From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753503Ab3ACPvG (ORCPT ); Thu, 3 Jan 2013 10:51:06 -0500 Received: from mga10.intel.com ([192.55.52.92]:10997 "EHLO fmsmga102.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753412Ab3ACPvD (ORCPT ); Thu, 3 Jan 2013 10:51:03 -0500 Message-ID: <1357228255.8203.10.camel@mfleming-mobl1.ger.corp.intel.com> Subject: Re: BUG: unable to handle kernel paging request at 000000effd870020 From: Matt Fleming To: Robin Holt Cc: Nathan Zimmer , "H. Peter Anvin" , linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com Date: Thu, 03 Jan 2013 15:50:55 +0000 In-Reply-To: <20130102210958.GD3470@sgi.com> References: <20130102172107.GA26761@gulag1.americas.sgi.com> <50E476C2.7060300@zytor.com> <50E486E7.1080903@sgi.com> <20130102210958.GD3470@sgi.com> Organization: Intel Corporation (UK) Ltd. - Registered No. 1134945 - Pipers Way, Swindon SN3 1RJ Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4 (3.4.4-2.fc17) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2013-01-02 at 15:09 -0600, Robin Holt wrote: > On Wed, Jan 02, 2013 at 01:13:43PM -0600, Nathan Zimmer wrote: > > On 01/02/2013 12:04 PM, H. Peter Anvin wrote: > > >On 01/02/2013 09:21 AM, Nathan Zimmer wrote: > > >>I am getting an early boot problem. It only happens on the larger of the > > >>machines I haven't seen it crop up on machines with more then 512 GB of ram. > > >>It shows in the latest linus kernel too. > > >> > > >>I am (wildly) guessing that what is happening is that the new_memmap that is > > >>being passed to bios is somehow placed incorrectly. > > >>I have come up with a workaround. By placing it the DMA area the issue goes > > >>away but that doesn't seem like a real fix. > > >> > > >What does your memory map look like? > > We reported this a few times (Russ Anderson and I both). The problem is > at the point in boot where the efi_enter_virtual_mode callback is, there > is no identity mapping for most of memory. If the allocation happens > to be above the 512GB (or maybe something lower than that) point, the > BIOS is not able to address this via the physical address passed to it. Right, looks like efi_call_phys_prelog() needs rewriting to install a proper identity mapping that actually addresses *all* of available memory, instead of just the first PGDIR_SIZE bytes.