gpu: nvgpu: add speculative barrier

Data can be speculativerly stored and
code flow can be hijacked.

To mitigate this problem insert a
speculation barrier.

Bug 200447167

Change-Id: Ia865ff2add8b30de49aa970715625b13e8f71c08
Signed-off-by: Ranjanikar Nikhil Prabhakarrao <rprabhakarra@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1972221
(cherry picked from commit f0762ed4831b3fe6cc953a4a4ec26c2537dcb69f)
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/1996052
Reviewed-by: automaticguardword <automaticguardword@nvidia.com>
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit
Tested-by: Deepak Nibade <dnibade@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gp10b/gr_gp10b.c b/drivers/gpu/nvgpu/gp10b/gr_gp10b.c
index 4b42678f..2bcb08a4 100644
--- a/drivers/gpu/nvgpu/gp10b/gr_gp10b.c
+++ b/drivers/gpu/nvgpu/gp10b/gr_gp10b.c
@@ -52,6 +52,7 @@ bool gr_gp10b_is_valid_class(struct gk20a *g, u32 class_num)
 {
         bool valid = false;
 
+        nvgpu_speculation_barrier();
         switch (class_num) {
         case PASCAL_COMPUTE_A:
         case PASCAL_A: