kernel/trace/trace_functions_graph.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *
   4  * Function graph tracer.
   5  * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
   6  * Mostly borrowed from function tracer which
   7  * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
   8  *
   9  */
  10 #include <linux/uaccess.h>
  11 #include <linux/ftrace.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/slab.h>
  14 #include <linux/fs.h>
  15
  16 #include "trace.h"
  17 #include "trace_output.h"
  18
  19 /* When set, irq functions will be ignored */
  20 static int ftrace_graph_skip_irqs;
  21
  22 struct fgraph_cpu_data {
  23         pid_t           last_pid;
  24         int             depth;
  25         int             depth_irq;
  26         int             ignore;
  27         unsigned long   enter_funcs[FTRACE_RETFUNC_DEPTH];
  28 };
  29
  30 struct fgraph_data {
  31         struct fgraph_cpu_data __percpu *cpu_data;
  32
  33         /* Place to preserve last processed entry. */
  34         struct ftrace_graph_ent_entry   ent;
  35         struct ftrace_graph_ret_entry   ret;
  36         int                             failed;
  37         int                             cpu;
  38 };
  39
  40 #define TRACE_GRAPH_INDENT      2
  41
  42 unsigned int fgraph_max_depth;
  43
  44 static struct tracer_opt trace_opts[] = {
  45         /* Display overruns? (for self-debug purpose) */
  46         { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
  47         /* Display CPU ? */
  48         { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
  49         /* Display Overhead ? */
  50         { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
  51         /* Display proc name/pid */
  52         { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
  53         /* Display duration of execution */
  54         { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
  55         /* Display absolute time of an entry */
  56         { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
  57         /* Display interrupts */
  58         { TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
  59         /* Display function name after trailing } */
  60         { TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
  61 #ifdef CONFIG_FUNCTION_GRAPH_RETVAL
  62         /* Display function return value ? */
  63         { TRACER_OPT(funcgraph-retval, TRACE_GRAPH_PRINT_RETVAL) },
  64         /* Display function return value in hexadecimal format ? */
  65         { TRACER_OPT(funcgraph-retval-hex, TRACE_GRAPH_PRINT_RETVAL_HEX) },
  66 #endif
  67         /* Include sleep time (scheduled out) between entry and return */
  68         { TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
  69
  70 #ifdef CONFIG_FUNCTION_PROFILER
  71         /* Include time within nested functions */
  72         { TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
  73 #endif
  74
  75         { } /* Empty entry */
  76 };
  77
  78 static struct tracer_flags tracer_flags = {
  79         /* Don't display overruns, proc, or tail by default */
  80         .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
  81                TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS |
  82                TRACE_GRAPH_SLEEP_TIME | TRACE_GRAPH_GRAPH_TIME,
  83         .opts = trace_opts
  84 };
  85
  86 static struct trace_array *graph_array;
  87
  88 /*
  89  * DURATION column is being also used to display IRQ signs,
  90  * following values are used by print_graph_irq and others
  91  * to fill in space into DURATION column.
  92  */
  93 enum {
  94         FLAGS_FILL_FULL  = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
  95         FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
  96         FLAGS_FILL_END   = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
  97 };
  98
  99 static void
 100 print_graph_duration(struct trace_array *tr, unsigned long long duration,
 101                      struct trace_seq *s, u32 flags);
 102
 103 int __trace_graph_entry(struct trace_array *tr,
 104                                 struct ftrace_graph_ent *trace,
 105                                 unsigned int trace_ctx)
 106 {
 107         struct trace_event_call *call = &event_funcgraph_entry;
 108         struct ring_buffer_event *event;
 109         struct trace_buffer *buffer = tr->array_buffer.buffer;
 110         struct ftrace_graph_ent_entry *entry;
 111
 112         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
 113                                           sizeof(*entry), trace_ctx);
 114         if (!event)
 115                 return 0;
 116         entry   = ring_buffer_event_data(event);
 117         entry->graph_ent                        = *trace;
 118         if (!call_filter_check_discard(call, entry, buffer, event))
 119                 trace_buffer_unlock_commit_nostack(buffer, event);
 120
 121         return 1;
 122 }
 123
 124 static inline int ftrace_graph_ignore_irqs(void)
 125 {
 126         if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
 127                 return 0;
 128
 129         return in_hardirq();
 130 }
 131
 132 int trace_graph_entry(struct ftrace_graph_ent *trace)
 133 {
 134         struct trace_array *tr = graph_array;
 135         struct trace_array_cpu *data;
 136         unsigned long flags;
 137         unsigned int trace_ctx;
 138         long disabled;
 139         int ret;
 140         int cpu;
 141
 142         if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
 143                 return 0;
 144
 145         /*
 146          * Do not trace a function if it's filtered by set_graph_notrace.
 147          * Make the index of ret stack negative to indicate that it should
 148          * ignore further functions.  But it needs its own ret stack entry
 149          * to recover the original index in order to continue tracing after
 150          * returning from the function.
 151          */
 152         if (ftrace_graph_notrace_addr(trace->func)) {
 153                 trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
 154                 /*
 155                  * Need to return 1 to have the return called
 156                  * that will clear the NOTRACE bit.
 157                  */
 158                 return 1;
 159         }
 160
 161         if (!ftrace_trace_task(tr))
 162                 return 0;
 163
 164         if (ftrace_graph_ignore_func(trace))
 165                 return 0;
 166
 167         if (ftrace_graph_ignore_irqs())
 168                 return 0;
 169
 170         /*
 171          * Stop here if tracing_threshold is set. We only write function return
 172          * events to the ring buffer.
