I used a Cortex-M4 chip similar to STM32, and now I want to place some frequently used functions in the fast Flash area, so I wrote the following code:

  .flash_zw0 : ALIGN(4)
  {
    *(.flash_ex)
  } >FAST_FLASH AT> FLASH

After compilation, I saw that the functions in the. map file were stored according to the specified section, but when the program ran to the functions in that section, it would enter a hardfault。

When I am not using AT>:

  .flash_zw0 : ALIGN(4)
  {
    *(.flash_ex)
  } >FAST_FLASH

There won’t be any issues with the program.
So I think the difference between VMA and LMA can cause program exceptions, but I don’t know the reason and solution. The addresses of these two regions in memory are far apart, and I must map them, otherwise the generated bin file will be too large to upgrade.