| /* |
| * 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/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; |
| |
| /* 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; |
| |
| 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; |
| 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->xtime_nsec >> tk->shift); |
| return ts; |
| } |
| |
| 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; |
| } |
| |
| 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_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.tv64 != timespec64_to_ktime(tmp).tv64); |
| tk->wall_to_monotonic = wtm; |
| set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec); |
| tk->offs_real = timespec64_to_ktime(tmp); |
| tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0)); |
| } |
| |
| static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta) |
| { |
| tk->offs_boot = ktime_add(tk->offs_boot, delta); |
| } |
| |
| /** |
| * tk_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) |
| { |
| cycle_t interval; |
| u64 tmp, ntpinterval; |
| struct clocksource *old_clock; |
| |
| old_clock = tk->clock; |
| tk->clock = clock; |
| tk->cycle_last = clock->cycle_last = clock->read(clock); |
| |
| /* 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 = (cycle_t) tmp; |
| tk->cycle_interval = interval; |
| |
| /* Go back from cycles -> shifted ns */ |
| tk->xtime_interval = (u64) interval * clock->mult; |
| tk->xtime_remainder = ntpinterval - tk->xtime_interval; |
| tk->raw_interval = |
| ((u64) 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->xtime_nsec >>= -shift_change; |
| else |
| tk->xtime_nsec <<= shift_change; |
| } |
| tk->shift = clock->shift; |
| |
| tk->ntp_error = 0; |
| tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->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; |
| } |
| |
| /* 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 s64 timekeeping_get_ns(struct timekeeper *tk) |
| { |
| cycle_t cycle_now, cycle_delta; |
| struct clocksource *clock; |
| s64 nsec; |
| |
| /* read clocksource: */ |
| clock = tk->clock; |
| cycle_now = clock->read(clock); |
| |
| /* calculate the delta since the last update_wall_time: */ |
| cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
| |
| nsec = cycle_delta * tk->mult + tk->xtime_nsec; |
| nsec >>= tk->shift; |
| |
| /* If arch requires, add in get_arch_timeoffset() */ |
| return nsec + arch_gettimeoffset(); |
| } |
| |
| static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk) |
| { |
| cycle_t cycle_now, cycle_delta; |
| struct clocksource *clock; |
| s64 nsec; |
| |
| /* read clocksource: */ |
| clock = tk->clock; |
| cycle_now = clock->read(clock); |
| |
| /* calculate the delta since the last update_wall_time: */ |
| cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; |
| |
| /* convert delta to nanoseconds. */ |
| nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); |
| |
| /* If arch requires, add in get_arch_timeoffset() */ |
| return nsec + arch_gettimeoffset(); |
| } |
| |
| #ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD |
| |
| static inline void update_vsyscall(struct timekeeper *tk) |
| { |
| struct timespec xt; |
| |
| xt = tk_xtime(tk); |
| update_vsyscall_old(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult); |
| } |
| |
| 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; |
| tk->ntp_error -= (1ULL << tk->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); |
| |
| /* |
| * Update the ktime_t based scalar nsec members of the timekeeper |
| */ |
| static inline void tk_update_ktime_data(struct timekeeper *tk) |
| { |
| s64 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 |
| */ |
| nsec = (s64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec); |
| nsec *= NSEC_PER_SEC; |
| nsec += tk->wall_to_monotonic.tv_nsec; |
| tk->base_mono = ns_to_ktime(nsec); |
| |
| /* Update the monotonic raw base */ |
| tk->base_raw = timespec64_to_ktime(tk->raw_time); |
| } |
| |
| /* 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(); |
| } |
| update_vsyscall(tk); |
| update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET); |
| |
| tk_update_ktime_data(tk); |
| |
| 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) |
| { |
| 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)arch_gettimeoffset() << tk->shift; |
| |
| tk_normalize_xtime(tk); |
| |
| nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->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; |
| s64 nsecs = 0; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| |
| ts->tv_sec = tk->xtime_sec; |
