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authorStefan Mahnke-Hartmann <stefan.mahnke-hartmann@infineon.com>2022-06-03 11:41:58 +0300
committerJarkko Sakkinen <jarkko@kernel.org>2022-08-03 23:56:19 +0300
commit5e3a3f27cbded417e6d1ea2bb9739b572c09580e (patch)
treececaa173565ccfad09d852989a2477d9d23fbbcf /drivers/char/tpm
parent200e340f2196d7fd427a5810d06e893b932f145a (diff)
downloadlinux-5e3a3f27cbded417e6d1ea2bb9739b572c09580e.tar.xz
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 <stefan.mahnke-hartmann@infineon.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Diffstat (limited to 'drivers/char/tpm')
-rw-r--r--drivers/char/tpm/tpm.h1
-rw-r--r--drivers/char/tpm/tpm1-cmd.c7
2 files changed, 7 insertions, 1 deletions
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;
}