diff options
| author | Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> | 2016-09-02 22:34:17 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-10-16 18:03:41 +0200 |
| commit | 87d6616d78870ae635ae991d63fbe4eb4a7c82c2 (patch) | |
| tree | ebdf5a05253680f21b8ed5dfb25ab19da2ebf4f5 /drivers | |
| parent | 17b6c49b083c73bcb84205afd3e6d6b6a7b19459 (diff) | |
| download | lwn-87d6616d78870ae635ae991d63fbe4eb4a7c82c2.tar.gz lwn-87d6616d78870ae635ae991d63fbe4eb4a7c82c2.zip | |
tpm_crb: fix crb_req_canceled behavior
commit 72fd50e14e46dc0edf360631bdece87c2f066a97 upstream.
The req_canceled() callback is used by tpm_transmit() periodically to
check whether the request has been canceled while it is receiving a
response from the TPM.
The TPM_CRB_CTRL_CANCEL register was cleared already in the crb_cancel
callback, which has two consequences:
* Cancel might not happen.
* req_canceled() always returns zero.
A better place to clear the register is when starting to send a new
command. The behavior of TPM_CRB_CTRL_CANCEL is described in the
section 5.5.3.6 of the PTP specification.
Fixes: 30fc8d138e91 ("tpm: TPM 2.0 CRB Interface")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/char/tpm/tpm_crb.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c index 018c382554ba..1801f382377e 100644 --- a/drivers/char/tpm/tpm_crb.c +++ b/drivers/char/tpm/tpm_crb.c @@ -142,6 +142,11 @@ static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len) struct crb_priv *priv = dev_get_drvdata(&chip->dev); int rc = 0; + /* Zero the cancel register so that the next command will not get + * canceled. + */ + iowrite32(0, &priv->cca->cancel); + if (len > ioread32(&priv->cca->cmd_size)) { dev_err(&chip->dev, "invalid command count value %x %zx\n", @@ -175,8 +180,6 @@ static void crb_cancel(struct tpm_chip *chip) if ((priv->flags & CRB_FL_ACPI_START) && crb_do_acpi_start(chip)) dev_err(&chip->dev, "ACPI Start failed\n"); - - iowrite32(0, &priv->cca->cancel); } static bool crb_req_canceled(struct tpm_chip *chip, u8 status) |