| /* |
| * linux/kernel/time/timekeeping.c |
| * |
| * Kernel timekeeping code and accessor functions |
| * |
| * This code was moved from linux/kernel/timer.c. |
| * Please see that file for copyright and history logs. |
| * |
| */ |
| |
| #include <linux/timekeeper_internal.h> |
| #include <linux/module.h> |
| #include <linux/interrupt.h> |
| #include <linux/percpu.h> |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/sched.h> |
| #include <linux/sched/loadavg.h> |
| #include <linux/syscore_ops.h> |
| #include <linux/clocksource.h> |
| #include <linux/jiffies.h> |
| #include <linux/time.h> |
| #include <linux/tick.h> |
| #include <linux/stop_machine.h> |
| #include <linux/pvclock_gtod.h> |
| #include <linux/compiler.h> |
| |
| #include "tick-internal.h" |
| #include "ntp_internal.h" |
| #include "timekeeping_internal.h" |
| |
| #define TK_CLEAR_NTP (1 << 0) |
| #define TK_MIRROR (1 << 1) |
| #define TK_CLOCK_WAS_SET (1 << 2) |
| |
| /* |
| * The most important data for readout fits into a single 64 byte |
| * cache line. |
| */ |
| static struct { |
| seqcount_t seq; |
| struct timekeeper timekeeper; |
| } tk_core ____cacheline_aligned; |
| |
| static DEFINE_RAW_SPINLOCK(timekeeper_lock); |
| static struct timekeeper shadow_timekeeper; |
| |
| /** |
| * struct tk_fast - NMI safe timekeeper |
| * @seq: Sequence counter for protecting updates. The lowest bit |
| * is the index for the tk_read_base array |
| * @base: tk_read_base array. Access is indexed by the lowest bit of |
| * @seq. |
| * |
| * See @update_fast_timekeeper() below. |
| */ |
| struct tk_fast { |
| seqcount_t seq; |
| struct tk_read_base base[2]; |
| }; |
| |
| static struct tk_fast tk_fast_mono ____cacheline_aligned; |
| static struct tk_fast tk_fast_raw ____cacheline_aligned; |
| |
| /* flag for if timekeeping is suspended */ |
| int __read_mostly timekeeping_suspended; |
| |
| static inline void tk_normalize_xtime(struct timekeeper *tk) |
| { |
| while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) { |
| tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift; |
| tk->xtime_sec++; |
| } |
| } |
| |
| static inline struct timespec64 tk_xtime(struct timekeeper *tk) |
| { |
| struct timespec64 ts; |
| |
| ts.tv_sec = tk->xtime_sec; |
| ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift); |
| return ts; |
| } |
| |
| static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts) |
| { |
| tk->xtime_sec = ts->tv_sec; |
| tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift; |
| } |
| |
| static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts) |
| { |
| tk->xtime_sec += ts->tv_sec; |
| tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift; |
| tk_normalize_xtime(tk); |
| } |
| |
| static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm) |
| { |
| struct timespec64 tmp; |
| |
| /* |
| * Verify consistency of: offset_real = -wall_to_monotonic |
| * before modifying anything |
| */ |
| set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec, |
| -tk->wall_to_monotonic.tv_nsec); |
| WARN_ON_ONCE(tk->offs_real != timespec64_to_ktime(tmp)); |
| tk->wall_to_monotonic = wtm; |
| set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec); |
| tk->offs_real = timespec64_to_ktime(tmp); |
| tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0)); |
| } |
| |
| static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta) |
| { |
| tk->offs_boot = ktime_add(tk->offs_boot, delta); |
| } |
| |
| #ifdef CONFIG_DEBUG_TIMEKEEPING |
| #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */ |
| |
| static void timekeeping_check_update(struct timekeeper *tk, u64 offset) |
| { |
| |
| u64 max_cycles = tk->tkr_mono.clock->max_cycles; |
| const char *name = tk->tkr_mono.clock->name; |
| |
| if (offset > max_cycles) { |
| printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n", |
| offset, name, max_cycles); |
| printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n"); |
| } else { |
| if (offset > (max_cycles >> 1)) { |
| printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n", |
| offset, name, max_cycles >> 1); |
| printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n"); |
| } |
| } |
| |
| if (tk->underflow_seen) { |
| if (jiffies - tk->last_warning > WARNING_FREQ) { |
| printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name); |
| printk_deferred(" Please report this, consider using a different clocksource, if possible.\n"); |
| printk_deferred(" Your kernel is probably still fine.\n"); |
| tk->last_warning = jiffies; |
| } |
| tk->underflow_seen = 0; |
| } |
| |
| if (tk->overflow_seen) { |
| if (jiffies - tk->last_warning > WARNING_FREQ) { |
| printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name); |
| printk_deferred(" Please report this, consider using a different clocksource, if possible.\n"); |
| printk_deferred(" Your kernel is probably still fine.\n"); |
| tk->last_warning = jiffies; |
| } |
| tk->overflow_seen = 0; |
| } |
| } |
| |
| static inline u64 timekeeping_get_delta(struct tk_read_base *tkr) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| u64 now, last, mask, max, delta; |
| unsigned int seq; |
| |
| /* |
| * Since we're called holding a seqlock, the data may shift |
| * under us while we're doing the calculation. This can cause |
| * false positives, since we'd note a problem but throw the |
| * results away. So nest another seqlock here to atomically |
| * grab the points we are checking with. |
| */ |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| now = tkr->read(tkr->clock); |
| last = tkr->cycle_last; |
| mask = tkr->mask; |
| max = tkr->clock->max_cycles; |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| delta = clocksource_delta(now, last, mask); |
| |
| /* |
| * Try to catch underflows by checking if we are seeing small |
| * mask-relative negative values. |
| */ |
| if (unlikely((~delta & mask) < (mask >> 3))) { |
| tk->underflow_seen = 1; |
| delta = 0; |
| } |
| |
| /* Cap delta value to the max_cycles values to avoid mult overflows */ |
| if (unlikely(delta > max)) { |
| tk->overflow_seen = 1; |
| delta = tkr->clock->max_cycles; |
| } |
| |
| return delta; |
| } |
| #else |
| static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset) |
| { |
| } |
| static inline u64 timekeeping_get_delta(struct tk_read_base *tkr) |
| { |
| u64 cycle_now, delta; |
| |
| /* read clocksource */ |
| cycle_now = tkr->read(tkr->clock); |
| |
| /* calculate the delta since the last update_wall_time */ |
| delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask); |
| |
| return delta; |
| } |
| #endif |
| |
| /** |
| * tk_setup_internals - Set up internals to use clocksource clock. |
| * |
| * @tk: The target timekeeper to setup. |
| * @clock: Pointer to clocksource. |
| * |
| * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment |
| * pair and interval request. |
| * |
| * Unless you're the timekeeping code, you should not be using this! |
| */ |
| static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock) |
| { |
| u64 interval; |
| u64 tmp, ntpinterval; |
| struct clocksource *old_clock; |
| |
| ++tk->cs_was_changed_seq; |
| old_clock = tk->tkr_mono.clock; |
| tk->tkr_mono.clock = clock; |
| tk->tkr_mono.read = clock->read; |
| tk->tkr_mono.mask = clock->mask; |
| tk->tkr_mono.cycle_last = tk->tkr_mono.read(clock); |
| |
| tk->tkr_raw.clock = clock; |
| tk->tkr_raw.read = clock->read; |
| tk->tkr_raw.mask = clock->mask; |
| tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last; |
| |
| /* Do the ns -> cycle conversion first, using original mult */ |
| tmp = NTP_INTERVAL_LENGTH; |
| tmp <<= clock->shift; |
| ntpinterval = tmp; |
| tmp += clock->mult/2; |
| do_div(tmp, clock->mult); |
| if (tmp == 0) |
| tmp = 1; |
| |
| interval = (u64) tmp; |
| tk->cycle_interval = interval; |
| |
| /* Go back from cycles -> shifted ns */ |
| tk->xtime_interval = interval * clock->mult; |
| tk->xtime_remainder = ntpinterval - tk->xtime_interval; |
| tk->raw_interval = (interval * clock->mult) >> clock->shift; |
| |
| /* if changing clocks, convert xtime_nsec shift units */ |
| if (old_clock) { |
| int shift_change = clock->shift - old_clock->shift; |
| if (shift_change < 0) |
| tk->tkr_mono.xtime_nsec >>= -shift_change; |
| else |
| tk->tkr_mono.xtime_nsec <<= shift_change; |
| } |
| tk->tkr_raw.xtime_nsec = 0; |
| |
| tk->tkr_mono.shift = clock->shift; |
| tk->tkr_raw.shift = clock->shift; |
| |
| tk->ntp_error = 0; |
| tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; |
