mirror of https://gitee.com/openkylin/linux.git
48 lines
1.3 KiB
ArmAsm
48 lines
1.3 KiB
ArmAsm
/*
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* Based on arch/arm/lib/strnlen_user.S
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*
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* Copyright (C) 1995-2000 Russell King
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/errno.h>
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.text
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.align 5
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/* Prototype: unsigned long __strnlen_user(const char *str, long n)
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* Purpose : get length of a string in user memory
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* Params : str - address of string in user memory
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* Returns : length of string *including terminator*
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* or zero on exception, or n if too long
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*/
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ENTRY(__strnlen_user)
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mov x2, x0
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1: subs x1, x1, #1
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b.mi 2f
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USER(9f, ldrb w3, [x0], #1 )
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cbnz w3, 1b
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2: sub x0, x0, x2
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ret
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ENDPROC(__strnlen_user)
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.section .fixup,"ax"
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.align 0
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9: mov x0, #0
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ret
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.previous
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