408 lines
12 KiB
Rust
408 lines
12 KiB
Rust
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// SPDX-License-Identifier: GPL-2.0
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//! Crate for all kernel procedural macros.
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#[macro_use]
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mod quote;
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mod concat_idents;
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mod helpers;
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mod module;
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mod paste;
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mod pin_data;
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mod pinned_drop;
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mod vtable;
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mod zeroable;
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use proc_macro::TokenStream;
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/// Declares a kernel module.
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///
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/// The `type` argument should be a type which implements the [`Module`]
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/// trait. Also accepts various forms of kernel metadata.
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///
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/// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h)
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///
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/// [`Module`]: ../kernel/trait.Module.html
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///
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/// # Examples
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///
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/// ```ignore
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/// use kernel::prelude::*;
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///
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/// module!{
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/// type: MyModule,
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/// name: "my_kernel_module",
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/// author: "Rust for Linux Contributors",
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/// description: "My very own kernel module!",
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/// license: "GPL",
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/// params: {
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/// my_i32: i32 {
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/// default: 42,
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/// permissions: 0o000,
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/// description: "Example of i32",
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/// },
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/// writeable_i32: i32 {
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/// default: 42,
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/// permissions: 0o644,
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/// description: "Example of i32",
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/// },
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/// },
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/// }
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///
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/// struct MyModule;
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///
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/// impl kernel::Module for MyModule {
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/// fn init() -> Result<Self> {
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/// // If the parameter is writeable, then the kparam lock must be
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/// // taken to read the parameter:
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/// {
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/// let lock = THIS_MODULE.kernel_param_lock();
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/// pr_info!("i32 param is: {}\n", writeable_i32.read(&lock));
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/// }
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/// // If the parameter is read only, it can be read without locking
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/// // the kernel parameters:
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/// pr_info!("i32 param is: {}\n", my_i32.read());
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/// Ok(Self)
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/// }
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/// }
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/// ```
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///
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/// # Supported argument types
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/// - `type`: type which implements the [`Module`] trait (required).
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/// - `name`: byte array of the name of the kernel module (required).
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/// - `author`: byte array of the author of the kernel module.
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/// - `description`: byte array of the description of the kernel module.
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/// - `license`: byte array of the license of the kernel module (required).
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/// - `alias`: byte array of alias name of the kernel module.
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#[proc_macro]
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pub fn module(ts: TokenStream) -> TokenStream {
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module::module(ts)
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}
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/// Declares or implements a vtable trait.
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///
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/// Linux's use of pure vtables is very close to Rust traits, but they differ
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/// in how unimplemented functions are represented. In Rust, traits can provide
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/// default implementation for all non-required methods (and the default
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/// implementation could just return `Error::EINVAL`); Linux typically use C
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/// `NULL` pointers to represent these functions.
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///
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/// This attribute closes that gap. A trait can be annotated with the
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/// `#[vtable]` attribute. Implementers of the trait will then also have to
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/// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*`
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/// associated constant bool for each method in the trait that is set to true if
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/// the implementer has overridden the associated method.
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///
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/// For a trait method to be optional, it must have a default implementation.
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/// This is also the case for traits annotated with `#[vtable]`, but in this
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/// case the default implementation will never be executed. The reason for this
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/// is that the functions will be called through function pointers installed in
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/// C side vtables. When an optional method is not implemented on a `#[vtable]`
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/// trait, a NULL entry is installed in the vtable. Thus the default
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/// implementation is never called. Since these traits are not designed to be
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/// used on the Rust side, it should not be possible to call the default
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/// implementation. This is done to ensure that we call the vtable methods
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/// through the C vtable, and not through the Rust vtable. Therefore, the
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/// default implementation should call `kernel::build_error`, which prevents
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/// calls to this function at compile time:
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///
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/// ```compile_fail
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/// # use kernel::error::VTABLE_DEFAULT_ERROR;
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/// kernel::build_error(VTABLE_DEFAULT_ERROR)
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/// ```
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///
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/// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`].
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///
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/// This macro should not be used when all functions are required.
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///
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/// # Examples
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///
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/// ```ignore
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/// use kernel::error::VTABLE_DEFAULT_ERROR;
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/// use kernel::prelude::*;
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///
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/// // Declares a `#[vtable]` trait
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/// #[vtable]
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/// pub trait Operations: Send + Sync + Sized {
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/// fn foo(&self) -> Result<()> {
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/// kernel::build_error(VTABLE_DEFAULT_ERROR)
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/// }
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///
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/// fn bar(&self) -> Result<()> {
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/// kernel::build_error(VTABLE_DEFAULT_ERROR)
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/// }
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/// }
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///
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/// struct Foo;
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///
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/// // Implements the `#[vtable]` trait
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/// #[vtable]
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/// impl Operations for Foo {
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/// fn foo(&self) -> Result<()> {
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/// # Err(EINVAL)
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/// // ...
