On Fri, 2019-10-25 at 07:28 -0700, Jerry Snitselaar wrote:
> 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.
Use "TCG" uppercase consistently.
>
> 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>
thanks!
Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
FYI, on my system(s) the new file is accessible as
/sys/class/tpm/tpm0/version_major. Does this need to be documented
anywhere?
> ---
> 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, struct device_attribute *attr,
> }
> static DEVICE_ATTR_RO(timeouts);
>
> -static struct attribute *tpm_dev_attrs[] = {
> +static ssize_t major_version_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(major_version);
> +
> +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_major_version.attr,
> NULL,
> };
>
> -static const struct attribute_group tpm_dev_group = {
> - .attrs = tpm_dev_attrs,
> +static struct attribute *tpm20_dev_attrs[] = {
> + &dev_attr_major_version.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;
> }
