xref: /openbmc/linux/rust/kernel/lib.rs (revision a9886aad)
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(dispatch_from_dyn)]
18 #![feature(new_uninit)]
19 #![feature(receiver_trait)]
20 #![feature(unsize)]
21 
22 // Ensure conditional compilation based on the kernel configuration works;
23 // otherwise we may silently break things like initcall handling.
24 #[cfg(not(CONFIG_RUST))]
25 compile_error!("Missing kernel configuration for conditional compilation");
26 
27 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate).
28 extern crate self as kernel;
29 
30 #[cfg(not(test))]
31 #[cfg(not(testlib))]
32 mod allocator;
33 mod build_assert;
34 pub mod error;
35 pub mod init;
36 pub mod ioctl;
37 #[cfg(CONFIG_KUNIT)]
38 pub mod kunit;
39 pub mod prelude;
40 pub mod print;
41 mod static_assert;
42 #[doc(hidden)]
43 pub mod std_vendor;
44 pub mod str;
45 pub mod sync;
46 pub mod task;
47 pub mod types;
48 
49 #[doc(hidden)]
50 pub use bindings;
51 pub use macros;
52 pub use uapi;
53 
54 #[doc(hidden)]
55 pub use build_error::build_error;
56 
57 /// Prefix to appear before log messages printed from within the `kernel` crate.
58 const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
59 
60 /// The top level entrypoint to implementing a kernel module.
61 ///
62 /// For any teardown or cleanup operations, your type may implement [`Drop`].
63 pub trait Module: Sized + Sync + Send {
64     /// Called at module initialization time.
65     ///
66     /// Use this method to perform whatever setup or registration your module
67     /// should do.
68     ///
69     /// Equivalent to the `module_init` macro in the C API.
70     fn init(module: &'static ThisModule) -> error::Result<Self>;
71 }
72 
73 /// Equivalent to `THIS_MODULE` in the C API.
74 ///
75 /// C header: `include/linux/export.h`
76 pub struct ThisModule(*mut bindings::module);
77 
78 // SAFETY: `THIS_MODULE` may be used from all threads within a module.
79 unsafe impl Sync for ThisModule {}
80 
81 impl ThisModule {
82     /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
83     ///
84     /// # Safety
85     ///
86     /// The pointer must be equal to the right `THIS_MODULE`.
87     pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
88         ThisModule(ptr)
89     }
90 }
91 
92 #[cfg(not(any(testlib, test)))]
93 #[panic_handler]
94 fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
95     pr_emerg!("{}\n", info);
96     // SAFETY: FFI call.
97     unsafe { bindings::BUG() };
98 }
99