armstm32ldlinker-scripts

STM32 linker script for only startup script from FLASH, everything else from RAM


I had an f7 with 1 MB internal flash memory. Thanks to international chip shortage I have to tackle a new challenge:

I now have an f7 with only 64kB internal flash and 16MB external qspi flash memory.

I need the bootloader to update the application in the external qspi flash memory. The bootloader does NOT fit into the internal flash. But I cannot write to the qspi memory while in memory map mode. So I init the external qspi flash memory, copy all of it into the RAM (I do have enough RAM) and run the bootloader from there. Or so i thought.

This is my linker script thought to only let the startup script run from external flash. But linker error relocation truncated to fit: R_ARM_PREL31 against `.text' shows up.

MEMORY
{
  FLASH (xr)      : ORIGIN = 0x90F00000, LENGTH = 1M
  RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 316K
}

/* Define output sections */
SECTIONS
{
  /* The startup code goes first into FLASH */
  .isr_vector :
  {
    . = ALIGN(4);
    KEEP(*(.isr_vector)) /* Startup code */
    . = ALIGN(4);
  } >FLASH
  
  /* The program code and other data goes into FLASH */
  .text.Reset_Handler :
  {
    . = ALIGN(4);
    *(.text)
    *(.text*)
    . = ALIGN(4);
  } >FLASH
  
  .text :
  {
    . = ALIGN(4);
    *(.text)           /* .text sections (code) */
    *(.text*)          /* .text* sections (code) */
    *(.glue_7)         /* glue arm to thumb code */
    *(.glue_7t)        /* glue thumb to arm code */
    *(.eh_frame)
    KEEP (*(.init))
    KEEP (*(.fini))

    . = ALIGN(4);
    _etext = .;        /* define a global symbols at end of code */
  } >RAM AT> FLASH

  /* Constant data goes into FLASH */
  .rodata :
  {
    . = ALIGN(4);
    *(.rodata)         /* .rodata sections (constants, strings, etc.) */
    *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */ 
    . = ALIGN(4);
  } >RAM AT> FLASH

  .ARM.extab   : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
  .ARM : {
    __exidx_start = .;
    *(.ARM.exidx*)
    __exidx_end = .;
  } >RAM AT> FLASH

  .preinit_array     :
  {
    PROVIDE_HIDDEN (__preinit_array_start = .);
    KEEP (*(.preinit_array*))
    PROVIDE_HIDDEN (__preinit_array_end = .);
  } >FLASH
  .init_array :
  {
    PROVIDE_HIDDEN (__init_array_start = .);
    KEEP (*(SORT(.init_array.*)))
    KEEP (*(.init_array*))
    PROVIDE_HIDDEN (__init_array_end = .);
  } >FLASH
  .fini_array :
  {
    PROVIDE_HIDDEN (__fini_array_start = .);
    KEEP (*(SORT(.fini_array.*)))
    KEEP (*(.fini_array*))
    PROVIDE_HIDDEN (__fini_array_end = .);
  } >FLASH

  /* used by the startup to initialize data */
  _sidata = LOADADDR(.data);

  /* Initialized data sections goes into RAM, load LMA copy after code */
  .data : 
  {
    . = ALIGN(4);
    _sdata = .;        /* create a global symbol at data start */
    *(.data)           /* .data sections */
    *(.data*)          /* .data* sections */

    . = ALIGN(4);
    _edata = .;        /* define a global symbol at data end */
  } >RAM AT >FLASH

  
  /* Uninitialized data section */
  . = ALIGN(4);
  .bss :
  {
    /* This is used by the startup in order to initialize the .bss secion */
    _sbss = .;         /* define a global symbol at bss start */
    __bss_start__ = _sbss;
    *(.bss)
    *(.bss*)
    *(COMMON)

    . = ALIGN(4);
    _ebss = .;         /* define a global symbol at bss end */
    __bss_end__ = _ebss;
  } >RAM

  /* User_heap_stack section, used to check that there is enough RAM left */
  ._user_heap_stack :
  {
/*    . = ALIGN(4); */
    . = ALIGN(8);
    PROVIDE ( end = . );
    PROVIDE ( _end = . );
    . = . + _Min_Heap_Size;
    . = . + _Min_Stack_Size;
/*    . = ALIGN(4); */
    . = ALIGN(8);
  } >RAM

  

  /* Remove information from the standard libraries */
  /DISCARD/ :
  {
    libc.a ( * )
    libm.a ( * )
    libgcc.a ( * )
  }

  .ARM.attributes 0 : { *(.ARM.attributes) }
}

Now I would like to get guidance on how to get over this PREL31 limitation or to tell me what I am doing wrong.


