diff --git a/libc/kernel/uapi/linux/mount.h b/libc/kernel/uapi/linux/mount.h
index 2099b48..28f233a 100644
--- a/libc/kernel/uapi/linux/mount.h
+++ b/libc/kernel/uapi/linux/mount.h
@@ -63,7 +63,8 @@
 #define MOVE_MOUNT_T_AUTOMOUNTS 0x00000020
 #define MOVE_MOUNT_T_EMPTY_PATH 0x00000040
 #define MOVE_MOUNT_SET_GROUP 0x00000100
-#define MOVE_MOUNT__MASK 0x00000177
+#define MOVE_MOUNT_BENEATH 0x00000200
+#define MOVE_MOUNT__MASK 0x00000377
 #define FSOPEN_CLOEXEC 0x00000001
 #define FSPICK_CLOEXEC 0x00000001
 #define FSPICK_SYMLINK_NOFOLLOW 0x00000002