From 3eb3c34275aeaa4375fc9a97fa90feb4b4a06349 Mon Sep 17 00:00:00 2001
From: Braiden Vasco <braiden-vasco@users.noreply.github.com>
Date: Fri, 3 Nov 2017 03:14:46 +0000
Subject: [PATCH] Add guards

---
 arch/config.h    | 10 ++++++++++
 arch/exception.c |  8 ++++++++
 arch/hwint.c     | 12 +++++++++++-
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/arch/config.h b/arch/config.h
index 6056b76..50071b4 100644
--- a/arch/config.h
+++ b/arch/config.h
@@ -20,4 +20,14 @@
 #define GDT_USER_CS_SELECTOR   GDT_SEGMENT_SELECTOR(GDT_USER_CS_INDEX)
 #define GDT_USER_DS_SELECTOR   GDT_SEGMENT_SELECTOR(GDT_USER_DS_INDEX)
 
+#define INT_EXCEPTION_COUNT 32
+#define INT_HWINT_COUNT     16
+#define INT_TOTAL_COUNT     (INT_EXCEPTION_COUNT + INT_HWINT_COUNT)
+
+#define INT_EXCEPTION_FIRST 0
+#define INT_EXCEPTION_LAST (INT_EXCEPTION_FIRST + INT_EXCEPTION_COUNT - 1)
+
+#define INT_HWINT_FIRST (INT_EXCEPTION_LAST + 1)
+#define INT_HWINT_LAST  (INT_HWINT_FIRST + INT_HWINT_COUNT - 1)
+
 #endif
diff --git a/arch/exception.c b/arch/exception.c
index 9676554..5e46dfd 100644
--- a/arch/exception.c
+++ b/arch/exception.c
@@ -1,3 +1,4 @@
+#include "config.h"
 #include "logger.h"
 
 struct IsrRegisters {
@@ -44,5 +45,12 @@ static const char *const messages[] = {
 
 void exception_handler(struct IsrRegisters regs)
 {
+    if (
+        !(regs.int_no >= INT_EXCEPTION_FIRST &&
+          regs.int_no <= INT_EXCEPTION_LAST)
+    ) {
+        return;
+    }
+
     logger_warn(messages[regs.int_no]);
 }
diff --git a/arch/hwint.c b/arch/hwint.c
index aafb9ee..bce0325 100644
--- a/arch/hwint.c
+++ b/arch/hwint.c
@@ -1,3 +1,4 @@
+#include "config.h"
 #include "logger.h"
 
 struct IsrRegisters {
@@ -28,5 +29,14 @@ static const char *const messages[] = {
 
 void hwint_handler(struct IsrRegisters regs)
 {
-    logger_warn(messages[regs.int_no - 32]);
+    if (
+        !(regs.int_no >= INT_HWINT_FIRST &&
+          regs.int_no <= INT_HWINT_LAST)
+    ) {
+        return;
+    }
+
+    const unsigned char hwint_no = regs.int_no - INT_HWINT_FIRST;
+
+    logger_warn(messages[hwint_no]);
 }