summaryrefslogtreecommitdiff
path: root/EdkModulePkg/Universal/Variable/Pei/Variable.c
blob: a2ea1d6584bd2e9e3c943b19c61d62cb5b620703 (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
/*++

Copyright (c) 2006 - 2007 Intel Corporation. <BR>
All rights reserved. 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.
Module Name:

  Variable.c

Abstract:

  Framework PEIM to provide the Variable functionality

--*/

#include <Variable.h>

//
// Module globals
//
static EFI_PEI_READ_ONLY_VARIABLE_PPI mVariablePpi = {
  PeiGetVariable,
  PeiGetNextVariableName
};

static EFI_PEI_PPI_DESCRIPTOR     mPpiListVariable = {
  (EFI_PEI_PPI_DESCRIPTOR_PPI | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),
  &gEfiPeiReadOnlyVariablePpiGuid,
  &mVariablePpi
};

EFI_GUID mEfiVariableIndexTableGuid = EFI_VARIABLE_INDEX_TABLE_GUID;

EFI_STATUS
EFIAPI
PeimInitializeVariableServices (
  IN EFI_FFS_FILE_HEADER       *FfsHeader,
  IN EFI_PEI_SERVICES          **PeiServices
  )
/*++

Routine Description:

  Provide the functionality of the variable services.

Arguments:

  FfsHeadher  - The FFS file header
  PeiServices - General purpose services available to every PEIM.

Returns:

  Status -  EFI_SUCCESS if the interface could be successfully
            installed

--*/
{
  //
  // Publish the variable capability to other modules
  //
  return (**PeiServices).InstallPpi (PeiServices, &mPpiListVariable);

}

STATIC
VARIABLE_HEADER *
GetNextVariablePtr (
  IN VARIABLE_HEADER  *Variable
  )
/*++

Routine Description:

  This code checks if variable header is valid or not.

Arguments:
  Variable       Pointer to the Variable Header.

Returns:
  TRUE            Variable header is valid.
  FALSE           Variable header is not valid.

--*/
{
  return (VARIABLE_HEADER *) ((UINTN) GET_VARIABLE_DATA_PTR (Variable) + Variable->DataSize + GET_PAD_SIZE (Variable->DataSize));
}

STATIC
BOOLEAN
EFIAPI
IsValidVariableHeader (
  IN  VARIABLE_HEADER   *Variable
  )
/*++

Routine Description:

  This code checks if variable header is valid or not.

Arguments:
  Variable              Pointer to the Variable Header.

Returns:
  TRUE            Variable header is valid.
  FALSE           Variable header is not valid.

--*/
{
  if (Variable == NULL ||
      Variable->StartId != VARIABLE_DATA ||
      (sizeof (VARIABLE_HEADER) + Variable->DataSize + Variable->NameSize) > MAX_VARIABLE_SIZE
      ) {
    return FALSE;
  }

  return TRUE;
}

STATIC
VARIABLE_STORE_STATUS
EFIAPI
GetVariableStoreStatus (
  IN VARIABLE_STORE_HEADER *VarStoreHeader
  )
/*++

Routine Description:

  This code gets the pointer to the variable name.

Arguments:

  VarStoreHeader  Pointer to the Variable Store Header.

Returns:

  EfiRaw        Variable store is raw
  EfiValid      Variable store is valid
  EfiInvalid    Variable store is invalid

--*/
{
  if (VarStoreHeader->Signature == VARIABLE_STORE_SIGNATURE &&
      VarStoreHeader->Format == VARIABLE_STORE_FORMATTED &&
      VarStoreHeader->State == VARIABLE_STORE_HEALTHY
      ) {

    return EfiValid;
  }

  if (VarStoreHeader->Signature == 0xffffffff &&
      VarStoreHeader->Size == 0xffffffff &&
      VarStoreHeader->Format == 0xff &&
      VarStoreHeader->State == 0xff
      ) {

    return EfiRaw;
  } else {
    return EfiInvalid;
  }
}

STATIC
EFI_STATUS
CompareWithValidVariable (
  IN  VARIABLE_HEADER         *Variable,
  IN  CHAR16                  *VariableName,
  IN  EFI_GUID                *VendorGuid,
  OUT VARIABLE_POINTER_TRACK  *PtrTrack
  )
/*++

Routine Description:

  This function compares a variable with variable entries in database

Arguments:

  Variable       - Pointer to the variable in our database
  VariableName   - Name of the variable to compare to 'Variable'
  VendorGuid     - GUID of the variable to compare to 'Variable'
  PtrTrack       - Variable Track Pointer structure that contains
                   Variable Information.

