From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753368AbbAOUAu (ORCPT ); Thu, 15 Jan 2015 15:00:50 -0500 Received: from terminus.zytor.com ([198.137.202.10]:53844 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752135AbbAOUAt (ORCPT ); Thu, 15 Jan 2015 15:00:49 -0500 Message-ID: <54B81C2E.2090909@zytor.com> Date: Thu, 15 Jan 2015 11:59:42 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Matt Fleming , Andy Lutomirski CC: LKML , "linux-efi@vger.kernel.org" , Borislav Petkov , Thomas Gleixner , Ingo Molnar , Peter Zijlstra Subject: Re: EFI mixed mode + perf = rampant triple faults References: <5491B4A8.905@amacapital.net> <20141231183739.GA28946@console-pimps.org> <20150114165151.GA3479@codeblueprint.co.uk> <20150115194127.GB12079@codeblueprint.co.uk> In-Reply-To: <20150115194127.GB12079@codeblueprint.co.uk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/15/2015 11:41 AM, Matt Fleming wrote: >> >> Tianocore makes assumptions about the kernel's GDT layout? Yuck. > > No, but 32-bit Tianocore does rely on the second GDT entry being a > 32-bit CS. > > It has no knowledge of Linux's GDT layout. > If it assumes that descriptor 16 is a 32-bit CS (and what about data? 24?) that *is* making assumptions on the kernel. -hpa