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(offset_of)] 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 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate). 29 extern crate self as kernel; 30 31 #[cfg(not(test))] 32 #[cfg(not(testlib))] 33 mod allocator; 34 mod build_assert; 35 pub mod error; 36 pub mod init; 37 pub mod ioctl; 38 #[cfg(CONFIG_KUNIT)] 39 pub mod kunit; 40 #[cfg(CONFIG_NET)] 41 pub mod net; 42 pub mod prelude; 43 pub mod print; 44 mod static_assert; 45 #[doc(hidden)] 46 pub mod std_vendor; 47 pub mod str; 48 pub mod sync; 49 pub mod task; 50 pub mod time; 51 pub mod types; 52 pub mod workqueue; 53 54 #[doc(hidden)] 55 pub use bindings; 56 pub use macros; 57 pub use uapi; 58 59 #[doc(hidden)] 60 pub use build_error::build_error; 61 62 /// Prefix to appear before log messages printed from within the `kernel` crate. 63 const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; 64 65 /// The top level entrypoint to implementing a kernel module. 66 /// 67 /// For any teardown or cleanup operations, your type may implement [`Drop`]. 68 pub trait Module: Sized + Sync { 69 /// Called at module initialization time. 70 /// 71 /// Use this method to perform whatever setup or registration your module 72 /// should do. 73 /// 74 /// Equivalent to the `module_init` macro in the C API. 75 fn init(module: &'static ThisModule) -> error::Result<Self>; 76 } 77 78 /// Equivalent to `THIS_MODULE` in the C API. 79 /// 80 /// C header: [`include/linux/export.h`](srctree/include/linux/export.h) 81 pub struct ThisModule(*mut bindings::module); 82 83 // SAFETY: `THIS_MODULE` may be used from all threads within a module. 84 unsafe impl Sync for ThisModule {} 85 86 impl ThisModule { 87 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer. 88 /// 89 /// # Safety 90 /// 91 /// The pointer must be equal to the right `THIS_MODULE`. 92 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule { 93 ThisModule(ptr) 94 } 95 } 96 97 #[cfg(not(any(testlib, test)))] 98 #[panic_handler] 99 fn panic(info: &core::panic::PanicInfo<'_>) -> ! { 100 pr_emerg!("{}\n", info); 101 // SAFETY: FFI call. 102 unsafe { bindings::BUG() }; 103 } 104 105 /// Produces a pointer to an object from a pointer to one of its fields. 106 /// 107 /// # Safety 108 /// 109 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in 110 /// bounds of the same allocation. 111 /// 112 /// # Examples 113 /// 114 /// ``` 115 /// # use kernel::container_of; 116 /// struct Test { 117 /// a: u64, 118 /// b: u32, 119 /// } 120 /// 121 /// let test = Test { a: 10, b: 20 }; 122 /// let b_ptr = &test.b; 123 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be 124 /// // in-bounds of the same allocation as `b_ptr`. 125 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) }; 126 /// assert!(core::ptr::eq(&test, test_alias)); 127 /// ``` 128 #[macro_export] 129 macro_rules! container_of { 130 ($ptr:expr, $type:ty, $($f:tt)*) => {{ 131 let ptr = $ptr as *const _ as *const u8; 132 let offset: usize = ::core::mem::offset_of!($type, $($f)*); 133 ptr.sub(offset) as *const $type 134 }} 135 } 136