linux/kernel/time
Linus Torvalds 2d6d57f889 Updates for NTP/timekeeping and PTP:
- Expand timekeeping snapshot mechanisms
 
     The various snapshot functions are mostly used for PTP to collect
     "atomic" snapshots of various involved clocks.
 
     They lack support for the recently introduced AUX clocks and do not
     provide the underlying counter value (e.g. TSC) to user space. Exposing
     the counter value snapshot allows for better control and steering.
 
     Convert the hard wired ktime_get_snapshot() to take a clock ID, which
     allows the caller to select the clock ID to be captured along with
     CLOCK_MONONOTONIC_RAW. Additionally capture the underlying hardware
     counter value and the clock source ID of the counter.
 
     Expand the hardware based snapshot capture where devices provide a
     mechanism to snapshot the hardware PTP clock and the system counter
     (usually via PCI/PTM) to support AUX clocks and also provide the
     captured counter value back to the caller and not only the clock
     timestamps derived from it.
 
   - Add a new optional read_snapshot() callback to clocksources
 
     That is required to capture atomic snapshots from clocksources which
     are derived from TSC with a scaling mechanism (e.g. Hyper-V, KVMclock).
 
     The value pair is handed back in the snapshot structure to the callers,
     so they can do the necessary correlations in a more precise way.
 
 This touches usage sites of the affected functions and data structure all
 over the tree, but stays fully backwards compatible for the existing user
 space exposed interfaces. New PTP IOCTLs will provide access to the
 extended functionality in later kernel versions.
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Merge tag 'timers-ptp-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip

Pull timekeeping updates from Thomas Gleixner:
 "Updates for NTP/timekeeping and PTP:

   - Expand timekeeping snapshot mechanisms

     The various snapshot functions are mostly used for PTP to collect
     "atomic" snapshots of various involved clocks.

     They lack support for the recently introduced AUX clocks and do not
     provide the underlying counter value (e.g. TSC) to user space.
     Exposing the counter value snapshot allows for better control and
     steering.

     Convert the hard wired ktime_get_snapshot() to take a clock ID,
     which allows the caller to select the clock ID to be captured along
     with CLOCK_MONONOTONIC_RAW. Additionally capture the underlying
     hardware counter value and the clock source ID of the counter.

     Expand the hardware based snapshot capture where devices provide a
     mechanism to snapshot the hardware PTP clock and the system counter
     (usually via PCI/PTM) to support AUX clocks and also provide the
     captured counter value back to the caller and not only the clock
     timestamps derived from it.

   - Add a new optional read_snapshot() callback to clocksources

     That is required to capture atomic snapshots from clocksources
     which are derived from TSC with a scaling mechanism (e.g. Hyper-V,
     KVMclock).

     The value pair is handed back in the snapshot structure to the
     callers, so they can do the necessary correlations in a more
     precise way.

  This touches usage sites of the affected functions and data structure
  all over the tree, but stays fully backwards compatible for the
  existing user space exposed interfaces. New PTP IOCTLs will provide
  access to the extended functionality in later kernel versions"

