[PATCH] add Altivec/VMX state to coredumps

Kumar Gala galak at kernel.crashing.org
Wed Sep 26 23:32:01 EST 2007

On Sep 26, 2007, at 8:21 AM, Segher Boessenkool wrote:

>>>> Why not put the PVR in core dumps that'd make it all easier..
>>> PVR wouldn't be very useful...  What if you have altivec disabled ?
>>> Also
>>> that would mean your gdb has to know about all new processors...
>> Is that such a big deal? :D
>> Hypothetically it would be impossible to determine if you were  
>> running
>> on a G5 with the FPU and AltiVec turned off or an e500 core with SPE,
>> given the data saved.
> And that is exactly as should be: a core dump represents the execution
> state of a user program, it has nothing to do with the machine it was
> generated on; it even is possible to restart a core dump generated on
> e.g. an e500 on a 970, as long as it doesn't use facilities (e.g.,  
> SPE)
> that the latter processor / execution environment doesn't provide.
>> Is that a misfeature of GDB that we even have to
>> worry about this, or some noble plus point of a unified ISA? You
>> decide :)
> We don't have to worry about it :-)

We should worry about it.  If one misinterprets the core file you  
will get unexpected behavior.  I see no reason not to do this  
properly and mark the sections such that its clear if its AltiVec or  
SPE state, rather than overloading the x86 XFPU type.

- k

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