linux/include/linux/bitmap.h
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   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 * The generated code is more efficient when nbits is known at
  32 * compile-time and at most BITS_PER_LONG.
  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_arr32(dst, buf, nbits)          Copy nbits from u32[] buf to dst
  68 *  bitmap_to_arr32(buf, src, nbits)            Copy nbits from buf to u32[] dst
  69 *
  70 * Note, bitmap_zero() and bitmap_fill() operate over the region of
  71 * unsigned longs, that is, bits behind bitmap till the unsigned long
  72 * boundary will be zeroed or filled as well. Consider to use
  73 * bitmap_clear() or bitmap_set() to make explicit zeroing or filling
  74 * respectively.
  75 */
  76
  77/**
  78 * DOC: bitmap bitops
  79 *
  80 * Also the following operations in asm/bitops.h apply to bitmaps.::
  81 *
  82 *  set_bit(bit, addr)                  *addr |= bit
  83 *  clear_bit(bit, addr)                *addr &= ~bit
  84 *  change_bit(bit, addr)               *addr ^= bit
  85 *  test_bit(bit, addr)                 Is bit set in *addr?
  86 *  test_and_set_bit(bit, addr)         Set bit and return old value
  87 *  test_and_clear_bit(bit, addr)       Clear bit and return old value
  88 *  test_and_change_bit(bit, addr)      Change bit and return old value
  89 *  find_first_zero_bit(addr, nbits)    Position first zero bit in *addr
  90 *  find_first_bit(addr, nbits)         Position first set bit in *addr
  91 *  find_next_zero_bit(addr, nbits, bit)
  92 *                                      Position next zero bit in *addr >= bit
  93 *  find_next_bit(addr, nbits, bit)     Position next set bit in *addr >= bit
  94 *  find_next_and_bit(addr1, addr2, nbits, bit)
  95 *                                      Same as find_next_bit, but in
  96 *                                      (*addr1 & *addr2)
  97 *
  98 */
  99
 100/**
 101 * DOC: declare bitmap
 102 * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used
 103 * to declare an array named 'name' of just enough unsigned longs to
 104 * contain all bit positions from 0 to 'bits' - 1.
 105 */
 106
 107/*
 108 * Allocation and deallocation of bitmap.
 109 * Provided in lib/bitmap.c to avoid circular dependency.
 110 */
 111extern unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags);
 112extern unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags);
 113extern void bitmap_free(const unsigned long *bitmap);
 114
 115/*
 116 * lib/bitmap.c provides these functions:
 117 */
 118
 119extern int __bitmap_empty(const unsigned long *bitmap, unsigned int nbits);
 120extern int __bitmap_full(const unsigned long *bitmap, unsigned int nbits);
 121extern int __bitmap_equal(const unsigned long *bitmap1,
 122                          const unsigned long *bitmap2, unsigned int nbits);
 123extern bool __pure __bitmap_or_equal(const unsigned long *src1,
 124                                     const unsigned long *src2,
 125                                     const unsigned long *src3,
 126                                     unsigned int nbits);
 127extern void __bitmap_complement(unsigned long *dst, const unsigned long *src,
 128                        unsigned int nbits);
 129extern void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
 130                                unsigned int shift, unsigned int nbits);
 131extern void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
 132                                unsigned int shift, unsigned int nbits);
 133extern int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
 134                        const unsigned long *bitmap2, unsigned int nbits);
 135extern void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
 136                        const unsigned long *bitmap2, unsigned int nbits);
 137extern void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
 138                        const unsigned long *bitmap2, unsigned int nbits);
 139extern int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
 140                        const unsigned long *bitmap2, unsigned int nbits);
 141extern int __bitmap_intersects(const unsigned long *bitmap1,
 142                        const unsigned long *bitmap2, unsigned int nbits);
 143extern int __bitmap_subset(const unsigned long *bitmap1,
 144                        const unsigned long *bitmap2, unsigned int nbits);
 145extern int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
 146extern void __bitmap_set(unsigned long *map, unsigned int start, int len);
 147extern void __bitmap_clear(unsigned long *map, unsigned int start, int len);
 148
 149extern unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
 150                                                    unsigned long size,
 151                                                    unsigned long start,
 152                                                    unsigned int nr,
 153                                                    unsigned long align_mask,
 154                                                    unsigned long align_offset);
 155
 156/**
 157 * bitmap_find_next_zero_area - find a contiguous aligned zero area
 158 * @map: The address to base the search on
 159 * @size: The bitmap size in bits
 160 * @start: The bitnumber to start searching at
 161 * @nr: The number of zeroed bits we're looking for
 162 * @align_mask: Alignment mask for zero area
 163 *
 164 * The @align_mask should be one less than a power of 2; the effect is that
 165 * the bit offset of all zero areas this function finds is multiples of that
 166 * power of 2. A @align_mask of 0 means no alignment is required.
