From: Marc Zyngier <maz@kernel.org>
To: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Sumit Garg <sumit.garg@linaro.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Jason Cooper <jason@lakedaemon.net>,
Mark Rutland <mark.rutland@arm.com>,
julien.thierry.kdev@gmail.com,
Douglas Anderson <dianders@chromium.org>,
Jason Wessel <jason.wessel@windriver.com>,
Masayoshi Mizuma <msys.mizuma@gmail.com>,
ito-yuichi@fujitsu.com, kgdb-bugreport@lists.sourceforge.net,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 1/5] arm64: Add framework to turn IPI as NMI
Date: Tue, 20 Oct 2020 13:32:03 +0100 [thread overview]
Message-ID: <abe358694e06a6076fb5838d1231eee6@kernel.org> (raw)
In-Reply-To: <20201020122535.paym32gksuhcqtwq@holly.lan>
On 2020-10-20 13:25, Daniel Thompson wrote:
> On Tue, Oct 20, 2020 at 04:52:43PM +0530, Sumit Garg wrote:
[...]
>> So in general, IPI as a normal IRQ is still useful for debugging but
>> it can't debug a core which is stuck in deadlock with interrupts
>> disabled.
>>
>> And since we choose override default implementations for pseudo NMI
>> support, we need to be backwards compatible for platforms which don't
>> possess pseudo NMI support.
>
> Do the fallback implementations require a new IPI? The fallbacks
> could rely on existing mechanisms such as the smp_call_function
> family.
Indeed. I'd be worried of using that mechanism for NMIs, but normal
IPIs should stick to the normal cross-call stuff.
The jury is still out on why this is a good idea, given that it
doesn't work in the only interesting case (deadlocked CPUs).
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2020-10-20 12:32 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 [this message]
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
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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