ppc64le vmlinuz is huge when building with BTF

[Naveen N Rao]

Dominique Martinet wrote:
> Naveen N Rao wrote on Fri, Jun 16, 2023 at 04:28:53PM +0530:
>> > We're not stripping anything in vmlinuz for other archs -- the linker
>> > script already should be including only the bare minimum to decompress
>> > itself (+compressed useful bits), so I guess it's a Kbuild issue for the
>> > arch.
>> 
>> For a related discussion, see:
>> http://lore.kernel.org/CAK18DXZKs2PNmLndeGYqkPxmrrBR=6ca3bhyYCj=GhyA7dHfAQ@mail.gmail.com
> 
> Thanks, I didn't know that ppc64le boots straight into vmlinux, as 'make
> install' somehow installs something called 'vmlinuz-lts' (-lts coming
> out of localversion afaiu, but vmlinuz would come from the build
> scripts) ; this is somewhat confusing as vmlinuz on other archs is a
> compressed/pre-processed binary so I'd expect it to at least be
> stripped...

As far as I can tell, kernel's install script doesn't give out that 
name, so 'vmlinuz' is likely coming from the distro's 
/[s]bin/installkernel script. It probably needs an override to retain 
'vmlinux'. 

> 
>> > We can add a strip but I unfortunately have no way of testing ppc build,
>> > I'll ask around the build linux-kbuild and linuxppc-dev lists if that's
>> > expected; it shouldn't be that bad now that's figured out.
>> 
>> Stripping vmlinux would indeed be the way to go. As mentioned in the above
>> link, fedora also packages a strip'ed vmlinux for ppc64le:
>> https://src.fedoraproject.org/rpms/kernel/blob/4af17bffde7a1eca9ab164e5de0e391c277998a4/f/kernel.spec#_1797
> 
> It feels somewhat wrong to add a strip just for ppc64le after make
> install, but I guess we probably ought to do the same...
> I don't have any hardware to test booting the result though, I'll submit
> an update and ask for someone to test when it's done.
> (bit busy but that doesn't take long, will do that tomorrow morning
> before I forget)

Thanks! You're right that it's likely just powerpc that is different 
here. It sure would be nice if we can iron out issues with our zImage.


- Naveen