Benjamin Herrenschmidt [off-list ref] wrote on 04/10/2009 22:26:42:

On Sun, 2009-10-04 at 10:35 +0200, Joakim Tjernlund wrote:

quoted

Benjamin Herrenschmidt [off-list ref] wrote on 03/10/2009 12:57:28:

quoted

On Sat, 2009-10-03 at 11:24 +0200, Joakim Tjernlund wrote:

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So yes, there is a missing _tlbil_va() missing for 8xx somewhere
but there is something more too.
Maybe your new filter functions and my
 powerpc, 8xx: DTLB Error must check for more errors.
will do the trick?

Well, if we can't tell between a load and a store on a TLB miss, then
we should probably let it create an unpopulated entry in all cases,
so that we do take a proper DSI/ISI the second time around, which
would then tell us where we come from...

While looking closer on 8xx TLB handling I noticed we were taking
an extra TLB Error when making a page dirty. Tracked it down to:
static inline pte_t pte_mkdirty(pte_t pte) {
   pte_val(pte) |= _PAGE_DIRTY; return pte; }
pte_mkdirty does not set HWWRITE thus forcing a new
TLB error to clear it. Adding HWWRITE to pte_mkdirty fixes the
problem.

We should just get rid of HWWRITE like I did for 44x and BookE.

I am trying :)

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Looking at (especially pte_mkclean):
static inline pte_t pte_wrprotect(pte_t pte) {
   pte_val(pte) &= ~(_PAGE_RW | _PAGE_HWWRITE); return pte; }
static inline pte_t pte_mkclean(pte_t pte) {
   pte_val(pte) &= ~(_PAGE_DIRTY | _PAGE_HWWRITE); return pte; }

it looks like a mistake not to include HWWRITE in pte_mkdirty(),
what do you think?

Maybe yes. No big deal right now, we have more important problems
to fix no ? :-)

The missing invalidate you guys need to work out. I have no clue
where to put it. If we are really lucky, getting rid of HWWRITE
might help :)