Kernel/Loader: Grab the system mode from the NCCH ExHeader.

3dsx and elf files default to system mode 2 (96MB allocated to the application).

This allows Home Menu to boot without modifications.
Closes #1849

src/citra/citra.cpp

@@ -129,16 +129,23 @@ int main(int argc, char** argv) {
 
     std::unique_ptr<EmuWindow_SDL2> emu_window = std::make_unique<EmuWindow_SDL2>();
 
-    System::Init(emu_window.get());
-    SCOPE_EXIT({ System::Shutdown(); });
-
     std::unique_ptr<Loader::AppLoader> loader = Loader::GetLoader(boot_filename);
     if (!loader) {
         LOG_CRITICAL(Frontend, "Failed to obtain loader for %s!", boot_filename.c_str());
         return -1;
     }
 
-    Loader::ResultStatus load_result = loader->Load();
+    u32 system_mode;
+    Loader::ResultStatus load_result = loader->LoadKernelSystemMode(system_mode);
+    if (Loader::ResultStatus::Success != load_result) {
+        LOG_CRITICAL(Frontend, "Failed to load ROM (Error %i)!", load_result);
+        return -1;
+    }
+
+    System::Init(emu_window.get(), system_mode);
+    SCOPE_EXIT({ System::Shutdown(); });
+
+    load_result = loader->Load();
     if (Loader::ResultStatus::Success != load_result) {
         LOG_CRITICAL(Frontend, "Failed to load ROM (Error %i)!", load_result);
         return -1;

src/citra_qt/main.cpp

@@ -253,7 +253,7 @@ void GMainWindow::OnDisplayTitleBars(bool show) {
     }
 }
 
-bool GMainWindow::InitializeSystem() {
+bool GMainWindow::InitializeSystem(u32 system_mode) {
     // Shutdown previous session if the emu thread is still active...
     if (emu_thread != nullptr)
         ShutdownGame();
@@ -270,7 +270,7 @@ bool GMainWindow::InitializeSystem() {
     }
 
     // Initialize the core emulation
-    System::Result system_result = System::Init(render_window);
+    System::Result system_result = System::Init(render_window, system_mode);
     if (System::Result::Success != system_result) {
         switch (system_result) {
         case System::Result::ErrorInitVideoCore:
@@ -299,8 +299,21 @@ bool GMainWindow::LoadROM(const std::string& filename) {
         return false;
     }
 
+    u32 system_mode;
+    Loader::ResultStatus load_result = app_loader->LoadKernelSystemMode(system_mode);
+    if (Loader::ResultStatus::Success != load_result) {
+        LOG_CRITICAL(Frontend, "Failed to load ROM!", load_result);
+        QMessageBox::critical(this, tr("Error while loading ROM!"),
+                              tr("Could not determine the system mode."));
+        return false;
+    }
+
+    if (!InitializeSystem(system_mode))
+        return false;
+
     Loader::ResultStatus result = app_loader->Load();
     if (Loader::ResultStatus::Success != result) {
+        System::Shutdown();
         LOG_CRITICAL(Frontend, "Failed to load ROM!");
 
         switch (result) {
@@ -338,14 +351,9 @@ void GMainWindow::BootGame(const std::string& filename) {
     LOG_INFO(Frontend, "Citra starting...");
     StoreRecentFile(filename); // Put the filename on top of the list
 
-    if (!InitializeSystem())
+    if (!LoadROM(filename))
         return;
 
-    if (!LoadROM(filename)) {
-        System::Shutdown();
-        return;
-    }
-
     // Create and start the emulation thread
     emu_thread = std::make_unique<EmuThread>(render_window);
     emit EmulationStarting(emu_thread.get());

src/citra_qt/main.h

@@ -60,7 +60,12 @@ signals:
     void EmulationStopping();
 
 private:
-    bool InitializeSystem();
+    /**
+     * Initializes the emulation system.
+     * @param system_mode The system mode with which to intialize the kernel.
+     * @returns Whether the system was properly initialized.
+     */
+    bool InitializeSystem(u32 system_mode);
     bool LoadROM(const std::string& filename);
     void BootGame(const std::string& filename);
     void ShutdownGame();

src/core/hle/kernel/kernel.cpp

@@ -124,13 +124,11 @@ void HandleTable::Clear() {
 }
 
 /// Initialize the kernel
-void Init() {
+void Init(u32 system_mode) {
     ConfigMem::Init();
     SharedPage::Init();
 
