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 __rcu *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 = rcu_dereference_protected(ftrace_ops_list, 173 lockdep_is_held(&ftrace_lock)); 174 ops != &ftrace_list_end; 175 ops = rcu_dereference_protected(ops->next, 176 lockdep_is_held(&ftrace_lock))) 177 cnt++; 178 179 mutex_unlock(&ftrace_lock); 180 181 return cnt; 182 } 183 184 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, 185 struct ftrace_ops *op, struct pt_regs *regs) 186 { 187 struct trace_array *tr = op->private; 188 189 if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid)) 190 return; 191 192 op->saved_func(ip, parent_ip, op, regs); 193 } 194 195 /** 196 * clear_ftrace_function - reset the ftrace function 197 * 198 * This NULLs the ftrace function and in essence stops 199 * tracing. There may be lag 200 */ 201 void clear_ftrace_function(void) 202 { 203 ftrace_trace_function = ftrace_stub; 204 } 205 206 static void per_cpu_ops_disable_all(struct ftrace_ops *ops) 207 { 208 int cpu; 209 210 for_each_possible_cpu(cpu) 211 *per_cpu_ptr(ops->disabled, cpu) = 1; 212 } 213 214 static int per_cpu_ops_alloc(struct ftrace_ops *ops) 215 { 216 int __percpu *disabled; 217 218 if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU))) 219 return -EINVAL; 220 221 disabled = alloc_percpu(int); 222 if (!disabled) 223 return -ENOMEM; 224 225 ops->disabled = disabled; 226 per_cpu_ops_disable_all(ops); 227 return 0; 228 } 229 230 static void ftrace_sync(struct work_struct *work) 231 { 232 /* 233 * This function is just a stub to implement a hard force 234 * of synchronize_sched(). This requires synchronizing 235 * tasks even in userspace and idle. 236 * 237 * Yes, function tracing is rude. 238 */ 239 } 240 241 static void ftrace_sync_ipi(void *data) 242 { 243 /* Probably not needed, but do it anyway */ 244 smp_rmb(); 245 } 246 247 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 248 static void update_function_graph_func(void); 249 250 /* Both enabled by default (can be cleared by function_graph tracer flags */ 251 static bool fgraph_sleep_time = true; 252 static bool fgraph_graph_time = true; 253 254 #else 255 static inline void update_function_graph_func(void) { } 256 #endif 257 258 259 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops) 260 { 261 /* 262 * If this is a dynamic, RCU, or per CPU ops, or we force list func, 263 * then it needs to call the list anyway. 264 */ 265 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU | 266 FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC) 267 return ftrace_ops_list_func; 268 269 return ftrace_ops_get_func(ops); 270 } 271 272 static void update_ftrace_function(void) 273 { 274 ftrace_func_t func; 275 276 /* 277 * Prepare the ftrace_ops that the arch callback will use. 278 * If there's only one ftrace_ops registered, the ftrace_ops_list 279 * will point to the ops we want. 280 */ 281 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list, 282 lockdep_is_held(&ftrace_lock)); 283 284 /* If there's no ftrace_ops registered, just call the stub function */ 285 if (set_function_trace_op == &ftrace_list_end) { 286 func = ftrace_stub; 287 288 /* 289 * If we are at the end of the list and this ops is 290 * recursion safe and not dynamic and the arch supports passing ops, 291 * then have the mcount trampoline call the function directly. 292 */ 293 } else if (rcu_dereference_protected(ftrace_ops_list->next, 294 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) { 295 func = ftrace_ops_get_list_func(ftrace_ops_list); 296 297 } else { 298 /* Just use the default ftrace_ops */ 299 set_function_trace_op = &ftrace_list_end; 300 func = ftrace_ops_list_func; 301 } 302 303 update_function_graph_func(); 304 305 /* If there's no change, then do nothing more here */ 306 if (ftrace_trace_function == func) 307 return; 308 309 /* 310 * If we are using the list function, it doesn't care 311 * about the function_trace_ops. 312 */ 313 if (func == ftrace_ops_list_func) { 314 ftrace_trace_function = func; 315 /* 316 * Don't even bother setting function_trace_ops, 317 * it would be racy to do so anyway. 318 */ 319 return; 320 } 321 322 #ifndef CONFIG_DYNAMIC_FTRACE 323 /* 324 * For static tracing, we need to be a bit more careful. 325 * The function change takes affect immediately. Thus, 326 * we need to coorditate the setting of the function_trace_ops 327 * with the setting of the ftrace_trace_function. 328 * 329 * Set the function to the list ops, which will call the 330 * function we want, albeit indirectly, but it handles the 331 * ftrace_ops and doesn't depend on function_trace_op. 332 */ 333 ftrace_trace_function = ftrace_ops_list_func; 334 /* 335 * Make sure all CPUs see this. Yes this is slow, but static 336 * tracing is slow and nasty to have enabled. 337 */ 338 schedule_on_each_cpu(ftrace_sync); 339 /* Now all cpus are using the list ops. */ 340 function_trace_op = set_function_trace_op; 341 /* Make sure the function_trace_op is visible on all CPUs */ 342 smp_wmb(); 343 /* Nasty way to force a rmb on all cpus */ 344 smp_call_function(ftrace_sync_ipi, NULL, 1); 345 /* OK, we are all set to update the ftrace_trace_function now! */ 346 #endif /* !CONFIG_DYNAMIC_FTRACE */ 347 348 ftrace_trace_function = func; 349 } 350 351 int using_ftrace_ops_list_func(void) 352 { 353 return ftrace_trace_function == ftrace_ops_list_func; 354 } 355 356 static void add_ftrace_ops(struct ftrace_ops __rcu **list, 357 struct ftrace_ops *ops) 358 { 359 rcu_assign_pointer(ops->next, *list); 360 361 /* 362 * We are entering ops into the list but another 363 * CPU might be walking that list. We need to make sure 364 * the ops->next pointer is valid before another CPU sees 365 * the ops pointer included into the list. 366 */ 367 rcu_assign_pointer(*list, ops); 368 } 369 370 static int remove_ftrace_ops(struct ftrace_ops __rcu **list, 371 struct ftrace_ops *ops) 372 { 373 struct ftrace_ops **p; 374 375 /* 376 * If we are removing the last function, then simply point 377 * to the ftrace_stub. 378 */ 379 if (rcu_dereference_protected(*list, 380 lockdep_is_held(&ftrace_lock)) == ops && 381 rcu_dereference_protected(ops->next, 382 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) { 383 *list = &ftrace_list_end; 384 return 0; 385 } 386 387 for (p = list; *p != &ftrace_list_end; p = &(*p)->next) 388 if (*p == ops) 389 break; 390 391 if (*p != ops) 392 return -1; 393 394 *p = (*p)->next; 395 return 0; 396 } 397 398 static void ftrace_update_trampoline(struct ftrace_ops *ops); 399 400 static int __register_ftrace_function(struct ftrace_ops *ops) 401 { 402 if (ops->flags & FTRACE_OPS_FL_DELETED) 403 return -EINVAL; 404 405 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED)) 406 return -EBUSY; 407 408 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS 409 /* 410 * If the ftrace_ops specifies SAVE_REGS, then it only can be used 411 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set. 412 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant. 413 */ 414 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS && 415 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)) 416 return -EINVAL; 417 418 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED) 419 ops->flags |= FTRACE_OPS_FL_SAVE_REGS; 420 #endif 421 422 if (!core_kernel_data((unsigned long)ops)) 423 ops->flags |= FTRACE_OPS_FL_DYNAMIC; 424 425 if (ops->flags & FTRACE_OPS_FL_PER_CPU) { 426 if (per_cpu_ops_alloc(ops)) 427 return -ENOMEM; 428 } 429 430 add_ftrace_ops(&ftrace_ops_list, ops); 431 432 /* Always save the function, and reset at unregistering */ 433 ops->saved_func = ops->func; 434 435 if (ftrace_pids_enabled(ops)) 436 ops->func = ftrace_pid_func; 437 438 ftrace_update_trampoline(ops); 439 440 if (ftrace_enabled) 441 update_ftrace_function(); 442 443 return 0; 444 } 445 446 static int __unregister_ftrace_function(struct ftrace_ops *ops) 447 { 448 int ret; 449 450 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED))) 451 return -EBUSY; 452 453 ret = remove_ftrace_ops(&ftrace_ops_list, ops); 454 455 if (ret < 0) 456 return ret; 457 458 if (ftrace_enabled) 459 update_ftrace_function(); 460 461 ops->func = ops->saved_func; 462 463 return 0; 464 } 465 466 static void ftrace_update_pid_func(void) 467 { 468 struct ftrace_ops *op; 469 470 /* Only do something if we are tracing something */ 471 if (ftrace_trace_function == ftrace_stub) 472 return; 473 474 do_for_each_ftrace_op(op, ftrace_ops_list) { 475 if (op->flags & FTRACE_OPS_FL_PID) { 476 op->func = ftrace_pids_enabled(op) ? 477 ftrace_pid_func : op->saved_func; 478 ftrace_update_trampoline(op); 479 } 480 } while_for_each_ftrace_op(op); 481 482 update_ftrace_function(); 483 } 484 485 #ifdef CONFIG_FUNCTION_PROFILER 486 struct ftrace_profile { 487 struct hlist_node node; 488 unsigned long ip; 489 unsigned long counter; 490 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 491 unsigned long long time; 492 unsigned long long time_squared; 493 #endif 494 }; 495 496 struct ftrace_profile_page { 497 struct ftrace_profile_page *next; 498 unsigned long index; 499 struct ftrace_profile records[]; 500 }; 501 502 struct ftrace_profile_stat { 503 atomic_t disabled; 504 struct hlist_head *hash; 505 struct ftrace_profile_page *pages; 506 struct ftrace_profile_page *start; 507 struct tracer_stat stat; 508 }; 509 510 #define PROFILE_RECORDS_SIZE \ 511 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records)) 512 513 #define PROFILES_PER_PAGE \ 514 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile)) 515 516 static int ftrace_profile_enabled __read_mostly; 517 518 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */ 519 static DEFINE_MUTEX(ftrace_profile_lock); 520 521 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats); 522 523 #define FTRACE_PROFILE_HASH_BITS 10 524 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS) 525 526 static void * 527 function_stat_next(void *v, int idx) 528 { 529 struct ftrace_profile *rec = v; 530 struct ftrace_profile_page *pg; 531 532 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK); 533 534 again: 535 if (idx != 0) 536 rec++; 537 538 if ((void *)rec >= (void *)&pg->records[pg->index]) { 539 pg = pg->next; 540 if (!pg) 541 return NULL; 542 rec = &pg->records[0]; 543 if (!rec->counter) 544 goto again; 545 } 546 547 return rec; 548 } 549 550 static void *function_stat_start(struct tracer_stat *trace) 551 { 552 struct ftrace_profile_stat *stat = 553 container_of(trace, struct ftrace_profile_stat, stat); 554 555 if (!stat || !stat->start) 556 return NULL; 557 558 return function_stat_next(&stat->start->records[0], 0); 559 } 560 561 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 562 /* function graph compares on total time */ 563 static int function_stat_cmp(void *p1, void *p2) 564 { 565 struct ftrace_profile *a = p1; 566 struct ftrace_profile *b = p2; 567 568 if (a->time < b->time) 569 return -1; 570 if (a->time > b->time) 571 return 1; 572 else 573 return 0; 574 } 575 #else 576 /* not function graph compares against hits */ 577 static int function_stat_cmp(void *p1, void *p2) 578 { 579 struct ftrace_profile *a = p1; 580 struct ftrace_profile *b = p2; 581 582 if (a->counter < b->counter) 583 return -1; 584 if (a->counter > b->counter) 585 return 1; 586 else 587 return 0; 588 } 589 #endif 590 591 static int function_stat_headers(struct seq_file *m) 592 { 593 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 594 seq_puts(m, " Function " 595 "Hit Time Avg s^2\n" 596 " -------- " 597 "--- ---- --- ---\n"); 598 #else 599 seq_puts(m, " Function Hit\n" 600 " -------- ---\n"); 601 #endif 602 return 0; 603 } 604 605 static int function_stat_show(struct seq_file *m, void *v) 606 { 607 struct ftrace_profile *rec = v; 608 char str[KSYM_SYMBOL_LEN]; 609 int ret = 0; 610 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 611 static struct trace_seq s; 612 unsigned long long avg; 613 unsigned long long stddev; 614 #endif 615 mutex_lock(&ftrace_profile_lock); 616 617 /* we raced with function_profile_reset() */ 618 if (unlikely(rec->counter == 0)) { 619 ret = -EBUSY; 620 goto out; 621 } 622 623 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 624 avg = rec->time; 625 do_div(avg, rec->counter); 626 if (tracing_thresh && (avg < tracing_thresh)) 627 goto out; 628 #endif 629 630 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); 631 seq_printf(m, " %-30.30s %10lu", str, rec->counter); 632 633 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 634 seq_puts(m, " "); 635 636 /* Sample standard deviation (s^2) */ 637 if (rec->counter <= 1) 638 stddev = 0; 639 else { 640 /* 641 * Apply Welford's method: 642 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) 643 */ 644 stddev = rec->counter * rec->time_squared - 645 rec->time * rec->time; 646 647 /* 648 * Divide only 1000 for ns^2 -> us^2 conversion. 649 * trace_print_graph_duration will divide 1000 again. 650 */ 651 do_div(stddev, rec->counter * (rec->counter - 1) * 1000); 652 } 653 654 trace_seq_init(&s); 655 trace_print_graph_duration(rec->time, &s); 656 trace_seq_puts(&s, " "); 657 trace_print_graph_duration(avg, &s); 658 trace_seq_puts(&s, " "); 659 trace_print_graph_duration(stddev, &s); 660 trace_print_seq(m, &s); 661 #endif 662 seq_putc(m, '\n'); 663 out: 664 mutex_unlock(&ftrace_profile_lock); 665 666 return ret; 667 } 668 669 static void ftrace_profile_reset(struct ftrace_profile_stat *stat) 670 { 671 struct ftrace_profile_page *pg; 672 673 pg = stat->pages = stat->start; 674 675 while (pg) { 676 memset(pg->records, 0, PROFILE_RECORDS_SIZE); 677 pg->index = 0; 678 pg = pg->next; 679 } 680 681 memset(stat->hash, 0, 682 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head)); 683 } 684 685 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat) 686 { 687 struct ftrace_profile_page *pg; 688 int functions; 689 int pages; 690 int i; 691 692 /* If we already allocated, do nothing */ 693 if (stat->pages) 694 return 0; 695 696 stat->pages = (void *)get_zeroed_page(GFP_KERNEL); 697 if (!stat->pages) 698 return -ENOMEM; 699 700 #ifdef CONFIG_DYNAMIC_FTRACE 701 functions = ftrace_update_tot_cnt; 702 #else 703 /* 704 * We do not know the number of functions that exist because 705 * dynamic tracing is what counts them. With past experience 706 * we have around 20K functions. That should be more than enough. 707 * It is highly unlikely we will execute every function in 708 * the kernel. 709 */ 710 functions = 20000; 711 #endif 712 713 pg = stat->start = stat->pages; 714 715 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE); 716 717 for (i = 1; i < pages; i++) { 718 pg->next = (void *)get_zeroed_page(GFP_KERNEL); 719 if (!pg->next) 720 goto out_free; 721 pg = pg->next; 722 } 723 724 return 0; 725 726 out_free: 727 pg = stat->start; 728 while (pg) { 729 unsigned long tmp = (unsigned long)pg; 730 731 pg = pg->next; 732 free_page(tmp); 733 } 734 735 stat->pages = NULL; 736 stat->start = NULL; 737 738 return -ENOMEM; 739 } 740 741 static int ftrace_profile_init_cpu(int cpu) 742 { 743 struct ftrace_profile_stat *stat; 744 int size; 745 746 stat = &per_cpu(ftrace_profile_stats, cpu); 747 748 if (stat->hash) { 749 /* If the profile is already created, simply reset it */ 750 ftrace_profile_reset(stat); 751 return 0; 752 } 753 754 /* 755 * We are profiling all functions, but usually only a few thousand 756 * functions are hit. We'll make a hash of 1024 items. 757 */ 758 size = FTRACE_PROFILE_HASH_SIZE; 759 760 stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL); 761 762 if (!stat->hash) 763 return -ENOMEM; 764 765 /* Preallocate the function profiling pages */ 766 if (ftrace_profile_pages_init(stat) < 0) { 767 kfree(stat->hash); 768 stat->hash = NULL; 769 return -ENOMEM; 770 } 771 772 return 0; 773 } 774 775 static int ftrace_profile_init(void) 776 { 777 int cpu; 778 int ret = 0; 779 780 for_each_possible_cpu(cpu) { 781 ret = ftrace_profile_init_cpu(cpu); 782 if (ret) 783 break; 784 } 785 786 return ret; 787 } 788 789 /* interrupts must be disabled */ 790 static struct ftrace_profile * 791 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip) 792 { 793 struct ftrace_profile *rec; 794 struct hlist_head *hhd; 795 unsigned long key; 796 797 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS); 798 hhd = &stat->hash[key]; 799 800 if (hlist_empty(hhd)) 801 return NULL; 802 803 hlist_for_each_entry_rcu_notrace(rec, hhd, node) { 804 if (rec->ip == ip) 805 return rec; 806 } 807 808 return NULL; 809 } 810 811 static void ftrace_add_profile(struct ftrace_profile_stat *stat, 812 struct ftrace_profile *rec) 813 { 814 unsigned long key; 815 816 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS); 817 hlist_add_head_rcu(&rec->node, &stat->hash[key]); 818 } 819 820 /* 821 * The memory is already allocated, this simply finds a new record to use. 822 */ 823 static struct ftrace_profile * 824 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip) 825 { 826 struct ftrace_profile *rec = NULL; 827 828 /* prevent recursion (from NMIs) */ 829 if (atomic_inc_return(&stat->disabled) != 1) 830 goto out; 831 832 /* 833 * Try to find the function again since an NMI 834 * could have added it 835 */ 836 rec = ftrace_find_profiled_func(stat, ip); 837 if (rec) 838 goto out; 839 840 if (stat->pages->index == PROFILES_PER_PAGE) { 841 if (!stat->pages->next) 842 goto out; 843 stat->pages = stat->pages->next; 844 } 845 846 rec = &stat->pages->records[stat->pages->index++]; 847 rec->ip = ip; 848 ftrace_add_profile(stat, rec); 849 850 out: 851 atomic_dec(&stat->disabled); 852 853 return rec; 854 } 855 856 static void 857 function_profile_call(unsigned long ip, unsigned long parent_ip, 858 struct ftrace_ops *ops, struct pt_regs *regs) 859 { 860 struct ftrace_profile_stat *stat; 861 struct ftrace_profile *rec; 862 unsigned long flags; 863 864 if (!ftrace_profile_enabled) 865 return; 866 867 local_irq_save(flags); 868 869 stat = this_cpu_ptr(&ftrace_profile_stats); 870 if (!stat->hash || !ftrace_profile_enabled) 871 goto out; 872 873 rec = ftrace_find_profiled_func(stat, ip); 874 if (!rec) { 875 rec = ftrace_profile_alloc(stat, ip); 876 if (!rec) 877 goto out; 878 } 879 880 rec->counter++; 881 out: 882 local_irq_restore(flags); 883 } 884 885 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 886 static int profile_graph_entry(struct ftrace_graph_ent *trace) 887 { 888 int index = trace->depth; 889 890 function_profile_call(trace->func, 0, NULL, NULL); 891 892 /* If function graph is shutting down, ret_stack can be NULL */ 893 if (!current->ret_stack) 894 return 0; 895 896 if (index >= 0 && index < FTRACE_RETFUNC_DEPTH) 897 current->ret_stack[index].subtime = 0; 898 899 return 1; 900 } 901 902 static void profile_graph_return(struct ftrace_graph_ret *trace) 903 { 904 struct ftrace_profile_stat *stat; 905 unsigned long long calltime; 906 struct ftrace_profile *rec; 907 unsigned long flags; 908 909 local_irq_save(flags); 910 stat = this_cpu_ptr(&ftrace_profile_stats); 911 if (!stat->hash || !ftrace_profile_enabled) 912 goto out; 913 914 /* If the calltime was zero'd ignore it */ 915 if (!trace->calltime) 916 goto out; 917 918 calltime = trace->rettime - trace->calltime; 919 920 if (!fgraph_graph_time) { 921 int index; 922 923 index = trace->depth; 924 925 /* Append this call time to the parent time to subtract */ 926 if (index) 927 current->ret_stack[index - 1].subtime += calltime; 928 929 if (current->ret_stack[index].subtime < calltime) 930 calltime -= current->ret_stack[index].subtime; 931 else 932 calltime = 0; 933 } 934 935 rec = ftrace_find_profiled_func(stat, trace->func); 936 if (rec) { 937 rec->time += calltime; 938 rec->time_squared += calltime * calltime; 939 } 940 941 out: 942 local_irq_restore(flags); 943 } 944 945 static int register_ftrace_profiler(void) 946 { 947 return register_ftrace_graph(&profile_graph_return, 948 &profile_graph_entry); 949 } 950 951 static void unregister_ftrace_profiler(void) 952 { 953 unregister_ftrace_graph(); 954 } 955 #else 956 static struct ftrace_ops ftrace_profile_ops __read_mostly = { 957 .func = function_profile_call, 958 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED, 959 INIT_OPS_HASH(ftrace_profile_ops) 960 }; 961 962 static int register_ftrace_profiler(void) 963 { 964 return register_ftrace_function(&ftrace_profile_ops); 965 } 966 967 static void unregister_ftrace_profiler(void) 968 { 969 unregister_ftrace_function(&ftrace_profile_ops); 970 } 971 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 972 973 static ssize_t 974 ftrace_profile_write(struct file *filp, const char __user *ubuf, 975 size_t cnt, loff_t *ppos) 976 { 977 unsigned long val; 978 int ret; 979 980 ret = kstrtoul_from_user(ubuf, cnt, 10, &val); 981 if (ret) 982 return ret; 983 984 val = !!val; 985 986 mutex_lock(&ftrace_profile_lock); 987 if (ftrace_profile_enabled ^ val) { 988 if (val) { 989 ret = ftrace_profile_init(); 990 if (ret < 0) { 991 cnt = ret; 992 goto out; 993 } 994 995 ret = register_ftrace_profiler(); 996 if (ret < 0) { 997 cnt = ret; 998 goto out; 999 } 1000 ftrace_profile_enabled = 1; 1001 } else { 1002 ftrace_profile_enabled = 0; 1003 /* 1004 * unregister_ftrace_profiler calls stop_machine 1005 * so this acts like an synchronize_sched. 1006 */ 1007 unregister_ftrace_profiler(); 1008 } 1009 } 1010 out: 1011 mutex_unlock(&ftrace_profile_lock); 1012 1013 *ppos += cnt; 1014 1015 return cnt; 1016 } 1017 1018 static ssize_t 1019 ftrace_profile_read(struct file *filp, char __user *ubuf, 1020 size_t cnt, loff_t *ppos) 1021 { 1022 char buf[64]; /* big enough to hold a number */ 1023 int r; 1024 1025 r = sprintf(buf, "%u\n", ftrace_profile_enabled); 1026 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); 1027 } 1028 1029 static const struct file_operations ftrace_profile_fops = { 1030 .open = tracing_open_generic, 1031 .read = ftrace_profile_read, 1032 .write = ftrace_profile_write, 1033 .llseek = default_llseek, 1034 }; 1035 1036 /* used to initialize the real stat files */ 1037 static struct tracer_stat function_stats __initdata = { 1038 .name = "functions", 1039 .stat_start = function_stat_start, 1040 .stat_next = function_stat_next, 1041 .stat_cmp = function_stat_cmp, 1042 .stat_headers = function_stat_headers, 1043 .stat_show = function_stat_show 1044 }; 1045 1046 static __init void ftrace_profile_tracefs(struct dentry *d_tracer) 1047 { 1048 struct ftrace_profile_stat *stat; 1049 struct dentry *entry; 1050 char *name; 1051 int ret; 1052 int cpu; 1053 1054 for_each_possible_cpu(cpu) { 1055 stat = &per_cpu(ftrace_profile_stats, cpu); 1056 1057 name = kasprintf(GFP_KERNEL, "function%d", cpu); 1058 if (!name) { 1059 /* 1060 * The files created are permanent, if something happens 1061 * we still do not free memory. 1062 */ 1063 WARN(1, 1064 "Could not allocate stat file for cpu %d\n", 1065 cpu); 1066 return; 1067 } 1068 stat->stat = function_stats; 1069 stat->stat.name = name; 1070 ret = register_stat_tracer(&stat->stat); 1071 if (ret) { 1072 WARN(1, 1073 "Could not register function stat for cpu %d\n", 1074 cpu); 1075 kfree(name); 1076 return; 1077 } 1078 } 1079 1080 entry = tracefs_create_file("function_profile_enabled", 0644, 1081 d_tracer, NULL, &ftrace_profile_fops); 1082 if (!entry) 1083 pr_warn("Could not create tracefs 'function_profile_enabled' entry\n"); 1084 } 1085 1086 #else /* CONFIG_FUNCTION_PROFILER */ 1087 static __init void ftrace_profile_tracefs(struct dentry *d_tracer) 1088 { 1089 } 1090 #endif /* CONFIG_FUNCTION_PROFILER */ 1091 1092 static struct pid * const ftrace_swapper_pid = &init_struct_pid; 1093 1094 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 1095 static int ftrace_graph_active; 1096 #else 1097 # define ftrace_graph_active 0 1098 #endif 1099 1100 #ifdef CONFIG_DYNAMIC_FTRACE 1101 1102 static struct ftrace_ops *removed_ops; 1103 1104 /* 1105 * Set when doing a global update, like enabling all recs or disabling them. 1106 * It is not set when just updating a single ftrace_ops. 1107 */ 1108 static bool update_all_ops; 1109 1110 #ifndef CONFIG_FTRACE_MCOUNT_RECORD 1111 # error Dynamic ftrace depends on MCOUNT_RECORD 1112 #endif 1113 1114 struct ftrace_func_entry { 1115 struct hlist_node hlist; 1116 unsigned long ip; 1117 }; 1118 1119 struct ftrace_func_probe { 1120 struct ftrace_probe_ops *probe_ops; 1121 struct ftrace_ops ops; 1122 struct trace_array *tr; 1123 struct list_head list; 1124 void *data; 1125 int ref; 1126 }; 1127 1128 /* 1129 * We make these constant because no one should touch them, 1130 * but they are used as the default "empty hash", to avoid allocating 1131 * it all the time. These are in a read only section such that if 1132 * anyone does try to modify it, it will cause an exception. 1133 */ 1134 static const struct hlist_head empty_buckets[1]; 1135 static const struct ftrace_hash empty_hash = { 1136 .buckets = (struct hlist_head *)empty_buckets, 1137 }; 1138 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash) 1139 1140 static struct ftrace_ops global_ops = { 1141 .func = ftrace_stub, 1142 .local_hash.notrace_hash = EMPTY_HASH, 1143 .local_hash.filter_hash = EMPTY_HASH, 1144 INIT_OPS_HASH(global_ops) 1145 .flags = FTRACE_OPS_FL_RECURSION_SAFE | 1146 FTRACE_OPS_FL_INITIALIZED | 1147 FTRACE_OPS_FL_PID, 1148 }; 1149 1150 /* 1151 * This is used by __kernel_text_address() to return true if the 1152 * address is on a dynamically allocated trampoline that would 1153 * not return true for either core_kernel_text() or 1154 * is_module_text_address(). 1155 */ 1156 bool is_ftrace_trampoline(unsigned long addr) 1157 { 1158 struct ftrace_ops *op; 1159 bool ret = false; 1160 1161 /* 1162 * Some of the ops may be dynamically allocated, 1163 * they are freed after a synchronize_sched(). 1164 */ 1165 preempt_disable_notrace(); 1166 1167 do_for_each_ftrace_op(op, ftrace_ops_list) { 1168 /* 1169 * This is to check for dynamically allocated trampolines. 1170 * Trampolines that are in kernel text will have 1171 * core_kernel_text() return true. 1172 */ 1173 if (op->trampoline && op->trampoline_size) 1174 if (addr >= op->trampoline && 1175 addr < op->trampoline + op->trampoline_size) { 1176 ret = true; 1177 goto out; 1178 } 1179 } while_for_each_ftrace_op(op); 1180 1181 out: 1182 preempt_enable_notrace(); 1183 1184 return ret; 1185 } 1186 1187 struct ftrace_page { 1188 struct ftrace_page *next; 1189 struct dyn_ftrace *records; 1190 int index; 1191 int size; 1192 }; 1193 1194 #define ENTRY_SIZE sizeof(struct dyn_ftrace) 1195 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE) 1196 1197 /* estimate from running different kernels */ 1198 #define NR_TO_INIT 10000 1199 1200 static struct ftrace_page *ftrace_pages_start; 1201 static struct ftrace_page *ftrace_pages; 1202 1203 static __always_inline unsigned long 1204 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip) 1205 { 1206 if (hash->size_bits > 0) 1207 return hash_long(ip, hash->size_bits); 1208 1209 return 0; 1210 } 1211 1212 /* Only use this function if ftrace_hash_empty() has already been tested */ 1213 static __always_inline struct ftrace_func_entry * 1214 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip) 1215 { 1216 unsigned long key; 1217 struct ftrace_func_entry *entry; 1218 struct hlist_head *hhd; 1219 1220 key = ftrace_hash_key(hash, ip); 1221 hhd = &hash->buckets[key]; 1222 1223 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) { 1224 if (entry->ip == ip) 1225 return entry; 1226 } 1227 return NULL; 1228 } 1229 1230 /** 1231 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash 1232 * @hash: The hash to look at 1233 * @ip: The instruction pointer to test 1234 * 1235 * Search a given @hash to see if a given instruction pointer (@ip) 1236 * exists in it. 1237 * 1238 * Returns the entry that holds the @ip if found. NULL otherwise. 1239 */ 1240 struct ftrace_func_entry * 1241 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip) 1242 { 1243 if (ftrace_hash_empty(hash)) 1244 return NULL; 1245 1246 return __ftrace_lookup_ip(hash, ip); 1247 } 1248 1249 static void __add_hash_entry(struct ftrace_hash *hash, 1250 struct ftrace_func_entry *entry) 1251 { 1252 struct hlist_head *hhd; 1253 unsigned long key; 1254 1255 key = ftrace_hash_key(hash, entry->ip); 1256 hhd = &hash->buckets[key]; 1257 hlist_add_head(&entry->hlist, hhd); 1258 hash->count++; 1259 } 1260 1261 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip) 1262 { 1263 struct ftrace_func_entry *entry; 1264 1265 entry = kmalloc(sizeof(*entry), GFP_KERNEL); 1266 if (!entry) 1267 return -ENOMEM; 1268 1269 entry->ip = ip; 1270 __add_hash_entry(hash, entry); 1271 1272 return 0; 1273 } 1274 1275 static void 1276 free_hash_entry(struct ftrace_hash *hash, 1277 struct ftrace_func_entry *entry) 1278 { 1279 hlist_del(&entry->hlist); 1280 kfree(entry); 1281 hash->count--; 1282 } 1283 1284 static void 1285 remove_hash_entry(struct ftrace_hash *hash, 1286 struct ftrace_func_entry *entry) 1287 { 1288 hlist_del_rcu(&entry->hlist); 1289 hash->count--; 1290 } 1291 1292 static void ftrace_hash_clear(struct ftrace_hash *hash) 1293 { 1294 struct hlist_head *hhd; 1295 struct hlist_node *tn; 1296 struct ftrace_func_entry *entry; 1297 int size = 1 << hash->size_bits; 1298 int i; 1299 1300 if (!hash->count) 1301 return; 1302 1303 for (i = 0; i < size; i++) { 1304 hhd = &hash->buckets[i]; 1305 hlist_for_each_entry_safe(entry, tn, hhd, hlist) 1306 free_hash_entry(hash, entry); 1307 } 1308 FTRACE_WARN_ON(hash->count); 1309 } 1310 1311 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod) 1312 { 1313 list_del(&ftrace_mod->list); 1314 kfree(ftrace_mod->module); 1315 kfree(ftrace_mod->func); 1316 kfree(ftrace_mod); 1317 } 1318 1319 static void clear_ftrace_mod_list(struct list_head *head) 1320 { 1321 struct ftrace_mod_load *p, *n; 1322 1323 /* stack tracer isn't supported yet */ 1324 if (!head) 1325 return; 1326 1327 mutex_lock(&ftrace_lock); 1328 list_for_each_entry_safe(p, n, head, list) 1329 free_ftrace_mod(p); 1330 mutex_unlock(&ftrace_lock); 1331 } 1332 1333 static void free_ftrace_hash(struct ftrace_hash *hash) 1334 { 1335 if (!hash || hash == EMPTY_HASH) 1336 return; 1337 ftrace_hash_clear(hash); 1338 kfree(hash->buckets); 1339 kfree(hash); 1340 } 1341 1342 static void __free_ftrace_hash_rcu(struct rcu_head *rcu) 1343 { 1344 struct ftrace_hash *hash; 1345 1346 hash = container_of(rcu, struct ftrace_hash, rcu); 1347 free_ftrace_hash(hash); 1348 } 1349 1350 static void free_ftrace_hash_rcu(struct ftrace_hash *hash) 1351 { 1352 if (!hash || hash == EMPTY_HASH) 1353 return; 1354 call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu); 1355 } 1356 1357 void ftrace_free_filter(struct ftrace_ops *ops) 1358 { 1359 ftrace_ops_init(ops); 1360 free_ftrace_hash(ops->func_hash->filter_hash); 1361 free_ftrace_hash(ops->func_hash->notrace_hash); 1362 } 1363 1364 static struct ftrace_hash *alloc_ftrace_hash(int size_bits) 1365 { 1366 struct ftrace_hash *hash; 1367 int size; 1368 1369 hash = kzalloc(sizeof(*hash), GFP_KERNEL); 1370 if (!hash) 1371 return NULL; 1372 1373 size = 1 << size_bits; 1374 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL); 1375 1376 if (!hash->buckets) { 1377 kfree(hash); 1378 return NULL; 1379 } 1380 1381 hash->size_bits = size_bits; 1382 1383 return hash; 1384 } 1385 1386 1387 static int ftrace_add_mod(struct trace_array *tr, 1388 const char *func, const char *module, 1389 int enable) 1390 { 1391 struct ftrace_mod_load *ftrace_mod; 1392 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace; 1393 1394 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL); 1395 if (!ftrace_mod) 1396 return -ENOMEM; 1397 1398 ftrace_mod->func = kstrdup(func, GFP_KERNEL); 1399 ftrace_mod->module = kstrdup(module, GFP_KERNEL); 1400 ftrace_mod->enable = enable; 1401 1402 if (!ftrace_mod->func || !ftrace_mod->module) 1403 goto out_free; 1404 1405 list_add(&ftrace_mod->list, mod_head); 1406 1407 return 0; 1408 1409 out_free: 1410 free_ftrace_mod(ftrace_mod); 1411 1412 return -ENOMEM; 1413 } 1414 1415 static struct ftrace_hash * 1416 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash) 1417 { 1418 struct ftrace_func_entry *entry; 1419 struct ftrace_hash *new_hash; 1420 int size; 1421 int ret; 1422 int i; 1423 1424 new_hash = alloc_ftrace_hash(size_bits); 1425 if (!new_hash) 1426 return NULL; 1427 1428 if (hash) 1429 new_hash->flags = hash->flags; 1430 1431 /* Empty hash? */ 1432 if (ftrace_hash_empty(hash)) 1433 return new_hash; 1434 1435 size = 1 << hash->size_bits; 1436 for (i = 0; i < size; i++) { 1437 hlist_for_each_entry(entry, &hash->buckets[i], hlist) { 1438 ret = add_hash_entry(new_hash, entry->ip); 1439 if (ret < 0) 1440 goto free_hash; 1441 } 1442 } 1443 1444 FTRACE_WARN_ON(new_hash->count != hash->count); 1445 1446 return new_hash; 1447 1448 free_hash: 1449 free_ftrace_hash(new_hash); 1450 return NULL; 1451 } 1452 1453 static void 1454 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash); 1455 static void 1456 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash); 1457 1458 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops, 1459 struct ftrace_hash *new_hash); 1460 1461 static struct ftrace_hash * 1462 __ftrace_hash_move(struct ftrace_hash *src) 1463 { 1464 struct ftrace_func_entry *entry; 1465 struct hlist_node *tn; 1466 struct hlist_head *hhd; 1467 struct ftrace_hash *new_hash; 1468 int size = src->count; 1469 int bits = 0; 1470 int i; 1471 1472 /* 1473 * If the new source is empty, just return the empty_hash. 1474 */ 1475 if (ftrace_hash_empty(src)) 1476 return EMPTY_HASH; 1477 1478 /* 1479 * Make the hash size about 1/2 the # found 1480 */ 1481 for (size /= 2; size; size >>= 1) 1482 bits++; 1483 1484 /* Don't allocate too much */ 1485 if (bits > FTRACE_HASH_MAX_BITS) 1486 bits = FTRACE_HASH_MAX_BITS; 1487 1488 new_hash = alloc_ftrace_hash(bits); 1489 if (!new_hash) 1490 return NULL; 1491 1492 new_hash->flags = src->flags; 1493 1494 size = 1 << src->size_bits; 1495 for (i = 0; i < size; i++) { 1496 hhd = &src->buckets[i]; 1497 hlist_for_each_entry_safe(entry, tn, hhd, hlist) { 1498 remove_hash_entry(src, entry); 1499 __add_hash_entry(new_hash, entry); 1500 } 1501 } 1502 1503 return new_hash; 1504 } 1505 1506 static int 1507 ftrace_hash_move(struct ftrace_ops *ops, int enable, 1508 struct ftrace_hash **dst, struct ftrace_hash *src) 1509 { 1510 struct ftrace_hash *new_hash; 1511 int ret; 1512 1513 /* Reject setting notrace hash on IPMODIFY ftrace_ops */ 1514 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable) 1515 return -EINVAL; 1516 1517 new_hash = __ftrace_hash_move(src); 1518 if (!new_hash) 1519 return -ENOMEM; 1520 1521 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */ 1522 if (enable) { 1523 /* IPMODIFY should be updated only when filter_hash updating */ 1524 ret = ftrace_hash_ipmodify_update(ops, new_hash); 1525 if (ret < 0) { 1526 free_ftrace_hash(new_hash); 1527 return ret; 1528 } 1529 } 1530 1531 /* 1532 * Remove the current set, update the hash and add 1533 * them back. 1534 */ 1535 ftrace_hash_rec_disable_modify(ops, enable); 1536 1537 rcu_assign_pointer(*dst, new_hash); 1538 1539 ftrace_hash_rec_enable_modify(ops, enable); 1540 1541 return 0; 1542 } 1543 1544 static bool hash_contains_ip(unsigned long ip, 1545 struct ftrace_ops_hash *hash) 1546 { 1547 /* 1548 * The function record is a match if it exists in the filter 1549 * hash and not in the notrace hash. Note, an emty hash is 1550 * considered a match for the filter hash, but an empty 1551 * notrace hash is considered not in the notrace hash. 1552 */ 1553 return (ftrace_hash_empty(hash->filter_hash) || 1554 __ftrace_lookup_ip(hash->filter_hash, ip)) && 1555 (ftrace_hash_empty(hash->notrace_hash) || 1556 !__ftrace_lookup_ip(hash->notrace_hash, ip)); 1557 } 1558 1559 /* 1560 * Test the hashes for this ops to see if we want to call 1561 * the ops->func or not. 1562 * 1563 * It's a match if the ip is in the ops->filter_hash or 1564 * the filter_hash does not exist or is empty, 1565 * AND 1566 * the ip is not in the ops->notrace_hash. 1567 * 1568 * This needs to be called with preemption disabled as 1569 * the hashes are freed with call_rcu_sched(). 1570 */ 1571 static int 1572 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) 1573 { 1574 struct ftrace_ops_hash hash; 1575 int ret; 1576 1577 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 1578 /* 1579 * There's a small race when adding ops that the ftrace handler 1580 * that wants regs, may be called without them. We can not 1581 * allow that handler to be called if regs is NULL. 1582 */ 1583 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS)) 1584 return 0; 1585 #endif 1586 1587 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash); 1588 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash); 1589 1590 if (hash_contains_ip(ip, &hash)) 1591 ret = 1; 1592 else 1593 ret = 0; 1594 1595 return ret; 1596 } 1597 1598 /* 1599 * This is a double for. Do not use 'break' to break out of the loop, 1600 * you must use a goto. 1601 */ 1602 #define do_for_each_ftrace_rec(pg, rec) \ 1603 for (pg = ftrace_pages_start; pg; pg = pg->next) { \ 1604 int _____i; \ 1605 for (_____i = 0; _____i < pg->index; _____i++) { \ 1606 rec = &pg->records[_____i]; 1607 1608 #define while_for_each_ftrace_rec() \ 1609 } \ 1610 } 1611 1612 1613 static int ftrace_cmp_recs(const void *a, const void *b) 1614 { 1615 const struct dyn_ftrace *key = a; 1616 const struct dyn_ftrace *rec = b; 1617 1618 if (key->flags < rec->ip) 1619 return -1; 1620 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE) 1621 return 1; 1622 return 0; 1623 } 1624 1625 /** 1626 * ftrace_location_range - return the first address of a traced location 1627 * if it touches the given ip range 1628 * @start: start of range to search. 1629 * @end: end of range to search (inclusive). @end points to the last byte 1630 * to check. 1631 * 1632 * Returns rec->ip if the related ftrace location is a least partly within 1633 * the given address range. That is, the first address of the instruction 1634 * that is either a NOP or call to the function tracer. It checks the ftrace 1635 * internal tables to determine if the address belongs or not. 1636 */ 1637 unsigned long ftrace_location_range(unsigned long start, unsigned long end) 1638 { 1639 struct ftrace_page *pg; 1640 struct dyn_ftrace *rec; 1641 struct dyn_ftrace key; 1642 1643 key.ip = start; 1644 key.flags = end; /* overload flags, as it is unsigned long */ 1645 1646 for (pg = ftrace_pages_start; pg; pg = pg->next) { 1647 if (end < pg->records[0].ip || 1648 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE)) 1649 continue; 1650 rec = bsearch(&key, pg->records, pg->index, 1651 sizeof(struct dyn_ftrace), 1652 ftrace_cmp_recs); 1653 if (rec) 1654 return rec->ip; 1655 } 1656 1657 return 0; 1658 } 1659 1660 /** 1661 * ftrace_location - return true if the ip giving is a traced location 1662 * @ip: the instruction pointer to check 1663 * 1664 * Returns rec->ip if @ip given is a pointer to a ftrace location. 1665 * That is, the instruction that is either a NOP or call to 1666 * the function tracer. It checks the ftrace internal tables to 1667 * determine if the address belongs or not. 1668 */ 1669 unsigned long ftrace_location(unsigned long ip) 1670 { 1671 return ftrace_location_range(ip, ip); 1672 } 1673 1674 /** 1675 * ftrace_text_reserved - return true if range contains an ftrace location 1676 * @start: start of range to search 1677 * @end: end of range to search (inclusive). @end points to the last byte to check. 1678 * 1679 * Returns 1 if @start and @end contains a ftrace location. 1680 * That is, the instruction that is either a NOP or call to 1681 * the function tracer. It checks the ftrace internal tables to 1682 * determine if the address belongs or not. 1683 */ 1684 int ftrace_text_reserved(const void *start, const void *end) 1685 { 1686 unsigned long ret; 1687 1688 ret = ftrace_location_range((unsigned long)start, 1689 (unsigned long)end); 1690 1691 return (int)!!ret; 1692 } 1693 1694 /* Test if ops registered to this rec needs regs */ 1695 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec) 1696 { 1697 struct ftrace_ops *ops; 1698 bool keep_regs = false; 1699 1700 for (ops = ftrace_ops_list; 1701 ops != &ftrace_list_end; ops = ops->next) { 1702 /* pass rec in as regs to have non-NULL val */ 1703 if (ftrace_ops_test(ops, rec->ip, rec)) { 1704 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) { 1705 keep_regs = true; 1706 break; 1707 } 1708 } 1709 } 1710 1711 return keep_regs; 1712 } 1713 1714 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops, 1715 int filter_hash, 1716 bool inc) 1717 { 1718 struct ftrace_hash *hash; 1719 struct ftrace_hash *other_hash; 1720 struct ftrace_page *pg; 1721 struct dyn_ftrace *rec; 1722 bool update = false; 1723 int count = 0; 1724 int all = false; 1725 1726 /* Only update if the ops has been registered */ 1727 if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) 1728 return false; 1729 1730 /* 1731 * In the filter_hash case: 1732 * If the count is zero, we update all records. 1733 * Otherwise we just update the items in the hash. 1734 * 1735 * In the notrace_hash case: 1736 * We enable the update in the hash. 1737 * As disabling notrace means enabling the tracing, 1738 * and enabling notrace means disabling, the inc variable 1739 * gets inversed. 1740 */ 1741 if (filter_hash) { 1742 hash = ops->func_hash->filter_hash; 1743 other_hash = ops->func_hash->notrace_hash; 1744 if (ftrace_hash_empty(hash)) 1745 all = true; 1746 } else { 1747 inc = !inc; 1748 hash = ops->func_hash->notrace_hash; 1749 other_hash = ops->func_hash->filter_hash; 1750 /* 1751 * If the notrace hash has no items, 1752 * then there's nothing to do. 1753 */ 1754 if (ftrace_hash_empty(hash)) 1755 return false; 1756 } 1757 1758 do_for_each_ftrace_rec(pg, rec) { 1759 int in_other_hash = 0; 1760 int in_hash = 0; 1761 int match = 0; 1762 1763 if (rec->flags & FTRACE_FL_DISABLED) 1764 continue; 1765 1766 if (all) { 1767 /* 1768 * Only the filter_hash affects all records. 1769 * Update if the record is not in the notrace hash. 1770 */ 1771 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip)) 1772 match = 1; 1773 } else { 1774 in_hash = !!ftrace_lookup_ip(hash, rec->ip); 1775 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip); 1776 1777 /* 1778 * If filter_hash is set, we want to match all functions 1779 * that are in the hash but not in the other hash. 1780 * 1781 * If filter_hash is not set, then we are decrementing. 1782 * That means we match anything that is in the hash 1783 * and also in the other_hash. That is, we need to turn 1784 * off functions in the other hash because they are disabled 1785 * by this hash. 1786 */ 1787 if (filter_hash && in_hash && !in_other_hash) 1788 match = 1; 1789 else if (!filter_hash && in_hash && 1790 (in_other_hash || ftrace_hash_empty(other_hash))) 1791 match = 1; 1792 } 1793 if (!match) 1794 continue; 1795 1796 if (inc) { 1797 rec->flags++; 1798 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX)) 1799 return false; 1800 1801 /* 1802 * If there's only a single callback registered to a 1803 * function, and the ops has a trampoline registered 1804 * for it, then we can call it directly. 1805 */ 1806 if (ftrace_rec_count(rec) == 1 && ops->trampoline) 1807 rec->flags |= FTRACE_FL_TRAMP; 1808 else 1809 /* 1810 * If we are adding another function callback 1811 * to this function, and the previous had a 1812 * custom trampoline in use, then we need to go 1813 * back to the default trampoline. 1814 */ 1815 rec->flags &= ~FTRACE_FL_TRAMP; 1816 1817 /* 1818 * If any ops wants regs saved for this function 1819 * then all ops will get saved regs. 1820 */ 1821 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) 1822 rec->flags |= FTRACE_FL_REGS; 1823 } else { 1824 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0)) 1825 return false; 1826 rec->flags--; 1827 1828 /* 1829 * If the rec had REGS enabled and the ops that is 1830 * being removed had REGS set, then see if there is 1831 * still any ops for this record that wants regs. 1832 * If not, we can stop recording them. 1833 */ 1834 if (ftrace_rec_count(rec) > 0 && 1835 rec->flags & FTRACE_FL_REGS && 1836 ops->flags & FTRACE_OPS_FL_SAVE_REGS) { 1837 if (!test_rec_ops_needs_regs(rec)) 1838 rec->flags &= ~FTRACE_FL_REGS; 1839 } 1840 1841 /* 1842 * If the rec had TRAMP enabled, then it needs to 1843 * be cleared. As TRAMP can only be enabled iff 1844 * there is only a single ops attached to it. 1845 * In otherwords, always disable it on decrementing. 1846 * In the future, we may set it if rec count is 1847 * decremented to one, and the ops that is left 1848 * has a trampoline. 