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References: <20230601213440.2488667-1-dianders@chromium.org> <20230601143109.v9.6.Ia3aeac89bb6751b682237e76e5ba594318e4b1aa@changeid>
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From:   Doug Anderson <dianders@chromium.org>
Date:   Thu, 15 Jun 2023 11:14:18 -0700
Message-ID: <CAD=FV=XbnUZh2uQ5Sr3Dg=+Kiz7rfZVyP-zNQtXrV_NSsCTFcA@mail.gmail.com>
Subject: Re: [PATCH v9 6/7] kgdb: Provide a stub kgdb_nmicallback() if !CONFIG_KGDB
To:     Mark Rutland <mark.rutland@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Sumit Garg <sumit.garg@linaro.org>,
        Daniel Thompson <daniel.thompson@linaro.org>,
        Marc Zyngier <maz@kernel.org>
Cc:     linux-perf-users@vger.kernel.org, ito-yuichi@fujitsu.com,
        Chen-Yu Tsai <wens@csie.org>, Ard Biesheuvel <ardb@kernel.org>,
        Stephen Boyd <swboyd@chromium.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-arm-kernel@lists.infradead.org,
        kgdb-bugreport@lists.sourceforge.net,
        Masayoshi Mizuma <msys.mizuma@gmail.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        Lecopzer Chen <lecopzer.chen@mediatek.com>,
        Jason Wessel <jason.wessel@windriver.com>,
        linux-kernel@vger.kernel.org
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Daniel,

On Thu, Jun 1, 2023 at 2:37=E2=80=AFPM Douglas Anderson <dianders@chromium.=
org> wrote:
>
> To save architectures from needing to wrap the call in #ifdefs, add a
> stub no-op version of kgdb_nmicallback(), which returns 1 if it didn't
> handle anything.
>
> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
> In v9 this is the only kgdb dependency. I'm assuming it could go
> through the arm64 tree? If that's not a good idea, we could always
> change the patch ("arm64: kgdb: Roundup cpus using IPI as NMI") not to
> depend on it by only calling kgdb_nmicallback() if CONFIG_KGDB is not
> defined.
>
> Changes in v9:
> - Added missing "inline"
>
> Changes in v8:
> - "Provide a stub kgdb_nmicallback() if !CONFIG_KGDB" new for v8
>
>  include/linux/kgdb.h | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
> index 258cdde8d356..76e891ee9e37 100644
> --- a/include/linux/kgdb.h
> +++ b/include/linux/kgdb.h
> @@ -365,5 +365,6 @@ extern void kgdb_free_init_mem(void);
>  #define dbg_late_init()
>  static inline void kgdb_panic(const char *msg) {}
>  static inline void kgdb_free_init_mem(void) { }
> +static inline int kgdb_nmicallback(int cpu, void *regs) { return 1; }

What do you think about landing just ${SUBJECT} patch in kgdb right
now so it can end up in v6.5-rc1? It seems like this series is
currently blocked on Mark getting a spare moment and it seems unlikely
that'll happen this cycle. If we at least land the kgdb patch then it
would make things all that much easier to land in the next cycle. The
kgdb patch feels like it can make sense on its own...

-Doug