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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#[macro_use]
10mod quote;
11mod concat_idents;
12mod helpers;
13mod module;
14mod paste;
15mod pin_data;
16mod pinned_drop;
17mod vtable;
18mod zeroable;
19
20use proc_macro::TokenStream;
21
22/// Declares a kernel module.
23///
24/// The `type` argument should be a type which implements the [`Module`]
25/// trait. Also accepts various forms of kernel metadata.
26///
27/// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h)
28///
29/// [`Module`]: ../kernel/trait.Module.html
30///
31/// # Examples
32///
33/// ```
34/// use kernel::prelude::*;
35///
36/// module!{
37/// type: MyModule,
38/// name: "my_kernel_module",
39/// author: "Rust for Linux Contributors",
40/// description: "My very own kernel module!",
41/// license: "GPL",
42/// alias: ["alternate_module_name"],
43/// }
44///
45/// struct MyModule(i32);
46///
47/// impl kernel::Module for MyModule {
48/// fn init(_module: &'static ThisModule) -> Result<Self> {
49/// let foo: i32 = 42;
50/// pr_info!("I contain: {}\n", foo);
51/// Ok(Self(foo))
52/// }
53/// }
54/// # fn main() {}
55/// ```
56///
57/// ## Firmware
58///
59/// The following example shows how to declare a kernel module that needs
60/// to load binary firmware files. You need to specify the file names of
61/// the firmware in the `firmware` field. The information is embedded
62/// in the `modinfo` section of the kernel module. For example, a tool to
63/// build an initramfs uses this information to put the firmware files into
64/// the initramfs image.
65///
66/// ```
67/// use kernel::prelude::*;
68///
69/// module!{
70/// type: MyDeviceDriverModule,
71/// name: "my_device_driver_module",
72/// author: "Rust for Linux Contributors",
73/// description: "My device driver requires firmware",
74/// license: "GPL",
75/// firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"],
76/// }
77///
78/// struct MyDeviceDriverModule;
79///
80/// impl kernel::Module for MyDeviceDriverModule {
81/// fn init(_module: &'static ThisModule) -> Result<Self> {
82/// Ok(Self)
83/// }
84/// }
85/// # fn main() {}
86/// ```
87///
88/// # Supported argument types
89/// - `type`: type which implements the [`Module`] trait (required).
90/// - `name`: ASCII string literal of the name of the kernel module (required).
91/// - `author`: string literal of the author of the kernel module.
92/// - `description`: string literal of the description of the kernel module.
93/// - `license`: ASCII string literal of the license of the kernel module (required).
94/// - `alias`: array of ASCII string literals of the alias names of the kernel module.
95/// - `firmware`: array of ASCII string literals of the firmware files of
96/// the kernel module.
97#[proc_macro]
98pub fn module(ts: TokenStream) -> TokenStream {
99 module::module(ts)
100}
101
102/// Declares or implements a vtable trait.
103///
104/// Linux's use of pure vtables is very close to Rust traits, but they differ
105/// in how unimplemented functions are represented. In Rust, traits can provide
106/// default implementation for all non-required methods (and the default
107/// implementation could just return `Error::EINVAL`); Linux typically use C
108/// `NULL` pointers to represent these functions.
109///
110/// This attribute closes that gap. A trait can be annotated with the
111/// `#[vtable]` attribute. Implementers of the trait will then also have to
112/// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*`
113/// associated constant bool for each method in the trait that is set to true if
114/// the implementer has overridden the associated method.
115///
116/// For a trait method to be optional, it must have a default implementation.
117/// This is also the case for traits annotated with `#[vtable]`, but in this
118/// case the default implementation will never be executed. The reason for this
119/// is that the functions will be called through function pointers installed in
120/// C side vtables. When an optional method is not implemented on a `#[vtable]`
121/// trait, a NULL entry is installed in the vtable. Thus the default
122/// implementation is never called. Since these traits are not designed to be
123/// used on the Rust side, it should not be possible to call the default
124/// implementation. This is done to ensure that we call the vtable methods
125/// through the C vtable, and not through the Rust vtable. Therefore, the
126/// default implementation should call `kernel::build_error`, which prevents
127/// calls to this function at compile time:
128///
129/// ```compile_fail
130/// # // Intentionally missing `use`s to simplify `rusttest`.
