On Tue 2022-05-17 13:42:06, Guilherme G. Piccoli wrote: > On 17/05/2022 10:57, Petr Mladek wrote: > >> Disagree here, I'm CCing Florian for information. > >> > >> This notifier preserves RAM so it's *very interesting* if we have > >> kmsg_dump() for example, but maybe might be also relevant in case kdump > >> kernel is configured to store something in a persistent RAM (then, > >> without this notifier, after kdump reboots the system data would be lost). > > > > I see. It is actually similar problem as with > > drivers/firmware/google/gsmi.c. > > > > I does similar things like kmsg_dump() so it should be called in > > the same location (after info notifier list and before kdump). > > > > A solution might be to put it at these notifiers at the very > > end of the "info" list or make extra "dump" notifier list. > > Here I still disagree. I've commented in the other response thread > (about Google gsmi) about the semantics of the hypervisor list, but > again: this list should contain callbacks that > > (a) Should run early, _by default_ before a kdump; > (b) Communicate with the firmware/hypervisor in a "low-risk" way; > > Imagine a scenario where users configure kdump kernel to save something > in a persistent form in DRAM - it'd be like a late pstore, in the next > kernel. This callback enables that, it's meant to inform FW "hey, panic > happened, please from now on don't clear the RAM in the next FW-reboot". > I don't see a reason to postpone that - let's see if the maintainers > have an opinion. I have answered this in more detail in the other reply, see https://lore.kernel.org/r/YoShZVYNAdvvjb7z@alley I agree that both notifiers in drivers/soc/bcm/brcmstb/pm/pm-arm.c drivers/firmware/google/gsmi.c better fit into the hypervisor list after all. Best Regards, Petr
