1 /* 2 * Runtime locking correctness validator 3 * 4 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <[email protected]> 5 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <[email protected]> 6 * 7 * see Documentation/lockdep-design.txt for more details. 8 */ 9 #ifndef __LINUX_LOCKDEP_H 10 #define __LINUX_LOCKDEP_H 11 12 struct task_struct; 13 struct lockdep_map; 14 15 /* for sysctl */ 16 extern int prove_locking; 17 extern int lock_stat; 18 19 #ifdef CONFIG_LOCKDEP 20 21 #include <linux/linkage.h> 22 #include <linux/list.h> 23 #include <linux/debug_locks.h> 24 #include <linux/stacktrace.h> 25 26 /* 27 * We'd rather not expose kernel/lockdep_states.h this wide, but we do need 28 * the total number of states... :-( 29 */ 30 #define XXX_LOCK_USAGE_STATES (1+3*4) 31 32 #define MAX_LOCKDEP_SUBCLASSES 8UL 33 34 /* 35 * Lock-classes are keyed via unique addresses, by embedding the 36 * lockclass-key into the kernel (or module) .data section. (For 37 * static locks we use the lock address itself as the key.) 38 */ 39 struct lockdep_subclass_key { 40 char __one_byte; 41 } __attribute__ ((__packed__)); 42 43 struct lock_class_key { 44 struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES]; 45 }; 46 47 extern struct lock_class_key __lockdep_no_validate__; 48 49 #define LOCKSTAT_POINTS 4 50 51 /* 52 * The lock-class itself: 53 */ 54 struct lock_class { 55 /* 56 * class-hash: 57 */ 58 struct list_head hash_entry; 59 60 /* 61 * global list of all lock-classes: 62 */ 63 struct list_head lock_entry; 64 65 struct lockdep_subclass_key *key; 66 unsigned int subclass; 67 unsigned int dep_gen_id; 68 69 /* 70 * IRQ/softirq usage tracking bits: 71 */ 72 unsigned long usage_mask; 73 struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES]; 74 75 /* 76 * These fields represent a directed graph of lock dependencies, 77 * to every node we attach a list of "forward" and a list of 78 * "backward" graph nodes. 79 */ 80 struct list_head locks_after, locks_before; 81 82 /* 83 * Generation counter, when doing certain classes of graph walking, 84 * to ensure that we check one node only once: 85 */ 86 unsigned int version; 87 88 /* 89 * Statistics counter: 90 */ 91 unsigned long ops; 92 93 const char *name; 94 int name_version; 95 96 #ifdef CONFIG_LOCK_STAT 97 unsigned long contention_point[LOCKSTAT_POINTS]; 98 unsigned long contending_point[LOCKSTAT_POINTS]; 99 #endif 100 }; 101 102 #ifdef CONFIG_LOCK_STAT 103 struct lock_time { 104 s64 min; 105 s64 max; 106 s64 total; 107 unsigned long nr; 108 }; 109 110 enum bounce_type { 111 bounce_acquired_write, 112 bounce_acquired_read, 113 bounce_contended_write, 114 bounce_contended_read, 115 nr_bounce_types, 116 117 bounce_acquired = bounce_acquired_write, 118 bounce_contended = bounce_contended_write, 119 }; 120 121 struct lock_class_stats { 122 unsigned long contention_point[4]; 123 unsigned long contending_point[4]; 124 struct lock_time read_waittime; 125 struct lock_time write_waittime; 126 struct lock_time read_holdtime; 127 struct lock_time write_holdtime; 128 unsigned long bounces[nr_bounce_types]; 129 }; 130 131 struct lock_class_stats lock_stats(struct lock_class *class); 132 void clear_lock_stats(struct lock_class *class); 133 #endif 134 135 /* 136 * Map the lock object (the lock instance) to the lock-class object. 137 * This is embedded into specific lock instances: 138 */ 139 struct lockdep_map { 140 struct lock_class_key *key; 141 struct lock_class *class_cache; 142 const char *name; 143 #ifdef CONFIG_LOCK_STAT 144 int cpu; 145 unsigned long ip; 146 #endif 147 }; 148 149 /* 150 * Every lock has a list of other locks that were taken after it. 151 * We only grow the list, never remove from it: 152 */ 153 struct lock_list { 154 struct list_head entry; 155 struct lock_class *class; 156 struct stack_trace trace; 157 int distance; 158 159 /* 160 * The parent field is used to implement breadth-first search, and the 161 * bit 0 is reused to indicate if the lock has been accessed in BFS. 162 */ 163 struct lock_list *parent; 164 }; 165 166 /* 167 * We record lock dependency chains, so that we can cache them: 168 */ 169 struct lock_chain { 170 u8 irq_context; 171 u8 depth; 172 u16 base; 173 struct list_head entry; 174 u64 chain_key; 175 }; 176 177 #define MAX_LOCKDEP_KEYS_BITS 13 178 /* 179 * Subtract one because we offset hlock->class_idx by 1 in order 180 * to make 0 mean no class. This avoids overflowing the class_idx 181 * bitfield and hitting the BUG in hlock_class(). 