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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 | #ifndef _ASM_X86_BITOPS_H #define _ASM_X86_BITOPS_H /* * Copyright 1992, Linus Torvalds. * * Note: inlines with more than a single statement should be marked * __always_inline to avoid problems with older gcc's inlining heuristics. */ #ifndef _LINUX_BITOPS_H #error only <linux/bitops.h> can be included directly #endif #include <linux/compiler.h> #include <asm/alternative.h> /* * These have to be done with inline assembly: that way the bit-setting * is guaranteed to be atomic. All bit operations return 0 if the bit * was cleared before the operation and != 0 if it was not. * * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). */ #if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 1) /* Technically wrong, but this avoids compilation errors on some gcc versions. */ #define BITOP_ADDR(x) "=m" (*(volatile long *) (x)) #else #define BITOP_ADDR(x) "+m" (*(volatile long *) (x)) #endif #define ADDR BITOP_ADDR(addr) /* * We do the locked ops that don't return the old value as * a mask operation on a byte. */ #define IS_IMMEDIATE(nr) (__builtin_constant_p(nr)) #define CONST_MASK_ADDR(nr, addr) BITOP_ADDR((void *)(addr) + ((nr)>>3)) #define CONST_MASK(nr) (1 << ((nr) & 7)) /** * set_bit - Atomically set a bit in memory * @nr: the bit to set * @addr: the address to start counting from * * This function is atomic and may not be reordered. See __set_bit() * if you do not require the atomic guarantees. * * Note: there are no guarantees that this function will not be reordered * on non x86 architectures, so if you are writing portable code, * make sure not to rely on its reordering guarantees. * * Note that @nr may be almost arbitrarily large; this function is not * restricted to acting on a single-word quantity. */ static __always_inline void set_bit(unsigned int nr, volatile unsigned long *addr) { if (IS_IMMEDIATE(nr)) { asm volatile(LOCK_PREFIX "orb %1,%0" : CONST_MASK_ADDR(nr, addr) : "iq" ((u8)CONST_MASK(nr)) : "memory"); } else { asm volatile(LOCK_PREFIX "bts %1,%0" : BITOP_ADDR(addr) : "Ir" (nr) : "memory"); } } /** * __set_bit - Set a bit in memory * @nr: the bit to set * @addr: the address to start counting from * * Unlike set_bit(), this function is non-atomic and may be reordered. * If it's called on the same region of memory simultaneously, the effect * may be that only one operation succeeds. */ static inline void __set_bit(int nr, volatile unsigned long *addr) { asm volatile("bts %1,%0" : ADDR : "Ir" (nr) : "memory"); } /** * clear_bit - Clears a bit in memory * @nr: Bit to clear * @addr: Address to start counting from * * clear_bit() is atomic and may not be reordered. However, it does * not contain a memory barrier, so if it is used for locking purposes, * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit() * in order to ensure changes are visible on other processors. */ static __always_inline void clear_bit(int nr, volatile unsigned long *addr) { if (IS_IMMEDIATE(nr)) { asm volatile(LOCK_PREFIX "andb %1,%0" : CONST_MASK_ADDR(nr, addr) : "iq" ((u8)~CONST_MASK(nr))); } else { asm volatile(LOCK_PREFIX "btr %1,%0" : BITOP_ADDR(addr) : "Ir" (nr)); } } /* * clear_bit_unlock - Clears a bit in memory * @nr: Bit to clear * @addr: Address to start counting from * * clear_bit() is atomic and implies release semantics before the memory * operation. It can be used for an unlock. */ static inline void clear_bit_unlock(unsigned nr, volatile unsigned long *addr) { barrier(); clear_bit(nr, addr); } static inline void __clear_bit(int nr, volatile unsigned long *addr) { asm volatile("btr %1,%0" : ADDR : "Ir" (nr)); } /* * __clear_bit_unlock - Clears a bit in memory * @nr: Bit to clear * @addr: Address to start counting from * * __clear_bit() is non-atomic and implies release semantics before the memory * operation. It can be used for an unlock if no other CPUs can concurrently * modify other bits in the word. * * No memory barrier is required here, because x86 cannot reorder stores past * older loads. Same principle as spin_unlock. */ static inline void __clear_bit_unlock(unsigned nr, volatile unsigned long *addr) { barrier(); __clear_bit(nr, addr); } #define smp_mb__before_clear_bit() barrier() #define smp_mb__after_clear_bit() barrier() /** * __change_bit - Toggle a bit in memory * @nr: the bit to change * @addr: the address to start counting from * * Unlike change_bit(), this function is non-atomic and may be reordered. * If it's called on the same region of memory simultaneously, the effect * may be that only one operation succeeds. */ static inline void __change_bit(int nr, volatile unsigned long *addr) { asm volatile("btc %1,%0" : ADDR : "Ir" (nr)); } /** * change_bit - Toggle a bit in memory * @nr: Bit to change * @addr: Address to start counting from * * change_bit() is atomic and may not be reordered. * Note that @nr may be almost arbitrarily large; this function is not * restricted to acting on a single-word quantity. */ static inline void change_bit(int nr, volatile unsigned long *addr) { if (IS_IMMEDIATE(nr)) { asm volatile(LOCK_PREFIX "xorb %1,%0" : CONST_MASK_ADDR(nr, addr) : "iq" ((u8)CONST_MASK(nr))); } else { asm volatile(LOCK_PREFIX "btc %1,%0" : BITOP_ADDR(addr) : "Ir" (nr)); } } /** * test_and_set_bit - Set a bit and return its old value * @nr: Bit to set * @addr: Address to count from * * This operation is atomic and cannot be reordered. * It also implies a memory barrier. */ static inline int test_and_set_bit(int nr, volatile unsigned long *addr) { int oldbit; asm volatile(LOCK_PREFIX "bts %2,%1\n\t" "sbb %0,%0" : "=r" (oldbit), ADDR : "Ir" (nr) : "memory"); return oldbit; } /** * test_and_set_bit_lock - Set a bit and return its old value for lock * @nr: Bit to set * @addr: Address to count from * * This is the same as test_and_set_bit on x86. */ static __always_inline int test_and_set_bit_lock(int nr, volatile unsigned long *addr) { return test_and_set_bit(nr, addr); } /** * __test_and_set_bit - Set a bit and return its old value * @nr: Bit to set * @addr: Address to count from * * This operation is non-atomic and can be reordered. * If two examples of this operation race, one can appear to succeed * but actually fail. You must protect multiple accesses with a lock. */ static inline int __test_and_set_bit(int nr, volatile unsigned long *addr) { int oldbit; asm("bts %2,%1\n\t" "sbb %0,%0" : "=r" (oldbit), ADDR : "Ir" (nr)); return oldbit; } /** * test_and_clear_bit - Clear a bit and return its old value * @nr: Bit to clear * @addr: Address to count from * * This operation is atomic and cannot be reordered. * It also implies a memory barrier. */ static inline int test_and_clear_bit(int nr, volatile unsigned long *addr) { int oldbit; asm volatile(LOCK_PREFIX "btr %2,%1\n\t" "sbb %0,%0" : "=r" (oldbit), ADDR : "Ir" (nr) : "memory"); return oldbit; } /** * __test_and_clear_bit - Clear a bit and return its old value * @nr: Bit to clear * @addr: Address to count from * * This operation is non-atomic and can be reordered. * If two examples of this operation race, one can appear to succeed * but actually fail. You must protect multiple accesses with a lock. */ static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr) { int oldbit; asm volatile("btr %2,%1\n\t" "sbb %0,%0" : "=r" (oldbit), ADDR : "Ir" (nr)); return oldbit; } /* WARNING: non atomic and it can be reordered! */ static inline int __test_and_change_bit(int nr, volatile unsigned long *addr) { int oldbit; asm volatile("btc %2,%1\n\t" "sbb %0,%0" : "=r" (oldbit), ADDR : "Ir" (nr) : "memory"); return oldbit; } /** * test_and_change_bit - Change a bit and return its old value * @nr: Bit to change * @addr: Address to count from * * This operation is atomic and cannot be reordered. * It also implies a memory barrier. */ static inline int test_and_change_bit(int nr, volatile unsigned long *addr) { int oldbit; asm volatile(LOCK_PREFIX "btc %2,%1\n\t" "sbb %0,%0" : "=r" (oldbit), ADDR : "Ir" (nr) : "memory"); return oldbit; } static __always_inline int constant_test_bit(unsigned int nr, const volatile unsigned long *addr) { return ((1UL << (nr % BITS_PER_LONG)) & (((unsigned long *)addr)[nr / BITS_PER_LONG])) != 0; } static inline int variable_test_bit(int nr, volatile const unsigned long *addr) { int oldbit; asm volatile("bt %2,%1\n\t" "sbb %0,%0" : "=r" (oldbit) : "m" (*(unsigned long *)addr), "Ir" (nr)); return oldbit; } #if 0 /* Fool kernel-doc since it doesn't do macros yet */ /** * test_bit - Determine whether a bit is set * @nr: bit number to test * @addr: Address to start counting from */ static int test_bit(int nr, const volatile unsigned long *addr); #endif #define test_bit(nr, addr) \ (__builtin_constant_p((nr)) \ ? constant_test_bit((nr), (addr)) \ : variable_test_bit((nr), (addr))) /** * __ffs - find first set bit in word * @word: The word to search * * Undefined if no bit exists, so code should check against 0 first. */ static inline unsigned long __ffs(unsigned long word) { asm("bsf %1,%0" : "=r" (word) : "rm" (word)); return word; } /** * ffz - find first zero bit in word * @word: The word to search * * Undefined if no zero exists, so code should check against ~0UL first. */ static inline unsigned long ffz(unsigned long word) { asm("bsf %1,%0" : "=r" (word) : "r" (~word)); return word; } /* * __fls: find last set bit in word * @word: The word to search * * Undefined if no set bit exists, so code should check against 0 first. */ static inline unsigned long __fls(unsigned long word) { asm("bsr %1,%0" : "=r" (word) : "rm" (word)); return word; } #ifdef __KERNEL__ /** * ffs - find first set bit in word * @x: the word to search * * This is defined the same way as the libc and compiler builtin ffs * routines, therefore differs in spirit from the other bitops. * * ffs(value) returns 0 if value is 0 or the position of the first * set bit if value is nonzero. The first (least significant) bit * is at position 1. */ static inline int ffs(int x) { int r; #ifdef CONFIG_X86_CMOV asm("bsfl %1,%0\n\t" "cmovzl %2,%0" : "=r" (r) : "rm" (x), "r" (-1)); #else asm("bsfl %1,%0\n\t" "jnz 1f\n\t" "movl $-1,%0\n" "1:" : "=r" (r) : "rm" (x)); #endif return r + 1; } /** * fls - find last set bit in word * @x: the word to search * * This is defined in a similar way as the libc and compiler builtin * ffs, but returns the position of the most significant set bit. * * fls(value) returns 0 if value is 0 or the position of the last * set bit if value is nonzero. The last (most significant) bit is * at position 32. */ static inline int fls(int x) { int r; #ifdef CONFIG_X86_CMOV asm("bsrl %1,%0\n\t" "cmovzl %2,%0" : "=&r" (r) : "rm" (x), "rm" (-1)); #else asm("bsrl %1,%0\n\t" "jnz 1f\n\t" "movl $-1,%0\n" "1:" : "=r" (r) : "rm" (x)); #endif return r + 1; } #endif /* __KERNEL__ */ #undef ADDR #ifdef __KERNEL__ #include <asm-generic/bitops/sched.h> #define ARCH_HAS_FAST_MULTIPLIER 1 #include <asm-generic/bitops/hweight.h> #endif /* __KERNEL__ */ #include <asm-generic/bitops/fls64.h> #ifdef __KERNEL__ #include <asm-generic/bitops/ext2-non-atomic.h> #define ext2_set_bit_atomic(lock, nr, addr) \ test_and_set_bit((nr), (unsigned long *)(addr)) #define ext2_clear_bit_atomic(lock, nr, addr) \ test_and_clear_bit((nr), (unsigned long *)(addr)) #include <asm-generic/bitops/minix.h> #endif /* __KERNEL__ */ #endif /* _ASM_X86_BITOPS_H */ |