kernel/trace/trace_functions_graph.c

   1 /*
   2  *
   3  * Function graph tracer.
   4  * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
   5  * Mostly borrowed from function tracer which
   6  * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
   7  *
   8  */
   9 #include <linux/debugfs.h>
  10 #include <linux/uaccess.h>
  11 #include <linux/ftrace.h>
  12 #include <linux/slab.h>
  13 #include <linux/fs.h>
  14
  15 #include "trace.h"
  16 #include "trace_output.h"
  17
  18 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         if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
 734             !(trace_flags & TRACE_ITER_CONTEXT_INFO))
 735                 return;
 736
 737         /* No real adata, just filling the column with spaces */
 738         switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
 739         case FLAGS_FILL_FULL:
 740                 trace_seq_puts(s, "              |  ");
 741                 return;
 742         case FLAGS_FILL_START:
 743                 trace_seq_puts(s, "  ");
 744                 return;
 745         case FLAGS_FILL_END:
 746                 trace_seq_puts(s, " |");
 747                 return;
 748         }
 749
 750         /* Signal a overhead of time execution to the output */
 751         if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
 752                 trace_seq_printf(s, "%c ", trace_find_mark(duration));
 753         else
 754                 trace_seq_puts(s, "  ");
 755
 756         trace_print_graph_duration(duration, s);
 757         trace_seq_puts(s, "|  ");
 758 }
 759
 760 /* Case of a leaf function on its call entry */
 761 static enum print_line_t
 762 print_graph_entry_leaf(struct trace_iterator *iter,
 763                 struct ftrace_graph_ent_entry *entry,
 764                 struct ftrace_graph_ret_entry *ret_entry,
 765                 struct trace_seq *s, u32 flags)
 766 {
 767         struct fgraph_data *data = iter->private;
 768         struct ftrace_graph_ret *graph_ret;
 769         struct ftrace_graph_ent *call;
 770         unsigned long long duration;
 771         int i;
 772
 773         graph_ret = &ret_entry->ret;
 774         call = &entry->graph_ent;
 775         duration = graph_ret->rettime - graph_ret->calltime;
 776
 777         if (data) {
 778                 struct fgraph_cpu_data *cpu_data;
 779                 int cpu = iter->cpu;
 780
 781                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 782
 783                 /*
 784                  * Comments display at + 1 to depth. Since
 785                  * this is a leaf function, keep the comments
 786                  * equal to this depth.
 787                  */
 788                 cpu_data->depth = call->depth - 1;
 789
 790                 /* No need to keep this function around for this depth */
 791                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 792                         cpu_data->enter_funcs[call->depth] = 0;
 793         }
 794
 795         /* Overhead and duration */
 796         print_graph_duration(duration, s, flags);
 797
 798         /* Function */
 799         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
 800                 trace_seq_putc(s, ' ');
 801
 802         trace_seq_printf(s, "%ps();\n", (void *)call->func);
 803
 804         return trace_handle_return(s);
 805 }
 806
 807 static enum print_line_t
 808 print_graph_entry_nested(struct trace_iterator *iter,
 809                          struct ftrace_graph_ent_entry *entry,
 810                          struct trace_seq *s, int cpu, u32 flags)
 811 {
 812         struct ftrace_graph_ent *call = &entry->graph_ent;
 813         struct fgraph_data *data = iter->private;
 814         int i;
 815
 816         if (data) {
 817                 struct fgraph_cpu_data *cpu_data;
 818                 int cpu = iter->cpu;
 819
 820                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 821                 cpu_data->depth = call->depth;
 822
 823                 /* Save this function pointer to see if the exit matches */
 824                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 825                         cpu_data->enter_funcs[call->depth] = call->func;
 826         }
 827
 828         /* No time */
 829         print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
 830
 831         /* Function */
 832         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
 833                 trace_seq_putc(s, ' ');
 834
 835         trace_seq_printf(s, "%ps() {\n", (void *)call->func);
 836
 837         if (trace_seq_has_overflowed(s))
 838                 return TRACE_TYPE_PARTIAL_LINE;
 839
 840         /*
 841          * we already consumed the current entry to check the next one
 842          * and see if this is a leaf.
