These CPUs use an enhanced layout of the interrupt vector dispatch
and dispatch status registers in order to allow sending IPIs to
multiple targets simultaneously. Thus support for these CPUs was
put in a newly added cheetah_ipi_selected(). This is intended to
be pointed to by cpu_ipi_selected, which now is a function pointer,
in order to avoid cpu_impl checks once booted. Alternatively it
can point to spitfire_ipi_selected(), which was renamed from
cpu_ipi_selected(). Consequently cpu_ipi_send() was also renamed
to spitfire_ipi_send() (there's no need for a cheetah equivalent
of this so far). Initialization of the cpu_ipi_selected pointer
and other requirements is done in mp_init(), which was renamed
from mp_tramp_alloc(), as cpu_mp_start() isn't called on UP
systems while cpu_ipi_selected() is. As a side-effect this allows
to make mp_tramp static to sys/sparc64/sparc64/mp_machdep.c.
For the sake of avoiding #ifdef SMP and for keeping the history in
place cheetah_ipi_selected() and spitfire_ipi_{selected,send}()
where not put into/moved to sys/sparc64/sparc64/{cheetah,spitfire}.c
- Add some CTASSERTs and KASSERTs ensuring that MAXCPU doesn't
exceed the data types we use to store the CPU bit fields or the
number of USIII and greater CPUs supported by the current
cheetah_ipi_selected() implementation (which for JBus-CPUs is
only 4; that should be fine though as according to OpenSolaris
there are no sun4u machines with more than 4 JBus-CPUs).
- In cpu_mp_start() don't enumerate and start more than MAXCPU CPUs
as we can't handle more than that.
- In cpu_mp_start() check for upa-portid vs. portid depending on
cpu_impl for consistency with nexus(4).
- In spitfire_ipi_selected() add KASSERTs ensuring that a CPU isn't
told to IPI itself as sun4u CPUs just can't do that.
- In spitfire_ipi_send() do a MEMBAR #Sync after writing the
interrupt vector data as we want to make sure the payload was
actually written before we trigger the dispatch.
- In spitfire_ipi_send() also verify IDR_BUSY when checking whether
the dispatch was successful as it has to be cleared for this to
be the case.
- Remove some redundant variables.
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