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/interrupt.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         /* Include sleep time (scheduled out) between entry and return */
  88         { TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
  89         /* Include time within nested functions */
  90         { TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
  91         { } /* Empty entry */
  92 };
  93
  94 static struct tracer_flags tracer_flags = {
  95         /* Don't display overruns, proc, or tail by default */
  96         .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
  97                TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS |
  98                TRACE_GRAPH_SLEEP_TIME | TRACE_GRAPH_GRAPH_TIME,
  99         .opts = trace_opts
 100 };
 101
 102 static struct trace_array *graph_array;
 103
 104 /*
 105  * DURATION column is being also used to display IRQ signs,
 106  * following values are used by print_graph_irq and others
 107  * to fill in space into DURATION column.
 108  */
 109 enum {
 110         FLAGS_FILL_FULL  = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 111         FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 112         FLAGS_FILL_END   = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 113 };
 114
 115 static void
 116 print_graph_duration(struct trace_array *tr, unsigned long long duration,
 117                      struct trace_seq *s, u32 flags);
 118
 119 /* Add a function return address to the trace stack on thread info.*/
 120 int
 121 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 122                          unsigned long frame_pointer)
 123 {
 124         unsigned long long calltime;
 125         int index;
 126
 127         if (unlikely(ftrace_graph_is_dead()))
 128                 return -EBUSY;
 129
 130         if (!current->ret_stack)
 131                 return -EBUSY;
 132
 133         /*
 134          * We must make sure the ret_stack is tested before we read
 135          * anything else.
 136          */
 137         smp_rmb();
 138
 139         /* The return trace stack is full */
 140         if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
 141                 atomic_inc(&current->trace_overrun);
 142                 return -EBUSY;
 143         }
 144
 145         /*
 146          * The curr_ret_stack is an index to ftrace return stack of
 147          * current task.  Its value should be in [0, FTRACE_RETFUNC_
 148          * DEPTH) when the function graph tracer is used.  To support
 149          * filtering out specific functions, it makes the index
 150          * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
 151          * so when it sees a negative index the ftrace will ignore
 152          * the record.  And the index gets recovered when returning
 153          * from the filtered function by adding the FTRACE_NOTRACE_
 154          * DEPTH and then it'll continue to record functions normally.
 155          *
 156          * The curr_ret_stack is initialized to -1 and get increased
 157          * in this function.  So it can be less than -1 only if it was
 158          * filtered out via ftrace_graph_notrace_addr() which can be
 159          * set from set_graph_notrace file in tracefs by user.
 160          */
 161         if (current->curr_ret_stack < -1)
 162                 return -EBUSY;
 163
 164         calltime = trace_clock_local();
 165
 166         index = ++current->curr_ret_stack;
 167         if (ftrace_graph_notrace_addr(func))
 168                 current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
 169         barrier();
 170         current->ret_stack[index].ret = ret;
 171         current->ret_stack[index].func = func;
 172         current->ret_stack[index].calltime = calltime;
 173         current->ret_stack[index].fp = frame_pointer;
 174         *depth = current->curr_ret_stack;
 175
 176         return 0;
 177 }
 178
 179 /* Retrieve a function return address to the trace stack on thread info.*/
 180 static void
 181 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
 182                         unsigned long frame_pointer)
 183 {
 184         int index;
 185
 186         index = current->curr_ret_stack;
 187
 188         /*
 189          * A negative index here means that it's just returned from a
 190          * notrace'd function.  Recover index to get an original
 191          * return address.  See ftrace_push_return_trace().
 192          *
 193          * TODO: Need to check whether the stack gets corrupted.
 194          */
 195         if (index < 0)
 196                 index += FTRACE_NOTRACE_DEPTH;
 197
 198         if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
 199                 ftrace_graph_stop();
 200                 WARN_ON(1);
 201                 /* Might as well panic, otherwise we have no where to go */
 202                 *ret = (unsigned long)panic;
 203                 return;
 204         }
 205
 206 #if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY)
 207         /*
 208          * The arch may choose to record the frame pointer used
 209          * and check it here to make sure that it is what we expect it
 210          * to be. If gcc does not set the place holder of the return
 211          * address in the frame pointer, and does a copy instead, then
 212          * the function graph trace will fail. This test detects this
 213          * case.
 214          *
 215          * Currently, x86_32 with optimize for size (-Os) makes the latest
 216          * gcc do the above.
 217          *
 218          * Note, -mfentry does not use frame pointers, and this test
 219          *  is not needed if CC_USING_FENTRY is set.
 220          */
 221         if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
 222                 ftrace_graph_stop();
 223                 WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
 224                      "  from func %ps return to %lx\n",
 225                      current->ret_stack[index].fp,
 226                      frame_pointer,
 227                      (void *)current->ret_stack[index].func,
 228                      current->ret_stack[index].ret);
 229                 *ret = (unsigned long)panic;
 230                 return;
 231         }
 232 #endif
 233
 234         *ret = current->ret_stack[index].ret;
 235         trace->func = current->ret_stack[index].func;
 236         trace->calltime = current->ret_stack[index].calltime;
 237         trace->overrun = atomic_read(&current->trace_overrun);
 238         trace->depth = index;
 239 }
 240
 241 /*
 242  * Send the trace to the ring-buffer.
