Force all data in a C file to be in .text (or other) section

Question

I am using gcc to compile some code for an ARM Cortex-M4F microcontroller. My application uses a large collection of data that I have conveniently written into a C file: large arrays of ints and floats, circular linked lists pointing to those various arrays, various structs, that sort of thing.

When I compile this it adds up to about 500K of data, plus a few hundred K for the actual application. gcc is putting all this data conveniently into the .data section; ld then tries to build the elf putting the .data section into RAM and .text (code) section into FLASH. The mcu I am using doesn't have 500K of RAM so it cannot build the ELF, but it does have 1M of FLASH. I tried changing my linker script so that both .data and .text are put into FLASH which "worked" but there are some other bit of code that expect its data to go into RAM, so ultimately execution failed; I can't make that sweeping change.

What I need is to tell gcc to put every single object in this C file into the .text section so it can go into FLASH with the rest of the non-mutable stuff, or at least some other section which I can then instruct my linker script what to do with so that it doesn't interfere with existing blobs that have no problem fitting in RAM. I don't know how to do that. Here is a very slimmed down example of what I have

/* data.c */
static char* option_array_0_0[] =
{
    "O=0.40",
    "K=FOO",
    "JAR=JAR",
};

static int width_array_0_0[] =
{
    0,
    1,
    1,
};

Window window_array_0[] =
{
    {
        option_array,
        width_array,
    },
};

/* main.c */
extern Window window_array_0[];
int main()
{
    /* Do stuff */
}

The stuff in data.c, window_array_0 and everything (or most everything, maybe the string arrays are going to .text?) it links to, is being put in .data which my linker script puts into RAM. I want it all in a different section which I can then put into FLASH. There are thousands of these types of arrays in there, plus hundreds of structs and dozens of other bits of information. Is this possible to change? As a test I replaced my "window_array_0" with a char[500000] of random data and that compiled without complaint so I assume it put it all into .text (as would be expected), I just don't know how to make it do so for arbitrary objects. Thanks for your help.

Answer 1

Most compilers/linkers, if you declare a variable as static const, it will place it in the text section instead of data. Obviously, these must be preinitialized and not modified at run-time, but that's the only way it makes sense to go in flash.