[PATCH 0/8] Fix 8xx MMU/TLB

[Joakim Tjernlund]

Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote on 27/10/2009 01:00:53:
>
> On Mon, 2009-10-26 at 16:26 -0700, Dan Malek wrote:
> > Just be careful the get_user() doesn't regenerate the same
> > translation error you are trying to fix by being here......

yes, I had some problems with this initially but managed to work around that.
I noticed another problem though, I got multiple TLB errors for the same
address when I did it in C. Noticed by just printk:ing every hit
for a dcbX insn in do_page_fault. I can't explain it, but it seems
like when moving to C you have to execute a rfi insn and that might somehow
restart the dcbX insn before moving on to the page fault routine(or something
totally different)

>
> It shouldn't since it will always come up with a proper DAR but
> you may want to double check before hand that your instruction
> address you are loading from is -not- your marker value for bad DAR.

hmm, I check that the insn really is a dcbX insn, but not that the address is
!= 0x00f0. Don't see how it could be as if something is wrong with
the insn address you get ITLB error instead of a DTLB error.

Anyhow, things seems stalled as I haven't heard from Scott or Rex for a while.
If this isn't working now, I really don't know what is wrong and need
some debugging help.

>
> > It is nice doing things in C code, but you have to be aware
> > of the environment and the side effects when in this kind
>
> Yup.
>
> Cheers,
> Ben.
>
>
>