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Message-Id: <20220927131518.30000-10-ojeda@kernel.org>
Date: Tue, 27 Sep 2022 15:14:40 +0200
From: Miguel Ojeda <ojeda@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: rust-for-linux@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-fsdevel@...r.kernel.org, patches@...ts.linux.dev,
Jarkko Sakkinen <jarkko@...nel.org>,
Miguel Ojeda <ojeda@...nel.org>,
Kees Cook <keescook@...omium.org>,
Alex Gaynor <alex.gaynor@...il.com>,
Wedson Almeida Filho <wedsonaf@...gle.com>,
Sven Van Asbroeck <thesven73@...il.com>,
Gary Guo <gary@...yguo.net>, Boqun Feng <boqun.feng@...il.com>,
Björn Roy Baron <bjorn3_gh@...tonmail.com>
Subject: [PATCH v10 09/27] rust: add `compiler_builtins` crate
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.
Reviewed-by: Kees Cook <keescook@...omium.org>
Co-developed-by: Alex Gaynor <alex.gaynor@...il.com>
Signed-off-by: Alex Gaynor <alex.gaynor@...il.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@...gle.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@...gle.com>
Co-developed-by: Sven Van Asbroeck <thesven73@...il.com>
Signed-off-by: Sven Van Asbroeck <thesven73@...il.com>
Co-developed-by: Gary Guo <gary@...yguo.net>
Signed-off-by: Gary Guo <gary@...yguo.net>
Signed-off-by: Miguel Ojeda <ojeda@...nel.org>
---
rust/compiler_builtins.rs | 63 +++++++++++++++++++++++++++++++++++++++
1 file changed, 63 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..f8f39a3e6855
--- /dev/null
+++ b/rust/compiler_builtins.rs
@@ -0,0 +1,63 @@
+// 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 128-bit integers 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!("`f32` should not be used", {
+ __eqsf2,
+ __gesf2,
+ __lesf2,
+ __nesf2,
+ __unordsf2,
+});
+
+define_panicking_intrinsics!("`f64` should not be used", {
+ __unorddf2,
+});
+
+define_panicking_intrinsics!("`i128` should not be used", {
+ __ashrti3,
+ __muloti4,
+ __multi3,
+});
+
+define_panicking_intrinsics!("`u128` should not be used", {
+ __ashlti3,
+ __lshrti3,
+ __udivmodti4,
+ __udivti3,
+ __umodti3,
+});
--
2.37.3
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