mirror of https://gitee.com/openkylin/linux.git
48 lines
1.3 KiB
ArmAsm
48 lines
1.3 KiB
ArmAsm
|
/*
|
||
|
|
* Based on arch/arm/lib/strnlen_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
|
||
|
|
|
||
|
|
/* Prototype: unsigned long __strnlen_user(const char *str, long n)
|
||
|
|
* Purpose : get length of a string in user memory
|
||
|
|
* Params : str - address of string in user memory
|
||
|
|
* Returns : length of string *including terminator*
|
||
|
|
* or zero on exception, or n if too long
|
||
|
|
*/
|
||
|
|
ENTRY(__strnlen_user)
|
||
|
|
mov x2, x0
|
||
|
|
1: subs x1, x1, #1
|
||
|
|
b.mi 2f
|
||
|
|
USER(9f, ldrb w3, [x0], #1 )
|
||
|
|
cbnz w3, 1b
|
||
|
|
2: sub x0, x0, x2
|
||
|
|
ret
|
||
|
|
ENDPROC(__strnlen_user)
|
||
|
|
|
||
|
|
.section .fixup,"ax"
|
||
|
|
.align 0
|
||
|
|
9: mov x0, #0
|
||
|
|
ret
|
||
|
|
.previous
|