kernel/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/uaccess.h>
  10 #include <linux/ftrace.h>
  11 #include <linux/slab.h>
  12 #include <linux/fs.h>
  13
  14 #include "trace.h"
  15 #include "trace_output.h"
  16
  17 static bool kill_ftrace_graph;
  18
  19 /**
  20  * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
  21  *
  22  * ftrace_graph_stop() is called when a severe error is detected in
  23  * the function graph tracing. This function is called by the critical
  24  * paths of function graph to keep those paths from doing any more harm.
  25  */
  26 bool ftrace_graph_is_dead(void)
  27 {
  28         return kill_ftrace_graph;
  29 }
  30
  31 /**
  32  * ftrace_graph_stop - set to permanently disable function graph tracincg
  33  *
  34  * In case of an error int function graph tracing, this is called
  35  * to try to keep function graph tracing from causing any more harm.
  36  * Usually this is pretty severe and this is called to try to at least
  37  * get a warning out to the user.
  38  */
  39 void ftrace_graph_stop(void)
  40 {
  41         kill_ftrace_graph = true;
  42 }
  43
  44 /* When set, irq functions will be ignored */
  45 static int ftrace_graph_skip_irqs;
  46
  47 struct fgraph_cpu_data {
  48         pid_t           last_pid;
  49         int             depth;
  50         int             depth_irq;
  51         int             ignore;
  52         unsigned long   enter_funcs[FTRACE_RETFUNC_DEPTH];
  53 };
  54
  55 struct fgraph_data {
  56         struct fgraph_cpu_data __percpu *cpu_data;
  57
  58         /* Place to preserve last processed entry. */
  59         struct ftrace_graph_ent_entry   ent;
  60         struct ftrace_graph_ret_entry   ret;
  61         int                             failed;
  62         int                             cpu;
  63 };
  64
  65 #define TRACE_GRAPH_INDENT      2
  66
  67 static unsigned int max_depth;
  68
  69 static struct tracer_opt trace_opts[] = {
  70         /* Display overruns? (for self-debug purpose) */
  71         { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
  72         /* Display CPU ? */
  73         { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
  74         /* Display Overhead ? */
  75         { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
  76         /* Display proc name/pid */
  77         { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
  78         /* Display duration of execution */
  79         { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
  80         /* Display absolute time of an entry */
  81         { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
  82         /* Display interrupts */
  83         { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
  84         /* Display function name after trailing } */
  85         { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
  86         { } /* Empty entry */
  87 };
  88
  89 static struct tracer_flags tracer_flags = {
  90         /* Don't display overruns, proc, or tail by default */
  91         .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
  92                TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS,
  93         .opts = trace_opts
  94 };
  95
  96 static struct trace_array *graph_array;
  97
  98 /*
  99  * DURATION column is being also used to display IRQ signs,
 100  * following values are used by print_graph_irq and others
 101  * to fill in space into DURATION column.
 102  */
 103 enum {
 104         FLAGS_FILL_FULL  = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 105         FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 106         FLAGS_FILL_END   = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 107 };
 108
 109 static void
 110 print_graph_duration(unsigned long long duration, struct trace_seq *s,
 111                      u32 flags);
 112
 113 /* Add a function return address to the trace stack on thread info.*/
 114 int
 115 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 116                          unsigned long frame_pointer)
 117 {
 118         unsigned long long calltime;
 119         int index;
 120
 121         if (unlikely(ftrace_graph_is_dead()))
 122                 return -EBUSY;
 123
 124         if (!current->ret_stack)
 125                 return -EBUSY;
 126
 127         /*
 128          * We must make sure the ret_stack is tested before we read
 129          * anything else.
 130          */
 131         smp_rmb();
 132
 133         /* The return trace stack is full */
 134         if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
 135                 atomic_inc(&current->trace_overrun);
 136                 return -EBUSY;
 137         }
 138
 139         /*
 140          * The curr_ret_stack is an index to ftrace return stack of
 141          * current task.  Its value should be in [0, FTRACE_RETFUNC_
 142          * DEPTH) when the function graph tracer is used.  To support
 143          * filtering out specific functions, it makes the index
 144          * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
 145          * so when it sees a negative index the ftrace will ignore
 146          * the record.  And the index gets recovered when returning
 147          * from the filtered function by adding the FTRACE_NOTRACE_
 148          * DEPTH and then it'll continue to record functions normally.
 149          *
 150          * The curr_ret_stack is initialized to -1 and get increased
 151          * in this function.  So it can be less than -1 only if it was
 152          * filtered out via ftrace_graph_notrace_addr() which can be
 153          * set from set_graph_notrace file in tracefs by user.
 154          */
 155         if (current->curr_ret_stack < -1)
 156                 return -EBUSY;
 157
 158         calltime = trace_clock_local();
 159
 160         index = ++current->curr_ret_stack;
 161         if (ftrace_graph_notrace_addr(func))
 162                 current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
 163         barrier();
 164         current->ret_stack[index].ret = ret;
 165         current->ret_stack[index].func = func;
 166         current->ret_stack[index].calltime = calltime;
 167         current->ret_stack[index].subtime = 0;
 168         current->ret_stack[index].fp = frame_pointer;
 169         *depth = current->curr_ret_stack;
 170
 171         return 0;
 172 }
 173
 174 /* Retrieve a function return address to the trace stack on thread info.*/
 175 static void
 176 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
 177                         unsigned long frame_pointer)
 178 {
 179         int index;
 180
 181         index = current->curr_ret_stack;
 182
 183         /*
 184          * A negative index here means that it's just returned from a
 185          * notrace'd function.  Recover index to get an original
 186          * return address.  See ftrace_push_return_trace().
