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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/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
*/
ENTRY(__copy_from_user)
ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_HAS_PAN, \
CONFIG_ARM64_PAN)
add x5, x1, x2 // upper user buffer boundary
subs x2, x2, #16
b.mi 1f
0:
USER(9f, ldp x3, x4, [x1], #16)
subs x2, x2, #16
stp x3, x4, [x0], #16
b.pl 0b
1: adds x2, x2, #8
b.mi 2f
USER(9f, ldr x3, [x1], #8 )
sub x2, x2, #8
str x3, [x0], #8
2: adds x2, x2, #4
b.mi 3f
USER(9f, ldr w3, [x1], #4 )
sub x2, x2, #4
str w3, [x0], #4
3: adds x2, x2, #2
b.mi 4f
USER(9f, ldrh w3, [x1], #2 )
sub x2, x2, #2
strh w3, [x0], #2
4: adds x2, x2, #1
b.mi 5f
USER(9f, ldrb w3, [x1] )
strb w3, [x0]
5: mov x0, #0
ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_HAS_PAN, \
CONFIG_ARM64_PAN)
ret
ENDPROC(__copy_from_user)
.section .fixup,"ax"
.align 2
9: sub x2, x5, x1
mov x3, x2
10: strb wzr, [x0], #1 // zero remaining buffer space
subs x3, x3, #1
b.ne 10b
mov x0, x2 // bytes not copied
ret
.previous
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