[PATCH v3 12/20] gpu: host1x: Forbid relocation address shifting in the firewall

[Dmitry Osipenko]

Incorrectly shifted relocation address will cause a lower memory corruption
and likely a hang on a write or a read of an arbitrary data in case of IOMMU
absence. As of now, there is no known use for the address shifting and adding
a proper shifts / sizes validation is a much more work. Let's forbid shifts
in the firewall till a proper validation is implemented.

Signed-off-by: Dmitry Osipenko <digetx at gmail.com>
Reviewed-by: Erik Faye-Lund <kusmabite at gmail.com>
Reviewed-by: Mikko Perttunen <mperttunen at nvidia.com>
---
 drivers/gpu/host1x/job.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c
index 4208329ca2af..a911de6386b4 100644
--- a/drivers/gpu/host1x/job.c
+++ b/drivers/gpu/host1x/job.c
@@ -330,6 +330,10 @@ static bool check_reloc(struct host1x_reloc *reloc, struct host1x_bo *cmdbuf,
 	if (reloc->cmdbuf.bo != cmdbuf || reloc->cmdbuf.offset != offset)
 		return false;
 
+	/* relocation shift value validation isn't implemented yet */
+	if (reloc->shift)
+		return false;
+
 	return true;
 }
 
-- 
2.13.0