1 // SPDX-License-Identifier: GPL-2.0 2 3 //! Crate for all kernel procedural macros. 4 5 #[macro_use] 6 mod quote; 7 mod concat_idents; 8 mod helpers; 9 mod module; 10 mod paste; 11 mod pin_data; 12 mod pinned_drop; 13 mod vtable; 14 mod zeroable; 15 16 use proc_macro::TokenStream; 17 18 /// Declares a kernel module. 19 /// 20 /// The `type` argument should be a type which implements the [`Module`] 21 /// trait. Also accepts various forms of kernel metadata. 22 /// 23 /// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h) 24 /// 25 /// [`Module`]: ../kernel/trait.Module.html 26 /// 27 /// # Examples 28 /// 29 /// ```ignore 30 /// use kernel::prelude::*; 31 /// 32 /// module!{ 33 /// type: MyModule, 34 /// name: "my_kernel_module", 35 /// author: "Rust for Linux Contributors", 36 /// description: "My very own kernel module!", 37 /// license: "GPL", 38 /// } 39 /// 40 /// struct MyModule; 41 /// 42 /// impl kernel::Module for MyModule { 43 /// fn init() -> Result<Self> { 44 /// // If the parameter is writeable, then the kparam lock must be 45 /// // taken to read the parameter: 46 /// { 47 /// let lock = THIS_MODULE.kernel_param_lock(); 48 /// pr_info!("i32 param is: {}\n", writeable_i32.read(&lock)); 49 /// } 50 /// // If the parameter is read only, it can be read without locking 51 /// // the kernel parameters: 52 /// pr_info!("i32 param is: {}\n", my_i32.read()); 53 /// Ok(Self) 54 /// } 55 /// } 56 /// ``` 57 /// 58 /// # Supported argument types 59 /// - `type`: type which implements the [`Module`] trait (required). 60 /// - `name`: byte array of the name of the kernel module (required). 61 /// - `author`: byte array of the author of the kernel module. 62 /// - `description`: byte array of the description of the kernel module. 63 /// - `license`: byte array of the license of the kernel module (required). 64 /// - `alias`: byte array of alias name of the kernel module. 65 #[proc_macro] 66 pub fn module(ts: TokenStream) -> TokenStream { 67 module::module(ts) 68 } 69 70 /// Declares or implements a vtable trait. 71 /// 72 /// Linux's use of pure vtables is very close to Rust traits, but they differ 73 /// in how unimplemented functions are represented. In Rust, traits can provide 74 /// default implementation for all non-required methods (and the default 75 /// implementation could just return `Error::EINVAL`); Linux typically use C 76 /// `NULL` pointers to represent these functions. 77 /// 78 /// This attribute closes that gap. A trait can be annotated with the 79 /// `#[vtable]` attribute. Implementers of the trait will then also have to 80 /// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*` 81 /// associated constant bool for each method in the trait that is set to true if 82 /// the implementer has overridden the associated method. 83 /// 84 /// For a trait method to be optional, it must have a default implementation. 85 /// This is also the case for traits annotated with `#[vtable]`, but in this 86 /// case the default implementation will never be executed. The reason for this 87 /// is that the functions will be called through function pointers installed in 88 /// C side vtables. When an optional method is not implemented on a `#[vtable]` 89 /// trait, a NULL entry is installed in the vtable. Thus the default 90 /// implementation is never called. Since these traits are not designed to be 91 /// used on the Rust side, it should not be possible to call the default 92 /// implementation. This is done to ensure that we call the vtable methods 93 /// through the C vtable, and not through the Rust vtable. Therefore, the 94 /// default implementation should call `kernel::build_error`, which prevents 95 /// calls to this function at compile time: 96 /// 97 /// ```compile_fail 98 /// # use kernel::error::VTABLE_DEFAULT_ERROR; 99 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 100 /// ``` 101 /// 102 /// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`]. 103 /// 104 /// This macro should not be used when all functions are required. 