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From: dwmw2@infradead.org (David Woodhouse)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v35 08/14] arm64: kdump: implement machine_crash_shutdown()
Date: Mon, 03 Apr 2017 10:21:34 +0100	[thread overview]
Message-ID: <1491211294.6020.21.camel@infradead.org> (raw)
In-Reply-To: <20170403022440.12515-6-takahiro.akashi@linaro.org>

On Mon, 2017-04-03 at 11:24 +0900, AKASHI Takahiro wrote:
> 
> +static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs
> *regs)
> +{
> +#ifdef CONFIG_KEXEC_CORE
> +???????crash_save_cpu(regs, cpu);
> +
> +???????atomic_dec(&waiting_for_crash_ipi);
> +
> +???????local_irq_disable();

Shouldn't the above two be the other way round? Stop handling
interrupts *before* we tell the surviving CPU that we're done?

Also, should the surviving CPU be calling __cpu_die() to attempt to
check that the others really have died? Sure, it can't do much more
than print a warning if the call to ->cpu_kill() times out, but that's
still useful information. And perhaps we could allow platforms to
register a method to shoot other CPUs down forcefully if they don't
respond. My board could apparently support that.

It would certainly be useful to allow smp_send_crash_stop() to be
overridden with a platform-specific method instead of normal IPIs. The
platform might be able to do something... less maskable.
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  reply	other threads:[~2017-04-03  9:21 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-03  2:21 [PATCH v35 00/14] arm64: add kdump support AKASHI Takahiro
2017-04-03  2:23 ` [PATCH v35 01/14] memblock: add memblock_clear_nomap() AKASHI Takahiro
2017-04-03  2:23 ` [PATCH v35 02/14] memblock: add memblock_cap_memory_range() AKASHI Takahiro
2017-04-05 17:20   ` Catalin Marinas
2017-04-03  2:24 ` [PATCH v35 03/14] arm64: limit memory regions based on DT property, usable-memory-range AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 04/14] arm64: kdump: reserve memory for crash dump kernel AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 05/14] arm64: mm: add set_memory_valid() AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 06/14] arm64: kdump: protect crash dump kernel memory AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 07/14] arm64: hibernate: preserve kdump image around hibernation AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 08/14] arm64: kdump: implement machine_crash_shutdown() AKASHI Takahiro
2017-04-03  9:21   ` David Woodhouse [this message]
2017-04-04  7:29     ` AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 09/14] arm64: kdump: add VMCOREINFO's for user-space tools AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 10/14] arm64: kdump: provide /proc/vmcore file AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 11/14] arm64: kdump: enable kdump in defconfig AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 12/14] Documentation: kdump: describe arm64 port AKASHI Takahiro
2017-04-03  2:26 ` [PATCH v35 13/14] Documentation: dt: chosen properties for arm64 kdump AKASHI Takahiro
2017-04-03  2:26 ` [PATCH v35 14/14] efi/libstub/arm*: Set default address and size cells values for an empty dtb AKASHI Takahiro
2017-05-22  0:25 ` [PATCH v35 00/14] arm64: add kdump support AKASHI Takahiro

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