[patch V2 11/26] timekeeping: Add clock_valid flag to timekeeper

From: Thomas Gleixner
Date: Mon May 19 2025 - 04:38:01 EST


From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

In preparation for supporting independent auxiliary timekeepers, add a
clock valid field and set it to true for the system timekeeper.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
include/linux/timekeeper_internal.h | 2 ++
kernel/time/timekeeping.c | 5 +++--
2 files changed, 5 insertions(+), 2 deletions(-)
---
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -73,6 +73,7 @@ struct tk_read_base {
* @raw_sec: CLOCK_MONOTONIC_RAW time in seconds
* @clock_was_set_seq: The sequence number of clock was set events
* @cs_was_changed_seq: The sequence number of clocksource change events
+ * @clock_valid: Indicator for valid clock
* @monotonic_to_boot: CLOCK_MONOTONIC to CLOCK_BOOTTIME offset
* @cycle_interval: Number of clock cycles in one NTP interval
* @xtime_interval: Number of clock shifted nano seconds in one NTP
@@ -149,6 +150,7 @@ struct timekeeper {
/* Cachline 3 and 4 (timekeeping internal variables): */
unsigned int clock_was_set_seq;
u8 cs_was_changed_seq;
+ u8 clock_valid;

struct timespec64 monotonic_to_boot;

--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1665,11 +1665,12 @@ read_persistent_wall_and_boot_offset(str
*boot_offset = ns_to_timespec64(local_clock());
}

-static __init void tkd_basic_setup(struct tk_data *tkd, enum timekeeper_ids tk_id)
+static __init void tkd_basic_setup(struct tk_data *tkd, enum timekeeper_ids tk_id, bool valid)
{
raw_spin_lock_init(&tkd->lock);
seqcount_raw_spinlock_init(&tkd->seq, &tkd->lock);
tkd->timekeeper.id = tkd->shadow_timekeeper.id = tk_id;
+ tkd->timekeeper.clock_valid = tkd->shadow_timekeeper.clock_valid = valid;
}

/*
@@ -1699,7 +1700,7 @@ void __init timekeeping_init(void)
struct timekeeper *tks = &tk_core.shadow_timekeeper;
struct clocksource *clock;

- tkd_basic_setup(&tk_core, TIMEKEEPER_CORE);
+ tkd_basic_setup(&tk_core, TIMEKEEPER_CORE, true);

read_persistent_wall_and_boot_offset(&wall_time, &boot_offset);
if (timespec64_valid_settod(&wall_time) &&