Re: [PATCH 3/3] FatPkg: Add GPT check in FatPei to support Capsule-on-Disk feature.

["Wu, Hao A" <hao.a.wu@intel.com>]

> -----Original Message-----
> From: Ni, Ray
> Sent: Thursday, January 17, 2019 11:50 AM
> To: Chen, Chen A; edk2-devel@lists.01.org; Wu, Hao A
> Cc: Zhang, Chao B
> Subject: RE: [PATCH 3/3] FatPkg: Add GPT check in FatPei to support Capsule-
> on-Disk feature.
> 
> Adding Wu Hao in the reviewer list.

Sorry for the delayed response.
I will try my best to give my comments as soon as possible.

Please help to ping if there is reply within the next two weeks.

Best Regards,
Hao Wu

> 
> > -----Original Message-----
> > From: Chen, Chen A <chen.a.chen@intel.com>
> > Sent: Thursday, January 17, 2019 10:03 AM
> > To: edk2-devel@lists.01.org
> > Cc: Chen, Chen A <chen.a.chen@intel.com>; Ni, Ray <ray.ni@intel.com>;
> > Zhang, Chao B <chao.b.zhang@intel.com>
> > Subject: [PATCH 3/3] FatPkg: Add GPT check in FatPei to support Capsule-
> on-
> > Disk feature.
> >
> > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1470
> > This feature is used for finding GPT partition, follow the following step to
> > check.
> > 1) Check Protective MBR.
> > 2) Check GPT primary/backup header.
> > 3) Check GPT primary/backup entry array.
> >
> > Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> > Cc: Zhang Chao B <chao.b.zhang@intel.com>
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Chen A Chen <chen.a.chen@intel.com>
> > ---
> >  FatPkg/FatPei/FatLitePeim.h |   1 +
> >  FatPkg/FatPei/FatPei.inf    |   3 +
> >  FatPkg/FatPei/Gpt.c         | 546
> > ++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 550 insertions(+)
> >  create mode 100644 FatPkg/FatPei/Gpt.c
> >
> > diff --git a/FatPkg/FatPei/FatLitePeim.h b/FatPkg/FatPei/FatLitePeim.h
> index
> > fbf887da5f..afb429c56e 100644
> > --- a/FatPkg/FatPei/FatLitePeim.h
> > +++ b/FatPkg/FatPei/FatLitePeim.h
> > @@ -27,6 +27,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF
> ANY
> > KIND, EITHER EXPRESS OR IMPLIED.
> >  #include <Library/BaseLib.h>
> >  #include <Library/PeimEntryPoint.h>
> >  #include <Library/BaseMemoryLib.h>
> > +#include <Library/MemoryAllocationLib.h>
> >  #include <Library/PcdLib.h>
> >  #include <Library/PeiServicesTablePointerLib.h>
> >  #include <Library/PeiServicesLib.h>
> > diff --git a/FatPkg/FatPei/FatPei.inf b/FatPkg/FatPei/FatPei.inf index
> > 829e87fe92..dd0869f7cd 100644
> > --- a/FatPkg/FatPei/FatPei.inf
> > +++ b/FatPkg/FatPei/FatPei.inf
> > @@ -31,6 +31,7 @@
> >
> >  [Sources]
> >    Mbr.c
> > +  Gpt.c
> >    Eltorito.c
> >    Part.c
> >    FatLiteApi.c
> > @@ -49,6 +50,7 @@
> >  [LibraryClasses]
> >    PcdLib
> >    BaseMemoryLib
> > +  MemoryAllocationLib
> >    PeimEntryPoint
> >    BaseLib
> >    DebugLib
> > @@ -61,6 +63,7 @@
> >    gRecoveryOnFatIdeDiskGuid                   ## SOMETIMES_CONSUMES   ##
> > UNDEFINED
> >    gRecoveryOnFatFloppyDiskGuid                ## SOMETIMES_CONSUMES   ##
> > UNDEFINED
> >    gRecoveryOnFatNvmeDiskGuid                  ## SOMETIMES_CONSUMES   ##
> > UNDEFINED
> > +  gEfiPartTypeUnusedGuid                      ## SOMETIMES_CONSUMES   ##
> > UNDEFINED
> >
> >
> >  [Ppis]
> > diff --git a/FatPkg/FatPei/Gpt.c b/FatPkg/FatPei/Gpt.c new file mode
> 100644
> > index 0000000000..d1f4c1c8b5
> > --- /dev/null
> > +++ b/FatPkg/FatPei/Gpt.c
> > @@ -0,0 +1,546 @@
> > +/** @file
> > +  Routines supporting partition discovery and
> > +  logical device reading
> > +
> > +Copyright (c) 2006 - 2018, 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 <IndustryStandard/Mbr.h>
> > +#include <Uefi/UefiGpt.h>
> > +#include <Library/BaseLib.h>
> > +#include "FatLitePeim.h"
> > +
> > +//
> > +// Assumption: 'a' and 'blocksize' are all UINT32 or UINT64.
