system76-edk2/MdePkg/Include/Uefi/UefiGpt.h

/** @file
  EFI Guid Partition Table Format Definition.

Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#ifndef __UEFI_GPT_H__
#define __UEFI_GPT_H__

///
/// The primary GUID Partition Table Header must be
/// located in LBA 1 (i.e., the second logical block).
///
#define PRIMARY_PART_HEADER_LBA 1
///
/// EFI Partition Table Signature: "EFI PART".
///
#define EFI_PTAB_HEADER_ID      SIGNATURE_64 ('E','F','I',' ','P','A','R','T')
///
/// Minimum bytes reserve for EFI entry array buffer.
///
#define EFI_GPT_PART_ENTRY_MIN_SIZE 16384

#pragma pack(1)

///
/// GPT Partition Table Header.
///
typedef struct {
  ///
  /// The table header for the GPT partition Table.
  /// This header contains EFI_PTAB_HEADER_ID.
  ///
  EFI_TABLE_HEADER  Header;
  ///
  /// The LBA that contains this data structure.
  ///
  EFI_LBA           MyLBA;
  ///
  /// LBA address of the alternate GUID Partition Table Header.
  ///
  EFI_LBA           AlternateLBA;
  ///
  /// The first usable logical block that may be used
  /// by a partition described by a GUID Partition Entry.
  ///
  EFI_LBA           FirstUsableLBA;
  ///
  /// The last usable logical block that may be used
  /// by a partition described by a GUID Partition Entry.
  ///
  EFI_LBA           LastUsableLBA;
  ///
  /// GUID that can be used to uniquely identify the disk.
  ///
  EFI_GUID          DiskGUID;
  ///
  /// The starting LBA of the GUID Partition Entry array.
  ///
  EFI_LBA           PartitionEntryLBA;
  ///
  /// The number of Partition Entries in the GUID Partition Entry array.
  ///
  UINT32            NumberOfPartitionEntries;
  ///
  /// The size, in bytes, of each the GUID Partition
  /// Entry structures in the GUID Partition Entry
  /// array. This field shall be set to a value of 128 x 2^n where n is
  /// an integer greater than or equal to zero (e.g., 128, 256, 512, etc.).
  ///
  UINT32            SizeOfPartitionEntry;
  ///
  /// The CRC32 of the GUID Partition Entry array.
  /// Starts at PartitionEntryLBA and is
  /// computed over a byte length of
  /// NumberOfPartitionEntries * SizeOfPartitionEntry.
  ///
  UINT32            PartitionEntryArrayCRC32;
} EFI_PARTITION_TABLE_HEADER;

///
/// GPT Partition Entry.
///
typedef struct {
  ///
  /// Unique ID that defines the purpose and type of this Partition. A value of
  /// zero defines that this partition entry is not being used.
  ///
  EFI_GUID  PartitionTypeGUID;
  ///
  /// GUID that is unique for every partition entry. Every partition ever
  /// created will have a unique GUID.
  /// This GUID must be assigned when the GUID Partition Entry is created.
  ///
  EFI_GUID  UniquePartitionGUID;
  ///
  /// Starting LBA of the partition defined by this entry
  ///
  EFI_LBA   StartingLBA;
  ///
  /// Ending LBA of the partition defined by this entry.
  ///
  EFI_LBA   EndingLBA;
  ///
  /// Attribute bits, all bits reserved by UEFI
  /// Bit 0:      If this bit is set, the partition is required for the platform to function. The owner/creator of the
  ///             partition indicates that deletion or modification of the contents can result in loss of platform
  ///             features or failure for the platform to boot or operate. The system cannot function normally if
  ///             this partition is removed, and it should be considered part of the hardware of the system.
  ///             Actions such as running diagnostics, system recovery, or even OS install or boot, could
  ///             potentially stop working if this partition is removed. Unless OS software or firmware
  ///             recognizes this partition, it should never be removed or modified as the UEFI firmware or
  ///             platform hardware may become non-functional.
  /// Bit 1:      If this bit is set, then firmware must not produce an EFI_BLOCK_IO_PROTOCOL device for
  ///             this partition. By not producing an EFI_BLOCK_IO_PROTOCOL partition, file system
  ///             mappings will not be created for this partition in UEFI.
  /// Bit 2:      This bit is set aside to let systems with traditional PC-AT BIOS firmware implementations
  ///             inform certain limited, special-purpose software running on these systems that a GPT
  ///             partition may be bootable. The UEFI boot manager must ignore this bit when selecting
  ///             a UEFI-compliant application, e.g., an OS loader.
  /// Bits 3-47:  Undefined and must be zero. Reserved for expansion by future versions of the UEFI
  ///             specification.
  /// Bits 48-63: Reserved for GUID specific use. The use of these bits will vary depending on the
  ///             PartitionTypeGUID. Only the owner of the PartitionTypeGUID is allowed
  ///             to modify these bits. They must be preserved if Bits 0-47 are modified..
  ///
  UINT64    Attributes;
  ///
  /// Null-terminated name of the partition.
  ///
  CHAR16    PartitionName[36];
} EFI_PARTITION_ENTRY;

#pragma pack()
#endif