1849 */ 1850 rec->flags &= ~FTRACE_FL_TRAMP; 1851 1852 /* 1853 * flags will be cleared in ftrace_check_record() 1854 * if rec count is zero. 1855 */ 1856 } 1857 count++; 1858 1859 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */ 1860 update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE; 1861 1862 /* Shortcut, if we handled all records, we are done. */ 1863 if (!all && count == hash->count) 1864 return update; 1865 } while_for_each_ftrace_rec(); 1866 1867 return update; 1868 } 1869 1870 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops, 1871 int filter_hash) 1872 { 1873 return __ftrace_hash_rec_update(ops, filter_hash, 0); 1874 } 1875 1876 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops, 1877 int filter_hash) 1878 { 1879 return __ftrace_hash_rec_update(ops, filter_hash, 1); 1880 } 1881 1882 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops, 1883 int filter_hash, int inc) 1884 { 1885 struct ftrace_ops *op; 1886 1887 __ftrace_hash_rec_update(ops, filter_hash, inc); 1888 1889 if (ops->func_hash != &global_ops.local_hash) 1890 return; 1891 1892 /* 1893 * If the ops shares the global_ops hash, then we need to update 1894 * all ops that are enabled and use this hash. 1895 */ 1896 do_for_each_ftrace_op(op, ftrace_ops_list) { 1897 /* Already done */ 1898 if (op == ops) 1899 continue; 1900 if (op->func_hash == &global_ops.local_hash) 1901 __ftrace_hash_rec_update(op, filter_hash, inc); 1902 } while_for_each_ftrace_op(op); 1903 } 1904 1905 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, 1906 int filter_hash) 1907 { 1908 ftrace_hash_rec_update_modify(ops, filter_hash, 0); 1909 } 1910 1911 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, 1912 int filter_hash) 1913 { 1914 ftrace_hash_rec_update_modify(ops, filter_hash, 1); 1915 } 1916 1917 /* 1918 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK 1919 * or no-needed to update, -EBUSY if it detects a conflict of the flag 1920 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs. 1921 * Note that old_hash and new_hash has below meanings 1922 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected) 1923 * - If the hash is EMPTY_HASH, it hits nothing 1924 * - Anything else hits the recs which match the hash entries. 1925 */ 1926 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops, 1927 struct ftrace_hash *old_hash, 1928 struct ftrace_hash *new_hash) 1929 { 1930 struct ftrace_page *pg; 1931 struct dyn_ftrace *rec, *end = NULL; 1932 int in_old, in_new; 1933 1934 /* Only update if the ops has been registered */ 1935 if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) 1936 return 0; 1937 1938 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY)) 1939 return 0; 1940 1941 /* 1942 * Since the IPMODIFY is a very address sensitive action, we do not 1943 * allow ftrace_ops to set all functions to new hash. 1944 */ 1945 if (!new_hash || !old_hash) 1946 return -EINVAL; 1947 1948 /* Update rec->flags */ 1949 do_for_each_ftrace_rec(pg, rec) { 1950 1951 if (rec->flags & FTRACE_FL_DISABLED) 1952 continue; 1953 1954 /* We need to update only differences of filter_hash */ 1955 in_old = !!ftrace_lookup_ip(old_hash, rec->ip); 1956 in_new = !!ftrace_lookup_ip(new_hash, rec->ip); 1957 if (in_old == in_new) 1958 continue; 1959 1960 if (in_new) { 1961 /* New entries must ensure no others are using it */ 1962 if (rec->flags & FTRACE_FL_IPMODIFY) 1963 goto rollback; 1964 rec->flags |= FTRACE_FL_IPMODIFY; 1965 } else /* Removed entry */ 1966 rec->flags &= ~FTRACE_FL_IPMODIFY; 1967 } while_for_each_ftrace_rec(); 1968 1969 return 0; 1970 1971 rollback: 1972 end = rec; 1973 1974 /* Roll back what we did above */ 1975 do_for_each_ftrace_rec(pg, rec) { 1976 1977 if (rec->flags & FTRACE_FL_DISABLED) 1978 continue; 1979 1980 if (rec == end) 1981 goto err_out; 1982 1983 in_old = !!ftrace_lookup_ip(old_hash, rec->ip); 1984 in_new = !!ftrace_lookup_ip(new_hash, rec->ip); 1985 if (in_old == in_new) 1986 continue; 1987 1988 if (in_new) 1989 rec->flags &= ~FTRACE_FL_IPMODIFY; 1990 else 1991 rec->flags |= FTRACE_FL_IPMODIFY; 1992 } while_for_each_ftrace_rec(); 1993 1994 err_out: 1995 return -EBUSY; 1996 } 1997 1998 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops) 1999 { 2000 struct ftrace_hash *hash = ops->func_hash->filter_hash; 2001 2002 if (ftrace_hash_empty(hash)) 2003 hash = NULL; 2004 2005 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash); 2006 } 2007 2008 /* Disabling always succeeds */ 2009 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops) 2010 { 2011 struct ftrace_hash *hash = ops->func_hash->filter_hash; 2012 2013 if (ftrace_hash_empty(hash)) 2014 hash = NULL; 2015 2016 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH); 2017 } 2018 2019 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops, 2020 struct ftrace_hash *new_hash) 2021 { 2022 struct ftrace_hash *old_hash = ops->func_hash->filter_hash; 2023 2024 if (ftrace_hash_empty(old_hash)) 2025 old_hash = NULL; 2026 2027 if (ftrace_hash_empty(new_hash)) 2028 new_hash = NULL; 2029 2030 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash); 2031 } 2032 2033 static void print_ip_ins(const char *fmt, const unsigned char *p) 2034 { 2035 int i; 2036 2037 printk(KERN_CONT "%s", fmt); 2038 2039 for (i = 0; i < MCOUNT_INSN_SIZE; i++) 2040 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]); 2041 } 2042 2043 static struct ftrace_ops * 2044 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec); 2045 static struct ftrace_ops * 2046 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops); 2047 2048 enum ftrace_bug_type ftrace_bug_type; 2049 const void *ftrace_expected; 2050 2051 static void print_bug_type(void) 2052 { 2053 switch (ftrace_bug_type) { 2054 case FTRACE_BUG_UNKNOWN: 2055 break; 2056 case FTRACE_BUG_INIT: 2057 pr_info("Initializing ftrace call sites\n"); 2058 break; 2059 case FTRACE_BUG_NOP: 2060 pr_info("Setting ftrace call site to NOP\n"); 2061 break; 2062 case FTRACE_BUG_CALL: 2063 pr_info("Setting ftrace call site to call ftrace function\n"); 2064 break; 2065 case FTRACE_BUG_UPDATE: 2066 pr_info("Updating ftrace call site to call a different ftrace function\n"); 2067 break; 2068 } 2069 } 2070 2071 /** 2072 * ftrace_bug - report and shutdown function tracer 2073 * @failed: The failed type (EFAULT, EINVAL, EPERM) 2074 * @rec: The record that failed 2075 * 2076 * The arch code that enables or disables the function tracing 2077 * can call ftrace_bug() when it has detected a problem in 2078 * modifying the code. @failed should be one of either: 2079 * EFAULT - if the problem happens on reading the @ip address 2080 * EINVAL - if what is read at @ip is not what was expected 2081 * EPERM - if the problem happens on writting to the @ip address 2082 */ 2083 void ftrace_bug(int failed, struct dyn_ftrace *rec) 2084 { 2085 unsigned long ip = rec ? rec->ip : 0; 2086 2087 switch (failed) { 2088 case -EFAULT: 2089 FTRACE_WARN_ON_ONCE(1); 2090 pr_info("ftrace faulted on modifying "); 2091 print_ip_sym(ip); 2092 break; 2093 case -EINVAL: 2094 FTRACE_WARN_ON_ONCE(1); 2095 pr_info("ftrace failed to modify "); 2096 print_ip_sym(ip); 2097 print_ip_ins(" actual: ", (unsigned char *)ip); 2098 pr_cont("\n"); 2099 if (ftrace_expected) { 2100 print_ip_ins(" expected: ", ftrace_expected); 2101 pr_cont("\n"); 2102 } 2103 break; 2104 case -EPERM: 2105 FTRACE_WARN_ON_ONCE(1); 2106 pr_info("ftrace faulted on writing "); 2107 print_ip_sym(ip); 2108 break; 2109 default: 2110 FTRACE_WARN_ON_ONCE(1); 2111 pr_info("ftrace faulted on unknown error "); 2112 print_ip_sym(ip); 2113 } 2114 print_bug_type(); 2115 if (rec) { 2116 struct ftrace_ops *ops = NULL; 2117 2118 pr_info("ftrace record flags: %lx\n", rec->flags); 2119 pr_cont(" (%ld)%s", ftrace_rec_count(rec), 2120 rec->flags & FTRACE_FL_REGS ? " R" : " "); 2121 if (rec->flags & FTRACE_FL_TRAMP_EN) { 2122 ops = ftrace_find_tramp_ops_any(rec); 2123 if (ops) { 2124 do { 2125 pr_cont("\ttramp: %pS (%pS)", 2126 (void *)ops->trampoline, 2127 (void *)ops->func); 2128 ops = ftrace_find_tramp_ops_next(rec, ops); 2129 } while (ops); 2130 } else 2131 pr_cont("\ttramp: ERROR!"); 2132 2133 } 2134 ip = ftrace_get_addr_curr(rec); 2135 pr_cont("\n expected tramp: %lx\n", ip); 2136 } 2137 } 2138 2139 static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) 2140 { 2141 unsigned long flag = 0UL; 2142 2143 ftrace_bug_type = FTRACE_BUG_UNKNOWN; 2144 2145 if (rec->flags & FTRACE_FL_DISABLED) 2146 return FTRACE_UPDATE_IGNORE; 2147 2148 /* 2149 * If we are updating calls: 2150 * 2151 * If the record has a ref count, then we need to enable it 2152 * because someone is using it. 2153 * 2154 * Otherwise we make sure its disabled. 2155 * 2156 * If we are disabling calls, then disable all records that 2157 * are enabled. 2158 */ 2159 if (enable && ftrace_rec_count(rec)) 2160 flag = FTRACE_FL_ENABLED; 2161 2162 /* 2163 * If enabling and the REGS flag does not match the REGS_EN, or 2164 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore 2165 * this record. Set flags to fail the compare against ENABLED. 2166 */ 2167 if (flag) { 2168 if (!(rec->flags & FTRACE_FL_REGS) != 2169 !(rec->flags & FTRACE_FL_REGS_EN)) 2170 flag |= FTRACE_FL_REGS; 2171 2172 if (!(rec->flags & FTRACE_FL_TRAMP) != 2173 !(rec->flags & FTRACE_FL_TRAMP_EN)) 2174 flag |= FTRACE_FL_TRAMP; 2175 } 2176 2177 /* If the state of this record hasn't changed, then do nothing */ 2178 if ((rec->flags & FTRACE_FL_ENABLED) == flag) 2179 return FTRACE_UPDATE_IGNORE; 2180 2181 if (flag) { 2182 /* Save off if rec is being enabled (for return value) */ 2183 flag ^= rec->flags & FTRACE_FL_ENABLED; 2184 2185 if (update) { 2186 rec->flags |= FTRACE_FL_ENABLED; 2187 if (flag & FTRACE_FL_REGS) { 2188 if (rec->flags & FTRACE_FL_REGS) 2189 rec->flags |= FTRACE_FL_REGS_EN; 2190 else 2191 rec->flags &= ~FTRACE_FL_REGS_EN; 2192 } 2193 if (flag & FTRACE_FL_TRAMP) { 2194 if (rec->flags & FTRACE_FL_TRAMP) 2195 rec->flags |= FTRACE_FL_TRAMP_EN; 2196 else 2197 rec->flags &= ~FTRACE_FL_TRAMP_EN; 2198 } 2199 } 2200 2201 /* 2202 * If this record is being updated from a nop, then 2203 * return UPDATE_MAKE_CALL. 2204 * Otherwise, 2205 * return UPDATE_MODIFY_CALL to tell the caller to convert 2206 * from the save regs, to a non-save regs function or 2207 * vice versa, or from a trampoline call. 2208 */ 2209 if (flag & FTRACE_FL_ENABLED) { 2210 ftrace_bug_type = FTRACE_BUG_CALL; 2211 return FTRACE_UPDATE_MAKE_CALL; 2212 } 2213 2214 ftrace_bug_type = FTRACE_BUG_UPDATE; 2215 return FTRACE_UPDATE_MODIFY_CALL; 2216 } 2217 2218 if (update) { 2219 /* If there's no more users, clear all flags */ 2220 if (!ftrace_rec_count(rec)) 2221 rec->flags = 0; 2222 else 2223 /* 2224 * Just disable the record, but keep the ops TRAMP 2225 * and REGS states. The _EN flags must be disabled though. 2226 */ 2227 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN | 2228 FTRACE_FL_REGS_EN); 2229 } 2230 2231 ftrace_bug_type = FTRACE_BUG_NOP; 2232 return FTRACE_UPDATE_MAKE_NOP; 2233 } 2234 2235 /** 2236 * ftrace_update_record, set a record that now is tracing or not 2237 * @rec: the record to update 2238 * @enable: set to 1 if the record is tracing, zero to force disable 2239 * 2240 * The records that represent all functions that can be traced need 2241 * to be updated when tracing has been enabled. 2242 */ 2243 int ftrace_update_record(struct dyn_ftrace *rec, int enable) 2244 { 2245 return ftrace_check_record(rec, enable, 1); 2246 } 2247 2248 /** 2249 * ftrace_test_record, check if the record has been enabled or not 2250 * @rec: the record to test 2251 * @enable: set to 1 to check if enabled, 0 if it is disabled 2252 * 2253 * The arch code may need to test if a record is already set to 2254 * tracing to determine how to modify the function code that it 2255 * represents. 2256 */ 2257 int ftrace_test_record(struct dyn_ftrace *rec, int enable) 2258 { 2259 return ftrace_check_record(rec, enable, 0); 2260 } 2261 2262 static struct ftrace_ops * 2263 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec) 2264 { 2265 struct ftrace_ops *op; 2266 unsigned long ip = rec->ip; 2267 2268 do_for_each_ftrace_op(op, ftrace_ops_list) { 2269 2270 if (!op->trampoline) 2271 continue; 2272 2273 if (hash_contains_ip(ip, op->func_hash)) 2274 return op; 2275 } while_for_each_ftrace_op(op); 2276 2277 return NULL; 2278 } 2279 2280 static struct ftrace_ops * 2281 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, 2282 struct ftrace_ops *op) 2283 { 2284 unsigned long ip = rec->ip; 2285 2286 while_for_each_ftrace_op(op) { 2287 2288 if (!op->trampoline) 2289 continue; 2290 2291 if (hash_contains_ip(ip, op->func_hash)) 2292 return op; 2293 } 2294 2295 return NULL; 2296 } 2297 2298 static struct ftrace_ops * 2299 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec) 2300 { 2301 struct ftrace_ops *op; 2302 unsigned long ip = rec->ip; 2303 2304 /* 2305 * Need to check removed ops first. 2306 * If they are being removed, and this rec has a tramp, 2307 * and this rec is in the ops list, then it would be the 2308 * one with the tramp. 2309 */ 2310 if (removed_ops) { 2311 if (hash_contains_ip(ip, &removed_ops->old_hash)) 2312 return removed_ops; 2313 } 2314 2315 /* 2316 * Need to find the current trampoline for a rec. 2317 * Now, a trampoline is only attached to a rec if there 2318 * was a single 'ops' attached to it. But this can be called 2319 * when we are adding another op to the rec or removing the 2320 * current one. Thus, if the op is being added, we can 2321 * ignore it because it hasn't attached itself to the rec 2322 * yet. 2323 * 2324 * If an ops is being modified (hooking to different functions) 2325 * then we don't care about the new functions that are being 2326 * added, just the old ones (that are probably being removed). 2327 * 2328 * If we are adding an ops to a function that already is using 2329 * a trampoline, it needs to be removed (trampolines are only 2330 * for single ops connected), then an ops that is not being 2331 * modified also needs to be checked. 2332 */ 2333 do_for_each_ftrace_op(op, ftrace_ops_list) { 2334 2335 if (!op->trampoline) 2336 continue; 2337 2338 /* 2339 * If the ops is being added, it hasn't gotten to 2340 * the point to be removed from this tree yet. 2341 */ 2342 if (op->flags & FTRACE_OPS_FL_ADDING) 2343 continue; 2344 2345 2346 /* 2347 * If the ops is being modified and is in the old 2348 * hash, then it is probably being removed from this 2349 * function. 2350 */ 2351 if ((op->flags & FTRACE_OPS_FL_MODIFYING) && 2352 hash_contains_ip(ip, &op->old_hash)) 2353 return op; 2354 /* 2355 * If the ops is not being added or modified, and it's 2356 * in its normal filter hash, then this must be the one 2357 * we want! 2358 */ 2359 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) && 2360 hash_contains_ip(ip, op->func_hash)) 2361 return op; 2362 2363 } while_for_each_ftrace_op(op); 2364 2365 return NULL; 2366 } 2367 2368 static struct ftrace_ops * 2369 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec) 2370 { 2371 struct ftrace_ops *op; 2372 unsigned long ip = rec->ip; 2373 2374 do_for_each_ftrace_op(op, ftrace_ops_list) { 2375 /* pass rec in as regs to have non-NULL val */ 2376 if (hash_contains_ip(ip, op->func_hash)) 2377 return op; 2378 } while_for_each_ftrace_op(op); 2379 2380 return NULL; 2381 } 2382 2383 /** 2384 * ftrace_get_addr_new - Get the call address to set to 2385 * @rec: The ftrace record descriptor 2386 * 2387 * If the record has the FTRACE_FL_REGS set, that means that it 2388 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS 2389 * is not not set, then it wants to convert to the normal callback. 2390 * 2391 * Returns the address of the trampoline to set to 2392 */ 2393 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) 2394 { 2395 struct ftrace_ops *ops; 2396 2397 /* Trampolines take precedence over regs */ 2398 if (rec->flags & FTRACE_FL_TRAMP) { 2399 ops = ftrace_find_tramp_ops_new(rec); 2400 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) { 2401 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n", 2402 (void *)rec->ip, (void *)rec->ip, rec->flags); 2403 /* Ftrace is shutting down, return anything */ 2404 return (unsigned long)FTRACE_ADDR; 2405 } 2406 return ops->trampoline; 2407 } 2408 2409 if (rec->flags & FTRACE_FL_REGS) 2410 return (unsigned long)FTRACE_REGS_ADDR; 2411 else 2412 return (unsigned long)FTRACE_ADDR; 2413 } 2414 2415 /** 2416 * ftrace_get_addr_curr - Get the call address that is already there 2417 * @rec: The ftrace record descriptor 2418 * 2419 * The FTRACE_FL_REGS_EN is set when the record already points to 2420 * a function that saves all the regs. Basically the '_EN' version 2421 * represents the current state of the function. 2422 * 2423 * Returns the address of the trampoline that is currently being called 2424 */ 2425 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec) 2426 { 2427 struct ftrace_ops *ops; 2428 2429 /* Trampolines take precedence over regs */ 2430 if (rec->flags & FTRACE_FL_TRAMP_EN) { 2431 ops = ftrace_find_tramp_ops_curr(rec); 2432 if (FTRACE_WARN_ON(!ops)) { 2433 pr_warn("Bad trampoline accounting at: %p (%pS)\n", 2434 (void *)rec->ip, (void *)rec->ip); 2435 /* Ftrace is shutting down, return anything */ 2436 return (unsigned long)FTRACE_ADDR; 2437 } 2438 return ops->trampoline; 2439 } 2440 2441 if (rec->flags & FTRACE_FL_REGS_EN) 2442 return (unsigned long)FTRACE_REGS_ADDR; 2443 else 2444 return (unsigned long)FTRACE_ADDR; 2445 } 2446 2447 static int 2448 __ftrace_replace_code(struct dyn_ftrace *rec, int enable) 2449 { 2450 unsigned long ftrace_old_addr; 2451 unsigned long ftrace_addr; 2452 int ret; 2453 2454 ftrace_addr = ftrace_get_addr_new(rec); 2455 2456 /* This needs to be done before we call ftrace_update_record */ 2457 ftrace_old_addr = ftrace_get_addr_curr(rec); 2458 2459 ret = ftrace_update_record(rec, enable); 2460 2461 ftrace_bug_type = FTRACE_BUG_UNKNOWN; 2462 2463 switch (ret) { 2464 case FTRACE_UPDATE_IGNORE: 2465 return 0; 2466 2467 case FTRACE_UPDATE_MAKE_CALL: 2468 ftrace_bug_type = FTRACE_BUG_CALL; 2469 return ftrace_make_call(rec, ftrace_addr); 2470 2471 case FTRACE_UPDATE_MAKE_NOP: 2472 ftrace_bug_type = FTRACE_BUG_NOP; 2473 return ftrace_make_nop(NULL, rec, ftrace_old_addr); 2474 2475 case FTRACE_UPDATE_MODIFY_CALL: 2476 ftrace_bug_type = FTRACE_BUG_UPDATE; 2477 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr); 2478 } 2479 2480 return -1; /* unknow ftrace bug */ 2481 } 2482 2483 void __weak ftrace_replace_code(int enable) 2484 { 2485 struct dyn_ftrace *rec; 2486 struct ftrace_page *pg; 2487 int failed; 2488 2489 if (unlikely(ftrace_disabled)) 2490 return; 2491 2492 do_for_each_ftrace_rec(pg, rec) { 2493 2494 if (rec->flags & FTRACE_FL_DISABLED) 2495 continue; 2496 2497 failed = __ftrace_replace_code(rec, enable); 2498 if (failed) { 2499 ftrace_bug(failed, rec); 2500 /* Stop processing */ 2501 return; 2502 } 2503 } while_for_each_ftrace_rec(); 2504 } 2505 2506 struct ftrace_rec_iter { 2507 struct ftrace_page *pg; 2508 int index; 2509 }; 2510 2511 /** 2512 * ftrace_rec_iter_start, start up iterating over traced functions 2513 * 2514 * Returns an iterator handle that is used to iterate over all 2515 * the records that represent address locations where functions 2516 * are traced. 2517 * 2518 * May return NULL if no records are available. 2519 */ 2520 struct ftrace_rec_iter *ftrace_rec_iter_start(void) 2521 { 2522 /* 2523 * We only use a single iterator. 2524 * Protected by the ftrace_lock mutex. 2525 */ 2526 static struct ftrace_rec_iter ftrace_rec_iter; 2527 struct ftrace_rec_iter *iter = &ftrace_rec_iter; 2528 2529 iter->pg = ftrace_pages_start; 2530 iter->index = 0; 2531 2532 /* Could have empty pages */ 2533 while (iter->pg && !iter->pg->index) 2534 iter->pg = iter->pg->next; 2535 2536 if (!iter->pg) 2537 return NULL; 2538 2539 return iter; 2540 } 2541 2542 /** 2543 * ftrace_rec_iter_next, get the next record to process. 2544 * @iter: The handle to the iterator. 2545 * 2546 * Returns the next iterator after the given iterator @iter. 2547 */ 2548 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter) 2549 { 2550 iter->index++; 2551 2552 if (iter->index >= iter->pg->index) { 2553 iter->pg = iter->pg->next; 2554 iter->index = 0; 2555 2556 /* Could have empty pages */ 2557 while (iter->pg && !iter->pg->index) 2558 iter->pg = iter->pg->next; 2559 } 2560 2561 if (!iter->pg) 2562 return NULL; 2563 2564 return iter; 2565 } 2566 2567 /** 2568 * ftrace_rec_iter_record, get the record at the iterator location 2569 * @iter: The current iterator location 2570 * 2571 * Returns the record that the current @iter is at. 2572 */ 2573 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter) 2574 { 2575 return &iter->pg->records[iter->index]; 2576 } 2577 2578 static int 2579 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec) 2580 { 2581 int ret; 2582 2583 if (unlikely(ftrace_disabled)) 2584 return 0; 2585 2586 ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR); 2587 if (ret) { 2588 ftrace_bug_type = FTRACE_BUG_INIT; 2589 ftrace_bug(ret, rec); 2590 return 0; 2591 } 2592 return 1; 2593 } 2594 2595 /* 2596 * archs can override this function if they must do something 2597 * before the modifying code is performed. 2598 */ 2599 int __weak ftrace_arch_code_modify_prepare(void) 2600 { 2601 return 0; 2602 } 2603 2604 /* 2605 * archs can override this function if they must do something 2606 * after the modifying code is performed. 2607 */ 2608 int __weak ftrace_arch_code_modify_post_process(void) 2609 { 2610 return 0; 2611 } 2612 2613 void ftrace_modify_all_code(int command) 2614 { 2615 int update = command & FTRACE_UPDATE_TRACE_FUNC; 2616 int err = 0; 2617 2618 /* 2619 * If the ftrace_caller calls a ftrace_ops func directly, 2620 * we need to make sure that it only traces functions it 2621 * expects to trace. When doing the switch of functions, 2622 * we need to update to the ftrace_ops_list_func first 2623 * before the transition between old and new calls are set, 2624 * as the ftrace_ops_list_func will check the ops hashes 2625 * to make sure the ops are having the right functions 2626 * traced. 2627 */ 2628 if (update) { 2629 err = ftrace_update_ftrace_func(ftrace_ops_list_func); 2630 if (FTRACE_WARN_ON(err)) 2631 return; 2632 } 2633 2634 if (command & FTRACE_UPDATE_CALLS) 2635 ftrace_replace_code(1); 2636 else if (command & FTRACE_DISABLE_CALLS) 2637 ftrace_replace_code(0); 2638 2639 if (update && ftrace_trace_function != ftrace_ops_list_func) { 2640 function_trace_op = set_function_trace_op; 2641 smp_wmb(); 2642 /* If irqs are disabled, we are in stop machine */ 2643 if (!irqs_disabled()) 2644 smp_call_function(ftrace_sync_ipi, NULL, 1); 2645 err = ftrace_update_ftrace_func(ftrace_trace_function); 2646 if (FTRACE_WARN_ON(err)) 2647 return; 2648 } 2649 2650 if (command & FTRACE_START_FUNC_RET) 2651 err = ftrace_enable_ftrace_graph_caller(); 2652 else if (command & FTRACE_STOP_FUNC_RET) 2653 err = ftrace_disable_ftrace_graph_caller(); 2654 FTRACE_WARN_ON(err); 2655 } 2656 2657 static int __ftrace_modify_code(void *data) 2658 { 2659 int *command = data; 2660 2661 ftrace_modify_all_code(*command); 2662 2663 return 0; 2664 } 2665 2666 /** 2667 * ftrace_run_stop_machine, go back to the stop machine method 2668 * @command: The command to tell ftrace what to do 2669 * 2670 * If an arch needs to fall back to the stop machine method, the 2671 * it can call this function. 