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`] 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 // 16 // Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on 17 // the unstable features in use. 18 // 19 // Stable since Rust 1.79.0. 20 #![feature(inline_const)] 21 // 22 // Stable since Rust 1.81.0. 23 #![feature(lint_reasons)] 24 // 25 // Stable since Rust 1.82.0. 26 #![feature(raw_ref_op)] 27 // 28 // Stable since Rust 1.83.0. 29 #![feature(const_maybe_uninit_as_mut_ptr)] 30 #![feature(const_mut_refs)] 31 #![feature(const_ptr_write)] 32 #![feature(const_refs_to_cell)] 33 // 34 // Expected to become stable. 35 #![feature(arbitrary_self_types)] 36 // 37 // `feature(derive_coerce_pointee)` is expected to become stable. Before Rust 38 // 1.84.0, it did not exist, so enable the predecessor features. 39 #![cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, feature(derive_coerce_pointee))] 40 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(coerce_unsized))] 41 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(dispatch_from_dyn))] 42 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(unsize))] 43 44 // Ensure conditional compilation based on the kernel configuration works; 45 // otherwise we may silently break things like initcall handling. 46 #[cfg(not(CONFIG_RUST))] 47 compile_error!("Missing kernel configuration for conditional compilation"); 48 49 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate). 50 extern crate self as kernel; 51 52 pub use ffi; 53 54 pub mod alloc; 55 #[cfg(CONFIG_BLOCK)] 56 pub mod block; 57 #[doc(hidden)] 58 pub mod build_assert; 59 pub mod cred; 60 pub mod device; 61 pub mod device_id; 62 pub mod devres; 63 pub mod dma; 64 pub mod driver; 65 pub mod error; 66 pub mod faux; 67 #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] 68 pub mod firmware; 69 pub mod fs; 70 pub mod init; 71 pub mod io; 72 pub mod ioctl; 73 pub mod jump_label; 74 #[cfg(CONFIG_KUNIT)] 75 pub mod kunit; 76 pub mod list; 77 pub mod miscdevice; 78 #[cfg(CONFIG_NET)] 79 pub mod net; 80 pub mod of; 81 pub mod page; 82 #[cfg(CONFIG_PCI)] 83 pub mod pci; 84 pub mod pid_namespace; 85 pub mod platform; 86 pub mod prelude; 87 pub mod print; 88 pub mod rbtree; 89 pub mod revocable; 90 pub mod security; 91 pub mod seq_file; 92 pub mod sizes; 93 mod static_assert; 94 #[doc(hidden)] 95 pub mod std_vendor; 96 pub mod str; 97 pub mod sync; 98 pub mod task; 99 pub mod time; 100 pub mod tracepoint; 101 pub mod transmute; 102 pub mod types; 103 pub mod uaccess; 104 pub mod workqueue; 105 pub mod xarray; 106 107 #[doc(hidden)] 108 pub use bindings; 109 pub use macros; 110 pub use uapi; 111 112 /// Prefix to appear before log messages printed from within the `kernel` crate. 113 const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; 114 115 /// The top level entrypoint to implementing a kernel module. 116 /// 117 /// For any teardown or cleanup operations, your type may implement [`Drop`]. 118 pub trait Module: Sized + Sync + Send { 119 /// Called at module initialization time. 120 /// 121 /// Use this method to perform whatever setup or registration your module 122 /// should do. 123 /// 124 /// Equivalent to the `module_init` macro in the C API. 125 fn init(module: &'static ThisModule) -> error::Result<Self>; 126 } 127 128 /// A module that is pinned and initialised in-place. 129 pub trait InPlaceModule: Sync + Send { 130 /// Creates an initialiser for the module. 131 /// 132 /// It is called when the module is loaded. 