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 /// # Examples 181 /// 182 /// ``` 183 /// use kernel::error::VTABLE_DEFAULT_ERROR; 184 /// use kernel::prelude::*; 185 /// 186 /// // Declares a `#[vtable]` trait 187 /// #[vtable] 188 /// pub trait Operations: Send + Sync + Sized { 189 /// fn foo(&self) -> Result<()> { 190 /// build_error!(VTABLE_DEFAULT_ERROR) 191 /// } 192 /// 193 /// fn bar(&self) -> Result<()> { 194 /// build_error!(VTABLE_DEFAULT_ERROR) 195 /// } 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 /// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html 214 #[proc_macro_attribute] 215 pub fn vtable(attr: TokenStream, input: TokenStream) -> TokenStream { 216 parse_macro_input!(attr as syn::parse::Nothing); 217 vtable::vtable(parse_macro_input!(input)) 218 .unwrap_or_else(|e| e.into_compile_error()) 219 .into() 220 } 221 222 /// Export a function so that C code can call it via a header file. 223 /// 224 /// Functions exported using this macro can be called from C code using the declaration in the 225 /// appropriate header file. It should only be used in cases where C calls the function through a 226 /// header file; cases where C calls into Rust via a function pointer in a vtable (such as 227 /// `file_operations`) should not use this macro. 228 /// 229 /// This macro has the following effect: 230 /// 231 /// * Disables name mangling for this function. 232 /// * Verifies at compile-time that the function signature matches the declaration in the header 233 /// file. 234 /// 235 /// You must declare the signature of the Rust function in a header file that is included by 236 /// `rust/bindings/bindings_helper.h`. 237 /// 238 /// This macro is *not* the same as the C macros `EXPORT_SYMBOL_*`. All Rust symbols are currently 239 /// automatically exported with `EXPORT_SYMBOL_GPL`. 240 #[proc_macro_attribute] 241 pub fn export(attr: TokenStream, input: TokenStream) -> TokenStream { 242 parse_macro_input!(attr as syn::parse::Nothing); 243 export::export(parse_macro_input!(input)).into() 244 } 245 246 /// Like [`core::format_args!`], but automatically wraps arguments in [`kernel::fmt::Adapter`]. 247 /// 248 /// This macro allows generating `fmt::Arguments` while ensuring that each argument is wrapped with 249 /// `::kernel::fmt::Adapter`, which customizes formatting behavior for kernel logging. 250 /// 251 /// Named arguments used in the format string (e.g. `{foo}`) are detected and resolved from local 252 /// bindings. All positional and named arguments are automatically wrapped. 253 /// 254 /// This macro is an implementation detail of other kernel logging macros like [`pr_info!`] and 255 /// should not typically be used directly. 256 /// 257 /// [`kernel::fmt::Adapter`]: ../kernel/fmt/struct.Adapter.html 258 /// [`pr_info!`]: ../kernel/macro.pr_info.html 259 #[proc_macro] 260 pub fn fmt(input: TokenStream) -> TokenStream { 261 fmt::fmt(input.into()).into() 262 } 263 264 /// Concatenate two identifiers. 265 /// 266 /// This is useful in macros that need to declare or reference items with names 267 /// starting with a fixed prefix and ending in a user specified name. The resulting 268 /// identifier has the span of the second argument. 269 /// 270 /// # Examples 271 /// 272 /// ``` 273 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 274 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 275 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 276 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 277 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 278 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 279 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 280 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 281 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 282 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 283 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 284 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 285 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 286 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 287 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 288 /// use kernel::macros::concat_idents; 289 /// 290 /// macro_rules! pub_no_prefix { 291 /// ($prefix:ident, $($newname:ident),+) => { 292 /// $(pub(crate) const $newname: u32 = concat_idents!($prefix, $newname);)+ 293 /// }; 294 /// } 295 /// 296 /// pub_no_prefix!( 297 /// binder_driver_return_protocol_, 298 /// BR_OK, 299 /// BR_ERROR, 300 /// BR_TRANSACTION, 301 /// BR_REPLY, 302 /// BR_DEAD_REPLY, 303 /// BR_TRANSACTION_COMPLETE, 304 /// BR_INCREFS, 305 /// BR_ACQUIRE, 306 /// BR_RELEASE, 307 /// BR_DECREFS, 308 /// BR_NOOP, 309 /// BR_SPAWN_LOOPER, 310 /// BR_DEAD_BINDER, 311 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 312 /// BR_FAILED_REPLY 313 /// ); 314 /// 315 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 316 /// ``` 317 #[proc_macro] 318 pub fn concat_idents(input: TokenStream) -> TokenStream { 319 concat_idents::concat_idents(parse_macro_input!(input)).into() 320 } 321 322 /// Paste identifiers together. 323 /// 324 /// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a 325 /// single identifier. 