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