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From:   Samuel Neves <sneves@dei.uc.pt>
Date:   Tue, 11 Sep 2018 10:00:07 +0100
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Subject: Re: [PATCH net-next v3 05/17] zinc: ChaCha20 x86_64 implementation
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     "Jason A. Donenfeld" <Jason@zx2c4.com>,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        davem@davemloft.net,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Andy Lutomirski <luto@kernel.org>,
        Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>,
        Andy Polyakov <appro@openssl.org>,
        Ingo Molnar <mingo@redhat.com>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>
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On Tue, Sep 11, 2018 at 9:22 AM, Thomas Gleixner <tglx@linutronix.de> 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.