[PATCH 2/3] MdePkg: Refactor BaseRngLib to support AARCH64 in addition to X86

["Rebecca Cran" <rebecca@nuviainc.com>]

Make BaseRngLib more generic by moving x86 specific functionality from
BaseRng.c into Rand/RdRand.c, and adding AArch64/Rndr.c, which supports
the optional ARMv8.5 RNG instructions RNDR and RNDRRS that are a part of
FEAT_RNG.

Signed-off-by: Rebecca Cran <rebecca@nuviainc.com>
---
 MdePkg/MdePkg.dec                               |   9 +-
 MdePkg/MdePkg.dsc                               |   4 +-
 MdePkg/Library/BaseRngLib/BaseRngLib.inf        |  16 ++-
 MdePkg/Library/BaseRngLib/BaseRngLibInternals.h |  31 +++++
 MdePkg/Library/BaseRngLib/AArch64/Rndr.c        | 121 ++++++++++++++++++++
 MdePkg/Library/BaseRngLib/BaseRng.c             |  55 +++------
 MdePkg/Library/BaseRngLib/Rand/RdRand.c         | 103 +++++++++++++++++
 MdePkg/Library/BaseRngLib/BaseRngLib.uni        |   6 +-
 8 files changed, 291 insertions(+), 54 deletions(-)

diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
index 8965e903e093..b49f88d8e18f 100644
--- a/MdePkg/MdePkg.dec
+++ b/MdePkg/MdePkg.dec
@@ -267,6 +267,11 @@ [LibraryClasses]
   #
   RegisterFilterLib|Include/Library/RegisterFilterLib.h
 
+[LibraryClasses.IA32, LibraryClasses.X64, LibraryClasses.AARCH64]
+  ##  @libraryclass  Provides services to generate random number.
+  #
+  RngLib|Include/Library/RngLib.h
+
 [LibraryClasses.IA32, LibraryClasses.X64]
   ##  @libraryclass  Abstracts both S/W SMI generation and detection.
   ##
@@ -288,10 +293,6 @@ [LibraryClasses.IA32, LibraryClasses.X64]
   #
   SmmPeriodicSmiLib|Include/Library/SmmPeriodicSmiLib.h
 
-  ##  @libraryclass  Provides services to generate random number.
-  #
-  RngLib|Include/Library/RngLib.h
-
   ##  @libraryclass  Provides services to log the SMI handler registration.
   SmiHandlerProfileLib|Include/Library/SmiHandlerProfileLib.h
 
diff --git a/MdePkg/MdePkg.dsc b/MdePkg/MdePkg.dsc
index d363419006ea..a94959169b2f 100644
--- a/MdePkg/MdePkg.dsc
+++ b/MdePkg/MdePkg.dsc
@@ -145,6 +145,9 @@ [Components.IA32, Components.X64, Components.ARM, Components.AARCH64]
   MdePkg/Test/UnitTest/Library/BaseSafeIntLib/TestBaseSafeIntLibSmm.inf
   MdePkg/Test/UnitTest/Library/BaseSafeIntLib/TestBaseSafeIntLibUefiShell.inf
 
+[Components.IA32, Components.X64, Components.AARCH64]
+  MdePkg/Library/BaseRngLib/BaseRngLib.inf
+
 [Components.IA32, Components.X64]
   MdePkg/Library/BaseIoLibIntrinsic/BaseIoLibIntrinsic.inf
   MdePkg/Library/BaseIoLibIntrinsic/BaseIoLibIntrinsicSev.inf
@@ -168,7 +171,6 @@ [Components.IA32, Components.X64]
   MdePkg/Library/BaseS3StallLib/BaseS3StallLib.inf
   MdePkg/Library/SmmMemLib/SmmMemLib.inf
   MdePkg/Library/SmmIoLib/SmmIoLib.inf
-  MdePkg/Library/BaseRngLib/BaseRngLib.inf
   MdePkg/Library/SmmPciExpressLib/SmmPciExpressLib.inf
   MdePkg/Library/SmiHandlerProfileLibNull/SmiHandlerProfileLibNull.inf
   MdePkg/Library/MmServicesTableLib/MmServicesTableLib.inf
diff --git a/MdePkg/Library/BaseRngLib/BaseRngLib.inf b/MdePkg/Library/BaseRngLib/BaseRngLib.inf
index 31740751c69c..1dc3249a8c20 100644
--- a/MdePkg/Library/BaseRngLib/BaseRngLib.inf
+++ b/MdePkg/Library/BaseRngLib/BaseRngLib.inf
@@ -1,9 +1,10 @@
 ## @file
 #  Instance of RNG (Random Number Generator) Library.
 #
-#  BaseRng Library that uses CPU RdRand instruction access to provide
-#  high-quality random numbers.
+#  BaseRng Library that uses CPU RNG instructions (e.g. RdRand) to
+#  provide high-quality random numbers.
 #
+#  Copyright (c) 2020, NUVIA Inc. All rights reserved.<BR>
 #  Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
 #
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
@@ -22,11 +23,18 @@ [Defines]
   CONSTRUCTOR                    = BaseRngLibConstructor
 
