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From: Gary Guo <gary@garyguo.net>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Miguel Ojeda <ojeda@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jarkko Sakkinen <jarkko@kernel.org>,
	Alex Gaynor <alex.gaynor@gmail.com>,
	Wedson Almeida Filho <wedsonaf@google.com>,
	Sven Van Asbroeck <thesven73@gmail.com>
Subject: Re: [PATCH v7 06/25] rust: add `compiler_builtins` crate
Date: Tue, 24 May 2022 00:41:56 +0100	[thread overview]
Message-ID: <20220524004156.0000790e@garyguo.net> (raw)
In-Reply-To: <CAKwvOd=mFhxjKRP_qt3Yu69dj_P6VUMSUSQm7fY6yS2bsO8Y2w@mail.gmail.com>

On Mon, 23 May 2022 11:37:16 -0700
Nick Desaulniers <ndesaulniers@google.com> wrote:

> Also, I'm not sure my concern about explicit build failures for C code
> was ever addressed?  We have a constant problem with `long long`
> division on ARCH=arm32 and ARCH=i386 in C code.
> https://lore.kernel.org/lkml/CAKwvOdk+A2PBdjSFVUhj4xyCGCKujtej1uPgywQgrKPiK2ksPw@mail.gmail.com/
>
> > +#[cfg(target_arch = "arm")]
> > +define_panicking_intrinsics!("`u64` division/modulo should not be
> > used", {
> > +    __aeabi_uldivmod,
> > +    __mulodi4,
> > +});

Starting in LLVM 14 (used in Rust 1.60+), __mulodi4 will no longer be
generated. So that can be removed.

As for __aeabi_uldivmod, is there any reason that it can't just be
defined in arch/arm/lib? There are quite a few __aeabi functions already
defined there.

The source of __aeabi_uldivmod in compiler-rt seems quite simple, just
delegating to __uldivmoddi4. I think just changing that to
div64_u64_rem should do the job?

https://android.googlesource.com/toolchain/compiler-rt/+/release_32/lib/arm/aeabi_uldivmod.S

- Gary

  reply	other threads:[~2022-05-23 23:42 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 01/25] kallsyms: avoid hardcoding the buffer size Miguel Ojeda
2022-05-23 19:45   ` Jarkko Sakkinen
2022-05-23 19:55     ` Jarkko Sakkinen
2022-05-24 16:21     ` Miguel Ojeda
2022-05-26  4:54       ` Jarkko Sakkinen
2022-05-23  2:01 ` [PATCH v7 02/25] kallsyms: support "big" kernel symbols Miguel Ojeda
2022-05-23 20:30   ` Jarkko Sakkinen
2022-05-23  2:01 ` [PATCH v7 03/25] kallsyms: increase maximum kernel symbol length to 512 Miguel Ojeda
2022-05-23 20:31   ` Jarkko Sakkinen
2022-05-24 18:07     ` Miguel Ojeda
2022-05-27 16:25       ` Jarkko Sakkinen
2022-05-30 13:01         ` Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 04/25] kunit: take `kunit_assert` as `const` Miguel Ojeda
2022-05-23 17:15   ` Daniel Latypov
2022-05-23 18:14     ` Shuah Khan
2022-05-24 12:37       ` Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 05/25] rust: add C helpers Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 06/25] rust: add `compiler_builtins` crate Miguel Ojeda
2022-05-23 18:37   ` Nick Desaulniers
2022-05-23 23:41     ` Gary Guo [this message]
2022-05-25 21:29       ` Nick Desaulniers
2022-05-24 12:29     ` Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 07/25] rust: import upstream `alloc` crate Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 08/25] rust: adapt `alloc` crate to the kernel Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 09/25] rust: add `build_error` crate Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 10/25] rust: add `macros` crate Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 11/25] rust: add `kernel` crate's `sync` module Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 12/25] rust: add `kernel` crate Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 13/25] rust: export generated symbols Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 14/25] vsprintf: add new `%pA` format specifier Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 15/25] scripts: checkpatch: diagnose uses of `%pA` in the C side Miguel Ojeda
2022-05-23  2:17   ` Joe Perches
2022-05-24 16:35     ` Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 16/25] scripts: checkpatch: enable language-independent checks for Rust Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 17/25] scripts: add `rustdoc_test_{builder,gen}.py` scripts Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 18/25] scripts: add `generate_rust_analyzer.py` scripts Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 19/25] scripts: decode_stacktrace: demangle Rust symbols Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 20/25] docs: add Rust documentation Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 21/25] Kbuild: add Rust support Miguel Ojeda
2022-05-23 18:44   ` Nick Desaulniers
2022-05-24 15:12     ` Miguel Ojeda
2022-05-25 22:25   ` Nick Desaulniers
2022-05-30 13:39     ` Miguel Ojeda
2022-07-16  8:21   ` Masahiro Yamada
2022-07-16  8:57     ` Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 22/25] samples: add Rust examples Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 23/25] MAINTAINERS: Rust Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 24/25] [RFC] drivers: gpio: PrimeCell PL061 in Rust Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 25/25] [RFC] drivers: android: Binder IPC " Miguel Ojeda
2022-07-16 12:42 ` [PATCH v7 00/25] Rust support Conor Dooley
2022-07-16 13:36   ` Miguel Ojeda
2022-07-16 13:51     ` Conor.Dooley
2022-07-16 13:56       ` Miguel Ojeda

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