Hi,
And it was indeed using a cached page for the segment tables. The uvm changes resulted in the page allocated for the segment tables to be entered in a manner that the current method of makeing the page non-cached no longer works. I have fixed the amiga pmap to directly change the PTE bits and my amiga now is quite happy, without excessive faulting.
Followup: I was confused about the emulated instruction problem partly because a standard netbsd-4 kernel (such as one from NetBSD-daily/netbsd4) would basically be unusable, but a kernel compiled with -m68060 doesn't exhibit any of the problems you're seeing.
Are your changes in current? I'd like to test them in netbsd-4, if you have a list of changed files.
BTW - I still have the time issue where programs which sleep don't wake up (top, systat, et cetera). The keyboard doesn't repeat, either. Not sure where that is yet. Are you seeing that?
Thanks, John