1 /* 2 * Infrastructure for profiling code inserted by 'gcc -pg'. 3 * 4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> 5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com> 6 * 7 * Originally ported from the -rt patch by: 8 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com> 9 * 10 * Based on code in the latency_tracer, that is: 11 * 12 * Copyright (C) 2004-2006 Ingo Molnar 13 * Copyright (C) 2004 Nadia Yvette Chambers 14 */ 15 16 #include <linux/stop_machine.h> 17 #include <linux/clocksource.h> 18 #include <linux/sched/task.h> 19 #include <linux/kallsyms.h> 20 #include <linux/seq_file.h> 21 #include <linux/suspend.h> 22 #include <linux/tracefs.h> 23 #include <linux/hardirq.h> 24 #include <linux/kthread.h> 25 #include <linux/uaccess.h> 26 #include <linux/bsearch.h> 27 #include <linux/module.h> 28 #include <linux/ftrace.h> 29 #include <linux/sysctl.h> 30 #include <linux/slab.h> 31 #include <linux/ctype.h> 32 #include <linux/sort.h> 33 #include <linux/list.h> 34 #include <linux/hash.h> 35 #include <linux/rcupdate.h> 36 37 #include <trace/events/sched.h> 38 39 #include <asm/sections.h> 40 #include <asm/setup.h> 41 42 #include "trace_output.h" 43 #include "trace_stat.h" 44 45 #define FTRACE_WARN_ON(cond) \ 46 ({ \ 47 int ___r = cond; \ 48 if (WARN_ON(___r)) \ 49 ftrace_kill(); \ 50 ___r; \ 51 }) 52 53 #define FTRACE_WARN_ON_ONCE(cond) \ 54 ({ \ 55 int ___r = cond; \ 56 if (WARN_ON_ONCE(___r)) \ 57 ftrace_kill(); \ 58 ___r; \ 59 }) 60 61 /* hash bits for specific function selection */ 62 #define FTRACE_HASH_BITS 7 63 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS) 64 #define FTRACE_HASH_DEFAULT_BITS 10 65 #define FTRACE_HASH_MAX_BITS 12 66 67 #ifdef CONFIG_DYNAMIC_FTRACE 68 #define INIT_OPS_HASH(opsname) \ 69 .func_hash = &opsname.local_hash, \ 70 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock), 71 #define ASSIGN_OPS_HASH(opsname, val) \ 72 .func_hash = val, \ 73 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock), 74 #else 75 #define INIT_OPS_HASH(opsname) 76 #define ASSIGN_OPS_HASH(opsname, val) 77 #endif 78 79 static struct ftrace_ops ftrace_list_end __read_mostly = { 80 .func = ftrace_stub, 81 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB, 82 INIT_OPS_HASH(ftrace_list_end) 83 }; 84 85 /* ftrace_enabled is a method to turn ftrace on or off */ 86 int ftrace_enabled __read_mostly; 87 static int last_ftrace_enabled; 88 89 /* Current function tracing op */ 90 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end; 91 /* What to set function_trace_op to */ 92 static struct ftrace_ops *set_function_trace_op; 93 94 static bool ftrace_pids_enabled(struct ftrace_ops *ops) 95 { 96 struct trace_array *tr; 97 98 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private) 99 return false; 100 101 tr = ops->private; 102 103 return tr->function_pids != NULL; 104 } 105 106 static void ftrace_update_trampoline(struct ftrace_ops *ops); 107 108 /* 109 * ftrace_disabled is set when an anomaly is discovered. 110 * ftrace_disabled is much stronger than ftrace_enabled. 111 */ 112 static int ftrace_disabled __read_mostly; 113 114 static DEFINE_MUTEX(ftrace_lock); 115 116 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end; 117 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; 118 static struct ftrace_ops global_ops; 119 120 #if ARCH_SUPPORTS_FTRACE_OPS 121 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, 122 struct ftrace_ops *op, struct pt_regs *regs); 123 #else 124 /* See comment below, where ftrace_ops_list_func is defined */ 125 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip); 126 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops) 127 #endif 128 129 /* 130 * Traverse the ftrace_global_list, invoking all entries. The reason that we 131 * can use rcu_dereference_raw_notrace() is that elements removed from this list 132 * are simply leaked, so there is no need to interact with a grace-period 133 * mechanism. The rcu_dereference_raw_notrace() calls are needed to handle 134 * concurrent insertions into the ftrace_global_list. 135 * 136 * Silly Alpha and silly pointer-speculation compiler optimizations! 137 */ 138 #define do_for_each_ftrace_op(op, list) \ 139 op = rcu_dereference_raw_notrace(list); \ 140 do 141 142 /* 143 * Optimized for just a single item in the list (as that is the normal case). 144 */ 145 #define while_for_each_ftrace_op(op) \ 146 while (likely(op = rcu_dereference_raw_notrace((op)->next)) && \ 147 unlikely((op) != &ftrace_list_end)) 148 149 static inline void ftrace_ops_init(struct ftrace_ops *ops) 150 { 151 #ifdef CONFIG_DYNAMIC_FTRACE 152 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) { 153 mutex_init(&ops->local_hash.regex_lock); 154 ops->func_hash = &ops->local_hash; 155 ops->flags |= FTRACE_OPS_FL_INITIALIZED; 156 } 157 #endif 158 } 159 160 /** 161 * ftrace_nr_registered_ops - return number of ops registered 162 * 163 * Returns the number of ftrace_ops registered and tracing functions 164 */ 165 int ftrace_nr_registered_ops(void) 166 { 167 struct ftrace_ops *ops; 168 int cnt = 0; 169 170 mutex_lock(&ftrace_lock); 171 172 for (ops = ftrace_ops_list; 173 ops != &ftrace_list_end; ops = ops->next) 174 cnt++; 175 176 mutex_unlock(&ftrace_lock); 177 178 return cnt; 179 } 180 181 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, 182 struct ftrace_ops *op, struct pt_regs *regs) 183 { 184 struct trace_array *tr = op->private; 185 186 if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid)) 187 return; 188 189 op->saved_func(ip, parent_ip, op, regs); 190 } 191 192 /** 193 * clear_ftrace_function - reset the ftrace function 194 * 195 * This NULLs the ftrace function and in essence stops 196 * tracing. There may be lag 197 */ 198 void clear_ftrace_function(void) 199 { 200 ftrace_trace_function = ftrace_stub; 201 } 202 203 static void per_cpu_ops_disable_all(struct ftrace_ops *ops) 204 { 205 int cpu; 206 207 for_each_possible_cpu(cpu) 208 *per_cpu_ptr(ops->disabled, cpu) = 1; 209 } 210 211 static int per_cpu_ops_alloc(struct ftrace_ops *ops) 212 { 213 int __percpu *disabled; 214 215 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU))) 216 return -EINVAL; 217 218 disabled = alloc_percpu(int); 219 if (!disabled) 220 return -ENOMEM; 221 222 ops->disabled = disabled; 223 per_cpu_ops_disable_all(ops); 224 return 0; 225 } 226 227 static void ftrace_sync(struct work_struct *work) 228 { 229 /* 230 * This function is just a stub to implement a hard force 231 * of synchronize_sched(). This requires synchronizing 232 * tasks even in userspace and idle. 233 * 234 * Yes, function tracing is rude. 235 */ 236 } 237 238 static void ftrace_sync_ipi(void *data) 239 { 240 /* Probably not needed, but do it anyway */ 241 smp_rmb(); 242 } 243 244 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 245 static void update_function_graph_func(void); 246 247 /* Both enabled by default (can be cleared by function_graph tracer flags */ 248 static bool fgraph_sleep_time = true; 249 static bool fgraph_graph_time = true; 250 251 #else 252 static inline void update_function_graph_func(void) { } 253 #endif 254 255 256 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops) 257 { 258 /* 259 * If this is a dynamic, RCU, or per CPU ops, or we force list func, 260 * then it needs to call the list anyway. 261 */ 262 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU | 263 FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC) 264 return ftrace_ops_list_func; 265 266 return ftrace_ops_get_func(ops); 267 } 268 269 static void update_ftrace_function(void) 270 { 271 ftrace_func_t func; 272 273 /* 274 * Prepare the ftrace_ops that the arch callback will use. 275 * If there's only one ftrace_ops registered, the ftrace_ops_list 276 * will point to the ops we want. 277 */ 278 set_function_trace_op = ftrace_ops_list; 279 280 /* If there's no ftrace_ops registered, just call the stub function */ 281 if (ftrace_ops_list == &ftrace_list_end) { 282 func = ftrace_stub; 283 284 /* 285 * If we are at the end of the list and this ops is 286 * recursion safe and not dynamic and the arch supports passing ops, 287 * then have the mcount trampoline call the function directly. 288 */ 289 } else if (ftrace_ops_list->next == &ftrace_list_end) { 290 func = ftrace_ops_get_list_func(ftrace_ops_list); 291 292 } else { 293 /* Just use the default ftrace_ops */ 294 set_function_trace_op = &ftrace_list_end; 295 func = ftrace_ops_list_func; 296 } 297 298 update_function_graph_func(); 299 300 /* If there's no change, then do nothing more here */ 301 if (ftrace_trace_function == func) 302 return; 303 304 /* 305 * If we are using the list function, it doesn't care 306 * about the function_trace_ops. 307 */ 308 if (func == ftrace_ops_list_func) { 309 ftrace_trace_function = func; 310 /* 311 * Don't even bother setting function_trace_ops, 312 * it would be racy to do so anyway. 313 */ 314 return; 315 } 316 317 #ifndef CONFIG_DYNAMIC_FTRACE 318 /* 319 * For static tracing, we need to be a bit more careful. 320 * The function change takes affect immediately. Thus, 321 * we need to coorditate the setting of the function_trace_ops 322 * with the setting of the ftrace_trace_function. 323 * 324 * Set the function to the list ops, which will call the 325 * function we want, albeit indirectly, but it handles the 326 * ftrace_ops and doesn't depend on function_trace_op. 327 */ 328 ftrace_trace_function = ftrace_ops_list_func; 329 /* 330 * Make sure all CPUs see this. Yes this is slow, but static 331 * tracing is slow and nasty to have enabled. 332 */ 333 schedule_on_each_cpu(ftrace_sync); 334 /* Now all cpus are using the list ops. */ 335 function_trace_op = set_function_trace_op; 336 /* Make sure the function_trace_op is visible on all CPUs */ 337 smp_wmb(); 338 /* Nasty way to force a rmb on all cpus */ 339 smp_call_function(ftrace_sync_ipi, NULL, 1); 340 /* OK, we are all set to update the ftrace_trace_function now! */ 341 #endif /* !CONFIG_DYNAMIC_FTRACE */ 342 343 ftrace_trace_function = func; 344 } 345 346 int using_ftrace_ops_list_func(void) 347 { 348 return ftrace_trace_function == ftrace_ops_list_func; 349 } 350 351 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) 352 { 353 ops->next = *list; 354 /* 355 * We are entering ops into the list but another 356 * CPU might be walking that list. We need to make sure 357 * the ops->next pointer is valid before another CPU sees 358 * the ops pointer included into the list. 359 */ 360 rcu_assign_pointer(*list, ops); 361 } 362 363 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) 364 { 365 struct ftrace_ops **p; 366 367 /* 368 * If we are removing the last function, then simply point 369 * to the ftrace_stub. 370 */ 371 if (*list == ops && ops->next == &ftrace_list_end) { 372 *list = &ftrace_list_end; 373 return 0; 374 } 375 376 for (p = list; *p != &ftrace_list_end; p = &(*p)->next) 377 if (*p == ops) 378 break; 379 380 if (*p != ops) 381 return -1; 382 383 *p = (*p)->next; 384 return 0; 385 } 386 387 static void ftrace_update_trampoline(struct ftrace_ops *ops); 388 389 static int __register_ftrace_function(struct ftrace_ops *ops) 390 { 391 if (ops->flags & FTRACE_OPS_FL_DELETED) 392 return -EINVAL; 393 394 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED)) 395 return -EBUSY; 396 397 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS 398 /* 399 * If the ftrace_ops specifies SAVE_REGS, then it only can be used 400 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set. 401 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant. 402 */ 403 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS && 404 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)) 405 return -EINVAL; 406 407 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED) 408 ops->flags |= FTRACE_OPS_FL_SAVE_REGS; 409 #endif 410 411 if (!core_kernel_data((unsigned long)ops)) 412 ops->flags |= FTRACE_OPS_FL_DYNAMIC; 413 414 if (ops->flags & FTRACE_OPS_FL_PER_CPU) { 415 if (per_cpu_ops_alloc(ops)) 416 return -ENOMEM; 417 } 418 419 add_ftrace_ops(&ftrace_ops_list, ops); 420 421 /* Always save the function, and reset at unregistering */ 422 ops->saved_func = ops->func; 423 424 if (ftrace_pids_enabled(ops)) 425 ops->func = ftrace_pid_func; 426 427 ftrace_update_trampoline(ops); 428 429 if (ftrace_enabled) 430 update_ftrace_function(); 431 432 return 0; 433 } 434 435 static int __unregister_ftrace_function(struct ftrace_ops *ops) 436 { 437 int ret; 438 439 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED))) 440 return -EBUSY; 441 442 ret = remove_ftrace_ops(&ftrace_ops_list, ops); 443 444 if (ret < 0) 445 return ret; 446 447 if (ftrace_enabled) 448 update_ftrace_function(); 449 450 ops->func = ops->saved_func; 451 452 return 0; 453 } 454 455 static void ftrace_update_pid_func(void) 456 { 457 struct ftrace_ops *op; 458 459 /* Only do something if we are tracing something */ 460 if (ftrace_trace_function == ftrace_stub) 461 return; 462 463 do_for_each_ftrace_op(op, ftrace_ops_list) { 464 if (op->flags & FTRACE_OPS_FL_PID) { 465 op->func = ftrace_pids_enabled(op) ? 466 ftrace_pid_func : op->saved_func; 467 ftrace_update_trampoline(op); 468 } 469 } while_for_each_ftrace_op(op); 470 471 update_ftrace_function(); 472 } 473 474 #ifdef CONFIG_FUNCTION_PROFILER 475 struct ftrace_profile { 476 struct hlist_node node; 477 unsigned long ip; 478 unsigned long counter; 479 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 480 unsigned long long time; 481 unsigned long long time_squared; 482 #endif 483 }; 484 485 struct ftrace_profile_page { 486 struct ftrace_profile_page *next; 487 unsigned long index; 488 struct ftrace_profile records[]; 489 }; 490 491 struct ftrace_profile_stat { 492 atomic_t disabled; 493 struct hlist_head *hash; 494 struct ftrace_profile_page *pages; 495 struct ftrace_profile_page *start; 496 struct tracer_stat stat; 497 }; 498 499 #define PROFILE_RECORDS_SIZE \ 500 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records)) 501 502 #define PROFILES_PER_PAGE \ 503 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile)) 504 505 static int ftrace_profile_enabled __read_mostly; 506 507 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */ 508 static DEFINE_MUTEX(ftrace_profile_lock); 509 510 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats); 511 512 #define FTRACE_PROFILE_HASH_BITS 10 513 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS) 514 515 static void * 516 function_stat_next(void *v, int idx) 517 { 518 struct ftrace_profile *rec = v; 519 struct ftrace_profile_page *pg; 520 521 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK); 522 523 again: 524 if (idx != 0) 525 rec++; 526 527 if ((void *)rec >= (void *)&pg->records[pg->index]) { 528 pg = pg->next; 529 if (!pg) 530 return NULL; 531 rec = &pg->records[0]; 532 if (!rec->counter) 533 goto again; 534 } 535 536 return rec; 537 } 538 539 static void *function_stat_start(struct tracer_stat *trace) 540 { 541 struct ftrace_profile_stat *stat = 542 container_of(trace, struct ftrace_profile_stat, stat); 543 544 if (!stat || !stat->start) 545 return NULL; 546 547 return function_stat_next(&stat->start->records[0], 0); 548 } 549 550 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 551 /* function graph compares on total time */ 552 static int function_stat_cmp(void *p1, void *p2) 553 { 554 struct ftrace_profile *a = p1; 555 struct ftrace_profile *b = p2; 556 557 if (a->time < b->time) 558 return -1; 559 if (a->time > b->time) 560 return 1; 561 else 562 return 0; 563 } 564 #else 565 /* not function graph compares against hits */ 566 static int function_stat_cmp(void *p1, void *p2) 567 { 568 struct ftrace_profile *a = p1; 569 struct ftrace_profile *b = p2; 570 571 if (a->counter < b->counter) 572 return -1; 573 if (a->counter > b->counter) 574 return 1; 575 else 576 return 0; 577 } 578 #endif 579 580 static int function_stat_headers(struct seq_file *m) 581 { 582 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 583 seq_puts(m, " Function " 584 "Hit Time Avg s^2\n" 585 " -------- " 586 "--- ---- --- ---\n"); 587 #else 588 seq_puts(m, " Function Hit\n" 589 " -------- ---\n"); 590 #endif 591 return 0; 592 } 593 594 static int function_stat_show(struct seq_file *m, void *v) 595 { 596 struct ftrace_profile *rec = v; 597 char str[KSYM_SYMBOL_LEN]; 598 int ret = 0; 599 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 600 static struct trace_seq s; 601 unsigned long long avg; 602 unsigned long long stddev; 603 #endif 604 mutex_lock(&ftrace_profile_lock); 605 606 /* we raced with function_profile_reset() */ 607 if (unlikely(rec->counter == 0)) { 608 ret = -EBUSY; 609 goto out; 610 } 611 612 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 613 avg = rec->time; 614 do_div(avg, rec->counter); 615 if (tracing_thresh && (avg < tracing_thresh)) 616 goto out; 617 #endif 618 619 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); 620 seq_printf(m, " %-30.30s %10lu", str, rec->counter); 621 622 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 623 seq_puts(m, " "); 624 625 /* Sample standard deviation (s^2) */ 626 if (rec->counter <= 1) 627 stddev = 0; 628 else { 629 /* 630 * Apply Welford's method: 631 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) 632 */ 633 stddev = rec->counter * rec->time_squared - 634 rec->time * rec->time; 635 636 /* 637 * Divide only 1000 for ns^2 -> us^2 conversion. 638 * trace_print_graph_duration will divide 1000 again. 639 */ 640 do_div(stddev, rec->counter * (rec->counter - 1) * 1000); 641 } 642 643 trace_seq_init(&s); 644 trace_print_graph_duration(rec->time, &s); 645 trace_seq_puts(&s, " "); 646 trace_print_graph_duration(avg, &s); 647 trace_seq_puts(&s, " "); 648 trace_print_graph_duration(stddev, &s); 649 trace_print_seq(m, &s); 650 #endif 651 seq_putc(m, '\n'); 652 out: 653 mutex_unlock(&ftrace_profile_lock); 654 655 return ret; 656 } 657 658 static void ftrace_profile_reset(struct ftrace_profile_stat *stat) 659 { 660 struct ftrace_profile_page *pg; 661 662 pg = stat->pages = stat->start; 663 664 while (pg) { 665 memset(pg->records, 0, PROFILE_RECORDS_SIZE); 666 pg->index = 0; 667 pg = pg->next; 668 } 669 670 memset(stat->hash, 0, 671 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head)); 672 } 673 674 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat) 675 { 676 struct ftrace_profile_page *pg; 677 int functions; 678 int pages; 679 int i; 680 681 /* If we already allocated, do nothing */ 682 if (stat->pages) 683 return 0; 684 685 stat->pages = (void *)get_zeroed_page(GFP_KERNEL); 686 if (!stat->pages) 687 return -ENOMEM; 688 689 #ifdef CONFIG_DYNAMIC_FTRACE 690 functions = ftrace_update_tot_cnt; 691 #else 692 /* 693 * We do not know the number of functions that exist because 694 * dynamic tracing is what counts them. With past experience 695 * we have around 20K functions. That should be more than enough. 696 * It is highly unlikely we will execute every function in 697 * the kernel. 698 */ 699 functions = 20000; 700 #endif 701 702 pg = stat->start = stat->pages; 703 704 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE); 705 706 for (i = 1; i < pages; i++) { 707 pg->next = (void *)get_zeroed_page(GFP_KERNEL); 708 if (!pg->next) 709 goto out_free; 710 pg = pg->next; 711 } 712 713 return 0; 714 715 out_free: 716 pg = stat->start; 717 while (pg) { 718 unsigned long tmp = (unsigned long)pg; 719 720 pg = pg->next; 721 free_page(tmp); 722 } 723 724 stat->pages = NULL; 725 stat->start = NULL; 726 727 return -ENOMEM; 728 } 729 730 static int ftrace_profile_init_cpu(int cpu) 731 { 732 struct ftrace_profile_stat *stat; 733 int size; 734 735 stat = &per_cpu(ftrace_profile_stats, cpu); 736 737 if (stat->hash) { 738 /* If the profile is already created, simply reset it */ 739 ftrace_profile_reset(stat); 740 return 0; 741 } 742 743 /* 744 * We are profiling all functions, but usually only a few thousand 745 * functions are hit. We'll make a hash of 1024 items. 