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 /* 511 * If the next event is not a return type, then 512 * we only care about what type it is. Otherwise we can 513 * safely copy the entire event. 514 */ 515 if (next->ent.type == TRACE_GRAPH_RET) 516 data->ret = *next; 517 else 518 data->ret.ent.type = next->ent.type; 519 } 520 } 521 522 if (next->ent.type != TRACE_GRAPH_RET) 523 return NULL; 524 525 if (curr->ent.pid != next->ent.pid || 526 curr->graph_ent.func != next->ret.func) 527 return NULL; 528 529 /* this is a leaf, now advance the iterator */ 530 if (ring_iter) 531 ring_buffer_read(ring_iter, NULL); 532 533 return next; 534 } 535 536 /* Signal a overhead of time execution to the output */ 537 static int 538 print_graph_overhead(unsigned long long duration, struct trace_seq *s, 539 u32 flags) 540 { 541 /* If duration disappear, we don't need anything */ 542 if (!(flags & TRACE_GRAPH_PRINT_DURATION)) 543 return 1; 544 545 /* Non nested entry or return */ 546 if (duration == -1) 547 return trace_seq_printf(s, " "); 548 549 if (flags & TRACE_GRAPH_PRINT_OVERHEAD) { 550 /* Duration exceeded 100 msecs */ 551 if (duration > 100000ULL) 552 return trace_seq_printf(s, "! "); 553 554 /* Duration exceeded 10 msecs */ 555 if (duration > 10000ULL) 556 return trace_seq_printf(s, "+ "); 557 } 558 559 return trace_seq_printf(s, " "); 560 } 561 562 static int print_graph_abs_time(u64 t, struct trace_seq *s) 563 { 564 unsigned long usecs_rem; 565 566 usecs_rem = do_div(t, NSEC_PER_SEC); 567 usecs_rem /= 1000; 568 569 return trace_seq_printf(s, "%5lu.%06lu | ", 570 (unsigned long)t, usecs_rem); 571 } 572 573 static enum print_line_t 574 print_graph_irq(struct trace_iterator *iter, unsigned long addr, 575 enum trace_type type, int cpu, pid_t pid, u32 flags) 576 { 577 int ret; 578 struct trace_seq *s = &iter->seq; 579 580 if (addr < (unsigned long)__irqentry_text_start || 581 addr >= (unsigned long)__irqentry_text_end) 582 return TRACE_TYPE_UNHANDLED; 583 584 /* Absolute time */ 585 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) { 586 ret = print_graph_abs_time(iter->ts, s); 587 if (!ret) 588 return TRACE_TYPE_PARTIAL_LINE; 589 } 590 591 /* Cpu */ 592 if (flags & TRACE_GRAPH_PRINT_CPU) { 593 ret = print_graph_cpu(s, cpu); 594 if (ret == TRACE_TYPE_PARTIAL_LINE) 595 return TRACE_TYPE_PARTIAL_LINE; 596 } 597 598 /* Proc */ 599 if (flags & TRACE_GRAPH_PRINT_PROC) { 600 ret = print_graph_proc(s, pid); 601 if (ret == TRACE_TYPE_PARTIAL_LINE) 602 return TRACE_TYPE_PARTIAL_LINE; 603 ret = trace_seq_printf(s, " | "); 604 if (!ret) 605 return TRACE_TYPE_PARTIAL_LINE; 606 } 607 608 /* No overhead */ 609 ret = print_graph_overhead(-1, s, flags); 610 if (!ret) 611 return TRACE_TYPE_PARTIAL_LINE; 612 613 if (type == TRACE_GRAPH_ENT) 614 ret = trace_seq_printf(s, "==========>"); 615 else 616 ret = trace_seq_printf(s, "<=========="); 617 618 if (!ret) 619 return TRACE_TYPE_PARTIAL_LINE; 620 621 /* Don't close the duration column if haven't one */ 622 if (flags & TRACE_GRAPH_PRINT_DURATION) 623 trace_seq_printf(s, " |"); 624 ret = trace_seq_printf(s, "\n"); 625 626 if (!ret) 627 return TRACE_TYPE_PARTIAL_LINE; 628 return TRACE_TYPE_HANDLED; 629 } 630 631 enum print_line_t 632 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s) 633 { 634 unsigned long nsecs_rem = do_div(duration, 1000); 635 /* log10(ULONG_MAX) + '\0' */ 636 char msecs_str[21]; 637 char nsecs_str[5]; 638 int ret, len; 639 int i; 640 641 sprintf(msecs_str, "%lu", (unsigned long) duration); 642 643 /* Print msecs */ 644 ret = trace_seq_printf(s, "%s", msecs_str); 645 if (!ret) 646 return TRACE_TYPE_PARTIAL_LINE; 647 648 len = strlen(msecs_str); 649 650 /* Print nsecs (we don't want to exceed 7 numbers) */ 651 if (len < 7) { 652 snprintf(nsecs_str, min(sizeof(nsecs_str), 8UL - len), "%03lu", 653 nsecs_rem); 654 ret = trace_seq_printf(s, ".