/* SPDX-License-Identifier: GPL-2.0 */

  #ifndef __LINUX_BITMAP_H
  #define __LINUX_BITMAP_H
  
  #ifndef __ASSEMBLY__
  
  #include <linux/types.h>
  #include <linux/bitops.h>
  #include <linux/string.h>

  #include <linux/kernel.h>

  
  /*
   * bitmaps provide bit arrays that consume one or more unsigned
   * longs.  The bitmap interface and available operations are listed
   * here, in bitmap.h
   *
   * Function implementations generic to all architectures are in
   * lib/bitmap.c.  Functions implementations that are architecture
   * specific are in various include/asm-<arch>/bitops.h headers
   * and other arch/<arch> specific files.
   *
   * See lib/bitmap.c for more details.
   */

  /**
   * DOC: bitmap overview
   *

   * The available bitmap operations and their rough meaning in the
   * case that the bitmap is a single unsigned long are thus:
   *

   * The generated code is more efficient when nbits is known at
   * compile-time and at most BITS_PER_LONG.

   *

   * ::
   *
   *  bitmap_zero(dst, nbits)                     *dst = 0UL
   *  bitmap_fill(dst, nbits)                     *dst = ~0UL
   *  bitmap_copy(dst, src, nbits)                *dst = *src
   *  bitmap_and(dst, src1, src2, nbits)          *dst = *src1 & *src2
   *  bitmap_or(dst, src1, src2, nbits)           *dst = *src1 | *src2
   *  bitmap_xor(dst, src1, src2, nbits)          *dst = *src1 ^ *src2
   *  bitmap_andnot(dst, src1, src2, nbits)       *dst = *src1 & ~(*src2)
   *  bitmap_complement(dst, src, nbits)          *dst = ~(*src)
   *  bitmap_equal(src1, src2, nbits)             Are *src1 and *src2 equal?
   *  bitmap_intersects(src1, src2, nbits)        Do *src1 and *src2 overlap?
   *  bitmap_subset(src1, src2, nbits)            Is *src1 a subset of *src2?
   *  bitmap_empty(src, nbits)                    Are all bits zero in *src?
   *  bitmap_full(src, nbits)                     Are all bits set in *src?
   *  bitmap_weight(src, nbits)                   Hamming Weight: number set bits
   *  bitmap_set(dst, pos, nbits)                 Set specified bit area
   *  bitmap_clear(dst, pos, nbits)               Clear specified bit area
   *  bitmap_find_next_zero_area(buf, len, pos, n, mask)  Find bit free area

   *  bitmap_find_next_zero_area_off(buf, len, pos, n, mask, mask_off)  as above

   *  bitmap_next_clear_region(map, &start, &end, nbits)  Find next clear region
   *  bitmap_next_set_region(map, &start, &end, nbits)  Find next set region
   *  bitmap_for_each_clear_region(map, rs, re, start, end)
   *  						Iterate over all clear regions
   *  bitmap_for_each_set_region(map, rs, re, start, end)
   *  						Iterate over all set regions

   *  bitmap_shift_right(dst, src, n, nbits)      *dst = *src >> n
   *  bitmap_shift_left(dst, src, n, nbits)       *dst = *src << n

   *  bitmap_cut(dst, src, first, n, nbits)       Cut n bits from first, copy rest

   *  bitmap_replace(dst, old, new, mask, nbits)  *dst = (*old & ~(*mask)) | (*new & *mask)

   *  bitmap_remap(dst, src, old, new, nbits)     *dst = map(old, new)(src)
   *  bitmap_bitremap(oldbit, old, new, nbits)    newbit = map(old, new)(oldbit)
   *  bitmap_onto(dst, orig, relmap, nbits)       *dst = orig relative to relmap
   *  bitmap_fold(dst, orig, sz, nbits)           dst bits = orig bits mod sz
   *  bitmap_parse(buf, buflen, dst, nbits)       Parse bitmap dst from kernel buf
   *  bitmap_parse_user(ubuf, ulen, dst, nbits)   Parse bitmap dst from user buf
   *  bitmap_parselist(buf, dst, nbits)           Parse bitmap dst from kernel buf
   *  bitmap_parselist_user(buf, dst, nbits)      Parse bitmap dst from user buf
   *  bitmap_find_free_region(bitmap, bits, order)  Find and allocate bit region
   *  bitmap_release_region(bitmap, pos, order)   Free specified bit region
   *  bitmap_allocate_region(bitmap, pos, order)  Allocate specified bit region

