projects/linux·blob v6.10 · refs

138 lines · 3.8 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(coerce_unsized)]
16#![feature(dispatch_from_dyn)]
17#![feature(new_uninit)]
18#![feature(receiver_trait)]
19#![feature(unsize)]
20
21// Ensure conditional compilation based on the kernel configuration works;
22// otherwise we may silently break things like initcall handling.
23#[cfg(not(CONFIG_RUST))]
24compile_error!("Missing kernel configuration for conditional compilation");
25
26// Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate).
27extern crate self as kernel;
28
29pub mod alloc;
30mod build_assert;
31pub mod error;
32pub mod init;
33pub mod ioctl;
34#[cfg(CONFIG_KUNIT)]
35pub mod kunit;
36#[cfg(CONFIG_NET)]
37pub mod net;
38pub mod prelude;
39pub mod print;
40mod static_assert;
41#[doc(hidden)]
42pub mod std_vendor;
43pub mod str;
44pub mod sync;
45pub mod task;
46pub mod time;
47pub mod types;
48pub mod workqueue;
49
50#[doc(hidden)]
51pub use bindings;
52pub use macros;
53pub use uapi;
54
55#[doc(hidden)]
56pub use build_error::build_error;
57
58/// Prefix to appear before log messages printed from within the `kernel` crate.
59const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
60
61/// The top level entrypoint to implementing a kernel module.
62///
63/// For any teardown or cleanup operations, your type may implement [`Drop`].
64pub trait Module: Sized + Sync + Send {
65 /// Called at module initialization time.
66 ///
67 /// Use this method to perform whatever setup or registration your module
68 /// should do.
69 ///
70 /// Equivalent to the `module_init` macro in the C API.
71 fn init(module: &'static ThisModule) -> error::Result<Self>;
72}
73
74/// Equivalent to `THIS_MODULE` in the C API.
75///
76/// C header: [`include/linux/export.h`](srctree/include/linux/export.h)
77pub struct ThisModule(*mut bindings::module);
78
79// SAFETY: `THIS_MODULE` may be used from all threads within a module.
80unsafe impl Sync for ThisModule {}
81
82impl ThisModule {
83 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
84 ///
85 /// # Safety
86 ///
87 /// The pointer must be equal to the right `THIS_MODULE`.
88 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
89 ThisModule(ptr)
90 }
91
92 /// Access the raw pointer for this module.
93 ///
94 /// It is up to the user to use it correctly.
95 pub const fn as_ptr(&self) -> *mut bindings::module {
96 self.0
97 }
98}
99
100#[cfg(not(any(testlib, test)))]
101#[panic_handler]
102fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
103 pr_emerg!("{}\n", info);
104 // SAFETY: FFI call.
105 unsafe { bindings::BUG() };
106}
107
108/// Produces a pointer to an object from a pointer to one of its fields.
109///
110/// # Safety
111///
112/// The pointer passed to this macro, and the pointer returned by this macro, must both be in
113/// bounds of the same allocation.
114///
115/// # Examples
116///
117/// ```
118/// # use kernel::container_of;
119/// struct Test {
120/// a: u64,
121/// b: u32,
122/// }
123///
124/// let test = Test { a: 10, b: 20 };
125/// let b_ptr = &test.b;
126/// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be
127/// // in-bounds of the same allocation as `b_ptr`.
128/// let test_alias = unsafe { container_of!(b_ptr, Test, b) };
129/// assert!(core::ptr::eq(&test, test_alias));
130/// ```
131#[macro_export]
132macro_rules! container_of {
133 ($ptr:expr, $type:ty, $($f:tt)*) => {{
134 let ptr = $ptr as *const _ as *const u8;
135 let offset: usize = ::core::mem::offset_of!($type, $($f)*);
136 ptr.sub(offset) as *const $type
137 }}
138}