Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261839AbTEKSX4 (ORCPT ); Sun, 11 May 2003 14:23:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261840AbTEKSX4 (ORCPT ); Sun, 11 May 2003 14:23:56 -0400 Received: from as8-6-1.ens.s.bonet.se ([217.215.92.25]:4612 "EHLO zoo.weinigel.se") by vger.kernel.org with ESMTP id S261839AbTEKSXy (ORCPT ); Sun, 11 May 2003 14:23:54 -0400 To: ebiederm@xmission.com (Eric W. Biederman) Cc: Davide Libenzi , Jamie Lokier , Jos Hulzink , Linus Torvalds , Andi Kleen , 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: Christer Weinigel Organization: Weinigel Ingenjorsbyra AB Date: 11 May 2003 20:43:26 +0200 In-Reply-To: Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 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: 1275 Lines: 34 ebiederm@xmission.com (Eric W. Biederman) writes: > Davide Libenzi writes: > Now if someone could tell me how to do a jump to 0xffff0000:0xfff0 in real > mode I would find that very interesting. Well, it should be possible to use a trick similar to the BIG REAL or UNREAL mode. Just load CS with a segment that has a base of 0xffff0000 in protected mode and then jump back to real mode. Something like this, completely untested of course, should do it: .align 4 reset_gdt: .word reset_gdt_end - reset_gdt -1 .long reset_gdt .word 0 /* 16 bit code segment starting at 0xffff0000 */ .word 0xffff, 0x0000 .byte 0xff, 0x9b, 0x00, 0xff #endif reset_gdt_end: lgdt %cs:reset_gdt ljmp $ROM_CODE_SEG, 0xfff0 /Christer -- "Just how much can I get away with and still go to heaven?" Freelance consultant specializing in device driver programming for Linux Christer Weinigel http://www.weinigel.se - 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/