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 /**
 190   Get the handle of the SMM FVB protocol by the FVB base address and attributes.
 191
 192   @param[in]  Address       The base address of SMM FVB protocol.
 193   @param[in]  Attributes    The attributes of the SMM FVB protocol.
 194   @param[out] SmmFvbHandle  The handle of the SMM FVB protocol.
 195
 196   @retval  EFI_SUCCESS    The FVB handle is found.
 197   @retval  EFI_ABORTED    The FVB protocol is not found.
 198
 199 **/
 200 EFI_STATUS
 201 GetFvbByAddressAndAttribute (
 202   IN  EFI_PHYSICAL_ADDRESS            Address,
 203   IN  EFI_FVB_ATTRIBUTES_2            Attributes,
 204   OUT EFI_HANDLE                      *SmmFvbHandle
 205   )
 206 {
 207   EFI_STATUS                          Status;
 208   EFI_HANDLE                          *HandleBuffer;
 209   UINTN                               HandleCount;
 210   UINTN                               Index;
 211   EFI_PHYSICAL_ADDRESS                FvbBaseAddress;
 212   EFI_FVB_ATTRIBUTES_2                FvbAttributes;
 213   EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *Fvb;
 214
 215   HandleBuffer = NULL;
 216
 217   //
 218   // Locate all handles of SMM Fvb protocol.
 219   //
 220   Status = GetFvbCountAndBuffer (&HandleCount, &HandleBuffer);
 221   if (EFI_ERROR (Status)) {
 222     return EFI_ABORTED;
 223   }
 224
 225   //
 226   // Find the proper SMM Fvb handle by the address and attributes.
 227   //
 228   for (Index = 0; Index < HandleCount; Index++) {
 229     Status = FtwGetFvbByHandle (HandleBuffer[Index], &Fvb);
 230     if (EFI_ERROR (Status)) {
 231       break;
 232     }
 233     //
 234     // Compare the address.
 235     //
 236     Status = Fvb->GetPhysicalAddress (Fvb, &FvbBaseAddress);
 237     if (EFI_ERROR (Status)) {
 238       continue;
 239     }
 240     if (Address != FvbBaseAddress) {
 241      continue;
 242     }
 243
 244     //
 245     // Compare the attribute.
 246     //
 247     Status = Fvb->GetAttributes (Fvb, &FvbAttributes);
 248     if (EFI_ERROR (Status)) {
 249       continue;
 250     }
 251     if (Attributes != FvbAttributes) {
 252      continue;
 253     }
 254
 255     //
 256     // Found the proper FVB handle.
 257     //
 258     *SmmFvbHandle = HandleBuffer[Index];
 259     FreePool (HandleBuffer);
 260     return EFI_SUCCESS;
 261   }
 262
 263   FreePool (HandleBuffer);
 264   return EFI_ABORTED;
 265 }
 266
 267 /**
 268   Communication service SMI Handler entry.
 269
 270   This SMI handler provides services for the fault tolerant write wrapper driver.
 271
 272   Caution: This function requires additional review when modified.
 273   This driver need to make sure the CommBuffer is not in the SMRAM range.
 274   Also in FTW_FUNCTION_GET_LAST_WRITE case, check SmmFtwGetLastWriteHeader->Data +
 275   SmmFtwGetLastWriteHeader->PrivateDataSize within communication buffer.
 276
 277   @param[in]     DispatchHandle  The unique handle assigned to this handler by SmiHandlerRegister().
 278   @param[in]     RegisterContext Points to an optional handler context which was specified when the
 279                                  handler was registered.
 280   @param[in, out] CommBuffer     A pointer to a collection of data in memory that will be conveyed
 281                                  from a non-SMM environment into an SMM environment.
 282   @param[in, out] CommBufferSize The size of the CommBuffer.
 283
 284   @retval EFI_SUCCESS                         The interrupt was handled and quiesced. No other handlers
 285                                               should still be called.
 286   @retval EFI_WARN_INTERRUPT_SOURCE_QUIESCED  The interrupt has been quiesced but other handlers should
 287                                               still be called.
