getuser.S
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/*
* linux/arch/arm/lib/getuser.S
*
* Copyright (C) 2001 Russell King
*
* 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.
*
* Idea from x86 version, (C) Copyright 1998 Linus Torvalds
*
* These functions have a non-standard call interface to make them more
* efficient, especially as they return an error value in addition to
* the "real" return value.
*
* __get_user_X
*
* Inputs: r0 contains the address
* r1 contains the address limit, which must be preserved
* Outputs: r0 is the error code
* r2 contains the zero-extended value
* lr corrupted
*
* No other registers must be altered. (see <asm/uaccess.h>
* for specific ASM register usage).
*
* Note that ADDR_LIMIT is either 0 or 0xc0000000.
* Note also that it is intended that __get_user_bad is not global.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/errno.h>
#include <asm/domain.h>
ENTRY(__get_user_1)
check_uaccess r0, 1, r1, r2, __get_user_bad
1: TUSER(ldrb) r2, [r0]
mov r0, #0
mov pc, lr
ENDPROC(__get_user_1)
ENTRY(__get_user_2)
check_uaccess r0, 2, r1, r2, __get_user_bad
#ifdef CONFIG_CPU_USE_DOMAINS
rb .req ip
2: ldrbt r2, [r0], #1
3: ldrbt rb, [r0], #0
#else
rb .req r0
2: ldrb r2, [r0]
3: ldrb rb, [r0, #1]
#endif
#ifndef __ARMEB__
orr r2, r2, rb, lsl #8
#else
orr r2, rb, r2, lsl #8
#endif
mov r0, #0
mov pc, lr
ENDPROC(__get_user_2)
ENTRY(__get_user_4)
check_uaccess r0, 4, r1, r2, __get_user_bad
4: TUSER(ldr) r2, [r0]
mov r0, #0
mov pc, lr
ENDPROC(__get_user_4)
__get_user_bad:
mov r2, #0
mov r0, #-EFAULT
mov pc, lr
ENDPROC(__get_user_bad)
.pushsection __ex_table, "a"
.long 1b, __get_user_bad
.long 2b, __get_user_bad
.long 3b, __get_user_bad
.long 4b, __get_user_bad
.popsection