746 */ 747 size = FTRACE_PROFILE_HASH_SIZE; 748 749 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL); 750 751 if (!stat->hash) 752 return -ENOMEM; 753 754 /* Preallocate the function profiling pages */ 755 if (ftrace_profile_pages_init(stat) < 0) { 756 kfree(stat->hash); 757 stat->hash = NULL; 758 return -ENOMEM; 759 } 760 761 return 0; 762 } 763 764 static int ftrace_profile_init(void) 765 { 766 int cpu; 767 int ret = 0; 768 769 for_each_possible_cpu(cpu) { 770 ret = ftrace_profile_init_cpu(cpu); 771 if (ret) 772 break; 773 } 774 775 return ret; 776 } 777 778 /* interrupts must be disabled */ 779 static struct ftrace_profile * 780 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip) 781 { 782 struct ftrace_profile *rec; 783 struct hlist_head *hhd; 784 unsigned long key; 785 786 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS); 787 hhd = &stat->hash[key]; 788 789 if (hlist_empty(hhd)) 790 return NULL; 791 792 hlist_for_each_entry_rcu_notrace(rec, hhd, node) { 793 if (rec->ip == ip) 794 return rec; 795 } 796 797 return NULL; 798 } 799 800 static void ftrace_add_profile(struct ftrace_profile_stat *stat, 801 struct ftrace_profile *rec) 802 { 803 unsigned long key; 804 805 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS); 806 hlist_add_head_rcu(&rec->node, &stat->hash[key]); 807 } 808 809 /* 810 * The memory is already allocated, this simply finds a new record to use. 811 */ 812 static struct ftrace_profile * 813 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip) 814 { 815 struct ftrace_profile *rec = NULL; 816 817 /* prevent recursion (from NMIs) */ 818 if (atomic_inc_return(&stat->disabled) != 1) 819 goto out; 820 821 /* 822 * Try to find the function again since an NMI 823 * could have added it 824 */ 825 rec = ftrace_find_profiled_func(stat, ip); 826 if (rec) 827 goto out; 828 829 if (stat->pages->index == PROFILES_PER_PAGE) { 830 if (!stat->pages->next) 831 goto out; 832 stat->pages = stat->pages->next; 833 } 834 835 rec = &stat->pages->records[stat->pages->index++]; 836 rec->ip = ip; 837 ftrace_add_profile(stat, rec); 838 839 out: 840 atomic_dec(&stat->disabled); 841 842 return rec; 843 } 844 845 static void 846 function_profile_call(unsigned long ip, unsigned long parent_ip, 847 struct ftrace_ops *ops, struct pt_regs *regs) 848 { 849 struct ftrace_profile_stat *stat; 850 struct ftrace_profile *rec; 851 unsigned long flags; 852 853 if (!ftrace_profile_enabled) 854 return; 855 856 local_irq_save(flags); 857 858 stat = this_cpu_ptr(&ftrace_profile_stats); 859 if (!stat->hash || !ftrace_profile_enabled) 860 goto out; 861 862 rec = ftrace_find_profiled_func(stat, ip); 863 if (!rec) { 864 rec = ftrace_profile_alloc(stat, ip); 865 if (!rec) 866 goto out; 867 } 868 869 rec->counter++; 870 out: 871 local_irq_restore(flags); 872 } 873 874 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 875 static int profile_graph_entry(struct ftrace_graph_ent *trace) 876 { 877 int index = trace->depth; 878 879 function_profile_call(trace->func, 0, NULL, NULL); 880 881 if (index >= 0 && index < FTRACE_RETFUNC_DEPTH) 882 current->ret_stack[index].subtime = 0; 883 884 return 1; 885 } 886 887 static void profile_graph_return(struct ftrace_graph_ret *trace) 888 { 889 struct ftrace_profile_stat *stat; 890 unsigned long long calltime; 891 struct ftrace_profile *rec; 892 unsigned long flags; 893 894 local_irq_save(flags); 895 stat = this_cpu_ptr(&ftrace_profile_stats); 896 if (!stat->hash || !ftrace_profile_enabled) 897 goto out; 898 899 /* If the calltime was zero'd ignore it */ 900 if (!trace->calltime) 901 goto out; 902 903 calltime = trace->rettime - trace->calltime; 904 905 if (!fgraph_graph_time) { 906 int index; 907 908 index = trace->depth; 909 910 /* Append this call time to the parent time to subtract */ 911 if (index) 912 current->ret_stack[index - 1].subtime += calltime; 913 914 if (current->ret_stack[index].subtime < calltime) 915 calltime -= current->ret_stack[index].subtime; 916 else 917 calltime = 0; 918 } 919 920 rec = ftrace_find_profiled_func(stat, trace->func); 921 if (rec) { 922 rec->time += calltime; 923 rec->time_squared += calltime * calltime; 924 } 925 926 out: 927 local_irq_restore(flags); 928 } 929 930 static int register_ftrace_profiler(void) 931 { 932 return register_ftrace_graph(&profile_graph_return, 933 &profile_graph_entry); 934 } 935 936 static void unregister_ftrace_profiler(void) 937 { 938 unregister_ftrace_graph(); 939 } 940 #else 941 static struct ftrace_ops ftrace_profile_ops __read_mostly = { 942 .func = function_profile_call, 943 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED, 944 INIT_OPS_HASH(ftrace_profile_ops) 945 }; 946 947 static int register_ftrace_profiler(void) 948 { 949 return register_ftrace_function(&ftrace_profile_ops); 950 } 951 952 static void unregister_ftrace_profiler(void) 953 { 954 unregister_ftrace_function(&ftrace_profile_ops); 955 } 956 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 957 958 static ssize_t 959 ftrace_profile_write(struct file *filp, const char __user *ubuf, 960 size_t cnt, loff_t *ppos) 961 { 962 unsigned long val; 963 int ret; 964 965 ret = kstrtoul_from_user(ubuf, cnt, 10, &val); 966 if (ret) 967 return ret; 968 969 val = !!val; 970 971 mutex_lock(&ftrace_profile_lock); 972 if (ftrace_profile_enabled ^ val) { 973 if (val) { 974 ret = ftrace_profile_init(); 975 if (ret < 0) { 976 cnt = ret; 977 goto out; 978 } 979 980 ret = register_ftrace_profiler(); 981 if (ret < 0) { 982 cnt = ret; 983 goto out; 984 } 985 ftrace_profile_enabled = 1; 986 } else { 987 ftrace_profile_enabled = 0; 988 /* 989 * unregister_ftrace_profiler calls stop_machine 990 * so this acts like an synchronize_sched. 991 */ 992 unregister_ftrace_profiler(); 993 } 994 } 995 out: 996 mutex_unlock(&ftrace_profile_lock); 997 998 *ppos += cnt; 999 1000 return cnt; 1001 } 1002 1003 static ssize_t 1004 ftrace_profile_read(struct file *filp, char __user *ubuf, 1005 size_t cnt, loff_t *ppos) 1006 { 1007 char buf[64]; /* big enough to hold a number */ 1008 int r; 1009 1010 r = sprintf(buf, "%u\n", ftrace_profile_enabled); 1011 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); 1012 } 1013 1014 static const struct file_operations ftrace_profile_fops = { 1015 .open = tracing_open_generic, 1016 .read = ftrace_profile_read, 1017 .write = ftrace_profile_write, 1018 .llseek = default_llseek, 1019 }; 1020 1021 /* used to initialize the real stat files */ 1022 static struct tracer_stat function_stats __initdata = { 1023 .name = "functions", 1024 .stat_start = function_stat_start, 1025 .stat_next = function_stat_next, 1026 .stat_cmp = function_stat_cmp, 1027 .stat_headers = function_stat_headers, 1028 .stat_show = function_stat_show 1029 }; 1030 1031 static __init void ftrace_profile_tracefs(struct dentry *d_tracer) 1032 { 1033 struct ftrace_profile_stat *stat; 1034 struct dentry *entry; 1035 char *name; 1036 int ret; 1037 int cpu; 1038 1039 for_each_possible_cpu(cpu) { 1040 stat = &per_cpu(ftrace_profile_stats, cpu); 1041 1042 name = kasprintf(GFP_KERNEL, "function%d", cpu); 1043 if (!name) { 1044 /* 1045 * The files created are permanent, if something happens 1046 * we still do not free memory. 1047 */ 1048 WARN(1, 1049 "Could not allocate stat file for cpu %d\n", 1050 cpu); 1051 return; 1052 } 1053 stat->stat = function_stats; 1054 stat->stat.name = name; 1055 ret = register_stat_tracer(&stat->stat); 1056 if (ret) { 1057 WARN(1, 1058 "Could not register function stat for cpu %d\n", 1059 cpu); 1060 kfree(name); 1061 return; 1062 } 1063 } 1064 1065 entry = tracefs_create_file("function_profile_enabled", 0644, 1066 d_tracer, NULL, &ftrace_profile_fops); 1067 if (!entry) 1068 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n"); 1069 } 1070 1071 #else /* CONFIG_FUNCTION_PROFILER */ 1072 static __init void ftrace_profile_tracefs(struct dentry *d_tracer) 1073 { 1074 } 1075 #endif /* CONFIG_FUNCTION_PROFILER */ 1076 1077 static struct pid * const ftrace_swapper_pid = &init_struct_pid; 1078 1079 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1080 static int ftrace_graph_active; 1081 #else 1082 # define ftrace_graph_active 0 1083 #endif 1084 1085 #ifdef CONFIG_DYNAMIC_FTRACE 1086 1087 static struct ftrace_ops *removed_ops; 1088 1089 /* 1090 * Set when doing a global update, like enabling all recs or disabling them. 1091 * It is not set when just updating a single ftrace_ops. 1092 */ 1093 static bool update_all_ops; 1094 1095 #ifndef CONFIG_FTRACE_MCOUNT_RECORD 1096 # error Dynamic ftrace depends on MCOUNT_RECORD 1097 #endif 1098 1099 struct ftrace_func_entry { 1100 struct hlist_node hlist; 1101 unsigned long ip; 1102 }; 1103 1104 struct ftrace_func_probe { 1105 struct ftrace_probe_ops *probe_ops; 1106 struct ftrace_ops ops; 1107 struct trace_array *tr; 1108 struct list_head list; 1109 void *data; 1110 int ref; 1111 }; 1112 1113 /* 1114 * We make these constant because no one should touch them, 1115 * but they are used as the default "empty hash", to avoid allocating 1116 * it all the time. These are in a read only section such that if 1117 * anyone does try to modify it, it will cause an exception. 1118 */ 1119 static const struct hlist_head empty_buckets[1]; 1120 static const struct ftrace_hash empty_hash = { 1121 .buckets = (struct hlist_head *)empty_buckets, 1122 }; 1123 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash) 1124 1125 static struct ftrace_ops global_ops = { 1126 .func = ftrace_stub, 1127 .local_hash.notrace_hash = EMPTY_HASH, 1128 .local_hash.filter_hash = EMPTY_HASH, 1129 INIT_OPS_HASH(global_ops) 1130 .flags = FTRACE_OPS_FL_RECURSION_SAFE | 1131 FTRACE_OPS_FL_INITIALIZED | 1132 FTRACE_OPS_FL_PID, 1133 }; 1134 1135 /* 1136 * This is used by __kernel_text_address() to return true if the 1137 * address is on a dynamically allocated trampoline that would 1138 * not return true for either core_kernel_text() or 1139 * is_module_text_address(). 1140 */ 1141 bool is_ftrace_trampoline(unsigned long addr) 1142 { 1143 struct ftrace_ops *op; 1144 bool ret = false; 1145 1146 /* 1147 * Some of the ops may be dynamically allocated, 1148 * they are freed after a synchronize_sched(). 1149 */ 1150 preempt_disable_notrace(); 1151 1152 do_for_each_ftrace_op(op, ftrace_ops_list) { 1153 /* 1154 * This is to check for dynamically allocated trampolines. 1155 * Trampolines that are in kernel text will have 1156 * core_kernel_text() return true. 1157 */ 1158 if (op->trampoline && op->trampoline_size) 1159 if (addr >= op->trampoline && 1160 addr < op->trampoline + op->trampoline_size) { 1161 ret = true; 1162 goto out; 1163 } 1164 } while_for_each_ftrace_op(op); 1165 1166 out: 1167 preempt_enable_notrace(); 1168 1169 return ret; 1170 } 1171 1172 struct ftrace_page { 1173 struct ftrace_page *next; 1174 struct dyn_ftrace *records; 1175 int index; 1176 int size; 1177 }; 1178 1179 #define ENTRY_SIZE sizeof(struct dyn_ftrace) 1180 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE) 1181 1182 /* estimate from running different kernels */ 1183 #define NR_TO_INIT 10000 1184 1185 static struct ftrace_page *ftrace_pages_start; 1186 static struct ftrace_page *ftrace_pages; 1187 1188 static __always_inline unsigned long 1189 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip) 1190 { 1191 if (hash->size_bits > 0) 1192 return hash_long(ip, hash->size_bits); 1193 1194 return 0; 1195 } 1196 1197 /* Only use this function if ftrace_hash_empty() has already been tested */ 1198 static __always_inline struct ftrace_func_entry * 1199 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip) 1200 { 1201 unsigned long key; 1202 struct ftrace_func_entry *entry; 1203 struct hlist_head *hhd; 1204 1205 key = ftrace_hash_key(hash, ip); 1206 hhd = &hash->buckets[key]; 1207 1208 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) { 1209 if (entry->ip == ip) 1210 return entry; 1211 } 1212 return NULL; 1213 } 1214 1215 /** 1216 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash 1217 * @hash: The hash to look at 1218 * @ip: The instruction pointer to test 1219 * 1220 * Search a given @hash to see if a given instruction pointer (@ip) 1221 * exists in it. 1222 * 1223 * Returns the entry that holds the @ip if found. NULL otherwise. 1224 */ 1225 struct ftrace_func_entry * 1226 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip) 1227 { 1228 if (ftrace_hash_empty(hash)) 1229 return NULL; 1230 1231 return __ftrace_lookup_ip(hash, ip); 1232 } 1233 1234 static void __add_hash_entry(struct ftrace_hash *hash, 1235 struct ftrace_func_entry *entry) 1236 { 1237 struct hlist_head *hhd; 1238 unsigned long key; 1239 1240 key = ftrace_hash_key(hash, entry->ip); 1241 hhd = &hash->buckets[key]; 1242 hlist_add_head(&entry->hlist, hhd); 1243 hash->count++; 1244 } 1245 1246 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip) 1247 { 1248 struct ftrace_func_entry *entry; 1249 1250 entry = kmalloc(sizeof(*entry), GFP_KERNEL); 1251 if (!entry) 1252 return -ENOMEM; 1253 1254 entry->ip = ip; 1255 __add_hash_entry(hash, entry); 1256 1257 return 0; 1258 } 1259 1260 static void 1261 free_hash_entry(struct ftrace_hash *hash, 1262 struct ftrace_func_entry *entry) 1263 { 1264 hlist_del(&entry->hlist); 1265 kfree(entry); 1266 hash->count--; 1267 } 1268 1269 static void 1270 remove_hash_entry(struct ftrace_hash *hash, 1271 struct ftrace_func_entry *entry) 1272 { 1273 hlist_del_rcu(&entry->hlist); 1274 hash->count--; 1275 } 1276 1277 static void ftrace_hash_clear(struct ftrace_hash *hash) 1278 { 1279 struct hlist_head *hhd; 1280 struct hlist_node *tn; 1281 struct ftrace_func_entry *entry; 1282 int size = 1 << hash->size_bits; 1283 int i; 1284 1285 if (!hash->count) 1286 return; 1287 1288 for (i = 0; i < size; i++) { 1289 hhd = &hash->buckets[i]; 1290 hlist_for_each_entry_safe(entry, tn, hhd, hlist) 1291 free_hash_entry(hash, entry); 1292 } 1293 FTRACE_WARN_ON(hash->count); 1294 } 1295 1296 static void free_ftrace_hash(struct ftrace_hash *hash) 1297 { 1298 if (!hash || hash == EMPTY_HASH) 1299 return; 1300 ftrace_hash_clear(hash); 1301 kfree(hash->buckets); 1302 kfree(hash); 1303 } 1304 1305 static void __free_ftrace_hash_rcu(struct rcu_head *rcu) 1306 { 1307 struct ftrace_hash *hash; 1308 1309 hash = container_of(rcu, struct ftrace_hash, rcu); 1310 free_ftrace_hash(hash); 1311 } 1312 1313 static void free_ftrace_hash_rcu(struct ftrace_hash *hash) 1314 { 1315 if (!hash || hash == EMPTY_HASH) 1316 return; 1317 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu); 1318 } 1319 1320 void ftrace_free_filter(struct ftrace_ops *ops) 1321 { 1322 ftrace_ops_init(ops); 1323 free_ftrace_hash(ops->func_hash->filter_hash); 1324 free_ftrace_hash(ops->func_hash->notrace_hash); 1325 } 1326 1327 static struct ftrace_hash *alloc_ftrace_hash(int size_bits) 1328 { 1329 struct ftrace_hash *hash; 1330 int size; 1331 1332 hash = kzalloc(sizeof(*hash), GFP_KERNEL); 1333 if (!hash) 1334 return NULL; 1335 1336 size = 1 << size_bits; 1337 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL); 1338 1339 if (!hash->buckets) { 1340 kfree(hash); 1341 return NULL; 1342 } 1343 1344 hash->size_bits = size_bits; 1345 1346 return hash; 1347 } 1348 1349 static struct ftrace_hash * 1350 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash) 1351 { 1352 struct ftrace_func_entry *entry; 1353 struct ftrace_hash *new_hash; 1354 int size; 1355 int ret; 1356 int i; 1357 1358 new_hash = alloc_ftrace_hash(size_bits); 1359 if (!new_hash) 1360 return NULL; 1361 1362 /* Empty hash? */ 1363 if (ftrace_hash_empty(hash)) 1364 return new_hash; 1365 1366 size = 1 << hash->size_bits; 1367 for (i = 0; i < size; i++) { 1368 hlist_for_each_entry(entry, &hash->buckets[i], hlist) { 1369 ret = add_hash_entry(new_hash, entry->ip); 1370 if (ret < 0) 1371 goto free_hash; 1372 } 1373 } 1374 1375 FTRACE_WARN_ON(new_hash->count != hash->count); 1376 1377 return new_hash; 1378 1379 free_hash: 1380 free_ftrace_hash(new_hash); 1381 return NULL; 1382 } 1383 1384 static void 1385 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash); 1386 static void 1387 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash); 1388 1389 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops, 1390 struct ftrace_hash *new_hash); 1391 1392 static struct ftrace_hash * 1393 __ftrace_hash_move(struct ftrace_hash *src) 1394 { 1395 struct ftrace_func_entry *entry; 1396 struct hlist_node *tn; 1397 struct hlist_head *hhd; 1398 struct ftrace_hash *new_hash; 1399 int size = src->count; 1400 int bits = 0; 1401 int i; 1402 1403 /* 1404 * If the new source is empty, just return the empty_hash. 1405 */ 1406 if (!src->count) 1407 return EMPTY_HASH; 1408 1409 /* 1410 * Make the hash size about 1/2 the # found 1411 */ 1412 for (size /= 2; size; size >>= 1) 1413 bits++; 1414 1415 /* Don't allocate too much */ 1416 if (bits > FTRACE_HASH_MAX_BITS) 1417 bits = FTRACE_HASH_MAX_BITS; 1418 1419 new_hash = alloc_ftrace_hash(bits); 1420 if (!new_hash) 1421 return NULL; 1422 1423 size = 1 << src->size_bits; 1424 for (i = 0; i < size; i++) { 1425 hhd = &src->buckets[i]; 1426 hlist_for_each_entry_safe(entry, tn, hhd, hlist) { 1427 remove_hash_entry(src, entry); 1428 __add_hash_entry(new_hash, entry); 1429 } 1430 } 1431 1432 return new_hash; 1433 } 1434 1435 static int 1436 ftrace_hash_move(struct ftrace_ops *ops, int enable, 1437 struct ftrace_hash **dst, struct ftrace_hash *src) 1438 { 1439 struct ftrace_hash *new_hash; 1440 int ret; 1441 1442 /* Reject setting notrace hash on IPMODIFY ftrace_ops */ 1443 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable) 1444 return -EINVAL; 1445 1446 new_hash = __ftrace_hash_move(src); 1447 if (!new_hash) 1448 return -ENOMEM; 1449 1450 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */ 1451 if (enable) { 1452 /* IPMODIFY should be updated only when filter_hash updating */ 1453 ret = ftrace_hash_ipmodify_update(ops, new_hash); 1454 if (ret < 0) { 1455 free_ftrace_hash(new_hash); 1456 return ret; 1457 } 1458 } 1459 1460 /* 1461 * Remove the current set, update the hash and add 1462 * them back. 1463 */ 1464 ftrace_hash_rec_disable_modify(ops, enable); 1465 1466 rcu_assign_pointer(*dst, new_hash); 1467 1468 ftrace_hash_rec_enable_modify(ops, enable); 1469 1470 return 0; 1471 } 1472 1473 static bool hash_contains_ip(unsigned long ip, 1474 struct ftrace_ops_hash *hash) 1475 { 1476 /* 1477 * The function record is a match if it exists in the filter 1478 * hash and not in the notrace hash. Note, an emty hash is 1479 * considered a match for the filter hash, but an empty 1480 * notrace hash is considered not in the notrace hash. 1481 */ 1482 return (ftrace_hash_empty(hash->filter_hash) || 1483 __ftrace_lookup_ip(hash->filter_hash, ip)) && 1484 (ftrace_hash_empty(hash->notrace_hash) || 1485 !__ftrace_lookup_ip(hash->notrace_hash, ip)); 1486 } 1487 1488 /* 1489 * Test the hashes for this ops to see if we want to call 1490 * the ops->func or not. 1491 * 1492 * It's a match if the ip is in the ops->filter_hash or 1493 * the filter_hash does not exist or is empty, 1494 * AND 1495 * the ip is not in the ops->notrace_hash. 1496 * 1497 * This needs to be called with preemption disabled as 1498 * the hashes are freed with call_rcu_sched(). 1499 */ 1500 static int 1501 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) 1502 { 1503 struct ftrace_ops_hash hash; 1504 int ret; 1505 1506 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 1507 /* 1508 * There's a small race when adding ops that the ftrace handler 1509 * that wants regs, may be called without them. We can not 1510 * allow that handler to be called if regs is NULL. 1511 */ 1512 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS)) 1513 return 0; 1514 #endif 1515 1516 hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash); 1517 hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash); 1518 1519 if (hash_contains_ip(ip, &hash)) 1520 ret = 1; 1521 else 1522 ret = 0; 1523 1524 return ret; 1525 } 1526 1527 /* 1528 * This is a double for. Do not use 'break' to break out of the loop, 1529 * you must use a goto. 1530 */ 1531 #define do_for_each_ftrace_rec(pg, rec) \ 1532 for (pg = ftrace_pages_start; pg; pg = pg->next) { \ 1533 int _____i; \ 1534 for (_____i = 0; _____i < pg->index; _____i++) { \ 1535 rec = &pg->records[_____i]; 1536 1537 #define while_for_each_ftrace_rec() \ 1538 } \ 1539 } 1540 1541 1542 static int ftrace_cmp_recs(const void *a, const void *b) 1543 { 1544 const struct dyn_ftrace *key = a; 1545 const struct dyn_ftrace *rec = b; 1546 1547 if (key->flags < rec->ip) 1548 return -1; 1549 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE) 1550 return 1; 1551 return 0; 1552 } 1553 1554 /** 1555 * ftrace_location_range - return the first address of a traced location 1556 * if it touches the given ip range 1557 * @start: start of range to search. 1558 * @end: end of range to search (inclusive). @end points to the last byte 1559 * to check. 1560 * 1561 * Returns rec->ip if the related ftrace location is a least partly within 1562 * the given address range. That is, the first address of the instruction 1563 * that is either a NOP or call to the function tracer. It checks the ftrace 1564 * internal tables to determine if the address belongs or not. 1565 */ 1566 unsigned long ftrace_location_range(unsigned long start, unsigned long end) 1567 { 1568 struct ftrace_page *pg; 1569 struct dyn_ftrace *rec; 1570 struct dyn_ftrace key; 1571 1572 key.ip = start; 1573 key.flags = end; /* overload flags, as it is unsigned long */ 1574 1575 for (pg = ftrace_pages_start; pg; pg = pg->next) { 1576 if (end < pg->records[0].ip || 1577 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE)) 1578 continue; 1579 rec = bsearch(&key, pg->records, pg->index, 1580 sizeof(struct dyn_ftrace), 1581 ftrace_cmp_recs); 1582 if (rec) 1583 return rec->ip; 1584 } 1585 1586 return 0; 1587 } 1588 1589 /** 1590 * ftrace_location - return true if the ip giving is a traced location 1591 * @ip: the instruction pointer to check 1592 * 1593 * Returns rec->ip if @ip given is a pointer to a ftrace location. 1594 * That is, the instruction that is either a NOP or call to 1595 * the function tracer. It checks the ftrace internal tables to 1596 * determine if the address belongs or not. 1597 */ 1598 unsigned long ftrace_location(unsigned long ip) 1599 { 1600 return ftrace_location_range(ip, ip); 1601 } 1602 1603 /** 1604 * ftrace_text_reserved - return true if range contains an ftrace location 1605 * @start: start of range to search 1606 * @end: end of range to search (inclusive). @end points to the last byte to check. 1607 * 1608 * Returns 1 if @start and @end contains a ftrace location. 1609 * That is, the instruction that is either a NOP or call to 1610 * the function tracer. It checks the ftrace internal tables to 1611 * determine if the address belongs or not. 1612 */ 1613 int ftrace_text_reserved(const void *start, const void *end) 1614 { 1615 unsigned long ret; 1616 1617 ret = ftrace_location_range((unsigned long)start, 1618 (unsigned long)end); 1619 1620 return (int)!!ret; 1621 } 1622 1623 /* Test if ops registered to this rec needs regs */ 1624 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec) 1625 { 1626 struct ftrace_ops *ops; 1627 bool keep_regs = false; 1628 1629 for (ops = ftrace_ops_list; 1630 ops != &ftrace_list_end; ops = ops->next) { 1631 /* pass rec in as regs to have non-NULL val */ 1632 if (ftrace_ops_test(ops, rec->ip, rec)) { 1633 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) { 1634 keep_regs = true; 1635 break; 1636 } 1637 } 1638 } 1639 1640 return keep_regs; 1641 } 1642 1643 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops, 1644 int filter_hash, 1645 bool inc) 1646 { 1647 struct ftrace_hash *hash; 1648 struct ftrace_hash *other_hash; 1649 struct ftrace_page *pg; 1650 struct dyn_ftrace *rec; 1651 bool update = false; 1652 int count = 0; 1653 int all = 0; 1654 1655 /* Only update if the ops has been registered */ 1656 if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) 1657 return false; 1658 1659 /* 1660 * In the filter_hash case: 1661 * If the count is zero, we update all records. 