Hi all, On Tue, 18 Mar 2025 10:35:04 +1100 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote: > > Thanks, I will see what I can come up with. (there are 2 resolutions below) When I merge the rust tree into linux-next, the complete resolution now looks like this: (the hunk in rust/kernel/sync.rs is needed due to a commit in the tip tree) 892715be4379deb333376e573113fd75672eca6c diff --cc drivers/gpu/drm/drm_panic_qr.rs index 5d21f6d10bcb,ecd87e8ffe05..f2a99681b998 --- a/drivers/gpu/drm/drm_panic_qr.rs +++ b/drivers/gpu/drm/drm_panic_qr.rs @@@ -27,7 -26,8 +27,7 @@@ //! * <https://github.com/erwanvivien/fast_qr> //! * <https://github.com/bjguillot/qr> - use kernel::str::CStr; -use core::cmp; + use kernel::{prelude::*, str::CStr}; #[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd)] struct Version(usize); diff --cc rust/Makefile index 089473a89d46,e761a8cc3bd5..3474f0b2b24c --- a/rust/Makefile +++ b/rust/Makefile @@@ -175,9 -199,9 +203,9 @@@ quiet_cmd_rustdoc_test_kernel = RUSTDO rm -rf $(objtree)/$(obj)/test/doctests/kernel; \ mkdir -p $(objtree)/$(obj)/test/doctests/kernel; \ OBJTREE=$(abspath $(objtree)) \ - $(RUSTDOC) --test $(rust_flags) \ + $(RUSTDOC) --test $(filter-out --remap-path-prefix=%,$(rust_flags)) \ - -L$(objtree)/$(obj) --extern ffi --extern kernel \ - --extern build_error --extern macros \ + -L$(objtree)/$(obj) --extern ffi --extern pin_init \ + --extern kernel --extern build_error --extern macros \ --extern bindings --extern uapi \ --no-run --crate-name kernel -Zunstable-options \ --sysroot=/dev/null \ diff --cc rust/kernel/alloc/kbox.rs index cb4ebea3b074,e6200cd1d06d..a4bde2616c4e --- a/rust/kernel/alloc/kbox.rs +++ b/rust/kernel/alloc/kbox.rs @@@ -99,6 -100,12 +100,10 @@@ pub type VBox<T> = Box<T, super::alloca /// ``` pub type KVBox<T> = Box<T, super::allocator::KVmalloc>; -// SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee). -// -// In this case we are allowed to use `T: ?Sized`, since all zeros is the `None` variant and there -// is no problem with a VTABLE pointer being null. -unsafe impl<T: ?Sized, A: Allocator> ZeroableOption for Box<T, A> {} ++// SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee: ++// https://doc.rust-lang.org/stable/std/option/index.html#representation). ++unsafe impl<T, A: Allocator> ZeroableOption for Box<T, A> {} + // SAFETY: `Box` is `Send` if `T` is `Send` because the `Box` owns a `T`. unsafe impl<T, A> Send for Box<T, A> where diff --cc rust/kernel/sync.rs index 4104bc26471a,3498fb344dc9..ee8ffd2955b8 --- a/rust/kernel/sync.rs +++ b/rust/kernel/sync.rs @@@ -5,8 -5,6 +5,8 @@@ //! This module contains the kernel APIs related to synchronisation that have been ported or //! wrapped for usage by Rust code in the kernel. - use crate::pin_init; ++use pin_init; +use crate::prelude::*; use crate::types::Opaque; mod arc; diff --cc rust/kernel/sync/condvar.rs index fbf68ada582f,c2535db9e0f8..caebf03f553b --- a/rust/kernel/sync/condvar.rs +++ b/rust/kernel/sync/condvar.rs @@@ -8,17 -8,14 +8,15 @@@ use super::{lock::Backend, lock::Guard, LockClassKey}; use crate::{ ffi::{c_int, c_long}, - init::PinInit, - pin_init, str::CStr, - task::{MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE, TASK_NORMAL, TASK_UNINTERRUPTIBLE}, + task::{ + MAX_SCHEDULE_TIMEOUT, TASK_FREEZABLE, TASK_INTERRUPTIBLE, TASK_NORMAL, TASK_UNINTERRUPTIBLE, + }, time::Jiffies, types::Opaque, }; -use core::marker::PhantomPinned; -use core::ptr; +use core::{marker::PhantomPinned, pin::Pin, ptr}; - use macros::pin_data; + use pin_init::{pin_data, pin_init, PinInit}; /// Creates a [`CondVar`] initialiser with the given name and a newly-created lock class. #[macro_export] diff --cc rust/kernel/sync/lock.rs index 360a10a9216d,7f611b59ac57..b69ed684df14 --- a/rust/kernel/sync/lock.rs +++ b/rust/kernel/sync/lock.rs @@@ -10,10 -10,8 +10,8 @@@ use crate:: str::CStr, types::{NotThreadSafe, Opaque, ScopeGuard}, }; -use core::{cell::UnsafeCell, marker::PhantomPinned}; +use core::{cell::UnsafeCell, marker::PhantomPinned, pin::Pin}; - use macros::pin_data; + use pin_init::{pin_data, pin_init, PinInit}; pub mod mutex; pub mod spinlock; diff --cc rust/pin-init/src/lib.rs index 000000000000,f36b8f8e8730..9cd822388ba2 mode 000000,100644..100644 --- a/rust/pin-init/src/lib.rs +++ b/rust/pin-init/src/lib.rs @@@ -1,0 -1,1486 +1,1484 @@@ + // SPDX-License-Identifier: Apache-2.0 OR MIT + + //! Library to safely and fallibly initialize pinned `struct`s using in-place constructors. + //! + //! [Pinning][pinning] is Rust's way of ensuring data does not move. + //! + //! It also allows in-place initialization of big `struct`s that would otherwise produce a stack + //! overflow. + //! + //! This library's main use-case is in [Rust-for-Linux]. Although this version can be used + //! standalone. + //! + //! There are cases when you want to in-place initialize a struct. For example when it is very big + //! and moving it from the stack is not an option, because it is bigger than the stack itself. + //! Another reason would be that you need the address of the object to initialize it. This stands + //! in direct conflict with Rust's normal process of first initializing an object and then moving + //! it into it's final memory location. For more information, see + //! <https://rust-for-linux.com/the-safe-pinned-initialization-problem>. + //! + //! This library allows you to do in-place initialization safely. + //! + //! ## Nightly Needed for `alloc` feature + //! + //! This library requires the [`allocator_api` unstable feature] when the `alloc` feature is + //! enabled and thus this feature can only be used with a nightly compiler. When enabling the + //! `alloc` feature, the user will be required to activate `allocator_api` as well. + //! + //! [`allocator_api` unstable feature]: https://doc.rust-lang.org/nightly/unstable-book/library-features/allocator-api.html + //! + //! The feature is enabled by default, thus by default `pin-init` will require a nightly compiler. + //! However, using the crate on stable compilers is possible by disabling `alloc`. In practice this + //! will require the `std` feature, because stable compilers have neither `Box` nor `Arc` in no-std + //! mode. + //! + //! # Overview + //! + //! To initialize a `struct` with an in-place constructor you will need two things: + //! - an in-place constructor, + //! - a memory location that can hold your `struct` (this can be the [stack], an [`Arc<T>`], + //! [`Box<T>`] or any other smart pointer that supports this library). + //! + //! To get an in-place constructor there are generally three options: + //! - directly creating an in-place constructor using the [`pin_init!`] macro, + //! - a custom function/macro returning an in-place constructor provided by someone else, + //! - using the unsafe function [`pin_init_from_closure()`] to manually create an initializer. + //! + //! Aside from pinned initialization, this library also supports in-place construction without + //! pinning, the macros/types/functions are generally named like the pinned variants without the + //! `pin_` prefix. + //! + //! # Examples + //! + //! Throughout the examples we will often make use of the `CMutex` type which can be found in + //! `../examples/mutex.rs`. It is essentially a userland rebuild of the `struct mutex` type from + //! the Linux kernel. It also uses a wait list and a basic spinlock. Importantly the wait list + //! requires it to be pinned to be locked and thus is a prime candidate for using this library. + //! + //! ## Using the [`pin_init!`] macro + //! + //! If you want to use [`PinInit`], then you will have to annotate your `struct` with + //! `#[`[`pin_data`]`]`. It is a macro that uses `#[pin]` as a marker for + //! [structurally pinned fields]. After doing this, you can then create an in-place constructor via + //! [`pin_init!`]. The syntax is almost the same as normal `struct` initializers. The difference is + //! that you need to write `<-` instead of `:` for fields that you want to initialize in-place. + //! + //! ```rust + //! # #![expect(clippy::disallowed_names)] + //! # #![feature(allocator_api)] + //! # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + //! # use core::pin::Pin; + //! use pin_init::{pin_data, pin_init, InPlaceInit}; + //! + //! #[pin_data] + //! struct Foo { + //! #[pin] + //! a: CMutex<usize>, + //! b: u32, + //! } + //! + //! let foo = pin_init!(Foo { + //! a <- CMutex::new(42), + //! b: 24, + //! }); + //! # let _ = Box::pin_init(foo); + //! ``` + //! + //! `foo` now is of the type [`impl PinInit<Foo>`]. We can now use any smart pointer that we like + //! (or just the stack) to actually initialize a `Foo`: + //! + //! ```rust + //! # #![expect(clippy::disallowed_names)] + //! # #![feature(allocator_api)] + //! # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + //! # use core::{alloc::AllocError, pin::Pin}; + //! # use pin_init::*; + //! # + //! # #[pin_data] + //! # struct Foo { + //! # #[pin] + //! # a: CMutex<usize>, + //! # b: u32, + //! # } + //! # + //! # let foo = pin_init!(Foo { + //! # a <- CMutex::new(42), + //! # b: 24, + //! # }); + //! let foo: Result<Pin<Box<Foo>>, AllocError> = Box::pin_init(foo); + //! ``` + //! + //! For more information see the [`pin_init!