Problems dynamically linking busybox with ppc libs.

[Keith Redfern]

I have just realised that I was barking up the wrong tree in regard to

this issue. 



My problem turned out not to be a issue with compiling/linking Busybox

but that my target was using different libraries to what was specified

in my ELDK. I am a newbie to embedded Linux and now understand that this

is a fundamental step in getting a working system. 



My confusion came about as my ELDK is not a standard ELDK but came as a

BSP from Embedded Planet 852T. Embedded Planet supply a pre-formed

ramdisk image with libraries, Busybox executable, initialisation scripts

etc. 



Any executables supplied in this pre-formed ram disk worked fine. An

initial test of the system showed that Busybox worked fine. 



They have scripts that reverse engineer this to a folder and suggest

just making additions/modifications to this folder and then run another

script to create a new RAM disk image.



I didn't see Busybox packaged with the BSP so I downloaded v1.1.3 from

the web and started working with it, using the ELDK to build. After this

it didn't work. I have now figured out that any new executables built

using the ELDK don't work as they are referencing different versions of

the libraries. The pre-formed busybox worked fine as it was built

referencing the libraries in the also pre-formed library directory.



I don't know why Embedded Planet would have different library versions

in the pre-formed library directory and the ELDK! Maybe there to trick

newbies!



Doing a standard Busybox 'make' with no modifications to the make files

and aligning the target libraries with that provided as part of the ELDK

solved the problem.



Thanks for help on this ......... Keith.



-----Original Message-----

From: Wolfgang Denk [mailto:wd at denx.de] 

Sent: 17 August 2006 10:48

To: Keith Redfern

Cc: linuxppc-embedded at ozlabs.org

Subject: Re: Problems dynamically linking busybox with ppc libs. 



In message

<367F3B3911959C4DA9991C00166F620C1DE208 at EUDUCEX2.europe.ad.flextronics.c

om> you wrote:

> 

> I am trying to dynamically link busybox with the correct libraries

but> 

> run into problems with directory paths and CC/LD flags.



Maybe you do too much?



> I am using the toolchain supplied with ELDK and my target board is

> ppc_8xx based. The busybox version that I am using is 1.1.3.



> I see the following in Rules.mak and have been trying different

variable> 

> options but with no success.



You are not supposed to meddle with Rules.mk. Also, this is not

necessary at all.



> Is this the correct place to make modifications?



No. No modifications are necessary.



Just run a standard configuration  and  make  sure  to  select  cross

compilation with "ppc_8xx-" as Cross Compiler prefix, i. e.:



-> cd /tmp

-> wget http://busybox.net/downloads/busybox-1.1.3.tar.bz2

-> tar jxf busybox-1.1.3.tar.bz2

-> cd busybox-1.1.3

-> export CROSS_COMPILE=ppc_8xx-

-> make config

...

*

* Build Options

*

...

Do you want to build BusyBox with a Cross Compiler?

(USING_CROSS_COMPILER) [N/y/?] (NEW) y

  Cross Compiler prefix (CROSS_COMPILER_PREFIX)

[/usr/i386-linux-uclibc/bin/i386-uclibc-] (NEW) ppc_8xx-

Any extra CFLAGS options for the compiler? (EXTRA_CFLAGS_OPTIONS) []

(NEW)

...

-> make

...

  LINK busybox_unstripped

  STRIP busybox

...



This is so straightforward that I wonder what you moight have done to

run into problems...





> Has anyone already figured the changes required to get this to work

with

> ELDK toolchain?



Yes. And if had bothered to check how the busybox RPM was build which

comes included with the ELDK (for example by  looking  at  it's  spec

file), then you should have known, too.



Best regards,



Wolfgang Denk



-- 

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux

Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de

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