AArch64 Linux kernel port

This set of patches implements the core Linux support for the AArch64
(64-bit ARM) architecture.


ARM introduced AArch64 as part of the ARMv8 architecture and consists of
a substantially revised exception model (with 4 exception levels: EL0 -
user, EL1 - kernel, EL2 - hypervisor, EL3 - secure monitor), new A64
instruction set based on larger register file, new FP/SIMD instructions.
The new ABI is LP64 and takes advantage of the larger register file and
mandates FP.

AArch64 documentation currently available (publicly, though
click-through agreement required):

- Instruction Set Overview:
http://infocenter.arm.com/help/topic/com.arm.doc.genc0101...

- ABI (PCS, ELF, DWARF, C++):
http://infocenter.arm.com/help/topic/com.arm.doc.ihi0059a...

These patches are also available on this branch:

git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64.git upstream