Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753464Ab1E2Mr3 (ORCPT ); Sun, 29 May 2011 08:47:29 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:56979 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752385Ab1E2Mr1 (ORCPT ); Sun, 29 May 2011 08:47:27 -0400 Date: Sun, 29 May 2011 14:47:02 +0200 From: Ingo Molnar To: "H. Peter Anvin" Cc: Linus Torvalds , Dan Rosenberg , "Rafael J. Wysocki" , Tony Luck , linux-kernel@vger.kernel.org, davej@redhat.com, kees.cook@canonical.com, davem@davemloft.net, eranian@google.com, adobriyan@gmail.com, penberg@kernel.org, Arjan van de Ven , Andrew Morton , Valdis.Kletnieks@vt.edu, pageexec@freemail.hu Subject: Re: [RFC][PATCH] Randomize kernel base address on boot Message-ID: <20110529124702.GE26627@elte.hu> References: <20110527170045.GB4356@elte.hu> <1306516230.3339.17.camel@dan> <20110527171611.GE4356@elte.hu> <20110527174644.GG4356@elte.hu> <4DDFE52D.4070308@zytor.com> <20110528121820.GB12059@elte.hu> <4DE19DC3.7090106@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4DE19DC3.7090106@zytor.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.3.1 -2.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 996 Lines: 28 * H. Peter Anvin wrote: > On 05/28/2011 05:18 AM, Ingo Molnar wrote: > > > > Having half a megabyte of '__init buffer' at the beginning or end > > of the kernel image is no big deal, it's more than enough for > > good randomization and makes the whole thing image-loader > > invariant: we can freely shift the 'real' kernel image within > > this larger boundary without consulting RAM maps. > > Sure, but you're also blowing any attempt at PMD alignment to > kingdom come. Do you mean we'd not start at a 2MB boundary and thus would waste on average an about 0.125 worth of huge-TLB cache entry? That does not look like a very big issue to me - but maybe i'm missing something and you mean something else. Thanks, Ingo -- 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/