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1da177e4 LT |
1 | #ifndef __i386_UACCESS_H |
2 | #define __i386_UACCESS_H | |
3 | ||
4 | /* | |
5 | * User space memory access functions | |
6 | */ | |
1da177e4 LT |
7 | #include <linux/errno.h> |
8 | #include <linux/thread_info.h> | |
9 | #include <linux/prefetch.h> | |
10 | #include <linux/string.h> | |
14e6d17d | 11 | #include <asm/asm.h> |
1da177e4 LT |
12 | #include <asm/page.h> |
13 | ||
b1fcec7f JP |
14 | unsigned long __must_check __copy_to_user_ll |
15 | (void __user *to, const void *from, unsigned long n); | |
16 | unsigned long __must_check __copy_from_user_ll | |
17 | (void *to, const void __user *from, unsigned long n); | |
18 | unsigned long __must_check __copy_from_user_ll_nozero | |
19 | (void *to, const void __user *from, unsigned long n); | |
20 | unsigned long __must_check __copy_from_user_ll_nocache | |
21 | (void *to, const void __user *from, unsigned long n); | |
22 | unsigned long __must_check __copy_from_user_ll_nocache_nozero | |
23 | (void *to, const void __user *from, unsigned long n); | |
1da177e4 | 24 | |
6d1c4261 AK |
25 | /** |
26 | * __copy_to_user_inatomic: - Copy a block of data into user space, with less checking. | |
27 | * @to: Destination address, in user space. | |
28 | * @from: Source address, in kernel space. | |
29 | * @n: Number of bytes to copy. | |
30 | * | |
31 | * Context: User context only. | |
32 | * | |
33 | * Copy data from kernel space to user space. Caller must check | |
34 | * the specified block with access_ok() before calling this function. | |
35 | * The caller should also make sure he pins the user space address | |
36 | * so that the we don't result in page fault and sleep. | |
37 | * | |
1da177e4 LT |
38 | * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault |
39 | * we return the initial request size (1, 2 or 4), as copy_*_user should do. | |
40 | * If a store crosses a page boundary and gets a fault, the x86 will not write | |
41 | * anything, so this is accurate. | |
42 | */ | |
43 | ||
652050ae | 44 | static __always_inline unsigned long __must_check |
1da177e4 LT |
45 | __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n) |
46 | { | |
47 | if (__builtin_constant_p(n)) { | |
48 | unsigned long ret; | |
49 | ||
50 | switch (n) { | |
51 | case 1: | |
b1fcec7f JP |
52 | __put_user_size(*(u8 *)from, (u8 __user *)to, |
53 | 1, ret, 1); | |
1da177e4 LT |
54 | return ret; |
55 | case 2: | |
b1fcec7f JP |
56 | __put_user_size(*(u16 *)from, (u16 __user *)to, |
57 | 2, ret, 2); | |
1da177e4 LT |
58 | return ret; |
59 | case 4: | |
b1fcec7f JP |
60 | __put_user_size(*(u32 *)from, (u32 __user *)to, |
61 | 4, ret, 4); | |
1da177e4 LT |
62 | return ret; |
63 | } | |
64 | } | |
65 | return __copy_to_user_ll(to, from, n); | |
66 | } | |
67 | ||
1da177e4 | 68 | /** |
9c7fff6e RD |
69 | * __copy_to_user: - Copy a block of data into user space, with less checking. |
70 | * @to: Destination address, in user space. | |
71 | * @from: Source address, in kernel space. | |
1da177e4 LT |
72 | * @n: Number of bytes to copy. |
73 | * | |
74 | * Context: User context only. This function may sleep. | |
75 | * | |
9c7fff6e | 76 | * Copy data from kernel space to user space. Caller must check |
1da177e4 LT |
77 | * the specified block with access_ok() before calling this function. |
78 | * | |
79 | * Returns number of bytes that could not be copied. | |
80 | * On success, this will be zero. | |
1da177e4 | 81 | */ |
9c7fff6e RD |
82 | static __always_inline unsigned long __must_check |
83 | __copy_to_user(void __user *to, const void *from, unsigned long n) | |
84 | { | |
85 | might_sleep(); | |
86 | return __copy_to_user_inatomic(to, from, n); | |
87 | } | |
88 | ||
652050ae | 89 | static __always_inline unsigned long |
1da177e4 LT |
90 | __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) |
91 | { | |
7c12d811 N |
92 | /* Avoid zeroing the tail if the copy fails.. |
93 | * If 'n' is constant and 1, 2, or 4, we do still zero on a failure, | |
94 | * but as the zeroing behaviour is only significant when n is not | |
95 | * constant, that shouldn't be a problem. | |
96 | */ | |
97 | if (__builtin_constant_p(n)) { | |
98 | unsigned long ret; | |
99 | ||
100 | switch (n) { | |
101 | case 1: | |
102 | __get_user_size(*(u8 *)to, from, 1, ret, 1); | |
103 | return ret; | |
104 | case 2: | |
105 | __get_user_size(*(u16 *)to, from, 2, ret, 2); | |
106 | return ret; | |