| tk->ntp_tick = ntpinterval << tk->ntp_error_shift; |
| |
| /* |
| * The timekeeper keeps its own mult values for the currently |
| * active clocksource. These value will be adjusted via NTP |
| * to counteract clock drifting. |
| */ |
| tk->tkr_mono.mult = clock->mult; |
| tk->tkr_raw.mult = clock->mult; |
| tk->ntp_err_mult = 0; |
| } |
| |
| /* Timekeeper helper functions. */ |
| |
| #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET |
| static u32 default_arch_gettimeoffset(void) { return 0; } |
| u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset; |
| #else |
| static inline u32 arch_gettimeoffset(void) { return 0; } |
| #endif |
| |
| static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr, u64 delta) |
| { |
| u64 nsec; |
| |
| nsec = delta * tkr->mult + tkr->xtime_nsec; |
| nsec >>= tkr->shift; |
| |
| /* If arch requires, add in get_arch_timeoffset() */ |
| return nsec + arch_gettimeoffset(); |
| } |
| |
| static inline u64 timekeeping_get_ns(struct tk_read_base *tkr) |
| { |
| u64 delta; |
| |
| delta = timekeeping_get_delta(tkr); |
| return timekeeping_delta_to_ns(tkr, delta); |
| } |
| |
| static inline u64 timekeeping_cycles_to_ns(struct tk_read_base *tkr, u64 cycles) |
| { |
| u64 delta; |
| |
| /* calculate the delta since the last update_wall_time */ |
| delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask); |
| return timekeeping_delta_to_ns(tkr, delta); |
| } |
| |
| /** |
| * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper. |
| * @tkr: Timekeeping readout base from which we take the update |
| * |
| * We want to use this from any context including NMI and tracing / |
| * instrumenting the timekeeping code itself. |
| * |
| * Employ the latch technique; see @raw_write_seqcount_latch. |
| * |
| * So if a NMI hits the update of base[0] then it will use base[1] |
| * which is still consistent. In the worst case this can result is a |
| * slightly wrong timestamp (a few nanoseconds). See |
| * @ktime_get_mono_fast_ns. |
| */ |
| static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf) |
| { |
| struct tk_read_base *base = tkf->base; |
| |
| /* Force readers off to base[1] */ |
| raw_write_seqcount_latch(&tkf->seq); |
| |
| /* Update base[0] */ |
| memcpy(base, tkr, sizeof(*base)); |
| |
| /* Force readers back to base[0] */ |
| raw_write_seqcount_latch(&tkf->seq); |
| |
| /* Update base[1] */ |
| memcpy(base + 1, base, sizeof(*base)); |
| } |
| |
| /** |
| * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic |
| * |
| * This timestamp is not guaranteed to be monotonic across an update. |
| * The timestamp is calculated by: |
| * |
| * now = base_mono + clock_delta * slope |
| * |
| * So if the update lowers the slope, readers who are forced to the |
| * not yet updated second array are still using the old steeper slope. |
| * |
| * tmono |
| * ^ |
| * | o n |
| * | o n |
| * | u |
| * | o |
| * |o |
| * |12345678---> reader order |
| * |
| * o = old slope |
| * u = update |
| * n = new slope |
| * |
| * So reader 6 will observe time going backwards versus reader 5. |
| * |
| * While other CPUs are likely to be able observe that, the only way |
| * for a CPU local observation is when an NMI hits in the middle of |
| * the update. Timestamps taken from that NMI context might be ahead |
| * of the following timestamps. Callers need to be aware of that and |
| * deal with it. |
| */ |
| static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf) |
| { |
| struct tk_read_base *tkr; |
| unsigned int seq; |
| u64 now; |
| |
| do { |
| seq = raw_read_seqcount_latch(&tkf->seq); |
| tkr = tkf->base + (seq & 0x01); |
| now = ktime_to_ns(tkr->base); |
| |
| now += timekeeping_delta_to_ns(tkr, |
| clocksource_delta( |
| tkr->read(tkr->clock), |
| tkr->cycle_last, |
| tkr->mask)); |
| } while (read_seqcount_retry(&tkf->seq, seq)); |
| |
| return now; |
| } |
| |
| u64 ktime_get_mono_fast_ns(void) |
| { |
| return __ktime_get_fast_ns(&tk_fast_mono); |
| } |
| EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns); |
| |
| u64 ktime_get_raw_fast_ns(void) |
| { |
| return __ktime_get_fast_ns(&tk_fast_raw); |
| } |
| EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns); |
| |
| /** |
| * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock. |
| * |
| * To keep it NMI safe since we're accessing from tracing, we're not using a |
| * separate timekeeper with updates to monotonic clock and boot offset |
| * protected with seqlocks. This has the following minor side effects: |
| * |
| * (1) Its possible that a timestamp be taken after the boot offset is updated |
| * but before the timekeeper is updated. If this happens, the new boot offset |
| * is added to the old timekeeping making the clock appear to update slightly |
| * earlier: |
| * CPU 0 CPU 1 |
| * timekeeping_inject_sleeptime64() |
| * __timekeeping_inject_sleeptime(tk, delta); |
| * timestamp(); |
| * timekeeping_update(tk, TK_CLEAR_NTP...); |
| * |
| * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be |
| * partially updated. Since the tk->offs_boot update is a rare event, this |
| * should be a rare occurrence which postprocessing should be able to handle. |
| */ |
| u64 notrace ktime_get_boot_fast_ns(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| |
| return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot)); |
| } |
| EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns); |
| |
| /* Suspend-time cycles value for halted fast timekeeper. */ |
| static u64 cycles_at_suspend; |
| |
| static u64 dummy_clock_read(struct clocksource *cs) |
| { |
| return cycles_at_suspend; |
| } |
| |
| /** |
| * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource. |
| * @tk: Timekeeper to snapshot. |
| * |
| * It generally is unsafe to access the clocksource after timekeeping has been |
| * suspended, so take a snapshot of the readout base of @tk and use it as the |
| * fast timekeeper's readout base while suspended. It will return the same |
| * number of cycles every time until timekeeping is resumed at which time the |
| * proper readout base for the fast timekeeper will be restored automatically. |
| */ |
| static void halt_fast_timekeeper(struct timekeeper *tk) |
| { |
| static struct tk_read_base tkr_dummy; |
| struct tk_read_base *tkr = &tk->tkr_mono; |
| |
| memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy)); |
| cycles_at_suspend = tkr->read(tkr->clock); |
| tkr_dummy.read = dummy_clock_read; |
| update_fast_timekeeper(&tkr_dummy, &tk_fast_mono); |
| |
| tkr = &tk->tkr_raw; |
| memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy)); |
| tkr_dummy.read = dummy_clock_read; |
| update_fast_timekeeper(&tkr_dummy, &tk_fast_raw); |
| } |
| |
| #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD |
| |
| static inline void update_vsyscall(struct timekeeper *tk) |
| { |
| struct timespec xt, wm; |
| |
| xt = timespec64_to_timespec(tk_xtime(tk)); |
| wm = timespec64_to_timespec(tk->wall_to_monotonic); |
| update_vsyscall_old(&xt, &wm, tk->tkr_mono.clock, tk->tkr_mono.mult, |
| tk->tkr_mono.cycle_last); |
| } |
| |
| 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->tkr_mono.xtime_nsec & ((1ULL << tk->tkr_mono.shift) - 1); |
| if (remainder != 0) { |
| tk->tkr_mono.xtime_nsec -= remainder; |
| tk->tkr_mono.xtime_nsec += 1ULL << tk->tkr_mono.shift; |
| tk->ntp_error += remainder << tk->ntp_error_shift; |
| tk->ntp_error -= (1ULL << tk->tkr_mono.shift) << tk->ntp_error_shift; |
| } |
| } |
| #else |
| #define old_vsyscall_fixup(tk) |
| #endif |
| |
| static RAW_NOTIFIER_HEAD(pvclock_gtod_chain); |
| |
| static void update_pvclock_gtod(struct timekeeper *tk, bool was_set) |
| { |
| raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk); |
| } |
| |
| /** |
| * pvclock_gtod_register_notifier - register a pvclock timedata update listener |
| */ |
| int pvclock_gtod_register_notifier(struct notifier_block *nb) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long flags; |
| int ret; |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb); |
| update_pvclock_gtod(tk, true); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier); |
| |
| /** |
| * pvclock_gtod_unregister_notifier - unregister a pvclock |
| * timedata update listener |
| */ |
| int pvclock_gtod_unregister_notifier(struct notifier_block *nb) |
| { |
| unsigned long flags; |
| int ret; |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier); |
| |
| /* |
| * tk_update_leap_state - helper to update the next_leap_ktime |
| */ |
