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 /// 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 /// ```
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]
module(ts: TokenStream) -> TokenStream134 pub fn module(ts: TokenStream) -> TokenStream {
135 module::module(ts)
136 }
137
138 /// Declares or implements a vtable trait.
139 ///
140 /// Linux's use of pure vtables is very close to Rust traits, but they differ
141 /// in how unimplemented functions are represented. In Rust, traits can provide
142 /// default implementation for all non-required methods (and the default
143 /// implementation could just return `Error::EINVAL`); Linux typically use C
144 /// `NULL` pointers to represent these functions.
145 ///
146 /// This attribute closes that gap. A trait can be annotated with the
147 /// `#[vtable]` attribute. Implementers of the trait will then also have to
148 /// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*`
149 /// associated constant bool for each method in the trait that is set to true if
150 /// the implementer has overridden the associated method.
151 ///
152 /// For a trait method to be optional, it must have a default implementation.
153 /// This is also the case for traits annotated with `#[vtable]`, but in this
154 /// case the default implementation will never be executed. The reason for this
155 /// is that the functions will be called through function pointers installed in
156 /// C side vtables. When an optional method is not implemented on a `#[vtable]`
157 /// trait, a NULL entry is installed in the vtable. Thus the default
158 /// implementation is never called. Since these traits are not designed to be
159 /// used on the Rust side, it should not be possible to call the default
160 /// implementation. This is done to ensure that we call the vtable methods
161 /// through the C vtable, and not through the Rust vtable. Therefore, the
162 /// default implementation should call `build_error!`, which prevents
163 /// calls to this function at compile time:
164 ///
165 /// ```compile_fail
166 /// # // Intentionally missing `use`s to simplify `rusttest`.
167 /// build_error!(VTABLE_DEFAULT_ERROR)
168 /// ```
169 ///
170 /// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`].
171 ///
172 /// This macro should not be used when all functions are required.
173 ///
174 /// # Examples
175 ///
176 /// ```
177 /// use kernel::error::VTABLE_DEFAULT_ERROR;
178 /// use kernel::prelude::*;
179 ///
180 /// // Declares a `#[vtable]` trait
181 /// #[vtable]
182 /// pub trait Operations: Send + Sync + Sized {
183 /// fn foo(&self) -> Result<()> {
184 /// build_error!(VTABLE_DEFAULT_ERROR)
185 /// }
186 ///
187 /// fn bar(&self) -> Result<()> {
188 /// build_error!(VTABLE_DEFAULT_ERROR)
189 /// }
190 /// }
191 ///
192 /// struct Foo;
193 ///
194 /// // Implements the `#[vtable]` trait
195 /// #[vtable]
196 /// impl Operations for Foo {
197 /// fn foo(&self) -> Result<()> {
198 /// # Err(EINVAL)
199 /// // ...
200 /// }
201 /// }
202 ///
203 /// assert_eq!(<Foo as Operations>::HAS_FOO, true);
204 /// assert_eq!(<Foo as Operations>::HAS_BAR, false);
205 /// ```
206 ///
207 /// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html
208 #[proc_macro_attribute]
vtable(attr: TokenStream, ts: TokenStream) -> TokenStream209 pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
210 vtable::vtable(attr, ts)
211 }
212
213 /// Export a function so that C code can call it via a header file.
214 ///
215 /// Functions exported using this macro can be called from C code using the declaration in the
216 /// appropriate header file. It should only be used in cases where C calls the function through a
217 /// header file; cases where C calls into Rust via a function pointer in a vtable (such as
218 /// `file_operations`) should not use this macro.
219 ///
220 /// This macro has the following effect:
221 ///
222 /// * Disables name mangling for this function.
223 /// * Verifies at compile-time that the function signature matches the declaration in the header
224 /// file.
225 ///
226 /// You must declare the signature of the Rust function in a header file that is included by
227 /// `rust/bindings/bindings_helper.h`.
228 ///
229 /// This macro is *not* the same as the C macros `EXPORT_SYMBOL_*`. All Rust symbols are currently
230 /// automatically exported with `EXPORT_SYMBOL_GPL`.
