Re: [PATCH RFC] EFI: strip xen.efi when putting it on the EFI partition

[Jan Beulich <jbeulich@xxxxxxxx>]

On 25.04.2022 12:46, Jan Beulich wrote:
> With debug info retained, xen.efi can be quite large. Unlike for xen.gz
> there's no intermediate step (mkelf32 there) involved which would strip
> debug info kind of as a side effect. While the installing of xen.efi on
> the EFI partition is an optional step (intended to be a courtesy to the
> developer), adjust it also for the purpose of documenting what distros
> would be expected to do during boot loader configuration (which is what
> would normally put xen.efi into the EFI partition).
> 
> Model the control over stripping after Linux'es module installation,
> except that the stripped executable is constructed in the build area
> instead of in the destination location. This is to conserve on space
> used there - EFI partitions tend to be only a few hundred Mb in size.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
> RFC: GNU strip 2.38 appears to have issues when acting on a PE binary:
>      - the new file positions of the sections do not respect the file
>        alignment specified by the header (a resulting looks to work on
>        one EFI implementation where I did actually try it, but I don't
>        think we can rely on that),
>      - file name symbols are also stripped; while there is a separate
>        --keep-file-symbols option (which I would have thought to be on
>        by default anyway), its use makes no difference.

Update to these items: The first one turned out to be an issue with a
not-yet-upstream patch that I've been carrying for a long time. I've
fixed that up, and will submit that patch (perhaps together with
further ones) in due course. Apart from that the list of remarks now
is

- file name symbols are also stripped; while there is a separate
  --keep-file-symbols option (which I would have thought to be on by
  default anyway), its use so far makes no difference,
- the string table grows in size, when one would expect it to shrink,
- linker version is changed in and timestamp zapped from the header.

Locally I have draft patches for all of these issues, but this means
stripping won't work overly well until at least 2.39.

Jan