From ec22f3464c87b3d1b1688898053a569bc4839404 Mon Sep 17 00:00:00 2001
From: Dennis Kobert <dennis@kobert.dev>
Date: Mon, 11 Nov 2019 18:42:59 +0100
Subject: Add expect fault handling

---
 kernel/src/interrupts/exceptions.rs | 66 ++++++++++++++++++++++++++-----------
 1 file changed, 46 insertions(+), 20 deletions(-)

(limited to 'kernel/src/interrupts/exceptions.rs')

diff --git a/kernel/src/interrupts/exceptions.rs b/kernel/src/interrupts/exceptions.rs
index 1e7680a..f6d5176 100644
--- a/kernel/src/interrupts/exceptions.rs
+++ b/kernel/src/interrupts/exceptions.rs
@@ -1,3 +1,5 @@
+use super::Interrupts;
+use crate::io::qemu;
 use x86_64::structures::idt::{InterruptStackFrame, PageFaultErrorCode};
 
 macro_rules! exception_default {
@@ -11,11 +13,26 @@ macro_rules! exception_default {
     };
 }
 
+static mut expected_fault: Interrupts = Interrupts::NONE;
+
+pub unsafe fn expect_fault(int: Interrupts) {
+    if expected_fault == Interrupts::NONE {
+        expected_fault = int;
+    }
+}
+
+fn get_expected_fault() -> Interrupts {
+    unsafe { expected_fault }
+}
+
 pub extern "x86-interrupt" fn breakpoint_handler(stack_frame: &mut InterruptStackFrame) {
-    panic!(
-        "BREAKPOINT exception thrown\n\n{}",
-        exception_default!(stack_frame)
-    );
+    match get_expected_fault() {
+        Interrupts::BREAKPOINT => qemu::exit_qemu(qemu::QemuExitCode::Success),
+        _ => panic!(
+            "BREAKPOINT exception thrown\n\n{}",
+            exception_default!(stack_frame)
+        ),
+    }
 }
 
 pub extern "x86-interrupt" fn page_fault_handler(
@@ -24,32 +41,41 @@ pub extern "x86-interrupt" fn page_fault_handler(
 ) {
     use x86_64::registers::control::Cr2;
 
-    panic!(
-        "PAGE FAULT while accessing address: 0x{:08x}\nerror code: {:?}(0x{:x})\n{}",
-        Cr2::read().as_u64(),
-        error_code,
-        error_code.bits(),
-        exception_default!(stack_frame)
-    );
+    match get_expected_fault() {
+        Interrupts::PAGE_FAULT => qemu::exit_qemu(qemu::QemuExitCode::Success),
+        _ => panic!(
+            "PAGE FAULT while accessing address: 0x{:08x}\nerror code: {:?}(0x{:x})\n{}",
+            Cr2::read().as_u64(),
+            error_code,
+            error_code.bits(),
+            exception_default!(stack_frame)
+        ),
+    }
 }
 
 pub extern "x86-interrupt" fn segment_not_present_handler(
     stack_frame: &mut InterruptStackFrame,
     error_code: u64,
 ) {
-    panic!(
-        "SEGMENT NOT PRESENT exception\nerror code: 0x{:x}\n{}",
-        error_code,
-        exception_default!(stack_frame)
-    );
+    match get_expected_fault() {
+        Interrupts::NOT_PRESENT => qemu::exit_qemu(qemu::QemuExitCode::Success),
+        _ => panic!(
+            "SEGMENT NOT PRESENT exception\nerror code: 0x{:x}\n{}",
+            error_code,
+            exception_default!(stack_frame)
+        ),
+    }
 }
 
 pub extern "x86-interrupt" fn double_fault_handler(
     stack_frame: &mut InterruptStackFrame,
     _error_code: u64, // code is always zero
 ) {
-    panic!(
-        "DOUBLE FAULT\nthis is a fatal exception\n{}",
-        exception_default!(stack_frame)
-    );
+    match get_expected_fault() {
+        Interrupts::NOT_PRESENT => qemu::exit_qemu(qemu::QemuExitCode::Success),
+        _ => panic!(
+            "DOUBLE FAULT\nthis is a fatal exception\n{}",
+            exception_default!(stack_frame)
+        ),
+    }
 }
-- 
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