diff options
| -rw-r--r-- | include/linux/pvclock_gtod.h | 9 | ||||
| -rw-r--r-- | kernel/time/timekeeping.c | 50 |
2 files changed, 59 insertions, 0 deletions
diff --git a/include/linux/pvclock_gtod.h b/include/linux/pvclock_gtod.h new file mode 100644 index 00000000000..0ca75825b60 --- /dev/null +++ b/include/linux/pvclock_gtod.h @@ -0,0 +1,9 @@ +#ifndef _PVCLOCK_GTOD_H +#define _PVCLOCK_GTOD_H + +#include <linux/notifier.h> + +extern int pvclock_gtod_register_notifier(struct notifier_block *nb); +extern int pvclock_gtod_unregister_notifier(struct notifier_block *nb); + +#endif /* _PVCLOCK_GTOD_H */ diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index e424970bb56..69f5342e8d1 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -21,6 +21,7 @@ #include <linux/time.h> #include <linux/tick.h> #include <linux/stop_machine.h> +#include <linux/pvclock_gtod.h> static struct timekeeper timekeeper; @@ -180,6 +181,54 @@ static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk) return nsec + arch_gettimeoffset(); } +static RAW_NOTIFIER_HEAD(pvclock_gtod_chain); + +static void update_pvclock_gtod(struct timekeeper *tk) +{ + raw_notifier_call_chain(&pvclock_gtod_chain, 0, tk); +} + +/** + * pvclock_gtod_register_notifier - register a pvclock timedata update listener + * + * Must hold write on timekeeper.lock + */ +int pvclock_gtod_register_notifier(struct notifier_block *nb) +{ + struct timekeeper *tk = &timekeeper; + unsigned long flags; + int ret; + + write_seqlock_irqsave(&tk->lock, flags); + ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb); + /* update timekeeping data */ + update_pvclock_gtod(tk); + write_sequnlock_irqrestore(&tk->lock, flags); + + return ret; +} +EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier); + +/** + * pvclock_gtod_unregister_notifier - unregister a pvclock + * timedata update listener + * + * Must hold write on timekeeper.lock + */ +int pvclock_gtod_unregister_notifier(struct notifier_block *nb) +{ + struct timekeeper *tk = &timekeeper; + unsigned long flags; + int ret; + + write_seqlock_irqsave(&tk->lock, flags); + ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb); + write_sequnlock_irqrestore(&tk->lock, flags); + + return ret; +} +EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier); + /* must hold write on timekeeper.lock */ static void timekeeping_update(struct timekeeper *tk, bool clearntp) { @@ -188,6 +237,7 @@ static void timekeeping_update(struct timekeeper *tk, bool clearntp) ntp_clear(); } update_vsyscall(tk); + update_pvclock_gtod(tk); } /** |