid_str, "%d", pid);
 510
 511         /* 1 stands for the "-" character */
 512         len = strlen(comm) + strlen(pid_str) + 1;
 513
 514         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 515                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 516
 517         /* First spaces to align center */
 518         for (i = 0; i < spaces / 2; i++)
 519                 trace_seq_putc(s, ' ');
 520
 521         trace_seq_printf(s, "%s-%s", comm, pid_str);
 522
 523         /* Last spaces to align center */
 524         for (i = 0; i < spaces - (spaces / 2); i++)
 525                 trace_seq_putc(s, ' ');
 526 }
 527
 528
 529 static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 530 {
 531         trace_seq_putc(s, ' ');
 532         trace_print_lat_fmt(s, entry);
 533 }
 534
 535 /* If the pid changed since the last trace, output this event */
 536 static void
 537 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 538 {
 539         pid_t prev_pid;
 540         pid_t *last_pid;
 541
 542         if (!data)
 543                 return;
 544
 545         last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
 546
 547         if (*last_pid == pid)
 548                 return;
 549
 550         prev_pid = *last_pid;
 551         *last_pid = pid;
 552
 553         if (prev_pid == -1)
 554                 return;
 555 /*
 556  * Context-switch trace line:
 557
 558  ------------------------------------------
 559  | 1)  migration/0--1  =>  sshd-1755
 560  ------------------------------------------
 561
 562  */
 563         trace_seq_puts(s, " ------------------------------------------\n");
 564         print_graph_cpu(s, cpu);
 565         print_graph_proc(s, prev_pid);
 566         trace_seq_puts(s, " => ");
 567         print_graph_proc(s, pid);
 568         trace_seq_puts(s, "\n ------------------------------------------\n\n");
 569 }
 570
 571 static struct ftrace_graph_ret_entry *
 572 get_return_for_leaf(struct trace_iterator *iter,
 573                 struct ftrace_graph_ent_entry *curr)
 574 {
 575         struct fgraph_data *data = iter->private;
 576         struct ring_buffer_iter *ring_iter = NULL;
 577         struct ring_buffer_event *event;
 578         struct ftrace_graph_ret_entry *next;
 579
 580         /*
 581          * If the previous output failed to write to the seq buffer,
 582          * then we just reuse the data from before.
 583          */
 584         if (data && data->failed) {
 585                 curr = &data->ent;
 586                 next = &data->ret;
 587         } else {
 588
 589                 ring_iter = trace_buffer_iter(iter, iter->cpu);
 590
 591                 /* First peek to compare current entry and the next one */
 592                 if (ring_iter)
 593                         event = ring_buffer_iter_peek(ring_iter, NULL);
 594                 else {
 595                         /*
 596                          * We need to consume the current entry to see
 597                          * the next one.
 598                          */
 599                         ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
 600                                             NULL, NULL);
 601                         event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
 602                                                  NULL, NULL);
 603                 }
 604
 605                 if (!event)
 606                         return NULL;
 607
 608                 next = ring_buffer_event_data(event);
 609
 610                 if (data) {
 611                         /*
 612                          * Save current and next entries for later reference
 613                          * if the output fails.
 614                          */
 615                         data->ent = *curr;
 616                         /*
 617                          * If the next event is not a return type, then
 618                          * we only care about what type it is. Otherwise we can
 619                          * safely copy the entire event.
