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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
12#ifdef CONFIG_UACCESS_MEMCPY
13#include <asm/unaligned.h>
14
15static __always_inline int
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
41static __always_inline int
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) \
67do { \
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) \
74do { \
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
82static inline __must_check unsigned long
83raw_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
89static inline __must_check unsigned long
90raw_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
113static 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#endif /* CONFIG_SET_FS */
123
124#define access_ok(addr, size) __access_ok((unsigned long)(addr),(size))
125
126/*
127 * The architecture should really override this if possible, at least
128 * doing a check on the get_fs()
129 */
130#ifndef __access_ok
131static inline int __access_ok(unsigned long addr, unsigned long size)
132{
133 return 1;
134}
135#endif
136
137/*
138 * These are the main single-value transfer routines. They automatically
139 * use the right size if we just have the right pointer type.
140 * This version just falls back to copy_{from,to}_user, which should
141 * provide a fast-path for small values.
142 */
143#define __put_user(x, ptr) \
144({ \
145 __typeof__(*(ptr)) __x = (x); \
146 int __pu_err = -EFAULT; \
147 __chk_user_ptr(ptr); \
148 switch (sizeof (*(ptr))) { \
149 case 1: \
150 case 2: \
151 case 4: \
152 case 8: \
153 __pu_err = __put_user_fn(sizeof (*(ptr)), \
154 ptr, &__x); \
155 break; \
156 default: \
157 __put_user_bad(); \
158 break; \
159 } \
160 __pu_err; \
161})
162
163#define put_user(x, ptr) \
164({ \
165 void __user *__p = (ptr); \
166 might_fault(); \
167 access_ok(__p, sizeof(*ptr)) ? \
168 __put_user((x), ((__typeof__(*(ptr)) __user *)__p)) : \
169 -EFAULT; \
170})
171
172#ifndef __put_user_fn
173
174static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
175{
176 return unlikely(raw_copy_to_user(ptr, x, size)) ? -EFAULT : 0;
177}
178
179#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
180
181#endif
182
183extern int __put_user_bad(void) __attribute__((noreturn));
184
185#define __get_user(x, ptr) \
186({ \
187 int __gu_err = -EFAULT; \
188 __chk_user_ptr(ptr); \
189 switch (sizeof(*(ptr))) { \
190 case 1: { \
191 unsigned char __x = 0; \
192 __gu_err = __get_user_fn(sizeof (*(ptr)), \
193 ptr, &__x); \
194 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
195 break; \
196 }; \
197 case 2: { \
198 unsigned short __x = 0; \
199 __gu_err = __get_user_fn(sizeof (*(ptr)), \
200 ptr, &__x); \
201 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
202 break; \
203 }; \
204 case 4: { \
205 unsigned int __x = 0; \
206 __gu_err = __get_user_fn(sizeof (*(ptr)), \
207 ptr, &__x); \
208 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
209 break; \
210 }; \
211 case 8: { \
212 unsigned long long __x = 0; \
213 __gu_err = __get_user_fn(sizeof (*(ptr)), \
214 ptr, &__x); \
215 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
216 break; \
217 }; \
218 default: \
219 __get_user_bad(); \
220 break; \
221 } \
222 __gu_err; \
223})
224
225#define get_user(x, ptr) \
226({ \
227 const void __user *__p = (ptr); \
228 might_fault(); \
229 access_ok(__p, sizeof(*ptr)) ? \
230 __get_user((x), (__typeof__(*(ptr)) __user *)__p) :\
231 ((x) = (__typeof__(*(ptr)))0,-EFAULT); \
232})
233
234#ifndef __get_user_fn
235static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
236{
237 return unlikely(raw_copy_from_user(x, ptr, size)) ? -EFAULT : 0;
238}
239
240#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
241
242#endif
243
244extern int __get_user_bad(void) __attribute__((noreturn));
245
246/*
247 * Copy a null terminated string from userspace.
248 */
249#ifndef __strncpy_from_user
250static inline long
251__strncpy_from_user(char *dst, const char __user *src, long count)
252{
253 char *tmp;
254 strncpy(dst, (const char __force *)src, count);
255 for (tmp = dst; *tmp && count > 0; tmp++, count--)
256 ;
257 return (tmp - dst);
258}
259#endif
260
261static inline long
262strncpy_from_user(char *dst, const char __user *src, long count)
263{
264 if (!access_ok(src, 1))
265 return -EFAULT;
266 return __strncpy_from_user(dst, src, count);
267}
268
269/*
270 * Return the size of a string (including the ending 0)
271 *
272 * Return 0 on exception, a value greater than N if too long
273 */
274#ifndef __strnlen_user
275#define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
276#endif
277
278/*
279 * Unlike strnlen, strnlen_user includes the nul terminator in
280 * its returned count. Callers should check for a returned value
281 * greater than N as an indication the string is too long.
282 */
283static inline long strnlen_user(const char __user *src, long n)
284{
285 if (!access_ok(src, 1))
286 return 0;
287 return __strnlen_user(src, n);
288}
289
290/*
291 * Zero Userspace
292 */
293#ifndef __clear_user
294static inline __must_check unsigned long
295__clear_user(void __user *to, unsigned long n)
296{
297 memset((void __force *)to, 0, n);
298 return 0;
299}
300#endif
301
302static inline __must_check unsigned long
303clear_user(void __user *to, unsigned long n)
304{
305 might_fault();
306 if (!access_ok(to, n))
307 return n;
308
309 return __clear_user(to, n);
310}
311
312#include <asm/extable.h>
313
314#endif /* __ASM_GENERIC_UACCESS_H */