tpm_tis: verify locality released before returning from release_locality

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>
Tested-by: Laurent Bigonville <bigon@debian.org>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 5a1f47b43947c80ff3646f6787a4aadb7f224659..d547cd309dbdf2ea16ba0fea5a8f58fdd600ff2d 100644 (file)
--- 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)