 173          */
 174         if (tracing_thresh)
 175                 return 1;
 176
 177         local_irq_save(flags);
 178         cpu = raw_smp_processor_id();
 179         data = per_cpu_ptr(tr->array_buffer.data, cpu);
 180         disabled = atomic_inc_return(&data->disabled);
 181         if (likely(disabled == 1)) {
 182                 trace_ctx = tracing_gen_ctx_flags(flags);
 183                 ret = __trace_graph_entry(tr, trace, trace_ctx);
 184         } else {
 185                 ret = 0;
 186         }
 187
 188         atomic_dec(&data->disabled);
 189         local_irq_restore(flags);
 190
 191         return ret;
 192 }
 193
 194 static void
 195 __trace_graph_function(struct trace_array *tr,
 196                 unsigned long ip, unsigned int trace_ctx)
 197 {
 198         u64 time = trace_clock_local();
 199         struct ftrace_graph_ent ent = {
 200                 .func  = ip,
 201                 .depth = 0,
 202         };
 203         struct ftrace_graph_ret ret = {
 204                 .func     = ip,
 205                 .depth    = 0,
 206                 .calltime = time,
 207                 .rettime  = time,
 208         };
 209
 210         __trace_graph_entry(tr, &ent, trace_ctx);
 211         __trace_graph_return(tr, &ret, trace_ctx);
 212 }
 213
 214 void
 215 trace_graph_function(struct trace_array *tr,
 216                 unsigned long ip, unsigned long parent_ip,
 217                 unsigned int trace_ctx)
 218 {
 219         __trace_graph_function(tr, ip, trace_ctx);
 220 }
 221
 222 void __trace_graph_return(struct trace_array *tr,
 223                                 struct ftrace_graph_ret *trace,
 224                                 unsigned int trace_ctx)
 225 {
 226         struct trace_event_call *call = &event_funcgraph_exit;
 227         struct ring_buffer_event *event;
 228         struct trace_buffer *buffer = tr->array_buffer.buffer;
 229         struct ftrace_graph_ret_entry *entry;
 230
 231         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
 232                                           sizeof(*entry), trace_ctx);
 233         if (!event)
 234                 return;
 235         entry   = ring_buffer_event_data(event);
 236         entry->ret                              = *trace;
 237         if (!call_filter_check_discard(call, entry, buffer, event))
 238                 trace_buffer_unlock_commit_nostack(buffer, event);
 239 }
 240
 241 void trace_graph_return(struct ftrace_graph_ret *trace)
 242 {
 243         struct trace_array *tr = graph_array;
 244         struct trace_array_cpu *data;
 245         unsigned long flags;
 246         unsigned int trace_ctx;
 247         long disabled;
 248         int cpu;
 249
 250         ftrace_graph_addr_finish(trace);
 251
 252         if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
 253                 trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
 254                 return;
 255         }
 256
 257         local_irq_save(flags);
 258         cpu = raw_smp_processor_id();
 259         data = per_cpu_ptr(tr->array_buffer.data, cpu);
 260         disabled = atomic_inc_return(&data->disabled);
 261         if (likely(disabled == 1)) {
 262                 trace_ctx = tracing_gen_ctx_flags(flags);
 263                 __trace_graph_return(tr, trace, trace_ctx);
 264         }
 265         atomic_dec(&data->disabled);
 266         local_irq_restore(flags);
 267 }
 268
 269 void set_graph_array(struct trace_array *tr)
 270 {
 271         graph_array = tr;
 272
 273         /* Make graph_array visible before we start tracing */
 274
 275         smp_mb();
 276 }
 277
 278 static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 279 {
 280         ftrace_graph_addr_finish(trace);
 281
 282         if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
 283                 trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
 284                 return;
 285         }
 286
 287         if (tracing_thresh &&
 288             (trace->rettime - trace->calltime < tracing_thresh))
 289                 return;
 290         else
 291                 trace_graph_return(trace);
 292 }
 293
 294 static struct fgraph_ops funcgraph_thresh_ops = {
 295         .entryfunc = &trace_graph_entry,
 296         .retfunc = &trace_graph_thresh_return,
 297 };
 298
 299 static struct fgraph_ops funcgraph_ops = {
 300         .entryfunc = &trace_graph_entry,
 301         .retfunc = &trace_graph_return,
 302 };
 303
 304 static int graph_trace_init(struct trace_array *tr)
 305 {
 306         int ret;
 307
 308         set_graph_array(tr);
 309         if (tracing_thresh)
 310                 ret = register_ftrace_graph(&funcgraph_thresh_ops);
 311         else
 312                 ret = register_ftrace_graph(&funcgraph_ops);
 313         if (ret)
 314                 return ret;
 315         tracing_start_cmdline_record();
 316
 317         return 0;
 318 }
 319
 320 static void graph_trace_reset(struct trace_array *tr)
 321 {
 322         tracing_stop_cmdline_record();
 323         if (tracing_thresh)
 324                 unregister_ftrace_graph(&funcgraph_thresh_ops);
 325         else
 326                 unregister_ftrace_graph(&funcgraph_ops);
 327 }
 328
 329 static int graph_trace_update_thresh(struct trace_array *tr)
 330 {
 331         graph_trace_reset(tr);
 332         return graph_trace_init(tr);
 333 }
 334
 335 static int max_bytes_for_cpu;
 336
 337 static void print_graph_cpu(struct trace_seq *s, int cpu)
 338 {
 339         /*
 340          * Start with a space character - to make it stand out
 341          * to the right a bit when trace output is pasted into
 342          * email:
 343          */
 344         trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 345 }
 346
 347 #define TRACE_GRAPH_PROCINFO_LENGTH     14
 348
 349 static void print_graph_proc(struct trace_seq *s, pid_t pid)
 350 {
 351         char comm[TASK_COMM_LEN];
 352         /* sign + log10(MAX_INT) + '\0' */
 353         char pid_str[11];
 354         int spaces = 0;
 355         int len;
 356         int i;
 357
 358         trace_find_cmdline(pid, comm);
 359         comm[7] = '\0';
 360         sprintf(pid_str, "%d", pid);
 361
 362         /* 1 stands for the "-" character */
