On Fri, 2020-03-27 at 16:12 +0100, Christophe Leroy wrote:
>
> Le 27/03/2020 à 10:03, Balamuruhan S a écrit :
> > On Fri, 2020-03-27 at 07:48 +0100, Christophe Leroy wrote:
> > > Le 26/03/2020 à 07:15, Balamuruhan S a écrit :
> > > > Data Cache Block Invalidate (dcbi) instruction was implemented back in
> > > > PowerPC
> > > > architecture version 2.03. It is obsolete and attempt to use of this
> > > > illegal
> > > > instruction results in a hypervisor emulation assistance interrupt. So,
> > > > ifdef
> > > > it out the option `i` in xmon for 64bit Book3S.
> > >
> > > I don't understand. You say two contradictory things:
> > > 1/ You say it _was_ added back.
> > > 2/ You say it _is_ obsolete.
> > >
> > > How can it be obsolete if it was added back ?
> >
> > I actually learnt it from P8 and P9 User Manual,
> >
> > The POWER8/POWER9 core does not provide support for the following optional
> > or
> > obsolete instructions (attempted use of these results in a hypervisor
> > emulation
> > assistance interrupt):
> > • tlbia - TLB invalidate all
> > • tlbiex - TLB invalidate entry by index (obsolete)
> > • slbiex - SLB invalidate entry by index (obsolete)
> > • dcba - Data cache block allocate (Book II; obsolete)
> > • dcbi - Data cache block invalidate (obsolete)
> > • rfi - Return from interrupt (32-bit; obsolete)
> >
>
> Then that's exactly what you have to say in the coming log.
Sure, I will change the commit log in next version along with your suggested
way to ifdef.
>
> Maybe you could also change invalidate_dcache_range():
>
> for (i = 0; i < size >> shift; i++, addr += bytes) {
> if (IS_ENABLED(CONFIG_PPC_BOOK3S_64))
> dcbf(addr);
> else
> dcbi(addr);
> }
I will leave this as is based on the discussion.
Thank you Christophe and Segher.
-- Bala
>
>
>
>
> Christophe
