From 084945688b0bea5d35b6cccb99d14c4f86398847 Mon Sep 17 00:00:00 2001
From: Greg Shuflin <greg.shuflin@protonmail.com>
Date: Mon, 4 Apr 2022 00:24:20 -0700
Subject: [PATCH] Interrupts: Handle double fault

---
 src/interrupts.rs | 9 +++++++++
 src/main.rs       | 3 +++
 2 files changed, 12 insertions(+)

diff --git a/src/interrupts.rs b/src/interrupts.rs
index 6cf20cd..d4d0fca 100644
--- a/src/interrupts.rs
+++ b/src/interrupts.rs
@@ -5,6 +5,7 @@ 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
     };
 }
@@ -15,3 +16,11 @@ pub fn init_idt() {
 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)
+}
diff --git a/src/main.rs b/src/main.rs
index 28e0323..87c4092 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -31,6 +31,9 @@ pub extern "C" fn _start() -> ! {
     x86_64::instructions::interrupts::int3();
 
     println!("We're here now");
+    unsafe {
+        *(0xff00ff00 as *mut u64) = 44;
+    }
     loop {}
 }