OvmfPkg/Tcg2ConfigPei: skip TPM-1.2 detection when building for ARM/AARCH64

Dating back to commits f5cb3767038e and ddd34a818315d, the
"ArmVirtPkg/ArmVirtQemu.dsc" platform includes the
"OvmfPkg/Tcg/Tcg2Config/Tcg2ConfigPei.inf" module when the TPM2_ENABLE
build flag is defined.

This was regressed in commit 89236992913f, which added a Tpm12DeviceLib
dependency to Tcg2ConfigPei. "ArmVirtQemu.dsc" does not resolve that class
to any instance, so now we get a build failure:

> build.py...
> ArmVirtPkg/ArmVirtQemu.dsc(...): error 4000: Instance of library class
> [Tpm12DeviceLib] is not found
>         in [OvmfPkg/Tcg/Tcg2Config/Tcg2ConfigPei.inf] [AARCH64]
>         consumed by module [OvmfPkg/Tcg/Tcg2Config/Tcg2ConfigPei.inf]

The TPM-1.2 code in OvmfPkg/Tcg2ConfigPei is limited to a special use case
(a kind of physical TPM-1.2 assignment), and that has never applied to
"ArmVirtQemu.dsc".

Short-circuit the TPM-1.2 detection in the ARM/AARCH64 builds of
OvmfPkg/Tcg2ConfigPei, removing the Tpm12DeviceLib dependency.

Functionally, this patch is a no-op on IA32 / X64.

Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Cc: Simon Hardy <simon.hardy@itdev.co.uk>
Cc: Stefan Berger <stefanb@linux.ibm.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2728
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20200520225841.17793-4-lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@arm.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/OvmfPkg/Tcg/Tcg2Config/Tpm12SupportNull.c b/OvmfPkg/Tcg/Tcg2Config/Tpm12SupportNull.c
new file mode 100644
index 0000000000..7bb377b9b9
--- /dev/null
+++ b/OvmfPkg/Tcg/Tcg2Config/Tpm12SupportNull.c
@@ -0,0 +1,25 @@
+/** @file

+  Null implementation of InternalTpm12Detect(), always returning

+  EFI_UNSUPPORTED.

+

+  Copyright (C) 2020, Red Hat, Inc.

+

+  SPDX-License-Identifier: BSD-2-Clause-Patent

+**/

+

+#include "Tpm12Support.h"

+

+/**

+  Detect the presence of a TPM with interface version 1.2.

+

+  @retval EFI_UNSUPPORTED  The platform that includes this particular

+                           implementation of the function does not support

+                           TPM-1.2.

+**/

+EFI_STATUS

+InternalTpm12Detect (

+  VOID

+  )

+{

+  return EFI_UNSUPPORTED;

+}