131/// kernel::build_error(VTABLE_DEFAULT_ERROR)
132/// ```
133///
134/// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`].
135///
136/// This macro should not be used when all functions are required.
137///
138/// # Examples
139///
140/// ```
141/// use kernel::error::VTABLE_DEFAULT_ERROR;
142/// use kernel::prelude::*;
143///
144/// // Declares a `#[vtable]` trait
145/// #[vtable]
146/// pub trait Operations: Send + Sync + Sized {
147/// fn foo(&self) -> Result<()> {
148/// kernel::build_error(VTABLE_DEFAULT_ERROR)
149/// }
150///
151/// fn bar(&self) -> Result<()> {
152/// kernel::build_error(VTABLE_DEFAULT_ERROR)
153/// }
154/// }
155///
156/// struct Foo;
157///
158/// // Implements the `#[vtable]` trait
159/// #[vtable]
160/// impl Operations for Foo {
161/// fn foo(&self) -> Result<()> {
162/// # Err(EINVAL)
163/// // ...
164/// }
165/// }
166///
167/// assert_eq!(<Foo as Operations>::HAS_FOO, true);
168/// assert_eq!(<Foo as Operations>::HAS_BAR, false);
169/// ```
170///
171/// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html
172#[proc_macro_attribute]
173pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
174 vtable::vtable(attr, ts)
175}
176
177/// Concatenate two identifiers.
178///
179/// This is useful in macros that need to declare or reference items with names
180/// starting with a fixed prefix and ending in a user specified name. The resulting
181/// identifier has the span of the second argument.
182///
183/// # Examples
184///
185/// ```
186/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
187/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
188/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
189/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
190/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
191/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
192/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
193/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
194/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
195/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
196/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
197/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
198/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
199/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
200/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
201/// use kernel::macros::concat_idents;
202///
203/// macro_rules! pub_no_prefix {
204/// ($prefix:ident, $($newname:ident),+) => {
205/// $(pub(crate) const $newname: u32 = concat_idents!($prefix, $newname);)+
206/// };
207/// }
208///
209/// pub_no_prefix!(
210/// binder_driver_return_protocol_,
211/// BR_OK,
212/// BR_ERROR,
213/// BR_TRANSACTION,
214/// BR_REPLY,
215/// BR_DEAD_REPLY,
216/// BR_TRANSACTION_COMPLETE,
217/// BR_INCREFS,
218/// BR_ACQUIRE,
219/// BR_RELEASE,
220/// BR_DECREFS,
221/// BR_NOOP,
222/// BR_SPAWN_LOOPER,
223/// BR_DEAD_BINDER,
224/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
225/// BR_FAILED_REPLY
226/// );
227///
228/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
229/// ```
230#[proc_macro]
231pub fn concat_idents(ts: TokenStream) -> TokenStream {
232 concat_idents::concat_idents(ts)
233}
234
235/// Used to specify the pinning information of the fields of a struct.
236///
237/// This is somewhat similar in purpose as
238/// [pin-project-lite](https://crates.io/crates/pin-project-lite).
239/// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each
240/// field you want to structurally pin.
241///
242/// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`,
243/// then `#[pin]` directs the type of initializer that is required.
244///
245/// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this
246/// macro, and change your `Drop` implementation to `PinnedDrop` annotated with
247/// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care.
