[Libre-soc-bugs] [Bug 325] create POWER9 TRAP pipeline

bugzilla-daemon at libre-soc.org bugzilla-daemon at libre-soc.org
Wed Jul 22 15:05:43 BST 2020


--- Comment #106 from Luke Kenneth Casson Leighton <lkcl at lkcl.net> ---
v3.0B p952

Programming Note

If LEV **IN POWERISA FIELD NOTATION ORDER** == 1 the hypervisor is invoked.
This is the only
way that executing an instruction can cause hyper-
visor state to be entered.

Because this instruction is not privileged, it is possi-
ble for application software to invoke the hypervi-
sor. However, such invocation should be
considered a programming error.

except, V3.0B book I chapter 1 section 1.3.3 has nothing to say about
Reserved fields except by referring us to section 1.8, which *still*
does not have anything to say.. or it does... by circularly referring
in section 1.9.2...

ok, yes: LEV > 1, by being "reservded", should trigger "illegal instruction"
however because we are not supporting hypervisor i believe that LEV=1
should *also* raise illegal instruction (where it can be sorted out
from there).

i will check with openpower-hdl-cores.

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