How can I solve “Linker Section Placement Error” in IAR

Question

I am trying to run some basic Ethernet applications (via lwIP) on an ARM Cortex M3 which is on board a M2S150 Development kit and have run into an issue I don't understand:

Error[Lp011]: section placement failed unable to allocate space for sections/blocks with a total estimated minimum size of 0x8dc8 bytes (max align 0x8) in <[0x20008000-0x2000ffff]> (total uncommitted space 0x8000).

Upon further research some forums mentioned that the issue may be that your program does not fit in flash (which I doubt considering I am calling one function just to test things out). Other sources mentioning modifying the linker icf file, but I am not sure if this is the right way to go about it given that Libero generates the icf files when you create a IAR project and would have information on the dev board you are using.

This is the current code I am trying to run:

/* lwIP includes. */
#include "lwip/init.h"

int main(void)
{
  
  lwip_init();

  for(;;){}

  //Should never reach here.
  return 0;
}

Would anyone be able to provide some insight on why this is happening?

EDIT Added ESRAM ICF file:

/******************************************************************************/
/*  (c) Copyright 2015 Microsemi SoC Products Group. All rights reserved.     */
/*  SmartFusion2 scatter file for debugging code executing in internal eSRAM. */
/*                                                                            */
/*  SVN $Revision: 7419 $                                                     */
/*  SVN $Date: 2015-05-15 16:50:21 +0100 (Fri, 15 May 2015) $                 */
/******************************************************************************/
/* 
 * Some current (April 2015) dev kit memory map possibilities are
 * --Type-------Device-----------address start---address end----size---Dbus--RAM IC-------SF2--Comment---------------
 * --eNVM-------M2S010-----------0x60000000------0x6007FFFF-----256KB---------------------010------------------------
 * --eNVM-------M2S090-----------0x60000000------0x6007FFFF-----512KB---------------------090------------------------
 * --eSRAM------M2Sxxx-----------0x20000000------0x2000FFFF-----64KB----------------------xxx--All have same amount--
 * --eSRAM------M2Sxxx-----------0x20000000------0x20013FFF-----80KB----------------------xxx--If ECC/SECDED not used
 * --Fabric-----M2S010-----------0x30000000------0x6007FFFF-----400Kb---------------------010--note-K bits-----------
 * --Fabric-----M2S090-----------0x30000000------0x6007FFFF-----2074Kb--------------------090--note-K bits-----------
 * --LPDDR------STARTER-KIT------0xA0000000------0xA3FFFFFF-----64MB---16--MT46H32M16-----050------------------------
 * --LPDDR------484-STARTER-KIT--0xA0000000------0xA3FFFFFF-----64MB---16--MT46H32M16-----010------------------------
 * --LPDDR------SEC-EVAL-KIT-----0xA0000000------0xA3FFFFFF-----64MB---16--MT46H32M16LF---090--Security eval kit-----
 * --DDR3-------ADevKit----------0xA0000000------0xBFFFFFFF-----1GB----32--MT41K256M8DA---150------------------------
 * --Some older physical memory map possibilities are
 * --Type-------location---------address start---address end----size---Dbus---RAM IC------SF2--Comment--------------
 * --LPDDR------EVAL KIT---------0xA0000000------0xA3FFFFFF-----64MB-=-16--MT46H32M16LF---025--Eval Kit--------------
 * --DDR3-------DevKit-----------0xA0000000------0xAFFFFFFF-----512MB--16--MT41K256M8DA---050------------------------
 */
/*###ICF### Section handled by ICF editor, don't touch! ****/
/*-Editor annotation file-*/
/* IcfEditorFile="$TOOLKIT_DIR$\config\ide\IcfEditor\cortex_v1_0.xml" */
/*-Specials-*/
define symbol __ICFEDIT_intvec_start__ = 0x20000000;
/*-Memory Regions-*/
define symbol __ICFEDIT_region_ROM_start__ = 0x20000000;
define symbol __ICFEDIT_region_ROM_end__   = 0x20007FFF;
define symbol __ICFEDIT_region_RAM_start__ = 0x20008000;
define symbol __ICFEDIT_region_RAM_end__   = 0x2000FFFF;
/*-Sizes-*/
define symbol __ICFEDIT_size_cstack__ = 0x400;
define symbol __ICFEDIT_size_heap__   = 0x800;
/**** End of ICF editor section. ###ICF###*/

define memory mem with size = 4G;
define region ROM_region   = mem:[from __ICFEDIT_region_ROM_start__   to __ICFEDIT_region_ROM_end__];
define region RAM_region   = mem:[from __ICFEDIT_region_RAM_start__   to __ICFEDIT_region_RAM_end__];

define block CSTACK    with alignment = 8, size = __ICFEDIT_size_cstack__   { };
define block HEAP      with alignment = 8, size = __ICFEDIT_size_heap__     { };

initialize by copy { readwrite };
do not initialize  { section .noinit };

place at address mem:__ICFEDIT_intvec_start__ { readonly section .intvec };

place in ROM_region   { readonly };
place in RAM_region   { readwrite,
                        block CSTACK, block HEAP };

Answer 1

The error message tells you that you have instructed the linker to put 36296 bytes of data in a memory region of size 32768. By matching the address range in the error message with the region definitions in the .icf-file you can see that this corresponds to RAM_region.

According to the place-directive this region contains all readwrite data, the predefined block CSTACK and the predefined block HEAP. Since the stack and heap blocks are small, the main culprit is probably the size of the readwrite data. To find out how much read-write data each module needs you can use the linker map-file. The map-file contains a module summary that looks something like the example below. This section lists each object files contribution to the resulting binary (including the files in the system libraries). As an example, file1.o below contributes with 44 bytes of code and 5 bytes of data.

***************************************************************************
*** MODULE SUMMARY
***

    Module            ro code  ro data  rw data
    ------            -------  -------  -------
command line/config:
    -------------------------------------------
    Total:

/home/johanb/slask: [1]
    file1.o                44                 5
    file2.o                20
    file3.o                44                 1
    -------------------------------------------
    Total:                108                 6

dl7Sx_tln.a: [2]
    exit.o                  4
    low_level_init.o        4
    -------------------------------------------
    Total:                  8

m7Sx_tlv.a: [3]
    fpinit.o               40
    -------------------------------------------
    Total:                 40

rt7Sx_tl.a: [4]
    cexit.o                16
    cmain.o                48
    cstartup.o            148
    data_init.o            48
    vectortrap.o            4
    zero_init3.o           56
    -------------------------------------------
    Total:                320

sh7Sxs_l.a: [5]
    exit.o                 20
    unwind_debug.o                   1
    xreturnswi.o            4
    -------------------------------------------
    Total:                 24        1

    Linker created          8       16   32'768
-----------------------------------------------
    Grand Total:          508       17   32'774