diff options
Diffstat (limited to 'kernel/time/timekeeping.c')
| -rw-r--r-- | kernel/time/timekeeping.c | 3300 |
1 files changed, 2337 insertions, 963 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 48b9fffabdc2..3ec3daa4acab 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1,97 +1,304 @@ +// SPDX-License-Identifier: GPL-2.0 /* - * linux/kernel/time/timekeeping.c - * - * Kernel timekeeping code and accessor functions - * - * This code was moved from linux/kernel/timer.c. - * Please see that file for copyright and history logs. - * + * Kernel timekeeping code and accessor functions. Based on code from + * timer.c, moved in commit 8524070b7982. */ - #include <linux/timekeeper_internal.h> #include <linux/module.h> #include <linux/interrupt.h> +#include <linux/kobject.h> #include <linux/percpu.h> #include <linux/init.h> #include <linux/mm.h> +#include <linux/nmi.h> #include <linux/sched.h> +#include <linux/sched/loadavg.h> +#include <linux/sched/clock.h> #include <linux/syscore_ops.h> #include <linux/clocksource.h> #include <linux/jiffies.h> #include <linux/time.h> +#include <linux/timex.h> #include <linux/tick.h> #include <linux/stop_machine.h> #include <linux/pvclock_gtod.h> +#include <linux/compiler.h> +#include <linux/audit.h> +#include <linux/random.h> + +#include <vdso/auxclock.h> #include "tick-internal.h" #include "ntp_internal.h" #include "timekeeping_internal.h" #define TK_CLEAR_NTP (1 << 0) -#define TK_MIRROR (1 << 1) -#define TK_CLOCK_WAS_SET (1 << 2) +#define TK_CLOCK_WAS_SET (1 << 1) + +#define TK_UPDATE_ALL (TK_CLEAR_NTP | TK_CLOCK_WAS_SET) -static struct timekeeper timekeeper; -static DEFINE_RAW_SPINLOCK(timekeeper_lock); -static seqcount_t timekeeper_seq; -static struct timekeeper shadow_timekeeper; +enum timekeeping_adv_mode { + /* Update timekeeper when a tick has passed */ + TK_ADV_TICK, + + /* Update timekeeper on a direct frequency change */ + TK_ADV_FREQ +}; + +/* + * The most important data for readout fits into a single 64 byte + * cache line. + */ +struct tk_data { + seqcount_raw_spinlock_t seq; + struct timekeeper timekeeper; + struct timekeeper shadow_timekeeper; + raw_spinlock_t lock; +} ____cacheline_aligned; + +static struct tk_data timekeeper_data[TIMEKEEPERS_MAX]; + +/* The core timekeeper */ +#define tk_core (timekeeper_data[TIMEKEEPER_CORE]) + +#ifdef CONFIG_POSIX_AUX_CLOCKS +static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts) +{ + return ktime_get_aux_ts64(CLOCK_AUX + tkid - TIMEKEEPER_AUX_FIRST, ts); +} + +static inline bool tk_is_aux(const struct timekeeper *tk) +{ + return tk->id >= TIMEKEEPER_AUX_FIRST && tk->id <= TIMEKEEPER_AUX_LAST; +} +#else +static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts) +{ + return false; +} + +static inline bool tk_is_aux(const struct timekeeper *tk) +{ + return false; +} +#endif + +static inline void tk_update_aux_offs(struct timekeeper *tk, ktime_t offs) +{ + tk->offs_aux = offs; + tk->monotonic_to_aux = ktime_to_timespec64(offs); +} /* flag for if timekeeping is suspended */ int __read_mostly timekeeping_suspended; -/* Flag for if there is a persistent clock on this platform */ -bool __read_mostly persistent_clock_exist = false; +/** + * struct tk_fast - NMI safe timekeeper + * @seq: Sequence counter for protecting updates. The lowest bit + * is the index for the tk_read_base array + * @base: tk_read_base array. Access is indexed by the lowest bit of + * @seq. + * + * See @update_fast_timekeeper() below. + */ +struct tk_fast { + seqcount_latch_t seq; + struct tk_read_base base[2]; +}; + +/* Suspend-time cycles value for halted fast timekeeper. */ +static u64 cycles_at_suspend; + +static u64 dummy_clock_read(struct clocksource *cs) +{ + if (timekeeping_suspended) + return cycles_at_suspend; + return local_clock(); +} + +static struct clocksource dummy_clock = { + .read = dummy_clock_read, +}; + +/* + * Boot time initialization which allows local_clock() to be utilized + * during early boot when clocksources are not available. local_clock() + * returns nanoseconds already so no conversion is required, hence mult=1 + * and shift=0. When the first proper clocksource is installed then + * the fast time keepers are updated with the correct values. + */ +#define FAST_TK_INIT \ + { \ + .clock = &dummy_clock, \ + .mask = CLOCKSOURCE_MASK(64), \ + .mult = 1, \ + .shift = 0, \ + } + +static struct tk_fast tk_fast_mono ____cacheline_aligned = { + .seq = SEQCNT_LATCH_ZERO(tk_fast_mono.seq), + .base[0] = FAST_TK_INIT, + .base[1] = FAST_TK_INIT, +}; + +static struct tk_fast tk_fast_raw ____cacheline_aligned = { + .seq = SEQCNT_LATCH_ZERO(tk_fast_raw.seq), + .base[0] = FAST_TK_INIT, + .base[1] = FAST_TK_INIT, +}; + +#ifdef CONFIG_POSIX_AUX_CLOCKS +static __init void tk_aux_setup(void); +static void tk_aux_update_clocksource(void); +static void tk_aux_advance(void); +#else +static inline void tk_aux_setup(void) { } +static inline void tk_aux_update_clocksource(void) { } +static inline void tk_aux_advance(void) { } +#endif + +unsigned long timekeeper_lock_irqsave(void) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&tk_core.lock, flags); + return flags; +} + +void timekeeper_unlock_irqrestore(unsigned long flags) +{ + raw_spin_unlock_irqrestore(&tk_core.lock, flags); +} + +/* + * Multigrain timestamps require tracking the latest fine-grained timestamp + * that has been issued, and never returning a coarse-grained timestamp that is + * earlier than that value. + * + * mg_floor represents the latest fine-grained time that has been handed out as + * a file timestamp on the system. This is tracked as a monotonic ktime_t, and + * converted to a realtime clock value on an as-needed basis. + * + * Maintaining mg_floor ensures the multigrain interfaces never issue a + * timestamp earlier than one that has been previously issued. + * + * The exception to this rule is when there is a backward realtime clock jump. If + * such an event occurs, a timestamp can appear to be earlier than a previous one. + */ +static __cacheline_aligned_in_smp atomic64_t mg_floor; static inline void tk_normalize_xtime(struct timekeeper *tk) { - while (tk->xtime_nsec >= ((u64)NSEC_PER_SEC << tk->shift)) { - tk->xtime_nsec -= (u64)NSEC_PER_SEC << tk->shift; + while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) { + tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift; tk->xtime_sec++; } + while (tk->tkr_raw.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_raw.shift)) { + tk->tkr_raw.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_raw.shift; + tk->raw_sec++; + } } -static void tk_set_xtime(struct timekeeper *tk, const struct timespec *ts) +static inline struct timespec64 tk_xtime(const struct timekeeper *tk) +{ + struct timespec64 ts; + + ts.tv_sec = tk->xtime_sec; + ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift); + return ts; +} + +static inline struct timespec64 tk_xtime_coarse(const struct timekeeper *tk) +{ + struct timespec64 ts; + + ts.tv_sec = tk->xtime_sec; + ts.tv_nsec = tk->coarse_nsec; + return ts; +} + +/* + * Update the nanoseconds part for the coarse time keepers. They can't rely + * on xtime_nsec because xtime_nsec could be adjusted by a small negative + * amount when the multiplication factor of the clock is adjusted, which + * could cause the coarse clocks to go slightly backwards. See + * timekeeping_apply_adjustment(). Thus we keep a separate copy for the coarse + * clockids which only is updated when the clock has been set or we have + * accumulated time. + */ +static inline void tk_update_coarse_nsecs(struct timekeeper *tk) +{ + tk->coarse_nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift; +} + +static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts) { tk->xtime_sec = ts->tv_sec; - tk->xtime_nsec = (u64)ts->tv_nsec << tk->shift; + tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift; + tk_update_coarse_nsecs(tk); } -static void tk_xtime_add(struct timekeeper *tk, const struct timespec *ts) +static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts) { tk->xtime_sec += ts->tv_sec; - tk->xtime_nsec += (u64)ts->tv_nsec << tk->shift; + tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift; tk_normalize_xtime(tk); + tk_update_coarse_nsecs(tk); } -static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec wtm) +static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm) { - struct timespec tmp; + struct timespec64 tmp; /* * Verify consistency of: offset_real = -wall_to_monotonic * before modifying anything */ - set_normalized_timespec(&tmp, -tk->wall_to_monotonic.tv_sec, + set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec, -tk->wall_to_monotonic.tv_nsec); - WARN_ON_ONCE(tk->offs_real.tv64 != timespec_to_ktime(tmp).tv64); + WARN_ON_ONCE(tk->offs_real != timespec64_to_ktime(tmp)); tk->wall_to_monotonic = wtm; - set_normalized_timespec(&tmp, -wtm.tv_sec, -wtm.tv_nsec); - tk->offs_real = timespec_to_ktime(tmp); - tk->offs_tai = ktime_sub(tk->offs_real, ktime_set(tk->tai_offset, 0)); + set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec); + /* Paired with READ_ONCE() in ktime_mono_to_any() */ + WRITE_ONCE(tk->offs_real, timespec64_to_ktime(tmp)); + WRITE_ONCE(tk->offs_tai, ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0))); +} + +static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta) +{ + /* Paired with READ_ONCE() in ktime_mono_to_any() */ + WRITE_ONCE(tk->offs_boot, ktime_add(tk->offs_boot, delta)); + /* + * Timespec representation for VDSO update to avoid 64bit division + * on every update. + */ + tk->monotonic_to_boot = ktime_to_timespec64(tk->offs_boot); } -static void tk_set_sleep_time(struct timekeeper *tk, struct timespec t) +/* + * tk_clock_read - atomic clocksource read() helper + * + * This helper is necessary to use in the read paths because, while the + * seqcount ensures we don't return a bad value while structures are updated, + * it doesn't protect from potential crashes. There is the possibility that + * the tkr's clocksource may change between the read reference, and the + * clock reference passed to the read function. This can cause crashes if + * the wrong clocksource is passed to the wrong read function. + * This isn't necessary to use when holding the tk_core.lock or doing + * a read of the fast-timekeeper tkrs (which is protected by its own locking + * and update logic). + */ +static inline u64 tk_clock_read(const struct tk_read_base *tkr) { - /* Verify consistency before modifying */ - WARN_ON_ONCE(tk->offs_boot.tv64 != timespec_to_ktime(tk->total_sleep_time).tv64); + struct clocksource *clock = READ_ONCE(tkr->clock); - tk->total_sleep_time = t; - tk->offs_boot = timespec_to_ktime(t); + return clock->read(clock); } /** - * timekeeper_setup_internals - Set up internals to use clocksource clock. + * tk_setup_internals - Set up internals to use clocksource clock. * + * @tk: The target timekeeper to setup. * @clock: Pointer to clocksource. * * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment @@ -101,13 +308,19 @@ static void tk_set_sleep_time(struct timekeeper *tk, struct timespec t) */ static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock) { - cycle_t interval; + u64 interval; u64 tmp, ntpinterval; struct clocksource *old_clock; - old_clock = tk->clock; - tk->clock = clock; - tk->cycle_last = clock->cycle_last = clock->read(clock); + ++tk->cs_was_changed_seq; + old_clock = tk->tkr_mono.clock; + tk->tkr_mono.clock = clock; + tk->tkr_mono.mask = clock->mask; + tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono); + + tk->tkr_raw.clock = clock; + tk->tkr_raw.mask = clock->mask; + tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last; /* Do the ns -> cycle conversion first, using original mult */ tmp = NTP_INTERVAL_LENGTH; @@ -118,89 +331,277 @@ static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock) if (tmp == 0) tmp = 1; - interval = (cycle_t) tmp; + interval = (u64) tmp; tk->cycle_interval = interval; /* Go back from cycles -> shifted ns */ - tk->xtime_interval = (u64) interval * clock->mult; + tk->xtime_interval = interval * clock->mult; tk->xtime_remainder = ntpinterval - tk->xtime_interval; - tk->raw_interval = - ((u64) interval * clock->mult) >> clock->shift; + tk->raw_interval = interval * clock->mult; /* if changing clocks, convert xtime_nsec shift units */ if (old_clock) { int shift_change = clock->shift - old_clock->shift; - if (shift_change < 0) - tk->xtime_nsec >>= -shift_change; - else - tk->xtime_nsec <<= shift_change; + if (shift_change < 0) { + tk->tkr_mono.xtime_nsec >>= -shift_change; + tk->tkr_raw.xtime_nsec >>= -shift_change; + } else { + tk->tkr_mono.xtime_nsec <<= shift_change; + tk->tkr_raw.xtime_nsec <<= shift_change; + } } - tk->shift = clock->shift; + + tk->tkr_mono.shift = clock->shift; + tk->tkr_raw.shift = clock->shift; tk->ntp_error = 0; tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; + tk->ntp_tick = ntpinterval << tk->ntp_error_shift; /* * The timekeeper keeps its own mult values for the currently * active clocksource. These value will be adjusted via NTP * to counteract clock drifting. */ - tk->mult = clock->mult; + tk->tkr_mono.mult = clock->mult; + tk->tkr_raw.mult = clock->mult; + tk->ntp_err_mult = 0; + tk->skip_second_overflow = 0; } /* Timekeeper helper functions. */ +static noinline u64 delta_to_ns_safe(const struct tk_read_base *tkr, u64 delta) +{ + return mul_u64_u32_add_u64_shr(delta, tkr->mult, tkr->xtime_nsec, tkr->shift); +} + +static inline u64 timekeeping_cycles_to_ns(const struct tk_read_base *tkr, u64 cycles) +{ + /* Calculate the delta since the last update_wall_time() */ + u64 mask = tkr->mask, delta = (cycles - tkr->cycle_last) & mask; + + /* + * This detects both negative motion and the case where the delta + * overflows the multiplication with tkr->mult. + */ + if (unlikely(delta > tkr->clock->max_cycles)) { + /* + * Handle clocksource inconsistency between CPUs to prevent + * time from going backwards by checking for the MSB of the + * mask being set in the delta. + */ + if (delta & ~(mask >> 1)) + return tkr->xtime_nsec >> tkr->shift; + + return delta_to_ns_safe(tkr, delta); + } -#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET -u32 (*arch_gettimeoffset)(void); + return ((delta * tkr->mult) + tkr->xtime_nsec) >> tkr->shift; +} -u32 get_arch_timeoffset(void) +static __always_inline u64 timekeeping_get_ns(const struct tk_read_base *tkr) { - if (likely(arch_gettimeoffset)) - return arch_gettimeoffset(); - return 0; + return timekeeping_cycles_to_ns(tkr, tk_clock_read(tkr)); } -#else -static inline u32 get_arch_timeoffset(void) { return 0; } -#endif -static inline s64 timekeeping_get_ns(struct timekeeper *tk) +/** + * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper. + * @tkr: Timekeeping readout base from which we take the update + * @tkf: Pointer to NMI safe timekeeper + * + * We want to use this from any context including NMI and tracing / + * instrumenting the timekeeping code itself. + * + * Employ the latch technique; see @write_seqcount_latch. + * + * So if a NMI hits the update of base[0] then it will use base[1] + * which is still consistent. In the worst case this can result is a + * slightly wrong timestamp (a few nanoseconds). See + * @ktime_get_mono_fast_ns. + */ +static void update_fast_timekeeper(const struct tk_read_base *tkr, + struct tk_fast *tkf) { - cycle_t cycle_now, cycle_delta; - struct clocksource *clock; - s64 nsec; + struct tk_read_base *base = tkf->base; - /* read clocksource: */ - clock = tk->clock; - cycle_now = clock->read(clock); + /* Force readers off to base[1] */ + write_seqcount_latch_begin(&tkf->seq); - /* calculate the delta since the last update_wall_time: */ - cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; + /* Update base[0] */ + memcpy(base, tkr, sizeof(*base)); - nsec = cycle_delta * tk->mult + tk->xtime_nsec; - nsec >>= tk->shift; + /* Force readers back to base[0] */ + write_seqcount_latch(&tkf->seq); - /* If arch requires, add in get_arch_timeoffset() */ - return nsec + get_arch_timeoffset(); + /* Update base[1] */ + memcpy(base + 1, base, sizeof(*base)); + + write_seqcount_latch_end(&tkf->seq); } -static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk) +static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf) { - cycle_t cycle_now, cycle_delta; - struct clocksource *clock; - s64 nsec; + struct tk_read_base *tkr; + unsigned int seq; + u64 now; - /* read clocksource: */ - clock = tk->clock; - cycle_now = clock->read(clock); + do { + seq = read_seqcount_latch(&tkf->seq); + tkr = tkf->base + (seq & 0x01); + now = ktime_to_ns(tkr->base); + now += timekeeping_get_ns(tkr); + } while (read_seqcount_latch_retry(&tkf->seq, seq)); - /* calculate the delta since the last update_wall_time: */ - cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; + return now; +} - /* convert delta to nanoseconds. */ - nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); +/** + * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic + * + * This timestamp is not guaranteed to be monotonic across an update. + * The timestamp is calculated by: + * + * now = base_mono + clock_delta * slope + * + * So if the update lowers the slope, readers who are forced to the + * not yet updated second array are still using the old steeper slope. + * + * tmono + * ^ + * | o n + * | o n + * | u + * | o + * |o + * |12345678---> reader order + * + * o = old slope + * u = update + * n = new slope + * + * So reader 6 will observe time going backwards versus reader 5. + * + * While other CPUs are likely to be able to observe that, the only way + * for a CPU local observation is when an NMI hits in the middle of + * the update. Timestamps taken from that NMI context might be ahead + * of the following timestamps. Callers need to be aware of that and + * deal with it. + */ +u64 notrace ktime_get_mono_fast_ns(void) +{ + return __ktime_get_fast_ns(&tk_fast_mono); +} +EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns); - /* If arch requires, add in get_arch_timeoffset() */ - return nsec + get_arch_timeoffset(); +/** + * ktime_get_raw_fast_ns - Fast NMI safe access to clock monotonic raw + * + * Contrary to ktime_get_mono_fast_ns() this is always correct because the + * conversion factor is not affected by NTP/PTP correction. + */ +u64 notrace ktime_get_raw_fast_ns(void) +{ + return __ktime_get_fast_ns(&tk_fast_raw); +} +EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns); + +/** + * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock. + * + * To keep it NMI safe since we're accessing from tracing, we're not using a + * separate timekeeper with updates to monotonic clock and boot offset + * protected with 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 + * timekeeping_inject_sleeptime64() + * __timekeeping_inject_sleeptime(tk, delta); + * timestamp(); + * timekeeping_update_staged(tkd, 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. + * + * The caveats vs. timestamp ordering as documented for ktime_get_mono_fast_ns() + * apply as well. + */ +u64 notrace ktime_get_boot_fast_ns(void) +{ + struct timekeeper *tk = &tk_core.timekeeper; + + return (ktime_get_mono_fast_ns() + ktime_to_ns(data_race(tk->offs_boot))); +} +EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns); + +/** + * ktime_get_tai_fast_ns - NMI safe and fast access to tai clock. + * + * The same limitations as described for ktime_get_boot_fast_ns() apply. The + * mono time and the TAI offset are not read atomically which may yield wrong + * readouts. However, an update of the TAI offset is an rare event e.g., caused + * by settime or adjtimex with an offset. The user of this function has to deal + * with the possibility of wrong timestamps in post processing. + */ +u64 notrace ktime_get_tai_fast_ns(void) +{ + struct timekeeper *tk = &tk_core.timekeeper; + + return (ktime_get_mono_fast_ns() + ktime_to_ns(data_race(tk->offs_tai))); +} +EXPORT_SYMBOL_GPL(ktime_get_tai_fast_ns); + +/** + * ktime_get_real_fast_ns: - NMI safe and fast access to clock realtime. + * + * See ktime_get_mono_fast_ns() for documentation of the time stamp ordering. + */ +u64 ktime_get_real_fast_ns(void) +{ + struct tk_fast *tkf = &tk_fast_mono; + struct tk_read_base *tkr; + u64 baser, delta; + unsigned int seq; + + do { + seq = raw_read_seqcount_latch(&tkf->seq); + tkr = tkf->base + (seq & 0x01); + baser = ktime_to_ns(tkr->base_real); + delta = timekeeping_get_ns(tkr); + } while (raw_read_seqcount_latch_retry(&tkf->seq, seq)); + + return baser + delta; +} +EXPORT_SYMBOL_GPL(ktime_get_real_fast_ns); + +/** + * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource. + * @tk: Timekeeper to snapshot. + * + * It generally is unsafe to access the clocksource after timekeeping has been + * suspended, so take a snapshot of the readout base of @tk and use it as the + * fast timekeeper's readout base while suspended. It will return the same + * number of cycles every time until timekeeping is resumed at which time the + * proper readout base for the fast timekeeper will be restored automatically. + */ +static void halt_fast_timekeeper(const struct timekeeper *tk) +{ + static struct tk_read_base tkr_dummy; + const struct tk_read_base *tkr = &tk->tkr_mono; + + memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy)); + cycles_at_suspend = tk_clock_read(tkr); + tkr_dummy.clock = &dummy_clock; + tkr_dummy.base_real = tkr->base + tk->offs_real; + update_fast_timekeeper(&tkr_dummy, &tk_fast_mono); + + tkr = &tk->tkr_raw; + memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy)); + tkr_dummy.clock = &dummy_clock; + update_fast_timekeeper(&tkr_dummy, &tk_fast_raw); } static RAW_NOTIFIER_HEAD(pvclock_gtod_chain); @@ -212,17 +613,16 @@ static void update_pvclock_gtod(struct timekeeper *tk, bool was_set) /** * pvclock_gtod_register_notifier - register a pvclock timedata update listener + * @nb: Pointer to the notifier block to register */ int pvclock_gtod_register_notifier(struct notifier_block *nb) { - struct timekeeper *tk = &timekeeper; - unsigned long flags; + struct timekeeper *tk = &tk_core.timekeeper; int ret; - raw_spin_lock_irqsave(&timekeeper_lock, flags); + guard(raw_spinlock_irqsave)(&tk_core.lock); ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb); update_pvclock_gtod(tk, true); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); return ret; } @@ -231,36 +631,132 @@ EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier); /** * pvclock_gtod_unregister_notifier - unregister a pvclock * timedata update listener + * @nb: Pointer to the notifier block to unregister */ int pvclock_gtod_unregister_notifier(struct notifier_block *nb) { - unsigned long flags; - int ret; + guard(raw_spinlock_irqsave)(&tk_core.lock); + return raw_notifier_chain_unregister(&pvclock_gtod_chain, nb); +} +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(tk->id); + if (tk->next_leap_ktime != KTIME_MAX) + /* Convert to monotonic time */ + tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real); +} - raw_spin_lock_irqsave(&timekeeper_lock, flags); - ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); +/* + * Leap state update for both shadow and the real timekeeper + * Separate to spare a full memcpy() of the timekeeper. + */ +static void tk_update_leap_state_all(struct tk_data *tkd) +{ + write_seqcount_begin(&tkd->seq); + tk_update_leap_state(&tkd->shadow_timekeeper); + tkd->timekeeper.next_leap_ktime = tkd->shadow_timekeeper.next_leap_ktime; + write_seqcount_end(&tkd->seq); +} - return ret; +/* + * 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); +} + +/* + * Restore the shadow timekeeper from the real timekeeper. + */ +static void timekeeping_restore_shadow(struct tk_data *tkd) +{ + lockdep_assert_held(&tkd->lock); + memcpy(&tkd->shadow_timekeeper, &tkd->timekeeper, sizeof(tkd->timekeeper)); } -EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier); -/* must hold timekeeper_lock */ -static void timekeeping_update(struct timekeeper *tk, unsigned int action) +static void timekeeping_update_from_shadow(struct tk_data *tkd, unsigned int action) { + struct timekeeper *tk = &tkd->shadow_timekeeper; + + lockdep_assert_held(&tkd->lock); + + /* + * Block out readers before running the updates below because that + * updates VDSO and other time related infrastructure. Not blocking + * the readers might let a reader see time going backwards when + * reading from the VDSO after the VDSO update and then reading in + * the kernel from the timekeeper before that got updated. + */ + write_seqcount_begin(&tkd->seq); + if (action & TK_CLEAR_NTP) { tk->ntp_error = 0; - ntp_clear(); + ntp_clear(tk->id); } - update_vsyscall(tk); - update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET); - if (action & TK_MIRROR) - memcpy(&shadow_timekeeper, &timekeeper, sizeof(timekeeper)); + tk_update_leap_state(tk); + tk_update_ktime_data(tk); + tk->tkr_mono.base_real = tk->tkr_mono.base + tk->offs_real; + + if (tk->id == TIMEKEEPER_CORE) { + update_vsyscall(tk); + update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET); + + update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono); + update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw); + } else if (tk_is_aux(tk)) { + vdso_time_update_aux(tk); + } + + if (action & TK_CLOCK_WAS_SET) + tk->clock_was_set_seq++; + + /* + * Update