| static inline void tk_update_leap_state(struct timekeeper *tk) |
| { |
| tk->next_leap_ktime = ntp_get_next_leap(); |
| if (tk->next_leap_ktime != KTIME_MAX) |
| /* Convert to monotonic time */ |
| tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real); |
| } |
| |
| /* |
| * Update the ktime_t based scalar nsec members of the timekeeper |
| */ |
| static inline void tk_update_ktime_data(struct timekeeper *tk) |
| { |
| u64 seconds; |
| u32 nsec; |
| |
| /* |
| * The xtime based monotonic readout is: |
| * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now(); |
| * The ktime based monotonic readout is: |
| * nsec = base_mono + now(); |
| * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec |
| */ |
| seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec); |
| nsec = (u32) tk->wall_to_monotonic.tv_nsec; |
| tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec); |
| |
| /* Update the monotonic raw base */ |
| tk->tkr_raw.base = timespec64_to_ktime(tk->raw_time); |
| |
| /* |
| * The sum of the nanoseconds portions of xtime and |
| * wall_to_monotonic can be greater/equal one second. Take |
| * this into account before updating tk->ktime_sec. |
| */ |
| nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift); |
| if (nsec >= NSEC_PER_SEC) |
| seconds++; |
| tk->ktime_sec = seconds; |
| } |
| |
| /* must hold timekeeper_lock */ |
| static void timekeeping_update(struct timekeeper *tk, unsigned int action) |
| { |
| if (action & TK_CLEAR_NTP) { |
| tk->ntp_error = 0; |
| ntp_clear(); |
| } |
| |
| tk_update_leap_state(tk); |
| tk_update_ktime_data(tk); |
| |
| update_vsyscall(tk); |
| update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET); |
| |
| update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono); |
| update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw); |
| |
| if (action & TK_CLOCK_WAS_SET) |
| tk->clock_was_set_seq++; |
| /* |
| * The mirroring of the data to the shadow-timekeeper needs |
| * to happen last here to ensure we don't over-write the |
| * timekeeper structure on the next update with stale data |
| */ |
| if (action & TK_MIRROR) |
| memcpy(&shadow_timekeeper, &tk_core.timekeeper, |
| sizeof(tk_core.timekeeper)); |
| } |
| |
| /** |
| * timekeeping_forward_now - update clock to the current time |
| * |
| * Forward the current clock to update its state since the last call to |
| * update_wall_time(). This is useful before significant clock changes, |
| * as it avoids having to deal with this time offset explicitly. |
| */ |
| static void timekeeping_forward_now(struct timekeeper *tk) |
| { |
| struct clocksource *clock = tk->tkr_mono.clock; |
| u64 cycle_now, delta; |
| u64 nsec; |
| |
| cycle_now = tk->tkr_mono.read(clock); |
| delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask); |
| tk->tkr_mono.cycle_last = cycle_now; |
| tk->tkr_raw.cycle_last = cycle_now; |
| |
| tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult; |
| |
| /* If arch requires, add in get_arch_timeoffset() */ |
| tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift; |
| |
| tk_normalize_xtime(tk); |
| |
| nsec = clocksource_cyc2ns(delta, tk->tkr_raw.mult, tk->tkr_raw.shift); |
| timespec64_add_ns(&tk->raw_time, nsec); |
| } |
| |
| /** |
| * __getnstimeofday64 - Returns the time of day in a timespec64. |
| * @ts: pointer to the timespec to be set |
| * |
| * Updates the time of day in the timespec. |
| * Returns 0 on success, or -ve when suspended (timespec will be undefined). |
| */ |
| int __getnstimeofday64(struct timespec64 *ts) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long seq; |
| u64 nsecs; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| |
| ts->tv_sec = tk->xtime_sec; |
| nsecs = timekeeping_get_ns(&tk->tkr_mono); |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| ts->tv_nsec = 0; |
| timespec64_add_ns(ts, nsecs); |
| |
| /* |
| * Do not bail out early, in case there were callers still using |
| * the value, even in the face of the WARN_ON. |
| */ |
| if (unlikely(timekeeping_suspended)) |
| return -EAGAIN; |
| return 0; |
| } |
| EXPORT_SYMBOL(__getnstimeofday64); |
| |
| /** |
| * getnstimeofday64 - Returns the time of day in a timespec64. |
| * @ts: pointer to the timespec64 to be set |
| * |
| * Returns the time of day in a timespec64 (WARN if suspended). |
| */ |
| void getnstimeofday64(struct timespec64 *ts) |
| { |
| WARN_ON(__getnstimeofday64(ts)); |
| } |
| EXPORT_SYMBOL(getnstimeofday64); |
| |
| ktime_t ktime_get(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned int seq; |
| ktime_t base; |
| u64 nsecs; |
| |
| WARN_ON(timekeeping_suspended); |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| base = tk->tkr_mono.base; |
| nsecs = timekeeping_get_ns(&tk->tkr_mono); |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return ktime_add_ns(base, nsecs); |
| } |
| EXPORT_SYMBOL_GPL(ktime_get); |
| |
| u32 ktime_get_resolution_ns(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned int seq; |
| u32 nsecs; |
| |
| WARN_ON(timekeeping_suspended); |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift; |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return nsecs; |
| } |
| EXPORT_SYMBOL_GPL(ktime_get_resolution_ns); |
| |
| static ktime_t *offsets[TK_OFFS_MAX] = { |
| [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real, |
| [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot, |
| [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai, |
| }; |
| |
| ktime_t ktime_get_with_offset(enum tk_offsets offs) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned int seq; |
| ktime_t base, *offset = offsets[offs]; |
| u64 nsecs; |
| |
| WARN_ON(timekeeping_suspended); |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| base = ktime_add(tk->tkr_mono.base, *offset); |
| nsecs = timekeeping_get_ns(&tk->tkr_mono); |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return ktime_add_ns(base, nsecs); |
| |
| } |
| EXPORT_SYMBOL_GPL(ktime_get_with_offset); |
| |
| /** |
| * ktime_mono_to_any() - convert mononotic time to any other time |
| * @tmono: time to convert. |
| * @offs: which offset to use |
| */ |
| ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs) |
| { |
| ktime_t *offset = offsets[offs]; |
| unsigned long seq; |
| ktime_t tconv; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| tconv = ktime_add(tmono, *offset); |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return tconv; |
| } |
| EXPORT_SYMBOL_GPL(ktime_mono_to_any); |
| |
| /** |
| * ktime_get_raw - Returns the raw monotonic time in ktime_t format |
| */ |
| ktime_t ktime_get_raw(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned int seq; |
| ktime_t base; |
| u64 nsecs; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| base = tk->tkr_raw.base; |
| nsecs = timekeeping_get_ns(&tk->tkr_raw); |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return ktime_add_ns(base, nsecs); |
| } |
| EXPORT_SYMBOL_GPL(ktime_get_raw); |
| |
| /** |
| * ktime_get_ts64 - get the monotonic clock in timespec64 format |
| * @ts: pointer to timespec variable |
| * |
| * The function calculates the monotonic clock from the realtime |
| * clock and the wall_to_monotonic offset and stores the result |
| * in normalized timespec64 format in the variable pointed to by @ts. |
| */ |
| void ktime_get_ts64(struct timespec64 *ts) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct timespec64 tomono; |
| unsigned int seq; |
| u64 nsec; |
| |
| WARN_ON(timekeeping_suspended); |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| ts->tv_sec = tk->xtime_sec; |
| nsec = timekeeping_get_ns(&tk->tkr_mono); |
| tomono = tk->wall_to_monotonic; |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| ts->tv_sec += tomono.tv_sec; |
| ts->tv_nsec = 0; |
| timespec64_add_ns(ts, nsec + tomono.tv_nsec); |
| } |
| EXPORT_SYMBOL_GPL(ktime_get_ts64); |
| |
| /** |
| * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC |
| * |
| * Returns the seconds portion of CLOCK_MONOTONIC with a single non |
| * serialized read. tk->ktime_sec is of type 'unsigned long' so this |
| * works on both 32 and 64 bit systems. On 32 bit systems the readout |
| * covers ~136 years of uptime which should be enough to prevent |
| * premature wrap arounds. |
| */ |
| time64_t ktime_get_seconds(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| |
| WARN_ON(timekeeping_suspended); |
| return tk->ktime_sec; |
| } |
| EXPORT_SYMBOL_GPL(ktime_get_seconds); |
| |
| /** |
| * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME |
| * |
| * Returns the wall clock seconds since 1970. This replaces the |
| * get_seconds() interface which is not y2038 safe on 32bit systems. |
| * |
| * For 64bit systems the fast access to tk->xtime_sec is preserved. On |
| * 32bit systems the access must be protected with the sequence |
| * counter to provide "atomic" access to the 64bit tk->xtime_sec |
| * value. |
| */ |
| time64_t ktime_get_real_seconds(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| time64_t seconds; |
| unsigned int seq; |
| |
| if (IS_ENABLED(CONFIG_64BIT)) |
| return tk->xtime_sec; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| seconds = tk->xtime_sec; |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return seconds; |
| } |
| EXPORT_SYMBOL_GPL(ktime_get_real_seconds); |
| |
| /** |
| * __ktime_get_real_seconds - The same as ktime_get_real_seconds |
| * but without the sequence counter protect. This internal function |
| * is called just when timekeeping lock is already held. |
| */ |
| time64_t __ktime_get_real_seconds(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| |
| return tk->xtime_sec; |
| } |
| |
| /** |
| * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter |
| * @systime_snapshot: pointer to struct receiving the system time snapshot |
| */ |
| void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long seq; |
| ktime_t base_raw; |
| ktime_t base_real; |
| u64 nsec_raw; |
| u64 nsec_real; |
| u64 now; |
| |
| WARN_ON_ONCE(timekeeping_suspended); |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| |
| now = tk->tkr_mono.read(tk->tkr_mono.clock); |
| systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq; |
| systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq; |
| base_real = ktime_add(tk->tkr_mono.base, |
| tk_core.timekeeper.offs_real); |
| base_raw = tk->tkr_raw.base; |
| nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now); |
| nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now); |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| systime_snapshot->cycles = now; |
| systime_snapshot->real = ktime_add_ns(base_real, nsec_real); |
| systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw); |
| } |
| EXPORT_SYMBOL_GPL(ktime_get_snapshot); |
| |
| /* Scale base by mult/div checking for overflow */ |
| static int scale64_check_overflow(u64 mult, u64 div, u64 *base) |
| { |
| u64 tmp, rem; |
| |
| tmp = div64_u64_rem(*base, div, &rem); |
| |
| if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) || |
| ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem))) |
| return -EOVERFLOW; |
| tmp *= mult; |
| rem *= mult; |
| |
| do_div(rem, div); |
| *base = tmp + rem; |
| return 0; |
| } |
| |
| /** |
| * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval |
| * @history: Snapshot representing start of history |
| * @partial_history_cycles: Cycle offset into history (fractional part) |
| * @total_history_cycles: Total history length in cycles |
| * @discontinuity: True indicates clock was set on history period |
| * @ts: Cross timestamp that should be adjusted using |
| * partial/total ratio |
| * |
| * Helper function used by get_device_system_crosststamp() to correct the |
| * crosstimestamp corresponding to the start of the current interval to the |
| * system counter value (timestamp point) provided by the driver. The |
| * total_history_* quantities are the total history starting at the provided |
| * reference point and ending at the start of the current interval. The cycle |
| * count between the driver timestamp point and the start of the current |
| * interval is partial_history_cycles. |
| */ |
| static int adjust_historical_crosststamp(struct system_time_snapshot *history, |
| u64 partial_history_cycles, |
| u64 total_history_cycles, |
| bool discontinuity, |
| struct system_device_crosststamp *ts) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| u64 corr_raw, corr_real; |
| bool interp_forward; |
| int ret; |
| |
| if (total_history_cycles == 0 || partial_history_cycles == 0) |
| return 0; |
| |
| /* Interpolate shortest distance from beginning or end of history */ |
| interp_forward = partial_history_cycles > total_history_cycles/2 ? |
| true : false; |
| partial_history_cycles = interp_forward ? |
| total_history_cycles - partial_history_cycles : |
| partial_history_cycles; |
| |
| /* |
| * Scale the monotonic raw time delta by: |
| * partial_history_cycles / total_history_cycles |
| */ |
| corr_raw = (u64)ktime_to_ns( |
| ktime_sub(ts->sys_monoraw, history->raw)); |
| ret = scale64_check_overflow(partial_history_cycles, |
| total_history_cycles, &corr_raw); |
| if (ret) |
| return ret; |
| |
| /* |
| * If there is a discontinuity in the history, scale monotonic raw |
| * correction by: |
| * mult(real)/mult(raw) yielding the realtime correction |
| * Otherwise, calculate the realtime correction similar to monotonic |
| * raw calculation |
| */ |
| if (discontinuity) { |
| corr_real = mul_u64_u32_div |
| (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult); |
| } else { |
| corr_real = (u64)ktime_to_ns( |
| ktime_sub(ts->sys_realtime, history->real)); |
| ret = scale64_check_overflow(partial_history_cycles, |
| total_history_cycles, &corr_real); |
| if (ret) |
| return ret; |
| } |
| |
| /* Fixup monotonic raw and real time time values */ |
| if (interp_forward) { |
| ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw); |
| ts->sys_realtime = ktime_add_ns(history->real, corr_real); |
| } else { |
| ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw); |
| ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real); |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * cycle_between - true if test occurs chronologically between before and after |
| */ |
| static bool cycle_between(u64 before, u64 test, u64 after) |
| { |
| if (test > before && test < after) |
| return true; |
| if (test < before && before > after) |
| return true; |
| return false; |
| } |
| |
| /** |
| * get_device_system_crosststamp - Synchronously capture system/device timestamp |
| * @get_time_fn: Callback to get simultaneous device time and |
| * system counter from the device driver |
| * @ctx: Context passed to get_time_fn() |
| * @history_begin: Historical reference point used to interpolate system |
| * time when counter provided by the driver is before the current interval |
| * @xtstamp: Receives simultaneously captured system and device time |
| * |
| * Reads a timestamp from a device and correlates it to system time |
| */ |
| int get_device_system_crosststamp(int (*get_time_fn) |
| (ktime_t *device_time, |
| struct system_counterval_t *sys_counterval, |
| void *ctx), |
| void *ctx, |
| struct system_time_snapshot *history_begin, |
| struct system_device_crosststamp *xtstamp) |
| { |
| struct system_counterval_t system_counterval; |
| struct timekeeper *tk = &tk_core.timekeeper; |
| u64 cycles, now, interval_start; |
| unsigned int clock_was_set_seq = 0; |
| ktime_t base_real, base_raw; |
| u64 nsec_real, nsec_raw; |
| u8 cs_was_changed_seq; |
| unsigned long seq; |
| bool do_interp; |
| int ret; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| /* |
| * Try to synchronously capture device time and a system |
| * counter value calling back into the device driver |
| */ |
| ret = get_time_fn(&xtstamp->device, &system_counterval, ctx); |
| if (ret) |
| return ret; |
| |
| /* |
| * Verify that the clocksource associated with the captured |
| * system counter value is the same as the currently installed |
| * timekeeper clocksource |
| */ |
| if (tk->tkr_mono.clock != system_counterval.cs) |
| return -ENODEV; |
| cycles = system_counterval.cycles; |
| |
| /* |
| * Check whether the system counter value provided by the |
| * device driver is on the current timekeeping interval. |
| */ |
| now = tk->tkr_mono.read(tk->tkr_mono.clock); |
| interval_start = tk->tkr_mono.cycle_last; |
| if (!cycle_between(interval_start, cycles, now)) { |
| clock_was_set_seq = tk->clock_was_set_seq; |
| cs_was_changed_seq = tk->cs_was_changed_seq; |
| cycles = interval_start; |
| do_interp = true; |
| } else { |
| do_interp = false; |
| } |
| |
| base_real = ktime_add(tk->tkr_mono.base, |
| tk_core.timekeeper.offs_real); |
| base_raw = tk->tkr_raw.base; |
| |
| nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, |
| system_counterval.cycles); |
| nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, |
