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`](../../../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/// params: {
39/// my_i32: i32 {
40/// default: 42,
41/// permissions: 0o000,
42/// description: "Example of i32",
43/// },
44/// writeable_i32: i32 {
45/// default: 42,
46/// permissions: 0o644,
47/// description: "Example of i32",
48/// },
49/// },
50/// }
51///
52/// struct MyModule;
53///
54/// impl kernel::Module for MyModule {
55/// fn init() -> Result<Self> {
56/// // If the parameter is writeable, then the kparam lock must be
57/// // taken to read the parameter:
58/// {
59/// let lock = THIS_MODULE.kernel_param_lock();
60/// pr_info!("i32 param is: {}\n", writeable_i32.read(&lock));
61/// }
62/// // If the parameter is read only, it can be read without locking
63/// // the kernel parameters:
64/// pr_info!("i32 param is: {}\n", my_i32.read());
65/// Ok(Self)
66/// }
67/// }
68/// ```
69///
70/// # Supported argument types
71/// - `type`: type which implements the [`Module`] trait (required).
72/// - `name`: byte array of the name of the kernel module (required).
73/// - `author`: byte array of the author of the kernel module.
74/// - `description`: byte array of the description of the kernel module.
75/// - `license`: byte array of the license of the kernel module (required).
76/// - `alias`: byte array of alias name of the kernel module.
77#[proc_macro]
78pub fn module(ts: TokenStream) -> TokenStream {
79 module::module(ts)
80}
81
82/// Declares or implements a vtable trait.
83///
84/// Linux's use of pure vtables is very close to Rust traits, but they differ
85/// in how unimplemented functions are represented. In Rust, traits can provide
86/// default implementation for all non-required methods (and the default
87/// implementation could just return `Error::EINVAL`); Linux typically use C
88/// `NULL` pointers to represent these functions.
89///
90/// This attribute is intended to close the gap. Traits can be declared and
91/// implemented with the `#[vtable]` attribute, and a `HAS_*` associated constant
92/// will be generated for each method in the trait, indicating if the implementor
93/// has overridden a method.
94///
95/// This attribute is not needed if all methods are required.
96///
97/// # Examples
98///
99/// ```ignore
100/// use kernel::prelude::*;
101///
102/// // Declares a `#[vtable]` trait
103/// #[vtable]
104/// pub trait Operations: Send + Sync + Sized {
105/// fn foo(&self) -> Result<()> {
106/// Err(EINVAL)
107/// }
108///
109/// fn bar(&self) -> Result<()> {
110/// Err(EINVAL)
111/// }
112/// }
113///
114/// struct Foo;
115///
116/// // Implements the `#[vtable]` trait
117/// #[vtable]
118/// impl Operations for Foo {
119/// fn foo(&self) -> Result<()> {
120/// # Err(EINVAL)
121/// // ...
122/// }
123/// }
124///
125/// assert_eq!(<Foo as Operations>::HAS_FOO, true);
126/// assert_eq!(<Foo as Operations>::HAS_BAR, false);
127/// ```
128#[proc_macro_attribute]
129pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
130 vtable::vtable(attr, ts)
131}
132
133/// Concatenate two identifiers.
134///
135/// This is useful in macros that need to declare or reference items with names
136/// starting with a fixed prefix and ending in a user specified name. The resulting
137/// identifier has the span of the second argument.
138///
139/// # Examples
140///
141/// ```ignore
142/// use kernel::macro::concat_idents;
143///
144/// macro_rules! pub_no_prefix {
145/// ($prefix:ident, $($newname:ident),+) => {
146/// $(pub(crate) const $newname: u32 = kernel::macros::concat_idents!($prefix, $newname);)+
147/// };
148/// }
149///
150/// pub_no_prefix!(
151/// binder_driver_return_protocol_,
152/// BR_OK,
153/// BR_ERROR,
154/// BR_TRANSACTION,
155/// BR_REPLY,
156/// BR_DEAD_REPLY,
157/// BR_TRANSACTION_COMPLETE,
158/// BR_INCREFS,
159/// BR_ACQUIRE,
160/// BR_RELEASE,
161/// BR_DECREFS,
162/// BR_NOOP,
163/// BR_SPAWN_LOOPER,
164/// BR_DEAD_BINDER,
165/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
166/// BR_FAILED_REPLY
167/// );
168///
169/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
170/// ```
171#[proc_macro]
172pub fn concat_idents(ts: TokenStream) -> TokenStream {
173 concat_idents::concat_idents(ts)
174}
175
176/// Used to specify the pinning information of the fields of a struct.
177///
178/// This is somewhat similar in purpose as
179/// [pin-project-lite](https://crates.io/crates/pin-project-lite).
180/// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each
181/// field you want to structurally pin.
182///
183/// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`,
184/// then `#[pin]` directs the type of initializer that is required.
185///
186/// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this
187/// macro, and change your `Drop` implementation to `PinnedDrop` annotated with
188/// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care.
