48 lines
1.4 KiB
Rust
48 lines
1.4 KiB
Rust
use x86_64::VirtAddr;
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use x86_64::structures::tss::TaskStateSegment;
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use x86_64::structures::gdt::{GlobalDescriptorTable, Descriptor, SegmentSelector};
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use lazy_static::lazy_static;
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//double fault interrupt stack table
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pub const DOUBLE_FAULT_IST_INDEX: u16 = 0;
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lazy_static! {
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static ref TSS: TaskStateSegment = {
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let mut tss = TaskStateSegment::new();
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tss.interrupt_stack_table[DOUBLE_FAULT_IST_INDEX as usize] = {
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const STACK_SIZE: usize = 4096; //4k stack
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//this static mut is temporarily the stack until proper allocation can be implemented
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static mut STACK: [u8; STACK_SIZE] = [0; STACK_SIZE];
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let stack_start = VirtAddr::from_ptr(unsafe { &STACK });
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let stack_end = stack_start + STACK_SIZE;
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stack_end
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};
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tss
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};
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}
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struct Selectors {
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code_selector: SegmentSelector,
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data_selector: SegmentSelector,
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}
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lazy_static! {
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static ref GDT: (GlobalDescriptorTable, Selectors) = {
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let mut gdt = GlobalDescriptorTable::new();
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let code_selector = gdt.add_entry(Descriptor::kernel_code_segment());
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let data_selector = gdt.add_entry(Descriptor::tss_segment(&TSS));
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(gdt, Selectors { code_selector, data_selector })
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};
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}
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pub fn init() {
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use x86_64::instructions::segmentation::set_cs;
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use x86_64::instructions::tables::load_tss;
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GDT.0.load();
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unsafe {
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set_cs(GDT.1.code_selector);
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load_tss(GDT.1.data_selector);
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}
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}
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