linux-kernel - Re: [PATCH v2] efistub: Only link libstub to final vmlinux

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <aRsH7RTpAah4g5Xr@willie-the-truck>
Date: Mon, 17 Nov 2025 11:33:01 +0000
From: Will Deacon <will@...nel.org>
To: Huacai Chen <chenhuacai@...nel.org>
Cc: Josh Poimboeuf <jpoimboe@...nel.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Paul Walmsley <pjw@...nel.org>, Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	"Madhavan T. Venkataraman" <madvenka@...ux.microsoft.com>,
	Tiezhu Yang <yangtiezhu@...ngson.cn>,
	Ard Biesheuvel <ardb@...nel.org>, loongarch@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	linux-riscv@...ts.infradead.org, linux-efi@...r.kernel.org,
	linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] efistub: Only link libstub to final vmlinux

On Sat, Nov 15, 2025 at 11:16:42AM +0800, Huacai Chen wrote:
> On Wed, Nov 12, 2025 at 2:00 AM Josh Poimboeuf <jpoimboe@...nel.org> wrote:
> >
> > On Mon, Nov 10, 2025 at 03:00:00PM +0800, Huacai Chen wrote:
> > > On Mon, Nov 10, 2025 at 9:19 AM Tiezhu Yang <yangtiezhu@...ngson.cn> wrote:
> > > > If I understand correctly, I should modify this patch to remove the
> > > > changes of arm and riscv for now, do the changes only when there is
> > > > a real problem or requirement some day, right? If no more comments,
> > > > I will send v3 later.
> > >
> > > Now everyone involved agrees that the efistub code is correct, so the
> > > proper solution is to fix the compiler.
> >
> > Hm?  I don't see how it's a compiler bug.  It's really just an objtool
> > limitation.
> >
> > > Changing efistub code and changing objtool (ignore __efistub prefix)
> > > are both workarounds, but I think changing objtool is a little more
> > > reasonable. Maybe Josh has different ideas?
> >
> > I thought the conversation had converged on what Tiezhu mentioned above,
> > which is to skip objtool on libstub for loongarch, but leave the other
> > arches alone.  That way objtool behavior is consistent between loongarch
> > and x86, and objtool doesn't need to ignore any prefixes.
> >
> > So basically, the v2 patch minus the arm64/riscv changes.
> 
> Hi, ARM64 and RISC-V maintainers,
> 
> Would you mind that this patch modifies the three architectures
> together (they are exactly the same style now)?
> 
> Madhavan is the author of ARM64's objtool, I think your opinion is
> also very important.

arm64 doesn't (yet) use objtool.

I defer to Ard on anything relating to the arm64 efistub. Reading the
start of this thread, it doesn't look like he's convinced and I'm not
surprised if it's purely an issue with objtool.

Will