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.
Also add an entry to Documentation/ABI/stable/sysfs-class-tpm
describing the new file.
Cc: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Cc: Peter Huewe <peterhuewe@xxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: linux-integrity@xxxxxxxxxxxxxxx
Signed-off-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
---
v3: - Change file name to version_major.
v2: - Fix TCG usage in commit message.
- Add entry to sysfs-class-tpm in Documentation/ABI/stable
Documentation/ABI/stable/sysfs-class-tpm | 11 ++++++++
drivers/char/tpm/tpm-sysfs.c | 34 +++++++++++++++++++-----
2 files changed, 38 insertions(+), 7 deletions(-)
diff --git a/Documentation/ABI/stable/sysfs-class-tpm b/Documentation/ABI/stable/sysfs-class-tpm
index c0e23830f56a..116f8d3a8ddc 100644
--- a/Documentation/ABI/stable/sysfs-class-tpm
+++ b/Documentation/ABI/stable/sysfs-class-tpm
@@ -183,3 +183,14 @@ Description: The "timeouts" property shows the 4 vendor-specific values
The four timeout values are shown in usecs, with a trailing
"[original]" or "[adjusted]" depending on whether the values
were scaled by the driver to be reported in usec from msecs.
+
+What: /sys/class/tpm/tpmX/version_major
+Date: October 2019
+KernelVersion: 5.5
+Contact: linux-integrity@xxxxxxxxxxxxxxx
+Description: The "version_major" property shows the TCG spec version
+ implemented by the TPM device.
+
+ Example output:
+
+ 2.0
diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index edfa89160010..6993ef00f256 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, struct device_attribute *attr,
}
static DEVICE_ATTR_RO(timeouts);
-static struct attribute *tpm_dev_attrs[] = {
+static ssize_t version_major_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct tpm_chip *chip = to_tpm_chip(dev);
+
+ return sprintf(buf, "%s\n", chip->flags & TPM_CHIP_FLAG_TPM2
+ ? "2.0" : "1.2");
+}
+static DEVICE_ATTR_RO(version_major);
+
+static struct attribute *tpm12_dev_attrs[] = {
&dev_attr_pubek.attr,
&dev_attr_pcrs.attr,
&dev_attr_enabled.attr,
@@ -320,18 +330,28 @@ static struct attribute *tpm_dev_attrs[] = {
&dev_attr_cancel.attr,
&dev_attr_durations.attr,
&dev_attr_timeouts.attr,
+ &dev_attr_version_major.attr,
NULL,
};
-static const struct attribute_group tpm_dev_group = {
- .attrs = tpm_dev_attrs,
+static struct attribute *tpm20_dev_attrs[] = {
+ &dev_attr_version_major.attr,
+ NULL
+};
+
+static const struct attribute_group tpm12_dev_group = {
+ .attrs = tpm12_dev_attrs,
+};
+
+static const struct attribute_group tpm20_dev_group = {
+ .attrs = tpm20_dev_attrs,
};
void tpm_sysfs_add_device(struct tpm_chip *chip)
{
- if (chip->flags & TPM_CHIP_FLAG_TPM2)
- return;
-
WARN_ON(chip->groups_cnt != 0);
- chip->groups[chip->groups_cnt++] = &tpm_dev_group;
+ if (chip->flags & TPM_CHIP_FLAG_TPM2)
+ chip->groups[chip->groups_cnt++] = &tpm20_dev_group;
+ else
+ chip->groups[chip->groups_cnt++] = &tpm12_dev_group;
}
--
2.23.0