 363         len = strlen(comm) + strlen(pid_str) + 1;
 364
 365         if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 366                 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 367
 368         /* First spaces to align center */
 369         for (i = 0; i < spaces / 2; i++)
 370                 trace_seq_putc(s, ' ');
 371
 372         trace_seq_printf(s, "%s-%s", comm, pid_str);
 373
 374         /* Last spaces to align center */
 375         for (i = 0; i < spaces - (spaces / 2); i++)
 376                 trace_seq_putc(s, ' ');
 377 }
 378
 379
 380 static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 381 {
 382         trace_seq_putc(s, ' ');
 383         trace_print_lat_fmt(s, entry);
 384         trace_seq_puts(s, " | ");
 385 }
 386
 387 /* If the pid changed since the last trace, output this event */
 388 static void
 389 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 390 {
 391         pid_t prev_pid;
 392         pid_t *last_pid;
 393
 394         if (!data)
 395                 return;
 396
 397         last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
 398
 399         if (*last_pid == pid)
 400                 return;
 401
 402         prev_pid = *last_pid;
 403         *last_pid = pid;
 404
 405         if (prev_pid == -1)
 406                 return;
 407 /*
 408  * Context-switch trace line:
 409
 410  ------------------------------------------
 411  | 1)  migration/0--1  =>  sshd-1755
 412  ------------------------------------------
 413
 414  */
 415         trace_seq_puts(s, " ------------------------------------------\n");
 416         print_graph_cpu(s, cpu);
 417         print_graph_proc(s, prev_pid);
 418         trace_seq_puts(s, " => ");
 419         print_graph_proc(s, pid);
 420         trace_seq_puts(s, "\n ------------------------------------------\n\n");
 421 }
 422
 423 static struct ftrace_graph_ret_entry *
 424 get_return_for_leaf(struct trace_iterator *iter,
 425                 struct ftrace_graph_ent_entry *curr)
 426 {
 427         struct fgraph_data *data = iter->private;
 428         struct ring_buffer_iter *ring_iter = NULL;
 429         struct ring_buffer_event *event;
 430         struct ftrace_graph_ret_entry *next;
 431
 432         /*
 433          * If the previous output failed to write to the seq buffer,
 434          * then we just reuse the data from before.
 435          */
 436         if (data && data->failed) {
 437                 curr = &data->ent;
 438                 next = &data->ret;
 439         } else {
 440
 441                 ring_iter = trace_buffer_iter(iter, iter->cpu);
 442
 443                 /* First peek to compare current entry and the next one */
 444                 if (ring_iter)
 445                         event = ring_buffer_iter_peek(ring_iter, NULL);
 446                 else {
 447                         /*
 448                          * We need to consume the current entry to see
 449                          * the next one.
 450                          */
 451                         ring_buffer_consume(iter->array_buffer->buffer, iter->cpu,
 452                                             NULL, NULL);
 453                         event = ring_buffer_peek(iter->array_buffer->buffer, iter->cpu,
 454                                                  NULL, NULL);
 455                 }
 456
 457                 if (!event)
 458                         return NULL;
 459
 460                 next = ring_buffer_event_data(event);
 461
 462                 if (data) {
 463                         /*
 464                          * Save current and next entries for later reference
 465                          * if the output fails.
 466                          */
 467                         data->ent = *curr;
 468                         /*
 469                          * If the next event is not a return type, then
 470                          * we only care about what type it is. Otherwise we can
 471                          * safely copy the entire event.
 472                          */
 473                         if (next->ent.type == TRACE_GRAPH_RET)
 474                                 data->ret = *next;
 475                         else
 476                                 data->ret.ent.type = next->ent.type;
 477                 }
 478         }
 479
 480         if (next->ent.type != TRACE_GRAPH_RET)
 481                 return NULL;
 482
 483         if (curr->ent.pid != next->ent.pid ||
 484                         curr->graph_ent.func != next->ret.func)
 485                 return NULL;
 486
 487         /* this is a leaf, now advance the iterator */
 488         if (ring_iter)
 489                 ring_buffer_iter_advance(ring_iter);
 490
 491         return next;
 492 }
 493
 494 static void print_graph_abs_time(u64 t, struct trace_seq *s)
 495 {
 496         unsigned long usecs_rem;
 497
 498         usecs_rem = do_div(t, NSEC_PER_SEC);
 499         usecs_rem /= 1000;
 500
 501         trace_seq_printf(s, "%5lu.%06lu |  ",
 502                          (unsigned long)t, usecs_rem);
 503 }
 504
 505 static void
 506 print_graph_rel_time(struct trace_iterator *iter, struct trace_seq *s)
 507 {
 508         unsigned long long usecs;
 509
 510         usecs = iter->ts - iter->array_buffer->time_start;
 511         do_div(usecs, NSEC_PER_USEC);
 512
 513         trace_seq_printf(s, "%9llu us |  ", usecs);
 514 }
 515
 516 static void
 517 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 518                 enum trace_type type, int cpu, pid_t pid, u32 flags)
 519 {
 520         struct trace_array *tr = iter->tr;
 521         struct trace_seq *s = &iter->seq;
 522         struct trace_entry *ent = iter->ent;
 523
 524         if (addr < (unsigned long)__irqentry_text_start ||
 525                 addr >= (unsigned long)__irqentry_text_end)
 526                 return;
 527
 528         if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
 529                 /* Absolute time */
 530                 if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 531                         print_graph_abs_time(iter->ts, s);
 532
 533                 /* Relative time */
 534                 if (flags & TRACE_GRAPH_PRINT_REL_TIME)
