This patch looks good to me.

Reviewed-by: Sami Mujawar <sami.muja...@arm.com>

Regards,

Sami Mujawar


On 10/05/2021 10:53 PM, Rebecca Cran wrote:
AARCH64 support has been added to BaseRngLib via the optional
ARMv8.5 FEAT_RNG.

Refactor RngDxe to support AARCH64, note support for it in the
VALID_ARCHITECTURES line of RngDxe.inf and enable it in SecurityPkg.dsc.

Signed-off-by: Rebecca Cran <rebe...@nuviainc.com>
---
  SecurityPkg/SecurityPkg.dec                                   |   2 +
  SecurityPkg/SecurityPkg.dsc                                   |  11 +-
  SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.inf           |  24 ++-
  SecurityPkg/RandomNumberGenerator/RngDxe/{ => Rand}/AesCore.h |   0
  SecurityPkg/RandomNumberGenerator/RngDxe/{ => Rand}/RdRand.h  |  17 --
  SecurityPkg/RandomNumberGenerator/RngDxe/RngDxeInternals.h    | 117 
++++++++++++++
  SecurityPkg/RandomNumberGenerator/RngDxe/AArch64/RngDxe.c     | 127 
+++++++++++++++
  SecurityPkg/RandomNumberGenerator/RngDxe/{ => Rand}/AesCore.c |   0
  SecurityPkg/RandomNumberGenerator/RngDxe/{ => Rand}/RdRand.c  |  45 +-----
  SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RngDxe.c        | 146 
+++++++++++++++++
  SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.c             | 170 
++++++++------------
  11 files changed, 483 insertions(+), 176 deletions(-)

diff --git a/SecurityPkg/SecurityPkg.dec b/SecurityPkg/SecurityPkg.dec
index dfbbb0365a2b..4001650fa28e 100644
--- a/SecurityPkg/SecurityPkg.dec
+++ b/SecurityPkg/SecurityPkg.dec
@@ -297,6 +297,8 @@ [PcdsFixedAtBuild, PcdsPatchableInModule]
    
gEfiSecurityPkgTokenSpaceGuid.PcdStatusCodeFvVerificationPass|0x0303100A|UINT32|0x00010030
    
gEfiSecurityPkgTokenSpaceGuid.PcdStatusCodeFvVerificationFail|0x0303100B|UINT32|0x00010031

+  
gEfiSecurityPkgTokenSpaceGuid.PcdCpuRngSupportedAlgorithm|{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00}|VOID*|0x00010032
+
  [PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
    ## Image verification policy for OptionRom. Only following values are 
valid:<BR><BR>
    #  NOTE: Do NOT use 0x5 and 0x2 since it violates the UEFI specification and has 
been removed.<BR>
diff --git a/SecurityPkg/SecurityPkg.dsc b/SecurityPkg/SecurityPkg.dsc
index 12ccd1634941..bd4b810bce61 100644
--- a/SecurityPkg/SecurityPkg.dsc
+++ b/SecurityPkg/SecurityPkg.dsc
@@ -259,6 +259,12 @@ [Components]
  [Components.IA32, Components.X64, Components.ARM, Components.AARCH64]
    SecurityPkg/Library/AuthVariableLib/AuthVariableLib.inf

+[Components.IA32, Components.X64, Components.AARCH64]
+  #
+  # Random Number Generator
+  #
+  SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.inf
+
  [Components.IA32, Components.X64]
    
SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf

@@ -334,11 +340,6 @@ [Components.IA32, Components.X64]
    
SecurityPkg/Library/SmmTcg2PhysicalPresenceLib/SmmTcg2PhysicalPresenceLib.inf
    
SecurityPkg/Library/SmmTcg2PhysicalPresenceLib/StandaloneMmTcg2PhysicalPresenceLib.inf

-  #
-  # Random Number Generator
-  #
-  SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.inf
-
    #
    # Opal Password solution
    #
diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.inf 
b/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.inf
index 99d6f6b35fc2..f3300971993f 100644
--- a/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.inf
+++ b/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.inf
@@ -26,15 +26,22 @@ [Defines]
  #
  # The following information is for reference only and not required by the 
build tools.
  #
-#  VALID_ARCHITECTURES           = IA32 X64
+#  VALID_ARCHITECTURES           = IA32 X64 AARCH64
  #

