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 dynamic or per_cpu ops, they still 2832 * need their data 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_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) 2837 goto free_ops; 2838 2839 return 0; 2840 } 2841 2842 /* 2843 * If the ops uses a trampoline, then it needs to be 2844 * tested first on update. 2845 */ 2846 ops->flags |= FTRACE_OPS_FL_REMOVING; 2847 removed_ops = ops; 2848 2849 /* The trampoline logic checks the old hashes */ 2850 ops->old_hash.filter_hash = ops->func_hash->filter_hash; 2851 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash; 2852 2853 ftrace_run_update_code(command); 2854 2855 /* 2856 * If there's no more ops registered with ftrace, run a 2857 * sanity check to make sure all rec flags are cleared. 2858 */ 2859 if (rcu_dereference_protected(ftrace_ops_list, 2860 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) { 2861 struct ftrace_page *pg; 2862 struct dyn_ftrace *rec; 2863 2864 do_for_each_ftrace_rec(pg, rec) { 2865 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED)) 2866 pr_warn(" %pS flags:%lx\n", 2867 (void *)rec->ip, rec->flags); 2868 } while_for_each_ftrace_rec(); 2869 } 2870 2871 ops->old_hash.filter_hash = NULL; 2872 ops->old_hash.notrace_hash = NULL; 2873 2874 removed_ops = NULL; 2875 ops->flags &= ~FTRACE_OPS_FL_REMOVING; 2876 2877 /* 2878 * Dynamic ops may be freed, we must make sure that all 2879 * callers are done before leaving this function. 2880 * The same goes for freeing the per_cpu data of the per_cpu 2881 * ops. 2882 */ 2883 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) { 2884 /* 2885 * We need to do a hard force of sched synchronization. 2886 * This is because we use preempt_disable() to do RCU, but 2887 * the function tracers can be called where RCU is not watching 2888 * (like before user_exit()). We can not rely on the RCU 2889 * infrastructure to do the synchronization, thus we must do it 2890 * ourselves. 2891 */ 2892 schedule_on_each_cpu(ftrace_sync); 2893 2894 /* 2895 * When the kernel is preeptive, tasks can be preempted 2896 * while on a ftrace trampoline. Just scheduling a task on 2897 * a CPU is not good enough to flush them. Calling 2898 * synchornize_rcu_tasks() will wait for those tasks to 2899 * execute and either schedule voluntarily or enter user space. 2900 */ 2901 if (IS_ENABLED(CONFIG_PREEMPT)) 2902 synchronize_rcu_tasks(); 2903 2904 free_ops: 2905 arch_ftrace_trampoline_free(ops); 2906 2907 if (ops->flags & FTRACE_OPS_FL_PER_CPU) 2908 per_cpu_ops_free(ops); 2909 } 2910 2911 return 0; 2912 } 2913 2914 static void ftrace_startup_sysctl(void) 2915 { 2916 int command; 2917 2918 if (unlikely(ftrace_disabled)) 2919 return; 2920 2921 /* Force update next time */ 2922 saved_ftrace_func = NULL; 2923 /* ftrace_start_up is true if we want ftrace running */ 2924 if (ftrace_start_up) { 2925 command = FTRACE_UPDATE_CALLS; 2926 if (ftrace_graph_active) 2927 command |= FTRACE_START_FUNC_RET; 2928 ftrace_startup_enable(command); 2929 } 2930 } 2931 2932 static void ftrace_shutdown_sysctl(void) 2933 { 2934 int command; 2935 2936 if (unlikely(ftrace_disabled)) 2937 return; 2938 2939 /* ftrace_start_up is true if ftrace is running */ 2940 if (ftrace_start_up) { 2941 command = FTRACE_DISABLE_CALLS; 2942 if (ftrace_graph_active) 2943 command |= FTRACE_STOP_FUNC_RET; 2944 ftrace_run_update_code(command); 2945 } 2946 } 2947 2948 static u64 ftrace_update_time; 2949 unsigned long ftrace_update_tot_cnt; 2950 2951 static inline int ops_traces_mod(struct ftrace_ops *ops) 2952 { 2953 /* 2954 * Filter_hash being empty will default to trace module. 2955 * But notrace hash requires a test of individual module functions. 2956 */ 2957 return ftrace_hash_empty(ops->func_hash->filter_hash) && 2958 ftrace_hash_empty(ops->func_hash->notrace_hash); 2959 } 2960 2961 /* 2962 * Check if the current ops references the record. 2963 * 2964 * If the ops traces all functions, then it was already accounted for. 2965 * If the ops does not trace the current record function, skip it. 2966 * If the ops ignores the function via notrace filter, skip it. 2967 */ 2968 static inline bool 2969 ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec) 2970 { 2971 /* If ops isn't enabled, ignore it */ 2972 if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) 2973 return 0; 2974 2975 /* If ops traces all then it includes this function */ 2976 if (ops_traces_mod(ops)) 2977 return 1; 2978 2979 /* The function must be in the filter */ 2980 if (!ftrace_hash_empty(ops->func_hash->filter_hash) && 2981 !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip)) 2982 return 0; 2983 2984 /* If in notrace hash, we ignore it too */ 2985 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) 2986 return 0; 2987 2988 return 1; 2989 } 2990 2991 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs) 2992 { 2993 struct ftrace_page *pg; 2994 struct dyn_ftrace *p; 2995 u64 start, stop; 2996 unsigned long update_cnt = 0; 2997 unsigned long rec_flags = 0; 2998 int i; 2999 3000 start = ftrace_now(raw_smp_processor_id()); 3001 3002 /* 3003 * When a module is loaded, this function is called to convert 3004 * the calls to mcount in its text to nops, and also to create 3005 * an entry in the ftrace data. Now, if ftrace is activated 3006 * after this call, but before the module sets its text to 3007 * read-only, the modification of enabling ftrace can fail if 3008 * the read-only is done while ftrace is converting the calls. 3009 * To prevent this, the module's records are set as disabled 3010 * and will be enabled after the call to set the module's text 3011 * to read-only. 3012 */ 3013 if (mod) 3014 rec_flags |= FTRACE_FL_DISABLED; 3015 3016 for (pg = new_pgs; pg; pg = pg->next) { 3017 3018 for (i = 0; i < pg->index; i++) { 3019 3020 /* If something went wrong, bail without enabling anything */ 3021 if (unlikely(ftrace_disabled)) 3022 return -1; 3023 3024 p = &pg->records[i]; 3025 p->flags = rec_flags; 3026 3027 /* 3028 * Do the initial record conversion from mcount jump 3029 * to the NOP instructions. 3030 */ 3031 if (!ftrace_code_disable(mod, p)) 3032 break; 3033 3034 update_cnt++; 3035 } 3036 } 3037 3038 stop = ftrace_now(raw_smp_processor_id()); 3039 ftrace_update_time = stop - start; 3040 ftrace_update_tot_cnt += update_cnt; 3041 3042 return 0; 3043 } 3044 3045 static int ftrace_allocate_records(struct ftrace_page *pg, int count) 3046 { 3047 int order; 3048 int cnt; 3049 3050 if (WARN_ON(!count)) 3051 return -EINVAL; 3052 3053 order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE)); 3054 3055 /* 3056 * We want to fill as much as possible. No more than a page 3057 * may be empty. 3058 */ 3059 while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE) 3060 order--; 3061 3062 again: 3063 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order); 3064 3065 if (!pg->records) { 3066 /* if we can't allocate this size, try something smaller */ 3067 if (!order) 3068 return -ENOMEM; 3069 order >>= 1; 3070 goto again; 3071 } 3072 3073 cnt = (PAGE_SIZE << order) / ENTRY_SIZE; 3074 pg->size = cnt; 3075 3076 if (cnt > count) 3077 cnt = count; 3078 3079 return cnt; 3080 } 3081 3082 static struct ftrace_page * 3083 ftrace_allocate_pages(unsigned long num_to_init) 3084 { 3085 struct ftrace_page *start_pg; 3086 struct ftrace_page *pg; 3087 int order; 3088 int cnt; 3089 3090 if (!num_to_init) 3091 return 0; 3092 3093 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL); 3094 if (!pg) 3095 return NULL; 3096 3097 /* 3098 * Try to allocate as much as possible in one continues 3099 * location that fills in all of the space. We want to 3100 * waste as little space as possible. 3101 */ 3102 for (;;) { 3103 cnt = ftrace_allocate_records(pg, num_to_init); 3104 if (cnt < 0) 3105 goto free_pages; 3106 3107 num_to_init -= cnt; 3108 if (!num_to_init) 3109 break; 3110 3111 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL); 3112 if (!pg->next) 3113 goto free_pages; 3114 3115 pg = pg->next; 3116 } 3117 3118 return start_pg; 3119 3120 free_pages: 3121 pg = start_pg; 3122 while (pg) { 3123 order = get_count_order(pg->size / ENTRIES_PER_PAGE); 3124 free_pages((unsigned long)pg->records, order); 3125 start_pg = pg->next; 3126 kfree(pg); 3127 pg = start_pg; 3128 } 3129 pr_info("ftrace: FAILED to allocate memory for functions\n"); 3130 return NULL; 3131 } 3132 3133 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ 3134 3135 struct ftrace_iterator { 3136 loff_t pos; 3137 loff_t func_pos; 3138 loff_t mod_pos; 3139 struct ftrace_page *pg; 3140 struct dyn_ftrace *func; 3141 struct ftrace_func_probe *probe; 3142 struct ftrace_func_entry *probe_entry; 3143 struct trace_parser parser; 3144 struct ftrace_hash *hash; 3145 struct ftrace_ops *ops; 3146 struct trace_array *tr; 3147 struct list_head *mod_list; 3148 int pidx; 3149 int idx; 3150 unsigned flags; 3151 }; 3152 3153 static void * 3154 t_probe_next(struct seq_file *m, loff_t *pos) 3155 { 3156 struct ftrace_iterator *iter = m->private; 3157 struct trace_array *tr = iter->ops->private; 3158 struct list_head *func_probes; 3159 struct ftrace_hash *hash; 3160 struct list_head *next; 3161 struct hlist_node *hnd = NULL; 3162 struct hlist_head *hhd; 3163 int size; 3164 3165 (*pos)++; 3166 iter->pos = *pos; 3167 3168 if (!tr) 3169 return NULL; 3170 3171 func_probes = &tr->func_probes; 3172 if (list_empty(func_probes)) 3173 return NULL; 3174 3175 if (!iter->probe) { 3176 next = func_probes->next; 3177 iter->probe = list_entry(next, struct ftrace_func_probe, list); 3178 } 3179 3180 if (iter->probe_entry) 3181 hnd = &iter->probe_entry->hlist; 3182 3183 hash = iter->probe->ops.func_hash->filter_hash; 3184 size = 1 << hash->size_bits; 3185 3186 retry: 3187 if (iter->pidx >= size) { 3188 if (iter->probe->list.next == func_probes) 3189 return NULL; 3190 next = iter->probe->list.next; 3191 iter->probe = list_entry(next, struct ftrace_func_probe, list); 3192 hash = iter->probe->ops.func_hash->filter_hash; 3193 size = 1 << hash->size_bits; 3194 iter->pidx = 0; 3195 } 3196 3197 hhd = &hash->buckets[iter->pidx]; 3198 3199 if (hlist_empty(hhd)) { 3200 iter->pidx++; 3201 hnd = NULL; 3202 goto retry; 3203 } 3204 3205 if (!hnd) 3206 hnd = hhd->first; 3207 else { 3208 hnd = hnd->next; 3209 if (!hnd) { 3210 iter->pidx++; 3211 goto retry; 3212 } 3213 } 3214 3215 if (WARN_ON_ONCE(!hnd)) 3216 return NULL; 3217 3218 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist); 3219 3220 return iter; 3221 } 3222 3223 static void *t_probe_start(struct seq_file *m, loff_t *pos) 3224 { 3225 struct ftrace_iterator *iter = m->private; 3226 void *p = NULL; 3227 loff_t l; 3228 3229 if (!(iter->flags & FTRACE_ITER_DO_PROBES)) 3230 return NULL; 3231 3232 if (iter->mod_pos > *pos) 3233 return NULL; 3234 3235 iter->probe = NULL; 3236 iter->probe_entry = NULL; 3237 iter->pidx = 0; 3238 for (l = 0; l <= (*pos - iter->mod_pos); ) { 3239 p = t_probe_next(m, &l); 3240 if (!p) 3241 break; 3242 } 3243 if (!p) 3244 return NULL; 3245 3246 /* Only set this if we have an item */ 3247 iter->flags |= FTRACE_ITER_PROBE; 3248 3249 return iter; 3250 } 3251 3252 static int 3253 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter) 3254 { 3255 struct ftrace_func_entry *probe_entry; 3256 struct ftrace_probe_ops *probe_ops; 3257 struct ftrace_func_probe *probe; 3258 3259 probe = iter->probe; 3260 probe_entry = iter->probe_entry; 3261 3262 if (WARN_ON_ONCE(!probe || !probe_entry)) 3263 return -EIO; 3264 3265 probe_ops = probe->probe_ops; 3266 3267 if (probe_ops->print) 3268 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data); 3269 3270 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip, 3271 (void *)probe_ops->func); 3272 3273 return 0; 3274 } 3275 3276 static void * 3277 t_mod_next(struct seq_file *m, loff_t *pos) 3278 { 3279 struct ftrace_iterator *iter = m->private; 3280 struct trace_array *tr = iter->tr; 3281 3282 (*pos)++; 3283 iter->pos = *pos; 3284 3285 iter->mod_list = iter->mod_list->next; 3286 3287 if (iter->mod_list == &tr->mod_trace || 3288 iter->mod_list == &tr->mod_notrace) { 3289 iter->flags &= ~FTRACE_ITER_MOD; 3290 return NULL; 3291 } 3292 3293 iter->mod_pos = *pos; 3294 3295 return iter; 3296 } 3297 3298 static void *t_mod_start(struct seq_file *m, loff_t *pos) 3299 { 3300 struct ftrace_iterator *iter = m->private; 3301 void *p = NULL; 3302 loff_t l; 3303 3304 if (iter->func_pos > *pos) 3305 return NULL; 3306 3307 iter->mod_pos = iter->func_pos; 3308 3309 /* probes are only available if tr is set */ 3310 if (!iter->tr) 3311 return NULL; 3312 3313 for (l = 0; l <= (*pos - iter->func_pos); ) { 3314 p = t_mod_next(m, &l); 3315 if (!p) 3316 break; 3317 } 3318 if (!p) { 3319 iter->flags &= ~FTRACE_ITER_MOD; 3320 return t_probe_start(m, pos); 3321 } 3322 3323 /* Only set this if we have an item */ 3324 iter->flags |= FTRACE_ITER_MOD; 3325 3326 return iter; 3327 } 3328 3329 static int 3330 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter) 3331 { 3332 struct ftrace_mod_load *ftrace_mod; 3333 struct trace_array *tr = iter->tr; 3334 3335 if (WARN_ON_ONCE(!iter->mod_list) || 3336 iter->mod_list == &tr->mod_trace || 3337 iter->mod_list == &tr->mod_notrace) 3338 return -EIO; 3339 3340 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list); 3341 3342 if (ftrace_mod->func) 3343 seq_printf(m, "%s", ftrace_mod->func); 3344 else 3345 seq_putc(m, '*'); 3346 3347 seq_printf(m, ":mod:%s\n", ftrace_mod->module); 3348 3349 return 0; 3350 } 3351 3352 static void * 3353 t_func_next(struct seq_file *m, loff_t *pos) 3354 { 3355 struct ftrace_iterator *iter = m->private; 3356 struct dyn_ftrace *rec = NULL; 3357 3358 (*pos)++; 3359 3360 retry: 3361 if (iter->idx >= iter->pg->index) { 3362 if (iter->pg->next) { 3363 iter->pg = iter->pg->next; 3364 iter->idx = 0; 3365 goto retry; 3366 } 3367 } else { 3368 rec = &iter->pg->records[iter->idx++]; 3369 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) && 3370 !ftrace_lookup_ip(iter->hash, rec->ip)) || 3371 3372 ((iter->flags & FTRACE_ITER_ENABLED) && 3373 !