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