Merge of projects/pseries branch

[Nathan Whitehorn]

Yesterday, I merged projects/pseries into HEAD (r255643). To quote the 
commit message:

Log:
   Merge in support for PAPR-compliant (Power Architecture Platform
   Requirements) systems from the projects/pseries branch. This in principle
   includes all IBM POWER hardware released in the last 15 years with the
   exception of POWER3-based systems when run in 64-bit mode. The main
   development target, however, has been the PAPR logical partition support
   that is the default target in KVM on POWER and QEMU -- mileage may vary
   on actual hardware at present. Much of the heavy lifting here was done
   by Andreas Tobler.

If you want to run this in QEMU (emulators/qemu-devel from ports works), do something like this:

cd /usr/src
make buildworld buildkernel TARGET=powerpc TARGET_ARCH=powerpc64
cd /usr/src/release
make release TARGET=powerpc TARGET_ARCH=powerpc64
make install DESTDIR=~/pseries
(the above will be the steps re@ takes in the next ALPHA/BETA release (probably) after ALPHA2)

qemu-system-ppc64 -m 512 -cdrom ~/pseries/release.iso -monitor stdio 
-drive id=root,if=none,file=~/pseries/release.iso -device 
usb-storage,drive=root -vga none -usb -net nic,model=e1000,vlan=0 -net 
user,vlan=0

and switch to the serial port display. You may or may not need to enter 
this at the mountroot prompt:
cd9660:/dev/da0 ro

As you can tell from the length of the QEMU command, we are still 
missing a few drivers to run out of the box:
- PAPR LPAR virtualized SCSI
- PAPR LPAR virtualized Ethernet
- QEMU framebuffer

It is also possible that the CD image you make above will work on actual 
IBM hardware. If you happen to have any compatible hardware, test 
results would be very interesting!
-Nathan