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/*
* Based on arch/arm/lib/strncpy_from_user.S
*
* Copyright (C) 1995-2000 Russell King
* 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/assembler.h>
#include <asm/errno.h>
.text
.align 5
/*
* Copy a string from user space to kernel space.
* x0 = dst, x1 = src, x2 = byte length
* returns the number of characters copied (strlen of copied string),
* -EFAULT on exception, or "len" if we fill the whole buffer
*/
ENTRY(__strncpy_from_user)
mov x4, x1
1: subs x2, x2, #1
bmi 2f
USER(9f, ldrb w3, [x1], #1 )
strb w3, [x0], #1
cbnz w3, 1b
sub x1, x1, #1 // take NUL character out of count
2: sub x0, x1, x4
ret
ENDPROC(__strncpy_from_user)
.section .fixup,"ax"
.align 0
9: strb wzr, [x0] // null terminate
mov x0, #-EFAULT
ret
.previous
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