Re: [PATCH net-next v3 05/17] zinc: ChaCha20 x86_64 implementation

[Samuel Neves]

On Tue, Sep 11, 2018 at 9:22 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> On Mon, 10 Sep 2018, Jason A. Donenfeld wrote:
>>  lib/zinc/Makefile                        |    4 +
>>  lib/zinc/chacha20/chacha20-x86_64-glue.h |  102 +
>>  lib/zinc/chacha20/chacha20-x86_64.S      | 2632 ++++++++++++++++++++++
>
> Just a stupid question. What's the rationale of putting that into lib/zinc
> instead of having it in arch/x86/crypto?
>

This is covered on the 02/17 commit message, whose relevant paragraph follows:

> It also organizes the implementations in a simple, straight-forward,
> and direct manner, making it enjoyable and intuitive to work on.
> Rather than moving optimized assembly implementations into arch/, it
> keeps them all together in lib/zinc/, making it simple and obvious to
> compare and contrast what's happening. This is, notably, exactly what
> the lib/raid6/ tree does, and that seems to work out rather well. It's
> also the pattern of most successful crypto libraries. The architecture-
> specific glue-code is made a part of each translation unit, rather than
> being in a separate one, so that generic and architecture-optimized code
> are combined at compile-time, and incompatibility branches compiled out by
> the optimizer.