[ELDK] gdbserver issues on xilinx PPC440 Virtex5FX with ELDK4.2

[Frederic LEGER]

Hi Wolfgang,

Indeed, GLIBC is preferred in our developments, that's why we are using ELDK
4.2. 
We are using two Linux computers, one under Ubuntu Ibex 32bits, second under
Ubuntu Ibex 64bits.

History
------- 

First tries were with ELDK 4.2 GLIBC ramdisk.image.gz (1.8Mo) + gdbserver
and libs + hello app => crash on break main when "continue" => continuing...
Libs were added after using ${CROSS_COMPILE}ldd against gdb and gdbserver
and comes from the ppc_4xx \libs and \usr\libs drawer.
We tried kernels 2.6.28, 2.6.27rc4 and 2.6.27rc9 from Xilinx git.

Next try with ELDK4.2 GLIBC ramdisk.image.gz (1.8Mo) + GDB and libs + hello
app  => crash on break main & continue.
Ext2 ramdisk size was 16Mo cause GDB and libs are quite heavy. (we have 64MB
soldered on board)
We tried kernels 2.6.27rc9 from Xilinx git.

Next try with Buildroot2009rc4 rootfs including GDB and gdbserver + hello
app  => crash on break main & continue. Everything cross-compiled with
Buildroot excepting Linux kernel built with ELDK4.2.

Next try with ELDK4.1 UCLIBC ramdisk.image.gz + gdbserver and libs + hello
app  => crash on break main& continue.
We tried kernels 2.6.27rc9 from Xilinx git.
 
Next try with ?stable? Buildroot2009-02 rootfs including GDB and gdbserver +
hello app  => crash on break & continue. Everything cross-compiled with
Buildroot against 2.6.28 headers including the kernel 2.6.28.
We tried kernel 2.6.27rc9 also.

Could you please give me your opinion on the behaviour below :  

${CROSS_COMPILE}gdb --tui helloppcstatic Then under gdb: target remote
172.20.20.3:5678 

Now, after connecting to target I got:
Remote debugging using 172.20.20.3:5678
0x10000140 in _start()
(gdb)

Then if I use 'c' => program ends up correctly on the target.
Hello World !
Hello World Again !
Still Hello World !
....
GDBserver exiting


If I use step => first step to 0x10000630 in __libc_start_main() => crash on
the second time within function __libc_start_main.

If I add one or more breakpoints (ie: break *main , break 5) and then 'c' =>
crash target keeps "continuing..."

If I add a breakpoint (ie: break *main) and then 'continue' => crash 
(gdb)Break main 
Breakpoint 1 at 0x100002b8: file hello.c, line 5.
(gdb)continue
=> output nothing more, target keeps "continuing..."


Best regards,

Frederic


-----Message d'origine-----
De : Wolfgang Denk [mailto:wd at denx.de] 
Envoyé : mardi 24 février 2009 13:00
À : Frederic LEGER
Cc : eldk at lists.denx.de
Objet : Re: [ELDK] gdbserver issues on xilinx PPC440 Virtex5FX with ELDK4.2

Dear Frederic,

In message <001501c99657$84e45f10$3e0414ac at esisar.inpg.fr> you wrote:
> 
> Just to tell you that I used ELDK4.1-UCLIBC with 2.6.27-rc9 with same 
> crazy behaviour.
>
> I also used latest stable Buildroot 2009.02 with GCC4.3.2, latest 
> uclibc etc... Etc... With kernel 2.6.28 from xilinx git tree : same 
> result, GDB on the target is crashing after setting a break point and
"continue".

The "GCC4.3.2, latest uclibc" part scares me.

You mean you are NOT using the ELDK provided target environment, which
- among other things - contains the libraries that were used to
  configure and build GDB abd gdbserver for the target?

> The problem exists with the GDB on the target, and by extension with 
> GDBSERVER also.

Hm...

Please try:

1) using a *clean* ELDK root file system environment, i. e. ONLY the
   tools and libraries that come with the ELDK.

2) use a glibc based invironment instead of uclibc (which  is  always
   good  for  some  nasty surprises, without compensating this by any
   significant benefits).

Best regards,

Wolfgang Denk

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