| system_counterval.cycles); |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real); |
| xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw); |
| |
| /* |
| * Interpolate if necessary, adjusting back from the start of the |
| * current interval |
| */ |
| if (do_interp) { |
| u64 partial_history_cycles, total_history_cycles; |
| bool discontinuity; |
| |
| /* |
| * Check that the counter value occurs after the provided |
| * history reference and that the history doesn't cross a |
| * clocksource change |
| */ |
| if (!history_begin || |
| !cycle_between(history_begin->cycles, |
| system_counterval.cycles, cycles) || |
| history_begin->cs_was_changed_seq != cs_was_changed_seq) |
| return -EINVAL; |
| partial_history_cycles = cycles - system_counterval.cycles; |
| total_history_cycles = cycles - history_begin->cycles; |
| discontinuity = |
| history_begin->clock_was_set_seq != clock_was_set_seq; |
| |
| ret = adjust_historical_crosststamp(history_begin, |
| partial_history_cycles, |
| total_history_cycles, |
| discontinuity, xtstamp); |
| if (ret) |
| return ret; |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(get_device_system_crosststamp); |
| |
| /** |
| * do_gettimeofday - Returns the time of day in a timeval |
| * @tv: pointer to the timeval to be set |
| * |
| * NOTE: Users should be converted to using getnstimeofday() |
| */ |
| void do_gettimeofday(struct timeval *tv) |
| { |
| struct timespec64 now; |
| |
| getnstimeofday64(&now); |
| tv->tv_sec = now.tv_sec; |
| tv->tv_usec = now.tv_nsec/1000; |
| } |
| EXPORT_SYMBOL(do_gettimeofday); |
| |
| /** |
| * do_settimeofday64 - Sets the time of day. |
| * @ts: pointer to the timespec64 variable containing the new time |
| * |
| * Sets the time of day to the new time and update NTP and notify hrtimers |
| */ |
| int do_settimeofday64(const struct timespec64 *ts) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct timespec64 ts_delta, xt; |
| unsigned long flags; |
| int ret = 0; |
| |
| if (!timespec64_valid_strict(ts)) |
| return -EINVAL; |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| write_seqcount_begin(&tk_core.seq); |
| |
| timekeeping_forward_now(tk); |
| |
| xt = tk_xtime(tk); |
| ts_delta.tv_sec = ts->tv_sec - xt.tv_sec; |
| ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec; |
| |
| if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta)); |
| |
| tk_set_xtime(tk, ts); |
| out: |
| timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); |
| |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| |
| /* signal hrtimers about time change */ |
| clock_was_set(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(do_settimeofday64); |
| |
| /** |
| * timekeeping_inject_offset - Adds or subtracts from the current time. |
| * @tv: pointer to the timespec variable containing the offset |
| * |
| * Adds or subtracts an offset value from the current time. |
| */ |
| int timekeeping_inject_offset(struct timespec *ts) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long flags; |
| struct timespec64 ts64, tmp; |
| int ret = 0; |
| |
| if (!timespec_inject_offset_valid(ts)) |
| return -EINVAL; |
| |
| ts64 = timespec_to_timespec64(*ts); |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| write_seqcount_begin(&tk_core.seq); |
| |
| timekeeping_forward_now(tk); |
| |
| /* Make sure the proposed value is valid */ |
| tmp = timespec64_add(tk_xtime(tk), ts64); |
| if (timespec64_compare(&tk->wall_to_monotonic, &ts64) > 0 || |
| !timespec64_valid_strict(&tmp)) { |
| ret = -EINVAL; |
| goto error; |
| } |
| |
| tk_xtime_add(tk, &ts64); |
| tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64)); |
| |
| error: /* even if we error out, we forwarded the time, so call update */ |
| timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); |
| |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| |
| /* signal hrtimers about time change */ |
| clock_was_set(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(timekeeping_inject_offset); |
| |
| /** |
| * __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic |
| * |
| */ |
| static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset) |
| { |
| tk->tai_offset = tai_offset; |
| tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0)); |
| } |
| |
| /** |
| * change_clocksource - Swaps clocksources if a new one is available |
| * |
| * Accumulates current time interval and initializes new clocksource |
| */ |
| static int change_clocksource(void *data) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct clocksource *new, *old; |
| unsigned long flags; |
| |
| new = (struct clocksource *) data; |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| write_seqcount_begin(&tk_core.seq); |
| |
| timekeeping_forward_now(tk); |
| /* |
| * If the cs is in module, get a module reference. Succeeds |
| * for built-in code (owner == NULL) as well. |
| */ |
| if (try_module_get(new->owner)) { |
| if (!new->enable || new->enable(new) == 0) { |
| old = tk->tkr_mono.clock; |
| tk_setup_internals(tk, new); |
| if (old->disable) |
| old->disable(old); |
| module_put(old->owner); |
| } else { |
| module_put(new->owner); |
| } |
| } |
| timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); |
| |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| |
| return 0; |
| } |
| |
| /** |
| * timekeeping_notify - Install a new clock source |
| * @clock: pointer to the clock source |
| * |
| * This function is called from clocksource.c after a new, better clock |
| * source has been registered. The caller holds the clocksource_mutex. |
| */ |
| int timekeeping_notify(struct clocksource *clock) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| |
| if (tk->tkr_mono.clock == clock) |
| return 0; |
| stop_machine(change_clocksource, clock, NULL); |
| tick_clock_notify(); |
| return tk->tkr_mono.clock == clock ? 0 : -1; |
| } |
| |
| /** |
| * getrawmonotonic64 - Returns the raw monotonic time in a timespec |
| * @ts: pointer to the timespec64 to be set |
| * |
| * Returns the raw monotonic time (completely un-modified by ntp) |
| */ |
| void getrawmonotonic64(struct timespec64 *ts) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct timespec64 ts64; |
| unsigned long seq; |
| u64 nsecs; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| nsecs = timekeeping_get_ns(&tk->tkr_raw); |
| ts64 = tk->raw_time; |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| timespec64_add_ns(&ts64, nsecs); |
| *ts = ts64; |
| } |
| EXPORT_SYMBOL(getrawmonotonic64); |
| |
| |
| /** |
| * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres |
| */ |
| int timekeeping_valid_for_hres(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long seq; |
| int ret; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| |
| ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES; |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return ret; |
| } |
| |
| /** |
| * timekeeping_max_deferment - Returns max time the clocksource can be deferred |
| */ |
| u64 timekeeping_max_deferment(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long seq; |
| u64 ret; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| |
| ret = tk->tkr_mono.clock->max_idle_ns; |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return ret; |
| } |
| |
| /** |
| * read_persistent_clock - Return time from the persistent clock. |
| * |
| * Weak dummy function for arches that do not yet support it. |
| * Reads the time from the battery backed persistent clock. |
| * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported. |
| * |
| * XXX - Do be sure to remove it once all arches implement it. |
| */ |
| void __weak read_persistent_clock(struct timespec *ts) |
| { |
| ts->tv_sec = 0; |
| ts->tv_nsec = 0; |
| } |
| |
| void __weak read_persistent_clock64(struct timespec64 *ts64) |
| { |
| struct timespec ts; |
| |
| read_persistent_clock(&ts); |
| *ts64 = timespec_to_timespec64(ts); |
| } |
| |
| /** |
| * read_boot_clock64 - Return time of the system start. |
| * |
| * Weak dummy function for arches that do not yet support it. |
| * Function to read the exact time the system has been started. |
| * Returns a timespec64 with tv_sec=0 and tv_nsec=0 if unsupported. |
| * |
| * XXX - Do be sure to remove it once all arches implement it. |
| */ |
| void __weak read_boot_clock64(struct timespec64 *ts) |
| { |
| ts->tv_sec = 0; |
| ts->tv_nsec = 0; |
| } |
| |
| /* Flag for if timekeeping_resume() has injected sleeptime */ |
| static bool sleeptime_injected; |
| |
| /* Flag for if there is a persistent clock on this platform */ |
