HLE: Revamp error handling throrough the HLE code

All service calls in the CTR OS return result codes indicating the
success or failure of the call. Previous to this commit, Citra's HLE
emulation of services and the kernel universally either ignored errors
or returned dummy -1 error codes.

This commit makes an initial effort to provide an infrastructure for
error reporting and propagation which can be use going forward to make
HLE calls accurately return errors as the original system. A few parts
of the code have been updated to use the new system where applicable.

One part of this effort is the definition of the `ResultCode` type,
which provides facilities for constructing and parsing error codes in
the structured format used by the CTR.

The `ResultVal` type builds on `ResultCode` by providing a container for
values returned by function that can report errors. It enforces that
correct error checking will be done on function returns by preventing
the use of the return value if the function returned an error code.

Currently this change is mostly internal since errors are still
suppressed on the ARM<->HLE border, as a temporary compatibility hack.
As functionality is implemented and tested this hack can be eventually
removed.

13 files changed, 187 insertions, 201 deletions

diff --git a/src/core/hle/kernel/address_arbiter.cpp b/src/core/hle/kernel/address_arbiter.cpp
index 2b21657d..1e697fac 100644
--- a/src/core/hle/kernel/address_arbiter.cpp
+++ b/src/core/hle/kernel/address_arbiter.cpp
@@ -30,17 +30,17 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result WaitSynchronization(bool* wait) override {
+    ResultVal<bool> WaitSynchronization() override {
         // TODO(bunnei): ImplementMe
         ERROR_LOG(OSHLE, "(UNIMPLEMENTED)");
-        return 0;
+        return UnimplementedFunction(ErrorModule::OS);
     }
 };
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 /// Arbitrate an address
-Result ArbitrateAddress(Handle handle, ArbitrationType type, u32 address, s32 value) {
+ResultCode ArbitrateAddress(Handle handle, ArbitrationType type, u32 address, s32 value) {
     switch (type) {
 
     // Signal thread(s) waiting for arbitrate address...
@@ -65,9 +65,9 @@ Result ArbitrateAddress(Handle handle, ArbitrationType type, u32 address, s32 va
 
     default:
         ERROR_LOG(KERNEL, "unknown type=%d", type);
-        return -1;
+        return ResultCode(ErrorDescription::InvalidEnumValue, ErrorModule::Kernel, ErrorSummary::WrongArgument, ErrorLevel::Usage);
     }
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /// Create an address arbiter
diff --git a/src/core/hle/kernel/address_arbiter.h b/src/core/hle/kernel/address_arbiter.h
index 6886e479..8a5fb10b 100644
--- a/src/core/hle/kernel/address_arbiter.h
+++ b/src/core/hle/kernel/address_arbiter.h
@@ -28,7 +28,7 @@ enum class ArbitrationType : u32 {
 };
 
 /// Arbitrate an address
-Result ArbitrateAddress(Handle handle, ArbitrationType type, u32 address, s32 value);
+ResultCode ArbitrateAddress(Handle handle, ArbitrationType type, u32 address, s32 value);
 
 /// Create an address arbiter
 Handle CreateAddressArbiter(const std::string& name = "Unknown");
diff --git a/src/core/hle/kernel/archive.cpp b/src/core/hle/kernel/archive.cpp
index 900f484c..e11dddc8 100644
--- a/src/core/hle/kernel/archive.cpp
+++ b/src/core/hle/kernel/archive.cpp
@@ -9,8 +9,9 @@
 #include "core/file_sys/archive.h"
 #include "core/file_sys/archive_sdmc.h"
 #include "core/file_sys/directory.h"
-#include "core/hle/service/service.h"
 #include "core/hle/kernel/archive.h"
+#include "core/hle/result.h"
+#include "core/hle/service/service.h"
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // Kernel namespace
@@ -56,7 +57,7 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result SyncRequest(bool* wait) override {
+    ResultVal<bool> SyncRequest() override {
         u32* cmd_buff = Service::GetCommandBuffer();
         FileCommand cmd = static_cast<FileCommand>(cmd_buff[0]);
 
@@ -106,11 +107,11 @@ public:
         default:
         {
             ERROR_LOG(KERNEL, "Unknown command=0x%08X!", cmd);
-            return -1;
+            return UnimplementedFunction(ErrorModule::FS);
         }
         }
         cmd_buff[1] = 0; // No error
-        return 0;
+        return MakeResult<bool>(false);
     }
 
     /**
@@ -118,10 +119,10 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result WaitSynchronization(bool* wait) override {
+    ResultVal<bool> WaitSynchronization() override {
         // TODO(bunnei): ImplementMe
         ERROR_LOG(OSHLE, "(UNIMPLEMENTED)");
-        return 0;
+        return UnimplementedFunction(ErrorModule::FS);
     }
 };
 
