From 8866a28836924a0bfa84f1cbf574eb5138b7dec4 Mon Sep 17 00:00:00 2001 From: Jarkko Sakkinen Date: Fri, 2 Sep 2016 22:34:17 +0300 Subject: 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 Signed-off-by: Greg Kroah-Hartman --- drivers/char/tpm/tpm_crb.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c index 61e64293b765..2b21398c3adc 100644 --- a/drivers/char/tpm/tpm_crb.c +++ b/drivers/char/tpm/tpm_crb.c @@ -149,6 +149,11 @@ static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len) struct crb_priv *priv = chip->vendor.priv; int rc = 0; + /* Zero the cancel register so that the next command will not get + * canceled. + */ + iowrite32(0, &priv->cca->cancel); + if (len > le32_to_cpu(ioread32(&priv->cca->cmd_size))) { dev_err(&chip->dev, "invalid command count value %x %zx\n", @@ -182,8 +187,6 @@ 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) -- cgit v1.2.3