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 #![feature(slice_ptr_len)] 24 // 25 // Stable since Rust 1.80.0. 26 #![feature(slice_flatten)] 27 // 28 // Stable since Rust 1.81.0. 29 #![feature(lint_reasons)] 30 // 31 // Stable since Rust 1.82.0. 32 #![feature(offset_of_nested)] 33 #![feature(raw_ref_op)] 34 // 35 // Stable since Rust 1.83.0. 36 #![feature(const_maybe_uninit_as_mut_ptr)] 37 #![feature(const_mut_refs)] 38 #![feature(const_option)] 39 #![feature(const_ptr_write)] 40 #![feature(const_refs_to_cell)] 41 // 42 // Stable since Rust 1.84.0. 43 #![feature(strict_provenance)] 44 // 45 // Stable since Rust 1.89.0. 46 #![feature(generic_arg_infer)] 47 // 48 // Expected to become stable. 49 #![feature(arbitrary_self_types)] 50 // 51 // To be determined. 52 #![feature(used_with_arg)] 53 // 54 // `feature(derive_coerce_pointee)` is expected to become stable. Before Rust 55 // 1.84.0, it did not exist, so enable the predecessor features. 56 #![cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, feature(derive_coerce_pointee))] 57 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(coerce_unsized))] 58 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(dispatch_from_dyn))] 59 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(unsize))] 60 // 61 // `feature(file_with_nul)` is expected to become stable. Before Rust 1.89.0, it did not exist, so 62 // enable it conditionally. 63 #![cfg_attr(CONFIG_RUSTC_HAS_FILE_WITH_NUL, feature(file_with_nul))] 64 65 // Ensure conditional compilation based on the kernel configuration works; 66 // otherwise we may silently break things like initcall handling. 67 #[cfg(not(CONFIG_RUST))] 68 compile_error!("Missing kernel configuration for conditional compilation"); 69 70 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate). 71 extern crate self as kernel; 72 73 pub use ffi; 74 75 pub mod acpi; 76 pub mod alloc; 77 #[cfg(CONFIG_AUXILIARY_BUS)] 78 pub mod auxiliary; 79 pub mod bitmap; 80 pub mod bits; 81 #[cfg(CONFIG_BLOCK)] 82 pub mod block; 83 pub mod bug; 84 #[doc(hidden)] 85 pub mod build_assert; 86 pub mod clk; 87 #[cfg(CONFIG_CONFIGFS_FS)] 88 pub mod configfs; 89 pub mod cpu; 90 #[cfg(CONFIG_CPU_FREQ)] 91 pub mod cpufreq; 92 pub mod cpumask; 93 pub mod cred; 94 pub mod debugfs; 95 pub mod device; 96 pub mod device_id; 97 pub mod devres; 98 pub mod dma; 99 pub mod driver; 100 #[cfg(CONFIG_DRM = "y")] 101 pub mod drm; 102 pub mod error; 103 pub mod faux; 104 #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] 105 pub mod firmware; 106 pub mod fmt; 107 pub mod fs; 108 #[cfg(CONFIG_GPU_BUDDY = "y")] 109 pub mod gpu; 110 #[cfg(CONFIG_I2C = "y")] 111 pub mod i2c; 112 pub mod id_pool; 113 #[doc(hidden)] 114 pub mod impl_flags; 115 pub mod init; 116 pub mod interop; 117 pub mod io; 118 pub mod ioctl; 119 pub mod iommu; 120 pub mod iov; 121 pub mod irq; 122 pub mod jump_label; 123 #[cfg(CONFIG_KUNIT)] 124 pub mod kunit; 125 pub mod list; 126 pub mod maple_tree; 127 pub mod miscdevice; 128 pub mod mm; 129 pub mod module_param; 130 #[cfg(CONFIG_NET)] 131 pub mod net; 132 pub mod num; 133 pub mod of; 134 #[cfg(CONFIG_PM_OPP)] 135 pub mod opp; 136 pub mod page; 137 #[cfg(CONFIG_PCI)] 138 pub mod pci; 139 pub mod pid_namespace; 140 pub mod platform; 141 pub mod prelude; 142 pub mod print; 143 pub mod processor; 144 pub mod ptr; 145 #[cfg(CONFIG_RUST_PWM_ABSTRACTIONS)] 146 pub mod pwm; 147 pub mod rbtree; 148 pub mod regulator; 149 pub mod revocable; 150 pub mod safety; 151 pub mod scatterlist; 152 pub mod security; 153 pub mod seq_file; 