[PATCH] hwmon: (xgene) restrict power measurements to admin by default

[D Scott Phillips <scott@os.amperecomputing.com>]

Access to power information can be used to infer the instructions being run
and possibly even data being processed on a cpu[1]. Restrict access to
power information to administrator users by default. (Cf. a similar
powercap change[2].)

[1]: Lipp, Moritz, et al. "PLATYPUS: software-based power side-channel
     attacks on x86." 2021 IEEE Symposium on Security and Privacy (SP).
     IEEE, 2021.
[2]: commit 949dd0104c49 ("powercap: restrict energy meter to root access")

Fixes: ed42cfa881e1 ("hwmon: Add xgene hwmon driver")
Signed-off-by: D Scott Phillips <scott@os.amperecomputing.com>
Cc: stable@vger.kernel.org
---
 drivers/hwmon/xgene-hwmon.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/xgene-hwmon.c b/drivers/hwmon/xgene-hwmon.c
index 5cde837bfd09..6ad1daf2d354 100644
--- a/drivers/hwmon/xgene-hwmon.c
+++ b/drivers/hwmon/xgene-hwmon.c
@@ -397,9 +397,9 @@ static DEVICE_ATTR_RO(temp1_label);
 static DEVICE_ATTR_RO(temp1_input);
 static DEVICE_ATTR_RO(temp1_critical_alarm);
 static DEVICE_ATTR_RO(power1_label);
-static DEVICE_ATTR_RO(power1_input);
+static DEVICE_ATTR_ADMIN_RO(power1_input);
 static DEVICE_ATTR_RO(power2_label);
-static DEVICE_ATTR_RO(power2_input);
+static DEVICE_ATTR_ADMIN_RO(power2_input);
 
 static struct attribute *xgene_hwmon_attrs[] = {
 	&dev_attr_temp1_label.attr,
-- 
2.35.1