From 5e3a3f27cbded417e6d1ea2bb9739b572c09580e Mon Sep 17 00:00:00 2001 From: Stefan Mahnke-Hartmann Date: Fri, 3 Jun 2022 10:41:58 +0200 Subject: tpm: Add upgrade/reduced mode support for TPM1.2 modules In case a TPM in failure mode is detected, the TPM should be accessible through a transparent communication channel for analysing purposes (e.g. TPM_GetTestResult) or a field upgrade. Since a TPM in failure mode has similar reduced functionality as in field upgrade mode, the flag TPM_CHIP_FLAG_FIRMWARE_UPGRADE is also valid. As described in TCG TPM Main Part1 Design Principles, Revision 116, chapter 9.2.1. the TPM also allows an update function in case a TPM is in failure mode. If the TPM in failure mode is detected, the function tpm1_auto_startup() sets TPM_CHIP_FLAG_FIRMWARE_UPGRADE flag, which is used later during driver initialization/deinitialization to disable functionality which makes no sense or will fail in the current TPM state. The following functionality is affected: * Do not register TPM as a hwrng * Do not get pcr allocation * Do not register sysfs entries which provide information impossible to obtain in limited mode Signed-off-by: Stefan Mahnke-Hartmann Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm.h | 1 + drivers/char/tpm/tpm1-cmd.c | 7 ++++++- 2 files changed, 7 insertions(+), 1 deletion(-) (limited to 'drivers/char/tpm') diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index 2163c6ee0d36..24ee4e1cc452 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -55,6 +55,7 @@ enum tpm_addr { #define TPM_WARN_DOING_SELFTEST 0x802 #define TPM_ERR_DEACTIVATED 0x6 #define TPM_ERR_DISABLED 0x7 +#define TPM_ERR_FAILEDSELFTEST 0x1C #define TPM_ERR_INVALID_POSTINIT 38 #define TPM_TAG_RQU_COMMAND 193 diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c index f7dc986fa4a0..cf64c7385105 100644 --- a/drivers/char/tpm/tpm1-cmd.c +++ b/drivers/char/tpm/tpm1-cmd.c @@ -709,7 +709,12 @@ int tpm1_auto_startup(struct tpm_chip *chip) if (rc) goto out; rc = tpm1_do_selftest(chip); - if (rc) { + if (rc == TPM_ERR_FAILEDSELFTEST) { + dev_warn(&chip->dev, "TPM self test failed, switching to the firmware upgrade mode\n"); + /* A TPM in this state possibly allows or needs a firmware upgrade */ + chip->flags |= TPM_CHIP_FLAG_FIRMWARE_UPGRADE; + return 0; + } else if (rc) { dev_err(&chip->dev, "TPM self test failed\n"); goto out; } -- cgit v1.2.3