`] macro. + //! + //! ## Using a custom function/macro that returns an initializer + //! + //! Many types that use this library supply a function/macro that returns an initializer, because + //! the above method only works for types where you can access the fields. + //! + //! ```rust + //! # #![feature(allocator_api)] + //! # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + //! # use pin_init::*; + //! # use std::sync::Arc; + //! # use core::pin::Pin; + //! let mtx: Result<Pin<Arc<CMutex<usize>>>, _> = Arc::pin_init(CMutex::new(42)); + //! ``` + //! + //! To declare an init macro/function you just return an [`impl PinInit<T, E>`]: + //! + //! ```rust + //! # #![feature(allocator_api)] + //! # use pin_init::*; + //! # #[path = "../examples/error.rs"] mod error; use error::Error; + //! # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + //! #[pin_data] + //! struct DriverData { + //! #[pin] + //! status: CMutex<i32>, + //! buffer: Box<[u8; 1_000_000]>, + //! } + //! + //! impl DriverData { + //! fn new() -> impl PinInit<Self, Error> { + //! try_pin_init!(Self { + //! status <- CMutex::new(0), + //! buffer: Box::init(pin_init::zeroed())?, + //! }? Error) + //! } + //! } + //! ``` + //! + //! ## Manual creation of an initializer + //! + //! Often when working with primitives the previous approaches are not sufficient. That is where + //! [`pin_init_from_closure()`] comes in. This `unsafe` function allows you to create a + //! [`impl PinInit<T, E>`] directly from a closure. Of course you have to ensure that the closure + //! actually does the initialization in the correct way. Here are the things to look out for + //! (we are calling the parameter to the closure `slot`): + //! - when the closure returns `Ok(())`, then it has completed the initialization successfully, so + //! `slot` now contains a valid bit pattern for the type `T`, + //! - when the closure returns `Err(e)`, then the caller may deallocate the memory at `slot`, so + //! you need to take care to clean up anything if your initialization fails mid-way, + //! - you may assume that `slot` will stay pinned even after the closure returns until `drop` of + //! `slot` gets called. + //! + //! ```rust + //! # #![feature(extern_types)] + //! use pin_init::{pin_data, pinned_drop, PinInit, PinnedDrop, pin_init_from_closure}; + //! use core::{ + //! ptr::addr_of_mut, + //! marker::PhantomPinned, + //! cell::UnsafeCell, + //! pin::Pin, + //! mem::MaybeUninit, + //! }; + //! mod bindings { + //! #[repr(C)] + //! pub struct foo { + //! /* fields from C ... */ + //! } + //! extern "C" { + //! pub fn init_foo(ptr: *mut foo); + //! pub fn destroy_foo(ptr: *mut foo); + //! #[must_use = "you must check the error return code"] + //! pub fn enable_foo(ptr: *mut foo, flags: u32) -> i32; + //! } + //! } + //! + //! /// # Invariants + //! /// + //! /// `foo` is always initialized + //! #[pin_data(PinnedDrop)] + //! pub struct RawFoo { + //! #[pin] + //! _p: PhantomPinned, + //! #[pin] + //! foo: UnsafeCell<MaybeUninit<bindings::foo>>, + //! } + //! + //! impl RawFoo { + //! pub fn new(flags: u32) -> impl PinInit<Self, i32> { + //! // SAFETY: + //! // - when the closure returns `Ok(())`, then it has successfully initialized and + //! // enabled `foo`, + //! // - when it returns `Err(e)`, then it has cleaned up before + //! unsafe { + //! pin_init_from_closure(move |slot: *mut Self| { + //! // `slot` contains uninit memory, avoid creating a reference. + //! let foo = addr_of_mut!((*slot).foo); + //! let foo = UnsafeCell::raw_get(foo).cast::<bindings::foo>(); + //! + //! // Initialize the `foo` + //! bindings::init_foo(foo); + //! + //! // Try to enable it. + //! let err = bindings::enable_foo(foo, flags); + //! if err != 0 { + //! // Enabling has failed, first clean up the foo and then return the error. + //! bindings::destroy_foo(foo); + //! Err(err) + //! } else { + //! // All fields of `RawFoo` have been initialized, since `_p` is a ZST. + //! Ok(()) + //! } + //! }) + //! } + //! } + //! } + //! + //! #[pinned_drop] + //! impl PinnedDrop for RawFoo { + //! fn drop(self: Pin<&mut Self>) { + //! // SAFETY: Since `foo` is initialized, destroying is safe. + //! unsafe { bindings::destroy_foo(self.foo.get().cast::<bindings::foo>()) }; + //! } + //! } + //! ``` + //! + //! For more information on how to use [`pin_init_from_closure()`], take a look at the uses inside + //! the `kernel` crate. The [`sync`] module is a good starting point. + //! + //! [`sync`]: https://rust.docs.kernel.org/kernel/sync/index.html + //! [pinning]: https://doc.rust-lang.org/std/pin/index.html + //! [structurally pinned fields]: + //! https://doc.rust-lang.org/std/pin/index.html#pinning-is-structural-for-field + //! [stack]: crate::stack_pin_init + #![cfg_attr( + kernel, + doc = "[`Arc<T>`]: https://rust.docs.kernel.org/kernel/sync/struct.Arc.html"; + )] + #![cfg_attr( + kernel, + doc = "[`Box<T>`]: https://rust.docs.kernel.org/kernel/alloc/kbox/struct.Box.html"; + )] + #![cfg_attr(not(kernel), doc = "[`Arc<T>`]: alloc::alloc::sync::Arc")] + #![cfg_attr(not(kernel), doc = "[`Box<T>`]: alloc::alloc::boxed::Box")] + //! [`impl PinInit<Foo>`]: crate::PinInit + //! [`impl PinInit<T, E>`]: crate::PinInit + //! [`impl Init<T, E>`]: crate::Init + //! [Rust-for-Linux]: https://rust-for-linux.com/ + + #![cfg_attr(not(RUSTC_LINT_REASONS_IS_STABLE), feature(lint_reasons))] + #![cfg_attr( + all( + any(feature = "alloc", feature = "std"), + not(RUSTC_NEW_UNINIT_IS_STABLE) + ), + feature(new_uninit) + )] + #![forbid(missing_docs, unsafe_op_in_unsafe_fn)] + #![cfg_attr(not(feature = "std"), no_std)] + #![cfg_attr(feature = "alloc", feature(allocator_api))] + + use core::{ + cell::UnsafeCell, + convert::Infallible, + marker::PhantomData, + mem::MaybeUninit, + num::*, + pin::Pin, + ptr::{self, NonNull}, + }; + + #[doc(hidden)] + pub mod __internal; + #[doc(hidden)] + pub mod macros; + + #[cfg(any(feature = "std", feature = "alloc"))] + mod alloc; + #[cfg(any(feature = "std", feature = "alloc"))] + pub use alloc::InPlaceInit; + + /// Used to specify the pinning information of the fields of a struct. + /// + /// This is somewhat similar in purpose as + /// [pin-project-lite](https://crates.io/crates/pin-project-lite). + /// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each + /// field you want to structurally pin. + /// + /// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`, + /// then `#[pin]` directs the type of initializer that is required. + /// + /// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this + /// macro, and change your `Drop` implementation to `PinnedDrop` annotated with + /// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care. + /// + /// # Examples + /// + /// ``` + /// # #![feature(allocator_api)] + /// # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + /// use pin_init::pin_data; + /// + /// enum Command { + /// /* ... */ + /// } + /// + /// #[pin_data] + /// struct DriverData { + /// #[pin] + /// queue: CMutex<Vec<Command>>, + /// buf: Box<[u8; 1024 * 1024]>, + /// } + /// ``` + /// + /// ``` + /// # #![feature(allocator_api)] + /// # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + /// # mod bindings { pub struct info; pub unsafe fn destroy_info(_: *mut info) {} } + /// use core::pin::Pin; + /// use pin_init::{pin_data, pinned_drop, PinnedDrop}; + /// + /// enum Command { + /// /* ... */ + /// } + /// + /// #[pin_data(PinnedDrop)] + /// struct DriverData { + /// #[pin] + /// queue: CMutex<Vec<Command>>, + /// buf: Box<[u8; 1024 * 1024]>, + /// raw_info: *mut bindings::info, + /// } + /// + /// #[pinned_drop] + /// impl PinnedDrop for DriverData { + /// fn drop(self: Pin<&mut Self>) { + /// unsafe { bindings::destroy_info(self.raw_info) }; + /// } + /// } + /// ``` + pub use ::pin_init_internal::pin_data; + + /// Used to implement `PinnedDrop` safely. + /// + /// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`. + /// + /// # Examples + /// + /// ``` + /// # #![feature(allocator_api)] + /// # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + /// # mod bindings { pub struct info; pub unsafe fn destroy_info(_: *mut info) {} } + /// use core::pin::Pin; + /// use pin_init::{pin_data, pinned_drop, PinnedDrop}; + /// + /// enum Command { + /// /* ... */ + /// } + /// + /// #[pin_data(PinnedDrop)] + /// struct DriverData { + /// #[pin] + /// queue: CMutex<Vec<Command>>, + /// buf: Box<[u8; 1024 * 1024]>, + /// raw_info: *mut bindings::info, + /// } + /// + /// #[pinned_drop] + /// impl PinnedDrop for DriverData { + /// fn drop(self: Pin<&mut Self>) { + /// unsafe { bindings::destroy_info(self.raw_info) }; + /// } + /// } + /// ``` + pub use ::pin_init_internal::pinned_drop; + + /// Derives the [`Zeroable`] trait for the given struct. + /// + /// This can only be used for structs where every field implements the [`Zeroable`] trait. + /// + /// # Examples + /// + /// ``` + /// use pin_init::Zeroable; + /// + /// #[derive(Zeroable)] + /// pub struct DriverData { + /// id: i64, + /// buf_ptr: *mut u8, + /// len: usize, + /// } + /// ``` + pub use ::pin_init_internal::Zeroable; + + /// Initialize and pin a type directly on the stack. + /// + /// # Examples + /// + /// ```rust + /// # #![expect(clippy::disallowed_names)] + /// # #![feature(allocator_api)] + /// # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + /// # use pin_init::*; + /// # use core::pin::Pin; + /// #[pin_data] + /// struct Foo { + /// #[pin] + /// a: CMutex<usize>, + /// b: Bar, + /// } + /// + /// #[pin_data] + /// struct Bar { + /// x: u32, + /// } + /// + /// stack_pin_init!