1662 * Otherwise we just update the items in the hash. 1663 * 1664 * In the notrace_hash case: 1665 * We enable the update in the hash. 1666 * As disabling notrace means enabling the tracing, 1667 * and enabling notrace means disabling, the inc variable 1668 * gets inversed. 1669 */ 1670 if (filter_hash) { 1671 hash = ops->func_hash->filter_hash; 1672 other_hash = ops->func_hash->notrace_hash; 1673 if (ftrace_hash_empty(hash)) 1674 all = 1; 1675 } else { 1676 inc = !inc; 1677 hash = ops->func_hash->notrace_hash; 1678 other_hash = ops->func_hash->filter_hash; 1679 /* 1680 * If the notrace hash has no items, 1681 * then there's nothing to do. 1682 */ 1683 if (ftrace_hash_empty(hash)) 1684 return false; 1685 } 1686 1687 do_for_each_ftrace_rec(pg, rec) { 1688 int in_other_hash = 0; 1689 int in_hash = 0; 1690 int match = 0; 1691 1692 if (rec->flags & FTRACE_FL_DISABLED) 1693 continue; 1694 1695 if (all) { 1696 /* 1697 * Only the filter_hash affects all records. 1698 * Update if the record is not in the notrace hash. 1699 */ 1700 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip)) 1701 match = 1; 1702 } else { 1703 in_hash = !!ftrace_lookup_ip(hash, rec->ip); 1704 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip); 1705 1706 /* 1707 * If filter_hash is set, we want to match all functions 1708 * that are in the hash but not in the other hash. 1709 * 1710 * If filter_hash is not set, then we are decrementing. 1711 * That means we match anything that is in the hash 1712 * and also in the other_hash. That is, we need to turn 1713 * off functions in the other hash because they are disabled 1714 * by this hash. 1715 */ 1716 if (filter_hash && in_hash && !in_other_hash) 1717 match = 1; 1718 else if (!filter_hash && in_hash && 1719 (in_other_hash || ftrace_hash_empty(other_hash))) 1720 match = 1; 1721 } 1722 if (!match) 1723 continue; 1724 1725 if (inc) { 1726 rec->flags++; 1727 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX)) 1728 return false; 1729 1730 /* 1731 * If there's only a single callback registered to a 1732 * function, and the ops has a trampoline registered 1733 * for it, then we can call it directly. 1734 */ 1735 if (ftrace_rec_count(rec) == 1 && ops->trampoline) 1736 rec->flags |= FTRACE_FL_TRAMP; 1737 else 1738 /* 1739 * If we are adding another function callback 1740 * to this function, and the previous had a 1741 * custom trampoline in use, then we need to go 1742 * back to the default trampoline. 1743 */ 1744 rec->flags &= ~FTRACE_FL_TRAMP; 1745 1746 /* 1747 * If any ops wants regs saved for this function 1748 * then all ops will get saved regs. 1749 */ 1750 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) 1751 rec->flags |= FTRACE_FL_REGS; 1752 } else { 1753 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0)) 1754 return false; 1755 rec->flags--; 1756 1757 /* 1758 * If the rec had REGS enabled and the ops that is 1759 * being removed had REGS set, then see if there is 1760 * still any ops for this record that wants regs. 1761 * If not, we can stop recording them. 1762 */ 1763 if (ftrace_rec_count(rec) > 0 && 1764 rec->flags & FTRACE_FL_REGS && 1765 ops->flags & FTRACE_OPS_FL_SAVE_REGS) { 1766 if (!test_rec_ops_needs_regs(rec)) 1767 rec->flags &= ~FTRACE_FL_REGS; 1768 } 1769 1770 /* 1771 * If the rec had TRAMP enabled, then it needs to 1772 * be cleared. As TRAMP can only be enabled iff 1773 * there is only a single ops attached to it. 1774 * In otherwords, always disable it on decrementing. 1775 * In the future, we may set it if rec count is 1776 * decremented to one, and the ops that is left 1777 * has a trampoline. 1778 */ 1779 rec->flags &= ~FTRACE_FL_TRAMP; 1780 1781 /* 1782 * flags will be cleared in ftrace_check_record() 1783 * if rec count is zero. 1784 */ 1785 } 1786 count++; 1787 1788 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */ 1789 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE; 1790 1791 /* Shortcut, if we handled all records, we are done. */ 1792 if (!all && count == hash->count) 1793 return update; 1794 } while_for_each_ftrace_rec(); 1795 1796 return update; 1797 } 1798 1799 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops, 1800 int filter_hash) 1801 { 1802 return __ftrace_hash_rec_update(ops, filter_hash, 0); 1803 } 1804 1805 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops, 1806 int filter_hash) 1807 { 1808 return __ftrace_hash_rec_update(ops, filter_hash, 1); 1809 } 1810 1811 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops, 1812 int filter_hash, int inc) 1813 { 1814 struct ftrace_ops *op; 1815 1816 __ftrace_hash_rec_update(ops, filter_hash, inc); 1817 1818 if (ops->func_hash != &global_ops.local_hash) 1819 return; 1820 1821 /* 1822 * If the ops shares the global_ops hash, then we need to update 1823 * all ops that are enabled and use this hash. 1824 */ 1825 do_for_each_ftrace_op(op, ftrace_ops_list) { 1826 /* Already done */ 1827 if (op == ops) 1828 continue; 1829 if (op->func_hash == &global_ops.local_hash) 1830 __ftrace_hash_rec_update(op, filter_hash, inc); 1831 } while_for_each_ftrace_op(op); 1832 } 1833 1834 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, 1835 int filter_hash) 1836 { 1837 ftrace_hash_rec_update_modify(ops, filter_hash, 0); 1838 } 1839 1840 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, 1841 int filter_hash) 1842 { 1843 ftrace_hash_rec_update_modify(ops, filter_hash, 1); 1844 } 1845 1846 /* 1847 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK 1848 * or no-needed to update, -EBUSY if it detects a conflict of the flag 1849 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs. 1850 * Note that old_hash and new_hash has below meanings 1851 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected) 1852 * - If the hash is EMPTY_HASH, it hits nothing 1853 * - Anything else hits the recs which match the hash entries. 1854 */ 1855 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops, 1856 struct ftrace_hash *old_hash, 1857 struct ftrace_hash *new_hash) 1858 { 1859 struct ftrace_page *pg; 1860 struct dyn_ftrace *rec, *end = NULL; 1861 int in_old, in_new; 1862 1863 /* Only update if the ops has been registered */ 1864 if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) 1865 return 0; 1866 1867 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY)) 1868 return 0; 1869 1870 /* 1871 * Since the IPMODIFY is a very address sensitive action, we do not 1872 * allow ftrace_ops to set all functions to new hash. 1873 */ 1874 if (!new_hash || !old_hash) 1875 return -EINVAL; 1876 1877 /* Update rec->flags */ 1878 do_for_each_ftrace_rec(pg, rec) { 1879 1880 if (rec->flags & FTRACE_FL_DISABLED) 1881 continue; 1882 1883 /* We need to update only differences of filter_hash */ 1884 in_old = !!ftrace_lookup_ip(old_hash, rec->ip); 1885 in_new = !!ftrace_lookup_ip(new_hash, rec->ip); 1886 if (in_old == in_new) 1887 continue; 1888 1889 if (in_new) { 1890 /* New entries must ensure no others are using it */ 1891 if (rec->flags & FTRACE_FL_IPMODIFY) 1892 goto rollback; 1893 rec->flags |= FTRACE_FL_IPMODIFY; 1894 } else /* Removed entry */ 1895 rec->flags &= ~FTRACE_FL_IPMODIFY; 1896 } while_for_each_ftrace_rec(); 1897 1898 return 0; 1899 1900 rollback: 1901 end = rec; 1902 1903 /* Roll back what we did above */ 1904 do_for_each_ftrace_rec(pg, rec) { 1905 1906 if (rec->flags & FTRACE_FL_DISABLED) 1907 continue; 1908 1909 if (rec == end) 1910 goto err_out; 1911 1912 in_old = !!ftrace_lookup_ip(old_hash, rec->ip); 1913 in_new = !!ftrace_lookup_ip(new_hash, rec->ip); 1914 if (in_old == in_new) 1915 continue; 1916 1917 if (in_new) 1918 rec->flags &= ~FTRACE_FL_IPMODIFY; 1919 else 1920 rec->flags |= FTRACE_FL_IPMODIFY; 1921 } while_for_each_ftrace_rec(); 1922 1923 err_out: 1924 return -EBUSY; 1925 } 1926 1927 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops) 1928 { 1929 struct ftrace_hash *hash = ops->func_hash->filter_hash; 1930 1931 if (ftrace_hash_empty(hash)) 1932 hash = NULL; 1933 1934 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash); 1935 } 1936 1937 /* Disabling always succeeds */ 1938 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops) 1939 { 1940 struct ftrace_hash *hash = ops->func_hash->filter_hash; 1941 1942 if (ftrace_hash_empty(hash)) 1943 hash = NULL; 1944 1945 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH); 1946 } 1947 1948 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops, 1949 struct ftrace_hash *new_hash) 1950 { 1951 struct ftrace_hash *old_hash = ops->func_hash->filter_hash; 1952 1953 if (ftrace_hash_empty(old_hash)) 1954 old_hash = NULL; 1955 1956 if (ftrace_hash_empty(new_hash)) 1957 new_hash = NULL; 1958 1959 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash); 1960 } 1961 1962 static void print_ip_ins(const char *fmt, const unsigned char *p) 1963 { 1964 int i; 1965 1966 printk(KERN_CONT "%s", fmt); 1967 1968 for (i = 0; i < MCOUNT_INSN_SIZE; i++) 1969 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]); 1970 } 1971 1972 static struct ftrace_ops * 1973 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec); 1974 static struct ftrace_ops * 1975 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops); 1976 1977 enum ftrace_bug_type ftrace_bug_type; 1978 const void *ftrace_expected; 1979 1980 static void print_bug_type(void) 1981 { 1982 switch (ftrace_bug_type) { 1983 case FTRACE_BUG_UNKNOWN: 1984 break; 1985 case FTRACE_BUG_INIT: 1986 pr_info("Initializing ftrace call sites\n"); 1987 break; 1988 case FTRACE_BUG_NOP: 1989 pr_info("Setting ftrace call site to NOP\n"); 1990 break; 1991 case FTRACE_BUG_CALL: 1992 pr_info("Setting ftrace call site to call ftrace function\n"); 1993 break; 1994 case FTRACE_BUG_UPDATE: 1995 pr_info("Updating ftrace call site to call a different ftrace function\n"); 1996 break; 1997 } 1998 } 1999 2000 /** 2001 * ftrace_bug - report and shutdown function tracer 2002 * @failed: The failed type (EFAULT, EINVAL, EPERM) 2003 * @rec: The record that failed 2004 * 2005 * The arch code that enables or disables the function tracing 2006 * can call ftrace_bug() when it has detected a problem in 2007 * modifying the code. @failed should be one of either: 2008 * EFAULT - if the problem happens on reading the @ip address 2009 * EINVAL - if what is read at @ip is not what was expected 2010 * EPERM - if the problem happens on writting to the @ip address 2011 */ 2012 void ftrace_bug(int failed, struct dyn_ftrace *rec) 2013 { 2014 unsigned long ip = rec ? rec->ip : 0; 2015 2016 switch (failed) { 2017 case -EFAULT: 2018 FTRACE_WARN_ON_ONCE(1); 2019 pr_info("ftrace faulted on modifying "); 2020 print_ip_sym(ip); 2021 break; 2022 case -EINVAL: 2023 FTRACE_WARN_ON_ONCE(1); 2024 pr_info("ftrace failed to modify "); 2025 print_ip_sym(ip); 2026 print_ip_ins(" actual: ", (unsigned char *)ip); 2027 pr_cont("\n"); 2028 if (ftrace_expected) { 2029 print_ip_ins(" expected: ", ftrace_expected); 2030 pr_cont("\n"); 2031 } 2032 break; 2033 case -EPERM: 2034 FTRACE_WARN_ON_ONCE(1); 2035 pr_info("ftrace faulted on writing "); 2036 print_ip_sym(ip); 2037 break; 2038 default: 2039 FTRACE_WARN_ON_ONCE(1); 2040 pr_info("ftrace faulted on unknown error "); 2041 print_ip_sym(ip); 2042 } 2043 print_bug_type(); 2044 if (rec) { 2045 struct ftrace_ops *ops = NULL; 2046 2047 pr_info("ftrace record flags: %lx\n", rec->flags); 2048 pr_cont(" (%ld)%s", ftrace_rec_count(rec), 2049 rec->flags & FTRACE_FL_REGS ? " R" : " "); 2050 if (rec->flags & FTRACE_FL_TRAMP_EN) { 2051 ops = ftrace_find_tramp_ops_any(rec); 2052 if (ops) { 2053 do { 2054 pr_cont("\ttramp: %pS (%pS)", 2055 (void *)ops->trampoline, 2056 (void *)ops->func); 2057 ops = ftrace_find_tramp_ops_next(rec, ops); 2058 } while (ops); 2059 } else 2060 pr_cont("\ttramp: ERROR!"); 2061 2062 } 2063 ip = ftrace_get_addr_curr(rec); 2064 pr_cont("\n expected tramp: %lx\n", ip); 2065 } 2066 } 2067 2068 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) 2069 { 2070 unsigned long flag = 0UL; 2071 2072 ftrace_bug_type = FTRACE_BUG_UNKNOWN; 2073 2074 if (rec->flags & FTRACE_FL_DISABLED) 2075 return FTRACE_UPDATE_IGNORE; 2076 2077 /* 2078 * If we are updating calls: 2079 * 2080 * If the record has a ref count, then we need to enable it 2081 * because someone is using it. 2082 * 2083 * Otherwise we make sure its disabled. 2084 * 2085 * If we are disabling calls, then disable all records that 2086 * are enabled. 2087 */ 2088 if (enable && ftrace_rec_count(rec)) 2089 flag = FTRACE_FL_ENABLED; 2090 2091 /* 2092 * If enabling and the REGS flag does not match the REGS_EN, or 2093 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore 2094 * this record. Set flags to fail the compare against ENABLED. 2095 */ 2096 if (flag) { 2097 if (!(rec->flags & FTRACE_FL_REGS) != 2098 !(rec->flags & FTRACE_FL_REGS_EN)) 2099 flag |= FTRACE_FL_REGS; 2100 2101 if (!(rec->flags & FTRACE_FL_TRAMP) != 2102 !(rec->flags & FTRACE_FL_TRAMP_EN)) 2103 flag |= FTRACE_FL_TRAMP; 2104 } 2105 2106 /* If the state of this record hasn't changed, then do nothing */ 2107 if ((rec->flags & FTRACE_FL_ENABLED) == flag) 2108 return FTRACE_UPDATE_IGNORE; 2109 2110 if (flag) { 2111 /* Save off if rec is being enabled (for return value) */ 2112 flag ^= rec->flags & FTRACE_FL_ENABLED; 2113 2114 if (update) { 2115 rec->flags |= FTRACE_FL_ENABLED; 2116 if (flag & FTRACE_FL_REGS) { 2117 if (rec->flags & FTRACE_FL_REGS) 2118 rec->flags |= FTRACE_FL_REGS_EN; 2119 else 2120 rec->flags &= ~FTRACE_FL_REGS_EN; 2121 } 2122 if (flag & FTRACE_FL_TRAMP) { 2123 if (rec->flags & FTRACE_FL_TRAMP) 2124 rec->flags |= FTRACE_FL_TRAMP_EN; 2125 else 2126 rec->flags &= ~FTRACE_FL_TRAMP_EN; 2127 } 2128 } 2129 2130 /* 2131 * If this record is being updated from a nop, then 2132 * return UPDATE_MAKE_CALL. 2133 * Otherwise, 2134 * return UPDATE_MODIFY_CALL to tell the caller to convert 2135 * from the save regs, to a non-save regs function or 2136 * vice versa, or from a trampoline call. 2137 */ 2138 if (flag & FTRACE_FL_ENABLED) { 2139 ftrace_bug_type = FTRACE_BUG_CALL; 2140 return FTRACE_UPDATE_MAKE_CALL; 2141 } 2142 2143 ftrace_bug_type = FTRACE_BUG_UPDATE; 2144 return FTRACE_UPDATE_MODIFY_CALL; 2145 } 2146 2147 if (update) { 2148 /* If there's no more users, clear all flags */ 2149 if (!ftrace_rec_count(rec)) 2150 rec->flags = 0; 2151 else 2152 /* 2153 * Just disable the record, but keep the ops TRAMP 2154 * and REGS states. The _EN flags must be disabled though. 2155 */ 2156 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN | 2157 FTRACE_FL_REGS_EN); 2158 } 2159 2160 ftrace_bug_type = FTRACE_BUG_NOP; 2161 return FTRACE_UPDATE_MAKE_NOP; 2162 } 2163 2164 /** 2165 * ftrace_update_record, set a record that now is tracing or not 2166 * @rec: the record to update 2167 * @enable: set to 1 if the record is tracing, zero to force disable 2168 * 2169 * The records that represent all functions that can be traced need 2170 * to be updated when tracing has been enabled. 2171 */ 2172 int ftrace_update_record(struct dyn_ftrace *rec, int enable) 2173 { 2174 return ftrace_check_record(rec, enable, 1); 2175 } 2176 2177 /** 2178 * ftrace_test_record, check if the record has been enabled or not 2179 * @rec: the record to test 2180 * @enable: set to 1 to check if enabled, 0 if it is disabled 2181 * 2182 * The arch code may need to test if a record is already set to 2183 * tracing to determine how to modify the function code that it 2184 * represents. 2185 */ 2186 int ftrace_test_record(struct dyn_ftrace *rec, int enable) 2187 { 2188 return ftrace_check_record(rec, enable, 0); 2189 } 2190 2191 static struct ftrace_ops * 2192 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec) 2193 { 2194 struct ftrace_ops *op; 2195 unsigned long ip = rec->ip; 2196 2197 do_for_each_ftrace_op(op, ftrace_ops_list) { 2198 2199 if (!op->trampoline) 2200 continue; 2201 2202 if (hash_contains_ip(ip, op->func_hash)) 2203 return op; 2204 } while_for_each_ftrace_op(op); 2205 2206 return NULL; 2207 } 2208 2209 static struct ftrace_ops * 2210 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, 2211 struct ftrace_ops *op) 2212 { 2213 unsigned long ip = rec->ip; 2214 2215 while_for_each_ftrace_op(op) { 2216 2217 if (!op->trampoline) 2218 continue; 2219 2220 if (hash_contains_ip(ip, op->func_hash)) 2221 return op; 2222 } 2223 2224 return NULL; 2225 } 2226 2227 static struct ftrace_ops * 2228 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec) 2229 { 2230 struct ftrace_ops *op; 2231 unsigned long ip = rec->ip; 2232 2233 /* 2234 * Need to check removed ops first. 2235 * If they are being removed, and this rec has a tramp, 2236 * and this rec is in the ops list, then it would be the 2237 * one with the tramp. 2238 */ 2239 if (removed_ops) { 2240 if (hash_contains_ip(ip, &removed_ops->old_hash)) 2241 return removed_ops; 2242 } 2243 2244 /* 2245 * Need to find the current trampoline for a rec. 2246 * Now, a trampoline is only attached to a rec if there 2247 * was a single 'ops' attached to it. But this can be called 2248 * when we are adding another op to the rec or removing the 2249 * current one. Thus, if the op is being added, we can 2250 * ignore it because it hasn't attached itself to the rec 2251 * yet. 2252 * 2253 * If an ops is being modified (hooking to different functions) 2254 * then we don't care about the new functions that are being 2255 * added, just the old ones (that are probably being removed). 2256 * 2257 * If we are adding an ops to a function that already is using 2258 * a trampoline, it needs to be removed (trampolines are only 2259 * for single ops connected), then an ops that is not being 2260 * modified also needs to be checked. 2261 */ 2262 do_for_each_ftrace_op(op, ftrace_ops_list) { 2263 2264 if (!op->trampoline) 2265 continue; 2266 2267 /* 2268 * If the ops is being added, it hasn't gotten to 2269 * the point to be removed from this tree yet. 2270 */ 2271 if (op->flags & FTRACE_OPS_FL_ADDING) 2272 continue; 2273 2274 2275 /* 2276 * If the ops is being modified and is in the old 2277 * hash, then it is probably being removed from this 2278 * function. 2279 */ 2280 if ((op->flags & FTRACE_OPS_FL_MODIFYING) && 2281 hash_contains_ip(ip, &op->old_hash)) 2282 return op; 2283 /* 2284 * If the ops is not being added or modified, and it's 2285 * in its normal filter hash, then this must be the one 2286 * we want! 2287 */ 2288 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) && 2289 hash_contains_ip(ip, op->func_hash)) 2290 return op; 2291 2292 } while_for_each_ftrace_op(op); 2293 2294 return NULL; 2295 } 2296 2297 static struct ftrace_ops * 2298 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec) 2299 { 2300 struct ftrace_ops *op; 2301 unsigned long ip = rec->ip; 2302 2303 do_for_each_ftrace_op(op, ftrace_ops_list) { 2304 /* pass rec in as regs to have non-NULL val */ 2305 if (hash_contains_ip(ip, op->func_hash)) 2306 return op; 2307 } while_for_each_ftrace_op(op); 2308 2309 return NULL; 2310 } 2311 2312 /** 2313 * ftrace_get_addr_new - Get the call address to set to 2314 * @rec: The ftrace record descriptor 2315 * 2316 * If the record has the FTRACE_FL_REGS set, that means that it 2317 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS 2318 * is not not set, then it wants to convert to the normal callback. 2319 * 2320 * Returns the address of the trampoline to set to 2321 */ 2322 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) 2323 { 2324 struct ftrace_ops *ops; 2325 2326 /* Trampolines take precedence over regs */ 2327 if (rec->flags & FTRACE_FL_TRAMP) { 2328 ops = ftrace_find_tramp_ops_new(rec); 2329 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) { 2330 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n", 2331 (void *)rec->ip, (void *)rec->ip, rec->flags); 2332 /* Ftrace is shutting down, return anything */ 2333 return (unsigned long)FTRACE_ADDR; 2334 } 2335 return ops->trampoline; 2336 } 2337 2338 if (rec->flags & FTRACE_FL_REGS) 2339 return (unsigned long)FTRACE_REGS_ADDR; 2340 else 2341 return (unsigned long)FTRACE_ADDR; 2342 } 2343 2344 /** 2345 * ftrace_get_addr_curr - Get the call address that is already there 2346 * @rec: The ftrace record descriptor 2347 * 2348 * The FTRACE_FL_REGS_EN is set when the record already points to 2349 * a function that saves all the regs. Basically the '_EN' version 2350 * represents the current state of the function. 2351 * 2352 * Returns the address of the trampoline that is currently being called 2353 */ 2354 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec) 2355 { 2356 struct ftrace_ops *ops; 2357 2358 /* Trampolines take precedence over regs */ 2359 if (rec->flags & FTRACE_FL_TRAMP_EN) { 2360 ops = ftrace_find_tramp_ops_curr(rec); 2361 if (FTRACE_WARN_ON(!ops)) { 2362 pr_warn("Bad trampoline accounting at: %p (%pS)\n", 2363 (void *)rec->ip, (void *)rec->ip); 2364 /* Ftrace is shutting down, return anything */ 2365 return (unsigned long)FTRACE_ADDR; 2366 } 2367 return ops->trampoline; 2368 } 2369 2370 if (rec->flags & FTRACE_FL_REGS_EN) 2371 return (unsigned long)FTRACE_REGS_ADDR; 2372 else 2373 return (unsigned long)FTRACE_ADDR; 2374 } 2375 2376 static int 2377 __ftrace_replace_code(struct dyn_ftrace *rec, int enable) 2378 { 2379 unsigned long ftrace_old_addr; 2380 unsigned long ftrace_addr; 2381 int ret; 2382 2383 ftrace_addr = ftrace_get_addr_new(rec); 2384 2385 /* This needs to be done before we call ftrace_update_record */ 2386 ftrace_old_addr = ftrace_get_addr_curr(rec); 2387 2388 ret = ftrace_update_record(rec, enable); 2389 2390 ftrace_bug_type = FTRACE_BUG_UNKNOWN; 2391 2392 switch (ret) { 2393 case FTRACE_UPDATE_IGNORE: 2394 return 0; 2395 2396 case FTRACE_UPDATE_MAKE_CALL: 2397 ftrace_bug_type = FTRACE_BUG_CALL; 2398 return ftrace_make_call(rec, ftrace_addr); 2399 2400 case FTRACE_UPDATE_MAKE_NOP: 2401 ftrace_bug_type = FTRACE_BUG_NOP; 2402 return ftrace_make_nop(NULL, rec, ftrace_old_addr); 2403 2404 case FTRACE_UPDATE_MODIFY_CALL: 2405 ftrace_bug_type = FTRACE_BUG_UPDATE; 2406 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr); 2407 } 2408 2409 return -1; /* unknow ftrace bug */ 2410 } 2411 2412 void __weak ftrace_replace_code(int enable) 2413 { 2414 struct dyn_ftrace *rec; 2415 struct ftrace_page *pg; 2416 int failed; 2417 2418 if (unlikely(ftrace_disabled)) 2419 return; 2420 2421 do_for_each_ftrace_rec(pg, rec) { 2422 2423 if (rec->flags & FTRACE_FL_DISABLED) 2424 continue; 2425 2426 failed = __ftrace_replace_code(rec, enable); 2427 if (failed) { 2428 ftrace_bug(failed, rec); 2429 /* Stop processing */ 2430 return; 2431 } 2432 } while_for_each_ftrace_rec(); 2433 } 2434 2435 struct ftrace_rec_iter { 2436 struct ftrace_page *pg; 2437 int index; 2438 }; 2439 2440 /** 2441 * ftrace_rec_iter_start, start up iterating over traced functions 2442 * 2443 * Returns an iterator handle that is used to iterate over all 2444 * the records that represent address locations where functions 2445 * are traced. 