Commit 7084eddf authored by Jerry Snitselaar's avatar Jerry Snitselaar Committed by Jarkko Sakkinen
Browse files

tpm: Add tpm_version_major sysfs file 



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: default avatarJerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: default avatarMimi Zohar <zohar@linux.ibm.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent c269e876

Documentation/ABI/stable/sysfs-class-tpm

+11 −0
Original line number Diff line number Diff line
@@ -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

drivers/char/tpm/tpm-sysfs.c

+27 −7
Original line number Diff line number Diff line
@@ -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;

}