13 files changed, 209 insertions, 168 deletions

diff --git a/src/core/hle/kernel/address_arbiter.cpp b/src/core/hle/kernel/address_arbiter.cpp
index acdbc92b3..38705e3cd 100644
--- a/src/core/hle/kernel/address_arbiter.cpp
+++ b/src/core/hle/kernel/address_arbiter.cpp
@@ -62,7 +62,8 @@ ResultCode ArbitrateAddress(Handle handle, ArbitrationType type, u32 address, s3
 /// Create an address arbiter
 AddressArbiter* CreateAddressArbiter(Handle& handle, const std::string& name) {
     AddressArbiter* address_arbiter = new AddressArbiter;
-    handle = Kernel::g_handle_table.Create(address_arbiter);
+    // TOOD(yuriks): Fix error reporting
+    handle = Kernel::g_handle_table.Create(address_arbiter).ValueOr(INVALID_HANDLE);
     address_arbiter->name = name;
     return address_arbiter;
 }
diff --git a/src/core/hle/kernel/event.cpp b/src/core/hle/kernel/event.cpp
index 6a0e294cb..e43c3ee4e 100644
--- a/src/core/hle/kernel/event.cpp
+++ b/src/core/hle/kernel/event.cpp
@@ -129,7 +129,8 @@ ResultCode ClearEvent(Handle handle) {
 Event* CreateEvent(Handle& handle, const ResetType reset_type, const std::string& name) {
     Event* evt = new Event;
 
-    handle = Kernel::g_handle_table.Create(evt);
+    // TOOD(yuriks): Fix error reporting
+    handle = Kernel::g_handle_table.Create(evt).ValueOr(INVALID_HANDLE);
 
     evt->locked = true;
     evt->permanent_locked = false;
diff --git a/src/core/hle/kernel/kernel.cpp b/src/core/hle/kernel/kernel.cpp
index e8bf83a44..e59ed1b57 100644
--- a/src/core/hle/kernel/kernel.cpp
+++ b/src/core/hle/kernel/kernel.cpp
@@ -17,73 +17,89 @@ HandleTable g_handle_table;
 u64 g_program_id = 0;
 
 HandleTable::HandleTable() {
-    next_id = INITIAL_NEXT_ID;
+    next_generation = 1;
+    Clear();
 }
 
-Handle HandleTable::Create(Object* obj, int range_bottom, int range_top) {
-    if (range_top > MAX_COUNT) {
-        range_top = MAX_COUNT;
-    }
-    if (next_id >= range_bottom && next_id < range_top) {
-        range_bottom = next_id++;
-    }
-    for (int i = range_bottom; i < range_top; i++) {
-        if (!occupied[i]) {
-            occupied[i] = true;
-            pool[i] = obj;
-            pool[i]->handle = i + HANDLE_OFFSET;
-            return i + HANDLE_OFFSET;
-        }
+ResultVal<Handle> HandleTable::Create(Object* obj) {
+    _dbg_assert_(Kernel, obj != nullptr);
+
+    u16 slot = next_free_slot;
+    if (slot >= generations.size()) {
+        LOG_ERROR(Kernel, "Unable to allocate Handle, too many slots in use.");
+        return ERR_OUT_OF_HANDLES;
     }
-    LOG_ERROR(Kernel, "Unable to allocate kernel object, too many objects slots in use.");
-    return 0;
-}
+    next_free_slot = generations[slot];
 
-bool HandleTable::IsValid(Handle handle) const {
-    int index = handle - HANDLE_OFFSET;
-    if (index < 0)
-        return false;
-    if (index >= MAX_COUNT)
-        return false;
+    u16 generation = next_generation++;
 
-    return occupied[index];
+    // Overflow count so it fits in the 15 bits dedicated to the generation in the handle.
+    // CTR-OS doesn't use generation 0, so skip straight to 1.
+    if (next_generation >= (1 << 15)) next_generation = 1;
+
+    generations[slot] = generation;
+    intrusive_ptr_add_ref(obj);
+    objects[slot] = obj;
+
+    Handle handle = generation | (slot << 15);
+    obj->handle = handle;
+    return MakeResult<Handle>(handle);
 }
 
