Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755715AbcCBQPl (ORCPT ); Wed, 2 Mar 2016 11:15:41 -0500 Received: from mail.skyhub.de ([78.46.96.112]:42175 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752178AbcCBQPi (ORCPT ); Wed, 2 Mar 2016 11:15:38 -0500 Date: Wed, 2 Mar 2016 17:15:32 +0100 From: Borislav Petkov To: Mika =?utf-8?B?UGVudHRpbMOk?= Cc: "H. Peter Anvin" , X86 ML , LKML , Tom Lendacky Subject: Re: [RFC PATCH] x86: Make sure verify_cpu has a good stack Message-ID: <20160302161532.GK16954@pd.tnic> References: <1456917606-4979-1-git-send-email-bp@alien8.de> <56D70CE2.1050500@nextfour.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <56D70CE2.1050500@nextfour.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: 500 Lines: 21 On Wed, Mar 02, 2016 at 05:55:14PM +0200, Mika Penttilä wrote: > > + /* Setup a stack for verify_cpu */ > > + movq stack_start - __START_KERNEL_map, %rsp > > + subq $__START_KERNEL_map, %rsp > > + > > You subtract __START_KERNEL_map twice ? Yes. That's not very obvious and it took me a while. I probably should add a comment. Want to stare at it a little bit more and try to figure it out or should I explain? :-) -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.