 535                         print_graph_rel_time(iter, s);
 536
 537                 /* Cpu */
 538                 if (flags & TRACE_GRAPH_PRINT_CPU)
 539                         print_graph_cpu(s, cpu);
 540
 541                 /* Proc */
 542                 if (flags & TRACE_GRAPH_PRINT_PROC) {
 543                         print_graph_proc(s, pid);
 544                         trace_seq_puts(s, " | ");
 545                 }
 546
 547                 /* Latency format */
 548                 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
 549                         print_graph_lat_fmt(s, ent);
 550         }
 551
 552         /* No overhead */
 553         print_graph_duration(tr, 0, s, flags | FLAGS_FILL_START);
 554
 555         if (type == TRACE_GRAPH_ENT)
 556                 trace_seq_puts(s, "==========>");
 557         else
 558                 trace_seq_puts(s, "<==========");
 559
 560         print_graph_duration(tr, 0, s, flags | FLAGS_FILL_END);
 561         trace_seq_putc(s, '\n');
 562 }
 563
 564 void
 565 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 566 {
 567         unsigned long nsecs_rem = do_div(duration, 1000);
 568         /* log10(ULONG_MAX) + '\0' */
 569         char usecs_str[21];
 570         char nsecs_str[5];
 571         int len;
 572         int i;
 573
 574         sprintf(usecs_str, "%lu", (unsigned long) duration);
 575
 576         /* Print msecs */
 577         trace_seq_printf(s, "%s", usecs_str);
 578
 579         len = strlen(usecs_str);
 580
 581         /* Print nsecs (we don't want to exceed 7 numbers) */
 582         if (len < 7) {
 583                 size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
 584
 585                 snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
 586                 trace_seq_printf(s, ".%s", nsecs_str);
 587                 len += strlen(nsecs_str) + 1;
 588         }
 589
 590         trace_seq_puts(s, " us ");
 591
 592         /* Print remaining spaces to fit the row's width */
 593         for (i = len; i < 8; i++)
 594                 trace_seq_putc(s, ' ');
 595 }
 596
 597 static void
 598 print_graph_duration(struct trace_array *tr, unsigned long long duration,
 599                      struct trace_seq *s, u32 flags)
 600 {
 601         if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
 602             !(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
 603                 return;
 604
 605         /* No real adata, just filling the column with spaces */
 606         switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
 607         case FLAGS_FILL_FULL:
 608                 trace_seq_puts(s, "              |  ");
 609                 return;
 610         case FLAGS_FILL_START:
 611                 trace_seq_puts(s, "  ");
 612                 return;
 613         case FLAGS_FILL_END:
 614                 trace_seq_puts(s, " |");
 615                 return;
 616         }
 617
 618         /* Signal a overhead of time execution to the output */
 619         if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
 620                 trace_seq_printf(s, "%c ", trace_find_mark(duration));
 621         else
 622                 trace_seq_puts(s, "  ");
 623
 624         trace_print_graph_duration(duration, s);
 625         trace_seq_puts(s, "|  ");
 626 }
 627
 628 #ifdef CONFIG_FUNCTION_GRAPH_RETVAL
 629
 630 #define __TRACE_GRAPH_PRINT_RETVAL TRACE_GRAPH_PRINT_RETVAL
 631
 632 static void print_graph_retval(struct trace_seq *s, unsigned long retval,
 633                                 bool leaf, void *func, bool hex_format)
 634 {
 635         unsigned long err_code = 0;
 636
 637         if (retval == 0 || hex_format)
 638                 goto done;
 639
 640         /* Check if the return value matches the negative format */
 641         if (IS_ENABLED(CONFIG_64BIT) && (retval & BIT(31)) &&
 642                 (((u64)retval) >> 32) == 0) {
 643                 /* sign extension */
 644                 err_code = (unsigned long)(s32)retval;
 645         } else {
 646                 err_code = retval;
 647         }
 648
 649         if (!IS_ERR_VALUE(err_code))
 650                 err_code = 0;
 651
 652 done:
 653         if (leaf) {
 654                 if (hex_format || (err_code == 0))
 655                         trace_seq_printf(s, "%ps(); /* = 0x%lx */\n",
 656                                         func, retval);
 657                 else
 658                         trace_seq_printf(s, "%ps(); /* = %ld */\n",
 659                                         func, err_code);
 660         } else {
 661                 if (hex_format || (err_code == 0))
 662                         trace_seq_printf(s, "} /* %ps = 0x%lx */\n",
 663                                         func, retval);
 664                 else
 665                         trace_seq_printf(s, "} /* %ps = %ld */\n",
 666                                         func, err_code);
 667         }
 668 }
 669
 670 #else
 671
 672 #define __TRACE_GRAPH_PRINT_RETVAL 0
 673
 674 #define print_graph_retval(_seq, _retval, _leaf, _func, _format) do {} while (0)
 675
 676 #endif
 677
 678 /* Case of a leaf function on its call entry */
 679 static enum print_line_t
 680 print_graph_entry_leaf(struct trace_iterator *iter,
 681                 struct ftrace_graph_ent_entry *entry,
 682                 struct ftrace_graph_ret_entry *ret_entry,
 683                 struct trace_seq *s, u32 flags)
 684 {
 685         struct fgraph_data *data = iter->private;
 686         struct trace_array *tr = iter->tr;
 687         struct ftrace_graph_ret *graph_ret;
 688         struct ftrace_graph_ent *call;
 689         unsigned long long duration;
 690         int cpu = iter->cpu;
 691         int i;
 692
 693         graph_ret = &ret_entry->ret;
 694         call = &entry->graph_ent;
 695         duration = graph_ret->rettime - graph_ret->calltime;
 696
 697         if (data) {
 698                 struct fgraph_cpu_data *cpu_data;
 699
 700                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 701
 702                 /*
 703                  * Comments display at + 1 to depth. Since
 704                  * this is a leaf function, keep the comments
 705                  * equal to this depth.
