diff mbox series

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

Message ID 20211102152056.241769-4-amirmizi6@gmail.com (mailing list archive)
State New, archived
Headers show
Series Add tpm i2c ptp driver | expand

Commit Message

Amir Mizinski Nov. 2, 2021, 3:20 p.m. UTC 
From: Amir Mizinski <amirmizi6@gmail.com>

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@st.com>
Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/tpm2-cmd.c | 4 ++++
 include/linux/tpm.h         | 1 +
 2 files changed, 5 insertions(+)

Comments

Jarkko Sakkinen Nov. 2, 2021, 8:32 p.m. UTC | #1 
On Tue, 2021-11-02 at 17:20 +0200, amirmizi6@gmail.com wrote:
> From: Amir Mizinski <amirmizi6@gmail.com>
> 
> 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@st.com>
> Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>

This is a half-baked handling of the FW upgrade mode.

There's another patch in progress that aims to do proper handling
for it:

https://lore.kernel.org/linux-integrity/20210930160241.9691-1-borysmn@axis.com/

I CC'd Borys for further comments/discussion.

/Jarkko
diff mbox series

Patch

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,