Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262386AbTEKHUz (ORCPT ); Sun, 11 May 2003 03:20:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262406AbTEKHUz (ORCPT ); Sun, 11 May 2003 03:20:55 -0400 Received: from amsfep15-int.chello.nl ([213.46.243.28]:31022 "EHLO amsfep15-int.chello.nl") by vger.kernel.org with ESMTP id S262386AbTEKHUy (ORCPT ); Sun, 11 May 2003 03:20:54 -0400 From: Jos Hulzink To: Linus Torvalds , Jamie Lokier Subject: Re: [PATCH] Use correct x86 reboot vector Date: Sun, 11 May 2003 11:37:29 +0200 User-Agent: KMail/1.5 Cc: Andi Kleen , References: In-Reply-To: MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200305111137.29743.josh@stack.nl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1586 Lines: 41 On Sunday 11 May 2003 05:50, Linus Torvalds wrote: > On Sat, 10 May 2003, Jamie Lokier wrote: > > Jos Hulzink wrote: > > > For the sake of bad behaving BIOSes however, I'd vote for the f000:fff0 > > > vector, unless someone can hand me a paper that says it is wrong. > > > > I agree, for the simple reason that it is what the chip does on a > > hardware reset signal. > > Hmm.. Doesnt' a _real_ hardware reset actually use a magic segment that > isn't even really true real mode? I have this memory that the reset value > for a i386 has CS=0xf000, but the shadow base register actually contains > 0xffff0000. In other words, the CPU actually starts up in "unreal" mode, > and will fetch the first instruction from physical address 0xfffffff0. > > At least that was true on an original 386. It's something that could > easily have changed since. > > In other words, you're all wrong. Nyaah, nyaah. > > Linus Source: 80386 Programmers Reference Manual, Intel (1986) EIP is set 0000FFF0H CS is set F000H After RESET, lines A31-A20 are FORCED high till a far JMP is done. So, unfortunately we have to say Linus is right once again. Damn ;-) My conclusion is that we are unable to use the CPU reset as the reference for warm boots, for we can't control A312-A20 in real mode. But as far as I can see, my arguments still hold... Jos Jos - 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/