// SPDX-License-Identifier: GPL-2.0
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/*
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* Kernel timekeeping code and accessor functions. Based on code from
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* timer.c, moved in commit 8524070b7982.
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*/
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#include <linux/timekeeper_internal.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/percpu.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/nmi.h>
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#include <linux/sched.h>
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#include <linux/sched/loadavg.h>
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#include <linux/sched/clock.h>
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#include <linux/syscore_ops.h>
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#include <linux/clocksource.h>
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#include <linux/jiffies.h>
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#include <linux/time.h>
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#include <linux/timex.h>
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#include <linux/tick.h>
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#include <linux/stop_machine.h>
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#include <linux/pvclock_gtod.h>
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#include <linux/compiler.h>
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#include <linux/audit.h>
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#include <linux/random.h>
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#include "tick-internal.h"
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#include "ntp_internal.h"
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#include "timekeeping_internal.h"
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#define TK_CLEAR_NTP (1 << 0)
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#define TK_MIRROR (1 << 1)
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#define TK_CLOCK_WAS_SET (1 << 2)
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enum timekeeping_adv_mode {
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/* Update timekeeper when a tick has passed */
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TK_ADV_TICK,
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/* Update timekeeper on a direct frequency change */
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TK_ADV_FREQ
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};
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DEFINE_RAW_SPINLOCK(timekeeper_lock);
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/*
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* The most important data for readout fits into a single 64 byte
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* cache line.
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*/
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static struct {
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seqcount_raw_spinlock_t seq;
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struct timekeeper timekeeper;
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} tk_core ____cacheline_aligned = {
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.seq = SEQCNT_RAW_SPINLOCK_ZERO(tk_core.seq, &timekeeper_lock),
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};
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static struct timekeeper shadow_timekeeper;
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/* flag for if timekeeping is suspended */
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int __read_mostly timekeeping_suspended;
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/**
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* struct tk_fast - NMI safe timekeeper
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* @seq: Sequence counter for protecting updates. The lowest bit
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* is the index for the tk_read_base array
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* @base: tk_read_base array. Access is indexed by the lowest bit of
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* @seq.
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*
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* See @update_fast_timekeeper() below.
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*/
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struct tk_fast {
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seqcount_latch_t seq;
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struct tk_read_base base[2];
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};
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/* Suspend-time cycles value for halted fast timekeeper. */
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static u64 cycles_at_suspend;
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static u64 dummy_clock_read(struct clocksource *cs)
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{
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if (timekeeping_suspended)
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return cycles_at_suspend;
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return local_clock();
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}
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static struct clocksource dummy_clock = {
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.read = dummy_clock_read,
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};
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/*
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* Boot time initialization which allows local_clock() to be utilized
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* during early boot when clocksources are not available. local_clock()
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* returns nanoseconds already so no conversion is required, hence mult=1
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* and shift=0. When the first proper clocksource is installed then
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* the fast time keepers are updated with the correct values.
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*/
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#define FAST_TK_INIT \
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{ \
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.clock = &dummy_clock, \
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.mask = CLOCKSOURCE_MASK(64), \
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.mult = 1, \
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.shift = 0, \
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}
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static struct tk_fast tk_fast_mono ____cacheline_aligned = {
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.seq = SEQCNT_LATCH_ZERO(tk_fast_mono.seq),
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.base[0] = FAST_TK_INIT,
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.base[1] = FAST_TK_INIT,
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};
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static struct tk_fast tk_fast_raw ____cacheline_aligned = {
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.seq = SEQCNT_LATCH_ZERO(tk_fast_raw.seq),
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.base[0] = FAST_TK_INIT,
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.base[1] = FAST_TK_INIT,
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};
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static inline void tk_normalize_xtime(struct timekeeper *tk)
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{
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while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
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tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
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tk->xtime_sec++;
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}
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while (tk->tkr_raw.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_raw.shift)) {
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tk->tkr_raw.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
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tk->raw_sec++;
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}
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}
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static inline struct timespec64 tk_xtime(const struct timekeeper *tk)
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{
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struct timespec64 ts;
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ts.tv_sec = tk->xtime_sec;
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ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
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return ts;
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}
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static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
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{
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tk->xtime_sec = ts->tv_sec;
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tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
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}
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static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
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{
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tk->xtime_sec += ts->tv_sec;
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tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
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tk_normalize_xtime(tk);
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}
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static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
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{
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struct timespec64 tmp;
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/*
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* Verify consistency of: offset_real = -wall_to_monotonic
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* before modifying anything
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*/
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set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
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-tk->wall_to_monotonic.tv_nsec);
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WARN_ON_ONCE(tk->offs_real != timespec64_to_ktime(tmp));
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tk->wall_to_monotonic = wtm;
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set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
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tk->offs_real = timespec64_to_ktime(tmp);
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tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
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}
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static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
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{
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tk->offs_boot = ktime_add(tk->offs_boot, delta);
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/*
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* Timespec representation for VDSO update to avoid 64bit division
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* on every update.
