Release 4.15 kernel/time/timekeeping.c

Directory: kernel/time
/*
 *  linux/kernel/time/timekeeping.c
 *
 *  Kernel timekeeping code and accessor functions
 *
 *  This code was moved from linux/kernel/timer.c.
 *  Please see that file for copyright and history logs.
 *
 */

#include <linux/timekeeper_internal.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/nmi.h>
#include <linux/sched.h>
#include <linux/sched/loadavg.h>
#include <linux/syscore_ops.h>
#include <linux/clocksource.h>
#include <linux/jiffies.h>
#include <linux/time.h>
#include <linux/tick.h>
#include <linux/stop_machine.h>
#include <linux/pvclock_gtod.h>
#include <linux/compiler.h>

#include "tick-internal.h"
#include "ntp_internal.h"
#include "timekeeping_internal.h"


#define TK_CLEAR_NTP		(1 << 0)

#define TK_MIRROR		(1 << 1)

#define TK_CLOCK_WAS_SET	(1 << 2)

/*
 * The most important data for readout fits into a single 64 byte
 * cache line.
 */
static struct {
	
seqcount_t		seq;
	
struct timekeeper	timekeeper;

} tk_core ____cacheline_aligned;

static DEFINE_RAW_SPINLOCK(timekeeper_lock);

static struct timekeeper shadow_timekeeper;

/**
 * struct tk_fast - NMI safe timekeeper
 * @seq:        Sequence counter for protecting updates. The lowest bit
 *              is the index for the tk_read_base array
 * @base:       tk_read_base array. Access is indexed by the lowest bit of
 *              @seq.
 *
 * See @update_fast_timekeeper() below.
 */

struct tk_fast {
	
seqcount_t		seq;
	
struct tk_read_base	base[2];
};

/* Suspend-time cycles value for halted fast timekeeper. */

static u64 cycles_at_suspend;



static u64 dummy_clock_read(struct clocksource *cs)
{
	return cycles_at_suspend;
}

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static struct clocksource dummy_clock = {
	.read = dummy_clock_read,
};


static struct tk_fast tk_fast_mono ____cacheline_aligned = {
	.base[0] = { .clock = &dummy_clock, },
	.base[1] = { .clock = &dummy_clock, },
};


static struct tk_fast tk_fast_raw  ____cacheline_aligned = {
	.base[0] = { .clock = &dummy_clock, },
	.base[1] = { .clock = &dummy_clock, },
};

/* flag for if timekeeping is suspended */

int __read_mostly timekeeping_suspended;



static inline void tk_normalize_xtime(struct timekeeper *tk)
{
	while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
		tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
		tk->xtime_sec++;
	}
	while (tk->tkr_raw.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_raw.shift)) {
		tk->tkr_raw.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
		tk->raw_sec++;
	}
}

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static inline struct timespec64 tk_xtime(struct timekeeper *tk)
{
	struct timespec64 ts;

	ts.tv_sec = tk->xtime_sec;
	ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
	return ts;
}

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static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
{
	tk->xtime_sec = ts->tv_sec;
	tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
}

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static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
{
	tk->xtime_sec += ts->tv_sec;
	tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
	tk_normalize_xtime(tk);
}

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static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
{
	struct timespec64 tmp;

	/*
         * Verify consistency of: offset_real = -wall_to_monotonic
         * before modifying anything
         */
	set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
					-tk->wall_to_monotonic.tv_nsec);
	WARN_ON_ONCE(tk->offs_real != timespec64_to_ktime(tmp));
	tk->wall_to_monotonic = wtm;
	set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
	tk->offs_real = timespec64_to_ktime(tmp);
	tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
}

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static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
{
	tk->offs_boot = ktime_add(tk->offs_boot, delta);
}

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/*
 * tk_clock_read - atomic clocksource read() helper
 *
 * This helper is necessary to use in the read paths because, while the
 * seqlock ensures we don't return a bad value while structures are updated,
 * it doesn't protect from potential crashes. There is the possibility that
 * the tkr's clocksource may change between the read reference, and the
 * clock reference passed to the read function.  This can cause crashes if
 * the wrong clocksource is passed to the wrong read function.
 * This isn't necessary to use when holding the timekeeper_lock or doing
 * a read of the fast-timekeeper tkrs (which is protected by its own locking
 * and update logic).
 */


static inline u64 tk_clock_read(struct tk_read_base *tkr)
{
	struct clocksource *clock = READ_ONCE(tkr->clock);

	return clock->read(clock);
}

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#ifdef CONFIG_DEBUG_TIMEKEEPING

#define WARNING_FREQ (HZ*300) 
/* 5 minute rate-limiting */



static void timekeeping_check_update(struct timekeeper *tk, u64 offset)
{

	u64 max_cycles = tk->tkr_mono.clock->max_cycles;
	const char *name = tk->tkr_mono.clock->name;

	if (offset > max_cycles) {
		printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
				offset, name, max_cycles);
		printk_deferred("         timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
	} else {
		if (offset > (max_cycles >> 1)) {
			printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
					offset, name, max_cycles >> 1);
			printk_deferred("      timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
		}
	}

	if (tk->underflow_seen) {
		if (jiffies - tk->last_warning > WARNING_FREQ) {
			printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
			printk_deferred("         Please report this, consider using a different clocksource, if possible.\n");
			printk_deferred("         Your kernel is probably still fine.\n");
			tk->last_warning = jiffies;
		}
		tk->underflow_seen = 0;
	}

	if (tk->overflow_seen) {
		if (jiffies - tk->last_warning > WARNING_FREQ) {
			printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
			printk_deferred("         Please report this, consider using a different clocksource, if possible.\n");
			printk_deferred("         Your kernel is probably still fine.\n");
			tk->last_warning = jiffies;
		}
		tk->overflow_seen = 0;
	}
}

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Total 193 100.00% 7 100.00%



static inline u64 timekeeping_get_delta(struct tk_read_base *tkr)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	u64 now, last, mask, max, delta;
	unsigned int seq;

	/*
         * Since we're called holding a seqlock, the data may shift
         * under us while we're doing the calculation. This can cause
         * false positives, since we'd note a problem but throw the
         * results away. So nest another seqlock here to atomically
         * grab the points we are checking with.
         */
	do {
		seq = read_seqcount_begin(&tk_core.seq);
		now = tk_clock_read(tkr);
		last = tkr->cycle_last;
		mask = tkr->mask;
		max = tkr->clock->max_cycles;
	} while (read_seqcount_retry(&tk_core.seq, seq));

	delta = clocksource_delta(now, last, mask);

	/*
         * Try to catch underflows by checking if we are seeing small
         * mask-relative negative values.
         */
	if (unlikely((~delta & mask) < (mask >> 3))) {
		tk->underflow_seen = 1;
		delta = 0;
	}

	/* Cap delta value to the max_cycles values to avoid mult overflows */
	if (unlikely(delta > max)) {
		tk->overflow_seen = 1;
		delta = tkr->clock->max_cycles;
	}

	return delta;
}
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#else


static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset)
{
}
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static inline u64 timekeeping_get_delta(struct tk_read_base *tkr)
{
	u64 cycle_now, delta;

	/* read clocksource */
	cycle_now = tk_clock_read(tkr);

	/* calculate the delta since the last update_wall_time */
	delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);

	return delta;
}
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#endif

/**
 * tk_setup_internals - Set up internals to use clocksource clock.
 *
 * @tk:         The target timekeeper to setup.
 * @clock:              Pointer to clocksource.
 *
 * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
 * pair and interval request.
 *
 * Unless you're the timekeeping code, you should not be using this!
 */


static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
{
	u64 interval;
	u64 tmp, ntpinterval;
	struct clocksource *old_clock;

	++tk->cs_was_changed_seq;
	old_clock = tk->tkr_mono.clock;
	tk->tkr_mono.clock = clock;
	tk->tkr_mono.mask = clock->mask;
	tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);

	tk->tkr_raw.clock = clock;
	tk->tkr_raw.mask = clock->mask;
	tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;

	/* Do the ns -> cycle conversion first, using original mult */
	tmp = NTP_INTERVAL_LENGTH;
	tmp <<= clock->shift;
	ntpinterval = tmp;
	tmp += clock->mult/2;
	do_div(tmp, clock->mult);
	if (tmp == 0)
		tmp = 1;

	interval = (u64) tmp;
	tk->cycle_interval = interval;

	/* Go back from cycles -> shifted ns */
	tk->xtime_interval = interval * clock->mult;
	tk->xtime_remainder = ntpinterval - tk->xtime_interval;
	tk->raw_interval = interval * clock->mult;

	 /* if changing clocks, convert xtime_nsec shift units */
	if (old_clock) {
		int shift_change = clock->shift - old_clock->shift;
		if (shift_change < 0) {
			tk->tkr_mono.xtime_nsec >>= -shift_change;
			tk->tkr_raw.xtime_nsec >>= -shift_change;
		} else {
			tk->tkr_mono.xtime_nsec <<= shift_change;
			tk->tkr_raw.xtime_nsec <<= shift_change;
		}
	}

	tk->tkr_mono.shift = clock->shift;
	tk->tkr_raw.shift = clock->shift;

	tk->ntp_error = 0;
	tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
	tk->ntp_tick = ntpinterval << tk->ntp_error_shift;

	/*
         * The timekeeper keeps its own mult values for the currently
         * active clocksource. These value will be adjusted via NTP
         * to counteract clock drifting.
         */
	tk->tkr_mono.mult = clock->mult;
	tk->tkr_raw.mult = clock->mult;
	tk->ntp_err_mult = 0;
}

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Total 326 100.00% 17 100.00%

/* Timekeeper helper functions. */

#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET


static u32 default_arch_gettimeoffset(void) { return 0; }
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u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
#else


static inline u32 arch_gettimeoffset(void) { return 0; }
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#endif



static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr, u64 delta)
{
	u64 nsec;

	nsec = delta * tkr->mult + tkr->xtime_nsec;
	nsec >>= tkr->shift;

	/* If arch requires, add in get_arch_timeoffset() */
	return nsec + arch_gettimeoffset();
}

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Stephen Warren 1 2.33% 1 8.33%
Total 43 100.00% 12 100.00%



static inline u64 timekeeping_get_ns(struct tk_read_base *tkr)
{
	u64 delta;

	delta = timekeeping_get_delta(tkr);
	return timekeeping_delta_to_ns(tkr, delta);
}

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static inline u64 timekeeping_cycles_to_ns(struct tk_read_base *tkr, u64 cycles)
{
	u64 delta;

	/* calculate the delta since the last update_wall_time */
	delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
	return timekeeping_delta_to_ns(tkr, delta);
}

