[PATCH v4 07/10] sparc64: zero newly allocated IOMMU page tables

[Magnus Lindholm]

iopte_make_dummy() replaces only the physical page field, preserving
all attributes. Applying it to an uninitialized table leaves validity,
permissions, context and reserved bits dependent on prior page contents.

Zero the table allocation before installing dummy page addresses. Keep
iopte_make_dummy() unchanged for unmap callers that preserve attributes.

This initialization pattern is already present in the initial Git
import; the Fixes tag identifies its earliest recorded version.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Magnus Lindholm <linmag7@xxxxxxxxx>
---
 arch/sparc/kernel/iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
index a23105b64fb9..66aaafbf1621 100644
--- a/arch/sparc/kernel/iommu.c
+++ b/arch/sparc/kernel/iommu.c
@@ -130,7 +130,7 @@ int iommu_table_init(struct iommu *iommu, int tsbsize,
 
 	/* Now allocate and setup the IOMMU page table itself.  */
 	order = get_order(tsbsize);
-	page = alloc_pages_node(numa_node, GFP_KERNEL, order);
+	page = alloc_pages_node(numa_node, GFP_KERNEL | __GFP_ZERO, order);
 	if (!page) {
 		printk(KERN_ERR "IOMMU: Error, gfp(tsb) failed.\n");
 		goto out_free_dummy_page;
-- 
2.43.0