Re: Can not build flat shared library.

[Gary Altenberg <gary at ioengineering dot com>]

On 3/14/2011 6:14 PM, Yann E. MORIN wrote:
> Gary, All,
>
> On Monday 14 March 2011 22:52:21 Gary Altenberg wrote:
> > I am attempting to build a tool chain for an ARM (no mmu arm7tdmi) to
> > build applications for a uClinux board. I read that I should use a
> > shared library so I set my "Target File Format" in uClibc to Shared
> > FLAT. It says in the help for Shared FLAT to "Pick this one if you are
> > using uClinux and wish to build uClibc as a flat-format shared library".
> > Are there options in gcc to pick this also? I didn't see any.
> I believe we do not currently have proper support for flat binaries.
> You should have a look at:
>    scripts/build/kernel/linux.sh
> in function CT_DoKernelTupleValues:
>
>    CT_DoKernelTupleValues() {
>        if [ "${CT_ARCH_USE_MMU}" = "y" ]; then
>            CT_TARGET_KERNEL="linux"
>        else
>        # Sometime, noMMU linux targets have a -uclinux tuple, while
>        # sometime it's -linux. We currently have only one noMMU linux
>        # target, and it uses -linux, so let's just use that. Time
>        # to fix that later...
>        #    CT_TARGET_KERNEL="uclinux"
>            CT_TARGET_KERNEL="linux"
>        fi
>    }
>
> So in your case, I guess you'd want a tuple that ends with -uclinux instead
> of -linux. Care to test that (override in the script)? If it works, then it
> will be time to review that function and be a bit more inventive there.
>
> Also, in the binutils sub-menu, you will have to choose one of:
> - 'Flat' and a version of elf2flt,
> - 'FD_PIC ELF'
>
> Note: AFAICR, the "only one noMMU linux target" referred-to in the linux
> kernel script, above, is blackfin.
>
> Regards,
> Yann E. MORIN.
Yann,

I un-commented the CT_TARGET_KERNEL="uclinux" and attempted to build. I 
did not use FD_PIC ELF but just flat and elf2flt.

In the log file I now get:

 gtyp-input.list:15: file 
/work/arm-tools/targets/src/gcc-4.3.1/gcc/config/arm/uclinux-elf.h 
specified more than once for language (all)

By the way when I build using the original configuration I sent you the 
tools build just fine and I can build and run uClinux on my ARM 
hardware. I was having problems with the applications but I am able to 
get some working. I even got the miniupnpc library to work in my 
application. I just can't seem to get busybox and most of the 
applications that are in uClinux distribution to work. I keep getting:

Unhandled fault: vector exception (0x800) at 0x00000000
SIGSEGV

In the case of miniupnpc it was using a -fPIC option that I removed and 
I also put in -march=armv4t and -mtune=arm7tdmi and now it runs. I tried 
that with busybox with no luck yet.

So what benefit will there be in having CT_TARGET_KERNEL set to uclinux?

Regards,
Gary

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