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