| nsecs = timekeeping_get_ns(tk); |
| |
| } 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 timespec to be set |
| * |
| * Returns the time of day in a timespec (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; |
| s64 nsecs; |
| |
| WARN_ON(timekeeping_suspended); |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| base = tk->base_mono; |
| nsecs = timekeeping_get_ns(tk); |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return ktime_add_ns(base, nsecs); |
| } |
| EXPORT_SYMBOL_GPL(ktime_get); |
| |
| 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]; |
| s64 nsecs; |
| |
| WARN_ON(timekeeping_suspended); |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| base = ktime_add(tk->base_mono, *offset); |
| nsecs = timekeeping_get_ns(tk); |
| |
| } 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; |
| s64 nsecs; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| base = tk->base_raw; |
| nsecs = timekeeping_get_ns_raw(tk); |
| |
| } 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. |
| */ |
| void ktime_get_ts64(struct timespec64 *ts) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct timespec64 tomono; |
| s64 nsec; |
| unsigned int seq; |
| |
| WARN_ON(timekeeping_suspended); |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| ts->tv_sec = tk->xtime_sec; |
| nsec = timekeeping_get_ns(tk); |
| 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); |
| |
| #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. |
| */ |
| void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long seq; |
| s64 nsecs_raw, nsecs_real; |
| |
| WARN_ON_ONCE(timekeeping_suspended); |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| |
| *ts_raw = timespec64_to_timespec(tk->raw_time); |
| ts_real->tv_sec = tk->xtime_sec; |
| ts_real->tv_nsec = 0; |
| |
| nsecs_raw = timekeeping_get_ns_raw(tk); |
| nsecs_real = timekeeping_get_ns(tk); |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| timespec_add_ns(ts_raw, nsecs_raw); |
| timespec_add_ns(ts_real, nsecs_real); |
| } |
| 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 |
| * |
| * 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_settimeofday - Sets the time of day |
| * @tv: pointer to the timespec variable containing the new time |
| * |
| * Sets the time of day to the new time and update NTP and notify hrtimers |
| */ |
| int do_settimeofday(const struct timespec *tv) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct timespec64 ts_delta, xt, tmp; |
| unsigned long flags; |
| |
| if (!timespec_valid_strict(tv)) |
| 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 = tv->tv_sec - xt.tv_sec; |
| ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec; |
| |
| tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta)); |
| |
| tmp = timespec_to_timespec64(*tv); |
| tk_set_xtime(tk, &tmp); |
| |
| 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 0; |
| } |
| EXPORT_SYMBOL(do_settimeofday); |
| |
| /** |
| * 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 ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) |
| 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_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_get_tai_offset - Returns current TAI offset from UTC |
| * |
| */ |
| s32 timekeeping_get_tai_offset(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned int seq; |
| s32 ret; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| ret = tk->tai_offset; |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return ret; |
| } |
| |
| /** |
| * __timekeeping_set_tai_offset - Lock free worker function |
| * |
| */ |
| 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)); |
| } |
| |
| /** |
| * timekeeping_set_tai_offset - Sets the current TAI offset from UTC |
| * |
| */ |
| void timekeeping_set_tai_offset(s32 tai_offset) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long flags; |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| write_seqcount_begin(&tk_core.seq); |
| __timekeeping_set_tai_offset(tk, tai_offset); |
| timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET); |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| clock_was_set(); |
| } |
| |
| /** |
| * 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->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->clock == clock) |
| return 0; |
| stop_machine(change_clocksource, clock, NULL); |
| tick_clock_notify(); |
| return tk->clock == clock ? 0 : -1; |
| } |
| |
| /** |
| * getrawmonotonic - Returns the raw monotonic time in a timespec |
| * @ts: pointer to the timespec to be set |
| * |
