[PATCH REVIEW 1/2] tpm: provide a way to override the chip returned durations
From: Alexey Klimov <hidden>
Date: 2018-12-14 13:21:19
Subsystem:
the rest, tpm device driver · Maintainers:
Linus Torvalds, Peter Huewe, Jarkko Sakkinen
Patch adds method ->update_durations to override returned durations in case TPM chip misbehaves for TPM 1.2 drivers. Cc: Jerry Snitselaar <redacted> Signed-off-by: Alexey Klimov <redacted> --- drivers/char/tpm/tpm-interface.c | 18 ++++++++++++++++++ include/linux/tpm.h | 2 ++ 2 files changed, 20 insertions(+)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 129f640424b7..5cb90918938d 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c@@ -768,6 +768,7 @@ int tpm_get_timeouts(struct tpm_chip *chip) { cap_t cap; unsigned long timeout_old[4], timeout_chip[4], timeout_eff[4]; + unsigned long durations[3]; ssize_t rc; if (chip->flags & TPM_CHIP_FLAG_HAVE_TIMEOUTS)
@@ -877,6 +878,23 @@ int tpm_get_timeouts(struct tpm_chip *chip) usecs_to_jiffies(be32_to_cpu(cap.duration.tpm_long)); chip->duration[TPM_LONG_LONG] = 0; /* not used under 1.2 */ + /* + * Provide ability for vendor overrides of duration values in case + * of misreporting. + */ + if (chip->ops->update_durations != NULL) + chip->duration_adjusted = + chip->ops->update_durations(chip, durations); + + /* Report and set adjusted timeouts */ + if (chip->duration_adjusted) { + + dev_info(&chip->dev, HW_ERR "Adjusting reported durations\n"); + chip->duration[TPM_SHORT] = durations[0]; + chip->duration[TPM_MEDIUM] = durations[1]; + chip->duration[TPM_LONG] = durations[2]; + } + /* The Broadcom BCM0102 chipset in a Dell Latitude D820 gets the above * value wrong and apparently reports msecs rather than usecs. So we * fix up the resulting too-small TPM_SHORT value to make things work.
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 4609b94142d4..d6018431b478 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h@@ -43,6 +43,8 @@ struct tpm_class_ops { u8 (*status) (struct tpm_chip *chip); bool (*update_timeouts)(struct tpm_chip *chip, unsigned long *timeout_cap); + bool (*update_durations)(struct tpm_chip *chip, + unsigned long *durations_cap); int (*go_idle)(struct tpm_chip *chip); int (*cmd_ready)(struct tpm_chip *chip); int (*request_locality)(struct tpm_chip *chip, int loc);
--
2.14.4