Re: [pok-devel] Start a guest binary in a partition

On Wed, May 15, 2013 at 1:34 PM, Philipp Eppelt <philipp.eppelt@xxxxxxxxxxxxxxxxxxxxx> wrote:

Hi,

thanks Julien.

Is there a manual explaining the cross compilation of powerpc and sparc? I have some difficulties setting this up and without it 'make commit' run through.

Also can I just add the Fedora 17 naming for the tools in conf-env.pl? They are different from the ones mentioned there.

Regards,
Philipp

On 05/13/2013 03:15 PM, Julien Delange wrote:

Dear Philip,

From what I see in your patch, everything seems correct and great.
Also, I should probably explain the rationale for having a different
libpok.a for each partition. The initial reason was that we can remove
automatically useless service using compilation macro. Then, we increase
the code coverage, that is really useful for safety-critical
applications that must comply with demanding code coverage standards.

But in your project, it may also makes no sense because this type of
optimization is out of the scope of your project. Thus, you can just
take a generic libpok.a for making a basic example or also just use a
libpok.a with all services (you would have to spot for all POK_USE*
macro to enable them) and include it to build your system.

Also, as you seem very active and willing to contribute, I will give you
access to the repository so that you can commit your changes directly.

Best,

On Sun, May 12, 2013 at 5:24 PM, Philipp Eppelt
<philipp.eppelt@xxxxxxxxxx-dresden.de
<mailto:philipp.eppelt@mailbox.tu-dresden.de>> wrote:

Hi,

I can only find libpok/libpok.a. As libpok.a is generated for every
partition I think it would be nice, if it resides in the partitions
directory in generated-code/cpu/partX/ to save it from being
overwritten by the libpok.a for the next partition.

For the project it is essential, as several RTEMS instances with
different needs and other partitions should be running in the system
(one day).
However, I don't know if any constraints apply to the
generated-code/ directory, preventing libpok.a to reside in the
partX/ dir.

I modified misc/mk/rules-partition.mk <http://rules-partition.mk> to

copy the current libpok to the current partition directory. The
patch is attached and I hope its accurate.
It worked for example/partitions-threads/.

Regards,
Philipp

On 05/12/2013 06:00 AM, Julien Delange wrote:

Hi,

As far as I remember, POK builds a library that is then linked
with the
code. For each partition, it builds a libpok.a tailored
according to the
requirements of the partition. Then, you would need to link the
libpok.a
of the partition to your RTEMS instance.
Also, I think the approach and your design seems to be clean.
This is
good because most of the time, along the project, we use some
hacks and
other tricks to address some problems/issues we do not expect. Then,
starting with a good design in mind is a good start :-)

On Fri, May 10, 2013 at 11:16 AM, Philipp Eppelt
<philipp.eppelt@xxxxxxxxxx-__dresden.de
<mailto:philipp.eppelt@mailbox.tu-dresden.de>
<mailto:philipp.eppelt@__mailbox.tu-dresden.de
<mailto:philipp.eppelt@mailbox.tu-dresden.de>>> wrote:

Hi,

yes Wiktor used a combine script to build partition.bin,
sizes.c and
to compile pok.elf again. This looks like
misc/mk/rules-main.mk <http://rules-main.mk>
<http://rules-main.mk>.

My approach still utilizes this script to fuse everything
together.

I wrote about it in the RTEMS wiki [0] and here it is:

* Design the POK system via an AADL model.
* Keep the size of the final binary, including RTEMS, in mind.
* Build the POK container for the RTEMS code --> Library
* Take the library and pass it to RTEMS at compile time.
* Use the last years pok_rtems_combine script to add the final
binary as partition.

This is a clean approach on both sides. POK will be
configured with
the AADL model and the partition binary implements the POK
side of
the communication interface. As POK starts partitions by
loading the
ELF-binary and jumping in on the entry_ip specified in the
ELF-header, RTEMS should start fine. On the RTEMS side the
use of
the virtualization layer functions works without issues, as the
function implementations are passed via the library.

Is it possible to tell the tool-chain to build a library file?
When the elf is loaded the entry_IP is saved in the
pok_partitions
array and my guess is, it is used to start the binary. But
how does
the AADL subprogram source_name property play into this?

What do you think of this approach?