  [Sources.common]
    RngDxe.c
-  RdRand.c
-  RdRand.h
-  AesCore.c
-  AesCore.h
+  RngDxeInternals.h
+
+[Sources.IA32, Sources.X64]
+  Rand/RngDxe.c
+  Rand/RdRand.c
+  Rand/RdRand.h
+  Rand/AesCore.c
+  Rand/AesCore.h
+
+[Sources.AARCH64]
+  AArch64/RngDxe.c

  [Packages]
    MdePkg/MdePkg.dec
@@ -50,12 +57,19 @@ [LibraryClasses]
    RngLib

  [Guids]
+  gEfiRngAlgorithmSp80090Hash256Guid  ## SOMETIMES_PRODUCES    ## GUID        
# Unique ID of the algorithm for RNG
+  gEfiRngAlgorithmSp80090Hmac256Guid  ## SOMETIMES_PRODUCES    ## GUID        
# Unique ID of the algorithm for RNG
    gEfiRngAlgorithmSp80090Ctr256Guid   ## SOMETIMES_PRODUCES    ## GUID        
# Unique ID of the algorithm for RNG
+  gEfiRngAlgorithmX9313DesGuid        ## SOMETIMES_PRODUCES    ## GUID        
# Unique ID of the algorithm for RNG
+  gEfiRngAlgorithmX931AesGuid         ## SOMETIMES_PRODUCES    ## GUID        
# Unique ID of the algorithm for RNG
    gEfiRngAlgorithmRaw                 ## SOMETIMES_PRODUCES    ## GUID        
# Unique ID of the algorithm for RNG

  [Protocols]
    gEfiRngProtocolGuid                ## PRODUCES

+[Pcd]
+  gEfiSecurityPkgTokenSpaceGuid.PcdCpuRngSupportedAlgorithm      ## CONSUMES
+
  [Depex]
    TRUE

diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/AesCore.h 
b/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/AesCore.h
similarity index 100%
rename from SecurityPkg/RandomNumberGenerator/RngDxe/AesCore.h
rename to SecurityPkg/RandomNumberGenerator/RngDxe/Rand/AesCore.h
diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/RdRand.h 
b/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RdRand.h
similarity index 72%
rename from SecurityPkg/RandomNumberGenerator/RngDxe/RdRand.h
rename to SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RdRand.h
index 12ab1f34ec6d..072378e062e7 100644
--- a/SecurityPkg/RandomNumberGenerator/RngDxe/RdRand.h
+++ b/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RdRand.h
@@ -23,23 +23,6 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
  #include <Library/TimerLib.h>
  #include <Protocol/Rng.h>

-/**
-  Calls RDRAND 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.
-
-  @retval EFI_SUCCESS        Random bytes generation succeeded.
-  @retval EFI_NOT_READY      Failed to request random bytes.
-
-**/
-EFI_STATUS
-EFIAPI
-RdRandGetBytes (
-  IN UINTN         Length,
-  OUT UINT8        *RandBuffer
-  );
-
  /**
    Generate high-quality entropy source through RDRAND.

diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxeInternals.h 
b/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxeInternals.h
new file mode 100644
index 000000000000..2660ed5875e0
--- /dev/null
+++ b/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxeInternals.h
@@ -0,0 +1,117 @@
+/** @file
+  Function prototypes for UEFI Random Number Generator protocol support.
+
+  Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef RNGDXE_INTERNALS_H_
+#define RNGDXE_INTERNALS_H_
+
+/**
+  Returns information about the random number generation implementation.
+
+  @param[in]     This                 A pointer to the EFI_RNG_PROTOCOL 
instance.
+  @param[in,out] RNGAlgorithmListSize On input, the size in bytes of 
RNGAlgorithmList.
+                                      On output with a return code of 
EFI_SUCCESS, the size
+                                      in bytes of the data returned in 
RNGAlgorithmList. On output
+                                      with a return code of 
EFI_BUFFER_TOO_SMALL,
+                                      the size of RNGAlgorithmList required to 
obtain the list.
+  @param[out] RNGAlgorithmList        A caller-allocated memory buffer filled 
by the driver
+                                      with one EFI_RNG_ALGORITHM element for 
each supported
+                                      RNG algorithm. The list must not change 
across multiple
+                                      calls to the same driver. The first 
algorithm in the list
+                                      is the default algorithm for the driver.
+
+  @retval EFI_SUCCESS                 The RNG algorithm list was returned 
successfully.
+  @retval EFI_UNSUPPORTED             The services is not supported by this 
driver.
+  @retval EFI_DEVICE_ERROR            The list of algorithms could not be 
retrieved due to a
+                                      hardware or firmware error.
+  @retval EFI_INVALID_PARAMETER       One or more of the parameters are 
incorrect.
+  @retval EFI_BUFFER_TOO_SMALL        The buffer RNGAlgorithmList is too small 
to hold the result.
+
+**/
+EFI_STATUS
+EFIAPI
+RngGetInfo (
+  IN EFI_RNG_PROTOCOL             *This,
+  IN OUT UINTN                    *RNGAlgorithmListSize,
+  OUT EFI_RNG_ALGORITHM           *RNGAlgorithmList
+  );
+
+/**
+  Produces and returns an RNG value using either the default or specified RNG 
algorithm.
+
+  @param[in]  This                    A pointer to the EFI_RNG_PROTOCOL 
instance.
+  @param[in]  RNGAlgorithm            A pointer to the EFI_RNG_ALGORITHM that 
identifies the RNG
+                                      algorithm to use. May be NULL in which 
case the function will
+                                      use its default RNG algorithm.
+  @param[in]  RNGValueLength          The length in bytes of the memory buffer 
pointed to by
+                                      RNGValue. The driver shall return 
exactly this numbers of bytes.
+  @param[out] RNGValue                A caller-allocated memory buffer filled 
by the driver with the
+                                      resulting RNG value.
+
+  @retval EFI_SUCCESS                 The RNG value was returned successfully.
+  @retval EFI_UNSUPPORTED             The algorithm specified by RNGAlgorithm 
is not supported by
+                                      this driver.
+  @retval EFI_DEVICE_ERROR            An RNG value could not be retrieved due 
to a hardware or
+                                      firmware error.
+  @retval EFI_NOT_READY               There is not enough random data 
available to satisfy the length
+                                      requested by RNGValueLength.
+  @retval EFI_INVALID_PARAMETER       RNGValue is NULL or RNGValueLength is 
zero.
+
+**/
+EFI_STATUS
+EFIAPI
+RngGetRNG (
+  IN EFI_RNG_PROTOCOL            *This,
+  IN EFI_RNG_ALGORITHM           *RNGAlgorithm, OPTIONAL
+  IN UINTN                       RNGValueLength,
+  OUT UINT8                      *RNGValue
+  );
+
+/**
+  Returns information about the random number generation implementation.
+
+  @param[in,out] RNGAlgorithmListSize On input, the size in bytes of 
RNGAlgorithmList.
+                                      On output with a return code of 
EFI_SUCCESS, the size
+                                      in bytes of the data returned in 
RNGAlgorithmList. On output
+                                      with a return code of 
EFI_BUFFER_TOO_SMALL,
+                                      the size of RNGAlgorithmList required to 
obtain the list.
+  @param[out] RNGAlgorithmList        A caller-allocated memory buffer filled 
by the driver
+                                      with one EFI_RNG_ALGORITHM element for 
each supported
+                                      RNG algorithm. The list must not change 
across multiple
+                                      calls to the same driver. The first 
algorithm in the list
+                                      is the default algorithm for the driver.
+
+  @retval EFI_SUCCESS                 The RNG algorithm list was returned 
successfully.
+  @retval EFI_BUFFER_TOO_SMALL        The buffer RNGAlgorithmList is too small 
to hold the result.
+
+**/
+UINTN
+EFIAPI
+ArchGetSupportedRngAlgorithms (
+  IN OUT UINTN                     *RNGAlgorithmListSize,
+  OUT    EFI_RNG_ALGORITHM         *RNGAlgorithmList
+  );
+
+/**
+  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.
+
+  @retval EFI_SUCCESS        Random bytes generation succeeded.
+  @retval EFI_NOT_READY      Failed to request random bytes.
+
+**/
+EFI_STATUS
+EFIAPI
+RngGetBytes (
+  IN UINTN         Length,
+  OUT UINT8        *RandBuffer
+  );
+
+#endif  // RNGDXE_INTERNALS_H_
diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/AArch64/RngDxe.c 
b/SecurityPkg/RandomNumberGenerator/RngDxe/AArch64/RngDxe.c
new file mode 100644
