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// 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]
15mod quote;
16mod concat_idents;
17mod export;
18mod helpers;
19mod kunit;
20mod module;
21mod paste;
22mod vtable;
23
24use proc_macro::TokenStream;
25
26/// Declares a kernel module.
27///
28/// The `type` argument should be a type which implements the [`Module`]
29/// trait. Also accepts various forms of kernel metadata.
30///
31/// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h)
32///
33/// [`Module`]: ../kernel/trait.Module.html
34///
35/// # Examples
36///
37/// ```
38/// use kernel::prelude::*;
39///
40/// module!{
41///     type: MyModule,
42///     name: "my_kernel_module",
43///     authors: ["Rust for Linux Contributors"],
44///     description: "My very own kernel module!",
45///     license: "GPL",
46///     alias: ["alternate_module_name"],
47/// }
48///
49/// struct MyModule(i32);
50///
51/// impl kernel::Module for MyModule {
52///     fn init(_module: &'static ThisModule) -> Result<Self> {
53///         let foo: i32 = 42;
54///         pr_info!("I contain:  {}\n", foo);
55///         Ok(Self(foo))
56///     }
57/// }
58/// # fn main() {}
59/// ```
60///
61/// ## Firmware
62///
63/// The following example shows how to declare a kernel module that needs
64/// to load binary firmware files. You need to specify the file names of
65/// the firmware in the `firmware` field. The information is embedded
66/// in the `modinfo` section of the kernel module. For example, a tool to
67/// build an initramfs uses this information to put the firmware files into
68/// the initramfs image.
69///
70/// ```
71/// use kernel::prelude::*;
72///
73/// module!{
74///     type: MyDeviceDriverModule,
75///     name: "my_device_driver_module",
76///     authors: ["Rust for Linux Contributors"],
77///     description: "My device driver requires firmware",
78///     license: "GPL",
79///     firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"],
80/// }
81///
82/// struct MyDeviceDriverModule;
83///
84/// impl kernel::Module for MyDeviceDriverModule {
85///     fn init(_module: &'static ThisModule) -> Result<Self> {
86///         Ok(Self)
87///     }
88/// }
89/// # fn main() {}
90/// ```
91///
92/// # Supported argument types
93///   - `type`: type which implements the [`Module`] trait (required).
94///   - `name`: ASCII string literal of the name of the kernel module (required).
95///   - `authors`: array of ASCII string literals of the authors of the kernel module.
96///   - `description`: string literal of the description of the kernel module.
97///   - `license`: ASCII string literal of the license of the kernel module (required).
98///   - `alias`: array of ASCII string literals of the alias names of the kernel module.
99///   - `firmware`: array of ASCII string literals of the firmware files of
100///     the kernel module.
101#[proc_macro]
102pub fn module(ts: TokenStream) -> TokenStream {
103    module::module(ts)
104}
105
106/// Declares or implements a vtable trait.
107///
108/// Linux's use of pure vtables is very close to Rust traits, but they differ
109/// in how unimplemented functions are represented. In Rust, traits can provide
110/// default implementation for all non-required methods (and the default
111/// implementation could just return `Error::EINVAL`); Linux typically use C
112/// `NULL` pointers to represent these functions.
113///
114/// This attribute closes that gap. A trait can be annotated with the
115/// `#[vtable]` attribute. Implementers of the trait will then also have to
116/// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*`
117/// associated constant bool for each method in the trait that is set to true if
118/// the implementer has overridden the associated method.
119///
120/// For a trait method to be optional, it must have a default implementation.
121/// This is also the case for traits annotated with `#[vtable]`, but in this
122/// case the default implementation will never be executed. The reason for this
123/// is that the functions will be called through function pointers installed in
124/// C side vtables. When an optional method is not implemented on a `#[vtable]`
125/// trait, a NULL entry is installed in the vtable. Thus the default
126/// implementation is never called. Since these traits are not designed to be
127/// used on the Rust side, it should not be possible to call the default
128/// implementation. This is done to ensure that we call the vtable methods
129/// through the C vtable, and not through the Rust vtable. Therefore, the
130/// default implementation should call `build_error!`, which prevents
131/// calls to this function at compile time:
132///
133/// ```compile_fail
134/// # // Intentionally missing `use`s to simplify `rusttest`.
135/// build_error!(VTABLE_DEFAULT_ERROR)
136/// ```
137///
138/// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`].
139///
140/// This macro should not be used when all functions are required.
141///
142/// # Examples
143///
144/// ```
145/// use kernel::error::VTABLE_DEFAULT_ERROR;
146/// use kernel::prelude::*;
147///
148/// // Declares a `#[vtable]` trait
149/// #[vtable]
150/// pub trait Operations: Send + Sync + Sized {
151///     fn foo(&self) -> Result<()> {
152///         build_error!(VTABLE_DEFAULT_ERROR)
153///     }
154///
155///     fn bar(&self) -> Result<()> {
156///         build_error!(VTABLE_DEFAULT_ERROR)
157///     }
158/// }
159///
160/// struct Foo;
161///
162/// // Implements the `#[vtable]` trait
163/// #[vtable]
164/// impl Operations for Foo {
165///     fn foo(&self) -> Result<()> {
166/// #        Err(EINVAL)
167///         // ...
168///     }
169/// }
170///
171/// assert_eq!(<Foo as Operations>::HAS_FOO, true);
172/// assert_eq!(<Foo as Operations>::HAS_BAR, false);
173/// ```
174///
175/// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html
176#[proc_macro_attribute]
177pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
178    vtable::vtable(attr, ts)
179}
180
181/// Export a function so that C code can call it via a header file.
182///
183/// Functions exported using this macro can be called from C code using the declaration in the
184/// appropriate header file. It should only be used in cases where C calls the function through a
185/// header file; cases where C calls into Rust via a function pointer in a vtable (such as
186/// `file_operations`) should not use this macro.
187///
188/// This macro has the following effect:
189///
190/// * Disables name mangling for this function.
191/// * Verifies at compile-time that the function signature matches the declaration in the header
192///   file.
193///
194/// You must declare the signature of the Rust function in a header file that is included by
195/// `rust/bindings/bindings_helper.h`.
196///
197/// This macro is *not* the same as the C macros `EXPORT_SYMBOL_*`. All Rust symbols are currently
198/// automatically exported with `EXPORT_SYMBOL_GPL`.
199#[proc_macro_attribute]
200pub fn export(attr: TokenStream, ts: TokenStream) -> TokenStream {
201    export::export(attr, ts)
202}
203
204/// Concatenate two identifiers.
205///
206/// This is useful in macros that need to declare or reference items with names
207/// starting with a fixed prefix and ending in a user specified name. The resulting
208/// identifier has the span of the second argument.
209///
210/// # Examples
211///
212/// ```
213/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
214/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
215/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
216/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
217/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
218/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
219/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
220/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
221/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
222/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
223/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
224/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
225/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
226/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
227/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
228/// use kernel::macros::concat_idents;
229///
230/// macro_rules! pub_no_prefix {
231///     ($prefix:ident, $($newname:ident),+) => {
232///         $(pub(crate) const $newname: u32 = concat_idents!($prefix, $newname);)+
233///     };
234/// }
235///
236/// pub_no_prefix!(
237///     binder_driver_return_protocol_,
238///     BR_OK,
239///     BR_ERROR,
240///     BR_TRANSACTION,
241///     BR_REPLY,
242///     BR_DEAD_REPLY,
243///     BR_TRANSACTION_COMPLETE,
244///     BR_INCREFS,
245///     BR_ACQUIRE,
246///     BR_RELEASE,
247///     BR_DECREFS,
248///     BR_NOOP,
249///     BR_SPAWN_LOOPER,
250///     BR_DEAD_BINDER,
251///     BR_CLEAR_DEATH_NOTIFICATION_DONE,
252///     BR_FAILED_REPLY
253/// );
254///
255/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
256/// ```
257#[proc_macro]
258pub fn concat_idents(ts: TokenStream) -> TokenStream {
259    concat_idents::concat_idents(ts)
260}
261
262/// Paste identifiers together.
263///
264/// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a
265/// single identifier.
266///
267/// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and
268/// literals (lifetimes and documentation strings are not supported). There is a difference in
269/// supported modifiers as well.