 187          *
 188          * TODO: Need to check whether the stack gets corrupted.
 189          */
 190         if (index < 0)
 191                 index += FTRACE_NOTRACE_DEPTH;
 192
 193         if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
 194                 ftrace_graph_stop();
 195                 WARN_ON(1);
 196                 /* Might as well panic, otherwise we have no where to go */
 197                 *ret = (unsigned long)panic;
 198                 return;
 199         }
 200
 201 #if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY)
 202         /*
 203          * The arch may choose to record the frame pointer used
 204          * and check it here to make sure that it is what we expect it
 205          * to be. If gcc does not set the place holder of the return
 206          * address in the frame pointer, and does a copy instead, then
 207          * the function graph trace will fail. This test detects this
 208          * case.
 209          *
 210          * Currently, x86_32 with optimize for size (-Os) makes the latest
 211          * gcc do the above.
 212          *
 213          * Note, -mfentry does not use frame pointers, and this test
 214          *  is not needed if CC_USING_FENTRY is set.
 215          */
 216         if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
 217                 ftrace_graph_stop();
 218                 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
 219                      "  from func %ps return to %lx\n",
 220                      current->ret_stack[index].fp,
 221                      frame_pointer,
 222                      (void *)current->ret_stack[index].func,
 223                      current->ret_stack[index].ret);
 224                 *ret = (unsigned long)panic;
 225                 return;
 226         }
 227 #endif
 228
 229         *ret = current->ret_stack[index].ret;
 230         trace->func = current->ret_stack[index].func;
 231         trace->calltime = current->ret_stack[index].calltime;
 232         trace->overrun = atomic_read(&current->trace_overrun);
 233         trace->depth = index;
 234 }
 235
 236 /*
 237  * Send the trace to the ring-buffer.
 238  * @return the original return address.
 239  */
 240 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 241 {
 242         struct ftrace_graph_ret trace;
 243         unsigned long ret;
 244
 245         ftrace_pop_return_trace(&trace, &ret, frame_pointer);
 246         trace.rettime = trace_clock_local();
 247         barrier();
 248         current->curr_ret_stack--;
 249         /*
 250          * The curr_ret_stack can be less than -1 only if it was
 251          * filtered out and it's about to return from the function.
 252          * Recover the index and continue to trace normal functions.
 253          */
 254         if (current->curr_ret_stack < -1) {
 255                 current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
 256                 return ret;
 257         }
 258
 259         /*
 260          * The trace should run after decrementing the ret counter
 261          * in case an interrupt were to come in. We don't want to
 262          * lose the interrupt if max_depth is set.
 263          */
 264         ftrace_graph_return(&trace);
 265
 266         if (unlikely(!ret)) {
 267                 ftrace_graph_stop();
 268                 WARN_ON(1);
 269                 /* Might as well panic. What else to do? */
 270                 ret = (unsigned long)panic;
 271         }
 272
 273         return ret;
 274 }
 275
 276 int __trace_graph_entry(struct trace_array *tr,
 277                                 struct ftrace_graph_ent *trace,
 278                                 unsigned long flags,
 279                                 int pc)
 280 {
 281         struct ftrace_event_call *call = &event_funcgraph_entry;
 282         struct ring_buffer_event *event;
 283         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 284         struct ftrace_graph_ent_entry *entry;
 285
 286         if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
 287                 return 0;
 288
 289         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
 290                                           sizeof(*entry), flags, pc);
 291         if (!event)
 292                 return 0;
 293         entry   = ring_buffer_event_data(event);
 294         entry->graph_ent                        = *trace;
 295         if (!call_filter_check_discard(call, entry, buffer, event))
 296                 __buffer_unlock_commit(buffer, event);
 297
 298         return 1;
 299 }
 300
 301 static inline int ftrace_graph_ignore_irqs(void)
 302 {
 303         if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
 304                 return 0;
 305
 306         return in_irq();
 307 }
 308
 309 int trace_graph_entry(struct ftrace_graph_ent *trace)
 310 {
 311         struct trace_array *tr = graph_array;
 312         struct trace_array_cpu *data;
 313         unsigned long flags;
 314         long disabled;
 315         int ret;
 316         int cpu;
 317         int pc;
 318
 319         if (!ftrace_trace_task(current))
 320                 return 0;
 321
 322         /* trace it when it is-nested-in or is a function enabled. */
 323         if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
 324              ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
 325             (max_depth && trace->depth >= max_depth))
 326                 return 0;
 327
 328         /*
 329          * Do not trace a function if it's filtered by set_graph_notrace.
 330          * Make the index of ret stack negative to indicate that it should
 331          * ignore further functions.  But it needs its own ret stack entry
 332          * to recover the original index in order to continue tracing after
 333          * returning from the function.
