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From:   Jerry Snitselaar <jsnitsel@redhat.com>
To:     linux-kernel@vger.kernel.org
Cc:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Peter Huewe <peterhuewe@gmx.de>,
        Jason Gunthorpe <jgg@ziepe.ca>, linux-integrity@vger.kernel.org
Subject: [PATCH] tpm: Add major_version sysfs file
Date:   Fri, 25 Oct 2019 07:28:47 -0700
Message-Id: <20191025142847.14931-1-jsnitsel@redhat.com>
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Sender: linux-kernel-owner@vger.kernel.org
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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.

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>
---
 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, struc=
t device_attribute *attr,
 }
 static DEVICE_ATTR_RO(timeouts);
=20
-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,
 };
=20
-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,
 };
=20
 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;
 }
--=20
2.23.0