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 unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int ord, unsigned int nbits); 229 int bitmap_print_to_pagebuf(bool list, char *buf, 230 const unsigned long *maskp, int nmaskbits); 231 232 extern int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp, 233 int nmaskbits, loff_t off, size_t count); 234 235 extern int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp, 236 int nmaskbits, loff_t off, size_t count); 237 238 #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) 239 #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) 240 241 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits) 242 { 243 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 244 245 if (small_const_nbits(nbits)) 246 *dst = 0; 247 else 248 memset(dst, 0, len); 249 } 250 251 static inline void bitmap_fill(unsigned long *dst, unsigned int nbits) 252 { 253 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 254 255 if (small_const_nbits(nbits)) 256 *dst = ~0UL; 257 else 258 memset(dst, 0xff, len); 259 } 260 261 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src, 262 unsigned int nbits) 263 { 264 unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); 265 266 if (small_const_nbits(nbits)) 267 *dst = *src; 268 else 269 memcpy(dst, src, len); 270 } 271 272 /* 273 * Copy bitmap and clear tail bits in last word. 274 */ 275 static inline void bitmap_copy_clear_tail(unsigned long *dst, 276 const unsigned long *src, unsigned int nbits) 277 { 278 bitmap_copy(dst, src, nbits); 279 if (nbits % BITS_PER_LONG) 280 dst[nbits / BITS_PER_LONG] &= BITMAP_LAST_WORD_MASK(nbits); 281 } 282 283 /* 284 * On 32-bit systems bitmaps are represented as u32 arrays internally. On LE64 285 * machines the order of hi and lo parts of numbers match the bitmap structure. 286 * In both cases conversion is not needed when copying data from/to arrays of 287 * u32. But in LE64 case, typecast in bitmap_copy_clear_tail() may lead 288 * to out-of-bound access. To avoid that, both LE and BE variants of 64-bit 289 * architectures are not using bitmap_copy_clear_tail(). 290 */ 291 #if BITS_PER_LONG == 64 292 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, 293 unsigned int nbits); 294 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, 295 unsigned int nbits); 296 #else 297 #define bitmap_from_arr32(bitmap, buf, nbits) \ 298 bitmap_copy_clear_tail((unsigned long *) (bitmap), \ 299 (const unsigned long *) (buf), (nbits)) 300 #define bitmap_to_arr32(buf, bitmap, nbits) \ 301 bitmap_copy_clear_tail((unsigned long *) (buf), \ 302 (const unsigned long *) (bitmap), (nbits)) 303 #endif 304 305 /* 306 * On 64-bit systems bitmaps are represented as u64 arrays internally. On LE32 307 * machines the order of hi and lo parts of numbers match the bitmap structure. 308 * In both cases conversion is not needed when copying data from/to arrays of 309 * u64. 310 */ 311 #if (BITS_PER_LONG == 32) && defined(__BIG_ENDIAN) 312 void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits); 313 void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits); 314 #else 315 #define bitmap_from_arr64(bitmap, buf, nbits) \ 316 bitmap_copy_clear_tail((unsigned long *)(bitmap), (const unsigned long *)(buf), (nbits)) 317 #define bitmap_to_arr64(buf, bitmap, nbits) \ 318 bitmap_copy_clear_tail((unsigned long *)(buf), (const unsigned long *)(bitmap), (nbits)) 319 #endif 320 321 static inline bool bitmap_and(unsigned long *dst, const unsigned long *src1, 322 const unsigned long *src2, unsigned int nbits) 323 { 324 if (small_const_nbits(nbits)) 325 return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0; 326 return __bitmap_and(dst, src1, src2, nbits); 327 } 328 329 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1, 330 const unsigned long *src2, unsigned int nbits) 331 { 332 if (small_const_nbits(nbits)) 333 *dst = *src1 | *src2; 334 else 335 __bitmap_or(dst, src1, src2, nbits); 336 } 337 338 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1, 339 const unsigned long *src2, unsigned int nbits) 340 { 341 if (small_const_nbits(nbits)) 342 *dst = *src1 ^ *src2; 343 else 344 __bitmap_xor(dst, src1, src2, nbits); 345 } 346 347 static inline bool bitmap_andnot(unsigned long *dst, const unsigned long *src1, 348 const unsigned long *src2, unsigned int nbits) 349 { 350 if (small_const_nbits(nbits)) 351 return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0; 