 167 */
 168static inline unsigned long
 169bitmap_find_next_zero_area(unsigned long *map,
 170                           unsigned long size,
 171                           unsigned long start,
 172                           unsigned int nr,
 173                           unsigned long align_mask)
 174{
 175        return bitmap_find_next_zero_area_off(map, size, start, nr,
 176                                              align_mask, 0);
 177}
 178
 179extern int __bitmap_parse(const char *buf, unsigned int buflen, int is_user,
 180                        unsigned long *dst, int nbits);
 181extern int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,
 182                        unsigned long *dst, int nbits);
 183extern int bitmap_parselist(const char *buf, unsigned long *maskp,
 184                        int nmaskbits);
 185extern int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen,
 186                        unsigned long *dst, int nbits);
 187extern void bitmap_remap(unsigned long *dst, const unsigned long *src,
 188                const unsigned long *old, const unsigned long *new, unsigned int nbits);
 189extern int bitmap_bitremap(int oldbit,
 190                const unsigned long *old, const unsigned long *new, int bits);
 191extern void bitmap_onto(unsigned long *dst, const unsigned long *orig,
 192                const unsigned long *relmap, unsigned int bits);
 193extern void bitmap_fold(unsigned long *dst, const unsigned long *orig,
 194                unsigned int sz, unsigned int nbits);
 195extern int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order);
 196extern void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order);
 197extern int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order);
 198
 199#ifdef __BIG_ENDIAN
 200extern void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits);
 201#else
 202#define bitmap_copy_le bitmap_copy
 203#endif
 204extern unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int ord, unsigned int nbits);
 205extern int bitmap_print_to_pagebuf(bool list, char *buf,
 206                                   const unsigned long *maskp, int nmaskbits);
 207
 208#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
 209#define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
 210
 211/*
 212 * The static inlines below do not handle constant nbits==0 correctly,
 213 * so make such users (should any ever turn up) call the out-of-line
 214 * versions.
 215 */
 216#define small_const_nbits(nbits) \
 217        (__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0)
 218
 219static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
 220{
 221        unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 222        memset(dst, 0, len);
 223}
 224
 225static inline void bitmap_fill(unsigned long *dst, unsigned int nbits)
 226{
 227        unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 228        memset(dst, 0xff, len);
 229}
 230
 231static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
 232                        unsigned int nbits)
 233{
 234        unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
 235        memcpy(dst, src, len);
 236}
 237
 238/*
 239 * Copy bitmap and clear tail bits in last word.
 240 */
 241static inline void bitmap_copy_clear_tail(unsigned long *dst,
 242                const unsigned long *src, unsigned int nbits)
 243{
 244        bitmap_copy(dst, src, nbits);
 245        if (nbits % BITS_PER_LONG)
 246                dst[nbits / BITS_PER_LONG] &= BITMAP_LAST_WORD_MASK(nbits);
 247}
 248
 249/*
 250 * On 32-bit systems bitmaps are represented as u32 arrays internally, and
 251 * therefore conversion is not needed when copying data from/to arrays of u32.