 243  * @return the original return address.
 244  */
 245 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 246 {
 247         struct ftrace_graph_ret trace;
 248         unsigned long ret;
 249
 250         ftrace_pop_return_trace(&trace, &ret, frame_pointer);
 251         trace.rettime = trace_clock_local();
 252         barrier();
 253         current->curr_ret_stack--;
 254         /*
 255          * The curr_ret_stack can be less than -1 only if it was
 256          * filtered out and it's about to return from the function.
 257          * Recover the index and continue to trace normal functions.
 258          */
 259         if (current->curr_ret_stack < -1) {
 260                 current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
 261                 return ret;
 262         }
 263
 264         /*
 265          * The trace should run after decrementing the ret counter
 266          * in case an interrupt were to come in. We don't want to
 267          * lose the interrupt if max_depth is set.
 268          */
 269         ftrace_graph_return(&trace);
 270
 271         if (unlikely(!ret)) {
 272                 ftrace_graph_stop();
 273                 WARN_ON(1);
 274                 /* Might as well panic. What else to do? */
 275                 ret = (unsigned long)panic;
 276         }
 277
 278         return ret;
 279 }
 280
 281 int __trace_graph_entry(struct trace_array *tr,
 282                                 struct ftrace_graph_ent *trace,
 283                                 unsigned long flags,
 284                                 int pc)
 285 {
 286         struct trace_event_call *call = &event_funcgraph_entry;
 287         struct ring_buffer_event *event;
 288         struct ring_buffer *buffer = tr->trace_buffer.buffer;
 289         struct ftrace_graph_ent_entry *entry;
 290
 291         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
 292                                           sizeof(*entry), flags, pc);
 293         if (!event)
 294                 return 0;
 295         entry   = ring_buffer_event_data(event);
 296         entry->graph_ent                        = *trace;
 297         if (!call_filter_check_discard(call, entry, buffer, event))
 298                 __buffer_unlock_commit(buffer, event);
 299
 300         return 1;
 301 }
 302
 303 static inline int ftrace_graph_ignore_irqs(void)
 304 {
 305         if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
 306                 return 0;
 307
 308         return in_irq();
 309 }
 310
 311 int trace_graph_entry(struct ftrace_graph_ent *trace)
 312 {
 313         struct trace_array *tr = graph_array;
 314         struct trace_array_cpu *data;
 315         unsigned long flags;
 316         long disabled;
 317         int ret;
 318         int cpu;
 319         int pc;
 320
 321         if (!ftrace_trace_task(tr))
 322                 return 0;
 323
 324         /* trace it when it is-nested-in or is a function enabled. */
 325         if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
 326              ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
 327             (max_depth && trace->depth >= max_depth))
 328                 return 0;
 329
 330         /*
 331          * Do not trace a function if it's filtered by set_graph_notrace.
 332          * Make the index of ret stack negative to indicate that it should
 333          * ignore further functions.  But it needs its own ret stack entry
 334          * to recover the original index in order to continue tracing after
 335          * returning from the function.
 336          */
 337         if (ftrace_graph_notrace_addr(trace->func))
 338                 return 1;
 339
 340         /*
 341          * Stop here if tracing_threshold is set. We only write function return
 342          * events to the ring buffer.
 343          */
 344         if (tracing_thresh)
 345                 return 1;
 346
 347         local_irq_save(flags);
 348         cpu = raw_smp_processor_id();
 349         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 350         disabled = atomic_inc_return(&data->disabled);
 351         if (likely(disabled == 1)) {
 352                 pc = preempt_count();
 353                 ret = __trace_graph_entry(tr, trace, flags, pc);
 354         } else {
 355                 ret = 0;
 356         }
 357
 358         atomic_dec(&data->disabled);
 359         local_irq_restore(flags);
 360
 361         return ret;
 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 trace_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         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
 403                                           sizeof(*entry), flags, pc);
 404         if (!event)
 405                 return;
 406         entry   = ring_buffer_event_data(event);
 407         entry->ret                              = *trace;
 408         if (!call_filter_check_discard(call, entry, buffer, event))
 409                 __buffer_unlock_commit(buffer, event);
 410 }
 411
 412 void trace_graph_return(struct ftrace_graph_ret *trace)
 413 {
 414         struct trace_array *tr = graph_array;
 415         struct trace_array_cpu *data;
 416         unsigned long flags;
 417         long disabled;
 418         int cpu;
 419         int pc;
 420
 421         local_irq_save(flags);
 422         cpu = raw_smp_processor_id();
 423         data = per_cpu_ptr(tr->trace_buffer.data, cpu);
 424         disabled = atomic_inc_return(&data->disabled);
 425         if (likely(disabled == 1)) {
 426                 pc = preempt_count();
 427                 __trace_graph_return(tr, trace, flags, pc);
 428         }
 429         atomic_dec(&data->disabled);
 430         local_irq_restore(flags);
 431 }
 432
 433 void set_graph_array(struct trace_array *tr)
 434 {
 435         graph_array = tr;
 436
 437         /* Make graph_array visible before we start tracing */
 438
 439         smp_mb();
 440 }
 441
 442 static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 443 {