@@ -141,7 +142,7 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result SyncRequest(bool* wait) override {
+    ResultVal<bool> SyncRequest() override {
         u32* cmd_buff = Service::GetCommandBuffer();
         FileCommand cmd = static_cast<FileCommand>(cmd_buff[0]);
         switch (cmd) {
@@ -183,7 +184,8 @@ public:
         case FileCommand::SetSize:
         {
             u64 size = cmd_buff[1] | ((u64)cmd_buff[2] << 32);
-            DEBUG_LOG(KERNEL, "SetSize %s %s size=%llu", GetTypeName().c_str(), GetName().c_str(), size);
+            DEBUG_LOG(KERNEL, "SetSize %s %s size=%llu",
+                    GetTypeName().c_str(), GetName().c_str(), size);
             backend->SetSize(size);
             break;
         }
@@ -198,11 +200,12 @@ public:
         // Unknown command...
         default:
             ERROR_LOG(KERNEL, "Unknown command=0x%08X!", cmd);
-            cmd_buff[1] = -1; // TODO(Link Mauve): use the correct error code for that.
-            return -1;
+            ResultCode error = UnimplementedFunction(ErrorModule::FS);
+            cmd_buff[1] = error.raw; // TODO(Link Mauve): use the correct error code for that.
+            return error;
         }
         cmd_buff[1] = 0; // No error
-        return 0;
+        return MakeResult<bool>(false);
     }
 
     /**
@@ -210,10 +213,10 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result WaitSynchronization(bool* wait) override {
+    ResultVal<bool> WaitSynchronization() override {
         // TODO(bunnei): ImplementMe
         ERROR_LOG(OSHLE, "(UNIMPLEMENTED)");
-        return 0;
+        return UnimplementedFunction(ErrorModule::FS);
     }
 };
 
@@ -233,7 +236,7 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result SyncRequest(bool* wait) override {
+    ResultVal<bool> SyncRequest() override {
         u32* cmd_buff = Service::GetCommandBuffer();
         DirectoryCommand cmd = static_cast<DirectoryCommand>(cmd_buff[0]);
         switch (cmd) {
@@ -243,8 +246,9 @@ public:
         {
             u32 count = cmd_buff[1];
             u32 address = cmd_buff[3];
-            FileSys::Entry* entries = reinterpret_cast<FileSys::Entry*>(Memory::GetPointer(address));
-            DEBUG_LOG(KERNEL, "Read %s %s: count=%d", GetTypeName().c_str(), GetName().c_str(), count);
+            auto entries = reinterpret_cast<FileSys::Entry*>(Memory::GetPointer(address));
+            DEBUG_LOG(KERNEL, "Read %s %s: count=%d",
+                    GetTypeName().c_str(), GetName().c_str(), count);
 
             // Number of entries actually read
             cmd_buff[2] = backend->Read(count, entries);
@@ -261,11 +265,12 @@ public:
         // Unknown command...
         default:
             ERROR_LOG(KERNEL, "Unknown command=0x%08X!", cmd);
-            cmd_buff[1] = -1; // TODO(Link Mauve): use the correct error code for that.
-            return -1;
+            ResultCode error = UnimplementedFunction(ErrorModule::FS);
+            cmd_buff[1] = error.raw; // TODO(Link Mauve): use the correct error code for that.
+            return error;
         }
         cmd_buff[1] = 0; // No error
-        return 0;
+        return MakeResult<bool>(false);
     }
 
     /**
@@ -273,10 +278,10 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result WaitSynchronization(bool* wait) override {
+    ResultVal<bool> WaitSynchronization() override {
         // TODO(bunnei): ImplementMe
         ERROR_LOG(OSHLE, "(UNIMPLEMENTED)");
-        return 0;
+        return UnimplementedFunction(ErrorModule::FS);
     }
 };
 
@@ -284,89 +289,59 @@ public:
 
 std::map<FileSys::Archive::IdCode, Handle> g_archive_map; ///< Map of file archives by IdCode
 
-/**
- * Opens an archive
- * @param id_code IdCode of the archive to open
- * @return Handle to archive if it exists, otherwise a null handle (0)
- */
-Handle OpenArchive(FileSys::Archive::IdCode id_code) {
+ResultVal<Handle> OpenArchive(FileSys::Archive::IdCode id_code) {
     auto itr = g_archive_map.find(id_code);
     if (itr == g_archive_map.end()) {
-        return 0;
+        return ResultCode(ErrorDescription::NotFound, ErrorModule::FS,
+                ErrorSummary::NotFound, ErrorLevel::Permanent);
     }
-    return itr->second;
+
+    return MakeResult<Handle>(itr->second);
 }
 
-/**
- * Closes an archive
- * @param id_code IdCode of the archive to open
- * @return Result of operation, 0 on success, otherwise error code
- */
-Result CloseArchive(FileSys::Archive::IdCode id_code) {
+ResultCode CloseArchive(FileSys::Archive::IdCode id_code) {
     auto itr = g_archive_map.find(id_code);
     if (itr == g_archive_map.end()) {
         ERROR_LOG(KERNEL, "Cannot close archive %d, does not exist!", (int)id_code);
-        return -1;
+        return InvalidHandle(ErrorModule::FS);
     }
 
