[PATCH v1 35/41] PrmPkg: Replace PcdPrmPlatformGuid with EDKII_DSC_PLATFORM_GUID

["Michael Kubacki" <mikuback@linux.microsoft.com>]

From: Michael Kubacki <michael.kubacki@microsoft.com>

Bugzilla request https://bugzilla.tianocore.org/show_bug.cgi?id=2969
was recently completed which causes the PLATFORM_GUID value from the
DSC file to be placed into Autogen file .c & .h files. With this
change, the PRM Platform GUID can be directly matched to the DSC
PLATFORM_GUID value.

Cc: Andrew Fish <afish@apple.com>
Cc: Kang Gao <kang.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Benjamin You <benjamin.you@intel.com>
Cc: Liu Yun <yun.y.liu@intel.com>
Cc: Ankit Sinha <ankit.sinha@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
---
 PrmPkg/PrmLoaderDxe/PrmLoaderDxe.c   | 12 +++++-----
 PrmPkg/Include/PrmExportDescriptor.h |  2 ++
 PrmPkg/PrmLoaderDxe/PrmLoaderDxe.inf |  1 -
 PrmPkg/PrmPkg.dec                    | 10 ---------
 PrmPkg/Readme.md                     | 23 +++++++++++++++-----
 5 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.c b/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.c
index f78c682a654b..e2779f5c1786 100644
--- a/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.c
+++ b/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.c
@@ -53,7 +53,6 @@ ProcessPrmModules (
   OUT PRM_ACPI_DESCRIPTION_TABLE          **PrmAcpiDescriptionTable
   )
 {
-  EFI_GUID                                *PlatformGuid;
   EFI_IMAGE_EXPORT_DIRECTORY              *CurrentImageExportDirectory;
   PRM_MODULE_EXPORT_DESCRIPTOR_STRUCT     *CurrentExportDescriptorStruct;
   PRM_ACPI_DESCRIPTION_TABLE              *PrmAcpiTable;
@@ -81,18 +80,17 @@ ProcessPrmModules (
   }
   *PrmAcpiDescriptionTable = NULL;
 
-  PlatformGuid = (EFI_GUID *) PcdGetPtr (PcdPrmPlatformGuid);
   //
-  // The platform should set PcdPrmPlatformGuid to a non-zero value
+  // The platform DSC GUID must be set to a non-zero value
   //
-  if (CompareGuid (PlatformGuid, &gZeroGuid)) {
+  if (CompareGuid (&gEdkiiDscPlatformGuid, &gZeroGuid)) {
     DEBUG ((
       DEBUG_ERROR,
-      "  %a %a: PcdPrmPlatformGuid must be set to a unique value in the platform DSC file.\n",
+      "  %a %a: The Platform GUID in the DSC file must be set to a unique non-zero value.\n",
       _DBGMSGID_,
       __FUNCTION__
       ));
-    ASSERT (!CompareGuid (PlatformGuid, &gZeroGuid));
+    ASSERT (!CompareGuid (&gEdkiiDscPlatformGuid, &gZeroGuid));
   }
 
   DEBUG ((DEBUG_INFO, "  %a %a: %d total PRM modules to process.\n", _DBGMSGID_, __FUNCTION__, mPrmModuleCount));
@@ -118,7 +116,7 @@ ProcessPrmModules (
   PrmAcpiTable->Header.OemRevision      = PcdGet32 (PcdAcpiDefaultOemRevision);
   PrmAcpiTable->Header.CreatorId        = PcdGet32 (PcdAcpiDefaultCreatorId);
   PrmAcpiTable->Header.CreatorRevision  = PcdGet32 (PcdAcpiDefaultCreatorRevision);
-  CopyGuid (&PrmAcpiTable->PrmPlatformGuid, PlatformGuid);
+  CopyGuid (&PrmAcpiTable->PrmPlatformGuid, &gEdkiiDscPlatformGuid);
   PrmAcpiTable->PrmModuleInfoOffset     = OFFSET_OF (PRM_ACPI_DESCRIPTION_TABLE, PrmModuleInfoStructure);
   PrmAcpiTable->PrmModuleInfoCount      = (UINT32) mPrmModuleCount;
 
diff --git a/PrmPkg/Include/PrmExportDescriptor.h b/PrmPkg/Include/PrmExportDescriptor.h
index fc313fd1acc7..76b67a05458a 100644
--- a/PrmPkg/Include/PrmExportDescriptor.h
+++ b/PrmPkg/Include/PrmExportDescriptor.h
@@ -30,6 +30,7 @@ typedef struct {
   UINT64                                Signature;
   UINT16                                Revision;
   UINT16                                NumberPrmHandlers;
+  GUID                                  PlatformGuid;
   GUID                                  ModuleGuid;
 } PRM_MODULE_EXPORT_DESCRIPTOR_STRUCT_HEADER;
 
