linux-kernel - Re: [PATCH 2/2] ARM: shmobile: only call secure_cntvoff

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Date:   Fri, 25 May 2018 21:12:57 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     arm@...nel.org, Simon Horman <horms@...ge.net.au>,
        Magnus Damm <magnus.damm@...il.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Mylène Josserand <mylene.josserand@...tlin.com>,
        Biju Das <biju.das@...renesas.com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] ARM: shmobile: only call secure_cntvoff_init on SMP builds

Hi Arnd,

On Fri, May 25, 2018 at 6:10 PM, Arnd Bergmann <arnd@...db.de> wrote:
> The secure_cntvoff_init() function is not available without CONFIG_SMP,
> leading to a link error on shmobile:
>
> arch/arm/mach-shmobile/setup-rcar-gen2.o: In function `rcar_gen2_timer_init':
> setup-rcar-gen2.c:(.init.text+0x18): undefined reference to `secure_cntvoff_init'
>
> From the description in commit 3fd45a136ff6 ("ARM: shmobile: rcar-gen2:
> Make sure CNTVOFF is initialized on CA7/15"), I understand that we
> don't need to call it on non-SMP builds because the boot CPU is always
> initialized by common code, so we can simply avoid the reference by
> checking for CONFIG_SMP.
>
> Fixes: cad160ed0a94 ("ARM: shmobile: Convert file to use cntvoff")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

NAKed-by: Geert Uytterhoeven <geert+renesas@...der.be>

> --- a/arch/arm/mach-shmobile/setup-rcar-gen2.c
> +++ b/arch/arm/mach-shmobile/setup-rcar-gen2.c
> @@ -71,7 +71,8 @@ void __init rcar_gen2_timer_init(void)
>         void __iomem *base;
>         u32 freq;
>
> -       secure_cntvoff_init();
> +       if (IS_ENABLED(CONFIG_SMP))
> +               secure_cntvoff_init();

The call here is for the boot CPU, since commit 9ce3fa6816c2fb59 ("ARM:
shmobile: rcar-gen2: Add CA7 arch_timer initialization for r8a7794"), and
modified and consolidated in commit 3fd45a136ff6 mentioned above.

The call for secondary CPUs is in arch/arm/mach-shmobile/headsmp-apmu.S.

>
>         if (of_machine_is_compatible("renesas,r8a7745") ||
>             of_machine_is_compatible("renesas,r8a77470") ||

So the proper fix is to build arch/arm/common/secure_cntvoff.o
unconditionally.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds