mirror of https://gitee.com/openkylin/linux.git
44 lines
975 B
ArmAsm
44 lines
975 B
ArmAsm
/*
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* linux/arch/arm/lib/strncpy_from_user.S
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*
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* Copyright (C) 1995-2000 Russell King
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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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#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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/*
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* Copy a string from user space to kernel space.
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* r0 = dst, r1 = src, r2 = byte length
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* returns the number of characters copied (strlen of copied string),
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* -EFAULT on exception, or "len" if we fill the whole buffer
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*/
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ENTRY(__strncpy_from_user)
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mov ip, r1
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1: subs r2, r2, #1
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ldrusr r3, r1, 1, pl
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bmi 2f
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strb r3, [r0], #1
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teq r3, #0
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bne 1b
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sub r1, r1, #1 @ take NUL character out of count
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2: sub r0, r1, ip
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mov pc, lr
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ENDPROC(__strncpy_from_user)
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.section .fixup,"ax"
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.align 0
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9001: mov r3, #0
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strb r3, [r0, #0] @ null terminate
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mov r0, #-EFAULT
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mov pc, lr
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.previous
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