UEFI Hello world for allocate runtime service data

HelloWorld.c

/** @file
  This sample application bases on HelloWorld PCD setting
  to print "UEFI Hello World!" to the UEFI Console.

  Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <Uefi.h>
#include <Library/PcdLib.h>
#include <Library/UefiLib.h>
#include <Library/UefiApplicationEntryPoint.h>

#include <Library/UefiBootServicesTableLib.h>
#include <Library/DebugLib.h>



EFI_STATUS
EFIAPI
ReserveSharedDataMemory (VOID);

//
// String token ID of help message text.
// Shell supports to find help message in the resource section of an application image if
// .MAN file is not found. This global variable is added to make build tool recognizes
// that the help string is consumed by user and then build tool will add the string into
// the resource section. Thus the application can use '-?' option to show help message in
// Shell.
//
GLOBAL_REMOVE_IF_UNREFERENCED EFI_STRING_ID  mStringHelpTokenId = STRING_TOKEN (STR_HELLO_WORLD_HELP_INFORMATION);

/**
  The user Entry Point for Application. The user code starts with this function
  as the real entry point for the application.

  @param[in] ImageHandle    The firmware allocated handle for the EFI image.
  @param[in] SystemTable    A pointer to the EFI System Table.

  @retval EFI_SUCCESS       The entry point is executed successfully.
  @retval other             Some error occurs when executing this entry point.

**/
EFI_STATUS
EFIAPI
UefiMain (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  UINT32  Index;

  Index = 0;

  //
  // Three PCD type (FeatureFlag, UINT32 and String) are used as the sample.
  //
  if (FeaturePcdGet (PcdHelloWorldPrintEnable)) {
    for (Index = 0; Index < PcdGet32 (PcdHelloWorldPrintTimes); Index++) {
      //
      // Use UefiLib Print API to print string to UEFI console
      //
      Print ((CHAR16 *)PcdGetPtr (PcdHelloWorldPrintString));
    }
  }
  ReserveSharedDataMemory();
  return EFI_SUCCESS;
}

#define SHARED_DATA_SIZE 0x10000 // 64 KB
#define SHARE_DATA_PAGES (SHARED_DATA_SIZE/EFI_PAGE_SIZE)

EFI_STATUS
EFIAPI
ReserveSharedDataMemory (VOID)
{
  EFI_PHYSICAL_ADDRESS phy_addr = { 0 };
  EFI_STATUS Status = gBS->AllocatePages(AllocateAnyPages,
  EfiRuntimeServicesData, 16,
  &phy_addr);
  Print (L"\r\nPhysical 0x%016X\r\n", phy_addr);

  return Status;
}