248///
249/// # Examples
250///
251/// ```
252/// # #![feature(lint_reasons)]
253/// # use kernel::prelude::*;
254/// # use std::{sync::Mutex, process::Command};
255/// # use kernel::macros::pin_data;
256/// #[pin_data]
257/// struct DriverData {
258/// #[pin]
259/// queue: Mutex<KVec<Command>>,
260/// buf: KBox<[u8; 1024 * 1024]>,
261/// }
262/// ```
263///
264/// ```
265/// # #![feature(lint_reasons)]
266/// # use kernel::prelude::*;
267/// # use std::{sync::Mutex, process::Command};
268/// # use core::pin::Pin;
269/// # pub struct Info;
270/// # mod bindings {
271/// # pub unsafe fn destroy_info(_ptr: *mut super::Info) {}
272/// # }
273/// use kernel::macros::{pin_data, pinned_drop};
274///
275/// #[pin_data(PinnedDrop)]
276/// struct DriverData {
277/// #[pin]
278/// queue: Mutex<KVec<Command>>,
279/// buf: KBox<[u8; 1024 * 1024]>,
280/// raw_info: *mut Info,
281/// }
282///
283/// #[pinned_drop]
284/// impl PinnedDrop for DriverData {
285/// fn drop(self: Pin<&mut Self>) {
286/// unsafe { bindings::destroy_info(self.raw_info) };
287/// }
288/// }
289/// # fn main() {}
290/// ```
291///
292/// [`pin_init!`]: ../kernel/macro.pin_init.html
293// ^ cannot use direct link, since `kernel` is not a dependency of `macros`.
294#[proc_macro_attribute]
295pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream {
296 pin_data::pin_data(inner, item)
297}
298
299/// Used to implement `PinnedDrop` safely.
300///
301/// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`.
302///
303/// # Examples
304///
305/// ```
306/// # #![feature(lint_reasons)]
307/// # use kernel::prelude::*;
308/// # use macros::{pin_data, pinned_drop};
309/// # use std::{sync::Mutex, process::Command};
310/// # use core::pin::Pin;
311/// # mod bindings {
312/// # pub struct Info;
313/// # pub unsafe fn destroy_info(_ptr: *mut Info) {}
314/// # }
315/// #[pin_data(PinnedDrop)]
316/// struct DriverData {
317/// #[pin]
318/// queue: Mutex<KVec<Command>>,
319/// buf: KBox<[u8; 1024 * 1024]>,
320/// raw_info: *mut bindings::Info,
321/// }
322///
323/// #[pinned_drop]
324/// impl PinnedDrop for DriverData {
325/// fn drop(self: Pin<&mut Self>) {
326/// unsafe { bindings::destroy_info(self.raw_info) };
327/// }
328/// }
329/// ```
330#[proc_macro_attribute]
331pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
332 pinned_drop::pinned_drop(args, input)
333}
334
335/// Paste identifiers together.
336///
337/// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a
338/// single identifier.
339///
340/// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and
341/// literals (lifetimes and documentation strings are not supported). There is a difference in
342/// supported modifiers as well.
343///
344/// # Example
345///
346/// ```
347/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
348/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
349/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
350/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
351/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
352/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
353/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
354/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
355/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
356/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
357/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
358/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
359/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
360/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
361/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
362/// macro_rules! pub_no_prefix {
363/// ($prefix:ident, $($newname:ident),+) => {
364/// kernel::macros::paste! {
365/// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+
366/// }
367/// };
368/// }
369///
370/// pub_no_prefix!(
371/// binder_driver_return_protocol_,
372/// BR_OK,
373/// BR_ERROR,
374/// BR_TRANSACTION,
375/// BR_REPLY,
376/// BR_DEAD_REPLY,
377/// BR_TRANSACTION_COMPLETE,
378/// BR_INCREFS,
379/// BR_ACQUIRE,
380/// BR_RELEASE,
381/// BR_DECREFS,
382/// BR_NOOP,
383/// BR_SPAWN_LOOPER,
384/// BR_DEAD_BINDER,
385/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
386/// BR_FAILED_REPLY
387/// );
388///
389/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
390/// ```
391///
392/// # Modifiers
393///
394/// For each identifier, it is possible to attach one or multiple modifiers to
395/// it.