(let foo = pin_init!(Foo { + /// a <- CMutex::new(42), + /// b: Bar { + /// x: 64, + /// }, + /// })); + /// let foo: Pin<&mut Foo> = foo; + /// println!("a: {}", &*foo.a.lock()); + /// ``` + /// + /// # Syntax + /// + /// A normal `let` binding with optional type annotation. The expression is expected to implement + /// [`PinInit`]/[`Init`] with the error type [`Infallible`]. If you want to use a different error + /// type, then use [`stack_try_pin_init!`]. + #[macro_export] + macro_rules! stack_pin_init { + (let $var:ident $(: $t:ty)? = $val:expr) => { + let val = $val; + let mut $var = ::core::pin::pin!($crate::__internal::StackInit$(::<$t>)?::uninit()); + let mut $var = match $crate::__internal::StackInit::init($var, val) { + Ok(res) => res, + Err(x) => { + let x: ::core::convert::Infallible = x; + match x {} + } + }; + }; + } + + /// Initialize and pin a type directly on the stack. + /// + /// # Examples + /// + /// ```rust + /// # #![expect(clippy::disallowed_names)] + /// # #![feature(allocator_api)] + /// # #[path = "../examples/error.rs"] mod error; use error::Error; + /// # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + /// # use pin_init::*; + /// #[pin_data] + /// struct Foo { + /// #[pin] + /// a: CMutex<usize>, + /// b: Box<Bar>, + /// } + /// + /// struct Bar { + /// x: u32, + /// } + /// + /// stack_try_pin_init!(let foo: Foo = try_pin_init!(Foo { + /// a <- CMutex::new(42), + /// b: Box::try_new(Bar { + /// x: 64, + /// })?, + /// }? Error)); + /// let foo = foo.unwrap(); + /// println!("a: {}", &*foo.a.lock()); + /// ``` + /// + /// ```rust + /// # #![expect(clippy::disallowed_names)] + /// # #![feature(allocator_api)] + /// # #[path = "../examples/error.rs"] mod error; use error::Error; + /// # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + /// # use pin_init::*; + /// #[pin_data] + /// struct Foo { + /// #[pin] + /// a: CMutex<usize>, + /// b: Box<Bar>, + /// } + /// + /// struct Bar { + /// x: u32, + /// } + /// + /// stack_try_pin_init!(let foo: Foo =? try_pin_init!(Foo { + /// a <- CMutex::new(42), + /// b: Box::try_new(Bar { + /// x: 64, + /// })?, + /// }? Error)); + /// println!("a: {}", &*foo.a.lock()); + /// # Ok::<_, Error>(()) + /// ``` + /// + /// # Syntax + /// + /// A normal `let` binding with optional type annotation. The expression is expected to implement + /// [`PinInit`]/[`Init`]. This macro assigns a result to the given variable, adding a `?` after the + /// `=` will propagate this error. + #[macro_export] + macro_rules! stack_try_pin_init { + (let $var:ident $(: $t:ty)? = $val:expr) => { + let val = $val; + let mut $var = ::core::pin::pin!($crate::__internal::StackInit$(::<$t>)?::uninit()); + let mut $var = $crate::__internal::StackInit::init($var, val); + }; + (let $var:ident $(: $t:ty)? =? $val:expr) => { + let val = $val; + let mut $var = ::core::pin::pin!($crate::__internal::StackInit$(::<$t>)?::uninit()); + let mut $var = $crate::__internal::StackInit::init($var, val)?; + }; + } + + /// Construct an in-place, pinned initializer for `struct`s. + /// + /// This macro defaults the error to [`Infallible`]. If you need a different error, then use + /// [`try_pin_init!`]. + /// + /// The syntax is almost identical to that of a normal `struct` initializer: + /// + /// ```rust + /// # use pin_init::*; + /// # use core::pin::Pin; + /// #[pin_data] + /// struct Foo { + /// a: usize, + /// b: Bar, + /// } + /// + /// #[pin_data] + /// struct Bar { + /// x: u32, + /// } + /// + /// # fn demo() -> impl PinInit<Foo> { + /// let a = 42; + /// + /// let initializer = pin_init!(Foo { + /// a, + /// b: Bar { + /// x: 64, + /// }, + /// }); + /// # initializer } + /// # Box::pin_init(demo()).unwrap(); + /// ``` + /// + /// Arbitrary Rust expressions can be used to set the value of a variable. + /// + /// The fields are initialized in the order that they appear in the initializer. So it is possible + /// to read already initialized fields using raw pointers. + /// + /// IMPORTANT: You are not allowed to create references to fields of the struct inside of the + /// initializer. + /// + /// # Init-functions + /// + /// When working with this library it is often desired to let others construct your types without + /// giving access to all fields. This is where you would normally write a plain function `new` that + /// would return a new instance of your type. With this library that is also possible. However, + /// there are a few extra things to keep in mind. + /// + /// To create an initializer function, simply declare it like this: + /// + /// ```rust + /// # use pin_init::*; + /// # use core::pin::Pin; + /// # #[pin_data] + /// # struct Foo { + /// # a: usize, + /// # b: Bar, + /// # } + /// # #[pin_data] + /// # struct Bar { + /// # x: u32, + /// # } + /// impl Foo { + /// fn new() -> impl PinInit<Self> { + /// pin_init!(Self { + /// a: 42, + /// b: Bar { + /// x: 64, + /// }, + /// }) + /// } + /// } + /// ``` + /// + /// Users of `Foo` can now create it like this: + /// + /// ```rust + /// # #![expect(clippy::disallowed_names)] + /// # use pin_init::*; + /// # use core::pin::Pin; + /// # #[pin_data] + /// # struct Foo { + /// # a: usize, + /// # b: Bar, + /// # } + /// # #[pin_data] + /// # struct Bar { + /// # x: u32, + /// # } + /// # impl Foo { + /// # fn new() -> impl PinInit<Self> { + /// # pin_init!(Self { + /// # a: 42, + /// # b: Bar { + /// # x: 64, + /// # }, + /// # }) + /// # } + /// # } + /// let foo = Box::pin_init(Foo::new()); + /// ``` + /// + /// They can also easily embed it into their own `struct`s: + /// + /// ```rust + /// # use pin_init::*; + /// # use core::pin::Pin; + /// # #[pin_data] + /// # struct Foo { + /// # a: usize, + /// # b: Bar, + /// # } + /// # #[pin_data] + /// # struct Bar { + /// # x: u32, + /// # } + /// # impl Foo { + /// # fn new() -> impl PinInit<Self> { + /// # pin_init!(Self { + /// # a: 42, + /// # b: Bar { + /// # x: 64, + /// # }, + /// # }) + /// # } + /// # } + /// #[pin_data] + /// struct FooContainer { + /// #[pin] + /// foo1: Foo, + /// #[pin] + /// foo2: Foo, + /// other: u32, + /// } + /// + /// impl FooContainer { + /// fn new(other: u32) -> impl PinInit<Self> { + /// pin_init!(Self { + /// foo1 <- Foo::new(), + /// foo2 <- Foo::new(), + /// other, + /// }) + /// } + /// } + /// ``` + /// + /// Here we see that when using `pin_init!` with `PinInit`, one needs to write `<-` instead of `:`. + /// This signifies that the given field is initialized in-place. As with `struct` initializers, just + /// writing the field (in this case `other`) without `:` or `<-` means `other: other,`. + /// + /// # Syntax + /// + /// As already mentioned in the examples above, inside of `pin_init!` a `struct` initializer with + /// the following modifications is expected: + /// - Fields that you want to initialize in-place have to use `<-` instead of `:`. + /// - In front of the initializer you can write `&this in` to have access to a [`NonNull<Self>`] + /// pointer named `this` inside of the initializer. + /// - Using struct update syntax one can place `..Zeroable::zeroed()` at the very end of the + /// struct, this initializes every field with 0 and then runs all initializers specified in the + /// body. This can only be done if [`Zeroable`] is implemented for the struct. + /// + /// For instance: + /// + /// ```rust + /// # use pin_init::*; + /// # use core::{ptr::addr_of_mut, marker::PhantomPinned}; + /// #[pin_data] + /// #[derive(Zeroable)] + /// struct Buf { + /// // `ptr` points into `buf`. + /// ptr: *mut u8, + /// buf: [u8; 64], + /// #[pin] + /// pin: PhantomPinned, + /// } + /// + /// let init = pin_init!(&this in Buf { + /// buf: [0; 64], + /// // SAFETY: TODO. + /// ptr: unsafe { addr_of_mut!((*this.as_ptr()).buf).cast() }, + /// pin: PhantomPinned, + /// }); + /// let init = pin_init!(Buf { + /// buf: [1; 64], + /// ..Zeroable::zeroed() + /// }); + /// ``` + /// + /// [`NonNull<Self>`]: core::ptr::NonNull + // For a detailed example of how this macro works, see the module documentation of the hidden + // module `macros` inside of `macros.rs`. + #[macro_export] + macro_rules! pin_init { + ($(&$this:ident in)? $t:ident $(::<$($generics:ty),* $(,)?>)? { + $($fields:tt)* + }) => { + $crate::try_pin_init!($(&$this in)? $t $(::<$($generics),*>)? { + $($fields)* + }? ::core::convert::Infallible) + }; + } + + /// Construct an in-place, fallible pinned initializer for `struct`s. + /// + /// If the initialization can complete without error (or [`Infallible`]), then use [`pin_init!`]. + /// + /// You can use the `?` operator or use `return Err(err)` inside the initializer to stop + /// initialization and return the error. + /// + /// IMPORTANT: if you have `unsafe` code inside of the initializer you have to ensure that when + /// initialization fails, the memory can be safely deallocated without any further modifications. + /// + /// The syntax is identical to [`pin_init!`] with the following exception: you must append `? $type` + /// after the `struct` initializer to specify the error type you want to use. + /// + /// # Examples + /// + /// ```rust + /// # #![feature(allocator_api)] + /// # #[path = "../examples/error.rs"] mod error; use error::Error; + /// use pin_init::{pin_data, try_pin_init, PinInit, InPlaceInit, zeroed}; + /// + /// #[pin_data] + /// struct BigBuf { + /// big: Box<[u8; 1024 * 1024 * 1024]>, + /// small: [u8; 1024 * 1024], + /// ptr: *mut u8, + /// } + /// + /// impl BigBuf { + /// fn new() -> impl PinInit<Self, Error> { + /// try_pin_init!(Self { + /// big: Box::init(zeroed())?, + /// small: [0; 1024 * 1024], + /// ptr: core::ptr::null_mut(), + /// }? Error) + /// } + /// } + /// # let _ = Box::pin_init(BigBuf::new()); + /// ``` + // For a detailed example of how this macro works, see the module documentation of the hidden + // module `macros` inside of `macros.rs`. + #[macro_export] + macro_rules! try_pin_init { + ($(&$this:ident in)? $t:ident $(::<$($generics:ty),* $(,)?>)? { + $($fields:tt)* + }? $err:ty) => { + $crate::__init_internal!( + @this($($this)?), + @typ($t $(::<$($generics),*>)? ), + @fields($($fields)*), + @error($err), + @data(PinData, use_data), + @has_data(HasPinData, __pin_data), + @construct_closure(pin_init_from_closure), + @munch_fields($($fields)*), + ) + } + } + + /// Construct an in-place initializer for `struct`s. + /// + /// This macro defaults the error to [`Infallible`]. If you need a different error, then use + /// [`try_init!`]. + /// + /// The syntax is identical to [`pin_init!`] and its safety caveats also apply: + /// - `unsafe` code must guarantee either full initialization or return an error and allow + /// deallocation of the memory. + /// - the fields are initialized in the order given in the initializer. + /// - no references to fields are allowed to be created inside of the initializer. + /// + /// This initializer is for initializing data in-place that might later be moved. If you want to + /// pin-initialize, use [`pin_init!`]. + /// + /// # Examples + /// + /// ```rust + /// # #![feature(allocator_api)] + /// # #[path = "../examples/error.rs"] mod error; use error::Error; + /// # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + /// # use pin_init::InPlaceInit; + /// use pin_init::{init, Init, zeroed}; + /// + /// struct BigBuf { + /// small: [u8; 1024 * 1024], + /// } + /// + /// impl BigBuf { + /// fn new() -> impl Init<Self> { + /// init!(Self { + /// small <- zeroed(), + /// }) + /// } + /// } + /// # let _ = Box::init(BigBuf::new()); + /// ``` + // For a detailed example of how this macro works, see the module documentation of the hidden + // module `macros` inside of `macros.rs`. + #[macro_export] + macro_rules! init { + ($(&$this:ident in)? $t:ident $(::<$($generics:ty),* $(,)?>)? { + $($fields:tt)* + }) => { + $crate::try_init!($(&$this in)? $t $(::<$($generics),*>)? { + $($fields)* + }? ::core::convert::Infallible) + } + } + + /// Construct an in-place fallible initializer for `struct`s. + /// + /// If the initialization can complete without error (or [`Infallible`]), then use + /// [`init!`]. + /// + /// The syntax is identical to [`try_pin_init!`]. You need to specify a custom error + /// via `? $type` after the `struct` initializer. + /// The safety caveats from [`try_pin_init!`] also apply: + /// - `unsafe` code must guarantee either full initialization or return an error and allow + /// deallocation of the memory. + /// - the fields are initialized in the order given in the initializer. + /// - no references to fields are allowed to be created inside of the initializer. + /// + /// # Examples + /// + /// ```rust + /// # #![feature(allocator_api)] + /// # use core::alloc::AllocError; + /// # use pin_init::InPlaceInit; + /// use pin_init::{try_init, Init, zeroed}; + /// + /// struct BigBuf { + /// big: Box<[u8; 1024 * 1024 * 1024]>, + /// small: [u8; 1024 * 1024], + /// } + /// + /// impl BigBuf { + /// fn new() -> impl Init<Self, AllocError> { + /// try_init!(Self { + /// big: Box::init(zeroed())?, + /// small: [0; 1024 * 1024], + /// }? AllocError) + /// } + /// } + /// # let _ = Box::init(BigBuf::new()); + /// ``` + // For a detailed example of how this macro works, see the module documentation of the hidden + // module `macros` inside of `macros.rs`. + #[macro_export] + macro_rules! try_init { + ($(&$this:ident in)? $t:ident $(::<$($generics:ty),* $(,)?>)? { + $($fields:tt)* + }? $err:ty) => { + $crate::__init_internal!( + @this($($this)?), + @typ($t $(::<$($generics),*>)?), + @fields($($fields)*), + @error($err), + @data(InitData, /*no use_data*/), + @has_data(HasInitData, __init_data), + @construct_closure(init_from_closure), + @munch_fields($($fields)*), + ) + } + } + + /// Asserts that a field on a struct using `#[pin_data]` is marked with `#[pin]` ie. that it is + /// structurally pinned. + /// + /// # Example + /// + /// This will succeed: + /// ``` + /// use pin_init::{pin_data, assert_pinned}; + /// + /// #[pin_data] + /// struct MyStruct { + /// #[pin] + /// some_field: u64, + /// } + /// + /// assert_pinned!(MyStruct, some_field, u64); + /// ``` + /// + /// This will fail: + /// ```compile_fail + /// use pin_init::{pin_data, assert_pinned}; + /// + /// #[pin_data] + /// struct MyStruct { + /// some_field: u64, + /// } + /// + /// assert_pinned!(MyStruct, some_field, u64); + /// ``` + /// + /// Some uses of the macro may trigger the `can't use generic parameters from outer item` error. To + /// work around this, you may pass the `inline` parameter to the macro. The `inline` parameter can + /// only be used when the macro is invoked from a function body. + /// ``` + /// # use core::pin::Pin; + /// use pin_init::{pin_data, assert_pinned}; + /// + /// #[pin_data] + /// struct Foo<T> { + /// #[pin] + /// elem: T, + /// } + /// + /// impl<T> Foo<T> { + /// fn project(self: Pin<&mut Self>) -> Pin<&mut T> { + /// assert_pinned!(Foo<T>, elem, T, inline); + /// + /// // SAFETY: The field is structurally pinned. + /// unsafe { self.map_unchecked_mut(|me| &mut me.elem) } + /// } + /// } + /// ``` + #[macro_export] + macro_rules! assert_pinned { + ($ty:ty, $field:ident, $field_ty:ty, inline) => { + let _ = move |ptr: *mut $field_ty| { + // SAFETY: This code is unreachable. + let data = unsafe { <$ty as $crate::__internal::HasPinData>::__pin_data() }; + let init = $crate::__internal::AlwaysFail::<$field_ty>::new(); + // SAFETY: This code is unreachable. + unsafe { data.$field(ptr, init) }.ok(); + }; + }; + + ($ty:ty, $field:ident, $field_ty:ty) => { + const _: () = { + $crate::assert_pinned!($ty, $field, $field_ty, inline); + }; + }; + } + + /// A pin-initializer for the type `T`. + /// + /// To use this initializer, you will need a suitable memory location that can hold a `T`. This can + /// be [`Box<T>`], [`Arc<T>`] or even the stack (see [`stack_pin_init!`]). + /// + /// Also see the [module description](self). + /// + /// # Safety + /// + /// When implementing this trait you will need to take great care. Also there are probably very few + /// cases where a manual implementation is necessary. Use [`pin_init_from_closure`] where possible. + /// + /// The [`PinInit::__pinned_init`] function: + /// - returns `Ok(())` if it initialized every field of `slot`, + /// - returns `Err(err)` if it encountered an error and then cleaned `slot`, this means: + /// - `slot` can be deallocated without UB occurring, + /// - `slot` does not need to be dropped, + /// - `slot` is not partially initialized. + /// - while constructing the `T` at `slot` it upholds the pinning invariants of `T`. + /// + #[cfg_attr( + kernel, + doc = "[`Arc<T>`]: https://rust.docs.kernel.org/kernel/sync/struct.Arc.html"; + )] + #[cfg_attr( + kernel, + doc = "[`Box<T>`]: https://rust.docs.kernel.org/kernel/alloc/kbox/struct.Box.html"; + )] + #[cfg_attr(not(kernel), doc = "[`Arc<T>`]: alloc::alloc::sync::Arc")] + #[cfg_attr(not(kernel), doc = "[`Box<T>`]: alloc::alloc::boxed::Box")] + #[must_use = "An initializer must be used in order to create its value."] + pub unsafe trait PinInit<T: ?Sized, E = Infallible>: Sized { + /// Initializes `slot`. + /// + /// # Safety + /// + /// - `slot` is a valid pointer to uninitialized memory. + /// - the caller does not touch `slot` when `Err` is returned, they are only permitted to + /// deallocate. + /// - `slot` will not move until it is dropped, i.e. it will be pinned. + unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E>; + + /// First initializes the value using `self` then calls the function `f` with the initialized + /// value. + /// + /// If `f` returns an error the value is dropped and the initializer will forward the error. + /// + /// # Examples + /// + /// ```rust + /// # #![feature(allocator_api)] + /// # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + /// # use pin_init::*; + /// let mtx_init = CMutex::new(42); + /// // Make the initializer print the value. + /// let mtx_init = mtx_init.pin_chain(|mtx| { + /// println!("{:?