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 fmt;
19mod helpers;
20mod kunit;
21mod module;
22mod paste;
23mod vtable;
24
25use 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/// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h)
33///
34/// [`Module`]: ../kernel/trait.Module.html
35///
36/// # Examples
37///
38/// ```
39/// use kernel::prelude::*;
40///
41/// module!{
42///     type: MyModule,
43///     name: "my_kernel_module",
44///     authors: ["Rust for Linux Contributors"],
45///     description: "My very own kernel module!",
46///     license: "GPL",
47///     alias: ["alternate_module_name"],
48/// }
49///
50/// struct MyModule(i32);
51///
52/// impl kernel::Module for MyModule {
53///     fn init(_module: &'static ThisModule) -> Result<Self> {
54///         let foo: i32 = 42;
55///         pr_info!("I contain:  {}\n", foo);
56///         Ok(Self(foo))
57///     }
58/// }
59/// # fn main() {}
60/// ```
61///
62/// ## Firmware
63///
64/// The following example shows how to declare a kernel module that needs
65/// to load binary firmware files. You need to specify the file names of
66/// the firmware in the `firmware` field. The information is embedded
67/// in the `modinfo` section of the kernel module. For example, a tool to
68/// build an initramfs uses this information to put the firmware files into
69/// the initramfs image.
70///
71/// ```
72/// use kernel::prelude::*;
73///
74/// module!{
75///     type: MyDeviceDriverModule,
76///     name: "my_device_driver_module",
77///     authors: ["Rust for Linux Contributors"],
78///     description: "My device driver requires firmware",
79///     license: "GPL",
80///     firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"],
81/// }
82///
83/// struct MyDeviceDriverModule;
84///
85/// impl kernel::Module for MyDeviceDriverModule {
86///     fn init(_module: &'static ThisModule) -> Result<Self> {
87///         Ok(Self)
88///     }
89/// }
90/// # fn main() {}
91/// ```
92///
93/// # Supported argument types
94///   - `type`: type which implements the [`Module`] trait (required).
95///   - `name`: ASCII string literal of the name of the kernel module (required).
96///   - `authors`: array of ASCII string literals of the authors of the kernel module.
97///   - `description`: string literal of the description of the kernel module.
98///   - `license`: ASCII string literal of the license of the kernel module (required).
99///   - `alias`: array of ASCII string literals of the alias names of the kernel module.
100///   - `firmware`: array of ASCII string literals of the firmware files of
101///     the kernel module.
102#[proc_macro]
103pub fn module(ts: TokenStream) -> TokenStream {
104    module::module(ts)
105}
106
107/// Declares or implements a vtable trait.
108///
109/// Linux's use of pure vtables is very close to Rust traits, but they differ
110/// in how unimplemented functions are represented. In Rust, traits can provide
111/// default implementation for all non-required methods (and the default
112/// implementation could just return `Error::EINVAL`); Linux typically use C
113/// `NULL` pointers to represent these functions.
114///
115/// This attribute closes that gap. A trait can be annotated with the
116/// `#[vtable]` attribute. Implementers of the trait will then also have to
117/// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*`
118/// associated constant bool for each method in the trait that is set to true if
119/// the implementer has overridden the associated method.
120///
121/// For a trait method to be optional, it must have a default implementation.
122/// This is also the case for traits annotated with `#[vtable]`, but in this
123/// case the default implementation will never be executed. The reason for this
124/// is that the functions will be called through function pointers installed in
125/// C side vtables. When an optional method is not implemented on a `#[vtable]`
126/// trait, a NULL entry is installed in the vtable. Thus the default
127/// implementation is never called. Since these traits are not designed to be
128/// used on the Rust side, it should not be possible to call the default
129/// implementation. This is done to ensure that we call the vtable methods
130/// through the C vtable, and not through the Rust vtable. Therefore, the
131/// default implementation should call `build_error!`, which prevents
132/// calls to this function at compile time:
133///
134/// ```compile_fail
135/// # // Intentionally missing `use`s to simplify `rusttest`.
136/// build_error!(VTABLE_DEFAULT_ERROR)
137/// ```
138///
139/// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`].
140///
141/// This macro should not be used when all functions are required.
