Add GENMASK_U32(), GENMASK_U16() and GENMASK_U8() macros to create masks for fixed-width types and also the corresponding BIT_U32(), BIT_U16() and BIT_U8(). All of those depend on a new "U" suffix added to the integer constant. Due to naming clashes it's better to call the macro U32. Since C doesn't have a proper suffix for short and char types, the U16 and U18 variants just use U32 with one additional check in the BIT_* macros to make sure the compiler gives an error when the those types overflow. The BIT_U16() and BIT_U8() need the help of GENMASK_INPUT_CHECK(), as otherwise they would allow an invalid bit to be passed. Hence implement them in include/linux/bits.h rather than together with the other BIT* variants. The following test file is is used to test this: $ cat mask.c #include <linux/types.h> #include <linux/bits.h> static const u32 a = GENMASK_U32(31, 0); static const u16 b = GENMASK_U16(15, 0); static const u8 c = GENMASK_U8(7, 0); static const u32 x = BIT_U32(31); static const u16 y = BIT_U16(15); static const u8 z = BIT_U8(7); #if FAIL static const u32 a2 = GENMASK_U32(32, 0); static const u16 b2 = GENMASK_U16(16, 0); static const u8 c2 = GENMASK_U8(8, 0); static const u32 x2 = BIT_U32(32); static const u16 y2 = BIT_U16(16); static const u8 z2 = BIT_U8(8); #endif Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx> --- include/linux/bits.h | 22 ++++++++++++++++++++++ include/uapi/linux/const.h | 2 ++ include/vdso/const.h | 1 + 3 files changed, 25 insertions(+) diff --git a/include/linux/bits.h b/include/linux/bits.h index 7c0cf5031abe..ff4786c99b8c 100644 --- a/include/linux/bits.h +++ b/include/linux/bits.h @@ -42,4 +42,26 @@ #define GENMASK_ULL(h, l) \ (GENMASK_INPUT_CHECK(h, l) + __GENMASK_ULL(h, l)) +#define __GENMASK_U32(h, l) \ + (((~U32(0)) - (U32(1) << (l)) + 1) & \ + (~U32(0) >> (32 - 1 - (h)))) +#define GENMASK_U32(h, l) \ + (GENMASK_INPUT_CHECK(h, l) + __GENMASK_U32(h, l)) + +#define __GENMASK_U16(h, l) \ + ((U32(0xffff) - (U32(1) << (l)) + 1) & \ + (U32(0xffff) >> (16 - 1 - (h)))) +#define GENMASK_U16(h, l) \ + (GENMASK_INPUT_CHECK(h, l) + __GENMASK_U16(h, l)) + +#define __GENMASK_U8(h, l) \ + (((U32(0xff)) - (U32(1) << (l)) + 1) & \ + (U32(0xff) >> (8 - 1 - (h)))) +#define GENMASK_U8(h, l) \ + (GENMASK_INPUT_CHECK(h, l) + __GENMASK_U8(h, l)) + +#define BIT_U32(nr) _BITU32(nr) +#define BIT_U16(nr) (GENMASK_INPUT_CHECK(16 - 1, nr) + (U32(1) << (nr))) +#define BIT_U8(nr) (GENMASK_INPUT_CHECK(32 - 1, nr) + (U32(1) << (nr))) + #endif /* __LINUX_BITS_H */ diff --git a/include/uapi/linux/const.h b/include/uapi/linux/const.h index a429381e7ca5..3a4e152520f4 100644 --- a/include/uapi/linux/const.h +++ b/include/uapi/linux/const.h @@ -22,9 +22,11 @@ #define _AT(T,X) ((T)(X)) #endif +#define _U32(x) (_AC(x, U)) #define _UL(x) (_AC(x, UL)) #define _ULL(x) (_AC(x, ULL)) +#define _BITU32(x) (_U32(1) << (x)) #define _BITUL(x) (_UL(1) << (x)) #define _BITULL(x) (_ULL(1) << (x)) diff --git a/include/vdso/const.h b/include/vdso/const.h index 94b385ad438d..417384a9795b 100644 --- a/include/vdso/const.h +++ b/include/vdso/const.h @@ -4,6 +4,7 @@ #include <uapi/linux/const.h> +#define U32(x) (_U32(x)) #define UL(x) (_UL(x)) #define ULL(x) (_ULL(x)) -- 2.40.1
