1 /* 2 * 3 * Function graph tracer. 4 * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com> 5 * Mostly borrowed from function tracer which 6 * is Copyright (c) Steven Rostedt <srostedt@redhat.com> 7 * 8 */ 9 #include <linux/debugfs.h> 10 #include <linux/uaccess.h> 11 #include <linux/ftrace.h> 12 #include <linux/slab.h> 13 #include <linux/fs.h> 14 15 #include "trace.h" 16 #include "trace_output.h" 17 18 struct fgraph_cpu_data { 19 pid_t last_pid; 20 int depth; 21 int ignore; 22 unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH]; 23 }; 24 25 struct fgraph_data { 26 struct fgraph_cpu_data *cpu_data; 27 28 /* Place to preserve last processed entry. */ 29 struct ftrace_graph_ent_entry ent; 30 struct ftrace_graph_ret_entry ret; 31 int failed; 32 int cpu; 33 }; 34 35 #define TRACE_GRAPH_INDENT 2 36 37 /* Flag options */ 38 #define TRACE_GRAPH_PRINT_OVERRUN 0x1 39 #define TRACE_GRAPH_PRINT_CPU 0x2 40 #define TRACE_GRAPH_PRINT_OVERHEAD 0x4 41 #define TRACE_GRAPH_PRINT_PROC 0x8 42 #define TRACE_GRAPH_PRINT_DURATION 0x10 43 #define TRACE_GRAPH_PRINT_ABS_TIME 0x20 44 45 static struct tracer_opt trace_opts[] = { 46 /* Display overruns? (for self-debug purpose) */ 47 { TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) }, 48 /* Display CPU ? */ 49 { TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) }, 50 /* Display Overhead ? */ 51 { TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) }, 52 /* Display proc name/pid */ 53 { TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) }, 54 /* Display duration of execution */ 55 { TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) }, 56 /* Display absolute time of an entry */ 57 { TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) }, 58 { } /* Empty entry */ 59 }; 60 61 static struct tracer_flags tracer_flags = { 62 /* Don't display overruns and proc by default */ 63 .val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD | 64 TRACE_GRAPH_PRINT_DURATION, 65 .opts = trace_opts 66 }; 67 68 static struct trace_array *graph_array; 69 70 71 /* Add a function return address to the trace stack on thread info.*/ 72 int 73 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, 74 unsigned long frame_pointer) 75 { 76 unsigned long long calltime; 77 int index; 78 79 if (!current->ret_stack) 80 return -EBUSY; 81 82 /* 83 * We must make sure the ret_stack is tested before we read 84 * anything else. 85 */ 86 smp_rmb(); 87 88 /* The return trace stack is full */ 89 if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) { 90 atomic_inc(¤t->trace_overrun); 91 return -EBUSY; 92 } 93 94 calltime = trace_clock_local(); 95 96 index = ++current->curr_ret_stack; 97 barrier(); 98 current->ret_stack[index].ret = ret; 99 current->ret_stack[index].func = func; 100 current->ret_stack[index].calltime = calltime; 101 current->ret_stack[index].subtime = 0; 102 current->ret_stack[index].fp = frame_pointer; 103 *depth = index; 104 105 return 0; 106 } 107 108 /* Retrieve a function return address to the trace stack on thread info.*/ 109 static void 110 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret, 111 unsigned long frame_pointer) 112 { 113 int index; 114 115 index = current->curr_ret_stack; 116 117 if (unlikely(index < 0)) { 118 ftrace_graph_stop(); 119 WARN_ON(1); 120 /* Might as well panic, otherwise we have no where to go */ 121 *ret = (unsigned long)panic; 122 return; 123 } 124 125 #ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST 126 /* 127 * The arch may choose to record the frame pointer used 128 * and check it here to make sure that it is what we expect it 129 * to be. If gcc does not set the place holder of the return 130 * address in the frame pointer, and does a copy instead, then 131 * the function graph trace will fail. This test detects this 132 * case. 133 * 134 * Currently, x86_32 with optimize for size (-Os) makes the latest 135 * gcc do the above. 136 */ 137 if (unlikely(current->ret_stack[index].fp != frame_pointer)) { 138 ftrace_graph_stop(); 139 WARN(1, "Bad frame pointer: expected %lx, received %lx\n" 140 " from func %ps return to %lx\n", 141 current->ret_stack[index].fp, 142 frame_pointer, 143 (void *)current->ret_stack[index].func, 144 current->ret_stack[index].ret); 145 *ret = (unsigned long)panic; 146 return; 147 } 148 #endif 149 150 *ret = current->ret_stack[index].ret; 151 trace->func = current->ret_stack[index].func; 152 trace->calltime = current->ret_stack[index].calltime; 153 trace->overrun = atomic_read(¤t->trace_overrun); 154 trace->depth = index; 155 } 156 157 /* 158 * Send the trace to the ring-buffer. 