 252 */
 253#if BITS_PER_LONG == 64
 254extern void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf,
 255                                                        unsigned int nbits);
 256extern void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap,
 257                                                        unsigned int nbits);
 258#else
 259#define bitmap_from_arr32(bitmap, buf, nbits)                   \
 260        bitmap_copy_clear_tail((unsigned long *) (bitmap),      \
 261                        (const unsigned long *) (buf), (nbits))
 262#define bitmap_to_arr32(buf, bitmap, nbits)                     \
 263        bitmap_copy_clear_tail((unsigned long *) (buf),         \
 264                        (const unsigned long *) (bitmap), (nbits))
 265#endif
 266
 267static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
 268                        const unsigned long *src2, unsigned int nbits)
 269{
 270        if (small_const_nbits(nbits))
 271                return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 272        return __bitmap_and(dst, src1, src2, nbits);
 273}
 274
 275static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
 276                        const unsigned long *src2, unsigned int nbits)
 277{
 278        if (small_const_nbits(nbits))
 279                *dst = *src1 | *src2;
 280        else
 281                __bitmap_or(dst, src1, src2, nbits);
 282}
 283
 284static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
 285                        const unsigned long *src2, unsigned int nbits)
 286{
 287        if (small_const_nbits(nbits))
 288                *dst = *src1 ^ *src2;
 289        else
 290                __bitmap_xor(dst, src1, src2, nbits);
 291}
 292
 293static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
 294                        const unsigned long *src2, unsigned int nbits)
 295{
 296        if (small_const_nbits(nbits))
 297                return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 298        return __bitmap_andnot(dst, src1, src2, nbits);
 299}
 300
 301static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,
 302                        unsigned int nbits)
 303{
 304        if (small_const_nbits(nbits))
 305                *dst = ~(*src);
 306        else
 307                __bitmap_complement(dst, src, nbits);
 308}
 309
 310#ifdef __LITTLE_ENDIAN
 311#define BITMAP_MEM_ALIGNMENT 8
 312#else
 313#define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long))
 314#endif
 315#define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1)
 316
 317static inline int bitmap_equal(const unsigned long *src1,
 318                        const unsigned long *src2, unsigned int nbits)
 319{
 320        if (small_const_nbits(nbits))
 321                return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
 322        if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 323            IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 324                return !memcmp(src1, src2, nbits / 8);
 325        return __bitmap_equal(src1, src2, nbits);
 326}
 327
 328/**
 329 * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third
 330 * @src1:       Pointer to bitmap 1
 331 * @src2:       Pointer to bitmap 2 will be or'ed with bitmap 1
 332 * @src3:       Pointer to bitmap 3. Compare to the result of *@src1 | *@src2
 333 * @nbits:      number of bits in each of these bitmaps
 334 *
 335 * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise
 336 */
 337static inline bool bitmap_or_equal(const unsigned long *src1,
 338                                   const unsigned long *src2,
 339                                   const unsigned long *src3,
 340                                   unsigned int nbits)
 341{
 342        if (!small_const_nbits(nbits))
 343                return __bitmap_or_equal(src1, src2, src3, nbits);
 344
 345        return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits));
 346}
 347
 348static inline int bitmap_intersects(const unsigned long *src1,
 349                        const unsigned long *src2, unsigned int nbits)
 350{
 351        if (small_const_nbits(nbits))
 352                return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
 353        else
 354                return __bitmap_intersects(src1, src2, nbits);
 355}
 356
 357static inline int bitmap_subset(const unsigned long *src1,
 358                        const unsigned long *src2, unsigned int nbits)
 359{
 360        if (small_const_nbits(nbits))
 361                return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));
 362        else
 363                return __bitmap_subset(src1, src2, nbits);
 364}
 365
 366static inline int bitmap_empty(const unsigned long *src, unsigned nbits)
 367{
 368        if (small_const_nbits(nbits))
 369                return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
 370
 371        return find_first_bit(src, nbits) == nbits;
 372}
 373
