[PATCH v3 1/2] MdePkg/BaseRngLib: Add support for ARMv8.5 RNG instructions


Rebecca Cran
 

Make BaseRngLib more generic by moving x86-specific functionality into
'Rand' and adding files under 'AArch64' to support the optional ARMv8.5
RNG instruction RNDR that is 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 | 23 +++-
MdePkg/Library/BaseRngLib/AArch64/ArmRng.h | 43 ++++++
MdePkg/Library/BaseRngLib/BaseRngLibInternals.h | 78 +++++++++++
MdePkg/Library/BaseRngLib/AArch64/Rndr.c | 139 ++++++++++++++++++++
MdePkg/Library/BaseRngLib/BaseRng.c | 87 ++++++------
MdePkg/Library/BaseRngLib/Rand/RdRand.c | 131 ++++++++++++++++++
MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.S | 31 +++++
MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.asm | 30 +++++
MdePkg/Library/BaseRngLib/AArch64/ArmRng.S | 37 ++++++
MdePkg/Library/BaseRngLib/AArch64/ArmRng.asm | 39 ++++++
MdePkg/Library/BaseRngLib/BaseRngLib.uni | 6 +-
13 files changed, 603 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..1fcceb941495 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 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
@@ -22,11 +23,25 @@ [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
+ AArch64/ArmRng.h
+
+ AArch64/ArmReadIdIsar0.S | GCC
+ AArch64/ArmRng.S | GCC
+
+ AArch64/ArmReadIdIsar0.asm | MSFT
+ AArch64/ArmRng.asm | MSFT

[Packages]
MdePkg/MdePkg.dec
diff --git a/MdePkg/Library/BaseRngLib/AArch64/ArmRng.h b/MdePkg/Library/BaseRngLib/AArch64/ArmRng.h
new file mode 100644
index 000000000000..a597e98bf0d5
--- /dev/null
+++ b/MdePkg/Library/BaseRngLib/AArch64/ArmRng.h
@@ -0,0 +1,43 @@
+/** @file
+ Random number generator service that uses the RNDR instruction
+ to provide pseudorandom numbers.
+
+ Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef ARM_RNG_H_
+#define ARM_RNG_H_
+
+/**
+ Generates a random number using RNDR.
+ Returns TRUE on success; FALSE on failure.
+
+ @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
+ArmRndr (
+ OUT UINT64 *Rand
+ );
+
+/**
+ Reads the ID_AA64ISAR0 Register.
+
+ @return The contents of the ID_AA64ISAR0 register.
+
+**/
+UINT64
+EFIAPI
+ArmReadIdIsar0 (
+ VOID
+ );
+
+#endif /* ARM_RNG_H_ */
+
diff --git a/MdePkg/Library/BaseRngLib/BaseRngLibInternals.h b/MdePkg/Library/BaseRngLib/BaseRngLibInternals.h
new file mode 100644
index 000000000000..b6b4e9eef227
--- /dev/null
+++ b/MdePkg/Library/BaseRngLib/BaseRngLibInternals.h
@@ -0,0 +1,78 @@
+/** @file
+
+ Architecture specific interface to RNG functionality.
+
+Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
+
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef BASE_RNGLIB_INTERNALS_H_
+
+/**
+ 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
+ );
+
+/**
+ 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
+ );
+
+/**
+ 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
+ );
+
+/**
+ Checks whether the RNG instruction is supported.
+
+ @retval TRUE RNG instruction is supported.
+ @retval FALSE RNG instruction is not supported.
+
+**/
+BOOLEAN
+EFIAPI
+ArchIsRngSupported (
+ VOID
+ );
+
+#if defined (MDE_CPU_AARCH64)
+
+// RNDR, Random Number
+#define RNDR S3_3_C2_C4_0
+
+#endif
+
+#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..c9f8c813ed35
--- /dev/null
+++ b/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
@@ -0,0 +1,139 @@
+/** @file
+ Random number generator service that uses the RNDR instruction
+ to provide pseudorandom 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
+
+**/
+
+#include <Uefi.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/RngLib.h>
+
+#include "ArmRng.h"
+#include "BaseRngLibInternals.h"
+
+STATIC BOOLEAN mRndrSupported;
+
+//
+// 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 EFI_SUCCESS.
+
+ @retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.
+
+**/
+EFI_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);
+
+ mRndrSupported = ((Isar0 & RNDR_MASK) != 0);
+
+ return EFI_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);
+}
+
+/**
+ Checks whether RNDR is supported.
+
+ @retval TRUE RNDR is supported.
+ @retval FALSE RNDR is not supported.
+
+**/
+BOOLEAN
+EFIAPI
+ArchIsRngSupported (
+ VOID
+ )
+{
+ return mRndrSupported;
+}
diff --git a/MdePkg/Library/BaseRngLib/BaseRng.c b/MdePkg/Library/BaseRngLib/BaseRng.c
index 7ad7aec9d38f..5b63d8f7146b 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 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.
@@ -72,11 +43,19 @@ GetRandomNumber16 (

