[PATCH 1/2] powerpc/64s: Fix GENERIC_CPU build flags for PPC970 / G5

[Christophe Leroy]

Le 21/09/2022 à 03:41, Nicholas Piggin a écrit :
> Big-endian GENERIC_CPU supports 970, but builds with -mcpu=power5.
> POWER5 is ISA v2.02 whereas 970 is v2.01 plus Altivec. 2.02 added
> the popcntb instruction which a compiler might use.
> 
> Use -mcpu=power4.
> 
> Fixes: 471d7ff8b51b ("powerpc/64s: Remove POWER4 support")
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> ---
>   arch/powerpc/Makefile | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index 02742facf895..140a5e6471fe 100644
> --- a/arch/powerpc/Makefile
> +++ b/arch/powerpc/Makefile
> @@ -152,7 +152,7 @@ CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=power8
>   CFLAGS-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=power9,-mtune=power8)
>   else
>   CFLAGS-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=power7,$(call cc-option,-mtune=power5))
> -CFLAGS-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mcpu=power5,-mcpu=power4)
> +CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=power4
>   endif
>   else ifdef CONFIG_PPC_BOOK3E_64
>   CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=powerpc64

That else ifdef CONFIG_PPC_BOOK3E_64 looks odd.

I might have forgotten to drop something. Since commit d6b551b8f90c 
("powerpc/64e: Fix build failure with GCC 12 (unrecognized opcode: 
`wrteei')") it is not possible anymore to select CONFIG_GENERIC_CPU if 
not book3s64.

Christophe