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Date:   Fri, 25 Oct 2019 11:45:22 -0700
From:   Jerry Snitselaar <jsnitsel@redhat.com>
To:     Mimi Zohar <zohar@linux.ibm.com>
Cc:     linux-kernel@vger.kernel.org,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Peter Huewe <peterhuewe@gmx.de>,
        Jason Gunthorpe <jgg@ziepe.ca>, linux-integrity@vger.kernel.org
Subject: Re: [PATCH] tpm: Add major_version sysfs file
Message-ID: <20191025184522.5txabdikcrn2dgvj@cantor>
Reply-To: Jerry Snitselaar <jsnitsel@redhat.com>
Mail-Followup-To: Mimi Zohar <zohar@linux.ibm.com>,
        linux-kernel@vger.kernel.org,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
        linux-integrity@vger.kernel.org
References: <20191025142847.14931-1-jsnitsel@redhat.com>
 <1572027516.4532.41.camel@linux.ibm.com>
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On Fri Oct 25 19, Mimi Zohar wrote:
>On Fri, 2019-10-25 at 07:28 -0700, Jerry Snitselaar wrote:
>> Easily determining what TCG version a tpm device implements
>> has been a pain point for userspace for a long time, so
>> add a sysfs file to report the tcg version of a tpm device.
>
>Use "TCG" uppercase consistently.
>=A0
>>
>> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>> Cc: Peter Huewe <peterhuewe@gmx.de>
>> Cc: Jason Gunthorpe <jgg@ziepe.ca>
>> Cc: linux-integrity@vger.kernel.org
>> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
>
>thanks!
>
>Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
>
>FYI, on my system(s) the new file is accessible as
>/sys/class/tpm/tpm0/version_major. =A0Does this need to be documented
>anywhere?
>
>

Yes, there should be an entry added to
Documentation/ABI/stable/sysfs-class-tpm.
I will fix that up and the TCG not being uppercase in a v2.

Should Documentation/ABI/stable/sysfs-class-tpm updated in
some way to reflect that those are all links under device
now and not actually there.

>> ---
>>  drivers/char/tpm/tpm-sysfs.c | 34 +++++++++++++++++++++++++++-------
>>  1 file changed, 27 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
>> index edfa89160010..9372c2d6f0b3 100644
>> --- a/drivers/char/tpm/tpm-sysfs.c
>> +++ b/drivers/char/tpm/tpm-sysfs.c
>> @@ -309,7 +309,17 @@ static ssize_t timeouts_show(struct device *dev, st=
ruct device_attribute *attr,
>>  }
>>  static DEVICE_ATTR_RO(timeouts);
>>
>> -static struct attribute *tpm_dev_attrs[] =3D {
>> +static ssize_t major_version_show(struct device *dev,
>> +=09=09=09=09  struct device_attribute *attr, char *buf)
>> +{
>> +=09struct tpm_chip *chip =3D to_tpm_chip(dev);
>> +
>> +=09return sprintf(buf, "%s\n", chip->flags & TPM_CHIP_FLAG_TPM2
>> +=09=09       ? "2.0" : "1.2");
>> +}
>> +static DEVICE_ATTR_RO(major_version);
>> +
>> +static struct attribute *tpm12_dev_attrs[] =3D {
>>  =09&dev_attr_pubek.attr,
>>  =09&dev_attr_pcrs.attr,
>>  =09&dev_attr_enabled.attr,
>> @@ -320,18 +330,28 @@ static struct attribute *tpm_dev_attrs[] =3D {
>>  =09&dev_attr_cancel.attr,
>>  =09&dev_attr_durations.attr,
>>  =09&dev_attr_timeouts.attr,
>> +=09&dev_attr_major_version.attr,
>>  =09NULL,
>>  };
>>
>> -static const struct attribute_group tpm_dev_group =3D {
>> -=09.attrs =3D tpm_dev_attrs,
>> +static struct attribute *tpm20_dev_attrs[] =3D {
>> +=09&dev_attr_major_version.attr,
>> +=09NULL
>> +};
>> +
>> +static const struct attribute_group tpm12_dev_group =3D {
>> +=09.attrs =3D tpm12_dev_attrs,
>> +};
>> +
>> +static const struct attribute_group tpm20_dev_group =3D {
>> +=09.attrs =3D tpm20_dev_attrs,
>>  };
>>
>>  void tpm_sysfs_add_device(struct tpm_chip *chip)
>>  {
>> -=09if (chip->flags & TPM_CHIP_FLAG_TPM2)
>> -=09=09return;
>> -
>>  =09WARN_ON(chip->groups_cnt !=3D 0);
>> -=09chip->groups[chip->groups_cnt++] =3D &tpm_dev_group;
>> +=09if (chip->flags & TPM_CHIP_FLAG_TPM2)
>> +=09=09chip->groups[chip->groups_cnt++] =3D &tpm20_dev_group;
>> +=09else
>> +=09=09chip->groups[chip->groups_cnt++] =3D &tpm12_dev_group;
>>  }
>