 620                          */
 621                         if (next->ent.type == TRACE_GRAPH_RET)
 622                                 data->ret = *next;
 623                         else
 624                                 data->ret.ent.type = next->ent.type;
 625                 }
 626         }
 627
 628         if (next->ent.type != TRACE_GRAPH_RET)
 629                 return NULL;
 630
 631         if (curr->ent.pid != next->ent.pid ||
 632                         curr->graph_ent.func != next->ret.func)
 633                 return NULL;
 634
 635         /* this is a leaf, now advance the iterator */
 636         if (ring_iter)
 637                 ring_buffer_read(ring_iter, NULL);
 638
 639         return next;
 640 }
 641
 642 static void print_graph_abs_time(u64 t, struct trace_seq *s)
 643 {
 644         unsigned long usecs_rem;
 645
 646         usecs_rem = do_div(t, NSEC_PER_SEC);
 647         usecs_rem /= 1000;
 648
 649         trace_seq_printf(s, "%5lu.%06lu |  ",
 650                          (unsigned long)t, usecs_rem);
 651 }
 652
 653 static void
 654 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 655                 enum trace_type type, int cpu, pid_t pid, u32 flags)
 656 {
 657         struct trace_seq *s = &iter->seq;
 658         struct trace_entry *ent = iter->ent;
 659
 660         if (addr < (unsigned long)__irqentry_text_start ||
 661                 addr >= (unsigned long)__irqentry_text_end)
 662                 return;
 663
 664         if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
 665                 /* Absolute time */
 666                 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 667                         print_graph_abs_time(iter->ts, s);
 668
 669                 /* Cpu */
 670                 if (flags & TRACE_GRAPH_PRINT_CPU)
 671                         print_graph_cpu(s, cpu);
 672
 673                 /* Proc */
 674                 if (flags & TRACE_GRAPH_PRINT_PROC) {
 675                         print_graph_proc(s, pid);
 676                         trace_seq_puts(s, " | ");
 677                 }
 678
 679                 /* Latency format */
 680                 if (trace_flags & TRACE_ITER_LATENCY_FMT)
 681                         print_graph_lat_fmt(s, ent);
 682         }
 683
 684         /* No overhead */
 685         print_graph_duration(0, s, flags | FLAGS_FILL_START);
 686
 687         if (type == TRACE_GRAPH_ENT)
 688                 trace_seq_puts(s, "==========>");
 689         else
 690                 trace_seq_puts(s, "<==========");
 691
 692         print_graph_duration(0, s, flags | FLAGS_FILL_END);
 693         trace_seq_putc(s, '\n');
 694 }
 695
 696 void
 697 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 698 {
 699         unsigned long nsecs_rem = do_div(duration, 1000);
 700         /* log10(ULONG_MAX) + '\0' */
 701         char usecs_str[21];
 702         char nsecs_str[5];
 703         int len;
 704         int i;
 705
 706         sprintf(usecs_str, "%lu", (unsigned long) duration);
 707
 708         /* Print msecs */
 709         trace_seq_printf(s, "%s", usecs_str);
 710
 711         len = strlen(usecs_str);
 712
 713         /* Print nsecs (we don't want to exceed 7 numbers) */
 714         if (len < 7) {
 715                 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
 716
 717                 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
 718                 trace_seq_printf(s, ".%s", nsecs_str);
 719                 len += strlen(nsecs_str);
 720         }
 721
 722         trace_seq_puts(s, " us ");
 723
 724         /* Print remaining spaces to fit the row's width */
 725         for (i = len; i < 7; i++)
 726                 trace_seq_putc(s, ' ');
 727 }
 728
 729 static void
 730 print_graph_duration(unsigned long long duration, struct trace_seq *s,
 731                      u32 flags)
 732 {
 733         bool duration_printed = false;
 734
 735         if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
 736             !(trace_flags & TRACE_ITER_CONTEXT_INFO))
 737                 return;
 738
 739         /* No real adata, just filling the column with spaces */
 740         switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
 741         case FLAGS_FILL_FULL:
 742                 trace_seq_puts(s, "              |  ");
 743                 return;
 744         case FLAGS_FILL_START:
 745                 trace_seq_puts(s, "  ");
 746                 return;
 747         case FLAGS_FILL_END:
 748                 trace_seq_puts(s, " |");
 749                 return;
 750         }
 751
 752         /* Signal a overhead of time execution to the output */
 753         if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
 754                 /* Duration exceeded 100 usecs */
 755                 if (duration > 100000ULL) {
 756                         trace_seq_puts(s, "! ");
 757                         duration_printed = true;
 758
 759                 /* Duration exceeded 10 usecs */
 760                 } else if (duration > 10000ULL) {
 761                         trace_seq_puts(s, "+ ");
 762                         duration_printed = true;
 763                 }
 764         }
 765
 766         /*
 767          * If we did not exceed the duration tresholds or we dont want
 768          * to print out the overhead. Either way we need to fill out the space.
