linux-kernel - [PATCH 02/14] vdso/vsyscall: Introduce a helper to fill clock configurations

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Message-Id: <20250701-vdso-auxclock-v1-2-df7d9f87b9b8@linutronix.de>
Date: Tue, 01 Jul 2025 10:57:56 +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 02/14] vdso/vsyscall: Introduce a helper to fill clock
 configurations

The logic to configure a 'struct vdso_clock' from a
'struct tk_read_base' is copied two times.
Split it into a shared function to reduce the duplication,
especially as another user will be added for auxiliary clocks.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
---
 kernel/time/vsyscall.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
index 32ef27c71b57aaa4ed898c0dbfdefcb73b8ff56a..d655df2597336f7305bfc74e2a87c651f314267b 100644
--- a/kernel/time/vsyscall.c
+++ b/kernel/time/vsyscall.c
@@ -15,26 +15,25 @@
 
 #include "timekeeping_internal.h"
 
+static inline void fill_clock_configuration(struct vdso_clock *vc, const struct tk_read_base *base)
+{
+	vc->cycle_last	= base->cycle_last;
+#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT
+	vc->max_cycles	= base->clock->max_cycles;
+#endif
+	vc->mask	= base->mask;
+	vc->mult	= base->mult;
+	vc->shift	= base->shift;
+}
+
 static inline void update_vdso_time_data(struct vdso_time_data *vdata, struct timekeeper *tk)
 {
 	struct vdso_clock *vc = vdata->clock_data;
 	struct vdso_timestamp *vdso_ts;
 	u64 nsec, sec;
 
-	vc[CS_HRES_COARSE].cycle_last	= tk->tkr_mono.cycle_last;
-#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT
-	vc[CS_HRES_COARSE].max_cycles	= tk->tkr_mono.clock->max_cycles;
-#endif
-	vc[CS_HRES_COARSE].mask		= tk->tkr_mono.mask;
-	vc[CS_HRES_COARSE].mult		= tk->tkr_mono.mult;
-	vc[CS_HRES_COARSE].shift	= tk->tkr_mono.shift;
-	vc[CS_RAW].cycle_last		= tk->tkr_raw.cycle_last;
-#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT
-	vc[CS_RAW].max_cycles		= tk->tkr_raw.clock->max_cycles;
-#endif
-	vc[CS_RAW].mask			= tk->tkr_raw.mask;
-	vc[CS_RAW].mult			= tk->tkr_raw.mult;
-	vc[CS_RAW].shift		= tk->tkr_raw.shift;
+	fill_clock_configuration(&vc[CS_HRES_COARSE],	&tk->tkr_mono);
+	fill_clock_configuration(&vc[CS_RAW],		&tk->tkr_raw);
 
 	/* CLOCK_MONOTONIC */
 	vdso_ts		= &vc[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC];

-- 
2.50.0