macros/
lib.rs

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#[macro_use]
10mod quote;
11mod concat_idents;
12mod export;
13mod helpers;
14mod kunit;
15mod module;
16mod paste;
17mod vtable;
18
19use proc_macro::TokenStream;
20
21/// Declares a kernel module.
22///
23/// The `type` argument should be a type which implements the [`Module`]
24/// trait. Also accepts various forms of kernel metadata.
25///
26/// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h)
27///
28/// [`Module`]: ../kernel/trait.Module.html
29///
30/// # Examples
31///
32/// ```
33/// use kernel::prelude::*;
34///
35/// module!{
36///     type: MyModule,
37///     name: "my_kernel_module",
38///     authors: ["Rust for Linux Contributors"],
39///     description: "My very own kernel module!",
40///     license: "GPL",
41///     alias: ["alternate_module_name"],
42/// }
43///
44/// struct MyModule(i32);
45///
46/// impl kernel::Module for MyModule {
47///     fn init(_module: &'static ThisModule) -> Result<Self> {
48///         let foo: i32 = 42;
49///         pr_info!("I contain:  {}\n", foo);
50///         Ok(Self(foo))
51///     }
52/// }
53/// # fn main() {}
54/// ```
55///
56/// ## Firmware
57///
58/// The following example shows how to declare a kernel module that needs
59/// to load binary firmware files. You need to specify the file names of
60/// the firmware in the `firmware` field. The information is embedded
61/// in the `modinfo` section of the kernel module. For example, a tool to
62/// build an initramfs uses this information to put the firmware files into
63/// the initramfs image.
64///
65/// ```
66/// use kernel::prelude::*;
67///
68/// module!{
69///     type: MyDeviceDriverModule,
70///     name: "my_device_driver_module",
71///     authors: ["Rust for Linux Contributors"],
72///     description: "My device driver requires firmware",
73///     license: "GPL",
74///     firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"],
75/// }
76///
77/// struct MyDeviceDriverModule;
78///
79/// impl kernel::Module for MyDeviceDriverModule {
80///     fn init(_module: &'static ThisModule) -> Result<Self> {
81///         Ok(Self)
82///     }
83/// }
84/// # fn main() {}
85/// ```
86///
87/// # Supported argument types
88///   - `type`: type which implements the [`Module`] trait (required).
89///   - `name`: ASCII string literal of the name of the kernel module (required).
90///   - `authors`: array of ASCII string literals of the authors of the kernel module.
91///   - `description`: string literal of the description of the kernel module.
92///   - `license`: ASCII string literal of the license of the kernel module (required).
93///   - `alias`: array of ASCII string literals of the alias names of the kernel module.
94///   - `firmware`: array of ASCII string literals of the firmware files of
95///     the kernel module.
96#[proc_macro]
97pub fn module(ts: TokenStream) -> TokenStream {
98    module::module(ts)
99}
100
101/// Declares or implements a vtable trait.
102///
103/// Linux's use of pure vtables is very close to Rust traits, but they differ
104/// in how unimplemented functions are represented. In Rust, traits can provide
105/// default implementation for all non-required methods (and the default
106/// implementation could just return `Error::EINVAL`); Linux typically use C
107/// `NULL` pointers to represent these functions.
108///
109/// This attribute closes that gap. A trait can be annotated with the
110/// `#[vtable]` attribute. Implementers of the trait will then also have to
111/// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*`
112/// associated constant bool for each method in the trait that is set to true if
113/// the implementer has overridden the associated method.
114///
115/// For a trait method to be optional, it must have a default implementation.