107 | case 4: | |
108 | __get_user_size(*(u32 *)to, from, 4, ret, 4); | |
109 | return ret; | |
110 | } | |
111 | } | |
112 | return __copy_from_user_ll_nozero(to, from, n); | |
113 | } | |
9c7fff6e RD |
114 | |
115 | /** | |
116 | * __copy_from_user: - Copy a block of data from user space, with less checking. | |
117 | * @to: Destination address, in kernel space. | |
118 | * @from: Source address, in user space. | |
119 | * @n: Number of bytes to copy. | |
120 | * | |
121 | * Context: User context only. This function may sleep. | |
122 | * | |
123 | * Copy data from user space to kernel space. Caller must check | |
124 | * the specified block with access_ok() before calling this function. | |
125 | * | |
126 | * Returns number of bytes that could not be copied. | |
127 | * On success, this will be zero. | |
128 | * | |
129 | * If some data could not be copied, this function will pad the copied | |
130 | * data to the requested size using zero bytes. | |
131 | * | |
132 | * An alternate version - __copy_from_user_inatomic() - may be called from | |
133 | * atomic context and will fail rather than sleep. In this case the | |
134 | * uncopied bytes will *NOT* be padded with zeros. See fs/filemap.h | |
135 | * for explanation of why this is needed. | |
136 | */ | |
7c12d811 N |
137 | static __always_inline unsigned long |
138 | __copy_from_user(void *to, const void __user *from, unsigned long n) | |
139 | { | |
140 | might_sleep(); | |
1da177e4 LT |
141 | if (__builtin_constant_p(n)) { |
142 | unsigned long ret; | |
143 | ||
144 | switch (n) { | |
145 | case 1: | |
146 | __get_user_size(*(u8 *)to, from, 1, ret, 1); | |
147 | return ret; | |
148 | case 2: | |
149 | __get_user_size(*(u16 *)to, from, 2, ret, 2); | |
150 | return ret; | |
151 | case 4: | |
152 | __get_user_size(*(u32 *)to, from, 4, ret, 4); | |
153 | return ret; | |
154 | } | |
155 | } | |
156 | return __copy_from_user_ll(to, from, n); | |
157 | } | |
158 | ||
7c12d811 | 159 | static __always_inline unsigned long __copy_from_user_nocache(void *to, |
c22ce143 HY |
160 | const void __user *from, unsigned long n) |
161 | { | |
7c12d811 | 162 | might_sleep(); |
c22ce143 HY |
163 | if (__builtin_constant_p(n)) { |
164 | unsigned long ret; | |
165 | ||
166 | switch (n) { | |
167 | case 1: | |
168 | __get_user_size(*(u8 *)to, from, 1, ret, 1); | |
169 | return ret; | |
170 | case 2: | |
171 | __get_user_size(*(u16 *)to, from, 2, ret, 2); | |
172 | return ret; | |
173 | case 4: | |
174 | __get_user_size(*(u32 *)to, from, 4, ret, 4); | |
175 | return ret; | |
176 | } | |
177 | } | |
178 | return __copy_from_user_ll_nocache(to, from, n); | |
179 | } | |
180 | ||
652050ae | 181 | static __always_inline unsigned long |
b1fcec7f JP |
182 | __copy_from_user_inatomic_nocache(void *to, const void __user *from, |
183 | unsigned long n) | |
1da177e4 | 184 | { |
7c12d811 | 185 | return __copy_from_user_ll_nocache_nozero(to, from, n); |
c22ce143 HY |
186 | } |
187 | ||
1da177e4 | 188 | unsigned long __must_check copy_to_user(void __user *to, |
b1fcec7f | 189 | const void *from, unsigned long n); |
1da177e4 | 190 | unsigned long __must_check copy_from_user(void *to, |
b1fcec7f JP |
191 | const void __user *from, |
192 | unsigned long n); | |
1da177e4 | 193 | long __must_check strncpy_from_user(char *dst, const char __user *src, |
b1fcec7f | 194 | long count); |
1da177e4 | 195 | long __must_check __strncpy_from_user(char *dst, |
b1fcec7f | 196 | const char __user *src, long count); |
1da177e4 LT |
197 | |
198 | /** | |
199 | * strlen_user: - Get the size of a string in user space. | |
200 | * @str: The string to measure. | |
201 | * | |
202 | * Context: User context only. This function may sleep. | |
203 | * | |
204 | * Get the size of a NUL-terminated string in user space. | |
205 | * | |
206 | * Returns the size of the string INCLUDING the terminating NUL. | |
207 | * On exception, returns 0. | |
208 | * | |
209 | * If there is a limit on the length of a valid string, you may wish to | |
210 | * consider using strnlen_user() instead. | |
211 | */ | |
48dd9343 | 212 | #define strlen_user(str) strnlen_user(str, LONG_MAX) |
1da177e4 LT |
213 | |
214 | long strnlen_user(const char __user *str, long n); | |
215 | unsigned long __must_check clear_user(void __user *mem, unsigned long len); | |
216 | unsigned long __must_check __clear_user(void __user *mem, unsigned long len); | |
217 | ||
218 | #endif /* __i386_UACCESS_H */ |