zircon/kernel/object/thread_dispatcher.rs - fuchsia - Git at Google

 // Copyright 2026 The Fuchsia Authors
 //
 // Use of this source code is governed by a MIT-style
 // license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT

 use super::handle::KernelHandle;
 use super::process_dispatcher::ProcessDispatcher;
 use super::thread_dispatcher_ffi::{
     cpp_sys_thread_legacy_yield, cpp_sys_thread_raise_exception, cpp_thread_dispatcher_create,
     cpp_thread_dispatcher_exit_current, cpp_thread_dispatcher_get_info_for_userspace,
     cpp_thread_dispatcher_get_runtime_stats, cpp_thread_dispatcher_get_stats_for_userspace,
     cpp_thread_dispatcher_initialize, cpp_thread_dispatcher_is_current, cpp_thread_dispatcher_kill,
     cpp_thread_dispatcher_kill_current, cpp_thread_dispatcher_read_state,
     cpp_thread_dispatcher_restricted_kick, cpp_thread_dispatcher_resume,
     cpp_thread_dispatcher_set_base_profile, cpp_thread_dispatcher_set_soft_affinity,
     cpp_thread_dispatcher_start, cpp_thread_dispatcher_suspend, cpp_thread_dispatcher_write_state,
 };
 use core::mem::MaybeUninit;
 use object_constants_rs as object_constants;
 use zx_status::Status;
 use zx_types::{
     zx_exception_context_t, zx_excp_type_t, zx_info_task_runtime_t, zx_info_thread_stats_t,
     zx_info_thread_t, zx_rights_t, zx_vaddr_t,
 };

 pub use crate::kernel::types::cpu_mask_t;

 /// Opaque byte container matching C++ `SchedulerState::BaseProfile`.
 #[repr(C, align(8))]
 pub struct SchedulerStateBaseProfile(
     pub zr::OpaqueBytes<{ object_constants::kSchedulerStateBaseProfileSize }>,
 );

 zr::static_assert_size_and_align!(
     SchedulerStateBaseProfile,
     object_constants::kSchedulerStateBaseProfileSize,
     object_constants::kSchedulerStateBaseProfileAlign,
 );

 impl SchedulerStateBaseProfile {
     /// Returns a raw pointer to the underlying byte storage.
     pub fn get(&self) -> *mut [u8; object_constants::kSchedulerStateBaseProfileSize] {
         self.0.get()
     }
 }

 crate::object::dispatcher::impl_dispatcher_facade!(
     pub struct ThreadDispatcher,
     zx_types::ZX_OBJ_TYPE_THREAD
 );

 zr::static_assert!(core::mem::size_of::<ThreadDispatcher>() == 0);

 impl ThreadDispatcher {
     /// Default rights assigned to a newly created ThreadDispatcher handle.
     pub const DEFAULT_RIGHTS: zx_rights_t = zx_types::ZX_RIGHT_TRANSFER
         | zx_types::ZX_RIGHT_DUPLICATE
         | zx_types::ZX_RIGHT_WAIT
         | zx_types::ZX_RIGHT_INSPECT
         | zx_types::ZX_RIGHT_READ
         | zx_types::ZX_RIGHT_WRITE
         | zx_types::ZX_RIGHT_GET_PROPERTY
         | zx_types::ZX_RIGHT_SET_PROPERTY
         | zx_types::ZX_RIGHT_DESTROY
         | zx_types::ZX_RIGHT_SIGNAL
         | zx_types::ZX_RIGHT_MANAGE_THREAD;

     /// Returns default rights for a thread handle.
     pub const fn default_rights() -> zx_rights_t {
         Self::DEFAULT_RIGHTS
     }

