From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755349Ab3KUWTv (ORCPT ); Thu, 21 Nov 2013 17:19:51 -0500 Received: from mail.skyhub.de ([78.46.96.112]:42961 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753318Ab3KUWTt (ORCPT ); Thu, 21 Nov 2013 17:19:49 -0500 Date: Thu, 21 Nov 2013 23:19:40 +0100 From: Borislav Petkov To: Jerry Hoemann Cc: rob@landley.net, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, matt.fleming@intel.com, yinghai@kernel.org, akpm@linux-foundation.org, bp@suse.de, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, penberg@kernel.org, mingo.kernel.org@gmail.com, vgoyal@redhat.com Subject: Re: [RFC v2 2/2] x86, efi: Early use of boot service memory Message-ID: <20131121221940.GA25681@pd.tnic> References: <1385067686-73500-1-git-send-email-jerry.hoemann@hp.com> <1385067686-73500-3-git-send-email-jerry.hoemann@hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1385067686-73500-3-git-send-email-jerry.hoemann@hp.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 21, 2013 at 02:01:26PM -0700, Jerry Hoemann wrote: > Some platform have firmware that violate the UEFI spec and access boot service > code or data segments after the system has called ExitBootServices(). > The call to efi_reserve_boot_services is a workaround to avoid using > boot service memory until after the kernel has done SetVirtualAddressMap(). > However, this reservation fragments memory which can cause > large allocations early in boot (e.g. crash kernel) to fail. > > When reserve_crashkernel fails, kdump is disabled. > > This patch creates a quirk list that governs when the workaround, > efi_reserve_boot_services, is called. > > For all firmware released prior to 2014, the workaround will be > called unless an entry for the platform is in the quirk list saying > not to do the workaround. > > For all firmware released 2014 and later, the workaround will not > be called unless an entry for the platform is in the quirk list > saying to call the workaround. This is yet another quirk list which can grow uncontrolled considering the notoriety of firmware bugs. And since detecting such spec violation is very simple - boot Linux on the machine - we should rather disable this by default for FW >= 2014 and make this test part of the firmware test suite so that vendors can get a chance to fix their BIOSen. Provided vendors do boot fwts on their validation platforms, that is. Yo Fleming, got a better idea? :) -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --