Re: [PATCH] Disable -fconserve-stack on ARM

From: Catalin Marinas
Date: Tue May 31 2011 - 12:30:46 EST


On Sat, May 28, 2011 at 04:34:17PM +0100, Andi Kleen wrote:
> Disable -fconserve-stack on ARM
>
> There are reports that -fconserve-stack misaligns variables on the stack.
> Disable it for ARM to work around this gcc bug.
>
> Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
>
> diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> index 25750bc..0883cff 100644
> --- a/arch/arm/Makefile
> +++ b/arch/arm/Makefile
> @@ -41,6 +41,10 @@ ifeq ($(CONFIG_CC_STACKPROTECTOR),y)
> KBUILD_CFLAGS +=-fstack-protector
> endif
>
> +# ARM gcc developers unfortunately broke -fconserve-stack. It misaligns
> +# variables on the stack
> +KBUILD_CFLAGS += $(call cc-option,-fno-conserve-stack)

Didn't work, on the gcc command line we get -fno-conserve-stack followed
by -fconserve-stack from the top makefile and it seems that the latter
takes priority.

--
Catalin

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