1#ifndef UACCESS_H
2#define UACCESS_H
3extern void *__user_addr_min, *__user_addr_max;
4
5#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
6
7static inline void __chk_user_ptr(const volatile void *p, size_t size)
8{
9	assert(p >= __user_addr_min && p + size <= __user_addr_max);
10}
11
12#define put_user(x, ptr)					\
13({								\
14	typeof(ptr) __pu_ptr = (ptr);				\
15	__chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr));		\
16	ACCESS_ONCE(*(__pu_ptr)) = x;				\
17	0;							\
18})
19
20#define get_user(x, ptr)					\
21({								\
22	typeof(ptr) __pu_ptr = (ptr);				\
23	__chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr));		\
24	x = ACCESS_ONCE(*(__pu_ptr));				\
25	0;							\
26})
27
28static void volatile_memcpy(volatile char *to, const volatile char *from,
29			    unsigned long n)
30{
31	while (n--)
32		*(to++) = *(from++);
33}
34
35static inline int copy_from_user(void *to, const void __user volatile *from,
36				 unsigned long n)
37{
38	__chk_user_ptr(from, n);
39	volatile_memcpy(to, from, n);
40	return 0;
41}
42
43static inline int copy_to_user(void __user volatile *to, const void *from,
44			       unsigned long n)
45{
46	__chk_user_ptr(to, n);
47	volatile_memcpy(to, from, n);
48	return 0;
49}
50#endif /* UACCESS_H */
51