 444         if (tracing_thresh &&
 445             (trace->rettime - trace->calltime < tracing_thresh))
 446                 return;
 447         else
 448                 trace_graph_return(trace);
 449 }
 450
 451 static int graph_trace_init(struct trace_array *tr)
 452 {
 453         int ret;
 454
 455         set_graph_array(tr);
 456         if (tracing_thresh)
 457                 ret = register_ftrace_graph(&trace_graph_thresh_return,
 458                                             &trace_graph_entry);
 459         else
 460                 ret = register_ftrace_graph(&trace_graph_return,
 461                                             &trace_graph_entry);
 462         if (ret)
 463                 return ret;
 464         tracing_start_cmdline_record();
 465
 466         return 0;
 467 }
 468
 469 static void graph_trace_reset(struct trace_array *tr)
 470 {
 471         tracing_stop_cmdline_record();
 472         unregister_ftrace_graph();
 473 }
 474
 475 static int graph_trace_update_thresh(struct trace_array *tr)
 476 {
 477         graph_trace_reset(tr);
 478         return graph_trace_init(tr);
 479 }
 480
 481 static int max_bytes_for_cpu;
 482
 483 static void print_graph_cpu(struct trace_seq *s, int cpu)
 484 {
 485         /*
 486          * Start with a space character - to make it stand out
 487          * to the right a bit when trace output is pasted into
 488          * email:
 489          */
 490         trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 491 }
 492
 493 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 494
 495 static void print_graph_proc(struct trace_seq *s, pid_t pid)
 496 {
 497         char comm[TASK_COMM_LEN];
 498         /* sign + log10(MAX_INT) + '\0' */
 499         char pid_str[11];
 500         int spaces = 0;
 501         int len;
 502         int i;
 503
 504         trace_find_cmdline(pid, comm);
 505         comm[7] = '\0';
 506         sprintf(pid_str, "%d", pid);
 507
 508         /* 1 stands for the "-" character */
 509         len = strlen(comm) + strlen(pid_str) + 1;
 510
 511         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 512                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 513
 514         /* First spaces to align center */
 515         for (i = 0; i < spaces / 2; i++)
 516                 trace_seq_putc(s, ' ');
 517
 518         trace_seq_printf(s, "%s-%s", comm, pid_str);
 519
 520         /* Last spaces to align center */
 521         for (i = 0; i < spaces - (spaces / 2); i++)
 522                 trace_seq_putc(s, ' ');
 523 }
 524
 525
 526 static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 527 {
 528         trace_seq_putc(s, ' ');
 529         trace_print_lat_fmt(s, entry);
 530 }
 531
 532 /* If the pid changed since the last trace, output this event */
 533 static void
 534 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 535 {
 536         pid_t prev_pid;
 537         pid_t *last_pid;
 538
 539         if (!data)
 540                 return;
 541
 542         last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
 543
 544         if (*last_pid == pid)
 545                 return;
 546
 547         prev_pid = *last_pid;
 548         *last_pid = pid;
 549
 550         if (prev_pid == -1)
 551                 return;
 552 /*
 553  * Context-switch trace line:
 554
 555  ------------------------------------------
 556  | 1)  migration/0--1  =>  sshd-1755
 557  ------------------------------------------
 558
 559  */
 560         trace_seq_puts(s, " ------------------------------------------\n");
 561         print_graph_cpu(s, cpu);
 562         print_graph_proc(s, prev_pid);
 563         trace_seq_puts(s, " => ");
 564         print_graph_proc(s, pid);
 565         trace_seq_puts(s, "\n ------------------------------------------\n\n");
 566 }
 567
 568 static struct ftrace_graph_ret_entry *
 569 get_return_for_leaf(struct trace_iterator *iter,
 570                 struct ftrace_graph_ent_entry *curr)
 571 {
 572         struct fgraph_data *data = iter->private;
 573         struct ring_buffer_iter *ring_iter = NULL;
 574         struct ring_buffer_event *event;
 575         struct ftrace_graph_ret_entry *next;
 576
 577         /*
 578          * If the previous output failed to write to the seq buffer,
 579          * then we just reuse the data from before.
 580          */
 581         if (data && data->failed) {
 582                 curr = &data->ent;
 583                 next = &data->ret;
 584         } else {
 585
 586                 ring_iter = trace_buffer_iter(iter, iter->cpu);
 587
 588                 /* First peek to compare current entry and the next one */
 589                 if (ring_iter)
 590                         event = ring_buffer_iter_peek(ring_iter, NULL);
 591                 else {
 592                         /*
 593                          * We need to consume the current entry to see
 594                          * the next one.
 595                          */
 596                         ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
 597                                             NULL, NULL);
 598                         event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
 599                                                  NULL, NULL);
 600                 }
 601
 602                 if (!event)
 603                         return NULL;
 604
 605                 next = ring_buffer_event_data(event);
 606
 607                 if (data) {
 608                         /*
 609                          * Save current and next entries for later reference
 610                          * if the output fails.
 611                          */
 612                         data->ent = *curr;
 613                         /*
 614                          * If the next event is not a return type, then
 615                          * we only care about what type it is. Otherwise we can
 616                          * safely copy the entire event.