the real timekeeper. + * + * We could avoid this memcpy() by switching pointers, but that has + * the downside that the reader side does not longer benefit from + * the cacheline optimized data layout of the timekeeper and requires + * another indirection. + */ + memcpy(&tkd->timekeeper, tk, sizeof(*tk)); + write_seqcount_end(&tkd->seq); } /** * timekeeping_forward_now - update clock to the current time + * @tk: Pointer to the timekeeper to update * * Forward the current clock to update its state since the last call to * update_wall_time(). This is useful before significant clock changes, @@ -268,389 +764,856 @@ static void timekeeping_update(struct timekeeper *tk, unsigned int action) */ static void timekeeping_forward_now(struct timekeeper *tk) { - cycle_t cycle_now, cycle_delta; - struct clocksource *clock; - s64 nsec; - - clock = tk->clock; - cycle_now = clock->read(clock); - cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; - tk->cycle_last = clock->cycle_last = cycle_now; - - tk->xtime_nsec += cycle_delta * tk->mult; - - /* If arch requires, add in get_arch_timeoffset() */ - tk->xtime_nsec += (u64)get_arch_timeoffset() << tk->shift; - - tk_normalize_xtime(tk); - - nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); - timespec_add_ns(&tk->raw_time, nsec); + 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.clock->max_raw_delta); + tk->tkr_mono.cycle_last = cycle_now; + tk->tkr_raw.cycle_last = cycle_now; + + while (delta > 0) { + u64 max = tk->tkr_mono.clock->max_cycles; + u64 incr = delta < max ? delta : max; + + tk->tkr_mono.xtime_nsec += incr * tk->tkr_mono.mult; + tk->tkr_raw.xtime_nsec += incr * tk->tkr_raw.mult; + tk_normalize_xtime(tk); + delta -= incr; + } + tk_update_coarse_nsecs(tk); } /** - * __getnstimeofday - Returns the time of day in a timespec. + * ktime_get_real_ts64 - Returns the time of day in a timespec64. * @ts: pointer to the timespec to be set * - * Updates the time of day in the timespec. - * Returns 0 on success, or -ve when suspended (timespec will be undefined). + * Returns the time of day in a timespec64 (WARN if suspended). */ -int __getnstimeofday(struct timespec *ts) +void ktime_get_real_ts64(struct timespec64 *ts) { - struct timekeeper *tk = &timekeeper; - unsigned long seq; - s64 nsecs = 0; + struct timekeeper *tk = &tk_core.timekeeper; + unsigned int seq; + u64 nsecs; + + WARN_ON(timekeeping_suspended); do { - seq = read_seqcount_begin(&timekeeper_seq); + seq = read_seqcount_begin(&tk_core.seq); ts->tv_sec = tk->xtime_sec; - nsecs = timekeeping_get_ns(tk); + nsecs = timekeeping_get_ns(&tk->tkr_mono); - } while (read_seqcount_retry(&timekeeper_seq, seq)); + } while (read_seqcount_retry(&tk_core.seq, seq)); ts->tv_nsec = 0; - timespec_add_ns(ts, nsecs); + timespec64_add_ns(ts, nsecs); +} +EXPORT_SYMBOL(ktime_get_real_ts64); - /* - * Do not bail out early, in case there were callers still using - * the value, even in the face of the WARN_ON. - */ - if (unlikely(timekeeping_suspended)) - return -EAGAIN; - return 0; +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(__getnstimeofday); +EXPORT_SYMBOL_GPL(ktime_get); -/** - * getnstimeofday - Returns the time of day in a timespec. - * @ts: pointer to the timespec to be set - * - * Returns the time of day in a timespec (WARN if suspended). - */ -void getnstimeofday(struct timespec *ts) +u32 ktime_get_resolution_ns(void) { - WARN_ON(__getnstimeofday(ts)); + 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(getnstimeofday); +EXPORT_SYMBOL_GPL(ktime_get_resolution_ns); -ktime_t ktime_get(void) +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 = &timekeeper; + struct timekeeper *tk = &tk_core.timekeeper; unsigned int seq; - s64 secs, nsecs; + ktime_t base, *offset = offsets[offs]; + u64 nsecs; WARN_ON(timekeeping_suspended); do { - seq = read_seqcount_begin(&timekeeper_seq); - secs = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; - nsecs = timekeeping_get_ns(tk) + tk->wall_to_monotonic.tv_nsec; + 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); - } while (read_seqcount_retry(&timekeeper_seq, seq)); - /* - * Use ktime_set/ktime_add_ns to create a proper ktime on - * 32-bit architectures without CONFIG_KTIME_SCALAR. - */ - return ktime_add_ns(ktime_set(secs, 0), nsecs); } -EXPORT_SYMBOL_GPL(ktime_get); +EXPORT_SYMBOL_GPL(ktime_get_with_offset); + +ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs) +{ + struct timekeeper *tk = &tk_core.timekeeper; + ktime_t base, *offset = offsets[offs]; + unsigned int seq; + u64 nsecs; + + WARN_ON(timekeeping_suspended); + + do { + seq = read_seqcount_begin(&tk_core.seq); + base = ktime_add(tk->tkr_mono.base, *offset); + nsecs = tk->coarse_nsec; + + } while (read_seqcount_retry(&tk_core.seq, seq)); + + return ktime_add_ns(base, nsecs); +} +EXPORT_SYMBOL_GPL(ktime_get_coarse_with_offset); /** - * ktime_get_ts - get the monotonic clock in timespec format + * ktime_mono_to_any() - convert monotonic 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; + + if (IS_ENABLED(CONFIG_64BIT)) { + /* + * Paired with WRITE_ONCE()s in tk_set_wall_to_mono() and + * tk_update_sleep_time(). + */ + return ktime_add(tmono, READ_ONCE(*offset)); + } + + 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 timespec format in the variable pointed to by @ts. + * in normalized timespec64 format in the variable pointed to by @ts. */ -void ktime_get_ts(struct timespec *ts) +void ktime_get_ts64(struct timespec64 *ts) { - struct timekeeper *tk = &timekeeper; - struct timespec tomono; - s64 nsec; + struct timekeeper *tk = &tk_core.timekeeper; + struct timespec64 tomono; unsigned int seq; + u64 nsec; WARN_ON(timekeeping_suspended); do { - seq = read_seqcount_begin(&timekeeper_seq); + seq = read_seqcount_begin(&tk_core.seq); ts->tv_sec = tk->xtime_sec; - nsec = timekeeping_get_ns(tk); + nsec = timekeeping_get_ns(&tk->tkr_mono); tomono = tk->wall_to_monotonic; - } while (read_seqcount_retry(&timekeeper_seq, seq)); + } while (read_seqcount_retry(&tk_core.seq, seq)); ts->tv_sec += tomono.tv_sec; ts->tv_nsec = 0; - timespec_add_ns(ts, nsec + tomono.tv_nsec); + timespec64_add_ns(ts, nsec + tomono.tv_nsec); } -EXPORT_SYMBOL_GPL(ktime_get_ts); - +EXPORT_SYMBOL_GPL(ktime_get_ts64); /** - * timekeeping_clocktai - Returns the TAI time of day in a timespec - * @ts: pointer to the timespec to be set + * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC * - * Returns the time of day in a timespec. + * 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. */ -void timekeeping_clocktai(struct timespec *ts) +time64_t ktime_get_seconds(void) { - struct timekeeper *tk = &timekeeper; - unsigned long seq; - u64 nsecs; + struct timekeeper *tk = &tk_core.timekeeper; WARN_ON(timekeeping_suspended); + return tk->ktime_sec; +} +EXPORT_SYMBOL_GPL(ktime_get_seconds); - do { - seq = read_seqcount_begin(&timekeeper_seq); +/** + * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME + * + * Returns the wall clock seconds since 1970. + * + * 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; - ts->tv_sec = tk->xtime_sec + tk->tai_offset; - nsecs = timekeeping_get_ns(tk); + if (IS_ENABLED(CONFIG_64BIT)) + return tk->xtime_sec; - } while (read_seqcount_retry(&timekeeper_seq, seq)); + do { + seq = read_seqcount_begin(&tk_core.seq); + seconds = tk->xtime_sec; - ts->tv_nsec = 0; - timespec_add_ns(ts, nsecs); + } while (read_seqcount_retry(&tk_core.seq, seq)); + return seconds; } -EXPORT_SYMBOL(timekeeping_clocktai); - +EXPORT_SYMBOL_GPL(ktime_get_real_seconds); /** - * ktime_get_clocktai - Returns the TAI time of day in a ktime + * __ktime_get_real_seconds - Unprotected access to CLOCK_REALTIME seconds + * + * The same as ktime_get_real_seconds() but without the sequence counter + * protection. This function is used in restricted contexts like the x86 MCE + * handler and in KGDB. It's unprotected on 32-bit vs. concurrent half + * completed modification and only to be used for such critical contexts. * - * Returns the time of day in a ktime. + * Returns: Racy snapshot of the CLOCK_REALTIME seconds value */ -ktime_t ktime_get_clocktai(void) +noinstr time64_t __ktime_get_real_seconds(void) { - struct timespec ts; + struct timekeeper *tk = &tk_core.timekeeper; - timekeeping_clocktai(&ts); - return timespec_to_ktime(ts); + return tk->xtime_sec; } -EXPORT_SYMBOL(ktime_get_clocktai); - -#ifdef CONFIG_NTP_PPS /** - * getnstime_raw_and_real - get day and raw monotonic time in timespec format - * @ts_raw: pointer to the timespec to be set to raw monotonic time - * @ts_real: pointer to the timespec to be set to the time of day - * - * This function reads both the time of day and raw monotonic time at the - * same time atomically and stores the resulting timestamps in timespec - * format. + * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter + * @systime_snapshot: pointer to struct receiving the system time snapshot */ -void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real) +void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot) { - struct timekeeper *tk = &timekeeper; - unsigned long seq; - s64 nsecs_raw, nsecs_real; + struct timekeeper *tk = &tk_core.timekeeper; + unsigned int seq; + ktime_t base_raw; + ktime_t base_real; + ktime_t base_boot; + u64 nsec_raw; + u64 nsec_real; + u64 now; WARN_ON_ONCE(timekeeping_suspended); do { - seq = read_seqcount_begin(&timekeeper_seq); + seq = read_seqcount_begin(&tk_core.seq); + now = tk_clock_read(&tk->tkr_mono); + systime_snapshot->cs_id = tk->tkr_mono.clock->id; + 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_boot = ktime_add(tk->tkr_mono.base, + tk_core.timekeeper.offs_boot); + 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->boot = ktime_add_ns(base_boot, nsec_real); + systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw); +} +EXPORT_SYMBOL_GPL(ktime_get_snapshot); - *ts_raw = tk->raw_time; - ts_real->tv_sec = tk->xtime_sec; - ts_real->tv_nsec = 0; +/* Scale base by mult/div checking for overflow */ +static int scale64_check_overflow(u64 mult, u64 div, u64 *base) +{ + u64 tmp, rem; - nsecs_raw = timekeeping_get_ns_raw(tk); - nsecs_real = timekeeping_get_ns(tk); + tmp = div64_u64_rem(*base, div, &rem); - } while (read_seqcount_retry(&timekeeper_seq, seq)); + if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) || + ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem))) + return -EOVERFLOW; + tmp *= mult; - timespec_add_ns(ts_raw, nsecs_raw); - timespec_add_ns(ts_real, nsecs_real); + rem = div64_u64(rem * mult, div); + *base = tmp + rem; + return 0; } -EXPORT_SYMBOL(getnstime_raw_and_real); - -#endif /* CONFIG_NTP_PPS */ /** - * do_gettimeofday - Returns the time of day in a timeval - * @tv: pointer to the timeval to be set + * 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 * - * NOTE: Users should be converted to using getnstimeofday() + * 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. */ -void do_gettimeofday(struct timeval *tv) +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 timespec now; + 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); + } - getnstimeofday(&now); - tv->tv_sec = now.tv_sec; - tv->tv_usec = now.tv_nsec/1000; + return 0; } -EXPORT_SYMBOL(do_gettimeofday); -/** - * do_settimeofday - Sets the time of day - * @tv: pointer to the timespec variable containing the new time +/* + * timestamp_in_interval - true if ts is chronologically in [start, end] * - * Sets the time of day to the new time and update NTP and notify hrtimers + * True if ts occurs chronologically at or after start, and before or at end. */ -int do_settimeofday(const struct timespec *tv) +static bool timestamp_in_interval(u64 start, u64 end, u64 ts) { - struct timekeeper *tk = &timekeeper; - struct timespec ts_delta, xt; - unsigned long flags; + if (ts >= start && ts <= end) + return true; + if (start > end && (ts >= start || ts <= end)) + return true; + return false; +} - if (!timespec_valid_strict(tv)) - return -EINVAL; +static bool convert_clock(u64 *val, u32 numerator, u32 denominator) +{ + u64 rem, res; - raw_spin_lock_irqsave(&timekeeper_lock, flags); - write_seqcount_begin(&timekeeper_seq); + if (!numerator || !denominator) + return false; - timekeeping_forward_now(tk); + res = div64_u64_rem(*val, denominator, &rem) * numerator; + *val = res + div_u64(rem * numerator, denominator); + return true; +} - xt = tk_xtime(tk); - ts_delta.tv_sec = tv->tv_sec - xt.tv_sec; - ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec; +static bool convert_base_to_cs(struct system_counterval_t *scv) +{ + struct clocksource *cs = tk_core.timekeeper.tkr_mono.clock; + struct clocksource_base *base; + u32 