diff options
| author | Thomas Gleixner | 2020-12-09 14:09:27 +0800 |
|---|---|---|
| committer | Marc Zyngier | 2021-04-07 16:33:20 +0100 |
| commit | b2c67cbe9f447312f5cdd7c6641b463f2349aec0 (patch) | |
| tree | 3df86da966a25b85da7c84cb893edb2705ccd720 /kernel | |
| parent | a8cf291bdac5d415eadb55e79df1fca8c3f0dfef (diff) | |
time: Add mechanism to recognize clocksource in time_get_snapshot
System time snapshots are not conveying information about the current
clocksource which was used, but callers like the PTP KVM guest
implementation have the requirement to evaluate the clocksource type to
select the appropriate mechanism.
Introduce a clocksource id field in struct clocksource which is by default
set to CSID_GENERIC (0). Clocksource implementations can set that field to
a value which allows to identify the clocksource.
Store the clocksource id of the current clocksource in the
system_time_snapshot so callers can evaluate which clocksource was used to
take the snapshot and act accordingly.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201209060932.212364-5-jianyong.wu@arm.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/clocksource.c | 2 | ||||
| -rw-r--r-- | kernel/time/timekeeping.c | 1 |
2 files changed, 3 insertions, 0 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index cce484a2cc7c..4fe1df894ee5 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -920,6 +920,8 @@ int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) clocksource_arch_init(cs); + if (WARN_ON_ONCE((unsigned int)cs->id >= CSID_MAX)) + cs->id = CSID_GENERIC; if (cs->vdso_clock_mode < 0 || cs->vdso_clock_mode >= VDSO_CLOCKMODE_MAX) { pr_warn("clocksource %s registered with invalid VDSO mode %d. Disabling VDSO support.\n", diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 6aee5768c86f..06f55f9258bf 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1048,6 +1048,7 @@ void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot) do { seq = read_seqcount_begin(&tk_core.seq); now = tk_clock_read(&tk->tkr_mono); + systime_snapshot->cs_id = tk->tkr_mono.clock->id; systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq; systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq; base_real = ktime_add(tk->tkr_mono.base, |