     INFO_LOG(KERNEL, "Closed archive %d", (int) id_code);
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /**
  * Mounts an archive
  * @param archive Pointer to the archive to mount
- * @return Result of operation, 0 on success, otherwise error code
+ * @return Result of operation
  */
-Result MountArchive(Archive* archive) {
+ResultCode MountArchive(Archive* archive) {
     FileSys::Archive::IdCode id_code = archive->backend->GetIdCode();
-    if (0 != OpenArchive(id_code)) {
+    ResultVal<Handle> archive_handle = OpenArchive(id_code);
+    if (archive_handle.Succeeded()) {
         ERROR_LOG(KERNEL, "Cannot mount two archives with the same ID code! (%d)", (int) id_code);
-        return -1;
+        return archive_handle.Code();
     }
     g_archive_map[id_code] = archive->GetHandle();
     INFO_LOG(KERNEL, "Mounted archive %s", archive->GetName().c_str());
-    return 0;
+    return RESULT_SUCCESS;
 }
 
-/**
- * Creates an Archive
- * @param handle Handle to newly created archive object
- * @param backend File system backend interface to the archive
- * @param name Optional name of Archive
- * @return Newly created Archive object
- */
-Archive* CreateArchive(Handle& handle, FileSys::Archive* backend, const std::string& name) {
+ResultCode CreateArchive(FileSys::Archive* backend, const std::string& name) {
     Archive* archive = new Archive;
-    handle = Kernel::g_object_pool.Create(archive);
+    Handle handle = Kernel::g_object_pool.Create(archive);
     archive->name = name;
     archive->backend = backend;
 
-    MountArchive(archive);
-
-    return archive;
-}
-
-/**
- * Creates an Archive
- * @param backend File system backend interface to the archive
- * @param name Optional name of Archive
- * @return Handle to newly created Archive object
- */
-Handle CreateArchive(FileSys::Archive* backend, const std::string& name) {
-    Handle handle;
-    CreateArchive(handle, backend, name);
-    return handle;
+    ResultCode result = MountArchive(archive);
+    if (result.IsError()) {
+        return result;
+    }
+    
+    return RESULT_SUCCESS;
 }
 
-/**
- * Open a File from an Archive
- * @param archive_handle Handle to an open Archive object
- * @param path Path to the File inside of the Archive
- * @param mode Mode under which to open the File
- * @return Opened File object
- */
-Handle OpenFileFromArchive(Handle archive_handle, const FileSys::Path& path, const FileSys::Mode mode) {
+ResultVal<Handle> OpenFileFromArchive(Handle archive_handle, const FileSys::Path& path, const FileSys::Mode mode) {
     // TODO(bunnei): Binary type files get a raw file pointer to the archive. Currently, we create
     // the archive file handles at app loading, and then keep them persistent throughout execution.
     // Archives file handles are just reused and not actually freed until emulation shut down.
@@ -376,19 +351,24 @@ Handle OpenFileFromArchive(Handle archive_handle, const FileSys::Path& path, con
         // design. While the functionally of this is OK, our implementation decision to separate
         // normal files from archive file pointers is very likely wrong.
         // See https://github.com/citra-emu/citra/issues/205
-        return archive_handle;
+        return MakeResult<Handle>(archive_handle);
 
     File* file = new File;
     Handle handle = Kernel::g_object_pool.Create(file);
 
-    Archive* archive = Kernel::g_object_pool.GetFast<Archive>(archive_handle);
+    Archive* archive = Kernel::g_object_pool.Get<Archive>(archive_handle);
+    if (archive == nullptr) {
+        return InvalidHandle(ErrorModule::FS);
+    }
     file->path = path;
     file->backend = archive->backend->OpenFile(path, mode);
 
-    if (!file->backend)
-        return 0;
+    if (!file->backend) {
+        return ResultCode(ErrorDescription::NotFound, ErrorModule::FS,
+                ErrorSummary::NotFound, ErrorLevel::Permanent);
+    }
 
-    return handle;
+    return MakeResult<Handle>(handle);
 }
 
 /**
@@ -442,15 +422,18 @@ Result CreateDirectoryFromArchive(Handle archive_handle, const FileSys::Path& pa
  * @param path Path to the Directory inside of the Archive
  * @return Opened Directory object
  */
-Handle OpenDirectoryFromArchive(Handle archive_handle, const FileSys::Path& path) {
+ResultVal<Handle> OpenDirectoryFromArchive(Handle archive_handle, const FileSys::Path& path) {
     Directory* directory = new Directory;
     Handle handle = Kernel::g_object_pool.Create(directory);
 
-    Archive* archive = Kernel::g_object_pool.GetFast<Archive>(archive_handle);
+    Archive* archive = Kernel::g_object_pool.Get<Archive>(archive_handle);
+    if (archive == nullptr) {
+        return InvalidHandle(ErrorModule::FS);
+    }
     directory->path = path;
     directory->backend = archive->backend->OpenDirectory(path);
 
-    return handle;
+    return MakeResult<Handle>(handle);
 }
 
 /// Initialize archives
diff --git a/src/core/hle/kernel/archive.h b/src/core/hle/kernel/archive.h
index 95b3c665..6fc4f0f2 100644
--- a/src/core/hle/kernel/archive.h
+++ b/src/core/hle/kernel/archive.h
@@ -6,8 +6,9 @@
 
 #include "common/common_types.h"
 
