MdeModulePkg/Universal/FaultTolerantWriteDxe/FaultTolerantWriteSmm.c

   1 /** @file
   2
   3   This is a simple fault tolerant write driver that is intended to use in the SMM environment.
   4
   5   This boot service protocol only provides fault tolerant write capability for
   6   block devices.  The protocol has internal non-volatile intermediate storage
   7   of the data and private information. It should be able to recover
   8   automatically from a critical fault, such as power failure.
   9
  10   The implementation uses an FTW (Fault Tolerant Write) Work Space.
  11   This work space is a memory copy of the work space on the Working Block,
  12   the size of the work space is the FTW_WORK_SPACE_SIZE bytes.
  13
  14   The work space stores each write record as EFI_FTW_RECORD structure.
  15   The spare block stores the write buffer before write to the target block.
  16
  17   The write record has three states to specify the different phase of write operation.
  18   1) WRITE_ALLOCATED is that the record is allocated in write space.
  19      The information of write operation is stored in write record structure.
  20   2) SPARE_COMPLETED is that the data from write buffer is writed into the spare block as the backup.
  21   3) WRITE_COMPLETED is that the data is copied from the spare block to the target block.
  22
  23   This driver operates the data as the whole size of spare block.
  24   It first read the SpareAreaLength data from the target block into the spare memory buffer.
  25   Then copy the write buffer data into the spare memory buffer.
  26   Then write the spare memory buffer into the spare block.
  27   Final copy the data from the spare block to the target block.
  28
  29   To make this drive work well, the following conditions must be satisfied:
  30   1. The write NumBytes data must be fit within Spare area.
  31      Offset + NumBytes <= SpareAreaLength
  32   2. The whole flash range has the same block size.
  33   3. Working block is an area which contains working space in its last block and has the same size as spare block.
  34   4. Working Block area must be in the single one Firmware Volume Block range which FVB protocol is produced on.
  35   5. Spare area must be in the single one Firmware Volume Block range which FVB protocol is produced on.
  36   6. Any write data area (SpareAreaLength Area) which the data will be written into must be
  37      in the single one Firmware Volume Block range which FVB protocol is produced on.
  38   7. If write data area (such as Variable range) is enlarged, the spare area range must be enlarged.
  39      The spare area must be enough large to store the write data before write them into the target range.
  40   If one of them is not satisfied, FtwWrite may fail.
  41   Usually, Spare area only takes one block. That's SpareAreaLength = BlockSize, NumberOfSpareBlock = 1.
  42
  43   Caution: This module requires additional review when modified.
  44   This driver need to make sure the CommBuffer is not in the SMRAM range.
  45
  46 Copyright (c) 2010 - 2018, Intel Corporation. All rights reserved.<BR>
  47 SPDX-License-Identifier: BSD-2-Clause-Patent
  48
  49 **/
  50
  51 #include <PiMm.h>
  52 #include <Library/MmServicesTableLib.h>
  53 #include <Library/BaseLib.h>
  54 #include <Protocol/SmmSwapAddressRange.h>
  55 #include "FaultTolerantWrite.h"
  56 #include "FaultTolerantWriteSmmCommon.h"
  57 #include <Protocol/MmEndOfDxe.h>
  58
  59 VOID            *mFvbRegistration = NULL;
  60 EFI_FTW_DEVICE  *mFtwDevice       = NULL;
  61
  62 ///
  63 /// The flag to indicate whether the platform has left the DXE phase of execution.
  64 ///
  65 BOOLEAN  mEndOfDxe = FALSE;
  66
  67 /**
  68   Retrieve the SMM FVB protocol interface by HANDLE.
  69
  70   @param[in]  FvBlockHandle     The handle of SMM FVB protocol that provides services for
  71                                 reading, writing, and erasing the target block.
  72   @param[out] FvBlock           The interface of SMM FVB protocol
  73
  74   @retval EFI_SUCCESS           The interface information for the specified protocol was returned.
  75   @retval EFI_UNSUPPORTED       The device does not support the SMM FVB protocol.
