LXR linux/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#define BITS_PER_TYPE(type)     (sizeof(type) * BITS_PER_BYTE)
  16
  17/*
  18 * Create a contiguous bitmask starting at bit position @l and ending at
  19 * position @h. For example
  20 * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  21 */
  22#if !defined(__ASSEMBLY__) && \
  23        (!defined(CONFIG_CC_IS_GCC) || CONFIG_GCC_VERSION >= 49000)
  24#include <linux/build_bug.h>
  25#define GENMASK_INPUT_CHECK(h, l) \
  26        (BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
  27                __builtin_constant_p((l) > (h)), (l) > (h), 0)))
  28#else
  29/*
  30 * BUILD_BUG_ON_ZERO is not available in h files included from asm files,
  31 * disable the input check if that is the case.
  32 */
  33#define GENMASK_INPUT_CHECK(h, l) 0
  34#endif
  35
  36#define __GENMASK(h, l) \
  37        (((~UL(0)) - (UL(1) << (l)) + 1) & \
  38         (~UL(0) >> (BITS_PER_LONG - 1 - (h))))
  39#define GENMASK(h, l) \
  40        (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
  41
  42#define __GENMASK_ULL(h, l) \
  43        (((~ULL(0)) - (ULL(1) << (l)) + 1) & \
  44         (~ULL(0) >> (BITS_PER_LONG_LONG - 1 - (h))))
  45#define GENMASK_ULL(h, l) \
  46        (GENMASK_INPUT_CHECK(h, l) + __GENMASK_ULL(h, l))
  47
  48#endif  /* __LINUX_BITS_H */
  49