index 000000000000..2810a9eb94ad
--- /dev/null
+++ b/SecurityPkg/RandomNumberGenerator/RngDxe/AArch64/RngDxe.c
@@ -0,0 +1,127 @@
+/** @file
+  RNG Driver to produce the UEFI Random Number Generator protocol.
+
+  The driver will use the RNDR instruction to produce random numbers.
+
+  RNG Algorithms defined in UEFI 2.4:
+   - EFI_RNG_ALGORITHM_SP800_90_CTR_256_GUID
+   - EFI_RNG_ALGORITHM_RAW                    - Unsupported
+   - EFI_RNG_ALGORITHM_SP800_90_HMAC_256_GUID
+   - EFI_RNG_ALGORITHM_SP800_90_HASH_256_GUID
+   - EFI_RNG_ALGORITHM_X9_31_3DES_GUID        - Unsupported
+   - EFI_RNG_ALGORITHM_X9_31_AES_GUID         - Unsupported
+
+  Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
+  Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
+  (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/TimerLib.h>
+#include <Protocol/Rng.h>
+
+#include "RngDxeInternals.h"
+
+/**
+  Produces and returns an RNG value using either the default or specified RNG 
algorithm.
+
+  @param[in]  This                    A pointer to the EFI_RNG_PROTOCOL 
instance.
+  @param[in]  RNGAlgorithm            A pointer to the EFI_RNG_ALGORITHM that 
identifies the RNG
+                                      algorithm to use. May be NULL in which 
case the function will
+                                      use its default RNG algorithm.
+  @param[in]  RNGValueLength          The length in bytes of the memory buffer 
pointed to by
+                                      RNGValue. The driver shall return 
exactly this numbers of bytes.
+  @param[out] RNGValue                A caller-allocated memory buffer filled 
by the driver with the
+                                      resulting RNG value.
+
+  @retval EFI_SUCCESS                 The RNG value was returned successfully.
+  @retval EFI_UNSUPPORTED             The algorithm specified by RNGAlgorithm 
is not supported by
+                                      this driver.
+  @retval EFI_DEVICE_ERROR            An RNG value could not be retrieved due 
to a hardware or
+                                      firmware error.
+  @retval EFI_NOT_READY               There is not enough random data 
available to satisfy the length
+                                      requested by RNGValueLength.
+  @retval EFI_INVALID_PARAMETER       RNGValue is NULL or RNGValueLength is 
zero.
+
+**/
+EFI_STATUS
+EFIAPI
+RngGetRNG (
+  IN EFI_RNG_PROTOCOL            *This,
+  IN EFI_RNG_ALGORITHM           *RNGAlgorithm, OPTIONAL
+  IN UINTN                       RNGValueLength,
+  OUT UINT8                      *RNGValue
+  )
+{
+  EFI_STATUS    Status;
+
+  if ((RNGValueLength == 0) || (RNGValue == NULL)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  if (RNGAlgorithm == NULL) {
+    //
+    // Use the default RNG algorithm if RNGAlgorithm is NULL.
+    //
+    RNGAlgorithm = PcdGetPtr (PcdCpuRngSupportedAlgorithm);
+  }
+
+  if (CompareGuid (RNGAlgorithm, PcdGetPtr (PcdCpuRngSupportedAlgorithm))) {
+    Status = RngGetBytes (RNGValueLength, RNGValue);
+    return Status;
+  }
+
+  //
+  // Other algorithms are unsupported by this driver.
+  //
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Returns information about the random number generation implementation.
+
+  @param[in,out] RNGAlgorithmListSize On input, the size in bytes of 
RNGAlgorithmList.
+                                      On output with a return code of 
EFI_SUCCESS, the size
+                                      in bytes of the data returned in 
RNGAlgorithmList. On output
+                                      with a return code of 
EFI_BUFFER_TOO_SMALL,
+                                      the size of RNGAlgorithmList required to 
obtain the list.
+  @param[out] RNGAlgorithmList        A caller-allocated memory buffer filled 
by the driver
+                                      with one EFI_RNG_ALGORITHM element for 
each supported
+                                      RNG algorithm. The list must not change 
across multiple
+                                      calls to the same driver. The first 
algorithm in the list
+                                      is the default algorithm for the driver.
+
+  @retval EFI_SUCCESS                 The RNG algorithm list was returned 
successfully.
+  @retval EFI_BUFFER_TOO_SMALL        The buffer RNGAlgorithmList is too small 
to hold the result.
+
+**/
+UINTN
+EFIAPI
+ArchGetSupportedRngAlgorithms (
+  IN OUT UINTN                     *RNGAlgorithmListSize,
+  OUT    EFI_RNG_ALGORITHM         *RNGAlgorithmList
+  )
+{
+  UINTN RequiredSize;
+  EFI_RNG_ALGORITHM *CpuRngSupportedAlgorithm;
+
+  RequiredSize = sizeof (EFI_RNG_ALGORITHM);
+
+  if (*RNGAlgorithmListSize < RequiredSize) {
+    *RNGAlgorithmListSize = RequiredSize;
+    return EFI_BUFFER_TOO_SMALL;
+  }
+
+  CpuRngSupportedAlgorithm = PcdGetPtr (PcdCpuRngSupportedAlgorithm);
+
+  CopyMem(&RNGAlgorithmList[0], CpuRngSupportedAlgorithm, sizeof 
(EFI_RNG_ALGORITHM));
+
+  *RNGAlgorithmListSize = RequiredSize;
+  return EFI_SUCCESS;
+}
+
diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/AesCore.c 
b/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/AesCore.c
similarity index 100%
rename from SecurityPkg/RandomNumberGenerator/RngDxe/AesCore.c
rename to SecurityPkg/RandomNumberGenerator/RngDxe/Rand/AesCore.c
diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/RdRand.c 
b/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RdRand.c
similarity index 71%
rename from SecurityPkg/RandomNumberGenerator/RngDxe/RdRand.c
rename to SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RdRand.c
index e7dd5ab18111..83025a47d43d 100644
--- a/SecurityPkg/RandomNumberGenerator/RngDxe/RdRand.c
+++ b/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RdRand.c
@@ -8,48 +8,9 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
  **/
  #include <Library/RngLib.h>

