[okl4-developer] Hello world on arm926ejs....

[Peter Howard]

On Wed, 2008-11-12 at 18:28 +0100, Hugues Balp wrote:
> Hello everybody,
> 

Hello Hugues

> I first want to thank you for the good job that has been made around the 
> OKL4 micro-kernel.
> I' ve just registered to this mailing list after having downloaded OKL4 
> v3.0 and
> performed some installations and tests with the hello world example for 
> arm926ejs targets...
> 
> Nevertheless  I encountered a number of problems during installation and 
> compilation phases....
> So I have now a number of questions and hope you will help me to 
> understand what happens
> on my system...
> 
> The first target I wanted to test is called versatile ( with an 
> arm926ejs processor ).
> 
> So following the instructions of the OKL4 wiki, either in Prerequisite 
> page as in the one
> dedicated to the release 3.0, I have downloaded first the precompiled 
> SDK for arm926ejs
> target so as the arm-linux crosstool proposed in URL
>     http://www.ertos.nicta.com.au/downloads/tools/arm-linux-3.4.4.tar.gz
> 

This toolchain is out of date.  You need to build your own toolchain via
crosstool as described on http://wiki.ok-labs.com/Release/3.0  (though I
gather from comments below that you have already done that).

> After some installation steps I got the following error when trying to 
> compile as follow
> the singlecell example delivered within the sdk:
> 
>     cd $OKL4_SDK_ROOT/okl4/arm926ejs/examples/singlecell
>     make clean
>     make
> 
> The complete listing of the error is joined to this mail.
> The error deals with* internal relocation errors* due to 
> incompatibilities between binary libraries *ABI versions* as described below
> 
> "ERROR: build.micro-debug/src/hello.o is compiled for EABI version 0, 
> whereas build.micro-debug/bin/hello is compiled for version 4"
> 
> What is amazing is to observe that ABI versions differ within the 
> supplied precompiled sdk-arm926ejs itself, as illustrated by the
> following commands:
> 
>     cd $OKL4_SDK_ROOT
>     find . -name "*.o" -exec ls {} \; -exec readelf -h {} \; | egrep 
> "Flags|arm926ejs"
>     ./kernel/arm926ejs/micro-debug/object/arm926ejs.o
>       Flags:                             0x200, GNU EABI, software FP
>     ./kernel/arm926ejs/micro-debug/object/versatile.o
>       Flags:                             0x200, GNU EABI, software FP
>     ./kernel/arm926ejs/micro-debug_no_console/object/arm926ejs.o
>       Flags:                             0x200, GNU EABI, software FP
>     ./kernel/arm926ejs/micro-debug_no_console/object/versatile.o
>       Flags:                             0x200, GNU EABI, software FP
>     ./kernel/arm926ejs/micro-benchmark/object/arm926ejs.o
>       Flags:                             0x200, GNU EABI, software FP
>     ./kernel/arm926ejs/micro-benchmark/object/versatile.o
>       Flags:                             0x200, GNU EABI, software FP
>     ./kernel/arm926ejs/micro-production/object/arm926ejs.o
>       Flags:                             0x200, GNU EABI, software FP
>     ./kernel/arm926ejs/micro-production/object/versatile.o
>       Flags:                             0x200, GNU EABI, software FP
>     ./kernel/arm926ejs/micro-tracebuffers/object/arm926ejs.o
>       Flags:                             0x200, GNU EABI, software FP
>     ./kernel/arm926ejs/micro-tracebuffers/object/versatile.o
>       Flags:                             0x200, GNU EABI, software FP
>     ./okl4/arm926ejs/micro-debug/libs/crt0.o
>       Flags:                             0x4000000, Version4 EABI
>     ./okl4/arm926ejs/examples/singlecell/hello/build.micro-debug/src/hello.o
>       Flags:                             0x200, GNU EABI, software FP
>     ./okl4/arm926ejs/micro-production/libs/crt0.o
>       Flags:                             0x4000000, Version4 EABI
>     ./okl4/arm926ejs/nano-production/libs/crt0.o
>       Flags:                             0x4000000, Version4 EABI
>     ./okl4/arm926ejs/nano-debug/libs/crt0.o
>       Flags:                             0x4000000, Version4 EABI
> 

This is intentional.  At this point in time the OKL4 kernel itself is
built to an older EABI standard, whereas the user-space code is built to
EABI-v4.


> Another thing that I don't understand in the above error message comes 
> from the fact that
> the file build.micro-debug/src/hello.o  is really a binary object file,
>     as illustrated by the following "file" command output:  ELF 32-bit 
> LSB relocatable, ARM, version 1, not stripped
> whereas the item build.micro-debug/bin/hello isn't really a file.
> Indeed the only file that resides in directory 
> $OKL4_SDK_ROOT/okl4/arm926ejs/examples/singlecell/hello/build.micro-debug/bin
> is an XML file named hello.xml.
>    So I imagine there is a binary file generated from this XML file ? I 
> that true ?....
> 
> Another thing to add is that the error is the same either when I use the 
> arm-linux toolchain referenced in the OKL4 wiki Prerequisite page
> or with a self compiled crosstool chain with support for eabi ( as 
> documented in the mailin-list archive ).

Just to clarify - the toolchain you built is crosstool 0.43 with OKL's
EABI patch?  Looking at your crosstool config file I think not, as it
shows you building with gcc 3.4.5 whereas it should be using gcc 4.2.4

The example builds with our "internal" toolchain.  I'm doing a scratch
rebuild of crosstool from the wiki to confirm that we haven't stuffed
anything up there.  I'll post a followup when it's built.

> You can also refer to the joined configuration file of this toolchain.
> 
> To sum up I am just wondering me how I can get rid of this problem ?
> 
> I will send to you later other questions around the compilation of OKL4 
> itself and its required crosstool chains....
> 
>     Thanks in advance for your help,
> 
Hoping my help helps.

-- 
Peter Howard <peterh at ok-labs.com>