  76   @retval EFI_INVALID_PARAMETER FvBlockHandle is not a valid EFI_HANDLE or FvBlock is NULL.
  77
  78 **/
  79 EFI_STATUS
  80 FtwGetFvbByHandle (
  81   IN  EFI_HANDLE                          FvBlockHandle,
  82   OUT EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  **FvBlock
  83   )
  84 {
  85   //
  86   // To get the SMM FVB protocol interface on the handle
  87   //
  88   return gMmst->MmHandleProtocol (
  89                   FvBlockHandle,
  90                   &gEfiSmmFirmwareVolumeBlockProtocolGuid,
  91                   (VOID **)FvBlock
  92                   );
  93 }
  94
  95 /**
  96   Retrieve the SMM Swap Address Range protocol interface.
  97
  98   @param[out] SarProtocol       The interface of SMM SAR protocol
  99
 100   @retval EFI_SUCCESS           The SMM SAR protocol instance was found and returned in SarProtocol.
 101   @retval EFI_NOT_FOUND         The SMM SAR protocol instance was not found.
 102   @retval EFI_INVALID_PARAMETER SarProtocol is NULL.
 103
 104 **/
 105 EFI_STATUS
 106 FtwGetSarProtocol (
 107   OUT VOID  **SarProtocol
 108   )
 109 {
 110   EFI_STATUS  Status;
 111
 112   //
 113   // Locate Smm Swap Address Range protocol
 114   //
 115   Status = gMmst->MmLocateProtocol (
 116                     &gEfiSmmSwapAddressRangeProtocolGuid,
 117                     NULL,
 118                     SarProtocol
 119                     );
 120   return Status;
 121 }
 122
 123 /**
 124   Function returns an array of handles that support the SMM FVB protocol
 125   in a buffer allocated from pool.
 126
 127   @param[out]  NumberHandles    The number of handles returned in Buffer.
 128   @param[out]  Buffer           A pointer to the buffer to return the requested
 129                                 array of  handles that support SMM FVB protocol.
 130
 131   @retval EFI_SUCCESS           The array of handles was returned in Buffer, and the number of
 132                                 handles in Buffer was returned in NumberHandles.
 133   @retval EFI_NOT_FOUND         No SMM FVB handle was found.
 134   @retval EFI_OUT_OF_RESOURCES  There is not enough pool memory to store the matching results.
 135   @retval EFI_INVALID_PARAMETER NumberHandles is NULL or Buffer is NULL.
 136
 137 **/
 138 EFI_STATUS
 139 GetFvbCountAndBuffer (
 140   OUT UINTN       *NumberHandles,
 141   OUT EFI_HANDLE  **Buffer
 142   )
 143 {
 144   EFI_STATUS  Status;
 145   UINTN       BufferSize;
 146
 147   if ((NumberHandles == NULL) || (Buffer == NULL)) {
 148     return EFI_INVALID_PARAMETER;
 149   }
 150
 151   BufferSize     = 0;
 152   *NumberHandles = 0;
 153   *Buffer        = NULL;
 154   Status         = gMmst->MmLocateHandle (
 155                             ByProtocol,
 156                             &gEfiSmmFirmwareVolumeBlockProtocolGuid,
 157                             NULL,
 158                             &BufferSize,
 159                             *Buffer
 160                             );
 161   if (EFI_ERROR (Status) && (Status != EFI_BUFFER_TOO_SMALL)) {
 162     return EFI_NOT_FOUND;
 163   }
 164
 165   *Buffer = AllocatePool (BufferSize);
 166   if (*Buffer == NULL) {
 167     return EFI_OUT_OF_RESOURCES;
 168   }
 169
 170   Status = gMmst->MmLocateHandle (
 171                     ByProtocol,
 172                     &gEfiSmmFirmwareVolumeBlockProtocolGuid,
 173                     NULL,
 174                     &BufferSize,
 175                     *Buffer
 176                     );
 177
 178   *NumberHandles = BufferSize / sizeof (EFI_HANDLE);
 179   if (EFI_ERROR (Status)) {
 180     *NumberHandles = 0;
 181     FreePool (*Buffer);
 182     *Buffer = NULL;
 183   }
 184
 185   return Status;
 186 }
 187
 188 /**
 189   Get the handle of the SMM FVB protocol by the FVB base address and attributes.
 190
 191   @param[in]  Address       The base address of SMM FVB protocol.
