StandaloneMmPkg: MM driver entry point library.

This patch implements module entry point library for Standalone
management mode (MM) Drivers.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Supreeth Venkatesh <supreeth.venkatesh@arm.com>
Reviewed-by: Achin Gupta <achin.gupta@arm.com>
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>
Signed-off-by: Sughosh Ganu <sughosh.ganu@arm.com>

StandaloneMmPkg/Library/StandaloneMmDriverEntryPoint/StandaloneMmDriverEntryPoint.c

@@ -0,0 +1,99 @@
+/** @file
+  Entry point to a Standalone MM driver.
+
+Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2016 - 2018, ARM Ltd. All rights reserved.<BR>
+
+This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution.  The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <PiMm.h>
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+
+VOID
+EFIAPI
+ProcessLibraryConstructorList (
+  IN EFI_HANDLE               ImageHandle,
+  IN IN EFI_MM_SYSTEM_TABLE   *MmSystemTable
+  );
+
+EFI_STATUS
+EFIAPI
+ProcessModuleEntryPointList (
+  IN EFI_HANDLE               ImageHandle,
+  IN IN EFI_MM_SYSTEM_TABLE   *MmSystemTable
+  );
+
+VOID
+EFIAPI
+ProcessLibraryDestructorList (
+  IN EFI_HANDLE               ImageHandle,
+  IN IN EFI_MM_SYSTEM_TABLE   *MmSystemTable
+  );
+
+/**
+  The entry point of PE/COFF Image for a Standalone MM Driver.
+
+  This function is the entry point for a Standalone MM Driver.
+  This function must call ProcessLibraryConstructorList() and
+  ProcessModuleEntryPointList().
+  If the return status from ProcessModuleEntryPointList()
+  is an error status, then ProcessLibraryDestructorList() must be called.
+  The return value from ProcessModuleEntryPointList() is returned.
+  If _gDriverUnloadImageCount is greater than zero, then an unload
+  handler must be registered for this image
+  and the unload handler must invoke ProcessModuleUnloadList().
+  If _gUefiDriverRevision is not zero and SystemTable->Hdr.Revision is less
+  than _gUefiDriverRevison, then return EFI_INCOMPATIBLE_VERSION.
+
+
+  @param  ImageHandle  The image handle of the Standalone MM Driver.
+  @param  SystemTable  A pointer to the EFI System Table.
+
+  @retval  EFI_SUCCESS               The Standalone MM Driver exited normally.
+  @retval  EFI_INCOMPATIBLE_VERSION  _gUefiDriverRevision is greater than
+                                    SystemTable->Hdr.Revision.
+  @retval  Other                     Return value from ProcessModuleEntryPointList().
+
+**/
+EFI_STATUS
+EFIAPI
+_ModuleEntryPoint (
+  IN EFI_HANDLE               ImageHandle,
+  IN IN EFI_MM_SYSTEM_TABLE   *MmSystemTable
+  )
+{
+  EFI_STATUS                 Status;
+
+  //
+  // Call constructor for all libraries
+  //
+  ProcessLibraryConstructorList (ImageHandle, MmSystemTable);
+
+  //
+  // Call the driver entry point
+  //
+  Status = ProcessModuleEntryPointList (ImageHandle, MmSystemTable);
+
+  //
+  // If all of the drivers returned errors, then invoke all of the library destructors
+  //
+  if (EFI_ERROR (Status)) {
+    ProcessLibraryDestructorList (ImageHandle, MmSystemTable);
+  }
+
+  //
+  // Return the cumulative return status code from all of the driver entry points
+  //
+  return Status;
+}
+