[PATCH] ARM: fix build error with GCC 4.5.0

[Rabin Vincent]

2010/11/5 Mikael Pettersson <mikpe at it.uu.se>:
> Måns Rullgård writes:
>  > Rabin Vincent <rabin at rab.in> writes:
>  >
>  > > Fix the following error which occurs when building an ARM kernel with
>  > > GCC 4.5.0:
>  > >
>  > >   arm-linux-gcc -Wp,-MD,kernel/.bounds.s.d  -nostdinc
>  > >   [command line edited to remove paths]
>  > >   -D__KERNEL__ -mlittle-endian
>  > >   -Wall -Wundef
>  > >   -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common
>  > >   -Werror-implicit-function-declaration -Wno-format-security
>  > >   -fno-delete-null-pointer-checks -Os -marm -fno-dwarf2-cfi-asm
>  > >   -mabi=aapcs-linux -mno-thumb-interwork -funwind-tables -D__LINUX_ARM_ARCH__=5
>  > >   -march=armv5te -mtune=arm9tdmi -msoft-float -Uarm -fomit-frame-pointer -g
>  > >   -DCC_HAVE_ASM_GOTO    -D"KBUILD_STR(s)=#s"
>  > >   -D"KBUILD_BASENAME=KBUILD_STR(bounds)"  -D"KBUILD_MODNAME=KBUILD_STR(bounds)"
>  > >   -fverbose-asm -S -o kernel/bounds.s kernel/bounds.c
>  > >   kernel/bounds.c:1:0: error: FPA is unsupported in the AAPCS
>  > >
>  > > Signed-off-by: Rabin Vincent <rabin at rab.in>
>  > > ---
>  > > Seen with this compiler:
>  > >
>  > > http://kernel.org/pub/tools/crosstool/files/bin/x86_64/4.5.0/x86_64-gcc-4.5.0-nolibc_arm-linux.tar.bz2
>  > >
>  > >  arch/arm/Makefile |    2 +-
>  > >  1 files changed, 1 insertions(+), 1 deletions(-)
>  > >
>  > > diff --git a/arch/arm/Makefile b/arch/arm/Makefile
>  > > index b87aed0..c06d9ed 100644
>  > > --- a/arch/arm/Makefile
>  > > +++ b/arch/arm/Makefile
>  > > @@ -91,7 +91,7 @@ tune-$(CONFIG_CPU_FEROCEON)      :=$(call cc-option,-mtune=marvell-f,-mtune=xscale)
>  > >  tune-$(CONFIG_CPU_V6)             :=$(call cc-option,-mtune=arm1136j-s,-mtune=strongarm)
>  > >
>  > >  ifeq ($(CONFIG_AEABI),y)
>  > > -CFLAGS_ABI        :=-mabi=aapcs-linux -mno-thumb-interwork
>  > > +CFLAGS_ABI        :=-mabi=aapcs-linux -mno-thumb-interwork -mfpu=vfp
>  >
>  > The real question is why something is trying to use floating-point.
>  > It shouldn't.
>
> Indeed. I suspect an improperly patched or configured gcc-4.5.0,
> or broken kernel sources. Especially considering that the kernel
> passes -msoft-float to gcc (see above).
>
> I know gcc-4.5.0 configured for arm-linux-gnueabi built working EABI
> kernels a few months ago.

The kernel sources are clean Linus' tree, so I guess it must be the
compiler configuration then.  Indeed, running the above mentioned cross
compiler with -msoft-float -mabi=aapcs-linux even on an empty source
file yields the same error.  I've cc'd Tony here who I believe builds
these prebuilt compilers at http://kernel.org/pub/tools/crosstool/.

Rabin