With hugepages, we store the hpte valid information in the pte page
whose address is stored in the second half of the PMD. Use a
write barrier to make sure clearing pmd busy bit and updating
hpte valid info are ordered properly.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
arch/powerpc/mm/hugepage-hash64.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/hugepage-hash64.c
b/arch/powerpc/mm/hugepage-hash64.c
index 826893fcb3a7..11f9a37ca2c6 100644
--- a/arch/powerpc/mm/hugepage-hash64.c
+++ b/arch/powerpc/mm/hugepage-hash64.c
@@ -172,8 +172,11 @@ repeat:
mark_hpte_slot_valid(hpte_slot_array, index, slot);
}
/*
- * No need to use ldarx/stdcx here
+ * The hpte valid is stored in the pgtable whose address is in the
+ * second half of the PMD. Order this against clearing of the busy bit
in
+ * huge pmd.
*/
+ smp_wmb();
*pmdp = __pmd(new_pmd & ~_PAGE_BUSY);
return 0;
}
--
1.9.1
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