Expose the auxiliary clock data so it can be read from the vDSO.

Architectures not using the generic vDSO time framework,
namely SPARC64, are not supported.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 include/linux/timekeeper_internal.h | 13 ++++++++++++
 include/vdso/datapage.h             |  3 +++
 kernel/time/namespace.c             |  5 +++++
 kernel/time/timekeeping.c           | 12 +++++++++++
 kernel/time/vsyscall.c              | 40 +++++++++++++++++++++++++++++++++++++
 5 files changed, 73 insertions(+)

diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
index ca79938b62f396afd503e0cf06bbecf6f95cfce4..5de2e019399c72246f7d7dfad561c8b3d479dbd1 100644
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -190,4 +190,17 @@ static inline void update_vsyscall_tz(void)
 }
 #endif
 
+#if defined(CONFIG_GENERIC_TIME_VSYSCALL) && defined(CONFIG_GENERIC_GETTIMEOFDAY) && \
+	defined(CONFIG_POSIX_AUX_CLOCKS)
+
+extern void vdso_time_update_aux(struct timekeeper *tk);
+
+#else
+
+static inline void vdso_time_update_aux(struct timekeeper *tk)
+{
+}
+
+#endif /* CONFIG_GENERIC_TIME_VSYSCALL && CONFIG_POSIX_AUX_CLOCKS */
+
 #endif /* _LINUX_TIMEKEEPER_INTERNAL_H */
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
index 1864e76e8f691bab10813543880f71bc59afa9c0..f4c96d9ce674abb07ccd8703f1a04da7631c1677 100644
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h
@@ -38,6 +38,7 @@ struct vdso_arch_data {
 #endif
 
 #define VDSO_BASES	(CLOCK_TAI + 1)
+#define VDSO_BASE_AUX	0
 #define VDSO_HRES	(BIT(CLOCK_REALTIME)		| \
 			 BIT(CLOCK_MONOTONIC)		| \
 			 BIT(CLOCK_BOOTTIME)		| \
@@ -117,6 +118,7 @@ struct vdso_clock {
  * @arch_data:		architecture specific data (optional, defaults
  *			to an empty struct)
  * @clock_data:		clocksource related data (array)
+ * @aux_clock_data:	auxiliary clocksource related data (array)
  * @tz_minuteswest:	minutes west of Greenwich
  * @tz_dsttime:		type of DST correction
  * @hrtimer_res:	hrtimer resolution
@@ -133,6 +135,7 @@ struct vdso_time_data {
 	struct arch_vdso_time_data	arch_data;
 
 	struct vdso_clock		clock_data[CS_BASES];
+	struct vdso_clock		aux_clock_data[MAX_AUX_CLOCKS];
 
 	s32				tz_minuteswest;
 	s32				tz_dsttime;
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index e3642278df433c41654ffb6a8043c3fcecc2994a..667452768ed3b50e48e3cfb70f8ef68e4bed9e0b 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -242,6 +242,11 @@ static void timens_set_vvar_page(struct task_struct *task,
 	for (i = 0; i < CS_BASES; i++)
 		timens_setup_vdso_clock_data(&vc[i], ns);
 
+	if (IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS)) {
+		for (i = 0; i < ARRAY_SIZE(vdata->aux_clock_data); i++)
+			timens_setup_vdso_clock_data(&vdata->aux_clock_data[i], ns);
+	}
+
 out:
 	mutex_unlock(&offset_lock);
 }
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 6a088378df54d561ecfeafb45a8b54333e11a9a7..928b8e0773f9e1b8fd700f130a700c5908fe6c27 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -66,11 +66,21 @@ static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)
 {
 	return ktime_get_aux_ts64(CLOCK_AUX + tkid - TIMEKEEPER_AUX_FIRST, ts);
 }
+
+static inline bool tk_is_aux(const struct timekeeper *tk)
+{
+	return tk->id >= TIMEKEEPER_AUX_FIRST && tk->id <= TIMEKEEPER_AUX_LAST;
+}
 #else
 static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)
 {
 	return false;
 }
+
+static inline bool tk_is_aux(const struct timekeeper *tk)
+{
+	return false;
+}
 #endif
 