 334          */
 335         if (ftrace_graph_notrace_addr(trace->func))
 336                 return 1;
 337
 338         local_irq_save(flags);
 339         cpu = raw_smp_processor_id();
 340         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 341         disabled = atomic_inc_return(&data->disabled);
 342         if (likely(disabled == 1)) {
 343                 pc = preempt_count();
 344                 ret = __trace_graph_entry(tr, trace, flags, pc);
 345         } else {
 346                 ret = 0;
 347         }
 348
 349         atomic_dec(&data->disabled);
 350         local_irq_restore(flags);
 351
 352         return ret;
 353 }
 354
 355 static int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
 356 {
 357         if (tracing_thresh)
 358                 return 1;
 359         else
 360                 return trace_graph_entry(trace);
 361 }
 362
 363 static void
 364 __trace_graph_function(struct trace_array *tr,
 365                 unsigned long ip, unsigned long flags, int pc)
 366 {
 367         u64 time = trace_clock_local();
 368         struct ftrace_graph_ent ent = {
 369                 .func  = ip,
 370                 .depth = 0,
 371         };
 372         struct ftrace_graph_ret ret = {
 373                 .func     = ip,
 374                 .depth    = 0,
 375                 .calltime = time,
 376                 .rettime  = time,
 377         };
 378
 379         __trace_graph_entry(tr, &ent, flags, pc);
 380         __trace_graph_return(tr, &ret, flags, pc);
 381 }
 382
 383 void
 384 trace_graph_function(struct trace_array *tr,
 385                 unsigned long ip, unsigned long parent_ip,
 386                 unsigned long flags, int pc)
 387 {
 388         __trace_graph_function(tr, ip, flags, pc);
 389 }
 390
 391 void __trace_graph_return(struct trace_array *tr,
 392                                 struct ftrace_graph_ret *trace,
 393                                 unsigned long flags,
 394                                 int pc)
 395 {
 396         struct ftrace_event_call *call = &event_funcgraph_exit;
 397         struct ring_buffer_event *event;
 398         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 399         struct ftrace_graph_ret_entry *entry;
 400
 401         if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
 402                 return;
 403
 404         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
 405                                           sizeof(*entry), flags, pc);
 406         if (!event)
 407                 return;
 408         entry   = ring_buffer_event_data(event);
 409         entry->ret                              = *trace;
 410         if (!call_filter_check_discard(call, entry, buffer, event))
 411                 __buffer_unlock_commit(buffer, event);
 412 }
 413
 414 void trace_graph_return(struct ftrace_graph_ret *trace)
 415 {
 416         struct trace_array *tr = graph_array;
 417         struct trace_array_cpu *data;
 418         unsigned long flags;
 419         long disabled;
 420         int cpu;
 421         int pc;
 422
 423         local_irq_save(flags);
 424         cpu = raw_smp_processor_id();
 425         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 426         disabled = atomic_inc_return(&data->disabled);
 427         if (likely(disabled == 1)) {
 428                 pc = preempt_count();
 429                 __trace_graph_return(tr, trace, flags, pc);
 430         }
 431         atomic_dec(&data->disabled);
 432         local_irq_restore(flags);
 433 }
 434
 435 void set_graph_array(struct trace_array *tr)
 436 {
 437         graph_array = tr;
 438
 439         /* Make graph_array visible before we start tracing */
 440
 441         smp_mb();
 442 }
 443
 444 static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 445 {
 446         if (tracing_thresh &&
 447             (trace->rettime - trace->calltime < tracing_thresh))
 448                 return;
 449         else
 450                 trace_graph_return(trace);
 451 }
 452
 453 static int graph_trace_init(struct trace_array *tr)
 454 {
 455         int ret;
 456
 457         set_graph_array(tr);
 458         if (tracing_thresh)
 459                 ret = register_ftrace_graph(&trace_graph_thresh_return,
 460                                             &trace_graph_thresh_entry);
 461         else
 462                 ret = register_ftrace_graph(&trace_graph_return,
 463                                             &trace_graph_entry);
 464         if (ret)
 465                 return ret;
 466         tracing_start_cmdline_record();
 467
 468         return 0;
 469 }
 470
 471 static void graph_trace_reset(struct trace_array *tr)
 472 {
 473         tracing_stop_cmdline_record();
 474         unregister_ftrace_graph();
 475 }
 476
 477 static int graph_trace_update_thresh(struct trace_array *tr)
 478 {
 479         graph_trace_reset(tr);
 480         return graph_trace_init(tr);
 481 }
 482
 483 static int max_bytes_for_cpu;
 484
 485 static void print_graph_cpu(struct trace_seq *s, int cpu)
 486 {
 487         /*
 488          * Start with a space character - to make it stand out
 489          * to the right a bit when trace output is pasted into
 490          * email:
 491          */
 492         trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 493 }
 494
 495 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 496
 497 static void print_graph_proc(struct trace_seq *s, pid_t pid)
 498 {
 499         char comm[TASK_COMM_LEN];
 500         /* sign + log10(MAX_INT) + '\0' */
 501         char pid_str[11];
 502         int spaces = 0;
 503         int len;
 504         int i;
 505
 506         trace_find_cmdline(pid, comm);
 507         comm[7] = '\0';
 508         sprintf(pid_str, "%d", pid);
 509
 510         /* 1 stands for the "-" character */
 511         len = strlen(comm) + strlen(pid_str) + 1;
 512
 513         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 514                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 515
 516         /* First spaces to align center */
 517         for (i = 0; i < spaces / 2; i++)
 518                 trace_seq_putc(s, ' ');
 519
 520         trace_seq_printf(s, "%s-%s", comm, pid_str);
 521
 522         /* Last spaces to align center */
 523         for (i = 0; i < spaces - (spaces / 2); i++)
 524                 trace_seq_putc(s, ' ');
 525 }
 526
 527
 528 static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 529 {
 530         trace_seq_putc(s, ' ');
 531         trace_print_lat_fmt(s, entry);
 532 }
 533
 534 /* If the pid changed since the last trace, output this event */
 535 static void
 536 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 537 {
 538         pid_t prev_pid;
 539         pid_t *last_pid;
 540
 541         if (!data)
 542                 return;
 543
 544         last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
 545
 546         if (*last_pid == pid)
 547                 return;
 548
 549         prev_pid = *last_pid;
 550         *last_pid = pid;
 551
 552         if (prev_pid == -1)
 553                 return;
 554 /*
 555  * Context-switch trace line:
 556
 557  ------------------------------------------
 558  | 1)  migration/0--1  =>  sshd-1755
 559  ------------------------------------------
 560
 561  */
 562         trace_seq_puts(s, " ------------------------------------------\n");
 563         print_graph_cpu(s, cpu);
 564         print_graph_proc(s, prev_pid);
 565         trace_seq_puts(s, " => ");
 566         print_graph_proc(s, pid);
 567         trace_seq_puts(s, "\n ------------------------------------------\n\n");
 568 }
 569
 570 static struct ftrace_graph_ret_entry *
 571 get_return_for_leaf(struct trace_iterator *iter,
 572                 struct ftrace_graph_ent_entry *curr)
 573 {
 574         struct fgraph_data *data = iter->private;
 575         struct ring_buffer_iter *ring_iter = NULL;
 576         struct ring_buffer_event *event;
 577         struct ftrace_graph_ret_entry *next;
 578
 579         /*
 580          * If the previous output failed to write to the seq buffer,
 581          * then we just reuse the data from before.
