All of lore.kernel.org
 help / color / mirror / Atom feed
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

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
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

  reply	other threads:[~2021-03-15 11:17 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-12  9:55 arm64: kernel/sys.c - silence initialization warnings Valdis Klētnieks
2021-03-12  9:55 ` Valdis Klētnieks
2021-03-15 11:14 ` Catalin Marinas [this message]
2021-03-15 11:14   ` Catalin Marinas
2021-03-15 19:23   ` Christoph Hellwig
2021-03-15 19:23     ` Christoph Hellwig
2021-03-16  0:30     ` Valdis Klētnieks
2021-03-16  0:30       ` Valdis Klētnieks

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210315111433.GA22897@arm.com \
    --to=catalin.marinas@arm.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=valdis.kletnieks@vt.edu \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.