From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1767277AbXDTVkE (ORCPT ); Fri, 20 Apr 2007 17:40:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161371AbXDTVkE (ORCPT ); Fri, 20 Apr 2007 17:40:04 -0400 Received: from moutng.kundenserver.de ([212.227.126.183]:59207 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161332AbXDTVkB (ORCPT ); Fri, 20 Apr 2007 17:40:01 -0400 From: Bodo Eggert <7eggert@gmx.de> Subject: Re: how to tell linux (on x86) to ignore 1M or memory To: Rene Herman , Dave Jones , Neil Brown , Andrew Morton , Kyle McMartin , linux-kernel@vger.kernel.org, alan@redhat.com, bcollins@ubuntu.com, pjones@redhat.com Reply-To: 7eggert@gmx.de Date: Fri, 20 Apr 2007 23:39:54 +0200 References: <8bFEz-3B4-39@gated-at.bofh.it> <8c6EE-4Jj-5@gated-at.bofh.it> User-Agent: KNode/0.7.2 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7Bit Message-Id: X-be10.7eggert.dyndns.org-MailScanner-Information: See www.mailscanner.info for information X-be10.7eggert.dyndns.org-MailScanner: Found to be clean X-be10.7eggert.dyndns.org-MailScanner-From: 7eggert@gmx.de X-Provags-ID: V01U2FsdGVkX19anbb+i+9DoDY9WiYjY2rXL7fDQ4HCECYJNMt iT0IRMlLydkU4OqVkYv8gPcf//FG0AeJRRTexS4tZ01z56EEoD d+nCry0iIs2ttE+8uN3qQ== Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Rene Herman wrote: > On 04/19/2007 04:18 PM, Bart Trojanowski wrote: >> I need to preserve some state from the bios before entering protected >> mode. For now I want to copy it into some ram accessible by real-mode, >> say the last megabyte visible in real-mode. >> >> What's the easiest way to have linux ignore the megabyte starting at 15M? > > Note that real-mode can only access the first megabyte (*) and not the first > 16. 16MB is the 16-bit protected mode (286) limit. > > (*) well, the first 1M + 64K - 16 bytes using segment FFFF assuming A20 is > enabled and x > 1 in x86... Interrupt 15h, function 87h allows copying from/to extended memory. You might like to look into Ralph Brown's interrupt list for more details. You could also cpio-gzip the data and append it to the initramfs. -- Fun things to slip into your budget Does that line item say 'Personal Massage System' Oops, it's supposed to be 'Message'. Go ahead and sign the authorization, Boss; I'll correct it later. (Iike Hell I will)