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