1 // SPDX-License-Identifier: GPL-2.0 2 3 //! Crate for all kernel procedural macros. 4 5 // When fixdep scans this, it will find this string `CONFIG_RUSTC_VERSION_TEXT` 6 // and thus add a dependency on `include/config/RUSTC_VERSION_TEXT`, which is 7 // touched by Kconfig when the version string from the compiler changes. 8 9 #[macro_use] 10 mod quote; 11 mod concat_idents; 12 mod helpers; 13 mod module; 14 mod paste; 15 mod pin_data; 16 mod pinned_drop; 17 mod vtable; 18 mod zeroable; 19 20 use proc_macro::TokenStream; 21 22 /// Declares a kernel module. 23 /// 24 /// The `type` argument should be a type which implements the [`Module`] 25 /// trait. Also accepts various forms of kernel metadata. 26 /// 27 /// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h) 28 /// 29 /// [`Module`]: ../kernel/trait.Module.html 30 /// 31 /// # Examples 32 /// 33 /// ``` 34 /// use kernel::prelude::*; 35 /// 36 /// module!{ 37 /// type: MyModule, 38 /// name: "my_kernel_module", 39 /// author: "Rust for Linux Contributors", 40 /// description: "My very own kernel module!", 41 /// license: "GPL", 42 /// alias: ["alternate_module_name"], 43 /// } 44 /// 45 /// struct MyModule(i32); 46 /// 47 /// impl kernel::Module for MyModule { 48 /// fn init(_module: &'static ThisModule) -> Result<Self> { 49 /// let foo: i32 = 42; 50 /// pr_info!("I contain: {}\n", foo); 51 /// Ok(Self(foo)) 52 /// } 53 /// } 54 /// # fn main() {} 55 /// ``` 56 /// 57 /// ## Firmware 58 /// 59 /// The following example shows how to declare a kernel module that needs 60 /// to load binary firmware files. You need to specify the file names of 61 /// the firmware in the `firmware` field. The information is embedded 62 /// in the `modinfo` section of the kernel module. For example, a tool to 63 /// build an initramfs uses this information to put the firmware files into 64 /// the initramfs image. 65 /// 66 /// ``` 67 /// use kernel::prelude::*; 68 /// 69 /// module!{ 70 /// type: MyDeviceDriverModule, 71 /// name: "my_device_driver_module", 72 /// author: "Rust for Linux Contributors", 73 /// description: "My device driver requires firmware", 74 /// license: "GPL", 75 /// firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"], 76 /// } 77 /// 78 /// struct MyDeviceDriverModule; 79 /// 80 /// impl kernel::Module for MyDeviceDriverModule { 81 /// fn init(_module: &'static ThisModule) -> Result<Self> { 82 /// Ok(Self) 83 /// } 84 /// } 85 /// # fn main() {} 86 /// ``` 87 /// 88 /// # Supported argument types 89 /// - `type`: type which implements the [`Module`] trait (required). 90 /// - `name`: ASCII string literal of the name of the kernel module (required). 91 /// - `author`: string literal of the author of the kernel module. 92 /// - `description`: string literal of the description of the kernel module. 93 /// - `license`: ASCII string literal of the license of the kernel module (required). 94 /// - `alias`: array of ASCII string literals of the alias names of the kernel module. 95 /// - `firmware`: array of ASCII string literals of the firmware files of 96 /// the kernel module. 97 #[proc_macro] 98 pub fn module(ts: TokenStream) -> TokenStream { 99 module::module(ts) 100 } 101 102 /// Declares or implements a vtable trait. 103 /// 104 /// Linux's use of pure vtables is very close to Rust traits, but they differ 105 /// in how unimplemented functions are represented. In Rust, traits can provide 106 /// default implementation for all non-required methods (and the default 107 /// implementation could just return `Error::EINVAL`); Linux typically use C 108 /// `NULL` pointers to represent these functions. 109 /// 110 /// This attribute closes that gap. A trait can be annotated with the 111 /// `#[vtable]` attribute. Implementers of the trait will then also have to 112 /// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*` 113 /// associated constant bool for each method in the trait that is set to true if 114 /// the implementer has overridden the associated method. 115 /// 116 /// For a trait method to be optional, it must have a default implementation. 