 /* flag for if timekeeping is suspended */
@@ -719,6 +729,8 @@ static void timekeeping_update_from_shadow(struct tk_data *tkd, unsigned int act
 
 		update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
 		update_fast_timekeeper(&tk->tkr_raw,  &tk_fast_raw);
+	} else if (tk_is_aux(tk)) {
+		vdso_time_update_aux(tk);
 	}
 
 	if (action & TK_CLOCK_WAS_SET)
diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
index df6bada2d58ed9a03e5dd3cb4b218983089a2877..62d9701db9135ba4ef377f3f534a9279d7922d2d 100644
--- a/kernel/time/vsyscall.c
+++ b/kernel/time/vsyscall.c
@@ -136,6 +136,46 @@ void update_vsyscall_tz(void)
 	__arch_sync_vdso_time_data(vdata);
 }
 
+#ifdef CONFIG_POSIX_AUX_CLOCKS
+void vdso_time_update_aux(struct timekeeper *tk)
+{
+	struct vdso_time_data *vdata = vdso_k_time_data;
+	struct vdso_timestamp *vdso_ts;
+	struct vdso_clock *vc;
+	s32 clock_mode;
+	u64 nsec;
+
+	vc = &vdata->aux_clock_data[tk->id - TIMEKEEPER_AUX_FIRST];
+	vdso_ts = &vc->basetime[VDSO_BASE_AUX];
+	clock_mode = tk->tkr_mono.clock->vdso_clock_mode;
+	if (!tk->clock_valid)
+		clock_mode = VDSO_CLOCKMODE_NONE;
+
+	/* copy vsyscall data */
+	vdso_write_begin_clock(vc, true);
+
+	vc->clock_mode = clock_mode;
+
+	if (clock_mode != VDSO_CLOCKMODE_NONE) {
+		fill_clock_configuration(vc, &tk->tkr_mono);
+
+		vdso_ts->sec	= tk->xtime_sec;
+
+		nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
+		nsec += tk->offs_aux;
+		vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec);
+		nsec = nsec << tk->tkr_mono.shift;
+		vdso_ts->nsec = nsec;
+	}
+
+	__arch_update_vdso_clock(vc);
+
+	vdso_write_end_clock(vc, true);
+
+	__arch_sync_vdso_time_data(vdata);
+}
+#endif
+
 /**
  * vdso_update_begin - Start of a VDSO update section
  *

-- 
2.50.0

On Tue, Jul 01 2025 at 10:58, Thomas Weißschuh wrote:
>  
> +#if defined(CONFIG_GENERIC_TIME_VSYSCALL) && defined(CONFIG_GENERIC_GETTIMEOFDAY) && \
> +	defined(CONFIG_POSIX_AUX_CLOCKS)

CONFIG_GENERIC_GETTIMEOFDAY requires CONFIG_GENERIC_TIME_VSYSCALL, but
that's not expressed anywhere. This stuff has grown too many config
options over time:

GENERIC_TIME_VSYSCALL, HAVE_GENERIC_VDSO, GENERIC_VDSO_DATA_STORE

All architectures except SPARC64 use the generic code and the generic
VDSO data store implementation. That config maze wants to be
consolidated.

On Mon, Jul 7, 2025, at 08:57, Thomas Gleixner wrote:
> On Tue, Jul 01 2025 at 10:58, Thomas Weißschuh wrote:
>>  
>> +#if defined(CONFIG_GENERIC_TIME_VSYSCALL) && defined(CONFIG_GENERIC_GETTIMEOFDAY) && \
>> +	defined(CONFIG_POSIX_AUX_CLOCKS)
>
> CONFIG_GENERIC_GETTIMEOFDAY requires CONFIG_GENERIC_TIME_VSYSCALL, but
> that's not expressed anywhere. This stuff has grown too many config
> options over time:
>
> GENERIC_TIME_VSYSCALL, HAVE_GENERIC_VDSO, GENERIC_VDSO_DATA_STORE
>
> All architectures except SPARC64 use the generic code and the generic
> VDSO data store implementation. That config maze wants to be
> consolidated.