num, den; - tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, ts_delta)); + /* The timestamp was taken from the time keeper clock source */ + if (cs->id == scv->cs_id) + return true; - tk_set_xtime(tk, tv); + /* + * Check whether cs_id matches the base clock. Prevent the compiler from + * re-evaluating @base as the clocksource might change concurrently. + */ + base = READ_ONCE(cs->base); + if (!base || base->id != scv->cs_id) + return false; - timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); + num = scv->use_nsecs ? cs->freq_khz : base->numerator; + den = scv->use_nsecs ? USEC_PER_SEC : base->denominator; - write_seqcount_end(&timekeeper_seq); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); + if (!convert_clock(&scv->cycles, num, den)) + return false; - /* signal hrtimers about time change */ - clock_was_set(); + scv->cycles += base->offset; + return true; +} - return 0; +static bool convert_cs_to_base(u64 *cycles, enum clocksource_ids base_id) +{ + struct clocksource *cs = tk_core.timekeeper.tkr_mono.clock; + struct clocksource_base *base; + + /* + * Check whether base_id matches the base clock. Prevent the compiler from + * re-evaluating @base as the clocksource might change concurrently. + */ + base = READ_ONCE(cs->base); + if (!base || base->id != base_id) + return false; + + *cycles -= base->offset; + if (!convert_clock(cycles, base->denominator, base->numerator)) + return false; + return true; +} + +static bool convert_ns_to_cs(u64 *delta) +{ + struct tk_read_base *tkr = &tk_core.timekeeper.tkr_mono; + + if (BITS_TO_BYTES(fls64(*delta) + tkr->shift) >= sizeof(*delta)) + return false; + + *delta = div_u64((*delta << tkr->shift) - tkr->xtime_nsec, tkr->mult); + return true; } -EXPORT_SYMBOL(do_settimeofday); /** - * timekeeping_inject_offset - Adds or subtracts from the current time. - * @tv: pointer to the timespec variable containing the offset + * ktime_real_to_base_clock() - Convert CLOCK_REALTIME timestamp to a base clock timestamp + * @treal: CLOCK_REALTIME timestamp to convert + * @base_id: base clocksource id + * @cycles: pointer to store the converted base clock timestamp * - * Adds or subtracts an offset value from the current time. + * Converts a supplied, future realtime clock value to the corresponding base clock value. + * + * Return: true if the conversion is successful, false otherwise. */ -int timekeeping_inject_offset(struct timespec *ts) +bool ktime_real_to_base_clock(ktime_t treal, enum clocksource_ids base_id, u64 *cycles) { - struct timekeeper *tk = &timekeeper; - unsigned long flags; - struct timespec tmp; - int ret = 0; + struct timekeeper *tk = &tk_core.timekeeper; + unsigned int seq; + u64 delta; - if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) - return -EINVAL; + do { + seq = read_seqcount_begin(&tk_core.seq); + if ((u64)treal < tk->tkr_mono.base_real) + return false; + delta = (u64)treal - tk->tkr_mono.base_real; + if (!convert_ns_to_cs(&delta)) + return false; + *cycles = tk->tkr_mono.cycle_last + delta; + if (!convert_cs_to_base(cycles, base_id)) + return false; + } while (read_seqcount_retry(&tk_core.seq, seq)); + + return true; +} +EXPORT_SYMBOL_GPL(ktime_real_to_base_clock); - raw_spin_lock_irqsave(&timekeeper_lock, flags); - write_seqcount_begin(&timekeeper_seq); +/** + * 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; - timekeeping_forward_now(tk); + 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; - /* Make sure the proposed value is valid */ - tmp = timespec_add(tk_xtime(tk), *ts); - if (!timespec_valid_strict(&tmp)) { - ret = -EINVAL; - goto error; - } + /* + * Verify that the clocksource ID associated with the captured + * system counter value is the same as for the currently + * installed timekeeper clocksource + */ + if (system_counterval.cs_id == CSID_GENERIC || + !convert_base_to_cs(&system_counterval)) + return -ENODEV; + cycles = system_counterval.cycles; - tk_xtime_add(tk, ts); - tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, *ts)); + /* + * 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 (!timestamp_in_interval(interval_start, now, cycles)) { + 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; + } -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); + base_real = ktime_add(tk->tkr_mono.base, + tk_core.timekeeper.offs_real); + base_raw = tk->tkr_raw.base; - write_seqcount_end(&timekeeper_seq); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); + nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, cycles); + nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, cycles); + } while (read_seqcount_retry(&tk_core.seq, seq)); - /* signal hrtimers about time change */ - clock_was_set(); + xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real); + xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw); - return ret; + /* + * 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 is not before the provided + * history reference and that the history doesn't cross a + * clocksource change + */ + if (!history_begin || + !timestamp_in_interval(history_begin->cycles, + cycles, system_counterval.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(timekeeping_inject_offset); +EXPORT_SYMBOL_GPL(get_device_system_crosststamp); + +/** + * timekeeping_clocksource_has_base - Check whether the current clocksource + * is based on given a base clock + * @id: base clocksource ID + * + * Note: The return value is a snapshot which can become invalid right + * after the function returns. + * + * Return: true if the timekeeper clocksource has a base clock with @id, + * false otherwise + */ +bool timekeeping_clocksource_has_base(enum clocksource_ids id) +{ + /* + * This is a snapshot, so no point in using the sequence + * count. Just prevent the compiler from re-evaluating @base as the + * clocksource might change concurrently. + */ + struct clocksource_base *base = READ_ONCE(tk_core.timekeeper.tkr_mono.clock->base); + return base ? base->id == id : false; +} +EXPORT_SYMBOL_GPL(timekeeping_clocksource_has_base); /** - * timekeeping_get_tai_offset - Returns current TAI offset from UTC + * 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 */ -s32 timekeeping_get_tai_offset(void) +int do_settimeofday64(const struct timespec64 *ts) { - struct timekeeper *tk = &timekeeper; - unsigned int seq; - s32 ret; + struct timespec64 ts_delta, xt; - do { - seq = read_seqcount_begin(&timekeeper_seq); - ret = tk->tai_offset; - } while (read_seqcount_retry(&timekeeper_seq, seq)); + if (!timespec64_valid_settod(ts)) + return -EINVAL; - return ret; + scoped_guard (raw_spinlock_irqsave, &tk_core.lock) { + struct timekeeper *tks = &tk_core.shadow_timekeeper; + + timekeeping_forward_now(tks); + + xt = tk_xtime(tks); + ts_delta = timespec64_sub(*ts, xt); + + if (timespec64_compare(&tks->wall_to_monotonic, &ts_delta) > 0) { + timekeeping_restore_shadow(&tk_core); + return -EINVAL; + } + + tk_set_wall_to_mono(tks, timespec64_sub(tks->wall_to_monotonic, ts_delta)); + tk_set_xtime(tks, ts); + timekeeping_update_from_shadow(&tk_core, TK_UPDATE_ALL); + } + + /* Signal hrtimers about time change */ + clock_was_set(CLOCK_SET_WALL); + + audit_tk_injoffset(ts_delta); + add_device_randomness(ts, sizeof(*ts)); + return 0; +} +EXPORT_SYMBOL(do_settimeofday64); + +static inline bool timekeeper_is_core_tk(struct timekeeper *tk) +{ + return !IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS) || tk->id == TIMEKEEPER_CORE; } /** - * __timekeeping_set_tai_offset - Lock free worker function + * __timekeeping_inject_offset - Adds or subtracts from the current time. + * @tkd: Pointer to the timekeeper to modify + * @ts: Pointer to the timespec variable containing the offset * + * Adds or subtracts an offset value from the current time. */ -static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset) +static int __timekeeping_inject_offset(struct tk_data *tkd, const struct timespec64 *ts) { - tk->tai_offset = tai_offset; - tk->offs_tai = ktime_sub(tk->offs_real, ktime_set(tai_offset, 0)); + struct timekeeper *tks = &tkd->shadow_timekeeper; + struct timespec64 tmp; + + if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC) + return -EINVAL; + + timekeeping_forward_now(tks); + + if (timekeeper_is_core_tk(tks)) { + /* Make sure the proposed value is valid */ + tmp = timespec64_add(tk_xtime(tks), *ts); + if (timespec64_compare(&tks->wall_to_monotonic, ts) > 0 || + !timespec64_valid_settod(&tmp)) { + timekeeping_restore_shadow(tkd); + return -EINVAL; + } + + tk_xtime_add(tks, ts); + tk_set_wall_to_mono(tks, timespec64_sub(tks->wall_to_monotonic, *ts)); + } else { + struct tk_read_base *tkr_mono = &tks->tkr_mono; + ktime_t now, offs; + + /* Get the current time */ + now = ktime_add_ns(tkr_mono->base, timekeeping_get_ns(tkr_mono)); + /* Add the relative offset change */ + offs = ktime_add(tks->offs_aux, timespec64_to_ktime(*ts)); + + /* Prevent that the resulting time becomes negative */ + if (ktime_add(now, offs) < 0) { + timekeeping_restore_shadow(tkd); + return -EINVAL; + } + tk_update_aux_offs(tks, offs); + } + + timekeeping_update_from_shadow(tkd, TK_UPDATE_ALL); + return 0; } -/** - * timekeeping_set_tai_offset - Sets the current TAI offset from UTC +static int timekeeping_inject_offset(const struct timespec64 *ts) +{ + int ret; + + scoped_guard (raw_spinlock_irqsave, &tk_core.lock) + ret = __timekeeping_inject_offset(&tk_core, ts); + + /* Signal hrtimers about time change */ + if (!ret) + clock_was_set(CLOCK_SET_WALL); + 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_set_tai_offset(s32 tai_offset) +void timekeeping_warp_clock(void) { - struct timekeeper *tk = &timekeeper; - unsigned long flags; + if (sys_tz.tz_minuteswest != 0) { + struct timespec64 adjust; - raw_spin_lock_irqsave(&timekeeper_lock, flags); - write_seqcount_begin(&timekeeper_seq); - __timekeeping_set_tai_offset(tk, tai_offset); - write_seqcount_end(&timekeeper_seq); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); - clock_was_set(); + 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 = &timekeeper; - struct clocksource *new, *old; - unsigned long flags; + struct clocksource *new = data, *old = NULL; - new = (struct clocksource *) data; - - raw_spin_lock_irqsave(&timekeeper_lock, flags); - write_seqcount_begin(&timekeeper_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 the clocksource is in a module, get a module reference. + * Succeeds for built-in code (owner == NULL) as well. Abort if the + * reference can't be acquired. */ - if (try_module_get(new->owner)) { - if (!new->enable || new->enable(new) == 0) { - old = tk->clock; - tk_setup_internals(tk, new); - if (old->disable) - old->disable(old); - module_put(old->owner); - } else { - module_put(new->owner); - } + if (!try_module_get(new->owner)) + return 0; + + /* Abort if the device can't be enabled */ + if (new->enable && new->enable(new) != 0) { + module_put(new->owner); + return 0; } - timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); - write_seqcount_end(&timekeeper_seq); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); + scoped_guard (raw_spinlock_irqsave, &tk_core.lock) { + struct timekeeper *tks = &tk_core.shadow_timekeeper; + + timekeeping_forward_now(tks); + old = tks->tkr_mono.clock; + tk_setup_internals(tks, new); + timekeeping_update_from_shadow(&tk_core, TK_UPDATE_ALL); + } + + tk_aux_update_clocksource(); + + if (old) { + if (old->disable) + old->disable(old); + module_put(old->owner); + } return 0; } @@ -664,68 +1627,88 @@ static int change_clocksource(void *data) */ int timekeeping_notify(struct clocksource *clock) { - struct timekeeper *tk = &timekeeper; + struct timekeeper *tk = &tk_core.timekeeper; - if (tk->clock == clock) + if (tk->tkr_mono.clock == clock) return 0; stop_machine(change_clocksource, clock, NULL); tick_clock_notify(); - return tk->clock == clock ? 0 : -1; + return tk->tkr_mono.clock == clock ? 