1 // SPDX-License-Identifier: GPL-2.0 2 3 //! Crate for all kernel procedural macros. 4 5 #[macro_use] 6 mod quote; 7 mod concat_idents; 8 mod helpers; 9 mod module; 10 mod paste; 11 mod pin_data; 12 mod pinned_drop; 13 mod vtable; 14 mod zeroable; 15 16 use proc_macro::TokenStream; 17 18 /// Declares a kernel module. 19 /// 20 /// The `type` argument should be a type which implements the [`Module`] 21 /// trait. Also accepts various forms of kernel metadata. 22 /// 23 /// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h) 24 /// 25 /// [`Module`]: ../kernel/trait.Module.html 26 /// 27 /// # Examples 28 /// 29 /// ```ignore 30 /// use kernel::prelude::*; 31 /// 32 /// module!{ 33 /// type: MyModule, 34 /// name: "my_kernel_module", 35 /// author: "Rust for Linux Contributors", 36 /// description: "My very own kernel module!", 37 /// license: "GPL", 38 /// alias: ["alternate_module_name"], 39 /// } 40 /// 41 /// struct MyModule; 42 /// 43 /// impl kernel::Module for MyModule { 44 /// fn init() -> Result<Self> { 45 /// // If the parameter is writeable, then the kparam lock must be 46 /// // taken to read the parameter: 47 /// { 48 /// let lock = THIS_MODULE.kernel_param_lock(); 49 /// pr_info!("i32 param is: {}\n", writeable_i32.read(&lock)); 50 /// } 51 /// // If the parameter is read only, it can be read without locking 52 /// // the kernel parameters: 53 /// pr_info!("i32 param is: {}\n", my_i32.read()); 54 /// Ok(Self) 55 /// } 56 /// } 57 /// ``` 58 /// 59 /// ## Firmware 60 /// 61 /// The following example shows how to declare a kernel module that needs 62 /// to load binary firmware files. You need to specify the file names of 63 /// the firmware in the `firmware` field. The information is embedded 64 /// in the `modinfo` section of the kernel module. For example, a tool to 65 /// build an initramfs uses this information to put the firmware files into 66 /// the initramfs image. 67 /// 68 /// ```ignore 69 /// use kernel::prelude::*; 70 /// 71 /// module!{ 72 /// type: MyDeviceDriverModule, 73 /// name: "my_device_driver_module", 74 /// author: "Rust for Linux Contributors", 75 /// description: "My device driver requires firmware", 76 /// license: "GPL", 77 /// firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"], 78 /// } 79 /// 80 /// struct MyDeviceDriverModule; 81 /// 82 /// impl kernel::Module for MyDeviceDriverModule { 83 /// fn init() -> Result<Self> { 84 /// Ok(Self) 85 /// } 86 /// } 87 /// ``` 88 /// 89 /// # Supported argument types 90 /// - `type`: type which implements the [`Module`] trait (required). 91 /// - `name`: ASCII string literal of the name of the kernel module (required). 92 /// - `author`: string literal of the author of the kernel module. 93 /// - `description`: string literal of the description of the kernel module. 94 /// - `license`: ASCII string literal of the license of the kernel module (required). 95 /// - `alias`: array of ASCII string literals of the alias names of the kernel module. 96 /// - `firmware`: array of ASCII string literals of the firmware files of 97 /// the kernel module. 98 #[proc_macro] 99 pub fn module(ts: TokenStream) -> TokenStream { 100 module::module(ts) 101 } 102 103 /// Declares or implements a vtable trait. 104 /// 105 /// Linux's use of pure vtables is very close to Rust traits, but they differ 106 /// in how unimplemented functions are represented. In Rust, traits can provide 107 /// default implementation for all non-required methods (and the default 108 /// implementation could just return `Error::EINVAL`); Linux typically use C 109 /// `NULL` pointers to represent these functions. 110 /// 111 /// This attribute closes that gap. A trait can be annotated with the 112 /// `#[vtable]` attribute. Implementers of the trait will then also have to 113 /// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*` 114 /// associated constant bool for each method in the trait that is set to true if 115 /// the implementer has overridden the associated method. 116 /// 117 /// For a trait method to be optional, it must have a default implementation. 118 /// This is also the case for traits annotated with `#[vtable]`, but in this 119 /// case the default implementation will never be executed. The reason for this 120 /// is that the functions will be called through function pointers installed in 121 /// C side vtables. When an optional method is not implemented on a `#[vtable]` 122 /// trait, a NULL entry is installed in the vtable. Thus the default 123 /// implementation is never called. Since these traits are not designed to be 124 /// used on the Rust side, it should not be possible to call the default 125 /// implementation. This is done to ensure that we call the vtable methods 126 /// through the C vtable, and not through the Rust vtable. Therefore, the 127 /// default implementation should call `kernel::build_error`, which prevents 128 /// calls to this function at compile time: 129 /// 130 /// ```compile_fail 131 /// # use kernel::error::VTABLE_DEFAULT_ERROR; 132 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 133 /// ``` 134 /// 135 /// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`]. 136 /// 137 /// This macro should not be used when all functions are required. 138 /// 139 /// # Examples 140 /// 141 /// ```ignore 142 /// use kernel::error::VTABLE_DEFAULT_ERROR; 143 /// use kernel::prelude::*; 144 /// 145 /// // Declares a `#[vtable]` trait 146 /// #[vtable] 147 /// pub trait Operations: Send + Sync + Sized { 148 /// fn foo(&self) -> Result<()> { 149 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 150 /// } 151 /// 152 /// fn bar(&self) -> Result<()> { 153 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 154 /// } 155 /// } 156 /// 157 /// struct Foo; 158 /// 159 /// // Implements the `#[vtable]` trait 160 /// #[vtable] 161 /// impl Operations for Foo { 162 /// fn foo(&self) -> Result<()> { 163 /// # Err(EINVAL) 164 /// // ... 165 /// } 166 /// } 167 /// 168 /// assert_eq!(<Foo as Operations>::HAS_FOO, true); 169 /// assert_eq!(<Foo as Operations>::HAS_BAR, false); 170 /// ``` 171 /// 172 /// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html 173 #[proc_macro_attribute] 174 pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream { 175 vtable::vtable(attr, ts) 176 } 177 178 /// Concatenate two identifiers. 179 /// 180 /// This is useful in macros that need to declare or reference items with names 181 /// starting with a fixed prefix and ending in a user specified name. The resulting 182 /// identifier has the span of the second argument. 183 /// 184 /// # Examples 185 /// 186 /// ```ignore 187 /// use kernel::macro::concat_idents; 188 /// 189 /// macro_rules! pub_no_prefix { 190 /// ($prefix:ident, $($newname:ident),+) => { 191 /// $(pub(crate) const $newname: u32 = kernel::macros::concat_idents!($prefix, $newname);)+ 192 /// }; 193 /// } 194 /// 195 /// pub_no_prefix!( 196 /// binder_driver_return_protocol_, 197 /// BR_OK, 198 /// BR_ERROR, 199 /// BR_TRANSACTION, 200 /// BR_REPLY, 201 /// BR_DEAD_REPLY, 202 /// BR_TRANSACTION_COMPLETE, 203 /// BR_INCREFS, 204 /// BR_ACQUIRE, 205 /// BR_RELEASE, 206 /// BR_DECREFS, 207 /// BR_NOOP, 208 /// BR_SPAWN_LOOPER, 209 /// BR_DEAD_BINDER, 210 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 211 /// BR_FAILED_REPLY 212 /// ); 213 /// 214 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 215 /// ``` 216 #[proc_macro] 217 pub fn concat_idents(ts: TokenStream) -> TokenStream { 218 concat_idents::concat_idents(ts) 219 } 220 221 /// Used to specify the pinning information of the fields of a struct. 222 /// 223 /// This is somewhat similar in purpose as 224 /// [pin-project-lite](https://crates.io/crates/pin-project-lite). 225 /// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each 226 /// field you want to structurally pin. 227 /// 228 /// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`, 229 /// then `#[pin]` directs the type of initializer that is required. 230 /// 231 /// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this 232 /// macro, and change your `Drop` implementation to `PinnedDrop` annotated with 233 /// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care. 234 /// 235 /// # Examples 236 /// 237 /// ```rust,ignore 238 /// #[pin_data] 239 /// struct DriverData { 240 /// #[pin] 241 /// queue: Mutex<Vec<Command>>, 242 /// buf: Box<[u8; 1024 * 1024]>, 243 /// } 244 /// ``` 245 /// 246 /// ```rust,ignore 247 /// #[pin_data(PinnedDrop)] 248 /// struct DriverData { 249 /// #[pin] 250 /// queue: Mutex<Vec<Command>>, 251 /// buf: Box<[u8; 1024 * 1024]>, 252 /// raw_info: *mut Info, 253 /// } 254 /// 255 /// #[pinned_drop] 256 /// impl PinnedDrop for DriverData { 257 /// fn drop(self: Pin<&mut Self>) { 258 /// unsafe { bindings::destroy_info(self.raw_info) }; 259 /// } 260 /// } 261 /// ``` 262 /// 263 /// [`pin_init!`]: ../kernel/macro.pin_init.html 264 // ^ cannot use direct link, since `kernel` is not a dependency of `macros`. 