SecurityPkg/VariableAuthenticated/RuntimeDxe/VariableSmm.c

   1 /** @file
   2   The sample implementation for SMM variable protocol. And this driver
   3   implements an SMI handler to communicate with the DXE runtime driver
   4   to provide variable services.
   5
   6   Caution: This module requires additional review when modified.
   7   This driver will have external input - variable data and communicate buffer in SMM mode.
   8   This external input must be validated carefully to avoid security issue like
   9   buffer overflow, integer overflow.
  10
  11   SmmVariableHandler() will receive untrusted input and do basic validation.
  12
  13   Each sub function VariableServiceGetVariable(), VariableServiceGetNextVariableName(),
  14   VariableServiceSetVariable(), VariableServiceQueryVariableInfo(), ReclaimForOS(),
  15   SmmVariableGetStatistics() should also do validation based on its own knowledge.
  16
  17 Copyright (c) 2010 - 2012, Intel Corporation. All rights reserved.<BR>
  18 This program and the accompanying materials
  19 are licensed and made available under the terms and conditions of the BSD License
  20 which accompanies this distribution.  The full text of the license may be found at
  21 http://opensource.org/licenses/bsd-license.php
  22
  23 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  24 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  25
  26 **/
  27
  28 #include <Protocol/SmmVariable.h>
  29 #include <Protocol/SmmFirmwareVolumeBlock.h>
  30 #include <Protocol/SmmFaultTolerantWrite.h>
  31 #include <Protocol/SmmAccess2.h>
  32
  33 #include <Library/SmmServicesTableLib.h>
  34
  35 #include <Guid/AuthenticatedVariableFormat.h>
  36 #include <Guid/SmmVariableCommon.h>
  37 #include "Variable.h"
  38
  39 EFI_SMRAM_DESCRIPTOR                                 *mSmramRanges;
  40 UINTN                                                mSmramRangeCount;
  41
  42 extern VARIABLE_INFO_ENTRY                           *gVariableInfo;
  43 EFI_HANDLE                                           mSmmVariableHandle      = NULL;
  44 EFI_HANDLE                                           mVariableHandle         = NULL;
  45 BOOLEAN                                              mAtRuntime              = FALSE;
  46 EFI_GUID                                             mZeroGuid               = {0, 0, 0, {0, 0, 0, 0, 0, 0, 0, 0}};
  47
  48 EFI_SMM_VARIABLE_PROTOCOL      gSmmVariable = {
  49   VariableServiceGetVariable,
  50   VariableServiceGetNextVariableName,
  51   VariableServiceSetVariable,
  52   VariableServiceQueryVariableInfo
  53 };
  54
  55
  56 /**
  57   Return TRUE if ExitBootServices () has been called.
  58
  59   @retval TRUE If ExitBootServices () has been called.
  60 **/
  61 BOOLEAN
  62 AtRuntime (
  63   VOID
  64   )
  65 {
  66   return mAtRuntime;
  67 }
  68
  69 /**
  70   This function check if the address is in SMRAM.
  71
  72   @param Buffer  the buffer address to be checked.
  73   @param Length  the buffer length to be checked.
  74
  75   @retval TRUE  this address is in SMRAM.
  76   @retval FALSE this address is NOT in SMRAM.
  77 **/
  78 BOOLEAN
  79 InternalIsAddressInSmram (
  80   IN EFI_PHYSICAL_ADDRESS  Buffer,
  81   IN UINT64                Length
  82   )
  83 {
  84   UINTN  Index;
  85
  86   for (Index = 0; Index < mSmramRangeCount; Index ++) {
  87     if (((Buffer >= mSmramRanges[Index].CpuStart) && (Buffer < mSmramRanges[Index].CpuStart + mSmramRanges[Index].PhysicalSize)) ||
  88         ((mSmramRanges[Index].CpuStart >= Buffer) && (mSmramRanges[Index].CpuStart < Buffer + Length))) {
  89       return TRUE;
  90     }
  91   }
  92
  93   return FALSE;
  94 }
  95
  96
  97 /**
  98   Initializes a basic mutual exclusion lock.
  99
 100   This function initializes a basic mutual exclusion lock to the released state
 101   and returns the lock.  Each lock provides mutual exclusion access at its task
 102   priority level.  Since there is no preemption or multiprocessor support in EFI,
 103   acquiring the lock only consists of raising to the locks TPL.