%s", nsecs_str); 655 if (!ret) 656 return TRACE_TYPE_PARTIAL_LINE; 657 len += strlen(nsecs_str); 658 } 659 660 ret = trace_seq_printf(s, " us "); 661 if (!ret) 662 return TRACE_TYPE_PARTIAL_LINE; 663 664 /* Print remaining spaces to fit the row's width */ 665 for (i = len; i < 7; i++) { 666 ret = trace_seq_printf(s, " "); 667 if (!ret) 668 return TRACE_TYPE_PARTIAL_LINE; 669 } 670 return TRACE_TYPE_HANDLED; 671 } 672 673 static enum print_line_t 674 print_graph_duration(unsigned long long duration, struct trace_seq *s) 675 { 676 int ret; 677 678 ret = trace_print_graph_duration(duration, s); 679 if (ret != TRACE_TYPE_HANDLED) 680 return ret; 681 682 ret = trace_seq_printf(s, "| "); 683 if (!ret) 684 return TRACE_TYPE_PARTIAL_LINE; 685 686 return TRACE_TYPE_HANDLED; 687 } 688 689 /* Case of a leaf function on its call entry */ 690 static enum print_line_t 691 print_graph_entry_leaf(struct trace_iterator *iter, 692 struct ftrace_graph_ent_entry *entry, 693 struct ftrace_graph_ret_entry *ret_entry, 694 struct trace_seq *s, u32 flags) 695 { 696 struct fgraph_data *data = iter->private; 697 struct ftrace_graph_ret *graph_ret; 698 struct ftrace_graph_ent *call; 699 unsigned long long duration; 700 int ret; 701 int i; 702 703 graph_ret = &ret_entry->ret; 704 call = &entry->graph_ent; 705 duration = graph_ret->rettime - graph_ret->calltime; 706 707 if (data) { 708 struct fgraph_cpu_data *cpu_data; 709 int cpu = iter->cpu; 710 711 cpu_data = per_cpu_ptr(data->cpu_data, cpu); 712 713 /* 714 * Comments display at + 1 to depth. Since 715 * this is a leaf function, keep the comments 716 * equal to this depth. 717 */ 718 cpu_data->depth = call->depth - 1; 719 720 /* No need to keep this function around for this depth */ 721 if (call->depth < FTRACE_RETFUNC_DEPTH) 722 cpu_data->enter_funcs[call->depth] = 0; 723 } 724 725 /* Overhead */ 726 ret = print_graph_overhead(duration, s, flags); 727 if (!ret) 728 return TRACE_TYPE_PARTIAL_LINE; 729 730 /* Duration */ 731 if (flags & TRACE_GRAPH_PRINT_DURATION) { 732 ret = print_graph_duration(duration, s); 733 if (ret == TRACE_TYPE_PARTIAL_LINE) 734 return TRACE_TYPE_PARTIAL_LINE; 735 } 736 737 /* Function */ 738 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) { 739 ret = trace_seq_printf(s, " "); 740 if (!ret) 741 return TRACE_TYPE_PARTIAL_LINE; 742 } 743 744 ret = trace_seq_printf(s, "%ps();\n", (void *)call->func); 745 if (!ret) 746 return TRACE_TYPE_PARTIAL_LINE; 747 748 return TRACE_TYPE_HANDLED; 749 } 750 751 static enum print_line_t 752 print_graph_entry_nested(struct trace_iterator *iter, 753 struct ftrace_graph_ent_entry *entry, 754 struct trace_seq *s, int cpu, u32 flags) 755 { 756 struct ftrace_graph_ent *call = &entry->graph_ent; 757 struct fgraph_data *data = iter->private; 758 int ret; 759 int i; 760 761 if (data) { 762 struct fgraph_cpu_data *cpu_data; 763 int cpu = iter->cpu; 764 765 cpu_data = per_cpu_ptr(data->cpu_data, cpu); 766 cpu_data->depth = call->depth; 767 768 /* Save this function pointer to see if the exit matches */ 769 if (call->depth < FTRACE_RETFUNC_DEPTH) 770 cpu_data->enter_funcs[call->depth] = call->func; 771 } 772 773 /* No overhead */ 774 ret = print_graph_overhead(-1, s, flags); 