142///
143/// # Examples
144///
145/// ```
146/// use kernel::error::VTABLE_DEFAULT_ERROR;
147/// use kernel::prelude::*;
148///
149/// // Declares a `#[vtable]` trait
150/// #[vtable]
151/// pub trait Operations: Send + Sync + Sized {
152///     fn foo(&self) -> Result<()> {
153///         build_error!(VTABLE_DEFAULT_ERROR)
154///     }
155///
156///     fn bar(&self) -> Result<()> {
157///         build_error!(VTABLE_DEFAULT_ERROR)
158///     }
159/// }
160///
161/// struct Foo;
162///
163/// // Implements the `#[vtable]` trait
164/// #[vtable]
165/// impl Operations for Foo {
166///     fn foo(&self) -> Result<()> {
167/// #        Err(EINVAL)
168///         // ...
169///     }
170/// }
171///
172/// assert_eq!(<Foo as Operations>::HAS_FOO, true);
173/// assert_eq!(<Foo as Operations>::HAS_BAR, false);
174/// ```
175///
176/// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html
177#[proc_macro_attribute]
178pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
179    vtable::vtable(attr, ts)
180}
181
182/// Export a function so that C code can call it via a header file.
183///
184/// Functions exported using this macro can be called from C code using the declaration in the
185/// appropriate header file. It should only be used in cases where C calls the function through a
186/// header file; cases where C calls into Rust via a function pointer in a vtable (such as
187/// `file_operations`) should not use this macro.
188///
189/// This macro has the following effect:
190///
191/// * Disables name mangling for this function.
192/// * Verifies at compile-time that the function signature matches the declaration in the header
193///   file.
194///
195/// You must declare the signature of the Rust function in a header file that is included by
196/// `rust/bindings/bindings_helper.h`.
197///
198/// This macro is *not* the same as the C macros `EXPORT_SYMBOL_*`. All Rust symbols are currently
199/// automatically exported with `EXPORT_SYMBOL_GPL`.
200#[proc_macro_attribute]
201pub fn export(attr: TokenStream, ts: TokenStream) -> TokenStream {
202    export::export(attr, ts)
203}
204
205/// Like [`core::format_args!`], but automatically wraps arguments in [`kernel::fmt::Adapter`].
206///
207/// This macro allows generating `fmt::Arguments` while ensuring that each argument is wrapped with
208/// `::kernel::fmt::Adapter`, which customizes formatting behavior for kernel logging.
209///
210/// Named arguments used in the format string (e.g. `{foo}`) are detected and resolved from local
211/// bindings. All positional and named arguments are automatically wrapped.
212///
213/// This macro is an implementation detail of other kernel logging macros like [`pr_info!`] and
214/// should not typically be used directly.
215///
216/// [`kernel::fmt::Adapter`]: ../kernel/fmt/struct.Adapter.html
217/// [`pr_info!`]: ../kernel/macro.pr_info.html
218#[proc_macro]
219pub fn fmt(input: TokenStream) -> TokenStream {
220    fmt::fmt(input)
221}
222
223/// Concatenate two identifiers.
224///
225/// This is useful in macros that need to declare or reference items with names
226/// starting with a fixed prefix and ending in a user specified name. The resulting
227/// identifier has the span of the second argument.
228///
229/// # Examples
230///
231/// ```
232/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
233/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
234/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
235/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
236/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
237/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
238/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
239/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
240/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
241/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
242/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
243/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
244/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
245/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
246/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
247/// use kernel::macros::concat_idents;
248///
249/// macro_rules! pub_no_prefix {
250///     ($prefix:ident, $($newname:ident),+) => {
251///         $(pub(crate) const $newname: u32 = concat_idents!($prefix, $newname);)+
252///     };
253/// }
254///
255/// pub_no_prefix!(
256///     binder_driver_return_protocol_,
257///     BR_OK,
258///     BR_ERROR,
259///     BR_TRANSACTION,
260///     BR_REPLY,
261///     BR_DEAD_REPLY,
262///     BR_TRANSACTION_COMPLETE,
263///     BR_INCREFS,
264///     BR_ACQUIRE,
265///     BR_RELEASE,
266///     BR_DECREFS,
267///     BR_NOOP,
268///     BR_SPAWN_LOOPER,
269///     BR_DEAD_BINDER,
270///     BR_CLEAR_DEATH_NOTIFICATION_DONE,
271///     BR_FAILED_REPLY
272/// );
273///
274/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
275/// ```
276#[proc_macro]
277pub fn concat_idents(ts: TokenStream) -> TokenStream {
278    concat_idents::concat_idents(ts)
279}
280
281/// Paste identifiers together.
