From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751969AbWIRXOd (ORCPT ); Mon, 18 Sep 2006 19:14:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030252AbWIRXOd (ORCPT ); Mon, 18 Sep 2006 19:14:33 -0400 Received: from wr-out-0506.google.com ([64.233.184.226]:2720 "EHLO wr-out-0506.google.com") by vger.kernel.org with ESMTP id S1751968AbWIRXOc (ORCPT ); Mon, 18 Sep 2006 19:14:32 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=daNizltbQed8tIMz6+mXkd9kXCRMnB0gMphek2PukziGUic8sBfK78lXM2y732TV1aidFRvQh6xVnoLtE7BDhiW6XggU2pnWZt6XTr2FCSO4bGoEQk7WD0r7YpFy7qu9OUVJfs2Hnk3okVed0X0M1yHiBmHt4JdHdKNNCYKMGAI= Message-ID: <9a8748490609181614r55178f1djab68eb48bd36f7de@mail.gmail.com> Date: Tue, 19 Sep 2006 01:14:31 +0200 From: "Jesper Juhl" To: "Linus Torvalds" Subject: Re: Math-emu kills the kernel on Athlon64 X2 Cc: "Linux Kernel Mailing List" , billm@melbpc.org.au, billm@suburbia.net In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <9a8748490609181518j2d12e4f0l2c55e755e40d38c2@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 19/09/06, Linus Torvalds wrote: > > > On Tue, 19 Sep 2006, Jesper Juhl wrote: > > > > If I enable the math emulator in 2.6.18-rc7-git2 (only version I've > > tried this with) and then boot the kernel with "no387" then I only get > > as far as lilo's "...Booting the kernel." message and then the system > > hangs. > > I'm wondering if it tries to use the MMX/XMM stuff for memcpy and friends. > > I'm also wondering why you'd be doing what you seem to try to be doing in > the first place ;) > Simply to try and find bugs. If we have a math emulator and it's selectable for my CPU type, then it should damn well work ;-) > Basically, "no387" doesn't seem to disable any of the fancier FPU > features, even though it obviously should. If you ask for math emulation, > you'll get emulation faults for _all_ of the modern MMX stuff too (which > we don't do). > Hmm, I guess that could be the problem. The emulator should disable any stuff which it's not able to handle. I've not actually looked very much at the emulator code yet, so I didn't realize it didn't disable what it couldn't handle, but getting it to do that sounds like a sensible first step. > It's entirely possible that nobody has ever tested this combination. > That was my thought as well, which is exactely why I chose to try it - thinking that it might expose some bugs in math-emu or elsewhere. -- Jesper Juhl Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please http://www.expita.com/nomime.html