powerpc/thp: Handle combo pages in invalidate
authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Wed, 13 Aug 2014 07:02:00 +0000 (12:32 +0530)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>
Wed, 13 Aug 2014 08:20:39 +0000 (18:20 +1000)
commitfc0479557572375100ef16c71170b29a98e0d69a
tree89c0b9da580f2b47bcc8663deb02323052f5025b
parent629149fae478f0ac6bf705a535708b192e9c6b59
powerpc/thp: Handle combo pages in invalidate

If we changed base page size of the segment, either via sub_page_protect
or via remap_4k_pfn, we do a demote_segment which doesn't flush the hash
table entries. We do a lazy hash page table flush for all mapped pages
in the demoted segment. This happens when we handle hash page fault for
these pages.

We use _PAGE_COMBO bit along with _PAGE_HASHPTE to indicate whether a
pte is backed by 4K hash pte. If we find _PAGE_COMBO not set on the pte,
that implies that we could possibly have older 64K hash pte entries in
the hash page table and we need to invalidate those entries.

Use _PAGE_COMBO to determine the page size with which we should
invalidate the hash table entries on unmap.

CC: <stable@vger.kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
arch/powerpc/include/asm/pgtable-ppc64.h
arch/powerpc/mm/pgtable_64.c
arch/powerpc/mm/tlb_hash64.c