   *  bitmap_from_arr32(dst, buf, nbits)          Copy nbits from u32[] buf to dst
   *  bitmap_to_arr32(buf, src, nbits)            Copy nbits from buf to u32[] dst

   *  bitmap_get_value8(map, start)               Get 8bit value from map at start
   *  bitmap_set_value8(map, value, start)        Set 8bit value to map at start

   *

   * Note, bitmap_zero() and bitmap_fill() operate over the region of
   * unsigned longs, that is, bits behind bitmap till the unsigned long
   * boundary will be zeroed or filled as well. Consider to use
   * bitmap_clear() or bitmap_set() to make explicit zeroing or filling
   * respectively.

   */

  /**
   * DOC: bitmap bitops
   *
   * Also the following operations in asm/bitops.h apply to bitmaps.::
   *
   *  set_bit(bit, addr)                  *addr |= bit
   *  clear_bit(bit, addr)                *addr &= ~bit
   *  change_bit(bit, addr)               *addr ^= bit
   *  test_bit(bit, addr)                 Is bit set in *addr?
   *  test_and_set_bit(bit, addr)         Set bit and return old value
   *  test_and_clear_bit(bit, addr)       Clear bit and return old value
   *  test_and_change_bit(bit, addr)      Change bit and return old value
   *  find_first_zero_bit(addr, nbits)    Position first zero bit in *addr
   *  find_first_bit(addr, nbits)         Position first set bit in *addr

   *  find_next_zero_bit(addr, nbits, bit)
   *                                      Position next zero bit in *addr >= bit

   *  find_next_bit(addr, nbits, bit)     Position next set bit in *addr >= bit

   *  find_next_and_bit(addr1, addr2, nbits, bit)
   *                                      Same as find_next_bit, but in
   *                                      (*addr1 & *addr2)

   *

   */

  /**
   * DOC: declare bitmap

   * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used
   * to declare an array named 'name' of just enough unsigned longs to
   * contain all bit positions from 0 to 'bits' - 1.
   */
  
  /*

   * Allocation and deallocation of bitmap.
   * Provided in lib/bitmap.c to avoid circular dependency.
   */
  extern unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags);
  extern unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags);
  extern void bitmap_free(const unsigned long *bitmap);
  
  /*

   * lib/bitmap.c provides these functions:
   */

  extern int __bitmap_empty(const unsigned long *bitmap, unsigned int nbits);

  extern int __bitmap_full(const unsigned long *bitmap, unsigned int nbits);

  extern int __bitmap_equal(const unsigned long *bitmap1,

  			  const unsigned long *bitmap2, unsigned int nbits);

  extern bool __pure __bitmap_or_equal(const unsigned long *src1,
  				     const unsigned long *src2,
  				     const unsigned long *src3,
  				     unsigned int nbits);

  extern void __bitmap_complement(unsigned long *dst, const unsigned long *src,

  			unsigned int nbits);

  extern void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
  				unsigned int shift, unsigned int nbits);

  extern void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
  				unsigned int shift, unsigned int nbits);

  extern void bitmap_cut(unsigned long *dst, const unsigned long *src,
  		       unsigned int first, unsigned int cut,
  		       unsigned int nbits);

  extern int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,

  			const unsigned long *bitmap2, unsigned int nbits);

  extern void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,

  			const unsigned long *bitmap2, unsigned int nbits);

  extern void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,

  			const unsigned long *bitmap2, unsigned int nbits);

  extern int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,

  			const unsigned long *bitmap2, unsigned int nbits);

  extern void __bitmap_replace(unsigned long *dst,
  			const unsigned long *old, const unsigned long *new,
  			const unsigned long *mask, unsigned int nbits);

  extern int __bitmap_intersects(const unsigned long *bitmap1,

  			const unsigned long *bitmap2, unsigned int nbits);

  extern int __bitmap_subset(const unsigned long *bitmap1,

  			const unsigned long *bitmap2, unsigned int nbits);

  extern int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);

  extern void __bitmap_set(unsigned long *map, unsigned int start, int len);
  extern void __bitmap_clear(unsigned long *map, unsigned int start, int len);

  
  extern unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
  						    unsigned long size,
  						    unsigned long start,
  						    unsigned int nr,
  						    unsigned long align_mask,
  						    unsigned long align_offset);
  
