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/*
* 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 <console/console.h>
#include <ec/google/chromeec/ec.h>
#include <rmodule.h>
#include <string.h>
#include <security/vboot/misc.h>
#include <security/vboot/symbols.h>
#include <security/vboot/vboot_common.h>
/* Ensure vboot configuration is valid: */
_Static_assert(CONFIG(VBOOT_STARTS_IN_BOOTBLOCK) +
CONFIG(VBOOT_STARTS_IN_ROMSTAGE) == 1,
"vboot must either start in bootblock or romstage (not both!)");
_Static_assert(CONFIG(VBOOT_STARTS_IN_BOOTBLOCK) ||
!CONFIG(VBOOT_MIGRATE_WORKING_DATA),
"no need to migrate working data after CBMEM is already up!");
_Static_assert(!CONFIG(VBOOT_SEPARATE_VERSTAGE) ||
CONFIG(VBOOT_STARTS_IN_BOOTBLOCK),
"stand-alone verstage must start in (i.e. after) bootblock");
_Static_assert(!CONFIG(VBOOT_RETURN_FROM_VERSTAGE) ||
CONFIG(VBOOT_SEPARATE_VERSTAGE),
"return from verstage only makes sense for separate verstages");
/* 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 (CONFIG(VBOOT_SEPARATE_VERSTAGE))
return ENV_VERSTAGE;
else if (CONFIG(VBOOT_STARTS_IN_ROMSTAGE))
return ENV_ROMSTAGE;
else if (CONFIG(VBOOT_STARTS_IN_BOOTBLOCK))
return ENV_BOOTBLOCK;
else
die("impossible!");
}
static int verstage_should_load(void)
{
if (CONFIG(VBOOT_SEPARATE_VERSTAGE))
return ENV_BOOTBLOCK;
else
return 0;
}
static int vboot_executed CAR_GLOBAL;
int vb2_logic_executed(void)
{
/* If we are in a stage that would load the verstage or execute the
vboot logic directly, we store the answer in a global. */
if (verstage_should_load() || verification_should_run())
return car_get_var(vboot_executed);
if (CONFIG(VBOOT_STARTS_IN_BOOTBLOCK)) {
/* All other stages are "after the bootblock" */
return !ENV_BOOTBLOCK;
} else if (CONFIG(VBOOT_STARTS_IN_ROMSTAGE)) {
/* Post-RAM stages are "after the romstage" */
#ifdef __PRE_RAM__
return 0;
#else
return 1;
#endif
} else {
die("impossible!");
}
}
static void vboot_prepare(void)
{
if (verification_should_run()) {
/* Note: this path is not used for VBOOT_RETURN_FROM_VERSTAGE */
verstage_main();
car_set_var(vboot_executed, 1);
vb2_save_recovery_reason_vbnv();
} 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 (!CONFIG(VBOOT_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_STARTS_IN_ROMSTAGE 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 && CONFIG(VBOOT_STARTS_IN_ROMSTAGE))
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,
};
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