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 static 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 static 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, NULL); 494 event = ring_buffer_peek(iter->tr->buffer, iter->cpu, 495 NULL); 496 } 497 498 if (!event) 499 return NULL; 500 501 next = ring_buffer_event_data(event); 502 503 if (data) { 504 /* 505 * Save current and next entries for later reference 506 * if the output fails. 507 */ 508 data->ent = *curr; 509 data->ret = *next; 510 } 511 } 512 513 if (next->ent.type != TRACE_GRAPH_RET) 514 return NULL; 515 516 if (curr->ent.pid != next->ent.pid || 517 curr->graph_ent.func != next->ret.func) 518 return NULL; 519 520 /* this is a leaf, now advance the iterator */ 521 if (ring_iter) 522 ring_buffer_read(ring_iter, NULL); 523 524 return next; 525 } 526 527 /* Signal a overhead of time execution to the output */ 528 static int 529 print_graph_overhead(unsigned long long duration, struct trace_seq *s) 530 { 531 /* If duration disappear, we don't need anything */ 532 if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)) 533 return 1; 534 535 /* Non nested entry or return */ 536 if (duration == -1) 537 return trace_seq_printf(s, " "); 538 539 if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) { 540 /* Duration exceeded 100 msecs */ 541 if (duration > 100000ULL) 542 return trace_seq_printf(s, "! "); 543 544 /* Duration exceeded 10 msecs */ 545 if (duration > 10000ULL) 546 return trace_seq_printf(s, "+ "); 547 } 548 549 return trace_seq_printf(s, " "); 550 } 551 552 static int print_graph_abs_time(u64 t, struct trace_seq *s) 553 { 554 unsigned long usecs_rem; 555 556 usecs_rem = do_div(t, NSEC_PER_SEC); 557 usecs_rem /= 1000; 558 559 return trace_seq_printf(s, "%5lu.%06lu | ", 560 (unsigned long)t, usecs_rem); 561 } 562 563 static enum print_line_t 564 print_graph_irq(struct trace_iterator *iter, unsigned long addr, 565 enum trace_type type, int cpu, pid_t pid) 566 { 567 int ret; 568 struct trace_seq *s = &iter->seq; 569 570 if (addr < (unsigned long)__irqentry_text_start || 571 addr >= (unsigned long)__irqentry_text_end) 572 return TRACE_TYPE_UNHANDLED; 573 574 /* Absolute time */ 575 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) { 576 ret = print_graph_abs_time(iter->ts, s); 577 if (!ret) 578 return TRACE_TYPE_PARTIAL_LINE; 579 } 580 581 /* Cpu */ 582 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) { 583 ret = print_graph_cpu(s, cpu); 584 if (ret == TRACE_TYPE_PARTIAL_LINE) 585 return TRACE_TYPE_PARTIAL_LINE; 586 } 587 588 /* Proc */ 589 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) { 590 ret = print_graph_proc(s, pid); 591 if (ret == TRACE_TYPE_PARTIAL_LINE) 592 return TRACE_TYPE_PARTIAL_LINE; 593 ret = trace_seq_printf(s, " | "); 594 if (!ret) 595 return TRACE_TYPE_PARTIAL_LINE; 596 } 597 598 /* No overhead */ 599 ret = print_graph_overhead(-1, s); 600 if (!ret) 601 return TRACE_TYPE_PARTIAL_LINE; 602 603 if (type == TRACE_GRAPH_ENT) 604 ret = trace_seq_printf(s, "==========>"); 605 else 606 ret = trace_seq_printf(s, "<=========="); 607 608 if (!ret) 609 return TRACE_TYPE_PARTIAL_LINE; 610 611 /* Don't close the duration column if haven't one */ 612 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) 613 trace_seq_printf(s, " |"); 614 ret = trace_seq_printf(s, "\n"); 615 616 if (!ret) 617 return