Re: [PATCH] tpm_tis: verify locality released before returning from release_locality

[Jerry Snitselaar]

On Sat May 05 18, Jerry Snitselaar wrote:
> For certain tpm chips releasing locality can take long enough that a
> subsequent call to request_locality will see the locality as being
> active when the access register is read in check_locality. So check
> that the locality has been released before returning from
> release_locality.
>
> Cc: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> Cc: Peter Huewe <peterhuewe@xxxxxx>
> Cc: Jason Gunthorpe <jgg@xxxxxxxx>
> Reported-by: Laurent Bigonville <bigon@xxxxxxxxxx>
> Signed-off-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
> ---
> drivers/char/tpm/tpm_tis_core.c | 47 ++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 46 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 5a1f47b43947..d547cd309dbd 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -143,13 +143,58 @@ static bool check_locality(struct tpm_chip *chip, int l)
> 	return false;
> }
>
> +static bool locality_inactive(struct tpm_chip *chip, int l)
> +{
> +	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> +	int rc;
> +	u8 access;
> +
> +	rc = tpm_tis_read8(priv, TPM_ACCESS(l), &access);
> +	if (rc < 0)
> +		return false;
> +
> +	if ((access & (TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY))
> +	    == TPM_ACCESS_VALID)
> +		return true;
> +
> +	return false;
> +}
> +
> static int release_locality(struct tpm_chip *chip, int l)
> {
> 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> +	unsigned long stop, timeout;
> +	long rc;
>
> 	tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY);
>
> -	return 0;
> +	stop = jiffies + chip->timeout_a;
> +
> +	if (chip->flags & TPM_CHIP_FLAG_IRQ) {
> +again:
> +		timeout = stop - jiffies;
> +		if ((long)timeout <= 0)
> +			return -1;
> +
> +		rc = wait_event_interruptible_timeout(priv->int_queue,
> +						      (locality_inactive(chip, l)),
> +						      timeout);
> +
> +		if (rc > 0)
> +			return 0;
> +
> +		if (rc == -ERESTARTSYS && freezing(current)) {
> +			clear_thread_flag(TIF_SIGPENDING);
> +			goto again;
> +		}
> +	} else {
> +		do {
> +			if (locality_inactive(chip, l))
> +				return 0;
> +			tpm_msleep(TPM_TIMEOUT);
> +		} while (time_before(jiffies, stop));
> +	}
> +	return -1;
> }
>
> static int request_locality(struct tpm_chip *chip, int l)
> --
> 2.15.0

Laurent,

Can you try this patch with your system since it is the one
that has exhibited the problem so far. I've tested on a
tpm2.0 and tpm1.2 system here.

Regards,
Jerry