fix a few bugs in scheduling and synchronization, separate OVMF_VARS for debug

code/hal/hal_timer.c

@@ -23,7 +23,7 @@ static volatile uint32_t* gLapic = NULL;
 #define LAPIC_REG(off) (*(volatile uint32_t *)((uint8_t *)gLapic + (off)))
 
 static volatile uint64_t gTicks = 0;
-void (*gTimerCallback)(void) = NULL;
+void (* volatile gTimerCallback)(void) = NULL;
 
 static inline void outb(uint16_t port, uint8_t val) { __outbyte(port, val); }
 static inline uint8_t inb(uint16_t port)            { return __inbyte(port); }

code/kernel/ke_event.c

@@ -21,37 +21,35 @@ KSTATUS KeEventCreate(EVENT_TYPE type, uint32_t initialState, EVENT **out) {
 
 void KeSignalEvent(EVENT* event) {
     if (!event) return;
-    KeAcquireSpinlock(&event->Lock);
+    uintptr_t flags = KeAcquireSpinlock(&event->Lock);
 
     if (event->Type == EventManualReset) {
-        // Wake all waiters.
         event->Signaled = 1;
         while (!LIST_IS_EMPTY(&event->WaitList)) {
             LIST_ENTRY* node = ListPopHead(&event->WaitList);
             THREAD* t = CONTAINING_RECORD(node, THREAD, SchedulerLink);
-            KeReleaseSpinlock(&event->Lock);
+            KeReleaseSpinlock(&event->Lock, flags);
             KeUnblockThread(t);
-            KeAcquireSpinlock(&event->Lock);
+            flags = KeAcquireSpinlock(&event->Lock);
         }
     } else {
-        // Auto-reset: wake one waiter or set the flag for the next waiter.
         if (!LIST_IS_EMPTY(&event->WaitList)) {
             LIST_ENTRY* node = ListPopHead(&event->WaitList);
             THREAD* t = CONTAINING_RECORD(node, THREAD, SchedulerLink);
-            KeReleaseSpinlock(&event->Lock);
+            KeReleaseSpinlock(&event->Lock, flags);
             KeUnblockThread(t);
             return;
         }
         event->Signaled = 1;
     }
-    KeReleaseSpinlock(&event->Lock);
+    KeReleaseSpinlock(&event->Lock, flags);
 }
 
 void KeClearEvent(EVENT* event) {
     if (!event) return;
-    KeAcquireSpinlock(&event->Lock);
+    uintptr_t flags = KeAcquireSpinlock(&event->Lock);
     event->Signaled = 0;
-    KeReleaseSpinlock(&event->Lock);
+    KeReleaseSpinlock(&event->Lock, flags);
 }
 
 KSTATUS KeWaitForEvent(EVENT* event) {
@@ -59,14 +57,14 @@ KSTATUS KeWaitForEvent(EVENT* event) {
     THREAD* self = KeCurrentThread();
 
     for (;;) {
-        KeAcquireSpinlock(&event->Lock);
+        uintptr_t flags = KeAcquireSpinlock(&event->Lock);
         if (event->Signaled) {
             if (event->Type == EventAutoReset) event->Signaled = 0;
-            KeReleaseSpinlock(&event->Lock);
+            KeReleaseSpinlock(&event->Lock, flags);
             return STATUS_SUCCESS;
         }
         ListInsertTail(&event->WaitList, &self->SchedulerLink);
-        KeReleaseSpinlock(&event->Lock);
+        KeReleaseSpinlock(&event->Lock, flags);
         KeBlockThread(self, &event->Header);
     }
 }

code/kernel/ke_irq.c

@@ -14,12 +14,11 @@ void KeIrqInitialize(const HAL_API *hal) {
 void KeIrqRegister(uint8_t irq, void (*handler)(void)) {
     if (irq >= MAX_IRQS || !handler) return;
     gIrqHandlers[irq] = handler;
-    gHal->Intc.RouteIrq(irq);   // programs IOAPIC, clears mask bit
+    gHal->Intc.RouteIrq(irq);
 }
 
-// Called from KeIrqCommon in assembly - this is the only symbol
-// the assembly needs to know.
 void KeIrqDispatch(uint8_t irq) {
+    // eoi first, handler second because it doesn't work otherwise.
     gHal->Intc.SendEoi();
     if (irq < MAX_IRQS && gIrqHandlers[irq])
         gIrqHandlers[irq]();

code/kernel/ke_mutex.c

@@ -24,46 +24,42 @@ KSTATUS KeAcquireMutex(MUTEX* mutex) {
     THREAD* self = KeCurrentThread();
 
     for (;;) {
-        KeAcquireSpinlock(&mutex->Lock);
+        uintptr_t flags = KeAcquireSpinlock(&mutex->Lock);
         if (!mutex->Owner) {
             mutex->Owner = self;
-            KeReleaseSpinlock(&mutex->Lock);
+            KeReleaseSpinlock(&mutex->Lock, flags);
             return STATUS_SUCCESS;
         }
-        // Already owned - add self to wait list and block.
         ListInsertTail(&mutex->WaitList, &self->SchedulerLink);
-        KeReleaseSpinlock(&mutex->Lock);
+        KeReleaseSpinlock(&mutex->Lock, flags);
         KeBlockThread(self, &mutex->Header);
-        // KeBlockThread calls KeYield; when we return here we've been
-        // unblocked by KeReleaseMutex - loop back and try to own it.
     }
 }
 
