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 /// params: { 39 /// my_i32: i32 { 40 /// default: 42, 41 /// permissions: 0o000, 42 /// description: "Example of i32", 43 /// }, 44 /// writeable_i32: i32 { 45 /// default: 42, 46 /// permissions: 0o644, 47 /// description: "Example of i32", 48 /// }, 49 /// }, 50 /// } 51 /// 52 /// struct MyModule; 53 /// 54 /// impl kernel::Module for MyModule { 55 /// fn init() -> Result<Self> { 56 /// // If the parameter is writeable, then the kparam lock must be 57 /// // taken to read the parameter: 58 /// { 59 /// let lock = THIS_MODULE.kernel_param_lock(); 60 /// pr_info!("i32 param is: {}\n", writeable_i32.read(&lock)); 61 /// } 62 /// // If the parameter is read only, it can be read without locking 63 /// // the kernel parameters: 64 /// pr_info!("i32 param is: {}\n", my_i32.read()); 65 /// Ok(Self) 66 /// } 67 /// } 68 /// ``` 69 /// 70 /// # Supported argument types 71 /// - `type`: type which implements the [`Module`] trait (required). 72 /// - `name`: byte array of the name of the kernel module (required). 73 /// - `author`: byte array of the author of the kernel module. 74 /// - `description`: byte array of the description of the kernel module. 75 /// - `license`: byte array of the license of the kernel module (required). 76 /// - `alias`: byte array of alias name of the kernel module. 77 #[proc_macro] 78 pub fn module(ts: TokenStream) -> TokenStream { 79 module::module(ts) 80 } 81 82 /// Declares or implements a vtable trait. 83 /// 84 /// Linux's use of pure vtables is very close to Rust traits, but they differ 85 /// in how unimplemented functions are represented. In Rust, traits can provide 86 /// default implementation for all non-required methods (and the default 87 /// implementation could just return `Error::EINVAL`); Linux typically use C 88 /// `NULL` pointers to represent these functions. 89 /// 90 /// This attribute closes that gap. A trait can be annotated with the 91 /// `#[vtable]` attribute. Implementers of the trait will then also have to 92 /// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*` 93 /// associated constant bool for each method in the trait that is set to true if 94 /// the implementer has overridden the associated method. 95 /// 96 /// For a trait method to be optional, it must have a default implementation. 97 /// This is also the case for traits annotated with `#[vtable]`, but in this 98 /// case the default implementation will never be executed. The reason for this 99 /// is that the functions will be called through function pointers installed in 100 /// C side vtables. When an optional method is not implemented on a `#[vtable]` 101 /// trait, a NULL entry is installed in the vtable. Thus the default 102 /// implementation is never called. Since these traits are not designed to be 103 /// used on the Rust side, it should not be possible to call the default 104 /// implementation. This is done to ensure that we call the vtable methods 105 /// through the C vtable, and not through the Rust vtable. Therefore, the 106 /// default implementation should call `kernel::build_error`, which prevents 107 /// calls to this function at compile time: 108 /// 109 /// ```compile_fail 110 /// # use kernel::error::VTABLE_DEFAULT_ERROR; 111 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 112 /// ``` 113 /// 114 /// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`]. 115 /// 116 /// This macro should not be used when all functions are required. 117 /// 118 /// # Examples 119 /// 120 /// ```ignore 121 /// use kernel::error::VTABLE_DEFAULT_ERROR; 122 /// use kernel::prelude::*; 123 /// 124 /// // Declares a `#[vtable]` trait 125 /// #[vtable] 126 /// pub trait Operations: Send + Sync + Sized { 127 /// fn foo(&self) -> Result<()> { 128 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 129 /// } 130 /// 131 /// fn bar(&self) -> Result<()> { 132 /// kernel::build_error(VTABLE_DEFAULT_ERROR) 133 /// } 134 /// } 135 /// 136 /// struct Foo; 137 /// 138 /// // Implements the `#[vtable]` trait 139 /// #[vtable] 140 /// impl Operations for Foo { 141 /// fn foo(&self) -> Result<()> { 142 /// # Err(EINVAL) 143 /// // ... 