[PATCH v2 1/5] powerpc/Makefiles: Fix clang/llvm build

[Nick Desaulniers]

On Thu, Sep 13, 2018 at 9:07 PM Joel Stanley <joel at jms.id.au> wrote:
>
> From: Anton Blanchard <anton at samba.org>
>
> Commit 15a3204d24a3 ("powerpc/64s: Set assembler machine type to POWER4")
> passes -mpower4 to the assembler. We have more recent instructions in our
> assembly files, but gas permits them. The clang/llvm integrated assembler
> is more strict, and we get a build failure.

Note that we disable clang's integrated assembler in the top level
Makefile for now, but it will still validate constraints for inline
assembly.  Do you know which case is meant by "build failure?"

Is there a link to the Clang bug?  It would be good to have that
context in the commit message.

>
> Fix this by calling the assembler with -mcpu=power8 if as supports it,
> else fall back to power4.
>
> Suggested-by: Nicholas Piggin <npiggin at gmail.com>
> Signed-off-by: Anton Blanchard <anton at samba.org>
> Signed-off-by: Joel Stanley <joel at jms.id.au>
> ---
>  arch/powerpc/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index 11a1acba164a..a70639482053 100644
> --- a/arch/powerpc/Makefile
> +++ b/arch/powerpc/Makefile
> @@ -238,7 +238,7 @@ cpu-as-$(CONFIG_4xx)                += -Wa,-m405
>  cpu-as-$(CONFIG_ALTIVEC)       += $(call as-option,-Wa$(comma)-maltivec)
>  cpu-as-$(CONFIG_E200)          += -Wa,-me200
>  cpu-as-$(CONFIG_E500)          += -Wa,-me500
> -cpu-as-$(CONFIG_PPC_BOOK3S_64) += -Wa,-mpower4
> +cpu-as-$(CONFIG_PPC_BOOK3S_64) += $(call as-option,-Wa$(comma)-mpower8,-Wa$(comma)-mpower4)
>  cpu-as-$(CONFIG_PPC_E500MC)    += $(call as-option,-Wa$(comma)-me500mc)
>
>  KBUILD_AFLAGS += $(cpu-as-y)
> --
> 2.17.1
>

-- 
Thanks,
~Nick Desaulniers