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*/
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tk->monotonic_to_boot = ktime_to_timespec64(tk->offs_boot);
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}
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/*
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* tk_clock_read - atomic clocksource read() helper
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*
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* This helper is necessary to use in the read paths because, while the
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* seqcount ensures we don't return a bad value while structures are updated,
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* it doesn't protect from potential crashes. There is the possibility that
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* the tkr's clocksource may change between the read reference, and the
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* clock reference passed to the read function. This can cause crashes if
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* the wrong clocksource is passed to the wrong read function.
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* This isn't necessary to use when holding the timekeeper_lock or doing
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* a read of the fast-timekeeper tkrs (which is protected by its own locking
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* and update logic).
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*/
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static inline u64 tk_clock_read(const struct tk_read_base *tkr)
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{
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struct clocksource *clock = READ_ONCE(tkr->clock);
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return clock->read(clock);
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}
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#ifdef CONFIG_DEBUG_TIMEKEEPING
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#define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
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static void timekeeping_check_update(struct timekeeper *tk, u64 offset)
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{
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u64 max_cycles = tk->tkr_mono.clock->max_cycles;
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const char *name = tk->tkr_mono.clock->name;
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if (offset > max_cycles) {
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printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
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offset, name, max_cycles);
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printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
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} else {
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if (offset > (max_cycles >> 1)) {
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printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
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offset, name, max_cycles >> 1);
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printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
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}
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}
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if (tk->underflow_seen) {
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if (jiffies - tk->last_warning > WARNING_FREQ) {
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printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
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printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
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printk_deferred(" Your kernel is probably still fine.\n");
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tk->last_warning = jiffies;
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}
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tk->underflow_seen = 0;
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}
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if (tk->overflow_seen) {
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if (jiffies - tk->last_warning > WARNING_FREQ) {
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printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
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printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
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printk_deferred(" Your kernel is probably still fine.\n");
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tk->last_warning = jiffies;
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}
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tk->overflow_seen = 0;
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}
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}
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static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr)
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{
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struct timekeeper *tk = &tk_core.timekeeper;
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u64 now, last, mask, max, delta;
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unsigned int seq;
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/*
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* Since we're called holding a seqcount, the data may shift
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* under us while we're doing the calculation. This can cause
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* false positives, since we'd note a problem but throw the
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* results away. So nest another seqcount here to atomically
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* grab the points we are checking with.
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*/
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do {
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seq = read_seqcount_begin(&tk_core.seq);
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now = tk_clock_read(tkr);
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last = tkr->cycle_last;
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mask = tkr->mask;
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max = tkr->clock->max_cycles;
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} while (read_seqcount_retry(&tk_core.seq, seq));
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delta = clocksource_delta(now, last, mask);
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/*
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* Try to catch underflows by checking if we are seeing small
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* mask-relative negative values.
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*/
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if (unlikely((~delta & mask) < (mask >> 3))) {
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tk->underflow_seen = 1;
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delta = 0;
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}
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/* Cap delta value to the max_cycles values to avoid mult overflows */
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if (unlikely(delta > max)) {
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tk->overflow_seen = 1;
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delta = tkr->clock->max_cycles;
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}
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return delta;
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}
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#else
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static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset)
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{
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}
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static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr)
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{
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u64 cycle_now, delta;
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/* read clocksource */
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cycle_now = tk_clock_read(tkr);
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/* calculate the delta since the last update_wall_time */
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delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
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return delta;
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}
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#endif
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/**
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* tk_setup_internals - Set up internals to use clocksource clock.
