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 // Stable since Rust 1.87.0. 10 #![feature(extract_if)] 11 12 mod concat_idents; 13 mod export; 14 mod fmt; 15 mod for_lt; 16 mod helpers; 17 mod kunit; 18 mod module; 19 mod paste; 20 mod vtable; 21 22 use proc_macro::TokenStream; 23 24 use syn::parse_macro_input; 25 26 /// Declares a kernel module. 27 /// 28 /// The `type` argument should be a type which implements the [`Module`] 29 /// trait. Also accepts various forms of kernel metadata. 30 /// 31 /// The `params` field describe module parameters. Each entry has the form 32 /// 33 /// ```ignore 34 /// parameter_name: type { 35 /// default: default_value, 36 /// description: "Description", 37 /// } 38 /// ``` 39 /// 40 /// `type` may be one of 41 /// 42 /// - [`i8`] 43 /// - [`u8`] 44 /// - [`i8`] 45 /// - [`u8`] 46 /// - [`i16`] 47 /// - [`u16`] 48 /// - [`i32`] 49 /// - [`u32`] 50 /// - [`i64`] 51 /// - [`u64`] 52 /// - [`isize`] 53 /// - [`usize`] 54 /// - [`bool`] 55 /// 56 /// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h) 57 /// 58 /// [`Module`]: ../kernel/trait.Module.html 59 /// 60 /// # Examples 61 /// 62 /// ```ignore 63 /// use kernel::prelude::*; 64 /// 65 /// module!{ 66 /// type: MyModule, 67 /// name: "my_kernel_module", 68 /// authors: ["Rust for Linux Contributors"], 69 /// description: "My very own kernel module!", 70 /// license: "GPL", 71 /// alias: ["alternate_module_name"], 72 /// params: { 73 /// my_parameter: i64 { 74 /// default: 1, 75 /// description: "This parameter has a default of 1", 76 /// }, 77 /// }, 78 /// } 79 /// 80 /// struct MyModule(i32); 81 /// 82 /// impl kernel::Module for MyModule { 83 /// fn init(_module: &'static ThisModule) -> Result<Self> { 84 /// let foo: i32 = 42; 85 /// pr_info!("I contain: {}\n", foo); 86 /// pr_info!("i32 param is: {}\n", module_parameters::my_parameter.read()); 87 /// Ok(Self(foo)) 88 /// } 89 /// } 90 /// # fn main() {} 91 /// ``` 92 /// 93 /// ## Firmware 94 /// 95 /// The following example shows how to declare a kernel module that needs 96 /// to load binary firmware files. You need to specify the file names of 97 /// the firmware in the `firmware` field. The information is embedded 98 /// in the `modinfo` section of the kernel module. For example, a tool to 99 /// build an initramfs uses this information to put the firmware files into 100 /// the initramfs image. 101 /// 102 /// ``` 103 /// use kernel::prelude::*; 104 /// 105 /// module!{ 106 /// type: MyDeviceDriverModule, 107 /// name: "my_device_driver_module", 108 /// authors: ["Rust for Linux Contributors"], 109 /// description: "My device driver requires firmware", 110 /// license: "GPL", 111 /// firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"], 112 /// } 113 /// 114 /// struct MyDeviceDriverModule; 115 /// 116 /// impl kernel::Module for MyDeviceDriverModule { 117 /// fn init(_module: &'static ThisModule) -> Result<Self> { 118 /// Ok(Self) 119 /// } 120 /// } 121 /// # fn main() {} 122 /// ``` 123 /// 124 /// # Supported argument types 125 /// - `type`: type which implements the [`Module`] trait (required). 126 /// - `name`: ASCII string literal of the name of the kernel module (required). 127 /// - `authors`: array of string literals of the authors of the kernel module. 128 /// - `description`: string literal of the description of the kernel module. 129 /// - `license`: ASCII string literal of the license of the kernel module (required). 130 /// - `alias`: array of ASCII string literals of the alias names of the kernel module. 131 /// - `firmware`: array of ASCII string literals of the firmware files of 132 /// the kernel module. 133 #[proc_macro] 134 pub fn module(input: TokenStream) -> TokenStream { 135 module::module(parse_macro_input!(input)) 136 .unwrap_or_else(|e| e.into_compile_error()) 137 .into() 138 } 139 140 /// Declares or implements a vtable trait. 141 /// 142 /// Linux's use of pure vtables is very close to Rust traits, but they differ 143 /// in how unimplemented functions are represented. In Rust, traits can provide 144 /// default implementation for all non-required methods (and the default 145 /// implementation could just return `Error::EINVAL`); Linux typically use C 146 /// `NULL` pointers to represent these functions. 147 /// 148 /// This attribute closes that gap. A trait can be annotated with the 149 /// `#[vtable]` attribute. Implementers of the trait will then also have to 150 /// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*` 151 /// associated constant bool for each method in the trait that is set to true if 152 /// the implementer has overridden the associated method. 