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/**
 * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
 * @tkr: Timekeeping readout base from which we take the update
 *
 * We want to use this from any context including NMI and tracing /
 * instrumenting the timekeeping code itself.
 *
 * Employ the latch technique; see @raw_write_seqcount_latch.
 *
 * So if a NMI hits the update of base[0] then it will use base[1]
 * which is still consistent. In the worst case this can result is a
 * slightly wrong timestamp (a few nanoseconds). See
 * @ktime_get_mono_fast_ns.
 */


static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf)
{
	struct tk_read_base *base = tkf->base;

	/* Force readers off to base[1] */
	raw_write_seqcount_latch(&tkf->seq);

	/* Update base[0] */
	memcpy(base, tkr, sizeof(*base));

	/* Force readers back to base[0] */
	raw_write_seqcount_latch(&tkf->seq);

	/* Update base[1] */
	memcpy(base + 1, base, sizeof(*base));
}

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/**
 * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
 *
 * This timestamp is not guaranteed to be monotonic across an update.
 * The timestamp is calculated by:
 *
 *      now = base_mono + clock_delta * slope
 *
 * So if the update lowers the slope, readers who are forced to the
 * not yet updated second array are still using the old steeper slope.
 *
 * tmono
 * ^
 * |    o  n
 * |   o n
 * |  u
 * | o
 * |o
 * |12345678---> reader order
 *
 * o = old slope
 * u = update
 * n = new slope
 *
 * So reader 6 will observe time going backwards versus reader 5.
 *
 * While other CPUs are likely to be able observe that, the only way
 * for a CPU local observation is when an NMI hits in the middle of
 * the update. Timestamps taken from that NMI context might be ahead
 * of the following timestamps. Callers need to be aware of that and
 * deal with it.
 */


static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
{
	struct tk_read_base *tkr;
	unsigned int seq;
	u64 now;

	do {
		seq = raw_read_seqcount_latch(&tkf->seq);
		tkr = tkf->base + (seq & 0x01);
		now = ktime_to_ns(tkr->base);

		now += timekeeping_delta_to_ns(tkr,
				clocksource_delta(
					tk_clock_read(tkr),
					tkr->cycle_last,
					tkr->mask));
	} while (read_seqcount_retry(&tkf->seq, seq));

	return now;
}

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u64 ktime_get_mono_fast_ns(void)
{
	return __ktime_get_fast_ns(&tk_fast_mono);
}
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EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);



u64 ktime_get_raw_fast_ns(void)
{
	return __ktime_get_fast_ns(&tk_fast_raw);
}
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EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);

/**
 * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.
 *
 * To keep it NMI safe since we're accessing from tracing, we're not using a
 * separate timekeeper with updates to monotonic clock and boot offset
 * protected with seqlocks. This has the following minor side effects:
 *
 * (1) Its possible that a timestamp be taken after the boot offset is updated
 * but before the timekeeper is updated. If this happens, the new boot offset
 * is added to the old timekeeping making the clock appear to update slightly
 * earlier:
 *    CPU 0                                        CPU 1
 *    timekeeping_inject_sleeptime64()
 *    __timekeeping_inject_sleeptime(tk, delta);
 *                                                 timestamp();
 *    timekeeping_update(tk, TK_CLEAR_NTP...);
 *
 * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be
 * partially updated.  Since the tk->offs_boot update is a rare event, this
 * should be a rare occurrence which postprocessing should be able to handle.
 */


u64 notrace ktime_get_boot_fast_ns(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;

	return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot));
}
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EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);


/*
 * See comment for __ktime_get_fast_ns() vs. timestamp ordering
 */


static __always_inline u64 __ktime_get_real_fast_ns(struct tk_fast *tkf)
{
	struct tk_read_base *tkr;
	unsigned int seq;
	u64 now;

	do {
		seq = raw_read_seqcount_latch(&tkf->seq);
		tkr = tkf->base + (seq & 0x01);
		now = ktime_to_ns(tkr->base_real);

		now += timekeeping_delta_to_ns(tkr,
				clocksource_delta(
					tk_clock_read(tkr),
					tkr->cycle_last,
					tkr->mask));
	} while (read_seqcount_retry(&tkf->seq, seq));

	return now;
}

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/**
 * ktime_get_real_fast_ns: - NMI safe and fast access to clock realtime.
 */


u64 ktime_get_real_fast_ns(void)
{
	return __ktime_get_real_fast_ns(&tk_fast_mono);
}
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EXPORT_SYMBOL_GPL(ktime_get_real_fast_ns);

/**
 * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
 * @tk: Timekeeper to snapshot.
 *
 * It generally is unsafe to access the clocksource after timekeeping has been
 * suspended, so take a snapshot of the readout base of @tk and use it as the
 * fast timekeeper's readout base while suspended.  It will return the same
 * number of cycles every time until timekeeping is resumed at which time the
 * proper readout base for the fast timekeeper will be restored automatically.
 */


static void halt_fast_timekeeper(struct timekeeper *tk)
{
	static struct tk_read_base tkr_dummy;
	struct tk_read_base *tkr = &tk->tkr_mono;

	memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
	cycles_at_suspend = tk_clock_read(tkr);
	tkr_dummy.clock = &dummy_clock;
	tkr_dummy.base_real = tkr->base + tk->offs_real;
	update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);

	tkr = &tk->tkr_raw;
	memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
	tkr_dummy.clock = &dummy_clock;
	update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
}

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Total 110 100.00% 6 100.00%

static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);



static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
{
	raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
}

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/**
 * pvclock_gtod_register_notifier - register a pvclock timedata update listener
 */


int pvclock_gtod_register_notifier(struct notifier_block *nb)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned long flags;
	int ret;

	raw_spin_lock_irqsave(&timekeeper_lock, flags);
	ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
	update_pvclock_gtod(tk, true);
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);

	return ret;
}
Contributors
Person Tokens Prop Commits CommitProp
Marcelo Tosatti 55 87.30% 1 20.00%
Thomas Gleixner 6 9.52% 3 60.00%
David Vrabel 2 3.17% 1 20.00%
Total 63 100.00% 5 100.00%


EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);

/**
 * pvclock_gtod_unregister_notifier - unregister a pvclock
 * timedata update listener
 */


int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
{
	unsigned long flags;
	int ret;

	raw_spin_lock_irqsave(&timekeeper_lock, flags);
	ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);

	return ret;
}
Contributors
Person Tokens Prop Commits CommitProp
Marcelo Tosatti 42 91.30% 1 33.33%
Thomas Gleixner 4 8.70% 2 66.67%
Total 46 100.00% 3 100.00%


EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);

/*
 * tk_update_leap_state - helper to update the next_leap_ktime
 */


static inline void tk_update_leap_state(struct timekeeper *tk)
{
	tk->next_leap_ktime = ntp_get_next_leap();
	if (tk->next_leap_ktime != KTIME_MAX)
		/* Convert to monotonic time */
		tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 43 100.00% 1 100.00%
Total 43 100.00% 1 100.00%

/*
 * Update the ktime_t based scalar nsec members of the timekeeper
 */


static inline void tk_update_ktime_data(struct timekeeper *tk)
{
	u64 seconds;
	u32 nsec;

	/*
         * The xtime based monotonic readout is:
         *      nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
         * The ktime based monotonic readout is:
         *      nsec = base_mono + now();
         * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
         */
	seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
	nsec = (u32) tk->wall_to_monotonic.tv_nsec;
	tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);

	/*
         * 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_mono.xtime_nsec >> tk->tkr_mono.shift);
	if (nsec >= NSEC_PER_SEC)
		seconds++;
	tk->ktime_sec = seconds;

	/* Update the monotonic raw base */
	tk->tkr_raw.base = ns_to_ktime(tk->raw_sec * NSEC_PER_SEC);
}

Contributors
Person Tokens Prop Commits CommitProp
Heena Sirwani 47 41.59% 1 16.67%
Thomas Gleixner 46 40.71% 2 33.33%
John Stultz 16 14.16% 2 33.33%
Peter Zijlstra 4 3.54% 1 16.67%
Total 113 100.00% 6 100.00%

/* must hold timekeeper_lock */


static void timekeeping_update(struct timekeeper *tk, unsigned int action)
{
	if (action & TK_CLEAR_NTP) {
		tk->ntp_error = 0;
		ntp_clear();
	}

	tk_update_leap_state(tk);
	tk_update_ktime_data(tk);

	update_vsyscall(tk);
	update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);

	tk->tkr_mono.base_real = tk->tkr_mono.base + tk->offs_real;
	update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
	update_fast_timekeeper(&tk->tkr_raw,  &tk_fast_raw);

	if (action & TK_CLOCK_WAS_SET)
		tk->clock_was_set_seq++;
	/*
         * The mirroring of the data to the shadow-timekeeper needs
         * to happen last here to ensure we don't over-write the
         * timekeeper structure on the next update with stale data
         */
	if (action & TK_MIRROR)
		memcpy(&shadow_timekeeper, &tk_core.timekeeper,
		       sizeof(tk_core.timekeeper));
}

Contributors
Person Tokens Prop Commits CommitProp
Thomas Gleixner 58 44.62% 5 31.25%
John Stultz 40 30.77% 4 25.00%
Peter Zijlstra 15 11.54% 3 18.75%
David Vrabel 10 7.69% 2 12.50%
Marcelo Tosatti 5 3.85% 1 6.25%
Rafael J. Wysocki 2 1.54% 1 6.25%
Total 130 100.00% 16 100.00%

/**
 * timekeeping_forward_now - update clock to the current time
 *
 * Forward the current clock to update its state since the last call to
 * update_wall_time(). This is useful before significant clock changes,
 * as it avoids having to deal with this time offset explicitly.
 */


static void timekeeping_forward_now(struct timekeeper *tk)
{
	u64 cycle_now, delta;

	cycle_now = tk_clock_read(&tk->tkr_mono);
	delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
	tk->tkr_mono.cycle_last = cycle_now;
	tk->tkr_raw.cycle_last  = cycle_now;

	tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;

	/* If arch requires, add in get_arch_timeoffset() */
	tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;


	tk->tkr_raw.xtime_nsec += delta * tk->tkr_raw.mult;

	/* If arch requires, add in get_arch_timeoffset() */
	tk->tkr_raw.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_raw.shift;

	tk_normalize_xtime(tk);
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 70 53.03% 7 31.82%
Thomas Gleixner 27 20.45% 7 31.82%
Peter Zijlstra 22 16.67% 2 9.09%
Martin Schwidefsky 6 4.55% 3 13.64%
Andreas Schwab 3 2.27% 1 4.55%
Roman Zippel 3 2.27% 1 4.55%
Stephen Warren 1 0.76% 1 4.55%
Total 132 100.00% 22 100.00%

