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 // Stable since Rust 1.88.0 under a different name, `proc_macro_span_file`, 13 // which was added in Rust 1.88.0. This is why `cfg_attr` is used here, i.e. 14 // to avoid depending on the full `proc_macro_span` on Rust >= 1.88.0. 15 #![cfg_attr(not(CONFIG_RUSTC_HAS_SPAN_FILE), feature(proc_macro_span))] 16 17 mod concat_idents; 18 mod export; 19 mod fmt; 20 mod for_lt; 21 mod helpers; 22 mod kunit; 23 mod module; 24 mod paste; 25 mod vtable; 26 27 use proc_macro::TokenStream; 28 29 use syn::parse_macro_input; 30 31 /// Declares a kernel module. 32 /// 33 /// The `type` argument should be a type which implements the [`Module`] 34 /// trait. Also accepts various forms of kernel metadata. 35 /// 36 /// The `params` field describe module parameters. Each entry has the form 37 /// 38 /// ```ignore 39 /// parameter_name: type { 40 /// default: default_value, 41 /// description: "Description", 42 /// } 43 /// ``` 44 /// 45 /// `type` may be one of 46 /// 47 /// - [`i8`] 48 /// - [`u8`] 49 /// - [`i8`] 50 /// - [`u8`] 51 /// - [`i16`] 52 /// - [`u16`] 53 /// - [`i32`] 54 /// - [`u32`] 55 /// - [`i64`] 56 /// - [`u64`] 57 /// - [`isize`] 58 /// - [`usize`] 59 /// 60 /// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h) 61 /// 62 /// [`Module`]: ../kernel/trait.Module.html 63 /// 64 /// # Examples 65 /// 66 /// ```ignore 67 /// use kernel::prelude::*; 68 /// 69 /// module!{ 70 /// type: MyModule, 71 /// name: "my_kernel_module", 72 /// authors: ["Rust for Linux Contributors"], 73 /// description: "My very own kernel module!", 74 /// license: "GPL", 75 /// alias: ["alternate_module_name"], 76 /// params: { 77 /// my_parameter: i64 { 78 /// default: 1, 79 /// description: "This parameter has a default of 1", 80 /// }, 81 /// }, 82 /// } 83 /// 84 /// struct MyModule(i32); 85 /// 86 /// impl kernel::Module for MyModule { 87 /// fn init(_module: &'static ThisModule) -> Result<Self> { 88 /// let foo: i32 = 42; 89 /// pr_info!("I contain: {}\n", foo); 90 /// pr_info!("i32 param is: {}\n", module_parameters::my_parameter.read()); 91 /// Ok(Self(foo)) 92 /// } 93 /// } 94 /// # fn main() {} 95 /// ``` 96 /// 97 /// ## Firmware 98 /// 99 /// The following example shows how to declare a kernel module that needs 100 /// to load binary firmware files. You need to specify the file names of 101 /// the firmware in the `firmware` field. The information is embedded 102 /// in the `modinfo` section of the kernel module. For example, a tool to 103 /// build an initramfs uses this information to put the firmware files into 104 /// the initramfs image. 105 /// 106 /// ``` 107 /// use kernel::prelude::*; 108 /// 109 /// module!{ 110 /// type: MyDeviceDriverModule, 111 /// name: "my_device_driver_module", 112 /// authors: ["Rust for Linux Contributors"], 113 /// description: "My device driver requires firmware", 114 /// license: "GPL", 115 /// firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"], 116 /// } 117 /// 118 /// struct MyDeviceDriverModule; 119 /// 120 /// impl kernel::Module for MyDeviceDriverModule { 121 /// fn init(_module: &'static ThisModule) -> Result<Self> { 122 /// Ok(Self) 123 /// } 124 /// } 125 /// # fn main() {} 126 /// ``` 127 /// 128 /// # Supported argument types 129 /// - `type`: type which implements the [`Module`] trait (required). 130 /// - `name`: ASCII string literal of the name of the kernel module (required). 131 /// - `authors`: array of ASCII string literals of the authors of the kernel module. 132 /// - `description`: string literal of the description of the kernel module. 133 /// - `license`: ASCII string literal of the license of the kernel module (required). 134 /// - `alias`: array of ASCII string literals of the alias names of the kernel module. 135 /// - `firmware`: array of ASCII string literals of the firmware files of 136 /// the kernel module. 137 #[proc_macro] 138 pub fn module(input: TokenStream) -> TokenStream { 139 module::module(parse_macro_input!(input)) 140 .unwrap_or_else(|e| e.into_compile_error()) 141 .into() 142 } 143 144 /// Declares or implements a vtable trait. 145 /// 146 /// Linux's use of pure vtables is very close to Rust traits, but they differ 147 /// in how unimplemented functions are represented. In Rust, traits can provide 148 /// default implementation for all non-required methods (and the default 149 /// implementation could just return `Error::EINVAL`); Linux typically use C 150 /// `NULL` pointers to represent these functions. 