Here's the bass tab for "Kashmir". The tuning's regular.
[ Tab from: https://www.guitartabs.cc/tabs/l/led_zeppelin/kashmir_btab_ver_3.html ]
G|---------------------------------------------------------
D|777-0-777-0-888-0-888-0-999-0-999-0-10-10-10-0-10-10-10-0
A|---------------------------------------------------------
E|---------------------------------------------------------
G|---------
D|12-12-12-
A|---------
E|---------
That's it. Just keep repeating this little riff. But on the second time around, only do
one "777" and then go to the 8th fret.