1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * __get_user functions.
4 *
5 * (C) Copyright 1998 Linus Torvalds
6 * (C) Copyright 2005 Andi Kleen
7 * (C) Copyright 2008 Glauber Costa
8 *
9 * These functions have a non-standard call in
10 * to make them more efficient, especially as
11 * return an error value in addition to the "r
12 * return value.
13 */
14
15 /*
16 * __get_user_X
17 *
18 * Inputs: %[r|e]ax contains the address.
19 *
20 * Outputs: %[r|e]ax is error code (0 or -
21 * %[r|e]dx contains zero-extende
22 * %ecx contains the high half fo
23 *
24 *
25 * These functions should not modify any other
26 * as they get called from within inline assem
27 */
28
29 #include <linux/export.h>
30 #include <linux/linkage.h>
31 #include <asm/page_types.h>
32 #include <asm/errno.h>
33 #include <asm/asm-offsets.h>
34 #include <asm/thread_info.h>
35 #include <asm/asm.h>
36 #include <asm/smap.h>
37
38 #define ASM_BARRIER_NOSPEC ALTERNATIVE "", "lf
39
40 .macro check_range size:req
41 .if IS_ENABLED(CONFIG_X86_64)
42 mov %rax, %rdx
43 sar $63, %rdx
44 or %rdx, %rax
45 .else
46 cmp $TASK_SIZE_MAX-\size+1, %eax
47 jae .Lbad_get_user
48 sbb %edx, %edx /* array_index
49 and %edx, %eax
50 .endif
51 .endm
52
53 .macro UACCESS op src dst
54 1: \op \src,\dst
55 _ASM_EXTABLE_UA(1b, __get_user_handle_
56 .endm
57
58
59 .text
60 SYM_FUNC_START(__get_user_1)
61 check_range size=1
62 ASM_STAC
63 UACCESS movzbl (%_ASM_AX),%edx
64 xor %eax,%eax
65 ASM_CLAC
66 RET
67 SYM_FUNC_END(__get_user_1)
68 EXPORT_SYMBOL(__get_user_1)
69
70 SYM_FUNC_START(__get_user_2)
71 check_range size=2
72 ASM_STAC
73 UACCESS movzwl (%_ASM_AX),%edx
74 xor %eax,%eax
75 ASM_CLAC
76 RET
77 SYM_FUNC_END(__get_user_2)
78 EXPORT_SYMBOL(__get_user_2)
79
80 SYM_FUNC_START(__get_user_4)
81 check_range size=4
82 ASM_STAC
83 UACCESS movl (%_ASM_AX),%edx
84 xor %eax,%eax
85 ASM_CLAC
86 RET
87 SYM_FUNC_END(__get_user_4)
88 EXPORT_SYMBOL(__get_user_4)
89
90 SYM_FUNC_START(__get_user_8)
91 #ifndef CONFIG_X86_64
92 xor %ecx,%ecx
93 #endif
94 check_range size=8
95 ASM_STAC
96 #ifdef CONFIG_X86_64
97 UACCESS movq (%_ASM_AX),%rdx
98 #else
99 UACCESS movl (%_ASM_AX),%edx
100 UACCESS movl 4(%_ASM_AX),%ecx
101 #endif
102 xor %eax,%eax
103 ASM_CLAC
104 RET
105 SYM_FUNC_END(__get_user_8)
106 EXPORT_SYMBOL(__get_user_8)
107
108 /* .. and the same for __get_user, just withou
109 SYM_FUNC_START(__get_user_nocheck_1)
110 ASM_STAC
111 ASM_BARRIER_NOSPEC
112 UACCESS movzbl (%_ASM_AX),%edx
113 xor %eax,%eax
114 ASM_CLAC
115 RET
116 SYM_FUNC_END(__get_user_nocheck_1)
117 EXPORT_SYMBOL(__get_user_nocheck_1)
118
119 SYM_FUNC_START(__get_user_nocheck_2)
120 ASM_STAC
121 ASM_BARRIER_NOSPEC
122 UACCESS movzwl (%_ASM_AX),%edx
123 xor %eax,%eax
124 ASM_CLAC
125 RET
126 SYM_FUNC_END(__get_user_nocheck_2)
127 EXPORT_SYMBOL(__get_user_nocheck_2)
128
129 SYM_FUNC_START(__get_user_nocheck_4)
130 ASM_STAC
131 ASM_BARRIER_NOSPEC
132 UACCESS movl (%_ASM_AX),%edx
133 xor %eax,%eax
134 ASM_CLAC
135 RET
136 SYM_FUNC_END(__get_user_nocheck_4)
137 EXPORT_SYMBOL(__get_user_nocheck_4)
138
139 SYM_FUNC_START(__get_user_nocheck_8)
140 ASM_STAC
141 ASM_BARRIER_NOSPEC
142 #ifdef CONFIG_X86_64
143 UACCESS movq (%_ASM_AX),%rdx
144 #else
145 xor %ecx,%ecx
146 UACCESS movl (%_ASM_AX),%edx
147 UACCESS movl 4(%_ASM_AX),%ecx
148 #endif
149 xor %eax,%eax
150 ASM_CLAC
151 RET
152 SYM_FUNC_END(__get_user_nocheck_8)
153 EXPORT_SYMBOL(__get_user_nocheck_8)
154
155
156 SYM_CODE_START_LOCAL(__get_user_handle_excepti
157 ASM_CLAC
158 .Lbad_get_user:
159 xor %edx,%edx
160 mov $(-EFAULT),%_ASM_AX
161 RET
162 SYM_CODE_END(__get_user_handle_exception)
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