Cross architecture analysis for Crash

Suzuki K. Poulose suzuki at in.ibm.com
Fri Jun 14 06:10:02 EDT 2013


Hi,

We have been working on enabling 'cross' analysis support for
Crash, where the target and the host differ in endian-ness.

For e.g, analysing a powerpc dump on an Intel box.

This would be useful for debugging the dumps captured on an
embedded board (say ppc44x), on a normal desktop PC(Intel based).

While the patches are being tested for 'Crash' utility we came
across a problem with the analysis of the compressed dump formats(aka 
diskdump). There is no information about the endian-ness of the dump
unlike the ELF format. Hence, we need to embed this information during
the makedumpfile processing of vmcores.

Here are some of the options we thought about :

1) Interpret the new_utsname.machine and decode the endian-ness/word
size.

2) Extend the signature string to contain information about the
endian-ness / word size.

	e.g, KDUMPB64 - for KDUMP, BigEndian 64bit

Since we don't know the endian-ness yet, we may not be able to use any
of the other fields which are 'int' or 'long' (e.g, status)

I am looking for suggestions or directions on the approach to add this
information.

Thanks
Suzuki






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