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*
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* @tk: The target timekeeper to setup.
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* @clock: Pointer to clocksource.
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*
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* Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
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* pair and interval request.
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*
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* Unless you're the timekeeping code, you should not be using this!
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*/
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static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
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{
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u64 interval;
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u64 tmp, ntpinterval;
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struct clocksource *old_clock;
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++tk->cs_was_changed_seq;
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old_clock = tk->tkr_mono.clock;
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tk->tkr_mono.clock = clock;
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tk->tkr_mono.mask = clock->mask;
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tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);
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tk->tkr_raw.clock = clock;
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tk->tkr_raw.mask = clock->mask;
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tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
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/* Do the ns -> cycle conversion first, using original mult */
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tmp = NTP_INTERVAL_LENGTH;
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tmp <<= clock->shift;
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ntpinterval = tmp;
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tmp += clock->mult/2;
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do_div(tmp, clock->mult);
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if (tmp == 0)
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tmp = 1;
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interval = (u64) tmp;
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tk->cycle_interval = interval;
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/* Go back from cycles -> shifted ns */
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tk->xtime_interval = interval * clock->mult;
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tk->xtime_remainder = ntpinterval - tk->xtime_interval;
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tk->raw_interval = interval * clock->mult;
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/* if changing clocks, convert xtime_nsec shift units */
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if (old_clock) {
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int shift_change = clock->shift - old_clock->shift;
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if (shift_change < 0) {
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tk->tkr_mono.xtime_nsec >>= -shift_change;
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tk->tkr_raw.xtime_nsec >>= -shift_change;
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} else {
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tk->tkr_mono.xtime_nsec <<= shift_change;
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tk->tkr_raw.xtime_nsec <<= shift_change;
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}
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}
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tk->tkr_mono.shift = clock->shift;
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tk->tkr_raw.shift = clock->shift;
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tk->ntp_error = 0;
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tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
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tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
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/*
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* The timekeeper keeps its own mult values for the currently
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* active clocksource. These value will be adjusted via NTP
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* to counteract clock drifting.
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*/
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tk->tkr_mono.mult = clock->mult;
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tk->tkr_raw.mult = clock->mult;
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tk->ntp_err_mult = 0;
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tk->skip_second_overflow = 0;
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}
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/* Timekeeper helper functions. */
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#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
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static u32 default_arch_gettimeoffset(void) { return 0; }
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u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
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#else
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static inline u32 arch_gettimeoffset(void) { return 0; }
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#endif
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static inline u64 timekeeping_delta_to_ns(const struct tk_read_base *tkr, u64 delta)
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{
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u64 nsec;
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nsec = delta * tkr->mult + tkr->xtime_nsec;
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nsec >>= tkr->shift;
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/* If arch requires, add in get_arch_timeoffset() */
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return nsec + arch_gettimeoffset();
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}
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static inline u64 timekeeping_get_ns(const struct tk_read_base *tkr)
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{
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u64 delta;
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delta = timekeeping_get_delta(tkr);
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return timekeeping_delta_to_ns(tkr, delta);
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}
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static inline u64 timekeeping_cycles_to_ns(const struct tk_read_base *tkr, u64 cycles)
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{
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u64 delta;
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/* calculate the delta since the last update_wall_time */
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delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
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return timekeeping_delta_to_ns(tkr, delta);
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}
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/**
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* update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
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* @tkr: Timekeeping readout base from which we take the update
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*
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* We want to use this from any context including NMI and tracing /
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* instrumenting the timekeeping code itself.
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*
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* Employ the latch technique; see @raw_write_seqcount_latch.
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*
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* So if a NMI hits the update of base[0] then it will use base[1]
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* which is still consistent. In the worst case this can result is a
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* slightly wrong timestamp (a few nanoseconds). See
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* @ktime_get_mono_fast_ns.