159 * @return the original return address. 160 */ 161 unsigned long ftrace_return_to_handler(unsigned long frame_pointer) 162 { 163 struct ftrace_graph_ret trace; 164 unsigned long ret; 165 166 ftrace_pop_return_trace(&trace, &ret, frame_pointer); 167 trace.rettime = trace_clock_local(); 168 ftrace_graph_return(&trace); 169 barrier(); 170 current->curr_ret_stack--; 171 172 if (unlikely(!ret)) { 173 ftrace_graph_stop(); 174 WARN_ON(1); 175 /* Might as well panic. What else to do? */ 176 ret = (unsigned long)panic; 177 } 178 179 return ret; 180 } 181 182 int __trace_graph_entry(struct trace_array *tr, 183 struct ftrace_graph_ent *trace, 184 unsigned long flags, 185 int pc) 186 { 187 struct ftrace_event_call *call = &event_funcgraph_entry; 188 struct ring_buffer_event *event; 189 struct ring_buffer *buffer = tr->buffer; 190 struct ftrace_graph_ent_entry *entry; 191 192 if (unlikely(__this_cpu_read(ftrace_cpu_disabled))) 193 return 0; 194 195 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT, 196 sizeof(*entry), flags, pc); 197 if (!event) 198 return 0; 199 entry = ring_buffer_event_data(event); 200 entry->graph_ent = *trace; 201 if (!filter_current_check_discard(buffer, call, entry, event)) 202 ring_buffer_unlock_commit(buffer, event); 203 204 return 1; 205 } 206 207 int trace_graph_entry(struct ftrace_graph_ent *trace) 208 { 209 struct trace_array *tr = graph_array; 210 struct trace_array_cpu *data; 211 unsigned long flags; 212 long disabled; 213 int ret; 214 int cpu; 215 int pc; 216 217 if (!ftrace_trace_task(current)) 218 return 0; 219 220 /* trace it when it is-nested-in or is a function enabled. */ 221 if (!(trace->depth || ftrace_graph_addr(trace->func))) 222 return 0; 223 224 local_irq_save(flags); 225 cpu = raw_smp_processor_id(); 226 data = tr->data[cpu]; 227 disabled = atomic_inc_return(&data->disabled); 228 if (likely(disabled == 1)) { 229 pc = preempt_count(); 230 ret = __trace_graph_entry(tr, trace, flags, pc); 231 } else { 232 ret = 0; 233 } 234 235 atomic_dec(&data->disabled); 236 local_irq_restore(flags); 237 238 return ret; 239 } 240 241 int trace_graph_thresh_entry(struct ftrace_graph_ent *trace) 242 { 243 if (tracing_thresh) 244 return 1; 245 else 246 return trace_graph_entry(trace); 247 } 248 249 void __trace_graph_return(struct trace_array *tr, 250 struct ftrace_graph_ret *trace, 251 unsigned long flags, 252 int pc) 253 { 254 struct ftrace_event_call *call = &event_funcgraph_exit; 255 struct ring_buffer_event *event; 256 struct ring_buffer *buffer = tr->buffer; 257 struct ftrace_graph_ret_entry *entry; 258 259 if (unlikely(__this_cpu_read(ftrace_cpu_disabled))) 260 return; 261 262 event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET, 263 sizeof(*entry), flags, pc); 264 if (!event) 265 return; 266 entry = ring_buffer_event_data(event); 267 entry->ret = *trace; 268 if (!filter_current_check_discard(buffer, call, entry, event)) 269 ring_buffer_unlock_commit(buffer, event); 270 } 271 272 void trace_graph_return(struct ftrace_graph_ret *trace) 273 { 274 struct trace_array *tr = graph_array; 275 struct trace_array_cpu *data; 276 unsigned long flags; 277 long disabled; 278 int cpu; 279 int pc; 280 281 local_irq_save(flags); 282 cpu = raw_smp_processor_id(); 283 data = tr->data[cpu]; 284 disabled = atomic_inc_return(&data->disabled); 285 if (likely(disabled == 1)) { 286 pc = preempt_count(); 287 __trace_graph_return(tr, trace, flags, pc); 288 } 289 atomic_dec(&data->disabled); 290 local_irq_restore(flags); 291 } 292 293 void set_graph_array(struct trace_array *tr) 294 { 295 graph_array = tr; 296 297 /* Make graph_array visible before we start tracing */ 298 299 smp_mb(); 300 } 301 302 void trace_graph_thresh_return(struct ftrace_graph_ret *trace) 303 { 304 if (tracing_thresh && 305 (trace->rettime - trace->calltime < tracing_thresh)) 306 return; 307 else 308 trace_graph_return(trace); 309 } 310 311 static int graph_trace_init(struct trace_array *tr) 312 { 313 int ret; 314 315 set_graph_array(tr); 316 if (tracing_thresh) 317 ret = register_ftrace_graph(&trace_graph_thresh_return, 318 &trace_graph_thresh_entry); 319 else 320 ret = register_ftrace_graph(&trace_graph_return, 321 &trace_graph_entry); 322 if (ret) 323 return ret; 324 tracing_start_cmdline_record(); 325 326 return 0; 327 } 328 329 static void graph_trace_reset(struct trace_array *tr) 330 { 331 tracing_stop_cmdline_record(); 332 unregister_ftrace_graph(); 333 } 334 335 static int max_bytes_for_cpu; 336 337 static enum print_line_t 338 print_graph_cpu(struct trace_seq *s, int cpu) 339 { 340 int ret; 341 342 /* 343 * Start with a space character - to make it stand out 344 * to the right a bit when trace output is pasted into 345 * email: 346 */ 347 ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu); 348 if (!ret) 349 return TRACE_TYPE_PARTIAL_LINE; 350 351 return TRACE_TYPE_HANDLED; 352 } 353 354 #define TRACE_GRAPH_PROCINFO_LENGTH 14 355 356 static enum print_line_t 357 print_graph_proc(struct trace_seq *s, pid_t pid) 358 { 359 char comm[TASK_COMM_LEN]; 360 /* sign + log10(MAX_INT) + '\0' */ 361 char pid_str[11]; 362 int spaces = 0; 363 int ret; 364 int len; 365 int i; 366 367 trace_find_cmdline(pid, comm); 368 comm[7] = '\0'; 369 sprintf(pid_str, "%d", pid); 370 371 /* 1 stands for the "-" character */ 372 len = strlen(comm) + strlen(pid_str) + 1; 373 374 if (len < TRACE_GRAPH_PROCINFO_LENGTH) 375 spaces = TRACE_GRAPH_PROCINFO_LENGTH - len; 376 377 /* First spaces to align center */ 378 for (i = 0; i < spaces / 2; i++) { 379 ret = trace_seq_printf(s, " "); 380 if (!ret) 381 return TRACE_TYPE_PARTIAL_LINE; 382 } 383 384 ret = trace_seq_printf(s, "%s-%s", comm, pid_str); 385 if (!ret) 386 return TRACE_TYPE_PARTIAL_LINE; 387 388 /* Last spaces to align center */ 389 for (i = 0; i < spaces - (spaces / 2); i++) { 390 ret = trace_seq_printf(s, " "); 391 if (!ret) 392 return TRACE_TYPE_PARTIAL_LINE; 393 } 394 return TRACE_TYPE_HANDLED; 395 } 396 397 398 static enum print_line_t 399 print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry) 400 { 401 if (!trace_seq_putc(s, ' ')) 402 return 0; 403 404 return trace_print_lat_fmt(s, entry); 405 } 406 407 /* If the pid changed since the last trace, output this event */ 408 static enum print_line_t 409 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data) 410 { 411 pid_t prev_pid; 412 pid_t *last_pid; 413 int ret; 414 415 if (!data) 416 return TRACE_TYPE_HANDLED; 417 418 last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid); 419 420 if (*last_pid == pid) 421 return TRACE_TYPE_HANDLED; 422 423 prev_pid = *last_pid; 424 *last_pid = pid; 425 426 if (prev_pid == -1) 427 return TRACE_TYPE_HANDLED; 428 /* 429 * Context-switch trace line: 430 431 ------------------------------------------ 432 | 1) migration/0--1 => sshd-1755 433 ------------------------------------------ 434 435 */ 436 ret = trace_seq_printf(s, 437 " ------------------------------------------\n"); 438 if (!ret) 439 return TRACE_TYPE_PARTIAL_LINE; 440 441 ret = print_graph_cpu(s, cpu); 442 if (ret == TRACE_TYPE_PARTIAL_LINE) 443 return TRACE_TYPE_PARTIAL_LINE; 444 445 ret = print_graph_proc(s, prev_pid); 446 if (ret == TRACE_TYPE_PARTIAL_LINE) 447 return TRACE_TYPE_PARTIAL_LINE; 448 449 ret = trace_seq_printf(s, " => "); 450 if (!ret) 451 return TRACE_TYPE_PARTIAL_LINE; 452 453 ret = print_graph_proc(s, pid); 454 if (ret == TRACE_TYPE_PARTIAL_LINE) 455 return TRACE_TYPE_PARTIAL_LINE; 456 457 ret = trace_seq_printf(s, 458 "\n ------------------------------------------\n\n"); 459 if (!ret) 460 return TRACE_TYPE_PARTIAL_LINE; 461 462 return TRACE_TYPE_HANDLED; 463 } 464 465 static struct ftrace_graph_ret_entry * 466 get_return_for_leaf(struct trace_iterator *iter, 467 struct ftrace_graph_ent_entry *curr) 468 { 469 struct fgraph_data *data = iter->private; 470 struct ring_buffer_iter *ring_iter = NULL; 471 struct ring_buffer_event *event; 472 struct ftrace_graph_ret_entry *next; 473 474 /* 475 * If the previous output failed to write to the seq buffer, 476 * then we just reuse the data from before. 