[PARISC] Allow nested interrupts

Our prior mode of operation didn't allow nested interrupts
because it makes the interrupt code much simpler.  However,
nested interrupts are better for latency.

This code uses the EIEM register to simulate level interrupts
and thus achieve nesting.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index f33e8de438dc..faad338f310e 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -262,6 +262,9 @@ ipi_interrupt(int irq, void *dev_id, struct pt_regs *regs)
                                         this_cpu, which);
                                 return IRQ_NONE;
                         } /* Switch */
+                /* let in any pending interrupts */
+                local_irq_enable();
+                local_irq_disable();
                 } /* while (ops) */
         }
         return IRQ_HANDLED;