Would it help to replace the custom sparc64 vdso with the
thing that parisc does and call the fallback directly?

I doubt anyone still cares about the clock_gettime() performance
on sparc64, and removing it would remove all those special cases:

 arch/sparc/Kconfig                  |   1 -
 arch/sparc/include/asm/vvar.h       |  75 --------
 arch/sparc/kernel/Makefile          |   1 -
 arch/sparc/kernel/vdso.c            |  69 --------
 arch/sparc/vdso/Makefile            |   2 +-
 arch/sparc/vdso/vclock_gettime.c    | 340 +++---------------------------------
 arch/sparc/vdso/vdso.lds.S          |   2 -
 arch/sparc/vdso/vdso32/vdso32.lds.S |   3 +-
 arch/sparc/vdso/vma.c               | 265 +---------------------------
 9 files changed, 28 insertions(+), 730 deletions(-)

(the added lines here also fix the missing clock_gettime64,
which was equally blocked on the sparc64 oddities)

      Arnd

On Mon, Jul 07 2025 at 13:34, Arnd Bergmann wrote:
> On Mon, Jul 7, 2025, at 08:57, Thomas Gleixner wrote:
>> On Tue, Jul 01 2025 at 10:58, Thomas Weißschuh wrote:
>>>  
>>> +#if defined(CONFIG_GENERIC_TIME_VSYSCALL) && defined(CONFIG_GENERIC_GETTIMEOFDAY) && \
>>> +	defined(CONFIG_POSIX_AUX_CLOCKS)
>>
>> CONFIG_GENERIC_GETTIMEOFDAY requires CONFIG_GENERIC_TIME_VSYSCALL, but
>> that's not expressed anywhere. This stuff has grown too many config
>> options over time:
>>
>> GENERIC_TIME_VSYSCALL, HAVE_GENERIC_VDSO, GENERIC_VDSO_DATA_STORE
>>
>> All architectures except SPARC64 use the generic code and the generic
>> VDSO data store implementation. That config maze wants to be
>> consolidated.
>
> Would it help to replace the custom sparc64 vdso with the
> thing that parisc does and call the fallback directly?

Definitely.

> I doubt anyone still cares about the clock_gettime() performance
> on sparc64, and removing it would remove all those special cases:
>
>  arch/sparc/Kconfig                  |   1 -
>  arch/sparc/include/asm/vvar.h       |  75 --------
>  arch/sparc/kernel/Makefile          |   1 -
>  arch/sparc/kernel/vdso.c            |  69 --------
>  arch/sparc/vdso/Makefile            |   2 +-
>  arch/sparc/vdso/vclock_gettime.c    | 340 +++---------------------------------
>  arch/sparc/vdso/vdso.lds.S          |   2 -
>  arch/sparc/vdso/vdso32/vdso32.lds.S |   3 +-
>  arch/sparc/vdso/vma.c               | 265 +---------------------------
>  9 files changed, 28 insertions(+), 730 deletions(-)

That's definitely an argument :)

> (the added lines here also fix the missing clock_gettime64,
> which was equally blocked on the sparc64 oddities)

I'm all for it.

Can you post a patch to that effect?

Thanks,

        tglx

On Mon, Jul 7, 2025, at 15:16, Thomas Gleixner wrote:
> On Mon, Jul 07 2025 at 13:34, Arnd Bergmann wrote:
>> On Mon, Jul 7, 2025, at 08:57, Thomas Gleixner wrote:

>> (the added lines here also fix the missing clock_gettime64,
>> which was equally blocked on the sparc64 oddities)
>
> I'm all for it.
>
> Can you post a patch to that effect?
>

Sent, plus a bonus patch to remove CONFIG_ARCH_CLOCKSOURCE_DATA.

