LoadBelow4G.c

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#include <Uefi.h>
#include <Library/BaseLib.h>
#include <Library/UefiDriverEntryPoint.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/PeCoffLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/DxeServicesLib.h>
#include <Library/CacheMaintenanceLib.h>
#include <Library/UefiLib.h>
 
EFI_STATUS
RelocateImageUnder4GIfNeeded (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS                    Status;
  UINT8                         *Buffer;
  UINTN                         BufferSize;
  EFI_HANDLE                    NewImageHandle;
  UINTN                         Pages;
  EFI_PHYSICAL_ADDRESS          FfsBuffer;
  PE_COFF_LOADER_IMAGE_CONTEXT  ImageContext;
  VOID                          *Interface;
 
  //
  // If it is already <4G, no need do relocate
  //
  if ((UINTN)RelocateImageUnder4GIfNeeded < 0xFFFFFFFF) {
    return EFI_SUCCESS;
  }
 
  //
  // If locate gEfiCallerIdGuid success, it means 2nd entry.
  //
  Status = gBS->LocateProtocol (&gEfiCallerIdGuid, NULL, &Interface);
  if (!EFI_ERROR (Status)) {
    DEBUG ((DEBUG_INFO, "FspNotifyDxe - 2nd entry\n"));
    return EFI_SUCCESS;
  }
 
  DEBUG ((DEBUG_INFO, "FspNotifyDxe - 1st entry\n"));
 
  //
  // Here we install a dummy handle
  //
  NewImageHandle = NULL;
  Status         = gBS->InstallProtocolInterface (
                          &NewImageHandle,
                          &gEfiCallerIdGuid,
                          EFI_NATIVE_INTERFACE,
                          NULL
                          );
  ASSERT_EFI_ERROR (Status);
 
  //
  // Reload image itself to <4G mem
  //
  Status = GetSectionFromAnyFv (
             &gEfiCallerIdGuid,
             EFI_SECTION_PE32,
             0,
             (VOID **)&Buffer,
             &BufferSize
             );
  ASSERT_EFI_ERROR (Status);
  ImageContext.Handle    = Buffer;
  ImageContext.ImageRead = PeCoffLoaderImageReadFromMemory;
  //
  // Get information about the image being loaded
  //
  Status = PeCoffLoaderGetImageInfo (&ImageContext);
  ASSERT_EFI_ERROR (Status);
  if (ImageContext.SectionAlignment > EFI_PAGE_SIZE) {
    Pages = EFI_SIZE_TO_PAGES ((UINTN)(ImageContext.ImageSize + ImageContext.SectionAlignment));
  } else {
    Pages = EFI_SIZE_TO_PAGES ((UINTN)ImageContext.ImageSize);
  }
 
  FfsBuffer = 0xFFFFFFFF;
  Status    = gBS->AllocatePages (
                     AllocateMaxAddress,
                     EfiBootServicesCode,
                     Pages,
                     &FfsBuffer
                     );
  ASSERT_EFI_ERROR (Status);
  ImageContext.ImageAddress = (PHYSICAL_ADDRESS)(UINTN)FfsBuffer;
  //
  // Align buffer on section boundary
  //
  ImageContext.ImageAddress += ImageContext.SectionAlignment - 1;
  ImageContext.ImageAddress &= ~((EFI_PHYSICAL_ADDRESS)ImageContext.SectionAlignment - 1);
  //
  // Load the image to our new buffer
  //
  Status = PeCoffLoaderLoadImage (&ImageContext);
  ASSERT_EFI_ERROR (Status);
 
  //
  // Relocate the image in our new buffer
  //
  Status = PeCoffLoaderRelocateImage (&ImageContext);
  ASSERT_EFI_ERROR (Status);
 
  //
  // Free the buffer allocated by ReadSection since the image has been relocated in the new buffer
  //
  gBS->FreePool (Buffer);
 
  //
  // Flush the instruction cache so the image data is written before we execute it
  //
  InvalidateInstructionCacheRange ((VOID *)(UINTN)ImageContext.ImageAddress, (UINTN)ImageContext.ImageSize);
 
  DEBUG ((DEBUG_INFO, "Loading driver at 0x%08x EntryPoint=0x%08x\n", (UINTN)ImageContext.ImageAddress, (UINTN)ImageContext.EntryPoint));
  Status = ((EFI_IMAGE_ENTRY_POINT)(UINTN)(ImageContext.EntryPoint))(NewImageHandle, gST);
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "Error: Image at 0x%08x start failed: %r\n", ImageContext.ImageAddress, Status));
    gBS->FreePages (FfsBuffer, Pages);
  }
 
  //
  // return error to unload >4G copy, if we already relocate itself to <4G.
  //
  return EFI_ALREADY_STARTED;
}