G5 boots multi-user!

[Nathan Whitehorn]

I've fixed the crashing bugs and some issues with TLB invalidation, and 
my G5 now runs stably. I can build ports, etc., and it is reasonably 
fast. Updated patch here:

http://people.freebsd.org/~nwhitehorn/g5.diff

Known bugs:
1. World builds are broken due to changes to CACHELINESIZE, so build 
world first.
2. ATA controller does not work on my iMac because of a bug with the 
controller's interrupt property.
3. The patch touches some things it shouldn't in the MI UMA allocator 
that require a better solution. Seems mostly harmless, though.
4. The patch touches some things it shouldn't in the NFS client to fix 
the bug mentioned in my last email. This breaks NFS locking.
5. No thermal or fan control.
6. No SMP.
7. CPC 945 (PCI Express) systems are untested.
8. /dev/mem does not work, so no X.

Aside from that, any single CPU G5 machine with AGP (single CPU Powermac 
G5s and iMacs) should work without noticeable problems aside from the 
broken NFS locking. Please let me know if this isn't true.
-Nathan