| static bool persistent_clock_exists; |
| |
| /* |
| * timekeeping_init - Initializes the clocksource and common timekeeping values |
| */ |
| void __init timekeeping_init(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct clocksource *clock; |
| unsigned long flags; |
| struct timespec64 now, boot, tmp; |
| |
| read_persistent_clock64(&now); |
| if (!timespec64_valid_strict(&now)) { |
| pr_warn("WARNING: Persistent clock returned invalid value!\n" |
| " Check your CMOS/BIOS settings.\n"); |
| now.tv_sec = 0; |
| now.tv_nsec = 0; |
| } else if (now.tv_sec || now.tv_nsec) |
| persistent_clock_exists = true; |
| |
| read_boot_clock64(&boot); |
| if (!timespec64_valid_strict(&boot)) { |
| pr_warn("WARNING: Boot clock returned invalid value!\n" |
| " Check your CMOS/BIOS settings.\n"); |
| boot.tv_sec = 0; |
| boot.tv_nsec = 0; |
| } |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| write_seqcount_begin(&tk_core.seq); |
| ntp_init(); |
| |
| clock = clocksource_default_clock(); |
| if (clock->enable) |
| clock->enable(clock); |
| tk_setup_internals(tk, clock); |
| |
| tk_set_xtime(tk, &now); |
| tk->raw_time.tv_sec = 0; |
| tk->raw_time.tv_nsec = 0; |
| if (boot.tv_sec == 0 && boot.tv_nsec == 0) |
| boot = tk_xtime(tk); |
| |
| set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec); |
| tk_set_wall_to_mono(tk, tmp); |
| |
| timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET); |
| |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| } |
| |
| /* time in seconds when suspend began for persistent clock */ |
| static struct timespec64 timekeeping_suspend_time; |
| |
| /** |
| * __timekeeping_inject_sleeptime - Internal function to add sleep interval |
| * @delta: pointer to a timespec delta value |
| * |
| * Takes a timespec offset measuring a suspend interval and properly |
| * adds the sleep offset to the timekeeping variables. |
| */ |
| static void __timekeeping_inject_sleeptime(struct timekeeper *tk, |
| struct timespec64 *delta) |
| { |
| if (!timespec64_valid_strict(delta)) { |
| printk_deferred(KERN_WARNING |
| "__timekeeping_inject_sleeptime: Invalid " |
| "sleep delta value!\n"); |
| return; |
| } |
| tk_xtime_add(tk, delta); |
| tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta)); |
| tk_update_sleep_time(tk, timespec64_to_ktime(*delta)); |
| tk_debug_account_sleep_time(delta); |
| } |
| |
| #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE) |
| /** |
| * We have three kinds of time sources to use for sleep time |
| * injection, the preference order is: |
| * 1) non-stop clocksource |
| * 2) persistent clock (ie: RTC accessible when irqs are off) |
| * 3) RTC |
| * |
| * 1) and 2) are used by timekeeping, 3) by RTC subsystem. |
| * If system has neither 1) nor 2), 3) will be used finally. |
| * |
| * |
| * If timekeeping has injected sleeptime via either 1) or 2), |
| * 3) becomes needless, so in this case we don't need to call |
| * rtc_resume(), and this is what timekeeping_rtc_skipresume() |
| * means. |
| */ |
| bool timekeeping_rtc_skipresume(void) |
| { |
| return sleeptime_injected; |
| } |
| |
| /** |
| * 1) can be determined whether to use or not only when doing |
| * timekeeping_resume() which is invoked after rtc_suspend(), |
| * so we can't skip rtc_suspend() surely if system has 1). |
| * |
| * But if system has 2), 2) will definitely be used, so in this |
| * case we don't need to call rtc_suspend(), and this is what |
| * timekeeping_rtc_skipsuspend() means. |
| */ |
| bool timekeeping_rtc_skipsuspend(void) |
| { |
| return persistent_clock_exists; |
| } |
| |
| /** |
| * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values |
| * @delta: pointer to a timespec64 delta value |
| * |
| * This hook is for architectures that cannot support read_persistent_clock64 |
| * because their RTC/persistent clock is only accessible when irqs are enabled. |
| * and also don't have an effective nonstop clocksource. |
| * |
| * This function should only be called by rtc_resume(), and allows |
| * a suspend offset to be injected into the timekeeping values. |
| */ |
| void timekeeping_inject_sleeptime64(struct timespec64 *delta) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long flags; |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| write_seqcount_begin(&tk_core.seq); |
| |
| timekeeping_forward_now(tk); |
| |
| __timekeeping_inject_sleeptime(tk, delta); |
| |
| timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET); |
| |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| |
| /* signal hrtimers about time change */ |
| clock_was_set(); |
| } |
| #endif |
| |
| /** |
| * timekeeping_resume - Resumes the generic timekeeping subsystem. |
| */ |
| void timekeeping_resume(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct clocksource *clock = tk->tkr_mono.clock; |
| unsigned long flags; |
| struct timespec64 ts_new, ts_delta; |
| u64 cycle_now; |
| |
| sleeptime_injected = false; |
| read_persistent_clock64(&ts_new); |
| |
| clockevents_resume(); |
| clocksource_resume(); |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| write_seqcount_begin(&tk_core.seq); |
| |
| /* |
| * After system resumes, we need to calculate the suspended time and |
| * compensate it for the OS time. There are 3 sources that could be |
| * used: Nonstop clocksource during suspend, persistent clock and rtc |
| * device. |
| * |
| * One specific platform may have 1 or 2 or all of them, and the |
| * preference will be: |
| * suspend-nonstop clocksource -> persistent clock -> rtc |
| * The less preferred source will only be tried if there is no better |
| * usable source. The rtc part is handled separately in rtc core code. |
| */ |
| cycle_now = tk->tkr_mono.read(clock); |
| if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) && |
| cycle_now > tk->tkr_mono.cycle_last) { |
| u64 nsec, cyc_delta; |
| |
| cyc_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, |
| tk->tkr_mono.mask); |
| nsec = mul_u64_u32_shr(cyc_delta, clock->mult, clock->shift); |
| ts_delta = ns_to_timespec64(nsec); |
| sleeptime_injected = true; |
| } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) { |
| ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time); |
| sleeptime_injected = true; |
| } |
| |
| if (sleeptime_injected) |
| __timekeeping_inject_sleeptime(tk, &ts_delta); |
| |
| /* Re-base the last cycle value */ |
| tk->tkr_mono.cycle_last = cycle_now; |
| tk->tkr_raw.cycle_last = cycle_now; |
| |
| tk->ntp_error = 0; |
| timekeeping_suspended = 0; |
| timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET); |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| |
| touch_softlockup_watchdog(); |
| |
| tick_resume(); |
| hrtimers_resume(); |
| } |
| |
| int timekeeping_suspend(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long flags; |
| struct timespec64 delta, delta_delta; |
| static struct timespec64 old_delta; |
| |
| read_persistent_clock64(&timekeeping_suspend_time); |
| |
| /* |
| * On some systems the persistent_clock can not be detected at |
| * timekeeping_init by its return value, so if we see a valid |
| * value returned, update the persistent_clock_exists flag. |
| */ |
| if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec) |
| persistent_clock_exists = true; |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| write_seqcount_begin(&tk_core.seq); |
| timekeeping_forward_now(tk); |
| timekeeping_suspended = 1; |
| |
| if (persistent_clock_exists) { |
| /* |
| * To avoid drift caused by repeated suspend/resumes, |
| * which each can add ~1 second drift error, |
| * try to compensate so the difference in system time |
| * and persistent_clock time stays close to constant. |
| */ |
| delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time); |
| delta_delta = timespec64_sub(delta, old_delta); |
| if (abs(delta_delta.tv_sec) >= 2) { |
| /* |
| * if delta_delta is too large, assume time correction |
| * has occurred and set old_delta to the current delta. |
| */ |
| old_delta = delta; |
| } else { |
| /* Otherwise try to adjust old_system to compensate */ |
| timekeeping_suspend_time = |
| timespec64_add(timekeeping_suspend_time, delta_delta); |
| } |
| } |
| |
| timekeeping_update(tk, TK_MIRROR); |
| halt_fast_timekeeper(tk); |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| |
| tick_suspend(); |
| clocksource_suspend(); |
| clockevents_suspend(); |
| |
| return 0; |
| } |
| |
| /* sysfs resume/suspend bits for timekeeping */ |