      Arnd

The following commit has been merged into the timers/ptp branch of tip:

Commit-ID:     380b84e168e57c54d0a9e053a5558fddc43f0c1a
Gitweb:        https://git.kernel.org/tip/380b84e168e57c54d0a9e053a5558fddc43f0c1a
Author:        Thomas Weißschuh <thomas.weissschuh@linutronix.de>
AuthorDate:    Tue, 01 Jul 2025 10:58:05 +02:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Fri, 18 Jul 2025 13:45:33 +02:00

vdso/vsyscall: Update auxiliary clock data in the datapage

Expose the auxiliary clock data so it can be read from the vDSO.

Architectures not using the generic vDSO time framework,
namely SPARC64, are not supported.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250701-vdso-auxclock-v1-11-df7d9f87b9b8@linutronix.de

---
 include/linux/timekeeper_internal.h |  6 ++++-
 include/vdso/datapage.h             |  3 ++-
 kernel/time/namespace.c             |  5 ++++-
 kernel/time/timekeeping.c           | 12 ++++++++-
 kernel/time/vsyscall.c              | 40 ++++++++++++++++++++++++++++-
 5 files changed, 66 insertions(+)

diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
index ca79938..c27aac6 100644
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -190,4 +190,10 @@ static inline void update_vsyscall_tz(void)
 }
 #endif
 
+#if defined(CONFIG_GENERIC_GETTIMEOFDAY) && defined(CONFIG_POSIX_AUX_CLOCKS)
+extern void vdso_time_update_aux(struct timekeeper *tk);
+#else
+static inline void vdso_time_update_aux(struct timekeeper *tk) { }
+#endif
+
 #endif /* _LINUX_TIMEKEEPER_INTERNAL_H */
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
index 1864e76..f4c96d9 100644
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h
@@ -38,6 +38,7 @@ struct vdso_arch_data {
 #endif
 
 #define VDSO_BASES	(CLOCK_TAI + 1)
+#define VDSO_BASE_AUX	0
 #define VDSO_HRES	(BIT(CLOCK_REALTIME)		| \
 			 BIT(CLOCK_MONOTONIC)		| \
 			 BIT(CLOCK_BOOTTIME)		| \
@@ -117,6 +118,7 @@ struct vdso_clock {
  * @arch_data:		architecture specific data (optional, defaults
  *			to an empty struct)
  * @clock_data:		clocksource related data (array)
+ * @aux_clock_data:	auxiliary clocksource related data (array)
  * @tz_minuteswest:	minutes west of Greenwich
  * @tz_dsttime:		type of DST correction
  * @hrtimer_res:	hrtimer resolution
@@ -133,6 +135,7 @@ struct vdso_time_data {
 	struct arch_vdso_time_data	arch_data;
 
 	struct vdso_clock		clock_data[CS_BASES];
+	struct vdso_clock		aux_clock_data[MAX_AUX_CLOCKS];
 
 	s32				tz_minuteswest;
 	s32				tz_dsttime;
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index e364227..6674527 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -242,6 +242,11 @@ static void timens_set_vvar_page(struct task_struct *task,
 	for (i = 0; i < CS_BASES; i++)
 		timens_setup_vdso_clock_data(&vc[i], ns);
 