 582          */
 583         if (data && data->failed) {
 584                 curr = &data->ent;
 585                 next = &data->ret;
 586         } else {
 587
 588                 ring_iter = trace_buffer_iter(iter, iter->cpu);
 589
 590                 /* First peek to compare current entry and the next one */
 591                 if (ring_iter)
 592                         event = ring_buffer_iter_peek(ring_iter, NULL);
 593                 else {
 594                         /*
 595                          * We need to consume the current entry to see
 596                          * the next one.
 597                          */
 598                         ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
 599                                             NULL, NULL);
 600                         event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
 601                                                  NULL, NULL);
 602                 }
 603
 604                 if (!event)
 605                         return NULL;
 606
 607                 next = ring_buffer_event_data(event);
 608
 609                 if (data) {
 610                         /*
 611                          * Save current and next entries for later reference
 612                          * if the output fails.
 613                          */
 614                         data->ent = *curr;
 615                         /*
 616                          * If the next event is not a return type, then
 617                          * we only care about what type it is. Otherwise we can
 618                          * safely copy the entire event.
 619                          */
 620                         if (next->ent.type == TRACE_GRAPH_RET)
 621                                 data->ret = *next;
 622                         else
 623                                 data->ret.ent.type = next->ent.type;
 624                 }
 625         }
 626
 627         if (next->ent.type != TRACE_GRAPH_RET)
 628                 return NULL;
 629
 630         if (curr->ent.pid != next->ent.pid ||
 631                         curr->graph_ent.func != next->ret.func)
 632                 return NULL;
 633
 634         /* this is a leaf, now advance the iterator */
 635         if (ring_iter)
 636                 ring_buffer_read(ring_iter, NULL);
 637
 638         return next;
 639 }
 640
 641 static void print_graph_abs_time(u64 t, struct trace_seq *s)
 642 {
 643         unsigned long usecs_rem;
 644
 645         usecs_rem = do_div(t, NSEC_PER_SEC);
 646         usecs_rem /= 1000;
 647
 648         trace_seq_printf(s, "%5lu.%06lu |  ",
 649                          (unsigned long)t, usecs_rem);
 650 }
 651
 652 static void
 653 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 654                 enum trace_type type, int cpu, pid_t pid, u32 flags)
 655 {
 656         struct trace_seq *s = &iter->seq;
 657         struct trace_entry *ent = iter->ent;
 658
 659         if (addr < (unsigned long)__irqentry_text_start ||
 660                 addr >= (unsigned long)__irqentry_text_end)
 661                 return;
 662
 663         if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
 664                 /* Absolute time */
 665                 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 666                         print_graph_abs_time(iter->ts, s);
 667
 668                 /* Cpu */
 669                 if (flags & TRACE_GRAPH_PRINT_CPU)
 670                         print_graph_cpu(s, cpu);
 671
 672                 /* Proc */
 673                 if (flags & TRACE_GRAPH_PRINT_PROC) {
 674                         print_graph_proc(s, pid);
 675                         trace_seq_puts(s, " | ");
 676                 }
 677
 678                 /* Latency format */
 679                 if (trace_flags & TRACE_ITER_LATENCY_FMT)
 680                         print_graph_lat_fmt(s, ent);
 681         }
 682
 683         /* No overhead */
 684         print_graph_duration(0, s, flags | FLAGS_FILL_START);
 685
 686         if (type == TRACE_GRAPH_ENT)
 687                 trace_seq_puts(s, "==========>");
 688         else
 689                 trace_seq_puts(s, "<==========");
 690
 691         print_graph_duration(0, s, flags | FLAGS_FILL_END);
 692         trace_seq_putc(s, '\n');
 693 }
 694
 695 void
 696 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 697 {
 698         unsigned long nsecs_rem = do_div(duration, 1000);
 699         /* log10(ULONG_MAX) + '\0' */
 700         char usecs_str[21];
 701         char nsecs_str[5];
 702         int len;
 703         int i;
 704
 705         sprintf(usecs_str, "%lu", (unsigned long) duration);
 706
 707         /* Print msecs */
 708         trace_seq_printf(s, "%s", usecs_str);
 709
 710         len = strlen(usecs_str);
 711
 712         /* Print nsecs (we don't want to exceed 7 numbers) */
 713         if (len < 7) {
 714                 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
 715
 716                 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
 717                 trace_seq_printf(s, ".%s", nsecs_str);
 718                 len += strlen(nsecs_str);
 719         }
 720
 721         trace_seq_puts(s, " us ");
 722
 723         /* Print remaining spaces to fit the row's width */
 724         for (i = len; i < 7; i++)
 725                 trace_seq_putc(s, ' ');
 726 }
 727
 728 static void
 729 print_graph_duration(unsigned long long duration, struct trace_seq *s,
 730                      u32 flags)
 731 {
 732         if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
 733             !(trace_flags & TRACE_ITER_CONTEXT_INFO))
 734                 return;
 735
 736         /* No real adata, just filling the column with spaces */
 737         switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
 738         case FLAGS_FILL_FULL:
 739                 trace_seq_puts(s, "              |  ");
