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/os/linux/ioctl_tsg.c b/drivers/gpu/nvgpu/os/linux/ioctl_tsg.c
index a26559f5..2f8cb3ae 100644
--- a/drivers/gpu/nvgpu/os/linux/ioctl_tsg.c
+++ b/drivers/gpu/nvgpu/os/linux/ioctl_tsg.c
@@ -361,6 +361,7 @@ static int gk20a_tsg_event_id_ctrl(struct gk20a *g, struct tsg_gk20a *tsg,
         if (args->event_id >= NVGPU_IOCTL_CHANNEL_EVENT_ID_MAX)
                 return -EINVAL;
 
+        nvgpu_speculation_barrier();
         switch (args->cmd) {
         case NVGPU_IOCTL_CHANNEL_EVENT_ID_CMD_ENABLE:
                 err = gk20a_tsg_event_id_enable(tsg, args->event_id, &fd);
@@ -572,6 +573,7 @@ static int gk20a_tsg_ioctl_read_single_sm_error_state(struct gk20a *g,
         if (args->record_size > 0) {
                 size_t write_size = sizeof(*sm_error_state);
 
+                nvgpu_speculation_barrier();
                 if (write_size > args->record_size)
                         write_size = args->record_size;