MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c

   1 /** @file
   2
   3   The sample implementation for SMM variable protocol. And this driver
   4   implements  an SMI handler to communicate with the DXE runtime driver
   5   to provide variable services.
   6
   7   Caution: This module requires additional review when modified.
   8   This driver will have external input - variable data and communicate buffer in SMM mode.
   9   This external input must be validated carefully to avoid security issue like
  10   buffer overflow, integer overflow.
  11
  12   SmmVariableHandler() will receive untrusted input and do basic validation.
  13
  14   Each sub function VariableServiceGetVariable(), VariableServiceGetNextVariableName(),
  15   VariableServiceSetVariable(), VariableServiceQueryVariableInfo(), ReclaimForOS(),
  16   SmmVariableGetStatistics() should also do validation based on its own knowledge.
  17
  18 Copyright (c) 2010 - 2012, Intel Corporation. All rights reserved.<BR>
  19 This program and the accompanying materials
  20 are licensed and made available under the terms and conditions of the BSD License
  21 which accompanies this distribution.  The full text of the license may be found at
  22 http://opensource.org/licenses/bsd-license.php
  23
  24 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  25 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  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/VariableFormat.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
 303 **/
 304 EFI_STATUS
 305 SmmVariableGetStatistics (
 306   IN OUT VARIABLE_INFO_ENTRY                           *InfoEntry,
 307   IN OUT UINTN                                         *InfoSize
 308   )
 309 {
 310   VARIABLE_INFO_ENTRY                                  *VariableInfo;
 311   UINTN                                                NameLength;
 312   UINTN                                                StatisticsInfoSize;
 313   CHAR16                                               *InfoName;
 314
 315   ASSERT (InfoEntry != NULL);
 316   VariableInfo = gVariableInfo;
 317   if (VariableInfo == NULL) {
 318     return EFI_UNSUPPORTED;
 319   }
 320
 321   StatisticsInfoSize = sizeof (VARIABLE_INFO_ENTRY) + StrSize (VariableInfo->Name);
 322   if (*InfoSize < StatisticsInfoSize) {
 323     *InfoSize = StatisticsInfoSize;
 324     return EFI_BUFFER_TOO_SMALL;
 325   }
 326   InfoName = (CHAR16 *)(InfoEntry + 1);
 327
 328   if (CompareGuid (&InfoEntry->VendorGuid, &mZeroGuid)) {
 329     //
 330     // Return the first variable info
 331     //
 332     CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY));
 333     CopyMem (InfoName, VariableInfo->Name, StrSize (VariableInfo->Name));
 334     *InfoSize = StatisticsInfoSize;
 335     return EFI_SUCCESS;
 336   }
 337
 338   //
 339   // Get the next variable info
 340   //
 341   while (VariableInfo != NULL) {
 342     if (CompareGuid (&VariableInfo->VendorGuid, &InfoEntry->VendorGuid)) {
 343       NameLength = StrSize (VariableInfo->Name);
 344       if (NameLength == StrSize (InfoName)) {
 345         if (CompareMem (VariableInfo->Name, InfoName, NameLength) == 0) {
 346           //
 347           // Find the match one
 348           //
 349           VariableInfo = VariableInfo->Next;
 350           break;
 351         }
 352       }
 353     }
 354     VariableInfo = VariableInfo->Next;
 355   };
 356
 357   if (VariableInfo == NULL) {
 358     *InfoSize = 0;
 359     return EFI_SUCCESS;
 360   }
 361
 362   //
 363   // Output the new variable info
 364   //
 365   StatisticsInfoSize = sizeof (VARIABLE_INFO_ENTRY) + StrSize (VariableInfo->Name);
 366   if (*InfoSize < StatisticsInfoSize) {
 367     *InfoSize = StatisticsInfoSize;
 368     return EFI_BUFFER_TOO_SMALL;
 369   }
 370
 371   CopyMem (InfoEntry, VariableInfo, sizeof (VARIABLE_INFO_ENTRY));
 372   CopyMem (InfoName, VariableInfo->Name, StrSize (VariableInfo->Name));
 373   *InfoSize = StatisticsInfoSize;
 374
 375   return EFI_SUCCESS;
