Commit e0d21901 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI: TAD: RTC: Refine timer value computations and checks 



Since rtc_tm_to_ktime() may overflow for large RTC time values and
full second granularity is sufficient in timer value computations
in acpi_tad_rtc_set_alarm() and acpi_tad_rtc_read_alarm(), use
rtc_tm_to_time64() instead of that function, which also allows the
computations to be simplified.

Moreover, U32_MAX is a special "timer disabled" value, so make
acpi_tad_rtc_set_alarm() reject it when attempting to program the
alarm timers.

Fixes: 7572dcab ("ACPI: TAD: Add alarm support to the RTC class device interface")
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://patch.msgid.link/3414608.aeNJFYEL58@rafael.j.wysocki
parent 77dd14ab

drivers/acpi/acpi_tad.c

+3 −5
Original line number Diff line number Diff line
@@ -680,9 +680,8 @@ static int acpi_tad_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t) 


		acpi_tad_rt_to_tm(&rt, &tm_now);



		value = ktime_divns(ktime_sub(rtc_tm_to_ktime(t->time),

					      rtc_tm_to_ktime(tm_now)), NSEC_PER_SEC);

		if (value <= 0 || value > U32_MAX)

		value = rtc_tm_to_time64(&t->time) - rtc_tm_to_time64(&tm_now);

		if (value <= 0 || value >= U32_MAX)

			return -EINVAL;

	}
@@ -745,8 +744,7 @@ static int acpi_tad_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t) 


	if (retval != ACPI_TAD_WAKE_DISABLED) {

		t->enabled = 1;

		t->time = rtc_ktime_to_tm(ktime_add_ns(rtc_tm_to_ktime(tm_now),

						       (u64)retval * NSEC_PER_SEC));

		rtc_time64_to_tm(rtc_tm_to_time64(&tm_now) + retval, &t->time);

	} else {

		t->enabled = 0;

		t->time = tm_now;