-void HandleTable::Clear() {
-    for (int i = 0; i < MAX_COUNT; i++) {
-        //brutally clear everything, no validation
-        if (occupied[i])
-            delete pool[i];
-        occupied[i] = false;
+ResultVal<Handle> HandleTable::Duplicate(Handle handle) {
+    Object* object = GetGeneric(handle);
+    if (object == nullptr) {
+        LOG_ERROR(Kernel, "Tried to duplicate invalid handle: %08X", handle);
+        return ERR_INVALID_HANDLE;
     }
-    pool.fill(nullptr);
-    next_id = INITIAL_NEXT_ID;
+    return Create(object);
 }
 
-Object* &HandleTable::operator [](Handle handle)
-{
-    _dbg_assert_msg_(Kernel, IsValid(handle), "GRABBING UNALLOCED KERNEL OBJ");
-    return pool[handle - HANDLE_OFFSET];
+ResultCode HandleTable::Close(Handle handle) {
+    if (!IsValid(handle))
+        return ERR_INVALID_HANDLE;
+
+    size_t slot = GetSlot(handle);
+    u16 generation = GetGeneration(handle);
+
+    intrusive_ptr_release(objects[slot]);
+    objects[slot] = nullptr;
+
+    generations[generation] = next_free_slot;
+    next_free_slot = slot;
+    return RESULT_SUCCESS;
 }
 
-void HandleTable::List() {
-    for (int i = 0; i < MAX_COUNT; i++) {
-        if (occupied[i]) {
-            if (pool[i]) {
-                LOG_DEBUG(Kernel, "KO %i: %s \"%s\"", i + HANDLE_OFFSET, pool[i]->GetTypeName().c_str(),
-                    pool[i]->GetName().c_str());
-            }
-        }
-    }
+bool HandleTable::IsValid(Handle handle) const {
+    size_t slot = GetSlot(handle);
+    u16 generation = GetGeneration(handle);
+
+    return slot < MAX_COUNT && objects[slot] != nullptr && generations[slot] == generation;
 }
 
-int HandleTable::GetCount() const {
-    return std::count(occupied.begin(), occupied.end(), true);
+Object* HandleTable::GetGeneric(Handle handle) const {
+    if (handle == CurrentThread) {
+        // TODO(yuriks) Directly return the pointer once this is possible.
+        handle = GetCurrentThreadHandle();
+    } else if (handle == CurrentProcess) {
+        LOG_ERROR(Kernel, "Current process (%08X) pseudo-handle not supported", CurrentProcess);
+        return nullptr;
+    }
+
+    if (!IsValid(handle)) {
+        return nullptr;
+    }
+    return objects[GetSlot(handle)];
 }
 
-Object* HandleTable::CreateByIDType(int type) {
-    LOG_ERROR(Kernel, "Unimplemented: %d.", type);
-    return nullptr;
+void HandleTable::Clear() {
+    for (size_t i = 0; i < MAX_COUNT; ++i) {
+        generations[i] = i + 1;
+        if (objects[i] != nullptr)
+            intrusive_ptr_release(objects[i]);
+        objects[i] = nullptr;
+    }
+    next_free_slot = 0;
 }
 
 /// Initialize the kernel
diff --git a/src/core/hle/kernel/kernel.h b/src/core/hle/kernel/kernel.h
index 27c406ad4..7f86fd07d 100644
--- a/src/core/hle/kernel/kernel.h
+++ b/src/core/hle/kernel/kernel.h
@@ -12,13 +12,17 @@
 typedef u32 Handle;
 typedef s32 Result;
 
