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From:   Doug Anderson <dianders@chromium.org>
Date:   Wed, 21 Jun 2023 16:50:12 -0700
Message-ID: <CAD=FV=XgC0JkjMZjx0z-gt0iXp-UJr87nutB9xWKhB6qMzWWNg@mail.gmail.com>
Subject: Re: [PATCH v2 6/6] watchdog/hardlockup: Define HARDLOCKUP_DETECTOR_ARCH
To:     Michael Ellerman <mpe@ellerman.id.au>
Cc:     Petr Mladek <pmladek@suse.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kgdb-bugreport@lists.sourceforge.net, linux-kernel@vger.kernel.org,
        Nicholas Piggin <npiggin@gmail.com>,
        linuxppc-dev@lists.ozlabs.org,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        sparclinux@vger.kernel.org,
        "David S . Miller" <davem@davemloft.net>,
        linux-perf-users@vger.kernel.org
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Hi,

On Wed, Jun 21, 2023 at 6:08=E2=80=AFAM Michael Ellerman <mpe@ellerman.id.a=
u> wrote:
>
> Petr Mladek <pmladek@suse.com> writes:
> > The HAVE_ prefix means that the code could be enabled. Add another
> > variable for HAVE_HARDLOCKUP_DETECTOR_ARCH without this prefix.
> > It will be set when it should be built. It will make it compatible
> > with the other hardlockup detectors.
> >
> > The change allows to clean up dependencies of PPC_WATCHDOG
> > and HAVE_HARDLOCKUP_DETECTOR_PERF definitions for powerpc.
> >
> > As a result HAVE_HARDLOCKUP_DETECTOR_PERF has the same dependencies
> > on arm, x86, powerpc architectures.
> >
> > Signed-off-by: Petr Mladek <pmladek@suse.com>
> > Reviewed-by: Douglas Anderson <dianders@chromium.org>
> > ---
> >  arch/powerpc/Kconfig | 5 ++---
> >  include/linux/nmi.h  | 2 +-
> >  lib/Kconfig.debug    | 9 +++++++++
> >  3 files changed, 12 insertions(+), 4 deletions(-)
>
> Something in this patch is breaking the powerpc g5_defconfig, I don't
> immediately see what though.
>
> ../arch/powerpc/kernel/stacktrace.c: In function =E2=80=98handle_backtrac=
e_ipi=E2=80=99:
> ../arch/powerpc/kernel/stacktrace.c:171:9: error: implicit declaration of=
 function =E2=80=98nmi_cpu_backtrace=E2=80=99 [-Werror=3Dimplicit-function-=
declaration]
>   171 |         nmi_cpu_backtrace(regs);
>       |         ^~~~~~~~~~~~~~~~~
> ../arch/powerpc/kernel/stacktrace.c: In function =E2=80=98arch_trigger_cp=
umask_backtrace=E2=80=99:
> ../arch/powerpc/kernel/stacktrace.c:226:9: error: implicit declaration of=
 function =E2=80=98nmi_trigger_cpumask_backtrace=E2=80=99; did you mean =E2=
=80=98arch_trigger_cpumask_backtrace=E2=80=99? [-Werror=3Dimplicit-function=
-declaration]
>   226 |         nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_b=
acktrace_ipi);
>       |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>       |         arch_trigger_cpumask_backtrace
> cc1: all warnings being treated as errors

Yeah, I can reproduce that.

The problem is that before ${SUBJECT} patch "include/linux/nmi.h"
would include <asm/nmi.h>. Now it won't.

There are a ton of different ways to fix this, but I think the one
that makes sense is to be consistent with other architectures and move
the "arch_trigger_cpumask_backtrace" definitions to asm/irq.h.

https://lore.kernel.org/r/20230621164809.1.Ice67126857506712559078e7de26d32=
d26e64631@changeid

-Doug