include/linux/bitops.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_BITOPS_H
   3 #define _LINUX_BITOPS_H
   4 #include <asm/types.h>
   5
   6 #ifdef  __KERNEL__
   7 #define BIT(nr)                 (1UL << (nr))
   8 #define BIT_ULL(nr)             (1ULL << (nr))
   9 #define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
  10 #define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
  11 #define BIT_ULL_MASK(nr)        (1ULL << ((nr) % BITS_PER_LONG_LONG))
  12 #define BIT_ULL_WORD(nr)        ((nr) / BITS_PER_LONG_LONG)
  13 #define BITS_PER_BYTE           8
  14 #define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  15 #endif
  16
  17 /*
  18  * Create a contiguous bitmask starting at bit position @l and ending at
  19  * position @h. For example
  20  * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  21  */
  22 #define GENMASK(h, l) \
  23         (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
  24
  25 #define GENMASK_ULL(h, l) \
  26         (((~0ULL) - (1ULL << (l)) + 1) & \
  27          (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
  28
  29 extern unsigned int __sw_hweight8(unsigned int w);
  30 extern unsigned int __sw_hweight16(unsigned int w);
  31 extern unsigned int __sw_hweight32(unsigned int w);
  32 extern unsigned long __sw_hweight64(__u64 w);
  33
  34 /*
  35  * Include this here because some architectures need generic_ffs/fls in
  36  * scope
  37  */
  38 #include <asm/bitops.h>
  39
  40 #define for_each_set_bit(bit, addr, size) \
  41         for ((bit) = find_first_bit((addr), (size));            \
  42              (bit) < (size);                                    \
  43              (bit) = find_next_bit((addr), (size), (bit) + 1))
  44
  45 /* same as for_each_set_bit() but use bit as value to start with */
  46 #define for_each_set_bit_from(bit, addr, size) \
  47         for ((bit) = find_next_bit((addr), (size), (bit));      \
  48              (bit) < (size);                                    \
  49              (bit) = find_next_bit((addr), (size), (bit) + 1))
  50
  51 #define for_each_clear_bit(bit, addr, size) \
  52         for ((bit) = find_first_zero_bit((addr), (size));       \
  53              (bit) < (size);                                    \
  54              (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  55
  56 /* same as for_each_clear_bit() but use bit as value to start with */
  57 #define for_each_clear_bit_from(bit, addr, size) \
  58         for ((bit) = find_next_zero_bit((addr), (size), (bit)); \
  59              (bit) < (size);                                    \
  60              (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  61
  62 static inline int get_bitmask_order(unsigned int count)
  63 {
  64         int order;
  65
  66         order = fls(count);
  67         return order;   /* We could be slightly more clever with -1 here... */
  68 }
  69
  70 static __always_inline unsigned long hweight_long(unsigned long w)
  71 {
  72         return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
  73 }
  74
  75 /**
  76  * rol64 - rotate a 64-bit value left
  77  * @word: value to rotate
  78  * @shift: bits to roll
  79  */
  80 static inline __u64 rol64(__u64 word, unsigned int shift)
  81 {
  82         return (word << shift) | (word >> (64 - shift));
  83 }
  84
  85 /**
  86  * ror64 - rotate a 64-bit value right
  87  * @word: value to rotate
  88  * @shift: bits to roll
  89  */
  90 static inline __u64 ror64(__u64 word, unsigned int shift)
  91 {
  92         return (word >> shift) | (word << (64 - shift));
  93 }
  94
  95 /**
  96  * rol32 - rotate a 32-bit value left
  97  * @word: value to rotate
  98  * @shift: bits to roll
  99  */
 100 static inline __u32 rol32(__u32 word, unsigned int shift)
 101 {
 102         return (word << shift) | (word >> ((-shift) & 31));
 103 }
 104
 105 /**
 106  * ror32 - rotate a 32-bit value right
 107  * @word: value to rotate
 108  * @shift: bits to roll
 109  */
 110 static inline __u32 ror32(__u32 word, unsigned int shift)
 111 {
 112         return (word >> shift) | (word << (32 - shift));
 113 }
 114
 115 /**
 116  * rol16 - rotate a 16-bit value left
 117  * @word: value to rotate
 118  * @shift: bits to roll
 119  */
 120 static inline __u16 rol16(__u16 word, unsigned int shift)
 121 {
 122         return (word << shift) | (word >> (16 - shift));
 123 }
 124
 125 /**
 126  * ror16 - rotate a 16-bit value right
 127  * @word: value to rotate
 128  * @shift: bits to roll
 129  */
 130 static inline __u16 ror16(__u16 word, unsigned int shift)
 131 {
 132         return (word >> shift) | (word << (16 - shift));
 133 }
 134
 135 /**
 136  * rol8 - rotate an 8-bit value left
 137  * @word: value to rotate
 138  * @shift: bits to roll
 139  */
 140 static inline __u8 rol8(__u8 word, unsigned int shift)
 141 {
 142         return (word << shift) | (word >> (8 - shift));
 143 }
 144
 145 /**
 146  * ror8 - rotate an 8-bit value right
 147  * @word: value to rotate
 148  * @shift: bits to roll
 149  */
 150 static inline __u8 ror8(__u8 word, unsigned int shift)
 151 {
 152         return (word >> shift) | (word << (8 - shift));
 153 }
 154
 155 /**
 156  * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
 157  * @value: value to sign extend
 158  * @index: 0 based bit index (0<=index<32) to sign bit
 159  *
 160  * This is safe to use for 16- and 8-bit types as well.
