From owner-freebsd-current@FreeBSD.ORG Fri Feb 20 21:16:32 2015 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 8D367974 for ; Fri, 20 Feb 2015 21:16:32 +0000 (UTC) Received: from mail.wilcox-tech.com (mail.foxkit.us [192.99.209.192]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mail.wilcox-tech.com", Issuer "mail.wilcox-tech.com" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 48C2AAEF for ; Fri, 20 Feb 2015 21:16:31 +0000 (UTC) Received: (qmail 17916 invoked from network); 20 Feb 2015 21:12:48 -0000 Received: from c-71-57-141-247.hsd1.fl.comcast.net (HELO Todd) (AWilcox@Wilcox-Tech.com@71.57.141.247) by mail.foxkit.us with ESMTPA; 20 Feb 2015 21:12:48 -0000 From: "Andrew Wilcox" To: "freebsd-current" Subject: i386 port no longer bootable on non-SSE CPUs Date: Fri, 20 Feb 2015 15:09:49 -0600 Message-ID: <00c401d04d51$905fedc0$b11fc940$@Wilcox-Tech.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Mailer: Microsoft Outlook 14.0 Content-Language: en-gb Thread-Index: AdBNUYluZbK/AiOaSImZlvf2MBBTdA== X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Feb 2015 21:16:32 -0000 Hello, The i386 port, both 10-STABLE and 11-CURRENT, will not boot on systems = without SSE support. This is caused by r273995, as using `svn merge -c = -273995` (and hacking-and-sloshing through the few compiler errors = afterwards) makes it once again bootable. This crash happens very early on in boot, before even mi_startup (as the = author line is never even printed): http://i.imgur.com/SAty1mT.jpg This breaks support for all i486, Pentium, Pentium Pro, and Pentium = II-based CPUs and computers. These are not only found in older = computers that are useful as routers and file servers, but there are = some new SoCs still using these chips: Intel Galileo board http://www.frys.com/product/8080584 Pentium core, no MMX/SSE whatsoever. Released late 2014. AMD Elan SC520, Geode series http://www.eurotech.com/en/products/CPU-1421 http://www.amd.com/en-us/products/embedded/processors/lx While the Elan is no longer manufactured, it still remains popular. The = new Geode LX series of processors only implement MMX (so are roughly = equivalent to a Pentium Pro in terms of instruction set). Backing out r273995 allows boot to proceed normally, as shown here: = http://imgur.com/a/WWsa5 I attempted to revert locore.S to see if it was related to the stack = setup changes found in that commit and it made no difference; the panic = was the same. I would be willing to test any patches/diffs on any or all of the = systems I have, but unfortunately I'm in a bit over my head trying to = figure out which part of this commit is causing it. Best, Andrew -- Andrew Wilcox, C/C++/Python developer, kernel hacker Blog: http://blog.foxkit.us/ WWW: http://foxkit.us/ GitHub: https://github.com/awilfox