1#ifndef _ASM_X86_BITOPS_H 2#define _ASM_X86_BITOPS_H 3 4/* 5 * Copyright 1992, Linus Torvalds. 6 * 7 * Note: inlines with more than a single statement should be marked 8 * __always_inline to avoid problems with older gcc's inlining heuristics. 9 */ 10 11#ifndef _LINUX_BITOPS_H 12#error only <linux/bitops.h> can be included directly 13#endif 14 15#include <linux/compiler.h> 16#include <asm/alternative.h> 17#include <asm/rmwcc.h> 18 19#if BITS_PER_LONG == 32 20# define _BITOPS_LONG_SHIFT 5 21#elif BITS_PER_LONG == 64 22# define _BITOPS_LONG_SHIFT 6 23#else 24# error "Unexpected BITS_PER_LONG" 25#endif 26 27#define BIT_64(n) (U64_C(1) << (n)) 28 29/* 30 * These have to be done with inline assembly: that way the bit-setting 31 * is guaranteed to be atomic. All bit operations return 0 if the bit 32 * was cleared before the operation and != 0 if it was not. 33 * 34 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). 35 */ 36 37#if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 1) 38/* Technically wrong, but this avoids compilation errors on some gcc 39 versions. */ 40#define BITOP_ADDR(x) "=m" (*(volatile long *) (x)) 41#else 42#define BITOP_ADDR(x) "+m" (*(volatile long *) (x)) 43#endif 44 45#define ADDR BITOP_ADDR(addr) 46 47/* 48 * We do the locked ops that don't return the old value as 49 * a mask operation on a byte. 50 */ 51#define IS_IMMEDIATE(nr) (__builtin_constant_p(nr)) 52#define CONST_MASK_ADDR(nr, addr) BITOP_ADDR((void *)(addr) + ((nr)>>3)) 53#define CONST_MASK(nr) (1 << ((nr) & 7)) 54 55/** 56 * set_bit - Atomically set a bit in memory 57 * @nr: the bit to set 58 * @addr: the address to start counting from 59 * 60 * This function is atomic and may not be reordered. See __set_bit() 61 * if you do not require the atomic guarantees. 62 * 63 * Note: there are no guarantees that this function will not be reordered 64 * on non x86 architectures, so if you are writing portable code, 65 * make sure not to rely on its reordering guarantees. 66 * 67 * Note that @nr may be almost arbitrarily large; this function is not 68 * restricted to acting on a single-word quantity. 69 */ 70static __always_inline void 71set_bit(long nr, volatile unsigned long *addr) 72{ 73 if (IS_IMMEDIATE(nr)) { 74 asm volatile(LOCK_PREFIX "orb %1,%0" 75 : CONST_MASK_ADDR(nr, addr) 76 : "iq" ((u8)CONST_MASK(nr)) 77 : "memory"); 78 } else { 79 asm volatile(LOCK_PREFIX "bts %1,%0" 80 : BITOP_ADDR(addr) : "Ir" (nr) : "memory"); 81 } 82} 83 84/** 85 * __set_bit - Set a bit in memory 86 * @nr: the bit to set 87 * @addr: the address to start counting from 88 * 89 * Unlike set_bit(), this function is non-atomic and may be reordered. 90 * If it's called on the same region of memory simultaneously, the effect 91 * may be that only one operation succeeds. 92 */ 93static inline void __set_bit(long nr, volatile unsigned long *addr) 94{ 95 asm volatile("bts %1,%0" : ADDR : "Ir" (nr) : "memory"); 96} 97 98/** 99 * clear_bit - Clears a bit in memory 100 * @nr: Bit to clear 101 * @addr: Address to start counting from 102 * 103 * clear_bit() is atomic and may not be reordered. However, it does 104 * not contain a memory barrier, so if it is used for locking purposes, 105 * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit() 106 * in order to ensure changes are visible on other processors. 107 */ 108static __always_inline void 109clear_bit(long nr, volatile unsigned long *addr) 110{ 111 if (IS_IMMEDIATE(nr)) { 112 asm volatile(LOCK_PREFIX "andb %1,%0" 113 : CONST_MASK_ADDR(nr, addr) 114 : "iq" ((u8)~CONST_MASK(nr))); 115 } else { 116 asm volatile(LOCK_PREFIX "btr %1,%0" 117 : BITOP_ADDR(addr) 118 : "Ir" (nr)); 119 } 120} 121 122/* 123 * clear_bit_unlock - Clears a bit in memory 124 * @nr: Bit to clear 125 * @addr: Address to start counting from 126 * 127 * clear_bit() is atomic and implies release semantics before the memory 128 * operation. It can be used for an unlock. 