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/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Non-volatile storage routines.
*/
#include "sysincludes.h"
#include "crc8.h"
#include "utility.h"
#include "vboot_common.h"
#include "vboot_nvstorage.h"
#include "rollback_index.h"
/* These are the fields of the nvram that we want to back up. */
static const VbNvParam backup_params[] = {
VBNV_KERNEL_FIELD,
VBNV_LOCALIZATION_INDEX,
VBNV_DEV_BOOT_USB,
VBNV_DEV_BOOT_LEGACY,
VBNV_DEV_BOOT_SIGNED_ONLY,
VBNV_DEV_BOOT_FASTBOOT_FULL_CAP,
};
/* We can't back things up if there isn't enough storage. */
BUILD_ASSERT(VBNV_BLOCK_SIZE <= BACKUP_NV_SIZE);
int RestoreNvFromBackup(VbNvContext *vnc)
{
VbNvContext bvnc;
uint32_t value;
int i;
VBDEBUG(("TPM: %s()\n", __func__));
if (TPM_SUCCESS != RollbackBackupRead(bvnc.raw))
return 1;
VbNvSetup(&bvnc);
if (bvnc.regenerate_crc) {
VBDEBUG(("TPM: Oops, backup is no good.\n"));
return 1;
}
for (i = 0; i < ARRAY_SIZE(backup_params); i++) {
VbNvGet(&bvnc, backup_params[i], &value);
VbNvSet(vnc, backup_params[i], value);
}
/* VbNvTeardown(&bvnc); is not needed. We're done with it. */
return 0;
}
int SaveNvToBackup(VbNvContext *vnc)
{
VbNvContext bvnc;
uint32_t value;
int i;
VBDEBUG(("TPM: %s()\n", __func__));
/* Read it first. No point in writing the same data. */
if (TPM_SUCCESS != RollbackBackupRead(bvnc.raw))
return 1;
VbNvSetup(&bvnc);
VBDEBUG(("TPM: existing backup is %s\n",
bvnc.regenerate_crc ? "bad" : "good"));
for (i = 0; i < ARRAY_SIZE(backup_params); i++) {
VbNvGet(vnc, backup_params[i], &value);
VbNvSet(&bvnc, backup_params[i], value);
}
VbNvTeardown(&bvnc);
if (!bvnc.raw_changed) {
VBDEBUG(("TPM: Nothing's changed, not writing backup\n"));
/* Clear the request flag, since we're happy. */
VbNvSet(vnc, VBNV_BACKUP_NVRAM_REQUEST, 0);
return 0;
}
if (TPM_SUCCESS == RollbackBackupWrite(bvnc.raw)) {
/* Clear the request flag if we wrote successfully too */
VbNvSet(vnc, VBNV_BACKUP_NVRAM_REQUEST, 0);
return 0;
}
VBDEBUG(("TPM: Sorry, couldn't write backup.\n"));
return 1;
}
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