/**
 * __getnstimeofday64 - Returns the time of day in a timespec64.
 * @ts:         pointer to the timespec to be set
 *
 * Updates the time of day in the timespec.
 * Returns 0 on success, or -ve when suspended (timespec will be undefined).
 */


int __getnstimeofday64(struct timespec64 *ts)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned long seq;
	u64 nsecs;

	do {
		seq = read_seqcount_begin(&tk_core.seq);

		ts->tv_sec = tk->xtime_sec;
		nsecs = timekeeping_get_ns(&tk->tkr_mono);

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

	ts->tv_nsec = 0;
	timespec64_add_ns(ts, nsecs);

	/*
         * Do not bail out early, in case there were callers still using
         * the value, even in the face of the WARN_ON.
         */
	if (unlikely(timekeeping_suspended))
		return -EAGAIN;
	return 0;
}
Contributors
Person Tokens Prop Commits CommitProp
John Stultz 64 64.65% 5 38.46%
Kees Cook 17 17.17% 1 7.69%
Thomas Gleixner 16 16.16% 5 38.46%
Martin Schwidefsky 1 1.01% 1 7.69%
Peter Zijlstra 1 1.01% 1 7.69%
Total 99 100.00% 13 100.00%


EXPORT_SYMBOL(__getnstimeofday64);

/**
 * getnstimeofday64 - Returns the time of day in a timespec64.
 * @ts:         pointer to the timespec64 to be set
 *
 * Returns the time of day in a timespec64 (WARN if suspended).
 */


void getnstimeofday64(struct timespec64 *ts)
{
	WARN_ON(__getnstimeofday64(ts));
}
Contributors
Person Tokens Prop Commits CommitProp
Kees Cook 14 77.78% 1 33.33%
Thomas Gleixner 3 16.67% 1 33.33%
John Stultz 1 5.56% 1 33.33%
Total 18 100.00% 3 100.00%


EXPORT_SYMBOL(getnstimeofday64);



ktime_t ktime_get(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned int seq;
	ktime_t base;
	u64 nsecs;

	WARN_ON(timekeeping_suspended);

	do {
		seq = read_seqcount_begin(&tk_core.seq);
		base = tk->tkr_mono.base;
		nsecs = timekeeping_get_ns(&tk->tkr_mono);

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

	return ktime_add_ns(base, nsecs);
}
Contributors
Person Tokens Prop Commits CommitProp
Martin Schwidefsky 47 55.95% 1 9.09%
Thomas Gleixner 20 23.81% 6 54.55%
John Stultz 14 16.67% 3 27.27%
Peter Zijlstra 3 3.57% 1 9.09%
Total 84 100.00% 11 100.00%


EXPORT_SYMBOL_GPL(ktime_get);



u32 ktime_get_resolution_ns(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned int seq;
	u32 nsecs;

	WARN_ON(timekeeping_suspended);

	do {
		seq = read_seqcount_begin(&tk_core.seq);
		nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
	} while (read_seqcount_retry(&tk_core.seq, seq));

	return nsecs;
}
Contributors
Person Tokens Prop Commits CommitProp
Harald Geyer 72 100.00% 1 100.00%
Total 72 100.00% 1 100.00%


EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);


static ktime_t *offsets[TK_OFFS_MAX] = {
	[TK_OFFS_REAL]	= &tk_core.timekeeper.offs_real,
	[TK_OFFS_BOOT]	= &tk_core.timekeeper.offs_boot,
	[TK_OFFS_TAI]	= &tk_core.timekeeper.offs_tai,
};



ktime_t ktime_get_with_offset(enum tk_offsets offs)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned int seq;
	ktime_t base, *offset = offsets[offs];
	u64 nsecs;

	WARN_ON(timekeeping_suspended);

	do {
		seq = read_seqcount_begin(&tk_core.seq);
		base = ktime_add(tk->tkr_mono.base, *offset);
		nsecs = timekeeping_get_ns(&tk->tkr_mono);

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

	return ktime_add_ns(base, nsecs);

}
Contributors
Person Tokens Prop Commits CommitProp
Thomas Gleixner 97 97.00% 4 80.00%
Peter Zijlstra 3 3.00% 1 20.00%
Total 100 100.00% 5 100.00%


EXPORT_SYMBOL_GPL(ktime_get_with_offset);

/**
 * ktime_mono_to_any() - convert mononotic time to any other time
 * @tmono:      time to convert.
 * @offs:       which offset to use
 */


ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
{
	ktime_t *offset = offsets[offs];
	unsigned long seq;
	ktime_t tconv;

	do {
		seq = read_seqcount_begin(&tk_core.seq);
		tconv = ktime_add(tmono, *offset);
	} while (read_seqcount_retry(&tk_core.seq, seq));

	return tconv;
}
Contributors
Person Tokens Prop Commits CommitProp
Thomas Gleixner 67 100.00% 1 100.00%
Total 67 100.00% 1 100.00%


EXPORT_SYMBOL_GPL(ktime_mono_to_any);

/**
 * ktime_get_raw - Returns the raw monotonic time in ktime_t format
 */


ktime_t ktime_get_raw(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned int seq;
	ktime_t base;
	u64 nsecs;

	do {
		seq = read_seqcount_begin(&tk_core.seq);
		base = tk->tkr_raw.base;
		nsecs = timekeeping_get_ns(&tk->tkr_raw);

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

	return ktime_add_ns(base, nsecs);
}
Contributors
Person Tokens Prop Commits CommitProp
Thomas Gleixner 72 91.14% 2 66.67%
Peter Zijlstra 7 8.86% 1 33.33%
Total 79 100.00% 3 100.00%


EXPORT_SYMBOL_GPL(ktime_get_raw);

/**
 * ktime_get_ts64 - get the monotonic clock in timespec64 format
 * @ts:         pointer to timespec variable
 *
 * The function calculates the monotonic clock from the realtime
 * clock and the wall_to_monotonic offset and stores the result
 * in normalized timespec64 format in the variable pointed to by @ts.
 */


void ktime_get_ts64(struct timespec64 *ts)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	struct timespec64 tomono;
	unsigned int seq;
	u64 nsec;

	WARN_ON(timekeeping_suspended);

	do {
		seq = read_seqcount_begin(&tk_core.seq);
		ts->tv_sec = tk->xtime_sec;
		nsec = timekeeping_get_ns(&tk->tkr_mono);
		tomono = tk->wall_to_monotonic;

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

	ts->tv_sec += tomono.tv_sec;
	ts->tv_nsec = 0;
	timespec64_add_ns(ts, nsec + tomono.tv_nsec);
}
Contributors
Person Tokens Prop Commits CommitProp
Martin Schwidefsky 55 49.55% 2 15.38%
John Stultz 31 27.93% 5 38.46%
Thomas Gleixner 24 21.62% 5 38.46%
Peter Zijlstra 1 0.90% 1 7.69%
Total 111 100.00% 13 100.00%


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;
}
Contributors
Person Tokens Prop Commits CommitProp
Heena Sirwani 27 100.00% 1 100.00%
Total 27 100.00% 1 100.00%


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;
}
Contributors
Person Tokens Prop Commits CommitProp
Heena Sirwani 71 100.00% 1 100.00%
Total 71 100.00% 1 100.00%


EXPORT_SYMBOL_GPL(ktime_get_real_seconds);

/**
 * __ktime_get_real_seconds - The same as ktime_get_real_seconds
 * but without the sequence counter protect. This internal function
 * is called just when timekeeping lock is already held.
 */


time64_t __ktime_get_real_seconds(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;

	return tk->xtime_sec;
}

Contributors
Person Tokens Prop Commits CommitProp
DengChao 22 100.00% 1 100.00%
Total 22 100.00% 1 100.00%

/**
 * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
 * @systime_snapshot:   pointer to struct receiving the system time snapshot
 */


void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned long seq;
	ktime_t base_raw;
	ktime_t base_real;
	u64 nsec_raw;
	u64 nsec_real;
	u64 now;

	WARN_ON_ONCE(timekeeping_suspended);

	do {
		seq = read_seqcount_begin(&tk_core.seq);
		now = tk_clock_read(&tk->tkr_mono);
		systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
		systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
		base_real = ktime_add(tk->tkr_mono.base,
				      tk_core.timekeeper.offs_real);
		base_raw = tk->tkr_raw.base;
		nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
		nsec_raw  = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
	} while (read_seqcount_retry(&tk_core.seq, seq));

	systime_snapshot->cycles = now;
	systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
	systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
}
Contributors
Person Tokens Prop Commits CommitProp
Christopher S. Hall 168 97.11% 3 50.00%
Thomas Gleixner 3 1.73% 2 33.33%
John Stultz 2 1.16% 1 16.67%
Total 173 100.00% 6 100.00%


EXPORT_SYMBOL_GPL(ktime_get_snapshot);

/* Scale base by mult/div checking for overflow */


static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
{
	u64 tmp, rem;

	tmp = div64_u64_rem(*base, div, &rem);

	if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
	    ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
		return -EOVERFLOW;
	tmp *= mult;
	rem *= mult;

	do_div(rem, div);
	*base = tmp + rem;
	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Christopher S. Hall 109 100.00% 1 100.00%
Total 109 100.00% 1 100.00%

/**
 * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
 * @history:                    Snapshot representing start of history
 * @partial_history_cycles:     Cycle offset into history (fractional part)
 * @total_history_cycles:       Total history length in cycles
 * @discontinuity:              True indicates clock was set on history period
 * @ts:                         Cross timestamp that should be adjusted using
 *      partial/total ratio
 *
 * Helper function used by get_device_system_crosststamp() to correct the
 * crosstimestamp corresponding to the start of the current interval to the
 * system counter value (timestamp point) provided by the driver. The
 * total_history_* quantities are the total history starting at the provided
 * reference point and ending at the start of the current interval. The cycle
 * count between the driver timestamp point and the start of the current
 * interval is partial_history_cycles.
 */


static int adjust_historical_crosststamp(struct system_time_snapshot *history,
					 u64 partial_history_cycles,
					 u64 total_history_cycles,
					 bool discontinuity,
					 struct system_device_crosststamp *ts)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	u64 corr_raw, corr_real;
	bool interp_forward;
	int ret;

	if (total_history_cycles == 0 || partial_history_cycles == 0)
		return 0;

	/* Interpolate shortest distance from beginning or end of history */
	interp_forward = partial_history_cycles > total_history_cycles / 2;
	partial_history_cycles = interp_forward ?
		total_history_cycles - partial_history_cycles :
		partial_history_cycles;

