Re: Breakage in -unstable for Transmeta

[Keir Fraser <Keir.Fraser@cl.cam.ac.uk>]

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