uaccess.h
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#ifndef UACCESS_H
#define UACCESS_H
extern void *__user_addr_min, *__user_addr_max;
#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
static inline void __chk_user_ptr(const volatile void *p, size_t size)
{
assert(p >= __user_addr_min && p + size <= __user_addr_max);
}
#define put_user(x, ptr) \
({ \
typeof(ptr) __pu_ptr = (ptr); \
__chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr)); \
ACCESS_ONCE(*(__pu_ptr)) = x; \
0; \
})
#define get_user(x, ptr) \
({ \
typeof(ptr) __pu_ptr = (ptr); \
__chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr)); \
x = ACCESS_ONCE(*(__pu_ptr)); \
0; \
})
static void volatile_memcpy(volatile char *to, const volatile char *from,
unsigned long n)
{
while (n--)
*(to++) = *(from++);
}
static inline int copy_from_user(void *to, const void __user volatile *from,
unsigned long n)
{
__chk_user_ptr(from, n);
volatile_memcpy(to, from, n);
return 0;
}
static inline int copy_to_user(void __user volatile *to, const void *from,
unsigned long n)
{
__chk_user_ptr(to, n);
volatile_memcpy(to, from, n);
return 0;
}
#endif /* UACCESS_H */