include/linux/bitmap.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __LINUX_BITMAP_H
   3 #define __LINUX_BITMAP_H
   4
   5 #ifndef __ASSEMBLY__
   6
   7 #include <linux/types.h>
   8 #include <linux/bitops.h>
   9 #include <linux/string.h>
  10 #include <linux/kernel.h>
  11
  12 /*
  13  * bitmaps provide bit arrays that consume one or more unsigned
  14  * longs.  The bitmap interface and available operations are listed
  15  * here, in bitmap.h
  16  *
  17  * Function implementations generic to all architectures are in
  18  * lib/bitmap.c.  Functions implementations that are architecture
  19  * specific are in various include/asm-<arch>/bitops.h headers
  20  * and other arch/<arch> specific files.
  21  *
  22  * See lib/bitmap.c for more details.
  23  */
  24
  25 /**
  26  * DOC: bitmap overview
  27  *
  28  * The available bitmap operations and their rough meaning in the
  29  * case that the bitmap is a single unsigned long are thus:
  30  *
  31  * Note that nbits should be always a compile time evaluable constant.
  32  * Otherwise many inlines will generate horrible code.
  33  *
  34  * ::
  35  *
  36  *  bitmap_zero(dst, nbits)                     *dst = 0UL
  37  *  bitmap_fill(dst, nbits)                     *dst = ~0UL
  38  *  bitmap_copy(dst, src, nbits)                *dst = *src
  39  *  bitmap_and(dst, src1, src2, nbits)          *dst = *src1 & *src2
  40  *  bitmap_or(dst, src1, src2, nbits)           *dst = *src1 | *src2
  41  *  bitmap_xor(dst, src1, src2, nbits)          *dst = *src1 ^ *src2
  42  *  bitmap_andnot(dst, src1, src2, nbits)       *dst = *src1 & ~(*src2)
  43  *  bitmap_complement(dst, src, nbits)          *dst = ~(*src)
  44  *  bitmap_equal(src1, src2, nbits)             Are *src1 and *src2 equal?
  45  *  bitmap_intersects(src1, src2, nbits)        Do *src1 and *src2 overlap?
  46  *  bitmap_subset(src1, src2, nbits)            Is *src1 a subset of *src2?
  47  *  bitmap_empty(src, nbits)                    Are all bits zero in *src?
  48  *  bitmap_full(src, nbits)                     Are all bits set in *src?
  49  *  bitmap_weight(src, nbits)                   Hamming Weight: number set bits
  50  *  bitmap_set(dst, pos, nbits)                 Set specified bit area
  51  *  bitmap_clear(dst, pos, nbits)               Clear specified bit area
  52  *  bitmap_find_next_zero_area(buf, len, pos, n, mask)  Find bit free area
  53  *  bitmap_find_next_zero_area_off(buf, len, pos, n, mask)  as above
  54  *  bitmap_shift_right(dst, src, n, nbits)      *dst = *src >> n
  55  *  bitmap_shift_left(dst, src, n, nbits)       *dst = *src << n
  56  *  bitmap_remap(dst, src, old, new, nbits)     *dst = map(old, new)(src)
  57  *  bitmap_bitremap(oldbit, old, new, nbits)    newbit = map(old, new)(oldbit)
  58  *  bitmap_onto(dst, orig, relmap, nbits)       *dst = orig relative to relmap
  59  *  bitmap_fold(dst, orig, sz, nbits)           dst bits = orig bits mod sz
  60  *  bitmap_parse(buf, buflen, dst, nbits)       Parse bitmap dst from kernel buf
  61  *  bitmap_parse_user(ubuf, ulen, dst, nbits)   Parse bitmap dst from user buf
  62  *  bitmap_parselist(buf, dst, nbits)           Parse bitmap dst from kernel buf
  63  *  bitmap_parselist_user(buf, dst, nbits)      Parse bitmap dst from user buf
  64  *  bitmap_find_free_region(bitmap, bits, order)  Find and allocate bit region
  65  *  bitmap_release_region(bitmap, pos, order)   Free specified bit region
  66  *  bitmap_allocate_region(bitmap, pos, order)  Allocate specified bit region
  67  *  bitmap_from_u32array(dst, nbits, buf, nwords)  *dst = *buf (nwords 32b words)
  68  *  bitmap_to_u32array(buf, nwords, src, nbits) *buf = *dst (nwords 32b words)
  69  *
  70  */
  71
  72 /**
  73  * DOC: bitmap bitops
  74  *
  75  * Also the following operations in asm/bitops.h apply to bitmaps.::
  76  *
  77  *  set_bit(bit, addr)                  *addr |= bit
  78  *  clear_bit(bit, addr)                *addr &= ~bit
  79  *  change_bit(bit, addr)               *addr ^= bit
  80  *  test_bit(bit, addr)                 Is bit set in *addr?