 376 }
 377
 378
 379 /**
 380   Communication service SMI Handler entry.
 381
 382   This SMI handler provides services for the variable wrapper driver.
 383
 384   Caution: This function may receive untrusted input.
 385   This variable data and communicate buffer are external input, so this function will do basic validation.
 386   Each sub function VariableServiceGetVariable(), VariableServiceGetNextVariableName(),
 387   VariableServiceSetVariable(), VariableServiceQueryVariableInfo(), ReclaimForOS(),
 388   SmmVariableGetStatistics() should also do validation based on its own knowledge.
 389
 390   @param[in]     DispatchHandle  The unique handle assigned to this handler by SmiHandlerRegister().
 391   @param[in]     RegisterContext Points to an optional handler context which was specified when the
 392                                  handler was registered.
 393   @param[in, out] CommBuffer     A pointer to a collection of data in memory that will
 394                                  be conveyed from a non-SMM environment into an SMM environment.
 395   @param[in, out] CommBufferSize The size of the CommBuffer.
 396
 397   @retval EFI_SUCCESS                         The interrupt was handled and quiesced. No other handlers
 398                                               should still be called.
 399   @retval EFI_WARN_INTERRUPT_SOURCE_QUIESCED  The interrupt has been quiesced but other handlers should
 400                                               still be called.
 401   @retval EFI_WARN_INTERRUPT_SOURCE_PENDING   The interrupt is still pending and other handlers should still
 402                                               be called.
 403   @retval EFI_INTERRUPT_PENDING               The interrupt could not be quiesced.
 404 **/
 405 EFI_STATUS
 406 EFIAPI
 407 SmmVariableHandler (
 408   IN     EFI_HANDLE                                DispatchHandle,
 409   IN     CONST VOID                                *RegisterContext,
 410   IN OUT VOID                                      *CommBuffer,
 411   IN OUT UINTN                                     *CommBufferSize
 412   )
 413 {
 414   EFI_STATUS                                       Status;
 415   SMM_VARIABLE_COMMUNICATE_HEADER                  *SmmVariableFunctionHeader;
 416   SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE         *SmmVariableHeader;
 417   SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME  *GetNextVariableName;
 418   SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO     *QueryVariableInfo;
 419   VARIABLE_INFO_ENTRY                              *VariableInfo;
 420   UINTN                                            InfoSize;
 421
 422   //
 423   // If input is invalid, stop processing this SMI
 424   //
 425   if (CommBuffer == NULL || CommBufferSize == NULL) {
 426     return EFI_SUCCESS;
 427   }
 428
 429   if (*CommBufferSize < SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
 430     return EFI_SUCCESS;
 431   }
 432
 433   if (InternalIsAddressInSmram ((EFI_PHYSICAL_ADDRESS)(UINTN)CommBuffer, *CommBufferSize)) {
 434     DEBUG ((EFI_D_ERROR, "SMM communication buffer size is in SMRAM!\n"));
 435     return EFI_SUCCESS;
 436   }
 437
 438   SmmVariableFunctionHeader = (SMM_VARIABLE_COMMUNICATE_HEADER *)CommBuffer;
 439   switch (SmmVariableFunctionHeader->Function) {
 440     case SMM_VARIABLE_FUNCTION_GET_VARIABLE:
 441       SmmVariableHeader = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *) SmmVariableFunctionHeader->Data;
 442       InfoSize = OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)
 443                  + SmmVariableHeader->DataSize + SmmVariableHeader->NameSize;
 444
 445       //
 446       // SMRAM range check already covered before
 447       //
 448       if (InfoSize > *CommBufferSize - SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
 449         DEBUG ((EFI_D_ERROR, "Data size exceed communication buffer size limit!\n"));
 450         Status = EFI_ACCESS_DENIED;
 451         goto EXIT;
 452       }
 453
 454       Status = VariableServiceGetVariable (
