Struct tartan_arch::x86::protection::TaskStateSegmentHeader

#[repr(C)]
pub struct TaskStateSegmentHeader {

    pub previous_task: u16,
    pub privileged_stack: [PrivilegedStack; 3],
    pub control_register_3: u32,
    pub instruction_pointer: u32,
    pub flags: u32,
    pub general_a: u32,
    pub general_c: u32,
    pub general_d: u32,
    pub general_b: u32,
    pub stack_pointer: u32,
    pub base_pointer: u32,
    pub source_index: u32,
    pub destination_index: u32,
    pub general_segment_e: Selector,
    pub code_segment: Selector,
    pub stack_segment: Selector,
    pub data_segment: Selector,
    pub general_segment_f: Selector,
    pub general_segment_g: Selector,
    pub local_descriptor_table: Selector,
    pub debug_trap: bool,
    pub io_permission_map_offset: u16,
    pub shadow_stack_pointer: u32,
    /* private fields */
}

Available on x86 only.

Saved task state that makes up the most significant part of a task state segment (TSS).

Some of the fields of this header are automatically saved by the processor when switching tasks. Refer to each field’s documentation.

This header can be followed by OS-specific data and/or the TaskStateSegmentBitmaps. The location of the latter is determined by io_permission_map_offset.

Fields

previous_task: u16

Segment selector saved by the processor referencing the task that was running before this task was activated.

If FlagRegister::nested_task is set, then this task will be resumed by the IRET instruction.

privileged_stack: [PrivilegedStack; 3]

Stack pointer and segment for privilege levels 0–2.

Not modified by the processor on a task switch.

control_register_3: u32

Page table pointer from ControlRegister3.

Not modified by the processor on a task switch.

instruction_pointer: u32

EIP value saved by the processor.

flags: u32

EFLAGS value saved by the processor.

general_a: u32

EAX value saved by the processor.

general_c: u32

ECX value saved by the processor.

general_d: u32

EDX value saved by the processor.

general_b: u32

EBX value saved by the processor.

stack_pointer: u32

SP value saved by the processor for privilege level 3.

base_pointer: u32

EBP value saved by the processor.

source_index: u32

ESI value saved by the processor.

destination_index: u32

EDI value saved by the processor.

general_segment_e: Selector

ES value saved by the processor.

code_segment: Selector

CS value saved by the processor.

stack_segment: Selector

SS value saved by the processor for privilege level 3.

data_segment: Selector

DS value saved by the processor.

general_segment_f: Selector

FS value saved by the processor.

general_segment_g: Selector

GS value saved by the processor.

local_descriptor_table: Selector

LocalDescriptorTableRegister value to load when executing this task.

Not modified by the processor on a task switch.

debug_trap: bool

Indicates that a debug exception should be raised when this task is activated.

Not modified by the processor on a task switch.

io_permission_map_offset: u16

Offset from the start of this structure to start of the IOPermissionBitmap, and to the end of the interrupt_redirect bitmap.

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.

The interrupt redirect bitmap begins at this offset minus 32.

Not modified by the processor on a task switch.

shadow_stack_pointer: u32

Pointer to the shadow stack.

Not modified by the processor on a task switch.

Implementations

impl TaskStateSegmentHeader

pub const fn new() -> Self

Create a new zero-initialized 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 PartialEq for TaskStateSegmentHeader

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

This method tests for self and other values to be equal, and is used by ==.

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

This method 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