Re: [PATCH v8 16/17] tpm: take TPM chip power gating out of tpm_transmit()

[Stefan Berger <stefanb@linux.ibm.com>]

On 11/16/18 7:38 AM, Jarkko Sakkinen wrote:
> Call tpm_chip_start() and tpm_chip_stop() in
>
> * tpm_try_get_ops() and tpm_put_ops()
> * tpm_chip_register()
> * tpm2_del_space()
>
> And remove these calls from tpm_transmit(). The core reason for this
> change is that in tpm_vtpm_proxy a locality change requires a virtual
> TPM command (a command made up just for that driver).
>
> The consequence of this is that this commit removes the remaining nested
> calls.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>   drivers/char/tpm/tpm-chip.c       | 21 ++++++++-------------
>   drivers/char/tpm/tpm-interface.c  |  4 ----
>   drivers/char/tpm/tpm.h            |  9 ---------
>   drivers/char/tpm/tpm2-space.c     |  5 ++++-
>   drivers/char/tpm/tpm_vtpm_proxy.c |  3 +--
>   5 files changed, 13 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 65f1561eba81..837d44fa0797 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -41,9 +41,6 @@ static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
>   {
>   	int rc;
>
> -	if (flags & TPM_TRANSMIT_NESTED)
> -		return 0;
> -
>   	if (!chip->ops->request_locality)
>   		return 0;
>
> @@ -59,9 +56,6 @@ static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags)
>   {
>   	int rc;
>
> -	if (flags & TPM_TRANSMIT_NESTED)
> -		return;
> -
>   	if (!chip->ops->relinquish_locality)
>   		return;
>
> @@ -74,9 +68,6 @@ static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags)
>
>   static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)
>   {
> -	if (flags & TPM_TRANSMIT_NESTED)
> -		return 0;
> -
>   	if (!chip->ops->cmd_ready)
>   		return 0;
>
> @@ -85,9 +76,6 @@ static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)
>
>   static int tpm_go_idle(struct tpm_chip *chip, unsigned int flags)
>   {
> -	if (flags & TPM_TRANSMIT_NESTED)
> -		return 0;
> -
>   	if (!chip->ops->go_idle)
>   		return 0;
>
> @@ -169,7 +157,9 @@ int tpm_try_get_ops(struct tpm_chip *chip)
>   		goto out_lock;
>
>   	mutex_lock(&chip->tpm_mutex);
> -	return 0;
> +	rc = tpm_chip_start(chip, 0);
> +	if (rc)
> +		mutex_unlock(&chip->tpm_mutex);

This cannot be right to fall through to up_read() etc.


>   out_lock:
>   	up_read(&chip->ops_sem);
>   	put_device(&chip->dev);
> @@ -186,6 +176,7 @@ EXPORT_SYMBOL_GPL(tpm_try_get_ops);
>    */
>   void tpm_put_ops(struct tpm_chip *chip)
>   {
> +	tpm_chip_stop(chip, 0);
>   	mutex_unlock(&chip->tpm_mutex);
>   	up_read(&chip->ops_sem);
>   	put_device(&chip->dev);
> @@ -563,7 +554,11 @@ int tpm_chip_register(struct tpm_chip *chip)
>   {
>   	int rc;
>
> +	rc = tpm_chip_start(chip, 0);
> +	if (rc)
> +		return rc;
>   	rc = tpm_auto_startup(chip);
> +	tpm_chip_stop(chip, 0);
>   	if (rc)
>   		return rc;
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 2c79284ffd4e..21ac8da94d90 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -168,11 +168,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
>   	memcpy(save, buf, save_size);
>
>   	for (;;) {
> -		ret = tpm_chip_start(chip, flags);
> -		if (ret)
> -			return ret;
>   		ret = tpm_try_transmit(chip, buf, bufsiz, flags);
> -		tpm_chip_stop(chip, flags);
>   		if (ret < 0)
>   			break;
>   		rc = be32_to_cpu(header->return_code);
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index c42a75710b70..f9d56dfd0d20 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -485,15 +485,6 @@ extern const struct file_operations tpm_fops;
>   extern const struct file_operations tpmrm_fops;
>   extern struct idr dev_nums_idr;
>
> -/**
> - * enum tpm_transmit_flags - flags for tpm_transmit()
> - *
> - * %TPM_TRANSMIT_NESTED:	discard setup steps (power management, locality)
> - */
> -enum tpm_transmit_flags {
> -	TPM_TRANSMIT_NESTED      = BIT(0),
> -};
> -
>   ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
>   		     unsigned int flags);
>   ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,
> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> index ced1dc91ba6f..d913715d30aa 100644
> --- a/drivers/char/tpm/tpm2-space.c
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -60,7 +60,10 @@ int tpm2_init_space(struct tpm_space *space)
>   void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space)
>   {
>   	mutex_lock(&chip->tpm_mutex);
> -	tpm2_flush_sessions(chip, space);
> +	if (!tpm_chip_start(chip, 0)) {
> +		tpm2_flush_sessions(chip, space);
> +		tpm_chip_stop(chip, 0);
> +	}
>   	mutex_unlock(&chip->tpm_mutex);
>   	kfree(space->context_buf);
>   	kfree(space->session_buf);
> diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
> index e8a1da2810a9..a4bb60e163cc 100644
> --- a/drivers/char/tpm/tpm_vtpm_proxy.c
> +++ b/drivers/char/tpm/tpm_vtpm_proxy.c
> @@ -417,8 +417,7 @@ static int vtpm_proxy_request_locality(struct tpm_chip *chip, int locality)
>
>   	proxy_dev->state |= STATE_DRIVER_COMMAND;
>
> -	rc = tpm_transmit_cmd(chip, &buf, 0, TPM_TRANSMIT_NESTED,
> -			      "attempting to set locality");
> +	rc = tpm_transmit_cmd(chip, &buf, 0, 0, "attempting to set locality");
>
>   	proxy_dev->state &= ~STATE_DRIVER_COMMAND;
>