Hi Jon, On 11 September 2015 at 06:45, Jon Masters <jcm@xxxxxxxxxx> 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. > There's still some more work to be done to get the ACPI case fully > upstream (e.g. on X-Gene platforms such as the HP ProLiant Moonshot m400 > we need non-PSCI CPU parking protocol offlining when booting in > UEFI/ACPI mode), but it's what we are doing in RHEL(SA) and the goal is > to help clean up the remaining pieces upstream there. Great thanks for your info. I have tried kexec/kdump on a real aarch64 hardware, that works well. Although it's still under development and upstreaming, the support is there. After discussing with some kexec/kdump developer, I think this driver can cooperate with kexec/kdump. > > Jon. > -- Best regards, Fu Wei Software Engineer Red Hat Software (Beijing) Co.,Ltd.Shanghai Branch Ph: +86 21 61221326(direct) Ph: +86 186 2020 4684 (mobile) Room 1512, Regus One Corporate Avenue,Level 15, One Corporate Avenue,222 Hubin Road,Huangpu District, Shanghai,China 200021 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