 #
-#  VALID_ARCHITECTURES           = IA32 X64
+#  VALID_ARCHITECTURES           = IA32 X64 AARCH64
 #
 
-[Sources.Ia32, Sources.X64]
+[Sources]
   BaseRng.c
+  BaseRngLibInternals.h
+
+[Sources.Ia32, Sources.X64]
+  Rand/RdRand.c
+
+[Sources.AARCH64]
+  AArch64/Rndr.c
 
 [Packages]
   MdePkg/MdePkg.dec
diff --git a/MdePkg/Library/BaseRngLib/BaseRngLibInternals.h b/MdePkg/Library/BaseRngLib/BaseRngLibInternals.h
new file mode 100644
index 000000000000..44fda69c9eec
--- /dev/null
+++ b/MdePkg/Library/BaseRngLib/BaseRngLibInternals.h
@@ -0,0 +1,31 @@
+/** @file
+
+  Architecture specific interface to RNG functionality.
+
+Copyright (c) 2020, NUVIA Inc. All rights reserved.<BR>
+
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef BASE_RNGLIB_INTERNALS_H_
+
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber16 (
+  OUT UINT16 *Rand
+  );
+
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber32 (
+  OUT UINT32 *Rand
+  );
+
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber64 (
+  OUT UINT64 *Rand
+  );
+
+#endif    // BASE_RNGLIB_INTERNALS_H_
diff --git a/MdePkg/Library/BaseRngLib/AArch64/Rndr.c b/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
new file mode 100644
index 000000000000..19643237923a
--- /dev/null
+++ b/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
@@ -0,0 +1,121 @@
+/** @file
+  Random number generator service that uses the RNDR instruction
+  to provide high-quality random numbers.
+
+  Copyright (c) 2020, NUVIA Inc. All rights reserved.<BR>
+  Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+
+#include <Library/RngLib.h>
+
+#include "BaseRngLibInternals.h"
+
+//
+// Bit mask used to determine if RNDR instruction is supported.
+//
+#define RNDR_MASK                  ((UINT64)MAX_UINT16 << 60U)
+
+/**
+  The constructor function checks whether or not RNDR instruction is supported
+  by the host hardware.
+
+  The constructor function checks whether or not RNDR instruction is supported.
+  It will ASSERT() if RNDR instruction is not supported.
+  It will always return RETURN_SUCCESS.
+
+  @retval RETURN_SUCCESS   The constructor always returns EFI_SUCCESS.
+
+**/
+RETURN_STATUS
+EFIAPI
+BaseRngLibConstructor (
+  VOID
+  )
+{
+  UINT64 Isar0;
+  //
+  // Determine RNDR support by examining bits 63:60 of the ISAR0 register returned by
+  // MSR. A non-zero value indicates that the processor supports the RNDR instruction.
+  //
+  Isar0 = ArmReadIdIsar0 ();
+  ASSERT ((Isar0 & RNDR_MASK) != 0);
+  (void)Isar0;
+
+  return RETURN_SUCCESS;
+}
+
+
+/**
+  Generates a 16-bit random number.
+
+  @param[out] Rand     Buffer pointer to store the 16-bit random value.
+
+  @retval TRUE         Random number generated successfully.
+  @retval FALSE        Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber16 (
+  OUT     UINT16                    *Rand
+  )
+{
+  UINT64 Rand64;
+
+  if (ArchGetRandomNumber64 (&Rand64)) {
+    *Rand = Rand64 & MAX_UINT16;
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
+/**
+  Generates a 32-bit random number.
+
+  @param[out] Rand     Buffer pointer to store the 32-bit random value.
+
+  @retval TRUE         Random number generated successfully.
+  @retval FALSE        Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber32 (
+  OUT     UINT32                    *Rand
+  )
+{
+  UINT64 Rand64;
+
+  if (ArchGetRandomNumber64 (&Rand64)) {
+    *Rand = Rand64 & MAX_UINT32;
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
+/**
+  Generates a 64-bit random number.
+
+  @param[out] Rand     Buffer pointer to store the 64-bit random value.
+
+  @retval TRUE         Random number generated successfully.
+  @retval FALSE        Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber64 (
+  OUT     UINT64                    *Rand
+  )
+{
+  return ArmRndr (Rand);
+}
+
diff --git a/MdePkg/Library/BaseRngLib/BaseRng.c b/MdePkg/Library/BaseRngLib/BaseRng.c
index 7ad7aec9d38f..072fa37d3394 100644
--- a/MdePkg/Library/BaseRngLib/BaseRng.c
+++ b/MdePkg/Library/BaseRngLib/BaseRng.c
@@ -1,8 +1,10 @@
 /** @file
-  Random number generator services that uses RdRand instruction access
-  to provide high-quality random numbers.
+  Random number generator services that uses CPU RNG instructions to
+  provide high-quality random numbers.
 
+Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
 Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
+
 SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -10,46 +12,15 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include <Library/BaseLib.h>
 #include <Library/DebugLib.h>
 
-//
-// Bit mask used to determine if RdRand instruction is supported.
-//
-#define RDRAND_MASK                  BIT30
+#include "BaseRngLibInternals.h"
 
 //
 // Limited retry number when valid random data is returned.
 // Uses the recommended value defined in Section 7.3.17 of "Intel 64 and IA-32
-// Architectures Software Developer's Mannual".
+// Architectures Software Developer's Manual".
 //
-#define RDRAND_RETRY_LIMIT           10
+#define GETRANDOM_RETRY_LIMIT           10
 
-/**
-  The constructor function checks whether or not RDRAND instruction is supported
-  by the host hardware.
-
-  The constructor function checks whether or not RDRAND instruction is supported.
-  It will ASSERT() if RDRAND instruction is not supported.
-  It will always return RETURN_SUCCESS.
-
-  @retval RETURN_SUCCESS   The constructor always returns EFI_SUCCESS.
-
-**/
-RETURN_STATUS
-EFIAPI
-BaseRngLibConstructor (
-  VOID
-  )
-{
-  UINT32  RegEcx;
-
-  //
-  // Determine RDRAND support by examining bit 30 of the ECX register returned by
-  // CPUID. A value of 1 indicates that processor support RDRAND instruction.
-  //
-  AsmCpuid (1, 0, 0, &RegEcx, 0);
-  ASSERT ((RegEcx & RDRAND_MASK) == RDRAND_MASK);
-
-  return RETURN_SUCCESS;
-}
 
