PowerPC POWER10 updates to dcbf, sync and wait instructions

[Bill Schmidt]

On 5/18/20 8:04 PM, Alan Modra wrote:
> On Mon, May 18, 2020 at 04:40:24PM -0500, Peter Bergner wrote:
>> On 5/18/20 3:03 PM, Tulio Magno Quites Machado Filho wrote:
>>> Power ISA 3.1 states the following (page 1038):
>>>
>>>      The encodings for dcbfps, dcbstps, plwsync, and phwsync were chosen to
>>>      enable software developed to control updates to persistent storage on
>>>      processors that comply with Version 3.1 and subsequent versions of the
>>>      architecture to run compatibly on the POWER9 processor.
>>>
>>> So, I think these instructions should be available on POWER9 too.
>> [snip]
>>> Likewise here.
>>> Power ISA 3.1, page 1087, figure 5 better describes how they're executed on
>>> earlier processors.
>> I don't think this is saying we should enable the new mnemonics on POWER9,
>> but rather if one of these is assembled for POWER10, that they'll run on
>> POWER9 just fine.  Ditto for the sync insns.
>>
>> Alan or Bill,
>>
>> How do you read those paragraphs?
> With the same conclusion as you do.
>
Likewise.