129 */ 130static inline void clear_bit_unlock(long nr, volatile unsigned long *addr) 131{ 132 barrier(); 133 clear_bit(nr, addr); 134} 135 136static inline void __clear_bit(long nr, volatile unsigned long *addr) 137{ 138 asm volatile("btr %1,%0" : ADDR : "Ir" (nr)); 139} 140 141/* 142 * __clear_bit_unlock - Clears a bit in memory 143 * @nr: Bit to clear 144 * @addr: Address to start counting from 145 * 146 * __clear_bit() is non-atomic and implies release semantics before the memory 147 * operation. It can be used for an unlock if no other CPUs can concurrently 148 * modify other bits in the word. 149 * 150 * No memory barrier is required here, because x86 cannot reorder stores past 151 * older loads. Same principle as spin_unlock. 152 */ 153static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr) 154{ 155 barrier(); 156 __clear_bit(nr, addr); 157} 158 159#define smp_mb__before_clear_bit() barrier() 160#define smp_mb__after_clear_bit() barrier() 161 162/** 163 * __change_bit - Toggle a bit in memory 164 * @nr: the bit to change 165 * @addr: the address to start counting from 166 * 167 * Unlike change_bit(), this function is non-atomic and may be reordered. 168 * If it's called on the same region of memory simultaneously, the effect 169 * may be that only one operation succeeds. 170 */ 171static inline void __change_bit(long nr, volatile unsigned long *addr) 172{ 173 asm volatile("btc %1,%0" : ADDR : "Ir" (nr)); 174} 175 176/** 177 * change_bit - Toggle a bit in memory 178 * @nr: Bit to change 179 * @addr: Address to start counting from 180 * 181 * change_bit() is atomic and may not be reordered. 182 * Note that @nr may be almost arbitrarily large; this function is not 183 * restricted to acting on a single-word quantity. 184 */ 185static inline void change_bit(long nr, volatile unsigned long *addr) 186{ 187 if (IS_IMMEDIATE(nr)) { 188 asm volatile(LOCK_PREFIX "xorb %1,%0" 189 : CONST_MASK_ADDR(nr, addr) 190 : "iq" ((u8)CONST_MASK(nr))); 191 } else { 192 asm volatile(LOCK_PREFIX "btc %1,%0" 193 : BITOP_ADDR(addr) 194 : "Ir" (nr)); 195 } 196} 197 198/** 199 * test_and_set_bit - Set a bit and return its old value 200 * @nr: Bit to set 201 * @addr: Address to count from 202 * 203 * This operation is atomic and cannot be reordered. 204 * It also implies a memory barrier. 205 */ 206static inline int test_and_set_bit(long nr, volatile unsigned long *addr) 207{ 208 GEN_BINARY_RMWcc(LOCK_PREFIX "bts", *addr, "Ir", nr, "%0", "c"); 209} 210 211/** 212 * test_and_set_bit_lock - Set a bit and return its old value for lock 213 * @nr: Bit to set 214 * @addr: Address to count from 215 * 216 * This is the same as test_and_set_bit on x86. 217 */ 218static __always_inline int 219test_and_set_bit_lock(long nr, volatile unsigned long *addr) 220{ 221 return test_and_set_bit(nr, addr); 222} 223 224/** 225 * __test_and_set_bit - Set a bit and return its old value 226 * @nr: Bit to set 227 * @addr: Address to count from 228 * 229 * This operation is non-atomic and can be reordered. 230 * If two examples of this operation race, one can appear to succeed 231 * but actually fail. You must protect multiple accesses with a lock. 232 */ 233static inline int __test_and_set_bit(long nr, volatile unsigned long *addr) 234{ 235 int oldbit; 236 237 asm("bts %2,%1\n\t" 238 "sbb %0,%0" 239 : "=r" (oldbit), ADDR 240 : "Ir" (nr)); 241 return oldbit; 242} 243 244/** 245 * test_and_clear_bit - Clear a bit and return its old value 246 * @nr: Bit to clear 247 * @addr: Address to count from 248 * 249 * This operation is atomic and cannot be reordered. 