 843          */
 844         return TRACE_TYPE_NO_CONSUME;
 845 }
 846
 847 static void
 848 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 849                      int type, unsigned long addr, u32 flags)
 850 {
 851         struct fgraph_data *data = iter->private;
 852         struct trace_entry *ent = iter->ent;
 853         int cpu = iter->cpu;
 854
 855         /* Pid */
 856         verif_pid(s, ent->pid, cpu, data);
 857
 858         if (type)
 859                 /* Interrupt */
 860                 print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
 861
 862         if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
 863                 return;
 864
 865         /* Absolute time */
 866         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 867                 print_graph_abs_time(iter->ts, s);
 868
 869         /* Cpu */
 870         if (flags & TRACE_GRAPH_PRINT_CPU)
 871                 print_graph_cpu(s, cpu);
 872
 873         /* Proc */
 874         if (flags & TRACE_GRAPH_PRINT_PROC) {
 875                 print_graph_proc(s, ent->pid);
 876                 trace_seq_puts(s, " | ");
 877         }
 878
 879         /* Latency format */
 880         if (trace_flags & TRACE_ITER_LATENCY_FMT)
 881                 print_graph_lat_fmt(s, ent);
 882
 883         return;
 884 }
 885
 886 /*
 887  * Entry check for irq code
 888  *
 889  * returns 1 if
 890  *  - we are inside irq code
 891  *  - we just entered irq code
 892  *
 893  * retunns 0 if
 894  *  - funcgraph-interrupts option is set
 895  *  - we are not inside irq code
 896  */
 897 static int
 898 check_irq_entry(struct trace_iterator *iter, u32 flags,
 899                 unsigned long addr, int depth)
 900 {
 901         int cpu = iter->cpu;
 902         int *depth_irq;
 903         struct fgraph_data *data = iter->private;
 904
 905         /*
 906          * If we are either displaying irqs, or we got called as
 907          * a graph event and private data does not exist,
 908          * then we bypass the irq check.
 909          */
 910         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
 911             (!data))
 912                 return 0;
 913
 914         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 915
 916         /*
 917          * We are inside the irq code
 918          */
 919         if (*depth_irq >= 0)
 920                 return 1;
 921
 922         if ((addr < (unsigned long)__irqentry_text_start) ||
 923             (addr >= (unsigned long)__irqentry_text_end))
 924                 return 0;
 925
 926         /*
 927          * We are entering irq code.
 928          */
 929         *depth_irq = depth;
 930         return 1;
 931 }
 932
 933 /*
 934  * Return check for irq code
 935  *
 936  * returns 1 if
 937  *  - we are inside irq code
 938  *  - we just left irq code
 939  *
 940  * returns 0 if
 941  *  - funcgraph-interrupts option is set
 942  *  - we are not inside irq code
 943  */
 944 static int
 945 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
 946 {
 947         int cpu = iter->cpu;
 948         int *depth_irq;
 949         struct fgraph_data *data = iter->private;
 950
 951         /*
 952          * If we are either displaying irqs, or we got called as
 953          * a graph event and private data does not exist,
 954          * then we bypass the irq check.
 955          */
 956         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
 957             (!data))
 958                 return 0;
 959
 960         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 961
 962         /*
 963          * We are not inside the irq code.
 964          */
 965         if (*depth_irq == -1)
 966                 return 0;
 967
 968         /*
 969          * We are inside the irq code, and this is returning entry.
 970          * Let's not trace it and clear the entry depth, since
 971          * we are out of irq code.
 972          *
 973          * This condition ensures that we 'leave the irq code' once
 974          * we are out of the entry depth. Thus protecting us from
 975          * the RETURN entry loss.
 976          */
 977         if (*depth_irq >= depth) {
 978                 *depth_irq = -1;
 979                 return 1;
 980         }
 981
 982         /*
 983          * We are inside the irq code, and this is not the entry.
 984          */
 985         return 1;
 986 }
 987
 988 static enum print_line_t
 989 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 990                         struct trace_iterator *iter, u32 flags)
 991 {
 992         struct fgraph_data *data = iter->private;
 993         struct ftrace_graph_ent *call = &field->graph_ent;
 994         struct ftrace_graph_ret_entry *leaf_ret;
 995         static enum print_line_t ret;
 996         int cpu = iter->cpu;
 997
 998         if (check_irq_entry(iter, flags, call->func, call->depth))
 999                 return TRACE_TYPE_HANDLED;
1000
1001         print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
1002
1003         leaf_ret = get_return_for_leaf(iter, field);
1004         if (leaf_ret)
1005                 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1006         else
1007                 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1008
1009         if (data) {
1010                 /*
1011                  * If we failed to write our output, then we need to make
1012                  * note of it. Because we already consumed our entry.