151 /// 152 /// This attribute closes that gap. A trait can be annotated with the 153 /// `#[vtable]` attribute. Implementers of the trait will then also have to 154 /// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*` 155 /// associated constant bool for each method in the trait that is set to true if 156 /// the implementer has overridden the associated method. 157 /// 158 /// For a trait method to be optional, it must have a default implementation. 159 /// This is also the case for traits annotated with `#[vtable]`, but in this 160 /// case the default implementation will never be executed. The reason for this 161 /// is that the functions will be called through function pointers installed in 162 /// C side vtables. When an optional method is not implemented on a `#[vtable]` 163 /// trait, a `NULL` entry is installed in the vtable. Thus the default 164 /// implementation is never called. Since these traits are not designed to be 165 /// used on the Rust side, it should not be possible to call the default 166 /// implementation. This is done to ensure that we call the vtable methods 167 /// through the C vtable, and not through the Rust vtable. Therefore, the 168 /// default implementation should call `build_error!`, which prevents 169 /// calls to this function at compile time: 170 /// 171 /// ```compile_fail 172 /// # // Intentionally missing `use`s to simplify `rusttest`. 173 /// build_error!(VTABLE_DEFAULT_ERROR) 174 /// ``` 175 /// 176 /// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`]. 177 /// 178 /// This macro should not be used when all functions are required. 179 /// 180 /// Additionally, this macro automatically handles the `OwnerModule` 181 /// associated type: on the trait side, `type OwnerModule: ModuleMetadata;` 182 /// is added as a required associated type if not already defined; on the 183 /// impl side, `type OwnerModule = LocalModule;` is automatically inserted 184 /// if not explicitly defined. 185 /// 186 /// # Examples 187 /// 188 /// ``` 189 /// use kernel::error::VTABLE_DEFAULT_ERROR; 190 /// use kernel::prelude::*; 191 /// 192 /// # struct LocalModule; 193 /// # impl kernel::ModuleMetadata for LocalModule { 194 /// # const NAME: &'static kernel::str::CStr = c"vtable_doctest"; 195 /// # 196 /// # // SAFETY: This doctest runs on the host: there is no `THIS_MODULE`. 197 /// # const THIS_MODULE: kernel::ThisModule = unsafe { 198 /// # kernel::ThisModule::from_ptr(core::ptr::null_mut()) 199 /// # }; 200 /// # } 201 /// # 202 /// # fn main() { 203 /// // Declares a `#[vtable]` trait 204 /// #[vtable] 205 /// pub trait Operations: Send + Sync + Sized { 206 /// fn foo(&self) -> Result<()> { 207 /// build_error!(VTABLE_DEFAULT_ERROR) 208 /// } 209 /// 210 /// fn bar(&self) -> Result<()> { 211 /// build_error!(VTABLE_DEFAULT_ERROR) 212 /// } 213 /// } 214 /// 215 /// struct Foo; 216 /// 217 /// // Implements the `#[vtable]` trait 218 /// #[vtable] 219 /// impl Operations for Foo { 220 /// fn foo(&self) -> Result<()> { 221 /// # Err(EINVAL) 222 /// // ... 223 /// } 224 /// } 225 /// 226 /// assert_eq!(<Foo as Operations>::HAS_FOO, true); 227 /// assert_eq!(<Foo as Operations>::HAS_BAR, false); 228 /// # } 229 /// ``` 230 /// 231 /// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html 232 #[proc_macro_attribute] 233 pub fn vtable(attr: TokenStream, input: TokenStream) -> TokenStream { 234 parse_macro_input!(attr as syn::parse::Nothing); 235 vtable::vtable(parse_macro_input!(input)) 236 .unwrap_or_else(|e| e.into_compile_error()) 237 .into() 238 } 239 240 /// Export a function so that C code can call it via a header file. 241 /// 242 /// Functions exported using this macro can be called from C code using the declaration in the 243 /// appropriate header file. It should only be used in cases where C calls the function through a 244 /// header file; cases where C calls into Rust via a function pointer in a vtable (such as 245 /// `file_operations`) should not use this macro. 246 /// 247 /// This macro has the following effect: 248 /// 249 /// * Disables name mangling for this function. 250 /// * Verifies at compile-time that the function signature matches the declaration in the header 251 /// file. 252 /// 253 /// You must declare the signature of the Rust function in a header file that is included by 254 /// `rust/bindings/bindings_helper.h`. 255 /// 256 /// This macro is *not* the same as the C macros `EXPORT_SYMBOL_*`. All Rust symbols are currently 257 /// automatically exported with `EXPORT_SYMBOL_GPL`. 258 #[proc_macro_attribute] 259 pub fn export(attr: TokenStream, input: TokenStream) -> TokenStream { 260 parse_macro_input!