| 1 | /* |
| 2 | * Copyright (2004) Linus Torvalds |
| 3 | * |
| 4 | * Author: Zwane Mwaikambo <zwane@fsmlabs.com> |
| 5 | * |
| 6 | * Copyright (2004, 2005) Ingo Molnar |
| 7 | * |
| 8 | * This file contains the spinlock/rwlock implementations for the |
| 9 | * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them) |
| 10 | * |
| 11 | * Note that some architectures have special knowledge about the |
| 12 | * stack frames of these functions in their profile_pc. If you |
| 13 | * change anything significant here that could change the stack |
| 14 | * frame contact the architecture maintainers. |
| 15 | */ |
| 16 | |
| 17 | #include <linux/linkage.h> |
| 18 | #include <linux/preempt.h> |
| 19 | #include <linux/spinlock.h> |
| 20 | #include <linux/interrupt.h> |
| 21 | #include <linux/debug_locks.h> |
| 22 | #include <linux/module.h> |
| 23 | |
| 24 | int __lockfunc _spin_trylock(spinlock_t *lock) |
| 25 | { |
| 26 | preempt_disable(); |
| 27 | if (_raw_spin_trylock(lock)) { |
| 28 | spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); |
| 29 | return 1; |
| 30 | } |
| 31 | |
| 32 | preempt_enable(); |
| 33 | return 0; |
| 34 | } |
| 35 | EXPORT_SYMBOL(_spin_trylock); |
| 36 | |
| 37 | int __lockfunc _read_trylock(rwlock_t *lock) |
| 38 | { |
| 39 | preempt_disable(); |
| 40 | if (_raw_read_trylock(lock)) { |
| 41 | rwlock_acquire_read(&lock->dep_map, 0, 1, _RET_IP_); |
| 42 | return 1; |
| 43 | } |
| 44 | |
| 45 | preempt_enable(); |
| 46 | return 0; |
| 47 | } |
| 48 | EXPORT_SYMBOL(_read_trylock); |
| 49 | |
| 50 | int __lockfunc _write_trylock(rwlock_t *lock) |
| 51 | { |
| 52 | preempt_disable(); |
| 53 | if (_raw_write_trylock(lock)) { |
| 54 | rwlock_acquire(&lock->dep_map, 0, 1, _RET_IP_); |
| 55 | return 1; |
| 56 | } |
| 57 | |
| 58 | preempt_enable(); |
| 59 | return 0; |
| 60 | } |
| 61 | EXPORT_SYMBOL(_write_trylock); |
| 62 | |
| 63 | /* |
| 64 | * If lockdep is enabled then we use the non-preemption spin-ops |
| 65 | * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are |
| 66 | * not re-enabled during lock-acquire (which the preempt-spin-ops do): |
| 67 | */ |
| 68 | #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC) |
| 69 | |
| 70 | void __lockfunc _read_lock(rwlock_t *lock) |
| 71 | { |
| 72 | preempt_disable(); |
| 73 | rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_); |
| 74 | LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock); |
| 75 | } |
| 76 | EXPORT_SYMBOL(_read_lock); |
| 77 | |
| 78 | unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock) |
| 79 | { |
| 80 | unsigned long flags; |
| 81 | |
| 82 | local_irq_save(flags); |
| 83 | preempt_disable(); |
| 84 | spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); |
| 85 | /* |
| 86 | * On lockdep we dont want the hand-coded irq-enable of |
| 87 | * _raw_spin_lock_flags() code, because lockdep assumes |
| 88 | * that interrupts are not re-enabled during lock-acquire: |
| 89 | */ |
| 90 | #ifdef CONFIG_LOCKDEP |
| 91 | LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); |
| 92 | #else |
| 93 | _raw_spin_lock_flags(lock, &flags); |
| 94 | #endif |
| 95 | return flags; |
| 96 | } |
| 97 | EXPORT_SYMBOL(_spin_lock_irqsave); |
| 98 | |
| 99 | void __lockfunc _spin_lock_irq(spinlock_t *lock) |
| 100 | { |
| 101 | local_irq_disable(); |
| 102 | preempt_disable(); |
| 103 | spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); |
| 104 | LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); |
| 105 | } |
| 106 | EXPORT_SYMBOL(_spin_lock_irq); |
| 107 | |
| 108 | void __lockfunc _spin_lock_bh(spinlock_t *lock) |
| 109 | { |
| 110 | local_bh_disable(); |
| 111 | preempt_disable(); |
| 112 | spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); |
| 113 | LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); |
