1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ASM_GENERIC_UACCESS_H
3 #define __ASM_GENERIC_UACCESS_H
4
5 /*
6 * User space memory access functions, these should work
7 * on any machine that has kernel and user data in the same
8 * address space, e.g. all NOMMU machines.
9 */
10 #include <linux/string.h>
11
12 #ifdef CONFIG_UACCESS_MEMCPY
13 static inline __must_check unsigned long
raw_copy_from_user(void * to,const void __user * from,unsigned long n)14 raw_copy_from_user(void *to, const void __user * from, unsigned long n)
15 {
16 if (__builtin_constant_p(n)) {
17 switch(n) {
18 case 1:
19 *(u8 *)to = *(u8 __force *)from;
20 return 0;
21 case 2:
22 *(u16 *)to = *(u16 __force *)from;
23 return 0;
24 case 4:
25 *(u32 *)to = *(u32 __force *)from;
26 return 0;
27 #ifdef CONFIG_64BIT
28 case 8:
29 *(u64 *)to = *(u64 __force *)from;
30 return 0;
31 #endif
32 }
33 }
34
35 memcpy(to, (const void __force *)from, n);
36 return 0;
37 }
38
39 static inline __must_check unsigned long
raw_copy_to_user(void __user * to,const void * from,unsigned long n)40 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
41 {
42 if (__builtin_constant_p(n)) {
43 switch(n) {
44 case 1:
45 *(u8 __force *)to = *(u8 *)from;
46 return 0;
47 case 2:
48 *(u16 __force *)to = *(u16 *)from;
49 return 0;
50 case 4:
51 *(u32 __force *)to = *(u32 *)from;
52 return 0;
53 #ifdef CONFIG_64BIT
54 case 8:
55 *(u64 __force *)to = *(u64 *)from;
56 return 0;
57 #endif
58 default:
59 break;
60 }
61 }
62
63 memcpy((void __force *)to, from, n);
64 return 0;
65 }
66 #define INLINE_COPY_FROM_USER
67 #define INLINE_COPY_TO_USER
68 #endif /* CONFIG_UACCESS_MEMCPY */
69
70 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
71
72 #ifndef KERNEL_DS
73 #define KERNEL_DS MAKE_MM_SEG(~0UL)
74 #endif
75
76 #ifndef USER_DS
77 #define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
78 #endif
79
80 #ifndef get_fs
81 #define get_fs() (current_thread_info()->addr_limit)
82
set_fs(mm_segment_t fs)83 static inline void set_fs(mm_segment_t fs)
84 {
85 current_thread_info()->addr_limit = fs;
86 }
87 #endif
88
89 #ifndef segment_eq
90 #define segment_eq(a, b) ((a).seg == (b).seg)
91 #endif
92
93 #define access_ok(addr, size) __access_ok((unsigned long)(addr),(size))
94
95 /*
96 * The architecture should really override this if possible, at least
97 * doing a check on the get_fs()
98 */
99 #ifndef __access_ok
__access_ok(unsigned long addr,unsigned long size)100 static inline int __access_ok(unsigned long addr, unsigned long size)
101 {
102 return 1;
103 }
104 #endif
105
106 /*
107 * These are the main single-value transfer routines. They automatically
108 * use the right size if we just have the right pointer type.
109 * This version just falls back to copy_{from,to}_user, which should
110 * provide a fast-path for small values.
