From ee4dd84fe0d33568b1800f5d6840627103c46d8d Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Wed, 24 Jun 2020 11:40:09 +0200
Subject: [PATCH 19/21] SecurityPkg/Tcg2Dxe: suppress error on no swtpm in
 silent aa64 build (RH)

Notes about the RHEL-8.3/20200603-ca407c7246bf [edk2-stable202005] ->
RHEL-8.5/20210520-e1999b264f1f [edk2-stable202105] rebase:

- Remove obsolete commit message tags related to downstream patch
  management: Message-id, Patchwork-id, O-Subject, Acked-by, From,
  RH-Acked-by, RH-Author (RHBZ#1846481).

Bugzilla: 1844682

If swtpm / vTPM2 is not being used, Tcg2Dxe should return EFI_UNSUPPORTED,
so that the DXE Core can unload it. However, the associated error message,
logged by the DXE Core to the serial console, is not desired in the silent
edk2-aarch64 build, given that the absence of swtpm / vTPM2 is nothing out
of the ordinary. Therefore, return success and stay resident. The wasted
guest RAM still gets freed after ExitBootServices().

(Inspired by RHEL-8.1.0 commit aaaedc1e2cfd.)

Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
(cherry picked from commit cbce29f7749477e271f9764fed82de94724af5df)
---
 SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.inf |  1 +
 SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c   | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.inf b/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.inf
index 7dc7a2683d71..3bc88339311e 100644
--- a/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.inf
+++ b/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.inf
@@ -55,6 +55,7 @@ [LibraryClasses]
   UefiRuntimeServicesTableLib
   BaseMemoryLib
   DebugLib
+  DebugPrintErrorLevelLib
   Tpm2CommandLib
   PrintLib
   UefiLib
diff --git a/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c b/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c
index f6ea8b2bbf18..681eb7e08b98 100644
--- a/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c
+++ b/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c
@@ -28,6 +28,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include <Protocol/ResetNotification.h>
 
 #include <Library/DebugLib.h>
+#include <Library/DebugPrintErrorLevelLib.h>
 #include <Library/BaseMemoryLib.h>
 #include <Library/UefiRuntimeServicesTableLib.h>
 #include <Library/UefiDriverEntryPoint.h>
@@ -2691,6 +2692,22 @@ DriverEntry (
       CompareGuid (PcdGetPtr (PcdTpmInstanceGuid), &gEfiTpmDeviceInstanceTpm12Guid))
   {
     DEBUG ((DEBUG_INFO, "No TPM2 instance required!\n"));
+#if defined (MDE_CPU_AARCH64)
+    //
+    // RHBZ#1844682
+    //
+    // If swtpm / vTPM2 is not being used, this driver should return
+    // EFI_UNSUPPORTED, so that the DXE Core can unload it. However, the
+    // associated error message, logged by the DXE Core to the serial console,
+    // is not desired in the silent edk2-aarch64 build, given that the absence
+    // of swtpm / vTPM2 is nothing out of the ordinary. Therefore, return
+    // success and stay resident. The wasted guest RAM still gets freed after
+    // ExitBootServices().
+    //
+    if (GetDebugPrintErrorLevel () == DEBUG_ERROR) {
+      return EFI_SUCCESS;
+    }
+#endif
     return EFI_UNSUPPORTED;
   }
 
-- 
2.35.3