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