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 /// - [`bool`] 60 /// 61 /// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h) 62 /// 63 /// [`Module`]: ../kernel/trait.Module.html 64 /// 65 /// # Examples 66 /// 67 /// ```ignore 68 /// use kernel::prelude::*; 69 /// 70 /// module!{ 71 /// type: MyModule, 72 /// name: "my_kernel_module", 73 /// authors: ["Rust for Linux Contributors"], 74 /// description: "My very own kernel module!", 75 /// license: "GPL", 76 /// alias: ["alternate_module_name"], 77 /// params: { 78 /// my_parameter: i64 { 79 /// default: 1, 80 /// description: "This parameter has a default of 1", 81 /// }, 82 /// }, 83 /// } 84 /// 85 /// struct MyModule(i32); 86 /// 87 /// impl kernel::Module for MyModule { 88 /// fn init(_module: &'static ThisModule) -> Result<Self> { 89 /// let foo: i32 = 42; 90 /// pr_info!("I contain: {}\n", foo); 91 /// pr_info!("i32 param is: {}\n", module_parameters::my_parameter.read()); 92 /// Ok(Self(foo)) 93 /// } 94 /// } 95 /// # fn main() {} 96 /// ``` 97 /// 98 /// ## Firmware 99 /// 100 /// The following example shows how to declare a kernel module that needs 101 /// to load binary firmware files. You need to specify the file names of 102 /// the firmware in the `firmware` field. The information is embedded 103 /// in the `modinfo` section of the kernel module. For example, a tool to 104 /// build an initramfs uses this information to put the firmware files into 105 /// the initramfs image. 106 /// 107 /// ``` 108 /// use kernel::prelude::*; 109 /// 110 /// module!{ 111 /// type: MyDeviceDriverModule, 112 /// name: "my_device_driver_module", 113 /// authors: ["Rust for Linux Contributors"], 114 /// description: "My device driver requires firmware", 115 /// license: "GPL", 116 /// firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"], 117 /// } 118 /// 119 /// struct MyDeviceDriverModule; 120 /// 121 /// impl kernel::Module for MyDeviceDriverModule { 122 /// fn init(_module: &'static ThisModule) -> Result<Self> { 123 /// Ok(Self) 124 /// } 125 /// } 126 /// # fn main() {} 127 /// ``` 128 /// 129 /// # Supported argument types 130 /// - `type`: type which implements the [`Module`] trait (required). 131 /// - `name`: ASCII string literal of the name of the kernel module (required). 132 /// - `authors`: array of ASCII string literals of the authors of the kernel module. 133 /// - `description`: string literal of the description of the kernel module. 134 /// - `license`: ASCII string literal of the license of the kernel module (required). 135 /// - `alias`: array of ASCII string literals of the alias names of the kernel module. 136 /// - `firmware`: array of ASCII string literals of the firmware files of 137 /// the kernel module. 138 #[proc_macro] 139 pub fn module(input: TokenStream) -> TokenStream { 140 module::module(parse_macro_input!(input)) 141 .unwrap_or_else(|e| e.into_compile_error()) 142 .into() 143 } 144 145 /// Declares or implements a vtable trait. 146 /// 147 /// Linux's use of pure vtables is very close to Rust traits, but they differ 148 /// in how unimplemented functions are represented. In Rust, traits can provide 149 /// default implementation for all non-required methods (and the default 150 /// implementation could just return `Error::EINVAL`); Linux typically use C 151 /// `NULL` pointers to represent these functions. 152 /// 153 /// This attribute closes that gap. A trait can be annotated with the 154 /// `#[vtable]` attribute. Implementers of the trait will then also have to 155 /// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*` 156 /// associated constant bool for each method in the trait that is set to true if 157 /// the implementer has overridden the associated method. 158 /// 159 /// For a trait method to be optional, it must have a default implementation. 160 /// This is also the case for traits annotated with `#[vtable]`, but in this 161 /// case the default implementation will never be executed. The reason for this 162 /// is that the functions will be called through function pointers installed in 163 /// C side vtables. When an optional method is not implemented on a `#[vtable]` 164 /// trait, a `NULL` entry is installed in the vtable. Thus the default 165 /// implementation is never called. Since these traits are not designed to be 166 /// used on the Rust side, it should not be possible to call the default 167 /// implementation. This is done to ensure that we call the vtable methods 168 /// through the C vtable, and not through the Rust vtable. Therefore, the 169 /// default implementation should call `build_error!