Puzzle about .rel.dyn section generated for mips elf target executables

["Amker.Cheng" <amker dot cheng at gmail dot com>]

Hi :
    Giving a simple example, which consists of test.c and test.xn

--------------------------------------------------------test.c start
int x11;
int *xxp = &x11;

int main()
{
  return *xxp;
}
--------------------------------------------------------test.c end

--------------------------------------------------------test.xn start
OUTPUT_FORMAT("elf32-tradlittlemips", "elf32-tradbigmips",
"elf32-tradlittlemips")
OUTPUT_ARCH(mips)
ENTRY(main)

SECTIONS
{
	.text 0xb4060000:
	{
	 *(.text);
	 *(.rodata);
	}
    .data           :
    {
      _fdata = . ;
      *(.data .data.* .gnu.linkonce.d.*)
      KEEP (*(.gnu.linkonce.d.*personality*))
      SORT(CONSTRUCTORS)
    }
	
	_gp = ALIGN(16) + 0x7ff0;
    .got            : { *(.got.plt) *(.got) }
    .sdata          :
    {
      *(.sdata .sdata.* .gnu.linkonce.s.*)
    }

    .sbss           :
    {
	  *(.dynsbss)
      *(.sbss .sbss.* .gnu.linkonce.sb.*)
      *(.scommon)
    }

    .bss            :
    {
     *(.dynbss)
     *(.bss .bss.* .gnu.linkonce.b.*)
     *(COMMON)
    }
}
--------------------------------------------------------test.xn end

build by command lines like:

mipsel-sde-elf-gcc -march=mips1 -O2 -c -EL -G0 test.c -o test.o
mipsel-sde-elf-ld -EL -G0 test.o -T test.xn -o a.out

checking sections in a.out by

mipsel-sde-elf-readelf -S a.out

outputs captured as following:

Section Headers:
  [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al
  [ 0]                   NULL            00000000 000000 000000 00      0   0  0
  [ 1] .text             PROGBITS        b4060000 010000 000018 00  AX  0   0  4
  [ 2] .rel.dyn          REL             b4060018 010018 000010 08   A  0   0  4
        ^------------------------- Please attention

  [ 3] .data             PROGBITS        b4060028 010028 000004 00  WA  0   0  4
  [ 4] .bss              NOBITS          b406002c 01002c 000004 00  WA  0   0  4
  [ 5] .reginfo          MIPS_REGINFO    00000000 01002c 000018 18      0   0  4
  [ 6] .pdr              PROGBITS        00000000 010044 000020 00      0   0  4
  [ 7] .comment          PROGBITS        00000000 010064 000012 00      0   0  1
  [ 8] .gnu.attributes   LOOS+ffffff5    00000000 010076 000010 00      0   0  1
  [ 9] .shstrtab         STRTAB          00000000 010086 00005c 00      0   0  1
  [10] .symtab           SYMTAB          00000000 0102c4 0000f0 10     11  10  4
  [11] .strtab           STRTAB          00000000 0103b4 000020 00      0   0  1

Though relocation in .rel.dyn are all REL_MIPS_NONE, I'm wondering
 why .rel.dyn section is generated for this simple elf target executable?
Does it necessary?

BTW, i am testing on GCC4.4.1 and BINUTILS-2.19.51 configure as mipsel-sde-elf
both including my own modification, which would never affect this testcase.

any explanation? Thanks in advance.

-- 
Best Regards.