From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933610AbbIDUll (ORCPT ); Fri, 4 Sep 2015 16:41:41 -0400 Received: from www.sr71.net ([198.145.64.142]:51955 "EHLO blackbird.sr71.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751033AbbIDUlk (ORCPT ); Fri, 4 Sep 2015 16:41:40 -0400 Subject: Re: [PATCH 07/12] mm: Pass the 4-bit protection key in via PROT_ bits to syscalls To: Florian Weimer References: <20150507174132.34AF8FAF@viggo.jf.intel.com> <20150507174135.FD8A0FA9@viggo.jf.intel.com> <20150507201151.5658faa1@lxorguk.ukuu.org.uk> <554BBABB.9070207@sr71.net> <87twraeydh.fsf@mid.deneb.enyo.de> <55E9FC96.7000400@sr71.net> <87pp1xgc01.fsf@mid.deneb.enyo.de> Cc: One Thousand Gnomes , linux-kernel@vger.kernel.org, x86@kernel.org From: Dave Hansen Message-ID: <55EA0203.6070202@sr71.net> Date: Fri, 4 Sep 2015 13:41:39 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <87pp1xgc01.fsf@mid.deneb.enyo.de> 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 09/04/2015 01:34 PM, Florian Weimer wrote: ...>>> It will also be very painful to add additional bits. We went through >>> this with the CPU affinity mask, and it still hurts it. Please use a >>> more sensible interface from the start. :) >> >> Any suggestions? > > It's difficult. I don't know what kind of programming model you > expect. Could glibc use these bits for its own implementation? Or > OpenSSL? Our expectation is that there will be a central "allocator" for these bits for mixed-use, like when two libraries want to control a portion of the address space for their purposes. Applications will also be completely free to implement their own, like with a language runtime.