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_weight_and(src1, src2, nbits) Hamming Weight of and'ed bitmap 55 * bitmap_set(dst, pos, nbits) Set specified bit area 56 * bitmap_clear(dst, pos, nbits) Clear specified bit area 57 * bitmap_find_next_zero_area(buf, len, pos, n, mask) Find bit free area 58 * bitmap_find_next_zero_area_off(buf, len, pos, n, mask, mask_off) as above 59 * bitmap_shift_right(dst, src, n, nbits) *dst = *src >> n 60 * bitmap_shift_left(dst, src, n, nbits) *dst = *src << n 61 * bitmap_cut(dst, src, first, n, nbits) Cut n bits from first, copy rest 62 * bitmap_replace(dst, old, new, mask, nbits) *dst = (*old & ~(*mask)) | (*new & *mask) 63 * bitmap_remap(dst, src, old, new, nbits) *dst = map(old, new)(src) 64 * bitmap_bitremap(oldbit, old, new, nbits) newbit = map(old, new)(oldbit) 65 * bitmap_onto(dst, orig, relmap, nbits) *dst = orig relative to relmap 66 * bitmap_fold(dst, orig, sz, nbits) dst bits = orig bits mod sz 67 * bitmap_parse(buf, buflen, dst, nbits) Parse bitmap dst from kernel buf 68 * bitmap_parse_user(ubuf, ulen, dst, nbits) Parse bitmap dst from user buf 69 * bitmap_parselist(buf, dst, nbits) Parse bitmap dst from kernel buf 70 * bitmap_parselist_user(buf, dst, nbits) Parse bitmap dst from user buf 71 * bitmap_find_free_region(bitmap, bits, order) Find and allocate bit region 72 * bitmap_release_region(bitmap, pos, order) Free specified bit region 73 * bitmap_allocate_region(bitmap, pos, order) Allocate specified bit region 74 * bitmap_from_arr32(dst, buf, nbits) Copy nbits from u32[] buf to dst 75 * bitmap_from_arr64(dst, buf, nbits) Copy nbits from u64[] buf to dst 76 * bitmap_to_arr32(buf, src, nbits) Copy nbits from buf to u32[] dst 77 * bitmap_to_arr64(buf, src, nbits) Copy nbits from buf to u64[] dst 78 * bitmap_get_value8(map, start) Get 8bit value from map at start 79 * bitmap_set_value8(map, value, start) Set 8bit value to map at start 80 * 81 * Note, bitmap_zero() and bitmap_fill() operate over the region of 82 * unsigned longs, that is, bits behind bitmap till the unsigned long 83 * boundary will be zeroed or filled as well. Consider to use 84 * bitmap_clear() or bitmap_set() to make explicit zeroing or filling 85 * respectively. 86 */ 87 88 /** 89 * DOC: bitmap bitops 90 * 91 * Also the following operations in asm/bitops.h apply to bitmaps.:: 92 * 93 * set_bit(bit, addr) *addr |= bit 94 * clear_bit(bit, addr) *addr &= ~bit 95 * change_bit(bit, addr) *addr ^= bit 96 * test_bit(bit, addr) Is bit set in *addr? 97 * test_and_set_bit(bit, addr) Set bit and return old value 98 * test_and_clear_bit(bit, addr) Clear bit and return old value 99 * test_and_change_bit(bit, addr) Change bit and return old value 100 * find_first_zero_bit(addr, nbits) Position first zero bit in *addr 101 * find_first_bit(addr, nbits) Position first set bit in *addr 102 * find_next_zero_bit(addr, nbits, bit) 103 * Position next zero bit in *addr >= bit 104 * find_next_bit(addr, nbits, bit) Position next set bit in *addr >= bit 105 * find_next_and_bit(addr1, addr2, nbits, bit) 106 * Same as find_next_bit, but in 107 * (*addr1 & *addr2) 108 * 109 */ 110 111 /** 112 * DOC: declare bitmap 113 * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used 114 * to declare an array named 'name' of just enough unsigned longs to 115 * contain all bit positions from 0 to 'bits' - 1. 116 */ 117 118 /* 119 * Allocation and deallocation of bitmap. 120 * Provided in lib/bitmap.c to avoid circular dependency. 121 */ 122 unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags); 123 unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags); 124 unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node); 125 unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node); 126 void bitmap_free(const unsigned long *bitmap); 127 128 /* Managed variants of the above. */ 129 unsigned long *devm_bitmap_alloc(struct device *dev, 130 unsigned int nbits, gfp_t flags); 131 unsigned long *devm_bitmap_zalloc(struct device *dev, 132 unsigned int nbits, gfp_t flags); 133 134 /* 135 * lib/bitmap.c provides these functions: 136 */ 137 138 bool __bitmap_equal(const unsigned long *bitmap1, 139 const unsigned long *bitmap2, unsigned