* tag 'timers-ptp-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (28 commits)
  ptp: vmclock: Use hw_cycles from snapshot for precise TSC pairing
  x86/kvmclock: Implement read_snapshot() for kvmclock clocksource
  clocksource/hyperv: Implement read_snapshot() for TSC page clocksource
  timekeeping: Add clocksource read_snapshot() method and hw_cycles to snapshot
  ptp: Switch to ktime_get_snapshot_id() for pre/post timestamps
  timekeeping: Add support for AUX clock cross timestamping
  timekeeping: Remove system_device_crosststamp::sys_realtime
  ALSA: hda/common: Use system_device_crosststamp::sys_systime
  wifi: iwlwifi: Use system_device_crosststamp::sys_systime
  ptp: Use system_device_crosststamp::sys_systime
  timekeeping: Prepare for cross timestamps on arbitrary clock IDs
  timekeeping: Remove ktime_get_snapshot()
  virtio_rtc: Use provided clock ID for history snapshot
  net/mlx5: Use provided clock ID for history snapshot
  igc: Use provided clock ID for history snapshot
  ice/ptp: Use provided clock ID for history snapshot
  wifi: iwlwifi: Adopt PTP cross timestamps to core changes
  timekeeping: Add CLOCK ID to system_device_crosststamp
  timekeeping: Add system_counterval_t to struct system_device_crosststamp
  timekeeping: Add CLOCK_AUX support for ktime_get_snapshot_id()
  ...
2026-06-15 13:51:27 +05:30
..
.kunitconfig time/kunit: Add .kunitconfig 2026-02-24 08:41:51 +01:00
alarmtimer.c alarmtimer: Remove stale return description from alarm_handle_timer() 2026-05-06 08:33:08 +02:00
clockevents.c clockevents: Fix duplicate type specifier in stub function parameter 2026-06-02 21:07:55 +02:00
clocksource-wdtest.c clocksource: Rewrite watchdog code completely 2026-03-20 13:36:32 +01:00
clocksource.c Updates for the time/timer core subsystem: 2026-06-15 13:39:12 +05:30
hrtimer.c hrtimer: Fix the bogus return type of __hrtimer_start_range_ns() 2026-05-13 22:41:12 +02:00
itimer.c
jiffies.c time/jiffies: Register jiffies clocksource before usage 2026-06-13 15:22:40 +02:00
Kconfig Update to the VDSO subsystem: 2026-04-14 10:53:44 -07:00
Makefile timens: Remove dependency on the vDSO 2026-03-26 15:44:23 +01:00
namespace_internal.h timens: Remove dependency on the vDSO 2026-03-26 15:44:23 +01:00
namespace_vdso.c mm.git review status for linus..mm-stable 2026-04-15 12:59:16 -07:00
namespace.c time/namespace: Export init_time_ns and do_timens_ktime_to_host() 2026-06-02 21:05:36 +02:00
ntp_internal.h
ntp.c
posix-clock.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
posix-cpu-timers.c posix-cpu-timers: Fix pid refcount leak in do_cpu_nanosleep() error path 2026-06-13 16:16:02 +02:00
posix-stubs.c
posix-timers.c posix-timers: Switch to hrtimer_start_expires_user() 2026-05-01 21:36:12 +02:00
posix-timers.h posix-timers: Expand timer_[re]arm() callbacks with a boolean return value 2026-05-01 21:36:11 +02:00
sched_clock.c time/sched_clock: Use ACCESS_PRIVATE() to evaluate hrtimer::function 2026-01-13 18:08:57 +01:00
sleep_timeout.c
test_udelay.c
tick-broadcast-hrtimer.c clockevents: Remove redundant CLOCK_EVT_FEAT_KTIME 2026-02-27 16:40:06 +01:00
tick-broadcast.c clockevents: Add missing resets of the next_event_forced flag 2026-04-16 21:22:04 +02:00
tick-common.c clockevents: Prevent timer interrupt starvation 2026-04-10 22:45:38 +02:00
tick-internal.h cpufreq: ondemand: Simplify idle cputime granularity test 2026-01-28 22:24:58 +01:00
tick-legacy.c
tick-oneshot.c treewide: Update email address 2026-01-11 06:09:11 -10:00
tick-sched.c Updates for the NOHZ subsystem: 2026-06-15 13:48:52 +05:30
tick-sched.h tick/sched: Remove unused fields 2026-06-02 21:27:25 +02:00
time_test.c time/kunit: Document handling of negative years of is_leap() 2026-02-02 12:37:54 +01:00
time.c time: Fix off-by-one in settimeofday() usec validation 2026-06-02 21:07:55 +02:00
timeconst.bc
timeconv.c
timecounter.c time/timecounter: Inline timecounter_cyc2time() 2025-12-15 20:16:49 +01:00
timekeeping_debug.c
timekeeping_internal.h
timekeeping.c timekeeping: Add clocksource read_snapshot() method and hw_cycles to snapshot 2026-06-04 11:04:18 +02:00
timekeeping.h timekeeping: Provide infrastructure for coupled clockevents 2026-02-27 16:40:08 +01:00
timer_list.c tick/sched: Remove unused fields 2026-06-02 21:27:25 +02:00
timer_migration.c Updates for the time/timer core subsystem: 2026-06-15 13:39:12 +05:30
timer_migration.h timers/migration: Turn tmigr_hierarchy level_list into a flexible array 2026-06-02 21:34:03 +02:00
timer.c hrtimer: Return ktime_t from hrtimer_get_next_event()/hrtimer_next_event_without() 2026-05-06 08:33:09 +02:00
vsyscall.c