linux/kernel/time/timekeeping.c
Linus Torvalds 02201e3f1b Minor merge needed, due to function move.
Main excitement here is Peter Zijlstra's lockless rbtree optimization to
 speed module address lookup.  He found some abusers of the module lock
 doing that too.
 
 A little bit of parameter work here too; including Dan Streetman's breaking
 up the big param mutex so writing a parameter can load another module (yeah,
 really).  Unfortunately that broke the usual suspects, !CONFIG_MODULES and
 !CONFIG_SYSFS, so those fixes were appended too.
 
 Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Main excitement here is Peter Zijlstra's lockless rbtree optimization
  to speed module address lookup.  He found some abusers of the module
  lock doing that too.

  A little bit of parameter work here too; including Dan Streetman's
  breaking up the big param mutex so writing a parameter can load
  another module (yeah, really).  Unfortunately that broke the usual
  suspects, !CONFIG_MODULES and !CONFIG_SYSFS, so those fixes were
  appended too"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (26 commits)
  modules: only use mod->param_lock if CONFIG_MODULES
  param: fix module param locks when !CONFIG_SYSFS.
  rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()
  module: add per-module param_lock
  module: make perm const
  params: suppress unused variable error, warn once just in case code changes.
  modules: clarify CONFIG_MODULE_COMPRESS help, suggest 'N'.
  kernel/module.c: avoid ifdefs for sig_enforce declaration
  kernel/workqueue.c: remove ifdefs over wq_power_efficient
  kernel/params.c: export param_ops_bool_enable_only
  kernel/params.c: generalize bool_enable_only
  kernel/module.c: use generic module param operaters for sig_enforce
  kernel/params: constify struct kernel_param_ops uses
  sysfs: tightened sysfs permission checks
  module: Rework module_addr_{min,max}
  module: Use __module_address() for module_address_lookup()
  module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING
  module: Optimize __module_address() using a latched RB-tree
  rbtree: Implement generic latch_tree
  seqlock: Introduce raw_read_seqcount_latch()
  ...
2015-07-01 10:49:25 -07:00

2049 lines
55 KiB
C

/*
* 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;
/**
* 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.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);
}
#ifdef CONFIG_DEBUG_TIMEKEEPING
#define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
static void timekeeping_check_update(struct timekeeper *tk, cycle_t offset)
{
cycle_t 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 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 cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
{
struct timekeeper *tk = &tk_core.timekeeper;
cycle_t 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, cycle_t offset)
{
}
static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
{
cycle_t 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)
{
cycle_t interval;
u64 tmp, ntpinterval;
struct clocksource *old_clock;
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 = (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->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 s64 timekeeping_get_ns(struct tk_read_base *tkr)
{
cycle_t delta;
s64 nsec;
delta = timekeeping_get_delta(tkr);
nsec = delta * tkr->mult + tkr->xtime_nsec;
nsec >>= tkr->shift;
/* If arch requires, add in get_arch_timeoffset() */
return nsec + arch_gettimeoffset();
}
/**
* 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) + timekeeping_get_ns(tkr);
} 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);
/* Suspend-time cycles value for halted fast timekeeper. */
static cycle_t cycles_at_suspend;
static cycle_t 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);
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.tv64 != 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;
cycle_t cycle_now, delta;
s64 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;
s64 nsecs = 0;
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;
s64 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];
s64 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;
s64 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;
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->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);
#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(&tk->tkr_raw);
nsecs_real = timekeeping_get_ns(&tk->tkr_mono);
} 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_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;
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;
tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
tk_set_xtime(tk, ts);
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_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 ((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->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;
s64 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);
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;
cycle_t cycle_now, cycle_delta;
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 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;
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;
s64 tick_error;
bool negative;
u32 adj;
/* 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);
/* Sort out the magnitude of the correction */
tick_error = abs(tick_error);
for (adj = 0; tick_error > interval; adj++)
tick_error >>= 1;
/* scale the corrections */
timekeeping_apply_adjustment(tk, offset, negative, adj);
}
/*
* 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 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->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 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->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;
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;
#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 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 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;
}
/*
* 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.tv64 >= tk->next_leap_ktime.tv64))
*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 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();
}