| 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 | return __spin_trylock(lock); |
| 27 | } |
| 28 | EXPORT_SYMBOL(_spin_trylock); |
| 29 | |
| 30 | int __lockfunc _read_trylock(rwlock_t *lock) |
| 31 | { |
| 32 | return __read_trylock(lock); |
| 33 | } |
| 34 | EXPORT_SYMBOL(_read_trylock); |
| 35 | |
| 36 | int __lockfunc _write_trylock(rwlock_t *lock) |
| 37 | { |
| 38 | return __write_trylock(lock); |
| 39 | } |
| 40 | EXPORT_SYMBOL(_write_trylock); |
| 41 | |
| 42 | /* |
| 43 | * If lockdep is enabled then we use the non-preemption spin-ops |
| 44 | * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are |
| 45 | * not re-enabled during lock-acquire (which the preempt-spin-ops do): |
| 46 | */ |
| 47 | #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC) |
| 48 | |
| 49 | void __lockfunc _read_lock(rwlock_t *lock) |
| 50 | { |
| 51 | __read_lock(lock); |
| 52 | } |
| 53 | EXPORT_SYMBOL(_read_lock); |
| 54 | |
| 55 | unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock) |
| 56 | { |
| 57 | return __spin_lock_irqsave(lock); |
| 58 | } |
| 59 | EXPORT_SYMBOL(_spin_lock_irqsave); |
| 60 | |
| 61 | void __lockfunc _spin_lock_irq(spinlock_t *lock) |
| 62 | { |
| 63 | __spin_lock_irq(lock); |
| 64 | } |
| 65 | EXPORT_SYMBOL(_spin_lock_irq); |
| 66 | |
| 67 | void __lockfunc _spin_lock_bh(spinlock_t *lock) |
| 68 | { |
| 69 | __spin_lock_bh(lock); |
| 70 | } |
| 71 | EXPORT_SYMBOL(_spin_lock_bh); |
| 72 | |
| 73 | unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock) |
| 74 | { |
| 75 | return __read_lock_irqsave(lock); |
| 76 | } |
| 77 | EXPORT_SYMBOL(_read_lock_irqsave); |
| 78 | |
| 79 | void __lockfunc _read_lock_irq(rwlock_t *lock) |
| 80 | { |
| 81 | __read_lock_irq(lock); |
| 82 | } |
| 83 | EXPORT_SYMBOL(_read_lock_irq); |
| 84 | |
| 85 | void __lockfunc _read_lock_bh(rwlock_t *lock) |
| 86 | { |
| 87 | __read_lock_bh(lock); |
| 88 | } |
| 89 | EXPORT_SYMBOL(_read_lock_bh); |
| 90 | |
| 91 | unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock) |
| 92 | { |
| 93 | return __write_lock_irqsave(lock); |
| 94 | } |
| 95 | EXPORT_SYMBOL(_write_lock_irqsave); |
| 96 | |
| 97 | void __lockfunc _write_lock_irq(rwlock_t *lock) |
| 98 | { |
| 99 | __write_lock_irq(lock); |
| 100 | } |
| 101 | EXPORT_SYMBOL(_write_lock_irq); |
| 102 | |
| 103 | void __lockfunc _write_lock_bh(rwlock_t *lock) |
| 104 | { |
| 105 | __write_lock_bh(lock); |
| 106 | } |
| 107 | EXPORT_SYMBOL(_write_lock_bh); |
| 108 | |
| 109 | void __lockfunc _spin_lock(spinlock_t *lock) |
| 110 | { |
| 111 | __spin_lock(lock); |
| 112 | } |
| 113 | EXPORT_SYMBOL(_spin_lock); |
| 114 | |
| 115 | void __lockfunc _write_lock(rwlock_t *lock) |
| 116 | { |
| 117 | __write_lock(lock); |
| 118 | } |
| 119 | EXPORT_SYMBOL(_write_lock); |
| 120 | |
| 121 | #else /* CONFIG_PREEMPT: */ |
| 122 | |
| 123 | /* |
| 124 | * This could be a long-held lock. We both prepare to spin for a long |
| 125 | * time (making _this_ CPU preemptable if possible), and we also signal |
| 126 | * towards that other CPU that it should break the lock ASAP. |
| 127 | * |
| 128 | * (We do this in a function because inlining it would be excessive.) |
| 129 | */ |
| 130 | |