0 : -1; } /** - * ktime_get_real - get the real (wall-) time in ktime_t format + * ktime_get_raw_ts64 - Returns the raw monotonic time in a timespec + * @ts: pointer to the timespec64 to be set * - * returns the time in ktime_t format + * Returns the raw monotonic time (completely un-modified by ntp) */ -ktime_t ktime_get_real(void) +void ktime_get_raw_ts64(struct timespec64 *ts) { - struct timespec now; + struct timekeeper *tk = &tk_core.timekeeper; + unsigned int seq; + u64 nsecs; - getnstimeofday(&now); + 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)); - return timespec_to_ktime(now); + ts->tv_nsec = 0; + timespec64_add_ns(ts, nsecs); } -EXPORT_SYMBOL_GPL(ktime_get_real); +EXPORT_SYMBOL(ktime_get_raw_ts64); /** - * getrawmonotonic - Returns the raw monotonic time in a timespec - * @ts: pointer to the timespec to be set + * ktime_get_clock_ts64 - Returns time of a clock in a timespec + * @id: POSIX clock ID of the clock to read + * @ts: Pointer to the timespec64 to be set * - * Returns the raw monotonic time (completely un-modified by ntp) + * The timestamp is invalidated (@ts->sec is set to -1) if the + * clock @id is not available. */ -void getrawmonotonic(struct timespec *ts) +void ktime_get_clock_ts64(clockid_t id, struct timespec64 *ts) { - struct timekeeper *tk = &timekeeper; - unsigned long seq; - s64 nsecs; - - do { - seq = read_seqcount_begin(&timekeeper_seq); - nsecs = timekeeping_get_ns_raw(tk); - *ts = tk->raw_time; - - } while (read_seqcount_retry(&timekeeper_seq, seq)); + /* Invalidate time stamp */ + ts->tv_sec = -1; + ts->tv_nsec = 0; - timespec_add_ns(ts, nsecs); + switch (id) { + case CLOCK_REALTIME: + ktime_get_real_ts64(ts); + return; + case CLOCK_MONOTONIC: + ktime_get_ts64(ts); + return; + case CLOCK_MONOTONIC_RAW: + ktime_get_raw_ts64(ts); + return; + case CLOCK_AUX ... CLOCK_AUX_LAST: + if (IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS)) + ktime_get_aux_ts64(id, ts); + return; + default: + WARN_ON_ONCE(1); + } } -EXPORT_SYMBOL(getrawmonotonic); +EXPORT_SYMBOL_GPL(ktime_get_clock_ts64); /** * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres */ int timekeeping_valid_for_hres(void) { - struct timekeeper *tk = &timekeeper; - unsigned long seq; + struct timekeeper *tk = &tk_core.timekeeper; + unsigned int seq; int ret; do { - seq = read_seqcount_begin(&timekeeper_seq); + seq = read_seqcount_begin(&tk_core.seq); - ret = tk->clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; + ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; - } while (read_seqcount_retry(&timekeeper_seq, seq)); + } while (read_seqcount_retry(&tk_core.seq, seq)); return ret; } @@ -735,22 +1718,23 @@ int timekeeping_valid_for_hres(void) */ u64 timekeeping_max_deferment(void) { - struct timekeeper *tk = &timekeeper; - unsigned long seq; + struct timekeeper *tk = &tk_core.timekeeper; + unsigned int seq; u64 ret; do { - seq = read_seqcount_begin(&timekeeper_seq); + seq = read_seqcount_begin(&tk_core.seq); - ret = tk->clock->max_idle_ns; + ret = tk->tkr_mono.clock->max_idle_ns; - } while (read_seqcount_retry(&timekeeper_seq, seq)); + } while (read_seqcount_retry(&tk_core.seq, seq)); return ret; } /** - * read_persistent_clock - Return time from the persistent clock. + * read_persistent_clock64 - Return time from the persistent clock. + * @ts: Pointer to the storage for the readout value * * Weak dummy function for arches that do not yet support it. * Reads the time from the battery backed persistent clock. @@ -758,168 +1742,213 @@ u64 timekeeping_max_deferment(void) * * XXX - Do be sure to remove it once all arches implement it. */ -void __attribute__((weak)) read_persistent_clock(struct timespec *ts) +void __weak read_persistent_clock64(struct timespec64 *ts) { ts->tv_sec = 0; ts->tv_nsec = 0; } /** - * read_boot_clock - Return time of the system start. + * read_persistent_wall_and_boot_offset - Read persistent clock, and also offset + * from the boot. + * @wall_time: current time as returned by persistent clock + * @boot_offset: offset that is defined as wall_time - boot_time * * Weak dummy function for arches that do not yet support it. - * Function to read the exact time the system has been started. - * 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. + * 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 __attribute__((weak)) read_boot_clock(struct timespec *ts) +void __weak __init +read_persistent_wall_and_boot_offset(struct timespec64 *wall_time, + struct timespec64 *boot_offset) { - ts->tv_sec = 0; - ts->tv_nsec = 0; + read_persistent_clock64(wall_time); + *boot_offset = ns_to_timespec64(local_clock()); +} + +static __init void tkd_basic_setup(struct tk_data *tkd, enum timekeeper_ids tk_id, bool valid) +{ + raw_spin_lock_init(&tkd->lock); + seqcount_raw_spinlock_init(&tkd->seq, &tkd->lock); + tkd->timekeeper.id = tkd->shadow_timekeeper.id = tk_id; + tkd->timekeeper.clock_valid = tkd->shadow_timekeeper.clock_valid = valid; } /* + * 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 timekeeper *tk = &timekeeper; + struct timespec64 wall_time, boot_offset, wall_to_mono; + struct timekeeper *tks = &tk_core.shadow_timekeeper; struct clocksource *clock; - unsigned long flags; - struct timespec now, boot, tmp; - - read_persistent_clock(&now); - - if (!timespec_valid_strict(&now)) { - pr_warn("WARNING: Persistent clock returned invalid value!\n" - " Check your CMOS/BIOS settings.\n"); - now.tv_sec = 0; - now.tv_nsec = 0; - } else if (now.tv_sec || now.tv_nsec) - persistent_clock_exist = true; - - read_boot_clock(&boot); - if (!timespec_valid_strict(&boot)) { - pr_warn("WARNING: Boot clock returned invalid value!\n" - " Check your CMOS/BIOS settings.\n"); - boot.tv_sec = 0; - boot.tv_nsec = 0; + + tkd_basic_setup(&tk_core, TIMEKEEPER_CORE, true); + tk_aux_setup(); + + 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}; } - raw_spin_lock_irqsave(&timekeeper_lock, flags); - write_seqcount_begin(&timekeeper_seq); + 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); + + guard(raw_spinlock_irqsave)(&tk_core.lock); + ntp_init(); clock = clocksource_default_clock(); if (clock->enable) clock->enable(clock); - tk_setup_internals(tk, clock); - - tk_set_xtime(tk, &now); - tk->raw_time.tv_sec = 0; - tk->raw_time.tv_nsec = 0; - if (boot.tv_sec == 0 && boot.tv_nsec == 0) - boot = tk_xtime(tk); + tk_setup_internals(tks, clock); - set_normalized_timespec(&tmp, -boot.tv_sec, -boot.tv_nsec); - tk_set_wall_to_mono(tk, tmp); + tk_set_xtime(tks, &wall_time); + tks->raw_sec = 0; - tmp.tv_sec = 0; - tmp.tv_nsec = 0; - tk_set_sleep_time(tk, tmp); + tk_set_wall_to_mono(tks, wall_to_mono); - memcpy(&shadow_timekeeper, &timekeeper, sizeof(timekeeper)); - - write_seqcount_end(&timekeeper_seq); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); + timekeeping_update_from_shadow(&tk_core, TK_CLOCK_WAS_SET); } -/* time in seconds when suspend began */ -static struct timespec timekeeping_suspend_time; +/* 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 + * @tk: Pointer to the timekeeper to be updated + * @delta: Pointer to the delta value in timespec64 format * * Takes a timespec offset measuring a suspend interval and properly * adds the sleep offset to the timekeeping variables. */ static void __timekeeping_inject_sleeptime(struct timekeeper *tk, - struct timespec *delta) + const struct timespec64 *delta) { - if (!timespec_valid_strict(delta)) { - printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid " - "sleep delta value!\n"); + 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, timespec_sub(tk->wall_to_monotonic, *delta)); - tk_set_sleep_time(tk, timespec_add(tk->total_sleep_time, *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_sleeptime - Adds suspend interval to timeekeeping values - * @delta: pointer to a timespec delta value + * 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_clock + * 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_sleeptime(struct timespec *delta) +void timekeeping_inject_sleeptime64(const struct timespec64 *delta) { - struct timekeeper *tk = &timekeeper; - unsigned long flags; - - /* - * Make sure we don't set the clock twice, as timekeeping_resume() - * already did it - */ - if (has_persistent_clock()) - return; - - raw_spin_lock_irqsave(&timekeeper_lock, flags); - write_seqcount_begin(&timekeeper_seq); - - timekeeping_forward_now(tk); + scoped_guard(raw_spinlock_irqsave, &tk_core.lock) { + struct timekeeper *tks = &tk_core.shadow_timekeeper; - __timekeeping_inject_sleeptime(tk, delta); - - timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); - - write_seqcount_end(&timekeeper_seq); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); + suspend_timing_needed = false; + timekeeping_forward_now(tks); + __timekeeping_inject_sleeptime(tks, delta); + timekeeping_update_from_shadow(&tk_core, TK_UPDATE_ALL); + } - /* signal hrtimers about time change */ - clock_was_set(); + /* Signal hrtimers about time change */ + clock_was_set(CLOCK_SET_WALL | CLOCK_SET_BOOT); } +#endif /** * timekeeping_resume - Resumes the generic timekeeping subsystem. - * - * This is for the generic clocksource timekeeping. - * xtime/wall_to_monotonic/jiffies/etc are - * still managed by arch specific suspend/resume code. */ -static void timekeeping_resume(void) +void timekeeping_resume(void) { - struct timekeeper *tk = &timekeeper; - struct clocksource *clock = tk->clock; + struct timekeeper *tks = &tk_core.shadow_timekeeper; + struct clocksource *clock = tks->tkr_mono.clock; + struct timespec64 ts_new, ts_delta; + bool inject_sleeptime = false; + u64 cycle_now, nsec; unsigned long flags; - struct timespec ts_new, ts_delta; - cycle_t cycle_now, cycle_delta; - bool suspendtime_found = false; - read_persistent_clock(&ts_new); + read_persistent_clock64(&ts_new); clockevents_resume(); clocksource_resume(); - raw_spin_lock_irqsave(&timekeeper_lock, flags); - write_seqcount_begin(&timekeeper_seq); + raw_spin_lock_irqsave(&tk_core.lock, flags); /* * After system resumes, we need to calculate the suspended time and @@ -933,63 +1962,53 @@ static void timekeeping_resume(void) * 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 = clock->read(clock); - if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) && - cycle_now > clock->cycle_last) { - u64 num, max = ULLONG_MAX; - u32 mult = clock->mult; - u32 shift = clock->shift; - s64 nsec = 0; - - cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; - - /* - * "cycle_delta * mutl" may cause 64 bits overflow, if the - * suspended time is too long. In that case we need do the - * 64 bits math carefully - */ - do_div(max, mult); - if (cycle_delta > max) { - num = div64_u64(cycle_delta, max); - nsec = (((u64) max * mult) >> shift) * num; - cycle_delta -= num * max; - } - nsec += ((u64) cycle_delta * mult) >> shift; - - ts_delta = ns_to_timespec(nsec); - suspendtime_found = true; - } else if (timespec_compare(&ts_new, &timekeeping_suspend_time) > 0) { - ts_delta = timespec_sub(ts_new, timekeeping_suspend_time); - suspendtime_found = true; + cycle_now = tk_clock_read(&tks->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 (suspendtime_found) - __timekeeping_inject_sleeptime(tk, &ts_delta); + if (inject_sleeptime) { + suspend_timing_needed = false; + __timekeeping_inject_sleeptime(tks, &ts_delta); + } /* Re-base the last cycle value */ - tk->cycle_last = clock->cycle_last = cycle_now; - tk->ntp_error = 0; + tks->tkr_mono.cycle_last = cycle_now; + tks->tkr_raw.cycle_last = cycle_now; + + tks->ntp_error = 0; timekeeping_suspended = 0; - timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET); - write_seqcount_end(&timekeeper_seq); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); + timekeeping_update_from_shadow(&tk_core, TK_CLOCK_WAS_SET); + raw_spin_unlock_irqrestore(&tk_core.lock, flags); touch_softlockup_watchdog(); - clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); + /* Resume the clockevent device(s) and hrtimers */ + tick_resume(); + /* Notify timerfd as resume is equivalent to clock_was_set() */ + timerfd_resume(); +} - /* Resume hrtimers */ - hrtimers_resume(); +static void timekeeping_syscore_resume(void *data) +{ + timekeeping_resume(); } -static int timekeeping_suspend(void) +int timekeeping_suspend(void) { - struct timekeeper *tk = &timekeeper; + struct timekeeper *tks = &tk_core.shadow_timekeeper; + struct timespec64 delta, delta_delta; + static struct timespec64 old_delta; + struct clocksource *curr_clock; unsigned long flags; - struct timespec delta, delta_delta; - static struct timespec old_delta; + u64 cycle_now; - read_persistent_clock(&timekeeping_suspend_time); + read_persistent_clock64(&timekeeping_suspend_time); /* * On some systems the persistent_clock can not be detected at @@ -997,182 +2016,103 @@ static int timekeeping_suspend(void) * value returned, update the persistent_clock_exists flag. */ if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec) - persistent_clock_exist = true; + persistent_clock_exists = true; - raw_spin_lock_irqsave(&timekeeper_lock, flags); - write_seqcount_begin(&timekeeper_seq); - timekeeping_forward_now(tk); + suspend_timing_needed = true; + + raw_spin_lock_irqsave(&tk_core.lock, flags); + timekeeping_forward_now(tks); timekeeping_suspended = 1; /* - * 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. + * 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. */ - delta = timespec_sub(tk_xtime(tk), timekeeping_suspend_time); - delta_delta = timespec_sub(delta, old_delta); - if (abs(delta_delta.tv_sec) >= 2) { + curr_clock = tks->tkr_mono.clock; + cycle_now = tks->tkr_mono.cycle_last; + clocksource_start_suspend_timing(curr_clock, cycle_now); + + if (persistent_clock_exists) { /* - * if delta_delta is too large, assume time correction - * has occured and set old_delta to the current delta. + * 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. */ - old_delta = delta; - } else { - /* Otherwise try to adjust old_system to compensate */ - timekeeping_suspend_time = - timespec_add(timekeeping_suspend_time, delta_delta); + delta = timespec64_sub(tk_xtime(tks), 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); + } } - write_seqcount_end(&timekeeper_seq); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); - clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); + timekeeping_update_from_shadow(&tk_core, 0); + halt_fast_timekeeper(tks); + raw_spin_unlock_irqrestore(&tk_core.lock, flags); + + tick_suspend(); clocksource_suspend(); clockevents_suspend(); return 0; } +static int timekeeping_syscore_suspend(void *data) +{ + return timekeeping_suspend(); +} + /* sysfs resume/suspend bits for timekeeping */ -static struct syscore_ops timekeeping_syscore_ops = { - .resume = timekeeping_resume, - .suspend = timekeeping_suspend, +static const struct syscore_ops timekeeping_syscore_ops = { + .resume = timekeeping_syscore_resume, + .suspend = timekeeping_syscore_suspend, +}; + +static struct syscore timekeeping_syscore = { + .ops = &timekeeping_syscore_ops, }; static int __init timekeeping_init_ops(void) { - register_syscore_ops(&timekeeping_syscore_ops); + register_syscore(&timekeeping_syscore); return 0; } - device_initcall(timekeeping_init_ops); /* - * If the error is already larger, we look ahead even further - * to compensate for late or lost adjustments. + * Apply a multiplier adjustment to the timekeeper */ -static __always_inline int timekeeping_bigadjust(struct timekeeper *tk, - s64 error, s64 *interval, - s64 *offset) +static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk, + s64 offset, + s32 mult_adj) { - s64 tick_error, i; - u32 look_ahead, adj; - s32 error2, mult; - - /* - * Use the current error value to determine how much to look ahead. - * The larger the error the slower we adjust for it to avoid problems - * with losing too many ticks, otherwise we would overadjust and - * produce an even larger error. The smaller the adjustment the - * faster we try to adjust for it, as lost ticks can do less harm - * here. This is tuned so that an error of about 1 msec is adjusted - * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks). - */ - error2 = tk->ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ); - error2 = abs(error2); - for (look_ahead = 0; error2 > 0; look_ahead++) - error2 >>= 2; - - /* - * Now calculate the error in (1 << look_ahead) ticks, but first - * remove the single look ahead already included in the error. - */ - tick_error = ntp_tick_length() >> (tk->ntp_error_shift + 1); - tick_error -= tk->xtime_interval >> 1; - error = ((error - tick_error) >> look_ahead) + tick_error; - - /* Finally calculate the adjustment shift value. */ - i = *interval; - mult = 1; - if (error < 0) { - error = -error; - *interval = -*interval; - *offset = -*offset; - mult = -1; - } - for (adj = 0; error > i; adj++) - error >>= 1; + s64 interval = tk->cycle_interval; - *interval <<= adj; - *offset <<= adj; - return mult << adj; -} - -/* - * Adjust the multiplier to reduce the error value, - * this is optimized for the most common adjustments of -1,0,1, - * for other values we can do a bit more work. - */ -static void timekeeping_adjust(struct timekeeper *tk, s64 offset) -{ - s64 error, interval = tk->cycle_interval; - int adj; - - /* - * The point of this is to check if the error is greater than half - * an interval. - * - * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs. - * - * Note we subtract one in the shift, so that error is really error*2. - * This "saves" dividing(shifting) interval twice, but keeps the - * (error > interval) comparison as still measuring if error is - * larger than half an interval. - * - * Note: It does not "save" on aggravation when reading the code. - */ - error = tk->ntp_error >> (tk->ntp_error_shift - 1); - if (error > interval) { - /* - * We now divide error by 4(via shift), which checks if - * the error is greater than twice the interval. - * If it is greater, we need a bigadjust, if its smaller, - * we can adjust by 1. - */ - error >>= 2; - /* - * XXX - In update_wall_time, we round up to the next - * nanosecond, and store the amount rounded up into - * the error. This causes the likely below to be unlikely. - * - * The proper fix is to avoid rounding up by using - * the high precision tk->xtime_nsec instead of - * xtime.tv_nsec everywhere. Fixing this will take some - * time. - */ - if (likely(error <= interval)) - adj = 1; - else - adj = timekeeping_bigadjust(tk, error, &interval, &offset); - } else { - if (error < -interval) { - /* See comment above, this is just switched for the negative */ - error >>= 2; - if (likely(error >= -interval)) { - adj = -1; - interval = -interval; - offset = -offset; - } else { - adj = timekeeping_bigadjust(tk, error, &interval, &offset); - } - } else { - goto out_adjust; - } + 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; } - if (unlikely(tk->clock->maxadj && - (tk->mult + adj > tk->clock->mult + tk->clock->maxadj))) { - printk_once(KERN_WARNING - "Adjusting %s more than 11%% (%ld vs %ld)\n", - tk->clock->name, (long)tk->mult + adj, - (long)tk->clock->mult + tk->clock->maxadj); - } /* * So the following can be confusing. * - * To keep things simple, lets assume adj == 1 for now. + * To keep things simple, lets assume mult_adj == 1 for now. * - * When adj != 1, remember that the interval and offset values + * 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 @@ -1211,181 +2151,192 @@ static void timekeeping_adjust(struct timekeeper *tk, s64 offset) * xtime_nsec_1 = offset + xtime_nsec_2 * Which gives us: * xtime_nsec_2 = xtime_nsec_1 - offset - * Which simplfies to: + * Which simplifies to: * xtime_nsec -= offset - * - * XXX - TODO: Doc ntp_error calculation. */ - tk->mult += adj; + 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->xtime_nsec -= offset; - tk->ntp_error -= (interval - offset) << tk->ntp_error_shift; + 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) +{ + u64 ntp_tl = ntp_tick_length(tk->id); + 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_tl)) { + mult = tk->tkr_mono.mult - tk->ntp_err_mult; + } else { + tk->ntp_tick = ntp_tl; + 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); + } -out_adjust: /* * It may be possible that when we entered this function, xtime_nsec * was very small. Further, if we're slightly speeding the clocksource * in the code above, its possible the required corrective factor to * xtime_nsec could cause it to underflow. * - * Now, since we already accumulated the second, cannot simply roll - * the accumulated second back, since the NTP subsystem has been - * notified via second_overflow. So instead we push xtime_nsec forward - * by the amount we underflowed, and add that amount into the error. - * - * We'll correct this error next time through this function, when - * xtime_nsec is not as small. + * 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->xtime_nsec < 0)) { - s64 neg = -(s64)tk->xtime_nsec; - tk->xtime_nsec = 0; - tk->ntp_error += neg << tk->ntp_error_shift; + 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 a the nsecs greater then a second + * 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->shift; - unsigned int action = 0; + u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift; + unsigned int clock_set = 0; - while (tk->xtime_nsec >= nsecps) { + while (tk->tkr_mono.xtime_nsec >= nsecps) { int leap; - tk->xtime_nsec -= nsecps; + 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); + leap = second_overflow(tk->id, tk->xtime_sec); if (unlikely(leap)) { - struct timespec ts; + struct timespec64 ts; tk->xtime_sec += leap; ts.tv_sec = leap; ts.tv_nsec = 0; tk_set_wall_to_mono(tk, - timespec_sub(tk->wall_to_monotonic, ts)); + timespec64_sub(tk->wall_to_monotonic, ts)); __timekeeping_set_tai_offset(tk, tk->tai_offset - leap); - clock_was_set_delayed(); - action = TK_CLOCK_WAS_SET; + clock_set = TK_CLOCK_WAS_SET; } } - return action; + return clock_set; } -/** +/* * logarithmic_accumulation - shifted accumulation of cycles * * This functions accumulates a shifted interval of cycles into - * into a shifted interval nanoseconds. Allows for O(log) accumulation + * a shifted interval nanoseconds. Allows for O(log) accumulation * loop. * * Returns the unconsumed cycles. */ -static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset, - u32 shift) +static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset, + u32 shift, unsigned int *clock_set) { - cycle_t interval = tk->cycle_interval << shift; - u64 raw_nsecs; + u64 interval = tk->cycle_interval << shift; + u64 snsec_per_sec; - /* If the offset is smaller then a shifted interval, do nothing */ + /* If the offset is smaller than a shifted interval, do nothing */ if (offset < interval) return offset; /* Accumulate one shifted interval */ offset -= interval; - tk->cycle_last += interval; + tk->tkr_mono.cycle_last += interval; + tk->tkr_raw.cycle_last += interval; - tk->xtime_nsec += tk->xtime_interval << shift; - accumulate_nsecs_to_secs(tk); + tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift; + *clock_set |= accumulate_nsecs_to_secs(tk); /* Accumulate raw time */ - raw_nsecs = (u64)tk->raw_interval << shift; - raw_nsecs += tk->raw_time.tv_nsec; - if (raw_nsecs >= NSEC_PER_SEC) { - u64 raw_secs = raw_nsecs; - raw_nsecs = do_div(raw_secs, NSEC_PER_SEC); - tk->raw_time.tv_sec += raw_secs; + 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++; } - tk->raw_time.tv_nsec = raw_nsecs; /* Accumulate error between NTP and clock interval */ - tk->ntp_error += ntp_tick_length() << shift; + tk->ntp_error += tk->ntp_tick << shift; tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) << (tk->ntp_error_shift + shift); return offset; } -#ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD -static inline void old_vsyscall_fixup(struct timekeeper *tk) -{ - s64 remainder; - - /* - * Store only full nanoseconds into xtime_nsec after rounding - * it up and add the remainder to the error difference. - * XXX - This is necessary to avoid small 1ns inconsistnecies caused - * by truncating the remainder in vsyscalls. However, it causes - * additional work to be done in timekeeping_adjust(). Once - * the vsyscall implementations are converted to use xtime_nsec - * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD - * users are removed, this can be killed. - */ - remainder = tk->xtime_nsec & ((1ULL << tk->shift) - 1); - tk->xtime_nsec -= remainder; - tk->xtime_nsec += 1ULL << tk->shift; - tk->ntp_error += remainder << tk->ntp_error_shift; - -} -#else -#define old_vsyscall_fixup(tk) -#endif - - - -/** - * update_wall_time - Uses the current clocksource to increment the wall time - * +/* + * timekeeping_advance - Updates the timekeeper to the current time and + * current NTP tick length */ -static void update_wall_time(void) +static bool __timekeeping_advance(struct tk_data *tkd, enum timekeeping_adv_mode mode) { - struct clocksource *clock; - struct timekeeper *real_tk = &timekeeper; - struct timekeeper *tk = &shadow_timekeeper; - cycle_t offset; + struct timekeeper *tk = &tkd->shadow_timekeeper; + struct timekeeper *real_tk = &tkd->timekeeper; + unsigned int clock_set = 0; int shift = 0, maxshift; - unsigned int action; - unsigned long flags; - - raw_spin_lock_irqsave(&timekeeper_lock, flags); + u64 offset, orig_offset; /* Make sure we're fully resumed: */ if (unlikely(timekeeping_suspended)) - goto out; - - clock = real_tk->clock; - -#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET - offset = real_tk->cycle_interval; -#else - offset = (clock->read(clock) - clock->cycle_last) & clock->mask; -#endif + return false; + offset = clocksource_delta(tk_clock_read(&tk->tkr_mono), + tk->tkr_mono.cycle_last, tk->tkr_mono.mask, + tk->tkr_mono.clock->max_raw_delta); + orig_offset = offset; /* Check if there's really nothing to do */ - if (offset < real_tk->cycle_interval) - goto out; + if (offset < real_tk->cycle_interval && mode == TK_ADV_TICK) + return false; /* * With NO_HZ we may have to accumulate many cycle_intervals @@ -1398,184 +2349,192 @@ static void update_wall_time(void) 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; + maxshift = (64 - (ilog2(ntp_tick_length(tk->id)) + 1)) - 1; shift = min(shift, maxshift); while (offset >= tk->cycle_interval) { - offset = logarithmic_accumulation(tk, offset, shift); + offset = logarithmic_accumulation(tk, offset, shift, &clock_set); if (offset < tk->cycle_interval<<shift) shift--; } - /* correct the clock when NTP error is too big */ + /* Adjust the multiplier to correct NTP error */ timekeeping_adjust(tk, offset); /* - * XXX This can be killed once everyone converts - * to the new update_vsyscall. - */ - old_vsyscall_fixup(tk); - - /* * Finally, make sure that after the rounding * xtime_nsec isn't larger than NSEC_PER_SEC */ - action = accumulate_nsecs_to_secs(tk); + clock_set |= accumulate_nsecs_to_secs(tk); - write_seqcount_begin(&timekeeper_seq); - /* Update clock->cycle_last with the new value */ - clock->cycle_last = tk->cycle_last; /* - * 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 timekeeper_seq against one before we start - * updating. + * To avoid inconsistencies caused adjtimex TK_ADV_FREQ calls + * making small negative adjustments to the base xtime_nsec + * value, only update the coarse clocks if we accumulated time */ - memcpy(real_tk, tk, sizeof(*tk)); - timekeeping_update(real_tk, action); - write_seqcount_end(&timekeeper_seq); -out: - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); + if (orig_offset != offset) + tk_update_coarse_nsecs(tk); + + timekeeping_update_from_shadow(tkd, clock_set); + + return !!clock_set; +} + +static bool timekeeping_advance(enum timekeeping_adv_mode mode) +{ + guard(raw_spinlock_irqsave)(&tk_core.lock); + return __timekeeping_advance(&tk_core, mode); } /** - * getboottime - Return the real time of system boot. - * @ts: pointer to the timespec to be set + * update_wall_time - Uses the current clocksource to increment the wall time + * + * It also updates the enabled auxiliary clock timekeepers + */ +void update_wall_time(void) +{ + if (timekeeping_advance(TK_ADV_TICK)) + clock_was_set_delayed(); + tk_aux_advance(); +} + +/** + * getboottime64 - Return the real time of system boot. + * @ts: pointer to the timespec64 to be set * - * Returns the wall-time of boot in a timespec. + * 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 getboottime(struct timespec *ts) +void getboottime64(struct timespec64 *ts) { - struct timekeeper *tk = &timekeeper; - struct timespec boottime = { - .tv_sec = tk->wall_to_monotonic.tv_sec + - tk->total_sleep_time.tv_sec, - .tv_nsec = tk->wall_to_monotonic.tv_nsec + - tk->total_sleep_time.tv_nsec - }; + struct timekeeper *tk = &tk_core.timekeeper; + ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot); - set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec); + *ts = ktime_to_timespec64(t); } -EXPORT_SYMBOL_GPL(getboottime); +EXPORT_SYMBOL_GPL(getboottime64); -/** - * get_monotonic_boottime - Returns monotonic time since boot - * @ts: pointer to the timespec to be set - * - * Returns the monotonic time since boot in a timespec. - * - * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also - * includes the time spent in suspend. - */ -void get_monotonic_boottime(struct timespec *ts) +void ktime_get_coarse_real_ts64(struct timespec64 *ts) { - struct timekeeper *tk = &timekeeper; - struct timespec tomono, sleep; - s64 nsec; + struct timekeeper *tk = &tk_core.timekeeper; unsigned int seq; - WARN_ON(timekeeping_suspended); - do { - seq = read_seqcount_begin(&timekeeper_seq); - ts->tv_sec = tk->xtime_sec; - nsec = timekeeping_get_ns(tk); - tomono = tk->wall_to_monotonic; - sleep = tk->total_sleep_time; - - } while (read_seqcount_retry(&timekeeper_seq, seq)); + seq = read_seqcount_begin(&tk_core.seq); - ts->tv_sec += tomono.tv_sec + sleep.tv_sec; - ts->tv_nsec = 0; - timespec_add_ns(ts, nsec + tomono.tv_nsec + sleep.tv_nsec); + *ts = tk_xtime_coarse(tk); + } while (read_seqcount_retry(&tk_core.seq, seq)); } -EXPORT_SYMBOL_GPL(get_monotonic_boottime); +EXPORT_SYMBOL(ktime_get_coarse_real_ts64); /** - * ktime_get_boottime - Returns monotonic time since boot in a ktime - * - * Returns the monotonic time since boot in a ktime + * ktime_get_coarse_real_ts64_mg - return latter of coarse grained time or floor + * @ts: timespec64 to be filled * - * This is similar to CLOCK_MONTONIC/ktime_get, but also - * includes the time spent in suspend. + * Fetch the global mg_floor value, convert it to realtime and compare it + * to the current coarse-grained time. Fill @ts with whichever is + * latest. Note that this is a filesystem-specific interface and should be + * avoided outside of that context. */ -ktime_t ktime_get_boottime(void) +void ktime_get_coarse_real_ts64_mg(struct timespec64 *ts) { - struct timespec ts; + struct timekeeper *tk = &tk_core.timekeeper; + u64 floor = atomic64_read(&mg_floor); + ktime_t f_real, offset, coarse; + unsigned int seq; - get_monotonic_boottime(&ts); - return timespec_to_ktime(ts); + do { + seq = read_seqcount_begin(&tk_core.seq); + *ts = tk_xtime_coarse(tk); + offset = tk_core.timekeeper.offs_real; + } while (read_seqcount_retry(&tk_core.seq, seq)); + + coarse = timespec64_to_ktime(*ts); + f_real = ktime_add(floor, offset); + if (ktime_after(f_real, coarse)) + *ts = ktime_to_timespec64(f_real); } -EXPORT_SYMBOL_GPL(ktime_get_boottime); /** - * monotonic_to_bootbased - Convert the monotonic time to boot based. - * @ts: pointer to the timespec to be converted + * ktime_get_real_ts64_mg - attempt to update floor value and return result + * @ts: pointer to the timespec to be set + * + * Get a monotonic fine-grained time value and attempt to swap it into + * mg_floor. If that succeeds then accept the new floor value. If it fails + * then another task raced in during the interim time and updated the + * floor. Since any update to the floor must be later than the previous + * floor, either outcome is acceptable. + * + * Typically this will be called after calling ktime_get_coarse_real_ts64_mg(), + * and determining that the resulting coarse-grained timestamp did not effect + * a change in ctime. Any more recent floor value would effect a change to + * ctime, so there is no need to retry the atomic64_try_cmpxchg() on failure. + * + * @ts will be filled with the latest floor value, regardless of the outcome of + * the cmpxchg. Note that this is a filesystem specific interface and should be + * avoided outside of that context. */ -void monotonic_to_bootbased(struct timespec *ts) -{ - struct timekeeper *tk = &timekeeper; - - *ts = timespec_add(*ts, tk->total_sleep_time); -} -EXPORT_SYMBOL_GPL(monotonic_to_bootbased); - -unsigned long get_seconds(void) +void ktime_get_real_ts64_mg(struct timespec64 *ts) { - struct timekeeper *tk = &timekeeper; - - return tk->xtime_sec; -} -EXPORT_SYMBOL(get_seconds); - -struct timespec __current_kernel_time(void) -{ - struct timekeeper *tk = &timekeeper; - - return tk_xtime(tk); -} - -struct timespec current_kernel_time(void) -{ - struct timekeeper *tk = &timekeeper; - struct timespec now; - unsigned long seq; + struct timekeeper *tk = &tk_core.timekeeper; + ktime_t old = atomic64_read(&mg_floor); + ktime_t offset, mono; + unsigned int seq; + u64 nsecs; do { - seq = read_seqcount_begin(&timekeeper_seq); + seq = read_seqcount_begin(&tk_core.seq); + + ts->tv_sec = tk->xtime_sec; + mono = tk->tkr_mono.base; + nsecs = timekeeping_get_ns(&tk->tkr_mono); + offset = tk_core.timekeeper.offs_real; + } while (read_seqcount_retry(&tk_core.seq, seq)); - now = tk_xtime(tk); - } while (read_seqcount_retry(&timekeeper_seq, seq)); + mono = ktime_add_ns(mono, nsecs); - return now; + /* + * Attempt to update the floor with the new time value. As any + * update must be later then the existing floor, and would effect + * a change to ctime from the perspective of the current task, + * accept the resulting floor value regardless of the outcome of + * the swap. + */ + if (atomic64_try_cmpxchg(&mg_floor, &old, mono)) { + ts->tv_nsec = 0; + timespec64_add_ns(ts, nsecs); + timekeeping_inc_mg_floor_swaps(); + } else { + /* + * Another task changed mg_floor since "old" was fetched. + * "old" has been updated with the latest value of "mg_floor". + * That value is newer than the previous floor value, which + * is enough to effect a change to ctime. Accept it. + */ + *ts = ktime_to_timespec64(ktime_add(old, offset)); + } } -EXPORT_SYMBOL(current_kernel_time); -struct timespec get_monotonic_coarse(void) +void ktime_get_coarse_ts64(struct timespec64 *ts) { - struct timekeeper *tk = &timekeeper; - struct timespec now, mono; - unsigned long seq; + struct timekeeper *tk = &tk_core.timekeeper; + struct timespec64 now, mono; + unsigned int seq; do { - seq = read_seqcount_begin(&timekeeper_seq); + seq = read_seqcount_begin(&tk_core.seq); - now = tk_xtime(tk); + now = tk_xtime_coarse(tk); mono = tk->wall_to_monotonic; - } while (read_seqcount_retry(&timekeeper_seq, seq)); + } while (read_seqcount_retry(&tk_core.seq, seq)); - set_normalized_timespec(&now, now.tv_sec + mono.tv_sec, - now.tv_nsec + mono.tv_nsec); - return now; + 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 @@ -1583,157 +2542,572 @@ struct timespec get_monotonic_coarse(void) void do_timer(unsigned long ticks) { jiffies_64 += ticks; - update_wall_time(); - calc_global_load(ticks); -} - -/** - * get_xtime_and_monotonic_and_sleep_offset() - get xtime, wall_to_monotonic, - * and sleep offsets. - * @xtim: pointer to timespec to be set with xtime - * @wtom: pointer to timespec to be set with wall_to_monotonic - * @sleep: pointer to timespec to be set with time in suspend - */ -void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim, - struct timespec *wtom, struct timespec *sleep) -{ - struct timekeeper *tk = &timekeeper; - unsigned long seq; - - do { - seq = read_seqcount_begin(&timekeeper_seq); - *xtim = tk_xtime(tk); - *wtom = tk->wall_to_monotonic; - *sleep = tk->total_sleep_time; - } while (read_seqcount_retry(&timekeeper_seq, seq)); + calc_global_load(); } -#ifdef CONFIG_HIGH_RES_TIMERS /** - * ktime_get_update_offsets - hrtimer helper + * 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. * - * Returns current monotonic time and updates the offsets - * Called from hrtimer_interupt() or retrigger_next_event() + * Called from hrtimer_interrupt() or retrigger_next_event() */ -ktime_t ktime_get_update_offsets(ktime_t *offs_real, ktime_t *offs_boot, - ktime_t *offs_tai) +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 = &timekeeper; - ktime_t now; + struct timekeeper *tk = &tk_core.timekeeper; unsigned int seq; - u64 secs, nsecs; + ktime_t base; + u64 nsecs; do { - seq = read_seqcount_begin(&timekeeper_seq); + seq = read_seqcount_begin(&tk_core.seq); - secs = tk->xtime_sec; - nsecs = timekeeping_get_ns(tk); + base = tk->tkr_mono.base; + nsecs = timekeeping_get_ns(&tk->tkr_mono); + base = ktime_add_ns(base, nsecs); - *offs_real = tk->offs_real; - *offs_boot = tk->offs_boot; - *offs_tai = tk->offs_tai; - } while (read_seqcount_retry(&timekeeper_seq, seq)); + 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; + } - now = ktime_add_ns(ktime_set(secs, 0), nsecs); - now = ktime_sub(now, *offs_real); - return now; + /* 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; } -#endif -/** - * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format +/* + * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex */ -ktime_t ktime_get_monotonic_offset(void) +static int timekeeping_validate_timex(const struct __kernel_timex *txc, bool aux_clock) { - struct timekeeper *tk = &timekeeper; - unsigned long seq; - struct timespec wtom; + 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; + } - do { - seq = read_seqcount_begin(&timekeeper_seq); - wtom = tk->wall_to_monotonic; - } while (read_seqcount_retry(&timekeeper_seq, seq)); + 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 positive 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; - return timespec_to_ktime(wtom); + 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; + } + + if (aux_clock) { + /* Auxiliary clocks are similar to TAI and do not have leap seconds */ + if (txc->status & (STA_INS | STA_DEL)) + return -EINVAL; + + /* No TAI offset setting */ + if (txc->modes & ADJ_TAI) + return -EINVAL; + + /* No PPS support either */ + if (txc->status & (STA_PPSFREQ | STA_PPSTIME)) + return -EINVAL; + } + + return 0; } -EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset); /** - * do_adjtimex() - Accessor function to NTP __do_adjtimex function + * random_get_entropy_fallback - Returns the raw clock source value, + * used by random.c for platforms with no valid random_get_entropy(). */ -int do_adjtimex(struct timex *txc) +unsigned long random_get_entropy_fallback(void) { - struct timekeeper *tk = &timekeeper; - unsigned long flags; - struct timespec ts; + 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); + +struct adjtimex_result { + struct audit_ntp_data ad; + struct timespec64 delta; + bool clock_set; +}; + +static int __do_adjtimex(struct tk_data *tkd, struct __kernel_timex *txc, + struct adjtimex_result *result) +{ + struct timekeeper *tks = &tkd->shadow_timekeeper; + bool aux_clock = !timekeeper_is_core_tk(tks); + struct timespec64 ts; s32 orig_tai, tai; int ret; /* Validate the data before disabling interrupts */ - ret = ntp_validate_timex(txc); + ret = timekeeping_validate_timex(txc, aux_clock); if (ret) return ret; + add_device_randomness(txc, sizeof(*txc)); + + if (!aux_clock) + ktime_get_real_ts64(&ts); + else + tk_get_aux_ts64(tkd->timekeeper.id, &ts); + + add_device_randomness(&ts, sizeof(ts)); + + guard(raw_spinlock_irqsave)(&tkd->lock); + + if (!tks->clock_valid) + return -ENODEV; if (txc->modes & ADJ_SETOFFSET) { - struct timespec delta; - delta.tv_sec = txc->time.tv_sec; - delta.tv_nsec = txc->time.tv_usec; + result->delta.tv_sec = txc->time.tv_sec; + result->delta.tv_nsec = txc->time.tv_usec; if (!