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

Stack guard syntax

I’m trying to set a safe stack guard for stack.
I tried for example with or with out the ?
GUARD_SIZE = DEFINED(guard_size) ? guard_size:0x00000100;

But the ac6 tool chain linker in .ld file report it as an error.
Where can I find the right syntax for stack guard.