Struct TaskStateSegmentHeader

#[repr(C, packed(16))]
pub struct TaskStateSegmentHeader {
    pub privileged_stack: [u64; 3],
    pub interrupt_stack: [u64; 7],
    pub io_permission_map_offset: u16,
    /* private fields */
}

Available on x86-64 only.

Stack and I/O permission map pointers that make up the most significant part of a task state segment (TSS).

Since 64-bit mode does not support task switching, the name is a historical artifact, and this does not store any real task state.

Fields

privileged_stack: [u64; 3]

Stack pointers to use when switching to privilege levels 0–2.

interrupt_stack: [u64; 7]

Stack pointers available for use when handling interrupts. The specific entry used is determined by the interrupt_stack_index field of the relevant interrupt gate descriptor.

io_permission_map_offset: u16

Offset from the start of this structure to start of the IOPermissionBitmap.

The I/O permission map ends at the limit of the containing segment, and must be at least two bytes. If this offset is equal to or greater than the limit, then the permission map is empty and all ports are assumed to be zero.

Not modified by the processor on a task switch.

Implementations

impl TaskStateSegmentHeader

pub const fn new() -> Self

Create a header with zero-initialized stack pointers and an io_permission_map_offset that points directly after the header.

Trait Implementations

impl Clone for TaskStateSegmentHeader

fn clone(&self) -> TaskStateSegmentHeader

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TaskStateSegmentHeader

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

Formats the value using the given formatter.

impl Default for TaskStateSegmentHeader

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for TaskStateSegmentHeader

fn eq(&self, other: &TaskStateSegmentHeader) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for TaskStateSegmentHeader

impl Eq for TaskStateSegmentHeader

impl StructuralPartialEq for TaskStateSegmentHeader