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

[Wei Chen <Wei.Chen@xxxxxxx>]

Hi Jan,

On 2022/7/6 13:44, Henry Wang wrote:
> Hi Jan,
>
> > -----Original Message-----
> > Subject: Re: [PATCH] EFI: strip xen.efi when putting it on the EFI partition
> >
> > On 09.06.2022 17:52, 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>
> > > ---
> > > GNU strip 2.38 appears to have issues when acting on a PE binary:
> > > - 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 retain its
> > >    size (or shrink),
> > > - linker version is changed in and timestamp zapped from the header.
> > > Older GNU strip (observed with 2.35.1) doesn't work at all ("Data
> > > Directory size (1c) exceeds space left in section (8)").
> > >
> > > Future GNU strip is going to honor --keep-file-symbols (and will also
> > > have the other issues fixed). Question is whether we should use that
> > > option (for the symbol table as a whole to make sense), or whether
> > > instead we should (by default) strip the symbol table as well.
> > Without any feedback / ack I guess I'll consider this of no interest
> > (despite having heard otherwise, triggering me to put together the
> > patch in the first place), and put on the pile of effectively
> > rejected patches.
> I did a test for this patch on my x86 machine and I think this patch is
> doing the correct thing, so:
>
> Tested-by: Henry Wang <Henry.Wang@xxxxxxx>
Because there was no Arm EFI environment in hand at the time, Henry only 
tested the x86 part.I have setup an Arm platform with UEFI v2.70 (EDK 
II, 0x00010000) today, and this patch works well when boot Xen as an EFI 
application from UEFI shell.
But the binaries sizes are the same with/without this patch. Is it expected?
I have enabled:
CONFIG_DEBUG=y
CONFIG_DEBUG_INFO=y
Is there anything I should be aware to test this patch?

-rwxrwxr-x 1 weic weic 1081504 Jul  7 18:43 xen
-rwxrwxr-x 1 weic weic 1081504 Jul  7 19:43 xen

Tested-by (Arm only): Wei Chen <Wei.Chen@xxxxxxx>

Thanks,
Wei Chen

> I also noticed that Julien is suggesting maybe we can have Anthony as
> the reviewer for this patch, so I also add him in the CC of this email.
>
> Kind regards,
> Henry
>
> > Jan