From: Marc Zyngier <maz@kernel.org>
To: Sumit Garg <sumit.garg@linaro.org>
Cc: catalin.marinas@arm.com, will@kernel.org,
linux-arm-kernel@lists.infradead.org, tglx@linutronix.de,
jason@lakedaemon.net, mark.rutland@arm.com,
julien.thierry.kdev@gmail.com, dianders@chromium.org,
daniel.thompson@linaro.org, jason.wessel@windriver.com,
msys.mizuma@gmail.com, ito-yuichi@fujitsu.com,
kgdb-bugreport@lists.sourceforge.net,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 5/5] arm64: ipi_nmi: Add support for NMI backtrace
Date: Mon, 19 Oct 2020 13:20:41 +0100 [thread overview]
Message-ID: <d4a4a37b93f34da79b87519181bffb97@kernel.org> (raw)
In-Reply-To: <1602673931-28782-6-git-send-email-sumit.garg@linaro.org>
On 2020-10-14 12:12, Sumit Garg wrote:
> Enable NMI backtrace support on arm64 using IPI turned as an NMI
> leveraging pseudo NMIs support. It is now possible for users to get a
> backtrace of a CPU stuck in hard-lockup using magic SYSRQ.
>
> Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> ---
> arch/arm64/include/asm/irq.h | 6 ++++++
> arch/arm64/kernel/ipi_nmi.c | 12 +++++++++++-
> 2 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/irq.h
> b/arch/arm64/include/asm/irq.h
> index b2b0c64..e840bf1 100644
> --- a/arch/arm64/include/asm/irq.h
> +++ b/arch/arm64/include/asm/irq.h
> @@ -6,6 +6,12 @@
>
> #include <asm-generic/irq.h>
>
> +#ifdef CONFIG_SMP
> +extern void arch_trigger_cpumask_backtrace(const cpumask_t *mask,
> + bool exclude_self);
> +#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
> +#endif
> +
> struct pt_regs;
>
> static inline int nr_legacy_irqs(void)
> diff --git a/arch/arm64/kernel/ipi_nmi.c b/arch/arm64/kernel/ipi_nmi.c
> index e0a9e03..e1dc19d 100644
> --- a/arch/arm64/kernel/ipi_nmi.c
> +++ b/arch/arm64/kernel/ipi_nmi.c
> @@ -9,6 +9,7 @@
> #include <linux/interrupt.h>
> #include <linux/irq.h>
> #include <linux/kgdb.h>
> +#include <linux/nmi.h>
> #include <linux/smp.h>
>
> #include <asm/nmi.h>
> @@ -25,12 +26,21 @@ void arch_send_call_nmi_func_ipi_mask(cpumask_t
> *mask)
> __ipi_send_mask(ipi_desc, mask);
> }
>
> +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool
> exclude_self)
> +{
> + nmi_trigger_cpumask_backtrace(mask, exclude_self,
> + arch_send_call_nmi_func_ipi_mask);
> +}
> +
> static irqreturn_t ipi_nmi_handler(int irq, void *data)
> {
> unsigned int cpu = smp_processor_id();
>
> - ipi_kgdb_nmicallback(cpu, get_irq_regs());
> + if (nmi_cpu_backtrace(get_irq_regs()))
> + goto out;
>
> + ipi_kgdb_nmicallback(cpu, get_irq_regs());
> +out:
> return IRQ_HANDLED;
> }
Can't you have *both* a request for a backtrace and a KGDB call?
It really shouldn't be either/or. It also outlines how well shared
interrupts work with edge triggered signalling...
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2020-10-19 12:20 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-14 11:12 [PATCH v5 0/5] arm64: Add framework to turn an IPI as NMI Sumit Garg
2020-10-14 11:12 ` [PATCH v5 1/5] arm64: Add framework to turn " Sumit Garg
2020-10-15 1:15 ` Masayoshi Mizuma
2020-10-19 11:37 ` Marc Zyngier
2020-10-20 6:43 ` Sumit Garg
2020-10-20 10:08 ` Marc Zyngier
2020-10-20 11:22 ` Sumit Garg
2020-10-20 12:25 ` Daniel Thompson
2020-10-20 12:32 ` Marc Zyngier
2020-10-21 5:22 ` Sumit Garg
2020-10-21 10:27 ` Marc Zyngier
2020-10-22 11:52 ` Sumit Garg
2020-10-19 11:56 ` Marc Zyngier
2020-10-20 7:07 ` Sumit Garg
2020-10-14 11:12 ` [PATCH v5 2/5] irqchip/gic-v3: Enable support for SGIs to act as NMIs Sumit Garg
2020-10-15 1:16 ` Masayoshi Mizuma
2020-10-19 12:07 ` Marc Zyngier
2020-10-20 7:24 ` Sumit Garg
2020-10-14 11:12 ` [PATCH v5 3/5] arm64: smp: Allocate and setup IPI as NMI Sumit Garg
2020-10-15 1:16 ` Masayoshi Mizuma
2020-10-19 11:59 ` Marc Zyngier
2020-10-20 7:16 ` Sumit Garg
2020-10-14 11:12 ` [PATCH v5 4/5] arm64: kgdb: Round up cpus using " Sumit Garg
2020-10-19 12:15 ` Marc Zyngier
2020-10-20 8:51 ` Sumit Garg
2020-10-14 11:12 ` [PATCH v5 5/5] arm64: ipi_nmi: Add support for NMI backtrace Sumit Garg
2020-10-15 1:17 ` Masayoshi Mizuma
2020-10-19 12:20 ` Marc Zyngier [this message]
2020-10-20 9:13 ` Sumit Garg
2020-10-21 10:32 ` Marc Zyngier
2020-10-21 11:28 ` Sumit Garg
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