LXR linux/tools/virtio/linux/uaccess.h

   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