v4.19.13 snapshot.
diff --git a/arch/um/drivers/port.h b/arch/um/drivers/port.h
new file mode 100644
index 0000000..372a80c
--- /dev/null
+++ b/arch/um/drivers/port.h
@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2001 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#ifndef __PORT_H__
+#define __PORT_H__
+
+extern void *port_data(int port);
+extern int port_wait(void *data);
+extern void port_kern_close(void *d);
+extern int port_connection(int fd, int *socket_out, int *pid_out);
+extern int port_listen_fd(int port);
+extern void port_read(int fd, void *data);
+extern void port_kern_free(void *d);
+extern int port_rcv_fd(int fd);
+extern void port_remove_dev(void *d);
+
+#endif
+