From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754032AbbAEVS3 (ORCPT ); Mon, 5 Jan 2015 16:18:29 -0500 Received: from mga03.intel.com ([134.134.136.65]:45227 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753267AbbAEVS2 (ORCPT ); Mon, 5 Jan 2015 16:18:28 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,702,1413270000"; d="scan'208";a="632845216" Message-ID: <54AAFFA3.6000901@linux.intel.com> Date: Mon, 05 Jan 2015 13:18:27 -0800 From: Dave Hansen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Andi Kleen CC: Andy Lutomirski , linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner Subject: Re: [PATCH 3.19 3/3] x86, mpx: Change the MPX enable/disable API to arch_prctl References: <54A64E6D.1020304@linux.intel.com> <87mw5x0xjz.fsf@tassilo.jf.intel.com> In-Reply-To: <87mw5x0xjz.fsf@tassilo.jf.intel.com> 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 01/05/2015 12:42 PM, Andi Kleen wrote: > Dave Hansen writes: >> On 12/29/2014 04:52 PM, Andy Lutomirski wrote: >>> This has the benefit the it avoids cluttering prctl with more >>> arch-specific functionality. The down side is that arch_prctl will >>> need to be wired up as a 32-bit syscall to add 32-bit support for >>> MPX. >> >> There is existing userspace out there which depends on the existing >> prctl() setup. There isn't a _lot_ and it might still be able to be >> changed easily, but this isn't a given. >> >> I'll check in with the folks doing the gcc (runtime) part of this next >> week and see what they think. > > It'll be quite messy for 32bit because they would need to use syscall(), > as glibc won't have a arch_prctl stub. Yeah, I'd _really_ prefer not to change it. The code is in a gcc branch, but is getting pulled in to the 5.0 release. We've got *absolutely* no shortage of prctl numbers.