}", mtx.get_data_mut()); + /// Ok(()) + /// }); + /// ``` + fn pin_chain<F>(self, f: F) -> ChainPinInit<Self, F, T, E> + where + F: FnOnce(Pin<&mut T>) -> Result<(), E>, + { + ChainPinInit(self, f, PhantomData) + } + } + + /// An initializer returned by [`PinInit::pin_chain`]. + pub struct ChainPinInit<I, F, T: ?Sized, E>(I, F, __internal::Invariant<(E, T)>); + + // SAFETY: The `__pinned_init` function is implemented such that it + // - returns `Ok(())` on successful initialization, + // - returns `Err(err)` on error and in this case `slot` will be dropped. + // - considers `slot` pinned. + unsafe impl<T: ?Sized, E, I, F> PinInit<T, E> for ChainPinInit<I, F, T, E> + where + I: PinInit<T, E>, + F: FnOnce(Pin<&mut T>) -> Result<(), E>, + { + unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E> { + // SAFETY: All requirements fulfilled since this function is `__pinned_init`. + unsafe { self.0.__pinned_init(slot)? }; + // SAFETY: The above call initialized `slot` and we still have unique access. + let val = unsafe { &mut *slot }; + // SAFETY: `slot` is considered pinned. + let val = unsafe { Pin::new_unchecked(val) }; + // SAFETY: `slot` was initialized above. + (self.1)(val).inspect_err(|_| unsafe { core::ptr::drop_in_place(slot) }) + } + } + + /// An initializer for `T`. + /// + /// To use this initializer, you will need a suitable memory location that can hold a `T`. This can + /// be [`Box<T>`], [`Arc<T>`] or even the stack (see [`stack_pin_init!`]). Because + /// [`PinInit<T, E>`] is a super trait, you can use every function that takes it as well. + /// + /// Also see the [module description](self). + /// + /// # Safety + /// + /// When implementing this trait you will need to take great care. Also there are probably very few + /// cases where a manual implementation is necessary. Use [`init_from_closure`] where possible. + /// + /// The [`Init::__init`] function: + /// - returns `Ok(())` if it initialized every field of `slot`, + /// - returns `Err(err)` if it encountered an error and then cleaned `slot`, this means: + /// - `slot` can be deallocated without UB occurring, + /// - `slot` does not need to be dropped, + /// - `slot` is not partially initialized. + /// - while constructing the `T` at `slot` it upholds the pinning invariants of `T`. + /// + /// The `__pinned_init` function from the supertrait [`PinInit`] needs to execute the exact same + /// code as `__init`. + /// + /// Contrary to its supertype [`PinInit<T, E>`] the caller is allowed to + /// move the pointee after initialization. + /// + #[cfg_attr( + kernel, + doc = "[`Arc<T>`]: https://rust.docs.kernel.org/kernel/sync/struct.Arc.html"; + )] + #[cfg_attr( + kernel, + doc = "[`Box<T>`]: https://rust.docs.kernel.org/kernel/alloc/kbox/struct.Box.html"; + )] + #[cfg_attr(not(kernel), doc = "[`Arc<T>`]: alloc::alloc::sync::Arc")] + #[cfg_attr(not(kernel), doc = "[`Box<T>`]: alloc::alloc::boxed::Box")] + #[must_use = "An initializer must be used in order to create its value."] + pub unsafe trait Init<T: ?Sized, E = Infallible>: PinInit<T, E> { + /// Initializes `slot`. + /// + /// # Safety + /// + /// - `slot` is a valid pointer to uninitialized memory. + /// - the caller does not touch `slot` when `Err` is returned, they are only permitted to + /// deallocate. + unsafe fn __init(self, slot: *mut T) -> Result<(), E>; + + /// First initializes the value using `self` then calls the function `f` with the initialized + /// value. + /// + /// If `f` returns an error the value is dropped and the initializer will forward the error. + /// + /// # Examples + /// + /// ```rust + /// # #![expect(clippy::disallowed_names)] + /// use pin_init::{init, zeroed, Init}; + /// + /// struct Foo { + /// buf: [u8; 1_000_000], + /// } + /// + /// impl Foo { + /// fn setup(&mut self) { + /// println!("Setting up foo"); + /// } + /// } + /// + /// let foo = init!(Foo { + /// buf <- zeroed() + /// }).chain(|foo| { + /// foo.setup(); + /// Ok(()) + /// }); + /// ``` + fn chain<F>(self, f: F) -> ChainInit<Self, F, T, E> + where + F: FnOnce(&mut T) -> Result<(), E>, + { + ChainInit(self, f, PhantomData) + } + } + + /// An initializer returned by [`Init::chain`]. + pub struct ChainInit<I, F, T: ?Sized, E>(I, F, __internal::Invariant<(E, T)>); + + // SAFETY: The `__init` function is implemented such that it + // - returns `Ok(())` on successful initialization, + // - returns `Err(err)` on error and in this case `slot` will be dropped. + unsafe impl<T: ?Sized, E, I, F> Init<T, E> for ChainInit<I, F, T, E> + where + I: Init<T, E>, + F: FnOnce(&mut T) -> Result<(), E>, + { + unsafe fn __init(self, slot: *mut T) -> Result<(), E> { + // SAFETY: All requirements fulfilled since this function is `__init`. + unsafe { self.0.__pinned_init(slot)? }; + // SAFETY: The above call initialized `slot` and we still have unique access. + (self.1)(unsafe { &mut *slot }).inspect_err(|_| + // SAFETY: `slot` was initialized above. + unsafe { core::ptr::drop_in_place(slot) }) + } + } + + // SAFETY: `__pinned_init` behaves exactly the same as `__init`. + unsafe impl<T: ?Sized, E, I, F> PinInit<T, E> for ChainInit<I, F, T, E> + where + I: Init<T, E>, + F: FnOnce(&mut T) -> Result<(), E>, + { + unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E> { + // SAFETY: `__init` has less strict requirements compared to `__pinned_init`. + unsafe { self.__init(slot) } + } + } + + /// Creates a new [`PinInit<T, E>`] from the given closure. + /// + /// # Safety + /// + /// The closure: + /// - returns `Ok(())` if it initialized every field of `slot`, + /// - returns `Err(err)` if it encountered an error and then cleaned `slot`, this means: + /// - `slot` can be deallocated without UB occurring, + /// - `slot` does not need to be dropped, + /// - `slot` is not partially initialized. + /// - may assume that the `slot` does not move if `T: !Unpin`, + /// - while constructing the `T` at `slot` it upholds the pinning invariants of `T`. + #[inline] + pub const unsafe fn pin_init_from_closure<T: ?Sized, E>( + f: impl FnOnce(*mut T) -> Result<(), E>, + ) -> impl PinInit<T, E> { + __internal::InitClosure(f, PhantomData) + } + + /// Creates a new [`Init<T, E>`] from the given closure. + /// + /// # Safety + /// + /// The closure: + /// - returns `Ok(())` if it initialized every field of `slot`, + /// - returns `Err(err)` if it encountered an error and then cleaned `slot`, this means: + /// - `slot` can be deallocated without UB occurring, + /// - `slot` does not need to be dropped, + /// - `slot` is not partially initialized. + /// - the `slot` may move after initialization. + /// - while constructing the `T` at `slot` it upholds the pinning invariants of `T`. + #[inline] + pub const unsafe fn init_from_closure<T: ?Sized, E>( + f: impl FnOnce(*mut T) -> Result<(), E>, + ) -> impl Init<T, E> { + __internal::InitClosure(f, PhantomData) + } + + /// An initializer that leaves the memory uninitialized. + /// + /// The initializer is a no-op. The `slot` memory is not changed. + #[inline] + pub fn uninit<T, E>() -> impl Init<MaybeUninit<T>, E> { + // SAFETY: The memory is allowed to be uninitialized. + unsafe { init_from_closure(|_| Ok(())) } + } + + /// Initializes an array by initializing each element via the provided initializer. + /// + /// # Examples + /// + /// ```rust + /// # use pin_init::*; + /// use pin_init::init_array_from_fn; + /// let array: Box<[usize; 1_000]> = Box::init(init_array_from_fn(|i| i)).unwrap(); + /// assert_eq!(array.len(), 1_000); + /// ``` + pub fn init_array_from_fn<I, const N: usize, T, E>( + mut make_init: impl FnMut(usize) -> I, + ) -> impl Init<[T; N], E> + where + I: Init<T, E>, + { + let init = move |slot: *mut [T; N]| { + let slot = slot.cast::<T>(); + for i in 0..N { + let init = make_init(i); + // SAFETY: Since 0 <= `i` < N, it is still in bounds of `[T; N]`. + let ptr = unsafe { slot.add(i) }; + // SAFETY: The pointer is derived from `slot` and thus satisfies the `__init` + // requirements. + if let Err(e) = unsafe { init.__init(ptr) } { + // SAFETY: The loop has initialized the elements `slot[0..i]` and since we return + // `Err` below, `slot` will be considered uninitialized memory. + unsafe { ptr::drop_in_place(ptr::slice_from_raw_parts_mut(slot, i)) }; + return Err(e); + } + } + Ok(()) + }; + // SAFETY: The initializer above initializes every element of the array. On failure it drops + // any initialized elements and returns `Err`. + unsafe { init_from_closure(init) } + } + + /// Initializes an array by initializing each element via the provided initializer. + /// + /// # Examples + /// + /// ```rust + /// # #![feature(allocator_api)] + /// # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + /// # use pin_init::*; + /// # use core::pin::Pin; + /// use pin_init::pin_init_array_from_fn; + /// use std::sync::Arc; + /// let array: Pin<Arc<[CMutex<usize>; 1_000]>> = + /// Arc::pin_init(pin_init_array_from_fn(|i| CMutex::new(i))).unwrap(); + /// assert_eq!(array.len(), 1_000); + /// ``` + pub fn pin_init_array_from_fn<I, const N: usize, T, E>( + mut make_init: impl FnMut(usize) -> I, + ) -> impl PinInit<[T; N], E> + where + I: PinInit<T, E>, + { + let init = move |slot: *mut [T; N]| { + let slot = slot.cast::<T>(); + for i in 0..N { + let init = make_init(i); + // SAFETY: Since 0 <= `i` < N, it is still in bounds of `[T; N]`. + let ptr = unsafe { slot.add(i) }; + // SAFETY: The pointer is derived from `slot` and thus satisfies the `__init` + // requirements. + if let Err(e) = unsafe { init.