On Thu, Dec 19, 2019 at 12:13:48AM +1100, Michael Ellerman wrote:

quoted

quoted

I'm a little confused though; if nohash is a software TLB fill, why do
you need a TLBI for tables?

nohash (AKA book3e) has different mmu modes. I don't follow all the 
details w.r.t book3e. Paul or Michael might be able to explain the need 
for table flush with book3e.

Some of the Book3E CPUs have a partial hardware table walker. The IBM one (A2)
did, before we ripped that support out. And the Freescale (NXP) e6500
does, see eg:

  28efc35fe68d ("powerpc/e6500: TLB miss handler with hardware tablewalk support")

They only support walking one level IIRC, ie. you can create a TLB entry
that points to a PTE page, and the hardware will dereference that to get
a PTE and load that into the TLB.

Shiny!, all the embedded goodness. Thanks for the info.