TRACE_TYPE_PARTIAL_LINE; 618 return TRACE_TYPE_HANDLED; 619 } 620 621 enum print_line_t 622 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s) 623 { 624 unsigned long nsecs_rem = do_div(duration, 1000); 625 /* log10(ULONG_MAX) + '\0' */ 626 char msecs_str[21]; 627 char nsecs_str[5]; 628 int ret, len; 629 int i; 630 631 sprintf(msecs_str, "%lu", (unsigned long) duration); 632 633 /* Print msecs */ 634 ret = trace_seq_printf(s, "%s", msecs_str); 635 if (!ret) 636 return TRACE_TYPE_PARTIAL_LINE; 637 638 len = strlen(msecs_str); 639 640 /* Print nsecs (we don't want to exceed 7 numbers) */ 641 if (len < 7) { 642 snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem); 643 ret = trace_seq_printf(s, ".%s", nsecs_str); 644 if (!ret) 645 return TRACE_TYPE_PARTIAL_LINE; 646 len += strlen(nsecs_str); 647 } 648 649 ret = trace_seq_printf(s, " us "); 650 if (!ret) 651 return TRACE_TYPE_PARTIAL_LINE; 652 653 /* Print remaining spaces to fit the row's width */ 654 for (i = len; i < 7; i++) { 655 ret = trace_seq_printf(s, " "); 656 if (!ret) 657 return TRACE_TYPE_PARTIAL_LINE; 658 } 659 return TRACE_TYPE_HANDLED; 660 } 661 662 static enum print_line_t 663 print_graph_duration(unsigned long long duration, struct trace_seq *s) 664 { 665 int ret; 666 667 ret = trace_print_graph_duration(duration, s); 668 if (ret != TRACE_TYPE_HANDLED) 669 return ret; 670 671 ret = trace_seq_printf(s, "| "); 672 if (!ret) 673 return TRACE_TYPE_PARTIAL_LINE; 674 675 return TRACE_TYPE_HANDLED; 676 } 677 678 /* Case of a leaf function on its call entry */ 679 static enum print_line_t 680 print_graph_entry_leaf(struct trace_iterator *iter, 681 struct ftrace_graph_ent_entry *entry, 682 struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s) 683 { 684 struct fgraph_data *data = iter->private; 685 struct ftrace_graph_ret *graph_ret; 686 struct ftrace_graph_ent *call; 687 unsigned long long duration; 688 int ret; 689 int i; 690 691 graph_ret = &ret_entry->ret; 692 call = &entry->graph_ent; 693 duration = graph_ret->rettime - graph_ret->calltime; 694 695 if (data) { 696 struct fgraph_cpu_data *cpu_data; 697 int cpu = iter->cpu; 698 699 cpu_data = per_cpu_ptr(data->cpu_data, cpu); 700 701 /* 702 * Comments display at + 1 to depth. Since 703 * this is a leaf function, keep the comments 704 * equal to this depth. 705 */ 706 cpu_data->depth = call->depth - 1; 707 708 /* No need to keep this function around for this depth */ 709 if (call->depth < FTRACE_RETFUNC_DEPTH) 710 cpu_data->enter_funcs[call->depth] = 0; 711 } 712 713 /* Overhead */ 714 ret = print_graph_overhead(duration, s); 715 if (!ret) 716 return TRACE_TYPE_PARTIAL_LINE; 717 718 /* Duration */ 719 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) { 720 ret = print_graph_duration(duration, s); 721 if (ret == TRACE_TYPE_PARTIAL_LINE) 722 return TRACE_TYPE_PARTIAL_LINE; 723 } 724 725 /* Function */ 726 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) { 727 ret = trace_seq_printf(s, " "); 728 if (!ret) 729 return TRACE_TYPE_PARTIAL_LINE; 730 } 731 732 ret = trace_seq_printf(s, "%ps();\n", (void *)call->func); 733 if (!ret) 734 return TRACE_TYPE_PARTIAL_LINE; 735 736 return TRACE_TYPE_HANDLED; 737 } 738 739 static enum print_line_t 740 print_graph_entry_nested(struct trace_iterator *iter, 741 struct ftrace_graph_ent_entry *entry, 742 struct trace_seq *s, int cpu) 743 { 