 104   If Lock is NULL, then ASSERT().
 105   If Priority is not a valid TPL value, then ASSERT().
 106
 107   @param  Lock       A pointer to the lock data structure to initialize.
 108   @param  Priority   EFI TPL is associated with the lock.
 109
 110   @return The lock.
 111
 112 **/
 113 EFI_LOCK *
 114 InitializeLock (
 115   IN OUT EFI_LOCK                         *Lock,
 116   IN EFI_TPL                              Priority
 117   )
 118 {
 119   return Lock;
 120 }
 121
 122 /**
 123   Acquires lock only at boot time. Simply returns at runtime.
 124
 125   This is a temperary function that will be removed when
 126   EfiAcquireLock() in UefiLib can handle the call in UEFI
 127   Runtimer driver in RT phase.
 128   It calls EfiAcquireLock() at boot time, and simply returns
 129   at runtime.
 130
 131   @param  Lock         A pointer to the lock to acquire.
 132
 133 **/
 134 VOID
 135 AcquireLockOnlyAtBootTime (
 136   IN EFI_LOCK                             *Lock
 137   )
 138 {
 139
 140 }
 141
 142
 143 /**
 144   Releases lock only at boot time. Simply returns at runtime.
 145
 146   This is a temperary function which will be removed when
 147   EfiReleaseLock() in UefiLib can handle the call in UEFI
 148   Runtimer driver in RT phase.
 149   It calls EfiReleaseLock() at boot time and simply returns
 150   at runtime.
 151
 152   @param  Lock         A pointer to the lock to release.
 153
 154 **/
 155 VOID
 156 ReleaseLockOnlyAtBootTime (
 157   IN EFI_LOCK                             *Lock
 158   )
 159 {
 160
 161 }
 162
 163 /**
 164   Retrive the SMM Fault Tolerent Write protocol interface.
 165
 166   @param[out] FtwProtocol       The interface of SMM Ftw protocol
 167
 168   @retval EFI_SUCCESS           The SMM FTW protocol instance was found and returned in FtwProtocol.
 169   @retval EFI_NOT_FOUND         The SMM FTW protocol instance was not found.
 170   @retval EFI_INVALID_PARAMETER SarProtocol is NULL.
 171
 172 **/
 173 EFI_STATUS
 174 GetFtwProtocol (
 175   OUT VOID                                **FtwProtocol
 176   )
 177 {
 178   EFI_STATUS                              Status;
 179
 180   //
 181   // Locate Smm Fault Tolerent Write protocol
 182   //
 183   Status = gSmst->SmmLocateProtocol (
 184                     &gEfiSmmFaultTolerantWriteProtocolGuid,
 185                     NULL,
 186                     FtwProtocol
 187                     );
 188   return Status;
 189 }
 190
 191
 192 /**
 193   Retrive the SMM FVB protocol interface by HANDLE.
 194
 195   @param[in]  FvBlockHandle     The handle of SMM FVB protocol that provides services for
 196                                 reading, writing, and erasing the target block.
 197   @param[out] FvBlock           The interface of SMM FVB protocol
 198
 199   @retval EFI_SUCCESS           The interface information for the specified protocol was returned.
 200   @retval EFI_UNSUPPORTED       The device does not support the SMM FVB protocol.
 201   @retval EFI_INVALID_PARAMETER FvBlockHandle is not a valid EFI_HANDLE or FvBlock is NULL.
 202
 203 **/
 204 EFI_STATUS
 205 GetFvbByHandle (
 206   IN  EFI_HANDLE                          FvBlockHandle,
 207   OUT EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  **FvBlock
 208   )
 209 {
 210   //
 211   // To get the SMM FVB protocol interface on the handle
 212   //
 213   return gSmst->SmmHandleProtocol (
 214                   FvBlockHandle,
 215                   &gEfiSmmFirmwareVolumeBlockProtocolGuid,
 216                   (VOID **) FvBlock
 217                   );
 218 }
 219
 220
 221 /**
 222   Function returns an array of handles that support the SMM FVB protocol
 223   in a buffer allocated from pool.
