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From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Tue, 27 Feb 2024 09:54:46 +0100
Message-ID: <CAMuHMdWRBQF95fJ+NkPUdvpu5VfRm2WyTnvdqB1Xe7d4vsvY2g@mail.gmail.com>
Subject: Re: [PATCH 3/4] arch: define CONFIG_PAGE_SIZE_*KB on all architectures
To: Arnd Bergmann <arnd@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, Vincenzo Frascino <vincenzo.frascino@arm.com>, 
	Kees Cook <keescook@chromium.org>, Anna-Maria Behnsen <anna-maria@linutronix.de>, 
	Arnd Bergmann <arnd@arndb.de>, Matt Turner <mattst88@gmail.com>, Vineet Gupta <vgupta@kernel.org>, 
	Russell King <linux@armlinux.org.uk>, Catalin Marinas <catalin.marinas@arm.com>, 
	Guo Ren <guoren@kernel.org>, Brian Cain <bcain@quicinc.com>, 
	Huacai Chen <chenhuacai@kernel.org>, Michal Simek <monstr@monstr.eu>, 
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>, Helge Deller <deller@gmx.de>, 
	Michael Ellerman <mpe@ellerman.id.au>, Christophe Leroy <christophe.leroy@csgroup.eu>, 
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	John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>, Andreas Larsson <andreas@gaisler.com>, 
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Hi Arnd,

On Mon, Feb 26, 2024 at 5:15=E2=80=AFPM Arnd Bergmann <arnd@kernel.org> wro=
te:
> From: Arnd Bergmann <arnd@arndb.de>
>
> Most architectures only support a single hardcoded page size. In order
> to ensure that each one of these sets the corresponding Kconfig symbols,
> change over the PAGE_SHIFT definition to the common one and allow
> only the hardware page size to be selected.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Thanks for your patch!

> --- a/arch/m68k/Kconfig
> +++ b/arch/m68k/Kconfig
> @@ -84,12 +84,15 @@ config MMU
>
>  config MMU_MOTOROLA
>         bool
> +       select HAVE_PAGE_SIZE_4KB
>
>  config MMU_COLDFIRE
> +       select HAVE_PAGE_SIZE_8KB

I think you can do without this...

>         bool
>
>  config MMU_SUN3
>         bool
> +       select HAVE_PAGE_SIZE_8KB
>         depends on MMU && !MMU_MOTOROLA && !MMU_COLDFIRE
>
>  config ARCH_SUPPORTS_KEXEC
> diff --git a/arch/m68k/Kconfig.cpu b/arch/m68k/Kconfig.cpu
> index 9dcf245c9cbf..c777a129768a 100644
> --- a/arch/m68k/Kconfig.cpu
> +++ b/arch/m68k/Kconfig.cpu
> @@ -30,6 +30,7 @@ config COLDFIRE
>         select GENERIC_CSUM
>         select GPIOLIB
>         select HAVE_LEGACY_CLK
> +       select HAVE_PAGE_SIZE_8KB if !MMU

... if you would drop the !MMU-dependency here.

>
>  endchoice
>
> @@ -45,6 +46,7 @@ config M68000
>         select GENERIC_CSUM
>         select CPU_NO_EFFICIENT_FFS
>         select HAVE_ARCH_HASH
> +       select HAVE_PAGE_SIZE_4KB

Perhaps replace this by

    config M68KCLASSIC
            bool "Classic M68K CPU family support"
            select HAVE_ARCH_PFN_VALID
  +         select HAVE_PAGE_SIZE_4KB if !MMU

so it covers all 680x0 CPUs without MMU?

>         select LEGACY_TIMER_TICK
>         help
>           The Freescale (was Motorola) 68000 CPU is the first generation =
of

Gr{oetje,eeting}s,

                        Geert

--=20
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k=
org

In personal conversations with technical people, I call myself a hacker. Bu=
t
when I'm talking to journalists I just say "programmer" or something like t=
hat.
                                -- Linus Torvalds