1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Runtime locking correctness validator 4 * 5 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <[email protected]> 6 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra 7 * 8 * see Documentation/locking/lockdep-design.txt for more details. 9 */ 10 #ifndef __LINUX_LOCKDEP_H 11 #define __LINUX_LOCKDEP_H 12 13 struct task_struct; 14 struct lockdep_map; 15 16 /* for sysctl */ 17 extern int prove_locking; 18 extern int lock_stat; 19 20 #define MAX_LOCKDEP_SUBCLASSES 8UL 21 22 #include <linux/types.h> 23 24 #ifdef CONFIG_LOCKDEP 25 26 #include <linux/linkage.h> 27 #include <linux/list.h> 28 #include <linux/debug_locks.h> 29 #include <linux/stacktrace.h> 30 31 /* 32 * We'd rather not expose kernel/lockdep_states.h this wide, but we do need 33 * the total number of states... :-( 34 */ 35 #define XXX_LOCK_USAGE_STATES (1+2*4) 36 37 /* 38 * NR_LOCKDEP_CACHING_CLASSES ... Number of classes 39 * cached in the instance of lockdep_map 40 * 41 * Currently main class (subclass == 0) and signle depth subclass 42 * are cached in lockdep_map. This optimization is mainly targeting 43 * on rq->lock. double_rq_lock() acquires this highly competitive with 44 * single depth. 45 */ 46 #define NR_LOCKDEP_CACHING_CLASSES 2 47 48 /* 49 * Lock-classes are keyed via unique addresses, by embedding the 50 * lockclass-key into the kernel (or module) .data section. (For 51 * static locks we use the lock address itself as the key.) 52 */ 53 struct lockdep_subclass_key { 54 char __one_byte; 55 } __attribute__ ((__packed__)); 56 57 struct lock_class_key { 58 struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES]; 59 }; 60 61 extern struct lock_class_key __lockdep_no_validate__; 62 63 #define LOCKSTAT_POINTS 4 64 65 /* 66 * The lock-class itself: 67 */ 68 struct lock_class { 69 /* 70 * class-hash: 71 */ 72 struct hlist_node hash_entry; 73 74 /* 75 * global list of all lock-classes: 76 */ 77 struct list_head lock_entry; 78 79 struct lockdep_subclass_key *key; 80 unsigned int subclass; 81 unsigned int dep_gen_id; 82 83 /* 84 * IRQ/softirq usage tracking bits: 85 */ 86 unsigned long usage_mask; 87 struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES]; 88 89 /* 90 * These fields represent a directed graph of lock dependencies, 91 * to every node we attach a list of "forward" and a list of 92 * "backward" graph nodes. 93 */ 94 struct list_head locks_after, locks_before; 95 96 /* 97 * Generation counter, when doing certain classes of graph walking, 98 * to ensure that we check one node only once: 99 */ 100 unsigned int version; 101 102 /* 103 * Statistics counter: 104 */ 105 unsigned long ops; 106 107 const char *name; 108 int name_version; 109 110 #ifdef CONFIG_LOCK_STAT 111 unsigned long contention_point[LOCKSTAT_POINTS]; 112 unsigned long contending_point[LOCKSTAT_POINTS]; 113 #endif 114 }; 115 116 #ifdef CONFIG_LOCK_STAT 117 struct lock_time { 118 s64 min; 119 s64 max; 120 s64 total; 121 unsigned long nr; 122 }; 123 124 enum bounce_type { 125 bounce_acquired_write, 126 bounce_acquired_read, 127 bounce_contended_write, 128 bounce_contended_read, 129 nr_bounce_types, 130 131 bounce_acquired = bounce_acquired_write, 132 bounce_contended = bounce_contended_write, 133 }; 134 135 struct lock_class_stats { 136 unsigned long contention_point[LOCKSTAT_POINTS]; 137 unsigned long contending_point[LOCKSTAT_POINTS]; 138 struct lock_time read_waittime; 139 struct lock_time write_waittime; 140 struct lock_time read_holdtime; 141 struct lock_time write_holdtime; 142 unsigned long bounces[nr_bounce_types]; 143 }; 144 145 struct lock_class_stats lock_stats(struct lock_class *class); 146 void clear_lock_stats(struct lock_class *class); 147 #endif 148 149 /* 150 * Map the lock object (the lock instance) to the lock-class object. 