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 1.89.0. 20 #![feature(generic_arg_infer)] 21 // 22 // Expected to become stable. 23 #![feature(arbitrary_self_types)] 24 #![feature(derive_coerce_pointee)] 25 // 26 // To be determined. 27 #![feature(used_with_arg)] 28 // 29 // `feature(file_with_nul)` is stable since Rust 1.92.0. Before Rust 1.89.0, it did not exist, so 30 // enable it conditionally. 31 #![cfg_attr(CONFIG_RUSTC_HAS_FILE_WITH_NUL, feature(file_with_nul))] 32 33 // Ensure conditional compilation based on the kernel configuration works; 34 // otherwise we may silently break things like initcall handling. 35 #[cfg(not(CONFIG_RUST))] 36 compile_error!("Missing kernel configuration for conditional compilation"); 37 38 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate). 39 extern crate self as kernel; 40 41 pub use ffi; 42 43 pub mod acpi; 44 pub mod alloc; 45 #[cfg(CONFIG_AUXILIARY_BUS)] 46 pub mod auxiliary; 47 pub mod bitmap; 48 pub mod bits; 49 #[cfg(CONFIG_BLOCK)] 50 pub mod block; 51 pub mod bug; 52 pub mod build_assert; 53 pub mod clk; 54 #[cfg(CONFIG_CONFIGFS_FS)] 55 pub mod configfs; 56 pub mod cpu; 57 #[cfg(CONFIG_CPU_FREQ)] 58 pub mod cpufreq; 59 pub mod cpumask; 60 pub mod cred; 61 pub mod debugfs; 62 pub mod device; 63 pub mod device_id; 64 pub mod devres; 65 pub mod dma; 66 pub mod driver; 67 #[cfg(CONFIG_DRM = "y")] 68 pub mod drm; 69 pub mod error; 70 pub mod faux; 71 #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] 72 pub mod firmware; 73 pub mod fmt; 74 pub mod fs; 75 #[cfg(CONFIG_GPU_BUDDY = "y")] 76 pub mod gpu; 77 #[cfg(CONFIG_I2C = "y")] 78 pub mod i2c; 79 pub mod id_pool; 80 #[doc(hidden)] 81 pub mod impl_flags; 82 pub mod init; 83 pub mod interop; 84 pub mod io; 85 pub mod ioctl; 86 pub mod iommu; 87 pub mod iov; 88 pub mod irq; 89 pub mod jump_label; 90 #[cfg(CONFIG_KUNIT)] 91 pub mod kunit; 92 pub mod list; 93 pub mod maple_tree; 94 pub mod miscdevice; 95 pub mod mm; 96 pub mod module_param; 97 #[cfg(CONFIG_NET)] 98 pub mod net; 99 pub mod num; 100 pub mod of; 101 #[cfg(CONFIG_PM_OPP)] 102 pub mod opp; 103 pub mod page; 104 #[cfg(CONFIG_PCI)] 105 pub mod pci; 106 pub mod pid_namespace; 107 pub mod platform; 108 pub mod prelude; 109 pub mod print; 110 pub mod processor; 111 pub mod ptr; 112 #[cfg(CONFIG_RUST_PWM_ABSTRACTIONS)] 113 pub mod pwm; 114 pub mod rbtree; 115 pub mod regulator; 116 pub mod revocable; 117 pub mod safety; 118 pub mod scatterlist; 119 pub mod security; 120 pub mod seq_file; 121 pub mod sizes; 122 #[cfg(CONFIG_SOC_BUS)] 123 pub mod soc; 124 #[doc(hidden)] 125 pub mod std_vendor; 126 pub mod str; 127 pub mod sync; 128 pub mod task; 129 pub mod time; 130 pub mod tracepoint; 131 pub mod transmute; 132 pub mod types; 133 pub mod uaccess; 134 #[cfg(CONFIG_USB = "y")] 135 pub mod usb; 136 pub mod workqueue; 137 pub mod xarray; 138 139 #[doc(hidden)] 140 pub use bindings; 141 pub use macros; 142 pub use uapi; 143 144 /// Prefix to appear before log messages printed from within the `kernel` crate. 145 const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; 146 147 /// The top level entrypoint to implementing a kernel module. 148 /// 149 /// For any teardown or cleanup operations, your type may implement [`Drop`]. 150 pub trait Module: Sized + Sync + Send { 151 /// Called at module initialization time. 152 /// 153 /// Use this method to perform whatever setup or registration your module 154 /// should do. 155 /// 156 /// Equivalent to the `module_init` macro in the C API. 157 fn init(module: &'static ThisModule) -> error::Result<Self>; 158 } 159 160 /// A module that is pinned and initialised in-place. 161 pub trait InPlaceModule: Sync + Send { 162 /// Creates an initialiser for the module. 163 /// 164 /// It is called when the module is loaded. 165 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error>; 166 } 167 168 impl<T: Module> InPlaceModule for T { 169 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error> { 170 let initer = move |slot: *mut Self| { 171 let m = <Self as Module>::init(module)?; 172 173 // SAFETY: `slot` is valid for write per the contract with `pin_init_from_closure`. 174 unsafe { slot.write(m) }; 175 Ok(()) 176 }; 177 178 // SAFETY: On success, `initer` always fully initialises an instance of `Self`. 179 unsafe { pin_init::pin_init_from_closure(initer) } 180 } 181 } 182 183 /// Metadata attached to a [`Module`] or [`InPlaceModule`]. 184 pub trait ModuleMetadata { 185 /// The name of the module as specified in the `module!` macro. 186 const NAME: &'static crate::str::CStr; 187 } 188 189 /// Equivalent to `THIS_MODULE` in the C API. 190 /// 191 /// C header: [`include/linux/init.h`](srctree/include/linux/init.h) 192 pub struct ThisModule(*mut bindings::module); 193 194 // SAFETY: `THIS_MODULE` may be used from all threads within a module. 