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1965aae3 PA |
1 | #ifndef _ASM_X86_UACCESS_32_H |
2 | #define _ASM_X86_UACCESS_32_H | |
1da177e4 LT |
3 | |
4 | /* | |
5 | * User space memory access functions | |
6 | */ | |
1da177e4 LT |
7 | #include <linux/errno.h> |
8 | #include <linux/thread_info.h> | |
1da177e4 | 9 | #include <linux/string.h> |
14e6d17d | 10 | #include <asm/asm.h> |
1da177e4 LT |
11 | #include <asm/page.h> |
12 | ||
b1fcec7f JP |
13 | unsigned long __must_check __copy_to_user_ll |
14 | (void __user *to, const void *from, unsigned long n); | |
15 | unsigned long __must_check __copy_from_user_ll | |
16 | (void *to, const void __user *from, unsigned long n); | |
17 | unsigned long __must_check __copy_from_user_ll_nozero | |
18 | (void *to, const void __user *from, unsigned long n); | |
19 | unsigned long __must_check __copy_from_user_ll_nocache | |
20 | (void *to, const void __user *from, unsigned long n); | |
21 | unsigned long __must_check __copy_from_user_ll_nocache_nozero | |
22 | (void *to, const void __user *from, unsigned long n); | |
1da177e4 | 23 | |
6d1c4261 AK |
24 | /** |
25 | * __copy_to_user_inatomic: - Copy a block of data into user space, with less checking. | |
26 | * @to: Destination address, in user space. | |
27 | * @from: Source address, in kernel space. | |
28 | * @n: Number of bytes to copy. | |
29 | * | |
30 | * Context: User context only. | |
31 | * | |
32 | * Copy data from kernel space to user space. Caller must check | |
33 | * the specified block with access_ok() before calling this function. | |
34 | * The caller should also make sure he pins the user space address | |
4fe48782 | 35 | * so that we don't result in page fault and sleep. |
6d1c4261 | 36 | * |
1da177e4 LT |
37 | * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault |
38 | * we return the initial request size (1, 2 or 4), as copy_*_user should do. | |
39 | * If a store crosses a page boundary and gets a fault, the x86 will not write | |
40 | * anything, so this is accurate. | |
41 | */ | |
42 | ||
652050ae | 43 | static __always_inline unsigned long __must_check |
1da177e4 LT |
44 | __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n) |
45 | { | |
46 | if (__builtin_constant_p(n)) { | |
47 | unsigned long ret; | |
48 | ||
49 | switch (n) { | |
50 | case 1: | |
b1fcec7f JP |
51 | __put_user_size(*(u8 *)from, (u8 __user *)to, |
52 | 1, ret, 1); | |
1da177e4 LT |
53 | return ret; |
54 | case 2: | |
b1fcec7f JP |
55 | __put_user_size(*(u16 *)from, (u16 __user *)to, |
56 | 2, ret, 2); | |
1da177e4 LT |
57 | return ret; |
58 | case 4: | |
b1fcec7f JP |
59 | __put_user_size(*(u32 *)from, (u32 __user *)to, |
60 | 4, ret, 4); | |
1da177e4 LT |
61 | return ret; |
62 | } | |
63 | } | |
64 | return __copy_to_user_ll(to, from, n); | |
65 | } | |
66 | ||
1da177e4 | 67 | /** |
9c7fff6e RD |
68 | * __copy_to_user: - Copy a block of data into user space, with less checking. |
69 | * @to: Destination address, in user space. | |
70 | * @from: Source address, in kernel space. | |
1da177e4 LT |
71 | * @n: Number of bytes to copy. |
72 | * | |
73 | * Context: User context only. This function may sleep. | |
74 | * | |
9c7fff6e | 75 | * Copy data from kernel space to user space. Caller must check |
1da177e4 LT |
76 | * the specified block with access_ok() before calling this function. |
77 | * | |
78 | * Returns number of bytes that could not be copied. | |
79 | * On success, this will be zero. | |
1da177e4 | 80 | */ |
9c7fff6e RD |
81 | static __always_inline unsigned long __must_check |
82 | __copy_to_user(void __user *to, const void *from, unsigned long n) | |
83 | { | |
3ee1afa3 | 84 | might_fault(); |
c10d38dd | 85 | return __copy_to_user_inatomic(to, from, n); |
9c7fff6e RD |
86 | } |
87 | ||
652050ae | 88 | static __always_inline unsigned long |
1da177e4 LT |
89 | __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) |
90 | { | |
7c12d811 N |
91 | /* Avoid zeroing the tail if the copy fails.. |
92 | * If 'n' is constant and 1, 2, or 4, we do still zero on a failure, | |
93 | * but as the zeroing behaviour is only significant when n is not | |
94 | * constant, that shouldn't be a problem. | |
95 | */ | |
96 | if (__builtin_constant_p(n)) { | |
97 | unsigned long ret; | |
98 | ||
99 | switch (n) { | |
100 | case 1: | |
101 | __get_user_size(*(u8 *)to, from, 1, ret, 1); | |
102 | return ret; | |
103 | case 2: | |
104 | __get_user_size(*(u16 *)to, from, 2, ret, 2); | |