(rec->flags & FTRACE_FL_ENABLED))) { 3374 3375 rec = NULL; 3376 goto retry; 3377 } 3378 } 3379 3380 if (!rec) 3381 return NULL; 3382 3383 iter->pos = iter->func_pos = *pos; 3384 iter->func = rec; 3385 3386 return iter; 3387 } 3388 3389 static void * 3390 t_next(struct seq_file *m, void *v, loff_t *pos) 3391 { 3392 struct ftrace_iterator *iter = m->private; 3393 loff_t l = *pos; /* t_probe_start() must use original pos */ 3394 void *ret; 3395 3396 if (unlikely(ftrace_disabled)) 3397 return NULL; 3398 3399 if (iter->flags & FTRACE_ITER_PROBE) 3400 return t_probe_next(m, pos); 3401 3402 if (iter->flags & FTRACE_ITER_MOD) 3403 return t_mod_next(m, pos); 3404 3405 if (iter->flags & FTRACE_ITER_PRINTALL) { 3406 /* next must increment pos, and t_probe_start does not */ 3407 (*pos)++; 3408 return t_mod_start(m, &l); 3409 } 3410 3411 ret = t_func_next(m, pos); 3412 3413 if (!ret) 3414 return t_mod_start(m, &l); 3415 3416 return ret; 3417 } 3418 3419 static void reset_iter_read(struct ftrace_iterator *iter) 3420 { 3421 iter->pos = 0; 3422 iter->func_pos = 0; 3423 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD); 3424 } 3425 3426 static void *t_start(struct seq_file *m, loff_t *pos) 3427 { 3428 struct ftrace_iterator *iter = m->private; 3429 void *p = NULL; 3430 loff_t l; 3431 3432 mutex_lock(&ftrace_lock); 3433 3434 if (unlikely(ftrace_disabled)) 3435 return NULL; 3436 3437 /* 3438 * If an lseek was done, then reset and start from beginning. 3439 */ 3440 if (*pos < iter->pos) 3441 reset_iter_read(iter); 3442 3443 /* 3444 * For set_ftrace_filter reading, if we have the filter 3445 * off, we can short cut and just print out that all 3446 * functions are enabled. 3447 */ 3448 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) && 3449 ftrace_hash_empty(iter->hash)) { 3450 iter->func_pos = 1; /* Account for the message */ 3451 if (*pos > 0) 3452 return t_mod_start(m, pos); 3453 iter->flags |= FTRACE_ITER_PRINTALL; 3454 /* reset in case of seek/pread */ 3455 iter->flags &= ~FTRACE_ITER_PROBE; 3456 return iter; 3457 } 3458 3459 if (iter->flags & FTRACE_ITER_MOD) 3460 return t_mod_start(m, pos); 3461 3462 /* 3463 * Unfortunately, we need to restart at ftrace_pages_start 3464 * every time we let go of the ftrace_mutex. This is because 3465 * those pointers can change without the lock. 3466 */ 3467 iter->pg = ftrace_pages_start; 3468 iter->idx = 0; 3469 for (l = 0; l <= *pos; ) { 3470 p = t_func_next(m, &l); 3471 if (!p) 3472 break; 3473 } 3474 3475 if (!p) 3476 return t_mod_start(m, pos); 3477 3478 return iter; 3479 } 3480 3481 static void t_stop(struct seq_file *m, void *p) 3482 { 3483 mutex_unlock(&ftrace_lock); 3484 } 3485 3486 void * __weak 3487 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec) 3488 { 3489 return NULL; 3490 } 3491 3492 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops, 3493 struct dyn_ftrace *rec) 3494 { 3495 void *ptr; 3496 3497 ptr = arch_ftrace_trampoline_func(ops, rec); 3498 if (ptr) 3499 seq_printf(m, " ->%pS", ptr); 3500 } 3501 3502 static int t_show(struct seq_file *m, void *v) 3503 { 3504 struct ftrace_iterator *iter = m->private; 3505 struct dyn_ftrace *rec; 3506 3507 if (iter->flags & FTRACE_ITER_PROBE) 3508 return t_probe_show(m, iter); 3509 3510 if (iter->flags & FTRACE_ITER_MOD) 3511 return t_mod_show(m, iter); 3512 3513 if (iter->flags & FTRACE_ITER_PRINTALL) { 3514 if (iter->flags & FTRACE_ITER_NOTRACE) 3515 seq_puts(m, "#### no functions disabled ####\n"); 3516 else 3517 seq_puts(m, "#### all functions enabled ####\n"); 3518 return 0; 3519 } 3520 3521 rec = iter->func; 3522 3523 if (!rec) 3524 return 0; 3525 3526 seq_printf(m, "%ps", (void *)rec->ip); 3527 if (iter->flags & FTRACE_ITER_ENABLED) { 3528 struct ftrace_ops *ops; 3529 3530 seq_printf(m, " (%ld)%s%s", 3531 ftrace_rec_count(rec), 3532 rec->flags & FTRACE_FL_REGS ? " R" : " ", 3533 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " "); 3534 if (rec->flags & FTRACE_FL_TRAMP_EN) { 3535 ops = ftrace_find_tramp_ops_any(rec); 3536 if (ops) { 3537 do { 3538 seq_printf(m, "\ttramp: %pS (%pS)", 3539 (void *)ops->trampoline, 3540 (void *)ops->func); 3541 add_trampoline_func(m, ops, rec); 3542 ops = ftrace_find_tramp_ops_next(rec, ops); 3543 } while (ops); 3544 } else 3545 seq_puts(m, "\ttramp: ERROR!"); 3546 } else { 3547 add_trampoline_func(m, NULL, rec); 3548 } 3549 } 3550 3551 seq_putc(m, '\n'); 3552 3553 return 0; 3554 } 3555 3556 static const struct seq_operations show_ftrace_seq_ops = { 3557 .start = t_start, 3558 .next = t_next, 3559 .stop = t_stop, 3560 .show = t_show, 3561 }; 3562 3563 static int 3564 ftrace_avail_open(struct inode *inode, struct file *file) 3565 { 3566 struct ftrace_iterator *iter; 3567 3568 if (unlikely(ftrace_disabled)) 3569 return -ENODEV; 3570 3571 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); 3572 if (!iter) 3573 return -ENOMEM; 3574 3575 iter->pg = ftrace_pages_start; 3576 iter->ops = &global_ops; 3577 3578 return 0; 3579 } 3580 3581 static int 3582 ftrace_enabled_open(struct inode *inode, struct file *file) 3583 { 3584 struct ftrace_iterator *iter; 3585 3586 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); 3587 if (!iter) 3588 return -ENOMEM; 3589 3590 iter->pg = ftrace_pages_start; 3591 iter->flags = FTRACE_ITER_ENABLED; 3592 iter->ops = &global_ops; 3593 3594 return 0; 3595 } 3596 3597 /** 3598 * ftrace_regex_open - initialize function tracer filter files 3599 * @ops: The ftrace_ops that hold the hash filters 3600 * @flag: The type of filter to process 3601 * @inode: The inode, usually passed in to your open routine 3602 * @file: The file, usually passed in to your open routine 3603 * 3604 * ftrace_regex_open() initializes the filter files for the 3605 * @ops. Depending on @flag it may process the filter hash or 3606 * the notrace hash of @ops. With this called from the open 3607 * routine, you can use ftrace_filter_write() for the write 3608 * routine if @flag has FTRACE_ITER_FILTER set, or 3609 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set. 3610 * tracing_lseek() should be used as the lseek routine, and 3611 * release must call ftrace_regex_release(). 3612 */ 3613 int 3614 ftrace_regex_open(struct ftrace_ops *ops, int flag, 3615 struct inode *inode, struct file *file) 3616 { 3617 struct ftrace_iterator *iter; 3618 struct ftrace_hash *hash; 3619 struct list_head *mod_head; 3620 struct trace_array *tr = ops->private; 3621 int ret = 0; 3622 3623 ftrace_ops_init(ops); 3624 3625 if (unlikely(ftrace_disabled)) 3626 return -ENODEV; 3627 3628 iter = kzalloc(sizeof(*iter), GFP_KERNEL); 3629 if (!iter) 3630 return -ENOMEM; 3631 3632 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) { 3633 kfree(iter); 3634 return -ENOMEM; 3635 } 3636 3637 iter->ops = ops; 3638 iter->flags = flag; 3639 iter->tr = tr; 3640 3641 mutex_lock(&ops->func_hash->regex_lock); 3642 3643 if (flag & FTRACE_ITER_NOTRACE) { 3644 hash = ops->func_hash->notrace_hash; 3645 mod_head = tr ? &tr->mod_notrace : NULL; 3646 } else { 3647 hash = ops->func_hash->filter_hash; 3648 mod_head = tr ? &tr->mod_trace : NULL; 3649 } 3650 3651 iter->mod_list = mod_head; 3652 3653 if (file->f_mode & FMODE_WRITE) { 3654 const int size_bits = FTRACE_HASH_DEFAULT_BITS; 3655 3656 if (file->f_flags & O_TRUNC) { 3657 iter->hash = alloc_ftrace_hash(size_bits); 3658 clear_ftrace_mod_list(mod_head); 3659 } else { 3660 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash); 3661 } 3662 3663 if (!iter->hash) { 3664 trace_parser_put(&iter->parser); 3665 kfree(iter); 3666 ret = -ENOMEM; 3667 goto out_unlock; 3668 } 3669 } else 3670 iter->hash = hash; 3671 3672 if (file->f_mode & FMODE_READ) { 3673 iter->pg = ftrace_pages_start; 3674 3675 ret = seq_open(file, &show_ftrace_seq_ops); 3676 if (!ret) { 3677 struct seq_file *m = file->private_data; 3678 m->private = iter; 3679 } else { 3680 /* Failed */ 3681 free_ftrace_hash(iter->hash); 3682 trace_parser_put(&iter->parser); 3683 kfree(iter); 3684 } 3685 } else 3686 file->private_data = iter; 3687 3688 out_unlock: 3689 mutex_unlock(&ops->func_hash->regex_lock); 3690 3691 return ret; 3692 } 3693 3694 static int 3695 ftrace_filter_open(struct inode *inode, struct file *file) 3696 { 3697 struct ftrace_ops *ops = inode->i_private; 3698 3699 return ftrace_regex_open(ops, 3700 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES, 3701 inode, file); 3702 } 3703 3704 static int 3705 ftrace_notrace_open(struct inode *inode, struct file *file) 3706 { 3707 struct ftrace_ops *ops = inode->i_private; 3708 3709 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE, 3710 inode, file); 3711 } 3712 3713 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */ 3714 struct ftrace_glob { 3715 char *search; 3716 unsigned len; 3717 int type; 3718 }; 3719 3720 /* 3721 * If symbols in an architecture don't correspond exactly to the user-visible 3722 * name of what they represent, it is possible to define this function to 3723 * perform the necessary adjustments. 3724 */ 3725 char * __weak arch_ftrace_match_adjust(char *str, const char *search) 3726 { 3727 return str; 3728 } 3729 3730 static int ftrace_match(char *str, struct ftrace_glob *g) 3731 { 3732 int matched = 0; 3733 int slen; 3734 3735 str = arch_ftrace_match_adjust(str, g->search); 3736 3737 switch (g->type) { 3738 case MATCH_FULL: 3739 if (strcmp(str, g->search) == 0) 3740 matched = 1; 3741 break; 3742 case MATCH_FRONT_ONLY: 3743 if (strncmp(str, g->search, g->len) == 0) 3744 matched = 1; 3745 break; 3746 case MATCH_MIDDLE_ONLY: 3747 if (strstr(str, g->search)) 3748 matched = 1; 3749 break; 3750 case MATCH_END_ONLY: 3751 slen = strlen(str); 3752 if (slen >= g->len && 3753 memcmp(str + slen - g->len, g->search, g->len) == 0) 3754 matched = 1; 3755 break; 3756 case MATCH_GLOB: 3757 if (glob_match(g->search, str)) 3758 matched = 1; 3759 break; 3760 } 3761 3762 return matched; 3763 } 3764 3765 static int 3766 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter) 3767 { 3768 struct ftrace_func_entry *entry; 3769 int ret = 0; 3770 3771 entry = ftrace_lookup_ip(hash, rec->ip); 3772 if (clear_filter) { 3773 /* Do nothing if it doesn't exist */ 3774 if (!entry) 3775 return 0; 3776 3777 free_hash_entry(hash, entry); 3778 } else { 3779 /* Do nothing if it exists */ 3780 if (entry) 3781 return 0; 3782 3783 ret = add_hash_entry(hash, rec->ip); 3784 } 3785 return ret; 3786 } 3787 3788 static int 3789 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g, 3790 struct ftrace_glob *mod_g, int exclude_mod) 3791 { 3792 char str[KSYM_SYMBOL_LEN]; 3793 char *modname; 3794 3795 kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); 3796 3797 if (mod_g) { 3798 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0; 3799 3800 /* blank module name to match all modules */ 3801 if (!mod_g->len) { 3802 /* blank module globbing: modname xor exclude_mod */ 3803 if (!exclude_mod != !modname) 3804 goto func_match; 3805 return 0; 3806 } 3807 3808 /* 3809 * exclude_mod is set to trace everything but the given 3810 * module. If it is set and the module matches, then 3811 * return 0. If it is not set, and the module doesn't match 3812 * also return 0. Otherwise, check the function to see if 3813 * that matches. 3814 */ 3815 if (!mod_matches == !exclude_mod) 3816 return 0; 3817 func_match: 3818 /* blank search means to match all funcs in the mod */ 3819 if (!func_g->len) 3820 return 1; 3821 } 3822 3823 return ftrace_match(str, func_g); 3824 } 3825 3826 static int 3827 match_records(struct ftrace_hash *hash, char *func, int len, char *mod) 3828 { 3829 struct ftrace_page *pg; 3830 struct dyn_ftrace *rec; 3831 struct ftrace_glob func_g = { .type = MATCH_FULL }; 3832 struct ftrace_glob mod_g = { .type = MATCH_FULL }; 3833 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL; 3834 int exclude_mod = 0; 3835 int found = 0; 3836 int ret; 3837 int clear_filter = 0; 3838 3839 if (func) { 3840 func_g.type = filter_parse_regex(func, len, &func_g.search, 3841 &clear_filter); 3842 func_g.len = strlen(func_g.search); 3843 } 3844 3845 if (mod) { 3846 mod_g.type = filter_parse_regex(mod, strlen(mod), 3847 &mod_g.search, &exclude_mod); 3848 mod_g.len = strlen(mod_g.search); 3849 } 3850 3851 mutex_lock(&ftrace_lock); 3852 3853 if (unlikely(ftrace_disabled)) 3854 goto out_unlock; 3855 3856 do_for_each_ftrace_rec(pg, rec) { 3857 3858 if (rec->flags & FTRACE_FL_DISABLED) 3859 continue; 3860 3861 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) { 3862 ret = enter_record(hash, rec, clear_filter); 3863 if (ret < 0) { 3864 found = ret; 3865 goto out_unlock; 3866 } 3867 found = 1; 3868 } 3869 } while_for_each_ftrace_rec(); 3870 out_unlock: 3871 mutex_unlock(&ftrace_lock); 3872 3873 return found; 3874 } 3875 3876 static int 3877 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len) 3878 { 3879 return match_records(hash, buff, len, NULL); 3880 } 3881 3882 static void ftrace_ops_update_code(struct ftrace_ops *ops, 3883 struct ftrace_ops_hash *old_hash) 3884 { 3885 struct ftrace_ops *op; 3886 3887 if (!ftrace_enabled) 3888 return; 3889 3890 if (ops->flags & FTRACE_OPS_FL_ENABLED) { 3891 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash); 3892 return; 3893 } 3894 3895 /* 3896 * If this is the shared global_ops filter, then we need to 3897 * check if there is another ops that shares it, is enabled. 