[PATCH v2] iommu/io-pgtable-arm: Check for v7s-incapable systems

[robin.murphy@arm.com (Robin Murphy)]

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>
---

Apparently, in my haste, I overlooked that not everything that can do
COMPILE_TEST also has a PHYS_OFFSET.

 drivers/iommu/io-pgtable-arm-v7s.c | 4 ++++
 1 file changed, 4 insertions(+)

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;
 
-- 
2.8.1.dirty