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>

diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index eb9261024f5192386dec97bff1ee10e62da4b7c3..7b3d54fae46f92a80dcaddf301a2ea2687beafba 100644 (file)
--- 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(pmd_t *pmdp)
 }
 
 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);

diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 5039f3b04d6ed930388282440cec48fdefda2eb6..948a81e02ddb0194bbe5bade985adf6f9cfdf040 100644 (file)
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -538,7 +538,7 @@ unsigned long pmd_hugepage_update(struct mm_struct *mm, unsigned long addr,
        *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_struct *vma,
        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_struct *vma, unsigned long address,
  * 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_struct *mm, unsigned long addr,
                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);

diff --git a/arch/powerpc/mm/tlb_hash64.c b/arch/powerpc/mm/tlb_hash64.c
index c99f6510a0b267220253249ed836e3dee4327ba7..9adda5790463acb4dd82005459efe9abfe2c082e 100644 (file)
--- 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_struct *mm, unsigned long start,
                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);
        }