MEK-MIMX8QX eval board and NXP rev 2.5.0 SDK.
Developing app in C for the Cortex-M4.
ARM GCC embedded compiler v5.4 2016q3. (I would like to use a newer one but I believe this is the latest version the current SDK supports.)
Our application requires a few RAM variables declared with the gcc "noinit" attribute so they don't get cleared across a soft reboot of the Cortex-M4. On the first access of any of these noinit variables, the application crashes. I don't have a debugger currently so I'm not sure exactly what exception it's hitting.
In the attachment, I've modified the demo hello_world app to show what's going on. I'm building with the "build_release.bat" script.
In hello_world.c I added:
// Attempt #1 - This worked using NXP S32K Design Studio and gcc compiler ...
//int __attribute__ ((section("noinit"))) MyNoInitVariable;
// Attempt #2 - This is what I've seen in various articles on the web ...
int __attribute__ ((section(".noinit"))) MyNoInitVariable;
PRINTF("Before read ...\r\n");
PRINTF("Before write ...\r\n");
MyNoInitVariable = 0xAAAAAAAA;
PRINTF("After write ...\r\n");
When this runs, only the "Before read ..." printf works, then the application hangs. As you can see, I tried naming the noinit section "noinit" and also ".noinit" and both versions fail.
NOTE: This exact same application works using the "noinit" section name when I compile and run on an NXP S32K146 eval board.