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tpm: Add tpm_version_major sysfs file

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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 major 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@linux.intel.com>
Cc: Mimi Zohar <zohar@linux.ibm.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>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
This commit is contained in:
Jerry Snitselaar 2019-10-30 15:58:43 -07:00 committed by Jarkko Sakkinen
parent c269e876c5
commit 7084eddf6b
2 changed files with 38 additions and 7 deletions
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11
Documentation/ABI/stable/sysfs-class-tpm
View file

@ -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/tpm_version_major
Date: October 2019
KernelVersion: 5.5
Contact: linux-integrity@vger.kernel.org
Description: The "tpm_version_major" property shows the TCG spec major version
implemented by the TPM device.
Example output:
2

34
drivers/char/tpm/tpm-sysfs.c
View file

@ -310,7 +310,17 @@ 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 tpm_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" : "1");
}
static DEVICE_ATTR_RO(tpm_version_major);
static struct attribute *tpm1_dev_attrs[] = {
&dev_attr_pubek.attr,
&dev_attr_pcrs.attr,
&dev_attr_enabled.attr,
@ -321,18 +331,28 @@ static struct attribute *tpm_dev_attrs[] = {
&dev_attr_cancel.attr,
&dev_attr_durations.attr,
&dev_attr_timeouts.attr,
&dev_attr_tpm_version_major.attr,
NULL,
};
static const struct attribute_group tpm_dev_group = {
.attrs = tpm_dev_attrs,
static struct attribute *tpm2_dev_attrs[] = {
&dev_attr_tpm_version_major.attr,
NULL
};
static const struct attribute_group tpm1_dev_group = {
.attrs = tpm1_dev_attrs,
};
static const struct attribute_group tpm2_dev_group = {
.attrs = tpm2_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++] = &tpm2_dev_group;
else
chip->groups[chip->groups_cnt++] = &tpm1_dev_group;
}