rust-for-linux.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Miguel Ojeda <ojeda@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: rust-for-linux@vger.kernel.org, linux-kbuild@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	Miguel Ojeda <ojeda@kernel.org>,
	Alex Gaynor <alex.gaynor@gmail.com>,
	Wedson Almeida Filho <wedsonaf@google.com>,
	Sven Van Asbroeck <thesven73@gmail.com>,
	Gary Guo <gary@garyguo.net>
Subject: [PATCH v3 05/19] rust: add `compiler_builtins` crate
Date: Mon, 17 Jan 2022 06:33:35 +0100	[thread overview]
Message-ID: <20220117053349.6804-6-ojeda@kernel.org> (raw)
In-Reply-To: <20220117053349.6804-1-ojeda@kernel.org>

Rust provides `compiler_builtins` as a port of LLVM's `compiler-rt`.
Since we do not need the vast majority of them, we avoid the
dependency by providing our own crate.

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/compiler_builtins.rs | 57 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 rust/compiler_builtins.rs

diff --git a/rust/compiler_builtins.rs b/rust/compiler_builtins.rs
new file mode 100644
index 000000000000..a5a0be72591b
--- /dev/null
+++ b/rust/compiler_builtins.rs
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Our own `compiler_builtins`.
+//!
+//! Rust provides [`compiler_builtins`] as a port of LLVM's [`compiler-rt`].
+//! Since we do not need the vast majority of them, we avoid the dependency
+//! by providing this file.
+//!
+//! At the moment, some builtins are required that should not be. For instance,
+//! [`core`] has floating-point functionality which we should not be compiling
+//! in. We will work with upstream [`core`] to provide feature flags to disable
+//! the parts we do not need. For the moment, we define them to [`panic!`] at
+//! runtime for simplicity to catch mistakes, instead of performing surgery
+//! on `core.o`.
+//!
+//! In any case, all these symbols are weakened to ensure we do not override
+//! those that may be provided by the rest of the kernel.
+//!
+//! [`compiler_builtins`]: https://github.com/rust-lang/compiler-builtins
+//! [`compiler-rt`]: https://compiler-rt.llvm.org/
+
+#![feature(compiler_builtins)]
+#![compiler_builtins]
+#![no_builtins]
+#![no_std]
+
+macro_rules! define_panicking_intrinsics(
+    ($reason: tt, { $($ident: ident, )* }) => {
+        $(
+            #[doc(hidden)]
+            #[no_mangle]
+            pub extern "C" fn $ident() {
+                panic!($reason);
+            }
+        )*
+    }
+);
+
+define_panicking_intrinsics!("`i128` should not be used", {
+    __ashrti3,
+    __muloti4,
+    __multi3,
+});
+
+define_panicking_intrinsics!("`u128` should not be used", {
+    __ashlti3,
+    __lshrti3,
+    __udivmodti4,
+    __udivti3,
+    __umodti3,
+});
+
+#[cfg(target_arch = "arm")]
+define_panicking_intrinsics!("`u64` division/modulo should not be used", {
+    __aeabi_uldivmod,
+    __mulodi4,
+});
-- 
2.34.1


  parent reply	other threads:[~2022-01-17  5:34 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-17  5:33 [PATCH v3 00/19] Rust support Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 01/19] kallsyms: support "big" kernel symbols Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 02/19] kallsyms: increase maximum kernel symbol length to 512 Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 03/19] kallsyms: use the correct buffer size for symbols Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 04/19] rust: add C helpers Miguel Ojeda
2022-01-17  5:33 ` Miguel Ojeda [this message]
2022-01-17  5:33 ` [PATCH v3 07/19] rust: add `build_error` crate Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 08/19] rust: add `macros` crate Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 10/19] rust: export generated symbols Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 11/19] vsprintf: add new `%pA` format specifier Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 12/19] scripts: add `generate_rust_analyzer.py` Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 13/19] scripts: decode_stacktrace: demangle Rust symbols Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 14/19] docs: add Rust documentation Miguel Ojeda
2022-01-18 22:33   ` Jonathan Corbet
2022-01-19 13:58     ` Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 15/19] Kbuild: add Rust support Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 16/19] samples: add Rust examples Miguel Ojeda
2022-01-17  5:33 ` [PATCH v3 17/19] MAINTAINERS: Rust Miguel Ojeda
2022-01-17  5:33 ` [RFC PATCH v3 18/19] drivers: gpio: PrimeCell PL061 in Rust Miguel Ojeda

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220117053349.6804-6-ojeda@kernel.org \
    --to=ojeda@kernel.org \
    --cc=alex.gaynor@gmail.com \
    --cc=gary@garyguo.net \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kbuild@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rust-for-linux@vger.kernel.org \
    --cc=thesven73@gmail.com \
    --cc=torvalds@linux-foundation.org \
    --cc=wedsonaf@google.com \
    --subject='Re: [PATCH v3 05/19] rust: add `compiler_builtins` crate' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).