117 /// This is also the case for traits annotated with `#[vtable]`, but in this 118 /// case the default implementation will never be executed. The reason for this 119 /// is that the functions will be called through function pointers installed in 120 /// C side vtables. When an optional method is not implemented on a `#[vtable]` 121 /// trait, a NULL entry is installed in the vtable. Thus the default 122 /// implementation is never called. Since these traits are not designed to be 123 /// used on the Rust side, it should not be possible to call the default 124 /// implementation. This is done to ensure that we call the vtable methods 125 /// through the C vtable, and not through the Rust vtable. Therefore, the 126 /// default implementation should call `kernel::build_error`, which prevents 127 /// calls to this function at compile time: 128 /// 129 /// ```compile_fail 130 /// # // Intentionally missing `use`s to simplify `rusttest`. 131 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 132 /// ``` 133 /// 134 /// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`]. 135 /// 136 /// This macro should not be used when all functions are required. 137 /// 138 /// # Examples 139 /// 140 /// ``` 141 /// use kernel::error::VTABLE_DEFAULT_ERROR; 142 /// use kernel::prelude::*; 143 /// 144 /// // Declares a `#[vtable]` trait 145 /// #[vtable] 146 /// pub trait Operations: Send + Sync + Sized { 147 /// fn foo(&self) -> Result<()> { 148 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 149 /// } 150 /// 151 /// fn bar(&self) -> Result<()> { 152 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 153 /// } 154 /// } 155 /// 156 /// struct Foo; 157 /// 158 /// // Implements the `#[vtable]` trait 159 /// #[vtable] 160 /// impl Operations for Foo { 161 /// fn foo(&self) -> Result<()> { 162 /// # Err(EINVAL) 163 /// // ... 164 /// } 165 /// } 166 /// 167 /// assert_eq!(<Foo as Operations>::HAS_FOO, true); 168 /// assert_eq!(<Foo as Operations>::HAS_BAR, false); 169 /// ``` 170 /// 171 /// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html 172 #[proc_macro_attribute] 173 pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream { 174 vtable::vtable(attr, ts) 175 } 176 177 /// Concatenate two identifiers. 178 /// 179 /// This is useful in macros that need to declare or reference items with names 180 /// starting with a fixed prefix and ending in a user specified name. The resulting 181 /// identifier has the span of the second argument. 182 /// 183 /// # Examples 184 /// 185 /// ``` 186 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 187 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 188 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 189 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 190 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 191 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 192 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 193 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 194 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 195 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 196 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 197 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 198 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 199 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 200 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 201 /// use kernel::macros::concat_idents; 202 /// 203 /// macro_rules! pub_no_prefix { 204 /// ($prefix:ident, $($newname:ident),+) => { 205 /// $(pub(crate) const $newname: u32 = concat_idents!($prefix, $newname);)+ 206 /// }; 207 /// } 208 /// 209 /// pub_no_prefix!( 210 /// binder_driver_return_protocol_, 211 /// BR_OK, 212 /// BR_ERROR, 213 /// BR_TRANSACTION, 214 /// BR_REPLY, 215 /// BR_DEAD_REPLY, 216 /// BR_TRANSACTION_COMPLETE, 217 /// BR_INCREFS, 218 /// BR_ACQUIRE, 219 /// BR_RELEASE, 220 /// BR_DECREFS, 221 /// BR_NOOP, 222 /// BR_SPAWN_LOOPER, 223 /// BR_DEAD_BINDER, 224 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 225 /// BR_FAILED_REPLY 226 /// ); 227 /// 228 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 229 /// ``` 230 #[proc_macro] 231 pub fn concat_idents(ts: TokenStream) -> TokenStream { 232 concat_idents::concat_idents(ts) 233 } 234 235 /// Used to specify the pinning information of the fields of a struct. 