xref: /openbmc/linux/arch/arm/lib/copy_from_user.S (revision 0da85d1e) 
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#include <asm/unwind.h>
16
17/*
18 * Prototype:
19 *
20 *	size_t __copy_from_user(void *to, const void *from, size_t n)
21 *
22 * Purpose:
23 *
24 *	copy a block to kernel memory from user memory
25 *
26 * Params:
27 *
28 *	to = kernel memory
29 *	from = user memory
30 *	n = number of bytes to copy
31 *
32 * Return value:
33 *
34 *	Number of bytes NOT copied.
35 */
36
37#ifndef CONFIG_THUMB2_KERNEL
38#define LDR1W_SHIFT	0
39#else
40#define LDR1W_SHIFT	1
41#endif
42#define STR1W_SHIFT	0
43
44	.macro ldr1w ptr reg abort
45	ldrusr	\reg, \ptr, 4, abort=\abort
46	.endm
47
48	.macro ldr4w ptr reg1 reg2 reg3 reg4 abort
49	ldr1w \ptr, \reg1, \abort
50	ldr1w \ptr, \reg2, \abort
51	ldr1w \ptr, \reg3, \abort
52	ldr1w \ptr, \reg4, \abort
53	.endm
54
55	.macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
56	ldr4w \ptr, \reg1, \reg2, \reg3, \reg4, \abort
57	ldr4w \ptr, \reg5, \reg6, \reg7, \reg8, \abort
58	.endm
59
60	.macro ldr1b ptr reg cond=al abort
61	ldrusr	\reg, \ptr, 1, \cond, abort=\abort
62	.endm
63
64	.macro str1w ptr reg abort
65	W(str) \reg, [\ptr], #4
66	.endm
67
68	.macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
69	stmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
70	.endm
71
72	.macro str1b ptr reg cond=al abort
73	str\cond\()b \reg, [\ptr], #1
74	.endm
75
76	.macro enter reg1 reg2
77	mov	r3, #0
78	stmdb	sp!, {r0, r2, r3, \reg1, \reg2}
79	.endm
80
81	.macro usave reg1 reg2
82	UNWIND(	.save {r0, r2, r3, \reg1, \reg2}	)
83	.endm
84
85	.macro exit reg1 reg2
86	add	sp, sp, #8
87	ldmfd	sp!, {r0, \reg1, \reg2}
88	.endm
89
90	.text
91
92ENTRY(__copy_from_user)
93
94#include "copy_template.S"
95
96ENDPROC(__copy_from_user)
97
98	.pushsection .fixup,"ax"
99	.align 0
100	copy_abort_preamble
101	ldmfd	sp!, {r1, r2}
102	sub	r3, r0, r1
103	rsb	r1, r3, r2
104	str	r1, [sp]
105	bl	__memzero
106	ldr	r0, [sp], #4
107	copy_abort_end
108	.popsection
109
110