2446 * 2447 * May return NULL if no records are available. 2448 */ 2449 struct ftrace_rec_iter *ftrace_rec_iter_start(void) 2450 { 2451 /* 2452 * We only use a single iterator. 2453 * Protected by the ftrace_lock mutex. 2454 */ 2455 static struct ftrace_rec_iter ftrace_rec_iter; 2456 struct ftrace_rec_iter *iter = &ftrace_rec_iter; 2457 2458 iter->pg = ftrace_pages_start; 2459 iter->index = 0; 2460 2461 /* Could have empty pages */ 2462 while (iter->pg && !iter->pg->index) 2463 iter->pg = iter->pg->next; 2464 2465 if (!iter->pg) 2466 return NULL; 2467 2468 return iter; 2469 } 2470 2471 /** 2472 * ftrace_rec_iter_next, get the next record to process. 2473 * @iter: The handle to the iterator. 2474 * 2475 * Returns the next iterator after the given iterator @iter. 2476 */ 2477 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter) 2478 { 2479 iter->index++; 2480 2481 if (iter->index >= iter->pg->index) { 2482 iter->pg = iter->pg->next; 2483 iter->index = 0; 2484 2485 /* Could have empty pages */ 2486 while (iter->pg && !iter->pg->index) 2487 iter->pg = iter->pg->next; 2488 } 2489 2490 if (!iter->pg) 2491 return NULL; 2492 2493 return iter; 2494 } 2495 2496 /** 2497 * ftrace_rec_iter_record, get the record at the iterator location 2498 * @iter: The current iterator location 2499 * 2500 * Returns the record that the current @iter is at. 2501 */ 2502 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter) 2503 { 2504 return &iter->pg->records[iter->index]; 2505 } 2506 2507 static int 2508 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec) 2509 { 2510 int ret; 2511 2512 if (unlikely(ftrace_disabled)) 2513 return 0; 2514 2515 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR); 2516 if (ret) { 2517 ftrace_bug_type = FTRACE_BUG_INIT; 2518 ftrace_bug(ret, rec); 2519 return 0; 2520 } 2521 return 1; 2522 } 2523 2524 /* 2525 * archs can override this function if they must do something 2526 * before the modifying code is performed. 2527 */ 2528 int __weak ftrace_arch_code_modify_prepare(void) 2529 { 2530 return 0; 2531 } 2532 2533 /* 2534 * archs can override this function if they must do something 2535 * after the modifying code is performed. 2536 */ 2537 int __weak ftrace_arch_code_modify_post_process(void) 2538 { 2539 return 0; 2540 } 2541 2542 void ftrace_modify_all_code(int command) 2543 { 2544 int update = command & FTRACE_UPDATE_TRACE_FUNC; 2545 int err = 0; 2546 2547 /* 2548 * If the ftrace_caller calls a ftrace_ops func directly, 2549 * we need to make sure that it only traces functions it 2550 * expects to trace. When doing the switch of functions, 2551 * we need to update to the ftrace_ops_list_func first 2552 * before the transition between old and new calls are set, 2553 * as the ftrace_ops_list_func will check the ops hashes 2554 * to make sure the ops are having the right functions 2555 * traced. 2556 */ 2557 if (update) { 2558 err = ftrace_update_ftrace_func(ftrace_ops_list_func); 2559 if (FTRACE_WARN_ON(err)) 2560 return; 2561 } 2562 2563 if (command & FTRACE_UPDATE_CALLS) 2564 ftrace_replace_code(1); 2565 else if (command & FTRACE_DISABLE_CALLS) 2566 ftrace_replace_code(0); 2567 2568 if (update && ftrace_trace_function != ftrace_ops_list_func) { 2569 function_trace_op = set_function_trace_op; 2570 smp_wmb(); 2571 /* If irqs are disabled, we are in stop machine */ 2572 if (!irqs_disabled()) 2573 smp_call_function(ftrace_sync_ipi, NULL, 1); 2574 err = ftrace_update_ftrace_func(ftrace_trace_function); 2575 if (FTRACE_WARN_ON(err)) 2576 return; 2577 } 2578 2579 if (command & FTRACE_START_FUNC_RET) 2580 err = ftrace_enable_ftrace_graph_caller(); 2581 else if (command & FTRACE_STOP_FUNC_RET) 2582 err = ftrace_disable_ftrace_graph_caller(); 2583 FTRACE_WARN_ON(err); 2584 } 2585 2586 static int __ftrace_modify_code(void *data) 2587 { 2588 int *command = data; 2589 2590 ftrace_modify_all_code(*command); 2591 2592 return 0; 2593 } 2594 2595 /** 2596 * ftrace_run_stop_machine, go back to the stop machine method 2597 * @command: The command to tell ftrace what to do 2598 * 2599 * If an arch needs to fall back to the stop machine method, the 2600 * it can call this function. 2601 */ 2602 void ftrace_run_stop_machine(int command) 2603 { 2604 stop_machine(__ftrace_modify_code, &command, NULL); 2605 } 2606 2607 /** 2608 * arch_ftrace_update_code, modify the code to trace or not trace 2609 * @command: The command that needs to be done 2610 * 2611 * Archs can override this function if it does not need to 2612 * run stop_machine() to modify code. 2613 */ 2614 void __weak arch_ftrace_update_code(int command) 2615 { 2616 ftrace_run_stop_machine(command); 2617 } 2618 2619 static void ftrace_run_update_code(int command) 2620 { 2621 int ret; 2622 2623 ret = ftrace_arch_code_modify_prepare(); 2624 FTRACE_WARN_ON(ret); 2625 if (ret) 2626 return; 2627 2628 /* 2629 * By default we use stop_machine() to modify the code. 2630 * But archs can do what ever they want as long as it 2631 * is safe. The stop_machine() is the safest, but also 2632 * produces the most overhead. 2633 */ 2634 arch_ftrace_update_code(command); 2635 2636 ret = ftrace_arch_code_modify_post_process(); 2637 FTRACE_WARN_ON(ret); 2638 } 2639 2640 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command, 2641 struct ftrace_ops_hash *old_hash) 2642 { 2643 ops->flags |= FTRACE_OPS_FL_MODIFYING; 2644 ops->old_hash.filter_hash = old_hash->filter_hash; 2645 ops->old_hash.notrace_hash = old_hash->notrace_hash; 2646 ftrace_run_update_code(command); 2647 ops->old_hash.filter_hash = NULL; 2648 ops->old_hash.notrace_hash = NULL; 2649 ops->flags &= ~FTRACE_OPS_FL_MODIFYING; 2650 } 2651 2652 static ftrace_func_t saved_ftrace_func; 2653 static int ftrace_start_up; 2654 2655 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops) 2656 { 2657 } 2658 2659 static void per_cpu_ops_free(struct ftrace_ops *ops) 2660 { 2661 free_percpu(ops->disabled); 2662 } 2663 2664 static void ftrace_startup_enable(int command) 2665 { 2666 if (saved_ftrace_func != ftrace_trace_function) { 2667 saved_ftrace_func = ftrace_trace_function; 2668 command |= FTRACE_UPDATE_TRACE_FUNC; 2669 } 2670 2671 if (!command || !ftrace_enabled) 2672 return; 2673 2674 ftrace_run_update_code(command); 2675 } 2676 2677 static void ftrace_startup_all(int command) 2678 { 2679 update_all_ops = true; 2680 ftrace_startup_enable(command); 2681 update_all_ops = false; 2682 } 2683 2684 static int ftrace_startup(struct ftrace_ops *ops, int command) 2685 { 2686 int ret; 2687 2688 if (unlikely(ftrace_disabled)) 2689 return -ENODEV; 2690 2691 ret = __register_ftrace_function(ops); 2692 if (ret) 2693 return ret; 2694 2695 ftrace_start_up++; 2696 2697 /* 2698 * Note that ftrace probes uses this to start up 2699 * and modify functions it will probe. But we still 2700 * set the ADDING flag for modification, as probes 2701 * do not have trampolines. If they add them in the 2702 * future, then the probes will need to distinguish 2703 * between adding and updating probes. 2704 */ 2705 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING; 2706 2707 ret = ftrace_hash_ipmodify_enable(ops); 2708 if (ret < 0) { 2709 /* Rollback registration process */ 2710 __unregister_ftrace_function(ops); 2711 ftrace_start_up--; 2712 ops->flags &= ~FTRACE_OPS_FL_ENABLED; 2713 return ret; 2714 } 2715 2716 if (ftrace_hash_rec_enable(ops, 1)) 2717 command |= FTRACE_UPDATE_CALLS; 2718 2719 ftrace_startup_enable(command); 2720 2721 ops->flags &= ~FTRACE_OPS_FL_ADDING; 2722 2723 return 0; 2724 } 2725 2726 static int ftrace_shutdown(struct ftrace_ops *ops, int command) 2727 { 2728 int ret; 2729 2730 if (unlikely(ftrace_disabled)) 2731 return -ENODEV; 2732 2733 ret = __unregister_ftrace_function(ops); 2734 if (ret) 2735 return ret; 2736 2737 ftrace_start_up--; 2738 /* 2739 * Just warn in case of unbalance, no need to kill ftrace, it's not 2740 * critical but the ftrace_call callers may be never nopped again after 2741 * further ftrace uses. 2742 */ 2743 WARN_ON_ONCE(ftrace_start_up < 0); 2744 2745 /* Disabling ipmodify never fails */ 2746 ftrace_hash_ipmodify_disable(ops); 2747 2748 if (ftrace_hash_rec_disable(ops, 1)) 2749 command |= FTRACE_UPDATE_CALLS; 2750 2751 ops->flags &= ~FTRACE_OPS_FL_ENABLED; 2752 2753 if (saved_ftrace_func != ftrace_trace_function) { 2754 saved_ftrace_func = ftrace_trace_function; 2755 command |= FTRACE_UPDATE_TRACE_FUNC; 2756 } 2757 2758 if (!command || !ftrace_enabled) { 2759 /* 2760 * If these are per_cpu ops, they still need their 2761 * per_cpu field freed. Since, function tracing is 2762 * not currently active, we can just free them 2763 * without synchronizing all CPUs. 2764 */ 2765 if (ops->flags & FTRACE_OPS_FL_PER_CPU) 2766 per_cpu_ops_free(ops); 2767 return 0; 2768 } 2769 2770 /* 2771 * If the ops uses a trampoline, then it needs to be 2772 * tested first on update. 2773 */ 2774 ops->flags |= FTRACE_OPS_FL_REMOVING; 2775 removed_ops = ops; 2776 2777 /* The trampoline logic checks the old hashes */ 2778 ops->old_hash.filter_hash = ops->func_hash->filter_hash; 2779 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash; 2780 2781 ftrace_run_update_code(command); 2782 2783 /* 2784 * If there's no more ops registered with ftrace, run a 2785 * sanity check to make sure all rec flags are cleared. 2786 */ 2787 if (ftrace_ops_list == &ftrace_list_end) { 2788 struct ftrace_page *pg; 2789 struct dyn_ftrace *rec; 2790 2791 do_for_each_ftrace_rec(pg, rec) { 2792 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED)) 2793 pr_warn(" %pS flags:%lx\n", 2794 (void *)rec->ip, rec->flags); 2795 } while_for_each_ftrace_rec(); 2796 } 2797 2798 ops->old_hash.filter_hash = NULL; 2799 ops->old_hash.notrace_hash = NULL; 2800 2801 removed_ops = NULL; 2802 ops->flags &= ~FTRACE_OPS_FL_REMOVING; 2803 2804 /* 2805 * Dynamic ops may be freed, we must make sure that all 2806 * callers are done before leaving this function. 2807 * The same goes for freeing the per_cpu data of the per_cpu 2808 * ops. 2809 */ 2810 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) { 2811 /* 2812 * We need to do a hard force of sched synchronization. 2813 * This is because we use preempt_disable() to do RCU, but 2814 * the function tracers can be called where RCU is not watching 2815 * (like before user_exit()). We can not rely on the RCU 2816 * infrastructure to do the synchronization, thus we must do it 2817 * ourselves. 2818 */ 2819 schedule_on_each_cpu(ftrace_sync); 2820 2821 /* 2822 * When the kernel is preeptive, tasks can be preempted 2823 * while on a ftrace trampoline. Just scheduling a task on 2824 * a CPU is not good enough to flush them. Calling 2825 * synchornize_rcu_tasks() will wait for those tasks to 2826 * execute and either schedule voluntarily or enter user space. 2827 */ 2828 if (IS_ENABLED(CONFIG_PREEMPT)) 2829 synchronize_rcu_tasks(); 2830 2831 arch_ftrace_trampoline_free(ops); 2832 2833 if (ops->flags & FTRACE_OPS_FL_PER_CPU) 2834 per_cpu_ops_free(ops); 2835 } 2836 2837 return 0; 2838 } 2839 2840 static void ftrace_startup_sysctl(void) 2841 { 2842 int command; 2843 2844 if (unlikely(ftrace_disabled)) 2845 return; 2846 2847 /* Force update next time */ 2848 saved_ftrace_func = NULL; 2849 /* ftrace_start_up is true if we want ftrace running */ 2850 if (ftrace_start_up) { 2851 command = FTRACE_UPDATE_CALLS; 2852 if (ftrace_graph_active) 2853 command |= FTRACE_START_FUNC_RET; 2854 ftrace_startup_enable(command); 2855 } 2856 } 2857 2858 static void ftrace_shutdown_sysctl(void) 2859 { 2860 int command; 2861 2862 if (unlikely(ftrace_disabled)) 2863 return; 2864 2865 /* ftrace_start_up is true if ftrace is running */ 2866 if (ftrace_start_up) { 2867 command = FTRACE_DISABLE_CALLS; 2868 if (ftrace_graph_active) 2869 command |= FTRACE_STOP_FUNC_RET; 2870 ftrace_run_update_code(command); 2871 } 2872 } 2873 2874 static u64 ftrace_update_time; 2875 unsigned long ftrace_update_tot_cnt; 2876 2877 static inline int ops_traces_mod(struct ftrace_ops *ops) 2878 { 2879 /* 2880 * Filter_hash being empty will default to trace module. 2881 * But notrace hash requires a test of individual module functions. 2882 */ 2883 return ftrace_hash_empty(ops->func_hash->filter_hash) && 2884 ftrace_hash_empty(ops->func_hash->notrace_hash); 2885 } 2886 2887 /* 2888 * Check if the current ops references the record. 2889 * 2890 * If the ops traces all functions, then it was already accounted for. 2891 * If the ops does not trace the current record function, skip it. 2892 * If the ops ignores the function via notrace filter, skip it. 2893 */ 2894 static inline bool 2895 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec) 2896 { 2897 /* If ops isn't enabled, ignore it */ 2898 if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) 2899 return 0; 2900 2901 /* If ops traces all then it includes this function */ 2902 if (ops_traces_mod(ops)) 2903 return 1; 2904 2905 /* The function must be in the filter */ 2906 if (!ftrace_hash_empty(ops->func_hash->filter_hash) && 2907 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip)) 2908 return 0; 2909 2910 /* If in notrace hash, we ignore it too */ 2911 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) 2912 return 0; 2913 2914 return 1; 2915 } 2916 2917 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs) 2918 { 2919 struct ftrace_page *pg; 2920 struct dyn_ftrace *p; 2921 u64 start, stop; 2922 unsigned long update_cnt = 0; 2923 unsigned long rec_flags = 0; 2924 int i; 2925 2926 start = ftrace_now(raw_smp_processor_id()); 2927 2928 /* 2929 * When a module is loaded, this function is called to convert 2930 * the calls to mcount in its text to nops, and also to create 2931 * an entry in the ftrace data. Now, if ftrace is activated 2932 * after this call, but before the module sets its text to 2933 * read-only, the modification of enabling ftrace can fail if 2934 * the read-only is done while ftrace is converting the calls. 2935 * To prevent this, the module's records are set as disabled 2936 * and will be enabled after the call to set the module's text 2937 * to read-only. 2938 */ 2939 if (mod) 2940 rec_flags |= FTRACE_FL_DISABLED; 2941 2942 for (pg = new_pgs; pg; pg = pg->next) { 2943 2944 for (i = 0; i < pg->index; i++) { 2945 2946 /* If something went wrong, bail without enabling anything */ 2947 if (unlikely(ftrace_disabled)) 2948 return -1; 2949 2950 p = &pg->records[i]; 2951 p->flags = rec_flags; 2952 2953 /* 2954 * Do the initial record conversion from mcount jump 2955 * to the NOP instructions. 2956 */ 2957 if (!ftrace_code_disable(mod, p)) 2958 break; 2959 2960 update_cnt++; 2961 } 2962 } 2963 2964 stop = ftrace_now(raw_smp_processor_id()); 2965 ftrace_update_time = stop - start; 2966 ftrace_update_tot_cnt += update_cnt; 2967 2968 return 0; 2969 } 2970 2971 static int ftrace_allocate_records(struct ftrace_page *pg, int count) 2972 { 2973 int order; 2974 int cnt; 2975 2976 if (WARN_ON(!count)) 2977 return -EINVAL; 2978 2979 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE)); 2980 2981 /* 2982 * We want to fill as much as possible. No more than a page 2983 * may be empty. 2984 */ 2985 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE) 2986 order--; 2987 2988 again: 2989 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order); 2990 2991 if (!pg->records) { 2992 /* if we can't allocate this size, try something smaller */ 2993 if (!order) 2994 return -ENOMEM; 2995 order >>= 1; 2996 goto again; 2997 } 2998 2999 cnt = (PAGE_SIZE << order) / ENTRY_SIZE; 3000 pg->size = cnt; 3001 3002 if (cnt > count) 3003 cnt = count; 3004 3005 return cnt; 3006 } 3007 3008 static struct ftrace_page * 3009 ftrace_allocate_pages(unsigned long num_to_init) 3010 { 3011 struct ftrace_page *start_pg; 3012 struct ftrace_page *pg; 3013 int order; 3014 int cnt; 3015 3016 if (!num_to_init) 3017 return 0; 3018 3019 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL); 3020 if (!pg) 3021 return NULL; 3022 3023 /* 3024 * Try to allocate as much as possible in one continues 3025 * location that fills in all of the space. We want to 3026 * waste as little space as possible. 3027 */ 3028 for (;;) { 3029 cnt = ftrace_allocate_records(pg, num_to_init); 3030 if (cnt < 0) 3031 goto free_pages; 3032 3033 num_to_init -= cnt; 3034 if (!num_to_init) 3035 break; 3036 3037 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL); 3038 if (!pg->next) 3039 goto free_pages; 3040 3041 pg = pg->next; 3042 } 3043 3044 return start_pg; 3045 3046 free_pages: 3047 pg = start_pg; 3048 while (pg) { 3049 order = get_count_order(pg->size / ENTRIES_PER_PAGE); 3050 free_pages((unsigned long)pg->records, order); 3051 start_pg = pg->next; 3052 kfree(pg); 3053 pg = start_pg; 3054 } 3055 pr_info("ftrace: FAILED to allocate memory for functions\n"); 3056 return NULL; 3057 } 3058 3059 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ 3060 3061 struct ftrace_iterator { 3062 loff_t pos; 3063 loff_t func_pos; 3064 struct ftrace_page *pg; 3065 struct dyn_ftrace *func; 3066 struct ftrace_func_probe *probe; 3067 struct ftrace_func_entry *probe_entry; 3068 struct trace_parser parser; 3069 struct ftrace_hash *hash; 3070 struct ftrace_ops *ops; 3071 int pidx; 3072 int idx; 3073 unsigned flags; 3074 }; 3075 3076 static void * 3077 t_probe_next(struct seq_file *m, loff_t *pos) 3078 { 3079 struct ftrace_iterator *iter = m->private; 3080 struct trace_array *tr = iter->ops->private; 3081 struct list_head *func_probes; 3082 struct ftrace_hash *hash; 3083 struct list_head *next; 3084 struct hlist_node *hnd = NULL; 3085 struct hlist_head *hhd; 3086 int size; 3087 3088 (*pos)++; 3089 iter->pos = *pos; 3090 3091 if (!tr) 3092 return NULL; 3093 3094 func_probes = &tr->func_probes; 3095 if (list_empty(func_probes)) 3096 return NULL; 3097 3098 if (!iter->probe) { 3099 next = func_probes->next; 3100 iter->probe = list_entry(next, struct ftrace_func_probe, list); 3101 } 3102 3103 if (iter->probe_entry) 3104 hnd = &iter->probe_entry->hlist; 3105 3106 hash = iter->probe->ops.func_hash->filter_hash; 3107 size = 1 << hash->size_bits; 3108 3109 retry: 3110 if (iter->pidx >= size) { 3111 if (iter->probe->list.next == func_probes) 3112 return NULL; 3113 next = iter->probe->list.next; 3114 iter->probe = list_entry(next, struct ftrace_func_probe, list); 3115 hash = iter->probe->ops.func_hash->filter_hash; 3116 size = 1 << hash->size_bits; 3117 iter->pidx = 0; 3118 } 3119 3120 hhd = &hash->buckets[iter->pidx]; 3121 3122 if (hlist_empty(hhd)) { 3123 iter->pidx++; 3124 hnd = NULL; 3125 goto retry; 3126 } 3127 3128 if (!hnd) 3129 hnd = hhd->first; 3130 else { 3131 hnd = hnd->next; 3132 if (!hnd) { 3133 iter->pidx++; 3134 goto retry; 3135 } 3136 } 3137 3138 if (WARN_ON_ONCE(!hnd)) 3139 return NULL; 3140 3141 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist); 3142 3143 return iter; 3144 } 3145 3146 static void *t_probe_start(struct seq_file *m, loff_t *pos) 3147 { 3148 struct ftrace_iterator *iter = m->private; 3149 void *p = NULL; 3150 loff_t l; 3151 3152 if (!(iter->flags & FTRACE_ITER_DO_PROBES)) 3153 return NULL; 3154 3155 if (iter->func_pos > *pos) 3156 return NULL; 3157 3158 iter->probe = NULL; 3159 iter->probe_entry = NULL; 3160 iter->pidx = 0; 3161 for (l = 0; l <= (*pos - iter->func_pos); ) { 3162 p = t_probe_next(m, &l); 3163 if (!p) 3164 break; 3165 } 3166 if (!p) 3167 return NULL; 3168 3169 /* Only set this if we have an item */ 3170 iter->flags |= FTRACE_ITER_PROBE; 3171 3172 return iter; 3173 } 3174 3175 static int 3176 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter) 3177 { 3178 struct ftrace_func_entry *probe_entry; 3179 struct ftrace_probe_ops *probe_ops; 3180 struct ftrace_func_probe *probe; 3181 3182 probe = iter->probe; 3183 probe_entry = iter->probe_entry; 3184 3185 if (WARN_ON_ONCE(!probe || !probe_entry)) 3186 return -EIO; 3187 3188 probe_ops = probe->probe_ops; 3189 3190 if (probe_ops->print) 3191 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data); 3192 3193 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip, 3194 (void *)probe_ops->func); 3195 3196 return 0; 3197 } 3198 3199 static void * 3200 t_func_next(struct seq_file *m, loff_t *pos) 3201 { 3202 struct ftrace_iterator *iter = m->private; 3203 struct dyn_ftrace *rec = NULL; 3204 3205 (*pos)++; 3206 3207 retry: 3208 if (iter->idx >= iter->pg->index) { 3209 if (iter->pg->next) { 3210 iter->pg = iter->pg->next; 3211 iter->idx = 0; 3212 goto retry; 3213 } 3214 } else { 3215 rec = &iter->pg->records[iter->idx++]; 3216 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) && 3217 !ftrace_lookup_ip(iter->hash, rec->ip)) || 3218 3219 ((iter->flags & FTRACE_ITER_ENABLED) && 3220 !(rec->flags & FTRACE_FL_ENABLED))) { 3221 3222 rec = NULL; 3223 goto retry; 3224 } 3225 } 3226 3227 if (!rec) 3228 return NULL; 3229 3230 iter->pos = iter->func_pos = *pos; 3231 iter->func = rec; 3232 3233 return iter; 3234 } 3235 3236 static void * 3237 t_next(struct seq_file *m, void *v, loff_t *pos) 3238 { 3239 struct ftrace_iterator *iter = m->private; 3240 loff_t l = *pos; /* t_hash_start() must use original pos */ 3241 void *ret; 3242 3243 if (unlikely(ftrace_disabled)) 3244 return NULL; 3245 3246 if (iter->flags & FTRACE_ITER_PROBE) 3247 return t_probe_next(m, pos); 3248 3249 if (iter->flags & FTRACE_ITER_PRINTALL) { 3250 /* next must increment pos, and t_probe_start does not */ 3251 (*pos)++; 3252 return t_probe_start(m, &l); 3253 } 3254 3255 ret = t_func_next(m, pos); 3256 3257 if (!ret) 3258 return t_probe_start(m, &l); 3259 3260 return ret; 3261 } 3262 3263 static void reset_iter_read(struct ftrace_iterator *iter) 3264 { 3265 iter->pos = 0; 3266 iter->func_pos = 0; 3267 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE); 3268 } 3269 3270 static void *t_start(struct seq_file *m, loff_t *pos) 3271 { 3272 struct ftrace_iterator *iter = m->private; 3273 void *p = NULL; 3274 loff_t l; 3275 3276 mutex_lock(&ftrace_lock); 3277 3278 if (unlikely(ftrace_disabled)) 3279 return NULL; 3280 3281 /* 3282 * If an lseek was done, then reset and start from beginning. 