tlk_driver: propagate TLK error code to user-app

Bug 2186806
Tests Tested locally by turning NS DRAM ranges feature ON/OFF and testing
      userspace binaries

Change-Id: I52687f865cf205d158fbf2126c1bb0833ef772d2
Signed-off-by: Mihir Joshi <mihirj@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1784276
(cherry picked from commit e9dd22e4eddc803488d4f4d2315e23c1de9e2f01)
Reviewed-on: https://git-master.nvidia.com/r/1793791
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/security/tlk_driver/ote_comms.c b/security/tlk_driver/ote_comms.c
index 9b16565c5..71fb0f6ea 100644
--- a/security/tlk_driver/ote_comms.c
+++ b/security/tlk_driver/ote_comms.c
@@ -158,6 +158,7 @@ static void do_smc(struct te_request *request, struct tlk_device *dev)
 {
         uint32_t smc_args;
         uint32_t smc_params = 0;
+        uint32_t retval = 0;
 
         smc_args = (uintptr_t)request - (uintptr_t)dev->req_addr;
         if (request->params) {
@@ -165,7 +166,23 @@ static void do_smc(struct te_request *request, struct tlk_device *dev)
                         (uintptr_t)request->params - (uintptr_t)dev->req_addr;
         }
 
-        (void)tlk_send_smc(request->type, smc_args, smc_params);
+        retval = tlk_send_smc(request->type, smc_args, smc_params);
+
+        /**
+         * Check for return code from TLK kernel and propagate to NS userspace
+         *
+         * Under certain situations, TLK kernel may return an error code
+         * _without_ updating the shared request buffer.
+         *
+         * This could give a false impression to the user-app about status of
+         * the request (if default value of request->result is OTE_SUCCESS).
+         *
+         * Propagate the error code to NS user-app in case of such scenario.
+         */
+        if ((retval != OTE_SUCCESS) && (request->result == OTE_SUCCESS)) {
+                request->result = retval;
+                request->result_origin = OTE_RESULT_ORIGIN_KERNEL;
+        }
 }
 
 void tlk_restore_keyslots(void)