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*/
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static void update_fast_timekeeper(const struct tk_read_base *tkr,
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struct tk_fast *tkf)
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{
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struct tk_read_base *base = tkf->base;
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/* Force readers off to base[1] */
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raw_write_seqcount_latch(&tkf->seq);
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/* Update base[0] */
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memcpy(base, tkr, sizeof(*base));
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/* Force readers back to base[0] */
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raw_write_seqcount_latch(&tkf->seq);
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/* Update base[1] */
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memcpy(base + 1, base, sizeof(*base));
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}
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/**
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* ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
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*
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* This timestamp is not guaranteed to be monotonic across an update.
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* The timestamp is calculated by:
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*
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* now = base_mono + clock_delta * slope
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*
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* So if the update lowers the slope, readers who are forced to the
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* not yet updated second array are still using the old steeper slope.
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*
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* tmono
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* ^
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* | o n
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* | o n
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* | u
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* | o
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* |o
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* |12345678---> reader order
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*
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* o = old slope
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* u = update
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* n = new slope
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*
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* So reader 6 will observe time going backwards versus reader 5.
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*
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* While other CPUs are likely to be able observe that, the only way
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* for a CPU local observation is when an NMI hits in the middle of
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* the update. Timestamps taken from that NMI context might be ahead
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* of the following timestamps. Callers need to be aware of that and
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* deal with it.
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*/
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static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
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{
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struct tk_read_base *tkr;
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unsigned int seq;
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u64 now;
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do {
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seq = raw_read_seqcount_latch(&tkf->seq);
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tkr = tkf->base + (seq & 0x01);
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now = ktime_to_ns(tkr->base);
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now += timekeeping_delta_to_ns(tkr,
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clocksource_delta(
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tk_clock_read(tkr),
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tkr->cycle_last,
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tkr->mask));
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} while (read_seqcount_latch_retry(&tkf->seq, seq));
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return now;
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}
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u64 ktime_get_mono_fast_ns(void)
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{
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return __ktime_get_fast_ns(&tk_fast_mono);
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}
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EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
|
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u64 ktime_get_raw_fast_ns(void)
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{
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return __ktime_get_fast_ns(&tk_fast_raw);
|
}
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EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
|
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/**
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* 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 seqcounts. 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
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* timekeeping_inject_sleeptime64()
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* __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(struct tk_fast *tkf, u64 *mono)
|
{
|
struct tk_read_base *tkr;
|
u64 basem, baser, delta;
|
unsigned int seq;
|
|
do {
|
seq = raw_read_seqcount_latch(&tkf->seq);
|
tkr = tkf->base + (seq & 0x01);
|
basem = ktime_to_ns(tkr->base);
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baser = ktime_to_ns(tkr->base_real);
|
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delta = timekeeping_delta_to_ns(tkr,
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clocksource_delta(tk_clock_read(tkr),
|
tkr->cycle_last, tkr->mask));
|
} while (read_seqcount_latch_retry(&tkf->seq, seq));
|
|
if (mono)
|
*mono = basem + delta;
|
return baser + delta;
|
}
|
|
/**
|
* 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(&tk_fast_mono, NULL);
|
}
|
EXPORT_SYMBOL_GPL(ktime_get_real_fast_ns);
|
|
/**
|
* ktime_get_fast_timestamps: - NMI safe timestamps
|
* @snapshot: Pointer to timestamp storage
|
*
|
* Stores clock monotonic, boottime and realtime timestamps.
|
*
|
* Boot time is a racy access on 32bit systems if the sleep time injection
|
* happens late during resume and not in timekeeping_resume(). That could
|
* be avoided by expanding struct tk_read_base with boot offset for 32bit
|
* and adding more overhead to the update. As this is a hard to observe
|
* once per resume event which can be filtered with reasonable effort using
|
* the accurate mono/real timestamps, it's probably not worth the trouble.
|
*
|
* Aside of that it might be possible on 32 and 64 bit to observe the
|
* following when the sleep time injection happens late:
|
*
|
* CPU 0 CPU 1
|
* timekeeping_resume()
|
* ktime_get_fast_timestamps()
|
* mono, real = __ktime_get_real_fast()
|
* inject_sleep_time()
|
* update boot offset
|
* boot = mono + bootoffset;
|
*
|
* That means that boot time already has the sleep time adjustment, but
|
* real time does not. On the next readout both are in sync again.