__pinned_init(ptr) } { + // SAFETY: The loop has initialized the elements `slot[0..i]` and since we return + // `Err` below, `slot` will be considered uninitialized memory. + unsafe { ptr::drop_in_place(ptr::slice_from_raw_parts_mut(slot, i)) }; + return Err(e); + } + } + Ok(()) + }; + // SAFETY: The initializer above initializes every element of the array. On failure it drops + // any initialized elements and returns `Err`. + unsafe { pin_init_from_closure(init) } + } + + // SAFETY: Every type can be initialized by-value. + unsafe impl<T, E> Init<T, E> for T { + unsafe fn __init(self, slot: *mut T) -> Result<(), E> { + // SAFETY: TODO. + unsafe { slot.write(self) }; + Ok(()) + } + } + + // SAFETY: Every type can be initialized by-value. `__pinned_init` calls `__init`. + unsafe impl<T, E> PinInit<T, E> for T { + unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E> { + // SAFETY: TODO. + unsafe { self.__init(slot) } + } + } + + /// Smart pointer containing uninitialized memory and that can write a value. + pub trait InPlaceWrite<T> { + /// The type `Self` turns into when the contents are initialized. + type Initialized; + + /// Use the given initializer to write a value into `self`. + /// + /// Does not drop the current value and considers it as uninitialized memory. + fn write_init<E>(self, init: impl Init<T, E>) -> Result<Self::Initialized, E>; + + /// Use the given pin-initializer to write a value into `self`. + /// + /// Does not drop the current value and considers it as uninitialized memory. + fn write_pin_init<E>(self, init: impl PinInit<T, E>) -> Result<Pin<Self::Initialized>, E>; + } + + /// Trait facilitating pinned destruction. + /// + /// Use [`pinned_drop`] to implement this trait safely: + /// + /// ```rust + /// # #![feature(allocator_api)] + /// # #[path = "../examples/mutex.rs"] mod mutex; use mutex::*; + /// # use pin_init::*; + /// use core::pin::Pin; + /// #[pin_data(PinnedDrop)] + /// struct Foo { + /// #[pin] + /// mtx: CMutex<usize>, + /// } + /// + /// #[pinned_drop] + /// impl PinnedDrop for Foo { + /// fn drop(self: Pin<&mut Self>) { + /// println!("Foo is being dropped!"); + /// } + /// } + /// ``` + /// + /// # Safety + /// + /// This trait must be implemented via the [`pinned_drop`] proc-macro attribute on the impl. + pub unsafe trait PinnedDrop: __internal::HasPinData { + /// Executes the pinned destructor of this type. + /// + /// While this function is marked safe, it is actually unsafe to call it manually. For this + /// reason it takes an additional parameter. This type can only be constructed by `unsafe` code + /// and thus prevents this function from being called where it should not. + /// + /// This extra parameter will be generated by the `#[pinned_drop]` proc-macro attribute + /// automatically. + fn drop(self: Pin<&mut Self>, only_call_from_drop: __internal::OnlyCallFromDrop); + } + + /// Marker trait for types that can be initialized by writing just zeroes. + /// + /// # Safety + /// + /// The bit pattern consisting of only zeroes is a valid bit pattern for this type. In other words, + /// this is not UB: + /// + /// ```rust,ignore + /// let val: Self = unsafe { core::mem::zeroed() }; + /// ``` + pub unsafe trait Zeroable {} + + /// Marker trait for types that allow `Option<Self>` to be set to all zeroes in order to write + /// `None` to that location. + /// + /// # Safety + /// + /// The implementer needs to ensure that `unsafe impl Zeroable for Option<Self> {}` is sound. + pub unsafe trait ZeroableOption {} + + // SAFETY: by the safety requirement of `ZeroableOption`, this is valid. + unsafe impl<T: ZeroableOption> Zeroable for Option<T> {} + + /// Create a new zeroed T. + /// + /// The returned initializer will write `0x00` to every byte of the given `slot`. + #[inline] + pub fn zeroed<T: Zeroable>() -> impl Init<T> { + // SAFETY: Because `T: Zeroable`, all bytes zero is a valid bit pattern for `T` + // and because we write all zeroes, the memory is initialized. + unsafe { + init_from_closure(|slot: *mut T| { + slot.write_bytes(0, 1); + Ok(()) + }) + } + } + + macro_rules! impl_zeroable { + ($($({$($generics:tt)*})? $t:ty, )*) => { + // SAFETY: Safety comments written in the macro invocation. + $(unsafe impl$($($generics)*)? Zeroable for $t {})* + }; + } + + impl_zeroable! { + // SAFETY: All primitives that are allowed to be zero. + bool, + char, + u8, u16, u32, u64, u128, usize, + i8, i16, i32, i64, i128, isize, + f32, f64, + + // Note: do not add uninhabited types (such as `!` or `core::convert::Infallible`) to this list; + // creating an instance of an uninhabited type is immediate undefined behavior. For more on + // uninhabited/empty types, consult The Rustonomicon: + // <https://doc.rust-lang.org/stable/nomicon/exotic-sizes.html#empty-types>. The Rust Reference + // also has information on undefined behavior: + // <https://doc.rust-lang.org/stable/reference/behavior-considered-undefined.html>. + // + // SAFETY: These are inhabited ZSTs; there is nothing to zero and a valid value exists. + {<T: ?Sized>} PhantomData<T>, core::marker::PhantomPinned, (), + + // SAFETY: Type is allowed to take any value, including all zeros. + {<T>} MaybeUninit<T>, + + // SAFETY: `T: Zeroable` and `UnsafeCell` is `repr(transparent)`. + {<T: ?Sized + Zeroable>} UnsafeCell<T>, + - // SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee). ++ // SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee: ++ // https://doc.rust-lang.org/stable/std/option/index.html#representation). + Option<NonZeroU8>, Option<NonZeroU16>, Option<NonZeroU32>, Option<NonZeroU64>, + Option<NonZeroU128>, Option<NonZeroUsize>, + Option<NonZeroI8>, Option<NonZeroI16>, Option<NonZeroI32>, Option<NonZeroI64>, + Option<NonZeroI128>, Option<NonZeroIsize>, + - // SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee). - // - // In this case we are allowed to use `T: ?Sized`, since all zeros is the `None` variant. - {<T: ?Sized>} Option<NonNull<T>>, ++ {<T>} Option<NonNull<T>>, + + // SAFETY: `null` pointer is valid. + // + // We cannot use `T: ?Sized`, since the VTABLE pointer part of fat pointers is not allowed to be + // null. + // + // When `Pointee` gets stabilized, we could use + // `T: ?Sized where <T as Pointee>::Metadata: Zeroable` + {<T>} *mut T, {<T>} *const T, + + // SAFETY: `null` pointer is valid and the metadata part of these fat pointers is allowed to be + // zero. + {<T>} *mut [T], {<T>} *const [T], *mut str, *const str, + + // SAFETY: `T` is `Zeroable`. + {<const N: usize, T: Zeroable>} [T; N], {<T: Zeroable>} Wrapping<T>, + } + + macro_rules! impl_tuple_zeroable { + ($(,)?) => {}; + ($first:ident, $($t:ident),* $(,)?) => { + // SAFETY: All elements are zeroable and padding can be zero. + unsafe impl<$first: Zeroable, $($t: Zeroable),*> Zeroable for ($first, $($t),*) {} + impl_tuple_zeroable!($($t),* ,); + } + } + + impl_tuple_zeroable!(A, B, C, D, E, F, G, H, I, J); diff --cc scripts/generate_rust_analyzer.py index adae71544cbd,54228e87e577..a0e5a0aef444 --- a/scripts/generate_rust_analyzer.py +++ b/scripts/generate_rust_analyzer.py @@@ -97,28 -85,42 +97,43 @@@ def generate_crates(srctree, objtree, s ["core", "compiler_builtins"], ) - append_crate( - "bindings", - srctree / "rust"/ "bindings" / "lib.rs", - ["core"], - cfg=cfg, - ) - crates[-1]["env"]["OBJTREE"] = str(objtree.resolve(True)) - + append_crate( + "pin_init_internal", + srctree / "rust" / "pin-init" / "internal" / "src" / "lib.rs", + [], + cfg=["kernel"], + is_proc_macro=True, + ) + + append_crate( + "pin_init", + srctree / "rust" / "pin-init" / "src" / "lib.rs", + ["core", "pin_init_internal", "macros"], + cfg=["kernel"], + ) + - append_crate( - "kernel", - srctree / "rust" / "kernel" / "lib.rs", - ["core", "macros", "build_error", "bindings", "pin_init"], - cfg=cfg, - ) - crates[-1]["source"] = { - "include_dirs": [ - str(srctree / "rust" / "kernel"), - str(objtree / "rust") - ], - "exclude_dirs": [], - } + def append_crate_with_generated( + display_name, + deps, + ): + append_crate( + display_name, + srctree / "rust"/ display_name / "lib.rs", + deps, + cfg=cfg, + ) + crates[-1]["env"]["OBJTREE"] = str(objtree.resolve(True)) + crates[-1]["source"] = { + "include_dirs": [ + str(srctree / "rust" / display_name), + str(objtree / "rust") + ], + "exclude_dirs": [], + } + + append_crate_with_generated("bindings", ["core"]) + append_crate_with_generated("uapi", ["core"]) - append_crate_with_generated("kernel", ["core", "macros", "build_error", "bindings", "uapi"]) ++ append_crate_with_generated("kernel", ["core", "macros", "build_error", "bindings", "pin_init", "uapi"]) def is_root_crate(build_file, target): try: Then when I merge the rust-hrtimer tree in top of that, the resolution looks like this: 6270ed5f46761dad1d29b06ccb73d86d5c019f3a diff --cc rust/kernel/time/hrtimer.rs index 000000000000,2746e69016aa..d52ce884303d mode 000000,100644..100644 --- a/rust/kernel/time/hrtimer.rs +++ b/rust/kernel/time/hrtimer.rs @@@ -1,0 -1,517 +1,518 @@@ + // SPDX-License-Identifier: GPL-2.0 + + //! Intrusive high resolution