EdkCompatibilityPkg/Foundation/Library/EdkIIGlueLib/Library/PeiServicesTablePointerLibMm7/PeiServicesTablePointer.c

   1 /*++
   2
   3 Copyright (c) 2004 - 2006, Intel Corporation. All rights reserved.<BR>
   4 This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12
  13 Module Name:
  14
  15   PeiServicesTablePointer.c
  16
  17 Abstract:
  18
  19   PEI Services Table Pointer Library.
  20
  21 --*/
  22
  23 #include "EdkIIGluePeim.h"
  24
  25 /**
  26   The function returns the pointer to PeiServices.
  27
  28   The function returns the pointer to PeiServices.
  29   It will ASSERT() if the pointer to PeiServices is NULL.
  30
  31   @retval  The pointer to PeiServices.
  32
  33 **/
  34 EFI_PEI_SERVICES **
  35 EFIAPI
  36 GetPeiServicesTablePointer (
  37   VOID
  38   )
  39 {
  40   IA32_DESCRIPTOR   Idtr;
  41   EFI_PEI_SERVICES  **PeiServices;
  42
  43   AsmReadIdtr (&Idtr);
  44   PeiServices = (EFI_PEI_SERVICES **)(UINTN)(*(UINTN*)(Idtr.Base - sizeof (UINTN)));
  45
  46   if ((*PeiServices)->Hdr.Signature == PEI_SERVICES_SIGNATURE) {
  47     return PeiServices;
  48   } else {
  49     PeiServices = (EFI_PEI_SERVICES **)(UINTN)AsmReadMm7 ();
  50     ASSERT (PeiServices != NULL);
  51     return PeiServices;
  52   }
  53 }
  54
  55 /**
  56   The constructor function caches the pointer to PEI services.
  57
  58   The constructor function caches the pointer to PEI services.
  59   It will always return EFI_SUCCESS.
  60
  61   @param  FfsHeader   Pointer to FFS header the loaded driver.
  62   @param  PeiServices Pointer to the PEI services.
  63
  64   @retval EFI_SUCCESS   The constructor always returns EFI_SUCCESS.
  65
  66 **/
  67 EFI_STATUS
  68 EFIAPI
  69 PeiServicesTablePointerLibConstructor (
  70   IN EFI_FFS_FILE_HEADER  *FfsHeader,
  71   IN EFI_PEI_SERVICES     **PeiServices
  72   )
  73 {
  74 #if (PI_SPECIFICATION_VERSION < 0x00010000)
  75   AsmWriteMm7 ((UINT64)(UINTN)PeiServices);
  76 #endif
  77   return EFI_SUCCESS;
  78 }