154 pub mod sizes; 155 pub mod slice; 156 #[cfg(CONFIG_SOC_BUS)] 157 pub mod soc; 158 mod static_assert; 159 #[doc(hidden)] 160 pub mod std_vendor; 161 pub mod str; 162 pub mod sync; 163 pub mod task; 164 pub mod time; 165 pub mod tracepoint; 166 pub mod transmute; 167 pub mod types; 168 pub mod uaccess; 169 #[cfg(CONFIG_USB = "y")] 170 pub mod usb; 171 pub mod workqueue; 172 pub mod xarray; 173 174 #[doc(hidden)] 175 pub use bindings; 176 pub use macros; 177 pub use uapi; 178 179 /// Prefix to appear before log messages printed from within the `kernel` crate. 180 const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; 181 182 /// The top level entrypoint to implementing a kernel module. 183 /// 184 /// For any teardown or cleanup operations, your type may implement [`Drop`]. 185 pub trait Module: Sized + Sync + Send { 186 /// Called at module initialization time. 187 /// 188 /// Use this method to perform whatever setup or registration your module 189 /// should do. 190 /// 191 /// Equivalent to the `module_init` macro in the C API. 192 fn init(module: &'static ThisModule) -> error::Result<Self>; 193 } 194 195 /// A module that is pinned and initialised in-place. 196 pub trait InPlaceModule: Sync + Send { 197 /// Creates an initialiser for the module. 198 /// 199 /// It is called when the module is loaded. 200 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error>; 201 } 202 203 impl<T: Module> InPlaceModule for T { 204 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error> { 205 let initer = move |slot: *mut Self| { 206 let m = <Self as Module>::init(module)?; 207 208 // SAFETY: `slot` is valid for write per the contract with `pin_init_from_closure`. 209 unsafe { slot.write(m) }; 210 Ok(()) 211 }; 212 213 // SAFETY: On success, `initer` always fully initialises an instance of `Self`. 214 unsafe { pin_init::pin_init_from_closure(initer) } 215 } 216 } 217 218 /// Metadata attached to a [`Module`] or [`InPlaceModule`]. 219 pub trait ModuleMetadata { 220 /// The name of the module as specified in the `module!` macro. 221 const NAME: &'static crate::str::CStr; 222 } 223 224 /// Equivalent to `THIS_MODULE` in the C API. 225 /// 226 /// C header: [`include/linux/init.h`](srctree/include/linux/init.h) 227 pub struct ThisModule(*mut bindings::module); 228 229 // SAFETY: `THIS_MODULE` may be used from all threads within a module. 230 unsafe impl Sync for ThisModule {} 231 232 impl ThisModule { 233 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer. 234 /// 235 /// # Safety 236 /// 237 /// The pointer must be equal to the right `THIS_MODULE`. 238 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule { 239 ThisModule(ptr) 240 } 241 242 /// Access the raw pointer for this module. 243 /// 244 /// It is up to the user to use it correctly. 245 pub const fn as_ptr(&self) -> *mut bindings::module { 246 self.0 247 } 248 } 249 250 #[cfg(not(testlib))] 251 #[panic_handler] 252 fn panic(info: &core::panic::PanicInfo<'_>) -> ! { 253 pr_emerg!("{}\n", info); 254 // SAFETY: FFI call. 255 unsafe { bindings::BUG() }; 256 } 257 258 /// Produces a pointer to an object from a pointer to one of its fields. 259 /// 260 /// If you encounter a type mismatch due to the [`Opaque`] type, then use [`Opaque::cast_into`] or 261 /// [`Opaque::cast_from`] to resolve the mismatch. 262 /// 263 /// [`Opaque`]: crate::types::Opaque 264 /// [`Opaque::cast_into`]: crate::types::Opaque::cast_into 265 /// [`Opaque::cast_from`]: crate::types::Opaque::cast_from 266 /// 267 /// # Safety 268 /// 269 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in 270 /// bounds of the same allocation. 