int nbits); 140 bool __pure __bitmap_or_equal(const unsigned long *src1, 141 const unsigned long *src2, 142 const unsigned long *src3, 143 unsigned int nbits); 144 void __bitmap_complement(unsigned long *dst, const unsigned long *src, 145 unsigned int nbits); 146 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, 147 unsigned int shift, unsigned int nbits); 148 void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, 149 unsigned int shift, unsigned int nbits); 150 void bitmap_cut(unsigned long *dst, const unsigned long *src, 151 unsigned int first, unsigned int cut, unsigned int nbits); 152 bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, 153 const unsigned long *bitmap2, unsigned int nbits); 154 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, 155 const unsigned long *bitmap2, unsigned int nbits); 156 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, 157 const unsigned long *bitmap2, unsigned int nbits); 158 bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, 159 const unsigned long *bitmap2, unsigned int nbits); 160 void __bitmap_replace(unsigned long *dst, 161 const unsigned long *old, const unsigned long *new, 162 const unsigned long *mask, unsigned int nbits); 163 bool __bitmap_intersects(const unsigned long *bitmap1, 164 const unsigned long *bitmap2, unsigned int nbits); 165 bool __bitmap_subset(const unsigned long *bitmap1, 166 const unsigned long *bitmap2, unsigned int nbits); 167 unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits); 168 unsigned int __bitmap_weight_and(const unsigned long *bitmap1, 169 const unsigned long *bitmap2, unsigned int nbits); 170 void __bitmap_set(unsigned long *map, unsigned int start, int len); 171 void __bitmap_clear(unsigned long *map, unsigned int start, int len); 172 173 unsigned long bitmap_find_next_zero_area_off(unsigned long *map, 174 unsigned long size, 175 unsigned long start, 176 unsigned int nr, 177 unsigned long align_mask, 178 unsigned long align_offset); 179 180 /** 181 * bitmap_find_next_zero_area - find a contiguous aligned zero area 182 * @map: The address to base the search on 183 * @size: The bitmap size in bits 184 * @start: The bitnumber to start searching at 185 * @nr: The number of zeroed bits we're looking for 186 * @align_mask: Alignment mask for zero area 187 * 188 * The @align_mask should be one less than a power of 2; the effect is that 189 * the bit offset of all zero areas this function finds is multiples of that 190 * power of 2. A @align_mask of 0 means no alignment is required. 191 */ 192 static inline unsigned long 193 bitmap_find_next_zero_area(unsigned long *map, 194 unsigned long size, 195 unsigned long start, 196 unsigned int nr, 197 unsigned long align_mask) 198 { 199 return bitmap_find_next_zero_area_off(map, size, start, nr, 200 align_mask, 0); 201 } 202 203 int bitmap_parse(const char *buf, unsigned int buflen, 204 unsigned long *dst, int nbits); 205 int bitmap_parse_user(const char __user *ubuf, unsigned int ulen, 206 unsigned long *dst, int nbits); 207 int bitmap_parselist(const char *buf, unsigned long *maskp, 208 int nmaskbits); 209 int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen, 210 unsigned long *dst, int nbits); 211 void bitmap_remap(unsigned long *dst, const unsigned long *src, 212 const unsigned long *old, const unsigned long *new, unsigned int nbits); 213 int bitmap_bitremap(int oldbit, 214 const unsigned long *old, const unsigned long *new, int bits); 215 void bitmap_onto(unsigned long *dst, const unsigned long *orig, 216 const unsigned long *relmap, unsigned int bits); 217 void bitmap_fold(unsigned long *dst, const unsigned long *orig, 218 unsigned int sz, unsigned int nbits); 219 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order); 220 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order); 221 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order); 222 223 #ifdef __BIG_ENDIAN 224 void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits); 225 #else 226 #define bitmap_copy_le bitmap_copy 227 #endif 228 int bitmap_print_to_pagebuf(bool list, char *buf, 229 const unsigned long *maskp, int nmaskbits); 230 231 extern int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp, 