[PATCH 4/8] 8xx: Fixup DAR from buggy dcbX instructions.

Joakim Tjernlund joakim.tjernlund at transmode.se
Thu Oct 15 08:10:18 EST 2009

Scott Wood <scottwood at freescale.com> wrote on 14/10/2009 22:22:25:
> Joakim Tjernlund wrote:
> > Scott Wood <scottwood at freescale.com> wrote on 14/10/2009 21:23:02:
> >> Joakim Tjernlund wrote:
> >>> BTW, you could add a test and printk in do_page_fault on address 0x000000f0.
> >>> if that ever hits there is a problem with dcbX fixup.
> >> It doesn't get any 0xf0 faults.
> >>
> >> FWIW, I'm not seeing the segfault any more, but I still get the lockup.
> >
> > Have you reverted
> >  8xx: start using dcbX instructions in various copy routines ?
> >
> > After that you could stick a
> >  b DataAccess
> >
> >  directly in the DTLB error handler to skip and dcbX fixups.
> With that, I don't see the hard lockup, but things get stuck during

You needed both to loose the hard lockup? I would think
it should be enough to revert the "various copy routines" stuff?
I figure that these routines aren't working in 8xx for other reasons
since they haven't been used on 8xx since at least early 2.4.

> bootup with everything idle.  I see this even if I revert everything but
> the "invalidate non present TLBs" patch, and I was seeing similar things
> sometimes with the other tlbil_va hacks.

OK, something else is up.

> I think there's something else going on in the 2.6 8xx code that needs
> to be fixed before we can tell what the impact of these patches is.
> I'll look into it.

Great because I am really out of ideas. Perhaps back down to 2.6.30 and test
from there?

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