 455                  SmmVariableHeader->Name,
 456                  &SmmVariableHeader->Guid,
 457                  &SmmVariableHeader->Attributes,
 458                  &SmmVariableHeader->DataSize,
 459                  (UINT8 *)SmmVariableHeader->Name + SmmVariableHeader->NameSize
 460                  );
 461       break;
 462
 463     case SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME:
 464       GetNextVariableName = (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME *) SmmVariableFunctionHeader->Data;
 465       InfoSize = OFFSET_OF(SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name) + GetNextVariableName->NameSize;
 466
 467       //
 468       // SMRAM range check already covered before
 469       //
 470       if (InfoSize > *CommBufferSize - SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
 471         DEBUG ((EFI_D_ERROR, "Data size exceed communication buffer size limit!\n"));
 472         Status = EFI_ACCESS_DENIED;
 473         goto EXIT;
 474       }
 475
 476       Status = VariableServiceGetNextVariableName (
 477                  &GetNextVariableName->NameSize,
 478                  GetNextVariableName->Name,
 479                  &GetNextVariableName->Guid
 480                  );
 481       break;
 482
 483     case SMM_VARIABLE_FUNCTION_SET_VARIABLE:
 484       SmmVariableHeader = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *) SmmVariableFunctionHeader->Data;
 485       InfoSize = OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)
 486                  + SmmVariableHeader->DataSize + SmmVariableHeader->NameSize;
 487
 488       //
 489       // SMRAM range check already covered before
 490       // Data buffer should not contain SMM range
 491       //
 492       if (InfoSize > *CommBufferSize - SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
 493         DEBUG ((EFI_D_ERROR, "Data size exceed communication buffer size limit!\n"));
 494         Status = EFI_ACCESS_DENIED;
 495         goto EXIT;
 496       }
 497
 498       Status = VariableServiceSetVariable (
 499                  SmmVariableHeader->Name,
 500                  &SmmVariableHeader->Guid,
 501                  SmmVariableHeader->Attributes,
 502                  SmmVariableHeader->DataSize,
 503                  (UINT8 *)SmmVariableHeader->Name + SmmVariableHeader->NameSize
 504                  );
 505       break;
 506
 507     case SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO:
 508       QueryVariableInfo = (SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO *) SmmVariableFunctionHeader->Data;
 509       InfoSize = sizeof(SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO);
 510
 511       //
 512       // SMRAM range check already covered before
 513       //
 514       if (InfoSize > *CommBufferSize - SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {
 515         DEBUG ((EFI_D_ERROR, "Data size exceed communication buffer size limit!\n"));
 516         Status = EFI_ACCESS_DENIED;
 517         goto EXIT;
 518       }
 519
 520       Status = VariableServiceQueryVariableInfo (
 521                  QueryVariableInfo->Attributes,
 522                  &QueryVariableInfo->MaximumVariableStorageSize,
 523                  &QueryVariableInfo->RemainingVariableStorageSize,
 524                  &QueryVariableInfo->MaximumVariableSize
 525                  );
 526       break;
 527
 528     case SMM_VARIABLE_FUNCTION_READY_TO_BOOT:
 529       if (AtRuntime()) {
 530         Status = EFI_UNSUPPORTED;
 531         break;
 532       }
 533       ReclaimForOS ();
 534       Status = EFI_SUCCESS;
 535       break;
 536
 537     case SMM_VARIABLE_FUNCTION_EXIT_BOOT_SERVICE:
 538       mAtRuntime = TRUE;
 539       Status = EFI_SUCCESS;
 540       break;
 541
 542     case SMM_VARIABLE_FUNCTION_GET_STATISTICS:
 543       VariableInfo = (VARIABLE_INFO_ENTRY *) SmmVariableFunctionHeader->Data;
 544       InfoSize = *CommBufferSize - SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;
 545
 546       //
 547       // Do not need to check SmmVariableFunctionHeader->Data in SMRAM here.
