Re: [PATCH] sparc64: shut down to OBP correctly

[Larry Bassel <larry.bassel@oracle.com>]

On 21 Dec 16 13:07, David Miller wrote:
> From: Larry Bassel <larry.bassel@oracle.com>
> Date: Wed, 21 Dec 2016 09:12:13 -0800
> 
> > Orabug: 24789774
> > 
> > The command "shutdown -h -H now" should shut down the system to
> > OBP, however the machine was incorrectly being powered off instead
> > (on both LDOM and bare metal).
> > 
> > The "exit" command to the OBP must be run and then a hard
> > loop to prevent return to the kernel.
> > 
> > Signed-off-by: Larry Bassel <larry.bassel@oracle.com>
> 
> On LDOM, once you boot past the early stages of the kernel, OBP is
> considered volatile and thus unusable.

My code does work on an 4.9.0 LDOM (we get to the ok prompt). So you're saying
this was a "lucky accident" and there is no "clean" way of getting back to
the OBP when we are in a LDOM (i.e. all we can do is power off which is
what the current code does)?

> 
> That's why I did a direct LDOM shutdown here.

Unfortunately, the variable "ldom_domaining_enabled" is 1 even when
we are not in an LDOM (I just double checked this by printing
the value out as we shut down) and so the current code will power off in
the bare metal case as well. Is there is a good way of determining that
we are running on bare metal?

Thanks.

Larry

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