189///
190/// # Examples
191///
192/// ```rust,ignore
193/// #[pin_data]
194/// struct DriverData {
195/// #[pin]
196/// queue: Mutex<Vec<Command>>,
197/// buf: Box<[u8; 1024 * 1024]>,
198/// }
199/// ```
200///
201/// ```rust,ignore
202/// #[pin_data(PinnedDrop)]
203/// struct DriverData {
204/// #[pin]
205/// queue: Mutex<Vec<Command>>,
206/// buf: Box<[u8; 1024 * 1024]>,
207/// raw_info: *mut Info,
208/// }
209///
210/// #[pinned_drop]
211/// impl PinnedDrop for DriverData {
212/// fn drop(self: Pin<&mut Self>) {
213/// unsafe { bindings::destroy_info(self.raw_info) };
214/// }
215/// }
216/// ```
217///
218/// [`pin_init!`]: ../kernel/macro.pin_init.html
219// ^ cannot use direct link, since `kernel` is not a dependency of `macros`.
220#[proc_macro_attribute]
221pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream {
222 pin_data::pin_data(inner, item)
223}
224
225/// Used to implement `PinnedDrop` safely.
226///
227/// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`.
228///
229/// # Examples
230///
231/// ```rust,ignore
232/// #[pin_data(PinnedDrop)]
233/// struct DriverData {
234/// #[pin]
235/// queue: Mutex<Vec<Command>>,
236/// buf: Box<[u8; 1024 * 1024]>,
237/// raw_info: *mut Info,
238/// }
239///
240/// #[pinned_drop]
241/// impl PinnedDrop for DriverData {
242/// fn drop(self: Pin<&mut Self>) {
243/// unsafe { bindings::destroy_info(self.raw_info) };
244/// }
245/// }
246/// ```
247#[proc_macro_attribute]
248pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
249 pinned_drop::pinned_drop(args, input)
250}
251
252/// Paste identifiers together.
253///
254/// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a
255/// single identifier.
256///
257/// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers
258/// (literals, lifetimes and documentation strings are not supported). There is a difference in
259/// supported modifiers as well.
260///
261/// # Example
262///
263/// ```ignore
264/// use kernel::macro::paste;
265///
266/// macro_rules! pub_no_prefix {
267/// ($prefix:ident, $($newname:ident),+) => {
268/// paste! {
269/// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+
270/// }
271/// };
272/// }
273///
274/// pub_no_prefix!(
275/// binder_driver_return_protocol_,
276/// BR_OK,
277/// BR_ERROR,
278/// BR_TRANSACTION,
279/// BR_REPLY,
280/// BR_DEAD_REPLY,
281/// BR_TRANSACTION_COMPLETE,
282/// BR_INCREFS,
283/// BR_ACQUIRE,
284/// BR_RELEASE,
285/// BR_DECREFS,
286/// BR_NOOP,
287/// BR_SPAWN_LOOPER,
288/// BR_DEAD_BINDER,
289/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
290/// BR_FAILED_REPLY
291/// );
292///
293/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
294/// ```
295///
296/// # Modifiers
297///
298/// For each identifier, it is possible to attach one or multiple modifiers to
299/// it.
300///
301/// Currently supported modifiers are:
302/// * `span`: change the span of concatenated identifier to the span of the specified token. By
303/// default the span of the `[< >]` group is used.
304/// * `lower`: change the identifier to lower case.
305/// * `upper`: change the identifier to upper case.
306///
307/// ```ignore
308/// use kernel::macro::paste;
309///
310/// macro_rules! pub_no_prefix {
311/// ($prefix:ident, $($newname:ident),+) => {
312/// kernel::macros::paste! {
313/// $(pub(crate) const fn [<$newname:lower:span>]: u32 = [<$prefix $newname:span>];)+
314/// }
315/// };
316/// }
317///
318/// pub_no_prefix!(
319/// binder_driver_return_protocol_,
320/// BR_OK,
321/// BR_ERROR,
322/// BR_TRANSACTION,
323/// BR_REPLY,
324/// BR_DEAD_REPLY,
325/// BR_TRANSACTION_COMPLETE,
326/// BR_INCREFS,
327/// BR_ACQUIRE,
328/// BR_RELEASE,
329/// BR_DECREFS,
330/// BR_NOOP,
331/// BR_SPAWN_LOOPER,
332/// BR_DEAD_BINDER,
333/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
334/// BR_FAILED_REPLY
335/// );
336///
337/// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK);
338/// ```
339///
340/// [`paste`]: https://docs.rs/paste/
341#[proc_macro]
342pub fn paste(input: TokenStream) -> TokenStream {
343 let mut tokens = input.into_iter().collect();
344 paste::expand(&mut tokens);
345 tokens.into_iter().collect()
346}
347
348/// Derives the [`Zeroable`] trait for the given struct.
349///
350/// This can only be used for structs where every field implements the [`Zeroable`] trait.
351///
352/// # Examples
353///
354/// ```rust,ignore
355/// #[derive(Zeroable)]
356/// pub struct DriverData {
357/// id: i64,
358/// buf_ptr: *mut u8,
359/// len: usize,
360/// }
361/// ```
362#[proc_macro_derive(Zeroable)]
363pub fn derive_zeroable(input: TokenStream) -> TokenStream {
364 zeroable::derive(input)
365}