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(generic_nonzero)] 21 #![feature(inline_const)] 22 #![feature(pointer_is_aligned)] 23 // 24 // Stable since Rust 1.81.0. 25 #![feature(lint_reasons)] 26 // 27 // Stable since Rust 1.82.0. 28 #![feature(raw_ref_op)] 29 // 30 // Stable since Rust 1.83.0. 31 #![feature(const_maybe_uninit_as_mut_ptr)] 32 #![feature(const_mut_refs)] 33 #![feature(const_option)] 34 #![feature(const_ptr_write)] 35 #![feature(const_refs_to_cell)] 36 // 37 // Expected to become stable. 38 #![feature(arbitrary_self_types)] 39 // 40 // To be determined. 41 #![feature(used_with_arg)] 42 // 43 // `feature(derive_coerce_pointee)` is expected to become stable. Before Rust 44 // 1.84.0, it did not exist, so enable the predecessor features. 45 #![cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, feature(derive_coerce_pointee))] 46 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(coerce_unsized))] 47 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(dispatch_from_dyn))] 48 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(unsize))] 49 // 50 // `feature(file_with_nul)` is expected to become stable. Before Rust 1.89.0, it did not exist, so 51 // enable it conditionally. 52 #![cfg_attr(CONFIG_RUSTC_HAS_FILE_WITH_NUL, feature(file_with_nul))] 53 54 // Ensure conditional compilation based on the kernel configuration works; 55 // otherwise we may silently break things like initcall handling. 56 #[cfg(not(CONFIG_RUST))] 57 compile_error!("Missing kernel configuration for conditional compilation"); 58 59 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate). 60 extern crate self as kernel; 61 62 pub use ffi; 63 64 pub mod acpi; 65 pub mod alloc; 66 #[cfg(CONFIG_AUXILIARY_BUS)] 67 pub mod auxiliary; 68 pub mod bitmap; 69 pub mod bits; 70 #[cfg(CONFIG_BLOCK)] 71 pub mod block; 72 pub mod bug; 73 #[doc(hidden)] 74 pub mod build_assert; 75 pub mod clk; 76 #[cfg(CONFIG_CONFIGFS_FS)] 77 pub mod configfs; 78 pub mod cpu; 79 #[cfg(CONFIG_CPU_FREQ)] 80 pub mod cpufreq; 81 pub mod cpumask; 82 pub mod cred; 83 pub mod debugfs; 84 pub mod device; 85 pub mod device_id; 86 pub mod devres; 87 pub mod dma; 88 pub mod driver; 89 #[cfg(CONFIG_DRM = "y")] 90 pub mod drm; 91 pub mod error; 92 pub mod faux; 93 #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] 94 pub mod firmware; 95 pub mod fmt; 96 pub mod fs; 97 pub mod id_pool; 98 pub mod init; 99 pub mod io; 100 pub mod ioctl; 101 pub mod iov; 102 pub mod irq; 103 pub mod jump_label; 104 #[cfg(CONFIG_KUNIT)] 105 pub mod kunit; 106 pub mod list; 107 pub mod maple_tree; 108 pub mod miscdevice; 109 pub mod mm; 110 #[cfg(CONFIG_NET)] 111 pub mod net; 112 pub mod of; 113 #[cfg(CONFIG_PM_OPP)] 114 pub mod opp; 115 pub mod page; 116 #[cfg(CONFIG_PCI)] 117 pub mod pci; 118 pub mod pid_namespace; 119 pub mod platform; 120 pub mod prelude; 121 pub mod print; 122 pub mod processor; 123 pub mod ptr; 124 pub mod rbtree; 125 pub mod regulator; 126 pub mod revocable; 127 pub mod scatterlist; 128 pub mod security; 129 pub mod seq_file; 130 pub mod sizes; 131 mod static_assert; 132 #[doc(hidden)] 133 pub mod std_vendor; 134 pub mod str; 135 pub mod sync; 136 pub mod task; 137 pub mod time; 138 pub mod tracepoint; 139 pub mod transmute; 140 pub mod types; 141 pub mod uaccess; 142 pub mod workqueue; 143 pub mod xarray; 144 145 #[doc(hidden)] 146 pub use bindings; 147 pub use macros; 148 pub use uapi; 149 150 /// Prefix to appear before log messages printed from within the `kernel` crate. 