[Skiboot] [PATCH v2] core/init: Add ibm, processor-storage-keys property to /cpus DT node.
Thiago Jung Bauermann
bauerman at linux.vnet.ibm.com
Wed Oct 18 13:09:13 AEDT 2017
Thiago Jung Bauermann <bauerman at linux.vnet.ibm.com> writes:
> LoPAPR says:
>
> “ibm,processor-storage-keys”
>
> property name indicating the number of virtual storage keys supported
> by the processor described by this node.
>
> prop-encoded-array: Consists of two cells encoded as with encode-int.
> The first cell represents the number of virtual storage keys supported
> for data accesses while the second cell represents the number of
> virtual storage keys supported for instruction accesses. The cell value
> of zero indicates that no storage keys are supported for the access
> type.
>
> pHyp provides the property above but there's a bug in P8 firmware where the
> second cell is zero even though POWER8 supports instruction access keys.
> This bug will be fixed for P9.
>
> While this is a PAPR property, it's useful to have it in powernv as well
> so that Linux has a uniform way of checking for the feature regardless of
> the platform it's running on.
>
> On PAPR there is one property for each CPU node, but since it's highly
> unlikely that different CPUs will support a different number of keys, we
> put the property in the /cpus node instead.
>
> Tested on QEMU POWER8 powernv model and Mambo P9.
>
> Signed-off-by: Thiago Jung Bauermann <bauerman at linux.vnet.ibm.com>
> ---
> core/init.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> Changes in v2:
> - Put property in /cpus instead of in each CPU node.
Ping?
--
Thiago Jung Bauermann
IBM Linux Technology Center
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