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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 | /* * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 1999, 2000, 06 Ralf Baechle (ralf@linux-mips.org) * Copyright (C) 1999, 2000 Silicon Graphics, Inc. */ #ifndef _ASM_SPINLOCK_H #define _ASM_SPINLOCK_H #include <asm/barrier.h> #include <asm/war.h> /* * Your basic SMP spinlocks, allowing only a single CPU anywhere */ #define __raw_spin_is_locked(x) ((x)->lock != 0) #define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock) #define __raw_spin_unlock_wait(x) \ do { cpu_relax(); } while ((x)->lock) /* * Simple spin lock operations. There are two variants, one clears IRQ's * on the local processor, one does not. * * We make no fairness assumptions. They have a cost. */ static inline void __raw_spin_lock(raw_spinlock_t *lock) { unsigned int tmp; if (R10000_LLSC_WAR) { __asm__ __volatile__( " .set noreorder # __raw_spin_lock \n" "1: ll %1, %2 \n" " bnez %1, 1b \n" " li %1, 1 \n" " sc %1, %0 \n" " beqzl %1, 1b \n" " nop \n" " .set reorder \n" : "=m" (lock->lock), "=&r" (tmp) : "m" (lock->lock) : "memory"); } else { __asm__ __volatile__( " .set noreorder # __raw_spin_lock \n" "1: ll %1, %2 \n" " bnez %1, 2f \n" " li %1, 1 \n" " sc %1, %0 \n" " beqz %1, 2f \n" " nop \n" " .subsection 2 \n" "2: ll %1, %2 \n" " bnez %1, 2b \n" " li %1, 1 \n" " b 1b \n" " nop \n" " .previous \n" " .set reorder \n" : "=m" (lock->lock), "=&r" (tmp) : "m" (lock->lock) : "memory"); } smp_llsc_mb(); } static inline void __raw_spin_unlock(raw_spinlock_t *lock) { smp_mb(); __asm__ __volatile__( " .set noreorder # __raw_spin_unlock \n" " sw $0, %0 \n" " .set\treorder \n" : "=m" (lock->lock) : "m" (lock->lock) : "memory"); } static inline unsigned int __raw_spin_trylock(raw_spinlock_t *lock) { unsigned int temp, res; if (R10000_LLSC_WAR) { __asm__ __volatile__( " .set noreorder # __raw_spin_trylock \n" "1: ll %0, %3 \n" " ori %2, %0, 1 \n" " sc %2, %1 \n" " beqzl %2, 1b \n" " nop \n" " andi %2, %0, 1 \n" " .set reorder" : "=&r" (temp), "=m" (lock->lock), "=&r" (res) : "m" (lock->lock) : "memory"); } else { __asm__ __volatile__( " .set noreorder # __raw_spin_trylock \n" "1: ll %0, %3 \n" " ori %2, %0, 1 \n" " sc %2, %1 \n" " beqz %2, 2f \n" " andi %2, %0, 1 \n" " .subsection 2 \n" "2: b 1b \n" " nop \n" " .previous \n" " .set reorder" : "=&r" (temp), "=m" (lock->lock), "=&r" (res) : "m" (lock->lock) : "memory"); } smp_llsc_mb(); return res == 0; } /* * Read-write spinlocks, allowing multiple readers but only one writer. * * NOTE! it is quite common to have readers in interrupts but no interrupt * writers. For those circumstances we can "mix" irq-safe locks - any writer * needs to get a irq-safe write-lock, but readers can get non-irqsafe * read-locks. */ /* * read_can_lock - would read_trylock() succeed? * @lock: the rwlock in question. */ #define __raw_read_can_lock(rw) ((rw)->lock >= 0) /* * write_can_lock - would write_trylock() succeed? * @lock: the rwlock in question. */ #define __raw_write_can_lock(rw) (!(rw)->lock) static inline void __raw_read_lock(raw_rwlock_t *rw) { unsigned int tmp; if (R10000_LLSC_WAR) { __asm__ __volatile__( " .set noreorder # __raw_read_lock \n" "1: ll %1, %2 \n" " bltz %1, 1b \n" " addu %1, 1 \n" " sc %1, %0 \n" " beqzl %1, 1b \n" " nop \n" " .set reorder \n" : "=m" (rw->lock), "=&r" (tmp) : "m" (rw->lock) : "memory"); } else { __asm__ __volatile__( " .set noreorder # __raw_read_lock \n" "1: ll %1, %2 \n" " bltz %1, 2f \n" " addu %1, 1 \n" " sc %1, %0 \n" " beqz %1, 1b \n" " nop \n" " .subsection 2 \n" "2: ll %1, %2 \n" " bltz %1, 