	/*
         * Scale the monotonic raw time delta by:
         *      partial_history_cycles / total_history_cycles
         */
	corr_raw = (u64)ktime_to_ns(
		ktime_sub(ts->sys_monoraw, history->raw));
	ret = scale64_check_overflow(partial_history_cycles,
				     total_history_cycles, &corr_raw);
	if (ret)
		return ret;

	/*
         * If there is a discontinuity in the history, scale monotonic raw
         *      correction by:
         *      mult(real)/mult(raw) yielding the realtime correction
         * Otherwise, calculate the realtime correction similar to monotonic
         *      raw calculation
         */
	if (discontinuity) {
		corr_real = mul_u64_u32_div
			(corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
	} else {
		corr_real = (u64)ktime_to_ns(
			ktime_sub(ts->sys_realtime, history->real));
		ret = scale64_check_overflow(partial_history_cycles,
					     total_history_cycles, &corr_real);
		if (ret)
			return ret;
	}

	/* Fixup monotonic raw and real time time values */
	if (interp_forward) {
		ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
		ts->sys_realtime = ktime_add_ns(history->real, corr_real);
	} else {
		ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
		ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
	}

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Christopher S. Hall 247 99.20% 1 50.00%
Thomas Gleixner 2 0.80% 1 50.00%
Total 249 100.00% 2 100.00%

/*
 * cycle_between - true if test occurs chronologically between before and after
 */


static bool cycle_between(u64 before, u64 test, u64 after)
{
	if (test > before && test < after)
		return true;
	if (test < before && before > after)
		return true;
	return false;
}

Contributors
Person Tokens Prop Commits CommitProp
Christopher S. Hall 41 93.18% 1 50.00%
Thomas Gleixner 3 6.82% 1 50.00%
Total 44 100.00% 2 100.00%

/**
 * get_device_system_crosststamp - Synchronously capture system/device timestamp
 * @get_time_fn:        Callback to get simultaneous device time and
 *      system counter from the device driver
 * @ctx:                Context passed to get_time_fn()
 * @history_begin:      Historical reference point used to interpolate system
 *      time when counter provided by the driver is before the current interval
 * @xtstamp:            Receives simultaneously captured system and device time
 *
 * Reads a timestamp from a device and correlates it to system time
 */


int get_device_system_crosststamp(int (*get_time_fn)
				  (ktime_t *device_time,
				   struct system_counterval_t *sys_counterval,
				   void *ctx),
				  void *ctx,
				  struct system_time_snapshot *history_begin,
				  struct system_device_crosststamp *xtstamp)
{
	struct system_counterval_t system_counterval;
	struct timekeeper *tk = &tk_core.timekeeper;
	u64 cycles, now, interval_start;
	unsigned int clock_was_set_seq = 0;
	ktime_t base_real, base_raw;
	u64 nsec_real, nsec_raw;
	u8 cs_was_changed_seq;
	unsigned long seq;
	bool do_interp;
	int ret;

	do {
		seq = read_seqcount_begin(&tk_core.seq);
		/*
                 * Try to synchronously capture device time and a system
                 * counter value calling back into the device driver
                 */
		ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
		if (ret)
			return ret;

		/*
                 * Verify that the clocksource associated with the captured
                 * system counter value is the same as the currently installed
                 * timekeeper clocksource
                 */
		if (tk->tkr_mono.clock != system_counterval.cs)
			return -ENODEV;
		cycles = system_counterval.cycles;

		/*
                 * Check whether the system counter value provided by the
                 * device driver is on the current timekeeping interval.
                 */
		now = tk_clock_read(&tk->tkr_mono);
		interval_start = tk->tkr_mono.cycle_last;
		if (!cycle_between(interval_start, cycles, now)) {
			clock_was_set_seq = tk->clock_was_set_seq;
			cs_was_changed_seq = tk->cs_was_changed_seq;
			cycles = interval_start;
			do_interp = true;
		} else {
			do_interp = false;
		}

		base_real = ktime_add(tk->tkr_mono.base,
				      tk_core.timekeeper.offs_real);
		base_raw = tk->tkr_raw.base;

		nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
						     system_counterval.cycles);
		nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
						    system_counterval.cycles);
	} while (read_seqcount_retry(&tk_core.seq, seq));

	xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
	xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);

	/*
         * Interpolate if necessary, adjusting back from the start of the
         * current interval
         */
	if (do_interp) {
		u64 partial_history_cycles, total_history_cycles;
		bool discontinuity;

		/*
                 * Check that the counter value occurs after the provided
                 * history reference and that the history doesn't cross a
                 * clocksource change
                 */
		if (!history_begin ||
		    !cycle_between(history_begin->cycles,
				   system_counterval.cycles, cycles) ||
		    history_begin->cs_was_changed_seq != cs_was_changed_seq)
			return -EINVAL;
		partial_history_cycles = cycles - system_counterval.cycles;
		total_history_cycles = cycles - history_begin->cycles;
		discontinuity =
			history_begin->clock_was_set_seq != clock_was_set_seq;

		ret = adjust_historical_crosststamp(history_begin,
						    partial_history_cycles,
						    total_history_cycles,
						    discontinuity, xtstamp);
		if (ret)
			return ret;
	}

	return 0;
}
Contributors
Person Tokens Prop Commits CommitProp
Christopher S. Hall 383 98.21% 2 33.33%
Thomas Gleixner 3 0.77% 2 33.33%
John Stultz 2 0.51% 1 16.67%
Ingo Molnar 2 0.51% 1 16.67%
Total 390 100.00% 6 100.00%


EXPORT_SYMBOL_GPL(get_device_system_crosststamp);

/**
 * do_gettimeofday - Returns the time of day in a timeval
 * @tv:         pointer to the timeval to be set
 *
 * NOTE: Users should be converted to using getnstimeofday()
 */


void do_gettimeofday(struct timeval *tv)
{
	struct timespec64 now;

	getnstimeofday64(&now);
	tv->tv_sec = now.tv_sec;
	tv->tv_usec = now.tv_nsec/1000;
}
Contributors
Person Tokens Prop Commits CommitProp
John Stultz 36 94.74% 1 50.00%
Thomas Gleixner 2 5.26% 1 50.00%
Total 38 100.00% 2 100.00%


EXPORT_SYMBOL(do_gettimeofday);

/**
 * do_settimeofday64 - Sets the time of day.
 * @ts:     pointer to the timespec64 variable containing the new time
 *
 * Sets the time of day to the new time and update NTP and notify hrtimers
 */


int do_settimeofday64(const struct timespec64 *ts)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	struct timespec64 ts_delta, xt;
	unsigned long flags;
	int ret = 0;

	if (!timespec64_valid_strict(ts))
		return -EINVAL;

	raw_spin_lock_irqsave(&timekeeper_lock, flags);
	write_seqcount_begin(&tk_core.seq);

	timekeeping_forward_now(tk);

	xt = tk_xtime(tk);
	ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
	ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;

	if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
		ret = -EINVAL;
		goto out;
	}

	tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));

	tk_set_xtime(tk, ts);
out:
	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);

	write_seqcount_end(&tk_core.seq);
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);

	/* signal hrtimers about time change */
	clock_was_set();

	return ret;
}
Contributors
Person Tokens Prop Commits CommitProp
John Stultz 96 52.75% 9 45.00%
Wang YanQing 33 18.13% 1 5.00%
Thomas Gleixner 23 12.64% 4 20.00%
Roman Zippel 15 8.24% 1 5.00%
Xunlei Pang 8 4.40% 1 5.00%
David Vrabel 5 2.75% 2 10.00%
Martin Schwidefsky 1 0.55% 1 5.00%
Richard Cochran 1 0.55% 1 5.00%
Total 182 100.00% 20 100.00%


EXPORT_SYMBOL(do_settimeofday64);

/**
 * timekeeping_inject_offset - Adds or subtracts from the current time.
 * @tv:         pointer to the timespec variable containing the offset
 *
 * Adds or subtracts an offset value from the current time.
 */


static int timekeeping_inject_offset(struct timespec64 *ts)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned long flags;
	struct timespec64 tmp;
	int ret = 0;

	if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
		return -EINVAL;

	raw_spin_lock_irqsave(&timekeeper_lock, flags);
	write_seqcount_begin(&tk_core.seq);

	timekeeping_forward_now(tk);

	/* Make sure the proposed value is valid */
	tmp = timespec64_add(tk_xtime(tk), *ts);
	if (timespec64_compare(&tk->wall_to_monotonic, ts) > 0 ||
	    !timespec64_valid_strict(&tmp)) {
		ret = -EINVAL;
		goto error;
	}

	tk_xtime_add(tk, ts);
	tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *ts));

error: /* even if we error out, we forwarded the time, so call update */
	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);

	write_seqcount_end(&tk_core.seq);
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);

	/* signal hrtimers about time change */
	clock_was_set();

	return ret;
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 120 67.80% 9 50.00%
Thomas Gleixner 23 12.99% 4 22.22%
Arnd Bergmann 18 10.17% 2 11.11%
Wang YanQing 11 6.21% 1 5.56%
David Vrabel 5 2.82% 2 11.11%
Total 177 100.00% 18 100.00%

/*
 * Indicates if there is an offset between the system clock and the hardware
 * clock/persistent clock/rtc.
 */

int persistent_clock_is_local;

/*
 * Adjust the time obtained from the CMOS to be UTC time instead of
 * local time.
 *
 * This is ugly, but preferable to the alternatives.  Otherwise we
 * would either need to write a program to do it in /etc/rc (and risk
 * confusion if the program gets run more than once; it would also be
 * hard to make the program warp the clock precisely n hours)  or
 * compile in the timezone information into the kernel.  Bad, bad....
 *
 *                                              - TYT, 1992-01-01
 *
 * The best thing to do is to keep the CMOS clock in universal time (UTC)
 * as real UNIX machines always do it. This avoids all headaches about
 * daylight saving times and warping kernel clocks.
 */


void timekeeping_warp_clock(void)
{
	if (sys_tz.tz_minuteswest != 0) {
		struct timespec64 adjust;

		persistent_clock_is_local = 1;
		adjust.tv_sec = sys_tz.tz_minuteswest * 60;
		adjust.tv_nsec = 0;
		timekeeping_inject_offset(&adjust);
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Arnd Bergmann 44 93.62% 2 66.67%
John Stultz 3 6.38% 1 33.33%
Total 47 100.00% 3 100.00%

/**
 * __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic
 *
 */


static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
{
	tk->tai_offset = tai_offset;
	tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 37 97.37% 3 75.00%
Fengguang Wu 1 2.63% 1 25.00%
Total 38 100.00% 4 100.00%

