BIOS is part of the hardware accessing it is independent of whatever operating system you happen to have installed. In other words, that you happen to have Linux installed is not relevant to what you are trying to do.
If I don't know how to access the BIOS I normally turn the machine on then repeatedly hit F1. If that doesn't work, reboot and try F2. If that doesn't work, reboot try Delete. Usually it's one of them.
If F1 F2 or Delete don't work then Google based upon the make/model of your laptop.