From: Miguel Ojeda <ojeda@xxxxxxxxxx> 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. We also need a helpers C source file to contain some forwarders to C macros and inlined functions. For the moment, we only need it to call the `BUG()` macro, but we will be adding more later. This also allows us to build `core` from Rust's standard library. Co-developed-by: Alex Gaynor <alex.gaynor@xxxxxxxxx> Signed-off-by: Alex Gaynor <alex.gaynor@xxxxxxxxx> Co-developed-by: Geoffrey Thomas <geofft@xxxxxxxxxxxxx> Signed-off-by: Geoffrey Thomas <geofft@xxxxxxxxxxxxx> Co-developed-by: Finn Behrens <me@xxxxxxxxx> Signed-off-by: Finn Behrens <me@xxxxxxxxx> Co-developed-by: Adam Bratschi-Kaye <ark.email@xxxxxxxxx> Signed-off-by: Adam Bratschi-Kaye <ark.email@xxxxxxxxx> Co-developed-by: Wedson Almeida Filho <wedsonaf@xxxxxxxxxx> Signed-off-by: Wedson Almeida Filho <wedsonaf@xxxxxxxxxx> Signed-off-by: Miguel Ojeda <ojeda@xxxxxxxxxx> --- rust/Makefile | 3 + rust/compiler_builtins.rs | 146 ++++++++++++++++++++++++++++++++++++++ rust/helpers.c | 8 +++ 3 files changed, 157 insertions(+) create mode 100644 rust/compiler_builtins.rs create mode 100644 rust/helpers.c diff --git a/rust/Makefile b/rust/Makefile index ba4b13e4fc7f..5b96462b4fef 100644 --- a/rust/Makefile +++ b/rust/Makefile @@ -1,5 +1,8 @@ # SPDX-License-Identifier: GPL-2.0 +obj-$(CONFIG_RUST) += core.o compiler_builtins.o helpers.o +extra-$(CONFIG_RUST) += exports_core_generated.h + RUSTDOC = rustdoc quiet_cmd_rustdoc = RUSTDOC $< diff --git a/rust/compiler_builtins.rs b/rust/compiler_builtins.rs new file mode 100644 index 000000000000..01f2d905e15f --- /dev/null +++ b/rust/compiler_builtins.rs @@ -0,0 +1,146 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Our own `compiler_builtins`. +//! +//! Rust provides [`compiler_builtins`] as a port of LLVM's [`compiler-rt`]. +//! Since we do not need the vast majority of them, we avoid the dependency +//! by providing this file. +//! +//! At the moment, some builtins are required that should not be. For instance, +//! [`core`] has floating-point functionality which we should not be compiling +//! in. For the moment, we define them to [`panic!`] at runtime for simplicity. +//! These are actually a superset of the ones we actually need to define, +//! but it seems simpler to ban entire categories at once. In the future, +//! we might be able to remove all this by providing our own custom [`core`] +//! etc., or perhaps [`core`] itself might provide `cfg` options to disable +//! enough functionality to avoid requiring some of these. +//! +//! In any case, all these symbols are weakened to ensure we do not override +//! those that may be provided by the rest of the kernel. +//! +//! [`compiler_builtins`]: https://github.com/rust-lang/compiler-builtins +//! [`compiler-rt`]: https://compiler-rt.llvm.org/ + +#![feature(compiler_builtins)] +#![compiler_builtins] +#![no_builtins] +#![no_std] +#![deny(clippy::complexity)] +#![deny(clippy::correctness)] +#![deny(clippy::perf)] +#![deny(clippy::style)] + +macro_rules! define_panicking_intrinsics( + ($reason: tt, { $($ident: ident, )* }) => { + $( + #[doc(hidden)] + #[no_mangle] + pub extern "C" fn $ident() { + panic!($reason); + } + )* + } +); + +define_panicking_intrinsics!("non-inline stack probes should not be used", { + __rust_probestack, +}); + +define_panicking_intrinsics!("`f32` should not be used", { + __addsf3, + __addsf3vfp, + __divsf3, + __divsf3vfp, + __eqsf2, + __eqsf2vfp, + __fixsfdi, + __fixsfsi, + __fixsfti, + __fixunssfdi, + __fixunssfsi, + __fixunssfti, + __floatdisf, + __floatsisf, + __floattisf, + __floatundisf, + __floatunsisf, + __floatuntisf, + __gesf2, + __gesf2vfp, + __gtsf2, + __gtsf2vfp, + __lesf2, + __lesf2vfp, + __ltsf2, + __ltsf2vfp, + __mulsf3, + __mulsf3vfp, + __nesf2, + __nesf2vfp, + __powisf2, + __subsf3, + __subsf3vfp, + __unordsf2, +}); + +define_panicking_intrinsics!("`f64` should not be used", { + __adddf3, + __adddf3vfp, + __divdf3, + __divdf3vfp, + __eqdf2, + __eqdf2vfp, + __fixdfdi, + __fixdfsi, + __fixdfti, + __fixunsdfdi, + __fixunsdfsi, + __fixunsdfti, + __floatdidf, + __floatsidf, + __floattidf, + __floatundidf, + __floatunsidf, + __floatuntidf, + __gedf2, + __gedf2vfp, + __gtdf2, + __gtdf2vfp, + __ledf2, + __ledf2vfp, + __ltdf2, + __ltdf2vfp, + __muldf3, + __muldf3vfp, + __nedf2, + __nedf2vfp, + __powidf2, + __subdf3, + __subdf3vfp, + __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, +}); + +extern "C" { + fn rust_helper_BUG() -> !; +} + +#[panic_handler] +fn panic(_info: &core::panic::PanicInfo) -> ! { + unsafe { + rust_helper_BUG(); + } +} diff --git a/rust/helpers.c b/rust/helpers.c new file mode 100644 index 000000000000..5c2346dd379b --- /dev/null +++ b/rust/helpers.c @@ -0,0 +1,8 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/bug.h> + +void rust_helper_BUG(void) +{ + BUG(); +} -- 2.17.1
