[PATCH] Add ifunc memcpy and memmove for aarch64

[Wilco Dijkstra]

Siddhesh wrote:
> I think it would be cleaner to put the full generic and thunderx
> implementations in separate files instead of trying to do this macro
> dance because it keeps micro-architecture details separate.  Assembly
> code is hard to maintain as it is without adding conditional compilation
> using macros.

I agree we want to avoid using conditional compilation as much as possible.
On the other hand duplication is a bad idea too, I've seen too many cases where
bugs were only fixed in one of the N duplicates.

However I'm actually wondering whether we need an ifunc for this case.
For large copies from L2 I think adding a prefetch should be benign even on 
cores that don't need it, so if the benchmarks confirm this we should consider
updating the generic memcpy.

> I also second Adhemerval's suggestion to separate the patch to add the
> framework from the one to add the thunderx ifunc.  It makes for easier
> cherry picking and git-blaming.

Agreed.

Wilco