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, 2 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
index 989ee5c9..636d5714 100644
--- a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
@@ -3943,6 +3943,7 @@ int gr_gk20a_add_zbc(struct gk20a *g, struct gr_gk20a *gr,
         /* no endian swap ? */
 
         nvgpu_mutex_acquire(&gr->zbc_lock);
+        nvgpu_speculation_barrier();
         switch (zbc_val->type) {
         case GK20A_ZBC_TYPE_COLOR:
                 /* search existing tables */
@@ -4047,6 +4048,7 @@ int gr_gk20a_query_zbc(struct gk20a *g, struct gr_gk20a *gr,
         u32 index = query_params->index_size;
         u32 i;
 
+        nvgpu_speculation_barrier();
         switch (query_params->type) {
         case GK20A_ZBC_TYPE_INVALID:
                 query_params->index_size = GK20A_ZBC_TABLE_SIZE;