 KSTATUS KeTryAcquireMutex(MUTEX* mutex) {
     if (!mutex) return STATUS_INVALID_PARAMETER;
     THREAD* self = KeCurrentThread();
-    KeAcquireSpinlock(&mutex->Lock);
+    uintptr_t flags = KeAcquireSpinlock(&mutex->Lock);
     if (!mutex->Owner) {
         mutex->Owner = self;
-        KeReleaseSpinlock(&mutex->Lock);
+        KeReleaseSpinlock(&mutex->Lock, flags);
         return STATUS_SUCCESS;
     }
-    KeReleaseSpinlock(&mutex->Lock);
+    KeReleaseSpinlock(&mutex->Lock, flags);
     return STATUS_FAILURE;
 }
 
 void KeReleaseMutex(MUTEX* mutex) {
     if (!mutex) return;
-    KeAcquireSpinlock(&mutex->Lock);
+    uintptr_t flags = KeAcquireSpinlock(&mutex->Lock);
     mutex->Owner = (struct THREAD *)0;
 
-    // Wake the first waiter, if any.
     if (!LIST_IS_EMPTY(&mutex->WaitList)) {
         LIST_ENTRY* node = ListPopHead(&mutex->WaitList);
         THREAD* waiter   = CONTAINING_RECORD(node, THREAD, SchedulerLink);
-        KeReleaseSpinlock(&mutex->Lock);
+        KeReleaseSpinlock(&mutex->Lock, flags);
         KeUnblockThread(waiter);
         return;
     }
-    KeReleaseSpinlock(&mutex->Lock);
+    KeReleaseSpinlock(&mutex->Lock, flags);
 }

code/kernel/ke_process.c

@@ -1,6 +1,6 @@
 // ke_process.c - process model
 #include "ke_process.h"
-#include "ke_thread.h"    // KeExitThread (forward declared below)
+#include "ke_thread.h"
 #include "mm_virt.h"
 #include "ob_object.h"
 #include <string.h>
@@ -41,9 +41,9 @@ static void ProcessDestroy(OBJECT* obj) {
     }
 
     // Remove from global list.
-    KeAcquireSpinlock(&gProcessListLock);
+    uintptr_t flags = KeAcquireSpinlock(&gProcessListLock);
     ListRemove(&proc->GlobalLink);
-    KeReleaseSpinlock(&gProcessListLock);
+    KeReleaseSpinlock(&gProcessListLock, flags);
 
     // Memory for the struct itself is freed by ObDereferenceObject after
     // Destroy returns.
@@ -76,9 +76,9 @@ KSTATUS KeCreateProcess(const char* name, PROCESS **out) {
 
     LIST_INIT(&proc->GlobalLink);
 
-    KeAcquireSpinlock(&gProcessListLock);
+    uintptr_t flags = KeAcquireSpinlock(&gProcessListLock);
     ListInsertTail(&gProcessList, &proc->GlobalLink);
-    KeReleaseSpinlock(&gProcessListLock);
+    KeReleaseSpinlock(&gProcessListLock, flags);
 
     *out = proc;
     return STATUS_SUCCESS;
@@ -101,43 +101,43 @@ void KeExitProcess(PROCESS* process, int exitCode) {
 KSTATUS KeAllocateHandle(PROCESS* process, OBJECT* object, uint32_t* handleOut) {
     if (!process || !object || !handleOut) return STATUS_INVALID_PARAMETER;
 
-    KeAcquireSpinlock(&process->HandleLock);
+    uintptr_t flags = KeAcquireSpinlock(&process->HandleLock);
 
     for (int i = 1; i < HANDLE_TABLE_SIZE; i++) {
         if (!process->Handles[i]) {
             ObReferenceObject(object);
             process->Handles[i] = object;
             *handleOut = (uint32_t)i;
-            KeReleaseSpinlock(&process->HandleLock);
+            KeReleaseSpinlock(&process->HandleLock, flags);
             return STATUS_SUCCESS;
         }
     }
 
-    KeReleaseSpinlock(&process->HandleLock);
+    KeReleaseSpinlock(&process->HandleLock, flags);
     return STATUS_NO_MEMORY;
 }
 
 void KeCloseHandle(PROCESS* process, uint32_t handle) {
     if (!process || handle == 0 || handle >= HANDLE_TABLE_SIZE) return;
 
-    KeAcquireSpinlock(&process->HandleLock);
+    uintptr_t flags = KeAcquireSpinlock(&process->HandleLock);
     OBJECT* obj = process->Handles[handle];
     if (obj) {
         process->Handles[handle] = (OBJECT *)0;
-        KeReleaseSpinlock(&process->HandleLock);
+        KeReleaseSpinlock(&process->HandleLock, flags);
         ObDereferenceObject(obj);
         return;
     }
-    KeReleaseSpinlock(&process->HandleLock);
+    KeReleaseSpinlock(&process->HandleLock, flags);
 }
 
 OBJECT* KeLookupHandle(PROCESS* process, uint32_t handle) {
     if (!process || handle == 0 || handle >= HANDLE_TABLE_SIZE)
         return (OBJECT *)0;
 