+const Handle INVALID_HANDLE = 0;
+
 namespace Kernel {
 
-// From kernel.h. Declarations duplicated here to avoid a circular header dependency.
-class Thread;
-Thread* GetCurrentThread();
+// TODO: Verify code
+const ResultCode ERR_OUT_OF_HANDLES(ErrorDescription::OutOfMemory, ErrorModule::Kernel,
+        ErrorSummary::OutOfResource, ErrorLevel::Temporary);
+// TOOD: Verify code
+const ResultCode ERR_INVALID_HANDLE = InvalidHandle(ErrorModule::Kernel);
 
-enum KernelHandle {
+enum KernelHandle : Handle {
     CurrentThread   = 0xFFFF8000,
     CurrentProcess  = 0xFFFF8001,
 };
@@ -61,103 +65,127 @@ public:
         LOG_ERROR(Kernel, "(UNIMPLEMENTED)");
         return UnimplementedFunction(ErrorModule::Kernel);
     }
-};
 
-class HandleTable : NonCopyable {
-public:
-    HandleTable();
-    ~HandleTable() {}
+private:
+    friend void intrusive_ptr_add_ref(Object*);
+    friend void intrusive_ptr_release(Object*);
 
-    // Allocates a handle within the range and inserts the object into the map.
-    Handle Create(Object* obj, int range_bottom=INITIAL_NEXT_ID, int range_top=0x7FFFFFFF);
+    unsigned int ref_count = 0;
+};
 
-    static Object* CreateByIDType(int type);
+// Special functions that will later be used by boost::instrusive_ptr to do automatic ref-counting
+inline void intrusive_ptr_add_ref(Object* object) {
+    ++object->ref_count;
+}
 
-    template <class T>
-    void Destroy(Handle handle) {
-        if (Get<T>(handle)) {
-            occupied[handle - HANDLE_OFFSET] = false;
-            delete pool[handle - HANDLE_OFFSET];
-        }
+inline void intrusive_ptr_release(Object* object) {
+    if (--object->ref_count == 0) {
+        delete object;
     }
+}
 
-    bool IsValid(Handle handle) const;
+/**
+ * This class allows the creation of Handles, which are references to objects that can be tested
+ * for validity and looked up. Here they are used to pass references to kernel objects to/from the
+ * emulated process. it has been designed so that it follows the same handle format and has
+ * approximately the same restrictions as the handle manager in the CTR-OS.
+ *
+ * Handles contain two sub-fields: a slot index (bits 31:15) and a generation value (bits 14:0).
+ * The slot index is used to index into the arrays in this class to access the data corresponding
+ * to the Handle.
+ *
+ * To prevent accidental use of a freed Handle whose slot has already been reused, a global counter
+ * is kept and incremented every time a Handle is created. This is the Handle's "generation". The
+ * value of the counter is stored into the Handle as well as in the handle table (in the
+ * "generations" array). When looking up a handle, the Handle's generation must match with the
+ * value stored on the class, otherwise the Handle is considered invalid.
+ *
+ * To find free slots when allocating a Handle without needing to scan the entire object array, the
+ * generations field of unallocated slots is re-purposed as a linked list of indices to free slots.
+ * When a Handle is created, an index is popped off the list and used for the new Handle. When it
+ * is destroyed, it is again pushed onto the list to be re-used by the next allocation. It is
+ * likely that this allocation strategy differs from the one used in CTR-OS, but this hasn't been
+ * verified and isn't likely to cause any problems.
+ */
+class HandleTable final : NonCopyable {
+public:
+    HandleTable();
 
-    template <class T>
-    T* Get(Handle handle) {
-        if (handle == CurrentThread) {
-            return reinterpret_cast<T*>(GetCurrentThread());
-        }
+    /**
+     * Allocates a handle for the given object.
+     * @return The created Handle or one of the following errors:
+     *           - `ERR_OUT_OF_HANDLES`: the maximum number of handles has been exceeded.
+     */
+    ResultVal<Handle> Create(Object* obj);
 