270///
271/// # Examples
272///
273/// ```
274/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
275/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
276/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
277/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
278/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
279/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
280/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
281/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
282/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
283/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
284/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
285/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
286/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
287/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
288/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
289/// macro_rules! pub_no_prefix {
290///     ($prefix:ident, $($newname:ident),+) => {
291///         ::kernel::macros::paste! {
292///             $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+
293///         }
294///     };
295/// }
296///
297/// pub_no_prefix!(
298///     binder_driver_return_protocol_,
299///     BR_OK,
300///     BR_ERROR,
301///     BR_TRANSACTION,
302///     BR_REPLY,
303///     BR_DEAD_REPLY,
304///     BR_TRANSACTION_COMPLETE,
305///     BR_INCREFS,
306///     BR_ACQUIRE,
307///     BR_RELEASE,
308///     BR_DECREFS,
309///     BR_NOOP,
310///     BR_SPAWN_LOOPER,
311///     BR_DEAD_BINDER,
312///     BR_CLEAR_DEATH_NOTIFICATION_DONE,
313///     BR_FAILED_REPLY
314/// );
315///
316/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
317/// ```
318///
319/// # Modifiers
320///
321/// For each identifier, it is possible to attach one or multiple modifiers to
322/// it.
323///
324/// Currently supported modifiers are:
325/// * `span`: change the span of concatenated identifier to the span of the specified token. By
326///   default the span of the `[< >]` group is used.
327/// * `lower`: change the identifier to lower case.
328/// * `upper`: change the identifier to upper case.
329///
330/// ```
331/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
332/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
333/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
334/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
335/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
336/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
337/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
338/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
339/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
340/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
341/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
342/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
343/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
344/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
345/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
346/// macro_rules! pub_no_prefix {
347///     ($prefix:ident, $($newname:ident),+) => {
348///         ::kernel::macros::paste! {
349///             $(pub(crate) const fn [<$newname:lower:span>]() -> u32 { [<$prefix $newname:span>] })+
350///         }
351///     };
352/// }
353///
354/// pub_no_prefix!(
355///     binder_driver_return_protocol_,
356///     BR_OK,
357///     BR_ERROR,
358///     BR_TRANSACTION,
359///     BR_REPLY,
360///     BR_DEAD_REPLY,
361///     BR_TRANSACTION_COMPLETE,
362///     BR_INCREFS,
363///     BR_ACQUIRE,
364///     BR_RELEASE,
365///     BR_DECREFS,
366///     BR_NOOP,
367///     BR_SPAWN_LOOPER,
368///     BR_DEAD_BINDER,
369///     BR_CLEAR_DEATH_NOTIFICATION_DONE,
370///     BR_FAILED_REPLY
371/// );
372///
373/// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK);
374/// ```
375///
376/// # Literals
377///
378/// Literals can also be concatenated with other identifiers:
379///
380/// ```
381/// macro_rules! create_numbered_fn {
382///     ($name:literal, $val:literal) => {
383///         ::kernel::macros::paste! {
384///             fn [<some_ $name _fn $val>]() -> u32 { $val }
385///         }
386///     };
387/// }
388///
389/// create_numbered_fn!("foo", 100);
390///
391/// assert_eq!(some_foo_fn100(), 100)
392/// ```
393///
394/// [`paste`]: https://docs.rs/paste/
395#[proc_macro]
396pub fn paste(input: TokenStream) -> TokenStream {
397    let mut tokens = input.into_iter().collect();
398    paste::expand(&mut tokens);
399    tokens.into_iter().collect()
400}
401
402/// Registers a KUnit test suite and its test cases using a user-space like syntax.
403///
404/// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module
405/// is ignored.
406///
407/// # Examples
408///
409/// ```ignore
410/// # use kernel::prelude::*;
411/// #[kunit_tests(kunit_test_suit_name)]
412/// mod tests {
413///     #[test]
414///     fn foo() {
415///         assert_eq!(1, 1);
416///     }
417///
418///     #[test]
419///     fn bar() {
420///         assert_eq!(2, 2);
421///     }
422/// }
423/// ```
424#[proc_macro_attribute]
425pub fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
426    kunit::kunit_tests(attr, ts)
427}
macros/lib.rs

macros/
lib.rs