 288   @retval EFI_WARN_INTERRUPT_SOURCE_PENDING   The interrupt is still pending and other handlers should still
 289                                               be called.
 290   @retval EFI_INTERRUPT_PENDING               The interrupt could not be quiesced.
 291
 292 **/
 293 EFI_STATUS
 294 EFIAPI
 295 SmmFaultTolerantWriteHandler (
 296   IN     EFI_HANDLE                                DispatchHandle,
 297   IN     CONST VOID                                *RegisterContext,
 298   IN OUT VOID                                      *CommBuffer,
 299   IN OUT UINTN                                     *CommBufferSize
 300   )
 301 {
 302   EFI_STATUS                                       Status;
 303   SMM_FTW_COMMUNICATE_FUNCTION_HEADER              *SmmFtwFunctionHeader;
 304   SMM_FTW_GET_MAX_BLOCK_SIZE_HEADER                *SmmGetMaxBlockSizeHeader;
 305   SMM_FTW_ALLOCATE_HEADER                          *SmmFtwAllocateHeader;
 306   SMM_FTW_WRITE_HEADER                             *SmmFtwWriteHeader;
 307   SMM_FTW_RESTART_HEADER                           *SmmFtwRestartHeader;
 308   SMM_FTW_GET_LAST_WRITE_HEADER                    *SmmFtwGetLastWriteHeader;
 309   VOID                                             *PrivateData;
 310   EFI_HANDLE                                       SmmFvbHandle;
 311   UINTN                                            InfoSize;
 312   UINTN                                            CommBufferPayloadSize;
 313   UINTN                                            PrivateDataSize;
 314   UINTN                                            Length;
 315   UINTN                                            TempCommBufferSize;
 316
 317   //
 318   // If input is invalid, stop processing this SMI
 319   //
 320   if (CommBuffer == NULL || CommBufferSize == NULL) {
 321     return EFI_SUCCESS;
 322   }
 323
 324   TempCommBufferSize = *CommBufferSize;
 325
 326   if (TempCommBufferSize < SMM_FTW_COMMUNICATE_HEADER_SIZE) {
 327     DEBUG ((EFI_D_ERROR, "SmmFtwHandler: SMM communication buffer size invalid!\n"));
 328     return EFI_SUCCESS;
 329   }
 330   CommBufferPayloadSize = TempCommBufferSize - SMM_FTW_COMMUNICATE_HEADER_SIZE;
 331
 332   if (!FtwSmmIsBufferOutsideSmmValid ((UINTN)CommBuffer, TempCommBufferSize)) {
 333     DEBUG ((EFI_D_ERROR, "SmmFtwHandler: SMM communication buffer in SMRAM or overflow!\n"));
 334     return EFI_SUCCESS;
 335   }
 336
 337   SmmFtwFunctionHeader = (SMM_FTW_COMMUNICATE_FUNCTION_HEADER *)CommBuffer;
 338
 339   if (mEndOfDxe) {
 340     //
 341     // It will be not safe to expose the operations after End Of Dxe.