271 /// 272 /// # Examples 273 /// 274 /// ``` 275 /// # use kernel::container_of; 276 /// struct Test { 277 /// a: u64, 278 /// b: u32, 279 /// } 280 /// 281 /// let test = Test { a: 10, b: 20 }; 282 /// let b_ptr: *const _ = &test.b; 283 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be 284 /// // in-bounds of the same allocation as `b_ptr`. 285 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) }; 286 /// assert!(core::ptr::eq(&test, test_alias)); 287 /// ``` 288 #[macro_export] 289 macro_rules! container_of { 290 ($field_ptr:expr, $Container:ty, $($fields:tt)*) => {{ 291 let offset: usize = ::core::mem::offset_of!($Container, $($fields)*); 292 let field_ptr = $field_ptr; 293 let container_ptr = field_ptr.byte_sub(offset).cast::<$Container>(); 294 $crate::assert_same_type(field_ptr, (&raw const (*container_ptr).$($fields)*).cast_mut()); 295 container_ptr 296 }} 297 } 298 299 /// Helper for [`container_of!`]. 300 #[doc(hidden)] 301 pub fn assert_same_type<T>(_: T, _: T) {} 302 303 /// Helper for `.rs.S` files. 304 #[doc(hidden)] 305 #[macro_export] 306 macro_rules! concat_literals { 307 ($( $asm:literal )* ) => { 308 ::core::concat!($($asm),*) 309 }; 310 } 311 312 /// Wrapper around `asm!` configured for use in the kernel. 313 /// 314 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 315 /// syntax. 316 // For x86, `asm!` uses intel syntax by default, but we want to use at&t syntax in the kernel. 317 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] 318 #[macro_export] 319 macro_rules! asm { 320 ($($asm:expr),* ; $($rest:tt)*) => { 321 ::core::arch::asm!( $($asm)*, options(att_syntax), $($rest)* ) 322 }; 323 } 324 325 /// Wrapper around `asm!` configured for use in the kernel. 326 /// 327 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 328 /// syntax. 329 // For non-x86 arches we just pass through to `asm!`. 330 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))] 331 #[macro_export] 332 macro_rules! asm { 333 ($($asm:expr),* ; $($rest:tt)*) => { 334 ::core::arch::asm!( $($asm)*, $($rest)* ) 335 }; 336 } 337 338 /// Gets the C string file name of a [`Location`]. 339 /// 340 /// If `Location::file_as_c_str()` is not available, returns a string that warns about it. 341 /// 342 /// [`Location`]: core::panic::Location 343 /// 344 /// # Examples 345 /// 346 /// ``` 347 /// # use kernel::file_from_location; 348 /// 349 /// #[track_caller] 350 /// fn foo() { 351 /// let caller = core::panic::Location::caller(); 352 /// 353 /// // Output: 354 /// // - A path like "rust/kernel/example.rs" if `file_as_c_str()` is available. 355 /// // - "<Location::file_as_c_str() not supported>" otherwise. 356 /// let caller_file = file_from_location(caller); 357 /// 358 /// // Prints out the message with caller's file name. 359 /// pr_info!("foo() called in file {caller_file:?}\n"); 360 /// 361 /// # if cfg!(CONFIG_RUSTC_HAS_FILE_WITH_NUL) { 362 /// # assert_eq!(Ok(caller.file()), caller_file.to_str()); 363 /// # } 364 /// } 365 /// 366 /// # foo(); 367 /// ``` 368 #[inline] 369 pub fn file_from_location<'a>(loc: &'a core::panic::Location<'a>) -> &'a core::ffi::CStr { 370 #[cfg(CONFIG_RUSTC_HAS_FILE_AS_C_STR)] 371 { 372 loc.file_as_c_str() 373 } 374 375 #[cfg(all(CONFIG_RUSTC_HAS_FILE_WITH_NUL, not(CONFIG_RUSTC_HAS_FILE_AS_C_STR)))] 376 { 377 loc.file_with_nul() 378 } 379 380 #[cfg(not(CONFIG_RUSTC_HAS_FILE_WITH_NUL))] 381 { 382 let _ = loc; 383 c"<Location::file_as_c_str() not supported>" 384 } 385 } 386