> > +// If 'a' and 'blocksize' are not the same type, should use DivU64xU32 to
> > calculate.
> > +//
> > +#define EFI_SIZE_TO_BLOCKS(a, blocksize)  (((a) / (blocksize)) + (((a)
> > +% (blocksize)) ? 1 : 0))
> > +
> > +//
> > +// GPT Partition Entry Status
> > +//
> > +typedef struct {
> > +  BOOLEAN OutOfRange;
> > +  BOOLEAN Overlap;
> > +  BOOLEAN OsSpecific;
> > +} EFI_PARTITION_ENTRY_STATUS;
> > +
> > +/**
> > +  Check if the CRC field in the Partition table header is valid
> > +
> > +  @param[in]  BlockIo     Parent BlockIo interface
> > +  @param[in]  DiskIo      Disk Io Protocol.
> > +  @param[in]  PartHeader  Partition table header structure
> > +
> > +  @retval TRUE      the CRC is valid
> > +  @retval FALSE     the CRC is invalid
> > +
> > +**/
> > +BOOLEAN
> > +PartitionCheckGptHeaderCRC (
> > +  IN  EFI_PARTITION_TABLE_HEADER  *PartHeader
> > +  )
> > +{
> > +  UINT32      GptHdrCrc;
> > +  UINT32      Crc;
> > +
> > +  GptHdrCrc = PartHeader->Header.CRC32;
> > +
> > +  //
> > +  // Set CRC field to zero when doing calcuation  //
> > +  PartHeader->Header.CRC32 = 0;
> > +
> > +  Crc = CalculateCrc32 (PartHeader, PartHeader->Header.HeaderSize);
> > +
> > +  //
> > +  // Restore Header CRC
> > +  //
> > +  PartHeader->Header.CRC32 = GptHdrCrc;
> > +
> > +  return (GptHdrCrc == Crc);
> > +}
> > +
> > +
> > +/**
> > +  Check if the CRC field in the Partition table header is valid
> > +  for Partition entry array.
> > +
> > +  @param[in]  BlockIo     Parent BlockIo interface
> > +  @param[in]  DiskIo      Disk Io Protocol.
> > +  @param[in]  PartHeader  Partition table header structure
> > +
> > +  @retval TRUE      the CRC is valid
> > +  @retval FALSE     the CRC is invalid
> > +
> > +**/
> > +BOOLEAN
> > +PartitionCheckGptEntryArrayCRC (
> > +  IN  EFI_PARTITION_TABLE_HEADER *PartHeader,
> > +  IN  EFI_PARTITION_ENTRY        *PartEntry
> > +  )
> > +{
> > +  UINT32      Crc;
> > +  UINTN       Size;
> > +
> > +  Size = (UINTN)MultU64x32(PartHeader->NumberOfPartitionEntries,
> > + PartHeader->SizeOfPartitionEntry);
> > +  Crc  = CalculateCrc32 (PartEntry, Size);
> > +
> > +  return (BOOLEAN) (PartHeader->PartitionEntryArrayCRC32 == Crc); }
> > +
> > +/**
> > +  The function is used for valid GPT table. Both for Primary and Backup GPT
> > header.
