location ~ ^.+\.php {
  (...)
  fastcgi_split_path_info ^((?U).+\.php)(/?.+)$;
  fastcgi_param SCRIPT_FILENAME /path/to/php$fastcgi_script_name;
  fastcgi_param PATH_INFO $fastcgi_path_info;
  fastcgi_param PATH_TRANSLATED $document_root$fastcgi_path_info;
  (...)
}