 548       // It is covered by previous CommBuffer check
 549       //
 550
 551       if (InternalIsAddressInSmram ((EFI_PHYSICAL_ADDRESS)(UINTN)CommBufferSize, sizeof(UINTN))) {
 552         DEBUG ((EFI_D_ERROR, "SMM communication buffer size is in SMRAM!\n"));
 553         Status = EFI_ACCESS_DENIED;
 554         goto EXIT;
 555       }
 556
 557       Status = SmmVariableGetStatistics (VariableInfo, &InfoSize);
 558       *CommBufferSize = InfoSize + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;
 559       break;
 560
 561     default:
 562       Status = EFI_UNSUPPORTED;
 563   }
 564
 565 EXIT:
 566
 567   SmmVariableFunctionHeader->ReturnStatus = Status;
 568
 569   return EFI_SUCCESS;
 570 }
 571
 572
 573 /**
 574   SMM Fault Tolerant Write protocol notification event handler.
 575
 576   Non-Volatile variable write may needs FTW protocol to reclaim when
 577   writting variable.
 578
 579   @param  Protocol   Points to the protocol's unique identifier
 580   @param  Interface  Points to the interface instance
 581   @param  Handle     The handle on which the interface was installed
 582
 583   @retval EFI_SUCCESS   SmmEventCallback runs successfully
 584   @retval EFI_NOT_FOUND The Fvb protocol for variable is not found.
 585
 586  **/
 587 EFI_STATUS
 588 EFIAPI
 589 SmmFtwNotificationEvent (
 590   IN CONST EFI_GUID                       *Protocol,
 591   IN VOID                                 *Interface,
 592   IN EFI_HANDLE                           Handle
 593   )
 594 {
 595   EFI_STATUS                              Status;
 596   EFI_SMM_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *FvbProtocol;
 597   EFI_SMM_FAULT_TOLERANT_WRITE_PROTOCOL   *FtwProtocol;
 598   EFI_PHYSICAL_ADDRESS                    NvStorageVariableBase;
 599
 600   if (mVariableModuleGlobal->FvbInstance != NULL) {
 601     return EFI_SUCCESS;
 602   }
 603
 604   //
 605   // Ensure SMM FTW protocol is installed.
 606   //
 607   Status = GetFtwProtocol ((VOID **)&FtwProtocol);
 608   if (EFI_ERROR (Status)) {
 609     return Status;
 610   }
 611
 612   //
 613   // Find the proper FVB protocol for variable.
 614   //
 615   NvStorageVariableBase = (EFI_PHYSICAL_ADDRESS) PcdGet64 (PcdFlashNvStorageVariableBase64);
 616   if (NvStorageVariableBase == 0) {
 617     NvStorageVariableBase = (EFI_PHYSICAL_ADDRESS) PcdGet32 (PcdFlashNvStorageVariableBase);
 618   }
 619   Status = GetFvbInfoByAddress (NvStorageVariableBase, NULL, &FvbProtocol);
 620   if (EFI_ERROR (Status)) {
 621     return EFI_NOT_FOUND;
 622   }
 623
 624   mVariableModuleGlobal->FvbInstance = FvbProtocol;
 625
 626   Status = VariableWriteServiceInitialize ();
 627   ASSERT_EFI_ERROR (Status);
 628
 629   //
 630   // Notify the variable wrapper driver the variable write service is ready
 631   //
 632   Status = gBS->InstallProtocolInterface (
 633                   &mSmmVariableHandle,
 634                   &gSmmVariableWriteGuid,
 635                   EFI_NATIVE_INTERFACE,
 636                   NULL
 637                   );
 638   ASSERT_EFI_ERROR (Status);
 639
 640   return EFI_SUCCESS;
 641 }
 642
 643
 644 /**
 645   Variable Driver main entry point. The Variable driver places the 4 EFI
 646   runtime services in the EFI System Table and installs arch protocols
 647   for variable read and write services being available. It also registers
 648   a notification function for an EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event.
