Services/APT: Implemented the Store/LoadSysMenuArg functions.

They are called by the Home Menu during initialization.

These functions will not see much use until we actually implement application jumping and system rebooting. For now we just need them to prevent some unmapped reads in the Home Menu due to the static buffers not being properly set up.

src/core/hle/service/apt/apt.cpp

@@ -650,6 +650,37 @@ void Module::APTInterface::CloseLibraryApplet(Kernel::HLERequestContext& ctx) {
     rb.Push(apt->applet_manager->CloseLibraryApplet(std::move(object), std::move(buffer)));
 }
 
+void Module::APTInterface::LoadSysMenuArg(Kernel::HLERequestContext& ctx) {
+    IPC::RequestParser rp(ctx, 0x36, 1, 0); // 0x00360040
+    const auto size = std::min(std::size_t{rp.Pop<u32>()}, SysMenuArgSize);
+
+    // This service function does not clear the buffer.
+
+    std::vector<u8> buffer(size);
+    std::copy_n(apt->sys_menu_arg_buffer.cbegin(), size, buffer.begin());
+
+    IPC::RequestBuilder rb = rp.MakeBuilder(1, 2);
+    rb.Push(RESULT_SUCCESS);
+    rb.PushStaticBuffer(std::move(buffer), 0);
+
+    LOG_DEBUG(Service_APT, "called");
+}
+
+void Module::APTInterface::StoreSysMenuArg(Kernel::HLERequestContext& ctx) {
+    IPC::RequestParser rp(ctx, 0x37, 1, 2); // 0x00370042
+    const auto size = std::min(std::size_t{rp.Pop<u32>()}, SysMenuArgSize);
+    const auto& buffer = rp.PopStaticBuffer();
+
+    ASSERT_MSG(buffer.size() >= size, "Buffer too small to hold requested data");
+
+    std::copy_n(buffer.cbegin(), size, apt->sys_menu_arg_buffer.begin());
+
+    IPC::RequestBuilder rb = rp.MakeBuilder(1, 0);
+    rb.Push(RESULT_SUCCESS);
+
+    LOG_DEBUG(Service_APT, "called");
+}
+
 void Module::APTInterface::SendCaptureBufferInfo(Kernel::HLERequestContext& ctx) {
     IPC::RequestParser rp(ctx, 0x40, 1, 2); // 0x00400042
     u32 size = rp.Pop<u32>();