 706                  */
 707                 cpu_data->depth = call->depth - 1;
 708
 709                 /* No need to keep this function around for this depth */
 710                 if (call->depth < FTRACE_RETFUNC_DEPTH &&
 711                     !WARN_ON_ONCE(call->depth < 0))
 712                         cpu_data->enter_funcs[call->depth] = 0;
 713         }
 714
 715         /* Overhead and duration */
 716         print_graph_duration(tr, duration, s, flags);
 717
 718         /* Function */
 719         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
 720                 trace_seq_putc(s, ' ');
 721
 722         /*
 723          * Write out the function return value if the option function-retval is
 724          * enabled.
 725          */
 726         if (flags & __TRACE_GRAPH_PRINT_RETVAL)
 727                 print_graph_retval(s, graph_ret->retval, true, (void *)call->func,
 728                                 !!(flags & TRACE_GRAPH_PRINT_RETVAL_HEX));
 729         else
 730                 trace_seq_printf(s, "%ps();\n", (void *)call->func);
 731
 732         print_graph_irq(iter, graph_ret->func, TRACE_GRAPH_RET,
 733                         cpu, iter->ent->pid, flags);
 734
 735         return trace_handle_return(s);
 736 }
 737
 738 static enum print_line_t
 739 print_graph_entry_nested(struct trace_iterator *iter,
 740                          struct ftrace_graph_ent_entry *entry,
 741                          struct trace_seq *s, int cpu, u32 flags)
 742 {
 743         struct ftrace_graph_ent *call = &entry->graph_ent;
 744         struct fgraph_data *data = iter->private;
 745         struct trace_array *tr = iter->tr;
 746         int i;
 747
 748         if (data) {
 749                 struct fgraph_cpu_data *cpu_data;
 750                 int cpu = iter->cpu;
 751
 752                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 753                 cpu_data->depth = call->depth;
 754
 755                 /* Save this function pointer to see if the exit matches */
 756                 if (call->depth < FTRACE_RETFUNC_DEPTH &&
 757                     !WARN_ON_ONCE(call->depth < 0))
 758                         cpu_data->enter_funcs[call->depth] = call->func;
 759         }
 760
 761         /* No time */
 762         print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
 763
 764         /* Function */
 765         for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
 766                 trace_seq_putc(s, ' ');
 767
 768         trace_seq_printf(s, "%ps() {\n", (void *)call->func);
 769
 770         if (trace_seq_has_overflowed(s))
 771                 return TRACE_TYPE_PARTIAL_LINE;
 772
 773         /*
 774          * we already consumed the current entry to check the next one
 775          * and see if this is a leaf.
 776          */
 777         return TRACE_TYPE_NO_CONSUME;
 778 }
 779
 780 static void
 781 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 782                      int type, unsigned long addr, u32 flags)
 783 {
 784         struct fgraph_data *data = iter->private;
 785         struct trace_entry *ent = iter->ent;
 786         struct trace_array *tr = iter->tr;
 787         int cpu = iter->cpu;
 788
 789         /* Pid */
 790         verif_pid(s, ent->pid, cpu, data);
 791
 792         if (type)
 793                 /* Interrupt */
 794                 print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
 795
 796         if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
 797                 return;
 798
 799         /* Absolute time */
 800         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 801                 print_graph_abs_time(iter->ts, s);
 802
 803         /* Relative time */
 804         if (flags & TRACE_GRAPH_PRINT_REL_TIME)
 805                 print_graph_rel_time(iter, s);
 806
 807         /* Cpu */
 808         if (flags & TRACE_GRAPH_PRINT_CPU)
 809                 print_graph_cpu(s, cpu);
 810
 811         /* Proc */
 812         if (flags & TRACE_GRAPH_PRINT_PROC) {
 813                 print_graph_proc(s, ent->pid);
 814                 trace_seq_puts(s, " | ");
 815         }
 816
 817         /* Latency format */
 818         if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
 819                 print_graph_lat_fmt(s, ent);
 820
 821         return;
 822 }
 823
 824 /*
 825  * Entry check for irq code
 826  *
 827  * returns 1 if
 828  *  - we are inside irq code
 829  *  - we just entered irq code
 830  *
 831  * returns 0 if
 832  *  - funcgraph-interrupts option is set
 833  *  - we are not inside irq code
 834  */
 835 static int
 836 check_irq_entry(struct trace_iterator *iter, u32 flags,
 837                 unsigned long addr, int depth)
 838 {
 839         int cpu = iter->cpu;
 840         int *depth_irq;
 841         struct fgraph_data *data = iter->private;
 842
 843         /*
 844          * If we are either displaying irqs, or we got called as
 845          * a graph event and private data does not exist,
 846          * then we bypass the irq check.
 847          */
 848         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
 849             (!data))
 850                 return 0;
 851
 852         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 853
 854         /*
 855          * We are inside the irq code
 856          */
 857         if (*depth_irq >= 0)
 858                 return 1;
 859
 860         if ((addr < (unsigned long)__irqentry_text_start) ||
 861             (addr >= (unsigned long)__irqentry_text_end))
 862                 return 0;
 863
 864         /*
 865          * We are entering irq code.
 866          */
 867         *depth_irq = depth;
 868         return 1;
 869 }
 870
 871 /*
 872  * Return check for irq code
 873  *
 874  * returns 1 if
 875  *  - we are inside irq code
 876  *  - we just left irq code
 877  *
 878  * returns 0 if
 879  *  - funcgraph-interrupts option is set
 880  *  - we are not inside irq code
 881  */
 882 static int
 883 check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
 884 {
 885         int cpu = iter->cpu;
 886         int *depth_irq;
 887         struct fgraph_data *data = iter->private;
 888
 889         /*
 890          * If we are either displaying irqs, or we got called as
 891          * a graph event and private data does not exist,
 892          * then we bypass the irq check.
