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(coerce_unsized)] 16 #![feature(dispatch_from_dyn)] 17 #![feature(new_uninit)] 18 #![feature(receiver_trait)] 19 #![feature(unsize)] 20 21 // Ensure conditional compilation based on the kernel configuration works; 22 // otherwise we may silently break things like initcall handling. 23 #[cfg(not(CONFIG_RUST))] 24 compile_error!("Missing kernel configuration for conditional compilation"); 25 26 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate). 27 extern crate self as kernel; 28 29 pub mod alloc; 30 #[cfg(CONFIG_BLOCK)] 31 pub mod block; 32 mod build_assert; 33 pub mod cred; 34 pub mod device; 35 pub mod error; 36 #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] 37 pub mod firmware; 38 pub mod fs; 39 pub mod init; 40 pub mod ioctl; 41 pub mod jump_label; 42 #[cfg(CONFIG_KUNIT)] 43 pub mod kunit; 44 pub mod list; 45 #[cfg(CONFIG_NET)] 46 pub mod net; 47 pub mod page; 48 pub mod prelude; 49 pub mod print; 50 pub mod rbtree; 51 pub mod security; 52 pub mod seq_file; 53 pub mod sizes; 54 mod static_assert; 55 #[doc(hidden)] 56 pub mod std_vendor; 57 pub mod str; 58 pub mod sync; 59 pub mod task; 60 pub mod time; 61 pub mod tracepoint; 62 pub mod types; 63 pub mod uaccess; 64 pub mod workqueue; 65 66 #[doc(hidden)] 67 pub use bindings; 68 pub use macros; 69 pub use uapi; 70 71 #[doc(hidden)] 72 pub use build_error::build_error; 73 74 /// Prefix to appear before log messages printed from within the `kernel` crate. 75 const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; 76 77 /// The top level entrypoint to implementing a kernel module. 78 /// 79 /// For any teardown or cleanup operations, your type may implement [`Drop`]. 80 pub trait Module: Sized + Sync + Send { 81 /// Called at module initialization time. 82 /// 83 /// Use this method to perform whatever setup or registration your module 84 /// should do. 85 /// 86 /// Equivalent to the `module_init` macro in the C API. 87 fn init(module: &'static ThisModule) -> error::Result<Self>; 88 } 89 90 /// Equivalent to `THIS_MODULE` in the C API. 91 /// 92 /// C header: [`include/linux/export.h`](srctree/include/linux/export.h) 93 pub struct ThisModule(*mut bindings::module); 94 95 // SAFETY: `THIS_MODULE` may be used from all threads within a module. 96 unsafe impl Sync for ThisModule {} 97 98 impl ThisModule { 99 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer. 100 /// 101 /// # Safety 102 /// 103 /// The pointer must be equal to the right `THIS_MODULE`. 104 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule { 105 ThisModule(ptr) 106 } 107 108 /// Access the raw pointer for this module. 109 /// 110 /// It is up to the user to use it correctly. 111 pub const fn as_ptr(&self) -> *mut bindings::module { 112 self.0 113 } 114 } 115 116 #[cfg(not(any(testlib, test)))] 117 #[panic_handler] 118 fn panic(info: &core::panic::PanicInfo<'_>) -> ! { 119 pr_emerg!("{}\n", info); 120 // SAFETY: FFI call. 121 unsafe { bindings::BUG() }; 122 } 123 124 /// Produces a pointer to an object from a pointer to one of its fields. 125 /// 126 /// # Safety 127 /// 128 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in 129 /// bounds of the same allocation. 130 /// 131 /// # Examples 132 /// 133 /// ``` 134 /// # use kernel::container_of; 135 /// struct Test { 136 /// a: u64, 137 /// b: u32, 138 /// } 139 /// 140 /// let test = Test { a: 10, b: 20 }; 141 /// let b_ptr = &test.b; 142 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be 143 /// // in-bounds of the same allocation as `b_ptr`. 144 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) }; 145 /// assert!(core::ptr::eq(&test, test_alias)); 146 /// ``` 147 #[macro_export] 148 macro_rules! container_of { 149 ($ptr:expr, $type:ty, $($f:tt)*) => {{ 150 let ptr = $ptr as *const _ as *const u8; 151 let offset: usize = ::core::mem::offset_of!($type, $($f)*); 152 ptr.sub(offset) as *const $type 153 }} 154 } 155 156 /// Helper for `.rs.S` files. 157 #[doc(hidden)] 158 #[macro_export] 159 macro_rules! concat_literals { 160 ($( $asm:literal )* ) => { 161 ::core::concat!($($asm),*) 162 }; 163 } 164 165 /// Wrapper around `asm!` configured for use in the kernel. 166 /// 167 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 168 /// syntax. 169 // For x86, `asm!` uses intel syntax by default, but we want to use at&t syntax in the kernel. 170 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] 171 #[macro_export] 172 macro_rules! asm { 173 ($($asm:expr),* ; $($rest:tt)*) => { 174 ::core::arch::asm!( $($asm)*, options(att_syntax), $($rest)* ) 175 }; 176 } 177 178 /// Wrapper around `asm!` configured for use in the kernel. 179 /// 180 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 181 /// syntax. 182 // For non-x86 arches we just pass through to `asm!`. 183 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))] 184 #[macro_export] 185 macro_rules! asm { 186 ($($asm:expr),* ; $($rest:tt)*) => { 187 ::core::arch::asm!( $($asm)*, $($rest)* ) 188 }; 189 } 190