Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755813AbeAHSol (ORCPT + 1 other); Mon, 8 Jan 2018 13:44:41 -0500 Received: from mga02.intel.com ([134.134.136.20]:41924 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755768AbeAHSoi (ORCPT ); Mon, 8 Jan 2018 13:44:38 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,330,1511856000"; d="scan'208";a="9106835" Subject: Re: [PATCH RFC 3/4] x86/pti: don't mark the user PGD with _PAGE_NX. To: Ingo Molnar References: <1515427939-10999-1-git-send-email-w@1wt.eu> <1515427939-10999-4-git-send-email-w@1wt.eu> <760b7264-1ae7-bcaa-6d20-f47cc7c7fce1@intel.com> <20180108175028.acwe3glhw4rsvdsx@gmail.com> Cc: Thomas Gleixner , Willy Tarreau , linux-kernel@vger.kernel.org, x86@kernel.org, gnomes@lxorguk.ukuu.org.uk, torvalds@linux-foundation.org From: Dave Hansen Message-ID: <4031a5e5-510f-49e6-ee24-f49bf5f2553d@intel.com> Date: Mon, 8 Jan 2018 10:44:37 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <20180108175028.acwe3glhw4rsvdsx@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On 01/08/2018 09:50 AM, Ingo Molnar wrote: >> This does get immensely easier if we choose a mode at exec() (or fork() >> even) and never change it. The prctl() _could_ just be a flag to tell >> what your children should do. > Switching PTI on/off for a whole process would be nightmarish. Yeah, totally. I meant "future children" aka. things *after* fork().