 893          */
 894         if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
 895             (!data))
 896                 return 0;
 897
 898         depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
 899
 900         /*
 901          * We are not inside the irq code.
 902          */
 903         if (*depth_irq == -1)
 904                 return 0;
 905
 906         /*
 907          * We are inside the irq code, and this is returning entry.
 908          * Let's not trace it and clear the entry depth, since
 909          * we are out of irq code.
 910          *
 911          * This condition ensures that we 'leave the irq code' once
 912          * we are out of the entry depth. Thus protecting us from
 913          * the RETURN entry loss.
 914          */
 915         if (*depth_irq >= depth) {
 916                 *depth_irq = -1;
 917                 return 1;
 918         }
 919
 920         /*
 921          * We are inside the irq code, and this is not the entry.
 922          */
 923         return 1;
 924 }
 925
 926 static enum print_line_t
 927 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 928                         struct trace_iterator *iter, u32 flags)
 929 {
 930         struct fgraph_data *data = iter->private;
 931         struct ftrace_graph_ent *call = &field->graph_ent;
 932         struct ftrace_graph_ret_entry *leaf_ret;
 933         static enum print_line_t ret;
 934         int cpu = iter->cpu;
 935
 936         if (check_irq_entry(iter, flags, call->func, call->depth))
 937                 return TRACE_TYPE_HANDLED;
 938
 939         print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
 940
 941         leaf_ret = get_return_for_leaf(iter, field);
 942         if (leaf_ret)
 943                 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
 944         else
 945                 ret = print_graph_entry_nested(iter, field, s, cpu, flags);
 946
 947         if (data) {
 948                 /*
 949                  * If we failed to write our output, then we need to make
 950                  * note of it. Because we already consumed our entry.
 951                  */
 952                 if (s->full) {
 953                         data->failed = 1;
 954                         data->cpu = cpu;
 955                 } else
 956                         data->failed = 0;
 957         }
 958
 959         return ret;
 960 }
 961
 962 static enum print_line_t
 963 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 964                    struct trace_entry *ent, struct trace_iterator *iter,
 965                    u32 flags)
 966 {
 967         unsigned long long duration = trace->rettime - trace->calltime;
 968         struct fgraph_data *data = iter->private;
 969         struct trace_array *tr = iter->tr;
 970         pid_t pid = ent->pid;
 971         int cpu = iter->cpu;
 972         int func_match = 1;
 973         int i;
 974
 975         if (check_irq_return(iter, flags, trace->depth))
 976                 return TRACE_TYPE_HANDLED;
 977
 978         if (data) {
 979                 struct fgraph_cpu_data *cpu_data;
 980                 int cpu = iter->cpu;
 981
 982                 cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 983
 984                 /*
 985                  * Comments display at + 1 to depth. This is the
 986                  * return from a function, we now want the comments
 987                  * to display at the same level of the bracket.
 988                  */
 989                 cpu_data->depth = trace->depth - 1;
 990
 991                 if (trace->depth < FTRACE_RETFUNC_DEPTH &&
 992                     !WARN_ON_ONCE(trace->depth < 0)) {
 993                         if (cpu_data->enter_funcs[trace->depth] != trace->func)
 994                                 func_match = 0;
 995                         cpu_data->enter_funcs[trace->depth] = 0;
 996                 }
 997         }
 998
 999         print_graph_prologue(iter, s, 0, 0, flags);
1000
1001         /* Overhead and duration */
1002         print_graph_duration(tr, duration, s, flags);
1003
1004         /* Closing brace */
1005         for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
1006                 trace_seq_putc(s, ' ');
1007
1008         /*
1009          * Always write out the function name and its return value if the
1010          * function-retval option is enabled.
1011          */
1012         if (flags & __TRACE_GRAPH_PRINT_RETVAL) {
1013                 print_graph_retval(s, trace->retval, false, (void *)trace->func,
1014                         !!(flags & TRACE_GRAPH_PRINT_RETVAL_HEX));
1015         } else {
1016                 /*
1017                  * If the return function does not have a matching entry,
1018                  * then the entry was lost. Instead of just printing
1019                  * the '}' and letting the user guess what function this
1020                  * belongs to, write out the function name. Always do
1021                  * that if the funcgraph-tail option is enabled.
1022                  */
1023                 if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
1024                         trace_seq_puts(s, "}\n");
1025                 else
1026                         trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
1027         }
1028
1029         /* Overrun */
1030         if (flags & TRACE_GRAPH_PRINT_OVERRUN)
1031                 trace_seq_printf(s, " (Overruns: %u)\n",
1032                                  trace->overrun);
1033
1034         print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
1035                         cpu, pid, flags);
1036
1037         return trace_handle_return(s);
1038 }
1039
1040 static enum print_line_t
1041 print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
1042                     struct trace_iterator *iter, u32 flags)
1043 {
1044         struct trace_array *tr = iter->tr;
1045         unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
1046         struct fgraph_data *data = iter->private;
1047         struct trace_event *event;
1048         int depth = 0;
1049         int ret;
1050         int i;
1051
1052         if (data)
1053                 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
1054
1055         print_graph_prologue(iter, s, 0, 0, flags);
1056
1057         /* No time */
1058         print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
1059
1060         /* Indentation */
1061         if (depth > 0)
1062                 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
1063                         trace_seq_putc(s, ' ');
1064
1065         /* The comment */
1066         trace_seq_puts(s, "/* ");
1067
1068         switch (iter->ent->type) {
1069         case TRACE_BPUTS:
1070                 ret = trace_print_bputs_msg_only(iter);
1071                 if (ret != TRACE_TYPE_HANDLED)
1072                         return ret;
1073                 break;
1074         case TRACE_BPRINT:
1075                 ret = trace_print_bprintk_msg_only(iter);
1076                 if (ret != TRACE_TYPE_HANDLED)
1077                         return ret;
1078                 break;
1079         case TRACE_PRINT:
1080                 ret = trace_print_printk_msg_only(iter);
1081                 if (ret != TRACE_TYPE_HANDLED)
1082                         return ret;
1083                 break;
1084         default:
1085                 event = ftrace_find_event(ent->type);
1086                 if (!event)
1087                         return TRACE_TYPE_UNHANDLED;
1088
1089                 ret = event->funcs->trace(iter, sym_flags, event);
1090                 if (ret != TRACE_TYPE_HANDLED)
1091                         return ret;
1092         }
1093
1094         if (trace_seq_has_overflowed(s))
1095                 goto out;
1096
1097         /* Strip ending newline */
1098         if (s->buffer[s->seq.len - 1] == '\n') {
1099                 s->buffer[s->seq.len - 1] = '\0';
1100                 s->seq.len--;
1101         }
1102
1103         trace_seq_puts(s, " */\n");
1104  out:
1105         return trace_handle_return(s);
1106 }
1107
1108
1109 enum print_line_t
1110 print_graph_function_flags(struct trace_iterator *iter, u32 flags)
1111 {
1112         struct ftrace_graph_ent_entry *field;
1113         struct fgraph_data *data = iter->private;
1114         struct trace_entry *entry = iter->ent;
1115         struct trace_seq *s = &iter->seq;
1116         int cpu = iter->cpu;
1117         int ret;
1118
1119         if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
1120                 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
1121                 return TRACE_TYPE_HANDLED;
1122         }
1123
1124         /*
1125          * If the last output failed, there's a possibility we need
1126          * to print out the missing entry which would never go out.
