diff options
authorDavid Gibson <david@gibson.dropbear.id.au>2010-02-08 20:09:03 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2010-02-10 13:58:06 +1100
commit77058e1adcc439151db41f2b84e4867a88113cd8 (patch)
parentac73fddfc523bf3c3525d16356b44527c44fae6d (diff)
powerpc: Fix address masking bug in hpte_need_flush()
Commit f71dc176aa06359681c30ba6877ffccab6fba3a6 'Make hpte_need_flush() correctly mask for multiple page sizes' introduced bug, which is triggered when a kernel with a 64k base page size is run on a system whose hardware does not 64k hash PTEs. In this case, we emulate 64k pages with multiple 4k hash PTEs, however in hpte_need_flush() we incorrectly only mask the hardware page size from the address, instead of the logical page size. This causes things to go wrong when we later attempt to iterate through the hardware subpages of the logical page. This patch corrects the error. It has been tested on pSeries bare metal by Michael Neuling. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/powerpc/mm/tlb_hash64.c b/arch/powerpc/mm/tlb_hash64.c
index 282d9306361f..1ec06576f619 100644
--- a/arch/powerpc/mm/tlb_hash64.c
+++ b/arch/powerpc/mm/tlb_hash64.c
@@ -63,15 +63,21 @@ void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
if (huge) {
psize = get_slice_psize(mm, addr);
+ /* Mask the address for the correct page size */
+ addr &= ~((1UL << mmu_psize_defs[psize].shift) - 1);
psize = pte_pagesize_index(mm, addr, pte); /* shutup gcc */
- } else
+ } else {
psize = pte_pagesize_index(mm, addr, pte);
+ /* Mask the address for the standard page size. If we
+ * have a 64k page kernel, but the hardware does not
+ * support 64k pages, this might be different from the
+ * hardware page size encoded in the slice table. */
+ addr &= PAGE_MASK;
+ }
- /* Mask the address for the correct page size */
- addr &= ~((1UL << mmu_psize_defs[psize].shift) - 1);
/* Build full vaddr */
if (!is_kernel_addr(addr)) {