1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_BITOPS_H 3 #define _ASM_X86_BITOPS_H 4 5 /* 6 * Copyright 1992, Linus Torvalds. 7 * 8 * Note: inlines with more than a single statement should be marked 9 * __always_inline to avoid problems with older gcc's inlining heuristics. 10 */ 11 12 #ifndef _LINUX_BITOPS_H 13 #error only <linux/bitops.h> can be included directly 14 #endif 15 16 #include <linux/compiler.h> 17 #include <asm/alternative.h> 18 #include <asm/rmwcc.h> 19 #include <asm/barrier.h> 20 21 #if BITS_PER_LONG == 32 22 # define _BITOPS_LONG_SHIFT 5 23 #elif BITS_PER_LONG == 64 24 # define _BITOPS_LONG_SHIFT 6 25 #else 26 # error "Unexpected BITS_PER_LONG" 27 #endif 28 29 #define BIT_64(n) (U64_C(1) << (n)) 30 31 /* 32 * These have to be done with inline assembly: that way the bit-setting 33 * is guaranteed to be atomic. All bit operations return 0 if the bit 34 * was cleared before the operation and != 0 if it was not. 35 * 36 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). 37 */ 38 39 #define RLONG_ADDR(x) "m" (*(volatile long *) (x)) 40 #define WBYTE_ADDR(x) "+m" (*(volatile char *) (x)) 41 42 #define ADDR RLONG_ADDR(addr) 43 44 /* 45 * We do the locked ops that don't return the old value as 46 * a mask operation on a byte. 47 */ 48 #define CONST_MASK_ADDR(nr, addr) WBYTE_ADDR((void *)(addr) + ((nr)>>3)) 49 #define CONST_MASK(nr) (1 << ((nr) & 7)) 50 51 static __always_inline void 52 arch_set_bit(long nr, volatile unsigned long *addr) 53 { 54 if (__builtin_constant_p(nr)) { 55 asm volatile(LOCK_PREFIX "orb %b1,%0" 56 : CONST_MASK_ADDR(nr, addr) 57 : "iq" (CONST_MASK(nr)) 58 : "memory"); 59 } else { 60 asm volatile(LOCK_PREFIX __ASM_SIZE(bts) " %1,%0" 61 : : RLONG_ADDR(addr), "Ir" (nr) : "memory"); 62 } 63 } 64 65 static __always_inline void 66 arch___set_bit(unsigned long nr, volatile unsigned long *addr) 67 { 68 asm volatile(__ASM_SIZE(bts) " %1,%0" : : ADDR, "Ir" (nr) : "memory"); 69 } 70 71 static __always_inline void 72 arch_clear_bit(long nr, volatile unsigned long *addr) 73 { 74 if (__builtin_constant_p(nr)) { 75 asm volatile(LOCK_PREFIX "andb %b1,%0" 76 : CONST_MASK_ADDR(nr, addr) 77 : "iq" (~CONST_MASK(nr))); 78 } else { 79 asm volatile(LOCK_PREFIX __ASM_SIZE(btr) " %1,%0" 80 : : RLONG_ADDR(addr), "Ir" (nr) : "memory"); 81 } 82 } 83 84 static __always_inline void 85 arch_clear_bit_unlock(long nr, volatile unsigned long *addr) 86 { 87 barrier(); 88 arch_clear_bit(nr, addr); 89 } 90 91 static __always_inline void 92 arch___clear_bit(unsigned long nr, volatile unsigned long *addr) 93 { 94 asm volatile(__ASM_SIZE(btr) " %1,%0" : : ADDR, "Ir" (nr) : "memory"); 95 } 96 97 static __always_inline bool arch_xor_unlock_is_negative_byte(unsigned long mask, 98 volatile unsigned long *addr) 99 { 100 bool negative; 101 asm volatile(LOCK_PREFIX "xorb %2,%1" 102 CC_SET(s) 103 : CC_OUT(s) (negative), WBYTE_ADDR(addr) 104 : "iq" ((char)mask) : "memory"); 105 return negative; 106 } 107 #define arch_xor_unlock_is_negative_byte arch_xor_unlock_is_negative_byte 108 109 static __always_inline void 110 arch___clear_bit_unlock(long nr, volatile unsigned