linux/arch/arm64/lib/copy_to_user.S

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/*
* 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 to user space from 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
ldrb \ptr, [\regB], \val
.endm
.macro strb1 ptr, regB, val
USER(9998f, strb \ptr, [\regB], \val)
.endm
.macro ldrh1 ptr, regB, val
ldrh \ptr, [\regB], \val
.endm
.macro strh1 ptr, regB, val
USER(9998f, strh \ptr, [\regB], \val)
.endm
.macro ldr1 ptr, regB, val
ldr \ptr, [\regB], \val
.endm
.macro str1 ptr, regB, val
USER(9998f, str \ptr, [\regB], \val)
.endm
.macro ldp1 ptr, regB, regC, val
ldp \ptr, \regB, [\regC], \val
.endm
.macro stp1 ptr, regB, regC, val
USER(9998f, stp \ptr, \regB, [\regC], \val)
.endm
end .req x5
ENTRY(__copy_to_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
ret
ENDPROC(__copy_to_user)
.section .fixup,"ax"
.align 2
9998: sub x0, end, dst // bytes not copied
ret
.previous