> > +
> > +  @param[in]  PrivateData       The global memory map
> > +  @param[in]  ParentBlockDevNo  The parent block device
> > +  @param[in]  IsPrimaryHeader   Indicate to which header will be checked.
> > +  @param[in]  PartHdr           Stores the partition table that is read
> > +
> > +  @retval TRUE      The partition table is valid
> > +  @retval FALSE     The partition table is not valid
> > +
> > +**/
> > +BOOLEAN
> > +PartitionCheckGptHeader (
> > +  IN  PEI_FAT_PRIVATE_DATA        *PrivateData,
> > +  IN  UINTN                       ParentBlockDevNo,
> > +  IN  BOOLEAN                     IsPrimaryHeader,
> > +  IN  EFI_PARTITION_TABLE_HEADER  *PartHdr
> > +  )
> > +{
> > +  PEI_FAT_BLOCK_DEVICE            *ParentBlockDev;
> > +  EFI_PEI_LBA                     Lba;
> > +  EFI_PEI_LBA                     AlternateLba;
> > +  EFI_PEI_LBA                     EntryArrayLastLba;
> > +
> > +  UINT64                          PartitionEntryArraySize;
> > +  UINT64                          PartitionEntryBlockNumb;
> > +  UINT32                          EntryArraySizeRemainder;
> > +
> > +  ParentBlockDev = &(PrivateData->BlockDevice[ParentBlockDevNo]);
> > +
> > +  if (IsPrimaryHeader) {
> > +    Lba          = PRIMARY_PART_HEADER_LBA;
> > +    AlternateLba = ParentBlockDev->LastBlock;  } else {
> > +    Lba          = ParentBlockDev->LastBlock;
> > +    AlternateLba = PRIMARY_PART_HEADER_LBA;  }
> > +
> > +  if ( (PartHdr->Header.Signature != EFI_PTAB_HEADER_ID) ||
> > +       (PartHdr->Header.Revision != 0x00010000) ||
> > +       (PartHdr->Header.HeaderSize < 92) ||
> > +       (PartHdr->Header.HeaderSize > ParentBlockDev->BlockSize) ||
> > +       (!PartitionCheckGptHeaderCRC (PartHdr)) ||
> > +       (PartHdr->Header.Reserved != 0)
> > +     ) {
> > +    DEBUG ((DEBUG_ERROR, "Invalid efi partition table header\n"));
> > +    return FALSE;
> > +  }
> > +
> > +  //
> > +  // |    Block0    |    Block1    |Block2 ~ FirstUsableLBA -
> > 1|FirstUsableLBA, ... ,LastUsableLBA|LastUsableLBA+1 ~ LastBlock-1|
> > LastBlock  |
> > +  // |Protective MBR|Primary Header|Entry Array(At Least 16384)|
> > Partition            | Entry Array(At Least 16384) |BackUp Header|
> > +  //
> > +  // 1. Protective MBR is fixed at Block 0.
> > +  // 2. Primary Header is fixed at Block 1.
> > +  // 3. Backup Header is fixed at LastBlock.
> > +  // 4. Must be remain 128*128 bytes for primary entry array.
> > +  // 5. Must be remain 128*128 bytes for backup entry array.
> > +  // 6. SizeOfPartitionEntry must be equals to 128 * 2^n.