|
*
|
* Preventing this for 64bit is not really feasible without destroying the
|
* careful cache layout of the timekeeper because the sequence count and
|
* struct tk_read_base would then need two cache lines instead of one.
|
*
|
* Access to the time keeper clock source is disabled accross the innermost
|
* steps of suspend/resume. The accessors still work, but the timestamps
|
* are frozen until time keeping is resumed which happens very early.
|
*
|
* For regular suspend/resume there is no observable difference vs. sched
|
* clock, but it might affect some of the nasty low level debug printks.
|
*
|
* OTOH, access to sched clock is not guaranteed accross suspend/resume on
|
* all systems either so it depends on the hardware in use.
|
*
|
* If that turns out to be a real problem then this could be mitigated by
|
* using sched clock in a similar way as during early boot. But it's not as
|
* trivial as on early boot because it needs some careful protection
|
* against the clock monotonic timestamp jumping backwards on resume.
|
*/
|
void ktime_get_fast_timestamps(struct ktime_timestamps *snapshot)
|
{
|
struct timekeeper *tk = &tk_core.timekeeper;
|
|
snapshot->real = __ktime_get_real_fast(&tk_fast_mono, &snapshot->mono);
|
snapshot->boot = snapshot->mono + ktime_to_ns(data_race(tk->offs_boot));
|
}
|
|
/**
|
* 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 int 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];
|
u64 nsecs;
|
|
WARN_ON(timekeeping_suspended);
|
|
do {
|
seq = read_seqcount_begin(&tk_core.seq);
|
base = ktime_add(tk->tkr_mono.base, *offset);
|
nsecs = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
|
|
} while (read_seqcount_retry(&tk_core.seq, seq));
|
|
return ktime_add_ns(base, nsecs);
|
}
|
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 int 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.
|
*/
|
noinstr 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 int 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 = div64_u64(rem * mult, 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 int 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_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_settod(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 = timespec64_sub(*ts, xt);
|
|
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();
|
|
if (!ret) {
|
audit_tk_injoffset(ts_delta);
|
add_device_randomness(ts, sizeof(*ts));
|
}
|
|
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_settod(&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 int 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 int 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 int 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_clock64 - 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_clock64(struct timespec64 *ts)
|
{
|
ts->tv_sec = 0;
|
ts->tv_nsec = 0;
|
}
|
|
/**
|
* 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_settod(&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
|
* 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);
|
|
void ktime_get_coarse_real_ts64(struct timespec64 *ts)
|
{
|
struct timekeeper *tk = &tk_core.timekeeper;
|
unsigned int 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 int 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();
|
}
|
|
/**
|
* 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 __kernel_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;
|
}
|
|
/**
|
* random_get_entropy_fallback - Returns the raw clock source value,
|
* used by random.c for platforms with no valid random_get_entropy().
|
*/
|
unsigned long random_get_entropy_fallback(void)
|
{
|
struct tk_read_base *tkr = &tk_core.timekeeper.tkr_mono;
|
struct clocksource *clock = READ_ONCE(tkr->clock);
|
|
if (unlikely(timekeeping_suspended || !clock))
|
return 0;
|
return clock->read(clock);
|
}
|
EXPORT_SYMBOL_GPL(random_get_entropy_fallback);
|
|
/**
|
* do_adjtimex() - Accessor function to NTP __do_adjtimex function
|
*/
|
int do_adjtimex(struct __kernel_timex *txc)
|
{
|
struct timekeeper *tk = &tk_core.timekeeper;
|
struct audit_ntp_data ad;
|
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;
|
add_device_randomness(txc, sizeof(*txc));
|
|
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;
|
|
audit_tk_injoffset(delta);
|
}
|
|
audit_ntp_init(&ad);
|
|
ktime_get_real_ts64(&ts);
|
add_device_randomness(&ts, sizeof(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, &ad);
|
|
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);
|
|
audit_ntp_log(&ad);
|
|
/* 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)
|
{
|
raw_spin_lock(&jiffies_lock);
|
write_seqcount_begin(&jiffies_seq);
|
do_timer(ticks);
|
write_seqcount_end(&jiffies_seq);
|
raw_spin_unlock(&jiffies_lock);
|
update_wall_time();
|
}
|
