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/align.h> 8 #include <linux/bitops.h> 9 #include <linux/find.h> 10 #include <linux/limits.h> 11 #include <linux/string.h> 12 #include <linux/types.h> 13 14 struct device; 15 16 /* 17 * bitmaps provide bit arrays that consume one or more unsigned 18 * longs. The bitmap interface and available operations are listed 19 * here, in bitmap.h 20 * 21 * Function implementations generic to all architectures are in 22 * lib/bitmap.c. Functions implementations that are architecture 23 * specific are in various include/asm-<arch>/bitops.h headers 24 * and other arch/<arch> specific files. 25 * 26 * See lib/bitmap.c for more details. 27 */ 28 29 /** 30 * DOC: bitmap overview 31 * 32 * The available bitmap operations and their rough meaning in the 33 * case that the bitmap is a single unsigned long are thus: 34 * 35 * The generated code is more efficient when nbits is known at 36 * compile-time and at most BITS_PER_LONG. 37 * 38 * :: 39 * 40 * bitmap_zero(dst, nbits) *dst = 0UL 41 * bitmap_fill(dst, nbits) *dst = ~0UL 42 * bitmap_copy(dst, src, nbits) *dst = *src 43 * bitmap_and(dst, src1, src2, nbits) *dst = *src1 & *src2 44 * bitmap_or(dst, src1, src2, nbits) *dst = *src1 | *src2 45 * bitmap_xor(dst, src1, src2, nbits) *dst = *src1 ^ *src2 46 * bitmap_andnot(dst, src1, src2, nbits) *dst = *src1 & ~(*src2) 47 * bitmap_complement(dst, src, nbits) *dst = ~(*src) 48 * bitmap_equal(src1, src2, nbits) Are *src1 and *src2 equal? 49 * bitmap_intersects(src1, src2, nbits) Do *src1 and *src2 overlap? 50 * bitmap_subset(src1, src2, nbits) Is *src1 a subset of *src2? 51 * bitmap_empty(src, nbits) Are all bits zero in *src? 52 * bitmap_full(src, nbits) Are all bits set in *src? 53 * bitmap_weight(src, nbits) Hamming Weight: number set bits 54 * bitmap_set(dst, pos, nbits) Set specified bit area 55 * bitmap_clear(dst, pos, nbits) Clear specified bit area 56 * bitmap_find_next_zero_area(buf, len, pos, n, mask) Find bit free area 57 * bitmap_find_next_zero_area_off(buf, len, pos, n, mask, mask_off) as above 58 * bitmap_shift_right(dst, src, n, nbits) *dst = *src >> n 59 * bitmap_shift_left(dst, src, n, nbits) *dst = *src << n 60 * bitmap_cut(dst, src, first, n, nbits) Cut n bits from first, copy rest 61 * bitmap_replace(dst, old, new, mask, nbits) *dst = (*old & ~(*mask)) | (*new & *mask) 62 * bitmap_remap(dst, src, old, new, nbits) *dst = map(old, new)(src) 63 * bitmap_bitremap(oldbit, old, new, nbits) newbit = map(old, new)(oldbit) 64 * bitmap_onto(dst, orig, relmap, nbits) *dst = orig relative to relmap 65 * bitmap_fold(dst, orig, sz, nbits) dst bits = orig bits mod sz 66 * bitmap_parse(buf, buflen, dst, nbits) Parse bitmap dst from kernel buf 67 * bitmap_parse_user(ubuf, ulen, dst, nbits) Parse bitmap dst from user buf 68 * bitmap_parselist(buf, dst, nbits) Parse bitmap dst from kernel buf 69 * bitmap_parselist_user(buf, dst, nbits) Parse bitmap dst from user buf 70 * bitmap_find_free_region(bitmap, bits, order) Find and allocate bit region 71 * bitmap_release_region(bitmap, pos, order) Free specified bit region 72 * bitmap_allocate_region(bitmap, pos, order) Allocate specified bit region 73 * bitmap_from_arr32(dst, buf, nbits) Copy nbits from u32[] buf to dst 74 * bitmap_from_arr64(dst, buf, nbits) Copy nbits from u64[] buf to dst 75 * bitmap_to_arr32(buf, src, nbits) Copy nbits from buf to u32[] dst 76 * bitmap_to_arr64(buf, src, nbits) Copy nbits from buf to u64[] dst 77 * bitmap_get_value8(map, start) Get 8bit value from map at start 78 * bitmap_set_value8(map, value, start) Set 8bit value to map at start 79 * 80 * Note, bitmap_zero() and bitmap_fill() operate over the region of 81 * unsigned longs, that is, bits behind bitmap till the unsigned long 82 * boundary will be zeroed or filled as well. Consider to use 83 * bitmap_clear() or bitmap_set() to make explicit zeroing or filling 84 * respectively. 85 */ 86 87 /** 88 * DOC: bitmap bitops 89 * 90 * Also the following operations in asm/bitops.h apply to bitmaps.:: 91 * 92 * set_bit(bit, addr) *addr |= bit 93 * clear_bit(bit, addr) *addr &= ~bit 94 * change_bit(bit, addr) *addr ^= bit 95 * test_bit(bit, addr) Is bit set in *addr? 96 * test_and_set_bit(bit, addr) Set bit and return old value 97 * test_and_clear_bit(bit, addr) Clear bit and return old value 98 * test_and_change_bit(bit, addr) Change bit and return old value 99 * find_first_zero_bit(addr, nbits) Position first zero bit in *addr 100 * find_first_bit(addr, nbits) Position first set bit in *addr 101 * find_next_zero_bit(addr, nbits, bit) 102 * Position next zero bit in *addr >= bit 103 * find_next_bit(addr, nbits, bit) Position next set bit in *addr >= bit 104 * find_next_and_bit(addr1, addr2, nbits, bit) 105 * Same as find_next_bit, but in 106 * (*addr1 & *addr2) 107 * 108 */ 109 110 /** 111 * DOC: declare bitmap 112 * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used 113 * to declare an array named 'name' of just enough unsigned longs to 114 * contain all bit positions from 0 to 'bits' - 1. 