tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
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 <asm/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 */
29#include <linux/linkage.h>
30#include <asm/errno.h>
31
32ENTRY(__get_user_1)
331: ldrbt r2, [r0]
34 mov r0, #0
35 mov pc, lr
36ENDPROC(__get_user_1)
37
38ENTRY(__get_user_2)
39#ifdef CONFIG_THUMB2_KERNEL
402: ldrbt r2, [r0]
413: ldrbt r3, [r0, #1]
42#else
432: ldrbt r2, [r0], #1
443: ldrbt r3, [r0]
45#endif
46#ifndef __ARMEB__
47 orr r2, r2, r3, lsl #8
48#else
49 orr r2, r3, r2, lsl #8
50#endif
51 mov r0, #0
52 mov pc, lr
53ENDPROC(__get_user_2)
54
55ENTRY(__get_user_4)
564: ldrt r2, [r0]
57 mov r0, #0
58 mov pc, lr
59ENDPROC(__get_user_4)
60
61__get_user_bad:
62 mov r2, #0
63 mov r0, #-EFAULT
64 mov pc, lr
65ENDPROC(__get_user_bad)
66
67.pushsection __ex_table, "a"
68 .long 1b, __get_user_bad
69 .long 2b, __get_user_bad
70 .long 3b, __get_user_bad
71 .long 4b, __get_user_bad
72.popsection