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Message-ID: <alpine.DEB.2.21.1810232143020.3433@jsakkine-mobl1>
Date:   Tue, 23 Oct 2018 21:43:17 +0300 (EEST)
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Tomas Winkler <tomas.winkler@...el.com>
cc:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Nayna Jain <nayna@...ux.vnet.ibm.com>,
        Alexander Usyskin <alexander.usyskin@...el.com>,
        Tadeusz Struk <tadeusz.struk@...el.com>,
        linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 11/21] tpm: factor out tpm 1.x pm suspend flow into
 tpm1-cmd.c

On Fri, 19 Oct 2018, Tomas Winkler wrote:
> Factor out TPM 1.x suspend flow from tpm-interface.c into a new function
> tpm1_pm_suspend() in tpm1-cmd.c
>
> Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> ---
> V2-V3: Rebase.
> V4: 1. Add kdoc for tpm1_pm_suspend().
>    2. Fix commit message.
> V5: Adjust the kdoc to the new standard.
> V6: Rebase.
> V7: Resend.
>
> drivers/char/tpm/tpm-interface.c | 55 ++++--------------------------------
> drivers/char/tpm/tpm.h           |  2 ++
> drivers/char/tpm/tpm1-cmd.c      | 61 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 68 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 43d3540a7875..e7f220f691f9 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -586,15 +586,6 @@ int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
> }
> EXPORT_SYMBOL_GPL(tpm_send);
>
> -#define TPM_ORD_SAVESTATE 152
> -#define SAVESTATE_RESULT_SIZE 10
> -
> -static const struct tpm_input_header savestate_header = {
> -	.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
> -	.length = cpu_to_be32(10),
> -	.ordinal = cpu_to_be32(TPM_ORD_SAVESTATE)
> -};
> -
> /*
>  * We are about to suspend. Save the TPM state
>  * so that it can be restored.
> @@ -602,54 +593,18 @@ static const struct tpm_input_header savestate_header = {
> int tpm_pm_suspend(struct device *dev)
> {
> 	struct tpm_chip *chip = dev_get_drvdata(dev);
> -	struct tpm_cmd_t cmd;
> -	int rc, try;
> -
> -	u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };
> +	int rc = 0;
>
> -	if (chip == NULL)
> +	if (!chip)
> 		return -ENODEV;
>
> 	if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)
> 		return 0;
>
> -	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> +	if (chip->flags & TPM_CHIP_FLAG_TPM2)
> 		tpm2_shutdown(chip, TPM2_SU_STATE);
> -		return 0;
> -	}
> -
> -	/* for buggy tpm, flush pcrs with extend to selected dummy */
> -	if (tpm_suspend_pcr)
> -		rc = tpm1_pcr_extend(chip, tpm_suspend_pcr, dummy_hash,
> -				     "extending dummy pcr before suspend");
> -
> -	/* now do the actual savestate */
> -	for (try = 0; try < TPM_RETRY; try++) {
> -		cmd.header.in = savestate_header;
> -		rc = tpm_transmit_cmd(chip, NULL, &cmd, SAVESTATE_RESULT_SIZE,
> -				      0, 0, NULL);
> -
> -		/*
> -		 * If the TPM indicates that it is too busy to respond to
> -		 * this command then retry before giving up.  It can take
> -		 * several seconds for this TPM to be ready.
> -		 *
> -		 * This can happen if the TPM has already been sent the
> -		 * SaveState command before the driver has loaded.  TCG 1.2
> -		 * specification states that any communication after SaveState
> -		 * may cause the TPM to invalidate previously saved state.
> -		 */
> -		if (rc != TPM_WARN_RETRY)
> -			break;
> -		tpm_msleep(TPM_TIMEOUT_RETRY);
> -	}
> -
> -	if (rc)
> -		dev_err(&chip->dev,
> -			"Error (%d) sending savestate before suspend\n", rc);
> -	else if (try > 0)
> -		dev_warn(&chip->dev, "TPM savestate took %dms\n",
> -			 try * TPM_TIMEOUT_RETRY);
> +	else
> +		rc = tpm1_pm_suspend(chip, tpm_suspend_pcr);
>
> 	return rc;
> }
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index f284a98a9455..754f7bcb15fa 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -542,6 +542,8 @@ ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
> 			 const char *desc);
> int tpm_startup(struct tpm_chip *chip);
> int tpm_get_timeouts(struct tpm_chip *);
> +
> +int tpm1_pm_suspend(struct tpm_chip *chip, int tpm_suspend_pcr);
> int tpm1_auto_startup(struct tpm_chip *chip);
> int tpm1_do_selftest(struct tpm_chip *chip);
> int tpm1_get_timeouts(struct tpm_chip *chip);
> diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
> index a69a02366c32..3bd9f1fa77ce 100644
> --- a/drivers/char/tpm/tpm1-cmd.c
> +++ b/drivers/char/tpm/tpm1-cmd.c
> @@ -666,3 +666,64 @@ int tpm1_auto_startup(struct tpm_chip *chip)
> 		rc = -ENODEV;
> 	return rc;
> }
> +
> +#define TPM_ORD_SAVESTATE 152
> +#define SAVESTATE_RESULT_SIZE 10
> +static const struct tpm_input_header savestate_header = {
> +	.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
> +	.length = cpu_to_be32(10),
> +	.ordinal = cpu_to_be32(TPM_ORD_SAVESTATE)
> +};
> +
> +/**
> + * tpm1_pm_suspend() - pm suspend handler
> + * @chip: TPM chip to use.
> + * @tpm_suspend_pcr: flush pcr for buggy TPM chips.
> + *
> + * The functions saves the TPM state to be restored on resume.
> + *
> + * Return:
> + * * 0 on success,
> + * * < 0 on error.
> + */
> +int tpm1_pm_suspend(struct tpm_chip *chip, int tpm_suspend_pcr)
> +{
> +	u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };
> +	struct tpm_cmd_t cmd;
> +	int rc, try;
> +
> +	/* for buggy tpm, flush pcrs with extend to selected dummy */
> +	if (tpm_suspend_pcr)
> +		rc = tpm1_pcr_extend(chip, tpm_suspend_pcr, dummy_hash,
> +				     "extending dummy pcr before suspend");
> +
> +	/* now do the actual savestate */
> +	for (try = 0; try < TPM_RETRY; try++) {
> +		cmd.header.in = savestate_header;
> +		rc = tpm_transmit_cmd(chip, NULL, &cmd, SAVESTATE_RESULT_SIZE,
> +				      0, 0, NULL);
> +
> +		/*
> +		 * If the TPM indicates that it is too busy to respond to
> +		 * this command then retry before giving up.  It can take
> +		 * several seconds for this TPM to be ready.
> +		 *
> +		 * This can happen if the TPM has already been sent the
> +		 * SaveState command before the driver has loaded.  TCG 1.2
> +		 * specification states that any communication after SaveState
> +		 * may cause the TPM to invalidate previously saved state.
> +		 */
> +		if (rc != TPM_WARN_RETRY)
> +			break;
> +		tpm_msleep(TPM_TIMEOUT_RETRY);
> +	}
> +
> +	if (rc)
> +		dev_err(&chip->dev, "Error (%d) sending savestate before suspend\n",
> +			rc);
> +	else if (try > 0)
> +		dev_warn(&chip->dev, "TPM savestate took %dms\n",
> +			 try * TPM_TIMEOUT_RETRY);
> +
> +	return rc;
> +}
>

Tested-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>

/Jarkko

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