From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-x232.google.com (mail-ie0-x232.google.com [IPv6:2607:f8b0:4001:c03::232]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 10C951A0040 for ; Wed, 16 Jul 2014 01:02:45 +1000 (EST) Received: by mail-ie0-f178.google.com with SMTP id tp5so4468214ieb.23 for ; Tue, 15 Jul 2014 08:02:41 -0700 (PDT) Sender: Richard Henderson Message-ID: <53C5428E.5050400@twiddle.net> Date: Tue, 15 Jul 2014 08:02:38 -0700 From: Richard Henderson MIME-Version: 1.0 To: Peter Hurley , Benjamin Herrenschmidt , Oleg Nesterov Subject: Re: bit fields && data tearing References: <20140712181328.GA8738@redhat.com> <20140712205130.GA16437@redhat.com> <1405208082.20996.54.camel@pasglop> <53C2865B.5040200@hurleysoftware.com> <1405290324.20996.71.camel@pasglop> <53C53288.0@hurleysoftware.com> In-Reply-To: <53C53288.0@hurleysoftware.com> Content-Type: text/plain; charset=UTF-8 Cc: Jakub Jelinek , linux-kernel@vger.kernel.org, Paul Mackerras , Dan , "Paul E. McKenney" , linuxppc-dev@lists.ozlabs.org, Miroslav Franc List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 07/15/2014 06:54 AM, Peter Hurley wrote: > > Jonathan Corbet wrote a LWN article about this back in 2012: > http://lwn.net/Articles/478657/ > > I guess it's fixed in gcc 4.8, but too bad there's not a workaround for > earlier compilers (akin to -fstrict_volatile_bitfields without requiring > the volatile keyword) >>From the gcc pr, it looks like the patch was backported to 4.7. But we didn't fix it in versions earlier than that. r~