-    KeAcquireSpinlock(&process->HandleLock);
+    uintptr_t flags = KeAcquireSpinlock(&process->HandleLock);
     OBJECT* obj = process->Handles[handle];
     if (obj) ObReferenceObject(obj);
-    KeReleaseSpinlock(&process->HandleLock);
+    KeReleaseSpinlock(&process->HandleLock, flags);
     return obj;
 }

code/kernel/ke_queue.c

@@ -25,7 +25,7 @@ KSTATUS KeSendMessage(QUEUE* queue, const QUEUE_MESSAGE* msg, bool blocking) {
     THREAD* self = KeCurrentThread();
 
     for (;;) {
-        KeAcquireSpinlock(&queue->Lock);
+        uintptr_t flags = KeAcquireSpinlock(&queue->Lock);
         if (queue->Count < QUEUE_DEPTH) {
             queue->Ring[queue->Tail] = *msg;
             queue->Tail = (queue->Tail + 1) % QUEUE_DEPTH;
@@ -35,19 +35,19 @@ KSTATUS KeSendMessage(QUEUE* queue, const QUEUE_MESSAGE* msg, bool blocking) {
             if (!LIST_IS_EMPTY(&queue->RecvWaiters)) {
                 LIST_ENTRY* node = ListPopHead(&queue->RecvWaiters);
                 THREAD* t = CONTAINING_RECORD(node, THREAD, SchedulerLink);
-                KeReleaseSpinlock(&queue->Lock);
+                KeReleaseSpinlock(&queue->Lock, flags);
                 KeUnblockThread(t);
             } else {
-                KeReleaseSpinlock(&queue->Lock);
+                KeReleaseSpinlock(&queue->Lock, flags);
             }
             return STATUS_SUCCESS;
         }
         if (!blocking) {
-            KeReleaseSpinlock(&queue->Lock);
+            KeReleaseSpinlock(&queue->Lock, flags);
             return STATUS_QUEUE_FULL;
         }
         ListInsertTail(&queue->SendWaiters, &self->SchedulerLink);
-        KeReleaseSpinlock(&queue->Lock);
+        KeReleaseSpinlock(&queue->Lock, flags);
         KeBlockThread(self, &queue->Header);
     }
 }
@@ -57,7 +57,7 @@ KSTATUS KeReceiveMessage(QUEUE* queue, QUEUE_MESSAGE* msg, bool blocking) {
     THREAD* self = KeCurrentThread();
 
     for (;;) {
-        KeAcquireSpinlock(&queue->Lock);
+        uintptr_t flags = KeAcquireSpinlock(&queue->Lock);
         if (queue->Count > 0) {
             *msg = queue->Ring[queue->Head];
             queue->Head = (queue->Head + 1) % QUEUE_DEPTH;
@@ -67,19 +67,19 @@ KSTATUS KeReceiveMessage(QUEUE* queue, QUEUE_MESSAGE* msg, bool blocking) {
             if (!LIST_IS_EMPTY(&queue->SendWaiters)) {
                 LIST_ENTRY* node = ListPopHead(&queue->SendWaiters);
                 THREAD* t = CONTAINING_RECORD(node, THREAD, SchedulerLink);
-                KeReleaseSpinlock(&queue->Lock);
+                KeReleaseSpinlock(&queue->Lock, flags);
                 KeUnblockThread(t);
             } else {
-                KeReleaseSpinlock(&queue->Lock);
+                KeReleaseSpinlock(&queue->Lock, flags);
             }
             return STATUS_SUCCESS;
         }
         if (!blocking) {
-            KeReleaseSpinlock(&queue->Lock);
+            KeReleaseSpinlock(&queue->Lock, flags);
             return STATUS_QUEUE_EMPTY;
         }
         ListInsertTail(&queue->RecvWaiters, &self->SchedulerLink);
-        KeReleaseSpinlock(&queue->Lock);
+        KeReleaseSpinlock(&queue->Lock, flags);
         KeBlockThread(self, &queue->Header);
     }
 }

code/kernel/ke_sched.c

@@ -1,15 +1,4 @@
 // ke_sched.c - MLFQ scheduler
-//
-// Three queues: PriorityHigh(2), PriorityNormal(1), PriorityLow(0).
-// Dispatch always picks the highest non-empty queue.
-// Within a queue: strict round-robin.
-//
-// Demotion threshold: a thread that consumes DEMOTION_QUANTA consecutive
-// ticks without blocking drops one level (floor PriorityLow).
-// Promotion: a thread that unblocks is bumped one level (ceiling PriorityHigh).
-//
-// The idle thread (created by KeInitializeScheduler) runs at PriorityLow
-// when nothing else is runnable.
 #include "ke_sched.h"
 #include "ke_thread.h"
 #include "ke_spinlock.h"
@@ -17,44 +6,27 @@
 #include "mm_virt.h"
 #include <stddef.h>
 
-#define DEMOTION_QUANTA  4   /* ticks at a level before demotion */
+#define DEMOTION_QUANTA  4 /* ticks at a level before demotion */
 
-// ---------------------------------------------------------------------------
-// Run queues
-// ---------------------------------------------------------------------------
-static LIST_ENTRY gRunQueue[PriorityCount];   // [0]=Low [1]=Normal [2]=High
+static LIST_ENTRY gRunQueue[PriorityCount];
 static SPINLOCK   gSchedLock;
 
-// The currently running thread (also in GS:[0] for fast access).
-// On a single-core system this is the only "per-CPU" slot we need.
 static THREAD* gCurrentThread;
 static THREAD* gIdleThread;
+static THREAD* gOutgoingThread;
+static uint32_t gAgingCounter = 0;
 
-// ---------------------------------------------------------------------------
-// GS:[0] helpers - implemented in ke_switch.asm
-// (On single-core we just use a global; SMP would use per-core GS.)
-// ---------------------------------------------------------------------------
 THREAD* KeCurrentThread(void)        { return gCurrentThread; }
 void    KeSetCurrentThread(THREAD* t){ gCurrentThread = t; }
 
-// ---------------------------------------------------------------------------
-// Idle thread body - runs in ring 0 when every other thread is blocked.
-// ---------------------------------------------------------------------------
 static void IdleLoop(void) {
     for (;;) { __halt(); }
 }
 
