[PATCH v2 1/3] ARM: iwmmxt: Fix Makefile rules for building iwmmxt for Thumb-2

[Nicolas Pitre]

On Thu, 8 Sep 2011, Dave Martin wrote:

> Because gcc/gas have no sane way to turn on individual CPU
> extensions from the command-line, iwmmxt.S was previously built
> with -mcpu=iwmmxt.  Unfortunately, this also downgrades the CPU to
> v5, with the result that this file fails to build for a Thumb-2
> kernel.
> 
> New versions of the tools support -march=<base arch>+iwmmxt, and it
> seems reasonable to require up-to-date tools when building in
> Thumb-2.  So, this patch uses -march=armv7-a+iwmmxt for
> CONFIG_THUMB2_KERNEL=y.
> 
> Signed-off-by: Dave Martin <dave.martin at linaro.org>

I like this one better.

Acked-by: Nicolas Pitre <nicolas.pitre at linaro.org>

As you said, this should be merged with #2/3.



> ---
>  arch/arm/kernel/Makefile |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
> index f7887dc..e03691e 100644
> --- a/arch/arm/kernel/Makefile
> +++ b/arch/arm/kernel/Makefile
> @@ -66,6 +66,18 @@ obj-$(CONFIG_IWMMXT)		+= iwmmxt.o
>  obj-$(CONFIG_CPU_HAS_PMU)	+= pmu.o
>  obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o
>  AFLAGS_iwmmxt.o			:= -Wa,-mcpu=iwmmxt
> +ifdef CONFIG_CPU_V7
> +AFLAGS_iwmmxt.o			:= $(call cc-option,-Wa$(comma)-march=armv7-a+iwmmxt,-DIWMMXT_LEGACY_ASSEMBLER)
> +ifeq ($(AFLAGS_iwmmxt.o),-DIWMMXT_LEGACY_ASSEMBLER)
> +ifdef CONFIG_THUMB2_KERNEL
> +$(error Newer binutils is needed to build iwmmxt support for Thumb-2 kernels.)
> +else
> +$(warning Warning: Building legacy pre-v7 iwmmxt code for a v7 target.\
> +  This is inadvisable.  Please upgrade to newer binutils.)
> +AFLAGS_iwmmxt.o			+= -Wa,-mcpu=iwmmxt
> +endif
> +endif
> +endif # CONFIG_CPU_V7
>  
>  ifneq ($(CONFIG_ARCH_EBSA110),y)
>    obj-y		+= io.o
> -- 
> 1.7.4.1
> 
> 
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