[TF-A] zynqmp: How to inform the bl33 about RAM reservation?

Hi all,

when SPD or DEBUG is enabled, TF-A is moved to RAM on the zynqmp (as it longer fits into OCM). U-Boot happens to avoid that region, but the kernel's DTB has no reservation entry, and Linux will trigger an exception when accessing that region during early boot.

Can we improve this - without requiring the user to manually add a reservation to the DTB? Should we unconditionally reserve 0x1000..0x7ffff in all BL33 DTBs? Or is there a chance to communicate that need? Or some way to detect in BL33 whether it is needed?

Jan