projects/linux·blob v6.9 · refs

135 lines · 3.7 KiB

1// SPDX-License-Identifier: GPL-2.0
2
3//! The `kernel` crate.
4//!
5//! This crate contains the kernel APIs that have been ported or wrapped for
6//! usage by Rust code in the kernel and is shared by all of them.
7//!
8//! In other words, all the rest of the Rust code in the kernel (e.g. kernel
9//! modules written in Rust) depends on [`core`], [`alloc`] and this crate.
10//!
11//! If you need a kernel C API that is not ported or wrapped yet here, then
12//! do so first instead of bypassing this crate.
13
14#![no_std]
15#![feature(allocator_api)]
16#![feature(coerce_unsized)]
17#![feature(dispatch_from_dyn)]
18#![feature(new_uninit)]
19#![feature(offset_of)]
20#![feature(receiver_trait)]
21#![feature(unsize)]
22
23// Ensure conditional compilation based on the kernel configuration works;
24// otherwise we may silently break things like initcall handling.
25#[cfg(not(CONFIG_RUST))]
26compile_error!("Missing kernel configuration for conditional compilation");
27
28// Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate).
29extern crate self as kernel;
30
31#[cfg(not(test))]
32#[cfg(not(testlib))]
33mod allocator;
34mod build_assert;
35pub mod error;
36pub mod init;
37pub mod ioctl;
38#[cfg(CONFIG_KUNIT)]
39pub mod kunit;
40#[cfg(CONFIG_NET)]
41pub mod net;
42pub mod prelude;
43pub mod print;
44mod static_assert;
45#[doc(hidden)]
46pub mod std_vendor;
47pub mod str;
48pub mod sync;
49pub mod task;
50pub mod time;
51pub mod types;
52pub mod workqueue;
53
54#[doc(hidden)]
55pub use bindings;
56pub use macros;
57pub use uapi;
58
59#[doc(hidden)]
60pub use build_error::build_error;
61
62/// Prefix to appear before log messages printed from within the `kernel` crate.
63const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
64
65/// The top level entrypoint to implementing a kernel module.
66///
67/// For any teardown or cleanup operations, your type may implement [`Drop`].
68pub trait Module: Sized + Sync + Send {
69 /// Called at module initialization time.
70 ///
71 /// Use this method to perform whatever setup or registration your module
72 /// should do.
73 ///
74 /// Equivalent to the `module_init` macro in the C API.
75 fn init(module: &'static ThisModule) -> error::Result<Self>;
76}
77
78/// Equivalent to `THIS_MODULE` in the C API.
79///
80/// C header: [`include/linux/export.h`](srctree/include/linux/export.h)
81pub struct ThisModule(*mut bindings::module);
82
83// SAFETY: `THIS_MODULE` may be used from all threads within a module.
84unsafe impl Sync for ThisModule {}
85
86impl ThisModule {
87 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
88 ///
89 /// # Safety
90 ///
91 /// The pointer must be equal to the right `THIS_MODULE`.
92 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
93 ThisModule(ptr)
94 }
95}
96
97#[cfg(not(any(testlib, test)))]
98#[panic_handler]
99fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
100 pr_emerg!("{}\n", info);
101 // SAFETY: FFI call.
102 unsafe { bindings::BUG() };
103}
104
105/// Produces a pointer to an object from a pointer to one of its fields.
106///
107/// # Safety
108///
109/// The pointer passed to this macro, and the pointer returned by this macro, must both be in
110/// bounds of the same allocation.
111///
112/// # Examples
113///
114/// ```
115/// # use kernel::container_of;
116/// struct Test {
117/// a: u64,
118/// b: u32,
119/// }
120///
121/// let test = Test { a: 10, b: 20 };
122/// let b_ptr = &test.b;
123/// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be
124/// // in-bounds of the same allocation as `b_ptr`.
125/// let test_alias = unsafe { container_of!(b_ptr, Test, b) };
126/// assert!(core::ptr::eq(&test, test_alias));
127/// ```
128#[macro_export]
129macro_rules! container_of {
130 ($ptr:expr, $type:ty, $($f:tt)*) => {{
131 let ptr = $ptr as *const _ as *const u8;
132 let offset: usize = ::core::mem::offset_of!($type, $($f)*);
133 ptr.sub(offset) as *const $type
134 }}
135}