-// ---------------------------------------------------------------------------
-// Init
-// ---------------------------------------------------------------------------
 void KeInitializeScheduler(void) {
     for (int i = 0; i < PriorityCount; i++) LIST_INIT(&gRunQueue[i]);
     gSchedLock = (SPINLOCK)SPINLOCK_INIT;
 
-    // Create the idle process / thread.
-    // We call the internal alloc directly to avoid the full KeCreateThread
-    // path (no user stack, no ring-3 entry - the idle thread never leaves
-    // ring 0 and never calls KeExitThread).
     extern KSTATUS KeCreateProcess(const char *, PROCESS **);
     PROCESS* idleProc;
     KeCreateProcess("idle", &idleProc);
@@ -67,13 +39,13 @@ void KeInitializeScheduler(void) {
     idle->QuantaConsumed  = 0;
     idle->Owner           = idleProc;
     idle->WaitObject      = (OBJECT *)0;
+    idle->SchedLockFlags  = 0x202ULL; // IF=1
 
     void* kstack = MmAllocatePool(KSTACK_SIZE);
     idle->KernelStackBase = kstack;
     idle->KernelStackTop  = (uintptr_t)kstack + KSTACK_SIZE;
     idle->TssRsp0         = idle->KernelStackTop;
 
-    // Initial context: RSP at top of kstack, Rip = IdleLoop.
     uintptr_t* ksp = (uintptr_t *)idle->KernelStackTop;
     ksp -= sizeof(KCONTEXT) / sizeof(uintptr_t);
     KCONTEXT* ctx = (KCONTEXT *)ksp;
@@ -83,13 +55,20 @@ void KeInitializeScheduler(void) {
 
     gIdleThread    = idle;
     gCurrentThread = idle;
-
-    // Don't add idle to the run queue here; KeSchedulerTick falls back to it.
 }
 
-// ---------------------------------------------------------------------------
-// Run-queue management
-// ---------------------------------------------------------------------------
+// Safely release the lock and clean up any dead threads natively post-switch
+void KeSchedulerPostSwitch(void) {
+    THREAD* cur = KeCurrentThread();
+    KeReleaseSpinlock(&gSchedLock, cur->SchedLockFlags);
+
+    if (gOutgoingThread && gOutgoingThread->State == ThreadDead) {
+        THREAD* dead = gOutgoingThread;
+        gOutgoingThread = (THREAD*)0;
+        ObDereferenceObject(&dead->Header);
+    }
+}
+
 void KeReadyThread(THREAD* thread) {
     if (!thread) return;
     thread->State = ThreadReady;
@@ -97,22 +76,18 @@ void KeReadyThread(THREAD* thread) {
     if (p < 0) p = 0;
     if (p >= PriorityCount) p = PriorityCount - 1;
 
-    KeAcquireSpinlock(&gSchedLock);
+    uintptr_t flags = KeAcquireSpinlock(&gSchedLock);
     ListInsertTail(&gRunQueue[p], &thread->SchedulerLink);
-    KeReleaseSpinlock(&gSchedLock);
+    KeReleaseSpinlock(&gSchedLock, flags);
 }
 
 void KeUnreadyThread(THREAD* thread) {
     if (!thread) return;
-    KeAcquireSpinlock(&gSchedLock);
+    uintptr_t flags = KeAcquireSpinlock(&gSchedLock);
     ListRemove(&thread->SchedulerLink);
-    KeReleaseSpinlock(&gSchedLock);
+    KeReleaseSpinlock(&gSchedLock, flags);
 }
 
-// ---------------------------------------------------------------------------
-// Pick the highest-priority runnable thread (caller holds gSchedLock).
-// Returns gIdleThread if all queues are empty.
-// ---------------------------------------------------------------------------
 static THREAD* PickNext(void) {
     for (int p = PriorityCount - 1; p >= 0; p--) {
         if (!LIST_IS_EMPTY(&gRunQueue[p])) {
@@ -124,18 +99,15 @@ static THREAD* PickNext(void) {
     return gIdleThread;
 }
 
-// ---------------------------------------------------------------------------
-// KeSchedulerTick - called from the timer ISR every QUANTUM_MS
-// ---------------------------------------------------------------------------
 void KeSchedulerTick(void) {
     THREAD* cur = gCurrentThread;
     if (!cur) return;
 
-    KeAcquireSpinlock(&gSchedLock);
+    uintptr_t flags = KeAcquireSpinlock(&gSchedLock);
+    cur->SchedLockFlags = flags; // Issue 5 fix
 
     cur->QuantaConsumed++;
 
-    // Demotion: CPU-bound thread exhausted its quanta budget.
     if (cur != gIdleThread && cur->QuantaConsumed >= DEMOTION_QUANTA) {
         cur->QuantaConsumed = 0;
         if (cur->Priority > PriorityLow) {
@@ -143,51 +115,56 @@ void KeSchedulerTick(void) {
         }
     }
 
-    // Check if a higher-priority thread is waiting.
+    // Periodic aging pass to prevent indefinite starvation of PriorityLow threads
+    gAgingCounter++;
+    if (gAgingCounter >= 100) {
+        gAgingCounter = 0;
+        for (int p = 0; p < PriorityHigh; p++) {
+            while (!LIST_IS_EMPTY(&gRunQueue[p])) {
+                LIST_ENTRY* node = ListPopHead(&gRunQueue[p]);
+                THREAD* t = CONTAINING_RECORD(node, THREAD, SchedulerLink);
+                t->Priority = PriorityHigh;
+                ListInsertTail(&gRunQueue[PriorityHigh], &t->SchedulerLink);
+            }
+        }
+    }
+
     THREAD* next = PickNext();
     if (next == cur) {
-        // Re-insert ourselves and continue.
         if (cur != gIdleThread) {
             ListInsertTail(&gRunQueue[cur->Priority], &cur->SchedulerLink);
         }
-        KeReleaseSpinlock(&gSchedLock);
+        KeReleaseSpinlock(&gSchedLock, flags);
         return;
     }
 
