http://lkiw4tmbudbr43hbyhm636sarn73vuow77czzohdbqdpjuq3vdzvenyd.onion/article/op/2016-03-05/new-stable-release-hardenedbsd-stable-11-current-v42
Now that we have OF_decode_addr(), with proper MD implementations, to obtain the bus space tag and handle for a uart console, use the values returned by that routine to set the global uart_bus_space_mem, instead of assuming that there will be a global variable named fdtbus_bs_tag to set it from. This code no longer references fdtbus_bs_tag, no need for a special extern declaration of it for aarch64.