 192   @param[in]  Attributes    The attributes of the SMM FVB protocol.
 193   @param[out] SmmFvbHandle  The handle of the SMM FVB protocol.
 194
 195   @retval  EFI_SUCCESS    The FVB handle is found.
 196   @retval  EFI_ABORTED    The FVB protocol is not found.
 197
 198 **/
 199 EFI_STATUS
 200 GetFvbByAddressAndAttribute (
 201   IN  EFI_PHYSICAL_ADDRESS  Address,
 202   IN  EFI_FVB_ATTRIBUTES_2  Attributes,
 203   OUT EFI_HANDLE            *SmmFvbHandle
 204   )
 205 {
 206   EFI_STATUS                          Status;
 207   EFI_HANDLE                          *HandleBuffer;
 208   UINTN                               HandleCount;
 209   UINTN                               Index;
 210   EFI_PHYSICAL_ADDRESS                FvbBaseAddress;
 211   EFI_FVB_ATTRIBUTES_2                FvbAttributes;
 212   EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *Fvb;
 213
 214   HandleBuffer = NULL;
 215
 216   //
 217   // Locate all handles of SMM Fvb protocol.
 218   //
 219   Status = GetFvbCountAndBuffer (&HandleCount, &HandleBuffer);
 220   if (EFI_ERROR (Status)) {
 221     return EFI_ABORTED;
 222   }
 223
 224   //
 225   // Find the proper SMM Fvb handle by the address and attributes.
 226   //
 227   for (Index = 0; Index < HandleCount; Index++) {
 228     Status = FtwGetFvbByHandle (HandleBuffer[Index], &Fvb);
 229     if (EFI_ERROR (Status)) {
 230       break;
 231     }
 232
 233     //
 234     // Compare the address.
 235     //
 236     Status = Fvb->GetPhysicalAddress (Fvb, &FvbBaseAddress);
 237     if (EFI_ERROR (Status)) {
 238       continue;
 239     }
 240
 241     if (Address != FvbBaseAddress) {
 242       continue;
 243     }
 244
 245     //
 246     // Compare the attribute.
 247     //
 248     Status = Fvb->GetAttributes (Fvb, &FvbAttributes);
 249     if (EFI_ERROR (Status)) {
 250       continue;
 251     }
 252
 253     if (Attributes != FvbAttributes) {
 254       continue;
 255     }
 256
 257     //
 258     // Found the proper FVB handle.
 259     //
 260     *SmmFvbHandle = HandleBuffer[Index];
 261     FreePool (HandleBuffer);
 262     return EFI_SUCCESS;
 263   }
 264
 265   FreePool (HandleBuffer);
 266   return EFI_ABORTED;
 267 }
 268
 269 /**
 270   Communication service SMI Handler entry.
 271
 272   This SMI handler provides services for the fault tolerant write wrapper driver.
 273
 274   Caution: This function requires additional review when modified.
 275   This driver need to make sure the CommBuffer is not in the SMRAM range.
 276   Also in FTW_FUNCTION_GET_LAST_WRITE case, check SmmFtwGetLastWriteHeader->Data +
 277   SmmFtwGetLastWriteHeader->PrivateDataSize within communication buffer.
 278
 279   @param[in]     DispatchHandle  The unique handle assigned to this handler by SmiHandlerRegister().
 280   @param[in]     RegisterContext Points to an optional handler context which was specified when the
 281                                  handler was registered.
 282   @param[in, out] CommBuffer     A pointer to a collection of data in memory that will be conveyed
 283                                  from a non-SMM environment into an SMM environment.
 284   @param[in, out] CommBufferSize The size of the CommBuffer.
 285
 286   @retval EFI_SUCCESS                         The interrupt was handled and quiesced. No other handlers
 287                                               should still be called.
 288   @retval EFI_WARN_INTERRUPT_SOURCE_QUIESCED  The interrupt has been quiesced but other handlers should
 289                                               still be called.