195 unsafe impl Sync for ThisModule {} 196 197 impl ThisModule { 198 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer. 199 /// 200 /// # Safety 201 /// 202 /// The pointer must be equal to the right `THIS_MODULE`. 203 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule { 204 ThisModule(ptr) 205 } 206 207 /// Access the raw pointer for this module. 208 /// 209 /// It is up to the user to use it correctly. 210 pub const fn as_ptr(&self) -> *mut bindings::module { 211 self.0 212 } 213 } 214 215 #[cfg(not(testlib))] 216 #[panic_handler] 217 fn panic(info: &core::panic::PanicInfo<'_>) -> ! { 218 pr_emerg!("{}\n", info); 219 // SAFETY: FFI call. 220 unsafe { bindings::BUG() }; 221 } 222 223 /// Produces a pointer to an object from a pointer to one of its fields. 224 /// 225 /// If you encounter a type mismatch due to the [`Opaque`] type, then use [`Opaque::cast_into`] or 226 /// [`Opaque::cast_from`] to resolve the mismatch. 227 /// 228 /// [`Opaque`]: crate::types::Opaque 229 /// [`Opaque::cast_into`]: crate::types::Opaque::cast_into 230 /// [`Opaque::cast_from`]: crate::types::Opaque::cast_from 231 /// 232 /// # Safety 233 /// 234 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in 235 /// bounds of the same allocation. 236 /// 237 /// # Examples 238 /// 239 /// ``` 240 /// # use kernel::container_of; 241 /// struct Test { 242 /// a: u64, 243 /// b: u32, 244 /// } 245 /// 246 /// let test = Test { a: 10, b: 20 }; 247 /// let b_ptr: *const _ = &test.b; 248 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be 249 /// // in-bounds of the same allocation as `b_ptr`. 250 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) }; 251 /// assert!(core::ptr::eq(&test, test_alias)); 252 /// ``` 253 #[macro_export] 254 macro_rules! container_of { 255 ($field_ptr:expr, $Container:ty, $($fields:tt)*) => {{ 256 let offset: usize = ::core::mem::offset_of!($Container, $($fields)*); 257 let field_ptr = $field_ptr; 258 let container_ptr = field_ptr.byte_sub(offset).cast::<$Container>(); 259 $crate::assert_same_type(field_ptr, (&raw const (*container_ptr).$($fields)*).cast_mut()); 260 container_ptr 261 }} 262 } 263 264 /// Helper for [`container_of!`]. 265 #[doc(hidden)] 266 pub fn assert_same_type<T>(_: T, _: T) {} 267 268 /// Helper for `.rs.S` files. 269 #[doc(hidden)] 270 #[macro_export] 271 macro_rules! concat_literals { 272 ($( $asm:literal )* ) => { 273 ::core::concat!($($asm),*) 274 }; 275 } 276 277 /// Wrapper around `asm!` configured for use in the kernel. 278 /// 279 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 280 /// syntax. 281 // For x86, `asm!` uses intel syntax by default, but we want to use at&t syntax in the kernel. 282 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] 283 #[macro_export] 284 macro_rules! asm { 285 ($($asm:expr),* ; $($rest:tt)*) => { 286 ::core::arch::asm!( $($asm)*, options(att_syntax), $($rest)* ) 287 }; 288 } 289 290 /// Wrapper around `asm!` configured for use in the kernel. 291 /// 292 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 293 /// syntax. 294 // For non-x86 arches we just pass through to `asm!`. 295 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))] 296 #[macro_export] 297 macro_rules! asm { 298 ($($asm:expr),* ; $($rest:tt)*) => { 299 ::core::arch::asm!( $($asm)*, $($rest)* ) 300 }; 301 } 302 303 /// Gets the C string file name of a [`Location`]. 304 /// 305 /// If `Location::file_as_c_str()` is not available, returns a string that warns about it. 306 /// 307 /// [`Location`]: core::panic::Location 308 /// 309 /// # Examples 310 /// 311 /// ``` 312 /// # use kernel::file_from_location; 313 /// 314 /// #[track_caller] 315 /// fn foo() { 316 /// let caller = core::panic::Location::caller(); 317 /// 318 /// // Output: 319 /// // - A path like "rust/kernel/example.rs" if `file_as_c_str()` is available. 320 /// // - "<Location::file_as_c_str() not supported>" otherwise. 321 /// let caller_file = file_from_location(caller); 322 /// 323 /// // Prints out the message with caller's file name. 324 /// pr_info!("foo() called in file {caller_file:?}\n"); 325 /// 326 /// # if cfg!(CONFIG_RUSTC_HAS_FILE_WITH_NUL) { 327 /// # assert_eq!(Ok(caller.file()), caller_file.to_str()); 328 /// # } 329 /// } 330 /// 331 /// # foo(); 332 /// ``` 333 #[inline] 334 pub fn file_from_location<'a>(loc: &'a core::panic::Location<'a>) -> &'a core::ffi::CStr { 335 #[cfg(CONFIG_RUSTC_HAS_FILE_AS_C_STR)] 336 { 337 loc.file_as_c_str() 338 } 339 340 #[cfg(all(CONFIG_RUSTC_HAS_FILE_WITH_NUL, not(CONFIG_RUSTC_HAS_FILE_AS_C_STR)))] 341 { 342 loc.file_with_nul() 343 } 344 345 #[cfg(not(CONFIG_RUSTC_HAS_FILE_WITH_NUL))] 346 { 347 let _ = loc; 348 c"<Location::file_as_c_str() not supported>" 349 } 350 } 351