151 * This is embedded into specific lock instances: 152 */ 153 struct lockdep_map { 154 struct lock_class_key *key; 155 struct lock_class *class_cache[NR_LOCKDEP_CACHING_CLASSES]; 156 const char *name; 157 #ifdef CONFIG_LOCK_STAT 158 int cpu; 159 unsigned long ip; 160 #endif 161 }; 162 163 static inline void lockdep_copy_map(struct lockdep_map *to, 164 struct lockdep_map *from) 165 { 166 int i; 167 168 *to = *from; 169 /* 170 * Since the class cache can be modified concurrently we could observe 171 * half pointers (64bit arch using 32bit copy insns). Therefore clear 172 * the caches and take the performance hit. 173 * 174 * XXX it doesn't work well with lockdep_set_class_and_subclass(), since 175 * that relies on cache abuse. 176 */ 177 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) 178 to->class_cache[i] = NULL; 179 } 180 181 /* 182 * Every lock has a list of other locks that were taken after it. 183 * We only grow the list, never remove from it: 184 */ 185 struct lock_list { 186 struct list_head entry; 187 struct lock_class *class; 188 struct stack_trace trace; 189 int distance; 190 191 /* 192 * The parent field is used to implement breadth-first search, and the 193 * bit 0 is reused to indicate if the lock has been accessed in BFS. 194 */ 195 struct lock_list *parent; 196 }; 197 198 /* 199 * We record lock dependency chains, so that we can cache them: 200 */ 201 struct lock_chain { 202 /* see BUILD_BUG_ON()s in lookup_chain_cache() */ 203 unsigned int irq_context : 2, 204 depth : 6, 205 base : 24; 206 /* 4 byte hole */ 207 struct hlist_node entry; 208 u64 chain_key; 209 }; 210 211 #define MAX_LOCKDEP_KEYS_BITS 13 212 /* 213 * Subtract one because we offset hlock->class_idx by 1 in order 214 * to make 0 mean no class. This avoids overflowing the class_idx 215 * bitfield and hitting the BUG in hlock_class(). 216 */ 217 #define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1) 218 219 struct held_lock { 220 /* 221 * One-way hash of the dependency chain up to this point. We 222 * hash the hashes step by step as the dependency chain grows. 223 * 224 * We use it for dependency-caching and we skip detection 225 * passes and dependency-updates if there is a cache-hit, so 226 * it is absolutely critical for 100% coverage of the validator 227 * to have a unique key value for every unique dependency path 228 * that can occur in the system, to make a unique hash value 229 * as likely as possible - hence the 64-bit width. 230 * 231 * The task struct holds the current hash value (initialized 232 * with zero), here we store the previous hash value: 233 */ 234 u64 prev_chain_key; 235 unsigned long acquire_ip; 236 struct lockdep_map *instance; 237 struct lockdep_map *nest_lock; 238 #ifdef CONFIG_LOCK_STAT 239 u64 waittime_stamp; 240 u64 holdtime_stamp; 241 #endif 242 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS; 243 /* 244 * The lock-stack is unified in that the lock chains of interrupt 245 * contexts nest ontop of process context chains, but we 'separate' 246 * the hashes by starting with 0 if we cross into an interrupt 247 * context, and we also keep do not add cross-context lock 248 * dependencies - the lock usage graph walking covers that area 249 * anyway, and we'd just unnecessarily increase the number of 250 * dependencies otherwise. [Note: hardirq and softirq contexts 251 * are separated from each other too.] 252 * 253 * The following field is used to detect when we cross into an 254 * interrupt context: 255 */ 256 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */ 257 unsigned int trylock:1; /* 16 bits */ 258 259 unsigned int read:2; /* see lock_acquire() comment */ 260 unsigned int check:1; /* see lock_acquire() comment */ 261 unsigned int hardirqs_off:1; 262 unsigned int references:12; /* 32 bits */ 263 unsigned int pin_count; 264 }; 265 266 /* 267 * Initialization, self-test and debugging-output methods: 268 */ 269 extern void lockdep_init(void); 270 extern void lockdep_reset(void); 271 extern void lockdep_reset_lock(struct lockdep_map *lock); 272 extern void lockdep_free_key_range(void *start, unsigned long size); 273 extern asmlinkage void lockdep_sys_exit(void); 274 275 extern void lockdep_off(void); 276 extern void lockdep_on(void); 277 278 /* 279 * These methods are used by specific locking variants (spinlocks, 280 * rwlocks, mutexes and rwsems) to pass init/acquire/release events 281 * to lockdep: 282 */ 283 284 extern void lockdep_init_map(struct lockdep_map *lock, const char *name, 285 struct lock_class_key *key, int subclass); 286 287 /* 288 * Reinitialize a lock key - for cases where there is special locking or 289 * special initialization of locks so that the validator gets the scope 290 * of dependencies wrong: they are either too broad (they need a class-split) 291 * or they are too narrow (they suffer from a false class-split): 292 */ 293 #define lockdep_set_class(lock, key) \ 294 lockdep_init_map(&(lock)->dep_map, #key, key, 0) 295 #define lockdep_set_class_and_name(lock, key, name) \ 296 lockdep_init_map(&(lock)->dep_map, name, key, 0) 297 #define lockdep_set_class_and_subclass(lock, key, sub) \ 298 lockdep_init_map(&(lock)->dep_map, #key, key, sub) 299 #define lockdep_set_subclass(lock, sub) \ 300 lockdep_init_map(&(lock)->dep_map, #lock, \ 301 (lock)->dep_map.key, sub) 302 303 #define lockdep_set_novalidate_class(lock) \ 304 lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock) 305 /* 306 * Compare locking classes 307 */ 308 #define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key) 309 310 static inline int lockdep_match_key(struct lockdep_map *lock, 311 struct lock_class_key *key) 312 { 313 return lock->key == key; 314 } 315 316 /* 317 * Acquire a lock. 318 * 319 * Values for "read": 320 * 321 * 0: exclusive (write) acquire 322 * 1: read-acquire (no recursion allowed) 323 * 2: read-acquire with same-instance recursion allowed 324 * 325 * Values for check: 326 * 327 * 0: simple checks (freeing, held-at-exit-time, etc.) 328 * 1: full validation 329 */ 330 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass, 331 int trylock, int read, int check, 332 struct lockdep_map *nest_lock, unsigned long ip); 333 334 extern void lock_release(struct lockdep_map *lock, int nested, 335 unsigned long ip); 336 337 /* 338 * Same "read" as for lock_acquire(), except -1 means any. 339 */ 340 extern int lock_is_held_type(const struct lockdep_map *lock, int read); 341 342 static inline int lock_is_held(const struct lockdep_map *lock) 343 { 344 return lock_is_held_type(lock, -1); 345 } 346 347 #define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map) 348 #define lockdep_is_held_type(lock, r) lock_is_held_type(&(lock)->dep_map, (r)) 349 350 extern void lock_set_class(struct lockdep_map *lock, const char *name, 351 struct lock_class_key *key, unsigned int subclass, 352 unsigned long ip); 353 354 static inline void lock_set_subclass(struct lockdep_map *lock, 355 unsigned int subclass, unsigned long ip) 356 { 357 lock_set_class(lock, lock->name, lock->key, subclass, ip); 358 } 359 360 extern void lock_downgrade(struct lockdep_map *lock, unsigned long ip); 361 362 struct pin_cookie { unsigned int val; }; 363 364 #define NIL_COOKIE (struct pin_cookie){ .val = 0U, } 365 366 extern struct pin_cookie lock_pin_lock(struct lockdep_map *lock); 367 extern void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie); 368 extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); 369 370 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) 371 372 #define lockdep_assert_held(l) do { \ 373 WARN_ON(debug_locks && !lockdep_is_held(l)); \ 374 } while (0) 375 376 #define lockdep_assert_held_exclusive(l) do { \ 377 WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \ 378 } while (0) 379 380 #define lockdep_assert_held_read(l) do { \ 381 WARN_ON(debug_locks && !lockdep_is_held_type(l, 1)); \ 382 } while (0) 383 384 #define lockdep_assert_held_once(l) do { \ 385 WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \ 386 } while (0) 387 388 #define lockdep_recursing(tsk) ((tsk)->lockdep_recursion) 389 390 #define lockdep_pin_lock(l) lock_pin_lock(&(l)->dep_map) 391 #define lockdep_repin_lock(l,c) lock_repin_lock(&(l)->dep_map, (c)) 392 #define lockdep_unpin_lock(l,c) lock_unpin_lock(&(l)->dep_map, (c)) 