rust: add basic `Task` (313c4281) · Commits · EulixOS / Software / Kernel

rust/bindings/bindings_helper.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -8,6 +8,7 @@

		#include <linux/slab.h>
		#include <linux/refcount.h>
		#include <linux/sched.h>

		/* `bindgen` gets confused at certain things. */
		const gfp_t BINDINGS_GFP_KERNEL = GFP_KERNEL;

rust/helpers.c

+19 −0

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@
		#include <linux/refcount.h>
		#include <linux/mutex.h>
		#include <linux/spinlock.h>
		#include <linux/sched/signal.h>

		__noreturn void rust_helper_BUG(void)
		{
		@@ -60,6 +61,12 @@ void rust_helper_spin_unlock(spinlock_t *lock)
		}
		EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);

		int rust_helper_signal_pending(struct task_struct *t)
		{
		return signal_pending(t);
		}
		EXPORT_SYMBOL_GPL(rust_helper_signal_pending);

		refcount_t rust_helper_REFCOUNT_INIT(int n)
		{
		return (refcount_t)REFCOUNT_INIT(n);
		@@ -96,6 +103,18 @@ long rust_helper_PTR_ERR(__force const void *ptr)
		}
		EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);

		void rust_helper_get_task_struct(struct task_struct *t)
		{
		get_task_struct(t);
		}
		EXPORT_SYMBOL_GPL(rust_helper_get_task_struct);

		void rust_helper_put_task_struct(struct task_struct *t)
		{
		put_task_struct(t);
		}
		EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);

		/*
		* We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type
		* as the Rust `usize` type, so we can use it in contexts where Rust

rust/kernel/lib.rs

+1 −0

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		@@ -44,6 +44,7 @@ mod static_assert;
		pub mod std_vendor;
		pub mod str;
		pub mod sync;
		pub mod task;
		pub mod types;

		#[doc(hidden)]

rust/kernel/task.rs

0 → 100644

+75 −0

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		// SPDX-License-Identifier: GPL-2.0

		//! Tasks (threads and processes).
		//!
		//! C header: [`include/linux/sched.h`](../../../../include/linux/sched.h).

		use crate::{bindings, types::Opaque};
		use core::ptr;

		/// Wraps the kernel's `struct task_struct`.
		///
		/// # Invariants
		///
		/// All instances are valid tasks created by the C portion of the kernel.
		///
		/// Instances of this type are always ref-counted, that is, a call to `get_task_struct` ensures
		/// that the allocation remains valid at least until the matching call to `put_task_struct`.
		#[repr(transparent)]
		pub struct Task(pub(crate) Opaque<bindings::task_struct>);

		// SAFETY: It's OK to access `Task` through references from other threads because we're either
		// accessing properties that don't change (e.g., `pid`, `group_leader`) or that are properly
		// synchronised by C code (e.g., `signal_pending`).
		unsafe impl Sync for Task {}

		/// The type of process identifiers (PIDs).
		type Pid = bindings::pid_t;

		impl Task {
		/// Returns the group leader of the given task.
		pub fn group_leader(&self) -> &Task {
		// SAFETY: By the type invariant, we know that `self.0` is a valid task. Valid tasks always
		// have a valid group_leader.
		let ptr = unsafe { ptr::addr_of!((self.0.get()).group_leader) };

		// SAFETY: The lifetime of the returned task reference is tied to the lifetime of `self`,
		// and given that a task has a reference to its group leader, we know it must be valid for
		// the lifetime of the returned task reference.
		unsafe { &*ptr.cast() }
		}

		/// Returns the PID of the given task.
		pub fn pid(&self) -> Pid {
		// SAFETY: By the type invariant, we know that `self.0` is a valid task. Valid tasks always
		// have a valid pid.
		unsafe { ptr::addr_of!((self.0.get()).pid) }
		}

		/// Determines whether the given task has pending signals.
		pub fn signal_pending(&self) -> bool {
		// SAFETY: By the type invariant, we know that `self.0` is valid.
		unsafe { bindings::signal_pending(self.0.get()) != 0 }
		}

		/// Wakes up the task.
		pub fn wake_up(&self) {
		// SAFETY: By the type invariant, we know that `self.0.get()` is non-null and valid.
		// And `wake_up_process` is safe to be called for any valid task, even if the task is
		// running.
		unsafe { bindings::wake_up_process(self.0.get()) };
		}
		}

		// SAFETY: The type invariants guarantee that `Task` is always ref-counted.
		unsafe impl crate::types::AlwaysRefCounted for Task {
		fn inc_ref(&self) {
		// SAFETY: The existence of a shared reference means that the refcount is nonzero.
		unsafe { bindings::get_task_struct(self.0.get()) };
		}

		unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
		// SAFETY: The safety requirements guarantee that the refcount is nonzero.
		unsafe { bindings::put_task_struct(obj.cast().as_ptr()) }
		}
		}