153 /// 154 /// For a trait method to be optional for normal traits, it must have a default 155 /// implementation. However, for many users of `#[vtable]`, the functions will 156 /// be called through function pointers installed in C side vtables. When an 157 /// optional method is not implemented on a `#[vtable]` trait, a `NULL` entry is 158 /// installed in the vtable; thus the default implementation is never called. If 159 /// this is the case, `#[optional]` can be applied on the optional method. 160 /// Methods annotated as such do not need to be implemented nor need a default 161 /// implementation. Calling these methods on types that do not implement them 162 /// will fail to build using the `build_error!` mechanism. 163 /// 164 /// This macro should not be used when all functions are required. 165 /// 166 /// Additionally, this macro automatically handles the `OwnerModule` 167 /// associated type: on the trait side, `type OwnerModule: ModuleMetadata;` 168 /// is added as a required associated type if not already defined; on the 169 /// impl side, `type OwnerModule = LocalModule;` is automatically inserted 170 /// if not explicitly defined. 171 /// 172 /// # Examples 173 /// 174 /// ``` 175 /// use kernel::prelude::*; 176 /// 177 /// # struct LocalModule; 178 /// # impl kernel::ModuleMetadata for LocalModule { 179 /// # const NAME: &'static kernel::str::CStr = c"vtable_doctest"; 180 /// # 181 /// # // SAFETY: This doctest runs on the host: there is no `THIS_MODULE`. 182 /// # const THIS_MODULE: kernel::ThisModule = unsafe { 183 /// # kernel::ThisModule::from_ptr(core::ptr::null_mut()) 184 /// # }; 185 /// # } 186 /// # 187 /// # fn main() { 188 /// // Declares a `#[vtable]` trait 189 /// #[vtable] 190 /// pub trait Operations: Send + Sync + Sized { 191 /// #[optional] 192 /// fn foo(&self) -> Result<()>; 193 /// 194 /// #[optional] 195 /// fn bar(&self) -> Result<()>; 196 /// } 197 /// 198 /// struct Foo; 199 /// 200 /// // Implements the `#[vtable]` trait 201 /// #[vtable] 202 /// impl Operations for Foo { 203 /// fn foo(&self) -> Result<()> { 204 /// # Err(EINVAL) 205 /// // ... 206 /// } 207 /// } 208 /// 209 /// assert_eq!(<Foo as Operations>::HAS_FOO, true); 210 /// assert_eq!(<Foo as Operations>::HAS_BAR, false); 211 /// # } 212 /// ``` 213 #[proc_macro_attribute] 214 pub fn vtable(attr: TokenStream, input: TokenStream) -> TokenStream { 215 parse_macro_input!(attr as syn::parse::Nothing); 216 vtable::vtable(parse_macro_input!(input)) 217 .unwrap_or_else(|e| e.into_compile_error()) 218 .into() 219 } 220 221 /// Export a function so that C code can call it via a header file. 222 /// 223 /// Functions exported using this macro can be called from C code using the declaration in the 224 /// appropriate header file. It should only be used in cases where C calls the function through a 225 /// header file; cases where C calls into Rust via a function pointer in a vtable (such as 226 /// `file_operations`) should not use this macro. 227 /// 228 /// This macro has the following effect: 229 /// 230 /// * Disables name mangling for this function. 231 /// * Verifies at compile-time that the function signature matches the declaration in the header 232 /// file. 233 /// 234 /// You must declare the signature of the Rust function in a header file that is included by 235 /// `rust/bindings/bindings_helper.h`. 236 /// 237 /// This macro is *not* the same as the C macros `EXPORT_SYMBOL_*`. All Rust symbols are currently 238 /// automatically exported with `EXPORT_SYMBOL_GPL`. 239 #[proc_macro_attribute] 240 pub fn export(attr: TokenStream, input: TokenStream) -> TokenStream { 241 parse_macro_input!(attr as syn::parse::Nothing); 242 export::export(parse_macro_input!(input)).into() 243 } 244 245 /// Like [`core::format_args!`], but automatically wraps arguments in [`kernel::fmt::Adapter`]. 246 /// 247 /// This macro allows generating `fmt::Arguments` while ensuring that each argument is wrapped with 248 /// `::kernel::fmt::Adapter`, which customizes formatting behavior for kernel logging. 249 /// 250 /// Named arguments used in the format string (e.g. `{foo}`) are detected and resolved from local 251 /// bindings. All positional and named arguments are automatically wrapped. 252 /// 253 /// This macro is an implementation detail of other kernel logging macros like [`pr_info!`] and 254 /// should not typically be used directly. 