 290   @retval EFI_WARN_INTERRUPT_SOURCE_PENDING   The interrupt is still pending and other handlers should still
 291                                               be called.
 292   @retval EFI_INTERRUPT_PENDING               The interrupt could not be quiesced.
 293
 294 **/
 295 EFI_STATUS
 296 EFIAPI
 297 SmmFaultTolerantWriteHandler (
 298   IN     EFI_HANDLE  DispatchHandle,
 299   IN     CONST VOID  *RegisterContext,
 300   IN OUT VOID        *CommBuffer,
 301   IN OUT UINTN       *CommBufferSize
 302   )
 303 {
 304   EFI_STATUS                           Status;
 305   SMM_FTW_COMMUNICATE_FUNCTION_HEADER  *SmmFtwFunctionHeader;
 306   SMM_FTW_GET_MAX_BLOCK_SIZE_HEADER    *SmmGetMaxBlockSizeHeader;
 307   SMM_FTW_ALLOCATE_HEADER              *SmmFtwAllocateHeader;
 308   SMM_FTW_WRITE_HEADER                 *SmmFtwWriteHeader;
 309   SMM_FTW_RESTART_HEADER               *SmmFtwRestartHeader;
 310   SMM_FTW_GET_LAST_WRITE_HEADER        *SmmFtwGetLastWriteHeader;
 311   VOID                                 *PrivateData;
 312   EFI_HANDLE                           SmmFvbHandle;
 313   UINTN                                InfoSize;
 314   UINTN                                CommBufferPayloadSize;
 315   UINTN                                PrivateDataSize;
 316   UINTN                                Length;
 317   UINTN                                TempCommBufferSize;
 318
 319   //
 320   // If input is invalid, stop processing this SMI
 321   //
 322   if ((CommBuffer == NULL) || (CommBufferSize == NULL)) {
 323     return EFI_SUCCESS;
 324   }
 325
 326   TempCommBufferSize = *CommBufferSize;
 327
 328   if (TempCommBufferSize < SMM_FTW_COMMUNICATE_HEADER_SIZE) {
 329     DEBUG ((DEBUG_ERROR, "SmmFtwHandler: SMM communication buffer size invalid!\n"));
 330     return EFI_SUCCESS;
 331   }
 332
 333   CommBufferPayloadSize = TempCommBufferSize - SMM_FTW_COMMUNICATE_HEADER_SIZE;
 334
 335   if (!FtwSmmIsBufferOutsideSmmValid ((UINTN)CommBuffer, TempCommBufferSize)) {
 336     DEBUG ((DEBUG_ERROR, "SmmFtwHandler: SMM communication buffer in SMRAM or overflow!\n"));
 337     return EFI_SUCCESS;
 338   }
 339
 340   SmmFtwFunctionHeader = (SMM_FTW_COMMUNICATE_FUNCTION_HEADER *)CommBuffer;
 341
 342   if (mEndOfDxe) {
 343     //
 344     // It will be not safe to expose the operations after End Of Dxe.