Returns:

  EFI_SUCCESS    - Found match variable
  EFI_NOT_FOUND  - Variable not found

--*/
{
  if (VariableName[0] == 0) {
    PtrTrack->CurrPtr = Variable;
    return EFI_SUCCESS;
  } else {
    //
    // Don't use CompareGuid function here for performance reasons.
    // Instead we compare the GUID a UINT32 at a time and branch
    // on the first failed comparison.
    //
    if ((((INT32 *) VendorGuid)[0] == ((INT32 *) &Variable->VendorGuid)[0]) &&
        (((INT32 *) VendorGuid)[1] == ((INT32 *) &Variable->VendorGuid)[1]) &&
        (((INT32 *) VendorGuid)[2] == ((INT32 *) &Variable->VendorGuid)[2]) &&
        (((INT32 *) VendorGuid)[3] == ((INT32 *) &Variable->VendorGuid)[3])
        ) {
      if (!CompareMem (VariableName, GET_VARIABLE_NAME_PTR (Variable), Variable->NameSize)) {
        PtrTrack->CurrPtr = Variable;
        return EFI_SUCCESS;
      }
    }
  }

  return EFI_NOT_FOUND;
}

STATIC
EFI_STATUS
EFIAPI
FindVariable (
  IN EFI_PEI_SERVICES         **PeiServices,
  IN  CHAR16                  *VariableName,
  IN  EFI_GUID                *VendorGuid,
  OUT VARIABLE_POINTER_TRACK  *PtrTrack
  )
/*++

Routine Description:

  This code finds variable in storage blocks (Non-Volatile)

Arguments:

  PeiServices    - General purpose services available to every PEIM.
  VariableName   - Name of the variable to be found
  VendorGuid     - Vendor GUID to be found.
  PtrTrack       - Variable Track Pointer structure that contains
                   Variable Information.

Returns:

  EFI_SUCCESS      - Variable found successfully
  EFI_NOT_FOUND    - Variable not found
  EFI_INVALID_PARAMETER  - Invalid variable name

--*/
{
  EFI_HOB_GUID_TYPE       *GuidHob;
  VARIABLE_STORE_HEADER   *VariableStoreHeader;
  VARIABLE_HEADER         *Variable;
  VARIABLE_HEADER         *MaxIndex;
  VARIABLE_INDEX_TABLE    *IndexTable;
  UINT32                  Count;
  UINT8                   *VariableBase;

  if (VariableName != 0 && VendorGuid == NULL) {
    return EFI_INVALID_PARAMETER;
  }
  //
  // No Variable Address equals zero, so 0 as initial value is safe.
  //
  MaxIndex = 0;

  GuidHob = GetFirstGuidHob (&mEfiVariableIndexTableGuid);
  if (GuidHob == NULL) {
    IndexTable = BuildGuidHob (&mEfiVariableIndexTableGuid, sizeof (VARIABLE_INDEX_TABLE));
    IndexTable->Length      = 0;
    IndexTable->StartPtr    = NULL;
    IndexTable->EndPtr      = NULL;
    IndexTable->GoneThrough = 0;
  } else {
    IndexTable = GET_GUID_HOB_DATA (GuidHob);
    for (Count = 0; Count < IndexTable->Length; Count++)
    {
      MaxIndex = GetVariableByIndex (IndexTable, Count);

      if (CompareWithValidVariable (MaxIndex, VariableName, VendorGuid, PtrTrack) == EFI_SUCCESS) {
        PtrTrack->StartPtr  = IndexTable->StartPtr;
        PtrTrack->EndPtr    = IndexTable->EndPtr;

        return EFI_SUCCESS;
      }
    }

    if (IndexTable->GoneThrough) {
      return EFI_NOT_FOUND;
    }
  }
  //
  // If not found in HOB, then let's start from the MaxIndex we've found.
  //
  if (MaxIndex != NULL) {
    Variable = GetNextVariablePtr (MaxIndex);
  } else {
    if (IndexTable->StartPtr || IndexTable->EndPtr) {
      Variable = IndexTable->StartPtr;
    } else {
      VariableBase = (UINT8 *) (UINTN) PcdGet32 (PcdFlashNvStorageVariableBase);
      VariableStoreHeader = (VARIABLE_STORE_HEADER *) (VariableBase + \
                            ((EFI_FIRMWARE_VOLUME_HEADER *) (VariableBase)) -> HeaderLength);

      if (GetVariableStoreStatus (VariableStoreHeader) != EfiValid) {
        return EFI_UNSUPPORTED;
      }

      if (~VariableStoreHeader->Size == 0) {
        return EFI_NOT_FOUND;
      }
      //
      // Find the variable by walk through non-volatile variable store
      //
      IndexTable->StartPtr  = (VARIABLE_HEADER *) (VariableStoreHeader + 1);
      IndexTable->EndPtr    = (VARIABLE_HEADER *) ((UINTN) VariableStoreHeader + VariableStoreHeader->Size);

      //
      // Start Pointers for the variable.
      // Actual Data Pointer where data can be written.
      //
      Variable = IndexTable->StartPtr;
    }
  }
  //
  // Find the variable by walk through non-volatile variable store
  //
  PtrTrack->StartPtr  = IndexTable->StartPtr;
  PtrTrack->EndPtr    = IndexTable->EndPtr;

  while (IsValidVariableHeader (Variable) && (Variable <= IndexTable->EndPtr)) {
    if (Variable->State == VAR_ADDED) {
      //
      // Record Variable in VariableIndex HOB
      //
      if (IndexTable->Length < VARIABLE_INDEX_TABLE_VOLUME)
      {
        VariableIndexTableUpdate (IndexTable, Variable);
      }

      if (CompareWithValidVariable (Variable, VariableName, VendorGuid, PtrTrack) == EFI_SUCCESS) {
        return EFI_SUCCESS;
      }
    }

