Re: [PATCH v9 16/19] tpm: Add ability to set the preferred locality the TPM chip uses

ross.philipson
2024-06-04T22:15:30Z

On 6/4/24 1:27 PM, Jarkko Sakkinen wrote:
> On Fri May 31, 2024 at 4:03 AM EEST, Ross Philipson wrote:
>> Curently the locality is hard coded to 0 but for DRTM support, access
>> is needed to localities 1 through 4.
>>
>> Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
>> ---
>> drivers/char/tpm/tpm-chip.c | 24 +++++++++++++++++++++++-
>> drivers/char/tpm/tpm-interface.c | 15 +++++++++++++++
>> drivers/char/tpm/tpm.h | 1 +
>> include/linux/tpm.h | 4 ++++
>> 4 files changed, 43 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
>> index 854546000c92..73eac54d61fb 100644
>> --- a/drivers/char/tpm/tpm-chip.c
>> +++ b/drivers/char/tpm/tpm-chip.c
>> @@ -44,7 +44,7 @@ static int tpm_request_locality(struct tpm_chip *chip)
>> if (!chip->ops->request_locality)
>> return 0;
>>
>> - rc = chip->ops->request_locality(chip, 0);
>> + rc = chip->ops->request_locality(chip, chip->pref_locality);
>> if (rc < 0)
>> return rc;
>>
>> @@ -143,6 +143,27 @@ void tpm_chip_stop(struct tpm_chip *chip)
>> }
>> EXPORT_SYMBOL_GPL(tpm_chip_stop);
>>
>> +/**
>> + * tpm_chip_preferred_locality() - set the TPM chip preferred locality to open
>> + * @chip: a TPM chip to use
>> + * @locality: the preferred locality
>> + *
>> + * Return:
>> + * * true - Preferred locality set
>> + * * false - Invalid locality specified
>> + */
>> +bool tpm_chip_preferred_locality(struct tpm_chip *chip, int locality)
>> +{
>> + if (locality < 0 || locality >=TPM_MAX_LOCALITY)
>> + return false;
>> +
>> + mutex_lock(&chip->tpm_mutex);
>> + chip->pref_locality = locality;
>> + mutex_unlock(&chip->tpm_mutex);
>> + return true;
>> +}
>> +EXPORT_SYMBOL_GPL(tpm_chip_preferred_locality);
>> +
>> /**
>> * tpm_try_get_ops() - Get a ref to the tpm_chip
>> * @chip: Chip to ref
>> @@ -374,6 +395,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
>> }
>>
>> chip->locality = -1;
>> + chip->pref_locality = 0;
>> return chip;
>>
>> out:
>> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
>> index 5da134f12c9a..35f14ccecf0e 100644
>> --- a/drivers/char/tpm/tpm-interface.c
>> +++ b/drivers/char/tpm/tpm-interface.c
>> @@ -274,6 +274,21 @@ int tpm_is_tpm2(struct tpm_chip *chip)
>> }
>> EXPORT_SYMBOL_GPL(tpm_is_tpm2);
>>
>> +/**
>> + * tpm_preferred_locality() - set the TPM chip preferred locality to open
>> + * @chip: a TPM chip to use
>> + * @locality: the preferred locality
>> + *
>> + * Return:
>> + * * true - Preferred locality set
>> + * * false - Invalid locality specified
>> + */
>> +bool tpm_preferred_locality(struct tpm_chip *chip, int locality)
>> +{
>> + return tpm_chip_preferred_locality(chip, locality);
>> +}
>> +EXPORT_SYMBOL_GPL(tpm_preferred_locality);
>
> What good does this extra wrapping do?
>
> tpm_set_default_locality() and default_locality would make so much more
> sense in any case.

Are you mainly just talking about my naming choices here and in the
follow-on response? Can you clarify what you are requesting?

Thanks
Ross

>
> BR, Jarkko