Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262423AbTIOBHc (ORCPT ); Sun, 14 Sep 2003 21:07:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262424AbTIOBHc (ORCPT ); Sun, 14 Sep 2003 21:07:32 -0400 Received: from smtp2.us.dell.com ([143.166.85.133]:47009 "EHLO smtp2.us.dell.com") by vger.kernel.org with ESMTP id S262423AbTIOBHa (ORCPT ); Sun, 14 Sep 2003 21:07:30 -0400 Date: Sat, 13 Sep 2003 20:05:33 +1400 From: Matt Domsch To: Alan Cox Cc: Jeff Garzik , Linux Kernel Mailing List Subject: Re: 2.7 block ramblings (was Re: DMA for ide-scsi?) Message-ID: <20030913060533.GA16668@tux.linuxdev.us.dell.com> Reply-To: Matt Domsch References: <1063578413.2479.18.camel@dhcp23.swansea.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1063578413.2479.18.camel@dhcp23.swansea.linux.org.uk> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1682 Lines: 36 On Sun, Sep 14, 2003 at 05:26:54PM -0500, Alan Cox wrote: > On Sad, 2003-09-13 at 17:11, Matt Domsch wrote: > > system-unique disk signature to the boot disk (int13 device 80h) > > "BOOT" or something - we've got 4 bytes available in the msdos label > > for it > > int 13 is still available during the 16bit boot up phase of the kernel. > It does strike me as playing with fire, but an alternative approach > might work. Read the first 4K off the boot disk, stuff it somewhere > temporary and then in 32bit compare it with the disk starts.. This is essentially what we are proposing, only instead of reading 4K, read 1 sector and stash the 4-byte disk signature where we can get at it later, and export it via edd.o for comparison later. This much is easy, as the empty_zero_page has 512 bytes free for reading the sector in setup.S, and 4 bytes we can use to stash the signature until setup.c runs where we can copy it somewhere safe. Then export it via edd.o through /proc (2.4) or /sys (2.6). The thing that writes the signature to disk can be anything that can issue int13 calls. Right now we do it in a FreeDOS app, but a special loadlin/syslinux/isolinux used for OS installation may be simpler and not require a FreeDOS environment be run ever. -Matt -- Matt Domsch Sr. Software Engineer, Lead Engineer Dell Linux Solutions www.dell.com/linux Linux on Dell mailing lists @ http://lists.us.dell.com - 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/