477 */ 478 if (data && data->failed) { 479 curr = &data->ent; 480 next = &data->ret; 481 } else { 482 483 ring_iter = iter->buffer_iter[iter->cpu]; 484 485 /* First peek to compare current entry and the next one */ 486 if (ring_iter) 487 event = ring_buffer_iter_peek(ring_iter, NULL); 488 else { 489 /* 490 * We need to consume the current entry to see 491 * the next one. 492 */ 493 ring_buffer_consume(iter->tr->buffer, iter->cpu, 494 NULL, NULL); 495 event = ring_buffer_peek(iter->tr->buffer, iter->cpu, 496 NULL, NULL); 497 } 498 499 if (!event) 500 return NULL; 501 502 next = ring_buffer_event_data(event); 503 504 if (data) { 505 /* 506 * Save current and next entries for later reference 507 * if the output fails. 508 */ 509 data->ent = *curr; 510 data->ret = *next; 511 } 512 } 513 514 if (next->ent.type != TRACE_GRAPH_RET) 515 return NULL; 516 517 if (curr->ent.pid != next->ent.pid || 518 curr->graph_ent.func != next->ret.func) 519 return NULL; 520 521 /* this is a leaf, now advance the iterator */ 522 if (ring_iter) 523 ring_buffer_read(ring_iter, NULL); 524 525 return next; 526 } 527 528 /* Signal a overhead of time execution to the output */ 529 static int 530 print_graph_overhead(unsigned long long duration, struct trace_seq *s, 531 u32 flags) 532 { 533 /* If duration disappear, we don't need anything */ 534 if (!(flags & TRACE_GRAPH_PRINT_DURATION)) 535 return 1; 536 537 /* Non nested entry or return */ 538 if (duration == -1) 539 return trace_seq_printf(s, " "); 540 541 if (flags & TRACE_GRAPH_PRINT_OVERHEAD) { 542 /* Duration exceeded 100 msecs */ 543 if (duration > 100000ULL) 544 return trace_seq_printf(s, "! "); 545 546 /* Duration exceeded 10 msecs */ 547 if (duration > 10000ULL) 548 return trace_seq_printf(s, "+ "); 549 } 550 551 return trace_seq_printf(s, " "); 552 } 553 554 static int print_graph_abs_time(u64 t, struct trace_seq *s) 555 { 556 unsigned long usecs_rem; 557 558 usecs_rem = do_div(t, NSEC_PER_SEC); 559 usecs_rem /= 1000; 560 561 return trace_seq_printf(s, "%5lu.%06lu | ", 562 (unsigned long)t, usecs_rem); 563 } 564 565 static enum print_line_t 566 print_graph_irq(struct trace_iterator *iter, unsigned long addr, 567 enum trace_type type, int cpu, pid_t pid, u32 flags) 568 { 569 int ret; 570 struct trace_seq *s = &iter->seq; 571 572 if (addr < (unsigned long)__irqentry_text_start || 573 addr >= (unsigned long)__irqentry_text_end) 574 return TRACE_TYPE_UNHANDLED; 575 576 /* Absolute time */ 577 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) { 578 ret = print_graph_abs_time(iter->ts, s); 579 if (!ret) 580 return TRACE_TYPE_PARTIAL_LINE; 581 } 582 583 /* Cpu */ 584 if (flags & TRACE_GRAPH_PRINT_CPU) { 585 ret = print_graph_cpu(s, cpu); 586 if (ret == TRACE_TYPE_PARTIAL_LINE) 587 return TRACE_TYPE_PARTIAL_LINE; 588 } 589 590 /* Proc */ 591 if (flags & TRACE_GRAPH_PRINT_PROC) { 592 ret = print_graph_proc(s, pid); 593 if (ret == TRACE_TYPE_PARTIAL_LINE) 594 return TRACE_TYPE_PARTIAL_LINE; 595 ret = trace_seq_printf(s, " | "); 596 if (!ret) 597 return TRACE_TYPE_PARTIAL_LINE; 598 } 599 600 /* No overhead */ 601 ret = print_graph_overhead(-1, s, flags); 602 if (!ret) 603 return TRACE_TYPE_PARTIAL_LINE; 604 605 if (type == TRACE_GRAPH_ENT) 606 ret = trace_seq_printf(s, "==========>"); 607 else 608 ret = trace_seq_printf(s, "<=========="); 609 610 if (!ret) 611 return TRACE_TYPE_PARTIAL_LINE; 612 613 /* Don't close the duration column if haven't one */ 614 if (flags & TRACE_GRAPH_PRINT_DURATION) 615 trace_seq_printf(s, " |"); 616 ret = trace_seq_printf(s, "\n"); 617 618 if (!ret) 619 return TRACE_TYPE_PARTIAL_LINE; 620 return TRACE_TYPE_HANDLED; 621 } 622 623 enum print_line_t 624 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s) 625 { 626 unsigned long nsecs_rem = do_div(duration, 1000); 627 /* log10(ULONG_MAX) + '\0' */ 628 char msecs_str[21]; 629 char nsecs_str[5]; 630 int ret, len; 631 int i; 632 633 sprintf(msecs_str, "%lu", (unsigned long) duration); 634 635 /* Print msecs */ 636 ret = trace_seq_printf(s, "%s", msecs_str); 637 if (!ret) 638 return TRACE_TYPE_PARTIAL_LINE; 639 640 len = strlen(msecs_str); 641 642 /* Print nsecs (we don't want to exceed 7 numbers) */ 643 if (len < 7) { 644 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem); 645 ret = trace_seq_printf(s, ".