115 */ 116 117 /* 118 * Allocation and deallocation of bitmap. 119 * Provided in lib/bitmap.c to avoid circular dependency. 120 */ 121 unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags); 122 unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags); 123 unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node); 124 unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node); 125 void bitmap_free(const unsigned long *bitmap); 126 127 /* Managed variants of the above. */ 128 unsigned long *devm_bitmap_alloc(struct device *dev, 129 unsigned int nbits, gfp_t flags); 130 unsigned long *devm_bitmap_zalloc(struct device *dev, 131 unsigned int nbits, gfp_t flags); 132 133 /* 134 * lib/bitmap.c provides these functions: 135 */ 136 137 bool __bitmap_equal(const unsigned long *bitmap1, 138 const unsigned long *bitmap2, unsigned int nbits); 139 bool __pure __bitmap_or_equal(const unsigned long *src1, 140 const unsigned long *src2, 141 const unsigned long *src3, 142 unsigned int nbits); 143 void __bitmap_complement(unsigned long *dst, const unsigned long *src, 144 unsigned int nbits); 145 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, 146 unsigned int shift, unsigned int nbits); 147 void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, 148 unsigned int shift, unsigned int nbits); 149 void bitmap_cut(unsigned long *dst, const unsigned long *src, 150 unsigned int first, unsigned int cut, unsigned int nbits); 151 bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, 152 const unsigned long *bitmap2, unsigned int nbits); 153 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, 154 const unsigned long *bitmap2, unsigned int nbits); 155 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, 156 const unsigned long *bitmap2, unsigned int nbits); 157 bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, 158 const unsigned long *bitmap2, unsigned int nbits); 159 void __bitmap_replace(unsigned long *dst, 160 const unsigned long *old, const unsigned long *new, 161 const unsigned long *mask, unsigned int nbits); 162 bool __bitmap_intersects(const unsigned long *bitmap1, 163 const unsigned long *bitmap2, unsigned int nbits); 164 bool __bitmap_subset(const unsigned long *bitmap1, 165 const unsigned long *bitmap2, unsigned int nbits); 166 unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits); 167 void __bitmap_set(unsigned long *map, unsigned int start, int len); 168 void __bitmap_clear(unsigned long *map, unsigned int start, int len); 169 170 unsigned long bitmap_find_next_zero_area_off(unsigned long *map, 171 unsigned long size, 172 unsigned long start, 173 unsigned int nr, 174 unsigned long align_mask, 175 unsigned long align_offset); 176 177 /** 178 * bitmap_find_next_zero_area - find a contiguous aligned zero area 179 * @map: The address to base the search on 180 * @size: The bitmap size in bits 181 * @start: The bitnumber to start searching at 182 * @nr: The number of zeroed bits we're looking for 183 * @align_mask: Alignment mask for zero area 184 * 185 * The @align_mask should be one less than a power of 2; the effect is that 186 * the bit offset of all zero areas this function finds is multiples of that 187 * power of 2. A @align_mask of 0 means no alignment is required. 188 */ 189 static inline unsigned long 190 bitmap_find_next_zero_area(unsigned long *map, 191 unsigned long size, 192 unsigned long start, 193 unsigned int nr, 194 unsigned long align_mask) 195 { 196 return bitmap_find_next_zero_area_off(map, size, start, nr, 197 align_mask, 0); 198 } 199 200 int bitmap_parse(const char *buf, unsigned int buflen, 201 unsigned long *dst, int nbits); 202 int bitmap_parse_user(const char __user *ubuf, unsigned int ulen, 203 unsigned long *dst, int nbits); 204 int bitmap_parselist(const char *buf, unsigned long *maskp, 205 int nmaskbits); 206 int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen, 207 unsigned long *dst, int nbits); 208 void bitmap_remap(unsigned long *dst, const unsigned long *src, 209 const unsigned long *old, const unsigned