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/// }
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/// }
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///
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/// assert_eq!(<Foo as Operations>::HAS_FOO, true);
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/// assert_eq!(<Foo as Operations>::HAS_BAR, false);
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/// ```
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///
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/// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html
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#[proc_macro_attribute]
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pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
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vtable::vtable(attr, ts)
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}
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/// Concatenate two identifiers.
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///
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/// This is useful in macros that need to declare or reference items with names
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/// starting with a fixed prefix and ending in a user specified name. The resulting
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/// identifier has the span of the second argument.
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///
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/// # Examples
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///
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/// ```ignore
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/// use kernel::macro::concat_idents;
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///
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/// macro_rules! pub_no_prefix {
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/// ($prefix:ident, $($newname:ident),+) => {
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/// $(pub(crate) const $newname: u32 = kernel::macros::concat_idents!($prefix, $newname);)+
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/// };
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/// }
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///
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/// pub_no_prefix!(
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/// binder_driver_return_protocol_,
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/// BR_OK,
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/// BR_ERROR,
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/// BR_TRANSACTION,
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/// BR_REPLY,
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/// BR_DEAD_REPLY,
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/// BR_TRANSACTION_COMPLETE,
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/// BR_INCREFS,
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/// BR_ACQUIRE,
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/// BR_RELEASE,
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/// BR_DECREFS,
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/// BR_NOOP,
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/// BR_SPAWN_LOOPER,
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/// BR_DEAD_BINDER,
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/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
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/// BR_FAILED_REPLY
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/// );
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///
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/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
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/// ```
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#[proc_macro]
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pub fn concat_idents(ts: TokenStream) -> TokenStream {
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concat_idents::concat_idents(ts)
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}
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/// Used to specify the pinning information of the fields of a struct.
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///
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/// This is somewhat similar in purpose as
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/// [pin-project-lite](https://crates.io/crates/pin-project-lite).
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/// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each
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/// field you want to structurally pin.
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///
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/// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`,
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/// then `#[pin]` directs the type of initializer that is required.
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///
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/// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this
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/// macro, and change your `Drop` implementation to `PinnedDrop` annotated with
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/// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care.
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///
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/// # Examples
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///
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/// ```rust,ignore
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/// #[pin_data]
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/// struct DriverData {
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/// #[pin]
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/// queue: Mutex<Vec<Command>>,
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/// buf: Box<[u8; 1024 * 1024]>,
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/// }
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/// ```
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///
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/// ```rust,ignore
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/// #[pin_data(PinnedDrop)]
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/// struct DriverData {
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/// #[pin]
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/// queue: Mutex<Vec<Command>>,
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/// buf: Box<[u8; 1024 * 1024]>,
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/// raw_info: *mut Info,
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/// }
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///
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/// #[pinned_drop]
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/// impl PinnedDrop for DriverData {
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/// fn drop(self: Pin<&mut Self>) {
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/// unsafe { bindings::destroy_info(self.raw_info) };
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/// }
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/// }
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/// ```
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///
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/// [`pin_init!`]: ../kernel/macro.pin_init.html
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// ^ cannot use direct link, since `kernel` is not a dependency of `macros`.
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#[proc_macro_attribute]
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pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream {
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pin_data::pin_data(inner, item)
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}
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/// Used to implement `PinnedDrop` safely.
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///
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/// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`.
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///
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/// # Examples
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///
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/// ```rust,ignore
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/// #[pin_data(PinnedDrop)]
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/// struct DriverData {
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/// #[pin]
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/// queue: Mutex<Vec<Command>>,
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/// buf: Box<[u8; 1024 * 1024]>,
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/// raw_info: *mut Info,
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/// }
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///
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/// #[pinned_drop]
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/// impl PinnedDrop for DriverData {
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/// fn drop(self: Pin<&mut Self>) {
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/// unsafe { bindings::destroy_info(self.raw_info) };
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/// }
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/// }
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/// ```
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#[proc_macro_attribute]
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pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
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pinned_drop::pinned_drop(args, input)
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}
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/// Paste identifiers together.
