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