Some code?

src/gdt.rs

@@ -0,0 +1,33 @@
+use lazy_static::lazy_static;
+use x86_64::structures::gdt::{Descriptor, GlobalDescriptorTable, SegmentSelector};
+use x86_64::structures::tss::TaskStateSegment;
+use x86_64::VirtAddr;
+
+pub const DOUBLE_FAULT_IST_INDEX: u16 = 0;
+
+lazy_static! {
+    static ref TSS: TaskStateSegment = {
+        let mut tss = TaskStateSegment::new();
+        tss.interrupt_stack_table[DOUBLE_FAULT_IST_INDEX as usize] = {
+            const STACK_SIZE: usize = 4096 * 5;
+            static mut STACK: [u8; STACK_SIZE] = [0; STACK_SIZE];
+            let stack_start = VirtAddr::from_ptr(unsafe { &STACK });
+            let stack_end = stack_start + STACK_SIZE;
+            stack_end
+        };
+        tss
+    };
+}
+
+lazy_static! {
+    static ref GDT: GlobalDescriptorTable = {
+        let mut gdt = GlobalDescriptorTable::new();
+        gdt.add_entry(Descriptor::kernel_code_segment());
+        gdt.add_entry(Descriptor::tss_segment(&TSS));
+        gdt
+    };
+}
+
+pub fn init() {
+    GDT.load();
+}

src/interrupts.rs

@@ -0,0 +1,26 @@
+use lazy_static::lazy_static;
+use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
+
+lazy_static! {
+    static ref IDT: InterruptDescriptorTable = {
+        let mut idt = InterruptDescriptorTable::new();
+        idt.breakpoint.set_handler_fn(breakpoint_handler);
+        idt.double_fault.set_handler_fn(double_fault_handler);
+        idt
+    };
+}
+pub fn init_idt() {
+    IDT.load();
+}
+
+extern "x86-interrupt" fn breakpoint_handler(stack_frame: InterruptStackFrame) {
+    println!("EXCEPTION: Breakpoint\n{:#?}", stack_frame);
+}
+
+// The error code of the double-fault handler is always 0
+extern "x86-interrupt" fn double_fault_handler(
+    stack_frame: InterruptStackFrame,
+    _error_code: u64,
+) -> ! {
+    panic!("Exception: Double fault\n{:#?}", stack_frame)
+}

src/main.rs

@@ -1,4 +1,4 @@
-// #![feature(abi_x86_interrupt, asm)]
+#![feature(abi_x86_interrupt)]
 #![no_std]
 #![no_main]
 #![feature(custom_test_frameworks)]
@@ -9,6 +9,8 @@
 mod vga_buffer;
 #[macro_use]
 mod serial;
+mod gdt;
+mod interrupts;
 mod test_utils;
 
 #[cfg(not(test))]
@@ -24,6 +26,12 @@ pub extern "C" fn _start() -> ! {
     test_main();
 
     println!("Gamarjoba, munde!");
+    init();
+
+    // Deliberate breakpoint exception
+    x86_64::instructions::interrupts::int3();
+
+    println!("We're here now");
     loop {}
 }
 
@@ -36,3 +44,8 @@ fn basic_test() {
 fn basic_test2() {
     assert_eq!(4, 4);
 }
+
+pub fn init() {
+    gdt::init();
+    interrupts::init_idt();
+}