linux-kernel - Re: [PATCH 3/3] rust: Enable for MIPS

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

Message-ID: <CANiq72m5iFcqRU_qdUCZkoV8ayPhtQQq3TTEDRUYfMEsnNqTDg@mail.gmail.com>
Date: Tue, 3 Sep 2024 20:17:04 +0200
From: Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
To: Jiaxun Yang <jiaxun.yang@...goat.com>
Cc: Masahiro Yamada <masahiroy@...nel.org>, Nathan Chancellor <nathan@...nel.org>, 
	Nicolas Schier <nicolas@...sle.eu>, Richard Weinberger <richard@....at>, 
	Anton Ivanov <anton.ivanov@...bridgegreys.com>, Johannes Berg <johannes@...solutions.net>, 
	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
	"H. Peter Anvin" <hpa@...or.com>, Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>, 
	Wedson Almeida Filho <wedsonaf@...il.com>, Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>, 
	Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
	Benno Lossin <benno.lossin@...ton.me>, Andreas Hindborg <a.hindborg@...sung.com>, 
	Alice Ryhl <aliceryhl@...gle.com>, Thomas Bogendoerfer <tsbogend@...ha.franken.de>, 
	Steven Rostedt <rostedt@...dmis.org>, Masami Hiramatsu <mhiramat@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, Jonathan Corbet <corbet@....net>, Alex Shi <alexs@...nel.org>, 
	Yanteng Si <siyanteng@...ngson.cn>, Nick Desaulniers <ndesaulniers@...gle.com>, 
	Bill Wendling <morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>, linux-kbuild@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-um@...ts.infradead.org, 
	rust-for-linux@...r.kernel.org, 
	"linux-mips@...r.kernel.org" <linux-mips@...r.kernel.org>, linux-trace-kernel@...r.kernel.org, 
	linux-doc@...r.kernel.org, llvm@...ts.linux.dev
Subject: Re: [PATCH 3/3] rust: Enable for MIPS

On Tue, Sep 3, 2024 at 7:53 PM Jiaxun Yang <jiaxun.yang@...goat.com> wrote:
>
> Thanks for your review!

You're welcome!

> Triples defined for MIPS bare-metal target is surprisingly lacking, we do have
> little-endian 32-bit bare-metal target mipsel-unknown-none but big-endian and
> 64 bit variants are missing.

Hmm... Sorry if this may be too naive, since I have no expertise on
MIPS, but I see some triples that match the LLVM ones you specify in
the patch:

    rustc --print target-list | grep mips

> Also, those triples all assumed +mips32r2 as baseline ISA, but kernel actually needs
> some other ISA variant features.

I guess you mean you are getting the warning about the
unknown/unstable feature passed to the backend? i.e. `rustc` knows
about those LLVM ones and forwards them when enabled via
`-Ctarget-feature` (with a warning):

    rustc --target mips64-unknown-linux-gnuabi64 --print target-features

So they would need to be added to the list at [1] (or targeted flags created).

Until those do not emit a warning, it is fine using the `target.json`,
but I wanted to understand if there is something else you may need,
since we will need to eventually avoid the `target.json`, so it is
best asking upstream as soon as possible.

Thanks!

[1] https://github.com/rust-lang/rust/blob/d6c8169c186ab16a3404cd0d0866674018e8a19e/compiler/rustc_target/src/target_features.rs#L368

Cheers,
Miguel