summaryrefslogtreecommitdiff
path: root/IntelFrameworkModulePkg/Universal/Acpi/AcpiS3SaveDxe/AcpiS3Save.c
blob: 1bbd9c74d1fe7440062d99b315c181b81c6d6882 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
/** @file
  This is an implementation of the ACPI S3 Save protocol.  This is defined in
  S3 boot path specification 0.9.

Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>

This program and the accompanying materials
are licensed and made available under the terms and conditions
of the BSD License which accompanies this distribution.  The
full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#include <PiDxe.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiRuntimeServicesTableLib.h>
#include <Library/HobLib.h>
#include <Library/LockBoxLib.h>
#include <Library/PcdLib.h>
#include <Library/DebugLib.h>
#include <Guid/AcpiVariableCompatibility.h>
#include <Guid/AcpiS3Context.h>
#include <Guid/Acpi.h>
#include <Protocol/AcpiS3Save.h>
#include <IndustryStandard/Acpi.h>

#include "AcpiS3Save.h"

/**
  Hook point for AcpiVariableThunkPlatform for InstallAcpiS3Save.
**/
VOID
InstallAcpiS3SaveThunk (
  VOID
  );

/**
  Hook point for AcpiVariableThunkPlatform for S3Ready.

  @param AcpiS3Context   ACPI s3 context
**/
VOID
S3ReadyThunkPlatform (
  IN ACPI_S3_CONTEXT      *AcpiS3Context
  );

UINTN     mLegacyRegionSize;

EFI_ACPI_S3_SAVE_PROTOCOL mS3Save = {
  LegacyGetS3MemorySize,
  S3Ready,
};

EFI_GUID              mAcpiS3IdtrProfileGuid = {
  0xdea652b0, 0xd587, 0x4c54, 0xb5, 0xb4, 0xc6, 0x82, 0xe7, 0xa0, 0xaa, 0x3d
};

/**
  Allocate EfiACPIMemoryNVS below 4G memory address.

  This function allocates EfiACPIMemoryNVS below 4G memory address.

  @param  Size         Size of memory to allocate.
  
  @return Allocated address for output.

**/
VOID*
AllocateAcpiNvsMemoryBelow4G (
  IN   UINTN   Size
  )
{
  UINTN                 Pages;
  EFI_PHYSICAL_ADDRESS  Address;
  EFI_STATUS            Status;
  VOID*                 Buffer;

  Pages = EFI_SIZE_TO_PAGES (Size);
  Address = 0xffffffff;

  Status  = gBS->AllocatePages (
                   AllocateMaxAddress,
                   EfiACPIMemoryNVS,
                   Pages,
                   &Address
                   );
  ASSERT_EFI_ERROR (Status);

  Buffer = (VOID *) (UINTN) Address;
  ZeroMem (Buffer, Size);

  return Buffer;
}

/**
  To find Facs in Acpi tables.
 
  To find Firmware ACPI control strutcure in Acpi Tables since the S3 waking vector is stored 
  in the table.

  @param AcpiTableGuid   The guid used to find ACPI table in UEFI ConfigurationTable.
  
  @return  Facs table pointer.
**/
EFI_ACPI_2_0_FIRMWARE_ACPI_CONTROL_STRUCTURE  *
FindAcpiFacsTableByAcpiGuid (
  IN EFI_GUID  *AcpiTableGuid
  )
{
  EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER  *Rsdp;
  EFI_ACPI_DESCRIPTION_HEADER                   *Rsdt;
  EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE     *Fadt;
  EFI_ACPI_2_0_FIRMWARE_ACPI_CONTROL_STRUCTURE  *Facs;
  UINTN                                         Index;
  UINT32                                        Data32;
  Rsdp  = NULL;
  Rsdt  = NULL;
  Fadt  = NULL;
  //
  // found ACPI table RSD_PTR from system table
  //
  for (Index = 0; Index < gST->NumberOfTableEntries; Index++) {
    if (CompareGuid (&(gST->ConfigurationTable[Index].VendorGuid), AcpiTableGuid)) {
      //
      // A match was found.
      //
      Rsdp = gST->ConfigurationTable[Index].VendorTable;
      break;
    }
  }

  if (Rsdp == NULL) {
    return NULL;
  }

  Rsdt = (EFI_ACPI_DESCRIPTION_HEADER *)(UINTN) Rsdp->RsdtAddress;
  if (Rsdt == NULL || Rsdt->Signature != EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_TABLE_SIGNATURE) {
    return NULL;
  }

  for (Index = sizeof (EFI_ACPI_DESCRIPTION_HEADER); Index < Rsdt->Length; Index = Index + sizeof (UINT32)) {

    Data32  = *(UINT32 *) ((UINT8 *) Rsdt + Index);
    Fadt    = (EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE *) (UINT32 *) (UINTN) Data32;
    if (Fadt->Header.Signature == EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE_SIGNATURE) {
      break;
    }
  }

  if (Fadt == NULL || Fadt->Header.Signature != EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE_SIGNATURE) {
    return NULL;
  }

  Facs = (EFI_ACPI_2_0_FIRMWARE_ACPI_CONTROL_STRUCTURE *)(UINTN)Fadt->FirmwareCtrl;

  return Facs;
}

/**
  To find Facs in Acpi tables.
 
  To find Firmware ACPI control strutcure in Acpi Tables since the S3 waking vector is stored 
  in the table.
  
  @return  Facs table pointer.
**/
EFI_ACPI_2_0_FIRMWARE_ACPI_CONTROL_STRUCTURE  *
FindAcpiFacsTable (
  VOID
  )
{
  EFI_ACPI_2_0_FIRMWARE_ACPI_CONTROL_STRUCTURE *Facs;

  Facs = FindAcpiFacsTableByAcpiGuid (&gEfiAcpi20TableGuid);
  if (Facs != NULL) {
    return Facs;
  }

  return FindAcpiFacsTableByAcpiGuid (&gEfiAcpi10TableGuid);
}

/**
  Allocates and fills in the Page Directory and Page Table Entries to
  establish a 1:1 Virtual to Physical mapping.
  If BootScriptExector driver will run in 64-bit mode, this function will establish the 1:1 
  virtual to physical mapping page table.
  If BootScriptExector driver will not run in 64-bit mode, this function will do nothing. 
  
  @return  the 1:1 Virtual to Physical identity mapping page table base address. 

**/
EFI_PHYSICAL_ADDRESS
S3CreateIdentityMappingPageTables (
  VOID
  )
{  
  if (FeaturePcdGet (PcdDxeIplSwitchToLongMode)) {
    UINT32                                        RegEax;
    UINT32                                        RegEdx;
    UINT8                                         PhysicalAddressBits;
    EFI_PHYSICAL_ADDRESS                          PageAddress;
    UINTN                                         IndexOfPml4Entries;
    UINTN                                         IndexOfPdpEntries;
    UINTN                                         IndexOfPageDirectoryEntries;
    UINT32                                        NumberOfPml4EntriesNeeded;
    UINT32                                        NumberOfPdpEntriesNeeded;
    PAGE_MAP_AND_DIRECTORY_POINTER                *PageMapLevel4Entry;
    PAGE_MAP_AND_DIRECTORY_POINTER                *PageMap;
    PAGE_MAP_AND_DIRECTORY_POINTER                *PageDirectoryPointerEntry;
    PAGE_TABLE_ENTRY                              *PageDirectoryEntry;
    EFI_PHYSICAL_ADDRESS                          S3NvsPageTableAddress;
    UINTN                                         TotalPageTableSize;
    VOID                                          *Hob;
    BOOLEAN                                       Page1GSupport;
    PAGE_TABLE_1G_ENTRY                           *PageDirectory1GEntry;

    Page1GSupport = FALSE;
    AsmCpuid (0x80000000, &RegEax, NULL, NULL, NULL);
    if (RegEax >= 0x80000001) {
      AsmCpuid (0x80000001, NULL, NULL, NULL, &RegEdx);
      if ((RegEdx & BIT26) != 0) {
        Page1GSupport = TRUE;
      }
    }

    //
    // Get physical address bits supported.
    //
    Hob = GetFirstHob (EFI_HOB_TYPE_CPU);
    if (Hob != NULL) {
      PhysicalAddressBits = ((EFI_HOB_CPU *) Hob)->SizeOfMemorySpace;
    } else {
      AsmCpuid (0x80000000, &RegEax, NULL, NULL, NULL);
      if (RegEax >= 0x80000008) {
        AsmCpuid (0x80000008, &RegEax, NULL, NULL, NULL);
        PhysicalAddressBits = (UINT8) RegEax;
      } else {
        PhysicalAddressBits = 36;
      }
    }
    
    //
    // IA-32e paging translates 48-bit linear addresses to 52-bit physical addresses.
    //
    ASSERT (PhysicalAddressBits <= 52);
    if (PhysicalAddressBits > 48) {
      PhysicalAddressBits = 48;
    }

    //
    // Calculate the table entries needed.
    //
    if (PhysicalAddressBits <= 39 ) {
      NumberOfPml4EntriesNeeded = 1;
      NumberOfPdpEntriesNeeded = (UINT32)LShiftU64 (1, (PhysicalAddressBits - 30));
    } else {
      NumberOfPml4EntriesNeeded = (UINT32)LShiftU64 (1, (PhysicalAddressBits - 39));
      NumberOfPdpEntriesNeeded = 512;
    }

    //
    // We need calculate whole page size then allocate once, because S3 restore page table does not know each page in Nvs.
    //
    if (!Page1GSupport) {
      TotalPageTableSize = (UINTN)(1 + NumberOfPml4EntriesNeeded + NumberOfPml4EntriesNeeded * NumberOfPdpEntriesNeeded);
    } else {
      TotalPageTableSize = (UINTN)(1 + NumberOfPml4EntriesNeeded);
    }
    DEBUG ((EFI_D_ERROR, "TotalPageTableSize - %x pages\n", TotalPageTableSize));

    //
    // By architecture only one PageMapLevel4 exists - so lets allocate storgage for it.
    //
    S3NvsPageTableAddress = (EFI_PHYSICAL_ADDRESS)(UINTN)AllocateAcpiNvsMemoryBelow4G (EFI_PAGES_TO_SIZE(TotalPageTableSize));
    ASSERT (S3NvsPageTableAddress != 0);
    PageMap = (PAGE_MAP_AND_DIRECTORY_POINTER *)(UINTN)S3NvsPageTableAddress;
    S3NvsPageTableAddress += SIZE_4KB;

    PageMapLevel4Entry = PageMap;
    PageAddress        = 0;
    for (IndexOfPml4Entries = 0; IndexOfPml4Entries < NumberOfPml4EntriesNeeded; IndexOfPml4Entries++, PageMapLevel4Entry++) {
      //
      // Each PML4 entry points to a page of Page Directory Pointer entires.
      // So lets allocate space for them and fill them in in the IndexOfPdpEntries loop.
      //
      PageDirectoryPointerEntry = (PAGE_MAP_AND_DIRECTORY_POINTER *)(UINTN)S3NvsPageTableAddress;
      S3NvsPageTableAddress += SIZE_4KB;
      //
      // Make a PML4 Entry
      //
      PageMapLevel4Entry->Uint64 = (UINT64)(UINTN)PageDirectoryPointerEntry;
      PageMapLevel4Entry->Bits.ReadWrite = 1;
      PageMapLevel4Entry->Bits.Present = 1;
    
      if (Page1GSupport) {
        PageDirectory1GEntry = (PAGE_TABLE_1G_ENTRY *)(UINTN)S3NvsPageTableAddress;
        S3NvsPageTableAddress += SIZE_4KB;
    
        for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectory1GEntry++, PageAddress += SIZE_1GB) {
          //
          // Fill in the Page Directory entries
          //
          PageDirectory1GEntry->Uint64 = (UINT64)PageAddress;
          PageDirectory1GEntry->Bits.ReadWrite = 1;
          PageDirectory1GEntry->Bits.Present = 1;
          PageDirectory1GEntry->Bits.MustBe1 = 1;
        }
      } else {
        for (IndexOfPdpEntries = 0; IndexOfPdpEntries < NumberOfPdpEntriesNeeded; IndexOfPdpEntries++, PageDirectoryPointerEntry++) {
          //
          // Each Directory Pointer entries points to a page of Page Directory entires.
          // So allocate space for them and fill them in in the IndexOfPageDirectoryEntries loop.
          //       
          PageDirectoryEntry = (PAGE_TABLE_ENTRY *)(UINTN)S3NvsPageTableAddress;
          S3NvsPageTableAddress += SIZE_4KB;
      
          //
          // Fill in a Page Directory Pointer Entries
          //
          PageDirectoryPointerEntry->Uint64 = (UINT64)(UINTN)PageDirectoryEntry;
          PageDirectoryPointerEntry->Bits.ReadWrite = 1;
          PageDirectoryPointerEntry->Bits.Present = 1;
      
          for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PageAddress += SIZE_2MB) {
            //
            // Fill in the Page Directory entries
            //
            PageDirectoryEntry->Uint64 = (UINT64)PageAddress;
            PageDirectoryEntry->Bits.ReadWrite = 1;
            PageDirectoryEntry->Bits.Present = 1;
            PageDirectoryEntry->Bits.MustBe1 = 1;
          }
        }
      }
    }
    return (EFI_PHYSICAL_ADDRESS) (UINTN) PageMap;
  } else {
    //
    // If DXE is running 32-bit mode, no need to establish page table.
    //
    return  (EFI_PHYSICAL_ADDRESS) 0;  
  }
}

/**
  Gets the buffer of legacy memory below 1 MB 
  This function is to get the buffer in legacy memory below 1MB that is required during S3 resume.

  @param This           A pointer to the EFI_ACPI_S3_SAVE_PROTOCOL instance.
  @param Size           The returned size of legacy memory below 1 MB.

  @retval EFI_SUCCESS           Size is successfully returned.
  @retval EFI_INVALID_PARAMETER The pointer Size is NULL.

**/
EFI_STATUS
EFIAPI
LegacyGetS3MemorySize (
  IN  EFI_ACPI_S3_SAVE_PROTOCOL   *This,
  OUT UINTN                       *Size
  )
{
  if (Size == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  *Size = mLegacyRegionSize;
  return EFI_SUCCESS;
}

/**
  Prepares all information that is needed in the S3 resume boot path.
  
  Allocate the resources or prepare informations and save in ACPI variable set for S3 resume boot path  
  
  @param This                 A pointer to the EFI_ACPI_S3_SAVE_PROTOCOL instance.
  @param LegacyMemoryAddress  The base address of legacy memory.

  @retval EFI_NOT_FOUND         Some necessary information cannot be found.
  @retval EFI_SUCCESS           All information was saved successfully.
  @retval EFI_OUT_OF_RESOURCES  Resources were insufficient to save all the information.
  @retval EFI_INVALID_PARAMETER The memory range is not located below 1 MB.

**/
EFI_STATUS
EFIAPI
S3Ready (
  IN EFI_ACPI_S3_SAVE_PROTOCOL    *This,
  IN VOID                         *LegacyMemoryAddress
  )
{
  EFI_STATUS                                    Status;
  EFI_PHYSICAL_ADDRESS                          AcpiS3ContextBuffer;
  ACPI_S3_CONTEXT                               *AcpiS3Context;
  STATIC BOOLEAN                                AlreadyEntered;
  IA32_DESCRIPTOR                               *Idtr;
  IA32_IDT_GATE_DESCRIPTOR                      *IdtGate;

  DEBUG ((EFI_D_INFO, "S3Ready!\n"));

  //
  // Platform may invoke AcpiS3Save->S3Save() before ExitPmAuth, because we need save S3 information there, while BDS ReadyToBoot may invoke it again.
  // So if 2nd S3Save() is triggered later, we need ignore it.
  //
  if (AlreadyEntered) {
    return EFI_SUCCESS;
  }
  AlreadyEntered = TRUE;

  AcpiS3Context = AllocateAcpiNvsMemoryBelow4G (sizeof(*AcpiS3Context));
  ASSERT (AcpiS3Context != NULL);
  AcpiS3ContextBuffer = (EFI_PHYSICAL_ADDRESS)(UINTN)AcpiS3Context;

  //
  // Get ACPI Table because we will save its position to variable
  //
  AcpiS3Context->AcpiFacsTable = (EFI_PHYSICAL_ADDRESS)(UINTN)FindAcpiFacsTable ();
  ASSERT (AcpiS3Context->AcpiFacsTable != 0);

  IdtGate = AllocateAcpiNvsMemoryBelow4G (sizeof(IA32_IDT_GATE_DESCRIPTOR) * 0x100 + sizeof(IA32_DESCRIPTOR));
  Idtr = (IA32_DESCRIPTOR *)(IdtGate + 0x100);
  Idtr->Base  = (UINTN)IdtGate;
  Idtr->Limit = (UINT16)(sizeof(IA32_IDT_GATE_DESCRIPTOR) * 0x100 - 1);
  AcpiS3Context->IdtrProfile = (EFI_PHYSICAL_ADDRESS)(UINTN)Idtr;

