powerpc: Fix bad pmd error with book3E config
Aneesh Kumar K.V [Wed, 19 Jun 2013 06:34:26 +0000 (11:34 +0530)]
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>

arch/powerpc/mm/hugetlbpage.c

index 237c8e5..77fdd2c 100644 (file)
@@ -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