sparc32, sun4d: Implemented SMP IPIs support for SUN4D machines
The sun4d does not seem to have a distingstion between soft and hard
IRQs. When generating IPIs the generated IRQ looks like a hard IRQ,
this patch adds a "IPI check" in the sun4d irq trap handler at a
predefined IRQ number (SUN4D_IPI_IRQ). Before generating an IPI
a per-cpu memory structure is modified for the "IPI check" to
successfully detect a IPI request to a specific processor, the check
clears the IPI work requested.
All three IPIs (resched, single and cpu-mask) use the same IRQ
number.
The IPI IRQ should preferrably be on a separate IRQ and definitly
not shared with IRQ handlers requesting IRQ with IRQF_SHARED.
Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/kernel/sun4d_irq.c b/arch/sparc/kernel/sun4d_irq.c
index b830914..a9ea60e 100644
--- a/arch/sparc/kernel/sun4d_irq.c
+++ b/arch/sparc/kernel/sun4d_irq.c
@@ -156,6 +156,15 @@
cc_set_iclr(1 << pil);
+#ifdef CONFIG_SMP
+ /*
+ * Check IPI data structures after IRQ has been cleared. Hard and Soft
+ * IRQ can happen at the same time, so both cases are always handled.
+ */
+ if (pil == SUN4D_IPI_IRQ)
+ sun4d_ipi_interrupt();
+#endif
+
old_regs = set_irq_regs(regs);
irq_enter();
if (sbusl == 0) {