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))]
24 compile_error!("Missing kernel configuration for conditional compilation");
25
26 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate).
27 extern crate self as kernel;
28
29 pub mod alloc;
30 #[cfg(CONFIG_BLOCK)]
31 pub mod block;
32 mod build_assert;
33 pub mod device;
34 pub mod error;
35 #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)]
36 pub mod firmware;
37 pub mod init;
38 pub mod ioctl;
39 #[cfg(CONFIG_KUNIT)]
40 pub mod kunit;
41 pub mod list;
42 #[cfg(CONFIG_NET)]
43 pub mod net;
44 pub mod page;
45 pub mod prelude;
46 pub mod print;
47 pub mod rbtree;
48 pub mod sizes;
49 mod static_assert;
50 #[doc(hidden)]
51 pub mod std_vendor;
52 pub mod str;
53 pub mod sync;
54 pub mod task;
55 pub mod time;
56 pub mod types;
57 pub mod uaccess;
58 pub mod workqueue;
59
60 #[doc(hidden)]
61 pub use bindings;
62 pub use macros;
63 pub use uapi;
64
65 #[doc(hidden)]
66 pub use build_error::build_error;
67
68 /// Prefix to appear before log messages printed from within the `kernel` crate.
69 const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
70
71 /// The top level entrypoint to implementing a kernel module.
72 ///
73 /// For any teardown or cleanup operations, your type may implement [`Drop`].
74 pub trait Module: Sized + Sync + Send {
75 /// Called at module initialization time.
76 ///
77 /// Use this method to perform whatever setup or registration your module
78 /// should do.
79 ///
80 /// Equivalent to the `module_init` macro in the C API.
81 fn init(module: &'static ThisModule) -> error::Result<Self>;
82 }
83
84 /// Equivalent to `THIS_MODULE` in the C API.
85 ///
86 /// C header: [`include/linux/export.h`](srctree/include/linux/export.h)
87 pub struct ThisModule(*mut bindings::module);
88
89 // SAFETY: `THIS_MODULE` may be used from all threads within a module.
90 unsafe impl Sync for ThisModule {}
91
92 impl ThisModule {
93 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
94 ///
95 /// # Safety
96 ///
97 /// The pointer must be equal to the right `THIS_MODULE`.
98 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
99 ThisModule(ptr)
100 }
101
102 /// Access the raw pointer for this module.
103 ///
104 /// It is up to the user to use it correctly.
105 pub const fn as_ptr(&self) -> *mut bindings::module {
106 self.0
107 }
108 }
109
110 #[cfg(not(any(testlib, test)))]
111 #[panic_handler]
112 fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
113 pr_emerg!("{}\n", info);
114 // SAFETY: FFI call.
115 unsafe { bindings::BUG() };
116 }
117
118 /// Produces a pointer to an object from a pointer to one of its fields.
119 ///
120 /// # Safety
121 ///
122 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in
123 /// bounds of the same allocation.
124 ///
125 /// # Examples
126 ///
127 /// ```
128 /// # use kernel::container_of;
129 /// struct Test {
130 /// a: u64,
131 /// b: u32,
132 /// }
133 ///
134 /// let test = Test { a: 10, b: 20 };
135 /// let b_ptr = &test.b;
136 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be
137 /// // in-bounds of the same allocation as `b_ptr`.
138 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) };
139 /// assert!(core::ptr::eq(&test, test_alias));
140 /// ```
141 #[macro_export]
142 macro_rules! container_of {
143 ($ptr:expr, $type:ty, $($f:tt)*) => {{
144 let ptr = $ptr as *const _ as *const u8;
145 let offset: usize = ::core::mem::offset_of!($type, $($f)*);
146 ptr.sub(offset) as *const $type
147 }}
148 }
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