[PATCH v18 3/6] tpm: Handle an exception for TPM Firmware Update mode.

From: amirmizi6
Date: Tue Nov 02 2021 - 11:25:22 EST


From: Amir Mizinski <amirmizi6@xxxxxxxxx>

Add a condition to enable communication with the TPM while the TPM is in
firmware update mode.
In such a case if power was cut during the TPM firmware update, the driver
should ignore the "selftest" command return code (TPM2_RC_UPGRADE or
TPM2_RC_COMMAND_CODE) and skip the rest of the TPM initialization
sequence.

Suggested-by: Benoit Houyere <benoit.houyere@xxxxxx>
Signed-off-by: Amir Mizinski <amirmizi6@xxxxxxxxx>
---
drivers/char/tpm/tpm2-cmd.c | 4 ++++
include/linux/tpm.h | 1 +
2 files changed, 5 insertions(+)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index a25815a..c2b541d 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -729,6 +729,10 @@ int tpm2_auto_startup(struct tpm_chip *chip)
goto out;

rc = tpm2_do_selftest(chip);
+
+ if (rc == TPM2_RC_UPGRADE || rc == TPM2_RC_COMMAND_CODE)
+ return 0;
+
if (rc && rc != TPM2_RC_INITIALIZE)
goto out;

diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index aa11fe3..c5bf934 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -207,6 +207,7 @@ enum tpm2_return_codes {
TPM2_RC_INITIALIZE = 0x0100, /* RC_VER1 */
TPM2_RC_FAILURE = 0x0101,
TPM2_RC_DISABLED = 0x0120,
+ TPM2_RC_UPGRADE = 0x012D,
TPM2_RC_COMMAND_CODE = 0x0143,
TPM2_RC_TESTING = 0x090A, /* RC_WARN */
TPM2_RC_REFERENCE_H0 = 0x0910,
--
2.7.4