/**
 * change_clocksource - Swaps clocksources if a new one is available
 *
 * Accumulates current time interval and initializes new clocksource
 */


static int change_clocksource(void *data)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	struct clocksource *new, *old;
	unsigned long flags;

	new = (struct clocksource *) data;

	raw_spin_lock_irqsave(&timekeeper_lock, flags);
	write_seqcount_begin(&tk_core.seq);

	timekeeping_forward_now(tk);
	/*
         * If the cs is in module, get a module reference. Succeeds
         * for built-in code (owner == NULL) as well.
         */
	if (try_module_get(new->owner)) {
		if (!new->enable || new->enable(new) == 0) {
			old = tk->tkr_mono.clock;
			tk_setup_internals(tk, new);
			if (old->disable)
				old->disable(old);
			module_put(old->owner);
		} else {
			module_put(new->owner);
		}
	}
	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);

	write_seqcount_end(&tk_core.seq);
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 54 32.34% 4 23.53%
Thomas Gleixner 53 31.74% 6 35.29%
Martin Schwidefsky 37 22.16% 3 17.65%
Magnus Damm 17 10.18% 1 5.88%
David Vrabel 5 2.99% 2 11.76%
Peter Zijlstra 1 0.60% 1 5.88%
Total 167 100.00% 17 100.00%

/**
 * timekeeping_notify - Install a new clock source
 * @clock:              pointer to the clock source
 *
 * This function is called from clocksource.c after a new, better clock
 * source has been registered. The caller holds the clocksource_mutex.
 */


int timekeeping_notify(struct clocksource *clock)
{
	struct timekeeper *tk = &tk_core.timekeeper;

	if (tk->tkr_mono.clock == clock)
		return 0;
	stop_machine(change_clocksource, clock, NULL);
	tick_clock_notify();
	return tk->tkr_mono.clock == clock ? 0 : -1;
}

Contributors
Person Tokens Prop Commits CommitProp
Martin Schwidefsky 23 38.98% 1 14.29%
Thomas Gleixner 20 33.90% 3 42.86%
John Stultz 14 23.73% 2 28.57%
Peter Zijlstra 2 3.39% 1 14.29%
Total 59 100.00% 7 100.00%

/**
 * getrawmonotonic64 - Returns the raw monotonic time in a timespec
 * @ts:         pointer to the timespec64 to be set
 *
 * Returns the raw monotonic time (completely un-modified by ntp)
 */


void getrawmonotonic64(struct timespec64 *ts)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned long seq;
	u64 nsecs;

	do {
		seq = read_seqcount_begin(&tk_core.seq);
		ts->tv_sec = tk->raw_sec;
		nsecs = timekeeping_get_ns(&tk->tkr_raw);

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

	ts->tv_nsec = 0;
	timespec64_add_ns(ts, nsecs);
}
Contributors
Person Tokens Prop Commits CommitProp
John Stultz 69 82.14% 6 60.00%
Thomas Gleixner 11 13.10% 3 30.00%
Peter Zijlstra 4 4.76% 1 10.00%
Total 84 100.00% 10 100.00%


EXPORT_SYMBOL(getrawmonotonic64);


/**
 * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
 */


int timekeeping_valid_for_hres(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned long seq;
	int ret;

	do {
		seq = read_seqcount_begin(&tk_core.seq);

		ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;

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

	return ret;
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 52 80.00% 2 28.57%
Thomas Gleixner 11 16.92% 3 42.86%
Li Zefan 1 1.54% 1 14.29%
Peter Zijlstra 1 1.54% 1 14.29%
Total 65 100.00% 7 100.00%

/**
 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
 */


u64 timekeeping_max_deferment(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned long seq;
	u64 ret;

	do {
		seq = read_seqcount_begin(&tk_core.seq);

		ret = tk->tkr_mono.clock->max_idle_ns;

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

	return ret;
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 40 63.49% 2 28.57%
Jon Hunter 11 17.46% 1 14.29%
Thomas Gleixner 11 17.46% 3 42.86%
Peter Zijlstra 1 1.59% 1 14.29%
Total 63 100.00% 7 100.00%

/**
 * read_persistent_clock -  Return time from the persistent clock.
 *
 * Weak dummy function for arches that do not yet support it.
 * Reads the time from the battery backed persistent clock.
 * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
 *
 *  XXX - Do be sure to remove it once all arches implement it.
 */


void __weak read_persistent_clock(struct timespec *ts)
{
	ts->tv_sec = 0;
	ts->tv_nsec = 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Martin Schwidefsky 14 60.87% 1 33.33%
Gideon Israel Dsouza 5 21.74% 1 33.33%
John Stultz 4 17.39% 1 33.33%
Total 23 100.00% 3 100.00%



void __weak read_persistent_clock64(struct timespec64 *ts64)
{
	struct timespec ts;

	read_persistent_clock(&ts);
	*ts64 = timespec_to_timespec64(ts);
}

Contributors
Person Tokens Prop Commits CommitProp
Xunlei Pang 29 100.00% 1 100.00%
Total 29 100.00% 1 100.00%

/**
 * read_boot_clock64 -  Return time of the system start.
 *
 * Weak dummy function for arches that do not yet support it.
 * Function to read the exact time the system has been started.
 * Returns a timespec64 with tv_sec=0 and tv_nsec=0 if unsupported.
 *
 *  XXX - Do be sure to remove it once all arches implement it.
 */


void __weak read_boot_clock64(struct timespec64 *ts)
{
	ts->tv_sec = 0;
	ts->tv_nsec = 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Martin Schwidefsky 16 69.57% 1 33.33%
Gideon Israel Dsouza 5 21.74% 1 33.33%
Xunlei Pang 2 8.70% 1 33.33%
Total 23 100.00% 3 100.00%

/* Flag for if timekeeping_resume() has injected sleeptime */

static bool sleeptime_injected;

/* Flag for if there is a persistent clock on this platform */

static bool persistent_clock_exists;

/*
 * timekeeping_init - Initializes the clocksource and common timekeeping values
 */


void __init timekeeping_init(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	struct clocksource *clock;
	unsigned long flags;
	struct timespec64 now, boot, tmp;

	read_persistent_clock64(&now);
	if (!timespec64_valid_strict(&now)) {
		pr_warn("WARNING: Persistent clock returned invalid value!\n"
			"         Check your CMOS/BIOS settings.\n");
		now.tv_sec = 0;
		now.tv_nsec = 0;
	} else if (now.tv_sec || now.tv_nsec)
		persistent_clock_exists = true;

	read_boot_clock64(&boot);
	if (!timespec64_valid_strict(&boot)) {
		pr_warn("WARNING: Boot clock returned invalid value!\n"
			"         Check your CMOS/BIOS settings.\n");
		boot.tv_sec = 0;
		boot.tv_nsec = 0;
	}

	raw_spin_lock_irqsave(&timekeeper_lock, flags);
	write_seqcount_begin(&tk_core.seq);
	ntp_init();

	clock = clocksource_default_clock();
	if (clock->enable)
		clock->enable(clock);
	tk_setup_internals(tk, clock);

	tk_set_xtime(tk, &now);
	tk->raw_sec = 0;
	if (boot.tv_sec == 0 && boot.tv_nsec == 0)
		boot = tk_xtime(tk);

	set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
	tk_set_wall_to_mono(tk, tmp);

	timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);

	write_seqcount_end(&tk_core.seq);
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 142 57.49% 10 37.04%
Martin Schwidefsky 52 21.05% 5 18.52%
Thomas Gleixner 32 12.96% 7 25.93%
Feng Tang 14 5.67% 1 3.70%
Magnus Damm 4 1.62% 1 3.70%
Xunlei Pang 3 1.21% 3 11.11%
Total 247 100.00% 27 100.00%

/* time in seconds when suspend began for persistent clock */

static struct timespec64 timekeeping_suspend_time;

/**
 * __timekeeping_inject_sleeptime - Internal function to add sleep interval
 * @delta: pointer to a timespec delta value
 *
 * Takes a timespec offset measuring a suspend interval and properly
 * adds the sleep offset to the timekeeping variables.
 */


static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
					   struct timespec64 *delta)
{
	if (!timespec64_valid_strict(delta)) {
		printk_deferred(KERN_WARNING
				"__timekeeping_inject_sleeptime: Invalid "
				"sleep delta value!\n");
		return;
	}
	tk_xtime_add(tk, delta);
	tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
	tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
	tk_debug_account_sleep_time(delta);
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 63 87.50% 8 72.73%
Colin Cross 5 6.94% 1 9.09%
Thomas Gleixner 4 5.56% 2 18.18%
Total 72 100.00% 11 100.00%

#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
/**
 * We have three kinds of time sources to use for sleep time
 * injection, the preference order is:
 * 1) non-stop clocksource
 * 2) persistent clock (ie: RTC accessible when irqs are off)
 * 3) RTC
 *
 * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
 * If system has neither 1) nor 2), 3) will be used finally.
 *
 *
 * If timekeeping has injected sleeptime via either 1) or 2),
 * 3) becomes needless, so in this case we don't need to call
 * rtc_resume(), and this is what timekeeping_rtc_skipresume()
 * means.
 */


bool timekeeping_rtc_skipresume(void)
{
	return sleeptime_injected;
}

Contributors
Person Tokens Prop Commits CommitProp
Xunlei Pang 10 100.00% 1 100.00%
Total 10 100.00% 1 100.00%

/**
 * 1) can be determined whether to use or not only when doing
 * timekeeping_resume() which is invoked after rtc_suspend(),
 * so we can't skip rtc_suspend() surely if system has 1).
 *
 * But if system has 2), 2) will definitely be used, so in this
 * case we don't need to call rtc_suspend(), and this is what
 * timekeeping_rtc_skipsuspend() means.
 */


bool timekeeping_rtc_skipsuspend(void)
{
	return persistent_clock_exists;
}

Contributors
Person Tokens Prop Commits CommitProp
Xunlei Pang 10 100.00% 1 100.00%
Total 10 100.00% 1 100.00%

/**
 * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
 * @delta: pointer to a timespec64 delta value
 *
 * This hook is for architectures that cannot support read_persistent_clock64
 * because their RTC/persistent clock is only accessible when irqs are enabled.
 * and also don't have an effective nonstop clocksource.
 *
 * This function should only be called by rtc_resume(), and allows
 * a suspend offset to be injected into the timekeeping values.
 */


void timekeeping_inject_sleeptime64(struct timespec64 *delta)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned long flags;

	raw_spin_lock_irqsave(&timekeeper_lock, flags);
	write_seqcount_begin(&tk_core.seq);

	timekeeping_forward_now(tk);

