Add preliminary support for binding interrupts to CPUs:

- Add a new intr_event method ie_assign_cpu() that is invoked when the MI
  code wishes to bind an interrupt source to an individual CPU.  The MD
  code may reject the binding with an error.  If an assign_cpu function
  is not provided, then the kernel assumes the platform does not support
  binding interrupts to CPUs and fails all requests to do so.
- Bind ithreads to CPUs on their next execution loop once an interrupt
  event is bound to a CPU.  Only shared ithreads are bound.  We currently
  leave private ithreads for drivers using filters + ithreads in the
  INTR_FILTER case unbound.
- A new intr_event_bind() routine is used to bind an interrupt event to
  a CPU.
- Implement binding on amd64 and i386 by way of the existing pic_assign_cpu
  PIC method.
- For x86, provide a 'intr_bind(IRQ, cpu)' wrapper routine that looks up
  an interrupt source and binds its interrupt event to the specified CPU.
  MI code can currently (ab)use this by doing:

	intr_bind(rman_get_start(irq_res), cpu);

  however, I plan to add a truly MI interface (probably a bus_bind_intr(9))
  where the implementation in the x86 nexus(4) driver would end up calling
  intr_bind() internally.

Requested by:	kmacy, gallatin, jeff
Tested on:	{amd64, i386} x {regular, INTR_FILTER}

1 files changed, 3 insertions, 0 deletions

diff --git a/sys/i386/include/intr_machdep.h b/sys/i386/include/intr_machdep.h
index 4e6d070..2aeb0c9 100644
--- a/sys/i386/include/intr_machdep.h
+++ b/sys/i386/include/intr_machdep.h
@@ -133,6 +133,9 @@ void	intr_add_cpu(u_int cpu);
 #endif
 int	intr_add_handler(const char *name, int vector, driver_filter_t filter,
     driver_intr_t handler, void *arg, enum intr_type flags, void **cookiep);
+#ifdef SMP
+int	intr_bind(u_int vector, u_char cpu);
+#endif
 int	intr_config_intr(int vector, enum intr_trigger trig,
     enum intr_polarity pol);
 void	intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame);