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 (registration required) various documents highlighting:

System Workbench for STM32

Build Errors with STM32L476 Discovery Board

Last week I was at a ST seminar where we built and ran several projects on the STM32L476 Discovery board.

I used:
System Workbench (latest)
CubeMX 4.11
L4 HAL 1.1.0
ST-Link Utility 3.7.0

The simplest example using CubeMX is:
1 - Create new project. Select STM32L476VGTx (LQFP-100, 1024K Flash)
2 - Left-click PB2 & PB8 and set to GPIO_Output mode (these are the user LEDs on the board)
3 - Open Project->Settings and give the project a name and location. Select SW4STM32 as the toolchain.
4 - Generate the code.
5 - Import project into System Workbench. Open main.c and scroll to the bottom.
6 - Within “USER CODE BEGIN WHILE” / “USER CODE END WHILE” add to the while loop:
7 - Save, Build.
8 - Debug As “AC6 STM32 C/C++ Application” and specify the target as ST-LinkV2-1 with SWD connection.

Admire the blinking lights.