Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965446AbbLRVKB (ORCPT ); Fri, 18 Dec 2015 16:10:01 -0500 Received: from mail-io0-f177.google.com ([209.85.223.177]:34902 "EHLO mail-io0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965134AbbLRVJ6 (ORCPT ); Fri, 18 Dec 2015 16:09:58 -0500 MIME-Version: 1.0 In-Reply-To: References: <56736BD1.5080700@linux.intel.com> <5673750B.606@linux.intel.com> <567453AF.5060808@linux.intel.com> <56746774.8000707@linux.intel.com> Date: Fri, 18 Dec 2015 13:09:58 -0800 X-Google-Sender-Auth: GwX7SjGf0Aifiu8jP4eou9bVPwA Message-ID: Subject: Re: Rethinking sigcontext's xfeatures slightly for PKRU's benefit? From: Linus Torvalds To: Andy Lutomirski Cc: Dave Hansen , "H. Peter Anvin" , Oleg Nesterov , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Brian Gerst , "linux-kernel@vger.kernel.org" , Christoph Hellwig Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 824 Lines: 20 On Fri, Dec 18, 2015 at 1:04 PM, Linus Torvalds wrote: > > I do wonder if you need an explicit value, though. I think it's > reasonable to say that PKRU value 0 is special. It's what we'd start > processes with, and why not just say that it's what we run signal > handlers in? > > Would any other value ever make sense, really? Ahh. Your point about the PROT_EXEC handling means that maybe we don't want to default to zero. Maybe we want to make the default PKRU startup value be 1 instead, enabling access disable key for key 0? Linus -- 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/