236 /// 237 /// This is somewhat similar in purpose as 238 /// [pin-project-lite](https://crates.io/crates/pin-project-lite). 239 /// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each 240 /// field you want to structurally pin. 241 /// 242 /// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`, 243 /// then `#[pin]` directs the type of initializer that is required. 244 /// 245 /// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this 246 /// macro, and change your `Drop` implementation to `PinnedDrop` annotated with 247 /// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care. 248 /// 249 /// # Examples 250 /// 251 /// ``` 252 /// # #![feature(lint_reasons)] 253 /// # use kernel::prelude::*; 254 /// # use std::{sync::Mutex, process::Command}; 255 /// # use kernel::macros::pin_data; 256 /// #[pin_data] 257 /// struct DriverData { 258 /// #[pin] 259 /// queue: Mutex<KVec<Command>>, 260 /// buf: KBox<[u8; 1024 * 1024]>, 261 /// } 262 /// ``` 263 /// 264 /// ``` 265 /// # #![feature(lint_reasons)] 266 /// # use kernel::prelude::*; 267 /// # use std::{sync::Mutex, process::Command}; 268 /// # use core::pin::Pin; 269 /// # pub struct Info; 270 /// # mod bindings { 271 /// # pub unsafe fn destroy_info(_ptr: *mut super::Info) {} 272 /// # } 273 /// use kernel::macros::{pin_data, pinned_drop}; 274 /// 275 /// #[pin_data(PinnedDrop)] 276 /// struct DriverData { 277 /// #[pin] 278 /// queue: Mutex<KVec<Command>>, 279 /// buf: KBox<[u8; 1024 * 1024]>, 280 /// raw_info: *mut Info, 281 /// } 282 /// 283 /// #[pinned_drop] 284 /// impl PinnedDrop for DriverData { 285 /// fn drop(self: Pin<&mut Self>) { 286 /// unsafe { bindings::destroy_info(self.raw_info) }; 287 /// } 288 /// } 289 /// # fn main() {} 290 /// ``` 291 /// 292 /// [`pin_init!`]: ../kernel/macro.pin_init.html 293 // ^ cannot use direct link, since `kernel` is not a dependency of `macros`. 294 #[proc_macro_attribute] 295 pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream { 296 pin_data::pin_data(inner, item) 297 } 298 299 /// Used to implement `PinnedDrop` safely. 300 /// 301 /// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`. 302 /// 303 /// # Examples 304 /// 305 /// ``` 306 /// # #![feature(lint_reasons)] 307 /// # use kernel::prelude::*; 308 /// # use macros::{pin_data, pinned_drop}; 309 /// # use std::{sync::Mutex, process::Command}; 310 /// # use core::pin::Pin; 311 /// # mod bindings { 312 /// # pub struct Info; 313 /// # pub unsafe fn destroy_info(_ptr: *mut Info) {} 314 /// # } 315 /// #[pin_data(PinnedDrop)] 316 /// struct DriverData { 317 /// #[pin] 318 /// queue: Mutex<KVec<Command>>, 319 /// buf: KBox<[u8; 1024 * 1024]>, 320 /// raw_info: *mut bindings::Info, 321 /// } 322 /// 323 /// #[pinned_drop] 324 /// impl PinnedDrop for DriverData { 325 /// fn drop(self: Pin<&mut Self>) { 326 /// unsafe { bindings::destroy_info(self.raw_info) }; 327 /// } 328 /// } 329 /// ``` 330 #[proc_macro_attribute] 331 pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream { 332 pinned_drop::pinned_drop(args, input) 333 } 334 335 /// Paste identifiers together. 336 /// 337 /// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a 338 /// single identifier. 339 /// 340 /// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and 341 /// literals (lifetimes and documentation strings are not supported). There is a difference in 342 /// supported modifiers as well. 343 /// 344 /// # Example 345 /// 346 /// ``` 347 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 348 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 349 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 350 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 351 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 352 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 353 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 354 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 355 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 356 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 357 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 358 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 359 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 360 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 361 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 362 /// macro_rules! pub_no_prefix { 363 /// ($prefix:ident, $($newname:ident),+) => { 364 /// kernel::macros::paste! { 365 /// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+ 366 /// } 367 /// }; 368 /// } 369 /// 370 /// pub_no_prefix!