From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756467Ab3KLHT7 (ORCPT ); Tue, 12 Nov 2013 02:19:59 -0500 Received: from mga03.intel.com ([143.182.124.21]:3079 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756431Ab3KLHTr (ORCPT ); Tue, 12 Nov 2013 02:19:47 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.93,683,1378882800"; d="scan'208";a="426043943" Message-ID: <5281D682.4040700@linux.intel.com> Date: Mon, 11 Nov 2013 23:19:30 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Ingo Molnar CC: Linux Kernel Mailing List , Thomas Gleixner , Olof Johansson Subject: Re: [RFC PATCH 3/3] x86, boot: Change the BIOS corruption checker to scan 640K References: <1384215407-22288-1-git-send-email-hpa@linux.intel.com> <1384215407-22288-4-git-send-email-hpa@linux.intel.com> <20131112040703.GA28410@gmail.com> In-Reply-To: <20131112040703.GA28410@gmail.com> 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 11/11/2013 08:07 PM, Ingo Molnar wrote: > I agree with your patches so far, and I'd suggest we go even further: I'd > say the config option is now a misnomer, it should probably be renamed to > CONFIG_X86_FORCE_RESERVE_BIOS_LOW_1MB=y or so. Why is that? It doesn't seem to make much sense to me. I think the current option names seem to be just fine, but perhaps I'm missing something. > Btw., should we also force-reserve the remaining bits over 640K..1MB, if > they are not marked as reserved in the memory maps, or do we already > force-reserve them somewhere? We do, in trim_bios_range(). We treat it as available for I/O assignments, since that is necessary on some systems. > The CONFIG_X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK=y option and the > memory_corruption_check=1 boot option then allow the activation of the low > memory corrupion checker - which debug facility can be used on systems > where someone wants to live dangerously and not reserve the low 1MB of RAM > to the firmware. That is indeed what this patch does, I think... -hpa