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///
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/// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a
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/// single identifier.
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///
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/// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and
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/// literals (lifetimes and documentation strings are not supported). There is a difference in
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/// supported modifiers as well.
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///
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/// # Example
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///
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/// ```ignore
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/// use kernel::macro::paste;
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///
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/// macro_rules! pub_no_prefix {
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/// ($prefix:ident, $($newname:ident),+) => {
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/// paste! {
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/// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+
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/// }
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/// };
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/// }
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///
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/// pub_no_prefix!(
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/// binder_driver_return_protocol_,
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/// BR_OK,
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/// BR_ERROR,
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/// BR_TRANSACTION,
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/// BR_REPLY,
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/// BR_DEAD_REPLY,
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/// BR_TRANSACTION_COMPLETE,
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/// BR_INCREFS,
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/// BR_ACQUIRE,
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/// BR_RELEASE,
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/// BR_DECREFS,
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/// BR_NOOP,
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/// BR_SPAWN_LOOPER,
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/// BR_DEAD_BINDER,
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/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
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/// BR_FAILED_REPLY
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/// );
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///
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/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
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/// ```
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///
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/// # Modifiers
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///
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/// For each identifier, it is possible to attach one or multiple modifiers to
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/// it.
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///
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/// Currently supported modifiers are:
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/// * `span`: change the span of concatenated identifier to the span of the specified token. By
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/// default the span of the `[< >]` group is used.
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/// * `lower`: change the identifier to lower case.
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/// * `upper`: change the identifier to upper case.
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///
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/// ```ignore
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/// use kernel::macro::paste;
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///
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/// macro_rules! pub_no_prefix {
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/// ($prefix:ident, $($newname:ident),+) => {
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/// kernel::macros::paste! {
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/// $(pub(crate) const fn [<$newname:lower:span>]: u32 = [<$prefix $newname:span>];)+
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/// }
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/// };
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/// }
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///
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/// pub_no_prefix!(
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/// binder_driver_return_protocol_,
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/// BR_OK,
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/// BR_ERROR,
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/// BR_TRANSACTION,
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/// BR_REPLY,
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/// BR_DEAD_REPLY,
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/// BR_TRANSACTION_COMPLETE,
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/// BR_INCREFS,
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/// BR_ACQUIRE,
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/// BR_RELEASE,
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/// BR_DECREFS,
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/// BR_NOOP,
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/// BR_SPAWN_LOOPER,
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/// BR_DEAD_BINDER,
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/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
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/// BR_FAILED_REPLY
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/// );
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///
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/// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK);
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/// ```
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///
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/// # Literals
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///
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/// Literals can also be concatenated with other identifiers:
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///
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/// ```ignore
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/// macro_rules! create_numbered_fn {
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/// ($name:literal, $val:literal) => {
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||
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|
/// kernel::macros::paste! {
|
||
|
|
/// fn [<some_ $name _fn $val>]() -> u32 { $val }
|
||
|
|
/// }
|
||
|
|
/// };
|
||
|
|
/// }
|
||
|
|
///
|
||
|
|
/// create_numbered_fn!("foo", 100);
|
||
|
|
///
|
||
|
|
/// assert_eq!(some_foo_fn100(), 100)
|
||
|
|
/// ```
|
||
|
|
///
|
||
|
|
/// [`paste`]: https://docs.rs/paste/
|
||
|
|
#[proc_macro]
|
||
|
|
pub fn paste(input: TokenStream) -> TokenStream {
|
||
|
|
let mut tokens = input.into_iter().collect();
|
||
|
|
paste::expand(&mut tokens);
|
||
|
|
tokens.into_iter().collect()
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Derives the [`Zeroable`] trait for the given struct.
|
||
|
|
///
|
||
|
|
/// This can only be used for structs where every field implements the [`Zeroable`] trait.
|
||
|
|
///
|
||
|
|
/// # Examples
|
||
|
|
///
|
||
|
|
/// ```rust,ignore
|
||
|
|
/// #[derive(Zeroable)]
|
||
|
|
/// pub struct DriverData {
|
||
|
|
/// id: i64,
|
||
|
|
/// buf_ptr: *mut u8,
|
||
|
|
/// len: usize,
|
||
|
|
/// }
|
||
|
|
/// ```
|
||
|
|
#[proc_macro_derive(Zeroable)]
|
||
|
|
pub fn derive_zeroable(input: TokenStream) -> TokenStream {
|
||
|
|
zeroable::derive(input)
|
||
|
|
}
|