2672 */ 2673 void ftrace_run_stop_machine(int command) 2674 { 2675 stop_machine(__ftrace_modify_code, &command, NULL); 2676 } 2677 2678 /** 2679 * arch_ftrace_update_code, modify the code to trace or not trace 2680 * @command: The command that needs to be done 2681 * 2682 * Archs can override this function if it does not need to 2683 * run stop_machine() to modify code. 2684 */ 2685 void __weak arch_ftrace_update_code(int command) 2686 { 2687 ftrace_run_stop_machine(command); 2688 } 2689 2690 static void ftrace_run_update_code(int command) 2691 { 2692 int ret; 2693 2694 ret = ftrace_arch_code_modify_prepare(); 2695 FTRACE_WARN_ON(ret); 2696 if (ret) 2697 return; 2698 2699 /* 2700 * By default we use stop_machine() to modify the code. 2701 * But archs can do what ever they want as long as it 2702 * is safe. The stop_machine() is the safest, but also 2703 * produces the most overhead. 2704 */ 2705 arch_ftrace_update_code(command); 2706 2707 ret = ftrace_arch_code_modify_post_process(); 2708 FTRACE_WARN_ON(ret); 2709 } 2710 2711 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command, 2712 struct ftrace_ops_hash *old_hash) 2713 { 2714 ops->flags |= FTRACE_OPS_FL_MODIFYING; 2715 ops->old_hash.filter_hash = old_hash->filter_hash; 2716 ops->old_hash.notrace_hash = old_hash->notrace_hash; 2717 ftrace_run_update_code(command); 2718 ops->old_hash.filter_hash = NULL; 2719 ops->old_hash.notrace_hash = NULL; 2720 ops->flags &= ~FTRACE_OPS_FL_MODIFYING; 2721 } 2722 2723 static ftrace_func_t saved_ftrace_func; 2724 static int ftrace_start_up; 2725 2726 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops) 2727 { 2728 } 2729 2730 static void per_cpu_ops_free(struct ftrace_ops *ops) 2731 { 2732 free_percpu(ops->disabled); 2733 } 2734 2735 static void ftrace_startup_enable(int command) 2736 { 2737 if (saved_ftrace_func != ftrace_trace_function) { 2738 saved_ftrace_func = ftrace_trace_function; 2739 command |= FTRACE_UPDATE_TRACE_FUNC; 2740 } 2741 2742 if (!command || !ftrace_enabled) 2743 return; 2744 2745 ftrace_run_update_code(command); 2746 } 2747 2748 static void ftrace_startup_all(int command) 2749 { 2750 update_all_ops = true; 2751 ftrace_startup_enable(command); 2752 update_all_ops = false; 2753 } 2754 2755 static int ftrace_startup(struct ftrace_ops *ops, int command) 2756 { 2757 int ret; 2758 2759 if (unlikely(ftrace_disabled)) 2760 return -ENODEV; 2761 2762 ret = __register_ftrace_function(ops); 2763 if (ret) 2764 return ret; 2765 2766 ftrace_start_up++; 2767 2768 /* 2769 * Note that ftrace probes uses this to start up 2770 * and modify functions it will probe. But we still 2771 * set the ADDING flag for modification, as probes 2772 * do not have trampolines. If they add them in the 2773 * future, then the probes will need to distinguish 2774 * between adding and updating probes. 2775 */ 2776 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING; 2777 2778 ret = ftrace_hash_ipmodify_enable(ops); 2779 if (ret < 0) { 2780 /* Rollback registration process */ 2781 __unregister_ftrace_function(ops); 2782 ftrace_start_up--; 2783 ops->flags &= ~FTRACE_OPS_FL_ENABLED; 2784 return ret; 2785 } 2786 2787 if (ftrace_hash_rec_enable(ops, 1)) 2788 command |= FTRACE_UPDATE_CALLS; 2789 2790 ftrace_startup_enable(command); 2791 2792 ops->flags &= ~FTRACE_OPS_FL_ADDING; 2793 2794 return 0; 2795 } 2796 2797 static int ftrace_shutdown(struct ftrace_ops *ops, int command) 2798 { 2799 int ret; 2800 2801 if (unlikely(ftrace_disabled)) 2802 return -ENODEV; 2803 2804 ret = __unregister_ftrace_function(ops); 2805 if (ret) 2806 return ret; 2807 2808 ftrace_start_up--; 2809 /* 2810 * Just warn in case of unbalance, no need to kill ftrace, it's not 2811 * critical but the ftrace_call callers may be never nopped again after 2812 * further ftrace uses. 2813 */ 2814 WARN_ON_ONCE(ftrace_start_up < 0); 2815 2816 /* Disabling ipmodify never fails */ 2817 ftrace_hash_ipmodify_disable(ops); 2818 2819 if (ftrace_hash_rec_disable(ops, 1)) 2820 command |= FTRACE_UPDATE_CALLS; 2821 2822 ops->flags &= ~FTRACE_OPS_FL_ENABLED; 2823 2824 if (saved_ftrace_func != ftrace_trace_function) { 2825 saved_ftrace_func = ftrace_trace_function; 2826 command |= FTRACE_UPDATE_TRACE_FUNC; 2827 } 2828 2829 if (!command || !ftrace_enabled) { 2830 /* 2831 * If these are per_cpu ops, they still need their 2832 * per_cpu field freed. Since, function tracing is 2833 * not currently active, we can just free them 2834 * without synchronizing all CPUs. 2835 */ 2836 if (ops->flags & FTRACE_OPS_FL_PER_CPU) 2837 per_cpu_ops_free(ops); 2838 return 0; 2839 } 2840 2841 /* 2842 * If the ops uses a trampoline, then it needs to be 2843 * tested first on update. 2844 */ 2845 ops->flags |= FTRACE_OPS_FL_REMOVING; 2846 removed_ops = ops; 2847 2848 /* The trampoline logic checks the old hashes */ 2849 ops->old_hash.filter_hash = ops->func_hash->filter_hash; 2850 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash; 2851 2852 ftrace_run_update_code(command); 2853 2854 /* 2855 * If there's no more ops registered with ftrace, run a 2856 * sanity check to make sure all rec flags are cleared. 2857 */ 2858 if (rcu_dereference_protected(ftrace_ops_list, 2859 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) { 2860 struct ftrace_page *pg; 2861 struct dyn_ftrace *rec; 2862 2863 do_for_each_ftrace_rec(pg, rec) { 2864 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED)) 2865 pr_warn(" %pS flags:%lx\n", 2866 (void *)rec->ip, rec->flags); 2867 } while_for_each_ftrace_rec(); 2868 } 2869 2870 ops->old_hash.filter_hash = NULL; 2871 ops->old_hash.notrace_hash = NULL; 2872 2873 removed_ops = NULL; 2874 ops->flags &= ~FTRACE_OPS_FL_REMOVING; 2875 2876 /* 2877 * Dynamic ops may be freed, we must make sure that all 2878 * callers are done before leaving this function. 2879 * The same goes for freeing the per_cpu data of the per_cpu 2880 * ops. 2881 */ 2882 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) { 2883 /* 2884 * We need to do a hard force of sched synchronization. 2885 * This is because we use preempt_disable() to do RCU, but 2886 * the function tracers can be called where RCU is not watching 2887 * (like before user_exit()). We can not rely on the RCU 2888 * infrastructure to do the synchronization, thus we must do it 2889 * ourselves. 2890 */ 2891 schedule_on_each_cpu(ftrace_sync); 2892 2893 /* 2894 * When the kernel is preeptive, tasks can be preempted 2895 * while on a ftrace trampoline. Just scheduling a task on 2896 * a CPU is not good enough to flush them. Calling 2897 * synchornize_rcu_tasks() will wait for those tasks to 2898 * execute and either schedule voluntarily or enter user space. 2899 */ 2900 if (IS_ENABLED(CONFIG_PREEMPT)) 2901 synchronize_rcu_tasks(); 2902 2903 arch_ftrace_trampoline_free(ops); 2904 2905 if (ops->flags & FTRACE_OPS_FL_PER_CPU) 2906 per_cpu_ops_free(ops); 2907 } 2908 2909 return 0; 2910 } 2911 2912 static void ftrace_startup_sysctl(void) 2913 { 2914 int command; 2915 2916 if (unlikely(ftrace_disabled)) 2917 return; 2918 2919 /* Force update next time */ 2920 saved_ftrace_func = NULL; 2921 /* ftrace_start_up is true if we want ftrace running */ 2922 if (ftrace_start_up) { 2923 command = FTRACE_UPDATE_CALLS; 2924 if (ftrace_graph_active) 2925 command |= FTRACE_START_FUNC_RET; 2926 ftrace_startup_enable(command); 2927 } 2928 } 2929 2930 static void ftrace_shutdown_sysctl(void) 2931 { 2932 int command; 2933 2934 if (unlikely(ftrace_disabled)) 2935 return; 2936 2937 /* ftrace_start_up is true if ftrace is running */ 2938 if (ftrace_start_up) { 2939 command = FTRACE_DISABLE_CALLS; 2940 if (ftrace_graph_active) 2941 command |= FTRACE_STOP_FUNC_RET; 2942 ftrace_run_update_code(command); 2943 } 2944 } 2945 2946 static u64 ftrace_update_time; 2947 unsigned long ftrace_update_tot_cnt; 2948 2949 static inline int ops_traces_mod(struct ftrace_ops *ops) 2950 { 2951 /* 2952 * Filter_hash being empty will default to trace module. 2953 * But notrace hash requires a test of individual module functions. 2954 */ 2955 return ftrace_hash_empty(ops->func_hash->filter_hash) && 2956 ftrace_hash_empty(ops->func_hash->notrace_hash); 2957 } 2958 2959 /* 2960 * Check if the current ops references the record. 2961 * 2962 * If the ops traces all functions, then it was already accounted for. 2963 * If the ops does not trace the current record function, skip it. 2964 * If the ops ignores the function via notrace filter, skip it. 2965 */ 2966 static inline bool 2967 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec) 2968 { 2969 /* If ops isn't enabled, ignore it */ 2970 if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) 2971 return 0; 2972 2973 /* If ops traces all then it includes this function */ 2974 if (ops_traces_mod(ops)) 2975 return 1; 2976 2977 /* The function must be in the filter */ 2978 if (!ftrace_hash_empty(ops->func_hash->filter_hash) && 2979 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip)) 2980 return 0; 2981 2982 /* If in notrace hash, we ignore it too */ 2983 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) 2984 return 0; 2985 2986 return 1; 2987 } 2988 2989 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs) 2990 { 2991 struct ftrace_page *pg; 2992 struct dyn_ftrace *p; 2993 u64 start, stop; 2994 unsigned long update_cnt = 0; 2995 unsigned long rec_flags = 0; 2996 int i; 2997 2998 start = ftrace_now(raw_smp_processor_id()); 2999 3000 /* 3001 * When a module is loaded, this function is called to convert 3002 * the calls to mcount in its text to nops, and also to create 3003 * an entry in the ftrace data. Now, if ftrace is activated 3004 * after this call, but before the module sets its text to 3005 * read-only, the modification of enabling ftrace can fail if 3006 * the read-only is done while ftrace is converting the calls. 3007 * To prevent this, the module's records are set as disabled 3008 * and will be enabled after the call to set the module's text 3009 * to read-only. 3010 */ 3011 if (mod) 3012 rec_flags |= FTRACE_FL_DISABLED; 3013 3014 for (pg = new_pgs; pg; pg = pg->next) { 3015 3016 for (i = 0; i < pg->index; i++) { 3017 3018 /* If something went wrong, bail without enabling anything */ 3019 if (unlikely(ftrace_disabled)) 3020 return -1; 3021 3022 p = &pg->records[i]; 3023 p->flags = rec_flags; 3024 3025 /* 3026 * Do the initial record conversion from mcount jump 3027 * to the NOP instructions. 3028 */ 3029 if (!ftrace_code_disable(mod, p)) 3030 break; 3031 3032 update_cnt++; 3033 } 3034 } 3035 3036 stop = ftrace_now(raw_smp_processor_id()); 3037 ftrace_update_time = stop - start; 3038 ftrace_update_tot_cnt += update_cnt; 3039 3040 return 0; 3041 } 3042 3043 static int ftrace_allocate_records(struct ftrace_page *pg, int count) 3044 { 3045 int order; 3046 int cnt; 3047 3048 if (WARN_ON(!count)) 3049 return -EINVAL; 3050 3051 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE)); 3052 3053 /* 3054 * We want to fill as much as possible. No more than a page 3055 * may be empty. 3056 */ 3057 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE) 3058 order--; 3059 3060 again: 3061 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order); 3062 3063 if (!pg->records) { 3064 /* if we can't allocate this size, try something smaller */ 3065 if (!order) 3066 return -ENOMEM; 3067 order >>= 1; 3068 goto again; 3069 } 3070 3071 cnt = (PAGE_SIZE << order) / ENTRY_SIZE; 3072 pg->size = cnt; 3073 3074 if (cnt > count) 3075 cnt = count; 3076 3077 return cnt; 3078 } 3079 3080 static struct ftrace_page * 3081 ftrace_allocate_pages(unsigned long num_to_init) 3082 { 3083 struct ftrace_page *start_pg; 3084 struct ftrace_page *pg; 3085 int order; 3086 int cnt; 3087 3088 if (!num_to_init) 3089 return 0; 3090 3091 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL); 3092 if (!pg) 3093 return NULL; 3094 3095 /* 3096 * Try to allocate as much as possible in one continues 3097 * location that fills in all of the space. We want to 3098 * waste as little space as possible. 3099 */ 3100 for (;;) { 3101 cnt = ftrace_allocate_records(pg, num_to_init); 3102 if (cnt < 0) 3103 goto free_pages; 3104 3105 num_to_init -= cnt; 3106 if (!num_to_init) 3107 break; 3108 3109 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL); 3110 if (!pg->next) 3111 goto free_pages; 3112 3113 pg = pg->next; 3114 } 3115 3116 return start_pg; 3117 3118 free_pages: 3119 pg = start_pg; 3120 while (pg) { 3121 order = get_count_order(pg->size / ENTRIES_PER_PAGE); 3122 free_pages((unsigned long)pg->records, order); 3123 start_pg = pg->next; 3124 kfree(pg); 3125 pg = start_pg; 3126 } 3127 pr_info("ftrace: FAILED to allocate memory for functions\n"); 3128 return NULL; 3129 } 3130 3131 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ 3132 3133 struct ftrace_iterator { 3134 loff_t pos; 3135 loff_t func_pos; 3136 loff_t mod_pos; 3137 struct ftrace_page *pg; 3138 struct dyn_ftrace *func; 3139 struct ftrace_func_probe *probe; 3140 struct ftrace_func_entry *probe_entry; 3141 struct trace_parser parser; 3142 struct ftrace_hash *hash; 3143 struct ftrace_ops *ops; 3144 struct trace_array *tr; 3145 struct list_head *mod_list; 3146 int pidx; 3147 int idx; 3148 unsigned flags; 3149 }; 3150 3151 static void * 3152 t_probe_next(struct seq_file *m, loff_t *pos) 3153 { 3154 struct ftrace_iterator *iter = m->private; 3155 struct trace_array *tr = iter->ops->private; 3156 struct list_head *func_probes; 3157 struct ftrace_hash *hash; 3158 struct list_head *next; 3159 struct hlist_node *hnd = NULL; 3160 struct hlist_head *hhd; 3161 int size; 3162 3163 (*pos)++; 3164 iter->pos = *pos; 3165 3166 if (!tr) 3167 return NULL; 3168 3169 func_probes = &tr->func_probes; 3170 if (list_empty(func_probes)) 3171 return NULL; 3172 3173 if (!iter->probe) { 3174 next = func_probes->next; 3175 iter->probe = list_entry(next, struct ftrace_func_probe, list); 3176 } 3177 3178 if (iter->probe_entry) 3179 hnd = &iter->probe_entry->hlist; 3180 3181 hash = iter->probe->ops.func_hash->filter_hash; 3182 size = 1 << hash->size_bits; 3183 3184 retry: 3185 if (iter->pidx >= size) { 3186 if (iter->probe->list.next == func_probes) 3187 return NULL; 3188 next = iter->probe->list.next; 3189 iter->probe = list_entry(next, struct ftrace_func_probe, list); 3190 hash = iter->probe->ops.func_hash->filter_hash; 3191 size = 1 << hash->size_bits; 3192 iter->pidx = 0; 3193 } 3194 3195 hhd = &hash->buckets[iter->pidx]; 3196 3197 if (hlist_empty(hhd)) { 3198 iter->pidx++; 3199 hnd = NULL; 3200 goto retry; 3201 } 3202 3203 if (!hnd) 3204 hnd = hhd->first; 3205 else { 3206 hnd = hnd->next; 3207 if (!hnd) { 3208 iter->pidx++; 3209 goto retry; 3210 } 3211 } 3212 3213 if (WARN_ON_ONCE(!hnd)) 3214 return NULL; 3215 3216 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist); 3217 3218 return iter; 3219 } 3220 3221 static void *t_probe_start(struct seq_file *m, loff_t *pos) 3222 { 3223 struct ftrace_iterator *iter = m->private; 3224 void *p = NULL; 3225 loff_t l; 3226 3227 if (!(iter->flags & FTRACE_ITER_DO_PROBES)) 3228 return NULL; 3229 3230 if (iter->mod_pos > *pos) 3231 return NULL; 3232 3233 iter->probe = NULL; 3234 iter->probe_entry = NULL; 3235 iter->pidx = 0; 3236 for (l = 0; l <= (*pos - iter->mod_pos); ) { 3237 p = t_probe_next(m, &l); 3238 if (!p) 3239 break; 3240 } 3241 if (!p) 3242 return NULL; 3243 3244 /* Only set this if we have an item */ 3245 iter->flags |= FTRACE_ITER_PROBE; 3246 3247 return iter; 3248 } 3249 3250 static int 3251 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter) 3252 { 3253 struct ftrace_func_entry *probe_entry; 3254 struct ftrace_probe_ops *probe_ops; 3255 struct ftrace_func_probe *probe; 3256 3257 probe = iter->probe; 3258 probe_entry = iter->probe_entry; 3259 3260 if (WARN_ON_ONCE(!probe || !probe_entry)) 3261 return -EIO; 3262 3263 probe_ops = probe->probe_ops; 3264 3265 if (probe_ops->print) 3266 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data); 3267 3268 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip, 3269 (void *)probe_ops->func); 3270 3271 return 0; 3272 } 3273 3274 static void * 3275 t_mod_next(struct seq_file *m, loff_t *pos) 3276 { 3277 struct ftrace_iterator *iter = m->private; 3278 struct trace_array *tr = iter->tr; 3279 3280 (*pos)++; 3281 iter->pos = *pos; 3282 3283 iter->mod_list = iter->mod_list->next; 3284 3285 if (iter->mod_list == &tr->mod_trace || 3286 iter->mod_list == &tr->mod_notrace) { 3287 iter->flags &= ~FTRACE_ITER_MOD; 3288 return NULL; 3289 } 3290 3291 iter->mod_pos = *pos; 3292 3293 return iter; 3294 } 3295 3296 static void *t_mod_start(struct seq_file *m, loff_t *pos) 3297 { 3298 struct ftrace_iterator *iter = m->private; 3299 void *p = NULL; 3300 loff_t l; 3301 3302 if (iter->func_pos > *pos) 3303 return NULL; 3304 3305 iter->mod_pos = iter->func_pos; 3306 3307 /* probes are only available if tr is set */ 3308 if (!iter->tr) 3309 return NULL; 3310 3311 for (l = 0; l <= (*pos - iter->func_pos); ) { 3312 p = t_mod_next(m, &l); 3313 if (!p) 3314 break; 3315 } 3316 if (!p) { 3317 iter->flags &= ~FTRACE_ITER_MOD; 3318 return t_probe_start(m, pos); 3319 } 3320 3321 /* Only set this if we have an item */ 3322 iter->flags |= FTRACE_ITER_MOD; 3323 3324 return iter; 3325 } 3326 3327 static int 3328 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter) 3329 { 3330 struct ftrace_mod_load *ftrace_mod; 3331 struct trace_array *tr = iter->tr; 3332 3333 if (WARN_ON_ONCE(!iter->mod_list) || 3334 iter->mod_list == &tr->mod_trace || 3335 iter->mod_list == &tr->mod_notrace) 3336 return -EIO; 3337 3338 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list); 3339 3340 if (ftrace_mod->func) 3341 seq_printf(m, "%s", ftrace_mod->func); 3342 else 3343 seq_putc(m, '*'); 3344 3345 seq_printf(m, ":mod:%s\n", ftrace_mod->module); 3346 3347 return 0; 3348 } 3349 3350 static void * 3351 t_func_next(struct seq_file *m, loff_t *pos) 3352 { 3353 struct ftrace_iterator *iter = m->private; 3354 struct dyn_ftrace *rec = NULL; 3355 3356 (*pos)++; 3357 3358 retry: 3359 if (iter->idx >= iter->pg->index) { 3360 if (iter->pg->next) { 3361 iter->pg = iter->pg->next; 3362 iter->idx = 0; 3363 goto retry; 3364 } 3365 } else { 3366 rec = &iter->pg->records[iter->idx++]; 3367 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) && 3368 !ftrace_lookup_ip(iter->hash, rec->ip)) || 3369 3370 ((iter->flags & FTRACE_ITER_ENABLED) && 3371 !(rec->flags & FTRACE_FL_ENABLED))) { 3372 3373 rec = NULL; 3374 goto retry; 3375 } 3376 } 3377 3378 if (!rec) 3379 return NULL; 3380 3381 iter->pos = iter->func_pos = *pos; 3382 iter->func = rec; 3383 3384 return iter; 3385 } 3386 3387 static void * 3388 t_next(struct seq_file *m, void *v, loff_t *pos) 3389 { 3390 struct ftrace_iterator *iter = m->private; 3391 loff_t l = *pos; /* t_probe_start() must use original pos */ 3392 void *ret; 3393 3394 if (unlikely(ftrace_disabled)) 3395 return NULL; 3396 3397 if (iter->flags & FTRACE_ITER_PROBE) 3398 return t_probe_next(m, pos); 3399 3400 if (iter->flags & FTRACE_ITER_MOD) 3401 return t_mod_next(m, pos); 3402 3403 if (iter->flags & FTRACE_ITER_PRINTALL) { 3404 /* next must increment pos, and t_probe_start does not */ 3405 (*pos)++; 3406 return t_mod_start(m, &l); 3407 } 3408 3409 ret = t_func_next(m, pos); 3410 3411 if (!ret) 3412 return t_mod_start(m, &l); 3413 3414 return ret; 3415 } 3416 3417 static void reset_iter_read(struct ftrace_iterator *iter) 3418 { 3419 iter->pos = 0; 3420 iter->func_pos = 0; 3421 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD); 3422 } 3423 3424 static void *t_start(struct seq_file *m, loff_t *pos) 3425 { 3426 struct ftrace_iterator *iter = m->private; 3427 void *p = NULL; 3428 loff_t l; 3429 3430 mutex_lock(&ftrace_lock); 3431 3432 if (unlikely(ftrace_disabled)) 3433 return NULL; 3434 3435 /* 3436 * If an lseek was done, then reset and start from beginning. 3437 */ 3438 if (*pos < iter->pos) 3439 reset_iter_read(iter); 3440 3441 /* 3442 * For set_ftrace_filter reading, if we have the filter 3443 * off, we can short cut and just print out that all 3444 * functions are enabled. 