From 5bdf8acc138474408a7f39e793e5dfe571d0421b Mon Sep 17 00:00:00 2001
From: Sami Mujawar <sami.mujawar@arm.com>
Date: Fri, 8 Jul 2022 17:07:00 +0100
Subject: [PATCH] MdePkg: Add helper function to detect RME

Add helper function to check if the Realm Management
Extension (RME) is implemented by the hardware.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Leif Lindholm <leif.lindholm@oss.qualcomm.com>
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
---
 MdePkg/Include/AArch64/AArch64.h           |  1 +
 MdePkg/Include/Library/ArmLib.h            | 13 ++++++++++++-
 MdePkg/Library/ArmLib/AArch64/AArch64Lib.c | 16 +++++++++++++++-
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/MdePkg/Include/AArch64/AArch64.h b/MdePkg/Include/AArch64/AArch64.h
index 40ecd7b668..7349dcf077 100644
--- a/MdePkg/Include/AArch64/AArch64.h
+++ b/MdePkg/Include/AArch64/AArch64.h
@@ -36,6 +36,7 @@
 // ID_AA64PFR0 - AArch64 Processor Feature Register 0 definitions
 #define AARCH64_PFR0_FP   (0xF << 16)
 #define AARCH64_PFR0_GIC  (0xF << 24)
+#define AARCH64_PFR0_RME  (0xFULL << 52)
 
 // ID_AA64PFR2 - AArch64 Processor Feature Register 2 definitions
 #define AARCH64_PFR2_GCIE  (0xF << 12)
diff --git a/MdePkg/Include/Library/ArmLib.h b/MdePkg/Include/Library/ArmLib.h
index 2a830b6ba7..3f38c026e4 100644
--- a/MdePkg/Include/Library/ArmLib.h
+++ b/MdePkg/Include/Library/ArmLib.h
@@ -1,7 +1,7 @@
 /** @file
 
   Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
-  Copyright (c) 2011 - 2016, ARM Ltd. All rights reserved.<BR>
+  Copyright (c) 2011 - 2023, Arm Limited. All rights reserved.<BR>
   Copyright (c) 2020 - 2021, NUVIA Inc. All rights reserved.<BR>
 
   SPDX-License-Identifier: BSD-2-Clause-Patent
@@ -721,3 +721,14 @@ EFIAPI
 ArmHas52BitTgran4 (
   VOID
   );
+
+/** Checks if RME is implemented.
+
+   @retval TRUE  RME is implemented.
+   @retval FALSE RME is not implemented.
+**/
+BOOLEAN
+EFIAPI
+ArmHasRme (
+  VOID
+  );
diff --git a/MdePkg/Library/ArmLib/AArch64/AArch64Lib.c b/MdePkg/Library/ArmLib/AArch64/AArch64Lib.c
index 53ea3966a1..ead6dc813a 100644
--- a/MdePkg/Library/ArmLib/AArch64/AArch64Lib.c
+++ b/MdePkg/Library/ArmLib/AArch64/AArch64Lib.c
@@ -1,7 +1,7 @@
 /** @file
 
   Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
-  Portions copyright (c) 2011 - 2014, ARM Ltd. All rights reserved.<BR>
+  Portions copyright (c) 2011 - 2023, Arm Limited. All rights reserved.<BR>
   Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
 
   SPDX-License-Identifier: BSD-2-Clause-Patent
@@ -127,3 +127,17 @@ ArmHas52BitTgran4 (
 
   return ((Mmfr0 & AARCH64_MMFR0_TGRAN4_MASK) == AARCH64_MMFR0_TGRAN4_52BITS);
 }
+
+/** Checks if RME is implemented.
+
+   @retval TRUE  RME is implemented.
+   @retval FALSE RME is not implemented.
+**/
+BOOLEAN
+EFIAPI
+ArmHasRme (
+  VOID
+  )
+{
+  return ((ArmReadIdAA64Pfr0 () & AARCH64_PFR0_RME) != 0);
+}