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From: Nathan Chancellor <nathan@kernel.org>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
	Nick Desaulniers <ndesaulniers@google.com>,
	Nicolas Schier <nicolas@fjasle.eu>
Subject: Re: [PATCH] kbuild: get lib-y objects back to static library
Date: Wed, 23 Aug 2023 13:20:40 -0700	[thread overview]
Message-ID: <20230823202040.GA2236267@dev-arch.thelio-3990X> (raw)
In-Reply-To: <20230823120816.824352-1-masahiroy@kernel.org>

Hi Masahiro,

On Wed, Aug 23, 2023 at 09:08:16PM +0900, Masahiro Yamada wrote:
> Revert the following two commits:
> 
>  - 7273ad2b08f8 ("kbuild: link lib-y objects to vmlinux forcibly when CONFIG_MODULES=y")
>  - 7f2084fa55e6 ("[kbuild] handle exports in lib-y objects reliably")
> 
> Now, lib-y is back to static library again, and the link order is
> consistent w/wo CONFIG_MODULES.
> 
> Since commit ddb5cdbafaaa ("kbuild: generate KSYMTAB entries by
> modpost"), .vmlinux.export.c contains references to exported symbols.
> If a symbol in a lib-y object is exported, that object is always linked
> even without any explicit user in vmlinux.
> 
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---
> 
>  Makefile | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index 87a9eef3fb4b..71e9c65d9eae 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1113,12 +1113,7 @@ export ARCH_DRIVERS	:= $(drivers-y) $(drivers-m)
>  # Externally visible symbols (used by link-vmlinux.sh)
>  
>  KBUILD_VMLINUX_OBJS := ./built-in.a
> -ifdef CONFIG_MODULES
> -KBUILD_VMLINUX_OBJS += $(patsubst %/, %/lib.a, $(filter %/, $(libs-y)))
> -KBUILD_VMLINUX_LIBS := $(filter-out %/, $(libs-y))
> -else
>  KBUILD_VMLINUX_LIBS := $(patsubst %/,%/lib.a, $(libs-y))
> -endif
>  
>  export KBUILD_VMLINUX_LIBS
>  export KBUILD_LDS          := arch/$(SRCARCH)/kernel/vmlinux.lds
> -- 
> 2.39.2
> 

The build error that prompted 7273ad2b08f8 from [1] appears to return
with this patch, for example:

$ make -skj"$(nproc)" ARCH=arm64 LLVM=1 O=build mrproper virtconfig all
...
ERROR: modpost: "__memcat_p" [drivers/hwtracing/stm/stm_core.ko] undefined!
...

[1]: https://github.com/ClangBuiltLinux/linux/issues/515

Cheers,
Nathan

  reply	other threads:[~2023-08-23 20:21 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-23 12:08 [PATCH] kbuild: get lib-y objects back to static library Masahiro Yamada
2023-08-23 20:20 ` Nathan Chancellor [this message]
2023-08-24 18:59   ` Nathan Chancellor
2023-08-25 16:58     ` Nick Desaulniers
2023-08-26  0:06       ` Masahiro Yamada
2023-08-26  0:55         ` Nick Desaulniers
2023-08-24  1:44 ` Masahiro Yamada
2023-08-26  2:37 ` kernel test robot

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