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  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:	Tue, 6 Oct 2015 16:29:12 -0400
From:	Pranith Kumar <bobby.prani@...il.com>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
	"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" 
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: cmpxchg_double: Add missing memory clobber

On Tue, Oct 6, 2015 at 4:16 PM, H. Peter Anvin <hpa@...or.com> wrote:
>
> NAK.  We already have the "+m" for exactly this reason; adding an
> explicit memory clobber should only be used to prevent movement of
> *other* memory operations around this one (i.e. a barrier).
>

OK. If that is so, can you please explain why we need it in the
__raw_cmpxchg() case? I think it is a good idea to make cmpxchg() and
cmpxchg_double() have similar barrier semantics.

Thanks!
-- 
Pranith
--
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/

Powered by blists - more mailing lists