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