| * Returns the raw monotonic time (completely un-modified by ntp) |
| */ |
| void getrawmonotonic(struct timespec *ts) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct timespec64 ts64; |
| unsigned long seq; |
| s64 nsecs; |
| |
| do { |
| seq = read_seqcount_begin(&tk_core.seq); |
| nsecs = timekeeping_get_ns_raw(tk); |
| ts64 = tk->raw_time; |
| |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| timespec64_add_ns(&ts64, nsecs); |
| *ts = timespec64_to_timespec(ts64); |
| } |
| EXPORT_SYMBOL(getrawmonotonic); |
| |
| /** |
| * 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->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->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; |
| } |
| |
| /** |
| * read_boot_clock - 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 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_boot_clock(struct timespec *ts) |
| { |
| ts->tv_sec = 0; |
| ts->tv_nsec = 0; |
| } |
| |
| /* |
| * 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; |
| struct timespec ts; |
| |
| read_persistent_clock(&ts); |
| now = timespec_to_timespec64(ts); |
| 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_exist = true; |
| |
| read_boot_clock(&ts); |
| boot = timespec_to_timespec64(ts); |
| 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; |
| tk->base_raw.tv64 = 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); |
| |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| } |
| |
| /* time in seconds when suspend began */ |
| 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); |
| } |
| |
| /** |
| * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values |
| * @delta: pointer to a timespec delta value |
| * |
| * This hook is for architectures that cannot support read_persistent_clock |
| * because their RTC/persistent clock is only accessible when irqs are enabled. |
| * |
| * 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) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct timespec64 tmp; |
| 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(&tk_core.seq); |
| |
| timekeeping_forward_now(tk); |
| |
| tmp = timespec_to_timespec64(*delta); |
| __timekeeping_inject_sleeptime(tk, &tmp); |
| |
| 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(); |
| } |
| |
| /** |
| * 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) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| struct clocksource *clock = tk->clock; |
| unsigned long flags; |
| struct timespec64 ts_new, ts_delta; |
| struct timespec tmp; |
| cycle_t cycle_now, cycle_delta; |
| bool suspendtime_found = false; |
| |
| read_persistent_clock(&tmp); |
| ts_new = timespec_to_timespec64(tmp); |
| |
| 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 = 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_timespec64(nsec); |
| suspendtime_found = true; |
| } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) { |
| ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time); |
| suspendtime_found = true; |
| } |
| |
| if (suspendtime_found) |
| __timekeeping_inject_sleeptime(tk, &ts_delta); |
| |
| /* Re-base the last cycle value */ |
| tk->cycle_last = clock->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(); |
| |
| clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); |
| |
| /* Resume hrtimers */ |
| hrtimers_resume(); |
| } |
| |
| static int timekeeping_suspend(void) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| unsigned long flags; |
| struct timespec64 delta, delta_delta; |
| static struct timespec64 old_delta; |
| struct timespec tmp; |
| |
| read_persistent_clock(&tmp); |
| timekeeping_suspend_time = timespec_to_timespec64(tmp); |
| |
| /* |
| * 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_exist = true; |
| |
| raw_spin_lock_irqsave(&timekeeper_lock, flags); |
| write_seqcount_begin(&tk_core.seq); |
| timekeeping_forward_now(tk); |
| 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. |
| */ |
| 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 occured 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); |
| write_seqcount_end(&tk_core.seq); |
| raw_spin_unlock_irqrestore(&timekeeper_lock, flags); |
| |
| clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); |
| 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); |
| |
| /* |
| * If the error is already larger, we look ahead even further |
| * to compensate for late or lost adjustments. |
| */ |
| static __always_inline int timekeeping_bigadjust(struct timekeeper *tk, |
| s64 error, s64 *interval, |
| s64 *offset) |
| { |