     /// Creates a new child `ThreadDispatcher` under the given parent process.
     pub fn create(
         process: fbl::RefPtr<ProcessDispatcher>,
         flags: u32,
         name: &[u8],
     ) -> Result<(KernelHandle<Self>, zx_rights_t), Status> {
         let mut handle = MaybeUninit::<KernelHandle<Self>>::uninit();
         let mut rights = MaybeUninit::<zx_rights_t>::uninit();
         let process_raw = fbl::RefPtr::into_raw(process) as *mut _;
         // SAFETY: `process_raw` is a valid pointer carrying an acquired refcount.
         let status = unsafe {
             cpp_thread_dispatcher_create(
                 process_raw,
                 flags,
                 name.as_ptr() as *const _,
                 name.len(),
                 handle.as_mut_ptr(),
                 rights.as_mut_ptr(),
             )
         };
         Status::ok(status)?;
         // SAFETY: `cpp_thread_dispatcher_create` initialized handle and rights on success.
         unsafe { Ok((handle.assume_init(), rights.assume_init())) }
     }

     /// Initializes a newly created `ThreadDispatcher`.
     pub fn initialize(&self) -> Result<(), Status> {
         // SAFETY: `self` is a valid `ThreadDispatcher` reference.
         let status = unsafe { cpp_thread_dispatcher_initialize(self as *const _ as *mut _) };
         Status::ok(status)
     }

     /// Starts execution of this thread.
     #[allow(clippy::too_many_arguments)]
     pub fn start(
         &self,
         entry: zx_vaddr_t,
         stack: zx_vaddr_t,
         arg1: u64,
         arg2: u64,
         tp: u64,
         abi_reg: u64,
         ensure_initial_thread: bool,
     ) -> Result<(), Status> {
         // SAFETY: `self` is a valid `ThreadDispatcher` reference.
         let status = unsafe {
             cpp_thread_dispatcher_start(
                 self as *const _ as *mut _,
                 entry,
                 stack,
                 arg1,
                 arg2,
                 tp,
                 abi_reg,
                 ensure_initial_thread,
             )
         };
         Status::ok(status)
     }

     /// Terminates the current thread. Does not return.
     pub fn exit_current() -> ! {
         // SAFETY: Terminates the current execution thread cleanly.
         unsafe {
             cpp_thread_dispatcher_exit_current();
         }
         unreachable!()
     }

     /// Marks the current thread for termination.
     pub fn kill_current() {
         // SAFETY: Sets the current thread's state to dying.
         unsafe {
             cpp_thread_dispatcher_kill_current();
         }
     }

     /// Kills this thread.
     pub fn kill(&self) {
         // SAFETY: `self` is a valid `ThreadDispatcher` reference.
         unsafe { cpp_thread_dispatcher_kill(self as *const _ as *mut _) }
     }

     /// Returns whether this `ThreadDispatcher` is the current thread.
     pub fn is_current(&self) -> bool {
         // SAFETY: `self` is a valid `ThreadDispatcher` reference.
         unsafe { cpp_thread_dispatcher_is_current(self as *const _) }
     }

     /// Suspends execution of this thread.
     pub fn suspend(&self) -> Result<(), Status> {
         // SAFETY: `self` is a valid `ThreadDispatcher` reference.
         let status = unsafe { cpp_thread_dispatcher_suspend(self as *const _ as *mut _) };
         Status::ok(status)
     }

     /// Resumes execution of this thread.
     pub fn resume(&self) {
         // SAFETY: `self` is a valid `ThreadDispatcher` reference.
         unsafe { cpp_thread_dispatcher_resume(self as *const _ as *mut _) }
     }

     /// Kicks this thread out of restricted mode.
     pub fn restricted_kick(&self) -> Result<(), Status> {
         // SAFETY: `self` is a valid `ThreadDispatcher` reference.
         let status = unsafe { cpp_thread_dispatcher_restricted_kick(self as *const _ as *mut _) };
         Status::ok(status)
     }