116/// This is also the case for traits annotated with `#[vtable]`, but in this
117/// case the default implementation will never be executed. The reason for this
118/// is that the functions will be called through function pointers installed in
119/// C side vtables. When an optional method is not implemented on a `#[vtable]`
120/// trait, a NULL entry is installed in the vtable. Thus the default
121/// implementation is never called. Since these traits are not designed to be
122/// used on the Rust side, it should not be possible to call the default
123/// implementation. This is done to ensure that we call the vtable methods
124/// through the C vtable, and not through the Rust vtable. Therefore, the
125/// default implementation should call `build_error!`, which prevents
126/// calls to this function at compile time:
127///
128/// ```compile_fail
129/// # // Intentionally missing `use`s to simplify `rusttest`.
130/// build_error!(VTABLE_DEFAULT_ERROR)
131/// ```
132///
133/// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`].
134///
135/// This macro should not be used when all functions are required.
136///
137/// # Examples
138///
139/// ```
140/// use kernel::error::VTABLE_DEFAULT_ERROR;
141/// use kernel::prelude::*;
142///
143/// // Declares a `#[vtable]` trait
144/// #[vtable]
145/// pub trait Operations: Send + Sync + Sized {
146///     fn foo(&self) -> Result<()> {
147///         build_error!(VTABLE_DEFAULT_ERROR)
148///     }
149///
150///     fn bar(&self) -> Result<()> {
151///         build_error!(VTABLE_DEFAULT_ERROR)
152///     }
153/// }
154///
155/// struct Foo;
156///
157/// // Implements the `#[vtable]` trait
158/// #[vtable]
159/// impl Operations for Foo {
160///     fn foo(&self) -> Result<()> {
161/// #        Err(EINVAL)
162///         // ...
163///     }
164/// }
165///
166/// assert_eq!(<Foo as Operations>::HAS_FOO, true);
167/// assert_eq!(<Foo as Operations>::HAS_BAR, false);
168/// ```
169///
170/// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html
171#[proc_macro_attribute]
172pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
173    vtable::vtable(attr, ts)
174}
175
176/// Export a function so that C code can call it via a header file.
177///
178/// Functions exported using this macro can be called from C code using the declaration in the
179/// appropriate header file. It should only be used in cases where C calls the function through a
180/// header file; cases where C calls into Rust via a function pointer in a vtable (such as
181/// `file_operations`) should not use this macro.
182///
183/// This macro has the following effect:
184///
185/// * Disables name mangling for this function.
186/// * Verifies at compile-time that the function signature matches the declaration in the header
187///   file.
188///
189/// You must declare the signature of the Rust function in a header file that is included by
190/// `rust/bindings/bindings_helper.h`.
191///
192/// This macro is *not* the same as the C macros `EXPORT_SYMBOL_*`. All Rust symbols are currently
193/// automatically exported with `EXPORT_SYMBOL_GPL`.
194#[proc_macro_attribute]
195pub fn export(attr: TokenStream, ts: TokenStream) -> TokenStream {
196    export::export(attr, ts)
197}
198
199/// Concatenate two identifiers.
200///
201/// This is useful in macros that need to declare or reference items with names
202/// starting with a fixed prefix and ending in a user specified name. The resulting
203/// identifier has the span of the second argument.
204///
205/// # Examples
206///
207/// ```
208/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
209/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
210/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
211/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
212/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
213/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
214/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
215/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
216/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
217/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
218/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
219/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
220/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
221/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
222/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
223/// use kernel::macros::concat_idents;
224///
225/// macro_rules! pub_no_prefix {
226///     ($prefix:ident, $($newname:ident),+) => {
227///         $(pub(crate) const $newname: u32 = concat_idents!($prefix, $newname);)+
228///     };
229/// }
230///
231/// pub_no_prefix!(
232///     binder_driver_return_protocol_,
233///     BR_OK,
234///     BR_ERROR,
235///     BR_TRANSACTION,
236///     BR_REPLY,
237///     BR_DEAD_REPLY,
238///     BR_TRANSACTION_COMPLETE,
239///     BR_INCREFS,
240///     BR_ACQUIRE,
241///     BR_RELEASE,
242///     BR_DECREFS,
243///     BR_NOOP,
244///     BR_SPAWN_LOOPER,
245///     BR_DEAD_BINDER,
246///     BR_CLEAR_DEATH_NOTIFICATION_DONE,
247///     BR_FAILED_REPLY
248/// );
249///
250/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
251/// ```
252#[proc_macro]
253pub fn concat_idents(ts: TokenStream) -> TokenStream {
254    concat_idents::concat_idents(ts)
255}
256
257/// Paste identifiers together.