  Status = SaveLockBox (
             &mAcpiS3IdtrProfileGuid,
             (VOID *)(UINTN)Idtr,
             (UINTN)sizeof(IA32_DESCRIPTOR)
             );
  ASSERT_EFI_ERROR (Status);

  Status = SetLockBoxAttributes (&mAcpiS3IdtrProfileGuid, LOCK_BOX_ATTRIBUTE_RESTORE_IN_PLACE);
  ASSERT_EFI_ERROR (Status);

  //
  // Allocate page table
  //
  AcpiS3Context->S3NvsPageTableAddress = S3CreateIdentityMappingPageTables ();

  //
  // Allocate stack
  //
  AcpiS3Context->BootScriptStackSize = PcdGet32 (PcdS3BootScriptStackSize);
  AcpiS3Context->BootScriptStackBase = (EFI_PHYSICAL_ADDRESS)(UINTN)AllocateAcpiNvsMemoryBelow4G (PcdGet32 (PcdS3BootScriptStackSize));
  ASSERT (AcpiS3Context->BootScriptStackBase != 0);

  //
  // Allocate a code buffer < 4G for S3 debug to load external code
  //
  AcpiS3Context->S3DebugBufferAddress = (EFI_PHYSICAL_ADDRESS)(UINTN)AllocateAcpiNvsMemoryBelow4G (EFI_PAGE_SIZE);

  DEBUG((EFI_D_INFO, "AcpiS3Context: AcpiFacsTable is 0x%8x\n", AcpiS3Context->AcpiFacsTable));
  DEBUG((EFI_D_INFO, "AcpiS3Context: IdtrProfile is 0x%8x\n", AcpiS3Context->IdtrProfile));
  DEBUG((EFI_D_INFO, "AcpiS3Context: S3NvsPageTableAddress is 0x%8x\n", AcpiS3Context->S3NvsPageTableAddress));
  DEBUG((EFI_D_INFO, "AcpiS3Context: S3DebugBufferAddress is 0x%8x\n", AcpiS3Context->S3DebugBufferAddress));

  Status = SaveLockBox (
             &gEfiAcpiVariableGuid,
             &AcpiS3ContextBuffer,
             sizeof(AcpiS3ContextBuffer)
             );
  ASSERT_EFI_ERROR (Status);

  Status = SaveLockBox (
             &gEfiAcpiS3ContextGuid,
             (VOID *)(UINTN)AcpiS3Context,
             (UINTN)sizeof(*AcpiS3Context)
             );
  ASSERT_EFI_ERROR (Status);

  Status = SetLockBoxAttributes (&gEfiAcpiS3ContextGuid, LOCK_BOX_ATTRIBUTE_RESTORE_IN_PLACE);
  ASSERT_EFI_ERROR (Status);

  if (FeaturePcdGet(PcdFrameworkCompatibilitySupport)) {
    S3ReadyThunkPlatform (AcpiS3Context);
  }

  return EFI_SUCCESS;
}

/**
  The Driver Entry Point.
  
  The function is the driver Entry point which will produce AcpiS3SaveProtocol.
  
  @param ImageHandle   A handle for the image that is initializing this driver
  @param SystemTable   A pointer to the EFI system table

  @retval EFI_SUCCESS:              Driver initialized successfully
  @retval EFI_LOAD_ERROR:           Failed to Initialize or has been loaded
  @retval EFI_OUT_OF_RESOURCES      Could not allocate needed resources

**/
EFI_STATUS
EFIAPI
InstallAcpiS3Save (
  IN EFI_HANDLE           ImageHandle,
  IN EFI_SYSTEM_TABLE     *SystemTable
  )
{
  EFI_STATUS        Status;

  if (!FeaturePcdGet(PcdPlatformCsmSupport)) {
    //
    // More memory for no CSM tip, because GDT need relocation
    //
    mLegacyRegionSize = 0x250;
  } else {
    mLegacyRegionSize = 0x100;
  }

  if (FeaturePcdGet(PcdFrameworkCompatibilitySupport)) {
    InstallAcpiS3SaveThunk ();
  }

  Status = gBS->InstallProtocolInterface (
                  &ImageHandle,
                  &gEfiAcpiS3SaveProtocolGuid,
                  EFI_NATIVE_INTERFACE,
                  &mS3Save
                  );
  ASSERT_EFI_ERROR (Status);
  return Status;
}