You've learned Wall Jump! To use this ability, push the Thumbstick toward a wall and press A continuously to leap upward!
Wall Jump is the second skill Ori learns, and the first skill to be had from an Ancestral Tree. Passed on to Ori by the light of Fil, it allows the young spirit to jump up and off of walls, and enables access to areas that cannot be reached by a single jump alone. It is essential to exploring Nibel.
The Ancestral Tree for Wall Jump is found deep within the Sunken Glades.