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

   1#ifndef UACCESS_H
   2#define UACCESS_H
   3
   4#include <linux/compiler.h>
   5
   6extern void *__user_addr_min, *__user_addr_max;
   7
   8static inline void __chk_user_ptr(const volatile void *p, size_t size)
   9{
  10        assert(p >= __user_addr_min && p + size <= __user_addr_max);
  11}
  12
  13#define put_user(x, ptr)                                        \
  14({                                                              \
  15        typeof(ptr) __pu_ptr = (ptr);                           \
  16        __chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr));            \
  17        WRITE_ONCE(*(__pu_ptr), x);                             \
  18        0;                                                      \
  19})
  20
  21#define get_user(x, ptr)                                        \
  22({                                                              \
  23        typeof(ptr) __pu_ptr = (ptr);                           \
  24        __chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr));            \
  25        x = READ_ONCE(*(__pu_ptr));                             \
  26        0;                                                      \
  27})
  28
  29static void volatile_memcpy(volatile char *to, const volatile char *from, 
  30                            unsigned long n)
  31{
  32        while (n--)
  33                *(to++) = *(from++);
  34}
  35
  36static inline int copy_from_user(void *to, const void __user volatile *from,
  37                                 unsigned long n)
  38{
  39        __chk_user_ptr(from, n);
  40        volatile_memcpy(to, from, n);
  41        return 0;
  42}
  43
  44static inline int copy_to_user(void __user volatile *to, const void *from,
  45                               unsigned long n)
  46{
  47        __chk_user_ptr(to, n);
  48        volatile_memcpy(to, from, n);
  49        return 0;
  50}
  51#endif /* UACCESS_H */
  52