-    // Switch.
-    cur->State  = (cur == gIdleThread) ? ThreadReady : ThreadReady;
+    cur->State  = ThreadReady;
     next->State = ThreadRunning;
     gCurrentThread = next;
 
-    // Re-queue the outgoing thread if it is still runnable.
     if (cur != gIdleThread && cur->State == ThreadReady) {
         ListInsertTail(&gRunQueue[cur->Priority], &cur->SchedulerLink);
     }
 
-    KeReleaseSpinlock(&gSchedLock);
+    gOutgoingThread = cur;
     KeSwitchContext(cur, next);
+    KeSchedulerPostSwitch();
 }
 
-// ---------------------------------------------------------------------------
-// KeYield
-// ---------------------------------------------------------------------------
 void KeYield(void) {
     THREAD* cur = gCurrentThread;
     if (!cur) return;
 
-    KeAcquireSpinlock(&gSchedLock);
+    uintptr_t flags = KeAcquireSpinlock(&gSchedLock);
+    cur->SchedLockFlags = flags;
 
-    // Voluntary block → promote one level.
-    if (cur != gIdleThread && cur->Priority < PriorityHigh) {
-        cur->Priority = (THREAD_PRIORITY)(cur->Priority + 1);
-        cur->QuantaConsumed = 0;
-    }
+    // Issue 4 Fix: Deleted misleading voluntary promotion from here.
     
     THREAD* next = PickNext();
     if (next == cur) {
         if (cur != gIdleThread)
             ListInsertTail(&gRunQueue[cur->Priority], &cur->SchedulerLink);
-        KeReleaseSpinlock(&gSchedLock);
+        KeReleaseSpinlock(&gSchedLock, flags);
         return;
     }
 
@@ -197,6 +174,7 @@ void KeYield(void) {
     if (cur != gIdleThread && cur->State == ThreadReady)
         ListInsertTail(&gRunQueue[cur->Priority], &cur->SchedulerLink);
 
-    KeReleaseSpinlock(&gSchedLock);
+    gOutgoingThread = cur;
     KeSwitchContext(cur, next);
+    KeSchedulerPostSwitch();
 }

code/kernel/ke_semaphore.c

@@ -25,40 +25,40 @@ KSTATUS KeWaitSemaphore(SEMAPHORE* sem) {
     THREAD* self = KeCurrentThread();
 
     for (;;) {
-        KeAcquireSpinlock(&sem->Lock);
+        uintptr_t flags = KeAcquireSpinlock(&sem->Lock);
         if (sem->Count > 0) {
             sem->Count--;
-            KeReleaseSpinlock(&sem->Lock);
+            KeReleaseSpinlock(&sem->Lock, flags);
             return STATUS_SUCCESS;
         }
         ListInsertTail(&sem->WaitList, &self->SchedulerLink);
-        KeReleaseSpinlock(&sem->Lock);
+        KeReleaseSpinlock(&sem->Lock, flags);
         KeBlockThread(self, &sem->Header);
     }
 }
 
 KSTATUS KeTrySemaphore(SEMAPHORE* sem) {
     if (!sem) return STATUS_INVALID_PARAMETER;
-    KeAcquireSpinlock(&sem->Lock);
+    uintptr_t flags = KeAcquireSpinlock(&sem->Lock);
     if (sem->Count > 0) {
         sem->Count--;
-        KeReleaseSpinlock(&sem->Lock);
+        KeReleaseSpinlock(&sem->Lock, flags);
         return STATUS_SUCCESS;
     }
-    KeReleaseSpinlock(&sem->Lock);
+    KeReleaseSpinlock(&sem->Lock, flags);
     return STATUS_FAILURE;
 }
 
 void KeSignalSemaphore(SEMAPHORE* sem) {
     if (!sem) return;
-    KeAcquireSpinlock(&sem->Lock);
+    uintptr_t flags = KeAcquireSpinlock(&sem->Lock);
     if (!LIST_IS_EMPTY(&sem->WaitList)) {
         LIST_ENTRY* node = ListPopHead(&sem->WaitList);
         THREAD* waiter   = CONTAINING_RECORD(node, THREAD, SchedulerLink);
-        KeReleaseSpinlock(&sem->Lock);
+        KeReleaseSpinlock(&sem->Lock, flags);
         KeUnblockThread(waiter);
         return;
     }
     if (sem->Count < sem->MaxCount) sem->Count++;
-    KeReleaseSpinlock(&sem->Lock);
+    KeReleaseSpinlock(&sem->Lock, flags);
 }

code/kernel/ke_spinlock.h

@@ -10,15 +10,28 @@ typedef struct SPINLOCK {
 
 #define SPINLOCK_INIT  { 0 }
 
-static __forceinline void KeAcquireSpinlock(SPINLOCK* sl) {
+// Issue 1 Fix: Save EFLAGS, disable interrupts, and return old flags.
+static __forceinline uintptr_t KeAcquireSpinlock(SPINLOCK* sl) {
+    uintptr_t flags = __readeflags();
+    _disable();
     while (_InterlockedCompareExchange(&sl->Locked, 1, 0) != 0)
         _mm_pause();
+    return flags;
 }
 
-static __forceinline void KeReleaseSpinlock(SPINLOCK* sl) {
+// Issue 1 Fix: Restore EFLAGS upon release.
+static __forceinline void KeReleaseSpinlock(SPINLOCK* sl, uintptr_t flags) {
     _InterlockedExchange(&sl->Locked, 0);
+    __writeeflags(flags);
 }
 
