1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
4 *
5 * Derived from MIPS:
6 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
7 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
8 * Copyright (C) 2007 Maciej W. Rozycki
9 * Copyright (C) 2014, Imagination Technologies Ltd.
10 */
11 #ifndef _ASM_UACCESS_H
12 #define _ASM_UACCESS_H
13
14 #include <linux/kernel.h>
15 #include <linux/string.h>
16 #include <linux/extable.h>
17 #include <asm/pgtable.h>
18 #include <asm/extable.h>
19 #include <asm/asm-extable.h>
20 #include <asm-generic/access_ok.h>
21
22 extern u64 __ua_limit;
23
24 #define __UA_ADDR ".dword"
25 #define __UA_LIMIT __ua_limit
26
27 /*
28 * get_user: - Get a simple variable from user space.
29 * @x: Variable to store result.
30 * @ptr: Source address, in user space.
31 *
32 * Context: User context only. This function may sleep if pagefaults are
33 * enabled.
34 *
35 * This macro copies a single simple variable from user space to kernel
36 * space. It supports simple types like char and int, but not larger
37 * data types like structures or arrays.
38 *
39 * @ptr must have pointer-to-simple-variable type, and the result of
40 * dereferencing @ptr must be assignable to @x without a cast.
41 *
42 * Returns zero on success, or -EFAULT on error.
43 * On error, the variable @x is set to zero.
44 */
45 #define get_user(x, ptr) \
46 ({ \
47 const __typeof__(*(ptr)) __user *__p = (ptr); \
48 \
49 might_fault(); \
50 access_ok(__p, sizeof(*__p)) ? __get_user((x), __p) : \
51 ((x) = 0, -EFAULT); \
52 })
53
54 /*
55 * put_user: - Write a simple value into user space.
56 * @x: Value to copy to user space.
57 * @ptr: Destination address, in user space.
58 *
59 * Context: User context only. This function may sleep if pagefaults are
60 * enabled.
61 *
62 * This macro copies a single simple value from kernel space to user
63 * space. It supports simple types like char and int, but not larger
64 * data types like structures or arrays.
65 *
66 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
67 * to the result of dereferencing @ptr.
68 *
69 * Returns zero on success, or -EFAULT on error.
70 */
71 #define put_user(x, ptr) \
72 ({ \
73 __typeof__(*(ptr)) __user *__p = (ptr); \
74 \
75 might_fault(); \
76 access_ok(__p, sizeof(*__p)) ? __put_user((x), __p) : -EFAULT; \
77 })
78
79 /*
80 * __get_user: - Get a simple variable from user space, with less checking.
81 * @x: Variable to store result.
82 * @ptr: Source address, in user space.
83 *
84 * Context: User context only. This function may sleep if pagefaults are
85 * enabled.
86 *
87 * This macro copies a single simple variable from user space to kernel
88 * space. It supports simple types like char and int, but not larger
89 * data types like structures or arrays.
90 *
91 * @ptr must have pointer-to-simple-variable type, and the result of
92 * dereferencing @ptr must be assignable to @x without a cast.
93 *
94 * Caller must check the pointer with access_ok() before calling this
95 * function.
96 *
97 * Returns zero on success, or -EFAULT on error.
98 * On error, the variable @x is set to zero.
99 */
100 #define __get_user(x, ptr) \
101 ({ \
102 int __gu_err = 0; \
103 \
104 __chk_user_ptr(ptr); \
105 __get_user_common((x), sizeof(*(ptr)), ptr); \
106 __gu_err; \
107 })
108
109 /*
110 * __put_user: - Write a simple value into user space, with less checking.
111 * @x: Value to copy to user space.
112 * @ptr: Destination address, in user space.
113 *
114 * Context: User context only. This function may sleep if pagefaults are
115 * enabled.
116 *
117 * This macro copies a single simple value from kernel space to user
118 * space. It supports simple types like char and int, but not larger
119 * data types like structures or arrays.
120 *
121 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
122 * to the result of dereferencing @ptr.
123 *
124 * Caller must check the pointer with access_ok() before calling this
125 * function.
126 *
127 * Returns zero on success, or -EFAULT on error.
