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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

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

Matthias Schiffer <matthias.schiffer@...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