3898 * If so, we still need to run the modify code. 3899 */ 3900 if (ops->func_hash != &global_ops.local_hash) 3901 return; 3902 3903 do_for_each_ftrace_op(op, ftrace_ops_list) { 3904 if (op->func_hash == &global_ops.local_hash && 3905 op->flags & FTRACE_OPS_FL_ENABLED) { 3906 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash); 3907 /* Only need to do this once */ 3908 return; 3909 } 3910 } while_for_each_ftrace_op(op); 3911 } 3912 3913 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops, 3914 struct ftrace_hash **orig_hash, 3915 struct ftrace_hash *hash, 3916 int enable) 3917 { 3918 struct ftrace_ops_hash old_hash_ops; 3919 struct ftrace_hash *old_hash; 3920 int ret; 3921 3922 old_hash = *orig_hash; 3923 old_hash_ops.filter_hash = ops->func_hash->filter_hash; 3924 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash; 3925 ret = ftrace_hash_move(ops, enable, orig_hash, hash); 3926 if (!ret) { 3927 ftrace_ops_update_code(ops, &old_hash_ops); 3928 free_ftrace_hash_rcu(old_hash); 3929 } 3930 return ret; 3931 } 3932 3933 static bool module_exists(const char *module) 3934 { 3935 /* All modules have the symbol __this_module */ 3936 const char this_mod[] = "__this_module"; 3937 const int modname_size = MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 1; 3938 char modname[modname_size + 1]; 3939 unsigned long val; 3940 int n; 3941 3942 n = snprintf(modname, modname_size + 1, "%s:%s", module, this_mod); 3943 3944 if (n > modname_size) 3945 return false; 3946 3947 val = module_kallsyms_lookup_name(modname); 3948 return val != 0; 3949 } 3950 3951 static int cache_mod(struct trace_array *tr, 3952 const char *func, char *module, int enable) 3953 { 3954 struct ftrace_mod_load *ftrace_mod, *n; 3955 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace; 3956 int ret; 3957 3958 mutex_lock(&ftrace_lock); 3959 3960 /* We do not cache inverse filters */ 3961 if (func[0] == '!') { 3962 func++; 3963 ret = -EINVAL; 3964 3965 /* Look to remove this hash */ 3966 list_for_each_entry_safe(ftrace_mod, n, head, list) { 3967 if (strcmp(ftrace_mod->module, module) != 0) 3968 continue; 3969 3970 /* no func matches all */ 3971 if (strcmp(func, "*") == 0 || 3972 (ftrace_mod->func && 3973 strcmp(ftrace_mod->func, func) == 0)) { 3974 ret = 0; 3975 free_ftrace_mod(ftrace_mod); 3976 continue; 3977 } 3978 } 3979 goto out; 3980 } 3981 3982 ret = -EINVAL; 3983 /* We only care about modules that have not been loaded yet */ 3984 if (module_exists(module)) 3985 goto out; 3986 3987 /* Save this string off, and execute it when the module is loaded */ 3988 ret = ftrace_add_mod(tr, func, module, enable); 3989 out: 3990 mutex_unlock(&ftrace_lock); 3991 3992 return ret; 3993 } 3994 3995 static int 3996 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, 3997 int reset, int enable); 3998 3999 #ifdef CONFIG_MODULES 4000 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops, 4001 char *mod, bool enable) 4002 { 4003 struct ftrace_mod_load *ftrace_mod, *n; 4004 struct ftrace_hash **orig_hash, *new_hash; 4005 LIST_HEAD(process_mods); 4006 char *func; 4007 int ret; 4008 4009 mutex_lock(&ops->func_hash->regex_lock); 4010 4011 if (enable) 4012 orig_hash = &ops->func_hash->filter_hash; 4013 else 4014 orig_hash = &ops->func_hash->notrace_hash; 4015 4016 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, 4017 *orig_hash); 4018 if (!new_hash) 4019 goto out; /* warn? */ 4020 4021 mutex_lock(&ftrace_lock); 4022 4023 list_for_each_entry_safe(ftrace_mod, n, head, list) { 4024 4025 if (strcmp(ftrace_mod->module, mod) != 0) 4026 continue; 4027 4028 if (ftrace_mod->func) 4029 func = kstrdup(ftrace_mod->func, GFP_KERNEL); 4030 else 4031 func = kstrdup("*", GFP_KERNEL); 4032 4033 if (!func) /* warn? */ 4034 continue; 4035 4036 list_del(&ftrace_mod->list); 4037 list_add(&ftrace_mod->list, &process_mods); 4038 4039 /* Use the newly allocated func, as it may be "*" */ 4040 kfree(ftrace_mod->func); 4041 ftrace_mod->func = func; 4042 } 4043 4044 mutex_unlock(&ftrace_lock); 4045 4046 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) { 4047 4048 func = ftrace_mod->func; 4049 4050 /* Grabs ftrace_lock, which is why we have this extra step */ 4051 match_records(new_hash, func, strlen(func), mod); 4052 free_ftrace_mod(ftrace_mod); 4053 } 4054 4055 if (enable && list_empty(head)) 4056 new_hash->flags &= ~FTRACE_HASH_FL_MOD; 4057 4058 mutex_lock(&ftrace_lock); 4059 4060 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, 4061 new_hash, enable); 4062 mutex_unlock(&ftrace_lock); 4063 4064 out: 4065 mutex_unlock(&ops->func_hash->regex_lock); 4066 4067 free_ftrace_hash(new_hash); 4068 } 4069 4070 static void process_cached_mods(const char *mod_name) 4071 { 4072 struct trace_array *tr; 4073 char *mod; 4074 4075 mod = kstrdup(mod_name, GFP_KERNEL); 4076 if (!mod) 4077 return; 4078 4079 mutex_lock(&trace_types_lock); 4080 list_for_each_entry(tr, &ftrace_trace_arrays, list) { 4081 if (!list_empty(&tr->mod_trace)) 4082 process_mod_list(&tr->mod_trace, tr->ops, mod, true); 4083 if (!list_empty(&tr->mod_notrace)) 4084 process_mod_list(&tr->mod_notrace, tr->ops, mod, false); 4085 } 4086 mutex_unlock(&trace_types_lock); 4087 4088 kfree(mod); 4089 } 4090 #endif 4091 4092 /* 4093 * We register the module command as a template to show others how 4094 * to register the a command as well. 4095 */ 4096 4097 static int 4098 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash, 4099 char *func_orig, char *cmd, char *module, int enable) 4100 { 4101 char *func; 4102 int ret; 4103 4104 /* match_records() modifies func, and we need the original */ 4105 func = kstrdup(func_orig, GFP_KERNEL); 4106 if (!func) 4107 return -ENOMEM; 4108 4109 /* 4110 * cmd == 'mod' because we only registered this func 4111 * for the 'mod' ftrace_func_command. 4112 * But if you register one func with multiple commands, 4113 * you can tell which command was used by the cmd 4114 * parameter. 4115 */ 4116 ret = match_records(hash, func, strlen(func), module); 4117 kfree(func); 4118 4119 if (!ret) 4120 return cache_mod(tr, func_orig, module, enable); 4121 if (ret < 0) 4122 return ret; 4123 return 0; 4124 } 4125 4126 static struct ftrace_func_command ftrace_mod_cmd = { 4127 .name = "mod", 4128 .func = ftrace_mod_callback, 4129 }; 4130 4131 static int __init ftrace_mod_cmd_init(void) 4132 { 4133 return register_ftrace_command(&ftrace_mod_cmd); 4134 } 4135 core_initcall(ftrace_mod_cmd_init); 4136 4137 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip, 4138 struct ftrace_ops *op, struct pt_regs *pt_regs) 4139 { 4140 struct ftrace_probe_ops *probe_ops; 4141 struct ftrace_func_probe *probe; 4142 4143 probe = container_of(op, struct ftrace_func_probe, ops); 4144 probe_ops = probe->probe_ops; 4145 4146 /* 4147 * Disable preemption for these calls to prevent a RCU grace 4148 * period. This syncs the hash iteration and freeing of items 4149 * on the hash. rcu_read_lock is too dangerous here. 4150 */ 4151 preempt_disable_notrace(); 4152 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data); 4153 preempt_enable_notrace(); 4154 } 4155 4156 struct ftrace_func_map { 4157 struct ftrace_func_entry entry; 4158 void *data; 4159 }; 4160 4161 struct ftrace_func_mapper { 4162 struct ftrace_hash hash; 4163 }; 4164 4165 /** 4166 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper 4167 * 4168 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data. 4169 */ 4170 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void) 4171 { 4172 struct ftrace_hash *hash; 4173 4174 /* 4175 * The mapper is simply a ftrace_hash, but since the entries 4176 * in the hash are not ftrace_func_entry type, we define it 4177 * as a separate structure. 4178 */ 4179 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); 4180 return (struct ftrace_func_mapper *)hash; 4181 } 4182 4183 /** 4184 * ftrace_func_mapper_find_ip - Find some data mapped to an ip 4185 * @mapper: The mapper that has the ip maps 4186 * @ip: the instruction pointer to find the data for 4187 * 4188 * Returns the data mapped to @ip if found otherwise NULL. The return 4189 * is actually the address of the mapper data pointer. The address is 4190 * returned for use cases where the data is no bigger than a long, and 4191 * the user can use the data pointer as its data instead of having to 4192 * allocate more memory for the reference. 4193 */ 4194 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper, 4195 unsigned long ip) 4196 { 4197 struct ftrace_func_entry *entry; 4198 struct ftrace_func_map *map; 4199 4200 entry = ftrace_lookup_ip(&mapper->hash, ip); 4201 if (!entry) 4202 return NULL; 4203 4204 map = (struct ftrace_func_map *)entry; 4205 return &map->data; 4206 } 4207 4208 /** 4209 * ftrace_func_mapper_add_ip - Map some data to an ip 4210 * @mapper: The mapper that has the ip maps 4211 * @ip: The instruction pointer address to map @data to 4212 * @data: The data to map to @ip 4213 * 4214 * Returns 0 on succes otherwise an error. 4215 */ 4216 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper, 4217 unsigned long ip, void *data) 4218 { 4219 struct ftrace_func_entry *entry; 4220 struct ftrace_func_map *map; 4221 4222 entry = ftrace_lookup_ip(&mapper->hash, ip); 4223 if (entry) 4224 return -EBUSY; 4225 4226 map = kmalloc(sizeof(*map), GFP_KERNEL); 4227 if (!map) 4228 return -ENOMEM; 4229 4230 map->entry.ip = ip; 4231 map->data = data; 4232 4233 __add_hash_entry(&mapper->hash, &map->entry); 4234 4235 return 0; 4236 } 4237 4238 /** 4239 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping 4240 * @mapper: The mapper that has the ip maps 4241 * @ip: The instruction pointer address to remove the data from 4242 * 4243 * Returns the data if it is found, otherwise NULL. 4244 * Note, if the data pointer is used as the data itself, (see 4245 * ftrace_func_mapper_find_ip(), then the return value may be meaningless, 4246 * if the data pointer was set to zero. 4247 */ 4248 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper, 4249 unsigned long ip) 4250 { 4251 struct ftrace_func_entry *entry; 4252 struct ftrace_func_map *map; 4253 void *data; 4254 4255 entry = ftrace_lookup_ip(&mapper->hash, ip); 4256 if (!entry) 4257 return NULL; 4258 4259 map = (struct ftrace_func_map *)entry; 4260 data = map->data; 4261 4262 remove_hash_entry(&mapper->hash, entry); 4263 kfree(entry); 4264 4265 return data; 4266 } 4267 4268 /** 4269 * free_ftrace_func_mapper - free a mapping of ips and data 4270 * @mapper: The mapper that has the ip maps 4271 * @free_func: A function to be called on each data item. 4272 * 4273 * This is used to free the function mapper. The @free_func is optional 4274 * and can be used if the data needs to be freed as well. 4275 */ 4276 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper, 4277 ftrace_mapper_func free_func) 4278 { 4279 struct ftrace_func_entry *entry; 4280 struct ftrace_func_map *map; 4281 struct hlist_head *hhd; 4282 int size = 1 << mapper->hash.size_bits; 4283 int i; 4284 4285 if (free_func && mapper->hash.count) { 4286 for (i = 0; i < size; i++) { 4287 hhd = &mapper->hash.buckets[i]; 4288 hlist_for_each_entry(entry, hhd, hlist) { 4289 map = (struct ftrace_func_map *)entry; 4290 free_func(map); 4291 } 4292 } 4293 } 4294 free_ftrace_hash(&mapper->hash); 4295 } 4296 4297 static void release_probe(struct ftrace_func_probe *probe) 4298 { 4299 struct ftrace_probe_ops *probe_ops; 4300 4301 mutex_lock(&ftrace_lock); 4302 4303 WARN_ON(probe->ref <= 0); 4304 4305 /* Subtract the ref that was used to protect this instance */ 4306 probe->ref--; 4307 4308 if (!probe->ref) { 4309 probe_ops = probe->probe_ops; 4310 /* 4311 * Sending zero as ip tells probe_ops to free 4312 * the probe->data itself 4313 */ 4314 if (probe_ops->free) 4315 probe_ops->free(probe_ops, probe->tr, 0, probe->data); 4316 list_del(&probe->list); 4317 kfree(probe); 4318 } 4319 mutex_unlock(&ftrace_lock); 4320 } 4321 4322 static void acquire_probe_locked(struct ftrace_func_probe *probe) 4323 { 4324 /* 4325 * Add one ref to keep it from being freed when releasing the 4326 * ftrace_lock mutex. 4327 */ 4328 probe->ref++; 4329 } 4330 4331 int 4332 register_ftrace_function_probe(char *glob, struct trace_array *tr, 4333 struct ftrace_probe_ops *probe_ops, 4334 void *data) 4335 { 4336 struct ftrace_func_entry *entry; 4337 struct ftrace_func_probe *probe; 4338 struct ftrace_hash **orig_hash; 4339 struct ftrace_hash *old_hash; 4340 struct ftrace_hash *hash; 4341 int count = 0; 4342 int size; 4343 int ret; 4344 int i; 4345 4346 if (WARN_ON(!tr)) 4347 return -EINVAL; 4348 4349 /* We do not support '!' for function probes */ 4350 if (WARN_ON(glob[0] == '!')) 