-#include "core/hle/kernel/kernel.h"
 #include "core/file_sys/archive.h"
+#include "core/hle/kernel/kernel.h"
+#include "core/hle/result.h"
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // Kernel namespace
@@ -17,33 +18,31 @@ namespace Kernel {
 /**
  * Opens an archive
  * @param id_code IdCode of the archive to open
- * @return Handle to archive if it exists, otherwise a null handle (0)
+ * @return Handle to the opened archive
  */
-Handle OpenArchive(FileSys::Archive::IdCode id_code);
+ResultVal<Handle> OpenArchive(FileSys::Archive::IdCode id_code);
 
 /**
  * Closes an archive
  * @param id_code IdCode of the archive to open
- * @return true if it worked fine
  */
-Result CloseArchive(FileSys::Archive::IdCode id_code);
+ResultCode CloseArchive(FileSys::Archive::IdCode id_code);
 
 /**
  * Creates an Archive
  * @param backend File system backend interface to the archive
- * @param name Optional name of Archive
- * @return Handle to newly created Archive object
+ * @param name Name of Archive
  */
-Handle CreateArchive(FileSys::Archive* backend, const std::string& name);
+ResultCode CreateArchive(FileSys::Archive* backend, const std::string& name);
 
 /**
  * Open a File from an Archive
  * @param archive_handle Handle to an open Archive object
  * @param path Path to the File inside of the Archive
  * @param mode Mode under which to open the File
- * @return Opened File object
+ * @return Handle to the opened File object
  */
-Handle OpenFileFromArchive(Handle archive_handle, const FileSys::Path& path, const FileSys::Mode mode);
+ResultVal<Handle> OpenFileFromArchive(Handle archive_handle, const FileSys::Path& path, const FileSys::Mode mode);
 
 /**
  * Delete a File from an Archive
@@ -73,9 +72,9 @@ Result CreateDirectoryFromArchive(Handle archive_handle, const FileSys::Path& pa
  * Open a Directory from an Archive
  * @param archive_handle Handle to an open Archive object
  * @param path Path to the Directory inside of the Archive
- * @return Opened Directory object
+ * @return Handle to the opened File object
  */
-Handle OpenDirectoryFromArchive(Handle archive_handle, const FileSys::Path& path);
+ResultVal<Handle> OpenDirectoryFromArchive(Handle archive_handle, const FileSys::Path& path);
 
 /// Initialize archives
 void ArchiveInit();
diff --git a/src/core/hle/kernel/event.cpp b/src/core/hle/kernel/event.cpp
index e0117c0b..8a2925a3 100644
--- a/src/core/hle/kernel/event.cpp
+++ b/src/core/hle/kernel/event.cpp
@@ -35,8 +35,8 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result WaitSynchronization(bool* wait) override {
-        *wait = locked;
+    ResultVal<bool> WaitSynchronization() override {
+        bool wait = locked;
         if (locked) {
             Handle thread = GetCurrentThreadHandle();
             if (std::find(waiting_threads.begin(), waiting_threads.end(), thread) == waiting_threads.end()) {
@@ -47,7 +47,7 @@ public:
         if (reset_type != RESETTYPE_STICKY && !permanent_locked) {
             locked = true;
         }
-        return 0;
+        return MakeResult<bool>(wait);
     }
 };
 
@@ -57,12 +57,12 @@ public:
  * @param permanent_locked Boolean permanent locked value to set event
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result SetPermanentLock(Handle handle, const bool permanent_locked) {
-    Event* evt = g_object_pool.GetFast<Event>(handle);
-    _assert_msg_(KERNEL, (evt != nullptr), "called, but event is nullptr!");
+ResultCode SetPermanentLock(Handle handle, const bool permanent_locked) {
+    Event* evt = g_object_pool.Get<Event>(handle);
+    if (evt == nullptr) return InvalidHandle(ErrorModule::Kernel);
 
     evt->permanent_locked = permanent_locked;
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /**
@@ -71,14 +71,14 @@ Result SetPermanentLock(Handle handle, const bool permanent_locked) {
  * @param locked Boolean locked value to set event
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result SetEventLocked(const Handle handle, const bool locked) {
-    Event* evt = g_object_pool.GetFast<Event>(handle);
-    _assert_msg_(KERNEL, (evt != nullptr), "called, but event is nullptr!");
+ResultCode SetEventLocked(const Handle handle, const bool locked) {
+    Event* evt = g_object_pool.Get<Event>(handle);
+    if (evt == nullptr) return InvalidHandle(ErrorModule::Kernel);
 
     if (!evt->permanent_locked) {
         evt->locked = locked;
     }
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /**
@@ -86,9 +86,9 @@ Result SetEventLocked(const Handle handle, const bool locked) {
  * @param handle Handle to event to signal
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result SignalEvent(const Handle handle) {
-    Event* evt = g_object_pool.GetFast<Event>(handle);
-    _assert_msg_(KERNEL, (evt != nullptr), "called, but event is nullptr!");
+ResultCode SignalEvent(const Handle handle) {
+    Event* evt = g_object_pool.Get<Event>(handle);
+    if (evt == nullptr) return InvalidHandle(ErrorModule::Kernel);
 
