[RFC PATCH v2 2/2] tpm: show the default locality in sysfs

[Jarkko Sakkinen <jarkko@kernel.org>]

From: Ross Philipson <ross.philipson@oracle.com>

Expose the default locality as read-only attribute through sysfs.

Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v2:
- A new patch.
- Import from the original Trenchboot patch set.
- Drop the store operation.
- Tested with https://codeberg.org/jarkko/tpm-set-locality-test/src/branch/main/src/main.rs
---
 drivers/char/tpm/tpm-sysfs.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index 94231f052ea7..4f5e60b1e4c9 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -309,6 +309,14 @@ static ssize_t tpm_version_major_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(tpm_version_major);
 
+static ssize_t locality_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct tpm_chip *chip = to_tpm_chip(dev);
+
+	return sprintf(buf, "%d\n", chip->default_locality);
+}
+static DEVICE_ATTR_RO(locality);
+
 #ifdef CONFIG_TCG_TPM2_HMAC
 static ssize_t null_name_show(struct device *dev, struct device_attribute *attr,
 			      char *buf)
@@ -336,6 +344,7 @@ static struct attribute *tpm1_dev_attrs[] = {
 	&dev_attr_durations.attr,
 	&dev_attr_timeouts.attr,
 	&dev_attr_tpm_version_major.attr,
+	&dev_attr_locality.attr,
 	NULL,
 };
 
@@ -344,6 +353,7 @@ static struct attribute *tpm2_dev_attrs[] = {
 #ifdef CONFIG_TCG_TPM2_HMAC
 	&dev_attr_null_name.attr,
 #endif
+	&dev_attr_locality.attr,
 	NULL
 };
 
-- 
2.47.0