From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:31957 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S1751451AbWCGSlE (ORCPT ); Tue, 7 Mar 2006 13:41:04 -0500 From: Andi Kleen Subject: Re: [PATCH] Document Linux's memory barriers Date: Tue, 7 Mar 2006 12:13:46 +0100 References: <200603071134.52962.ak@suse.de> <31492.1141753245@warthog.cambridge.redhat.com> <7621.1141756240@warthog.cambridge.redhat.com> In-Reply-To: <7621.1141756240@warthog.cambridge.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200603071213.47885.ak@suse.de> Sender: linux-arch-owner@vger.kernel.org To: David Howells Cc: torvalds@osdl.org, akpm@osdl.org, mingo@redhat.com, linux-arch@vger.kernel.org, linuxppc64-dev@ozlabs.org, linux-kernel@vger.kernel.org List-ID: On Tuesday 07 March 2006 19:30, David Howells wrote: > > You're not supposed to do it this way anyways. The official way to access > > MMIO space is using read/write[bwlq] > > True, I suppose. I should make it clear that these accessor functions imply > memory barriers, if indeed they do, I don't think they do. > and that you should use them rather than > accessing I/O registers directly (at least, outside the arch you should). Even inside the architecture it's a good idea. -Andi