From: Catalin Marinas <catalin.marinas@arm.com>
To: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
Cc: Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: arm64: kernel/sys.c - silence initialization warnings.
Date: Mon, 15 Mar 2021 11:14:34 +0000 [thread overview]
Message-ID: <20210315111433.GA22897@arm.com> (raw)
In-Reply-To: <162859.1615542946@turing-police>
On Fri, Mar 12, 2021 at 04:55:46AM -0500, Valdis Klētnieks wrote:
> Building arch/arm64/kernel/sys.o with W=1 throws over 300 warnings:
>
> /usr/src/linux-next/arch/arm64/kernel/sys.c:56:40: warning: initialized field overwritten [-Woverride-init]
> 56 | #define __SYSCALL(nr, sym) [nr] = __arm64_##sym,
> | ^~~~~~~~
> /usr/src/linux-next/include/uapi/asm-generic/unistd.h:29:37: note: in expansion of macro '__SYSCALL'
> 29 | #define __SC_COMP(_nr, _sys, _comp) __SYSCALL(_nr, _sys)
> | ^~~~~~~~~
> /usr/src/linux-next/include/uapi/asm-generic/unistd.h:34:1: note: in expansion of macro '__SC_COMP'
> 34 | __SC_COMP(__NR_io_setup, sys_io_setup, compat_sys_io_setup)
> | ^~~~~~~~~
>
> We know that's pretty much the file's purpose in life, so tell the
> build system to not remind us. This makes the 1 other warning a
> lot more noticeable.
>
> Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
>
> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> index ed65576ce710..916b21d2b35b 100644
> --- a/arch/arm64/kernel/Makefile
> +++ b/arch/arm64/kernel/Makefile
> @@ -8,6 +8,7 @@ CFLAGS_armv8_deprecated.o := -I$(src)
> CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)
> CFLAGS_REMOVE_insn.o = $(CC_FLAGS_FTRACE)
> CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE)
> +CFLAGS_sys.o += $(call cc-disable-warning, override-init)
We do similar initialisation in arch/arm64/kernel/sys32.c and
arch/arm64/kernel/traps.c for example. It's a pretty common pattern
throughout the kernel.
So we either treat W=1 output as diff against the vanilla kernel when
checking new patches or we remove override-init altogether from W=1.
Mark Rutland pointed me to an older thread:
https://lore.kernel.org/linux-arm-kernel/20190809083251.GA48423@lakrids.cambridge.arm.com/
--
Catalin
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next prev parent reply other threads:[~2021-03-15 11:17 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-12 9:55 arm64: kernel/sys.c - silence initialization warnings Valdis Klētnieks
2021-03-15 11:14 ` Catalin Marinas [this message]
2021-03-15 19:23 ` Christoph Hellwig
2021-03-16 0:30 ` Valdis Klētnieks
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