Comment 3 for bug 2029382

Yeah, you would need a Config. Some of the BSD patch authors seem to like to have a bit of config that is common to sub-variants of BSD but it's not strictly necessary. You probably want "include Config.generic-openbsd" in Config.riscv-openbsd but I don't know if it is worth making Config.riscv-bsd unless you can guess what common elements would be needed for FreeBSD, NetBSD.
In terms of what will need to go in the C file, I have no helpful advice. It should be some synthesis of the riscv-linux.c file and maybe arm64-bsd-os.c