3283 */ 3284 if (*pos < iter->pos) 3285 reset_iter_read(iter); 3286 3287 /* 3288 * For set_ftrace_filter reading, if we have the filter 3289 * off, we can short cut and just print out that all 3290 * functions are enabled. 3291 */ 3292 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) && 3293 ftrace_hash_empty(iter->hash)) { 3294 iter->func_pos = 1; /* Account for the message */ 3295 if (*pos > 0) 3296 return t_probe_start(m, pos); 3297 iter->flags |= FTRACE_ITER_PRINTALL; 3298 /* reset in case of seek/pread */ 3299 iter->flags &= ~FTRACE_ITER_PROBE; 3300 return iter; 3301 } 3302 3303 if (iter->flags & FTRACE_ITER_PROBE) 3304 return t_probe_start(m, pos); 3305 3306 /* 3307 * Unfortunately, we need to restart at ftrace_pages_start 3308 * every time we let go of the ftrace_mutex. This is because 3309 * those pointers can change without the lock. 3310 */ 3311 iter->pg = ftrace_pages_start; 3312 iter->idx = 0; 3313 for (l = 0; l <= *pos; ) { 3314 p = t_func_next(m, &l); 3315 if (!p) 3316 break; 3317 } 3318 3319 if (!p) 3320 return t_probe_start(m, pos); 3321 3322 return iter; 3323 } 3324 3325 static void t_stop(struct seq_file *m, void *p) 3326 { 3327 mutex_unlock(&ftrace_lock); 3328 } 3329 3330 void * __weak 3331 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec) 3332 { 3333 return NULL; 3334 } 3335 3336 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops, 3337 struct dyn_ftrace *rec) 3338 { 3339 void *ptr; 3340 3341 ptr = arch_ftrace_trampoline_func(ops, rec); 3342 if (ptr) 3343 seq_printf(m, " ->%pS", ptr); 3344 } 3345 3346 static int t_show(struct seq_file *m, void *v) 3347 { 3348 struct ftrace_iterator *iter = m->private; 3349 struct dyn_ftrace *rec; 3350 3351 if (iter->flags & FTRACE_ITER_PROBE) 3352 return t_probe_show(m, iter); 3353 3354 if (iter->flags & FTRACE_ITER_PRINTALL) { 3355 if (iter->flags & FTRACE_ITER_NOTRACE) 3356 seq_puts(m, "#### no functions disabled ####\n"); 3357 else 3358 seq_puts(m, "#### all functions enabled ####\n"); 3359 return 0; 3360 } 3361 3362 rec = iter->func; 3363 3364 if (!rec) 3365 return 0; 3366 3367 seq_printf(m, "%ps", (void *)rec->ip); 3368 if (iter->flags & FTRACE_ITER_ENABLED) { 3369 struct ftrace_ops *ops; 3370 3371 seq_printf(m, " (%ld)%s%s", 3372 ftrace_rec_count(rec), 3373 rec->flags & FTRACE_FL_REGS ? " R" : " ", 3374 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " "); 3375 if (rec->flags & FTRACE_FL_TRAMP_EN) { 3376 ops = ftrace_find_tramp_ops_any(rec); 3377 if (ops) { 3378 do { 3379 seq_printf(m, "\ttramp: %pS (%pS)", 3380 (void *)ops->trampoline, 3381 (void *)ops->func); 3382 add_trampoline_func(m, ops, rec); 3383 ops = ftrace_find_tramp_ops_next(rec, ops); 3384 } while (ops); 3385 } else 3386 seq_puts(m, "\ttramp: ERROR!"); 3387 } else { 3388 add_trampoline_func(m, NULL, rec); 3389 } 3390 } 3391 3392 seq_putc(m, '\n'); 3393 3394 return 0; 3395 } 3396 3397 static const struct seq_operations show_ftrace_seq_ops = { 3398 .start = t_start, 3399 .next = t_next, 3400 .stop = t_stop, 3401 .show = t_show, 3402 }; 3403 3404 static int 3405 ftrace_avail_open(struct inode *inode, struct file *file) 3406 { 3407 struct ftrace_iterator *iter; 3408 3409 if (unlikely(ftrace_disabled)) 3410 return -ENODEV; 3411 3412 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); 3413 if (!iter) 3414 return -ENOMEM; 3415 3416 iter->pg = ftrace_pages_start; 3417 iter->ops = &global_ops; 3418 3419 return 0; 3420 } 3421 3422 static int 3423 ftrace_enabled_open(struct inode *inode, struct file *file) 3424 { 3425 struct ftrace_iterator *iter; 3426 3427 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); 3428 if (!iter) 3429 return -ENOMEM; 3430 3431 iter->pg = ftrace_pages_start; 3432 iter->flags = FTRACE_ITER_ENABLED; 3433 iter->ops = &global_ops; 3434 3435 return 0; 3436 } 3437 3438 /** 3439 * ftrace_regex_open - initialize function tracer filter files 3440 * @ops: The ftrace_ops that hold the hash filters 3441 * @flag: The type of filter to process 3442 * @inode: The inode, usually passed in to your open routine 3443 * @file: The file, usually passed in to your open routine 3444 * 3445 * ftrace_regex_open() initializes the filter files for the 3446 * @ops. Depending on @flag it may process the filter hash or 3447 * the notrace hash of @ops. With this called from the open 3448 * routine, you can use ftrace_filter_write() for the write 3449 * routine if @flag has FTRACE_ITER_FILTER set, or 3450 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set. 3451 * tracing_lseek() should be used as the lseek routine, and 3452 * release must call ftrace_regex_release(). 3453 */ 3454 int 3455 ftrace_regex_open(struct ftrace_ops *ops, int flag, 3456 struct inode *inode, struct file *file) 3457 { 3458 struct ftrace_iterator *iter; 3459 struct ftrace_hash *hash; 3460 int ret = 0; 3461 3462 ftrace_ops_init(ops); 3463 3464 if (unlikely(ftrace_disabled)) 3465 return -ENODEV; 3466 3467 iter = kzalloc(sizeof(*iter), GFP_KERNEL); 3468 if (!iter) 3469 return -ENOMEM; 3470 3471 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) { 3472 kfree(iter); 3473 return -ENOMEM; 3474 } 3475 3476 iter->ops = ops; 3477 iter->flags = flag; 3478 3479 mutex_lock(&ops->func_hash->regex_lock); 3480 3481 if (flag & FTRACE_ITER_NOTRACE) 3482 hash = ops->func_hash->notrace_hash; 3483 else 3484 hash = ops->func_hash->filter_hash; 3485 3486 if (file->f_mode & FMODE_WRITE) { 3487 const int size_bits = FTRACE_HASH_DEFAULT_BITS; 3488 3489 if (file->f_flags & O_TRUNC) 3490 iter->hash = alloc_ftrace_hash(size_bits); 3491 else 3492 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash); 3493 3494 if (!iter->hash) { 3495 trace_parser_put(&iter->parser); 3496 kfree(iter); 3497 ret = -ENOMEM; 3498 goto out_unlock; 3499 } 3500 } else 3501 iter->hash = hash; 3502 3503 if (file->f_mode & FMODE_READ) { 3504 iter->pg = ftrace_pages_start; 3505 3506 ret = seq_open(file, &show_ftrace_seq_ops); 3507 if (!ret) { 3508 struct seq_file *m = file->private_data; 3509 m->private = iter; 3510 } else { 3511 /* Failed */ 3512 free_ftrace_hash(iter->hash); 3513 trace_parser_put(&iter->parser); 3514 kfree(iter); 3515 } 3516 } else 3517 file->private_data = iter; 3518 3519 out_unlock: 3520 mutex_unlock(&ops->func_hash->regex_lock); 3521 3522 return ret; 3523 } 3524 3525 static int 3526 ftrace_filter_open(struct inode *inode, struct file *file) 3527 { 3528 struct ftrace_ops *ops = inode->i_private; 3529 3530 return ftrace_regex_open(ops, 3531 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES, 3532 inode, file); 3533 } 3534 3535 static int 3536 ftrace_notrace_open(struct inode *inode, struct file *file) 3537 { 3538 struct ftrace_ops *ops = inode->i_private; 3539 3540 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE, 3541 inode, file); 3542 } 3543 3544 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */ 3545 struct ftrace_glob { 3546 char *search; 3547 unsigned len; 3548 int type; 3549 }; 3550 3551 /* 3552 * If symbols in an architecture don't correspond exactly to the user-visible 3553 * name of what they represent, it is possible to define this function to 3554 * perform the necessary adjustments. 3555 */ 3556 char * __weak arch_ftrace_match_adjust(char *str, const char *search) 3557 { 3558 return str; 3559 } 3560 3561 static int ftrace_match(char *str, struct ftrace_glob *g) 3562 { 3563 int matched = 0; 3564 int slen; 3565 3566 str = arch_ftrace_match_adjust(str, g->search); 3567 3568 switch (g->type) { 3569 case MATCH_FULL: 3570 if (strcmp(str, g->search) == 0) 3571 matched = 1; 3572 break; 3573 case MATCH_FRONT_ONLY: 3574 if (strncmp(str, g->search, g->len) == 0) 3575 matched = 1; 3576 break; 3577 case MATCH_MIDDLE_ONLY: 3578 if (strstr(str, g->search)) 3579 matched = 1; 3580 break; 3581 case MATCH_END_ONLY: 3582 slen = strlen(str); 3583 if (slen >= g->len && 3584 memcmp(str + slen - g->len, g->search, g->len) == 0) 3585 matched = 1; 3586 break; 3587 case MATCH_GLOB: 3588 if (glob_match(g->search, str)) 3589 matched = 1; 3590 break; 3591 } 3592 3593 return matched; 3594 } 3595 3596 static int 3597 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter) 3598 { 3599 struct ftrace_func_entry *entry; 3600 int ret = 0; 3601 3602 entry = ftrace_lookup_ip(hash, rec->ip); 3603 if (clear_filter) { 3604 /* Do nothing if it doesn't exist */ 3605 if (!entry) 3606 return 0; 3607 3608 free_hash_entry(hash, entry); 3609 } else { 3610 /* Do nothing if it exists */ 3611 if (entry) 3612 return 0; 3613 3614 ret = add_hash_entry(hash, rec->ip); 3615 } 3616 return ret; 3617 } 3618 3619 static int 3620 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g, 3621 struct ftrace_glob *mod_g, int exclude_mod) 3622 { 3623 char str[KSYM_SYMBOL_LEN]; 3624 char *modname; 3625 3626 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); 3627 3628 if (mod_g) { 3629 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0; 3630 3631 /* blank module name to match all modules */ 3632 if (!mod_g->len) { 3633 /* blank module globbing: modname xor exclude_mod */ 3634 if (!exclude_mod != !modname) 3635 goto func_match; 3636 return 0; 3637 } 3638 3639 /* 3640 * exclude_mod is set to trace everything but the given 3641 * module. If it is set and the module matches, then 3642 * return 0. If it is not set, and the module doesn't match 3643 * also return 0. Otherwise, check the function to see if 3644 * that matches. 3645 */ 3646 if (!mod_matches == !exclude_mod) 3647 return 0; 3648 func_match: 3649 /* blank search means to match all funcs in the mod */ 3650 if (!func_g->len) 3651 return 1; 3652 } 3653 3654 return ftrace_match(str, func_g); 3655 } 3656 3657 static int 3658 match_records(struct ftrace_hash *hash, char *func, int len, char *mod) 3659 { 3660 struct ftrace_page *pg; 3661 struct dyn_ftrace *rec; 3662 struct ftrace_glob func_g = { .type = MATCH_FULL }; 3663 struct ftrace_glob mod_g = { .type = MATCH_FULL }; 3664 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL; 3665 int exclude_mod = 0; 3666 int found = 0; 3667 int ret; 3668 int clear_filter; 3669 3670 if (func) { 3671 func_g.type = filter_parse_regex(func, len, &func_g.search, 3672 &clear_filter); 3673 func_g.len = strlen(func_g.search); 3674 } 3675 3676 if (mod) { 3677 mod_g.type = filter_parse_regex(mod, strlen(mod), 3678 &mod_g.search, &exclude_mod); 3679 mod_g.len = strlen(mod_g.search); 3680 } 3681 3682 mutex_lock(&ftrace_lock); 3683 3684 if (unlikely(ftrace_disabled)) 3685 goto out_unlock; 3686 3687 do_for_each_ftrace_rec(pg, rec) { 3688 3689 if (rec->flags & FTRACE_FL_DISABLED) 3690 continue; 3691 3692 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) { 3693 ret = enter_record(hash, rec, clear_filter); 3694 if (ret < 0) { 3695 found = ret; 3696 goto out_unlock; 3697 } 3698 found = 1; 3699 } 3700 } while_for_each_ftrace_rec(); 3701 out_unlock: 3702 mutex_unlock(&ftrace_lock); 3703 3704 return found; 3705 } 3706 3707 static int 3708 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len) 3709 { 3710 return match_records(hash, buff, len, NULL); 3711 } 3712 3713 static void ftrace_ops_update_code(struct ftrace_ops *ops, 3714 struct ftrace_ops_hash *old_hash) 3715 { 3716 struct ftrace_ops *op; 3717 3718 if (!ftrace_enabled) 3719 return; 3720 3721 if (ops->flags & FTRACE_OPS_FL_ENABLED) { 3722 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash); 3723 return; 3724 } 3725 3726 /* 3727 * If this is the shared global_ops filter, then we need to 3728 * check if there is another ops that shares it, is enabled. 3729 * If so, we still need to run the modify code. 3730 */ 3731 if (ops->func_hash != &global_ops.local_hash) 3732 return; 3733 3734 do_for_each_ftrace_op(op, ftrace_ops_list) { 3735 if (op->func_hash == &global_ops.local_hash && 3736 op->flags & FTRACE_OPS_FL_ENABLED) { 3737 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash); 3738 /* Only need to do this once */ 3739 return; 3740 } 3741 } while_for_each_ftrace_op(op); 3742 } 3743 3744 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops, 3745 struct ftrace_hash **orig_hash, 3746 struct ftrace_hash *hash, 3747 int enable) 3748 { 3749 struct ftrace_ops_hash old_hash_ops; 3750 struct ftrace_hash *old_hash; 3751 int ret; 3752 3753 old_hash = *orig_hash; 3754 old_hash_ops.filter_hash = ops->func_hash->filter_hash; 3755 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash; 3756 ret = ftrace_hash_move(ops, enable, orig_hash, hash); 3757 if (!ret) { 3758 ftrace_ops_update_code(ops, &old_hash_ops); 3759 free_ftrace_hash_rcu(old_hash); 3760 } 3761 return ret; 3762 } 3763 3764 /* 3765 * We register the module command as a template to show others how 3766 * to register the a command as well. 3767 */ 3768 3769 static int 3770 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash, 3771 char *func, char *cmd, char *module, int enable) 3772 { 3773 int ret; 3774 3775 /* 3776 * cmd == 'mod' because we only registered this func 3777 * for the 'mod' ftrace_func_command. 3778 * But if you register one func with multiple commands, 3779 * you can tell which command was used by the cmd 3780 * parameter. 3781 */ 3782 ret = match_records(hash, func, strlen(func), module); 3783 if (!ret) 3784 return -EINVAL; 3785 if (ret < 0) 3786 return ret; 3787 return 0; 3788 } 3789 3790 static struct ftrace_func_command ftrace_mod_cmd = { 3791 .name = "mod", 3792 .func = ftrace_mod_callback, 3793 }; 3794 3795 static int __init ftrace_mod_cmd_init(void) 3796 { 3797 return register_ftrace_command(&ftrace_mod_cmd); 3798 } 3799 core_initcall(ftrace_mod_cmd_init); 3800 3801 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip, 3802 struct ftrace_ops *op, struct pt_regs *pt_regs) 3803 { 3804 struct ftrace_probe_ops *probe_ops; 3805 struct ftrace_func_probe *probe; 3806 3807 probe = container_of(op, struct ftrace_func_probe, ops); 3808 probe_ops = probe->probe_ops; 3809 3810 /* 3811 * Disable preemption for these calls to prevent a RCU grace 3812 * period. This syncs the hash iteration and freeing of items 3813 * on the hash. rcu_read_lock is too dangerous here. 3814 */ 3815 preempt_disable_notrace(); 3816 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data); 3817 preempt_enable_notrace(); 3818 } 3819 3820 struct ftrace_func_map { 3821 struct ftrace_func_entry entry; 3822 void *data; 3823 }; 3824 3825 struct ftrace_func_mapper { 3826 struct ftrace_hash hash; 3827 }; 3828 3829 /** 3830 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper 3831 * 3832 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data. 3833 */ 3834 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void) 3835 { 3836 struct ftrace_hash *hash; 3837 3838 /* 3839 * The mapper is simply a ftrace_hash, but since the entries 3840 * in the hash are not ftrace_func_entry type, we define it 3841 * as a separate structure. 3842 */ 3843 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); 3844 return (struct ftrace_func_mapper *)hash; 3845 } 3846 3847 /** 3848 * ftrace_func_mapper_find_ip - Find some data mapped to an ip 3849 * @mapper: The mapper that has the ip maps 3850 * @ip: the instruction pointer to find the data for 3851 * 3852 * Returns the data mapped to @ip if found otherwise NULL. The return 3853 * is actually the address of the mapper data pointer. The address is 3854 * returned for use cases where the data is no bigger than a long, and 3855 * the user can use the data pointer as its data instead of having to 3856 * allocate more memory for the reference. 3857 */ 3858 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper, 3859 unsigned long ip) 3860 { 3861 struct ftrace_func_entry *entry; 3862 struct ftrace_func_map *map; 3863 3864 entry = ftrace_lookup_ip(&mapper->hash, ip); 3865 if (!entry) 3866 return NULL; 3867 3868 map = (struct ftrace_func_map *)entry; 3869 return &map->data; 3870 } 3871 3872 /** 3873 * ftrace_func_mapper_add_ip - Map some data to an ip 3874 * @mapper: The mapper that has the ip maps 3875 * @ip: The instruction pointer address to map @data to 3876 * @data: The data to map to @ip 3877 * 3878 * Returns 0 on succes otherwise an error. 3879 */ 3880 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper, 3881 unsigned long ip, void *data) 3882 { 3883 struct ftrace_func_entry *entry; 3884 struct ftrace_func_map *map; 3885 3886 entry = ftrace_lookup_ip(&mapper->hash, ip); 3887 if (entry) 3888 return -EBUSY; 3889 3890 map = kmalloc(sizeof(*map), GFP_KERNEL); 3891 if (!map) 3892 return -ENOMEM; 3893 3894 map->entry.ip = ip; 3895 map->data = data; 3896 3897 __add_hash_entry(&mapper->hash, &map->entry); 3898 3899 return 0; 3900 } 3901 3902 /** 3903 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping 3904 * @mapper: The mapper that has the ip maps 3905 * @ip: The instruction pointer address to remove the data from 3906 * 3907 * Returns the data if it is found, otherwise NULL. 3908 * Note, if the data pointer is used as the data itself, (see 3909 * ftrace_func_mapper_find_ip(), then the return value may be meaningless, 3910 * if the data pointer was set to zero. 3911 */ 3912 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper, 3913 unsigned long ip) 3914 { 3915 struct ftrace_func_entry *entry; 3916 struct ftrace_func_map *map; 3917 void *data; 3918 3919 entry = ftrace_lookup_ip(&mapper->hash, ip); 3920 if (!entry) 3921 return NULL; 3922 3923 map = (struct ftrace_func_map *)entry; 3924 data = map->data; 3925 3926 remove_hash_entry(&mapper->hash, entry); 3927 kfree(entry); 3928 3929 return data; 3930 } 3931 3932 /** 3933 * free_ftrace_func_mapper - free a mapping of ips and data 3934 * @mapper: The mapper that has the ip maps 3935 * @free_func: A function to be called on each data item. 3936 * 3937 * This is used to free the function mapper. The @free_func is optional 3938 * and can be used if the data needs to be freed as well. 3939 */ 3940 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper, 3941 ftrace_mapper_func free_func) 3942 { 3943 struct ftrace_func_entry *entry; 3944 struct ftrace_func_map *map; 3945 struct hlist_head *hhd; 3946 int size = 1 << mapper->hash.size_bits; 3947 int i; 3948 3949 if (free_func && mapper->hash.count) { 3950 for (i = 0; i < size; i++) { 3951 hhd = &mapper->hash.buckets[i]; 3952 hlist_for_each_entry(entry, hhd, hlist) { 3953 map = (struct ftrace_func_map *)entry; 3954 free_func(map); 3955 } 3956 } 3957 } 3958 free_ftrace_hash(&mapper->hash); 3959 } 3960 3961 static void release_probe(struct ftrace_func_probe *probe) 3962 { 3963 struct ftrace_probe_ops *probe_ops; 3964 3965 mutex_lock(&ftrace_lock); 3966 3967 WARN_ON(probe->ref <= 0); 3968 3969 /* Subtract the ref that was used to protect this instance */ 3970 probe->ref--; 3971 3972 if (!probe->ref) { 3973 probe_ops = probe->probe_ops; 3974 /* 3975 * Sending zero as ip tells probe_ops to free 3976 * the probe->data itself 3977 */ 3978 if (probe_ops->free) 3979 probe_ops->free(probe_ops, probe->tr, 0, probe->data); 3980 list_del(&probe->list); 3981 kfree(probe); 3982 } 3983 mutex_unlock(&ftrace_lock); 3984 } 3985 3986 static void acquire_probe_locked(struct ftrace_func_probe *probe) 3987 { 3988 /* 3989 * Add one ref to keep it from being freed when releasing the 3990 * ftrace_lock mutex. 3991 */ 3992 probe->ref++; 3993 } 3994 3995 int 3996 register_ftrace_function_probe(char *glob, struct trace_array *tr, 3997 struct ftrace_probe_ops *probe_ops, 3998 void *data) 3999 { 4000 struct ftrace_func_entry *entry; 4001 struct ftrace_func_probe *probe; 4002 struct ftrace_hash **orig_hash; 4003 struct ftrace_hash *old_hash; 4004 struct ftrace_hash *hash; 4005 int count = 0; 4006 int size; 4007 int ret; 4008 int i; 4009 4010 if (WARN_ON(!tr)) 4011 return -EINVAL; 4012 4013 /* We do not support '!' for function probes */ 4014 if (WARN_ON(glob[0] == '!')) 