  /**
   * bitmap_find_next_zero_area - find a contiguous aligned zero area
   * @map: The address to base the search on
   * @size: The bitmap size in bits
   * @start: The bitnumber to start searching at
   * @nr: The number of zeroed bits we're looking for
   * @align_mask: Alignment mask for zero area
   *
   * The @align_mask should be one less than a power of 2; the effect is that
   * the bit offset of all zero areas this function finds is multiples of that
   * power of 2. A @align_mask of 0 means no alignment is required.
   */
  static inline unsigned long
  bitmap_find_next_zero_area(unsigned long *map,
  			   unsigned long size,
  			   unsigned long start,
  			   unsigned int nr,
  			   unsigned long align_mask)
  {
  	return bitmap_find_next_zero_area_off(map, size, start, nr,
  					      align_mask, 0);
  }

  extern int bitmap_parse(const char *buf, unsigned int buflen,

  			unsigned long *dst, int nbits);
  extern int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,

  			unsigned long *dst, int nbits);

  extern int bitmap_parselist(const char *buf, unsigned long *maskp,
  			int nmaskbits);

  extern int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen,
  			unsigned long *dst, int nbits);

  extern void bitmap_remap(unsigned long *dst, const unsigned long *src,

  		const unsigned long *old, const unsigned long *new, unsigned int nbits);

  extern int bitmap_bitremap(int oldbit,
  		const unsigned long *old, const unsigned long *new, int bits);

  extern void bitmap_onto(unsigned long *dst, const unsigned long *orig,

  		const unsigned long *relmap, unsigned int bits);

  extern void bitmap_fold(unsigned long *dst, const unsigned long *orig,

  		unsigned int sz, unsigned int nbits);

  extern int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order);
  extern void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order);
  extern int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order);

  #ifdef __BIG_ENDIAN

  extern void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits);

  #else
  #define bitmap_copy_le bitmap_copy
  #endif

  extern unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int ord, unsigned int nbits);

  extern int bitmap_print_to_pagebuf(bool list, char *buf,
  				   const unsigned long *maskp, int nmaskbits);

  #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
  #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))

  /*
   * The static inlines below do not handle constant nbits==0 correctly,
   * so make such users (should any ever turn up) call the out-of-line
   * versions.
   */

  #define small_const_nbits(nbits) \

  	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0)

  static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)

  {

  	unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
  	memset(dst, 0, len);

  }

  static inline void bitmap_fill(unsigned long *dst, unsigned int nbits)

  {

  	unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
  	memset(dst, 0xff, len);

  }
  
  static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,

  			unsigned int nbits)

  {

  	unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
  	memcpy(dst, src, len);

  }

  /*
   * Copy bitmap and clear tail bits in last word.
   */
  static inline void bitmap_copy_clear_tail(unsigned long *dst,
  		const unsigned long *src, unsigned int nbits)
  {
  	bitmap_copy(dst, src, nbits);
  	if (nbits % BITS_PER_LONG)
  		dst[nbits / BITS_PER_LONG] &= BITMAP_LAST_WORD_MASK(nbits);
  }
  
  /*
   * On 32-bit systems bitmaps are represented as u32 arrays internally, and
   * therefore conversion is not needed when copying data from/to arrays of u32.
   */
  #if BITS_PER_LONG == 64
  extern void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf,
  							unsigned int nbits);
  extern void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap,
  							unsigned int nbits);
  #else
  #define bitmap_from_arr32(bitmap, buf, nbits)			\
  	bitmap_copy_clear_tail((unsigned long *) (bitmap),	\
  			(const unsigned long *) (buf), (nbits))
  #define bitmap_to_arr32(buf, bitmap, nbits)			\
  	bitmap_copy_clear_tail((unsigned long *) (buf),		\
  			(const unsigned long *) (bitmap), (nbits))
  #endif

  static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,

  			const unsigned long *src2, unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;

  	return __bitmap_and(dst, src1, src2, nbits);