 342     //
 343     DEBUG ((EFI_D_ERROR, "SmmFtwHandler: Not safe to do the operation: %x after End Of Dxe, so access denied!\n", SmmFtwFunctionHeader->Function));
 344     SmmFtwFunctionHeader->ReturnStatus = EFI_ACCESS_DENIED;
 345     return EFI_SUCCESS;
 346   }
 347
 348   switch (SmmFtwFunctionHeader->Function) {
 349     case FTW_FUNCTION_GET_MAX_BLOCK_SIZE:
 350       if (CommBufferPayloadSize < sizeof (SMM_FTW_GET_MAX_BLOCK_SIZE_HEADER)) {
 351         DEBUG ((EFI_D_ERROR, "GetMaxBlockSize: SMM communication buffer size invalid!\n"));
 352         return EFI_SUCCESS;
 353       }
 354       SmmGetMaxBlockSizeHeader = (SMM_FTW_GET_MAX_BLOCK_SIZE_HEADER *) SmmFtwFunctionHeader->Data;
 355
 356       Status = FtwGetMaxBlockSize (
 357                  &mFtwDevice->FtwInstance,
 358                  &SmmGetMaxBlockSizeHeader->BlockSize
 359                  );
 360       break;
 361
 362     case FTW_FUNCTION_ALLOCATE:
 363       if (CommBufferPayloadSize < sizeof (SMM_FTW_ALLOCATE_HEADER)) {
 364         DEBUG ((EFI_D_ERROR, "Allocate: SMM communication buffer size invalid!\n"));
 365         return EFI_SUCCESS;
 366       }
 367       SmmFtwAllocateHeader = (SMM_FTW_ALLOCATE_HEADER *) SmmFtwFunctionHeader->Data;
 368       Status = FtwAllocate (
 369                  &mFtwDevice->FtwInstance,
 370                  &SmmFtwAllocateHeader->CallerId,
 371                  SmmFtwAllocateHeader->PrivateDataSize,
 372                  SmmFtwAllocateHeader->NumberOfWrites
 373                  );
 374       break;
 375
 376     case FTW_FUNCTION_WRITE:
 377       if (CommBufferPayloadSize < OFFSET_OF (SMM_FTW_WRITE_HEADER, Data)) {
 378         DEBUG ((EFI_D_ERROR, "Write: SMM communication buffer size invalid!\n"));
 379         return EFI_SUCCESS;
 380       }
 381       SmmFtwWriteHeader = (SMM_FTW_WRITE_HEADER *) SmmFtwFunctionHeader->Data;
 382       Length = SmmFtwWriteHeader->Length;
 383       PrivateDataSize = SmmFtwWriteHeader->PrivateDataSize;
 384       if (((UINTN)(~0) - Length < OFFSET_OF (SMM_FTW_WRITE_HEADER, Data)) ||
 385         ((UINTN)(~0) - PrivateDataSize < OFFSET_OF (SMM_FTW_WRITE_HEADER, Data) + Length)) {
 386         //
 387         // Prevent InfoSize overflow
 388         //
 389         Status = EFI_ACCESS_DENIED;
 390         break;
 391       }
 392       InfoSize = OFFSET_OF (SMM_FTW_WRITE_HEADER, Data) + Length + PrivateDataSize;
 393
 394       //
 395       // SMRAM range check already covered before
 396       //
 397       if (InfoSize > CommBufferPayloadSize) {
 398         DEBUG ((EFI_D_ERROR, "Write: Data size exceed communication buffer size limit!\n"));
 399         Status = EFI_ACCESS_DENIED;
 400         break;
 401       }
 402
 403       if (PrivateDataSize == 0) {
 404         PrivateData = NULL;
 405       } else {
 406         PrivateData = (VOID *)&SmmFtwWriteHeader->Data[Length];
 407       }
 408       Status = GetFvbByAddressAndAttribute (
 409                  SmmFtwWriteHeader->FvbBaseAddress,
 410                  SmmFtwWriteHeader->FvbAttributes,
 411                  &SmmFvbHandle
 412                  );
 413       if (!EFI_ERROR (Status)) {
 414         //
 415         // The SpeculationBarrier() call here is to ensure the previous
 416         // range/content checks for the CommBuffer have been completed before
 417         // calling into FtwWrite().