 769          */
 770         if (!duration_printed)
 771                 trace_seq_puts(s, "  ");
 772
 773         trace_print_graph_duration(duration, s);
 774         trace_seq_puts(s, "|  ");
 775 }
 776
 777 /* Case of a leaf function on its call entry */
 778 static enum print_line_t
 779 print_graph_entry_leaf(struct trace_iterator *iter,
 780                 struct ftrace_graph_ent_entry *entry,
 781                 struct ftrace_graph_ret_entry *ret_entry,
 782                 struct trace_seq *s, u32 flags)
 783 {
 784         struct fgraph_data *data = iter->private;
 785         struct ftrace_graph_ret *graph_ret;
 786         struct ftrace_graph_ent *call;
 787         unsigned long long duration;
 788         int i;
 789
 790         graph_ret = &ret_entry->ret;
 791         call = &entry->graph_ent;
 792         duration = graph_ret->rettime - graph_ret->calltime;
 793
 794         if (data) {
 795                 struct fgraph_cpu_data *cpu_data;
 796                 int cpu = iter->cpu;
 797
 798                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 799
 800                 /*
 801                  * Comments display at + 1 to depth. Since
 802                  * this is a leaf function, keep the comments
 803                  * equal to this depth.
 804                  */
 805                 cpu_data->depth = call->depth - 1;
 806
 807                 /* No need to keep this function around for this depth */
 808                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 809                         cpu_data->enter_funcs[call->depth] = 0;
 810         }
 811
 812         /* Overhead and duration */
 813         print_graph_duration(duration, s, flags);
 814
 815         /* Function */
 816         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
 817                 trace_seq_putc(s, ' ');
 818
 819         trace_seq_printf(s, "%ps();\n", (void *)call->func);
 820
 821         return trace_handle_return(s);
 822 }
 823
 824 static enum print_line_t
 825 print_graph_entry_nested(struct trace_iterator *iter,
 826                          struct ftrace_graph_ent_entry *entry,
 827                          struct trace_seq *s, int cpu, u32 flags)
 828 {
 829         struct ftrace_graph_ent *call = &entry->graph_ent;
 830         struct fgraph_data *data = iter->private;
 831         int i;
 832
 833         if (data) {
 834                 struct fgraph_cpu_data *cpu_data;
 835                 int cpu = iter->cpu;
 836
 837                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 838                 cpu_data->depth = call->depth;
 839
 840                 /* Save this function pointer to see if the exit matches */
 841                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 842                         cpu_data->enter_funcs[call->depth] = call->func;
 843         }
 844
 845         /* No time */
 846         print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
 847
 848         /* Function */
 849         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
 850                 trace_seq_putc(s, ' ');
 851
 852         trace_seq_printf(s, "%ps() {\n", (void *)call->func);
 853
 854         if (trace_seq_has_overflowed(s))
 855                 return TRACE_TYPE_PARTIAL_LINE;
 856
 857         /*
 858          * we already consumed the current entry to check the next one
 859          * and see if this is a leaf.
 860          */
 861         return TRACE_TYPE_NO_CONSUME;
 862 }
 863
 864 static void
 865 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 866                      int type, unsigned long addr, u32 flags)
 867 {
 868         struct fgraph_data *data = iter->private;
 869         struct trace_entry *ent = iter->ent;
 870         int cpu = iter->cpu;
 871
 872         /* Pid */
 873         verif_pid(s, ent->pid, cpu, data);
 874
 875         if (type)
 876                 /* Interrupt */
 877                 print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
 878
 879         if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
 880                 return;
 881
 882         /* Absolute time */
 883         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 884                 print_graph_abs_time(iter->ts, s);
 885
 886         /* Cpu */
 887         if (flags & TRACE_GRAPH_PRINT_CPU)
 888                 print_graph_cpu(s, cpu);
 889
 890         /* Proc */
 891         if (flags & TRACE_GRAPH_PRINT_PROC) {
 892                 print_graph_proc(s, ent->pid);
 893                 trace_seq_puts(s, " | ");
 894         }
 895
 896         /* Latency format */
 897         if (trace_flags & TRACE_ITER_LATENCY_FMT)
 898                 print_graph_lat_fmt(s, ent);
 899
 900         return;
 901 }
 902
 903 /*
 904  * Entry check for irq code
 905  *
 906  * returns 1 if
 907  *  - we are inside irq code
 908  *  - we just entered irq code
 909  *
 910  * retunns 0 if
 911  *  - funcgraph-interrupts option is set
 912  *  - we are not inside irq code
 913  */
 914 static int
 915 check_irq_entry(struct trace_iterator *iter, u32 flags,
 916                 unsigned long addr, int depth)
 917 {
 918         int cpu = iter->cpu;
 919         int *depth_irq;
 920         struct fgraph_data *data = iter->private;
 921
 922         /*
 923          * If we are either displaying irqs, or we got called as
 924          * a graph event and private data does not exist,
 925          * then we bypass the irq check.