     /// Reads architectural state from this thread into `buffer`.
     pub fn read_state(
         &self,
         state_kind: u32,
         buffer: *mut core::ffi::c_void,
         buffer_size: usize,
     ) -> Result<(), Status> {
         // SAFETY: `self` is a valid `ThreadDispatcher` reference.
         let status = unsafe {
             cpp_thread_dispatcher_read_state(
                 self as *const _ as *mut _,
                 state_kind,
                 buffer,
                 buffer_size,
             )
         };
         Status::ok(status)
     }

     /// Writes architectural state to this thread from `buffer`.
     pub fn write_state(
         &self,
         state_kind: u32,
         buffer: *const core::ffi::c_void,
         buffer_size: usize,
     ) -> Result<(), Status> {
         // SAFETY: `self` is a valid `ThreadDispatcher` reference.
         let status = unsafe {
             cpp_thread_dispatcher_write_state(
                 self as *const _ as *mut _,
                 state_kind,
                 buffer,
                 buffer_size,
             )
         };
         Status::ok(status)
     }

     /// Sets the base profile for this thread.
     pub fn set_base_profile(&self, profile: &SchedulerStateBaseProfile) -> Result<(), Status> {
         // SAFETY: `self` is a valid `ThreadDispatcher` reference and `profile` points to
         // an opaque `SchedulerState::BaseProfile`.
         let status = unsafe {
             cpp_thread_dispatcher_set_base_profile(
                 self as *const _ as *mut _,
                 profile.get() as *const _,
             )
         };
         Status::ok(status)
     }

     /// Sets soft CPU affinity for this thread.
     pub fn set_soft_affinity(&self, mask: cpu_mask_t) -> Result<(), Status> {
         // SAFETY: `self` is a valid `ThreadDispatcher` reference.
         let status =
             unsafe { cpp_thread_dispatcher_set_soft_affinity(self as *const _ as *mut _, mask) };
         Status::ok(status)
     }

     /// Returns thread info for userspace.
     pub fn get_info_for_userspace(&self) -> zx_info_thread_t {
         let mut info = MaybeUninit::<zx_info_thread_t>::uninit();
         // SAFETY: `self` is valid and `info` points to uninitialized stack memory.
         unsafe {
             cpp_thread_dispatcher_get_info_for_userspace(self as *const _, info.as_mut_ptr());
             info.assume_init()
         }
     }

     /// Returns thread CPU stats for userspace.
     pub fn get_stats_for_userspace(&self) -> Result<zx_info_thread_stats_t, Status> {
         let mut info = MaybeUninit::<zx_info_thread_stats_t>::uninit();
         // SAFETY: `self` is valid and `info` points to uninitialized stack memory.
         let status = unsafe {
             cpp_thread_dispatcher_get_stats_for_userspace(
                 self as *const _ as *mut _,
                 info.as_mut_ptr(),
             )
         };
         Status::ok(status)?;
         // SAFETY: `cpp_thread_dispatcher_get_stats_for_userspace` initialized `info` on success.
         unsafe { Ok(info.assume_init()) }
     }

     /// Returns thread task runtime stats.
     pub fn get_runtime_stats(&self) -> zx_info_task_runtime_t {
         let mut info = MaybeUninit::<zx_info_task_runtime_t>::uninit();
         // SAFETY: `self` is valid and `info` points to uninitialized stack memory.
         unsafe {
             cpp_thread_dispatcher_get_runtime_stats(self as *const _, info.as_mut_ptr());
             info.assume_init()
         }
     }

     /// Raises a user exception for the job debugger.
     pub fn raise_user_exception(
         options: u32,
         exception_type: zx_excp_type_t,
         user_context: &zx_exception_context_t,
     ) -> Result<(), Status> {
         // SAFETY: `user_context` is a valid reference.
         let status =
             unsafe { cpp_sys_thread_raise_exception(options, exception_type, user_context) };
         Status::ok(status)
     }

     /// Yields execution of the current thread.
     pub fn legacy_yield(options: u32) -> Result<(), Status> {
         // SAFETY: `cpp_sys_thread_legacy_yield` yields the current thread if options is 0.
         let status = unsafe { cpp_sys_thread_legacy_yield(options) };
         Status::ok(status)
     }
 }

