Subject: Re: [PATCH 2/2] powerpc/vmlinux.lds: Discard .interp section

From: Alan Modra <[email-masked]>
Date: Thu, 27 Feb 2020 16:57:50 +1030

On Thu, Feb 27, 2020 at 03:59:33PM +1100, Michael Ellerman wrote:
> The .interp section specifies which "interpreter", ie. dynamic loader,
> the kernel requests. But that doesn't make any sense, the kernel is
> not a regular binary that is run with an interpreter.
> 
> The content seems to be some default value, this file doesn't even
> exist on my system:
>   00000000  2f 75 73 72 2f 6c 69 62  2f 6c 64 2e 73 6f 2e 31  |/usr/lib/ld.so.1|
> 
> So the section serves no useful purpose and consumes a small amount of
> space.
> 
> Also Alan Modra says we "likely could discard" it, so do so.

Yes, but you ought to check with the mimimum required binutils.  It is
quite possible that an older linker will blow up.

If the minimum required binutils is at least binutils-2.26 then
passing --no-dynamic-linker to ld is a more elegant solution.

> 
> Signed-off-by: Michael Ellerman <[email-masked]>
> ---
>  arch/powerpc/kernel/vmlinux.lds.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
> index 31a0f201fb6f..619ffbaf72ad 100644
> --- a/arch/powerpc/kernel/vmlinux.lds.S
> +++ b/arch/powerpc/kernel/vmlinux.lds.S
> @@ -257,7 +257,6 @@ SECTIONS
>  	}
>  	.hash : AT(ADDR(.hash) - LOAD_OFFSET) { *(.hash) }
>  	.gnu.hash : AT(ADDR(.gnu.hash) - LOAD_OFFSET) { *(.gnu.hash) }
> -	.interp : AT(ADDR(.interp) - LOAD_OFFSET) { *(.interp) }
>  	.rela.dyn : AT(ADDR(.rela.dyn) - LOAD_OFFSET)
>  	{
>  		__rela_dyn_start = .;
> @@ -370,5 +369,6 @@ SECTIONS
>  		*(.gnu.version*)
>  		*(.gnu.attributes)
>  		*(.eh_frame)
> +		*(.interp)
>  	}
>  }
> -- 
> 2.21.1

-- 
Alan Modra
Australia Development Lab, IBM