From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751832AbeCTG2M (ORCPT ); Tue, 20 Mar 2018 02:28:12 -0400 Received: from mx2.suse.de ([195.135.220.15]:53455 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751508AbeCTG2L (ORCPT ); Tue, 20 Mar 2018 02:28:11 -0400 Subject: Re: [PATCH] x86/xen: Delay get_cpu_cap until stack canary is established To: Boris Ostrovsky , Jason Andryuk Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org References: <20180319165804.10636-1-jandryuk@gmail.com> <0726a193-6ce9-e835-9eef-01c56680d30a@oracle.com> From: Juergen Gross Message-ID: <6d73d847-9f33-7dce-2f60-33481bb4776e@suse.com> Date: Tue, 20 Mar 2018 07:28:08 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <0726a193-6ce9-e835-9eef-01c56680d30a@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/03/18 23:22, Boris Ostrovsky wrote: > On 03/19/2018 12:58 PM, Jason Andryuk wrote: >> Commit 2cc42bac1c79 ("x86-64/Xen: eliminate W+X mappings") introduced a >> call to get_cpu_cap, which is fstack-protected. This is works on x86-64 > > s/This is works/This works/ > > Reviewed-by: Boris Ostrovsky > > Do we still need 4f277295e54? I'd rather keep it in order to avoid nasty problems in case something changes. After all we are trying to do an initialization in C code which should be done in assembly before entering the C part. Doing this properly for 32-bit pv-kernels would be rather difficult, but this is no reason to drop the correct solution for the 64-bit case. Juergen