diff options
| author | Adrian Hunter <adrian.hunter@intel.com> | 2024-03-25 08:40:09 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-04-08 15:03:07 +0200 |
| commit | 1beb35ec615f676d49d68b6dc23c7418ba8ff145 (patch) | |
| tree | a2ae41ba06edddd74a629dd071340eed60461ae5 | |
| parent | 5e5e51422cd189bc1b627f619f0f99324e6e4de9 (diff) | |
vdso, math64: Provide mul_u64_u32_add_u64_shr()
Provide mul_u64_u32_add_u64_shr() which is a calculation that will be used
by timekeeping and VDSO.
Place #include <vdso/math64.h> after #include <asm/div64.h> to allow
architecture-specific overrides, at least for the kernel.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240325064023.2997-6-adrian.hunter@intel.com
| -rw-r--r-- | include/linux/math64.h | 2 | ||||
| -rw-r--r-- | include/vdso/math64.h | 38 |
2 files changed, 39 insertions, 1 deletions
diff --git a/include/linux/math64.h b/include/linux/math64.h index fd13622b2056..d34def7f9a8c 100644 --- a/include/linux/math64.h +++ b/include/linux/math64.h @@ -4,8 +4,8 @@ #include <linux/types.h> #include <linux/math.h> -#include <vdso/math64.h> #include <asm/div64.h> +#include <vdso/math64.h> #if BITS_PER_LONG == 64 diff --git a/include/vdso/math64.h b/include/vdso/math64.h index 7da703ee5561..22ae212f8b28 100644 --- a/include/vdso/math64.h +++ b/include/vdso/math64.h @@ -21,4 +21,42 @@ __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder) return ret; } +#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) + +#ifndef mul_u64_u32_add_u64_shr +static __always_inline u64 mul_u64_u32_add_u64_shr(u64 a, u32 mul, u64 b, unsigned int shift) +{ + return (u64)((((unsigned __int128)a * mul) + b) >> shift); +} +#endif /* mul_u64_u32_add_u64_shr */ + +#else + +#ifndef mul_u64_u32_add_u64_shr +#ifndef mul_u32_u32 +static inline u64 mul_u32_u32(u32 a, u32 b) +{ + return (u64)a * b; +} +#define mul_u32_u32 mul_u32_u32 +#endif +static __always_inline u64 mul_u64_u32_add_u64_shr(u64 a, u32 mul, u64 b, unsigned int shift) +{ + u32 ah = a >> 32, al = a; + bool ovf; + u64 ret; + + ovf = __builtin_add_overflow(mul_u32_u32(al, mul), b, &ret); + ret >>= shift; + if (ovf && shift) + ret += 1ULL << (64 - shift); + if (ah) + ret += mul_u32_u32(ah, mul) << (32 - shift); + + return ret; +} +#endif /* mul_u64_u32_add_u64_shr */ + +#endif + #endif /* __VDSO_MATH64_H */ |