 617                          */
 618                         if (next->ent.type == TRACE_GRAPH_RET)
 619                                 data->ret = *next;
 620                         else
 621                                 data->ret.ent.type = next->ent.type;
 622                 }
 623         }
 624
 625         if (next->ent.type != TRACE_GRAPH_RET)
 626                 return NULL;
 627
 628         if (curr->ent.pid != next->ent.pid ||
 629                         curr->graph_ent.func != next->ret.func)
 630                 return NULL;
 631
 632         /* this is a leaf, now advance the iterator */
 633         if (ring_iter)
 634                 ring_buffer_read(ring_iter, NULL);
 635
 636         return next;
 637 }
 638
 639 static void print_graph_abs_time(u64 t, struct trace_seq *s)
 640 {
 641         unsigned long usecs_rem;
 642
 643         usecs_rem = do_div(t, NSEC_PER_SEC);
 644         usecs_rem /= 1000;
 645
 646         trace_seq_printf(s, "%5lu.%06lu |  ",
 647                          (unsigned long)t, usecs_rem);
 648 }
 649
 650 static void
 651 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 652                 enum trace_type type, int cpu, pid_t pid, u32 flags)
 653 {
 654         struct trace_array *tr = iter->tr;
 655         struct trace_seq *s = &iter->seq;
 656         struct trace_entry *ent = iter->ent;
 657
 658         if (addr < (unsigned long)__irqentry_text_start ||
 659                 addr >= (unsigned long)__irqentry_text_end)
 660                 return;
 661
 662         if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
 663                 /* Absolute time */
 664                 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 665                         print_graph_abs_time(iter->ts, s);
 666
 667                 /* Cpu */
 668                 if (flags & TRACE_GRAPH_PRINT_CPU)
 669                         print_graph_cpu(s, cpu);
 670
 671                 /* Proc */
 672                 if (flags & TRACE_GRAPH_PRINT_PROC) {
 673                         print_graph_proc(s, pid);
 674                         trace_seq_puts(s, " | ");
 675                 }
 676
 677                 /* Latency format */
 678                 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
 679                         print_graph_lat_fmt(s, ent);
 680         }
 681
 682         /* No overhead */
 683         print_graph_duration(tr, 0, s, flags | FLAGS_FILL_START);
 684
 685         if (type == TRACE_GRAPH_ENT)
 686                 trace_seq_puts(s, "==========>");
 687         else
 688                 trace_seq_puts(s, "<==========");
 689
 690         print_graph_duration(tr, 0, s, flags | FLAGS_FILL_END);
 691         trace_seq_putc(s, '\n');
 692 }
 693
 694 void
 695 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 696 {
 697         unsigned long nsecs_rem = do_div(duration, 1000);
 698         /* log10(ULONG_MAX) + '\0' */
 699         char usecs_str[21];
 700         char nsecs_str[5];
 701         int len;
 702         int i;
 703
 704         sprintf(usecs_str, "%lu", (unsigned long) duration);
 705
 706         /* Print msecs */
 707         trace_seq_printf(s, "%s", usecs_str);
 708
 709         len = strlen(usecs_str);
 710
 711         /* Print nsecs (we don't want to exceed 7 numbers) */
 712         if (len < 7) {
 713                 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
 714
 715                 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
 716                 trace_seq_printf(s, ".%s", nsecs_str);
 717                 len += strlen(nsecs_str) + 1;
 718         }
 719
 720         trace_seq_puts(s, " us ");
 721
 722         /* Print remaining spaces to fit the row's width */
 723         for (i = len; i < 8; i++)
 724                 trace_seq_putc(s, ' ');
 725 }
 726
 727 static void
 728 print_graph_duration(struct trace_array *tr, unsigned long long duration,
 729                      struct trace_seq *s, u32 flags)
 730 {
 731         if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
 732             !(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
 733                 return;
 734
 735         /* No real adata, just filling the column with spaces */
 736         switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
 737         case FLAGS_FILL_FULL:
 738                 trace_seq_puts(s, "              |  ");
 739                 return;
 740         case FLAGS_FILL_START:
 741                 trace_seq_puts(s, "  ");
 742                 return;
 743         case FLAGS_FILL_END:
 744                 trace_seq_puts(s, " |");
 745                 return;
 746         }
 747
 748         /* Signal a overhead of time execution to the output */
 749         if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
 750                 trace_seq_printf(s, "%c ", trace_find_mark(duration));
 751         else
 752                 trace_seq_puts(s, "  ");
 753
 754         trace_print_graph_duration(duration, s);
 755         trace_seq_puts(s, "|  ");
 756 }
 757
 758 /* Case of a leaf function on its call entry */
 759 static enum print_line_t
 760 print_graph_entry_leaf(struct trace_iterator *iter,
 761                 struct ftrace_graph_ent_entry *entry,
 762                 struct ftrace_graph_ret_entry *ret_entry,
 763                 struct trace_seq *s, u32 flags)
 764 {
 765         struct fgraph_data *data = iter->private;
 766         struct trace_array *tr = iter->tr;
 767         struct ftrace_graph_ret *graph_ret;
 768         struct ftrace_graph_ent *call;
 769         unsigned long long duration;
 770         int i;
 771
 772         graph_ret = &ret_entry->ret;
 773         call = &entry->graph_ent;
 774         duration = graph_ret->rettime - graph_ret->calltime;
 775
 776         if (data) {
 777                 struct fgraph_cpu_data *cpu_data;
 778                 int cpu = iter->cpu;
 779
 780                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 781
 782                 /*
 783                  * Comments display at + 1 to depth. Since
 784                  * this is a leaf function, keep the comments
 785                  * equal to this depth.
