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char/tpm: Check return code of wait_for_tpm_stat

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In some weird cases it might be possible that the TPM does not set
STS.VALID within the given timeout time (or ever) but sets STS.EXPECT
(STS=0x0C) In this case the driver gets stuck in the while loop of
tpm_tis_send_data and loops endlessly.

Checking the return value of wait_for_tpm_stat fixes this and the driver
bails out correctly.  While at it fixing all other users since if the
TPM does not manage to set STS.VALID within the reasonable timeframe
something is definitely wrong and the driver should react correctly.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
This commit is contained in:
Peter Huewe 2016-10-11 15:01:01 +03:00 committed by Jarkko Sakkinen
parent e74f2f76c1
commit 2c97f6f20c
1 changed files with 20 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/char/tpm/tpm_tis_core.c
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@ -180,11 +180,13 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
int size = 0, burstcnt, rc;
while (size < count &&
wait_for_tpm_stat(chip,
while (size < count) {
rc = wait_for_tpm_stat(chip,
TPM_STS_DATA_AVAIL | TPM_STS_VALID,
chip->timeout_c,
&priv->read_queue, true) == 0) {
&priv->read_queue, true);
if (rc < 0)
return rc;
burstcnt = min_t(int, get_burstcount(chip), count - size);
rc = tpm_tis_read_bytes(priv, TPM_DATA_FIFO(priv->locality),
@ -229,8 +231,11 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
goto out;
}
wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
&priv->int_queue, false);
if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
&priv->int_queue, false) < 0) {
size = -ETIME;
goto out;
}
status = tpm_tis_status(chip);
if (status & TPM_STS_DATA_AVAIL) { /* retry? */
dev_err(&chip->dev, "Error left over data\n");
@ -279,8 +284,11 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
count += burstcnt;
wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
&priv->int_queue, false);
if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
&priv->int_queue, false) < 0) {
rc = -ETIME;
goto out_err;
}
status = tpm_tis_status(chip);
if (!itpm && (status & TPM_STS_DATA_EXPECT) == 0) {
rc = -EIO;
@ -293,8 +301,11 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
if (rc < 0)
goto out_err;
wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
&priv->int_queue, false);
if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
&priv->int_queue, false) < 0) {
rc = -ETIME;
goto out_err;
}
status = tpm_tis_status(chip);
if (!itpm && (status & TPM_STS_DATA_EXPECT) != 0) {
rc = -EIO;