From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765464AbZARI07 (ORCPT ); Sun, 18 Jan 2009 03:26:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761339AbZARI0v (ORCPT ); Sun, 18 Jan 2009 03:26:51 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:47674 "EHLO gprs189-60.eurotel.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758044AbZARI0u (ORCPT ); Sun, 18 Jan 2009 03:26:50 -0500 Date: Sun, 18 Jan 2009 09:08:44 +0100 From: Pavel Machek To: "H. Peter Anvin" Cc: Suresh Siddha , "mingo@elte.hu" , "tglx@linutronix.de" , "Pallipadi, Venkatesh" , "linux-kernel@vger.kernel.org" , "tvignaud@mandriva.com" Subject: Re: [patch] x86, pat: fix reserve_memtype() for legacy 1MB range Message-ID: <20090118080844.GA1911@ucw.cz> References: <20090109223520.GC6472@linux-os.sc.intel.com> <4967D223.1090703@zytor.com> <20090109224804.GD6472@linux-os.sc.intel.com> <20090117174224.GA1409@ucw.cz> <497268B7.40301@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <497268B7.40301@zytor.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat 2009-01-17 15:24:39, H. Peter Anvin wrote: > Pavel Machek wrote: > > On Fri 2009-01-09 14:48:04, Suresh Siddha wrote: > >> On Fri, Jan 09, 2009 at 02:39:31PM -0800, H. Peter Anvin wrote: > >>> Suresh Siddha wrote: > >>>> Here X is trying to map first 8KB of memory using /dev/mem. Existing > >>>> code treats first 0-4KB of memory as non-RAM and 4KB-8KB as RAM. Recent > >>>> code changes don't allow to map memory with different attributes > >>>> at the same time. > >>>> > >>> Why was 0-4 KB marked as non-RAM? It is most definitely RAM, and should > >>> be WB. > >> While in reality it is RAM, we have CONFIG_STRICT_DEVMEM which doesn't allow > >> apps to map RAM pages using /dev/mem. And to allow app's to map the > >> legacy 0-4KB bios data page, we consider it as non-RAM. > > > > Fix config_strict_devmem? Ram is ram, and we should not li for > > strict_devmem benefit... > > *As far as I understand* this is only considered non-RAM for the purpose > of strict_devmem? I did not look *too* closely, but the patch at the beggining of this thread was for pat.c or something like that. I'd expect it to change /dev/mem code... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html