775 if (!ret) 776 return TRACE_TYPE_PARTIAL_LINE; 777 778 /* No time */ 779 if (flags & TRACE_GRAPH_PRINT_DURATION) { 780 ret = trace_seq_printf(s, " | "); 781 if (!ret) 782 return TRACE_TYPE_PARTIAL_LINE; 783 } 784 785 /* Function */ 786 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) { 787 ret = trace_seq_printf(s, " "); 788 if (!ret) 789 return TRACE_TYPE_PARTIAL_LINE; 790 } 791 792 ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func); 793 if (!ret) 794 return TRACE_TYPE_PARTIAL_LINE; 795 796 /* 797 * we already consumed the current entry to check the next one 798 * and see if this is a leaf. 799 */ 800 return TRACE_TYPE_NO_CONSUME; 801 } 802 803 static enum print_line_t 804 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s, 805 int type, unsigned long addr, u32 flags) 806 { 807 struct fgraph_data *data = iter->private; 808 struct trace_entry *ent = iter->ent; 809 int cpu = iter->cpu; 810 int ret; 811 812 /* Pid */ 813 if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE) 814 return TRACE_TYPE_PARTIAL_LINE; 815 816 if (type) { 817 /* Interrupt */ 818 ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags); 819 if (ret == TRACE_TYPE_PARTIAL_LINE) 820 return TRACE_TYPE_PARTIAL_LINE; 821 } 822 823 /* Absolute time */ 824 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) { 825 ret = print_graph_abs_time(iter->ts, s); 826 if (!ret) 827 return TRACE_TYPE_PARTIAL_LINE; 828 } 829 830 /* Cpu */ 831 if (flags & TRACE_GRAPH_PRINT_CPU) { 832 ret = print_graph_cpu(s, cpu); 833 if (ret == TRACE_TYPE_PARTIAL_LINE) 834 return TRACE_TYPE_PARTIAL_LINE; 835 } 836 837 /* Proc */ 838 if (flags & TRACE_GRAPH_PRINT_PROC) { 839 ret = print_graph_proc(s, ent->pid); 840 if (ret == TRACE_TYPE_PARTIAL_LINE) 841 return TRACE_TYPE_PARTIAL_LINE; 842 843 ret = trace_seq_printf(s, " | "); 844 if (!ret) 845 return TRACE_TYPE_PARTIAL_LINE; 846 } 847 848 /* Latency format */ 849 if (trace_flags & TRACE_ITER_LATENCY_FMT) { 850 ret = print_graph_lat_fmt(s, ent); 851 if (ret == TRACE_TYPE_PARTIAL_LINE) 852 return TRACE_TYPE_PARTIAL_LINE; 853 } 854 855 return 0; 856 } 857 858 static enum print_line_t 859 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s, 860 struct trace_iterator *iter, u32 flags) 861 { 862 struct fgraph_data *data = iter->private; 863 struct ftrace_graph_ent *call = &field->graph_ent; 864 struct ftrace_graph_ret_entry *leaf_ret; 865 static enum print_line_t ret; 866 int cpu = iter->cpu; 867 868 if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags)) 869 return TRACE_TYPE_PARTIAL_LINE; 870 871 leaf_ret = get_return_for_leaf(iter, field); 872 if (leaf_ret) 873 ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags); 874 else 875 ret = print_graph_entry_nested(iter, field, s, cpu, flags); 876 877 if (data) { 878 /* 879 * If we failed to write our output, then we need to make 880 * note of it. Because we already consumed our entry. 881 */ 882 if (s->full) { 883 data->failed = 1; 884 data->cpu = cpu; 885 } else 886 data->failed = 0; 887 } 888 889 return ret; 890 } 891 892 static enum print_line_t 893 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, 894 struct trace_entry *ent, struct trace_iterator *iter, 895 u32 flags) 896 { 897 unsigned long long duration = trace->rettime - trace->calltime; 898 struct fgraph_data *data = iter->private; 899 pid_t pid = ent->pid; 900 int cpu = iter->cpu; 901 int func_match = 1; 902 int ret; 903 int i; 904 905 if (data) { 906 struct fgraph_cpu_data *cpu_data; 907 int cpu = iter->cpu; 908 909 cpu_data = per_cpu_ptr(data->cpu_data, cpu); 910 911 /* 912 * Comments display at + 1 to depth. This is the 913 * return from a function, we now want the comments 914 * to display at the same level of the bracket. 