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 <[email protected]>
Cc: Peter Huewe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Reported-by: Laurent Bigonville <[email protected]>
Signed-off-by: Jerry Snitselaar <[email protected]>
Tested-by: Laurent Bigonville <[email protected]>
Reviewed-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>

Author: snits

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)