-#include "RdRand.h"
  #include "AesCore.h"
-
-/**
-  Calls RDRAND 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.
-
-  @retval EFI_SUCCESS        Random bytes generation succeeded.
-  @retval EFI_NOT_READY      Failed to request random bytes.
-
-**/
-EFI_STATUS
-EFIAPI
-RdRandGetBytes (
-  IN UINTN         Length,
-  OUT UINT8        *RandBuffer
-  )
-{
-  BOOLEAN     IsRandom;
-  UINT64      TempRand[2];
-
-  while (Length > 0) {
-    IsRandom = GetRandomNumber128 (TempRand);
-    if (!IsRandom) {
-      return EFI_NOT_READY;
-    }
-    if (Length >= sizeof (TempRand)) {
-      WriteUnaligned64 ((UINT64*)RandBuffer, TempRand[0]);
-      RandBuffer += sizeof (UINT64);
-      WriteUnaligned64 ((UINT64*)RandBuffer, TempRand[1]);
-      RandBuffer += sizeof (UINT64);
-      Length -= sizeof (TempRand);
-    } else {
-      CopyMem (RandBuffer, TempRand, Length);
-      Length = 0;
-    }
-  }
-
-  return EFI_SUCCESS;
-}
+#include "RdRand.h"
+#include "RngDxeInternals.h"