4351 return -EINVAL; 4352 4353 4354 mutex_lock(&ftrace_lock); 4355 /* Check if the probe_ops is already registered */ 4356 list_for_each_entry(probe, &tr->func_probes, list) { 4357 if (probe->probe_ops == probe_ops) 4358 break; 4359 } 4360 if (&probe->list == &tr->func_probes) { 4361 probe = kzalloc(sizeof(*probe), GFP_KERNEL); 4362 if (!probe) { 4363 mutex_unlock(&ftrace_lock); 4364 return -ENOMEM; 4365 } 4366 probe->probe_ops = probe_ops; 4367 probe->ops.func = function_trace_probe_call; 4368 probe->tr = tr; 4369 ftrace_ops_init(&probe->ops); 4370 list_add(&probe->list, &tr->func_probes); 4371 } 4372 4373 acquire_probe_locked(probe); 4374 4375 mutex_unlock(&ftrace_lock); 4376 4377 mutex_lock(&probe->ops.func_hash->regex_lock); 4378 4379 orig_hash = &probe->ops.func_hash->filter_hash; 4380 old_hash = *orig_hash; 4381 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash); 4382 4383 ret = ftrace_match_records(hash, glob, strlen(glob)); 4384 4385 /* Nothing found? */ 4386 if (!ret) 4387 ret = -EINVAL; 4388 4389 if (ret < 0) 4390 goto out; 4391 4392 size = 1 << hash->size_bits; 4393 for (i = 0; i < size; i++) { 4394 hlist_for_each_entry(entry, &hash->buckets[i], hlist) { 4395 if (ftrace_lookup_ip(old_hash, entry->ip)) 4396 continue; 4397 /* 4398 * The caller might want to do something special 4399 * for each function we find. We call the callback 4400 * to give the caller an opportunity to do so. 4401 */ 4402 if (probe_ops->init) { 4403 ret = probe_ops->init(probe_ops, tr, 4404 entry->ip, data, 4405 &probe->data); 4406 if (ret < 0) { 4407 if (probe_ops->free && count) 4408 probe_ops->free(probe_ops, tr, 4409 0, probe->data); 4410 probe->data = NULL; 4411 goto out; 4412 } 4413 } 4414 count++; 4415 } 4416 } 4417 4418 mutex_lock(&ftrace_lock); 4419 4420 if (!count) { 4421 /* Nothing was added? */ 4422 ret = -EINVAL; 4423 goto out_unlock; 4424 } 4425 4426 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash, 4427 hash, 1); 4428 if (ret < 0) 4429 goto err_unlock; 4430 4431 /* One ref for each new function traced */ 4432 probe->ref += count; 4433 4434 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED)) 4435 ret = ftrace_startup(&probe->ops, 0); 4436 4437 out_unlock: 4438 mutex_unlock(&ftrace_lock); 4439 4440 if (!ret) 4441 ret = count; 4442 out: 4443 mutex_unlock(&probe->ops.func_hash->regex_lock); 4444 free_ftrace_hash(hash); 4445 4446 release_probe(probe); 4447 4448 return ret; 4449 4450 err_unlock: 4451 if (!probe_ops->free || !count) 4452 goto out_unlock; 4453 4454 /* Failed to do the move, need to call the free functions */ 4455 for (i = 0; i < size; i++) { 4456 hlist_for_each_entry(entry, &hash->buckets[i], hlist) { 4457 if (ftrace_lookup_ip(old_hash, entry->ip)) 4458 continue; 4459 probe_ops->free(probe_ops, tr, entry->ip, probe->data); 4460 } 4461 } 4462 goto out_unlock; 4463 } 4464 4465 int 4466 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr, 4467 struct ftrace_probe_ops *probe_ops) 4468 { 4469 struct ftrace_ops_hash old_hash_ops; 4470 struct ftrace_func_entry *entry; 4471 struct ftrace_func_probe *probe; 4472 struct ftrace_glob func_g; 4473 struct ftrace_hash **orig_hash; 4474 struct ftrace_hash *old_hash; 4475 struct ftrace_hash *hash = NULL; 4476 struct hlist_node *tmp; 4477 struct hlist_head hhd; 4478 char str[KSYM_SYMBOL_LEN]; 4479 int count = 0; 4480 int i, ret = -ENODEV; 4481 int size; 4482 4483 if (!glob || !strlen(glob) || !strcmp(glob, "*")) 4484 func_g.search = NULL; 4485 else { 4486 int not; 4487 4488 func_g.type = filter_parse_regex(glob, strlen(glob), 4489 &func_g.search, ¬); 4490 func_g.len = strlen(func_g.search); 4491 func_g.search = glob; 4492 4493 /* we do not support '!' for function probes */ 4494 if (WARN_ON(not)) 4495 return -EINVAL; 4496 } 4497 4498 mutex_lock(&ftrace_lock); 4499 /* Check if the probe_ops is already registered */ 4500 list_for_each_entry(probe, &tr->func_probes, list) { 4501 if (probe->probe_ops == probe_ops) 4502 break; 4503 } 4504 if (&probe->list == &tr->func_probes) 4505 goto err_unlock_ftrace; 4506 4507 ret = -EINVAL; 4508 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED)) 4509 goto err_unlock_ftrace; 4510 4511 acquire_probe_locked(probe); 4512 4513 mutex_unlock(&ftrace_lock); 4514 4515 mutex_lock(&probe->ops.func_hash->regex_lock); 4516 4517 orig_hash = &probe->ops.func_hash->filter_hash; 4518 old_hash = *orig_hash; 4519 4520 if (ftrace_hash_empty(old_hash)) 4521 goto out_unlock; 4522 4523 old_hash_ops.filter_hash = old_hash; 4524 /* Probes only have filters */ 4525 old_hash_ops.notrace_hash = NULL; 4526 4527 ret = -ENOMEM; 4528 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash); 4529 if (!hash) 4530 goto out_unlock; 4531 4532 INIT_HLIST_HEAD(&hhd); 4533 4534 size = 1 << hash->size_bits; 4535 for (i = 0; i < size; i++) { 4536 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) { 4537 4538 if (func_g.search) { 4539 kallsyms_lookup(entry->ip, NULL, NULL, 4540 NULL, str); 4541 if (!ftrace_match(str, &func_g)) 4542 continue; 4543 } 4544 count++; 4545 remove_hash_entry(hash, entry); 4546 hlist_add_head(&entry->hlist, &hhd); 4547 } 4548 } 4549 4550 /* Nothing found? */ 4551 if (!count) { 4552 ret = -EINVAL; 4553 goto out_unlock; 4554 } 4555 4556 mutex_lock(&ftrace_lock); 4557 4558 WARN_ON(probe->ref < count); 4559 4560 probe->ref -= count; 4561 4562 if (ftrace_hash_empty(hash)) 4563 ftrace_shutdown(&probe->ops, 0); 4564 4565 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash, 4566 hash, 1); 4567 4568 /* still need to update the function call sites */ 4569 if (ftrace_enabled && !ftrace_hash_empty(hash)) 4570 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS, 4571 &old_hash_ops); 4572 synchronize_sched(); 4573 4574 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) { 4575 hlist_del(&entry->hlist); 4576 if (probe_ops->free) 4577 probe_ops->free(probe_ops, tr, entry->ip, probe->data); 4578 kfree(entry); 4579 } 4580 mutex_unlock(&ftrace_lock); 4581 4582 out_unlock: 4583 mutex_unlock(&probe->ops.func_hash->regex_lock); 4584 free_ftrace_hash(hash); 4585 4586 release_probe(probe); 4587 4588 return ret; 4589 4590 err_unlock_ftrace: 4591 mutex_unlock(&ftrace_lock); 4592 return ret; 4593 } 4594 4595 void clear_ftrace_function_probes(struct trace_array *tr) 4596 { 4597 struct ftrace_func_probe *probe, *n; 4598 4599 list_for_each_entry_safe(probe, n, &tr->func_probes, list) 4600 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops); 4601 } 4602 4603 static LIST_HEAD(ftrace_commands); 4604 static DEFINE_MUTEX(ftrace_cmd_mutex); 4605 4606 /* 4607 * Currently we only register ftrace commands from __init, so mark this 4608 * __init too. 4609 */ 4610 __init int register_ftrace_command(struct ftrace_func_command *cmd) 4611 { 4612 struct ftrace_func_command *p; 4613 int ret = 0; 4614 4615 mutex_lock(&ftrace_cmd_mutex); 4616 list_for_each_entry(p, &ftrace_commands, list) { 4617 if (strcmp(cmd->name, p->name) == 0) { 4618 ret = -EBUSY; 4619 goto out_unlock; 4620 } 4621 } 4622 list_add(&cmd->list, &ftrace_commands); 4623 out_unlock: 4624 mutex_unlock(&ftrace_cmd_mutex); 4625 4626 return ret; 4627 } 4628 4629 /* 4630 * Currently we only unregister ftrace commands from __init, so mark 4631 * this __init too. 4632 */ 4633 __init int unregister_ftrace_command(struct ftrace_func_command *cmd) 4634 { 4635 struct ftrace_func_command *p, *n; 4636 int ret = -ENODEV; 4637 4638 mutex_lock(&ftrace_cmd_mutex); 4639 list_for_each_entry_safe(p, n, &ftrace_commands, list) { 4640 if (strcmp(cmd->name, p->name) == 0) { 4641 ret = 0; 4642 list_del_init(&p->list); 4643 goto out_unlock; 4644 } 4645 } 4646 out_unlock: 4647 mutex_unlock(&ftrace_cmd_mutex); 4648 4649 return ret; 4650 } 4651 4652 static int ftrace_process_regex(struct ftrace_iterator *iter, 4653 char *buff, int len, int enable) 4654 { 4655 struct ftrace_hash *hash = iter->hash; 4656 struct trace_array *tr = iter->ops->private; 4657 char *func, *command, *next = buff; 4658 struct ftrace_func_command *p; 4659 int ret = -EINVAL; 4660 4661 func = strsep(&next, ":"); 4662 4663 if (!next) { 4664 ret = ftrace_match_records(hash, func, len); 4665 if (!ret) 4666 ret = -EINVAL; 4667 if (ret < 0) 4668 return ret; 4669 return 0; 4670 } 4671 4672 /* command found */ 4673 4674 command = strsep(&next, ":"); 4675 4676 mutex_lock(&ftrace_cmd_mutex); 4677 list_for_each_entry(p, &ftrace_commands, list) { 4678 if (strcmp(p->name, command) == 0) { 4679 ret = p->func(tr, hash, func, command, next, enable); 4680 goto out_unlock; 4681 } 4682 } 4683 out_unlock: 4684 mutex_unlock(&ftrace_cmd_mutex); 4685 4686 return ret; 4687 } 4688 4689 static ssize_t 4690 ftrace_regex_write(struct file *file, const char __user *ubuf, 4691 size_t cnt, loff_t *ppos, int enable) 4692 { 4693 struct ftrace_iterator *iter; 4694 struct trace_parser *parser; 4695 ssize_t ret, read; 4696 4697 if (!cnt) 4698 return 0; 4699 4700 if (file->f_mode & FMODE_READ) { 4701 struct seq_file *m = file->private_data; 4702 iter = m->private; 4703 } else 4704 iter = file->private_data; 4705 4706 if (unlikely(ftrace_disabled)) 4707 return -ENODEV; 4708 4709 /* iter->hash is a local copy, so we don't need regex_lock */ 4710 4711 parser = &iter->parser; 4712 read = trace_get_user(parser, ubuf, cnt, ppos); 4713 4714 if (read >= 0 && trace_parser_loaded(parser) && 4715 !trace_parser_cont(parser)) { 4716 ret = ftrace_process_regex(iter, parser->buffer, 4717 parser->idx, enable); 4718 trace_parser_clear(parser); 4719 if (ret < 0) 4720 goto out; 4721 } 4722 4723 ret = read; 4724 out: 4725 return ret; 4726 } 4727 4728 ssize_t 4729 ftrace_filter_write(struct file *file, const char __user *ubuf, 4730 size_t cnt, loff_t *ppos) 4731 { 4732 return ftrace_regex_write(file, ubuf, cnt, ppos, 1); 4733 } 4734 4735 ssize_t 4736 ftrace_notrace_write(struct file *file, const char __user *ubuf, 4737 size_t cnt, loff_t *ppos) 4738 { 4739 return ftrace_regex_write(file, ubuf, cnt, ppos, 0); 4740 } 4741 4742 static int 4743 ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove) 4744 { 4745 struct ftrace_func_entry *entry; 4746 4747 if (!ftrace_location(ip)) 4748 return -EINVAL; 4749 4750 if (remove) { 4751 entry = ftrace_lookup_ip(hash, ip); 4752 if (!entry) 4753 return -ENOENT; 4754 free_hash_entry(hash, entry); 4755 return 0; 4756 } 4757 4758 return add_hash_entry(hash, ip); 4759 } 4760 4761 static int 4762 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len, 4763 unsigned long ip, int remove, int reset, int enable) 4764 { 4765 struct ftrace_hash **orig_hash; 4766 struct ftrace_hash *hash; 4767 int ret; 4768 4769 if (unlikely(ftrace_disabled)) 4770 return -ENODEV; 4771 4772 mutex_lock(&ops->func_hash->regex_lock); 4773 4774 if (enable) 4775 orig_hash = &ops->func_hash->filter_hash; 4776 else 4777 orig_hash = &ops->func_hash->notrace_hash; 4778 4779 if (reset) 4780 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); 4781 else 4782 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); 4783 4784 if (!hash) { 4785 ret = -ENOMEM; 4786 goto out_regex_unlock; 4787 } 4788 4789 if (buf && !ftrace_match_records(hash, buf, len)) { 4790 ret = -EINVAL; 4791 goto out_regex_unlock; 4792 } 4793 if (ip) { 4794 ret = ftrace_match_addr(hash, ip, remove); 4795 if (ret < 0) 4796 goto out_regex_unlock; 4797 } 4798 4799 mutex_lock(&ftrace_lock); 4800 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable); 4801 mutex_unlock(&ftrace_lock); 4802 4803 out_regex_unlock: 4804 mutex_unlock(&ops->func_hash->regex_lock); 4805 4806 free_ftrace_hash(hash); 4807 return ret; 4808 } 4809 4810 static int 4811 ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove, 4812 int reset, int enable) 4813 { 4814 return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable); 4815 } 4816 4817 /** 4818 * ftrace_set_filter_ip - set a function to filter on in ftrace by address 4819 * @ops - the ops to set the filter with 4820 * @ip - the address to add to or remove from the filter. 4821 * @remove - non zero to remove the ip from the filter 4822 * @reset - non zero to reset all filters before applying this filter. 4823 * 4824 * Filters denote which functions should be enabled when tracing is enabled 4825 * If @ip is NULL, it failes to update filter. 4826 */ 4827 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, 4828 int remove, int reset) 4829 { 4830 ftrace_ops_init(ops); 4831 return ftrace_set_addr(ops, ip, remove, reset, 1); 4832 } 4833 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip); 4834 4835 /** 4836 * ftrace_ops_set_global_filter - setup ops to use global filters 4837 * @ops - the ops which will use the global filters 4838 * 4839 * ftrace users who need global function trace filtering should call this. 4840 * It can set the global filter only if ops were not initialized before. 4841 */ 4842 void ftrace_ops_set_global_filter(struct ftrace_ops *ops) 4843 { 4844 if (ops->flags & FTRACE_OPS_FL_INITIALIZED) 4845 return; 4846 4847 ftrace_ops_init(ops); 4848 ops->func_hash = &global_ops.local_hash; 4849 } 4850 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter); 4851 4852 static int 4853 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, 4854 int reset, int enable) 4855 { 4856 return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable); 4857 } 4858 4859 /** 4860 * ftrace_set_filter - set a function to filter on in ftrace 4861 * @ops - the ops to set the filter with 4862 * @buf - the string that holds the function filter text. 4863 * @len - the length of the string. 4864 * @reset - non zero to reset all filters before applying this filter. 4865 * 4866 * Filters denote which functions should be enabled when tracing is enabled. 4867 * If @buf is NULL and reset is set, all functions will be enabled for tracing. 4868 */ 4869 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, 4870 int len, int reset) 4871 { 4872 ftrace_ops_init(ops); 4873 return ftrace_set_regex(ops, buf, len, reset, 1); 4874 } 4875 EXPORT_SYMBOL_GPL(ftrace_set_filter); 4876 4877 /** 4878 * ftrace_set_notrace - set a function to not trace in ftrace 4879 * @ops - the ops to set the notrace filter with 4880 * @buf - the string that holds the function notrace text. 4881 * @len - the length of the string. 4882 * @reset - non zero to reset all filters before applying this filter. 4883 * 4884 * Notrace Filters denote which functions should not be enabled when tracing 4885 * is enabled. If @buf is NULL and reset is set, all functions will be enabled 4886 * for tracing. 