+	if (IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS)) {
+		for (i = 0; i < ARRAY_SIZE(vdata->aux_clock_data); i++)
+			timens_setup_vdso_clock_data(&vdata->aux_clock_data[i], ns);
+	}
+
 out:
 	mutex_unlock(&offset_lock);
 }
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index cbcf090..243fe25 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -66,11 +66,21 @@ static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)
 {
 	return ktime_get_aux_ts64(CLOCK_AUX + tkid - TIMEKEEPER_AUX_FIRST, ts);
 }
+
+static inline bool tk_is_aux(const struct timekeeper *tk)
+{
+	return tk->id >= TIMEKEEPER_AUX_FIRST && tk->id <= TIMEKEEPER_AUX_LAST;
+}
 #else
 static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)
 {
 	return false;
 }
+
+static inline bool tk_is_aux(const struct timekeeper *tk)
+{
+	return false;
+}
 #endif
 
 /* flag for if timekeeping is suspended */
@@ -719,6 +729,8 @@ static void timekeeping_update_from_shadow(struct tk_data *tkd, unsigned int act
 
 		update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
 		update_fast_timekeeper(&tk->tkr_raw,  &tk_fast_raw);
+	} else if (tk_is_aux(tk)) {
+		vdso_time_update_aux(tk);
 	}
 
 	if (action & TK_CLOCK_WAS_SET)
diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
index df6bada..8ba8b0d 100644
--- a/kernel/time/vsyscall.c
+++ b/kernel/time/vsyscall.c
@@ -136,6 +136,46 @@ void update_vsyscall_tz(void)
 	__arch_sync_vdso_time_data(vdata);
 }
 
+#ifdef CONFIG_POSIX_AUX_CLOCKS
+void vdso_time_update_aux(struct timekeeper *tk)
+{
+	struct vdso_time_data *vdata = vdso_k_time_data;
+	struct vdso_timestamp *vdso_ts;
+	struct vdso_clock *vc;
+	s32 clock_mode;
+	u64 nsec;
+
+	vc = &vdata->aux_clock_data[tk->id - TIMEKEEPER_AUX_FIRST];
+	vdso_ts = &vc->basetime[VDSO_BASE_AUX];
+	clock_mode = tk->tkr_mono.clock->vdso_clock_mode;
+	if (!tk->clock_valid)
+		clock_mode = VDSO_CLOCKMODE_NONE;
+
+	/* copy vsyscall data */
+	vdso_write_begin_clock(vc);
+
+	vc->clock_mode = clock_mode;
+
+	if (clock_mode != VDSO_CLOCKMODE_NONE) {
+		fill_clock_configuration(vc, &tk->tkr_mono);
+
+		vdso_ts->sec	= tk->xtime_sec;
+
+		nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
+		nsec += tk->offs_aux;
+		vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec);
+		nsec = nsec << tk->tkr_mono.shift;
+		vdso_ts->nsec = nsec;
+	}
+
+	__arch_update_vdso_clock(vc);
+
+	vdso_write_end_clock(vc);
+
+	__arch_sync_vdso_time_data(vdata);
+}
+#endif
+
 /**
  * vdso_update_begin - Start of a VDSO update section
  *

The following commit has been merged into the timers/ptp branch of tip:

Commit-ID:     e0c8cdaf04a26206b96af0cc15947afd4cbb570c
Gitweb:        https://git.kernel.org/tip/e0c8cdaf04a26206b96af0cc15947afd4cbb570c
Author:        Thomas Weißschuh <thomas.weissschuh@linutronix.de>
AuthorDate:    Tue, 01 Jul 2025 10:58:05 +02:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 09 Jul 2025 11:52:35 +02:00

vdso/vsyscall: Update auxiliary clock data in the datapage

Expose the auxiliary clock data so it can be read from the vDSO.

