> I think the best way to go about cache/TLB flushing is to simply make
> the initiating CPU busy-wait within the cross-call function until
> all CPUs are done. This will require a rewrite of all the cross-call
> stuff we have now (but that does not amount to much anyway).

That was essentially the idea beind my cache semaphore, though using
the spinwait always resulted in a hard lockup.  The semaphore ops do
nothing if panicstr is set, so should not themselves interfere with
panic (I hope :-).

--sjg