include/linux/bitops.h

   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
   8 #include <uapi/linux/kernel.h>
   9
  10 /* Set bits in the first 'n' bytes when loaded from memory */
  11 #ifdef __LITTLE_ENDIAN
  12 #  define aligned_byte_mask(n) ((1UL << 8*(n))-1)
  13 #else
  14 #  define aligned_byte_mask(n) (~0xffUL << (BITS_PER_LONG - 8 - 8*(n)))
  15 #endif
  16
  17 #define BITS_PER_TYPE(type)     (sizeof(type) * BITS_PER_BYTE)
  18 #define BITS_TO_LONGS(nr)       __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(long))
  19 #define BITS_TO_U64(nr)         __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u64))
  20 #define BITS_TO_U32(nr)         __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u32))
  21 #define BITS_TO_BYTES(nr)       __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(char))
  22
  23 extern unsigned int __sw_hweight8(unsigned int w);
  24 extern unsigned int __sw_hweight16(unsigned int w);
  25 extern unsigned int __sw_hweight32(unsigned int w);
  26 extern unsigned long __sw_hweight64(__u64 w);
  27
  28 /*
  29  * Include this here because some architectures need generic_ffs/fls in
  30  * scope
  31  */
  32 #include <asm/bitops.h>
  33
  34 #define for_each_set_bit(bit, addr, size) \
  35         for ((bit) = find_first_bit((addr), (size));            \
  36              (bit) < (size);                                    \
  37              (bit) = find_next_bit((addr), (size), (bit) + 1))
  38
  39 /* same as for_each_set_bit() but use bit as value to start with */
  40 #define for_each_set_bit_from(bit, addr, size) \
  41         for ((bit) = find_next_bit((addr), (size), (bit));      \
  42              (bit) < (size);                                    \
  43              (bit) = find_next_bit((addr), (size), (bit) + 1))
  44
  45 #define for_each_clear_bit(bit, addr, size) \
  46         for ((bit) = find_first_zero_bit((addr), (size));       \
  47              (bit) < (size);                                    \
  48              (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  49
  50 /* same as for_each_clear_bit() but use bit as value to start with */
  51 #define for_each_clear_bit_from(bit, addr, size) \
  52         for ((bit) = find_next_zero_bit((addr), (size), (bit)); \
  53              (bit) < (size);                                    \
  54              (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  55
  56 /**
  57  * for_each_set_clump8 - iterate over bitmap for each 8-bit clump with set bits
  58  * @start: bit offset to start search and to store the current iteration offset
  59  * @clump: location to store copy of current 8-bit clump
  60  * @bits: bitmap address to base the search on
  61  * @size: bitmap size in number of bits
  62  */
  63 #define for_each_set_clump8(start, clump, bits, size) \
  64         for ((start) = find_first_clump8(&(clump), (bits), (size)); \
  65              (start) < (size); \
  66              (start) = find_next_clump8(&(clump), (bits), (size), (start) + 8))
  67
  68 static inline int get_bitmask_order(unsigned int count)
  69 {
  70         int order;
  71
  72         order = fls(count);
  73         return order;   /* We could be slightly more clever with -1 here... */
  74 }
  75
  76 static __always_inline unsigned long hweight_long(unsigned long w)
  77 {
  78         return sizeof(w) == 4 ? hweight32(w) : hweight64((__u64)w);
  79 }
  80
  81 /**
  82  * rol64 - rotate a 64-bit value left
  83  * @word: value to rotate
  84  * @shift: bits to roll
  85  */
  86 static inline __u64 rol64(__u64 word, unsigned int shift)
  87 {
  88         return (word << (shift & 63)) | (word >> ((-shift) & 63));
  89 }
  90
  91 /**
  92  * ror64 - rotate a 64-bit value right
  93  * @word: value to rotate
  94  * @shift: bits to roll
  95  */
  96 static inline __u64 ror64(__u64 word, unsigned int shift)
  97 {
  98         return (word >> (shift & 63)) | (word << ((-shift) & 63));
  99 }
 100
 101 /**
 102  * rol32 - rotate a 32-bit value left
 103  * @word: value to rotate
 104  * @shift: bits to roll
 105  */
 106 static inline __u32 rol32(__u32 word, unsigned int shift)
 107 {
 108         return (word << (shift & 31)) | (word >> ((-shift) & 31));
 109 }
 110
 111 /**
 112  * ror32 - rotate a 32-bit value right
 113  * @word: value to rotate
 114  * @shift: bits to roll
 115  */
 116 static inline __u32 ror32(__u32 word, unsigned int shift)
 117 {
 118         return (word >> (shift & 31)) | (word << ((-shift) & 31));
 119 }
 120
 121 /**
 122  * rol16 - rotate a 16-bit value left
 123  * @word: value to rotate
 124  * @shift: bits to roll
 125  */
 126 static inline __u16 rol16(__u16 word, unsigned int shift)
 127 {
 128         return (word << (shift & 15)) | (word >> ((-shift) & 15));
 129 }
 130
 131 /**
 132  * ror16 - rotate a 16-bit value right
 133  * @word: value to rotate
 134  * @shift: bits to roll
 135  */
 136 static inline __u16 ror16(__u16 word, unsigned int shift)
 137 {
 138         return (word >> (shift & 15)) | (word << ((-shift) & 15));
 139 }
 140
 141 /**
 142  * rol8 - rotate an 8-bit value left
 143  * @word: value to rotate
 144  * @shift: bits to roll
 145  */
 146 static inline __u8 rol8(__u8 word, unsigned int shift)
 147 {
 148         return (word << (shift & 7)) | (word >> ((-shift) & 7));
 149 }
 150
 151 /**
 152  * ror8 - rotate an 8-bit value right
 153  * @word: value to rotate
 154  * @shift: bits to roll
 155  */
 156 static inline __u8 ror8(__u8 word, unsigned int shift)
 157 {
 158         return (word >> (shift & 7)) | (word << ((-shift) & 7));
 159 }
 160
 161 /**
 162  * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
 163  * @value: value to sign extend
 164  * @index: 0 based bit index (0<=index<32) to sign bit
 165  *
 166  * This is safe to use for 16- and 8-bit types as well.