long *new, unsigned int nbits); 210 int bitmap_bitremap(int oldbit, 211 const unsigned long *old, const unsigned long *new, int bits); 212 void bitmap_onto(unsigned long *dst, const unsigned long *orig, 213 const unsigned long *relmap, unsigned int bits); 214 void bitmap_fold(unsigned long *dst, const unsigned long *orig, 215 unsigned int sz, unsigned int nbits); 216 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order); 217 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order); 218 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order); 219 220 #ifdef __BIG_ENDIAN 221 void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits); 222 #else 223 #define bitmap_copy_le bitmap_copy 224 #endif 225 unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int ord, unsigned int nbits); 226 int bitmap_print_to_pagebuf(bool list, char *buf, 227 const unsigned long *maskp, int nmaskbits); 228 229 extern int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp, 230 int nmaskbits, loff_t off, size_t count); 231 232 extern int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp, 233 int nmaskbits, loff_t off, size_t count); 234 235 #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) 236 #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) 237 238 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits) 239 { 240 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 241 242 if (small_const_nbits(nbits)) 243 *dst = 0; 244 else 245 memset(dst, 0, len); 246 } 247 248 static inline void bitmap_fill(unsigned long *dst, unsigned int nbits) 249 { 250 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 251 252 if (small_const_nbits(nbits)) 253 *dst = ~0UL; 254 else 255 memset(dst, 0xff, len); 256 } 257 258 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src, 259 unsigned int nbits) 260 { 261 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 262 263 if (small_const_nbits(nbits)) 264 *dst = *src; 265 else 266 memcpy(dst, src, len); 267 } 268 269 /* 270 * Copy bitmap and clear tail bits in last word. 271 */ 272 static inline void bitmap_copy_clear_tail(unsigned long *dst, 273 const unsigned long *src, unsigned int nbits) 274 { 275 bitmap_copy(dst, src, nbits); 276 if (nbits % BITS_PER_LONG) 277 dst[nbits / BITS_PER_LONG] &= BITMAP_LAST_WORD_MASK(nbits); 278 } 279 280 /* 281 * On 32-bit systems bitmaps are represented as u32 arrays internally. On LE64 282 * machines the order of hi and lo parts of numbers match the bitmap structure. 283 * In both cases conversion is not needed when copying data from/to arrays of 284 * u32. But in LE64 case, typecast in bitmap_copy_clear_tail() may lead 285 * to out-of-bound access. To avoid that, both LE and BE variants of 64-bit 286 * architectures are not using bitmap_copy_clear_tail(). 287 */ 288 #if BITS_PER_LONG == 64 289 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, 290 unsigned int nbits); 291 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, 292 unsigned int nbits); 293 #else 294 #define bitmap_from_arr32(bitmap, buf, nbits) \ 295 bitmap_copy_clear_tail((unsigned long *) (bitmap), \ 296 (const unsigned long *) (buf), (nbits)) 297 #define bitmap_to_arr32(buf, bitmap, nbits) \ 298 bitmap_copy_clear_tail((unsigned long *) (buf), \ 299 (const unsigned long *) (bitmap), (nbits)) 300 #endif 301 302 /* 303 * On 64-bit systems bitmaps are represented as u64 arrays internally. On LE32 304 * machines the order of hi and lo parts of numbers match the bitmap structure. 305 * In both cases conversion is not needed when copying data from/to arrays of 306 * u64. 307 */ 308 #if (BITS_PER_LONG == 32) && defined(__BIG_ENDIAN) 309 void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits); 310 void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits); 311 #else 312 #define bitmap_from_arr64(bitmap, buf, nbits) \ 313 bitmap_copy_clear_tail((unsigned long *)(bitmap), (const unsigned long *)(buf), (nbits)) 314 #define bitmap_to_arr64(buf, bitmap, nbits) \ 315 bitmap_copy_clear_tail((unsigned long *)(buf), (const unsigned long *)(bitmap), (nbits)) 316 #endif 317 318 static inline bool bitmap_and(unsigned long *dst, const unsigned long *src1, 319 const unsigned long *src2, unsigned int nbits) 320 { 321 if (small_const_nbits(nbits)) 322 return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0; 323 return __bitmap_and(dst, src1, src2, nbits); 324 } 325 326 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1, 327 const unsigned long *src2, unsigned int nbits) 328 { 329 if (small_const_nbits(nbits)) 