 926          */
 927         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
 928             (!data))
 929                 return 0;
 930
 931         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 932
 933         /*
 934          * We are inside the irq code
 935          */
 936         if (*depth_irq >= 0)
 937                 return 1;
 938
 939         if ((addr < (unsigned long)__irqentry_text_start) ||
 940             (addr >= (unsigned long)__irqentry_text_end))
 941                 return 0;
 942
 943         /*
 944          * We are entering irq code.
 945          */
 946         *depth_irq = depth;
 947         return 1;
 948 }
 949
 950 /*
 951  * Return check for irq code
 952  *
 953  * returns 1 if
 954  *  - we are inside irq code
 955  *  - we just left irq code
 956  *
 957  * returns 0 if
 958  *  - funcgraph-interrupts option is set
 959  *  - we are not inside irq code
 960  */
 961 static int
 962 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
 963 {
 964         int cpu = iter->cpu;
 965         int *depth_irq;
 966         struct fgraph_data *data = iter->private;
 967
 968         /*
 969          * If we are either displaying irqs, or we got called as
 970          * a graph event and private data does not exist,
 971          * then we bypass the irq check.
 972          */
 973         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
 974             (!data))
 975                 return 0;
 976
 977         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 978
 979         /*
 980          * We are not inside the irq code.
 981          */
 982         if (*depth_irq == -1)
 983                 return 0;
 984
 985         /*
 986          * We are inside the irq code, and this is returning entry.
 987          * Let's not trace it and clear the entry depth, since
 988          * we are out of irq code.
 989          *
 990          * This condition ensures that we 'leave the irq code' once
 991          * we are out of the entry depth. Thus protecting us from
 992          * the RETURN entry loss.
 993          */
 994         if (*depth_irq >= depth) {
 995                 *depth_irq = -1;
 996                 return 1;
 997         }
 998
 999         /*
1000          * We are inside the irq code, and this is not the entry.
1001          */
1002         return 1;
1003 }
1004
1005 static enum print_line_t
1006 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
1007                         struct trace_iterator *iter, u32 flags)
1008 {
1009         struct fgraph_data *data = iter->private;
1010         struct ftrace_graph_ent *call = &field->graph_ent;
1011         struct ftrace_graph_ret_entry *leaf_ret;
1012         static enum print_line_t ret;
1013         int cpu = iter->cpu;
1014
1015         if (check_irq_entry(iter, flags, call->func, call->depth))
1016                 return TRACE_TYPE_HANDLED;
1017
1018         print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
1019
1020         leaf_ret = get_return_for_leaf(iter, field);
1021         if (leaf_ret)
1022                 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1023         else
1024                 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1025
1026         if (data) {
1027                 /*
1028                  * If we failed to write our output, then we need to make
1029                  * note of it. Because we already consumed our entry.
1030                  */
1031                 if (s->full) {
1032                         data->failed = 1;
1033                         data->cpu = cpu;
1034                 } else
1035                         data->failed = 0;
1036         }
1037
1038         return ret;
1039 }
1040
1041 static enum print_line_t
1042 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1043                    struct trace_entry *ent, struct trace_iterator *iter,
1044                    u32 flags)
1045 {
1046         unsigned long long duration = trace->rettime - trace->calltime;
1047         struct fgraph_data *data = iter->private;
1048         pid_t pid = ent->pid;
1049         int cpu = iter->cpu;
1050         int func_match = 1;
1051         int i;
1052
1053         if (check_irq_return(iter, flags, trace->depth))
1054                 return TRACE_TYPE_HANDLED;
1055
1056         if (data) {
1057                 struct fgraph_cpu_data *cpu_data;
1058                 int cpu = iter->cpu;
1059
1060                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1061
1062                 /*
1063                  * Comments display at + 1 to depth. This is the
1064                  * return from a function, we now want the comments
1065                  * to display at the same level of the bracket.
