linux/arch/arm64/lib/copy_from_user.S
Feng Kan 404268828c arm64: copy_to-from-in_user optimization using copy template
This patch optimize copy_to-from-in_user for arm 64bit architecture. The
copy template is used as template file for all the copy*.S files. Minor
change was made to it to accommodate the copy to/from/in user files.

Signed-off-by: Feng Kan <fkan@apm.com>
Signed-off-by: Balamurugan Shanmugam <bshanmugam@apm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-07 11:34:44 +01:00

90 lines
2.0 KiB
ArmAsm

/*
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/linkage.h>
#include <asm/alternative.h>
#include <asm/assembler.h>
#include <asm/cache.h>
#include <asm/cpufeature.h>
#include <asm/sysreg.h>
/*
* Copy from user space to a kernel buffer (alignment handled by the hardware)
*
* Parameters:
* x0 - to
* x1 - from
* x2 - n
* Returns:
* x0 - bytes not copied
*/
.macro ldrb1 ptr, regB, val
USER(9998f, ldrb \ptr, [\regB], \val)
.endm
.macro strb1 ptr, regB, val
strb \ptr, [\regB], \val
.endm
.macro ldrh1 ptr, regB, val
USER(9998f, ldrh \ptr, [\regB], \val)
.endm
.macro strh1 ptr, regB, val
strh \ptr, [\regB], \val
.endm
.macro ldr1 ptr, regB, val
USER(9998f, ldr \ptr, [\regB], \val)
.endm
.macro str1 ptr, regB, val
str \ptr, [\regB], \val
.endm
.macro ldp1 ptr, regB, regC, val
USER(9998f, ldp \ptr, \regB, [\regC], \val)
.endm
.macro stp1 ptr, regB, regC, val
stp \ptr, \regB, [\regC], \val
.endm
end .req x5
ENTRY(__copy_from_user)
ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_HAS_PAN, \
CONFIG_ARM64_PAN)
add end, x0, x2
#include "copy_template.S"
ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_HAS_PAN, \
CONFIG_ARM64_PAN)
mov x0, #0 // Nothing to copy
ret
ENDPROC(__copy_from_user)
.section .fixup,"ax"
.align 2
9998:
sub x0, end, dst
9999:
strb wzr, [dst], #1 // zero remaining buffer space
cmp dst, end
b.lo 9999b
ret
.previous