1 #ifndef _ASMARM_UACCESS_H
2 #define _ASMARM_UACCESS_H
3
4 /*
5 * User space memory access functions
6 */
7 #include <linux/sched.h>
8 #include <asm/errno.h>
9
10 #define VERIFY_READ 0
11 #define VERIFY_WRITE 1
12
13 /*
14 * The exception table consists of pairs of addresses: the first is the
15 * address of an instruction that is allowed to fault, and the second is
16 * the address at which the program should continue. No registers are
17 * modified, so it is entirely up to the continuation code to figure out
18 * what to do.
19 *
20 * All the routines below use bits of fixup code that are out of line
21 * with the main instruction path. This means when everything is well,
22 * we don't even have to jump over them. Further, they do not intrude
23 * on our cache or tlb entries.
24 */
25
26 struct exception_table_entry
27 {
28 unsigned long insn, fixup;
29 };
30
31 /* Returns 0 if exception not found and fixup otherwise. */
32 extern unsigned long search_exception_table(unsigned long);
33
34 #define get_ds() (KERNEL_DS)
35 #define get_fs() (current->addr_limit)
36 #define segment_eq(a,b) ((a) == (b))
37
38 #include <asm/proc/uaccess.h>
39
40 #define access_ok(type,addr,size) (__range_ok(addr,size) == 0)
41
verify_area(int type,const void * addr,unsigned long size)42 static inline int verify_area(int type, const void * addr, unsigned long size)
43 {
44 return access_ok(type, addr, size) ? 0 : -EFAULT;
45 }
46
47 /*
48 * Single-value transfer routines. They automatically use the right
49 * size if we just have the right pointer type. Note that the functions
50 * which read from user space (*get_*) need to take care not to leak
51 * kernel data even if the calling code is buggy and fails to check
52 * the return value. This means zeroing out the destination variable
53 * or buffer on error. Normally this is done out of line by the
54 * fixup code, but there are a few places where it intrudes on the
55 * main code path. When we only write to user space, there is no
56 * problem.
57 *
58 * The "__xxx" versions of the user access functions do not verify the
59 * address space - it must have been done previously with a separate
60 * "access_ok()" call.
61 *
62 * The "xxx_error" versions set the third argument to EFAULT if an
63 * error occurs, and leave it unchanged on success. Note that these
64 * versions are void (ie, don't return a value as such).
65 */
66
67 extern int __get_user_1(void *);
68 extern int __get_user_2(void *);
69 extern int __get_user_4(void *);
70 extern int __get_user_8(void *);
71 extern int __get_user_bad(void);
72
73 #define __get_user_x(__r1,__p,__e,__s,__i...) \
74 __asm__ __volatile__ ("bl __get_user_" #__s \
75 : "=&r" (__e), "=r" (__r1) \
76 : "0" (__p) \
77 : __i)
78
79 #define get_user(x,p) \
80 ({ \
81 const register typeof(*(p)) *__p asm("r0") = (p); \
82 register typeof(*(p)) __r1 asm("r1"); \
83 register int __e asm("r0"); \
84 switch (sizeof(*(p))) { \
85 case 1: \
86 __get_user_x(__r1, __p, __e, 1, "lr"); \
87 break; \
88 case 2: \
89 __get_user_x(__r1, __p, __e, 2, "r2", "lr"); \
90 break; \
91 case 4: \
92 __get_user_x(__r1, __p, __e, 4, "lr"); \
93 break; \
94 case 8: \
95 __get_user_x(__r1, __p, __e, 8, "lr"); \
96 break; \
97 default: __e = __get_user_bad(); break; \
98 } \
99 x = __r1; \
100 __e; \
101 })
102
103 #define __get_user(x,p) __get_user_nocheck((x),(p),sizeof(*(p)))
104 #define __get_user_error(x,p,e) __get_user_nocheck_error((x),(p),sizeof(*(p)),(e))
105
106 extern int __put_user_1(void *, unsigned int);
107 extern int __put_user_2(void *, unsigned int);
108 extern int __put_user_4(void *, unsigned int);
109 extern int __put_user_8(void *, unsigned long long);
110 extern int __put_user_bad(void);
111
112 #define __put_user_x(__r1,__p,__e,__s,__i...) \
113 __asm__ __volatile__ ("bl __put_user_" #__s \
114 : "=&r" (__e) \
115 : "0" (__p), "r" (__r1) \
116 : __i)
117
118 #define put_user(x,p) \
119 ({ \
120 const register typeof(*(p)) __r1 asm("r1") = (x); \
121 const register typeof(*(p)) *__p asm("r0") = (p); \
122 register int __e asm("r0"); \
123 switch (sizeof(*(p))) { \
124 case 1: \
125 __put_user_x(__r1, __p, __e, 1, "r2", "lr"); \
126 break; \
127 case 2: \
128 __put_user_x(__r1, __p, __e, 2, "r2", "lr"); \
129 break; \
130 case 4: \
131 __put_user_x(__r1, __p, __e, 4, "r2", "lr"); \
132 break; \
133 case 8: \
134 __put_user_x(__r1, __p, __e, 8, "ip", "lr"); \
135 break; \
136 default: __e = __put_user_bad(); break; \
137 } \
138 __e; \
139 })
140
