Everyone has self-knowledge. Self knowledge is the Self. They are one and the same. Sri Ramana Maharshi says in Talks, no 280:
‘There is no moment when the Self is not nor when the Self is not realised.’
‘Even now you are Self-realised.’
The problem is ignorance, meaning thinking you are the body-mind entity. Both thinking and the body-mind themselves are mere superimpositions.
When this ignorance/superimposition has been removed, then only the Self remains. That is called Self-knowledge or the Self. Sri Ramana says in Talks 462:
‘Being the Self one remains always realised, only be free from thoughts [Tom: ie. superimpositions].’
And in Talks 490:
‘The Self is always realised. But only you do not recognise the fact. The Realisation is now obscured by the present world-idea.[Tom: ie. superimposition of the body-mind-world]’
This Self-knowledge is not knowledge in the mind, which is something that comes and goes, and this Self-Knowledge is not for the body-mind at all.
It is described as being unborn and eternal by the great sages. It cannot be taught, only obstacles (ie. ignorance) is to be removed by turning within. Sri Ramana Maharshi says in Talks 282:
‘The Guru does not bring about Self-Realisation. He simply removes the obstacles to it. The Self is always realised.’
And in Talks 164:
‘Seek within. The Self is always realised.’
And talks 490 this same point above in made again, but the importance of the desire for liberation is also stated by Bhagavan:
‘The Self is always realised. The Realisation is now obscured. When the veil is removed the person feels happy at rediscovering the ever-realised Self. The ever-present Realisation appears to be a new Realisation. Now, what should one do to overcome the present ignorance. Be eager to have the true knowledge. As this eagerness grows the wrong knowledge diminishes in strength until it finally disappears.’