diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index d3dd4ad984f6..63b33889d515 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2366,7 +2366,7 @@ static ssize_t uart_get_attr_port(struct device *dev,
 	struct tty_port *port = dev_get_drvdata(dev);
 
 	uart_get_info(port, &tmp);
-	return snprintf(buf, PAGE_SIZE, "0x%lX\n", (unsigned long)(tmp.port | (tmp.port_high << HIGH_BITS_OFFSET)));
+	return snprintf(buf, PAGE_SIZE, "0x%lX\n", (unsigned long)(tmp.port | (((unsigned long)tmp.port_high) << HIGH_BITS_OFFSET)));
 }
 
 static ssize_t uart_get_attr_irq(struct device *dev,