On Wed, Jun 21, 2017 at 12:24:34PM +0530, Aneesh Kumar K.V wrote:
> Ram Pai <linux...@us.ibm.com> writes:
>
> ....
>
> > diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c
> > b/arch/powerpc/mm/hugetlbpage-hash64.c
> > index a84bb44..239ca86 100644
> > --- a/arch/powerpc/mm/hugetlbpage-hash64.c
> > +++ b/arch/powerpc/mm/hugetlbpage-hash64.c
> > @@ -22,6 +22,7 @@ int __hash_page_huge(unsigned long ea, unsigned long
> > access, unsigned long vsid,
> > pte_t *ptep, unsigned long trap, unsigned long flags,
> > int ssize, unsigned int shift, unsigned int mmu_psize)
> > {
> > + real_pte_t rpte;
> > unsigned long vpn;
> > unsigned long old_pte, new_pte;
> > unsigned long rflags, pa, sz;
> > @@ -61,6 +62,7 @@ int __hash_page_huge(unsigned long ea, unsigned long
> > access, unsigned long vsid,
> > } while(!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
> >
> > rflags = htab_convert_pte_flags(new_pte);
> > + rpte = __real_pte(__pte(old_pte), ptep);
> >
> > sz = ((1UL) << shift);
> > if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
> > @@ -71,15 +73,10 @@ int __hash_page_huge(unsigned long ea, unsigned long
> > access, unsigned long vsid,
> > /* Check if pte already has an hpte (case 2) */
> > if (unlikely(old_pte & H_PAGE_HASHPTE)) {
> > /* There MIGHT be an HPTE for this pte */
> > - unsigned long hash, slot;
> > + unsigned long gslot;
> >
> > - hash = hpt_hash(vpn, shift, ssize);
> > - if (old_pte & H_PAGE_F_SECOND)
> > - hash = ~hash;
> > - slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
> > - slot += (old_pte & H_PAGE_F_GIX) >> H_PAGE_F_GIX_SHIFT;
> > -
> > - if (mmu_hash_ops.hpte_updatepp(slot, rflags, vpn, mmu_psize,
> > + gslot = get_hidx_gslot(vpn, shift, ssize, rpte, 0);
> > + if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, mmu_psize,
> > mmu_psize, ssize, flags) == -1)
> > old_pte &= ~_PAGE_HPTEFLAGS;
> > }
> > @@ -106,8 +103,7 @@ int __hash_page_huge(unsigned long ea, unsigned long
> > access, unsigned long vsid,
> > return -1;
> > }
> >
> > - new_pte |= (slot << H_PAGE_F_GIX_SHIFT) &
> > - (H_PAGE_F_SECOND | H_PAGE_F_GIX);
> > + new_pte |= set_hidx_slot(ptep, rpte, 0, slot);
>
> We don't really need rpte here. We are just need to track one entry
> here. May be it becomes simpler if use different helpers for 4k hpte and
> others ?
actually we need rpte here. the hidx for these 64K-hpte backed PTEs are
now stored in the second half of the pte.
I have abstracted the helpers, so that the caller need not
know the location of the hidx. It comes in really handy.
RP
