Generated `regions.h` and linker scripts are not aligned

[ReinhardKeil]

Describe the problem

The CMSIS-Toolbox auto-generates regions.h files and provides linker scripts in the etc directory as described here: https://github.com/Open-CMSIS-Pack/cmsis-toolbox/blob/main/docs/build-overview.md#linker-script-management

However the two files are not aligned. The problems are:

• Symbols xxx_DEFAULT, ROMx_STARTUP, RAMx_INIT are generated in regions.h but not used in linker script.
• Linker script contains region RAM0..3 and ROM0..3, however the regions.h file may contain more regions as each memory defined in the DFP/BSP is mapped into a region.
• Linker script region ROM0 contains vector table for startup - there is no flexibility in the script itself.
• Linker script region RAM0 contains uninit sections - there seems to be no special handling required.

It is unclear how RAM_INIT should be handled by a linker script itself.

To Reproduce See https://github.com/Open-CMSIS-Pack/STM32F746G-DISCO_BSP/tree/main/Layers/IoT/RTE/Device/STM32F746NGHx

Suggested behavior

Changes to auto-generated regions.h:

• Do no longer generate the symbols xxx_DEFAULT, ROMx_STARTUP, RAMx_INIT
• Add for ROM0 a comment that this is the startup region
• Add for RAM0 a comment that this contains uninitialized memory, STACK and HEAP
• As ROM0 is the startup region it should get the first memory from DFP/BSP that has the attribute startup set.
• Combine contiguous memory from BSP/DFP into one region
• Exclude memory from BSP/DFP that has attribute default=0 or Pname instead:
  • List memories with attribute Pname or default=0 in comment section (user may manually add it).

Once the files are generated/imported to the project they are under user control. Therefore the suggested behavior has acceptable user impact.

Environment (please complete the following information):

• CMSIS-Toolbox Version 2.5.0

Additional context It is unclear if and how init should be handled in linker scripts.

IMHO, there should be a resource management added to CMSIS-Toolbox that can deal with multi-core systems and applications that require bootloader/application/secure enclave.

[ReinhardKeil]

Proposed changes:

DONE ALREADY: 1. Remove the defines HEAP and STACK from the linker script templates (as they are also in the regions.h files).

2. regions.h file example: regions_B-U585I-IOT02A.h.txt. Changes are:
   • Always 4 regions for ROM and RAM generated.
   • Resources are combined when (a) same access, (b) same pack, (c) directly after each other. Example see RAM0 region.
   • Resources that have default 0 or a different Pname then the current project are under "Resources that are not allocated to linker regions".
   • Comment text uses less lines, adds 'access' information from PDSC

This is how it looks in Config Wizard view