| 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; |
| |
| *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; |
| 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 (unlikely(tk->clock->maxadj && |
| (tk->mult + adj > tk->clock->mult + tk->clock->maxadj))) { |
| printk_deferred_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. |
| * |
| * When 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. |
| */ |
| tk->mult += adj; |
| tk->xtime_interval += interval; |
| tk->xtime_nsec -= offset; |
| tk->ntp_error -= (interval - offset) << tk->ntp_error_shift; |
| |
| 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. |
| */ |
| 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; |
| } |
| |
| } |
| |
| /** |
| * accumulate_nsecs_to_secs - Accumulates nsecs into secs |
| * |
| * Helper function that accumulates a the nsecs greater then 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 clock_set = 0; |
| |
| while (tk->xtime_nsec >= nsecps) { |
| int leap; |
| |
| tk->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 cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset, |
| u32 shift, |
| unsigned int *clock_set) |
| { |
| cycle_t interval = tk->cycle_interval << shift; |
| u64 raw_nsecs; |
| |
| /* If the offset is smaller then a shifted interval, do nothing */ |
| if (offset < interval) |
| return offset; |
| |
| /* Accumulate one shifted interval */ |
| offset -= interval; |
| tk->cycle_last += interval; |
| |
| tk->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 += ntp_tick_length() << 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 clocksource *clock; |
| struct timekeeper *real_tk = &tk_core.timekeeper; |
| struct timekeeper *tk = &shadow_timekeeper; |
| cycle_t 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; |
| |
| 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 |
| |
| /* Check if there's really nothing to do */ |
| if (offset < real_tk->cycle_interval) |
| goto out; |
| |
| /* |
| * 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 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 tk_core.seq against one before we start |
| * updating. |
| */ |
| memcpy(real_tk, tk, sizeof(*tk)); |
| timekeeping_update(real_tk, clock_set); |
| 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(); |
| } |
| |
| /** |
| * getboottime - Return the real time of system boot. |
| * @ts: pointer to the timespec to be set |
| * |
| * Returns the wall-time of boot in a timespec. |
| * |
| * 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) |
| { |
| struct timekeeper *tk = &tk_core.timekeeper; |
| ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot); |
| |
| *ts = ktime_to_timespec(t); |
| } |
| EXPORT_SYMBOL_GPL(getboottime); |
| |
| 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 timespec current_kernel_time(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 timespec64_to_timespec(now); |
| } |
| EXPORT_SYMBOL(current_kernel_time); |
| |
| struct timespec get_monotonic_coarse(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 timespec64_to_timespec(now); |
| } |
| |
| /* |
| * Must hold jiffies_lock |
| */ |
| void do_timer(unsigned long ticks) |
| { |
| jiffies_64 += ticks; |
| calc_global_load(ticks); |
| } |
| |
| /** |
| * ktime_get_update_offsets_tick - hrtimer helper |
| * @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 monotonic time at last tick and various offsets |
| */ |
| ktime_t ktime_get_update_offsets_tick(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->base_mono; |
| nsecs = tk->xtime_nsec >> tk->shift; |
| |
| *offs_real = tk->offs_real; |
| *offs_boot = tk->offs_boot; |
| *offs_tai = tk->offs_tai; |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return ktime_add_ns(base, nsecs); |
| } |
| |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| /** |
| * ktime_get_update_offsets_now - hrtimer helper |
| * @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 |
| * Called from hrtimer_interrupt() or retrigger_next_event() |
| */ |
| ktime_t ktime_get_update_offsets_now(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->base_mono; |
| nsecs = timekeeping_get_ns(tk); |
| |
| *offs_real = tk->offs_real; |
| *offs_boot = tk->offs_boot; |
| *offs_tai = tk->offs_tai; |
| } while (read_seqcount_retry(&tk_core.seq, seq)); |
| |
| return ktime_add_ns(base, nsecs); |
| } |
| #endif |
| |
| /** |
| * 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); |
| } |
| 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 timespec *phase_ts, const struct timespec *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(); |
| } |