Краткие заметки embed-программиста: дублирование секции в памяти микроконтроллера

MEMORY
{
    FLASH (rx) : ORIGIN = 0x08000000, LENGTH = 1024K - 256K /* 256 КБ для user_cfg */
   USER_CFG_PAGE_1 (rx) : ORIGIN = 0x080C0000, LENGTH = 128K - 4     /* 4 Байта CRC32 */
    USER_CFG_PAGE_2 (rx) : ORIGIN = 0x080E0000, LENGTH = 128K - 4     /* 4 Байта CRC32 */
    CCM (xrw) : ORIGIN = 0x10000000, LENGTH = 64K
    RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 128K
}

/* Записывается размер с учетом поля под CRC32.
   А компоновщик работает без него. Чтобы если структура не залезет - предупредить. */
user_cfg_data_flash_page_1_size = LENGTH(user_cfg_PAGE_1) + 4;
user_cfg_data_flash_page_2_size = LENGTH(user_cfg_PAGE_2) + 4;
user_cfg_data_flash_page_size = user_cfg_data_flash_page_1_size;

/*
 * The '__stack' definition is required by crt0, do not remove it.
 */
__stack = ORIGIN(RAM) + LENGTH(RAM);

_estack = __stack;     /* STM specific definition */

/*
 * Default stack sizes.
 * These are used by the startup in order to allocate stacks
 * for the different modes.
 */

__Main_Stack_Size = 1024 ;

PROVIDE ( _Main_Stack_Size = __Main_Stack_Size ) ;

__Main_Stack_Limit = __stack  - __Main_Stack_Size ;

/*"PROVIDE" allows to easily override these values from an object file or the command line. */
PROVIDE ( _Main_Stack_Limit = __Main_Stack_Limit ) ;

/*
 * There will be a link error if there is not this amount of
 * RAM free at the end.
 */
_Minimum_Stack_Size = 512 ;

/*
 * Default heap definitions.
 * The heap start immediately after the last statically allocated
 * .sbss/.noinit section, and extends up to the main stack limit.
 */
PROVIDE ( _Heap_Begin = _end_noinit ) ;
PROVIDE ( _Heap_Limit = __stack - __Main_Stack_Size ) ;

SECTIONS
{
    .isr_vector :
    {
        KEEP(*(.isr_vector))         /* Interrupt vectors */
        KEEP(*(.cfmconfig))            /* Freescale configuration words */
        *(.after_vectors .after_vectors.*)    /* Startup code and ISR */
        . = ALIGN(4);
    } >FLASH

    .inits :
    {
        . = ALIGN(4);

        /*
         * These are the old initialisation sections, intended to contain
         * naked code, with the prologue/epilogue added by crti.o/crtn.o
         * when linking with startup files. The standalone startup code
         * currently does not run these, better use the init arrays below.
         */
        KEEP(*(.init))
        KEEP(*(.fini))

        . = ALIGN(4);

        /*
         * The preinit code, i.e. an array of pointers to initialisation
         * functions to be performed before constructors.
         */
        PROVIDE_HIDDEN (__preinit_array_start = .);

        /*
         * Used to run the SystemInit() before anything else.
         */
        KEEP(*(.preinit_array_sysinit .preinit_array_sysinit.*))

        /*
         * Used for other platform inits.
         */
        KEEP(*(.preinit_array_platform .preinit_array_platform.*))

        /*
         * The application inits. If you need to enforce some order in
         * execution, create new sections, as before.
         */
        KEEP(*(.preinit_array .preinit_array.*))

        PROVIDE_HIDDEN (__preinit_array_end = .);

        . = ALIGN(4);

        /*
         * The init code, i.e. an array of pointers to static constructors.
         */
        PROVIDE_HIDDEN (__init_array_start = .);
        KEEP(*(SORT(.init_array.*)))
        KEEP(*(.init_array))
        PROVIDE_HIDDEN (__init_array_end = .);

        . = ALIGN(4);

