On 03/16/2017 05:45 PM, Larry Bassel wrote:
On 30 Jan 17 17:23, David Miller wrote:
From: Larry Bassel <larry.bassel@xxxxxxxxxx>
Date: Thu, 5 Jan 2017 09:23:33 -0800
The command "shutdown -h -H now" should shut the system down to the
OBP, however the machine was being powered off in the LDOM case.
In the LDOM case, the "reboot-command" variable must be set to
the string "noop" and then ldom_reboot() must be called.
This will make the OBP ignore the setting of "auto-boot?" after it
completes the reset. This causes the system to stop at the ok prompt.
Signed-off-by: Larry Bassel <larry.bassel@xxxxxxxxxx>
This really doesn't make any sense.
The purpose of shutting down to the "OK" prompt is to inspect the
system state using OBP commands from the context of the currently
running kernel boot.
If you allow the software reset to happen and then force a stop at the
"OK" prompt, the intention of the facility has been completely
compromised so this is pointless.
User's who want the behavior you mention can get it by setting the
reboot-command variable from userspace using the 'eeprom' or similar
commands, and then simply reboot.
I am not applying this patch, sorry.
My apologies for the delayed response.
I've gotten feedback from several Oracle people (copied on this
email) that my explanation for why this patch is useful is incomplete:
1. The variable "reboot-command" isn't one of the usual nvram variables,
it's magic and expected to be used for purposes like this (as Solaris
already does). It's not like "boot-device" which sets a permanent default.
It's cleared when it's used by OpenBoot.
2. It's how you can reboot to an alternate kernel once or reboot from
an alternate boot device once, without changing the permanent default.
I'd appreciate it if you'd reconsider accepting this patch.
Another important point is that you shouldn't re-enter the OBP after the
OS was booted.
After the OS is booted, the configuration of a domain can be dynamically
changed by adding/removing resources (in particular cpu/memory). However,
the OBP won't be aware of any of these changes. So if you return to the
OBP, the OBP might have an inaccurate knowledge of the configuration, and
you can have unpredictable behavior.
That's precisely why Solaris actually removes the OBP right after Solaris
takes control, and effectively prevents returning to the OBP.
So it makes sense to reset the domain before returning to the OBP.
Rgds,
alex.
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