Re: [PATCH] powerpc/6xx: set High BAT Enable flag on G2 cores

Michael Ellerman
2023-12-22T01:16:40Z

Matthias Schiffer <matthias.schiffer@ew.tq-group.com> writes:
> MMU_FTR_USE_HIGH_BATS is set for G2-based cores (G2_LE, e300cX), but the
> high BATs need to be enabled in HID2 to work. Add register definitions
> and introduce a G2 variant of __setup_cpu_603.
>
> This fixes boot on CPUs like the MPC5200B with STRICT_KERNEL_RWX enabled.

Nice find.

Minor nit on naming. The 32-bit code mostly uses the numeric names, eg.
603, 603e, 604 etc. Can we stick with that, rather than using "G2"?

Wikipedia says G2 == 603e. But looking at your patch you're not changing
all the 603e cores, so I guess it's not that clear cut?

If using "G2" makes the most sense then it would be nice to update
Documentation/arch/powerpc/cpu_families.rst to mention it (not asking
you to do it necessarily, more a note for us).

cheers