744 struct ftrace_graph_ent *call = &entry->graph_ent; 745 struct fgraph_data *data = iter->private; 746 int ret; 747 int i; 748 749 if (data) { 750 struct fgraph_cpu_data *cpu_data; 751 int cpu = iter->cpu; 752 753 cpu_data = per_cpu_ptr(data->cpu_data, cpu); 754 cpu_data->depth = call->depth; 755 756 /* Save this function pointer to see if the exit matches */ 757 if (call->depth < FTRACE_RETFUNC_DEPTH) 758 cpu_data->enter_funcs[call->depth] = call->func; 759 } 760 761 /* No overhead */ 762 ret = print_graph_overhead(-1, s); 763 if (!ret) 764 return TRACE_TYPE_PARTIAL_LINE; 765 766 /* No time */ 767 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) { 768 ret = trace_seq_printf(s, " | "); 769 if (!ret) 770 return TRACE_TYPE_PARTIAL_LINE; 771 } 772 773 /* Function */ 774 for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) { 775 ret = trace_seq_printf(s, " "); 776 if (!ret) 777 return TRACE_TYPE_PARTIAL_LINE; 778 } 779 780 ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func); 781 if (!ret) 782 return TRACE_TYPE_PARTIAL_LINE; 783 784 /* 785 * we already consumed the current entry to check the next one 786 * and see if this is a leaf. 787 */ 788 return TRACE_TYPE_NO_CONSUME; 789 } 790 791 static enum print_line_t 792 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s, 793 int type, unsigned long addr) 794 { 795 struct fgraph_data *data = iter->private; 796 struct trace_entry *ent = iter->ent; 797 int cpu = iter->cpu; 798 int ret; 799 800 /* Pid */ 801 if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE) 802 return TRACE_TYPE_PARTIAL_LINE; 803 804 if (type) { 805 /* Interrupt */ 806 ret = print_graph_irq(iter, addr, type, cpu, ent->pid); 807 if (ret == TRACE_TYPE_PARTIAL_LINE) 808 return TRACE_TYPE_PARTIAL_LINE; 809 } 810 811 /* Absolute time */ 812 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) { 813 ret = print_graph_abs_time(iter->ts, s); 814 if (!ret) 815 return TRACE_TYPE_PARTIAL_LINE; 816 } 817 818 /* Cpu */ 819 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) { 820 ret = print_graph_cpu(s, cpu); 821 if (ret == TRACE_TYPE_PARTIAL_LINE) 822 return TRACE_TYPE_PARTIAL_LINE; 823 } 824 825 /* Proc */ 826 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) { 827 ret = print_graph_proc(s, ent->pid); 828 if (ret == TRACE_TYPE_PARTIAL_LINE) 829 return TRACE_TYPE_PARTIAL_LINE; 830 831 ret = trace_seq_printf(s, " | "); 832 if (!ret) 833 return TRACE_TYPE_PARTIAL_LINE; 834 } 835 836 /* Latency format */ 837 if (trace_flags & TRACE_ITER_LATENCY_FMT) { 838 ret = print_graph_lat_fmt(s, ent); 839 if (ret == TRACE_TYPE_PARTIAL_LINE) 840 return TRACE_TYPE_PARTIAL_LINE; 841 } 842 843 return 0; 844 } 845 846 static enum print_line_t 847 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s, 848 struct trace_iterator *iter) 849 { 850 struct fgraph_data *data = iter->private; 851 struct ftrace_graph_ent *call = &field->graph_ent; 852 struct ftrace_graph_ret_entry *leaf_ret; 853 static enum print_line_t ret; 854 int cpu = iter->cpu; 855 856 if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func)) 857 return TRACE_TYPE_PARTIAL_LINE; 858 859 leaf_ret = get_return_for_leaf(iter, field); 860 if (leaf_ret) 861 ret = print_graph_entry_leaf(iter, field, leaf_ret, s); 862 else 863 ret = print_graph_entry_nested(iter, field, s, cpu); 864 865 if (data) { 866 /* 867 * If we failed to write our output, then we need to make 868 * note of it. Because we already consumed our entry. 