| 114 | } |
| 115 | EXPORT_SYMBOL(_spin_lock_bh); |
| 116 | |
| 117 | unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock) |
| 118 | { |
| 119 | unsigned long flags; |
| 120 | |
| 121 | local_irq_save(flags); |
| 122 | preempt_disable(); |
| 123 | rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_); |
| 124 | LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock); |
| 125 | return flags; |
| 126 | } |
| 127 | EXPORT_SYMBOL(_read_lock_irqsave); |
| 128 | |
| 129 | void __lockfunc _read_lock_irq(rwlock_t *lock) |
| 130 | { |
| 131 | local_irq_disable(); |
| 132 | preempt_disable(); |
| 133 | rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_); |
| 134 | LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock); |
| 135 | } |
| 136 | EXPORT_SYMBOL(_read_lock_irq); |
| 137 | |
| 138 | void __lockfunc _read_lock_bh(rwlock_t *lock) |
| 139 | { |
| 140 | local_bh_disable(); |
| 141 | preempt_disable(); |
| 142 | rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_); |
| 143 | LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock); |
| 144 | } |
| 145 | EXPORT_SYMBOL(_read_lock_bh); |
| 146 | |
| 147 | unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock) |
| 148 | { |
| 149 | unsigned long flags; |
| 150 | |
| 151 | local_irq_save(flags); |
| 152 | preempt_disable(); |
| 153 | rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_); |
| 154 | LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock); |
| 155 | return flags; |
| 156 | } |
| 157 | EXPORT_SYMBOL(_write_lock_irqsave); |
| 158 | |
| 159 | void __lockfunc _write_lock_irq(rwlock_t *lock) |
| 160 | { |
| 161 | local_irq_disable(); |
| 162 | preempt_disable(); |
| 163 | rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_); |
| 164 | LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock); |
| 165 | } |
| 166 | EXPORT_SYMBOL(_write_lock_irq); |
| 167 | |
| 168 | void __lockfunc _write_lock_bh(rwlock_t *lock) |
| 169 | { |
| 170 | local_bh_disable(); |
| 171 | preempt_disable(); |
| 172 | rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_); |
| 173 | LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock); |
| 174 | } |
| 175 | EXPORT_SYMBOL(_write_lock_bh); |
| 176 | |
| 177 | void __lockfunc _spin_lock(spinlock_t *lock) |
| 178 | { |
| 179 | preempt_disable(); |
| 180 | spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); |
| 181 | LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); |
| 182 | } |
| 183 | |
| 184 | EXPORT_SYMBOL(_spin_lock); |
| 185 | |
| 186 | void __lockfunc _write_lock(rwlock_t *lock) |
| 187 | { |
| 188 | preempt_disable(); |
| 189 | rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_); |
| 190 | LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock); |
| 191 | } |
| 192 | |
| 193 | EXPORT_SYMBOL(_write_lock); |
| 194 | |
| 195 | #else /* CONFIG_PREEMPT: */ |
| 196 | |
| 197 | /* |
| 198 | * This could be a long-held lock. We both prepare to spin for a long |
| 199 | * time (making _this_ CPU preemptable if possible), and we also signal |
| 200 | * towards that other CPU that it should break the lock ASAP. |
| 201 | * |
| 202 | * (We do this in a function because inlining it would be excessive.) |
| 203 | */ |
| 204 | |
| 205 | #define BUILD_LOCK_OPS(op, locktype) \ |
| 206 | void __lockfunc _##op##_lock(locktype##_t *lock) \ |
| 207 | { \ |
| 208 | for (;;) { \ |
| 209 | preempt_disable(); \ |
| 210 | if (likely(_raw_##op##_trylock(lock))) \ |
| 211 | break; \ |
| 212 | preempt_enable(); \ |
| 213 | \ |
| 214 | if (!(lock)->break_lock) \ |
| 215 | (lock)->break_lock = 1; \ |
| 216 | while (!op##_can_lock(lock) && (lock)->break_lock) \ |
| 217 | _raw_##op##_relax(&lock->raw_lock); \ |
| 218 | } \ |
| 219 | (lock)->break_lock = 0; \ |
