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