1 #ifndef __ASM_GENERIC_UACCESS_H
2 #define __ASM_GENERIC_UACCESS_H
3
4 /*
5 * User space memory access functions, these should work
6 * on any 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/string.h>
11
12 #include <asm/segment.h>
13
14 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
15
16 #ifndef KERNEL_DS
17 #define KERNEL_DS MAKE_MM_SEG(~0UL)
18 #endif
19
20 #ifndef USER_DS
21 #define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
22 #endif
23
24 #ifndef get_fs
25 #define get_ds() (KERNEL_DS)
26 #define get_fs() (current_thread_info()->addr_limit)
27
set_fs(mm_segment_t fs)28 static inline void set_fs(mm_segment_t fs)
29 {
30 current_thread_info()->addr_limit = fs;
31 }
32 #endif
33
34 #ifndef segment_eq
35 #define segment_eq(a, b) ((a).seg == (b).seg)
36 #endif
37
38 #define VERIFY_READ 0
39 #define VERIFY_WRITE 1
40
41 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size))
42
43 /*
44 * The architecture should really override this if possible, at least
45 * doing a check on the get_fs()
46 */
47 #ifndef __access_ok
__access_ok(unsigned long addr,unsigned long size)48 static inline int __access_ok(unsigned long addr, unsigned long size)
49 {
50 return 1;
51 }
52 #endif
53
54 /*
55 * The exception table consists of pairs of addresses: the first is the
56 * address of an instruction that is allowed to fault, and the second is
57 * the address at which the program should continue. No registers are
58 * modified, so it is entirely up to the continuation code to figure out
59 * what to do.
60 *
61 * All the routines below use bits of fixup code that are out of line
62 * with the main instruction path. This means when everything is well,
63 * we don't even have to jump over them. Further, they do not intrude
64 * on our cache or tlb entries.
65 */
66
67 struct exception_table_entry
68 {
69 unsigned long insn, fixup;
70 };
71
72 /*
73 * architectures with an MMU should override these two
74 */
75 #ifndef __copy_from_user
__copy_from_user(void * to,const void __user * from,unsigned long n)76 static inline __must_check long __copy_from_user(void *to,
77 const void __user * from, unsigned long n)
78 {
79 if (__builtin_constant_p(n)) {
80 switch(n) {
81 case 1:
82 *(u8 *)to = *(u8 __force *)from;
83 return 0;
84 case 2:
85 *(u16 *)to = *(u16 __force *)from;
86 return 0;
87 case 4:
88 *(u32 *)to = *(u32 __force *)from;
89 return 0;
90 #ifdef CONFIG_64BIT
91 case 8:
92 *(u64 *)to = *(u64 __force *)from;
93 return 0;
94 #endif
95 default:
96 break;
97 }
98 }
99
100 memcpy(to, (const void __force *)from, n);
101 return 0;
102 }
103 #endif
104
105 #ifndef __copy_to_user
__copy_to_user(void __user * to,const void * from,unsigned long n)106 static inline __must_check long __copy_to_user(void __user *to,
107 const void *from, unsigned long n)
108 {
109 if (__builtin_constant_p(n)) {
110 switch(n) {
111 case 1:
112 *(u8 __force *)to = *(u8 *)from;
113 return 0;
114 case 2:
115 *(u16 __force *)to = *(u16 *)from;
116 return 0;
117 case 4:
118 *(u32 __force *)to = *(u32 *)from;
119 return 0;
120 #ifdef CONFIG_64BIT
121 case 8:
122 *(u64 __force *)to = *(u64 *)from;
123 return 0;
124 #endif
125 default:
126 break;
127 }
128 }
129
130 memcpy((void __force *)to, from, n);
131 return 0;
132 }
133 #endif
134
135 /*
136 * These are the main single-value transfer routines. They automatically
137 * use the right size if we just have the right pointer type.
138 * This version just falls back to copy_{from,to}_user, which should
139 * provide a fast-path for small values.