 786                  */
 787                 cpu_data->depth = call->depth - 1;
 788
 789                 /* No need to keep this function around for this depth */
 790                 if (call->depth < FTRACE_RETFUNC_DEPTH)
 791                         cpu_data->enter_funcs[call->depth] = 0;
 792         }
 793
 794         /* Overhead and duration */
 795         print_graph_duration(tr, duration, s, flags);
 796
 797         /* Function */
 798         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
 799                 trace_seq_putc(s, ' ');
 800
 801         trace_seq_printf(s, "%ps();\n", (void *)call->func);
 802
 803         return trace_handle_return(s);
 804 }
 805
 806 static enum print_line_t
 807 print_graph_entry_nested(struct trace_iterator *iter,
 808                          struct ftrace_graph_ent_entry *entry,
 809                          struct trace_seq *s, int cpu, u32 flags)
 810 {
 811         struct ftrace_graph_ent *call = &entry->graph_ent;
 812         struct fgraph_data *data = iter->private;
 813         struct trace_array *tr = iter->tr;
 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(tr, 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         struct trace_array *tr = iter->tr;
 854         int cpu = iter->cpu;
 855
 856         /* Pid */
 857         verif_pid(s, ent->pid, cpu, data);
 858
 859         if (type)
 860                 /* Interrupt */
 861                 print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
 862
 863         if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
 864                 return;
 865
 866         /* Absolute time */
 867         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 868                 print_graph_abs_time(iter->ts, s);
 869
 870         /* Cpu */
 871         if (flags & TRACE_GRAPH_PRINT_CPU)
 872                 print_graph_cpu(s, cpu);
 873
 874         /* Proc */
 875         if (flags & TRACE_GRAPH_PRINT_PROC) {
 876                 print_graph_proc(s, ent->pid);
 877                 trace_seq_puts(s, " | ");
 878         }
 879
 880         /* Latency format */
 881         if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
 882                 print_graph_lat_fmt(s, ent);
 883
 884         return;
 885 }
 886
 887 /*
 888  * Entry check for irq code
 889  *
 890  * returns 1 if
 891  *  - we are inside irq code
 892  *  - we just entered irq code
 893  *
 894  * retunns 0 if
 895  *  - funcgraph-interrupts option is set
 896  *  - we are not inside irq code
 897  */
 898 static int
 899 check_irq_entry(struct trace_iterator *iter, u32 flags,
 900                 unsigned long addr, int depth)
 901 {
 902         int cpu = iter->cpu;
 903         int *depth_irq;
 904         struct fgraph_data *data = iter->private;
 905
 906         /*
 907          * If we are either displaying irqs, or we got called as
 908          * a graph event and private data does not exist,
 909          * then we bypass the irq check.
 910          */
 911         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
 912             (!data))
 913                 return 0;
 914
 915         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 916
 917         /*
 918          * We are inside the irq code
 919          */
 920         if (*depth_irq >= 0)
 921                 return 1;
 922
 923         if ((addr < (unsigned long)__irqentry_text_start) ||
 924             (addr >= (unsigned long)__irqentry_text_end))
 925                 return 0;
 926
 927         /*
 928          * We are entering irq code.
 929          */
 930         *depth_irq = depth;
 931         return 1;
 932 }
 933
 934 /*
 935  * Return check for irq code
 936  *
 937  * returns 1 if
 938  *  - we are inside irq code
 939  *  - we just left irq code
 940  *
 941  * returns 0 if
 942  *  - funcgraph-interrupts option is set
 943  *  - we are not inside irq code
 944  */
 945 static int
 946 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
 947 {
 948         int cpu = iter->cpu;
 949         int *depth_irq;
 950         struct fgraph_data *data = iter->private;
 951
 952         /*
 953          * If we are either displaying irqs, or we got called as
 954          * a graph event and private data does not exist,
 955          * then we bypass the irq check.
 956          */
 957         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
 958             (!data))
 959                 return 0;
 960
 961         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 962
 963         /*
 964          * We are not inside the irq code.
 965          */
 966         if (*depth_irq == -1)
 967                 return 0;
 968
 969         /*
 970          * We are inside the irq code, and this is returning entry.
 971          * Let's not trace it and clear the entry depth, since
 972          * we are out of irq code.
 973          *
 974          * This condition ensures that we 'leave the irq code' once
 975          * we are out of the entry depth. Thus protecting us from
 976          * the RETURN entry loss.
 977          */
 978         if (*depth_irq >= depth) {
 979                 *depth_irq = -1;
 980                 return 1;
 981         }
 982
 983         /*
 984          * We are inside the irq code, and this is not the entry.
