From mboxrd@z Thu Jan 1 00:00:00 1970 Reply-To: kernel-hardening@lists.openwall.com From: Andi Kleen References: <20130410192422.GA17344@www.outflux.net> <20130411083634.GA11824@gmail.com> Date: Thu, 11 Apr 2013 04:50:14 -0700 In-Reply-To: <20130411083634.GA11824@gmail.com> (Ingo Molnar's message of "Thu, 11 Apr 2013 10:36:34 +0200") Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: [kernel-hardening] Re: [PATCH v3] x86: use a read-only IDT alias on all CPUs To: Ingo Molnar Cc: Kees Cook , Alexander Duyck , Alex Shi , Jeremy Fitzhardinge , Will Drewry , Julien Tinnes , Konrad Rzeszutek Wilk , Frederic Weisbecker , Dan Rosenberg , x86@kernel.org, linux-kernel@vger.kernel.org, Steven Rostedt , Borislav Petkov , Ingo Molnar , "H. Peter Anvin" , kernel-hardening@lists.openwall.com, Thomas Gleixner , "Paul E. McKenney" , virtualization@lists.linux-foundation.org, xen-devel@lists.xensource.com List-ID: Ingo Molnar writes: > > This looks very nice to me now. Peter, any objections? it seems pointless without randomized main kernel text location, because the IDT will be still at a known per kernel fixed writable location in the direct mapping. As long as such randomization is not there it just wastes a TLB entry. -Andi -- ak@linux.intel.com -- Speaking for myself only From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933540Ab3DKLuT (ORCPT ); Thu, 11 Apr 2013 07:50:19 -0400 Received: from mga02.intel.com ([134.134.136.20]:60390 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932712Ab3DKLuS (ORCPT ); Thu, 11 Apr 2013 07:50:18 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,454,1363158000"; d="scan'208";a="316553201" From: Andi Kleen To: Ingo Molnar Cc: Kees Cook , Alexander Duyck , Alex Shi , Jeremy Fitzhardinge , Will Drewry , Julien Tinnes , Konrad Rzeszutek Wilk , Frederic Weisbecker , Dan Rosenberg , x86@kernel.org, linux-kernel@vger.kernel.org, Steven Rostedt , Borislav Petkov , Ingo Molnar , "H. Peter Anvin" , kernel-hardening@lists.openwall.com, Thomas Gleixner , "Paul E. McKenney" , virtualization@lists.linux-foundation.org, xen-devel@lists.xensource.com Subject: Re: [PATCH v3] x86: use a read-only IDT alias on all CPUs References: <20130410192422.GA17344@www.outflux.net> <20130411083634.GA11824@gmail.com> Date: Thu, 11 Apr 2013 04:50:14 -0700 In-Reply-To: <20130411083634.GA11824@gmail.com> (Ingo Molnar's message of "Thu, 11 Apr 2013 10:36:34 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar writes: > > This looks very nice to me now. Peter, any objections? it seems pointless without randomized main kernel text location, because the IDT will be still at a known per kernel fixed writable location in the direct mapping. As long as such randomization is not there it just wastes a TLB entry. -Andi -- ak@linux.intel.com -- Speaking for myself only