 /// The reason a thread is currently blocked, matching C++ `ThreadDispatcher::Blocked`.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 #[repr(transparent)]
 pub struct Blocked(pub u32);

 impl Blocked {
     pub const NONE: Self = Self(0);
     pub const EXCEPTION: Self = Self(1);
     pub const SLEEPING: Self = Self(2);
     pub const FUTEX: Self = Self(3);
     pub const PORT: Self = Self(4);
     pub const CHANNEL: Self = Self(5);
     pub const WAIT_ONE: Self = Self(6);
     pub const WAIT_MANY: Self = Self(7);
     pub const INTERRUPT: Self = Self(8);
     pub const PAGER: Self = Self(9);
 }

 /// RAII helper that sets the current thread's `blocked_reason_` and restores it on drop.
 pub struct AutoBlocked {
     prev_reason: Blocked,
 }

 impl AutoBlocked {
     /// Sets the blocked reason on the current thread.
     pub fn new(reason: Blocked) -> Self {
         // SAFETY: `cpp_thread_dispatcher_set_blocked_reason` transitions the current thread's
         // blocked state on the current CPU and returns the previous blocked reason.
         let prev_reason = unsafe {
             super::thread_dispatcher_ffi::cpp_thread_dispatcher_set_blocked_reason(reason)
         };
         Self { prev_reason }
     }
 }

 impl Drop for AutoBlocked {
     fn drop(&mut self) {
         // SAFETY: Restoring the previous blocked reason on the current thread upon exiting
         // the blocking scope is always safe and restores previous thread state.
         unsafe {
             super::thread_dispatcher_ffi::cpp_thread_dispatcher_set_blocked_reason(
                 self.prev_reason,
             );
         }
     }
 }

 zr::static_assert!(core::mem::size_of::<Blocked>() == 4);
 zr::static_assert!(core::mem::align_of::<Blocked>() == 4);
	// Copyright 2026 The Fuchsia Authors
	//
	// Use of this source code is governed by a MIT-style
	// license that can be found in the LICENSE file or at
	// https://opensource.org/licenses/MIT

	use super::handle::KernelHandle;
	use super::process_dispatcher::ProcessDispatcher;
	use super::thread_dispatcher_ffi::{
	cpp_sys_thread_legacy_yield, cpp_sys_thread_raise_exception, cpp_thread_dispatcher_create,
	cpp_thread_dispatcher_exit_current, cpp_thread_dispatcher_get_info_for_userspace,
	cpp_thread_dispatcher_get_runtime_stats, cpp_thread_dispatcher_get_stats_for_userspace,
	cpp_thread_dispatcher_initialize, cpp_thread_dispatcher_is_current, cpp_thread_dispatcher_kill,
	cpp_thread_dispatcher_kill_current, cpp_thread_dispatcher_read_state,
	cpp_thread_dispatcher_restricted_kick, cpp_thread_dispatcher_resume,
	cpp_thread_dispatcher_set_base_profile, cpp_thread_dispatcher_set_soft_affinity,
	cpp_thread_dispatcher_start, cpp_thread_dispatcher_suspend, cpp_thread_dispatcher_write_state,
	};
	use core::mem::MaybeUninit;
	use object_constants_rs as object_constants;
	use zx_status::Status;
	use zx_types::{
	zx_exception_context_t, zx_excp_type_t, zx_info_task_runtime_t, zx_info_thread_stats_t,
	zx_info_thread_t, zx_rights_t, zx_vaddr_t,
	};

	pub use crate::kernel::types::cpu_mask_t;

