Restore original algorithm and add comments

[mirror_edk2.git] / MdePkg / Library / UefiRuntimeLib / RuntimeLib.c

/**@file\r
  Library utility functions for Runtime driver.\r
\r
Copyright (c) 2006 Intel Corporation. <BR>\r
All rights reserved. This program and the accompanying materials\r
are licensed and made available under the terms and conditions of the BSD License\r
which accompanies this distribution.  The full text of the license may be found at\r
http://opensource.org/licenses/bsd-license.php\r
\r
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include <RuntimeLibInternal.h>\r
\r
///\r
/// Driver Lib Module Globals\r
///\r
\r
STATIC EFI_EVENT              mEfiVirtualNotifyEvent;\r
STATIC EFI_EVENT              mEfiExitBootServicesEvent;\r
STATIC BOOLEAN                mEfiGoneVirtual         = FALSE;\r
STATIC BOOLEAN                mEfiAtRuntime           = FALSE;\r
EFI_RUNTIME_SERVICES          *mRT;\r
\r
/**\r
  Set AtRuntime flag as TRUE after ExitBootServices\r
\r
  @param[in]  Event   The Event that is being processed\r
  @param[in]  Context Event Context\r
**/\r
STATIC\r
VOID\r
EFIAPI\r
RuntimeLibExitBootServicesEvent (\r
  IN EFI_EVENT        Event,\r
  IN VOID             *Context\r
  )\r
{\r
  //\r
  // Clear out BootService globals\r
  //\r
  gBS             = NULL;\r
\r
  mEfiAtRuntime = TRUE;\r
}\r
\r
/**\r
  Fixup internal data so that EFI can be call in virtual mode.\r
  Call the passed in Child Notify event and convert any pointers in\r
  lib to virtual mode.\r
\r
  @param[in]    Event   The Event that is being processed\r
  @param[in]    Context Event Context\r
**/\r
STATIC\r
VOID\r
EFIAPI\r
RuntimeLibVirtualNotifyEvent (\r
  IN EFI_EVENT        Event,\r
  IN VOID             *Context\r
  )\r
{\r
  //\r
  // Update global for Runtime Services Table and IO\r
  //\r
  EfiConvertPointer (0, (VOID **) &mRT);\r
\r
  mEfiGoneVirtual = TRUE;\r
}\r
\r
/**\r
  Intialize runtime Driver Lib if it has not yet been initialized.\r
\r
  @param[in]  ImageHandle   The firmware allocated handle for the EFI image.\r
  @param[in]  SystemTable   A pointer to the EFI System Table.\r
\r
  @return     EFI_STATUS    always returns EFI_SUCCESS except EFI_ALREADY_STARTED if already started.\r
**/\r
EFI_STATUS\r
EFIAPI\r
RuntimeDriverLibConstruct (\r
  IN EFI_HANDLE           ImageHandle,\r
  IN EFI_SYSTEM_TABLE     *SystemTable\r
  )\r
{\r
  EFI_STATUS  Status;\r
\r
  mRT = gRT;\r
  ASSERT (mRT != NULL);\r
  \r
  //\r
  // Register SetVirtualAddressMap () notify function\r
  //\r
  ASSERT (gBS != NULL);\r
  Status = gBS->CreateEvent (\r
                  EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE,\r
                  TPL_NOTIFY,\r
                  RuntimeLibVirtualNotifyEvent,\r
                  NULL,\r
                  &mEfiVirtualNotifyEvent\r
                  );\r
\r
  ASSERT_EFI_ERROR (Status);\r
\r
  Status = gBS->CreateEvent (\r
                  EVT_SIGNAL_EXIT_BOOT_SERVICES,\r
                  TPL_NOTIFY,\r
                  RuntimeLibExitBootServicesEvent,\r
                  NULL,\r
                  &mEfiExitBootServicesEvent\r
                  );\r
\r
  ASSERT_EFI_ERROR (Status);\r
\r
  return Status;\r
}\r
\r
/**\r
  This routine will free some resources which have been allocated in\r
  EfiInitializeRuntimeDriverLib(). If a runtime driver exits with an error,\r
  it must call this routine to free the allocated resource before the exiting.\r
\r
  @retval     EFI_SUCCESS       Shutdown the Runtime Driver Lib successfully\r
  @retval     EFI_UNSUPPORTED   Runtime Driver lib was not initialized at all\r
**/\r
EFI_STATUS\r
EFIAPI\r
RuntimeDriverLibDeconstruct (\r
  IN EFI_HANDLE        ImageHandle,\r
  IN EFI_SYSTEM_TABLE  *SystemTable\r
  )\r
{\r
  EFI_STATUS  Status;\r
\r
  //\r
  // Close SetVirtualAddressMap () notify function\r
  //\r
  ASSERT (gBS != NULL);\r
  Status = gBS->CloseEvent (mEfiVirtualNotifyEvent);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  Status = gBS->CloseEvent (mEfiExitBootServicesEvent);\r
  ASSERT_EFI_ERROR (Status);\r
\r
  return Status;\r
}\r
\r
/**\r
  Return TRUE if ExitBootServices () has been called\r
\r
  @retval TRUE If ExitBootServices () has been called\r
**/\r
BOOLEAN\r
EFIAPI\r
EfiAtRuntime (\r
  VOID\r
  )\r
{\r
  return mEfiAtRuntime;\r
}\r
\r
/**\r
  Return TRUE if SetVirtualAddressMap () has been called\r
\r
  @retval TRUE  If SetVirtualAddressMap () has been called\r
**/\r
BOOLEAN\r
EFIAPI\r
EfiGoneVirtual (\r
  VOID\r
  )\r
{\r
  return mEfiGoneVirtual;\r
}\r
\r