Example locating interrupt and main stacks in DTCM

[DerekSnell]

The attached example uses a linker script to place the pinned linker sections in DTCM. This includes the z_interrupt_stacks and z_main_stack. On the NXP i.MX RT SOCs, this can increase the performance substantially compared to leaving in the default external SDRAM.

The example is tested on the mimxrt1170_evk//cm7 board, and built with Zephyr v4.0.0.

pinned_hello_world.zip

[DerekSnell]

Marking as answered

[ofirshe]

Hey @DerekSnell,
I've tried applying this enhancement to the mimxrt1060_evk board but encountered a compilation error during the build process:

c:/users/ofirs/bsp/zephyr-sdk-0.16.8/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd.exe: zephyr/libzephyr.a(cbprintf_packaged.c.obj): in function `linker_is_in_rodata':
C:/Users/ofirs/bsp/zephyr/include/zephyr/linker/utils.h:54: undefined reference to `lnkr_pinned_rodata_start'
c:/users/ofirs/bsp/zephyr-sdk-0.16.8/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd.exe: C:/Users/ofirs/bsp/zephyr/include/zephyr/linker/utils.h:54: undefined reference to `lnkr_pinned_rodata_end'
collect2.exe: error: ld returned 1 exit status
ninja: build stopped: subcommand failed

The error seems to stem from missing linker symbols lnkr_pinned_rodata_start and lnkr_pinned_rodata_end.

For context, I'm using Zephyr version 4.0.99 (commit hash: 305ceba9204d9a7ee4bae0a6103ef4cbd9a1c54e).

Could you share how you resolved this issue on your end?

Thanks!

[DerekSnell]

Hi @ofirshe ,
Thanks for making me aware. My simple example did not have that issue. But I was able to replicate the build issue. I updated the example to include the pinned_rodata section, and I tested this on the mimxrt1060_evk board.

Best regards