	__timekeeping_inject_sleeptime(tk, delta);

	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);

	write_seqcount_end(&tk_core.seq);
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);

	/* signal hrtimers about time change */
	clock_was_set();
}
Contributors
Person Tokens Prop Commits CommitProp
John Stultz 52 62.65% 5 41.67%
Thomas Gleixner 23 27.71% 4 33.33%
David Vrabel 5 6.02% 2 16.67%
Xunlei Pang 3 3.61% 1 8.33%
Total 83 100.00% 12 100.00%

#endif

/**
 * timekeeping_resume - Resumes the generic timekeeping subsystem.
 */


void timekeeping_resume(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	struct clocksource *clock = tk->tkr_mono.clock;
	unsigned long flags;
	struct timespec64 ts_new, ts_delta;
	u64 cycle_now;

	sleeptime_injected = false;
	read_persistent_clock64(&ts_new);

	clockevents_resume();
	clocksource_resume();

	raw_spin_lock_irqsave(&timekeeper_lock, flags);
	write_seqcount_begin(&tk_core.seq);

	/*
         * After system resumes, we need to calculate the suspended time and
         * compensate it for the OS time. There are 3 sources that could be
         * used: Nonstop clocksource during suspend, persistent clock and rtc
         * device.
         *
         * One specific platform may have 1 or 2 or all of them, and the
         * preference will be:
         *      suspend-nonstop clocksource -> persistent clock -> rtc
         * The less preferred source will only be tried if there is no better
         * usable source. The rtc part is handled separately in rtc core code.
         */
	cycle_now = tk_clock_read(&tk->tkr_mono);
	if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
		cycle_now > tk->tkr_mono.cycle_last) {
		u64 nsec, cyc_delta;

		cyc_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last,
					      tk->tkr_mono.mask);
		nsec = mul_u64_u32_shr(cyc_delta, clock->mult, clock->shift);
		ts_delta = ns_to_timespec64(nsec);
		sleeptime_injected = true;
	} else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
		ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
		sleeptime_injected = true;
	}

	if (sleeptime_injected)
		__timekeeping_inject_sleeptime(tk, &ts_delta);

	/* Re-base the last cycle value */
	tk->tkr_mono.cycle_last = cycle_now;
	tk->tkr_raw.cycle_last  = cycle_now;

	tk->ntp_error = 0;
	timekeeping_suspended = 0;
	timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
	write_seqcount_end(&tk_core.seq);
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);

	touch_softlockup_watchdog();

	tick_resume();
	hrtimers_resume();
}

Contributors
Person Tokens Prop Commits CommitProp
Feng Tang 79 30.86% 1 2.86%
Thomas Gleixner 63 24.61% 14 40.00%
John Stultz 63 24.61% 8 22.86%
Martin Schwidefsky 20 7.81% 2 5.71%
Peter Zijlstra 14 5.47% 2 5.71%
Xunlei Pang 7 2.73% 2 5.71%
Rafael J. Wysocki 5 1.95% 2 5.71%
David Vrabel 3 1.17% 2 5.71%
Ingo Molnar 1 0.39% 1 2.86%
Tomas Janousek 1 0.39% 1 2.86%
Total 256 100.00% 35 100.00%



int timekeeping_suspend(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned long flags;
	struct timespec64		delta, delta_delta;
	static struct timespec64	old_delta;

	read_persistent_clock64(&timekeeping_suspend_time);

	/*
         * On some systems the persistent_clock can not be detected at
         * timekeeping_init by its return value, so if we see a valid
         * value returned, update the persistent_clock_exists flag.
         */
	if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
		persistent_clock_exists = true;

	raw_spin_lock_irqsave(&timekeeper_lock, flags);
	write_seqcount_begin(&tk_core.seq);
	timekeeping_forward_now(tk);
	timekeeping_suspended = 1;

	if (persistent_clock_exists) {
		/*
                 * To avoid drift caused by repeated suspend/resumes,
                 * which each can add ~1 second drift error,
                 * try to compensate so the difference in system time
                 * and persistent_clock time stays close to constant.
                 */
		delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
		delta_delta = timespec64_sub(delta, old_delta);
		if (abs(delta_delta.tv_sec) >= 2) {
			/*
                         * if delta_delta is too large, assume time correction
                         * has occurred and set old_delta to the current delta.
                         */
			old_delta = delta;
		} else {
			/* Otherwise try to adjust old_system to compensate */
			timekeeping_suspend_time =
				timespec64_add(timekeeping_suspend_time, delta_delta);
		}
	}

	timekeeping_update(tk, TK_MIRROR);
	halt_fast_timekeeper(tk);
	write_seqcount_end(&tk_core.seq);
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);

	tick_suspend();
	clocksource_suspend();
	clockevents_suspend();

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 110 62.15% 9 36.00%
Thomas Gleixner 26 14.69% 6 24.00%
Zoran Markovic 14 7.91% 1 4.00%
Xunlei Pang 10 5.65% 3 12.00%
Rafael J. Wysocki 9 5.08% 3 12.00%
Martin Schwidefsky 5 2.82% 2 8.00%
Magnus Damm 3 1.69% 1 4.00%
Total 177 100.00% 25 100.00%

/* sysfs resume/suspend bits for timekeeping */

static struct syscore_ops timekeeping_syscore_ops = {
	.resume		= timekeeping_resume,
	.suspend	= timekeeping_suspend,
};



static int __init timekeeping_init_ops(void)
{
	register_syscore_ops(&timekeeping_syscore_ops);
	return 0;
}
Contributors
Person Tokens Prop Commits CommitProp
John Stultz 14 77.78% 1 50.00%
Rafael J. Wysocki 4 22.22% 1 50.00%
Total 18 100.00% 2 100.00%


device_initcall(timekeeping_init_ops);

/*
 * Apply a multiplier adjustment to the timekeeper
 */


static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
							 s64 offset,
							 bool negative,
							 int adj_scale)
{
	s64 interval = tk->cycle_interval;
	s32 mult_adj = 1;

	if (negative) {
		mult_adj = -mult_adj;
		interval = -interval;
		offset  = -offset;
	}
	mult_adj <<= adj_scale;
	interval <<= adj_scale;
	offset <<= adj_scale;

	/*
         * So the following can be confusing.
         *
         * To keep things simple, lets assume mult_adj == 1 for now.
         *
         * When mult_adj != 1, remember that the interval and offset values
         * have been appropriately scaled so the math is the same.
         *
         * The basic idea here is that we're increasing the multiplier
         * by one, this causes the xtime_interval to be incremented by
         * one cycle_interval. This is because:
         *      xtime_interval = cycle_interval * mult
         * So if mult is being incremented by one:
         *      xtime_interval = cycle_interval * (mult + 1)
         * Its the same as:
         *      xtime_interval = (cycle_interval * mult) + cycle_interval
         * Which can be shortened to:
         *      xtime_interval += cycle_interval
         *
         * So offset stores the non-accumulated cycles. Thus the current
         * time (in shifted nanoseconds) is:
         *      now = (offset * adj) + xtime_nsec
         * Now, even though we're adjusting the clock frequency, we have
         * to keep time consistent. In other words, we can't jump back
         * in time, and we also want to avoid jumping forward in time.
         *
         * So given the same offset value, we need the time to be the same
         * both before and after the freq adjustment.
         *      now = (offset * adj_1) + xtime_nsec_1
         *      now = (offset * adj_2) + xtime_nsec_2
         * So:
         *      (offset * adj_1) + xtime_nsec_1 =
         *              (offset * adj_2) + xtime_nsec_2
         * And we know:
         *      adj_2 = adj_1 + 1
         * So:
         *      (offset * adj_1) + xtime_nsec_1 =
         *              (offset * (adj_1+1)) + xtime_nsec_2
         *      (offset * adj_1) + xtime_nsec_1 =
         *              (offset * adj_1) + offset + xtime_nsec_2
         * Canceling the sides:
         *      xtime_nsec_1 = offset + xtime_nsec_2
         * Which gives us:
         *      xtime_nsec_2 = xtime_nsec_1 - offset
         * Which simplfies to:
         *      xtime_nsec -= offset
         *
         * XXX - TODO: Doc ntp_error calculation.
         */
	if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
		/* NTP adjustment caused clocksource mult overflow */
		WARN_ON_ONCE(1);
		return;
	}

	tk->tkr_mono.mult += mult_adj;
	tk->xtime_interval += interval;
	tk->tkr_mono.xtime_nsec -= offset;
	tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 109 82.58% 4 66.67%
Xunlei Pang 20 15.15% 1 16.67%
Peter Zijlstra 3 2.27% 1 16.67%
Total 132 100.00% 6 100.00%

/*
 * Calculate the multiplier adjustment needed to match the frequency
 * specified by NTP
 */


static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
							s64 offset)
{
	s64 interval = tk->cycle_interval;
	s64 xinterval = tk->xtime_interval;
	u32 base = tk->tkr_mono.clock->mult;
	u32 max = tk->tkr_mono.clock->maxadj;
	u32 cur_adj = tk->tkr_mono.mult;
	s64 tick_error;
	bool negative;
	u32 adj_scale;

	/* Remove any current error adj from freq calculation */
	if (tk->ntp_err_mult)
		xinterval -= tk->cycle_interval;

	tk->ntp_tick = ntp_tick_length();

	/* Calculate current error per tick */
	tick_error = ntp_tick_length() >> tk->ntp_error_shift;
	tick_error -= (xinterval + tk->xtime_remainder);

	/* Don't worry about correcting it if its small */
	if (likely((tick_error >= 0) && (tick_error <= interval)))
		return;

	/* preserve the direction of correction */
	negative = (tick_error < 0);

	/* If any adjustment would pass the max, just return */
	if (negative && (cur_adj - 1) <= (base - max))
		return;
	if (!negative && (cur_adj + 1) >= (base + max))
		return;
	/*
         * Sort out the magnitude of the correction, but
         * avoid making so large a correction that we go
         * over the max adjustment.
         */
	adj_scale = 0;
	tick_error = abs(tick_error);
	while (tick_error > interval) {
		u32 adj = 1 << (adj_scale + 1);

		/* Check if adjustment gets us within 1 unit from the max */
		if (negative && (cur_adj - adj) <= (base - max))
			break;
		if (!negative && (cur_adj + adj) >= (base + max))
			break;

		adj_scale++;
		tick_error >>= 1;
	}

	/* scale the corrections */
	timekeeping_apply_adjustment(tk, offset, negative, adj_scale);
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 257 99.23% 5 71.43%
Andrew Morton 1 0.39% 1 14.29%
Martin Schwidefsky 1 0.39% 1 14.29%
Total 259 100.00% 7 100.00%

