Re: NetBSD ppc64 & ppc64le support?

[Greg Troxel <gdt%lexort.com@localhost>]

Chris Hanson <cmhanson%eschatologist.net@localhost> writes:

> On May 7, 2025, at 3:54 PM, Greg Troxel <gdt%lexort.com@localhost> wrote:
>> 
>> Chris Hanson <cmhanson%eschatologist.net@localhost> writes:
>> 
>>> NetBSD appears to use the powerpc architecture name like FreeBSD but the eb/el suffixes like Linux, so my first inclination is that the NetBSD architecture names would be powerpc64 and powerpc64el.
>> 
>> If you mean "should we change the code to align with X", idk.
>> 
>> If you are asking "how are things now", then read build.sh.
>
> Thanks, looks like the MACHINE_ARCH is referred to as powerpc64 in build.sh so that’s what should probably be kept to so changes are minimally invasive.
>
> It also looks like there’s already a GENERIC64 kernel config for ofppc so maybe a different machine isn’t needed?

There are more or less three layers, and beware I'm a little fuzzy;

  MACHINE_ARCH which is equal to CPU type in that for a userland
  program across NetBSD, you just need the same MACHINE_ARCH.

  MACHINE is about more than just the CPU type, how you deal with the hardware.

  then there is a kernel for specific hardware, and if it's reasonable
  to have one MACHINE for a group of hardware types, with different
  kernels, we do.  And if the same kernel can run on multiple hardware
  types, even better.

A good example of this grouping is evbarm which has a ton of boards, but
they are all close enough.  And some have separate kernels and multiple
different boards can run GENERIC.

ofppc seems to be a separate MACHINE, and there is sys/arch/ofppc.  I
would guess the whole way the kernel deals with the hardware is just
different enough.

Reading build.sh, I only really see eb/el for mips.  My guess is that
there were both kinds, from not-DEC and DEC, whereas ppc is more of an
IBM thing where ~everbody uses eb.