  }
  
  static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,

  			const unsigned long *src2, unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		*dst = *src1 | *src2;
  	else
  		__bitmap_or(dst, src1, src2, nbits);
  }
  
  static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,

  			const unsigned long *src2, unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		*dst = *src1 ^ *src2;
  	else
  		__bitmap_xor(dst, src1, src2, nbits);
  }

  static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,

  			const unsigned long *src2, unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;

  	return __bitmap_andnot(dst, src1, src2, nbits);

  }
  
  static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,

  			unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		*dst = ~(*src);

  	else
  		__bitmap_complement(dst, src, nbits);
  }

  #ifdef __LITTLE_ENDIAN
  #define BITMAP_MEM_ALIGNMENT 8
  #else
  #define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long))
  #endif
  #define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1)

  static inline int bitmap_equal(const unsigned long *src1,

  			const unsigned long *src2, unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));

  	if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
  	    IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))

  		return !memcmp(src1, src2, nbits / 8);

  	return __bitmap_equal(src1, src2, nbits);

  }

  /**

   * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third

   * @src1:	Pointer to bitmap 1
   * @src2:	Pointer to bitmap 2 will be or'ed with bitmap 1
   * @src3:	Pointer to bitmap 3. Compare to the result of *@src1 | *@src2

   * @nbits:	number of bits in each of these bitmaps

   *
   * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise
   */
  static inline bool bitmap_or_equal(const unsigned long *src1,
  				   const unsigned long *src2,
  				   const unsigned long *src3,
  				   unsigned int nbits)
  {
  	if (!small_const_nbits(nbits))
  		return __bitmap_or_equal(src1, src2, src3, nbits);
  
  	return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits));
  }

  static inline int bitmap_intersects(const unsigned long *src1,

  			const unsigned long *src2, unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
  	else
  		return __bitmap_intersects(src1, src2, nbits);
  }
  
  static inline int bitmap_subset(const unsigned long *src1,

  			const unsigned long *src2, unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));
  	else
  		return __bitmap_subset(src1, src2, nbits);
  }

  static inline int bitmap_empty(const unsigned long *src, unsigned nbits)

  {

  	if (small_const_nbits(nbits))

  		return ! (*src & BITMAP_LAST_WORD_MASK(nbits));

  
  	return find_first_bit(src, nbits) == nbits;

  }

  static inline int bitmap_full(const unsigned long *src, unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));

  
  	return find_first_zero_bit(src, nbits) == nbits;

  }

  static __always_inline int bitmap_weight(const unsigned long *src, unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));

  	return __bitmap_weight(src, nbits);
  }

  static __always_inline void bitmap_set(unsigned long *map, unsigned int start,
  		unsigned int nbits)
  {
  	if (__builtin_constant_p(nbits) && nbits == 1)
  		__set_bit(start, map);

  	else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
  		 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
  		 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
  		 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))

  		memset((char *)map + start / 8, 0xff, nbits / 8);

  	else
  		__bitmap_set(map, start, nbits);
  }
  
  static __always_inline void bitmap_clear(unsigned long *map, unsigned int start,
  		unsigned int nbits)
  {
  	if (__builtin_constant_p(nbits) && nbits == 1)
  		__clear_bit(start, map);

  	else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
  		 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
  		 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
  		 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))

  		memset((char *)map + start / 8, 0, nbits / 8);

  	else
  		__bitmap_clear(map, start, nbits);
  }

  static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src,

  				unsigned int shift, unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		*dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift;

  	else

  		__bitmap_shift_right(dst, src, shift, nbits);

  }

  static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src,
  				unsigned int shift, unsigned int nbits)

  {

  	if (small_const_nbits(nbits))

  		*dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits);

  	else

  		__bitmap_shift_left(dst, src, shift, nbits);

  }

  static inline void bitmap_replace(unsigned long *dst,
  				  const unsigned long *old,
  				  const unsigned long *new,
  				  const unsigned long *mask,
  				  unsigned int nbits)
  {
  	if (small_const_nbits(nbits))
  		*dst = (*old & ~(*mask)) | (*new & *mask);
  	else
  		__bitmap_replace(dst, old, new, mask, nbits);
  }

  static inline void bitmap_next_clear_region(unsigned long *bitmap,
  					    unsigned int *rs, unsigned int *re,
  					    unsigned int end)
  {
  	*rs = find_next_zero_bit(bitmap, end, *rs);
  	*re = find_next_bit(bitmap, end, *rs + 1);
  }
  
  static inline void bitmap_next_set_region(unsigned long *bitmap,
  					  unsigned int *rs, unsigned int *re,
  					  unsigned int end)
  {
  	*rs = find_next_bit(bitmap, end, *rs);
  	*re = find_next_zero_bit(bitmap, end, *rs + 1);
  }
  
