Patch "powerpc/thp: Handle combo pages in invalidate" has been added to the 3.16-stable tree

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This is a note to let you know that I've just added the patch titled

    powerpc/thp: Handle combo pages in invalidate

to the 3.16-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-thp-handle-combo-pages-in-invalidate.patch
and it can be found in the queue-3.16 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From fc0479557572375100ef16c71170b29a98e0d69a Mon Sep 17 00:00:00 2001
From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Date: Wed, 13 Aug 2014 12:32:00 +0530
Subject: powerpc/thp: Handle combo pages in invalidate

From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>

commit fc0479557572375100ef16c71170b29a98e0d69a upstream.

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.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/powerpc/include/asm/pgtable-ppc64.h |    2 +-
 arch/powerpc/mm/pgtable_64.c             |   14 +++++++++++---
 arch/powerpc/mm/tlb_hash64.c             |    2 +-
 3 files changed, 13 insertions(+), 5 deletions(-)

--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -413,7 +413,7 @@ static inline char *get_hpte_slot_array(
 }
 
 extern void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr,
-				   pmd_t *pmdp);
+				   pmd_t *pmdp, unsigned long old_pmd);
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 extern pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot);
 extern pmd_t mk_pmd(struct page *page, pgprot_t pgprot);
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -538,7 +538,7 @@ unsigned long pmd_hugepage_update(struct
 	*pmdp = __pmd((old & ~clr) | set);
 #endif
 	if (old & _PAGE_HASHPTE)
-		hpte_do_hugepage_flush(mm, addr, pmdp);
+		hpte_do_hugepage_flush(mm, addr, pmdp, old);
 	return old;
 }
 
@@ -645,7 +645,7 @@ void pmdp_splitting_flush(struct vm_area
 	if (!(old & _PAGE_SPLITTING)) {
 		/* We need to flush the hpte */
 		if (old & _PAGE_HASHPTE)
-			hpte_do_hugepage_flush(vma->vm_mm, address, pmdp);
+			hpte_do_hugepage_flush(vma->vm_mm, address, pmdp, old);
 	}
 	/*
 	 * This ensures that generic code that rely on IRQ disabling
@@ -723,7 +723,7 @@ void pmdp_invalidate(struct vm_area_stru
  * neesd to be flushed.
  */
 void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr,
-			    pmd_t *pmdp)
+			    pmd_t *pmdp, unsigned long old_pmd)
 {
 	int ssize, i;
 	unsigned long s_addr;
@@ -746,7 +746,15 @@ void hpte_do_hugepage_flush(struct mm_st
 		return;
 
 	/* get the base page size,vsid and segment size */
+#ifdef CONFIG_DEBUG_VM
 	psize = get_slice_psize(mm, s_addr);
+	BUG_ON(psize == MMU_PAGE_16M);
+#endif
+	if (old_pmd & _PAGE_COMBO)
+		psize = MMU_PAGE_4K;
+	else
+		psize = MMU_PAGE_64K;
+
 	if (!is_kernel_addr(s_addr)) {
 		ssize = user_segment_size(s_addr);
 		vsid = get_vsid(mm->context.id, s_addr, ssize);
--- a/arch/powerpc/mm/tlb_hash64.c
+++ b/arch/powerpc/mm/tlb_hash64.c
@@ -216,7 +216,7 @@ void __flush_hash_table_range(struct mm_
 		if (!(pte & _PAGE_HASHPTE))
 			continue;
 		if (unlikely(hugepage_shift && pmd_trans_huge(*(pmd_t *)pte)))
-			hpte_do_hugepage_flush(mm, start, (pmd_t *)pte);
+			hpte_do_hugepage_flush(mm, start, (pmd_t *)ptep, pte);
 		else
 			hpte_need_flush(mm, start, ptep, pte, 0);
 	}


Patches currently in stable-queue which might be from aneesh.kumar@xxxxxxxxxxxxxxxxxx are

queue-3.16/powerpc-thp-use-access_once-when-loading-pmdp.patch
queue-3.16/powerpc-thp-add-write-barrier-after-updating-the-valid-bit.patch
queue-3.16/powerpc-mm-use-read-barrier-when-creating-real_pte.patch
queue-3.16/powerpc-thp-handle-combo-pages-in-invalidate.patch
queue-3.16/powerpc-thp-invalidate-old-64k-based-hash-page-mapping-before-insert-of-4k-pte.patch
queue-3.16/powerpc-thp-invalidate-with-vpn-in-loop.patch
queue-3.16/powerpc-thp-don-t-recompute-vsid-and-ssize-in-loop-on-invalidate.patch
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