File: /usr/src/linux/include/asm-arm/uaccess.h
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
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 #define get_user(x,p) __get_user_check((x),(p),sizeof(*(p)))
67 #define __get_user(x,p) __get_user_nocheck((x),(p),sizeof(*(p)))
68 #define __get_user_error(x,p,e) __get_user_nocheck_error((x),(p),sizeof(*(p)),(e))
69
70 #define put_user(x,p) __put_user_check((__typeof(*(p)))(x),(p),sizeof(*(p)))
71 #define __put_user(x,p) __put_user_nocheck((__typeof(*(p)))(x),(p),sizeof(*(p)))
72 #define __put_user_error(x,p,e) __put_user_nocheck_error((x),(p),sizeof(*(p)),(e))
73
74 static __inline__ unsigned long copy_from_user(void *to, const void *from, unsigned long n)
75 {
76 if (access_ok(VERIFY_READ, from, n))
77 __do_copy_from_user(to, from, n);
78 else /* security hole - plug it */
79 memzero(to, n);
80 return n;
81 }
82
83 static __inline__ unsigned long __copy_from_user(void *to, const void *from, unsigned long n)
84 {
85 __do_copy_from_user(to, from, n);
86 return n;
87 }
88
89 static __inline__ unsigned long copy_to_user(void *to, const void *from, unsigned long n)
90 {
91 if (access_ok(VERIFY_WRITE, to, n))
92 __do_copy_to_user(to, from, n);
93 return n;
94 }
95
96 static __inline__ unsigned long __copy_to_user(void *to, const void *from, unsigned long n)
97 {
98 __do_copy_to_user(to, from, n);
99 return n;
100 }
101
102 static __inline__ unsigned long clear_user (void *to, unsigned long n)
103 {
104 if (access_ok(VERIFY_WRITE, to, n))
105 __do_clear_user(to, n);
106 return n;
107 }
108
109 static __inline__ unsigned long __clear_user (void *to, unsigned long n)
110 {
111 __do_clear_user(to, n);
112 return n;
113 }
114
115 static __inline__ long strncpy_from_user (char *dst, const char *src, long count)
116 {
117 long res = -EFAULT;
118 if (access_ok(VERIFY_READ, src, 1))
119 __do_strncpy_from_user(dst, src, count, res);
120 return res;
121 }
122
123 static __inline__ long __strncpy_from_user (char *dst, const char *src, long count)
124 {
125 long res;
126 __do_strncpy_from_user(dst, src, count, res);
127 return res;
128 }
129
130 #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
131
132 static inline long strnlen_user(const char *s, long n)
133 {
134 unsigned long res = 0;
135
136 if (__addr_ok(s))
137 __do_strnlen_user(s, n, res);
138
139 return res;
140 }
141
142 /*
143 * These are the work horses of the get/put_user functions
144 */
145 #define __get_user_check(x,ptr,size) \
146 ({ \
147 long __gu_err = -EFAULT, __gu_val = 0; \
148 const __typeof__(*(ptr)) *__gu_addr = (ptr); \
149 if (access_ok(VERIFY_READ,__gu_addr,size)) { \
150 __gu_err = 0; \
151 __get_user_size(__gu_val,__gu_addr,(size),__gu_err); \
152 } \
153 (x) = (__typeof__(*(ptr)))__gu_val; \
154 __gu_err; \
155 })
156
157 #define __get_user_nocheck(x,ptr,size) \
158 ({ \
159 long __gu_err = 0, __gu_val; \
160 __get_user_size(__gu_val,(ptr),(size),__gu_err); \
161 (x) = (__typeof__(*(ptr)))__gu_val; \
162 __gu_err; \
163 })
164
165 #define __get_user_nocheck_error(x,ptr,size,err) \
166 ({ \
167 long __gu_val; \
168 __get_user_size(__gu_val,(ptr),(size),(err)); \
169 (x) = (__typeof__(*(ptr)))__gu_val; \
170 (void) 0; \
171 })
172
173 #define __put_user_check(x,ptr,size) \
174 ({ \
175 long __pu_err = -EFAULT; \
176 __typeof__(*(ptr)) *__pu_addr = (ptr); \
177 if (access_ok(VERIFY_WRITE,__pu_addr,size)) { \
178 __pu_err = 0; \
179 __put_user_size((x),__pu_addr,(size),__pu_err); \
180 } \
181 __pu_err; \
182 })
183
184 #define __put_user_nocheck(x,ptr,size) \
185 ({ \
186 long __pu_err = 0; \
187 __typeof__(*(ptr)) *__pu_addr = (ptr); \
188 __put_user_size((x),__pu_addr,(size),__pu_err); \
189 __pu_err; \
190 })
191
192 #define __put_user_nocheck_error(x,ptr,size,err) \
193 ({ \
194 __put_user_size((x),(ptr),(size),err); \
195 (void) 0; \
196 })
197
198 extern long __get_user_bad(void);
199
200 #define __get_user_size(x,ptr,size,retval) \
201 do { \
202 switch (size) { \
203 case 1: __get_user_asm_byte(x,ptr,retval); break; \
204 case 2: __get_user_asm_half(x,ptr,retval); break; \
205 case 4: __get_user_asm_word(x,ptr,retval); break; \
206 default: (x) = __get_user_bad(); \
207 } \
208 } while (0)
209
210 extern long __put_user_bad(void);
211
212 #define __put_user_size(x,ptr,size,retval) \
213 do { \
214 switch (size) { \
215 case 1: __put_user_asm_byte(x,ptr,retval); break; \
216 case 2: __put_user_asm_half(x,ptr,retval); break; \
217 case 4: __put_user_asm_word(x,ptr,retval); break; \
218 default: __put_user_bad(); \
219 } \
220 } while (0)
221
222 #endif /* _ASMARM_UACCESS_H */
223