From 8326ac05ee8841e625a6a54d225242eec579fa13 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Mon, 25 Jul 2022 23:46:47 +0200 Subject: [PATCH] rust: add `bindings` crate MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This crate contains the bindings to the C side of the kernel. Calling C (in general, FFI) is assumed to be unsafe in Rust and, in many cases, this is accurate. For instance, virtually all C functions that take a pointer are unsafe since, typically, it will be dereferenced at some point (and in most cases there is no way for the callee to check its validity beforehand). Since one of the goals of using Rust in the kernel is precisely to avoid unsafe code in "leaf" kernel modules (e.g. drivers), these bindings should not be used directly by them. Instead, these bindings need to be wrapped into safe abstractions. These abstractions provide a safe API that kernel modules can use. In this way, unsafe code in kernel modules is minimized. Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Finn Behrens Signed-off-by: Finn Behrens Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Sven Van Asbroeck Signed-off-by: Sven Van Asbroeck Co-developed-by: Gary Guo Signed-off-by: Gary Guo Co-developed-by: Maciej Falkowski Signed-off-by: Maciej Falkowski Co-developed-by: Jiapeng Chong Signed-off-by: Jiapeng Chong Co-developed-by: Björn Roy Baron Signed-off-by: Björn Roy Baron Signed-off-by: Miguel Ojeda --- rust/bindings/bindings_helper.h | 13 ++++++++ rust/bindings/lib.rs | 53 +++++++++++++++++++++++++++++++++ 2 files changed, 66 insertions(+) create mode 100644 rust/bindings/bindings_helper.h create mode 100644 rust/bindings/lib.rs diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h new file mode 100644 index 000000000000..c48bc284214a --- /dev/null +++ b/rust/bindings/bindings_helper.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Header that contains the code (mostly headers) for which Rust bindings + * will be automatically generated by `bindgen`. + * + * Sorted alphabetically. + */ + +#include + +/* `bindgen` gets confused at certain things. */ +const gfp_t BINDINGS_GFP_KERNEL = GFP_KERNEL; +const gfp_t BINDINGS___GFP_ZERO = __GFP_ZERO; diff --git a/rust/bindings/lib.rs b/rust/bindings/lib.rs new file mode 100644 index 000000000000..6c50ee62c56b --- /dev/null +++ b/rust/bindings/lib.rs @@ -0,0 +1,53 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Bindings. +//! +//! Imports the generated bindings by `bindgen`. +//! +//! This crate may not be directly used. If you need a kernel C API that is +//! not ported or wrapped in the `kernel` crate, then do so first instead of +//! using this crate. + +#![no_std] +#![feature(core_ffi_c)] +// See . +#![cfg_attr(test, allow(deref_nullptr))] +#![cfg_attr(test, allow(unaligned_references))] +#![cfg_attr(test, allow(unsafe_op_in_unsafe_fn))] +#![allow( + clippy::all, + missing_docs, + non_camel_case_types, + non_upper_case_globals, + non_snake_case, + improper_ctypes, + unreachable_pub, + unsafe_op_in_unsafe_fn +)] + +mod bindings_raw { + // Use glob import here to expose all helpers. + // Symbols defined within the module will take precedence to the glob import. + pub use super::bindings_helper::*; + include!(concat!( + env!("OBJTREE"), + "/rust/bindings/bindings_generated.rs" + )); +} + +// When both a directly exposed symbol and a helper exists for the same function, +// the directly exposed symbol is preferred and the helper becomes dead code, so +// ignore the warning here. +#[allow(dead_code)] +mod bindings_helper { + // Import the generated bindings for types. + include!(concat!( + env!("OBJTREE"), + "/rust/bindings/bindings_helpers_generated.rs" + )); +} + +pub use bindings_raw::*; + +pub const GFP_KERNEL: gfp_t = BINDINGS_GFP_KERNEL; +pub const __GFP_ZERO: gfp_t = BINDINGS___GFP_ZERO;