        /*
         * The fini code, i.e. an array of pointers to static destructors.
         */
        PROVIDE_HIDDEN (__fini_array_start = .);
        KEEP(*(SORT(.fini_array.*)))
        KEEP(*(.fini_array))
        PROVIDE_HIDDEN (__fini_array_end = .);
        . = ALIGN(4);

    } >FLASH

    /*
     * For some STRx devices, the beginning of the startup code
     * is stored in the .flashtext section, which goes to FLASH.
     */
    .flashtext :
    {
        . = ALIGN(4);
        *(.flashtext .flashtext.*)    /* Startup code */
        . = ALIGN(4);
    } >FLASH


    /*
     * The program code is stored in the .text section,
     * which goes to FLASH.
     */
    .text :
    {
        . = ALIGN(4);

        *(.text .text.*)            /* all remaining code */

        *(.rodata .rodata.*)         /* read-only data (constants) */

        *(vtable)                    /* C++ virtual tables */

        KEEP(*(.eh_frame*))

        /*
         * Stub sections generated by the linker, to glue together
         * ARM and Thumb code. .glue_7 is used for ARM code calling
         * Thumb code, and .glue_7t is used for Thumb code calling
         * ARM code. Apparently always generated by the linker, for some
         * architectures, so better leave them here.
         */
        *(.glue_7)
        *(.glue_7t)
    } >FLASH

    .user_cfg_data_flash_default_page :
    {
        . = ALIGN(4);
        user_cfg_data_flash_default_page_start = .;
        KEEP(*(.user_cfg_data_flash_default_page .user_cfg_data_flash_default_page.*))
        . = ALIGN(4);
        user_cfg_data_flash_default_page_stop = .;
    } >FLASH

    /* ARM magic sections */
    .ARM.extab :
       {
       *(.ARM.extab* .gnu.linkonce.armextab.*)
       } > FLASH

       __exidx_start = .;
       .ARM.exidx :
       {
       *(.ARM.exidx* .gnu.linkonce.armexidx.*)
       } > FLASH
       __exidx_end = .;

    . = ALIGN(4);
    _etext = .;
    __etext = .;

    /*
     * This address is used by the startup code to
     * initialise the .data section.
     */
    _sidata = _etext;

    /* MEMORY_ARRAY */
    /*
    .ROarraySection :
    {
         *(.ROarraySection .ROarraySection.*)
    } >MEMORY_ARRAY
    */

    /*
     * The initialised data section.
     * The program executes knowing that the data is in the RAM
     * but the loader puts the initial values in the FLASH (inidata).
     * It is one task of the startup to copy the initial values from
     * FLASH to RAM.
     */
    .data  : AT ( _sidata )
    {
        . = ALIGN(4);

        /* This is used by the startup code to initialise the .data section */
        _sdata = . ;            /* STM specific definition */
        __data_start__ = . ;
        *(.data_begin .data_begin.*)

        *(.data .data.*)

        *(.data_end .data_end.*)

        *(.ramfunc*)
        . = ALIGN(4);

        /* This is used by the startup code to initialise the .data section */
        _edata = . ;            /* STM specific definition */
        __data_end__ = . ;

    } >RAM


    /*
     * The uninitialised data section. NOLOAD is used to avoid
     * the "section `.bss' type changed to PROGBITS" warning
     */
    .bss (NOLOAD) :
    {
        . = ALIGN(4);
        __bss_start__ = .;         /* standard newlib definition */
        _sbss = .;              /* STM specific definition */
        *(.bss_begin .bss_begin.*)

        *(.bss .bss.*)
        *(COMMON)

        *(.bss_end .bss_end.*)
        . = ALIGN(4);
        __bss_end__ = .;        /* standard newlib definition */
        _ebss = . ;             /* STM specific definition */
    } >RAM

