Question regarding the DTLB Miss exceptions

[Joakim Tjernlund]

>
> I'm tracking a problem that's leading me through DSI and DTLB miss
> exceptions on an MPC8347 (e300c1 core), and I've come across an oddity
> that I'm hoping someone can explain.
>
> When a DTLB Miss exception can't find a PTE for the virtual address being
> written/read, it dummies up the SPRs for a DSI exception and then calls
> directly into the DSI exception code.  Just before the DTLB miss code
> stores a value into DSISR it sets bit 2, which for a DSI exception is a
> reserved bit and should be cleared.  There's no comment on the code
> (.../arch/powerpc/kernel/head_32.S line 619 of the 2.6.33-rc1 kernel). Can
> anyone tell me why this bit is getting set?

Probably for generic handling in do_page_fault()

  Jocke