%s", nsecs_str); 646 if (!ret) 647 return TRACE_TYPE_PARTIAL_LINE; 648 len += strlen(nsecs_str); 649 } 650 651 ret = trace_seq_printf(s, " us "); 652 if (!ret) 653 return TRACE_TYPE_PARTIAL_LINE; 654 655 /* Print remaining spaces to fit the row's width */ 656 for (i = len; i < 7; i++) { 657 ret = trace_seq_printf(s, " "); 658 if (!ret) 659 return TRACE_TYPE_PARTIAL_LINE; 660 } 661 return TRACE_TYPE_HANDLED; 662 } 663 664 static enum print_line_t 665 print_graph_duration(unsigned long long duration, struct trace_seq *s) 666 { 667 int ret; 668 669 ret = trace_print_graph_duration(duration, s); 670 if (ret != TRACE_TYPE_HANDLED) 671 return ret; 672 673 ret = trace_seq_printf(s, "| "); 674 if (!ret) 675 return TRACE_TYPE_PARTIAL_LINE; 676 677 return TRACE_TYPE_HANDLED; 678 } 679 680 /* Case of a leaf function on its call entry */ 681 static enum print_line_t 682 print_graph_entry_leaf(struct trace_iterator *iter, 683 struct ftrace_graph_ent_entry *entry, 684 struct ftrace_graph_ret_entry *ret_entry, 685 struct trace_seq *s, u32 flags) 686 { 687 struct fgraph_data *data = iter->private; 688 struct ftrace_graph_ret *graph_ret; 689 struct ftrace_graph_ent *call; 690 unsigned long long duration; 691 int ret; 692 int i; 693 694 graph_ret = &ret_entry->ret; 695 call = &entry->graph_ent; 696 duration = graph_ret->rettime - graph_ret->calltime; 697 698 if (data) { 699 struct fgraph_cpu_data *cpu_data; 700 int cpu = iter->cpu; 701 702 cpu_data = per_cpu_ptr(data->cpu_data, cpu); 703 704 /* 705 * Comments display at + 1 to depth. Since 706 * this is a leaf function, keep the comments 707 * equal to this depth. 708 */ 709 cpu_data->depth = call->depth - 1; 710 711 /* No need to keep this function around for this depth */ 712 if (call->depth < FTRACE_RETFUNC_DEPTH) 713 cpu_data->enter_funcs[call->depth] = 0; 714 } 715 716 /* Overhead */ 717 ret = print_graph_overhead(duration, s, flags); 718 if (!ret) 719 return TRACE_TYPE_PARTIAL_LINE; 720 721 /* Duration */ 722 if (flags & TRACE_GRAPH_PRINT_DURATION) { 723 ret = print_graph_duration(duration, s); 724 if (ret == TRACE_TYPE_PARTIAL_LINE) 725 return TRACE_TYPE_PARTIAL_LINE; 726 } 727 728 /* Function */ 729 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) { 730 ret = trace_seq_printf(s, " "); 731 if (!ret) 732 return TRACE_TYPE_PARTIAL_LINE; 733 } 734 735 ret = trace_seq_printf(s, "%ps();\n", (void *)call->func); 736 if (!ret) 737 return TRACE_TYPE_PARTIAL_LINE; 738 739 return TRACE_TYPE_HANDLED; 740 } 741 742 static enum print_line_t 743 print_graph_entry_nested(struct trace_iterator *iter, 744 struct ftrace_graph_ent_entry *entry, 745 struct trace_seq *s, int cpu, u32 flags) 746 { 747 struct ftrace_graph_ent *call = &entry->graph_ent; 748 struct fgraph_data *data = iter->private; 749 int ret; 750 int i; 751 752 if (data) { 753 struct fgraph_cpu_data *cpu_data; 754 int cpu = iter->cpu; 755 756 cpu_data = per_cpu_ptr(data->cpu_data, cpu); 757 cpu_data->depth = call->depth; 758 759 /* Save this function pointer to see if the exit matches */ 760 if (call->depth < FTRACE_RETFUNC_DEPTH) 761 cpu_data->enter_funcs[call->depth] = call->func; 762 } 763 764 /* No overhead */ 765 ret = print_graph_overhead(-1, s, flags); 766 if (!ret) 767 return TRACE_TYPE_PARTIAL_LINE; 768 769 /* No time */ 770 if (flags & TRACE_GRAPH_PRINT_DURATION) { 771 ret = trace_seq_printf(s, " | "); 772 if (!ret) 773 return TRACE_TYPE_PARTIAL_LINE; 774 } 775 776 /* Function */ 777 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) { 778 ret = trace_seq_printf(s, " "); 779 if (!ret) 780 return TRACE_TYPE_PARTIAL_LINE; 781 } 782 783 ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func); 784 if (!ret) 785 return TRACE_TYPE_PARTIAL_LINE; 786 787 /* 788 * we already consumed the current entry to check the next one 789 * and see if this is a leaf. 790 */ 791 return TRACE_TYPE_NO_CONSUME; 792 } 793 794 static enum print_line_t 795 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s, 796 int type, unsigned long addr, u32 flags) 797 { 798 struct fgraph_data *data = iter->private; 799 struct trace_entry *ent = iter->ent; 800 int cpu = iter->cpu; 801 int ret; 802 803 /* Pid */ 804 if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE) 805 return TRACE_TYPE_PARTIAL_LINE; 806 807 if (type) { 808 /* Interrupt */ 809 ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags); 810 if (ret == TRACE_TYPE_PARTIAL_LINE) 811 