Using a custom memory section causes bin file is too big, how to solve it?

[jinshuaixu]

     In my project ,l find if l add the key words "attribute" to initialize variable, the bin file will change from 5k to 500M,which reason cause it ,who know how to solve it? 

Original Attachment has been moved to: App_demo_attribute.zip

[stanish · Accepted solution]

Hi,

This is caused by the fact your custom section (placed into RAM) is actually included in your project binary image.

The original linker script below needs to be modified.

MEMORY
{
...
/* SRAM_U */
 m_data_2 (RW) : ORIGIN = 0x20000000, LENGTH = 0x00007000
}
...
/* Custom Section Block that can be used to place data at absolute address. */
 /* Use __attribute__((section (".customSection"))) to place data here. */
 .customSectionBlock ORIGIN(m_data_2) :
 {
 KEEP(*(.customSection)) /* Keep section even if not referenced. */
 } > m_data_2
‍‍‍‍‍‍‍‍‍‍‍‍‍

The original linker script tells the linker to place the data section directly at 0x2000_0000 so it makes a huge gap in binary image of your app. Basically the gap begins at the code end address  (e.g.  0x0000_91e8) in flash and ends at the beginning of RAM (0x2000_0000)

S-record allows gaps so the size is relatively small but the binary raw image is a continuous memory block without any gaps - this causes it is so huge.

I assume this is not intended in your case since the project should run from Flash.

Therefore you should create a ROM image of your RAM section and let startup routine to perform ROM-to-RAM copy-down.

I'd suggest you to adjust the linker script file in order to create the ROM images for your custom RAM sections + avoid loading of uninitialized sections such as BSS, STACK, HEAP (see below the snippet of updated script file)

.

__DATA_END = __DATA_ROM + (__data_end__ - __data_start__);
  __CODE_ROM = __DATA_END; /* Symbol is used by code initialization. */

  .code : AT(__CODE_ROM) /* Load the section image at ROM address __CODE_ROM*/
  {
    . = ALIGN(4);
    __CODE_RAM = .;
    __code_start__ = .;      /* Create a global symbol at code start. */
    *(.code_ram)             /* Custom section for storing code in RAM */
    . = ALIGN(4);
    __code_end__ = .;        /* Define a global symbol at code end. */
  } > m_data

  __CODE_END = __CODE_ROM + (__code_end__ - __code_start__);
  __CUSTOM_ROM = __CODE_END;

  /* Custom Section Block that can be used to place data at absolute address. */
  /* Use __attribute__((section (".customSection"))) to place data here. */
  .customSectionBlock  : AT(__CUSTOM_ROM)  /* Load the section image at __CUSTOM_ROM*/
  {    
    __CUSTOM_RAM = .; /* Create Symbol used by startup to copydown*/
    __custom_start__ = .;  /* Define a global symbol at start. */    
    KEEP(*(.customSection))  /* Keep section even if not referenced. */
    __custom_end__ = .;    /* Define a global symbol at  end. */
  
  } > m_data_2
  
   /* Create Symbol used by startup to copydown*/
   __CUSTOM_END = __CUSTOM_ROM + (__custom_end__ -__custom_start__);



  /* Uninitialized data section. */
  .bss (NOLOAD) : /* Do not init this section */
  {
    /* This is used by the startup in order to initialize the .bss section. */
    . = ALIGN(4);
    __BSS_START = .;
    __bss_start__ = .;
    *(.bss)
    *(.bss*)
    *(COMMON)
    . = ALIGN(4);    __bss_end__ = .;
    __BSS_END = .;
  } > m_data_2

  .heap (NOLOAD): /* Do not init this section */
  {
    . = ALIGN(8);
    __end__ = .;
    PROVIDE(end = .);
    PROVIDE(_end = .);
    PROVIDE(__end = .);
    __HeapBase = .;
    . += HEAP_SIZE;
    __HeapLimit = .;
    __heap_limit = .;
  } > m_data_2

  .stack (NOLOAD): /* Do not init this section */
  {
    . = ALIGN(8);
    . += STACK_SIZE;
  } > m_data_2‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

The final step is to adjust the startup routine to initialize the custom RAM section.

Go to file "startup.c" located  "/App_demo/SDK/platform/devices/startup.c"

You should add the custom section symbols + custom initialization sequence:

void init_data_bss(void)
{
...
    uint8_t * custom_ram;   /*added for custom section init*/

...

    const uint8_t * custom_rom, * custom_rom_end; /*added for custom section init*/

...

    extern uint32_t __CUSTOM_RAM[];
    extern uint32_t __CUSTOM_ROM[];
    extern uint32_t __CUSTOM_END[];

...

/* CUSTOM RAM */
    custom_ram        = (uint8_t *)__CUSTOM_RAM;
    custom_rom        = (uint8_t *)__CUSTOM_ROM;
    custom_rom_end    = (uint8_t *)__CUSTOM_END;

....

/* Copy custom data from ROM to RAM */
    while (custom_rom_end != custom_rom)
    {
        *custom_ram = *custom_rom;
        custom_ram++;
        custom_rom++;
    }
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Attached is the modified project for you reference.

Hope it helps.

Stan

[danielmartynek]

Hi,

I cannot reproduce this issue.

Could you attach the project?

Regards,

Daniel

[jinshuaixu]

Hi Daniel

      l have upload the project,thank you for you helping.