  /*
   * Bitmap region iterators.  Iterates over the bitmap between [@start, @end).
   * @rs and @re should be integer variables and will be set to start and end
   * index of the current clear or set region.
   */
  #define bitmap_for_each_clear_region(bitmap, rs, re, start, end)	     \
  	for ((rs) = (start),						     \
  	     bitmap_next_clear_region((bitmap), &(rs), &(re), (end));	     \
  	     (rs) < (re);						     \
  	     (rs) = (re) + 1,						     \
  	     bitmap_next_clear_region((bitmap), &(rs), &(re), (end)))
  
  #define bitmap_for_each_set_region(bitmap, rs, re, start, end)		     \
  	for ((rs) = (start),						     \
  	     bitmap_next_set_region((bitmap), &(rs), &(re), (end));	     \
  	     (rs) < (re);						     \
  	     (rs) = (re) + 1,						     \
  	     bitmap_next_set_region((bitmap), &(rs), &(re), (end)))

  /**

   * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.

   * @n: u64 value

   *
   * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit
   * integers in 32-bit environment, and 64-bit integers in 64-bit one.
   *
   * There are four combinations of endianness and length of the word in linux
   * ABIs: LE64, BE64, LE32 and BE32.
   *
   * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in
   * bitmaps and therefore don't require any special handling.
   *
   * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory
   * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the
   * other hand is represented as an array of 32-bit words and the position of
   * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that
   * word.  For example, bit #42 is located at 10th position of 2nd word.
   * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit
   * values in memory as it usually does. But for BE we need to swap hi and lo
   * words manually.
   *
   * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and
   * lo parts of u64.  For LE32 it does nothing, and for BE environment it swaps
   * hi and lo words, as is expected by bitmap.
   */
  #if __BITS_PER_LONG == 64
  #define BITMAP_FROM_U64(n) (n)
  #else
  #define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \
  				((unsigned long) ((u64)(n) >> 32))
  #endif

  /**

   * bitmap_from_u64 - Check and swap words within u64.
   *  @mask: source bitmap
   *  @dst:  destination bitmap
   *

   * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]``

   * to read u64 mask, we will get the wrong word.

   * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits,

   * but we expect the lower 32-bits of u64.
   */
  static inline void bitmap_from_u64(unsigned long *dst, u64 mask)
  {
  	dst[0] = mask & ULONG_MAX;
  
  	if (sizeof(mask) > sizeof(unsigned long))
  		dst[1] = mask >> 32;
  }

  /**
   * bitmap_get_value8 - get an 8-bit value within a memory region
   * @map: address to the bitmap memory region
   * @start: bit offset of the 8-bit value; must be a multiple of 8
   *
   * Returns the 8-bit value located at the @start bit offset within the @src
   * memory region.
   */
  static inline unsigned long bitmap_get_value8(const unsigned long *map,
  					      unsigned long start)
  {
  	const size_t index = BIT_WORD(start);
  	const unsigned long offset = start % BITS_PER_LONG;
  
  	return (map[index] >> offset) & 0xFF;
  }
  
  /**
   * bitmap_set_value8 - set an 8-bit value within a memory region
   * @map: address to the bitmap memory region
   * @value: the 8-bit value; values wider than 8 bits may clobber bitmap
   * @start: bit offset of the 8-bit value; must be a multiple of 8
   */
  static inline void bitmap_set_value8(unsigned long *map, unsigned long value,
  				     unsigned long start)
  {
  	const size_t index = BIT_WORD(start);
  	const unsigned long offset = start % BITS_PER_LONG;
  
  	map[index] &= ~(0xFFUL << offset);
  	map[index] |= value << offset;
  }

  #endif /* __ASSEMBLY__ */
  
  #endif /* __LINUX_BITMAP_H */