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ptp: only allow phase values lower than 1 period

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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 <olteanv@gmail.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vladimir Oltean 2020-08-05 03:10:47 +03:00 committed by David S. Miller
parent 4c900a6b4e
commit c29f9aa350
1 changed files with 13 additions and 0 deletions
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13
drivers/ptp/ptp_chardev.c
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@ -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;