diff options
| author |   Benjamin Berg <benjamin.berg@intel.com> | 2024-12-17 21:49:06 +0100 |
|---|---|---|
| committer |   Johannes Berg <johannes.berg@intel.com> | 2025-01-10 13:50:00 +0100 |
| commit | 579e7fd383ff3f7a4f685489f8fe18cfd8659074 (patch) | |
| tree | feef61e31fb2de558cd7eb0427f20efacd31652e | |
| parent | um: Remove unused user_context function (diff) | |
| download | wireguard-linux-579e7fd383ff3f7a4f685489f8fe18cfd8659074.tar.xz wireguard-linux-579e7fd383ff3f7a4f685489f8fe18cfd8659074.zip | |
um: rtc: use RTC time when calculating the alarm
The kernel realtime and the current RTC time may have a (small) offset.
Should the kernel time be slightly in the future, then the timeout is
zero. This is problematic in time-travel mode, as a zero timeout can be
correctly configured and time never advances.
Replace the kernel realtime read with a read of the actual persistent
RTC clock. Also, for time-travel, calculate the exact nanoseconds needed
for the clock to advance.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Co-developed-by: Avraham Stern <avraham.stern@intel.com>
Link: https://patch.msgid.link/20241217204906.1408011-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to '')
| -rw-r--r-- | arch/um/drivers/rtc_kern.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/um/drivers/rtc_kern.c b/arch/um/drivers/rtc_kern.c index 134a58f93c85..9158c936c128 100644 --- a/arch/um/drivers/rtc_kern.c +++ b/arch/um/drivers/rtc_kern.c @@ -51,6 +51,7 @@ static int uml_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) static int uml_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) { + struct timespec64 ts; unsigned long long secs; if (!enable && !uml_rtc_alarm_enabled) @@ -58,7 +59,8 @@ static int uml_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) uml_rtc_alarm_enabled = enable; - secs = uml_rtc_alarm_time - ktime_get_real_seconds(); + read_persistent_clock64(&ts); + secs = uml_rtc_alarm_time - ts.tv_sec; if (time_travel_mode == TT_MODE_OFF) { if (!enable) { @@ -73,7 +75,8 @@ static int uml_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) if (enable) time_travel_add_event_rel(¨_rtc_alarm_event, - secs * NSEC_PER_SEC); + secs * NSEC_PER_SEC - + ts.tv_nsec); } return 0; |