> > +  //
> > +  if ( (PartHdr->MyLBA != Lba) ||
> > +       (PartHdr->AlternateLBA != AlternateLba) ||
> > +       (PartHdr->FirstUsableLBA < 2 + EFI_SIZE_TO_BLOCKS
> > (GPT_PART_ENTRY_MIN_SIZE, ParentBlockDev->BlockSize)) ||
> > +       (PartHdr->LastUsableLBA  > ParentBlockDev->LastBlock - 1 -
> > EFI_SIZE_TO_BLOCKS (GPT_PART_ENTRY_MIN_SIZE, ParentBlockDev-
> > >BlockSize)) ||
> > +       (PartHdr->FirstUsableLBA > PartHdr->LastUsableLBA) ||
> > +       (PartHdr->PartitionEntryLBA < 2) ||
> > +       (PartHdr->PartitionEntryLBA > ParentBlockDev->LastBlock - 1) ||
> > +       (PartHdr->PartitionEntryLBA >= PartHdr->FirstUsableLBA && PartHdr-
> > >PartitionEntryLBA <= PartHdr->LastUsableLBA) ||
> > +       (PartHdr->SizeOfPartitionEntry%128 != 0) ||
> > +       (PartHdr->SizeOfPartitionEntry != sizeof (EFI_PARTITION_ENTRY))
> > +     ) {
> > +    DEBUG ((DEBUG_ERROR, "Invalid efi partition table header\n"));
> > +    return FALSE;
> > +  }
> > +
> > +  PartitionEntryArraySize = MultU64x32
> > + (PartHdr->NumberOfPartitionEntries, PartHdr->SizeOfPartitionEntry);
> > + EntryArraySizeRemainder = 0;  PartitionEntryBlockNumb =
> > + DivU64x32Remainder (PartitionEntryArraySize, ParentBlockDev-
> >BlockSize,
> > &EntryArraySizeRemainder);  if (EntryArraySizeRemainder != 0) {
> > +    PartitionEntryBlockNumb++;
> > +  }
> > +
> > +  if (IsPrimaryHeader) {
> > +    EntryArrayLastLba = PartHdr->FirstUsableLBA;  } else {
> > +    EntryArrayLastLba = ParentBlockDev->LastBlock;  }
> > +
> > +  //
> > +  // Make sure partition entry array not overlaps with partition area or the
> > LastBlock.
> > +  //
> > +  if (PartHdr->PartitionEntryLBA + PartitionEntryBlockNumb >
> > EntryArrayLastLba) {
> > +    DEBUG ((DEBUG_ERROR, "GPT Partition Entry Array Error!\n"));
> > +    DEBUG ((DEBUG_ERROR, "PartitionEntryArraySize = %lu.\n",
> > PartitionEntryArraySize));
> > +    DEBUG ((DEBUG_ERROR, "PartitionEntryLBA = %lu.\n", PartHdr-
> > >PartitionEntryLBA));
> > +    DEBUG ((DEBUG_ERROR, "PartitionEntryBlockNumb = %lu.\n",
> > PartitionEntryBlockNumb));
> > +    DEBUG ((DEBUG_ERROR, "EntryArrayLastLba = %lu.\n",
> > EntryArrayLastLba));
> > +    return FALSE;
> > +  }
> > +
> > +  return TRUE;
> > +}
> > +
> > +/**
> > +  This function is used to verify each partition in block device.
