From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262374AbTD3TTY (ORCPT ); Wed, 30 Apr 2003 15:19:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262375AbTD3TTY (ORCPT ); Wed, 30 Apr 2003 15:19:24 -0400 Received: from mail.jlokier.co.uk ([81.29.64.88]:34944 "EHLO mail.jlokier.co.uk") by vger.kernel.org with ESMTP id S262374AbTD3TTW (ORCPT ); Wed, 30 Apr 2003 15:19:22 -0400 Date: Wed, 30 Apr 2003 20:31:38 +0100 From: Jamie Lokier To: "Eric W. Biederman" Cc: Gabriel Paubert , Andi Kleen , joe briggs , linux-kernel@vger.kernel.org Subject: Re: software reset Message-ID: <20030430193138.GA15981@mail.jlokier.co.uk> References: <200304291037.13598.jbriggs@briggsmedia.com.suse.lists.linux.kernel> <20030430075004.GB13859@mail.jlokier.co.uk> <20030430161525.GA3834@iram.es> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Eric W. Biederman wrote: > > On Wed, Apr 30, 2003 at 05:04:59AM -0600, Eric W. Biederman wrote: > > > > > > And as an interesting data point all a triple fault does on a modern > > > system is to put the cpu in a weird stopped state. Some hardware > > > usually the southbridge then detects this and if properly configured > > > will trigger the reset line. > > > > > > I believe this may actually go back into history as far as the 486 but > > > I have not done the researched to see how far back this behavior goes. > > > > Try 286. It was the fastest (actually only) way to make a 286 switch back > > from protected to real mode. > > A triple fault would put a 286 into coma mode? And the hardware had to > reset the chip? And then, after the reset, a flag would tell the BIOS to jump directly to application's real mode code instead of booting as usual. -- Jamie