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From: Michael Ellerman <mpe@ellerman.id.au>
To: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>, Christophe Leroy
 <christophe.leroy@csgroup.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>, "Aneesh Kumar K.V"
 <aneesh.kumar@kernel.org>, "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
 linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
 linux@ew.tq-group.com, Matthias Schiffer
 <matthias.schiffer@ew.tq-group.com>
Subject: Re: [PATCH] powerpc/6xx: set High BAT Enable flag on G2 cores
In-Reply-To: <20231221124538.159706-1-matthias.schiffer@ew.tq-group.com>
References: <20231221124538.159706-1-matthias.schiffer@ew.tq-group.com>
Date: Fri, 22 Dec 2023 12:16:38 +1100
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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