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Arnd Bergmanneed417d2009-05-13 22:56:37 +00001#ifndef __ASM_GENERIC_UACCESS_H
2#define __ASM_GENERIC_UACCESS_H
3
4/*
5 * User space memory access functions, these should work
6 * on a ny machine that has kernel and user data in the same
7 * address space, e.g. all NOMMU machines.
8 */
9#include <linux/sched.h>
10#include <linux/mm.h>
11#include <linux/string.h>
12
13#include <asm/segment.h>
14
15#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
16
17#ifndef KERNEL_DS
18#define KERNEL_DS MAKE_MM_SEG(~0UL)
19#endif
20
21#ifndef USER_DS
22#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
23#endif
24
25#ifndef get_fs
26#define get_ds() (KERNEL_DS)
27#define get_fs() (current_thread_info()->addr_limit)
28
29static inline void set_fs(mm_segment_t fs)
30{
31 current_thread_info()->addr_limit = fs;
32}
33#endif
34
35#define segment_eq(a, b) ((a).seg == (b).seg)
36
37#define VERIFY_READ 0
38#define VERIFY_WRITE 1
39
40#define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size))
41
42/*
43 * The architecture should really override this if possible, at least
44 * doing a check on the get_fs()
45 */
46#ifndef __access_ok
47static inline int __access_ok(unsigned long addr, unsigned long size)
48{
49 return 1;
50}
51#endif
52
53/*
54 * The exception table consists of pairs of addresses: the first is the
55 * address of an instruction that is allowed to fault, and the second is
56 * the address at which the program should continue. No registers are
57 * modified, so it is entirely up to the continuation code to figure out
58 * what to do.
59 *
60 * All the routines below use bits of fixup code that are out of line
61 * with the main instruction path. This means when everything is well,
62 * we don't even have to jump over them. Further, they do not intrude
63 * on our cache or tlb entries.
64 */
65
66struct exception_table_entry
67{
68 unsigned long insn, fixup;
69};
70
71/* Returns 0 if exception not found and fixup otherwise. */
72extern unsigned long search_exception_table(unsigned long);
73
74/*
75 * architectures with an MMU should override these two
76 */
77#ifndef __copy_from_user
78static inline __must_check long __copy_from_user(void *to,
79 const void __user * from, unsigned long n)
80{
81 if (__builtin_constant_p(n)) {
82 switch(n) {
83 case 1:
84 *(u8 *)to = *(u8 __force *)from;
85 return 0;
86 case 2:
87 *(u16 *)to = *(u16 __force *)from;
88 return 0;
89 case 4:
90 *(u32 *)to = *(u32 __force *)from;
91 return 0;
92#ifdef CONFIG_64BIT
93 case 8:
94 *(u64 *)to = *(u64 __force *)from;
95 return 0;
96#endif
97 default:
98 break;
99 }
100 }
101
102 memcpy(to, (const void __force *)from, n);
103 return 0;
104}
105#endif
106
107#ifndef __copy_to_user
108static inline __must_check long __copy_to_user(void __user *to,
109 const void *from, unsigned long n)
110{
111 if (__builtin_constant_p(n)) {
112 switch(n) {
113 case 1:
114 *(u8 __force *)to = *(u8 *)from;
115 return 0;
116 case 2:
117 *(u16 __force *)to = *(u16 *)from;
118 return 0;
119 case 4:
120 *(u32 __force *)to = *(u32 *)from;
121 return 0;
122#ifdef CONFIG_64BIT
123 case 8:
124 *(u64 __force *)to = *(u64 *)from;
125 return 0;
126#endif
127 default:
128 break;
129 }
130 }
131
132 memcpy((void __force *)to, from, n);
133 return 0;
134}
135#endif
136
137/*
138 * These are the main single-value transfer routines. They automatically
139 * use the right size if we just have the right pointer type.
140 * This version just falls back to copy_{from,to}_user, which should
141 * provide a fast-path for small values.
