iommu/arm-smmu: change IOMMU_EXEC to IOMMU_NOEXEC

Exposing the XN flag of the SMMU driver as IOMMU_NOEXEC instead of
IOMMU_EXEC makes it enforceable, since for IOMMUs that don't support
the XN flag pages will always be executable.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>

2 files changed, 6 insertions, 5 deletions

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 60558f794922..566c1769d9bd 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1281,7 +1281,7 @@ static int arm_smmu_alloc_init_pte(struct arm_smmu_device *smmu, pmd_t *pmd,
                                    unsigned long pfn, int prot, int stage)
 {
         pte_t *pte, *start;
-        pteval_t pteval = ARM_SMMU_PTE_PAGE | ARM_SMMU_PTE_AF | ARM_SMMU_PTE_XN;
+        pteval_t pteval = ARM_SMMU_PTE_PAGE | ARM_SMMU_PTE_AF;
 
         if (pmd_none(*pmd)) {
                 /* Allocate a new set of tables */
@@ -1315,10 +1315,11 @@ static int arm_smmu_alloc_init_pte(struct arm_smmu_device *smmu, pmd_t *pmd,
                         pteval |= ARM_SMMU_PTE_MEMATTR_NC;
         }
 
+        if (prot & IOMMU_NOEXEC)
+                pteval |= ARM_SMMU_PTE_XN;
+
         /* If no access, create a faulting entry to avoid TLB fills */
-        if (prot & IOMMU_EXEC)
-                pteval &= ~ARM_SMMU_PTE_XN;
-        else if (!(prot & (IOMMU_READ | IOMMU_WRITE)))
+        if (!(prot & (IOMMU_READ | IOMMU_WRITE)))
                 pteval &= ~ARM_SMMU_PTE_PAGE;
 
         pteval |= ARM_SMMU_PTE_SH_IS;
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index e6a7c9ff72f2..f47383a05d34 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -27,7 +27,7 @@
 #define IOMMU_READ      (1 << 0)
 #define IOMMU_WRITE     (1 << 1)
 #define IOMMU_CACHE     (1 << 2) /* DMA cache coherency */
-#define IOMMU_EXEC      (1 << 3)
+#define IOMMU_NOEXEC    (1 << 3)
 
 struct iommu_ops;
 struct iommu_group;