1066                  */
1067                 cpu_data->depth = trace->depth - 1;
1068
1069                 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
1070                         if (cpu_data->enter_funcs[trace->depth] != trace->func)
1071                                 func_match = 0;
1072                         cpu_data->enter_funcs[trace->depth] = 0;
1073                 }
1074         }
1075
1076         print_graph_prologue(iter, s, 0, 0, flags);
1077
1078         /* Overhead and duration */
1079         print_graph_duration(duration, s, flags);
1080
1081         /* Closing brace */
1082         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
1083                 trace_seq_putc(s, ' ');
1084
1085         /*
1086          * If the return function does not have a matching entry,
1087          * then the entry was lost. Instead of just printing
1088          * the '}' and letting the user guess what function this
1089          * belongs to, write out the function name. Always do
1090          * that if the funcgraph-tail option is enabled.
1091          */
1092         if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
1093                 trace_seq_puts(s, "}\n");
1094         else
1095                 trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1096
1097         /* Overrun */
1098         if (flags & TRACE_GRAPH_PRINT_OVERRUN)
1099                 trace_seq_printf(s, " (Overruns: %lu)\n",
1100                                  trace->overrun);
1101
1102         print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1103                         cpu, pid, flags);
1104
1105         return trace_handle_return(s);
1106 }
1107
1108 static enum print_line_t
1109 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1110                     struct trace_iterator *iter, u32 flags)
1111 {
1112         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1113         struct fgraph_data *data = iter->private;
1114         struct trace_event *event;
1115         int depth = 0;
1116         int ret;
1117         int i;
1118
1119         if (data)
1120                 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1121
1122         print_graph_prologue(iter, s, 0, 0, flags);
1123
1124         /* No time */
1125         print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
1126
1127         /* Indentation */
1128         if (depth > 0)
1129                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
1130                         trace_seq_putc(s, ' ');
1131
1132         /* The comment */
1133         trace_seq_puts(s, "/* ");
1134
1135         switch (iter->ent->type) {
1136         case TRACE_BPRINT:
1137                 ret = trace_print_bprintk_msg_only(iter);
1138                 if (ret != TRACE_TYPE_HANDLED)
1139                         return ret;
1140                 break;
1141         case TRACE_PRINT:
1142                 ret = trace_print_printk_msg_only(iter);
1143                 if (ret != TRACE_TYPE_HANDLED)
1144                         return ret;
1145                 break;
1146         default:
1147                 event = ftrace_find_event(ent->type);
1148                 if (!event)
1149                         return TRACE_TYPE_UNHANDLED;
1150
1151                 ret = event->funcs->trace(iter, sym_flags, event);
1152                 if (ret != TRACE_TYPE_HANDLED)
1153                         return ret;
1154         }
1155
1156         if (trace_seq_has_overflowed(s))
1157                 goto out;
1158
1159         /* Strip ending newline */
1160         if (s->buffer[s->seq.len - 1] == '\n') {
1161                 s->buffer[s->seq.len - 1] = '\0';
1162                 s->seq.len--;
1163         }
1164
1165         trace_seq_puts(s, " */\n");
1166  out:
1167         return trace_handle_return(s);
1168 }
1169
1170
1171 enum print_line_t
1172 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1173 {
1174         struct ftrace_graph_ent_entry *field;
1175         struct fgraph_data *data = iter->private;
1176         struct trace_entry *entry = iter->ent;
1177         struct trace_seq *s = &iter->seq;
1178         int cpu = iter->cpu;
1179         int ret;
1180
1181         if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1182                 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1183                 return TRACE_TYPE_HANDLED;
1184         }
1185
1186         /*
1187          * If the last output failed, there's a possibility we need
1188          * to print out the missing entry which would never go out.
1189          */
1190         if (data && data->failed) {
1191                 field = &data->ent;
1192                 iter->cpu = data->cpu;
1193                 ret = print_graph_entry(field, s, iter, flags);
1194                 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1195                         per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1196                         ret = TRACE_TYPE_NO_CONSUME;
1197                 }
1198                 iter->cpu = cpu;
1199                 return ret;
1200         }
1201
1202         switch (entry->type) {
1203         case TRACE_GRAPH_ENT: {
1204                 /*
1205                  * print_graph_entry() may consume the current event,
1206                  * thus @field may become invalid, so we need to save it.
