What was in the x86 merge for .20

[Andi Kleen <ak@suse.de>]

[The merge already made it to Linus' tree. Sorry for sending this message
late]

Most of this is for both i386 and x86-64, unless when noted

These are just some high lights. As usual there are more
smaller optimizations, cleanups etc

- paravirt support for i386: the basic hooks for replacing all 
non virtualizable instructions on x86 are in. This currently
only runs on native hardware, but will allow to link in
modules  for paravirtualized Xen/Vmware/lhype.
There are some limitations like no SMP support yet. 
- Support for a Processor Data Area (PDA) on i386. This makes
the code more similar to x86-64 and will allow some other
optimizations in the future. 
- Relocatable kernel support for i386. This allows to load 
a single kernel binary on multiple addresses. This is useful
to use kdump kernels without having to maintain separate
binaries.
- Sleazy FPU feature also supported now on i386 -- this will
give a small improvement to FPU intensive programs because
they have to do  less lazy FPU exceptions.
- When a spinlock lockup occurs print backtraces of all CPUs. This 
makes debugging deadlocks easier
- x86-64 now also spins on spinlocks with interrupts enabled when
possible.
- Various dwarf2 unwinder improvements.
In particular better debugging support for figuring out what's wrong
and the unwinder should be less likely to crash now when it finds
invalid unwinding data.
- Use more efficient cache flushing when cache attributes are changed
- Allow compiling kernel for core2.  To be really useful this
will require gcc support to compile for core2 which isn't ready yet.
- Various fixes to the MTRR code
- Some preparatory infrastructure for perfmon
- Improve TSC setup heuristics on Core2 and AMD K8
- Don't try to synchronize TSCs on boot anymore. Instead just
checks if they are synchronized or not and disable TSC use
when unsynchronized. 
- More fixes to the idle notifier
- Various other bug fixes and cleanups

-Andi