Compile a function to a different memory location

Mbed OS
1

Using an stm32f746 disco, I’m trying to get a function to compile to a different memory location using Mbed.

so far, as a test, i have this mbed_app.json…

{
    "target_overrides": {
        "*": {
            "target.ld_script": "custom_stm32f746.ld"
        }
    }
}

then this custom_stm32f746.ld…

/* Linker script to configure memory regions. */

MEMORY
{
FLASH (rx) : ORIGIN = 0x08000000, LENGTH = 1024K
RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 320K
CUSTOM_SECTION (rx) : ORIGIN = 0x080C0000, LENGTH = 128K
}

/* Define entry point */
ENTRY(Reset_Handler)

/* Section Definitions */
SECTIONS
{
.text :
{
*(.text)
*(.text.*)
} > FLASH

.custom_section :
{
KEEP(*(.custom_section))
} > CUSTOM_SECTION

.data :
{
*(.data)
} > RAM AT > FLASH

.bss :
{
*(.bss)
} > RAM

/* Other sections */
}

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and this in my main.c…

__attribute__((section(".custom_section"))) void myFunction(void);

__attribute__((section(".custom_section"), used)) void myFunction() {

        printf("This function is at %0xH\n", (int) myFunction);

}

but the output is…

This function is at 8000259H

and using the cube programmer the memory at 80c0000 is unchanged

2

Can you post the .map file? Does it reference myFunction at all?