144 /// } 145 /// } 146 /// 147 /// assert_eq!(<Foo as Operations>::HAS_FOO, true); 148 /// assert_eq!(<Foo as Operations>::HAS_BAR, false); 149 /// ``` 150 /// 151 /// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html 152 #[proc_macro_attribute] 153 pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream { 154 vtable::vtable(attr, ts) 155 } 156 157 /// Concatenate two identifiers. 158 /// 159 /// This is useful in macros that need to declare or reference items with names 160 /// starting with a fixed prefix and ending in a user specified name. The resulting 161 /// identifier has the span of the second argument. 162 /// 163 /// # Examples 164 /// 165 /// ```ignore 166 /// use kernel::macro::concat_idents; 167 /// 168 /// macro_rules! pub_no_prefix { 169 /// ($prefix:ident, $($newname:ident),+) => { 170 /// $(pub(crate) const $newname: u32 = kernel::macros::concat_idents!($prefix, $newname);)+ 171 /// }; 172 /// } 173 /// 174 /// pub_no_prefix!( 175 /// binder_driver_return_protocol_, 176 /// BR_OK, 177 /// BR_ERROR, 178 /// BR_TRANSACTION, 179 /// BR_REPLY, 180 /// BR_DEAD_REPLY, 181 /// BR_TRANSACTION_COMPLETE, 182 /// BR_INCREFS, 183 /// BR_ACQUIRE, 184 /// BR_RELEASE, 185 /// BR_DECREFS, 186 /// BR_NOOP, 187 /// BR_SPAWN_LOOPER, 188 /// BR_DEAD_BINDER, 189 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 190 /// BR_FAILED_REPLY 191 /// ); 192 /// 193 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 194 /// ``` 195 #[proc_macro] 196 pub fn concat_idents(ts: TokenStream) -> TokenStream { 197 concat_idents::concat_idents(ts) 198 } 199 200 /// Used to specify the pinning information of the fields of a struct. 201 /// 202 /// This is somewhat similar in purpose as 203 /// [pin-project-lite](https://crates.io/crates/pin-project-lite). 204 /// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each 205 /// field you want to structurally pin. 206 /// 207 /// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`, 208 /// then `#[pin]` directs the type of initializer that is required. 209 /// 210 /// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this 211 /// macro, and change your `Drop` implementation to `PinnedDrop` annotated with 212 /// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care. 213 /// 214 /// # Examples 215 /// 216 /// ```rust,ignore 217 /// #[pin_data] 218 /// struct DriverData { 219 /// #[pin] 220 /// queue: Mutex<Vec<Command>>, 221 /// buf: Box<[u8; 1024 * 1024]>, 222 /// } 223 /// ``` 224 /// 225 /// ```rust,ignore 226 /// #[pin_data(PinnedDrop)] 227 /// struct DriverData { 228 /// #[pin] 229 /// queue: Mutex<Vec<Command>>, 230 /// buf: Box<[u8; 1024 * 1024]>, 231 /// raw_info: *mut Info, 232 /// } 233 /// 234 /// #[pinned_drop] 235 /// impl PinnedDrop for DriverData { 236 /// fn drop(self: Pin<&mut Self>) { 237 /// unsafe { bindings::destroy_info(self.raw_info) }; 238 /// } 239 /// } 240 /// ``` 241 /// 242 /// [`pin_init!`]: ../kernel/macro.pin_init.html 243 // ^ cannot use direct link, since `kernel` is not a dependency of `macros`. 244 #[proc_macro_attribute] 245 pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream { 246 pin_data::pin_data(inner, item) 247 } 248 249 /// Used to implement `PinnedDrop` safely. 250 /// 251 /// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`. 252 /// 253 /// # Examples 254 /// 255 /// ```rust,ignore 256 /// #[pin_data(PinnedDrop)] 257 /// struct DriverData { 258 /// #[pin] 259 /// queue: Mutex<Vec<Command>>, 260 /// buf: Box<[u8; 1024 * 1024]>, 261 /// raw_info: *mut Info, 262 /// } 263 /// 264 /// #[pinned_drop] 265 /// impl PinnedDrop for DriverData { 266 /// fn drop(self: Pin<&mut Self>) { 267 /// unsafe { bindings::destroy_info(self.raw_info) }; 268 /// } 269 /// } 270 /// ``` 271 #[proc_macro_attribute] 272 pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream { 273 pinned_drop::pinned_drop(args, input) 274 } 275 276 /// Paste identifiers together. 