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[karo-tx-linux.git] / tools / virtio / linux / uaccess.h
1 #ifndef UACCESS_H
2 #define UACCESS_H
3 extern void *__user_addr_min, *__user_addr_max;
4
5 #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
6
7 static 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
28 static void volatile_memcpy(volatile char *to, const volatile char *from, 
29                             unsigned long n)
30 {
31         while (n--)
32                 *(to++) = *(from++);
33 }
34
35 static 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
43 static 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 */