(attr as syn::parse::Nothing); 261 export::export(parse_macro_input!(input)).into() 262 } 263 264 /// Like [`core::format_args!`], but automatically wraps arguments in [`kernel::fmt::Adapter`]. 265 /// 266 /// This macro allows generating `fmt::Arguments` while ensuring that each argument is wrapped with 267 /// `::kernel::fmt::Adapter`, which customizes formatting behavior for kernel logging. 268 /// 269 /// Named arguments used in the format string (e.g. `{foo}`) are detected and resolved from local 270 /// bindings. All positional and named arguments are automatically wrapped. 271 /// 272 /// This macro is an implementation detail of other kernel logging macros like [`pr_info!`] and 273 /// should not typically be used directly. 274 /// 275 /// [`kernel::fmt::Adapter`]: ../kernel/fmt/struct.Adapter.html 276 /// [`pr_info!`]: ../kernel/macro.pr_info.html 277 #[proc_macro] 278 pub fn fmt(input: TokenStream) -> TokenStream { 279 fmt::fmt(input.into()).into() 280 } 281 282 /// Concatenate two identifiers. 283 /// 284 /// This is useful in macros that need to declare or reference items with names 285 /// starting with a fixed prefix and ending in a user specified name. The resulting 286 /// identifier has the span of the second argument. 287 /// 288 /// # Examples 289 /// 290 /// ``` 291 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 292 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 293 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 294 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 295 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 296 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 297 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 298 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 299 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 300 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 301 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 302 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 303 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 304 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 305 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 306 /// use kernel::macros::concat_idents; 307 /// 308 /// macro_rules! pub_no_prefix { 309 /// ($prefix:ident, $($newname:ident),+) => { 310 /// $(pub(crate) const $newname: u32 = concat_idents!($prefix, $newname);)+ 311 /// }; 312 /// } 313 /// 314 /// pub_no_prefix!( 315 /// binder_driver_return_protocol_, 316 /// BR_OK, 317 /// BR_ERROR, 318 /// BR_TRANSACTION, 319 /// BR_REPLY, 320 /// BR_DEAD_REPLY, 321 /// BR_TRANSACTION_COMPLETE, 322 /// BR_INCREFS, 323 /// BR_ACQUIRE, 324 /// BR_RELEASE, 325 /// BR_DECREFS, 326 /// BR_NOOP, 327 /// BR_SPAWN_LOOPER, 328 /// BR_DEAD_BINDER, 329 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 330 /// BR_FAILED_REPLY 331 /// ); 332 /// 333 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 334 /// ``` 335 #[proc_macro] 336 pub fn concat_idents(input: TokenStream) -> TokenStream { 337 concat_idents::concat_idents(parse_macro_input!(input)).into() 338 } 339 340 /// Paste identifiers together. 341 /// 342 /// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a 343 /// single identifier. 344 /// 345 /// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and 346 /// literals (lifetimes and documentation strings are not supported). There is a difference in 347 /// supported modifiers as well. 348 /// 349 /// # Examples 350 /// 351 /// ``` 352 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 353 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 354 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 355 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 356 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 357 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 358 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 359 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 360 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 361 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 362 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 363 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 364 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 365 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 366 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 367 /// macro_rules! pub_no_prefix { 368 /// ($prefix:ident, $($newname:ident),+) => { 369 /// ::kernel::macros::paste! { 370 /// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+ 371 /// } 372 /// }; 373 /// } 374 /// 375 /// pub_no_prefix!