Regards,
Philipp

[0]
http://wiki.rtems.org/wiki/____index.php/GSOC_2013_-_____Paravirtualization_of_RTEMS#____Build_process
<http://wiki.rtems.org/wiki/__index.php/GSOC_2013_-___Paravirtualization_of_RTEMS#__Build_process>

<http://wiki.rtems.org/wiki/__index.php/GSOC_2013_-___Paravirtualization_of_RTEMS#__Build_process
<http://wiki.rtems.org/wiki/index.php/GSOC_2013_-_Paravirtualization_of_RTEMS#Build_process>>

On 05/04/2013 06:16 AM, Julien Delange wrote:

Hi,

Indeed, the binaries are concatenated with the kernel
to built the
binary to load on the target. As far as I remember,
this was
also the
approach used by the student last year but it was done
manually (not
integrated with the actual toolchain). If you want to
break, you
need to
know the address in RTEMS + the start address of the
partition.
That is
why in the POK debug mode (as far as I remember), we
show the start
address of a partition. Then, you should be able to put
your
breakpoint.

Please ask other question if you need. I am no longer
developing
POK but
I hope that actual (anybody from owi, tpt ?) and old
(Laurent ?)
developers would help so that we might be able to
design a first
draft
of proof of example of POK as an RTEMS virtualisation
layer. On
my side,
I will do my best to answer the rest of knowledge I
have :-)

On Fri, May 3, 2013 at 6:17 AM, Philipp Eppelt
<philipp.eppelt@xxxxxxxxxx-____dresden.de
<mailto:philipp.eppelt@mailbox.tu-__dresden.de>
<mailto:philipp.eppelt@__mailbox.tu-dresden.de
<mailto:philipp.eppelt@mailbox.tu-dresden.de>>
<mailto:philipp.eppelt@
<mailto:philipp.eppelt@>__mailb__ox.tu-dresden.de
<http://mailbox.tu-dresden.de>

<mailto:philipp.eppelt@__mailbox.tu-dresden.de
<mailto:philipp.eppelt@mailbox.tu-dresden.de>>>> wrote:

Hi,

I tried to inject an RTEMS binary into POK.
By modifying the generated-code/cpu/Makefile to
use hello.exe
(RTEMS) as partition binary instead of
part1/part1.elf and I
introduced a makefile rule just depending on
$(TARGET), so the
partitions and kernel aren't rebuild.

Result:
partitions.bin -> nm shows the RTEMS symbols
sizes.c -> contains the size of hello.exe

make run spins in a reload cycle.
However, I did at least expect the binary to be
loaded, but
I didn't
manage to confirm this with make run-gdb. It behaves
strange, as
breakpoints are accepted but the execution won't
stop at
the defined
breakpoint. Sometimes it does after various tries and
symbol-file
switches.

Do you have some recommendations to solve this gdb
issue?
Or an idea how I can confirm the successful
loading of the
hello.exe
binary?

Regards,
Philipp

On 05/02/2013 07:39 PM, Philipp Eppelt wrote:

Hi,

I am a student at Dresden University of
Technology,
currently
applying
to Google Summer of Code for the RTEMS project.

The purpose of my project is to design and
implement a
paravirtualization layer in RTEMS to ease
virtualization. As
proof-of-concept I like to use POK as host system.

In last year's GSoC a student used POK to run
RTEMS
with the
goal to get
RTEMS ARINC 653 compliant.
He introduced new syscalls to POK and combined the
RTEMS partly
linked
.ralf file with the POK binary. He used cat to
pipe both
binaries into
the same file and used some 'magic' to fuse
the two
systems.
However, none of the usual tools (nm, readelf,
objdump)
read the
resulting binary correctly, therefore I
refrain from
taking this
way.
Additionally, I don't want to use direct
syscalls from the
guest, as the
virtualization layer in RTEMS should be portable.

Now I am searching for a way to start the
RTEMS guest
binary.
My first idea was to build an application in POK
containing all
'guest
communication functions' (e.g. disable/enable
interrupts, console
access) and to pass the fully linked file as a
library
to RTEMS.
Then
the RTEMS build process would run without
errors, as
the missing
function implementations are provided.
But I don't know, how I can call the RTEMS
bsp_start()
function for
instance, as POK doesn't know about this at
compile time.

The second idea was to build RTEMS first. This
will
fail due to
undefined references cause by the 'communication
functions'. The
partly
linked .ralf file could then be inserted while
POK is
linked,
resolving
the undefined references. This is pretty much the
approach of last
year's student. But that would intercept with
the build
process
of POK
and is therefore no satisfying approach. An custom
linker script
might
resolve the issues with the tools, though.

So I am a little stuck here and seeking guidance.
Do you have another idea?
Is there some source code supporting foreign
binaries to be
executed in
a partition?
Do you know of projects doing something similar?

Regards,
Philipp