4015 return -EINVAL; 4016 4017 4018 mutex_lock(&ftrace_lock); 4019 /* Check if the probe_ops is already registered */ 4020 list_for_each_entry(probe, &tr->func_probes, list) { 4021 if (probe->probe_ops == probe_ops) 4022 break; 4023 } 4024 if (&probe->list == &tr->func_probes) { 4025 probe = kzalloc(sizeof(*probe), GFP_KERNEL); 4026 if (!probe) { 4027 mutex_unlock(&ftrace_lock); 4028 return -ENOMEM; 4029 } 4030 probe->probe_ops = probe_ops; 4031 probe->ops.func = function_trace_probe_call; 4032 probe->tr = tr; 4033 ftrace_ops_init(&probe->ops); 4034 list_add(&probe->list, &tr->func_probes); 4035 } 4036 4037 acquire_probe_locked(probe); 4038 4039 mutex_unlock(&ftrace_lock); 4040 4041 mutex_lock(&probe->ops.func_hash->regex_lock); 4042 4043 orig_hash = &probe->ops.func_hash->filter_hash; 4044 old_hash = *orig_hash; 4045 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash); 4046 4047 ret = ftrace_match_records(hash, glob, strlen(glob)); 4048 4049 /* Nothing found? */ 4050 if (!ret) 4051 ret = -EINVAL; 4052 4053 if (ret < 0) 4054 goto out; 4055 4056 size = 1 << hash->size_bits; 4057 for (i = 0; i < size; i++) { 4058 hlist_for_each_entry(entry, &hash->buckets[i], hlist) { 4059 if (ftrace_lookup_ip(old_hash, entry->ip)) 4060 continue; 4061 /* 4062 * The caller might want to do something special 4063 * for each function we find. We call the callback 4064 * to give the caller an opportunity to do so. 4065 */ 4066 if (probe_ops->init) { 4067 ret = probe_ops->init(probe_ops, tr, 4068 entry->ip, data, 4069 &probe->data); 4070 if (ret < 0) { 4071 if (probe_ops->free && count) 4072 probe_ops->free(probe_ops, tr, 4073 0, probe->data); 4074 probe->data = NULL; 4075 goto out; 4076 } 4077 } 4078 count++; 4079 } 4080 } 4081 4082 mutex_lock(&ftrace_lock); 4083 4084 if (!count) { 4085 /* Nothing was added? */ 4086 ret = -EINVAL; 4087 goto out_unlock; 4088 } 4089 4090 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash, 4091 hash, 1); 4092 if (ret < 0) 4093 goto err_unlock; 4094 4095 /* One ref for each new function traced */ 4096 probe->ref += count; 4097 4098 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED)) 4099 ret = ftrace_startup(&probe->ops, 0); 4100 4101 out_unlock: 4102 mutex_unlock(&ftrace_lock); 4103 4104 if (!ret) 4105 ret = count; 4106 out: 4107 mutex_unlock(&probe->ops.func_hash->regex_lock); 4108 free_ftrace_hash(hash); 4109 4110 release_probe(probe); 4111 4112 return ret; 4113 4114 err_unlock: 4115 if (!probe_ops->free || !count) 4116 goto out_unlock; 4117 4118 /* Failed to do the move, need to call the free functions */ 4119 for (i = 0; i < size; i++) { 4120 hlist_for_each_entry(entry, &hash->buckets[i], hlist) { 4121 if (ftrace_lookup_ip(old_hash, entry->ip)) 4122 continue; 4123 probe_ops->free(probe_ops, tr, entry->ip, probe->data); 4124 } 4125 } 4126 goto out_unlock; 4127 } 4128 4129 int 4130 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr, 4131 struct ftrace_probe_ops *probe_ops) 4132 { 4133 struct ftrace_ops_hash old_hash_ops; 4134 struct ftrace_func_entry *entry; 4135 struct ftrace_func_probe *probe; 4136 struct ftrace_glob func_g; 4137 struct ftrace_hash **orig_hash; 4138 struct ftrace_hash *old_hash; 4139 struct ftrace_hash *hash = NULL; 4140 struct hlist_node *tmp; 4141 struct hlist_head hhd; 4142 char str[KSYM_SYMBOL_LEN]; 4143 int count = 0; 4144 int i, ret = -ENODEV; 4145 int size; 4146 4147 if (!glob || !strlen(glob) || !strcmp(glob, "*")) 4148 func_g.search = NULL; 4149 else { 4150 int not; 4151 4152 func_g.type = filter_parse_regex(glob, strlen(glob), 4153 &func_g.search, ¬); 4154 func_g.len = strlen(func_g.search); 4155 func_g.search = glob; 4156 4157 /* we do not support '!' for function probes */ 4158 if (WARN_ON(not)) 4159 return -EINVAL; 4160 } 4161 4162 mutex_lock(&ftrace_lock); 4163 /* Check if the probe_ops is already registered */ 4164 list_for_each_entry(probe, &tr->func_probes, list) { 4165 if (probe->probe_ops == probe_ops) 4166 break; 4167 } 4168 if (&probe->list == &tr->func_probes) 4169 goto err_unlock_ftrace; 4170 4171 ret = -EINVAL; 4172 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED)) 4173 goto err_unlock_ftrace; 4174 4175 acquire_probe_locked(probe); 4176 4177 mutex_unlock(&ftrace_lock); 4178 4179 mutex_lock(&probe->ops.func_hash->regex_lock); 4180 4181 orig_hash = &probe->ops.func_hash->filter_hash; 4182 old_hash = *orig_hash; 4183 4184 if (ftrace_hash_empty(old_hash)) 4185 goto out_unlock; 4186 4187 old_hash_ops.filter_hash = old_hash; 4188 /* Probes only have filters */ 4189 old_hash_ops.notrace_hash = NULL; 4190 4191 ret = -ENOMEM; 4192 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash); 4193 if (!hash) 4194 goto out_unlock; 4195 4196 INIT_HLIST_HEAD(&hhd); 4197 4198 size = 1 << hash->size_bits; 4199 for (i = 0; i < size; i++) { 4200 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) { 4201 4202 if (func_g.search) { 4203 kallsyms_lookup(entry->ip, NULL, NULL, 4204 NULL, str); 4205 if (!ftrace_match(str, &func_g)) 4206 continue; 4207 } 4208 count++; 4209 remove_hash_entry(hash, entry); 4210 hlist_add_head(&entry->hlist, &hhd); 4211 } 4212 } 4213 4214 /* Nothing found? */ 4215 if (!count) { 4216 ret = -EINVAL; 4217 goto out_unlock; 4218 } 4219 4220 mutex_lock(&ftrace_lock); 4221 4222 WARN_ON(probe->ref < count); 4223 4224 probe->ref -= count; 4225 4226 if (ftrace_hash_empty(hash)) 4227 ftrace_shutdown(&probe->ops, 0); 4228 4229 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash, 4230 hash, 1); 4231 4232 /* still need to update the function call sites */ 4233 if (ftrace_enabled && !ftrace_hash_empty(hash)) 4234 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS, 4235 &old_hash_ops); 4236 synchronize_sched(); 4237 4238 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) { 4239 hlist_del(&entry->hlist); 4240 if (probe_ops->free) 4241 probe_ops->free(probe_ops, tr, entry->ip, probe->data); 4242 kfree(entry); 4243 } 4244 mutex_unlock(&ftrace_lock); 4245 4246 out_unlock: 4247 mutex_unlock(&probe->ops.func_hash->regex_lock); 4248 free_ftrace_hash(hash); 4249 4250 release_probe(probe); 4251 4252 return ret; 4253 4254 err_unlock_ftrace: 4255 mutex_unlock(&ftrace_lock); 4256 return ret; 4257 } 4258 4259 void clear_ftrace_function_probes(struct trace_array *tr) 4260 { 4261 struct ftrace_func_probe *probe, *n; 4262 4263 list_for_each_entry_safe(probe, n, &tr->func_probes, list) 4264 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops); 4265 } 4266 4267 static LIST_HEAD(ftrace_commands); 4268 static DEFINE_MUTEX(ftrace_cmd_mutex); 4269 4270 /* 4271 * Currently we only register ftrace commands from __init, so mark this 4272 * __init too. 4273 */ 4274 __init int register_ftrace_command(struct ftrace_func_command *cmd) 4275 { 4276 struct ftrace_func_command *p; 4277 int ret = 0; 4278 4279 mutex_lock(&ftrace_cmd_mutex); 4280 list_for_each_entry(p, &ftrace_commands, list) { 4281 if (strcmp(cmd->name, p->name) == 0) { 4282 ret = -EBUSY; 4283 goto out_unlock; 4284 } 4285 } 4286 list_add(&cmd->list, &ftrace_commands); 4287 out_unlock: 4288 mutex_unlock(&ftrace_cmd_mutex); 4289 4290 return ret; 4291 } 4292 4293 /* 4294 * Currently we only unregister ftrace commands from __init, so mark 4295 * this __init too. 4296 */ 4297 __init int unregister_ftrace_command(struct ftrace_func_command *cmd) 4298 { 4299 struct ftrace_func_command *p, *n; 4300 int ret = -ENODEV; 4301 4302 mutex_lock(&ftrace_cmd_mutex); 4303 list_for_each_entry_safe(p, n, &ftrace_commands, list) { 4304 if (strcmp(cmd->name, p->name) == 0) { 4305 ret = 0; 4306 list_del_init(&p->list); 4307 goto out_unlock; 4308 } 4309 } 4310 out_unlock: 4311 mutex_unlock(&ftrace_cmd_mutex); 4312 4313 return ret; 4314 } 4315 4316 static int ftrace_process_regex(struct ftrace_iterator *iter, 4317 char *buff, int len, int enable) 4318 { 4319 struct ftrace_hash *hash = iter->hash; 4320 struct trace_array *tr = iter->ops->private; 4321 char *func, *command, *next = buff; 4322 struct ftrace_func_command *p; 4323 int ret = -EINVAL; 4324 4325 func = strsep(&next, ":"); 4326 4327 if (!next) { 4328 ret = ftrace_match_records(hash, func, len); 4329 if (!ret) 4330 ret = -EINVAL; 4331 if (ret < 0) 4332 return ret; 4333 return 0; 4334 } 4335 4336 /* command found */ 4337 4338 command = strsep(&next, ":"); 4339 4340 if (WARN_ON_ONCE(!tr)) 4341 return -EINVAL; 4342 4343 mutex_lock(&ftrace_cmd_mutex); 4344 list_for_each_entry(p, &ftrace_commands, list) { 4345 if (strcmp(p->name, command) == 0) { 4346 ret = p->func(tr, hash, func, command, next, enable); 4347 goto out_unlock; 4348 } 4349 } 4350 out_unlock: 4351 mutex_unlock(&ftrace_cmd_mutex); 4352 4353 return ret; 4354 } 4355 4356 static ssize_t 4357 ftrace_regex_write(struct file *file, const char __user *ubuf, 4358 size_t cnt, loff_t *ppos, int enable) 4359 { 4360 struct ftrace_iterator *iter; 4361 struct trace_parser *parser; 4362 ssize_t ret, read; 4363 4364 if (!cnt) 4365 return 0; 4366 4367 if (file->f_mode & FMODE_READ) { 4368 struct seq_file *m = file->private_data; 4369 iter = m->private; 4370 } else 4371 iter = file->private_data; 4372 4373 if (unlikely(ftrace_disabled)) 4374 return -ENODEV; 4375 4376 /* iter->hash is a local copy, so we don't need regex_lock */ 4377 4378 parser = &iter->parser; 4379 read = trace_get_user(parser, ubuf, cnt, ppos); 4380 4381 if (read >= 0 && trace_parser_loaded(parser) && 4382 !trace_parser_cont(parser)) { 4383 ret = ftrace_process_regex(iter, parser->buffer, 4384 parser->idx, enable); 4385 trace_parser_clear(parser); 4386 if (ret < 0) 4387 goto out; 4388 } 4389 4390 ret = read; 4391 out: 4392 return ret; 4393 } 4394 4395 ssize_t 4396 ftrace_filter_write(struct file *file, const char __user *ubuf, 4397 size_t cnt, loff_t *ppos) 4398 { 4399 return ftrace_regex_write(file, ubuf, cnt, ppos, 1); 4400 } 4401 4402 ssize_t 4403 ftrace_notrace_write(struct file *file, const char __user *ubuf, 4404 size_t cnt, loff_t *ppos) 4405 { 4406 return ftrace_regex_write(file, ubuf, cnt, ppos, 0); 4407 } 4408 4409 static int 4410 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove) 4411 { 4412 struct ftrace_func_entry *entry; 4413 4414 if (!ftrace_location(ip)) 4415 return -EINVAL; 4416 4417 if (remove) { 4418 entry = ftrace_lookup_ip(hash, ip); 4419 if (!entry) 4420 return -ENOENT; 4421 free_hash_entry(hash, entry); 4422 return 0; 4423 } 4424 4425 return add_hash_entry(hash, ip); 4426 } 4427 4428 static int 4429 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len, 4430 unsigned long ip, int remove, int reset, int enable) 4431 { 4432 struct ftrace_hash **orig_hash; 4433 struct ftrace_hash *hash; 4434 int ret; 4435 4436 if (unlikely(ftrace_disabled)) 4437 return -ENODEV; 4438 4439 mutex_lock(&ops->func_hash->regex_lock); 4440 4441 if (enable) 4442 orig_hash = &ops->func_hash->filter_hash; 4443 else 4444 orig_hash = &ops->func_hash->notrace_hash; 4445 4446 if (reset) 4447 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); 4448 else 4449 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); 4450 4451 if (!hash) { 4452 ret = -ENOMEM; 4453 goto out_regex_unlock; 4454 } 4455 4456 if (buf && !ftrace_match_records(hash, buf, len)) { 4457 ret = -EINVAL; 4458 goto out_regex_unlock; 4459 } 4460 if (ip) { 4461 ret = ftrace_match_addr(hash, ip, remove); 4462 if (ret < 0) 4463 goto out_regex_unlock; 4464 } 4465 4466 mutex_lock(&ftrace_lock); 4467 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable); 4468 mutex_unlock(&ftrace_lock); 4469 4470 out_regex_unlock: 4471 mutex_unlock(&ops->func_hash->regex_lock); 4472 4473 free_ftrace_hash(hash); 4474 return ret; 4475 } 4476 4477 static int 4478 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove, 4479 int reset, int enable) 4480 { 4481 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable); 4482 } 4483 4484 /** 4485 * ftrace_set_filter_ip - set a function to filter on in ftrace by address 4486 * @ops - the ops to set the filter with 4487 * @ip - the address to add to or remove from the filter. 4488 * @remove - non zero to remove the ip from the filter 4489 * @reset - non zero to reset all filters before applying this filter. 4490 * 4491 * Filters denote which functions should be enabled when tracing is enabled 4492 * If @ip is NULL, it failes to update filter. 4493 */ 4494 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, 4495 int remove, int reset) 4496 { 4497 ftrace_ops_init(ops); 4498 return ftrace_set_addr(ops, ip, remove, reset, 1); 4499 } 4500 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip); 4501 4502 /** 4503 * ftrace_ops_set_global_filter - setup ops to use global filters 4504 * @ops - the ops which will use the global filters 4505 * 4506 * ftrace users who need global function trace filtering should call this. 4507 * It can set the global filter only if ops were not initialized before. 4508 */ 4509 void ftrace_ops_set_global_filter(struct ftrace_ops *ops) 4510 { 4511 if (ops->flags & FTRACE_OPS_FL_INITIALIZED) 4512 return; 4513 4514 ftrace_ops_init(ops); 4515 ops->func_hash = &global_ops.local_hash; 4516 } 4517 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter); 4518 4519 static int 4520 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, 4521 int reset, int enable) 4522 { 4523 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable); 4524 } 4525 4526 /** 4527 * ftrace_set_filter - set a function to filter on in ftrace 4528 * @ops - the ops to set the filter with 4529 * @buf - the string that holds the function filter text. 4530 * @len - the length of the string. 4531 * @reset - non zero to reset all filters before applying this filter. 4532 * 4533 * Filters denote which functions should be enabled when tracing is enabled. 4534 * If @buf is NULL and reset is set, all functions will be enabled for tracing. 4535 */ 4536 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, 4537 int len, int reset) 4538 { 4539 ftrace_ops_init(ops); 4540 return ftrace_set_regex(ops, buf, len, reset, 1); 4541 } 4542 EXPORT_SYMBOL_GPL(ftrace_set_filter); 4543 4544 /** 4545 * ftrace_set_notrace - set a function to not trace in ftrace 4546 * @ops - the ops to set the notrace filter with 4547 * @buf - the string that holds the function notrace text. 4548 * @len - the length of the string. 4549 * @reset - non zero to reset all filters before applying this filter. 4550 * 4551 * Notrace Filters denote which functions should not be enabled when tracing 4552 * is enabled. If @buf is NULL and reset is set, all functions will be enabled 4553 * for tracing. 4554 */ 4555 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, 4556 int len, int reset) 4557 { 4558 ftrace_ops_init(ops); 4559 return ftrace_set_regex(ops, buf, len, reset, 0); 4560 } 4561 EXPORT_SYMBOL_GPL(ftrace_set_notrace); 4562 /** 4563 * ftrace_set_global_filter - set a function to filter on with global tracers 4564 * @buf - the string that holds the function filter text. 4565 * @len - the length of the string. 4566 * @reset - non zero to reset all filters before applying this filter. 4567 * 4568 * Filters denote which functions should be enabled when tracing is enabled. 4569 * If @buf is NULL and reset is set, all functions will be enabled for tracing. 4570 */ 4571 void ftrace_set_global_filter(unsigned char *buf, int len, int reset) 4572 { 4573 ftrace_set_regex(&global_ops, buf, len, reset, 1); 4574 } 4575 EXPORT_SYMBOL_GPL(ftrace_set_global_filter); 4576 4577 /** 4578 * ftrace_set_global_notrace - set a function to not trace with global tracers 4579 * @buf - the string that holds the function notrace text. 4580 * @len - the length of the string. 4581 * @reset - non zero to reset all filters before applying this filter. 4582 * 4583 * Notrace Filters denote which functions should not be enabled when tracing 4584 * is enabled. If @buf is NULL and reset is set, all functions will be enabled 4585 * for tracing. 4586 */ 4587 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset) 4588 { 4589 ftrace_set_regex(&global_ops, buf, len, reset, 0); 4590 } 4591 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace); 4592 4593 /* 4594 * command line interface to allow users to set filters on boot up. 4595 */ 4596 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE 4597 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata; 4598 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata; 4599 4600 /* Used by function selftest to not test if filter is set */ 4601 bool ftrace_filter_param __initdata; 4602 4603 static int __init set_ftrace_notrace(char *str) 4604 { 4605 ftrace_filter_param = true; 4606 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE); 4607 return 1; 4608 } 4609 __setup("ftrace_notrace=", set_ftrace_notrace); 4610 4611 static int __init set_ftrace_filter(char *str) 4612 { 4613 ftrace_filter_param = true; 4614 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE); 4615 return 1; 4616 } 4617 __setup("ftrace_filter=", set_ftrace_filter); 4618 4619 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 4620 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; 4621 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata; 4622 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer); 4623 4624 static unsigned long save_global_trampoline; 4625 static unsigned long save_global_flags; 4626 4627 static int __init set_graph_function(char *str) 4628 { 4629 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); 4630 return 1; 4631 } 4632 __setup("ftrace_graph_filter=", set_graph_function); 4633 4634 static int __init set_graph_notrace_function(char *str) 4635 { 4636 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE); 4637 return 1; 4638 } 4639 __setup("ftrace_graph_notrace=", set_graph_notrace_function); 4640 4641 static int __init set_graph_max_depth_function(char *str) 4642 { 4643 if (!str) 4644 return 0; 4645 fgraph_max_depth = simple_strtoul(str, NULL, 0); 4646 return 1; 4647 } 4648 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function); 4649 4650 static void __init set_ftrace_early_graph(char *buf, int enable) 4651 { 4652 int ret; 4653 char *func; 4654 struct ftrace_hash *hash; 4655 4656 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); 4657 if (WARN_ON(!hash)) 4658 return; 4659 4660 while (buf) { 4661 func = strsep(&buf, ","); 4662 /* we allow only one expression at a time */ 4663 ret = ftrace_graph_set_hash(hash, func); 4664 if (ret) 4665 printk(KERN_DEBUG "ftrace: function %s not " 4666 "traceable\n", func); 4667 } 4668 4669 if (enable) 4670 ftrace_graph_hash = hash; 4671 else 4672 ftrace_graph_notrace_hash = hash; 4673 } 4674 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 4675 4676 void __init 4677 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable) 4678 { 4679 char *func; 4680 4681 ftrace_ops_init(ops); 4682 4683 while (buf) { 4684 func = strsep(&buf, ","); 4685 ftrace_set_regex(ops, func, strlen(func), 0, enable); 4686 } 4687 } 4688 4689 static void __init set_ftrace_early_filters(void) 4690 { 4691 if (ftrace_filter_buf[0]) 4692 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1); 4693 if (ftrace_notrace_buf[0]) 4694 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0); 4695 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 4696 if (ftrace_graph_buf[0]) 4697 set_ftrace_early_graph(ftrace_graph_buf, 1); 4698 if (ftrace_graph_notrace_buf[0]) 4699 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0); 4700 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 4701 } 4702 4703 int ftrace_regex_release(struct inode *inode, struct file *file) 4704 { 4705 struct seq_file *m = (struct seq_file *)file->private_data; 4706 struct ftrace_iterator *iter; 4707 struct ftrace_hash **orig_hash; 4708 struct trace_parser *parser; 4709 int filter_hash; 4710 int ret; 4711 4712 if (file->f_mode & FMODE_READ) { 4713 iter = m->private; 4714 seq_release(inode, file); 4715 } else 4716 iter = file->private_data; 4717 4718 parser = &iter->parser; 4719 if (trace_parser_loaded(parser)) { 4720 parser->buffer[parser->idx] = 0; 4721 ftrace_match_records(iter->hash, parser->buffer, parser->idx); 4722 } 4723 4724 trace_parser_put(parser); 4725 4726 mutex_lock(&iter->ops->func_hash->regex_lock); 4727 4728 if (file->f_mode & FMODE_WRITE) { 4729 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER); 4730 4731 if (filter_hash) 4732 orig_hash = &iter->ops->func_hash->filter_hash; 4733 else 4734 orig_hash = &iter->ops->func_hash->notrace_hash; 4735 4736 mutex_lock(&ftrace_lock); 4737 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash, 4738 iter->hash, filter_hash); 4739 mutex_unlock(&ftrace_lock); 4740 } else { 4741 /* For read only, the hash is the ops hash */ 4742 iter->hash = NULL; 4743 } 4744 4745 mutex_unlock(&iter->ops->func_hash->regex_lock); 4746 free_ftrace_hash(iter->hash); 4747 kfree(iter); 4748 4749 return 0; 4750 } 4751 4752 static const struct file_operations ftrace_avail_fops = { 4753 .open = ftrace_avail_open, 4754 .read = seq_read, 4755 .llseek = seq_lseek, 4756 .release = seq_release_private, 4757 }; 4758 4759 static const struct file_operations ftrace_enabled_fops = { 4760 .open = ftrace_enabled_open, 4761 .read = seq_read, 4762 .llseek = seq_lseek, 4763 .release = seq_release_private, 4764 }; 4765 4766 static const struct file_operations ftrace_filter_fops = { 4767 .open = ftrace_filter_open, 4768 .read = seq_read, 4769 .write = ftrace_filter_write, 4770 .llseek = tracing_lseek, 4771 .release = ftrace_regex_release, 4772 }; 4773 4774 static const struct file_operations ftrace_notrace_fops = { 4775 .open = ftrace_notrace_open, 4776 .read = seq_read, 4777 .write = ftrace_notrace_write, 4778 .llseek = tracing_lseek, 4779 .release = ftrace_regex_release, 4780 }; 4781 4782 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 4783 4784 static DEFINE_MUTEX(graph_lock); 4785 4786 struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH; 4787 struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH; 4788 4789 enum graph_filter_type { 4790 GRAPH_FILTER_NOTRACE = 0, 4791 GRAPH_FILTER_FUNCTION, 4792 }; 4793 4794 #define FTRACE_GRAPH_EMPTY ((void *)1) 4795 4796 struct ftrace_graph_data { 4797 struct ftrace_hash *hash; 4798 struct ftrace_func_entry *entry; 4799 int idx; /* for hash table iteration */ 4800 enum graph_filter_type type; 4801 struct ftrace_hash *new_hash; 4802 const struct seq_operations *seq_ops; 4803 struct trace_parser parser; 4804 }; 4805 4806 static void * 4807 __g_next(struct seq_file *m, loff_t *pos) 4808 { 4809 struct ftrace_graph_data *fgd = m->private; 4810 struct ftrace_func_entry *entry = fgd->entry; 4811 struct hlist_head *head; 4812 int i, idx = fgd->idx; 4813 4814 if (*pos >= fgd->hash->count) 4815 return NULL; 4816 4817 if (entry) { 4818 hlist_for_each_entry_continue(entry, hlist) { 4819 fgd->entry = entry; 4820 return entry; 4821 } 4822 4823 idx++; 4824 } 4825 4826 for (i = idx; i < 1 << fgd->hash->size_bits; i++) { 4827 head = &fgd->hash->buckets[i]; 4828 hlist_for_each_entry(entry, head, hlist) { 4829 fgd->entry = entry; 4830 fgd->idx = i; 4831 return entry; 4832 } 4833 } 4834 return NULL; 4835 } 4836 4837 static void * 4838 g_next(struct seq_file *m, void *v, loff_t *pos) 4839 { 4840 (*pos)++; 4841 return __g_next(m, pos); 4842 } 4843 4844 static void *g_start(struct seq_file *m, loff_t *pos) 4845 { 4846 struct ftrace_graph_data *fgd = m->private; 4847 4848 mutex_lock(&graph_lock); 4849 4850 if (fgd->type == GRAPH_FILTER_FUNCTION) 4851 fgd->hash = rcu_dereference_protected(ftrace_graph_hash, 4852 lockdep_is_held(&graph_lock)); 4853 else 4854 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash, 4855 lockdep_is_held(&graph_lock)); 4856 4857 /* Nothing, tell g_show to print all functions are enabled */ 4858 if (ftrace_hash_empty(fgd->hash) && !