[PATCH 5.9 013/255] irqchip/sifive-plic: Fix broken irq_set_affinity() callback

Greg Kroah-Hartman
2020-11-17T13:31:09Z

From: Greentime Hu <greentime.hu@sifive.com>

[ Upstream commit a7480c5d725c4ecfc627e70960f249c34f5d13e8 ]

An interrupt submitted to an affinity change will always be left enabled
after plic_set_affinity() has been called, while the expectation is that
it should stay in whatever state it was before the call.

Preserving the configuration fixes a PWM hang issue on the Unleashed
board.

[ 919.015783] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 919.020922] rcu: 0-...0: (0 ticks this GP)
idle=7d2/1/0x4000000000000002 softirq=1424/1424 fqs=105807
[ 919.030295] (detected by 1, t=225825 jiffies, g=1561, q=3496)
[ 919.036109] Task dump for CPU 0:
[ 919.039321] kworker/0:1 R running task 0 30 2 0x00000008
[ 919.046359] Workqueue: events set_brightness_delayed
[ 919.051302] Call Trace:
[ 919.053738] [<ffffffe000930d92>] __schedule+0x194/0x4de
[ 982.035783] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 982.040923] rcu: 0-...0: (0 ticks this GP)
idle=7d2/1/0x4000000000000002 softirq=1424/1424 fqs=113325
[ 982.050294] (detected by 1, t=241580 jiffies, g=1561, q=3509)
[ 982.056108] Task dump for CPU 0:
[ 982.059321] kworker/0:1 R running task 0 30 2 0x00000008
[ 982.066359] Workqueue: events set_brightness_delayed
[ 982.071302] Call Trace:
[ 982.073739] [<ffffffe000930d92>] __schedule+0x194/0x4de
[..]

Fixes: bb0fed1c60cc ("irqchip/sifive-plic: Switch to fasteoi flow")
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
[maz: tidy-up commit message]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20201020081532.2377-1-greentime.hu@sifive.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/irqchip/irq-sifive-plic.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index eaa3e9fe54e91..4048657ece0ac 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -151,7 +151,7 @@ static int plic_set_affinity(struct irq_data *d,
return -EINVAL;

plic_irq_toggle(&priv->lmask, d, 0);
- plic_irq_toggle(cpumask_of(cpu), d, 1);
+ plic_irq_toggle(cpumask_of(cpu), d, !irqd_irq_masked(d));

irq_data_update_effective_affinity(d, cpumask_of(cpu));

--
2.27.0