Re: [Qemu-ppc] [OpenBIOS] FreeBSD powerpc issue

[Andreas Tobler]

On 27.08.12 23:51, Alexander Graf wrote:
> On 27.08.2012, at 13:43, Segher Boessenkool <address@hidden> wrote:
>
> > > > > How do I flush the TLB?
> > > >
> > > > tlbie, and perhaps tlbsync.
> > >
> > > The QEMU TLB only caches existing translations, never misses.
> >
> > I'm not sure what you mean here?  No PowerPC hardware that I know of
> > stores a "this address doesn't go anywhere" tag in the TLB, either
> > (I don't think the architecture allows that even).
> >
> > I also don't see what it has to do with the problem.  The scenario
> > what we think is happening: the CPU has translations for the OF code
> > space in its TLB, because it has run it before.  The kernel removes
> > the translations but doesn't do TLBIE on those.  On real hardware,
> > the TLB entries are still used.  What does QEMU do?
>
> Ah, I see. It depends. QEMU doesn't provide any guarantees that the TLB 
> survives basically. We don't flush it often for book3s, but it can still 
> happen. Maybe try to put a printf into the tlb flush handler function?

Sorry for the delay, was sick for the past days :(

You suggest to add some printf's, am I right to do that in the cputlb.c 
tlb_flush()? If not, where did you mean to do that?

And on a side note, are/were there successful boot results from other 
OS's than linux with qemu and OpenBIOS on powerpc?

I didn't find a successful report.

Thanks,
Andreas