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Message-Id: <20250701-vdso-auxclock-v1-11-df7d9f87b9b8@linutronix.de>
Date: Tue, 01 Jul 2025 10:58:05 +0200
From: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
To: Andy Lutomirski <luto@...nel.org>, Thomas Gleixner <tglx@...utronix.de>,
Vincenzo Frascino <vincenzo.frascino@....com>,
Shuah Khan <shuah@...nel.org>,
Anna-Maria Behnsen <anna-maria@...utronix.de>,
Frederic Weisbecker <frederic@...nel.org>, John Stultz <jstultz@...gle.com>,
Stephen Boyd <sboyd@...nel.org>, Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>, Arnd Bergmann <arnd@...db.de>
Cc: linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-arch@...r.kernel.org,
Richard Cochran <richardcochran@...il.com>,
Christopher Hall <christopher.s.hall@...el.com>,
Frederic Weisbecker <frederic@...nel.org>,
Anna-Maria Behnsen <anna-maria@...utronix.de>,
Miroslav Lichvar <mlichvar@...hat.com>,
Werner Abt <werner.abt@...nberg-usa.com>,
David Woodhouse <dwmw2@...radead.org>, Stephen Boyd <sboyd@...nel.org>,
Kurt Kanzenbach <kurt@...utronix.de>, Nam Cao <namcao@...utronix.de>,
Antoine Tenart <atenart@...nel.org>,
Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Subject: [PATCH 11/14] 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@...utronix.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
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