Use armv8 instructions to optimize ARM32 crypto

[Arnd Bergmann]

On Thursday 08 January 2015 21:29:54 hong-rong hsu wrote:
> Excuse me, add more reviewers.
> 
> On Mon, 2015-01-05 at 18:12 +0800, hong-rong hsu wrote:
> > Hi,
> > 
> > We are engineers from Mediatek. We have a patch to optimize ARM32 kernel
> > crypto performance by armv8 instructions. Do you have interest in it?
> > 
> > It may be helpful for some projects which running 32-bit kernel at
> > armv8. Do you suggest that we maintain it at the main-stream :-)? (ex.
> > add aes-armv8.S in arch/arm/crypto/ folder)

It sounds like this is just an additional driver, so that should not
be a problem.

A slight concern that I have is that we don't really support ARMv8
in 32-bit mode. There are a few differences between v7 and v8, and
building the kernel with -march=armv8 will currently result in build
warnings for deprecated assembler instructions, IIRC.

	Arnd