250 * It also implies a memory barrier. 251 */ 252static inline int test_and_clear_bit(long nr, volatile unsigned long *addr) 253{ 254 GEN_BINARY_RMWcc(LOCK_PREFIX "btr", *addr, "Ir", nr, "%0", "c"); 255} 256 257/** 258 * __test_and_clear_bit - Clear a bit and return its old value 259 * @nr: Bit to clear 260 * @addr: Address to count from 261 * 262 * This operation is non-atomic and can be reordered. 263 * If two examples of this operation race, one can appear to succeed 264 * but actually fail. You must protect multiple accesses with a lock. 265 * 266 * Note: the operation is performed atomically with respect to 267 * the local CPU, but not other CPUs. Portable code should not 268 * rely on this behaviour. 269 * KVM relies on this behaviour on x86 for modifying memory that is also 270 * accessed from a hypervisor on the same CPU if running in a VM: don't change 271 * this without also updating arch/x86/kernel/kvm.c 272 */ 273static inline int __test_and_clear_bit(long nr, volatile unsigned long *addr) 274{ 275 int oldbit; 276 277 asm volatile("btr %2,%1\n\t" 278 "sbb %0,%0" 279 : "=r" (oldbit), ADDR 280 : "Ir" (nr)); 281 return oldbit; 282} 283 284/* WARNING: non atomic and it can be reordered! */ 285static inline int __test_and_change_bit(long nr, volatile unsigned long *addr) 286{ 287 int oldbit; 288 289 asm volatile("btc %2,%1\n\t" 290 "sbb %0,%0" 291 : "=r" (oldbit), ADDR 292 : "Ir" (nr) : "memory"); 293 294 return oldbit; 295} 296 297/** 298 * test_and_change_bit - Change a bit and return its old value 299 * @nr: Bit to change 300 * @addr: Address to count from 301 * 302 * This operation is atomic and cannot be reordered. 303 * It also implies a memory barrier. 304 */ 305static inline int test_and_change_bit(long nr, volatile unsigned long *addr) 306{ 307 GEN_BINARY_RMWcc(LOCK_PREFIX "btc", *addr, "Ir", nr, "%0", "c"); 308} 309 310static __always_inline int constant_test_bit(long nr, const volatile unsigned long *addr) 311{ 312 return ((1UL << (nr & (BITS_PER_LONG-1))) & 313 (addr[nr >> _BITOPS_LONG_SHIFT])) != 0; 314} 315 316static inline int variable_test_bit(long nr, volatile const unsigned long *addr) 317{ 318 int oldbit; 319 320 asm volatile("bt %2,%1\n\t" 321 "sbb %0,%0" 322 : "=r" (oldbit) 323 : "m" (*(unsigned long *)addr), "Ir" (nr)); 324 325 return oldbit; 326} 327 328#if 0 /* Fool kernel-doc since it doesn't do macros yet */ 329/** 330 * test_bit - Determine whether a bit is set 331 * @nr: bit number to test 332 * @addr: Address to start counting from 333 */ 334static int test_bit(int nr, const volatile unsigned long *addr); 335#endif 336 337#define test_bit(nr, addr) \ 338 (__builtin_constant_p((nr)) \ 339 ? constant_test_bit((nr), (addr)) \ 340 : variable_test_bit((nr), (addr))) 341 342/** 343 * __ffs - find first set bit in word 344 * @word: The word to search 345 * 346 * Undefined if no bit exists, so code should check against 0 first. 347 */ 348static inline unsigned long __ffs(unsigned long word) 349{ 350 asm("rep; bsf %1,%0" 351 : "=r" (word) 352 : "rm" (word)); 353 return word; 354} 355 356/** 357 * ffz - find first zero bit in word 358 * @word: The word to search 359 * 360 * Undefined if no zero exists, so code should check against ~0UL first. 361 */ 362static inline unsigned long ffz(unsigned long word) 363{ 364 asm("rep; bsf %1,%0" 365 : "=r" (word) 366 : "r" (~word)); 367 return word; 368} 369 370/* 371 * __fls: find last set bit in word 372 * @word: The word to search 373 * 374 * Undefined if no set bit exists, so code should check against 0 first. 