[U-Boot-Users] booting elf images from flash

Wolfgang Denk wd at denx.de
Mon Mar 21 09:30:14 CET 2005

Dear Robin,

in message < at ptg1.spd.analog.com> you wrote:
> The problem is after we make a distribution and fix the load points in SRAM 
> - it limits the ability for end users to add or swap out our drivers 
> without having to touch the source. It makes kernel config almost 
> impossible for specific driver combinations.

This is a kernel design problem.  And  yes,  it  is  a  problem.  But
strictly  speaking  this  is off topic here. You should solve this in
the Linux kernel environment.

> If the linker handles it, the user only finds out if there is a problem 
> with things if there is too much code allocated for SRAM.

Yes - but again, this only affects LInux, right?

> >objcopy should be capable of doing this - even if you probably  don't
> >like the result ;-)
> It does actually error - with "File size limit exceeded"

I see. Maybe we should build it with LFS enabled :-)

> >U-Boot already understands how to deal with  ELF  images.  It's  just
> >that  we  don't  use  ELF images for the Linux kernel, as there is no
> >need to do so, and no advantages (but several disadvantages).
> I would be interested in your thoughts of why booting elf images is a 
> disadvantage. We do it all the time, and have not run into any problems.

Bigger images, slower boot times, bigger U-Boot image.

> >Just assume that some other boot loader will be used to
> >boot your Linux kernel images.
> the only boot loader that we support right now - is U-Boot, and the on-chip 
> ROM bootloader (which also boots elf images)...

Other users might want to use other boot loaders...

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
Q: Why do PCs have a reset button on the front?
A: Because they are expected to run Microsoft operating systems.

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