[PATCH 4/5] powerpc: Define config option for processors without broadcast TLBIE

[Paul Mackerras]

On Wed, Jan 29, 2025 at 04:14:25PM +1000, Nicholas Piggin wrote:
> On Wed Jan 29, 2025 at 8:53 AM AEST, Paul Mackerras wrote:
> > Power ISA v3.1 implementations in the Linux Compliancy Subset and
> > lower are not required to implement broadcast TLBIE, and in fact
> > Microwatt doesn't.  To avoid the need to specify "disable_tlbie" on
> > the kernel command line on SMP Microwatt systems, this defines a
> > config option that asserts that broadcast TLBIE should never be used
> > (the kernel will instead use IPIs to trigger local TLBIEs on other
> > CPUs when required).
> >
> > Signed-off-by: Paul Mackerras <paulus at ozlabs.org>
> > ---
> >  arch/powerpc/mm/book3s64/pgtable.c       | 10 ++++++++--
> >  arch/powerpc/platforms/Kconfig.cputype   | 12 ++++++++++++
> >  arch/powerpc/platforms/microwatt/Kconfig |  1 +
> >  3 files changed, 21 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
> > index 374542528080..14ee96e2a581 100644
> > --- a/arch/powerpc/mm/book3s64/pgtable.c
> > +++ b/arch/powerpc/mm/book3s64/pgtable.c
> > @@ -588,10 +588,16 @@ int pmd_move_must_withdraw(struct spinlock *new_pmd_ptl,
> >  }
> >  #endif
> >  
> > +#ifndef CONFIG_PPC_RADIX_NO_BROADCAST_TLBIE
> 
> Hate to bikeshed, but would it be annoying to make this an affirmative
> option?

I guess we'd have to make all the platforms that do have broadcast
tlbie (and a book3s-64 MMU with radix) select that option.  Which
would be powernv and pseries, I would think.  If that's correct then
it's probably not too annoying.  Should I do that in v2?

Paul.