2019-08-28 00:47:45

by Jerry Snitselaar

Subject: [PATCH 1/2 v2] tpm: provide a way to override the chip returned durations

Patch adds method ->update_durations to override returned
durations in case TPM chip misbehaves for TPM 1.2 drivers.

Cc: Peter Huewe <[email protected]>
Cc: Jarkko Sakkinen <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Signed-off-by: Alexey Klimov <[email protected]>
Signed-off-by: Jerry Snitselaar <[email protected]>
---
v2: newline cleanup as requested by Jarkko

drivers/char/tpm/tpm1-cmd.c | 15 +++++++++++++++
include/linux/tpm.h | 2 ++
2 files changed, 17 insertions(+)

diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index 149e953ca369..ca7158fa6e6c 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -343,6 +343,7 @@ int tpm1_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;

rc = tpm1_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, NULL,
@@ -427,6 +428,20 @@ int tpm1_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 the ability for vendor overrides of duration values in case
+ * of misreporting.
+ */
+ if (chip->ops->update_durations)
+ chip->ops->update_durations(chip, durations);
+
+ if (chip->duration_adjusted) {
+ dev_info(&chip->dev, HW_ERR "Adjusting reported durations.");
+ 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 53c0ea9ec9df..bb1d1ac7081d 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -67,6 +67,8 @@ struct tpm_class_ops {
u8 (*status) (struct tpm_chip *chip);
void (*update_timeouts)(struct tpm_chip *chip,
unsigned long *timeout_cap);
+ void (*update_durations)(struct tpm_chip *chip,
+ unsigned long *duration_cap);
int (*go_idle)(struct tpm_chip *chip);
int (*cmd_ready)(struct tpm_chip *chip);
int (*request_locality)(struct tpm_chip *chip, int loc);
--
2.21.0

2019-08-29 13:29:47

by Jarkko Sakkinen

Subject: Re: [PATCH 1/2 v2] tpm: provide a way to override the chip returned durations

On Tue, Aug 27, 2019 at 05:46:20PM -0700, Jerry Snitselaar wrote:
> Patch adds method ->update_durations to override returned
> durations in case TPM chip misbehaves for TPM 1.2 drivers.
>
> Cc: Peter Huewe <[email protected]>
> Cc: Jarkko Sakkinen <[email protected]>
> Cc: Jason Gunthorpe <[email protected]>
> Signed-off-by: Alexey Klimov <[email protected]>
> Signed-off-by: Jerry Snitselaar <[email protected]>

Reviewed-by: Jarkko Sakkinen <[email protected]>

/Jarkko