393 394 #else /* !CONFIG_LOCKDEP */ 395 396 static inline void lockdep_off(void) 397 { 398 } 399 400 static inline void lockdep_on(void) 401 { 402 } 403 404 # define lock_acquire(l, s, t, r, c, n, i) do { } while (0) 405 # define lock_release(l, n, i) do { } while (0) 406 # define lock_downgrade(l, i) do { } while (0) 407 # define lock_set_class(l, n, k, s, i) do { } while (0) 408 # define lock_set_subclass(l, s, i) do { } while (0) 409 # define lockdep_init() do { } while (0) 410 # define lockdep_init_map(lock, name, key, sub) \ 411 do { (void)(name); (void)(key); } while (0) 412 # define lockdep_set_class(lock, key) do { (void)(key); } while (0) 413 # define lockdep_set_class_and_name(lock, key, name) \ 414 do { (void)(key); (void)(name); } while (0) 415 #define lockdep_set_class_and_subclass(lock, key, sub) \ 416 do { (void)(key); } while (0) 417 #define lockdep_set_subclass(lock, sub) do { } while (0) 418 419 #define lockdep_set_novalidate_class(lock) do { } while (0) 420 421 /* 422 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP 423 * case since the result is not well defined and the caller should rather 424 * #ifdef the call himself. 425 */ 426 427 # define lockdep_reset() do { debug_locks = 1; } while (0) 428 # define lockdep_free_key_range(start, size) do { } while (0) 429 # define lockdep_sys_exit() do { } while (0) 430 /* 431 * The class key takes no space if lockdep is disabled: 432 */ 433 struct lock_class_key { }; 434 435 /* 436 * The lockdep_map takes no space if lockdep is disabled: 437 */ 438 struct lockdep_map { }; 439 440 #define lockdep_depth(tsk) (0) 441 442 #define lockdep_is_held_type(l, r) (1) 443 444 #define lockdep_assert_held(l) do { (void)(l); } while (0) 445 #define lockdep_assert_held_exclusive(l) do { (void)(l); } while (0) 446 #define lockdep_assert_held_read(l) do { (void)(l); } while (0) 447 #define lockdep_assert_held_once(l) do { (void)(l); } while (0) 448 449 #define lockdep_recursing(tsk) (0) 450 451 struct pin_cookie { }; 452 453 #define NIL_COOKIE (struct pin_cookie){ } 454 455 #define lockdep_pin_lock(l) ({ struct pin_cookie cookie; cookie; }) 456 #define lockdep_repin_lock(l, c) do { (void)(l); (void)(c); } while (0) 457 #define lockdep_unpin_lock(l, c) do { (void)(l); (void)(c); } while (0) 458 459 #endif /* !LOCKDEP */ 460 461 enum xhlock_context_t { 462 XHLOCK_HARD, 463 XHLOCK_SOFT, 464 XHLOCK_CTX_NR, 465 }; 466 467 #define lockdep_init_map_crosslock(m, n, k, s) do {} while (0) 468 /* 469 * To initialize a lockdep_map statically use this macro. 470 * Note that _name must not be NULL. 471 */ 472 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \ 473 { .name = (_name), .key = (void *)(_key), } 474 475 static inline void lockdep_invariant_state(bool force) {} 476 static inline void lockdep_init_task(struct task_struct *task) {} 477 static inline void lockdep_free_task(struct task_struct *task) {} 478 479 #ifdef CONFIG_LOCK_STAT 480 481 extern void lock_contended(struct lockdep_map *lock, unsigned long ip); 482 extern void lock_acquired(struct lockdep_map *lock, unsigned long ip); 483 484 #define LOCK_CONTENDED(_lock, try, lock) \ 485 do { \ 486 if (!try(_lock)) { \ 487 lock_contended(&(_lock)->dep_map, _RET_IP_); \ 488 lock(_lock); \ 489 } \ 490 lock_acquired(&(_lock)->dep_map, _RET_IP_); \ 491 } while (0) 492 493 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \ 494 ({ \ 495 int ____err = 0; \ 496 if (!try(_lock)) { \ 497 lock_contended(&(_lock)->dep_map, _RET_IP_); \ 498 ____err = lock(_lock); \ 499 } \ 500 if (!