1207                  * sizeof(struct ftrace_graph_ent_entry) is very small,
1208                  * it can be safely saved at the stack.
1209                  */
1210                 struct ftrace_graph_ent_entry saved;
1211                 trace_assign_type(field, entry);
1212                 saved = *field;
1213                 return print_graph_entry(&saved, s, iter, flags);
1214         }
1215         case TRACE_GRAPH_RET: {
1216                 struct ftrace_graph_ret_entry *field;
1217                 trace_assign_type(field, entry);
1218                 return print_graph_return(&field->ret, s, entry, iter, flags);
1219         }
1220         case TRACE_STACK:
1221         case TRACE_FN:
1222                 /* dont trace stack and functions as comments */
1223                 return TRACE_TYPE_UNHANDLED;
1224
1225         default:
1226                 return print_graph_comment(s, entry, iter, flags);
1227         }
1228
1229         return TRACE_TYPE_HANDLED;
1230 }
1231
1232 static enum print_line_t
1233 print_graph_function(struct trace_iterator *iter)
1234 {
1235         return print_graph_function_flags(iter, tracer_flags.val);
1236 }
1237
1238 static enum print_line_t
1239 print_graph_function_event(struct trace_iterator *iter, int flags,
1240                            struct trace_event *event)
1241 {
1242         return print_graph_function(iter);
1243 }
1244
1245 static void print_lat_header(struct seq_file *s, u32 flags)
1246 {
1247         static const char spaces[] = "                " /* 16 spaces */
1248                 "    "                                  /* 4 spaces */
1249                 "                 ";                    /* 17 spaces */
1250         int size = 0;
1251
1252         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1253                 size += 16;
1254         if (flags & TRACE_GRAPH_PRINT_CPU)
1255                 size += 4;
1256         if (flags & TRACE_GRAPH_PRINT_PROC)
1257                 size += 17;
1258
1259         seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
1260         seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
1261         seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1262         seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
1263         seq_printf(s, "#%.*s||| /                      \n", size, spaces);
1264 }
1265
1266 static void __print_graph_headers_flags(struct seq_file *s, u32 flags)
1267 {
1268         int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1269
1270         if (lat)
1271                 print_lat_header(s, flags);
1272
1273         /* 1st line */
1274         seq_putc(s, '#');
1275         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1276                 seq_puts(s, "     TIME       ");
1277         if (flags & TRACE_GRAPH_PRINT_CPU)
1278                 seq_puts(s, " CPU");
1279         if (flags & TRACE_GRAPH_PRINT_PROC)
1280                 seq_puts(s, "  TASK/PID       ");
1281         if (lat)
1282                 seq_puts(s, "||||");
1283         if (flags & TRACE_GRAPH_PRINT_DURATION)
1284                 seq_puts(s, "  DURATION   ");
1285         seq_puts(s, "               FUNCTION CALLS\n");
1286
1287         /* 2nd line */
1288         seq_putc(s, '#');
1289         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1290                 seq_puts(s, "      |         ");
1291         if (flags & TRACE_GRAPH_PRINT_CPU)
1292                 seq_puts(s, " |  ");
1293         if (flags & TRACE_GRAPH_PRINT_PROC)
1294                 seq_puts(s, "   |    |        ");
1295         if (lat)
1296                 seq_puts(s, "||||");
1297         if (flags & TRACE_GRAPH_PRINT_DURATION)
1298                 seq_puts(s, "   |   |      ");
1299         seq_puts(s, "               |   |   |   |\n");
1300 }
1301
1302 static void print_graph_headers(struct seq_file *s)
1303 {
1304         print_graph_headers_flags(s, tracer_flags.val);
1305 }
1306
1307 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1308 {
1309         struct trace_iterator *iter = s->private;
1310
1311         if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
1312                 return;
1313
1314         if (trace_flags & TRACE_ITER_LATENCY_FMT) {
1315                 /* print nothing if the buffers are empty */
1316                 if (trace_empty(iter))
1317                         return;
1318
1319                 print_trace_header(s, iter);
1320         }
1321
1322         __print_graph_headers_flags(s, flags);
1323 }
1324
1325 void graph_trace_open(struct trace_iterator *iter)
1326 {
1327         /* pid and depth on the last trace processed */
1328         struct fgraph_data *data;
1329         int cpu;
1330
1331         iter->private = NULL;
1332
1333         data = kzalloc(sizeof(*data), GFP_KERNEL);