  81  *  test_and_set_bit(bit, addr)         Set bit and return old value
  82  *  test_and_clear_bit(bit, addr)       Clear bit and return old value
  83  *  test_and_change_bit(bit, addr)      Change bit and return old value
  84  *  find_first_zero_bit(addr, nbits)    Position first zero bit in *addr
  85  *  find_first_bit(addr, nbits)         Position first set bit in *addr
  86  *  find_next_zero_bit(addr, nbits, bit)  Position next zero bit in *addr >= bit
  87  *  find_next_bit(addr, nbits, bit)     Position next set bit in *addr >= bit
  88  *
  89  */
  90
  91 /**
  92  * DOC: declare bitmap
  93  * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used
  94  * to declare an array named 'name' of just enough unsigned longs to
  95  * contain all bit positions from 0 to 'bits' - 1.
  96  */
  97
  98 /*
  99  * Allocation and deallocation of bitmap.
 100  * Provided in lib/bitmap.c to avoid circular dependency.
 101  */
 102 extern unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags);
 103 extern unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags);
 104 extern void bitmap_free(const unsigned long *bitmap);
 105
 106 /*
 107  * lib/bitmap.c provides these functions:
 108  */
 109
 110 extern int __bitmap_empty(const unsigned long *bitmap, unsigned int nbits);
 111 extern int __bitmap_full(const unsigned long *bitmap, unsigned int nbits);
 112 extern int __bitmap_equal(const unsigned long *bitmap1,
 113                           const unsigned long *bitmap2, unsigned int nbits);
 114 extern void __bitmap_complement(unsigned long *dst, const unsigned long *src,
 115                         unsigned int nbits);
 116 extern void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
 117                                 unsigned int shift, unsigned int nbits);
 118 extern void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
 119                                 unsigned int shift, unsigned int nbits);
 120 extern int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
 121                         const unsigned long *bitmap2, unsigned int nbits);
 122 extern void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
 123                         const unsigned long *bitmap2, unsigned int nbits);
 124 extern void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
 125                         const unsigned long *bitmap2, unsigned int nbits);
 126 extern int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
 127                         const unsigned long *bitmap2, unsigned int nbits);
 128 extern int __bitmap_intersects(const unsigned long *bitmap1,
 129                         const unsigned long *bitmap2, unsigned int nbits);
 130 extern int __bitmap_subset(const unsigned long *bitmap1,
 131                         const unsigned long *bitmap2, unsigned int nbits);
 132 extern int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
 133 extern void __bitmap_set(unsigned long *map, unsigned int start, int len);
 134 extern void __bitmap_clear(unsigned long *map, unsigned int start, int len);
 135
 136 extern unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
 137                                                     unsigned long size,
 138                                                     unsigned long start,
 139                                                     unsigned int nr,
 140                                                     unsigned long align_mask,
 141                                                     unsigned long align_offset);
 142
 143 /**
 144  * bitmap_find_next_zero_area - find a contiguous aligned zero area
 145  * @map: The address to base the search on
 146  * @size: The bitmap size in bits
 147  * @start: The bitnumber to start searching at
 148  * @nr: The number of zeroed bits we're looking for
 149  * @align_mask: Alignment mask for zero area
 150  *
 151  * The @align_mask should be one less than a power of 2; the effect is that
 152  * the bit offset of all zero areas this function finds is multiples of that
 153  * power of 2. A @align_mask of 0 means no alignment is required.