> > +
> > +  @param[in]  PrivateData       The global memory map
> > +  @param[in]  ParentBlockDevNo  The parent block device
> > +  @param[in]  PartHdr           Stores the partition table that is read
> > +
> > +  @retval TRUE      The partition is valid
> > +  @retval FALSE     The partition is not valid
> > +
> > +**/
> > +
> > +BOOLEAN
> > +PartitionCheckGptEntryArray (
> > +  IN  PEI_FAT_PRIVATE_DATA        *PrivateData,
> > +  IN  UINTN                       ParentBlockDevNo,
> > +  IN  EFI_PARTITION_TABLE_HEADER  *PartHdr
> > +  )
> > +{
> > +  EFI_STATUS                      Status;
> > +  PEI_FAT_BLOCK_DEVICE            *ParentBlockDev;
> > +  PEI_FAT_BLOCK_DEVICE            *BlockDevPtr;
> > +
> > +  UINT64                          PartitionEntryArraySize;
> > +  UINT64                          PartitionEntryBlockNumb;
> > +  UINT32                          EntryArraySizeRemainder;
> > +
> > +  EFI_PARTITION_ENTRY             *PartitionEntryBuffer;
> > +  EFI_PARTITION_ENTRY_STATUS      *PartitionEntryStatus;
> > +
> > +  BOOLEAN                         Found;
> > +  EFI_LBA                         StartingLBA;
> > +  EFI_LBA                         EndingLBA;
> > +  UINTN                           Index;
> > +  UINTN                           Index1;
> > +  UINTN                           Index2;
> > +  EFI_PARTITION_ENTRY             *Entry;
> > +
> > +  ParentBlockDev  = &(PrivateData->BlockDevice[ParentBlockDevNo]);
> > +  Found           = FALSE;
> > +
> > +  PartitionEntryArraySize = MultU64x32
> > + (PartHdr->NumberOfPartitionEntries, PartHdr->SizeOfPartitionEntry);
> > + EntryArraySizeRemainder = 0;  PartitionEntryBlockNumb =
> > + DivU64x32Remainder (PartitionEntryArraySize, ParentBlockDev-
> >BlockSize,
> > &EntryArraySizeRemainder);  if (EntryArraySizeRemainder != 0) {
> > +    PartitionEntryBlockNumb++;
> > +  }
> > +  PartitionEntryArraySize = MultU64x32 (PartitionEntryBlockNumb,
> > + ParentBlockDev->BlockSize);
> > +
> > +  PartitionEntryBuffer = (EFI_PARTITION_ENTRY *) AllocatePages
> > + (EFI_SIZE_TO_PAGES ((UINTN)PartitionEntryArraySize));
> > +  if (PartitionEntryBuffer == NULL) {
> > +    DEBUG ((DEBUG_ERROR, "Allocate memory error!\n"));
> > +    goto EXIT;
> > +  }
> > +
> > +  PartitionEntryStatus = (EFI_PARTITION_ENTRY_STATUS *) AllocatePages
> > + (EFI_SIZE_TO_PAGES (PartHdr->NumberOfPartitionEntries * sizeof
> > (EFI_PARTITION_ENTRY_STATUS)));  if (PartitionEntryStatus == NULL) {
> > +    DEBUG ((DEBUG_ERROR, "Allocate memory error!\n"));
> > +    goto EXIT;
> > +  }
> > +  ZeroMem (PartitionEntryStatus, PartHdr->NumberOfPartitionEntries *
> > + sizeof (EFI_PARTITION_ENTRY_STATUS));
> > +
> > +  Status = FatReadBlock (
> > +             PrivateData,
> > +             ParentBlockDevNo,
> > +             PartHdr->PartitionEntryLBA,
> > +             (UINTN)PartitionEntryArraySize,
> > +             PartitionEntryBuffer
> > +             );
> > +  if (EFI_ERROR (Status)) {
> > +    DEBUG ((DEBUG_ERROR, "Read partition entry array error!\n"));
> > +    goto EXIT;
> > +  }
> > +
> > +  if (!PartitionCheckGptEntryArrayCRC (PartHdr, PartitionEntryBuffer)) {
> > +    DEBUG ((EFI_D_ERROR, "Partition entries CRC check fail\n"));
> > +    goto EXIT;
> > +  }
> > +
> > +  for (Index1 = 0; Index1 < PartHdr->NumberOfPartitionEntries; Index1++)
> {
> > +    Entry = (EFI_PARTITION_ENTRY *) ((UINT8 *) PartitionEntryBuffer +
> > Index1 * PartHdr->SizeOfPartitionEntry);
> > +    if (CompareGuid (&Entry->PartitionTypeGUID,
> > &gEfiPartTypeUnusedGuid)) {
> > +      continue;
> > +    }
> > +
> > +    StartingLBA = Entry->StartingLBA;
> > +    EndingLBA   = Entry->EndingLBA;
> > +    if (StartingLBA > EndingLBA ||
> > +        StartingLBA < PartHdr->FirstUsableLBA ||
> > +        StartingLBA > PartHdr->LastUsableLBA ||
> > +        EndingLBA < PartHdr->FirstUsableLBA ||
> > +        EndingLBA > PartHdr->LastUsableLBA
> > +        ) {
> > +      PartitionEntryStatus[Index1].OutOfRange = TRUE;
> > +      continue;
> > +    }
> > +
> > +    if ((Entry->Attributes & BIT1) != 0) {
> > +      //
> > +      // If Bit 1 is set, this indicate that this is an OS specific GUID partition.