return TRACE_TYPE_PARTIAL_LINE; 812 } 813 814 /* Absolute time */ 815 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) { 816 ret = print_graph_abs_time(iter->ts, s); 817 if (!ret) 818 return TRACE_TYPE_PARTIAL_LINE; 819 } 820 821 /* Cpu */ 822 if (flags & TRACE_GRAPH_PRINT_CPU) { 823 ret = print_graph_cpu(s, cpu); 824 if (ret == TRACE_TYPE_PARTIAL_LINE) 825 return TRACE_TYPE_PARTIAL_LINE; 826 } 827 828 /* Proc */ 829 if (flags & TRACE_GRAPH_PRINT_PROC) { 830 ret = print_graph_proc(s, ent->pid); 831 if (ret == TRACE_TYPE_PARTIAL_LINE) 832 return TRACE_TYPE_PARTIAL_LINE; 833 834 ret = trace_seq_printf(s, " | "); 835 if (!ret) 836 return TRACE_TYPE_PARTIAL_LINE; 837 } 838 839 /* Latency format */ 840 if (trace_flags & TRACE_ITER_LATENCY_FMT) { 841 ret = print_graph_lat_fmt(s, ent); 842 if (ret == TRACE_TYPE_PARTIAL_LINE) 843 return TRACE_TYPE_PARTIAL_LINE; 844 } 845 846 return 0; 847 } 848 849 static enum print_line_t 850 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s, 851 struct trace_iterator *iter, u32 flags) 852 { 853 struct fgraph_data *data = iter->private; 854 struct ftrace_graph_ent *call = &field->graph_ent; 855 struct ftrace_graph_ret_entry *leaf_ret; 856 static enum print_line_t ret; 857 int cpu = iter->cpu; 858 859 if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags)) 860 return TRACE_TYPE_PARTIAL_LINE; 861 862 leaf_ret = get_return_for_leaf(iter, field); 863 if (leaf_ret) 864 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags); 865 else 866 ret = print_graph_entry_nested(iter, field, s, cpu, flags); 867 868 if (data) { 869 /* 870 * If we failed to write our output, then we need to make 871 * note of it. Because we already consumed our entry. 872 */ 873 if (s->full) { 874 data->failed = 1; 875 data->cpu = cpu; 876 } else 877 data->failed = 0; 878 } 879 880 return ret; 881 } 882 883 static enum print_line_t 884 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, 885 struct trace_entry *ent, struct trace_iterator *iter, 886 u32 flags) 887 { 888 unsigned long long duration = trace->rettime - trace->calltime; 889 struct fgraph_data *data = iter->private; 890 pid_t pid = ent->pid; 891 int cpu = iter->cpu; 892 int func_match = 1; 893 int ret; 894 int i; 895 896 if (data) { 897 struct fgraph_cpu_data *cpu_data; 898 int cpu = iter->cpu; 899 900 cpu_data = per_cpu_ptr(data->cpu_data, cpu); 901 902 /* 903 * Comments display at + 1 to depth. This is the 904 * return from a function, we now want the comments 905 * to display at the same level of the bracket. 906 */ 907 cpu_data->depth = trace->depth - 1; 908 909 if (trace->depth < FTRACE_RETFUNC_DEPTH) { 910 if (cpu_data->enter_funcs[trace->depth] != trace->func) 911 func_match = 0; 912 cpu_data->enter_funcs[trace->depth] = 0; 913 } 914 } 915 916 if (print_graph_prologue(iter, s, 0, 0, flags)) 917 return TRACE_TYPE_PARTIAL_LINE; 918 919 /* Overhead */ 920 ret = print_graph_overhead(duration, s, flags); 921 if (!ret) 922 return TRACE_TYPE_PARTIAL_LINE; 923 924 /* Duration */ 925 if (flags & TRACE_GRAPH_PRINT_DURATION) { 926 ret = print_graph_duration(duration, s); 927 if (ret == TRACE_TYPE_PARTIAL_LINE) 928 return TRACE_TYPE_PARTIAL_LINE; 929 } 930 931 /* Closing brace */ 932 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) { 933 ret = trace_seq_printf(s, " "); 934 if (!ret) 935 return TRACE_TYPE_PARTIAL_LINE; 936 } 937 938 /* 939 * If the return function does not have a matching entry, 940 * then the entry was lost. Instead of just printing 941 * the '}' and letting the user guess what function this 942 * belongs to, write out the function name. 943 */ 944 if (func_match) { 945 ret = trace_seq_printf(s, "}\n"); 946 if (!ret) 947 return TRACE_TYPE_PARTIAL_LINE; 948 } else { 949 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func); 950 if (!ret) 951 return TRACE_TYPE_PARTIAL_LINE; 952 } 953 954 /* Overrun */ 955 if (flags & TRACE_GRAPH_PRINT_OVERRUN) { 956 ret = trace_seq_printf(s, " (Overruns: %lu)\n", 957 trace->overrun); 958 if (!ret) 959 return TRACE_TYPE_PARTIAL_LINE; 960 } 961 962 ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, 963 cpu, pid, flags); 964 if (ret == TRACE_TYPE_PARTIAL_LINE) 965 return TRACE_TYPE_PARTIAL_LINE; 966 967 return TRACE_TYPE_HANDLED; 968 } 969 970 static enum