Re: [v4,17/21] powerpc/8xx: set PTE bit 22 off TLBmiss

On Tue, 2014-11-18 at 21:07 +0100, christophe leroy wrote:

Le 08/11/2014 01:08, Scott Wood a écrit :

quoted

OK, so the _PAGE_KERNEL_RO(X) stuff is because initially setting the PTE
doesn't go through pte_update().

I'll apply this, though it'd be cleaner to just have 8xx versions of the
relevant PTE accessor functions to maintain the PTE the way the hardware
wants (this would also eliminate the _PAGE_RW inversion that's still in
the TLB miss handler).

Yes, I've been looking at a simple way to also eliminate the _PAGE_RW 
inversion, but i've not been able to find an easy solution up to now.

It seems that we have two functions that set PTE: set_pte_at() and 
pte_update()
I could perform the bit 22 (0x200) stuff and the _PAGE_RW invertion in 
both functions, but then there are functions that read the PTE to make 
decision based on PAGE_RW for instance.

Where?  The only relevant use of _PAGE_RW outside accessors that I see
is in gup_pte_range(), which shouldn't be too hard to fix up.

-Scott