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From: Kumar Gala <galak@kernel.crashing.org>
To: Sebastian Siewior <bigeasy@linutronix.de>
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Subject: Re: [PATCH] powerpc: enforce a non-spe kernel build even on broken
	compilers
Date: Tue, 14 Oct 2008 16:23:05 -0500
References: <20080901142302.GA13754@www.tglx.de>
Cc: linuxppc-dev@ozlabs.org, ths@linutronix.de
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On Sep 1, 2008, at 9:23 AM, Sebastian Siewior wrote:

> From: Thiemo Seufer <ths@linutronix.de>
>
> those two are requried on my fresh gcc 4.3.1
>
> Signed-off-by: Thiemo Seufer <ths@linutronix.de>
> Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de>
> ---
> Not sure if this is intendent or a gcc bug but with -mno-spe
> the spe opcodes were not used floating point anymore but
> for 64bit save/restore for instance.

what code is getting generated for you that is causing issue?

> arch/powerpc/Makefile |    3 +++
> 1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index b7d4c4c..3727e4f 100644
> --- a/arch/powerpc/Makefile
> +++ b/arch/powerpc/Makefile
> @@ -108,7 +108,10 @@ endif
> KBUILD_CFLAGS += $(call cc-option,-mno-altivec)
>
> # No SPE instruction when building kernel
> +# (We use all available options to help semi-broken compilers)
> KBUILD_CFLAGS += $(call cc-option,-mno-spe)
> +KBUILD_CFLAGS += $(call cc-option,-mspe=no)

Why does -mno-spe work?

 From my gcc-4.3 info pages:

`-mspe=YES/NO'
      This option has been deprecated.  Use `-mspe' and `-mno-spe'
      instead.

> +KBUILD_CFLAGS += $(call cc-option,-mabi=no-spe)

is the -mabi=no-spe really needed?

- k