3445 */ 3446 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) && 3447 ftrace_hash_empty(iter->hash)) { 3448 iter->func_pos = 1; /* Account for the message */ 3449 if (*pos > 0) 3450 return t_mod_start(m, pos); 3451 iter->flags |= FTRACE_ITER_PRINTALL; 3452 /* reset in case of seek/pread */ 3453 iter->flags &= ~FTRACE_ITER_PROBE; 3454 return iter; 3455 } 3456 3457 if (iter->flags & FTRACE_ITER_MOD) 3458 return t_mod_start(m, pos); 3459 3460 /* 3461 * Unfortunately, we need to restart at ftrace_pages_start 3462 * every time we let go of the ftrace_mutex. This is because 3463 * those pointers can change without the lock. 3464 */ 3465 iter->pg = ftrace_pages_start; 3466 iter->idx = 0; 3467 for (l = 0; l <= *pos; ) { 3468 p = t_func_next(m, &l); 3469 if (!p) 3470 break; 3471 } 3472 3473 if (!p) 3474 return t_mod_start(m, pos); 3475 3476 return iter; 3477 } 3478 3479 static void t_stop(struct seq_file *m, void *p) 3480 { 3481 mutex_unlock(&ftrace_lock); 3482 } 3483 3484 void * __weak 3485 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec) 3486 { 3487 return NULL; 3488 } 3489 3490 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops, 3491 struct dyn_ftrace *rec) 3492 { 3493 void *ptr; 3494 3495 ptr = arch_ftrace_trampoline_func(ops, rec); 3496 if (ptr) 3497 seq_printf(m, " ->%pS", ptr); 3498 } 3499 3500 static int t_show(struct seq_file *m, void *v) 3501 { 3502 struct ftrace_iterator *iter = m->private; 3503 struct dyn_ftrace *rec; 3504 3505 if (iter->flags & FTRACE_ITER_PROBE) 3506 return t_probe_show(m, iter); 3507 3508 if (iter->flags & FTRACE_ITER_MOD) 3509 return t_mod_show(m, iter); 3510 3511 if (iter->flags & FTRACE_ITER_PRINTALL) { 3512 if (iter->flags & FTRACE_ITER_NOTRACE) 3513 seq_puts(m, "#### no functions disabled ####\n"); 3514 else 3515 seq_puts(m, "#### all functions enabled ####\n"); 3516 return 0; 3517 } 3518 3519 rec = iter->func; 3520 3521 if (!rec) 3522 return 0; 3523 3524 seq_printf(m, "%ps", (void *)rec->ip); 3525 if (iter->flags & FTRACE_ITER_ENABLED) { 3526 struct ftrace_ops *ops; 3527 3528 seq_printf(m, " (%ld)%s%s", 3529 ftrace_rec_count(rec), 3530 rec->flags & FTRACE_FL_REGS ? " R" : " ", 3531 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " "); 3532 if (rec->flags & FTRACE_FL_TRAMP_EN) { 3533 ops = ftrace_find_tramp_ops_any(rec); 3534 if (ops) { 3535 do { 3536 seq_printf(m, "\ttramp: %pS (%pS)", 3537 (void *)ops->trampoline, 3538 (void *)ops->func); 3539 add_trampoline_func(m, ops, rec); 3540 ops = ftrace_find_tramp_ops_next(rec, ops); 3541 } while (ops); 3542 } else 3543 seq_puts(m, "\ttramp: ERROR!"); 3544 } else { 3545 add_trampoline_func(m, NULL, rec); 3546 } 3547 } 3548 3549 seq_putc(m, '\n'); 3550 3551 return 0; 3552 } 3553 3554 static const struct seq_operations show_ftrace_seq_ops = { 3555 .start = t_start, 3556 .next = t_next, 3557 .stop = t_stop, 3558 .show = t_show, 3559 }; 3560 3561 static int 3562 ftrace_avail_open(struct inode *inode, struct file *file) 3563 { 3564 struct ftrace_iterator *iter; 3565 3566 if (unlikely(ftrace_disabled)) 3567 return -ENODEV; 3568 3569 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); 3570 if (!iter) 3571 return -ENOMEM; 3572 3573 iter->pg = ftrace_pages_start; 3574 iter->ops = &global_ops; 3575 3576 return 0; 3577 } 3578 3579 static int 3580 ftrace_enabled_open(struct inode *inode, struct file *file) 3581 { 3582 struct ftrace_iterator *iter; 3583 3584 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); 3585 if (!iter) 3586 return -ENOMEM; 3587 3588 iter->pg = ftrace_pages_start; 3589 iter->flags = FTRACE_ITER_ENABLED; 3590 iter->ops = &global_ops; 3591 3592 return 0; 3593 } 3594 3595 /** 3596 * ftrace_regex_open - initialize function tracer filter files 3597 * @ops: The ftrace_ops that hold the hash filters 3598 * @flag: The type of filter to process 3599 * @inode: The inode, usually passed in to your open routine 3600 * @file: The file, usually passed in to your open routine 3601 * 3602 * ftrace_regex_open() initializes the filter files for the 3603 * @ops. Depending on @flag it may process the filter hash or 3604 * the notrace hash of @ops. With this called from the open 3605 * routine, you can use ftrace_filter_write() for the write 3606 * routine if @flag has FTRACE_ITER_FILTER set, or 3607 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set. 3608 * tracing_lseek() should be used as the lseek routine, and 3609 * release must call ftrace_regex_release(). 3610 */ 3611 int 3612 ftrace_regex_open(struct ftrace_ops *ops, int flag, 3613 struct inode *inode, struct file *file) 3614 { 3615 struct ftrace_iterator *iter; 3616 struct ftrace_hash *hash; 3617 struct list_head *mod_head; 3618 struct trace_array *tr = ops->private; 3619 int ret = 0; 3620 3621 ftrace_ops_init(ops); 3622 3623 if (unlikely(ftrace_disabled)) 3624 return -ENODEV; 3625 3626 iter = kzalloc(sizeof(*iter), GFP_KERNEL); 3627 if (!iter) 3628 return -ENOMEM; 3629 3630 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) { 3631 kfree(iter); 3632 return -ENOMEM; 3633 } 3634 3635 iter->ops = ops; 3636 iter->flags = flag; 3637 iter->tr = tr; 3638 3639 mutex_lock(&ops->func_hash->regex_lock); 3640 3641 if (flag & FTRACE_ITER_NOTRACE) { 3642 hash = ops->func_hash->notrace_hash; 3643 mod_head = tr ? &tr->mod_notrace : NULL; 3644 } else { 3645 hash = ops->func_hash->filter_hash; 3646 mod_head = tr ? &tr->mod_trace : NULL; 3647 } 3648 3649 iter->mod_list = mod_head; 3650 3651 if (file->f_mode & FMODE_WRITE) { 3652 const int size_bits = FTRACE_HASH_DEFAULT_BITS; 3653 3654 if (file->f_flags & O_TRUNC) { 3655 iter->hash = alloc_ftrace_hash(size_bits); 3656 clear_ftrace_mod_list(mod_head); 3657 } else { 3658 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash); 3659 } 3660 3661 if (!iter->hash) { 3662 trace_parser_put(&iter->parser); 3663 kfree(iter); 3664 ret = -ENOMEM; 3665 goto out_unlock; 3666 } 3667 } else 3668 iter->hash = hash; 3669 3670 if (file->f_mode & FMODE_READ) { 3671 iter->pg = ftrace_pages_start; 3672 3673 ret = seq_open(file, &show_ftrace_seq_ops); 3674 if (!ret) { 3675 struct seq_file *m = file->private_data; 3676 m->private = iter; 3677 } else { 3678 /* Failed */ 3679 free_ftrace_hash(iter->hash); 3680 trace_parser_put(&iter->parser); 3681 kfree(iter); 3682 } 3683 } else 3684 file->private_data = iter; 3685 3686 out_unlock: 3687 mutex_unlock(&ops->func_hash->regex_lock); 3688 3689 return ret; 3690 } 3691 3692 static int 3693 ftrace_filter_open(struct inode *inode, struct file *file) 3694 { 3695 struct ftrace_ops *ops = inode->i_private; 3696 3697 return ftrace_regex_open(ops, 3698 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES, 3699 inode, file); 3700 } 3701 3702 static int 3703 ftrace_notrace_open(struct inode *inode, struct file *file) 3704 { 3705 struct ftrace_ops *ops = inode->i_private; 3706 3707 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE, 3708 inode, file); 3709 } 3710 3711 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */ 3712 struct ftrace_glob { 3713 char *search; 3714 unsigned len; 3715 int type; 3716 }; 3717 3718 /* 3719 * If symbols in an architecture don't correspond exactly to the user-visible 3720 * name of what they represent, it is possible to define this function to 3721 * perform the necessary adjustments. 3722 */ 3723 char * __weak arch_ftrace_match_adjust(char *str, const char *search) 3724 { 3725 return str; 3726 } 3727 3728 static int ftrace_match(char *str, struct ftrace_glob *g) 3729 { 3730 int matched = 0; 3731 int slen; 3732 3733 str = arch_ftrace_match_adjust(str, g->search); 3734 3735 switch (g->type) { 3736 case MATCH_FULL: 3737 if (strcmp(str, g->search) == 0) 3738 matched = 1; 3739 break; 3740 case MATCH_FRONT_ONLY: 3741 if (strncmp(str, g->search, g->len) == 0) 3742 matched = 1; 3743 break; 3744 case MATCH_MIDDLE_ONLY: 3745 if (strstr(str, g->search)) 3746 matched = 1; 3747 break; 3748 case MATCH_END_ONLY: 3749 slen = strlen(str); 3750 if (slen >= g->len && 3751 memcmp(str + slen - g->len, g->search, g->len) == 0) 3752 matched = 1; 3753 break; 3754 case MATCH_GLOB: 3755 if (glob_match(g->search, str)) 3756 matched = 1; 3757 break; 3758 } 3759 3760 return matched; 3761 } 3762 3763 static int 3764 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter) 3765 { 3766 struct ftrace_func_entry *entry; 3767 int ret = 0; 3768 3769 entry = ftrace_lookup_ip(hash, rec->ip); 3770 if (clear_filter) { 3771 /* Do nothing if it doesn't exist */ 3772 if (!entry) 3773 return 0; 3774 3775 free_hash_entry(hash, entry); 3776 } else { 3777 /* Do nothing if it exists */ 3778 if (entry) 3779 return 0; 3780 3781 ret = add_hash_entry(hash, rec->ip); 3782 } 3783 return ret; 3784 } 3785 3786 static int 3787 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g, 3788 struct ftrace_glob *mod_g, int exclude_mod) 3789 { 3790 char str[KSYM_SYMBOL_LEN]; 3791 char *modname; 3792 3793 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); 3794 3795 if (mod_g) { 3796 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0; 3797 3798 /* blank module name to match all modules */ 3799 if (!mod_g->len) { 3800 /* blank module globbing: modname xor exclude_mod */ 3801 if (!exclude_mod != !modname) 3802 goto func_match; 3803 return 0; 3804 } 3805 3806 /* 3807 * exclude_mod is set to trace everything but the given 3808 * module. If it is set and the module matches, then 3809 * return 0. If it is not set, and the module doesn't match 3810 * also return 0. Otherwise, check the function to see if 3811 * that matches. 3812 */ 3813 if (!mod_matches == !exclude_mod) 3814 return 0; 3815 func_match: 3816 /* blank search means to match all funcs in the mod */ 3817 if (!func_g->len) 3818 return 1; 3819 } 3820 3821 return ftrace_match(str, func_g); 3822 } 3823 3824 static int 3825 match_records(struct ftrace_hash *hash, char *func, int len, char *mod) 3826 { 3827 struct ftrace_page *pg; 3828 struct dyn_ftrace *rec; 3829 struct ftrace_glob func_g = { .type = MATCH_FULL }; 3830 struct ftrace_glob mod_g = { .type = MATCH_FULL }; 3831 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL; 3832 int exclude_mod = 0; 3833 int found = 0; 3834 int ret; 3835 int clear_filter = 0; 3836 3837 if (func) { 3838 func_g.type = filter_parse_regex(func, len, &func_g.search, 3839 &clear_filter); 3840 func_g.len = strlen(func_g.search); 3841 } 3842 3843 if (mod) { 3844 mod_g.type = filter_parse_regex(mod, strlen(mod), 3845 &mod_g.search, &exclude_mod); 3846 mod_g.len = strlen(mod_g.search); 3847 } 3848 3849 mutex_lock(&ftrace_lock); 3850 3851 if (unlikely(ftrace_disabled)) 3852 goto out_unlock; 3853 3854 do_for_each_ftrace_rec(pg, rec) { 3855 3856 if (rec->flags & FTRACE_FL_DISABLED) 3857 continue; 3858 3859 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) { 3860 ret = enter_record(hash, rec, clear_filter); 3861 if (ret < 0) { 3862 found = ret; 3863 goto out_unlock; 3864 } 3865 found = 1; 3866 } 3867 } while_for_each_ftrace_rec(); 3868 out_unlock: 3869 mutex_unlock(&ftrace_lock); 3870 3871 return found; 3872 } 3873 3874 static int 3875 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len) 3876 { 3877 return match_records(hash, buff, len, NULL); 3878 } 3879 3880 static void ftrace_ops_update_code(struct ftrace_ops *ops, 3881 struct ftrace_ops_hash *old_hash) 3882 { 3883 struct ftrace_ops *op; 3884 3885 if (!ftrace_enabled) 3886 return; 3887 3888 if (ops->flags & FTRACE_OPS_FL_ENABLED) { 3889 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash); 3890 return; 3891 } 3892 3893 /* 3894 * If this is the shared global_ops filter, then we need to 3895 * check if there is another ops that shares it, is enabled. 3896 * If so, we still need to run the modify code. 3897 */ 3898 if (ops->func_hash != &global_ops.local_hash) 3899 return; 3900 3901 do_for_each_ftrace_op(op, ftrace_ops_list) { 3902 if (op->func_hash == &global_ops.local_hash && 3903 op->flags & FTRACE_OPS_FL_ENABLED) { 3904 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash); 3905 /* Only need to do this once */ 3906 return; 3907 } 3908 } while_for_each_ftrace_op(op); 3909 } 3910 3911 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops, 3912 struct ftrace_hash **orig_hash, 3913 struct ftrace_hash *hash, 3914 int enable) 3915 { 3916 struct ftrace_ops_hash old_hash_ops; 3917 struct ftrace_hash *old_hash; 3918 int ret; 3919 3920 old_hash = *orig_hash; 3921 old_hash_ops.filter_hash = ops->func_hash->filter_hash; 3922 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash; 3923 ret = ftrace_hash_move(ops, enable, orig_hash, hash); 3924 if (!ret) { 3925 ftrace_ops_update_code(ops, &old_hash_ops); 3926 free_ftrace_hash_rcu(old_hash); 3927 } 3928 return ret; 3929 } 3930 3931 static bool module_exists(const char *module) 3932 { 3933 /* All modules have the symbol __this_module */ 3934 const char this_mod[] = "__this_module"; 3935 const int modname_size = MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 1; 3936 char modname[modname_size + 1]; 3937 unsigned long val; 3938 int n; 3939 3940 n = snprintf(modname, modname_size + 1, "%s:%s", module, this_mod); 3941 3942 if (n > modname_size) 3943 return false; 3944 3945 val = module_kallsyms_lookup_name(modname); 3946 return val != 0; 3947 } 3948 3949 static int cache_mod(struct trace_array *tr, 3950 const char *func, char *module, int enable) 3951 { 3952 struct ftrace_mod_load *ftrace_mod, *n; 3953 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace; 3954 int ret; 3955 3956 mutex_lock(&ftrace_lock); 3957 3958 /* We do not cache inverse filters */ 3959 if (func[0] == '!') { 3960 func++; 3961 ret = -EINVAL; 3962 3963 /* Look to remove this hash */ 3964 list_for_each_entry_safe(ftrace_mod, n, head, list) { 3965 if (strcmp(ftrace_mod->module, module) != 0) 3966 continue; 3967 3968 /* no func matches all */ 3969 if (strcmp(func, "*") == 0 || 3970 (ftrace_mod->func && 3971 strcmp(ftrace_mod->func, func) == 0)) { 3972 ret = 0; 3973 free_ftrace_mod(ftrace_mod); 3974 continue; 3975 } 3976 } 3977 goto out; 3978 } 3979 3980 ret = -EINVAL; 3981 /* We only care about modules that have not been loaded yet */ 3982 if (module_exists(module)) 3983 goto out; 3984 3985 /* Save this string off, and execute it when the module is loaded */ 3986 ret = ftrace_add_mod(tr, func, module, enable); 3987 out: 3988 mutex_unlock(&ftrace_lock); 3989 3990 return ret; 3991 } 3992 3993 static int 3994 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, 3995 int reset, int enable); 3996 3997 #ifdef CONFIG_MODULES 3998 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops, 3999 char *mod, bool enable) 4000 { 4001 struct ftrace_mod_load *ftrace_mod, *n; 4002 struct ftrace_hash **orig_hash, *new_hash; 4003 LIST_HEAD(process_mods); 4004 char *func; 4005 int ret; 4006 4007 mutex_lock(&ops->func_hash->regex_lock); 4008 4009 if (enable) 4010 orig_hash = &ops->func_hash->filter_hash; 4011 else 4012 orig_hash = &ops->func_hash->notrace_hash; 4013 4014 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, 4015 *orig_hash); 4016 if (!new_hash) 4017 goto out; /* warn? */ 4018 4019 mutex_lock(&ftrace_lock); 4020 4021 list_for_each_entry_safe(ftrace_mod, n, head, list) { 4022 4023 if (strcmp(ftrace_mod->module, mod) != 0) 4024 continue; 4025 4026 if (ftrace_mod->func) 4027 func = kstrdup(ftrace_mod->func, GFP_KERNEL); 4028 else 4029 func = kstrdup("*", GFP_KERNEL); 4030 4031 if (!func) /* warn? */ 4032 continue; 4033 4034 list_del(&ftrace_mod->list); 4035 list_add(&ftrace_mod->list, &process_mods); 4036 4037 /* Use the newly allocated func, as it may be "*" */ 4038 kfree(ftrace_mod->func); 4039 ftrace_mod->func = func; 4040 } 4041 4042 mutex_unlock(&ftrace_lock); 4043 4044 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) { 4045 4046 func = ftrace_mod->func; 4047 4048 /* Grabs ftrace_lock, which is why we have this extra step */ 4049 match_records(new_hash, func, strlen(func), mod); 4050 free_ftrace_mod(ftrace_mod); 4051 } 4052 4053 if (enable && list_empty(head)) 4054 new_hash->flags &= ~FTRACE_HASH_FL_MOD; 4055 4056 mutex_lock(&ftrace_lock); 4057 4058 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, 4059 new_hash, enable); 4060 mutex_unlock(&ftrace_lock); 4061 4062 out: 4063 mutex_unlock(&ops->func_hash->regex_lock); 4064 4065 free_ftrace_hash(new_hash); 4066 } 4067 4068 static void process_cached_mods(const char *mod_name) 4069 { 4070 struct trace_array *tr; 4071 char *mod; 4072 4073 mod = kstrdup(mod_name, GFP_KERNEL); 4074 if (!mod) 4075 return; 4076 4077 mutex_lock(&trace_types_lock); 4078 list_for_each_entry(tr, &ftrace_trace_arrays, list) { 4079 if (!list_empty(&tr->mod_trace)) 4080 process_mod_list(&tr->mod_trace, tr->ops, mod, true); 4081 if (!list_empty(&tr->mod_notrace)) 4082 process_mod_list(&tr->mod_notrace, tr->ops, mod, false); 4083 } 4084 mutex_unlock(&trace_types_lock); 4085 4086 kfree(mod); 4087 } 4088 #endif 4089 4090 /* 4091 * We register the module command as a template to show others how 4092 * to register the a command as well. 4093 */ 4094 4095 static int 4096 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash, 4097 char *func_orig, char *cmd, char *module, int enable) 4098 { 4099 char *func; 4100 int ret; 4101 4102 /* match_records() modifies func, and we need the original */ 4103 func = kstrdup(func_orig, GFP_KERNEL); 4104 if (!func) 4105 return -ENOMEM; 4106 4107 /* 4108 * cmd == 'mod' because we only registered this func 4109 * for the 'mod' ftrace_func_command. 4110 * But if you register one func with multiple commands, 4111 * you can tell which command was used by the cmd 4112 * parameter. 4113 */ 4114 ret = match_records(hash, func, strlen(func), module); 4115 kfree(func); 4116 4117 if (!ret) 4118 return cache_mod(tr, func_orig, module, enable); 4119 if (ret < 0) 4120 return ret; 4121 return 0; 4122 } 4123 4124 static struct ftrace_func_command ftrace_mod_cmd = { 4125 .name = "mod", 4126 .func = ftrace_mod_callback, 4127 }; 4128 4129 static int __init ftrace_mod_cmd_init(void) 4130 { 4131 return register_ftrace_command(&ftrace_mod_cmd); 4132 } 4133 core_initcall(ftrace_mod_cmd_init); 4134 4135 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip, 4136 struct ftrace_ops *op, struct pt_regs *pt_regs) 4137 { 4138 struct ftrace_probe_ops *probe_ops; 4139 struct ftrace_func_probe *probe; 4140 4141 probe = container_of(op, struct ftrace_func_probe, ops); 4142 probe_ops = probe->probe_ops; 4143 4144 /* 4145 * Disable preemption for these calls to prevent a RCU grace 4146 * period. This syncs the hash iteration and freeing of items 4147 * on the hash. rcu_read_lock is too dangerous here. 4148 */ 4149 preempt_disable_notrace(); 4150 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data); 4151 preempt_enable_notrace(); 4152 } 4153 4154 struct ftrace_func_map { 4155 struct ftrace_func_entry entry; 4156 void *data; 4157 }; 4158 4159 struct ftrace_func_mapper { 4160 struct ftrace_hash hash; 4161 }; 4162 4163 /** 4164 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper 4165 * 4166 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data. 4167 */ 4168 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void) 4169 { 4170 struct ftrace_hash *hash; 4171 4172 /* 4173 * The mapper is simply a ftrace_hash, but since the entries 4174 * in the hash are not ftrace_func_entry type, we define it 4175 * as a separate structure. 4176 */ 4177 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); 4178 return (struct ftrace_func_mapper *)hash; 4179 } 4180 4181 /** 4182 * ftrace_func_mapper_find_ip - Find some data mapped to an ip 4183 * @mapper: The mapper that has the ip maps 4184 * @ip: the instruction pointer to find the data for 4185 * 4186 * Returns the data mapped to @ip if found otherwise NULL. The return 4187 * is actually the address of the mapper data pointer. The address is 4188 * returned for use cases where the data is no bigger than a long, and 4189 * the user can use the data pointer as its data instead of having to 4190 * allocate more memory for the reference. 4191 */ 4192 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper, 4193 unsigned long ip) 4194 { 4195 struct ftrace_func_entry *entry; 4196 struct ftrace_func_map *map; 4197 4198 entry = ftrace_lookup_ip(&mapper->hash, ip); 4199 if (!entry) 4200 return NULL; 4201 4202 map = (struct ftrace_func_map *)entry; 4203 return &map->data; 4204 } 4205 4206 /** 4207 * ftrace_func_mapper_add_ip - Map some data to an ip 4208 * @mapper: The mapper that has the ip maps 4209 * @ip: The instruction pointer address to map @data to 4210 * @data: The data to map to @ip 4211 * 4212 * Returns 0 on succes otherwise an error. 4213 */ 4214 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper, 4215 unsigned long ip, void *data) 4216 { 4217 struct ftrace_func_entry *entry; 4218 struct ftrace_func_map *map; 4219 4220 entry = ftrace_lookup_ip(&mapper->hash, ip); 4221 if (entry) 4222 return -EBUSY; 4223 4224 map = kmalloc(sizeof(*map), GFP_KERNEL); 4225 if (!map) 4226 return -ENOMEM; 4227 4228 map->entry.ip = ip; 4229 map->data = data; 4230 4231 __add_hash_entry(&mapper->hash, &map->entry); 4232 4233 return 0; 4234 } 4235 4236 /** 4237 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping 4238 * @mapper: The mapper that has the ip maps 4239 * @ip: The instruction pointer address to remove the data from 4240 * 4241 * Returns the data if it is found, otherwise NULL. 4242 * Note, if the data pointer is used as the data itself, (see 4243 * ftrace_func_mapper_find_ip(), then the return value may be meaningless, 4244 * if the data pointer was set to zero. 4245 */ 4246 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper, 4247 unsigned long ip) 4248 { 4249 struct ftrace_func_entry *entry; 4250 struct ftrace_func_map *map; 4251 void *data; 4252 4253 entry = ftrace_lookup_ip(&mapper->hash, ip); 4254 if (!entry) 4255 return NULL; 4256 4257 map = (struct ftrace_func_map *)entry; 4258 data = map->data; 4259 4260 remove_hash_entry(&mapper->hash, entry); 4261 kfree(entry); 4262 4263 return data; 4264 } 4265 4266 /** 4267 * free_ftrace_func_mapper - free a mapping of ips and data 4268 * @mapper: The mapper that has the ip maps 4269 * @free_func: A function to be called on each data item. 4270 * 4271 * This is used to free the function mapper. The @free_func is optional 4272 * and can be used if the data needs to be freed as well. 4273 */ 4274 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper, 4275 ftrace_mapper_func free_func) 4276 { 4277 struct ftrace_func_entry *entry; 4278 struct ftrace_func_map *map; 4279 struct hlist_head *hhd; 4280 int size = 1 << mapper->hash.size_bits; 4281 int i; 4282 4283 if (free_func && mapper->hash.count) { 4284 for (i = 0; i < size; i++) { 4285 hhd = &mapper->hash.buckets[i]; 4286 hlist_for_each_entry(entry, hhd, hlist) { 4287 map = (struct ftrace_func_map *)entry; 4288 free_func(map); 4289 } 4290 } 4291 } 4292 free_ftrace_hash(&mapper->hash); 4293 } 4294 4295 static void release_probe(struct ftrace_func_probe *probe) 4296 { 4297 struct ftrace_probe_ops *probe_ops; 4298 4299 mutex_lock(&ftrace_lock); 4300 4301 WARN_ON(probe->ref <= 0); 4302 4303 /* Subtract the ref that was used to protect this instance */ 4304 probe->ref--; 4305 4306 if (!probe->ref) { 4307 probe_ops = probe->probe_ops; 4308 /* 4309 * Sending zero as ip tells probe_ops to free 4310 * the probe->data itself 4311 */ 4312 if (probe_ops->free) 4313 probe_ops->free(probe_ops, probe->tr, 0, probe->data); 4314 list_del(&probe->list); 4315 kfree(probe); 4316 } 4317 mutex_unlock(&ftrace_lock); 4318 } 4319 4320 static void acquire_probe_locked(struct ftrace_func_probe *probe) 4321 { 4322 /* 4323 * Add one ref to keep it from being freed when releasing the 4324 * ftrace_lock mutex. 4325 */ 4326 probe->ref++; 4327 } 4328 4329 int 4330 register_ftrace_function_probe(char *glob, struct trace_array *tr, 4331 struct ftrace_probe_ops *probe_ops, 4332 void *data) 4333 { 4334 struct ftrace_func_entry *entry; 4335 struct ftrace_func_probe *probe; 4336 struct ftrace_hash **orig_hash; 4337 struct ftrace_hash *old_hash; 4338 struct ftrace_hash *hash; 4339 int count = 0; 4340 int size; 4341 int ret; 4342 int i; 4343 4344 if (WARN_ON(!tr)) 4345 return -EINVAL; 4346 4347 /* We do not support '!' for function probes */ 4348 if (WARN_ON(glob[0] == '!')) 