| 131 | #define BUILD_LOCK_OPS(op, locktype) \ |
| 132 | void __lockfunc _##op##_lock(locktype##_t *lock) \ |
| 133 | { \ |
| 134 | for (;;) { \ |
| 135 | preempt_disable(); \ |
| 136 | if (likely(_raw_##op##_trylock(lock))) \ |
| 137 | break; \ |
| 138 | preempt_enable(); \ |
| 139 | \ |
| 140 | if (!(lock)->break_lock) \ |
| 141 | (lock)->break_lock = 1; \ |
| 142 | while (!op##_can_lock(lock) && (lock)->break_lock) \ |
| 143 | _raw_##op##_relax(&lock->raw_lock); \ |
| 144 | } \ |
| 145 | (lock)->break_lock = 0; \ |
| 146 | } \ |
| 147 | \ |
| 148 | EXPORT_SYMBOL(_##op##_lock); \ |
| 149 | \ |
| 150 | unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \ |
| 151 | { \ |
| 152 | unsigned long flags; \ |
| 153 | \ |
| 154 | for (;;) { \ |
| 155 | preempt_disable(); \ |
| 156 | local_irq_save(flags); \ |
| 157 | if (likely(_raw_##op##_trylock(lock))) \ |
| 158 | break; \ |
| 159 | local_irq_restore(flags); \ |
| 160 | preempt_enable(); \ |
| 161 | \ |
| 162 | if (!(lock)->break_lock) \ |
| 163 | (lock)->break_lock = 1; \ |
| 164 | while (!op##_can_lock(lock) && (lock)->break_lock) \ |
| 165 | _raw_##op##_relax(&lock->raw_lock); \ |
| 166 | } \ |
| 167 | (lock)->break_lock = 0; \ |
| 168 | return flags; \ |
| 169 | } \ |
| 170 | \ |
| 171 | EXPORT_SYMBOL(_##op##_lock_irqsave); \ |
| 172 | \ |
| 173 | void __lockfunc _##op##_lock_irq(locktype##_t *lock) \ |
| 174 | { \ |
| 175 | _##op##_lock_irqsave(lock); \ |
| 176 | } \ |
| 177 | \ |
| 178 | EXPORT_SYMBOL(_##op##_lock_irq); \ |
| 179 | \ |
| 180 | void __lockfunc _##op##_lock_bh(locktype##_t *lock) \ |
| 181 | { \ |
| 182 | unsigned long flags; \ |
| 183 | \ |
| 184 | /* */ \ |
| 185 | /* Careful: we must exclude softirqs too, hence the */ \ |
| 186 | /* irq-disabling. We use the generic preemption-aware */ \ |
| 187 | /* function: */ \ |
| 188 | /**/ \ |
| 189 | flags = _##op##_lock_irqsave(lock); \ |
| 190 | local_bh_disable(); \ |
| 191 | local_irq_restore(flags); \ |
| 192 | } \ |
| 193 | \ |
| 194 | EXPORT_SYMBOL(_##op##_lock_bh) |
| 195 | |
| 196 | /* |
| 197 | * Build preemption-friendly versions of the following |
| 198 | * lock-spinning functions: |
| 199 | * |
| 200 | * _[spin|read|write]_lock() |
| 201 | * _[spin|read|write]_lock_irq() |
| 202 | * _[spin|read|write]_lock_irqsave() |
| 203 | * _[spin|read|write]_lock_bh() |
| 204 | */ |
| 205 | BUILD_LOCK_OPS(spin, spinlock); |
| 206 | BUILD_LOCK_OPS(read, rwlock); |
| 207 | BUILD_LOCK_OPS(write, rwlock); |
| 208 | |
| 209 | #endif /* CONFIG_PREEMPT */ |
| 210 | |
| 211 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 212 | |
| 213 | void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass) |
| 214 | { |
| 215 | preempt_disable(); |
| 216 | spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); |
| 217 | LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); |
| 218 | } |
| 219 | EXPORT_SYMBOL(_spin_lock_nested); |
| 220 | |
| 221 | unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass) |
| 222 | { |
| 223 | unsigned long flags; |
| 224 | |
| 225 | local_irq_save(flags); |
| 226 | preempt_disable(); |
| 227 | spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); |
| 228 | LOCK_CONTENDED_FLAGS(lock, _raw_spin_trylock, _raw_spin_lock, |
