1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ASM_GENERIC_UACCESS_H
3 #define __ASM_GENERIC_UACCESS_H
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.
10 #include <linux/string.h>
12 #ifdef CONFIG_UACCESS_MEMCPY
13 static inline __must_check unsigned long
14 raw_copy_from_user(void *to, const void __user * from, unsigned long n)
16 if (__builtin_constant_p(n)) {
19 *(u8 *)to = *(u8 __force *)from;
22 *(u16 *)to = *(u16 __force *)from;
25 *(u32 *)to = *(u32 __force *)from;
29 *(u64 *)to = *(u64 __force *)from;
35 memcpy(to, (const void __force *)from, n);
39 static inline __must_check unsigned long
40 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
42 if (__builtin_constant_p(n)) {
45 *(u8 __force *)to = *(u8 *)from;
48 *(u16 __force *)to = *(u16 *)from;
51 *(u32 __force *)to = *(u32 *)from;
55 *(u64 __force *)to = *(u64 *)from;
63 memcpy((void __force *)to, from, n);
66 #define INLINE_COPY_FROM_USER
67 #define INLINE_COPY_TO_USER
68 #endif /* CONFIG_UACCESS_MEMCPY */
70 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
73 #define KERNEL_DS MAKE_MM_SEG(~0UL)
77 #define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
81 #define get_fs() (current_thread_info()->addr_limit)
83 static inline void set_fs(mm_segment_t fs)
85 current_thread_info()->addr_limit = fs;
90 #define segment_eq(a, b) ((a).seg == (b).seg)
93 #define access_ok(addr, size) __access_ok((unsigned long)(addr),(size))
96 * The architecture should really override this if possible, at least
97 * doing a check on the get_fs()
100 static inline int __access_ok(unsigned long addr, unsigned long size)
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.
112 #define __put_user(x, ptr) \
114 __typeof__(*(ptr)) __x = (x); \
115 int __pu_err = -EFAULT; \
116 __chk_user_ptr(ptr); \
117 switch (sizeof (*(ptr))) { \
122 __pu_err = __put_user_fn(sizeof (*(ptr)), \
132 #define put_user(x, ptr) \
134 void __user *__p = (ptr); \
136 access_ok(__p, sizeof(*ptr)) ? \
137 __put_user((x), ((__typeof__(*(ptr)) __user *)__p)) : \
141 #ifndef __put_user_fn
143 static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
145 return unlikely(raw_copy_to_user(ptr, x, size)) ? -EFAULT : 0;
148 #define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
152 extern int __put_user_bad(void) __attribute__((noreturn));
154 #define __get_user(x, ptr) \
156 int __gu_err = -EFAULT; \
157 __chk_user_ptr(ptr); \
158 switch (sizeof(*(ptr))) { \
160 unsigned char __x = 0; \
161 __gu_err = __get_user_fn(sizeof (*(ptr)), \
163 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
167 unsigned short __x = 0; \
168 __gu_err = __get_user_fn(sizeof (*(ptr)), \
170 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
174 unsigned int __x = 0; \
175 __gu_err = __get_user_fn(sizeof (*(ptr)), \
177 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
181 unsigned long long __x = 0; \
182 __gu_err = __get_user_fn(sizeof (*(ptr)), \
184 (x) = *(__force __typeof__(*(ptr)) *) &__x; \
194 #define get_user(x, ptr) \
196 const void __user *__p = (ptr); \
198 access_ok(__p, sizeof(*ptr)) ? \
199 __get_user((x), (__typeof__(*(ptr)) __user *)__p) :\
200 ((x) = (__typeof__(*(ptr)))0,-EFAULT); \
203 #ifndef __get_user_fn
204 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
206 return unlikely(raw_copy_from_user(x, ptr, size)) ? -EFAULT : 0;
209 #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
213 extern int __get_user_bad(void) __attribute__((noreturn));
216 * Copy a null terminated string from userspace.
218 #ifndef __strncpy_from_user
220 __strncpy_from_user(char *dst, const char __user *src, long count)
223 strncpy(dst, (const char __force *)src, count);
224 for (tmp = dst; *tmp && count > 0; tmp++, count--)
231 strncpy_from_user(char *dst, const char __user *src, long count)
233 if (!access_ok(src, 1))
235 return __strncpy_from_user(dst, src, count);
239 * Return the size of a string (including the ending 0)
241 * Return 0 on exception, a value greater than N if too long
243 #ifndef __strnlen_user
244 #define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
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.
252 static inline long strnlen_user(const char __user *src, long n)
254 if (!access_ok(src, 1))
256 return __strnlen_user(src, n);
263 static inline __must_check unsigned long
264 __clear_user(void __user *to, unsigned long n)
266 memset((void __force *)to, 0, n);
271 static inline __must_check unsigned long
272 clear_user(void __user *to, unsigned long n)
275 if (!access_ok(to, n))
278 return __clear_user(to, n);
281 #include <asm/extable.h>
283 #endif /* __ASM_GENERIC_UACCESS_H */