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