Fixed a compile failure when CONFIG_MODE_TT was disabled.
diff --git a/include/asm-um/uaccess.h b/include/asm-um/uaccess.h
index a638eb3..6322164 100644
--- a/include/asm-um/uaccess.h
+++ b/include/asm-um/uaccess.h
@@ -6,6 +6,8 @@
 #ifndef __UM_UACCESS_H
 #define __UM_UACCESS_H
 
+#include "linux/sched.h"
+
 #define VERIFY_READ 0
 #define VERIFY_WRITE 1