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77c93b2f23
This patch implements low-level uaccess libraries. Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn> Acked-by: Arnd Bergmann <arnd@arndb.de>
46 lines
1.0 KiB
ArmAsm
46 lines
1.0 KiB
ArmAsm
/*
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* linux/arch/unicore32/lib/strncpy_from_user.S
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*
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* Code specific to PKUnity SoC and UniCore ISA
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*
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* Copyright (C) 2001-2010 GUAN Xue-tao
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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: sub.a r2, r2, #1
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ldrusr r3, r1, 1, ns
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bfs 2f
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stb.w r3, [r0]+, #1
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cxor.a 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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.pushsection .fixup,"ax"
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.align 0
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9001: mov r3, #0
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stb r3, [r0+], #0 @ null terminate
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mov r0, #-EFAULT
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mov pc, lr
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.popsection
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