 345     //
 346     DEBUG ((DEBUG_ERROR, "SmmFtwHandler: Not safe to do the operation: %x after End Of Dxe, so access denied!\n", SmmFtwFunctionHeader->Function));
 347     SmmFtwFunctionHeader->ReturnStatus = EFI_ACCESS_DENIED;
 348     return EFI_SUCCESS;
 349   }
 350
 351   switch (SmmFtwFunctionHeader->Function) {
 352     case FTW_FUNCTION_GET_MAX_BLOCK_SIZE:
 353       if (CommBufferPayloadSize < sizeof (SMM_FTW_GET_MAX_BLOCK_SIZE_HEADER)) {
 354         DEBUG ((DEBUG_ERROR, "GetMaxBlockSize: SMM communication buffer size invalid!\n"));
 355         return EFI_SUCCESS;
 356       }
 357
 358       SmmGetMaxBlockSizeHeader = (SMM_FTW_GET_MAX_BLOCK_SIZE_HEADER *)SmmFtwFunctionHeader->Data;
 359
 360       Status = FtwGetMaxBlockSize (
 361                  &mFtwDevice->FtwInstance,
 362                  &SmmGetMaxBlockSizeHeader->BlockSize
 363                  );
 364       break;
 365
 366     case FTW_FUNCTION_ALLOCATE:
 367       if (CommBufferPayloadSize < sizeof (SMM_FTW_ALLOCATE_HEADER)) {
 368         DEBUG ((DEBUG_ERROR, "Allocate: SMM communication buffer size invalid!\n"));
 369         return EFI_SUCCESS;
 370       }
 371
 372       SmmFtwAllocateHeader = (SMM_FTW_ALLOCATE_HEADER *)SmmFtwFunctionHeader->Data;
 373       Status               = FtwAllocate (
 374                                &mFtwDevice->FtwInstance,
 375                                &SmmFtwAllocateHeader->CallerId,
 376                                SmmFtwAllocateHeader->PrivateDataSize,
 377                                SmmFtwAllocateHeader->NumberOfWrites
 378                                );
 379       break;
 380
 381     case FTW_FUNCTION_WRITE:
 382       if (CommBufferPayloadSize < OFFSET_OF (SMM_FTW_WRITE_HEADER, Data)) {
 383         DEBUG ((DEBUG_ERROR, "Write: SMM communication buffer size invalid!\n"));
 384         return EFI_SUCCESS;
 385       }
 386
 387       SmmFtwWriteHeader = (SMM_FTW_WRITE_HEADER *)SmmFtwFunctionHeader->Data;
 388       Length            = SmmFtwWriteHeader->Length;
 389       PrivateDataSize   = SmmFtwWriteHeader->PrivateDataSize;
 390       if (((UINTN)(~0) - Length < OFFSET_OF (SMM_FTW_WRITE_HEADER, Data)) ||
 391           ((UINTN)(~0) - PrivateDataSize < OFFSET_OF (SMM_FTW_WRITE_HEADER, Data) + Length))
 392       {
 393         //
 394         // Prevent InfoSize overflow
 395         //
 396         Status = EFI_ACCESS_DENIED;
 397         break;
 398       }
 399
 400       InfoSize = OFFSET_OF (SMM_FTW_WRITE_HEADER, Data) + Length + PrivateDataSize;
 401
 402       //
 403       // SMRAM range check already covered before
 404       //
 405       if (InfoSize > CommBufferPayloadSize) {
 406         DEBUG ((DEBUG_ERROR, "Write: Data size exceed communication buffer size limit!\n"));
 407         Status = EFI_ACCESS_DENIED;
 408         break;
 409       }
 410
 411       if (PrivateDataSize == 0) {
 412         PrivateData = NULL;
 413       } else {
 414         PrivateData = (VOID *)&SmmFtwWriteHeader->Data[Length];
 415       }
 416
 417       Status = GetFvbByAddressAndAttribute (
 418                  SmmFtwWriteHeader->FvbBaseAddress,
 419                  SmmFtwWriteHeader->FvbAttributes,
 420                  &SmmFvbHandle
 421                  );
 422       if (!EFI_ERROR (Status)) {
 423         //
 424         // The SpeculationBarrier() call here is to ensure the previous
 425         // range/content checks for the CommBuffer have been completed before
 426         // calling into FtwWrite().