| 220 | } \ |
| 221 | \ |
| 222 | EXPORT_SYMBOL(_##op##_lock); \ |
| 223 | \ |
| 224 | unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \ |
| 225 | { \ |
| 226 | unsigned long flags; \ |
| 227 | \ |
| 228 | for (;;) { \ |
| 229 | preempt_disable(); \ |
| 230 | local_irq_save(flags); \ |
| 231 | if (likely(_raw_##op##_trylock(lock))) \ |
| 232 | break; \ |
| 233 | local_irq_restore(flags); \ |
| 234 | preempt_enable(); \ |
| 235 | \ |
| 236 | if (!(lock)->break_lock) \ |
| 237 | (lock)->break_lock = 1; \ |
| 238 | while (!op##_can_lock(lock) && (lock)->break_lock) \ |
| 239 | _raw_##op##_relax(&lock->raw_lock); \ |
| 240 | } \ |
| 241 | (lock)->break_lock = 0; \ |
| 242 | return flags; \ |
| 243 | } \ |
| 244 | \ |
| 245 | EXPORT_SYMBOL(_##op##_lock_irqsave); \ |
| 246 | \ |
| 247 | void __lockfunc _##op##_lock_irq(locktype##_t *lock) \ |
| 248 | { \ |
| 249 | _##op##_lock_irqsave(lock); \ |
| 250 | } \ |
| 251 | \ |
| 252 | EXPORT_SYMBOL(_##op##_lock_irq); \ |
| 253 | \ |
| 254 | void __lockfunc _##op##_lock_bh(locktype##_t *lock) \ |
| 255 | { \ |
| 256 | unsigned long flags; \ |
| 257 | \ |
| 258 | /* */ \ |
| 259 | /* Careful: we must exclude softirqs too, hence the */ \ |
| 260 | /* irq-disabling. We use the generic preemption-aware */ \ |
| 261 | /* function: */ \ |
| 262 | /**/ \ |
| 263 | flags = _##op##_lock_irqsave(lock); \ |
| 264 | local_bh_disable(); \ |
| 265 | local_irq_restore(flags); \ |
| 266 | } \ |
| 267 | \ |
| 268 | EXPORT_SYMBOL(_##op##_lock_bh) |
| 269 | |
| 270 | /* |
| 271 | * Build preemption-friendly versions of the following |
| 272 | * lock-spinning functions: |
| 273 | * |
| 274 | * _[spin|read|write]_lock() |
| 275 | * _[spin|read|write]_lock_irq() |
| 276 | * _[spin|read|write]_lock_irqsave() |
| 277 | * _[spin|read|write]_lock_bh() |
| 278 | */ |
| 279 | BUILD_LOCK_OPS(spin, spinlock); |
| 280 | BUILD_LOCK_OPS(read, rwlock); |
| 281 | BUILD_LOCK_OPS(write, rwlock); |
| 282 | |
| 283 | #endif /* CONFIG_PREEMPT */ |
| 284 | |
| 285 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 286 | |
| 287 | void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass) |
| 288 | { |
| 289 | preempt_disable(); |
| 290 | spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); |
| 291 | LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); |
| 292 | } |
| 293 | |
| 294 | EXPORT_SYMBOL(_spin_lock_nested); |
| 295 | unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass) |
| 296 | { |
| 297 | unsigned long flags; |
| 298 | |
| 299 | local_irq_save(flags); |
| 300 | preempt_disable(); |
| 301 | spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); |
| 302 | /* |
| 303 | * On lockdep we dont want the hand-coded irq-enable of |
| 304 | * _raw_spin_lock_flags() code, because lockdep assumes |
| 305 | * that interrupts are not re-enabled during lock-acquire: |
| 306 | */ |
| 307 | #ifdef CONFIG_LOCKDEP |
| 308 | LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); |
| 309 | #else |
| 310 | _raw_spin_lock_flags(lock, &flags); |
| 311 | #endif |
| 312 | return flags; |
| 313 | } |
| 314 | |
| 315 | EXPORT_SYMBOL(_spin_lock_irqsave_nested); |
| 316 | |
| 317 | #endif |
| 318 | |
| 319 | void __lockfunc _spin_unlock(spinlock_t *lock) |
| 320 | { |
| 321 | spin_release(&lock->dep_map, 1, _RET_IP_); |
| 322 | _raw_spin_unlock(lock); |
| 323 | preempt_enable(); |
| 324 | } |
| 325 | EXPORT_SYMBOL(_spin_unlock); |
| 326 | |
| 327 | void __lockfunc _write_unlock(rwlock_t *lock) |
| 328 | { |
| 329 | rwlock_release(&lock->dep_map, 1, _RET_IP_); |
| 330 | _raw_write_unlock(lock); |
| 331 | preempt_enable(); |
| 332 | } |
| 333 | EXPORT_SYMBOL(_write_unlock); |
| 334 | |
| 335 | void __lockfunc _read_unlock(rwlock_t *lock) |
| 336 | { |
| 337 | rwlock_release(&lock->dep_map, 1, _RET_IP_); |
