[PATCH 03/15] ARM: rework ARM11 CPU selection logic

[Linus Walleij]

On Wed, Dec 4, 2024 at 11:29 AM Arnd Bergmann <arnd at kernel.org> wrote:

> From: Arnd Bergmann <arnd at arndb.de>
>
> Support for SMP on ARM1136r0 has been broken for a while, and nobody
> is working on fixing it. I had a plan to change ARMv6 support to no
> longer coexist in a common kernel with ARMv7 CPUs but instead ARMv5 and
> below. This would have addressed the problem, but after a recent mailing
> list discussion, we concluded that an easier approach is to just forbid
> ARM1136r0 CPU support on SMP-enabled kernels.
>
> This mainly affects users of the Nokia N800/N810 tablets using an
> OMAP2420 SoC, which is the only commercial product with an ARM1136r0
> that is still supported by the kernel.
>
> The other machines that are still in the same hardware catogory are:
>
>  - TI OMAP2420 H4 reference board
>  - TI OMAP2430 SDP software development platform
>  - Freescale/NXP i.MX31 Lite Development Kit
>  - Buglabs i.MX31 Bug 1.x prototype
>  - Arm Integrator/AP with CM1136JF-S core module
>
> To my knowledge, none of these have any actual users aside from
> reference boards being used more easily test the platforms.
>
> There are also a few ARM1136r1 machines, which implement the
> ARMv6K SMP support (barriers, atomics and TLS):
>
>  - Eukrea CPUIMX35 reference platform
>  - Freescale/NXP i.MX35 Product Development Kit
>  - ARM Integrator/CP/IM-LT3 with ARM1136J Core Tile

I can't test that, I doubt anyone can. I think this support can
be simply deleted unless there is some QEMU support or
so.

>  - ARM Realview/EB with ARM1136J Core Tile

I will check if I have this one, otherwise this can probably go
as well.

>  arch/arm/mach-versatile/Kconfig | 10 +++++-----

For Versatile:
Acked-by: Linus Walleij <linus.walleij at linaro.org>

Yours,
Linus Walleij