 427         //
 428         SpeculationBarrier ();
 429         Status = FtwWrite (
 430                    &mFtwDevice->FtwInstance,
 431                    SmmFtwWriteHeader->Lba,
 432                    SmmFtwWriteHeader->Offset,
 433                    Length,
 434                    PrivateData,
 435                    SmmFvbHandle,
 436                    SmmFtwWriteHeader->Data
 437                    );
 438       }
 439
 440       break;
 441
 442     case FTW_FUNCTION_RESTART:
 443       if (CommBufferPayloadSize < sizeof (SMM_FTW_RESTART_HEADER)) {
 444         DEBUG ((DEBUG_ERROR, "Restart: SMM communication buffer size invalid!\n"));
 445         return EFI_SUCCESS;
 446       }
 447
 448       SmmFtwRestartHeader = (SMM_FTW_RESTART_HEADER *)SmmFtwFunctionHeader->Data;
 449       Status              = GetFvbByAddressAndAttribute (
 450                               SmmFtwRestartHeader->FvbBaseAddress,
 451                               SmmFtwRestartHeader->FvbAttributes,
 452                               &SmmFvbHandle
 453                               );
 454       if (!EFI_ERROR (Status)) {
 455         Status = FtwRestart (&mFtwDevice->FtwInstance, SmmFvbHandle);
 456       }
 457
 458       break;
 459
 460     case FTW_FUNCTION_ABORT:
 461       Status = FtwAbort (&mFtwDevice->FtwInstance);
 462       break;
 463
 464     case FTW_FUNCTION_GET_LAST_WRITE:
 465       if (CommBufferPayloadSize < OFFSET_OF (SMM_FTW_GET_LAST_WRITE_HEADER, Data)) {
 466         DEBUG ((DEBUG_ERROR, "GetLastWrite: SMM communication buffer size invalid!\n"));
 467         return EFI_SUCCESS;
 468       }
 469
 470       SmmFtwGetLastWriteHeader = (SMM_FTW_GET_LAST_WRITE_HEADER *)SmmFtwFunctionHeader->Data;
 471       PrivateDataSize          = SmmFtwGetLastWriteHeader->PrivateDataSize;
 472       if ((UINTN)(~0) - PrivateDataSize < OFFSET_OF (SMM_FTW_GET_LAST_WRITE_HEADER, Data)) {
 473         //
 474         // Prevent InfoSize overflow
 475         //
 476         Status = EFI_ACCESS_DENIED;
 477         break;
 478       }
 479
 480       InfoSize = OFFSET_OF (SMM_FTW_GET_LAST_WRITE_HEADER, Data) + PrivateDataSize;
 481
 482       //
 483       // SMRAM range check already covered before
 484       //
 485       if (InfoSize > CommBufferPayloadSize) {
 486         DEBUG ((DEBUG_ERROR, "Data size exceed communication buffer size limit!\n"));
 487         Status = EFI_ACCESS_DENIED;
 488         break;
 489       }
 490
 491       Status = FtwGetLastWrite (
 492                  &mFtwDevice->FtwInstance,
 493                  &SmmFtwGetLastWriteHeader->CallerId,
 494                  &SmmFtwGetLastWriteHeader->Lba,
 495                  &SmmFtwGetLastWriteHeader->Offset,
 496                  &SmmFtwGetLastWriteHeader->Length,
 497                  &PrivateDataSize,
 498                  (VOID *)SmmFtwGetLastWriteHeader->Data,
 499                  &SmmFtwGetLastWriteHeader->Complete
 500                  );
 501       SmmFtwGetLastWriteHeader->PrivateDataSize = PrivateDataSize;
 502       break;
 503
 504     default:
 505       Status = EFI_UNSUPPORTED;
 506   }
 507
 508   SmmFtwFunctionHeader->ReturnStatus = Status;
 509
 510   return EFI_SUCCESS;
 511 }
 512
 513 /**
 514   SMM Firmware Volume Block Protocol notification event handler.
 515
 516   @param[in]  Protocol      Points to the protocol's unique identifier
 517   @param[in]  Interface     Points to the interface instance
 518   @param[in]  Handle        The handle on which the interface was installed
 519
 520   @retval EFI_SUCCESS       SmmEventCallback runs successfully
 521
 522  **/
 523 EFI_STATUS
 524 EFIAPI
 525 FvbNotificationEvent (
 526   IN CONST EFI_GUID  *Protocol,
 527   IN VOID            *Interface,
 528   IN EFI_HANDLE      Handle
 529   )
 530 {
 531   EFI_STATUS                             Status;
 532   EFI_SMM_FAULT_TOLERANT_WRITE_PROTOCOL  *FtwProtocol;
 533   EFI_HANDLE                             SmmFtwHandle;
 534
 535   //
 536   // Just return to avoid install SMM FaultTolerantWriteProtocol again
 537   // if SMM Fault Tolerant Write protocol had been installed.