277 /// 278 /// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a 279 /// single identifier. 280 /// 281 /// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and 282 /// literals (lifetimes and documentation strings are not supported). There is a difference in 283 /// supported modifiers as well. 284 /// 285 /// # Example 286 /// 287 /// ```ignore 288 /// use kernel::macro::paste; 289 /// 290 /// macro_rules! pub_no_prefix { 291 /// ($prefix:ident, $($newname:ident),+) => { 292 /// paste! { 293 /// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+ 294 /// } 295 /// }; 296 /// } 297 /// 298 /// pub_no_prefix!( 299 /// binder_driver_return_protocol_, 300 /// BR_OK, 301 /// BR_ERROR, 302 /// BR_TRANSACTION, 303 /// BR_REPLY, 304 /// BR_DEAD_REPLY, 305 /// BR_TRANSACTION_COMPLETE, 306 /// BR_INCREFS, 307 /// BR_ACQUIRE, 308 /// BR_RELEASE, 309 /// BR_DECREFS, 310 /// BR_NOOP, 311 /// BR_SPAWN_LOOPER, 312 /// BR_DEAD_BINDER, 313 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 314 /// BR_FAILED_REPLY 315 /// ); 316 /// 317 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK); 318 /// ``` 319 /// 320 /// # Modifiers 321 /// 322 /// For each identifier, it is possible to attach one or multiple modifiers to 323 /// it. 324 /// 325 /// Currently supported modifiers are: 326 /// * `span`: change the span of concatenated identifier to the span of the specified token. By 327 /// default the span of the `[< >]` group is used. 328 /// * `lower`: change the identifier to lower case. 329 /// * `upper`: change the identifier to upper case. 330 /// 331 /// ```ignore 332 /// use kernel::macro::paste; 333 /// 334 /// macro_rules! pub_no_prefix { 335 /// ($prefix:ident, $($newname:ident),+) => { 336 /// kernel::macros::paste! { 337 /// $(pub(crate) const fn [<$newname:lower:span>]: u32 = [<$prefix $newname:span>];)+ 338 /// } 339 /// }; 340 /// } 341 /// 342 /// pub_no_prefix!( 343 /// binder_driver_return_protocol_, 344 /// BR_OK, 345 /// BR_ERROR, 346 /// BR_TRANSACTION, 347 /// BR_REPLY, 348 /// BR_DEAD_REPLY, 349 /// BR_TRANSACTION_COMPLETE, 350 /// BR_INCREFS, 351 /// BR_ACQUIRE, 352 /// BR_RELEASE, 353 /// BR_DECREFS, 354 /// BR_NOOP, 355 /// BR_SPAWN_LOOPER, 356 /// BR_DEAD_BINDER, 357 /// BR_CLEAR_DEATH_NOTIFICATION_DONE, 358 /// BR_FAILED_REPLY 359 /// ); 360 /// 361 /// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK); 362 /// ``` 363 /// 364 /// # Literals 365 /// 366 /// Literals can also be concatenated with other identifiers: 367 /// 368 /// ```ignore 369 /// macro_rules! create_numbered_fn { 370 /// ($name:literal, $val:literal) => { 371 /// kernel::macros::paste! { 372 /// fn [<some_ $name _fn $val>]() -> u32 { $val } 373 /// } 374 /// }; 375 /// } 376 /// 377 /// create_numbered_fn!("foo", 100); 378 /// 379 /// assert_eq!(some_foo_fn100(), 100) 380 /// ``` 381 /// 382 /// [`paste`]: https://docs.rs/paste/ 383 #[proc_macro] 384 pub fn paste(input: TokenStream) -> TokenStream { 385 let mut tokens = input.into_iter().collect(); 386 paste::expand(&mut tokens); 387 tokens.into_iter().collect() 388 } 389 390 /// Derives the [`Zeroable`] trait for the given struct. 391 /// 392 /// This can only be used for structs where every field implements the [`Zeroable`] trait. 393 /// 394 /// # Examples 395 /// 396 /// ```rust,ignore 397 /// #[derive(Zeroable)] 398 /// pub struct DriverData { 399 /// id: i64, 400 /// buf_ptr: *mut u8, 401 /// len: usize, 402 /// } 403 /// ``` 404 #[proc_macro_derive(Zeroable)] 405 pub fn derive_zeroable(input: TokenStream) -> TokenStream { 406 zeroable::derive(input) 407 } 408