105 | return ret; | |
106 | case 4: | |
107 | __get_user_size(*(u32 *)to, from, 4, ret, 4); | |
108 | return ret; | |
109 | } | |
110 | } | |
111 | return __copy_from_user_ll_nozero(to, from, n); | |
112 | } | |
9c7fff6e RD |
113 | |
114 | /** | |
115 | * __copy_from_user: - Copy a block of data from user space, with less checking. | |
116 | * @to: Destination address, in kernel space. | |
117 | * @from: Source address, in user space. | |
118 | * @n: Number of bytes to copy. | |
119 | * | |
120 | * Context: User context only. This function may sleep. | |
121 | * | |
122 | * Copy data from user space to kernel space. Caller must check | |
123 | * the specified block with access_ok() before calling this function. | |
124 | * | |
125 | * Returns number of bytes that could not be copied. | |
126 | * On success, this will be zero. | |
127 | * | |
128 | * If some data could not be copied, this function will pad the copied | |
129 | * data to the requested size using zero bytes. | |
130 | * | |
131 | * An alternate version - __copy_from_user_inatomic() - may be called from | |
132 | * atomic context and will fail rather than sleep. In this case the | |
133 | * uncopied bytes will *NOT* be padded with zeros. See fs/filemap.h | |
134 | * for explanation of why this is needed. | |
135 | */ | |
7c12d811 N |
136 | static __always_inline unsigned long |
137 | __copy_from_user(void *to, const void __user *from, unsigned long n) | |
138 | { | |
3ee1afa3 | 139 | might_fault(); |
1da177e4 LT |
140 | if (__builtin_constant_p(n)) { |
141 | unsigned long ret; | |
142 | ||
143 | switch (n) { | |
144 | case 1: | |
145 | __get_user_size(*(u8 *)to, from, 1, ret, 1); | |
146 | return ret; | |
147 | case 2: | |
148 | __get_user_size(*(u16 *)to, from, 2, ret, 2); | |
149 | return ret; | |
150 | case 4: | |
151 | __get_user_size(*(u32 *)to, from, 4, ret, 4); | |
152 | return ret; | |
153 | } | |
154 | } | |
155 | return __copy_from_user_ll(to, from, n); | |
156 | } | |
157 | ||
7c12d811 | 158 | static __always_inline unsigned long __copy_from_user_nocache(void *to, |
c22ce143 HY |
159 | const void __user *from, unsigned long n) |
160 | { | |
3ee1afa3 | 161 | might_fault(); |
c22ce143 HY |
162 | if (__builtin_constant_p(n)) { |
163 | unsigned long ret; | |
164 | ||
165 | switch (n) { | |
166 | case 1: | |
167 | __get_user_size(*(u8 *)to, from, 1, ret, 1); | |
168 | return ret; | |
169 | case 2: | |
170 | __get_user_size(*(u16 *)to, from, 2, ret, 2); | |
171 | return ret; | |
172 | case 4: | |
173 | __get_user_size(*(u32 *)to, from, 4, ret, 4); | |
174 | return ret; | |
175 | } | |
176 | } | |
177 | return __copy_from_user_ll_nocache(to, from, n); | |
178 | } | |
179 | ||
652050ae | 180 | static __always_inline unsigned long |
b1fcec7f JP |
181 | __copy_from_user_inatomic_nocache(void *to, const void __user *from, |
182 | unsigned long n) | |
1da177e4 | 183 | { |
7c12d811 | 184 | return __copy_from_user_ll_nocache_nozero(to, from, n); |
c22ce143 HY |
185 | } |
186 | ||
1da177e4 | 187 | unsigned long __must_check copy_to_user(void __user *to, |
b1fcec7f | 188 | const void *from, unsigned long n); |
9f0cf4ad | 189 | unsigned long __must_check _copy_from_user(void *to, |
b1fcec7f JP |
190 | const void __user *from, |
191 | unsigned long n); | |
9f0cf4ad | 192 | |
4a312769 AV |
193 | |
194 | extern void copy_from_user_overflow(void) | |
63312b6a AV |
195 | #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS |
196 | __compiletime_error("copy_from_user() buffer size is not provably correct") | |
197 | #else | |
4a312769 AV |
198 | __compiletime_warning("copy_from_user() buffer size is not provably correct") |
199 | #endif | |
200 | ; | |
201 | ||
9f0cf4ad AV |
202 | static inline unsigned long __must_check copy_from_user(void *to, |
203 | const void __user *from, | |
204 | unsigned long n) | |
205 | { | |
206 | int sz = __compiletime_object_size(to); | |
9f0cf4ad AV |
207 | |
208 | if (likely(sz == -1 || sz >= n)) | |
409d02ef | 209 | n = _copy_from_user(to, from, n); |
9f0cf4ad | 210 | else |
4a312769 AV |
211 | copy_from_user_overflow(); |
212 | ||
409d02ef | 213 | return n; |
9f0cf4ad AV |
214 | } |
215 | ||
1da177e4 LT |
216 | unsigned long __must_check clear_user(void __user *mem, unsigned long len); |
217 | unsigned long __must_check __clear_user(void __user *mem, unsigned long len); | |
218 | ||
1965aae3 | 219 | #endif /* _ASM_X86_UACCESS_32_H */ |