@@ -98,6 +99,7 @@ typedef struct {
       PRM_MODULE_EXPORT_DESCRIPTOR_SIGNATURE,                                                             \
       PRM_MODULE_EXPORT_REVISION,                                                                         \
       VA_ARG_COUNT(__VA_ARGS__),                                                                          \
+      EDKII_DSC_PLATFORM_GUID,                                                                            \
       EFI_CALLER_ID_GUID                                                                                  \
     },                                                                                                    \
     { __VA_ARGS__ }                                                                                       \
diff --git a/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.inf b/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.inf
index 7efefdae960f..26e7cc169897 100644
--- a/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.inf
+++ b/PrmPkg/PrmLoaderDxe/PrmLoaderDxe.inf
@@ -52,7 +52,6 @@ [Pcd]
   gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiDefaultOemRevision      ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiDefaultCreatorId        ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiDefaultCreatorRevision  ## CONSUMES
-  gPrmPkgTokenSpaceGuid.PcdPrmPlatformGuid                      ## CONSUMES
 
 [Protocols]
   gEfiAcpiTableProtocolGuid
diff --git a/PrmPkg/PrmPkg.dec b/PrmPkg/PrmPkg.dec
index 6753ac624444..94888d1c70a4 100644
--- a/PrmPkg/PrmPkg.dec
+++ b/PrmPkg/PrmPkg.dec
@@ -65,13 +65,3 @@ [PcdsFixedAtBuild]
   #  report PRM handler execution time in the application. If such a TimerLib
   #  instance is not available, set this PCD to FALSE in the package DSC file.
   gPrmPkgTokenSpaceGuid.PcdPrmInfoPrintHandlerExecutionTime|TRUE|BOOLEAN|0x00000003
-
-  ## PRM Platform GUID
-  #
-  #  Uniquely identifies a specific platform targeted for PRM module updates. Each
-  #  platform MUST provide a new GUID. This GUID is checked against the platform
-  #  GUID in the PRM module export descriptor during PRM runtime updates to determine
-  #  if a given PRM module update is valid for a given system. Even if PRM runtime
-  #  updates are not planned for a given platform, this value should still be given
-  #  a unique value in the platform DSC.
-  gPrmPkgTokenSpaceGuid.PcdPrmPlatformGuid|{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}|VOID*|0x00000004
diff --git a/PrmPkg/Readme.md b/PrmPkg/Readme.md
index f340eeb64258..4aec5982af54 100644
--- a/PrmPkg/Readme.md
+++ b/PrmPkg/Readme.md
@@ -13,6 +13,10 @@ to be leveraged by platform firmware with minimal overhead to integrate PRM func
 formal design and is not validated at product quality. The development of this feature is shared in the edk2-staging
 branch to simplify collaboration by allowing direct code contributions and early feedback throughout its development.
 
+> **Use recent edk2/master** - This code makes use of a very recent change in edk2 BaseTools. Specifically, commit
+[b65afdd](https://github.com/tianocore/edk2/commit/b65afdde74d6c1fac1cdbd2efdad23ba26295808). Ensure you have that
+change to build the code in this repo as-is.
+
 > By default, the build makes use of a new ACPI OperationRegion type specifically introduced for PRM called
 `PlatformRtMechanism`. Support for this OperationRegion is planned for the next release of the ACPI specification.
 However, support for `PlatformRtMechanism` is already included in the iASL Compiler/Disassembler for early prototyping
@@ -100,14 +104,21 @@ The following list are the currently defined build flags (if any) that may be pa
 ### PRM Platform GUID
 **IMPORTANT**
 
-A configuration item that requires user attention is the PRM platform GUID. Each platform that uses PRM must be
-uniquely identifiable so that various instances of a PRM module can target the correct platform in PRM module updates.
+PRM has a concept of a "Platform GUID" which associates a specific platform with a set of PRM modules built for
+that platform. This GUID is used to ensure system compatibility for a given collection of PRM modules.
 
-To apply a unique platform GUID set the following PCD to a unique value in your platform DSC file.
-  ``gPrmPkgTokenSpaceGuid.PcdPrmPlatformGuid``
+Therefore, each PRM module must only target a single platform and each platform must have a unique GUID. Even if a
+PRM module is unchanged between two different platforms now, there is no guarantee that will remain the case so always
+assign a unique Platform GUID for each platform.
 
-The default value assigned in [PrmPkg.dec](PrmPkg/PrmPkg.dec) is zero. By design, this is an invalid value that will
-cause an ASSERT if it is not updated.
+The PRM Platform GUID is primarily used during PRM module runtime updates in the OS to ensure that the Platform GUID
+in the system's ACPI table (PRMT) matches the Platform GUID of the module requested for update. Even if runtime
+updates are not a planned feature for a given platform, still assign a unique Platform GUID for binary module
+identification (the Platform GUID is in the module's export descriptor) and to ensure such updates can be seamlessly
+supported in the future if needed.
+
+In the `PrmPkg` implementation, the Platform GUID is automatically derived from the PLATFORM_GUID in the DSC file of
+the package being built.
 
 ## Overview
 At a high-level, PRM can be viewed from three levels of granularity:
-- 
2.28.0.windows.1