iommu/io-pgtable-arm: Check for v7s-incapable systems

On machines with no 32-bit addressable RAM whatsoever, we shouldn't
even touch the v7s format as it's never going to work.

Fixes: e5fc9753b1a8 ("iommu/io-pgtable: Add ARMv7 short descriptor support")
Reported-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index def8ca1c982d..f50e51c1a9c8 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -633,6 +633,10 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
 {
         struct arm_v7s_io_pgtable *data;
 
+#ifdef PHYS_OFFSET
+        if (upper_32_bits(PHYS_OFFSET))
+                return NULL;
+#endif
         if (cfg->ias > ARM_V7S_ADDR_BITS || cfg->oas > ARM_V7S_ADDR_BITS)
                 return NULL;