timers. + //! + //! Allows running timer callbacks without doing allocations at the time of + //! starting the timer. For now, only one timer per type is allowed. + //! + //! # Vocabulary + //! + //! States: + //! + //! - Stopped: initialized but not started, or cancelled, or not restarted. + //! - Started: initialized and started or restarted. + //! - Running: executing the callback. + //! + //! Operations: + //! + //! * Start + //! * Cancel + //! * Restart + //! + //! Events: + //! + //! * Expire + //! + //! ## State Diagram + //! + //! ```text + //! Return NoRestart + //! +---------------------------------------------------------------------+ + //! | | + //! | | + //! | | + //! | Return Restart | + //! | +------------------------+ | + //! | | | | + //! | | | | + //! v v | | + //! +-----------------+ Start +------------------+ +--------+-----+--+ + //! | +---------------->| | | | + //! Init | | | | Expire | | + //! --------->| Stopped | | Started +---------->| Running | + //! | | Cancel | | | | + //! | |<----------------+ | | | + //! +-----------------+ +---------------+--+ +-----------------+ + //! ^ | + //! | | + //! +---------+ + //! Restart + //! ``` + //! + //! + //! A timer is initialized in the **stopped** state. A stopped timer can be + //! **started** by the `start` operation, with an **expiry** time. After the + //! `start` operation, the timer is in the **started** state. When the timer + //! **expires**, the timer enters the **running** state and the handler is + //! executed. After the handler has returned, the timer may enter the + //! **started* or **stopped** state, depending on the return value of the + //! handler. A timer in the **started** or **running** state may be **canceled** + //! by the `cancel` operation. A timer that is cancelled enters the **stopped** + //! state. + //! + //! A `cancel` or `restart` operation on a timer in the **running** state takes + //! effect after the handler has returned and the timer has transitioned + //! out of the **running** state. + //! + //! A `restart` operation on a timer in the **stopped** state is equivalent to a + //! `start` operation. + + use super::ClockId; -use crate::{init::PinInit, prelude::*, time::Ktime, types::Opaque}; ++use crate::{prelude::*, time::Ktime, types::Opaque}; + use core::marker::PhantomData; ++use pin_init::PinInit; + + /// A timer backed by a C `struct hrtimer`. + /// + /// # Invariants + /// + /// * `self.timer` is initialized by `bindings::hrtimer_setup`. + #[pin_data] + #[repr(C)] + pub struct HrTimer<T> { + #[pin] + timer: Opaque<bindings::hrtimer>, + mode: HrTimerMode, + _t: PhantomData<T>, + } + + // SAFETY: Ownership of an `HrTimer` can be moved to other threads and + // used/dropped from there. + unsafe impl<T> Send for HrTimer<T> {} + + // SAFETY: Timer operations are locked on the C side, so it is safe to operate + // on a timer from multiple threads. + unsafe impl<T> Sync for HrTimer<T> {} + + impl<T> HrTimer<T> { + /// Return an initializer for a new timer instance. + pub fn new(mode: HrTimerMode, clock: ClockId) -> impl PinInit<Self> + where + T: HrTimerCallback, + { + pin_init!(Self { + // INVARIANT: We initialize `timer` with `hrtimer_setup` below. + timer <- Opaque::ffi_init(move |place: *mut bindings::hrtimer| { + // SAFETY: By design of `pin_init!`, `place` is a pointer to a + // live allocation. hrtimer_setup will initialize `place` and + // does not require `place` to be initialized prior to the call. + unsafe { + bindings::hrtimer_setup( + place, + Some(T::Pointer::run), + clock.into_c(), + mode.into_c(), + ); + } + }), + mode: mode, + _t: PhantomData, + }) + } + + /// Get a pointer to the contained `bindings::hrtimer`. + /// + /// This function is useful to get access to the value without creating + /// intermediate references. + /// + /// # Safety + /// + /// `this` must point to a live allocation of at least the size of `Self`. + unsafe fn raw_get(this: *const Self) -> *mut bindings::hrtimer { + // SAFETY: The field projection to `timer` does not go out of bounds, + // because the caller of this function promises that `this` points to an + // allocation of at least the size of `Self`. + unsafe { Opaque::raw_get(core::ptr::addr_of!((*this).timer)) } + } + + /// Cancel an initialized and potentially running timer. + /// + /// If the timer handler is running, this function will block until the + /// handler returns. + /// + /// Note that the timer might be started by a concurrent start operation. If + /// so, the timer might not be in the **stopped** state when this function + /// returns. + /// + /// Users of the `HrTimer` API would not usually call this method directly. + /// Instead they would use the safe [`HrTimerHandle::cancel`] on the handle + /// returned when the timer was started. + /// + /// This function is useful to get access to the value without creating + /// intermediate references. + /// + /// # Safety + /// + /// `this` must point to a valid `Self`. + pub(crate) unsafe fn raw_cancel(this: *const Self) -> bool { + // SAFETY: `this` points to an allocation of at least `HrTimer` size. + let c_timer_ptr = unsafe { HrTimer::raw_get(this) }; + + // If the handler is running, this will wait for the handler to return + // before returning. + // SAFETY: `c_timer_ptr` is initialized and valid. Synchronization is + // handled on the C side. + unsafe { bindings::hrtimer_cancel(c_timer_ptr) != 0 } + } + } + + /// Implemented by pointer types that point to structs that contain a [`HrTimer`]. + /// + /// `Self` must be [`Sync`] because it is passed to timer callbacks in another + /// thread of execution (hard or soft interrupt context). + /// + /// Starting a timer returns a [`HrTimerHandle`] that can be used to manipulate + /// the timer. Note that it is OK to call the start function repeatedly, and + /// that more than one [`HrTimerHandle`] associated with a [`HrTimerPointer`] may + /// exist. A timer can be manipulated through any of the handles, and a handle + /// may represent a cancelled timer. + pub trait HrTimerPointer: Sync + Sized { + /// A handle representing a started or restarted timer. + /// + /// If the timer is running or if the timer callback is executing when the + /// handle is dropped, the drop method of [`HrTimerHandle`] should not return + /// until the timer is stopped and the callback has completed. + /// + /// Note: When implementing this trait, consider that it is not unsafe to + /// leak the handle. + type TimerHandle: HrTimerHandle; + + /// Start the timer with expiry after `expires` time units. If the timer was + /// already running, it is restarted with the new expiry time. + fn start(self, expires: Ktime) -> Self::TimerHandle; + } + + /// Unsafe version of [`HrTimerPointer`] for situations where leaking the + /// [`HrTimerHandle`] returned by `start` would be unsound. This is the case for + /// stack allocated timers. + /// + /// Typical implementers are pinned references such as [`Pin<&T>`]. + /// + /// # Safety + /// + /// Implementers of this trait must ensure that instances of types implementing + /// [`UnsafeHrTimerPointer`] outlives any associated [`HrTimerPointer::TimerHandle`] + /// instances. + pub unsafe trait UnsafeHrTimerPointer: Sync + Sized { + /// A handle representing a running timer. + /// + /// # Safety + /// + /// If the timer is running, or if the timer callback is executing when the + /// handle is dropped, the drop method of [`Self::TimerHandle`] must not return + /// until the timer is stopped and the callback has completed. + type TimerHandle: HrTimerHandle; + + /// Start the timer after `expires` time units. If the timer was already + /// running, it is restarted at the new expiry time. + /// + /// # Safety + /// + /// Caller promises keep the timer structure alive until the timer is dead. + /// Caller can ensure this by not leaking the returned [`Self::TimerHandle`]. + unsafe fn start(self, expires: Ktime) -> Self::TimerHandle; + } + + /// A trait for stack allocated timers. + /// + /// # Safety + /// + /// Implementers must ensure that `start_scoped` does not return until the + /// timer is dead and the timer handler is not running. + pub unsafe trait ScopedHrTimerPointer { + /// Start the timer to run after `expires` time units and immediately + /// after call `f`. When `f` returns, the timer is cancelled. + fn start_scoped<T, F>(self, expires: Ktime, f: F) -> T + where + F: FnOnce() -> T; + } + + // SAFETY: By the safety requirement of [`UnsafeHrTimerPointer`], dropping the + // handle returned by [`UnsafeHrTimerPointer::start`] ensures that the timer is + // killed. + unsafe impl<T> ScopedHrTimerPointer for T + where + T: UnsafeHrTimerPointer, + { + fn start_scoped<U, F>(self, expires: Ktime, f: F) -> U + where + F: FnOnce() -> U, + { + // SAFETY: We drop the timer handle below before returning. + let handle = unsafe { UnsafeHrTimerPointer::start(self, expires) }; + let t = f(); + drop(handle); + t + } + } + + /// Implemented by [`HrTimerPointer`] implementers to give the C timer callback a + /// function to call. + // This is split from `HrTimerPointer` to make it easier to specify trait bounds. + pub trait RawHrTimerCallback { + /// Type of the parameter passed to [`HrTimerCallback::run`]. It may be + /// [`Self`], or a pointer type derived from [`Self`]. + type CallbackTarget<'a>; + + /// Callback to be called from C when timer fires. + /// + /// # Safety + /// + /// Only to be called by C code in the `hrtimer` subsystem. `this` must point + /// to the `bindings::hrtimer` structure that was used to start the timer. + unsafe extern "C" fn run(this: *mut bindings::hrtimer) -> bindings::hrtimer_restart; + } + + /// Implemented by structs that can be the target of a timer callback. + pub trait HrTimerCallback { + /// The type whose [`RawHrTimerCallback::run`] method will be invoked when + /// the timer expires. + type Pointer<'a>: RawHrTimerCallback; + + /// Called by the timer logic when the timer fires. + fn run(this: <Self::Pointer<'_> as RawHrTimerCallback>::CallbackTarget<'_>) -> HrTimerRestart + where + Self: Sized; + } + + /// A handle representing a potentially running timer. + /// + /// More than one handle representing the same timer might exist. + /// + /// # Safety + /// + /// When dropped, the timer represented by this handle must be cancelled, if it + /// is running. If the timer handler is running when the handle is dropped, the + /// drop method must wait for the handler to return before returning. + /// + /// Note: One way to satisfy the safety requirement is to call `Self::cancel` in + /// the drop implementation for `Self.