From 7084eddf6be94e73f8298c1a28078b91536f2975 Mon Sep 17 00:00:00 2001 From: Jerry Snitselaar Date: Wed, 30 Oct 2019 15:58:43 -0700 Subject: [PATCH] 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 Cc: Mimi Zohar Cc: Peter Huewe Cc: Jason Gunthorpe Cc: linux-integrity@vger.kernel.org Signed-off-by: Jerry Snitselaar Reviewed-by: Mimi Zohar Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- 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 2881626..58e94e7 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/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 diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c index 3b53b3e..d52bf4d 100644 --- a/drivers/char/tpm/tpm-sysfs.c +++ b/drivers/char/tpm/tpm-sysfs.c @@ -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; } -- 2.7.4