255 /// 256 /// [`kernel::fmt::Adapter`]: ../kernel/fmt/struct.Adapter.html 257 /// [`pr_info!`]: ../kernel/macro.pr_info.html 258 #[proc_macro] 259 pub fn fmt(input: TokenStream) -> TokenStream { 260 fmt::fmt(input.into()).into() 261 } 262 263 /// Concatenate two identifiers. 264 /// 265 /// This is useful in macros that need to declare or reference items with names 266 /// starting with a fixed prefix and ending in a user specified name. The resulting 267 /// identifier has the span of the second argument. 268 /// 269 /// # Examples 270 /// 271 /// ``` 272 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 273 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 274 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 275 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 276 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 277 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 278 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 279 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 280 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 281 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 282 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 283 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 284 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 285 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 286 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 287 /// use kernel::macros::concat_idents; 288 /// 289 /// macro_rules! pub_no_prefix { 290 /// ($prefix:ident, $($newname:ident),+) => { 291 /// $(pub(crate) const $newname: u32 = concat_idents!($prefix, $newname);)+ 292 /// }; 293 /// } 294 /// 295 /// pub_no_prefix!( 296 /// binder_driver_return_protocol_, 297 /// BR_OK, 298 /// BR_ERROR, 299 /// BR_TRANSACTION, 300 /// BR_REPLY, 301 /// BR_DEAD_REPLY, 302 /// BR_TRANSACTION_COMPLETE, 303 /// BR_INCREFS, 304 /// BR_ACQUIRE, 305 /// BR_RELEASE, 306 /// BR_DECREFS, 307 /// BR_NOOP, 308 /// BR_SPAWN_LOOPER, 309 /// BR_DEAD_BINDER, 310 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 311 /// BR_FAILED_REPLY 312 /// ); 313 /// 314 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 315 /// ``` 316 #[proc_macro] 317 pub fn concat_idents(input: TokenStream) -> TokenStream { 318 concat_idents::concat_idents(parse_macro_input!(input)).into() 319 } 320 321 /// Paste identifiers together. 322 /// 323 /// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a 324 /// single identifier. 325 /// 326 /// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and 327 /// literals (lifetimes and documentation strings are not supported). There is a difference in 328 /// supported modifiers as well. 329 /// 330 /// # Examples 331 /// 332 /// ``` 333 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 334 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 335 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 336 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 337 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 338 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 339 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 340 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 341 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 342 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 343 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 344 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 345 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 346 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 347 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 348 /// macro_rules! pub_no_prefix { 349 /// ($prefix:ident, $($newname:ident),+) => { 350 /// ::kernel::macros::paste! { 351 /// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+ 352 /// } 353 /// }; 354 /// } 355 /// 356 /// pub_no_prefix!( 357 /// binder_driver_return_protocol_, 358 /// BR_OK, 359 /// BR_ERROR, 360 /// BR_TRANSACTION, 361 /// BR_REPLY, 362 /// BR_DEAD_REPLY, 363 /// BR_TRANSACTION_COMPLETE, 364 /// BR_INCREFS, 365 /// BR_ACQUIRE, 366 /// BR_RELEASE, 367 /// BR_DECREFS, 368 /// BR_NOOP, 369 /// BR_SPAWN_LOOPER, 370 /// BR_DEAD_BINDER, 371 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 372 /// BR_FAILED_REPLY 373 /// ); 374 /// 375 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 376 /// ``` 377 /// 378 /// # Modifiers 379 /// 380 /// For each identifier, it is possible to attach one or multiple modifiers to 381 /// it. 382 /// 383 /// Currently supported modifiers are: 384 /// * `span`: change