bits.h 1.6 KB

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  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. #ifndef __LINUX_BITS_H
  3. #define __LINUX_BITS_H
  4. #include <linux/const.h>
  5. #include <vdso/bits.h>
  6. #include <uapi/linux/bits.h>
  7. #include <asm/bitsperlong.h>
  8. #define BIT_MASK(nr) (UL(1) << ((nr) % BITS_PER_LONG))
  9. #define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
  10. #define BIT_ULL_MASK(nr) (ULL(1) << ((nr) % BITS_PER_LONG_LONG))
  11. #define BIT_ULL_WORD(nr) ((nr) / BITS_PER_LONG_LONG)
  12. #define BITS_PER_BYTE 8
  13. /*
  14. * Create a contiguous bitmask starting at bit position @l and ending at
  15. * position @h. For example
  16. * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  17. */
  18. #if !defined(__ASSEMBLY__)
  19. #include <linux/build_bug.h>
  20. #define GENMASK_INPUT_CHECK(h, l) \
  21. (BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
  22. __is_constexpr((l) > (h)), (l) > (h), 0)))
  23. #else
  24. /*
  25. * BUILD_BUG_ON_ZERO is not available in h files included from asm files,
  26. * disable the input check if that is the case.
  27. */
  28. #define GENMASK_INPUT_CHECK(h, l) 0
  29. #endif
  30. #define GENMASK(h, l) \
  31. (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
  32. #define GENMASK_ULL(h, l) \
  33. (GENMASK_INPUT_CHECK(h, l) + __GENMASK_ULL(h, l))
  34. #if !defined(__ASSEMBLY__)
  35. /*
  36. * Missing asm support
  37. *
  38. * __GENMASK_U128() depends on _BIT128() which would not work
  39. * in the asm code, as it shifts an 'unsigned __init128' data
  40. * type instead of direct representation of 128 bit constants
  41. * such as long and unsigned long. The fundamental problem is
  42. * that a 128 bit constant will get silently truncated by the
  43. * gcc compiler.
  44. */
  45. #define GENMASK_U128(h, l) \
  46. (GENMASK_INPUT_CHECK(h, l) + __GENMASK_U128(h, l))
  47. #endif
  48. #endif /* __LINUX_BITS_H */