[PATCH 3/5] irqchip/gic-v5: Synchronize CPU interface disable

The write disabling the GICv5 CPU interface is only guaranteed to take
effect after a context synchronization event. Without one, execution can
return from gicv5_cpu_disable_interrupts() while an interrupt is still
able to be taken.

Add an ISB after the ICC_CR0_EL1 write to ensure interrupts are
disabled before the function returns. No corresponding ISB is added
when enabling the interface, as interrupt delivery is asynchronous and
there is no obvious benefit to waiting for it.

Fixes: 7ec80fb3f025 ("irqchip/gic-v5: Add GICv5 PPI support")
Link: https://sashiko.dev/#/patchset/[email protected]?part=6
Signed-off-by: Sascha Bischoff <[email protected]>
---
 drivers/irqchip/irq-gic-v5.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/irqchip/irq-gic-v5.c b/drivers/irqchip/irq-gic-v5.c
index e9d1795235a66..6a99c541b559b 100644
--- a/drivers/irqchip/irq-gic-v5.c
+++ b/drivers/irqchip/irq-gic-v5.c
@@ -983,6 +983,7 @@ static void gicv5_cpu_disable_interrupts(void)
 
 	cr0 = FIELD_PREP(ICC_CR0_EL1_EN, 0);
 	write_sysreg_s(cr0, SYS_ICC_CR0_EL1);
+	isb();
 }
 
 static void gicv5_cpu_enable_interrupts(void)
-- 
2.34.1