From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756401AbZGOXJf (ORCPT ); Wed, 15 Jul 2009 19:09:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755665AbZGOXJe (ORCPT ); Wed, 15 Jul 2009 19:09:34 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:37914 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753695AbZGOXJe (ORCPT ); Wed, 15 Jul 2009 19:09:34 -0400 Date: Thu, 16 Jul 2009 00:10:16 +0100 From: Alan Cox To: Dan Williams Cc: Alan Cox , Linux Kernel Mailing List , Hans de Goede Subject: Re: Why do we probe option roms at 2K boundaries? Message-ID: <20090716001016.489fa970@lxorguk.ukuu.org.uk> In-Reply-To: <1247698965.3989.1.camel@dwillia2-linux.ch.intel.com> References: <1247698965.3989.1.camel@dwillia2-linux.ch.intel.com> X-Mailer: Claws Mail 3.7.1 (GTK+ 2.14.7; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > interrogating a data structure stored in option-rom memory. My initial > implementation involved blindly scanning from c0000 to f0000 in 512 byte > increments. Neil and others pointed out that this may not be a safe It isn't safe. If you hit certain ISA devices your system will drop dead. OTOH I doubt anyone has an intel matrix raid controller and a WD80x3 on the same box ;) > Recently Hans has been working to get Fedora up and running on a recent > Intel software RAID platform and noticed that the option-rom is no > longer visible with the 2K aligned scan. I.e. he needed to make the > following changes to the mdadm probe_roms() routine: Option ROMs should be 2K aligned. Is your data structure part of a ROM or an actual ROM header ? > Is this safe? Should the kernel be updated as well? I am assuming that > you were the one that originally introduced the 2K aligned scan with > this commit from the historical git: Actually I don't think that was me, don't remember it anyway. The man to bug at the moment on ROM magic is probably H Peter Anvin however.