-        if (handle < HANDLE_OFFSET || handle >= HANDLE_OFFSET + MAX_COUNT || !occupied[handle - HANDLE_OFFSET]) {
-            if (handle != 0) {
-                LOG_ERROR(Kernel, "Bad object handle %08x", handle);
-            }
-            return nullptr;
-        } else {
-            Object* t = pool[handle - HANDLE_OFFSET];
-            if (t->GetHandleType() != T::HANDLE_TYPE) {
-                LOG_ERROR(Kernel, "Wrong object type for %08x", handle);
-                return nullptr;
-            }
-            return static_cast<T*>(t);
-        }
-    }
+    /**
+     * Returns a new handle that points to the same object as the passed in handle.
+     * @return The duplicated Handle or one of the following errors:
+     *           - `ERR_INVALID_HANDLE`: an invalid handle was passed in.
+     *           - Any errors returned by `Create()`.
+     */
+    ResultVal<Handle> Duplicate(Handle handle);
 
-    // ONLY use this when you know the handle is valid.
-    template <class T>
-    T *GetFast(Handle handle) {
-        if (handle == CurrentThread) {
-            return reinterpret_cast<T*>(GetCurrentThread());
-        }
+    /**
+     * Closes a handle, removing it from the table and decreasing the object's ref-count.
+     * @return `RESULT_SUCCESS` or one of the following errors:
+     *           - `ERR_INVALID_HANDLE`: an invalid handle was passed in.
+     */
+    ResultCode Close(Handle handle);
 
-        const Handle realHandle = handle - HANDLE_OFFSET;
-        _dbg_assert_(Kernel, realHandle >= 0 && realHandle < MAX_COUNT && occupied[realHandle]);
-        return static_cast<T*>(pool[realHandle]);
-    }
+    /// Checks if a handle is valid and points to an existing object.
+    bool IsValid(Handle handle) const;
 
-    template <class T, typename ArgT>
-    void Iterate(bool func(T*, ArgT), ArgT arg) {
-        int type = T::GetStaticIDType();
-        for (int i = 0; i < MAX_COUNT; i++)
-        {
-            if (!occupied[i])
-                continue;
-            T* t = static_cast<T*>(pool[i]);
-            if (t->GetIDType() == type) {
-                if (!func(t, arg))
-                    break;
-            }
-        }
-    }
+    /**
+     * Looks up a handle.
+     * @returns Pointer to the looked-up object, or `nullptr` if the handle is not valid.
+     */
+    Object* GetGeneric(Handle handle) const;
 
-    bool GetIDType(Handle handle, HandleType* type) const {
-        if ((handle < HANDLE_OFFSET) || (handle >= HANDLE_OFFSET + MAX_COUNT) ||
-                !occupied[handle - HANDLE_OFFSET]) {
-            LOG_ERROR(Kernel, "Bad object handle %08X", handle);
-            return false;
+    /**
+     * Looks up a handle while verifying its type.
+     * @returns Pointer to the looked-up object, or `nullptr` if the handle is not valid or its
+     *          type differs from the handle type `T::HANDLE_TYPE`.
+     */
+    template <class T>
+    T* Get(Handle handle) const {
+        Object* object = GetGeneric(handle);
+        if (object != nullptr && object->GetHandleType() == T::HANDLE_TYPE) {
+            return static_cast<T*>(object);
         }
-        Object* t = pool[handle - HANDLE_OFFSET];
-        *type = t->GetHandleType();
-        return true;
+        return nullptr;
     }
 
-    Object* &operator [](Handle handle);
-    void List();
+    /// Closes all handles held in this table.
     void Clear();
-    int GetCount() const;
 
 private:
+    /**
+     * This is the maximum limit of handles allowed per process in CTR-OS. It can be further
+     * reduced by ExHeader values, but this is not emulated here.
+     */
+    static const size_t MAX_COUNT = 4096;
+
+    static size_t GetSlot(Handle handle)    { return handle >> 15; }
+    static u16 GetGeneration(Handle handle) { return handle & 0x7FFF; }
+
+    /// Stores the Object referenced by the handle or null if the slot is empty.
+    std::array<Object*, MAX_COUNT> objects;
 
