SW4STM32 and SW4Linux fully supports the STM32MP1 asymmetric multicore Cortex/A7+M4 MPUs

   With System Workbench for Linux, Embedded Linux on the STM32MP1 family of MPUs from ST was never as simple to build and maintain, even for newcomers in the Linux world.
And, if you install System Workbench for Linux in System Workbench for STM32 you can seamlessly develop and debug asymmetric applications running partly on Linux, partly on the Cortex-M4.
You can get more information from the ac6-tools website and download two short videos (registration required) highlighting:

System Workbench for STM32

serious bug. cubeMx generation issue under C++

Ah, they already do include this (I use C++ in CubeMX projects right now - as in today).

You will however find life much easier if you confine yourself to naming C++ _exclusive_ headers to *.hpp (or similar)
There are several posts here about converting a project to C++