[U-Boot] [PATCH v1 6/7] MIPS: u-boot.lds: add relocation specific sections

[Gabor Juhos <juhosg@openwrt.org>]

2013.02.09. 21:33 keltez?ssel, daniel.schwierzeck at gmail.com ?rta:
> From: Gabor Juhos <juhosg@openwrt.org>
> 
> This section contain the table needed for dynamic
> relocation. Also provide symbols for the relocation
> code to access the table.
> 
> Discard all sections which are not needed in the final
> ELF binary and U-Boot image. Section .dynsym cannot be
> discarded or GNU ld crashes otherwise. This section
> will be stripped by GNU objcpy in a later patch.
> 
> Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
> Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
> ---
>  arch/mips/cpu/u-boot.lds | 24 +++++++++++++++++++++++-
>  1 file changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/mips/cpu/u-boot.lds b/arch/mips/cpu/u-boot.lds
> index 4cd983a..cea9533 100644
> --- a/arch/mips/cpu/u-boot.lds
> +++ b/arch/mips/cpu/u-boot.lds
> @@ -70,7 +70,17 @@ SECTIONS
>  	. = ALIGN(4);
>  	__image_copy_end = .;
>  
> -	.bss : {
> +	.rel.dyn : {
> +		__rel_dyn_start = .;
> +		*(.rel.dyn)
> +		__rel_dyn_end = .;
> +	}
> +
> +	.dynsym : {
> +		*(.dynsym)
> +	}

This is not enough to avoid the binutils issue I have mentioned in the original
patch. The issue is present after applying this series.

The following example comes from the qemu_mips target compiled with the ELDK 5.3
toolchain:

> $ mips-linux-objdump --disassemble u-boot | grep bfc005[67]
> bfc00560:       00000000        nop
> bfc00564:       bfc31f74        cache   0x3,8052(s8)    <--- __rel_dyn_end

The offset of __rel_dyn_end:
0x0bfc31f74 - 0xbfc00000 = 0x31f74 = 204660

> bfc00568:       bfc30804        cache   0x3,2052(s8)
> bfc0056c:       bfc30804        cache   0x3,2052(s8)
> bfc00570:       bfc2fa70        cache   0x2,-1424(s8)
> bfc00574:       000001df        0x1df
> bfc00578 <in_ram>:
> bfc00578:       8d0bfffc        lw      t3,-4(t0)
> bfc0057c:       8d0cfff8        lw      t4,-8(t0)

> $ ls -l u-boot.bin
> -rw-r--r-- 1 juhosg root 204284 Feb 11 11:29 u-boot.bin

204660 - 204284 = 376 bytes are missing from the final u-boot.bin.

-Gabor