UefiPayloadPkg/Library/PayloadEntryHelperLib/PayloadEntryHelperLib.c

/** @file

  Copyright (c) 2010, Apple Inc. All rights reserved.<BR>
  Copyright (c) 2017 - 2021, Intel Corporation. All rights reserved.<BR>
  Copyright (c) Microsoft Corporation.

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

**/

#include <PiPei.h>

#include <Library/HobLib.h>
#include <Library/DebugLib.h>
#include <Library/PayloadEntryHelperLib.h>

/**
  Add a new HOB to the HOB List.

  @param HobType            Type of the new HOB.
  @param HobLength          Length of the new HOB to allocate.

  @return  NULL if there is no space to create a hob.
  @return  The address point to the new created hob.

**/
VOID *
EFIAPI
CreateHob (
  IN  UINT16  HobType,
  IN  UINT16  HobLength
  )
{
  EFI_HOB_HANDOFF_INFO_TABLE  *HandOffHob;
  EFI_HOB_GENERIC_HEADER      *HobEnd;
  EFI_PHYSICAL_ADDRESS        FreeMemory;
  VOID                        *Hob;

  HandOffHob = GetHobList ();
  if (HandOffHob == NULL) {
    ASSERT (HandOffHob != NULL);
    return NULL;
  }

  //
  // Check Length to avoid data overflow.
  //
  if (HobLength > MAX_UINT16 - 0x7) {
    return NULL;
  }

  HobLength = (UINT16)((HobLength + 0x7) & (~0x7));

  FreeMemory = HandOffHob->EfiFreeMemoryTop - HandOffHob->EfiFreeMemoryBottom;

  if (FreeMemory < HobLength) {
    return NULL;
  }

  Hob                                        = (VOID *)(UINTN)HandOffHob->EfiEndOfHobList;
  ((EFI_HOB_GENERIC_HEADER *)Hob)->HobType   = HobType;
  ((EFI_HOB_GENERIC_HEADER *)Hob)->HobLength = HobLength;
  ((EFI_HOB_GENERIC_HEADER *)Hob)->Reserved  = 0;

  HobEnd                      = (EFI_HOB_GENERIC_HEADER *)((UINTN)Hob + HobLength);
  HandOffHob->EfiEndOfHobList = (EFI_PHYSICAL_ADDRESS)(UINTN)HobEnd;

  HobEnd->HobType   = EFI_HOB_TYPE_END_OF_HOB_LIST;
  HobEnd->HobLength = sizeof (EFI_HOB_GENERIC_HEADER);
  HobEnd->Reserved  = 0;
  HobEnd++;
  HandOffHob->EfiFreeMemoryBottom = (EFI_PHYSICAL_ADDRESS)(UINTN)HobEnd;

  return Hob;
}