 740                 return;
 741         case FLAGS_FILL_START:
 742                 trace_seq_puts(s, "  ");
 743                 return;
 744         case FLAGS_FILL_END:
 745                 trace_seq_puts(s, " |");
 746                 return;
 747         }
 748
 749         /* Signal a overhead of time execution to the output */
 750         if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
 751                 trace_seq_printf(s, "%c ", trace_find_mark(duration));
 752         else
 753                 trace_seq_puts(s, "  ");
 754
 755         trace_print_graph_duration(duration, s);
 756         trace_seq_puts(s, "|  ");
 757 }
 758
 759 /* Case of a leaf function on its call entry */
 760 static enum print_line_t
 761 print_graph_entry_leaf(struct trace_iterator *iter,
 762                 struct ftrace_graph_ent_entry *entry,
 763                 struct ftrace_graph_ret_entry *ret_entry,
 764                 struct trace_seq *s, u32 flags)
 765 {
 766         struct fgraph_data *data = iter->private;
 767         struct ftrace_graph_ret *graph_ret;
 768         struct ftrace_graph_ent *call;
 769         unsigned long long duration;
 770         int i;
 771
 772         graph_ret = &ret_entry->ret;
 773         call = &entry->graph_ent;
 774         duration = graph_ret->rettime - graph_ret->calltime;
 775
 776         if (data) {
 777                 struct fgraph_cpu_data *cpu_data;
 778                 int cpu = iter->cpu;
 779
 780                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 781
 782                 /*
 783                  * Comments display at + 1 to depth. Since
 784                  * this is a leaf function, keep the comments
 785                  * equal to this depth.
 786                  */
 787                 cpu_data->depth = call->depth - 1;
 788
 789                 /* No need to keep this function around for this depth */
 790                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 791                         cpu_data->enter_funcs[call->depth] = 0;
 792         }
 793
 794         /* Overhead and duration */
 795         print_graph_duration(duration, s, flags);
 796
 797         /* Function */
 798         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
 799                 trace_seq_putc(s, ' ');
 800
 801         trace_seq_printf(s, "%ps();\n", (void *)call->func);
 802
 803         return trace_handle_return(s);
 804 }
 805
 806 static enum print_line_t
 807 print_graph_entry_nested(struct trace_iterator *iter,
 808                          struct ftrace_graph_ent_entry *entry,
 809                          struct trace_seq *s, int cpu, u32 flags)
 810 {
 811         struct ftrace_graph_ent *call = &entry->graph_ent;
 812         struct fgraph_data *data = iter->private;
 813         int i;
 814
 815         if (data) {
 816                 struct fgraph_cpu_data *cpu_data;
 817                 int cpu = iter->cpu;
 818
 819                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 820                 cpu_data->depth = call->depth;
 821
 822                 /* Save this function pointer to see if the exit matches */
 823                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 824                         cpu_data->enter_funcs[call->depth] = call->func;
 825         }
 826
 827         /* No time */
 828         print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
 829
 830         /* Function */
 831         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
 832                 trace_seq_putc(s, ' ');
 833
 834         trace_seq_printf(s, "%ps() {\n", (void *)call->func);
 835
 836         if (trace_seq_has_overflowed(s))
 837                 return TRACE_TYPE_PARTIAL_LINE;
 838
 839         /*
 840          * we already consumed the current entry to check the next one
 841          * and see if this is a leaf.
 842          */
 843         return TRACE_TYPE_NO_CONSUME;
 844 }
 845
 846 static void
 847 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 848                      int type, unsigned long addr, u32 flags)
 849 {
 850         struct fgraph_data *data = iter->private;
 851         struct trace_entry *ent = iter->ent;
 852         int cpu = iter->cpu;
 853
 854         /* Pid */
 855         verif_pid(s, ent->pid, cpu, data);
 856
 857         if (type)
 858                 /* Interrupt */
 859                 print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
 860
 861         if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
 862                 return;
 863
 864         /* Absolute time */
 865         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 866                 print_graph_abs_time(iter->ts, s);
 867
 868         /* Cpu */
 869         if (flags & TRACE_GRAPH_PRINT_CPU)
 870                 print_graph_cpu(s, cpu);
 871
 872         /* Proc */
 873         if (flags & TRACE_GRAPH_PRINT_PROC) {
 874                 print_graph_proc(s, ent->pid);
 875                 trace_seq_puts(s, " | ");
 876         }
 877
 878         /* Latency format */
 879         if (trace_flags & TRACE_ITER_LATENCY_FMT)
 880                 print_graph_lat_fmt(s, ent);
 881
 882         return;
 883 }
 884
 885 /*
 886  * Entry check for irq code
 887  *
 888  * returns 1 if
 889  *  - we are inside irq code
 890  *  - we just entered irq code
 891  *
 892  * retunns 0 if
 893  *  - funcgraph-interrupts option is set
 894  *  - we are not inside irq code
 895  */
 896 static int
 897 check_irq_entry(struct trace_iterator *iter, u32 flags,
 898                 unsigned long addr, int depth)
 899 {
 900         int cpu = iter->cpu;
 901         int *depth_irq;
 902         struct fgraph_data *data = iter->private;
 903
 904         /*
 905          * If we are either displaying irqs, or we got called as
 906          * a graph event and private data does not exist,
 907          * then we bypass the irq check.
