1 files changed, 92 insertions, 0 deletions
diff --git a/firmware/lib/vboot_nvstorage_rollback.c b/firmware/lib/vboot_nvstorage_rollback.c
new file mode 100644
index 00000000..8e67812d
--- /dev/null
+++ b/firmware/lib/vboot_nvstorage_rollback.c
@@ -0,0 +1,92 @@
+/* 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,
+};
+
+/* 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;
+}