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From: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date: Tue, 9 Apr 2024 17:55:04 +0200
Message-ID: <CANiq72mzMBDJnkSW_EDaVdAEHbWtsLL6-unY0R2nOpexhHbfhg@mail.gmail.com>
Subject: Re: [PATCH v2] rust: add flags for shadow call stack sanitizer
To: Will Deacon <will@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>, Catalin Marinas <catalin.marinas@arm.com>, 
	Jamie Cunliffe <Jamie.Cunliffe@arm.com>, Sami Tolvanen <samitolvanen@google.com>, 
	Masahiro Yamada <masahiroy@kernel.org>, Nathan Chancellor <nathan@kernel.org>, 
	Nicolas Schier <nicolas@fjasle.eu>, Ard Biesheuvel <ardb@kernel.org>, Marc Zyngier <maz@kernel.org>, 
	Mark Rutland <mark.rutland@arm.com>, Mark Brown <broonie@kernel.org>, 
	Nick Desaulniers <ndesaulniers@google.com>, Kees Cook <keescook@chromium.org>, 
	Miguel Ojeda <ojeda@kernel.org>, Alex Gaynor <alex.gaynor@gmail.com>, 
	Wedson Almeida Filho <wedsonaf@gmail.com>, Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>, 
	=?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>, 
	Benno Lossin <benno.lossin@proton.me>, Andreas Hindborg <a.hindborg@samsung.com>, 
	Valentin Obst <kernel@valentinobst.de>, linux-kbuild@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, 
	rust-for-linux@vger.kernel.org
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On Tue, Apr 9, 2024 at 12:31=E2=80=AFPM Will Deacon <will@kernel.org> wrote=
:
>
> I think we have time to do this properly, like we did for the clang
> enablement a few years ago. In hindsight, avoiding hacks for the early
> toolchains back then was a really good idea because it meant we could
> rely on a solid baseline set of compiler features from the start.

Yeah, it sounds fair, thanks!

After the warning is fixed (i.e. `-Zfixed-x18` or similar is
implemented etc.), I would recommend adding support to the kernel for
the `-Z` (unstable) flags, similar to this patch, in order to test
them easily and getting `rustc` to stabilize them. Then the only
change required should be a name change to `-C` or similar.

Cheers,
Miguel