1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_BITOPS_H 3 #define _LINUX_BITOPS_H 4 5 #include <asm/types.h> 6 #include <linux/bits.h> 7 #include <linux/typecheck.h> 8 9 #include <uapi/linux/kernel.h> 10 11 /* Set bits in the first 'n' bytes when loaded from memory */ 12 #ifdef __LITTLE_ENDIAN 13 # define aligned_byte_mask(n) ((1UL << 8*(n))-1) 14 #else 15 # define aligned_byte_mask(n) (~0xffUL << (BITS_PER_LONG - 8 - 8*(n))) 16 #endif 17 18 #define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE) 19 #define BITS_TO_LONGS(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(long)) 20 #define BITS_TO_U64(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u64)) 21 #define BITS_TO_U32(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u32)) 22 #define BITS_TO_BYTES(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(char)) 23 24 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_BYTE) 25 26 extern unsigned int __sw_hweight8(unsigned int w); 27 extern unsigned int __sw_hweight16(unsigned int w); 28 extern unsigned int __sw_hweight32(unsigned int w); 29 extern unsigned long __sw_hweight64(__u64 w); 30 31 /* 32 * Defined here because those may be needed by architecture-specific static 33 * inlines. 34 */ 35 36 #include <asm-generic/bitops/generic-non-atomic.h> 37 38 /* 39 * Many architecture-specific non-atomic bitops contain inline asm code and due 40 * to that the compiler can't optimize them to compile-time expressions or 41 * constants. In contrary, generic_*() helpers are defined in pure C and 42 * compilers optimize them just well. 43 * Therefore, to make `unsigned long foo = 0; __set_bit(BAR, &foo)` effectively 44 * equal to `unsigned long foo = BIT(BAR)`, pick the generic C alternative when 45 * the arguments can be resolved at compile time. That expression itself is a 46 * constant and doesn't bring any functional changes to the rest of cases. 47 * The casts to `uintptr_t` are needed to mitigate `-Waddress` warnings when 48 * passing a bitmap from .bss or .data (-> `!!addr` is always true). 49 */ 50 #define bitop(op, nr, addr) \ 51 ((__builtin_constant_p(nr) && \ 52 __builtin_constant_p((uintptr_t)(addr) != (uintptr_t)NULL) && \ 53 (uintptr_t)(addr) != (uintptr_t)NULL && \ 54 __builtin_constant_p(*(const unsigned long *)(addr))) ? \ 55 const##op(nr, addr) : op(nr, addr)) 56 57 #define __set_bit(nr, addr) bitop(___set_bit, nr, addr) 58 #define __clear_bit(nr, addr) bitop(___clear_bit, nr, addr) 59 #define __change_bit(nr, addr) bitop(___change_bit, nr, addr) 60 #define __test_and_set_bit(nr, addr) bitop(___test_and_set_bit, nr, addr) 61 #define __test_and_clear_bit(nr, addr) bitop(___test_and_clear_bit, nr, addr) 62 #define __test_and_change_bit(nr, addr) bitop(___test_and_change_bit, nr, addr) 63 #define test_bit(nr, addr) bitop(_test_bit, nr, addr) 64 #define test_bit_acquire(nr, addr) bitop(_test_bit_acquire, nr, addr) 65 66 /* 67 * Include this here because some architectures need generic_ffs/fls in 68 * scope 69 */ 70 #include <asm/bitops.h> 71 72 /* Check that the bitops prototypes are sane */ 73 #define __check_bitop_pr(name) \ 74 static_assert(__same_type(arch_##name, generic_##name) && \ 75 __same_type(const_##name, generic_##name) && \ 76 __same_type(_##name, generic_##name)) 77 78 __check_bitop_pr(__set_bit); 79 __check_bitop_pr(__clear_bit); 80 __check_bitop_pr(__change_bit); 81 __check_bitop_pr(__test_and_set_bit); 82 __check_bitop_pr(__test_and_clear_bit); 83 __check_bitop_pr(__test_and_change_bit); 84 __check_bitop_pr(test_bit); 85 __check_bitop_pr(test_bit_acquire); 