From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753725Ab3JKJ3c (ORCPT ); Fri, 11 Oct 2013 05:29:32 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:33673 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751804Ab3JKJ3b (ORCPT ); Fri, 11 Oct 2013 05:29:31 -0400 Date: Fri, 11 Oct 2013 11:28:37 +0200 From: Daniel Kiper To: ebiederm@xmission.com, hbabu@us.ibm.com, hpa@linux.intel.com, keescook@chromium.org, vgoyal@redhat.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org Cc: david.vrabel@citrix.com, jbeulich@suse.com, keir@xen.org, xen-devel@lists.xen.org Subject: kexec: Clearing registers just before jumping into purgatory Message-ID: <20131011092837.GZ3626@debian70-amd64.local.net-space.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Could you explain why do you clear all registers just before jumping into purgatory (please look into arch/x86/kernel/relocate_kernel_64.S for more details)? There is no any single word about that. I do not count comment which states what is going on. purgatory on entry does not assume any value in registers. Are you going to use that feature for something in the future (e.g. to differentiate between callers and/or Linux versions if it be needed)? By the way, interestingly it is not done if preserve_context is in force. Daniel