Loading...
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#ifndef __ASM_GENERIC_UACCESS_H
2#define __ASM_GENERIC_UACCESS_H
3
4/*
5 * User space memory access functions, these should work
6 * on any machine that has kernel and user data in the same
7 * address space, e.g. all NOMMU machines.
8 */
9#include <linux/sched.h>
10#include <linux/string.h>
11
12#include <asm/segment.h>
13
14#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
15
16#ifndef KERNEL_DS
17#define KERNEL_DS MAKE_MM_SEG(~0UL)
18#endif
19
20#ifndef USER_DS
21#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
22#endif
23
24#ifndef get_fs
25#define get_ds() (KERNEL_DS)
26#define get_fs() (current_thread_info()->addr_limit)
27
28static inline void set_fs(mm_segment_t fs)
29{
30 current_thread_info()->addr_limit = fs;
31}
32#endif
33
34#ifndef segment_eq
35#define segment_eq(a, b) ((a).seg == (b).seg)
36#endif
37
38#define VERIFY_READ 0
39#define VERIFY_WRITE 1
40
41#define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size))
42
43/*
44 * The architecture should really override this if possible, at least
45 * doing a check on the get_fs()
46 */
47#ifndef __access_ok
48static inline int __access_ok(unsigned long addr, unsigned long size)
49{
50 return 1;
51}
52#endif
53
54/*
55 * The exception table consists of pairs of addresses: the first is the
56 * address of an instruction that is allowed to fault, and the second is
57 * the address at which the program should continue. No registers are
58 * modified, so it is entirely up to the continuation code to figure out
59 * what to do.
60 *
61 * All the routines below use bits of fixup code that are out of line
62 * with the main instruction path. This means when everything is well,
63 * we don't even have to jump over them. Further, they do not intrude
64 * on our cache or tlb entries.
65 */
66
67struct exception_table_entry
68{
69 unsigned long insn, fixup;
70};
71
72/* Returns 0 if exception not found and fixup otherwise. */
73extern unsigned long search_exception_table(unsigned long);
74
75/*
76 * architectures with an MMU should override these two
77 */
78#ifndef __copy_from_user
79static inline __must_check long __copy_from_user(void *to,
80 const void __user * from, unsigned long n)
81{
82 if (__builtin_constant_p(n)) {
83 switch(n) {
84 case 1:
85 *(u8 *)to = *(u8 __force *)from;
86 return 0;
87 case 2:
88 *(u16 *)to = *(u16 __force *)from;
89 return 0;
90 case 4:
91 *(u32 *)to = *(u32 __force *)from;
92 return 0;
93#ifdef CONFIG_64BIT
94 case 8:
95 *(u64 *)to = *(u64 __force *)from;
96 return 0;
97#endif
98 default:
99 break;
100 }
101 }
102
103 memcpy(to, (const void __force *)from, n);
104 return 0;
105}
106#endif
107
108#ifndef __copy_to_user
109static inline __must_check long __copy_to_user(void __user *to,
110 const void *from, unsigned long n)
111{
112 if (__builtin_constant_p(n)) {
113 switch(n) {
114 case 1:
115 *(u8 __force *)to = *(u8 *)from;
116 return 0;
117 case 2:
118 *(u16 __force *)to = *(u16 *)from;
119 return 0;
120 case 4:
121 *(u32 __force *)to = *(u32 *)from;
122 return 0;
123#ifdef CONFIG_64BIT
124 case 8:
125 *(u64 __force *)to = *(u64 *)from;
126 return 0;
127#endif
128 default:
129 break;
130 }
131 }
132
133 memcpy((void __force *)to, from, n);
134 return 0;
135}
136#endif
137
138/*
139 * These are the main single-value transfer routines. They automatically
140 * use the right size if we just have the right pointer type.
141 * This version just falls back to copy_{from,to}_user, which should
142 * provide a fast-path for small values.
