xref: /openbmc/linux/arch/arm/lib/copy_from_user.S (revision e23feb16) 
1/*
2 *  linux/arch/arm/lib/copy_from_user.S
3 *
4 *  Author:	Nicolas Pitre
5 *  Created:	Sep 29, 2005
6 *  Copyright:	MontaVista Software, Inc.
7 *
8 *  This program is free software; you can redistribute it and/or modify
9 *  it under the terms of the GNU General Public License version 2 as
10 *  published by the Free Software Foundation.
11 */
12
13#include <linux/linkage.h>
14#include <asm/assembler.h>
15
16/*
17 * Prototype:
18 *
19 *	size_t __copy_from_user(void *to, const void *from, size_t n)
20 *
21 * Purpose:
22 *
23 *	copy a block to kernel memory from user memory
24 *
25 * Params:
26 *
27 *	to = kernel memory
28 *	from = user memory
29 *	n = number of bytes to copy
30 *
31 * Return value:
32 *
33 *	Number of bytes NOT copied.
34 */
35
36#ifndef CONFIG_THUMB2_KERNEL
37#define LDR1W_SHIFT	0
38#else
39#define LDR1W_SHIFT	1
40#endif
41#define STR1W_SHIFT	0
42
43	.macro ldr1w ptr reg abort
44	ldrusr	\reg, \ptr, 4, abort=\abort
45	.endm
46
47	.macro ldr4w ptr reg1 reg2 reg3 reg4 abort
48	ldr1w \ptr, \reg1, \abort
49	ldr1w \ptr, \reg2, \abort
50	ldr1w \ptr, \reg3, \abort
51	ldr1w \ptr, \reg4, \abort
52	.endm
53
54	.macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
55	ldr4w \ptr, \reg1, \reg2, \reg3, \reg4, \abort
56	ldr4w \ptr, \reg5, \reg6, \reg7, \reg8, \abort
57	.endm
58
59	.macro ldr1b ptr reg cond=al abort
60	ldrusr	\reg, \ptr, 1, \cond, abort=\abort
61	.endm
62
63	.macro str1w ptr reg abort
64	W(str) \reg, [\ptr], #4
65	.endm
66
67	.macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
68	stmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
69	.endm
70
71	.macro str1b ptr reg cond=al abort
72	str\cond\()b \reg, [\ptr], #1
73	.endm
74
75	.macro enter reg1 reg2
76	mov	r3, #0
77	stmdb	sp!, {r0, r2, r3, \reg1, \reg2}
78	.endm
79
80	.macro exit reg1 reg2
81	add	sp, sp, #8
82	ldmfd	sp!, {r0, \reg1, \reg2}
83	.endm
84
85	.text
86
87ENTRY(__copy_from_user)
88
89#include "copy_template.S"
90
91ENDPROC(__copy_from_user)
92
93	.pushsection .fixup,"ax"
94	.align 0
95	copy_abort_preamble
96	ldmfd	sp!, {r1, r2}
97	sub	r3, r0, r1
98	rsb	r1, r3, r2
99	str	r1, [sp]
100	bl	__memzero
101	ldr	r0, [sp], #4
102	copy_abort_end
103	.popsection
104
105