From: Kees Cook <kees@kernel•org>
To: Linus Walleij <linus.walleij@linaro•org>
Cc: Sami Tolvanen <samitolvanen@google•com>,
Nathan Chancellor <nathan@kernel•org>,
Alexander Lobakin <aleksander.lobakin@intel•com>,
"David S. Miller" <davem@davemloft•net>,
Eric Dumazet <edumazet@google•com>,
Jakub Kicinski <kuba@kernel•org>, Paolo Abeni <pabeni@redhat•com>,
Simon Horman <horms@kernel•org>,
Nick Desaulniers <nick.desaulniers+lkml@gmail•com>,
Bill Wendling <morbo@google•com>,
Justin Stitt <justinstitt@google•com>,
Russell King <linux@armlinux•org.uk>,
Tony Nguyen <anthony.l.nguyen@intel•com>,
Michal Kubiak <michal.kubiak@intel•com>,
linux-kernel@vger•kernel.org, llvm@lists•linux.dev,
linux-arm-kernel@lists•infradead.org, netdev@vger•kernel.org,
intel-wired-lan@lists•osuosl.org
Subject: Re: [PATCH 2/3] ARM: Select ARCH_USES_CFI_GENERIC_LLVM_PASS
Date: Wed, 29 Oct 2025 20:04:05 -0700 [thread overview]
Message-ID: <202510292002.10FDB135C3@keescook> (raw)
In-Reply-To: <CACRpkdaeOYEcK9w1oy59WBqjNrK7q5zT2rzg8pHgDdZdKWVKZg@mail.gmail.com>
On Mon, Oct 27, 2025 at 11:56:21PM +0100, Linus Walleij wrote:
> On Mon, Oct 27, 2025 at 4:54 PM Sami Tolvanen <samitolvanen@google•com> wrote:
> > On Sat, Oct 25, 2025 at 1:53 PM Nathan Chancellor <nathan@kernel•org> wrote:
> > >
> > > Prior to clang 22.0.0 [1], ARM did not have an architecture specific
> > > kCFI bundle lowering in the backend, which may cause issues. Select
> > > CONFIG_ARCH_USES_CFI_GENERIC_LLVM_PASS to enable use of __nocfi_generic.
> > >
> > > Link: https://github.com/llvm/llvm-project/commit/d130f402642fba3d065aacb506cb061c899558de [1]
> > > Link: https://github.com/ClangBuiltLinux/linux/issues/2124
> > > Signed-off-by: Nathan Chancellor <nathan@kernel•org>
>
> I didn't know Kees stepped in and fixed this, christmas comes
> early this year! I had it on my TODO to do this or get someone to
> do this, but now it turns out I don't have to.
>
> > > + # https://github.com/llvm/llvm-project/commit/d130f402642fba3d065aacb506cb061c899558de
> > > + select ARCH_USES_CFI_GENERIC_LLVM_PASS if CLANG_VERSION < 220000
> >
> > Instead of working around issues with the generic pass, would it make
> > more sense to just disable arm32 CFI with older Clang versions
> > entirely? Linus, any thoughts?
>
> We have people using this with the default compilers that come with
> Debiand and Fedora. I would say as soon as the latest release of
> the major distributions supports this, we can drop support for older
> compilers.
Okay, it seems like the consensus is to take this series so we don't
break existing users, even if they are rare.
Unless someone screams, I'll take this via the hardening tree...
--
Kees Cook
next prev parent reply other threads:[~2025-10-30 3:04 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-25 20:53 [PATCH 0/3] Resolve ARM kCFI build failure in idpf xsk.c Nathan Chancellor
2025-10-25 20:53 ` [PATCH 1/3] compiler_types: Introduce __nocfi_generic Nathan Chancellor
2025-10-25 20:53 ` [PATCH 2/3] ARM: Select ARCH_USES_CFI_GENERIC_LLVM_PASS Nathan Chancellor
2025-10-27 15:53 ` Sami Tolvanen
2025-10-27 20:59 ` Nathan Chancellor
2025-10-27 22:56 ` Linus Walleij
2025-10-28 17:52 ` Nathan Chancellor
2025-10-28 18:14 ` Sami Tolvanen
2025-10-30 3:04 ` Kees Cook [this message]
2025-10-25 20:53 ` [PATCH 3/3] libeth: xdp: Disable generic kCFI pass for libeth_xdp_tx_xmit_bulk() Nathan Chancellor
2025-10-27 11:09 ` Przemek Kitszel
2025-10-27 20:36 ` Nathan Chancellor
2025-10-27 14:59 ` Alexander Lobakin
2025-10-27 20:54 ` Nathan Chancellor
2025-10-28 16:29 ` Alexander Lobakin
2025-10-28 22:01 ` Nathan Chancellor
2025-10-28 7:31 ` [Intel-wired-lan] " Loktionov, Aleksandr
2025-10-30 3:06 ` [PATCH 0/3] Resolve ARM kCFI build failure in idpf xsk.c Kees Cook
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