Re: [PATCH 7/7] Kbuild: lto: pass -m32/-m64 to to LDFINAL

Arnd Bergmann
2018-02-02T20:19:07Z

On Fri, Feb 2, 2018 at 7:41 PM, Nicolas Pitre <nicolas.pitre@linaro.org> wrote:
> On Fri, 2 Feb 2018, Arnd Bergmann wrote:
>
>> Building randconfig kernels with a biarch compiler fails with LTO
>> when the final link uses a different target architecture compared
>> to the earlier compilation stages.
>>
>> Setting -m32 or -m64 in ${LDFINAL} solves this problem, though my
>> feeling is that there is a better way to do this. There might also
>> be other from KBUILD_CFLAGS that we may need in LDFINAL.
>
> On ARM I had the same problem as it requires explicit arch flags. I
> therefore used this patch:

> -exec $CC $ARGS
> +case "${KBUILD_VERBOSE}" in
> +*1*)
> + set -x
> + ;;
> +esac
> +
> +exec $CC $KBUILD_CFLAGS $ARGS

Ah, right, that's much simpler. I'll put that in my test tree now and
will see if it works on x86.

Do you have a git tree with other changes for LTO on ARM? I'd
like to try that as well.

Arnd