summaryrefslogtreecommitdiff
path: root/src/vboot/vboot_loader.c
blob: 207aadaac7c4a4e6f2262c7fd48b43e7c893fa16 (plain)
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
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
/*
 * This file is part of the coreboot project.
 *
 * Copyright 2015 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 <cbfs.h>
#include <cbmem.h>
#include <console/console.h>
#include <ec/google/chromeec/ec.h>
#include <rmodule.h>
#include <rules.h>
#include <string.h>
#include <vboot/misc.h>
#include <vboot/symbols.h>
#include <vboot/vboot_common.h>

/* The stage loading code is compiled and entered from multiple stages. The
 * helper functions below attempt to provide more clarity on when certain
 * code should be called. */

static int verification_should_run(void)
{
	if (ENV_VERSTAGE && IS_ENABLED(CONFIG_SEPARATE_VERSTAGE))
		return 1;

	if (!IS_ENABLED(CONFIG_SEPARATE_VERSTAGE)) {
		if (ENV_ROMSTAGE &&
		    IS_ENABLED(CONFIG_VBOOT_STARTS_IN_ROMSTAGE))
			return 1;
		if (ENV_BOOTBLOCK &&
		    IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK))
			return 1;
	}

	return 0;
}

static int verstage_should_load(void)
{
	if (!IS_ENABLED(CONFIG_SEPARATE_VERSTAGE))
		return 0;

	if (ENV_ROMSTAGE && IS_ENABLED(CONFIG_VBOOT_STARTS_IN_ROMSTAGE))
		return 1;

	if (ENV_BOOTBLOCK && IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK))
		return 1;

	return 0;
}

static int vboot_executed CAR_GLOBAL;

int vb2_logic_executed(void)
{
	/* If this stage is supposed to run the vboot logic ensure it has been
	 * executed. */
	if (verification_should_run() && car_get_var(vboot_executed))
		return 1;

	/* If this stage is supposed to load verstage and verstage is returning
	 * back to the calling stage check that it has been executed. */
	if (verstage_should_load() && IS_ENABLED(CONFIG_RETURN_FROM_VERSTAGE))
		if (car_get_var(vboot_executed))
			return 1;

	/* Handle all other stages post vboot execution. */
	if (!ENV_BOOTBLOCK) {
		if (IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK))
			return 1;
		if (IS_ENABLED(CONFIG_VBOOT_STARTS_IN_ROMSTAGE) &&
				!ENV_ROMSTAGE)
			return 1;
	}

	return 0;
}

static void vboot_prepare(void)
{
	if (verification_should_run()) {
		/*
		 * Note that this path isn't taken when
		 * CONFIG_RETURN_FROM_VERSTAGE is employed.
		 */
		verstage_main();
		car_set_var(vboot_executed, 1);
		vb2_save_recovery_reason_vbnv();

		/*
		 * Avoid double memory retrain when the EC is running RW code
		 * and a recovery request came in through an EC host event. The
		 * double retrain happens because the EC won't be rebooted
		 * until kernel verification notices the EC isn't running RO
		 * code which is after memory training. Therefore, reboot the
		 * EC after we've saved the potential recovery request so it's
		 * not lost. Lastly, only perform this sequence on x86
		 * platforms since those are the ones that currently do a
		 * costly memory training in recovery mode.
		 */
		if (IS_ENABLED(CONFIG_EC_GOOGLE_CHROMEEC) &&
			IS_ENABLED(CONFIG_ARCH_X86))
			google_chromeec_early_init();

	} else if (verstage_should_load()) {
		struct cbfsf file;
		struct prog verstage =
			PROG_INIT(PROG_VERSTAGE,
				CONFIG_CBFS_PREFIX "/verstage");

		printk(BIOS_DEBUG, "VBOOT: Loading verstage.\n");

		/* load verstage from RO */
		if (cbfs_boot_locate(&file, prog_name(&verstage), NULL))
			die("failed to load verstage");

		cbfs_file_data(prog_rdev(&verstage), &file);

		if (cbfs_prog_stage_load(&verstage))
			die("failed to load verstage");

		/* verify and select a slot */
		prog_run(&verstage);

		/* This is not actually possible to hit this condition at
		 * runtime, but this provides a hint to the compiler for dead
		 * code elimination below. */
		if (!IS_ENABLED(CONFIG_RETURN_FROM_VERSTAGE))
			return;

		car_set_var(vboot_executed, 1);
	}

	/*
	 * Fill in vboot cbmem objects before moving to ramstage so all
	 * downstream users have access to vboot results. This path only
	 * applies to platforms employing VBOOT_DYNAMIC_WORK_BUFFER because
	 * cbmem comes online prior to vboot verification taking place. For
	 * other platforms the vboot cbmem objects are initialized when
	 * cbmem comes online.
	 */
	if (ENV_ROMSTAGE && IS_ENABLED(CONFIG_VBOOT_DYNAMIC_WORK_BUFFER)) {
		vb2_store_selected_region();
		vboot_fill_handoff();
	}
}

static int vboot_locate(struct cbfs_props *props)
{
	struct region selected_region;

	/* Don't honor vboot results until the vboot logic has run. */
	if (!vb2_logic_executed())
		return -1;

	if (vb2_get_selected_region(&selected_region))
		return -1;

	props->offset = region_offset(&selected_region);
	props->size = region_sz(&selected_region);

	return 0;
}

const struct cbfs_locator vboot_locator = {
	.name = "VBOOT",
	.prepare = vboot_prepare,
	.locate = vboot_locate,
};