-    enum {
-        MAX_COUNT       = 0x1000,
-        HANDLE_OFFSET   = 0x100,
-        INITIAL_NEXT_ID = 0x10,
-    };
+    /**
+     * The value of `next_generation` when the handle was created, used to check for validity. For
+     * empty slots, contains the index of the next free slot in the list.
+     */
+    std::array<u16, MAX_COUNT> generations;
+
+    /**
+     * Global counter of the number of created handles. Stored in `generations` when a handle is
+     * created, and wraps around to 1 when it hits 0x8000.
+     */
+    u16 next_generation;
 
-    std::array<Object*, MAX_COUNT> pool;
-    std::array<bool, MAX_COUNT> occupied;
-    int next_id;
+    /// Head of the free slots linked list.
+    u16 next_free_slot;
 };
 
 extern HandleTable g_handle_table;
diff --git a/src/core/hle/kernel/mutex.cpp b/src/core/hle/kernel/mutex.cpp
index 08462376d..558068c79 100644
--- a/src/core/hle/kernel/mutex.cpp
+++ b/src/core/hle/kernel/mutex.cpp
@@ -87,7 +87,7 @@ void ReleaseThreadMutexes(Handle thread) {
     
     // Release every mutex that the thread holds, and resume execution on the waiting threads
     for (MutexMap::iterator iter = locked.first; iter != locked.second; ++iter) {
-        Mutex* mutex = g_handle_table.GetFast<Mutex>(iter->second);
+        Mutex* mutex = g_handle_table.Get<Mutex>(iter->second);
         ResumeWaitingThread(mutex);
     }
 
@@ -136,7 +136,8 @@ ResultCode ReleaseMutex(Handle handle) {
  */
 Mutex* CreateMutex(Handle& handle, bool initial_locked, const std::string& name) {
     Mutex* mutex = new Mutex;
-    handle = Kernel::g_handle_table.Create(mutex);
+    // TODO(yuriks): Fix error reporting
+    handle = Kernel::g_handle_table.Create(mutex).ValueOr(INVALID_HANDLE);
 
     mutex->locked = mutex->initial_locked = initial_locked;
     mutex->name = name;
diff --git a/src/core/hle/kernel/semaphore.cpp b/src/core/hle/kernel/semaphore.cpp
index 1dee15f10..6bc8066a6 100644
--- a/src/core/hle/kernel/semaphore.cpp
+++ b/src/core/hle/kernel/semaphore.cpp
@@ -57,7 +57,8 @@ ResultCode CreateSemaphore(Handle* handle, s32 initial_count,
                           ErrorSummary::WrongArgument, ErrorLevel::Permanent);
 
     Semaphore* semaphore = new Semaphore;
-    *handle = g_handle_table.Create(semaphore);
+    // TOOD(yuriks): Fix error reporting
+    *handle = g_handle_table.Create(semaphore).ValueOr(INVALID_HANDLE);
 
     // When the semaphore is created, some slots are reserved for other threads,
     // and the rest is reserved for the caller thread
diff --git a/src/core/hle/kernel/shared_memory.cpp b/src/core/hle/kernel/shared_memory.cpp
index bd9d947a3..cea1f6fa1 100644
--- a/src/core/hle/kernel/shared_memory.cpp
+++ b/src/core/hle/kernel/shared_memory.cpp
@@ -32,7 +32,8 @@ public:
  */
 SharedMemory* CreateSharedMemory(Handle& handle, const std::string& name) {
     SharedMemory* shared_memory = new SharedMemory;
-    handle = Kernel::g_handle_table.Create(shared_memory);
+    // TOOD(yuriks): Fix error reporting
+    handle = Kernel::g_handle_table.Create(shared_memory).ValueOr(INVALID_HANDLE);
     shared_memory->name = name;
     return shared_memory;
 }
diff --git a/src/core/hle/kernel/thread.cpp b/src/core/hle/kernel/thread.cpp
index 2739bdd52..872df2d14 100644
--- a/src/core/hle/kernel/thread.cpp
+++ b/src/core/hle/kernel/thread.cpp
@@ -341,7 +341,8 @@ Thread* CreateThread(Handle& handle, const char* name, u32 entry_point, s32 prio
 
