v4.19.13 snapshot.
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
new file mode 100644
index 0000000..f3b22f4
--- /dev/null
+++ b/kernel/time/timekeeping.c
@@ -0,0 +1,2422 @@
+/*
+ * 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/sched/clock.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)
+
+enum timekeeping_adv_mode {
+ /* Update timekeeper when a tick has passed */
+ TK_ADV_TICK,
+
+ /* Update timekeeper on a direct frequency change */
+ TK_ADV_FREQ
+};
+
+/*
+ * 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;
+}
+
+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++;
+ }
+}
+
+static inline struct timespec64 tk_xtime(const 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;
+}
+
+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;
+}
+
+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);
+}
+
+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));
+}
+
+static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
+{
+ tk->offs_boot = ktime_add(tk->offs_boot, delta);
+}
+
+/*
+ * 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(const struct tk_read_base *tkr)
+{
+ struct clocksource *clock = READ_ONCE(tkr->clock);
+
+ return clock->read(clock);
+}
+
+#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;
+ }
+}
+
+static inline u64 timekeeping_get_delta(const 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;
+}
+#else
+static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset)
+{
+}
+static inline u64 timekeeping_get_delta(const 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;
+}
+#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;
+ tk->skip_second_overflow = 0;
+}
+
+/* Timekeeper helper functions. */
+
+#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
+static u32 default_arch_gettimeoffset(void) { return 0; }
+u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
+#else
+static inline u32 arch_gettimeoffset(void) { return 0; }
+#endif
+
+static inline u64 timekeeping_delta_to_ns(const 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();
+}
+
+static inline u64 timekeeping_get_ns(const struct tk_read_base *tkr)
+{
+ u64 delta;
+
+ delta = timekeeping_get_delta(tkr);
+ return timekeeping_delta_to_ns(tkr, delta);
+}
+
+static inline u64 timekeeping_cycles_to_ns(const 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);
+}
+
+/**
+ * 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(const 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));
+}
+
+/**
+ * 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;
+}
+
+u64 ktime_get_mono_fast_ns(void)
+{
+ return __ktime_get_fast_ns(&tk_fast_mono);
+}
+EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
+
+u64 ktime_get_raw_fast_ns(void)
+{
+ return __ktime_get_fast_ns(&tk_fast_raw);
+}
+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));
+}
+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;
+}
+
+/**
+ * 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);
+}
+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(const struct timekeeper *tk)
+{
+ static struct tk_read_base tkr_dummy;
+ const 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);
+}
+
+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);
+}
+
+/**
+ * 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;
+}
+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;
+}
+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);
+}
+
+/*
+ * 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);
+}
+
+/* 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));
+}
+
+/**
+ * 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);
+}
+
+/**
+ * ktime_get_real_ts64 - Returns the time of day in a timespec64.
+ * @ts: pointer to the timespec to be set
+ *
+ * Returns the time of day in a timespec64 (WARN if suspended).
+ */
+void ktime_get_real_ts64(struct timespec64 *ts)
+{
+ struct timekeeper *tk = &tk_core.timekeeper;
+ unsigned long seq;
+ u64 nsecs;
+
+ WARN_ON(timekeeping_suspended);
+
+ 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);
+}
+EXPORT_SYMBOL(ktime_get_real_ts64);
+
+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);
+}
+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;
+}
+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);
+
+}
+EXPORT_SYMBOL_GPL(ktime_get_with_offset);
+
+ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs)
+{
+ struct timekeeper *tk = &tk_core.timekeeper;
+ unsigned int seq;
+ ktime_t base, *offset = offsets[offs];
+
+ WARN_ON(timekeeping_suspended);
+
+ do {
+ seq = read_seqcount_begin(&tk_core.seq);
+ base = ktime_add(tk->tkr_mono.base, *offset);
+
+ } while (read_seqcount_retry(&tk_core.seq, seq));
+
+ return base;
+
+}
+EXPORT_SYMBOL_GPL(ktime_get_coarse_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;
+}
+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);
+}
+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);
+}
+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);
+
+/**
+ * __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;
+}
+
+/**
+ * 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);
+}
+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;
+}
+
+/**
+ * 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;
+}
+
+/*
+ * 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;
+}
+
+/**
+ * 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;
+}
+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;
+}
+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;
+}
+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(const 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;
+}
+
+/*
+ * 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);
+ }
+}
+
+/**
+ * __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));
+}
+
+/**
+ * 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;
+}
+
+/**
+ * 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;
+}
+
+/**
+ * ktime_get_raw_ts64 - 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 ktime_get_raw_ts64(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);
+}
+EXPORT_SYMBOL(ktime_get_raw_ts64);
+
+
+/**
+ * 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;
+}
+
+/**
+ * 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;
+}
+
+/**
+ * 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;
+}
+
+void __weak read_persistent_clock64(struct timespec64 *ts64)
+{
+ struct timespec ts;
+
+ read_persistent_clock(&ts);
+ *ts64 = timespec_to_timespec64(ts);
+}
+
+/**
+ * read_persistent_wall_and_boot_offset - Read persistent clock, and also offset
+ * from the boot.
