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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
13static inline __must_check unsigned long
14raw_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
39static inline __must_check unsigned long
40raw_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
83static 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
100static 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
143static 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
152extern 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
204static 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
213extern int __get_user_bad(void) __attribute__((noreturn));
214
215/*
216 * Copy a null terminated string from userspace.
217 */
218#ifndef __strncpy_from_user
219static inline long
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
230static inline long
231strncpy_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 */
252static 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
263static inline __must_check unsigned long
264__clear_user(void __user *to, unsigned long n)
265{
266 memset((void __force *)to, 0, n);
267 return 0;
268}
269#endif
270
271static inline __must_check unsigned long
272clear_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 */
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
16static __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
42static __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) \
68do { \
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) \
75do { \
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
81static inline __must_check unsigned long
82raw_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
88static inline __must_check unsigned long
89raw_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
135static 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
144extern 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
196static 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
205extern int __get_user_bad(void) __attribute__((noreturn));
206
207/*
208 * Zero Userspace
209 */
210#ifndef __clear_user
211static 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
219static inline __must_check unsigned long
220clear_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 */