143 */
144#define __put_user(x, ptr) \
145({ \
146 __typeof__(*(ptr)) __x = (x); \
147 int __pu_err = -EFAULT; \
148 __chk_user_ptr(ptr); \
149 switch (sizeof (*(ptr))) { \
150 case 1: \
151 case 2: \
152 case 4: \
153 case 8: \
154 __pu_err = __put_user_fn(sizeof (*(ptr)), \
155 ptr, &__x); \
156 break; \
157 default: \
158 __put_user_bad(); \
159 break; \
160 } \
161 __pu_err; \
162})
163
164#define put_user(x, ptr) \
165({ \
166 void *__p = (ptr); \
167 might_fault(); \
168 access_ok(VERIFY_WRITE, __p, sizeof(*ptr)) ? \
169 __put_user((x), ((__typeof__(*(ptr)) *)__p)) : \
170 -EFAULT; \
171})
172
173#ifndef __put_user_fn
174
175static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
176{
177 size = __copy_to_user(ptr, x, size);
178 return size ? -EFAULT : size;
179}
180
181#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
182
183#endif
184
185extern int __put_user_bad(void) __attribute__((noreturn));
186
187#define __get_user(x, ptr) \
188({ \
189 int __gu_err = -EFAULT; \
190 __chk_user_ptr(ptr); \
191 switch (sizeof(*(ptr))) { \
192 case 1: { \
193 unsigned char __x; \
194 __gu_err = __get_user_fn(sizeof (*(ptr)), \
195 ptr, &__x); \
196 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
197 break; \
198 }; \
199 case 2: { \
200 unsigned short __x; \
201 __gu_err = __get_user_fn(sizeof (*(ptr)), \
202 ptr, &__x); \
203 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
204 break; \
205 }; \
206 case 4: { \
207 unsigned int __x; \
208 __gu_err = __get_user_fn(sizeof (*(ptr)), \
209 ptr, &__x); \
210 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
211 break; \
212 }; \
213 case 8: { \
214 unsigned long long __x; \
215 __gu_err = __get_user_fn(sizeof (*(ptr)), \
216 ptr, &__x); \
217 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
218 break; \
219 }; \
220 default: \
221 __get_user_bad(); \
222 break; \
223 } \
224 __gu_err; \
225})
226
227#define get_user(x, ptr) \
228({ \
229 const void *__p = (ptr); \
230 might_fault(); \
231 access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \
232 __get_user((x), (__typeof__(*(ptr)) *)__p) : \
233 -EFAULT; \
234})
235
236#ifndef __get_user_fn
237static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
238{
239 size = __copy_from_user(x, ptr, size);
240 return size ? -EFAULT : size;
241}
242
243#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
244
245#endif
246
247extern int __get_user_bad(void) __attribute__((noreturn));
248
249#ifndef __copy_from_user_inatomic
250#define __copy_from_user_inatomic __copy_from_user
251#endif
252
253#ifndef __copy_to_user_inatomic
254#define __copy_to_user_inatomic __copy_to_user
255#endif
256
257static inline long copy_from_user(void *to,
258 const void __user * from, unsigned long n)
259{
260 might_fault();
261 if (access_ok(VERIFY_READ, from, n))
262 return __copy_from_user(to, from, n);
263 else
264 return n;
265}
266
267static inline long copy_to_user(void __user *to,
268 const void *from, unsigned long n)
269{
270 might_fault();
271 if (access_ok(VERIFY_WRITE, to, n))
272 return __copy_to_user(to, from, n);
273 else
274 return n;
275}
276
277/*
278 * Copy a null terminated string from userspace.
279 */
280#ifndef __strncpy_from_user
281static inline long
282__strncpy_from_user(char *dst, const char __user *src, long count)
283{
284 char *tmp;
285 strncpy(dst, (const char __force *)src, count);
286 for (tmp = dst; *tmp && count > 0; tmp++, count--)
287 ;
288 return (tmp - dst);
289}
290#endif
291
292static inline long
293strncpy_from_user(char *dst, const char __user *src, long count)
294{
295 if (!access_ok(VERIFY_READ, src, 1))
296 return -EFAULT;
297 return __strncpy_from_user(dst, src, count);
298}
299
300/*
301 * Return the size of a string (including the ending 0)
302 *
303 * Return 0 on exception, a value greater than N if too long
304 */
305#ifndef __strnlen_user
306#define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
307#endif
308
309/*
310 * Unlike strnlen, strnlen_user includes the nul terminator in
311 * its returned count. Callers should check for a returned value
312 * greater than N as an indication the string is too long.
313 */
314static inline long strnlen_user(const char __user *src, long n)
315{
316 if (!access_ok(VERIFY_READ, src, 1))
317 return 0;
318 return __strnlen_user(src, n);
319}
320
321static inline long strlen_user(const char __user *src)
322{
323 return strnlen_user(src, 32767);
324}
325
326/*
327 * Zero Userspace
328 */
329#ifndef __clear_user
330static inline __must_check unsigned long
331__clear_user(void __user *to, unsigned long n)
332{
333 memset((void __force *)to, 0, n);
334 return 0;
335}
336#endif
337
338static inline __must_check unsigned long
339clear_user(void __user *to, unsigned long n)
340{
341 might_fault();
342 if (!access_ok(VERIFY_WRITE, to, n))
343 return n;
344
345 return __clear_user(to, n);
346}
347
348#endif /* __ASM_GENERIC_UACCESS_H */