	/// Opaque byte container matching C++ `SchedulerState::BaseProfile`.
	#[repr(C, align(8))]
	pub struct SchedulerStateBaseProfile(
	pub zr::OpaqueBytes<{ object_constants::kSchedulerStateBaseProfileSize }>,
	);

	zr::static_assert_size_and_align!(
	SchedulerStateBaseProfile,
	object_constants::kSchedulerStateBaseProfileSize,
	object_constants::kSchedulerStateBaseProfileAlign,
	);

	impl SchedulerStateBaseProfile {
	/// Returns a raw pointer to the underlying byte storage.
	pub fn get(&self) -> *mut [u8; object_constants::kSchedulerStateBaseProfileSize] {
	self.0.get()
	}
	}

	crate::object::dispatcher::impl_dispatcher_facade!(
	pub struct ThreadDispatcher,
	zx_types::ZX_OBJ_TYPE_THREAD
	);

	zr::static_assert!(core::mem::size_of::<ThreadDispatcher>() == 0);

	impl ThreadDispatcher {
	/// Default rights assigned to a newly created ThreadDispatcher handle.
	pub const DEFAULT_RIGHTS: zx_rights_t = zx_types::ZX_RIGHT_TRANSFER
	\| zx_types::ZX_RIGHT_DUPLICATE
	\| zx_types::ZX_RIGHT_WAIT
	\| zx_types::ZX_RIGHT_INSPECT
	\| zx_types::ZX_RIGHT_READ
	\| zx_types::ZX_RIGHT_WRITE
	\| zx_types::ZX_RIGHT_GET_PROPERTY
	\| zx_types::ZX_RIGHT_SET_PROPERTY
	\| zx_types::ZX_RIGHT_DESTROY
	\| zx_types::ZX_RIGHT_SIGNAL
	\| zx_types::ZX_RIGHT_MANAGE_THREAD;

	/// Returns default rights for a thread handle.
	pub const fn default_rights() -> zx_rights_t {
	Self::DEFAULT_RIGHTS
	}

	/// Creates a new child `ThreadDispatcher` under the given parent process.
	pub fn create(
	process: fbl::RefPtr<ProcessDispatcher>,
	flags: u32,
	name: &[u8],
	) -> Result<(KernelHandle<Self>, zx_rights_t), Status> {
	let mut handle = MaybeUninit::<KernelHandle<Self>>::uninit();
	let mut rights = MaybeUninit::<zx_rights_t>::uninit();
	let process_raw = fbl::RefPtr::into_raw(process) as *mut _;
	// SAFETY: `process_raw` is a valid pointer carrying an acquired refcount.
	let status = unsafe {
	cpp_thread_dispatcher_create(
	process_raw,
	flags,
	name.as_ptr() as *const _,
	name.len(),
	handle.as_mut_ptr(),
	rights.as_mut_ptr(),
	)
	};
	Status::ok(status)?;
	// SAFETY: `cpp_thread_dispatcher_create` initialized handle and rights on success.
	unsafe { Ok((handle.assume_init(), rights.assume_init())) }
	}

	/// Initializes a newly created `ThreadDispatcher`.
	pub fn initialize(&self) -> Result<(), Status> {
	// SAFETY: `self` is a valid `ThreadDispatcher` reference.
	let status = unsafe { cpp_thread_dispatcher_initialize(self as const _ as mut _) };
	Status::ok(status)
	}

	/// Starts execution of this thread.
	#[allow(clippy::too_many_arguments)]
	pub fn start(
	&self,
	entry: zx_vaddr_t,
	stack: zx_vaddr_t,
	arg1: u64,
	arg2: u64,
	tp: u64,
	abi_reg: u64,
	ensure_initial_thread: bool,
	) -> Result<(), Status> {
	// SAFETY: `self` is a valid `ThreadDispatcher` reference.
	let status = unsafe {
	cpp_thread_dispatcher_start(
	self as const _ as mut _,
	entry,
	stack,
	arg1,
	arg2,
	tp,
	abi_reg,
	ensure_initial_thread,
	)
	};
	Status::ok(status)
	}

