The new 'init_platform' function performs the platform-specific
component-local low-level initialization. It allows for the
differentiation between core and regular components as well as
kernel-dependent peculiarities.
This patch introduces a consistent notion of a 'Platform'. Within core,
the 'Platform' contains the kernel-specific initialization. Outside
core, the platform sets up the interplay with the parent component. In
all cases, the platform is constructed while running on the initial
stack.
Issue #4784
When running on x86, and riscv never enter the kernel for cache maintainance,
but use the dummy implementation of the generic base library instead.
On ARMv8 it is not necessary to enter privileged mode for cache cleaning, and
unification of instruction/data cache, but only for invalidating cache lines
at all levels, which is necessary for the use cases, where this function it
needed (coherency of DMA memory).
Fixgenodelabs/genode#4339