> > +      //
> > +      PartitionEntryStatus[Index1].OsSpecific = TRUE;
> > +    }
> > +
> > +    for (Index2 = Index1 + 1; Index2 < PartHdr->NumberOfPartitionEntries;
> > Index2++) {
> > +      Entry = (EFI_PARTITION_ENTRY *) ((UINT8 *) PartitionEntryBuffer +
> > Index2 * PartHdr->SizeOfPartitionEntry);
> > +      if (CompareGuid (&Entry->PartitionTypeGUID,
> > &gEfiPartTypeUnusedGuid)) {
> > +        continue;
> > +      }
> > +
> > +      if (Entry->EndingLBA >= StartingLBA && Entry->StartingLBA <=
> EndingLBA)
> > {
> > +        //
> > +        // This region overlaps with the Index1'th region
> > +        //
> > +        PartitionEntryStatus[Index1].Overlap  = TRUE;
> > +        PartitionEntryStatus[Index2].Overlap  = TRUE;
> > +        continue;
> > +      }
> > +    }
> > +  }
> > +
> > +  for (Index = 0; Index < PartHdr->NumberOfPartitionEntries; Index++) {
> > +    if (CompareGuid (&PartitionEntryBuffer[Index].PartitionTypeGUID,
> > &gEfiPartTypeUnusedGuid)||
> > +        PartitionEntryStatus[Index].OutOfRange ||
> > +        PartitionEntryStatus[Index].Overlap ||
> > +        PartitionEntryStatus[Index].OsSpecific) {
> > +      //
> > +      // Don't use null EFI Partition Entries, Invalid Partition Entries or OS
> > specific
> > +      // partition Entries
> > +      //
> > +      continue;
> > +    }
> > +
> > +    if (PrivateData->BlockDeviceCount >= PEI_FAT_MAX_BLOCK_DEVICE) {
> > +      break;
> > +    }
> > +
> > +    Found                         = TRUE;
> > +    BlockDevPtr                   = &(PrivateData->BlockDevice[PrivateData-
> > >BlockDeviceCount]);
> > +
> > +    BlockDevPtr->BlockSize        = ParentBlockDev->BlockSize;
> > +    BlockDevPtr->LastBlock        = PartitionEntryBuffer[Index].EndingLBA;
> > +    BlockDevPtr->IoAlign          = ParentBlockDev->IoAlign;
> > +    BlockDevPtr->Logical          = TRUE;
> > +    BlockDevPtr->PartitionChecked = FALSE;
> > +    BlockDevPtr->StartingPos      = MultU64x32 (
> > +                                      PartitionEntryBuffer[Index].StartingLBA,
> > +                                      ParentBlockDev->BlockSize
> > +                                      );
> > +    BlockDevPtr->ParentDevNo      = ParentBlockDevNo;
> > +
> > +    PrivateData->BlockDeviceCount++;
> > +
> > +    DEBUG ((DEBUG_INFO, "Find GPT Partition [0x%lx",
> > PartitionEntryBuffer[Index].StartingLBA, BlockDevPtr->LastBlock));
> > +    DEBUG ((DEBUG_INFO, ", 0x%lx]\n", BlockDevPtr->LastBlock));
> > +    DEBUG ((DEBUG_INFO, "         BlockSize %x\n",  BlockDevPtr-
> >BlockSize));
> > +  }
> > +
> > +EXIT:
> > +  if (PartitionEntryBuffer != NULL) {
> > +    FreePages (PartitionEntryBuffer, EFI_SIZE_TO_PAGES
> > +((UINTN)PartitionEntryArraySize));
> > +  }
> > +
> > +  if (PartitionEntryStatus != NULL) {
> > +    FreePages (PartitionEntryStatus, EFI_SIZE_TO_PAGES
> > + (PartHdr->NumberOfPartitionEntries * sizeof
> > + (EFI_PARTITION_ENTRY_STATUS)));  }
> > +
> > +  return Found;
> > +}
> > +
> > +/**
> > +  The function is used to check GPT structure, include GPT header and GPT
> > entry array.