232 int nmaskbits, loff_t off, size_t count); 233 234 extern int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp, 235 int nmaskbits, loff_t off, size_t count); 236 237 #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) 238 #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) 239 240 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits) 241 { 242 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 243 244 if (small_const_nbits(nbits)) 245 *dst = 0; 246 else 247 memset(dst, 0, len); 248 } 249 250 static inline void bitmap_fill(unsigned long *dst, unsigned int nbits) 251 { 252 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 253 254 if (small_const_nbits(nbits)) 255 *dst = ~0UL; 256 else 257 memset(dst, 0xff, len); 258 } 259 260 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src, 261 unsigned int nbits) 262 { 263 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 264 265 if (small_const_nbits(nbits)) 266 *dst = *src; 267 else 268 memcpy(dst, src, len); 269 } 270 271 /* 272 * Copy bitmap and clear tail bits in last word. 273 */ 274 static inline void bitmap_copy_clear_tail(unsigned long *dst, 275 const unsigned long *src, unsigned int nbits) 276 { 277 bitmap_copy(dst, src, nbits); 278 if (nbits % BITS_PER_LONG) 279 dst[nbits / BITS_PER_LONG] &= BITMAP_LAST_WORD_MASK(nbits); 280 } 281 282 /* 283 * On 32-bit systems bitmaps are represented as u32 arrays internally. On LE64 284 * machines the order of hi and lo parts of numbers match the bitmap structure. 285 * In both cases conversion is not needed when copying data from/to arrays of 286 * u32. But in LE64 case, typecast in bitmap_copy_clear_tail() may lead 287 * to out-of-bound access. To avoid that, both LE and BE variants of 64-bit 288 * architectures are not using bitmap_copy_clear_tail(). 289 */ 290 #if BITS_PER_LONG == 64 291 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, 292 unsigned int nbits); 293 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, 294 unsigned int nbits); 295 #else 296 #define bitmap_from_arr32(bitmap, buf, nbits) \ 297 bitmap_copy_clear_tail((unsigned long *) (bitmap), \ 298 (const unsigned long *) (buf), (nbits)) 299 #define bitmap_to_arr32(buf, bitmap, nbits) \ 300 bitmap_copy_clear_tail((unsigned long *) (buf), \ 301 (const unsigned long *) (bitmap), (nbits)) 302 #endif 303 304 /* 305 * On 64-bit systems bitmaps are represented as u64 arrays internally. So, 306 * the conversion is not needed when copying data from/to arrays of u64. 307 */ 308 #if BITS_PER_LONG == 32 309 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 443 unsigned long bitmap_weight_and(const unsigned long *src1, 444 const unsigned long *src2, unsigned int nbits) 445 { 446 if (small_const_nbits(nbits)) 447 return hweight_long(*src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)); 448 return __bitmap_weight_and(src1, src2, nbits); 449 } 450 451 static __always_inline void bitmap_set(unsigned long *map, unsigned int start, 452 unsigned int nbits) 453 { 454 if (__builtin_constant_p(nbits) && nbits == 1) 455 __set_bit(start, map); 456 else if (small_const_nbits(start + nbits)) 457 *map |= GENMASK(start + nbits - 1, start); 458 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) && 459 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) && 460 __builtin_constant_p(nbits & BITMAP_MEM_MASK) && 461 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 462 memset((char *)map + start / 8, 0xff, nbits / 8); 463 else 464 __bitmap_set(map, start, nbits); 465 } 466 467 static __always_inline void bitmap_clear(unsigned long *map, unsigned int start, 468 unsigned int nbits) 469 { 470 if (__builtin_constant_p(nbits) && nbits == 1) 471 __clear_bit(start, map); 472 else if (small_const_nbits(start + nbits)) 473 *map &= ~GENMASK(start + nbits - 1, start); 474 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) && 475 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) && 476 __builtin_constant_p(nbits & BITMAP_MEM_MASK) && 477 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 478 memset((char *)map + start / 8, 0, nbits / 8); 479 else 480 __bitmap_clear(map, start, nbits); 481 } 482 483 