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