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
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
/* SPDX-License-Identifier: GPL-2.0 */
/*
* __get_user functions.
*
* (C) Copyright 1998 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.
*/
/*
* __get_user_X
*
* Inputs: %[r|e]ax contains the address.
*
* Outputs: %[r|e]ax is error code (0 or -EFAULT)
* %[r|e]dx contains zero-extended value
* %ecx contains the high half for 32-bit __get_user_8
*
*
* These functions should not modify any other registers,
* as they get called from within inline assembly.
*/
#include <linux/export.h>
#include <linux/linkage.h>
#include <asm/page_types.h>
#include <asm/errno.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/asm.h>
#include <asm/smap.h>
#define ASM_BARRIER_NOSPEC ALTERNATIVE "", "lfence", X86_FEATURE_LFENCE_RDTSC
.macro check_range size:req
.if IS_ENABLED(CONFIG_X86_64)
mov %rax, %rdx
sar $63, %rdx
or %rdx, %rax
.else
cmp $TASK_SIZE_MAX-\size+1, %eax
jae .Lbad_get_user
sbb %edx, %edx /* array_index_mask_nospec() */
and %edx, %eax
.endif
.endm
.text
SYM_FUNC_START(__get_user_1)
check_range size=1
ASM_STAC
1: movzbl (%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
RET
SYM_FUNC_END(__get_user_1)
EXPORT_SYMBOL(__get_user_1)
SYM_FUNC_START(__get_user_2)
check_range size=2
ASM_STAC
2: movzwl (%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
RET
SYM_FUNC_END(__get_user_2)
EXPORT_SYMBOL(__get_user_2)
SYM_FUNC_START(__get_user_4)
check_range size=4
ASM_STAC
3: movl (%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
RET
SYM_FUNC_END(__get_user_4)
EXPORT_SYMBOL(__get_user_4)
SYM_FUNC_START(__get_user_8)
check_range size=8
ASM_STAC
#ifdef CONFIG_X86_64
4: movq (%_ASM_AX),%rdx
#else
4: movl (%_ASM_AX),%edx
5: movl 4(%_ASM_AX),%ecx
#endif
xor %eax,%eax
ASM_CLAC
RET
SYM_FUNC_END(__get_user_8)
EXPORT_SYMBOL(__get_user_8)
/* .. and the same for __get_user, just without the range checks */
SYM_FUNC_START(__get_user_nocheck_1)
ASM_STAC
ASM_BARRIER_NOSPEC
6: movzbl (%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
RET
SYM_FUNC_END(__get_user_nocheck_1)
EXPORT_SYMBOL(__get_user_nocheck_1)
SYM_FUNC_START(__get_user_nocheck_2)
ASM_STAC
ASM_BARRIER_NOSPEC
7: movzwl (%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
RET
SYM_FUNC_END(__get_user_nocheck_2)
EXPORT_SYMBOL(__get_user_nocheck_2)
SYM_FUNC_START(__get_user_nocheck_4)
ASM_STAC
ASM_BARRIER_NOSPEC
8: movl (%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
RET
SYM_FUNC_END(__get_user_nocheck_4)
EXPORT_SYMBOL(__get_user_nocheck_4)
SYM_FUNC_START(__get_user_nocheck_8)
ASM_STAC
ASM_BARRIER_NOSPEC
#ifdef CONFIG_X86_64
9: movq (%_ASM_AX),%rdx
#else
9: movl (%_ASM_AX),%edx
10: movl 4(%_ASM_AX),%ecx
#endif
xor %eax,%eax
ASM_CLAC
RET
SYM_FUNC_END(__get_user_nocheck_8)
EXPORT_SYMBOL(__get_user_nocheck_8)
SYM_CODE_START_LOCAL(__get_user_handle_exception)
ASM_CLAC
.Lbad_get_user:
xor %edx,%edx
mov $(-EFAULT),%_ASM_AX
RET
SYM_CODE_END(__get_user_handle_exception)
#ifdef CONFIG_X86_32
SYM_CODE_START_LOCAL(__get_user_8_handle_exception)
ASM_CLAC
bad_get_user_8:
xor %edx,%edx
xor %ecx,%ecx
mov $(-EFAULT),%_ASM_AX
RET
SYM_CODE_END(__get_user_8_handle_exception)
#endif
/* get_user */
_ASM_EXTABLE_UA(1b, __get_user_handle_exception)
_ASM_EXTABLE_UA(2b, __get_user_handle_exception)
_ASM_EXTABLE_UA(3b, __get_user_handle_exception)
#ifdef CONFIG_X86_64
_ASM_EXTABLE_UA(4b, __get_user_handle_exception)
#else
_ASM_EXTABLE_UA(4b, __get_user_8_handle_exception)
_ASM_EXTABLE_UA(5b, __get_user_8_handle_exception)
#endif
/* __get_user */
_ASM_EXTABLE_UA(6b, __get_user_handle_exception)
_ASM_EXTABLE_UA(7b, __get_user_handle_exception)
_ASM_EXTABLE_UA(8b, __get_user_handle_exception)
#ifdef CONFIG_X86_64
_ASM_EXTABLE_UA(9b, __get_user_handle_exception)
#else
_ASM_EXTABLE_UA(9b, __get_user_8_handle_exception)
_ASM_EXTABLE_UA(10b, __get_user_8_handle_exception)
#endif
|
