From 4c71e65cc595a01226653fc013ab41228fe2d3a5 Mon Sep 17 00:00:00 2001
From: Alexander Myltsev <a.myltsev@gmail.com>
Date: Sat, 18 Jan 2025 02:46:38 +0400
Subject: [PATCH] Kill usermode process on exceptions.

---
 cpu/idt.c | 7 +++++++
 proc.c    | 1 +
 2 files changed, 8 insertions(+)

diff --git a/cpu/idt.c b/cpu/idt.c
index ff4d3d8..91d8d02 100644
--- a/cpu/idt.c
+++ b/cpu/idt.c
@@ -105,6 +105,13 @@ void trap(registers_t *r) {
         if (r->int_no < ARRLEN(exception_messages)) {
             msg = exception_messages[r->int_no];
         }
+        if (r->cs & 3) {
+            // exception from user mode, kill offending process
+            printk("Exception: ");
+            printk(msg);
+            printk("\n");
+            killproc();
+        }
         panic(msg);
     }
 }
diff --git a/proc.c b/proc.c
index 851471b..4bacc84 100644
--- a/proc.c
+++ b/proc.c
@@ -82,6 +82,7 @@ _Noreturn void killproc() {
     void* task_stack;
     switchkvm();
     freevm(vm.user_task->pgdir);
+    sti();
     swtch(&task_stack, vm.kernel_thread);
     __builtin_unreachable();
 }