From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261829AbTIPLq7 (ORCPT ); Tue, 16 Sep 2003 07:46:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261831AbTIPLq7 (ORCPT ); Tue, 16 Sep 2003 07:46:59 -0400 Received: from mail.jlokier.co.uk ([81.29.64.88]:12948 "EHLO mail.jlokier.co.uk") by vger.kernel.org with ESMTP id S261829AbTIPLq6 (ORCPT ); Tue, 16 Sep 2003 07:46:58 -0400 Date: Tue, 16 Sep 2003 12:46:36 +0100 From: Jamie Lokier To: richard.brunner@amd.com Cc: alan@lxorguk.ukuu.org.uk, davidsen@tmr.com, zwane@linuxpower.ca, linux-kernel@vger.kernel.org Subject: Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata Message-ID: <20030916114636.GF26576@mail.jlokier.co.uk> References: <99F2150714F93F448942F9A9F112634C0638B1DE@txexmtae.amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <99F2150714F93F448942F9A9F112634C0638B1DE@txexmtae.amd.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org richard.brunner@amd.com wrote: > Andi's patch solves both the kernel space and the user space > issues in a pretty small footprint. Not really. Userspace still has a problem when run on older kernels, so it will have to check for AMD and kernel version anyway before deciding to use the prefetch instruction. That, or install SIGSEGV and SIGBUS handlers to do the fixup in userspace. > The user space problem worries me more, because the expectation > is that if CPUID says the program can use perfetch, it could > and should regardless of what the kernel decided to do here. If the workaround isn't compiled in, "prefetch" should be removed from /proc/cpuinfo on the buggy chips. -- Jamie