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.
init(module: &'static ThisModule) -> error::Result<Self>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`.
from_ptr(ptr: *mut bindings::module) -> ThisModule98     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.
as_ptr(&self) -> *mut bindings::module105     pub const fn as_ptr(&self) -> *mut bindings::module {
106         self.0
107     }
108 }
109 
110 #[cfg(not(any(testlib, test)))]
111 #[panic_handler]
panic(info: &core::panic::PanicInfo<'_>) -> !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 }
149