Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2
3//! Crate for all kernel procedural macros.
4
5#[macro_use]
6mod quote;
7mod concat_idents;
8mod helpers;
9mod module;
10mod paste;
11mod pin_data;
12mod pinned_drop;
13mod vtable;
14mod zeroable;
15
16use 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/// }
39///
40/// struct MyModule;
41///
42/// impl kernel::Module for MyModule {
43/// fn init() -> Result<Self> {
44/// // If the parameter is writeable, then the kparam lock must be
45/// // taken to read the parameter:
46/// {
47/// let lock = THIS_MODULE.kernel_param_lock();
48/// pr_info!("i32 param is: {}\n", writeable_i32.read(&lock));
49/// }
50/// // If the parameter is read only, it can be read without locking
51/// // the kernel parameters:
52/// pr_info!("i32 param is: {}\n", my_i32.read());
53/// Ok(Self)
54/// }
55/// }
56/// ```
57///
58/// # Supported argument types
59/// - `type`: type which implements the [`Module`] trait (required).
60/// - `name`: byte array of the name of the kernel module (required).
61/// - `author`: byte array of the author of the kernel module.
62/// - `description`: byte array of the description of the kernel module.
63/// - `license`: byte array of the license of the kernel module (required).
64/// - `alias`: byte array of alias name of the kernel module.
65#[proc_macro]
66pub fn module(ts: TokenStream) -> TokenStream {
67 module::module(ts)
68}
69
70/// Declares or implements a vtable trait.
71///
72/// Linux's use of pure vtables is very close to Rust traits, but they differ
73/// in how unimplemented functions are represented. In Rust, traits can provide
74/// default implementation for all non-required methods (and the default
75/// implementation could just return `Error::EINVAL`); Linux typically use C
76/// `NULL` pointers to represent these functions.
77///
78/// This attribute closes that gap. A trait can be annotated with the
79/// `#[vtable]` attribute. Implementers of the trait will then also have to
80/// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*`
81/// associated constant bool for each method in the trait that is set to true if
82/// the implementer has overridden the associated method.
83///
84/// For a trait method to be optional, it must have a default implementation.
85/// This is also the case for traits annotated with `#[vtable]`, but in this
86/// case the default implementation will never be executed. The reason for this
87/// is that the functions will be called through function pointers installed in
88/// C side vtables. When an optional method is not implemented on a `#[vtable]`
89/// trait, a NULL entry is installed in the vtable. Thus the default
90/// implementation is never called. Since these traits are not designed to be
91/// used on the Rust side, it should not be possible to call the default
92/// implementation. This is done to ensure that we call the vtable methods
93/// through the C vtable, and not through the Rust vtable. Therefore, the
94/// default implementation should call `kernel::build_error`, which prevents
95/// calls to this function at compile time:
96///
97/// ```compile_fail
98/// # use kernel::error::VTABLE_DEFAULT_ERROR;
99/// kernel::build_error(VTABLE_DEFAULT_ERROR)
100/// ```
101///
102/// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`].
103///
104/// This macro should not be used when all functions are required.
105///
106/// # Examples
107///
108/// ```ignore
109/// use kernel::error::VTABLE_DEFAULT_ERROR;
110/// use kernel::prelude::*;
111///
112/// // Declares a `#[vtable]` trait
113/// #[vtable]
114/// pub trait Operations: Send + Sync + Sized {
115/// fn foo(&self) -> Result<()> {
116/// kernel::build_error(VTABLE_DEFAULT_ERROR)
117/// }
118///
119/// fn bar(&self) -> Result<()> {
120/// kernel::build_error(VTABLE_DEFAULT_ERROR)
121/// }
122/// }
123///
124/// struct Foo;
125///
126/// // Implements the `#[vtable]` trait
127/// #[vtable]
128/// impl Operations for Foo {
129/// fn foo(&self) -> Result<()> {
130/// # Err(EINVAL)
131/// // ...