     // Resume threads waiting for event to signal
     bool event_caught = false;
@@ -106,7 +106,7 @@ Result SignalEvent(const Handle handle) {
     if (!evt->permanent_locked) {
         evt->locked = event_caught;
     }
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /**
@@ -114,14 +114,14 @@ Result SignalEvent(const Handle handle) {
  * @param handle Handle to event to clear
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result ClearEvent(Handle handle) {
-    Event* evt = g_object_pool.GetFast<Event>(handle);
-    _assert_msg_(KERNEL, (evt != nullptr), "called, but event is nullptr!");
+ResultCode ClearEvent(Handle handle) {
+    Event* evt = g_object_pool.Get<Event>(handle);
+    if (evt == nullptr) return InvalidHandle(ErrorModule::Kernel);
 
     if (!evt->permanent_locked) {
         evt->locked = true;
     }
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /**
diff --git a/src/core/hle/kernel/event.h b/src/core/hle/kernel/event.h
index 6add7289..6c17ed23 100644
--- a/src/core/hle/kernel/event.h
+++ b/src/core/hle/kernel/event.h
@@ -17,7 +17,7 @@ namespace Kernel {
  * @param locked Boolean locked value to set event
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result SetEventLocked(const Handle handle, const bool locked);
+ResultCode SetEventLocked(const Handle handle, const bool locked);
 
 /**
  * Hackish function to set an events permanent lock state, used to pass through synch blocks
@@ -25,21 +25,21 @@ Result SetEventLocked(const Handle handle, const bool locked);
  * @param permanent_locked Boolean permanent locked value to set event
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result SetPermanentLock(Handle handle, const bool permanent_locked);
+ResultCode SetPermanentLock(Handle handle, const bool permanent_locked);
 
 /**
  * Signals an event
  * @param handle Handle to event to signal
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result SignalEvent(const Handle handle);
+ResultCode SignalEvent(const Handle handle);
 
 /**
  * Clears an event
  * @param handle Handle to event to clear
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result ClearEvent(Handle handle);
+ResultCode ClearEvent(Handle handle);
 
 /**
  * Creates an event
diff --git a/src/core/hle/kernel/kernel.h b/src/core/hle/kernel/kernel.h
index e0c94f18..8d3937ce 100644
--- a/src/core/hle/kernel/kernel.h
+++ b/src/core/hle/kernel/kernel.h
@@ -7,6 +7,7 @@
 #include <array>
 #include <string>
 #include "common/common.h"
+#include "core/hle/result.h"
 
 typedef u32 Handle;
 typedef s32 Result;
@@ -52,21 +53,19 @@ public:
     virtual Kernel::HandleType GetHandleType() const = 0;
 
     /**
-     * Synchronize kernel object
-     * @param wait Boolean wait set if current thread should wait as a result of sync operation
-     * @return Result of operation, 0 on success, otherwise error code
+     * Synchronize kernel object.
+     * @return True if the current thread should wait as a result of the sync
      */
-    virtual Result SyncRequest(bool* wait) {
+    virtual ResultVal<bool> SyncRequest() {
         ERROR_LOG(KERNEL, "(UNIMPLEMENTED)");
-        return -1;
+        return UnimplementedFunction(ErrorModule::Kernel);
     }
 
     /**
-     * Wait for kernel object to synchronize
-     * @param wait Boolean wait set if current thread should wait as a result of sync operation
-     * @return Result of operation, 0 on success, otherwise error code
+     * Wait for kernel object to synchronize.
+     * @return True if the current thread should wait as a result of the wait
      */
-    virtual Result WaitSynchronization(bool* wait) = 0;
+    virtual ResultVal<bool> WaitSynchronization() = 0;
 };
 
 class ObjectPool : NonCopyable {
@@ -80,38 +79,29 @@ public:
     static Object* CreateByIDType(int type);
 
     template <class T>
-    u32 Destroy(Handle handle) {
-        u32 error;
-        if (Get<T>(handle, error)) {
+    void Destroy(Handle handle) {
+        if (Get<T>(handle)) {
             occupied[handle - HANDLE_OFFSET] = false;
             delete pool[handle - HANDLE_OFFSET];
         }
-        return error;
     }
 
     bool IsValid(Handle handle);
 
     template <class T>
-    T* Get(Handle handle, u32& outError) {
+    T* Get(Handle handle) {
         if (handle < HANDLE_OFFSET || handle >= HANDLE_OFFSET + MAX_COUNT || !occupied[handle - HANDLE_OFFSET]) {
-            // Tekken 6 spams 0x80020001 gets wrong with no ill effects, also on the real PSP
-            if (handle != 0 && (u32)handle != 0x80020001) {
+            if (handle != 0) {
                 WARN_LOG(KERNEL, "Kernel: Bad object handle %i (%08x)", handle, handle);
             }
-            outError = 0;//T::GetMissingErrorCode();
-            return 0;
+            return nullptr;
         } else {
-            // Previously we had a dynamic_cast here, but since RTTI was disabled traditionally,
-            // it just acted as a static case and everything worked. This means that we will never
-            // see the Wrong type object error below, but we'll just have to live with that danger.
-            T* t = static_cast<T*>(pool[handle - HANDLE_OFFSET]);
-            if (t == 0 || t->GetHandleType() != T::GetStaticHandleType()) {
+            Object* t = pool[handle - HANDLE_OFFSET];
+            if (t->GetHandleType() != T::GetStaticHandleType()) {
                 WARN_LOG(KERNEL, "Kernel: Wrong object type for %i (%08x)", handle, handle);
-                outError = 0;//T::GetMissingErrorCode();
-                return 0;
+                return nullptr;
             }
-            outError = 0;//SCE_KERNEL_ERROR_OK;
-            return t;
+            return static_cast<T*>(t);
         }
     }
 
