On Fri, 14 Oct 2011, Russell King - ARM Linux wrote:

But... one thing to note is that it _is_ common to load the decompressor
at a _different_ address to that where the kernel ultimately ends up
residing to avoid the additional copy in the decompressor.  My experience
shows that this is quite common on the platforms I had supplied.  This
means that if we default to AUTO_ZRELADDR for !ZBOOT_ROM, we end up
having to have developers change their uboot setups to avoid unexpected
results.

Currently, U-Boot insists on having a uImage with a fixed absolute load 
address.  This is currently provided by the zreladdr value, whether or 
not AUTO_ZRELADDR is set.  I consider this as a persisting uImage 
limitation.

Either u-Boot gets fixed so it can work with plain zImage (and this 
certainly will happen once the pressure from people wanting a single 
kernel to work on targets with different load addresses increase.  
Tegra is one such example.

Or we create a u-Boot specific Kconfig menu for uImage options that 
would be common to all architectures and kick it out from the ARM 
specific makefile.  This is not solving the u-Boot limitation though.

In either cases this is a u-Boot problem that needs fixing on the u-Boot 
side in the end.


Nicolas