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(allocator_api)]
16 #![feature(coerce_unsized)]
17 #![feature(core_ffi_c)]
18 #![feature(dispatch_from_dyn)]
19 #![feature(generic_associated_types)]
20 #![feature(receiver_trait)]
21 #![feature(unsize)]
22 
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");
27 
28 #[cfg(not(test))]
29 #[cfg(not(testlib))]
30 mod allocator;
31 mod build_assert;
32 pub mod error;
33 pub mod prelude;
34 pub mod print;
35 mod static_assert;
36 #[doc(hidden)]
37 pub mod std_vendor;
38 pub mod str;
39 pub mod sync;
40 pub mod types;
41 
42 #[doc(hidden)]
43 pub use bindings;
44 pub use macros;
45 
46 #[doc(hidden)]
47 pub use build_error::build_error;
48 
49 /// Prefix to appear before log messages printed from within the `kernel` crate.
50 const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
51 
52 /// The top level entrypoint to implementing a kernel module.
53 ///
54 /// For any teardown or cleanup operations, your type may implement [`Drop`].
55 pub trait Module: Sized + Sync {
56     /// Called at module initialization time.
57     ///
58     /// Use this method to perform whatever setup or registration your module
59     /// should do.
60     ///
61     /// Equivalent to the `module_init` macro in the C API.
init(module: &'static ThisModule) -> error::Result<Self>62     fn init(module: &'static ThisModule) -> error::Result<Self>;
63 }
64 
65 /// Equivalent to `THIS_MODULE` in the C API.
66 ///
67 /// C header: `include/linux/export.h`
68 pub struct ThisModule(*mut bindings::module);
69 
70 // SAFETY: `THIS_MODULE` may be used from all threads within a module.
71 unsafe impl Sync for ThisModule {}
72 
73 impl ThisModule {
74     /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
75     ///
76     /// # Safety
77     ///
78     /// The pointer must be equal to the right `THIS_MODULE`.
from_ptr(ptr: *mut bindings::module) -> ThisModule79     pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
80         ThisModule(ptr)
81     }
82 }
83 
84 #[cfg(not(any(testlib, test)))]
85 #[panic_handler]
panic(info: &core::panic::PanicInfo<'_>) -> !86 fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
87     pr_emerg!("{}\n", info);
88     // SAFETY: FFI call.
89     unsafe { bindings::BUG() };
90     // Bindgen currently does not recognize `__noreturn` so `BUG` returns `()`
91     // instead of `!`. See <https://github.com/rust-lang/rust-bindgen/issues/2094>.
92     loop {}
93 }
94