[ECOS] Re: Different section placement for kernel and application

[Grant Edwards <grant.b.edwards@gmail.com>]

On 2011-01-27, Martin R??sch <martin.roesch@neratec.com> wrote:

> I'm trying to figure out how to run the eCos kernel from ROM and run
> the application (the main() function) from RAM on the STM32 Eval
> Board. Is it possible to place the text, data and rodata sections
> from the target library to a different memory address (i.e. flash)
> than the sections of the application in the image?

No, that's not possible in any general/useful sense without major
changes to the way eCos is designed and built.  

The way eCos is built there is no logical separation between the
kernel and the application.  They're both just C/C++ functions that
are linked together to form a single executable ELF file.

In theory, you could apply section attributes to all of the kernel
functions (or all of the application functions) so that you could
separate them at link time into different output sections.  But, that
wouldn't really be useful, since the linkage between the two output
would require that they always be updated together in the target
board.

I _suspect_ what you're really asking about is some sort of
position-independent API between kernel, libraries, and application so
that you can update one without updating the others -- something akin
to the Unix syscall API or the Unix shared library mechanism that
allows kernel, application, and libraries to be changed independently.

-- 
Grant Edwards               grant.b.edwards        Yow! Is this going to
                                  at               involve RAW human ecstasy?
                              gmail.com            


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