From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753684AbcAGUtl (ORCPT ); Thu, 7 Jan 2016 15:49:41 -0500 Received: from lists.s-osg.org ([54.187.51.154]:47156 "EHLO lists.s-osg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753646AbcAGUtj (ORCPT ); Thu, 7 Jan 2016 15:49:39 -0500 Subject: Re: [PATCH] selftests/x86: Disable ldt_gdt_64 for now To: Andy Lutomirski , x86@kernel.org References: <8dd42ba6434d84eefe6d864fb453fbe34d43098c.1452109816.git.luto@kernel.org> Cc: Borislav Petkov , linux-kernel@vger.kernel.org, Shuah Khan From: Shuah Khan Organization: Samsung Open Source Group Message-ID: <568ECF61.4040007@osg.samsung.com> Date: Thu, 7 Jan 2016 13:49:37 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <8dd42ba6434d84eefe6d864fb453fbe34d43098c.1452109816.git.luto@kernel.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/06/2016 12:51 PM, Andy Lutomirski wrote: > ldt_gdt.c relies on cross-cpu invalidation of SS to do one of its > tests. On 32-bit builds, this works fine, but on 64-bit builds, it > only works if the kernel has proper SS sigcontext handling for > 64-bit user programs. > > Since the SS fixes are currently reverted, restrict the test case to > 32 bits for now. > > In principle, I could change the test to use a different segment > register, but it would be messy: CS can't point to the LDT for > 64-bit code, and the other registers don't result in immediate > faults because they aren't reloaded on kernel -> user transitions. > > When we fix sigcontext (in 4.6?), we can revert this. > > Signed-off-by: Andy Lutomirski > -- Andy, This patch didn't apply to linux-kselftest next. It probably has to go through x86. thanks, -- Shuah -- Shuah Khan Sr. Linux Kernel Developer Open Source Innovation Group Samsung Research America (Silicon Valley) shuahkh@osg.samsung.com | (970) 217-8978