 985          */
 986         return 1;
 987 }
 988
 989 static enum print_line_t
 990 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 991                         struct trace_iterator *iter, u32 flags)
 992 {
 993         struct fgraph_data *data = iter->private;
 994         struct ftrace_graph_ent *call = &field->graph_ent;
 995         struct ftrace_graph_ret_entry *leaf_ret;
 996         static enum print_line_t ret;
 997         int cpu = iter->cpu;
 998
 999         if (check_irq_entry(iter, flags, call->func, call->depth))
1000                 return TRACE_TYPE_HANDLED;
1001
1002         print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
1003
1004         leaf_ret = get_return_for_leaf(iter, field);
1005         if (leaf_ret)
1006                 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
1007         else
1008                 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
1009
1010         if (data) {
1011                 /*
1012                  * If we failed to write our output, then we need to make
1013                  * note of it. Because we already consumed our entry.
1014                  */
1015                 if (s->full) {
1016                         data->failed = 1;
1017                         data->cpu = cpu;
1018                 } else
1019                         data->failed = 0;
1020         }
1021
1022         return ret;
1023 }
1024
1025 static enum print_line_t
1026 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
1027                    struct trace_entry *ent, struct trace_iterator *iter,
1028                    u32 flags)
1029 {
1030         unsigned long long duration = trace->rettime - trace->calltime;
1031         struct fgraph_data *data = iter->private;
1032         struct trace_array *tr = iter->tr;
1033         pid_t pid = ent->pid;
1034         int cpu = iter->cpu;
1035         int func_match = 1;
1036         int i;
1037
1038         if (check_irq_return(iter, flags, trace->depth))
1039                 return TRACE_TYPE_HANDLED;
1040
1041         if (data) {
1042                 struct fgraph_cpu_data *cpu_data;
1043                 int cpu = iter->cpu;
1044
1045                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
1046
1047                 /*
1048                  * Comments display at + 1 to depth. This is the
1049                  * return from a function, we now want the comments
1050                  * to display at the same level of the bracket.
1051                  */
1052                 cpu_data->depth = trace->depth - 1;
1053
1054                 if (trace->depth < FTRACE_RETFUNC_DEPTH) {
1055                         if (cpu_data->enter_funcs[trace->depth] != trace->func)
1056                                 func_match = 0;
1057                         cpu_data->enter_funcs[trace->depth] = 0;
1058                 }
1059         }
1060
1061         print_graph_prologue(iter, s, 0, 0, flags);
1062
1063         /* Overhead and duration */
1064         print_graph_duration(tr, duration, s, flags);
1065
1066         /* Closing brace */
1067         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
1068                 trace_seq_putc(s, ' ');
1069
1070         /*
1071          * If the return function does not have a matching entry,
1072          * then the entry was lost. Instead of just printing
1073          * the '}' and letting the user guess what function this
1074          * belongs to, write out the function name. Always do
1075          * that if the funcgraph-tail option is enabled.
1076          */
1077         if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
1078                 trace_seq_puts(s, "}\n");
1079         else
1080                 trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1081
1082         /* Overrun */
1083         if (flags & TRACE_GRAPH_PRINT_OVERRUN)
1084                 trace_seq_printf(s, " (Overruns: %lu)\n",
1085                                  trace->overrun);
1086
1087         print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1088                         cpu, pid, flags);
1089
1090         return trace_handle_return(s);
1091 }
1092
1093 static enum print_line_t
1094 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1095                     struct trace_iterator *iter, u32 flags)
1096 {
1097         struct trace_array *tr = iter->tr;
1098         unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
1099         struct fgraph_data *data = iter->private;
1100         struct trace_event *event;
1101         int depth = 0;
1102         int ret;
1103         int i;
1104
1105         if (data)
1106                 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1107
1108         print_graph_prologue(iter, s, 0, 0, flags);
1109
1110         /* No time */
1111         print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
1112
1113         /* Indentation */
1114         if (depth > 0)
1115                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
1116                         trace_seq_putc(s, ' ');
1117
1118         /* The comment */
1119         trace_seq_puts(s, "/* ");
1120
1121         switch (iter->ent->type) {
1122         case TRACE_BPUTS:
1123                 ret = trace_print_bputs_msg_only(iter);
1124                 if (ret != TRACE_TYPE_HANDLED)
1125                         return ret;
1126                 break;
1127         case TRACE_BPRINT:
1128                 ret = trace_print_bprintk_msg_only(iter);
1129                 if (ret != TRACE_TYPE_HANDLED)
1130                         return ret;
1131                 break;
1132         case TRACE_PRINT:
1133                 ret = trace_print_printk_msg_only(iter);
1134                 if (ret != TRACE_TYPE_HANDLED)
1135                         return ret;
1136                 break;
1137         default:
1138                 event = ftrace_find_event(ent->type);
1139                 if (!event)
1140                         return TRACE_TYPE_UNHANDLED;
1141
1142                 ret = event->funcs->trace(iter, sym_flags, event);
1143                 if (ret != TRACE_TYPE_HANDLED)
1144                         return ret;
1145         }
1146
1147         if (trace_seq_has_overflowed(s))
1148                 goto out;
1149
1150         /* Strip ending newline */
1151         if (s->buffer[s->seq.len - 1] == '\n') {
1152                 s->buffer[s->seq.len - 1] = '\0';
1153                 s->seq.len--;
1154         }
1155
1156         trace_seq_puts(s, " */\n");
1157  out:
1158         return trace_handle_return(s);
1159 }
1160
1161
1162 enum print_line_t
1163 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1164 {
1165         struct ftrace_graph_ent_entry *field;
1166         struct fgraph_data *data = iter->private;
1167         struct trace_entry *entry = iter->ent;
1168         struct trace_seq *s = &iter->seq;
1169         int cpu = iter->cpu;
1170         int ret;
1171
1172         if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1173                 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1174                 return TRACE_TYPE_HANDLED;
1175         }
1176
1177         /*
1178          * If the last output failed, there's a possibility we need
1179          * to print out the missing entry which would never go out.