`, which prevents 170 /// calls to this function at compile time: 171 /// 172 /// ```compile_fail 173 /// # // Intentionally missing `use`s to simplify `rusttest`. 174 /// build_error!(VTABLE_DEFAULT_ERROR) 175 /// ``` 176 /// 177 /// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`]. 178 /// 179 /// This macro should not be used when all functions are required. 180 /// 181 /// Additionally, this macro automatically handles the `OwnerModule` 182 /// associated type: on the trait side, `type OwnerModule: ModuleMetadata;` 183 /// is added as a required associated type if not already defined; on the 184 /// impl side, `type OwnerModule = LocalModule;` is automatically inserted 185 /// if not explicitly defined. 186 /// 187 /// # Examples 188 /// 189 /// ``` 190 /// use kernel::error::VTABLE_DEFAULT_ERROR; 191 /// use kernel::prelude::*; 192 /// 193 /// # struct LocalModule; 194 /// # impl kernel::ModuleMetadata for LocalModule { 195 /// # const NAME: &'static kernel::str::CStr = c"vtable_doctest"; 196 /// # 197 /// # // SAFETY: This doctest runs on the host: there is no `THIS_MODULE`. 198 /// # const THIS_MODULE: kernel::ThisModule = unsafe { 199 /// # kernel::ThisModule::from_ptr(core::ptr::null_mut()) 200 /// # }; 201 /// # } 202 /// # 203 /// # fn main() { 204 /// // Declares a `#[vtable]` trait 205 /// #[vtable] 206 /// pub trait Operations: Send + Sync + Sized { 207 /// fn foo(&self) -> Result<()> { 208 /// build_error!(VTABLE_DEFAULT_ERROR) 209 /// } 210 /// 211 /// fn bar(&self) -> Result<()> { 212 /// build_error!(VTABLE_DEFAULT_ERROR) 213 /// } 214 /// } 215 /// 216 /// struct Foo; 217 /// 218 /// // Implements the `#[vtable]` trait 219 /// #[vtable] 220 /// impl Operations for Foo { 221 /// fn foo(&self) -> Result<()> { 222 /// # Err(EINVAL) 223 /// // ... 224 /// } 225 /// } 226 /// 227 /// assert_eq!(<Foo as Operations>::HAS_FOO, true); 228 /// assert_eq!(<Foo as Operations>::HAS_BAR, false); 229 /// # } 230 /// ``` 231 /// 232 /// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html 233 #[proc_macro_attribute] 234 pub fn vtable(attr: TokenStream, input: TokenStream) -> TokenStream { 235 parse_macro_input!(attr as syn::parse::Nothing); 236 vtable::vtable(parse_macro_input!(input)) 237 .unwrap_or_else(|e| e.into_compile_error()) 238 .into() 239 } 240 241 /// Export a function so that C code can call it via a header file. 242 /// 243 /// Functions exported using this macro can be called from C code using the declaration in the 244 /// appropriate header file. It should only be used in cases where C calls the function through a 245 /// header file; cases where C calls into Rust via a function pointer in a vtable (such as 246 /// `file_operations`) should not use this macro. 247 /// 248 /// This macro has the following effect: 249 /// 250 /// * Disables name mangling for this function. 251 /// * Verifies at compile-time that the function signature matches the declaration in the header 252 /// file. 253 /// 254 /// You must declare the signature of the Rust function in a header file that is included by 255 /// `rust/bindings/bindings_helper.h`. 256 /// 257 /// This macro is *not* the same as the C macros `EXPORT_SYMBOL_*`. All Rust symbols are currently 258 /// automatically exported with `EXPORT_SYMBOL_GPL`. 259 #[proc_macro_attribute] 260 pub fn export(attr: TokenStream, input: TokenStream) -> TokenStream { 261 parse_macro_input!(attr as syn::parse::Nothing); 262 export::export(parse_macro_input!(input)).into() 263 } 264 265 /// Like [`core::format_args!`], but automatically wraps arguments in [`kernel::fmt::Adapter`]. 266 /// 267 /// This macro allows generating `fmt::Arguments` while ensuring that each argument is wrapped with 268 /// `::kernel::fmt::Adapter`, which customizes formatting behavior for kernel logging. 269 /// 270 /// Named arguments used in the format string (e.g. `{foo}`) are detected and resolved from local 271 /// bindings. All positional and named arguments are automatically wrapped. 272 /// 273 /// This macro is an implementation detail of other kernel logging macros like [`pr_info!`] and 274 /// should not typically be used directly. 275 /// 276 /// [`kernel::fmt::Adapter`]: ../kernel/fmt/struct.Adapter.html 277 /// [`pr_info!