 224
 225   @param[out]  NumberHandles    The number of handles returned in Buffer.
 226   @param[out]  Buffer           A pointer to the buffer to return the requested
 227                                 array of  handles that support SMM FVB protocol.
 228
 229   @retval EFI_SUCCESS           The array of handles was returned in Buffer, and the number of
 230                                 handles in Buffer was returned in NumberHandles.
 231   @retval EFI_NOT_FOUND         No SMM FVB handle was found.
 232   @retval EFI_OUT_OF_RESOURCES  There is not enough pool memory to store the matching results.
 233   @retval EFI_INVALID_PARAMETER NumberHandles is NULL or Buffer is NULL.
 234
 235 **/
 236 EFI_STATUS
 237 GetFvbCountAndBuffer (
 238   OUT UINTN                               *NumberHandles,
 239   OUT EFI_HANDLE                          **Buffer
 240   )
 241 {
 242   EFI_STATUS                              Status;
 243   UINTN                                   BufferSize;
 244
 245   if ((NumberHandles == NULL) || (Buffer == NULL)) {
 246     return EFI_INVALID_PARAMETER;
 247   }
 248
 249   BufferSize     = 0;
 250   *NumberHandles = 0;
 251   *Buffer        = NULL;
 252   Status = gSmst->SmmLocateHandle (
 253                     ByProtocol,
 254                     &gEfiSmmFirmwareVolumeBlockProtocolGuid,
 255                     NULL,
 256                     &BufferSize,
 257                     *Buffer
 258                     );
 259   if (EFI_ERROR(Status) && Status != EFI_BUFFER_TOO_SMALL) {
 260     return EFI_NOT_FOUND;
 261   }
 262
 263   *Buffer = AllocatePool (BufferSize);
 264   if (*Buffer == NULL) {
 265     return EFI_OUT_OF_RESOURCES;
 266   }
 267
 268   Status = gSmst->SmmLocateHandle (
 269                     ByProtocol,
 270                     &gEfiSmmFirmwareVolumeBlockProtocolGuid,
 271                     NULL,
 272                     &BufferSize,
 273                     *Buffer
 274                     );
 275
 276   *NumberHandles = BufferSize / sizeof(EFI_HANDLE);
 277   if (EFI_ERROR(Status)) {
 278     *NumberHandles = 0;
 279   }
 280
 281   return Status;
 282 }
 283
 284
 285 /**
 286   Get the variable statistics information from the information buffer pointed by gVariableInfo.
 287
 288   Caution: This function may be invoked at SMM runtime.
 289   InfoEntry and InfoSize are external input. Care must be taken to make sure not security issue at runtime.
 290
 291   @param[in, out]  InfoEntry    A pointer to the buffer of variable information entry.
 292                                 On input, point to the variable information returned last time. if
 293                                 InfoEntry->VendorGuid is zero, return the first information.
 294                                 On output, point to the next variable information.
 295   @param[in, out]  InfoSize     On input, the size of the variable information buffer.
 296                                 On output, the returned variable information size.
 297
 298   @retval EFI_SUCCESS           The variable information is found and returned successfully.
 299   @retval EFI_UNSUPPORTED       No variable inoformation exists in variable driver. The
 300                                 PcdVariableCollectStatistics should be set TRUE to support it.
 301   @retval EFI_BUFFER_TOO_SMALL  The buffer is too small to hold the next variable information.
 302   @retval EFI_INVALID_PARAMETER Input parameter is invalid.
