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 device; 32 pub mod error; 33 pub mod init; 34 pub mod ioctl; 35 #[cfg(CONFIG_KUNIT)] 36 pub mod kunit; 37 #[cfg(CONFIG_NET)] 38 pub mod net; 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 time; 48 pub mod types; 49 pub mod workqueue; 50 51 #[doc(hidden)] 52 pub use bindings; 53 pub use macros; 54 pub use uapi; 55 56 #[doc(hidden)] 57 pub use build_error::build_error; 58 59 /// Prefix to appear before log messages printed from within the `kernel` crate. 60 const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; 61 62 /// The top level entrypoint to implementing a kernel module. 63 /// 64 /// For any teardown or cleanup operations, your type may implement [`Drop`]. 65 pub trait Module: Sized + Sync + Send { 66 /// Called at module initialization time. 67 /// 68 /// Use this method to perform whatever setup or registration your module 69 /// should do. 70 /// 71 /// Equivalent to the `module_init` macro in the C API. 72 fn init(module: &'static ThisModule) -> error::Result<Self>; 73 } 74 75 /// Equivalent to `THIS_MODULE` in the C API. 76 /// 77 /// C header: [`include/linux/export.h`](srctree/include/linux/export.h) 78 pub struct ThisModule(*mut bindings::module); 79 80 // SAFETY: `THIS_MODULE` may be used from all threads within a module. 81 unsafe impl Sync for ThisModule {} 82 83 impl ThisModule { 84 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer. 85 /// 86 /// # Safety 87 /// 88 /// The pointer must be equal to the right `THIS_MODULE`. 89 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule { 90 ThisModule(ptr) 91 } 92 93 /// Access the raw pointer for this module. 94 /// 95 /// It is up to the user to use it correctly. 96 pub const fn as_ptr(&self) -> *mut bindings::module { 97 self.0 98 } 99 } 100 101 #[cfg(not(any(testlib, test)))] 102 #[panic_handler] 103 fn panic(info: &core::panic::PanicInfo<'_>) -> ! { 104 pr_emerg!("{}\n", info); 105 // SAFETY: FFI call. 106 unsafe { bindings::BUG() }; 107 } 108 109 /// Produces a pointer to an object from a pointer to one of its fields. 110 /// 111 /// # Safety 112 /// 113 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in 114 /// bounds of the same allocation. 115 /// 116 /// # Examples 117 /// 118 /// ``` 119 /// # use kernel::container_of; 120 /// struct Test { 121 /// a: u64, 122 /// b: u32, 123 /// } 124 /// 125 /// let test = Test { a: 10, b: 20 }; 126 /// let b_ptr = &test.b; 127 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be 128 /// // in-bounds of the same allocation as `b_ptr`. 129 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) }; 130 /// assert!(core::ptr::eq(&test, test_alias)); 131 /// ``` 132 #[macro_export] 133 macro_rules! container_of { 134 ($ptr:expr, $type:ty, $($f:tt)*) => {{ 135 let ptr = $ptr as *const _ as *const u8; 136 let offset: usize = ::core::mem::offset_of!($type, $($f)*); 137 ptr.sub(offset) as *const $type 138 }} 139 } 140