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