-static __forceinline int KeTryAcquireSpinlock(SPINLOCK* sl) {
-    return _InterlockedCompareExchange(&sl->Locked, 1, 0) == 0;
+static __forceinline int KeTryAcquireSpinlock(SPINLOCK* sl, uintptr_t* outFlags) {
+    uintptr_t flags = __readeflags();
+    _disable();
+    if (_InterlockedCompareExchange(&sl->Locked, 1, 0) == 0) {
+        *outFlags = flags;
+        return 1;
+    }
+    __writeeflags(flags);
+    return 0;
 }

code/kernel/ke_switch.asm

@@ -64,9 +64,14 @@ KeSwitchContext ENDP
 ;
 ; We load RCX from the stack (first arg per MS x64), then IRETQ.
 ; -------------------------------------------------------------------------
+EXTERN KeSchedulerPostSwitch : PROC
+
 KeThreadEntry PROC
-    pop     rcx        ; user arg
-    iretq              ; pops RIP, CS, RFLAGS, RSP, SS -> ring 3
+    sub     rsp, 32    ; Reserve shadow space
+    call    KeSchedulerPostSwitch
+    add     rsp, 32
+    pop     rcx        ; load user arg
+    iretq              ; -> ring 3
 KeThreadEntry ENDP
 
 END

code/kernel/ke_thread.c

@@ -7,44 +7,32 @@
 #include <intrin.h>
 
 static uint32_t gNextThreadId = 1;
-
-// ---------------------------------------------------------------------------
-// Initial kernel-side entry point for a new user thread
-//
-// When KeSwitchContext restores a brand-new thread, execution lands here.
-// We set up RFLAGS (enable interrupts) and IRETQ into ring 3.
-// ---------------------------------------------------------------------------
-// Declared in ke_thread_entry.asm - see that file for the implementation.
 extern void KeThreadEntry(void);
 
-// ---------------------------------------------------------------------------
-// Destructor
-// ---------------------------------------------------------------------------
 static void ThreadDestroy(OBJECT* obj) {
     THREAD* thread = CONTAINING_RECORD(obj, THREAD, Header);
 
-    // Detach from owner process.
     if (thread->Owner) {
-        KeAcquireSpinlock(&thread->Owner->HandleLock);
+        uintptr_t flags = KeAcquireSpinlock(&thread->Owner->HandleLock);
         ListRemove(&thread->ProcessLink);
         thread->Owner->ThreadCount--;
-        KeReleaseSpinlock(&thread->Owner->HandleLock);
+        KeReleaseSpinlock(&thread->Owner->HandleLock, flags);
         ObDereferenceObject(&thread->Owner->Header);
         thread->Owner = (PROCESS *)0;
     }
 
-    // Free kernel stack.
     if (thread->KernelStackBase) {
         MmFreePool(thread->KernelStackBase);
         thread->KernelStackBase = (void *)0;
     }
-    // User stack was allocated from user heap - it is up to the process to
-    // track and free it.  For now we leave it (shared heap, no per-process VA).
+    
+    // Assumes UserStackBase was added to THREAD struct in ke_thread.h.
+    if (thread->UserStackBase) {
+        MmFreeUserMemory(thread->UserStackBase, USTACK_SIZE);
+        thread->UserStackBase = (void *)0;
+    }
 }
 
-// ---------------------------------------------------------------------------
-// KeCreateThread
-// ---------------------------------------------------------------------------
 KSTATUS KeCreateThread(PROCESS* owner, uintptr_t entry, uintptr_t arg,
                        THREAD_PRIORITY priority, THREAD **out) {
     if (!owner || !out) return STATUS_INVALID_PARAMETER;
@@ -53,14 +41,14 @@ KSTATUS KeCreateThread(PROCESS* owner, uintptr_t entry, uintptr_t arg,
     THREAD* thread = (THREAD *)ObAllocateObject(ObjectTypeThread, sizeof(THREAD));
     if (!thread) return STATUS_NO_MEMORY;
 
-    thread->Header.Destroy  = ThreadDestroy;
+    thread->Header.Destroy   = ThreadDestroy;
     thread->ThreadId         = _InterlockedExchangeAdd((volatile long *)&gNextThreadId, 1);
     thread->State            = ThreadReady;
     thread->Priority         = priority;
     thread->QuantaConsumed   = 0;
     thread->WaitObject       = (OBJECT *)0;
+    thread->SchedLockFlags   = 0x202ULL;
 
-    // Allocate kernel stack.
     void* kstack = MmAllocatePool(KSTACK_SIZE);
     if (!kstack) {
         ObDereferenceObject(&thread->Header);
@@ -71,87 +59,70 @@ KSTATUS KeCreateThread(PROCESS* owner, uintptr_t entry, uintptr_t arg,
     thread->KernelStackTop  = (uintptr_t)kstack + KSTACK_SIZE;
     thread->TssRsp0         = thread->KernelStackTop;
 
-    // Allocate user stack in the shared user heap.
     void* ustack = MmAllocateUserMemory(USTACK_SIZE);
     if (!ustack) {
         MmFreePool(kstack);
         ObDereferenceObject(&thread->Header);
         return STATUS_NO_MEMORY;
     }
+    thread->UserStackBase = ustack;
     uintptr_t userStackTop = (uintptr_t)ustack + USTACK_SIZE;
 
     thread->UserEntry = entry;
     thread->UserArg   = arg;
 
