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Re: [Xen-devel] Breakage in -unstable for Transmeta

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

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

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