 908          */
 909         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
 910             (!data))
 911                 return 0;
 912
 913         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 914
 915         /*
 916          * We are inside the irq code
 917          */
 918         if (*depth_irq >= 0)
 919                 return 1;
 920
 921         if ((addr < (unsigned long)__irqentry_text_start) ||
 922             (addr >= (unsigned long)__irqentry_text_end))
 923                 return 0;
 924
 925         /*
 926          * We are entering irq code.
 927          */
 928         *depth_irq = depth;
 929         return 1;
 930 }
 931
 932 /*
 933  * Return check for irq code
 934  *
 935  * returns 1 if
 936  *  - we are inside irq code
 937  *  - we just left irq code
 938  *
 939  * returns 0 if
 940  *  - funcgraph-interrupts option is set
 941  *  - we are not inside irq code
 942  */
 943 static int
 944 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
 945 {
 946         int cpu = iter->cpu;
 947         int *depth_irq;
 948         struct fgraph_data *data = iter->private;
 949
 950         /*
 951          * If we are either displaying irqs, or we got called as
 952          * a graph event and private data does not exist,
 953          * then we bypass the irq check.
 954          */
 955         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
 956             (!data))
 957                 return 0;
 958
 959         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 960
 961         /*
 962          * We are not inside the irq code.
 963          */
 964         if (*depth_irq == -1)
 965                 return 0;
 966
 967         /*
 968          * We are inside the irq code, and this is returning entry.
 969          * Let's not trace it and clear the entry depth, since
 970          * we are out of irq code.
 971          *
 972          * This condition ensures that we 'leave the irq code' once
 973          * we are out of the entry depth. Thus protecting us from
 974          * the RETURN entry loss.
 975          */
 976         if (*depth_irq >= depth) {
 977                 *depth_irq = -1;
 978                 return 1;
 979         }
 980
 981         /*
 982          * We are inside the irq code, and this is not the entry.
 983          */
 984         return 1;
 985 }
 986
 987 static enum print_line_t
 988 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 989                         struct trace_iterator *iter, u32 flags)
 990 {
 991         struct fgraph_data *data = iter->private;
 992         struct ftrace_graph_ent *call = &field->graph_ent;
 993         struct ftrace_graph_ret_entry *leaf_ret;
 994         static enum print_line_t ret;
 995         int cpu = iter->cpu;
 996
 997         if (check_irq_entry(iter, flags, call->func, call->depth))
 998                 return TRACE_TYPE_HANDLED;
 999
1000         print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
1001
1002         leaf_ret = get_return_for_leaf(iter, field);
1003         if (leaf_ret)
1004                 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1005         else
1006                 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1007
1008         if (data) {
1009                 /*
1010                  * If we failed to write our output, then we need to make
1011                  * note of it. Because we already consumed our entry.
1012                  */
1013                 if (s->full) {
1014                         data->failed = 1;
1015                         data->cpu = cpu;
1016                 } else
1017                         data->failed = 0;
1018         }
1019
1020         return ret;
1021 }
1022
1023 static enum print_line_t
1024 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1025                    struct trace_entry *ent, struct trace_iterator *iter,
1026                    u32 flags)
1027 {
1028         unsigned long long duration = trace->rettime - trace->calltime;
1029         struct fgraph_data *data = iter->private;
1030         pid_t pid = ent->pid;
1031         int cpu = iter->cpu;
1032         int func_match = 1;
1033         int i;
1034
1035         if (check_irq_return(iter, flags, trace->depth))
1036                 return TRACE_TYPE_HANDLED;
1037
1038         if (data) {
1039                 struct fgraph_cpu_data *cpu_data;
1040                 int cpu = iter->cpu;
1041
1042                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1043
1044                 /*
1045                  * Comments display at + 1 to depth. This is the
1046                  * return from a function, we now want the comments
1047                  * to display at the same level of the bracket.
1048                  */
1049                 cpu_data->depth = trace->depth - 1;
1050
1051                 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
1052                         if (cpu_data->enter_funcs[trace->depth] != trace->func)
1053                                 func_match = 0;
1054                         cpu_data->enter_funcs[trace->depth] = 0;
1055                 }
1056         }
1057
1058         print_graph_prologue(iter, s, 0, 0, flags);
1059
1060         /* Overhead and duration */
1061         print_graph_duration(duration, s, flags);
1062
1063         /* Closing brace */
1064         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
1065                 trace_seq_putc(s, ' ');
1066
1067         /*
1068          * If the return function does not have a matching entry,
1069          * then the entry was lost. Instead of just printing
1070          * the '}' and letting the user guess what function this
1071          * belongs to, write out the function name. Always do
1072          * that if the funcgraph-tail option is enabled.