| 338 | _raw_read_unlock(lock); |
| 339 | preempt_enable(); |
| 340 | } |
| 341 | EXPORT_SYMBOL(_read_unlock); |
| 342 | |
| 343 | void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) |
| 344 | { |
| 345 | spin_release(&lock->dep_map, 1, _RET_IP_); |
| 346 | _raw_spin_unlock(lock); |
| 347 | local_irq_restore(flags); |
| 348 | preempt_enable(); |
| 349 | } |
| 350 | EXPORT_SYMBOL(_spin_unlock_irqrestore); |
| 351 | |
| 352 | void __lockfunc _spin_unlock_irq(spinlock_t *lock) |
| 353 | { |
| 354 | spin_release(&lock->dep_map, 1, _RET_IP_); |
| 355 | _raw_spin_unlock(lock); |
| 356 | local_irq_enable(); |
| 357 | preempt_enable(); |
| 358 | } |
| 359 | EXPORT_SYMBOL(_spin_unlock_irq); |
| 360 | |
| 361 | void __lockfunc _spin_unlock_bh(spinlock_t *lock) |
| 362 | { |
| 363 | spin_release(&lock->dep_map, 1, _RET_IP_); |
| 364 | _raw_spin_unlock(lock); |
| 365 | preempt_enable_no_resched(); |
| 366 | local_bh_enable_ip((unsigned long)__builtin_return_address(0)); |
| 367 | } |
| 368 | EXPORT_SYMBOL(_spin_unlock_bh); |
| 369 | |
| 370 | void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags) |
| 371 | { |
| 372 | rwlock_release(&lock->dep_map, 1, _RET_IP_); |
| 373 | _raw_read_unlock(lock); |
| 374 | local_irq_restore(flags); |
| 375 | preempt_enable(); |
| 376 | } |
| 377 | EXPORT_SYMBOL(_read_unlock_irqrestore); |
| 378 | |
| 379 | void __lockfunc _read_unlock_irq(rwlock_t *lock) |
| 380 | { |
| 381 | rwlock_release(&lock->dep_map, 1, _RET_IP_); |
| 382 | _raw_read_unlock(lock); |
| 383 | local_irq_enable(); |
| 384 | preempt_enable(); |
| 385 | } |
| 386 | EXPORT_SYMBOL(_read_unlock_irq); |
| 387 | |
| 388 | void __lockfunc _read_unlock_bh(rwlock_t *lock) |
| 389 | { |
| 390 | rwlock_release(&lock->dep_map, 1, _RET_IP_); |
| 391 | _raw_read_unlock(lock); |
| 392 | preempt_enable_no_resched(); |
| 393 | local_bh_enable_ip((unsigned long)__builtin_return_address(0)); |
| 394 | } |
| 395 | EXPORT_SYMBOL(_read_unlock_bh); |
| 396 | |
| 397 | void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags) |
| 398 | { |
| 399 | rwlock_release(&lock->dep_map, 1, _RET_IP_); |
| 400 | _raw_write_unlock(lock); |
| 401 | local_irq_restore(flags); |
| 402 | preempt_enable(); |
| 403 | } |
| 404 | EXPORT_SYMBOL(_write_unlock_irqrestore); |
| 405 | |
| 406 | void __lockfunc _write_unlock_irq(rwlock_t *lock) |
| 407 | { |
| 408 | rwlock_release(&lock->dep_map, 1, _RET_IP_); |
| 409 | _raw_write_unlock(lock); |
| 410 | local_irq_enable(); |
| 411 | preempt_enable(); |
| 412 | } |
| 413 | EXPORT_SYMBOL(_write_unlock_irq); |
| 414 | |
| 415 | void __lockfunc _write_unlock_bh(rwlock_t *lock) |
| 416 | { |
| 417 | rwlock_release(&lock->dep_map, 1, _RET_IP_); |
| 418 | _raw_write_unlock(lock); |
| 419 | preempt_enable_no_resched(); |
| 420 | local_bh_enable_ip((unsigned long)__builtin_return_address(0)); |
| 421 | } |
| 422 | EXPORT_SYMBOL(_write_unlock_bh); |
| 423 | |
| 424 | int __lockfunc _spin_trylock_bh(spinlock_t *lock) |
| 425 | { |
| 426 | local_bh_disable(); |
| 427 | preempt_disable(); |
| 428 | if (_raw_spin_trylock(lock)) { |
| 429 | spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); |
| 430 | return 1; |
| 431 | } |
| 432 | |
| 433 | preempt_enable_no_resched(); |
| 434 | local_bh_enable_ip((unsigned long)__builtin_return_address(0)); |
| 435 | return 0; |
| 436 | } |
| 437 | EXPORT_SYMBOL(_spin_trylock_bh); |
| 438 | |
| 439 | int in_lock_functions(unsigned long addr) |
| 440 | { |
| 441 | /* Linker adds these: start and end of __lockfunc functions */ |
| 442 | extern char __lock_text_start[], __lock_text_end[]; |
| 443 | |
| 444 | return addr >= (unsigned long)__lock_text_start |
| 445 | && addr < (unsigned long)__lock_text_end; |
| 446 | } |
| 447 | EXPORT_SYMBOL(in_lock_functions); |