*pos) 4859 return FTRACE_GRAPH_EMPTY; 4860 4861 fgd->idx = 0; 4862 fgd->entry = NULL; 4863 return __g_next(m, pos); 4864 } 4865 4866 static void g_stop(struct seq_file *m, void *p) 4867 { 4868 mutex_unlock(&graph_lock); 4869 } 4870 4871 static int g_show(struct seq_file *m, void *v) 4872 { 4873 struct ftrace_func_entry *entry = v; 4874 4875 if (!entry) 4876 return 0; 4877 4878 if (entry == FTRACE_GRAPH_EMPTY) { 4879 struct ftrace_graph_data *fgd = m->private; 4880 4881 if (fgd->type == GRAPH_FILTER_FUNCTION) 4882 seq_puts(m, "#### all functions enabled ####\n"); 4883 else 4884 seq_puts(m, "#### no functions disabled ####\n"); 4885 return 0; 4886 } 4887 4888 seq_printf(m, "%ps\n", (void *)entry->ip); 4889 4890 return 0; 4891 } 4892 4893 static const struct seq_operations ftrace_graph_seq_ops = { 4894 .start = g_start, 4895 .next = g_next, 4896 .stop = g_stop, 4897 .show = g_show, 4898 }; 4899 4900 static int 4901 __ftrace_graph_open(struct inode *inode, struct file *file, 4902 struct ftrace_graph_data *fgd) 4903 { 4904 int ret = 0; 4905 struct ftrace_hash *new_hash = NULL; 4906 4907 if (file->f_mode & FMODE_WRITE) { 4908 const int size_bits = FTRACE_HASH_DEFAULT_BITS; 4909 4910 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX)) 4911 return -ENOMEM; 4912 4913 if (file->f_flags & O_TRUNC) 4914 new_hash = alloc_ftrace_hash(size_bits); 4915 else 4916 new_hash = alloc_and_copy_ftrace_hash(size_bits, 4917 fgd->hash); 4918 if (!new_hash) { 4919 ret = -ENOMEM; 4920 goto out; 4921 } 4922 } 4923 4924 if (file->f_mode & FMODE_READ) { 4925 ret = seq_open(file, &ftrace_graph_seq_ops); 4926 if (!ret) { 4927 struct seq_file *m = file->private_data; 4928 m->private = fgd; 4929 } else { 4930 /* Failed */ 4931 free_ftrace_hash(new_hash); 4932 new_hash = NULL; 4933 } 4934 } else 4935 file->private_data = fgd; 4936 4937 out: 4938 if (ret < 0 && file->f_mode & FMODE_WRITE) 4939 trace_parser_put(&fgd->parser); 4940 4941 fgd->new_hash = new_hash; 4942 4943 /* 4944 * All uses of fgd->hash must be taken with the graph_lock 4945 * held. The graph_lock is going to be released, so force 4946 * fgd->hash to be reinitialized when it is taken again. 4947 */ 4948 fgd->hash = NULL; 4949 4950 return ret; 4951 } 4952 4953 static int 4954 ftrace_graph_open(struct inode *inode, struct file *file) 4955 { 4956 struct ftrace_graph_data *fgd; 4957 int ret; 4958 4959 if (unlikely(ftrace_disabled)) 4960 return -ENODEV; 4961 4962 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL); 4963 if (fgd == NULL) 4964 return -ENOMEM; 4965 4966 mutex_lock(&graph_lock); 4967 4968 fgd->hash = rcu_dereference_protected(ftrace_graph_hash, 4969 lockdep_is_held(&graph_lock)); 4970 fgd->type = GRAPH_FILTER_FUNCTION; 4971 fgd->seq_ops = &ftrace_graph_seq_ops; 4972 4973 ret = __ftrace_graph_open(inode, file, fgd); 4974 if (ret < 0) 4975 kfree(fgd); 4976 4977 mutex_unlock(&graph_lock); 4978 return ret; 4979 } 4980 4981 static int 4982 ftrace_graph_notrace_open(struct inode *inode, struct file *file) 4983 { 4984 struct ftrace_graph_data *fgd; 4985 int ret; 4986 4987 if (unlikely(ftrace_disabled)) 4988 return -ENODEV; 4989 4990 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL); 4991 if (fgd == NULL) 4992 return -ENOMEM; 4993 4994 mutex_lock(&graph_lock); 4995 4996 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash, 4997 lockdep_is_held(&graph_lock)); 4998 fgd->type = GRAPH_FILTER_NOTRACE; 4999 fgd->seq_ops = &ftrace_graph_seq_ops; 5000 5001 ret = __ftrace_graph_open(inode, file, fgd); 5002 if (ret < 0) 5003 kfree(fgd); 5004 5005 mutex_unlock(&graph_lock); 5006 return ret; 5007 } 5008 5009 static int 5010 ftrace_graph_release(struct inode *inode, struct file *file) 5011 { 5012 struct ftrace_graph_data *fgd; 5013 struct ftrace_hash *old_hash, *new_hash; 5014 struct trace_parser *parser; 5015 int ret = 0; 5016 5017 if (file->f_mode & FMODE_READ) { 5018 struct seq_file *m = file->private_data; 5019 5020 fgd = m->private; 5021 seq_release(inode, file); 5022 } else { 5023 fgd = file->private_data; 5024 } 5025 5026 5027 if (file->f_mode & FMODE_WRITE) { 5028 5029 parser = &fgd->parser; 5030 5031 if (trace_parser_loaded((parser))) { 5032 parser->buffer[parser->idx] = 0; 5033 ret = ftrace_graph_set_hash(fgd->new_hash, 5034 parser->buffer); 5035 } 5036 5037 trace_parser_put(parser); 5038 5039 new_hash = __ftrace_hash_move(fgd->new_hash); 5040 if (!new_hash) { 5041 ret = -ENOMEM; 5042 goto out; 5043 } 5044 5045 mutex_lock(&graph_lock); 5046 5047 if (fgd->type == GRAPH_FILTER_FUNCTION) { 5048 old_hash = rcu_dereference_protected(ftrace_graph_hash, 5049 lockdep_is_held(&graph_lock)); 5050 rcu_assign_pointer(ftrace_graph_hash, new_hash); 5051 } else { 5052 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash, 5053 lockdep_is_held(&graph_lock)); 5054 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash); 5055 } 5056 5057 mutex_unlock(&graph_lock); 5058 5059 /* Wait till all users are no longer using the old hash */ 5060 synchronize_sched(); 5061 5062 free_ftrace_hash(old_hash); 5063 } 5064 5065 out: 5066 kfree(fgd->new_hash); 5067 kfree(fgd); 5068 5069 return ret; 5070 } 5071 5072 static int 5073 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer) 5074 { 5075 struct ftrace_glob func_g; 5076 struct dyn_ftrace *rec; 5077 struct ftrace_page *pg; 5078 struct ftrace_func_entry *entry; 5079 int fail = 1; 5080 int not; 5081 5082 /* decode regex */ 5083 func_g.type = filter_parse_regex(buffer, strlen(buffer), 5084 &func_g.search, ¬); 5085 5086 func_g.len = strlen(func_g.search); 5087 5088 mutex_lock(&ftrace_lock); 5089 5090 if (unlikely(ftrace_disabled)) { 5091 mutex_unlock(&ftrace_lock); 5092 return -ENODEV; 5093 } 5094 5095 do_for_each_ftrace_rec(pg, rec) { 5096 5097 if (rec->flags & FTRACE_FL_DISABLED) 5098 continue; 5099 5100 if (ftrace_match_record(rec, &func_g, NULL, 0)) { 5101 entry = ftrace_lookup_ip(hash, rec->ip); 5102 5103 if (!not) { 5104 fail = 0; 5105 5106 if (entry) 5107 continue; 5108 if (add_hash_entry(hash, rec->ip) < 0) 5109 goto out; 5110 } else { 5111 if (entry) { 5112 free_hash_entry(hash, entry); 5113 fail = 0; 5114 } 5115 } 5116 } 5117 } while_for_each_ftrace_rec(); 5118 out: 5119 mutex_unlock(&ftrace_lock); 5120 5121 if (fail) 5122 return -EINVAL; 5123 5124 return 0; 5125 } 5126 5127 static ssize_t 5128 ftrace_graph_write(struct file *file, const char __user *ubuf, 5129 size_t cnt, loff_t *ppos) 5130 { 5131 ssize_t read, ret = 0; 5132 struct ftrace_graph_data *fgd = file->private_data; 5133 struct trace_parser *parser; 5134 5135 if (!cnt) 5136 return 0; 5137 5138 /* Read mode uses seq functions */ 5139 if (file->f_mode & FMODE_READ) { 5140 struct seq_file *m = file->private_data; 5141 fgd = m->private; 5142 } 5143 5144 parser = &fgd->parser; 5145 5146 read = trace_get_user(parser, ubuf, cnt, ppos); 5147 5148 if (read >= 0 && trace_parser_loaded(parser) && 5149 !trace_parser_cont(parser)) { 5150 5151 ret = ftrace_graph_set_hash(fgd->new_hash, 5152 parser->buffer); 5153 trace_parser_clear(parser); 5154 } 5155 5156 if (!ret) 5157 ret = read; 5158 5159 return ret; 5160 } 5161 5162 static const struct file_operations ftrace_graph_fops = { 5163 .open = ftrace_graph_open, 5164 .read = seq_read, 5165 .write = ftrace_graph_write, 5166 .llseek = tracing_lseek, 5167 .release = ftrace_graph_release, 5168 }; 5169 5170 static const struct file_operations ftrace_graph_notrace_fops = { 5171 .open = ftrace_graph_notrace_open, 5172 .read = seq_read, 5173 .write = ftrace_graph_write, 5174 .llseek = tracing_lseek, 5175 .release = ftrace_graph_release, 5176 }; 5177 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 5178 5179 void ftrace_create_filter_files(struct ftrace_ops *ops, 5180 struct dentry *parent) 5181 { 5182 5183 trace_create_file("set_ftrace_filter", 0644, parent, 5184 ops, &ftrace_filter_fops); 5185 5186 trace_create_file("set_ftrace_notrace", 0644, parent, 5187 ops, &ftrace_notrace_fops); 5188 } 5189 5190 /* 5191 * The name "destroy_filter_files" is really a misnomer. Although 5192 * in the future, it may actualy delete the files, but this is 5193 * really intended to make sure the ops passed in are disabled 5194 * and that when this function returns, the caller is free to 5195 * free the ops. 5196 * 5197 * The "destroy" name is only to match the "create" name that this 5198 * should be paired with. 5199 */ 5200 void ftrace_destroy_filter_files(struct ftrace_ops *ops) 5201 { 5202 mutex_lock(&ftrace_lock); 5203 if (ops->flags & FTRACE_OPS_FL_ENABLED) 5204 ftrace_shutdown(ops, 0); 5205 ops->flags |= FTRACE_OPS_FL_DELETED; 5206 mutex_unlock(&ftrace_lock); 5207 } 5208 5209 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer) 5210 { 5211 5212 trace_create_file("available_filter_functions", 0444, 5213 d_tracer, NULL, &ftrace_avail_fops); 5214 5215 trace_create_file("enabled_functions", 0444, 5216 d_tracer, NULL, &ftrace_enabled_fops); 5217 5218 ftrace_create_filter_files(&global_ops, d_tracer); 5219 5220 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 5221 trace_create_file("set_graph_function", 0444, d_tracer, 5222 NULL, 5223 &ftrace_graph_fops); 5224 trace_create_file("set_graph_notrace", 0444, d_tracer, 5225 NULL, 5226 &ftrace_graph_notrace_fops); 5227 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 5228 5229 return 0; 5230 } 5231 5232 static int ftrace_cmp_ips(const void *a, const void *b) 5233 { 5234 const unsigned long *ipa = a; 5235 const unsigned long *ipb = b; 5236 5237 if (*ipa > *ipb) 5238 return 1; 5239 if (*ipa < *ipb) 5240 return -1; 5241 return 0; 5242 } 5243 5244 static int ftrace_process_locs(struct module *mod, 5245 unsigned long *start, 5246 unsigned long *end) 5247 { 5248 struct ftrace_page *start_pg; 5249 struct ftrace_page *pg; 5250 struct dyn_ftrace *rec; 5251 unsigned long count; 5252 unsigned long *p; 5253 unsigned long addr; 5254 unsigned long flags = 0; /* Shut up gcc */ 5255 int ret = -ENOMEM; 5256 5257 count = end - start; 5258 5259 if (!count) 5260 return 0; 5261 5262 sort(start, count, sizeof(*start), 5263 ftrace_cmp_ips, NULL); 5264 5265 start_pg = ftrace_allocate_pages(count); 5266 if (!start_pg) 5267 return -ENOMEM; 5268 5269 mutex_lock(&ftrace_lock); 5270 5271 /* 5272 * Core and each module needs their own pages, as 5273 * modules will free them when they are removed. 5274 * Force a new page to be allocated for modules. 5275 */ 5276 if (!mod) { 5277 WARN_ON(ftrace_pages || ftrace_pages_start); 5278 /* First initialization */ 5279 ftrace_pages = ftrace_pages_start = start_pg; 5280 } else { 5281 if (!ftrace_pages) 5282 goto out; 5283 5284 if (WARN_ON(ftrace_pages->next)) { 5285 /* Hmm, we have free pages? */ 5286 while (ftrace_pages->next) 5287 ftrace_pages = ftrace_pages->next; 5288 } 5289 5290 ftrace_pages->next = start_pg; 5291 } 5292 5293 p = start; 5294 pg = start_pg; 5295 while (p < end) { 5296 addr = ftrace_call_adjust(*p++); 5297 /* 5298 * Some architecture linkers will pad between 5299 * the different mcount_loc sections of different 5300 * object files to satisfy alignments. 5301 * Skip any NULL pointers. 5302 */ 5303 if (!addr) 5304 continue; 5305 5306 if (pg->index == pg->size) { 5307 /* We should have allocated enough */ 5308 if (WARN_ON(!pg->next)) 5309 break; 5310 pg = pg->next; 5311 } 5312 5313 rec = &pg->records[pg->index++]; 5314 rec->ip = addr; 5315 } 5316 5317 /* We should have used all pages */ 5318 WARN_ON(pg->next); 5319 5320 /* Assign the last page to ftrace_pages */ 5321 ftrace_pages = pg; 5322 5323 /* 5324 * We only need to disable interrupts on start up 5325 * because we are modifying code that an interrupt 5326 * may execute, and the modification is not atomic. 5327 * But for modules, nothing runs the code we modify 5328 * until we are finished with it, and there's no 5329 * reason to cause large interrupt latencies while we do it. 5330 */ 5331 if (!mod) 5332 local_irq_save(flags); 5333 ftrace_update_code(mod, start_pg); 5334 if (!mod) 5335 local_irq_restore(flags); 5336 ret = 0; 5337 out: 5338 mutex_unlock(&ftrace_lock); 5339 5340 return ret; 5341 } 5342 5343 #ifdef CONFIG_MODULES 5344 5345 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next) 5346 5347 static int referenced_filters(struct dyn_ftrace *rec) 5348 { 5349 struct ftrace_ops *ops; 5350 int cnt = 0; 5351 5352 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) { 5353 if (ops_references_rec(ops, rec)) 5354 cnt++; 5355 } 5356 5357 return cnt; 5358 } 5359 5360 void ftrace_release_mod(struct module *mod) 5361 { 5362 struct dyn_ftrace *rec; 5363 struct ftrace_page **last_pg; 5364 struct ftrace_page *pg; 5365 int order; 5366 5367 mutex_lock(&ftrace_lock); 5368 5369 if (ftrace_disabled) 5370 goto out_unlock; 5371 5372 /* 5373 * Each module has its own ftrace_pages, remove 5374 * them from the list. 5375 */ 5376 last_pg = &ftrace_pages_start; 5377 for (pg = ftrace_pages_start; pg; pg = *last_pg) { 5378 rec = &pg->records[0]; 5379 if (within_module_core(rec->ip, mod)) { 5380 /* 5381 * As core pages are first, the first 5382 * page should never be a module page. 5383 */ 5384 if (WARN_ON(pg == ftrace_pages_start)) 5385 goto out_unlock; 5386 5387 /* Check if we are deleting the last page */ 5388 if (pg == ftrace_pages) 5389 ftrace_pages = next_to_ftrace_page(last_pg); 5390 5391 *last_pg = pg->next; 5392 order = get_count_order(pg->size / ENTRIES_PER_PAGE); 5393 free_pages((unsigned long)pg->records, order); 5394 kfree(pg); 5395 } else 5396 last_pg = &pg->next; 5397 } 5398 out_unlock: 5399 mutex_unlock(&ftrace_lock); 5400 } 5401 5402 void ftrace_module_enable(struct module *mod) 5403 { 5404 struct dyn_ftrace *rec; 5405 struct ftrace_page *pg; 5406 5407 mutex_lock(&ftrace_lock); 5408 5409 if (ftrace_disabled) 5410 goto out_unlock; 5411 5412 /* 5413 * If the tracing is enabled, go ahead and enable the record. 5414 * 5415 * The reason not to enable the record immediatelly is the 5416 * inherent check of ftrace_make_nop/ftrace_make_call for 5417 * correct previous instructions. Making first the NOP 5418 * conversion puts the module to the correct state, thus 5419 * passing the ftrace_make_call check. 5420 * 5421 * We also delay this to after the module code already set the 5422 * text to read-only, as we now need to set it back to read-write 5423 * so that we can modify the text. 5424 */ 5425 if (ftrace_start_up) 5426 ftrace_arch_code_modify_prepare(); 5427 5428 do_for_each_ftrace_rec(pg, rec) { 5429 int cnt; 5430 /* 5431 * do_for_each_ftrace_rec() is a double loop. 5432 * module text shares the pg. If a record is 5433 * not part of this module, then skip this pg, 5434 * which the "break" will do. 5435 */ 5436 if (!within_module_core(rec->ip, mod)) 5437 break; 5438 5439 cnt = 0; 5440 5441 /* 5442 * When adding a module, we need to check if tracers are 5443 * currently enabled and if they are, and can trace this record, 5444 * we need to enable the module functions as well as update the 5445 * reference counts for those function records. 5446 */ 5447 if (ftrace_start_up) 5448 cnt += referenced_filters(rec); 5449 5450 /* This clears FTRACE_FL_DISABLED */ 5451 rec->flags = cnt; 5452 5453 if (ftrace_start_up && cnt) { 5454 int failed = __ftrace_replace_code(rec, 1); 5455 if (failed) { 5456 ftrace_bug(failed, rec); 5457 goto out_loop; 5458 } 5459 } 5460 5461 } while_for_each_ftrace_rec(); 5462 5463 out_loop: 5464 if (ftrace_start_up) 5465 ftrace_arch_code_modify_post_process(); 5466 5467 out_unlock: 5468 mutex_unlock(&ftrace_lock); 5469 } 5470 5471 void ftrace_module_init(struct module *mod) 5472 { 5473 if (ftrace_disabled || !mod->num_ftrace_callsites) 5474 return; 5475 5476 ftrace_process_locs(mod, mod->ftrace_callsites, 5477 mod->ftrace_callsites + mod->num_ftrace_callsites); 5478 } 5479 #endif /* CONFIG_MODULES */ 5480 5481 void __init ftrace_free_init_mem(void) 5482 { 5483 unsigned long start = (unsigned long)(&__init_begin); 5484 unsigned long end = (unsigned long)(&__init_end); 5485 struct ftrace_page **last_pg = &ftrace_pages_start; 5486 struct ftrace_page *pg; 5487 struct dyn_ftrace *rec; 5488 struct dyn_ftrace key; 5489 int order; 5490 5491 key.ip = start; 5492 key.flags = end; /* overload flags, as it is unsigned long */ 5493 5494 mutex_lock(&ftrace_lock); 5495 5496 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) { 5497 if (end < pg->records[0].ip || 5498 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE)) 5499 continue; 5500 again: 5501 rec = bsearch(&key, pg->records, pg->index, 5502 sizeof(struct dyn_ftrace), 5503 ftrace_cmp_recs); 5504 if (!rec) 5505 continue; 5506 pg->index--; 5507 if (!pg->index) { 5508 *last_pg = pg->next; 5509 order = get_count_order(pg->size / ENTRIES_PER_PAGE); 5510 free_pages((unsigned long)pg->records, order); 5511 kfree(pg); 5512 pg = container_of(last_pg, struct ftrace_page, next); 5513 if (!(*last_pg)) 5514 ftrace_pages = pg; 5515 continue; 5516 } 5517 memmove(rec, rec + 1, 5518 (pg->index - (rec - pg->records)) * sizeof(*rec)); 5519 /* More than one function may be in this block */ 5520 goto again; 5521 } 5522 mutex_unlock(&ftrace_lock); 5523 } 5524 5525 void __init ftrace_init(void) 5526 { 5527 extern unsigned long __start_mcount_loc[]; 5528 extern unsigned long __stop_mcount_loc[]; 5529 unsigned long count, flags; 5530 int ret; 5531 5532 local_irq_save(flags); 5533 ret = ftrace_dyn_arch_init(); 5534 local_irq_restore(flags); 5535 if (ret) 5536 goto failed; 5537 5538 count = __stop_mcount_loc - __start_mcount_loc; 5539 if (!count) { 5540 pr_info("ftrace: No functions to be traced?\n"); 5541 goto failed; 5542 } 5543 5544 pr_info("ftrace: allocating %ld entries in %ld pages\n", 5545 count, count / ENTRIES_PER_PAGE + 1); 5546 5547 last_ftrace_enabled = ftrace_enabled = 1; 5548 5549 ret = ftrace_process_locs(NULL, 5550 __start_mcount_loc, 5551 __stop_mcount_loc); 5552 5553 set_ftrace_early_filters(); 5554 5555 return; 5556 failed: 5557 ftrace_disabled = 1; 5558 } 5559 5560 /* Do nothing if arch does not support this */ 5561 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops) 5562 { 5563 } 5564 5565 static void ftrace_update_trampoline(struct ftrace_ops *ops) 5566 { 5567 arch_ftrace_update_trampoline(ops); 5568 } 5569 5570 void ftrace_init_trace_array(struct trace_array *tr) 5571 { 5572 INIT_LIST_HEAD(&tr->func_probes); 5573 } 5574 #else 5575 5576 static struct ftrace_ops global_ops = { 5577 .func = ftrace_stub, 5578 .flags = FTRACE_OPS_FL_RECURSION_SAFE | 5579 FTRACE_OPS_FL_INITIALIZED | 5580 FTRACE_OPS_FL_PID, 5581 }; 5582 5583 static int __init ftrace_nodyn_init(void) 5584 { 5585 ftrace_enabled = 1; 5586 return 0; 5587 } 5588 core_initcall(ftrace_nodyn_init); 5589 5590 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; } 5591 static inline void ftrace_startup_enable(int command) { } 5592 static inline void ftrace_startup_all(int command) { } 5593 /* Keep as macros so we do not need to define the commands */ 5594 # define ftrace_startup(ops, command) \ 5595 ({ \ 5596 int ___ret = __register_ftrace_function(ops); \ 5597 if (!___ret) \ 5598 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \ 5599 ___ret; \ 5600 }) 5601 # define ftrace_shutdown(ops, command) \ 5602 ({ \ 5603 int ___ret = __unregister_ftrace_function(ops); \ 5604 if (!___ret) \ 5605 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \ 5606 ___ret; \ 5607 }) 5608 5609 # define ftrace_startup_sysctl() do { } while (0) 5610 # define ftrace_shutdown_sysctl() do { } while (0) 5611 5612 static inline int 5613 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) 5614 { 5615 return 1; 5616 } 5617 5618 static void ftrace_update_trampoline(struct ftrace_ops *ops) 5619 { 5620 } 5621 5622 #endif /* CONFIG_DYNAMIC_FTRACE */ 5623 5624 __init void ftrace_init_global_array_ops(struct trace_array *tr) 5625 { 5626 tr->ops = &global_ops; 5627 tr->ops->private = tr; 5628 ftrace_init_trace_array(tr); 5629 } 5630 5631 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func) 5632 { 5633 /* If we filter on pids, update to use the pid function */ 5634 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) { 5635 if (WARN_ON(tr->ops->func != ftrace_stub)) 5636 printk("ftrace ops had %pS for function\n", 5637 tr->ops->func); 5638 } 5639 tr->ops->func = func; 5640 tr->ops->private = tr; 5641 } 5642 5643 void ftrace_reset_array_ops(struct trace_array *tr) 5644 { 5645 tr->ops->func = ftrace_stub; 5646 } 5647 5648 static inline void 5649 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, 5650 struct ftrace_ops *ignored, struct pt_regs *regs) 5651 { 5652 struct ftrace_ops *op; 5653 int bit; 5654 5655 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); 5656 if (bit < 0) 5657 return; 5658 5659 /* 5660 * Some of the ops may be dynamically allocated, 5661 * they must be freed after a synchronize_sched(). 5662 */ 5663 preempt_disable_notrace(); 5664 5665 do_for_each_ftrace_op(op, ftrace_ops_list) { 5666 /* 5667 * Check the following for each ops before calling their func: 5668 * if RCU flag is set, then rcu_is_watching() must be true 5669 * if PER_CPU is set, then ftrace_function_local_disable() 5670 * must be false 5671 * Otherwise test if the ip matches the ops filter 5672 * 5673 * If any of the above fails then the op->func() is not executed. 5674 */ 5675 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) && 5676 (!(op->flags & FTRACE_OPS_FL_PER_CPU) || 5677 !ftrace_function_local_disabled(op)) && 5678 ftrace_ops_test(op, ip, regs)) { 5679 5680 if (FTRACE_WARN_ON(!op->func)) { 5681 pr_warn("op=%p %pS\n", op, op); 5682 goto out; 5683 } 5684 op->func(ip, parent_ip, op, regs); 5685 } 5686 } while_for_each_ftrace_op(op); 5687 out: 5688 preempt_enable_notrace(); 5689 trace_clear_recursion(bit); 5690 } 5691 5692 /* 5693 * Some archs only support passing ip and parent_ip. Even though 5694 * the list function ignores the op parameter, we do not want any 5695 * C side effects, where a function is called without the caller 5696 * sending a third parameter. 