diff options
| -rw-r--r-- | include/linux/bits.h | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/include/linux/bits.h b/include/linux/bits.h index 9718c5ae5fc3..7ad056219115 100644 --- a/include/linux/bits.h +++ b/include/linux/bits.h @@ -24,7 +24,7 @@ /* * Missing asm support * - * GENMASK_U*() depend on BITS_PER_TYPE() which relies on sizeof(), + * GENMASK_U*() and BIT_U*() depend on BITS_PER_TYPE() which relies on sizeof(), * something not available in asm. Nevertheless, fixed width integers is a C * concept. Assembly code can rely on the long and long long versions instead. */ @@ -55,6 +55,24 @@ #define GENMASK_U32(h, l) GENMASK_TYPE(u32, h, l) #define GENMASK_U64(h, l) GENMASK_TYPE(u64, h, l) +/* + * Fixed-type variants of BIT(), with additional checks like GENMASK_TYPE(). The + * following examples generate compiler warnings due to -Wshift-count-overflow: + * + * - BIT_U8(8) + * - BIT_U32(-1) + * - BIT_U32(40) + */ +#define BIT_INPUT_CHECK(type, nr) \ + BUILD_BUG_ON_ZERO(const_true((nr) >= BITS_PER_TYPE(type))) + +#define BIT_TYPE(type, nr) ((type)(BIT_INPUT_CHECK(type, nr) + BIT_ULL(nr))) + +#define BIT_U8(nr) BIT_TYPE(u8, nr) +#define BIT_U16(nr) BIT_TYPE(u16, nr) +#define BIT_U32(nr) BIT_TYPE(u32, nr) +#define BIT_U64(nr) BIT_TYPE(u64, nr) + #else /* defined(__ASSEMBLY__) */ /* |