Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261275AbTEKTD0 (ORCPT ); Sun, 11 May 2003 15:03:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261288AbTEKTD0 (ORCPT ); Sun, 11 May 2003 15:03:26 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:33359 "EHLO frodo.biederman.org") by vger.kernel.org with ESMTP id S261275AbTEKTDZ (ORCPT ); Sun, 11 May 2003 15:03:25 -0400 To: Davide Libenzi Cc: Linux Kernel Mailing List Subject: Re: [PATCH] Use correct x86 reboot vector References: <200305111137.29743.josh@stack.nl> <20030511140144.GA5602@mail.jlokier.co.uk> From: ebiederm@xmission.com (Eric W. Biederman) Date: 11 May 2003 13:12:51 -0600 In-Reply-To: Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.1 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1199 Lines: 24 Davide Libenzi writes: > On Sun, 11 May 2003, Eric W. Biederman wrote: > > > The remapping is quite common but it usually happens that after bootup: > > 0xf0000-0xfffff is shadowed RAM. While 0xffff0000-0xffffffff still points > > to the rom chip. > > > > Now if someone could tell me how to do a jump to 0xffff0000:0xfff0 in real > > mode I would find that very interesting. > > Have you ever heard about unreal mode ? But I do not think that a reset > has to start over there. I do not think that exist hw/sw that expect that > reset address to be 0xfffffff0 instead of 0x000ffff0, since they map the > same content. There is some software at least that knows the difference. I have seen short jumps in a couple of BIOS's. But a reset is very different from a reboot. As memory must be reinitialized etc. So I think going to 0xffff0000:0xfff0 would be a very bad idea if the intent is to get a reliable reboot. Eric - 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/