 167  */
 168 static __always_inline __s32 sign_extend32(__u32 value, int index)
 169 {
 170         __u8 shift = 31 - index;
 171         return (__s32)(value << shift) >> shift;
 172 }
 173
 174 /**
 175  * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit
 176  * @value: value to sign extend
 177  * @index: 0 based bit index (0<=index<64) to sign bit
 178  */
 179 static __always_inline __s64 sign_extend64(__u64 value, int index)
 180 {
 181         __u8 shift = 63 - index;
 182         return (__s64)(value << shift) >> shift;
 183 }
 184
 185 static inline unsigned fls_long(unsigned long l)
 186 {
 187         if (sizeof(l) == 4)
 188                 return fls(l);
 189         return fls64(l);
 190 }
 191
 192 static inline int get_count_order(unsigned int count)
 193 {
 194         if (count == 0)
 195                 return -1;
 196
 197         return fls(--count);
 198 }
 199
 200 /**
 201  * get_count_order_long - get order after rounding @l up to power of 2
 202  * @l: parameter
 203  *
 204  * it is same as get_count_order() but with long type parameter
 205  */
 206 static inline int get_count_order_long(unsigned long l)
 207 {
 208         if (l == 0UL)
 209                 return -1;
 210         return (int)fls_long(--l);
 211 }
 212
 213 /**
 214  * __ffs64 - find first set bit in a 64 bit word
 215  * @word: The 64 bit word
 216  *
 217  * On 64 bit arches this is a synonym for __ffs
 218  * The result is not defined if no bits are set, so check that @word
 219  * is non-zero before calling this.
 220  */
 221 static inline unsigned long __ffs64(u64 word)
 222 {
 223 #if BITS_PER_LONG == 32
 224         if (((u32)word) == 0UL)
 225                 return __ffs((u32)(word >> 32)) + 32;
 226 #elif BITS_PER_LONG != 64
 227 #error BITS_PER_LONG not 32 or 64
 228 #endif
 229         return __ffs((unsigned long)word);
 230 }
 231
 232 /**
 233  * assign_bit - Assign value to a bit in memory
 234  * @nr: the bit to set
 235  * @addr: the address to start counting from
 236  * @value: the value to assign
 237  */
 238 static __always_inline void assign_bit(long nr, volatile unsigned long *addr,
 239                                        bool value)
 240 {
 241         if (value)
 242                 set_bit(nr, addr);
 243         else
 244                 clear_bit(nr, addr);
 245 }
 246
 247 static __always_inline void __assign_bit(long nr, volatile unsigned long *addr,
 248                                          bool value)
 249 {
 250         if (value)
 251                 __set_bit(nr, addr);
 252         else
 253                 __clear_bit(nr, addr);
 254 }
 255
 256 #ifdef __KERNEL__
 257
 258 #ifndef set_mask_bits
 259 #define set_mask_bits(ptr, mask, bits)  \
 260 ({                                                              \
 261         const typeof(*(ptr)) mask__ = (mask), bits__ = (bits);  \
 262         typeof(*(ptr)) old__, new__;                            \
 263                                                                 \
 264         do {                                                    \
 265                 old__ = READ_ONCE(*(ptr));                      \
 266                 new__ = (old__ & ~mask__) | bits__;             \
 267         } while (cmpxchg(ptr, old__, new__) != old__);          \
 268                                                                 \
 269         old__;                                                  \
 270 })
 271 #endif
 272
 273 #ifndef bit_clear_unless
 274 #define bit_clear_unless(ptr, clear, test)      \
 275 ({                                                              \
 276         const typeof(*(ptr)) clear__ = (clear), test__ = (test);\
 277         typeof(*(ptr)) old__, new__;                            \
 278                                                                 \
 279         do {                                                    \
 280                 old__ = READ_ONCE(*(ptr));                      \
 281                 new__ = old__ & ~clear__;                       \
 282         } while (!(old__ & test__) &&                           \
 283                  cmpxchg(ptr, old__, new__) != old__);          \
 284                                                                 \
 285         !(old__ & test__);                                      \
 286 })
 287 #endif
 288
 289 #endif /* __KERNEL__ */
 290 #endif