`]: ../kernel/macro.pr_info.html 278 #[proc_macro] 279 pub fn fmt(input: TokenStream) -> TokenStream { 280 fmt::fmt(input.into()).into() 281 } 282 283 /// Concatenate two identifiers. 284 /// 285 /// This is useful in macros that need to declare or reference items with names 286 /// starting with a fixed prefix and ending in a user specified name. The resulting 287 /// identifier has the span of the second argument. 288 /// 289 /// # Examples 290 /// 291 /// ``` 292 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 293 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 294 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 295 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 296 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 297 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 298 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 299 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 300 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 301 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 302 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 303 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 304 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 305 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 306 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 307 /// use kernel::macros::concat_idents; 308 /// 309 /// macro_rules! pub_no_prefix { 310 /// ($prefix:ident, $($newname:ident),+) => { 311 /// $(pub(crate) const $newname: u32 = concat_idents!($prefix, $newname);)+ 312 /// }; 313 /// } 314 /// 315 /// pub_no_prefix!( 316 /// binder_driver_return_protocol_, 317 /// BR_OK, 318 /// BR_ERROR, 319 /// BR_TRANSACTION, 320 /// BR_REPLY, 321 /// BR_DEAD_REPLY, 322 /// BR_TRANSACTION_COMPLETE, 323 /// BR_INCREFS, 324 /// BR_ACQUIRE, 325 /// BR_RELEASE, 326 /// BR_DECREFS, 327 /// BR_NOOP, 328 /// BR_SPAWN_LOOPER, 329 /// BR_DEAD_BINDER, 330 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 331 /// BR_FAILED_REPLY 332 /// ); 333 /// 334 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 335 /// ``` 336 #[proc_macro] 337 pub fn concat_idents(input: TokenStream) -> TokenStream { 338 concat_idents::concat_idents(parse_macro_input!(input)).into() 339 } 340 341 /// Paste identifiers together. 342 /// 343 /// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a 344 /// single identifier. 345 /// 346 /// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and 347 /// literals (lifetimes and documentation strings are not supported). There is a difference in 348 /// supported modifiers as well. 349 /// 350 /// # Examples 351 /// 352 /// ``` 353 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 354 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 355 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 356 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 357 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 358 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 359 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 360 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 361 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 362 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 363 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 364 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 365 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 366 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 367 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 368 /// macro_rules! pub_no_prefix { 369 /// ($prefix:ident, $($newname:ident),+) => { 370 /// ::kernel::macros::paste! { 371 /// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+ 372 /// } 373 /// }; 374 /// } 375 /// 376 /// pub_no_prefix!( 377 /// binder_driver_return_protocol_, 378 /// BR_OK, 379 /// BR_ERROR, 380 /// BR_TRANSACTION, 381 /// BR_REPLY, 382 /// BR_DEAD_REPLY, 383 /// BR_TRANSACTION_COMPLETE, 384 /// BR_INCREFS, 385 /// BR_ACQUIRE, 386 /// BR_RELEASE, 387 /// BR_DECREFS, 388 /// BR_NOOP, 389 /// BR_SPAWN_LOOPER, 390 /// BR_DEAD_BINDER, 391 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 392 /// BR_FAILED_REPLY 393 /// ); 394 /// 395 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 396 /// ``` 397 /// 398 /// # Modifiers 399 /// 400 /// For each identifier, it is possible to attach one or multiple modifiers to 401 /// it. 402 /// 403 /// Currently supported modifiers are: 404 /// * `span`: change the span of concatenated identifier to the span of the specified token. By 