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