Re: [PATCH 00/23] kconfig: move compiler capability tests to Kconfig

Michael Ellerman <[email protected]> Thu, 22 Feb 2018 14:22:02 +1100

Newsgroups	gmane.linux.ports.ppc.embedded,gmane.linux.kernel.hardened.devel,gmane.linux.ports.sparc,gmane.linux.ports.sh.devel,gmane.linux.uml.devel,gmane.linux.kbuild.devel,gmane.linux.uml.user,gmane.linux.documentation,gmane.linux.kernel
Message-ID	<[email protected]>

Masahiro Yamada <[email protected]> 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