Here's a patch to dig the PCI bus to node mapping information out of the 
deep, dank recesses of the EBDA tables for the Summit machines.  This 
info is then used for the pcibus_to_cpumask() topology function.

brief summary:
This patch adds a new file, arch/i386/kernel/summit.c, for 
summit-specific code.  Adds some structures to mach_mpparse.h.  Also 
adds a hook in setup_arch() to dig out the PCI info, and stores it in 
the mp_bus_id_to_node[] array, where it can be read by the topology 
functions.

As always, questions, comments, or praise (yeah, right) welcome!

  arch/i386/kernel/Makefile                   |    1
  arch/i386/kernel/setup.c                    |    3
  arch/i386/kernel/summit.c                   |  162 
++++++++++++++++++++++++++++
  include/asm-i386/mach-summit/mach_mpparse.h |   69 +++++++++++
  include/asm-i386/mpspec.h                   |    4
  5 files changed, 239 insertions(+)

Cheers!

-Matt