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.