1013                  */
1014                 if (s->full) {
1015                         data->failed = 1;
1016                         data->cpu = cpu;
1017                 } else
1018                         data->failed = 0;
1019         }
1020
1021         return ret;
1022 }
1023
1024 static enum print_line_t
1025 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1026                    struct trace_entry *ent, struct trace_iterator *iter,
1027                    u32 flags)
1028 {
1029         unsigned long long duration = trace->rettime - trace->calltime;
1030         struct fgraph_data *data = iter->private;
1031         pid_t pid = ent->pid;
1032         int cpu = iter->cpu;
1033         int func_match = 1;
1034         int i;
1035
1036         if (check_irq_return(iter, flags, trace->depth))
1037                 return TRACE_TYPE_HANDLED;
1038
1039         if (data) {
1040                 struct fgraph_cpu_data *cpu_data;
1041                 int cpu = iter->cpu;
1042
1043                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1044
1045                 /*
1046                  * Comments display at + 1 to depth. This is the
1047                  * return from a function, we now want the comments
1048                  * to display at the same level of the bracket.
1049                  */
1050                 cpu_data->depth = trace->depth - 1;
1051
1052                 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
1053                         if (cpu_data->enter_funcs[trace->depth] != trace->func)
1054                                 func_match = 0;
1055                         cpu_data->enter_funcs[trace->depth] = 0;
1056                 }
1057         }
1058
1059         print_graph_prologue(iter, s, 0, 0, flags);
1060
1061         /* Overhead and duration */
1062         print_graph_duration(duration, s, flags);
1063
1064         /* Closing brace */
1065         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
1066                 trace_seq_putc(s, ' ');
1067
1068         /*
1069          * If the return function does not have a matching entry,
1070          * then the entry was lost. Instead of just printing
1071          * the '}' and letting the user guess what function this
1072          * belongs to, write out the function name. Always do
1073          * that if the funcgraph-tail option is enabled.
1074          */
1075         if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
1076                 trace_seq_puts(s, "}\n");
1077         else
1078                 trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1079
1080         /* Overrun */
1081         if (flags & TRACE_GRAPH_PRINT_OVERRUN)
1082                 trace_seq_printf(s, " (Overruns: %lu)\n",
1083                                  trace->overrun);
1084
1085         print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1086                         cpu, pid, flags);
1087
1088         return trace_handle_return(s);
1089 }
1090
1091 static enum print_line_t
1092 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1093                     struct trace_iterator *iter, u32 flags)
1094 {
1095         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1096         struct fgraph_data *data = iter->private;
1097         struct trace_event *event;
1098         int depth = 0;
1099         int ret;
1100         int i;
1101
1102         if (data)
1103                 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1104
1105         print_graph_prologue(iter, s, 0, 0, flags);
1106
1107         /* No time */
1108         print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
1109
1110         /* Indentation */
1111         if (depth > 0)
1112                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
1113                         trace_seq_putc(s, ' ');
1114
1115         /* The comment */
1116         trace_seq_puts(s, "/* ");
1117
1118         switch (iter->ent->type) {
1119         case TRACE_BPRINT:
1120                 ret = trace_print_bprintk_msg_only(iter);
1121                 if (ret != TRACE_TYPE_HANDLED)
1122                         return ret;
1123                 break;
1124         case TRACE_PRINT:
1125                 ret = trace_print_printk_msg_only(iter);
1126                 if (ret != TRACE_TYPE_HANDLED)
1127                         return ret;
1128                 break;
1129         default:
1130                 event = ftrace_find_event(ent->type);
1131                 if (!event)
1132                         return TRACE_TYPE_UNHANDLED;
1133
1134                 ret = event->funcs->trace(iter, sym_flags, event);
1135                 if (ret != TRACE_TYPE_HANDLED)
1136                         return ret;
1137         }
1138
1139         if (trace_seq_has_overflowed(s))
1140                 goto out;
1141
1142         /* Strip ending newline */
1143         if (s->buffer[s->seq.len - 1] == '\n') {
1144                 s->buffer[s->seq.len - 1] = '\0';
1145                 s->seq.len--;
1146         }
1147
1148         trace_seq_puts(s, " */\n");
1149  out:
1150         return trace_handle_return(s);
1151 }
1152
1153
1154 enum print_line_t
1155 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1156 {
1157         struct ftrace_graph_ent_entry *field;
1158         struct fgraph_data *data = iter->private;
1159         struct trace_entry *entry = iter->ent;
1160         struct trace_seq *s = &iter->seq;
1161         int cpu = iter->cpu;
1162         int ret;
1163
1164         if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1165                 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1166                 return TRACE_TYPE_HANDLED;
1167         }
1168
1169         /*
1170          * If the last output failed, there's a possibility we need
1171          * to print out the missing entry which would never go out.
