Re: [PATCH v2] tpm_crb: request and relinquish locality 0

From: Jerry Snitselaar
Date: Sun Mar 12 2017 - 15:48:22 EST


Jarkko Sakkinen @ 2017-03-11 13:02 GMT:

> Added two new callbacks to struct tpm_class_ops:
>
> - request_locality
> - relinquish_locality
>
> These are called before sending and receiving data from the TPM. We
> update also tpm_tis_core to use these callbacks. Small modification to
> request_locality() is done so that it returns -EBUSY instead of locality
> number when check_locality() fails.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> ---
> drivers/char/tpm/tpm-interface.c | 9 +++++++++
> drivers/char/tpm/tpm_crb.c | 41 +++++++++++++++++++++++++++++++++++++++-
> drivers/char/tpm/tpm_tis_core.c | 12 ++++--------
> include/linux/tpm.h | 3 ++-
> 4 files changed, 55 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index e38c792..9c56581 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -407,6 +407,12 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> if (chip->dev.parent)
> pm_runtime_get_sync(chip->dev.parent);
>
> + if (chip->ops->request_locality) {
> + rc = chip->ops->request_locality(chip, 0);
> + if (rc)
> + goto out;
> + }
> +
> rc = tpm2_prepare_space(chip, space, ordinal, buf);
> if (rc)
> goto out;
> @@ -466,6 +472,9 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
>
> out:
> + if (chip->ops->relinquish_locality)
> + chip->ops->relinquish_locality(chip, 0, false);
> +
> if (chip->dev.parent)
> pm_runtime_put_sync(chip->dev.parent);
>
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 3245618..15b22a0 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -34,6 +34,15 @@ enum crb_defaults {
> CRB_ACPI_START_INDEX = 1,
> };
>
> +enum crb_loc_ctrl {
> + CRB_LOC_CTRL_REQUEST_ACCESS = BIT(0),
> + CRB_LOC_CTRL_RELINQUISH = BIT(1),
> +};
> +
> +enum crb_loc_state {
> + CRB_LOC_STATE_LOC_ASSIGNED = BIT(1),
> +};
> +
> enum crb_ctrl_req {
> CRB_CTRL_REQ_CMD_READY = BIT(0),
> CRB_CTRL_REQ_GO_IDLE = BIT(1),
> @@ -172,6 +181,35 @@ static int __maybe_unused crb_cmd_ready(struct device *dev,
> return 0;
> }
>
> +static int crb_request_locality(struct tpm_chip *chip, int loc)
> +{
> + struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> +
> + if (!priv->regs_h)
> + return 0;
> +
> + iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h->loc_ctrl);
> + if (!crb_wait_for_reg_32(&priv->regs_h->loc_state,
> + CRB_LOC_STATE_LOC_ASSIGNED, /* mask */
> + CRB_LOC_STATE_LOC_ASSIGNED, /* value */

Should this mask and check bit 7 as well (tpmRegValidSts)? The
table with the definition in the PTP spec says it indicates whether
all other bits contain valid values, but the text above it doesn't
discuss the locAssigned and activeLocality bits with respect to
tpmRegValidSts, so not completely clear.

> + TPM2_TIMEOUT_C)) {
> + dev_warn(&chip->dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
> + return -ETIME;
> + }
> +
> + return 0;
> +}
> +
> +static void crb_relinquish_locality(struct tpm_chip *chip, int loc, bool force)
> +{
> + struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> +
> + if (!priv->regs_h)
> + return;
> +
> + iowrite32(CRB_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);
> +}
> +
> static u8 crb_status(struct tpm_chip *chip)
> {
> struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> @@ -198,7 +236,6 @@ static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
>
> memcpy_fromio(buf, priv->rsp, 6);
> expected = be32_to_cpup((__be32 *) &buf[2]);
> -
> if (expected > count)
> return -EIO;
>
> @@ -279,6 +316,8 @@ static const struct tpm_class_ops tpm_crb = {
> .send = crb_send,
> .cancel = crb_cancel,
> .req_canceled = crb_req_canceled,
> + .request_locality = crb_request_locality,
> + .relinquish_locality = crb_relinquish_locality,
> .req_complete_mask = CRB_DRV_STS_COMPLETE,
> .req_complete_val = CRB_DRV_STS_COMPLETE,
> };
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index fc0e9a2..c3cbe24 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -73,7 +73,7 @@ static int check_locality(struct tpm_chip *chip, int l)
> return -1;
> }
>
> -static void release_locality(struct tpm_chip *chip, int l, int force)
> +static void release_locality(struct tpm_chip *chip, int l, bool force)
> {
> struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> int rc;
> @@ -97,7 +97,7 @@ static int request_locality(struct tpm_chip *chip, int l)
> long rc;
>
> if (check_locality(chip, l) >= 0)
> - return l;
> + return -EBUSY;
>
> rc = tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_REQUEST_USE);
> if (rc < 0)
> @@ -252,7 +252,6 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
>
> out:
> tpm_tis_ready(chip);
> - release_locality(chip, priv->locality, 0);
> return size;
> }
>
> @@ -268,9 +267,6 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
> size_t count = 0;
> bool itpm = priv->flags & TPM_TIS_ITPM_WORKAROUND;
>
> - if (request_locality(chip, 0) < 0)
> - return -EBUSY;
> -
> status = tpm_tis_status(chip);
> if ((status & TPM_STS_COMMAND_READY) == 0) {
> tpm_tis_ready(chip);
> @@ -329,7 +325,6 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
>
> out_err:
> tpm_tis_ready(chip);
> - release_locality(chip, priv->locality, 0);
> return rc;
> }
>
> @@ -390,7 +385,6 @@ static int tpm_tis_send_main(struct tpm_chip *chip, u8 *buf, size_t len)
> return len;
> out_err:
> tpm_tis_ready(chip);
> - release_locality(chip, priv->locality, 0);
> return rc;
> }
>
> @@ -681,6 +675,8 @@ static const struct tpm_class_ops tpm_tis = {
> .send = tpm_tis_send,
> .cancel = tpm_tis_ready,
> .update_timeouts = tpm_tis_update_timeouts,
> + .request_locality = request_locality,
> + .relinquish_locality = release_locality,
> .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
> .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
> .req_canceled = tpm_tis_req_canceled,
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index da158f0..65e05f9 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -48,7 +48,8 @@ struct tpm_class_ops {
> u8 (*status) (struct tpm_chip *chip);
> bool (*update_timeouts)(struct tpm_chip *chip,
> unsigned long *timeout_cap);
> -
> + int (*request_locality)(struct tpm_chip *chip, int loc);
> + void (*relinquish_locality)(struct tpm_chip *chip, int loc, bool force);
> };
>
> #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)