The current release locality code seems to be based on the
misunderstanding that the TPM interrupts when a locality is released:
it doesn't, only when the locality is acquired.
Furthermore, there seems to be no point in waiting for the locality to
be released. All it does is penalize the last TPM user. However, if
there's no next TPM user, this is a pointless wait and if there is a
next TPM user, they'll pay the penalty waiting for the new locality
(or possibly not if it's the same as the old locality).
Fix the code by making release_locality as simple write to release
with no waiting for completion.
Fixes: 33bafe90824b ("tpm_tis: verify locality released before returning from release_locality")
Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
---
v2: added fixes
---
drivers/char/tpm/tpm_tis_core.c | 47 +--------------------------------
1 file changed, 1 insertion(+), 46 deletions(-)
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index f3ecde8df47d..431919d5f48a 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -135,58 +135,13 @@ 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);
- 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;
+ return 0;
}
static int request_locality(struct tpm_chip *chip, int l)
--
2.28.0
