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