Commit b874b835 authored by Vincenzo Frascino's avatar Vincenzo Frascino Committed by Thomas Gleixner
Browse files

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: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-10-vincenzo.frascino@arm.com
parent 14ee2ac6

include/linux/math64.h

+1 −19
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#define _LINUX_MATH64_H



#include <linux/types.h>

#include <vdso/math64.h>

#include <asm/div64.h>



#if BITS_PER_LONG == 64
@@ -142,25 +143,6 @@ static inline s64 div_s64(s64 dividend, s32 divisor) 


u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);



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;

}



#ifndef mul_u32_u32

/*

 * Many a GCC version messes this up and generates a 64x64 mult :-(

include/vdso/math64.h

0 → 100644
+24 −0
Original line number Diff line number Diff line 
/* 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 */

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