From: Ian Abbott <abbotti@mev.co.uk>
To: barebox@lists.infradead.org
Subject: Re: Build failures with CC=arm-linux-gnueabihf-gcc-11
Date: Fri, 19 Nov 2021 10:30:02 +0000 [thread overview]
Message-ID: <3bc9c94a-55b2-c7b3-0546-7959bb45219c@mev.co.uk> (raw)
In-Reply-To: <20211119092916.GD5253@pengutronix.de>
Hi Michael,
On 19/11/2021 09:29, Michael Olbrich wrote:
> On Thu, Nov 18, 2021 at 03:32:04PM +0000, Ian Abbott wrote:
>> Hi,
>>
>> My Debian "testing" build system updated the default version of
>> arm-linux-gnueabihf-gcc from 10.x to 11.x. Building barebox in thumb-2 mode
>> for an ARMv7 (it's a SoCFPGA) with this compiler fails with assembler errors
>> such as:
>>
>> CC common/state/state_variables.o
>> {standard input}: Assembler messages:
>> {standard input}:1535: Error: selected processor does not support `rev
>> r3,r3' in Thumb mode
>> {standard input}:1576: Error: selected processor does not support `rev
>> r3,r3' in Thumb mode
>>
>> Building in verbose mode (V=1) shows that "make" has selected the compile
>> flags `-march=armv5t -Wa,-march=armv7-a` instead of the usual
>> `-march=armv7-a`.
>>
>> Looking a little deeper, all of the following lines in "arch/arm/Makefile"
>> are failing to select the first option and defaulting to the second option
>> (if any):
>
> It probably is added from here:
>
> arch-$(CONFIG_CPU_32v7) :=-D__LINUX_ARM_ARCH__=7 $(call cc-option,-march=armv7-a,-march=armv5t -Wa$(comma)-march=armv7-a)
>
> The check for -march=armv7-a fails for some reason so the fallback is used.
Yes, I showed the exact failure resulting from the cc-option call
further down my email:
cc1: error: ‘-mfloat-abi=hard’: selected architecture lacks an FPU
> I've seen this when CC is a wrapper and already adds -mcpu=... to the
> commandline. In that case gcc now complains about the combination and the
> check fails.
In my case, CC was set by this "build.sh" script:
#! /bin/sh
SRC="../barebox-de0-nano-soc"
ARCH="arm"
CROSS_COMPILE=arm-linux-gnueabihf-
CC='$(CROSS_COMPILE)gcc-11'
make -C "$SRC" O=`pwd` ARCH="$ARCH" CROSS_COMPILE="$CROSS_COMPILE"
CC="$CC" $*
so after expansion, CC=arm-linux-gnueabihf-gcc-11
>
> Michael
Cheers, Ian.
>
>> arch-$(CONFIG_CPU_64v8) := -D__LINUX_ARM_ARCH__=8 $(call
>> cc-option,-march=armv8-a)
>> arch-$(CONFIG_CPU_32v7) :=-D__LINUX_ARM_ARCH__=7 $(call
>> cc-option,-march=armv7-a,-march=armv5t -Wa$(comma)-march=armv7-a)
>> arch-$(CONFIG_CPU_32v6) :=-D__LINUX_ARM_ARCH__=6 $(call
>> cc-option,-march=armv6,-march=armv5t -Wa$(comma)-march=armv6)
>> arch-$(CONFIG_CPU_32v5) :=-D__LINUX_ARM_ARCH__=5 $(call
>> cc-option,-march=armv5te,-march=armv4t)
>>
>> The error from the compiler is:
>>
>> cc1: error: ‘-mfloat-abi=hard’: selected architecture lacks an FPU
>>
>> (Note: the error is only shown after tweaking the `try-run` command in
>> "scripts/Kbuild.include" so that it does not send error output to
>> "/dev/null".)
>>
>> That error seems to be a change in behaviour between GCC 10.x and GCC 11.x.
>>
>> At the point in the Makefile that the error occurs, the `-msoft-float`
>> option has not been added to `KBUILD_CPPFLAGS` yet. That is done further
>> down the Makefile except for `CONFIG_CPU_V8`. I guess it needs to be added
>> somewhere before problematic lines in the Makefile. I'm not sure if
>> `-msoft-float` is also needed for 64-bit ARMv8, but the error suggests it is
>> required there too.
>
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prev parent reply other threads:[~2021-11-19 10:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-18 15:32 Ian Abbott
2021-11-19 9:29 ` Michael Olbrich
2021-11-19 10:30 ` Ian Abbott [this message]
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