long *addr) 111 { 112 arch___clear_bit(nr, addr); 113 } 114 115 static __always_inline void 116 arch___change_bit(unsigned long nr, volatile unsigned long *addr) 117 { 118 asm volatile(__ASM_SIZE(btc) " %1,%0" : : ADDR, "Ir" (nr) : "memory"); 119 } 120 121 static __always_inline void 122 arch_change_bit(long nr, volatile unsigned long *addr) 123 { 124 if (__builtin_constant_p(nr)) { 125 asm volatile(LOCK_PREFIX "xorb %b1,%0" 126 : CONST_MASK_ADDR(nr, addr) 127 : "iq" (CONST_MASK(nr))); 128 } else { 129 asm volatile(LOCK_PREFIX __ASM_SIZE(btc) " %1,%0" 130 : : RLONG_ADDR(addr), "Ir" (nr) : "memory"); 131 } 132 } 133 134 static __always_inline bool 135 arch_test_and_set_bit(long nr, volatile unsigned long *addr) 136 { 137 return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(bts), *addr, c, "Ir", nr); 138 } 139 140 static __always_inline bool 141 arch_test_and_set_bit_lock(long nr, volatile unsigned long *addr) 142 { 143 return arch_test_and_set_bit(nr, addr); 144 } 145 146 static __always_inline bool 147 arch___test_and_set_bit(unsigned long nr, volatile unsigned long *addr) 148 { 149 bool oldbit; 150 151 asm(__ASM_SIZE(bts) " %2,%1" 152 CC_SET(c) 153 : CC_OUT(c) (oldbit) 154 : ADDR, "Ir" (nr) : "memory"); 155 return oldbit; 156 } 157 158 static __always_inline bool 159 arch_test_and_clear_bit(long nr, volatile unsigned long *addr) 160 { 161 return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btr), *addr, c, "Ir", nr); 162 } 163 164 /* 165 * Note: the operation is performed atomically with respect to 166 * the local CPU, but not other CPUs. Portable code should not 167 * rely on this behaviour. 168 * KVM relies on this behaviour on x86 for modifying memory that is also 169 * accessed from a hypervisor on the same CPU if running in a VM: don't change 170 * this without also updating arch/x86/kernel/kvm.c 171 */ 172 static __always_inline bool 173 arch___test_and_clear_bit(unsigned long nr, volatile unsigned long *addr) 174 { 175 bool oldbit; 176 177 asm volatile(__ASM_SIZE(btr) " %2,%1" 178 CC_SET(c) 179 : CC_OUT(c) (oldbit) 180 : ADDR, "Ir" (nr) : "memory"); 181 return oldbit; 182 } 183 184 static __always_inline bool 185 arch___test_and_change_bit(unsigned long nr, volatile unsigned long *addr) 186 { 187 bool oldbit; 188 189 asm volatile(__ASM_SIZE(btc) " %2,%1" 190 CC_SET(c) 191 : CC_OUT(c) (oldbit) 192 : ADDR, "Ir" (nr) : "memory"); 193 194 return oldbit; 195 } 196 197 static __always_inline bool 198 arch_test_and_change_bit(long nr, volatile unsigned long *addr) 199 { 200 return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btc), *addr, c, "Ir", nr); 201 } 202 203 static __always_inline bool constant_test_bit(long nr, const volatile unsigned long *addr) 204 { 205 return ((1UL << (nr & (BITS_PER_LONG-1))) & 206 (addr[nr >> _BITOPS_LONG_SHIFT])) != 0; 207 } 208 209 static __always_inline bool constant_test_bit_acquire(long nr, const volatile unsigned long *addr) 210 { 211 bool oldbit; 212 213 asm volatile("testb %2,%1" 214 CC_SET(nz) 215 : CC_OUT(nz) (oldbit) 216 : "m" (((unsigned char *)addr)[nr >> 3]), 217 "i" (1 << (nr & 7)) 218 :"memory"); 