 303
 304 **/
 305 EFI_STATUS
 306 SmmVariableGetStatistics (
 307   IN OUT VARIABLE_INFO_ENTRY                           *InfoEntry,
 308   IN OUT UINTN                                         *InfoSize
 309   )
 310 {
 311   VARIABLE_INFO_ENTRY                                  *VariableInfo;
 312   UINTN                                                NameLength;
 313   UINTN                                                StatisticsInfoSize;
 314   CHAR16                                               *InfoName;
 315
 316   if (InfoEntry == NULL) {
 317     return EFI_INVALID_PARAMETER;
 318   }
 319
 320   VariableInfo = gVariableInfo;
 321   if (VariableInfo == NULL) {
 322     return EFI_UNSUPPORTED;
 323   }
 324
 325   StatisticsInfoSize = sizeof (VARIABLE_INFO_ENTRY) + StrSize (VariableInfo->Name);
 326   if (*InfoSize < StatisticsInfoSize) {
 327     *InfoSize = StatisticsInfoSize;
 328     return EFI_BUFFER_TOO_SMALL;
 329   }
 330   InfoName = (CHAR16 *)(InfoEntry + 1);
 331
 332   if (CompareGuid (&InfoEntry->VendorGuid, &mZeroGuid)) {
 333     //
 334     // Return the first variable info
 335     //
 336     CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY));
 337     CopyMem (InfoName, VariableInfo->Name, StrSize (VariableInfo->Name));
 338     *InfoSize = StatisticsInfoSize;
 339     return EFI_SUCCESS;
 340   }
 341
 342   //
 343   // Get the next variable info
 344   //
 345   while (VariableInfo != NULL) {
 346     if (CompareGuid (&VariableInfo->VendorGuid, &InfoEntry->VendorGuid)) {
 347       NameLength = StrSize (VariableInfo->Name);
 348       if (NameLength == StrSize (InfoName)) {
 349         if (CompareMem (VariableInfo->Name, InfoName, NameLength) == 0) {
 350           //
 351           // Find the match one
 352           //
 353           VariableInfo = VariableInfo->Next;
 354           break;
 355         }
 356       }
 357     }
 358     VariableInfo = VariableInfo->Next;
 359   };
 360
 361   if (VariableInfo == NULL) {
 362     *InfoSize = 0;
 363     return EFI_SUCCESS;
 364   }
 365
 366   //
 367   // Output the new variable info
 368   //
 369   StatisticsInfoSize = sizeof (VARIABLE_INFO_ENTRY) + StrSize (VariableInfo->Name);
 370   if (*InfoSize < StatisticsInfoSize) {
 371     *InfoSize = StatisticsInfoSize;
 372     return EFI_BUFFER_TOO_SMALL;
 373   }
 374
 375   CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY));
 376   CopyMem (InfoName, VariableInfo->Name, StrSize (VariableInfo->Name));
 377   *InfoSize = StatisticsInfoSize;
 378
 379   return EFI_SUCCESS;
 380 }
 381
 382
 383 /**
 384   Communication service SMI Handler entry.
 385
 386   This SMI handler provides services for the variable wrapper driver.
 387
 388   Caution: This function may receive untrusted input.
 389   This variable data and communicate buffer are external input, so this function will do basic validation.
 390   Each sub function VariableServiceGetVariable(), VariableServiceGetNextVariableName(),
 391   VariableServiceSetVariable(), VariableServiceQueryVariableInfo(), ReclaimForOS(),
 392   SmmVariableGetStatistics() should also do validation based on its own knowledge.
 393
 394   @param[in]     DispatchHandle  The unique handle assigned to this handler by SmiHandlerRegister().
 395   @param[in]     RegisterContext Points to an optional handler context which was specified when the
 396                                  handler was registered.
 397   @param[in, out] CommBuffer     A pointer to a collection of data in memory that will
 398                                  be conveyed from a non-SMM environment into an SMM environment.
 399   @param[in, out] CommBufferSize The size of the CommBuffer.
 400
 401   @retval EFI_SUCCESS                         The interrupt was handled and quiesced. No other handlers
 402                                               should still be called.
 403   @retval EFI_WARN_INTERRUPT_SOURCE_QUIESCED  The interrupt has been quiesced but other handlers should
 404                                               still be called.
 405   @retval EFI_WARN_INTERRUPT_SOURCE_PENDING   The interrupt is still pending and other handlers should still
 406                                               be called.
 407   @retval EFI_INTERRUPT_PENDING               The interrupt could not be quiesced.