 154  */
 155 static inline unsigned long
 156 bitmap_find_next_zero_area(unsigned long *map,
 157                            unsigned long size,
 158                            unsigned long start,
 159                            unsigned int nr,
 160                            unsigned long align_mask)
 161 {
 162         return bitmap_find_next_zero_area_off(map, size, start, nr,
 163                                               align_mask, 0);
 164 }
 165
 166 extern int __bitmap_parse(const char *buf, unsigned int buflen, int is_user,
 167                         unsigned long *dst, int nbits);
 168 extern int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,
 169                         unsigned long *dst, int nbits);
 170 extern int bitmap_parselist(const char *buf, unsigned long *maskp,
 171                         int nmaskbits);
 172 extern int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen,
 173                         unsigned long *dst, int nbits);
 174 extern void bitmap_remap(unsigned long *dst, const unsigned long *src,
 175                 const unsigned long *old, const unsigned long *new, unsigned int nbits);
 176 extern int bitmap_bitremap(int oldbit,
 177                 const unsigned long *old, const unsigned long *new, int bits);
 178 extern void bitmap_onto(unsigned long *dst, const unsigned long *orig,
 179                 const unsigned long *relmap, unsigned int bits);
 180 extern void bitmap_fold(unsigned long *dst, const unsigned long *orig,
 181                 unsigned int sz, unsigned int nbits);
 182 extern int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order);
 183 extern void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order);
 184 extern int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order);
 185 extern unsigned int bitmap_from_u32array(unsigned long *bitmap,
 186                                          unsigned int nbits,
 187                                          const u32 *buf,
 188                                          unsigned int nwords);
 189 extern unsigned int bitmap_to_u32array(u32 *buf,
 190                                        unsigned int nwords,
 191                                        const unsigned long *bitmap,
 192                                        unsigned int nbits);
 193 #ifdef __BIG_ENDIAN
 194 extern void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits);
 195 #else
 196 #define bitmap_copy_le bitmap_copy
 197 #endif
 198 extern unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int ord, unsigned int nbits);
 199 extern int bitmap_print_to_pagebuf(bool list, char *buf,
 200                                    const unsigned long *maskp, int nmaskbits);
 201
 202 #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
 203 #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
 204
 205 /*
 206  * The static inlines below do not handle constant nbits==0 correctly,
 207  * so make such users (should any ever turn up) call the out-of-line
 208  * versions.
 209  */
 210 #define small_const_nbits(nbits) \
 211         (__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0)
 212
 213 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
 214 {
 215         if (small_const_nbits(nbits))
 216                 *dst = 0UL;
 217         else {
 218                 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 219                 memset(dst, 0, len);
 220         }
 221 }
 222
 223 static inline void bitmap_fill(unsigned long *dst, unsigned int nbits)
 224 {
 225         unsigned int nlongs = BITS_TO_LONGS(nbits);
 226         if (!small_const_nbits(nbits)) {
 227                 unsigned int len = (nlongs - 1) * sizeof(unsigned long);
 228                 memset(dst, 0xff,  len);
 229         }
 230         dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
 231 }
 232
 233 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
 234                         unsigned int nbits)
 235 {
 236         if (small_const_nbits(nbits))
 237                 *dst = *src;
 238         else {
 239                 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 240                 memcpy(dst, src, len);
 241         }
 242 }
 243
 244 static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
 245                         const unsigned long *src2, unsigned int nbits)
 246 {
 247         if (small_const_nbits(nbits))
 248                 return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 249         return __bitmap_and(dst, src1, src2, nbits);
 250 }
 251
 252 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
 253                         const unsigned long *src2, unsigned int nbits)
 254 {
 255         if (small_const_nbits(nbits))
 256                 *dst = *src1 | *src2;
 257         else
 258                 __bitmap_or(dst, src1, src2, nbits);
 259 }
 260
 261 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
 262                         const unsigned long *src2, unsigned int nbits)
 263 {
 264         if (small_const_nbits(nbits))
 265                 *dst = *src1 ^ *src2;
 266         else
 267                 __bitmap_xor(dst, src1, src2, nbits);
 268 }
 269
 270 static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
 271                         const unsigned long *src2, unsigned int nbits)
 272 {
 273         if (small_const_nbits(nbits))
 274                 return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 275         return __bitmap_andnot(dst, src1, src2, nbits);
 276 }
 277
 278 static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,
 279                         unsigned int nbits)
 280 {
 281         if (small_const_nbits(nbits))
 282                 *dst = ~(*src);
 283         else
 284                 __bitmap_complement(dst, src, nbits);
 285 }
 286
 287 #ifdef __LITTLE_ENDIAN
 288 #define BITMAP_MEM_ALIGNMENT 8
 289 #else
 290 #define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long))
 291 #endif
 292 #define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1)
 293
 294 static inline int bitmap_equal(const unsigned long *src1,
 295                         const unsigned long *src2, unsigned int nbits)
 296 {
 297         if (small_const_nbits(nbits))
 298                 return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