869 */ 870 if (s->full) { 871 data->failed = 1; 872 data->cpu = cpu; 873 } else 874 data->failed = 0; 875 } 876 877 return ret; 878 } 879 880 static enum print_line_t 881 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, 882 struct trace_entry *ent, struct trace_iterator *iter) 883 { 884 unsigned long long duration = trace->rettime - trace->calltime; 885 struct fgraph_data *data = iter->private; 886 pid_t pid = ent->pid; 887 int cpu = iter->cpu; 888 int func_match = 1; 889 int ret; 890 int i; 891 892 if (data) { 893 struct fgraph_cpu_data *cpu_data; 894 int cpu = iter->cpu; 895 896 cpu_data = per_cpu_ptr(data->cpu_data, cpu); 897 898 /* 899 * Comments display at + 1 to depth. This is the 900 * return from a function, we now want the comments 901 * to display at the same level of the bracket. 902 */ 903 cpu_data->depth = trace->depth - 1; 904 905 if (trace->depth < FTRACE_RETFUNC_DEPTH) { 906 if (cpu_data->enter_funcs[trace->depth] != trace->func) 907 func_match = 0; 908 cpu_data->enter_funcs[trace->depth] = 0; 909 } 910 } 911 912 if (print_graph_prologue(iter, s, 0, 0)) 913 return TRACE_TYPE_PARTIAL_LINE; 914 915 /* Overhead */ 916 ret = print_graph_overhead(duration, s); 917 if (!ret) 918 return TRACE_TYPE_PARTIAL_LINE; 919 920 /* Duration */ 921 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) { 922 ret = print_graph_duration(duration, s); 923 if (ret == TRACE_TYPE_PARTIAL_LINE) 924 return TRACE_TYPE_PARTIAL_LINE; 925 } 926 927 /* Closing brace */ 928 for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) { 929 ret = trace_seq_printf(s, " "); 930 if (!ret) 931 return TRACE_TYPE_PARTIAL_LINE; 932 } 933 934 /* 935 * If the return function does not have a matching entry, 936 * then the entry was lost. Instead of just printing 937 * the '}' and letting the user guess what function this 938 * belongs to, write out the function name. 939 */ 940 if (func_match) { 941 ret = trace_seq_printf(s, "}\n"); 942 if (!ret) 943 return TRACE_TYPE_PARTIAL_LINE; 944 } else { 945 ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func); 946 if (!ret) 947 return TRACE_TYPE_PARTIAL_LINE; 948 } 949 950 /* Overrun */ 951 if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) { 952 ret = trace_seq_printf(s, " (Overruns: %lu)\n", 953 trace->overrun); 954 if (!ret) 955 return TRACE_TYPE_PARTIAL_LINE; 956 } 957 958 ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid); 959 if (ret == TRACE_TYPE_PARTIAL_LINE) 960 return TRACE_TYPE_PARTIAL_LINE; 961 962 return TRACE_TYPE_HANDLED; 963 } 964 965 static enum print_line_t 966 print_graph_comment(struct trace_seq *s, struct trace_entry *ent, 967 struct trace_iterator *iter) 968 { 969 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK); 970 struct fgraph_data *data = iter->private; 971 struct trace_event *event; 972 int depth = 0; 973 int ret; 974 int i; 975 976 if (data) 977 depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth; 978 979 if (print_graph_prologue(iter, s, 0, 0)) 980 return TRACE_TYPE_PARTIAL_LINE; 981 982 /* No overhead */ 983 ret = print_graph_overhead(-1, s); 984 if (!ret) 985 return TRACE_TYPE_PARTIAL_LINE; 986 987 /* No time */ 988 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) { 989 ret = trace_seq_printf(s, " | "); 990 if (!ret) 