UefiPayloadPkg/Library/DxeHobListLib/DxeHobListLib.c

   1 /** @file
   2   This library retrieve the EFI_BOOT_SERVICES pointer from EFI system table in
   3   library's constructor.
   4
   5   Copyright (c) 2021, Intel Corporation. All rights reserved.<BR>
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7
   8 **/
   9
  10
  11 #include <Uefi.h>
  12
  13 VOID  *gHobList = NULL;
  14
  15 /**
  16   Local implementation of GUID comparasion that doesn't depend on DebugLib::ASSERT().
  17
  18   This function compares Guid1 to Guid2.  If the GUIDs are identical then TRUE is returned.
  19   If there are any bit differences in the two GUIDs, then FALSE is returned.
  20
  21   @param  Guid1       A pointer to a 128 bit GUID.
  22   @param  Guid2       A pointer to a 128 bit GUID.
  23
  24   @retval TRUE        Guid1 and Guid2 are identical.
  25   @retval FALSE       Guid1 and Guid2 are not identical.
  26 **/
  27 BOOLEAN
  28 LocalCompareGuid (
  29   IN CONST GUID  *Guid1,
  30   IN CONST GUID  *Guid2
  31   )
  32 {
  33   UINT64  *Left;
  34   UINT64  *Right;
  35
  36   Left  = (UINT64 *) Guid1;
  37   Right = (UINT64 *) Guid2;
  38
  39   return (BOOLEAN) (Left[0] == Right[0] && Left[1] == Right[1]);
  40 }
  41
  42 /**
  43   @param  ImageHandle   The firmware allocated handle for the EFI image.
  44   @param  SystemTable   A pointer to the EFI System Table.
  45
  46   @retval EFI_SUCCESS   The constructor always returns EFI_SUCCESS.
  47
  48 **/
  49 EFI_STATUS
  50 EFIAPI
  51 DxeHobListLibConstructor (
  52   IN EFI_HANDLE        ImageHandle,
  53   IN EFI_SYSTEM_TABLE  *SystemTable
  54   )
  55 {
  56   UINTN             Index;
  57
  58   for (Index = 0; Index < SystemTable->NumberOfTableEntries; Index++) {
  59     if (LocalCompareGuid (&gEfiHobListGuid, &SystemTable->ConfigurationTable[Index].VendorGuid)) {
  60       gHobList = SystemTable->ConfigurationTable[Index].VendorTable;
  61       return EFI_SUCCESS;
  62     }
  63   }
  64
  65   return EFI_NOT_FOUND;
  66 }