1180          */
1181         if (data && data->failed) {
1182                 field = &data->ent;
1183                 iter->cpu = data->cpu;
1184                 ret = print_graph_entry(field, s, iter, flags);
1185                 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1186                         per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1187                         ret = TRACE_TYPE_NO_CONSUME;
1188                 }
1189                 iter->cpu = cpu;
1190                 return ret;
1191         }
1192
1193         switch (entry->type) {
1194         case TRACE_GRAPH_ENT: {
1195                 /*
1196                  * print_graph_entry() may consume the current event,
1197                  * thus @field may become invalid, so we need to save it.
1198                  * sizeof(struct ftrace_graph_ent_entry) is very small,
1199                  * it can be safely saved at the stack.
1200                  */
1201                 struct ftrace_graph_ent_entry saved;
1202                 trace_assign_type(field, entry);
1203                 saved = *field;
1204                 return print_graph_entry(&saved, s, iter, flags);
1205         }
1206         case TRACE_GRAPH_RET: {
1207                 struct ftrace_graph_ret_entry *field;
1208                 trace_assign_type(field, entry);
1209                 return print_graph_return(&field->ret, s, entry, iter, flags);
1210         }
1211         case TRACE_STACK:
1212         case TRACE_FN:
1213                 /* dont trace stack and functions as comments */
1214                 return TRACE_TYPE_UNHANDLED;
1215
1216         default:
1217                 return print_graph_comment(s, entry, iter, flags);
1218         }
1219
1220         return TRACE_TYPE_HANDLED;
1221 }
1222
1223 static enum print_line_t
1224 print_graph_function(struct trace_iterator *iter)
1225 {
1226         return print_graph_function_flags(iter, tracer_flags.val);
1227 }
1228
1229 static enum print_line_t
1230 print_graph_function_event(struct trace_iterator *iter, int flags,
1231                            struct trace_event *event)
1232 {
1233         return print_graph_function(iter);
1234 }
1235
1236 static void print_lat_header(struct seq_file *s, u32 flags)
1237 {
1238         static const char spaces[] = "                " /* 16 spaces */
1239                 "    "                                  /* 4 spaces */
1240                 "                 ";                    /* 17 spaces */
1241         int size = 0;
1242
1243         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1244                 size += 16;
1245         if (flags & TRACE_GRAPH_PRINT_CPU)
1246                 size += 4;
1247         if (flags & TRACE_GRAPH_PRINT_PROC)
1248                 size += 17;
1249
1250         seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
1251         seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
1252         seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1253         seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
1254         seq_printf(s, "#%.*s||| /                      \n", size, spaces);
1255 }
1256
1257 static void __print_graph_headers_flags(struct trace_array *tr,
1258                                         struct seq_file *s, u32 flags)
1259 {
1260         int lat = tr->trace_flags & TRACE_ITER_LATENCY_FMT;
1261
1262         if (lat)
1263                 print_lat_header(s, flags);
1264
1265         /* 1st line */
1266         seq_putc(s, '#');
1267         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1268                 seq_puts(s, "     TIME       ");
1269         if (flags & TRACE_GRAPH_PRINT_CPU)
1270                 seq_puts(s, " CPU");
1271         if (flags & TRACE_GRAPH_PRINT_PROC)
1272                 seq_puts(s, "  TASK/PID       ");
1273         if (lat)
1274                 seq_puts(s, "||||");
1275         if (flags & TRACE_GRAPH_PRINT_DURATION)
1276                 seq_puts(s, "  DURATION   ");
1277         seq_puts(s, "               FUNCTION CALLS\n");
1278
1279         /* 2nd line */
1280         seq_putc(s, '#');
1281         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1282                 seq_puts(s, "      |         ");
1283         if (flags & TRACE_GRAPH_PRINT_CPU)
1284                 seq_puts(s, " |  ");
1285         if (flags & TRACE_GRAPH_PRINT_PROC)
1286                 seq_puts(s, "   |    |        ");
1287         if (lat)
1288                 seq_puts(s, "||||");
1289         if (flags & TRACE_GRAPH_PRINT_DURATION)
1290                 seq_puts(s, "   |   |      ");
1291         seq_puts(s, "               |   |   |   |\n");
1292 }
1293
1294 static void print_graph_headers(struct seq_file *s)
1295 {
1296         print_graph_headers_flags(s, tracer_flags.val);
1297 }
1298
1299 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1300 {
1301         struct trace_iterator *iter = s->private;
1302         struct trace_array *tr = iter->tr;
1303
1304         if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
1305                 return;
1306
1307         if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) {
1308                 /* print nothing if the buffers are empty */
1309                 if (trace_empty(iter))
1310                         return;
1311
1312                 print_trace_header(s, iter);
1313         }
1314
1315         __print_graph_headers_flags(tr, s, flags);
1316 }