991 return TRACE_TYPE_PARTIAL_LINE; 992 } 993 994 /* Indentation */ 995 if (depth > 0) 996 for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) { 997 ret = trace_seq_printf(s, " "); 998 if (!ret) 999 return TRACE_TYPE_PARTIAL_LINE; 1000 } 1001 1002 /* The comment */ 1003 ret = trace_seq_printf(s, "/* "); 1004 if (!ret) 1005 return TRACE_TYPE_PARTIAL_LINE; 1006 1007 switch (iter->ent->type) { 1008 case TRACE_BPRINT: 1009 ret = trace_print_bprintk_msg_only(iter); 1010 if (ret != TRACE_TYPE_HANDLED) 1011 return ret; 1012 break; 1013 case TRACE_PRINT: 1014 ret = trace_print_printk_msg_only(iter); 1015 if (ret != TRACE_TYPE_HANDLED) 1016 return ret; 1017 break; 1018 default: 1019 event = ftrace_find_event(ent->type); 1020 if (!event) 1021 return TRACE_TYPE_UNHANDLED; 1022 1023 ret = event->trace(iter, sym_flags); 1024 if (ret != TRACE_TYPE_HANDLED) 1025 return ret; 1026 } 1027 1028 /* Strip ending newline */ 1029 if (s->buffer[s->len - 1] == '\n') { 1030 s->buffer[s->len - 1] = '\0'; 1031 s->len--; 1032 } 1033 1034 ret = trace_seq_printf(s, " */\n"); 1035 if (!ret) 1036 return TRACE_TYPE_PARTIAL_LINE; 1037 1038 return TRACE_TYPE_HANDLED; 1039 } 1040 1041 1042 enum print_line_t 1043 print_graph_function(struct trace_iterator *iter) 1044 { 1045 struct ftrace_graph_ent_entry *field; 1046 struct fgraph_data *data = iter->private; 1047 struct trace_entry *entry = iter->ent; 1048 struct trace_seq *s = &iter->seq; 1049 int cpu = iter->cpu; 1050 int ret; 1051 1052 if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) { 1053 per_cpu_ptr(data->cpu_data, cpu)->ignore = 0; 1054 return TRACE_TYPE_HANDLED; 1055 } 1056 1057 /* 1058 * If the last output failed, there's a possibility we need 1059 * to print out the missing entry which would never go out. 1060 */ 1061 if (data && data->failed) { 1062 field = &data->ent; 1063 iter->cpu = data->cpu; 1064 ret = print_graph_entry(field, s, iter); 1065 if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) { 1066 per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1; 1067 ret = TRACE_TYPE_NO_CONSUME; 1068 } 1069 iter->cpu = cpu; 1070 return ret; 1071 } 1072 1073 switch (entry->type) { 1074 case TRACE_GRAPH_ENT: { 1075 /* 1076 * print_graph_entry() may consume the current event, 1077 * thus @field may become invalid, so we need to save it. 1078 * sizeof(struct ftrace_graph_ent_entry) is very small, 1079 * it can be safely saved at the stack. 1080 */ 1081 struct ftrace_graph_ent_entry saved; 1082 trace_assign_type(field, entry); 1083 saved = *field; 1084 return print_graph_entry(&saved, s, iter); 1085 } 1086 case TRACE_GRAPH_RET: { 1087 struct ftrace_graph_ret_entry *field; 1088 trace_assign_type(field, entry); 1089 return print_graph_return(&field->ret, s, entry, iter); 1090 } 1091 default: 1092 return print_graph_comment(s, entry, iter); 1093 } 1094 1095 return TRACE_TYPE_HANDLED; 1096 } 1097 1098 static void print_lat_header(struct seq_file *s) 1099 { 1100 static const char spaces[] = " " /* 16 spaces */ 1101 " " /* 4 spaces */ 1102 " "; /* 17 spaces */ 1103 int size = 0; 1104 1105 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) 1106 size += 16; 1107 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) 1108 size += 4; 1109 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) 1110 size += 17; 1111 1112 seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces); 1113 seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces); 1114 seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces); 1115 seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces); 1116 seq_printf(s, "#%.