142 */
143#define __put_user(x, ptr) \
144({ \
145 __typeof__(*(ptr)) __x = (x); \
146 int __pu_err = -EFAULT; \
147 __chk_user_ptr(ptr); \
148 switch (sizeof (*(ptr))) { \
149 case 1: \
150 case 2: \
151 case 4: \
152 case 8: \
153 __pu_err = __put_user_fn(sizeof (*(ptr)), \
154 ptr, &__x); \
155 break; \
156 default: \
157 __put_user_bad(); \
158 break; \
159 } \
160 __pu_err; \
161})
162
163#define put_user(x, ptr) \
164({ \
165 might_sleep(); \
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400166 access_ok(VERIFY_WRITE, ptr, sizeof(*ptr)) ? \
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000167 __put_user(x, ptr) : \
168 -EFAULT; \
169})
170
171static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
172{
173 size = __copy_to_user(ptr, x, size);
174 return size ? -EFAULT : size;
175}
176
177extern int __put_user_bad(void) __attribute__((noreturn));
178
179#define __get_user(x, ptr) \
180({ \
181 int __gu_err = -EFAULT; \
182 __chk_user_ptr(ptr); \
183 switch (sizeof(*(ptr))) { \
184 case 1: { \
185 unsigned char __x; \
186 __gu_err = __get_user_fn(sizeof (*(ptr)), \
187 ptr, &__x); \
188 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
189 break; \
190 }; \
191 case 2: { \
192 unsigned short __x; \
193 __gu_err = __get_user_fn(sizeof (*(ptr)), \
194 ptr, &__x); \
195 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
196 break; \
197 }; \
198 case 4: { \
199 unsigned int __x; \
200 __gu_err = __get_user_fn(sizeof (*(ptr)), \
201 ptr, &__x); \
202 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
203 break; \
204 }; \
205 case 8: { \
206 unsigned long long __x; \
207 __gu_err = __get_user_fn(sizeof (*(ptr)), \
208 ptr, &__x); \
209 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
210 break; \
211 }; \
212 default: \
213 __get_user_bad(); \
214 break; \
215 } \
216 __gu_err; \
217})
218
219#define get_user(x, ptr) \
220({ \
221 might_sleep(); \
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400222 access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ? \
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000223 __get_user(x, ptr) : \
224 -EFAULT; \
225})
226
227static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
228{
229 size = __copy_from_user(x, ptr, size);
230 return size ? -EFAULT : size;
231}
232
233extern int __get_user_bad(void) __attribute__((noreturn));
234
235#ifndef __copy_from_user_inatomic
236#define __copy_from_user_inatomic __copy_from_user
237#endif
238
239#ifndef __copy_to_user_inatomic
240#define __copy_to_user_inatomic __copy_to_user
241#endif
242
243static inline long copy_from_user(void *to,
244 const void __user * from, unsigned long n)
245{
246 might_sleep();
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400247 if (access_ok(VERIFY_READ, from, n))
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000248 return __copy_from_user(to, from, n);
249 else
250 return n;
251}
252
253static inline long copy_to_user(void __user *to,
254 const void *from, unsigned long n)
255{
256 might_sleep();
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400257 if (access_ok(VERIFY_WRITE, to, n))
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000258 return __copy_to_user(to, from, n);
259 else
260 return n;
261}
262
263/*
264 * Copy a null terminated string from userspace.
265 */
266#ifndef __strncpy_from_user
267static inline long
268__strncpy_from_user(char *dst, const char __user *src, long count)
269{
270 char *tmp;
271 strncpy(dst, (const char __force *)src, count);
272 for (tmp = dst; *tmp && count > 0; tmp++, count--)
273 ;
274 return (tmp - dst);
275}
276#endif
277
278static inline long
279strncpy_from_user(char *dst, const char __user *src, long count)
280{
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400281 if (!access_ok(VERIFY_READ, src, 1))
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000282 return -EFAULT;
283 return __strncpy_from_user(dst, src, count);
284}
285
286/*
287 * Return the size of a string (including the ending 0)
288 *
289 * Return 0 on exception, a value greater than N if too long
290 */
GuanXuetao7f509a92011-01-15 18:08:09 +0800291#ifndef __strnlen_user
Mark Salter830f5802011-10-04 09:17:36 -0400292#define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
GuanXuetao7f509a92011-01-15 18:08:09 +0800293#endif
294
Mark Salter830f5802011-10-04 09:17:36 -0400295/*
296 * Unlike strnlen, strnlen_user includes the nul terminator in
297 * its returned count. Callers should check for a returned value
298 * greater than N as an indication the string is too long.
299 */
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000300static inline long strnlen_user(const char __user *src, long n)
301{
Mike Frysinger98448132009-06-14 02:00:02 -0400302 if (!access_ok(VERIFY_READ, src, 1))
303 return 0;
GuanXuetao7f509a92011-01-15 18:08:09 +0800304 return __strnlen_user(src, n);
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000305}
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000306
307static inline long strlen_user(const char __user *src)
308{
309 return strnlen_user(src, 32767);
310}
311
312/*
313 * Zero Userspace
314 */
315#ifndef __clear_user
316static inline __must_check unsigned long
317__clear_user(void __user *to, unsigned long n)
318{
319 memset((void __force *)to, 0, n);
320 return 0;
321}
322#endif
323
324static inline __must_check unsigned long
325clear_user(void __user *to, unsigned long n)
326{
327 might_sleep();
Mike Frysingera9ede5b2009-06-14 02:00:03 -0400328 if (!access_ok(VERIFY_WRITE, to, n))
Arnd Bergmanneed417d2009-05-13 22:56:37 +0000329 return n;
330
331 return __clear_user(to, n);
332}
333
334#endif /* __ASM_GENERIC_UACCESS_H */