Architectures not using the generic vDSO time framework,
namely SPARC64, are not supported.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250701-vdso-auxclock-v1-11-df7d9f87b9b8@linutronix.de

---
 include/linux/timekeeper_internal.h |  6 ++++-
 include/vdso/datapage.h             |  3 ++-
 kernel/time/namespace.c             |  5 ++++-
 kernel/time/timekeeping.c           | 12 ++++++++-
 kernel/time/vsyscall.c              | 40 ++++++++++++++++++++++++++++-
 5 files changed, 66 insertions(+)

diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
index ca79938..c27aac6 100644
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -190,4 +190,10 @@ static inline void update_vsyscall_tz(void)
 }
 #endif
 
+#if defined(CONFIG_GENERIC_GETTIMEOFDAY) && defined(CONFIG_POSIX_AUX_CLOCKS)
+extern void vdso_time_update_aux(struct timekeeper *tk);
+#else
+static inline void vdso_time_update_aux(struct timekeeper *tk) { }
+#endif
+
 #endif /* _LINUX_TIMEKEEPER_INTERNAL_H */
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
index 1864e76..f4c96d9 100644
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h
@@ -38,6 +38,7 @@ struct vdso_arch_data {
 #endif
 
 #define VDSO_BASES	(CLOCK_TAI + 1)
+#define VDSO_BASE_AUX	0
 #define VDSO_HRES	(BIT(CLOCK_REALTIME)		| \
 			 BIT(CLOCK_MONOTONIC)		| \
 			 BIT(CLOCK_BOOTTIME)		| \
@@ -117,6 +118,7 @@ struct vdso_clock {
  * @arch_data:		architecture specific data (optional, defaults
  *			to an empty struct)
  * @clock_data:		clocksource related data (array)
+ * @aux_clock_data:	auxiliary clocksource related data (array)
  * @tz_minuteswest:	minutes west of Greenwich
  * @tz_dsttime:		type of DST correction
  * @hrtimer_res:	hrtimer resolution
@@ -133,6 +135,7 @@ struct vdso_time_data {
 	struct arch_vdso_time_data	arch_data;
 
 	struct vdso_clock		clock_data[CS_BASES];
+	struct vdso_clock		aux_clock_data[MAX_AUX_CLOCKS];
 
 	s32				tz_minuteswest;
 	s32				tz_dsttime;
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index e364227..6674527 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -242,6 +242,11 @@ static void timens_set_vvar_page(struct task_struct *task,
 	for (i = 0; i < CS_BASES; i++)
 		timens_setup_vdso_clock_data(&vc[i], ns);
 
+	if (IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS)) {
+		for (i = 0; i < ARRAY_SIZE(vdata->aux_clock_data); i++)
+			timens_setup_vdso_clock_data(&vdata->aux_clock_data[i], ns);
+	}
+
 out:
 	mutex_unlock(&offset_lock);
 }
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index cbcf090..243fe25 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -66,11 +66,21 @@ static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)
 {
 	return ktime_get_aux_ts64(CLOCK_AUX + tkid - TIMEKEEPER_AUX_FIRST, ts);
 }
+
+static inline bool tk_is_aux(const struct timekeeper *tk)
+{
+	return tk->id >= TIMEKEEPER_AUX_FIRST && tk->id <= TIMEKEEPER_AUX_LAST;
+}
 #else
 static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)
 {
 	return false;
 }
+
+static inline bool tk_is_aux(const struct timekeeper *tk)
+{
+	return false;
+}
 #endif
 
 /* flag for if timekeeping is suspended */
@@ -719,6 +729,8 @@ static void timekeeping_update_from_shadow(struct tk_data *tkd, unsigned int act
 
 		update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
 		update_fast_timekeeper(&tk->tkr_raw,  &tk_fast_raw);
+	} else if (tk_is_aux(tk)) {
+		vdso_time_update_aux(tk);
 	}
 
 	if (action & TK_CLOCK_WAS_SET)
diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
index df6bada..8ba8b0d 100644
--- a/kernel/time/vsyscall.c
+++ b/kernel/time/vsyscall.c
@@ -136,6 +136,46 @@ void update_vsyscall_tz(void)
 	__arch_sync_vdso_time_data(vdata);
 }
 