151 const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; 152 153 /// The top level entrypoint to implementing a kernel module. 154 /// 155 /// For any teardown or cleanup operations, your type may implement [`Drop`]. 156 pub trait Module: Sized + Sync + Send { 157 /// Called at module initialization time. 158 /// 159 /// Use this method to perform whatever setup or registration your module 160 /// should do. 161 /// 162 /// Equivalent to the `module_init` macro in the C API. 163 fn init(module: &'static ThisModule) -> error::Result<Self>; 164 } 165 166 /// A module that is pinned and initialised in-place. 167 pub trait InPlaceModule: Sync + Send { 168 /// Creates an initialiser for the module. 169 /// 170 /// It is called when the module is loaded. 171 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error>; 172 } 173 174 impl<T: Module> InPlaceModule for T { 175 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error> { 176 let initer = move |slot: *mut Self| { 177 let m = <Self as Module>::init(module)?; 178 179 // SAFETY: `slot` is valid for write per the contract with `pin_init_from_closure`. 180 unsafe { slot.write(m) }; 181 Ok(()) 182 }; 183 184 // SAFETY: On success, `initer` always fully initialises an instance of `Self`. 185 unsafe { pin_init::pin_init_from_closure(initer) } 186 } 187 } 188 189 /// Metadata attached to a [`Module`] or [`InPlaceModule`]. 190 pub trait ModuleMetadata { 191 /// The name of the module as specified in the `module!` macro. 192 const NAME: &'static crate::str::CStr; 193 } 194 195 /// Equivalent to `THIS_MODULE` in the C API. 196 /// 197 /// C header: [`include/linux/init.h`](srctree/include/linux/init.h) 198 pub struct ThisModule(*mut bindings::module); 199 200 // SAFETY: `THIS_MODULE` may be used from all threads within a module. 201 unsafe impl Sync for ThisModule {} 202 203 impl ThisModule { 204 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer. 205 /// 206 /// # Safety 207 /// 208 /// The pointer must be equal to the right `THIS_MODULE`. 209 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule { 210 ThisModule(ptr) 211 } 212 213 /// Access the raw pointer for this module. 214 /// 215 /// It is up to the user to use it correctly. 216 pub const fn as_ptr(&self) -> *mut bindings::module { 217 self.0 218 } 219 } 220 221 #[cfg(not(testlib))] 222 #[panic_handler] 223 fn panic(info: &core::panic::PanicInfo<'_>) -> ! { 224 pr_emerg!("{}\n", info); 225 // SAFETY: FFI call. 226 unsafe { bindings::BUG() }; 227 } 228 229 /// Produces a pointer to an object from a pointer to one of its fields. 230 /// 231 /// If you encounter a type mismatch due to the [`Opaque`] type, then use [`Opaque::cast_into`] or 232 /// [`Opaque::cast_from`] to resolve the mismatch. 233 /// 234 /// [`Opaque`]: crate::types::Opaque 235 /// [`Opaque::cast_into`]: crate::types::Opaque::cast_into 236 /// [`Opaque::cast_from`]: crate::types::Opaque::cast_from 237 /// 238 /// # Safety 239 /// 240 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in 241 /// bounds of the same allocation. 