 538   //
 539   Status = gMmst->MmLocateProtocol (
 540                     &gEfiSmmFaultTolerantWriteProtocolGuid,
 541                     NULL,
 542                     (VOID **)&FtwProtocol
 543                     );
 544   if (!EFI_ERROR (Status)) {
 545     return EFI_SUCCESS;
 546   }
 547
 548   //
 549   // Found proper FVB protocol and initialize FtwDevice for protocol installation
 550   //
 551   Status = InitFtwProtocol (mFtwDevice);
 552   if (EFI_ERROR (Status)) {
 553     return Status;
 554   }
 555
 556   //
 557   // Install protocol interface
 558   //
 559   Status = gMmst->MmInstallProtocolInterface (
 560                     &mFtwDevice->Handle,
 561                     &gEfiSmmFaultTolerantWriteProtocolGuid,
 562                     EFI_NATIVE_INTERFACE,
 563                     &mFtwDevice->FtwInstance
 564                     );
 565   ASSERT_EFI_ERROR (Status);
 566
 567   ///
 568   /// Register SMM FTW SMI handler
 569   ///
 570   Status = gMmst->MmiHandlerRegister (SmmFaultTolerantWriteHandler, &gEfiSmmFaultTolerantWriteProtocolGuid, &SmmFtwHandle);
 571   ASSERT_EFI_ERROR (Status);
 572
 573   //
 574   // Notify the Ftw wrapper driver SMM Ftw is ready
 575   //
 576   FtwNotifySmmReady ();
 577
 578   return EFI_SUCCESS;
 579 }
 580
 581 /**
 582   SMM END_OF_DXE protocol notification event handler.
 583
 584   @param  Protocol   Points to the protocol's unique identifier
 585   @param  Interface  Points to the interface instance
 586   @param  Handle     The handle on which the interface was installed
 587
 588   @retval EFI_SUCCESS   SmmEndOfDxeCallback runs successfully
 589
 590 **/
 591 EFI_STATUS
 592 EFIAPI
 593 MmEndOfDxeCallback (
 594   IN CONST EFI_GUID  *Protocol,
 595   IN VOID            *Interface,
 596   IN EFI_HANDLE      Handle
 597   )
 598 {
 599   mEndOfDxe = TRUE;
 600   return EFI_SUCCESS;
 601 }
 602
 603 /**
 604   Shared entry point of the module
 605
 606   @retval EFI_SUCCESS           The initialization finished successfully.
 607   @retval EFI_OUT_OF_RESOURCES  Allocate memory error
 608   @retval EFI_INVALID_PARAMETER Workspace or Spare block does not exist
 609 **/
 610 EFI_STATUS
 611 MmFaultTolerantWriteInitialize (
 612   VOID
 613   )
 614 {
 615   EFI_STATUS  Status;
 616   VOID        *MmEndOfDxeRegistration;
 617
 618   //
 619   // Allocate private data structure for SMM FTW protocol and do some initialization
 620   //
 621   Status = InitFtwDevice (&mFtwDevice);
 622   if (EFI_ERROR (Status)) {
 623     return Status;
 624   }
 625
 626   //
 627   // Register EFI_SMM_END_OF_DXE_PROTOCOL_GUID notify function.
 628   //
 629   Status = gMmst->MmRegisterProtocolNotify (
 630                     &gEfiMmEndOfDxeProtocolGuid,
 631                     MmEndOfDxeCallback,
 632                     &MmEndOfDxeRegistration
 633                     );
 634   ASSERT_EFI_ERROR (Status);
 635
 636   //
 637   // Register FvbNotificationEvent () notify function.
 638   //
 639   Status = gMmst->MmRegisterProtocolNotify (
 640                     &gEfiSmmFirmwareVolumeBlockProtocolGuid,
 641                     FvbNotificationEvent,
 642                     &mFvbRegistration
 643                     );
 644   ASSERT_EFI_ERROR (Status);
 645
 646   FvbNotificationEvent (NULL, NULL, NULL);
 647
 648   return EFI_SUCCESS;
 649 }