219 220 return oldbit; 221 } 222 223 static __always_inline bool variable_test_bit(long nr, volatile const unsigned long *addr) 224 { 225 bool oldbit; 226 227 asm volatile(__ASM_SIZE(bt) " %2,%1" 228 CC_SET(c) 229 : CC_OUT(c) (oldbit) 230 : "m" (*(unsigned long *)addr), "Ir" (nr) : "memory"); 231 232 return oldbit; 233 } 234 235 static __always_inline bool 236 arch_test_bit(unsigned long nr, const volatile unsigned long *addr) 237 { 238 return __builtin_constant_p(nr) ? constant_test_bit(nr, addr) : 239 variable_test_bit(nr, addr); 240 } 241 242 static __always_inline bool 243 arch_test_bit_acquire(unsigned long nr, const volatile unsigned long *addr) 244 { 245 return __builtin_constant_p(nr) ? constant_test_bit_acquire(nr, addr) : 246 variable_test_bit(nr, addr); 247 } 248 249 static __always_inline unsigned long variable__ffs(unsigned long word) 250 { 251 asm("rep; bsf %1,%0" 252 : "=r" (word) 253 : ASM_INPUT_RM (word)); 254 return word; 255 } 256 257 /** 258 * __ffs - find first set bit in word 259 * @word: The word to search 260 * 261 * Undefined if no bit exists, so code should check against 0 first. 262 */ 263 #define __ffs(word) \ 264 (__builtin_constant_p(word) ? \ 265 (unsigned long)__builtin_ctzl(word) : \ 266 variable__ffs(word)) 267 268 static __always_inline unsigned long variable_ffz(unsigned long word) 269 { 270 asm("rep; bsf %1,%0" 271 : "=r" (word) 272 : "r" (~word)); 273 return word; 274 } 275 276 /** 277 * ffz - find first zero bit in word 278 * @word: The word to search 279 * 280 * Undefined if no zero exists, so code should check against ~0UL first. 281 */ 282 #define ffz(word) \ 283 (__builtin_constant_p(word) ? \ 284 (unsigned long)__builtin_ctzl(~word) : \ 285 variable_ffz(word)) 286 287 /* 288 * __fls: find last set bit in word 289 * @word: The word to search 290 * 291 * Undefined if no set bit exists, so code should check against 0 first. 292 */ 293 static __always_inline unsigned long __fls(unsigned long word) 294 { 295 if (__builtin_constant_p(word)) 296 return BITS_PER_LONG - 1 - __builtin_clzl(word); 297 298 asm("bsr %1,%0" 299 : "=r" (word) 300 : ASM_INPUT_RM (word)); 301 return word; 302 } 303 304 #undef ADDR 305 306 #ifdef __KERNEL__ 307 static __always_inline int variable_ffs(int x) 308 { 309 int r; 310 311 #ifdef CONFIG_X86_64 312 /* 313 * AMD64 says BSFL won't clobber the dest reg if x==0; Intel64 says the 314 * dest reg is undefined if x==0, but their CPU architect says its 315 * value is written to set it to the same as before, except that the 316 * top 32 bits will be cleared. 317 * 318 * We cannot do this on 32 bits because at the very least some 319 * 486 CPUs did not behave this way. 320 */ 321 asm("bsfl %1,%0" 322 : "=r" (r) 323 : ASM_INPUT_RM (x), "0" (-1)); 324 #elif defined(CONFIG_X86_CMOV) 325 asm("bsfl %1,%0\n\t" 326 "cmovzl %2,%0" 327 : "=&r" (r) : "rm" (x), "r" (-1)); 328 #else 329 asm("bsfl %1,%0\n\t" 330 "jnz 1f\n\t" 331 "movl $-1,%0\n" 332 "1:" : "=r" (r) : "rm" (x)); 333 #endif 334 return r + 1; 335 } 336 337 /** 338 * ffs - find first set bit in word 339 * @x: the word to search 340 * 341 * This is defined the same way as the libc and compiler builtin ffs 342 * routines, therefore differs in spirit from the other bitops. 