+#ifdef CONFIG_POSIX_AUX_CLOCKS
+void vdso_time_update_aux(struct timekeeper *tk)
+{
+	struct vdso_time_data *vdata = vdso_k_time_data;
+	struct vdso_timestamp *vdso_ts;
+	struct vdso_clock *vc;
+	s32 clock_mode;
+	u64 nsec;
+
+	vc = &vdata->aux_clock_data[tk->id - TIMEKEEPER_AUX_FIRST];
+	vdso_ts = &vc->basetime[VDSO_BASE_AUX];
+	clock_mode = tk->tkr_mono.clock->vdso_clock_mode;
+	if (!tk->clock_valid)
+		clock_mode = VDSO_CLOCKMODE_NONE;
+
+	/* copy vsyscall data */
+	vdso_write_begin_clock(vc);
+
+	vc->clock_mode = clock_mode;
+
+	if (clock_mode != VDSO_CLOCKMODE_NONE) {
+		fill_clock_configuration(vc, &tk->tkr_mono);
+
+		vdso_ts->sec	= tk->xtime_sec;
+
+		nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
+		nsec += tk->offs_aux;
+		vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec);
+		nsec = nsec << tk->tkr_mono.shift;
+		vdso_ts->nsec = nsec;
+	}
+
+	__arch_update_vdso_clock(vc);
+
+	vdso_write_end_clock(vc);
+
+	__arch_sync_vdso_time_data(vdata);
+}
+#endif
+
 /**
  * vdso_update_begin - Start of a VDSO update section
  *

The following commit has been merged into the timers/ptp branch of tip:

Commit-ID:     8764009ff21cc773c0c44ecdc987ced5ca853d90
Gitweb:        https://git.kernel.org/tip/8764009ff21cc773c0c44ecdc987ced5ca853d90
Author:        Thomas Weißschuh <thomas.weissschuh@linutronix.de>
AuthorDate:    Tue, 01 Jul 2025 10:58:05 +02:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Mon, 07 Jul 2025 08:58:54 +02:00

vdso/vsyscall: Update auxiliary clock data in the datapage

Expose the auxiliary clock data so it can be read from the vDSO.

Architectures not using the generic vDSO time framework,
namely SPARC64, are not supported.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250701-vdso-auxclock-v1-11-df7d9f87b9b8@linutronix.de

---
 include/linux/timekeeper_internal.h |  6 ++++-
 include/vdso/datapage.h             |  3 ++-
 kernel/time/namespace.c             |  5 ++++-
 kernel/time/timekeeping.c           | 12 ++++++++-
 kernel/time/vsyscall.c              | 40 ++++++++++++++++++++++++++++-
 5 files changed, 66 insertions(+)

diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
index ca79938..c27aac6 100644
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -190,4 +190,10 @@ static inline void update_vsyscall_tz(void)
 }
 #endif
 
+#if defined(CONFIG_GENERIC_GETTIMEOFDAY) && defined(CONFIG_POSIX_AUX_CLOCKS)
+extern void vdso_time_update_aux(struct timekeeper *tk);
+#else
+static inline void vdso_time_update_aux(struct timekeeper *tk) { }
+#endif
+
 #endif /* _LINUX_TIMEKEEPER_INTERNAL_H */
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
index 1864e76..f4c96d9 100644
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h
@@ -38,6 +38,7 @@ struct vdso_arch_data {
 #endif
 
 #define VDSO_BASES	(CLOCK_TAI + 1)
+#define VDSO_BASE_AUX	0
 #define VDSO_HRES	(BIT(CLOCK_REALTIME)		| \
 			 BIT(CLOCK_MONOTONIC)		| \
 			 BIT(CLOCK_BOOTTIME)		| \
@@ -117,6 +118,7 @@ struct vdso_clock {
  * @arch_data:		architecture specific data (optional, defaults
  *			to an empty struct)
  * @clock_data:		clocksource related data (array)
+ * @aux_clock_data:	auxiliary clocksource related data (array)
  * @tz_minuteswest:	minutes west of Greenwich
  * @tz_dsttime:		type of DST correction
  * @hrtimer_res:	hrtimer resolution
@@ -133,6 +135,7 @@ struct vdso_time_data {
 	struct arch_vdso_time_data	arch_data;
 