	/// Terminates the current thread. Does not return.
	pub fn exit_current() -> ! {
	// SAFETY: Terminates the current execution thread cleanly.
	unsafe {
	cpp_thread_dispatcher_exit_current();
	}
	unreachable!()
	}

	/// Marks the current thread for termination.
	pub fn kill_current() {
	// SAFETY: Sets the current thread's state to dying.
	unsafe {
	cpp_thread_dispatcher_kill_current();
	}
	}

	/// Kills this thread.
	pub fn kill(&self) {
	// SAFETY: `self` is a valid `ThreadDispatcher` reference.
	unsafe { cpp_thread_dispatcher_kill(self as const _ as mut _) }
	}

	/// Returns whether this `ThreadDispatcher` is the current thread.
	pub fn is_current(&self) -> bool {
	// SAFETY: `self` is a valid `ThreadDispatcher` reference.
	unsafe { cpp_thread_dispatcher_is_current(self as *const _) }
	}

	/// Suspends execution of this thread.
	pub fn suspend(&self) -> Result<(), Status> {
	// SAFETY: `self` is a valid `ThreadDispatcher` reference.
	let status = unsafe { cpp_thread_dispatcher_suspend(self as const _ as mut _) };
	Status::ok(status)
	}

	/// Resumes execution of this thread.
	pub fn resume(&self) {
	// SAFETY: `self` is a valid `ThreadDispatcher` reference.
	unsafe { cpp_thread_dispatcher_resume(self as const _ as mut _) }
	}

	/// Kicks this thread out of restricted mode.
	pub fn restricted_kick(&self) -> Result<(), Status> {
	// SAFETY: `self` is a valid `ThreadDispatcher` reference.
	let status = unsafe { cpp_thread_dispatcher_restricted_kick(self as const _ as mut _) };
	Status::ok(status)
	}

	/// Reads architectural state from this thread into `buffer`.
	pub fn read_state(
	&self,
	state_kind: u32,
	buffer: *mut core::ffi::c_void,
	buffer_size: usize,
	) -> Result<(), Status> {
	// SAFETY: `self` is a valid `ThreadDispatcher` reference.
	let status = unsafe {
	cpp_thread_dispatcher_read_state(
	self as const _ as mut _,
	state_kind,
	buffer,
	buffer_size,
	)
	};
	Status::ok(status)
	}

	/// Writes architectural state to this thread from `buffer`.
	pub fn write_state(
	&self,
	state_kind: u32,
	buffer: *const core::ffi::c_void,
	buffer_size: usize,
	) -> Result<(), Status> {
	// SAFETY: `self` is a valid `ThreadDispatcher` reference.
	let status = unsafe {
	cpp_thread_dispatcher_write_state(
	self as const _ as mut _,
	state_kind,
	buffer,
	buffer_size,
	)
	};
	Status::ok(status)
	}

	/// Sets the base profile for this thread.
	pub fn set_base_profile(&self, profile: &SchedulerStateBaseProfile) -> Result<(), Status> {
	// SAFETY: `self` is a valid `ThreadDispatcher` reference and `profile` points to
	// an opaque `SchedulerState::BaseProfile`.
	let status = unsafe {
	cpp_thread_dispatcher_set_base_profile(
	self as const _ as mut _,
	profile.get() as *const _,
	)
	};
	Status::ok(status)
	}

	/// Sets soft CPU affinity for this thread.
	pub fn set_soft_affinity(&self, mask: cpu_mask_t) -> Result<(), Status> {
	// SAFETY: `self` is a valid `ThreadDispatcher` reference.
	let status =
	unsafe { cpp_thread_dispatcher_set_soft_affinity(self as const _ as mut _, mask) };
	Status::ok(status)
	}

	/// Returns thread info for userspace.
	pub fn get_info_for_userspace(&self) -> zx_info_thread_t {
	let mut info = MaybeUninit::<zx_info_thread_t>::uninit();
	// SAFETY: `self` is valid and `info` points to uninitialized stack memory.
	unsafe {
	cpp_thread_dispatcher_get_info_for_userspace(self as *const _, info.as_mut_ptr());
	info.assume_init()
	}
	}

