global variable for all controller and views

At first, a config file is appropriate for this kind of things but you may also use another approach, which is as given below (Laravel – 4):

// You can keep this in your filters.php file
App::before(function($request) {
    App::singleton('site_settings', function(){
        return Setting::all();
    });

    // If you use this line of code then it'll be available in any view
    // as $site_settings but you may also use app('site_settings') as well
    View::share('site_settings', app('site_settings'));
});

To get the same data in any controller you may use:

$site_settings = app('site_settings');

There are many ways, just use one or another, which one you prefer but I’m using the Container.