+ *
+ * Weak dummy function for arches that do not yet support it.
+ * wall_time - current time as returned by persistent clock
+ * boot_offset - offset that is defined as wall_time - boot_time
+ * The default function calculates offset based on the current value of
+ * local_clock(). This way architectures that support sched_clock() but don't
+ * support dedicated boot time clock will provide the best estimate of the
+ * boot time.
+ */
+void __weak __init
+read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,
+ struct timespec64 *boot_offset)
+{
+ read_persistent_clock64(wall_time);
+ *boot_offset = ns_to_timespec64(local_clock());
+}
+
+/*
+ * Flag reflecting whether timekeeping_resume() has injected sleeptime.
+ *
+ * The flag starts of false and is only set when a suspend reaches
+ * timekeeping_suspend(), timekeeping_resume() sets it to false when the
+ * timekeeper clocksource is not stopping across suspend and has been
+ * used to update sleep time. If the timekeeper clocksource has stopped
+ * then the flag stays true and is used by the RTC resume code to decide
+ * whether sleeptime must be injected and if so the flag gets false then.
+ *
+ * If a suspend fails before reaching timekeeping_resume() then the flag
+ * stays false and prevents erroneous sleeptime injection.
+ */
+static bool suspend_timing_needed;
+
+/* 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 timespec64 wall_time, boot_offset, wall_to_mono;
+ struct timekeeper *tk = &tk_core.timekeeper;
+ struct clocksource *clock;
+ unsigned long flags;
+
+ read_persistent_wall_and_boot_offset(&wall_time, &boot_offset);
+ if (timespec64_valid_strict(&wall_time) &&
+ timespec64_to_ns(&wall_time) > 0) {
+ persistent_clock_exists = true;
+ } else if (timespec64_to_ns(&wall_time) != 0) {
+ pr_warn("Persistent clock returned invalid value");
+ wall_time = (struct timespec64){0};
+ }
+
+ if (timespec64_compare(&wall_time, &boot_offset) < 0)
+ boot_offset = (struct timespec64){0};
+
+ /*
+ * We want set wall_to_mono, so the following is true:
+ * wall time + wall_to_mono = boot time
+ */
+ wall_to_mono = timespec64_sub(boot_offset, wall_time);
+
+ 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, &wall_time);
+ tk->raw_sec = 0;
+
+ tk_set_wall_to_mono(tk, wall_to_mono);
+
+ timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
+
+ write_seqcount_end(&tk_core.seq);
+ raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+}
+
+/* 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,
+ const 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);
+}
+
+#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 !suspend_timing_needed;
+}
+
+/**
+ * 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;
+}
+
+/**
+ * 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(const 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);
+
+ suspend_timing_needed = false;
+
+ 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();
+}
+#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, nsec;
+ bool inject_sleeptime = 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);
+ nsec = clocksource_stop_suspend_timing(clock, cycle_now);
+ if (nsec > 0) {
+ ts_delta = ns_to_timespec64(nsec);
+ inject_sleeptime = true;
+ } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
+ ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
+ inject_sleeptime = true;
+ }
+
+ if (inject_sleeptime) {
+ suspend_timing_needed = false;
+ __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();
+}
+
+int timekeeping_suspend(void)
+{
+ struct timekeeper *tk = &tk_core.timekeeper;
+ unsigned long flags;
+ struct timespec64 delta, delta_delta;
+ static struct timespec64 old_delta;
+ struct clocksource *curr_clock;
+ u64 cycle_now;
+
+ 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;
+
+ suspend_timing_needed = true;
+
+ raw_spin_lock_irqsave(&timekeeper_lock, flags);
+ write_seqcount_begin(&tk_core.seq);
+ timekeeping_forward_now(tk);
+ timekeeping_suspended = 1;
+
+ /*
+ * Since we've called forward_now, cycle_last stores the value
+ * just read from the current clocksource. Save this to potentially
+ * use in suspend timing.
+ */
+ curr_clock = tk->tkr_mono.clock;
+ cycle_now = tk->tkr_mono.cycle_last;
+ clocksource_start_suspend_timing(curr_clock, cycle_now);
+
+ 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;
+}
+
+/* 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;
+}
+device_initcall(timekeeping_init_ops);
+
+/*
+ * Apply a multiplier adjustment to the timekeeper
+ */
+static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
+ s64 offset,
+ s32 mult_adj)
+{
+ s64 interval = tk->cycle_interval;
+
+ if (mult_adj == 0) {
+ return;
+ } else if (mult_adj == -1) {
+ interval = -interval;
+ offset = -offset;
+ } else if (mult_adj != 1) {
+ interval *= mult_adj;
+ offset *= mult_adj;
+ }
+
+ /*
+ * 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
+ */
+ 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;
+}
+
+/*
+ * 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)
+{
+ u32 mult;
+
+ /*
+ * Determine the multiplier from the current NTP tick length.
