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 #include <asm-generic/access_ok.h>
12
13 #ifdef CONFIG_UACCESS_MEMCPY
14 #include <asm/unaligned.h>
15
16 static __always_inline int
17 __get_user_fn(size_t size, const void __user *from, void *to)
18 {
19 BUILD_BUG_ON(!__builtin_constant_p(size));
20
21 switch (size) {
22 case 1:
23 *(u8 *)to = *((u8 __force *)from);
24 return 0;
25 case 2:
26 *(u16 *)to = get_unaligned((u16 __force *)from);
27 return 0;
28 case 4:
29 *(u32 *)to = get_unaligned((u32 __force *)from);
30 return 0;
31 case 8:
32 *(u64 *)to = get_unaligned((u64 __force *)from);
33 return 0;
34 default:
35 BUILD_BUG();
36 return 0;
37 }
38
39 }
40 #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
41
42 static __always_inline int
43 __put_user_fn(size_t size, void __user *to, void *from)
44 {
45 BUILD_BUG_ON(!__builtin_constant_p(size));
46
47 switch (size) {
48 case 1:
49 *(u8 __force *)to = *(u8 *)from;
50 return 0;
51 case 2:
52 put_unaligned(*(u16 *)from, (u16 __force *)to);
53 return 0;
54 case 4:
55 put_unaligned(*(u32 *)from, (u32 __force *)to);
56 return 0;
57 case 8:
58 put_unaligned(*(u64 *)from, (u64 __force *)to);
59 return 0;
60 default:
61 BUILD_BUG();
62 return 0;
63 }
64 }
65 #define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
66
67 #define __get_kernel_nofault(dst, src, type, err_label) \
68 do { \
69 *((type *)dst) = get_unaligned((type *)(src)); \
70 if (0) /* make sure the label looks used to the compiler */ \
71 goto err_label; \
72 } while (0)
73
74 #define __put_kernel_nofault(dst, src, type, err_label) \
75 do { \
76 put_unaligned(*((type *)src), (type *)(dst)); \
77 if (0) /* make sure the label looks used to the compiler */ \
78 goto err_label; \
79 } while (0)
80
81 static inline __must_check unsigned long
82 raw_copy_from_user(void *to, const void __user * from, unsigned long n)
83 {
84 memcpy(to, (const void __force *)from, n);
85 return 0;
86 }
87
88 static inline __must_check unsigned long
89 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
90 {
91 memcpy((void __force *)to, from, n);
92 return 0;
93 }
94 #define INLINE_COPY_FROM_USER
95 #define INLINE_COPY_TO_USER
96 #endif /* CONFIG_UACCESS_MEMCPY */
97
98 /*
99 * These are the main single-value transfer routines. They automatically
100 * use the right size if we just have the right pointer type.
101 * This version just falls back to copy_{from,to}_user, which should
102 * provide a fast-path for small values.
103 */
104 #define __put_user(x, ptr) \
105 ({ \
106 __typeof__(*(ptr)) __x = (x); \
107 int __pu_err = -EFAULT; \
108 __chk_user_ptr(ptr); \
109 switch (sizeof (*(ptr))) { \
110 case 1: \
111 case 2: \
112 case 4: \
113 case 8: \
114 __pu_err = __put_user_fn(sizeof (*(ptr)), \
115 ptr, &__x); \
116 break; \
117 default: \
118 __put_user_bad(); \
119 break; \
120 } \
121 __pu_err; \
122 })
123
124 #define put_user(x, ptr) \
125 ({ \
126 void __user *__p = (ptr); \
127 might_fault(); \
128 access_ok(__p, sizeof(*ptr)) ? \
129 __put_user((x), ((__typeof__(*(ptr)) __user *)__p)) : \
130 -EFAULT; \
131 })
132
133 #ifndef __put_user_fn
134
135 static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
136 {
137 return unlikely(raw_copy_to_user(ptr, x, size)) ? -EFAULT : 0;
138 }
139
140 #define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
141
142 #endif
143
144 extern int __put_user_bad(void) __attribute__((noreturn));
145
146 #define __get_user(x, ptr) \
147 ({ \
148 int __gu_err = -EFAULT; \
149 __chk_user_ptr(ptr); \
150 switch (sizeof(*(ptr))) { \
151 case 1: { \
152 unsigned char __x = 0; \
153 __gu_err = __get_user_fn(sizeof (*(ptr)), \
154 ptr, &__x); \
155 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
156 break; \
157 }; \
158 case 2: { \
159 unsigned short __x = 0; \
160 __gu_err = __get_user_fn(sizeof (*(ptr)), \
161 ptr, &__x); \
162 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
163 break; \
164 }; \
165 case 4: { \
166 unsigned int __x = 0; \
167 __gu_err = __get_user_fn(sizeof (*(ptr)), \
168 ptr, &__x); \
169 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
170 break; \
171 }; \
172 case 8: { \
173 unsigned long long __x = 0; \
174 __gu_err = __get_user_fn(sizeof (*(ptr)), \
175 ptr, &__x); \
176 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
177 break; \
178 }; \
179 default: \
180 __get_user_bad(); \
181 break; \
182 } \
183 __gu_err; \
184 })
185
186 #define get_user(x, ptr) \
187 ({ \
188 const void __user *__p = (ptr); \
189 might_fault(); \
190 access_ok(__p, sizeof(*ptr)) ? \
191 __get_user((x), (__typeof__(*(ptr)) __user *)__p) :\
192 ((x) = (__typeof__(*(ptr)))0,-EFAULT); \
193 })
194
195 #ifndef __get_user_fn
196 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
197 {
198 return unlikely(raw_copy_from_user(x, ptr, size)) ? -EFAULT : 0;
199 }
200
201 #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
202
203 #endif
204
205 extern int __get_user_bad(void) __attribute__((noreturn));
206
207 /*
208 * Zero Userspace
209 */
210 #ifndef __clear_user
211 static inline __must_check unsigned long
212 __clear_user(void __user *to, unsigned long n)
213 {
214 memset((void __force *)to, 0, n);
215 return 0;
216 }
217 #endif
218
219 static inline __must_check unsigned long
220 clear_user(void __user *to, unsigned long n)
221 {
222 might_fault();
223 if (!access_ok(to, n))
224 return n;
225
226 return __clear_user(to, n);
227 }
228
229 #include <asm/extable.h>
230
231 __must_check long strncpy_from_user(char *dst, const char __user *src,
232 long count);
233 __must_check long strnlen_user(const char __user *src, long n);
234
235 #endif /* __ASM_GENERIC_UACCESS_H */
236
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.