Feature Request: "no-init" linker section

[Andrew Neil]

It is a common requirement to have an area of RAM that is not cleared or otherwise initialised by the startup code; eg,

https://community.st.com/t5/stm32cubeide-mcus/how-to-make-keep-ram-value-after-software-reset/m-p/96132

https://community.st.com/t5/stm32cubeide-mcus/how-to-port-no-init-iar-directive-with-to-gcc-compiler-please/m-p/661867

to mention but two.

Currently, this means making manual edits to the linker script - which get overwritten with every 'Generate'. ☹️

So how about adding a "noinit section" option in the Project 'Linker Settings':

Or making the generated linker script have areas which will not get overwritten - as in the generated 'C' code.

(I've tagged this as 'Bug Report' because the forum insists on having a tag, but none of the available tags is relevant! 'Bug Report' seems the least worst.)

[Pavel A.]

> Or making the generated linker script have areas which will not get overwritten

Maybe easier and faster can be to write a KB article about implementing a no-init RAM section. This not necessarily can be a piece of the "main" RAM. Some STM32s have the backup RAM, or several SRAM units that are not referenced in the "standard" link script. These can be used for no-init data as well.

[Radosław]

I'm waiting many years to have posibility to define new section and menage them  in MX or IDE.

[Pavel A.]

Manage sections in a GUI? Do you mean, a GUI for GNU ld scripts? This is possible, as an Eclipse add-on.

You can propose this in the common Eclipse CDT forum, even sponsor this idea to show your motivation and support.

A simpler variant can be like the linker option dialogs in Keil MDK and IAR IDE: a couple of input fields, like ROM1, ROM2, RAM1, RAM2... address & size, with "no init" check boxes. These fields generate defined symbols prepended to a common link script with conditional ifdef's. ... and so on.

[Radosław]

Done by many people In many ways,  Compatitors creates this long time ago. 

I have my own solution for this :D

[Andrew Neil]

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@Andrew Neil wrote:

Currently, this means making manual edits to the linker script - which get overwritten with every 'Generate'. ☹️

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Actually, it seems that's not true - 'Generate' does not (necessarily?) overwrite the linker script.

[BarryWhit]

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@Radosław wrote:

I'm waiting many years to have posibility to define new section and menage them  in MX or IDE.

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For the newer STM32U5 family (at least), they seem to be moving in that direction:

[Radosław]

This is for cortex M33 to configure secure and non secure regions.

But for all STM32 should be posibility to define memory regions, and sections.

In CMSIS startups  provide posobility to initialize or clearing multiple sections.  It not hard do generate proper linker script  from MX.

I personally don't use MX, So i create  linker script from configuration file by preprocessor.

Very often I need section located just after vector table.

There only few things are nessesary. 

1. name of section

2, memory region for LMA address

3, memory region for VMA address.

4. defining is this section is  Initialized, zero or no init

5. adding  NOLOAD 

6. adding  KEEP

[BarryWhit]

My point is that ST has already (for some families) implemented a GUI for editing memory sections that drives linker script generation - so what Andrew (or your own thread hijacking feature request) is asking for is a natural extension of something that already exists, not a complete rewrite of their flow.