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