linux-kernel - Re: [PATCH 2/2] x86: disable CONFIG_GENERIC_HWEIGHT and remove __HAVE_ARCH_SW

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Message-ID: <20190218080949.GA4265@zn.tnic>
Date:   Mon, 18 Feb 2019 09:09:49 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H . Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Kalle Valo <kvalo@...eaurora.org>,
        linux-wireless@...r.kernel.org, Christoph Hellwig <hch@....de>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] x86: disable CONFIG_GENERIC_HWEIGHT and remove
 __HAVE_ARCH_SW_HWEIGHT

On Mon, Feb 18, 2019 at 02:59:31PM +0900, Masahiro Yamada wrote:
> arch/x86/include/asm/arch_hweight.h uses __sw_hweight{32,64} as
> alternatives, but they are implemented in arch/x86/lib/hweight.S
> 
> x86 does not rely on the generic C implementation lib/hweight.c
> at all, so CONFIG_GENERIC_HWEIGHT should be disabled.
> 
> __HAVE_ARCH_SW_HWEIGHT was unneeded in the first place.

Well, it was needed because I didn't think of removing the selection of
GENERIC_HWEIGHT in arch/x86/ at the time:

ld: lib/built-in.o:/dev/shm/bpetkov/kernel/linux/lib/hweight.c:27: multiple definition of `__ksymtab___sw_hweight32'; arch/x86/built-in.o:/dev/shm/bpetkov/kernel/linux/arch/x86/kernel/x8664_ksyms_64.c:47: first defined here
ld: lib/built-in.o:/dev/shm/bpetkov/kernel/linux/lib/hweight.c:67: multiple definition of `__ksymtab___sw_hweight64'; arch/x86/built-in.o:/dev/shm/bpetkov/kernel/linux/arch/x86/kernel/x8664_ksyms_64.c:48: first defined here
ld: arch/x86/lib/built-in.o: in function `__sw_hweight32':
/dev/shm/bpetkov/kernel/linux/arch/x86/lib/hweight.S:12: multiple definition of `__sw_hweight32'; lib/built-in.o:/dev/shm/bpetkov/kernel/linux/lib/hweight.c:15: first defined here
ld: arch/x86/lib/built-in.o: in function `__sw_hweight64':
/dev/shm/bpetkov/kernel/linux/arch/x86/lib/hweight.S:38: multiple definition of `__sw_hweight64'; lib/built-in.o:/dev/shm/bpetkov/kernel/linux/lib/hweight.c:53: first defined here
make: *** [vmlinux] Error 1

-- 
Regards/Gruss,
    Boris.

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