Discrepancy in BAT mapping?

[Benjamin Herrenschmidt]

>
>Hmmm, setting the G bit for instruction pages should never be necessary.
>I may be totally wrong, but as I see the logic, your instructions are
>not supposed to modify themselves when read. So there is no reason to
>protect them from speculative access. Hence, clear the G bit on all
>instruction-only mappings, so speculative access may be used to a
>performance advantage.

Well, who will ever execute code out of the framebuffer anyway ? Also, I
beleive we can remove the G bit completely, there's no need to prevent
speculative access to the fb. I'll look into this.

Ben.


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