282///
283/// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a
284/// single identifier.
285///
286/// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and
287/// literals (lifetimes and documentation strings are not supported). There is a difference in
288/// supported modifiers as well.
289///
290/// # Examples
291///
292/// ```
293/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
294/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
295/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
296/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
297/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
298/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
299/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
300/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
301/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
302/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
303/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
304/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
305/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
306/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
307/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
308/// macro_rules! pub_no_prefix {
309///     ($prefix:ident, $($newname:ident),+) => {
310///         ::kernel::macros::paste! {
311///             $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+
312///         }
313///     };
314/// }
315///
316/// pub_no_prefix!(
317///     binder_driver_return_protocol_,
318///     BR_OK,
319///     BR_ERROR,
320///     BR_TRANSACTION,
321///     BR_REPLY,
322///     BR_DEAD_REPLY,
323///     BR_TRANSACTION_COMPLETE,
324///     BR_INCREFS,
325///     BR_ACQUIRE,
326///     BR_RELEASE,
327///     BR_DECREFS,
328///     BR_NOOP,
329///     BR_SPAWN_LOOPER,
330///     BR_DEAD_BINDER,
331///     BR_CLEAR_DEATH_NOTIFICATION_DONE,
332///     BR_FAILED_REPLY
333/// );
334///
335/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
336/// ```
337///
338/// # Modifiers
339///
340/// For each identifier, it is possible to attach one or multiple modifiers to
341/// it.
342///
343/// Currently supported modifiers are:
344/// * `span`: change the span of concatenated identifier to the span of the specified token. By
345///   default the span of the `[< >]` group is used.
346/// * `lower`: change the identifier to lower case.
347/// * `upper`: change the identifier to upper case.
348///
349/// ```
350/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
351/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
352/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
353/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
354/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
355/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
356/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
357/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
358/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
359/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
360/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
361/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
362/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
363/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
364/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
365/// macro_rules! pub_no_prefix {
366///     ($prefix:ident, $($newname:ident),+) => {
367///         ::kernel::macros::paste! {
368///             $(pub(crate) const fn [<$newname:lower:span>]() -> u32 { [<$prefix $newname:span>] })+
369///         }
370///     };
371/// }
372///
373/// pub_no_prefix!(
374///     binder_driver_return_protocol_,
375///     BR_OK,
376///     BR_ERROR,
377///     BR_TRANSACTION,
378///     BR_REPLY,
379///     BR_DEAD_REPLY,
380///     BR_TRANSACTION_COMPLETE,
381///     BR_INCREFS,
382///     BR_ACQUIRE,
383///     BR_RELEASE,
384///     BR_DECREFS,
385///     BR_NOOP,
386///     BR_SPAWN_LOOPER,
387///     BR_DEAD_BINDER,
388///     BR_CLEAR_DEATH_NOTIFICATION_DONE,
389///     BR_FAILED_REPLY
390/// );
391///
392/// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK);
393/// ```
394///
395/// # Literals
396///
397/// Literals can also be concatenated with other identifiers:
398///
399/// ```
400/// macro_rules! create_numbered_fn {
401///     ($name:literal, $val:literal) => {
402///         ::kernel::macros::paste! {
403///             fn [<some_ $name _fn $val>]() -> u32 { $val }
404///         }
405///     };
406/// }
407///
408/// create_numbered_fn!("foo", 100);
409///
410/// assert_eq!(some_foo_fn100(), 100)
411/// ```
412///
413/// [`paste`]: https://docs.rs/paste/
414#[proc_macro]
415pub fn paste(input: TokenStream) -> TokenStream {
416    let mut tokens = input.into_iter().collect();
417    paste::expand(&mut tokens);
418    tokens.into_iter().collect()
419}
420
421/// Registers a KUnit test suite and its test cases using a user-space like syntax.
422///
423/// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module
424/// is ignored.
425///
426/// # Examples
427///
428/// ```ignore
429/// # use kernel::prelude::*;
430/// #[kunit_tests(kunit_test_suit_name)]
431/// mod tests {
432///     #[test]
433///     fn foo() {
434///         assert_eq!(1, 1);
435///     }
436///
437///     #[test]
438///     fn bar() {
439///         assert_eq!(2, 2);
440///     }
441/// }
442/// ```
443#[proc_macro_attribute]
444pub fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
445    kunit::kunit_tests(attr, ts)
446}
macros/lib.rs

macros/
lib.rs