| 229 | _raw_spin_lock_flags, &flags); |
| 230 | return flags; |
| 231 | } |
| 232 | EXPORT_SYMBOL(_spin_lock_irqsave_nested); |
| 233 | |
| 234 | void __lockfunc _spin_lock_nest_lock(spinlock_t *lock, |
| 235 | struct lockdep_map *nest_lock) |
| 236 | { |
| 237 | preempt_disable(); |
| 238 | spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_); |
| 239 | LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); |
| 240 | } |
| 241 | EXPORT_SYMBOL(_spin_lock_nest_lock); |
| 242 | |
| 243 | #endif |
| 244 | |
| 245 | void __lockfunc _spin_unlock(spinlock_t *lock) |
| 246 | { |
| 247 | __spin_unlock(lock); |
| 248 | } |
| 249 | EXPORT_SYMBOL(_spin_unlock); |
| 250 | |
| 251 | void __lockfunc _write_unlock(rwlock_t *lock) |
| 252 | { |
| 253 | __write_unlock(lock); |
| 254 | } |
| 255 | EXPORT_SYMBOL(_write_unlock); |
| 256 | |
| 257 | void __lockfunc _read_unlock(rwlock_t *lock) |
| 258 | { |
| 259 | __read_unlock(lock); |
| 260 | } |
| 261 | EXPORT_SYMBOL(_read_unlock); |
| 262 | |
| 263 | void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) |
| 264 | { |
| 265 | __spin_unlock_irqrestore(lock, flags); |
| 266 | } |
| 267 | EXPORT_SYMBOL(_spin_unlock_irqrestore); |
| 268 | |
| 269 | void __lockfunc _spin_unlock_irq(spinlock_t *lock) |
| 270 | { |
| 271 | __spin_unlock_irq(lock); |
| 272 | } |
| 273 | EXPORT_SYMBOL(_spin_unlock_irq); |
| 274 | |
| 275 | void __lockfunc _spin_unlock_bh(spinlock_t *lock) |
| 276 | { |
| 277 | __spin_unlock_bh(lock); |
| 278 | } |
| 279 | EXPORT_SYMBOL(_spin_unlock_bh); |
| 280 | |
| 281 | void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags) |
| 282 | { |
| 283 | __read_unlock_irqrestore(lock, flags); |
| 284 | } |
| 285 | EXPORT_SYMBOL(_read_unlock_irqrestore); |
| 286 | |
| 287 | void __lockfunc _read_unlock_irq(rwlock_t *lock) |
| 288 | { |
| 289 | __read_unlock_irq(lock); |
| 290 | } |
| 291 | EXPORT_SYMBOL(_read_unlock_irq); |
| 292 | |
| 293 | void __lockfunc _read_unlock_bh(rwlock_t *lock) |
| 294 | { |
| 295 | __read_unlock_bh(lock); |
| 296 | } |
| 297 | EXPORT_SYMBOL(_read_unlock_bh); |
| 298 | |
| 299 | void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags) |
| 300 | { |
| 301 | __write_unlock_irqrestore(lock, flags); |
| 302 | } |
| 303 | EXPORT_SYMBOL(_write_unlock_irqrestore); |
| 304 | |
| 305 | void __lockfunc _write_unlock_irq(rwlock_t *lock) |
| 306 | { |
| 307 | __write_unlock_irq(lock); |
| 308 | } |
| 309 | EXPORT_SYMBOL(_write_unlock_irq); |
| 310 | |
| 311 | void __lockfunc _write_unlock_bh(rwlock_t *lock) |
| 312 | { |
| 313 | __write_unlock_bh(lock); |
| 314 | } |
| 315 | EXPORT_SYMBOL(_write_unlock_bh); |
| 316 | |
| 317 | int __lockfunc _spin_trylock_bh(spinlock_t *lock) |
| 318 | { |
| 319 | return __spin_trylock_bh(lock); |
| 320 | } |
| 321 | EXPORT_SYMBOL(_spin_trylock_bh); |
| 322 | |
| 323 | notrace int in_lock_functions(unsigned long addr) |
| 324 | { |
| 325 | /* Linker adds these: start and end of __lockfunc functions */ |
| 326 | extern char __lock_text_start[], __lock_text_end[]; |
| 327 | |
| 328 | return addr >= (unsigned long)__lock_text_start |
| 329 | && addr < (unsigned long)__lock_text_end; |
| 330 | } |
| 331 | EXPORT_SYMBOL(in_lock_functions); |