The way we define the phase (the difference between the time of the
signal's rising edge, and the closest integer multiple of the period),
it doesn't make sense to have a phase value equal or larger than 1
period.
So deny these settings coming from the user.
Signed-off-by: Vladimir Oltean <olte...@gmail.com>
---
Changes in v3:
Adjust the comments to cover the equality case.
Changes in v2:
Be sure to also deny the case where the period is equal to the phase.
This represents a 360 degree offset, which is equivalent to a phase of
zero, so it should be rejected on the grounds of having a modulo
equivalent as well.
drivers/ptp/ptp_chardev.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index e0e6f85966e1..af3bc65c4595 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -218,6 +218,19 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd,
unsigned long arg)
break;
}
}
+ if (perout->flags & PTP_PEROUT_PHASE) {
+ /*
+ * The phase should be specified modulo the
+ * period, therefore anything equal or larger
+ * than 1 period is invalid.
+ */
+ if (perout->phase.sec > perout->period.sec ||
+ (perout->phase.sec == perout->period.sec &&
+ perout->phase.nsec >=
perout->period.nsec)) {
+ err = -ERANGE;
+ break;
+ }
+ }
} else if (cmd == PTP_PEROUT_REQUEST) {
req.perout.flags &= PTP_PEROUT_V1_VALID_FLAGS;
req.perout.rsv[0] = 0;
--
2.25.1
