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SubjectRe: [PATCH] tpm_tis: verify locality released before returning from release_locality
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@linux.intel.com>
>Cc: Peter Huewe <peterhuewe@gmx.de>
>Cc: Jason Gunthorpe <jgg@ziepe.ca>
>Reported-by: Laurent Bigonville <bigon@debian.org>
>Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
>---
> 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

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