1 files changed, 50 insertions, 0 deletions
diff --git a/tools/virtio/linux/uaccess.h b/tools/virtio/linux/uaccess.h
new file mode 100644
index 000000000000..0a578fe18653
--- /dev/null
+++ b/tools/virtio/linux/uaccess.h
@@ -0,0 +1,50 @@
+#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 */