4887 */ 4888 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, 4889 int len, int reset) 4890 { 4891 ftrace_ops_init(ops); 4892 return ftrace_set_regex(ops, buf, len, reset, 0); 4893 } 4894 EXPORT_SYMBOL_GPL(ftrace_set_notrace); 4895 /** 4896 * ftrace_set_global_filter - set a function to filter on with global tracers 4897 * @buf - the string that holds the function filter text. 4898 * @len - the length of the string. 4899 * @reset - non zero to reset all filters before applying this filter. 4900 * 4901 * Filters denote which functions should be enabled when tracing is enabled. 4902 * If @buf is NULL and reset is set, all functions will be enabled for tracing. 4903 */ 4904 void ftrace_set_global_filter(unsigned char *buf, int len, int reset) 4905 { 4906 ftrace_set_regex(&global_ops, buf, len, reset, 1); 4907 } 4908 EXPORT_SYMBOL_GPL(ftrace_set_global_filter); 4909 4910 /** 4911 * ftrace_set_global_notrace - set a function to not trace with global tracers 4912 * @buf - the string that holds the function notrace text. 4913 * @len - the length of the string. 4914 * @reset - non zero to reset all filters before applying this filter. 4915 * 4916 * Notrace Filters denote which functions should not be enabled when tracing 4917 * is enabled. If @buf is NULL and reset is set, all functions will be enabled 4918 * for tracing. 4919 */ 4920 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset) 4921 { 4922 ftrace_set_regex(&global_ops, buf, len, reset, 0); 4923 } 4924 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace); 4925 4926 /* 4927 * command line interface to allow users to set filters on boot up. 4928 */ 4929 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE 4930 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata; 4931 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata; 4932 4933 /* Used by function selftest to not test if filter is set */ 4934 bool ftrace_filter_param __initdata; 4935 4936 static int __init set_ftrace_notrace(char *str) 4937 { 4938 ftrace_filter_param = true; 4939 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE); 4940 return 1; 4941 } 4942 __setup("ftrace_notrace=", set_ftrace_notrace); 4943 4944 static int __init set_ftrace_filter(char *str) 4945 { 4946 ftrace_filter_param = true; 4947 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE); 4948 return 1; 4949 } 4950 __setup("ftrace_filter=", set_ftrace_filter); 4951 4952 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 4953 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; 4954 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata; 4955 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer); 4956 4957 static int __init set_graph_function(char *str) 4958 { 4959 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); 4960 return 1; 4961 } 4962 __setup("ftrace_graph_filter=", set_graph_function); 4963 4964 static int __init set_graph_notrace_function(char *str) 4965 { 4966 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE); 4967 return 1; 4968 } 4969 __setup("ftrace_graph_notrace=", set_graph_notrace_function); 4970 4971 static int __init set_graph_max_depth_function(char *str) 4972 { 4973 if (!str) 4974 return 0; 4975 fgraph_max_depth = simple_strtoul(str, NULL, 0); 4976 return 1; 4977 } 4978 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function); 4979 4980 static void __init set_ftrace_early_graph(char *buf, int enable) 4981 { 4982 int ret; 4983 char *func; 4984 struct ftrace_hash *hash; 4985 4986 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); 4987 if (WARN_ON(!hash)) 4988 return; 4989 4990 while (buf) { 4991 func = strsep(&buf, ","); 4992 /* we allow only one expression at a time */ 4993 ret = ftrace_graph_set_hash(hash, func); 4994 if (ret) 4995 printk(KERN_DEBUG "ftrace: function %s not " 4996 "traceable\n", func); 4997 } 4998 4999 if (enable) 5000 ftrace_graph_hash = hash; 5001 else 5002 ftrace_graph_notrace_hash = hash; 5003 } 5004 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 5005 5006 void __init 5007 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable) 5008 { 5009 char *func; 5010 5011 ftrace_ops_init(ops); 5012 5013 while (buf) { 5014 func = strsep(&buf, ","); 5015 ftrace_set_regex(ops, func, strlen(func), 0, enable); 5016 } 5017 } 5018 5019 static void __init set_ftrace_early_filters(void) 5020 { 5021 if (ftrace_filter_buf[0]) 5022 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1); 5023 if (ftrace_notrace_buf[0]) 5024 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0); 5025 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 5026 if (ftrace_graph_buf[0]) 5027 set_ftrace_early_graph(ftrace_graph_buf, 1); 5028 if (ftrace_graph_notrace_buf[0]) 5029 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0); 5030 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 5031 } 5032 5033 int ftrace_regex_release(struct inode *inode, struct file *file) 5034 { 5035 struct seq_file *m = (struct seq_file *)file->private_data; 5036 struct ftrace_iterator *iter; 5037 struct ftrace_hash **orig_hash; 5038 struct trace_parser *parser; 5039 int filter_hash; 5040 int ret; 5041 5042 if (file->f_mode & FMODE_READ) { 5043 iter = m->private; 5044 seq_release(inode, file); 5045 } else 5046 iter = file->private_data; 5047 5048 parser = &iter->parser; 5049 if (trace_parser_loaded(parser)) { 5050 parser->buffer[parser->idx] = 0; 5051 ftrace_match_records(iter->hash, parser->buffer, parser->idx); 5052 } 5053 5054 trace_parser_put(parser); 5055 5056 mutex_lock(&iter->ops->func_hash->regex_lock); 5057 5058 if (file->f_mode & FMODE_WRITE) { 5059 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER); 5060 5061 if (filter_hash) { 5062 orig_hash = &iter->ops->func_hash->filter_hash; 5063 if (iter->tr && !list_empty(&iter->tr->mod_trace)) 5064 iter->hash->flags |= FTRACE_HASH_FL_MOD; 5065 } else 5066 orig_hash = &iter->ops->func_hash->notrace_hash; 5067 5068 mutex_lock(&ftrace_lock); 5069 ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash, 5070 iter->hash, filter_hash); 5071 mutex_unlock(&ftrace_lock); 5072 } else { 5073 /* For read only, the hash is the ops hash */ 5074 iter->hash = NULL; 5075 } 5076 5077 mutex_unlock(&iter->ops->func_hash->regex_lock); 5078 free_ftrace_hash(iter->hash); 5079 kfree(iter); 5080 5081 return 0; 5082 } 5083 5084 static const struct file_operations ftrace_avail_fops = { 5085 .open = ftrace_avail_open, 5086 .read = seq_read, 5087 .llseek = seq_lseek, 5088 .release = seq_release_private, 5089 }; 5090 5091 static const struct file_operations ftrace_enabled_fops = { 5092 .open = ftrace_enabled_open, 5093 .read = seq_read, 5094 .llseek = seq_lseek, 5095 .release = seq_release_private, 5096 }; 5097 5098 static const struct file_operations ftrace_filter_fops = { 5099 .open = ftrace_filter_open, 5100 .read = seq_read, 5101 .write = ftrace_filter_write, 5102 .llseek = tracing_lseek, 5103 .release = ftrace_regex_release, 5104 }; 5105 5106 static const struct file_operations ftrace_notrace_fops = { 5107 .open = ftrace_notrace_open, 5108 .read = seq_read, 5109 .write = ftrace_notrace_write, 5110 .llseek = tracing_lseek, 5111 .release = ftrace_regex_release, 5112 }; 5113 5114 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 5115 5116 static DEFINE_MUTEX(graph_lock); 5117 5118 struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH; 5119 struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH; 5120 5121 enum graph_filter_type { 5122 GRAPH_FILTER_NOTRACE = 0, 5123 GRAPH_FILTER_FUNCTION, 5124 }; 5125 5126 #define FTRACE_GRAPH_EMPTY ((void *)1) 5127 5128 struct ftrace_graph_data { 5129 struct ftrace_hash *hash; 5130 struct ftrace_func_entry *entry; 5131 int idx; /* for hash table iteration */ 5132 enum graph_filter_type type; 5133 struct ftrace_hash *new_hash; 5134 const struct seq_operations *seq_ops; 5135 struct trace_parser parser; 5136 }; 5137 5138 static void * 5139 __g_next(struct seq_file *m, loff_t *pos) 5140 { 5141 struct ftrace_graph_data *fgd = m->private; 5142 struct ftrace_func_entry *entry = fgd->entry; 5143 struct hlist_head *head; 5144 int i, idx = fgd->idx; 5145 5146 if (*pos >= fgd->hash->count) 5147 return NULL; 5148 5149 if (entry) { 5150 hlist_for_each_entry_continue(entry, hlist) { 5151 fgd->entry = entry; 5152 return entry; 5153 } 5154 5155 idx++; 5156 } 5157 5158 for (i = idx; i < 1 << fgd->hash->size_bits; i++) { 5159 head = &fgd->hash->buckets[i]; 5160 hlist_for_each_entry(entry, head, hlist) { 5161 fgd->entry = entry; 5162 fgd->idx = i; 5163 return entry; 5164 } 5165 } 5166 return NULL; 5167 } 5168 5169 static void * 5170 g_next(struct seq_file *m, void *v, loff_t *pos) 5171 { 5172 (*pos)++; 5173 return __g_next(m, pos); 5174 } 5175 5176 static void *g_start(struct seq_file *m, loff_t *pos) 5177 { 5178 struct ftrace_graph_data *fgd = m->private; 5179 5180 mutex_lock(&graph_lock); 5181 5182 if (fgd->type == GRAPH_FILTER_FUNCTION) 5183 fgd->hash = rcu_dereference_protected(ftrace_graph_hash, 5184 lockdep_is_held(&graph_lock)); 5185 else 5186 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash, 5187 lockdep_is_held(&graph_lock)); 5188 5189 /* Nothing, tell g_show to print all functions are enabled */ 5190 if (ftrace_hash_empty(fgd->hash) && !*pos) 5191 return FTRACE_GRAPH_EMPTY; 5192 5193 fgd->idx = 0; 5194 fgd->entry = NULL; 5195 return __g_next(m, pos); 5196 } 5197 5198 static void g_stop(struct seq_file *m, void *p) 5199 { 5200 mutex_unlock(&graph_lock); 5201 } 5202 5203 static int g_show(struct seq_file *m, void *v) 5204 { 5205 struct ftrace_func_entry *entry = v; 5206 5207 if (!entry) 5208 return 0; 5209 5210 if (entry == FTRACE_GRAPH_EMPTY) { 5211 struct ftrace_graph_data *fgd = m->private; 5212 5213 if (fgd->type == GRAPH_FILTER_FUNCTION) 5214 seq_puts(m, "#### all functions enabled ####\n"); 5215 else 5216 seq_puts(m, "#### no functions disabled ####\n"); 5217 return 0; 5218 } 5219 5220 seq_printf(m, "%ps\n", (void *)entry->ip); 5221 5222 return 0; 5223 } 5224 5225 static const struct seq_operations ftrace_graph_seq_ops = { 5226 .start = g_start, 5227 .next = g_next, 5228 .stop = g_stop, 5229 .show = g_show, 5230 }; 5231 5232 static int 5233 __ftrace_graph_open(struct inode *inode, struct file *file, 5234 struct ftrace_graph_data *fgd) 5235 { 5236 int ret = 0; 5237 struct ftrace_hash *new_hash = NULL; 5238 5239 if (file->f_mode & FMODE_WRITE) { 5240 const int size_bits = FTRACE_HASH_DEFAULT_BITS; 5241 5242 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX)) 5243 return -ENOMEM; 5244 5245 if (file->f_flags & O_TRUNC) 5246 new_hash = alloc_ftrace_hash(size_bits); 5247 else 5248 new_hash = alloc_and_copy_ftrace_hash(size_bits, 5249 fgd->hash); 5250 if (!new_hash) { 5251 ret = -ENOMEM; 5252 goto out; 5253 } 5254 } 5255 5256 if (file->f_mode & FMODE_READ) { 5257 ret = seq_open(file, &ftrace_graph_seq_ops); 5258 if (!ret) { 5259 struct seq_file *m = file->private_data; 5260 m->private = fgd; 5261 } else { 5262 /* Failed */ 5263 free_ftrace_hash(new_hash); 5264 new_hash = NULL; 5265 } 5266 } else 5267 file->private_data = fgd; 5268 5269 out: 5270 if (ret < 0 && file->f_mode & FMODE_WRITE) 5271 trace_parser_put(&fgd->parser); 5272 5273 fgd->new_hash = new_hash; 5274 5275 /* 5276 * All uses of fgd->hash must be taken with the graph_lock 5277 * held. The graph_lock is going to be released, so force 5278 * fgd->hash to be reinitialized when it is taken again. 5279 */ 5280 fgd->hash = NULL; 5281 5282 return ret; 5283 } 5284 5285 static int 5286 ftrace_graph_open(struct inode *inode, struct file *file) 5287 { 5288 struct ftrace_graph_data *fgd; 5289 int ret; 5290 5291 if (unlikely(ftrace_disabled)) 5292 return -ENODEV; 5293 5294 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL); 5295 if (fgd == NULL) 5296 return -ENOMEM; 5297 5298 mutex_lock(&graph_lock); 5299 5300 fgd->hash = rcu_dereference_protected(ftrace_graph_hash, 5301 lockdep_is_held(&graph_lock)); 5302 fgd->type = GRAPH_FILTER_FUNCTION; 5303 fgd->seq_ops = &ftrace_graph_seq_ops; 5304 5305 ret = __ftrace_graph_open(inode, file, fgd); 5306 if (ret < 0) 5307 kfree(fgd); 5308 5309 mutex_unlock(&graph_lock); 5310 return ret; 5311 } 5312 5313 static int 5314 ftrace_graph_notrace_open(struct inode *inode, struct file *file) 5315 { 5316 struct ftrace_graph_data *fgd; 5317 int ret; 5318 5319 if (unlikely(ftrace_disabled)) 5320 return -ENODEV; 5321 5322 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL); 5323 if (fgd == NULL) 5324 return -ENOMEM; 5325 5326 mutex_lock(&graph_lock); 5327 5328 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash, 5329 lockdep_is_held(&graph_lock)); 5330 fgd->type = GRAPH_FILTER_NOTRACE; 5331 fgd->seq_ops = &ftrace_graph_seq_ops; 5332 5333 ret = __ftrace_graph_open(inode, file, fgd); 5334 if (ret < 0) 5335 kfree(fgd); 5336 5337 mutex_unlock(&graph_lock); 5338 return ret; 5339 } 5340 5341 static int 5342 ftrace_graph_release(struct inode *inode, struct file *file) 5343 { 5344 struct ftrace_graph_data *fgd; 5345 struct ftrace_hash *old_hash, *new_hash; 5346 struct trace_parser *parser; 5347 int ret = 0; 5348 5349 if (file->f_mode & FMODE_READ) { 5350 struct seq_file *m = file->private_data; 5351 5352 fgd = m->private; 5353 seq_release(inode, file); 5354 } else { 5355 fgd = file->private_data; 5356 } 5357 5358 5359 if (file->f_mode & FMODE_WRITE) { 5360 5361 parser = &fgd->parser; 5362 5363 if (trace_parser_loaded((parser))) { 5364 parser->buffer[parser->idx] = 0; 5365 ret = ftrace_graph_set_hash(fgd->new_hash, 5366 parser->buffer); 5367 } 5368 5369 trace_parser_put(parser); 5370 5371 new_hash = __ftrace_hash_move(fgd->new_hash); 5372 if (!new_hash) { 5373 ret = -ENOMEM; 5374 goto out; 5375 } 5376 5377 mutex_lock(&graph_lock); 5378 5379 if (fgd->type == GRAPH_FILTER_FUNCTION) { 5380 old_hash = rcu_dereference_protected(ftrace_graph_hash, 