 408
 409 **/
 410 EFI_STATUS
 411 EFIAPI
 412 SmmVariableHandler (
 413   IN     EFI_HANDLE                                DispatchHandle,
 414   IN     CONST VOID                                *RegisterContext,
 415   IN OUT VOID                                      *CommBuffer,
 416   IN OUT UINTN                                     *CommBufferSize
 417   )
 418 {
 419   EFI_STATUS                                       Status;
 420   SMM_VARIABLE_COMMUNICATE_HEADER                  *SmmVariableFunctionHeader;
 421   SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE         *SmmVariableHeader;
 422   SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME  *GetNextVariableName;
 423   SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO     *QueryVariableInfo;
 424   VARIABLE_INFO_ENTRY                              *VariableInfo;
 425   UINTN                                            InfoSize;
 426
 427   //
 428   // If input is invalid, stop processing this SMI
 429   //
 430   if (CommBuffer == NULL || CommBufferSize == NULL) {
 431     return EFI_SUCCESS;
 432   }
 433
 434   if (*CommBufferSize < SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
 435     return EFI_SUCCESS;
 436   }
 437
 438   if (InternalIsAddressInSmram ((EFI_PHYSICAL_ADDRESS)(UINTN)CommBuffer, *CommBufferSize)) {
 439     DEBUG ((EFI_D_ERROR, "SMM communication buffer size is in SMRAM!\n"));
 440     return EFI_SUCCESS;
 441   }
 442
 443   SmmVariableFunctionHeader = (SMM_VARIABLE_COMMUNICATE_HEADER *)CommBuffer;
 444
 445   switch (SmmVariableFunctionHeader->Function) {
 446     case SMM_VARIABLE_FUNCTION_GET_VARIABLE:
 447       SmmVariableHeader = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *) SmmVariableFunctionHeader->Data;
 448       InfoSize = OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)
 449                  + SmmVariableHeader->DataSize + SmmVariableHeader->NameSize;
 450
 451       //
 452       // SMRAM range check already covered before
 453       //
 454       if (InfoSize > *CommBufferSize - SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
 455         DEBUG ((EFI_D_ERROR, "Data size exceed communication buffer size limit!\n"));
 456         Status = EFI_ACCESS_DENIED;
 457         goto EXIT;
 458       }
 459
 460       Status = VariableServiceGetVariable (
 461                  SmmVariableHeader->Name,
 462                  &SmmVariableHeader->Guid,
 463                  &SmmVariableHeader->Attributes,
 464                  &SmmVariableHeader->DataSize,
 465                  (UINT8 *)SmmVariableHeader->Name + SmmVariableHeader->NameSize
 466                  );
 467       break;
 468
 469     case SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME:
 470       GetNextVariableName = (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME *) SmmVariableFunctionHeader->Data;
 471       InfoSize = OFFSET_OF(SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name) + GetNextVariableName->NameSize;
 472
 473       //
 474       // SMRAM range check already covered before
 475       //
 476       if (InfoSize > *CommBufferSize - SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
 477         DEBUG ((EFI_D_ERROR, "Data size exceed communication buffer size limit!\n"));
 478         Status = EFI_ACCESS_DENIED;
 479         goto EXIT;
 480       }
 481
 482       Status = VariableServiceGetNextVariableName (
 483                  &GetNextVariableName->NameSize,
 484                  GetNextVariableName->Name,
 485                  &GetNextVariableName->Guid
 486                  );
 487       break;
 488
 489     case SMM_VARIABLE_FUNCTION_SET_VARIABLE:
 490       SmmVariableHeader = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *) SmmVariableFunctionHeader->Data;
 491       Status = VariableServiceSetVariable (
 492                  SmmVariableHeader->Name,
 493                  &SmmVariableHeader->Guid,
 494                  SmmVariableHeader->Attributes,
 495                  SmmVariableHeader->DataSize,
 496                  (UINT8 *)SmmVariableHeader->Name + SmmVariableHeader->NameSize
 497                  );
 498       break;
 499
 500     case SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO:
 501       QueryVariableInfo = (SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO *) SmmVariableFunctionHeader->Data;
 502       InfoSize = sizeof(SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO);
 503
 504       //
 505       // SMRAM range check already covered before
 506       //
 507       if (InfoSize > *CommBufferSize - SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
 508         DEBUG ((EFI_D_ERROR, "Data size exceed communication buffer size limit!\n"));
 509         Status = EFI_ACCESS_DENIED;
 510         goto EXIT;
 511       }
 512
 513       Status = VariableServiceQueryVariableInfo (
 514                  QueryVariableInfo->Attributes,
 515                  &QueryVariableInfo->MaximumVariableStorageSize,
 516                  &QueryVariableInfo->RemainingVariableStorageSize,
 517                  &QueryVariableInfo->MaximumVariableSize
 518                  );
 519       break;
 520
 521     case SMM_VARIABLE_FUNCTION_READY_TO_BOOT:
 522       if (AtRuntime()) {
 523         Status = EFI_UNSUPPORTED;
 524         break;
 525       }
 526       ReclaimForOS ();
 527       Status = EFI_SUCCESS;
 528       break;
 529
 530     case SMM_VARIABLE_FUNCTION_EXIT_BOOT_SERVICE:
 531       mAtRuntime = TRUE;
 532       Status = EFI_SUCCESS;
 533       break;
 534
 535     case SMM_VARIABLE_FUNCTION_GET_STATISTICS:
 536       VariableInfo = (VARIABLE_INFO_ENTRY *) SmmVariableFunctionHeader->Data;
 537       InfoSize = *CommBufferSize - SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;
 538
 539       //
 540       // Do not need to check SmmVariableFunctionHeader->Data in SMRAM here.
