WordPress: Getting "Newer Posts" and "Older Posts" links on a Specialized Page Template

WordPress: Getting "Newer Posts" and "Older Posts" links on a Specialized
Page Template

I am using a Specialized Page Template to display list of posts. I am
using the following code for that:
<?php
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
$args = array(
'paged' => $paged
);
$all_posts = get_posts($args);
?>
<?php foreach ( $all_posts as $post ) : setup_postdata( $post ); ?>
/* the loop */
<?php endforeach; ?>
Now I want to put "Newer Posts" and "Older Posts" links below it.
next_posts_link() and previous_posts_link() prints nothing here. How can I
add these two links on this page?