1 files changed, 64 insertions, 0 deletions
diff --git a/src/Ryujinx.HLE/HOS/Kernel/Threading/KCriticalSection.cs b/src/Ryujinx.HLE/HOS/Kernel/Threading/KCriticalSection.cs
new file mode 100644
index 00000000..1d61f2f0
--- /dev/null
+++ b/src/Ryujinx.HLE/HOS/Kernel/Threading/KCriticalSection.cs
@@ -0,0 +1,64 @@
+using System.Threading;
+
+namespace Ryujinx.HLE.HOS.Kernel.Threading
+{
+    class KCriticalSection
+    {
+        private readonly KernelContext _context;
+        private readonly object _lock;
+        private int _recursionCount;
+
+        public object Lock => _lock;
+
+        public KCriticalSection(KernelContext context)
+        {
+            _context = context;
+            _lock = new object();
+        }
+
+        public void Enter()
+        {
+            Monitor.Enter(_lock);
+
+            _recursionCount++;
+        }
+
+        public void Leave()
+        {
+            if (_recursionCount == 0)
+            {
+                return;
+            }
+
+            if (--_recursionCount == 0)
+            {
+                ulong scheduledCoresMask = KScheduler.SelectThreads(_context);
+
+                Monitor.Exit(_lock);
+
+                KThread currentThread = KernelStatic.GetCurrentThread();
+                bool isCurrentThreadSchedulable = currentThread != null && currentThread.IsSchedulable;
+                if (isCurrentThreadSchedulable)
+                {
+                    KScheduler.EnableScheduling(_context, scheduledCoresMask);
+                }
+                else
+                {
+                    KScheduler.EnableSchedulingFromForeignThread(_context, scheduledCoresMask);
+
+                    // If the thread exists but is not schedulable, we still want to suspend
+                    // it if it's not runnable. That allows the kernel to still block HLE threads
+                    // even if they are not scheduled on guest cores.
+                    if (currentThread != null && !currentThread.IsSchedulable && currentThread.Context.Running)
+                    {
+                        currentThread.SchedulerWaitEvent.WaitOne();
+                    }
+                }
+            }
+            else
+            {
+                Monitor.Exit(_lock);
+            }
+        }
+    }
+}
+\ No newline at end of file