Do we need tlbsx at finish_tlb_load?

[Paul Mackerras]

Dan Malek writes:

> An instuction TLB miss will load the TLB with a PTE that indicates it isn't
> valid.  A subsequent TLB instruction fault to load the page will cause a

If the PTE isn't valid (i.e. the _PAGE_PRESENT bit is 0) we don't put
it into the TLB.  If we did it would be ignored by the hardware and we
would get another TLB miss straight away.  I believe that on 8xx you
actually have two valid bits in each TLB entry, so you can have a TLB
entry that is "valid" but describes a non-present page.  That isn't
the case on 4xx.

Paul.

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