Apply d799769188529abc6cbf035a10087a51f7832b6b to 5.17 and 5.15?

From: Nathan Chancellor <nathan@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Sasha Levin <sashal@kernel.org>,
	Michael Ellerman <mpe@ellerman.id.au>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
	Tom Rix <trix@redhat.com>, Paul Menzel <pmenzel@molgen.mpg.de>,
	stable@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	llvm@lists.linux.dev
Subject: Apply d799769188529abc6cbf035a10087a51f7832b6b to 5.17 and 5.15?
Date: Tue, 19 Apr 2022 14:27:19 -0700	[thread overview]
Message-ID: <Yl8pNxSGUgeHZ1FT@dev-arch.thelio-3990X> (raw)

Hi Greg, Sasha, and Michael,

Commit d79976918852 ("powerpc/64: Add UADDR64 relocation support") fixes
a boot failure with CONFIG_RELOCATABLE=y kernels linked with recent
versions of ld.lld [1]. Additionally, it resolves a separate boot
failure that Paul Menzel reported [2] with ld.lld 13.0.0. Is this a
reasonable backport for 5.17 and 5.15? It applies cleanly, resolves both
problems, and does not appear to cause any other issues in my testing
for both trees but I was curious what Michael's opinion was, as I am far
from a PowerPC expert.

This change does apply cleanly to 5.10 (I did not try earlier branches)
but there are other changes needed for ld.lld to link CONFIG_RELOCATABLE
kernels in that branch so to avoid any regressions, I think it is safe
to just focus on 5.15 and 5.17.

Paul, it would not hurt to confirm the results of my testing with your
setup, just to make sure I did not miss anything :)

[1]: https://github.com/ClangBuiltLinux/linux/issues/1581
[2]: https://lore.kernel.org/Yg2h2Q2vXFkkLGTh@dev-arch.archlinux-ax161/

Cheers,
Nathan