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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2015-09-15 12:30:08 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2015-09-16 22:06:03 +1000
commit36b35d5d807b7e57aff7d08e63de8b17731ee211 (patch)
tree1629b6259078a9ef2b0e6eaeeee930a0fb456e57 /arch
parent655471f54c2e395ba29ae4156ba0f49928177cc1 (diff)
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powerpc/mm: Recompute hash value after a failed update
If we had secondary hash flag set, we ended up modifying hash value in the updatepp code path. Hence with a failed updatepp we will be using a wrong hash value for the following hash insert. Fix this by recomputing hash before insert. Without this patch we can end up with using wrong slot number in linux pte. That can result in us missing an hash pte update or invalidate which can cause memory corruption or even machine check. Fixes: 6d492ecc6489 ("powerpc/THP: Add code to handle HPTE faults for hugepages") Cc: stable@vger.kernel.org # v3.11+ Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Reviewed-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/mm/hugepage-hash64.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c
index 43dafb9d6a46..4d87122cf6a7 100644
--- a/arch/powerpc/mm/hugepage-hash64.c
+++ b/arch/powerpc/mm/hugepage-hash64.c
@@ -85,7 +85,6 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
BUG_ON(index >= 4096);
vpn = hpt_vpn(ea, vsid, ssize);
- hash = hpt_hash(vpn, shift, ssize);
hpte_slot_array = get_hpte_slot_array(pmdp);
if (psize == MMU_PAGE_4K) {
/*
@@ -101,6 +100,7 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
valid = hpte_valid(hpte_slot_array, index);
if (valid) {
/* update the hpte bits */
+ hash = hpt_hash(vpn, shift, ssize);
hidx = hpte_hash_index(hpte_slot_array, index);
if (hidx & _PTEIDX_SECONDARY)
hash = ~hash;
@@ -126,6 +126,7 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
if (!valid) {
unsigned long hpte_group;
+ hash = hpt_hash(vpn, shift, ssize);
/* insert new entry */
pa = pmd_pfn(__pmd(old_pmd)) << PAGE_SHIFT;
new_pmd |= _PAGE_HASHPTE;