Re: [PATCH v4 5/7] Watchdog: introduce ARM SBSA watchdog driver

From: Catalin Marinas
Date: Mon Sep 14 2015 - 04:51:48 EST


On Thu, Sep 10, 2015 at 06:45:17PM -0400, Jon Masters wrote:
> On 06/03/2015 02:53 PM, Timur Tabi wrote:
> > On 06/03/2015 01:25 PM, Guenter Roeck wrote:
> >> In general the idea here would be to use a crashdump kernel, which,
> >> when loaded, would reset the watchdog before it fires. This kernel
> >> would then write a core dump to a specified location.
> >
> > What is the mechanism for resetting the watchdog? The only code that
> > knows about the hardware registers is this driver. Does the crashdump
> > kernel call the watchdog stop function?
> >
> >> If arm64 doesn't support a crashdump kernel, it might still be possible
> >> to log the backtrace somewhere (eg in nvram using pstore if that is
> >> supported via acpi or efi).
>
> Just to go back and explicitly answer this, arm64 does have support for
> crashdump, using the standard kexec/kdump approach, exactly as on x86.

Just a clarification - this is not (yet) supported in mainline, not even
with DT.

--
Catalin

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