print_line_t 971 print_graph_comment(struct trace_seq *s, struct trace_entry *ent, 972 struct trace_iterator *iter, u32 flags) 973 { 974 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK); 975 struct fgraph_data *data = iter->private; 976 struct trace_event *event; 977 int depth = 0; 978 int ret; 979 int i; 980 981 if (data) 982 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth; 983 984 if (print_graph_prologue(iter, s, 0, 0, flags)) 985 return TRACE_TYPE_PARTIAL_LINE; 986 987 /* No overhead */ 988 ret = print_graph_overhead(-1, s, flags); 989 if (!ret) 990 return TRACE_TYPE_PARTIAL_LINE; 991 992 /* No time */ 993 if (flags & TRACE_GRAPH_PRINT_DURATION) { 994 ret = trace_seq_printf(s, " | "); 995 if (!ret) 996 return TRACE_TYPE_PARTIAL_LINE; 997 } 998 999 /* Indentation */ 1000 if (depth > 0) 1001 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) { 1002 ret = trace_seq_printf(s, " "); 1003 if (!ret) 1004 return TRACE_TYPE_PARTIAL_LINE; 1005 } 1006 1007 /* The comment */ 1008 ret = trace_seq_printf(s, "/* "); 1009 if (!ret) 1010 return TRACE_TYPE_PARTIAL_LINE; 1011 1012 switch (iter->ent->type) { 1013 case TRACE_BPRINT: 1014 ret = trace_print_bprintk_msg_only(iter); 1015 if (ret != TRACE_TYPE_HANDLED) 1016 return ret; 1017 break; 1018 case TRACE_PRINT: 1019 ret = trace_print_printk_msg_only(iter); 1020 if (ret != TRACE_TYPE_HANDLED) 1021 return ret; 1022 break; 1023 default: 1024 event = ftrace_find_event(ent->type); 1025 if (!event) 1026 return TRACE_TYPE_UNHANDLED; 1027 1028 ret = event->trace(iter, sym_flags); 1029 if (ret != TRACE_TYPE_HANDLED) 1030 return ret; 1031 } 1032 1033 /* Strip ending newline */ 1034 if (s->buffer[s->len - 1] == '\n') { 1035 s->buffer[s->len - 1] = '\0'; 1036 s->len--; 1037 } 1038 1039 ret = trace_seq_printf(s, " */\n"); 1040 if (!ret) 1041 return TRACE_TYPE_PARTIAL_LINE; 1042 1043 return TRACE_TYPE_HANDLED; 1044 } 1045 1046 1047 enum print_line_t 1048 print_graph_function_flags(struct trace_iterator *iter, u32 flags) 1049 { 1050 struct ftrace_graph_ent_entry *field; 1051 struct fgraph_data *data = iter->private; 1052 struct trace_entry *entry = iter->ent; 1053 struct trace_seq *s = &iter->seq; 1054 int cpu = iter->cpu; 1055 int ret; 1056 1057 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) { 1058 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0; 1059 return TRACE_TYPE_HANDLED; 1060 } 1061 1062 /* 1063 * If the last output failed, there's a possibility we need 1064 * to print out the missing entry which would never go out. 1065 */ 1066 if (data && data->failed) { 1067 field = &data->ent; 1068 iter->cpu = data->cpu; 1069 ret = print_graph_entry(field, s, iter, flags); 1070 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) { 1071 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1; 1072 ret = TRACE_TYPE_NO_CONSUME; 1073 } 1074 iter->cpu = cpu; 1075 return ret; 1076 } 1077 1078 switch (entry->type) { 1079 case TRACE_GRAPH_ENT: { 1080 /* 1081 * print_graph_entry() may consume the current event, 1082 * thus @field may become invalid, so we need to save it. 1083 * sizeof(struct ftrace_graph_ent_entry) is very small, 1084 * it can be safely saved at the stack. 1085 */ 1086 struct ftrace_graph_ent_entry saved; 1087 trace_assign_type(field, entry); 1088 saved = *field; 1089 return print_graph_entry(&saved, s, iter, flags); 1090 } 1091 case TRACE_GRAPH_RET: { 1092 struct ftrace_graph_ret_entry *field; 1093 trace_assign_type(field, entry); 1094 return print_graph_return(&field->ret, s, entry, iter, flags); 1095 } 1096 case TRACE_STACK: 1097 case TRACE_FN: 1098 /* dont trace stack and functions as comments */ 1099 return TRACE_TYPE_UNHANDLED; 1100 1101 default: 1102 return print_graph_comment(s, entry, iter, flags); 1103 } 1104 1105 return TRACE_TYPE_HANDLED; 1106 } 1107 1108 static enum print_line_t 1109 print_graph_function(struct trace_iterator *iter) 1110 { 1111 return print_graph_function_flags(iter, tracer_flags.val); 1112 } 1113 1114 static enum print_line_t 1115 print_graph_function_event(struct trace_iterator *iter, int flags) 1116 { 1117 return print_graph_function(iter); 1118 } 1119 1120 static void print_lat_header(struct seq_file *s, u32 flags) 1121 { 1122 static const char spaces[] = " " /* 16 spaces */ 1123 " " /* 4 spaces */ 1124 " "; /* 17 spaces */ 1125 int size = 0; 1126 1127 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) 1128 size += 16; 1129 if (flags & TRACE_GRAPH_PRINT_CPU) 1130 size += 4; 1131 if (flags & TRACE_GRAPH_PRINT_PROC) 1132 size += 17; 1133 1134 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces); 1135 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces); 1136 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces); 1137 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces); 1138 seq_printf(s, "#%.