915 */ 916 cpu_data->depth = trace->depth - 1; 917 918 if (trace->depth < FTRACE_RETFUNC_DEPTH) { 919 if (cpu_data->enter_funcs[trace->depth] != trace->func) 920 func_match = 0; 921 cpu_data->enter_funcs[trace->depth] = 0; 922 } 923 } 924 925 if (print_graph_prologue(iter, s, 0, 0, flags)) 926 return TRACE_TYPE_PARTIAL_LINE; 927 928 /* Overhead */ 929 ret = print_graph_overhead(duration, s, flags); 930 if (!ret) 931 return TRACE_TYPE_PARTIAL_LINE; 932 933 /* Duration */ 934 if (flags & TRACE_GRAPH_PRINT_DURATION) { 935 ret = print_graph_duration(duration, s); 936 if (ret == TRACE_TYPE_PARTIAL_LINE) 937 return TRACE_TYPE_PARTIAL_LINE; 938 } 939 940 /* Closing brace */ 941 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) { 942 ret = trace_seq_printf(s, " "); 943 if (!ret) 944 return TRACE_TYPE_PARTIAL_LINE; 945 } 946 947 /* 948 * If the return function does not have a matching entry, 949 * then the entry was lost. Instead of just printing 950 * the '}' and letting the user guess what function this 951 * belongs to, write out the function name. 952 */ 953 if (func_match) { 954 ret = trace_seq_printf(s, "}\n"); 955 if (!ret) 956 return TRACE_TYPE_PARTIAL_LINE; 957 } else { 958 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func); 959 if (!ret) 960 return TRACE_TYPE_PARTIAL_LINE; 961 } 962 963 /* Overrun */ 964 if (flags & TRACE_GRAPH_PRINT_OVERRUN) { 965 ret = trace_seq_printf(s, " (Overruns: %lu)\n", 966 trace->overrun); 967 if (!ret) 968 return TRACE_TYPE_PARTIAL_LINE; 969 } 970 971 ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, 972 cpu, pid, flags); 973 if (ret == TRACE_TYPE_PARTIAL_LINE) 974 return TRACE_TYPE_PARTIAL_LINE; 975 976 return TRACE_TYPE_HANDLED; 977 } 978 979 static enum print_line_t 980 print_graph_comment(struct trace_seq *s, struct trace_entry *ent, 981 struct trace_iterator *iter, u32 flags) 982 { 983 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK); 984 struct fgraph_data *data = iter->private; 985 struct trace_event *event; 986 int depth = 0; 987 int ret; 988 int i; 989 990 if (data) 991 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth; 992 993 if (print_graph_prologue(iter, s, 0, 0, flags)) 994 return TRACE_TYPE_PARTIAL_LINE; 995 996 /* No overhead */ 997 ret = print_graph_overhead(-1, s, flags); 998 if (!ret) 999 return TRACE_TYPE_PARTIAL_LINE; 1000 1001 /* No time */ 1002 if (flags & TRACE_GRAPH_PRINT_DURATION) { 1003 ret = trace_seq_printf(s, " | "); 1004 if (!ret) 1005 return TRACE_TYPE_PARTIAL_LINE; 1006 } 1007 1008 /* Indentation */ 1009 if (depth > 0) 1010 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) { 1011 ret = trace_seq_printf(s, " "); 1012 if (!ret) 1013 return TRACE_TYPE_PARTIAL_LINE; 1014 } 1015 1016 /* The comment */ 1017 ret = trace_seq_printf(s, "/* "); 1018 if (!ret) 1019 return TRACE_TYPE_PARTIAL_LINE; 1020 1021 switch (iter->ent->type) { 1022 case TRACE_BPRINT: 1023 ret = trace_print_bprintk_msg_only(iter); 1024 if (ret != TRACE_TYPE_HANDLED) 1025 return ret; 1026 break; 1027 case TRACE_PRINT: 1028 ret = trace_print_printk_msg_only(iter); 1029 if (ret != TRACE_TYPE_HANDLED) 1030 return ret; 1031 break; 1032 default: 1033 event = ftrace_find_event(ent->type); 1034 if (!event) 1035 return TRACE_TYPE_UNHANDLED; 1036 1037 ret = event->funcs->trace(iter, sym_flags, event); 1038 if (ret != TRACE_TYPE_HANDLED) 1039 return ret; 1040 } 1041 1042 /* Strip ending newline */ 1043 if (s->buffer[s->len - 1] == '\n') { 1044 s->buffer[s->len - 1] = '\0'; 1045 s->len--; 1046 } 1047 1048 ret = trace_seq_printf(s, " */\n"); 1049 if (!ret) 1050 return TRACE_TYPE_PARTIAL_LINE; 1051 1052 return TRACE_TYPE_HANDLED; 1053 } 1054 1055 1056 enum print_line_t 1057 print_graph_function_flags(struct trace_iterator *iter, u32 flags) 1058 { 1059 struct ftrace_graph_ent_entry *field; 1060 struct fgraph_data *data = iter->private; 1061 struct trace_entry *entry = iter->ent; 1062 struct trace_seq *s = &iter->seq; 1063 int cpu = iter->cpu; 1064 int ret; 1065 1066 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) { 1067 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0; 1068 return TRACE_TYPE_HANDLED; 1069 } 1070 1071 /* 1072 * If the last output failed, there's a possibility we need 1073 * to print out the missing entry which would never go out. 1074 */ 1075 if (data && data->failed) { 1076 field = &data->ent; 1077 iter->cpu = data->cpu; 1078 ret = print_graph_entry(field, s, iter, flags); 1079 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) { 1080 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1; 1081 ret = TRACE_TYPE_NO_CONSUME; 1082 } 1083 iter->cpu = cpu; 1084 return ret; 1085 } 1086 1087 switch (entry->type) { 1088 case TRACE_GRAPH_ENT: { 1089 /* 1090 * print_graph_entry() may consume the current event, 1091 * thus @field may become invalid, so we need to save it. 1092 * sizeof(struct ftrace_graph_ent_entry) is very small, 1093 * it can be safely saved at the stack. 1094 */ 1095 struct ftrace_graph_ent_entry saved; 1096 trace_assign_type(field, entry); 1097 saved = *field; 1098 return print_graph_entry(&saved, s, iter, flags); 1099 } 1100 case TRACE_GRAPH_RET: { 1101 struct ftrace_graph_ret_entry *field; 1102 trace_assign_type(field, entry); 1103 return print_graph_return(&field->ret, s, entry, iter, flags); 1104 } 1105 case TRACE_STACK: 1106 case TRACE_FN: 1107 /* dont trace stack and functions as comments */ 1108 return TRACE_TYPE_UNHANDLED; 1109 1110 default: 1111 return print_graph_comment(s, entry, iter, flags); 1112 } 1113 1114 return TRACE_TYPE_HANDLED; 1115 } 1116 1117 static enum print_line_t 1118 print_graph_function(struct trace_iterator *iter) 1119 { 1120 return print_graph_function_flags(iter, tracer_flags.val); 1121 } 1122 1123 static enum print_line_t 1124 print_graph_function_event(struct trace_iterator *iter, int flags, 1125 struct trace_event *event) 1126 { 1127 return print_graph_function(iter); 1128 } 1129 1130 static void print_lat_header(struct seq_file *s, u32 flags) 1131 { 1132 static const char spaces[] = " " /* 16 spaces */ 1133 " " /* 4 spaces */ 1134 " "; /* 17 spaces */ 1135 int size = 0; 1136 1137 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) 1138 size += 16; 1139 if (flags & TRACE_GRAPH_PRINT_CPU) 1140 size += 4; 1141 if (flags & TRACE_GRAPH_PRINT_PROC) 1142 size += 17; 1143 1144 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces); 1145 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces); 1146 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces); 1147 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces); 1148 seq_printf(s, "#%.*s||| / _-=> lock-depth \n", size, spaces); 1149 seq_printf(s, "#%.