	/// Returns thread CPU stats for userspace.
	pub fn get_stats_for_userspace(&self) -> Result<zx_info_thread_stats_t, Status> {
	let mut info = MaybeUninit::<zx_info_thread_stats_t>::uninit();
	// SAFETY: `self` is valid and `info` points to uninitialized stack memory.
	let status = unsafe {
	cpp_thread_dispatcher_get_stats_for_userspace(
	self as const _ as mut _,
	info.as_mut_ptr(),
	)
	};
	Status::ok(status)?;
	// SAFETY: `cpp_thread_dispatcher_get_stats_for_userspace` initialized `info` on success.
	unsafe { Ok(info.assume_init()) }
	}

	/// Returns thread task runtime stats.
	pub fn get_runtime_stats(&self) -> zx_info_task_runtime_t {
	let mut info = MaybeUninit::<zx_info_task_runtime_t>::uninit();
	// SAFETY: `self` is valid and `info` points to uninitialized stack memory.
	unsafe {
	cpp_thread_dispatcher_get_runtime_stats(self as *const _, info.as_mut_ptr());
	info.assume_init()
	}
	}

	/// Raises a user exception for the job debugger.
	pub fn raise_user_exception(
	options: u32,
	exception_type: zx_excp_type_t,
	user_context: &zx_exception_context_t,
	) -> Result<(), Status> {
	// SAFETY: `user_context` is a valid reference.
	let status =
	unsafe { cpp_sys_thread_raise_exception(options, exception_type, user_context) };
	Status::ok(status)
	}

	/// Yields execution of the current thread.
	pub fn legacy_yield(options: u32) -> Result<(), Status> {
	// SAFETY: `cpp_sys_thread_legacy_yield` yields the current thread if options is 0.
	let status = unsafe { cpp_sys_thread_legacy_yield(options) };
	Status::ok(status)
	}
	}

	/// The reason a thread is currently blocked, matching C++ `ThreadDispatcher::Blocked`.
	#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
	#[repr(transparent)]
	pub struct Blocked(pub u32);

	impl Blocked {
	pub const NONE: Self = Self(0);
	pub const EXCEPTION: Self = Self(1);
	pub const SLEEPING: Self = Self(2);
	pub const FUTEX: Self = Self(3);
	pub const PORT: Self = Self(4);
	pub const CHANNEL: Self = Self(5);
	pub const WAIT_ONE: Self = Self(6);
	pub const WAIT_MANY: Self = Self(7);
	pub const INTERRUPT: Self = Self(8);
	pub const PAGER: Self = Self(9);
	}

	/// RAII helper that sets the current thread's `blocked_reason_` and restores it on drop.
	pub struct AutoBlocked {
	prev_reason: Blocked,
	}

	impl AutoBlocked {
	/// Sets the blocked reason on the current thread.
	pub fn new(reason: Blocked) -> Self {
	// SAFETY: `cpp_thread_dispatcher_set_blocked_reason` transitions the current thread's
	// blocked state on the current CPU and returns the previous blocked reason.
	let prev_reason = unsafe {
	super::thread_dispatcher_ffi::cpp_thread_dispatcher_set_blocked_reason(reason)
	};
	Self { prev_reason }
	}
	}

	impl Drop for AutoBlocked {
	fn drop(&mut self) {
	// SAFETY: Restoring the previous blocked reason on the current thread upon exiting
	// the blocking scope is always safe and restores previous thread state.
	unsafe {
	super::thread_dispatcher_ffi::cpp_thread_dispatcher_set_blocked_reason(
	self.prev_reason,
	);
	}
	}
	}

	zr::static_assert!(core::mem::size_of::<Blocked>() == 4);
	zr::static_assert!(core::mem::align_of::<Blocked>() == 4);