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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/arch/arm/lib/getuser.S
3 *
4 * Copyright (C) 2001 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Idea from x86 version, (C) Copyright 1998 Linus Torvalds
11 *
12 * These functions have a non-standard call interface to make them more
13 * efficient, especially as they return an error value in addition to
14 * the "real" return value.
15 *
16 * __get_user_X
17 *
18 * Inputs: r0 contains the address
19 * Outputs: r0 is the error code
20 * r2, r3 contains the zero-extended value
21 * lr corrupted
22 *
23 * No other registers must be altered. (see include/asm-arm/uaccess.h
24 * for specific ASM register usage).
25 *
26 * Note that ADDR_LIMIT is either 0 or 0xc0000000.
27 * Note also that it is intended that __get_user_bad is not global.
28 */
Sam Ravnborge6ae7442005-09-09 21:08:59 +020029#include <asm/asm-offsets.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <asm/thread_info.h>
31#include <asm/errno.h>
32
33 .global __get_user_1
34__get_user_1:
351: ldrbt r2, [r0]
36 mov r0, #0
37 mov pc, lr
38
39 .global __get_user_2
40__get_user_2:
412: ldrbt r2, [r0], #1
423: ldrbt r3, [r0]
43#ifndef __ARMEB__
44 orr r2, r2, r3, lsl #8
45#else
46 orr r2, r3, r2, lsl #8
47#endif
48 mov r0, #0
49 mov pc, lr
50
51 .global __get_user_4
52__get_user_4:
534: ldrt r2, [r0]
54 mov r0, #0
55 mov pc, lr
56
Linus Torvalds1da177e2005-04-16 15:20:36 -070057__get_user_bad:
58 mov r2, #0
59 mov r0, #-EFAULT
60 mov pc, lr
61
62.section __ex_table, "a"
63 .long 1b, __get_user_bad
64 .long 2b, __get_user_bad
65 .long 3b, __get_user_bad
66 .long 4b, __get_user_bad
Linus Torvalds1da177e2005-04-16 15:20:36 -070067.previous