330 *dst = *src1 | *src2; 331 else 332 __bitmap_or(dst, src1, src2, nbits); 333 } 334 335 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1, 336 const unsigned long *src2, unsigned int nbits) 337 { 338 if (small_const_nbits(nbits)) 339 *dst = *src1 ^ *src2; 340 else 341 __bitmap_xor(dst, src1, src2, nbits); 342 } 343 344 static inline bool bitmap_andnot(unsigned long *dst, const unsigned long *src1, 345 const unsigned long *src2, unsigned int nbits) 346 { 347 if (small_const_nbits(nbits)) 348 return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0; 349 return __bitmap_andnot(dst, src1, src2, nbits); 350 } 351 352 static inline void bitmap_complement(unsigned long *dst, const unsigned long *src, 353 unsigned int nbits) 354 { 355 if (small_const_nbits(nbits)) 356 *dst = ~(*src); 357 else 358 __bitmap_complement(dst, src, nbits); 359 } 360 361 #ifdef __LITTLE_ENDIAN 362 #define BITMAP_MEM_ALIGNMENT 8 363 #else 364 #define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long)) 365 #endif 366 #define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1) 367 368 static inline bool bitmap_equal(const unsigned long *src1, 369 const unsigned long *src2, unsigned int nbits) 370 { 371 if (small_const_nbits(nbits)) 372 return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits)); 373 if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) && 374 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 375 return !memcmp(src1, src2, nbits / 8); 376 return __bitmap_equal(src1, src2, nbits); 377 } 378 379 /** 380 * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third 381 * @src1: Pointer to bitmap 1 382 * @src2: Pointer to bitmap 2 will be or'ed with bitmap 1 383 * @src3: Pointer to bitmap 3. Compare to the result of *@src1 | *@src2 384 * @nbits: number of bits in each of these bitmaps 385 * 386 * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise 387 */ 388 static inline bool bitmap_or_equal(const unsigned long *src1, 389 const unsigned long *src2, 390 const unsigned long *src3, 391 unsigned int nbits) 392 { 393 if (!small_const_nbits(nbits)) 394 return __bitmap_or_equal(src1, src2, src3, nbits); 395 396 return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits)); 397 } 398 399 static inline bool bitmap_intersects(const unsigned long *src1, 400 const unsigned long *src2, 401 unsigned int nbits) 402 { 403 if (small_const_nbits(nbits)) 404 return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0; 405 else 406 return __bitmap_intersects(src1, src2, nbits); 407 } 408 409 static inline bool bitmap_subset(const unsigned long *src1, 410 const unsigned long *src2, unsigned int nbits) 411 { 412 if (small_const_nbits(nbits)) 413 return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits)); 414 else 415 return __bitmap_subset(src1, src2, nbits); 416 } 417 418 static inline bool bitmap_empty(const unsigned long *src, unsigned nbits) 419 { 420 if (small_const_nbits(nbits)) 421 return ! (*src & BITMAP_LAST_WORD_MASK(nbits)); 422 423 return find_first_bit(src, nbits) == nbits; 424 } 425 426 static inline bool bitmap_full(const unsigned long *src, unsigned int nbits) 427 { 428 if (small_const_nbits(nbits)) 429 return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits)); 430 431 return find_first_zero_bit(src, nbits) == nbits; 432 } 433 434 static __always_inline 435 unsigned int bitmap_weight(const unsigned long *src, unsigned int nbits) 436 { 437 if (small_const_nbits(nbits)) 438 return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits)); 439 return __bitmap_weight(src, nbits); 440 } 441 442 static __always_inline void bitmap_set(unsigned long *map, unsigned int start, 443 unsigned int nbits) 444 { 445 if (__builtin_constant_p(nbits) && nbits == 1) 446 __set_bit(start, map); 447 else if (small_const_nbits(start + nbits)) 448 *map |= GENMASK(start + nbits - 1, start); 449 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) && 450 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) && 451 __builtin_constant_p(nbits & BITMAP_MEM_MASK) && 452 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 453 memset((char *)map + start / 8, 0xff, nbits / 8); 454 else 455 __bitmap_set(map, start, nbits); 456 } 457 458 static __always_inline void bitmap_clear(unsigned long *map, unsigned int start, 459 unsigned int nbits) 460 { 461 if (__builtin_constant_p(nbits) && nbits == 1) 462 __clear_bit(start, map); 463 else if (small_const_nbits(start + nbits)) 464 *map &= ~GENMASK(start + nbits - 1, start); 465 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) && 