diff options
Diffstat (limited to 'include/linux/bitfield.h')
-rw-r--r-- | include/linux/bitfield.h | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h index 4bbb5f1c8b5b..c9be1657f03d 100644 --- a/include/linux/bitfield.h +++ b/include/linux/bitfield.h @@ -19,6 +19,9 @@ * * Example: * + * #include <linux/bitfield.h> + * #include <linux/bits.h> + * * #define REG_FIELD_A GENMASK(6, 0) * #define REG_FIELD_B BIT(7) * #define REG_FIELD_C GENMASK(15, 8) @@ -41,6 +44,22 @@ #define __bf_shf(x) (__builtin_ffsll(x) - 1) +#define __scalar_type_to_unsigned_cases(type) \ + unsigned type: (unsigned type)0, \ + signed type: (unsigned type)0 + +#define __unsigned_scalar_typeof(x) typeof( \ + _Generic((x), \ + char: (unsigned char)0, \ + __scalar_type_to_unsigned_cases(char), \ + __scalar_type_to_unsigned_cases(short), \ + __scalar_type_to_unsigned_cases(int), \ + __scalar_type_to_unsigned_cases(long), \ + __scalar_type_to_unsigned_cases(long long), \ + default: (x))) + +#define __bf_cast_unsigned(type, x) ((__unsigned_scalar_typeof(type))(x)) + #define __BF_FIELD_CHECK(_mask, _reg, _val, _pfx) \ ({ \ BUILD_BUG_ON_MSG(!__builtin_constant_p(_mask), \ @@ -49,13 +68,27 @@ BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \ ~((_mask) >> __bf_shf(_mask)) & (_val) : 0, \ _pfx "value too large for the field"); \ - BUILD_BUG_ON_MSG((_mask) > (typeof(_reg))~0ull, \ + BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) > \ + __bf_cast_unsigned(_reg, ~0ull), \ _pfx "type of reg too small for mask"); \ __BUILD_BUG_ON_NOT_POWER_OF_2((_mask) + \ (1ULL << __bf_shf(_mask))); \ }) /** + * FIELD_MAX() - produce the maximum value representable by a field + * @_mask: shifted mask defining the field's length and position + * + * FIELD_MAX() returns the maximum value that can be held in the field + * specified by @_mask. + */ +#define FIELD_MAX(_mask) \ + ({ \ + __BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_MAX: "); \ + (typeof(_mask))((_mask) >> __bf_shf(_mask)); \ + }) + +/** * FIELD_FIT() - check if value fits in the field * @_mask: shifted mask defining the field's length and position * @_val: value to test against the field @@ -64,7 +97,7 @@ */ #define FIELD_FIT(_mask, _val) \ ({ \ - __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_FIT: "); \ + __BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_FIT: "); \ !((((typeof(_mask))_val) << __bf_shf(_mask)) & ~(_mask)); \ }) @@ -110,6 +143,7 @@ static __always_inline u64 field_mask(u64 field) { return field / field_multiplier(field); } +#define field_max(field) ((typeof(field))field_mask(field)) #define ____MAKE_OP(type,base,to,from) \ static __always_inline __##type type##_encode_bits(base v, base field) \ { \ |