Received-SPF: pass (google.com: domain of linux-kernel+bounces-62250-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Precedence: bulk
MIME-Version: 1.0
References: <20240117-swiftly-parasail-618d62972d6e@spud> <CANiq72mVKCOAuK4Qe+8AHmpkFwyJsVfx8AqB7ccGi3DYpSSWcw@mail.gmail.com>
 <20240118-implode-delirium-eefdd86e170e@spud> <CANiq72nx1s_nyvPW86jL7eiOxROr18LfOJqNtw8L42CP+gkhRg@mail.gmail.com>
 <20240125-bucked-payroll-47f82077b262@wendy> <CANiq72k7n0aZrifRRU08N8qLkNe+2EZwijZy5sM7M56n2xYHgQ@mail.gmail.com>
 <20240125-lazy-thrower-744aacc6632a@wendy> <CANiq72kb+_utZrYHtoKZQtQazikmkjpVUHpTBcaANizduMF5QQ@mail.gmail.com>
 <20240126-eccentric-jaywalker-3560e2151a92@spud> <CANiq72nu2NXUWYanHZd5EXgX4P_v673EWn6SCRW60Es9naraQQ@mail.gmail.com>
 <20240209-rage-keg-1b2982cd17d9@spud> <CALNs47sRqAbE=u3=_ciO2oge7Afz-6GBBhW+BwcLRET-TsuxTg@mail.gmail.com>
In-Reply-To: <CALNs47sRqAbE=u3=_ciO2oge7Afz-6GBBhW+BwcLRET-TsuxTg@mail.gmail.com>
From: Ramon de C Valle <rcvalle@google.com>
Date: Mon, 12 Feb 2024 11:03:57 -0800
Message-ID: <CAOcBZOSfN8Yefez_Gy_T3_QTAd4HcLzmMCOoR37K2agWD_U_PQ@mail.gmail.com>
Subject: Re: [PATCH v1 0/2] RISC-V: enable rust
To: Trevor Gross <tmgross@umich.edu>
Cc: Conor Dooley <conor@kernel.org>, Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>, 
	Conor Dooley <conor.dooley@microchip.com>, linux-riscv@lists.infradead.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>, 
	Jonathan Corbet <corbet@lwn.net>, Paul Walmsley <paul.walmsley@sifive.com>, 
	Palmer Dabbelt <palmer@dabbelt.com>, Nathan Chancellor <nathan@kernel.org>, 
	Nick Desaulniers <ndesaulniers@google.com>, Tom Rix <trix@redhat.com>, 
	rust-for-linux@vger.kernel.org, linux-doc@vger.kernel.org, 
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev, 
	Matthew Maurer <mmaurer@google.com>, Sami Tolvanen <samitolvanen@google.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Sorry for the late reply. Sami might be the best person to answer
this, but KCFI (not CFI) tests are lowered by passes that are
architecture specific (see https://reviews.llvm.org/D119296), so we'd
need to add support for RISC-V. There is no additional work required
in the Rust compiler besides enabling it for the new target.


On Sat, Feb 10, 2024 at 12:13=E2=80=AFAM Trevor Gross <tmgross@umich.edu> w=
rote:
>
> On Fri, Feb 9, 2024 at 9:18=E2=80=AFAM Conor Dooley <conor@kernel.org> wr=
ote:
> >
> > On Sat, Jan 27, 2024 at 02:46:38PM +0100, Miguel Ojeda wrote:
> > > On Fri, Jan 26, 2024 at 11:01=E2=80=AFPM Conor Dooley <conor@kernel.o=
rg> wrote:
> > > >
> > > > Is that even needed? We already have ARCH_SUPPORTS_CFI_CLANG and AF=
AIU
> > > > rust supports it if clang does, so a second option is superfluous?
> > >
> > > From a quick look, I don't see it enabled in any RISC-V built-in
> > > target in `rustc` yet.
> > >
> > > It may also still be the case that KCFI needs some tweaks for, say,
> > > RISC-V, before the flag actually works, i.e. we couldn't just test th=
e
> > > flag in that case -- Ramon: how likely is it that RISC-V would work i=
f
> > > KCFI works for aarch64 and x86_64?
> >
> > Well, there's been no reply here. I'll do sa you suggested and add a
> > depends on !CFI_CLANG to RUST.
> >
> > Cheers,
> > Conor.
> >
>
> I asked on Zulip and it sounds like Ramon may be out [1]. It
> _probably_ works, but going with a dependency to not be blocked on
> KCFI is probably reasonable for now.
>
> - Trevor
>
> [1]: https://rust-lang.zulipchat.com/#narrow/stream/343119-project-exploi=
t-mitigations/topic/KCFI.20on.20RISC-V.20questions