1172          */
1173         if (data && data->failed) {
1174                 field = &data->ent;
1175                 iter->cpu = data->cpu;
1176                 ret = print_graph_entry(field, s, iter, flags);
1177                 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1178                         per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1179                         ret = TRACE_TYPE_NO_CONSUME;
1180                 }
1181                 iter->cpu = cpu;
1182                 return ret;
1183         }
1184
1185         switch (entry->type) {
1186         case TRACE_GRAPH_ENT: {
1187                 /*
1188                  * print_graph_entry() may consume the current event,
1189                  * thus @field may become invalid, so we need to save it.
1190                  * sizeof(struct ftrace_graph_ent_entry) is very small,
1191                  * it can be safely saved at the stack.
1192                  */
1193                 struct ftrace_graph_ent_entry saved;
1194                 trace_assign_type(field, entry);
1195                 saved = *field;
1196                 return print_graph_entry(&saved, s, iter, flags);
1197         }
1198         case TRACE_GRAPH_RET: {
1199                 struct ftrace_graph_ret_entry *field;
1200                 trace_assign_type(field, entry);
1201                 return print_graph_return(&field->ret, s, entry, iter, flags);
1202         }
1203         case TRACE_STACK:
1204         case TRACE_FN:
1205                 /* dont trace stack and functions as comments */
1206                 return TRACE_TYPE_UNHANDLED;
1207
1208         default:
1209                 return print_graph_comment(s, entry, iter, flags);
1210         }
1211
1212         return TRACE_TYPE_HANDLED;
1213 }
1214
1215 static enum print_line_t
1216 print_graph_function(struct trace_iterator *iter)
1217 {
1218         return print_graph_function_flags(iter, tracer_flags.val);
1219 }
1220
1221 static enum print_line_t
1222 print_graph_function_event(struct trace_iterator *iter, int flags,
1223                            struct trace_event *event)
1224 {
1225         return print_graph_function(iter);
1226 }
1227
1228 static void print_lat_header(struct seq_file *s, u32 flags)
1229 {
1230         static const char spaces[] = "                " /* 16 spaces */
1231                 "    "                                  /* 4 spaces */
1232                 "                 ";                    /* 17 spaces */
1233         int size = 0;
1234
1235         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1236                 size += 16;
1237         if (flags & TRACE_GRAPH_PRINT_CPU)
1238                 size += 4;
1239         if (flags & TRACE_GRAPH_PRINT_PROC)
1240                 size += 17;
1241
1242         seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
1243         seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
1244         seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1245         seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
1246         seq_printf(s, "#%.*s||| /                      \n", size, spaces);
1247 }
1248
1249 static void __print_graph_headers_flags(struct seq_file *s, u32 flags)
1250 {
1251         int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
1252
1253         if (lat)
1254                 print_lat_header(s, flags);
1255
1256         /* 1st line */
1257         seq_putc(s, '#');
1258         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1259                 seq_puts(s, "     TIME       ");
1260         if (flags & TRACE_GRAPH_PRINT_CPU)
1261                 seq_puts(s, " CPU");
1262         if (flags & TRACE_GRAPH_PRINT_PROC)
1263                 seq_puts(s, "  TASK/PID       ");
1264         if (lat)
1265                 seq_puts(s, "||||");
1266         if (flags & TRACE_GRAPH_PRINT_DURATION)
1267                 seq_puts(s, "  DURATION   ");
1268         seq_puts(s, "               FUNCTION CALLS\n");
1269
1270         /* 2nd line */
1271         seq_putc(s, '#');
1272         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1273                 seq_puts(s, "      |         ");
1274         if (flags & TRACE_GRAPH_PRINT_CPU)
1275                 seq_puts(s, " |  ");
1276         if (flags & TRACE_GRAPH_PRINT_PROC)
1277                 seq_puts(s, "   |    |        ");
1278         if (lat)
1279                 seq_puts(s, "||||");
1280         if (flags & TRACE_GRAPH_PRINT_DURATION)
1281                 seq_puts(s, "   |   |      ");
1282         seq_puts(s, "               |   |   |   |\n");
1283 }
1284
1285 static void print_graph_headers(struct seq_file *s)
1286 {
1287         print_graph_headers_flags(s, tracer_flags.val);
1288 }
1289
1290 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1291 {
1292         struct trace_iterator *iter = s->private;
1293
1294         if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
1295                 return;
1296
1297         if (trace_flags & TRACE_ITER_LATENCY_FMT) {
1298                 /* print nothing if the buffers are empty */
1299                 if (trace_empty(iter))
1300                         return;
1301
1302                 print_trace_header(s, iter);
1303         }
1304
