fs: add skeleton dir for sysmodule code

Please note this isn't likely to immediately be the active ams project.

libraries/libstratosphere/source/fssystem/fssystem_service_context.cpp

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+
+namespace ams::fssystem {
+
+    namespace {
+
+        os::SdkThreadLocalStorage g_tls_service_context;
+
+    }
+
+    void RegisterServiceContext(ServiceContext *context) {
+        /* Check pre-conditions. */
+        AMS_ASSERT(context != nullptr);
+        AMS_ASSERT(g_tls_service_context.GetValue() == 0);
+
+        /* Register context. */
+        g_tls_service_context.SetValue(reinterpret_cast<uintptr_t>(context));
+    }
+
+    void UnregisterServiceContext() {
+        /* Unregister context. */
+        g_tls_service_context.SetValue(0);
+    }
+
+    ServiceContext *GetServiceContext() {
+        /* Get context. */
+        auto * const context = reinterpret_cast<ServiceContext *>(g_tls_service_context.GetValue());
+        AMS_ASSERT(context != nullptr);
+
+        return context;
+    }
+
+}