265 #[proc_macro_attribute] 266 pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream { 267 pin_data::pin_data(inner, item) 268 } 269 270 /// Used to implement `PinnedDrop` safely. 271 /// 272 /// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`. 273 /// 274 /// # Examples 275 /// 276 /// ```rust,ignore 277 /// #[pin_data(PinnedDrop)] 278 /// struct DriverData { 279 /// #[pin] 280 /// queue: Mutex<Vec<Command>>, 281 /// buf: Box<[u8; 1024 * 1024]>, 282 /// raw_info: *mut Info, 283 /// } 284 /// 285 /// #[pinned_drop] 286 /// impl PinnedDrop for DriverData { 287 /// fn drop(self: Pin<&mut Self>) { 288 /// unsafe { bindings::destroy_info(self.raw_info) }; 289 /// } 290 /// } 291 /// ``` 292 #[proc_macro_attribute] 293 pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream { 294 pinned_drop::pinned_drop(args, input) 295 } 296 297 /// Paste identifiers together. 298 /// 299 /// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a 300 /// single identifier. 301 /// 302 /// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and 303 /// literals (lifetimes and documentation strings are not supported). There is a difference in 304 /// supported modifiers as well. 305 /// 306 /// # Example 307 /// 308 /// ```ignore 309 /// use kernel::macro::paste; 310 /// 311 /// macro_rules! pub_no_prefix { 312 /// ($prefix:ident, $($newname:ident),+) => { 313 /// paste! { 314 /// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+ 315 /// } 316 /// }; 317 /// } 318 /// 319 /// pub_no_prefix!( 320 /// binder_driver_return_protocol_, 321 /// BR_OK, 322 /// BR_ERROR, 323 /// BR_TRANSACTION, 324 /// BR_REPLY, 325 /// BR_DEAD_REPLY, 326 /// BR_TRANSACTION_COMPLETE, 327 /// BR_INCREFS, 328 /// BR_ACQUIRE, 329 /// BR_RELEASE, 330 /// BR_DECREFS, 331 /// BR_NOOP, 332 /// BR_SPAWN_LOOPER, 333 /// BR_DEAD_BINDER, 334 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 335 /// BR_FAILED_REPLY 336 /// ); 337 /// 338 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 339 /// ``` 340 /// 341 /// # Modifiers 342 /// 343 /// For each identifier, it is possible to attach one or multiple modifiers to 344 /// it. 345 /// 346 /// Currently supported modifiers are: 347 /// * `span`: change the span of concatenated identifier to the span of the specified token. By 348 /// default the span of the `[< >]` group is used. 349 /// * `lower`: change the identifier to lower case. 350 /// * `upper`: change the identifier to upper case. 351 /// 352 /// ```ignore 353 /// use kernel::macro::paste; 354 /// 355 /// macro_rules! pub_no_prefix { 356 /// ($prefix:ident, $($newname:ident),+) => { 357 /// kernel::macros::paste! { 358 /// $(pub(crate) const fn [<$newname:lower:span>]: u32 = [<$prefix $newname:span>];)+ 359 /// } 360 /// }; 361 /// } 362 /// 363 /// pub_no_prefix!( 364 /// binder_driver_return_protocol_, 365 /// BR_OK, 366 /// BR_ERROR, 367 /// BR_TRANSACTION, 368 /// BR_REPLY, 369 /// BR_DEAD_REPLY, 370 /// BR_TRANSACTION_COMPLETE, 371 /// BR_INCREFS, 372 /// BR_ACQUIRE, 373 /// BR_RELEASE, 374 /// BR_DECREFS, 375 /// BR_NOOP, 376 /// BR_SPAWN_LOOPER, 377 /// BR_DEAD_BINDER, 378 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 379 /// BR_FAILED_REPLY 380 /// ); 381 /// 382 /// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK); 383 /// ``` 384 /// 385 /// # Literals 386 /// 387 /// Literals can also be concatenated with other identifiers: 388 /// 389 /// ```ignore 390 /// macro_rules! create_numbered_fn { 391 /// ($name:literal, $val:literal) => { 392 /// kernel::macros::paste! { 393 /// fn [<some_ $name _fn $val>]() -> u32 { $val } 394 /// } 395 /// }; 396 /// } 397 /// 398 /// create_numbered_fn!("foo", 100); 399 /// 400 /// assert_eq!(some_foo_fn100(), 100) 401 /// ``` 402 /// 403 /// [`paste`]: https://docs.rs/paste/ 404 #[proc_macro] 405 pub fn paste(input: TokenStream) -> TokenStream { 406 let mut tokens = input.into_iter().collect(); 407 paste::expand(&mut tokens); 408 tokens.into_iter().collect() 409 } 410 411 /// Derives the [`Zeroable`] trait for the given struct. 412 /// 413 /// This can only be used for structs where every field implements the [`Zeroable`] trait. 414 /// 415 /// # Examples 416 /// 417 /// ```rust,ignore 418 /// #[derive(Zeroable)] 419 /// pub struct DriverData { 420 /// id: i64, 421 /// buf_ptr: *mut u8, 422 /// len: usize, 423 /// } 424 /// ``` 425 #[proc_macro_derive(Zeroable)] 426 pub fn derive_zeroable(input: TokenStream) -> TokenStream { 427 zeroable::derive(input) 428 } 429