xref: /aosp_15_r20/external/vboot_reference/firmware/include/gpt.h (revision 8617a60d3594060b7ecbd21bc622a7c14f3cf2bc)
1 /* Copyright 2013 The ChromiumOS Authors
2  * Use of this source code is governed by a BSD-style license that can be
3  * found in the LICENSE file.
4  *
5  * Defines UEFI related structure. See more details in the UEFI spec.
6  *
7  * To download UEFI standard, please visit UEFI homepage:
8  *    http://www.uefi.org/
9  */
10 
11 #ifndef VBOOT_REFERENCE_CGPTLIB_GPT_H_
12 #define VBOOT_REFERENCE_CGPTLIB_GPT_H_
13 
14 #include <stdint.h>
15 
16 #ifdef __cplusplus
17 extern "C" {
18 #endif  /* __cplusplus */
19 
20 /* From the specification */
21 #define GPT_HEADER_SIGNATURE_SIZE 8
22 #define GPT_HEADER_REVISION 0x00010000
23 #define GPT_HEADER_SIGNATURE  "EFI PART"
24 
25 /* From https://chromium-review.googlesource.com/31264 */
26 #define GPT_HEADER_SIGNATURE2 "CHROMEOS"
27 
28 /* From http://crosbug.com/p/52595 */
29 #define GPT_HEADER_SIGNATURE_IGNORED "IGNOREME"
30 
31 /*
32  * The first 3 numbers should be stored in network-endian format according to
33  * the GUID RFC.  The UEFI spec appendix A claims they should be stored in
34  * little-endian format.  But they need to be _displayed_ in network-endian
35  * format, which is also how they're documented in the specs.
36  *
37  * Since what we have here are little-endian constants, they're byte-swapped
38  * from the normal display order.
39  */
40 #define GPT_ENT_TYPE_UNUSED \
41 	{{{0x00000000,0x0000,0x0000,0x00,0x00,{0x00,0x00,0x00,0x00,0x00,0x00}}}}
42 #define GPT_ENT_TYPE_EFI \
43 	{{{0xc12a7328,0xf81f,0x11d2,0xba,0x4b,{0x00,0xa0,0xc9,0x3e,0xc9,0x3b}}}}
44 #define GPT_ENT_TYPE_CHROMEOS_FIRMWARE \
45 	{{{0xcab6e88e,0xabf3,0x4102,0xa0,0x7a,{0xd4,0xbb,0x9b,0xe3,0xc1,0xd3}}}}
46 #define GPT_ENT_TYPE_CHROMEOS_KERNEL \
47 	{{{0xfe3a2a5d,0x4f32,0x41a7,0xb7,0x25,{0xac,0xcc,0x32,0x85,0xa3,0x09}}}}
48 #define GPT_ENT_TYPE_CHROMEOS_ROOTFS \
49 	{{{0x3cb8e202,0x3b7e,0x47dd,0x8a,0x3c,{0x7f,0xf2,0xa1,0x3c,0xfc,0xec}}}}
50 #define GPT_ENT_TYPE_CHROMEOS_RESERVED \
51 	{{{0x2e0a753d,0x9e48,0x43b0,0x83,0x37,{0xb1,0x51,0x92,0xcb,0x1b,0x5e}}}}
52 #define GPT_ENT_TYPE_BASIC_DATA \
53 	{{{0xebd0a0a2,0xb9e5,0x4433,0x87,0xc0,{0x68,0xb6,0xb7,0x26,0x99,0xc7}}}}
54 #define GPT_ENT_TYPE_LINUX_FS \
55 	{{{0x0fc63daf,0x8483,0x4772,0x8e,0x79,{0x3d,0x69,0xd8,0x47,0x7d,0xe4}}}}
56 #define GPT_ENT_TYPE_CHROMEOS_MINIOS \
57 	{{{0x09845860,0x705f,0x4bb5,0xb1,0x6c,{0x8a,0x8a,0x09,0x9c,0xaf,0x52}}}}
58 #define GPT_ENT_TYPE_CHROMEOS_HIBERNATE \
59 	{{{0x3f0f8318,0xf146,0x4e6b,0x82,0x22,{0xc2,0x8c,0x8f,0x02,0xe0,0xd5}}}}
60 
61 #define UUID_NODE_LEN 6
62 #define GUID_SIZE 16
63 
64 /* GUID definition. Defined in appendix A of UEFI standard. */
65 typedef struct {
66 	union {
67 		struct {
68 			uint32_t time_low;
69 			uint16_t time_mid;
70 			uint16_t time_high_and_version;
71 			uint8_t clock_seq_high_and_reserved;
72 			uint8_t clock_seq_low;
73 			uint8_t node[UUID_NODE_LEN];
74 		} Uuid;
75 		uint8_t raw[GUID_SIZE];
76 	} u;
77 } __attribute__((packed)) Guid;
78 
79 #define GUID_EXPECTED_SIZE GUID_SIZE
80 
81 /*
82  * GPT header defines how many partitions exist on a drive and sectors managed.
83  * For every drive device, there are 2 headers, primary and secondary.  Most of
84  * the fields are duplicates except my_lba and entries_lba.
85  *
86  * You may find more details in chapter 5 of the UEFI standard.
87  */
88 typedef struct {
89 	char signature[GPT_HEADER_SIGNATURE_SIZE];
90 	uint32_t revision;
91 	uint32_t size;
92 	uint32_t header_crc32;
93 	uint32_t reserved_zero;
94 	uint64_t my_lba;
95 	uint64_t alternate_lba;
96 	uint64_t first_usable_lba;
97 	uint64_t last_usable_lba;
98 	Guid disk_uuid;
99 	uint64_t entries_lba;
100 	uint32_t number_of_entries;
101 	uint32_t size_of_entry;
102 	uint32_t entries_crc32;
103 	/* Remainder of sector is reserved and should be 0 */
104 } __attribute__((packed)) GptHeader;
105 
106 #define GPTHEADER_EXPECTED_SIZE 92
107 
108 /*
109  * GPT partition entry defines the starting and ending LBAs of a partition.  It
110  * also contains the unique GUID, type, and attribute bits.
111  *
112  * You may find more details in chapter 5 of the UEFI standard.
113  */
114 typedef struct {
115 	Guid type;
116 	Guid unique;
117 	uint64_t starting_lba;
118 	uint64_t ending_lba;
119 	union {
120 		struct {
121 			uint8_t required:1;
122 			uint8_t efi_ignore:1;
123 			uint8_t legacy_boot:1;
124 			uint8_t reserved1:5;
125 			uint8_t reserved2;
126 			uint16_t reserved[2];
127 			uint16_t gpt_att;
128 		} __attribute__((packed)) fields;
129 		uint64_t whole;
130 	} attrs;
131 	uint16_t name[36];  /* UTF-16 encoded partition name */
132 	/* Remainder of entry is reserved and should be 0 */
133 } __attribute__((packed)) GptEntry;
134 
135 #define GPTENTRY_EXPECTED_SIZE 128
136 
137 #ifdef __cplusplus
138 }
139 #endif  /* __cplusplus */
140 
141 #endif  /* VBOOT_REFERENCE_CGPTLIB_GPT_H_ */
142