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Commit d8201269 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'timers-2038-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull more 2038 timer work from Thomas Gleixner:
 "Two more patches for the ongoing 2038 work:

   - New accessors to clock MONOTONIC and REALTIME seconds

  This is a seperate branch as Arnd has follow up work depending on
  this"

* 'timers-2038-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Provide y2038 safe accessor to the seconds portion of CLOCK_REALTIME
  timekeeping: Provide fast accessor to the seconds part of CLOCK_MONOTONIC
parents 3eb5b893 dbe7aa62

include/linux/timekeeper_internal.h

+2 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ struct tk_read_base { 
 * struct timekeeper - Structure holding internal timekeeping values.

 * @tkr:		The readout base structure

 * @xtime_sec:		Current CLOCK_REALTIME time in seconds

 * @ktime_sec:		Current CLOCK_MONOTONIC time in seconds

 * @wall_to_monotonic:	CLOCK_REALTIME to CLOCK_MONOTONIC offset

 * @offs_real:		Offset clock monotonic -> clock realtime

 * @offs_boot:		Offset clock monotonic -> clock boottime
@@ -77,6 +78,7 @@ struct tk_read_base { 
struct timekeeper {

	struct tk_read_base	tkr;

	u64			xtime_sec;

	unsigned long		ktime_sec;

	struct timespec64	wall_to_monotonic;

	ktime_t			offs_real;

	ktime_t			offs_boot;

include/linux/timekeeping.h

+2 −0
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ struct timespec __current_kernel_time(void); 
struct timespec64 get_monotonic_coarse64(void);

extern void getrawmonotonic64(struct timespec64 *ts);

extern void ktime_get_ts64(struct timespec64 *ts);

extern time64_t ktime_get_seconds(void);

extern time64_t ktime_get_real_seconds(void);



extern int __getnstimeofday64(struct timespec64 *tv);

extern void getnstimeofday64(struct timespec64 *tv);

kernel/time/timekeeping.c

+63 −5
Original line number Diff line number Diff line
@@ -417,7 +417,8 @@ EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier); 
 */

static inline void tk_update_ktime_data(struct timekeeper *tk)

{

	s64 nsec;

	u64 seconds;

	u32 nsec;



	/*

	 * The xtime based monotonic readout is:
@@ -426,13 +427,22 @@ static inline void tk_update_ktime_data(struct timekeeper *tk) 
	 *	nsec = base_mono + now();

	 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec

	 */

	nsec = (s64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);

	nsec *= NSEC_PER_SEC;

	nsec += tk->wall_to_monotonic.tv_nsec;

	tk->tkr.base_mono = ns_to_ktime(nsec);

	seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);

	nsec = (u32) tk->wall_to_monotonic.tv_nsec;

	tk->tkr.base_mono = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);



	/* Update the monotonic raw base */

	tk->base_raw = timespec64_to_ktime(tk->raw_time);



	/*

	 * The sum of the nanoseconds portions of xtime and

	 * wall_to_monotonic can be greater/equal one second. Take

	 * this into account before updating tk->ktime_sec.

	 */

	nsec += (u32)(tk->tkr.xtime_nsec >> tk->tkr.shift);

	if (nsec >= NSEC_PER_SEC)

		seconds++;

	tk->ktime_sec = seconds;

}



/* must hold timekeeper_lock */
@@ -648,6 +658,54 @@ void ktime_get_ts64(struct timespec64 *ts) 
}

EXPORT_SYMBOL_GPL(ktime_get_ts64);



/**

 * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC

 *

 * Returns the seconds portion of CLOCK_MONOTONIC with a single non

 * serialized read. tk->ktime_sec is of type 'unsigned long' so this

 * works on both 32 and 64 bit systems. On 32 bit systems the readout

 * covers ~136 years of uptime which should be enough to prevent

 * premature wrap arounds.

 */

time64_t ktime_get_seconds(void)

{

	struct timekeeper *tk = &tk_core.timekeeper;



	WARN_ON(timekeeping_suspended);

	return tk->ktime_sec;

}

EXPORT_SYMBOL_GPL(ktime_get_seconds);



/**

 * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME

 *

 * Returns the wall clock seconds since 1970. This replaces the

 * get_seconds() interface which is not y2038 safe on 32bit systems.

 *

 * For 64bit systems the fast access to tk->xtime_sec is preserved. On

 * 32bit systems the access must be protected with the sequence

 * counter to provide "atomic" access to the 64bit tk->xtime_sec

 * value.

 */

time64_t ktime_get_real_seconds(void)

{

	struct timekeeper *tk = &tk_core.timekeeper;

	time64_t seconds;

	unsigned int seq;



	if (IS_ENABLED(CONFIG_64BIT))

		return tk->xtime_sec;



	do {

		seq = read_seqcount_begin(&tk_core.seq);

		seconds = tk->xtime_sec;



	} while (read_seqcount_retry(&tk_core.seq, seq));



	return seconds;

}

EXPORT_SYMBOL_GPL(ktime_get_real_seconds);



#ifdef CONFIG_NTP_PPS



/**