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