Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755496AbcCBSQF (ORCPT ); Wed, 2 Mar 2016 13:16:05 -0500 Received: from mail.skyhub.de ([78.46.96.112]:41745 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752210AbcCBSQD (ORCPT ); Wed, 2 Mar 2016 13:16:03 -0500 Date: Wed, 2 Mar 2016 19:15:56 +0100 From: Borislav Petkov To: "H. Peter Anvin" Cc: Brian Gerst , X86 ML , LKML , Tom Lendacky Subject: Re: [RFC PATCH] x86: Make sure verify_cpu has a good stack Message-ID: <20160302181556.GD8362@pd.tnic> References: <1456917606-4979-1-git-send-email-bp@alien8.de> <20160302162530.GA8362@pd.tnic> <086BE61B-DCCC-4105-90A2-295A487C7F6F@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <086BE61B-DCCC-4105-90A2-295A487C7F6F@zytor.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 392 Lines: 15 On Wed, Mar 02, 2016 at 09:53:28AM -0800, H. Peter Anvin wrote: > Please explain why we can't use rip-relative addressing in some form... We *can* do almost what Brian suggested: movq stack_start(%rip), %rsp subq $__START_KERNEL_map, %rsp But we still have to subtract __START_KERNEL_map. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.