From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758045AbZCMO4W (ORCPT ); Fri, 13 Mar 2009 10:56:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753568AbZCMO4M (ORCPT ); Fri, 13 Mar 2009 10:56:12 -0400 Received: from vms173017pub.verizon.net ([206.46.173.17]:60173 "EHLO vms173017pub.verizon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753118AbZCMO4M (ORCPT ); Fri, 13 Mar 2009 10:56:12 -0400 From: Gene Heskett Organization: Organization? Not detectable To: Dragoslav Zaric Subject: Re: Linux* Processor Microcode Data File Date: Fri, 13 Mar 2009 10:55:44 -0400 User-Agent: KMail/1.11.0 (Linux/2.6.28.7; KDE/4.2.0; i686; ; ) Cc: LKML References: <2d05c4580903090243k6cf73ee9ubb6c4fccf0f07a2f@mail.gmail.com> <2d05c4580903130142o2e5ebbcfw1e35eb52ea48e4b1@mail.gmail.com> <2d05c4580903130144t8e92950l7a6cb1078a8a577b@mail.gmail.com> In-reply-to: <2d05c4580903130144t8e92950l7a6cb1078a8a577b@mail.gmail.com> MIME-version: 1.0 Content-type: text/plain; charset=iso-8859-1 Content-transfer-encoding: 7bit Content-disposition: inline Message-id: <200903131055.44150.gene.heskett@verizon.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 13 March 2009, Dragoslav Zaric wrote: >--------------------------------------------- >I found this on web site http://kerneltrap.org > >Tigran Aivazian, author of the IA32 microcode driver and Microcode >Update Utility for Linux explained: > >"The answer to your question is that some Intel CPUs (just like any >other hardware or software) contain bugs >and, fortunately, their architecture is flexible enough to provide a >way to fix those bugs by means of loading the >microcode update on the fly, i.e. while the OS is running with no need >to reboot (in fact, rebooting or otherwise >resetting the CPU causes the update to be lost and requires to run the >update again)." And what runs this update? I saw it apply once in the dmesg output, about 3 full powerdown reboots ago, never since, and the code is still there in /lib/firmware AMD quad core 9550 here, stepping 03. Thanks. >--------------------------------------------- > >So when you reboot system, you reset CPU to original state, and after >that you must apply microcode, and this >is what is actually doing right now, you put microcode in folder >/etc/firmware and after boot microcode is loaded. > >So I think for CPU hotplug it is also natural that microcode is loaded >after plugging, because you can not use >microcode from boot process. Maybe kernel should have database of >tested microcodes, so when you plug CPU >appropriate microcode is loaded. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) The only thing that experience teaches us is that experience teaches us nothing. -- Andre Maurois (Emile Herzog)