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From:   Michael Ellerman <mpe@ellerman.id.au>
To:     Masahiro Yamada <yamada.masahiro@socionext.com>,
        Arnd Bergmann <arnd@arndb.de>
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Subject: Re: [PATCH 00/23] kconfig: move compiler capability tests to Kconfig
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Date:   Thu, 22 Feb 2018 14:22:02 +1100
Message-ID: <87efldr9np.fsf@concordia.ellerman.id.au>
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Masahiro Yamada <yamada.masahiro@socionext.com> writes:
>
<snip>
>
> (Case 3)
> Compiler flag -foo is sensitive to endian-ness.
>
>
> config CC_NEEDS_BIG_ENDIAN
>           def_bool $(cc-option -mbig-endian) && CPU_BIG_ENDIAN
>
> config CC_NEEDS_LITTLE_ENDIAN
>           def_bool $(cc-option -mlittle-endian) && CPU_LITTLE_ENDIAN
>
> config CC_HAS_FOO
>          bool
>          default $(cc-option -mbig-endian -foo) if CC_NEEDS_BIG_ENDIAN
>          default $(cc-option -mlittle-endian -foo) if CC_NEEDS_LITTLE_ENDIAN
>          default $(cc-option -foo)

We may do something like this on powerpc, where we have 32/64-bit and
big/little endian (on 64-bit) and then some ABI options that we
set/unset depending on endian.

The above looks like it could work though.

cheers