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LINKER script GCC how to avoid veneer call

I work on the project where I copy some functions to the RAM from FLASH and call them. Everything is OK except one small problem I have - if I call function directly the compiler adds the veneer call instead (which calls the funtion in the RAM correctly).

IF I call it via the pointer all is OK. The debugger shows that resolved address of the function is correct.

#define RAMFCALL(func, ...)   {unsigned (* volatile fptr)() =  (unsigned (* volatile)())func; fptr(__VA_ARGS__);}

RAMFCALL(FLASH_EraseSector, 0, 0);
FLASH_EraseSector(0,0);

and the corresponding calls:

 311        RAMFCALL(FLASH_EraseSector, 0, 0);
0801738e:   ldr     r3, [pc, #88]   ; (0x80173e8 <flashSTMInit+140>)
08017390:   str     r3, [sp, #12]
08017392:   ldr     r3, [sp, #12]
08017394:   movs    r1, #0
08017396:   mov     r0, r1
08017398:   blx     r3
 312        FLASH_EraseSector(0,0);
0801739a:   movs    r1, #0
0801739c:   mov     r0, r1
0801739e:   bl      0x801e9f0 <__FLASH_EraseSector_veneer>

Debugger shows the correct addresses.

enter image description here

and the corresponding part of the linker script 

  OVERLAY : NOCROSSREFS
  {
      .RAM_functions 
      {
        . = ALIGN(512);
        RAM_functions_load = LOADADDR(.RAM_functions);
        PROVIDE(RAM_VectorTable_start = .);
        KEEP(*(.RAM_VectorTable))
        KEEP(*(.RAM_VectorTable*))
        PROVIDE(RAM_VectorTable_end = .);

        . = ALIGN(4);
        RAM_functions_start = .;
        KEEP(*(.RAM_functions))
        KEEP(*(.RAM_functions*))
        RAM_functions_end = .;

        . = ALIGN(4);
        RAM_functionsDATA_start = .;
        KEEP(*(.RAM_functionsDATA))
        KEEP(*(.RAM_functionsDATA*))
        RAM_functionsDATA_end = .;   
        . = ALIGN(4);
        RAM_functionsBUFFER_start = .;
      } 

      /* used by the startup to initialize 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

And again the question: how to remove the veneer call

Solution

  • I will answer myself as I have found the reason :)

    The bl instruction is += 32MB relative to PC. I was calling the function in the RAM from FLASH and the actual distance was much longer than 32MB. So the linker had to place the veneer function call.