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
|
/*
* This file is part of the coreboot project.
*
* Copyright (C) 2016 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <arch/early_variables.h>
#include <string.h>
#include <types.h>
#include <vboot/vbnv.h>
#include <vboot/vbnv_layout.h>
static int vbnv_initialized CAR_GLOBAL;
static uint8_t vbnv[VBOOT_VBNV_BLOCK_SIZE] CAR_GLOBAL;
/* Wrappers for accessing the variables marked as CAR_GLOBAL. */
static inline int is_vbnv_initialized(void)
{
return car_get_var(vbnv_initialized);
}
static inline uint8_t *vbnv_data_addr(int index)
{
uint8_t *vbnv_arr = car_get_var_ptr(vbnv);
return &vbnv_arr[index];
}
static inline uint8_t vbnv_data(int index)
{
return *vbnv_data_addr(index);
}
/* Return CRC-8 of the data, using x^8 + x^2 + x + 1 polynomial. */
static uint8_t crc8_vbnv(const uint8_t *data, int len)
{
unsigned crc = 0;
int i, j;
for (j = len; j; j--, data++) {
crc ^= (*data << 8);
for (i = 8; i; i--) {
if (crc & 0x8000)
crc ^= (0x1070 << 3);
crc <<= 1;
}
}
return (uint8_t) (crc >> 8);
}
static void reset_vbnv(uint8_t *vbnv_copy)
{
memset(vbnv_copy, 0, VBOOT_VBNV_BLOCK_SIZE);
}
/* Read VBNV data into cache. */
static void vbnv_setup(void)
{
if (!is_vbnv_initialized()) {
read_vbnv(vbnv_data_addr(0));
car_set_var(vbnv_initialized, 1);
}
}
/* Verify VBNV header and checksum. */
int verify_vbnv(uint8_t *vbnv_copy)
{
return (HEADER_SIGNATURE == (vbnv_copy[HEADER_OFFSET] & HEADER_MASK)) &&
(crc8_vbnv(vbnv_copy, CRC_OFFSET) == vbnv_copy[CRC_OFFSET]);
}
/* Re-generate VBNV checksum. */
void regen_vbnv_crc(uint8_t *vbnv_copy)
{
vbnv_copy[CRC_OFFSET] = crc8_vbnv(vbnv_copy, CRC_OFFSET);
}
/*
* Read VBNV data from configured storage backend.
* If VBNV verification fails, reset the vbnv copy.
*/
void read_vbnv(uint8_t *vbnv_copy)
{
if (IS_ENABLED(CONFIG_VBOOT_VBNV_CMOS))
read_vbnv_cmos(vbnv_copy);
else if (IS_ENABLED(CONFIG_VBOOT_VBNV_EC))
read_vbnv_ec(vbnv_copy);
else if (IS_ENABLED(CONFIG_VBOOT_VBNV_FLASH))
read_vbnv_flash(vbnv_copy);
/* Check data for consistency */
if (!verify_vbnv(vbnv_copy))
reset_vbnv(vbnv_copy);
}
/*
* Write VBNV data to configured storage backend.
* This assumes that the caller has updated the CRC already.
*/
void save_vbnv(const uint8_t *vbnv_copy)
{
if (IS_ENABLED(CONFIG_VBOOT_VBNV_CMOS))
save_vbnv_cmos(vbnv_copy);
else if (IS_ENABLED(CONFIG_VBOOT_VBNV_EC))
save_vbnv_ec(vbnv_copy);
else if (IS_ENABLED(CONFIG_VBOOT_VBNV_FLASH))
save_vbnv_flash(vbnv_copy);
/* Clear initialized flag to force cached data to be updated */
car_set_var(vbnv_initialized, 0);
}
/* Save a recovery reason into VBNV. */
void set_recovery_mode_into_vbnv(int recovery_reason)
{
uint8_t vbnv_copy[VBOOT_VBNV_BLOCK_SIZE];
read_vbnv(vbnv_copy);
vbnv_copy[RECOVERY_OFFSET] = recovery_reason;
vbnv_copy[CRC_OFFSET] = crc8_vbnv(vbnv_copy, CRC_OFFSET);
save_vbnv(vbnv_copy);
}
/* Read the recovery reason from VBNV. */
int get_recovery_mode_from_vbnv(void)
{
vbnv_setup();
return vbnv_data(RECOVERY_OFFSET);
}
/* Read the BOOT_OPROM_NEEDED flag from VBNV. */
int vboot_wants_oprom(void)
{
vbnv_setup();
return (vbnv_data(BOOT_OFFSET) & BOOT_OPROM_NEEDED) ? 1 : 0;
}
void vbnv_init(uint8_t *vbnv_copy)
{
read_vbnv(vbnv_copy);
}
|