1334         if (!data)
1335                 goto out_err;
1336
1337         data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
1338         if (!data->cpu_data)
1339                 goto out_err_free;
1340
1341         for_each_possible_cpu(cpu) {
1342                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1343                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1344                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1345                 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1346
1347                 *pid = -1;
1348                 *depth = 0;
1349                 *ignore = 0;
1350                 *depth_irq = -1;
1351         }
1352
1353         iter->private = data;
1354
1355         return;
1356
1357  out_err_free:
1358         kfree(data);
1359  out_err:
1360         pr_warning("function graph tracer: not enough memory\n");
1361 }
1362
1363 void graph_trace_close(struct trace_iterator *iter)
1364 {
1365         struct fgraph_data *data = iter->private;
1366
1367         if (data) {
1368                 free_percpu(data->cpu_data);
1369                 kfree(data);
1370         }
1371 }
1372
1373 static int
1374 func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1375 {
1376         if (bit == TRACE_GRAPH_PRINT_IRQS)
1377                 ftrace_graph_skip_irqs = !set;
1378
1379         return 0;
1380 }
1381
1382 static struct trace_event_functions graph_functions = {
1383         .trace          = print_graph_function_event,
1384 };
1385
1386 static struct trace_event graph_trace_entry_event = {
1387         .type           = TRACE_GRAPH_ENT,
1388         .funcs          = &graph_functions,
1389 };
1390
1391 static struct trace_event graph_trace_ret_event = {
1392         .type           = TRACE_GRAPH_RET,
1393         .funcs          = &graph_functions
1394 };
1395
1396 static struct tracer graph_trace __tracer_data = {
1397         .name           = "function_graph",
1398         .update_thresh  = graph_trace_update_thresh,
1399         .open           = graph_trace_open,
1400         .pipe_open      = graph_trace_open,
1401         .close          = graph_trace_close,
1402         .pipe_close     = graph_trace_close,
1403         .init           = graph_trace_init,
1404         .reset          = graph_trace_reset,
1405         .print_line     = print_graph_function,
1406         .print_header   = print_graph_headers,
1407         .flags          = &tracer_flags,
1408         .set_flag       = func_graph_set_flag,
1409 #ifdef CONFIG_FTRACE_SELFTEST
1410         .selftest       = trace_selftest_startup_function_graph,
1411 #endif
1412 };
1413
1414
1415 static ssize_t
1416 graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1417                   loff_t *ppos)
1418 {
1419         unsigned long val;
1420         int ret;
1421
1422         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1423         if (ret)
1424                 return ret;
1425
1426         max_depth = val;
1427
1428         *ppos += cnt;
1429
1430         return cnt;
1431 }
1432
1433 static ssize_t
1434 graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1435                  loff_t *ppos)
1436 {
1437         char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1438         int n;
1439
1440         n = sprintf(buf, "%d\n", max_depth);
1441
1442         return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1443 }
1444
1445 static const struct file_operations graph_depth_fops = {
1446         .open           = tracing_open_generic,
1447         .write          = graph_depth_write,
1448         .read           = graph_depth_read,
1449         .llseek         = generic_file_llseek,
1450 };
1451
1452 static __init int init_graph_debugfs(void)
1453 {
1454         struct dentry *d_tracer;
1455
1456         d_tracer = tracing_init_dentry();
1457         if (!d_tracer)
1458                 return 0;
1459
1460         trace_create_file("max_graph_depth", 0644, d_tracer,
1461                           NULL, &graph_depth_fops);
1462
1463         return 0;
1464 }
1465 fs_initcall(init_graph_debugfs);
1466
1467 static __init int init_graph_trace(void)
1468 {
1469         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1470
1471         if (!register_ftrace_event(&graph_trace_entry_event)) {
1472                 pr_warning("Warning: could not register graph trace events\n");
1473                 return 1;
1474         }
1475
1476         if (!register_ftrace_event(&graph_trace_ret_event)) {
1477                 pr_warning("Warning: could not register graph trace events\n");
1478                 return 1;
1479         }
1480
1481         return register_tracer(&graph_trace);
1482 }
1483
1484 core_initcall(init_graph_trace);