231 #[proc_macro_attribute]
export(attr: TokenStream, ts: TokenStream) -> TokenStream232 pub fn export(attr: TokenStream, ts: TokenStream) -> TokenStream {
233 export::export(attr, ts)
234 }
235
236 /// Like [`core::format_args!`], but automatically wraps arguments in [`kernel::fmt::Adapter`].
237 ///
238 /// This macro allows generating `fmt::Arguments` while ensuring that each argument is wrapped with
239 /// `::kernel::fmt::Adapter`, which customizes formatting behavior for kernel logging.
240 ///
241 /// Named arguments used in the format string (e.g. `{foo}`) are detected and resolved from local
242 /// bindings. All positional and named arguments are automatically wrapped.
243 ///
244 /// This macro is an implementation detail of other kernel logging macros like [`pr_info!`] and
245 /// should not typically be used directly.
246 ///
247 /// [`kernel::fmt::Adapter`]: ../kernel/fmt/struct.Adapter.html
248 /// [`pr_info!`]: ../kernel/macro.pr_info.html
249 #[proc_macro]
fmt(input: TokenStream) -> TokenStream250 pub fn fmt(input: TokenStream) -> TokenStream {
251 fmt::fmt(input)
252 }
253
254 /// Concatenate two identifiers.
255 ///
256 /// This is useful in macros that need to declare or reference items with names
257 /// starting with a fixed prefix and ending in a user specified name. The resulting
258 /// identifier has the span of the second argument.
259 ///
260 /// # Examples
261 ///
262 /// ```
263 /// # const binder_driver_return_protocol_BR_OK: u32 = 0;
264 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
265 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
266 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
267 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
268 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
269 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
270 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
271 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
272 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
273 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
274 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
275 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
276 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
277 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
278 /// use kernel::macros::concat_idents;
279 ///
280 /// macro_rules! pub_no_prefix {
281 /// ($prefix:ident, $($newname:ident),+) => {
282 /// $(pub(crate) const $newname: u32 = concat_idents!($prefix, $newname);)+
283 /// };
284 /// }
285 ///
286 /// pub_no_prefix!(
287 /// binder_driver_return_protocol_,
288 /// BR_OK,
289 /// BR_ERROR,
290 /// BR_TRANSACTION,
291 /// BR_REPLY,
292 /// BR_DEAD_REPLY,
293 /// BR_TRANSACTION_COMPLETE,
294 /// BR_INCREFS,
295 /// BR_ACQUIRE,
296 /// BR_RELEASE,
297 /// BR_DECREFS,
298 /// BR_NOOP,
299 /// BR_SPAWN_LOOPER,
300 /// BR_DEAD_BINDER,
301 /// BR_CLEAR_DEATH_NOTIFICATION_DONE,
302 /// BR_FAILED_REPLY
303 /// );
304 ///
305 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
306 /// ```
307 #[proc_macro]
concat_idents(ts: TokenStream) -> TokenStream308 pub fn concat_idents(ts: TokenStream) -> TokenStream {
309 concat_idents::concat_idents(ts)
310 }
311
312 /// Paste identifiers together.
313 ///
314 /// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a
315 /// single identifier.
316 ///
317 /// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and
318 /// literals (lifetimes and documentation strings are not supported). There is a difference in
319 /// supported modifiers as well.
320 ///
321 /// # Examples
322 ///
323 /// ```
324 /// # const binder_driver_return_protocol_BR_OK: u32 = 0;
325 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
326 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
327 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
328 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
329 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
330 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
331 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
332 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
333 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
334 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
335 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
336 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
337 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
338 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
339 /// macro_rules! pub_no_prefix {
340 /// ($prefix:ident, $($newname:ident),+) => {
341 /// ::kernel::macros::paste! {
342 /// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+
343 /// }
344 /// };
345 /// }
346 ///
347 /// pub_no_prefix!(
348 /// binder_driver_return_protocol_,
349 /// BR_OK,
350 /// BR_ERROR,
351 /// BR_TRANSACTION,
352 /// BR_REPLY,
353 /// BR_DEAD_REPLY,
354 /// BR_TRANSACTION_COMPLETE,
355 /// BR_INCREFS,
356 /// BR_ACQUIRE,
357 /// BR_RELEASE,
358 /// BR_DECREFS,
359 /// BR_NOOP,
360 /// BR_SPAWN_LOOPER,
361 /// BR_DEAD_BINDER,
362 /// BR_CLEAR_DEATH_NOTIFICATION_DONE,
363 /// BR_FAILED_REPLY
364 /// );
365 ///
366 /// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
367 /// ```
368 ///
369 /// # Modifiers
370 ///
371 /// For each identifier, it is possible to attach one or multiple modifiers to
372 /// it.
