From b874b8358c756f2503c55686af842d99f5b1f312 Mon Sep 17 00:00:00 2001 From: Vincenzo Frascino Date: Fri, 20 Mar 2020 14:53:34 +0000 Subject: linux/math64.h: Extract common header for vDSO The vDSO library should only include the necessary headers required for a userspace library (UAPI and a minimal set of kernel headers). To make this possible it is necessary to isolate from the kernel headers the common parts that are strictly necessary to build the library. Split math64.h into linux and common headers to make the latter suitable for inclusion in the vDSO library. Signed-off-by: Vincenzo Frascino Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200320145351.32292-10-vincenzo.frascino@arm.com --- include/vdso/math64.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) create mode 100644 include/vdso/math64.h (limited to 'include/vdso') diff --git a/include/vdso/math64.h b/include/vdso/math64.h new file mode 100644 index 000000000000..7da703ee5561 --- /dev/null +++ b/include/vdso/math64.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __VDSO_MATH64_H +#define __VDSO_MATH64_H + +static __always_inline u32 +__iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder) +{ + u32 ret = 0; + + while (dividend >= divisor) { + /* The following asm() prevents the compiler from + optimising this loop into a modulo operation. */ + asm("" : "+rm"(dividend)); + + dividend -= divisor; + ret++; + } + + *remainder = dividend; + + return ret; +} + +#endif /* __VDSO_MATH64_H */ -- cgit v1.2.3