 418         //
 419         SpeculationBarrier ();
 420         Status = FtwWrite(
 421                    &mFtwDevice->FtwInstance,
 422                    SmmFtwWriteHeader->Lba,
 423                    SmmFtwWriteHeader->Offset,
 424                    Length,
 425                    PrivateData,
 426                    SmmFvbHandle,
 427                    SmmFtwWriteHeader->Data
 428                    );
 429       }
 430       break;
 431
 432     case FTW_FUNCTION_RESTART:
 433       if (CommBufferPayloadSize < sizeof (SMM_FTW_RESTART_HEADER)) {
 434         DEBUG ((EFI_D_ERROR, "Restart: SMM communication buffer size invalid!\n"));
 435         return EFI_SUCCESS;
 436       }
 437       SmmFtwRestartHeader = (SMM_FTW_RESTART_HEADER *) SmmFtwFunctionHeader->Data;
 438       Status = GetFvbByAddressAndAttribute (
 439                  SmmFtwRestartHeader->FvbBaseAddress,
 440                  SmmFtwRestartHeader->FvbAttributes,
 441                  &SmmFvbHandle
 442                  );
 443       if (!EFI_ERROR (Status)) {
 444         Status = FtwRestart (&mFtwDevice->FtwInstance, SmmFvbHandle);
 445       }
 446       break;
 447
 448     case FTW_FUNCTION_ABORT:
 449       Status = FtwAbort (&mFtwDevice->FtwInstance);
 450       break;
 451
 452     case FTW_FUNCTION_GET_LAST_WRITE:
 453       if (CommBufferPayloadSize < OFFSET_OF (SMM_FTW_GET_LAST_WRITE_HEADER, Data)) {
 454         DEBUG ((EFI_D_ERROR, "GetLastWrite: SMM communication buffer size invalid!\n"));
 455         return EFI_SUCCESS;
 456       }
 457       SmmFtwGetLastWriteHeader = (SMM_FTW_GET_LAST_WRITE_HEADER *) SmmFtwFunctionHeader->Data;
 458       PrivateDataSize = SmmFtwGetLastWriteHeader->PrivateDataSize;
 459       if ((UINTN)(~0) - PrivateDataSize < OFFSET_OF (SMM_FTW_GET_LAST_WRITE_HEADER, Data)){
 460         //
 461         // Prevent InfoSize overflow
 462         //
 463         Status = EFI_ACCESS_DENIED;
 464         break;
 465       }
 466       InfoSize = OFFSET_OF (SMM_FTW_GET_LAST_WRITE_HEADER, Data) + PrivateDataSize;
 467
 468       //
 469       // SMRAM range check already covered before
 470       //
 471       if (InfoSize > CommBufferPayloadSize) {
 472         DEBUG ((EFI_D_ERROR, "Data size exceed communication buffer size limit!\n"));
 473         Status = EFI_ACCESS_DENIED;
 474         break;
 475       }
 476
 477       Status = FtwGetLastWrite (
 478                  &mFtwDevice->FtwInstance,
 479                  &SmmFtwGetLastWriteHeader->CallerId,
 480                  &SmmFtwGetLastWriteHeader->Lba,
 481                  &SmmFtwGetLastWriteHeader->Offset,
 482                  &SmmFtwGetLastWriteHeader->Length,
 483                  &PrivateDataSize,
 484                  (VOID *)SmmFtwGetLastWriteHeader->Data,
 485                  &SmmFtwGetLastWriteHeader->Complete
 486                  );
 487       SmmFtwGetLastWriteHeader->PrivateDataSize = PrivateDataSize;
 488       break;
 489
 490     default:
 491       Status = EFI_UNSUPPORTED;
 492   }
 493
 494   SmmFtwFunctionHeader->ReturnStatus = Status;
 495
 496   return EFI_SUCCESS;
 497 }
 498
 499
 500 /**
 501   SMM Firmware Volume Block Protocol notification event handler.
 502
 503   @param[in]  Protocol      Points to the protocol's unique identifier
 504   @param[in]  Interface     Points to the interface instance
 505   @param[in]  Handle        The handle on which the interface was installed
 506
 507   @retval EFI_SUCCESS       SmmEventCallback runs successfully
 508
 509  **/
 510 EFI_STATUS
 511 EFIAPI
 512 FvbNotificationEvent (
 513   IN CONST EFI_GUID                       *Protocol,
 514   IN VOID                                 *Interface,
 515   IN EFI_HANDLE                           Handle
 516   )
 517 {
 518   EFI_STATUS                              Status;
 519   EFI_SMM_FAULT_TOLERANT_WRITE_PROTOCOL   *FtwProtocol;
 520   EFI_HANDLE                              SmmFtwHandle;
 521
 522   //
 523   // Just return to avoid install SMM FaultTolerantWriteProtocol again
 524   // if SMM Fault Tolerant Write protocol had been installed.
