On Thu, Oct 01, 2009 at 08:35:59AM +1000, Benjamin Herrenschmidt wrote: > >From what I can see, the TLB miss code will check _PAGE_PRESENT, and > when not set, it will -still- insert something into the TLB (unlike > all other CPU types that go straight to data access faults from there). > > So we end up populating with those unpopulated entries that will then > cause us to take a DSI (or ISI) instead of a TLB miss the next time > around ... and so we need to remove them once we do that, no ? IE. Once > we have actually put a valid PTE in. > > At least that's my understanding and why I believe we should always have > tlbil_va() in set_pte() and ptep_set_access_flags(), which boils down > in putting it into the 2 "filter" functions in the new code. > > Well.. actually, the ptep_set_access_flags() will already do a > flush_tlb_page_nohash() when the PTE is changed. So I suppose all we > really need here would be in set_pte_filter(), to do the same if we are > writing a PTE that has _PAGE_PRESENT, at least on 8xx. > > But just unconditionally doing a tlbil_va() in both the filter functions > shouldn't harm and also fix the problem, though Rex seems to indicate > that is not the case.
Adding a tlbil_va to do_page_fault makes the problem go away for me (on top of your "merge" branch) -- none of the other changes in this thread do (assuming I didn't miss any). FWIW, when it gets stuck on a fault, DSISR is 0xc0000000, and handle_mm_fault returns zero. -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
