Here are some quotes from the Satipatthana Sutta (Establishment of Mindfulness):
"There is the case where a monk remains focused on mental qualities in & of themselves with reference to the five hindrances. And how does a monk remain focused on mental qualities in & of themselves with reference to the five hindrances? There is the case where, there being sensual desire present within, a monk discerns that 'There is sensual desire present within me.' Or, there being no sensual desire present within, he discerns that 'There is no sensual desire present within me.' He discerns how there is the arising of unarisen sensual desire. And he discerns how there is the abandoning of sensual desire once it has arisen. And he discerns how there is no future arising of sensual desire that has been abandoned. (The same formula is repeated for the remaining hindrances: ill will, sloth & drowsiness, restlessness & anxiety, and uncertainty.)
This is in line with being mindful about greed, hatred, and delusion... and their abandoning.
"Furthermore, the monk remains focused on mental qualities in & of themselves with reference to the seven factors for Awakening. And how does he remain focused on mental qualities in & of themselves with reference to the seven factors for Awakening? There is the case where, there being mindfulness as a factor for Awakening present within, he discerns that 'Mindfulness as a factor for Awakening is present within me.' Or, there being no mindfulness as a factor for Awakening present within, he discerns that 'Mindfulness as a factor for Awakening is not present within me.' He discerns how there is the arising of unarisen mindfulness as a factor for Awakening. And he discerns how there is the culmination of the development of mindfulness as a factor for Awakening once it has arisen. (The same formula is repeated for the remaining factors for Awakening: analysis of qualities, persistence, rapture, serenity, concentration, & equanimity.)
How do you discern the "Mindfulness as a factor for Awakening is
not present within me," if you were not mindful in the first place?
"Furthermore, the monk remains focused on mental qualities in & of themselves with reference to the four noble truths. And how does he remain focused on mental qualities in & of themselves with reference to the four noble truths? There is the case where he discerns, as it has come to be, that 'This is stress.' He discerns, as it has come to be, that 'This is the origination of stress.' He discerns, as it has come to be, that 'This is the cessation of stress.' He discerns, as it has come to be, that 'This is the way leading to the cessation of stress.'
"'This is the direct path for the purification of beings, for the overcoming of sorrow & lamentation, for the disappearance of pain & distress, for the attainment of the right method, & for the realization of Unbinding — in other words, the four frames of reference.' Thus was it said, and in reference to this was it said."