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 pid_namespace; 49 pub mod prelude; 50 pub mod print; 51 pub mod rbtree; 52 pub mod security; 53 pub mod seq_file; 54 pub mod sizes; 55 mod static_assert; 56 #[doc(hidden)] 57 pub mod std_vendor; 58 pub mod str; 59 pub mod sync; 60 pub mod task; 61 pub mod time; 62 pub mod tracepoint; 63 pub mod types; 64 pub mod uaccess; 65 pub mod workqueue; 66 67 #[doc(hidden)] 68 pub use bindings; 69 pub use macros; 70 pub use uapi; 71 72 #[doc(hidden)] 73 pub use build_error::build_error; 74 75 /// Prefix to appear before log messages printed from within the `kernel` crate. 76 const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; 77 78 /// The top level entrypoint to implementing a kernel module. 79 /// 80 /// For any teardown or cleanup operations, your type may implement [`Drop`]. 81 pub trait Module: Sized + Sync + Send { 82 /// Called at module initialization time. 83 /// 84 /// Use this method to perform whatever setup or registration your module 85 /// should do. 86 /// 87 /// Equivalent to the `module_init` macro in the C API. 88 fn init(module: &'static ThisModule) -> error::Result<Self>; 89 } 90 91 /// Equivalent to `THIS_MODULE` in the C API. 92 /// 93 /// C header: [`include/linux/export.h`](srctree/include/linux/export.h) 94 pub struct ThisModule(*mut bindings::module); 95 96 // SAFETY: `THIS_MODULE` may be used from all threads within a module. 97 unsafe impl Sync for ThisModule {} 98 99 impl ThisModule { 100 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer. 101 /// 102 /// # Safety 103 /// 104 /// The pointer must be equal to the right `THIS_MODULE`. 105 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule { 106 ThisModule(ptr) 107 } 108 109 /// Access the raw pointer for this module. 110 /// 111 /// It is up to the user to use it correctly. 112 pub const fn as_ptr(&self) -> *mut bindings::module { 113 self.0 114 } 115 } 116 117 #[cfg(not(any(testlib, test)))] 118 #[panic_handler] 119 fn panic(info: &core::panic::PanicInfo<'_>) -> ! { 120 pr_emerg!("{}\n", info); 121 // SAFETY: FFI call. 122 unsafe { bindings::BUG() }; 123 } 124 125 /// Produces a pointer to an object from a pointer to one of its fields. 126 /// 127 /// # Safety 128 /// 129 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in 130 /// bounds of the same allocation. 131 /// 132 /// # Examples 133 /// 134 /// ``` 135 /// # use kernel::container_of; 136 /// struct Test { 137 /// a: u64, 138 /// b: u32, 139 /// } 140 /// 141 /// let test = Test { a: 10, b: 20 }; 142 /// let b_ptr = &test.b; 143 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be 144 /// // in-bounds of the same allocation as `b_ptr`. 145 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) }; 146 /// assert!(core::ptr::eq(&test, test_alias)); 147 /// ``` 148 #[macro_export] 149 macro_rules! container_of { 150 ($ptr:expr, $type:ty, $($f:tt)*) => {{ 151 let ptr = $ptr as *const _ as *const u8; 152 let offset: usize = ::core::mem::offset_of!($type, $($f)*); 153 ptr.sub(offset) as *const $type 154 }} 155 } 156 157 /// Helper for `.rs.S` files. 158 #[doc(hidden)] 159 #[macro_export] 160 macro_rules! concat_literals { 161 ($( $asm:literal )* ) => { 162 ::core::concat!($($asm),*) 163 }; 164 } 165 166 /// Wrapper around `asm!` configured for use in the kernel. 167 /// 168 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 169 /// syntax. 170 // For x86, `asm!` uses intel syntax by default, but we want to use at&t syntax in the kernel. 171 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] 172 #[macro_export] 173 macro_rules! asm { 174 ($($asm:expr),* ; $($rest:tt)*) => { 175 ::core::arch::asm!( $($asm)*, options(att_syntax), $($rest)* ) 176 }; 177 } 178 179 /// Wrapper around `asm!` configured for use in the kernel. 180 /// 181 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 182 /// syntax. 183 // For non-x86 arches we just pass through to `asm!`. 184 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))] 185 #[macro_export] 186 macro_rules! asm { 187 ($($asm:expr),* ; $($rest:tt)*) => { 188 ::core::arch::asm!( $($asm)*, $($rest)* ) 189 }; 190 } 191