From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932231AbYASPni (ORCPT ); Sat, 19 Jan 2008 10:43:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759164AbYASPn3 (ORCPT ); Sat, 19 Jan 2008 10:43:29 -0500 Received: from one.firstfloor.org ([213.235.205.2]:54229 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757655AbYASPn2 (ORCPT ); Sat, 19 Jan 2008 10:43:28 -0500 Date: Sat, 19 Jan 2008 16:46:51 +0100 From: Andi Kleen To: Ingo Molnar Cc: Andi Kleen , venkatesh.pallipadi@intel.com, suresh.b.siddha@intel.com, tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: ACPI early ioremap problems Message-ID: <20080119154651.GA1626@one.firstfloor.org> References: <20080119030843.GA2028@basil.nowhere.org> <20080119150328.GA32370@elte.hu> <20080119152649.GA1375@one.firstfloor.org> <20080119153055.GA12054@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080119153055.GA12054@elte.hu> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 19, 2008 at 04:30:55PM +0100, Ingo Molnar wrote: > > > that case it's a 64-bit early_ioremap() bug that we want to find > > > even if ACPI didnt use early_ioremap(). > > > > > > and this all runs before zap_low_mappings(), right? > > > > No after. Since some time x86-64 does the equivalent of z_l_m() in > > head64(); this means before start_kernel and definitely before > > setup_arch which sets up ACPI. > > that would mean early_ioremap() should switch to ioremap() after that > point. Could you try that, does it resolve the failure you are seeing? ioremap() does alloc_page and that won't work before paging_init(). Early ACPI scan is before paging_init() because paging_init() needs node discovery at at least; which requires some ACPI tables. > Long-term we want to have a single, uniform ioremap() interface (on > 32-bit and 64-bit x86 as well) that can be used anytime, which just > switches to the right lowlevel method depending on how far we are into > the pagetable and memory subsystem bootstrap - instead of these more > fragile "can we now use early_ioremap() or should we already be using > ioremap()" usages. I didn't think there were enough early/bt_ioremap() users for this to be really worthwhile. The only code that does both I'm aware of is the memory setup code. -Andi