The platform callback "validate_ns_entrypoint" does eventually calls platform specific <plat>_validate_ns_entrypoint().
The Arm platforms has its implementation of checking if NS entrypoint lies in either of the
DRAMs.
There are few other platforms which have their own implementation e.g.
- a3700_validate_ns_entrypoint() - Always returns success.
- sunxi_validate_ns_entrypoint() - Similar check as what you asked for
> It will bring dependencies between TF-A and physical memory space which can get
> from uefi atfer memory initialization, if arm_validate_ns_entrypoint() include the
> entire physical memory space.
> In my mind, the kernel should guarantee the validity of entry point.
> So why this check is need?
IMO, the reason for this callback is to have a framework in TF-A to check NS entrypoint , but as i said earlier platform is free to implement whatever it seems enough for it.