 374static inline int bitmap_full(const unsigned long *src, unsigned int nbits)
 375{
 376        if (small_const_nbits(nbits))
 377                return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
 378
 379        return find_first_zero_bit(src, nbits) == nbits;
 380}
 381
 382static __always_inline int bitmap_weight(const unsigned long *src, unsigned int nbits)
 383{
 384        if (small_const_nbits(nbits))
 385                return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
 386        return __bitmap_weight(src, nbits);
 387}
 388
 389static __always_inline void bitmap_set(unsigned long *map, unsigned int start,
 390                unsigned int nbits)
 391{
 392        if (__builtin_constant_p(nbits) && nbits == 1)
 393                __set_bit(start, map);
 394        else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
 395                 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
 396                 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 397                 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 398                memset((char *)map + start / 8, 0xff, nbits / 8);
 399        else
 400                __bitmap_set(map, start, nbits);
 401}
 402
 403static __always_inline void bitmap_clear(unsigned long *map, unsigned int start,
 404                unsigned int nbits)
 405{
 406        if (__builtin_constant_p(nbits) && nbits == 1)
 407                __clear_bit(start, map);
 408        else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
 409                 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
 410                 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
 411                 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
 412                memset((char *)map + start / 8, 0, nbits / 8);
 413        else
 414                __bitmap_clear(map, start, nbits);
 415}
 416
 417static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src,
 418                                unsigned int shift, unsigned int nbits)
 419{
 420        if (small_const_nbits(nbits))
 421                *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift;
 422        else
 423                __bitmap_shift_right(dst, src, shift, nbits);
 424}
 425
 426static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src,
 427                                unsigned int shift, unsigned int nbits)
 428{
 429        if (small_const_nbits(nbits))
 430                *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits);
 431        else
 432                __bitmap_shift_left(dst, src, shift, nbits);
 433}
 434
 435static inline int bitmap_parse(const char *buf, unsigned int buflen,
 436                        unsigned long *maskp, int nmaskbits)
 437{
 438        return __bitmap_parse(buf, buflen, 0, maskp, nmaskbits);
 439}
 440
 441/**
 442 * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.
 443 * @n: u64 value
 444 *
 445 * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit
 446 * integers in 32-bit environment, and 64-bit integers in 64-bit one.
 447 *
 448 * There are four combinations of endianness and length of the word in linux
 449 * ABIs: LE64, BE64, LE32 and BE32.
 450 *
 451 * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in
 452 * bitmaps and therefore don't require any special handling.
 453 *
 454 * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory
 455 * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the
 456 * other hand is represented as an array of 32-bit words and the position of
 457 * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that
 458 * word.  For example, bit #42 is located at 10th position of 2nd word.
 459 * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit
 460 * values in memory as it usually does. But for BE we need to swap hi and lo
 461 * words manually.
 462 *
 463 * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and
 464 * lo parts of u64.  For LE32 it does nothing, and for BE environment it swaps
 465 * hi and lo words, as is expected by bitmap.
 466 */
 467#if __BITS_PER_LONG == 64
 468#define BITMAP_FROM_U64(n) (n)
 469#else
 470#define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \
 471                                ((unsigned long) ((u64)(n) >> 32))
 472#endif
 473
 474/**
 475 * bitmap_from_u64 - Check and swap words within u64.
 476 *  @mask: source bitmap
 477 *  @dst:  destination bitmap
 478 *
 479 * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]``
 480 * to read u64 mask, we will get the wrong word.
 481 * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits,
 482 * but we expect the lower 32-bits of u64.
 483 */
 484static inline void bitmap_from_u64(unsigned long *dst, u64 mask)
 485{
 486        dst[0] = mask & ULONG_MAX;
 487
 488        if (sizeof(mask) > sizeof(unsigned long))
 489                dst[1] = mask >> 32;
 490}
 491
 492#endif /* __ASSEMBLY__ */
 493
 494#endif /* __LINUX_BITMAP_H */
 495