diff --git a/src/core/hle/kernel/mutex.cpp b/src/core/hle/kernel/mutex.cpp
index 31129fd8..e4ff1ef4 100644
--- a/src/core/hle/kernel/mutex.cpp
+++ b/src/core/hle/kernel/mutex.cpp
@@ -32,10 +32,10 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result SyncRequest(bool* wait) override {
+    ResultVal<bool> SyncRequest() override {
         // TODO(bunnei): ImplementMe
         locked = true;
-        return 0;
+        return MakeResult<bool>(false);
     }
 
     /**
@@ -43,15 +43,14 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result WaitSynchronization(bool* wait) override {
+    ResultVal<bool> WaitSynchronization() override {
         // TODO(bunnei): ImplementMe
-        *wait = locked;
-
+        bool wait = locked;
         if (locked) {
             Kernel::WaitCurrentThread(WAITTYPE_MUTEX, GetHandle());
         }
 
-        return 0;
+        return MakeResult<bool>(wait);
     }
 };
 
@@ -119,15 +118,17 @@ bool ReleaseMutex(Mutex* mutex) {
  * Releases a mutex
  * @param handle Handle to mutex to release
  */
-Result ReleaseMutex(Handle handle) {
-    Mutex* mutex = Kernel::g_object_pool.GetFast<Mutex>(handle);
-
-    _assert_msg_(KERNEL, (mutex != nullptr), "ReleaseMutex tried to release a nullptr mutex!");
+ResultCode ReleaseMutex(Handle handle) {
+    Mutex* mutex = Kernel::g_object_pool.Get<Mutex>(handle);
+    if (mutex == nullptr) return InvalidHandle(ErrorModule::Kernel);
 
     if (!ReleaseMutex(mutex)) {
-        return -1;
+        // TODO(yuriks): Verify error code, this one was pulled out of thin air. I'm not even sure
+        // what error condition this is supposed to be signaling.
+        return ResultCode(ErrorDescription::AlreadyDone, ErrorModule::Kernel,
+                ErrorSummary::NothingHappened, ErrorLevel::Temporary);
     }
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /**
diff --git a/src/core/hle/kernel/mutex.h b/src/core/hle/kernel/mutex.h
index 313ba6fe..233d8c42 100644
--- a/src/core/hle/kernel/mutex.h
+++ b/src/core/hle/kernel/mutex.h
@@ -15,7 +15,7 @@ namespace Kernel {
  * @param handle Handle to mutex to release
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result ReleaseMutex(Handle handle);
+ResultCode ReleaseMutex(Handle handle);
 
 /**
  * Creates a mutex
diff --git a/src/core/hle/kernel/shared_memory.cpp b/src/core/hle/kernel/shared_memory.cpp
index 7ef3e54c..b91fc98d 100644
--- a/src/core/hle/kernel/shared_memory.cpp
+++ b/src/core/hle/kernel/shared_memory.cpp
@@ -21,10 +21,10 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result WaitSynchronization(bool* wait) override {
+    ResultVal<bool> WaitSynchronization() override {
         // TODO(bunnei): ImplementMe
         ERROR_LOG(OSHLE, "(UNIMPLEMENTED)");
-        return 0;
+        return UnimplementedFunction(ErrorModule::OS);
     }
 
     u32 base_address;                   ///< Address of shared memory block in RAM
@@ -67,22 +67,23 @@ Handle CreateSharedMemory(const std::string& name) {
  * @param other_permissions Memory block map other permissions (specified by SVC field)
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result MapSharedMemory(u32 handle, u32 address, MemoryPermission permissions,
+ResultCode MapSharedMemory(u32 handle, u32 address, MemoryPermission permissions,
     MemoryPermission other_permissions) {
 
     if (address < Memory::SHARED_MEMORY_VADDR || address >= Memory::SHARED_MEMORY_VADDR_END) {
         ERROR_LOG(KERNEL, "cannot map handle=0x%08X, address=0x%08X outside of shared mem bounds!",
             handle, address);
-        return -1;
+        return ResultCode(ErrorDescription::InvalidAddress, ErrorModule::Kernel,
+                ErrorSummary::InvalidArgument, ErrorLevel::Permanent);
     }
-    SharedMemory* shared_memory = Kernel::g_object_pool.GetFast<SharedMemory>(handle);
-    _assert_msg_(KERNEL, (shared_memory != nullptr), "handle 0x%08X is not valid!", handle);
+    SharedMemory* shared_memory = Kernel::g_object_pool.Get<SharedMemory>(handle);
+    if (shared_memory == nullptr) return InvalidHandle(ErrorModule::Kernel);
 
     shared_memory->base_address = address;
     shared_memory->permissions = permissions;
     shared_memory->other_permissions = other_permissions;
 
