summaryrefslogtreecommitdiff
path: root/arch/x86/lib/putuser.S
blob: d2e5c9c396018e7e255ad0cdbfc5d5a1552d6e8c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * __put_user functions.
 *
 * (C) Copyright 2005 Linus Torvalds
 * (C) Copyright 2005 Andi Kleen
 * (C) Copyright 2008 Glauber Costa
 *
 * These functions have a non-standard call interface
 * to make them more efficient, especially as they
 * return an error value in addition to the "real"
 * return value.
 */
#include <linux/linkage.h>
#include <asm/thread_info.h>
#include <asm/errno.h>
#include <asm/asm.h>
#include <asm/smap.h>
#include <asm/export.h>


/*
 * __put_user_X
 *
 * Inputs:	%eax[:%edx] contains the data
 *		%ecx contains the address
 *
 * Outputs:	%eax is error code (0 or -EFAULT)
 *
 * These functions should not modify any other registers,
 * as they get called from within inline assembly.
 */

#define ENTER	mov PER_CPU_VAR(current_task), %_ASM_BX
#define EXIT	ASM_CLAC ;	\
		ret

.text
ENTRY(__put_user_1)
	ENTER
	cmp TASK_addr_limit(%_ASM_BX),%_ASM_CX
	jae bad_put_user
	ASM_STAC
1:	movb %al,(%_ASM_CX)
	xor %eax,%eax
	EXIT
ENDPROC(__put_user_1)
EXPORT_SYMBOL(__put_user_1)

ENTRY(__put_user_2)
	ENTER
	mov TASK_addr_limit(%_ASM_BX),%_ASM_BX
	sub $1,%_ASM_BX
	cmp %_ASM_BX,%_ASM_CX
	jae bad_put_user
	ASM_STAC
2:	movw %ax,(%_ASM_CX)
	xor %eax,%eax
	EXIT
ENDPROC(__put_user_2)
EXPORT_SYMBOL(__put_user_2)

ENTRY(__put_user_4)
	ENTER
	mov TASK_addr_limit(%_ASM_BX),%_ASM_BX
	sub $3,%_ASM_BX
	cmp %_ASM_BX,%_ASM_CX
	jae bad_put_user
	ASM_STAC
3:	movl %eax,(%_ASM_CX)
	xor %eax,%eax
	EXIT
ENDPROC(__put_user_4)
EXPORT_SYMBOL(__put_user_4)

ENTRY(__put_user_8)
	ENTER
	mov TASK_addr_limit(%_ASM_BX),%_ASM_BX
	sub $7,%_ASM_BX
	cmp %_ASM_BX,%_ASM_CX
	jae bad_put_user
	ASM_STAC
4:	mov %_ASM_AX,(%_ASM_CX)
#ifdef CONFIG_X86_32
5:	movl %edx,4(%_ASM_CX)
#endif
	xor %eax,%eax
	EXIT
ENDPROC(__put_user_8)
EXPORT_SYMBOL(__put_user_8)

bad_put_user:
	movl $-EFAULT,%eax
	EXIT
END(bad_put_user)

	_ASM_EXTABLE_UA(1b, bad_put_user)
	_ASM_EXTABLE_UA(2b, bad_put_user)
	_ASM_EXTABLE_UA(3b, bad_put_user)
	_ASM_EXTABLE_UA(4b, bad_put_user)
#ifdef CONFIG_X86_32
	_ASM_EXTABLE_UA(5b, bad_put_user)
#endif