Alexander Graf <address@hidden> writes:
On 17.06.14 11:59, Nikunj A Dadhania wrote:
Alexander Graf <address@hidden> writes:
On 17.06.14 11:30, Nikunj A Dadhania wrote:
Alexander Graf <address@hidden> writes:
+ spapr_rtas_register("ibm,os-term", rtas_ibm_os_term);
+ spapr_rtas_register("ibm,extended-os-term", rtas_ibm_ext_os_term);
Why do we need the extended-os-term if we don't do anything with it?
Linux kernel checks for both of them because of legacy:
arch/powerpc/kernel/rtas.c:
void rtas_os_term(char *str)
{
[...]
/*
* Firmware with the ibm,extended-os-term property is guaranteed
* to always return from an ibm,os-term call. Earlier versions
without
* this property may terminate the partition which we want to avoid
* since it interferes with panic_timeout.
But we do not return from the RTAS call, so we don't adhere to the
extended semantics?
But you would return without calling os-term call if
ibm,extended-os-term isnt registered. For that reason I h ave defined a
stub.
I appreciate the hacker mentality, but Linux explicitly checks on
ibm,extended-os-term to ensure that the hypervisor does not stop the VM
when it calls ibm,os-term. However, the implementation above does stop
the VM when the guest calls ibm,os-term.
Seems to be added to do just that:
commit e9bbc8cde0e3c33b42ddbe1b02108cb5c97275eb
Author: Anton Blanchard <address@hidden>
Date: Thu Feb 18 12:11:51 2010 +0000
powerpc/pseries: Call ibm,os-term if the ibm,extended-os-term is present
We have had issues in the past with ibm,os-term initiating shutdown of a
partition. This is confusing to the user, especially if panic_timeout is
non zero.
The temporary fix was to avoid calling ibm,os-term if a panic_timeout was set
and since we set it on every boot we basically never call ibm,os-term.
An extended version of ibm,os-term has since been implemented which gives us
the behaviour we want:
"When the platform supports extended ibm,os-term behavior, the return to the
RTAS will always occur unless there is a kernel assisted dump active as
initiated by an ibm,configure-kernel-dump call."
This patch checks for the ibm,extended-os-term property and calls ibm,os-term
if it exists.
Signed-off-by: Anton Blanchard <address@hidden>
Signed-off-by: Benjamin Herrenschmidt <address@hidden>