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>
42 lines
966 B
ArmAsm
42 lines
966 B
ArmAsm
/*
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* linux/arch/unicore32/lib/strnlen_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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/* 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 + 1 if too long
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*/
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ENTRY(__strnlen_user)
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mov r2, r0
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1:
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ldrusr r3, r0, 1
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cxor.a r3, #0
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beq 2f
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sub.a r1, r1, #1
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bne 1b
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add r0, r0, #1
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2: sub r0, r0, r2
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mov pc, lr
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ENDPROC(__strnlen_user)
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.pushsection .fixup,"ax"
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.align 0
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9001: mov r0, #0
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mov pc, lr
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.popsection
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