373 ///
374 /// Currently supported modifiers are:
375 /// * `span`: change the span of concatenated identifier to the span of the specified token. By
376 /// default the span of the `[< >]` group is used.
377 /// * `lower`: change the identifier to lower case.
378 /// * `upper`: change the identifier to upper case.
379 ///
380 /// ```
381 /// # const binder_driver_return_protocol_BR_OK: u32 = 0;
382 /// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
383 /// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
384 /// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
385 /// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
386 /// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
387 /// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
388 /// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
389 /// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
390 /// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
391 /// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
392 /// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
393 /// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
394 /// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
395 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
396 /// macro_rules! pub_no_prefix {
397 /// ($prefix:ident, $($newname:ident),+) => {
398 /// ::kernel::macros::paste! {
399 /// $(pub(crate) const fn [<$newname:lower:span>]() -> u32 { [<$prefix $newname:span>] })+
400 /// }
401 /// };
402 /// }
403 ///
404 /// pub_no_prefix!(
405 /// binder_driver_return_protocol_,
406 /// BR_OK,
407 /// BR_ERROR,
408 /// BR_TRANSACTION,
409 /// BR_REPLY,
410 /// BR_DEAD_REPLY,
411 /// BR_TRANSACTION_COMPLETE,
412 /// BR_INCREFS,
413 /// BR_ACQUIRE,
414 /// BR_RELEASE,
415 /// BR_DECREFS,
416 /// BR_NOOP,
417 /// BR_SPAWN_LOOPER,
418 /// BR_DEAD_BINDER,
419 /// BR_CLEAR_DEATH_NOTIFICATION_DONE,
420 /// BR_FAILED_REPLY
421 /// );
422 ///
423 /// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK);
424 /// ```
425 ///
426 /// # Literals
427 ///
428 /// Literals can also be concatenated with other identifiers:
429 ///
430 /// ```
431 /// macro_rules! create_numbered_fn {
432 /// ($name:literal, $val:literal) => {
433 /// ::kernel::macros::paste! {
434 /// fn [<some_ $name _fn $val>]() -> u32 { $val }
435 /// }
436 /// };
437 /// }
438 ///
439 /// create_numbered_fn!("foo", 100);
440 ///
441 /// assert_eq!(some_foo_fn100(), 100)
442 /// ```
443 ///
444 /// [`paste`]: https://docs.rs/paste/
445 #[proc_macro]
paste(input: TokenStream) -> TokenStream446 pub fn paste(input: TokenStream) -> TokenStream {
447 let mut tokens = input.into_iter().collect();
448 paste::expand(&mut tokens);
449 tokens.into_iter().collect()
450 }
451
452 /// Registers a KUnit test suite and its test cases using a user-space like syntax.
453 ///
454 /// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module
455 /// is ignored.
456 ///
457 /// # Examples
458 ///
459 /// ```ignore
460 /// # use kernel::prelude::*;
461 /// #[kunit_tests(kunit_test_suit_name)]
462 /// mod tests {
463 /// #[test]
464 /// fn foo() {
465 /// assert_eq!(1, 1);
466 /// }
467 ///
468 /// #[test]
469 /// fn bar() {
470 /// assert_eq!(2, 2);
471 /// }
472 /// }
473 /// ```
474 #[proc_macro_attribute]
kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream475 pub fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
476 kunit::kunit_tests(attr, ts)
477 }
478