From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: David Laight <David.Laight@aculab.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Theodore Tso <tytso@mit.edu>,
Greg KH <gregkh@linuxfoundation.org>,
Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
Subject: Re: [PATCH v2 2/2] random: use BLAKE2s instead of SHA1 in extraction
Date: Fri, 14 Jan 2022 18:31:42 +0100 [thread overview]
Message-ID: <CAHmME9o4tyG2srPGe74n+cx9nfsU-xVe7C+mf4677ojVLVBWDg@mail.gmail.com> (raw)
In-Reply-To: <05ae373684334e6581294baa8afd3238@AcuMS.aculab.com>
On Fri, Jan 14, 2022 at 6:27 PM David Laight <David.Laight@aculab.com> wrote:
>
> From: Jason A. Donenfeld
> > Sent: 11 January 2022 12:50
> >
> > On Tue, Jan 11, 2022 at 1:28 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> > > If you're really quite concerned about m68k code size, I can probably
> > > do some things to reduce that. For example, blake2s256_hmac is only
> > > used by wireguard and it could probably be made local there. And with
> > > some trivial loop re-rolling, I can shave off another 2300 bytes. And
> > > I bet I can find a few other things too. The question is: how
> > > important is this to you?
> >
> > And with another trick (see below), another extra 1000 bytes or so
> > shaved off. Aside from moving blake2s256_hmac, I'm not really super
> > enthusiastic about making these changes, but depending on how important
> > this is to you, maybe we can make something work. There are probably
> > additional possibilities too with the code.
>
> Quite clearly whoever wrote the unrolled loops needs their head examined.
> It is extremely unlikely that a cpu has enough registers to implement it
> effeciently.
Feel free to send a patch doing this, along with benchmarks. It
doesn't seem impossible to me that re-rolling the rounds might be
better on some platforms. The question is - is it really? And if so,
which ones? And for what varieties of inputs? If you put some research
into this, please do CC me on patches.
Jason
next prev parent reply other threads:[~2022-01-14 17:32 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-23 14:11 [PATCH v2 1/2] lib/crypto: blake2s: include as built-in Jason A. Donenfeld
2021-12-23 14:11 ` [PATCH v2 2/2] random: use BLAKE2s instead of SHA1 in extraction Jason A. Donenfeld
2021-12-24 20:56 ` Eric Biggers
2022-01-05 21:42 ` Eric Biggers
2021-12-27 15:52 ` Theodore Ts'o
2022-01-11 11:38 ` Geert Uytterhoeven
2022-01-11 12:28 ` Jason A. Donenfeld
2022-01-11 12:50 ` Jason A. Donenfeld
2022-01-11 12:57 ` Geert Uytterhoeven
2022-01-11 13:00 ` Jason A. Donenfeld
2022-01-11 15:46 ` David Laight
2022-01-11 18:26 ` Jason A. Donenfeld
2022-01-14 17:27 ` David Laight
2022-01-14 17:31 ` Jason A. Donenfeld [this message]
2022-01-11 12:51 ` Geert Uytterhoeven
2022-01-11 13:02 ` Jason A. Donenfeld
2022-01-11 13:49 ` [PATCH crypto 0/2] smaller blake2s code size on m68k and other small platforms Jason A. Donenfeld
2022-01-11 13:49 ` [PATCH crypto 1/2] lib/crypto: blake2s-generic: reduce code size on small systems Jason A. Donenfeld
2022-01-12 10:57 ` Geert Uytterhoeven
2022-01-12 13:16 ` Jason A. Donenfeld
2022-01-12 18:31 ` Eric Biggers
2022-01-12 18:50 ` Jason A. Donenfeld
2022-01-12 21:27 ` David Laight
2022-01-12 22:00 ` Jason A. Donenfeld
2022-01-11 13:49 ` [PATCH crypto 2/2] lib/crypto: blake2s: move hmac construction into wireguard Jason A. Donenfeld
2022-01-11 14:43 ` Ard Biesheuvel
2022-01-12 18:35 ` Eric Biggers
2022-01-11 18:10 ` [PATCH crypto v2 0/2] reduce code size from blake2s on m68k and other small platforms Jason A. Donenfeld
2022-01-11 18:10 ` [PATCH crypto v2 1/2] lib/crypto: blake2s: move hmac construction into wireguard Jason A. Donenfeld
2022-01-11 18:10 ` [PATCH crypto v2 2/2] lib/crypto: sha1: re-roll loops to reduce code size Jason A. Donenfeld
2022-01-11 22:05 ` [PATCH crypto v3 0/2] reduce code size from blake2s on m68k and other small platforms Jason A. Donenfeld
2022-01-11 22:05 ` [PATCH crypto v3 1/2] lib/crypto: blake2s: move hmac construction into wireguard Jason A. Donenfeld
2022-01-11 22:05 ` [PATCH crypto v3 2/2] lib/crypto: sha1: re-roll loops to reduce code size Jason A. Donenfeld
2022-01-12 10:59 ` [PATCH crypto v3 0/2] reduce code size from blake2s on m68k and other small platforms Geert Uytterhoeven
2022-01-12 13:18 ` Jason A. Donenfeld
2022-01-18 6:42 ` Herbert Xu
2022-01-18 11:43 ` Jason A. Donenfeld
2022-01-18 12:44 ` David Laight
2022-01-18 12:50 ` Jason A. Donenfeld
2021-12-23 14:20 ` [PATCH v2 1/2] lib/crypto: blake2s: include as built-in Ard Biesheuvel
2021-12-24 13:35 ` Greg KH
2021-12-25 9:26 ` Masahiro Yamada
2021-12-25 10:26 ` Ard Biesheuvel
2021-12-25 15:47 ` Masahiro Yamada
2021-12-27 13:43 ` Jason A. Donenfeld
2021-12-27 13:47 ` [PATCH v3] " Jason A. Donenfeld
2021-12-27 14:20 ` [PATCH v4] " Jason A. Donenfeld
2022-01-01 15:59 ` [PATCH v5] " Jason A. Donenfeld
2022-01-02 20:42 ` [PATCH v6] " Jason A. Donenfeld
2022-01-03 3:23 ` Herbert Xu
2022-01-03 3:45 ` Jason A. Donenfeld
2022-01-03 4:06 ` Herbert Xu
2022-01-03 11:57 ` Jason A. Donenfeld
2022-01-03 12:31 ` [PATCH v7] " Jason A. Donenfeld
2022-01-04 1:21 ` Herbert Xu
2022-01-04 17:02 ` Ard Biesheuvel
2022-01-04 17:04 ` Jason A. Donenfeld
2022-01-05 0:28 ` Herbert Xu
2022-01-05 21:53 ` Eric Biggers
2022-01-05 22:01 ` Ard Biesheuvel
2022-01-05 22:09 ` Eric Biggers
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