    Variable = GetNextVariablePtr (Variable);
  }
  //
  // If gone through the VariableStore, that means we never find in Firmware any more.
  //
  if (IndexTable->Length < VARIABLE_INDEX_TABLE_VOLUME) {
    IndexTable->GoneThrough = 1;
  }

  PtrTrack->CurrPtr = NULL;

  return EFI_NOT_FOUND;
}

EFI_STATUS
EFIAPI
PeiGetVariable (
  IN EFI_PEI_SERVICES             **PeiServices,
  IN CHAR16                       *VariableName,
  IN EFI_GUID                     * VendorGuid,
  OUT UINT32                      *Attributes OPTIONAL,
  IN OUT UINTN                    *DataSize,
  OUT VOID                        *Data
  )
/*++

Routine Description:

  Provide the read variable functionality of the variable services.

Arguments:

  PeiServices - General purpose services available to every PEIM.

  VariableName     - The variable name

  VendorGuid       - The vendor's GUID

  Attributes       - Pointer to the attribute

  DataSize         - Size of data

  Data             - Pointer to data

Returns:

  EFI_SUCCESS           - The interface could be successfully installed

  EFI_NOT_FOUND         - The variable could not be discovered

  EFI_BUFFER_TOO_SMALL  - The caller buffer is not large enough

--*/
{
  VARIABLE_POINTER_TRACK  Variable;
  UINTN                   VarDataSize;
  EFI_STATUS              Status;

  if (VariableName == NULL || VendorGuid == NULL) {
    return EFI_INVALID_PARAMETER;
  }
  //
  // Find existing variable
  //
  Status = FindVariable (PeiServices, VariableName, VendorGuid, &Variable);

  if (Variable.CurrPtr == NULL || Status != EFI_SUCCESS) {
    return Status;
  }
  //
  // Get data size
  //
  VarDataSize = Variable.CurrPtr->DataSize;
  if (*DataSize >= VarDataSize) {
    (*PeiServices)->CopyMem (Data, GET_VARIABLE_DATA_PTR (Variable.CurrPtr), VarDataSize);

    if (Attributes != NULL) {
      *Attributes = Variable.CurrPtr->Attributes;
    }

    *DataSize = VarDataSize;
    return EFI_SUCCESS;
  } else {
    *DataSize = VarDataSize;
    return EFI_BUFFER_TOO_SMALL;
  }
}

EFI_STATUS
EFIAPI
PeiGetNextVariableName (
  IN EFI_PEI_SERVICES             **PeiServices,
  IN OUT UINTN                    *VariableNameSize,
  IN OUT CHAR16                   *VariableName,
  IN OUT EFI_GUID                 *VendorGuid
  )
/*++

Routine Description:

  Provide the get next variable functionality of the variable services.

Arguments:

  PeiServices        - General purpose services available to every PEIM.
  VariabvleNameSize  - The variable name's size.
  VariableName       - A pointer to the variable's name.
  VendorGuid         - A pointer to the EFI_GUID structure.

  VariableNameSize - Size of the variable name

  VariableName     - The variable name

  VendorGuid       - The vendor's GUID

Returns:

  EFI_SUCCESS - The interface could be successfully installed

  EFI_NOT_FOUND - The variable could not be discovered

--*/
{
  VARIABLE_POINTER_TRACK  Variable;
  UINTN                   VarNameSize;
  EFI_STATUS              Status;

  if (VariableName == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Status = FindVariable (PeiServices, VariableName, VendorGuid, &Variable);

  if (Variable.CurrPtr == NULL || Status != EFI_SUCCESS) {
    return Status;
  }

  if (VariableName[0] != 0) {
    //
    // If variable name is not NULL, get next variable
    //
    Variable.CurrPtr = GetNextVariablePtr (Variable.CurrPtr);
  }

  while (!(Variable.CurrPtr >= Variable.EndPtr || Variable.CurrPtr == NULL)) {
    if (IsValidVariableHeader (Variable.CurrPtr)) {
      if (Variable.CurrPtr->State == VAR_ADDED) {
        VarNameSize = (UINTN) Variable.CurrPtr->NameSize;
        if (VarNameSize <= *VariableNameSize) {
          (*PeiServices)->CopyMem (VariableName, GET_VARIABLE_NAME_PTR (Variable.CurrPtr), VarNameSize);

          (*PeiServices)->CopyMem (VendorGuid, &Variable.CurrPtr->VendorGuid, sizeof (EFI_GUID));

          Status = EFI_SUCCESS;
        } else {
          Status = EFI_BUFFER_TOO_SMALL;
        }

        *VariableNameSize = VarNameSize;
        return Status;
        //
        // Variable is found
        //
      } else {
        Variable.CurrPtr = GetNextVariablePtr (Variable.CurrPtr);
      }
    } else {
      break;
    }
  }

  return EFI_NOT_FOUND;
}