From: Marc Zyngier <marc.zyngier@xxxxxxx>
commit 059e232089e45b0befc9933d31209c225e08b426 upstream.
On systems where a single CPU is present, the GIC may not support
having SGIs delivered to a target list. In that case, we use the
self-SGI mechanism to allow the interrupt to be delivered locally.
Cc: <stable@xxxxxxxxxxxxxxx> # 4.7.x
Tested-by: Fabio Estevam <fabio.estevam@xxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxx>
---
Changes since v1:
- Add the 4.7.x notation
drivers/irqchip/irq-gic.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index c2cab57..390fac5 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -769,6 +769,13 @@ static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
int cpu;
unsigned long flags, map = 0;
+ if (unlikely(nr_cpu_ids == 1)) {
+ /* Only one CPU? let's do a self-IPI... */
+ writel_relaxed(2 << 24 | irq,
+ gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT);
+ return;
+ }
+
raw_spin_lock_irqsave(&irq_controller_lock, flags);
/* Convert our logical CPU mask into a physical one. */
--
1.9.1
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