1305         __print_graph_headers_flags(s, flags);
1306 }
1307
1308 void graph_trace_open(struct trace_iterator *iter)
1309 {
1310         /* pid and depth on the last trace processed */
1311         struct fgraph_data *data;
1312         gfp_t gfpflags;
1313         int cpu;
1314
1315         iter->private = NULL;
1316
1317         /* We can be called in atomic context via ftrace_dump() */
1318         gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
1319
1320         data = kzalloc(sizeof(*data), gfpflags);
1321         if (!data)
1322                 goto out_err;
1323
1324         data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
1325         if (!data->cpu_data)
1326                 goto out_err_free;
1327
1328         for_each_possible_cpu(cpu) {
1329                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1330                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1331                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1332                 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1333
1334                 *pid = -1;
1335                 *depth = 0;
1336                 *ignore = 0;
1337                 *depth_irq = -1;
1338         }
1339
1340         iter->private = data;
1341
1342         return;
1343
1344  out_err_free:
1345         kfree(data);
1346  out_err:
1347         pr_warning("function graph tracer: not enough memory\n");
1348 }
1349
1350 void graph_trace_close(struct trace_iterator *iter)
1351 {
1352         struct fgraph_data *data = iter->private;
1353
1354         if (data) {
1355                 free_percpu(data->cpu_data);
1356                 kfree(data);
1357         }
1358 }
1359
1360 static int
1361 func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1362 {
1363         if (bit == TRACE_GRAPH_PRINT_IRQS)
1364                 ftrace_graph_skip_irqs = !set;
1365
1366         return 0;
1367 }
1368
1369 static struct trace_event_functions graph_functions = {
1370         .trace          = print_graph_function_event,
1371 };
1372
1373 static struct trace_event graph_trace_entry_event = {
1374         .type           = TRACE_GRAPH_ENT,
1375         .funcs          = &graph_functions,
1376 };
1377
1378 static struct trace_event graph_trace_ret_event = {
1379         .type           = TRACE_GRAPH_RET,
1380         .funcs          = &graph_functions
1381 };
1382
1383 static struct tracer graph_trace __tracer_data = {
1384         .name           = "function_graph",
1385         .update_thresh  = graph_trace_update_thresh,
1386         .open           = graph_trace_open,
1387         .pipe_open      = graph_trace_open,
1388         .close          = graph_trace_close,
1389         .pipe_close     = graph_trace_close,
1390         .init           = graph_trace_init,
1391         .reset          = graph_trace_reset,
1392         .print_line     = print_graph_function,
1393         .print_header   = print_graph_headers,
1394         .flags          = &tracer_flags,
1395         .set_flag       = func_graph_set_flag,
1396 #ifdef CONFIG_FTRACE_SELFTEST
1397         .selftest       = trace_selftest_startup_function_graph,
1398 #endif
1399 };
1400
1401
1402 static ssize_t
1403 graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1404                   loff_t *ppos)
1405 {
1406         unsigned long val;
1407         int ret;
1408
1409         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1410         if (ret)
1411                 return ret;
1412
1413         max_depth = val;
1414
1415         *ppos += cnt;
1416
1417         return cnt;
1418 }
1419
1420 static ssize_t
1421 graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1422                  loff_t *ppos)
1423 {
1424         char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1425         int n;
1426
1427         n = sprintf(buf, "%d\n", max_depth);
1428
1429         return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1430 }
1431
1432 static const struct file_operations graph_depth_fops = {
1433         .open           = tracing_open_generic,
1434         .write          = graph_depth_write,
1435         .read           = graph_depth_read,
1436         .llseek         = generic_file_llseek,
1437 };
1438
1439 static __init int init_graph_debugfs(void)
1440 {
1441         struct dentry *d_tracer;
1442
1443         d_tracer = tracing_init_dentry();
1444         if (IS_ERR(d_tracer))
1445                 return 0;
1446
1447         trace_create_file("max_graph_depth", 0644, d_tracer,
1448                           NULL, &graph_depth_fops);
1449
1450         return 0;
1451 }
1452 fs_initcall(init_graph_debugfs);
1453
1454 static __init int init_graph_trace(void)
1455 {
1456         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1457
1458         if (!register_ftrace_event(&graph_trace_entry_event)) {
1459                 pr_warning("Warning: could not register graph trace events\n");
1460                 return 1;
1461         }
1462
1463         if (!register_ftrace_event(&graph_trace_ret_event)) {
1464                 pr_warning("Warning: could not register graph trace events\n");
1465                 return 1;
1466         }
1467
1468         return register_tracer(&graph_trace);
1469 }
1470
1471 core_initcall(init_graph_trace);