[OpenBIOS] [Qemu-ppc] FreeBSD powerpc issue

Segher Boessenkool segher at kernel.crashing.org
Sun Aug 26 21:09:21 CEST 2012

>>> Phew. I honestly have no idea how this would work at all even on
>>> Apple HW. Linux simply handles everything from real mode (disable
>>> paging) when going into anything firmware related. I have no idea
>>> what OpenBSD does. If you could try to find out and summarize it, I
>>> might be able to reconstruct how it could work :).
>> Perhaps the OpenBSD code did not flush the TLB yet?  Or does QEMU
>> emulate the TLB properly?  I seriously doubt that :-)
> Hm, s/OpenBSD/FreeBSD. :)

I have no idea :-)

> How do I flush the TLB?

tlbie, and perhaps tlbsync.

> Then I can look up in the code and see where it is done. I guess we  
> do that but the place/time might be the question.
> (Otherwise it wouldn't work on real HW, right?)

That is my theory, yes.

>> The logs do not show whether segment x'f is still mapped in the
>> SRs (or I missed it).  Is it?
> How can I enable this log or make it visible?

I have no idea.


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