[5/5] include tuning options into Makefile

[Arnd Bergmann]

On Monday 21 July 2008, Marvin wrote:

> +# optimize for specific cpu
> +ifeq ($(CONFIG_TUNE_RS64),y)
> +    KBUILD_CFLAGS += $(call cc-option,-mcpu=rs64)
> +else ifeq ($(CONFIG_TUNE_POWER3),y)
> +    KBUILD_CFLAGS += $(call cc-option,-mcpu=power3)
> +else ifeq ($(CONFIG_TUNE_POWER4),y)
> +    KBUILD_CFLAGS += $(call cc-option,-mcpu=$(P4CPU))
> +else ifeq ($(CONFIG_TUNE_CELL),y)
> +    KBUILD_CFLAGS += $(call cc-option,-mcpu=cell,-mtune=cell)
> +else ifeq ($(CONFIG_TUNE_POWER5),y)
> +    KBUILD_CFLAGS += $(call cc-option,-mcpu=power5,-mtune=power5)
> +else ifeq ($(CONFIG_TUNE_POWER6),y)
> +    KBUILD_CFLAGS += $(call cc-option,-mcpu=power6,-mtune=power6)
>  endif
> -else
> -LDFLAGS_MODULE += arch/powerpc/lib/crtsavres.o

I think it would be easier to express this logic in Kconfig than in
Makefile.

> +
> +ifneq ($(CONFIG_OPT_EXCLUSIVE),y)
> +    KBUILD_CFLAGS := $(subst mcpu,mtune,$(KBUILD_CFLAGS))
>  endif
>  

This still doesn't allow the most interesting case where you want to
optimize for a modern CPU but still allow older ones, e.g.
"-mcpu=power4 -mtune=power6".

	Arnd <><