linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Rik van Riel <riel@redhat.com>
To: kernel-hardening@lists.openwall.com, Jason@zx2c4.com,
	linux@sciencehorizons.net
Cc: ak@linux.intel.com, davem@davemloft.net, David.Laight@aculab.com,
	djb@cr.yp.to, ebiggers3@gmail.com, eric.dumazet@gmail.com,
	hannes@stressinduktion.org, jeanphilippe.aumasson@gmail.com,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
	luto@amacapital.net, netdev@vger.kernel.org, tom@herbertland.com,
	torvalds@linux-foundation.org, tytso@mit.edu,
	vegard.nossum@gmail.com
Subject: Re: [kernel-hardening] Re: HalfSipHash Acceptable Usage
Date: Wed, 21 Dec 2016 11:41:28 -0500	[thread overview]
Message-ID: <1482338488.11006.70.camel@redhat.com> (raw)
In-Reply-To: <20161221155540.29529.qmail@ns.sciencehorizons.net>

[-- Attachment #1: Type: text/plain, Size: 710 bytes --]

On Wed, 2016-12-21 at 10:55 -0500, George Spelvin wrote:
> Actually, DJB just made a very relevant suggestion.
> 
> As I've mentioned, the 32-bit performance problems are an x86-
> specific
> problem.  ARM does very well, and other processors aren't bad at all.
> 
> SipHash fits very nicely (and runs very fast) in the MMX registers.
> 
> They're 64 bits, and there are 8 of them, so the integer registers
> can
> be reserved for pointers and loop counters and all that.  And there's
> reference code available.
> 
> How much does kernel_fpu_begin()/kernel_fpu_end() cost?

Those can be very expensive. Almost certainly not
worth it for small amounts of data.

-- 
All Rights Reversed.

[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 473 bytes --]

  parent reply	other threads:[~2016-12-21 16:46 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-19 17:32 Jason A. Donenfeld
     [not found] ` <CAGiyFdduUNSGq24zfsk0ZU=hnOCmewAw8vw6XvDoS-3f+3UPKQ@mail.gmail.com>
2016-12-19 21:00   ` Jason A. Donenfeld
2016-12-20 21:36 ` Theodore Ts'o
2016-12-20 23:07   ` George Spelvin
2016-12-20 23:55   ` Eric Dumazet
2016-12-21  3:28     ` George Spelvin
2016-12-21  5:29       ` Eric Dumazet
2016-12-21  6:34         ` George Spelvin
2016-12-21 14:24           ` Jason A. Donenfeld
2016-12-21 15:55             ` George Spelvin
2016-12-21 16:37               ` Jason A. Donenfeld
2016-12-21 16:41               ` Rik van Riel [this message]
2016-12-21 17:25               ` Linus Torvalds
2016-12-21 18:07                 ` George Spelvin
2016-12-22  1:54                 ` Andy Lutomirski
2016-12-21 14:42         ` Jason A. Donenfeld
2016-12-21 15:56           ` Eric Dumazet
2016-12-21 16:33             ` Jason A. Donenfeld
2016-12-21 16:39             ` [kernel-hardening] " Rik van Riel
2016-12-21 17:08               ` Eric Dumazet
2016-12-21 18:37             ` George Spelvin
2016-12-21 18:40               ` Jason A. Donenfeld
2016-12-21 22:27               ` Theodore Ts'o
2016-12-22  0:18                 ` George Spelvin
2016-12-22  1:13                 ` George Spelvin
2016-12-21 22:29 [kernel-hardening] " Jason A. Donenfeld
2016-12-22  3:55 ` George Spelvin
2016-12-22  4:40   ` Jason A. Donenfeld

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1482338488.11006.70.camel@redhat.com \
    --to=riel@redhat.com \
    --cc=David.Laight@aculab.com \
    --cc=Jason@zx2c4.com \
    --cc=ak@linux.intel.com \
    --cc=davem@davemloft.net \
    --cc=djb@cr.yp.to \
    --cc=ebiggers3@gmail.com \
    --cc=eric.dumazet@gmail.com \
    --cc=hannes@stressinduktion.org \
    --cc=jeanphilippe.aumasson@gmail.com \
    --cc=kernel-hardening@lists.openwall.com \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@sciencehorizons.net \
    --cc=luto@amacapital.net \
    --cc=netdev@vger.kernel.org \
    --cc=tom@herbertland.com \
    --cc=torvalds@linux-foundation.org \
    --cc=tytso@mit.edu \
    --cc=vegard.nossum@gmail.com \
    --subject='Re: [kernel-hardening] Re: HalfSipHash Acceptable Usage' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).