the span of concatenated identifier to the span of the specified token. By 385 /// default the span of the `[< >]` group is used. 386 /// * `lower`: change the identifier to lower case. 387 /// * `upper`: change the identifier to upper case. 388 /// 389 /// ``` 390 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 391 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 392 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 393 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 394 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 395 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 396 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 397 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 398 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 399 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 400 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 401 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 402 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 403 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 404 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 405 /// macro_rules! pub_no_prefix { 406 /// ($prefix:ident, $($newname:ident),+) => { 407 /// ::kernel::macros::paste! { 408 /// $(pub(crate) const fn [<$newname:lower:span>]() -> u32 { [<$prefix $newname:span>] })+ 409 /// } 410 /// }; 411 /// } 412 /// 413 /// pub_no_prefix!( 414 /// binder_driver_return_protocol_, 415 /// BR_OK, 416 /// BR_ERROR, 417 /// BR_TRANSACTION, 418 /// BR_REPLY, 419 /// BR_DEAD_REPLY, 420 /// BR_TRANSACTION_COMPLETE, 421 /// BR_INCREFS, 422 /// BR_ACQUIRE, 423 /// BR_RELEASE, 424 /// BR_DECREFS, 425 /// BR_NOOP, 426 /// BR_SPAWN_LOOPER, 427 /// BR_DEAD_BINDER, 428 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 429 /// BR_FAILED_REPLY 430 /// ); 431 /// 432 /// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK); 433 /// ``` 434 /// 435 /// # Literals 436 /// 437 /// Literals can also be concatenated with other identifiers: 438 /// 439 /// ``` 440 /// macro_rules! create_numbered_fn { 441 /// ($name:literal, $val:literal) => { 442 /// ::kernel::macros::paste! { 443 /// fn [<some_ $name _fn $val>]() -> u32 { $val } 444 /// } 445 /// }; 446 /// } 447 /// 448 /// create_numbered_fn!("foo", 100); 449 /// 450 /// assert_eq!(some_foo_fn100(), 100) 451 /// ``` 452 /// 453 /// [`paste`]: https://docs.rs/paste/ 454 #[proc_macro] 455 pub fn paste(input: TokenStream) -> TokenStream { 456 let mut tokens = proc_macro2::TokenStream::from(input).into_iter().collect(); 457 paste::expand(&mut tokens); 458 tokens 459 .into_iter() 460 .collect::<proc_macro2::TokenStream>() 461 .into() 462 } 463 464 /// Registers a KUnit test suite and its test cases using a user-space like syntax. 465 /// 466 /// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module 467 /// is ignored. 468 /// 469 /// # Examples 470 /// 471 /// ```ignore 472 /// # use kernel::prelude::*; 473 /// #[kunit_tests(kunit_test_suit_name)] 474 /// mod tests { 475 /// #[test] 476 /// fn foo() { 477 /// assert_eq!(1, 1); 478 /// } 479 /// 480 /// #[test] 481 /// fn bar() { 482 /// assert_eq!(2, 2); 483 /// } 484 /// } 485 /// ``` 486 #[proc_macro_attribute] 487 pub fn kunit_tests(attr: TokenStream, input: TokenStream) -> TokenStream { 488 kunit::kunit_tests(parse_macro_input!(attr), parse_macro_input!(input)) 489 .unwrap_or_else(|e| e.into_compile_error()) 490 .into() 491 } 492 493 /// Obtain a type that implements [`ForLt`] for the given higher-ranked type. 494 /// 495 /// Please refer to the documentation of the [`ForLt`] trait. 496 /// 497 /// [`ForLt`]: trait.ForLt.html 498 #[proc_macro] 499 #[allow(non_snake_case)] 500 pub fn ForLt(input: TokenStream) -> TokenStream { 501 for_lt::for_lt(parse_macro_input!(input)).into() 502 } 503 504 /// Obtain a type that implements [`CovariantForLt`] (and [`ForLt`]) for the given higher-ranked 505 /// type. 506 /// 507 /// Unlike [`ForLt!`], this macro additionally proves that the type is covariant over the lifetime, 508 /// providing a safe [`CovariantForLt::cast_ref`] method. 509 /// 510 /// Please refer to the documentation of the [`CovariantForLt`] trait. 511 /// 512 /// [`CovariantForLt`]: trait.CovariantForLt.html 513 /// [`CovariantForLt::cast_ref`]: trait.CovariantForLt.html#method.cast_ref 514 /// [`ForLt`]: trait.ForLt.html 515 #[proc_macro] 516 #[allow(non_snake_case)] 517 pub fn CovariantForLt(input: TokenStream) -> TokenStream { 518 for_lt::covariant_for_lt(parse_macro_input!(input)).into() 519 } 520