MdePkg/Library/SmmServicesTableLib/SmmServicesTableLib.c

   1 /** @file
   2   SMM Services Table Library.
   3
   4   Copyright (c) 2009, Intel Corporation<BR>
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include <PiDxe.h>
  16 #include <PiSmm.h>
  17 #include <Protocol/SmmBase2.h>
  18 #include <Library/UefiBootServicesTableLib.h>
  19 #include <Library/SmmServicesTableLib.h>
  20 #include <Library/DebugLib.h>
  21
  22 EFI_SMM_SYSTEM_TABLE2        *gSmst              = NULL;
  23 EFI_SMM_BASE2_PROTOCOL       *mInternalSmmBase2  = NULL;
  24
  25
  26 /**
  27   The constructor function caches the pointer of Smm Services Table.
  28
  29   @param  ImageHandle   The firmware allocated handle for the EFI image.
  30   @param  SystemTable   A pointer to the EFI System Table.
  31
  32   @retval EFI_SUCCESS   The constructor always returns EFI_SUCCESS.
  33
  34 **/
  35 EFI_STATUS
  36 EFIAPI
  37 SmmServicesTableLibConstructor (
  38   IN EFI_HANDLE        ImageHandle,
  39   IN EFI_SYSTEM_TABLE  *SystemTable
  40   )
  41 {
  42   EFI_STATUS                   Status;
  43   BOOLEAN                      InSmm;
  44
  45   //
  46   // Retrieve SMM Base2 Protocol
  47   //
  48   Status = gBS->LocateProtocol (
  49                   &gEfiSmmBase2ProtocolGuid,
  50                   NULL,
  51                   (VOID **) &mInternalSmmBase2
  52                   );
  53   ASSERT_EFI_ERROR (Status);
  54   ASSERT (mInternalSmmBase2 != NULL);
  55
  56   //
  57   // Check to see if we are already in SMM
  58   //
  59   mInternalSmmBase2->InSmm (mInternalSmmBase2, &InSmm);
  60
  61   if (!InSmm) {
  62     //
  63     // We are not in SMM, so SMST is not needed
  64     //
  65     return EFI_SUCCESS;
  66   }
  67
  68   //
  69   // We are in SMM, retrieve the pointer to SMM System Table
  70   //
  71   mInternalSmmBase2->GetSmstLocation (mInternalSmmBase2, &gSmst);
  72
  73   ASSERT (gSmst != NULL);
  74
  75   return EFI_SUCCESS;
  76 }
  77
  78
  79 /**
  80   This function allows the caller to determine if the driver is executing in
  81   System Management Mode(SMM).
  82
  83   This function returns TRUE if the driver is executing in SMM and FALSE if the
  84   driver is not executing in SMM.
  85
  86   @retval  TRUE  The driver is executing in System Management Mode (SMM).
  87   @retval  FALSE The driver is not executing in System Management Mode (SMM).
  88
  89 **/
  90 BOOLEAN
  91 EFIAPI
  92 InSmm (
  93   VOID
  94   )
  95 {
  96   BOOLEAN                      InSmm;
  97
  98   //
  99   // Check to see if we are already in SMM
 100   //
 101   mInternalSmmBase2->InSmm (mInternalSmmBase2, &InSmm);
 102
 103   return InSmm;
 104 }