Part of waitpkg is the TPAUSE instruction. This instruction gives an
RDTSC deadline to go in to a low power sleep mode with the CPU.
Semantically we can't implement umonitor and umwait with ARM's exclusive
monitor implementation, but a nop implementation is sane. Just need to
make sure to clear the pre-req flags.
This lowers power consumption of UE5 games since their job handler now
goes to a tpause based implementation instead of a `pause` spinloop
implementation.
The MIDR querying is inherently OS specific and needs a bit of special
casing. Instead let the frontend inform FEXCore how many CPU cores there
are and their MIDRs instead.
This lets us keep the Linux specific code in the frontend.
If we query the CPU flags ourselves then vixl is no longer a
compile-time or runtime dependency unless the vixl disassembler or
simulator is built.
A bit spicy from all the feature bits we need to load up.
These are only missing if using the hostrunner and the CI machine
doesn't support that particular feature. FEX otherwise always supports
these feature flags so they don't need to exist as options.
Just check the feature bit directly in the HostRunner frontend for these
bits.
This moves the CPU feature querying to the frontend. The primary purpose
here is for the wow64 frontend to not require linux-isms for querying
these features. This is required since non-Linux environments don't have
the "CPUID" feature for reading EL1 MSRs in EL0.
Wiring up the remaining wow64 registry querying is left for a future
exercise.
This also technically removes an xbyak requirement from FEXCore for when
building the x86 Test harness runner, but that doesn't really matter for
regular use cases.
Ryan Houdek