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /**
@@ -91,15 +92,17 @@ Result MapSharedMemory(u32 handle, u32 address, MemoryPermission permissions,
  * @param offset Offset from the start of the shared memory block to get pointer
  * @return Pointer to the shared memory block from the specified offset
  */
-u8* GetSharedMemoryPointer(Handle handle, u32 offset) {
-    SharedMemory* shared_memory = Kernel::g_object_pool.GetFast<SharedMemory>(handle);
-    _assert_msg_(KERNEL, (shared_memory != nullptr), "handle 0x%08X is not valid!", handle);
+ResultVal<u8*> GetSharedMemoryPointer(Handle handle, u32 offset) {
+    SharedMemory* shared_memory = Kernel::g_object_pool.Get<SharedMemory>(handle);
+    if (shared_memory == nullptr) return InvalidHandle(ErrorModule::Kernel);
 
     if (0 != shared_memory->base_address)
-        return Memory::GetPointer(shared_memory->base_address + offset);
+        return MakeResult<u8*>(Memory::GetPointer(shared_memory->base_address + offset));
 
     ERROR_LOG(KERNEL, "memory block handle=0x%08X not mapped!", handle);
-    return nullptr;
+    // TODO(yuriks): Verify error code.
+    return ResultCode(ErrorDescription::InvalidAddress, ErrorModule::Kernel,
+            ErrorSummary::InvalidState, ErrorLevel::Permanent);
 }
 
 } // namespace
diff --git a/src/core/hle/kernel/shared_memory.h b/src/core/hle/kernel/shared_memory.h
index 0aec0353..6ed42708 100644
--- a/src/core/hle/kernel/shared_memory.h
+++ b/src/core/hle/kernel/shared_memory.h
@@ -34,7 +34,7 @@ Handle CreateSharedMemory(const std::string& name="Unknown");
  * @param other_permissions Memory block map other permissions (specified by SVC field)
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result MapSharedMemory(u32 handle, u32 address, MemoryPermission permissions,
+ResultCode MapSharedMemory(Handle handle, u32 address, MemoryPermission permissions,
     MemoryPermission other_permissions);
 
 /**
@@ -43,6 +43,6 @@ Result MapSharedMemory(u32 handle, u32 address, MemoryPermission permissions,
  * @param offset Offset from the start of the shared memory block to get pointer
  * @return Pointer to the shared memory block from the specified offset
  */
-u8* GetSharedMemoryPointer(Handle handle, u32 offset);
+ResultVal<u8*> GetSharedMemoryPointer(Handle handle, u32 offset);
 
 } // namespace
diff --git a/src/core/hle/kernel/thread.cpp b/src/core/hle/kernel/thread.cpp
index cc70cbca..b01779f2 100644
--- a/src/core/hle/kernel/thread.cpp
+++ b/src/core/hle/kernel/thread.cpp
@@ -11,10 +11,11 @@
 #include "common/thread_queue_list.h"
 
 #include "core/core.h"
-#include "core/mem_map.h"
 #include "core/hle/hle.h"
 #include "core/hle/kernel/kernel.h"
 #include "core/hle/kernel/thread.h"
+#include "core/hle/result.h"
+#include "core/mem_map.h"
 
 namespace Kernel {
 
@@ -38,16 +39,17 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result WaitSynchronization(bool* wait) override {
+    ResultVal<bool> WaitSynchronization() override {
         if (status != THREADSTATUS_DORMANT) {
             Handle thread = GetCurrentThreadHandle();
             if (std::find(waiting_threads.begin(), waiting_threads.end(), thread) == waiting_threads.end()) {
                 waiting_threads.push_back(thread);
             }
             WaitCurrentThread(WAITTYPE_THREADEND, this->GetHandle());
-            *wait = true;
+            return MakeResult<bool>(true);
+        } else {
+            return MakeResult<bool>(false);
         }
-        return 0;
     }
 
     ThreadContext context;
@@ -144,9 +146,9 @@ void ChangeReadyState(Thread* t, bool ready) {
 }
 
 /// Verify that a thread has not been released from waiting
-inline bool VerifyWait(const Handle& handle, WaitType type, Handle wait_handle) {
-    Thread* thread = g_object_pool.GetFast<Thread>(handle);
-    _assert_msg_(KERNEL, (thread != nullptr), "called, but thread is nullptr!");
+inline bool VerifyWait(Handle handle, WaitType type, Handle wait_handle) {
+    Thread* thread = g_object_pool.Get<Thread>(handle);
+    _dbg_assert_(KERNEL, thread != nullptr);
 
     if (type != thread->wait_type || wait_handle != thread->wait_handle)
         return false;
@@ -155,9 +157,9 @@ inline bool VerifyWait(const Handle& handle, WaitType type, Handle wait_handle)
 }
 
 /// Stops the current thread
-void StopThread(Handle handle, const char* reason) {
-    Thread* thread = g_object_pool.GetFast<Thread>(handle);
-    _assert_msg_(KERNEL, (thread != nullptr), "called, but thread is nullptr!");
+ResultCode StopThread(Handle handle, const char* reason) {
+    Thread* thread = g_object_pool.Get<Thread>(handle);
+    if (thread == nullptr) return InvalidHandle(ErrorModule::Kernel);
 
