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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#include <asm-generic/access_ok.h>
12
13#ifdef CONFIG_UACCESS_MEMCPY
14#include <linux/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_USER
95#endif /* CONFIG_UACCESS_MEMCPY */
96
97/*
98 * These are the main single-value transfer routines. They automatically
99 * use the right size if we just have the right pointer type.
100 * This version just falls back to copy_{from,to}_user, which should
101 * provide a fast-path for small values.
102 */
103#define __put_user(x, ptr) \
104({ \
105 __typeof__(*(ptr)) __x = (x); \
106 int __pu_err = -EFAULT; \
107 __chk_user_ptr(ptr); \
108 switch (sizeof (*(ptr))) { \
109 case 1: \
110 case 2: \
111 case 4: \
112 case 8: \
113 __pu_err = __put_user_fn(sizeof (*(ptr)), \
114 ptr, &__x); \
115 break; \
116 default: \
117 __put_user_bad(); \
118 break; \
119 } \
120 __pu_err; \
121})
122
123#define put_user(x, ptr) \
124({ \
125 void __user *__p = (ptr); \
126 might_fault(); \
127 access_ok(__p, sizeof(*ptr)) ? \
128 __put_user((x), ((__typeof__(*(ptr)) __user *)__p)) : \
129 -EFAULT; \
130})
131
132#ifndef __put_user_fn
133
134static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
135{
136 return unlikely(raw_copy_to_user(ptr, x, size)) ? -EFAULT : 0;
137}
138
139#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
140
141#endif
142
143extern int __put_user_bad(void) __attribute__((noreturn));
144
145#define __get_user(x, ptr) \
146({ \
147 int __gu_err = -EFAULT; \
148 __chk_user_ptr(ptr); \
149 switch (sizeof(*(ptr))) { \
150 case 1: { \
151 unsigned char __x = 0; \
152 __gu_err = __get_user_fn(sizeof (*(ptr)), \
153 ptr, &__x); \
154 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
155 break; \
156 }; \
157 case 2: { \
158 unsigned short __x = 0; \
159 __gu_err = __get_user_fn(sizeof (*(ptr)), \
160 ptr, &__x); \
161 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
162 break; \
163 }; \
164 case 4: { \
165 unsigned int __x = 0; \
166 __gu_err = __get_user_fn(sizeof (*(ptr)), \
167 ptr, &__x); \
168 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
169 break; \
170 }; \
171 case 8: { \
172 unsigned long long __x = 0; \
173 __gu_err = __get_user_fn(sizeof (*(ptr)), \
174 ptr, &__x); \
175 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
176 break; \
177 }; \
178 default: \
179 __get_user_bad(); \
180 break; \
181 } \
182 __gu_err; \
183})
184
185#define get_user(x, ptr) \
186({ \
187 const void __user *__p = (ptr); \
188 might_fault(); \
189 access_ok(__p, sizeof(*ptr)) ? \
190 __get_user((x), (__typeof__(*(ptr)) __user *)__p) :\
191 ((x) = (__typeof__(*(ptr)))0,-EFAULT); \
192})
193
194#ifndef __get_user_fn
195static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
196{
197 return unlikely(raw_copy_from_user(x, ptr, size)) ? -EFAULT : 0;
198}
199
200#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
201
202#endif
203
204extern int __get_user_bad(void) __attribute__((noreturn));
205
206/*
207 * Zero Userspace
208 */
209#ifndef __clear_user
210static inline __must_check unsigned long
211__clear_user(void __user *to, unsigned long n)
212{
213 memset((void __force *)to, 0, n);
214 return 0;
215}
216#endif
217
218static inline __must_check unsigned long
219clear_user(void __user *to, unsigned long n)
220{
221 might_fault();
222 if (!access_ok(to, n))
223 return n;
224
225 return __clear_user(to, n);
226}
227
228#include <asm/extable.h>
229
230__must_check long strncpy_from_user(char *dst, const char __user *src,
231 long count);
232__must_check long strnlen_user(const char __user *src, long n);
233
234#endif /* __ASM_GENERIC_UACCESS_H */