+ * Avoid expensive division when the tick length doesn't change.
+ */
+ if (likely(tk->ntp_tick == ntp_tick_length())) {
+ mult = tk->tkr_mono.mult - tk->ntp_err_mult;
+ } else {
+ tk->ntp_tick = ntp_tick_length();
+ mult = div64_u64((tk->ntp_tick >> tk->ntp_error_shift) -
+ tk->xtime_remainder, tk->cycle_interval);
+ }
+
+ /*
+ * If the clock is behind the NTP time, increase the multiplier by 1
+ * to catch up with it. If it's ahead and there was a remainder in the
+ * tick division, the clock will slow down. Otherwise it will stay
+ * ahead until the tick length changes to a non-divisible value.
+ */
+ tk->ntp_err_mult = tk->ntp_error > 0 ? 1 : 0;
+ mult += tk->ntp_err_mult;
+
+ timekeeping_apply_adjustment(tk, offset, mult - tk->tkr_mono.mult);
+
+ 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 have already accumulated the second and the NTP
+ * subsystem has been notified via second_overflow(), we need to skip
+ * the next update.
+ */
+ if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
+ tk->tkr_mono.xtime_nsec += (u64)NSEC_PER_SEC <<
+ tk->tkr_mono.shift;
+ tk->xtime_sec--;
+ tk->skip_second_overflow = 1;
+ }
+}
+
+/**
+ * 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++;
+
+ /*
+ * Skip NTP update if this second was accumulated before,
+ * i.e. xtime_nsec underflowed in timekeeping_adjust()
+ */
+ if (unlikely(tk->skip_second_overflow)) {
+ tk->skip_second_overflow = 0;
+ continue;
+ }
+
+ /* 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;
+}
+
+/**
+ * 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;
+}
+
+/*
+ * timekeeping_advance - Updates the timekeeper to the current time and
+ * current NTP tick length
+ */
+static void timekeeping_advance(enum timekeeping_adv_mode mode)
+{
+ 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;
+
+ if (mode != TK_ADV_TICK)
+ goto out;
+#else
+ offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
+ tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
+
+ /* Check if there's really nothing to do */
+ if (offset < real_tk->cycle_interval && mode == TK_ADV_TICK)
+ goto out;
+#endif
+
+ /* 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--;
+ }
+
+ /* Adjust the multiplier to correct NTP error */
+ 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();
+}
+
+/**
+ * update_wall_time - Uses the current clocksource to increment the wall time
+ *
+ */
+void update_wall_time(void)
+{
+ timekeeping_advance(TK_ADV_TICK);
+}
+
+/**
+ * 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);
+}
+EXPORT_SYMBOL_GPL(getboottime64);
+
+unsigned long get_seconds(void)
+{
+ struct timekeeper *tk = &tk_core.timekeeper;
+
+ return tk->xtime_sec;
+}
+EXPORT_SYMBOL(get_seconds);
+
+void ktime_get_coarse_real_ts64(struct timespec64 *ts)
+{
+ struct timekeeper *tk = &tk_core.timekeeper;
+ unsigned long seq;
+
+ do {
+ seq = read_seqcount_begin(&tk_core.seq);
+
+ *ts = tk_xtime(tk);
+ } while (read_seqcount_retry(&tk_core.seq, seq));
+}
+EXPORT_SYMBOL(ktime_get_coarse_real_ts64);
+
+void ktime_get_coarse_ts64(struct timespec64 *ts)
+{
+ 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(ts, now.tv_sec + mono.tv_sec,
+ now.tv_nsec + mono.tv_nsec);
+}
+EXPORT_SYMBOL(ktime_get_coarse_ts64);
+
+/*
+ * Must hold jiffies_lock
+ */
+void do_timer(unsigned long ticks)
+{
+ jiffies_64 += ticks;
+ calc_global_load(ticks);
+}
+
+/**
+ * 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;
+}
+
+/**
+ * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex
+ */
+static int timekeeping_validate_timex(const 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;
+}
+
+
+/**
+ * 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;
+ }
+
+ ktime_get_real_ts64(&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);
+
+ /* Update the multiplier immediately if frequency was set directly */
+ if (txc->modes & (ADJ_FREQUENCY | ADJ_TICK))
+ timekeeping_advance(TK_ADV_FREQ);
+
+ if (tai != orig_tai)
+ clock_was_set();
+
+ ntp_notify_cmos_timer();
+
+ return ret;
+}
+
+#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);
+}
+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();
+}