182 */ 183 #define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1) 184 185 struct held_lock { 186 /* 187 * One-way hash of the dependency chain up to this point. We 188 * hash the hashes step by step as the dependency chain grows. 189 * 190 * We use it for dependency-caching and we skip detection 191 * passes and dependency-updates if there is a cache-hit, so 192 * it is absolutely critical for 100% coverage of the validator 193 * to have a unique key value for every unique dependency path 194 * that can occur in the system, to make a unique hash value 195 * as likely as possible - hence the 64-bit width. 196 * 197 * The task struct holds the current hash value (initialized 198 * with zero), here we store the previous hash value: 199 */ 200 u64 prev_chain_key; 201 unsigned long acquire_ip; 202 struct lockdep_map *instance; 203 struct lockdep_map *nest_lock; 204 #ifdef CONFIG_LOCK_STAT 205 u64 waittime_stamp; 206 u64 holdtime_stamp; 207 #endif 208 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS; 209 /* 210 * The lock-stack is unified in that the lock chains of interrupt 211 * contexts nest ontop of process context chains, but we 'separate' 212 * the hashes by starting with 0 if we cross into an interrupt 213 * context, and we also keep do not add cross-context lock 214 * dependencies - the lock usage graph walking covers that area 215 * anyway, and we'd just unnecessarily increase the number of 216 * dependencies otherwise. [Note: hardirq and softirq contexts 217 * are separated from each other too.] 218 * 219 * The following field is used to detect when we cross into an 220 * interrupt context: 221 */ 222 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */ 223 unsigned int trylock:1; /* 16 bits */ 224 225 unsigned int read:2; /* see lock_acquire() comment */ 226 unsigned int check:2; /* see lock_acquire() comment */ 227 unsigned int hardirqs_off:1; 228 unsigned int references:11; /* 32 bits */ 229 }; 230 231 /* 232 * Initialization, self-test and debugging-output methods: 233 */ 234 extern void lockdep_init(void); 235 extern void lockdep_info(void); 236 extern void lockdep_reset(void); 237 extern void lockdep_reset_lock(struct lockdep_map *lock); 238 extern void lockdep_free_key_range(void *start, unsigned long size); 239 extern void lockdep_sys_exit(void); 240 241 extern void lockdep_off(void); 242 extern void lockdep_on(void); 243 244 /* 245 * These methods are used by specific locking variants (spinlocks, 246 * rwlocks, mutexes and rwsems) to pass init/acquire/release events 247 * to lockdep: 248 */ 249 250 extern void lockdep_init_map(struct lockdep_map *lock, const char *name, 251 struct lock_class_key *key, int subclass); 252 253 /* 254 * To initialize a lockdep_map statically use this macro. 255 * Note that _name must not be NULL. 256 */ 257 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \ 258 { .name = (_name), .key = (void *)(_key), } 259 260 /* 261 * Reinitialize a lock key - for cases where there is special locking or 262 * special initialization of locks so that the validator gets the scope 263 * of dependencies wrong: they are either too broad (they need a class-split) 264 * or they are too narrow (they suffer from a false class-split): 265 */ 266 #define lockdep_set_class(lock, key) \ 267 lockdep_init_map(&(lock)->dep_map, #key, key, 0) 268 #define lockdep_set_class_and_name(lock, key, name) \ 269 lockdep_init_map(&(lock)->dep_map, name, key, 0) 270 #define lockdep_set_class_and_subclass(lock, key, sub) \ 271 lockdep_init_map(&(lock)->dep_map, #key, key, sub) 272 #define lockdep_set_subclass(lock, sub) \ 273 lockdep_init_map(&(lock)->dep_map, #lock, \ 274 (lock)->dep_map.key, sub) 275 276 #define lockdep_set_novalidate_class(lock) \ 277 lockdep_set_class(lock, &__lockdep_no_validate__) 278 /* 279 * Compare locking classes 280 */ 281 #define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key) 282 283 static inline int lockdep_match_key(struct lockdep_map *lock, 284 struct lock_class_key *key) 285 { 286 return lock->key == key; 287 } 288 289 /* 290 * Acquire a lock. 291 * 292 * Values for "read": 293 * 294 * 0: exclusive (write) acquire 295 * 1: read-acquire (no recursion