132/// }
133/// }
134///
135/// assert_eq!(<Foo as Operations>::HAS_FOO, true);
136/// assert_eq!(<Foo as Operations>::HAS_BAR, false);
137/// ```
138///
139/// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html
140#[proc_macro_attribute]
141pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
142 vtable::vtable(attr, ts)
143}
144
145/// Concatenate two identifiers.
146///
147/// This is useful in macros that need to declare or reference items with names
148/// starting with a fixed prefix and ending in a user specified name. The resulting
149/// identifier has the span of the second argument.
150///
151/// # Examples
152///
153/// ```ignore
154/// use kernel::macro::concat_idents;
155///
156/// macro_rules! pub_no_prefix {
157/// ($prefix:ident, $($newname:ident),+) => {
158/// $(pub(crate) const $newname: u32 = kernel::macros::concat_idents!($prefix, $newname);)+
159/// };
160/// }
161///
162/// pub_no_prefix!(
163/// binder_driver_return_protocol_,
164/// BR_OK,
165/// BR_ERROR,
166/// BR_TRANSACTION,
167/// BR_REPLY,
168/// BR_DEAD_REPLY,
169/// BR_TRANSACTION_COMPLETE,
170/// BR_INCREFS,
171/// BR_ACQUIRE,
172/// BR_RELEASE,
173/// BR_DECREFS,
174/// BR_NOOP,
175/// BR_SPAWN_LOOPER,
176/// BR_DEAD_BINDER,
177/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
178/// BR_FAILED_REPLY
179/// );
180///
181/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
182/// ```
183#[proc_macro]
184pub fn concat_idents(ts: TokenStream) -> TokenStream {
185 concat_idents::concat_idents(ts)
186}
187
188/// Used to specify the pinning information of the fields of a struct.
189///
190/// This is somewhat similar in purpose as
191/// [pin-project-lite](https://crates.io/crates/pin-project-lite).
192/// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each
193/// field you want to structurally pin.
194///
195/// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`,
196/// then `#[pin]` directs the type of initializer that is required.
197///
198/// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this
199/// macro, and change your `Drop` implementation to `PinnedDrop` annotated with
200/// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care.
201///
202/// # Examples
203///
204/// ```rust,ignore
205/// #[pin_data]
206/// struct DriverData {
207/// #[pin]
208/// queue: Mutex<Vec<Command>>,
209/// buf: Box<[u8; 1024 * 1024]>,
210/// }
211/// ```
212///
213/// ```rust,ignore
214/// #[pin_data(PinnedDrop)]
215/// struct DriverData {
216/// #[pin]
217/// queue: Mutex<Vec<Command>>,
218/// buf: Box<[u8; 1024 * 1024]>,
219/// raw_info: *mut Info,
220/// }
221///
222/// #[pinned_drop]
223/// impl PinnedDrop for DriverData {
224/// fn drop(self: Pin<&mut Self>) {
225/// unsafe { bindings::destroy_info(self.raw_info) };
226/// }
227/// }
228/// ```
229///
230/// [`pin_init!`]: ../kernel/macro.pin_init.html
231// ^ cannot use direct link, since `kernel` is not a dependency of `macros`.
232#[proc_macro_attribute]
233pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream {
234 pin_data::pin_data(inner, item)
235}
236
237/// Used to implement `PinnedDrop` safely.
238///
239/// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`.
240///
241/// # Examples
242///
243/// ```rust,ignore
244/// #[pin_data(PinnedDrop)]
245/// struct DriverData {
246/// #[pin]
247/// queue: Mutex<Vec<Command>>,
248/// buf: Box<[u8; 1024 * 1024]>,
249/// raw_info: *mut Info,
250/// }
251///
252/// #[pinned_drop]
253/// impl PinnedDrop for DriverData {
254/// fn drop(self: Pin<&mut Self>) {
255/// unsafe { bindings::destroy_info(self.raw_info) };
256/// }
257/// }
258/// ```
259#[proc_macro_attribute]
260pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
261 pinned_drop::pinned_drop(args, input)
262}
263
264/// Paste identifiers together.
265///
266/// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a
267/// single identifier.
268///
269/// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and
270/// literals (lifetimes and documentation strings are not supported). There is a difference in
271/// supported modifiers as well.
272///
273/// # Example
274///
275/// ```ignore
276/// use kernel::macro::paste;
277///
278/// macro_rules! pub_no_prefix {
279/// ($prefix:ident, $($newname:ident),+) => {
280/// paste! {
281/// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+
282/// }
283/// };
284/// }
285///
286/// pub_no_prefix!(
287/// binder_driver_return_protocol_,
288/// BR_OK,
289/// BR_ERROR,
290/// BR_TRANSACTION,
291/// BR_REPLY,
292/// BR_DEAD_REPLY,
293/// BR_TRANSACTION_COMPLETE,
294/// BR_INCREFS,
295/// BR_ACQUIRE,
296/// BR_RELEASE,
297/// BR_DECREFS,
298/// BR_NOOP,
299/// BR_SPAWN_LOOPER,
300/// BR_DEAD_BINDER,
301/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
302/// BR_FAILED_REPLY
303/// );
304///
305/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
306/// ```
307///
308/// # Modifiers
309///
310/// For each identifier, it is possible to attach one or multiple modifiers to
311/// it.
312///
313/// Currently supported modifiers are:
314/// * `span`: change the span of concatenated identifier to the span of the specified token. By
315/// default the span of the `[< >]` group is used.
316/// * `lower`: change the identifier to lower case.
317/// * `upper`: change the identifier to upper case.
318///
319/// ```ignore
320/// use kernel::macro::paste;
321///
322/// macro_rules! pub_no_prefix {
323/// ($prefix:ident, $($newname:ident),+) => {
324/// kernel::macros::paste! {
325/// $(pub(crate) const fn [<$newname:lower:span>]: u32 = [<$prefix $newname:span>];)+
326/// }
327/// };
328/// }
329///
330/// pub_no_prefix!(
331/// binder_driver_return_protocol_,
332/// BR_OK,
333/// BR_ERROR,
334/// BR_TRANSACTION,
335/// BR_REPLY,
336/// BR_DEAD_REPLY,
337/// BR_TRANSACTION_COMPLETE,
338/// BR_INCREFS,
339/// BR_ACQUIRE,
340/// BR_RELEASE,
341/// BR_DECREFS,
342/// BR_NOOP,
343/// BR_SPAWN_LOOPER,
344/// BR_DEAD_BINDER,
345/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
346/// BR_FAILED_REPLY
347/// );
348///
349/// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK);
350/// ```
351///
352/// # Literals
353///
354/// Literals can also be concatenated with other identifiers:
355///
356/// ```ignore
357/// macro_rules! create_numbered_fn {
358/// ($name:literal, $val:literal) => {
359/// kernel::macros::paste! {
360/// fn [<some_ $name _fn $val>]() -> u32 { $val }
361/// }
362/// };
363/// }
364///
365/// create_numbered_fn!("foo", 100);
366///
367/// assert_eq!(some_foo_fn100(), 100)
368/// ```
369///
370/// [`paste`]: https://docs.rs/paste/
371#[proc_macro]
372pub fn paste(input: TokenStream) -> TokenStream {
373 let mut tokens = input.into_iter().collect();
374 paste::expand(&mut tokens);
375 tokens.into_iter().collect()
376}
377
378/// Derives the [`Zeroable`] trait for the given struct.
379///
380/// This can only be used for structs where every field implements the [`Zeroable`] trait.
381///
382/// # Examples
383///
384/// ```rust,ignore
385/// #[derive(Zeroable)]
386/// pub struct DriverData {
387/// id: i64,
388/// buf_ptr: *mut u8,
389/// len: usize,
390/// }
391/// ```
392#[proc_macro_derive(Zeroable)]
393pub fn derive_zeroable(input: TokenStream) -> TokenStream {
394 zeroable::derive(input)
395}