Messages in this thread | | | Date | Wed, 8 Apr 2020 15:20:33 +0530 | From | Gautham R Shenoy <> | Subject | Re: [RFC] Support stop state version quirk and firmware enabled stop |
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Hi Pratik,
On Wed, Mar 04, 2020 at 09:26:48PM +0530, Pratik Rajesh Sampat wrote: > A concept patch in Skiboot to illustrate the case wherein handling of > stop states for different DD versions of a CPU can be achieved by a > simple modification in the list of cpu_features. > As an example idle-stop1 is defined which uses P9_CPU_DD1 to define the > cpu feature. > > Along with that, an implementation is being worked upon the LE OPAL > series which helps OPAL handle the stop state entry and exit. > > This patch advertises this capability of the firmware which can be > availed if the quirk-version-setting is not cognizable. > > The firmware-enabled stop is being worked by Abhishek Goel > <huntbag@linux.vnet.ibm.com> building upon the LE OPAL series. > > Signed-off-by: Pratik Rajesh Sampat <psampat@linux.ibm.com> > --- > core/cpufeatures.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/core/cpufeatures.c b/core/cpufeatures.c > index ec30c975..b9875e7b 100644 > --- a/core/cpufeatures.c > +++ b/core/cpufeatures.c > @@ -510,6 +510,25 @@ static const struct cpu_feature cpu_features_table[] = { > -1, -1, -1, > NULL, }, > > + /* > + * QUIRK for ISAv3.0B stop idle instructions and registers > + * Helps us determine if there are any quirks > + * XXX: Same of idle-stop > + */ > + { "idle-stop-v1", > + CPU_P9_DD1, > + ISA_V3_0B, USABLE_HV|USABLE_OS, > + HV_CUSTOM, OS_CUSTOM, > + -1, -1, -1, > + NULL, },
So, at this point, we don't need any such quirk for any of the DD version right ? This is to demonstrate that if say P9_DD1 had a quirk w.r.t stop-state handling, then this is how we would advertise it to the kernel.
> + > + { "firmware-stop-supported", > + CPU_P9, > + ISA_V3_0B, USABLE_HV|USABLE_OS, > + HV_CUSTOM, OS_CUSTOM, > + -1, -1, -1, > + NULL, }, > +
I suppose this is for the opal-cpuidle driver support posted here: https://lists.ozlabs.org/pipermail/skiboot/2020-April/016726.html
> /* > * ISAv3.0B Hypervisor Virtualization Interrupt > * Also associated system registers, LPCR EE, HEIC, HVICE, > @@ -883,6 +902,9 @@ static void add_cpufeatures(struct dt_node *cpus, > const struct cpu_feature *f = &cpu_features_table[i]; > > if (f->cpus_supported & cpu_feature_cpu) { > + if (!strcmp(f->name, "firmware-stop-supported") && > + HAVE_BIG_ENDIAN) > + continue;
In OPAL do we have an macro defining BIG_ENDIAN ? If yes, you could wrap the "firmware-stop-supported" in cpu_features_table[] within #ifndef BIG_ENDIAN. That way you won't need a special case here.
> DBG(" '%s'\n", f->name); > add_cpu_feature_nodeps(features, f); > } > -- > 2.24.1 >
-- Thanks and Regards gautham.
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