Matthew Green has committed a tiny change to <sys/lkm.h>
to fix LKM's on the NetBSD/sparc64 port. To take advantage of this,
you will need to rebuild your kernel and modload(1) with the fixed
<sys/lkm.h>. Trying to load a LKM on an old kernel will cause
a panic, and using an old modload(1) will return ENOTTY (Inappropriate
ioctl for device).
Update: This has been pulled into the netbsd-1-5 branch, so it will
be available in NetBSD 1.5.1.