326 /// 327 /// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and 328 /// literals (lifetimes and documentation strings are not supported). There is a difference in 329 /// supported modifiers as well. 330 /// 331 /// # Examples 332 /// 333 /// ``` 334 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 335 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 336 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 337 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 338 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 339 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 340 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 341 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 342 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 343 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 344 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 345 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 346 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 347 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 348 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 349 /// macro_rules! pub_no_prefix { 350 /// ($prefix:ident, $($newname:ident),+) => { 351 /// ::kernel::macros::paste! { 352 /// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+ 353 /// } 354 /// }; 355 /// } 356 /// 357 /// pub_no_prefix!( 358 /// binder_driver_return_protocol_, 359 /// BR_OK, 360 /// BR_ERROR, 361 /// BR_TRANSACTION, 362 /// BR_REPLY, 363 /// BR_DEAD_REPLY, 364 /// BR_TRANSACTION_COMPLETE, 365 /// BR_INCREFS, 366 /// BR_ACQUIRE, 367 /// BR_RELEASE, 368 /// BR_DECREFS, 369 /// BR_NOOP, 370 /// BR_SPAWN_LOOPER, 371 /// BR_DEAD_BINDER, 372 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 373 /// BR_FAILED_REPLY 374 /// ); 375 /// 376 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 377 /// ``` 378 /// 379 /// # Modifiers 380 /// 381 /// For each identifier, it is possible to attach one or multiple modifiers to 382 /// it. 383 /// 384 /// Currently supported modifiers are: 385 /// * `span`: change the span of concatenated identifier to the span of the specified token. By 386 /// default the span of the `[< >]` group is used. 387 /// * `lower`: change the identifier to lower case. 388 /// * `upper`: change the identifier to upper case. 389 /// 390 /// ``` 391 /// # const binder_driver_return_protocol_BR_OK: u32 = 0; 392 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1; 393 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2; 394 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3; 395 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4; 396 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5; 397 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6; 398 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7; 399 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8; 400 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9; 401 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10; 402 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11; 403 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12; 404 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13; 405 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14; 406 /// macro_rules! pub_no_prefix { 407 /// ($prefix:ident, $($newname:ident),+) => { 408 /// ::kernel::macros::paste! { 409 /// $(pub(crate) const fn [<$newname:lower:span>]() -> u32 { [<$prefix $newname:span>] })+ 410 /// } 411 /// }; 412 /// } 413 /// 414 /// pub_no_prefix!( 415 /// binder_driver_return_protocol_, 416 /// BR_OK, 417 /// BR_ERROR, 418 /// BR_TRANSACTION, 419 /// BR_REPLY, 420 /// BR_DEAD_REPLY, 421 /// BR_TRANSACTION_COMPLETE, 422 /// BR_INCREFS, 423 /// BR_ACQUIRE, 424 /// BR_RELEASE, 425 /// BR_DECREFS, 426 /// BR_NOOP, 427 /// BR_SPAWN_LOOPER, 428 /// BR_DEAD_BINDER, 429 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 430 /// BR_FAILED_REPLY 431 /// ); 432 /// 433 /// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK); 434 /// ``` 435 /// 436 /// # Literals 437 /// 438 /// Literals can also be concatenated with other identifiers: 439 /// 440 /// ``` 441 /// macro_rules! create_numbered_fn { 442 /// ($name:literal, $val:literal) => { 443 /// ::kernel::macros::paste! { 444 /// fn [<some_ $name _fn $val>]() -> u32 { $val } 445 /// } 446 /// }; 447 /// } 448 /// 449 /// create_numbered_fn!("foo", 100); 450 /// 451 /// assert_eq!(some_foo_fn100(), 100) 452 /// ``` 453 /// 454 /// [`paste`]: https://docs.rs/paste/ 455 #[proc_macro] 456 pub fn paste(input: TokenStream) -> TokenStream { 457 let mut tokens = proc_macro2::TokenStream::from(input).into_iter().collect(); 458 paste::expand(&mut tokens); 459 tokens 460 .into_iter() 461 .collect::<proc_macro2::TokenStream>() 462 .into() 463 } 464 465 /// Registers a KUnit test suite and its test cases using a user-space like syntax. 466 /// 467 /// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module 468 /// is ignored. 469 /// 470 /// # Examples 471 /// 472 /// ```ignore 473 /// # use kernel::prelude::*; 474 /// #[kunit_tests(kunit_test_suit_name)] 475 /// mod tests { 476 /// #[test] 477 /// fn foo() { 478 /// assert_eq!(1, 1); 479 /// } 480 /// 481 /// #[test] 482 /// fn bar() { 483 /// assert_eq!(2, 2); 484 /// } 485 /// } 486 /// ``` 487 #[proc_macro_attribute] 488 pub fn kunit_tests(attr: TokenStream, input: TokenStream) -> TokenStream { 489 kunit::kunit_tests(parse_macro_input!(attr), parse_macro_input!(input)) 490 .unwrap_or_else(|e| e.into_compile_error()) 491 .into() 492 } 493 494 /// Obtain a type that implements [`ForLt`] for the given higher-ranked type. 495 /// 496 /// Please refer to the documentation of the [`ForLt`] trait. 497 /// 498 /// [`ForLt`]: trait.ForLt.html 499 #[proc_macro] 500 // The macro shares the name with the trait. 501 #[allow(non_snake_case)] 502 pub fn ForLt(input: TokenStream) -> TokenStream { 503 for_lt::for_lt(parse_macro_input!(input)).into() 504 } 505