 649
 650   @param[in] ImageHandle    The firmware allocated handle for the EFI image.
 651   @param[in] SystemTable    A pointer to the EFI System Table.
 652
 653   @retval EFI_SUCCESS       Variable service successfully initialized.
 654
 655 **/
 656 EFI_STATUS
 657 EFIAPI
 658 VariableServiceInitialize (
 659   IN EFI_HANDLE                           ImageHandle,
 660   IN EFI_SYSTEM_TABLE                     *SystemTable
 661   )
 662 {
 663   EFI_STATUS                              Status;
 664   EFI_HANDLE                              VariableHandle;
 665   VOID                                    *SmmFtwRegistration;
 666   EFI_SMM_ACCESS2_PROTOCOL                *SmmAccess;
 667   UINTN                                   Size;
 668
 669   //
 670   // Variable initialize.
 671   //
 672   Status = VariableCommonInitialize ();
 673   ASSERT_EFI_ERROR (Status);
 674
 675   //
 676   // Install the Smm Variable Protocol on a new handle.
 677   //
 678   VariableHandle = NULL;
 679   Status = gSmst->SmmInstallProtocolInterface (
 680                     &VariableHandle,
 681                     &gEfiSmmVariableProtocolGuid,
 682                     EFI_NATIVE_INTERFACE,
 683                     &gSmmVariable
 684                     );
 685   ASSERT_EFI_ERROR (Status);
 686
 687   //
 688   // Get SMRAM information
 689   //
 690   Status = gBS->LocateProtocol (&gEfiSmmAccess2ProtocolGuid, NULL, (VOID **)&SmmAccess);
 691   ASSERT_EFI_ERROR (Status);
 692
 693   Size = 0;
 694   Status = SmmAccess->GetCapabilities (SmmAccess, &Size, NULL);
 695   ASSERT (Status == EFI_BUFFER_TOO_SMALL);
 696
 697   Status = gSmst->SmmAllocatePool (
 698                     EfiRuntimeServicesData,
 699                     Size,
 700                     (VOID **)&mSmramRanges
 701                     );
 702   ASSERT_EFI_ERROR (Status);
 703
 704   Status = SmmAccess->GetCapabilities (SmmAccess, &Size, mSmramRanges);
 705   ASSERT_EFI_ERROR (Status);
 706
 707   mSmramRangeCount = Size / sizeof (EFI_SMRAM_DESCRIPTOR);
 708
 709   ///
 710   /// Register SMM variable SMI handler
 711   ///
 712   VariableHandle = NULL;
 713   Status = gSmst->SmiHandlerRegister (SmmVariableHandler, &gEfiSmmVariableProtocolGuid, &VariableHandle);
 714   ASSERT_EFI_ERROR (Status);
 715
 716   //
 717   // Notify the variable wrapper driver the variable service is ready
 718   //
 719   Status = SystemTable->BootServices->InstallProtocolInterface (
 720                                         &mVariableHandle,
 721                                         &gEfiSmmVariableProtocolGuid,
 722                                         EFI_NATIVE_INTERFACE,
 723                                         &gSmmVariable
 724                                         );
 725   ASSERT_EFI_ERROR (Status);
 726
 727   //
 728   // Register FtwNotificationEvent () notify function.
 729   //
 730   Status = gSmst->SmmRegisterProtocolNotify (
 731                     &gEfiSmmFaultTolerantWriteProtocolGuid,
 732                     SmmFtwNotificationEvent,
 733                     &SmmFtwRegistration
 734                     );
 735   ASSERT_EFI_ERROR (Status);
 736
 737   SmmFtwNotificationEvent (NULL, NULL, NULL);
 738
 739   return EFI_SUCCESS;
 740 }
 741
 742