cr50: implement _plat__ShallSurviveOwnerClear

To persist some special indexes over TPM owner clear,
implement a _plat__ShallSurviveOwnerClear callback that
tells TPM2 stack, which indexes shall be kept.

As of now, only FWMP index shall be retained.

BRANCH=cr50
BUG=b:112099050
TEST=1) Create FWMP.
        cryptohome --action=tpm_take_ownership [and wait]
        cryptohome --action=set_firmware_management_parameters \
                   --flags=0xbb00
     2) Clear the owner.
        crossystem clear_tpm_owner_request=1
        reboot
     3) Verify that FWMP still exists, but cannot be overwritten.
        cryptohome --action=get_firmware_management_parameters
        (but the following fails:)
        cryptohome --action=set_firmware_management_parameters \
                   --flags=0xcc00
        cryptohome --action=remove_firmware_management_parameters
     4) Verify that it can be written/removed after taking ownership.
        cryptohome --action=tpm_take_ownership [and wait]
        cryptohome --action=set_firmware_management_parameters \
                   --flags=0xdd00
        cryptohome --action=remove_firmware_management_parameters

Change-Id: I3236d61adbfb7665c0a4bfc1a7addeaa1f0eb3ee
Signed-off-by: Andrey Pronin <apronin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1159854
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/tpm_nvmem.h b/include/tpm_nvmem.h
new file mode 100644
index 0000000000..2508c9ae65
--- /dev/null
+++ b/include/tpm_nvmem.h
@@ -0,0 +1,13 @@
+/* Copyright 2018 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.
+ *
+ * TPM NVMEM definitions.
+ */
+#ifndef __CROS_EC_TPM_NVMEM_H
+#define __CROS_EC_TPM_NVMEM_H
+
+#define FIRMWARE_NV_INDEX       0x1007
+#define FWMP_NV_INDEX		0x100a
+
+#endif /* __CROS_EC_TPM_NVMEM_H */