 541       // It is covered by previous CommBuffer check
 542       //
 543
 544       if (InternalIsAddressInSmram ((EFI_PHYSICAL_ADDRESS)(UINTN)CommBufferSize, sizeof(UINTN))) {
 545         DEBUG ((EFI_D_ERROR, "SMM communication buffer size is in SMRAM!\n"));
 546         Status = EFI_ACCESS_DENIED;
 547         goto EXIT;
 548       }
 549
 550       Status = SmmVariableGetStatistics (VariableInfo, &InfoSize);
 551       *CommBufferSize = InfoSize + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;
 552       break;
 553
 554     default:
 555       Status = EFI_UNSUPPORTED;
 556   }
 557
 558 EXIT:
 559
 560   SmmVariableFunctionHeader->ReturnStatus = Status;
 561   return EFI_SUCCESS;
 562 }
 563
 564
 565 /**
 566   SMM Fault Tolerant Write protocol notification event handler.
 567
 568   Non-Volatile variable write may needs FTW protocol to reclaim when
 569   writting variable.
 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   SmmEventCallback runs successfully
 576   @retval EFI_NOT_FOUND The Fvb protocol for variable is not found.
 577
 578  **/
 579 EFI_STATUS
 580 EFIAPI
 581 SmmFtwNotificationEvent (
 582   IN CONST EFI_GUID                       *Protocol,
 583   IN VOID                                 *Interface,
 584   IN EFI_HANDLE                           Handle
 585   )
 586 {
 587   EFI_STATUS                              Status;
 588   EFI_SMM_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *FvbProtocol;
 589   EFI_SMM_FAULT_TOLERANT_WRITE_PROTOCOL   *FtwProtocol;
 590   EFI_PHYSICAL_ADDRESS                    NvStorageVariableBase;
 591
 592   if (mVariableModuleGlobal->FvbInstance != NULL) {
 593     return EFI_SUCCESS;
 594   }
 595
 596   //
 597   // Ensure SMM FTW protocol is installed.
 598   //
 599   Status = GetFtwProtocol ((VOID **)&FtwProtocol);
 600   if (EFI_ERROR (Status)) {
 601     return Status;
 602   }
 603
 604   //
 605   // Find the proper FVB protocol for variable.
 606   //
 607   NvStorageVariableBase = (EFI_PHYSICAL_ADDRESS) PcdGet64 (PcdFlashNvStorageVariableBase64);
 608   if (NvStorageVariableBase == 0) {
 609     NvStorageVariableBase = (EFI_PHYSICAL_ADDRESS) PcdGet32 (PcdFlashNvStorageVariableBase);
 610   }
 611   Status = GetFvbInfoByAddress (NvStorageVariableBase, NULL, &FvbProtocol);
 612   if (EFI_ERROR (Status)) {
 613     return EFI_NOT_FOUND;
 614   }
 615
 616   mVariableModuleGlobal->FvbInstance = FvbProtocol;
 617
 618   Status = VariableWriteServiceInitialize ();
 619   ASSERT_EFI_ERROR (Status);
 620
 621   //
 622   // Notify the variable wrapper driver the variable write service is ready
 623   //
 624   Status = gBS->InstallProtocolInterface (
 625                   &mSmmVariableHandle,
 626                   &gSmmVariableWriteGuid,
 627                   EFI_NATIVE_INTERFACE,
 628                   NULL
 629                   );
 630   ASSERT_EFI_ERROR (Status);
 631
 632   return EFI_SUCCESS;
 633 }
 634
 635
 636 /**
 637   Variable Driver main entry point. The Variable driver places the 4 EFI
 638   runtime services in the EFI System Table and installs arch protocols
 639   for variable read and write services being available. It also registers
 640   a notification function for an EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event.
