uaccess.h

 1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef UACCESS_H
 3#define UACCESS_H
 4
 5#include <linux/compiler.h>
 6
 7extern void *__user_addr_min, *__user_addr_max;
 8
 9#define put_user(x, ptr)					\
10({								\
11	typeof(ptr) __pu_ptr = (ptr);				\
12	__chk_user_ptr(__pu_ptr);				\
13	WRITE_ONCE(*(__pu_ptr), x);				\
14	0;							\
15})
16
17#define get_user(x, ptr)					\
18({								\
19	typeof(ptr) __pu_ptr = (ptr);				\
20	__chk_user_ptr(__pu_ptr);				\
21	x = READ_ONCE(*(__pu_ptr));				\
22	0;							\
23})
24
25static void volatile_memcpy(volatile char *to, const volatile char *from, 
26			    unsigned long n)
27{
28	while (n--)
29		*(to++) = *(from++);
30}
31
32static inline int copy_from_user(void *to, const void __user volatile *from,
33				 unsigned long n)
34{
35	volatile_memcpy(to, from, n);
36	return 0;
37}
38
39static inline int copy_to_user(void __user volatile *to, const void *from,
40			       unsigned long n)
41{
42	volatile_memcpy(to, from, n);
43	return 0;
44}
45#endif /* UACCESS_H */