1127          */
1128         if (data && data->failed) {
1129                 field = &data->ent;
1130                 iter->cpu = data->cpu;
1131                 ret = print_graph_entry(field, s, iter, flags);
1132                 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
1133                         per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
1134                         ret = TRACE_TYPE_NO_CONSUME;
1135                 }
1136                 iter->cpu = cpu;
1137                 return ret;
1138         }
1139
1140         switch (entry->type) {
1141         case TRACE_GRAPH_ENT: {
1142                 /*
1143                  * print_graph_entry() may consume the current event,
1144                  * thus @field may become invalid, so we need to save it.
1145                  * sizeof(struct ftrace_graph_ent_entry) is very small,
1146                  * it can be safely saved at the stack.
1147                  */
1148                 struct ftrace_graph_ent_entry saved;
1149                 trace_assign_type(field, entry);
1150                 saved = *field;
1151                 return print_graph_entry(&saved, s, iter, flags);
1152         }
1153         case TRACE_GRAPH_RET: {
1154                 struct ftrace_graph_ret_entry *field;
1155                 trace_assign_type(field, entry);
1156                 return print_graph_return(&field->ret, s, entry, iter, flags);
1157         }
1158         case TRACE_STACK:
1159         case TRACE_FN:
1160                 /* dont trace stack and functions as comments */
1161                 return TRACE_TYPE_UNHANDLED;
1162
1163         default:
1164                 return print_graph_comment(s, entry, iter, flags);
1165         }
1166
1167         return TRACE_TYPE_HANDLED;
1168 }
1169
1170 static enum print_line_t
1171 print_graph_function(struct trace_iterator *iter)
1172 {
1173         return print_graph_function_flags(iter, tracer_flags.val);
1174 }
1175
1176 static enum print_line_t
1177 print_graph_function_event(struct trace_iterator *iter, int flags,
1178                            struct trace_event *event)
1179 {
1180         return print_graph_function(iter);
1181 }
1182
1183 static void print_lat_header(struct seq_file *s, u32 flags)
1184 {
1185         static const char spaces[] = "                " /* 16 spaces */
1186                 "    "                                  /* 4 spaces */
1187                 "                 ";                    /* 17 spaces */
1188         int size = 0;
1189
1190         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1191                 size += 16;
1192         if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1193                 size += 16;
1194         if (flags & TRACE_GRAPH_PRINT_CPU)
1195                 size += 4;
1196         if (flags & TRACE_GRAPH_PRINT_PROC)
1197                 size += 17;
1198
1199         seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
1200         seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
1201         seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
1202         seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
1203         seq_printf(s, "#%.*s||| /                      \n", size, spaces);
1204 }
1205
1206 static void __print_graph_headers_flags(struct trace_array *tr,
1207                                         struct seq_file *s, u32 flags)
1208 {
1209         int lat = tr->trace_flags & TRACE_ITER_LATENCY_FMT;
1210
1211         if (lat)
1212                 print_lat_header(s, flags);
1213
1214         /* 1st line */
1215         seq_putc(s, '#');
1216         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1217                 seq_puts(s, "     TIME       ");
1218         if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1219                 seq_puts(s, "   REL TIME     ");
1220         if (flags & TRACE_GRAPH_PRINT_CPU)
1221                 seq_puts(s, " CPU");
1222         if (flags & TRACE_GRAPH_PRINT_PROC)
1223                 seq_puts(s, "  TASK/PID       ");
1224         if (lat)
1225                 seq_puts(s, "||||   ");
1226         if (flags & TRACE_GRAPH_PRINT_DURATION)
1227                 seq_puts(s, "  DURATION   ");
1228         seq_puts(s, "               FUNCTION CALLS\n");
1229
1230         /* 2nd line */
1231         seq_putc(s, '#');
1232         if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
1233                 seq_puts(s, "      |         ");
1234         if (flags & TRACE_GRAPH_PRINT_REL_TIME)
1235                 seq_puts(s, "      |         ");
1236         if (flags & TRACE_GRAPH_PRINT_CPU)
1237                 seq_puts(s, " |  ");
1238         if (flags & TRACE_GRAPH_PRINT_PROC)
1239                 seq_puts(s, "   |    |        ");
1240         if (lat)
1241                 seq_puts(s, "||||   ");
1242         if (flags & TRACE_GRAPH_PRINT_DURATION)
1243                 seq_puts(s, "   |   |      ");
1244         seq_puts(s, "               |   |   |   |\n");
1245 }
1246
1247 static void print_graph_headers(struct seq_file *s)
1248 {
1249         print_graph_headers_flags(s, tracer_flags.val);
1250 }
1251
1252 void print_graph_headers_flags(struct seq_file *s, u32 flags)
1253 {
1254         struct trace_iterator *iter = s->private;
1255         struct trace_array *tr = iter->tr;
1256
1257         if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
1258                 return;
1259
1260         if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) {
1261                 /* print nothing if the buffers are empty */
1262                 if (trace_empty(iter))
