Commit 4eca49d0 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

timekeeping: Prepare do_adtimex() for auxiliary clocks 



Exclude ADJ_TAI, leap seconds and PPS functionality as they make no sense
in the context of auxiliary clocks and provide a time stamp based on the
actual clock.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarJohn Stultz <jstultz@google.com>
Link: https://lore.kernel.org/all/20250625183758.253203783@linutronix.de
parent 775f71eb

kernel/time/timekeeping.c

+33 −3
Original line number Diff line number Diff line
@@ -58,6 +58,17 @@ static struct tk_data timekeeper_data[TIMEKEEPERS_MAX]; 
/* The core timekeeper */

#define tk_core		(timekeeper_data[TIMEKEEPER_CORE])



#ifdef CONFIG_POSIX_AUX_CLOCKS

static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)

{

	return ktime_get_aux_ts64(CLOCK_AUX + tkid - TIMEKEEPER_AUX_FIRST, ts);

}

#else

static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)

{

	return false;

}

#endif



/* flag for if timekeeping is suspended */

int __read_mostly timekeeping_suspended;
@@ -2508,7 +2519,7 @@ ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real, 
/*

 * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex

 */

static int timekeeping_validate_timex(const struct __kernel_timex *txc)

static int timekeeping_validate_timex(const struct __kernel_timex *txc, bool aux_clock)

{

	if (txc->modes & ADJ_ADJTIME) {

		/* singleshot must not be used with any other mode bits */
@@ -2567,6 +2578,20 @@ static int timekeeping_validate_timex(const struct __kernel_timex *txc) 
			return -EINVAL;

	}



	if (aux_clock) {

		/* Auxiliary clocks are similar to TAI and do not have leap seconds */

		if (txc->status & (STA_INS | STA_DEL))

			return -EINVAL;



		/* No TAI offset setting */

		if (txc->modes & ADJ_TAI)

			return -EINVAL;



		/* No PPS support either */

		if (txc->status & (STA_PPSFREQ | STA_PPSTIME))

			return -EINVAL;

	}



	return 0;

}
@@ -2595,17 +2620,22 @@ static int __do_adjtimex(struct tk_data *tkd, struct __kernel_timex *txc, 
			 struct adjtimex_result *result)

{

	struct timekeeper *tks = &tkd->shadow_timekeeper;

	bool aux_clock = !timekeeper_is_core_tk(tks);

	struct timespec64 ts;

	s32 orig_tai, tai;

	int ret;



	/* Validate the data before disabling interrupts */

	ret = timekeeping_validate_timex(txc);

	ret = timekeeping_validate_timex(txc, aux_clock);

	if (ret)

		return ret;

	add_device_randomness(txc, sizeof(*txc));



	if (!aux_clock)

		ktime_get_real_ts64(&ts);

	else

		tk_get_aux_ts64(tkd->timekeeper.id, &ts);



	add_device_randomness(&ts, sizeof(ts));



	guard(raw_spinlock_irqsave)(&tkd->lock);