5697 * Archs are to support both the regs and ftrace_ops at the same time. 5698 * If they support ftrace_ops, it is assumed they support regs. 5699 * If call backs want to use regs, they must either check for regs 5700 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS. 5701 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved. 5702 * An architecture can pass partial regs with ftrace_ops and still 5703 * set the ARCH_SUPPORTS_FTRACE_OPS. 5704 */ 5705 #if ARCH_SUPPORTS_FTRACE_OPS 5706 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, 5707 struct ftrace_ops *op, struct pt_regs *regs) 5708 { 5709 __ftrace_ops_list_func(ip, parent_ip, NULL, regs); 5710 } 5711 #else 5712 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip) 5713 { 5714 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL); 5715 } 5716 #endif 5717 5718 /* 5719 * If there's only one function registered but it does not support 5720 * recursion, needs RCU protection and/or requires per cpu handling, then 5721 * this function will be called by the mcount trampoline. 5722 */ 5723 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip, 5724 struct ftrace_ops *op, struct pt_regs *regs) 5725 { 5726 int bit; 5727 5728 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching()) 5729 return; 5730 5731 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); 5732 if (bit < 0) 5733 return; 5734 5735 preempt_disable_notrace(); 5736 5737 if (!(op->flags & FTRACE_OPS_FL_PER_CPU) || 5738 !ftrace_function_local_disabled(op)) { 5739 op->func(ip, parent_ip, op, regs); 5740 } 5741 5742 preempt_enable_notrace(); 5743 trace_clear_recursion(bit); 5744 } 5745 5746 /** 5747 * ftrace_ops_get_func - get the function a trampoline should call 5748 * @ops: the ops to get the function for 5749 * 5750 * Normally the mcount trampoline will call the ops->func, but there 5751 * are times that it should not. For example, if the ops does not 5752 * have its own recursion protection, then it should call the 5753 * ftrace_ops_assist_func() instead. 5754 * 5755 * Returns the function that the trampoline should call for @ops. 5756 */ 5757 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops) 5758 { 5759 /* 5760 * If the function does not handle recursion, needs to be RCU safe, 5761 * or does per cpu logic, then we need to call the assist handler. 5762 */ 5763 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) || 5764 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU)) 5765 return ftrace_ops_assist_func; 5766 5767 return ops->func; 5768 } 5769 5770 static void 5771 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt, 5772 struct task_struct *prev, struct task_struct *next) 5773 { 5774 struct trace_array *tr = data; 5775 struct trace_pid_list *pid_list; 5776 5777 pid_list = rcu_dereference_sched(tr->function_pids); 5778 5779 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid, 5780 trace_ignore_this_task(pid_list, next)); 5781 } 5782 5783 static void 5784 ftrace_pid_follow_sched_process_fork(void *data, 5785 struct task_struct *self, 5786 struct task_struct *task) 5787 { 5788 struct trace_pid_list *pid_list; 5789 struct trace_array *tr = data; 5790 5791 pid_list = rcu_dereference_sched(tr->function_pids); 5792 trace_filter_add_remove_task(pid_list, self, task); 5793 } 5794 5795 static void 5796 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task) 5797 { 5798 struct trace_pid_list *pid_list; 5799 struct trace_array *tr = data; 5800 5801 pid_list = rcu_dereference_sched(tr->function_pids); 5802 trace_filter_add_remove_task(pid_list, NULL, task); 5803 } 5804 5805 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable) 5806 { 5807 if (enable) { 5808 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork, 5809 tr); 5810 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit, 5811 tr); 5812 } else { 5813 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork, 5814 tr); 5815 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit, 5816 tr); 5817 } 5818 } 5819 5820 static void clear_ftrace_pids(struct trace_array *tr) 5821 { 5822 struct trace_pid_list *pid_list; 5823 int cpu; 5824 5825 pid_list = rcu_dereference_protected(tr->function_pids, 5826 lockdep_is_held(&ftrace_lock)); 5827 if (!pid_list) 5828 return; 5829 5830 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr); 5831 5832 for_each_possible_cpu(cpu) 5833 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false; 5834 5835 rcu_assign_pointer(tr->function_pids, NULL); 5836 5837 /* Wait till all users are no longer using pid filtering */ 5838 synchronize_sched(); 5839 5840 trace_free_pid_list(pid_list); 5841 } 5842 5843 void ftrace_clear_pids(struct trace_array *tr) 5844 { 5845 mutex_lock(&ftrace_lock); 5846 5847 clear_ftrace_pids(tr); 5848 5849 mutex_unlock(&ftrace_lock); 5850 } 5851 5852 static void ftrace_pid_reset(struct trace_array *tr) 5853 { 5854 mutex_lock(&ftrace_lock); 5855 clear_ftrace_pids(tr); 5856 5857 ftrace_update_pid_func(); 5858 ftrace_startup_all(0); 5859 5860 mutex_unlock(&ftrace_lock); 5861 } 5862 5863 /* Greater than any max PID */ 5864 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1) 5865 5866 static void *fpid_start(struct seq_file *m, loff_t *pos) 5867 __acquires(RCU) 5868 { 5869 struct trace_pid_list *pid_list; 5870 struct trace_array *tr = m->private; 5871 5872 mutex_lock(&ftrace_lock); 5873 rcu_read_lock_sched(); 5874 5875 pid_list = rcu_dereference_sched(tr->function_pids); 5876 5877 if (!pid_list) 5878 return !(*pos) ? FTRACE_NO_PIDS : NULL; 5879 5880 return trace_pid_start(pid_list, pos); 5881 } 5882 5883 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos) 5884 { 5885 struct trace_array *tr = m->private; 5886 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids); 5887 5888 if (v == FTRACE_NO_PIDS) 5889 return NULL; 5890 5891 return trace_pid_next(pid_list, v, pos); 5892 } 5893 5894 static void fpid_stop(struct seq_file *m, void *p) 5895 __releases(RCU) 5896 { 5897 rcu_read_unlock_sched(); 5898 mutex_unlock(&ftrace_lock); 5899 } 5900 5901 static int fpid_show(struct seq_file *m, void *v) 5902 { 5903 if (v == FTRACE_NO_PIDS) { 5904 seq_puts(m, "no pid\n"); 5905 return 0; 5906 } 5907 5908 return trace_pid_show(m, v); 5909 } 5910 5911 static const struct seq_operations ftrace_pid_sops = { 5912 .start = fpid_start, 5913 .next = fpid_next, 5914 .stop = fpid_stop, 5915 .show = fpid_show, 5916 }; 5917 5918 static int 5919 ftrace_pid_open(struct inode *inode, struct file *file) 5920 { 5921 struct trace_array *tr = inode->i_private; 5922 struct seq_file *m; 5923 int ret = 0; 5924 5925 if (trace_array_get(tr) < 0) 5926 return -ENODEV; 5927 5928 if ((file->f_mode & FMODE_WRITE) && 5929 (file->f_flags & O_TRUNC)) 5930 ftrace_pid_reset(tr); 5931 5932 ret = seq_open(file, &ftrace_pid_sops); 5933 if (ret < 0) { 5934 trace_array_put(tr); 5935 } else { 5936 m = file->private_data; 5937 /* copy tr over to seq ops */ 5938 m->private = tr; 5939 } 5940 5941 return ret; 5942 } 5943 5944 static void ignore_task_cpu(void *data) 5945 { 5946 struct trace_array *tr = data; 5947 struct trace_pid_list *pid_list; 5948 5949 /* 5950 * This function is called by on_each_cpu() while the 5951 * event_mutex is held. 5952 */ 5953 pid_list = rcu_dereference_protected(tr->function_pids, 5954 mutex_is_locked(&ftrace_lock)); 5955 5956 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid, 5957 trace_ignore_this_task(pid_list, current)); 5958 } 5959 5960 static ssize_t 5961 ftrace_pid_write(struct file *filp, const char __user *ubuf, 5962 size_t cnt, loff_t *ppos) 5963 { 5964 struct seq_file *m = filp->private_data; 5965 struct trace_array *tr = m->private; 5966 struct trace_pid_list *filtered_pids = NULL; 5967 struct trace_pid_list *pid_list; 5968 ssize_t ret; 5969 5970 if (!cnt) 5971 return 0; 5972 5973 mutex_lock(&ftrace_lock); 5974 5975 filtered_pids = rcu_dereference_protected(tr->function_pids, 5976 lockdep_is_held(&ftrace_lock)); 5977 5978 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt); 5979 if (ret < 0) 5980 goto out; 5981 5982 rcu_assign_pointer(tr->function_pids, pid_list); 5983 5984 if (filtered_pids) { 5985 synchronize_sched(); 5986 trace_free_pid_list(filtered_pids); 5987 } else if (pid_list) { 5988 /* Register a probe to set whether to ignore the tracing of a task */ 5989 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr); 5990 } 5991 5992 /* 5993 * Ignoring of pids is done at task switch. But we have to 5994 * check for those tasks that are currently running. 5995 * Always do this in case a pid was appended or removed. 5996 */ 5997 on_each_cpu(ignore_task_cpu, tr, 1); 5998 5999 ftrace_update_pid_func(); 6000 ftrace_startup_all(0); 6001 out: 6002 mutex_unlock(&ftrace_lock); 6003 6004 if (ret > 0) 6005 *ppos += ret; 6006 6007 return ret; 6008 } 6009 6010 static int 6011 ftrace_pid_release(struct inode *inode, struct file *file) 6012 { 6013 struct trace_array *tr = inode->i_private; 6014 6015 trace_array_put(tr); 6016 6017 return seq_release(inode, file); 6018 } 6019 6020 static const struct file_operations ftrace_pid_fops = { 6021 .open = ftrace_pid_open, 6022 .write = ftrace_pid_write, 6023 .read = seq_read, 6024 .llseek = tracing_lseek, 6025 .release = ftrace_pid_release, 6026 }; 6027 6028 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer) 6029 { 6030 trace_create_file("set_ftrace_pid", 0644, d_tracer, 6031 tr, &ftrace_pid_fops); 6032 } 6033 6034 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr, 6035 struct dentry *d_tracer) 6036 { 6037 /* Only the top level directory has the dyn_tracefs and profile */ 6038 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL)); 6039 6040 ftrace_init_dyn_tracefs(d_tracer); 6041 ftrace_profile_tracefs(d_tracer); 6042 } 6043 6044 /** 6045 * ftrace_kill - kill ftrace 6046 * 6047 * This function should be used by panic code. It stops ftrace 6048 * but in a not so nice way. If you need to simply kill ftrace 6049 * from a non-atomic section, use ftrace_kill. 6050 */ 6051 void ftrace_kill(void) 6052 { 6053 ftrace_disabled = 1; 6054 ftrace_enabled = 0; 6055 clear_ftrace_function(); 6056 } 6057 6058 /** 6059 * Test if ftrace is dead or not. 6060 */ 6061 int ftrace_is_dead(void) 6062 { 6063 return ftrace_disabled; 6064 } 6065 6066 /** 6067 * register_ftrace_function - register a function for profiling 6068 * @ops - ops structure that holds the function for profiling. 6069 * 6070 * Register a function to be called by all functions in the 6071 * kernel. 6072 * 6073 * Note: @ops->func and all the functions it calls must be labeled 6074 * with "notrace", otherwise it will go into a 6075 * recursive loop. 6076 */ 6077 int register_ftrace_function(struct ftrace_ops *ops) 6078 { 6079 int ret = -1; 6080 6081 ftrace_ops_init(ops); 6082 6083 mutex_lock(&ftrace_lock); 6084 6085 ret = ftrace_startup(ops, 0); 6086 6087 mutex_unlock(&ftrace_lock); 6088 6089 return ret; 6090 } 6091 EXPORT_SYMBOL_GPL(register_ftrace_function); 6092 6093 /** 6094 * unregister_ftrace_function - unregister a function for profiling. 6095 * @ops - ops structure that holds the function to unregister 6096 * 6097 * Unregister a function that was added to be called by ftrace profiling. 6098 */ 6099 int unregister_ftrace_function(struct ftrace_ops *ops) 6100 { 6101 int ret; 6102 6103 mutex_lock(&ftrace_lock); 6104 ret = ftrace_shutdown(ops, 0); 6105 mutex_unlock(&ftrace_lock); 6106 6107 return ret; 6108 } 6109 EXPORT_SYMBOL_GPL(unregister_ftrace_function); 6110 6111 int 6112 ftrace_enable_sysctl(struct ctl_table *table, int write, 6113 void __user *buffer, size_t *lenp, 6114 loff_t *ppos) 6115 { 6116 int ret = -ENODEV; 6117 6118 mutex_lock(&ftrace_lock); 6119 6120 if (unlikely(ftrace_disabled)) 6121 goto out; 6122 6123 ret = proc_dointvec(table, write, buffer, lenp, ppos); 6124 6125 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) 6126 goto out; 6127 6128 last_ftrace_enabled = !!ftrace_enabled; 6129 6130 if (ftrace_enabled) { 6131 6132 /* we are starting ftrace again */ 6133 if (ftrace_ops_list != &ftrace_list_end) 6134 update_ftrace_function(); 6135 6136 ftrace_startup_sysctl(); 6137 6138 } else { 6139 /* stopping ftrace calls (just send to ftrace_stub) */ 6140 ftrace_trace_function = ftrace_stub; 6141 6142 ftrace_shutdown_sysctl(); 6143 } 6144 6145 out: 6146 mutex_unlock(&ftrace_lock); 6147 return ret; 6148 } 6149 6150 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 6151 6152 static struct ftrace_ops graph_ops = { 6153 .func = ftrace_stub, 6154 .flags = FTRACE_OPS_FL_RECURSION_SAFE | 6155 FTRACE_OPS_FL_INITIALIZED | 6156 FTRACE_OPS_FL_PID | 6157 FTRACE_OPS_FL_STUB, 6158 #ifdef FTRACE_GRAPH_TRAMP_ADDR 6159 .trampoline = FTRACE_GRAPH_TRAMP_ADDR, 6160 /* trampoline_size is only needed for dynamically allocated tramps */ 6161 #endif 6162 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash) 6163 }; 6164 6165 void ftrace_graph_sleep_time_control(bool enable) 6166 { 6167 fgraph_sleep_time = enable; 6168 } 6169 6170 void ftrace_graph_graph_time_control(bool enable) 6171 { 6172 fgraph_graph_time = enable; 6173 } 6174 6175 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace) 6176 { 6177 return 0; 6178 } 6179 6180 /* The callbacks that hook a function */ 6181 trace_func_graph_ret_t ftrace_graph_return = 6182 (trace_func_graph_ret_t)ftrace_stub; 6183 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub; 6184 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub; 6185 6186 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */ 6187 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) 6188 { 6189 int i; 6190 int ret = 0; 6191 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE; 6192 struct task_struct *g, *t; 6193 6194 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) { 6195 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH 6196 * sizeof(struct ftrace_ret_stack), 6197 GFP_KERNEL); 6198 if (!ret_stack_list[i]) { 6199 start = 0; 6200 end = i; 6201 ret = -ENOMEM; 6202 goto free; 6203 } 6204 } 6205 6206 read_lock(&tasklist_lock); 6207 do_each_thread(g, t) { 6208 if (start == end) { 6209 ret = -EAGAIN; 6210 goto unlock; 6211 } 6212 6213 if (t->ret_stack == NULL) { 6214 atomic_set(&t->tracing_graph_pause, 0); 6215 atomic_set(&t->trace_overrun, 0); 6216 t->curr_ret_stack = -1; 6217 /* Make sure the tasks see the -1 first: */ 6218 smp_wmb(); 6219 t->ret_stack = ret_stack_list[start++]; 6220 } 6221 } while_each_thread(g, t); 6222 6223 unlock: 6224 read_unlock(&tasklist_lock); 6225 free: 6226 for (i = start; i < end; i++) 6227 kfree(ret_stack_list[i]); 6228 return ret; 6229 } 6230 6231 static void 6232 ftrace_graph_probe_sched_switch(void *ignore, bool preempt, 6233 struct task_struct *prev, struct task_struct *next) 6234 { 6235 unsigned long long timestamp; 6236 int index; 6237 6238 /* 6239 * Does the user want to count the time a function was asleep. 6240 * If so, do not update the time stamps. 6241 */ 6242 if (fgraph_sleep_time) 6243 return; 6244 6245 timestamp = trace_clock_local(); 6246 6247 prev->ftrace_timestamp = timestamp; 6248 6249 /* only process tasks that we timestamped */ 6250 if (!next->ftrace_timestamp) 6251 return; 6252 6253 /* 6254 * Update all the counters in next to make up for the 6255 * time next was sleeping. 6256 */ 6257 timestamp -= next->ftrace_timestamp; 6258 6259 for (index = next->curr_ret_stack; index >= 0; index--) 6260 next->ret_stack[index].calltime += timestamp; 6261 } 6262 6263 /* Allocate a return stack for each task */ 6264 static int start_graph_tracing(void) 6265 { 6266 struct ftrace_ret_stack **ret_stack_list; 6267 int ret, cpu; 6268 6269 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE * 6270 sizeof(struct ftrace_ret_stack *), 6271 GFP_KERNEL); 6272 6273 if (!ret_stack_list) 6274 return -ENOMEM; 6275 6276 /* The cpu_boot init_task->ret_stack will never be freed */ 6277 for_each_online_cpu(cpu) { 6278 if (!idle_task(cpu)->ret_stack) 6279 ftrace_graph_init_idle_task(idle_task(cpu), cpu); 6280 } 6281 6282 do { 6283 ret = alloc_retstack_tasklist(ret_stack_list); 6284 } while (ret == -EAGAIN); 6285 6286 if (!ret) { 6287 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); 6288 if (ret) 6289 pr_info("ftrace_graph: Couldn't activate tracepoint" 6290 " probe to kernel_sched_switch\n"); 6291 } 6292 6293 kfree(ret_stack_list); 6294 return ret; 6295 } 6296 6297 /* 6298 * Hibernation protection. 6299 * The state of the current task is too much unstable during 6300 * suspend/restore to disk. We want to protect against that. 6301 */ 6302 static int 6303 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state, 6304 void *unused) 6305 { 6306 switch (state) { 6307 case PM_HIBERNATION_PREPARE: 6308 pause_graph_tracing(); 6309 break; 6310 6311 case PM_POST_HIBERNATION: 6312 unpause_graph_tracing(); 6313 break; 6314 } 6315 return NOTIFY_DONE; 6316 } 6317 6318 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace) 6319 { 6320 if (!ftrace_ops_test(&global_ops, trace->func, NULL)) 6321 return 0; 6322 return __ftrace_graph_entry(trace); 6323 } 6324 6325 /* 6326 * The function graph tracer should only trace the functions defined 6327 * by set_ftrace_filter and set_ftrace_notrace. If another function 6328 * tracer ops is registered, the graph tracer requires testing the 6329 * function against the global ops, and not just trace any function 6330 * that any ftrace_ops registered. 6331 */ 6332 static void update_function_graph_func(void) 6333 { 6334 struct ftrace_ops *op; 6335 bool do_test = false; 6336 6337 /* 6338 * The graph and global ops share the same set of functions 6339 * to test. If any other ops is on the list, then 6340 * the graph tracing needs to test if its the function 6341 * it should call. 6342 */ 6343 do_for_each_ftrace_op(op, ftrace_ops_list) { 6344 if (op != &global_ops && op != &graph_ops && 6345 op != &ftrace_list_end) { 6346 do_test = true; 6347 /* in double loop, break out with goto */ 6348 goto out; 6349 } 6350 } while_for_each_ftrace_op(op); 6351 out: 6352 if (do_test) 6353 ftrace_graph_entry = ftrace_graph_entry_test; 6354 else 6355 ftrace_graph_entry = __ftrace_graph_entry; 6356 } 6357 6358 static struct notifier_block ftrace_suspend_notifier = { 6359 .notifier_call = ftrace_suspend_notifier_call, 6360 }; 6361 6362 int register_ftrace_graph(trace_func_graph_ret_t retfunc, 6363 trace_func_graph_ent_t entryfunc) 6364 { 6365 int ret = 0; 6366 6367 mutex_lock(&ftrace_lock); 6368 6369 /* we currently allow only one tracer registered at a time */ 6370 if (ftrace_graph_active) { 6371 ret = -EBUSY; 6372 goto out; 6373 } 6374 6375 register_pm_notifier(&ftrace_suspend_notifier); 6376 6377 ftrace_graph_active++; 6378 ret = start_graph_tracing(); 6379 if (ret) { 6380 ftrace_graph_active--; 6381 goto out; 6382 } 6383 6384 ftrace_graph_return = retfunc; 6385 6386 /* 6387 * Update the indirect function to the entryfunc, and the 6388 * function that gets called to the entry_test first. Then 6389 * call the update fgraph entry function to determine if 6390 * the entryfunc should be called directly or not. 6391 */ 6392 __ftrace_graph_entry = entryfunc; 6393 ftrace_graph_entry = ftrace_graph_entry_test; 6394 update_function_graph_func(); 6395 6396 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET); 6397 out: 6398 mutex_unlock(&ftrace_lock); 6399 return ret; 6400 } 6401 6402 void unregister_ftrace_graph(void) 6403 { 6404 mutex_lock(&ftrace_lock); 6405 6406 if (unlikely(!ftrace_graph_active)) 6407 goto out; 6408 6409 ftrace_graph_active--; 6410 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub; 6411 ftrace_graph_entry = ftrace_graph_entry_stub; 6412 __ftrace_graph_entry = ftrace_graph_entry_stub; 6413 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET); 6414 unregister_pm_notifier(&ftrace_suspend_notifier); 6415 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); 6416 6417 #ifdef CONFIG_DYNAMIC_FTRACE 6418 /* 6419 * Function graph does not allocate the trampoline, but 6420 * other global_ops do. We need to reset the ALLOC_TRAMP flag 6421 * if one was used. 6422 */ 6423 global_ops.trampoline = save_global_trampoline; 6424 if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP) 6425 global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP; 6426 #endif 6427 6428 out: 6429 mutex_unlock(&ftrace_lock); 6430 } 6431 6432 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack); 6433 6434 static void 6435 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack) 6436 { 6437 atomic_set(&t->tracing_graph_pause, 0); 6438 atomic_set(&t->trace_overrun, 0); 6439 t->ftrace_timestamp = 0; 6440 /* make curr_ret_stack visible before we add the ret_stack */ 6441 smp_wmb(); 6442 t->ret_stack = ret_stack; 6443 } 6444 6445 /* 6446 * Allocate a return stack for the idle task. May be the first 6447 * time through, or it may be done by CPU hotplug online. 6448 */ 6449 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) 6450 { 6451 t->curr_ret_stack = -1; 6452 /* 6453 * The idle task has no parent, it either has its own 6454 * stack or no stack at all. 6455 */ 6456 if (t->ret_stack) 6457 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu)); 6458 6459 if (ftrace_graph_active) { 6460 struct ftrace_ret_stack *ret_stack; 6461 6462 ret_stack = per_cpu(idle_ret_stack, cpu); 6463 if (!ret_stack) { 6464 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH 6465 * sizeof(struct ftrace_ret_stack), 6466 GFP_KERNEL); 6467 if (!ret_stack) 6468 return; 6469 per_cpu(idle_ret_stack, cpu) = ret_stack; 6470 } 6471 graph_init_task(t, ret_stack); 6472 } 6473 } 6474 6475 /* Allocate a return stack for newly created task */ 6476 void ftrace_graph_init_task(struct task_struct *t) 6477 { 6478 /* Make sure we do not use the parent ret_stack */ 6479 t->ret_stack = NULL; 6480 t->curr_ret_stack = -1; 6481 6482 if (ftrace_graph_active) { 6483 struct ftrace_ret_stack *ret_stack; 6484 6485 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH 6486 * sizeof(struct ftrace_ret_stack), 6487 GFP_KERNEL); 6488 if (!ret_stack) 6489 return; 6490 graph_init_task(t, ret_stack); 6491 } 6492 } 6493 6494 void ftrace_graph_exit_task(struct task_struct *t) 6495 { 6496 struct ftrace_ret_stack *ret_stack = t->ret_stack; 6497 6498 t->ret_stack = NULL; 6499 /* NULL must become visible to IRQs before we free it: */ 6500 barrier(); 6501 6502 kfree(ret_stack); 6503 } 6504 #endif 6505