diff options
Diffstat (limited to 'kernel/time/timekeeping.c')
| -rw-r--r-- | kernel/time/timekeeping.c | 90 |
1 files changed, 51 insertions, 39 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 37dec7e3db43..da233cdf89b0 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -258,10 +258,9 @@ static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock) tk->cycle_interval = interval; /* Go back from cycles -> shifted ns */ - tk->xtime_interval = (u64) interval * clock->mult; + tk->xtime_interval = interval * clock->mult; tk->xtime_remainder = ntpinterval - tk->xtime_interval; - tk->raw_interval = - ((u64) interval * clock->mult) >> clock->shift; + tk->raw_interval = (interval * clock->mult) >> clock->shift; /* if changing clocks, convert xtime_nsec shift units */ if (old_clock) { @@ -299,10 +298,10 @@ u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset; static inline u32 arch_gettimeoffset(void) { return 0; } #endif -static inline s64 timekeeping_delta_to_ns(struct tk_read_base *tkr, +static inline u64 timekeeping_delta_to_ns(struct tk_read_base *tkr, cycle_t delta) { - s64 nsec; + u64 nsec; nsec = delta * tkr->mult + tkr->xtime_nsec; nsec >>= tkr->shift; @@ -311,7 +310,7 @@ static inline s64 timekeeping_delta_to_ns(struct tk_read_base *tkr, return nsec + arch_gettimeoffset(); } -static inline s64 timekeeping_get_ns(struct tk_read_base *tkr) +static inline u64 timekeeping_get_ns(struct tk_read_base *tkr) { cycle_t delta; @@ -319,8 +318,8 @@ static inline s64 timekeeping_get_ns(struct tk_read_base *tkr) return timekeeping_delta_to_ns(tkr, delta); } -static inline s64 timekeeping_cycles_to_ns(struct tk_read_base *tkr, - cycle_t cycles) +static inline u64 timekeeping_cycles_to_ns(struct tk_read_base *tkr, + cycle_t cycles) { cycle_t delta; @@ -425,6 +424,35 @@ u64 ktime_get_raw_fast_ns(void) } 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 cycle_t cycles_at_suspend; @@ -623,7 +651,7 @@ static void timekeeping_forward_now(struct timekeeper *tk) { struct clocksource *clock = tk->tkr_mono.clock; cycle_t cycle_now, delta; - s64 nsec; + u64 nsec; cycle_now = tk->tkr_mono.read(clock); delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask); @@ -652,7 +680,7 @@ int __getnstimeofday64(struct timespec64 *ts) { struct timekeeper *tk = &tk_core.timekeeper; unsigned long seq; - s64 nsecs = 0; + u64 nsecs; do { seq = read_seqcount_begin(&tk_core.seq); @@ -692,7 +720,7 @@ ktime_t ktime_get(void) struct timekeeper *tk = &tk_core.timekeeper; unsigned int seq; ktime_t base; - s64 nsecs; + u64 nsecs; WARN_ON(timekeeping_suspended); @@ -735,7 +763,7 @@ 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; + u64 nsecs; WARN_ON(timekeeping_suspended); @@ -779,7 +807,7 @@ ktime_t ktime_get_raw(void) struct timekeeper *tk = &tk_core.timekeeper; unsigned int seq; ktime_t base; - s64 nsecs; + u64 nsecs; do { seq = read_seqcount_begin(&tk_core.seq); @@ -804,8 +832,8 @@ void ktime_get_ts64(struct timespec64 *ts) { struct timekeeper *tk = &tk_core.timekeeper; struct timespec64 tomono; - s64 nsec; unsigned int seq; + u64 nsec; WARN_ON(timekeeping_suspended); @@ -893,8 +921,8 @@ void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot) unsigned long seq; ktime_t base_raw; ktime_t base_real; - s64 nsec_raw; - s64 nsec_real; + u64 nsec_raw; + u64 nsec_real; cycle_t now; WARN_ON_ONCE(timekeeping_suspended); @@ -1052,7 +1080,7 @@ int get_device_system_crosststamp(int (*get_time_fn) cycle_t cycles, now, interval_start; unsigned int clock_was_set_seq = 0; ktime_t base_real, base_raw; - s64 nsec_real, nsec_raw; + u64 nsec_real, nsec_raw; u8 cs_was_changed_seq; unsigned long seq; bool do_interp; @@ -1365,7 +1393,7 @@ void getrawmonotonic64(struct timespec64 *ts) struct timekeeper *tk = &tk_core.timekeeper; struct timespec64 ts64; unsigned long seq; - s64 nsecs; + u64 nsecs; do { seq = read_seqcount_begin(&tk_core.seq); @@ -1616,7 +1644,7 @@ void timekeeping_resume(void) struct clocksource *clock = tk->tkr_mono.clock; unsigned long flags; struct timespec64 ts_new, ts_delta; - cycle_t cycle_now, cycle_delta; + cycle_t cycle_now; sleeptime_injected = false; read_persistent_clock64(&ts_new); @@ -1642,27 +1670,11 @@ void timekeeping_resume(void) cycle_now = tk->tkr_mono.read(clock); if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) && cycle_now > tk->tkr_mono.cycle_last) { - u64 num, max = ULLONG_MAX; - u32 mult = clock->mult; - u32 shift = clock->shift; - s64 nsec = 0; - - cycle_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, - tk->tkr_mono.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; + 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) { |