Solution

  • There is easier way to do this, you only need to change linker script, no need to change startup code

    /*
    ******************************************************************************
    **
    ** @file        : LinkerScript.ld
    **
    ** @author      : Auto-generated by STM32CubeIDE
    **
    **  Abstract    : Linker script for NUCLEO-F413ZH Board embedding STM32F413ZHTx Device from stm32f4 series
    **                      1536Kbytes FLASH
    **                      320Kbytes RAM
    **
    **                Set heap size, stack size and stack location according
    **                to application requirements.
    **
    **                Set memory bank area and size if external memory is used
    **
    **  Target      : STMicroelectronics STM32
    **
    **  Distribution: The file is distributed as is, without any warranty
    **                of any kind.
    **
    ******************************************************************************
    ** @attention
    **
    ** Copyright (c) 2022 STMicroelectronics.
    ** All rights reserved.
    **
    ** This software is licensed under terms that can be found in the LICENSE file
    ** in the root directory of this software component.
    ** If no LICENSE file comes with this software, it is provided AS-IS.
    **
    ******************************************************************************
    */
    
    /* Entry Point */
    ENTRY(Reset_Handler)
    
    /* Highest address of the user mode stack */
    _estack = ORIGIN(RAM) + LENGTH(RAM); /* end of "RAM" Ram type memory */
    
    _Min_Heap_Size = 0x200 ; /* required amount of heap */
    _Min_Stack_Size = 0x400 ; /* required amount of stack */
    
    /* Memories definition */
    MEMORY
    {
      RAM    (xrw)    : ORIGIN = 0x20000000,   LENGTH = 320K
      FLASH    (rx)    : ORIGIN = 0x8000000,   LENGTH = 1536K
    }
    
    /* Sections */
    SECTIONS
    {
      /* The startup code into "FLASH" Rom type memory */
      .isr_vector :
      {
        . = ALIGN(4);
        KEEP(*(.isr_vector)) /* Startup code */
        . = ALIGN(4);
      } >RAM AT> FLASH
      
        /* The program code and other data goes into FLASH */
      .text.Reset_Handler :
      {
        . = ALIGN(4);
        *(.text.Reset_Handler)
        . = ALIGN(4);
      } >FLASH
    
      /* The program code and other data into "FLASH" Rom type memory */
      .text :
      {
        . = ALIGN(4);
    
        KEEP (*(.init))
        KEEP (*(.fini))
    
        . = ALIGN(4);
        _etext = .;        /* define a global symbols at end of code */
      } >FLASH
    
      /* Constant data into "FLASH" Rom type memory */
      .rodata :
      {
        . = ALIGN(4);
    
        . = ALIGN(4);
      } >FLASH
    
      .ARM.extab   : {
        . = ALIGN(4);
        *(.ARM.extab* .gnu.linkonce.armextab.*)
        . = ALIGN(4);
      } >FLASH
    
      .ARM : {
        . = ALIGN(4);
        __exidx_start = .;
        *(.ARM.exidx*)
        __exidx_end = .;
        . = ALIGN(4);
      } >FLASH
    
      .preinit_array     :
      {
        . = ALIGN(4);
        PROVIDE_HIDDEN (__preinit_array_start = .);
        KEEP (*(.preinit_array*))
        PROVIDE_HIDDEN (__preinit_array_end = .);
        . = ALIGN(4);
      } >FLASH
    
      .init_array :
      {
        . = ALIGN(4);
        PROVIDE_HIDDEN (__init_array_start = .);
        KEEP (*(SORT(.init_array.*)))
        KEEP (*(.init_array*))
        PROVIDE_HIDDEN (__init_array_end = .);
        . = ALIGN(4);
      } >FLASH
    
      .fini_array :
      {
        . = ALIGN(4);
        PROVIDE_HIDDEN (__fini_array_start = .);
        KEEP (*(SORT(.fini_array.*)))
        KEEP (*(.fini_array*))
        PROVIDE_HIDDEN (__fini_array_end = .);
        . = ALIGN(4);
      } >FLASH
    
      /* Used by the startup to initialize data */
      _sidata = LOADADDR(.data);
    
      /* Initialized data sections into "RAM" Ram type memory */
      .data :
      {
        . = ALIGN(4);
        _sdata = .;        /* create a global symbol at data start */
        *(.data)           /* .data sections */
        *(.data*)          /* .data* sections */
        *(.RamFunc)        /* .RamFunc sections */
        *(.RamFunc*)       /* .RamFunc* sections */
        
        *(.text)           /* .text sections (code) */
        *(.text*)          /* .text* sections (code) */
        *(.glue_7)         /* glue arm to thumb code */
        *(.glue_7t)        /* glue thumb to arm code */
        *(.eh_frame)
        
        *(.rodata)         /* .rodata sections (constants, strings, etc.) */
        *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
    
        . = ALIGN(4);
        _edata = .;        /* define a global symbol at data end */
    
      } >RAM AT> FLASH
    
      /* Uninitialized data section into "RAM" Ram type memory */
      . = ALIGN(4);
      .bss :
      {
        /* This is used by the startup in order to initialize the .bss section */
        _sbss = .;         /* define a global symbol at bss start */
        __bss_start__ = _sbss;
        *(.bss)
        *(.bss*)
        *(COMMON)
    
        . = ALIGN(4);
        _ebss = .;         /* define a global symbol at bss end */
        __bss_end__ = _ebss;
      } >RAM
    
      /* User_heap_stack section, used to check that there is enough "RAM" Ram  type memory left */
      ._user_heap_stack :
      {
        . = ALIGN(8);
        PROVIDE ( end = . );
        PROVIDE ( _end = . );
        . = . + _Min_Heap_Size;
        . = . + _Min_Stack_Size;
        . = ALIGN(8);
      } >RAM
    
      /* Remove information from the compiler libraries */
      /DISCARD/ :
      {
        libc.a ( * )
        libm.a ( * )
        libgcc.a ( * )
      }
    
      .ARM.attributes 0 : { *(.ARM.attributes) }
    }