111 */
112 #define __put_user(x, ptr) \
113 ({ \
114 __typeof__(*(ptr)) __x = (x); \
115 int __pu_err = -EFAULT; \
116 __chk_user_ptr(ptr); \
117 switch (sizeof (*(ptr))) { \
118 case 1: \
119 case 2: \
120 case 4: \
121 case 8: \
122 __pu_err = __put_user_fn(sizeof (*(ptr)), \
123 ptr, &__x); \
124 break; \
125 default: \
126 __put_user_bad(); \
127 break; \
128 } \
129 __pu_err; \
130 })
131
132 #define put_user(x, ptr) \
133 ({ \
134 void __user *__p = (ptr); \
135 might_fault(); \
136 access_ok(__p, sizeof(*ptr)) ? \
137 __put_user((x), ((__typeof__(*(ptr)) __user *)__p)) : \
138 -EFAULT; \
139 })
140
141 #ifndef __put_user_fn
142
__put_user_fn(size_t size,void __user * ptr,void * x)143 static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
144 {
145 return unlikely(raw_copy_to_user(ptr, x, size)) ? -EFAULT : 0;
146 }
147
148 #define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
149
150 #endif
151
152 extern int __put_user_bad(void) __attribute__((noreturn));
153
154 #define __get_user(x, ptr) \
155 ({ \
156 int __gu_err = -EFAULT; \
157 __chk_user_ptr(ptr); \
158 switch (sizeof(*(ptr))) { \
159 case 1: { \
160 unsigned char __x = 0; \
161 __gu_err = __get_user_fn(sizeof (*(ptr)), \
162 ptr, &__x); \
163 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
164 break; \
165 }; \
166 case 2: { \
167 unsigned short __x = 0; \
168 __gu_err = __get_user_fn(sizeof (*(ptr)), \
169 ptr, &__x); \
170 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
171 break; \
172 }; \
173 case 4: { \
174 unsigned int __x = 0; \
175 __gu_err = __get_user_fn(sizeof (*(ptr)), \
176 ptr, &__x); \
177 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
178 break; \
179 }; \
180 case 8: { \
181 unsigned long long __x = 0; \
182 __gu_err = __get_user_fn(sizeof (*(ptr)), \
183 ptr, &__x); \
184 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
185 break; \
186 }; \
187 default: \
188 __get_user_bad(); \
189 break; \
190 } \
191 __gu_err; \
192 })
193
194 #define get_user(x, ptr) \
195 ({ \
196 const void __user *__p = (ptr); \
197 might_fault(); \
198 access_ok(__p, sizeof(*ptr)) ? \
199 __get_user((x), (__typeof__(*(ptr)) __user *)__p) :\
200 ((x) = (__typeof__(*(ptr)))0,-EFAULT); \
201 })
202
203 #ifndef __get_user_fn
__get_user_fn(size_t size,const void __user * ptr,void * x)204 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
205 {
206 return unlikely(raw_copy_from_user(x, ptr, size)) ? -EFAULT : 0;
207 }
208
209 #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
210
211 #endif
212
213 extern int __get_user_bad(void) __attribute__((noreturn));
214
215 /*
216 * Copy a null terminated string from userspace.
217 */
218 #ifndef __strncpy_from_user
219 static inline long
__strncpy_from_user(char * dst,const char __user * src,long count)220 __strncpy_from_user(char *dst, const char __user *src, long count)
221 {
222 char *tmp;
223 strncpy(dst, (const char __force *)src, count);
224 for (tmp = dst; *tmp && count > 0; tmp++, count--)
225 ;
226 return (tmp - dst);
227 }
228 #endif
229
230 static inline long
strncpy_from_user(char * dst,const char __user * src,long count)231 strncpy_from_user(char *dst, const char __user *src, long count)
232 {
233 if (!access_ok(src, 1))
234 return -EFAULT;
235 return __strncpy_from_user(dst, src, count);
236 }
237
238 /*
239 * Return the size of a string (including the ending 0)
240 *
241 * Return 0 on exception, a value greater than N if too long
242 */
243 #ifndef __strnlen_user
244 #define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
245 #endif
246
247 /*
248 * Unlike strnlen, strnlen_user includes the nul terminator in
249 * its returned count. Callers should check for a returned value
250 * greater than N as an indication the string is too long.
251 */
strnlen_user(const char __user * src,long n)252 static inline long strnlen_user(const char __user *src, long n)
253 {
254 if (!access_ok(src, 1))
255 return 0;
256 return __strnlen_user(src, n);
257 }
258
259 /*
260 * Zero Userspace
261 */
262 #ifndef __clear_user
263 static inline __must_check unsigned long
__clear_user(void __user * to,unsigned long n)264 __clear_user(void __user *to, unsigned long n)
265 {
266 memset((void __force *)to, 0, n);
267 return 0;
268 }
269 #endif
270
271 static inline __must_check unsigned long
clear_user(void __user * to,unsigned long n)272 clear_user(void __user *to, unsigned long n)
273 {
274 might_fault();
275 if (!access_ok(to, n))
276 return n;
277
278 return __clear_user(to, n);
279 }
280
281 #include <asm/extable.h>
282
283 #endif /* __ASM_GENERIC_UACCESS_H */
284
