Struct TaskContext 

pub struct TaskContext {
    pub ra: usize,
    pub sp: usize,
    pub s: [usize; 10],
    pub fpu: FpuState,
    /* private fields */
}

Available on crate feature context only.

Saved hardware states of a task.

The context usually includes:

• Callee-saved registers
• Stack pointer register
• Thread pointer register (for kernel-space thread-local storage)
• FP/SIMD registers

On context switch, current task saves its context from CPU to memory, and the next task restores its context from memory to CPU.

Fields

ra: usize

Return Address

sp: usize

Stack Pointer

s: [usize; 10]

loongArch need to save 10 static registers from $r22 to $r31

fpu: FpuState

Available on crate feature fp-simd only.

Floating Point Unit states

Implementations

impl TaskContext

pub fn new() -> Self

Creates a new default context for a new task.

pub fn init( &mut self, entry: usize, kstack_top: VirtAddr, kernel_tls: KernelTlsBase, )

Initializes a task context with its entry point, kernel stack, and task-owned kernel TLS base.

pub fn set_task_anchor(&mut self, header: TaskAnchor)

Sets the pinned task-owned runtime task anchor.

pub const fn task_anchor(&self) -> Option<TaskAnchor>

Returns the configured task-owned runtime task anchor.

pub fn clone_user_fp_state_into(&self, child: &mut Self)

Available on crate features fp-simd and uspace only.

Saves the running parent’s hardware FP image into an unpublished child.

The runtime must pin the parent CPU while calling this method. Kernel code uses the soft-float ABI; eager task switching keeps the parent’s user register image live across kernel entry and preemption.

pub fn prepare_switch_to(&mut self, _next_ctx: &Self)

Completes FPU work before current-context publication.

pub unsafe fn switch_to(&mut self, next_ctx: &Self)

Performs only the final GPR/current/TLS transfer.

Safety

Scheduling must be serialized, FPU state prepared, and the next current anchor published. Both contexts and their anchors must remain pinned and alive. IRQs must remain disabled from publication through this call, with no intervening fallible or ownership-sensitive work.

Trait Implementations

impl Debug for TaskContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for TaskContext

fn default() -> TaskContext

Returns the “default value” for a type.