375 */ 376static inline unsigned long __fls(unsigned long word) 377{ 378 asm("bsr %1,%0" 379 : "=r" (word) 380 : "rm" (word)); 381 return word; 382} 383 384#undef ADDR 385 386#ifdef __KERNEL__ 387/** 388 * ffs - find first set bit in word 389 * @x: the word to search 390 * 391 * This is defined the same way as the libc and compiler builtin ffs 392 * routines, therefore differs in spirit from the other bitops. 393 * 394 * ffs(value) returns 0 if value is 0 or the position of the first 395 * set bit if value is nonzero. The first (least significant) bit 396 * is at position 1. 397 */ 398static inline int ffs(int x) 399{ 400 int r; 401 402#ifdef CONFIG_X86_64 403 /* 404 * AMD64 says BSFL won't clobber the dest reg if x==0; Intel64 says the 405 * dest reg is undefined if x==0, but their CPU architect says its 406 * value is written to set it to the same as before, except that the 407 * top 32 bits will be cleared. 408 * 409 * We cannot do this on 32 bits because at the very least some 410 * 486 CPUs did not behave this way. 411 */ 412 asm("bsfl %1,%0" 413 : "=r" (r) 414 : "rm" (x), "0" (-1)); 415#elif defined(CONFIG_X86_CMOV) 416 asm("bsfl %1,%0\n\t" 417 "cmovzl %2,%0" 418 : "=&r" (r) : "rm" (x), "r" (-1)); 419#else 420 asm("bsfl %1,%0\n\t" 421 "jnz 1f\n\t" 422 "movl $-1,%0\n" 423 "1:" : "=r" (r) : "rm" (x)); 424#endif 425 return r + 1; 426} 427 428/** 429 * fls - find last set bit in word 430 * @x: the word to search 431 * 432 * This is defined in a similar way as the libc and compiler builtin 433 * ffs, but returns the position of the most significant set bit. 434 * 435 * fls(value) returns 0 if value is 0 or the position of the last 436 * set bit if value is nonzero. The last (most significant) bit is 437 * at position 32. 438 */ 439static inline int fls(int x) 440{ 441 int r; 442 443#ifdef CONFIG_X86_64 444 /* 445 * AMD64 says BSRL won't clobber the dest reg if x==0; Intel64 says the 446 * dest reg is undefined if x==0, but their CPU architect says its 447 * value is written to set it to the same as before, except that the 448 * top 32 bits will be cleared. 449 * 450 * We cannot do this on 32 bits because at the very least some 451 * 486 CPUs did not behave this way. 452 */ 453 asm("bsrl %1,%0" 454 : "=r" (r) 455 : "rm" (x), "0" (-1)); 456#elif defined(CONFIG_X86_CMOV) 457 asm("bsrl %1,%0\n\t" 458 "cmovzl %2,%0" 459 : "=&r" (r) : "rm" (x), "rm" (-1)); 460#else 461 asm("bsrl %1,%0\n\t" 462 "jnz 1f\n\t" 463 "movl $-1,%0\n" 464 "1:" : "=r" (r) : "rm" (x)); 465#endif 466 return r + 1; 467} 468 469/** 470 * fls64 - find last set bit in a 64-bit word 471 * @x: the word to search 472 * 473 * This is defined in a similar way as the libc and compiler builtin 474 * ffsll, but returns the position of the most significant set bit. 475 * 476 * fls64(value) returns 0 if value is 0 or the position of the last 477 * set bit if value is nonzero. The last (most significant) bit is 478 * at position 64. 479 */ 480#ifdef CONFIG_X86_64 481static __always_inline int fls64(__u64 x) 482{ 483 int bitpos = -1; 484 /* 485 * AMD64 says BSRQ won't clobber the dest reg if x==0; Intel64 says the 486 * dest reg is undefined if x==0, but their CPU architect says its 487 * value is written to set it to the same as before. 488 */ 489 asm("bsrq %1,%q0" 490 : "+r" (bitpos) 491 : "rm" (x)); 492 return bitpos + 1; 493} 494#else 495#include <asm-generic/bitops/fls64.h> 496#endif 497 498#include <asm-generic/bitops/find.h> 499 500#include <asm-generic/bitops/sched.h> 501 502#define ARCH_HAS_FAST_MULTIPLIER 1 503 504#include <asm/arch_hweight.h> 505 506#include <asm-generic/bitops/const_hweight.h> 507 508#include <asm-generic/bitops/le.h> 509 510#include <asm-generic/bitops/ext2-atomic-setbit.h> 511 512#endif /* __KERNEL__ */ 513#endif /* _ASM_X86_BITOPS_H */ 514