5381 lockdep_is_held(&graph_lock)); 5382 rcu_assign_pointer(ftrace_graph_hash, new_hash); 5383 } else { 5384 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash, 5385 lockdep_is_held(&graph_lock)); 5386 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash); 5387 } 5388 5389 mutex_unlock(&graph_lock); 5390 5391 /* Wait till all users are no longer using the old hash */ 5392 synchronize_sched(); 5393 5394 free_ftrace_hash(old_hash); 5395 } 5396 5397 out: 5398 free_ftrace_hash(fgd->new_hash); 5399 kfree(fgd); 5400 5401 return ret; 5402 } 5403 5404 static int 5405 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer) 5406 { 5407 struct ftrace_glob func_g; 5408 struct dyn_ftrace *rec; 5409 struct ftrace_page *pg; 5410 struct ftrace_func_entry *entry; 5411 int fail = 1; 5412 int not; 5413 5414 /* decode regex */ 5415 func_g.type = filter_parse_regex(buffer, strlen(buffer), 5416 &func_g.search, ¬); 5417 5418 func_g.len = strlen(func_g.search); 5419 5420 mutex_lock(&ftrace_lock); 5421 5422 if (unlikely(ftrace_disabled)) { 5423 mutex_unlock(&ftrace_lock); 5424 return -ENODEV; 5425 } 5426 5427 do_for_each_ftrace_rec(pg, rec) { 5428 5429 if (rec->flags & FTRACE_FL_DISABLED) 5430 continue; 5431 5432 if (ftrace_match_record(rec, &func_g, NULL, 0)) { 5433 entry = ftrace_lookup_ip(hash, rec->ip); 5434 5435 if (!not) { 5436 fail = 0; 5437 5438 if (entry) 5439 continue; 5440 if (add_hash_entry(hash, rec->ip) < 0) 5441 goto out; 5442 } else { 5443 if (entry) { 5444 free_hash_entry(hash, entry); 5445 fail = 0; 5446 } 5447 } 5448 } 5449 } while_for_each_ftrace_rec(); 5450 out: 5451 mutex_unlock(&ftrace_lock); 5452 5453 if (fail) 5454 return -EINVAL; 5455 5456 return 0; 5457 } 5458 5459 static ssize_t 5460 ftrace_graph_write(struct file *file, const char __user *ubuf, 5461 size_t cnt, loff_t *ppos) 5462 { 5463 ssize_t read, ret = 0; 5464 struct ftrace_graph_data *fgd = file->private_data; 5465 struct trace_parser *parser; 5466 5467 if (!cnt) 5468 return 0; 5469 5470 /* Read mode uses seq functions */ 5471 if (file->f_mode & FMODE_READ) { 5472 struct seq_file *m = file->private_data; 5473 fgd = m->private; 5474 } 5475 5476 parser = &fgd->parser; 5477 5478 read = trace_get_user(parser, ubuf, cnt, ppos); 5479 5480 if (read >= 0 && trace_parser_loaded(parser) && 5481 !trace_parser_cont(parser)) { 5482 5483 ret = ftrace_graph_set_hash(fgd->new_hash, 5484 parser->buffer); 5485 trace_parser_clear(parser); 5486 } 5487 5488 if (!ret) 5489 ret = read; 5490 5491 return ret; 5492 } 5493 5494 static const struct file_operations ftrace_graph_fops = { 5495 .open = ftrace_graph_open, 5496 .read = seq_read, 5497 .write = ftrace_graph_write, 5498 .llseek = tracing_lseek, 5499 .release = ftrace_graph_release, 5500 }; 5501 5502 static const struct file_operations ftrace_graph_notrace_fops = { 5503 .open = ftrace_graph_notrace_open, 5504 .read = seq_read, 5505 .write = ftrace_graph_write, 5506 .llseek = tracing_lseek, 5507 .release = ftrace_graph_release, 5508 }; 5509 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 5510 5511 void ftrace_create_filter_files(struct ftrace_ops *ops, 5512 struct dentry *parent) 5513 { 5514 5515 trace_create_file("set_ftrace_filter", 0644, parent, 5516 ops, &ftrace_filter_fops); 5517 5518 trace_create_file("set_ftrace_notrace", 0644, parent, 5519 ops, &ftrace_notrace_fops); 5520 } 5521 5522 /* 5523 * The name "destroy_filter_files" is really a misnomer. Although 5524 * in the future, it may actualy delete the files, but this is 5525 * really intended to make sure the ops passed in are disabled 5526 * and that when this function returns, the caller is free to 5527 * free the ops. 5528 * 5529 * The "destroy" name is only to match the "create" name that this 5530 * should be paired with. 5531 */ 5532 void ftrace_destroy_filter_files(struct ftrace_ops *ops) 5533 { 5534 mutex_lock(&ftrace_lock); 5535 if (ops->flags & FTRACE_OPS_FL_ENABLED) 5536 ftrace_shutdown(ops, 0); 5537 ops->flags |= FTRACE_OPS_FL_DELETED; 5538 mutex_unlock(&ftrace_lock); 5539 } 5540 5541 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer) 5542 { 5543 5544 trace_create_file("available_filter_functions", 0444, 5545 d_tracer, NULL, &ftrace_avail_fops); 5546 5547 trace_create_file("enabled_functions", 0444, 5548 d_tracer, NULL, &ftrace_enabled_fops); 5549 5550 ftrace_create_filter_files(&global_ops, d_tracer); 5551 5552 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 5553 trace_create_file("set_graph_function", 0444, d_tracer, 5554 NULL, 5555 &ftrace_graph_fops); 5556 trace_create_file("set_graph_notrace", 0444, d_tracer, 5557 NULL, 5558 &ftrace_graph_notrace_fops); 5559 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 5560 5561 return 0; 5562 } 5563 5564 static int ftrace_cmp_ips(const void *a, const void *b) 5565 { 5566 const unsigned long *ipa = a; 5567 const unsigned long *ipb = b; 5568 5569 if (*ipa > *ipb) 5570 return 1; 5571 if (*ipa < *ipb) 5572 return -1; 5573 return 0; 5574 } 5575 5576 static int ftrace_process_locs(struct module *mod, 5577 unsigned long *start, 5578 unsigned long *end) 5579 { 5580 struct ftrace_page *start_pg; 5581 struct ftrace_page *pg; 5582 struct dyn_ftrace *rec; 5583 unsigned long count; 5584 unsigned long *p; 5585 unsigned long addr; 5586 unsigned long flags = 0; /* Shut up gcc */ 5587 int ret = -ENOMEM; 5588 5589 count = end - start; 5590 5591 if (!count) 5592 return 0; 5593 5594 sort(start, count, sizeof(*start), 5595 ftrace_cmp_ips, NULL); 5596 5597 start_pg = ftrace_allocate_pages(count); 5598 if (!start_pg) 5599 return -ENOMEM; 5600 5601 mutex_lock(&ftrace_lock); 5602 5603 /* 5604 * Core and each module needs their own pages, as 5605 * modules will free them when they are removed. 5606 * Force a new page to be allocated for modules. 5607 */ 5608 if (!mod) { 5609 WARN_ON(ftrace_pages || ftrace_pages_start); 5610 /* First initialization */ 5611 ftrace_pages = ftrace_pages_start = start_pg; 5612 } else { 5613 if (!ftrace_pages) 5614 goto out; 5615 5616 if (WARN_ON(ftrace_pages->next)) { 5617 /* Hmm, we have free pages? */ 5618 while (ftrace_pages->next) 5619 ftrace_pages = ftrace_pages->next; 5620 } 5621 5622 ftrace_pages->next = start_pg; 5623 } 5624 5625 p = start; 5626 pg = start_pg; 5627 while (p < end) { 5628 addr = ftrace_call_adjust(*p++); 5629 /* 5630 * Some architecture linkers will pad between 5631 * the different mcount_loc sections of different 5632 * object files to satisfy alignments. 5633 * Skip any NULL pointers. 5634 */ 5635 if (!addr) 5636 continue; 5637 5638 if (pg->index == pg->size) { 5639 /* We should have allocated enough */ 5640 if (WARN_ON(!pg->next)) 5641 break; 5642 pg = pg->next; 5643 } 5644 5645 rec = &pg->records[pg->index++]; 5646 rec->ip = addr; 5647 } 5648 5649 /* We should have used all pages */ 5650 WARN_ON(pg->next); 5651 5652 /* Assign the last page to ftrace_pages */ 5653 ftrace_pages = pg; 5654 5655 /* 5656 * We only need to disable interrupts on start up 5657 * because we are modifying code that an interrupt 5658 * may execute, and the modification is not atomic. 5659 * But for modules, nothing runs the code we modify 5660 * until we are finished with it, and there's no 5661 * reason to cause large interrupt latencies while we do it. 5662 */ 5663 if (!mod) 5664 local_irq_save(flags); 5665 ftrace_update_code(mod, start_pg); 5666 if (!mod) 5667 local_irq_restore(flags); 5668 ret = 0; 5669 out: 5670 mutex_unlock(&ftrace_lock); 5671 5672 return ret; 5673 } 5674 5675 #ifdef CONFIG_MODULES 5676 5677 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next) 5678 5679 static int referenced_filters(struct dyn_ftrace *rec) 5680 { 5681 struct ftrace_ops *ops; 5682 int cnt = 0; 5683 5684 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) { 5685 if (ops_references_rec(ops, rec)) 5686 cnt++; 5687 } 5688 5689 return cnt; 5690 } 5691 5692 static void 5693 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash) 5694 { 5695 struct ftrace_func_entry *entry; 5696 struct dyn_ftrace *rec; 5697 int i; 5698 5699 if (ftrace_hash_empty(hash)) 5700 return; 5701 5702 for (i = 0; i < pg->index; i++) { 5703 rec = &pg->records[i]; 5704 entry = __ftrace_lookup_ip(hash, rec->ip); 5705 /* 5706 * Do not allow this rec to match again. 5707 * Yeah, it may waste some memory, but will be removed 5708 * if/when the hash is modified again. 5709 */ 5710 if (entry) 5711 entry->ip = 0; 5712 } 5713 } 5714 5715 /* Clear any records from hashs */ 5716 static void clear_mod_from_hashes(struct ftrace_page *pg) 5717 { 5718 struct trace_array *tr; 5719 5720 mutex_lock(&trace_types_lock); 5721 list_for_each_entry(tr, &ftrace_trace_arrays, list) { 5722 if (!tr->ops || !tr->ops->func_hash) 5723 continue; 5724 mutex_lock(&tr->ops->func_hash->regex_lock); 5725 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash); 5726 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash); 5727 mutex_unlock(&tr->ops->func_hash->regex_lock); 5728 } 5729 mutex_unlock(&trace_types_lock); 5730 } 5731 5732 void ftrace_release_mod(struct module *mod) 5733 { 5734 struct dyn_ftrace *rec; 5735 struct ftrace_page **last_pg; 5736 struct ftrace_page *tmp_page = NULL; 5737 struct ftrace_page *pg; 5738 int order; 5739 5740 mutex_lock(&ftrace_lock); 5741 5742 if (ftrace_disabled) 5743 goto out_unlock; 5744 5745 /* 5746 * Each module has its own ftrace_pages, remove 5747 * them from the list. 5748 */ 5749 last_pg = &ftrace_pages_start; 5750 for (pg = ftrace_pages_start; pg; pg = *last_pg) { 5751 rec = &pg->records[0]; 5752 if (within_module_core(rec->ip, mod)) { 5753 /* 5754 * As core pages are first, the first 5755 * page should never be a module page. 5756 */ 5757 if (WARN_ON(pg == ftrace_pages_start)) 5758 goto out_unlock; 5759 5760 /* Check if we are deleting the last page */ 5761 if (pg == ftrace_pages) 5762 ftrace_pages = next_to_ftrace_page(last_pg); 5763 5764 ftrace_update_tot_cnt -= pg->index; 5765 *last_pg = pg->next; 5766 5767 pg->next = tmp_page; 5768 tmp_page = pg; 5769 } else 5770 last_pg = &pg->next; 5771 } 5772 out_unlock: 5773 mutex_unlock(&ftrace_lock); 5774 5775 for (pg = tmp_page; pg; pg = tmp_page) { 5776 5777 /* Needs to be called outside of ftrace_lock */ 5778 clear_mod_from_hashes(pg); 5779 5780 order = get_count_order(pg->size / ENTRIES_PER_PAGE); 5781 free_pages((unsigned long)pg->records, order); 5782 tmp_page = pg->next; 5783 kfree(pg); 5784 } 5785 } 5786 5787 void ftrace_module_enable(struct module *mod) 5788 { 5789 struct dyn_ftrace *rec; 5790 struct ftrace_page *pg; 5791 5792 mutex_lock(&ftrace_lock); 5793 5794 if (ftrace_disabled) 5795 goto out_unlock; 5796 5797 /* 5798 * If the tracing is enabled, go ahead and enable the record. 5799 * 5800 * The reason not to enable the record immediatelly is the 5801 * inherent check of ftrace_make_nop/ftrace_make_call for 5802 * correct previous instructions. Making first the NOP 5803 * conversion puts the module to the correct state, thus 5804 * passing the ftrace_make_call check. 5805 * 5806 * We also delay this to after the module code already set the 5807 * text to read-only, as we now need to set it back to read-write 5808 * so that we can modify the text. 5809 */ 5810 if (ftrace_start_up) 5811 ftrace_arch_code_modify_prepare(); 5812 5813 do_for_each_ftrace_rec(pg, rec) { 5814 int cnt; 5815 /* 5816 * do_for_each_ftrace_rec() is a double loop. 5817 * module text shares the pg. If a record is 5818 * not part of this module, then skip this pg, 5819 * which the "break" will do. 5820 */ 5821 if (!within_module_core(rec->ip, mod)) 5822 break; 5823 5824 cnt = 0; 5825 5826 /* 5827 * When adding a module, we need to check if tracers are 5828 * currently enabled and if they are, and can trace this record, 5829 * we need to enable the module functions as well as update the 5830 * reference counts for those function records. 5831 */ 5832 if (ftrace_start_up) 5833 cnt += referenced_filters(rec); 5834 5835 /* This clears FTRACE_FL_DISABLED */ 5836 rec->flags = cnt; 5837 5838 if (ftrace_start_up && cnt) { 5839 int failed = __ftrace_replace_code(rec, 1); 5840 if (failed) { 5841 ftrace_bug(failed, rec); 5842 goto out_loop; 5843 } 5844 } 5845 5846 } while_for_each_ftrace_rec(); 5847 5848 out_loop: 5849 if (ftrace_start_up) 5850 ftrace_arch_code_modify_post_process(); 5851 5852 out_unlock: 5853 mutex_unlock(&ftrace_lock); 5854 5855 process_cached_mods(mod->name); 5856 } 5857 5858 void ftrace_module_init(struct module *mod) 5859 { 5860 if (ftrace_disabled || !mod->num_ftrace_callsites) 5861 return; 5862 5863 ftrace_process_locs(mod, mod->ftrace_callsites, 5864 mod->ftrace_callsites + mod->num_ftrace_callsites); 5865 } 5866 #endif /* CONFIG_MODULES */ 5867 5868 void __init ftrace_free_init_mem(void) 5869 { 5870 unsigned long start = (unsigned long)(&__init_begin); 5871 unsigned long end = (unsigned long)(&__init_end); 5872 struct ftrace_page **last_pg = &ftrace_pages_start; 5873 struct ftrace_page *pg; 5874 struct dyn_ftrace *rec; 5875 struct dyn_ftrace key; 5876 int order; 5877 5878 key.ip = start; 5879 key.flags = end; /* overload flags, as it is unsigned long */ 5880 5881 mutex_lock(&ftrace_lock); 5882 5883 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) { 5884 if (end < pg->records[0].ip || 5885 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE)) 5886 continue; 5887 again: 5888 rec = bsearch(&key, pg->records, pg->index, 5889 sizeof(struct dyn_ftrace), 5890 ftrace_cmp_recs); 5891 if (!rec) 5892 continue; 5893 pg->index--; 5894 ftrace_update_tot_cnt--; 5895 if (!pg->index) { 5896 *last_pg = pg->next; 5897 order = get_count_order(pg->size / ENTRIES_PER_PAGE); 5898 free_pages((unsigned long)pg->records, order); 5899 kfree(pg); 5900 pg = container_of(last_pg, struct ftrace_page, next); 5901 if (!