From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from www.linux.org.uk (parcelfarce.linux.theplanet.co.uk [195.92.249.252]) by dsl2.external.hp.com (Postfix) with ESMTP id E7DA84852 for ; Fri, 3 Oct 2003 06:12:44 -0600 (MDT) Received: from willy by www.linux.org.uk with local (Exim 4.22) id 1A5Onb-0006BS-1f for parisc-linux@parisc-linux.org; Fri, 03 Oct 2003 13:12:43 +0100 Received: from master.debian.org ([146.82.138.7]:50855) by www.linux.org.uk with esmtp (Exim 4.22) id 1A5ORi-00062v-BT for willy@ftp.uk.linux.org; Fri, 03 Oct 2003 12:50:06 +0100 Received: from parcelfarce.linux.theplanet.co.uk (www.linux.org.uk) [195.92.249.252] by master.debian.org with esmtp (Exim 3.35 1 (Debian)) id 1A5ORe-0006Pl-00; Fri, 03 Oct 2003 06:50:02 -0500 Received: from willy by www.linux.org.uk with local (Exim 4.22) id 1A5ORb-00062e-FJ; Fri, 03 Oct 2003 12:49:59 +0100 Date: Fri, 3 Oct 2003 12:49:59 +0100 From: Matthew Wilcox To: Joel Soete Cc: Matthew Wilcox , Derek Engelhaupt Subject: Re: [parisc-linux] L2000/N4000 smp devices/boot compare?? Message-ID: <20031003114959.GM24824@parcelfarce.linux.theplanet.co.uk> References: <20031003001810.GH24824@parcelfarce.linux.theplanet.co.uk> <3F704CAF0000522B@ocpmta2.freegates.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <3F704CAF0000522B@ocpmta2.freegates.net> Resent-Message-Id: Sender: parisc-linux-admin@lists.parisc-linux.org Errors-To: parisc-linux-admin@lists.parisc-linux.org List-Help: List-Post: List-Subscribe: , List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: On Fri, Oct 03, 2003 at 08:15:03AM +0200, Joel Soete wrote: > Derek, Matthew, > > Thanks a lot for those clarification. > As I try, without any success :(, to find where 'rules for non-coherent aliases' > are not respected, I will waiting for a fix. Well, it's hard. Consider a page in the page cache. It has a kernel address and one-or-more user addresses. The user addresses all follow the coherency rules but the kernel address doesn't. If you look in Appendix F, we're not allowed to have multiple write-capable translations to the same address. I think the only way to solve this is by (ab)using kmap to ensure that kernel pages are only accessed via coherent mappings. -- "It's not Hollywood. War is real, war is primarily not about defeat or victory, it is about death. I've seen thousands and thousands of dead bodies. Do you think I want to have an academic debate on this subject?" -- Robert Fisk