From 64362cb41728c8b5e751361c569e3ecccb2b3734 Mon Sep 17 00:00:00 2001
From: valentinbreiz <valentinbreiz@gmail.com>
Date: Tue, 8 Feb 2022 20:55:55 +0000
Subject: [PATCH 1/2] Disable interrupt when touching memory

---
 source/Cosmos.Core/Memory/Heap.cs | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/source/Cosmos.Core/Memory/Heap.cs b/source/Cosmos.Core/Memory/Heap.cs
index 4d6c3a4e51..9c3d3fd403 100644
--- a/source/Cosmos.Core/Memory/Heap.cs
+++ b/source/Cosmos.Core/Memory/Heap.cs
@@ -39,17 +39,25 @@ public static unsafe void Init()
         /// <returns>Byte pointer to the start of the block.</returns>
         public static byte* Alloc(uint aSize)
         {
+            CPU.DisableInterrupts();
+
             if (aSize <= HeapSmall.mMaxItemSize)
             {
-                return HeapSmall.Alloc((ushort)aSize);
+                byte* ptr = HeapSmall.Alloc((ushort)aSize);
+                CPU.EnableInterrupts();
+                return ptr;
             }
             else if (aSize <= HeapMedium.MaxItemSize)
             {
-                return HeapMedium.Alloc(aSize);
+                byte* ptr = HeapMedium.Alloc(aSize);
+                CPU.EnableInterrupts();
+                return ptr;
             }
             else
             {
-                return HeapLarge.Alloc(aSize);
+                byte* ptr = HeapLarge.Alloc(aSize);
+                CPU.EnableInterrupts();
+                return ptr;
             }
         }
 
@@ -77,6 +85,8 @@ public static uint SafeAlloc(uint aSize)
         /// </exception>
         public static void Free(void* aPtr)
         {
+            CPU.DisableInterrupts();
+
             //TODO find a better way to remove the double look up here for GetPageType and then again in the
             // .Free methods which actually free the entries in the RAT.
             //Debugger.DoSendNumber(0x77);
@@ -95,6 +105,8 @@ public static void Free(void* aPtr)
                 default:
                     throw new Exception("Heap item not found in RAT.");
             }
+
+            CPU.EnableInterrupts();
         }
 
         /// <summary>

From 3fdb336988a789df3c9a8d8165d35b4c260dbfee Mon Sep 17 00:00:00 2001
From: valentinbreiz <valentinbreiz@gmail.com>
Date: Wed, 9 Feb 2022 16:19:38 +0000
Subject: [PATCH 2/2] Disable interrupts in Heap.Collect, not free

---
 source/Cosmos.Core/Memory/Heap.cs | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/source/Cosmos.Core/Memory/Heap.cs b/source/Cosmos.Core/Memory/Heap.cs
index 9c3d3fd403..69fee9c49a 100644
--- a/source/Cosmos.Core/Memory/Heap.cs
+++ b/source/Cosmos.Core/Memory/Heap.cs
@@ -85,8 +85,6 @@ public static uint SafeAlloc(uint aSize)
         /// </exception>
         public static void Free(void* aPtr)
         {
-            CPU.DisableInterrupts();
-
             //TODO find a better way to remove the double look up here for GetPageType and then again in the
             // .Free methods which actually free the entries in the RAT.
             //Debugger.DoSendNumber(0x77);
@@ -105,8 +103,6 @@ public static void Free(void* aPtr)
                 default:
                     throw new Exception("Heap item not found in RAT.");
             }
-
-            CPU.EnableInterrupts();
         }
 
         /// <summary>
@@ -115,6 +111,9 @@ public static void Free(void* aPtr)
         /// <returns>Number of objects freed</returns>
         public static int Collect()
         {
+			//Disable interrupts: Prevent CPU exception when allocation is called from interrupt code
+			CPU.DisableInterrupts();
+			
             // Mark and sweep objects from roots
             // 1. Check if a page is in use if medium/large mark and sweep object
             // 2. Go throught the SMT table for small objects and go through pages by size
@@ -234,6 +233,9 @@ public static int Collect()
 
                 rootSMTPtr = rootSMTPtr->LargerSize;
             }
+			
+			//Enable interrupts back
+			CPU.EnableInterrupts();
 
             return freed;
         }