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