141 #define __put_user(x,p) __put_user_nocheck((__typeof(*(p)))(x),(p),sizeof(*(p)))
142 #define __put_user_error(x,p,e) __put_user_nocheck_error((x),(p),sizeof(*(p)),(e))
143
copy_from_user(void * to,const void * from,unsigned long n)144 static __inline__ unsigned long copy_from_user(void *to, const void *from, unsigned long n)
145 {
146 if (access_ok(VERIFY_READ, from, n))
147 __do_copy_from_user(to, from, n);
148 else /* security hole - plug it */
149 memzero(to, n);
150 return n;
151 }
152
__copy_from_user(void * to,const void * from,unsigned long n)153 static __inline__ unsigned long __copy_from_user(void *to, const void *from, unsigned long n)
154 {
155 __do_copy_from_user(to, from, n);
156 return n;
157 }
158
copy_to_user(void * to,const void * from,unsigned long n)159 static __inline__ unsigned long copy_to_user(void *to, const void *from, unsigned long n)
160 {
161 if (access_ok(VERIFY_WRITE, to, n))
162 __do_copy_to_user(to, from, n);
163 return n;
164 }
165
__copy_to_user(void * to,const void * from,unsigned long n)166 static __inline__ unsigned long __copy_to_user(void *to, const void *from, unsigned long n)
167 {
168 __do_copy_to_user(to, from, n);
169 return n;
170 }
171
clear_user(void * to,unsigned long n)172 static __inline__ unsigned long clear_user (void *to, unsigned long n)
173 {
174 if (access_ok(VERIFY_WRITE, to, n))
175 __do_clear_user(to, n);
176 return n;
177 }
178
__clear_user(void * to,unsigned long n)179 static __inline__ unsigned long __clear_user (void *to, unsigned long n)
180 {
181 __do_clear_user(to, n);
182 return n;
183 }
184
strncpy_from_user(char * dst,const char * src,long count)185 static __inline__ long strncpy_from_user (char *dst, const char *src, long count)
186 {
187 long res = -EFAULT;
188 if (access_ok(VERIFY_READ, src, 1))
189 __do_strncpy_from_user(dst, src, count, res);
190 return res;
191 }
192
__strncpy_from_user(char * dst,const char * src,long count)193 static __inline__ long __strncpy_from_user (char *dst, const char *src, long count)
194 {
195 long res;
196 __do_strncpy_from_user(dst, src, count, res);
197 return res;
198 }
199
200 #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
201
strnlen_user(const char * s,long n)202 static inline long strnlen_user(const char *s, long n)
203 {
204 unsigned long res = 0;
205
206 if (__addr_ok(s))
207 __do_strnlen_user(s, n, res);
208
209 return res;
210 }
211
212 /*
213 * These are the work horses of the get/put_user functions
214 */
215 #if 0
216 #define __get_user_check(x,ptr,size) \
217 ({ \
218 long __gu_err = -EFAULT, __gu_val = 0; \
219 const __typeof__(*(ptr)) *__gu_addr = (ptr); \
220 if (access_ok(VERIFY_READ,__gu_addr,size)) { \
221 __gu_err = 0; \
222 __get_user_size(__gu_val,__gu_addr,(size),__gu_err); \
223 } \
224 (x) = (__typeof__(*(ptr)))__gu_val; \
225 __gu_err; \
226 })
227 #endif
228
229 #define __get_user_nocheck(x,ptr,size) \
230 ({ \
231 long __gu_err = 0, __gu_val; \
232 __get_user_size(__gu_val,(ptr),(size),__gu_err); \
233 (x) = (__typeof__(*(ptr)))__gu_val; \
234 __gu_err; \
235 })
236
237 #define __get_user_nocheck_error(x,ptr,size,err) \
238 ({ \
239 long __gu_val; \
240 __get_user_size(__gu_val,(ptr),(size),(err)); \
241 (x) = (__typeof__(*(ptr)))__gu_val; \
242 (void) 0; \
243 })
244
245 #define __put_user_check(x,ptr,size) \
246 ({ \
247 long __pu_err = -EFAULT; \
248 __typeof__(*(ptr)) *__pu_addr = (ptr); \
249 if (access_ok(VERIFY_WRITE,__pu_addr,size)) { \
250 __pu_err = 0; \
251 __put_user_size((x),__pu_addr,(size),__pu_err); \
252 } \
253 __pu_err; \
254 })
255
256 #define __put_user_nocheck(x,ptr,size) \
257 ({ \
258 long __pu_err = 0; \
259 __typeof__(*(ptr)) *__pu_addr = (ptr); \
260 __put_user_size((x),__pu_addr,(size),__pu_err); \
261 __pu_err; \
262 })
263
264 #define __put_user_nocheck_error(x,ptr,size,err) \
265 ({ \
266 __put_user_size((x),(ptr),(size),err); \
267 (void) 0; \
268 })
269
270 #define __get_user_size(x,ptr,size,retval) \
271 do { \
272 switch (size) { \
273 case 1: __get_user_asm_byte(x,ptr,retval); break; \
274 case 2: __get_user_asm_half(x,ptr,retval); break; \
275 case 4: __get_user_asm_word(x,ptr,retval); break; \
276 default: (x) = __get_user_bad(); \
277 } \
278 } while (0)
279
280 #define __put_user_size(x,ptr,size,retval) \
281 do { \
282 switch (size) { \
283 case 1: __put_user_asm_byte(x,ptr,retval); break; \
284 case 2: __put_user_asm_half(x,ptr,retval); break; \
285 case 4: __put_user_asm_word(x,ptr,retval); break; \
286 default: __put_user_bad(); \
287 } \
288 } while (0)
289
290 #endif /* _ASMARM_UACCESS_H */
291