Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753934AbaA0VyG (ORCPT ); Mon, 27 Jan 2014 16:54:06 -0500 Received: from mail-pb0-f44.google.com ([209.85.160.44]:64156 "EHLO mail-pb0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751508AbaA0VyE (ORCPT ); Mon, 27 Jan 2014 16:54:04 -0500 Message-ID: <52E6D579.8040505@amacapital.net> Date: Mon, 27 Jan 2014 13:54:01 -0800 From: Andy Lutomirski User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: "H. Peter Anvin" , Ren Qiaowei , Ingo Molnar CC: Thomas Gleixner , Ingo Molnar , x86@kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra Subject: Re: [PATCH v3 3/4] x86, mpx: add prctl commands PR_MPX_INIT, PR_MPX_RELEASE References: <1390727338-20487-1-git-send-email-qiaowei.ren@intel.com> <1390727338-20487-4-git-send-email-qiaowei.ren@intel.com> <20140126082201.GB28831@gmail.com> <52E4C5F2.8070707@intel.com> <20140126083942.GB29339@gmail.com> <52E5BB66.8060104@zytor.com> <52E5BC9C.9070400@intel.com> <52E5C000.1050506@zytor.com> In-Reply-To: <52E5C000.1050506@zytor.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/26/2014 06:10 PM, H. Peter Anvin wrote: > On 01/26/2014 05:55 PM, Ren Qiaowei wrote: >> >> Peter, you mean we should remove these two call and do what they do in >> user-space, right? >> > > Unless we think there is a benefit to the kernel to have a on/off switch > for the #BR exception (if disabled, all #BR exceptions are signals, > regardless of source.) Yes. For example, wouldn't UML want to have all of this stuff disabled? Presumably it would much prefer to receive the exception directly. The same goes for seccomp users -- as it currently stands, this code allows mmap without a system call. This probably means that the prctl should (optionally) take a parameter that fixes the address of the L1 table -- seccomp users would probably want that. (Actually, everyone might -- this is going to have weird results if the L1 table moves.) --Andy > > There might be, would like other people's opinion. > > -hpa > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/