 525   //
 526   Status = gMmst->MmLocateProtocol (
 527                     &gEfiSmmFaultTolerantWriteProtocolGuid,
 528                     NULL,
 529                     (VOID **) &FtwProtocol
 530                     );
 531   if (!EFI_ERROR (Status)) {
 532     return EFI_SUCCESS;
 533   }
 534
 535   //
 536   // Found proper FVB protocol and initialize FtwDevice for protocol installation
 537   //
 538   Status = InitFtwProtocol (mFtwDevice);
 539   if (EFI_ERROR(Status)) {
 540     return Status;
 541   }
 542
 543   //
 544   // Install protocol interface
 545   //
 546   Status = gMmst->MmInstallProtocolInterface (
 547                     &mFtwDevice->Handle,
 548                     &gEfiSmmFaultTolerantWriteProtocolGuid,
 549                     EFI_NATIVE_INTERFACE,
 550                     &mFtwDevice->FtwInstance
 551                     );
 552   ASSERT_EFI_ERROR (Status);
 553
 554   ///
 555   /// Register SMM FTW SMI handler
 556   ///
 557   Status = gMmst->MmiHandlerRegister (SmmFaultTolerantWriteHandler, &gEfiSmmFaultTolerantWriteProtocolGuid, &SmmFtwHandle);
 558   ASSERT_EFI_ERROR (Status);
 559
 560   //
 561   // Notify the Ftw wrapper driver SMM Ftw is ready
 562   //
 563   FtwNotifySmmReady ();
 564
 565   return EFI_SUCCESS;
 566 }
 567
 568 /**
 569   SMM END_OF_DXE protocol notification event handler.
 570
 571   @param  Protocol   Points to the protocol's unique identifier
 572   @param  Interface  Points to the interface instance
 573   @param  Handle     The handle on which the interface was installed
 574
 575   @retval EFI_SUCCESS   SmmEndOfDxeCallback runs successfully
 576
 577 **/
 578 EFI_STATUS
 579 EFIAPI
 580 MmEndOfDxeCallback (
 581   IN CONST EFI_GUID                       *Protocol,
 582   IN VOID                                 *Interface,
 583   IN EFI_HANDLE                           Handle
 584   )
 585 {
 586   mEndOfDxe = TRUE;
 587   return EFI_SUCCESS;
 588 }
 589
 590 /**
 591   Shared entry point of the module
 592
 593   @retval EFI_SUCCESS           The initialization finished successfully.
 594   @retval EFI_OUT_OF_RESOURCES  Allocate memory error
 595   @retval EFI_INVALID_PARAMETER Workspace or Spare block does not exist
 596 **/
 597 EFI_STATUS
 598 MmFaultTolerantWriteInitialize (
 599   VOID
 600   )
 601 {
 602   EFI_STATUS                              Status;
 603   VOID                                    *MmEndOfDxeRegistration;
 604
 605   //
 606   // Allocate private data structure for SMM FTW protocol and do some initialization
 607   //
 608   Status = InitFtwDevice (&mFtwDevice);
 609   if (EFI_ERROR(Status)) {
 610     return Status;
 611   }
 612
 613   //
 614   // Register EFI_SMM_END_OF_DXE_PROTOCOL_GUID notify function.
 615   //
 616   Status = gMmst->MmRegisterProtocolNotify (
 617                     &gEfiMmEndOfDxeProtocolGuid,
 618                     MmEndOfDxeCallback,
 619                     &MmEndOfDxeRegistration
 620                     );
 621   ASSERT_EFI_ERROR (Status);
 622
 623   //
 624   // Register FvbNotificationEvent () notify function.
 625   //
 626   Status = gMmst->MmRegisterProtocolNotify (
 627                     &gEfiSmmFirmwareVolumeBlockProtocolGuid,
 628                     FvbNotificationEvent,
 629                     &mFvbRegistration
 630                     );
 631   ASSERT_EFI_ERROR (Status);
 632
 633   FvbNotificationEvent (NULL, NULL, NULL);
 634
 635   return EFI_SUCCESS;
 636 }