 641
 642   @param[in] ImageHandle    The firmware allocated handle for the EFI image.
 643   @param[in] SystemTable    A pointer to the EFI System Table.
 644
 645   @retval EFI_SUCCESS       Variable service successfully initialized.
 646
 647 **/
 648 EFI_STATUS
 649 EFIAPI
 650 VariableServiceInitialize (
 651   IN EFI_HANDLE                           ImageHandle,
 652   IN EFI_SYSTEM_TABLE                     *SystemTable
 653   )
 654 {
 655   EFI_STATUS                              Status;
 656   EFI_HANDLE                              VariableHandle;
 657   VOID                                    *SmmFtwRegistration;
 658   EFI_SMM_ACCESS2_PROTOCOL                *SmmAccess;
 659   UINTN                                   Size;
 660
 661   //
 662   // Variable initialize.
 663   //
 664   Status = VariableCommonInitialize ();
 665   ASSERT_EFI_ERROR (Status);
 666
 667   //
 668   // Install the Smm Variable Protocol on a new handle.
 669   //
 670   VariableHandle = NULL;
 671   Status = gSmst->SmmInstallProtocolInterface (
 672                     &VariableHandle,
 673                     &gEfiSmmVariableProtocolGuid,
 674                     EFI_NATIVE_INTERFACE,
 675                     &gSmmVariable
 676                     );
 677   ASSERT_EFI_ERROR (Status);
 678
 679   //
 680   // Get SMRAM information
 681   //
 682   Status = gBS->LocateProtocol (&gEfiSmmAccess2ProtocolGuid, NULL, (VOID **)&SmmAccess);
 683   ASSERT_EFI_ERROR (Status);
 684
 685   Size = 0;
 686   Status = SmmAccess->GetCapabilities (SmmAccess, &Size, NULL);
 687   ASSERT (Status == EFI_BUFFER_TOO_SMALL);
 688
 689   Status = gSmst->SmmAllocatePool (
 690                     EfiRuntimeServicesData,
 691                     Size,
 692                     (VOID **)&mSmramRanges
 693                     );
 694   ASSERT_EFI_ERROR (Status);
 695
 696   Status = SmmAccess->GetCapabilities (SmmAccess, &Size, mSmramRanges);
 697   ASSERT_EFI_ERROR (Status);
 698
 699   mSmramRangeCount = Size / sizeof (EFI_SMRAM_DESCRIPTOR);
 700
 701   ///
 702   /// Register SMM variable SMI handler
 703   ///
 704   VariableHandle = NULL;
 705   Status = gSmst->SmiHandlerRegister (SmmVariableHandler, &gEfiSmmVariableProtocolGuid, &VariableHandle);
 706   ASSERT_EFI_ERROR (Status);
 707
 708   //
 709   // Notify the variable wrapper driver the variable service is ready
 710   //
 711   Status = SystemTable->BootServices->InstallProtocolInterface (
 712                                         &mVariableHandle,
 713                                         &gEfiSmmVariableProtocolGuid,
 714                                         EFI_NATIVE_INTERFACE,
 715                                         &gSmmVariable
 716                                         );
 717   ASSERT_EFI_ERROR (Status);
 718
 719   //
 720   // Register FtwNotificationEvent () notify function.
 721   //
 722   Status = gSmst->SmmRegisterProtocolNotify (
 723                     &gEfiSmmFaultTolerantWriteProtocolGuid,
 724                     SmmFtwNotificationEvent,
 725                     &SmmFtwRegistration
 726                     );
 727   ASSERT_EFI_ERROR (Status);
 728
 729   SmmFtwNotificationEvent (NULL, NULL, NULL);
 730
 731   return EFI_SUCCESS;
 732 }
 733
 734