blob: b1631a7dbe750dc4615e8d76f535e48fb2a0c52d [file] [log] [blame]
* 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
* Outputs: r0 is the error code
* r2, r3 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/errno.h>
1: ldrbt r2, [r0]
mov r0, #0
mov pc, lr
2: ldrbt r2, [r0]
3: ldrbt r3, [r0, #1]
2: ldrbt r2, [r0], #1
3: ldrbt r3, [r0]
#ifndef __ARMEB__
orr r2, r2, r3, lsl #8
orr r2, r3, r2, lsl #8
mov r0, #0
mov pc, lr
4: ldrt r2, [r0]
mov r0, #0
mov pc, lr
mov r2, #0
mov r0, #-EFAULT
mov pc, lr
.pushsection __ex_table, "a"
.long 1b, __get_user_bad
.long 2b, __get_user_bad
.long 3b, __get_user_bad
.long 4b, __get_user_bad