4349 return -EINVAL; 4350 4351 4352 mutex_lock(&ftrace_lock); 4353 /* Check if the probe_ops is already registered */ 4354 list_for_each_entry(probe, &tr->func_probes, list) { 4355 if (probe->probe_ops == probe_ops) 4356 break; 4357 } 4358 if (&probe->list == &tr->func_probes) { 4359 probe = kzalloc(sizeof(*probe), GFP_KERNEL); 4360 if (!probe) { 4361 mutex_unlock(&ftrace_lock); 4362 return -ENOMEM; 4363 } 4364 probe->probe_ops = probe_ops; 4365 probe->ops.func = function_trace_probe_call; 4366 probe->tr = tr; 4367 ftrace_ops_init(&probe->ops); 4368 list_add(&probe->list, &tr->func_probes); 4369 } 4370 4371 acquire_probe_locked(probe); 4372 4373 mutex_unlock(&ftrace_lock); 4374 4375 mutex_lock(&probe->ops.func_hash->regex_lock); 4376 4377 orig_hash = &probe->ops.func_hash->filter_hash; 4378 old_hash = *orig_hash; 4379 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash); 4380 4381 ret = ftrace_match_records(hash, glob, strlen(glob)); 4382 4383 /* Nothing found? */ 4384 if (!ret) 4385 ret = -EINVAL; 4386 4387 if (ret < 0) 4388 goto out; 4389 4390 size = 1 << hash->size_bits; 4391 for (i = 0; i < size; i++) { 4392 hlist_for_each_entry(entry, &hash->buckets[i], hlist) { 4393 if (ftrace_lookup_ip(old_hash, entry->ip)) 4394 continue; 4395 /* 4396 * The caller might want to do something special 4397 * for each function we find. We call the callback 4398 * to give the caller an opportunity to do so. 4399 */ 4400 if (probe_ops->init) { 4401 ret = probe_ops->init(probe_ops, tr, 4402 entry->ip, data, 4403 &probe->data); 4404 if (ret < 0) { 4405 if (probe_ops->free && count) 4406 probe_ops->free(probe_ops, tr, 4407 0, probe->data); 4408 probe->data = NULL; 4409 goto out; 4410 } 4411 } 4412 count++; 4413 } 4414 } 4415 4416 mutex_lock(&ftrace_lock); 4417 4418 if (!count) { 4419 /* Nothing was added? */ 4420 ret = -EINVAL; 4421 goto out_unlock; 4422 } 4423 4424 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash, 4425 hash, 1); 4426 if (ret < 0) 4427 goto err_unlock; 4428 4429 /* One ref for each new function traced */ 4430 probe->ref += count; 4431 4432 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED)) 4433 ret = ftrace_startup(&probe->ops, 0); 4434 4435 out_unlock: 4436 mutex_unlock(&ftrace_lock); 4437 4438 if (!ret) 4439 ret = count; 4440 out: 4441 mutex_unlock(&probe->ops.func_hash->regex_lock); 4442 free_ftrace_hash(hash); 4443 4444 release_probe(probe); 4445 4446 return ret; 4447 4448 err_unlock: 4449 if (!probe_ops->free || !count) 4450 goto out_unlock; 4451 4452 /* Failed to do the move, need to call the free functions */ 4453 for (i = 0; i < size; i++) { 4454 hlist_for_each_entry(entry, &hash->buckets[i], hlist) { 4455 if (ftrace_lookup_ip(old_hash, entry->ip)) 4456 continue; 4457 probe_ops->free(probe_ops, tr, entry->ip, probe->data); 4458 } 4459 } 4460 goto out_unlock; 4461 } 4462 4463 int 4464 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr, 4465 struct ftrace_probe_ops *probe_ops) 4466 { 4467 struct ftrace_ops_hash old_hash_ops; 4468 struct ftrace_func_entry *entry; 4469 struct ftrace_func_probe *probe; 4470 struct ftrace_glob func_g; 4471 struct ftrace_hash **orig_hash; 4472 struct ftrace_hash *old_hash; 4473 struct ftrace_hash *hash = NULL; 4474 struct hlist_node *tmp; 4475 struct hlist_head hhd; 4476 char str[KSYM_SYMBOL_LEN]; 4477 int count = 0; 4478 int i, ret = -ENODEV; 4479 int size; 4480 4481 if (!glob || !strlen(glob) || !strcmp(glob, "*")) 4482 func_g.search = NULL; 4483 else { 4484 int not; 4485 4486 func_g.type = filter_parse_regex(glob, strlen(glob), 4487 &func_g.search, ¬); 4488 func_g.len = strlen(func_g.search); 4489 func_g.search = glob; 4490 4491 /* we do not support '!' for function probes */ 4492 if (WARN_ON(not)) 4493 return -EINVAL; 4494 } 4495 4496 mutex_lock(&ftrace_lock); 4497 /* Check if the probe_ops is already registered */ 4498 list_for_each_entry(probe, &tr->func_probes, list) { 4499 if (probe->probe_ops == probe_ops) 4500 break; 4501 } 4502 if (&probe->list == &tr->func_probes) 4503 goto err_unlock_ftrace; 4504 4505 ret = -EINVAL; 4506 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED)) 4507 goto err_unlock_ftrace; 4508 4509 acquire_probe_locked(probe); 4510 4511 mutex_unlock(&ftrace_lock); 4512 4513 mutex_lock(&probe->ops.func_hash->regex_lock); 4514 4515 orig_hash = &probe->ops.func_hash->filter_hash; 4516 old_hash = *orig_hash; 4517 4518 if (ftrace_hash_empty(old_hash)) 4519 goto out_unlock; 4520 4521 old_hash_ops.filter_hash = old_hash; 4522 /* Probes only have filters */ 4523 old_hash_ops.notrace_hash = NULL; 4524 4525 ret = -ENOMEM; 4526 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash); 4527 if (!hash) 4528 goto out_unlock; 4529 4530 INIT_HLIST_HEAD(&hhd); 4531 4532 size = 1 << hash->size_bits; 4533 for (i = 0; i < size; i++) { 4534 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) { 4535 4536 if (func_g.search) { 4537 kallsyms_lookup(entry->ip, NULL, NULL, 4538 NULL, str); 4539 if (!ftrace_match(str, &func_g)) 4540 continue; 4541 } 4542 count++; 4543 remove_hash_entry(hash, entry); 4544 hlist_add_head(&entry->hlist, &hhd); 4545 } 4546 } 4547 4548 /* Nothing found? */ 4549 if (!count) { 4550 ret = -EINVAL; 4551 goto out_unlock; 4552 } 4553 4554 mutex_lock(&ftrace_lock); 4555 4556 WARN_ON(probe->ref < count); 4557 4558 probe->ref -= count; 4559 4560 if (ftrace_hash_empty(hash)) 4561 ftrace_shutdown(&probe->ops, 0); 4562 4563 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash, 4564 hash, 1); 4565 4566 /* still need to update the function call sites */ 4567 if (ftrace_enabled && !ftrace_hash_empty(hash)) 4568 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS, 4569 &old_hash_ops); 4570 synchronize_sched(); 4571 4572 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) { 4573 hlist_del(&entry->hlist); 4574 if (probe_ops->free) 4575 probe_ops->free(probe_ops, tr, entry->ip, probe->data); 4576 kfree(entry); 4577 } 4578 mutex_unlock(&ftrace_lock); 4579 4580 out_unlock: 4581 mutex_unlock(&probe->ops.func_hash->regex_lock); 4582 free_ftrace_hash(hash); 4583 4584 release_probe(probe); 4585 4586 return ret; 4587 4588 err_unlock_ftrace: 4589 mutex_unlock(&ftrace_lock); 4590 return ret; 4591 } 4592 4593 void clear_ftrace_function_probes(struct trace_array *tr) 4594 { 4595 struct ftrace_func_probe *probe, *n; 4596 4597 list_for_each_entry_safe(probe, n, &tr->func_probes, list) 4598 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops); 4599 } 4600 4601 static LIST_HEAD(ftrace_commands); 4602 static DEFINE_MUTEX(ftrace_cmd_mutex); 4603 4604 /* 4605 * Currently we only register ftrace commands from __init, so mark this 4606 * __init too. 4607 */ 4608 __init int register_ftrace_command(struct ftrace_func_command *cmd) 4609 { 4610 struct ftrace_func_command *p; 4611 int ret = 0; 4612 4613 mutex_lock(&ftrace_cmd_mutex); 4614 list_for_each_entry(p, &ftrace_commands, list) { 4615 if (strcmp(cmd->name, p->name) == 0) { 4616 ret = -EBUSY; 4617 goto out_unlock; 4618 } 4619 } 4620 list_add(&cmd->list, &ftrace_commands); 4621 out_unlock: 4622 mutex_unlock(&ftrace_cmd_mutex); 4623 4624 return ret; 4625 } 4626 4627 /* 4628 * Currently we only unregister ftrace commands from __init, so mark 4629 * this __init too. 4630 */ 4631 __init int unregister_ftrace_command(struct ftrace_func_command *cmd) 4632 { 4633 struct ftrace_func_command *p, *n; 4634 int ret = -ENODEV; 4635 4636 mutex_lock(&ftrace_cmd_mutex); 4637 list_for_each_entry_safe(p, n, &ftrace_commands, list) { 4638 if (strcmp(cmd->name, p->name) == 0) { 4639 ret = 0; 4640 list_del_init(&p->list); 4641 goto out_unlock; 4642 } 4643 } 4644 out_unlock: 4645 mutex_unlock(&ftrace_cmd_mutex); 4646 4647 return ret; 4648 } 4649 4650 static int ftrace_process_regex(struct ftrace_iterator *iter, 4651 char *buff, int len, int enable) 4652 { 4653 struct ftrace_hash *hash = iter->hash; 4654 struct trace_array *tr = iter->ops->private; 4655 char *func, *command, *next = buff; 4656 struct ftrace_func_command *p; 4657 int ret = -EINVAL; 4658 4659 func = strsep(&next, ":"); 4660 4661 if (!next) { 4662 ret = ftrace_match_records(hash, func, len); 4663 if (!ret) 4664 ret = -EINVAL; 4665 if (ret < 0) 4666 return ret; 4667 return 0; 4668 } 4669 4670 /* command found */ 4671 4672 command = strsep(&next, ":"); 4673 4674 mutex_lock(&ftrace_cmd_mutex); 4675 list_for_each_entry(p, &ftrace_commands, list) { 4676 if (strcmp(p->name, command) == 0) { 4677 ret = p->func(tr, hash, func, command, next, enable); 4678 goto out_unlock; 4679 } 4680 } 4681 out_unlock: 4682 mutex_unlock(&ftrace_cmd_mutex); 4683 4684 return ret; 4685 } 4686 4687 static ssize_t 4688 ftrace_regex_write(struct file *file, const char __user *ubuf, 4689 size_t cnt, loff_t *ppos, int enable) 4690 { 4691 struct ftrace_iterator *iter; 4692 struct trace_parser *parser; 4693 ssize_t ret, read; 4694 4695 if (!cnt) 4696 return 0; 4697 4698 if (file->f_mode & FMODE_READ) { 4699 struct seq_file *m = file->private_data; 4700 iter = m->private; 4701 } else 4702 iter = file->private_data; 4703 4704 if (unlikely(ftrace_disabled)) 4705 return -ENODEV; 4706 4707 /* iter->hash is a local copy, so we don't need regex_lock */ 4708 4709 parser = &iter->parser; 4710 read = trace_get_user(parser, ubuf, cnt, ppos); 4711 4712 if (read >= 0 && trace_parser_loaded(parser) && 4713 !trace_parser_cont(parser)) { 4714 ret = ftrace_process_regex(iter, parser->buffer, 4715 parser->idx, enable); 4716 trace_parser_clear(parser); 4717 if (ret < 0) 4718 goto out; 4719 } 4720 4721 ret = read; 4722 out: 4723 return ret; 4724 } 4725 4726 ssize_t 4727 ftrace_filter_write(struct file *file, const char __user *ubuf, 4728 size_t cnt, loff_t *ppos) 4729 { 4730 return ftrace_regex_write(file, ubuf, cnt, ppos, 1); 4731 } 4732 4733 ssize_t 4734 ftrace_notrace_write(struct file *file, const char __user *ubuf, 4735 size_t cnt, loff_t *ppos) 4736 { 4737 return ftrace_regex_write(file, ubuf, cnt, ppos, 0); 4738 } 4739 4740 static int 4741 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove) 4742 { 4743 struct ftrace_func_entry *entry; 4744 4745 if (!ftrace_location(ip)) 4746 return -EINVAL; 4747 4748 if (remove) { 4749 entry = ftrace_lookup_ip(hash, ip); 4750 if (!entry) 4751 return -ENOENT; 4752 free_hash_entry(hash, entry); 4753 return 0; 4754 } 4755 4756 return add_hash_entry(hash, ip); 4757 } 4758 4759 static int 4760 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len, 4761 unsigned long ip, int remove, int reset, int enable) 4762 { 4763 struct ftrace_hash **orig_hash; 4764 struct ftrace_hash *hash; 4765 int ret; 4766 4767 if (unlikely(ftrace_disabled)) 4768 return -ENODEV; 4769 4770 mutex_lock(&ops->func_hash->regex_lock); 4771 4772 if (enable) 4773 orig_hash = &ops->func_hash->filter_hash; 4774 else 4775 orig_hash = &ops->func_hash->notrace_hash; 4776 4777 if (reset) 4778 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); 4779 else 4780 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); 4781 4782 if (!hash) { 4783 ret = -ENOMEM; 4784 goto out_regex_unlock; 4785 } 4786 4787 if (buf && !ftrace_match_records(hash, buf, len)) { 4788 ret = -EINVAL; 4789 goto out_regex_unlock; 4790 } 4791 if (ip) { 4792 ret = ftrace_match_addr(hash, ip, remove); 4793 if (ret < 0) 4794 goto out_regex_unlock; 4795 } 4796 4797 mutex_lock(&ftrace_lock); 4798 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable); 4799 mutex_unlock(&ftrace_lock); 4800 4801 out_regex_unlock: 4802 mutex_unlock(&ops->func_hash->regex_lock); 4803 4804 free_ftrace_hash(hash); 4805 return ret; 4806 } 4807 4808 static int 4809 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove, 4810 int reset, int enable) 4811 { 4812 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable); 4813 } 4814 4815 /** 4816 * ftrace_set_filter_ip - set a function to filter on in ftrace by address 4817 * @ops - the ops to set the filter with 4818 * @ip - the address to add to or remove from the filter. 4819 * @remove - non zero to remove the ip from the filter 4820 * @reset - non zero to reset all filters before applying this filter. 4821 * 4822 * Filters denote which functions should be enabled when tracing is enabled 4823 * If @ip is NULL, it failes to update filter. 4824 */ 4825 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, 4826 int remove, int reset) 4827 { 4828 ftrace_ops_init(ops); 4829 return ftrace_set_addr(ops, ip, remove, reset, 1); 4830 } 4831 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip); 4832 4833 /** 4834 * ftrace_ops_set_global_filter - setup ops to use global filters 4835 * @ops - the ops which will use the global filters 4836 * 4837 * ftrace users who need global function trace filtering should call this. 4838 * It can set the global filter only if ops were not initialized before. 4839 */ 4840 void ftrace_ops_set_global_filter(struct ftrace_ops *ops) 4841 { 4842 if (ops->flags & FTRACE_OPS_FL_INITIALIZED) 4843 return; 4844 4845 ftrace_ops_init(ops); 4846 ops->func_hash = &global_ops.local_hash; 4847 } 4848 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter); 4849 4850 static int 4851 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, 4852 int reset, int enable) 4853 { 4854 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable); 4855 } 4856 4857 /** 4858 * ftrace_set_filter - set a function to filter on in ftrace 4859 * @ops - the ops to set the filter with 4860 * @buf - the string that holds the function filter text. 4861 * @len - the length of the string. 4862 * @reset - non zero to reset all filters before applying this filter. 4863 * 4864 * Filters denote which functions should be enabled when tracing is enabled. 4865 * If @buf is NULL and reset is set, all functions will be enabled for tracing. 4866 */ 4867 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, 4868 int len, int reset) 4869 { 4870 ftrace_ops_init(ops); 4871 return ftrace_set_regex(ops, buf, len, reset, 1); 4872 } 4873 EXPORT_SYMBOL_GPL(ftrace_set_filter); 4874 4875 /** 4876 * ftrace_set_notrace - set a function to not trace in ftrace 4877 * @ops - the ops to set the notrace filter with 4878 * @buf - the string that holds the function notrace text. 4879 * @len - the length of the string. 4880 * @reset - non zero to reset all filters before applying this filter. 4881 * 4882 * Notrace Filters denote which functions should not be enabled when tracing 4883 * is enabled. If @buf is NULL and reset is set, all functions will be enabled 4884 * for tracing. 4885 */ 4886 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, 4887 int len, int reset) 4888 { 4889 ftrace_ops_init(ops); 4890 return ftrace_set_regex(ops, buf, len, reset, 0); 4891 } 4892 EXPORT_SYMBOL_GPL(ftrace_set_notrace); 4893 /** 4894 * ftrace_set_global_filter - set a function to filter on with global tracers 4895 * @buf - the string that holds the function filter text. 4896 * @len - the length of the string. 4897 * @reset - non zero to reset all filters before applying this filter. 4898 * 4899 * Filters denote which functions should be enabled when tracing is enabled. 4900 * If @buf is NULL and reset is set, all functions will be enabled for tracing. 4901 */ 4902 void ftrace_set_global_filter(unsigned char *buf, int len, int reset) 4903 { 4904 ftrace_set_regex(&global_ops, buf, len, reset, 1); 4905 } 4906 EXPORT_SYMBOL_GPL(ftrace_set_global_filter); 4907 4908 /** 4909 * ftrace_set_global_notrace - set a function to not trace with global tracers 4910 * @buf - the string that holds the function notrace text. 4911 * @len - the length of the string. 4912 * @reset - non zero to reset all filters before applying this filter. 4913 * 4914 * Notrace Filters denote which functions should not be enabled when tracing 4915 * is enabled. If @buf is NULL and reset is set, all functions will be enabled 4916 * for tracing. 4917 */ 4918 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset) 4919 { 4920 ftrace_set_regex(&global_ops, buf, len, reset, 0); 4921 } 4922 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace); 4923 4924 /* 4925 * command line interface to allow users to set filters on boot up. 4926 */ 4927 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE 4928 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata; 4929 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata; 4930 4931 /* Used by function selftest to not test if filter is set */ 4932 bool ftrace_filter_param __initdata; 4933 4934 static int __init set_ftrace_notrace(char *str) 4935 { 4936 ftrace_filter_param = true; 4937 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE); 4938 return 1; 4939 } 4940 __setup("ftrace_notrace=", set_ftrace_notrace); 4941 4942 static int __init set_ftrace_filter(char *str) 4943 { 4944 ftrace_filter_param = true; 4945 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE); 4946 return 1; 4947 } 4948 __setup("ftrace_filter=", set_ftrace_filter); 4949 4950 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 4951 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; 4952 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata; 4953 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer); 4954 4955 static unsigned long save_global_trampoline; 4956 static unsigned long save_global_flags; 4957 4958 static int __init set_graph_function(char *str) 4959 { 4960 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); 4961 return 1; 4962 } 4963 __setup("ftrace_graph_filter=", set_graph_function); 4964 4965 static int __init set_graph_notrace_function(char *str) 4966 { 4967 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE); 4968 return 1; 4969 } 4970 __setup("ftrace_graph_notrace=", set_graph_notrace_function); 4971 4972 static int __init set_graph_max_depth_function(char *str) 4973 { 4974 if (!str) 4975 return 0; 4976 fgraph_max_depth = simple_strtoul(str, NULL, 0); 4977 return 1; 4978 } 4979 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function); 4980 4981 static void __init set_ftrace_early_graph(char *buf, int enable) 4982 { 4983 int ret; 4984 char *func; 4985 struct ftrace_hash *hash; 4986 4987 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); 4988 if (WARN_ON(!hash)) 4989 return; 4990 4991 while (buf) { 4992 func = strsep(&buf, ","); 4993 /* we allow only one expression at a time */ 4994 ret = ftrace_graph_set_hash(hash, func); 4995 if (ret) 4996 printk(KERN_DEBUG "ftrace: function %s not " 4997 "traceable\n", func); 4998 } 4999 5000 if (enable) 5001 ftrace_graph_hash = hash; 5002 else 5003 ftrace_graph_notrace_hash = hash; 5004 } 5005 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 5006 5007 void __init 5008 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable) 5009 { 5010 char *func; 5011 5012 ftrace_ops_init(ops); 5013 5014 while (buf) { 5015 func = strsep(&buf, ","); 5016 ftrace_set_regex(ops, func, strlen(func), 0, enable); 5017 } 5018 } 5019 5020 static void __init set_ftrace_early_filters(void) 5021 { 5022 if (ftrace_filter_buf[0]) 5023 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1); 5024 if (ftrace_notrace_buf[0]) 5025 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0); 5026 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 5027 if (ftrace_graph_buf[0]) 5028 set_ftrace_early_graph(ftrace_graph_buf, 1); 5029 if (ftrace_graph_notrace_buf[0]) 5030 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0); 5031 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 5032 } 5033 5034 int ftrace_regex_release(struct inode *inode, struct file *file) 5035 { 5036 struct seq_file *m = (struct seq_file *)file->private_data; 5037 struct ftrace_iterator *iter; 5038 struct ftrace_hash **orig_hash; 5039 struct trace_parser *parser; 5040 int filter_hash; 5041 int ret; 5042 5043 if (file->f_mode & FMODE_READ) { 5044 iter = m->private; 5045 seq_release(inode, file); 5046 } else 5047 iter = file->private_data; 5048 5049 parser = &iter->parser; 5050 if (trace_parser_loaded(parser)) { 5051 parser->buffer[parser->idx] = 0; 5052 ftrace_match_records(iter->hash, parser->buffer, parser->idx); 5053 } 5054 5055 trace_parser_put(parser); 5056 5057 mutex_lock(&iter->ops->func_hash->regex_lock); 5058 5059 if (file->f_mode & FMODE_WRITE) { 5060 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER); 5061 5062 if (filter_hash) { 5063 orig_hash = &iter->ops->func_hash->filter_hash; 5064 if (iter->tr && !list_empty(&iter->tr->mod_trace)) 5065 iter->hash->flags |= FTRACE_HASH_FL_MOD; 5066 } else 5067 orig_hash = &iter->ops->func_hash->notrace_hash; 5068 5069 mutex_lock(&ftrace_lock); 5070 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash, 5071 iter->hash, filter_hash); 5072 mutex_unlock(&ftrace_lock); 5073 } else { 5074 /* For read only, the hash is the ops hash */ 5075 iter->hash = NULL; 5076 } 5077 5078 mutex_unlock(&iter->ops->func_hash->regex_lock); 5079 free_ftrace_hash(iter->hash); 5080 kfree(iter); 5081 5082 return 0; 5083 } 5084 5085 static const struct file_operations ftrace_avail_fops = { 5086 .open = ftrace_avail_open, 5087 .read = seq_read, 5088 .llseek = seq_lseek, 5089 .release = seq_release_private, 5090 }; 5091 5092 static const struct file_operations ftrace_enabled_fops = { 5093 .open = ftrace_enabled_open, 5094 .read = seq_read, 5095 .llseek = seq_lseek, 5096 .release = seq_release_private, 5097 }; 5098 5099 static const struct file_operations ftrace_filter_fops = { 5100 .open = ftrace_filter_open, 5101 .read = seq_read, 5102 .write = ftrace_filter_write, 5103 .llseek = tracing_lseek, 5104 .release = ftrace_regex_release, 5105 }; 5106 5107 static const struct file_operations ftrace_notrace_fops = { 5108 .open = ftrace_notrace_open, 5109 .read = seq_read, 5110 .write = ftrace_notrace_write, 5111 .llseek = tracing_lseek, 5112 .release = ftrace_regex_release, 5113 }; 5114 5115 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 5116 5117 static DEFINE_MUTEX(graph_lock); 5118 5119 struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH; 5120 struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH; 5121 5122 enum graph_filter_type { 5123 GRAPH_FILTER_NOTRACE = 0, 5124 GRAPH_FILTER_FUNCTION, 5125 }; 5126 5127 #define FTRACE_GRAPH_EMPTY ((void *)1) 5128 5129 struct ftrace_graph_data { 5130 struct ftrace_hash *hash; 5131 struct ftrace_func_entry *entry; 5132 int idx; /* for hash table iteration */ 5133 enum graph_filter_type type; 5134 struct ftrace_hash *new_hash; 5135 const struct seq_operations *seq_ops; 5136 struct trace_parser parser; 5137 }; 5138 5139 static void * 5140 __g_next(struct seq_file *m, loff_t *pos) 5141 { 5142 struct ftrace_graph_data *fgd = m->private; 5143 struct ftrace_func_entry *entry = fgd->entry; 5144 struct hlist_head *head; 5145 int i, idx = fgd->idx; 5146 5147 if (*pos >= fgd->hash->count) 5148 return NULL; 5149 5150 if (entry) { 5151 hlist_for_each_entry_continue(entry, hlist) { 5152 fgd->entry = entry; 5153 return entry; 5154 } 5155 5156 idx++; 5157 } 5158 5159 for (i = idx; i < 1 << fgd->hash->size_bits; i++) { 5160 head = &fgd->hash->buckets[i]; 5161 hlist_for_each_entry(entry, head, hlist) { 5162 fgd->entry = entry; 5163 fgd->idx = i; 5164 return entry; 5165 } 5166 } 5167 return NULL; 5168 } 5169 5170 static void * 5171 g_next(struct seq_file *m, void *v, loff_t *pos) 5172 { 5173 (*pos)++; 5174 return __g_next(m, pos); 5175 } 5176 5177 static void *g_start(struct seq_file *m, loff_t *pos) 5178 { 5179 struct ftrace_graph_data *fgd = m->private; 5180 5181 mutex_lock(&graph_lock); 5182 5183 if (fgd->type == GRAPH_FILTER_FUNCTION) 5184 fgd->hash = rcu_dereference_protected(ftrace_graph_hash, 5185 lockdep_is_held(&graph_lock)); 5186 else 5187 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash, 5188 lockdep_is_held(&graph_lock)); 5189 5190 /* Nothing, tell g_show to print all functions are enabled */ 5191 if (ftrace_hash_empty(fgd->hash) && !