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