From owner-cvs-all Fri Aug 30 8:11:31 2002 Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2F31837B405 for ; Fri, 30 Aug 2002 08:11:23 -0700 (PDT) Received: from mail.speakeasy.net (mail13.speakeasy.net [216.254.0.213]) by mx1.FreeBSD.org (Postfix) with ESMTP id 16BA443E6A for ; Fri, 30 Aug 2002 08:11:22 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Received: (qmail 2887 invoked from network); 30 Aug 2002 15:11:21 -0000 Received: from unknown (HELO server.baldwin.cx) ([216.27.160.63]) (envelope-sender ) by mail13.speakeasy.net (qmail-ldap-1.03) with DES-CBC3-SHA encrypted SMTP for ; 30 Aug 2002 15:11:21 -0000 Received: from laptop.baldwin.cx (gw1.twc.weather.com [216.133.140.1]) by server.baldwin.cx (8.12.5/8.12.5) with ESMTP id g7UFBJBQ049169; Fri, 30 Aug 2002 11:11:20 -0400 (EDT) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.5.2 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <200208301459.g7UExl7N064859@freefall.freebsd.org> Date: Fri, 30 Aug 2002 11:11:22 -0400 (EDT) From: John Baldwin To: John Baldwin Subject: RE: cvs commit: src/sys/boot/i386/loader Makefile Cc: cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 30-Aug-2002 John Baldwin wrote: > jhb 2002/08/30 07:59:47 PDT > > Modified files: > sys/boot/i386/loader Makefile > Log: > Revert previous untested revision. The i386 loader consists of three parts: > At the front is btxldr, in the middle is BTX itself (our mini-kernel), and > then the 'client' (loader.bin) which is the actual loader itself. boot2 > just executes a raw ELF or a.out binary with the only setup provided being > that a bootinfo structure is passed on the stack. Now, since loader.bin > is a BTX client, the loader needs to be able to locate a BTX kernel for > the client to execute in the context. Thus, just like pxelder, btxldr > uses the a.out header on the loader binary to find the BTX kernel stored > in the loader and set it up. It does _not_ just reuse the BTX kernel > that boot2 invoked it with. This is because it can't assume that it will > _have_ a "spare" BTX kernel lying around. For example, when cdboot > loads the loader there isn't an existing BTX kernel. In fact, cdboot > will only work with an a.out loader as well since it also "borrows" the > BTX kernel in the loader binary (which it finds by parsing the a.out > header) just as pxeldr does. The only difference between cdboot and > pxeldr is where they get /boot/loader from. > > If we wanted to make /boot/loader be an actual ELF binary we would need > to change the following utilites to handle that (and they all have to be > able to handle locating the BTX kernel inside of an ELF binary somehow): > - btxldr > - pxeldr > - cdboot > > If we didn't want to require a flag day but make the transition smooth > then we need to be able to support both a.out and ELF versions of > /boot/loader which isn't exactly trivial since all three of these utilities > are written in assembly. > > Pointy-hat to: peter Hmm, in hindsight this message is perhaps a bit harsh. Sorry, Peter. I don't see how you could have succesfully tested it though, the loader just won't work in any case if /boot/loader isn't a.out atm. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message