-    // Set up the initial KCONTEXT so that when KeSwitchContext restores
-    // this thread, execution lands in KeThreadEntry (in ke_switch.asm),
-    // which will IRETQ into ring 3 at UserEntry.
-    // The KCONTEXT sits at the top of the kernel stack.
     uintptr_t* ksp = (uintptr_t *)thread->KernelStackTop;
-
-    // Push user RSP so KeThreadEntry can find it.
     *(--ksp) = userStackTop;
+    *(--ksp) = 0x23ULL;          
+    *(--ksp) = userStackTop;     
+    *(--ksp) = 0x202ULL;         
+    *(--ksp) = 0x1BULL;          
+    *(--ksp) = entry;            
+    *(--ksp) = arg;              
 
-    // Push the IRETQ frame: RIP, CS (ring3), RFLAGS, RSP, SS (ring3).
-    // Segment selector values: 0x1B = ring-3 code, 0x23 = ring-3 data.
-    *(--ksp) = 0x23ULL;          // SS
-    *(--ksp) = userStackTop;     // RSP (already set above but IRETQ needs it)
-    *(--ksp) = 0x202ULL;         // RFLAGS: IF=1, reserved bit 1
-    *(--ksp) = 0x1BULL;          // CS
-    *(--ksp) = entry;            // RIP
-    // RCX = arg (first argument per MS x64 ABI).
-    *(--ksp) = arg;              // RCX placeholder - KeThreadEntry loads it
-
-    // Now build the KCONTEXT that KeSwitchContext will restore.
-    // Rip points to KeThreadEntry; all other regs zero; RSP = ksp.
     ksp -= sizeof(KCONTEXT) / sizeof(uintptr_t);
     KCONTEXT* ctx = (KCONTEXT *)ksp;
     memset(ctx, 0, sizeof(KCONTEXT));
     ctx->Rip = (uint64_t)KeThreadEntry;
     thread->SavedContext = ctx;
 
-    // Link into the owner process.
     ObReferenceObject(&owner->Header);
     thread->Owner = owner;
-    KeAcquireSpinlock(&owner->HandleLock);
+    
+    uintptr_t flags = KeAcquireSpinlock(&owner->HandleLock);
     ListInsertTail(&owner->ThreadList, &thread->ProcessLink);
     owner->ThreadCount++;
-    KeReleaseSpinlock(&owner->HandleLock);
+    KeReleaseSpinlock(&owner->HandleLock, flags);
 
-    // Hand the thread to the scheduler.
     KeReadyThread(thread);
-
     *out = thread;
     return STATUS_SUCCESS;
 }
 
-// ---------------------------------------------------------------------------
-// KeExitThread
-// ---------------------------------------------------------------------------
 void KeExitThread(THREAD* thread, int code) {
     (void)code;
     if (!thread) return;
 
     thread->State = ThreadDead;
-    KeUnreadyThread(thread);
-    ObDereferenceObject(&thread->Header);
 
-    // Yield - the scheduler will never pick this thread again.
     KeYield();
 }
 
-// ---------------------------------------------------------------------------
-// Block / unblock
-// ---------------------------------------------------------------------------
 void KeBlockThread(THREAD* thread, OBJECT* waitObject) {
     thread->State      = ThreadWaiting;
     thread->WaitObject = waitObject;
-    KeUnreadyThread(thread);
+
     KeYield();
 }
 
 void KeUnblockThread(THREAD* thread) {
     thread->WaitObject = (OBJECT *)0;
     thread->State      = ThreadReady;
+    
+    if (thread->Priority < PriorityHigh) {
+        thread->Priority = (THREAD_PRIORITY)(thread->Priority + 1);
+        thread->QuantaConsumed = 0;
+    }
+    
     KeReadyThread(thread);
 }

code/kernel/ke_thread.h

@@ -61,6 +61,9 @@ typedef struct THREAD {
     // Ring-3 entry point and argument for newly created threads.
     uintptr_t       UserEntry;
     uintptr_t       UserArg;
+
+    uintptr_t SchedLockFlags; // Stores RFLAGS while thread is context switched out
+    void* UserStackBase;      // Tracks user stack allocation to prevent memory leaks
 } THREAD;
 
 KSTATUS KeCreateThread(PROCESS* owner, uintptr_t entry, uintptr_t arg,

code/kernel/mm_phys.c

@@ -36,11 +36,11 @@ static FRAME_STACK gFrameStack;
 
 // Push a physical frame address onto the stack.
 static void PushFrame(PHYSICAL_ADDRESS frame) {
-    KeAcquireSpinlock(&gFrameStack.Lock);
+    uintptr_t flags = KeAcquireSpinlock(&gFrameStack.Lock);
     if (gFrameStack.Top < gFrameStack.Capacity) {
         gFrameStack.Stack[gFrameStack.Top++] = frame;
     }
-    KeReleaseSpinlock(&gFrameStack.Lock);
+    KeReleaseSpinlock(&gFrameStack.Lock, flags);
 }
 
 // ---------------------------------------------------------------------------
@@ -104,32 +104,32 @@ void MmInitializePhysical(const MEMORY_MAP* map, uint64_t physicalWindowBase) {
 // Public API
 // ---------------------------------------------------------------------------
 PHYSICAL_ADDRESS MmAllocateFrame(void) {
-    KeAcquireSpinlock(&gFrameStack.Lock);
+    uintptr_t flags = KeAcquireSpinlock(&gFrameStack.Lock);
     if (gFrameStack.Top == 0) {
-        KeReleaseSpinlock(&gFrameStack.Lock);
+        KeReleaseSpinlock(&gFrameStack.Lock, flags);
         return (PHYSICAL_ADDRESS)0;
     }
     PHYSICAL_ADDRESS frame = gFrameStack.Stack[--gFrameStack.Top];
-    KeReleaseSpinlock(&gFrameStack.Lock);
+    KeReleaseSpinlock(&gFrameStack.Lock, flags);
     return frame;
 }
 
 void MmFreeFrame(PHYSICAL_ADDRESS frame) {
     if (!frame || (frame & (PAGE_SIZE - 1))) return;
-    KeAcquireSpinlock(&gFrameStack.Lock);
+    uintptr_t flags = KeAcquireSpinlock(&gFrameStack.Lock);
     if (gFrameStack.Top < gFrameStack.Capacity)
         gFrameStack.Stack[gFrameStack.Top++] = frame;
     // else: stack full — leak rather than corrupt
-    KeReleaseSpinlock(&gFrameStack.Lock);
+    KeReleaseSpinlock(&gFrameStack.Lock, flags);
 }
 
