Re: [PATCH] ehea: Add kdump support

On Mon, 2007-11-26 at 19:16 +1100, Michael Ellerman wrote:

Hi Thomas,

I'm sorry, but this patch is all wrong IMHO.

For kdump we have to assume that the kernel is fundamentally broken,
we've panicked, so something bad has happened - every line of kernel
code that is run decreases the chance that we'll successfully make it
into the kdump kernel.

I agree with Michael.

Solutions that might be better:

 a) if there are a finite number of handles and we can predict their 
    values, just delete them all in the kdump kernel before the driver
    loads.

This is a good solution if handles are predefined.

 b) if there are a small & finite number of handles, save their values 
    in a device tree property and have the kdump kernel read them and 
    delete them before the driver loads.

Also good but is more complicated.  

 c) if neither of those work, provide a minimal routine that _only_
    deletes the handles in the crashed kernel.
 d) <something else>

Can the driver or configuration method for the driver query PHYP to
determine if there are any pre-existing mappings... 

Regards, Luke