Building an OpenBSD Kernel

I’m running OpenBSD-current for a while in order to support my port. It’s currently only one port, but that’s a start, right?

Anyway… every once in a while I stumble over a patch on the OpenBSD Mailinglist I want to try and this requires me to apply the patch and build the custom kernel with it. But how?

Well, the documentation is where you would expect it.

Download the kernel source cd /usr cvs -qd anoncvs@anoncvs.ca.openbsd.org:/cvs checkout -P src

Update the kernel source cd /usr/src cvs -q up -Pd

Configure Kernel cd /usr/src/sys/arch/amd64/conf cp GENERIC.MP MYKERNEL config MYKERNEL

Build and install kernel (amd64) cd /sys/arch/amd64/compile/MYKERNEL make clean make make install # the old kernel is /obsd now

That’s it. Reboot.

This is ONLY the kernel. If you need to build the whole system, please consult the OpenBSD documentation (hint: release(8)).