From 67df24a850b6dc070382289d09c70e369726cac4 Mon Sep 17 00:00:00 2001
From: Dennis Kobert <dennis@kobert.dev>
Date: Fri, 15 Nov 2019 07:32:54 +0100
Subject: Add protection fault handler

---
 kernel/src/interrupts/exceptions.rs | 26 ++++++++++++++++++++------
 kernel/src/interrupts/idt.rs        |  2 ++
 kernel/src/interrupts/mod.rs        | 11 ++++++-----
 kernel/tests/int3.rs                |  2 +-
 kernel/tests/stack_overflow.rs      |  2 +-
 5 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/kernel/src/interrupts/exceptions.rs b/kernel/src/interrupts/exceptions.rs
index f6d5176..a3ecf9d 100644
--- a/kernel/src/interrupts/exceptions.rs
+++ b/kernel/src/interrupts/exceptions.rs
@@ -13,10 +13,10 @@ macro_rules! exception_default {
     };
 }
 
-static mut expected_fault: Interrupts = Interrupts::NONE;
+static mut expected_fault: Interrupts = Interrupts::None;
 
 pub unsafe fn expect_fault(int: Interrupts) {
-    if expected_fault == Interrupts::NONE {
+    if expected_fault == Interrupts::None {
         expected_fault = int;
     }
 }
@@ -27,7 +27,7 @@ fn get_expected_fault() -> Interrupts {
 
 pub extern "x86-interrupt" fn breakpoint_handler(stack_frame: &mut InterruptStackFrame) {
     match get_expected_fault() {
-        Interrupts::BREAKPOINT => qemu::exit_qemu(qemu::QemuExitCode::Success),
+        Interrupts::Breakpoint => qemu::exit_qemu(qemu::QemuExitCode::Success),
         _ => panic!(
             "BREAKPOINT exception thrown\n\n{}",
             exception_default!(stack_frame)
@@ -35,6 +35,20 @@ pub extern "x86-interrupt" fn breakpoint_handler(stack_frame: &mut InterruptStac
     }
 }
 
+pub extern "x86-interrupt" fn general_protection_fault_handler(
+    stack_frame: &mut InterruptStackFrame,
+    error_code: u64,
+) {
+    match get_expected_fault() {
+        Interrupts::GeneralProtectionFault => qemu::exit_qemu(qemu::QemuExitCode::Success),
+        _ => panic!(
+            "GENERAL PROTECTION exception thrown\nerror code: {:x}\n{}",
+            error_code,
+            exception_default!(stack_frame)
+        ),
+    }
+}
+
 pub extern "x86-interrupt" fn page_fault_handler(
     stack_frame: &mut InterruptStackFrame,
     error_code: PageFaultErrorCode,
@@ -42,7 +56,7 @@ pub extern "x86-interrupt" fn page_fault_handler(
     use x86_64::registers::control::Cr2;
 
     match get_expected_fault() {
-        Interrupts::PAGE_FAULT => qemu::exit_qemu(qemu::QemuExitCode::Success),
+        Interrupts::PageFault => qemu::exit_qemu(qemu::QemuExitCode::Success),
         _ => panic!(
             "PAGE FAULT while accessing address: 0x{:08x}\nerror code: {:?}(0x{:x})\n{}",
             Cr2::read().as_u64(),
@@ -58,7 +72,7 @@ pub extern "x86-interrupt" fn segment_not_present_handler(
     error_code: u64,
 ) {
     match get_expected_fault() {
-        Interrupts::NOT_PRESENT => qemu::exit_qemu(qemu::QemuExitCode::Success),
+        Interrupts::NotPresent => qemu::exit_qemu(qemu::QemuExitCode::Success),
         _ => panic!(
             "SEGMENT NOT PRESENT exception\nerror code: 0x{:x}\n{}",
             error_code,
@@ -72,7 +86,7 @@ pub extern "x86-interrupt" fn double_fault_handler(
     _error_code: u64, // code is always zero
 ) {
     match get_expected_fault() {
-        Interrupts::NOT_PRESENT => qemu::exit_qemu(qemu::QemuExitCode::Success),
+        Interrupts::DoubleFault => qemu::exit_qemu(qemu::QemuExitCode::Success),
         _ => panic!(
             "DOUBLE FAULT\nthis is a fatal exception\n{}",
             exception_default!(stack_frame)
diff --git a/kernel/src/interrupts/idt.rs b/kernel/src/interrupts/idt.rs
index 9541f22..e85ef5a 100644
--- a/kernel/src/interrupts/idt.rs
+++ b/kernel/src/interrupts/idt.rs
@@ -8,6 +8,8 @@ lazy_static! {
             .set_handler_fn(super::exceptions::breakpoint_handler);
         idt.segment_not_present
             .set_handler_fn(super::exceptions::segment_not_present_handler);
+        idt.general_protection_fault
+            .set_handler_fn(super::exceptions::general_protection_fault_handler);
         unsafe {
             idt.double_fault
                 .set_handler_fn(super::exceptions::double_fault_handler)
diff --git a/kernel/src/interrupts/mod.rs b/kernel/src/interrupts/mod.rs
index 4ff3c4d..087a59c 100644
--- a/kernel/src/interrupts/mod.rs
+++ b/kernel/src/interrupts/mod.rs
@@ -5,9 +5,10 @@ pub mod idt;
 #[repr(usize)]
 #[derive(PartialEq, Clone, Copy)]
 pub enum Interrupts {
-    NONE,
-    PAGE_FAULT,
-    DOUBLE_FAULT,
-    NOT_PRESENT,
-    BREAKPOINT,
+    None,
+    PageFault,
+    DoubleFault,
+    NotPresent,
+    Breakpoint,
+    GeneralProtectionFault,
 }
diff --git a/kernel/tests/int3.rs b/kernel/tests/int3.rs
index f4e2116..f5b5470 100644
--- a/kernel/tests/int3.rs
+++ b/kernel/tests/int3.rs
@@ -13,7 +13,7 @@ use kernel::io::qemu;
 extern "C" fn _start() -> ! {
     kernel::init();
     unsafe {
-        exceptions::expect_fault(interrupts::Interrupts::BREAKPOINT);
+        exceptions::expect_fault(interrupts::Interrupts::Breakpoint);
     }
     x86_64::instructions::interrupts::int3();
     panic!("BREAKPOINT not caught");
diff --git a/kernel/tests/stack_overflow.rs b/kernel/tests/stack_overflow.rs
index eedb3b5..9e75f59 100644
--- a/kernel/tests/stack_overflow.rs
+++ b/kernel/tests/stack_overflow.rs
@@ -14,7 +14,7 @@ use kernel::io::qemu;
 extern "C" fn _start() -> ! {
     kernel::init();
     unsafe {
-        exceptions::expect_fault(interrupts::Interrupts::NOT_PRESENT);
+        exceptions::expect_fault(interrupts::Interrupts::PageFault);
     }
     _loop(0);
     panic!("PAGE_FAULT not caught");
-- 
cgit v1.2.3-54-g00ecf