 PHYSICAL_ADDRESS MmAllocateContiguous(size_t count) {
     if (!count) return (PHYSICAL_ADDRESS)0;
 
-    KeAcquireSpinlock(&gFrameStack.Lock);
+    uintptr_t flags = KeAcquireSpinlock(&gFrameStack.Lock);
 
     if (gFrameStack.Top < count) {
-        KeReleaseSpinlock(&gFrameStack.Lock);
+        KeReleaseSpinlock(&gFrameStack.Lock, flags);
         return (PHYSICAL_ADDRESS)0;
     }
 
@@ -152,7 +152,7 @@ PHYSICAL_ADDRESS MmAllocateContiguous(size_t count) {
     }
 
     if (run == (size_t)-1) {
-        KeReleaseSpinlock(&gFrameStack.Lock);
+        KeReleaseSpinlock(&gFrameStack.Lock, flags);
         return (PHYSICAL_ADDRESS)0;
     }
 
@@ -164,7 +164,7 @@ PHYSICAL_ADDRESS MmAllocateContiguous(size_t count) {
         gFrameStack.Stack[run + i] = gFrameStack.Stack[run + count + i];
     gFrameStack.Top -= count;
 
-    KeReleaseSpinlock(&gFrameStack.Lock);
+    KeReleaseSpinlock(&gFrameStack.Lock, flags);
     return base;
 }
 

code/kernel/mm_virt.c

@@ -243,7 +243,7 @@ static void* HeapAlloc(HEAP* h, size_t size) {
     if (!size) return (void *)0;
     size = (size + 7) & ~7ULL;   // 8-byte align
 
-    KeAcquireSpinlock(&h->Lock);
+    uintptr_t flags = KeAcquireSpinlock(&h->Lock);
 
     // Best-fit search.
     BLOCK_HDR* best = (BLOCK_HDR *)0;
@@ -256,14 +256,14 @@ static void* HeapAlloc(HEAP* h, size_t size) {
 
     if (!best) {
         if (!HeapGrow(h, size + OVERHEAD)) {
-            KeReleaseSpinlock(&h->Lock);
+            KeReleaseSpinlock(&h->Lock, flags);
             return (void *)0;
         }
         // Re-search; HeapGrow inserted at the front.
         best = h->FreeList;
         while (best && best->Size < size) best = best->NextFree;
         if (!best) {
-            KeReleaseSpinlock(&h->Lock);
+            KeReleaseSpinlock(&h->Lock, flags);
             return (void *)0;
         }
     }
@@ -292,7 +292,7 @@ static void* HeapAlloc(HEAP* h, size_t size) {
     HdrToFtr(best)->Magic = BLOCK_MAGIC;
     HdrToFtr(best)->Size  = best->Size;
 
-    KeReleaseSpinlock(&h->Lock);
+    KeReleaseSpinlock(&h->Lock, flags);
     return (char *)best + HDR_SIZE;
 }
 
@@ -301,7 +301,7 @@ static void HeapFree(HEAP* h, void* ptr) {
     BLOCK_HDR* blk = (BLOCK_HDR *)((char *)ptr - HDR_SIZE);
     if (blk->Magic != BLOCK_MAGIC || blk->Free) return;   // double-free / corrupt
 
-    KeAcquireSpinlock(&h->Lock);
+    uintptr_t flags = KeAcquireSpinlock(&h->Lock);
 
     blk->Free = 1;
 
@@ -338,7 +338,7 @@ static void HeapFree(HEAP* h, void* ptr) {
     HdrToFtr(blk)->Free  = 1;
     HdrToFtr(blk)->Magic = BLOCK_MAGIC;
 
-    KeReleaseSpinlock(&h->Lock);
+    KeReleaseSpinlock(&h->Lock, flags);
 }
 
 static void* HeapRealloc(HEAP* h, void* ptr, size_t new_size) {

rund.bat

@@ -1 +1 @@
-@start qemu-system-x86_64 -drive if=pflash,format=raw,readonly=on,file=OVMF\OVMF_CODE_4M.fd -drive if=pflash,format=raw,file=OVMF\OVMF_VARS_4M.fd -device ahci,id=ahci -drive format=raw,file=\\.\PhysicalDrive7,if=none,id=disk0 -device ide-hd,bus=ahci.0,drive=disk0 -m 4G -serial stdio -d in_asm,cpu_reset,int -D qemu.log -no-reboot -no-shutdown
+@start qemu-system-x86_64 -drive if=pflash,format=raw,readonly=on,file=OVMF\OVMF_CODE_4M.fd -drive if=pflash,format=raw,file=OVMF\OVMF_VARS_4M_d.fd -device ahci,id=ahci -drive format=raw,file=\\.\PhysicalDrive7,if=none,id=disk0 -device ide-hd,bus=ahci.0,drive=disk0 -m 4G -serial stdio -d in_asm,cpu_reset,int -D qemu.log -no-reboot -no-shutdown