     Thread* thread = new Thread;
 
-    handle = Kernel::g_handle_table.Create(thread);
+    // TOOD(yuriks): Fix error reporting
+    handle = Kernel::g_handle_table.Create(thread).ValueOr(INVALID_HANDLE);
 
     thread_queue.push_back(handle);
     thread_ready_queue.prepare(priority);
diff --git a/src/core/hle/kernel/thread.h b/src/core/hle/kernel/thread.h
index 9396b6b26..0e1397cd9 100644
--- a/src/core/hle/kernel/thread.h
+++ b/src/core/hle/kernel/thread.h
@@ -77,9 +77,6 @@ Handle ArbitrateHighestPriorityThread(u32 arbiter, u32 address);
 /// Arbitrate all threads currently waiting...
 void ArbitrateAllThreads(u32 arbiter, u32 address);
 
-/// Gets the current thread
-Thread* GetCurrentThread();
-
 /// Gets the current thread handle
 Handle GetCurrentThreadHandle();
 
diff --git a/src/core/hle/service/fs/archive.cpp b/src/core/hle/service/fs/archive.cpp
index 5746b58e5..487bf3aa7 100644
--- a/src/core/hle/service/fs/archive.cpp
+++ b/src/core/hle/service/fs/archive.cpp
@@ -133,7 +133,7 @@ public:
         case FileCommand::Close:
         {
             LOG_TRACE(Service_FS, "Close %s %s", GetTypeName().c_str(), GetName().c_str());
-            Kernel::g_handle_table.Destroy<File>(GetHandle());
+            backend->Close();
             break;
         }
 
@@ -189,7 +189,7 @@ public:
         case DirectoryCommand::Close:
         {
             LOG_TRACE(Service_FS, "Close %s %s", GetTypeName().c_str(), GetName().c_str());
-            Kernel::g_handle_table.Destroy<Directory>(GetHandle());
+            backend->Close();
             break;
         }
 
@@ -283,7 +283,8 @@ ResultVal<Handle> OpenFileFromArchive(ArchiveHandle archive_handle, const FileSy
     }
 
     auto file = Common::make_unique<File>(std::move(backend), path);
-    Handle handle = Kernel::g_handle_table.Create(file.release());
+    // TOOD(yuriks): Fix error reporting
+    Handle handle = Kernel::g_handle_table.Create(file.release()).ValueOr(INVALID_HANDLE);
     return MakeResult<Handle>(handle);
 }
 
@@ -388,7 +389,8 @@ ResultVal<Handle> OpenDirectoryFromArchive(ArchiveHandle archive_handle, const F
     }
 
     auto directory = Common::make_unique<Directory>(std::move(backend), path);
-    Handle handle = Kernel::g_handle_table.Create(directory.release());
+    // TOOD(yuriks): Fix error reporting
+    Handle handle = Kernel::g_handle_table.Create(directory.release()).ValueOr(INVALID_HANDLE);
     return MakeResult<Handle>(handle);
 }
 
diff --git a/src/core/hle/service/service.cpp b/src/core/hle/service/service.cpp
index e9a7973b3..0f3cc2aa8 100644
--- a/src/core/hle/service/service.cpp
+++ b/src/core/hle/service/service.cpp
@@ -56,7 +56,8 @@ Manager::~Manager() {
 
 /// Add a service to the manager (does not create it though)
 void Manager::AddService(Interface* service) {
-    m_port_map[service->GetPortName()] = Kernel::g_handle_table.Create(service);
+    // TOOD(yuriks): Fix error reporting
+    m_port_map[service->GetPortName()] = Kernel::g_handle_table.Create(service).ValueOr(INVALID_HANDLE);
     m_services.push_back(service);
 }
 
diff --git a/src/core/hle/service/service.h b/src/core/hle/service/service.h
index 9d5828fd0..28b4ccd17 100644
--- a/src/core/hle/service/service.h
+++ b/src/core/hle/service/service.h
@@ -54,7 +54,8 @@ public:
 
