diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/AArch64/RngDxe.c b/SecurityPkg/RandomNumberGenerator/RngDxe/AArch64/RngDxe.c
index 6d989f7ea3..f9c740d761 100644
--- a/SecurityPkg/RandomNumberGenerator/RngDxe/AArch64/RngDxe.c
+++ b/SecurityPkg/RandomNumberGenerator/RngDxe/AArch64/RngDxe.c
@@ -23,7 +23,6 @@
 #include <Library/BaseLib.h>
 #include <Library/BaseMemoryLib.h>
 #include <Library/UefiBootServicesTableLib.h>
-#include <Library/TimerLib.h>
 #include <Protocol/Rng.h>
 
 #include "RngDxeInternals.h"
@@ -61,7 +60,7 @@ RngGetRNG (
 {
   EFI_STATUS  Status;
 
-  if ((RNGValueLength == 0) || (RNGValue == NULL)) {
+  if ((This == NULL) || (RNGValueLength == 0) || (RNGValue == NULL)) {
     return EFI_INVALID_PARAMETER;
   }
 
diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RngDxe.c b/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RngDxe.c
index b2d2236380..8f5d8e740f 100644
--- a/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RngDxe.c
+++ b/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RngDxe.c
@@ -59,7 +59,7 @@ RngGetRNG (
 {
   EFI_STATUS  Status;
 
-  if ((RNGValueLength == 0) || (RNGValue == NULL)) {
+  if ((This == NULL) || (RNGValueLength == 0) || (RNGValue == NULL)) {
     return EFI_INVALID_PARAMETER;
   }
 
diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.c b/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.c
index 6608ca8804..d7905a7f4d 100644
--- a/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.c
+++ b/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.c
@@ -23,7 +23,6 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include <Library/BaseMemoryLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/RngLib.h>
-#include <Library/TimerLib.h>
 #include <Protocol/Rng.h>
 
 #include "RngDxeInternals.h"
@@ -72,7 +71,7 @@ RngDriverEntry (
 }
 
 /**
-  Calls RDRAND to fill a buffer of arbitrary size with random bytes.
+  Runs CPU RNG instruction to fill a buffer of arbitrary size with random bytes.
 
   @param[in]   Length        Size of the buffer, in bytes,  to fill with.
   @param[out]  RandBuffer    Pointer to the buffer to store the random result.