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