2b \n" " addu %1, 1 \n" " b 1b \n" " nop \n" " .previous \n" " .set reorder \n" : "=m" (rw->lock), "=&r" (tmp) : "m" (rw->lock) : "memory"); } smp_llsc_mb(); } /* Note the use of sub, not subu which will make the kernel die with an overflow exception if we ever try to unlock an rwlock that is already unlocked or is being held by a writer. */ static inline void __raw_read_unlock(raw_rwlock_t *rw) { unsigned int tmp; smp_llsc_mb(); if (R10000_LLSC_WAR) { __asm__ __volatile__( "1: ll %1, %2 # __raw_read_unlock \n" " sub %1, 1 \n" " sc %1, %0 \n" " beqzl %1, 1b \n" : "=m" (rw->lock), "=&r" (tmp) : "m" (rw->lock) : "memory"); } else { __asm__ __volatile__( " .set noreorder # __raw_read_unlock \n" "1: ll %1, %2 \n" " sub %1, 1 \n" " sc %1, %0 \n" " beqz %1, 2f \n" " nop \n" " .subsection 2 \n" "2: b 1b \n" " nop \n" " .previous \n" " .set reorder \n" : "=m" (rw->lock), "=&r" (tmp) : "m" (rw->lock) : "memory"); } } static inline void __raw_write_lock(raw_rwlock_t *rw) { unsigned int tmp; if (R10000_LLSC_WAR) { __asm__ __volatile__( " .set noreorder # __raw_write_lock \n" "1: ll %1, %2 \n" " bnez %1, 1b \n" " lui %1, 0x8000 \n" " sc %1, %0 \n" " beqzl %1, 1b \n" " nop \n" " .set reorder \n" : "=m" (rw->lock), "=&r" (tmp) : "m" (rw->lock) : "memory"); } else { __asm__ __volatile__( " .set noreorder # __raw_write_lock \n" "1: ll %1, %2 \n" " bnez %1, 2f \n" " lui %1, 0x8000 \n" " sc %1, %0 \n" " beqz %1, 2f \n" " nop \n" " .subsection 2 \n" "2: ll %1, %2 \n" " bnez %1, 2b \n" " lui %1, 0x8000 \n" " b 1b \n" " nop \n" " .previous \n" " .set reorder \n" : "=m" (rw->lock), "=&r" (tmp) : "m" (rw->lock) : "memory"); } smp_llsc_mb(); } static inline void __raw_write_unlock(raw_rwlock_t *rw) { smp_mb(); __asm__ __volatile__( " # __raw_write_unlock \n" " sw $0, %0 \n" : "=m" (rw->lock) : "m" (rw->lock) : "memory"); } static inline int __raw_read_trylock(raw_rwlock_t *rw) { unsigned int tmp; int ret; if (R10000_LLSC_WAR) { __asm__ __volatile__( " .set noreorder # __raw_read_trylock \n" " li %2, 0 \n" "1: ll %1, %3 \n" " bltz %1, 2f \n" " addu %1, 1 \n" " sc %1, %0 \n" " .set reorder \n" " beqzl %1, 1b \n" " nop \n" __WEAK_LLSC_MB " li %2, 1 \n" "2: \n" : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret) : "m" (rw->lock) : "memory"); } else { __asm__ __volatile__( " .set noreorder # __raw_read_trylock \n" " li %2, 0 \n" "1: ll %1, %3 \n" " bltz %1, 2f \n" " addu %1, 1 \n" " sc %1, %0 \n" " beqz %1, 1b \n" " nop \n" " .set reorder \n" __WEAK_LLSC_MB " li %2, 1 \n" "2: \n" : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret) : "m" (rw->lock) : "memory"); } return ret; } static inline int __raw_write_trylock(raw_rwlock_t *rw) { unsigned int tmp; int ret; if (R10000_LLSC_WAR) { __asm__ __volatile__( " .set noreorder # __raw_write_trylock \n" " li %2, 0 \n" "1: ll %1, %3 \n" " bnez %1, 2f \n" " lui %1, 0x8000 \n" " sc %1, %0 \n" " beqzl %1, 1b \n" " nop \n" __WEAK_LLSC_MB " li %2, 1 \n" " .set reorder \n" "2: \n" : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret) : "m" (rw->lock) : "memory"); } else { __asm__ __volatile__( " .set noreorder # __raw_write_trylock \n" " li %2, 0 \n" "1: ll %1, %3 \n" " bnez %1, 2f \n" " lui %1, 0x8000 \n" " sc %1, %0 \n" " beqz %1, 3f \n" " li %2, 1 \n" "2: \n" __WEAK_LLSC_MB " .subsection 2 \n" "3: b 1b \n" " li %2, 0 \n" " .previous \n" " .set reorder \n" : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret) : "m" (rw->lock) : "memory"); } return ret; } #define _raw_spin_relax(lock) cpu_relax() #define _raw_read_relax(lock) cpu_relax() #define _raw_write_relax(lock) cpu_relax() #endif /* _ASM_SPINLOCK_H */ |