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