Re: [PATCH v2 3/4] powerpc: Add Power12 architected mode

[Mahesh J Salgaonkar <mahesh@linux.ibm.com>]

On 2026-08-04 00:47:49 Tue, Amit Machhiwal wrote:
> On 2026/08/03 09:27 PM, Mahesh Salgaonkar wrote:
> > From: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
> > 
> > PVR value of 0x0f000008 means we are arch v3.2 compliant (i.e.
> > Power12). This is used by phyp and kvm when booting as a pseries guest
> > to detect the presence of new Power12 features and to enable the
> > appropriate hwcap and facility bits.
> > 
> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> > Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
> > Signed-off-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
> > Tested-by: Praveen K Pandey <praveen@linux.ibm.com>
> > Reviewed-by: Nikhil Kumar Singh <nikhilks@linux.ibm.com>
> > ---
> >  arch/powerpc/include/asm/prom.h           |  1 +
> >  arch/powerpc/include/uapi/asm/cputable.h  |  1 +
> >  arch/powerpc/kernel/cpu_specs_book3s_64.h | 14 ++++++++++++++
> >  arch/powerpc/kernel/prom_init.c           | 12 ++++++++++--
> >  4 files changed, 26 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
> > index f4991d10d89ec..cd025c7225ee7 100644
> > --- a/arch/powerpc/include/asm/prom.h
> > +++ b/arch/powerpc/include/asm/prom.h
> > @@ -118,6 +118,7 @@ extern unsigned int boot_cpu_node_count;
> >  
> >  #define OV1_PPC_3_00		0x80	/* set if we support PowerPC 3.00 */
> >  #define OV1_PPC_3_1			0x40	/* set if we support PowerPC 3.1 */
> > +#define OV1_PPC_3_2			0x20	/* set if we support PowerPC 3.2 */
> 
> Minor: OV1_PPC_3_1 and OV1_PPC_3_2 use extra tabs relative to OV1_PPC_3_00.
> This is pre-existing style inconsistency in the file (not introduced by
> this patch) but new additions should match the surrounding code. Please
> consider aligning them.

This is bit tricky. Prior to 3.0 the ISA versions were 2.05, 2.06, 2.07
and so on and pre-existing style did make sense. But it looks like from
3.1 the style changed may be for a reason because it can not be written
as 3.10 which may create more confusiton. Hence, I plan to stick with
the new style which is introduced from 3.1.

Thanks,
-Mahesh.