From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754080AbaHKOwq (ORCPT ); Mon, 11 Aug 2014 10:52:46 -0400 Received: from terminus.zytor.com ([198.137.202.10]:52594 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753836AbaHKOwo (ORCPT ); Mon, 11 Aug 2014 10:52:44 -0400 Message-ID: <53E8D876.1060004@zytor.com> Date: Mon, 11 Aug 2014 07:51:34 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.7.0 MIME-Version: 1.0 To: Henrique de Moraes Holschuh , Borislav Petkov , Fenghua Yu CC: linux-kernel@vger.kernel.org Subject: Re: BUG: early intel microcode update violating alignment rules References: <20140809231911.GA4843@khazad-dum.debian.net> In-Reply-To: <20140809231911.GA4843@khazad-dum.debian.net> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/09/2014 04:19 PM, Henrique de Moraes Holschuh wrote: > > This will only happen when the microcode update file data inside the early > initramfs archive is not 16-byte aligned. Unfortunately, the cpio format > used in the early initramfs aligns the member file data just to 4-byte > boundaries. > > Is there a way to fix this in the kernel for the BSP? We already have > several microcode updates that are >16KiB in size and they seem to be > getting bigger and bigger, so doing it on the stack is out. > > Maybe there is a 64KiB scratch area that could be used just to get the BSP > microcode update done? vmalloc isn't available that early, but it can be > used to fix the issue for the APs. > We could put a buffer in the initdata region (we really could use an initbss region!) or in the brk. -hpa