105 /// 106 /// # Examples 107 /// 108 /// ```ignore 109 /// use kernel::error::VTABLE_DEFAULT_ERROR; 110 /// use kernel::prelude::*; 111 /// 112 /// // Declares a `#[vtable]` trait 113 /// #[vtable] 114 /// pub trait Operations: Send + Sync + Sized { 115 /// fn foo(&self) -> Result<()> { 116 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 117 /// } 118 /// 119 /// fn bar(&self) -> Result<()> { 120 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 121 /// } 122 /// } 123 /// 124 /// struct Foo; 125 /// 126 /// // Implements the `#[vtable]` trait 127 /// #[vtable] 128 /// impl Operations for Foo { 129 /// fn foo(&self) -> Result<()> { 130 /// # Err(EINVAL) 131 /// // ... 132 /// } 133 /// } 134 /// 135 /// assert_eq!(<Foo as Operations>::HAS_FOO, true); 136 /// assert_eq!(<Foo as Operations>::HAS_BAR, false); 137 /// ``` 138 /// 139 /// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html 140 #[proc_macro_attribute] 141 pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream { 142 vtable::vtable(attr, ts) 143 } 144 145 /// Concatenate two identifiers. 146 /// 147 /// This is useful in macros that need to declare or reference items with names 148 /// starting with a fixed prefix and ending in a user specified name. The resulting 149 /// identifier has the span of the second argument. 150 /// 151 /// # Examples 152 /// 153 /// ```ignore 154 /// use kernel::macro::concat_idents; 155 /// 156 /// macro_rules! pub_no_prefix { 157 /// ($prefix:ident, $($newname:ident),+) => { 158 /// $(pub(crate) const $newname: u32 = kernel::macros::concat_idents!($prefix, $newname);)+ 159 /// }; 160 /// } 161 /// 162 /// pub_no_prefix!( 163 /// binder_driver_return_protocol_, 164 /// BR_OK, 165 /// BR_ERROR, 166 /// BR_TRANSACTION, 167 /// BR_REPLY, 168 /// BR_DEAD_REPLY, 169 /// BR_TRANSACTION_COMPLETE, 170 /// BR_INCREFS, 171 /// BR_ACQUIRE, 172 /// BR_RELEASE, 173 /// BR_DECREFS, 174 /// BR_NOOP, 175 /// BR_SPAWN_LOOPER, 176 /// BR_DEAD_BINDER, 177 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 178 /// BR_FAILED_REPLY 179 /// ); 180 /// 181 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 182 /// ``` 183 #[proc_macro] 184 pub fn concat_idents(ts: TokenStream) -> TokenStream { 185 concat_idents::concat_idents(ts) 186 } 187 188 /// Used to specify the pinning information of the fields of a struct. 189 /// 190 /// This is somewhat similar in purpose as 191 /// [pin-project-lite](https://crates.io/crates/pin-project-lite). 192 /// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each 193 /// field you want to structurally pin. 194 /// 195 /// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`, 196 /// then `#[pin]` directs the type of initializer that is required. 197 /// 198 /// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this 199 /// macro, and change your `Drop` implementation to `PinnedDrop` annotated with 200 /// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care. 201 /// 202 /// # Examples 203 /// 204 /// ```rust,ignore 205 /// #[pin_data] 206 /// struct DriverData { 207 /// #[pin] 208 /// queue: Mutex<Vec<Command>>, 209 /// buf: Box<[u8; 1024 * 1024]>, 210 /// } 211 /// ``` 212 /// 213 /// ```rust,ignore 214 /// #[pin_data(PinnedDrop)] 215 /// struct DriverData { 216 /// #[pin] 217 /// queue: Mutex<Vec<Command>>, 218 /// buf: Box<[u8; 1024 * 1024]>, 219 /// raw_info: *mut Info, 220 /// } 221 /// 222 /// #[pinned_drop] 223 /// impl PinnedDrop for DriverData { 224 /// fn drop(self: Pin<&mut Self>) { 225 /// unsafe { bindings::destroy_info(self.raw_info) }; 226 /// } 227 /// } 228 /// ``` 229 /// 230 /// [`pin_init!`]: ../kernel/macro.pin_init.html 231 // ^ cannot use direct link, since `kernel` is not a dependency of `macros`. 232 #[proc_macro_attribute] 233 pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream { 234 pin_data::pin_data(inner, item) 235 } 236 237 /// Used to implement `PinnedDrop` safely. 238 /// 239 /// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`. 