# Simon Burge 2006-11-26:
> Jachym Holecek wrote:
> > # Jachym Holecek 2006-10-31:
> > > The patch below changes evbppc to map just 0 upto endkernel to make sure
> > > the trap code has everything it could possibly need. Looks OK to commit?
> > 
> > As Simon noted, this is wrong, we must map console/devices after
> > (vaddr_t)roundup(physmem, 16MB) so that pmap_tlbmiss() continues
> > to work. Updated patch below, does it look OK this time?
> 
> You patch wedged my Walnut pretty much straight away.  I've tracked this
> down to:

Oops, sorry :-(. Fortunately, I've recently ordered a 405GPr evaluation
board, so I'll have a testing platform handy in a few weeks (my Virtex is
mostly in the HW department these days).

> +       if (ctx != KERNEL_PID || (va < ctob((vaddr_t)physmem))) {
> 
> The "va < ctob(...)" should be "va >= ctob(...)".  That said, I think
> I'd prefer to commit something like:
> 
>         if (ctx != KERNEL_PID || (va >= VM_MIN_KERNEL_ADDRESS)) {
> 
> My reasoning is: 
> 
>  - There will be never be a kernel VA less than VM_MIN_KERNEL_ADDRESS.
> 
>  - This saves a load of the physmem variable and an instruction or two
>    of arithmetic in a critical path.
> 
> Sound good?

Fine with me. That's a lot how the code used to work ~forever, except
testing against VM_MIN_KERNEL_ADDRESS is more readable than a numeric
constant.

> With this change, the rest of your patch (all the evbppc parts)
> works.

Commited, thanks for the review.

	-- Jachym