1073          */
1074         if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
1075                 trace_seq_puts(s, "}\n");
1076         else
1077                 trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1078
1079         /* Overrun */
1080         if (flags & TRACE_GRAPH_PRINT_OVERRUN)
1081                 trace_seq_printf(s, " (Overruns: %lu)\n",
1082                                  trace->overrun);
1083
1084         print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1085                         cpu, pid, flags);
1086
1087         return trace_handle_return(s);
1088 }
1089
1090 static enum print_line_t
1091 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1092                     struct trace_iterator *iter, u32 flags)
1093 {
1094         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1095         struct fgraph_data *data = iter->private;
1096         struct trace_event *event;
1097         int depth = 0;
1098         int ret;
1099         int i;
1100
1101         if (data)
1102                 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1103
1104         print_graph_prologue(iter, s, 0, 0, flags);
1105
1106         /* No time */
1107         print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
1108
1109         /* Indentation */
1110         if (depth > 0)
1111                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
1112                         trace_seq_putc(s, ' ');
1113
1114         /* The comment */
1115         trace_seq_puts(s, "/* ");
1116
1117         switch (iter->ent->type) {
1118         case TRACE_BPRINT:
1119                 ret = trace_print_bprintk_msg_only(iter);
1120                 if (ret != TRACE_TYPE_HANDLED)
1121                         return ret;
1122                 break;
1123         case TRACE_PRINT:
1124                 ret = trace_print_printk_msg_only(iter);
1125                 if (ret != TRACE_TYPE_HANDLED)
1126                         return ret;
1127                 break;
1128         default:
1129                 event = ftrace_find_event(ent->type);
1130                 if (!event)
1131                         return TRACE_TYPE_UNHANDLED;
1132
1133                 ret = event->funcs->trace(iter, sym_flags, event);
1134                 if (ret != TRACE_TYPE_HANDLED)
1135                         return ret;
1136         }
1137
1138         if (trace_seq_has_overflowed(s))
1139                 goto out;
1140
1141         /* Strip ending newline */
1142         if (s->buffer[s->seq.len - 1] == '\n') {
1143                 s->buffer[s->seq.len - 1] = '\0';
1144                 s->seq.len--;
1145         }
1146
1147         trace_seq_puts(s, " */\n");
1148  out:
1149         return trace_handle_return(s);
1150 }
1151
1152
1153 enum print_line_t
1154 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1155 {
1156         struct ftrace_graph_ent_entry *field;
1157         struct fgraph_data *data = iter->private;
1158         struct trace_entry *entry = iter->ent;
1159         struct trace_seq *s = &iter->seq;
1160         int cpu = iter->cpu;
1161         int ret;
1162
1163         if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1164                 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1165                 return TRACE_TYPE_HANDLED;
1166         }
1167
1168         /*
1169          * If the last output failed, there's a possibility we need
1170          * to print out the missing entry which would never go out.
1171          */
1172         if (data && data->failed) {
1173                 field = &data->ent;
1174                 iter->cpu = data->cpu;
1175                 ret = print_graph_entry(field, s, iter, flags);
1176                 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1177                         per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1178                         ret = TRACE_TYPE_NO_CONSUME;
1179                 }
1180                 iter->cpu = cpu;
1181                 return ret;
1182         }
1183
1184         switch (entry->type) {
1185         case TRACE_GRAPH_ENT: {
1186                 /*
1187                  * print_graph_entry() may consume the current event,
1188                  * thus @field may become invalid, so we need to save it.
1189                  * sizeof(struct ftrace_graph_ent_entry) is very small,
1190                  * it can be safely saved at the stack.
1191                  */
1192                 struct ftrace_graph_ent_entry saved;
1193                 trace_assign_type(field, entry);
1194                 saved = *field;
1195                 return print_graph_entry(&saved, s, iter, flags);
1196         }
1197         case TRACE_GRAPH_RET: {
1198                 struct ftrace_graph_ret_entry *field;
1199                 trace_assign_type(field, entry);
1200                 return print_graph_return(&field->ret, s, entry, iter, flags);
1201         }
1202         case TRACE_STACK:
1203         case TRACE_FN:
1204                 /* dont trace stack and functions as comments */
1205                 return TRACE_TYPE_UNHANDLED;
1206
1207         default:
1208                 return print_graph_comment(s, entry, iter, flags);
1209         }
1210
1211         return TRACE_TYPE_HANDLED;
1212 }
1213
1214 static enum print_line_t
1215 print_graph_function(struct trace_iterator *iter)
1216 {
1217         return print_graph_function_flags(iter, tracer_flags.val);
1218 }
1219
1220 static enum print_line_t
1221 print_graph_function_event(struct trace_iterator *iter, int flags,
1222                            struct trace_event *event)
1223 {
1224         return print_graph_function(iter);
1225 }
1226
1227 static void print_lat_header(struct seq_file *s, u32 flags)
1228 {
1229         static const char spaces[] = "                " /* 16 spaces */
1230                 "    "                                  /* 4 spaces */
1231                 "                 ";                    /* 17 spaces */
1232         int size = 0;
1233
1234         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1235                 size += 16;
1236         if (flags & TRACE_GRAPH_PRINT_CPU)
1237                 size += 4;
1238         if (flags & TRACE_GRAPH_PRINT_PROC)
1239                 size += 17;
1240
1241         seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
1242         seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
1243         seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1244         seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
1245         seq_printf(s, "#%.*s||| /                      \n", size, spaces);
1246 }
1247
1248 static void __print_graph_headers_flags(struct seq_file *s, u32 flags)
1249 {
1250         int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1251
1252         if (lat)
1253                 print_lat_header(s, flags);
1254
1255         /* 1st line */
1256         seq_putc(s, '#');
1257         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1258                 seq_puts(s, "     TIME       ");