 /**
   Generates a 16-bit random number.
@@ -75,8 +46,8 @@ GetRandomNumber16 (
   //
   // A loop to fetch a 16 bit random value with a retry count limit.
   //
-  for (Index = 0; Index < RDRAND_RETRY_LIMIT; Index++) {
-    if (AsmRdRand16 (Rand)) {
+  for (Index = 0; Index < GETRANDOM_RETRY_LIMIT; Index++) {
+    if (ArchGetRandomNumber16 (Rand)) {
       return TRUE;
     }
   }
@@ -108,8 +79,8 @@ GetRandomNumber32 (
   //
   // A loop to fetch a 32 bit random value with a retry count limit.
   //
-  for (Index = 0; Index < RDRAND_RETRY_LIMIT; Index++) {
-    if (AsmRdRand32 (Rand)) {
+  for (Index = 0; Index < GETRANDOM_RETRY_LIMIT; Index++) {
+    if (ArchGetRandomNumber32 (Rand)) {
       return TRUE;
     }
   }
@@ -141,8 +112,8 @@ GetRandomNumber64 (
   //
   // A loop to fetch a 64 bit random value with a retry count limit.
   //
-  for (Index = 0; Index < RDRAND_RETRY_LIMIT; Index++) {
-    if (AsmRdRand64 (Rand)) {
+  for (Index = 0; Index < GETRANDOM_RETRY_LIMIT; Index++) {
+    if (ArchGetRandomNumber64 (Rand)) {
       return TRUE;
     }
   }
diff --git a/MdePkg/Library/BaseRngLib/Rand/RdRand.c b/MdePkg/Library/BaseRngLib/Rand/RdRand.c
new file mode 100644
index 000000000000..3f1378064b4c
--- /dev/null
+++ b/MdePkg/Library/BaseRngLib/Rand/RdRand.c
@@ -0,0 +1,103 @@
+/** @file
+  Random number generator services that uses RdRand instruction access
+  to provide high-quality random numbers.
+
+Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
+
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+
+#include "BaseRngLibInternals.h"
+
+//
+// Bit mask used to determine if RdRand instruction is supported.
+//
+#define RDRAND_MASK                  BIT30
+
+/**
+  The constructor function checks whether or not RDRAND instruction is supported
+  by the host hardware.
+
+  The constructor function checks whether or not RDRAND instruction is supported.
+  It will ASSERT() if RDRAND instruction is not supported.
+  It will always return RETURN_SUCCESS.
+
+  @retval RETURN_SUCCESS   The constructor always returns EFI_SUCCESS.
+
+**/
+RETURN_STATUS
+EFIAPI
+BaseRngLibConstructor (
+  VOID
+  )
+{
+  UINT32  RegEcx;
+
+  //
+  // Determine RDRAND support by examining bit 30 of the ECX register returned by
+  // CPUID. A value of 1 indicates that processor support RDRAND instruction.
+  //
+  AsmCpuid (1, 0, 0, &RegEcx, 0);
+  ASSERT ((RegEcx & RDRAND_MASK) == RDRAND_MASK);
+
+  return RETURN_SUCCESS;
+}
+
+/**
+  Generates a 16-bit random number.
+
+  @param[out] Rand     Buffer pointer to store the 16-bit random value.
+
+  @retval TRUE         Random number generated successfully.
+  @retval FALSE        Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber16 (
+  OUT     UINT16                    *Rand
+  )
+{
+  return AsmRdRand16 (Rand);
+}
+
+/**
+  Generates a 32-bit random number.
+
+  @param[out] Rand     Buffer pointer to store the 32-bit random value.
+
+  @retval TRUE         Random number generated successfully.
+  @retval FALSE        Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber32 (
+  OUT     UINT32                    *Rand
+  )
+{
+  return AsmRdRand32 (Rand);
+}
+
+/**
+  Generates a 64-bit random number.
+
+  @param[out] Rand     Buffer pointer to store the 64-bit random value.
+
+  @retval TRUE         Random number generated successfully.
+  @retval FALSE        Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+ArchGetRandomNumber64 (
+  OUT     UINT64                    *Rand
+  )
+{
+  return AsmRdRand64 (Rand);
+}
+
diff --git a/MdePkg/Library/BaseRngLib/BaseRngLib.uni b/MdePkg/Library/BaseRngLib/BaseRngLib.uni
index f3ed954c5209..8c7fe1219450 100644
--- a/MdePkg/Library/BaseRngLib/BaseRngLib.uni
+++ b/MdePkg/Library/BaseRngLib/BaseRngLib.uni
@@ -1,8 +1,8 @@
 // /** @file
 // Instance of RNG (Random Number Generator) Library.
 //
-// BaseRng Library that uses CPU RdRand instruction access to provide
-// high-quality random numbers.
+// BaseRng Library that uses CPU RNG instructions to provide high-quality
+// random numbers.
 //
 // Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
 //
@@ -13,5 +13,5 @@
 
 #string STR_MODULE_ABSTRACT             #language en-US "Instance of RNG Library"
 
-#string STR_MODULE_DESCRIPTION          #language en-US "BaseRng Library that uses CPU RdRand instruction access to provide high-quality random numbers"
+#string STR_MODULE_DESCRIPTION          #language en-US "BaseRng Library that uses CPU RNG instructions to provide high-quality random numbers"
 
-- 
2.26.2