*s|||| / \n", size, spaces); 1150 } 1151 1152 void print_graph_headers_flags(struct seq_file *s, u32 flags) 1153 { 1154 int lat = trace_flags & TRACE_ITER_LATENCY_FMT; 1155 1156 if (lat) 1157 print_lat_header(s, flags); 1158 1159 /* 1st line */ 1160 seq_printf(s, "#"); 1161 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) 1162 seq_printf(s, " TIME "); 1163 if (flags & TRACE_GRAPH_PRINT_CPU) 1164 seq_printf(s, " CPU"); 1165 if (flags & TRACE_GRAPH_PRINT_PROC) 1166 seq_printf(s, " TASK/PID "); 1167 if (lat) 1168 seq_printf(s, "|||||"); 1169 if (flags & TRACE_GRAPH_PRINT_DURATION) 1170 seq_printf(s, " DURATION "); 1171 seq_printf(s, " FUNCTION CALLS\n"); 1172 1173 /* 2nd line */ 1174 seq_printf(s, "#"); 1175 if (flags & TRACE_GRAPH_PRINT_ABS_TIME) 1176 seq_printf(s, " | "); 1177 if (flags & TRACE_GRAPH_PRINT_CPU) 1178 seq_printf(s, " | "); 1179 if (flags & TRACE_GRAPH_PRINT_PROC) 1180 seq_printf(s, " | | "); 1181 if (lat) 1182 seq_printf(s, "|||||"); 1183 if (flags & TRACE_GRAPH_PRINT_DURATION) 1184 seq_printf(s, " | | "); 1185 seq_printf(s, " | | | |\n"); 1186 } 1187 1188 void print_graph_headers(struct seq_file *s) 1189 { 1190 print_graph_headers_flags(s, tracer_flags.val); 1191 } 1192 1193 void graph_trace_open(struct trace_iterator *iter) 1194 { 1195 /* pid and depth on the last trace processed */ 1196 struct fgraph_data *data; 1197 int cpu; 1198 1199 iter->private = NULL; 1200 1201 data = kzalloc(sizeof(*data), GFP_KERNEL); 1202 if (!data) 1203 goto out_err; 1204 1205 data->cpu_data = alloc_percpu(struct fgraph_cpu_data); 1206 if (!data->cpu_data) 1207 goto out_err_free; 1208 1209 for_each_possible_cpu(cpu) { 1210 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid); 1211 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); 1212 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore); 1213 *pid = -1; 1214 *depth = 0; 1215 *ignore = 0; 1216 } 1217 1218 iter->private = data; 1219 1220 return; 1221 1222 out_err_free: 1223 kfree(data); 1224 out_err: 1225 pr_warning("function graph tracer: not enough memory\n"); 1226 } 1227 1228 void graph_trace_close(struct trace_iterator *iter) 1229 { 1230 struct fgraph_data *data = iter->private; 1231 1232 if (data) { 1233 free_percpu(data->cpu_data); 1234 kfree(data); 1235 } 1236 } 1237 1238 static struct trace_event_functions graph_functions = { 1239 .trace = print_graph_function_event, 1240 }; 1241 1242 static struct trace_event graph_trace_entry_event = { 1243 .type = TRACE_GRAPH_ENT, 1244 .funcs = &graph_functions, 1245 }; 1246 1247 static struct trace_event graph_trace_ret_event = { 1248 .type = TRACE_GRAPH_RET, 1249 .funcs = &graph_functions 1250 }; 1251 1252 static struct tracer graph_trace __read_mostly = { 1253 .name = "function_graph", 1254 .open = graph_trace_open, 1255 .pipe_open = graph_trace_open, 1256 .close = graph_trace_close, 1257 .pipe_close = graph_trace_close, 1258 .wait_pipe = poll_wait_pipe, 1259 .init = graph_trace_init, 1260 .reset = graph_trace_reset, 1261 .print_line = print_graph_function, 1262 .print_header = print_graph_headers, 1263 .flags = &tracer_flags, 1264 #ifdef CONFIG_FTRACE_SELFTEST 1265 .selftest = trace_selftest_startup_function_graph, 1266 #endif 1267 }; 1268 1269 static __init int init_graph_trace(void) 1270 { 1271 max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1); 1272 1273 if (!register_ftrace_event(&graph_trace_entry_event)) { 1274 pr_warning("Warning: could not register graph trace events\n"); 1275 return 1; 1276 } 1277 1278 if (!register_ftrace_event(&graph_trace_ret_event)) { 1279 pr_warning("Warning: could not register graph trace events\n"); 1280 return 1; 1281 } 1282 1283 return register_tracer(&graph_trace); 1284 } 1285 1286 device_initcall(init_graph_trace); 1287