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From: Dave Martin <dave.martin@linaro.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 05/11] ARM: vfp: use -mfloat-abi=soft to build vfp
Date: Mon, 3 Oct 2011 15:04:12 +0100	[thread overview]
Message-ID: <20111003140411.GB2117@arm.com> (raw)
In-Reply-To: <1317496920-7764-6-git-send-email-arnd@arndb.de>

On Sat, Oct 01, 2011 at 09:21:54PM +0200, Arnd Bergmann wrote:
> Distros are starting to ship with toolchains defaulting to
> hardfloat. Using such a compiler to build the kernel fails
> in the VFP directory with
> 
> arch/arm/vfp/entry.S:1:0: sorry, unimplemented: -mfloat-abi=hard and VFP
> 
> Adding -mfloat-abi=soft to the gcc command line fixes this.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  arch/arm/vfp/Makefile |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/vfp/Makefile b/arch/arm/vfp/Makefile
> index 6de73aa..a81404c 100644
> --- a/arch/arm/vfp/Makefile
> +++ b/arch/arm/vfp/Makefile
> @@ -7,7 +7,7 @@
>  # ccflags-y := -DDEBUG
>  # asflags-y := -DDEBUG
>  
> -KBUILD_AFLAGS	:=$(KBUILD_AFLAGS:-msoft-float=-Wa,-mfpu=softvfp+vfp)
> +KBUILD_AFLAGS	:=$(KBUILD_AFLAGS:-msoft-float=-Wa,-mfpu=softvfp+vfp -mfloat-abi=soft)

Although -mfpu=softvfp+vfp and -mfloat-abi=soft look mutually
contradictory, this seems to have the correct effect, i.e. the
assembler allows floating-point instructions but marks the resulting
object as using the soft-float calling conventions.

The binutils documentation also seems to confirm that that's what
should happen.

I don't see another combination of options for getting this effect.


So, if you like:

Reviewed-by: Dave Martin <dave.martin@linaro.org>

Cheers
---Dave

  reply	other threads:[~2011-10-03 14:04 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-01 19:21 [PATCH 00/11] Generic ARM fixes for randconfig Arnd Bergmann
2011-10-01 19:21 ` [PATCH 01/11] ARM: export rtc_lock for nvram driver Arnd Bergmann
2011-10-02 15:21   ` Russell King - ARM Linux
2011-10-01 19:21 ` [PATCH 02/11] ARM: SMP depends on MMU Arnd Bergmann
2011-10-01 19:21 ` [PATCH 03/11] ARM: always use ARM_UNWIND for thumb2 kernels Arnd Bergmann
2011-10-01 19:21 ` [PATCH 04/11] ARM: allow building alignment.c without PROC_FS Arnd Bergmann
2011-10-01 19:21 ` [PATCH 05/11] ARM: vfp: use -mfloat-abi=soft to build vfp Arnd Bergmann
2011-10-03 14:04   ` Dave Martin [this message]
2011-10-01 19:21 ` [PATCH 06/11] ARM: pm: let platforms select cpu_suspend support Arnd Bergmann
2011-10-01 19:21 ` [PATCH 07/11] ARM: limit CONFIG_HAVE_IDE to platforms that do Arnd Bergmann
2011-10-01 19:21 ` [PATCH 08/11] ARM: add io{read,write}{16,32}be functions Arnd Bergmann
2011-10-01 19:21 ` [PATCH 09/11] ARM: pci: always export pcibios_bus_to_resource Arnd Bergmann
2011-10-01 19:21 ` [PATCH 10/11] ARM: OC_ETM should not select ARM_AMBA Arnd Bergmann
2011-10-01 19:22 ` [PATCH 11/11] ARM: common/vic: use proper __iomem annotations Arnd Bergmann
2011-10-05  1:24   ` H Hartley Sweeten
2011-10-02 13:46 ` [PATCH 12/11] ARM: include linux/highmem.h in uaccess functions Arnd Bergmann
2011-10-02 15:36 ` [PATCH 00/11] Generic ARM fixes for randconfig Russell King - ARM Linux
2011-10-02 15:42   ` Arnd Bergmann
2011-10-02 15:47     ` Russell King - ARM Linux

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