[PATCH 2/5] powerpc/head fsl: move the temp 4KiB mapping to TLB0

[Kumar Gala]

On Jan 15, 2010, at 10:41 AM, Sebastian Andrzej Siewior wrote:

> From: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
> 
> Right now the setup code takes ESEL of the current mapping and puts the
> temporary into ESEL (old_ESEL & 1 ) + 1 which is either one or two.
> This is actually not required since all slots in TLB0 are invalid by now
> and can be used.
> This patch moved the temp mapping to TLB0, ESEL[0]. The invalidation of
> TLB0 does not care about IPPROT so that part can go as well.
> The benefit is that now the setup code may set every slot of TLB1 while
> before that it was not allowed to touch ESEL one or two depending on the
> old_ESEL.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
> ---
> arch/powerpc/kernel/head_fsl_booke.S |   20 +++++---------------
> 1 files changed, 5 insertions(+), 15 deletions(-)

this is problematic, we can't assume that TLB0 is safe.  It possible some other software is running on a second core and does a broadcast tlbivax which will wipe what's in TLB0.

- k