ASSERT (Rand != NULL);

+ if (Rand == NULL) {
+ return FALSE;
+ }
+
+ if (!ArchIsRngSupported ()) {
+ return FALSE;
+ }
+
//
// 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;
}
}
@@ -105,11 +84,19 @@ GetRandomNumber32 (

ASSERT (Rand != NULL);

+ if (Rand == NULL) {
+ return FALSE;
+ }
+
+ if (!ArchIsRngSupported ()) {
+ return FALSE;
+ }
+
//
// 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;
}
}
@@ -138,11 +125,19 @@ GetRandomNumber64 (

ASSERT (Rand != NULL);

+ if (Rand == NULL) {
+ return FALSE;
+ }
+
+ if (!ArchIsRngSupported ()) {
+ return FALSE;
+ }
+
//
// 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;
}
}
@@ -169,6 +164,14 @@ GetRandomNumber128 (
{
ASSERT (Rand != NULL);

+ if (Rand == NULL) {
+ return FALSE;
+ }
+
+ if (!ArchIsRngSupported ()) {
+ return FALSE;
+ }
+
//
// Read first 64 bits
//
diff --git a/MdePkg/Library/BaseRngLib/Rand/RdRand.c b/MdePkg/Library/BaseRngLib/Rand/RdRand.c
new file mode 100644
index 000000000000..09fb875ac3f9
--- /dev/null
+++ b/MdePkg/Library/BaseRngLib/Rand/RdRand.c
@@ -0,0 +1,131 @@
+/** @file
+ Random number generator services that uses RdRand instruction access
+ 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
+
+**/
+
+#include <Uefi.h>
+#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
+
+
+STATIC BOOLEAN mRdRandSupported;
+
+/**
+ 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 EFI_SUCCESS.
+
+ @retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.
+
+**/
+EFI_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);
+
+ mRdRandSupported = ((RegEcx & RDRAND_MASK) == RDRAND_MASK);
+
+ return EFI_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);
+}
+
+/**
+ Checks whether RDRAND is supported.
+
+ @retval TRUE RDRAND is supported.
+ @retval FALSE RDRAND is not supported.
+
+**/
+BOOLEAN
+EFIAPI
+ArchIsRngSupported (
+ VOID
+ )
+{
+ /*
+ Existing software depends on this always returning TRUE, so for
+ now hard-code it.
+
+ return mRdRandSupported;
+ */
+ return TRUE;
+}
diff --git a/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.S b/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.S
new file mode 100644
index 000000000000..82a00d362212
--- /dev/null
+++ b/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.S
@@ -0,0 +1,31 @@
+#------------------------------------------------------------------------------
+#
+# ArmReadIdIsar0() for AArch64
+#
+# Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
+#
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#------------------------------------------------------------------------------
+
+.text
+.p2align 2
+GCC_ASM_EXPORT(ArmReadIdIsar0)
+
+#/**
+# Reads the ID_AA64ISAR0 Register.
+#
+# @return The contents of the ID_AA64ISAR0 register.
+#
+#**/
+#UINT64
+#EFIAPI
+#ArmReadIdIsar0 (
+# VOID
+# );
+#
+ASM_PFX(ArmReadIdIsar0):
+ mrs x0, id_aa64isar0_el1 // Read ID_AA64ISAR0 Register
+ ret
+
+
diff --git a/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.asm b/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.asm
