From 4c3711d7fb4763c63b2654f2d07cbe21ca5aadd4 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 31 Aug 2017 17:12:48 +0200 Subject: timekeeping: Provide NMI safe access to clock realtime The configurable printk timestamping wants access to clock realtime. Right now there is no ktime_get_real_fast_ns() accessor because reading the monotonic base and the realtime offset cannot be done atomically. Contrary to boot time this offset can change during runtime and cause half updated readouts. struct tk_read_base was fully packed when the fast timekeeper access was implemented. commit ceea5e3771ed ("time: Fix clock->read(clock) race around clocksource changes") removed the 'read' function pointer from the structure, but of course left the comment stale. So now the structure can fit a new 64bit member w/o violating the cache line constraints. Add real_base to tk_read_base and update it in the fast timekeeper update sequence. Implement an accessor which follows the same scheme as the accessor to clock monotonic, but uses the new real_base to access clock real time. The runtime overhead for updating real_base is minimal as it just adds two cache hot values and stores them into an already dirtied cache line along with the other fast timekeeper updates. Signed-off-by: Thomas Gleixner Cc: Prarit Bhargava Cc: John Stultz Cc: Peter Zijlstra Link: https://lkml.kernel.org/r/1505757060-2004-3-git-send-email-prarit@redhat.com --- include/linux/timekeeping.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/timekeeping.h') diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index ddc229ff6d1e..eb98cbdbb323 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -239,6 +239,7 @@ static inline u64 ktime_get_raw_ns(void) extern u64 ktime_get_mono_fast_ns(void); extern u64 ktime_get_raw_fast_ns(void); extern u64 ktime_get_boot_fast_ns(void); +extern u64 ktime_get_real_fast_ns(void); /* * Timespec interfaces utilizing the ktime based ones -- cgit From 6546911ed369af8d747215ff8b6144618e91c6ab Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 19 Oct 2017 13:14:49 +0200 Subject: time: Move old timekeeping interfaces to timekeeping32.h The interfaces based on 'struct timespec' and 'unsigned long' seconds are no longer recommended for new code, and we are trying to migrate to ktime_t based interfaces and other y2038-safe variants. This moves all the legacy interfaces from linux/timekeeping.h into a new timekeeping32.h to better document this. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Miroslav Lichvar Cc: Richard Cochran Cc: Prarit Bhargava Cc: Stephen Boyd Signed-off-by: Arnd Bergmann Signed-off-by: John Stultz --- include/linux/timekeeping.h | 137 +------------------------------------------- 1 file changed, 2 insertions(+), 135 deletions(-) (limited to 'include/linux/timekeeping.h') diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index ddc229ff6d1e..405beea4e71b 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -15,27 +15,16 @@ extern void xtime_update(unsigned long ticks); /* * Get and set timeofday */ -extern void do_gettimeofday(struct timeval *tv); extern int do_settimeofday64(const struct timespec64 *ts); extern int do_sys_settimeofday64(const struct timespec64 *tv, const struct timezone *tz); /* * Kernel time accessors */ -unsigned long get_seconds(void); struct timespec64 current_kernel_time64(void); -/* does not take xtime_lock */ -struct timespec __current_kernel_time(void); - -static inline struct timespec current_kernel_time(void) -{ - struct timespec64 now = current_kernel_time64(); - - return timespec64_to_timespec(now); -} /* - * timespec based interfaces + * timespec64 based interfaces */ struct timespec64 get_monotonic_coarse64(void); extern void getrawmonotonic64(struct timespec64 *ts); @@ -47,116 +36,6 @@ extern int __getnstimeofday64(struct timespec64 *tv); extern void getnstimeofday64(struct timespec64 *tv); extern void getboottime64(struct timespec64 *ts); -#if BITS_PER_LONG == 64 -/** - * Deprecated. Use do_settimeofday64(). - */ -static inline int do_settimeofday(const struct timespec *ts) -{ - return do_settimeofday64(ts); -} - -static inline int __getnstimeofday(struct timespec *ts) -{ - return __getnstimeofday64(ts); -} - -static inline void getnstimeofday(struct timespec *ts) -{ - getnstimeofday64(ts); -} - -static inline void ktime_get_ts(struct timespec *ts) -{ - ktime_get_ts64(ts); -} - -static inline void ktime_get_real_ts(struct timespec *ts) -{ - getnstimeofday64(ts); -} - -static inline void getrawmonotonic(struct timespec *ts) -{ - getrawmonotonic64(ts); -} - -static inline struct timespec get_monotonic_coarse(void) -{ - return get_monotonic_coarse64(); -} - -static inline void getboottime(struct timespec *ts) -{ - return getboottime64(ts); -} -#else -/** - * Deprecated. Use do_settimeofday64(). - */ -static inline int do_settimeofday(const struct timespec *ts) -{ - struct timespec64 ts64; - - ts64 = timespec_to_timespec64(*ts); - return do_settimeofday64(&ts64); -} - -static inline int __getnstimeofday(struct timespec *ts) -{ - struct timespec64 ts64; - int ret = __getnstimeofday64(&ts64); - - *ts = timespec64_to_timespec(ts64); - return ret; -} - -static inline void getnstimeofday(struct timespec *ts) -{ - struct timespec64 ts64; - - getnstimeofday64(&ts64); - *ts = timespec64_to_timespec(ts64); -} - -static inline void ktime_get_ts(struct timespec *ts) -{ - struct timespec64 ts64; - - ktime_get_ts64(&ts64); - *ts = timespec64_to_timespec(ts64); -} - -static inline void ktime_get_real_ts(struct timespec *ts) -{ - struct timespec64 ts64; - - getnstimeofday64(&ts64); - *ts = timespec64_to_timespec(ts64); -} - -static inline void getrawmonotonic(struct timespec *ts) -{ - struct timespec64 ts64; - - getrawmonotonic64(&ts64); - *ts = timespec64_to_timespec(ts64); -} - -static inline struct timespec get_monotonic_coarse(void) -{ - return timespec64_to_timespec(get_monotonic_coarse64()); -} - -static inline void getboottime(struct timespec *ts) -{ - struct timespec64 ts64; - - getboottime64(&ts64); - *ts = timespec64_to_timespec(ts64); -} -#endif - #define ktime_get_real_ts64(ts) getnstimeofday64(ts) /* @@ -241,23 +120,13 @@ extern u64 ktime_get_raw_fast_ns(void); extern u64 ktime_get_boot_fast_ns(void); /* - * Timespec interfaces utilizing the ktime based ones + * timespec64 interfaces utilizing the ktime based ones */ -static inline void get_monotonic_boottime(struct timespec *ts) -{ - *ts = ktime_to_timespec(ktime_get_boottime()); -} - static inline void get_monotonic_boottime64(struct timespec64 *ts) { *ts = ktime_to_timespec64(ktime_get_boottime()); } -static inline void timekeeping_clocktai(struct timespec *ts) -{ - *ts = ktime_to_timespec(ktime_get_clocktai()); -} - static inline void timekeeping_clocktai64(struct timespec64 *ts) { *ts = ktime_to_timespec64(ktime_get_clocktai()); @@ -340,10 +209,8 @@ extern void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot); */ extern int persistent_clock_is_local; -extern void read_persistent_clock(struct timespec *ts); extern void read_persistent_clock64(struct timespec64 *ts); extern void read_boot_clock64(struct timespec64 *ts); -extern int update_persistent_clock(struct timespec now); extern int update_persistent_clock64(struct timespec64 now); -- cgit