> > +
> > +  1. Check GPT header.
> > +  2. Check partition entry array.
> > +  3. Check each partitions.
> > +
> > +  @param  PrivateData       The global memory map
> > +  @param  ParentBlockDevNo  The parent block device
> > +  @param  IsPrimary         Indicate primary or backup to be check
> > +
> > +  @retval TRUE              Primary or backup GPT structure is valid.
> > +  @retval FALSE             Both primary and backup are invalid.
> > +
> > +**/
> > +BOOLEAN
> > +PartitionCheckGptStructure (
> > +  IN  PEI_FAT_PRIVATE_DATA      *PrivateData,
> > +  IN  UINTN                     ParentBlockDevNo,
> > +  IN  BOOLEAN                   IsPrimary
> > +  )
> > +{
> > +  EFI_STATUS                    Status;
> > +  PEI_FAT_BLOCK_DEVICE          *ParentBlockDev;
> > +  EFI_PARTITION_TABLE_HEADER    *PartHdr;
> > +  EFI_PEI_LBA                   GptHeaderLBA;
> > +
> > +  ParentBlockDev  = &(PrivateData->BlockDevice[ParentBlockDevNo]);
> > +  PartHdr         = (EFI_PARTITION_TABLE_HEADER *) PrivateData-
> >BlockData;
> > +
> > +  if (IsPrimary) {
> > +    GptHeaderLBA = PRIMARY_PART_HEADER_LBA;  } else {
> > +    GptHeaderLBA = ParentBlockDev->LastBlock;  }
> > +
> > +  Status = FatReadBlock (
> > +             PrivateData,
> > +             ParentBlockDevNo,
> > +             GptHeaderLBA,
> > +             ParentBlockDev->BlockSize,
> > +             PartHdr
> > +             );
> > +  if (EFI_ERROR (Status)) {
> > +    return FALSE;
> > +  }
> > +
> > +  if (!PartitionCheckGptHeader (PrivateData, ParentBlockDevNo, IsPrimary,
> > PartHdr)) {
> > +    return FALSE;
> > +  }
> > +
> > +  if (!PartitionCheckGptEntryArray (PrivateData, ParentBlockDevNo,
> > PartHdr)) {
> > +    return FALSE;
> > +  }
> > +
> > +  return TRUE;
> > +}
> > +
> > +/**
> > +  This function is used to check protective MBR structure before checking
> > GPT.
> > +
> > +  @param  PrivateData       The global memory map
> > +  @param  ParentBlockDevNo  The parent block device
> > +
> > +  @retval TRUE              Valid protective MBR
> > +  @retval FALSE             Invalid MBR
> > +**/
> > +BOOLEAN
> > +PartitionCheckProtectiveMbr (
> > +  IN  PEI_FAT_PRIVATE_DATA    *PrivateData,
> > +  IN  UINTN                   ParentBlockDevNo
> > +  )
> > +{
> > +  EFI_STATUS                  Status;
> > +  MASTER_BOOT_RECORD          *ProtectiveMbr;
> > +  MBR_PARTITION_ENTRY         *MbrPartition;
> > +  PEI_FAT_BLOCK_DEVICE        *ParentBlockDev;
> > +  UINTN                       Index;
> > +
> > +  ProtectiveMbr   = (MASTER_BOOT_RECORD *) PrivateData->BlockData;
> > +  ParentBlockDev  = &(PrivateData->BlockDevice[ParentBlockDevNo]);
> > +
> > +  //
> > +  // Read Protective MBR
> > +  //
> > +  Status = FatReadBlock (
> > +             PrivateData,
> > +             ParentBlockDevNo,
> > +             0,
> > +             ParentBlockDev->BlockSize,
> > +             ProtectiveMbr
> > +             );
> > +  if (EFI_ERROR (Status)) {
> > +    DEBUG ((DEBUG_ERROR, "GPT Error When Read Protective Mbr From
> > Partition!\n"));
> > +    return FALSE;
> > +  }
> > +
> > +  if (ProtectiveMbr->Signature != MBR_SIGNATURE) {
> > +    DEBUG ((DEBUG_ERROR, "Protective Mbr Signature is invalid!\n"));
> > +    return FALSE;
> > +  }
> > +
> > +  //
> > +  // The partition define in UEFI Spec Table 17.