(*last_pg)) 5902 ftrace_pages = pg; 5903 continue; 5904 } 5905 memmove(rec, rec + 1, 5906 (pg->index - (rec - pg->records)) * sizeof(*rec)); 5907 /* More than one function may be in this block */ 5908 goto again; 5909 } 5910 mutex_unlock(&ftrace_lock); 5911 } 5912 5913 void __init ftrace_init(void) 5914 { 5915 extern unsigned long __start_mcount_loc[]; 5916 extern unsigned long __stop_mcount_loc[]; 5917 unsigned long count, flags; 5918 int ret; 5919 5920 local_irq_save(flags); 5921 ret = ftrace_dyn_arch_init(); 5922 local_irq_restore(flags); 5923 if (ret) 5924 goto failed; 5925 5926 count = __stop_mcount_loc - __start_mcount_loc; 5927 if (!count) { 5928 pr_info("ftrace: No functions to be traced?\n"); 5929 goto failed; 5930 } 5931 5932 pr_info("ftrace: allocating %ld entries in %ld pages\n", 5933 count, count / ENTRIES_PER_PAGE + 1); 5934 5935 last_ftrace_enabled = ftrace_enabled = 1; 5936 5937 ret = ftrace_process_locs(NULL, 5938 __start_mcount_loc, 5939 __stop_mcount_loc); 5940 5941 set_ftrace_early_filters(); 5942 5943 return; 5944 failed: 5945 ftrace_disabled = 1; 5946 } 5947 5948 /* Do nothing if arch does not support this */ 5949 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops) 5950 { 5951 } 5952 5953 static void ftrace_update_trampoline(struct ftrace_ops *ops) 5954 { 5955 arch_ftrace_update_trampoline(ops); 5956 } 5957 5958 void ftrace_init_trace_array(struct trace_array *tr) 5959 { 5960 INIT_LIST_HEAD(&tr->func_probes); 5961 INIT_LIST_HEAD(&tr->mod_trace); 5962 INIT_LIST_HEAD(&tr->mod_notrace); 5963 } 5964 #else 5965 5966 static struct ftrace_ops global_ops = { 5967 .func = ftrace_stub, 5968 .flags = FTRACE_OPS_FL_RECURSION_SAFE | 5969 FTRACE_OPS_FL_INITIALIZED | 5970 FTRACE_OPS_FL_PID, 5971 }; 5972 5973 static int __init ftrace_nodyn_init(void) 5974 { 5975 ftrace_enabled = 1; 5976 return 0; 5977 } 5978 core_initcall(ftrace_nodyn_init); 5979 5980 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; } 5981 static inline void ftrace_startup_enable(int command) { } 5982 static inline void ftrace_startup_all(int command) { } 5983 /* Keep as macros so we do not need to define the commands */ 5984 # define ftrace_startup(ops, command) \ 5985 ({ \ 5986 int ___ret = __register_ftrace_function(ops); \ 5987 if (!___ret) \ 5988 (ops)->flags |= FTRACE_OPS_FL_ENABLED; \ 5989 ___ret; \ 5990 }) 5991 # define ftrace_shutdown(ops, command) \ 5992 ({ \ 5993 int ___ret = __unregister_ftrace_function(ops); \ 5994 if (!___ret) \ 5995 (ops)->flags &= ~FTRACE_OPS_FL_ENABLED; \ 5996 ___ret; \ 5997 }) 5998 5999 # define ftrace_startup_sysctl() do { } while (0) 6000 # define ftrace_shutdown_sysctl() do { } while (0) 6001 6002 static inline int 6003 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) 6004 { 6005 return 1; 6006 } 6007 6008 static void ftrace_update_trampoline(struct ftrace_ops *ops) 6009 { 6010 } 6011 6012 #endif /* CONFIG_DYNAMIC_FTRACE */ 6013 6014 __init void ftrace_init_global_array_ops(struct trace_array *tr) 6015 { 6016 tr->ops = &global_ops; 6017 tr->ops->private = tr; 6018 ftrace_init_trace_array(tr); 6019 } 6020 6021 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func) 6022 { 6023 /* If we filter on pids, update to use the pid function */ 6024 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) { 6025 if (WARN_ON(tr->ops->func != ftrace_stub)) 6026 printk("ftrace ops had %pS for function\n", 6027 tr->ops->func); 6028 } 6029 tr->ops->func = func; 6030 tr->ops->private = tr; 6031 } 6032 6033 void ftrace_reset_array_ops(struct trace_array *tr) 6034 { 6035 tr->ops->func = ftrace_stub; 6036 } 6037 6038 static inline void 6039 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, 6040 struct ftrace_ops *ignored, struct pt_regs *regs) 6041 { 6042 struct ftrace_ops *op; 6043 int bit; 6044 6045 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); 6046 if (bit < 0) 6047 return; 6048 6049 /* 6050 * Some of the ops may be dynamically allocated, 6051 * they must be freed after a synchronize_sched(). 6052 */ 6053 preempt_disable_notrace(); 6054 6055 do_for_each_ftrace_op(op, ftrace_ops_list) { 6056 /* 6057 * Check the following for each ops before calling their func: 6058 * if RCU flag is set, then rcu_is_watching() must be true 6059 * if PER_CPU is set, then ftrace_function_local_disable() 6060 * must be false 6061 * Otherwise test if the ip matches the ops filter 6062 * 6063 * If any of the above fails then the op->func() is not executed. 6064 */ 6065 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) && 6066 (!(op->flags & FTRACE_OPS_FL_PER_CPU) || 6067 !ftrace_function_local_disabled(op)) && 6068 ftrace_ops_test(op, ip, regs)) { 6069 6070 if (FTRACE_WARN_ON(!op->func)) { 6071 pr_warn("op=%p %pS\n", op, op); 6072 goto out; 6073 } 6074 op->func(ip, parent_ip, op, regs); 6075 } 6076 } while_for_each_ftrace_op(op); 6077 out: 6078 preempt_enable_notrace(); 6079 trace_clear_recursion(bit); 6080 } 6081 6082 /* 6083 * Some archs only support passing ip and parent_ip. Even though 6084 * the list function ignores the op parameter, we do not want any 6085 * C side effects, where a function is called without the caller 6086 * sending a third parameter. 6087 * Archs are to support both the regs and ftrace_ops at the same time. 6088 * If they support ftrace_ops, it is assumed they support regs. 6089 * If call backs want to use regs, they must either check for regs 6090 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS. 6091 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved. 6092 * An architecture can pass partial regs with ftrace_ops and still 6093 * set the ARCH_SUPPORTS_FTRACE_OPS. 6094 */ 6095 #if ARCH_SUPPORTS_FTRACE_OPS 6096 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, 6097 struct ftrace_ops *op, struct pt_regs *regs) 6098 { 6099 __ftrace_ops_list_func(ip, parent_ip, NULL, regs); 6100 } 6101 #else 6102 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip) 6103 { 6104 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL); 6105 } 6106 #endif 6107 6108 /* 6109 * If there's only one function registered but it does not support 6110 * recursion, needs RCU protection and/or requires per cpu handling, then 6111 * this function will be called by the mcount trampoline. 6112 */ 6113 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip, 6114 struct ftrace_ops *op, struct pt_regs *regs) 6115 { 6116 int bit; 6117 6118 if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching()) 6119 return; 6120 6121 bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); 6122 if (bit < 0) 6123 return; 6124 6125 preempt_disable_notrace(); 6126 6127 if (!(op->flags & FTRACE_OPS_FL_PER_CPU) || 6128 !ftrace_function_local_disabled(op)) { 6129 op->func(ip, parent_ip, op, regs); 6130 } 6131 6132 preempt_enable_notrace(); 6133 trace_clear_recursion(bit); 6134 } 6135 6136 /** 6137 * ftrace_ops_get_func - get the function a trampoline should call 6138 * @ops: the ops to get the function for 6139 * 6140 * Normally the mcount trampoline will call the ops->func, but there 6141 * are times that it should not. For example, if the ops does not 6142 * have its own recursion protection, then it should call the 6143 * ftrace_ops_assist_func() instead. 6144 * 6145 * Returns the function that the trampoline should call for @ops. 6146 */ 6147 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops) 6148 { 6149 /* 6150 * If the function does not handle recursion, needs to be RCU safe, 6151 * or does per cpu logic, then we need to call the assist handler. 6152 */ 6153 if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) || 6154 ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU)) 6155 return ftrace_ops_assist_func; 6156 6157 return ops->func; 6158 } 6159 6160 static void 6161 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt, 6162 struct task_struct *prev, struct task_struct *next) 6163 { 6164 struct trace_array *tr = data; 6165 struct trace_pid_list *pid_list; 6166 6167 pid_list = rcu_dereference_sched(tr->function_pids); 6168 6169 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid, 6170 trace_ignore_this_task(pid_list, next)); 6171 } 6172 6173 static void 6174 ftrace_pid_follow_sched_process_fork(void *data, 6175 struct task_struct *self, 6176 struct task_struct *task) 6177 { 6178 struct trace_pid_list *pid_list; 6179 struct trace_array *tr = data; 6180 6181 pid_list = rcu_dereference_sched(tr->function_pids); 6182 trace_filter_add_remove_task(pid_list, self, task); 6183 } 6184 6185 static void 6186 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task) 6187 { 6188 struct trace_pid_list *pid_list; 6189 struct trace_array *tr = data; 6190 6191 pid_list = rcu_dereference_sched(tr->function_pids); 6192 trace_filter_add_remove_task(pid_list, NULL, task); 6193 } 6194 6195 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable) 6196 { 6197 if (enable) { 6198 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork, 6199 tr); 6200 register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit, 6201 tr); 6202 } else { 6203 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork, 6204 tr); 6205 unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit, 6206 tr); 6207 } 6208 } 6209 6210 static void clear_ftrace_pids(struct trace_array *tr) 6211 { 6212 struct trace_pid_list *pid_list; 6213 int cpu; 6214 6215 pid_list = rcu_dereference_protected(tr->function_pids, 6216 lockdep_is_held(&ftrace_lock)); 6217 if (!pid_list) 6218 return; 6219 6220 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr); 6221 6222 for_each_possible_cpu(cpu) 6223 per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false; 6224 6225 rcu_assign_pointer(tr->function_pids, NULL); 6226 6227 /* Wait till all users are no longer using pid filtering */ 6228 synchronize_sched(); 6229 6230 trace_free_pid_list(pid_list); 6231 } 6232 6233 void ftrace_clear_pids(struct trace_array *tr) 6234 { 6235 mutex_lock(&ftrace_lock); 6236 6237 clear_ftrace_pids(tr); 6238 6239 mutex_unlock(&ftrace_lock); 6240 } 6241 6242 static void ftrace_pid_reset(struct trace_array *tr) 6243 { 6244 mutex_lock(&ftrace_lock); 6245 clear_ftrace_pids(tr); 6246 6247 ftrace_update_pid_func(); 6248 ftrace_startup_all(0); 6249 6250 mutex_unlock(&ftrace_lock); 6251 } 6252 6253 /* Greater than any max PID */ 6254 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1) 6255 6256 static void *fpid_start(struct seq_file *m, loff_t *pos) 6257 __acquires(RCU) 6258 { 6259 struct trace_pid_list *pid_list; 6260 struct trace_array *tr = m->private; 6261 6262 mutex_lock(&ftrace_lock); 6263 rcu_read_lock_sched(); 6264 6265 pid_list = rcu_dereference_sched(tr->function_pids); 6266 6267 if (!pid_list) 6268 return !(*pos) ? FTRACE_NO_PIDS : NULL; 6269 6270 return trace_pid_start(pid_list, pos); 6271 } 6272 6273 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos) 6274 { 6275 struct trace_array *tr = m->private; 6276 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids); 6277 6278 if (v == FTRACE_NO_PIDS) 6279 return NULL; 6280 6281 return trace_pid_next(pid_list, v, pos); 6282 } 6283 6284 static void fpid_stop(struct seq_file *m, void *p) 6285 __releases(RCU) 6286 { 6287 rcu_read_unlock_sched(); 6288 mutex_unlock(&ftrace_lock); 6289 } 6290 6291 static int fpid_show(struct seq_file *m, void *v) 6292 { 6293 if (v == FTRACE_NO_PIDS) { 6294 seq_puts(m, "no pid\n"); 6295 return 0; 6296 } 6297 6298 return trace_pid_show(m, v); 6299 } 6300 6301 static const struct seq_operations ftrace_pid_sops = { 6302 .start = fpid_start, 6303 .next = fpid_next, 6304 .stop = fpid_stop, 6305 .show = fpid_show, 6306 }; 6307 6308 static int 6309 ftrace_pid_open(struct inode *inode, struct file *file) 6310 { 6311 struct trace_array *tr = inode->i_private; 6312 struct seq_file *m; 6313 int ret = 0; 6314 6315 if (trace_array_get(tr) < 0) 6316 return -ENODEV; 6317 6318 if ((file->f_mode & FMODE_WRITE) && 6319 (file->f_flags & O_TRUNC)) 6320 ftrace_pid_reset(tr); 6321 6322 ret = seq_open(file, &ftrace_pid_sops); 6323 if (ret < 0) { 6324 trace_array_put(tr); 6325 } else { 6326 m = file->private_data; 6327 /* copy tr over to seq ops */ 6328 m->private = tr; 6329 } 6330 6331 return ret; 6332 } 6333 6334 static void ignore_task_cpu(void *data) 6335 { 6336 struct trace_array *tr = data; 6337 struct trace_pid_list *pid_list; 6338 6339 /* 6340 * This function is called by on_each_cpu() while the 6341 * event_mutex is held. 6342 */ 6343 pid_list = rcu_dereference_protected(tr->function_pids, 6344 mutex_is_locked(&ftrace_lock)); 6345 6346 this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid, 6347 trace_ignore_this_task(pid_list, current)); 6348 } 6349 6350 static ssize_t 6351 ftrace_pid_write(struct file *filp, const char __user *ubuf, 6352 size_t cnt, loff_t *ppos) 6353 { 6354 struct seq_file *m = filp->private_data; 6355 struct trace_array *tr = m->private; 6356 struct trace_pid_list *filtered_pids = NULL; 6357 struct trace_pid_list *pid_list; 6358 ssize_t ret; 6359 6360 if (!cnt) 6361 return 0; 6362 6363 mutex_lock(&ftrace_lock); 6364 6365 filtered_pids = rcu_dereference_protected(tr->function_pids, 6366 lockdep_is_held(&ftrace_lock)); 6367 6368 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt); 6369 if (ret < 0) 6370 goto out; 6371 6372 rcu_assign_pointer(tr->function_pids, pid_list); 6373 6374 if (filtered_pids) { 6375 synchronize_sched(); 6376 trace_free_pid_list(filtered_pids); 6377 } else if (pid_list) { 6378 /* Register a probe to set whether to ignore the tracing of a task */ 6379 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr); 6380 } 6381 6382 /* 6383 * Ignoring of pids is done at task switch. But we have to 6384 * check for those tasks that are currently running. 