     /// Allocates a new handle for the service
     Handle CreateHandle(Kernel::Object *obj) {
-        Handle handle = Kernel::g_handle_table.Create(obj);
+        // TODO(yuriks): Fix error reporting
+        Handle handle = Kernel::g_handle_table.Create(obj).ValueOr(INVALID_HANDLE);
         m_handles.push_back(handle);
         return handle;
     }
@@ -62,7 +63,7 @@ public:
     /// Frees a handle from the service
     template <class T>
     void DeleteHandle(const Handle handle) {
-        Kernel::g_handle_table.Destroy<T>(handle);
+        Kernel::g_handle_table.Close(handle);
         m_handles.erase(std::remove(m_handles.begin(), m_handles.end(), handle), m_handles.end());
     }
 
diff --git a/src/core/hle/svc.cpp b/src/core/hle/svc.cpp
index a48ac09a3..25944fc68 100644
--- a/src/core/hle/svc.cpp
+++ b/src/core/hle/svc.cpp
@@ -119,11 +119,9 @@ static Result WaitSynchronization1(Handle handle, s64 nano_seconds) {
     // TODO(bunnei): Do something with nano_seconds, currently ignoring this
     bool wait_infinite = (nano_seconds == -1); // Used to wait until a thread has terminated
 
-    if (!Kernel::g_handle_table.IsValid(handle)) {
+    Kernel::Object* object = Kernel::g_handle_table.GetGeneric(handle);
+    if (object == nullptr)
         return InvalidHandle(ErrorModule::Kernel).raw;
-    }
-    Kernel::Object* object = Kernel::g_handle_table.GetFast<Kernel::Object>(handle);
-    _dbg_assert_(Kernel, object != nullptr);
 
     LOG_TRACE(Kernel_SVC, "called handle=0x%08X(%s:%s), nanoseconds=%lld", handle, object->GetTypeName().c_str(),
             object->GetName().c_str(), nano_seconds);
@@ -150,10 +148,9 @@ static Result WaitSynchronizationN(s32* out, Handle* handles, s32 handle_count,
 
     // Iterate through each handle, synchronize kernel object
     for (s32 i = 0; i < handle_count; i++) {
-        if (!Kernel::g_handle_table.IsValid(handles[i])) {
+        Kernel::Object* object = Kernel::g_handle_table.GetGeneric(handles[i]);
+        if (object == nullptr)
             return InvalidHandle(ErrorModule::Kernel).raw;
-        }
-        Kernel::Object* object = Kernel::g_handle_table.GetFast<Kernel::Object>(handles[i]);
 
         LOG_TRACE(Kernel_SVC, "\thandle[%d] = 0x%08X(%s:%s)", i, handles[i], object->GetTypeName().c_str(),
             object->GetName().c_str());
@@ -321,19 +318,12 @@ static Result CreateEvent(Handle* evt, u32 reset_type) {
 
 /// Duplicates a kernel handle
 static Result DuplicateHandle(Handle* out, Handle handle) {
-    LOG_WARNING(Kernel_SVC, "(STUBBED) called handle=0x%08X", handle);
-
-    // Translate kernel handles -> real handles
-    if (handle == Kernel::CurrentThread) {
-        handle = Kernel::GetCurrentThreadHandle();
+    ResultVal<Handle> out_h = Kernel::g_handle_table.Duplicate(handle);
+    if (out_h.Succeeded()) {
+        *out = *out_h;
+        LOG_TRACE(Kernel_SVC, "duplicated 0x%08X to 0x%08X", handle, *out);
     }
-    _assert_msg_(KERNEL, (handle != Kernel::CurrentProcess),
-        "(UNIMPLEMENTED) process handle duplication!");
-
-    // TODO(bunnei): FixMe - This is a hack to return the handle that we were asked to duplicate.
-    *out = handle;
-
-    return 0;
+    return out_h.Code().raw;
 }
 
 /// Signals an event