____err) \ 501 lock_acquired(&(_lock)->dep_map, _RET_IP_); \ 502 ____err; \ 503 }) 504 505 #else /* CONFIG_LOCK_STAT */ 506 507 #define lock_contended(lockdep_map, ip) do {} while (0) 508 #define lock_acquired(lockdep_map, ip) do {} while (0) 509 510 #define LOCK_CONTENDED(_lock, try, lock) \ 511 lock(_lock) 512 513 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \ 514 lock(_lock) 515 516 #endif /* CONFIG_LOCK_STAT */ 517 518 #ifdef CONFIG_LOCKDEP 519 520 /* 521 * On lockdep we dont want the hand-coded irq-enable of 522 * _raw_*_lock_flags() code, because lockdep assumes 523 * that interrupts are not re-enabled during lock-acquire: 524 */ 525 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ 526 LOCK_CONTENDED((_lock), (try), (lock)) 527 528 #else /* CONFIG_LOCKDEP */ 529 530 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ 531 lockfl((_lock), (flags)) 532 533 #endif /* CONFIG_LOCKDEP */ 534 535 #ifdef CONFIG_PROVE_LOCKING 536 extern void print_irqtrace_events(struct task_struct *curr); 537 #else 538 static inline void print_irqtrace_events(struct task_struct *curr) 539 { 540 } 541 #endif 542 543 /* 544 * For trivial one-depth nesting of a lock-class, the following 545 * global define can be used. (Subsystems with multiple levels 546 * of nesting should define their own lock-nesting subclasses.) 547 */ 548 #define SINGLE_DEPTH_NESTING 1 549 550 /* 551 * Map the dependency ops to NOP or to real lockdep ops, depending 552 * on the per lock-class debug mode: 553 */ 554 555 #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) 556 #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i) 557 #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i) 558 559 #define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) 560 #define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) 561 #define spin_release(l, n, i) lock_release(l, n, i) 562 563 #define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) 564 #define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i) 565 #define rwlock_release(l, n, i) lock_release(l, n, i) 566 567 #define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) 568 #define seqcount_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i) 569 #define seqcount_release(l, n, i) lock_release(l, n, i) 570 571 #define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) 572 #define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) 573 #define mutex_release(l, n, i) lock_release(l, n, i) 574 575 #define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) 576 #define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) 577 #define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i) 578 #define rwsem_release(l, n, i) lock_release(l, n, i) 579 580 #define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_) 581 #define lock_map_acquire_read(l) lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_) 582 #define lock_map_acquire_tryread(l) lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_) 583 #define lock_map_release(l) lock_release(l, 1, _THIS_IP_) 584 585 #ifdef CONFIG_PROVE_LOCKING 586 # define might_lock(lock) \ 587 do { \ 588 typecheck(struct lockdep_map *, &(lock)->dep_map); \ 589 lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_); \ 590 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ 591 } while (0) 592 # define might_lock_read(lock) \ 593 do { \ 594 typecheck(struct lockdep_map *, &(lock)->dep_map); \ 595 lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_); \ 596 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ 597 } while (0) 598 599 #define lockdep_assert_irqs_enabled() do { \ 600 WARN_ONCE(debug_locks && !current->lockdep_recursion && \ 601 !current->hardirqs_enabled, \ 602 "IRQs not enabled as expected\n"); \ 603 } while (0) 604 605 #define lockdep_assert_irqs_disabled() do { \ 606 WARN_ONCE(debug_locks && !current->lockdep_recursion && \ 607 current->hardirqs_enabled, \ 608 "IRQs not disabled as expected\n"); \ 609 } while (0) 610 611 #else 612 # define might_lock(lock) do { } while (0) 613 # define might_lock_read(lock) do { } while (0) 614 # define lockdep_assert_irqs_enabled() do { } while (0) 615 # define lockdep_assert_irqs_disabled() do { } while (0) 616 #endif 617 618 #ifdef CONFIG_LOCKDEP 619 void lockdep_rcu_suspicious(const char *file, const int line, const char *s); 620 #else 621 static inline void 622 lockdep_rcu_suspicious(const char *file, const int line, const char *s) 623 { 624 } 625 #endif 626 627 #endif /* __LINUX_LOCKDEP_H */ 628