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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 *
Russell King4baa9922008-08-02 10:55:55 +010023 * No other registers must be altered. (see <asm/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024 * 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 */
Catalin Marinas93ed3972008-08-28 11:22:32 +010029#include <linux/linkage.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <asm/errno.h>
Catalin Marinas247055a2010-09-13 16:03:21 +010031#include <asm/domain.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
Catalin Marinas93ed3972008-08-28 11:22:32 +010033ENTRY(__get_user_1)
Catalin Marinas247055a2010-09-13 16:03:21 +0100341: T(ldrb) r2, [r0]
Linus Torvalds1da177e2005-04-16 15:20:36 -070035 mov r0, #0
36 mov pc, lr
Catalin Marinas93ed3972008-08-28 11:22:32 +010037ENDPROC(__get_user_1)
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
Catalin Marinas93ed3972008-08-28 11:22:32 +010039ENTRY(__get_user_2)
Catalin Marinas8b592782009-07-24 12:32:57 +010040#ifdef CONFIG_THUMB2_KERNEL
Catalin Marinas247055a2010-09-13 16:03:21 +0100412: T(ldrb) r2, [r0]
423: T(ldrb) r3, [r0, #1]
Catalin Marinas8b592782009-07-24 12:32:57 +010043#else
Catalin Marinas247055a2010-09-13 16:03:21 +0100442: T(ldrb) r2, [r0], #1
453: T(ldrb) r3, [r0]
Catalin Marinas8b592782009-07-24 12:32:57 +010046#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#ifndef __ARMEB__
48 orr r2, r2, r3, lsl #8
49#else
50 orr r2, r3, r2, lsl #8
51#endif
52 mov r0, #0
53 mov pc, lr
Catalin Marinas93ed3972008-08-28 11:22:32 +010054ENDPROC(__get_user_2)
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
Catalin Marinas93ed3972008-08-28 11:22:32 +010056ENTRY(__get_user_4)
Catalin Marinas247055a2010-09-13 16:03:21 +0100574: T(ldr) r2, [r0]
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 mov r0, #0
59 mov pc, lr
Catalin Marinas93ed3972008-08-28 11:22:32 +010060ENDPROC(__get_user_4)
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
Linus Torvalds1da177e2005-04-16 15:20:36 -070062__get_user_bad:
63 mov r2, #0
64 mov r0, #-EFAULT
65 mov pc, lr
Catalin Marinas93ed3972008-08-28 11:22:32 +010066ENDPROC(__get_user_bad)
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
Russell King42604152010-04-19 10:15:03 +010068.pushsection __ex_table, "a"
Linus Torvalds1da177e2005-04-16 15:20:36 -070069 .long 1b, __get_user_bad
70 .long 2b, __get_user_bad
71 .long 3b, __get_user_bad
72 .long 4b, __get_user_bad
Russell King42604152010-04-19 10:15:03 +010073.popsection