[PATCH] powerpc: Fix bad pmd error with book3E config

[Aneesh Kumar K.V]

From: "Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com>

Book3E uses the hugepd at PMD level and don't encode pte directly
at the pmd level. So it will find the lower bits of pmd set
and the pmd_bad check throws error. Infact the current code
will never take the free_hugepd_range call at all because it will
clear the pmd if it find a hugepd pointer.

Reported-by: Scott Wood <scottwood at freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
---
 arch/powerpc/mm/hugetlbpage.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index f2f01fd..0d3d3ee 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -536,19 +536,26 @@ static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
 	do {
 		pmd = pmd_offset(pud, addr);
 		next = pmd_addr_end(addr, end);
-		if (pmd_none_or_clear_bad(pmd))
-			continue;
+		if (!is_hugepd(pmd)) {
+			/*
+			 * if it is not hugepd pointer, we should already find
+			 * it cleared.
+			 */
+			if (!pmd_none_or_clear_bad(pmd))
+				WARN_ON(1);
+		} else {
 #ifdef CONFIG_PPC_FSL_BOOK3E
-		/*
-		 * Increment next by the size of the huge mapping since
-		 * there may be more than one entry at this level for a
-		 * single hugepage, but all of them point to
-		 * the same kmem cache that holds the hugepte.
-		 */
-		next = addr + (1 << hugepd_shift(*(hugepd_t *)pmd));
+			/*
+			 * Increment next by the size of the huge mapping since
+			 * there may be more than one entry at this level for a
+			 * single hugepage, but all of them point to
+			 * the same kmem cache that holds the hugepte.
+			 */
+			next = addr + (1 << hugepd_shift(*(hugepd_t *)pmd));
 #endif
-		free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
-				  addr, next, floor, ceiling);
+			free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
+					  addr, next, floor, ceiling);
+		}
 	} while (addr = next, addr != end);
 
 	start &= PUD_MASK;
-- 
1.8.1.2