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 pin_data;
11mod pinned_drop;
12mod vtable;
13
14use proc_macro::TokenStream;
15
16/// Declares a kernel module.
17///
18/// The `type` argument should be a type which implements the [`Module`]
19/// trait. Also accepts various forms of kernel metadata.
20///
21/// C header: [`include/linux/moduleparam.h`](../../../include/linux/moduleparam.h)
22///
23/// [`Module`]: ../kernel/trait.Module.html
24///
25/// # Examples
26///
27/// ```ignore
28/// use kernel::prelude::*;
29///
30/// module!{
31/// type: MyModule,
32/// name: "my_kernel_module",
33/// author: "Rust for Linux Contributors",
34/// description: "My very own kernel module!",
35/// license: "GPL",
36/// params: {
37/// my_i32: i32 {
38/// default: 42,
39/// permissions: 0o000,
40/// description: "Example of i32",
41/// },
42/// writeable_i32: i32 {
43/// default: 42,
44/// permissions: 0o644,
45/// description: "Example of i32",
46/// },
47/// },
48/// }
49///
50/// struct MyModule;
51///
52/// impl kernel::Module for MyModule {
53/// fn init() -> Result<Self> {
54/// // If the parameter is writeable, then the kparam lock must be
55/// // taken to read the parameter:
56/// {
57/// let lock = THIS_MODULE.kernel_param_lock();
58/// pr_info!("i32 param is: {}\n", writeable_i32.read(&lock));
59/// }
60/// // If the parameter is read only, it can be read without locking
61/// // the kernel parameters:
62/// pr_info!("i32 param is: {}\n", my_i32.read());
63/// Ok(Self)
64/// }
65/// }
66/// ```
67///
68/// # Supported argument types
69/// - `type`: type which implements the [`Module`] trait (required).
70/// - `name`: byte array of the name of the kernel module (required).
71/// - `author`: byte array of the author of the kernel module.
72/// - `description`: byte array of the description of the kernel module.
73/// - `license`: byte array of the license of the kernel module (required).
74/// - `alias`: byte array of alias name of the kernel module.
75#[proc_macro]
76pub fn module(ts: TokenStream) -> TokenStream {
77 module::module(ts)
78}
79
80/// Declares or implements a vtable trait.
81///
82/// Linux's use of pure vtables is very close to Rust traits, but they differ
83/// in how unimplemented functions are represented. In Rust, traits can provide
84/// default implementation for all non-required methods (and the default
85/// implementation could just return `Error::EINVAL`); Linux typically use C
86/// `NULL` pointers to represent these functions.
87///
88/// This attribute is intended to close the gap. Traits can be declared and
89/// implemented with the `#[vtable]` attribute, and a `HAS_*` associated constant
90/// will be generated for each method in the trait, indicating if the implementor
91/// has overridden a method.
92///
93/// This attribute is not needed if all methods are required.
94///
95/// # Examples
96///
97/// ```ignore
98/// use kernel::prelude::*;
99///
100/// // Declares a `#[vtable]` trait
101/// #[vtable]
102/// pub trait Operations: Send + Sync + Sized {
103/// fn foo(&self) -> Result<()> {
104/// Err(EINVAL)
105/// }
106///
107/// fn bar(&self) -> Result<()> {
108/// Err(EINVAL)
109/// }
110/// }
111///
112/// struct Foo;
113///
114/// // Implements the `#[vtable]` trait
115/// #[vtable]
116/// impl Operations for Foo {
117/// fn foo(&self) -> Result<()> {
118/// # Err(EINVAL)
119/// // ...
120/// }
121/// }
122///
123/// assert_eq!(<Foo as Operations>::HAS_FOO, true);
124/// assert_eq!(<Foo as Operations>::HAS_BAR, false);
125/// ```
126#[proc_macro_attribute]
127pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
128 vtable::vtable(attr, ts)
129}
130
131/// Concatenate two identifiers.
132///
133/// This is useful in macros that need to declare or reference items with names
134/// starting with a fixed prefix and ending in a user specified name. The resulting
135/// identifier has the span of the second argument.
136///
137/// # Examples
138///
139/// ```ignore
140/// use kernel::macro::concat_idents;
141///
142/// macro_rules! pub_no_prefix {
143/// ($prefix:ident, $($newname:ident),+) => {
144/// $(pub(crate) const $newname: u32 = kernel::macros::concat_idents!($prefix, $newname);)+
145/// };
146/// }
147///
148/// pub_no_prefix!(
149/// binder_driver_return_protocol_,
150/// BR_OK,
151/// BR_ERROR,
152/// BR_TRANSACTION,
153/// BR_REPLY,
154/// BR_DEAD_REPLY,
155/// BR_TRANSACTION_COMPLETE,
156/// BR_INCREFS,
157/// BR_ACQUIRE,
158/// BR_RELEASE,
159/// BR_DECREFS,
160/// BR_NOOP,
161/// BR_SPAWN_LOOPER,
162/// BR_DEAD_BINDER,
163/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
164/// BR_FAILED_REPLY
165/// );
166///
167/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
168/// ```
169#[proc_macro]
170pub fn concat_idents(ts: TokenStream) -> TokenStream {
171 concat_idents::concat_idents(ts)
172}
173
174/// Used to specify the pinning information of the fields of a struct.
175///
176/// This is somewhat similar in purpose as
177/// [pin-project-lite](https://crates.io/crates/pin-project-lite).
178/// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each
179/// field you want to structurally pin.
180///
181/// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`,
182/// then `#[pin]` directs the type of initializer that is required.
183///
184/// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this
185/// macro, and change your `Drop` implementation to `PinnedDrop` annotated with
186/// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care.
187///
188/// # Examples
189///
190/// ```rust,ignore
191/// #[pin_data]
192/// struct DriverData {
193/// #[pin]
194/// queue: Mutex<Vec<Command>>,
195/// buf: Box<[u8; 1024 * 1024]>,
196/// }
197/// ```
198///
199/// ```rust,ignore
200/// #[pin_data(PinnedDrop)]
201/// struct DriverData {
202/// #[pin]
203/// queue: Mutex<Vec<Command>>,
204/// buf: Box<[u8; 1024 * 1024]>,
205/// raw_info: *mut Info,
206/// }
207///
208/// #[pinned_drop]
209/// impl PinnedDrop for DriverData {
210/// fn drop(self: Pin<&mut Self>) {
211/// unsafe { bindings::destroy_info(self.raw_info) };
212/// }
213/// }
214/// ```
215///
216/// [`pin_init!`]: ../kernel/macro.pin_init.html
217// ^ cannot use direct link, since `kernel` is not a dependency of `macros`.
218#[proc_macro_attribute]
219pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream {
220 pin_data::pin_data(inner, item)
221}
222
223/// Used to implement `PinnedDrop` safely.
224///
225/// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`.
226///
227/// # Examples
228///
229/// ```rust,ignore
230/// #[pin_data(PinnedDrop)]
231/// struct DriverData {
232/// #[pin]
233/// queue: Mutex<Vec<Command>>,
234/// buf: Box<[u8; 1024 * 1024]>,
235/// raw_info: *mut Info,
236/// }
237///
238/// #[pinned_drop]
239/// impl PinnedDrop for DriverData {
240/// fn drop(self: Pin<&mut Self>) {
241/// unsafe { bindings::destroy_info(self.raw_info) };
242/// }
243/// }
244/// ```
245#[proc_macro_attribute]
246pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
247 pinned_drop::pinned_drop(args, input)
248}