MdeModulePkg/Library/VariablePolicyLib/VariablePolicyExtraInitRuntimeDxe.c

   1 /** @file -- VariablePolicyExtraInitRuntimeDxe.c
   2 This file contains extra init and deinit routines that register and unregister
   3 VariableAddressChange callbacks.
   4
   5 Copyright (c) Microsoft Corporation.
   6 SPDX-License-Identifier: BSD-2-Clause-Patent
   7
   8 **/
   9
  10 #include <Library/UefiBootServicesTableLib.h>
  11 #include <Library/UefiRuntimeServicesTableLib.h>
  12
  13 extern EFI_GET_VARIABLE   mGetVariableHelper;
  14 extern UINT8              *mPolicyTable;
  15 STATIC BOOLEAN            mIsVirtualAddrConverted;
  16 STATIC EFI_EVENT          mVariablePolicyLibVirtualAddressChangeEvent  = NULL;
  17
  18 /**
  19   For the RuntimeDxe version of this lib, convert internal pointer addresses to virtual addresses.
  20
  21   @param[in] Event      Event whose notification function is being invoked.
  22   @param[in] Context    The pointer to the notification function's context, which
  23                         is implementation-dependent.
  24 **/
  25 STATIC
  26 VOID
  27 EFIAPI
  28 VariablePolicyLibVirtualAddressCallback (
  29   IN  EFI_EVENT   Event,
  30   IN  VOID        *Context
  31   )
  32 {
  33   gRT->ConvertPointer (0, (VOID **)&mPolicyTable);
  34   gRT->ConvertPointer (0, (VOID **)&mGetVariableHelper);
  35   mIsVirtualAddrConverted = TRUE;
  36 }
  37
  38
  39 /**
  40   An extra init hook that enables the RuntimeDxe library instance to
  41   register VirtualAddress change callbacks. Among other things.
  42
  43   @retval     EFI_SUCCESS   Everything is good. Continue with init.
  44   @retval     Others        Uh... don't continue.
  45
  46 **/
  47 EFI_STATUS
  48 VariablePolicyExtraInit (
  49   VOID
  50   )
  51 {
  52   return gBS->CreateEventEx (EVT_NOTIFY_SIGNAL,
  53                               TPL_NOTIFY,
  54                               VariablePolicyLibVirtualAddressCallback,
  55                               NULL,
  56                               &gEfiEventVirtualAddressChangeGuid,
  57                               &mVariablePolicyLibVirtualAddressChangeEvent);
  58 }
  59
  60
  61 /**
  62   An extra deinit hook that enables the RuntimeDxe library instance to
  63   register VirtualAddress change callbacks. Among other things.
  64
  65   @retval     EFI_SUCCESS   Everything is good. Continue with deinit.
  66   @retval     Others        Uh... don't continue.
  67
  68 **/
  69 EFI_STATUS
  70 VariablePolicyExtraDeinit (
  71   VOID
  72   )
  73 {
  74   EFI_STATUS  Status;
  75
  76   Status = EFI_SUCCESS;
  77   if (mIsVirtualAddrConverted) {
  78     Status = gBS->CloseEvent (mVariablePolicyLibVirtualAddressChangeEvent);
  79   }
  80   else {
  81     Status = EFI_SUCCESS;
  82   }
  83
  84   return Status;
  85 }