Enable AVX for SandyBridge

[Steve Conklin]

Intel Advanced Vector Extensions (AVX) introduce 256-bit vector processing capability. it's the next generation of the SSE instructions, and useful for many things, especially multi-media codecs. More about AVX at http://software.intel.com/sites/avx.

There will need to be some kernel enabling code and also to optimize some libraries that can take advantage of AVX:
- Kernel xsave/xrestore (done in 2.6.28)
- Kernel patch enabling AVX (done in 2.6.30)
- gcc( done in 4.4.2) ; binutils (done in 2.20.51.0.2 )
- glibc

The support in all components has been done for Ubuntu 9.10 but Glibc. We're request to enable AVX support in Glibc:
Sandybridge has AVX with 256bit vector registers.However,64bit dynamic linker in glibc only preserves the lower 128bits of vector registers since it isn't AVX aware. At minimum, dynamic linker should preserve all 256bit AVX registers. That means we need an AVX version for 64bit glibc. If we do that,we can also add AVX version of string/memory functions.

== Upstream Status ==
glibc 2.11 has AVX support. No more patches are required.

Linux kernel patches are accepted in 2.6.34-rc1
These are the patches:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=5b3efd500854d45d305b53c54c97db5970959980
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=2225a122ae26d542bdce523d9d87a4a7ba10e07b
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=c6a0dd7ec6fb2d4927979ed4dc562fc5c122d826
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=ff7fbc72e0c3ef7e94a27a3a918fd09ec9a30204
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=6dbbe14f21368a45aedba7eab0221857b8ad8d16