(txc->modes & ADJ_NANO)) - delta.tv_nsec *= 1000; - ret = timekeeping_inject_offset(&delta); + result->delta.tv_nsec *= 1000; + ret = __timekeeping_inject_offset(tkd, &result->delta); if (ret) return ret; + result->clock_set = true; } - getnstimeofday(&ts); - - raw_spin_lock_irqsave(&timekeeper_lock, flags); - write_seqcount_begin(&timekeeper_seq); - - orig_tai = tai = tk->tai_offset; - ret = __do_adjtimex(txc, &ts, &tai); + orig_tai = tai = tks->tai_offset; + ret = ntp_adjtimex(tks->id, txc, &ts, &tai, &result->ad); if (tai != orig_tai) { - __timekeeping_set_tai_offset(tk, tai); - update_pvclock_gtod(tk, true); - clock_was_set_delayed(); + __timekeeping_set_tai_offset(tks, tai); + timekeeping_update_from_shadow(tkd, TK_CLOCK_WAS_SET); + result->clock_set = true; + } else { + tk_update_leap_state_all(&tk_core); } - write_seqcount_end(&timekeeper_seq); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); + + /* Update the multiplier immediately if frequency was set directly */ + if (txc->modes & (ADJ_FREQUENCY | ADJ_TICK)) + result->clock_set |= __timekeeping_advance(tkd, TK_ADV_FREQ); return ret; } +/** + * do_adjtimex() - Accessor function to NTP __do_adjtimex function + * @txc: Pointer to kernel_timex structure containing NTP parameters + */ +int do_adjtimex(struct __kernel_timex *txc) +{ + struct adjtimex_result result = { }; + int ret; + + ret = __do_adjtimex(&tk_core, txc, &result); + if (ret < 0) + return ret; + + if (txc->modes & ADJ_SETOFFSET) + audit_tk_injoffset(result.delta); + + audit_ntp_log(&result.ad); + + if (result.clock_set) + clock_was_set(CLOCK_SET_WALL); + + ntp_notify_cmos_timer(result.delta.tv_sec != 0); + + return ret; +} + +/* + * Invoked from NTP with the time keeper lock held, so lockless access is + * fine. + */ +long ktime_get_ntp_seconds(unsigned int id) +{ + return timekeeper_data[id].timekeeper.xtime_sec; +} + #ifdef CONFIG_NTP_PPS /** * hardpps() - Accessor function to NTP __hardpps function + * @phase_ts: Pointer to timespec64 structure representing phase timestamp + * @raw_ts: Pointer to timespec64 structure representing raw timestamp */ -void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts) +void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts) { - unsigned long flags; + guard(raw_spinlock_irqsave)(&tk_core.lock); + __hardpps(phase_ts, raw_ts); +} +EXPORT_SYMBOL(hardpps); +#endif /* CONFIG_NTP_PPS */ - raw_spin_lock_irqsave(&timekeeper_lock, flags); - write_seqcount_begin(&timekeeper_seq); +#ifdef CONFIG_POSIX_AUX_CLOCKS +#include "posix-timers.h" - __hardpps(phase_ts, raw_ts); +/* + * Bitmap for the activated auxiliary timekeepers to allow lockless quick + * checks in the hot paths without touching extra cache lines. If set, then + * the state of the corresponding timekeeper has to be re-checked under + * timekeeper::lock. + */ +static unsigned long aux_timekeepers; - write_seqcount_end(&timekeeper_seq); - raw_spin_unlock_irqrestore(&timekeeper_lock, flags); +static inline unsigned int clockid_to_tkid(unsigned int id) +{ + return TIMEKEEPER_AUX_FIRST + id - CLOCK_AUX; +} + +static inline struct tk_data *aux_get_tk_data(clockid_t id) +{ + if (!clockid_aux_valid(id)) + return NULL; + return &timekeeper_data[clockid_to_tkid(id)]; +} + +/* Invoked from timekeeping after a clocksource change */ +static void tk_aux_update_clocksource(void) +{ + unsigned long active = READ_ONCE(aux_timekeepers); + unsigned int id; + + for_each_set_bit(id, &active, BITS_PER_LONG) { + struct tk_data *tkd = &timekeeper_data[id + TIMEKEEPER_AUX_FIRST]; + struct timekeeper *tks = &tkd->shadow_timekeeper; + + guard(raw_spinlock_irqsave)(&tkd->lock); + if (!tks->clock_valid) + continue; + + timekeeping_forward_now(tks); + tk_setup_internals(tks, tk_core.timekeeper.tkr_mono.clock); + timekeeping_update_from_shadow(tkd, TK_UPDATE_ALL); + } +} + +static void tk_aux_advance(void) +{ + unsigned long active = READ_ONCE(aux_timekeepers); + unsigned int id; + + /* Lockless quick check to avoid extra cache lines */ + for_each_set_bit(id, &active, BITS_PER_LONG) { + struct tk_data *aux_tkd = &timekeeper_data[id + TIMEKEEPER_AUX_FIRST]; + + guard(raw_spinlock)(&aux_tkd->lock); + if (aux_tkd->shadow_timekeeper.clock_valid) + __timekeeping_advance(aux_tkd, TK_ADV_TICK); + } } -EXPORT_SYMBOL(hardpps); -#endif /** - * xtime_update() - advances the timekeeping infrastructure - * @ticks: number of ticks, that have elapsed since the last call. + * ktime_get_aux - Get time for a AUX clock + * @id: ID of the clock to read (CLOCK_AUX...) + * @kt: Pointer to ktime_t to store the time stamp * - * Must be called with interrupts disabled. + * Returns: True if the timestamp is valid, false otherwise */ -void xtime_update(unsigned long ticks) +bool ktime_get_aux(clockid_t id, ktime_t *kt) +{ + struct tk_data *aux_tkd = aux_get_tk_data(id); + struct timekeeper *aux_tk; + unsigned int seq; + ktime_t base; + u64 nsecs; + + WARN_ON(timekeeping_suspended); + + if (!aux_tkd) + return false; + + aux_tk = &aux_tkd->timekeeper; + do { + seq = read_seqcount_begin(&aux_tkd->seq); + if (!aux_tk->clock_valid) + return false; + + base = ktime_add(aux_tk->tkr_mono.base, aux_tk->offs_aux); + nsecs = timekeeping_get_ns(&aux_tk->tkr_mono); + } while (read_seqcount_retry(&aux_tkd->seq, seq)); + + *kt = ktime_add_ns(base, nsecs); + return true; +} +EXPORT_SYMBOL_GPL(ktime_get_aux); + +/** + * ktime_get_aux_ts64 - Get time for a AUX clock + * @id: ID of the clock to read (CLOCK_AUX...) + * @ts: Pointer to timespec64 to store the time stamp + * + * Returns: True if the timestamp is valid, false otherwise + */ +bool ktime_get_aux_ts64(clockid_t id, struct timespec64 *ts) +{ + ktime_t now; + + if (!ktime_get_aux(id, &now)) + return false; + *ts = ktime_to_timespec64(now); + return true; +} +EXPORT_SYMBOL_GPL(ktime_get_aux_ts64); + +static int aux_get_res(clockid_t id, struct timespec64 *tp) +{ + if (!clockid_aux_valid(id)) + return -ENODEV; + + tp->tv_sec = aux_clock_resolution_ns() / NSEC_PER_SEC; + tp->tv_nsec = aux_clock_resolution_ns() % NSEC_PER_SEC; + return 0; +} + +static int aux_get_timespec(clockid_t id, struct timespec64 *tp) +{ + return ktime_get_aux_ts64(id, tp) ? 0 : -ENODEV; +} + +static int aux_clock_set(const clockid_t id, const struct timespec64 *tnew) +{ + struct tk_data *aux_tkd = aux_get_tk_data(id); + struct timekeeper *aux_tks; + ktime_t tnow, nsecs; + + if (!timespec64_valid_settod(tnew)) + return -EINVAL; + if (!aux_tkd) + return -ENODEV; + + aux_tks = &aux_tkd->shadow_timekeeper; + + guard(raw_spinlock_irq)(&aux_tkd->lock); + if (!aux_tks->clock_valid) + return -ENODEV; + + /* Forward the timekeeper base time */ + timekeeping_forward_now(aux_tks); + /* + * Get the updated base time. tkr_mono.base has not been + * updated yet, so do that first. That makes the update + * in timekeeping_update_from_shadow() redundant, but + * that's harmless. After that @tnow can be calculated + * by using tkr_mono::cycle_last, which has been set + * by timekeeping_forward_now(). + */ + tk_update_ktime_data(aux_tks); + nsecs = timekeeping_cycles_to_ns(&aux_tks->tkr_mono, aux_tks->tkr_mono.cycle_last); + tnow = ktime_add(aux_tks->tkr_mono.base, nsecs); + + /* + * Calculate the new AUX offset as delta to @tnow ("monotonic"). + * That avoids all the tk::xtime back and forth conversions as + * xtime ("realtime") is not applicable for auxiliary clocks and + * kept in sync with "monotonic". + */ + tk_update_aux_offs(aux_tks, ktime_sub(timespec64_to_ktime(*tnew), tnow)); + + timekeeping_update_from_shadow(aux_tkd, TK_UPDATE_ALL); + return 0; +} + +static int aux_clock_adj(const clockid_t id, struct __kernel_timex *txc) +{ + struct tk_data *aux_tkd = aux_get_tk_data(id); + struct adjtimex_result result = { }; + + if (!aux_tkd) + return -ENODEV; + + /* + * @result is ignored for now as there are neither hrtimers nor a + * RTC related to auxiliary clocks for now. + */ + return __do_adjtimex(aux_tkd, txc, &result); +} + +const struct k_clock clock_aux = { + .clock_getres = aux_get_res, + .clock_get_timespec = aux_get_timespec, + .clock_set = aux_clock_set, + .clock_adj = aux_clock_adj, +}; + +static void aux_clock_enable(clockid_t id) +{ + struct tk_read_base *tkr_raw = &tk_core.timekeeper.tkr_raw; + struct tk_data *aux_tkd = aux_get_tk_data(id); + struct timekeeper *aux_tks = &aux_tkd->shadow_timekeeper; + + /* Prevent the core timekeeper from changing. */ + guard(raw_spinlock_irq)(&tk_core.lock); + + /* + * Setup the auxiliary clock assuming that the raw core timekeeper + * clock frequency conversion is close enough. Userspace has to + * adjust for the deviation via clock_adjtime(2). + */ + guard(raw_spinlock_nested)(&aux_tkd->lock); + + /* Remove leftovers of a previous registration */ + memset(aux_tks, 0, sizeof(*aux_tks)); + /* Restore the timekeeper id */ + aux_tks->id = aux_tkd->timekeeper.id; + /* Setup the timekeeper based on the current system clocksource */ + tk_setup_internals(aux_tks, tkr_raw->clock); + + /* Mark it valid and set it live */ + aux_tks->clock_valid = true; + timekeeping_update_from_shadow(aux_tkd, TK_UPDATE_ALL); +} + +static void aux_clock_disable(clockid_t id) +{ + struct tk_data *aux_tkd = aux_get_tk_data(id); + + guard(raw_spinlock_irq)(&aux_tkd->lock); + aux_tkd->shadow_timekeeper.clock_valid = false; + timekeeping_update_from_shadow(aux_tkd, TK_UPDATE_ALL); +} + +static DEFINE_MUTEX(aux_clock_mutex); + +static ssize_t aux_clock_enable_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t count) +{ + /* Lazy atoi() as name is "0..7" */ + int id = kobj->name[0] & 0x7; + bool enable; + + if (!capable(CAP_SYS_TIME)) + return -EPERM; + + if (kstrtobool(buf, &enable) < 0) + return -EINVAL; + + guard(mutex)(&aux_clock_mutex); + if (enable == test_bit(id, &aux_timekeepers)) + return count; + + if (enable) { + aux_clock_enable(CLOCK_AUX + id); + set_bit(id, &aux_timekeepers); + } else { + aux_clock_disable(CLOCK_AUX + id); + clear_bit(id, &aux_timekeepers); + } + return count; +} + +static ssize_t aux_clock_enable_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) +{ + unsigned long active = READ_ONCE(aux_timekeepers); + /* Lazy atoi() as name is "0..7" */ + int id = kobj->name[0] & 0x7; + + return sysfs_emit(buf, "%d\n", test_bit(id, &active)); +} + +static struct kobj_attribute aux_clock_enable_attr = __ATTR_RW(aux_clock_enable); + +static struct attribute *aux_clock_enable_attrs[] = { + &aux_clock_enable_attr.attr, + NULL +}; + +static const struct attribute_group aux_clock_enable_attr_group = { + .attrs = aux_clock_enable_attrs, +}; + +static int __init tk_aux_sysfs_init(void) +{ + struct kobject *auxo, *tko = kobject_create_and_add("time", kernel_kobj); + int ret = -ENOMEM; + + if (!tko) + return ret; + + auxo = kobject_create_and_add("aux_clocks", tko); + if (!auxo) + goto err_clean; + + for (int i = 0; i < MAX_AUX_CLOCKS; i++) { + char id[2] = { [0] = '0' + i, }; + struct kobject *clk = kobject_create_and_add(id, auxo); + + if (!clk) { + ret = -ENOMEM; + goto err_clean; + } + + ret = sysfs_create_group(clk, &aux_clock_enable_attr_group); + if (ret) + goto err_clean; + } + return 0; + +err_clean: + kobject_put(auxo); + kobject_put(tko); + return ret; +} +late_initcall(tk_aux_sysfs_init); + +static __init void tk_aux_setup(void) { - write_seqlock(&jiffies_lock); - do_timer(ticks); - write_sequnlock(&jiffies_lock); + for (int i = TIMEKEEPER_AUX_FIRST; i <= TIMEKEEPER_AUX_LAST; i++) + tkd_basic_setup(&timekeeper_data[i], i, false); } +#endif /* CONFIG_POSIX_AUX_CLOCKS */ |