  /**
    Creates a 128bit random value that is fully forward and backward prediction 
resistant,
@@ -92,7 +53,7 @@ RdRandGetSeed128 (
    //
    for (Index = 0; Index < 32; Index++) {
      MicroSecondDelay (10);
-    Status = RdRandGetBytes (16, RandByte);
+    Status = RngGetBytes (16, RandByte);
      if (EFI_ERROR (Status)) {
        return Status;
      }
diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RngDxe.c 
b/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RngDxe.c
new file mode 100644
index 000000000000..6b628a9f8bc6
--- /dev/null
+++ b/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RngDxe.c
@@ -0,0 +1,146 @@
+/** @file
+  RNG Driver to produce the UEFI Random Number Generator protocol.
+
+  The driver will use the new RDRAND instruction to produce high-quality, 
high-performance
+  entropy and random number.
+
+  RNG Algorithms defined in UEFI 2.4:
+   - EFI_RNG_ALGORITHM_SP800_90_CTR_256_GUID  - Supported
+     (RDRAND implements a hardware NIST SP800-90 AES-CTR-256 based DRBG)
+   - EFI_RNG_ALGORITHM_RAW                    - Supported
+     (Structuring RDRAND invocation can be guaranteed as high-quality entropy 
source)
+   - EFI_RNG_ALGORITHM_SP800_90_HMAC_256_GUID - Unsupported
+   - EFI_RNG_ALGORITHM_SP800_90_HASH_256_GUID - Unsupported
+   - EFI_RNG_ALGORITHM_X9_31_3DES_GUID        - Unsupported
+   - EFI_RNG_ALGORITHM_X9_31_AES_GUID         - Unsupported
+
+  Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
+  (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include "RdRand.h"
+#include "RngDxeInternals.h"
+
+/**
+  Produces and returns an RNG value using either the default or specified RNG 
algorithm.
+
+  @param[in]  This                    A pointer to the EFI_RNG_PROTOCOL 
instance.
+  @param[in]  RNGAlgorithm            A pointer to the EFI_RNG_ALGORITHM that 
identifies the RNG
+                                      algorithm to use. May be NULL in which 
case the function will
+                                      use its default RNG algorithm.
+  @param[in]  RNGValueLength          The length in bytes of the memory buffer 
pointed to by
+                                      RNGValue. The driver shall return 
exactly this numbers of bytes.
+  @param[out] RNGValue                A caller-allocated memory buffer filled 
by the driver with the
+                                      resulting RNG value.
+
+  @retval EFI_SUCCESS                 The RNG value was returned successfully.
+  @retval EFI_UNSUPPORTED             The algorithm specified by RNGAlgorithm 
is not supported by
+                                      this driver.
+  @retval EFI_DEVICE_ERROR            An RNG value could not be retrieved due 
to a hardware or
+                                      firmware error.
+  @retval EFI_NOT_READY               There is not enough random data 
available to satisfy the length
+                                      requested by RNGValueLength.
+  @retval EFI_INVALID_PARAMETER       RNGValue is NULL or RNGValueLength is 
zero.
+
+**/
+EFI_STATUS
+EFIAPI
+RngGetRNG (
+  IN EFI_RNG_PROTOCOL            *This,
+  IN EFI_RNG_ALGORITHM           *RNGAlgorithm, OPTIONAL
+  IN UINTN                       RNGValueLength,
+  OUT UINT8                      *RNGValue
+  )
+{
+  EFI_STATUS    Status;
+
+  if ((RNGValueLength == 0) || (RNGValue == NULL)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  Status = EFI_UNSUPPORTED;
+  if (RNGAlgorithm == NULL) {
+    //
+    // Use the default RNG algorithm if RNGAlgorithm is NULL.
+    //
+    RNGAlgorithm = &gEfiRngAlgorithmSp80090Ctr256Guid;
+  }
+
+  //
+  // NIST SP800-90-AES-CTR-256 supported by RDRAND
+  //
+  if (CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmSp80090Ctr256Guid)) {
+    Status = RngGetBytes (RNGValueLength, RNGValue);
+    return Status;
+  }
+
+  //
+  // The "raw" algorithm is intended to provide entropy directly
+  //
+  if (CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmRaw)) {
+    //
+    // When a DRBG is used on the output of a entropy source,
+    // its security level must be at least 256 bits according to UEFI Spec.
+    //
+    if (RNGValueLength < 32) {
+      return EFI_INVALID_PARAMETER;
+    }
+
+    Status = RdRandGenerateEntropy (RNGValueLength, RNGValue);
+    return Status;
+  }
+
+  //
+  // Other algorithms were unsupported by this driver.
+  //
+  return Status;
+}
+
+/**
+  Returns information about the random number generation implementation.
+
+  @param[in,out] RNGAlgorithmListSize On input, the size in bytes of 
RNGAlgorithmList.
+                                      On output with a return code of 
EFI_SUCCESS, the size
+                                      in bytes of the data returned in 
RNGAlgorithmList. On output
+                                      with a return code of 
EFI_BUFFER_TOO_SMALL,
+                                      the size of RNGAlgorithmList required to 
obtain the list.
+  @param[out] RNGAlgorithmList        A caller-allocated memory buffer filled 
by the driver
+                                      with one EFI_RNG_ALGORITHM element for 
each supported
+                                      RNG algorithm. The list must not change 
across multiple
+                                      calls to the same driver. The first 
algorithm in the list
+                                      is the default algorithm for the driver.
+
+  @retval EFI_SUCCESS                 The RNG algorithm list was returned 
successfully.
+  @retval EFI_BUFFER_TOO_SMALL        The buffer RNGAlgorithmList is too small 
to hold the result.
+
+**/
+UINTN
+EFIAPI
+ArchGetSupportedRngAlgorithms (
+  IN OUT UINTN                     *RNGAlgorithmListSize,
+  OUT    EFI_RNG_ALGORITHM         *RNGAlgorithmList
+  )
+{
+  UINTN RequiredSize;
+  EFI_RNG_ALGORITHM *CpuRngSupportedAlgorithm;
+
+  RequiredSize = 2 * sizeof (EFI_RNG_ALGORITHM);
+
+  if (*RNGAlgorithmListSize < RequiredSize) {
+    *RNGAlgorithmListSize = RequiredSize;
+    return EFI_BUFFER_TOO_SMALL;
+  }
+
+  CpuRngSupportedAlgorithm = PcdGetPtr (PcdCpuRngSupportedAlgorithm);
+
+  CopyMem(&RNGAlgorithmList[0], CpuRngSupportedAlgorithm, sizeof 
(EFI_RNG_ALGORITHM));
+
+  // x86 platforms also support EFI_RNG_ALGORITHM_RAW via RDSEED
+  CopyMem(&RNGAlgorithmList[1], &gEfiRngAlgorithmRaw, sizeof 
(EFI_RNG_ALGORITHM));
+
+  *RNGAlgorithmListSize = RequiredSize;
+  return EFI_SUCCESS;
+}
+
diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.c 
b/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.c
index 13d3dbd0bfbe..b959c70536ea 100644
--- a/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.c
+++ b/SecurityPkg/RandomNumberGenerator/RngDxe/RngDxe.c
@@ -1,34 +1,32 @@
  /** @file
    RNG Driver to produce the UEFI Random Number Generator protocol.

