diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index a34ac069335f..7404d3831527 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -564,117 +564,52 @@ static inline bool rtc_tv_nsec_ok(unsigned long set_offset_nsec, return false; } -#ifdef CONFIG_RTC_SYSTOHC -/* - * rtc_set_ntp_time - Save NTP synchronized time to the RTC - */ -static int rtc_set_ntp_time(struct timespec64 now, unsigned long *offset_nsec) -{ - struct timespec64 to_set; - struct rtc_device *rtc; - struct rtc_time tm; - int err = -ENODEV; - bool ok; - - rtc = rtc_class_open(CONFIG_RTC_SYSTOHC_DEVICE); - if (!rtc) - goto out_err; - - if (!rtc->ops || !rtc->ops->set_time) - goto out_close; - - /* Store the update offset for this RTC */ - *offset_nsec = rtc->set_offset_nsec; - - ok = rtc_tv_nsec_ok(rtc->set_offset_nsec, &to_set, &now); - if (!ok) { - err = -EPROTO; - goto out_close; - } - - rtc_time64_to_tm(to_set.tv_sec, &tm); - - err = rtc_set_time(rtc, &tm); - -out_close: - rtc_class_close(rtc); -out_err: - return err; -} - -static void sync_rtc_clock(void) -{ - unsigned long offset_nsec; - struct timespec64 adjust; - int rc; - - ktime_get_real_ts64(&adjust); - - if (persistent_clock_is_local) - adjust.tv_sec -= (sys_tz.tz_minuteswest * 60); - - /* - * The current RTC in use will provide the nanoseconds offset prior - * to a full second it wants to be called at, and invokes - * rtc_tv_nsec_ok() internally. - */ - rc = rtc_set_ntp_time(adjust, &offset_nsec); - if (rc == -ENODEV) - return; - - sched_sync_hw_clock(offset_nsec, rc != 0); -} -#else -static inline void sync_rtc_clock(void) { } -#endif - #ifdef CONFIG_GENERIC_CMOS_UPDATE int __weak update_persistent_clock64(struct timespec64 now64) { return -ENODEV; } +#else +static inline int update_persistent_clock64(struct timespec64 now64) +{ + return -ENODEV; +} #endif -static bool sync_cmos_clock(void) +#ifdef CONFIG_RTC_SYSTOHC +/* Save NTP synchronized time to the RTC */ +static int update_rtc(struct timespec64 *to_set, unsigned long *offset_nsec) { - static bool no_cmos; - struct timespec64 now; - struct timespec64 adjust; - int rc = -EPROTO; - long target_nsec = NSEC_PER_SEC / 2; + struct rtc_device *rtc; + struct rtc_time tm; + int err = -ENODEV; - if (!IS_ENABLED(CONFIG_GENERIC_CMOS_UPDATE)) - return false; + rtc = rtc_class_open(CONFIG_RTC_SYSTOHC_DEVICE); + if (!rtc) + return -ENODEV; - if (no_cmos) - return false; + if (!rtc->ops || !rtc->ops->set_time) + goto out_close; - /* - * Historically update_persistent_clock64() has followed x86 - * semantics, which match the MC146818A/etc RTC. This RTC will store - * 'adjust' and then in .5s it will advance once second. - * - * Architectures are strongly encouraged to use rtclib and not - * implement this legacy API. - */ - ktime_get_real_ts64(&now); - if (rtc_tv_nsec_ok(target_nsec, &adjust, &now)) { - if (persistent_clock_is_local) - adjust.tv_sec -= (sys_tz.tz_minuteswest * 60); - rc = update_persistent_clock64(adjust); - /* - * The machine does not support update_persistent_clock64 even - * though it defines CONFIG_GENERIC_CMOS_UPDATE. - */ - if (rc == -ENODEV) { - no_cmos = true; - return false; - } + /* First call might not have the correct offset */ + if (*offset_nsec == rtc->set_offset_nsec) { + rtc_time64_to_tm(to_set->tv_sec, &tm); + err = rtc_set_time(rtc, &tm); + } else { + /* Store the update offset and let the caller try again */ + *offset_nsec = rtc->set_offset_nsec; + err = -EAGAIN; } - - sched_sync_hw_clock(target_nsec, rc != 0); - return true; +out_close: + rtc_class_close(rtc); + return err; } +#else +static inline int update_rtc(struct timespec64 *to_set, unsigned long *offset_nsec) +{ + return -ENODEV; +} +#endif /* * If we have an externally synchronized Linux clock, then update RTC clock @@ -686,6 +621,15 @@ static bool sync_cmos_clock(void) */ static void sync_hw_clock(struct work_struct *work) { + /* + * The default synchronization offset is 500ms for the deprecated + * update_persistent_clock64() under the assumption that it uses + * the infamous CMOS clock (MC146818). + */ + static unsigned long offset_nsec = NSEC_PER_SEC / 2; + struct timespec64 now, to_set; + int res = -EAGAIN; + /* * Don't update if STA_UNSYNC is set and if ntp_notify_cmos_timer() * managed to schedule the work between the timer firing and the @@ -694,10 +638,26 @@ static void sync_hw_clock(struct work_struct *work) if (!ntp_synced() || hrtimer_is_queued(&sync_hrtimer)) return; - if (sync_cmos_clock()) - return; + ktime_get_real_ts64(&now); + /* If @now is not in the allowed window, try again */ + if (!rtc_tv_nsec_ok(offset_nsec, &to_set, &now)) + goto rearm; - sync_rtc_clock(); + /* Take timezone adjusted RTCs into account */ + if (persistent_clock_is_local) + to_set.tv_sec -= (sys_tz.tz_minuteswest * 60); + + /* Try the legacy RTC first. */ + res = update_persistent_clock64(to_set); + if (res != -ENODEV) + goto rearm; + + /* Try the RTC class */ + res = update_rtc(&to_set, &offset_nsec); + if (res == -ENODEV) + return; +rearm: + sched_sync_hw_clock(offset_nsec, res != 0); } void ntp_notify_cmos_timer(void)