linux-kernel - Re: [PATCH] arm: make kexec depend on MMU

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Message-ID: <20200205235327.GV25745@shell.armlinux.org.uk>
Date:   Wed, 5 Feb 2020 23:53:27 +0000
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Stefan Agner <stefan@...er.ch>
Cc:     arnd@...db.de, linus.walleij@...aro.org, akpm@...ux-foundation.org,
        nsekhar@...com, mchehab+samsung@...nel.org,
        bgolaszewski@...libre.com, armlinux@...isordat.com,
        benjamin.gaignard@...aro.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Michal Hocko <mhocko@...e.com>
Subject: Re: [PATCH] arm: make kexec depend on MMU

Does patch 8951/1, which has been merged into mainline, not fix this?

On Wed, Feb 05, 2020 at 11:43:44PM +0100, Stefan Agner wrote:
> From: Michal Hocko <mhocko@...e.com>
> 
> arm nommu config with KEXEC enabled doesn't compile
> arch/arm/kernel/setup.c: In function 'reserve_crashkernel':
> arch/arm/kernel/setup.c:1005:25: error: 'SECTION_SIZE' undeclared (first
> use in this function)
>              crash_size, SECTION_SIZE);
> 
> since 61603016e212 ("ARM: kexec: fix crashkernel= handling") which is
> over one year without anybody noticing. I have only noticed beause of
> my testing nommu config which somehow gained CONFIG_KEXEC without
> an intention. This suggests that nobody is actually using KEXEC
> on nommu ARM configs. It is even a question whether kexec works with
> nommu.
> 
> Make KEXEC depend on MMU to make this clear. If somebody wants to enable
> there will be probably more things to take care.
> 
> Signed-off-by: Michal Hocko <mhocko@...e.com>
> Reviewed-by: Stefan Agner <stefan@...er.ch>
> Signed-off-by: Stefan Agner <stefan@...er.ch>
> ---
>  arch/arm/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 96dab76da3b3..59ce8943151f 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1906,6 +1906,7 @@ config KEXEC
>  	bool "Kexec system call (EXPERIMENTAL)"
>  	depends on (!SMP || PM_SLEEP_SMP)
>  	depends on !CPU_V7M
> +	depends on MMU
>  	select KEXEC_CORE
>  	help
>  	  kexec is a system call that implements the ability to shutdown your
> -- 
> 2.25.0
> 
> 

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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