| static struct syscore_ops timekeeping_syscore_ops = { |
| .resume = timekeeping_resume, |
| .suspend = timekeeping_suspend, |
| }; |
| |
| static int __init timekeeping_init_ops(void) |
| { |
| register_syscore_ops(&timekeeping_syscore_ops); |
| return 0; |
| } |
| device_initcall(timekeeping_init_ops); |
| |
| /* |
| * Apply a multiplier adjustment to the timekeeper |
| */ |
| static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk, |
| s64 offset, |
| bool negative, |
| int adj_scale) |
| { |
| s64 interval = tk->cycle_interval; |
| s32 mult_adj = 1; |
| |
| if (negative) { |
| mult_adj = -mult_adj; |
| interval = -interval; |
| offset = -offset; |
| } |
| mult_adj <<= adj_scale; |
| interval <<= adj_scale; |
| offset <<= adj_scale; |
| |
| /* |
| * So the following can be confusing. |
| * |
| * To keep things simple, lets assume mult_adj == 1 for now. |
| * |
| * When mult_adj != 1, remember that the interval and offset values |
| * have been appropriately scaled so the math is the same. |
| * |
| * The basic idea here is that we're increasing the multiplier |
| * by one, this causes the xtime_interval to be incremented by |
| * one cycle_interval. This is because: |
| * xtime_interval = cycle_interval * mult |
| * So if mult is being incremented by one: |
| * xtime_interval = cycle_interval * (mult + 1) |
| * Its the same as: |
| * xtime_interval = (cycle_interval * mult) + cycle_interval |
| * Which can be shortened to: |
| * xtime_interval += cycle_interval |
| * |
| * So offset stores the non-accumulated cycles. Thus the current |
| * time (in shifted nanoseconds) is: |
| * now = (offset * adj) + xtime_nsec |
| * Now, even though we're adjusting the clock frequency, we have |
| * to keep time consistent. In other words, we can't jump back |
| * in time, and we also want to avoid jumping forward in time. |
| * |
| * So given the same offset value, we need the time to be the same |
| * both before and after the freq adjustment. |
| * now = (offset * adj_1) + xtime_nsec_1 |
| * now = (offset * adj_2) + xtime_nsec_2 |
| * So: |
| * (offset * adj_1) + xtime_nsec_1 = |
| * (offset * adj_2) + xtime_nsec_2 |
| * And we know: |
| * adj_2 = adj_1 + 1 |
| * So: |
| * (offset * adj_1) + xtime_nsec_1 = |
| * (offset * (adj_1+1)) + xtime_nsec_2 |
| * (offset * adj_1) + xtime_nsec_1 = |
| * (offset * adj_1) + offset + xtime_nsec_2 |
| * Canceling the sides: |
| * xtime_nsec_1 = offset + xtime_nsec_2 |
| * Which gives us: |
| * xtime_nsec_2 = xtime_nsec_1 - offset |
| * Which simplfies to: |
| * xtime_nsec -= offset |
| * |
| * XXX - TODO: Doc ntp_error calculation. |
| */ |
| if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) { |
| /* NTP adjustment caused clocksource mult overflow */ |
| WARN_ON_ONCE(1); |
| return; |
| } |
| |
| tk->tkr_mono.mult += mult_adj; |
| tk->xtime_interval += interval; |
| tk->tkr_mono.xtime_nsec -= offset; |
| tk->ntp_error -= (interval - offset) << tk->ntp_error_shift; |
| } |
| |
| /* |
| * Calculate the multiplier adjustment needed to match the frequency |
| * specified by NTP |
| */ |
| static __always_inline void timekeeping_freqadjust(struct timekeeper *tk, |
| s64 offset) |
| { |
| s64 interval = tk->cycle_interval; |
| s64 xinterval = tk->xtime_interval; |
| u32 base = tk->tkr_mono.clock->mult; |
| u32 max = tk->tkr_mono.clock->maxadj; |
| u32 cur_adj = tk->tkr_mono.mult; |
| s64 tick_error; |
| bool negative; |
| u32 adj_scale; |
| |
| /* Remove any current error adj from freq calculation */ |
| if (tk->ntp_err_mult) |
| xinterval -= tk->cycle_interval; |
| |
| tk->ntp_tick = ntp_tick_length(); |
| |
| /* Calculate current error per tick */ |
| tick_error = ntp_tick_length() >> tk->ntp_error_shift; |
| tick_error -= (xinterval + tk->xtime_remainder); |
| |
| /* Don't worry about correcting it if its small */ |
| if (likely((tick_error >= 0) && (tick_error <= interval))) |
| return; |
| |
| /* preserve the direction of correction */ |
| negative = (tick_error < 0); |
| |
| /* If any adjustment would pass the max, just return */ |
| if (negative && (cur_adj - 1) <= (base - max)) |
| return; |
| if (!negative && (cur_adj + 1) >= (base + max)) |
| return; |
| /* |
| * Sort out the magnitude of the correction, but |
| * avoid making so large a correction that we go |
| * over the max adjustment. |
| */ |
| adj_scale = 0; |
| tick_error = abs(tick_error); |
| while (tick_error > interval) { |
| u32 adj = 1 << (adj_scale + 1); |
| |
| /* Check if adjustment gets us within 1 unit from the max */ |
| if (negative && (cur_adj - adj) <= (base - max)) |
| break; |
| if (!negative && (cur_adj + adj) >= (base + max)) |
| break; |
| |
| adj_scale++; |
| tick_error >>= 1; |
| } |
| |
| /* scale the corrections */ |
| timekeeping_apply_adjustment(tk, offset, negative, adj_scale); |
| } |
| |
| /* |
| * Adjust the timekeeper's multiplier to the correct frequency |
| * and also to reduce the accumulated error value. |
| */ |
| static void timekeeping_adjust(struct timekeeper *tk, s64 offset) |
| { |
| /* Correct for the current frequency error */ |
| timekeeping_freqadjust(tk, offset); |
| |
| /* Next make a small adjustment to fix any cumulative error */ |
| if (!tk->ntp_err_mult && (tk->ntp_error > 0)) { |
| tk->ntp_err_mult = 1; |
| timekeeping_apply_adjustment(tk, offset, 0, 0); |
| } else if (tk->ntp_err_mult && (tk->ntp_error <= 0)) { |
| /* Undo any existing error adjustment */ |
| timekeeping_apply_adjustment(tk, offset, 1, 0); |
| tk->ntp_err_mult = 0; |
| } |
| |
| if (unlikely(tk->tkr_mono.clock->maxadj && |
| (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult) |
| > tk->tkr_mono.clock->maxadj))) { |
| printk_once(KERN_WARNING |
| "Adjusting %s more than 11%% (%ld vs %ld)\n", |
| tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult, |
| (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj); |
| } |
| |
| /* |
| * It may be possible that when we entered this function, xtime_nsec |
| * was very small. Further, if we're slightly speeding the clocksource |
| * in the code above, its possible the required corrective factor to |
| * xtime_nsec could cause it to underflow. |
| * |
| * Now, since we already accumulated the second, cannot simply roll |
| * the accumulated second back, since the NTP subsystem has been |
| * notified via second_overflow. So instead we push xtime_nsec forward |
| * by the amount we underflowed, and add that amount into the error. |
| * |
| * We'll correct this error next time through this function, when |
| * xtime_nsec is not as small. |
| */ |
| if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) { |
| s64 neg = -(s64)tk->tkr_mono.xtime_nsec; |
| tk->tkr_mono.xtime_nsec = 0; |
| tk->ntp_error += neg << tk->ntp_error_shift; |
| } |
| } |
| |
| /** |
| * accumulate_nsecs_to_secs - Accumulates nsecs into secs |
| * |
| * Helper function that accumulates the nsecs greater than a second |
| * from the xtime_nsec field to the xtime_secs field. |
| * It also calls into the NTP code to handle leapsecond processing. |
| * |
| */ |
| static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk) |
| { |
| u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift; |
| unsigned int clock_set = 0; |
| |
| while (tk->tkr_mono.xtime_nsec >= nsecps) { |
| int leap; |
| |
| tk->tkr_mono.xtime_nsec -= nsecps; |
| tk->xtime_sec++; |
| |
| /* Figure out if its a leap sec and apply if needed */ |
| leap = second_overflow(tk->xtime_sec); |
| if (unlikely(leap)) { |
| struct timespec64 ts; |
| |
| tk->xtime_sec += leap; |
| |
| ts.tv_sec = leap; |
| ts.tv_nsec = 0; |
| tk_set_wall_to_mono(tk, |
| timespec64_sub(tk->wall_to_monotonic, ts)); |
| |
| __timekeeping_set_tai_offset(tk, tk->tai_offset - leap); |
| |
| clock_set = TK_CLOCK_WAS_SET; |
| } |
| } |
| return clock_set; |
| } |
| |
| /** |
| * logarithmic_accumulation - shifted accumulation of cycles |
| * |
| * This functions accumulates a shifted interval of cycles into |
| * into a shifted interval nanoseconds. Allows for O(log) accumulation |
| * loop. |
| * |
| * Returns the unconsumed cycles. |
| */ |
| static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset, |
| u32 shift, unsigned int *clock_set) |
| { |
| u64 interval = tk->cycle_interval << shift; |
| u64 raw_nsecs; |
| |
| /* If the offset is smaller than a shifted interval, do nothing */ |
| if (offset < interval) |
| return offset; |
| |
| /* Accumulate one shifted interval */ |
| offset -= interval; |
| tk->tkr_mono.cycle_last += interval; |
