From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 17363DDEED for ; Tue, 3 Jun 2008 07:54:30 +1000 (EST) Subject: Re: MMIO and gcc re-ordering issue From: Benjamin Herrenschmidt To: Ingo Molnar In-Reply-To: <20080602103643.GA21285@elte.hu> References: <1211852026.3286.36.camel@pasglop> <20080526.184047.88207142.davem@davemloft.net> <1211854540.3286.42.camel@pasglop> <20080526.192812.184590464.davem@davemloft.net> <1211859542.3286.46.camel@pasglop> <20080602103643.GA21285@elte.hu> Content-Type: text/plain Date: Tue, 03 Jun 2008 07:53:24 +1000 Message-Id: <1212443604.26672.7.camel@pasglop> Mime-Version: 1.0 Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, tpiepho@freescale.com, linuxppc-dev@ozlabs.org, scottwood@freescale.com, Linus Torvalds , David Miller , alan@lxorguk.ukuu.org.uk Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 2008-06-02 at 12:36 +0200, Ingo Molnar wrote: > The patch passed initial light testing in -tip (~30 successful random > self-builds and bootups on various mixed 32-bit/64-bit boxes) but > it's > still v2.6.27 material IMO. I think adding the "memory" clobber should be .26 and even -stable. We know for sure newer gcc will re-order things, we know it for sure some drivers will break in subtle ways because of that, ad we know as well that sticking "memory" clobber in there will fix that breakage we know about ... So I don't see the point of waiting. Ben.