new file mode 100644
index 000000000000..1d9f9a808c0c
--- /dev/null
+++ b/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.asm
@@ -0,0 +1,30 @@
+;------------------------------------------------------------------------------
+;
+; ArmReadIdIsar0() for AArch64
+;
+; Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
+;
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+;------------------------------------------------------------------------------
+
+ EXPORT ArmReadIdIsar0
+ AREA BaseLib_LowLevel, CODE, READONLY
+
+;/**
+; Reads the ID_AA64ISAR0 Register.
+;
+; @return The contents of the ID_AA64ISAR0 register.
+;
+;**/
+;UINT64
+;EFIAPI
+;ArmReadIdIsar0 (
+; VOID
+; );
+;
+ArmReadIdIsar0
+ mrs x0, id_aa64isar0_el1 // Read ID_AA64ISAR0 Register
+ ret
+
+ END
diff --git a/MdePkg/Library/BaseRngLib/AArch64/ArmRng.S b/MdePkg/Library/BaseRngLib/AArch64/ArmRng.S
new file mode 100644
index 000000000000..5159f467e3a6
--- /dev/null
+++ b/MdePkg/Library/BaseRngLib/AArch64/ArmRng.S
@@ -0,0 +1,37 @@
+#------------------------------------------------------------------------------
+#
+# ArmRndr() for AArch64
+#
+# Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
+#
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#------------------------------------------------------------------------------
+
+#include "BaseRngLibInternals.h"
+
+.text
+.p2align 2
+GCC_ASM_EXPORT(ArmRndr)
+
+#/**
+# Generates a random number using RNDR.
+# Returns TRUE on success; FALSE on failure.
+#
+# @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
+#ArmRndr (
+# OUT UINT64 *Rand
+# );
+#
+ASM_PFX(ArmRndr):
+ mrs x1, RNDR
+ str x1, [x0]
+ cset x0, ne // RNDR sets NZCV to 0b0100 on failure
+ ret
diff --git a/MdePkg/Library/BaseRngLib/AArch64/ArmRng.asm b/MdePkg/Library/BaseRngLib/AArch64/ArmRng.asm
new file mode 100644
index 000000000000..33144196cb54
--- /dev/null
+++ b/MdePkg/Library/BaseRngLib/AArch64/ArmRng.asm
@@ -0,0 +1,39 @@
+;------------------------------------------------------------------------------
+;
+; ArmRndr() for AArch64
+;
+; Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
+;
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+;------------------------------------------------------------------------------
+
+#include "BaseRngLibInternals.h"
+
+ EXPORT ArmRndr
+ AREA BaseLib_LowLevel, CODE, READONLY
+
+
+;/**
+; Generates a random number using RNDR.
+; Returns TRUE on success; FALSE on failure.
+;
+; @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
+;ArmRndr (
+; OUT UINT64 *Rand
+; );
+;
+ArmRndr
+ mrs x1, RNDR
+ str x1, [x0]
+ cset x0, ne // RNDR sets NZCV to 0b0100 on failure
+ ret
+
+ END
diff --git a/MdePkg/Library/BaseRngLib/BaseRngLib.uni b/MdePkg/Library/BaseRngLib/BaseRngLib.uni
index f3ed954c5209..de5d4f9dd869 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
+// 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 random numbers"

--
2.26.2

Join devel@edk2.groups.io to automatically receive all group messages.