1259         if (flags & TRACE_GRAPH_PRINT_CPU)
1260                 seq_puts(s, " CPU");
1261         if (flags & TRACE_GRAPH_PRINT_PROC)
1262                 seq_puts(s, "  TASK/PID       ");
1263         if (lat)
1264                 seq_puts(s, "||||");
1265         if (flags & TRACE_GRAPH_PRINT_DURATION)
1266                 seq_puts(s, "  DURATION   ");
1267         seq_puts(s, "               FUNCTION CALLS\n");
1268
1269         /* 2nd line */
1270         seq_putc(s, '#');
1271         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1272                 seq_puts(s, "      |         ");
1273         if (flags & TRACE_GRAPH_PRINT_CPU)
1274                 seq_puts(s, " |  ");
1275         if (flags & TRACE_GRAPH_PRINT_PROC)
1276                 seq_puts(s, "   |    |        ");
1277         if (lat)
1278                 seq_puts(s, "||||");
1279         if (flags & TRACE_GRAPH_PRINT_DURATION)
1280                 seq_puts(s, "   |   |      ");
1281         seq_puts(s, "               |   |   |   |\n");
1282 }
1283
1284 static void print_graph_headers(struct seq_file *s)
1285 {
1286         print_graph_headers_flags(s, tracer_flags.val);
1287 }
1288
1289 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1290 {
1291         struct trace_iterator *iter = s->private;
1292
1293         if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
1294                 return;
1295
1296         if (trace_flags & TRACE_ITER_LATENCY_FMT) {
1297                 /* print nothing if the buffers are empty */
1298                 if (trace_empty(iter))
1299                         return;
1300
1301                 print_trace_header(s, iter);
1302         }
1303
1304         __print_graph_headers_flags(s, flags);
1305 }
1306
1307 void graph_trace_open(struct trace_iterator *iter)
1308 {
1309         /* pid and depth on the last trace processed */
1310         struct fgraph_data *data;
1311         gfp_t gfpflags;
1312         int cpu;
1313
1314         iter->private = NULL;
1315
1316         /* We can be called in atomic context via ftrace_dump() */
1317         gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
1318
1319         data = kzalloc(sizeof(*data), gfpflags);
1320         if (!data)
1321                 goto out_err;
1322
1323         data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
1324         if (!data->cpu_data)
1325                 goto out_err_free;
1326
1327         for_each_possible_cpu(cpu) {
1328                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1329                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1330                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1331                 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1332
1333                 *pid = -1;
1334                 *depth = 0;
1335                 *ignore = 0;
1336                 *depth_irq = -1;
1337         }
1338
1339         iter->private = data;
1340
1341         return;
1342
1343  out_err_free:
1344         kfree(data);
1345  out_err:
1346         pr_warning("function graph tracer: not enough memory\n");
1347 }
1348
1349 void graph_trace_close(struct trace_iterator *iter)
1350 {
1351         struct fgraph_data *data = iter->private;
1352
1353         if (data) {
1354                 free_percpu(data->cpu_data);
1355                 kfree(data);
1356         }
1357 }
1358
1359 static int
1360 func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1361 {
1362         if (bit == TRACE_GRAPH_PRINT_IRQS)
1363                 ftrace_graph_skip_irqs = !set;
1364
1365         return 0;
1366 }
1367
1368 static struct trace_event_functions graph_functions = {
1369         .trace          = print_graph_function_event,
1370 };
1371
1372 static struct trace_event graph_trace_entry_event = {
1373         .type           = TRACE_GRAPH_ENT,
1374         .funcs          = &graph_functions,
1375 };
1376
1377 static struct trace_event graph_trace_ret_event = {
1378         .type           = TRACE_GRAPH_RET,
1379         .funcs          = &graph_functions
1380 };
1381
1382 static struct tracer graph_trace __tracer_data = {
1383         .name           = "function_graph",
1384         .update_thresh  = graph_trace_update_thresh,
1385         .open           = graph_trace_open,
1386         .pipe_open      = graph_trace_open,
1387         .close          = graph_trace_close,
1388         .pipe_close     = graph_trace_close,
1389         .init           = graph_trace_init,
1390         .reset          = graph_trace_reset,
1391         .print_line     = print_graph_function,
1392         .print_header   = print_graph_headers,
1393         .flags          = &tracer_flags,
1394         .set_flag       = func_graph_set_flag,
1395 #ifdef CONFIG_FTRACE_SELFTEST
1396         .selftest       = trace_selftest_startup_function_graph,
1397 #endif
1398 };
1399
1400
1401 static ssize_t
1402 graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1403                   loff_t *ppos)
1404 {
1405         unsigned long val;
1406         int ret;
1407
1408         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1409         if (ret)
1410                 return ret;
1411
1412         max_depth = val;
1413
1414         *ppos += cnt;
1415
1416         return cnt;
1417 }
1418
1419 static ssize_t
1420 graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1421                  loff_t *ppos)
1422 {
1423         char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1424         int n;
1425
1426         n = sprintf(buf, "%d\n", max_depth);
1427
1428         return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1429 }
1430
1431 static const struct file_operations graph_depth_fops = {
1432         .open           = tracing_open_generic,
1433         .write          = graph_depth_write,
1434         .read           = graph_depth_read,
1435         .llseek         = generic_file_llseek,
1436 };
1437
1438 static __init int init_graph_tracefs(void)
1439 {
1440         struct dentry *d_tracer;
1441
1442         d_tracer = tracing_init_dentry();
1443         if (IS_ERR(d_tracer))
1444                 return 0;
1445
1446         trace_create_file("max_graph_depth", 0644, d_tracer,
1447                           NULL, &graph_depth_fops);
1448
1449         return 0;
1450 }
1451 fs_initcall(init_graph_tracefs);
1452
1453 static __init int init_graph_trace(void)
1454 {
1455         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1456
1457         if (!register_ftrace_event(&graph_trace_entry_event)) {
1458                 pr_warning("Warning: could not register graph trace events\n");
1459                 return 1;
1460         }
1461
1462         if (!register_ftrace_event(&graph_trace_ret_event)) {
1463                 pr_warning("Warning: could not register graph trace events\n");
1464                 return 1;
1465         }
1466
1467         return register_tracer(&graph_trace);
1468 }
1469
1470 core_initcall(init_graph_trace);