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 */