*s||| / _-=> lock-depth \n", size, spaces); 1117 seq_printf(s, "#%.*s|||| / \n", size, spaces); 1118 } 1119 1120 static void print_graph_headers(struct seq_file *s) 1121 { 1122 int lat = trace_flags & TRACE_ITER_LATENCY_FMT; 1123 1124 if (lat) 1125 print_lat_header(s); 1126 1127 /* 1st line */ 1128 seq_printf(s, "#"); 1129 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) 1130 seq_printf(s, " TIME "); 1131 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) 1132 seq_printf(s, " CPU"); 1133 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) 1134 seq_printf(s, " TASK/PID "); 1135 if (lat) 1136 seq_printf(s, "|||||"); 1137 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) 1138 seq_printf(s, " DURATION "); 1139 seq_printf(s, " FUNCTION CALLS\n"); 1140 1141 /* 2nd line */ 1142 seq_printf(s, "#"); 1143 if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) 1144 seq_printf(s, " | "); 1145 if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) 1146 seq_printf(s, " | "); 1147 if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) 1148 seq_printf(s, " | | "); 1149 if (lat) 1150 seq_printf(s, "|||||"); 1151 if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) 1152 seq_printf(s, " | | "); 1153 seq_printf(s, " | | | |\n"); 1154 } 1155 1156 static void graph_trace_open(struct trace_iterator *iter) 1157 { 1158 /* pid and depth on the last trace processed */ 1159 struct fgraph_data *data; 1160 int cpu; 1161 1162 iter->private = NULL; 1163 1164 data = kzalloc(sizeof(*data), GFP_KERNEL); 1165 if (!data) 1166 goto out_err; 1167 1168 data->cpu_data = alloc_percpu(struct fgraph_cpu_data); 1169 if (!data->cpu_data) 1170 goto out_err_free; 1171 1172 for_each_possible_cpu(cpu) { 1173 pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid); 1174 int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); 1175 int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore); 1176 *pid = -1; 1177 *depth = 0; 1178 *ignore = 0; 1179 } 1180 1181 iter->private = data; 1182 1183 return; 1184 1185 out_err_free: 1186 kfree(data); 1187 out_err: 1188 pr_warning("function graph tracer: not enough memory\n"); 1189 } 1190 1191 static void graph_trace_close(struct trace_iterator *iter) 1192 { 1193 struct fgraph_data *data = iter->private; 1194 1195 if (data) { 1196 free_percpu(data->cpu_data); 1197 kfree(data); 1198 } 1199 } 1200 1201 static struct tracer graph_trace __read_mostly = { 1202 .name = "function_graph", 1203 .open = graph_trace_open, 1204 .pipe_open = graph_trace_open, 1205 .close = graph_trace_close, 1206 .pipe_close = graph_trace_close, 1207 .wait_pipe = poll_wait_pipe, 1208 .init = graph_trace_init, 1209 .reset = graph_trace_reset, 1210 .print_line = print_graph_function, 1211 .print_header = print_graph_headers, 1212 .flags = &tracer_flags, 1213 #ifdef CONFIG_FTRACE_SELFTEST 1214 .selftest = trace_selftest_startup_function_graph, 1215 #endif 1216 }; 1217 1218 static __init int init_graph_trace(void) 1219 { 1220 max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1); 1221 1222 return register_tracer(&graph_trace); 1223 } 1224 1225 device_initcall(init_graph_trace); 1226