 299         if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 300             IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 301                 return !memcmp(src1, src2, nbits / 8);
 302         return __bitmap_equal(src1, src2, nbits);
 303 }
 304
 305 static inline int bitmap_intersects(const unsigned long *src1,
 306                         const unsigned long *src2, unsigned int nbits)
 307 {
 308         if (small_const_nbits(nbits))
 309                 return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 310         else
 311                 return __bitmap_intersects(src1, src2, nbits);
 312 }
 313
 314 static inline int bitmap_subset(const unsigned long *src1,
 315                         const unsigned long *src2, unsigned int nbits)
 316 {
 317         if (small_const_nbits(nbits))
 318                 return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));
 319         else
 320                 return __bitmap_subset(src1, src2, nbits);
 321 }
 322
 323 static inline int bitmap_empty(const unsigned long *src, unsigned nbits)
 324 {
 325         if (small_const_nbits(nbits))
 326                 return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
 327
 328         return find_first_bit(src, nbits) == nbits;
 329 }
 330
 331 static inline int bitmap_full(const unsigned long *src, unsigned int nbits)
 332 {
 333         if (small_const_nbits(nbits))
 334                 return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
 335
 336         return find_first_zero_bit(src, nbits) == nbits;
 337 }
 338
 339 static __always_inline int bitmap_weight(const unsigned long *src, unsigned int nbits)
 340 {
 341         if (small_const_nbits(nbits))
 342                 return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
 343         return __bitmap_weight(src, nbits);
 344 }
 345
 346 static __always_inline void bitmap_set(unsigned long *map, unsigned int start,
 347                 unsigned int nbits)
 348 {
 349         if (__builtin_constant_p(nbits) && nbits == 1)
 350                 __set_bit(start, map);
 351         else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
 352                  IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
 353                  __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 354                  IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 355                 memset((char *)map + start / 8, 0xff, nbits / 8);
 356         else
 357                 __bitmap_set(map, start, nbits);
 358 }
 359
 360 static __always_inline void bitmap_clear(unsigned long *map, unsigned int start,
 361                 unsigned int nbits)
 362 {
 363         if (__builtin_constant_p(nbits) && nbits == 1)
 364                 __clear_bit(start, map);
 365         else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
 366                  IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
 367                  __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 368                  IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 369                 memset((char *)map + start / 8, 0, nbits / 8);
 370         else
 371                 __bitmap_clear(map, start, nbits);
 372 }
 373
 374 static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src,
 375                                 unsigned int shift, unsigned int nbits)
 376 {
 377         if (small_const_nbits(nbits))
 378                 *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift;
 379         else
 380                 __bitmap_shift_right(dst, src, shift, nbits);
 381 }
 382
 383 static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src,
 384                                 unsigned int shift, unsigned int nbits)
 385 {
 386         if (small_const_nbits(nbits))
 387                 *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits);
 388         else
 389                 __bitmap_shift_left(dst, src, shift, nbits);
 390 }
 391
 392 static inline int bitmap_parse(const char *buf, unsigned int buflen,
 393                         unsigned long *maskp, int nmaskbits)
 394 {
 395         return __bitmap_parse(buf, buflen, 0, maskp, nmaskbits);
 396 }
 397
 398 /**
 399  * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.
 400  * @n: u64 value
 401  *
 402  * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit
 403  * integers in 32-bit environment, and 64-bit integers in 64-bit one.
 404  *
 405  * There are four combinations of endianness and length of the word in linux
 406  * ABIs: LE64, BE64, LE32 and BE32.
 407  *
 408  * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in
 409  * bitmaps and therefore don't require any special handling.
 410  *
 411  * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory
 412  * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the
 413  * other hand is represented as an array of 32-bit words and the position of
 414  * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that
 415  * word.  For example, bit #42 is located at 10th position of 2nd word.
 416  * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit
 417  * values in memory as it usually does. But for BE we need to swap hi and lo
 418  * words manually.
 419  *
 420  * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and
 421  * lo parts of u64.  For LE32 it does nothing, and for BE environment it swaps
 422  * hi and lo words, as is expected by bitmap.
 423  */
 424 #if __BITS_PER_LONG == 64
 425 #define BITMAP_FROM_U64(n) (n)
 426 #else
 427 #define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \
 428                                 ((unsigned long) ((u64)(n) >> 32))
 429 #endif
 430
 431 /**
 432  * bitmap_from_u64 - Check and swap words within u64.
 433  *  @mask: source bitmap
 434  *  @dst:  destination bitmap
 435  *
 436  * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]``
 437  * to read u64 mask, we will get the wrong word.
 438  * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits,
 439  * but we expect the lower 32-bits of u64.
 440  */
 441 static inline void bitmap_from_u64(unsigned long *dst, u64 mask)
 442 {
 443         dst[0] = mask & ULONG_MAX;
 444
 445         if (sizeof(mask) > sizeof(unsigned long))
 446                 dst[1] = mask >> 32;
 447 }
 448
 449 #endif /* __ASSEMBLY__ */
 450
 451 #endif /* __LINUX_BITMAP_H */