linux_dsm_epyc7002/arch/powerpc/kernel/vdso32/getcpu.S
Christophe Leroy bfc2eae0ad powerpc/vdso32: miscellaneous optimisations
Various optimisations by inverting branches and removing
redundant instructions.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b4e79f963845545bcce1459cd6fcfe46bdde7863.1575273217.git.christophe.leroy@c-s.fr
2020-01-23 21:31:16 +11:00

51 lines
925 B
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
*
* Copyright (C) IBM Corporation, 2012
*
* Author: Anton Blanchard <anton@au.ibm.com>
*/
#include <asm/ppc_asm.h>
#include <asm/vdso.h>
.text
/*
* Exact prototype of getcpu
*
* int __kernel_getcpu(unsigned *cpu, unsigned *node);
*
*/
#if defined(CONFIG_PPC64)
V_FUNCTION_BEGIN(__kernel_getcpu)
.cfi_startproc
mfspr r5,SPRN_SPRG_VDSO_READ
cmpwi cr0,r3,0
cmpwi cr1,r4,0
clrlwi r6,r5,16
rlwinm r7,r5,16,31-15,31-0
beq cr0,1f
stw r6,0(r3)
1: crclr cr0*4+so
li r3,0 /* always success */
beqlr cr1
stw r7,0(r4)
blr
.cfi_endproc
V_FUNCTION_END(__kernel_getcpu)
#elif !defined(CONFIG_SMP)
V_FUNCTION_BEGIN(__kernel_getcpu)
.cfi_startproc
cmpwi cr0, r3, 0
cmpwi cr1, r4, 0
li r5, 0
beq cr0, 1f
stw r5, 0(r3)
1: li r3, 0 /* always success */
crclr cr0*4+so
beqlr cr1
stw r5, 0(r4)
blr
.cfi_endproc
V_FUNCTION_END(__kernel_getcpu)
#endif