240 /// 241 /// # Examples 242 /// 243 /// ```rust,ignore 244 /// #[pin_data(PinnedDrop)] 245 /// struct DriverData { 246 /// #[pin] 247 /// queue: Mutex<Vec<Command>>, 248 /// buf: Box<[u8; 1024 * 1024]>, 249 /// raw_info: *mut Info, 250 /// } 251 /// 252 /// #[pinned_drop] 253 /// impl PinnedDrop for DriverData { 254 /// fn drop(self: Pin<&mut Self>) { 255 /// unsafe { bindings::destroy_info(self.raw_info) }; 256 /// } 257 /// } 258 /// ``` 259 #[proc_macro_attribute] 260 pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream { 261 pinned_drop::pinned_drop(args, input) 262 } 263 264 /// Paste identifiers together. 265 /// 266 /// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a 267 /// single identifier. 268 /// 269 /// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and 270 /// literals (lifetimes and documentation strings are not supported). There is a difference in 271 /// supported modifiers as well. 272 /// 273 /// # Example 274 /// 275 /// ```ignore 276 /// use kernel::macro::paste; 277 /// 278 /// macro_rules! pub_no_prefix { 279 /// ($prefix:ident, $($newname:ident),+) => { 280 /// paste! { 281 /// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+ 282 /// } 283 /// }; 284 /// } 285 /// 286 /// pub_no_prefix!( 287 /// binder_driver_return_protocol_, 288 /// BR_OK, 289 /// BR_ERROR, 290 /// BR_TRANSACTION, 291 /// BR_REPLY, 292 /// BR_DEAD_REPLY, 293 /// BR_TRANSACTION_COMPLETE, 294 /// BR_INCREFS, 295 /// BR_ACQUIRE, 296 /// BR_RELEASE, 297 /// BR_DECREFS, 298 /// BR_NOOP, 299 /// BR_SPAWN_LOOPER, 300 /// BR_DEAD_BINDER, 301 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 302 /// BR_FAILED_REPLY 303 /// ); 304 /// 305 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 306 /// ``` 307 /// 308 /// # Modifiers 309 /// 310 /// For each identifier, it is possible to attach one or multiple modifiers to 311 /// it. 312 /// 313 /// Currently supported modifiers are: 314 /// * `span`: change the span of concatenated identifier to the span of the specified token. By 315 /// default the span of the `[< >]` group is used. 316 /// * `lower`: change the identifier to lower case. 317 /// * `upper`: change the identifier to upper case. 318 /// 319 /// ```ignore 320 /// use kernel::macro::paste; 321 /// 322 /// macro_rules! pub_no_prefix { 323 /// ($prefix:ident, $($newname:ident),+) => { 324 /// kernel::macros::paste! { 325 /// $(pub(crate) const fn [<$newname:lower:span>]: u32 = [<$prefix $newname:span>];)+ 326 /// } 327 /// }; 328 /// } 329 /// 330 /// pub_no_prefix!( 331 /// binder_driver_return_protocol_, 332 /// BR_OK, 333 /// BR_ERROR, 334 /// BR_TRANSACTION, 335 /// BR_REPLY, 336 /// BR_DEAD_REPLY, 337 /// BR_TRANSACTION_COMPLETE, 338 /// BR_INCREFS, 339 /// BR_ACQUIRE, 340 /// BR_RELEASE, 341 /// BR_DECREFS, 342 /// BR_NOOP, 343 /// BR_SPAWN_LOOPER, 344 /// BR_DEAD_BINDER, 345 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 346 /// BR_FAILED_REPLY 347 /// ); 348 /// 349 /// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK); 350 /// ``` 351 /// 352 /// # Literals 353 /// 354 /// Literals can also be concatenated with other identifiers: 355 /// 356 /// ```ignore 357 /// macro_rules! create_numbered_fn { 358 /// ($name:literal, $val:literal) => { 359 /// kernel::macros::paste! { 360 /// fn [<some_ $name _fn $val>]() -> u32 { $val } 361 /// } 362 /// }; 363 /// } 364 /// 365 /// create_numbered_fn!("foo", 100); 366 /// 367 /// assert_eq!(some_foo_fn100(), 100) 368 /// ``` 369 /// 370 /// [`paste`]: https://docs.rs/paste/ 371 #[proc_macro] 372 pub fn paste(input: TokenStream) -> TokenStream { 373 let mut tokens = input.into_iter().collect(); 374 paste::expand(&mut tokens); 375 tokens.into_iter().collect() 376 } 377 378 /// Derives the [`Zeroable`] trait for the given struct. 379 /// 380 /// This can only be used for structs where every field implements the [`Zeroable`] trait. 381 /// 382 /// # Examples 383 /// 384 /// ```rust,ignore 385 /// #[derive(Zeroable)] 386 /// pub struct DriverData { 387 /// id: i64, 388 /// buf_ptr: *mut u8, 389 /// len: usize, 390 /// } 391 /// ``` 392 #[proc_macro_derive(Zeroable)] 393 pub fn derive_zeroable(input: TokenStream) -> TokenStream { 394 zeroable::derive(input) 395 } 396