-    // TODO(yuriks): The memory type parameter needs to be determined by the ExHeader field instead
-    // For now it defaults to the one with a largest allocation to the app
-    Kernel::MemoryInit(2); // Allocates 96MB to the application
+    Kernel::MemoryInit(system_mode);
 
     Kernel::ResourceLimitsInit();
     Kernel::ThreadingInit();

src/core/hle/kernel/kernel.h

@@ -286,8 +286,8 @@ private:
 
 extern HandleTable g_handle_table;
 
-/// Initialize the kernel
-void Init();
+/// Initialize the kernel with the specified system mode.
+void Init(u32 system_mode);
 
 /// Shutdown the kernel
 void Shutdown();

src/core/loader/loader.h

@@ -95,6 +95,17 @@ public:
      */
     virtual ResultStatus Load() = 0;
 
+    /**
+     * Loads the system mode that this application needs.
+     * This function defaults to 2 (96MB allocated to the application) if it can't read the information.
+     * @param system_mode Out variable where the system mode will be stored.
+     * @returns ResultStatus result of the operation
+     */
+    virtual ResultStatus LoadKernelSystemMode(u32& system_mode) {
+        system_mode = 2; // 96MB allocated to the application.
+        return ResultStatus::Success;
+    }
+
     /**
      * Get the code (typically .code section) of the application
      * @param buffer Reference to buffer to store data

src/core/loader/ncch.cpp

@@ -117,6 +117,14 @@ FileType AppLoader_NCCH::IdentifyType(FileUtil::IOFile& file) {
     return FileType::Error;
 }
 
+ResultStatus AppLoader_NCCH::LoadKernelSystemMode(u32& memory_type) {
+    ResultStatus result = LoadExeFS();
+    if (result != ResultStatus::Success)
+        return result;
+    memory_type = exheader_header.arm11_system_local_caps.system_mode;
+    return ResultStatus::Success;
+}
+
 ResultStatus AppLoader_NCCH::LoadExec() {
     using Kernel::SharedPtr;
     using Kernel::CodeSet;
@@ -277,6 +285,7 @@ ResultStatus AppLoader_NCCH::LoadExeFS() {
     LOG_DEBUG(Loader, "Core version:                %d", core_version);
     LOG_DEBUG(Loader, "Thread priority:             0x%X", priority);
     LOG_DEBUG(Loader, "Resource limit category:     %d", resource_limit_category);
+    LOG_DEBUG(Loader, "System Mode:                 %d", exheader_header.arm11_system_local_caps.system_mode);
 
     if (exheader_header.arm11_system_local_caps.program_id != ncch_header.program_id) {
         LOG_ERROR(Loader, "ExHeader Program ID mismatch: the ROM is probably encrypted.");

src/core/loader/ncch.h

@@ -185,6 +185,13 @@ public:
      */
     ResultStatus Load() override;
 
+    /**
+     * Loads the Exheader and returns the system mode for this application.
+     * @param system_mode Out variable where the system mode will be stored.
+     * @return ResultStatus result of the operation
+     */
+    ResultStatus LoadKernelSystemMode(u32& system_mode);
+
     /**
      * Get the code (typically .code section) of the application
      * @param buffer Reference to buffer to store data

src/core/system.cpp

@@ -17,12 +17,12 @@ namespace System {
 
 static bool is_powered_on{false};
 
-Result Init(EmuWindow* emu_window) {
+Result Init(EmuWindow* emu_window, u32 system_mode) {
     Core::Init();
     CoreTiming::Init();
     Memory::Init();
     HW::Init();
-    Kernel::Init();
+    Kernel::Init(system_mode);
     HLE::Init();
     if (!VideoCore::Init(emu_window)) {
         return Result::ErrorInitVideoCore;

src/core/system.h

@@ -15,7 +15,7 @@ enum class Result {
     ErrorInitVideoCore, ///< Something went wrong during video core init
 };
 
-Result Init(EmuWindow* emu_window);
+Result Init(EmuWindow* emu_window, u32 system_mode);
 bool IsPoweredOn();
 void Shutdown();
 }