[Buildroot] EABIhf: breaks kernel build

[Buildroot] EABIhf: breaks kernel build

[Yann E. MORIN]

Thomas, All,

Since the ARM EABIhf stuff was committed, the Linux kernel build is
broken, and fails with this message:
    armv6-rpi36-linux-gnueabi-gcc: error: -mfloat-abi=soft and
    -mfloat-abi=hard may not be used together

This is because -mfloat-abi=hard is hard-coded in the wrapper, but the
kernel wants to pass -msoft-float.

See attach exerpt of my build log (with a instrumented ext-ttolchain
wrapper). Notice argv[6] and argv[41]:

    argv[6]='-mfloat-abi=hard'
    argv[41]='-msoft-float'

argv[6] is out hard-coded float ABI option, while argv[41] is passed by
the kernel.

I don't know how to solve this.

The trivial and immediate idea would be to have a black-list of
arguments and exclude the ones we pass that conflict with the ones
passed on the command line, but this will be *very* complex and always
incomplete.

An alternate idea would be to detect we're building a Linux kernel by
looking at -D__KERNEL__ in the command line arguments, and if so, not
pass our hard-coded args. This would work for the Linux kernel, but
would break for other packages (eg. U-Boot?).

Another way would be to look at the environment and check if a variable
is set (eg. BR_IN_KERNEL_OR_UBOOT_OR_WHATEVER) and in this case not pass
our hard-coded options. While it would work from inside Buildroot, it
would break as soon as the user would want to use the toolchain directly
from outside Buildroot.

Or simply not pass -mfloat-abi=hard at all.

Apart these, I don't see how we can fix this.

