iommu: add IOMMU_EXEC flag for safely allowing XN mappings

Whilst most IOMMU mappings should probably be non-executable, there
may be cases (HSA?) where executable mappings are required.

This patch introduces a new mapping flag, IOMMU_EXEC, to indicate that
the mapping should be mapped as executable.

Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index a444c79..709a697 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -24,9 +24,10 @@
 #include <linux/types.h>
 #include <trace/events/iommu.h>
 
-#define IOMMU_READ     (1)
-#define IOMMU_WRITE    (2)
-#define IOMMU_CACHE    (4) /* DMA cache coherency */
+#define IOMMU_READ     (1 << 0)
+#define IOMMU_WRITE    (1 << 1)
+#define IOMMU_CACHE    (1 << 2) /* DMA cache coherency */
+#define IOMMU_EXEC     (1 << 3)
 
 struct iommu_ops;
 struct iommu_group;