1 /* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
2  * Use of this source code is governed by a BSD-style license that can be
3  * found in the LICENSE file.
4  *
5  * Data structure of Google Binary Block (GBB)
6  */
7 #ifndef VBOOT_REFERENCE_GBB_HEADER_H_
8 #define VBOOT_REFERENCE_GBB_HEADER_H_
9 #include <stdint.h>
10 
11 #define GBB_HEADER_SIZE    128
12 
13 #define GBB_SIGNATURE      "$GBB"
14 #define GBB_SIGNATURE_SIZE 4
15 
16 /*
17  * GBB version constants.
18  *
19  * If the major version is different than the reader can handle, it shouldn't
20  * attempt to parse the GBB.
21  *
22  * If the minor version is different, the reader can still parse it.  If the
23  * minor version is greater than expected, new fields were added in a way which
24  * does not interfere with the old fields.  If it's less than expected, some of
25  * the fields expected by the reader aren't initialized, and the reader should
26  * return default values for those fields.
27  */
28 #define GBB_MAJOR_VER      1
29 #define GBB_MINOR_VER      2
30 /* v1.2 - added field to hold sha256 digest of the HWID */
31 
32 /* Maximum length of a HWID in bytes, counting terminating null. */
33 #define GBB_HWID_MAX_SIZE  256
34 
35 /* Flags for .flags field */
36 /* Reduce the dev screen delay to 2 sec from 30 sec to speedup factory. */
37 #define GBB_FLAG_DEV_SCREEN_SHORT_DELAY   0x00000001
38 /*
39  * BIOS should load option ROMs from arbitrary PCI devices. We'll never enable
40  * this ourselves because it executes non-verified code, but if a customer
41  * wants to void their warranty and set this flag in the read-only flash, they
42  * should be able to do so.
43  */
44 #define GBB_FLAG_LOAD_OPTION_ROMS         0x00000002
45 /*
46  * The factory flow may need the BIOS to boot a non-ChromeOS kernel if the
47  * dev-switch is on. This flag allows that.
48  */
49 #define GBB_FLAG_ENABLE_ALTERNATE_OS      0x00000004
50 /* Force dev switch on, regardless of physical/keyboard dev switch position. */
51 #define GBB_FLAG_FORCE_DEV_SWITCH_ON      0x00000008
52 /* Allow booting from USB in dev mode even if dev_boot_usb=0. */
53 #define GBB_FLAG_FORCE_DEV_BOOT_USB       0x00000010
54 /* Disable firmware rollback protection. */
55 #define GBB_FLAG_DISABLE_FW_ROLLBACK_CHECK  0x00000020
56 /* Allow Enter key to trigger dev->tonorm screen transition */
57 #define GBB_FLAG_ENTER_TRIGGERS_TONORM    0x00000040
58 /* Allow booting Legacy OSes in dev mode even if dev_boot_legacy=0. */
59 #define GBB_FLAG_FORCE_DEV_BOOT_LEGACY    0x00000080
60 /* Allow booting using alternate keys for FAFT servo testing */
61 #define GBB_FLAG_FAFT_KEY_OVERIDE         0x00000100
62 /* Disable EC software sync */
63 #define GBB_FLAG_DISABLE_EC_SOFTWARE_SYNC 0x00000200
64 /* Default to booting legacy OS when dev screen times out */
65 #define GBB_FLAG_DEFAULT_DEV_BOOT_LEGACY  0x00000400
66 /* Disable PD software sync */
67 #define GBB_FLAG_DISABLE_PD_SOFTWARE_SYNC 0x00000800
68 /* Disable shutdown on lid closed */
69 #define GBB_FLAG_DISABLE_LID_SHUTDOWN     0x00001000
70 
71 #ifdef __cplusplus
72 extern "C" {
73 #endif  /* __cplusplus */
74 
75 typedef struct GoogleBinaryBlockHeader
76 {
77 	/* Fields present in version 1.0 */
78 	uint8_t  signature[GBB_SIGNATURE_SIZE]; /* GBB_SIGNATURE "$GBB" */
79 	uint16_t major_version;   /* See GBB_MAJOR_VER */
80 	uint16_t minor_version;   /* See GBB_MINOR_VER */
81 	uint32_t header_size;     /* size of GBB header in bytes */
82 	uint32_t flags;  /* Flags (see GBB_FLAG_*), should be 0 for 1.0. */
83 	/* Offsets (from start of header) and sizes (in bytes) of components */
84 	uint32_t hwid_offset;		/* HWID */
85 	uint32_t hwid_size;
86 	uint32_t rootkey_offset;	/* Root key */
87 	uint32_t rootkey_size;
88 	uint32_t bmpfv_offset;		/* BMP FV */
89 	uint32_t bmpfv_size;
90 	uint32_t recovery_key_offset;	/* Recovery key */
91 	uint32_t recovery_key_size;
92 	/* Added in version 1.2 */
93 	uint8_t  hwid_digest[32];	/* sha256 */
94 
95 	uint8_t  pad[48]; /* To match GBB_HEADER_SIZE.  Initialize to 0. */
96 } __attribute__((packed)) GoogleBinaryBlockHeader;
97 
98 #ifdef __cplusplus
99 }
100 #endif  /* __cplusplus */
101 
102 #endif  /* VBOOT_REFERENCE_GBB_HEADER_H_ */
103