/*
 * Adjust the timekeeper's multiplier to the correct frequency
 * and also to reduce the accumulated error value.
 */


static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
{
	/* Correct for the current frequency error */
	timekeeping_freqadjust(tk, offset);

	/* Next make a small adjustment to fix any cumulative error */
	if (!tk->ntp_err_mult && (tk->ntp_error > 0)) {
		tk->ntp_err_mult = 1;
		timekeeping_apply_adjustment(tk, offset, 0, 0);
	} else if (tk->ntp_err_mult && (tk->ntp_error <= 0)) {
		/* Undo any existing error adjustment */
		timekeeping_apply_adjustment(tk, offset, 1, 0);
		tk->ntp_err_mult = 0;
	}

	if (unlikely(tk->tkr_mono.clock->maxadj &&
		(abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
			> tk->tkr_mono.clock->maxadj))) {
		printk_once(KERN_WARNING
			"Adjusting %s more than 11%% (%ld vs %ld)\n",
			tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
			(long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
	}

	/*
         * It may be possible that when we entered this function, xtime_nsec
         * was very small.  Further, if we're slightly speeding the clocksource
         * in the code above, its possible the required corrective factor to
         * xtime_nsec could cause it to underflow.
         *
         * Now, since we already accumulated the second, cannot simply roll
         * the accumulated second back, since the NTP subsystem has been
         * notified via second_overflow. So instead we push xtime_nsec forward
         * by the amount we underflowed, and add that amount into the error.
         *
         * We'll correct this error next time through this function, when
         * xtime_nsec is not as small.
         */
	if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
		s64 neg = -(s64)tk->tkr_mono.xtime_nsec;
		tk->tkr_mono.xtime_nsec = 0;
		tk->ntp_error += neg << tk->ntp_error_shift;
	}
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 197 87.17% 6 60.00%
Thomas Gleixner 11 4.87% 1 10.00%
Peter Zijlstra 11 4.87% 1 10.00%
Xunlei Pang 5 2.21% 1 10.00%
Ingo Molnar 2 0.88% 1 10.00%
Total 226 100.00% 10 100.00%

/**
 * accumulate_nsecs_to_secs - Accumulates nsecs into secs
 *
 * Helper function that accumulates the nsecs greater than a second
 * from the xtime_nsec field to the xtime_secs field.
 * It also calls into the NTP code to handle leapsecond processing.
 *
 */


static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
{
	u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
	unsigned int clock_set = 0;

	while (tk->tkr_mono.xtime_nsec >= nsecps) {
		int leap;

		tk->tkr_mono.xtime_nsec -= nsecps;
		tk->xtime_sec++;

		/* Figure out if its a leap sec and apply if needed */
		leap = second_overflow(tk->xtime_sec);
		if (unlikely(leap)) {
			struct timespec64 ts;

			tk->xtime_sec += leap;

			ts.tv_sec = leap;
			ts.tv_nsec = 0;
			tk_set_wall_to_mono(tk,
				timespec64_sub(tk->wall_to_monotonic, ts));

			__timekeeping_set_tai_offset(tk, tk->tai_offset - leap);

			clock_set = TK_CLOCK_WAS_SET;
		}
	}
	return clock_set;
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 106 79.10% 7 63.64%
David Vrabel 12 8.96% 1 9.09%
Martin Schwidefsky 10 7.46% 1 9.09%
Peter Zijlstra 3 2.24% 1 9.09%
Thomas Gleixner 3 2.24% 1 9.09%
Total 134 100.00% 11 100.00%

/**
 * logarithmic_accumulation - shifted accumulation of cycles
 *
 * This functions accumulates a shifted interval of cycles into
 * into a shifted interval nanoseconds. Allows for O(log) accumulation
 * loop.
 *
 * Returns the unconsumed cycles.
 */


static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
				    u32 shift, unsigned int *clock_set)
{
	u64 interval = tk->cycle_interval << shift;
	u64 snsec_per_sec;

	/* If the offset is smaller than a shifted interval, do nothing */
	if (offset < interval)
		return offset;

	/* Accumulate one shifted interval */
	offset -= interval;
	tk->tkr_mono.cycle_last += interval;
	tk->tkr_raw.cycle_last  += interval;

	tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
	*clock_set |= accumulate_nsecs_to_secs(tk);

	/* Accumulate raw time */
	tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
	snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
	while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
		tk->tkr_raw.xtime_nsec -= snsec_per_sec;
		tk->raw_sec++;
	}

	/* Accumulate error between NTP and clock interval */
	tk->ntp_error += tk->ntp_tick << shift;
	tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
						(tk->ntp_error_shift + shift);

	return offset;
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 128 74.42% 10 47.62%
Thomas Gleixner 16 9.30% 3 14.29%
Peter Zijlstra 10 5.81% 2 9.52%
Roman Zippel 5 2.91% 1 4.76%
Jason Wessel 5 2.91% 1 4.76%
Kasper Pedersen 4 2.33% 1 4.76%
Martin Schwidefsky 3 1.74% 2 9.52%
Zhen Lei 1 0.58% 1 4.76%
Total 172 100.00% 21 100.00%

/**
 * update_wall_time - Uses the current clocksource to increment the wall time
 *
 */


void update_wall_time(void)
{
	struct timekeeper *real_tk = &tk_core.timekeeper;
	struct timekeeper *tk = &shadow_timekeeper;
	u64 offset;
	int shift = 0, maxshift;
	unsigned int clock_set = 0;
	unsigned long flags;

	raw_spin_lock_irqsave(&timekeeper_lock, flags);

	/* Make sure we're fully resumed: */
	if (unlikely(timekeeping_suspended))
		goto out;

#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
	offset = real_tk->cycle_interval;
#else
	offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
				   tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
#endif

	/* Check if there's really nothing to do */
	if (offset < real_tk->cycle_interval)
		goto out;

	/* Do some additional sanity checking */
	timekeeping_check_update(tk, offset);

	/*
         * With NO_HZ we may have to accumulate many cycle_intervals
         * (think "ticks") worth of time at once. To do this efficiently,
         * we calculate the largest doubling multiple of cycle_intervals
         * that is smaller than the offset.  We then accumulate that
         * chunk in one go, and then try to consume the next smaller
         * doubled multiple.
         */
	shift = ilog2(offset) - ilog2(tk->cycle_interval);
	shift = max(0, shift);
	/* Bound shift to one less than what overflows tick_length */
	maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
	shift = min(shift, maxshift);
	while (offset >= tk->cycle_interval) {
		offset = logarithmic_accumulation(tk, offset, shift,
							&clock_set);
		if (offset < tk->cycle_interval<<shift)
			shift--;
	}

	/* correct the clock when NTP error is too big */
	timekeeping_adjust(tk, offset);

	/*
         * Finally, make sure that after the rounding
         * xtime_nsec isn't larger than NSEC_PER_SEC
         */
	clock_set |= accumulate_nsecs_to_secs(tk);

	write_seqcount_begin(&tk_core.seq);
	/*
         * Update the real timekeeper.
         *
         * We could avoid this memcpy by switching pointers, but that
         * requires changes to all other timekeeper usage sites as
         * well, i.e. move the timekeeper pointer getter into the
         * spinlocked/seqcount protected sections. And we trade this
         * memcpy under the tk_core.seq against one before we start
         * updating.
         */
	timekeeping_update(tk, clock_set);
	memcpy(real_tk, tk, sizeof(*tk));
	/* The memcpy must come last. Do not put anything here! */
	write_seqcount_end(&tk_core.seq);
out:
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
	if (clock_set)
		/* Have to call _delayed version, since in irq context*/
		clock_was_set_delayed();
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 215 75.97% 19 55.88%
Thomas Gleixner 58 20.49% 10 29.41%
Peter Zijlstra 3 1.06% 1 2.94%
David Vrabel 3 1.06% 1 2.94%
Jim Cromie 2 0.71% 1 2.94%
Stafford Horne 1 0.35% 1 2.94%
Martin Schwidefsky 1 0.35% 1 2.94%
Total 283 100.00% 34 100.00%

/**
 * getboottime64 - Return the real time of system boot.
 * @ts:         pointer to the timespec64 to be set
 *
 * Returns the wall-time of boot in a timespec64.
 *
 * This is based on the wall_to_monotonic offset and the total suspend
 * time. Calls to settimeofday will affect the value returned (which
 * basically means that however wrong your real time clock is at boot time,
 * you get the right time here).
 */


void getboottime64(struct timespec64 *ts)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);

	*ts = ktime_to_timespec64(t);
}
Contributors
Person Tokens Prop Commits CommitProp
Thomas Gleixner 14 33.33% 2 28.57%
John Stultz 14 33.33% 2 28.57%
Tomas Janousek 11 26.19% 1 14.29%
Hiroshi Shimamoto 2 4.76% 1 14.29%
Martin Schwidefsky 1 2.38% 1 14.29%
Total 42 100.00% 7 100.00%


EXPORT_SYMBOL_GPL(getboottime64);



unsigned long get_seconds(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;

	return tk->xtime_sec;
}
Contributors
Person Tokens Prop Commits CommitProp
John Stultz 21 91.30% 4 80.00%
Thomas Gleixner 2 8.70% 1 20.00%
Total 23 100.00% 5 100.00%


EXPORT_SYMBOL(get_seconds);



struct timespec __current_kernel_time(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;

	return timespec64_to_timespec(tk_xtime(tk));
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 25 92.59% 4 80.00%
Thomas Gleixner 2 7.41% 1 20.00%
Total 27 100.00% 5 100.00%



struct timespec64 current_kernel_time64(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	struct timespec64 now;
	unsigned long seq;

	do {
		seq = read_seqcount_begin(&tk_core.seq);

		now = tk_xtime(tk);
	} while (read_seqcount_retry(&tk_core.seq, seq));

	return now;
}
Contributors
Person Tokens Prop Commits CommitProp
John Stultz 50 80.65% 4 57.14%
Thomas Gleixner 10 16.13% 2 28.57%
Baolin Wang 2 3.23% 1 14.29%
Total 62 100.00% 7 100.00%


EXPORT_SYMBOL(current_kernel_time64);



struct timespec64 get_monotonic_coarse64(void)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	struct timespec64 now, mono;
	unsigned long seq;

	do {
		seq = read_seqcount_begin(&tk_core.seq);

		now = tk_xtime(tk);
		mono = tk->wall_to_monotonic;
	} while (read_seqcount_retry(&tk_core.seq, seq));

	set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
				now.tv_nsec + mono.tv_nsec);

	return now;
}
Contributors
Person Tokens Prop Commits CommitProp
John Stultz 82 89.13% 5 71.43%
Thomas Gleixner 10 10.87% 2 28.57%
Total 92 100.00% 7 100.00%


