From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: Breakage in -unstable for Transmeta Date: Fri, 24 Jun 2005 14:55:45 +0100 Message-ID: <193974b525123922007225148c6938fb@cl.cam.ac.uk> References: <91682d35640728e6b4e763e88bbcb465@cl.cam.ac.uk> Mime-Version: 1.0 (Apple Message framework v622) Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "Carl Holtje ;021;vcsg6;" Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On 24 Jun 2005, at 14:30, Carl Holtje ;021;vcsg6; wrote: >> Maybe the pagetable layout has changed. That write to CR0 enables >> paging so if the tables are not in a format that Transmeta likes then >> you would probably fail at that point. But I don't think the initial >> layout differs from 2.0.6... > > I apologize for being so dense, but how do I go about investigating > this > further? No apology needed -- I really cannot see where a bug has been introduced, but assuming your debug code works on one code version (2.0.6) and not the other (latest unstable), clearly a bug does exist. The only good point of the situation is that there isn't actually that much code in x86_32.S to be going wrong. It's feasible to check through it line by line and compare with 2.0.6 as you go. How about you try reducing the number of flags you set in %cr0, or double check that the code that creates the initial pagetables really is identical between 2.0.6 and unstable? Basically, like with all 'impossible' bugs, you need to think outside the box on this one and get a bit more creative/imaginative with your debugging strategies. Without having a Transmeta box and time to debug it myself, I can't really give any more immediate help with this one I'm afraid. There must be some incredibly stupid thing going on that we will be amazed we didn't spot sooner. :-) -- Keir