466 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) && 467 __builtin_constant_p(nbits & BITMAP_MEM_MASK) && 468 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 469 memset((char *)map + start / 8, 0, nbits / 8); 470 else 471 __bitmap_clear(map, start, nbits); 472 } 473 474 static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src, 475 unsigned int shift, unsigned int nbits) 476 { 477 if (small_const_nbits(nbits)) 478 *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift; 479 else 480 __bitmap_shift_right(dst, src, shift, nbits); 481 } 482 483 static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src, 484 unsigned int shift, unsigned int nbits) 485 { 486 if (small_const_nbits(nbits)) 487 *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits); 488 else 489 __bitmap_shift_left(dst, src, shift, nbits); 490 } 491 492 static inline void bitmap_replace(unsigned long *dst, 493 const unsigned long *old, 494 const unsigned long *new, 495 const unsigned long *mask, 496 unsigned int nbits) 497 { 498 if (small_const_nbits(nbits)) 499 *dst = (*old & ~(*mask)) | (*new & *mask); 500 else 501 __bitmap_replace(dst, old, new, mask, nbits); 502 } 503 504 static inline void bitmap_next_set_region(unsigned long *bitmap, 505 unsigned int *rs, unsigned int *re, 506 unsigned int end) 507 { 508 *rs = find_next_bit(bitmap, end, *rs); 509 *re = find_next_zero_bit(bitmap, end, *rs + 1); 510 } 511 512 /** 513 * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap. 514 * @n: u64 value 515 * 516 * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit 517 * integers in 32-bit environment, and 64-bit integers in 64-bit one. 518 * 519 * There are four combinations of endianness and length of the word in linux 520 * ABIs: LE64, BE64, LE32 and BE32. 521 * 522 * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in 523 * bitmaps and therefore don't require any special handling. 524 * 525 * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory 526 * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the 527 * other hand is represented as an array of 32-bit words and the position of 528 * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that 529 * word. For example, bit #42 is located at 10th position of 2nd word. 530 * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit 531 * values in memory as it usually does. But for BE we need to swap hi and lo 532 * words manually. 533 * 534 * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and 535 * lo parts of u64. For LE32 it does nothing, and for BE environment it swaps 536 * hi and lo words, as is expected by bitmap. 537 */ 538 #if __BITS_PER_LONG == 64 539 #define BITMAP_FROM_U64(n) (n) 540 #else 541 #define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \ 542 ((unsigned long) ((u64)(n) >> 32)) 543 #endif 544 545 /** 546 * bitmap_from_u64 - Check and swap words within u64. 547 * @mask: source bitmap 548 * @dst: destination bitmap 549 * 550 * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]`` 551 * to read u64 mask, we will get the wrong word. 552 * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits, 553 * but we expect the lower 32-bits of u64. 554 */ 555 static inline void bitmap_from_u64(unsigned long *dst, u64 mask) 556 { 557 bitmap_from_arr64(dst, &mask, 64); 558 } 559 560 /** 561 * bitmap_get_value8 - get an 8-bit value within a memory region 562 * @map: address to the bitmap memory region 563 * @start: bit offset of the 8-bit value; must be a multiple of 8 564 * 565 * Returns the 8-bit value located at the @start bit offset within the @src 566 * memory region. 567 */ 568 static inline unsigned long bitmap_get_value8(const unsigned long *map, 569 unsigned long start) 570 { 571 const size_t index = BIT_WORD(start); 572 const unsigned long offset = start % BITS_PER_LONG; 573 574 return (map[index] >> offset) & 0xFF; 575 } 576 577 /** 578 * bitmap_set_value8 - set an 8-bit value within a memory region 579 * @map: address to the bitmap memory region 580 * @value: the 8-bit value; values wider than 8 bits may clobber bitmap 581 * @start: bit offset of the 8-bit value; must be a multiple of 8 582 */ 583 static inline void bitmap_set_value8(unsigned long *map, unsigned long value, 584 unsigned long start) 585 { 586 const size_t index = BIT_WORD(start); 587 const unsigned long offset = start % BITS_PER_LONG; 588 589 map[index] &= ~(0xFFUL << offset); 590 map[index] |= value << offset; 591 } 592 593 #endif /* __ASSEMBLY__ */ 594 595 #endif /* __LINUX_BITMAP_H */ 596