*s||| / _-=> lock-depth \n", size, spaces); 1139 seq_printf(s, "#%.*s|||| / \n", size, spaces); 1140 } 1141 1142 void print_graph_headers_flags(struct seq_file *s, u32 flags) 1143 { 1144 int lat = trace_flags & TRACE_ITER_LATENCY_FMT; 1145 1146 if (lat) 1147 print_lat_header(s, flags); 1148 1149 /* 1st line */ 1150 seq_printf(s, "#"); 1151 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) 1152 seq_printf(s, " TIME "); 1153 if (flags & TRACE_GRAPH_PRINT_CPU) 1154 seq_printf(s, " CPU"); 1155 if (flags & TRACE_GRAPH_PRINT_PROC) 1156 seq_printf(s, " TASK/PID "); 1157 if (lat) 1158 seq_printf(s, "|||||"); 1159 if (flags & TRACE_GRAPH_PRINT_DURATION) 1160 seq_printf(s, " DURATION "); 1161 seq_printf(s, " FUNCTION CALLS\n"); 1162 1163 /* 2nd line */ 1164 seq_printf(s, "#"); 1165 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) 1166 seq_printf(s, " | "); 1167 if (flags & TRACE_GRAPH_PRINT_CPU) 1168 seq_printf(s, " | "); 1169 if (flags & TRACE_GRAPH_PRINT_PROC) 1170 seq_printf(s, " | | "); 1171 if (lat) 1172 seq_printf(s, "|||||"); 1173 if (flags & TRACE_GRAPH_PRINT_DURATION) 1174 seq_printf(s, " | | "); 1175 seq_printf(s, " | | | |\n"); 1176 } 1177 1178 void print_graph_headers(struct seq_file *s) 1179 { 1180 print_graph_headers_flags(s, tracer_flags.val); 1181 } 1182 1183 void graph_trace_open(struct trace_iterator *iter) 1184 { 1185 /* pid and depth on the last trace processed */ 1186 struct fgraph_data *data; 1187 int cpu; 1188 1189 iter->private = NULL; 1190 1191 data = kzalloc(sizeof(*data), GFP_KERNEL); 1192 if (!data) 1193 goto out_err; 1194 1195 data->cpu_data = alloc_percpu(struct fgraph_cpu_data); 1196 if (!data->cpu_data) 1197 goto out_err_free; 1198 1199 for_each_possible_cpu(cpu) { 1200 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid); 1201 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); 1202 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore); 1203 *pid = -1; 1204 *depth = 0; 1205 *ignore = 0; 1206 } 1207 1208 iter->private = data; 1209 1210 return; 1211 1212 out_err_free: 1213 kfree(data); 1214 out_err: 1215 pr_warning("function graph tracer: not enough memory\n"); 1216 } 1217 1218 void graph_trace_close(struct trace_iterator *iter) 1219 { 1220 struct fgraph_data *data = iter->private; 1221 1222 if (data) { 1223 free_percpu(data->cpu_data); 1224 kfree(data); 1225 } 1226 } 1227 1228 static struct trace_event graph_trace_entry_event = { 1229 .type = TRACE_GRAPH_ENT, 1230 .trace = print_graph_function_event, 1231 }; 1232 1233 static struct trace_event graph_trace_ret_event = { 1234 .type = TRACE_GRAPH_RET, 1235 .trace = print_graph_function_event, 1236 }; 1237 1238 static struct tracer graph_trace __read_mostly = { 1239 .name = "function_graph", 1240 .open = graph_trace_open, 1241 .pipe_open = graph_trace_open, 1242 .close = graph_trace_close, 1243 .pipe_close = graph_trace_close, 1244 .wait_pipe = poll_wait_pipe, 1245 .init = graph_trace_init, 1246 .reset = graph_trace_reset, 1247 .print_line = print_graph_function, 1248 .print_header = print_graph_headers, 1249 .flags = &tracer_flags, 1250 #ifdef CONFIG_FTRACE_SELFTEST 1251 .selftest = trace_selftest_startup_function_graph, 1252 #endif 1253 }; 1254 1255 static __init int init_graph_trace(void) 1256 { 1257 max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1); 1258 1259 if (!register_ftrace_event(&graph_trace_entry_event)) { 1260 pr_warning("Warning: could not register graph trace events\n"); 1261 return 1; 1262 } 1263 1264 if (!register_ftrace_event(&graph_trace_ret_event)) { 1265 pr_warning("Warning: could not register graph trace events\n"); 1266 return 1; 1267 } 1268 1269 return register_tracer(&graph_trace); 1270 } 1271 1272 device_initcall(init_graph_trace); 1273