From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932419AbbAFSaM (ORCPT ); Tue, 6 Jan 2015 13:30:12 -0500 Received: from mga02.intel.com ([134.134.136.20]:12674 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755865AbbAFSaL (ORCPT ); Tue, 6 Jan 2015 13:30:11 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,709,1413270000"; d="scan'208";a="657660300" Message-ID: <54AC29B1.70004@linux.intel.com> Date: Tue, 06 Jan 2015 10:30:09 -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: Andy Lutomirski CC: Andi Kleen , "linux-kernel@vger.kernel.org" , X86 ML , Thomas Gleixner , ilya.enkovich@intel.com 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> <54AAFFA3.6000901@linux.intel.com> <20150106040428.GR2915@two.firstfloor.org> <54AC1FFB.7030504@linux.intel.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/06/2015 10:06 AM, Andy Lutomirski wrote: > On Tue, Jan 6, 2015 at 9:48 AM, Dave Hansen wrote: >> On 01/05/2015 09:59 PM, Andy Lutomirski wrote: >>> But I decided to check whether libmpx links against glibc, and I can't >>> find sources for it at all. Do they exist? Is there any code with >>> source available that invokes this prctl? >>> >>> If not, I personally have very little sympathy for the argument that a >>> binary buried in the depths of the Intel SDE would need to change if >>> we switched to using arch_prctl. And I think that it should issue the >>> syscall itself without using glibc, in which case the syscall wrapper >>> issue is moot. >> >> Andy, as I mentioned previously, there is code in a GCC branch that uses >> the existing prctl(). It's also been posted for review to one of the >> GCC mailing lists. I've been told that it will be in gcc 5.0. > > Can you point me to it? I found the code generation stuff in the gcc > branch, but I couldn't find the runtime. cc'ing Ilya who is working on the gcc parts... Ilya, is the MPX runtime that uses the prctl() calls available somewhere publicly that it can be grabbed? I couldn't find it in GCC SVN anywhere. >> The Intel SDE does not use the prctl() in any way that I know of. > > I found a couple references suggesting that libmpx lived in the SDE. > For example: > > https://software.intel.com/en-us/articles/using-intel-mpx-with-the-intel-software-development-emulator Andy, I think you're mistaken. The SDE allows you to run MPX code on a system without MPX support in hardware. It does not, itself, provide MPX code. The references you see there are to a runtime library that you obtain separately from the SDE. You run the library _under_ the SDE. I hope this clears things up.