linux-kernel - [PATCH 07/14] vdso/gettimeofday: Introduce vdso_clockid

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Message-Id: <20250701-vdso-auxclock-v1-7-df7d9f87b9b8@linutronix.de>
Date: Tue, 01 Jul 2025 10:58:01 +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 07/14] vdso/gettimeofday: Introduce vdso_clockid_valid()

With the upcoming addition of auxiliary clocks the clockid validation will
become more complicated. Split it into a dedicated function to keep the
code readable.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
---
 lib/vdso/gettimeofday.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index c5266532a097c06f33d12e345c695357d75abf42..215151bd5a1320ee6edda8f334d47c739577f696 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -71,6 +71,12 @@ static inline bool vdso_cycles_ok(u64 cycles)
 }
 #endif
 
+static __always_inline bool vdso_clockid_valid(clockid_t clock)
+{
+	/* Check for negative values or invalid clocks */
+	return likely((u32) clock < MAX_CLOCKS);
+}
+
 #ifdef CONFIG_TIME_NS
 
 #ifdef CONFIG_GENERIC_VDSO_DATA_STORE
@@ -268,8 +274,7 @@ __cvdso_clock_gettime_common(const struct vdso_time_data *vd, clockid_t clock,
 	const struct vdso_clock *vc = vd->clock_data;
 	u32 msk;
 
-	/* Check for negative values or invalid clocks */
-	if (unlikely((u32) clock >= MAX_CLOCKS))
+	if (!vdso_clockid_valid(clock))
 		return false;
 
 	/*
@@ -405,8 +410,7 @@ bool __cvdso_clock_getres_common(const struct vdso_time_data *vd, clockid_t cloc
 	u32 msk;
 	u64 ns;
 
-	/* Check for negative values or invalid clocks */
-	if (unlikely((u32) clock >= MAX_CLOCKS))
+	if (!vdso_clockid_valid(clock))
 		return false;
 
 	if (IS_ENABLED(CONFIG_TIME_NS) &&

-- 
2.50.0