*pos) 5192 return FTRACE_GRAPH_EMPTY; 5193 5194 fgd->idx = 0; 5195 fgd->entry = NULL; 5196 return __g_next(m, pos); 5197 } 5198 5199 static void g_stop(struct seq_file *m, void *p) 5200 { 5201 mutex_unlock(&graph_lock); 5202 } 5203 5204 static int g_show(struct seq_file *m, void *v) 5205 { 5206 struct ftrace_func_entry *entry = v; 5207 5208 if (!entry) 5209 return 0; 5210 5211 if (entry == FTRACE_GRAPH_EMPTY) { 5212 struct ftrace_graph_data *fgd = m->private; 5213 5214 if (fgd->type == GRAPH_FILTER_FUNCTION) 5215 seq_puts(m, "#### all functions enabled ####\n"); 5216 else 5217 seq_puts(m, "#### no functions disabled ####\n"); 5218 return 0; 5219 } 5220 5221 seq_printf(m, "%ps\n", (void *)entry->ip); 5222 5223 return 0; 5224 } 5225 5226 static const struct seq_operations ftrace_graph_seq_ops = { 5227 .start = g_start, 5228 .next = g_next, 5229 .stop = g_stop, 5230 .show = g_show, 5231 }; 5232 5233 static int 5234 __ftrace_graph_open(struct inode *inode, struct file *file, 5235 struct ftrace_graph_data *fgd) 5236 { 5237 int ret = 0; 5238 struct ftrace_hash *new_hash = NULL; 5239 5240 if (file->f_mode & FMODE_WRITE) { 5241 const int size_bits = FTRACE_HASH_DEFAULT_BITS; 5242 5243 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX)) 5244 return -ENOMEM; 5245 5246 if (file->f_flags & O_TRUNC) 5247 new_hash = alloc_ftrace_hash(size_bits); 5248 else 5249 new_hash = alloc_and_copy_ftrace_hash(size_bits, 5250 fgd->hash); 5251 if (!new_hash) { 5252 ret = -ENOMEM; 5253 goto out; 5254 } 5255 } 5256 5257 if (file->f_mode & FMODE_READ) { 5258 ret = seq_open(file, &ftrace_graph_seq_ops); 5259 if (!ret) { 5260 struct seq_file *m = file->private_data; 5261 m->private = fgd; 5262 } else { 5263 /* Failed */ 5264 free_ftrace_hash(new_hash); 5265 new_hash = NULL; 5266 } 5267 } else 5268 file->private_data = fgd; 5269 5270 out: 5271 if (ret < 0 && file->f_mode & FMODE_WRITE) 5272 trace_parser_put(&fgd->parser); 5273 5274 fgd->new_hash = new_hash; 5275 5276 /* 5277 * All uses of fgd->hash must be taken with the graph_lock 5278 * held. The graph_lock is going to be released, so force 5279 * fgd->hash to be reinitialized when it is taken again. 5280 */ 5281 fgd->hash = NULL; 5282 5283 return ret; 5284 } 5285 5286 static int 5287 ftrace_graph_open(struct inode *inode, struct file *file) 5288 { 5289 struct ftrace_graph_data *fgd; 5290 int ret; 5291 5292 if (unlikely(ftrace_disabled)) 5293 return -ENODEV; 5294 5295 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL); 5296 if (fgd == NULL) 5297 return -ENOMEM; 5298 5299 mutex_lock(&graph_lock); 5300 5301 fgd->hash = rcu_dereference_protected(ftrace_graph_hash, 5302 lockdep_is_held(&graph_lock)); 5303 fgd->type = GRAPH_FILTER_FUNCTION; 5304 fgd->seq_ops = &ftrace_graph_seq_ops; 5305 5306 ret = __ftrace_graph_open(inode, file, fgd); 5307 if (ret < 0) 5308 kfree(fgd); 5309 5310 mutex_unlock(&graph_lock); 5311 return ret; 5312 } 5313 5314 static int 5315 ftrace_graph_notrace_open(struct inode *inode, struct file *file) 5316 { 5317 struct ftrace_graph_data *fgd; 5318 int ret; 5319 5320 if (unlikely(ftrace_disabled)) 5321 return -ENODEV; 5322 5323 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL); 5324 if (fgd == NULL) 5325 return -ENOMEM; 5326 5327 mutex_lock(&graph_lock); 5328 5329 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash, 5330 lockdep_is_held(&graph_lock)); 5331 fgd->type = GRAPH_FILTER_NOTRACE; 5332 fgd->seq_ops = &ftrace_graph_seq_ops; 5333 5334 ret = __ftrace_graph_open(inode, file, fgd); 5335 if (ret < 0) 5336 kfree(fgd); 5337 5338 mutex_unlock(&graph_lock); 5339 return ret; 5340 } 5341 5342 static int 5343 ftrace_graph_release(struct inode *inode, struct file *file) 5344 { 5345 struct ftrace_graph_data *fgd; 5346 struct ftrace_hash *old_hash, *new_hash; 5347 struct trace_parser *parser; 5348 int ret = 0; 5349 5350 if (file->f_mode & FMODE_READ) { 5351 struct seq_file *m = file->private_data; 5352 5353 fgd = m->private; 5354 seq_release(inode, file); 5355 } else { 5356 fgd = file->private_data; 5357 } 5358 5359 5360 if (file->f_mode & FMODE_WRITE) { 5361 5362 parser = &fgd->parser; 5363 5364 if (trace_parser_loaded((parser))) { 5365 parser->buffer[parser->idx] = 0; 5366 ret = ftrace_graph_set_hash(fgd->new_hash, 5367 parser->buffer); 5368 } 5369 5370 trace_parser_put(parser); 5371 5372 new_hash = __ftrace_hash_move(fgd->new_hash); 5373 if (!new_hash) { 5374 ret = -ENOMEM; 5375 goto out; 5376 } 5377 5378 mutex_lock(&graph_lock); 5379 5380 if (fgd->type == GRAPH_FILTER_FUNCTION) { 5381 old_hash = rcu_dereference_protected(ftrace_graph_hash, 5382 lockdep_is_held(&graph_lock)); 5383 rcu_assign_pointer(ftrace_graph_hash, new_hash); 5384 } else { 5385 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash, 5386 lockdep_is_held(&graph_lock)); 5387 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash); 5388 } 5389 5390 mutex_unlock(&graph_lock); 5391 5392 /* Wait till all users are no longer using the old hash */ 5393 synchronize_sched(); 5394 5395 free_ftrace_hash(old_hash); 5396 } 5397 5398 out: 5399 free_ftrace_hash(fgd->new_hash); 5400 kfree(fgd); 5401 5402 return ret; 5403 } 5404 5405 static int 5406 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer) 5407 { 5408 struct ftrace_glob func_g; 5409 struct dyn_ftrace *rec; 5410 struct ftrace_page *pg; 5411 struct ftrace_func_entry *entry; 5412 int fail = 1; 5413 int not; 5414 5415 /* decode regex */ 5416 func_g.type = filter_parse_regex(buffer, strlen(buffer), 5417 &func_g.search, ¬); 5418 5419 func_g.len = strlen(func_g.search); 5420 5421 mutex_lock(&ftrace_lock); 5422 5423 if (unlikely(ftrace_disabled)) { 5424 mutex_unlock(&ftrace_lock); 5425 return -ENODEV; 5426 } 5427 5428 do_for_each_ftrace_rec(pg, rec) { 5429 5430 if (rec->flags & FTRACE_FL_DISABLED) 5431 continue; 5432 5433 if (ftrace_match_record(rec, &func_g, NULL, 0)) { 5434 entry = ftrace_lookup_ip(hash, rec->ip); 5435 5436 if (!not) { 5437 fail = 0; 5438 5439 if (entry) 5440 continue; 5441 if (add_hash_entry(hash, rec->ip) < 0) 5442 goto out; 5443 } else { 5444 if (entry) { 5445 free_hash_entry(hash, entry); 5446 fail = 0; 5447 } 5448 } 5449 } 5450 } while_for_each_ftrace_rec(); 5451 out: 5452 mutex_unlock(&ftrace_lock); 5453 5454 if (fail) 5455 return -EINVAL; 5456 5457 return 0; 5458 } 5459 5460 static ssize_t 5461 ftrace_graph_write(struct file *file, const char __user *ubuf, 5462 size_t cnt, loff_t *ppos) 5463 { 5464 ssize_t read, ret = 0; 5465 struct ftrace_graph_data *fgd = file->private_data; 5466 struct trace_parser *parser; 5467 5468 if (!cnt) 5469 return 0; 5470 5471 /* Read mode uses seq functions */ 5472 if (file->f_mode & FMODE_READ) { 5473 struct seq_file *m = file->private_data; 5474 fgd = m->private; 5475 } 5476 5477 parser = &fgd->parser; 5478 5479 read = trace_get_user(parser, ubuf, cnt, ppos); 5480 5481 if (read >= 0 && trace_parser_loaded(parser) && 5482 !trace_parser_cont(parser)) { 5483 5484 ret = ftrace_graph_set_hash(fgd->new_hash, 5485 parser->buffer); 5486 trace_parser_clear(parser); 5487 } 5488 5489 if (!ret) 5490 ret = read; 5491 5492 return ret; 5493 } 5494 5495 static const struct file_operations ftrace_graph_fops = { 5496 .open = ftrace_graph_open, 5497 .read = seq_read, 5498 .write = ftrace_graph_write, 5499 .llseek = tracing_lseek, 5500 .release = ftrace_graph_release, 5501 }; 5502 5503 static const struct file_operations ftrace_graph_notrace_fops = { 5504 .open = ftrace_graph_notrace_open, 5505 .read = seq_read, 5506 .write = ftrace_graph_write, 5507 .llseek = tracing_lseek, 5508 .release = ftrace_graph_release, 5509 }; 5510 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 5511 5512 void ftrace_create_filter_files(struct ftrace_ops *ops, 5513 struct dentry *parent) 5514 { 5515 5516 trace_create_file("set_ftrace_filter", 0644, parent, 5517 ops, &ftrace_filter_fops); 5518 5519 trace_create_file("set_ftrace_notrace", 0644, parent, 5520 ops, &ftrace_notrace_fops); 5521 } 5522 5523 /* 5524 * The name "destroy_filter_files" is really a misnomer. Although 5525 * in the future, it may actualy delete the files, but this is 5526 * really intended to make sure the ops passed in are disabled 5527 * and that when this function returns, the caller is free to 5528 * free the ops. 5529 * 5530 * The "destroy" name is only to match the "create" name that this 5531 * should be paired with. 5532 */ 5533 void ftrace_destroy_filter_files(struct ftrace_ops *ops) 5534 { 5535 mutex_lock(&ftrace_lock); 5536 if (ops->flags & FTRACE_OPS_FL_ENABLED) 5537 ftrace_shutdown(ops, 0); 5538 ops->flags |= FTRACE_OPS_FL_DELETED; 5539 mutex_unlock(&ftrace_lock); 5540 } 5541 5542 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer) 5543 { 5544 5545 trace_create_file("available_filter_functions", 0444, 5546 d_tracer, NULL, &ftrace_avail_fops); 5547 5548 trace_create_file("enabled_functions", 0444, 5549 d_tracer, NULL, &ftrace_enabled_fops); 5550 5551 ftrace_create_filter_files(&global_ops, d_tracer); 5552 5553 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 5554 trace_create_file("set_graph_function", 0444, d_tracer, 5555 NULL, 5556 &ftrace_graph_fops); 5557 trace_create_file("set_graph_notrace", 0444, d_tracer, 5558 NULL, 5559 &ftrace_graph_notrace_fops); 5560 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 5561 5562 return 0; 5563 } 5564 5565 static int ftrace_cmp_ips(const void *a, const void *b) 5566 { 5567 const unsigned long *ipa = a; 5568 const unsigned long *ipb = b; 5569 5570 if (*ipa > *ipb) 5571 return 1; 5572 if (*ipa < *ipb) 5573 return -1; 5574 return 0; 5575 } 5576 5577 static int ftrace_process_locs(struct module *mod, 5578 unsigned long *start, 5579 unsigned long *end) 5580 { 5581 struct ftrace_page *start_pg; 5582 struct ftrace_page *pg; 5583 struct dyn_ftrace *rec; 5584 unsigned long count; 5585 unsigned long *p; 5586 unsigned long addr; 5587 unsigned long flags = 0; /* Shut up gcc */ 5588 int ret = -ENOMEM; 5589 5590 count = end - start; 5591 5592 if (!count) 5593 return 0; 5594 5595 sort(start, count, sizeof(*start), 5596 ftrace_cmp_ips, NULL); 5597 5598 start_pg = ftrace_allocate_pages(count); 5599 if (!start_pg) 5600 return -ENOMEM; 5601 5602 mutex_lock(&ftrace_lock); 5603 5604 /* 5605 * Core and each module needs their own pages, as 5606 * modules will free them when they are removed. 5607 * Force a new page to be allocated for modules. 5608 */ 5609 if (!mod) { 5610 WARN_ON(ftrace_pages || ftrace_pages_start); 5611 /* First initialization */ 5612 ftrace_pages = ftrace_pages_start = start_pg; 5613 } else { 5614 if (!ftrace_pages) 5615 goto out; 5616 5617 if (WARN_ON(ftrace_pages->next)) { 5618 /* Hmm, we have free pages? */ 5619 while (ftrace_pages->next) 5620 ftrace_pages = ftrace_pages->next; 5621 } 5622 5623 ftrace_pages->next = start_pg; 5624 } 5625 5626 p = start; 5627 pg = start_pg; 5628 while (p < end) { 5629 addr = ftrace_call_adjust(*p++); 5630 /* 5631 * Some architecture linkers will pad between 5632 * the different mcount_loc sections of different 5633 * object files to satisfy alignments. 5634 * Skip any NULL pointers. 5635 */ 5636 if (!addr) 5637 continue; 5638 5639 if (pg->index == pg->size) { 5640 /* We should have allocated enough */ 5641 if (WARN_ON(!pg->next)) 5642 break; 5643 pg = pg->next; 5644 } 5645 5646 rec = &pg->records[pg->index++]; 5647 rec->ip = addr; 5648 } 5649 5650 /* We should have used all pages */ 5651 WARN_ON(pg->next); 5652 5653 /* Assign the last page to ftrace_pages */ 5654 ftrace_pages = pg; 5655 5656 /* 5657 * We only need to disable interrupts on start up 5658 * because we are modifying code that an interrupt 5659 * may execute, and the modification is not atomic. 5660 * But for modules, nothing runs the code we modify 5661 * until we are finished with it, and there's no 5662 * reason to cause large interrupt latencies while we do it. 5663 */ 5664 if (!mod) 5665 local_irq_save(flags); 5666 ftrace_update_code(mod, start_pg); 5667 if (!mod) 5668 local_irq_restore(flags); 5669 ret = 0; 5670 out: 5671 mutex_unlock(&ftrace_lock); 5672 5673 return ret; 5674 } 5675 5676 #ifdef CONFIG_MODULES 5677 5678 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next) 5679 5680 static int referenced_filters(struct dyn_ftrace *rec) 5681 { 5682 struct ftrace_ops *ops; 5683 int cnt = 0; 5684 5685 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) { 5686 if (ops_references_rec(ops, rec)) 5687 cnt++; 5688 } 5689 5690 return cnt; 5691 } 5692 5693 void ftrace_release_mod(struct module *mod) 5694 { 5695 struct dyn_ftrace *rec; 5696 struct ftrace_page **last_pg; 5697 struct ftrace_page *pg; 5698 int order; 5699 5700 mutex_lock(&ftrace_lock); 5701 5702 if (ftrace_disabled) 5703 goto out_unlock; 5704 5705 /* 5706 * Each module has its own ftrace_pages, remove 5707 * them from the list. 5708 */ 5709 last_pg = &ftrace_pages_start; 5710 for (pg = ftrace_pages_start; pg; pg = *last_pg) { 5711 rec = &pg->records[0]; 5712 if (within_module_core(rec->ip, mod)) { 5713 /* 5714 * As core pages are first, the first 5715 * page should never be a module page. 5716 */ 5717 if (WARN_ON(pg == ftrace_pages_start)) 5718 goto out_unlock; 5719 5720 /* Check if we are deleting the last page */ 5721 if (pg == ftrace_pages) 5722 ftrace_pages = next_to_ftrace_page(last_pg); 5723 5724 ftrace_update_tot_cnt -= pg->index; 5725 *last_pg = pg->next; 5726 order = get_count_order(pg->size / ENTRIES_PER_PAGE); 5727 free_pages((unsigned long)pg->records, order); 5728 kfree(pg); 5729 } else 5730 last_pg = &pg->next; 5731 } 5732 out_unlock: 5733 mutex_unlock(&ftrace_lock); 5734 } 5735 5736 void ftrace_module_enable(struct module *mod) 5737 { 5738 struct dyn_ftrace *rec; 5739 struct ftrace_page *pg; 5740 5741 mutex_lock(&ftrace_lock); 5742 5743 if (ftrace_disabled) 5744 goto out_unlock; 5745 5746 /* 5747 * If the tracing is enabled, go ahead and enable the record. 5748 * 5749 * The reason not to enable the record immediatelly is the 5750 * inherent check of ftrace_make_nop/ftrace_make_call for 5751 * correct previous instructions. Making first the NOP 5752 * conversion puts the module to the correct state, thus 5753 * passing the ftrace_make_call check. 5754 * 5755 * We also delay this to after the module code already set the 5756 * text to read-only, as we now need to set it back to read-write 5757 * so that we can modify the text. 5758 */ 5759 if (ftrace_start_up) 5760 ftrace_arch_code_modify_prepare(); 5761 5762 do_for_each_ftrace_rec(pg, rec) { 5763 int cnt; 5764 /* 5765 * do_for_each_ftrace_rec() is a double loop. 5766 * module text shares the pg. If a record is 5767 * not part of this module, then skip this pg, 5768 * which the "break" will do. 5769 */ 5770 if (!within_module_core(rec->ip, mod)) 5771 break; 5772 5773 cnt = 0; 5774 5775 /* 5776 * When adding a module, we need to check if tracers are 5777 * currently enabled and if they are, and can trace this record, 5778 * we need to enable the module functions as well as update the 5779 * reference counts for those function records. 5780 */ 5781 if (ftrace_start_up) 5782 cnt += referenced_filters(rec); 5783 5784 /* This clears FTRACE_FL_DISABLED */ 5785 rec->flags = cnt; 5786 5787 if (ftrace_start_up && cnt) { 5788 int failed = __ftrace_replace_code(rec, 1); 5789 if (failed) { 5790 ftrace_bug(failed, rec); 5791 goto out_loop; 5792 } 5793 } 5794 5795 } while_for_each_ftrace_rec(); 5796 5797 out_loop: 5798 if (ftrace_start_up) 5799 ftrace_arch_code_modify_post_process(); 5800 5801 out_unlock: 5802 mutex_unlock(&ftrace_lock); 5803 5804 process_cached_mods(mod->name); 5805 } 5806 5807 void ftrace_module_init(struct module *mod) 5808 { 5809 if (ftrace_disabled || !mod->num_ftrace_callsites) 5810 return; 5811 5812 ftrace_process_locs(mod, mod->ftrace_callsites, 5813 mod->ftrace_callsites + mod->num_ftrace_callsites); 5814 } 5815 #endif /* CONFIG_MODULES */ 5816 5817 void __init ftrace_free_init_mem(void) 5818 { 5819 unsigned long start = (unsigned long)(&__init_begin); 5820 unsigned long end = (unsigned long)(&__init_end); 5821 struct ftrace_page **last_pg = &ftrace_pages_start; 5822 struct ftrace_page *pg; 5823 struct dyn_ftrace *rec; 5824 struct dyn_ftrace key; 5825 int order; 5826 5827 key.ip = start; 5828 key.flags = end; /* overload flags, as it is unsigned long */ 5829 5830 mutex_lock(&ftrace_lock); 5831 5832 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) { 5833 if (end < pg->records[0].ip || 5834 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE)) 5835 continue; 5836 again: 5837 rec = bsearch(&key, pg->records, pg->index, 5838 sizeof(struct dyn_ftrace), 5839 ftrace_cmp_recs); 5840 if (!rec) 5841 continue; 5842 pg->index--; 5843 ftrace_update_tot_cnt--; 5844 if (!pg->index) { 5845 *last_pg = pg->next; 5846 order = get_count_order(pg->size / ENTRIES_PER_PAGE); 5847 free_pages((unsigned long)pg->records, order); 5848 kfree(pg); 5849 pg = container_of(last_pg, struct ftrace_page, next); 5850 if (!(*last_pg)) 5851 ftrace_pages = pg; 5852 continue; 5853 } 5854 memmove(rec, rec + 1, 5855 (pg->index - (rec - pg->records)) * sizeof(*rec)); 5856 /* More than one function may be in this block */ 5857 goto again; 5858 } 5859 mutex_unlock(&ftrace_lock); 5860 } 5861 5862 void __init ftrace_init(void) 5863 { 5864 extern unsigned long __start_mcount_loc[]; 5865 extern unsigned long __stop_mcount_loc[]; 5866 unsigned long count, flags; 5867 int ret; 5868 5869 local_irq_save(flags); 5870 ret = ftrace_dyn_arch_init(); 5871 local_irq_restore(flags); 5872 if (ret) 5873 goto failed; 5874 5875 count = __stop_mcount_loc - __start_mcount_loc; 5876 if (!count) { 5877 pr_info("ftrace: No functions to be traced?\n"); 5878 goto failed; 5879 } 5880 5881 pr_info("ftrace: allocating %ld entries in %ld pages\n", 5882 count, count / ENTRIES_PER_PAGE + 1); 5883 5884 last_ftrace_enabled = ftrace_enabled = 1; 5885 5886 ret = ftrace_process_locs(NULL, 5887 __start_mcount_loc, 5888 __stop_mcount_loc); 5889 5890 set_ftrace_early_filters(); 5891 5892 return; 5893 failed: 5894 ftrace_disabled = 1; 5895 } 5896 5897 /* Do nothing if arch does not support this */ 5898 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops) 5899 { 5900 } 5901 5902 static void ftrace_update_trampoline(struct ftrace_ops *ops) 5903 { 5904 arch_ftrace_update_trampoline(ops); 5905 } 5906 5907 void ftrace_init_trace_array(struct trace_array *tr) 5908 { 5909 INIT_LIST_HEAD(&tr->func_probes); 5910 INIT_LIST_HEAD(&tr->mod_trace); 5911 INIT_LIST_HEAD(&tr->mod_notrace); 5912 } 5913 #else 5914 5915 static struct ftrace_ops global_ops = { 5916 .func = ftrace_stub, 5917 .flags = FTRACE_OPS_FL_RECURSION_SAFE | 5918 FTRACE_OPS_FL_INITIALIZED | 5919 FTRACE_OPS_FL_PID, 5920 }; 5921 5922 static int __init ftrace_nodyn_init(void) 5923 { 5924 ftrace_enabled = 1; 5925 return 0; 5926 } 5927 core_initcall(ftrace_nodyn_init); 5928 5929 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; } 5930 static inline void ftrace_startup_enable(int command) { } 5931 static inline void ftrace_startup_all(int command) { } 5932 /* Keep as macros so we do not need to define the commands */ 5933 # define ftrace_startup(ops, command) \ 5934 ({ \ 5935 int ___ret = __register_ftrace_function(ops); \ 5936 if (!___ret) \ 5937 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \ 5938 ___ret; \ 5939 }) 5940 # define ftrace_shutdown(ops, command) \ 5941 ({ \ 5942 int ___ret = __unregister_ftrace_function(ops); \ 5943 if (!___ret) \ 5944 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \ 5945 ___ret; \ 5946 }) 5947 5948 # define ftrace_startup_sysctl() do { } while (0) 5949 # define ftrace_shutdown_sysctl() do { } while (0) 5950 5951 static inline int 5952 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) 5953 { 5954 return 1; 5955 } 5956 5957 static void ftrace_update_trampoline(struct ftrace_ops *ops) 5958 { 5959 } 5960 5961 #endif /* CONFIG_DYNAMIC_FTRACE */ 5962 5963 __init void ftrace_init_global_array_ops(struct trace_array *tr) 5964 { 5965 tr->ops = &global_ops; 5966 tr->ops->private = tr; 5967 ftrace_init_trace_array(tr); 5968 } 5969 5970 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func) 5971 { 5972 /* If we filter on pids, update to use the pid function */ 5973 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) { 5974 if (WARN_ON(tr->ops->func != ftrace_stub)) 5975 printk("ftrace ops had %pS for function\n", 5976 tr->ops->func); 5977 } 5978 tr->ops->func = func; 5979 tr->ops->private = tr; 5980 } 5981 5982 void ftrace_reset_array_ops(struct trace_array *tr) 5983 { 5984 tr->ops->func = ftrace_stub; 5985 } 5986 5987 static inline void 5988 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, 5989 struct ftrace_ops *ignored, struct pt_regs *regs) 5990 { 5991 struct ftrace_ops *op; 5992 int bit; 5993 5994 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); 5995 if (bit < 0) 5996 return; 5997 5998 /* 5999 * Some of the ops may be dynamically allocated, 6000 * they must be freed after a synchronize_sched(). 6001 */ 6002 preempt_disable_notrace(); 6003 6004 do_for_each_ftrace_op(op, ftrace_ops_list) { 6005 /* 6006 * Check the following for each ops before calling their func: 6007 * if RCU flag is set, then rcu_is_watching() must be true 6008 * if PER_CPU is set, then ftrace_function_local_disable() 6009 * must be false 6010 * Otherwise test if the ip matches the ops filter 6011 * 6012 * If any of the above fails then the op->func() is not executed. 6013 */ 6014 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) && 6015 (!(op->flags & FTRACE_OPS_FL_PER_CPU) || 6016 !ftrace_function_local_disabled(op)) && 6017 ftrace_ops_test(op, ip, regs)) { 6018 6019 if (FTRACE_WARN_ON(!op->func)) { 6020 pr_warn("op=%p %pS\n", op, op); 6021 goto out; 6022 } 6023 op->func(ip, parent_ip, op, regs); 6024 } 6025 } while_for_each_ftrace_op(op); 6026 out: 6027 preempt_enable_notrace(); 6028 trace_clear_recursion(bit); 6029 } 6030 6031 /* 6032 * Some archs only support passing ip and parent_ip. Even though 6033 * the list function ignores the op parameter, we do not want any 6034 * C side effects, where a function is called without the caller 6035 * sending a third parameter. 