From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754109AbYAYAUw (ORCPT ); Thu, 24 Jan 2008 19:20:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751820AbYAYAUo (ORCPT ); Thu, 24 Jan 2008 19:20:44 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:43254 "EHLO amd.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751407AbYAYAUn (ORCPT ); Thu, 24 Jan 2008 19:20:43 -0500 Date: Fri, 25 Jan 2008 01:20:54 +0100 From: Pavel Machek To: "H. Peter Anvin" , "Rafael J. Wysocki" Cc: Jeremy Fitzhardinge , Ian Campbell , Ingo Molnar , Mika =?iso-8859-1?Q?Penttil=E4?= , linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "Eric W. Biederman" Subject: Re: [PATCH] x86: Construct 32 bit boot time page tables in native format. Message-ID: <20080125002054.GA2059@elf.ucw.cz> References: <1201121530.30671.15.camel@cthulhu.hellion.org.uk> <4797E487.8010108@goop.org> <1201167544.30671.64.camel@cthulhu.hellion.org.uk> <47990BDC.4070008@zytor.com> <479912B0.2080506@goop.org> <479913BA.8000506@zytor.com> <47991809.9060903@goop.org> <47991A6C.8060007@zytor.com> <479921F5.9020902@goop.org> <4799247C.6090008@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4799247C.6090008@zytor.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 2008-01-24 15:51:24, H. Peter Anvin wrote: > Jeremy Fitzhardinge wrote: >> H. Peter Anvin wrote: >>> While we're mucking around in this area, there is another thing which we >>> should eventually get around to fixing: >>> >>> we need a set of page tables with an identity mapping as well as the >>> kernel mapping, for trampolining (during startup, but also during things >>> like ACPI suspend/resume.) Right now, we let those be the swapper page >>> tables, but that's probably not really a good idea, since it can hide >>> bugs. >> >> So you're suggesting a second system pagetable which has a P=V alias as >> well as the normal kernel mapping, used only when we actually need that >> alias? Sounds simple enough to arrange. >> > > I just looked at the ACPI suspend code, and it looks like it hacks its own > identity map at runtime. Pavel, am I reading that code right? Yes, I think so, I believe we do it on both 32 and 64 bit now. (It is early here. And I almost got the .c wakeup code to work... it already sets the mode). Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html