Re: [PATCH 3/7] MIPS: csrc-r4k: Replace CONFIG_GENERIC_GETTIMEOFDAY ifdeffery with IS_ENABLED()

From: Thomas Gleixner <tglx@kernel.org>
To: "Thomas Weißschuh" <thomas.weissschuh@linutronix.de>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Vincenzo Frascino" <vincenzo.frascino@arm.com>,
	"Nathan Chancellor" <nathan@kernel.org>,
	"Nicolas Schier" <nsc@kernel.org>,
	"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>,
	"Daniel Lezcano" <daniel.lezcano@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Marc Zyngier" <maz@kernel.org>, "Paul Walmsley" <pjw@kernel.org>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Albert Ou" <aou@eecs.berkeley.edu>,
	"Alexandre Ghiti" <alex@ghiti.fr>,
	"Huacai Chen" <chenhuacai@kernel.org>,
	"WANG Xuerui" <kernel@xen0n.name>
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-kbuild@vger.kernel.org, linux-mips@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-riscv@lists.infradead.org, loongarch@lists.linux.dev,
	"Thomas Weißschuh" <thomas.weissschuh@linutronix.de>
Subject: Re: [PATCH 3/7] MIPS: csrc-r4k: Replace CONFIG_GENERIC_GETTIMEOFDAY ifdeffery with IS_ENABLED()
Date: Wed, 15 Jul 2026 10:25:19 +0200	[thread overview]
Message-ID: <87wluwoe1c.ffs@fw13> (raw)
In-Reply-To: <20260709-vdso-arch-clockmodes-v1-3-3fd780bbf851@linutronix.de>

On Thu, Jul 09 2026 at 13:32, Thomas Weißschuh wrote:
> Now that there is a dummy declaration of VDSO_CLOCKMODE_R4K, even if no
> vDSO is built, the ugly ifdeffery can be replaced with a cleaner
> IS_ENABLED() check.

Duh. This stuff is really obfuscated. I just realized that the previous
one actually expands the architecture defines to non-defined integer
variable declarations.

Smart, but seriously?

I just double checked and it turns out that none of this ifdeffery is
required. If CONFIG_GENERIC_GETTIMEOFDAY is disabled, then it does not
matter at all whether the actual ARCH_CLOCK_VDSO_MODE is set in
clocksource::vdso_mode or not.

Nothing uses the vdso mode field outside of update_vsyscall and that's
compiled out when CONFIG_GENERIC_GETTIMEOFDAY=n.

So all what's required is:

--- a/include/vdso/clocksource.h
+++ b/include/vdso/clocksource.h
@@ -3,14 +3,11 @@
 #define __VDSO_CLOCKSOURCE_H
 
 #include <vdso/limits.h>
-
-#ifdef CONFIG_GENERIC_GETTIMEOFDAY
 #include <asm/vdso/clocksource.h>
-#endif /* CONFIG_GENERIC_GETTIMEOFDAY */
 
 enum vdso_clock_mode {
 	VDSO_CLOCKMODE_NONE,
-#ifdef CONFIG_GENERIC_GETTIMEOFDAY
+#ifdef VDSO_ARCH_CLOCKMODES
 	VDSO_ARCH_CLOCKMODES,
 #endif
 	VDSO_CLOCKMODE_MAX,

and then you can just unconditionally set clocksource::vdso_clock_mode
in all drivers.

No?

Thanks,

        tglx

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