From 8d6eab6b33ab59f74fc7bd3a93fc5a034284c90a Mon Sep 17 00:00:00 2001
From: Philipp Oppermann <dev@phil-opp.com>
Date: Sun, 13 Jan 2019 16:25:08 +0100
Subject: [PATCH] Add code for post

---
 src/interrupts.rs | 16 +++++++++++++++-
 src/main.rs       |  7 +++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/interrupts.rs b/src/interrupts.rs
index d9394d5c..1e96cf5c 100644
--- a/src/interrupts.rs
+++ b/src/interrupts.rs
@@ -7,7 +7,7 @@
 use crate::{gdt, print, println};
 use pic8259_simple::ChainedPics;
 use spin;
-use x86_64::structures::idt::{ExceptionStackFrame, InterruptDescriptorTable};
+use x86_64::structures::idt::{ExceptionStackFrame, InterruptDescriptorTable, PageFaultErrorCode};
 use lazy_static::lazy_static;
 
 pub const PIC_1_OFFSET: u8 = 32;
@@ -23,6 +23,7 @@ lazy_static! {
     static ref IDT: InterruptDescriptorTable = {
         let mut idt = InterruptDescriptorTable::new();
         idt.breakpoint.set_handler_fn(breakpoint_handler);
+        idt.page_fault.set_handler_fn(page_fault_handler);
         unsafe {
             idt.double_fault
                 .set_handler_fn(double_fault_handler)
@@ -44,6 +45,19 @@ extern "x86-interrupt" fn breakpoint_handler(stack_frame: &mut ExceptionStackFra
     println!("EXCEPTION: BREAKPOINT\n{:#?}", stack_frame);
 }
 
+extern "x86-interrupt" fn page_fault_handler(
+    stack_frame: &mut ExceptionStackFrame,
+    _error_code: PageFaultErrorCode,
+) {
+    use crate::hlt_loop;
+    use x86_64::registers::control::Cr2;
+
+    println!("EXCEPTION: PAGE FAULT");
+    println!("Accessed Address: {:?}", Cr2::read());
+    println!("{:#?}", stack_frame);
+    hlt_loop();
+}
+
 extern "x86-interrupt" fn double_fault_handler(
     stack_frame: &mut ExceptionStackFrame,
     _error_code: u64,
diff --git a/src/main.rs b/src/main.rs
index acf8e667..84cc237a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -12,9 +12,16 @@ use blog_os::println;
 #[no_mangle] // don't mangle the name of this function
 pub extern "C" fn _start() -> ! {
     use blog_os::interrupts::PICS;
+    use x86_64::structures::paging::PageTable;
 
     println!("Hello World{}", "!");
 
+    let level_4_table_ptr = 0xffff_ffff_ffff_f000 as *const PageTable;
+    let level_4_table = unsafe {&*level_4_table_ptr};
+    for i in 0..10 {
+        println!("Entry {}: {:?}", i, level_4_table[i]);
+    }
+
     blog_os::gdt::init();
     blog_os::interrupts::init_idt();
     unsafe { PICS.lock().initialize() };