    .user_cfg_data_ram_page :
    {
        . = ALIGN(4);
        user_cfg_data_ram_page_start = .;
        KEEP(*(.user_cfg_data_ram_page .user_cfg_data_ram_page.*))
        . = ALIGN(4);
        user_cfg_data_ram_page_stop = .;
    } > CCM

    user_cfg_data_ram_page_size = user_cfg_data_ram_page_stop - user_cfg_data_ram_page_start;

    .user_cfg_data_page_1 :
    {
        . = ALIGN(4);
        user_cfg_data_flash_page_1_start = .;
         KEEP(*(.user_cfg_data_flash_page_1 .user_cfg_data_flash_page_1.*))
        . = ALIGN(4);
        user_cfg_data_flash_page_1_stop = .;
    } > user_cfg_PAGE_1

    .user_cfg_data_page_2 :
    {
        . = ALIGN(4);
        user_cfg_data_flash_page_2_start = .;
         KEEP(*(.user_cfg_data_flash_page_2 .user_cfg_data_flash_page_2.*))
        . = ALIGN(4);
        user_cfg_data_flash_page_2_stop = .;
    } > user_cfg_PAGE_2

    .noinit (NOLOAD) :
    {
        . = ALIGN(4);
        _noinit = .;

        *(.noinit .noinit.*)

         . = ALIGN(4) ;
        _end_noinit = .;
    } > RAM

    /* Mandatory to be word aligned, _sbrk assumes this */
    PROVIDE ( end = _end_noinit ); /* was _ebss */
    PROVIDE ( _end = _end_noinit );
    PROVIDE ( __end = _end_noinit );
    PROVIDE ( __end__ = _end_noinit );

    /*
     * Used for validation only, do not allocate anything here!
     *
     * This is just to check that there is enough RAM left for the Main
     * stack. It should generate an error if it's full.
     */
    ._check_stack :
    {
        . = ALIGN(4);
        . = . + _Minimum_Stack_Size ;
        . = ALIGN(4);
    } >RAM


    /* After that there are only debugging sections. */

    /* This can remove the debugging information from the standard libraries */
    /*
    DISCARD :
    {
     libc.a ( * )
     libm.a ( * )
     libgcc.a ( * )
     }
     */

    /* Stabs debugging sections.  */
    .stab          0 : { *(.stab) }
    .stabstr       0 : { *(.stabstr) }
    .stab.excl     0 : { *(.stab.excl) }
    .stab.exclstr  0 : { *(.stab.exclstr) }
    .stab.index    0 : { *(.stab.index) }
    .stab.indexstr 0 : { *(.stab.indexstr) }
    .comment       0 : { *(.comment) }
    /*
     * DWARF debug sections.
     * Symbols in the DWARF debugging sections are relative to the beginning
     * of the section so we begin them at 0.
     */
    /* DWARF 1 */
    .debug          0 : { *(.debug) }
    .line           0 : { *(.line) }
    /* GNU DWARF 1 extensions */
    .debug_srcinfo  0 : { *(.debug_srcinfo) }
    .debug_sfnames  0 : { *(.debug_sfnames) }
    /* DWARF 1.1 and DWARF 2 */
    .debug_aranges  0 : { *(.debug_aranges) }
    .debug_pubnames 0 : { *(.debug_pubnames) }
    /* DWARF 2 */
    .debug_info     0 : { *(.debug_info .gnu.linkonce.wi.*) }
    .debug_abbrev   0 : { *(.debug_abbrev) }
    .debug_line     0 : { *(.debug_line) }
    .debug_frame    0 : { *(.debug_frame) }
    .debug_str      0 : { *(.debug_str) }
    .debug_loc      0 : { *(.debug_loc) }
    .debug_macinfo  0 : { *(.debug_macinfo) }
    /* SGI/MIPS DWARF 2 extensions */
    .debug_weaknames 0 : { *(.debug_weaknames) }
    .debug_funcnames 0 : { *(.debug_funcnames) }
    .debug_typenames 0 : { *(.debug_typenames) }
    .debug_varnames  0 : { *(.debug_varnames) }
}