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`] 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 //
16 // Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on
17 // the unstable features in use.
18 //
19 // Stable since Rust 1.79.0.
20 #![feature(inline_const)]
21 //
22 // Stable since Rust 1.81.0.
23 #![feature(lint_reasons)]
24 //
25 // Stable since Rust 1.82.0.
26 #![feature(raw_ref_op)]
27 //
28 // Stable since Rust 1.83.0.
29 #![feature(const_maybe_uninit_as_mut_ptr)]
30 #![feature(const_mut_refs)]
31 #![feature(const_ptr_write)]
32 #![feature(const_refs_to_cell)]
33 //
34 // Expected to become stable.
35 #![feature(arbitrary_self_types)]
36 //
37 // `feature(derive_coerce_pointee)` is expected to become stable. Before Rust
38 // 1.84.0, it did not exist, so enable the predecessor features.
39 #![cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, feature(derive_coerce_pointee))]
40 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(coerce_unsized))]
41 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(dispatch_from_dyn))]
42 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(unsize))]
43
44 // Ensure conditional compilation based on the kernel configuration works;
45 // otherwise we may silently break things like initcall handling.
46 #[cfg(not(CONFIG_RUST))]
47 compile_error!("Missing kernel configuration for conditional compilation");
48
49 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate).
50 extern crate self as kernel;
51
52 pub use ffi;
53
54 pub mod alloc;
55 #[cfg(CONFIG_AUXILIARY_BUS)]
56 pub mod auxiliary;
57 #[cfg(CONFIG_BLOCK)]
58 pub mod block;
59 #[doc(hidden)]
60 pub mod build_assert;
61 pub mod clk;
62 #[cfg(CONFIG_CONFIGFS_FS)]
63 pub mod configfs;
64 pub mod cpu;
65 #[cfg(CONFIG_CPU_FREQ)]
66 pub mod cpufreq;
67 pub mod cpumask;
68 pub mod cred;
69 pub mod device;
70 pub mod device_id;
71 pub mod devres;
72 pub mod dma;
73 pub mod driver;
74 #[cfg(CONFIG_DRM = "y")]
75 pub mod drm;
76 pub mod error;
77 pub mod faux;
78 #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)]
79 pub mod firmware;
80 pub mod fs;
81 pub mod init;
82 pub mod io;
83 pub mod ioctl;
84 pub mod jump_label;
85 #[cfg(CONFIG_KUNIT)]
86 pub mod kunit;
87 pub mod list;
88 pub mod miscdevice;
89 pub mod mm;
90 #[cfg(CONFIG_NET)]
91 pub mod net;
92 pub mod of;
93 #[cfg(CONFIG_PM_OPP)]
94 pub mod opp;
95 pub mod page;
96 #[cfg(CONFIG_PCI)]
97 pub mod pci;
98 pub mod pid_namespace;
99 pub mod platform;
100 pub mod prelude;
101 pub mod print;
102 pub mod rbtree;
103 pub mod revocable;
104 pub mod security;
105 pub mod seq_file;
106 pub mod sizes;
107 mod static_assert;
108 #[doc(hidden)]
109 pub mod std_vendor;
110 pub mod str;
111 pub mod sync;
112 pub mod task;
113 pub mod time;
114 pub mod tracepoint;
115 pub mod transmute;
116 pub mod types;
117 pub mod uaccess;
118 pub mod workqueue;
119 pub mod xarray;
120
121 #[doc(hidden)]
122 pub use bindings;
123 pub use macros;
124 pub use uapi;
125
126 /// Prefix to appear before log messages printed from within the `kernel` crate.
127 const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
128
129 /// The top level entrypoint to implementing a kernel module.
130 ///
131 /// For any teardown or cleanup operations, your type may implement [`Drop`].
132 pub trait Module: Sized + Sync + Send {
133 /// Called at module initialization time.
134 ///
135 /// Use this method to perform whatever setup or registration your module
136 /// should do.
137 ///
138 /// Equivalent to the `module_init` macro in the C API.
init(module: &'static ThisModule) -> error::Result<Self>139 fn init(module: &'static ThisModule) -> error::Result<Self>;
140 }
141
142 /// A module that is pinned and initialised in-place.
143 pub trait InPlaceModule: Sync + Send {
144 /// Creates an initialiser for the module.