( 371 /// binder_driver_return_protocol_, 372 /// BR_OK, 373 /// BR_ERROR, 374 /// BR_TRANSACTION, 375 /// BR_REPLY, 376 /// BR_DEAD_REPLY, 377 /// BR_TRANSACTION_COMPLETE, 378 /// BR_INCREFS, 379 /// BR_ACQUIRE, 380 /// BR_RELEASE, 381 /// BR_DECREFS, 382 /// BR_NOOP, 383 /// BR_SPAWN_LOOPER, 384 /// BR_DEAD_BINDER, 385 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 386 /// BR_FAILED_REPLY 387 /// ); 388 /// 389 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 390 /// ``` 391 /// 392 /// # Modifiers 393 /// 394 /// For each identifier, it is possible to attach one or multiple modifiers to 395 /// it. 396 /// 397 /// Currently supported modifiers are: 398 /// * `span`: change the span of concatenated identifier to the span of the specified token. By 399 /// default the span of the `[< >]` group is used. 400 /// * `lower`: change the identifier to lower case. 401 /// * `upper`: change the identifier to upper case. 402 /// 403 /// ``` 404 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 405 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 406 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 407 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 408 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 409 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 410 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 411 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 412 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 413 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 414 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 415 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 416 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 417 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 418 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 419 /// macro_rules! pub_no_prefix { 420 /// ($prefix:ident, $($newname:ident),+) => { 421 /// kernel::macros::paste! { 422 /// $(pub(crate) const fn [<$newname:lower:span>]() -> u32 { [<$prefix $newname:span>] })+ 423 /// } 424 /// }; 425 /// } 426 /// 427 /// pub_no_prefix!( 428 /// binder_driver_return_protocol_, 429 /// BR_OK, 430 /// BR_ERROR, 431 /// BR_TRANSACTION, 432 /// BR_REPLY, 433 /// BR_DEAD_REPLY, 434 /// BR_TRANSACTION_COMPLETE, 435 /// BR_INCREFS, 436 /// BR_ACQUIRE, 437 /// BR_RELEASE, 438 /// BR_DECREFS, 439 /// BR_NOOP, 440 /// BR_SPAWN_LOOPER, 441 /// BR_DEAD_BINDER, 442 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 443 /// BR_FAILED_REPLY 444 /// ); 445 /// 446 /// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK); 447 /// ``` 448 /// 449 /// # Literals 450 /// 451 /// Literals can also be concatenated with other identifiers: 452 /// 453 /// ``` 454 /// macro_rules! create_numbered_fn { 455 /// ($name:literal, $val:literal) => { 456 /// kernel::macros::paste! { 457 /// fn [<some_ $name _fn $val>]() -> u32 { $val } 458 /// } 459 /// }; 460 /// } 461 /// 462 /// create_numbered_fn!("foo", 100); 463 /// 464 /// assert_eq!(some_foo_fn100(), 100) 465 /// ``` 466 /// 467 /// [`paste`]: https://docs.rs/paste/ 468 #[proc_macro] 469 pub fn paste(input: TokenStream) -> TokenStream { 470 let mut tokens = input.into_iter().collect(); 471 paste::expand(&mut tokens); 472 tokens.into_iter().collect() 473 } 474 475 /// Derives the [`Zeroable`] trait for the given struct. 476 /// 477 /// This can only be used for structs where every field implements the [`Zeroable`] trait. 478 /// 479 /// # Examples 480 /// 481 /// ``` 482 /// use kernel::macros::Zeroable; 483 /// 484 /// #[derive(Zeroable)] 485 /// pub struct DriverData { 486 /// id: i64, 487 /// buf_ptr: *mut u8, 488 /// len: usize, 489 /// } 490 /// ``` 491 #[proc_macro_derive(Zeroable)] 492 pub fn derive_zeroable(input: TokenStream) -> TokenStream { 493 zeroable::derive(input) 494 } 495