1317
1318 void graph_trace_open(struct trace_iterator *iter)
1319 {
1320         /* pid and depth on the last trace processed */
1321         struct fgraph_data *data;
1322         gfp_t gfpflags;
1323         int cpu;
1324
1325         iter->private = NULL;
1326
1327         /* We can be called in atomic context via ftrace_dump() */
1328         gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
1329
1330         data = kzalloc(sizeof(*data), gfpflags);
1331         if (!data)
1332                 goto out_err;
1333
1334         data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
1335         if (!data->cpu_data)
1336                 goto out_err_free;
1337
1338         for_each_possible_cpu(cpu) {
1339                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1340                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1341                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1342                 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1343
1344                 *pid = -1;
1345                 *depth = 0;
1346                 *ignore = 0;
1347                 *depth_irq = -1;
1348         }
1349
1350         iter->private = data;
1351
1352         return;
1353
1354  out_err_free:
1355         kfree(data);
1356  out_err:
1357         pr_warn("function graph tracer: not enough memory\n");
1358 }
1359
1360 void graph_trace_close(struct trace_iterator *iter)
1361 {
1362         struct fgraph_data *data = iter->private;
1363
1364         if (data) {
1365                 free_percpu(data->cpu_data);
1366                 kfree(data);
1367         }
1368 }
1369
1370 static int
1371 func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1372 {
1373         if (bit == TRACE_GRAPH_PRINT_IRQS)
1374                 ftrace_graph_skip_irqs = !set;
1375
1376         if (bit == TRACE_GRAPH_SLEEP_TIME)
1377                 ftrace_graph_sleep_time_control(set);
1378
1379         if (bit == TRACE_GRAPH_GRAPH_TIME)
1380                 ftrace_graph_graph_time_control(set);
1381
1382         return 0;
1383 }
1384
1385 static struct trace_event_functions graph_functions = {
1386         .trace          = print_graph_function_event,
1387 };
1388
1389 static struct trace_event graph_trace_entry_event = {
1390         .type           = TRACE_GRAPH_ENT,
1391         .funcs          = &graph_functions,
1392 };
1393
1394 static struct trace_event graph_trace_ret_event = {
1395         .type           = TRACE_GRAPH_RET,
1396         .funcs          = &graph_functions
1397 };
1398
1399 static struct tracer graph_trace __tracer_data = {
1400         .name           = "function_graph",
1401         .update_thresh  = graph_trace_update_thresh,
1402         .open           = graph_trace_open,
1403         .pipe_open      = graph_trace_open,
1404         .close          = graph_trace_close,
1405         .pipe_close     = graph_trace_close,
1406         .init           = graph_trace_init,
1407         .reset          = graph_trace_reset,
1408         .print_line     = print_graph_function,
1409         .print_header   = print_graph_headers,
1410         .flags          = &tracer_flags,
1411         .set_flag       = func_graph_set_flag,
1412 #ifdef CONFIG_FTRACE_SELFTEST
1413         .selftest       = trace_selftest_startup_function_graph,
1414 #endif
1415 };
1416
1417
1418 static ssize_t
1419 graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1420                   loff_t *ppos)
1421 {
1422         unsigned long val;
1423         int ret;
1424
1425         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1426         if (ret)
1427                 return ret;
1428
1429         max_depth = val;
1430
1431         *ppos += cnt;
1432
1433         return cnt;
1434 }
1435
1436 static ssize_t
1437 graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1438                  loff_t *ppos)
1439 {
1440         char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1441         int n;
1442
1443         n = sprintf(buf, "%d\n", max_depth);
1444
1445         return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1446 }
1447
1448 static const struct file_operations graph_depth_fops = {
1449         .open           = tracing_open_generic,
1450         .write          = graph_depth_write,
1451         .read           = graph_depth_read,
1452         .llseek         = generic_file_llseek,
1453 };
1454
1455 static __init int init_graph_tracefs(void)
1456 {
1457         struct dentry *d_tracer;
1458
1459         d_tracer = tracing_init_dentry();
1460         if (IS_ERR(d_tracer))
1461                 return 0;
1462
1463         trace_create_file("max_graph_depth", 0644, d_tracer,
1464                           NULL, &graph_depth_fops);
1465
1466         return 0;
1467 }
1468 fs_initcall(init_graph_tracefs);
1469
1470 static __init int init_graph_trace(void)
1471 {
1472         max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
1473
1474         if (!register_trace_event(&graph_trace_entry_event)) {
1475                 pr_warn("Warning: could not register graph trace events\n");
1476                 return 1;
1477         }
1478
1479         if (!register_trace_event(&graph_trace_ret_event)) {
1480                 pr_warn("Warning: could not register graph trace events\n");
1481                 return 1;
1482         }
1483
1484         return register_tracer(&graph_trace);
1485 }
1486
1487 core_initcall(init_graph_trace);