     ChangeReadyState(thread, false);
     thread->status = THREADSTATUS_DORMANT;
@@ -172,6 +174,8 @@ void StopThread(Handle handle, const char* reason) {
     // Stopped threads are never waiting.
     thread->wait_type = WAITTYPE_NONE;
     thread->wait_handle = 0;
+
+    return RESULT_SUCCESS;
 }
 
 /// Changes a threads state
@@ -201,7 +205,9 @@ Handle ArbitrateHighestPriorityThread(u32 arbiter, u32 address) {
         if (!VerifyWait(handle, WAITTYPE_ARB, arbiter))
             continue;
 
-        Thread* thread = g_object_pool.GetFast<Thread>(handle);
+        Thread* thread = g_object_pool.Get<Thread>(handle);
+        if (thread == nullptr)
+            continue; // TODO(yuriks): Thread handle will hang around forever. Should clean up.
         if(thread->current_priority <= priority) {
             highest_priority_thread = handle;
             priority = thread->current_priority;
@@ -272,7 +278,7 @@ Thread* NextThread() {
     if (next == 0) {
         return nullptr;
     }
-    return Kernel::g_object_pool.GetFast<Thread>(next);
+    return Kernel::g_object_pool.Get<Thread>(next);
 }
 
 /**
@@ -289,8 +295,7 @@ void WaitCurrentThread(WaitType wait_type, Handle wait_handle) {
 
 /// Resumes a thread from waiting by marking it as "ready"
 void ResumeThreadFromWait(Handle handle) {
-    u32 error;
-    Thread* thread = Kernel::g_object_pool.Get<Thread>(handle, error);
+    Thread* thread = Kernel::g_object_pool.Get<Thread>(handle);
     if (thread) {
         thread->status &= ~THREADSTATUS_WAIT;
         if (!(thread->status & (THREADSTATUS_WAITSUSPEND | THREADSTATUS_DORMANT | THREADSTATUS_DEAD))) {
@@ -378,19 +383,23 @@ Handle CreateThread(const char* name, u32 entry_point, s32 priority, u32 arg, s3
 }
 
 /// Get the priority of the thread specified by handle
-u32 GetThreadPriority(const Handle handle) {
-    Thread* thread = g_object_pool.GetFast<Thread>(handle);
-    _assert_msg_(KERNEL, (thread != nullptr), "called, but thread is nullptr!");
-    return thread->current_priority;
+ResultVal<u32> GetThreadPriority(const Handle handle) {
+    Thread* thread = g_object_pool.Get<Thread>(handle);
+    if (thread == nullptr) return InvalidHandle(ErrorModule::Kernel);
+
+    return MakeResult<u32>(thread->current_priority);
 }
 
 /// Set the priority of the thread specified by handle
-Result SetThreadPriority(Handle handle, s32 priority) {
+ResultCode SetThreadPriority(Handle handle, s32 priority) {
     Thread* thread = nullptr;
     if (!handle) {
         thread = GetCurrentThread(); // TODO(bunnei): Is this correct behavior?
     } else {
-        thread = g_object_pool.GetFast<Thread>(handle);
+        thread = g_object_pool.Get<Thread>(handle);
+        if (thread == nullptr) {
+            return InvalidHandle(ErrorModule::Kernel);
+        }
     }
     _assert_msg_(KERNEL, (thread != nullptr), "called, but thread is nullptr!");
 
@@ -417,7 +426,7 @@ Result SetThreadPriority(Handle handle, s32 priority) {
         thread_ready_queue.push_back(thread->current_priority, handle);
     }
 
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /// Sets up the primary application thread
diff --git a/src/core/hle/kernel/thread.h b/src/core/hle/kernel/thread.h
index 2a43797e..ce63a70d 100644
--- a/src/core/hle/kernel/thread.h
+++ b/src/core/hle/kernel/thread.h
@@ -6,6 +6,7 @@
 
 #include "common/common_types.h"
 #include "core/hle/kernel/kernel.h"
+#include "core/hle/result.h"
 
 enum ThreadPriority {
     THREADPRIO_HIGHEST      = 0,    ///< Highest thread priority
@@ -55,7 +56,7 @@ Handle SetupMainThread(s32 priority, int stack_size=Kernel::DEFAULT_STACK_SIZE);
 void Reschedule();
 
 /// Stops the current thread
-void StopThread(Handle thread, const char* reason);
+ResultCode StopThread(Handle thread, const char* reason);
 
 /// Resumes a thread from waiting by marking it as "ready"
 void ResumeThreadFromWait(Handle handle);
@@ -80,10 +81,10 @@ void WaitCurrentThread(WaitType wait_type, Handle wait_handle=GetCurrentThreadHa
 void WaitThread_Synchronization();
 
 /// Get the priority of the thread specified by handle
-u32 GetThreadPriority(const Handle handle);
+ResultVal<u32> GetThreadPriority(const Handle handle);
 
 /// Set the priority of the thread specified by handle
-Result SetThreadPriority(Handle handle, s32 priority);
+ResultCode SetThreadPriority(Handle handle, s32 priority);
 
 /// Initialize threading
 void ThreadingInit();