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 #![feature(arbitrary_self_types)] 16 #![cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, feature(derive_coerce_pointee))] 17 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(coerce_unsized))] 18 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(dispatch_from_dyn))] 19 #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(unsize))] 20 #![feature(inline_const)] 21 #![feature(lint_reasons)] 22 // Stable in Rust 1.82 23 #![feature(raw_ref_op)] 24 // Stable in Rust 1.83 25 #![feature(const_maybe_uninit_as_mut_ptr)] 26 #![feature(const_mut_refs)] 27 #![feature(const_ptr_write)] 28 #![feature(const_refs_to_cell)] 29 30 // Ensure conditional compilation based on the kernel configuration works; 31 // otherwise we may silently break things like initcall handling. 32 #[cfg(not(CONFIG_RUST))] 33 compile_error!("Missing kernel configuration for conditional compilation"); 34 35 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate). 36 extern crate self as kernel; 37 38 pub use ffi; 39 40 pub mod alloc; 41 #[cfg(CONFIG_AUXILIARY_BUS)] 42 pub mod auxiliary; 43 #[cfg(CONFIG_BLOCK)] 44 pub mod block; 45 #[doc(hidden)] 46 pub mod build_assert; 47 pub mod cred; 48 pub mod device; 49 pub mod device_id; 50 pub mod devres; 51 pub mod dma; 52 pub mod driver; 53 #[cfg(CONFIG_DRM = "y")] 54 pub mod drm; 55 pub mod error; 56 pub mod faux; 57 #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] 58 pub mod firmware; 59 pub mod fs; 60 pub mod init; 61 pub mod io; 62 pub mod ioctl; 63 pub mod jump_label; 64 #[cfg(CONFIG_KUNIT)] 65 pub mod kunit; 66 pub mod list; 67 pub mod miscdevice; 68 #[cfg(CONFIG_NET)] 69 pub mod net; 70 pub mod of; 71 pub mod page; 72 #[cfg(CONFIG_PCI)] 73 pub mod pci; 74 pub mod pid_namespace; 75 pub mod platform; 76 pub mod prelude; 77 pub mod print; 78 pub mod rbtree; 79 pub mod revocable; 80 pub mod security; 81 pub mod seq_file; 82 pub mod sizes; 83 mod static_assert; 84 #[doc(hidden)] 85 pub mod std_vendor; 86 pub mod str; 87 pub mod sync; 88 pub mod task; 89 pub mod time; 90 pub mod tracepoint; 91 pub mod transmute; 92 pub mod types; 93 pub mod uaccess; 94 pub mod workqueue; 95 96 #[doc(hidden)] 97 pub use bindings; 98 pub use macros; 99 pub use uapi; 100 101 /// Prefix to appear before log messages printed from within the `kernel` crate. 102 const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; 103 104 /// The top level entrypoint to implementing a kernel module. 105 /// 106 /// For any teardown or cleanup operations, your type may implement [`Drop`]. 107 pub trait Module: Sized + Sync + Send { 108 /// Called at module initialization time. 109 /// 110 /// Use this method to perform whatever setup or registration your module 111 /// should do. 112 /// 113 /// Equivalent to the `module_init` macro in the C API. 114 fn init(module: &'static ThisModule) -> error::Result<Self>; 115 } 116 117 /// A module that is pinned and initialised in-place. 118 pub trait InPlaceModule: Sync + Send { 119 /// Creates an initialiser for the module. 120 /// 121 /// It is called when the module is loaded. 122 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error>; 123 } 124 125 impl<T: Module> InPlaceModule for T { 126 fn init(module: &'static ThisModule) -> impl pin_init::PinInit<Self, error::Error> { 127 let initer = move |slot: *mut Self| { 128 let m = <Self as Module>::init(module)?; 129 130 // SAFETY: `slot` is valid for write per the contract with `pin_init_from_closure`. 131 unsafe { slot.write(m) }; 132 Ok(()) 133 }; 134 135 // SAFETY: On success, `initer` always fully initialises an instance of `Self`. 136 unsafe { pin_init::pin_init_from_closure(initer) } 137 } 138 } 139 140 /// Metadata attached to a [`Module`] or [`InPlaceModule`]. 141 pub trait ModuleMetadata { 142 /// The name of the module as specified in the `module!` macro. 143 const NAME: &'static crate::str::CStr; 144 } 145 146 /// Equivalent to `THIS_MODULE` in the C API. 147 /// 148 /// C header: [`include/linux/init.h`](srctree/include/linux/init.h) 149 pub struct ThisModule(*mut bindings::module); 150 151 // SAFETY: `THIS_MODULE` may be used from all threads within a module. 152 unsafe impl Sync for ThisModule {} 153 154 impl ThisModule { 155 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer. 156 /// 157 /// # Safety 158 /// 159 /// The pointer must be equal to the right `THIS_MODULE`. 160 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule { 161 ThisModule(ptr) 162 } 163 164 /// Access the raw pointer for this module. 165 /// 166 /// It is up to the user to use it correctly. 167 pub const fn as_ptr(&self) -> *mut bindings::module { 168 self.0 169 } 170 } 171 172 #[cfg(not(any(testlib, test)))] 173 #[panic_handler] 174 fn panic(info: &core::panic::PanicInfo<'_>) -> ! { 175 pr_emerg!("{}\n", info); 176 // SAFETY: FFI call. 177 unsafe { bindings::BUG() }; 178 } 179 180 /// Produces a pointer to an object from a pointer to one of its fields. 181 /// 182 /// # Safety 183 /// 184 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in 185 /// bounds of the same allocation. 186 /// 187 /// # Examples 188 /// 189 /// ``` 190 /// # use kernel::container_of; 191 /// struct Test { 192 /// a: u64, 193 /// b: u32, 194 /// } 195 /// 196 /// let test = Test { a: 10, b: 20 }; 197 /// let b_ptr = &test.b; 198 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be 199 /// // in-bounds of the same allocation as `b_ptr`. 200 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) }; 201 /// assert!(core::ptr::eq(&test, test_alias)); 202 /// ``` 203 #[macro_export] 204 macro_rules! container_of { 205 ($ptr:expr, $type:ty, $($f:tt)*) => {{ 206 let ptr = $ptr as *const _ as *const u8; 207 let offset: usize = ::core::mem::offset_of!($type, $($f)*); 208 ptr.sub(offset) as *const $type 209 }} 210 } 211 212 /// Helper for `.rs.S` files. 213 #[doc(hidden)] 214 #[macro_export] 215 macro_rules! concat_literals { 216 ($( $asm:literal )* ) => { 217 ::core::concat!($($asm),*) 218 }; 219 } 220 221 /// Wrapper around `asm!` configured for use in the kernel. 222 /// 223 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 224 /// syntax. 225 // For x86, `asm!` uses intel syntax by default, but we want to use at&t syntax in the kernel. 226 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] 227 #[macro_export] 228 macro_rules! asm { 229 ($($asm:expr),* ; $($rest:tt)*) => { 230 ::core::arch::asm!( $($asm)*, options(att_syntax), $($rest)* ) 231 }; 232 } 233 234 /// Wrapper around `asm!` configured for use in the kernel. 235 /// 236 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 237 /// syntax. 238 // For non-x86 arches we just pass through to `asm!`. 239 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))] 240 #[macro_export] 241 macro_rules! asm { 242 ($($asm:expr),* ; $($rest:tt)*) => { 243 ::core::arch::asm!( $($asm)*, $($rest)* ) 244 }; 245 } 246