allowed) 296 * 2: read-acquire with same-instance recursion allowed 297 * 298 * Values for check: 299 * 300 * 0: disabled 301 * 1: simple checks (freeing, held-at-exit-time, etc.) 302 * 2: full validation 303 */ 304 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass, 305 int trylock, int read, int check, 306 struct lockdep_map *nest_lock, unsigned long ip); 307 308 extern void lock_release(struct lockdep_map *lock, int nested, 309 unsigned long ip); 310 311 #define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map) 312 313 extern int lock_is_held(struct lockdep_map *lock); 314 315 extern void lock_set_class(struct lockdep_map *lock, const char *name, 316 struct lock_class_key *key, unsigned int subclass, 317 unsigned long ip); 318 319 static inline void lock_set_subclass(struct lockdep_map *lock, 320 unsigned int subclass, unsigned long ip) 321 { 322 lock_set_class(lock, lock->name, lock->key, subclass, ip); 323 } 324 325 extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask); 326 extern void lockdep_clear_current_reclaim_state(void); 327 extern void lockdep_trace_alloc(gfp_t mask); 328 329 # define INIT_LOCKDEP .lockdep_recursion = 0, .lockdep_reclaim_gfp = 0, 330 331 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) 332 333 #define lockdep_assert_held(l) WARN_ON(debug_locks && !lockdep_is_held(l)) 334 335 #else /* !LOCKDEP */ 336 337 static inline void lockdep_off(void) 338 { 339 } 340 341 static inline void lockdep_on(void) 342 { 343 } 344 345 # define lock_acquire(l, s, t, r, c, n, i) do { } while (0) 346 # define lock_release(l, n, i) do { } while (0) 347 # define lock_set_class(l, n, k, s, i) do { } while (0) 348 # define lock_set_subclass(l, s, i) do { } while (0) 349 # define lockdep_set_current_reclaim_state(g) do { } while (0) 350 # define lockdep_clear_current_reclaim_state() do { } while (0) 351 # define lockdep_trace_alloc(g) do { } while (0) 352 # define lockdep_init() do { } while (0) 353 # define lockdep_info() do { } while (0) 354 # define lockdep_init_map(lock, name, key, sub) \ 355 do { (void)(name); (void)(key); } while (0) 356 # define lockdep_set_class(lock, key) do { (void)(key); } while (0) 357 # define lockdep_set_class_and_name(lock, key, name) \ 358 do { (void)(key); (void)(name); } while (0) 359 #define lockdep_set_class_and_subclass(lock, key, sub) \ 360 do { (void)(key); } while (0) 361 #define lockdep_set_subclass(lock, sub) do { } while (0) 362 363 #define lockdep_set_novalidate_class(lock) do { } while (0) 364 365 /* 366 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP 367 * case since the result is not well defined and the caller should rather 368 * #ifdef the call himself. 369 */ 370 371 # define INIT_LOCKDEP 372 # define lockdep_reset() do { debug_locks = 1; } while (0) 373 # define lockdep_free_key_range(start, size) do { } while (0) 374 # define lockdep_sys_exit() do { } while (0) 375 /* 376 * The class key takes no space if lockdep is disabled: 377 */ 378 struct lock_class_key { }; 379 380 #define lockdep_depth(tsk) (0) 381 382 #define lockdep_assert_held(l) do { } while (0) 383 384 #endif /* !LOCKDEP */ 385 386 #ifdef CONFIG_LOCK_STAT 387 388 extern void lock_contended(struct lockdep_map *lock, unsigned long ip); 389 extern void lock_acquired(struct lockdep_map *lock, unsigned long ip); 390 391 #define LOCK_CONTENDED(_lock, try, lock) \ 392 do { \ 393 if (!try(_lock)) { \ 394 lock_contended(&(_lock)->dep_map, _RET_IP_); \ 395 lock(_lock); \ 396 } \ 397 lock_acquired(&(_lock)->dep_map, _RET_IP_); \ 398 } while (0) 399 400 #else /* CONFIG_LOCK_STAT */ 401 402 #define lock_contended(lockdep_map, ip) do {} while (0) 403 #define lock_acquired(lockdep_map, ip) do {} while (0) 404 405 #define LOCK_CONTENDED(_lock, try, lock) \ 406 lock(_lock) 407 408 #endif /* CONFIG_LOCK_STAT */ 409 410 #ifdef CONFIG_LOCKDEP 411 412 /* 413 * On lockdep we dont want the hand-coded irq-enable of 414 * _raw_*_lock_flags() code, because lockdep assumes 415 * that interrupts are not re-enabled during lock-acquire: 416 */ 417 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ 418 LOCK_CONTENDED((_lock), (try), (lock)) 419 420 #else /* CONFIG_LOCKDEP */ 421 422 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \ 423 lockfl((_lock), (flags)) 424 425 #endif /* CONFIG_LOCKDEP */ 426 427 #ifdef CONFIG_GENERIC_HARDIRQS 