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96 lines
3.1 KiB
96 lines
3.1 KiB
use x86_64::VirtualAddress;
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use x86_64::structures::idt::Idt;
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use x86_64::structures::tss::TaskStateSegment;
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use memory::MemoryController;
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use spin::Once;
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mod gdt;
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mod irq;
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lazy_static! {
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static ref IDT: Idt = {
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use self::irq::*;
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let mut idt = Idt::new();
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idt.breakpoint.set_handler_fn(breakpoint_handler);
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idt.page_fault.set_handler_fn(page_fault_handler);
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unsafe {
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idt.double_fault.set_handler_fn(double_fault_handler)
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.set_stack_index(DOUBLE_FAULT_IST_INDEX as u16);
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}
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idt
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};
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}
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// Copied from xv6 x86_64
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const GNULL: gdt::Descriptor = gdt::Descriptor::UserSegment(0);
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const KCODE: gdt::Descriptor = gdt::Descriptor::UserSegment(0x0020980000000000); // EXECUTABLE | USER_SEGMENT | PRESENT | LONG_MODE
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const UCODE: gdt::Descriptor = gdt::Descriptor::UserSegment(0x0020F80000000000); // EXECUTABLE | USER_SEGMENT | USER_MODE | PRESENT | LONG_MODE
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const KDATA: gdt::Descriptor = gdt::Descriptor::UserSegment(0x0000920000000000); // DATA_WRITABLE | USER_SEGMENT | PRESENT
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const UDATA: gdt::Descriptor = gdt::Descriptor::UserSegment(0x0000F20000000000); // DATA_WRITABLE | USER_SEGMENT | USER_MODE | PRESENT
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static TSS: Once<TaskStateSegment> = Once::new();
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static GDT: Once<gdt::Gdt> = Once::new();
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const DOUBLE_FAULT_IST_INDEX: usize = 0;
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pub fn init(memory_controller: &mut MemoryController) {
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test::print_flags();
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use x86_64::structures::gdt::SegmentSelector;
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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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let double_fault_stack = memory_controller.alloc_stack(1)
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.expect("could not allocate double fault stack");
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let tss = TSS.call_once(|| {
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let mut tss = TaskStateSegment::new();
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tss.interrupt_stack_table[DOUBLE_FAULT_IST_INDEX] = VirtualAddress(
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double_fault_stack.top());
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tss
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});
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let mut code_selector = SegmentSelector(0);
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let mut tss_selector = SegmentSelector(0);
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let gdt = GDT.call_once(|| {
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let mut gdt = gdt::Gdt::new();
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gdt.add_entry(GNULL);
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code_selector =
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gdt.add_entry(KCODE);
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gdt.add_entry(UCODE);
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gdt.add_entry(KDATA);
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gdt.add_entry(UDATA);
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tss_selector = gdt.add_entry(gdt::Descriptor::tss_segment(&tss));
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gdt
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});
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gdt.load();
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unsafe {
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// reload code segment register
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set_cs(code_selector);
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// load TSS
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load_tss(tss_selector);
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}
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IDT.load();
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}
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pub mod test
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{
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pub fn print_flags() {
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use super::gdt::*;
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// The following 4 GDT entries were copied from xv6 x86_64
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let list: [(&str, Descriptor); 4] = [
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("KCODE", super::KCODE), // Code, DPL=0, R/X
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("UCODE", super::UCODE), // Code, DPL=3, R/X
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("KDATA", super::KDATA), // Data, DPL=0, W
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("UDATA", super::UDATA), // Data, DPL=3, W
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];
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// Let's see what that means
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println!("GDT Segments from xv6 x86_64:");
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for (name, desc) in list.iter() {
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println!(" {}: {:?}", name, desc);
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}
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}
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} |