Implement KCriticalSection (mostly)

mesosphere/source/threading/KConditionVariable.cpp

@@ -1,5 +1,5 @@
 #include <mesosphere/threading/KConditionVariable.hpp>
-#include <mesosphere/threading/KScheduler.hpp>
+#include <mesosphere/threading/KScopedCriticalSection.hpp>
 #include <mesosphere/core/KCoreContext.hpp>
 
 namespace mesosphere

mesosphere/source/threading/KCriticalSection.cpp

@@ -0,0 +1,45 @@
+#include <mesosphere/threading/KCriticalSection.hpp>
+#include <mesosphere/threading/KScheduler.hpp>
+#include <mesosphere/core/KCoreContext.hpp>
+
+namespace mesosphere
+{
+
+bool KCriticalSection::try_lock()
+{
+    KThread *curThread = KCoreContext::GetCurrentInstance().GetCurrentThread();
+    if (curThread == lockingThread) {
+        ++lockCount;
+        return true;
+    } else if (KInterruptSpinLock<false>::try_lock()) {
+        lockingThread = curThread;
+        lockCount = 1;
+        return true;
+    } else {
+        return false;
+    }
+}
+
+void KCriticalSection::lock()
+{
+    KThread *curThread = KCoreContext::GetCurrentInstance().GetCurrentThread();
+    if (curThread == lockingThread) {
+        ++lockCount;
+    } else {
+        KInterruptSpinLock<false>::lock();
+        lockingThread = curThread;
+        lockCount = 1;
+    }
+}
+
+void KCriticalSection::unlock()
+{
+    if (--lockCount == 0) {
+        lockingThread = nullptr;
+        KScheduler::HandleCriticalSectionLeave();
+    } else {
+        KInterruptSpinLock<false>::unlock();
+    }
+}
+
+}

mesosphere/source/threading/KMutex.cpp

@@ -1,6 +1,6 @@
 #include <mesosphere/threading/KMutex.hpp>
 #include <mesosphere/threading/KThread.hpp>
-#include <mesosphere/threading/KScheduler.hpp>
+#include <mesosphere/threading/KScopedCriticalSection.hpp>
 
 namespace mesosphere
 {

mesosphere/source/threading/KScheduler.cpp

@@ -341,4 +341,15 @@ void KScheduler::YieldCurrentThreadAndWaitForLoadBalancing()
     cctx.GetScheduler()->DoYieldOperation(Global::YieldThreadAndWaitForLoadBalancing, *cctx.GetCurrentThread());
 }
 
+void KScheduler::HandleCriticalSectionLeave()
+{
+    if (KScheduler::Global::reselectionRequired) {
+        KScheduler::Global::SelectThreads();
+    }
+
+    std::atomic_thread_fence(std::memory_order_seq_cst);
+
+    // TODO: check which cores needs ctx switches, sent interrupts and/or ctx switch ourselves
+}
+
 }

mesosphere/source/threading/KThread.cpp

@@ -3,7 +3,7 @@
 #include <algorithm>
 
 #include <mesosphere/threading/KThread.hpp>
-#include <mesosphere/threading/KScheduler.hpp>
+#include <mesosphere/threading/KScopedCriticalSection.hpp>
 
 namespace mesosphere
 {