include/linux/bits.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __LINUX_BITS_H
   3 #define __LINUX_BITS_H
   4
   5 #include <linux/const.h>
   6 #include <vdso/bits.h>
   7 #include <asm/bitsperlong.h>
   8
   9 #define BIT_ULL(nr)             (ULL(1) << (nr))
  10 #define BIT_MASK(nr)            (UL(1) << ((nr) % BITS_PER_LONG))
  11 #define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
  12 #define BIT_ULL_MASK(nr)        (ULL(1) << ((nr) % BITS_PER_LONG_LONG))
  13 #define BIT_ULL_WORD(nr)        ((nr) / BITS_PER_LONG_LONG)
  14 #define BITS_PER_BYTE           8
  15
  16 /*
  17  * Create a contiguous bitmask starting at bit position @l and ending at
  18  * position @h. For example
  19  * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  20  */
  21 #if !defined(__ASSEMBLY__) && \
  22         (!defined(CONFIG_CC_IS_GCC) || CONFIG_GCC_VERSION >= 49000)
  23 #include <linux/build_bug.h>
  24 #define GENMASK_INPUT_CHECK(h, l) \
  25         (BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
  26                 __builtin_constant_p((l) > (h)), (l) > (h), 0)))
  27 #else
  28 /*
  29  * BUILD_BUG_ON_ZERO is not available in h files included from asm files,
  30  * disable the input check if that is the case.
  31  */
  32 #define GENMASK_INPUT_CHECK(h, l) 0
  33 #endif
  34
  35 #define __GENMASK(h, l) \
  36         (((~UL(0)) - (UL(1) << (l)) + 1) & \
  37          (~UL(0) >> (BITS_PER_LONG - 1 - (h))))
  38 #define GENMASK(h, l) \
  39         (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
  40
  41 #define __GENMASK_ULL(h, l) \
  42         (((~ULL(0)) - (ULL(1) << (l)) + 1) & \
  43          (~ULL(0) >> (BITS_PER_LONG_LONG - 1 - (h))))
  44 #define GENMASK_ULL(h, l) \
  45         (GENMASK_INPUT_CHECK(h, l) + __GENMASK_ULL(h, l))
  46
  47 #endif  /* __LINUX_BITS_H */