145 ///
146 /// It is called when the module is loaded.
init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error>147 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error>;
148 }
149
150 impl<T: Module> InPlaceModule for T {
init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error>151 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error> {
152 let initer = move |slot: *mut Self| {
153 let m = <Self as Module>::init(module)?;
154
155 // SAFETY: `slot` is valid for write per the contract with `pin_init_from_closure`.
156 unsafe { slot.write(m) };
157 Ok(())
158 };
159
160 // SAFETY: On success, `initer` always fully initialises an instance of `Self`.
161 unsafe { pin_init::pin_init_from_closure(initer) }
162 }
163 }
164
165 /// Metadata attached to a [`Module`] or [`InPlaceModule`].
166 pub trait ModuleMetadata {
167 /// The name of the module as specified in the `module!` macro.
168 const NAME: &'static crate::str::CStr;
169 }
170
171 /// Equivalent to `THIS_MODULE` in the C API.
172 ///
173 /// C header: [`include/linux/init.h`](srctree/include/linux/init.h)
174 pub struct ThisModule(*mut bindings::module);
175
176 // SAFETY: `THIS_MODULE` may be used from all threads within a module.
177 unsafe impl Sync for ThisModule {}
178
179 impl ThisModule {
180 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
181 ///
182 /// # Safety
183 ///
184 /// The pointer must be equal to the right `THIS_MODULE`.
from_ptr(ptr: *mut bindings::module) -> ThisModule185 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
186 ThisModule(ptr)
187 }
188
189 /// Access the raw pointer for this module.
190 ///
191 /// It is up to the user to use it correctly.
as_ptr(&self) -> *mut bindings::module192 pub const fn as_ptr(&self) -> *mut bindings::module {
193 self.0
194 }
195 }
196
197 #[cfg(not(any(testlib, test)))]
198 #[panic_handler]
panic(info: &core::panic::PanicInfo<'_>) -> !199 fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
200 pr_emerg!("{}\n", info);
201 // SAFETY: FFI call.
202 unsafe { bindings::BUG() };
203 }
204
205 /// Produces a pointer to an object from a pointer to one of its fields.
206 ///
207 /// # Safety
208 ///
209 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in
210 /// bounds of the same allocation.
211 ///
212 /// # Examples
213 ///
214 /// ```
215 /// # use kernel::container_of;
216 /// struct Test {
217 /// a: u64,
218 /// b: u32,
219 /// }
220 ///
221 /// let test = Test { a: 10, b: 20 };
222 /// let b_ptr: *const _ = &test.b;
223 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be
224 /// // in-bounds of the same allocation as `b_ptr`.
225 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) };
226 /// assert!(core::ptr::eq(&test, test_alias));
227 /// ```
228 #[macro_export]
229 macro_rules! container_of {
230 ($field_ptr:expr, $Container:ty, $($fields:tt)*) => {{
231 let offset: usize = ::core::mem::offset_of!($Container, $($fields)*);
232 let field_ptr = $field_ptr;
233 let container_ptr = field_ptr.byte_sub(offset).cast::<$Container>();
234 $crate::assert_same_type(field_ptr, (&raw const (*container_ptr).$($fields)*).cast_mut());
235 container_ptr
236 }}
237 }
238
239 /// Helper for [`container_of!`].
240 #[doc(hidden)]
assert_same_type<T>(_: T, _: T)241 pub fn assert_same_type<T>(_: T, _: T) {}
242
243 /// Helper for `.rs.S` files.
244 #[doc(hidden)]
245 #[macro_export]
246 macro_rules! concat_literals {
247 ($( $asm:literal )* ) => {
248 ::core::concat!($($asm),*)
249 };
250 }
251
252 /// Wrapper around `asm!` configured for use in the kernel.
253 ///
254 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!`
255 /// syntax.
256 // For x86, `asm!` uses intel syntax by default, but we want to use at&t syntax in the kernel.
257 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
258 #[macro_export]
259 macro_rules! asm {
260 ($($asm:expr),* ; $($rest:tt)*) => {
261 ::core::arch::asm!( $($asm)*, options(att_syntax), $($rest)* )
262 };
263 }
264
265 /// Wrapper around `asm!` configured for use in the kernel.
266 ///
267 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!`
268 /// syntax.
269 // For non-x86 arches we just pass through to `asm!`.
270 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
271 #[macro_export]
272 macro_rules! asm {
273 ($($asm:expr),* ; $($rest:tt)*) => {
274 ::core::arch::asm!( $($asm)*, $($rest)* )
275 };
276 }
277