if you want to work on it some, this message talks about getting inferno working on OpenBSD using the rthreads library (the pending replacement for the userland threads russ talked about):
http://www.xs4all.nl/~mechiel/inferno/openbsd43-old.html you could likely follow a similar path for p9p if you're so inclined. inferno has since gained an explicit OpenBSD port (for those directions, remove "-old" from the above URL), but i'm not sure whether that involves working around the userland thread model or explicitly relying on rthreads.