-  The driver will use the new RDRAND instruction to produce high-quality, 
high-performance
-  entropy and random number.
+  The driver uses CPU RNG instructions to produce high-quality,
+  high-performance entropy and random number.

    RNG Algorithms defined in UEFI 2.4:
-   - EFI_RNG_ALGORITHM_SP800_90_CTR_256_GUID  - Supported
-     (RDRAND implements a hardware NIST SP800-90 AES-CTR-256 based DRBG)
-   - EFI_RNG_ALGORITHM_RAW                    - Supported
-     (Structuring RDRAND invocation can be guaranteed as high-quality entropy 
source)
-   - EFI_RNG_ALGORITHM_SP800_90_HMAC_256_GUID - Unsupported
-   - EFI_RNG_ALGORITHM_SP800_90_HASH_256_GUID - Unsupported
-   - EFI_RNG_ALGORITHM_X9_31_3DES_GUID        - Unsupported
-   - EFI_RNG_ALGORITHM_X9_31_AES_GUID         - Unsupported
+   - EFI_RNG_ALGORITHM_SP800_90_CTR_256_GUID
+   - EFI_RNG_ALGORITHM_RAW
+   - EFI_RNG_ALGORITHM_SP800_90_HMAC_256_GUID
+   - EFI_RNG_ALGORITHM_SP800_90_HASH_256_GUID
+   - EFI_RNG_ALGORITHM_X9_31_3DES_GUID
+   - EFI_RNG_ALGORITHM_X9_31_AES_GUID

  Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
  (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>
+
  SPDX-License-Identifier: BSD-2-Clause-Patent

  **/

-#include "RdRand.h"
+#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/RngLib.h>
+#include <Library/TimerLib.h>
+#include <Protocol/Rng.h>

-//
-// Supported RNG Algorithms list by this driver.
-//
-EFI_RNG_ALGORITHM mSupportedRngAlgorithms[] = {
-  EFI_RNG_ALGORITHM_SP800_90_CTR_256_GUID,
-  EFI_RNG_ALGORITHM_RAW
-};
+#include "RngDxeInternals.h"

  /**
    Returns information about the random number generation implementation.
@@ -62,106 +60,23 @@ RngGetInfo (
    )
  {
    EFI_STATUS    Status;
-  UINTN         RequiredSize;

    if ((This == NULL) || (RNGAlgorithmListSize == NULL)) {
      return EFI_INVALID_PARAMETER;
    }

-  RequiredSize = sizeof (mSupportedRngAlgorithms);
-  if (*RNGAlgorithmListSize < RequiredSize) {
-    Status = EFI_BUFFER_TOO_SMALL;
+  //
+  // Return algorithm list supported by driver.
+  //
+  if (RNGAlgorithmList != NULL) {
+    Status = ArchGetSupportedRngAlgorithms (RNGAlgorithmListSize, 
RNGAlgorithmList);
    } else {
-    //
-    // Return algorithm list supported by driver.
-    //
-    if (RNGAlgorithmList != NULL) {
-      CopyMem (RNGAlgorithmList, mSupportedRngAlgorithms, RequiredSize);
-      Status = EFI_SUCCESS;
-    } else {
-      Status = EFI_INVALID_PARAMETER;
-    }
+    Status = EFI_INVALID_PARAMETER;
    }
-  *RNGAlgorithmListSize = RequiredSize;