258///
259/// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a
260/// single identifier.
261///
262/// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and
263/// literals (lifetimes and documentation strings are not supported). There is a difference in
264/// supported modifiers as well.
265///
266/// # Example
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/// macro_rules! pub_no_prefix {
285///     ($prefix:ident, $($newname:ident),+) => {
286///         kernel::macros::paste! {
287///             $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+
288///         }
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///
314/// # Modifiers
315///
316/// For each identifier, it is possible to attach one or multiple modifiers to
317/// it.
318///
319/// Currently supported modifiers are:
320/// * `span`: change the span of concatenated identifier to the span of the specified token. By
321///   default the span of the `[< >]` group is used.
322/// * `lower`: change the identifier to lower case.
323/// * `upper`: change the identifier to upper case.
324///
325/// ```
326/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
327/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
328/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
329/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
330/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
331/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
332/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
333/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
334/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
335/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
336/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
337/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
338/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
339/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
340/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
341/// macro_rules! pub_no_prefix {
342///     ($prefix:ident, $($newname:ident),+) => {
343///         kernel::macros::paste! {
344///             $(pub(crate) const fn [<$newname:lower:span>]() -> u32 { [<$prefix $newname:span>] })+
345///         }
346///     };
347/// }
348///
349/// pub_no_prefix!(
350///     binder_driver_return_protocol_,
351///     BR_OK,
352///     BR_ERROR,
353///     BR_TRANSACTION,
354///     BR_REPLY,
355///     BR_DEAD_REPLY,
356///     BR_TRANSACTION_COMPLETE,
357///     BR_INCREFS,
358///     BR_ACQUIRE,
359///     BR_RELEASE,
360///     BR_DECREFS,
361///     BR_NOOP,
362///     BR_SPAWN_LOOPER,
363///     BR_DEAD_BINDER,
364///     BR_CLEAR_DEATH_NOTIFICATION_DONE,
365///     BR_FAILED_REPLY
366/// );
367///
368/// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK);
369/// ```
370///
371/// # Literals
372///
373/// Literals can also be concatenated with other identifiers:
374///
375/// ```
376/// macro_rules! create_numbered_fn {
377///     ($name:literal, $val:literal) => {
378///         kernel::macros::paste! {
379///             fn [<some_ $name _fn $val>]() -> u32 { $val }
380///         }
381///     };
382/// }
383///
384/// create_numbered_fn!("foo", 100);
385///
386/// assert_eq!(some_foo_fn100(), 100)
387/// ```
388///
389/// [`paste`]: https://docs.rs/paste/
390#[proc_macro]
391pub fn paste(input: TokenStream) -> TokenStream {
392    let mut tokens = input.into_iter().collect();
393    paste::expand(&mut tokens);
394    tokens.into_iter().collect()
395}
396
397/// Registers a KUnit test suite and its test cases using a user-space like syntax.
398///
399/// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module
400/// is ignored.
401///
402/// # Examples
403///
404/// ```ignore
405/// # use macros::kunit_tests;
406/// #[kunit_tests(kunit_test_suit_name)]
407/// mod tests {
408///     #[test]
409///     fn foo() {
410///         assert_eq!(1, 1);
411///     }
412///
413///     #[test]
414///     fn bar() {
415///         assert_eq!(2, 2);
416///     }
417/// }
418/// ```
419#[proc_macro_attribute]
420pub fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
421    kunit::kunit_tests(attr, ts)
422}
macros/lib.rs

macros/
lib.rs