352 return __bitmap_andnot(dst, src1, src2, nbits); 353 } 354 355 static inline void bitmap_complement(unsigned long *dst, const unsigned long *src, 356 unsigned int nbits) 357 { 358 if (small_const_nbits(nbits)) 359 *dst = ~(*src); 360 else 361 __bitmap_complement(dst, src, nbits); 362 } 363 364 #ifdef __LITTLE_ENDIAN 365 #define BITMAP_MEM_ALIGNMENT 8 366 #else 367 #define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long)) 368 #endif 369 #define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1) 370 371 static inline bool bitmap_equal(const unsigned long *src1, 372 const unsigned long *src2, unsigned int nbits) 373 { 374 if (small_const_nbits(nbits)) 375 return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits)); 376 if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) && 377 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 378 return !memcmp(src1, src2, nbits / 8); 379 return __bitmap_equal(src1, src2, nbits); 380 } 381 382 /** 383 * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third 384 * @src1: Pointer to bitmap 1 385 * @src2: Pointer to bitmap 2 will be or'ed with bitmap 1 386 * @src3: Pointer to bitmap 3. Compare to the result of *@src1 | *@src2 387 * @nbits: number of bits in each of these bitmaps 388 * 389 * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise 390 */ 391 static inline bool bitmap_or_equal(const unsigned long *src1, 392 const unsigned long *src2, 393 const unsigned long *src3, 394 unsigned int nbits) 395 { 396 if (!small_const_nbits(nbits)) 397 return __bitmap_or_equal(src1, src2, src3, nbits); 398 399 return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits)); 400 } 401 402 static inline bool bitmap_intersects(const unsigned long *src1, 403 const unsigned long *src2, 404 unsigned int nbits) 405 { 406 if (small_const_nbits(nbits)) 407 return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0; 408 else 409 return __bitmap_intersects(src1, src2, nbits); 410 } 411 412 static inline bool bitmap_subset(const unsigned long *src1, 413 const unsigned long *src2, unsigned int nbits) 414 { 415 if (small_const_nbits(nbits)) 416 return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits)); 417 else 418 return __bitmap_subset(src1, src2, nbits); 419 } 420 421 static inline bool bitmap_empty(const unsigned long *src, unsigned nbits) 422 { 423 if (small_const_nbits(nbits)) 424 return ! (*src & BITMAP_LAST_WORD_MASK(nbits)); 425 426 return find_first_bit(src, nbits) == nbits; 427 } 428 429 static inline bool bitmap_full(const unsigned long *src, unsigned int nbits) 430 { 431 if (small_const_nbits(nbits)) 432 return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits)); 433 434 return find_first_zero_bit(src, nbits) == nbits; 435 } 436 437 static __always_inline 438 unsigned int bitmap_weight(const unsigned long *src, unsigned int nbits) 439 { 440 if (small_const_nbits(nbits)) 441 return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits)); 442 return __bitmap_weight(src, nbits); 443 } 444 445 static __always_inline 446 unsigned long bitmap_weight_and(const unsigned long *src1, 447 const unsigned long *src2, unsigned int nbits) 448 { 449 if (small_const_nbits(nbits)) 450 return hweight_long(*src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)); 451 return __bitmap_weight_and(src1, src2, nbits); 452 } 453 454 static __always_inline void bitmap_set(unsigned long *map, unsigned int start, 455 unsigned int nbits) 456 { 457 if (__builtin_constant_p(nbits) && nbits == 1) 458 __set_bit(start, map); 459 else if (small_const_nbits(start + nbits)) 460 *map |= GENMASK(start + nbits - 1, start); 461 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) && 462 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) && 463 __builtin_constant_p(nbits & BITMAP_MEM_MASK) && 464 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 465 memset((char *)map + start / 8, 0xff, nbits / 8); 466 else 467 __bitmap_set(map, start, nbits); 468 } 469 470 static __always_inline void bitmap_clear(unsigned long *map, unsigned int start, 471 unsigned int nbits) 472 { 473 if (__builtin_constant_p(nbits) && nbits == 1) 474 __clear_bit(start, map); 475 else if (small_const_nbits(start + nbits)) 476 *map &= ~GENMASK(start + nbits - 1, start); 477 else if (__builtin_constant_p(start & BITMAP_MEM_MASK) && 478 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) && 479 __builtin_constant_p(nbits & BITMAP_MEM_MASK) && 480 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT)) 481 memset((char *)map + start / 8, 0, nbits / 8); 482 else 483 __bitmap_clear(map, start, nbits); 484 } 485 486 static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src, 487 unsigned int shift, unsigned int nbits) 488 { 489 if (small_const_nbits(nbits)) 490 *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift; 491 else 492 __bitmap_shift_right(dst, src, shift, nbits); 493 } 494 495 static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src, 496 unsigned int shift, unsigned int nbits) 497 { 498 if (small_const_nbits(nbits)) 499 *dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits); 500 else 501 __bitmap_shift_left(dst, src, shift, nbits); 502 } 503 504 static inline void bitmap_replace(unsigned long *dst, 505 const unsigned long *old, 506 const unsigned long *new, 507 const unsigned long *mask, 508 unsigned int nbits) 509 { 510 if (small_const_nbits(nbits)) 511 *dst = (*old & ~(*mask)) | (*new & *mask); 512 else 513 __bitmap_replace(dst, old, new, mask, nbits); 514 } 515 516 static inline void bitmap_next_set_region(unsigned long *bitmap, 517 unsigned int *rs, unsigned int *re, 518 unsigned int end) 519 { 520 *rs = find_next_bit(bitmap, end, *rs); 521 *re = find_next_zero_bit(bitmap, end, *rs + 1); 522 } 523 524 /** 525 * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap. 526 * @n: u64 value 527 * 528 * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit 529 * integers in 32-bit environment, and 64-bit integers in 64-bit one. 530 * 531 * There are four combinations of endianness and length of the word in linux 532 * ABIs: LE64, BE64, LE32 and BE32. 533 * 534 * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in 535 * bitmaps and therefore don't require any special handling. 536 * 537 * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory 538 * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the 539 * other hand is represented as an array of 32-bit words and the position of 540 * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that 541 * word. For example, bit #42 is located at 10th position of 2nd word. 542 * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit 543 * values in memory as it usually does. But for BE we need to swap hi and lo 544 * words manually. 545 * 546 * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and 547 * lo parts of u64. For LE32 it does nothing, and for BE environment it swaps 548 * hi and lo words, as is expected by bitmap. 549 */ 550 #if __BITS_PER_LONG == 64 551 #define BITMAP_FROM_U64(n) (n) 552 #else 553 #define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \ 554 ((unsigned long) ((u64)(n) >> 32)) 555 #endif 556 557 /** 558 * bitmap_from_u64 - Check and swap words within u64. 559 * @mask: source bitmap 560 * @dst: destination bitmap 561 * 562 * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]`` 563 * to read u64 mask, we will get the wrong word. 564 * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits, 565 * but we expect the lower 32-bits of u64. 566 */ 567 static inline void bitmap_from_u64(unsigned long *dst, u64 mask) 568 { 569 bitmap_from_arr64(dst, &mask, 64); 570 } 571 572 /** 573 * bitmap_get_value8 - get an 8-bit value within a memory region 574 * @map: address to the bitmap memory region 575 * @start: bit offset of the 8-bit value; must be a multiple of 8 576 * 577 * Returns the 8-bit value located at the @start bit offset within the @src 578 * memory region. 579 */ 580 static inline unsigned long bitmap_get_value8(const unsigned long *map, 581 unsigned long start) 582 { 583 const size_t index = BIT_WORD(start); 584 const unsigned long offset = start % BITS_PER_LONG; 585 586 return (map[index] >> offset) & 0xFF; 587 } 588 589 /** 590 * bitmap_set_value8 - set an 8-bit value within a memory region 591 * @map: address to the bitmap memory region 592 * @value: the 8-bit value; values wider than 8 bits may clobber bitmap 593 * @start: bit offset of the 8-bit value; must be a multiple of 8 594 */ 595 static inline void bitmap_set_value8(unsigned long *map, unsigned long value, 596 unsigned long start) 597 { 598 const size_t index = BIT_WORD(start); 599 const unsigned long offset = start % BITS_PER_LONG; 600 601 map[index] &= ~(0xFFUL << offset); 602 map[index] |= value << offset; 603 } 604 605 #endif /* __ASSEMBLY__ */ 606 607 #endif /* __LINUX_BITMAP_H */ 608