EXPORT_SYMBOL(get_monotonic_coarse64);

/*
 * Must hold jiffies_lock
 */


void do_timer(unsigned long ticks)
{
	jiffies_64 += ticks;
	calc_global_load(ticks);
}

Contributors
Person Tokens Prop Commits CommitProp
Torben Hohn 18 100.00% 1 100.00%
Total 18 100.00% 1 100.00%

/**
 * ktime_get_update_offsets_now - hrtimer helper
 * @cwsseq:     pointer to check and store the clock was set sequence number
 * @offs_real:  pointer to storage for monotonic -> realtime offset
 * @offs_boot:  pointer to storage for monotonic -> boottime offset
 * @offs_tai:   pointer to storage for monotonic -> clock tai offset
 *
 * Returns current monotonic time and updates the offsets if the
 * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
 * different.
 *
 * Called from hrtimer_interrupt() or retrigger_next_event()
 */


ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
				     ktime_t *offs_boot, ktime_t *offs_tai)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned int seq;
	ktime_t base;
	u64 nsecs;

	do {
		seq = read_seqcount_begin(&tk_core.seq);

		base = tk->tkr_mono.base;
		nsecs = timekeeping_get_ns(&tk->tkr_mono);
		base = ktime_add_ns(base, nsecs);

		if (*cwsseq != tk->clock_was_set_seq) {
			*cwsseq = tk->clock_was_set_seq;
			*offs_real = tk->offs_real;
			*offs_boot = tk->offs_boot;
			*offs_tai = tk->offs_tai;
		}

		/* Handle leapsecond insertion adjustments */
		if (unlikely(base >= tk->next_leap_ktime))
			*offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));

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

	return base;
}

Contributors
Person Tokens Prop Commits CommitProp
Thomas Gleixner 96 57.83% 7 53.85%
John Stultz 67 40.36% 5 38.46%
Peter Zijlstra 3 1.81% 1 7.69%
Total 166 100.00% 13 100.00%

/**
 * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex
 */


static int timekeeping_validate_timex(struct timex *txc)
{
	if (txc->modes & ADJ_ADJTIME) {
		/* singleshot must not be used with any other mode bits */
		if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
			return -EINVAL;
		if (!(txc->modes & ADJ_OFFSET_READONLY) &&
		    !capable(CAP_SYS_TIME))
			return -EPERM;
	} else {
		/* In order to modify anything, you gotta be super-user! */
		if (txc->modes && !capable(CAP_SYS_TIME))
			return -EPERM;
		/*
                 * if the quartz is off by more than 10% then
                 * something is VERY wrong!
                 */
		if (txc->modes & ADJ_TICK &&
		    (txc->tick <  900000/USER_HZ ||
		     txc->tick > 1100000/USER_HZ))
			return -EINVAL;
	}

	if (txc->modes & ADJ_SETOFFSET) {
		/* In order to inject time, you gotta be super-user! */
		if (!capable(CAP_SYS_TIME))
			return -EPERM;

		/*
                 * Validate if a timespec/timeval used to inject a time
                 * offset is valid.  Offsets can be postive or negative, so
                 * we don't check tv_sec. The value of the timeval/timespec
                 * is the sum of its fields,but *NOTE*:
                 * The field tv_usec/tv_nsec must always be non-negative and
                 * we can't have more nanoseconds/microseconds than a second.
                 */
		if (txc->time.tv_usec < 0)
			return -EINVAL;

		if (txc->modes & ADJ_NANO) {
			if (txc->time.tv_usec >= NSEC_PER_SEC)
				return -EINVAL;
		} else {
			if (txc->time.tv_usec >= USEC_PER_SEC)
				return -EINVAL;
		}
	}

	/*
         * Check for potential multiplication overflows that can
         * only happen on 64-bit systems:
         */
	if ((txc->modes & ADJ_FREQUENCY) && (BITS_PER_LONG == 64)) {
		if (LLONG_MIN / PPM_SCALE > txc->freq)
			return -EINVAL;
		if (LLONG_MAX / PPM_SCALE < txc->freq)
			return -EINVAL;
	}

	return 0;
}


Contributors
Person Tokens Prop Commits CommitProp
Arnd Bergmann 238 100.00% 2 100.00%
Total 238 100.00% 2 100.00%

/**
 * do_adjtimex() - Accessor function to NTP __do_adjtimex function
 */


int do_adjtimex(struct timex *txc)
{
	struct timekeeper *tk = &tk_core.timekeeper;
	unsigned long flags;
	struct timespec64 ts;
	s32 orig_tai, tai;
	int ret;

	/* Validate the data before disabling interrupts */
	ret = timekeeping_validate_timex(txc);
	if (ret)
		return ret;

	if (txc->modes & ADJ_SETOFFSET) {
		struct timespec64 delta;
		delta.tv_sec  = txc->time.tv_sec;
		delta.tv_nsec = txc->time.tv_usec;
		if (!(txc->modes & ADJ_NANO))
			delta.tv_nsec *= 1000;
		ret = timekeeping_inject_offset(&delta);
		if (ret)
			return ret;
	}

	getnstimeofday64(&ts);

	raw_spin_lock_irqsave(&timekeeper_lock, flags);
	write_seqcount_begin(&tk_core.seq);

	orig_tai = tai = tk->tai_offset;
	ret = __do_adjtimex(txc, &ts, &tai);

	if (tai != orig_tai) {
		__timekeeping_set_tai_offset(tk, tai);
		timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
	}
	tk_update_leap_state(tk);

	write_seqcount_end(&tk_core.seq);
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);

	if (tai != orig_tai)
		clock_was_set();

	ntp_notify_cmos_timer();

	return ret;
}

Contributors
Person Tokens Prop Commits CommitProp
John Stultz 204 92.73% 12 75.00%
Thomas Gleixner 9 4.09% 2 12.50%
David Vrabel 5 2.27% 1 6.25%
Arnd Bergmann 2 0.91% 1 6.25%
Total 220 100.00% 16 100.00%

#ifdef CONFIG_NTP_PPS
/**
 * hardpps() - Accessor function to NTP __hardpps function
 */


void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
{
	unsigned long flags;

	raw_spin_lock_irqsave(&timekeeper_lock, flags);
	write_seqcount_begin(&tk_core.seq);

	__hardpps(phase_ts, raw_ts);

	write_seqcount_end(&tk_core.seq);
	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
}
Contributors
Person Tokens Prop Commits CommitProp
John Stultz 52 86.67% 2 50.00%
Thomas Gleixner 6 10.00% 1 25.00%
Arnd Bergmann 2 3.33% 1 25.00%
Total 60 100.00% 4 100.00%


EXPORT_SYMBOL(hardpps);
#endif /* CONFIG_NTP_PPS */

/**
 * xtime_update() - advances the timekeeping infrastructure
 * @ticks:      number of ticks, that have elapsed since the last call.
 *
 * Must be called with interrupts disabled.
 */


void xtime_update(unsigned long ticks)
{
	write_seqlock(&jiffies_lock);
	do_timer(ticks);
	write_sequnlock(&jiffies_lock);
	update_wall_time();
}
Contributors
Person Tokens Prop Commits CommitProp
Torben Hohn 24 82.76% 1 33.33%
John Stultz 5 17.24% 2 66.67%
Total 29 100.00% 3 100.00%

Overall Contributors
Person Tokens Prop Commits CommitProp
John Stultz 3804 44.21% 79 36.57%
Thomas Gleixner 1485 17.26% 48 22.22%
Christopher S. Hall 1042 12.11% 5 2.31%
Martin Schwidefsky 434 5.04% 10 4.63%
Arnd Bergmann 315 3.66% 4 1.85%
Peter Zijlstra 292 3.39% 6 2.78%
Heena Sirwani 157 1.82% 2 0.93%
Marcelo Tosatti 141 1.64% 1 0.46%
Xunlei Pang 137 1.59% 10 4.63%
Feng Tang 93 1.08% 2 0.93%
Prarit Bhargava 91 1.06% 1 0.46%
Rafael J. Wysocki 81 0.94% 4 1.85%
Harald Geyer 77 0.89% 1 0.46%
David Vrabel 71 0.83% 2 0.93%
Wang YanQing 44 0.51% 1 0.46%
Torben Hohn 43 0.50% 2 0.93%
Joel Fernandes 37 0.43% 1 0.46%
Kees Cook 35 0.41% 1 0.46%
Stephen Warren 29 0.34% 1 0.46%
Magnus Damm 24 0.28% 2 0.93%
Roman Zippel 23 0.27% 1 0.46%
DengChao 23 0.27% 1 0.46%
Kasper Pedersen 16 0.19% 1 0.46%
Zoran Markovic 14 0.16% 1 0.46%
Gideon Israel Dsouza 13 0.15% 1 0.46%
Tomas Janousek 12 0.14% 1 0.46%
Jon Hunter 11 0.13% 1 0.46%
Ingo Molnar 11 0.13% 5 2.31%
Colin Cross 8 0.09% 1 0.46%
Grégor Boirie 5 0.06% 1 0.46%
Jason Wessel 5 0.06% 1 0.46%
Jason (Hui) Wang 4 0.05% 1 0.46%
Baolin Wang 3 0.03% 1 0.46%
Andreas Schwab 3 0.03% 1 0.46%
Alexey Dobriyan 3 0.03% 1 0.46%
Jim Cromie 2 0.02% 1 0.46%
Hiroshi Shimamoto 2 0.02% 1 0.46%
Li Zefan 2 0.02% 1 0.46%
Zhen Lei 2 0.02% 1 0.46%
Yijing Wang 1 0.01% 1 0.46%
Robert P. J. Day 1 0.01% 1 0.46%
Stafford Horne 1 0.01% 1 0.46%
Richard Cochran 1 0.01% 1 0.46%
Andrew Morton 1 0.01% 1 0.46%
Stephen Boyd 1 0.01% 1 0.46%
H Hartley Sweeten 1 0.01% 1 0.46%
Masanari Iida 1 0.01% 1 0.46%
Fengguang Wu 1 0.01% 1 0.46%
Geert Uytterhoeven 1 0.01% 1 0.46%
Total 8604 100.00% 216 100.00%
Directory: kernel/time

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.
Person	Tokens	Prop	Commits	CommitProp
Prarit Bhargava	14	100.00%	1	100.00%
Total	14	100.00%	1	100.00%
cregit-Linux how code gets into the kernel

Release 4.15 kernel/time/timekeeping.c

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