86 87 #undef __check_bitop_pr 88 89 static inline int get_bitmask_order(unsigned int count) 90 { 91 int order; 92 93 order = fls(count); 94 return order; /* We could be slightly more clever with -1 here... */ 95 } 96 97 static __always_inline unsigned long hweight_long(unsigned long w) 98 { 99 return sizeof(w) == 4 ? hweight32(w) : hweight64((__u64)w); 100 } 101 102 /** 103 * rol64 - rotate a 64-bit value left 104 * @word: value to rotate 105 * @shift: bits to roll 106 */ 107 static inline __u64 rol64(__u64 word, unsigned int shift) 108 { 109 return (word << (shift & 63)) | (word >> ((-shift) & 63)); 110 } 111 112 /** 113 * ror64 - rotate a 64-bit value right 114 * @word: value to rotate 115 * @shift: bits to roll 116 */ 117 static inline __u64 ror64(__u64 word, unsigned int shift) 118 { 119 return (word >> (shift & 63)) | (word << ((-shift) & 63)); 120 } 121 122 /** 123 * rol32 - rotate a 32-bit value left 124 * @word: value to rotate 125 * @shift: bits to roll 126 */ 127 static inline __u32 rol32(__u32 word, unsigned int shift) 128 { 129 return (word << (shift & 31)) | (word >> ((-shift) & 31)); 130 } 131 132 /** 133 * ror32 - rotate a 32-bit value right 134 * @word: value to rotate 135 * @shift: bits to roll 136 */ 137 static inline __u32 ror32(__u32 word, unsigned int shift) 138 { 139 return (word >> (shift & 31)) | (word << ((-shift) & 31)); 140 } 141 142 /** 143 * rol16 - rotate a 16-bit value left 144 * @word: value to rotate 145 * @shift: bits to roll 146 */ 147 static inline __u16 rol16(__u16 word, unsigned int shift) 148 { 149 return (word << (shift & 15)) | (word >> ((-shift) & 15)); 150 } 151 152 /** 153 * ror16 - rotate a 16-bit value right 154 * @word: value to rotate 155 * @shift: bits to roll 156 */ 157 static inline __u16 ror16(__u16 word, unsigned int shift) 158 { 159 return (word >> (shift & 15)) | (word << ((-shift) & 15)); 160 } 161 162 /** 163 * rol8 - rotate an 8-bit value left 164 * @word: value to rotate 165 * @shift: bits to roll 166 */ 167 static inline __u8 rol8(__u8 word, unsigned int shift) 168 { 169 return (word << (shift & 7)) | (word >> ((-shift) & 7)); 170 } 171 172 /** 173 * ror8 - rotate an 8-bit value right 174 * @word: value to rotate 175 * @shift: bits to roll 176 */ 177 static inline __u8 ror8(__u8 word, unsigned int shift) 178 { 179 return (word >> (shift & 7)) | (word << ((-shift) & 7)); 180 } 181 182 /** 183 * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit 184 * @value: value to sign extend 185 * @index: 0 based bit index (0<=index<32) to sign bit 186 * 187 * This is safe to use for 16- and 8-bit types as well. 188 */ 189 static __always_inline __s32 sign_extend32(__u32 value, int index) 190 { 191 __u8 shift = 31 - index; 192 return (__s32)(value << shift) >> shift; 193 } 194 195 /** 196 * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit 197 * @value: value to sign extend 198 * @index: 0 based bit index (0<=index<64) to sign bit 199 */ 200 static __always_inline __s64 sign_extend64(__u64 value, int index) 201 { 202 __u8 shift = 63 - index; 203 return (__s64)(value << shift) >> shift; 204 } 205 206 static inline unsigned fls_long(unsigned long l) 207 { 208 if (sizeof(l) == 4) 209 return fls(l); 210 return fls64(l); 211 } 212 213 static inline int get_count_order(unsigned int count) 214 { 215 if (count == 0) 216 return -1; 217 218 return fls(--count); 219 } 220 221 /** 222 * get_count_order_long - get order after rounding @l up to power of 2 223 * @l: parameter 224 * 225 * it is same as get_count_order() but with long type parameter 226 */ 227 static inline int get_count_order_long(unsigned long l) 228 { 229 if (l == 0UL) 230 return -1; 231 return (int)fls_long(--l); 232 } 233 234 /** 235 * __ffs64 - find first set bit in a 64 bit word 236 * @word: The 64 bit word 237 * 238 * On 64 bit arches this is a synonym for __ffs 239 * The result is not defined if no bits are set, so check that @word 240 * is non-zero before calling this. 241 */ 242 static inline unsigned long __ffs64(u64 word) 243 { 244 #if BITS_PER_LONG == 32 245 if (((u32)word) == 0UL) 246 return __ffs((u32)(word >> 32)) + 32; 247 #elif BITS_PER_LONG != 64 248 #error BITS_PER_LONG not 32 or 64 249 #endif 250 return __ffs((unsigned long)word); 251 } 252 253 /** 254 * fns - find N'th set bit in a word 255 * @word: The word to search 256 * @n: Bit to find 257 */ 258 static inline unsigned long fns(unsigned long word, unsigned int n) 259 { 260 unsigned int bit; 261 262 while (word) { 263 bit = __ffs(word); 264 if (n-- == 0) 265 return bit; 266 __clear_bit(bit, &word); 267 } 268 269 return BITS_PER_LONG; 270 } 271 272 /** 273 * assign_bit - Assign value to a bit in memory 274 * @nr: the bit to set 275 * @addr: the address to start counting from 276 * @value: the value to assign 277 */ 278 static __always_inline void assign_bit(long nr, volatile unsigned long *addr, 279 bool value) 280 { 281 if (value) 282 set_bit(nr, addr); 283 else 284 clear_bit(nr, addr); 285 } 286 287 static __always_inline void __assign_bit(long nr, volatile unsigned long *addr, 288 bool value) 289 { 290 if (value) 291 __set_bit(nr, addr); 292 else 293 __clear_bit(nr, addr); 294 } 295 296 /** 297 * __ptr_set_bit - Set bit in a pointer's value 298 * @nr: the bit to set 299 * @addr: the address of the pointer variable 300 * 301 * Example: 302 * void *p = foo(); 303 * __ptr_set_bit(bit, &p); 304 */ 305 #define __ptr_set_bit(nr, addr) \ 306 ({ \ 307 typecheck_pointer(*(addr)); \ 308 __set_bit(nr, (unsigned long *)(addr)); \ 309 }) 310 311 /** 312 * __ptr_clear_bit - Clear bit in a pointer's value 313 * @nr: the bit to clear 314 * @addr: the address of the pointer variable 315 * 316 * Example: 317 * void *p = foo(); 318 * __ptr_clear_bit(bit, &p); 319 */ 320 #define __ptr_clear_bit(nr, addr) \ 321 ({ \ 322 typecheck_pointer(*(addr)); \ 323 __clear_bit(nr, (unsigned long *)(addr)); \ 324 }) 325 326 /** 327 * __ptr_test_bit - Test bit in a pointer's value 328 * @nr: the bit to test 329 * @addr: the address of the pointer variable 330 * 331 * Example: 332 * void *p = foo(); 333 * if (__ptr_test_bit(bit, &p)) { 334 * ... 335 * } else { 336 * ... 337 * } 338 */ 339 #define __ptr_test_bit(nr, addr) \ 340 ({ \ 341 typecheck_pointer(*(addr)); \ 342 test_bit(nr, (unsigned long *)(addr)); \ 343 }) 344 345 #ifdef __KERNEL__ 346 347 #ifndef set_mask_bits 348 #define set_mask_bits(ptr, mask, bits) \ 349 ({ \ 350 const typeof(*(ptr)) mask__ = (mask), bits__ = (bits); \ 351 typeof(*(ptr)) old__, new__; \ 352 \ 353 old__ = READ_ONCE(*(ptr)); \ 354 do { \ 355 new__ = (old__ & ~mask__) | bits__; \ 356 } while (!try_cmpxchg(ptr, &old__, new__)); \ 357 \ 358 old__; \ 359 }) 360 #endif 361 362 #ifndef bit_clear_unless 363 #define bit_clear_unless(ptr, clear, test) \ 364 ({ \ 365 const typeof(*(ptr)) clear__ = (clear), test__ = (test);\ 366 typeof(*(ptr)) old__, new__; \ 367 \ 368 old__ = READ_ONCE(*(ptr)); \ 369 do { \ 370 if (old__ & test__) \ 371 break; \ 372 new__ = old__ & ~clear__; \ 373 } while (!try_cmpxchg(ptr, &old__, new__)); \ 374 \ 375 !(old__ & test__); \ 376 }) 377 #endif 378 379 #endif /* __KERNEL__ */ 380 #endif 381