 161  */
 162 static inline __s32 sign_extend32(__u32 value, int index)
 163 {
 164         __u8 shift = 31 - index;
 165         return (__s32)(value << shift) >> shift;
 166 }
 167
 168 /**
 169  * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit
 170  * @value: value to sign extend
 171  * @index: 0 based bit index (0<=index<64) to sign bit
 172  */
 173 static inline __s64 sign_extend64(__u64 value, int index)
 174 {
 175         __u8 shift = 63 - index;
 176         return (__s64)(value << shift) >> shift;
 177 }
 178
 179 static inline unsigned fls_long(unsigned long l)
 180 {
 181         if (sizeof(l) == 4)
 182                 return fls(l);
 183         return fls64(l);
 184 }
 185
 186 static inline int get_count_order(unsigned int count)
 187 {
 188         int order;
 189
 190         order = fls(count) - 1;
 191         if (count & (count - 1))
 192                 order++;
 193         return order;
 194 }
 195
 196 /**
 197  * get_count_order_long - get order after rounding @l up to power of 2
 198  * @l: parameter
 199  *
 200  * it is same as get_count_order() but with long type parameter
 201  */
 202 static inline int get_count_order_long(unsigned long l)
 203 {
 204         if (l == 0UL)
 205                 return -1;
 206         else if (l & (l - 1UL))
 207                 return (int)fls_long(l);
 208         else
 209                 return (int)fls_long(l) - 1;
 210 }
 211
 212 /**
 213  * __ffs64 - find first set bit in a 64 bit word
 214  * @word: The 64 bit word
 215  *
 216  * On 64 bit arches this is a synomyn for __ffs
 217  * The result is not defined if no bits are set, so check that @word
 218  * is non-zero before calling this.
 219  */
 220 static inline unsigned long __ffs64(u64 word)
 221 {
 222 #if BITS_PER_LONG == 32
 223         if (((u32)word) == 0UL)
 224                 return __ffs((u32)(word >> 32)) + 32;
 225 #elif BITS_PER_LONG != 64
 226 #error BITS_PER_LONG not 32 or 64
 227 #endif
 228         return __ffs((unsigned long)word);
 229 }
 230
 231 /**
 232  * assign_bit - Assign value to a bit in memory
 233  * @nr: the bit to set
 234  * @addr: the address to start counting from
 235  * @value: the value to assign
 236  */
 237 static __always_inline void assign_bit(long nr, volatile unsigned long *addr,
 238                                        bool value)
 239 {
 240         if (value)
 241                 set_bit(nr, addr);
 242         else
 243                 clear_bit(nr, addr);
 244 }
 245
 246 static __always_inline void __assign_bit(long nr, volatile unsigned long *addr,
 247                                          bool value)
 248 {
 249         if (value)
 250                 __set_bit(nr, addr);
 251         else
 252                 __clear_bit(nr, addr);
 253 }
 254
 255 #ifdef __KERNEL__
 256
 257 #ifndef set_mask_bits
 258 #define set_mask_bits(ptr, _mask, _bits)        \
 259 ({                                                              \
 260         const typeof(*ptr) mask = (_mask), bits = (_bits);      \
 261         typeof(*ptr) old, new;                                  \
 262                                                                 \
 263         do {                                                    \
 264                 old = READ_ONCE(*ptr);                  \
 265                 new = (old & ~mask) | bits;                     \
 266         } while (cmpxchg(ptr, old, new) != old);                \
 267                                                                 \
 268         new;                                                    \
 269 })
 270 #endif
 271
 272 #ifndef bit_clear_unless
 273 #define bit_clear_unless(ptr, _clear, _test)    \
 274 ({                                                              \
 275         const typeof(*ptr) clear = (_clear), test = (_test);    \
 276         typeof(*ptr) old, new;                                  \
 277                                                                 \
 278         do {                                                    \
 279                 old = READ_ONCE(*ptr);                  \
 280                 new = old & ~clear;                             \
 281         } while (!(old & test) &&                               \
 282                  cmpxchg(ptr, old, new) != old);                \
 283                                                                 \
 284         !(old & test);                                          \
 285 })
 286 #endif
 287
 288 #ifndef find_last_bit
 289 /**
 290  * find_last_bit - find the last set bit in a memory region
 291  * @addr: The address to start the search at
 292  * @size: The number of bits to search
 293  *
 294  * Returns the bit number of the last set bit, or size.
 295  */
 296 extern unsigned long find_last_bit(const unsigned long *addr,
 297                                    unsigned long size);
 298 #endif
 299
 300 #endif /* __KERNEL__ */
 301 #endif