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authorMiguel Ojeda <ojeda@kernel.org>2021-07-03 16:54:11 +0200
committerMiguel Ojeda <ojeda@kernel.org>2022-09-28 08:58:00 +0200
commitdb958dcf88e512c55595a30944467cb5bf3647fb (patch)
treea3a3f8046146dca4aca4d2dcbf991b4972355986 /rust
parent057b8d2571071da05d06810ca70f26c6316f6ea7 (diff)
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@chromium.org> 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>
Diffstat (limited to 'rust')
-rw-r--r--rust/compiler_builtins.rs63
1 files changed, 63 insertions, 0 deletions
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,
+});