From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261432AbTIKRXj (ORCPT ); Thu, 11 Sep 2003 13:23:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261434AbTIKRSA (ORCPT ); Thu, 11 Sep 2003 13:18:00 -0400 Received: from amdext2.amd.com ([163.181.251.1]:64988 "EHLO amdext2.amd.com") by vger.kernel.org with ESMTP id S261426AbTIKROx (ORCPT ); Thu, 11 Sep 2003 13:14:53 -0400 Message-ID: <99F2150714F93F448942F9A9F112634C0638B199@txexmtae.amd.com> From: richard.brunner@amd.com To: jamie@shareable.org, ak@suse.de cc: linux-kernel@vger.kernel.org, akpm@osdl.org, torvalds@osdl.org Subject: RE: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata Date: Thu, 11 Sep 2003 12:14:21 -0500 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) X-WSS-ID: 137E72F92315006-01-01 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Potentially, any address can be a candidate. If you assume a sequential access pattern for data, addresses toward the back of the cache-line (but not the last few bytes) are less likely to hit the errata because hopefully the page that the cacheline is in is already "faulted in". But that is no guarantee. ] -Rich ... ] AMD Fellow ] richard.brunner at amd com > -----Original Message----- > From: Jamie Lokier [mailto:jamie@shareable.org] > Sent: Thursday, September 11, 2003 9:59 AM > To: Andi Kleen > Cc: Brunner, Richard; linux-kernel@vger.kernel.org; > akpm@osdl.org; torvalds@osdl.org > Subject: Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata > > > Andi Kleen wrote: > > +static int is_prefetch(struct pt_regs *regs, unsigned long addr) > > Do I understand that certain values of "addr" can't be due to the > erratum? > > In which case, could you skip most of the is_prefetch() instruction > decoder with a test like this?: > > if ((addr & 3) == 0) > return 0; > > I'm not sure from the description of the erratum what, exactly, are > the possible addresses which can appear in the fault information. > > -- Jamie >