428 extern void early_init_irq_lock_class(void); 429 #else 430 static inline void early_init_irq_lock_class(void) 431 { 432 } 433 #endif 434 435 #ifdef CONFIG_TRACE_IRQFLAGS 436 extern void early_boot_irqs_off(void); 437 extern void early_boot_irqs_on(void); 438 extern void print_irqtrace_events(struct task_struct *curr); 439 #else 440 static inline void early_boot_irqs_off(void) 441 { 442 } 443 static inline void early_boot_irqs_on(void) 444 { 445 } 446 static inline void print_irqtrace_events(struct task_struct *curr) 447 { 448 } 449 #endif 450 451 /* 452 * For trivial one-depth nesting of a lock-class, the following 453 * global define can be used. (Subsystems with multiple levels 454 * of nesting should define their own lock-nesting subclasses.) 455 */ 456 #define SINGLE_DEPTH_NESTING 1 457 458 /* 459 * Map the dependency ops to NOP or to real lockdep ops, depending 460 * on the per lock-class debug mode: 461 */ 462 463 #ifdef CONFIG_DEBUG_LOCK_ALLOC 464 # ifdef CONFIG_PROVE_LOCKING 465 # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 466 # define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 2, n, i) 467 # else 468 # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 469 # define spin_acquire_nest(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, NULL, i) 470 # endif 471 # define spin_release(l, n, i) lock_release(l, n, i) 472 #else 473 # define spin_acquire(l, s, t, i) do { } while (0) 474 # define spin_release(l, n, i) do { } while (0) 475 #endif 476 477 #ifdef CONFIG_DEBUG_LOCK_ALLOC 478 # ifdef CONFIG_PROVE_LOCKING 479 # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 480 # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 2, NULL, i) 481 # else 482 # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 483 # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 1, NULL, i) 484 # endif 485 # define rwlock_release(l, n, i) lock_release(l, n, i) 486 #else 487 # define rwlock_acquire(l, s, t, i) do { } while (0) 488 # define rwlock_acquire_read(l, s, t, i) do { } while (0) 489 # define rwlock_release(l, n, i) do { } while (0) 490 #endif 491 492 #ifdef CONFIG_DEBUG_LOCK_ALLOC 493 # ifdef CONFIG_PROVE_LOCKING 494 # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 495 # else 496 # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 497 # endif 498 # define mutex_release(l, n, i) lock_release(l, n, i) 499 #else 500 # define mutex_acquire(l, s, t, i) do { } while (0) 501 # define mutex_release(l, n, i) do { } while (0) 502 #endif 503 504 #ifdef CONFIG_DEBUG_LOCK_ALLOC 505 # ifdef CONFIG_PROVE_LOCKING 506 # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, NULL, i) 507 # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, NULL, i) 508 # else 509 # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, NULL, i) 510 # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, NULL, i) 511 # endif 512 # define rwsem_release(l, n, i) lock_release(l, n, i) 513 #else 514 # define rwsem_acquire(l, s, t, i) do { } while (0) 515 # define rwsem_acquire_read(l, s, t, i) do { } while (0) 516 # define rwsem_release(l, n, i) do { } while (0) 517 #endif 518 519 #ifdef CONFIG_DEBUG_LOCK_ALLOC 520 # ifdef CONFIG_PROVE_LOCKING 521 # define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_) 522 # else 523 # define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_) 524 # endif 525 # define lock_map_release(l) lock_release(l, 1, _THIS_IP_) 526 #else 527 # define lock_map_acquire(l) do { } while (0) 528 # define lock_map_release(l) do { } while (0) 529 #endif 530 531 #ifdef CONFIG_PROVE_LOCKING 532 # define might_lock(lock) \ 533 do { \ 534 typecheck(struct lockdep_map *, &(lock)->dep_map); \ 535 lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_); \ 536 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ 537 } while (0) 538 # define might_lock_read(lock) \ 539 do { \ 540 typecheck(struct lockdep_map *, &(lock)->dep_map); \ 541 lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_); \ 542 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \ 543 } while (0) 544 #else 545 # define might_lock(lock) do { } while (0) 546 # define might_lock_read(lock) do { } while (0) 547 #endif 548 549 #ifdef CONFIG_PROVE_RCU 550 extern void lockdep_rcu_dereference(const char *file, const int line); 551 #endif 552 553 #endif /* __LINUX_LOCKDEP_H */ 554