1 // SPDX-License-Identifier: GPL-2.0
3 //! The `kernel` crate.
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.
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.
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.
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)]
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))]
26 compile_error!("Missing kernel configuration for conditional compilation");
28 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate).
29 extern crate self as kernel;
60 pub use build_error::build_error;
62 /// Prefix to appear before log messages printed from within the `kernel` crate.
63 const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
65 /// The top level entrypoint to implementing a kernel module.
67 /// For any teardown or cleanup operations, your type may implement [`Drop`].
68 pub trait Module: Sized + Sync + Send {
69 /// Called at module initialization time.
71 /// Use this method to perform whatever setup or registration your module
74 /// Equivalent to the `module_init` macro in the C API.
75 fn init(module: &'static ThisModule) -> error::Result<Self>;
78 /// Equivalent to `THIS_MODULE` in the C API.
80 /// C header: [`include/linux/export.h`](srctree/include/linux/export.h)
81 pub struct ThisModule(*mut bindings::module);
83 // SAFETY: `THIS_MODULE` may be used from all threads within a module.
84 unsafe impl Sync for ThisModule {}
87 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
91 /// The pointer must be equal to the right `THIS_MODULE`.
92 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
97 #[cfg(not(any(testlib, test)))]
99 fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
100 pr_emerg!("{}\n", info);
102 unsafe { bindings::BUG() };
105 /// Produces a pointer to an object from a pointer to one of its fields.
109 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in
110 /// bounds of the same allocation.
115 /// # use kernel::container_of;
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));
129 macro_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