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-rw-r--r--arch/powerpc/kernel/iommu.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 961bb03413f3..0cfcf98aafca 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -501,6 +501,14 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
tbl->it_map = page_address(page);
memset(tbl->it_map, 0, sz);
+ /*
+ * Reserve page 0 so it will not be used for any mappings.
+ * This avoids buggy drivers that consider page 0 to be invalid
+ * to crash the machine or even lose data.
+ */
+ if (tbl->it_offset == 0)
+ set_bit(0, tbl->it_map);
+
tbl->it_hint = 0;
tbl->it_largehint = tbl->it_halfpoint;
spin_lock_init(&tbl->it_lock);