linux-kernel - Re: [PATCH 00/18] x86: Ticket lock + cmpxchg cleanup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 24 Aug 2011 16:21:17 -0700
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Jeremy Fitzhardinge <jeremy@...p.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...e.hu>,
	"the arch/x86 maintainers" <x86@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Nick Piggin <npiggin@...nel.dk>,
	Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
Subject: Re: [PATCH 00/18] x86: Ticket lock + cmpxchg cleanup

On Wed, Aug 24, 2011 at 4:09 PM, Linus Torvalds
<torvalds@...ux-foundation.org> wrote:
>
> However, the reason I disagree with it is that I don't think that it's
> any prettier at all to have the two barriers than it is to just have
> the asm.

.. and btw, we probably do need *both* barriers. We definitely need
the one before. The one after is a bit less obvious, since it is
technically legal for code to move into the locked region. However,
it's not necessarily a *good* idea for code to move into the locked
region, so the two barriers are likely the RightThing(tm). But the two
barriers are what makes me think that the C version really isn't any
better. And the OOSTORE case then just clinches the deal for me.

                         Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/