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 movq $0x0123456789abcdef,%rdx
43 1:
44 .pushsection runtime_ptr_USER_PTR_MAX,"a"
45 .long 1b - 8 - .
46 .popsection
47 cmp %rax, %rdx
48 sbb %rdx, %rdx
49 or %rdx, %rax
50 .else
51 cmp $TASK_SIZE_MAX-\size+1, %eax
52 jae .Lbad_get_user
53 sbb %edx, %edx /* array_index
54 and %edx, %eax
55 .endif
56 .endm
57
58 .macro UACCESS op src dst
59 1: \op \src,\dst
60 _ASM_EXTABLE_UA(1b, __get_user_handle_
61 .endm
62
63
64 .text
65 SYM_FUNC_START(__get_user_1)
66 check_range size=1
67 ASM_STAC
68 UACCESS movzbl (%_ASM_AX),%edx
69 xor %eax,%eax
70 ASM_CLAC
71 RET
72 SYM_FUNC_END(__get_user_1)
73 EXPORT_SYMBOL(__get_user_1)
74
75 SYM_FUNC_START(__get_user_2)
76 check_range size=2
77 ASM_STAC
78 UACCESS movzwl (%_ASM_AX),%edx
79 xor %eax,%eax
80 ASM_CLAC
81 RET
82 SYM_FUNC_END(__get_user_2)
83 EXPORT_SYMBOL(__get_user_2)
84
85 SYM_FUNC_START(__get_user_4)
86 check_range size=4
87 ASM_STAC
88 UACCESS movl (%_ASM_AX),%edx
89 xor %eax,%eax
90 ASM_CLAC
91 RET
92 SYM_FUNC_END(__get_user_4)
93 EXPORT_SYMBOL(__get_user_4)
94
95 SYM_FUNC_START(__get_user_8)
96 #ifndef CONFIG_X86_64
97 xor %ecx,%ecx
98 #endif
99 check_range size=8
100 ASM_STAC
101 #ifdef CONFIG_X86_64
102 UACCESS movq (%_ASM_AX),%rdx
103 #else
104 UACCESS movl (%_ASM_AX),%edx
105 UACCESS movl 4(%_ASM_AX),%ecx
106 #endif
107 xor %eax,%eax
108 ASM_CLAC
109 RET
110 SYM_FUNC_END(__get_user_8)
111 EXPORT_SYMBOL(__get_user_8)
112
113 /* .. and the same for __get_user, just withou
114 SYM_FUNC_START(__get_user_nocheck_1)
115 ASM_STAC
116 ASM_BARRIER_NOSPEC
117 UACCESS movzbl (%_ASM_AX),%edx
118 xor %eax,%eax
119 ASM_CLAC
120 RET
121 SYM_FUNC_END(__get_user_nocheck_1)
122 EXPORT_SYMBOL(__get_user_nocheck_1)
123
124 SYM_FUNC_START(__get_user_nocheck_2)
125 ASM_STAC
126 ASM_BARRIER_NOSPEC
127 UACCESS movzwl (%_ASM_AX),%edx
128 xor %eax,%eax
129 ASM_CLAC
130 RET
131 SYM_FUNC_END(__get_user_nocheck_2)
132 EXPORT_SYMBOL(__get_user_nocheck_2)
133
134 SYM_FUNC_START(__get_user_nocheck_4)
135 ASM_STAC
136 ASM_BARRIER_NOSPEC
137 UACCESS movl (%_ASM_AX),%edx
138 xor %eax,%eax
139 ASM_CLAC
140 RET
141 SYM_FUNC_END(__get_user_nocheck_4)
142 EXPORT_SYMBOL(__get_user_nocheck_4)
143
144 SYM_FUNC_START(__get_user_nocheck_8)
145 ASM_STAC
146 ASM_BARRIER_NOSPEC
147 #ifdef CONFIG_X86_64
148 UACCESS movq (%_ASM_AX),%rdx
149 #else
150 xor %ecx,%ecx
151 UACCESS movl (%_ASM_AX),%edx
152 UACCESS movl 4(%_ASM_AX),%ecx
153 #endif
154 xor %eax,%eax
155 ASM_CLAC
156 RET
157 SYM_FUNC_END(__get_user_nocheck_8)
158 EXPORT_SYMBOL(__get_user_nocheck_8)
159
160
161 SYM_CODE_START_LOCAL(__get_user_handle_excepti
162 ASM_CLAC
163 .Lbad_get_user:
164 xor %edx,%edx
165 mov $(-EFAULT),%_ASM_AX
166 RET
167 SYM_CODE_END(__get_user_handle_exception)
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