| tk->tkr_raw.cycle_last += interval; |
| |
| tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift; |
| *clock_set |= accumulate_nsecs_to_secs(tk); |
| |
| /* Accumulate raw time */ |
| 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->raw_time.tv_nsec = raw_nsecs; |
| |
| /* Accumulate error between NTP and clock interval */ |
| tk->ntp_error += tk->ntp_tick << shift; |
| tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) << |
| (tk->ntp_error_shift + shift); |
| |
| return offset; |
| } |
| |
| /** |
| * update_wall_time - Uses the current clocksource to increment the wall time |
| * |
| */ |
| void update_wall_time(void) |
| { |
| struct timekeeper *real_tk = &tk_core.timekeeper; |
| struct timekeeper *tk = &shadow_timekeeper; |
| u64 offset; |
| int shift = 0, maxshift; |
| unsigned int clock_set = 0; |
| unsigned long flags; |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| |
| /* Make sure we're fully resumed: */ |
| if (unlikely(timekeeping_suspended)) |
| goto out; |
| |
| #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET |
| offset = real_tk->cycle_interval; |
| #else |
| offset = clocksource_delta(tk->tkr_mono.read(tk->tkr_mono.clock), |
| tk->tkr_mono.cycle_last, tk->tkr_mono.mask); |
| #endif |
| |
| /* Check if there's really nothing to do */ |
| if (offset < real_tk->cycle_interval) |
| goto out; |
| |
| /* Do some additional sanity checking */ |
| timekeeping_check_update(real_tk, offset); |
| |
| /* |
| * With NO_HZ we may have to accumulate many cycle_intervals |
| * (think "ticks") worth of time at once. To do this efficiently, |
| * we calculate the largest doubling multiple of cycle_intervals |
| * that is smaller than the offset. We then accumulate that |
| * chunk in one go, and then try to consume the next smaller |
| * doubled multiple. |
| */ |
| shift = ilog2(offset) - ilog2(tk->cycle_interval); |
| shift = max(0, shift); |
| /* Bound shift to one less than what overflows tick_length */ |
| maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1; |
| shift = min(shift, maxshift); |
| while (offset >= tk->cycle_interval) { |
| offset = logarithmic_accumulation(tk, offset, shift, |
| &clock_set); |
| if (offset < tk->cycle_interval<<shift) |
| shift--; |
| } |
| |
| /* correct the clock when NTP error is too big */ |
| timekeeping_adjust(tk, offset); |
| |
| /* |
| * 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 |
| */ |
| clock_set |= accumulate_nsecs_to_secs(tk); |
| |
| write_seqcount_begin(&tk_core.seq); |
| /* |
| * Update the real timekeeper. |
| * |
| * We could avoid this memcpy by switching pointers, but that |
| * requires changes to all other timekeeper usage sites as |
| * well, i.e. move the timekeeper pointer getter into the |
| * spinlocked/seqcount protected sections. And we trade this |
| * memcpy under the tk_core.seq against one before we start |
| * updating. |
| */ |
| timekeeping_update(tk, clock_set); |
| memcpy(real_tk, tk, sizeof(*tk)); |
| /* The memcpy must come last. Do not put anything here! */ |
| write_seqcount_end(&tk_core.seq); |
| out: |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| if (clock_set) |
| /* Have to call _delayed version, since in irq context*/ |
| clock_was_set_delayed(); |
| } |
| |
| /** |
| * getboottime64 - Return the real time of system boot. |
| * @ts: pointer to the timespec64 to be set |
| * |
| * Returns the wall-time of boot in a timespec64. |
| * |
| * This is based on the wall_to_monotonic offset and the total suspend |
| * time. Calls to settimeofday will affect the value returned (which |
| * basically means that however wrong your real time clock is at boot time, |
| * you get the right time here). |
| */ |
| void getboottime64(struct timespec64 *ts) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot); |
| |
| *ts = ktime_to_timespec64(t); |
| } |
| EXPORT_SYMBOL_GPL(getboottime64); |
| |
| unsigned long get_seconds(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| |
| return tk->xtime_sec; |
| } |
| EXPORT_SYMBOL(get_seconds); |
| |
| struct timespec __current_kernel_time(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| |
| return timespec64_to_timespec(tk_xtime(tk)); |
| } |
| |
| struct timespec64 current_kernel_time64(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct timespec64 now; |
| unsigned long seq; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| |
| now = tk_xtime(tk); |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return now; |
| } |
| EXPORT_SYMBOL(current_kernel_time64); |
| |
| struct timespec64 get_monotonic_coarse64(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct timespec64 now, mono; |
| unsigned long seq; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| |
| now = tk_xtime(tk); |
| mono = tk->wall_to_monotonic; |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec, |
| now.tv_nsec + mono.tv_nsec); |
| |
| return now; |
| } |
| EXPORT_SYMBOL(get_monotonic_coarse64); |
| |
| /* |
| * Must hold jiffies_lock |
| */ |
| void do_timer(unsigned long ticks) |
| { |
| jiffies_64 += ticks; |
| calc_global_load(ticks); |
| } |
| |
| /** |
| * ktime_get_update_offsets_now - hrtimer helper |
| * @cwsseq: pointer to check and store the clock was set sequence number |
| * @offs_real: pointer to storage for monotonic -> realtime offset |
| * @offs_boot: pointer to storage for monotonic -> boottime offset |
| * @offs_tai: pointer to storage for monotonic -> clock tai offset |
| * |
| * Returns current monotonic time and updates the offsets if the |
| * sequence number in @cwsseq and timekeeper.clock_was_set_seq are |
| * different. |
| * |
| * Called from hrtimer_interrupt() or retrigger_next_event() |
| */ |
| ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real, |
| ktime_t *offs_boot, ktime_t *offs_tai) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned int seq; |
| ktime_t base; |
| u64 nsecs; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| |
| base = tk->tkr_mono.base; |
| nsecs = timekeeping_get_ns(&tk->tkr_mono); |
| base = ktime_add_ns(base, nsecs); |
| |
| if (*cwsseq != tk->clock_was_set_seq) { |
| *cwsseq = tk->clock_was_set_seq; |
| *offs_real = tk->offs_real; |
| *offs_boot = tk->offs_boot; |
| *offs_tai = tk->offs_tai; |
| } |
| |
| /* Handle leapsecond insertion adjustments */ |
| if (unlikely(base >= tk->next_leap_ktime)) |
| *offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0)); |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return base; |
| } |
| |
| /** |
| * do_adjtimex() - Accessor function to NTP __do_adjtimex function |
| */ |
| int do_adjtimex(struct timex *txc) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long flags; |
| struct timespec64 ts; |
| s32 orig_tai, tai; |
| int ret; |
| |
| /* Validate the data before disabling interrupts */ |
| ret = ntp_validate_timex(txc); |
| if (ret) |
| return ret; |
| |
| if (txc->modes & ADJ_SETOFFSET) { |
| struct timespec delta; |
| delta.tv_sec = txc->time.tv_sec; |
| delta.tv_nsec = txc->time.tv_usec; |
| if (!(txc->modes & ADJ_NANO)) |
| delta.tv_nsec *= 1000; |
| ret = timekeeping_inject_offset(&delta); |
| if (ret) |
| return ret; |
| } |
| |
| getnstimeofday64(&ts); |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| write_seqcount_begin(&tk_core.seq); |
| |
| orig_tai = tai = tk->tai_offset; |
| ret = __do_adjtimex(txc, &ts, &tai); |
| |
| if (tai != orig_tai) { |
| __timekeeping_set_tai_offset(tk, tai); |
| timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET); |
| } |
| tk_update_leap_state(tk); |
| |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| |
| if (tai != orig_tai) |
| clock_was_set(); |
| |
| ntp_notify_cmos_timer(); |
| |
| return ret; |
| } |
| |
| #ifdef CONFIG_NTP_PPS |
| /** |
| * hardpps() - Accessor function to NTP __hardpps function |
| */ |
| void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts) |
| { |
| unsigned long flags; |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| write_seqcount_begin(&tk_core.seq); |
| |
| __hardpps(phase_ts, raw_ts); |
| |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| } |
| EXPORT_SYMBOL(hardpps); |
| #endif |
| |
| /** |
| * xtime_update() - advances the timekeeping infrastructure |
| * @ticks: number of ticks, that have elapsed since the last call. |
| * |
| * Must be called with interrupts disabled. |
| */ |
| void xtime_update(unsigned long ticks) |
| { |
| write_seqlock(&jiffies_lock); |
| do_timer(ticks); |
| write_sequnlock(&jiffies_lock); |
| update_wall_time(); |
| } |