405 /// default the span of the `[< >]` group is used. 406 /// * `lower`: change the identifier to lower case. 407 /// * `upper`: change the identifier to upper case. 408 /// 409 /// ``` 410 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 411 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 412 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 413 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 414 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 415 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 416 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 417 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 418 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 419 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 420 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 421 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 422 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 423 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 424 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 425 /// macro_rules! pub_no_prefix { 426 /// ($prefix:ident, $($newname:ident),+) => { 427 /// ::kernel::macros::paste! { 428 /// $(pub(crate) const fn [<$newname:lower:span>]() -> u32 { [<$prefix $newname:span>] })+ 429 /// } 430 /// }; 431 /// } 432 /// 433 /// pub_no_prefix!( 434 /// binder_driver_return_protocol_, 435 /// BR_OK, 436 /// BR_ERROR, 437 /// BR_TRANSACTION, 438 /// BR_REPLY, 439 /// BR_DEAD_REPLY, 440 /// BR_TRANSACTION_COMPLETE, 441 /// BR_INCREFS, 442 /// BR_ACQUIRE, 443 /// BR_RELEASE, 444 /// BR_DECREFS, 445 /// BR_NOOP, 446 /// BR_SPAWN_LOOPER, 447 /// BR_DEAD_BINDER, 448 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 449 /// BR_FAILED_REPLY 450 /// ); 451 /// 452 /// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK); 453 /// ``` 454 /// 455 /// # Literals 456 /// 457 /// Literals can also be concatenated with other identifiers: 458 /// 459 /// ``` 460 /// macro_rules! create_numbered_fn { 461 /// ($name:literal, $val:literal) => { 462 /// ::kernel::macros::paste! { 463 /// fn [<some_ $name _fn $val>]() -> u32 { $val } 464 /// } 465 /// }; 466 /// } 467 /// 468 /// create_numbered_fn!("foo", 100); 469 /// 470 /// assert_eq!(some_foo_fn100(), 100) 471 /// ``` 472 /// 473 /// [`paste`]: https://docs.rs/paste/ 474 #[proc_macro] 475 pub fn paste(input: TokenStream) -> TokenStream { 476 let mut tokens = proc_macro2::TokenStream::from(input).into_iter().collect(); 477 paste::expand(&mut tokens); 478 tokens 479 .into_iter() 480 .collect::<proc_macro2::TokenStream>() 481 .into() 482 } 483 484 /// Registers a KUnit test suite and its test cases using a user-space like syntax. 485 /// 486 /// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module 487 /// is ignored. 488 /// 489 /// # Examples 490 /// 491 /// ```ignore 492 /// # use kernel::prelude::*; 493 /// #[kunit_tests(kunit_test_suit_name)] 494 /// mod tests { 495 /// #[test] 496 /// fn foo() { 497 /// assert_eq!(1, 1); 498 /// } 499 /// 500 /// #[test] 501 /// fn bar() { 502 /// assert_eq!(2, 2); 503 /// } 504 /// } 505 /// ``` 506 #[proc_macro_attribute] 507 pub fn kunit_tests(attr: TokenStream, input: TokenStream) -> TokenStream { 508 kunit::kunit_tests(parse_macro_input!(attr), parse_macro_input!(input)) 509 .unwrap_or_else(|e| e.into_compile_error()) 510 .into() 511 } 512 513 /// Obtain a type that implements [`ForLt`] for the given higher-ranked type. 514 /// 515 /// Please refer to the documentation of the [`ForLt`] trait. 516 /// 517 /// [`ForLt`]: trait.ForLt.html 518 #[proc_macro] 519 #[allow(non_snake_case)] 520 pub fn ForLt(input: TokenStream) -> TokenStream { 521 for_lt::for_lt(parse_macro_input!(input)).into() 522 } 523 524 /// Obtain a type that implements [`CovariantForLt`] (and [`ForLt`]) for the given higher-ranked 525 /// type. 526 /// 527 /// Unlike [`ForLt!`], this macro additionally proves that the type is covariant over the lifetime, 528 /// providing a safe [`CovariantForLt::cast_ref`] method. 529 /// 530 /// Please refer to the documentation of the [`CovariantForLt`] trait. 531 /// 532 /// [`CovariantForLt`]: trait.CovariantForLt.html 533 /// [`CovariantForLt::cast_ref`]: trait.CovariantForLt.html#method.cast_ref 534 /// [`ForLt`]: trait.ForLt.html 535 #[proc_macro] 536 #[allow(non_snake_case)] 537 pub fn CovariantForLt(input: TokenStream) -> TokenStream { 538 for_lt::covariant_for_lt(parse_macro_input!(input)).into() 539 } 540