From owner-freebsd-ppc@FreeBSD.ORG Tue Oct 14 22:58:21 2003 Return-Path: Delivered-To: freebsd-ppc@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 476D016A4B3 for ; Tue, 14 Oct 2003 22:58:21 -0700 (PDT) Received: from dommail.onthenet.com.au (dommail.OntheNet.com.au [203.13.70.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id 700DF43F3F for ; Tue, 14 Oct 2003 22:58:19 -0700 (PDT) (envelope-from grehan@freebsd.org) Received: from freebsd.org (CPE-203-45-244-178.qld.bigpond.net.au [203.45.244.178]) by dommail.onthenet.com.au (Mirapoint Messaging Server MOS 3.2.4-GA) with ESMTP id ABU05404 (AUTH peterg@ptree32.com.au); Wed, 15 Oct 2003 15:58:14 +1000 (EST) Sender: grehan@dommail.onthenet.com.au Message-ID: <3F8CE205.5CB0B9E0@freebsd.org> Date: Wed, 15 Oct 2003 15:58:29 +1000 From: Peter Grehan X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.2.14-12 i686) X-Accept-Language: en MIME-Version: 1.0 To: Alex Zepeda References: <3F8CAFAE.6260CFCF@freebsd.org> <20031015044706.GA787@blarf.homeip.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit cc: freebsd-ppc@freebsd.org Subject: Re: FYI: rudimentary loader for ppcbug-based systems X-BeenThere: freebsd-ppc@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Porting FreeBSD to the PowerPC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 15 Oct 2003 05:58:21 -0000 Hi Alex, > > Clean interfaces would be the best. The ultimate is a single kernel that could > > run on all combinations of processor and firmware, the true GENERIC, but I'm not > > sure if that's possible. > > I think this is the wrong way to go. IMO, NetBSD has the right idea. Treat each > PPC platform as a truely independent platform. They've got sys/arch/powerpc for > the truly generic stuff. Userspace is unnecessarily replicated for each of those platforms. There's a lot more differences between a lot of FreeBSD/alpha platforms than there is for the different NetBSD PPC platforms. Even properly supporting CPU differences between PPC models on the same h/w platform is perhaps more work than being able to support h/w differences in the same kernel. FreeBSD has a number of features to ease this, such as a common 3rd stage loader, devfs, etc. As I said, it may not be possible, but there's no point in writing it off from the start. > This allows them to support stuff like the BeBox, MacPPC, various IBM boxen, etc. > > This would be, IMO, similar to how FreeBSD handles the pc98 case... and the > current powerpc stuff would be split up into MI (sys/powerpc) and MD (sys/powermac > or sys/macppc maybe) portions. That's somewhat historical, and there's no need to go down that path unless necessary. > Darwin, and perhaps LinuxPPC, apparently handles the device enumeration and such > without openfirware (actually BootX more or less renders any OF stubs unuseable). > This is perhaps a nice goal, but IMO, it would be better to at least get > everything working *with* OFW. This is of course easier with the new-world > machines which have reasonable versions of OF. Darwin and LinuxPPC still use OpenFirmware - Linux pulls in a copy at boot-time before blowing it away so the info is still there. FWIW, I plan on getting things useable on NewWorld before I start out on my original goal of getting Free up and running on embedded PPC platforms. later, Peter.