396///
397/// Currently supported modifiers are:
398/// * `span`: change the span of concatenated identifier to the span of the specified token. By
399/// default the span of the `[< >]` group is used.
400/// * `lower`: change the identifier to lower case.
401/// * `upper`: change the identifier to upper case.
402///
403/// ```
404/// # const binder_driver_return_protocol_BR_OK: u32 = 0;
405/// # const binder_driver_return_protocol_BR_ERROR: u32 = 1;
406/// # const binder_driver_return_protocol_BR_TRANSACTION: u32 = 2;
407/// # const binder_driver_return_protocol_BR_REPLY: u32 = 3;
408/// # const binder_driver_return_protocol_BR_DEAD_REPLY: u32 = 4;
409/// # const binder_driver_return_protocol_BR_TRANSACTION_COMPLETE: u32 = 5;
410/// # const binder_driver_return_protocol_BR_INCREFS: u32 = 6;
411/// # const binder_driver_return_protocol_BR_ACQUIRE: u32 = 7;
412/// # const binder_driver_return_protocol_BR_RELEASE: u32 = 8;
413/// # const binder_driver_return_protocol_BR_DECREFS: u32 = 9;
414/// # const binder_driver_return_protocol_BR_NOOP: u32 = 10;
415/// # const binder_driver_return_protocol_BR_SPAWN_LOOPER: u32 = 11;
416/// # const binder_driver_return_protocol_BR_DEAD_BINDER: u32 = 12;
417/// # const binder_driver_return_protocol_BR_CLEAR_DEATH_NOTIFICATION_DONE: u32 = 13;
418/// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
419/// macro_rules! pub_no_prefix {
420/// ($prefix:ident, $($newname:ident),+) => {
421/// kernel::macros::paste! {
422/// $(pub(crate) const fn [<$newname:lower:span>]() -> u32 { [<$prefix $newname:span>] })+
423/// }
424/// };
425/// }
426///
427/// pub_no_prefix!(
428/// binder_driver_return_protocol_,
429/// BR_OK,
430/// BR_ERROR,
431/// BR_TRANSACTION,
432/// BR_REPLY,
433/// BR_DEAD_REPLY,
434/// BR_TRANSACTION_COMPLETE,
435/// BR_INCREFS,
436/// BR_ACQUIRE,
437/// BR_RELEASE,
438/// BR_DECREFS,
439/// BR_NOOP,
440/// BR_SPAWN_LOOPER,
441/// BR_DEAD_BINDER,
442/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
443/// BR_FAILED_REPLY
444/// );
445///
446/// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK);
447/// ```
448///
449/// # Literals
450///
451/// Literals can also be concatenated with other identifiers:
452///
453/// ```
454/// macro_rules! create_numbered_fn {
455/// ($name:literal, $val:literal) => {
456/// kernel::macros::paste! {
457/// fn [<some_ $name _fn $val>]() -> u32 { $val }
458/// }
459/// };
460/// }
461///
462/// create_numbered_fn!("foo", 100);
463///
464/// assert_eq!(some_foo_fn100(), 100)
465/// ```
466///
467/// [`paste`]: https://docs.rs/paste/
468#[proc_macro]
469pub fn paste(input: TokenStream) -> TokenStream {
470 let mut tokens = input.into_iter().collect();
471 paste::expand(&mut tokens);
472 tokens.into_iter().collect()
473}
474
475/// Derives the [`Zeroable`] trait for the given struct.
476///
477/// This can only be used for structs where every field implements the [`Zeroable`] trait.
478///
479/// # Examples
480///
481/// ```
482/// use kernel::macros::Zeroable;
483///
484/// #[derive(Zeroable)]
485/// pub struct DriverData {
486/// id: i64,
487/// buf_ptr: *mut u8,
488/// len: usize,
489/// }
490/// ```
491#[proc_macro_derive(Zeroable)]
492pub fn derive_zeroable(input: TokenStream) -> TokenStream {
493 zeroable::derive(input)
494}