6036 * Archs are to support both the regs and ftrace_ops at the same time. 6037 * If they support ftrace_ops, it is assumed they support regs. 6038 * If call backs want to use regs, they must either check for regs 6039 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS. 6040 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved. 6041 * An architecture can pass partial regs with ftrace_ops and still 6042 * set the ARCH_SUPPORTS_FTRACE_OPS. 6043 */ 6044 #if ARCH_SUPPORTS_FTRACE_OPS 6045 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, 6046 struct ftrace_ops *op, struct pt_regs *regs) 6047 { 6048 __ftrace_ops_list_func(ip, parent_ip, NULL, regs); 6049 } 6050 #else 6051 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip) 6052 { 6053 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL); 6054 } 6055 #endif 6056 6057 /* 6058 * If there's only one function registered but it does not support 6059 * recursion, needs RCU protection and/or requires per cpu handling, then 6060 * this function will be called by the mcount trampoline. 6061 */ 6062 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip, 6063 struct ftrace_ops *op, struct pt_regs *regs) 6064 { 6065 int bit; 6066 6067 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching()) 6068 return; 6069 6070 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); 6071 if (bit < 0) 6072 return; 6073 6074 preempt_disable_notrace(); 6075 6076 if (!(op->flags & FTRACE_OPS_FL_PER_CPU) || 6077 !ftrace_function_local_disabled(op)) { 6078 op->func(ip, parent_ip, op, regs); 6079 } 6080 6081 preempt_enable_notrace(); 6082 trace_clear_recursion(bit); 6083 } 6084 6085 /** 6086 * ftrace_ops_get_func - get the function a trampoline should call 6087 * @ops: the ops to get the function for 6088 * 6089 * Normally the mcount trampoline will call the ops->func, but there 6090 * are times that it should not. For example, if the ops does not 6091 * have its own recursion protection, then it should call the 6092 * ftrace_ops_assist_func() instead. 6093 * 6094 * Returns the function that the trampoline should call for @ops. 6095 */ 6096 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops) 6097 { 6098 /* 6099 * If the function does not handle recursion, needs to be RCU safe, 6100 * or does per cpu logic, then we need to call the assist handler. 6101 */ 6102 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) || 6103 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU)) 6104 return ftrace_ops_assist_func; 6105 6106 return ops->func; 6107 } 6108 6109 static void 6110 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt, 6111 struct task_struct *prev, struct task_struct *next) 6112 { 6113 struct trace_array *tr = data; 6114 struct trace_pid_list *pid_list; 6115 6116 pid_list = rcu_dereference_sched(tr->function_pids); 6117 6118 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid, 6119 trace_ignore_this_task(pid_list, next)); 6120 } 6121 6122 static void 6123 ftrace_pid_follow_sched_process_fork(void *data, 6124 struct task_struct *self, 6125 struct task_struct *task) 6126 { 6127 struct trace_pid_list *pid_list; 6128 struct trace_array *tr = data; 6129 6130 pid_list = rcu_dereference_sched(tr->function_pids); 6131 trace_filter_add_remove_task(pid_list, self, task); 6132 } 6133 6134 static void 6135 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task) 6136 { 6137 struct trace_pid_list *pid_list; 6138 struct trace_array *tr = data; 6139 6140 pid_list = rcu_dereference_sched(tr->function_pids); 6141 trace_filter_add_remove_task(pid_list, NULL, task); 6142 } 6143 6144 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable) 6145 { 6146 if (enable) { 6147 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork, 6148 tr); 6149 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit, 6150 tr); 6151 } else { 6152 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork, 6153 tr); 6154 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit, 6155 tr); 6156 } 6157 } 6158 6159 static void clear_ftrace_pids(struct trace_array *tr) 6160 { 6161 struct trace_pid_list *pid_list; 6162 int cpu; 6163 6164 pid_list = rcu_dereference_protected(tr->function_pids, 6165 lockdep_is_held(&ftrace_lock)); 6166 if (!pid_list) 6167 return; 6168 6169 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr); 6170 6171 for_each_possible_cpu(cpu) 6172 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false; 6173 6174 rcu_assign_pointer(tr->function_pids, NULL); 6175 6176 /* Wait till all users are no longer using pid filtering */ 6177 synchronize_sched(); 6178 6179 trace_free_pid_list(pid_list); 6180 } 6181 6182 void ftrace_clear_pids(struct trace_array *tr) 6183 { 6184 mutex_lock(&ftrace_lock); 6185 6186 clear_ftrace_pids(tr); 6187 6188 mutex_unlock(&ftrace_lock); 6189 } 6190 6191 static void ftrace_pid_reset(struct trace_array *tr) 6192 { 6193 mutex_lock(&ftrace_lock); 6194 clear_ftrace_pids(tr); 6195 6196 ftrace_update_pid_func(); 6197 ftrace_startup_all(0); 6198 6199 mutex_unlock(&ftrace_lock); 6200 } 6201 6202 /* Greater than any max PID */ 6203 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1) 6204 6205 static void *fpid_start(struct seq_file *m, loff_t *pos) 6206 __acquires(RCU) 6207 { 6208 struct trace_pid_list *pid_list; 6209 struct trace_array *tr = m->private; 6210 6211 mutex_lock(&ftrace_lock); 6212 rcu_read_lock_sched(); 6213 6214 pid_list = rcu_dereference_sched(tr->function_pids); 6215 6216 if (!pid_list) 6217 return !(*pos) ? FTRACE_NO_PIDS : NULL; 6218 6219 return trace_pid_start(pid_list, pos); 6220 } 6221 6222 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos) 6223 { 6224 struct trace_array *tr = m->private; 6225 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids); 6226 6227 if (v == FTRACE_NO_PIDS) 6228 return NULL; 6229 6230 return trace_pid_next(pid_list, v, pos); 6231 } 6232 6233 static void fpid_stop(struct seq_file *m, void *p) 6234 __releases(RCU) 6235 { 6236 rcu_read_unlock_sched(); 6237 mutex_unlock(&ftrace_lock); 6238 } 6239 6240 static int fpid_show(struct seq_file *m, void *v) 6241 { 6242 if (v == FTRACE_NO_PIDS) { 6243 seq_puts(m, "no pid\n"); 6244 return 0; 6245 } 6246 6247 return trace_pid_show(m, v); 6248 } 6249 6250 static const struct seq_operations ftrace_pid_sops = { 6251 .start = fpid_start, 6252 .next = fpid_next, 6253 .stop = fpid_stop, 6254 .show = fpid_show, 6255 }; 6256 6257 static int 6258 ftrace_pid_open(struct inode *inode, struct file *file) 6259 { 6260 struct trace_array *tr = inode->i_private; 6261 struct seq_file *m; 6262 int ret = 0; 6263 6264 if (trace_array_get(tr) < 0) 6265 return -ENODEV; 6266 6267 if ((file->f_mode & FMODE_WRITE) && 6268 (file->f_flags & O_TRUNC)) 6269 ftrace_pid_reset(tr); 6270 6271 ret = seq_open(file, &ftrace_pid_sops); 6272 if (ret < 0) { 6273 trace_array_put(tr); 6274 } else { 6275 m = file->private_data; 6276 /* copy tr over to seq ops */ 6277 m->private = tr; 6278 } 6279 6280 return ret; 6281 } 6282 6283 static void ignore_task_cpu(void *data) 6284 { 6285 struct trace_array *tr = data; 6286 struct trace_pid_list *pid_list; 6287 6288 /* 6289 * This function is called by on_each_cpu() while the 6290 * event_mutex is held. 6291 */ 6292 pid_list = rcu_dereference_protected(tr->function_pids, 6293 mutex_is_locked(&ftrace_lock)); 6294 6295 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid, 6296 trace_ignore_this_task(pid_list, current)); 6297 } 6298 6299 static ssize_t 6300 ftrace_pid_write(struct file *filp, const char __user *ubuf, 6301 size_t cnt, loff_t *ppos) 6302 { 6303 struct seq_file *m = filp->private_data; 6304 struct trace_array *tr = m->private; 6305 struct trace_pid_list *filtered_pids = NULL; 6306 struct trace_pid_list *pid_list; 6307 ssize_t ret; 6308 6309 if (!cnt) 6310 return 0; 6311 6312 mutex_lock(&ftrace_lock); 6313 6314 filtered_pids = rcu_dereference_protected(tr->function_pids, 6315 lockdep_is_held(&ftrace_lock)); 6316 6317 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt); 6318 if (ret < 0) 6319 goto out; 6320 6321 rcu_assign_pointer(tr->function_pids, pid_list); 6322 6323 if (filtered_pids) { 6324 synchronize_sched(); 6325 trace_free_pid_list(filtered_pids); 6326 } else if (pid_list) { 6327 /* Register a probe to set whether to ignore the tracing of a task */ 6328 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr); 6329 } 6330 6331 /* 6332 * Ignoring of pids is done at task switch. But we have to 6333 * check for those tasks that are currently running. 6334 * Always do this in case a pid was appended or removed. 6335 */ 6336 on_each_cpu(ignore_task_cpu, tr, 1); 6337 6338 ftrace_update_pid_func(); 6339 ftrace_startup_all(0); 6340 out: 6341 mutex_unlock(&ftrace_lock); 6342 6343 if (ret > 0) 6344 *ppos += ret; 6345 6346 return ret; 6347 } 6348 6349 static int 6350 ftrace_pid_release(struct inode *inode, struct file *file) 6351 { 6352 struct trace_array *tr = inode->i_private; 6353 6354 trace_array_put(tr); 6355 6356 return seq_release(inode, file); 6357 } 6358 6359 static const struct file_operations ftrace_pid_fops = { 6360 .open = ftrace_pid_open, 6361 .write = ftrace_pid_write, 6362 .read = seq_read, 6363 .llseek = tracing_lseek, 6364 .release = ftrace_pid_release, 6365 }; 6366 6367 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer) 6368 { 6369 trace_create_file("set_ftrace_pid", 0644, d_tracer, 6370 tr, &ftrace_pid_fops); 6371 } 6372 6373 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr, 6374 struct dentry *d_tracer) 6375 { 6376 /* Only the top level directory has the dyn_tracefs and profile */ 6377 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL)); 6378 6379 ftrace_init_dyn_tracefs(d_tracer); 6380 ftrace_profile_tracefs(d_tracer); 6381 } 6382 6383 /** 6384 * ftrace_kill - kill ftrace 6385 * 6386 * This function should be used by panic code. It stops ftrace 6387 * but in a not so nice way. If you need to simply kill ftrace 6388 * from a non-atomic section, use ftrace_kill. 6389 */ 6390 void ftrace_kill(void) 6391 { 6392 ftrace_disabled = 1; 6393 ftrace_enabled = 0; 6394 clear_ftrace_function(); 6395 } 6396 6397 /** 6398 * Test if ftrace is dead or not. 6399 */ 6400 int ftrace_is_dead(void) 6401 { 6402 return ftrace_disabled; 6403 } 6404 6405 /** 6406 * register_ftrace_function - register a function for profiling 6407 * @ops - ops structure that holds the function for profiling. 6408 * 6409 * Register a function to be called by all functions in the 6410 * kernel. 6411 * 6412 * Note: @ops->func and all the functions it calls must be labeled 6413 * with "notrace", otherwise it will go into a 6414 * recursive loop. 6415 */ 6416 int register_ftrace_function(struct ftrace_ops *ops) 6417 { 6418 int ret = -1; 6419 6420 ftrace_ops_init(ops); 6421 6422 mutex_lock(&ftrace_lock); 6423 6424 ret = ftrace_startup(ops, 0); 6425 6426 mutex_unlock(&ftrace_lock); 6427 6428 return ret; 6429 } 6430 EXPORT_SYMBOL_GPL(register_ftrace_function); 6431 6432 /** 6433 * unregister_ftrace_function - unregister a function for profiling. 6434 * @ops - ops structure that holds the function to unregister 6435 * 6436 * Unregister a function that was added to be called by ftrace profiling. 6437 */ 6438 int unregister_ftrace_function(struct ftrace_ops *ops) 6439 { 6440 int ret; 6441 6442 mutex_lock(&ftrace_lock); 6443 ret = ftrace_shutdown(ops, 0); 6444 mutex_unlock(&ftrace_lock); 6445 6446 return ret; 6447 } 6448 EXPORT_SYMBOL_GPL(unregister_ftrace_function); 6449 6450 int 6451 ftrace_enable_sysctl(struct ctl_table *table, int write, 6452 void __user *buffer, size_t *lenp, 6453 loff_t *ppos) 6454 { 6455 int ret = -ENODEV; 6456 6457 mutex_lock(&ftrace_lock); 6458 6459 if (unlikely(ftrace_disabled)) 6460 goto out; 6461 6462 ret = proc_dointvec(table, write, buffer, lenp, ppos); 6463 6464 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) 6465 goto out; 6466 6467 last_ftrace_enabled = !!ftrace_enabled; 6468 6469 if (ftrace_enabled) { 6470 6471 /* we are starting ftrace again */ 6472 if (rcu_dereference_protected(ftrace_ops_list, 6473 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end) 6474 update_ftrace_function(); 6475 6476 ftrace_startup_sysctl(); 6477 6478 } else { 6479 /* stopping ftrace calls (just send to ftrace_stub) */ 6480 ftrace_trace_function = ftrace_stub; 6481 6482 ftrace_shutdown_sysctl(); 6483 } 6484 6485 out: 6486 mutex_unlock(&ftrace_lock); 6487 return ret; 6488 } 6489 6490 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 6491 6492 static struct ftrace_ops graph_ops = { 6493 .func = ftrace_stub, 6494 .flags = FTRACE_OPS_FL_RECURSION_SAFE | 6495 FTRACE_OPS_FL_INITIALIZED | 6496 FTRACE_OPS_FL_PID | 6497 FTRACE_OPS_FL_STUB, 6498 #ifdef FTRACE_GRAPH_TRAMP_ADDR 6499 .trampoline = FTRACE_GRAPH_TRAMP_ADDR, 6500 /* trampoline_size is only needed for dynamically allocated tramps */ 6501 #endif 6502 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash) 6503 }; 6504 6505 void ftrace_graph_sleep_time_control(bool enable) 6506 { 6507 fgraph_sleep_time = enable; 6508 } 6509 6510 void ftrace_graph_graph_time_control(bool enable) 6511 { 6512 fgraph_graph_time = enable; 6513 } 6514 6515 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace) 6516 { 6517 return 0; 6518 } 6519 6520 /* The callbacks that hook a function */ 6521 trace_func_graph_ret_t ftrace_graph_return = 6522 (trace_func_graph_ret_t)ftrace_stub; 6523 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub; 6524 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub; 6525 6526 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */ 6527 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) 6528 { 6529 int i; 6530 int ret = 0; 6531 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE; 6532 struct task_struct *g, *t; 6533 6534 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) { 6535 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH 6536 * sizeof(struct ftrace_ret_stack), 6537 GFP_KERNEL); 6538 if (!ret_stack_list[i]) { 6539 start = 0; 6540 end = i; 6541 ret = -ENOMEM; 6542 goto free; 6543 } 6544 } 6545 6546 read_lock(&tasklist_lock); 6547 do_each_thread(g, t) { 6548 if (start == end) { 6549 ret = -EAGAIN; 6550 goto unlock; 6551 } 6552 6553 if (t->ret_stack == NULL) { 6554 atomic_set(&t->tracing_graph_pause, 0); 6555 atomic_set(&t->trace_overrun, 0); 6556 t->curr_ret_stack = -1; 6557 /* Make sure the tasks see the -1 first: */ 6558 smp_wmb(); 6559 t->ret_stack = ret_stack_list[start++]; 6560 } 6561 } while_each_thread(g, t); 6562 6563 unlock: 6564 read_unlock(&tasklist_lock); 6565 free: 6566 for (i = start; i < end; i++) 6567 kfree(ret_stack_list[i]); 6568 return ret; 6569 } 6570 6571 static void 6572 ftrace_graph_probe_sched_switch(void *ignore, bool preempt, 6573 struct task_struct *prev, struct task_struct *next) 6574 { 6575 unsigned long long timestamp; 6576 int index; 6577 6578 /* 6579 * Does the user want to count the time a function was asleep. 6580 * If so, do not update the time stamps. 6581 */ 6582 if (fgraph_sleep_time) 6583 return; 6584 6585 timestamp = trace_clock_local(); 6586 6587 prev->ftrace_timestamp = timestamp; 6588 6589 /* only process tasks that we timestamped */ 6590 if (!next->ftrace_timestamp) 6591 return; 6592 6593 /* 6594 * Update all the counters in next to make up for the 6595 * time next was sleeping. 6596 */ 6597 timestamp -= next->ftrace_timestamp; 6598 6599 for (index = next->curr_ret_stack; index >= 0; index--) 6600 next->ret_stack[index].calltime += timestamp; 6601 } 6602 6603 /* Allocate a return stack for each task */ 6604 static int start_graph_tracing(void) 6605 { 6606 struct ftrace_ret_stack **ret_stack_list; 6607 int ret, cpu; 6608 6609 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE * 6610 sizeof(struct ftrace_ret_stack *), 6611 GFP_KERNEL); 6612 6613 if (!ret_stack_list) 6614 return -ENOMEM; 6615 6616 /* The cpu_boot init_task->ret_stack will never be freed */ 6617 for_each_online_cpu(cpu) { 6618 if (!idle_task(cpu)->ret_stack) 6619 ftrace_graph_init_idle_task(idle_task(cpu), cpu); 6620 } 6621 6622 do { 6623 ret = alloc_retstack_tasklist(ret_stack_list); 6624 } while (ret == -EAGAIN); 6625 6626 if (!ret) { 6627 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); 6628 if (ret) 6629 pr_info("ftrace_graph: Couldn't activate tracepoint" 6630 " probe to kernel_sched_switch\n"); 6631 } 6632 6633 kfree(ret_stack_list); 6634 return ret; 6635 } 6636 6637 /* 6638 * Hibernation protection. 6639 * The state of the current task is too much unstable during 6640 * suspend/restore to disk. We want to protect against that. 6641 */ 6642 static int 6643 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state, 6644 void *unused) 6645 { 6646 switch (state) { 6647 case PM_HIBERNATION_PREPARE: 6648 pause_graph_tracing(); 6649 break; 6650 6651 case PM_POST_HIBERNATION: 6652 unpause_graph_tracing(); 6653 break; 6654 } 6655 return NOTIFY_DONE; 6656 } 6657 6658 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace) 6659 { 6660 if (!ftrace_ops_test(&global_ops, trace->func, NULL)) 6661 return 0; 6662 return __ftrace_graph_entry(trace); 6663 } 6664 6665 /* 6666 * The function graph tracer should only trace the functions defined 6667 * by set_ftrace_filter and set_ftrace_notrace. If another function 6668 * tracer ops is registered, the graph tracer requires testing the 6669 * function against the global ops, and not just trace any function 6670 * that any ftrace_ops registered. 6671 */ 6672 static void update_function_graph_func(void) 6673 { 6674 struct ftrace_ops *op; 6675 bool do_test = false; 6676 6677 /* 6678 * The graph and global ops share the same set of functions 6679 * to test. If any other ops is on the list, then 6680 * the graph tracing needs to test if its the function 6681 * it should call. 6682 */ 6683 do_for_each_ftrace_op(op, ftrace_ops_list) { 6684 if (op != &global_ops && op != &graph_ops && 6685 op != &ftrace_list_end) { 6686 do_test = true; 6687 /* in double loop, break out with goto */ 6688 goto out; 6689 } 6690 } while_for_each_ftrace_op(op); 6691 out: 6692 if (do_test) 6693 ftrace_graph_entry = ftrace_graph_entry_test; 6694 else 6695 ftrace_graph_entry = __ftrace_graph_entry; 6696 } 6697 6698 static struct notifier_block ftrace_suspend_notifier = { 6699 .notifier_call = ftrace_suspend_notifier_call, 6700 }; 6701 6702 int register_ftrace_graph(trace_func_graph_ret_t retfunc, 6703 trace_func_graph_ent_t entryfunc) 6704 { 6705 int ret = 0; 6706 6707 mutex_lock(&ftrace_lock); 6708 6709 /* we currently allow only one tracer registered at a time */ 6710 if (ftrace_graph_active) { 6711 ret = -EBUSY; 6712 goto out; 6713 } 6714 6715 register_pm_notifier(&ftrace_suspend_notifier); 6716 6717 ftrace_graph_active++; 6718 ret = start_graph_tracing(); 6719 if (ret) { 6720 ftrace_graph_active--; 6721 goto out; 6722 } 6723 6724 ftrace_graph_return = retfunc; 6725 6726 /* 6727 * Update the indirect function to the entryfunc, and the 6728 * function that gets called to the entry_test first. Then 6729 * call the update fgraph entry function to determine if 6730 * the entryfunc should be called directly or not. 6731 */ 6732 __ftrace_graph_entry = entryfunc; 6733 ftrace_graph_entry = ftrace_graph_entry_test; 6734 update_function_graph_func(); 6735 6736 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET); 6737 out: 6738 mutex_unlock(&ftrace_lock); 6739 return ret; 6740 } 6741 6742 void unregister_ftrace_graph(void) 6743 { 6744 mutex_lock(&ftrace_lock); 6745 6746 if (unlikely(!ftrace_graph_active)) 6747 goto out; 6748 6749 ftrace_graph_active--; 6750 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub; 6751 ftrace_graph_entry = ftrace_graph_entry_stub; 6752 __ftrace_graph_entry = ftrace_graph_entry_stub; 6753 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET); 6754 unregister_pm_notifier(&ftrace_suspend_notifier); 6755 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); 6756 6757 #ifdef CONFIG_DYNAMIC_FTRACE 6758 /* 6759 * Function graph does not allocate the trampoline, but 6760 * other global_ops do. We need to reset the ALLOC_TRAMP flag 6761 * if one was used. 6762 */ 6763 global_ops.trampoline = save_global_trampoline; 6764 if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP) 6765 global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP; 6766 #endif 6767 6768 out: 6769 mutex_unlock(&ftrace_lock); 6770 } 6771 6772 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack); 6773 6774 static void 6775 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack) 6776 { 6777 atomic_set(&t->tracing_graph_pause, 0); 6778 atomic_set(&t->trace_overrun, 0); 6779 t->ftrace_timestamp = 0; 6780 /* make curr_ret_stack visible before we add the ret_stack */ 6781 smp_wmb(); 6782 t->ret_stack = ret_stack; 6783 } 6784 6785 /* 6786 * Allocate a return stack for the idle task. May be the first 6787 * time through, or it may be done by CPU hotplug online. 6788 */ 6789 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) 6790 { 6791 t->curr_ret_stack = -1; 6792 /* 6793 * The idle task has no parent, it either has its own 6794 * stack or no stack at all. 6795 */ 6796 if (t->ret_stack) 6797 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu)); 6798 6799 if (ftrace_graph_active) { 6800 struct ftrace_ret_stack *ret_stack; 6801 6802 ret_stack = per_cpu(idle_ret_stack, cpu); 6803 if (!ret_stack) { 6804 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH 6805 * sizeof(struct ftrace_ret_stack), 6806 GFP_KERNEL); 6807 if (!ret_stack) 6808 return; 6809 per_cpu(idle_ret_stack, cpu) = ret_stack; 6810 } 6811 graph_init_task(t, ret_stack); 6812 } 6813 } 6814 6815 /* Allocate a return stack for newly created task */ 6816 void ftrace_graph_init_task(struct task_struct *t) 6817 { 6818 /* Make sure we do not use the parent ret_stack */ 6819 t->ret_stack = NULL; 6820 t->curr_ret_stack = -1; 6821 6822 if (ftrace_graph_active) { 6823 struct ftrace_ret_stack *ret_stack; 6824 6825 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH 6826 * sizeof(struct ftrace_ret_stack), 6827 GFP_KERNEL); 6828 if (!ret_stack) 6829 return; 6830 graph_init_task(t, ret_stack); 6831 } 6832 } 6833 6834 void ftrace_graph_exit_task(struct task_struct *t) 6835 { 6836 struct ftrace_ret_stack *ret_stack = t->ret_stack; 6837 6838 t->ret_stack = NULL; 6839 /* NULL must become visible to IRQs before we free it: */ 6840 barrier(); 6841 6842 kfree(ret_stack); 6843 } 6844 #endif 6845