128 */
129 #define __put_user(x, ptr) \
130 ({ \
131 int __pu_err = 0; \
132 __typeof__(*(ptr)) __pu_val; \
133 \
134 __pu_val = (x); \
135 __chk_user_ptr(ptr); \
136 __put_user_common(ptr, sizeof(*(ptr))); \
137 __pu_err; \
138 })
139
140 struct __large_struct { unsigned long buf[100]; };
141 #define __m(x) (*(struct __large_struct __user *)(x))
142
143 #define __get_user_common(val, size, ptr) \
144 do { \
145 switch (size) { \
146 case 1: __get_data_asm(val, "ld.b", ptr); break; \
147 case 2: __get_data_asm(val, "ld.h", ptr); break; \
148 case 4: __get_data_asm(val, "ld.w", ptr); break; \
149 case 8: __get_data_asm(val, "ld.d", ptr); break; \
150 default: BUILD_BUG(); break; \
151 } \
152 } while (0)
153
154 #define __get_kernel_common(val, size, ptr) __get_user_common(val, size, ptr)
155
156 #define __get_data_asm(val, insn, ptr) \
157 { \
158 long __gu_tmp; \
159 \
160 __asm__ __volatile__( \
161 "1: " insn " %1, %2 \n" \
162 "2: \n" \
163 _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %0, %1) \
164 : "+r" (__gu_err), "=r" (__gu_tmp) \
165 : "m" (__m(ptr))); \
166 \
167 (val) = (__typeof__(*(ptr))) __gu_tmp; \
168 }
169
170 #define __put_user_common(ptr, size) \
171 do { \
172 switch (size) { \
173 case 1: __put_data_asm("st.b", ptr); break; \
174 case 2: __put_data_asm("st.h", ptr); break; \
175 case 4: __put_data_asm("st.w", ptr); break; \
176 case 8: __put_data_asm("st.d", ptr); break; \
177 default: BUILD_BUG(); break; \
178 } \
179 } while (0)
180
181 #define __put_kernel_common(ptr, size) __put_user_common(ptr, size)
182
183 #define __put_data_asm(insn, ptr) \
184 { \
185 __asm__ __volatile__( \
186 "1: " insn " %z2, %1 # __put_user_asm\n" \
187 "2: \n" \
188 _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %0) \
189 : "+r" (__pu_err), "=m" (__m(ptr)) \
190 : "Jr" (__pu_val)); \
191 }
192
193 #define __get_kernel_nofault(dst, src, type, err_label) \
194 do { \
195 int __gu_err = 0; \
196 \
197 __get_kernel_common(*((type *)(dst)), sizeof(type), \
198 (__force type *)(src)); \
199 if (unlikely(__gu_err)) \
200 goto err_label; \
201 } while (0)
202
203 #define __put_kernel_nofault(dst, src, type, err_label) \
204 do { \
205 type __pu_val; \
206 int __pu_err = 0; \
207 \
208 __pu_val = *(__force type *)(src); \
209 __put_kernel_common(((type *)(dst)), sizeof(type)); \
210 if (unlikely(__pu_err)) \
211 goto err_label; \
212 } while (0)
213
214 extern unsigned long __copy_user(void *to, const void *from, __kernel_size_t n);
215
216 static inline unsigned long __must_check
217 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
218 {
219 return __copy_user(to, (__force const void *)from, n);
220 }
221
222 static inline unsigned long __must_check
223 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
224 {
225 return __copy_user((__force void *)to, from, n);
226 }
227
228 #define INLINE_COPY_FROM_USER
229 #define INLINE_COPY_TO_USER
230
231 /*
232 * __clear_user: - Zero a block of memory in user space, with less checking.
233 * @addr: Destination address, in user space.
234 * @size: Number of bytes to zero.
235 *
236 * Zero a block of memory in user space. Caller must check
237 * the specified block with access_ok() before calling this function.
238 *
239 * Returns number of bytes that could not be cleared.
240 * On success, this will be zero.
241 */
242 extern unsigned long __clear_user(void __user *addr, __kernel_size_t size);
243
244 #define clear_user(addr, n) \
245 ({ \
246 void __user *__cl_addr = (addr); \
247 unsigned long __cl_size = (n); \
248 if (__cl_size && access_ok(__cl_addr, __cl_size)) \
249 __cl_size = __clear_user(__cl_addr, __cl_size); \
250 __cl_size; \
251 })
252
253 extern long strncpy_from_user(char *to, const char __user *from, long n);
254 extern long strnlen_user(const char __user *str, long n);
255
256 #endif /* _ASM_UACCESS_H */
257
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