[Buildroot] problem with external toolchain with hard float

[Buildroot] problem with external toolchain with hard float

[Will Wagner]

Hello All,

I'm trying to update a project to 2013.05. I have an external toolchain 
(build with ct-ng 1.18) for arm that is hard float.

The problem I have is that the elf files being built for the target do 
not run. This is because in each elf file the program interpreter is set 
as /lib/ld-linux.so.3 but if I look in the target filesystem that is 
generated it has /lib/ld-linux-armhf.so.3

So it seems like my toolchain is somehow building elf files that won't 
run with the toolchain which has me pretty confused. Do I just need  a 
suitable sym link in my target fs or is this something wrong with how 
things are being built. Could it be that the toolchain wrapper is 
somehow forcing soft float?

Thanks
Will

-- 
------------------------------------------------------------------------
Will Wagner                                     will_wagner at carallon.com
Development Manager                      Office Tel: +44 (0)20 7471 9224
Carallon Ltd, Studio G20, Shepherds Building, Rockley Rd, London W14 0DA
------------------------------------------------------------------------

[Buildroot] problem with external toolchain with hard float

[Patrick Ziegler]

Hi,

Am 04.06.2013 10:47, schrieb Will Wagner:
> Hello All,
>
> I'm trying to update a project to 2013.05. I have an external toolchain (build with ct-ng 1.18) for arm that is hard float.
>
> The problem I have is that the elf files being built for the target do not run. This is because in each elf file the program interpreter is set as /lib/ld-linux.so.3 but if I look in the target filesystem that is generated it has /lib/ld-linux-armhf.so.3
>
> So it seems like my toolchain is somehow building elf files that won't run with the toolchain which has me pretty confused. Do I just need  a suitable sym link in my target fs or is this something wrong with how things are being built. Could it be that the toolchain wrapper is somehow forcing soft float?

If BR2_SOFT_FLOAT is set, the toolchain wrapper adds "-msoft-float" by default. But this option is only available if you build the toolchain with buildroot (or deprecated ct-ng backend)

Best regards
Patrick

-- 
Dipl.-Inf. (FH) Patrick Ziegler

University Of Applied Sciences
Kaiserslautern

Amerikastrasse 1
D-66482 Zweibruecken
Germany

Phone:  +49 631 3724 5526
Mail:   patrick.ziegler at fh-kl.de
PGP KeyID 0xB4796B8C

http://www.fh-kl.de
http://www.fh-kl.de/fachbereiche/imst/iuk-knowhow.html

[Buildroot] problem with external toolchain with hard float

[Will Wagner]

On 04/06/2013 09:47, Will Wagner wrote:
> Hello All,
>
> I'm trying to update a project to 2013.05. I have an external toolchain
> (build with ct-ng 1.18) for arm that is hard float.
>
> The problem I have is that the elf files being built for the target do
> not run. This is because in each elf file the program interpreter is set
> as /lib/ld-linux.so.3 but if I look in the target filesystem that is
> generated it has /lib/ld-linux-armhf.so.3
>
> So it seems like my toolchain is somehow building elf files that won't
> run with the toolchain which has me pretty confused. Do I just need  a
> suitable sym link in my target fs or is this something wrong with how
> things are being built. Could it be that the toolchain wrapper is
> somehow forcing soft float?
>
> Thanks
> Will
>

Hello,

I have sorted my problem, was more a bug with the toolchain ct-ng was 
building. In case anyone else runs into this problem, this is how I 
fixed the issue.

I could work around the problem by settings:

BR2_TARGET_OPTIMIZATION="-pipe -Wl,-dynamic-linker=/lib/ld-linux-armhf.so.3"

The better fix is to patch the building of GCC, see this page with 
details, including patch at the bottom.

https://wiki.linaro.org/OfficeofCTO/HardFloat/LinkerPathCallApr2012

Thanks
Will

-- 
------------------------------------------------------------------------
Will Wagner                                     will_wagner at carallon.com
Development Manager                      Office Tel: +44 (0)20 7471 9224
Carallon Ltd, Studio G20, Shepherds Building, Rockley Rd, London W14 0DA
------------------------------------------------------------------------