 	struct vdso_clock		clock_data[CS_BASES];
+	struct vdso_clock		aux_clock_data[MAX_AUX_CLOCKS];
 
 	s32				tz_minuteswest;
 	s32				tz_dsttime;
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index e364227..6674527 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -242,6 +242,11 @@ static void timens_set_vvar_page(struct task_struct *task,
 	for (i = 0; i < CS_BASES; i++)
 		timens_setup_vdso_clock_data(&vc[i], ns);
 
+	if (IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS)) {
+		for (i = 0; i < ARRAY_SIZE(vdata->aux_clock_data); i++)
+			timens_setup_vdso_clock_data(&vdata->aux_clock_data[i], ns);
+	}
+
 out:
 	mutex_unlock(&offset_lock);
 }
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index cbcf090..243fe25 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -66,11 +66,21 @@ static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)
 {
 	return ktime_get_aux_ts64(CLOCK_AUX + tkid - TIMEKEEPER_AUX_FIRST, ts);
 }
+
+static inline bool tk_is_aux(const struct timekeeper *tk)
+{
+	return tk->id >= TIMEKEEPER_AUX_FIRST && tk->id <= TIMEKEEPER_AUX_LAST;
+}
 #else
 static inline bool tk_get_aux_ts64(unsigned int tkid, struct timespec64 *ts)
 {
 	return false;
 }
+
+static inline bool tk_is_aux(const struct timekeeper *tk)
+{
+	return false;
+}
 #endif
 
 /* flag for if timekeeping is suspended */
@@ -719,6 +729,8 @@ static void timekeeping_update_from_shadow(struct tk_data *tkd, unsigned int act
 
 		update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
 		update_fast_timekeeper(&tk->tkr_raw,  &tk_fast_raw);
+	} else if (tk_is_aux(tk)) {
+		vdso_time_update_aux(tk);
 	}
 
 	if (action & TK_CLOCK_WAS_SET)
diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
index df6bada..8ba8b0d 100644
--- a/kernel/time/vsyscall.c
+++ b/kernel/time/vsyscall.c
@@ -136,6 +136,46 @@ void update_vsyscall_tz(void)
 	__arch_sync_vdso_time_data(vdata);
 }
 
+#ifdef CONFIG_POSIX_AUX_CLOCKS
+void vdso_time_update_aux(struct timekeeper *tk)
+{
+	struct vdso_time_data *vdata = vdso_k_time_data;
+	struct vdso_timestamp *vdso_ts;
+	struct vdso_clock *vc;
+	s32 clock_mode;
+	u64 nsec;
+
+	vc = &vdata->aux_clock_data[tk->id - TIMEKEEPER_AUX_FIRST];
+	vdso_ts = &vc->basetime[VDSO_BASE_AUX];
+	clock_mode = tk->tkr_mono.clock->vdso_clock_mode;
+	if (!tk->clock_valid)
+		clock_mode = VDSO_CLOCKMODE_NONE;
+
+	/* copy vsyscall data */
+	vdso_write_begin_clock(vc);
+
+	vc->clock_mode = clock_mode;
+
+	if (clock_mode != VDSO_CLOCKMODE_NONE) {
+		fill_clock_configuration(vc, &tk->tkr_mono);
+
+		vdso_ts->sec	= tk->xtime_sec;
+
+		nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
+		nsec += tk->offs_aux;
+		vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec);
+		nsec = nsec << tk->tkr_mono.shift;
+		vdso_ts->nsec = nsec;
+	}
+
+	__arch_update_vdso_clock(vc);
+
+	vdso_write_end_clock(vc);
+
+	__arch_sync_vdso_time_data(vdata);
+}
+#endif
+
 /**
  * vdso_update_begin - Start of a VDSO update section
  *