    return Status;
  }

-/**
-  Produces and returns an RNG value using either the default or specified RNG 
algorithm.
-
-  @param[in]  This                    A pointer to the EFI_RNG_PROTOCOL 
instance.
-  @param[in]  RNGAlgorithm            A pointer to the EFI_RNG_ALGORITHM that 
identifies the RNG
-                                      algorithm to use. May be NULL in which 
case the function will
-                                      use its default RNG algorithm.
-  @param[in]  RNGValueLength          The length in bytes of the memory buffer 
pointed to by
-                                      RNGValue. The driver shall return 
exactly this numbers of bytes.
-  @param[out] RNGValue                A caller-allocated memory buffer filled 
by the driver with the
-                                      resulting RNG value.
-
-  @retval EFI_SUCCESS                 The RNG value was returned successfully.
-  @retval EFI_UNSUPPORTED             The algorithm specified by RNGAlgorithm 
is not supported by
-                                      this driver.
-  @retval EFI_DEVICE_ERROR            An RNG value could not be retrieved due 
to a hardware or
-                                      firmware error.
-  @retval EFI_NOT_READY               There is not enough random data 
available to satisfy the length
-                                      requested by RNGValueLength.
-  @retval EFI_INVALID_PARAMETER       RNGValue is NULL or RNGValueLength is 
zero.
-
-**/
-EFI_STATUS
-EFIAPI
-RngGetRNG (
-  IN EFI_RNG_PROTOCOL            *This,
-  IN EFI_RNG_ALGORITHM           *RNGAlgorithm, OPTIONAL
-  IN UINTN                       RNGValueLength,
-  OUT UINT8                      *RNGValue
-  )
-{
-  EFI_STATUS    Status;
-
-  if ((RNGValueLength == 0) || (RNGValue == NULL)) {
-    return EFI_INVALID_PARAMETER;
-  }
-
-  Status = EFI_UNSUPPORTED;
-  if (RNGAlgorithm == NULL) {
-    //
-    // Use the default RNG algorithm if RNGAlgorithm is NULL.
-    //
-    RNGAlgorithm = &gEfiRngAlgorithmSp80090Ctr256Guid;
-  }
-
-  //
-  // NIST SP800-90-AES-CTR-256 supported by RDRAND
-  //
-  if (CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmSp80090Ctr256Guid)) {
-    Status = RdRandGetBytes (RNGValueLength, RNGValue);
-    return Status;
-  }
-
-  //
-  // The "raw" algorithm is intended to provide entropy directly
-  //
-  if (CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmRaw)) {
-    //
-    // When a DRBG is used on the output of a entropy source,
-    // its security level must be at least 256 bits according to UEFI Spec.
-    //
-    if (RNGValueLength < 32) {
-      return EFI_INVALID_PARAMETER;
-    }
-
-    Status = RdRandGenerateEntropy (RNGValueLength, RNGValue);
-    return Status;
-  }
-
-  //
-  // Other algorithms were unsupported by this driver.
-  //
-  return Status;
-}
-
  //
  // The Random Number Generator (RNG) protocol
  //
@@ -204,3 +119,44 @@ RngDriverEntry (

    return Status;
  }
+
+
+/**
+  Calls RDRAND 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.
+
+  @retval EFI_SUCCESS        Random bytes generation succeeded.
+  @retval EFI_NOT_READY      Failed to request random bytes.
+
+**/
+EFI_STATUS
+EFIAPI
+RngGetBytes (
+  IN UINTN         Length,
+  OUT UINT8        *RandBuffer
+  )
+{
+  BOOLEAN     IsRandom;
+  UINT64      TempRand[2];
+
+  while (Length > 0) {
+    IsRandom = GetRandomNumber128 (TempRand);
+    if (!IsRandom) {
+      return EFI_NOT_READY;
+    }
+    if (Length >= sizeof (TempRand)) {
+      WriteUnaligned64 ((UINT64*)RandBuffer, TempRand[0]);
+      RandBuffer += sizeof (UINT64);
+      WriteUnaligned64 ((UINT64*)RandBuffer, TempRand[1]);
+      RandBuffer += sizeof (UINT64);
+      Length -= sizeof (TempRand);
+    } else {
+      CopyMem (RandBuffer, TempRand, Length);
+      Length = 0;
+    }
+  }
+
+  return EFI_SUCCESS;
+}

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