As long as you have all your datafiles and control files from a valid cold backup, you can open your database with the resetlogs if you don't have the log files. However since resetlogs is only valid after a recovery, you have to fake one.

svrmgrl> startup mount
svrmgrl> alter database recover until cancel; -- says statement processed
svrmgrl> alter database recover cancel; -- says recovery hasn't started
svrmgrl> alter database open resetlogs;

As long as it's a valid cold backup, and you don't need any data from online logs or archived logs, you won't lose anything.