6385 * Always do this in case a pid was appended or removed. 6386 */ 6387 on_each_cpu(ignore_task_cpu, tr, 1); 6388 6389 ftrace_update_pid_func(); 6390 ftrace_startup_all(0); 6391 out: 6392 mutex_unlock(&ftrace_lock); 6393 6394 if (ret > 0) 6395 *ppos += ret; 6396 6397 return ret; 6398 } 6399 6400 static int 6401 ftrace_pid_release(struct inode *inode, struct file *file) 6402 { 6403 struct trace_array *tr = inode->i_private; 6404 6405 trace_array_put(tr); 6406 6407 return seq_release(inode, file); 6408 } 6409 6410 static const struct file_operations ftrace_pid_fops = { 6411 .open = ftrace_pid_open, 6412 .write = ftrace_pid_write, 6413 .read = seq_read, 6414 .llseek = tracing_lseek, 6415 .release = ftrace_pid_release, 6416 }; 6417 6418 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer) 6419 { 6420 trace_create_file("set_ftrace_pid", 0644, d_tracer, 6421 tr, &ftrace_pid_fops); 6422 } 6423 6424 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr, 6425 struct dentry *d_tracer) 6426 { 6427 /* Only the top level directory has the dyn_tracefs and profile */ 6428 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL)); 6429 6430 ftrace_init_dyn_tracefs(d_tracer); 6431 ftrace_profile_tracefs(d_tracer); 6432 } 6433 6434 /** 6435 * ftrace_kill - kill ftrace 6436 * 6437 * This function should be used by panic code. It stops ftrace 6438 * but in a not so nice way. If you need to simply kill ftrace 6439 * from a non-atomic section, use ftrace_kill. 6440 */ 6441 void ftrace_kill(void) 6442 { 6443 ftrace_disabled = 1; 6444 ftrace_enabled = 0; 6445 clear_ftrace_function(); 6446 } 6447 6448 /** 6449 * Test if ftrace is dead or not. 6450 */ 6451 int ftrace_is_dead(void) 6452 { 6453 return ftrace_disabled; 6454 } 6455 6456 /** 6457 * register_ftrace_function - register a function for profiling 6458 * @ops - ops structure that holds the function for profiling. 6459 * 6460 * Register a function to be called by all functions in the 6461 * kernel. 6462 * 6463 * Note: @ops->func and all the functions it calls must be labeled 6464 * with "notrace", otherwise it will go into a 6465 * recursive loop. 6466 */ 6467 int register_ftrace_function(struct ftrace_ops *ops) 6468 { 6469 int ret = -1; 6470 6471 ftrace_ops_init(ops); 6472 6473 mutex_lock(&ftrace_lock); 6474 6475 ret = ftrace_startup(ops, 0); 6476 6477 mutex_unlock(&ftrace_lock); 6478 6479 return ret; 6480 } 6481 EXPORT_SYMBOL_GPL(register_ftrace_function); 6482 6483 /** 6484 * unregister_ftrace_function - unregister a function for profiling. 6485 * @ops - ops structure that holds the function to unregister 6486 * 6487 * Unregister a function that was added to be called by ftrace profiling. 6488 */ 6489 int unregister_ftrace_function(struct ftrace_ops *ops) 6490 { 6491 int ret; 6492 6493 mutex_lock(&ftrace_lock); 6494 ret = ftrace_shutdown(ops, 0); 6495 mutex_unlock(&ftrace_lock); 6496 6497 return ret; 6498 } 6499 EXPORT_SYMBOL_GPL(unregister_ftrace_function); 6500 6501 int 6502 ftrace_enable_sysctl(struct ctl_table *table, int write, 6503 void __user *buffer, size_t *lenp, 6504 loff_t *ppos) 6505 { 6506 int ret = -ENODEV; 6507 6508 mutex_lock(&ftrace_lock); 6509 6510 if (unlikely(ftrace_disabled)) 6511 goto out; 6512 6513 ret = proc_dointvec(table, write, buffer, lenp, ppos); 6514 6515 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) 6516 goto out; 6517 6518 last_ftrace_enabled = !!ftrace_enabled; 6519 6520 if (ftrace_enabled) { 6521 6522 /* we are starting ftrace again */ 6523 if (rcu_dereference_protected(ftrace_ops_list, 6524 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end) 6525 update_ftrace_function(); 6526 6527 ftrace_startup_sysctl(); 6528 6529 } else { 6530 /* stopping ftrace calls (just send to ftrace_stub) */ 6531 ftrace_trace_function = ftrace_stub; 6532 6533 ftrace_shutdown_sysctl(); 6534 } 6535 6536 out: 6537 mutex_unlock(&ftrace_lock); 6538 return ret; 6539 } 6540 6541 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 6542 6543 static struct ftrace_ops graph_ops = { 6544 .func = ftrace_stub, 6545 .flags = FTRACE_OPS_FL_RECURSION_SAFE | 6546 FTRACE_OPS_FL_INITIALIZED | 6547 FTRACE_OPS_FL_PID | 6548 FTRACE_OPS_FL_STUB, 6549 #ifdef FTRACE_GRAPH_TRAMP_ADDR 6550 .trampoline = FTRACE_GRAPH_TRAMP_ADDR, 6551 /* trampoline_size is only needed for dynamically allocated tramps */ 6552 #endif 6553 ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash) 6554 }; 6555 6556 void ftrace_graph_sleep_time_control(bool enable) 6557 { 6558 fgraph_sleep_time = enable; 6559 } 6560 6561 void ftrace_graph_graph_time_control(bool enable) 6562 { 6563 fgraph_graph_time = enable; 6564 } 6565 6566 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace) 6567 { 6568 return 0; 6569 } 6570 6571 /* The callbacks that hook a function */ 6572 trace_func_graph_ret_t ftrace_graph_return = 6573 (trace_func_graph_ret_t)ftrace_stub; 6574 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub; 6575 static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub; 6576 6577 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */ 6578 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) 6579 { 6580 int i; 6581 int ret = 0; 6582 int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE; 6583 struct task_struct *g, *t; 6584 6585 for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) { 6586 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH 6587 * sizeof(struct ftrace_ret_stack), 6588 GFP_KERNEL); 6589 if (!ret_stack_list[i]) { 6590 start = 0; 6591 end = i; 6592 ret = -ENOMEM; 6593 goto free; 6594 } 6595 } 6596 6597 read_lock(&tasklist_lock); 6598 do_each_thread(g, t) { 6599 if (start == end) { 6600 ret = -EAGAIN; 6601 goto unlock; 6602 } 6603 6604 if (t->ret_stack == NULL) { 6605 atomic_set(&t->tracing_graph_pause, 0); 6606 atomic_set(&t->trace_overrun, 0); 6607 t->curr_ret_stack = -1; 6608 /* Make sure the tasks see the -1 first: */ 6609 smp_wmb(); 6610 t->ret_stack = ret_stack_list[start++]; 6611 } 6612 } while_each_thread(g, t); 6613 6614 unlock: 6615 read_unlock(&tasklist_lock); 6616 free: 6617 for (i = start; i < end; i++) 6618 kfree(ret_stack_list[i]); 6619 return ret; 6620 } 6621 6622 static void 6623 ftrace_graph_probe_sched_switch(void *ignore, bool preempt, 6624 struct task_struct *prev, struct task_struct *next) 6625 { 6626 unsigned long long timestamp; 6627 int index; 6628 6629 /* 6630 * Does the user want to count the time a function was asleep. 6631 * If so, do not update the time stamps. 6632 */ 6633 if (fgraph_sleep_time) 6634 return; 6635 6636 timestamp = trace_clock_local(); 6637 6638 prev->ftrace_timestamp = timestamp; 6639 6640 /* only process tasks that we timestamped */ 6641 if (!next->ftrace_timestamp) 6642 return; 6643 6644 /* 6645 * Update all the counters in next to make up for the 6646 * time next was sleeping. 6647 */ 6648 timestamp -= next->ftrace_timestamp; 6649 6650 for (index = next->curr_ret_stack; index >= 0; index--) 6651 next->ret_stack[index].calltime += timestamp; 6652 } 6653 6654 /* Allocate a return stack for each task */ 6655 static int start_graph_tracing(void) 6656 { 6657 struct ftrace_ret_stack **ret_stack_list; 6658 int ret, cpu; 6659 6660 ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE * 6661 sizeof(struct ftrace_ret_stack *), 6662 GFP_KERNEL); 6663 6664 if (!ret_stack_list) 6665 return -ENOMEM; 6666 6667 /* The cpu_boot init_task->ret_stack will never be freed */ 6668 for_each_online_cpu(cpu) { 6669 if (!idle_task(cpu)->ret_stack) 6670 ftrace_graph_init_idle_task(idle_task(cpu), cpu); 6671 } 6672 6673 do { 6674 ret = alloc_retstack_tasklist(ret_stack_list); 6675 } while (ret == -EAGAIN); 6676 6677 if (!ret) { 6678 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); 6679 if (ret) 6680 pr_info("ftrace_graph: Couldn't activate tracepoint" 6681 " probe to kernel_sched_switch\n"); 6682 } 6683 6684 kfree(ret_stack_list); 6685 return ret; 6686 } 6687 6688 /* 6689 * Hibernation protection. 6690 * The state of the current task is too much unstable during 6691 * suspend/restore to disk. We want to protect against that. 6692 */ 6693 static int 6694 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state, 6695 void *unused) 6696 { 6697 switch (state) { 6698 case PM_HIBERNATION_PREPARE: 6699 pause_graph_tracing(); 6700 break; 6701 6702 case PM_POST_HIBERNATION: 6703 unpause_graph_tracing(); 6704 break; 6705 } 6706 return NOTIFY_DONE; 6707 } 6708 6709 static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace) 6710 { 6711 if (!ftrace_ops_test(&global_ops, trace->func, NULL)) 6712 return 0; 6713 return __ftrace_graph_entry(trace); 6714 } 6715 6716 /* 6717 * The function graph tracer should only trace the functions defined 6718 * by set_ftrace_filter and set_ftrace_notrace. If another function 6719 * tracer ops is registered, the graph tracer requires testing the 6720 * function against the global ops, and not just trace any function 6721 * that any ftrace_ops registered. 6722 */ 6723 static void update_function_graph_func(void) 6724 { 6725 struct ftrace_ops *op; 6726 bool do_test = false; 6727 6728 /* 6729 * The graph and global ops share the same set of functions 6730 * to test. If any other ops is on the list, then 6731 * the graph tracing needs to test if its the function 6732 * it should call. 6733 */ 6734 do_for_each_ftrace_op(op, ftrace_ops_list) { 6735 if (op != &global_ops && op != &graph_ops && 6736 op != &ftrace_list_end) { 6737 do_test = true; 6738 /* in double loop, break out with goto */ 6739 goto out; 6740 } 6741 } while_for_each_ftrace_op(op); 6742 out: 6743 if (do_test) 6744 ftrace_graph_entry = ftrace_graph_entry_test; 6745 else 6746 ftrace_graph_entry = __ftrace_graph_entry; 6747 } 6748 6749 static struct notifier_block ftrace_suspend_notifier = { 6750 .notifier_call = ftrace_suspend_notifier_call, 6751 }; 6752 6753 int register_ftrace_graph(trace_func_graph_ret_t retfunc, 6754 trace_func_graph_ent_t entryfunc) 6755 { 6756 int ret = 0; 6757 6758 mutex_lock(&ftrace_lock); 6759 6760 /* we currently allow only one tracer registered at a time */ 6761 if (ftrace_graph_active) { 6762 ret = -EBUSY; 6763 goto out; 6764 } 6765 6766 register_pm_notifier(&ftrace_suspend_notifier); 6767 6768 ftrace_graph_active++; 6769 ret = start_graph_tracing(); 6770 if (ret) { 6771 ftrace_graph_active--; 6772 goto out; 6773 } 6774 6775 ftrace_graph_return = retfunc; 6776 6777 /* 6778 * Update the indirect function to the entryfunc, and the 6779 * function that gets called to the entry_test first. Then 6780 * call the update fgraph entry function to determine if 6781 * the entryfunc should be called directly or not. 6782 */ 6783 __ftrace_graph_entry = entryfunc; 6784 ftrace_graph_entry = ftrace_graph_entry_test; 6785 update_function_graph_func(); 6786 6787 ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET); 6788 out: 6789 mutex_unlock(&ftrace_lock); 6790 return ret; 6791 } 6792 6793 void unregister_ftrace_graph(void) 6794 { 6795 mutex_lock(&ftrace_lock); 6796 6797 if (unlikely(!ftrace_graph_active)) 6798 goto out; 6799 6800 ftrace_graph_active--; 6801 ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub; 6802 ftrace_graph_entry = ftrace_graph_entry_stub; 6803 __ftrace_graph_entry = ftrace_graph_entry_stub; 6804 ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET); 6805 unregister_pm_notifier(&ftrace_suspend_notifier); 6806 unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); 6807 6808 out: 6809 mutex_unlock(&ftrace_lock); 6810 } 6811 6812 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack); 6813 6814 static void 6815 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack) 6816 { 6817 atomic_set(&t->tracing_graph_pause, 0); 6818 atomic_set(&t->trace_overrun, 0); 6819 t->ftrace_timestamp = 0; 6820 /* make curr_ret_stack visible before we add the ret_stack */ 6821 smp_wmb(); 6822 t->ret_stack = ret_stack; 6823 } 6824 6825 /* 6826 * Allocate a return stack for the idle task. May be the first 6827 * time through, or it may be done by CPU hotplug online. 6828 */ 6829 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) 6830 { 6831 t->curr_ret_stack = -1; 6832 /* 6833 * The idle task has no parent, it either has its own 6834 * stack or no stack at all. 6835 */ 6836 if (t->ret_stack) 6837 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu)); 6838 6839 if (ftrace_graph_active) { 6840 struct ftrace_ret_stack *ret_stack; 6841 6842 ret_stack = per_cpu(idle_ret_stack, cpu); 6843 if (!ret_stack) { 6844 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH 6845 * sizeof(struct ftrace_ret_stack), 6846 GFP_KERNEL); 6847 if (!ret_stack) 6848 return; 6849 per_cpu(idle_ret_stack, cpu) = ret_stack; 6850 } 6851 graph_init_task(t, ret_stack); 6852 } 6853 } 6854 6855 /* Allocate a return stack for newly created task */ 6856 void ftrace_graph_init_task(struct task_struct *t) 6857 { 6858 /* Make sure we do not use the parent ret_stack */ 6859 t->ret_stack = NULL; 6860 t->curr_ret_stack = -1; 6861 6862 if (ftrace_graph_active) { 6863 struct ftrace_ret_stack *ret_stack; 6864 6865 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH 6866 * sizeof(struct ftrace_ret_stack), 6867 GFP_KERNEL); 6868 if (!ret_stack) 6869 return; 6870 graph_init_task(t, ret_stack); 6871 } 6872 } 6873 6874 void ftrace_graph_exit_task(struct task_struct *t) 6875 { 6876 struct ftrace_ret_stack *ret_stack = t->ret_stack; 6877 6878 t->ret_stack = NULL; 6879 /* NULL must become visible to IRQs before we free it: */ 6880 barrier(); 6881 6882 kfree(ret_stack); 6883 } 6884 #endif 6885