r13 is non-volatile?

Kumar Gala kumar.gala at freescale.com
Fri Sep 9 11:30:58 EST 2005

On Sep 8, 2005, at 4:53 PM, Benjamin Herrenschmidt wrote:

>> There's a different value in R13 depending on which cpu you're on,
>> so one mustn't save R13 on one CPU and attempt to restore it on
>> another.
>> Maybe, for ppc32, you can pretend that r13 "is like a paca"? So
>> that instead of saving/restoring r13 like this, you could set it up
>> at the same time/instead of setting up the paca r13?
> ppc32 uses r2 for that, it contains "current".
> I don't think we need to bother merging those low level CPU specific
> things. We need to have a cpu32 and a cpu64 subdirs in there for  
> things
> like these, memory management, etc... imho.

My intent is to see if we can make a change so that there isn't an  

- kumar

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