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'
-------------- next part --------------
>>> linux 245f716 Building
PATH="/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/host/bin:/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/host/usr/bin:/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/host/usr/sbin/:/home/ymorin/bin:/home/ymorin/bin:/opt/w_scan/bin:/opt/mutt-sidebar/bin:/opt/dvb-apps/bin:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games" PERLLIB="/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/host/usr/lib/perl" /usr/bin/make -j1 HOSTCC="/usr/bin/gcc" HOSTCFLAGS="" ARCH=arm INSTALL_MOD_PATH=/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/target CROSS_COMPILE=" /home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/host/usr/bin/armv6-rpi36-linux-gnueabi-" DEPMOD=/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/host/usr/sbin/depmod V=1 -C /home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/build/linux-245f716 zImage
path='/home/ymorin/x-tools/armv6-rpi36-linux-gnueabi/bin/armv6-rpi36-linux-gnueabi-gcc'
argv[0]='/home/ymorin/x-tools/armv6-rpi36-linux-gnueabi/bin/armv6-rpi36-linux-gnueabi-gcc'
argv[1]='--sysroot'
argv[2]='/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/host/usr/arm-buildroot-linux-gnueabi/sysroot'
argv[3]='-march=armv6zk'
argv[4]='-mtune=arm1176jzf-s'
argv[5]='-mabi=aapcs-linux'
argv[6]='-mfloat-abi=hard'
argv[7]='-marm'
argv[8]='-pipe'
argv[9]='-print-file-name=include'
rm -f include/config/kernel.release
echo "3.6.11$(/bin/sh /home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/build/linux-245f716/scripts/setlocalversion /home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/build/linux-245f716)" > include/config/kernel.release
/usr/bin/make -f /home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/build/linux-245f716/scripts/Makefile.asm-generic \
	            obj=arch/arm/include/generated/asm
set -e; : '  CHK     include/linux/version.h'; mkdir -p include/linux/; 	(echo \#define LINUX_VERSION_CODE 198155; echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))';) < /home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/build/linux-245f716/Makefile > include/linux/version.h.tmp; if [ -r include/linux/version.h ] && cmp -s include/linux/version.h include/linux/version.h.tmp; then rm -f include/linux/version.h.tmp; else : '  UPD     include/linux/version.h'; mv -f include/linux/version.h.tmp include/linux/version.h; fi
set -e; : '  CHK     include/generated/utsrelease.h'; mkdir -p include/generated/; 	if [ `echo -n "3.6.11-yem" | wc -c ` -gt 64 ]; then echo '"3.6.11-yem" exceeds 64 characters' >&2; exit 1; fi; (echo \#define UTS_RELEASE \"3.6.11-yem\";) < include/config/kernel.release > include/generated/utsrelease.h.tmp; if [ -r include/generated/utsrelease.h ] && cmp -s include/generated/utsrelease.h include/generated/utsrelease.h.tmp; then rm -f include/generated/utsrelease.h.tmp; else : '  UPD     include/generated/utsrelease.h'; mv -f include/generated/utsrelease.h.tmp include/generated/utsrelease.h; fi
mkdir -p .tmp_versions 
/usr/bin/make -f scripts/Makefile.build obj=scripts/basic
rm -f .tmp_quiet_recordmcount
/usr/bin/make -f scripts/Makefile.build obj=arch/arm/tools include/generated/mach-types.h
make[3]: `include/generated/mach-types.h' is up to date.
/usr/bin/make -f scripts/Makefile.build obj=.
mkdir -p kernel/
  /home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/host/usr/bin/armv6-rpi36-linux-gnueabi-gcc -Wp,-MD,kernel/.bounds.s.d  -nostdinc -isystem /home/ymorin/x-tools/armv6-rpi36-linux-gnueabi/lib/gcc/armv6-rpi36-linux-gnueabi/4.8.1/include -I/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/build/linux-245f716/arch/arm/include -Iarch/arm/include/generated -Iinclude  -include /home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/build/linux-245f716/include/linux/kconfig.h -D__KERNEL__ -mlittle-endian -Iarch/arm/mach-bcm2708/include -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -Werror-implicit-function-declaration -Wno-format-security -fno-delete-null-pointer-checks -O2 -marm -fno-dwarf2-cfi-asm -fno-omit-frame-pointer -mapcs -mno-sched-prolog -mabi=aapcs-linux -mno-thumb-interwork -D__LINUX_ARM_ARCH__=6 -march=armv6 -mtune=arm1136j-s -msoft-float -Uarm -fno-omit-frame-pointer -fno-optimize-sibling-calls -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
path='/home/ymorin/x-tools/armv6-rpi36-linux-gnueabi/bin/armv6-rpi36-linux-gnueabi-gcc'
argv[0]='/home/ymorin/x-tools/armv6-rpi36-linux-gnueabi/bin/armv6-rpi36-linux-gnueabi-gcc'
argv[1]='--sysroot'
argv[2]='/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/host/usr/arm-buildroot-linux-gnueabi/sysroot'
argv[3]='-march=armv6zk'
argv[4]='-mtune=arm1176jzf-s'
argv[5]='-mabi=aapcs-linux'
argv[6]='-mfloat-abi=hard'
argv[7]='-marm'
argv[8]='-pipe'
argv[9]='-Wp,-MD,kernel/.bounds.s.d'
argv[10]='-nostdinc'
argv[11]='-isystem'
argv[12]='/home/ymorin/x-tools/armv6-rpi36-linux-gnueabi/lib/gcc/armv6-rpi36-linux-gnueabi/4.8.1/include'
argv[13]='-I/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/build/linux-245f716/arch/arm/include'
argv[14]='-Iarch/arm/include/generated'
argv[15]='-Iinclude'
argv[16]='-include'
argv[17]='/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/build/linux-245f716/include/linux/kconfig.h'
argv[18]='-D__KERNEL__'
argv[19]='-mlittle-endian'
argv[20]='-Iarch/arm/mach-bcm2708/include'
argv[21]='-Wall'
argv[22]='-Wundef'
argv[23]='-Wstrict-prototypes'
argv[24]='-Wno-trigraphs'
argv[25]='-fno-strict-aliasing'
argv[26]='-fno-common'
argv[27]='-Werror-implicit-function-declaration'
argv[28]='-Wno-format-security'
argv[29]='-fno-delete-null-pointer-checks'
argv[30]='-O2'
argv[31]='-marm'
argv[32]='-fno-dwarf2-cfi-asm'
argv[33]='-fno-omit-frame-pointer'
argv[34]='-mapcs'
argv[35]='-mno-sched-prolog'
argv[36]='-mabi=aapcs-linux'
argv[37]='-mno-thumb-interwork'
argv[38]='-D__LINUX_ARM_ARCH__=6'
argv[39]='-march=armv6'
argv[40]='-mtune=arm1136j-s'
argv[41]='-msoft-float'
argv[42]='-Uarm'
argv[43]='-fno-omit-frame-pointer'
argv[44]='-fno-optimize-sibling-calls'
argv[45]='-DCC_HAVE_ASM_GOTO'
argv[46]='-DKBUILD_STR(s)=#s'
argv[47]='-DKBUILD_BASENAME=KBUILD_STR(bounds)'
argv[48]='-DKBUILD_MODNAME=KBUILD_STR(bounds)'
argv[49]='-fverbose-asm'
argv[50]='-S'
argv[51]='-o'
argv[52]='kernel/bounds.s'
argv[53]='kernel/bounds.c'
armv6-rpi36-linux-gnueabi-gcc: error: -mfloat-abi=soft and -mfloat-abi=hard may not be used together
make[3]: *** [kernel/bounds.s] Error 1
make[2]: *** [prepare0] Error 2
make[1]: *** [/home/ymorin/dev/buildroot/O-rpi/build.rpi-tvheadend/build/linux-245f716/.stamp_built] Error 2
make: *** [all] Error 2
Command exited with non-zero status 2
2.51user 0.38system 0:03.55elapsed 81%CPU (0avgtext+0avgdata 44564maxresident)k
0inputs+160outputs (0major+257249minor)pagefaults 0swaps