> > +  // Boot Code, Unique MBR Disk Signature, Unknown.
> > +  // These parst will not used by UEFI, so we skip to check them.
> > +  //
> > +  for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) {
> > +    MbrPartition = (MBR_PARTITION_ENTRY *)&ProtectiveMbr-
> > >Partition[Index];
> > +    if (MbrPartition->BootIndicator   == 0x00 &&
> > +        MbrPartition->StartingCHS[0]  == 0x00 &&
> > +        MbrPartition->StartingCHS[1]  == 0x02 &&
> > +        MbrPartition->StartingCHS[2]  == 0x00 &&
> > +        MbrPartition->OSType          == PMBR_GPT_PARTITION &&
> > +        MbrPartition->StartingLBA     == 0x1
> > +       ) {
> > +      return TRUE;
> > +    }
> > +  }
> > +
> > +  DEBUG ((DEBUG_ERROR, "Protective Mbr, All Partition Entry Are
> > +Empty!\n"));
> > +  return FALSE;
> > +}
> > +
> > +/**
> > +  This function is used for findg GPT partition on block device.
> > +  As follow UEFI spec We should check protecive MBR first and then
> > +  try to check both primary/backup GPT structures.
> > +
> > +  @param  PrivateData       The global memory map
> > +  @param  ParentBlockDevNo  The parent block device
> > +
> > +  @retval TRUE              New partitions are detected and logical block
> devices
> > +                            are  added to block device array
> > +  @retval FALSE             No New partitions are added;
> > +
> > +**/
> > +BOOLEAN
> > +FatFindGptPartitions (
> > +  IN  PEI_FAT_PRIVATE_DATA *PrivateData,
> > +  IN  UINTN                ParentBlockDevNo
> > +  )
> > +{
> > +  BOOLEAN                      Found;
> > +  PEI_FAT_BLOCK_DEVICE         *ParentBlockDev;
> > +
> > +  if (ParentBlockDevNo > PEI_FAT_MAX_BLOCK_DEVICE - 1) {
> > +    return FALSE;
> > +  }
> > +
> > +  ParentBlockDev  = &(PrivateData->BlockDevice[ParentBlockDevNo]);
> > +  if (ParentBlockDev->BlockSize > PEI_FAT_MAX_BLOCK_SIZE) {
> > +    DEBUG ((DEBUG_ERROR, "Device BlockSize %x exceed
> > FAT_MAX_BLOCK_SIZE\n", ParentBlockDev->BlockSize));
> > +    return FALSE;
> > +  }
> > +
> > +  if (!PartitionCheckProtectiveMbr (PrivateData, ParentBlockDevNo)) {
> > +    return FALSE;
> > +  }
> > +
> > +  Found = PartitionCheckGptStructure (PrivateData, ParentBlockDevNo,
> > + TRUE);  if (!Found) {
> > +    DEBUG ((DEBUG_ERROR, "Primary GPT Header Error, Try to Check
> Backup
> > GPT Header!\n"));
> > +    Found = PartitionCheckGptStructure (PrivateData, ParentBlockDevNo,
> > + FALSE);  }
> > +
> > +  if (Found) {
> > +    ParentBlockDev->PartitionChecked = TRUE;  }
> > +
> > +  return Found;
> > +}
> > --
> > 2.16.2.windows.1