242 /// 243 /// # Examples 244 /// 245 /// ``` 246 /// # use kernel::container_of; 247 /// struct Test { 248 /// a: u64, 249 /// b: u32, 250 /// } 251 /// 252 /// let test = Test { a: 10, b: 20 }; 253 /// let b_ptr: *const _ = &test.b; 254 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be 255 /// // in-bounds of the same allocation as `b_ptr`. 256 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) }; 257 /// assert!(core::ptr::eq(&test, test_alias)); 258 /// ``` 259 #[macro_export] 260 macro_rules! container_of { 261 ($field_ptr:expr, $Container:ty, $($fields:tt)*) => {{ 262 let offset: usize = ::core::mem::offset_of!($Container, $($fields)*); 263 let field_ptr = $field_ptr; 264 let container_ptr = field_ptr.byte_sub(offset).cast::<$Container>(); 265 $crate::assert_same_type(field_ptr, (&raw const (*container_ptr).$($fields)*).cast_mut()); 266 container_ptr 267 }} 268 } 269 270 /// Helper for [`container_of!`]. 271 #[doc(hidden)] 272 pub fn assert_same_type<T>(_: T, _: T) {} 273 274 /// Helper for `.rs.S` files. 275 #[doc(hidden)] 276 #[macro_export] 277 macro_rules! concat_literals { 278 ($( $asm:literal )* ) => { 279 ::core::concat!($($asm),*) 280 }; 281 } 282 283 /// Wrapper around `asm!` configured for use in the kernel. 284 /// 285 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 286 /// syntax. 287 // For x86, `asm!` uses intel syntax by default, but we want to use at&t syntax in the kernel. 288 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] 289 #[macro_export] 290 macro_rules! asm { 291 ($($asm:expr),* ; $($rest:tt)*) => { 292 ::core::arch::asm!( $($asm)*, options(att_syntax), $($rest)* ) 293 }; 294 } 295 296 /// Wrapper around `asm!` configured for use in the kernel. 297 /// 298 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 299 /// syntax. 300 // For non-x86 arches we just pass through to `asm!`. 301 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))] 302 #[macro_export] 303 macro_rules! asm { 304 ($($asm:expr),* ; $($rest:tt)*) => { 305 ::core::arch::asm!( $($asm)*, $($rest)* ) 306 }; 307 } 308 309 /// Gets the C string file name of a [`Location`]. 310 /// 311 /// If `Location::file_as_c_str()` is not available, returns a string that warns about it. 312 /// 313 /// [`Location`]: core::panic::Location 314 /// 315 /// # Examples 316 /// 317 /// ``` 318 /// # use kernel::file_from_location; 319 /// 320 /// #[track_caller] 321 /// fn foo() { 322 /// let caller = core::panic::Location::caller(); 323 /// 324 /// // Output: 325 /// // - A path like "rust/kernel/example.rs" if `file_as_c_str()` is available. 326 /// // - "<Location::file_as_c_str() not supported>" otherwise. 327 /// let caller_file = file_from_location(caller); 328 /// 329 /// // Prints out the message with caller's file name. 330 /// pr_info!("foo() called in file {caller_file:?}\n"); 331 /// 332 /// # if cfg!(CONFIG_RUSTC_HAS_FILE_WITH_NUL) { 333 /// # assert_eq!(Ok(caller.file()), caller_file.to_str()); 334 /// # } 335 /// } 336 /// 337 /// # foo(); 338 /// ``` 339 #[inline] 340 pub fn file_from_location<'a>(loc: &'a core::panic::Location<'a>) -> &'a core::ffi::CStr { 341 #[cfg(CONFIG_RUSTC_HAS_FILE_AS_C_STR)] 342 { 343 loc.file_as_c_str() 344 } 345 346 #[cfg(all(CONFIG_RUSTC_HAS_FILE_WITH_NUL, not(CONFIG_RUSTC_HAS_FILE_AS_C_STR)))] 347 { 348 loc.file_with_nul() 349 } 350 351 #[cfg(not(CONFIG_RUSTC_HAS_FILE_WITH_NUL))] 352 { 353 let _ = loc; 354 c"<Location::file_as_c_str() not supported>" 355 } 356 } 357