133 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error>; 134 } 135 136 impl<T: Module> InPlaceModule for T { 137 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error> { 138 let initer = move |slot: *mut Self| { 139 let m = <Self as Module>::init(module)?; 140 141 // SAFETY: `slot` is valid for write per the contract with `pin_init_from_closure`. 142 unsafe { slot.write(m) }; 143 Ok(()) 144 }; 145 146 // SAFETY: On success, `initer` always fully initialises an instance of `Self`. 147 unsafe { pin_init::pin_init_from_closure(initer) } 148 } 149 } 150 151 /// Metadata attached to a [`Module`] or [`InPlaceModule`]. 152 pub trait ModuleMetadata { 153 /// The name of the module as specified in the `module!` macro. 154 const NAME: &'static crate::str::CStr; 155 } 156 157 /// Equivalent to `THIS_MODULE` in the C API. 158 /// 159 /// C header: [`include/linux/init.h`](srctree/include/linux/init.h) 160 pub struct ThisModule(*mut bindings::module); 161 162 // SAFETY: `THIS_MODULE` may be used from all threads within a module. 163 unsafe impl Sync for ThisModule {} 164 165 impl ThisModule { 166 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer. 167 /// 168 /// # Safety 169 /// 170 /// The pointer must be equal to the right `THIS_MODULE`. 171 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule { 172 ThisModule(ptr) 173 } 174 175 /// Access the raw pointer for this module. 176 /// 177 /// It is up to the user to use it correctly. 178 pub const fn as_ptr(&self) -> *mut bindings::module { 179 self.0 180 } 181 } 182 183 #[cfg(not(any(testlib, test)))] 184 #[panic_handler] 185 fn panic(info: &core::panic::PanicInfo<'_>) -> ! { 186 pr_emerg!("{}\n", info); 187 // SAFETY: FFI call. 188 unsafe { bindings::BUG() }; 189 } 190 191 /// Produces a pointer to an object from a pointer to one of its fields. 192 /// 193 /// # Safety 194 /// 195 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in 196 /// bounds of the same allocation. 197 /// 198 /// # Examples 199 /// 200 /// ``` 201 /// # use kernel::container_of; 202 /// struct Test { 203 /// a: u64, 204 /// b: u32, 205 /// } 206 /// 207 /// let test = Test { a: 10, b: 20 }; 208 /// let b_ptr = &test.b; 209 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be 210 /// // in-bounds of the same allocation as `b_ptr`. 211 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) }; 212 /// assert!(core::ptr::eq(&test, test_alias)); 213 /// ``` 214 #[macro_export] 215 macro_rules! container_of { 216 ($ptr:expr, $type:ty, $($f:tt)*) => {{ 217 let ptr = $ptr as *const _ as *const u8; 218 let offset: usize = ::core::mem::offset_of!($type, $($f)*); 219 ptr.sub(offset) as *const $type 220 }} 221 } 222 223 /// Helper for `.rs.S` files. 224 #[doc(hidden)] 225 #[macro_export] 226 macro_rules! concat_literals { 227 ($( $asm:literal )* ) => { 228 ::core::concat!($($asm),*) 229 }; 230 } 231 232 /// Wrapper around `asm!` configured for use in the kernel. 233 /// 234 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 235 /// syntax. 236 // For x86, `asm!` uses intel syntax by default, but we want to use at&t syntax in the kernel. 237 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] 238 #[macro_export] 239 macro_rules! asm { 240 ($($asm:expr),* ; $($rest:tt)*) => { 241 ::core::arch::asm!( $($asm)*, options(att_syntax), $($rest)* ) 242 }; 243 } 244 245 /// Wrapper around `asm!` configured for use in the kernel. 246 /// 247 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 248 /// syntax. 249 // For non-x86 arches we just pass through to `asm!`. 250 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))] 251 #[macro_export] 252 macro_rules! asm { 253 ($($asm:expr),* ; $($rest:tt)*) => { 254 ::core::arch::asm!( $($asm)*, $($rest)* ) 255 }; 256 } 257