Fix arm-none-eabi-ld: warning: /github/workspace/sources/nuttx/nuttx has a LOAD segment with RWX permissions

[xiaoxiang781216]

Report from all ci console, like this:
https://github.com/apache/nuttx/actions/runs/7347758008/job/20004759931

[pkarashchenko]

I'm not sure how to fix this especially when the part of the code is relocated to SRAM.

[codusnocturnus]

Just getting into this level of development, and am only working with STM32, so I can't say it's an all-around fix with no edge cases, but the solution on this blog seems to work: Solution to LOAD segment with RWX permissions warning with CMSIS

To summarize, define a PHDRS block in the linker script with descriptions for the text, data, and bss segments, and assign the segments to the related output sections.

The warning goes away, and the ELF listing will show that the flags on segment 0 are now "correct".