` + pub unsafe trait HrTimerHandle { + /// Cancel the timer. If the timer is in the running state, block till the + /// handler has returned. + /// + /// Note that the timer might be started by a concurrent start operation. If + /// so, the timer might not be in the **stopped** state when this function + /// returns. + fn cancel(&mut self) -> bool; + } + + /// Implemented by structs that contain timer nodes. + /// + /// Clients of the timer API would usually safely implement this trait by using + /// the [`crate::impl_has_hr_timer`] macro. + /// + /// # Safety + /// + /// Implementers of this trait must ensure that the implementer has a + /// [`HrTimer`] field and that all trait methods are implemented according to + /// their documentation. All the methods of this trait must operate on the same + /// field. + pub unsafe trait HasHrTimer<T> { + /// Return a pointer to the [`HrTimer`] within `Self`. + /// + /// This function is useful to get access to the value without creating + /// intermediate references. + /// + /// # Safety + /// + /// `this` must be a valid pointer. + unsafe fn raw_get_timer(this: *const Self) -> *const HrTimer<T>; + + /// Return a pointer to the struct that is containing the [`HrTimer`] pointed + /// to by `ptr`. + /// + /// This function is useful to get access to the value without creating + /// intermediate references. + /// + /// # Safety + /// + /// `ptr` must point to a [`HrTimer<T>`] field in a struct of type `Self`. + unsafe fn timer_container_of(ptr: *mut HrTimer<T>) -> *mut Self + where + Self: Sized; + + /// Get pointer to the contained `bindings::hrtimer` struct. + /// + /// This function is useful to get access to the value without creating + /// intermediate references. + /// + /// # Safety + /// + /// `this` must be a valid pointer. + unsafe fn c_timer_ptr(this: *const Self) -> *const bindings::hrtimer { + // SAFETY: `this` is a valid pointer to a `Self`. + let timer_ptr = unsafe { Self::raw_get_timer(this) }; + + // SAFETY: timer_ptr points to an allocation of at least `HrTimer` size. + unsafe { HrTimer::raw_get(timer_ptr) } + } + + /// Start the timer contained in the `Self` pointed to by `self_ptr`. If + /// it is already running it is removed and inserted. + /// + /// # Safety + /// + /// - `this` must point to a valid `Self`. + /// - Caller must ensure that the pointee of `this` lives until the timer + /// fires or is canceled. + unsafe fn start(this: *const Self, expires: Ktime) { + // SAFETY: By function safety requirement, `this` is a valid `Self`. + unsafe { + bindings::hrtimer_start_range_ns( + Self::c_timer_ptr(this).cast_mut(), + expires.to_ns(), + 0, + (*Self::raw_get_timer(this)).mode.into_c(), + ); + } + } + } + + /// Restart policy for timers. + #[derive(Copy, Clone, PartialEq, Eq, Debug)] + #[repr(u32)] + pub enum HrTimerRestart { + /// Timer should not be restarted. + NoRestart = bindings::hrtimer_restart_HRTIMER_NORESTART, + /// Timer should be restarted. + Restart = bindings::hrtimer_restart_HRTIMER_RESTART, + } + + impl HrTimerRestart { + fn into_c(self) -> bindings::hrtimer_restart { + self as bindings::hrtimer_restart + } + } + + /// Operational mode of [`HrTimer`]. + // NOTE: Some of these have the same encoding on the C side, so we keep + // `repr(Rust)` and convert elsewhere. + #[derive(Clone, Copy, PartialEq, Eq, Debug)] + pub enum HrTimerMode { + /// Timer expires at the given expiration time. + Absolute, + /// Timer expires after the given expiration time interpreted as a duration from now. + Relative, + /// Timer does not move between CPU cores. + Pinned, + /// Timer handler is executed in soft irq context. + Soft, + /// Timer handler is executed in hard irq context. + Hard, + /// Timer expires at the given expiration time. + /// Timer does not move between CPU cores. + AbsolutePinned, + /// Timer expires after the given expiration time interpreted as a duration from now. + /// Timer does not move between CPU cores. + RelativePinned, + /// Timer expires at the given expiration time. + /// Timer handler is executed in soft irq context. + AbsoluteSoft, + /// Timer expires after the given expiration time interpreted as a duration from now. + /// Timer handler is executed in soft irq context. + RelativeSoft, + /// Timer expires at the given expiration time. + /// Timer does not move between CPU cores. + /// Timer handler is executed in soft irq context. + AbsolutePinnedSoft, + /// Timer expires after the given expiration time interpreted as a duration from now. + /// Timer does not move between CPU cores. + /// Timer handler is executed in soft irq context. + RelativePinnedSoft, + /// Timer expires at the given expiration time. + /// Timer handler is executed in hard irq context. + AbsoluteHard, + /// Timer expires after the given expiration time interpreted as a duration from now. + /// Timer handler is executed in hard irq context. + RelativeHard, + /// Timer expires at the given expiration time. + /// Timer does not move between CPU cores. + /// Timer handler is executed in hard irq context. + AbsolutePinnedHard, + /// Timer expires after the given expiration time interpreted as a duration from now. + /// Timer does not move between CPU cores. + /// Timer handler is executed in hard irq context. + RelativePinnedHard, + } + + impl HrTimerMode { + fn into_c(self) -> bindings::hrtimer_mode { + use bindings::*; + match self { + HrTimerMode::Absolute => hrtimer_mode_HRTIMER_MODE_ABS, + HrTimerMode::Relative => hrtimer_mode_HRTIMER_MODE_REL, + HrTimerMode::Pinned => hrtimer_mode_HRTIMER_MODE_PINNED, + HrTimerMode::Soft => hrtimer_mode_HRTIMER_MODE_SOFT, + HrTimerMode::Hard => hrtimer_mode_HRTIMER_MODE_HARD, + HrTimerMode::AbsolutePinned => hrtimer_mode_HRTIMER_MODE_ABS_PINNED, + HrTimerMode::RelativePinned => hrtimer_mode_HRTIMER_MODE_REL_PINNED, + HrTimerMode::AbsoluteSoft => hrtimer_mode_HRTIMER_MODE_ABS_SOFT, + HrTimerMode::RelativeSoft => hrtimer_mode_HRTIMER_MODE_REL_SOFT, + HrTimerMode::AbsolutePinnedSoft => hrtimer_mode_HRTIMER_MODE_ABS_PINNED_SOFT, + HrTimerMode::RelativePinnedSoft => hrtimer_mode_HRTIMER_MODE_REL_PINNED_SOFT, + HrTimerMode::AbsoluteHard => hrtimer_mode_HRTIMER_MODE_ABS_HARD, + HrTimerMode::RelativeHard => hrtimer_mode_HRTIMER_MODE_REL_HARD, + HrTimerMode::AbsolutePinnedHard => hrtimer_mode_HRTIMER_MODE_ABS_PINNED_HARD, + HrTimerMode::RelativePinnedHard => hrtimer_mode_HRTIMER_MODE_REL_PINNED_HARD, + } + } + } + + /// Use to implement the [`HasHrTimer<T>`] trait. + /// + /// See [`module`] documentation for an example. + /// + /// [`module`]: crate::time::hrtimer + #[macro_export] + macro_rules! impl_has_hr_timer { + ( + impl$({$($generics:tt)*})? + HasHrTimer<$timer_type:ty> + for $self:ty + { self.$field:ident } + $($rest:tt)* + ) => { + // SAFETY: This implementation of `raw_get_timer` only compiles if the + // field has the right type. + unsafe impl$(<$($generics)*>)? $crate::time::hrtimer::HasHrTimer<$timer_type> for $self { + + #[inline] + unsafe fn raw_get_timer( + this: *const Self, + ) -> *const $crate::time::hrtimer::HrTimer<$timer_type> { + // SAFETY: The caller promises that the pointer is not dangling. + unsafe { ::core::ptr::addr_of!((*this).$field) } + } + + #[inline] + unsafe fn timer_container_of( + ptr: *mut $crate::time::hrtimer::HrTimer<$timer_type>, + ) -> *mut Self { + // SAFETY: As per the safety requirement of this function, `ptr` + // is pointing inside a `$timer_type`. + unsafe { ::kernel::container_of!(ptr, $timer_type, $field).cast_mut() } + } + } + } + } + + mod arc; + pub use arc::ArcHrTimerHandle; + mod pin; + pub use pin::PinHrTimerHandle; + mod pin_mut; + pub use pin_mut::PinMutHrTimerHandle; + // `box` is a reserved keyword, so prefix with `t` for timer + mod tbox; + pub use tbox::BoxHrTimerHandle; -- Cheers, Stephen Rothwell
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