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authorJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2016-09-02 22:34:17 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-10-16 18:03:41 +0200
commit87d6616d78870ae635ae991d63fbe4eb4a7c82c2 (patch)
parent17b6c49b083c73bcb84205afd3e6d6b6a7b19459 (diff)
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 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>
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)) {
"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)