140 */
141 #define __put_user(x, ptr) \
142 ({ \
143 __typeof__(*(ptr)) __x = (x); \
144 int __pu_err = -EFAULT; \
145 __chk_user_ptr(ptr); \
146 switch (sizeof (*(ptr))) { \
147 case 1: \
148 case 2: \
149 case 4: \
150 case 8: \
151 __pu_err = __put_user_fn(sizeof (*(ptr)), \
152 ptr, &__x); \
153 break; \
154 default: \
155 __put_user_bad(); \
156 break; \
157 } \
158 __pu_err; \
159 })
160
161 #define put_user(x, ptr) \
162 ({ \
163 void *__p = (ptr); \
164 might_fault(); \
165 access_ok(VERIFY_WRITE, __p, sizeof(*ptr)) ? \
166 __put_user((x), ((__typeof__(*(ptr)) *)__p)) : \
167 -EFAULT; \
168 })
169
170 #ifndef __put_user_fn
171
__put_user_fn(size_t size,void __user * ptr,void * x)172 static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
173 {
174 size = __copy_to_user(ptr, x, size);
175 return size ? -EFAULT : size;
176 }
177
178 #define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
179
180 #endif
181
182 extern int __put_user_bad(void) __attribute__((noreturn));
183
184 #define __get_user(x, ptr) \
185 ({ \
186 int __gu_err = -EFAULT; \
187 __chk_user_ptr(ptr); \
188 switch (sizeof(*(ptr))) { \
189 case 1: { \
190 unsigned char __x; \
191 __gu_err = __get_user_fn(sizeof (*(ptr)), \
192 ptr, &__x); \
193 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
194 break; \
195 }; \
196 case 2: { \
197 unsigned short __x; \
198 __gu_err = __get_user_fn(sizeof (*(ptr)), \
199 ptr, &__x); \
200 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
201 break; \
202 }; \
203 case 4: { \
204 unsigned int __x; \
205 __gu_err = __get_user_fn(sizeof (*(ptr)), \
206 ptr, &__x); \
207 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
208 break; \
209 }; \
210 case 8: { \
211 unsigned long long __x; \
212 __gu_err = __get_user_fn(sizeof (*(ptr)), \
213 ptr, &__x); \
214 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
215 break; \
216 }; \
217 default: \
218 __get_user_bad(); \
219 break; \
220 } \
221 __gu_err; \
222 })
223
224 #define get_user(x, ptr) \
225 ({ \
226 const void *__p = (ptr); \
227 might_fault(); \
228 access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \
229 __get_user((x), (__typeof__(*(ptr)) *)__p) : \
230 ((x) = (__typeof__(*(ptr)))0,-EFAULT); \
231 })
232
233 #ifndef __get_user_fn
__get_user_fn(size_t size,const void __user * ptr,void * x)234 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
235 {
236 size_t n = __copy_from_user(x, ptr, size);
237 if (unlikely(n)) {
238 memset(x + (size - n), 0, n);
239 return -EFAULT;
240 }
241 return 0;
242 }
243
244 #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
245
246 #endif
247
248 extern int __get_user_bad(void) __attribute__((noreturn));
249
250 #ifndef __copy_from_user_inatomic
251 #define __copy_from_user_inatomic __copy_from_user
252 #endif
253
254 #ifndef __copy_to_user_inatomic
255 #define __copy_to_user_inatomic __copy_to_user
256 #endif
257
copy_from_user(void * to,const void __user * from,unsigned long n)258 static inline long copy_from_user(void *to,
259 const void __user * from, unsigned long n)
260 {
261 unsigned long res = n;
262 might_fault();
263 if (likely(access_ok(VERIFY_READ, from, n)))
264 res = __copy_from_user(to, from, n);
265 if (unlikely(res))
266 memset(to + (n - res), 0, res);
267 return res;
268 }
269
copy_to_user(void __user * to,const void * from,unsigned long n)270 static inline long copy_to_user(void __user *to,
271 const void *from, unsigned long n)
272 {
273 might_fault();
274 if (access_ok(VERIFY_WRITE, to, n))
275 return __copy_to_user(to, from, n);
276 else
277 return n;
278 }
279
280 /*
281 * Copy a null terminated string from userspace.
282 */
283 #ifndef __strncpy_from_user
284 static inline long
__strncpy_from_user(char * dst,const char __user * src,long count)285 __strncpy_from_user(char *dst, const char __user *src, long count)
286 {
287 char *tmp;
288 strncpy(dst, (const char __force *)src, count);
289 for (tmp = dst; *tmp && count > 0; tmp++, count--)
290 ;
291 return (tmp - dst);
292 }
293 #endif
294
295 static inline long
strncpy_from_user(char * dst,const char __user * src,long count)296 strncpy_from_user(char *dst, const char __user *src, long count)
297 {
298 if (!access_ok(VERIFY_READ, src, 1))
299 return -EFAULT;
300 return __strncpy_from_user(dst, src, count);
301 }
302
303 /*
304 * Return the size of a string (including the ending 0)
305 *
306 * Return 0 on exception, a value greater than N if too long
307 */
308 #ifndef __strnlen_user
309 #define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
310 #endif
311
312 /*
313 * Unlike strnlen, strnlen_user includes the nul terminator in
314 * its returned count. Callers should check for a returned value
315 * greater than N as an indication the string is too long.
316 */
strnlen_user(const char __user * src,long n)317 static inline long strnlen_user(const char __user *src, long n)
318 {
319 if (!access_ok(VERIFY_READ, src, 1))
320 return 0;
321 return __strnlen_user(src, n);
322 }
323
strlen_user(const char __user * src)324 static inline long strlen_user(const char __user *src)
325 {
326 return strnlen_user(src, 32767);
327 }
328
329 /*
330 * Zero Userspace
331 */
332 #ifndef __clear_user
333 static inline __must_check unsigned long
__clear_user(void __user * to,unsigned long n)334 __clear_user(void __user *to, unsigned long n)
335 {
336 memset((void __force *)to, 0, n);
337 return 0;
338 }
339 #endif
340
341 static inline __must_check unsigned long
clear_user(void __user * to,unsigned long n)342 clear_user(void __user *to, unsigned long n)
343 {
344 might_fault();
345 if (!access_ok(VERIFY_WRITE, to, n))
346 return n;
347
348 return __clear_user(to, n);
349 }
350
351 #endif /* __ASM_GENERIC_UACCESS_H */
352