Re: [PATCH v2] x86: Avoid relocation information in final vmlinux

From: H. Peter Anvin
Date: Wed Nov 23 2022 - 12:48:43 EST


On November 23, 2022 7:54:29 AM PST, Borislav Petkov <bp@xxxxxxxxx> wrote:
>On Wed, Nov 23, 2022 at 04:43:20PM +0100, Petr Pavlu wrote:
>> The only post-link analysis tool in this case should be arch/x86/tools/relocs.
>> It produces a vmlinux.relocs file which is appended to vmlinux.bin. This is
>> all internal to the Linux build. I'm not aware of any external tooling, such
>> as kernel debuggers, that would require this relocation information in
>> vmlinux.
>
>It would be good to know why --emit-relocs was added in the first place
>- that might give us a hint. Lemme talk to Micha.
>
>> The size command used in your example includes only allocatable code, data and
>> bss sections. It does not show size of any relocation sections.
>
>This:
>
>361M vmlinux.before
>361M vmlinux.after
>
>is simple ls output.
>
>Maybe I need something else enabled in my .config which would show this
>significant difference *and* *explain* it.
>
>Thx.
>

The real question is: why does anyone care about the size of the vmlinux file specifically?