1263                         return;
1264
1265                 print_trace_header(s, iter);
1266         }
1267
1268         __print_graph_headers_flags(tr, s, flags);
1269 }
1270
1271 void graph_trace_open(struct trace_iterator *iter)
1272 {
1273         /* pid and depth on the last trace processed */
1274         struct fgraph_data *data;
1275         gfp_t gfpflags;
1276         int cpu;
1277
1278         iter->private = NULL;
1279
1280         /* We can be called in atomic context via ftrace_dump() */
1281         gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
1282
1283         data = kzalloc(sizeof(*data), gfpflags);
1284         if (!data)
1285                 goto out_err;
1286
1287         data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
1288         if (!data->cpu_data)
1289                 goto out_err_free;
1290
1291         for_each_possible_cpu(cpu) {
1292                 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
1293                 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
1294                 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
1295                 int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
1296
1297                 *pid = -1;
1298                 *depth = 0;
1299                 *ignore = 0;
1300                 *depth_irq = -1;
1301         }
1302
1303         iter->private = data;
1304
1305         return;
1306
1307  out_err_free:
1308         kfree(data);
1309  out_err:
1310         pr_warn("function graph tracer: not enough memory\n");
1311 }
1312
1313 void graph_trace_close(struct trace_iterator *iter)
1314 {
1315         struct fgraph_data *data = iter->private;
1316
1317         if (data) {
1318                 free_percpu(data->cpu_data);
1319                 kfree(data);
1320         }
1321 }
1322
1323 static int
1324 func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1325 {
1326         if (bit == TRACE_GRAPH_PRINT_IRQS)
1327                 ftrace_graph_skip_irqs = !set;
1328
1329         if (bit == TRACE_GRAPH_SLEEP_TIME)
1330                 ftrace_graph_sleep_time_control(set);
1331
1332         if (bit == TRACE_GRAPH_GRAPH_TIME)
1333                 ftrace_graph_graph_time_control(set);
1334
1335         return 0;
1336 }
1337
1338 static struct trace_event_functions graph_functions = {
1339         .trace          = print_graph_function_event,
1340 };
1341
1342 static struct trace_event graph_trace_entry_event = {
1343         .type           = TRACE_GRAPH_ENT,
1344         .funcs          = &graph_functions,
1345 };
1346
1347 static struct trace_event graph_trace_ret_event = {
1348         .type           = TRACE_GRAPH_RET,
1349         .funcs          = &graph_functions
1350 };
1351
1352 static struct tracer graph_trace __tracer_data = {
1353         .name           = "function_graph",
1354         .update_thresh  = graph_trace_update_thresh,
1355         .open           = graph_trace_open,
1356         .pipe_open      = graph_trace_open,
1357         .close          = graph_trace_close,
1358         .pipe_close     = graph_trace_close,
1359         .init           = graph_trace_init,
1360         .reset          = graph_trace_reset,
1361         .print_line     = print_graph_function,
1362         .print_header   = print_graph_headers,
1363         .flags          = &tracer_flags,
1364         .set_flag       = func_graph_set_flag,
1365 #ifdef CONFIG_FTRACE_SELFTEST
1366         .selftest       = trace_selftest_startup_function_graph,
1367 #endif
1368 };
1369
1370
1371 static ssize_t
1372 graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
1373                   loff_t *ppos)
1374 {
1375         unsigned long val;
1376         int ret;
1377
1378         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1379         if (ret)
1380                 return ret;
1381
1382         fgraph_max_depth = val;
1383
1384         *ppos += cnt;
1385
1386         return cnt;
1387 }
1388
1389 static ssize_t
1390 graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
1391                  loff_t *ppos)
1392 {
1393         char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
1394         int n;
1395
1396         n = sprintf(buf, "%d\n", fgraph_max_depth);
1397
1398         return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
1399 }
1400
1401 static const struct file_operations graph_depth_fops = {
1402         .open           = tracing_open_generic,
1403         .write          = graph_depth_write,
1404         .read           = graph_depth_read,
1405         .llseek         = generic_file_llseek,
1406 };
1407
1408 static __init int init_graph_tracefs(void)
1409 {
1410         int ret;
1411
1412         ret = tracing_init_dentry();
1413         if (ret)
1414                 return 0;
1415
1416         trace_create_file("max_graph_depth", TRACE_MODE_WRITE, NULL,
1417                           NULL, &graph_depth_fops);
1418
1419         return 0;
1420 }
1421 fs_initcall(init_graph_tracefs);
1422
1423 static __init int init_graph_trace(void)
1424 {
1425         max_bytes_for_cpu = snprintf(NULL, 0, "%u", nr_cpu_ids - 1);
1426
1427         if (!register_trace_event(&graph_trace_entry_event)) {
1428                 pr_warn("Warning: could not register graph trace events\n");
1429                 return 1;
1430         }
1431
1432         if (!register_trace_event(&graph_trace_ret_event)) {
1433                 pr_warn("Warning: could not register graph trace events\n");
1434                 return 1;
1435         }
1436
1437         return register_tracer(&graph_trace);
1438 }
1439
1440 core_initcall(init_graph_trace);