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