powerpc: Fix bad pmd error with book3E config

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. Fix this by clearing
bad pmd only if it is not a hugepd pointer.

This is regression introduced by e2b3d202d1dba8f3546ed28224ce485bc50010be
"powerpc: Switch 16GB and 16MB explicit hugepages to a different page table format"

Reported-by: Scott Wood <scottwood@freescale.com>
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/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 237c8e5f2640b79dce83c4bce7f7f66ef09fe02f..77fdd2cef33b5a2c18ac40c442645d9dc38365ad 100644 (file)
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -592,8 +592,14 @@ 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))
+               if (!is_hugepd(pmd)) {
+                       /*
+                        * if it is not hugepd pointer, we should already find
+                        * it cleared.
+                        */
+                       WARN_ON(!pmd_none_or_clear_bad(pmd));
                        continue;
+               }
 #ifdef CONFIG_PPC_FSL_BOOK3E
                /*
                 * Increment next by the size of the huge mapping since