343 * 344 * ffs(value) returns 0 if value is 0 or the position of the first 345 * set bit if value is nonzero. The first (least significant) bit 346 * is at position 1. 347 */ 348 #define ffs(x) (__builtin_constant_p(x) ? __builtin_ffs(x) : variable_ffs(x)) 349 350 /** 351 * fls - find last set bit in word 352 * @x: the word to search 353 * 354 * This is defined in a similar way as the libc and compiler builtin 355 * ffs, but returns the position of the most significant set bit. 356 * 357 * fls(value) returns 0 if value is 0 or the position of the last 358 * set bit if value is nonzero. The last (most significant) bit is 359 * at position 32. 360 */ 361 static __always_inline int fls(unsigned int x) 362 { 363 int r; 364 365 if (__builtin_constant_p(x)) 366 return x ? 32 - __builtin_clz(x) : 0; 367 368 #ifdef CONFIG_X86_64 369 /* 370 * AMD64 says BSRL won't clobber the dest reg if x==0; Intel64 says the 371 * dest reg is undefined if x==0, but their CPU architect says its 372 * value is written to set it to the same as before, except that the 373 * top 32 bits will be cleared. 374 * 375 * We cannot do this on 32 bits because at the very least some 376 * 486 CPUs did not behave this way. 377 */ 378 asm("bsrl %1,%0" 379 : "=r" (r) 380 : ASM_INPUT_RM (x), "0" (-1)); 381 #elif defined(CONFIG_X86_CMOV) 382 asm("bsrl %1,%0\n\t" 383 "cmovzl %2,%0" 384 : "=&r" (r) : "rm" (x), "rm" (-1)); 385 #else 386 asm("bsrl %1,%0\n\t" 387 "jnz 1f\n\t" 388 "movl $-1,%0\n" 389 "1:" : "=r" (r) : "rm" (x)); 390 #endif 391 return r + 1; 392 } 393 394 /** 395 * fls64 - find last set bit in a 64-bit word 396 * @x: the word to search 397 * 398 * This is defined in a similar way as the libc and compiler builtin 399 * ffsll, but returns the position of the most significant set bit. 400 * 401 * fls64(value) returns 0 if value is 0 or the position of the last 402 * set bit if value is nonzero. The last (most significant) bit is 403 * at position 64. 404 */ 405 #ifdef CONFIG_X86_64 406 static __always_inline int fls64(__u64 x) 407 { 408 int bitpos = -1; 409 410 if (__builtin_constant_p(x)) 411 return x ? 64 - __builtin_clzll(x) : 0; 412 /* 413 * AMD64 says BSRQ won't clobber the dest reg if x==0; Intel64 says the 414 * dest reg is undefined if x==0, but their CPU architect says its 415 * value is written to set it to the same as before. 416 */ 417 asm("bsrq %1,%q0" 418 : "+r" (bitpos) 419 : ASM_INPUT_RM (x)); 420 return bitpos + 1; 421 } 422 #else 423 #include <asm-generic/bitops/fls64.h> 424 #endif 425 426 #include <asm-generic/bitops/sched.h> 427 428 #include <asm/arch_hweight.h> 429 430 #include <asm-generic/bitops/const_hweight.h> 431 432 #include <asm-generic/bitops/instrumented-atomic.h> 433 #include <asm-generic/bitops/instrumented-non-atomic.h> 434 #include <asm-generic/bitops/instrumented-lock.h> 435 436 #include <asm-generic/bitops/le.h> 437 438 #include <asm-generic/bitops/ext2-atomic-setbit.h> 439 440 #endif /* __KERNEL__ */ 441 #endif /* _ASM_X86_BITOPS_H */ 442