[uClinux-dev] Compile/Run Problems in uClinux (m68knommu, Coldfire)

[Wolfgang Wegner]

Dear list,

I hope I am on the right track here...

I am having serious problems getting a program to compile and run
in uClinux. Platform is m68k-nommu (MCF5373L, actually).

What I have:
- A complete development environment from Emlix (came with a
  senTec COBRA5329 board), using m68k-elf-gcc (GCC) 3.4.3 (Emlix Linux 3.4.3-6)
- from the same package:
  uClinux-dist-emlix-1.1.tar.bz2
  (contains uClibc 0.9.27, linux 2.6.17-uc0)
- uClinux-dist-20070130 from the m68k port page of uClinux.org, patched with
  uClinux-dist-20070130-20071017.patch.gz

What I can get:
- if I configure and compile manually, I get a running kernel from both
  uClinux-dist versions
- if I compile manually with these flags:
CC = m68k-uclinux-gcc
CPPFLAGS = -I$(TOP)/include -I/usr/include
CFLAGS = -Wall -m5307
LDFLAGS = -Wl, -elf2flt="$(FLTFLAGS)" -m5307
LDLIBS = -lpthread
FLTFLAGS = -s 262144
  I get simple executables that work under my self-compiled kernel.
  (However, with some bad limitation - see below...)

What does not work:
- using threads with libpthreads in my application. Calling pthread_create
  simply stops all execution (of course, the binary is statically linked).
- compile either distribution of uClinux. The Emlix one once compiled, but
  now I get :
lib/libc.elf2flt(.text+0x2d966): In function `__do_global_ctors':
../../gcc/libgcc2.c:1623: undefined reference to `atexit'
collect2: ld returned 1 exit status
make[2]: *** [lib/libc] Error 1
make[2]: Leaving directory `/projects/local/uClinux-dist-test/uClibc'
  Honestly, I do not know what I did to break it...
- compile the kernel from within uClinux-dist
  When I try to compile the kernel from within uClibc-dist, the kernel
  quietly does not run - or I do not see it is running? No idea...
  I did not yet really figure out how to debug a kernel, so I do not
  know what is happening there, I simply do not get any console output
  after starting it from the bootloader. Compiling manually from the
  same tree gives a working kernel.
- run any binary from the Emlix uclinux-dist-test under my self-compiled
  kernel - when starting it as the init process, I get something like
  "mmap failed" and the kernel barfs because it can not start init.
- compile the newer uCinux-dist; I always get linker errors like
thdm.elf2flt(.text+0x7cbe):__cxa_atexit.c: undefined reference to `__preinit_array_end'
thdm.elf2flt(.text+0x7cde):__cxa_atexit.c: undefined reference to `__init_array_start'
thdm.elf2flt(.text+0x7ce2):__cxa_atexit.c: undefined reference to `__init_array_end'
thdm.elf2flt(.data.rel+0x4304): undefined reference to `_errno'
thdm.elf2flt(.data.rel+0x430c): undefined reference to `_h_errno'
collect2: ld returned 1 exit status
make[3]: *** [thdm] Error 1
make[3]: Leaving directory `/projects/new/uClinux-dist/user/threaddemos'

My problem is I do not really understand the make system of uClinux-dist.
Why is there a difference if I compile from within uClinux-dist or by
calling make ARCH=m68knommu CROSS_COMPILE=m68k-uclinux- by hand?

My questions:
- Can anybody give a hint why there is a difference between compiling
  the kernel manually or from within uClinux-dist?
- can anybody give a hint why the newer uClinux-dist is not compilable
  and gives the above linker error? Is it a compiler version problem?
  If so, which compiler/binutils should I use? I wanted to try crosstool,
  but they do not support uClibc, so it seems I have to do this by hand.
- Is the problem with threads not running related to the way I do the
  compilation (and thus why uClinux-dist binaries do not run under my
  own kernel)?

Sorry for the long text - in case anybody made it up to here: thank you,
any hints or comments are most welcome!

Best regards,
Wolfgang