static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src, 484 unsigned int shift, unsigned int nbits) 485 { 486 if (small_const_nbits(nbits)) 487 *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift; 488 else 489 __bitmap_shift_right(dst, src, shift, nbits); 490 } 491 492 static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src, 493 unsigned int shift, unsigned int nbits) 494 { 495 if (small_const_nbits(nbits)) 496 *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits); 497 else 498 __bitmap_shift_left(dst, src, shift, nbits); 499 } 500 501 static inline void bitmap_replace(unsigned long *dst, 502 const unsigned long *old, 503 const unsigned long *new, 504 const unsigned long *mask, 505 unsigned int nbits) 506 { 507 if (small_const_nbits(nbits)) 508 *dst = (*old & ~(*mask)) | (*new & *mask); 509 else 510 __bitmap_replace(dst, old, new, mask, nbits); 511 } 512 513 static inline void bitmap_next_set_region(unsigned long *bitmap, 514 unsigned int *rs, unsigned int *re, 515 unsigned int end) 516 { 517 *rs = find_next_bit(bitmap, end, *rs); 518 *re = find_next_zero_bit(bitmap, end, *rs + 1); 519 } 520 521 /** 522 * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap. 523 * @n: u64 value 524 * 525 * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit 526 * integers in 32-bit environment, and 64-bit integers in 64-bit one. 527 * 528 * There are four combinations of endianness and length of the word in linux 529 * ABIs: LE64, BE64, LE32 and BE32. 530 * 531 * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in 532 * bitmaps and therefore don't require any special handling. 533 * 534 * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory 535 * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the 536 * other hand is represented as an array of 32-bit words and the position of 537 * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that 538 * word. For example, bit #42 is located at 10th position of 2nd word. 539 * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit 540 * values in memory as it usually does. But for BE we need to swap hi and lo 541 * words manually. 542 * 543 * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and 544 * lo parts of u64. For LE32 it does nothing, and for BE environment it swaps 545 * hi and lo words, as is expected by bitmap. 546 */ 547 #if __BITS_PER_LONG == 64 548 #define BITMAP_FROM_U64(n) (n) 549 #else 550 #define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \ 551 ((unsigned long) ((u64)(n) >> 32)) 552 #endif 553 554 /** 555 * bitmap_from_u64 - Check and swap words within u64. 556 * @mask: source bitmap 557 * @dst: destination bitmap 558 * 559 * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]`` 560 * to read u64 mask, we will get the wrong word. 561 * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits, 562 * but we expect the lower 32-bits of u64. 563 */ 564 static inline void bitmap_from_u64(unsigned long *dst, u64 mask) 565 { 566 bitmap_from_arr64(dst, &mask, 64); 567 } 568 569 /** 570 * bitmap_get_value8 - get an 8-bit value within a memory region 571 * @map: address to the bitmap memory region 572 * @start: bit offset of the 8-bit value; must be a multiple of 8 573 * 574 * Returns the 8-bit value located at the @start bit offset within the @src 575 * memory region. 576 */ 577 static inline unsigned long bitmap_get_value8(const unsigned long *map, 578 unsigned long start) 579 { 580 const size_t index = BIT_WORD(start); 581 const unsigned long offset = start % BITS_PER_LONG; 582 583 return (map[index] >> offset) & 0xFF; 584 } 585 586 /** 587 * bitmap_set_value8 - set an 8-bit value within a memory region 588 * @map: address to the bitmap memory region 589 * @value: the 8-bit value; values wider than 8 bits may clobber bitmap 590 * @start: bit offset of the 8-bit value; must be a multiple of 8 591 */ 592 static inline void bitmap_set_value8(unsigned long *map, unsigned long value, 593 unsigned long start) 594 { 595 const size_t index = BIT_WORD(start); 596 const unsigned long offset = start % BITS_PER_LONG; 597 598 map[index] &= ~(0xFFUL << offset); 599 map[index] |= value << offset; 600 } 601 602 #endif /* __ASSEMBLY__ */ 603 604 #endif /* __LINUX_BITMAP_H */ 605