Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755513AbcCBWdY (ORCPT ); Wed, 2 Mar 2016 17:33:24 -0500 Received: from torg.zytor.com ([198.137.202.12]:49532 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754220AbcCBWdX (ORCPT ); Wed, 2 Mar 2016 17:33:23 -0500 User-Agent: K-9 Mail for Android In-Reply-To: <20160302222842.GM8362@pd.tnic> References: <20160302162530.GA8362@pd.tnic> <086BE61B-DCCC-4105-90A2-295A487C7F6F@zytor.com> <20160302181556.GD8362@pd.tnic> <56D73349.3020609@zytor.com> <20160302195053.GG8362@pd.tnic> <56D75C8D.90800@zytor.com> <20160302214654.GK8362@pd.tnic> <56D7612A.4080107@zytor.com> <20160302220954.GL8362@pd.tnic> <56D76527.5020806@zytor.com> <20160302222842.GM8362@pd.tnic> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Subject: Re: [RFC PATCH] x86: Make sure verify_cpu has a good stack From: "H. Peter Anvin" Date: Wed, 02 Mar 2016 14:32:54 -0800 To: Borislav Petkov CC: Brian Gerst , X86 ML , LKML , Tom Lendacky Message-ID: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 627 Lines: 12 On March 2, 2016 2:28:42 PM PST, Borislav Petkov wrote: >On Wed, Mar 02, 2016 at 02:11:51PM -0800, H. Peter Anvin wrote: >> Not sure if we need a reference to _text here. > >Ah, so stack_start is in .ref.data, I guess we can add a __ref_data >marker in vmlinux.lds.S to denote the start of the .ref.data section >and >use that for calculating the delta... I'm trying to think of any reason why we couldn't simply have a symbol at the top of the initial stack? Then a simple leaq would suffice; this is for the BSP after all. -- Sent from my Android device with K-9 Mail. Please excuse brevity and formatting.