[Buildroot] EABIhf: breaks kernel build

[Yann E. MORIN]

Thomas, All,

On 2013-07-19 18:17 +0200, Yann E. MORIN spake thusly:
> Since the ARM EABIhf stuff was committed, the Linux kernel build is
> broken, and fails with this message:
>     armv6-rpi36-linux-gnueabi-gcc: error: -mfloat-abi=soft and
>     -mfloat-abi=hard may not be used together
> 
> This is because -mfloat-abi=hard is hard-coded in the wrapper, but the
> kernel wants to pass -msoft-float.
> 
> See attach exerpt of my build log (with a instrumented ext-ttolchain
> wrapper). Notice argv[6] and argv[41]:
> 
>     argv[6]='-mfloat-abi=hard'
>     argv[41]='-msoft-float'
> 
> argv[6] is out hard-coded float ABI option, while argv[41] is passed by
> the kernel.
> 
> I don't know how to solve this.
> 
> The trivial and immediate idea would be to have a black-list of
> arguments and exclude the ones we pass that conflict with the ones
> passed on the command line, but this will be *very* complex and always
> incomplete.
> 
> An alternate idea would be to detect we're building a Linux kernel by
> looking at -D__KERNEL__ in the command line arguments, and if so, not
> pass our hard-coded args. This would work for the Linux kernel, but
> would break for other packages (eg. U-Boot?).
> 
> Another way would be to look at the environment and check if a variable
> is set (eg. BR_IN_KERNEL_OR_UBOOT_OR_WHATEVER) and in this case not pass
> our hard-coded options. While it would work from inside Buildroot, it
> would break as soon as the user would want to use the toolchain directly
> from outside Buildroot.
> 
> Or simply not pass -mfloat-abi=hard at all.

One way which would solve my special case would be to only pass the
sysroot in the wrapper, since my toolchain is already optimised by
default for my target.

So, an option like (give another!):

    config BR2_TOOLCHAIN_WRAPPER_SYSROOT_ONLY
        bool "External toolchain is already optimised for the target"
        help
          Say 'Y' here if your external toolchain is configured to
          emit optimised code for your target.

          If it is not the case, or you are unsure, say 'N', the default.

Then guard the extra hard-coded args between #ifdef...#endif, keeping
only the sysroot arg.

No, this is not the solution at all. But at least it would work when the
external toolchain has been tailored for the target in the first place.

For now, I've just guarded all float-related args between:
    #if defined NOT_DEFINED
    ...
    #endif

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'

[Buildroot] EABIhf: breaks kernel build

[Peter Korsgaard]

>>>>> "Yann" == Yann E MORIN <yann.morin.1998@free.fr> writes:

 Yann> Thomas, All,
 Yann> Since the ARM EABIhf stuff was committed, the Linux kernel build is
 Yann> broken, and fails with this message:
 Yann>     armv6-rpi36-linux-gnueabi-gcc: error: -mfloat-abi=soft and
 Yann>     -mfloat-abi=hard may not be used together

 Yann> This is because -mfloat-abi=hard is hard-coded in the wrapper, but the
 Yann> kernel wants to pass -msoft-float.

 Yann> See attach exerpt of my build log (with a instrumented ext-ttolchain
 Yann> wrapper). Notice argv[6] and argv[41]:

 Yann>     argv[6]='-mfloat-abi=hard'
 Yann>     argv[41]='-msoft-float'

 Yann> argv[6] is out hard-coded float ABI option, while argv[41] is passed by
 Yann> the kernel.

 Yann> I don't know how to solve this.

 Yann> The trivial and immediate idea would be to have a black-list of
 Yann> arguments and exclude the ones we pass that conflict with the ones
 Yann> passed on the command line, but this will be *very* complex and always
 Yann> incomplete.

Yeah, but I think it's the best solution still.

-- 
Bye, Peter Korsgaard