( 376 /// binder_driver_return_protocol_, 377 /// BR_OK, 378 /// BR_ERROR, 379 /// BR_TRANSACTION, 380 /// BR_REPLY, 381 /// BR_DEAD_REPLY, 382 /// BR_TRANSACTION_COMPLETE, 383 /// BR_INCREFS, 384 /// BR_ACQUIRE, 385 /// BR_RELEASE, 386 /// BR_DECREFS, 387 /// BR_NOOP, 388 /// BR_SPAWN_LOOPER, 389 /// BR_DEAD_BINDER, 390 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 391 /// BR_FAILED_REPLY 392 /// ); 393 /// 394 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 395 /// ``` 396 /// 397 /// # Modifiers 398 /// 399 /// For each identifier, it is possible to attach one or multiple modifiers to 400 /// it. 401 /// 402 /// Currently supported modifiers are: 403 /// * `span`: change the span of concatenated identifier to the span of the specified token. By 404 /// default the span of the `[< >]` group is used. 405 /// * `lower`: change the identifier to lower case. 406 /// * `upper`: change the identifier to upper case. 407 /// 408 /// ``` 409 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 410 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 411 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 412 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 413 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 414 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 415 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 416 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 417 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 418 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 419 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 420 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 421 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 422 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 423 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 424 /// macro_rules! pub_no_prefix { 425 /// ($prefix:ident, $($newname:ident),+) => { 426 /// ::kernel::macros::paste! { 427 /// $(pub(crate) const fn [<$newname:lower:span>]() -> u32 { [<$prefix $newname:span>] })+ 428 /// } 429 /// }; 430 /// } 431 /// 432 /// pub_no_prefix!( 433 /// binder_driver_return_protocol_, 434 /// BR_OK, 435 /// BR_ERROR, 436 /// BR_TRANSACTION, 437 /// BR_REPLY, 438 /// BR_DEAD_REPLY, 439 /// BR_TRANSACTION_COMPLETE, 440 /// BR_INCREFS, 441 /// BR_ACQUIRE, 442 /// BR_RELEASE, 443 /// BR_DECREFS, 444 /// BR_NOOP, 445 /// BR_SPAWN_LOOPER, 446 /// BR_DEAD_BINDER, 447 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 448 /// BR_FAILED_REPLY 449 /// ); 450 /// 451 /// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK); 452 /// ``` 453 /// 454 /// # Literals 455 /// 456 /// Literals can also be concatenated with other identifiers: 457 /// 458 /// ``` 459 /// macro_rules! create_numbered_fn { 460 /// ($name:literal, $val:literal) => { 461 /// ::kernel::macros::paste! { 462 /// fn [<some_ $name _fn $val>]() -> u32 { $val } 463 /// } 464 /// }; 465 /// } 466 /// 467 /// create_numbered_fn!("foo", 100); 468 /// 469 /// assert_eq!(some_foo_fn100(), 100) 470 /// ``` 471 /// 472 /// [`paste`]: https://docs.rs/paste/ 473 #[proc_macro] 474 pub fn paste(input: TokenStream) -> TokenStream { 475 let mut tokens = proc_macro2::TokenStream::from(input).into_iter().collect(); 476 paste::expand(&mut tokens); 477 tokens 478 .into_iter() 479 .collect::<proc_macro2::TokenStream>() 480 .into() 481 } 482 483 /// Registers a KUnit test suite and its test cases using a user-space like syntax. 484 /// 485 /// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module 486 /// is ignored. 487 /// 488 /// # Examples 489 /// 490 /// ```ignore 491 /// # use kernel::prelude::*; 492 /// #[kunit_tests(kunit_test_suit_name)] 493 /// mod tests { 494 /// #[test] 495 /// fn foo() { 496 /// assert_eq!(1, 1); 497 /// } 498 /// 499 /// #[test] 500 /// fn bar() { 501 /// assert_eq!(2, 2); 502 /// } 503 /// } 504 /// ``` 505 #[proc_macro_attribute] 506 pub fn kunit_tests(attr: TokenStream, input: TokenStream) -> TokenStream { 507 kunit::kunit_tests(parse_macro_input!(attr), parse_macro_input!(input)) 508 .unwrap_or_else(|e| e.into_compile_error()) 509 .into() 510 } 511 512 /// Obtain a type that implements [`ForLt`] for the given higher-ranked type. 513 /// 514 /// Please refer to the documentation of the [`ForLt`] trait. 515 /// 516 /// [`ForLt`]: trait.ForLt.html 517 #[proc_macro] 518 // The macro shares the name with the trait. 519 #[allow(non_snake_case)] 520 pub fn ForLt(input: TokenStream) -> TokenStream { 521 for_lt::for_lt(parse_macro_input!(input)).into() 522 } 523