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//! Provides a type for the task state segment structure.
use crate::VirtAddr;
/// In 64-bit mode the TSS holds information that is not
/// directly related to the task-switch mechanism,
/// but is used for finding kernel level stack
/// if interrupts arrive while in kernel mode.
#[derive(Debug, Clone, Copy)]
#[repr(C, packed)]
pub struct TaskStateSegment {
reserved_1: u32,
/// The full 64-bit canonical forms of the stack pointers (RSP) for privilege levels 0-2.
pub privilege_stack_table: [VirtAddr; 3],
reserved_2: u64,
/// The full 64-bit canonical forms of the interrupt stack table (IST) pointers.
pub interrupt_stack_table: [VirtAddr; 7],
reserved_3: u64,
reserved_4: u16,
/// The 16-bit offset to the I/O permission bit map from the 64-bit TSS base.
pub iomap_base: u16,
}
impl TaskStateSegment {
/// Creates a new TSS with zeroed privilege and interrupt stack table and a zero
/// `iomap_base`.
#[inline]
pub const fn new() -> TaskStateSegment {
TaskStateSegment {
privilege_stack_table: [VirtAddr::zero(); 3],
interrupt_stack_table: [VirtAddr::zero(); 7],
iomap_base: 0,
reserved_1: 0,
reserved_2: 0,
reserved_3: 0,
reserved_4: 0,
}
}
}