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